diff --git a/.gitattributes b/.gitattributes index c009a5d4df6496a042bba7aaba7c2a30822707df..09a0af0a39740301f7f2ba62e9840d7b52c8078c 100644 --- a/.gitattributes +++ b/.gitattributes @@ -3258,3 +3258,67 @@ saved_model/**/* filter=lfs diff=lfs merge=lfs -text 2023/MBPTrack_[[:space:]]Improving[[:space:]]3D[[:space:]]Point[[:space:]]Cloud[[:space:]]Tracking[[:space:]]with[[:space:]]Memory[[:space:]]Networks[[:space:]]and[[:space:]]Box[[:space:]]Priors/956ae52e-1f1a-4203-9786-92a3a80682aa_origin.pdf filter=lfs diff=lfs merge=lfs -text 2023/MDCS_[[:space:]]More[[:space:]]Diverse[[:space:]]Experts[[:space:]]with[[:space:]]Consistency[[:space:]]Self-distillation[[:space:]]for[[:space:]]Long-tailed[[:space:]]Recognition/4759726a-56c7-4e00-9a4a-80fbdc668438_origin.pdf filter=lfs diff=lfs merge=lfs -text 2023/MEFLUT_[[:space:]]Unsupervised[[:space:]]1D[[:space:]]Lookup[[:space:]]Tables[[:space:]]for[[:space:]]Multi-exposure[[:space:]]Image[[:space:]]Fusion/601a9827-54df-4685-968b-72e1c7050277_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MEGA_[[:space:]]Multimodal[[:space:]]Alignment[[:space:]]Aggregation[[:space:]]and[[:space:]]Distillation[[:space:]]For[[:space:]]Cinematic[[:space:]]Video[[:space:]]Segmentation/014aa68e-4ee6-4ed7-996a-a0fac673a258_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MGMAE_[[:space:]]Motion[[:space:]]Guided[[:space:]]Masking[[:space:]]for[[:space:]]Video[[:space:]]Masked[[:space:]]Autoencoding/913ed268-24e1-487c-b23b-995e3fca2c86_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MHCN_[[:space:]]A[[:space:]]Hyperbolic[[:space:]]Neural[[:space:]]Network[[:space:]]Model[[:space:]]for[[:space:]]Multi-view[[:space:]]Hierarchical[[:space:]]Clustering/803b20b8-8ea9-4642-8b2e-1e4d0ac18614_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MHEntropy_[[:space:]]Entropy[[:space:]]Meets[[:space:]]Multiple[[:space:]]Hypotheses[[:space:]]for[[:space:]]Pose[[:space:]]and[[:space:]]Shape[[:space:]]Recovery/f9c54455-f324-48c7-9865-4e8d15caf336_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MI-GAN_[[:space:]]A[[:space:]]Simple[[:space:]]Baseline[[:space:]]for[[:space:]]Image[[:space:]]Inpainting[[:space:]]on[[:space:]]Mobile[[:space:]]Devices/af22c1bd-1590-4032-ac12-a1b776021514_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MIMO-NeRF_[[:space:]]Fast[[:space:]]Neural[[:space:]]Rendering[[:space:]]with[[:space:]]Multi-input[[:space:]]Multi-output[[:space:]]Neural[[:space:]]Radiance[[:space:]]Fields/323ff8ab-5b3c-4603-a4d5-667546c604d5_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MMST-ViT_[[:space:]]Climate[[:space:]]Change-aware[[:space:]]Crop[[:space:]]Yield[[:space:]]Prediction[[:space:]]via[[:space:]]Multi-Modal[[:space:]]Spatial-Temporal[[:space:]]Vision[[:space:]]Transformer/8b54a15b-f3ee-46da-88b3-5c8950b9cb49_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MMVP_[[:space:]]Motion-Matrix-Based[[:space:]]Video[[:space:]]Prediction/2d057465-769a-4de5-aaaa-89b4c330116e_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MODA_[[:space:]]Mapping-Once[[:space:]]Audio-driven[[:space:]]Portrait[[:space:]]Animation[[:space:]]with[[:space:]]Dual[[:space:]]Attentions/cd6d82fe-3030-4ffc-8902-e0f3febe9ace_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MOSE_[[:space:]]A[[:space:]]New[[:space:]]Dataset[[:space:]]for[[:space:]]Video[[:space:]]Object[[:space:]]Segmentation[[:space:]]in[[:space:]]Complex[[:space:]]Scenes/aa32c686-8817-467e-b52a-3ad29e222646_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MOST_[[:space:]]Multiple[[:space:]]Object[[:space:]]Localization[[:space:]]with[[:space:]]Self-Supervised[[:space:]]Transformers[[:space:]]for[[:space:]]Object[[:space:]]Discovery/b6bef65d-9eb6-4535-9de8-7c08bf88dd4b_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MPCViT_[[:space:]]Searching[[:space:]]for[[:space:]]Accurate[[:space:]]and[[:space:]]Efficient[[:space:]]MPC-Friendly[[:space:]]Vision[[:space:]]Transformer[[:space:]]with[[:space:]]Heterogeneous[[:space:]]Attention/844d9362-4725-44da-8709-8687e3c64eb2_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MPI-Flow_[[:space:]]Learning[[:space:]]Realistic[[:space:]]Optical[[:space:]]Flow[[:space:]]with[[:space:]]Multiplane[[:space:]]Images/d01da3cc-92b1-43b1-b6d0-867a68823626_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MRM_[[:space:]]Masked[[:space:]]Relation[[:space:]]Modeling[[:space:]]for[[:space:]]Medical[[:space:]]Image[[:space:]]Pre-Training[[:space:]]with[[:space:]]Genetics/3ca9548a-636d-4952-80cd-106e032bd384_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MRN_[[:space:]]Multiplexed[[:space:]]Routing[[:space:]]Network[[:space:]]for[[:space:]]Incremental[[:space:]]Multilingual[[:space:]]Text[[:space:]]Recognition/6ed06787-7eb3-4534-9eb1-83af9b81cded_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MSI_[[:space:]]Maximize[[:space:]]Support-Set[[:space:]]Information[[:space:]]for[[:space:]]Few-Shot[[:space:]]Segmentation/18b3712a-f7d6-4a6b-8811-754fd084ad1d_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MST-compression_[[:space:]]Compressing[[:space:]]and[[:space:]]Accelerating[[:space:]]Binary[[:space:]]Neural[[:space:]]Networks[[:space:]]with[[:space:]]Minimum[[:space:]]Spanning[[:space:]]Tree/9bf308bf-7020-43ef-9313-33d2e81da894_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MULLER_[[:space:]]Multilayer[[:space:]]Laplacian[[:space:]]Resizer[[:space:]]for[[:space:]]Vision/540b48e0-0e9c-4eba-a984-866547201e9c_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MUVA_[[:space:]]A[[:space:]]New[[:space:]]Large-Scale[[:space:]]Benchmark[[:space:]]for[[:space:]]Multi-View[[:space:]]Amodal[[:space:]]Instance[[:space:]]Segmentation[[:space:]]in[[:space:]]the[[:space:]]Shopping[[:space:]]Scenario/4b78daa4-2084-48f2-bdbe-f8d1b9a4826f_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MUter_[[:space:]]Machine[[:space:]]Unlearning[[:space:]]on[[:space:]]Adversarially[[:space:]]Trained[[:space:]]Models/794014c8-e2b9-40ef-b0f6-0010a00c9a4d_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MV-DeepSDF_[[:space:]]Implicit[[:space:]]Modeling[[:space:]]with[[:space:]]Multi-Sweep[[:space:]]Point[[:space:]]Clouds[[:space:]]for[[:space:]]3D[[:space:]]Vehicle[[:space:]]Reconstruction[[:space:]]in[[:space:]]Autonomous[[:space:]]Driving/0f77204f-207d-45fd-9794-f340dac7f292_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MV-Map_[[:space:]]Offboard[[:space:]]HD-Map[[:space:]]Generation[[:space:]]with[[:space:]]Multi-view[[:space:]]Consistency/59188c7c-19e6-4a92-b752-2ffcc7690379_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MVPSNet_[[:space:]]Fast[[:space:]]Generalizable[[:space:]]Multi-view[[:space:]]Photometric[[:space:]]Stereo/0b36b82c-cf6a-406b-8b06-65bc02693944_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MagicFusion_[[:space:]]Boosting[[:space:]]Text-to-Image[[:space:]]Generation[[:space:]]Performance[[:space:]]by[[:space:]]Fusing[[:space:]]Diffusion[[:space:]]Models/40801689-afc7-4c4a-b4e3-8cbca2d70a56_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Make[[:space:]]Encoder[[:space:]]Great[[:space:]]Again[[:space:]]in[[:space:]]3D[[:space:]]GAN[[:space:]]Inversion[[:space:]]through[[:space:]]Geometry[[:space:]]and[[:space:]]Occlusion-Aware[[:space:]]Encoding/d0a41b80-a701-4955-834c-d42058b2d111_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Make-An-Animation_[[:space:]]Large-Scale[[:space:]]Text-conditional[[:space:]]3D[[:space:]]Human[[:space:]]Motion[[:space:]]Generation/0b6ce6f5-40a5-4972-8f2c-3c7fc7288f3d_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Make-It-3D_[[:space:]]High-fidelity[[:space:]]3D[[:space:]]Creation[[:space:]]from[[:space:]]A[[:space:]]Single[[:space:]]Image[[:space:]]with[[:space:]]Diffusion[[:space:]]Prior/3c32b216-e73e-471f-8cad-0ce51b8a9a7c_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Manipulate[[:space:]]by[[:space:]]Seeing_[[:space:]]Creating[[:space:]]Manipulation[[:space:]]Controllers[[:space:]]from[[:space:]]Pre-Trained[[:space:]]Representations/4fa47878-d18c-4c5d-89a6-b50ae3093aaf_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MapFormer_[[:space:]]Boosting[[:space:]]Change[[:space:]]Detection[[:space:]]by[[:space:]]Using[[:space:]]Pre-change[[:space:]]Information/8472e89b-fe96-412d-8c9c-414b2c42d2f3_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MapPrior_[[:space:]]Bird's-Eye[[:space:]]View[[:space:]]Map[[:space:]]Layout[[:space:]]Estimation[[:space:]]with[[:space:]]Generative[[:space:]]Models/80d4c617-535f-4e51-ba9c-d279342878ed_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/March[[:space:]]in[[:space:]]Chat_[[:space:]]Interactive[[:space:]]Prompting[[:space:]]for[[:space:]]Remote[[:space:]]Embodied[[:space:]]Referring[[:space:]]Expression/dfdb2c34-61fe-4960-a099-a29f68122739_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Markov[[:space:]]Game[[:space:]]Video[[:space:]]Augmentation[[:space:]]for[[:space:]]Action[[:space:]]Segmentation/3ebb7b09-a6e7-4446-89ff-eb9741fd0b7f_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MasQCLIP[[:space:]]for[[:space:]]Open-Vocabulary[[:space:]]Universal[[:space:]]Image[[:space:]]Segmentation/0636ab48-f4a3-4a28-9365-8ed3c11dca4b_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MasaCtrl_[[:space:]]Tuning-Free[[:space:]]Mutual[[:space:]]Self-Attention[[:space:]]Control[[:space:]]for[[:space:]]Consistent[[:space:]]Image[[:space:]]Synthesis[[:space:]]and[[:space:]]Editing/6e476140-cab6-422d-9817-a489e1ead454_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Mask-Attention-Free[[:space:]]Transformer[[:space:]]for[[:space:]]3D[[:space:]]Instance[[:space:]]Segmentation/2a13e96b-8070-4a45-a596-f26ce5eefa9a_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Masked[[:space:]]Autoencoders[[:space:]]Are[[:space:]]Stronger[[:space:]]Knowledge[[:space:]]Distillers/801459a1-6a61-45c0-b371-eb489abaf84f_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Masked[[:space:]]Autoencoders[[:space:]]are[[:space:]]Efficient[[:space:]]Class[[:space:]]Incremental[[:space:]]Learners/3431d5c0-b1b6-47da-9e6e-bca6fba5a382_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Masked[[:space:]]Diffusion[[:space:]]Transformer[[:space:]]is[[:space:]]a[[:space:]]Strong[[:space:]]Image[[:space:]]Synthesizer/a412e570-59ba-43e9-aea5-2909edb799b1_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Masked[[:space:]]Motion[[:space:]]Predictors[[:space:]]are[[:space:]]Strong[[:space:]]3D[[:space:]]Action[[:space:]]Representation[[:space:]]Learners/06acdbbe-e15b-4021-a13d-3cb042fcaf0d_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Masked[[:space:]]Retraining[[:space:]]Teacher-Student[[:space:]]Framework[[:space:]]for[[:space:]]Domain[[:space:]]Adaptive[[:space:]]Object[[:space:]]Detection/5a41b22e-9755-4ada-9123-4e6d5ca57c32_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Masked[[:space:]]Spatio-Temporal[[:space:]]Structure[[:space:]]Prediction[[:space:]]for[[:space:]]Self-supervised[[:space:]]Learning[[:space:]]on[[:space:]]Point[[:space:]]Cloud[[:space:]]Videos/e14b4021-babf-4da5-a112-3aa5b237ce50_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Masked[[:space:]]Spiking[[:space:]]Transformer/7ef4a39e-394a-4406-bcd4-3ff4096115d4_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Mastering[[:space:]]Spatial[[:space:]]Graph[[:space:]]Prediction[[:space:]]of[[:space:]]Road[[:space:]]Networks/e2e1da73-cf2c-48bb-9b35-8cf5cb0f98fc_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MatrixCity_[[:space:]]A[[:space:]]Large-scale[[:space:]]City[[:space:]]Dataset[[:space:]]for[[:space:]]City-scale[[:space:]]Neural[[:space:]]Rendering[[:space:]]and[[:space:]]Beyond/1fb06bbc-ee8a-4da1-8280-e317a61d1b94_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MatrixVT_[[:space:]]Efficient[[:space:]]Multi-Camera[[:space:]]to[[:space:]]BEV[[:space:]]Transformation[[:space:]]for[[:space:]]3D[[:space:]]Perception/3d8f338d-7ad3-414d-a017-25b8e25151fd_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MeMOTR_[[:space:]]Long-Term[[:space:]]Memory-Augmented[[:space:]]Transformer[[:space:]]for[[:space:]]Multi-Object[[:space:]]Tracking/40deaafe-8b86-4716-a18c-f883acf32105_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MeViS_[[:space:]]A[[:space:]]Large-scale[[:space:]]Benchmark[[:space:]]for[[:space:]]Video[[:space:]]Segmentation[[:space:]]with[[:space:]]Motion[[:space:]]Expressions/422d1f87-df33-4f64-91c1-e11c03538001_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Measuring[[:space:]]Asymmetric[[:space:]]Gradient[[:space:]]Discrepancy[[:space:]]in[[:space:]]Parallel[[:space:]]Continual[[:space:]]Learning/e2e81f44-6f94-4699-81e2-292ae5d4c0a8_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MedKLIP_[[:space:]]Medical[[:space:]]Knowledge[[:space:]]Enhanced[[:space:]]Language-Image[[:space:]]Pre-Training[[:space:]]for[[:space:]]X-ray[[:space:]]Diagnosis/a294a7d4-55de-429f-8329-44c18b938170_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Membrane[[:space:]]Potential[[:space:]]Batch[[:space:]]Normalization[[:space:]]for[[:space:]]Spiking[[:space:]]Neural[[:space:]]Networks/cc22facf-9790-4a7c-8861-ea4adecda7ac_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Memory-and-Anticipation[[:space:]]Transformer[[:space:]]for[[:space:]]Online[[:space:]]Action[[:space:]]Understanding/a1b3a75e-11e3-4ea7-94a7-a5bef15574c1_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MemorySeg_[[:space:]]Online[[:space:]]LiDAR[[:space:]]Semantic[[:space:]]Segmentation[[:space:]]with[[:space:]]a[[:space:]]Latent[[:space:]]Memory/9db8fa07-a91f-4043-9a71-b3d3e6b17388_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Mesh2Tex_[[:space:]]Generating[[:space:]]Mesh[[:space:]]Textures[[:space:]]from[[:space:]]Image[[:space:]]Queries/743afd5f-14b2-4965-bbeb-bded0a673761_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Meta[[:space:]]OOD[[:space:]]Learning[[:space:]]For[[:space:]]Continuously[[:space:]]Adaptive[[:space:]]OOD[[:space:]]Detection/06d792b4-9c42-4f8e-baa6-449a229309f7_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Meta-ZSDETR_[[:space:]]Zero-shot[[:space:]]DETR[[:space:]]with[[:space:]]Meta-learning/ab81a251-c4da-4048-9092-c84f97030f0f_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MetaBEV_[[:space:]]Solving[[:space:]]Sensor[[:space:]]Failures[[:space:]]for[[:space:]]3D[[:space:]]Detection[[:space:]]and[[:space:]]Map[[:space:]]Segmentation/5204095b-1c9c-4150-9f9c-b1c27fdd82da_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MetaF2N_[[:space:]]Blind[[:space:]]Image[[:space:]]Super-Resolution[[:space:]]by[[:space:]]Learning[[:space:]]Efficient[[:space:]]Model[[:space:]]Adaptation[[:space:]]from[[:space:]]Faces/ed6327a3-66bd-4260-9c23-011c9182cd69_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MetaGCD_[[:space:]]Learning[[:space:]]to[[:space:]]Continually[[:space:]]Learn[[:space:]]in[[:space:]]Generalized[[:space:]]Category[[:space:]]Discovery/991c02f6-2cc1-4391-a19c-b8559690aace_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Metric3D_[[:space:]]Towards[[:space:]]Zero-shot[[:space:]]Metric[[:space:]]3D[[:space:]]Prediction[[:space:]]from[[:space:]]A[[:space:]]Single[[:space:]]Image/6cc2d292-7284-48d5-98ac-76d175845d01_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Mimic3D_[[:space:]]Thriving[[:space:]]3D-Aware[[:space:]]GANs[[:space:]]via[[:space:]]3D-to-2D[[:space:]]Imitation/d009dfab-0a08-423e-b77c-b88a4b5cf703_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/MiniROAD_[[:space:]]Minimal[[:space:]]RNN[[:space:]]Framework[[:space:]]for[[:space:]]Online[[:space:]]Action[[:space:]]Detection/ea56ef7d-d0ee-4b4c-86bd-22698b72c0f8_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Minimal[[:space:]]Solutions[[:space:]]to[[:space:]]Generalized[[:space:]]Three-View[[:space:]]Relative[[:space:]]Pose[[:space:]]Problem/21f6bf16-a75f-4e22-8ec8-d9aabd4e98e3_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Minimal[[:space:]]Solutions[[:space:]]to[[:space:]]Uncalibrated[[:space:]]Two-view[[:space:]]Geometry[[:space:]]with[[:space:]]Known[[:space:]]Epipoles/1ff0de2c-2b50-437f-a3e0-afb03703f817_origin.pdf filter=lfs diff=lfs merge=lfs -text +2023/Minimum[[:space:]]Latency[[:space:]]Deep[[:space:]]Online[[:space:]]Video[[:space:]]Stabilization/5c08d8de-7fcf-430c-a7d0-16aae326aed4_origin.pdf filter=lfs diff=lfs merge=lfs -text diff --git a/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/014aa68e-4ee6-4ed7-996a-a0fac673a258_content_list.json b/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/014aa68e-4ee6-4ed7-996a-a0fac673a258_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..43810c6b763f084bd5fadc4c937d54543de9cf86 --- /dev/null +++ b/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/014aa68e-4ee6-4ed7-996a-a0fac673a258_content_list.json @@ -0,0 +1,1598 @@ +[ + { + "type": "text", + "text": "MEGA: Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation", + "text_level": 1, + "bbox": [ + 179, + 130, + 789, + 174 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Najmeh Sadoughi1, Xinyu Li1, Avijit Vajpayee1, David Fan1, Bing Shuai2, Hector Santos-Villalobos1, Vimal Bhat1, Rohith MV1 \n1Amazon Prime Video, 2AWS AI Labs", + "bbox": [ + 189, + 202, + 776, + 255 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{nnnourab,xxnl,avivaj,fandavi,bshuai,hsantosv,vimalb,kurohith}@amazon.com", + "bbox": [ + 161, + 258, + 805, + 273 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 308, + 313, + 325 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Previous research has studied the task of segmenting cinematic videos into scenes and into narrative acts. However, these studies have overlooked the essential task of multimodal alignment and fusion for effectively and efficiently processing long-form videos ( $>60\\mathrm{min}$ ). In this paper, we introduce Multimodal alignmEnt aGgregation and distillAtion (MEGA) for cinematic long-video segmentation. MEGA tackles the challenge by leveraging multiple media modalities. The method coarsely aligns inputs of variable lengths and different modalities with alignment positional encoding. To maintain temporal synchronization while reducing computation, we further introduce an enhanced bottleneck fusion layer which uses temporal alignment. Additionally, MEGA employs a novel contrastive loss to synchronize and transfer labels across modalities, enabling act segmentation from labeled synopsis sentences on video shots. Our experimental results show that MEGA outperforms state-of-the-art methods on MovieNet dataset for scene segmentation (with an Average Precision improvement of $+1.19\\%$ ) and on TRI-POD dataset for act segmentation (with a Total Agreement improvement of $+5.51\\%$ ).", + "bbox": [ + 75, + 342, + 473, + 659 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 691, + 207, + 708 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In the world of video production, movies are composed of smaller units called shots, scenes, and acts. Shots are a continuous set of frames, a scene is a sequence of shots that tell a story, and an act is a thematic section of a narrative [14]. While computer vision has made significant strides in shot detection [39], scene and act segmentation remain a challenge, despite their potential for smart video navigation, advertisement insertion, and movie summarization. Cinematic content comprises of different data sources, including audio, visual, and text data, as well as derivative data sources from the narrative, including location, appearance, tone, or acoustic events. In this work, we will refer to all of these", + "bbox": [ + 75, + 719, + 470, + 900 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/0006a7d310399a74f432bb3da97e518fc571bd114cbb9fb6c04e4fff1ad472ba.jpg", + "image_caption": [ + "Figure 1: MEGA works well on both scene segmentation and act segmentation tasks, outperforming previous work with significant margin. V,T*,T,A denotes video, screenplay, subtitle and audio respectively." + ], + "image_footnote": [], + "bbox": [ + 519, + 310, + 880, + 502 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "input components as \"modalities\" of cinematic content. Previous work has not fully explored how to align and aggregate these modalities which have different granularities.", + "bbox": [ + 496, + 593, + 893, + 638 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "We propose to address scene and act segmentation tasks with an unified multimodal Transformer. However, this approach presents two main challenges. Firstly, there is the issue of cross modality information synchronization and fusion at the shot level. Previous studies which use multimodal fusion for scene and act segmentation perform early [8, 32] or late fusion of features [35], and have not explored fusion strategies which utilize multimodal temporal alignment. Additionally, the fusion strategies that utilize temporal alignment such as merged attention or cross modality attention [9, 21] are computationally expensive and not generalizable to a large number of modalities. Secondly, due to the challenges associated with labeling a long video on act segmentation, the labels for act segmentation are provided on synopsis sentences [30] which do not provide timestamps. To avoid the more challenging task of cross-modal synchronization, previous studies on act segmentation [30, 32] rely", + "bbox": [ + 496, + 643, + 895, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "23331", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "on textual screenplay to transfer the labels from synopsis to movie, ignoring the rich multimodal information from the video, and introducing an additional dependency on screenplay data which is not always available.", + "bbox": [ + 75, + 90, + 470, + 151 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To address these challenges, we introduce Multimodal alignmEnt aGgregation and distillation (MEGA). MEGA includes a novel module called alignment positional encoding which aligns inputs of variable lengths and different modalities at a coarse temporal level. To fuse the aligned embeddings of different modalities in an efficient and effective manner, we adopt the bottleneck fusion tokens [28] and append a set of fusion tokens to each modality. These tokens share the same sequence length as the normalized positional encoding for different modalities, allowing us to inject them with the coarse temporal information, enabling information fusion in a better aligned embedding space. To address the issue of cross-domain knowledge transfer, we introduce a cross-modal synchronization approach. This method allows us to transfer the manually labeled act boundaries from synopsis level to movie level using rich multimodal information, enabling us to train MEGA directly on videos without relying on screenplay – which was a hard requirement for previous works [30, 32].", + "bbox": [ + 75, + 151, + 473, + 438 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We test our proposed alignment and aggregation modules on the Movienet-318 [18] and the TRIPOD datasets [30], and we test our cross modality synchronization module on TRIPOD alone, as the labels are provided on a different modality during training. Our proposed MEGA outperforms previous SoTA on scene segmentation on the Movienet-318 dataset (by $+1.19\\%$ in AP) and on act segmentation on the TRIPOD dataset (by $+5.51\\%$ in TA). Our contributions are:", + "bbox": [ + 75, + 439, + 470, + 559 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1. Alignment positional encoding module and a fusion bottleneck layer that performs multimodal fusion with aligned multi-modality inputs.", + "2. A cross-domain knowledge transfer module that synchronizes features across-domain, and enables knowledge distillation without requiring extra information.", + "3. SoTA performance on scene and act segmentation tasks, with detailed ablations, which can be used as reference for future work." + ], + "bbox": [ + 89, + 566, + 468, + 699 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 76, + 709, + 218, + 724 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Scene Segmentation in Cinematic Content: Recent works on scene segmentation have explored self-supervised learning (SSL) [8,27,45]. Self-supervised pretext tasks have included maximizing the similarity between nearby shots compared to randomly selected ones [8], maximizing the similarity between pairs of images selected according to scene consistency [45], and maximizing the similarity between pairs of images selected according to pseudo scene boundaries [27]. While several previous works have used multimodal inputs for this task [8,35,45], they have either utilized late fusion of features with predefined weights for each", + "bbox": [ + 75, + 734, + 470, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "modality [35] or have utilized early integration of features derived via SSL [8, 45]. In this paper, we explore how to better align and integrate features from different modalities for scene segmentation.", + "bbox": [ + 496, + 90, + 890, + 151 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Act Segmentation in Cinematic Content: Movie screenplays follow a general narrative structure on how a plot unfolds across the story. Several theories have been proposed in this domain dating as far back as Aristotle, who defined a 3 act structure with a beginning (protasis), middle (epitasis), and end (catastrophe) [33]. Modern screenplays are usually written with a 6 act structure [14], named as \"the setup\", \"the new situation\", \"progress\", \"complications and higher stakes\", \"the final push\", and \"the aftermath\", separated by five turning points (TPs). Prior approaches in narrative segmentation on movies have adopted the aforementioned 6 act structure and posed the problem as identifying the 5 TPs that separate these 6 acts. [32] is to our knowledge the only prior work that utilizes visual domain in act segmentation by using a pre-trained teacher model trained on textual input to train a student Graph Convolutional network with audio-visual-text representations as input. In contrast, our work uses a new multimodal fusion and distillation applied on the modalities which are available with the movie.", + "bbox": [ + 496, + 152, + 893, + 439 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Multimodal Aggregation: Previous SoTAs on multimodal fusion with transformers perform early fusion of the features as inputs to the transformer [19], merge attention between them requiring more memory [9,21], use cross attention between two modalities [9,44], or add cross-modal interactions more efficiently via bottleneck tokens or exchanging some of their latents [15, 28]. [28] provides information flow between modalities efficiently by utilizing bottleneck tokens to tame the quadratic complexity of pairwise attention. This global exchange between modalities may not be enough for long videos, which require an adaptive fusion in different temporal locations. Our model considers [28] as baseline and extends it to incorporate local information during information exchange between modalities.", + "bbox": [ + 496, + 443, + 893, + 654 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Positional Encoding: Previous studies on improving the positional encoding in long sequence modeling have mostly focused on adding relative distance positional encoding [24, 38, 40]. However, they do not offer solutions on better maintaining the relative position of latent tokens with respect to their starting point in time in long sequences with variable lengths, which is important for long movie narrative understanding [5, 14]. We propose Alignment Positional Encoding to bridge this gap.", + "bbox": [ + 496, + 656, + 893, + 792 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Cross-Modality Synchronization & Distillation: To transfer the labels from synopsis to movie shots, we use cross-modality distillation. Previous cross-modality distillation studies for label transfer across modalities are focused on parallel data with the same granularity [2,3,12], or where the alignment is known [31]. Alignment of features at different granularities in the same modality, such as screenplay", + "bbox": [ + 496, + 795, + 893, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "23332", + "bbox": [ + 478, + 944, + 519, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "scenes to synopsis sentences [26, 49] and across modalities such as aligning synopsis sentences to visual shots [42, 47], book chapters to visual scenes [43] have been previously explored. While majority of these works rely on unsupervised optimization techniques [26, 42, 43, 49], there are studies that use supervised labels to improve the representations used for optimization [47]. We present an alignment approach with self-supervised loss for synchronizing data in different modalities of cinematic content to enable distillation.", + "bbox": [ + 75, + 90, + 472, + 224 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Methodology", + "text_level": 1, + "bbox": [ + 76, + 241, + 210, + 258 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "MEGA processes long videos and performs video segmentation in three major steps (Fig. 2). First, a video $V$ is chunked into shots, and multiple features such as scene related features and sound event features are extracted at the shot-level (Sec. 3.1). The system is built on shot-level representation for two reasons: (1) scene and act boundaries always align with shot boundaries, and (2) the content within a shot remains similar, which allows efficient yet meaningful sampling without losing important information. Second, the embeddings from different input samples and each modality are coarsely aligned with a proposed alignment embedding (Sec. 3.2), and the alignment positional tokens are used to refine the commonly used bottleneck fusion tokens for cross-modal feature fusion (Sec. 3.2). Third, a linear layer is applied on top of the fused representations to generate scene and act boundaries (Sec. 3.3). Finally, to address the challenge of cross-domain knowledge transfer where labels from one domain may not directly align with another domain (e.g. act labels on synopsis sentences do not have movie-level timing information), we propose a cross-modal synchronization module that is simple yet effective (Sec. 3.4).", + "bbox": [ + 75, + 267, + 472, + 583 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Preprocessing", + "text_level": 1, + "bbox": [ + 76, + 594, + 220, + 609 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We chose to utilize Transnet-v2 [39] for shot segmentation due to its superior performance and efficiency. We list our selection of pre-trained models and associated parameters in Tab. 1. As each pretrained feature extraction model has different requirements for input resolution and sampling rate, we first sample the input at various sample rates (as shown in Table 1). It is worth noting that the $\\mathrm{CLIP}_{\\mathrm{movie}}$ model is the CLIP [34] model with ViT-B/32 backbone fine-tuned on paired IMDB-image/text dataset. IMDB-image dataset comprises 1.6M images from 31.3K unique movies/TV series with 761 unique textual labels. The features attributed to each shot are the ones with overlap with the shot time stamp (More details are in Appendix). After feature extraction, we aggregate the features for each shot and normalize the feature dimension with linear projection as:", + "bbox": [ + 75, + 617, + 470, + 854 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nE _ {i} ^ {m} = g ^ {m} \\left(\\frac {1}{T _ {i} ^ {m}} \\sum_ {j = 1} ^ {T _ {i} ^ {m}} S _ {i j} ^ {m}\\right) \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 179, + 856, + 468, + 904 + ], + "page_idx": 2 + }, + { + "type": "table", + "img_path": "images/d9f17889695c9ae8dd57891586ec7033d56b223e3bed26ab329ea793531c0cc7.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Feature extractorInput Freq.Input Res.Feature dim.
Visual input
BASSL [27] (bassi)Varying22422048
ResNetPlace [50] (place)1Hz22422048
ResNeXt101 [46] (appr)1Hz22422048
I3D [6] (action)16Hz16 × 22422048
CLIPmovie (clip)1Hz2242768
Acoustic input
PANNs [23] (audio)1Hz10 × 32K2048
Linguistic input
all-MiniLM-L6-v2 [1] (text)Varying-384
", + "bbox": [ + 506, + 88, + 887, + 215 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Table 1: Sampling strategy and feature extraction backbones used for different modalities.", + "bbox": [ + 498, + 227, + 890, + 257 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $E_{i}^{m}\\in \\mathbb{R}^{C}$ denotes the embedding from the $i$ -th shot of $m$ -th modality, $S_{ij}^{m}\\in \\mathbb{R}^{D^{m}}$ is the $j$ -th sampled feature of $m$ -th modality from $i$ -th shot, and $g^{m}$ is a linear projection layer that projects feature dimension for $m$ -th modality to a common dimension $C$ across all modalities.", + "bbox": [ + 496, + 267, + 893, + 342 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "While it is possible to create an end-to-end system starting from raw shot inputs and training the model from scratch, pre-extracting the features from pretrained models is generally more scalable and efficient in actual industrial scenarios, hence we rely on the latter.", + "bbox": [ + 496, + 343, + 893, + 417 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Cross-modality Alignment and Fusion", + "text_level": 1, + "bbox": [ + 500, + 429, + 828, + 445 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "For long video segmentation into scenes and acts it is important to model short and long term context and perform effective multimodal fusion. However, the commonly used learnable positional embedding only provides fine-grained granularity and is not suitable for high-level semantic alignment across modalities. Furthermore, for tasks such as act segmentation we expect consistent patterns at normalized position of temporal inputs as the theory suggests approximate locations for each turning point (i.e., $10\\%$ , $25\\%$ , $50\\%$ , $75\\%$ , $95\\%$ [5, 14, 30]). Hence, in addition to using the traditional positional encoding, we introduce Alignment Positional Encoding layer $\\in \\mathbb{R}^{L_n\\times C}$ , which is a learnable embedding layer, for which the index at $i$ -th temporal unit (e.g., shot) is derived by:", + "bbox": [ + 496, + 453, + 893, + 664 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\ni _ {\\text {a l i g n}} = \\operatorname {f l o o r} \\left(\\frac {L _ {n}}{L} i\\right) \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 617, + 664, + 890, + 698 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $L$ is the temporal dimension (e.g., number of shots) and $L_{n}$ is the length of alignment positional encoding which is a hyper-parameter $(L_{n} < L)$ . We add the alignment positional encoding to the features in conjunction with the conventional positional encoding (see Fig 2). This module is shared across different modalities. This module provides extra information to the network that can be helpful in learning from long training samples with varying lengths, and in coarsely aligning inputs from different modalities before information fusion.", + "bbox": [ + 496, + 704, + 893, + 853 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Inspired by previous works [9, 28, 44], we choose cross-modal feature fusion, which has been shown to be more effective than early or late fusion. To make our approach scale to", + "bbox": [ + 498, + 854, + 893, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "23333", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/b4c1fa0eab68f6677ce713b7eeb86c344366a1b3b7e448da08c09fa934e934a8.jpg", + "image_caption": [ + "Figure 2: The pipeline of the proposed method includes 1) Preprocessing: splitting the video into shots, extraction of features from each shot, pooling and normalization 2) Cross modality fusion and alignment: with the help of alignment positional encoding and bottleneck fusion tokens, 3) Scene/Act Segmentation comprising the segmentation heads. For Scene Segmentation, CE loss is used and for Act Segmentation knowledge transfer loss is used (refer to Sec. 3.4 for details)" + ], + "image_footnote": [], + "bbox": [ + 109, + 88, + 851, + 265 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "multiple modalities, we propose an efficient temporal bottleneck fusion based on [28], and follow their mid-fusion strategy, which comprises of an unimodal transformer encoder followed by a multimodal transformer encoder (See Fig. 2). While [28] proposes to use bottleneck tokens for fusing information across different modalities, these tokens learn to integrate the information across modalities in a global manner. We propose to use $L_{n}$ fusion tokens, and then integrate them with the same Normalized Positional Encoding to align them with features on the coarse temporal scale (Fig. 3).", + "bbox": [ + 75, + 368, + 472, + 518 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The transformer layer per modality then takes in an extra set of aligned fusion tokens concatenated with its input (Fig 2), making it much more efficient compared to other methods such as merged attention or pairwise cross-attention with respect to the number of modalities [9, 21]. Finally, the latent tokens per modality from the last fusion layer (i.e., $Z^{m}$ for m-th modality) are concatenated as the fused representation:", + "bbox": [ + 75, + 520, + 473, + 642 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nZ ^ {\\text {f u s e d}} = \\operatorname {c o n c a t} _ {C} (Z) = \\operatorname {c o n c a t} _ {C} \\left(\\left[ Z ^ {1}, \\dots , Z ^ {M} \\right]\\right) \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 101, + 652, + 470, + 674 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathrm{concat}_C(*)$ stands for channel-wise concatenation and $M$ is the number of modalities.", + "bbox": [ + 75, + 684, + 468, + 715 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Scene/Act Segmentation", + "text_level": 1, + "bbox": [ + 76, + 727, + 299, + 744 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "MEGA adopts a similar approach to previous works [8, 27, 45], where scene segmentation is framed as a binary classification task using a key-shot representation from a window of $2 \\times k + 1$ shots ( $k$ -shots before and after):", + "bbox": [ + 75, + 751, + 470, + 811 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\ny _ {i} = \\varphi \\left(Z _ {i} ^ {\\text {f u s e d}}; \\theta_ {s}\\right) \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 207, + 824, + 468, + 843 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $y_{i}$ is the logit prediction for the $i$ -th key-shot. $\\varphi$ denotes the linear layer with learnable parameters $\\theta_{s}$ and a cross entropy loss is utilized [8, 27, 45].", + "bbox": [ + 75, + 854, + 470, + 902 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/38230f068fb726688e8efa1c12e99c38d33284de129a5743fdc87fdd883bef7d.jpg", + "image_caption": [ + "Figure 3: Illustration of Normalized Positional Encoding integration to the temporal tokens in one modality. This figure shows the integration of normalized Positional Encoding with 1) temporal shots for one modality and 2) bottleneck fusion tokens, where $L = 15$ and $L_{n} = 3$ . For (1) $i_{\\text{align}}$ is obtained per shot index, $i$ , and then each shot is integrated with normalized PE. For (2) each randomly initialized bottleneck token is integrated with normalized PE for its corresponding index." + ], + "image_footnote": [], + "bbox": [ + 527, + 364, + 870, + 523 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The act segmentation task is formulated as $N_{tp}$ linear prediction heads ( $N_{tp}$ is the number of turning points, and $\\theta_{a_n}$ denotes the head parameters for $n$ -th turning point [32]), for each individual shot from a temporal model that takes all the shots of the movie as input. To make a prediction at the $i$ -th shot for the $n$ -th act boundary ( $n \\in \\{1, \\dots, N_{tp}\\}$ ), we use:", + "bbox": [ + 496, + 710, + 893, + 816 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\ny _ {i n} = \\varphi \\left(Z _ {i} ^ {\\text {f u s e d}}; \\theta_ {a _ {n}}\\right) \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 622, + 830, + 892, + 849 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $y_{in}$ is the logit prediction for $i$ -th shot and $n$ -th turning point.", + "bbox": [ + 496, + 869, + 892, + 902 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "23334", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.4. Cross-domain Knowledge Transfer", + "text_level": 1, + "bbox": [ + 76, + 90, + 382, + 107 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "It is quite common during machine learning that certain modalities may lack annotations that are directly available in other modalities with different information granularity. To address this, we propose a cross-modality synchronization scheme that enables cross-modal distillation. We utilize this module for act segmentation where we aim to transfer act labels from synopsis sentences to movie-level timestamps. Importantly, our approach does not require additional information, such as screenplay [32], to bridge the gap.", + "bbox": [ + 75, + 113, + 470, + 250 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Our knowledge distillation utilizes (1) an individual network to learn the synopsis-based act segmentation in a supervised manner with cross-entropy loss similar to [31]; and (2) a novel synchronization approach between synopsis and movie. For (1) we use the same architecture mentioned in Secs. 3.1, 3.2, setting $C_{\\mathrm{fused}}$ equal to the multimodal shot model setting. Additionally, similar to shot level linear prediction head (See Eq. 5), we use a sentence level linear prediction head, resulting in $q_{in}$ logits for the $i$ -th sentence of $n$ -th TP. A supervised Cross Entropy loss is used to learn the synopsis labels from predictions for each turning point $(\\mathcal{L}_{ce})$ . For (2) we seek a synchronization matrix $W \\in \\mathbb{R}^{L_{sh} \\times L_{syn}}$ between $L_{sh}$ shots and $L_{syn}$ synopsis sentences for a sample, where $w_{ij} = 1$ if the $i$ -th shot matches with the $j$ -th synopsis sentence and $w_{ij} = 0$ , otherwise. Assuming $F(:, \\theta)$ represents a parametric reward function (with parameters $\\theta$ ), to find $W$ , we define an objective as:", + "bbox": [ + 75, + 250, + 473, + 507 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\max _ {W, \\theta} \\sum_ {i, j} w _ {i j} F (.; \\theta) - \\lambda \\sum_ {i, j} | w _ {i, j} | \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 158, + 518, + 468, + 551 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\ns. t. 0 \\leq w _ {i j} \\leq 1\n$$\n", + "text_format": "latex", + "bbox": [ + 217, + 555, + 331, + 571 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Expectation-Maximization algorithm is used to solve the objective in Eq. 6. We estimate the target variable $W$ via fixed parameters (i.e., $\\theta$ ) in the E-step, and update the parameters while the target variable is known in the M-step.", + "bbox": [ + 75, + 583, + 468, + 643 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "E-step: Assuming $F(:,\\theta)$ returns the similarity of input shot and synopsis sentence pair, the E-step has a closed form solution. In the E-step, following [26], we reduce the search space during optimization to only the pairs which are inside a diagonal boundary (see the proof for E-step and visualization of expected synchronization matrix for different examples in Appendix).", + "bbox": [ + 75, + 643, + 468, + 748 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "M-step: Using all samples in a batch with $L_{\\mathrm{SH}}$ , $L_{\\mathrm{SYN}}$ total number of shots and synopsis sentences, we form their cosine similarity matrix of dimension $L_{\\mathrm{SH}} \\times L_{\\mathrm{SYN}}$ . For each query (synopsis sentence/movie shot, respectively), the positive keys (movie shot/synopsis sentence, respectively) are derived from the expectation step. Negative keys are the keys lying outside the diagonal boundary of the similarity matrix of shot-synopsis pairs for one movie [26], and all the keys from other movies within the batch. Here each query (synopsis sentence/movie shot, respectively) can have more than one", + "bbox": [ + 75, + 750, + 470, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "positive key (movie shot/synopsis sentence, respectively) attached to it. Following [20], we adopt a modified version of the InfoNCE loss and combine it with the symmetric contrastive loss [34] as:", + "bbox": [ + 496, + 90, + 892, + 151 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {L} _ {c} = - \\sum_ {i = 1} ^ {L _ {\\mathrm {S Y N}}} \\frac {1}{| \\hat {y} _ {i} |} \\sum_ {k = 1} ^ {L _ {\\mathrm {S H}}} \\hat {y} _ {i k} \\log \\frac {\\exp \\left(v _ {i} u _ {k} / \\tau\\right)}{\\sum_ {j = 1} ^ {L _ {\\mathrm {S H}}} \\exp \\left(v _ {i} u _ {j} / \\tau\\right)} - \\tag {7} \\\\ \\sum_ {i = 1} ^ {L _ {\\mathrm {S H}}} \\frac {1}{| \\hat {y} _ {i} ^ {T} |} \\sum_ {k = 1} ^ {L _ {\\mathrm {S Y N}}} \\hat {y} _ {i k} ^ {T} \\log \\frac {e x p (u _ {i} v _ {k} / \\tau)}{\\sum_ {j = 1} ^ {L _ {\\mathrm {S Y N}}} e x p (u _ {i} v _ {j} / \\tau)} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 514, + 161, + 892, + 250 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\tau$ is a learnable temperature parameter, and $\\hat{y}_{ij}$ is a binary indicator of positive vs. negative pairs, $u_{i}$ is the normalized feature for the $i$ -th shot and $v_{i}$ is the normalized feature for the $i$ -th synopsis sentence.", + "bbox": [ + 496, + 257, + 892, + 316 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Knowledge distillation: Knowledge distillation is used to transfer the knowledge available for the training samples on synopsis. The predictions from the synopsis model are mapped to shots using a matrix of their similarities as calculated in the maximization step, for each sample. The similarity scores for each shot are normalized along the synopsis sentences with softmax. The logit predictions from synopsis model are transferred to shots by multiplication with the normalized similarity matrix. A softmax along the shots is applied to the transferred logits to derive the probability scores for each shot. Following [31], we use a Kullback-Leibler divergence loss between predicted outputs for each shot and the transferred probabilities $(\\mathcal{L}_{kd})$ (More details are provided in Appendix.).", + "bbox": [ + 496, + 316, + 893, + 527 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The cross-domain knowledge transfer module can be trained by simply adding the losses together as:", + "bbox": [ + 498, + 529, + 892, + 559 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} = \\alpha_ {c} \\mathcal {L} _ {c} + \\alpha_ {c e} \\mathcal {L} _ {c e} + \\alpha_ {k d} \\mathcal {L} _ {k d} \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 581, + 570, + 890, + 585 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\alpha_{c},\\alpha_{ce}$ , and $\\alpha_{kd}$ are hyperparameters that control the weights of the three losses.", + "bbox": [ + 496, + 598, + 890, + 628 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 500, + 641, + 633, + 657 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Dataset", + "text_level": 1, + "bbox": [ + 500, + 666, + 594, + 680 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We test our model on two commonly used dataset: Movienet-318 [18]: consists of 1100 movies, out of which 318 movies are annotated for the task of scene segmentation. The annotated dataset is split into 190, 64, and 64 movies for train, validation and test splits, respectively. We report the Average Precision (AP) and F1-score (F1) on the test split following previous work [35, 45].", + "bbox": [ + 496, + 689, + 893, + 794 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "TRIPOD [32] includes 122 movies, split into 84, and 38 movies for train and test, respectively. This dataset includes the annotations of 6 act boundaries (\"the setup\", \"the new situation\", \"progress\", \"complications and higher stakes\", \"the final push\", \"the aftermath\") on the movie synopsis sentences for the training set, and on the movie screenplay scenes for the test set. The authors also have released soft", + "bbox": [ + 496, + 794, + 893, + 898 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "23335", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "probability scores (silver annotations) for the training set, using $[30]^1$ . To find the timestamps for the screenplay scenes in the movie, following [32] we used Dynamic Time Warping (DTW) to align the timed subtitles from the movie to the monologue lines in the screenplay. Following [32], we use total agreement (TA), partial agreement (PA) and distance (D) as evaluation metrics.", + "bbox": [ + 75, + 90, + 472, + 196 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Implementation Details", + "text_level": 1, + "bbox": [ + 76, + 205, + 294, + 220 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "For scene segmentation: We train our model with 8 V100 GPUs with total batch size of 1024. The Adam [22] optimizer is used with learning rate of 1e-4. We train the model for 20 epochs. GeLU [16] is used as activation function by default, we use weighted cross entropy to balance the positive and negative samples at batch level. We choose shot sequence length of $17(k = 8)$ following [27]. We set $L_{n} = 2$ for this model.", + "bbox": [ + 75, + 227, + 470, + 348 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "For act segmentation: We train our model with 4 V100 GPUs with total batch size of 4. The SGD optimizer is used with learning rate of 1e-3. We train the model for 10 epochs. $\\lambda$ in Eq. 6 is empirically set differently for each synopsis sentence of each sample, by finding $99\\%$ percentile of the similarity scores between the synopsis sentence and all the shots corresponding to that sample. $\\alpha_{c}, \\alpha_{ce}, \\alpha_{kd}$ are set to 1, 1, and 10. We set $L_{n} = 100$ for this the shot model and $L_{n} = 20$ for the synopsis model. We use max pooling to aggregate the shot-level predictions to scene level. We use all shots from a video for act segmentation.", + "bbox": [ + 75, + 349, + 472, + 515 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Main Results", + "text_level": 1, + "bbox": [ + 76, + 523, + 217, + 537 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "SoTA on Scene Segmentation. We first show MEGA outperforms previous SoTA on MovieNet318 [27] for scene segmentation $(+1.19\\%)$ on AP and $+8.28\\%$ on F1). With the same input visual features, MEGA outperforms previous SoTA [27] (Tab. $2 + 0.52\\%$ on AP and $+3.69\\%$ on F1), which indicates that the proposed approach is effective. Thanks to the proposed cross-modality fusion module, the MEGA generalizes and benefits from additional information extracted from visual signals. MEGA with 3 visual modalities (clip, place, and bassl) outperforms single modality model by $+0.67\\%$ on AP and $+4.59\\%$ on F1, which shows the proposed fusion works as expected. It is worth mentioning that the proposed method is scalable and generalizes to various number of modalities at different scales, which makes it flexible for real-world applications.", + "bbox": [ + 75, + 546, + 472, + 772 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "SoTA on Act Segmentation. We then show that MEGA establishes the new SoTA performance on act segmentation on TRIPOD dataset (Tab. 3). We first show that MEGA outperforms previous SoTA on TRIPOD [32] dataset With only visual signals as input. Comparing to other works that take textural inputs [29, 32], MEGA is able to achieve better performance. Furthermore, in real-world applications, the", + "bbox": [ + 75, + 773, + 470, + 878 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/a7e5296b2fdb582714b90b74c76231d55e82aead0917f1cb90dda76fe70d2c29.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ApproachModalityPretrained onAP↑ [%]FI↑ [%]
Random [35]--8.2-
Visual only input
GraphCut [36]VPlaces [50]14.1-
SCSA [7]VPlaces [50]14.7-
DP [13]VPlaces [50]15.5-
Grouping [37]VPlaces [50]17.6-
StoryGraph [41]VPlaces [50]25.1-
Siamese [4]VPlaces [50]28.1-
LGSS [35]VPlaces [35]39.0-
LGSS [35]VCast [17,48]15.9-
LGSS [35]VAction [11]32.1-
ShotCoL [8]†VMovienet [18]52.8949.17
SCRL [45]VMovienet [18]54.8251.43
BaSSL [27]VMovienet [18]57.447.02
MEGAVMovienet [18]57.9250.71
MEGAVM+P+I58.5955.30
", + "bbox": [ + 517, + 88, + 875, + 301 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2: Scene boundary detection: comparison with SoTA. $\\dagger$ means the numbers are copied from [45]. M+P+I denotes pre-trained on Movienet [18], Places [50] and IMDB.", + "bbox": [ + 496, + 308, + 893, + 354 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "visual input (the video) is often easier to obtain than textual inputs such as screenplay [32]. We further show that MEGA* (Tab. 3), which swaps our synchronization module to use similar synchronization as SoTA [32], outperforms GRAPHTP, which demonstrates the effectiveness of proposed approach including the alignment and fusion modules. It is worth mentioning that, with multiple features extracted from visual media modality alone, MEGA outperforms previous SOTA which makes the proposed model applicable for real-world scenarios, as it is usually harder to get additional media modalities (e.g., screenplay) which are used in other works.", + "bbox": [ + 496, + 367, + 893, + 547 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "By further aggregating the results from text input, MEGA establishes the new state-of-the-art on TRIPOD dataset (Tab. 3). MEGA almost doubles the performance of previous work [29, 32] with $+5.51\\%$ TA, $+9.15\\%$ PA, $-\\%0.81$ D. This shows the proposed multimodal fusion scales and generalizes well to multiple modalities. The cross-modality distillation also works robustly for various settings. We noticed that adding the acoustic features is not always helpful to the performance (Tab. 3), probably because acoustic information provides redundant or not useful information for the task of act boundary segmentation.", + "bbox": [ + 496, + 549, + 895, + 715 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.4. Ablations", + "text_level": 1, + "bbox": [ + 500, + 724, + 611, + 739 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We perform ablations to examine the effectiveness of major building blocks of MEGA. We use features extracted from visual media modality (for scene segmentation: clip, place, Bassl and for act segmentation: clip, appr, action, place), with the proposed normalized positional encoding, multi-modality bottleneck fusion, and cross-modality synchronization by default unless specified. The training and evaluation follows same protocols as mentioned in Sec. 4.3. Alignment Positional Encoding. We report the ablations on Alignment PE in Tab. 4a. We notice that the proposed", + "bbox": [ + 496, + 750, + 893, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_footnote", + "text": "1https://github.com/ppapalampidi/GraphTP", + "bbox": [ + 94, + 886, + 410, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "23336", + "bbox": [ + 478, + 945, + 519, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/c1aed1c7f72e851cd75da5b3fd8eda56b55ae3a9b0f9089d95856705e232e2e5.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ApproachModalityModality for synch.TA↑ [%]PA↑ [%]D↓ [%]
Random (Evenly dist.) [32]-T*4.826.9512.35
Theory [14, 30]-T*4.416.3211.03
Distribution position [32]-T*5.597.3710.74
Single modality input
TEXTRANK [25]T*T*6.1810.0017.77
SCENESUM [10]T*T*4.417.8916.86
TAM [29]T*T*7.949.479.42
GRAPHTP [32]T*T*6.7610.009.62
MEGA*VT*10.5114.548.98
MEGAVV13.9320.729.19
Multi-modality input
TEXTRANK [25]T*+A+VT*6.1810.0018.90
SCENESUM [10]T*+A+VT*6.7611.0518.93
TAM [29]T*+A+VT*7.3610.0010.01
GRAPHTP [32]T*+A+VT*9.1212.639.77
MEGA*T+VT*11.1415.208.96
MEGAT+VT+V14.6321.788.96
MEGA*T+A+VT*10.0014.088.96
MEGAT+A+VT+A+V14.1922.109.68
", + "bbox": [ + 81, + 87, + 480, + 325 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "alignment PE consistently improves the performance on both scene and act segmentation tasks, while act segmentation benefits more significantly from it. This is because of two reasons: 1) inputs to the act segmentation model have variable lengths (all the shots from a video) as opposed to scene segmentation which has fixed length inputs, hence the alignment PE adds more information to the act segmentation model; and 2) Alignment PE is shared across all modalities and fusion layer and its absence causes more harm to sequences with longer lengths, as act segmentation takes longer shot sequences (entire video) compared to scene segmentation (17 shots). Overall, the drop in performance indicates that the proposed Alignment P.E. is an essential component for video segmentation tasks.", + "bbox": [ + 75, + 410, + 468, + 621 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We further remove the proposed Alignment PE from bottleneck fusion tokens and show results in Tab. 4b. We observe a performance drop when removing the Alignment PE. It is worth mentioning that the performance drop is more noticeable when multiple modalities are involved, (e.g. V + T model), which suggests that the information from subtitles requires precise temporal alignment in order to be effective during multimodal fusion.", + "bbox": [ + 75, + 623, + 468, + 744 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Multimodal Fusion Strategies. Tab. 4c compares our proposed fusion tokens with the commonly used late fusion strategy. The results show that the temporal bottleneck fusion clearly outperforms late fusion, demonstrating the effectiveness of aligned bottleneck tokens in improving the performance across both tasks.", + "bbox": [ + 75, + 747, + 470, + 838 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Different Input Modalities. We study the impact of different modalities by removing them from the input and present results on scene segmentation and act segmentation. In scene segmentation (Tab. 4d), we find that the Bassl feature fol", + "bbox": [ + 75, + 839, + 472, + 901 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/05bcf01fec3972f025ce50ea948ebdf6a9e75feaaa57f485de8857fe122aae4b.jpg", + "table_caption": [ + "Table 3: TP identification: comparison with SoTA. MEGA* denotes the MEGA using the same synchronization as [30] for fair comparison. T*,V,T,A denote Textual-screenplay, Visual, Textual-subtitle and Acoustic features, respectively." + ], + "table_footnote": [], + "table_body": "
caseScene Seg.Act Segmentation
AP↑TA↑PA↑D↓
w/o align. PE57.775.297.3731.04
w. align. PE58.5913.9320.729.19
", + "bbox": [ + 511, + 88, + 880, + 157 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/28345670680c5cf75fca43424e29c82edd53847a61eb45440e65b24d2523e422.jpg", + "table_caption": [ + "(a) Effectiveness of Alignment Positional Encoding." + ], + "table_footnote": [], + "table_body": "
casemodalityScene Seg.Act Segmentation
AP↑TA↑PA↑D↓
w/o align.PEV58.3113.6020.539.47
w. align.PEV58.5913.9320.729.19
w/o align.PEV + T-13.0120.139.56
w. align.PEV + T-14.6321.788.96
", + "bbox": [ + 511, + 186, + 880, + 281 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/d75349a0e3b86b6a63f1c60b3ad16a0a559b636b34cc52836cc5c8fd0e88c650.jpg", + "table_caption": [ + "(b) Effectiveness of Normalized Positional Encoding in bottleneck tokens." + ], + "table_footnote": [], + "table_body": "
MM. integ. typeScene Seg.Act Segmentation
AP↑TA↑PA↑D↓
LateFusion58.2412.5719.2110.00
Bottleneck58.5913.9320.729.19
", + "bbox": [ + 514, + 309, + 877, + 378 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/d1c20b98b9e98e1c850799d1d6d5bcbce4dab6f81d9ec84c37b8be02515d9cce.jpg", + "table_caption": [ + "(c) Multi-modal fusion strategies." + ], + "table_footnote": [], + "table_body": "
changeAP↑
-clip58.09
-place57.51
-bassl51.88
-clip-place57.92
-58.59
", + "bbox": [ + 506, + 407, + 629, + 498 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/2a7945fc8f16976c443874bb23b25f5d708ae9cc2c2ca685f7ed1cc1c17d0985.jpg", + "table_caption": [ + "(d) Impact from input modalities on scene seg." + ], + "table_footnote": [], + "table_body": "
changeTA↑PA↑D↓
-clip6.0910.6621.81
-place13.5719.879.22
-action13.3120.2010.38
-appr13.4220.598.85
-13.9320.729.19
+subtitle14.6321.788.96
", + "bbox": [ + 689, + 407, + 885, + 498 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/644c0ce660192368bb48e71aac304b5025c263f1b21c1a84c4b90ee244f6484c.jpg", + "table_caption": [ + "(e) Impact from input modalities on act segmentation." + ], + "table_footnote": [], + "table_body": "
synopsis synch. byM for synch.TA↑PA↑D↓
[30]T*10.5114.548.98
MEGAV13.9320.729.19
MEGAV + T14.6321.788.96
", + "bbox": [ + 519, + 537, + 874, + 603 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/0ba289f1200482b90d3197b98ce2f05143e8dafcbec12bacf67dc207920eab1a.jpg", + "table_caption": [ + "(f) Impact of Synchronization with multimodal video features on act segmentation." + ], + "table_footnote": [], + "table_body": "
ApproachFeature Set Pretrained onAP↑Params↓SPS↑
BaSSL [27]Movienet57.415.77M6244.99
LGSS [35]M+P+I52.9366.16M206.36
MEGAM+P+I58.5967.57M1736.13
", + "bbox": [ + 506, + 643, + 890, + 700 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/a2065619740587798ecfc8464a7b686a81c1d6d8467fbbaf371e284134e23408.jpg", + "table_caption": [ + "(g) Impact from feature set and model size on scene seg. SPS denotes # of samples per second." + ], + "table_footnote": [], + "table_body": "
ApproachFeature SetTA↑PA↑D↓Params↓SPS↑
GRAPHTP [32]Set1 [32]9.1212.639.770.745M25.40
GRAPHTP [32]Set24.727.379.696.78M14.36
MEGASet214.1922.109.686.78M18.24
", + "bbox": [ + 506, + 741, + 895, + 797 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "(h) Impact from feature set and model size on act seg. Set1 includes Visual (appr), Audio (YAMNet), Textual (script-USE). Set2 has Visual (appr,clip,action.place), Audio (audio), Textual (text from subtitle).", + "bbox": [ + 500, + 803, + 895, + 840 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 4: Ablation studies on MEGA components.", + "bbox": [ + 529, + 842, + 857, + 857 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "lowed by place are the most important. This is because the BaSSL [27] model is pretrained for scene segmenta-", + "bbox": [ + 500, + 869, + 893, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "23337", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "tion and place consistency is critical for scene segmentation. In act segmentation (Tab. 4e), we find that the CLIP feature pre-trained on IMDB, followed by subtitle are the most important features. This is because the clip model is pre-trained on abstract concepts (e.g. genre, micro genre, character type and coarse key places), thus the CLIP feature contains richer semantics, and subtitle provides complementary rich semantic information. These high level semantics are considered useful for act segmentation. Overall, when all the features are included, the model is able to leverage the unique information provided by each feature and yields the best performance.", + "bbox": [ + 75, + 90, + 472, + 271 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Cross-modality Synchronization. Tab. 4f studies the effectiveness of the proposed cross modality synchronization on act segmentation. To establish a baseline, we use the probability scores provided by [32] and derived by aligning synopsis sentences to scenes using screenplay [30] (T* in Tab. 4f denotes screenplay). For a fair comparison, we repeat the scores provided for each scene on all of its shots and then re-normalize2. MEGA with visual only input outperforms [30] across two metrics (PA and TA) and when we add the subtitle features (T in Tab. 4f denotes subtitle), MEGA outperforms [30] across all the metrics. The results demonstrate that the proposed cross-domain synchronization works effectively and generalize well to various modalities. It is worth mentioning that the proposed method generates act segmentation without requiring the screenplay, which makes it practical for various industrial applications.", + "bbox": [ + 75, + 273, + 472, + 515 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Impact of Feature Set. In Tab. 4g, we examine whether feature set plays an outsized role in MEGA's improved performance over other methods. On the same feature set of $\\mathrm{M} + \\mathrm{P} + \\mathrm{I}$ , we outperform LGSS [35] while only introducing a small number of additional parameters. BaSSL [27] achieves slightly lower performance using only Movienet features, indicating that the use of additional features is not the primary reason for our improved performance.", + "bbox": [ + 75, + 515, + 472, + 636 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Impact of Model Size. We finally look into the impact of model size on the performance. To establish the fair comparison, we first expand GRAPHTP [32] which shares the same input as MEGA to roughly the same number of parameters as MEGA. Our results on act segmentation (Tab. 4h) show that MEGA outperforms the previous SoTA, GRAPHTP [32], which indicates the MEGA has efficient and effective design.", + "bbox": [ + 75, + 637, + 472, + 743 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.5. Fusion with Audio Modality", + "text_level": 1, + "bbox": [ + 76, + 753, + 328, + 768 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We also experimented with the effect of adding audio. Movienet [18] has released Short Time Fourier Transform (STFT) features extracted from audio files. We use the same audio backbone as [35]. However, by adding audio features", + "bbox": [ + 75, + 777, + 470, + 839 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/8941c641ad24748221db938432dc0d1c6a0b36306d6331e7d06a22cc695f815a.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ApproachModalityAP↑ [%]
LGSS [35]V(place)39.00
ShotCoL [8];V46.77
SCRL [45]V54.55
MEGAV(place,clip,bassl)58.59
LGSS [35]V(place)+A43.4
ShotCoL [8];V+A44.32
SCRL [45]V+A50.80
MEGAV(place,clip,bassl)+A55.36
", + "bbox": [ + 549, + 87, + 874, + 229 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 5: Scene Seg. with audio. $\\ddagger$ denotes copying from [45].", + "bbox": [ + 498, + 239, + 890, + 255 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "in MEGA, we see a drop in the performance (see Tab. 5). Although [8, 35] have shown improvements across multiple models by adding the audio modality across Movienet-150 dataset [35] (where the split is not publicly available) or a private dataset: AdCuepoints [8], Wu et al. [45] have observed a similar trend as our experiments, where adding the released audio features in Movienet [18] to SCRL [45] and ShotCoL [8] drops the performance (see Tab. 5). Possible reasons can be 1) the audio features published by Movienet via STFT $^3$ are an incomplete view of the shot from audio modality either in representation or in terms of the audio chunk from each shot they used, and the raw audio files are not available. 2) our multimodal fusion strategy cannot exploit the possible complementary information or filter the harmful or confusing signals from the audio modality.", + "bbox": [ + 496, + 263, + 893, + 492 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Discussion and Conclusion", + "text_level": 1, + "bbox": [ + 498, + 503, + 750, + 518 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Limitations. The explorations in this work are limited to appearance, location, activity, acoustic and textual features. For long movie segmentation, however, providing the name of actors (tabular data) and having a specific component for actor identification in the movie can help both the synchronization and the act/scene segmentation models. We will explore the use of this data.", + "bbox": [ + 496, + 529, + 893, + 633 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "The results demonstrated that richer semantic representations from the clip features enhanced the performance for long video segmentation. To obtain better performing representations for long video understanding one can use large amount of unlabeled data with carefully selected pretext tasks for understanding long context. We will investigate the use of SSL to train a rich multimodal representation from videos and will examine the learned representations across multiple long video understanding tasks.", + "bbox": [ + 496, + 635, + 893, + 771 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Conclusion. This paper introduces MEGA, a unified solution for long video segmentation. Our design of normalized positional encoding, and their integration into fusion tokens allows MEGA to learn consistent patterns from inputs with variable lengths and efficiently and effectively align and fuse them across different modalities. Our synchronization schema further allows the use of rich multimodal tokens to", + "bbox": [ + 496, + 771, + 893, + 878 + ], + "page_idx": 7 + }, + { + "type": "page_footnote", + "text": "2This strategy maintains the rank of probability scores for different turning points across different segments of the movie, and is consistent with the max-pooling of prediction scores on shot level to derive the scene level predictions during evaluation (see Sec. 4.2).", + "bbox": [ + 75, + 849, + 470, + 901 + ], + "page_idx": 7 + }, + { + "type": "page_footnote", + "text": "3https://github.com/movienet/movienet-tools", + "bbox": [ + 514, + 886, + 857, + 898 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "23338", + "bbox": [ + 478, + 944, + 519, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "be used in transferring the labels from synopsis sentences to movie shots, facilitating the knowledge distillation from synopses to movies. MEGA achieves state-of-the-art performance compared with previous works.", + "bbox": [ + 76, + 90, + 472, + 151 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 162, + 171, + 178 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Sentence-transformers model: all-minilm-l6-v2 from Hugging Face. https://huggingface.co/sentence-transformers/all-MiniLM-L6-v2.3", + "[2] Yuki Asano, Mandela Patrick, Christian Rupprecht, and Andrea Vedaldi. Labelling unlabelled videos from scratch with multi-modal self-supervision. Advances in Neural Information Processing Systems, 33:4660-4671, 2020. 2", + "[3] Yusuf Aytar, Carl Vondrick, and Antonio Torralba. Soundnet: Learning sound representations from unlabeled video. Advances in neural information processing systems, 29, 2016. 2", + "[4] Lorenzo Baraldi, Costantino Grana, and Rita Cucchiara. A deep siamese network for scene detection in broadcast videos. In Proceedings of the 23rd ACM international conference on Multimedia, pages 1199-1202, 2015. 6", + "[5] Jessica Brody. Save the Cat! Writes a Novel: The Last Book On Novel Writing You'll Ever Need. Ten Speed Press, 2018. 2, 3", + "[6] Joao Carreira and Andrew Zisserman. Quo vadis, action recognition? a new model and the kinetics dataset. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 6299-6308, 2017. 3", + "[7] Vasileios T Chasanis, Aristidis C Likas, and Nikolaos P Galatsanos. Scene detection in videos using shot clustering and sequence alignment. IEEE transactions on multimedia, 11(1):89-100, 2008. 6", + "[8] Shixing Chen, Xiaohan Nie, David Fan, Dongqing Zhang, Visual Bhat, and Raffay Hamid. Shot contrastive self-supervised learning for scene boundary detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9796-9805, 2021. 1, 2, 4, 6, 8", + "[9] Zi-Yi Dou, Yichong Xu, Zhe Gan, Jianfeng Wang, Shuohang Wang, Lijuan Wang, Chenguang Zhu, Pengchuan Zhang, Lu Yuan, Nanyun Peng, et al. An empirical study of training end-to-end vision-and-language transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18166-18176, 2022. 1, 2, 3, 4", + "[10] Philip Gorinski and Mirella Lapata. Movie script summarization as graph-based scene extraction. In Proceedings of the 2015 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pages 1066-1076, 2015. 7", + "[11] Chunhui Gu, Chen Sun, David A Ross, Carl Vondrick, Caroline Pantofaru, Yeqing Li, Sudheendra Vijayanarasimhan, George Toderici, Susanna Ricco, Rahul Sukthankar, et al. Ava: A video dataset of spatio-temporally localized atomic visual actions. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 6047-6056, 2018. 6", + "[12] Saurabh Gupta, Judy Hoffman, and Jitendra Malik. Cross modal distillation for supervision transfer. In Proceedings of" + ], + "bbox": [ + 78, + 188, + 470, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "the IEEE conference on computer vision and pattern recognition, pages 2827-2836, 2016. 2", + "[13] Bo Han and Weiguo Wu. Video scene segmentation using a novel boundary evaluation criterion and dynamic programming. In 2011 IEEE International conference on multimedia and expo, pages 1-6. IEEE, 2011. 6", + "[14] Michael Hauge. Storytelling Made Easy: Persuade and Transform Your Audiences, Buyers, And Clients-Simply, Quickly, and Profitably. BookBaby, 2017. 1, 2, 3, 7", + "[15] Lisa Anne Hendricks, John Mellor, Rosalia Schneider, Jean-Baptiste Alayrac, and Aida Nematzadeh. Decoupling the role of data, attention, and losses in multimodal transformers. Transactions of the Association for Computational Linguistics, 9:570-585, 2021. 2", + "[16] Dan Hendrycks and Kevin Gimpel. Gaussian error linear units (gelus). arXiv preprint arXiv:1606.08415, 2016. 6", + "[17] Qingqiu Huang, Yu Xiong, and Dahua Lin. Unifying identification and context learning for person recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 2217-2225, 2018. 6", + "[18] Qingqiu Huang, Yu Xiong, Anyi Rao, Jiaze Wang, and Dahua Lin. Movienet: A holistic dataset for movie understanding. In European Conference on Computer Vision, pages 709-727. Springer, 2020. 2, 5, 6, 8", + "[19] Andrew Jaegle, Felix Gimeno, Andy Brock, Oriol Vinyals, Andrew Zisserman, and Joao Carreira. Perceiver: General perception with iterative attention. In International conference on machine learning, pages 4651-4664. PMLR, 2021. 2", + "[20] Prannay Khosla, Piotr Teterwak, Chen Wang, Aaron Sarna, Yonglong Tian, Phillip Isola, Aaron Maschinot, Ce Liu, and Dilip Krishnan. Supervised contrastive learning. Advances in Neural Information Processing Systems, 33:18661-18673, 2020. 5", + "[21] Wonjae Kim, Bokyung Son, and Ildoo Kim. Vilt: Vision-and-language transformer without convolution or region supervision. In International Conference on Machine Learning, pages 5583-5594. PMLR, 2021. 1, 2, 4", + "[22] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. 6", + "[23] Qiuqiang Kong, Yin Cao, Turab Iqbal, Yuxuan Wang, Wenwu Wang, and Mark D Plumbley. Panns: Large-scale pretrained audio neural networks for audio pattern recognition. IEEE/ACM Transactions on Audio, Speech, and Language Processing, 28:2880-2894, 2020. 3", + "[24] Shengjie Luo, Shanda Li, Tianle Cai, Di He, Dinglan Peng, Shuxin Zheng, Guolin Ke, Liwei Wang, and Tie-Yan Liu. Stable, fast and accurate: Kernelized attention with relative positional encoding. Advances in Neural Information Processing Systems, 34:22795-22807, 2021. 2", + "[25] Rada Mihalcea and Paul Tarau. Textrank: Bringing order into text. In Proceedings of the 2004 conference on empirical methods in natural language processing, pages 404-411, 2004. 7", + "[26] Paramita Mirza, Mostafa Abouhamra, and Gerhard Weikum. Alignnarr: Aligning narratives on movies. In The 59th Annual" + ], + "bbox": [ + 503, + 92, + 893, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "23339", + "bbox": [ + 478, + 945, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing, pages 427-433. ACL, 2021. 3, 5", + "[27] Jonghwan Mun, Minchul Shin, Gunsoo Han, Sangho Lee, Seongsu Ha, Joonseok Lee, and Eun-Sol Kim. Boundary-aware self-supervised learning for video scene segmentation. arXiv preprint arXiv:2201.05277, 2022. 2, 3, 4, 6, 7, 8", + "[28] Arsha Nagrani, Shan Yang, Anurag Arnab, Aren Jansen, Cordelia Schmid, and Chen Sun. Attention bottlenecks for multimodal fusion. Advances in Neural Information Processing Systems, 34:14200-14213, 2021. 2, 3, 4", + "[29] Pinelopi Papalampidi, Frank Keller, Lea Frermann, and Mirella Lapata. Screenplay summarization using latent narrative structure. In Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics, pages 1920-1933, 2020. 6, 7", + "[30] Pinelopi Papalampidi, Frank Keller, and Mirella Lapata. Movie plot analysis via turning point identification. arXiv preprint arXiv:1908.10328, 2019. 1, 2, 3, 6, 7, 8", + "[31] Pinelopi Papalampidi, Frank Keller, and Mirella Lapata. Film trailer generation via task decomposition. arXiv preprint arXiv:2111.08774, 2021. 2, 5", + "[32] Pinelopi Papalampidi, Frank Keller, and Mirella Lapata. Movie summarization via sparse graph construction. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 13631-13639, 2021. 1, 2, 4, 5, 6, 7, 8", + "[33] Patrice Pavis. Dictionary of the theatre: Terms, concepts, and analysis. University of Toronto Press, 1998. 2", + "[34] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning, pages 8748-8763. PMLR, 2021. 3, 5", + "[35] Anyi Rao, Linning Xu, Yu Xiong, Guodong Xu, Qingqiu Huang, Bolei Zhou, and Dahua Lin. A local-to-global approach to multi-modal movie scene segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10146-10155, 2020. 1, 2, 5, 6, 7, 8", + "[36] Zeeshan Rasheed and Mubarak Shah. Detection and representation of scenes in videos. IEEE transactions on Multimedia, 7(6):1097-1105, 2005. 6", + "[37] Daniel Rotman, Dror Porat, and Gal Ashour. Optimal sequential grouping for robust video scene detection using multiple modalities. International Journal of Semantic Computing, 11(02):193-208, 2017. 6", + "[38] Peter Shaw, Jakob Uszkoreit, and Ashish Vaswani. Self-attention with relative position representations. In Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 2 (Short Papers), pages 464–468, 2018. 2", + "[39] Tomáš Souček and Jakub Lokoc. Transnet v2: an effective deep network architecture for fast shot transition detection. arXiv preprint arXiv:2008.04838, 2020. 1, 3" + ], + "bbox": [ + 78, + 90, + 470, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[40] Jianlin Su, Yu Lu, Shengfeng Pan, Bo Wen, and Yunfeng Liu. Roformer: Enhanced transformer with rotary position embedding. arXiv preprint arXiv:2104.09864, 2021. 2", + "[41] Makarand Tapaswi, Martin Bauml, and Rainer Stiefelhagen. Storygraphs: visualizing character interactions as a timeline. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 827-834, 2014. 6", + "[42] Makarand Tapaswi, Martin Bäuml, and Rainer Stiefelhagen. Aligning plot synopses to videos for story-based retrieval. International Journal of Multimedia Information Retrieval, 4(1):3-16, 2015. 3", + "[43] Makarand Tapaswi, Martin Bauml, and Rainer Stiefelhagen. Book2movie: Aligning video scenes with book chapters. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1827-1835, 2015. 3", + "[44] Yikai Wang, Wenbing Huang, Fuchun Sun, Tingyang Xu, Yu Rong, and Junzhou Huang. Deep multimodal fusion by channel exchanging. Advances in Neural Information Processing Systems, 33:4835-4845, 2020. 2, 3", + "[45] Haoqian Wu, Keyu Chen, Yanan Luo, Ruizhi Qiao, Bo Ren, Haozhe Liu, Weicheng Xie, and Linlin Shen. Scene consistency representation learning for video scene segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14021-14030, 2022. 2, 4, 5, 6, 8", + "[46] Saining Xie, Ross Girshick, Piotr Dólar, Zhuowen Tu, and Kaiming He. Aggregated residual transformations for deep neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1492-1500, 2017. 3", + "[47] Yu Xiong, Qingquiu Huang, Lingfeng Guo, Hang Zhou, Bolei Zhou, and Dahua Lin. A graph-based framework to bridge movies and synopses. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4592-4601, 2019. 3", + "[48] Ning Zhang, Manohar Paluri, Yaniv Taigman, Rob Fergus, and Lubomir Bourdev. Beyond frontal faces: Improving person recognition using multiple cues. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4804-4813, 2015. 6", + "[49] Chao Zhao, Wenlin Yao, Dian Yu, Kaiqiang Song, Dong Yu, and Jianshu Chen. Learning-by-narrating: Narrative pretraining for zero-shot dialogue comprehension. In Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers), pages 212-218, Dublin, Ireland, May 2022. Association for Computational Linguistics. 3", + "[50] Bolei Zhou, Agata Lapedriza, Aditya Khosla, Aude Oliva, and Antonio Torralba. Places: A 10 million image database for scene recognition. IEEE transactions on pattern analysis and machine intelligence, 40(6):1452-1464, 2017. 3, 6" + ], + "bbox": [ + 501, + 92, + 893, + 810 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "23340", + "bbox": [ + 478, + 945, + 519, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/014aa68e-4ee6-4ed7-996a-a0fac673a258_model.json b/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/014aa68e-4ee6-4ed7-996a-a0fac673a258_model.json new file mode 100644 index 0000000000000000000000000000000000000000..663a3085a478a1a3d807298942181a71cecb76ce --- /dev/null +++ b/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/014aa68e-4ee6-4ed7-996a-a0fac673a258_model.json @@ -0,0 +1,2189 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.18, + 0.131, + 0.79, + 0.175 + ], + "angle": 0, + "content": "MEGA: Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.19, + 0.203, + 0.777, + 0.256 + ], + "angle": 0, + "content": "Najmeh Sadoughi1, Xinyu Li1, Avijit Vajpayee1, David Fan1, Bing Shuai2, Hector Santos-Villalobos1, Vimal Bhat1, Rohith MV1 \n1Amazon Prime Video, 2AWS AI Labs" + }, + { + "type": "text", + "bbox": [ + 0.163, + 0.26, + 0.807, + 0.275 + ], + "angle": 0, + "content": "{nnnourab,xxnl,avivaj,fandavi,bshuai,hsantosv,vimalb,kurohith}@amazon.com" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.309, + 0.314, + 0.327 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.343, + 0.474, + 0.66 + ], + "angle": 0, + "content": "Previous research has studied the task of segmenting cinematic videos into scenes and into narrative acts. However, these studies have overlooked the essential task of multimodal alignment and fusion for effectively and efficiently processing long-form videos (\\(>60\\mathrm{min}\\)). In this paper, we introduce Multimodal alignmEnt aGgregation and distillAtion (MEGA) for cinematic long-video segmentation. MEGA tackles the challenge by leveraging multiple media modalities. The method coarsely aligns inputs of variable lengths and different modalities with alignment positional encoding. To maintain temporal synchronization while reducing computation, we further introduce an enhanced bottleneck fusion layer which uses temporal alignment. Additionally, MEGA employs a novel contrastive loss to synchronize and transfer labels across modalities, enabling act segmentation from labeled synopsis sentences on video shots. Our experimental results show that MEGA outperforms state-of-the-art methods on MovieNet dataset for scene segmentation (with an Average Precision improvement of \\(+1.19\\%\\)) and on TRI-POD dataset for act segmentation (with a Total Agreement improvement of \\(+5.51\\%\\))." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.693, + 0.208, + 0.709 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.471, + 0.901 + ], + "angle": 0, + "content": "In the world of video production, movies are composed of smaller units called shots, scenes, and acts. Shots are a continuous set of frames, a scene is a sequence of shots that tell a story, and an act is a thematic section of a narrative [14]. While computer vision has made significant strides in shot detection [39], scene and act segmentation remain a challenge, despite their potential for smart video navigation, advertisement insertion, and movie summarization. Cinematic content comprises of different data sources, including audio, visual, and text data, as well as derivative data sources from the narrative, including location, appearance, tone, or acoustic events. In this work, we will refer to all of these" + }, + { + "type": "image", + "bbox": [ + 0.52, + 0.311, + 0.882, + 0.503 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.515, + 0.895, + 0.577 + ], + "angle": 0, + "content": "Figure 1: MEGA works well on both scene segmentation and act segmentation tasks, outperforming previous work with significant margin. V,T*,T,A denotes video, screenplay, subtitle and audio respectively." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.594, + 0.895, + 0.64 + ], + "angle": 0, + "content": "input components as \"modalities\" of cinematic content. Previous work has not fully explored how to align and aggregate these modalities which have different granularities." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.644, + 0.897, + 0.903 + ], + "angle": 0, + "content": "We propose to address scene and act segmentation tasks with an unified multimodal Transformer. However, this approach presents two main challenges. Firstly, there is the issue of cross modality information synchronization and fusion at the shot level. Previous studies which use multimodal fusion for scene and act segmentation perform early [8, 32] or late fusion of features [35], and have not explored fusion strategies which utilize multimodal temporal alignment. Additionally, the fusion strategies that utilize temporal alignment such as merged attention or cross modality attention [9, 21] are computationally expensive and not generalizable to a large number of modalities. Secondly, due to the challenges associated with labeling a long video on act segmentation, the labels for act segmentation are provided on synopsis sentences [30] which do not provide timestamps. To avoid the more challenging task of cross-modal synchronization, previous studies on act segmentation [30, 32] rely" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "23331" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.471, + 0.152 + ], + "angle": 0, + "content": "on textual screenplay to transfer the labels from synopsis to movie, ignoring the rich multimodal information from the video, and introducing an additional dependency on screenplay data which is not always available." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.152, + 0.474, + 0.439 + ], + "angle": 0, + "content": "To address these challenges, we introduce Multimodal alignmEnt aGgregation and distillation (MEGA). MEGA includes a novel module called alignment positional encoding which aligns inputs of variable lengths and different modalities at a coarse temporal level. To fuse the aligned embeddings of different modalities in an efficient and effective manner, we adopt the bottleneck fusion tokens [28] and append a set of fusion tokens to each modality. These tokens share the same sequence length as the normalized positional encoding for different modalities, allowing us to inject them with the coarse temporal information, enabling information fusion in a better aligned embedding space. To address the issue of cross-domain knowledge transfer, we introduce a cross-modal synchronization approach. This method allows us to transfer the manually labeled act boundaries from synopsis level to movie level using rich multimodal information, enabling us to train MEGA directly on videos without relying on screenplay – which was a hard requirement for previous works [30, 32]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.44, + 0.471, + 0.56 + ], + "angle": 0, + "content": "We test our proposed alignment and aggregation modules on the Movienet-318 [18] and the TRIPOD datasets [30], and we test our cross modality synchronization module on TRIPOD alone, as the labels are provided on a different modality during training. Our proposed MEGA outperforms previous SoTA on scene segmentation on the Movienet-318 dataset (by \\(+1.19\\%\\) in AP) and on act segmentation on the TRIPOD dataset (by \\(+5.51\\%\\) in TA). Our contributions are:" + }, + { + "type": "text", + "bbox": [ + 0.09, + 0.567, + 0.468, + 0.611 + ], + "angle": 0, + "content": "1. Alignment positional encoding module and a fusion bottleneck layer that performs multimodal fusion with aligned multi-modality inputs." + }, + { + "type": "text", + "bbox": [ + 0.09, + 0.612, + 0.47, + 0.655 + ], + "angle": 0, + "content": "2. A cross-domain knowledge transfer module that synchronizes features across-domain, and enables knowledge distillation without requiring extra information." + }, + { + "type": "text", + "bbox": [ + 0.09, + 0.657, + 0.468, + 0.7 + ], + "angle": 0, + "content": "3. SoTA performance on scene and act segmentation tasks, with detailed ablations, which can be used as reference for future work." + }, + { + "type": "list", + "bbox": [ + 0.09, + 0.567, + 0.47, + 0.7 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.71, + 0.219, + 0.725 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.471, + 0.901 + ], + "angle": 0, + "content": "Scene Segmentation in Cinematic Content: Recent works on scene segmentation have explored self-supervised learning (SSL) [8,27,45]. Self-supervised pretext tasks have included maximizing the similarity between nearby shots compared to randomly selected ones [8], maximizing the similarity between pairs of images selected according to scene consistency [45], and maximizing the similarity between pairs of images selected according to pseudo scene boundaries [27]. While several previous works have used multimodal inputs for this task [8,35,45], they have either utilized late fusion of features with predefined weights for each" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.152 + ], + "angle": 0, + "content": "modality [35] or have utilized early integration of features derived via SSL [8, 45]. In this paper, we explore how to better align and integrate features from different modalities for scene segmentation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.154, + 0.895, + 0.44 + ], + "angle": 0, + "content": "Act Segmentation in Cinematic Content: Movie screenplays follow a general narrative structure on how a plot unfolds across the story. Several theories have been proposed in this domain dating as far back as Aristotle, who defined a 3 act structure with a beginning (protasis), middle (epitasis), and end (catastrophe) [33]. Modern screenplays are usually written with a 6 act structure [14], named as \"the setup\", \"the new situation\", \"progress\", \"complications and higher stakes\", \"the final push\", and \"the aftermath\", separated by five turning points (TPs). Prior approaches in narrative segmentation on movies have adopted the aforementioned 6 act structure and posed the problem as identifying the 5 TPs that separate these 6 acts. [32] is to our knowledge the only prior work that utilizes visual domain in act segmentation by using a pre-trained teacher model trained on textual input to train a student Graph Convolutional network with audio-visual-text representations as input. In contrast, our work uses a new multimodal fusion and distillation applied on the modalities which are available with the movie." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.444, + 0.895, + 0.655 + ], + "angle": 0, + "content": "Multimodal Aggregation: Previous SoTAs on multimodal fusion with transformers perform early fusion of the features as inputs to the transformer [19], merge attention between them requiring more memory [9,21], use cross attention between two modalities [9,44], or add cross-modal interactions more efficiently via bottleneck tokens or exchanging some of their latents [15, 28]. [28] provides information flow between modalities efficiently by utilizing bottleneck tokens to tame the quadratic complexity of pairwise attention. This global exchange between modalities may not be enough for long videos, which require an adaptive fusion in different temporal locations. Our model considers [28] as baseline and extends it to incorporate local information during information exchange between modalities." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.657, + 0.894, + 0.793 + ], + "angle": 0, + "content": "Positional Encoding: Previous studies on improving the positional encoding in long sequence modeling have mostly focused on adding relative distance positional encoding [24, 38, 40]. However, they do not offer solutions on better maintaining the relative position of latent tokens with respect to their starting point in time in long sequences with variable lengths, which is important for long movie narrative understanding [5, 14]. We propose Alignment Positional Encoding to bridge this gap." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Cross-Modality Synchronization & Distillation: To transfer the labels from synopsis to movie shots, we use cross-modality distillation. Previous cross-modality distillation studies for label transfer across modalities are focused on parallel data with the same granularity [2,3,12], or where the alignment is known [31]. Alignment of features at different granularities in the same modality, such as screenplay" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.957 + ], + "angle": 0, + "content": "23332" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.226 + ], + "angle": 0, + "content": "scenes to synopsis sentences [26, 49] and across modalities such as aligning synopsis sentences to visual shots [42, 47], book chapters to visual scenes [43] have been previously explored. While majority of these works rely on unsupervised optimization techniques [26, 42, 43, 49], there are studies that use supervised labels to improve the representations used for optimization [47]. We present an alignment approach with self-supervised loss for synchronizing data in different modalities of cinematic content to enable distillation." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.242, + 0.212, + 0.259 + ], + "angle": 0, + "content": "3. Methodology" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.268, + 0.473, + 0.584 + ], + "angle": 0, + "content": "MEGA processes long videos and performs video segmentation in three major steps (Fig. 2). First, a video \\( V \\) is chunked into shots, and multiple features such as scene related features and sound event features are extracted at the shot-level (Sec. 3.1). The system is built on shot-level representation for two reasons: (1) scene and act boundaries always align with shot boundaries, and (2) the content within a shot remains similar, which allows efficient yet meaningful sampling without losing important information. Second, the embeddings from different input samples and each modality are coarsely aligned with a proposed alignment embedding (Sec. 3.2), and the alignment positional tokens are used to refine the commonly used bottleneck fusion tokens for cross-modal feature fusion (Sec. 3.2). Third, a linear layer is applied on top of the fused representations to generate scene and act boundaries (Sec. 3.3). Finally, to address the challenge of cross-domain knowledge transfer where labels from one domain may not directly align with another domain (e.g. act labels on synopsis sentences do not have movie-level timing information), we propose a cross-modal synchronization module that is simple yet effective (Sec. 3.4)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.595, + 0.222, + 0.611 + ], + "angle": 0, + "content": "3.1. Preprocessing" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.618, + 0.472, + 0.856 + ], + "angle": 0, + "content": "We chose to utilize Transnet-v2 [39] for shot segmentation due to its superior performance and efficiency. We list our selection of pre-trained models and associated parameters in Tab. 1. As each pretrained feature extraction model has different requirements for input resolution and sampling rate, we first sample the input at various sample rates (as shown in Table 1). It is worth noting that the \\(\\mathrm{CLIP}_{\\mathrm{movie}}\\) model is the CLIP [34] model with ViT-B/32 backbone fine-tuned on paired IMDB-image/text dataset. IMDB-image dataset comprises 1.6M images from 31.3K unique movies/TV series with 761 unique textual labels. The features attributed to each shot are the ones with overlap with the shot time stamp (More details are in Appendix). After feature extraction, we aggregate the features for each shot and normalize the feature dimension with linear projection as:" + }, + { + "type": "equation", + "bbox": [ + 0.18, + 0.857, + 0.47, + 0.905 + ], + "angle": 0, + "content": "\\[\nE _ {i} ^ {m} = g ^ {m} \\left(\\frac {1}{T _ {i} ^ {m}} \\sum_ {j = 1} ^ {T _ {i} ^ {m}} S _ {i j} ^ {m}\\right) \\tag {1}\n\\]" + }, + { + "type": "table", + "bbox": [ + 0.507, + 0.089, + 0.888, + 0.217 + ], + "angle": 0, + "content": "
Feature extractorInput Freq.Input Res.Feature dim.
Visual input
BASSL [27] (bassi)Varying22422048
ResNetPlace [50] (place)1Hz22422048
ResNeXt101 [46] (appr)1Hz22422048
I3D [6] (action)16Hz16 × 22422048
CLIPmovie (clip)1Hz2242768
Acoustic input
PANNs [23] (audio)1Hz10 × 32K2048
Linguistic input
all-MiniLM-L6-v2 [1] (text)Varying-384
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.228, + 0.892, + 0.258 + ], + "angle": 0, + "content": "Table 1: Sampling strategy and feature extraction backbones used for different modalities." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.268, + 0.894, + 0.343 + ], + "angle": 0, + "content": "where \\( E_{i}^{m}\\in \\mathbb{R}^{C} \\) denotes the embedding from the \\( i \\)-th shot of \\( m \\)-th modality, \\( S_{ij}^{m}\\in \\mathbb{R}^{D^{m}} \\) is the \\( j \\)-th sampled feature of \\( m \\)-th modality from \\( i \\)-th shot, and \\( g^{m} \\) is a linear projection layer that projects feature dimension for \\( m \\)-th modality to a common dimension \\( C \\) across all modalities." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.344, + 0.895, + 0.419 + ], + "angle": 0, + "content": "While it is possible to create an end-to-end system starting from raw shot inputs and training the model from scratch, pre-extracting the features from pretrained models is generally more scalable and efficient in actual industrial scenarios, hence we rely on the latter." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.43, + 0.829, + 0.446 + ], + "angle": 0, + "content": "3.2. Cross-modality Alignment and Fusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.454, + 0.895, + 0.665 + ], + "angle": 0, + "content": "For long video segmentation into scenes and acts it is important to model short and long term context and perform effective multimodal fusion. However, the commonly used learnable positional embedding only provides fine-grained granularity and is not suitable for high-level semantic alignment across modalities. Furthermore, for tasks such as act segmentation we expect consistent patterns at normalized position of temporal inputs as the theory suggests approximate locations for each turning point (i.e., \\(10\\%\\), \\(25\\%\\), \\(50\\%\\), \\(75\\%\\), \\(95\\%\\) [5, 14, 30]). Hence, in addition to using the traditional positional encoding, we introduce Alignment Positional Encoding layer \\(\\in \\mathbb{R}^{L_n\\times C}\\), which is a learnable embedding layer, for which the index at \\(i\\)-th temporal unit (e.g., shot) is derived by:" + }, + { + "type": "equation", + "bbox": [ + 0.619, + 0.665, + 0.892, + 0.699 + ], + "angle": 0, + "content": "\\[\ni _ {\\text {a l i g n}} = \\operatorname {f l o o r} \\left(\\frac {L _ {n}}{L} i\\right) \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.894, + 0.854 + ], + "angle": 0, + "content": "where \\( L \\) is the temporal dimension (e.g., number of shots) and \\( L_{n} \\) is the length of alignment positional encoding which is a hyper-parameter \\( (L_{n} < L) \\). We add the alignment positional encoding to the features in conjunction with the conventional positional encoding (see Fig 2). This module is shared across different modalities. This module provides extra information to the network that can be helpful in learning from long training samples with varying lengths, and in coarsely aligning inputs from different modalities before information fusion." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Inspired by previous works [9, 28, 44], we choose cross-modal feature fusion, which has been shown to be more effective than early or late fusion. To make our approach scale to" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "23333" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.11, + 0.089, + 0.852, + 0.266 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.271, + 0.895, + 0.335 + ], + "angle": 0, + "content": "Figure 2: The pipeline of the proposed method includes 1) Preprocessing: splitting the video into shots, extraction of features from each shot, pooling and normalization 2) Cross modality fusion and alignment: with the help of alignment positional encoding and bottleneck fusion tokens, 3) Scene/Act Segmentation comprising the segmentation heads. For Scene Segmentation, CE loss is used and for Act Segmentation knowledge transfer loss is used (refer to Sec. 3.4 for details)" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.369, + 0.473, + 0.52 + ], + "angle": 0, + "content": "multiple modalities, we propose an efficient temporal bottleneck fusion based on [28], and follow their mid-fusion strategy, which comprises of an unimodal transformer encoder followed by a multimodal transformer encoder (See Fig. 2). While [28] proposes to use bottleneck tokens for fusing information across different modalities, these tokens learn to integrate the information across modalities in a global manner. We propose to use \\( L_{n} \\) fusion tokens, and then integrate them with the same Normalized Positional Encoding to align them with features on the coarse temporal scale (Fig. 3)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.521, + 0.474, + 0.643 + ], + "angle": 0, + "content": "The transformer layer per modality then takes in an extra set of aligned fusion tokens concatenated with its input (Fig 2), making it much more efficient compared to other methods such as merged attention or pairwise cross-attention with respect to the number of modalities [9, 21]. Finally, the latent tokens per modality from the last fusion layer (i.e., \\( Z^{m} \\) for m-th modality) are concatenated as the fused representation:" + }, + { + "type": "equation", + "bbox": [ + 0.102, + 0.654, + 0.471, + 0.675 + ], + "angle": 0, + "content": "\\[\nZ ^ {\\text {f u s e d}} = \\operatorname {c o n c a t} _ {C} (Z) = \\operatorname {c o n c a t} _ {C} \\left(\\left[ Z ^ {1}, \\dots , Z ^ {M} \\right]\\right) \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.685, + 0.47, + 0.716 + ], + "angle": 0, + "content": "where \\(\\mathrm{concat}_C(*)\\) stands for channel-wise concatenation and \\(M\\) is the number of modalities." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.728, + 0.3, + 0.745 + ], + "angle": 0, + "content": "3.3. Scene/Act Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.752, + 0.471, + 0.813 + ], + "angle": 0, + "content": "MEGA adopts a similar approach to previous works [8, 27, 45], where scene segmentation is framed as a binary classification task using a key-shot representation from a window of \\(2 \\times k + 1\\) shots (\\(k\\)-shots before and after):" + }, + { + "type": "equation", + "bbox": [ + 0.208, + 0.825, + 0.47, + 0.844 + ], + "angle": 0, + "content": "\\[\ny _ {i} = \\varphi \\left(Z _ {i} ^ {\\text {f u s e d}}; \\theta_ {s}\\right) \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.471, + 0.903 + ], + "angle": 0, + "content": "where \\( y_{i} \\) is the logit prediction for the \\( i \\)-th key-shot. \\( \\varphi \\) denotes the linear layer with learnable parameters \\( \\theta_{s} \\) and a cross entropy loss is utilized [8, 27, 45]." + }, + { + "type": "image", + "bbox": [ + 0.529, + 0.366, + 0.871, + 0.525 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.538, + 0.895, + 0.676 + ], + "angle": 0, + "content": "Figure 3: Illustration of Normalized Positional Encoding integration to the temporal tokens in one modality. This figure shows the integration of normalized Positional Encoding with 1) temporal shots for one modality and 2) bottleneck fusion tokens, where \\( L = 15 \\) and \\( L_{n} = 3 \\). For (1) \\( i_{\\text{align}} \\) is obtained per shot index, \\( i \\), and then each shot is integrated with normalized PE. For (2) each randomly initialized bottleneck token is integrated with normalized PE for its corresponding index." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.711, + 0.895, + 0.817 + ], + "angle": 0, + "content": "The act segmentation task is formulated as \\( N_{tp} \\) linear prediction heads (\\( N_{tp} \\) is the number of turning points, and \\( \\theta_{a_n} \\) denotes the head parameters for \\( n \\)-th turning point [32]), for each individual shot from a temporal model that takes all the shots of the movie as input. To make a prediction at the \\( i \\)-th shot for the \\( n \\)-th act boundary (\\( n \\in \\{1, \\dots, N_{tp}\\} \\)), we use:" + }, + { + "type": "equation", + "bbox": [ + 0.623, + 0.831, + 0.893, + 0.851 + ], + "angle": 0, + "content": "\\[\ny _ {i n} = \\varphi \\left(Z _ {i} ^ {\\text {f u s e d}}; \\theta_ {a _ {n}}\\right) \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.871, + 0.893, + 0.903 + ], + "angle": 0, + "content": "where \\( y_{in} \\) is the logit prediction for \\( i \\)-th shot and \\( n \\)-th turning point." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "23334" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.091, + 0.383, + 0.108 + ], + "angle": 0, + "content": "3.4. Cross-domain Knowledge Transfer" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.114, + 0.471, + 0.25 + ], + "angle": 0, + "content": "It is quite common during machine learning that certain modalities may lack annotations that are directly available in other modalities with different information granularity. To address this, we propose a cross-modality synchronization scheme that enables cross-modal distillation. We utilize this module for act segmentation where we aim to transfer act labels from synopsis sentences to movie-level timestamps. Importantly, our approach does not require additional information, such as screenplay [32], to bridge the gap." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.251, + 0.474, + 0.508 + ], + "angle": 0, + "content": "Our knowledge distillation utilizes (1) an individual network to learn the synopsis-based act segmentation in a supervised manner with cross-entropy loss similar to [31]; and (2) a novel synchronization approach between synopsis and movie. For (1) we use the same architecture mentioned in Secs. 3.1, 3.2, setting \\( C_{\\mathrm{fused}} \\) equal to the multimodal shot model setting. Additionally, similar to shot level linear prediction head (See Eq. 5), we use a sentence level linear prediction head, resulting in \\( q_{in} \\) logits for the \\( i \\)-th sentence of \\( n \\)-th TP. A supervised Cross Entropy loss is used to learn the synopsis labels from predictions for each turning point \\( (\\mathcal{L}_{ce}) \\). For (2) we seek a synchronization matrix \\( W \\in \\mathbb{R}^{L_{sh} \\times L_{syn}} \\) between \\( L_{sh} \\) shots and \\( L_{syn} \\) synopsis sentences for a sample, where \\( w_{ij} = 1 \\) if the \\( i \\)-th shot matches with the \\( j \\)-th synopsis sentence and \\( w_{ij} = 0 \\), otherwise. Assuming \\( F(:, \\theta) \\) represents a parametric reward function (with parameters \\( \\theta \\)), to find \\( W \\), we define an objective as:" + }, + { + "type": "equation", + "bbox": [ + 0.16, + 0.519, + 0.47, + 0.553 + ], + "angle": 0, + "content": "\\[\n\\max _ {W, \\theta} \\sum_ {i, j} w _ {i j} F (.; \\theta) - \\lambda \\sum_ {i, j} | w _ {i, j} | \\tag {6}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.218, + 0.556, + 0.332, + 0.572 + ], + "angle": 0, + "content": "\\[\ns. t. 0 \\leq w _ {i j} \\leq 1\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.584, + 0.47, + 0.644 + ], + "angle": 0, + "content": "Expectation-Maximization algorithm is used to solve the objective in Eq. 6. We estimate the target variable \\( W \\) via fixed parameters (i.e., \\( \\theta \\)) in the E-step, and update the parameters while the target variable is known in the M-step." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.644, + 0.47, + 0.749 + ], + "angle": 0, + "content": "E-step: Assuming \\( F(:,\\theta) \\) returns the similarity of input shot and synopsis sentence pair, the E-step has a closed form solution. In the E-step, following [26], we reduce the search space during optimization to only the pairs which are inside a diagonal boundary (see the proof for E-step and visualization of expected synchronization matrix for different examples in Appendix)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.471, + 0.901 + ], + "angle": 0, + "content": "M-step: Using all samples in a batch with \\( L_{\\mathrm{SH}} \\), \\( L_{\\mathrm{SYN}} \\) total number of shots and synopsis sentences, we form their cosine similarity matrix of dimension \\( L_{\\mathrm{SH}} \\times L_{\\mathrm{SYN}} \\). For each query (synopsis sentence/movie shot, respectively), the positive keys (movie shot/synopsis sentence, respectively) are derived from the expectation step. Negative keys are the keys lying outside the diagonal boundary of the similarity matrix of shot-synopsis pairs for one movie [26], and all the keys from other movies within the batch. Here each query (synopsis sentence/movie shot, respectively) can have more than one" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.893, + 0.152 + ], + "angle": 0, + "content": "positive key (movie shot/synopsis sentence, respectively) attached to it. Following [20], we adopt a modified version of the InfoNCE loss and combine it with the symmetric contrastive loss [34] as:" + }, + { + "type": "equation", + "bbox": [ + 0.516, + 0.162, + 0.893, + 0.25 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {L} _ {c} = - \\sum_ {i = 1} ^ {L _ {\\mathrm {S Y N}}} \\frac {1}{| \\hat {y} _ {i} |} \\sum_ {k = 1} ^ {L _ {\\mathrm {S H}}} \\hat {y} _ {i k} \\log \\frac {\\exp \\left(v _ {i} u _ {k} / \\tau\\right)}{\\sum_ {j = 1} ^ {L _ {\\mathrm {S H}}} \\exp \\left(v _ {i} u _ {j} / \\tau\\right)} - \\tag {7} \\\\ \\sum_ {i = 1} ^ {L _ {\\mathrm {S H}}} \\frac {1}{| \\hat {y} _ {i} ^ {T} |} \\sum_ {k = 1} ^ {L _ {\\mathrm {S Y N}}} \\hat {y} _ {i k} ^ {T} \\log \\frac {e x p (u _ {i} v _ {k} / \\tau)}{\\sum_ {j = 1} ^ {L _ {\\mathrm {S Y N}}} e x p (u _ {i} v _ {j} / \\tau)} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.258, + 0.893, + 0.318 + ], + "angle": 0, + "content": "where \\(\\tau\\) is a learnable temperature parameter, and \\(\\hat{y}_{ij}\\) is a binary indicator of positive vs. negative pairs, \\(u_{i}\\) is the normalized feature for the \\(i\\)-th shot and \\(v_{i}\\) is the normalized feature for the \\(i\\)-th synopsis sentence." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.318, + 0.895, + 0.529 + ], + "angle": 0, + "content": "Knowledge distillation: Knowledge distillation is used to transfer the knowledge available for the training samples on synopsis. The predictions from the synopsis model are mapped to shots using a matrix of their similarities as calculated in the maximization step, for each sample. The similarity scores for each shot are normalized along the synopsis sentences with softmax. The logit predictions from synopsis model are transferred to shots by multiplication with the normalized similarity matrix. A softmax along the shots is applied to the transferred logits to derive the probability scores for each shot. Following [31], we use a Kullback-Leibler divergence loss between predicted outputs for each shot and the transferred probabilities \\((\\mathcal{L}_{kd})\\) (More details are provided in Appendix.)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.53, + 0.893, + 0.56 + ], + "angle": 0, + "content": "The cross-domain knowledge transfer module can be trained by simply adding the losses together as:" + }, + { + "type": "equation", + "bbox": [ + 0.583, + 0.571, + 0.892, + 0.587 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} = \\alpha_ {c} \\mathcal {L} _ {c} + \\alpha_ {c e} \\mathcal {L} _ {c e} + \\alpha_ {k d} \\mathcal {L} _ {k d} \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.599, + 0.892, + 0.629 + ], + "angle": 0, + "content": "where \\(\\alpha_{c},\\alpha_{ce}\\) , and \\(\\alpha_{kd}\\) are hyperparameters that control the weights of the three losses." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.642, + 0.634, + 0.659 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.667, + 0.596, + 0.681 + ], + "angle": 0, + "content": "4.1. Dataset" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.69, + 0.894, + 0.795 + ], + "angle": 0, + "content": "We test our model on two commonly used dataset: Movienet-318 [18]: consists of 1100 movies, out of which 318 movies are annotated for the task of scene segmentation. The annotated dataset is split into 190, 64, and 64 movies for train, validation and test splits, respectively. We report the Average Precision (AP) and F1-score (F1) on the test split following previous work [35, 45]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.894, + 0.9 + ], + "angle": 0, + "content": "TRIPOD [32] includes 122 movies, split into 84, and 38 movies for train and test, respectively. This dataset includes the annotations of 6 act boundaries (\"the setup\", \"the new situation\", \"progress\", \"complications and higher stakes\", \"the final push\", \"the aftermath\") on the movie synopsis sentences for the training set, and on the movie screenplay scenes for the test set. The authors also have released soft" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "23335" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.198 + ], + "angle": 0, + "content": "probability scores (silver annotations) for the training set, using \\([30]^1\\). To find the timestamps for the screenplay scenes in the movie, following [32] we used Dynamic Time Warping (DTW) to align the timed subtitles from the movie to the monologue lines in the screenplay. Following [32], we use total agreement (TA), partial agreement (PA) and distance (D) as evaluation metrics." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.206, + 0.295, + 0.222 + ], + "angle": 0, + "content": "4.2. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.228, + 0.471, + 0.349 + ], + "angle": 0, + "content": "For scene segmentation: We train our model with 8 V100 GPUs with total batch size of 1024. The Adam [22] optimizer is used with learning rate of 1e-4. We train the model for 20 epochs. GeLU [16] is used as activation function by default, we use weighted cross entropy to balance the positive and negative samples at batch level. We choose shot sequence length of \\(17(k = 8)\\) following [27]. We set \\(L_{n} = 2\\) for this model." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.35, + 0.473, + 0.516 + ], + "angle": 0, + "content": "For act segmentation: We train our model with 4 V100 GPUs with total batch size of 4. The SGD optimizer is used with learning rate of 1e-3. We train the model for 10 epochs. \\(\\lambda\\) in Eq. 6 is empirically set differently for each synopsis sentence of each sample, by finding \\(99\\%\\) percentile of the similarity scores between the synopsis sentence and all the shots corresponding to that sample. \\(\\alpha_{c}, \\alpha_{ce}, \\alpha_{kd}\\) are set to 1, 1, and 10. We set \\(L_{n} = 100\\) for this the shot model and \\(L_{n} = 20\\) for the synopsis model. We use max pooling to aggregate the shot-level predictions to scene level. We use all shots from a video for act segmentation." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.524, + 0.218, + 0.539 + ], + "angle": 0, + "content": "4.3. Main Results" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.547, + 0.473, + 0.773 + ], + "angle": 0, + "content": "SoTA on Scene Segmentation. We first show MEGA outperforms previous SoTA on MovieNet318 [27] for scene segmentation \\((+1.19\\%)\\) on AP and \\(+8.28\\%\\) on F1). With the same input visual features, MEGA outperforms previous SoTA [27] (Tab. \\(2 + 0.52\\%\\) on AP and \\(+3.69\\%\\) on F1), which indicates that the proposed approach is effective. Thanks to the proposed cross-modality fusion module, the MEGA generalizes and benefits from additional information extracted from visual signals. MEGA with 3 visual modalities (clip, place, and bassl) outperforms single modality model by \\(+0.67\\%\\) on AP and \\(+4.59\\%\\) on F1, which shows the proposed fusion works as expected. It is worth mentioning that the proposed method is scalable and generalizes to various number of modalities at different scales, which makes it flexible for real-world applications." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.774, + 0.472, + 0.88 + ], + "angle": 0, + "content": "SoTA on Act Segmentation. We then show that MEGA establishes the new SoTA performance on act segmentation on TRIPOD dataset (Tab. 3). We first show that MEGA outperforms previous SoTA on TRIPOD [32] dataset With only visual signals as input. Comparing to other works that take textural inputs [29, 32], MEGA is able to achieve better performance. Furthermore, in real-world applications, the" + }, + { + "type": "table", + "bbox": [ + 0.518, + 0.089, + 0.877, + 0.303 + ], + "angle": 0, + "content": "
ApproachModalityPretrained onAP↑ [%]FI↑ [%]
Random [35]--8.2-
Visual only input
GraphCut [36]VPlaces [50]14.1-
SCSA [7]VPlaces [50]14.7-
DP [13]VPlaces [50]15.5-
Grouping [37]VPlaces [50]17.6-
StoryGraph [41]VPlaces [50]25.1-
Siamese [4]VPlaces [50]28.1-
LGSS [35]VPlaces [35]39.0-
LGSS [35]VCast [17,48]15.9-
LGSS [35]VAction [11]32.1-
ShotCoL [8]†VMovienet [18]52.8949.17
SCRL [45]VMovienet [18]54.8251.43
BaSSL [27]VMovienet [18]57.447.02
MEGAVMovienet [18]57.9250.71
MEGAVM+P+I58.5955.30
" + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.309, + 0.895, + 0.356 + ], + "angle": 0, + "content": "Table 2: Scene boundary detection: comparison with SoTA. \\(\\dagger\\)means the numbers are copied from [45]. M+P+I denotes pre-trained on Movienet [18], Places [50] and IMDB." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.368, + 0.895, + 0.548 + ], + "angle": 0, + "content": "visual input (the video) is often easier to obtain than textual inputs such as screenplay [32]. We further show that MEGA* (Tab. 3), which swaps our synchronization module to use similar synchronization as SoTA [32], outperforms GRAPHTP, which demonstrates the effectiveness of proposed approach including the alignment and fusion modules. It is worth mentioning that, with multiple features extracted from visual media modality alone, MEGA outperforms previous SOTA which makes the proposed model applicable for real-world scenarios, as it is usually harder to get additional media modalities (e.g., screenplay) which are used in other works." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.55, + 0.897, + 0.716 + ], + "angle": 0, + "content": "By further aggregating the results from text input, MEGA establishes the new state-of-the-art on TRIPOD dataset (Tab. 3). MEGA almost doubles the performance of previous work [29, 32] with \\(+5.51\\%\\) TA, \\(+9.15\\%\\) PA, \\(-\\%0.81\\) D. This shows the proposed multimodal fusion scales and generalizes well to multiple modalities. The cross-modality distillation also works robustly for various settings. We noticed that adding the acoustic features is not always helpful to the performance (Tab. 3), probably because acoustic information provides redundant or not useful information for the task of act boundary segmentation." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.726, + 0.612, + 0.74 + ], + "angle": 0, + "content": "4.4. Ablations" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.895, + 0.901 + ], + "angle": 0, + "content": "We perform ablations to examine the effectiveness of major building blocks of MEGA. We use features extracted from visual media modality (for scene segmentation: clip, place, Bassl and for act segmentation: clip, appr, action, place), with the proposed normalized positional encoding, multi-modality bottleneck fusion, and cross-modality synchronization by default unless specified. The training and evaluation follows same protocols as mentioned in Sec. 4.3. Alignment Positional Encoding. We report the ablations on Alignment PE in Tab. 4a. We notice that the proposed" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.411, + 0.901 + ], + "angle": 0, + "content": "1https://github.com/ppapalampidi/GraphTP" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.946, + 0.521, + 0.957 + ], + "angle": 0, + "content": "23336" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.088, + 0.482, + 0.326 + ], + "angle": 0, + "content": "
ApproachModalityModality for synch.TA↑ [%]PA↑ [%]D↓ [%]
Random (Evenly dist.) [32]-T*4.826.9512.35
Theory [14, 30]-T*4.416.3211.03
Distribution position [32]-T*5.597.3710.74
Single modality input
TEXTRANK [25]T*T*6.1810.0017.77
SCENESUM [10]T*T*4.417.8916.86
TAM [29]T*T*7.949.479.42
GRAPHTP [32]T*T*6.7610.009.62
MEGA*VT*10.5114.548.98
MEGAVV13.9320.729.19
Multi-modality input
TEXTRANK [25]T*+A+VT*6.1810.0018.90
SCENESUM [10]T*+A+VT*6.7611.0518.93
TAM [29]T*+A+VT*7.3610.0010.01
GRAPHTP [32]T*+A+VT*9.1212.639.77
MEGA*T+VT*11.1415.208.96
MEGAT+VT+V14.6321.788.96
MEGA*T+A+VT*10.0014.088.96
MEGAT+A+VT+A+V14.1922.109.68
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.336, + 0.473, + 0.398 + ], + "angle": 0, + "content": "Table 3: TP identification: comparison with SoTA. MEGA* denotes the MEGA using the same synchronization as [30] for fair comparison. T*,V,T,A denote Textual-screenplay, Visual, Textual-subtitle and Acoustic features, respectively." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.411, + 0.47, + 0.622 + ], + "angle": 0, + "content": "alignment PE consistently improves the performance on both scene and act segmentation tasks, while act segmentation benefits more significantly from it. This is because of two reasons: 1) inputs to the act segmentation model have variable lengths (all the shots from a video) as opposed to scene segmentation which has fixed length inputs, hence the alignment PE adds more information to the act segmentation model; and 2) Alignment PE is shared across all modalities and fusion layer and its absence causes more harm to sequences with longer lengths, as act segmentation takes longer shot sequences (entire video) compared to scene segmentation (17 shots). Overall, the drop in performance indicates that the proposed Alignment P.E. is an essential component for video segmentation tasks." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.624, + 0.47, + 0.746 + ], + "angle": 0, + "content": "We further remove the proposed Alignment PE from bottleneck fusion tokens and show results in Tab. 4b. We observe a performance drop when removing the Alignment PE. It is worth mentioning that the performance drop is more noticeable when multiple modalities are involved, (e.g. V + T model), which suggests that the information from subtitles requires precise temporal alignment in order to be effective during multimodal fusion." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.748, + 0.471, + 0.839 + ], + "angle": 0, + "content": "Multimodal Fusion Strategies. Tab. 4c compares our proposed fusion tokens with the commonly used late fusion strategy. The results show that the temporal bottleneck fusion clearly outperforms late fusion, demonstrating the effectiveness of aligned bottleneck tokens in improving the performance across both tasks." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.473, + 0.902 + ], + "angle": 0, + "content": "Different Input Modalities. We study the impact of different modalities by removing them from the input and present results on scene segmentation and act segmentation. In scene segmentation (Tab. 4d), we find that the Bassl feature fol" + }, + { + "type": "table", + "bbox": [ + 0.513, + 0.089, + 0.882, + 0.159 + ], + "angle": 0, + "content": "
caseScene Seg.Act Segmentation
AP↑TA↑PA↑D↓
w/o align. PE57.775.297.3731.04
w. align. PE58.5913.9320.729.19
" + }, + { + "type": "table_caption", + "bbox": [ + 0.558, + 0.162, + 0.835, + 0.176 + ], + "angle": 0, + "content": "(a) Effectiveness of Alignment Positional Encoding." + }, + { + "type": "table", + "bbox": [ + 0.512, + 0.187, + 0.882, + 0.282 + ], + "angle": 0, + "content": "
casemodalityScene Seg.Act Segmentation
AP↑TA↑PA↑D↓
w/o align.PEV58.3113.6020.539.47
w. align.PEV58.5913.9320.729.19
w/o align.PEV + T-13.0120.139.56
w. align.PEV + T-14.6321.788.96
" + }, + { + "type": "table_caption", + "bbox": [ + 0.506, + 0.285, + 0.886, + 0.298 + ], + "angle": 0, + "content": "(b) Effectiveness of Normalized Positional Encoding in bottleneck tokens." + }, + { + "type": "table", + "bbox": [ + 0.516, + 0.31, + 0.879, + 0.38 + ], + "angle": 0, + "content": "
MM. integ. typeScene Seg.Act Segmentation
AP↑TA↑PA↑D↓
LateFusion58.2412.5719.2110.00
Bottleneck58.5913.9320.729.19
" + }, + { + "type": "table_caption", + "bbox": [ + 0.607, + 0.384, + 0.786, + 0.397 + ], + "angle": 0, + "content": "(c) Multi-modal fusion strategies." + }, + { + "type": "table", + "bbox": [ + 0.508, + 0.409, + 0.63, + 0.499 + ], + "angle": 0, + "content": "
changeAP↑
-clip58.09
-place57.51
-bassl51.88
-clip-place57.92
-58.59
" + }, + { + "type": "table_caption", + "bbox": [ + 0.501, + 0.502, + 0.634, + 0.527 + ], + "angle": 0, + "content": "(d) Impact from input modalities on scene seg." + }, + { + "type": "table", + "bbox": [ + 0.69, + 0.409, + 0.887, + 0.499 + ], + "angle": 0, + "content": "
changeTA↑PA↑D↓
-clip6.0910.6621.81
-place13.5719.879.22
-action13.3120.2010.38
-appr13.4220.598.85
-13.9320.729.19
+subtitle14.6321.788.96
" + }, + { + "type": "table_caption", + "bbox": [ + 0.686, + 0.503, + 0.892, + 0.527 + ], + "angle": 0, + "content": "(e) Impact from input modalities on act segmentation." + }, + { + "type": "table", + "bbox": [ + 0.52, + 0.539, + 0.875, + 0.604 + ], + "angle": 0, + "content": "
synopsis synch. byM for synch.TA↑PA↑D↓
[30]T*10.5114.548.98
MEGAV13.9320.729.19
MEGAV + T14.6321.788.96
" + }, + { + "type": "table_caption", + "bbox": [ + 0.512, + 0.606, + 0.88, + 0.632 + ], + "angle": 0, + "content": "(f) Impact of Synchronization with multimodal video features on act segmentation." + }, + { + "type": "table", + "bbox": [ + 0.508, + 0.644, + 0.892, + 0.702 + ], + "angle": 0, + "content": "
ApproachFeature Set Pretrained onAP↑Params↓SPS↑
BaSSL [27]Movienet57.415.77M6244.99
LGSS [35]M+P+I52.9366.16M206.36
MEGAM+P+I58.5967.57M1736.13
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.705, + 0.897, + 0.731 + ], + "angle": 0, + "content": "(g) Impact from feature set and model size on scene seg. SPS denotes # of samples per second." + }, + { + "type": "table", + "bbox": [ + 0.507, + 0.742, + 0.897, + 0.799 + ], + "angle": 0, + "content": "
ApproachFeature SetTA↑PA↑D↓Params↓SPS↑
GRAPHTP [32]Set1 [32]9.1212.639.770.745M25.40
GRAPHTP [32]Set24.727.379.696.78M14.36
MEGASet214.1922.109.686.78M18.24
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.804, + 0.897, + 0.841 + ], + "angle": 0, + "content": "(h) Impact from feature set and model size on act seg. Set1 includes Visual (appr), Audio (YAMNet), Textual (script-USE). Set2 has Visual (appr,clip,action.place), Audio (audio), Textual (text from subtitle)." + }, + { + "type": "table_caption", + "bbox": [ + 0.531, + 0.843, + 0.859, + 0.858 + ], + "angle": 0, + "content": "Table 4: Ablation studies on MEGA components." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.895, + 0.901 + ], + "angle": 0, + "content": "lowed by place are the most important. This is because the BaSSL [27] model is pretrained for scene segmenta-" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "23337" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.272 + ], + "angle": 0, + "content": "tion and place consistency is critical for scene segmentation. In act segmentation (Tab. 4e), we find that the CLIP feature pre-trained on IMDB, followed by subtitle are the most important features. This is because the clip model is pre-trained on abstract concepts (e.g. genre, micro genre, character type and coarse key places), thus the CLIP feature contains richer semantics, and subtitle provides complementary rich semantic information. These high level semantics are considered useful for act segmentation. Overall, when all the features are included, the model is able to leverage the unique information provided by each feature and yields the best performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.274, + 0.473, + 0.516 + ], + "angle": 0, + "content": "Cross-modality Synchronization. Tab. 4f studies the effectiveness of the proposed cross modality synchronization on act segmentation. To establish a baseline, we use the probability scores provided by [32] and derived by aligning synopsis sentences to scenes using screenplay [30] (T* in Tab. 4f denotes screenplay). For a fair comparison, we repeat the scores provided for each scene on all of its shots and then re-normalize2. MEGA with visual only input outperforms [30] across two metrics (PA and TA) and when we add the subtitle features (T in Tab. 4f denotes subtitle), MEGA outperforms [30] across all the metrics. The results demonstrate that the proposed cross-domain synchronization works effectively and generalize well to various modalities. It is worth mentioning that the proposed method generates act segmentation without requiring the screenplay, which makes it practical for various industrial applications." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.516, + 0.473, + 0.637 + ], + "angle": 0, + "content": "Impact of Feature Set. In Tab. 4g, we examine whether feature set plays an outsized role in MEGA's improved performance over other methods. On the same feature set of \\(\\mathrm{M} + \\mathrm{P} + \\mathrm{I}\\), we outperform LGSS [35] while only introducing a small number of additional parameters. BaSSL [27] achieves slightly lower performance using only Movienet features, indicating that the use of additional features is not the primary reason for our improved performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.638, + 0.473, + 0.744 + ], + "angle": 0, + "content": "Impact of Model Size. We finally look into the impact of model size on the performance. To establish the fair comparison, we first expand GRAPHTP [32] which shares the same input as MEGA to roughly the same number of parameters as MEGA. Our results on act segmentation (Tab. 4h) show that MEGA outperforms the previous SoTA, GRAPHTP [32], which indicates the MEGA has efficient and effective design." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.754, + 0.33, + 0.77 + ], + "angle": 0, + "content": "4.5. Fusion with Audio Modality" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.778, + 0.472, + 0.84 + ], + "angle": 0, + "content": "We also experimented with the effect of adding audio. Movienet [18] has released Short Time Fourier Transform (STFT) features extracted from audio files. We use the same audio backbone as [35]. However, by adding audio features" + }, + { + "type": "table", + "bbox": [ + 0.55, + 0.088, + 0.875, + 0.23 + ], + "angle": 0, + "content": "
ApproachModalityAP↑ [%]
LGSS [35]V(place)39.00
ShotCoL [8];V46.77
SCRL [45]V54.55
MEGAV(place,clip,bassl)58.59
LGSS [35]V(place)+A43.4
ShotCoL [8];V+A44.32
SCRL [45]V+A50.80
MEGAV(place,clip,bassl)+A55.36
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.24, + 0.892, + 0.256 + ], + "angle": 0, + "content": "Table 5: Scene Seg. with audio. \\(\\ddagger\\)denotes copying from [45]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.265, + 0.895, + 0.493 + ], + "angle": 0, + "content": "in MEGA, we see a drop in the performance (see Tab. 5). Although [8, 35] have shown improvements across multiple models by adding the audio modality across Movienet-150 dataset [35] (where the split is not publicly available) or a private dataset: AdCuepoints [8], Wu et al. [45] have observed a similar trend as our experiments, where adding the released audio features in Movienet [18] to SCRL [45] and ShotCoL [8] drops the performance (see Tab. 5). Possible reasons can be 1) the audio features published by Movienet via STFT\\(^3\\) are an incomplete view of the shot from audio modality either in representation or in terms of the audio chunk from each shot they used, and the raw audio files are not available. 2) our multimodal fusion strategy cannot exploit the possible complementary information or filter the harmful or confusing signals from the audio modality." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.504, + 0.75, + 0.52 + ], + "angle": 0, + "content": "5. Discussion and Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.53, + 0.895, + 0.635 + ], + "angle": 0, + "content": "Limitations. The explorations in this work are limited to appearance, location, activity, acoustic and textual features. For long movie segmentation, however, providing the name of actors (tabular data) and having a specific component for actor identification in the movie can help both the synchronization and the act/scene segmentation models. We will explore the use of this data." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.636, + 0.895, + 0.772 + ], + "angle": 0, + "content": "The results demonstrated that richer semantic representations from the clip features enhanced the performance for long video segmentation. To obtain better performing representations for long video understanding one can use large amount of unlabeled data with carefully selected pretext tasks for understanding long context. We will investigate the use of SSL to train a rich multimodal representation from videos and will examine the learned representations across multiple long video understanding tasks." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.772, + 0.895, + 0.879 + ], + "angle": 0, + "content": "Conclusion. This paper introduces MEGA, a unified solution for long video segmentation. Our design of normalized positional encoding, and their integration into fusion tokens allows MEGA to learn consistent patterns from inputs with variable lengths and efficiently and effectively align and fuse them across different modalities. Our synchronization schema further allows the use of rich multimodal tokens to" + }, + { + "type": "page_footnote", + "bbox": [ + 0.076, + 0.851, + 0.472, + 0.902 + ], + "angle": 0, + "content": "2This strategy maintains the rank of probability scores for different turning points across different segments of the movie, and is consistent with the max-pooling of prediction scores on shot level to derive the scene level predictions during evaluation (see Sec. 4.2)." + }, + { + "type": "page_footnote", + "bbox": [ + 0.516, + 0.887, + 0.858, + 0.9 + ], + "angle": 0, + "content": "3https://github.com/movienet/movienet-tools" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.957 + ], + "angle": 0, + "content": "23338" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.152 + ], + "angle": 0, + "content": "be used in transferring the labels from synopsis sentences to movie shots, facilitating the knowledge distillation from synopses to movies. MEGA achieves state-of-the-art performance compared with previous works." + }, + { + "type": "title", + "bbox": [ + 0.08, + 0.164, + 0.173, + 0.179 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.189, + 0.47, + 0.229 + ], + "angle": 0, + "content": "[1] Sentence-transformers model: all-minilm-l6-v2 from Hugging Face. https://huggingface.co/sentence-transformers/all-MiniLM-L6-v2.3" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.232, + 0.472, + 0.286 + ], + "angle": 0, + "content": "[2] Yuki Asano, Mandela Patrick, Christian Rupprecht, and Andrea Vedaldi. Labelling unlabelled videos from scratch with multi-modal self-supervision. Advances in Neural Information Processing Systems, 33:4660-4671, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.089, + 0.288, + 0.471, + 0.342 + ], + "angle": 0, + "content": "[3] Yusuf Aytar, Carl Vondrick, and Antonio Torralba. Soundnet: Learning sound representations from unlabeled video. Advances in neural information processing systems, 29, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.344, + 0.471, + 0.398 + ], + "angle": 0, + "content": "[4] Lorenzo Baraldi, Costantino Grana, and Rita Cucchiara. A deep siamese network for scene detection in broadcast videos. In Proceedings of the 23rd ACM international conference on Multimedia, pages 1199-1202, 2015. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.4, + 0.471, + 0.438 + ], + "angle": 0, + "content": "[5] Jessica Brody. Save the Cat! Writes a Novel: The Last Book On Novel Writing You'll Ever Need. Ten Speed Press, 2018. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.442, + 0.471, + 0.496 + ], + "angle": 0, + "content": "[6] Joao Carreira and Andrew Zisserman. Quo vadis, action recognition? a new model and the kinetics dataset. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 6299-6308, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.498, + 0.471, + 0.551 + ], + "angle": 0, + "content": "[7] Vasileios T Chasanis, Aristidis C Likas, and Nikolaos P Galatsanos. Scene detection in videos using shot clustering and sequence alignment. IEEE transactions on multimedia, 11(1):89-100, 2008. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.553, + 0.472, + 0.621 + ], + "angle": 0, + "content": "[8] Shixing Chen, Xiaohan Nie, David Fan, Dongqing Zhang, Visual Bhat, and Raffay Hamid. Shot contrastive self-supervised learning for scene boundary detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9796-9805, 2021. 1, 2, 4, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.623, + 0.47, + 0.705 + ], + "angle": 0, + "content": "[9] Zi-Yi Dou, Yichong Xu, Zhe Gan, Jianfeng Wang, Shuohang Wang, Lijuan Wang, Chenguang Zhu, Pengchuan Zhang, Lu Yuan, Nanyun Peng, et al. An empirical study of training end-to-end vision-and-language transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18166-18176, 2022. 1, 2, 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.707, + 0.471, + 0.775 + ], + "angle": 0, + "content": "[10] Philip Gorinski and Mirella Lapata. Movie script summarization as graph-based scene extraction. In Proceedings of the 2015 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pages 1066-1076, 2015. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.777, + 0.471, + 0.87 + ], + "angle": 0, + "content": "[11] Chunhui Gu, Chen Sun, David A Ross, Carl Vondrick, Caroline Pantofaru, Yeqing Li, Sudheendra Vijayanarasimhan, George Toderici, Susanna Ricco, Rahul Sukthankar, et al. Ava: A video dataset of spatio-temporally localized atomic visual actions. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 6047-6056, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.471, + 0.901 + ], + "angle": 0, + "content": "[12] Saurabh Gupta, Judy Hoffman, and Jitendra Malik. Cross modal distillation for supervision transfer. In Proceedings of" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.189, + 0.472, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.894, + 0.12 + ], + "angle": 0, + "content": "the IEEE conference on computer vision and pattern recognition, pages 2827-2836, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.123, + 0.894, + 0.177 + ], + "angle": 0, + "content": "[13] Bo Han and Weiguo Wu. Video scene segmentation using a novel boundary evaluation criterion and dynamic programming. In 2011 IEEE International conference on multimedia and expo, pages 1-6. IEEE, 2011. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.179, + 0.894, + 0.22 + ], + "angle": 0, + "content": "[14] Michael Hauge. Storytelling Made Easy: Persuade and Transform Your Audiences, Buyers, And Clients-Simply, Quickly, and Profitably. BookBaby, 2017. 1, 2, 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.222, + 0.894, + 0.289 + ], + "angle": 0, + "content": "[15] Lisa Anne Hendricks, John Mellor, Rosalia Schneider, Jean-Baptiste Alayrac, and Aida Nematzadeh. Decoupling the role of data, attention, and losses in multimodal transformers. Transactions of the Association for Computational Linguistics, 9:570-585, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.292, + 0.893, + 0.319 + ], + "angle": 0, + "content": "[16] Dan Hendrycks and Kevin Gimpel. Gaussian error linear units (gelus). arXiv preprint arXiv:1606.08415, 2016. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.321, + 0.894, + 0.376 + ], + "angle": 0, + "content": "[17] Qingqiu Huang, Yu Xiong, and Dahua Lin. Unifying identification and context learning for person recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 2217-2225, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.379, + 0.894, + 0.433 + ], + "angle": 0, + "content": "[18] Qingqiu Huang, Yu Xiong, Anyi Rao, Jiaze Wang, and Dahua Lin. Movienet: A holistic dataset for movie understanding. In European Conference on Computer Vision, pages 709-727. Springer, 2020. 2, 5, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.435, + 0.894, + 0.502 + ], + "angle": 0, + "content": "[19] Andrew Jaegle, Felix Gimeno, Andy Brock, Oriol Vinyals, Andrew Zisserman, and Joao Carreira. Perceiver: General perception with iterative attention. In International conference on machine learning, pages 4651-4664. PMLR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.505, + 0.894, + 0.572 + ], + "angle": 0, + "content": "[20] Prannay Khosla, Piotr Teterwak, Chen Wang, Aaron Sarna, Yonglong Tian, Phillip Isola, Aaron Maschinot, Ce Liu, and Dilip Krishnan. Supervised contrastive learning. Advances in Neural Information Processing Systems, 33:18661-18673, 2020. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.576, + 0.894, + 0.63 + ], + "angle": 0, + "content": "[21] Wonjae Kim, Bokyung Son, and Ildoo Kim. Vilt: Vision-and-language transformer without convolution or region supervision. In International Conference on Machine Learning, pages 5583-5594. PMLR, 2021. 1, 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.633, + 0.894, + 0.672 + ], + "angle": 0, + "content": "[22] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.676, + 0.894, + 0.744 + ], + "angle": 0, + "content": "[23] Qiuqiang Kong, Yin Cao, Turab Iqbal, Yuxuan Wang, Wenwu Wang, and Mark D Plumbley. Panns: Large-scale pretrained audio neural networks for audio pattern recognition. IEEE/ACM Transactions on Audio, Speech, and Language Processing, 28:2880-2894, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.747, + 0.894, + 0.814 + ], + "angle": 0, + "content": "[24] Shengjie Luo, Shanda Li, Tianle Cai, Di He, Dinglan Peng, Shuxin Zheng, Guolin Ke, Liwei Wang, and Tie-Yan Liu. Stable, fast and accurate: Kernelized attention with relative positional encoding. Advances in Neural Information Processing Systems, 34:22795-22807, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.817, + 0.894, + 0.87 + ], + "angle": 0, + "content": "[25] Rada Mihalcea and Paul Tarau. Textrank: Bringing order into text. In Proceedings of the 2004 conference on empirical methods in natural language processing, pages 404-411, 2004. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.873, + 0.894, + 0.901 + ], + "angle": 0, + "content": "[26] Paramita Mirza, Mostafa Abouhamra, and Gerhard Weikum. Alignnarr: Aligning narratives on movies. In The 59th Annual" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.946, + 0.519, + 0.957 + ], + "angle": 0, + "content": "23339" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.134 + ], + "angle": 0, + "content": "Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing, pages 427-433. ACL, 2021. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.137, + 0.472, + 0.192 + ], + "angle": 0, + "content": "[27] Jonghwan Mun, Minchul Shin, Gunsoo Han, Sangho Lee, Seongsu Ha, Joonseok Lee, and Eun-Sol Kim. Boundary-aware self-supervised learning for video scene segmentation. arXiv preprint arXiv:2201.05277, 2022. 2, 3, 4, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.195, + 0.472, + 0.249 + ], + "angle": 0, + "content": "[28] Arsha Nagrani, Shan Yang, Anurag Arnab, Aren Jansen, Cordelia Schmid, and Chen Sun. Attention bottlenecks for multimodal fusion. Advances in Neural Information Processing Systems, 34:14200-14213, 2021. 2, 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.252, + 0.472, + 0.321 + ], + "angle": 0, + "content": "[29] Pinelopi Papalampidi, Frank Keller, Lea Frermann, and Mirella Lapata. Screenplay summarization using latent narrative structure. In Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics, pages 1920-1933, 2020. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.324, + 0.472, + 0.366 + ], + "angle": 0, + "content": "[30] Pinelopi Papalampidi, Frank Keller, and Mirella Lapata. Movie plot analysis via turning point identification. arXiv preprint arXiv:1908.10328, 2019. 1, 2, 3, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.368, + 0.472, + 0.409 + ], + "angle": 0, + "content": "[31] Pinelopi Papalampidi, Frank Keller, and Mirella Lapata. Film trailer generation via task decomposition. arXiv preprint arXiv:2111.08774, 2021. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.412, + 0.472, + 0.467 + ], + "angle": 0, + "content": "[32] Pinelopi Papalampidi, Frank Keller, and Mirella Lapata. Movie summarization via sparse graph construction. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 13631-13639, 2021. 1, 2, 4, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.47, + 0.472, + 0.498 + ], + "angle": 0, + "content": "[33] Patrice Pavis. Dictionary of the theatre: Terms, concepts, and analysis. University of Toronto Press, 1998. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.501, + 0.472, + 0.583 + ], + "angle": 0, + "content": "[34] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning, pages 8748-8763. PMLR, 2021. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.586, + 0.472, + 0.668 + ], + "angle": 0, + "content": "[35] Anyi Rao, Linning Xu, Yu Xiong, Guodong Xu, Qingqiu Huang, Bolei Zhou, and Dahua Lin. A local-to-global approach to multi-modal movie scene segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10146-10155, 2020. 1, 2, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.672, + 0.472, + 0.712 + ], + "angle": 0, + "content": "[36] Zeeshan Rasheed and Mubarak Shah. Detection and representation of scenes in videos. IEEE transactions on Multimedia, 7(6):1097-1105, 2005. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.716, + 0.472, + 0.77 + ], + "angle": 0, + "content": "[37] Daniel Rotman, Dror Porat, and Gal Ashour. Optimal sequential grouping for robust video scene detection using multiple modalities. International Journal of Semantic Computing, 11(02):193-208, 2017. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.774, + 0.472, + 0.855 + ], + "angle": 0, + "content": "[38] Peter Shaw, Jakob Uszkoreit, and Ashish Vaswani. Self-attention with relative position representations. In Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 2 (Short Papers), pages 464–468, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.859, + 0.472, + 0.901 + ], + "angle": 0, + "content": "[39] Tomáš Souček and Jakub Lokoc. Transnet v2: an effective deep network architecture for fast shot transition detection. arXiv preprint arXiv:2008.04838, 2020. 1, 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.472, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[40] Jianlin Su, Yu Lu, Shengfeng Pan, Bo Wen, and Yunfeng Liu. Roformer: Enhanced transformer with rotary position embedding. arXiv preprint arXiv:2104.09864, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.137, + 0.894, + 0.19 + ], + "angle": 0, + "content": "[41] Makarand Tapaswi, Martin Bauml, and Rainer Stiefelhagen. Storygraphs: visualizing character interactions as a timeline. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 827-834, 2014. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.193, + 0.894, + 0.247 + ], + "angle": 0, + "content": "[42] Makarand Tapaswi, Martin Bäuml, and Rainer Stiefelhagen. Aligning plot synopses to videos for story-based retrieval. International Journal of Multimedia Information Retrieval, 4(1):3-16, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.249, + 0.894, + 0.304 + ], + "angle": 0, + "content": "[43] Makarand Tapaswi, Martin Bauml, and Rainer Stiefelhagen. Book2movie: Aligning video scenes with book chapters. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1827-1835, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.305, + 0.894, + 0.36 + ], + "angle": 0, + "content": "[44] Yikai Wang, Wenbing Huang, Fuchun Sun, Tingyang Xu, Yu Rong, and Junzhou Huang. Deep multimodal fusion by channel exchanging. Advances in Neural Information Processing Systems, 33:4835-4845, 2020. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.362, + 0.894, + 0.444 + ], + "angle": 0, + "content": "[45] Haoqian Wu, Keyu Chen, Yanan Luo, Ruizhi Qiao, Bo Ren, Haozhe Liu, Weicheng Xie, and Linlin Shen. Scene consistency representation learning for video scene segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14021-14030, 2022. 2, 4, 5, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.446, + 0.894, + 0.514 + ], + "angle": 0, + "content": "[46] Saining Xie, Ross Girshick, Piotr Dólar, Zhuowen Tu, and Kaiming He. Aggregated residual transformations for deep neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1492-1500, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.517, + 0.894, + 0.584 + ], + "angle": 0, + "content": "[47] Yu Xiong, Qingquiu Huang, Lingfeng Guo, Hang Zhou, Bolei Zhou, and Dahua Lin. A graph-based framework to bridge movies and synopses. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4592-4601, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.587, + 0.894, + 0.657 + ], + "angle": 0, + "content": "[48] Ning Zhang, Manohar Paluri, Yaniv Taigman, Rob Fergus, and Lubomir Bourdev. Beyond frontal faces: Improving person recognition using multiple cues. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4804-4813, 2015. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.657, + 0.894, + 0.755 + ], + "angle": 0, + "content": "[49] Chao Zhao, Wenlin Yao, Dian Yu, Kaiqiang Song, Dong Yu, and Jianshu Chen. Learning-by-narrating: Narrative pretraining for zero-shot dialogue comprehension. In Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers), pages 212-218, Dublin, Ireland, May 2022. Association for Computational Linguistics. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.757, + 0.894, + 0.811 + ], + "angle": 0, + "content": "[50] Bolei Zhou, Agata Lapedriza, Aditya Khosla, Aude Oliva, and Antonio Torralba. Places: A 10 million image database for scene recognition. IEEE transactions on pattern analysis and machine intelligence, 40(6):1452-1464, 2017. 3, 6" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.811 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.946, + 0.52, + 0.957 + ], + "angle": 0, + "content": "23340" + } + ] +] \ No newline at end of file diff --git a/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/014aa68e-4ee6-4ed7-996a-a0fac673a258_origin.pdf b/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/014aa68e-4ee6-4ed7-996a-a0fac673a258_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..f4755dd53641df13166fe35edcf8ba661819c5c5 --- /dev/null +++ b/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/014aa68e-4ee6-4ed7-996a-a0fac673a258_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:5ccb1af323776f56714e63d9c13730b8ad383719b4fd0c6ae36db390f95d15c6 +size 529739 diff --git a/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/full.md b/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/full.md new file mode 100644 index 0000000000000000000000000000000000000000..31cd6eba0c9eb2beb8adaca5c94ae8f91d595604 --- /dev/null +++ b/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/full.md @@ -0,0 +1,319 @@ +# MEGA: Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation + +Najmeh Sadoughi1, Xinyu Li1, Avijit Vajpayee1, David Fan1, Bing Shuai2, Hector Santos-Villalobos1, Vimal Bhat1, Rohith MV1 +1Amazon Prime Video, 2AWS AI Labs + +{nnnourab,xxnl,avivaj,fandavi,bshuai,hsantosv,vimalb,kurohith}@amazon.com + +# Abstract + +Previous research has studied the task of segmenting cinematic videos into scenes and into narrative acts. However, these studies have overlooked the essential task of multimodal alignment and fusion for effectively and efficiently processing long-form videos ( $>60\mathrm{min}$ ). In this paper, we introduce Multimodal alignmEnt aGgregation and distillAtion (MEGA) for cinematic long-video segmentation. MEGA tackles the challenge by leveraging multiple media modalities. The method coarsely aligns inputs of variable lengths and different modalities with alignment positional encoding. To maintain temporal synchronization while reducing computation, we further introduce an enhanced bottleneck fusion layer which uses temporal alignment. Additionally, MEGA employs a novel contrastive loss to synchronize and transfer labels across modalities, enabling act segmentation from labeled synopsis sentences on video shots. Our experimental results show that MEGA outperforms state-of-the-art methods on MovieNet dataset for scene segmentation (with an Average Precision improvement of $+1.19\%$ ) and on TRI-POD dataset for act segmentation (with a Total Agreement improvement of $+5.51\%$ ). + +# 1. Introduction + +In the world of video production, movies are composed of smaller units called shots, scenes, and acts. Shots are a continuous set of frames, a scene is a sequence of shots that tell a story, and an act is a thematic section of a narrative [14]. While computer vision has made significant strides in shot detection [39], scene and act segmentation remain a challenge, despite their potential for smart video navigation, advertisement insertion, and movie summarization. Cinematic content comprises of different data sources, including audio, visual, and text data, as well as derivative data sources from the narrative, including location, appearance, tone, or acoustic events. In this work, we will refer to all of these + +![](images/0006a7d310399a74f432bb3da97e518fc571bd114cbb9fb6c04e4fff1ad472ba.jpg) +Figure 1: MEGA works well on both scene segmentation and act segmentation tasks, outperforming previous work with significant margin. V,T*,T,A denotes video, screenplay, subtitle and audio respectively. + +input components as "modalities" of cinematic content. Previous work has not fully explored how to align and aggregate these modalities which have different granularities. + +We propose to address scene and act segmentation tasks with an unified multimodal Transformer. However, this approach presents two main challenges. Firstly, there is the issue of cross modality information synchronization and fusion at the shot level. Previous studies which use multimodal fusion for scene and act segmentation perform early [8, 32] or late fusion of features [35], and have not explored fusion strategies which utilize multimodal temporal alignment. Additionally, the fusion strategies that utilize temporal alignment such as merged attention or cross modality attention [9, 21] are computationally expensive and not generalizable to a large number of modalities. Secondly, due to the challenges associated with labeling a long video on act segmentation, the labels for act segmentation are provided on synopsis sentences [30] which do not provide timestamps. To avoid the more challenging task of cross-modal synchronization, previous studies on act segmentation [30, 32] rely + +on textual screenplay to transfer the labels from synopsis to movie, ignoring the rich multimodal information from the video, and introducing an additional dependency on screenplay data which is not always available. + +To address these challenges, we introduce Multimodal alignmEnt aGgregation and distillation (MEGA). MEGA includes a novel module called alignment positional encoding which aligns inputs of variable lengths and different modalities at a coarse temporal level. To fuse the aligned embeddings of different modalities in an efficient and effective manner, we adopt the bottleneck fusion tokens [28] and append a set of fusion tokens to each modality. These tokens share the same sequence length as the normalized positional encoding for different modalities, allowing us to inject them with the coarse temporal information, enabling information fusion in a better aligned embedding space. To address the issue of cross-domain knowledge transfer, we introduce a cross-modal synchronization approach. This method allows us to transfer the manually labeled act boundaries from synopsis level to movie level using rich multimodal information, enabling us to train MEGA directly on videos without relying on screenplay – which was a hard requirement for previous works [30, 32]. + +We test our proposed alignment and aggregation modules on the Movienet-318 [18] and the TRIPOD datasets [30], and we test our cross modality synchronization module on TRIPOD alone, as the labels are provided on a different modality during training. Our proposed MEGA outperforms previous SoTA on scene segmentation on the Movienet-318 dataset (by $+1.19\%$ in AP) and on act segmentation on the TRIPOD dataset (by $+5.51\%$ in TA). Our contributions are: + +1. Alignment positional encoding module and a fusion bottleneck layer that performs multimodal fusion with aligned multi-modality inputs. +2. A cross-domain knowledge transfer module that synchronizes features across-domain, and enables knowledge distillation without requiring extra information. +3. SoTA performance on scene and act segmentation tasks, with detailed ablations, which can be used as reference for future work. + +# 2. Related Work + +Scene Segmentation in Cinematic Content: Recent works on scene segmentation have explored self-supervised learning (SSL) [8,27,45]. Self-supervised pretext tasks have included maximizing the similarity between nearby shots compared to randomly selected ones [8], maximizing the similarity between pairs of images selected according to scene consistency [45], and maximizing the similarity between pairs of images selected according to pseudo scene boundaries [27]. While several previous works have used multimodal inputs for this task [8,35,45], they have either utilized late fusion of features with predefined weights for each + +modality [35] or have utilized early integration of features derived via SSL [8, 45]. In this paper, we explore how to better align and integrate features from different modalities for scene segmentation. + +Act Segmentation in Cinematic Content: Movie screenplays follow a general narrative structure on how a plot unfolds across the story. Several theories have been proposed in this domain dating as far back as Aristotle, who defined a 3 act structure with a beginning (protasis), middle (epitasis), and end (catastrophe) [33]. Modern screenplays are usually written with a 6 act structure [14], named as "the setup", "the new situation", "progress", "complications and higher stakes", "the final push", and "the aftermath", separated by five turning points (TPs). Prior approaches in narrative segmentation on movies have adopted the aforementioned 6 act structure and posed the problem as identifying the 5 TPs that separate these 6 acts. [32] is to our knowledge the only prior work that utilizes visual domain in act segmentation by using a pre-trained teacher model trained on textual input to train a student Graph Convolutional network with audio-visual-text representations as input. In contrast, our work uses a new multimodal fusion and distillation applied on the modalities which are available with the movie. + +Multimodal Aggregation: Previous SoTAs on multimodal fusion with transformers perform early fusion of the features as inputs to the transformer [19], merge attention between them requiring more memory [9,21], use cross attention between two modalities [9,44], or add cross-modal interactions more efficiently via bottleneck tokens or exchanging some of their latents [15, 28]. [28] provides information flow between modalities efficiently by utilizing bottleneck tokens to tame the quadratic complexity of pairwise attention. This global exchange between modalities may not be enough for long videos, which require an adaptive fusion in different temporal locations. Our model considers [28] as baseline and extends it to incorporate local information during information exchange between modalities. + +Positional Encoding: Previous studies on improving the positional encoding in long sequence modeling have mostly focused on adding relative distance positional encoding [24, 38, 40]. However, they do not offer solutions on better maintaining the relative position of latent tokens with respect to their starting point in time in long sequences with variable lengths, which is important for long movie narrative understanding [5, 14]. We propose Alignment Positional Encoding to bridge this gap. + +Cross-Modality Synchronization & Distillation: To transfer the labels from synopsis to movie shots, we use cross-modality distillation. Previous cross-modality distillation studies for label transfer across modalities are focused on parallel data with the same granularity [2,3,12], or where the alignment is known [31]. Alignment of features at different granularities in the same modality, such as screenplay + +scenes to synopsis sentences [26, 49] and across modalities such as aligning synopsis sentences to visual shots [42, 47], book chapters to visual scenes [43] have been previously explored. While majority of these works rely on unsupervised optimization techniques [26, 42, 43, 49], there are studies that use supervised labels to improve the representations used for optimization [47]. We present an alignment approach with self-supervised loss for synchronizing data in different modalities of cinematic content to enable distillation. + +# 3. Methodology + +MEGA processes long videos and performs video segmentation in three major steps (Fig. 2). First, a video $V$ is chunked into shots, and multiple features such as scene related features and sound event features are extracted at the shot-level (Sec. 3.1). The system is built on shot-level representation for two reasons: (1) scene and act boundaries always align with shot boundaries, and (2) the content within a shot remains similar, which allows efficient yet meaningful sampling without losing important information. Second, the embeddings from different input samples and each modality are coarsely aligned with a proposed alignment embedding (Sec. 3.2), and the alignment positional tokens are used to refine the commonly used bottleneck fusion tokens for cross-modal feature fusion (Sec. 3.2). Third, a linear layer is applied on top of the fused representations to generate scene and act boundaries (Sec. 3.3). Finally, to address the challenge of cross-domain knowledge transfer where labels from one domain may not directly align with another domain (e.g. act labels on synopsis sentences do not have movie-level timing information), we propose a cross-modal synchronization module that is simple yet effective (Sec. 3.4). + +# 3.1. Preprocessing + +We chose to utilize Transnet-v2 [39] for shot segmentation due to its superior performance and efficiency. We list our selection of pre-trained models and associated parameters in Tab. 1. As each pretrained feature extraction model has different requirements for input resolution and sampling rate, we first sample the input at various sample rates (as shown in Table 1). It is worth noting that the $\mathrm{CLIP}_{\mathrm{movie}}$ model is the CLIP [34] model with ViT-B/32 backbone fine-tuned on paired IMDB-image/text dataset. IMDB-image dataset comprises 1.6M images from 31.3K unique movies/TV series with 761 unique textual labels. The features attributed to each shot are the ones with overlap with the shot time stamp (More details are in Appendix). After feature extraction, we aggregate the features for each shot and normalize the feature dimension with linear projection as: + +$$ +E _ {i} ^ {m} = g ^ {m} \left(\frac {1}{T _ {i} ^ {m}} \sum_ {j = 1} ^ {T _ {i} ^ {m}} S _ {i j} ^ {m}\right) \tag {1} +$$ + +
Feature extractorInput Freq.Input Res.Feature dim.
Visual input
BASSL [27] (bassi)Varying22422048
ResNetPlace [50] (place)1Hz22422048
ResNeXt101 [46] (appr)1Hz22422048
I3D [6] (action)16Hz16 × 22422048
CLIPmovie (clip)1Hz2242768
Acoustic input
PANNs [23] (audio)1Hz10 × 32K2048
Linguistic input
all-MiniLM-L6-v2 [1] (text)Varying-384
+ +Table 1: Sampling strategy and feature extraction backbones used for different modalities. + +where $E_{i}^{m}\in \mathbb{R}^{C}$ denotes the embedding from the $i$ -th shot of $m$ -th modality, $S_{ij}^{m}\in \mathbb{R}^{D^{m}}$ is the $j$ -th sampled feature of $m$ -th modality from $i$ -th shot, and $g^{m}$ is a linear projection layer that projects feature dimension for $m$ -th modality to a common dimension $C$ across all modalities. + +While it is possible to create an end-to-end system starting from raw shot inputs and training the model from scratch, pre-extracting the features from pretrained models is generally more scalable and efficient in actual industrial scenarios, hence we rely on the latter. + +# 3.2. Cross-modality Alignment and Fusion + +For long video segmentation into scenes and acts it is important to model short and long term context and perform effective multimodal fusion. However, the commonly used learnable positional embedding only provides fine-grained granularity and is not suitable for high-level semantic alignment across modalities. Furthermore, for tasks such as act segmentation we expect consistent patterns at normalized position of temporal inputs as the theory suggests approximate locations for each turning point (i.e., $10\%$ , $25\%$ , $50\%$ , $75\%$ , $95\%$ [5, 14, 30]). Hence, in addition to using the traditional positional encoding, we introduce Alignment Positional Encoding layer $\in \mathbb{R}^{L_n\times C}$ , which is a learnable embedding layer, for which the index at $i$ -th temporal unit (e.g., shot) is derived by: + +$$ +i _ {\text {a l i g n}} = \operatorname {f l o o r} \left(\frac {L _ {n}}{L} i\right) \tag {2} +$$ + +where $L$ is the temporal dimension (e.g., number of shots) and $L_{n}$ is the length of alignment positional encoding which is a hyper-parameter $(L_{n} < L)$ . We add the alignment positional encoding to the features in conjunction with the conventional positional encoding (see Fig 2). This module is shared across different modalities. This module provides extra information to the network that can be helpful in learning from long training samples with varying lengths, and in coarsely aligning inputs from different modalities before information fusion. + +Inspired by previous works [9, 28, 44], we choose cross-modal feature fusion, which has been shown to be more effective than early or late fusion. To make our approach scale to + +![](images/b4c1fa0eab68f6677ce713b7eeb86c344366a1b3b7e448da08c09fa934e934a8.jpg) +Figure 2: The pipeline of the proposed method includes 1) Preprocessing: splitting the video into shots, extraction of features from each shot, pooling and normalization 2) Cross modality fusion and alignment: with the help of alignment positional encoding and bottleneck fusion tokens, 3) Scene/Act Segmentation comprising the segmentation heads. For Scene Segmentation, CE loss is used and for Act Segmentation knowledge transfer loss is used (refer to Sec. 3.4 for details) + +multiple modalities, we propose an efficient temporal bottleneck fusion based on [28], and follow their mid-fusion strategy, which comprises of an unimodal transformer encoder followed by a multimodal transformer encoder (See Fig. 2). While [28] proposes to use bottleneck tokens for fusing information across different modalities, these tokens learn to integrate the information across modalities in a global manner. We propose to use $L_{n}$ fusion tokens, and then integrate them with the same Normalized Positional Encoding to align them with features on the coarse temporal scale (Fig. 3). + +The transformer layer per modality then takes in an extra set of aligned fusion tokens concatenated with its input (Fig 2), making it much more efficient compared to other methods such as merged attention or pairwise cross-attention with respect to the number of modalities [9, 21]. Finally, the latent tokens per modality from the last fusion layer (i.e., $Z^{m}$ for m-th modality) are concatenated as the fused representation: + +$$ +Z ^ {\text {f u s e d}} = \operatorname {c o n c a t} _ {C} (Z) = \operatorname {c o n c a t} _ {C} \left(\left[ Z ^ {1}, \dots , Z ^ {M} \right]\right) \tag {3} +$$ + +where $\mathrm{concat}_C(*)$ stands for channel-wise concatenation and $M$ is the number of modalities. + +# 3.3. Scene/Act Segmentation + +MEGA adopts a similar approach to previous works [8, 27, 45], where scene segmentation is framed as a binary classification task using a key-shot representation from a window of $2 \times k + 1$ shots ( $k$ -shots before and after): + +$$ +y _ {i} = \varphi \left(Z _ {i} ^ {\text {f u s e d}}; \theta_ {s}\right) \tag {4} +$$ + +where $y_{i}$ is the logit prediction for the $i$ -th key-shot. $\varphi$ denotes the linear layer with learnable parameters $\theta_{s}$ and a cross entropy loss is utilized [8, 27, 45]. + +![](images/38230f068fb726688e8efa1c12e99c38d33284de129a5743fdc87fdd883bef7d.jpg) +Figure 3: Illustration of Normalized Positional Encoding integration to the temporal tokens in one modality. This figure shows the integration of normalized Positional Encoding with 1) temporal shots for one modality and 2) bottleneck fusion tokens, where $L = 15$ and $L_{n} = 3$ . For (1) $i_{\text{align}}$ is obtained per shot index, $i$ , and then each shot is integrated with normalized PE. For (2) each randomly initialized bottleneck token is integrated with normalized PE for its corresponding index. + +The act segmentation task is formulated as $N_{tp}$ linear prediction heads ( $N_{tp}$ is the number of turning points, and $\theta_{a_n}$ denotes the head parameters for $n$ -th turning point [32]), for each individual shot from a temporal model that takes all the shots of the movie as input. To make a prediction at the $i$ -th shot for the $n$ -th act boundary ( $n \in \{1, \dots, N_{tp}\}$ ), we use: + +$$ +y _ {i n} = \varphi \left(Z _ {i} ^ {\text {f u s e d}}; \theta_ {a _ {n}}\right) \tag {5} +$$ + +where $y_{in}$ is the logit prediction for $i$ -th shot and $n$ -th turning point. + +# 3.4. Cross-domain Knowledge Transfer + +It is quite common during machine learning that certain modalities may lack annotations that are directly available in other modalities with different information granularity. To address this, we propose a cross-modality synchronization scheme that enables cross-modal distillation. We utilize this module for act segmentation where we aim to transfer act labels from synopsis sentences to movie-level timestamps. Importantly, our approach does not require additional information, such as screenplay [32], to bridge the gap. + +Our knowledge distillation utilizes (1) an individual network to learn the synopsis-based act segmentation in a supervised manner with cross-entropy loss similar to [31]; and (2) a novel synchronization approach between synopsis and movie. For (1) we use the same architecture mentioned in Secs. 3.1, 3.2, setting $C_{\mathrm{fused}}$ equal to the multimodal shot model setting. Additionally, similar to shot level linear prediction head (See Eq. 5), we use a sentence level linear prediction head, resulting in $q_{in}$ logits for the $i$ -th sentence of $n$ -th TP. A supervised Cross Entropy loss is used to learn the synopsis labels from predictions for each turning point $(\mathcal{L}_{ce})$ . For (2) we seek a synchronization matrix $W \in \mathbb{R}^{L_{sh} \times L_{syn}}$ between $L_{sh}$ shots and $L_{syn}$ synopsis sentences for a sample, where $w_{ij} = 1$ if the $i$ -th shot matches with the $j$ -th synopsis sentence and $w_{ij} = 0$ , otherwise. Assuming $F(:, \theta)$ represents a parametric reward function (with parameters $\theta$ ), to find $W$ , we define an objective as: + +$$ +\max _ {W, \theta} \sum_ {i, j} w _ {i j} F (.; \theta) - \lambda \sum_ {i, j} | w _ {i, j} | \tag {6} +$$ + +$$ +s. t. 0 \leq w _ {i j} \leq 1 +$$ + +Expectation-Maximization algorithm is used to solve the objective in Eq. 6. We estimate the target variable $W$ via fixed parameters (i.e., $\theta$ ) in the E-step, and update the parameters while the target variable is known in the M-step. + +E-step: Assuming $F(:,\theta)$ returns the similarity of input shot and synopsis sentence pair, the E-step has a closed form solution. In the E-step, following [26], we reduce the search space during optimization to only the pairs which are inside a diagonal boundary (see the proof for E-step and visualization of expected synchronization matrix for different examples in Appendix). + +M-step: Using all samples in a batch with $L_{\mathrm{SH}}$ , $L_{\mathrm{SYN}}$ total number of shots and synopsis sentences, we form their cosine similarity matrix of dimension $L_{\mathrm{SH}} \times L_{\mathrm{SYN}}$ . For each query (synopsis sentence/movie shot, respectively), the positive keys (movie shot/synopsis sentence, respectively) are derived from the expectation step. Negative keys are the keys lying outside the diagonal boundary of the similarity matrix of shot-synopsis pairs for one movie [26], and all the keys from other movies within the batch. Here each query (synopsis sentence/movie shot, respectively) can have more than one + +positive key (movie shot/synopsis sentence, respectively) attached to it. Following [20], we adopt a modified version of the InfoNCE loss and combine it with the symmetric contrastive loss [34] as: + +$$ +\begin{array}{l} \mathcal {L} _ {c} = - \sum_ {i = 1} ^ {L _ {\mathrm {S Y N}}} \frac {1}{| \hat {y} _ {i} |} \sum_ {k = 1} ^ {L _ {\mathrm {S H}}} \hat {y} _ {i k} \log \frac {\exp \left(v _ {i} u _ {k} / \tau\right)}{\sum_ {j = 1} ^ {L _ {\mathrm {S H}}} \exp \left(v _ {i} u _ {j} / \tau\right)} - \tag {7} \\ \sum_ {i = 1} ^ {L _ {\mathrm {S H}}} \frac {1}{| \hat {y} _ {i} ^ {T} |} \sum_ {k = 1} ^ {L _ {\mathrm {S Y N}}} \hat {y} _ {i k} ^ {T} \log \frac {e x p (u _ {i} v _ {k} / \tau)}{\sum_ {j = 1} ^ {L _ {\mathrm {S Y N}}} e x p (u _ {i} v _ {j} / \tau)} \\ \end{array} +$$ + +where $\tau$ is a learnable temperature parameter, and $\hat{y}_{ij}$ is a binary indicator of positive vs. negative pairs, $u_{i}$ is the normalized feature for the $i$ -th shot and $v_{i}$ is the normalized feature for the $i$ -th synopsis sentence. + +Knowledge distillation: Knowledge distillation is used to transfer the knowledge available for the training samples on synopsis. The predictions from the synopsis model are mapped to shots using a matrix of their similarities as calculated in the maximization step, for each sample. The similarity scores for each shot are normalized along the synopsis sentences with softmax. The logit predictions from synopsis model are transferred to shots by multiplication with the normalized similarity matrix. A softmax along the shots is applied to the transferred logits to derive the probability scores for each shot. Following [31], we use a Kullback-Leibler divergence loss between predicted outputs for each shot and the transferred probabilities $(\mathcal{L}_{kd})$ (More details are provided in Appendix.). + +The cross-domain knowledge transfer module can be trained by simply adding the losses together as: + +$$ +\mathcal {L} = \alpha_ {c} \mathcal {L} _ {c} + \alpha_ {c e} \mathcal {L} _ {c e} + \alpha_ {k d} \mathcal {L} _ {k d} \tag {8} +$$ + +where $\alpha_{c},\alpha_{ce}$ , and $\alpha_{kd}$ are hyperparameters that control the weights of the three losses. + +# 4. Experiments + +# 4.1. Dataset + +We test our model on two commonly used dataset: Movienet-318 [18]: consists of 1100 movies, out of which 318 movies are annotated for the task of scene segmentation. The annotated dataset is split into 190, 64, and 64 movies for train, validation and test splits, respectively. We report the Average Precision (AP) and F1-score (F1) on the test split following previous work [35, 45]. + +TRIPOD [32] includes 122 movies, split into 84, and 38 movies for train and test, respectively. This dataset includes the annotations of 6 act boundaries ("the setup", "the new situation", "progress", "complications and higher stakes", "the final push", "the aftermath") on the movie synopsis sentences for the training set, and on the movie screenplay scenes for the test set. The authors also have released soft + +probability scores (silver annotations) for the training set, using $[30]^1$ . To find the timestamps for the screenplay scenes in the movie, following [32] we used Dynamic Time Warping (DTW) to align the timed subtitles from the movie to the monologue lines in the screenplay. Following [32], we use total agreement (TA), partial agreement (PA) and distance (D) as evaluation metrics. + +# 4.2. Implementation Details + +For scene segmentation: We train our model with 8 V100 GPUs with total batch size of 1024. The Adam [22] optimizer is used with learning rate of 1e-4. We train the model for 20 epochs. GeLU [16] is used as activation function by default, we use weighted cross entropy to balance the positive and negative samples at batch level. We choose shot sequence length of $17(k = 8)$ following [27]. We set $L_{n} = 2$ for this model. + +For act segmentation: We train our model with 4 V100 GPUs with total batch size of 4. The SGD optimizer is used with learning rate of 1e-3. We train the model for 10 epochs. $\lambda$ in Eq. 6 is empirically set differently for each synopsis sentence of each sample, by finding $99\%$ percentile of the similarity scores between the synopsis sentence and all the shots corresponding to that sample. $\alpha_{c}, \alpha_{ce}, \alpha_{kd}$ are set to 1, 1, and 10. We set $L_{n} = 100$ for this the shot model and $L_{n} = 20$ for the synopsis model. We use max pooling to aggregate the shot-level predictions to scene level. We use all shots from a video for act segmentation. + +# 4.3. Main Results + +SoTA on Scene Segmentation. We first show MEGA outperforms previous SoTA on MovieNet318 [27] for scene segmentation $(+1.19\%)$ on AP and $+8.28\%$ on F1). With the same input visual features, MEGA outperforms previous SoTA [27] (Tab. $2 + 0.52\%$ on AP and $+3.69\%$ on F1), which indicates that the proposed approach is effective. Thanks to the proposed cross-modality fusion module, the MEGA generalizes and benefits from additional information extracted from visual signals. MEGA with 3 visual modalities (clip, place, and bassl) outperforms single modality model by $+0.67\%$ on AP and $+4.59\%$ on F1, which shows the proposed fusion works as expected. It is worth mentioning that the proposed method is scalable and generalizes to various number of modalities at different scales, which makes it flexible for real-world applications. + +SoTA on Act Segmentation. We then show that MEGA establishes the new SoTA performance on act segmentation on TRIPOD dataset (Tab. 3). We first show that MEGA outperforms previous SoTA on TRIPOD [32] dataset With only visual signals as input. Comparing to other works that take textural inputs [29, 32], MEGA is able to achieve better performance. Furthermore, in real-world applications, the + +
ApproachModalityPretrained onAP↑ [%]FI↑ [%]
Random [35]--8.2-
Visual only input
GraphCut [36]VPlaces [50]14.1-
SCSA [7]VPlaces [50]14.7-
DP [13]VPlaces [50]15.5-
Grouping [37]VPlaces [50]17.6-
StoryGraph [41]VPlaces [50]25.1-
Siamese [4]VPlaces [50]28.1-
LGSS [35]VPlaces [35]39.0-
LGSS [35]VCast [17,48]15.9-
LGSS [35]VAction [11]32.1-
ShotCoL [8]†VMovienet [18]52.8949.17
SCRL [45]VMovienet [18]54.8251.43
BaSSL [27]VMovienet [18]57.447.02
MEGAVMovienet [18]57.9250.71
MEGAVM+P+I58.5955.30
+ +Table 2: Scene boundary detection: comparison with SoTA. $\dagger$ means the numbers are copied from [45]. M+P+I denotes pre-trained on Movienet [18], Places [50] and IMDB. + +visual input (the video) is often easier to obtain than textual inputs such as screenplay [32]. We further show that MEGA* (Tab. 3), which swaps our synchronization module to use similar synchronization as SoTA [32], outperforms GRAPHTP, which demonstrates the effectiveness of proposed approach including the alignment and fusion modules. It is worth mentioning that, with multiple features extracted from visual media modality alone, MEGA outperforms previous SOTA which makes the proposed model applicable for real-world scenarios, as it is usually harder to get additional media modalities (e.g., screenplay) which are used in other works. + +By further aggregating the results from text input, MEGA establishes the new state-of-the-art on TRIPOD dataset (Tab. 3). MEGA almost doubles the performance of previous work [29, 32] with $+5.51\%$ TA, $+9.15\%$ PA, $-\%0.81$ D. This shows the proposed multimodal fusion scales and generalizes well to multiple modalities. The cross-modality distillation also works robustly for various settings. We noticed that adding the acoustic features is not always helpful to the performance (Tab. 3), probably because acoustic information provides redundant or not useful information for the task of act boundary segmentation. + +# 4.4. Ablations + +We perform ablations to examine the effectiveness of major building blocks of MEGA. We use features extracted from visual media modality (for scene segmentation: clip, place, Bassl and for act segmentation: clip, appr, action, place), with the proposed normalized positional encoding, multi-modality bottleneck fusion, and cross-modality synchronization by default unless specified. The training and evaluation follows same protocols as mentioned in Sec. 4.3. Alignment Positional Encoding. We report the ablations on Alignment PE in Tab. 4a. We notice that the proposed + +
ApproachModalityModality for synch.TA↑ [%]PA↑ [%]D↓ [%]
Random (Evenly dist.) [32]-T*4.826.9512.35
Theory [14, 30]-T*4.416.3211.03
Distribution position [32]-T*5.597.3710.74
Single modality input
TEXTRANK [25]T*T*6.1810.0017.77
SCENESUM [10]T*T*4.417.8916.86
TAM [29]T*T*7.949.479.42
GRAPHTP [32]T*T*6.7610.009.62
MEGA*VT*10.5114.548.98
MEGAVV13.9320.729.19
Multi-modality input
TEXTRANK [25]T*+A+VT*6.1810.0018.90
SCENESUM [10]T*+A+VT*6.7611.0518.93
TAM [29]T*+A+VT*7.3610.0010.01
GRAPHTP [32]T*+A+VT*9.1212.639.77
MEGA*T+VT*11.1415.208.96
MEGAT+VT+V14.6321.788.96
MEGA*T+A+VT*10.0014.088.96
MEGAT+A+VT+A+V14.1922.109.68
+ +alignment PE consistently improves the performance on both scene and act segmentation tasks, while act segmentation benefits more significantly from it. This is because of two reasons: 1) inputs to the act segmentation model have variable lengths (all the shots from a video) as opposed to scene segmentation which has fixed length inputs, hence the alignment PE adds more information to the act segmentation model; and 2) Alignment PE is shared across all modalities and fusion layer and its absence causes more harm to sequences with longer lengths, as act segmentation takes longer shot sequences (entire video) compared to scene segmentation (17 shots). Overall, the drop in performance indicates that the proposed Alignment P.E. is an essential component for video segmentation tasks. + +We further remove the proposed Alignment PE from bottleneck fusion tokens and show results in Tab. 4b. We observe a performance drop when removing the Alignment PE. It is worth mentioning that the performance drop is more noticeable when multiple modalities are involved, (e.g. V + T model), which suggests that the information from subtitles requires precise temporal alignment in order to be effective during multimodal fusion. + +Multimodal Fusion Strategies. Tab. 4c compares our proposed fusion tokens with the commonly used late fusion strategy. The results show that the temporal bottleneck fusion clearly outperforms late fusion, demonstrating the effectiveness of aligned bottleneck tokens in improving the performance across both tasks. + +Different Input Modalities. We study the impact of different modalities by removing them from the input and present results on scene segmentation and act segmentation. In scene segmentation (Tab. 4d), we find that the Bassl feature fol + +Table 3: TP identification: comparison with SoTA. MEGA* denotes the MEGA using the same synchronization as [30] for fair comparison. T*,V,T,A denote Textual-screenplay, Visual, Textual-subtitle and Acoustic features, respectively. + +
caseScene Seg.Act Segmentation
AP↑TA↑PA↑D↓
w/o align. PE57.775.297.3731.04
w. align. PE58.5913.9320.729.19
+ +(a) Effectiveness of Alignment Positional Encoding. + +
casemodalityScene Seg.Act Segmentation
AP↑TA↑PA↑D↓
w/o align.PEV58.3113.6020.539.47
w. align.PEV58.5913.9320.729.19
w/o align.PEV + T-13.0120.139.56
w. align.PEV + T-14.6321.788.96
+ +(b) Effectiveness of Normalized Positional Encoding in bottleneck tokens. + +
MM. integ. typeScene Seg.Act Segmentation
AP↑TA↑PA↑D↓
LateFusion58.2412.5719.2110.00
Bottleneck58.5913.9320.729.19
+ +(c) Multi-modal fusion strategies. + +
changeAP↑
-clip58.09
-place57.51
-bassl51.88
-clip-place57.92
-58.59
+ +(d) Impact from input modalities on scene seg. + +
changeTA↑PA↑D↓
-clip6.0910.6621.81
-place13.5719.879.22
-action13.3120.2010.38
-appr13.4220.598.85
-13.9320.729.19
+subtitle14.6321.788.96
+ +(e) Impact from input modalities on act segmentation. + +
synopsis synch. byM for synch.TA↑PA↑D↓
[30]T*10.5114.548.98
MEGAV13.9320.729.19
MEGAV + T14.6321.788.96
+ +(f) Impact of Synchronization with multimodal video features on act segmentation. + +
ApproachFeature Set Pretrained onAP↑Params↓SPS↑
BaSSL [27]Movienet57.415.77M6244.99
LGSS [35]M+P+I52.9366.16M206.36
MEGAM+P+I58.5967.57M1736.13
+ +(g) Impact from feature set and model size on scene seg. SPS denotes # of samples per second. + +
ApproachFeature SetTA↑PA↑D↓Params↓SPS↑
GRAPHTP [32]Set1 [32]9.1212.639.770.745M25.40
GRAPHTP [32]Set24.727.379.696.78M14.36
MEGASet214.1922.109.686.78M18.24
+ +(h) Impact from feature set and model size on act seg. Set1 includes Visual (appr), Audio (YAMNet), Textual (script-USE). Set2 has Visual (appr,clip,action.place), Audio (audio), Textual (text from subtitle). + +Table 4: Ablation studies on MEGA components. + +lowed by place are the most important. This is because the BaSSL [27] model is pretrained for scene segmenta- + +tion and place consistency is critical for scene segmentation. In act segmentation (Tab. 4e), we find that the CLIP feature pre-trained on IMDB, followed by subtitle are the most important features. This is because the clip model is pre-trained on abstract concepts (e.g. genre, micro genre, character type and coarse key places), thus the CLIP feature contains richer semantics, and subtitle provides complementary rich semantic information. These high level semantics are considered useful for act segmentation. Overall, when all the features are included, the model is able to leverage the unique information provided by each feature and yields the best performance. + +Cross-modality Synchronization. Tab. 4f studies the effectiveness of the proposed cross modality synchronization on act segmentation. To establish a baseline, we use the probability scores provided by [32] and derived by aligning synopsis sentences to scenes using screenplay [30] (T* in Tab. 4f denotes screenplay). For a fair comparison, we repeat the scores provided for each scene on all of its shots and then re-normalize2. MEGA with visual only input outperforms [30] across two metrics (PA and TA) and when we add the subtitle features (T in Tab. 4f denotes subtitle), MEGA outperforms [30] across all the metrics. The results demonstrate that the proposed cross-domain synchronization works effectively and generalize well to various modalities. It is worth mentioning that the proposed method generates act segmentation without requiring the screenplay, which makes it practical for various industrial applications. + +Impact of Feature Set. In Tab. 4g, we examine whether feature set plays an outsized role in MEGA's improved performance over other methods. On the same feature set of $\mathrm{M} + \mathrm{P} + \mathrm{I}$ , we outperform LGSS [35] while only introducing a small number of additional parameters. BaSSL [27] achieves slightly lower performance using only Movienet features, indicating that the use of additional features is not the primary reason for our improved performance. + +Impact of Model Size. We finally look into the impact of model size on the performance. To establish the fair comparison, we first expand GRAPHTP [32] which shares the same input as MEGA to roughly the same number of parameters as MEGA. Our results on act segmentation (Tab. 4h) show that MEGA outperforms the previous SoTA, GRAPHTP [32], which indicates the MEGA has efficient and effective design. + +# 4.5. Fusion with Audio Modality + +We also experimented with the effect of adding audio. Movienet [18] has released Short Time Fourier Transform (STFT) features extracted from audio files. We use the same audio backbone as [35]. However, by adding audio features + +
ApproachModalityAP↑ [%]
LGSS [35]V(place)39.00
ShotCoL [8];V46.77
SCRL [45]V54.55
MEGAV(place,clip,bassl)58.59
LGSS [35]V(place)+A43.4
ShotCoL [8];V+A44.32
SCRL [45]V+A50.80
MEGAV(place,clip,bassl)+A55.36
+ +Table 5: Scene Seg. with audio. $\ddagger$ denotes copying from [45]. + +in MEGA, we see a drop in the performance (see Tab. 5). Although [8, 35] have shown improvements across multiple models by adding the audio modality across Movienet-150 dataset [35] (where the split is not publicly available) or a private dataset: AdCuepoints [8], Wu et al. [45] have observed a similar trend as our experiments, where adding the released audio features in Movienet [18] to SCRL [45] and ShotCoL [8] drops the performance (see Tab. 5). Possible reasons can be 1) the audio features published by Movienet via STFT $^3$ are an incomplete view of the shot from audio modality either in representation or in terms of the audio chunk from each shot they used, and the raw audio files are not available. 2) our multimodal fusion strategy cannot exploit the possible complementary information or filter the harmful or confusing signals from the audio modality. + +# 5. Discussion and Conclusion + +Limitations. The explorations in this work are limited to appearance, location, activity, acoustic and textual features. For long movie segmentation, however, providing the name of actors (tabular data) and having a specific component for actor identification in the movie can help both the synchronization and the act/scene segmentation models. We will explore the use of this data. + +The results demonstrated that richer semantic representations from the clip features enhanced the performance for long video segmentation. To obtain better performing representations for long video understanding one can use large amount of unlabeled data with carefully selected pretext tasks for understanding long context. We will investigate the use of SSL to train a rich multimodal representation from videos and will examine the learned representations across multiple long video understanding tasks. + +Conclusion. This paper introduces MEGA, a unified solution for long video segmentation. Our design of normalized positional encoding, and their integration into fusion tokens allows MEGA to learn consistent patterns from inputs with variable lengths and efficiently and effectively align and fuse them across different modalities. Our synchronization schema further allows the use of rich multimodal tokens to + +be used in transferring the labels from synopsis sentences to movie shots, facilitating the knowledge distillation from synopses to movies. MEGA achieves state-of-the-art performance compared with previous works. + +# References + +[1] Sentence-transformers model: all-minilm-l6-v2 from Hugging Face. https://huggingface.co/sentence-transformers/all-MiniLM-L6-v2.3 +[2] Yuki Asano, Mandela Patrick, Christian Rupprecht, and Andrea Vedaldi. Labelling unlabelled videos from scratch with multi-modal self-supervision. Advances in Neural Information Processing Systems, 33:4660-4671, 2020. 2 +[3] Yusuf Aytar, Carl Vondrick, and Antonio Torralba. Soundnet: Learning sound representations from unlabeled video. Advances in neural information processing systems, 29, 2016. 2 +[4] Lorenzo Baraldi, Costantino Grana, and Rita Cucchiara. A deep siamese network for scene detection in broadcast videos. In Proceedings of the 23rd ACM international conference on Multimedia, pages 1199-1202, 2015. 6 +[5] Jessica Brody. Save the Cat! Writes a Novel: The Last Book On Novel Writing You'll Ever Need. Ten Speed Press, 2018. 2, 3 +[6] Joao Carreira and Andrew Zisserman. Quo vadis, action recognition? a new model and the kinetics dataset. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 6299-6308, 2017. 3 +[7] Vasileios T Chasanis, Aristidis C Likas, and Nikolaos P Galatsanos. Scene detection in videos using shot clustering and sequence alignment. IEEE transactions on multimedia, 11(1):89-100, 2008. 6 +[8] Shixing Chen, Xiaohan Nie, David Fan, Dongqing Zhang, Visual Bhat, and Raffay Hamid. Shot contrastive self-supervised learning for scene boundary detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9796-9805, 2021. 1, 2, 4, 6, 8 +[9] Zi-Yi Dou, Yichong Xu, Zhe Gan, Jianfeng Wang, Shuohang Wang, Lijuan Wang, Chenguang Zhu, Pengchuan Zhang, Lu Yuan, Nanyun Peng, et al. An empirical study of training end-to-end vision-and-language transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18166-18176, 2022. 1, 2, 3, 4 +[10] Philip Gorinski and Mirella Lapata. Movie script summarization as graph-based scene extraction. In Proceedings of the 2015 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pages 1066-1076, 2015. 7 +[11] Chunhui Gu, Chen Sun, David A Ross, Carl Vondrick, Caroline Pantofaru, Yeqing Li, Sudheendra Vijayanarasimhan, George Toderici, Susanna Ricco, Rahul Sukthankar, et al. Ava: A video dataset of spatio-temporally localized atomic visual actions. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 6047-6056, 2018. 6 +[12] Saurabh Gupta, Judy Hoffman, and Jitendra Malik. Cross modal distillation for supervision transfer. In Proceedings of + +the IEEE conference on computer vision and pattern recognition, pages 2827-2836, 2016. 2 +[13] Bo Han and Weiguo Wu. Video scene segmentation using a novel boundary evaluation criterion and dynamic programming. In 2011 IEEE International conference on multimedia and expo, pages 1-6. IEEE, 2011. 6 +[14] Michael Hauge. Storytelling Made Easy: Persuade and Transform Your Audiences, Buyers, And Clients-Simply, Quickly, and Profitably. BookBaby, 2017. 1, 2, 3, 7 +[15] Lisa Anne Hendricks, John Mellor, Rosalia Schneider, Jean-Baptiste Alayrac, and Aida Nematzadeh. Decoupling the role of data, attention, and losses in multimodal transformers. Transactions of the Association for Computational Linguistics, 9:570-585, 2021. 2 +[16] Dan Hendrycks and Kevin Gimpel. Gaussian error linear units (gelus). arXiv preprint arXiv:1606.08415, 2016. 6 +[17] Qingqiu Huang, Yu Xiong, and Dahua Lin. Unifying identification and context learning for person recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 2217-2225, 2018. 6 +[18] Qingqiu Huang, Yu Xiong, Anyi Rao, Jiaze Wang, and Dahua Lin. Movienet: A holistic dataset for movie understanding. In European Conference on Computer Vision, pages 709-727. Springer, 2020. 2, 5, 6, 8 +[19] Andrew Jaegle, Felix Gimeno, Andy Brock, Oriol Vinyals, Andrew Zisserman, and Joao Carreira. Perceiver: General perception with iterative attention. In International conference on machine learning, pages 4651-4664. PMLR, 2021. 2 +[20] Prannay Khosla, Piotr Teterwak, Chen Wang, Aaron Sarna, Yonglong Tian, Phillip Isola, Aaron Maschinot, Ce Liu, and Dilip Krishnan. Supervised contrastive learning. Advances in Neural Information Processing Systems, 33:18661-18673, 2020. 5 +[21] Wonjae Kim, Bokyung Son, and Ildoo Kim. Vilt: Vision-and-language transformer without convolution or region supervision. In International Conference on Machine Learning, pages 5583-5594. PMLR, 2021. 1, 2, 4 +[22] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. 6 +[23] Qiuqiang Kong, Yin Cao, Turab Iqbal, Yuxuan Wang, Wenwu Wang, and Mark D Plumbley. Panns: Large-scale pretrained audio neural networks for audio pattern recognition. IEEE/ACM Transactions on Audio, Speech, and Language Processing, 28:2880-2894, 2020. 3 +[24] Shengjie Luo, Shanda Li, Tianle Cai, Di He, Dinglan Peng, Shuxin Zheng, Guolin Ke, Liwei Wang, and Tie-Yan Liu. Stable, fast and accurate: Kernelized attention with relative positional encoding. Advances in Neural Information Processing Systems, 34:22795-22807, 2021. 2 +[25] Rada Mihalcea and Paul Tarau. Textrank: Bringing order into text. In Proceedings of the 2004 conference on empirical methods in natural language processing, pages 404-411, 2004. 7 +[26] Paramita Mirza, Mostafa Abouhamra, and Gerhard Weikum. Alignnarr: Aligning narratives on movies. In The 59th Annual + +Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing, pages 427-433. ACL, 2021. 3, 5 +[27] Jonghwan Mun, Minchul Shin, Gunsoo Han, Sangho Lee, Seongsu Ha, Joonseok Lee, and Eun-Sol Kim. Boundary-aware self-supervised learning for video scene segmentation. arXiv preprint arXiv:2201.05277, 2022. 2, 3, 4, 6, 7, 8 +[28] Arsha Nagrani, Shan Yang, Anurag Arnab, Aren Jansen, Cordelia Schmid, and Chen Sun. Attention bottlenecks for multimodal fusion. Advances in Neural Information Processing Systems, 34:14200-14213, 2021. 2, 3, 4 +[29] Pinelopi Papalampidi, Frank Keller, Lea Frermann, and Mirella Lapata. Screenplay summarization using latent narrative structure. In Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics, pages 1920-1933, 2020. 6, 7 +[30] Pinelopi Papalampidi, Frank Keller, and Mirella Lapata. Movie plot analysis via turning point identification. arXiv preprint arXiv:1908.10328, 2019. 1, 2, 3, 6, 7, 8 +[31] Pinelopi Papalampidi, Frank Keller, and Mirella Lapata. Film trailer generation via task decomposition. arXiv preprint arXiv:2111.08774, 2021. 2, 5 +[32] Pinelopi Papalampidi, Frank Keller, and Mirella Lapata. Movie summarization via sparse graph construction. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 13631-13639, 2021. 1, 2, 4, 5, 6, 7, 8 +[33] Patrice Pavis. Dictionary of the theatre: Terms, concepts, and analysis. University of Toronto Press, 1998. 2 +[34] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning, pages 8748-8763. PMLR, 2021. 3, 5 +[35] Anyi Rao, Linning Xu, Yu Xiong, Guodong Xu, Qingqiu Huang, Bolei Zhou, and Dahua Lin. A local-to-global approach to multi-modal movie scene segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10146-10155, 2020. 1, 2, 5, 6, 7, 8 +[36] Zeeshan Rasheed and Mubarak Shah. Detection and representation of scenes in videos. IEEE transactions on Multimedia, 7(6):1097-1105, 2005. 6 +[37] Daniel Rotman, Dror Porat, and Gal Ashour. Optimal sequential grouping for robust video scene detection using multiple modalities. International Journal of Semantic Computing, 11(02):193-208, 2017. 6 +[38] Peter Shaw, Jakob Uszkoreit, and Ashish Vaswani. Self-attention with relative position representations. In Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 2 (Short Papers), pages 464–468, 2018. 2 +[39] Tomáš Souček and Jakub Lokoc. Transnet v2: an effective deep network architecture for fast shot transition detection. arXiv preprint arXiv:2008.04838, 2020. 1, 3 + +[40] Jianlin Su, Yu Lu, Shengfeng Pan, Bo Wen, and Yunfeng Liu. Roformer: Enhanced transformer with rotary position embedding. arXiv preprint arXiv:2104.09864, 2021. 2 +[41] Makarand Tapaswi, Martin Bauml, and Rainer Stiefelhagen. Storygraphs: visualizing character interactions as a timeline. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 827-834, 2014. 6 +[42] Makarand Tapaswi, Martin Bäuml, and Rainer Stiefelhagen. Aligning plot synopses to videos for story-based retrieval. International Journal of Multimedia Information Retrieval, 4(1):3-16, 2015. 3 +[43] Makarand Tapaswi, Martin Bauml, and Rainer Stiefelhagen. Book2movie: Aligning video scenes with book chapters. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1827-1835, 2015. 3 +[44] Yikai Wang, Wenbing Huang, Fuchun Sun, Tingyang Xu, Yu Rong, and Junzhou Huang. Deep multimodal fusion by channel exchanging. Advances in Neural Information Processing Systems, 33:4835-4845, 2020. 2, 3 +[45] Haoqian Wu, Keyu Chen, Yanan Luo, Ruizhi Qiao, Bo Ren, Haozhe Liu, Weicheng Xie, and Linlin Shen. Scene consistency representation learning for video scene segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14021-14030, 2022. 2, 4, 5, 6, 8 +[46] Saining Xie, Ross Girshick, Piotr Dólar, Zhuowen Tu, and Kaiming He. Aggregated residual transformations for deep neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1492-1500, 2017. 3 +[47] Yu Xiong, Qingquiu Huang, Lingfeng Guo, Hang Zhou, Bolei Zhou, and Dahua Lin. A graph-based framework to bridge movies and synopses. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4592-4601, 2019. 3 +[48] Ning Zhang, Manohar Paluri, Yaniv Taigman, Rob Fergus, and Lubomir Bourdev. Beyond frontal faces: Improving person recognition using multiple cues. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4804-4813, 2015. 6 +[49] Chao Zhao, Wenlin Yao, Dian Yu, Kaiqiang Song, Dong Yu, and Jianshu Chen. Learning-by-narrating: Narrative pretraining for zero-shot dialogue comprehension. In Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers), pages 212-218, Dublin, Ireland, May 2022. Association for Computational Linguistics. 3 +[50] Bolei Zhou, Agata Lapedriza, Aditya Khosla, Aude Oliva, and Antonio Torralba. Places: A 10 million image database for scene recognition. IEEE transactions on pattern analysis and machine intelligence, 40(6):1452-1464, 2017. 3, 6 \ No newline at end of file diff --git a/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/images.zip b/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..d9b0b6f6310496c8de00abbdce82feb084997b08 --- /dev/null +++ b/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:f77065b3bef225ef8ca82c3d120963020a290413a766b01607b7efb82a499e6b +size 457057 diff --git a/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/layout.json b/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..b178f5647ecf5bb29fabf1772b9072aae4e21a30 --- /dev/null +++ b/2023/MEGA_ Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation/layout.json @@ -0,0 +1,8763 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 110, + 103, + 483, + 138 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 103, + 483, + 138 + ], + "spans": [ + { + "bbox": [ + 110, + 103, + 483, + 138 + ], + "type": "text", + "content": "MEGA: Multimodal Alignment Aggregation and Distillation For Cinematic Video Segmentation" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 116, + 160, + 475, + 202 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 116, + 160, + 475, + 202 + ], + "spans": [ + { + "bbox": [ + 116, + 160, + 475, + 202 + ], + "type": "text", + "content": "Najmeh Sadoughi1, Xinyu Li1, Avijit Vajpayee1, David Fan1, Bing Shuai2, Hector Santos-Villalobos1, Vimal Bhat1, Rohith MV1 \n1Amazon Prime Video, 2AWS AI Labs" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 99, + 205, + 493, + 217 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 99, + 205, + 493, + 217 + ], + "spans": [ + { + "bbox": [ + 99, + 205, + 493, + 217 + ], + "type": "text", + "content": "{nnnourab,xxnl,avivaj,fandavi,bshuai,hsantosv,vimalb,kurohith}@amazon.com" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 244, + 192, + 258 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 244, + 192, + 258 + ], + "spans": [ + { + "bbox": [ + 143, + 244, + 192, + 258 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 271, + 290, + 522 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 271, + 290, + 522 + ], + "spans": [ + { + "bbox": [ + 46, + 271, + 290, + 522 + ], + "type": "text", + "content": "Previous research has studied the task of segmenting cinematic videos into scenes and into narrative acts. However, these studies have overlooked the essential task of multimodal alignment and fusion for effectively and efficiently processing long-form videos (" + }, + { + "bbox": [ + 46, + 271, + 290, + 522 + ], + "type": "inline_equation", + "content": ">60\\mathrm{min}" + }, + { + "bbox": [ + 46, + 271, + 290, + 522 + ], + "type": "text", + "content": "). In this paper, we introduce Multimodal alignmEnt aGgregation and distillAtion (MEGA) for cinematic long-video segmentation. MEGA tackles the challenge by leveraging multiple media modalities. The method coarsely aligns inputs of variable lengths and different modalities with alignment positional encoding. To maintain temporal synchronization while reducing computation, we further introduce an enhanced bottleneck fusion layer which uses temporal alignment. Additionally, MEGA employs a novel contrastive loss to synchronize and transfer labels across modalities, enabling act segmentation from labeled synopsis sentences on video shots. Our experimental results show that MEGA outperforms state-of-the-art methods on MovieNet dataset for scene segmentation (with an Average Precision improvement of " + }, + { + "bbox": [ + 46, + 271, + 290, + 522 + ], + "type": "inline_equation", + "content": "+1.19\\%" + }, + { + "bbox": [ + 46, + 271, + 290, + 522 + ], + "type": "text", + "content": ") and on TRI-POD dataset for act segmentation (with a Total Agreement improvement of " + }, + { + "bbox": [ + 46, + 271, + 290, + 522 + ], + "type": "inline_equation", + "content": "+5.51\\%" + }, + { + "bbox": [ + 46, + 271, + 290, + 522 + ], + "type": "text", + "content": ")." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 548, + 127, + 561 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 548, + 127, + 561 + ], + "spans": [ + { + "bbox": [ + 47, + 548, + 127, + 561 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 570, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 288, + 713 + ], + "type": "text", + "content": "In the world of video production, movies are composed of smaller units called shots, scenes, and acts. Shots are a continuous set of frames, a scene is a sequence of shots that tell a story, and an act is a thematic section of a narrative [14]. While computer vision has made significant strides in shot detection [39], scene and act segmentation remain a challenge, despite their potential for smart video navigation, advertisement insertion, and movie summarization. Cinematic content comprises of different data sources, including audio, visual, and text data, as well as derivative data sources from the narrative, including location, appearance, tone, or acoustic events. In this work, we will refer to all of these" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 318, + 246, + 539, + 398 + ], + "blocks": [ + { + "bbox": [ + 318, + 246, + 539, + 398 + ], + "lines": [ + { + "bbox": [ + 318, + 246, + 539, + 398 + ], + "spans": [ + { + "bbox": [ + 318, + 246, + 539, + 398 + ], + "type": "image", + "image_path": "0006a7d310399a74f432bb3da97e518fc571bd114cbb9fb6c04e4fff1ad472ba.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 407, + 547, + 456 + ], + "lines": [ + { + "bbox": [ + 305, + 407, + 547, + 456 + ], + "spans": [ + { + "bbox": [ + 305, + 407, + 547, + 456 + ], + "type": "text", + "content": "Figure 1: MEGA works well on both scene segmentation and act segmentation tasks, outperforming previous work with significant margin. V,T*,T,A denotes video, screenplay, subtitle and audio respectively." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 470, + 547, + 506 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 470, + 547, + 506 + ], + "spans": [ + { + "bbox": [ + 304, + 470, + 547, + 506 + ], + "type": "text", + "content": "input components as \"modalities\" of cinematic content. Previous work has not fully explored how to align and aggregate these modalities which have different granularities." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 510, + 548, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 510, + 548, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 548, + 715 + ], + "type": "text", + "content": "We propose to address scene and act segmentation tasks with an unified multimodal Transformer. However, this approach presents two main challenges. Firstly, there is the issue of cross modality information synchronization and fusion at the shot level. Previous studies which use multimodal fusion for scene and act segmentation perform early [8, 32] or late fusion of features [35], and have not explored fusion strategies which utilize multimodal temporal alignment. Additionally, the fusion strategies that utilize temporal alignment such as merged attention or cross modality attention [9, 21] are computationally expensive and not generalizable to a large number of modalities. Secondly, due to the challenges associated with labeling a long video on act segmentation, the labels for act segmentation are provided on synopsis sentences [30] which do not provide timestamps. To avoid the more challenging task of cross-modal synchronization, previous studies on act segmentation [30, 32] rely" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23331" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 288, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 288, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 288, + 120 + ], + "type": "text", + "content": "on textual screenplay to transfer the labels from synopsis to movie, ignoring the rich multimodal information from the video, and introducing an additional dependency on screenplay data which is not always available." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 120, + 290, + 347 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 120, + 290, + 347 + ], + "spans": [ + { + "bbox": [ + 46, + 120, + 290, + 347 + ], + "type": "text", + "content": "To address these challenges, we introduce Multimodal alignmEnt aGgregation and distillation (MEGA). MEGA includes a novel module called alignment positional encoding which aligns inputs of variable lengths and different modalities at a coarse temporal level. To fuse the aligned embeddings of different modalities in an efficient and effective manner, we adopt the bottleneck fusion tokens [28] and append a set of fusion tokens to each modality. These tokens share the same sequence length as the normalized positional encoding for different modalities, allowing us to inject them with the coarse temporal information, enabling information fusion in a better aligned embedding space. To address the issue of cross-domain knowledge transfer, we introduce a cross-modal synchronization approach. This method allows us to transfer the manually labeled act boundaries from synopsis level to movie level using rich multimodal information, enabling us to train MEGA directly on videos without relying on screenplay – which was a hard requirement for previous works [30, 32]." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 348, + 288, + 443 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 348, + 288, + 443 + ], + "spans": [ + { + "bbox": [ + 46, + 348, + 288, + 443 + ], + "type": "text", + "content": "We test our proposed alignment and aggregation modules on the Movienet-318 [18] and the TRIPOD datasets [30], and we test our cross modality synchronization module on TRIPOD alone, as the labels are provided on a different modality during training. Our proposed MEGA outperforms previous SoTA on scene segmentation on the Movienet-318 dataset (by " + }, + { + "bbox": [ + 46, + 348, + 288, + 443 + ], + "type": "inline_equation", + "content": "+1.19\\%" + }, + { + "bbox": [ + 46, + 348, + 288, + 443 + ], + "type": "text", + "content": " in AP) and on act segmentation on the TRIPOD dataset (by " + }, + { + "bbox": [ + 46, + 348, + 288, + 443 + ], + "type": "inline_equation", + "content": "+5.51\\%" + }, + { + "bbox": [ + 46, + 348, + 288, + 443 + ], + "type": "text", + "content": " in TA). Our contributions are:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 55, + 449, + 287, + 554 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 55, + 449, + 286, + 483 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 449, + 286, + 483 + ], + "spans": [ + { + "bbox": [ + 55, + 449, + 286, + 483 + ], + "type": "text", + "content": "1. Alignment positional encoding module and a fusion bottleneck layer that performs multimodal fusion with aligned multi-modality inputs." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 55, + 484, + 287, + 518 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 484, + 287, + 518 + ], + "spans": [ + { + "bbox": [ + 55, + 484, + 287, + 518 + ], + "type": "text", + "content": "2. A cross-domain knowledge transfer module that synchronizes features across-domain, and enables knowledge distillation without requiring extra information." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 55, + 520, + 286, + 554 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 520, + 286, + 554 + ], + "spans": [ + { + "bbox": [ + 55, + 520, + 286, + 554 + ], + "type": "text", + "content": "3. SoTA performance on scene and act segmentation tasks, with detailed ablations, which can be used as reference for future work." + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 47, + 562, + 134, + 574 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 562, + 134, + 574 + ], + "spans": [ + { + "bbox": [ + 47, + 562, + 134, + 574 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "type": "text", + "content": "Scene Segmentation in Cinematic Content: Recent works on scene segmentation have explored self-supervised learning (SSL) [8,27,45]. Self-supervised pretext tasks have included maximizing the similarity between nearby shots compared to randomly selected ones [8], maximizing the similarity between pairs of images selected according to scene consistency [45], and maximizing the similarity between pairs of images selected according to pseudo scene boundaries [27]. While several previous works have used multimodal inputs for this task [8,35,45], they have either utilized late fusion of features with predefined weights for each" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 72, + 545, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 120 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 120 + ], + "type": "text", + "content": "modality [35] or have utilized early integration of features derived via SSL [8, 45]. In this paper, we explore how to better align and integrate features from different modalities for scene segmentation." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 121, + 547, + 348 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 121, + 547, + 348 + ], + "spans": [ + { + "bbox": [ + 304, + 121, + 547, + 348 + ], + "type": "text", + "content": "Act Segmentation in Cinematic Content: Movie screenplays follow a general narrative structure on how a plot unfolds across the story. Several theories have been proposed in this domain dating as far back as Aristotle, who defined a 3 act structure with a beginning (protasis), middle (epitasis), and end (catastrophe) [33]. Modern screenplays are usually written with a 6 act structure [14], named as \"the setup\", \"the new situation\", \"progress\", \"complications and higher stakes\", \"the final push\", and \"the aftermath\", separated by five turning points (TPs). Prior approaches in narrative segmentation on movies have adopted the aforementioned 6 act structure and posed the problem as identifying the 5 TPs that separate these 6 acts. [32] is to our knowledge the only prior work that utilizes visual domain in act segmentation by using a pre-trained teacher model trained on textual input to train a student Graph Convolutional network with audio-visual-text representations as input. In contrast, our work uses a new multimodal fusion and distillation applied on the modalities which are available with the movie." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 351, + 547, + 518 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 351, + 547, + 518 + ], + "spans": [ + { + "bbox": [ + 304, + 351, + 547, + 518 + ], + "type": "text", + "content": "Multimodal Aggregation: Previous SoTAs on multimodal fusion with transformers perform early fusion of the features as inputs to the transformer [19], merge attention between them requiring more memory [9,21], use cross attention between two modalities [9,44], or add cross-modal interactions more efficiently via bottleneck tokens or exchanging some of their latents [15, 28]. [28] provides information flow between modalities efficiently by utilizing bottleneck tokens to tame the quadratic complexity of pairwise attention. This global exchange between modalities may not be enough for long videos, which require an adaptive fusion in different temporal locations. Our model considers [28] as baseline and extends it to incorporate local information during information exchange between modalities." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 520, + 547, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 520, + 547, + 628 + ], + "spans": [ + { + "bbox": [ + 304, + 520, + 547, + 628 + ], + "type": "text", + "content": "Positional Encoding: Previous studies on improving the positional encoding in long sequence modeling have mostly focused on adding relative distance positional encoding [24, 38, 40]. However, they do not offer solutions on better maintaining the relative position of latent tokens with respect to their starting point in time in long sequences with variable lengths, which is important for long movie narrative understanding [5, 14]. We propose Alignment Positional Encoding to bridge this gap." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 630, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 547, + 713 + ], + "type": "text", + "content": "Cross-Modality Synchronization & Distillation: To transfer the labels from synopsis to movie shots, we use cross-modality distillation. Previous cross-modality distillation studies for label transfer across modalities are focused on parallel data with the same granularity [2,3,12], or where the alignment is known [31]. Alignment of features at different granularities in the same modality, such as screenplay" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "text", + "content": "23332" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 178 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 178 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 178 + ], + "type": "text", + "content": "scenes to synopsis sentences [26, 49] and across modalities such as aligning synopsis sentences to visual shots [42, 47], book chapters to visual scenes [43] have been previously explored. While majority of these works rely on unsupervised optimization techniques [26, 42, 43, 49], there are studies that use supervised labels to improve the representations used for optimization [47]. We present an alignment approach with self-supervised loss for synchronizing data in different modalities of cinematic content to enable distillation." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 191, + 129, + 205 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 191, + 129, + 205 + ], + "spans": [ + { + "bbox": [ + 47, + 191, + 129, + 205 + ], + "type": "text", + "content": "3. Methodology" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 212, + 289, + 462 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 212, + 289, + 462 + ], + "spans": [ + { + "bbox": [ + 46, + 212, + 289, + 462 + ], + "type": "text", + "content": "MEGA processes long videos and performs video segmentation in three major steps (Fig. 2). First, a video " + }, + { + "bbox": [ + 46, + 212, + 289, + 462 + ], + "type": "inline_equation", + "content": "V" + }, + { + "bbox": [ + 46, + 212, + 289, + 462 + ], + "type": "text", + "content": " is chunked into shots, and multiple features such as scene related features and sound event features are extracted at the shot-level (Sec. 3.1). The system is built on shot-level representation for two reasons: (1) scene and act boundaries always align with shot boundaries, and (2) the content within a shot remains similar, which allows efficient yet meaningful sampling without losing important information. Second, the embeddings from different input samples and each modality are coarsely aligned with a proposed alignment embedding (Sec. 3.2), and the alignment positional tokens are used to refine the commonly used bottleneck fusion tokens for cross-modal feature fusion (Sec. 3.2). Third, a linear layer is applied on top of the fused representations to generate scene and act boundaries (Sec. 3.3). Finally, to address the challenge of cross-domain knowledge transfer where labels from one domain may not directly align with another domain (e.g. act labels on synopsis sentences do not have movie-level timing information), we propose a cross-modal synchronization module that is simple yet effective (Sec. 3.4)." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 471, + 135, + 483 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 471, + 135, + 483 + ], + "spans": [ + { + "bbox": [ + 47, + 471, + 135, + 483 + ], + "type": "text", + "content": "3.1. Preprocessing" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 489, + 288, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 489, + 288, + 677 + ], + "spans": [ + { + "bbox": [ + 46, + 489, + 288, + 677 + ], + "type": "text", + "content": "We chose to utilize Transnet-v2 [39] for shot segmentation due to its superior performance and efficiency. We list our selection of pre-trained models and associated parameters in Tab. 1. As each pretrained feature extraction model has different requirements for input resolution and sampling rate, we first sample the input at various sample rates (as shown in Table 1). It is worth noting that the " + }, + { + "bbox": [ + 46, + 489, + 288, + 677 + ], + "type": "inline_equation", + "content": "\\mathrm{CLIP}_{\\mathrm{movie}}" + }, + { + "bbox": [ + 46, + 489, + 288, + 677 + ], + "type": "text", + "content": " model is the CLIP [34] model with ViT-B/32 backbone fine-tuned on paired IMDB-image/text dataset. IMDB-image dataset comprises 1.6M images from 31.3K unique movies/TV series with 761 unique textual labels. The features attributed to each shot are the ones with overlap with the shot time stamp (More details are in Appendix). After feature extraction, we aggregate the features for each shot and normalize the feature dimension with linear projection as:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 110, + 678, + 287, + 716 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 678, + 287, + 716 + ], + "spans": [ + { + "bbox": [ + 110, + 678, + 287, + 716 + ], + "type": "interline_equation", + "content": "E _ {i} ^ {m} = g ^ {m} \\left(\\frac {1}{T _ {i} ^ {m}} \\sum_ {j = 1} ^ {T _ {i} ^ {m}} S _ {i j} ^ {m}\\right) \\tag {1}", + "image_path": "d99f3e93a4c793f446dcdb3a03fe763b8ea803ea6a4f34497fac2f63adb0cc40.jpg" + } + ] + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 310, + 70, + 543, + 171 + ], + "blocks": [ + { + "bbox": [ + 310, + 70, + 543, + 171 + ], + "lines": [ + { + "bbox": [ + 310, + 70, + 543, + 171 + ], + "spans": [ + { + "bbox": [ + 310, + 70, + 543, + 171 + ], + "type": "table", + "html": "
Feature extractorInput Freq.Input Res.Feature dim.
Visual input
BASSL [27] (bassi)Varying22422048
ResNetPlace [50] (place)1Hz22422048
ResNeXt101 [46] (appr)1Hz22422048
I3D [6] (action)16Hz16 × 22422048
CLIPmovie (clip)1Hz2242768
Acoustic input
PANNs [23] (audio)1Hz10 × 32K2048
Linguistic input
all-MiniLM-L6-v2 [1] (text)Varying-384
", + "image_path": "d9f17889695c9ae8dd57891586ec7033d56b223e3bed26ab329ea793531c0cc7.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 180, + 545, + 204 + ], + "lines": [ + { + "bbox": [ + 305, + 180, + 545, + 204 + ], + "spans": [ + { + "bbox": [ + 305, + 180, + 545, + 204 + ], + "type": "text", + "content": "Table 1: Sampling strategy and feature extraction backbones used for different modalities." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "spans": [ + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "inline_equation", + "content": "E_{i}^{m}\\in \\mathbb{R}^{C}" + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "text", + "content": " denotes the embedding from the " + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "text", + "content": "-th shot of " + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "text", + "content": "-th modality, " + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "inline_equation", + "content": "S_{ij}^{m}\\in \\mathbb{R}^{D^{m}}" + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "text", + "content": " is the " + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "text", + "content": "-th sampled feature of " + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "text", + "content": "-th modality from " + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "text", + "content": "-th shot, and " + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "inline_equation", + "content": "g^{m}" + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "text", + "content": " is a linear projection layer that projects feature dimension for " + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "text", + "content": "-th modality to a common dimension " + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 304, + 212, + 547, + 271 + ], + "type": "text", + "content": " across all modalities." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 272, + 547, + 331 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 272, + 547, + 331 + ], + "spans": [ + { + "bbox": [ + 304, + 272, + 547, + 331 + ], + "type": "text", + "content": "While it is possible to create an end-to-end system starting from raw shot inputs and training the model from scratch, pre-extracting the features from pretrained models is generally more scalable and efficient in actual industrial scenarios, hence we rely on the latter." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 340, + 507, + 353 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 340, + 507, + 353 + ], + "spans": [ + { + "bbox": [ + 306, + 340, + 507, + 353 + ], + "type": "text", + "content": "3.2. Cross-modality Alignment and Fusion" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "spans": [ + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "text", + "content": "For long video segmentation into scenes and acts it is important to model short and long term context and perform effective multimodal fusion. However, the commonly used learnable positional embedding only provides fine-grained granularity and is not suitable for high-level semantic alignment across modalities. Furthermore, for tasks such as act segmentation we expect consistent patterns at normalized position of temporal inputs as the theory suggests approximate locations for each turning point (i.e., " + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "inline_equation", + "content": "25\\%" + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "inline_equation", + "content": "95\\%" + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "text", + "content": " [5, 14, 30]). Hence, in addition to using the traditional positional encoding, we introduce Alignment Positional Encoding layer " + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "inline_equation", + "content": "\\in \\mathbb{R}^{L_n\\times C}" + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "text", + "content": ", which is a learnable embedding layer, for which the index at " + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 359, + 547, + 526 + ], + "type": "text", + "content": "-th temporal unit (e.g., shot) is derived by:" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 378, + 526, + 545, + 553 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 378, + 526, + 545, + 553 + ], + "spans": [ + { + "bbox": [ + 378, + 526, + 545, + 553 + ], + "type": "interline_equation", + "content": "i _ {\\text {a l i g n}} = \\operatorname {f l o o r} \\left(\\frac {L _ {n}}{L} i\\right) \\tag {2}", + "image_path": "77a66e2281e133f1419d49fe0447b9baa6eb951317ccc52817b41faad6caa509.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 558, + 547, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 547, + 676 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 547, + 676 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 558, + 547, + 676 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 304, + 558, + 547, + 676 + ], + "type": "text", + "content": " is the temporal dimension (e.g., number of shots) and " + }, + { + "bbox": [ + 304, + 558, + 547, + 676 + ], + "type": "inline_equation", + "content": "L_{n}" + }, + { + "bbox": [ + 304, + 558, + 547, + 676 + ], + "type": "text", + "content": " is the length of alignment positional encoding which is a hyper-parameter " + }, + { + "bbox": [ + 304, + 558, + 547, + 676 + ], + "type": "inline_equation", + "content": "(L_{n} < L)" + }, + { + "bbox": [ + 304, + 558, + 547, + 676 + ], + "type": "text", + "content": ". We add the alignment positional encoding to the features in conjunction with the conventional positional encoding (see Fig 2). This module is shared across different modalities. This module provides extra information to the network that can be helpful in learning from long training samples with varying lengths, and in coarsely aligning inputs from different modalities before information fusion." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 677, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 547, + 713 + ], + "type": "text", + "content": "Inspired by previous works [9, 28, 44], we choose cross-modal feature fusion, which has been shown to be more effective than early or late fusion. To make our approach scale to" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23333" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 67, + 70, + 521, + 210 + ], + "blocks": [ + { + "bbox": [ + 67, + 70, + 521, + 210 + ], + "lines": [ + { + "bbox": [ + 67, + 70, + 521, + 210 + ], + "spans": [ + { + "bbox": [ + 67, + 70, + 521, + 210 + ], + "type": "image", + "image_path": "b4c1fa0eab68f6677ce713b7eeb86c344366a1b3b7e448da08c09fa934e934a8.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 214, + 547, + 265 + ], + "lines": [ + { + "bbox": [ + 46, + 214, + 547, + 265 + ], + "spans": [ + { + "bbox": [ + 46, + 214, + 547, + 265 + ], + "type": "text", + "content": "Figure 2: The pipeline of the proposed method includes 1) Preprocessing: splitting the video into shots, extraction of features from each shot, pooling and normalization 2) Cross modality fusion and alignment: with the help of alignment positional encoding and bottleneck fusion tokens, 3) Scene/Act Segmentation comprising the segmentation heads. For Scene Segmentation, CE loss is used and for Act Segmentation knowledge transfer loss is used (refer to Sec. 3.4 for details)" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 292, + 289, + 411 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 292, + 289, + 411 + ], + "spans": [ + { + "bbox": [ + 46, + 292, + 289, + 411 + ], + "type": "text", + "content": "multiple modalities, we propose an efficient temporal bottleneck fusion based on [28], and follow their mid-fusion strategy, which comprises of an unimodal transformer encoder followed by a multimodal transformer encoder (See Fig. 2). While [28] proposes to use bottleneck tokens for fusing information across different modalities, these tokens learn to integrate the information across modalities in a global manner. We propose to use " + }, + { + "bbox": [ + 46, + 292, + 289, + 411 + ], + "type": "inline_equation", + "content": "L_{n}" + }, + { + "bbox": [ + 46, + 292, + 289, + 411 + ], + "type": "text", + "content": " fusion tokens, and then integrate them with the same Normalized Positional Encoding to align them with features on the coarse temporal scale (Fig. 3)." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 412, + 290, + 509 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 412, + 290, + 509 + ], + "spans": [ + { + "bbox": [ + 46, + 412, + 290, + 509 + ], + "type": "text", + "content": "The transformer layer per modality then takes in an extra set of aligned fusion tokens concatenated with its input (Fig 2), making it much more efficient compared to other methods such as merged attention or pairwise cross-attention with respect to the number of modalities [9, 21]. Finally, the latent tokens per modality from the last fusion layer (i.e., " + }, + { + "bbox": [ + 46, + 412, + 290, + 509 + ], + "type": "inline_equation", + "content": "Z^{m}" + }, + { + "bbox": [ + 46, + 412, + 290, + 509 + ], + "type": "text", + "content": " for m-th modality) are concatenated as the fused representation:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 62, + 517, + 288, + 534 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 517, + 288, + 534 + ], + "spans": [ + { + "bbox": [ + 62, + 517, + 288, + 534 + ], + "type": "interline_equation", + "content": "Z ^ {\\text {f u s e d}} = \\operatorname {c o n c a t} _ {C} (Z) = \\operatorname {c o n c a t} _ {C} \\left(\\left[ Z ^ {1}, \\dots , Z ^ {M} \\right]\\right) \\tag {3}", + "image_path": "c90d54577dce9c548cbf72c39cf1a45651b83c7b5e577eafce8c0fcac4326a56.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 542, + 287, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 542, + 287, + 567 + ], + "spans": [ + { + "bbox": [ + 46, + 542, + 287, + 567 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 542, + 287, + 567 + ], + "type": "inline_equation", + "content": "\\mathrm{concat}_C(*)" + }, + { + "bbox": [ + 46, + 542, + 287, + 567 + ], + "type": "text", + "content": " stands for channel-wise concatenation and " + }, + { + "bbox": [ + 46, + 542, + 287, + 567 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 46, + 542, + 287, + 567 + ], + "type": "text", + "content": " is the number of modalities." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 576, + 183, + 590 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 576, + 183, + 590 + ], + "spans": [ + { + "bbox": [ + 47, + 576, + 183, + 590 + ], + "type": "text", + "content": "3.3. Scene/Act Segmentation" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 595, + 288, + 643 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 595, + 288, + 643 + ], + "spans": [ + { + "bbox": [ + 46, + 595, + 288, + 643 + ], + "type": "text", + "content": "MEGA adopts a similar approach to previous works [8, 27, 45], where scene segmentation is framed as a binary classification task using a key-shot representation from a window of " + }, + { + "bbox": [ + 46, + 595, + 288, + 643 + ], + "type": "inline_equation", + "content": "2 \\times k + 1" + }, + { + "bbox": [ + 46, + 595, + 288, + 643 + ], + "type": "text", + "content": " shots (" + }, + { + "bbox": [ + 46, + 595, + 288, + 643 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 46, + 595, + 288, + 643 + ], + "type": "text", + "content": "-shots before and after):" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 127, + 653, + 287, + 668 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 127, + 653, + 287, + 668 + ], + "spans": [ + { + "bbox": [ + 127, + 653, + 287, + 668 + ], + "type": "interline_equation", + "content": "y _ {i} = \\varphi \\left(Z _ {i} ^ {\\text {f u s e d}}; \\theta_ {s}\\right) \\tag {4}", + "image_path": "ae262314e19d3af04f37fa7b055a766bd3d9b339fcac889f19ab239895d413eb.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "inline_equation", + "content": "y_{i}" + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "content": " is the logit prediction for the " + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "content": "-th key-shot. " + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\varphi" + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "content": " denotes the linear layer with learnable parameters " + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\theta_{s}" + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "content": " and a cross entropy loss is utilized [8, 27, 45]." + } + ] + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 323, + 289, + 533, + 415 + ], + "blocks": [ + { + "bbox": [ + 323, + 289, + 533, + 415 + ], + "lines": [ + { + "bbox": [ + 323, + 289, + 533, + 415 + ], + "spans": [ + { + "bbox": [ + 323, + 289, + 533, + 415 + ], + "type": "image", + "image_path": "38230f068fb726688e8efa1c12e99c38d33284de129a5743fdc87fdd883bef7d.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 426, + 547, + 535 + ], + "lines": [ + { + "bbox": [ + 304, + 426, + 547, + 535 + ], + "spans": [ + { + "bbox": [ + 304, + 426, + 547, + 535 + ], + "type": "text", + "content": "Figure 3: Illustration of Normalized Positional Encoding integration to the temporal tokens in one modality. This figure shows the integration of normalized Positional Encoding with 1) temporal shots for one modality and 2) bottleneck fusion tokens, where " + }, + { + "bbox": [ + 304, + 426, + 547, + 535 + ], + "type": "inline_equation", + "content": "L = 15" + }, + { + "bbox": [ + 304, + 426, + 547, + 535 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 426, + 547, + 535 + ], + "type": "inline_equation", + "content": "L_{n} = 3" + }, + { + "bbox": [ + 304, + 426, + 547, + 535 + ], + "type": "text", + "content": ". For (1) " + }, + { + "bbox": [ + 304, + 426, + 547, + 535 + ], + "type": "inline_equation", + "content": "i_{\\text{align}}" + }, + { + "bbox": [ + 304, + 426, + 547, + 535 + ], + "type": "text", + "content": " is obtained per shot index, " + }, + { + "bbox": [ + 304, + 426, + 547, + 535 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 426, + 547, + 535 + ], + "type": "text", + "content": ", and then each shot is integrated with normalized PE. For (2) each randomly initialized bottleneck token is integrated with normalized PE for its corresponding index." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "spans": [ + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "text", + "content": "The act segmentation task is formulated as " + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "inline_equation", + "content": "N_{tp}" + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "text", + "content": " linear prediction heads (" + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "inline_equation", + "content": "N_{tp}" + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "text", + "content": " is the number of turning points, and " + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "inline_equation", + "content": "\\theta_{a_n}" + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "text", + "content": " denotes the head parameters for " + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "text", + "content": "-th turning point [32]), for each individual shot from a temporal model that takes all the shots of the movie as input. To make a prediction at the " + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "text", + "content": "-th shot for the " + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "text", + "content": "-th act boundary (" + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "inline_equation", + "content": "n \\in \\{1, \\dots, N_{tp}\\}" + }, + { + "bbox": [ + 304, + 563, + 547, + 647 + ], + "type": "text", + "content": "), we use:" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 381, + 658, + 546, + 673 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 381, + 658, + 546, + 673 + ], + "spans": [ + { + "bbox": [ + 381, + 658, + 546, + 673 + ], + "type": "interline_equation", + "content": "y _ {i n} = \\varphi \\left(Z _ {i} ^ {\\text {f u s e d}}; \\theta_ {a _ {n}}\\right) \\tag {5}", + "image_path": "44c969c78536024fbc4aad8fad9f52171b03477aa8ad9e11dde500594c9a9161.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 689, + 546, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 689, + 546, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 689, + 546, + 715 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 689, + 546, + 715 + ], + "type": "inline_equation", + "content": "y_{in}" + }, + { + "bbox": [ + 304, + 689, + 546, + 715 + ], + "type": "text", + "content": " is the logit prediction for " + }, + { + "bbox": [ + 304, + 689, + 546, + 715 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 689, + 546, + 715 + ], + "type": "text", + "content": "-th shot and " + }, + { + "bbox": [ + 304, + 689, + 546, + 715 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 304, + 689, + 546, + 715 + ], + "type": "text", + "content": "-th turning point." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "23334" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 234, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 234, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 234, + 85 + ], + "type": "text", + "content": "3.4. Cross-domain Knowledge Transfer" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 90, + 288, + 198 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 90, + 288, + 198 + ], + "spans": [ + { + "bbox": [ + 46, + 90, + 288, + 198 + ], + "type": "text", + "content": "It is quite common during machine learning that certain modalities may lack annotations that are directly available in other modalities with different information granularity. To address this, we propose a cross-modality synchronization scheme that enables cross-modal distillation. We utilize this module for act segmentation where we aim to transfer act labels from synopsis sentences to movie-level timestamps. Importantly, our approach does not require additional information, such as screenplay [32], to bridge the gap." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "spans": [ + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": "Our knowledge distillation utilizes (1) an individual network to learn the synopsis-based act segmentation in a supervised manner with cross-entropy loss similar to [31]; and (2) a novel synchronization approach between synopsis and movie. For (1) we use the same architecture mentioned in Secs. 3.1, 3.2, setting " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "C_{\\mathrm{fused}}" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": " equal to the multimodal shot model setting. Additionally, similar to shot level linear prediction head (See Eq. 5), we use a sentence level linear prediction head, resulting in " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "q_{in}" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": " logits for the " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": "-th sentence of " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": "-th TP. A supervised Cross Entropy loss is used to learn the synopsis labels from predictions for each turning point " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "(\\mathcal{L}_{ce})" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": ". For (2) we seek a synchronization matrix " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "W \\in \\mathbb{R}^{L_{sh} \\times L_{syn}}" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": " between " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "L_{sh}" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": " shots and " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "L_{syn}" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": " synopsis sentences for a sample, where " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "w_{ij} = 1" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": " if the " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": "-th shot matches with the " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": "-th synopsis sentence and " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "w_{ij} = 0" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": ", otherwise. Assuming " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "F(:, \\theta)" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": " represents a parametric reward function (with parameters " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": "), to find " + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "inline_equation", + "content": "W" + }, + { + "bbox": [ + 46, + 198, + 290, + 402 + ], + "type": "text", + "content": ", we define an objective as:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 97, + 411, + 287, + 437 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 97, + 411, + 287, + 437 + ], + "spans": [ + { + "bbox": [ + 97, + 411, + 287, + 437 + ], + "type": "interline_equation", + "content": "\\max _ {W, \\theta} \\sum_ {i, j} w _ {i j} F (.; \\theta) - \\lambda \\sum_ {i, j} | w _ {i, j} | \\tag {6}", + "image_path": "a567889ad653697c4210004eb2b0be80c0d46e66de038929f5948c1ae18a765f.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 133, + 440, + 203, + 453 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 133, + 440, + 203, + 453 + ], + "spans": [ + { + "bbox": [ + 133, + 440, + 203, + 453 + ], + "type": "interline_equation", + "content": "s. t. 0 \\leq w _ {i j} \\leq 1", + "image_path": "88bfd0732f8e8ea563144f026814ae2ff2f242f9306130badadb1be1a3eb6f0f.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "spans": [ + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "text", + "content": "Expectation-Maximization algorithm is used to solve the objective in Eq. 6. We estimate the target variable " + }, + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "inline_equation", + "content": "W" + }, + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "text", + "content": " via fixed parameters (i.e., " + }, + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "text", + "content": ") in the E-step, and update the parameters while the target variable is known in the M-step." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 510, + 287, + 593 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 510, + 287, + 593 + ], + "spans": [ + { + "bbox": [ + 46, + 510, + 287, + 593 + ], + "type": "text", + "content": "E-step: Assuming " + }, + { + "bbox": [ + 46, + 510, + 287, + 593 + ], + "type": "inline_equation", + "content": "F(:,\\theta)" + }, + { + "bbox": [ + 46, + 510, + 287, + 593 + ], + "type": "text", + "content": " returns the similarity of input shot and synopsis sentence pair, the E-step has a closed form solution. In the E-step, following [26], we reduce the search space during optimization to only the pairs which are inside a diagonal boundary (see the proof for E-step and visualization of expected synchronization matrix for different examples in Appendix)." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 594, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 288, + 713 + ], + "type": "text", + "content": "M-step: Using all samples in a batch with " + }, + { + "bbox": [ + 46, + 594, + 288, + 713 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{SH}}" + }, + { + "bbox": [ + 46, + 594, + 288, + 713 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 594, + 288, + 713 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{SYN}}" + }, + { + "bbox": [ + 46, + 594, + 288, + 713 + ], + "type": "text", + "content": " total number of shots and synopsis sentences, we form their cosine similarity matrix of dimension " + }, + { + "bbox": [ + 46, + 594, + 288, + 713 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{SH}} \\times L_{\\mathrm{SYN}}" + }, + { + "bbox": [ + 46, + 594, + 288, + 713 + ], + "type": "text", + "content": ". For each query (synopsis sentence/movie shot, respectively), the positive keys (movie shot/synopsis sentence, respectively) are derived from the expectation step. Negative keys are the keys lying outside the diagonal boundary of the similarity matrix of shot-synopsis pairs for one movie [26], and all the keys from other movies within the batch. Here each query (synopsis sentence/movie shot, respectively) can have more than one" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 72, + 546, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 546, + 120 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 546, + 120 + ], + "type": "text", + "content": "positive key (movie shot/synopsis sentence, respectively) attached to it. Following [20], we adopt a modified version of the InfoNCE loss and combine it with the symmetric contrastive loss [34] as:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 315, + 128, + 546, + 198 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 128, + 546, + 198 + ], + "spans": [ + { + "bbox": [ + 315, + 128, + 546, + 198 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {L} _ {c} = - \\sum_ {i = 1} ^ {L _ {\\mathrm {S Y N}}} \\frac {1}{| \\hat {y} _ {i} |} \\sum_ {k = 1} ^ {L _ {\\mathrm {S H}}} \\hat {y} _ {i k} \\log \\frac {\\exp \\left(v _ {i} u _ {k} / \\tau\\right)}{\\sum_ {j = 1} ^ {L _ {\\mathrm {S H}}} \\exp \\left(v _ {i} u _ {j} / \\tau\\right)} - \\tag {7} \\\\ \\sum_ {i = 1} ^ {L _ {\\mathrm {S H}}} \\frac {1}{| \\hat {y} _ {i} ^ {T} |} \\sum_ {k = 1} ^ {L _ {\\mathrm {S Y N}}} \\hat {y} _ {i k} ^ {T} \\log \\frac {e x p (u _ {i} v _ {k} / \\tau)}{\\sum_ {j = 1} ^ {L _ {\\mathrm {S Y N}}} e x p (u _ {i} v _ {j} / \\tau)} \\\\ \\end{array}", + "image_path": "c3ce8b2defa9f6c5c7990ad27312b0c97192fc38c6b3d6ef98819eaff1d7877a.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "spans": [ + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "text", + "content": " is a learnable temperature parameter, and " + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "inline_equation", + "content": "\\hat{y}_{ij}" + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "text", + "content": " is a binary indicator of positive vs. negative pairs, " + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "inline_equation", + "content": "u_{i}" + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "text", + "content": " is the normalized feature for the " + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "text", + "content": "-th shot and " + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "inline_equation", + "content": "v_{i}" + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "text", + "content": " is the normalized feature for the " + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 204, + 546, + 251 + ], + "type": "text", + "content": "-th synopsis sentence." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 251, + 547, + 418 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 251, + 547, + 418 + ], + "spans": [ + { + "bbox": [ + 304, + 251, + 547, + 418 + ], + "type": "text", + "content": "Knowledge distillation: Knowledge distillation is used to transfer the knowledge available for the training samples on synopsis. The predictions from the synopsis model are mapped to shots using a matrix of their similarities as calculated in the maximization step, for each sample. The similarity scores for each shot are normalized along the synopsis sentences with softmax. The logit predictions from synopsis model are transferred to shots by multiplication with the normalized similarity matrix. A softmax along the shots is applied to the transferred logits to derive the probability scores for each shot. Following [31], we use a Kullback-Leibler divergence loss between predicted outputs for each shot and the transferred probabilities " + }, + { + "bbox": [ + 304, + 251, + 547, + 418 + ], + "type": "inline_equation", + "content": "(\\mathcal{L}_{kd})" + }, + { + "bbox": [ + 304, + 251, + 547, + 418 + ], + "type": "text", + "content": " (More details are provided in Appendix.)." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 419, + 546, + 443 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 419, + 546, + 443 + ], + "spans": [ + { + "bbox": [ + 305, + 419, + 546, + 443 + ], + "type": "text", + "content": "The cross-domain knowledge transfer module can be trained by simply adding the losses together as:" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 356, + 452, + 545, + 464 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 356, + 452, + 545, + 464 + ], + "spans": [ + { + "bbox": [ + 356, + 452, + 545, + 464 + ], + "type": "interline_equation", + "content": "\\mathcal {L} = \\alpha_ {c} \\mathcal {L} _ {c} + \\alpha_ {c e} \\mathcal {L} _ {c e} + \\alpha_ {k d} \\mathcal {L} _ {k d} \\tag {8}", + "image_path": "b8d421c9ac32d983a0b7215753b7eaf9761ef28b2972fa4a36fa29e84acd4089.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 474, + 545, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 474, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 304, + 474, + 545, + 498 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 474, + 545, + 498 + ], + "type": "inline_equation", + "content": "\\alpha_{c},\\alpha_{ce}" + }, + { + "bbox": [ + 304, + 474, + 545, + 498 + ], + "type": "text", + "content": " , and " + }, + { + "bbox": [ + 304, + 474, + 545, + 498 + ], + "type": "inline_equation", + "content": "\\alpha_{kd}" + }, + { + "bbox": [ + 304, + 474, + 545, + 498 + ], + "type": "text", + "content": " are hyperparameters that control the weights of the three losses." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 508, + 388, + 521 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 508, + 388, + 521 + ], + "spans": [ + { + "bbox": [ + 306, + 508, + 388, + 521 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 528, + 364, + 539 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 528, + 364, + 539 + ], + "spans": [ + { + "bbox": [ + 306, + 528, + 364, + 539 + ], + "type": "text", + "content": "4.1. Dataset" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 546, + 547, + 629 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 546, + 547, + 629 + ], + "spans": [ + { + "bbox": [ + 304, + 546, + 547, + 629 + ], + "type": "text", + "content": "We test our model on two commonly used dataset: Movienet-318 [18]: consists of 1100 movies, out of which 318 movies are annotated for the task of scene segmentation. The annotated dataset is split into 190, 64, and 64 movies for train, validation and test splits, respectively. We report the Average Precision (AP) and F1-score (F1) on the test split following previous work [35, 45]." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 629, + 547, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 547, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 547, + 712 + ], + "type": "text", + "content": "TRIPOD [32] includes 122 movies, split into 84, and 38 movies for train and test, respectively. This dataset includes the annotations of 6 act boundaries (\"the setup\", \"the new situation\", \"progress\", \"complications and higher stakes\", \"the final push\", \"the aftermath\") on the movie synopsis sentences for the training set, and on the movie screenplay scenes for the test set. The authors also have released soft" + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23335" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "content": "probability scores (silver annotations) for the training set, using " + }, + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "inline_equation", + "content": "[30]^1" + }, + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "content": ". To find the timestamps for the screenplay scenes in the movie, following [32] we used Dynamic Time Warping (DTW) to align the timed subtitles from the movie to the monologue lines in the screenplay. Following [32], we use total agreement (TA), partial agreement (PA) and distance (D) as evaluation metrics." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 163, + 180, + 175 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 163, + 180, + 175 + ], + "spans": [ + { + "bbox": [ + 47, + 163, + 180, + 175 + ], + "type": "text", + "content": "4.2. Implementation Details" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 180, + 288, + 276 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 180, + 288, + 276 + ], + "spans": [ + { + "bbox": [ + 46, + 180, + 288, + 276 + ], + "type": "text", + "content": "For scene segmentation: We train our model with 8 V100 GPUs with total batch size of 1024. The Adam [22] optimizer is used with learning rate of 1e-4. We train the model for 20 epochs. GeLU [16] is used as activation function by default, we use weighted cross entropy to balance the positive and negative samples at batch level. We choose shot sequence length of " + }, + { + "bbox": [ + 46, + 180, + 288, + 276 + ], + "type": "inline_equation", + "content": "17(k = 8)" + }, + { + "bbox": [ + 46, + 180, + 288, + 276 + ], + "type": "text", + "content": " following [27]. We set " + }, + { + "bbox": [ + 46, + 180, + 288, + 276 + ], + "type": "inline_equation", + "content": "L_{n} = 2" + }, + { + "bbox": [ + 46, + 180, + 288, + 276 + ], + "type": "text", + "content": " for this model." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "spans": [ + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "type": "text", + "content": "For act segmentation: We train our model with 4 V100 GPUs with total batch size of 4. The SGD optimizer is used with learning rate of 1e-3. We train the model for 10 epochs. " + }, + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "type": "text", + "content": " in Eq. 6 is empirically set differently for each synopsis sentence of each sample, by finding " + }, + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "type": "inline_equation", + "content": "99\\%" + }, + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "type": "text", + "content": " percentile of the similarity scores between the synopsis sentence and all the shots corresponding to that sample. " + }, + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "type": "inline_equation", + "content": "\\alpha_{c}, \\alpha_{ce}, \\alpha_{kd}" + }, + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "type": "text", + "content": " are set to 1, 1, and 10. We set " + }, + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "type": "inline_equation", + "content": "L_{n} = 100" + }, + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "type": "text", + "content": " for this the shot model and " + }, + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "type": "inline_equation", + "content": "L_{n} = 20" + }, + { + "bbox": [ + 46, + 277, + 289, + 408 + ], + "type": "text", + "content": " for the synopsis model. We use max pooling to aggregate the shot-level predictions to scene level. We use all shots from a video for act segmentation." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 415, + 133, + 426 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 415, + 133, + 426 + ], + "spans": [ + { + "bbox": [ + 47, + 415, + 133, + 426 + ], + "type": "text", + "content": "4.3. Main Results" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "spans": [ + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "text", + "content": "SoTA on Scene Segmentation. We first show MEGA outperforms previous SoTA on MovieNet318 [27] for scene segmentation " + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "inline_equation", + "content": "(+1.19\\%)" + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "text", + "content": " on AP and " + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "inline_equation", + "content": "+8.28\\%" + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "text", + "content": " on F1). With the same input visual features, MEGA outperforms previous SoTA [27] (Tab. " + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "inline_equation", + "content": "2 + 0.52\\%" + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "text", + "content": " on AP and " + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "inline_equation", + "content": "+3.69\\%" + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "text", + "content": " on F1), which indicates that the proposed approach is effective. Thanks to the proposed cross-modality fusion module, the MEGA generalizes and benefits from additional information extracted from visual signals. MEGA with 3 visual modalities (clip, place, and bassl) outperforms single modality model by " + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "inline_equation", + "content": "+0.67\\%" + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "text", + "content": " on AP and " + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "inline_equation", + "content": "+4.59\\%" + }, + { + "bbox": [ + 46, + 433, + 289, + 612 + ], + "type": "text", + "content": " on F1, which shows the proposed fusion works as expected. It is worth mentioning that the proposed method is scalable and generalizes to various number of modalities at different scales, which makes it flexible for real-world applications." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 613, + 288, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 613, + 288, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 613, + 288, + 696 + ], + "type": "text", + "content": "SoTA on Act Segmentation. We then show that MEGA establishes the new SoTA performance on act segmentation on TRIPOD dataset (Tab. 3). We first show that MEGA outperforms previous SoTA on TRIPOD [32] dataset With only visual signals as input. Comparing to other works that take textural inputs [29, 32], MEGA is able to achieve better performance. Furthermore, in real-world applications, the" + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 317, + 70, + 536, + 239 + ], + "blocks": [ + { + "bbox": [ + 317, + 70, + 536, + 239 + ], + "lines": [ + { + "bbox": [ + 317, + 70, + 536, + 239 + ], + "spans": [ + { + "bbox": [ + 317, + 70, + 536, + 239 + ], + "type": "table", + "html": "
ApproachModalityPretrained onAP↑ [%]FI↑ [%]
Random [35]--8.2-
Visual only input
GraphCut [36]VPlaces [50]14.1-
SCSA [7]VPlaces [50]14.7-
DP [13]VPlaces [50]15.5-
Grouping [37]VPlaces [50]17.6-
StoryGraph [41]VPlaces [50]25.1-
Siamese [4]VPlaces [50]28.1-
LGSS [35]VPlaces [35]39.0-
LGSS [35]VCast [17,48]15.9-
LGSS [35]VAction [11]32.1-
ShotCoL [8]†VMovienet [18]52.8949.17
SCRL [45]VMovienet [18]54.8251.43
BaSSL [27]VMovienet [18]57.447.02
MEGAVMovienet [18]57.9250.71
MEGAVM+P+I58.5955.30
", + "image_path": "a7e5296b2fdb582714b90b74c76231d55e82aead0917f1cb90dda76fe70d2c29.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 244, + 547, + 281 + ], + "lines": [ + { + "bbox": [ + 304, + 244, + 547, + 281 + ], + "spans": [ + { + "bbox": [ + 304, + 244, + 547, + 281 + ], + "type": "text", + "content": "Table 2: Scene boundary detection: comparison with SoTA. " + }, + { + "bbox": [ + 304, + 244, + 547, + 281 + ], + "type": "inline_equation", + "content": "\\dagger" + }, + { + "bbox": [ + 304, + 244, + 547, + 281 + ], + "type": "text", + "content": "means the numbers are copied from [45]. M+P+I denotes pre-trained on Movienet [18], Places [50] and IMDB." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 291, + 547, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 291, + 547, + 434 + ], + "spans": [ + { + "bbox": [ + 304, + 291, + 547, + 434 + ], + "type": "text", + "content": "visual input (the video) is often easier to obtain than textual inputs such as screenplay [32]. We further show that MEGA* (Tab. 3), which swaps our synchronization module to use similar synchronization as SoTA [32], outperforms GRAPHTP, which demonstrates the effectiveness of proposed approach including the alignment and fusion modules. It is worth mentioning that, with multiple features extracted from visual media modality alone, MEGA outperforms previous SOTA which makes the proposed model applicable for real-world scenarios, as it is usually harder to get additional media modalities (e.g., screenplay) which are used in other works." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 435, + 548, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 435, + 548, + 567 + ], + "spans": [ + { + "bbox": [ + 304, + 435, + 548, + 567 + ], + "type": "text", + "content": "By further aggregating the results from text input, MEGA establishes the new state-of-the-art on TRIPOD dataset (Tab. 3). MEGA almost doubles the performance of previous work [29, 32] with " + }, + { + "bbox": [ + 304, + 435, + 548, + 567 + ], + "type": "inline_equation", + "content": "+5.51\\%" + }, + { + "bbox": [ + 304, + 435, + 548, + 567 + ], + "type": "text", + "content": " TA, " + }, + { + "bbox": [ + 304, + 435, + 548, + 567 + ], + "type": "inline_equation", + "content": "+9.15\\%" + }, + { + "bbox": [ + 304, + 435, + 548, + 567 + ], + "type": "text", + "content": " PA, " + }, + { + "bbox": [ + 304, + 435, + 548, + 567 + ], + "type": "inline_equation", + "content": "-\\%0.81" + }, + { + "bbox": [ + 304, + 435, + 548, + 567 + ], + "type": "text", + "content": " D. This shows the proposed multimodal fusion scales and generalizes well to multiple modalities. The cross-modality distillation also works robustly for various settings. We noticed that adding the acoustic features is not always helpful to the performance (Tab. 3), probably because acoustic information provides redundant or not useful information for the task of act boundary segmentation." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 574, + 374, + 586 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 574, + 374, + 586 + ], + "spans": [ + { + "bbox": [ + 306, + 574, + 374, + 586 + ], + "type": "text", + "content": "4.4. Ablations" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 594, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 547, + 713 + ], + "type": "text", + "content": "We perform ablations to examine the effectiveness of major building blocks of MEGA. We use features extracted from visual media modality (for scene segmentation: clip, place, Bassl and for act segmentation: clip, appr, action, place), with the proposed normalized positional encoding, multi-modality bottleneck fusion, and cross-modality synchronization by default unless specified. The training and evaluation follows same protocols as mentioned in Sec. 4.3. Alignment Positional Encoding. We report the ablations on Alignment PE in Tab. 4a. We notice that the proposed" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 58, + 702, + 251, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 251, + 713 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 251, + 713 + ], + "type": "text", + "content": "1https://github.com/ppapalampidi/GraphTP" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 293, + 749, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 318, + 757 + ], + "type": "text", + "content": "23336" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 69, + 294, + 258 + ], + "blocks": [ + { + "bbox": [ + 50, + 69, + 294, + 258 + ], + "lines": [ + { + "bbox": [ + 50, + 69, + 294, + 258 + ], + "spans": [ + { + "bbox": [ + 50, + 69, + 294, + 258 + ], + "type": "table", + "html": "
ApproachModalityModality for synch.TA↑ [%]PA↑ [%]D↓ [%]
Random (Evenly dist.) [32]-T*4.826.9512.35
Theory [14, 30]-T*4.416.3211.03
Distribution position [32]-T*5.597.3710.74
Single modality input
TEXTRANK [25]T*T*6.1810.0017.77
SCENESUM [10]T*T*4.417.8916.86
TAM [29]T*T*7.949.479.42
GRAPHTP [32]T*T*6.7610.009.62
MEGA*VT*10.5114.548.98
MEGAVV13.9320.729.19
Multi-modality input
TEXTRANK [25]T*+A+VT*6.1810.0018.90
SCENESUM [10]T*+A+VT*6.7611.0518.93
TAM [29]T*+A+VT*7.3610.0010.01
GRAPHTP [32]T*+A+VT*9.1212.639.77
MEGA*T+VT*11.1415.208.96
MEGAT+VT+V14.6321.788.96
MEGA*T+A+VT*10.0014.088.96
MEGAT+A+VT+A+V14.1922.109.68
", + "image_path": "c1aed1c7f72e851cd75da5b3fd8eda56b55ae3a9b0f9089d95856705e232e2e5.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 325, + 287, + 492 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 325, + 287, + 492 + ], + "spans": [ + { + "bbox": [ + 46, + 325, + 287, + 492 + ], + "type": "text", + "content": "alignment PE consistently improves the performance on both scene and act segmentation tasks, while act segmentation benefits more significantly from it. This is because of two reasons: 1) inputs to the act segmentation model have variable lengths (all the shots from a video) as opposed to scene segmentation which has fixed length inputs, hence the alignment PE adds more information to the act segmentation model; and 2) Alignment PE is shared across all modalities and fusion layer and its absence causes more harm to sequences with longer lengths, as act segmentation takes longer shot sequences (entire video) compared to scene segmentation (17 shots). Overall, the drop in performance indicates that the proposed Alignment P.E. is an essential component for video segmentation tasks." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 494, + 287, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 494, + 287, + 590 + ], + "spans": [ + { + "bbox": [ + 46, + 494, + 287, + 590 + ], + "type": "text", + "content": "We further remove the proposed Alignment PE from bottleneck fusion tokens and show results in Tab. 4b. We observe a performance drop when removing the Alignment PE. It is worth mentioning that the performance drop is more noticeable when multiple modalities are involved, (e.g. V + T model), which suggests that the information from subtitles requires precise temporal alignment in order to be effective during multimodal fusion." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 592, + 288, + 664 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 592, + 288, + 664 + ], + "spans": [ + { + "bbox": [ + 46, + 592, + 288, + 664 + ], + "type": "text", + "content": "Multimodal Fusion Strategies. Tab. 4c compares our proposed fusion tokens with the commonly used late fusion strategy. The results show that the temporal bottleneck fusion clearly outperforms late fusion, demonstrating the effectiveness of aligned bottleneck tokens in improving the performance across both tasks." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 665, + 289, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 289, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 289, + 714 + ], + "type": "text", + "content": "Different Input Modalities. We study the impact of different modalities by removing them from the input and present results on scene segmentation and act segmentation. In scene segmentation (Tab. 4d), we find that the Bassl feature fol" + } + ] + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 313, + 70, + 539, + 125 + ], + "blocks": [ + { + "bbox": [ + 46, + 266, + 289, + 315 + ], + "lines": [ + { + "bbox": [ + 46, + 266, + 289, + 315 + ], + "spans": [ + { + "bbox": [ + 46, + 266, + 289, + 315 + ], + "type": "text", + "content": "Table 3: TP identification: comparison with SoTA. MEGA* denotes the MEGA using the same synchronization as [30] for fair comparison. T*,V,T,A denote Textual-screenplay, Visual, Textual-subtitle and Acoustic features, respectively." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 313, + 70, + 539, + 125 + ], + "lines": [ + { + "bbox": [ + 313, + 70, + 539, + 125 + ], + "spans": [ + { + "bbox": [ + 313, + 70, + 539, + 125 + ], + "type": "table", + "html": "
caseScene Seg.Act Segmentation
AP↑TA↑PA↑D↓
w/o align. PE57.775.297.3731.04
w. align. PE58.5913.9320.729.19
", + "image_path": "05bcf01fec3972f025ce50ea948ebdf6a9e75feaaa57f485de8857fe122aae4b.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 313, + 148, + 539, + 223 + ], + "blocks": [ + { + "bbox": [ + 341, + 128, + 511, + 139 + ], + "lines": [ + { + "bbox": [ + 341, + 128, + 511, + 139 + ], + "spans": [ + { + "bbox": [ + 341, + 128, + 511, + 139 + ], + "type": "text", + "content": "(a) Effectiveness of Alignment Positional Encoding." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 313, + 148, + 539, + 223 + ], + "lines": [ + { + "bbox": [ + 313, + 148, + 539, + 223 + ], + "spans": [ + { + "bbox": [ + 313, + 148, + 539, + 223 + ], + "type": "table", + "html": "
casemodalityScene Seg.Act Segmentation
AP↑TA↑PA↑D↓
w/o align.PEV58.3113.6020.539.47
w. align.PEV58.5913.9320.729.19
w/o align.PEV + T-13.0120.139.56
w. align.PEV + T-14.6321.788.96
", + "image_path": "28345670680c5cf75fca43424e29c82edd53847a61eb45440e65b24d2523e422.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 315, + 245, + 537, + 300 + ], + "blocks": [ + { + "bbox": [ + 309, + 225, + 542, + 236 + ], + "lines": [ + { + "bbox": [ + 309, + 225, + 542, + 236 + ], + "spans": [ + { + "bbox": [ + 309, + 225, + 542, + 236 + ], + "type": "text", + "content": "(b) Effectiveness of Normalized Positional Encoding in bottleneck tokens." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 315, + 245, + 537, + 300 + ], + "lines": [ + { + "bbox": [ + 315, + 245, + 537, + 300 + ], + "spans": [ + { + "bbox": [ + 315, + 245, + 537, + 300 + ], + "type": "table", + "html": "
MM. integ. typeScene Seg.Act Segmentation
AP↑TA↑PA↑D↓
LateFusion58.2412.5719.2110.00
Bottleneck58.5913.9320.729.19
", + "image_path": "d75349a0e3b86b6a63f1c60b3ad16a0a559b636b34cc52836cc5c8fd0e88c650.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 310, + 323, + 385, + 395 + ], + "blocks": [ + { + "bbox": [ + 371, + 304, + 481, + 314 + ], + "lines": [ + { + "bbox": [ + 371, + 304, + 481, + 314 + ], + "spans": [ + { + "bbox": [ + 371, + 304, + 481, + 314 + ], + "type": "text", + "content": "(c) Multi-modal fusion strategies." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 310, + 323, + 385, + 395 + ], + "lines": [ + { + "bbox": [ + 310, + 323, + 385, + 395 + ], + "spans": [ + { + "bbox": [ + 310, + 323, + 385, + 395 + ], + "type": "table", + "html": "
changeAP↑
-clip58.09
-place57.51
-bassl51.88
-clip-place57.92
-58.59
", + "image_path": "d1c20b98b9e98e1c850799d1d6d5bcbce4dab6f81d9ec84c37b8be02515d9cce.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_body" + } + ], + "index": 12 + }, + { + "type": "table", + "bbox": [ + 422, + 323, + 542, + 395 + ], + "blocks": [ + { + "bbox": [ + 306, + 397, + 388, + 417 + ], + "lines": [ + { + "bbox": [ + 306, + 397, + 388, + 417 + ], + "spans": [ + { + "bbox": [ + 306, + 397, + 388, + 417 + ], + "type": "text", + "content": "(d) Impact from input modalities on scene seg." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 422, + 323, + 542, + 395 + ], + "lines": [ + { + "bbox": [ + 422, + 323, + 542, + 395 + ], + "spans": [ + { + "bbox": [ + 422, + 323, + 542, + 395 + ], + "type": "table", + "html": "
changeTA↑PA↑D↓
-clip6.0910.6621.81
-place13.5719.879.22
-action13.3120.2010.38
-appr13.4220.598.85
-13.9320.729.19
+subtitle14.6321.788.96
", + "image_path": "2a7945fc8f16976c443874bb23b25f5d708ae9cc2c2ca685f7ed1cc1c17d0985.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "table_body" + } + ], + "index": 14 + }, + { + "type": "table", + "bbox": [ + 318, + 426, + 535, + 478 + ], + "blocks": [ + { + "bbox": [ + 419, + 398, + 545, + 417 + ], + "lines": [ + { + "bbox": [ + 419, + 398, + 545, + 417 + ], + "spans": [ + { + "bbox": [ + 419, + 398, + 545, + 417 + ], + "type": "text", + "content": "(e) Impact from input modalities on act segmentation." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 318, + 426, + 535, + 478 + ], + "lines": [ + { + "bbox": [ + 318, + 426, + 535, + 478 + ], + "spans": [ + { + "bbox": [ + 318, + 426, + 535, + 478 + ], + "type": "table", + "html": "
synopsis synch. byM for synch.TA↑PA↑D↓
[30]T*10.5114.548.98
MEGAV13.9320.729.19
MEGAV + T14.6321.788.96
", + "image_path": "644c0ce660192368bb48e71aac304b5025c263f1b21c1a84c4b90ee244f6484c.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "table_body" + } + ], + "index": 16 + }, + { + "type": "table", + "bbox": [ + 310, + 510, + 545, + 555 + ], + "blocks": [ + { + "bbox": [ + 313, + 479, + 538, + 500 + ], + "lines": [ + { + "bbox": [ + 313, + 479, + 538, + 500 + ], + "spans": [ + { + "bbox": [ + 313, + 479, + 538, + 500 + ], + "type": "text", + "content": "(f) Impact of Synchronization with multimodal video features on act segmentation." + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 310, + 510, + 545, + 555 + ], + "lines": [ + { + "bbox": [ + 310, + 510, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 310, + 510, + 545, + 555 + ], + "type": "table", + "html": "
ApproachFeature Set Pretrained onAP↑Params↓SPS↑
BaSSL [27]Movienet57.415.77M6244.99
LGSS [35]M+P+I52.9366.16M206.36
MEGAM+P+I58.5967.57M1736.13
", + "image_path": "0ba289f1200482b90d3197b98ce2f05143e8dafcbec12bacf67dc207920eab1a.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "table_body" + } + ], + "index": 18 + }, + { + "type": "table", + "bbox": [ + 310, + 587, + 548, + 632 + ], + "blocks": [ + { + "bbox": [ + 306, + 558, + 548, + 578 + ], + "lines": [ + { + "bbox": [ + 306, + 558, + 548, + 578 + ], + "spans": [ + { + "bbox": [ + 306, + 558, + 548, + 578 + ], + "type": "text", + "content": "(g) Impact from feature set and model size on scene seg. SPS denotes # of samples per second." + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 310, + 587, + 548, + 632 + ], + "lines": [ + { + "bbox": [ + 310, + 587, + 548, + 632 + ], + "spans": [ + { + "bbox": [ + 310, + 587, + 548, + 632 + ], + "type": "table", + "html": "
ApproachFeature SetTA↑PA↑D↓Params↓SPS↑
GRAPHTP [32]Set1 [32]9.1212.639.770.745M25.40
GRAPHTP [32]Set24.727.379.696.78M14.36
MEGASet214.1922.109.686.78M18.24
", + "image_path": "a2065619740587798ecfc8464a7b686a81c1d6d8467fbbaf371e284134e23408.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "table_body" + } + ], + "index": 20 + }, + { + "bbox": [ + 306, + 636, + 548, + 666 + ], + "lines": [ + { + "bbox": [ + 306, + 636, + 548, + 666 + ], + "spans": [ + { + "bbox": [ + 306, + 636, + 548, + 666 + ], + "type": "text", + "content": "(h) Impact from feature set and model size on act seg. Set1 includes Visual (appr), Audio (YAMNet), Textual (script-USE). Set2 has Visual (appr,clip,action.place), Audio (audio), Textual (text from subtitle)." + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 324, + 667, + 525, + 679 + ], + "lines": [ + { + "bbox": [ + 324, + 667, + 525, + 679 + ], + "spans": [ + { + "bbox": [ + 324, + 667, + 525, + 679 + ], + "type": "text", + "content": "Table 4: Ablation studies on MEGA components." + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 689, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 547, + 713 + ], + "type": "text", + "content": "lowed by place are the most important. This is because the BaSSL [27] model is pretrained for scene segmenta-" + } + ] + } + ], + "index": 23 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23337" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "content": "tion and place consistency is critical for scene segmentation. In act segmentation (Tab. 4e), we find that the CLIP feature pre-trained on IMDB, followed by subtitle are the most important features. This is because the clip model is pre-trained on abstract concepts (e.g. genre, micro genre, character type and coarse key places), thus the CLIP feature contains richer semantics, and subtitle provides complementary rich semantic information. These high level semantics are considered useful for act segmentation. Overall, when all the features are included, the model is able to leverage the unique information provided by each feature and yields the best performance." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 217, + 289, + 408 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 217, + 289, + 408 + ], + "spans": [ + { + "bbox": [ + 46, + 217, + 289, + 408 + ], + "type": "text", + "content": "Cross-modality Synchronization. Tab. 4f studies the effectiveness of the proposed cross modality synchronization on act segmentation. To establish a baseline, we use the probability scores provided by [32] and derived by aligning synopsis sentences to scenes using screenplay [30] (T* in Tab. 4f denotes screenplay). For a fair comparison, we repeat the scores provided for each scene on all of its shots and then re-normalize2. MEGA with visual only input outperforms [30] across two metrics (PA and TA) and when we add the subtitle features (T in Tab. 4f denotes subtitle), MEGA outperforms [30] across all the metrics. The results demonstrate that the proposed cross-domain synchronization works effectively and generalize well to various modalities. It is worth mentioning that the proposed method generates act segmentation without requiring the screenplay, which makes it practical for various industrial applications." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 408, + 289, + 504 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 408, + 289, + 504 + ], + "spans": [ + { + "bbox": [ + 46, + 408, + 289, + 504 + ], + "type": "text", + "content": "Impact of Feature Set. In Tab. 4g, we examine whether feature set plays an outsized role in MEGA's improved performance over other methods. On the same feature set of " + }, + { + "bbox": [ + 46, + 408, + 289, + 504 + ], + "type": "inline_equation", + "content": "\\mathrm{M} + \\mathrm{P} + \\mathrm{I}" + }, + { + "bbox": [ + 46, + 408, + 289, + 504 + ], + "type": "text", + "content": ", we outperform LGSS [35] while only introducing a small number of additional parameters. BaSSL [27] achieves slightly lower performance using only Movienet features, indicating that the use of additional features is not the primary reason for our improved performance." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 505, + 289, + 589 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 505, + 289, + 589 + ], + "spans": [ + { + "bbox": [ + 46, + 505, + 289, + 589 + ], + "type": "text", + "content": "Impact of Model Size. We finally look into the impact of model size on the performance. To establish the fair comparison, we first expand GRAPHTP [32] which shares the same input as MEGA to roughly the same number of parameters as MEGA. Our results on act segmentation (Tab. 4h) show that MEGA outperforms the previous SoTA, GRAPHTP [32], which indicates the MEGA has efficient and effective design." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 597, + 201, + 609 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 597, + 201, + 609 + ], + "spans": [ + { + "bbox": [ + 47, + 597, + 201, + 609 + ], + "type": "text", + "content": "4.5. Fusion with Audio Modality" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 616, + 288, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 616, + 288, + 665 + ], + "spans": [ + { + "bbox": [ + 46, + 616, + 288, + 665 + ], + "type": "text", + "content": "We also experimented with the effect of adding audio. Movienet [18] has released Short Time Fourier Transform (STFT) features extracted from audio files. We use the same audio backbone as [35]. However, by adding audio features" + } + ] + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 336, + 69, + 535, + 182 + ], + "blocks": [ + { + "bbox": [ + 336, + 69, + 535, + 182 + ], + "lines": [ + { + "bbox": [ + 336, + 69, + 535, + 182 + ], + "spans": [ + { + "bbox": [ + 336, + 69, + 535, + 182 + ], + "type": "table", + "html": "
ApproachModalityAP↑ [%]
LGSS [35]V(place)39.00
ShotCoL [8];V46.77
SCRL [45]V54.55
MEGAV(place,clip,bassl)58.59
LGSS [35]V(place)+A43.4
ShotCoL [8];V+A44.32
SCRL [45]V+A50.80
MEGAV(place,clip,bassl)+A55.36
", + "image_path": "8941c641ad24748221db938432dc0d1c6a0b36306d6331e7d06a22cc695f815a.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 190, + 545, + 202 + ], + "lines": [ + { + "bbox": [ + 305, + 190, + 545, + 202 + ], + "spans": [ + { + "bbox": [ + 305, + 190, + 545, + 202 + ], + "type": "text", + "content": "Table 5: Scene Seg. with audio. " + }, + { + "bbox": [ + 305, + 190, + 545, + 202 + ], + "type": "inline_equation", + "content": "\\ddagger" + }, + { + "bbox": [ + 305, + 190, + 545, + 202 + ], + "type": "text", + "content": "denotes copying from [45]." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 209, + 547, + 390 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 209, + 547, + 390 + ], + "spans": [ + { + "bbox": [ + 304, + 209, + 547, + 390 + ], + "type": "text", + "content": "in MEGA, we see a drop in the performance (see Tab. 5). Although [8, 35] have shown improvements across multiple models by adding the audio modality across Movienet-150 dataset [35] (where the split is not publicly available) or a private dataset: AdCuepoints [8], Wu et al. [45] have observed a similar trend as our experiments, where adding the released audio features in Movienet [18] to SCRL [45] and ShotCoL [8] drops the performance (see Tab. 5). Possible reasons can be 1) the audio features published by Movienet via STFT" + }, + { + "bbox": [ + 304, + 209, + 547, + 390 + ], + "type": "inline_equation", + "content": "^3" + }, + { + "bbox": [ + 304, + 209, + 547, + 390 + ], + "type": "text", + "content": " are an incomplete view of the shot from audio modality either in representation or in terms of the audio chunk from each shot they used, and the raw audio files are not available. 2) our multimodal fusion strategy cannot exploit the possible complementary information or filter the harmful or confusing signals from the audio modality." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 399, + 459, + 411 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 399, + 459, + 411 + ], + "spans": [ + { + "bbox": [ + 305, + 399, + 459, + 411 + ], + "type": "text", + "content": "5. Discussion and Conclusion" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 419, + 547, + 502 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 419, + 547, + 502 + ], + "spans": [ + { + "bbox": [ + 304, + 419, + 547, + 502 + ], + "type": "text", + "content": "Limitations. The explorations in this work are limited to appearance, location, activity, acoustic and textual features. For long movie segmentation, however, providing the name of actors (tabular data) and having a specific component for actor identification in the movie can help both the synchronization and the act/scene segmentation models. We will explore the use of this data." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 503, + 547, + 611 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 503, + 547, + 611 + ], + "spans": [ + { + "bbox": [ + 304, + 503, + 547, + 611 + ], + "type": "text", + "content": "The results demonstrated that richer semantic representations from the clip features enhanced the performance for long video segmentation. To obtain better performing representations for long video understanding one can use large amount of unlabeled data with carefully selected pretext tasks for understanding long context. We will investigate the use of SSL to train a rich multimodal representation from videos and will examine the learned representations across multiple long video understanding tasks." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 611, + 547, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 611, + 547, + 696 + ], + "spans": [ + { + "bbox": [ + 304, + 611, + 547, + 696 + ], + "type": "text", + "content": "Conclusion. This paper introduces MEGA, a unified solution for long video segmentation. Our design of normalized positional encoding, and their integration into fusion tokens allows MEGA to learn consistent patterns from inputs with variable lengths and efficiently and effectively align and fuse them across different modalities. Our synchronization schema further allows the use of rich multimodal tokens to" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 46, + 673, + 288, + 714 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 673, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 673, + 288, + 714 + ], + "type": "text", + "content": "2This strategy maintains the rank of probability scores for different turning points across different segments of the movie, and is consistent with the max-pooling of prediction scores on shot level to derive the scene level predictions during evaluation (see Sec. 4.2)." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 315, + 702, + 525, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 702, + 525, + 712 + ], + "spans": [ + { + "bbox": [ + 315, + 702, + 525, + 712 + ], + "type": "text", + "content": "3https://github.com/movienet/movienet-tools" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "text", + "content": "23338" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 120 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 120 + ], + "type": "text", + "content": "be used in transferring the labels from synopsis sentences to movie shots, facilitating the knowledge distillation from synopses to movies. MEGA achieves state-of-the-art performance compared with previous works." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 129, + 105, + 141 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 129, + 105, + 141 + ], + "spans": [ + { + "bbox": [ + 48, + 129, + 105, + 141 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 149, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 53, + 149, + 287, + 181 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 149, + 287, + 181 + ], + "spans": [ + { + "bbox": [ + 53, + 149, + 287, + 181 + ], + "type": "text", + "content": "[1] Sentence-transformers model: all-minilm-l6-v2 from Hugging Face. https://huggingface.co/sentence-transformers/all-MiniLM-L6-v2.3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 183, + 288, + 226 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 183, + 288, + 226 + ], + "spans": [ + { + "bbox": [ + 53, + 183, + 288, + 226 + ], + "type": "text", + "content": "[2] Yuki Asano, Mandela Patrick, Christian Rupprecht, and Andrea Vedaldi. Labelling unlabelled videos from scratch with multi-modal self-supervision. Advances in Neural Information Processing Systems, 33:4660-4671, 2020. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 54, + 228, + 288, + 270 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 228, + 288, + 270 + ], + "spans": [ + { + "bbox": [ + 54, + 228, + 288, + 270 + ], + "type": "text", + "content": "[3] Yusuf Aytar, Carl Vondrick, and Antonio Torralba. Soundnet: Learning sound representations from unlabeled video. Advances in neural information processing systems, 29, 2016. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 272, + 288, + 315 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 272, + 288, + 315 + ], + "spans": [ + { + "bbox": [ + 53, + 272, + 288, + 315 + ], + "type": "text", + "content": "[4] Lorenzo Baraldi, Costantino Grana, and Rita Cucchiara. A deep siamese network for scene detection in broadcast videos. In Proceedings of the 23rd ACM international conference on Multimedia, pages 1199-1202, 2015. 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 316, + 288, + 346 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 316, + 288, + 346 + ], + "spans": [ + { + "bbox": [ + 53, + 316, + 288, + 346 + ], + "type": "text", + "content": "[5] Jessica Brody. Save the Cat! Writes a Novel: The Last Book On Novel Writing You'll Ever Need. Ten Speed Press, 2018. 2, 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 350, + 288, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 350, + 288, + 392 + ], + "spans": [ + { + "bbox": [ + 53, + 350, + 288, + 392 + ], + "type": "text", + "content": "[6] Joao Carreira and Andrew Zisserman. Quo vadis, action recognition? a new model and the kinetics dataset. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 6299-6308, 2017. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 394, + 288, + 436 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 394, + 288, + 436 + ], + "spans": [ + { + "bbox": [ + 53, + 394, + 288, + 436 + ], + "type": "text", + "content": "[7] Vasileios T Chasanis, Aristidis C Likas, and Nikolaos P Galatsanos. Scene detection in videos using shot clustering and sequence alignment. IEEE transactions on multimedia, 11(1):89-100, 2008. 6" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 437, + 288, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 437, + 288, + 491 + ], + "spans": [ + { + "bbox": [ + 53, + 437, + 288, + 491 + ], + "type": "text", + "content": "[8] Shixing Chen, Xiaohan Nie, David Fan, Dongqing Zhang, Visual Bhat, and Raffay Hamid. Shot contrastive self-supervised learning for scene boundary detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9796-9805, 2021. 1, 2, 4, 6, 8" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 493, + 287, + 558 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 493, + 287, + 558 + ], + "spans": [ + { + "bbox": [ + 53, + 493, + 287, + 558 + ], + "type": "text", + "content": "[9] Zi-Yi Dou, Yichong Xu, Zhe Gan, Jianfeng Wang, Shuohang Wang, Lijuan Wang, Chenguang Zhu, Pengchuan Zhang, Lu Yuan, Nanyun Peng, et al. An empirical study of training end-to-end vision-and-language transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18166-18176, 2022. 1, 2, 3, 4" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 559, + 288, + 613 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 559, + 288, + 613 + ], + "spans": [ + { + "bbox": [ + 48, + 559, + 288, + 613 + ], + "type": "text", + "content": "[10] Philip Gorinski and Mirella Lapata. Movie script summarization as graph-based scene extraction. In Proceedings of the 2015 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pages 1066-1076, 2015. 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 615, + 288, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 615, + 288, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 615, + 288, + 689 + ], + "type": "text", + "content": "[11] Chunhui Gu, Chen Sun, David A Ross, Carl Vondrick, Caroline Pantofaru, Yeqing Li, Sudheendra Vijayanarasimhan, George Toderici, Susanna Ricco, Rahul Sukthankar, et al. Ava: A video dataset of spatio-temporally localized atomic visual actions. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 6047-6056, 2018. 6" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 691, + 288, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 288, + 713 + ], + "type": "text", + "content": "[12] Saurabh Gupta, Judy Hoffman, and Jitendra Malik. Cross modal distillation for supervision transfer. In Proceedings of" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 326, + 73, + 547, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 547, + 95 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 547, + 95 + ], + "type": "text", + "content": "the IEEE conference on computer vision and pattern recognition, pages 2827-2836, 2016. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 97, + 547, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 97, + 547, + 140 + ], + "spans": [ + { + "bbox": [ + 308, + 97, + 547, + 140 + ], + "type": "text", + "content": "[13] Bo Han and Weiguo Wu. Video scene segmentation using a novel boundary evaluation criterion and dynamic programming. In 2011 IEEE International conference on multimedia and expo, pages 1-6. IEEE, 2011. 6" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 141, + 547, + 174 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 141, + 547, + 174 + ], + "spans": [ + { + "bbox": [ + 308, + 141, + 547, + 174 + ], + "type": "text", + "content": "[14] Michael Hauge. Storytelling Made Easy: Persuade and Transform Your Audiences, Buyers, And Clients-Simply, Quickly, and Profitably. BookBaby, 2017. 1, 2, 3, 7" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 175, + 547, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 175, + 547, + 228 + ], + "spans": [ + { + "bbox": [ + 308, + 175, + 547, + 228 + ], + "type": "text", + "content": "[15] Lisa Anne Hendricks, John Mellor, Rosalia Schneider, Jean-Baptiste Alayrac, and Aida Nematzadeh. Decoupling the role of data, attention, and losses in multimodal transformers. Transactions of the Association for Computational Linguistics, 9:570-585, 2021. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 231, + 546, + 252 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 231, + 546, + 252 + ], + "spans": [ + { + "bbox": [ + 308, + 231, + 546, + 252 + ], + "type": "text", + "content": "[16] Dan Hendrycks and Kevin Gimpel. Gaussian error linear units (gelus). arXiv preprint arXiv:1606.08415, 2016. 6" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 254, + 547, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 254, + 547, + 297 + ], + "spans": [ + { + "bbox": [ + 308, + 254, + 547, + 297 + ], + "type": "text", + "content": "[17] Qingqiu Huang, Yu Xiong, and Dahua Lin. Unifying identification and context learning for person recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 2217-2225, 2018. 6" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 300, + 547, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 300, + 547, + 342 + ], + "spans": [ + { + "bbox": [ + 308, + 300, + 547, + 342 + ], + "type": "text", + "content": "[18] Qingqiu Huang, Yu Xiong, Anyi Rao, Jiaze Wang, and Dahua Lin. Movienet: A holistic dataset for movie understanding. In European Conference on Computer Vision, pages 709-727. Springer, 2020. 2, 5, 6, 8" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 344, + 547, + 397 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 344, + 547, + 397 + ], + "spans": [ + { + "bbox": [ + 308, + 344, + 547, + 397 + ], + "type": "text", + "content": "[19] Andrew Jaegle, Felix Gimeno, Andy Brock, Oriol Vinyals, Andrew Zisserman, and Joao Carreira. Perceiver: General perception with iterative attention. In International conference on machine learning, pages 4651-4664. PMLR, 2021. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 399, + 547, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 399, + 547, + 453 + ], + "spans": [ + { + "bbox": [ + 308, + 399, + 547, + 453 + ], + "type": "text", + "content": "[20] Prannay Khosla, Piotr Teterwak, Chen Wang, Aaron Sarna, Yonglong Tian, Phillip Isola, Aaron Maschinot, Ce Liu, and Dilip Krishnan. Supervised contrastive learning. Advances in Neural Information Processing Systems, 33:18661-18673, 2020. 5" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 456, + 547, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 456, + 547, + 498 + ], + "spans": [ + { + "bbox": [ + 308, + 456, + 547, + 498 + ], + "type": "text", + "content": "[21] Wonjae Kim, Bokyung Son, and Ildoo Kim. Vilt: Vision-and-language transformer without convolution or region supervision. In International Conference on Machine Learning, pages 5583-5594. PMLR, 2021. 1, 2, 4" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 501, + 547, + 532 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 501, + 547, + 532 + ], + "spans": [ + { + "bbox": [ + 308, + 501, + 547, + 532 + ], + "type": "text", + "content": "[22] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. 6" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 535, + 547, + 589 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 535, + 547, + 589 + ], + "spans": [ + { + "bbox": [ + 308, + 535, + 547, + 589 + ], + "type": "text", + "content": "[23] Qiuqiang Kong, Yin Cao, Turab Iqbal, Yuxuan Wang, Wenwu Wang, and Mark D Plumbley. Panns: Large-scale pretrained audio neural networks for audio pattern recognition. IEEE/ACM Transactions on Audio, Speech, and Language Processing, 28:2880-2894, 2020. 3" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 591, + 547, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 591, + 547, + 644 + ], + "spans": [ + { + "bbox": [ + 308, + 591, + 547, + 644 + ], + "type": "text", + "content": "[24] Shengjie Luo, Shanda Li, Tianle Cai, Di He, Dinglan Peng, Shuxin Zheng, Guolin Ke, Liwei Wang, and Tie-Yan Liu. Stable, fast and accurate: Kernelized attention with relative positional encoding. Advances in Neural Information Processing Systems, 34:22795-22807, 2021. 2" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 647, + 547, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 647, + 547, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 647, + 547, + 689 + ], + "type": "text", + "content": "[25] Rada Mihalcea and Paul Tarau. Textrank: Bringing order into text. In Proceedings of the 2004 conference on empirical methods in natural language processing, pages 404-411, 2004. 7" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 691, + 547, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 691, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 691, + 547, + 713 + ], + "type": "text", + "content": "[26] Paramita Mirza, Mostafa Abouhamra, and Gerhard Weikum. Alignnarr: Aligning narratives on movies. In The 59th Annual" + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "text", + "content": "23339" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "type": "text", + "content": "Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing, pages 427-433. ACL, 2021. 3, 5" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 108, + 288, + 152 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 108, + 288, + 152 + ], + "spans": [ + { + "bbox": [ + 48, + 108, + 288, + 152 + ], + "type": "text", + "content": "[27] Jonghwan Mun, Minchul Shin, Gunsoo Han, Sangho Lee, Seongsu Ha, Joonseok Lee, and Eun-Sol Kim. Boundary-aware self-supervised learning for video scene segmentation. arXiv preprint arXiv:2201.05277, 2022. 2, 3, 4, 6, 7, 8" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 154, + 288, + 197 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 154, + 288, + 197 + ], + "spans": [ + { + "bbox": [ + 48, + 154, + 288, + 197 + ], + "type": "text", + "content": "[28] Arsha Nagrani, Shan Yang, Anurag Arnab, Aren Jansen, Cordelia Schmid, and Chen Sun. Attention bottlenecks for multimodal fusion. Advances in Neural Information Processing Systems, 34:14200-14213, 2021. 2, 3, 4" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 199, + 288, + 254 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 199, + 288, + 254 + ], + "spans": [ + { + "bbox": [ + 48, + 199, + 288, + 254 + ], + "type": "text", + "content": "[29] Pinelopi Papalampidi, Frank Keller, Lea Frermann, and Mirella Lapata. Screenplay summarization using latent narrative structure. In Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics, pages 1920-1933, 2020. 6, 7" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 256, + 288, + 289 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 256, + 288, + 289 + ], + "spans": [ + { + "bbox": [ + 48, + 256, + 288, + 289 + ], + "type": "text", + "content": "[30] Pinelopi Papalampidi, Frank Keller, and Mirella Lapata. Movie plot analysis via turning point identification. arXiv preprint arXiv:1908.10328, 2019. 1, 2, 3, 6, 7, 8" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 291, + 288, + 323 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 291, + 288, + 323 + ], + "spans": [ + { + "bbox": [ + 48, + 291, + 288, + 323 + ], + "type": "text", + "content": "[31] Pinelopi Papalampidi, Frank Keller, and Mirella Lapata. Film trailer generation via task decomposition. arXiv preprint arXiv:2111.08774, 2021. 2, 5" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 326, + 288, + 369 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 326, + 288, + 369 + ], + "spans": [ + { + "bbox": [ + 48, + 326, + 288, + 369 + ], + "type": "text", + "content": "[32] Pinelopi Papalampidi, Frank Keller, and Mirella Lapata. Movie summarization via sparse graph construction. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 13631-13639, 2021. 1, 2, 4, 5, 6, 7, 8" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 372, + 288, + 394 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 372, + 288, + 394 + ], + "spans": [ + { + "bbox": [ + 48, + 372, + 288, + 394 + ], + "type": "text", + "content": "[33] Patrice Pavis. Dictionary of the theatre: Terms, concepts, and analysis. University of Toronto Press, 1998. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 396, + 288, + 461 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 396, + 288, + 461 + ], + "spans": [ + { + "bbox": [ + 48, + 396, + 288, + 461 + ], + "type": "text", + "content": "[34] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning, pages 8748-8763. PMLR, 2021. 3, 5" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 464, + 288, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 464, + 288, + 529 + ], + "spans": [ + { + "bbox": [ + 48, + 464, + 288, + 529 + ], + "type": "text", + "content": "[35] Anyi Rao, Linning Xu, Yu Xiong, Guodong Xu, Qingqiu Huang, Bolei Zhou, and Dahua Lin. A local-to-global approach to multi-modal movie scene segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10146-10155, 2020. 1, 2, 5, 6, 7, 8" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 532, + 288, + 563 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 532, + 288, + 563 + ], + "spans": [ + { + "bbox": [ + 48, + 532, + 288, + 563 + ], + "type": "text", + "content": "[36] Zeeshan Rasheed and Mubarak Shah. Detection and representation of scenes in videos. IEEE transactions on Multimedia, 7(6):1097-1105, 2005. 6" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 567, + 288, + 609 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 567, + 288, + 609 + ], + "spans": [ + { + "bbox": [ + 48, + 567, + 288, + 609 + ], + "type": "text", + "content": "[37] Daniel Rotman, Dror Porat, and Gal Ashour. Optimal sequential grouping for robust video scene detection using multiple modalities. International Journal of Semantic Computing, 11(02):193-208, 2017. 6" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 613, + 288, + 677 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 613, + 288, + 677 + ], + "spans": [ + { + "bbox": [ + 48, + 613, + 288, + 677 + ], + "type": "text", + "content": "[38] Peter Shaw, Jakob Uszkoreit, and Ashish Vaswani. Self-attention with relative position representations. In Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 2 (Short Papers), pages 464–468, 2018. 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 680, + 288, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 680, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 680, + 288, + 713 + ], + "type": "text", + "content": "[39] Tomáš Souček and Jakub Lokoc. Transnet v2: an effective deep network architecture for fast shot transition detection. arXiv preprint arXiv:2008.04838, 2020. 1, 3" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 642 + ], + "type": "list", + "angle": 0, + "index": 26, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "text", + "content": "[40] Jianlin Su, Yu Lu, Shengfeng Pan, Bo Wen, and Yunfeng Liu. Roformer: Enhanced transformer with rotary position embedding. arXiv preprint arXiv:2104.09864, 2021. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 108, + 547, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 108, + 547, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 108, + 547, + 150 + ], + "type": "text", + "content": "[41] Makarand Tapaswi, Martin Bauml, and Rainer Stiefelhagen. Storygraphs: visualizing character interactions as a timeline. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 827-834, 2014. 6" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 152, + 547, + 195 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 547, + 195 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 547, + 195 + ], + "type": "text", + "content": "[42] Makarand Tapaswi, Martin Bäuml, and Rainer Stiefelhagen. Aligning plot synopses to videos for story-based retrieval. International Journal of Multimedia Information Retrieval, 4(1):3-16, 2015. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 197, + 547, + 240 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 197, + 547, + 240 + ], + "spans": [ + { + "bbox": [ + 307, + 197, + 547, + 240 + ], + "type": "text", + "content": "[43] Makarand Tapaswi, Martin Bauml, and Rainer Stiefelhagen. Book2movie: Aligning video scenes with book chapters. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1827-1835, 2015. 3" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 241, + 547, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 241, + 547, + 285 + ], + "spans": [ + { + "bbox": [ + 307, + 241, + 547, + 285 + ], + "type": "text", + "content": "[44] Yikai Wang, Wenbing Huang, Fuchun Sun, Tingyang Xu, Yu Rong, and Junzhou Huang. Deep multimodal fusion by channel exchanging. Advances in Neural Information Processing Systems, 33:4835-4845, 2020. 2, 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 286, + 547, + 351 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 286, + 547, + 351 + ], + "spans": [ + { + "bbox": [ + 308, + 286, + 547, + 351 + ], + "type": "text", + "content": "[45] Haoqian Wu, Keyu Chen, Yanan Luo, Ruizhi Qiao, Bo Ren, Haozhe Liu, Weicheng Xie, and Linlin Shen. Scene consistency representation learning for video scene segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14021-14030, 2022. 2, 4, 5, 6, 8" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 353, + 547, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 353, + 547, + 407 + ], + "spans": [ + { + "bbox": [ + 308, + 353, + 547, + 407 + ], + "type": "text", + "content": "[46] Saining Xie, Ross Girshick, Piotr Dólar, Zhuowen Tu, and Kaiming He. Aggregated residual transformations for deep neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1492-1500, 2017. 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 409, + 547, + 462 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 409, + 547, + 462 + ], + "spans": [ + { + "bbox": [ + 308, + 409, + 547, + 462 + ], + "type": "text", + "content": "[47] Yu Xiong, Qingquiu Huang, Lingfeng Guo, Hang Zhou, Bolei Zhou, and Dahua Lin. A graph-based framework to bridge movies and synopses. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4592-4601, 2019. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 464, + 547, + 520 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 464, + 547, + 520 + ], + "spans": [ + { + "bbox": [ + 308, + 464, + 547, + 520 + ], + "type": "text", + "content": "[48] Ning Zhang, Manohar Paluri, Yaniv Taigman, Rob Fergus, and Lubomir Bourdev. Beyond frontal faces: Improving person recognition using multiple cues. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4804-4813, 2015. 6" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 520, + 547, + 597 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 520, + 547, + 597 + ], + "spans": [ + { + "bbox": [ + 308, + 520, + 547, + 597 + ], + "type": "text", + "content": "[49] Chao Zhao, Wenlin Yao, Dian Yu, Kaiqiang Song, Dong Yu, and Jianshu Chen. Learning-by-narrating: Narrative pretraining for zero-shot dialogue comprehension. In Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers), pages 212-218, Dublin, Ireland, May 2022. Association for Computational Linguistics. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 599, + 547, + 642 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 599, + 547, + 642 + ], + "spans": [ + { + "bbox": [ + 308, + 599, + 547, + 642 + ], + "type": "text", + "content": "[50] Bolei Zhou, Agata Lapedriza, Aditya Khosla, Aude Oliva, and Antonio Torralba. Places: A 10 million image database for scene recognition. IEEE transactions on pattern analysis and machine intelligence, 40(6):1452-1464, 2017. 3, 6" + } + ] + } + ], + "index": 25 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 749, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 318, + 757 + ], + "type": "text", + "content": "23340" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/913ed268-24e1-487c-b23b-995e3fca2c86_content_list.json b/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/913ed268-24e1-487c-b23b-995e3fca2c86_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..970c7a714e5491f2bb115f40e5d861f7a7d0c4b2 --- /dev/null +++ b/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/913ed268-24e1-487c-b23b-995e3fca2c86_content_list.json @@ -0,0 +1,1527 @@ +[ + { + "type": "text", + "text": "MGMAE: Motion Guided Masking for Video Masked Autoencoding", + "text_level": 1, + "bbox": [ + 140, + 130, + 828, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Bingkun Huang $^{1,2}$ Zhiyu Zhao $^{1,2}$ Guozhen Zhang $^{1}$ Yu Qiao $^{2}$ Limin Wang $^{1,2,\\text{图}}$ $^{1}$ State Key Laboratory for Novel Software Technology, Nanjing University $^{2}$ Shanghai AI Lab https://github.com/MCG-NJU/MGMAE", + "bbox": [ + 101, + 178, + 867, + 243 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 268, + 313, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Masked autoencoding has shown excellent performance on self-supervised video representation learning. Temporal redundancy has led to a high masking ratio and customized masking strategy in VideoMAE. In this paper, we aim to further improve the performance of video masked autoencoding by introducing a motion guided masking strategy. Our key insight is that motion is a general and unique prior in video, which should be taken into account during masked pretraining. Our motion guided masking explicitly incorporates motion information to build temporal consistent masking volume. Based on this masking volume, we can track the unmasked tokens in time and sample a set of temporal consistent cubes from videos. These temporal aligned unmasked tokens will further relieve the information leakage issue in time and encourage the MGMAE to learn more useful structure information. We implement our MGMAE with an online efficient optical flow estimator and backward masking map warping strategy. We perform experiments on the datasets of Something-Something V2 and Kinetics-400, demonstrating the superior performance of our MGMAE to the original VideoMAE. In addition, we provide the visualization analysis to illustrate that our MGMAE can sample temporal consistent cubes in a motion-adaptive manner for more effective video pre-training.", + "bbox": [ + 75, + 300, + 473, + 662 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 685, + 209, + 700 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Attention-based Transformer [38] has witnessed great success in computer vision since the introduction of Vision Transformer (ViT) [12]. It has been applied for a variety of vision tasks and obtains state-of-the-art performance, such as image classification [36, 59, 52], object detection [23, 46], semantic segmentation [49], and object tracking [8]. Thanks to this high performance, ViT models have been also applied to the video domain for action recognition [5, 1] and detection [33, 54]. However, the high capacity of Transformer often demands pre-training on a large-scale dataset to reduce the over-fitting risk of subsequent fine", + "bbox": [ + 75, + 710, + 470, + 877 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/d4dab8bfd4010748a06b3de6e48e1ee025825d8792f44d5a49846a90d466612f.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 506, + 266, + 686, + 333 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/a1f20a198bd90758e6c3ee15b54d130e39e5d2ae73f60a40e39f39d400530110.jpg", + "image_caption": [ + "(a) original video clip", + "(c) random masking", + "Figure 1: Comparison of different masking strategies. Masked autoencoding [11, 17] has been explored in video domain for self-supervised pre-training by employing different masking strategies: random masking [14] and tube masking [35]. We propose to track masking maps under the guidance of motion information (termed as motion guided masking). Our resulting MGMAE can build a more challenging and meaningful task for video pre-training." + ], + "image_footnote": [], + "bbox": [ + 504, + 354, + 683, + 421 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/ddb52fbe1b47eebe164b05caf6541ce36ee9c4a233a060042c877eb5d81fa49b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 705, + 266, + 885, + 333 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/2415c759021d623aeab12bdfef0c56a17bbfee998738cbe4ca04de3213372218.jpg", + "image_caption": [ + "(b) tube masking", + "(d) motion guided masking" + ], + "image_footnote": [], + "bbox": [ + 702, + 353, + 890, + 420 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "tuning. Therefore, an effective pretraining strategy of ViT is particularly important for obtaining excellent performance in the video domain due to the smaller video dataset.", + "bbox": [ + 496, + 582, + 890, + 627 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The early video transformers [1, 5] often rely on the pre-training of image-based transformer derived from the large-scale image dataset [10]. This pre-training scheme makes the learnt video model to be naturally biased by image-based ViTs. Recently, masked autoencoding (MAE) [35, 14, 41] has been explored for pre-training video transformer on the video dataset due to its simplicity and promising result in image domain [17]. However, unlike the image, video data is equipped with an extra time dimension and exhibits the unique property of temporal redundancy and correlation. This property requires some customized designs on video masked autoencoder compared with image-based MAE. For example, VideoMAE and MAE-ST both propose to use an extremely high masking ratio in video masked autoencoder pre-training to improve its performance. In addition, VideoMAE devises a tube masking strategy of dropping tokens at the same position across frames to further relieve the information leakage in time. This tube masking", + "bbox": [ + 496, + 628, + 893, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "$\\boxtimes$ : Corresponding author (lmwang@nju.edu.cn).", + "bbox": [ + 99, + 887, + 359, + 900 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "13493", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "approach, though straightforward, makes the assumption of no or small motion occurring between adjacent frames. Such an assumption might be not true for some scenarios with high-speed motion.", + "bbox": [ + 78, + 90, + 467, + 150 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Based on the above analysis, in this paper, we aim to propose a new masking strategy for improving video masked autoencoder pre-training, by explicitly using motion information to reduce information leakage in time. Specifically, we devise the Motion Guided Masking in the video masked encoder processing and the resulted masked autoencoder is termed as MGMAE. Motion is general prior information contained by video. The optical flow representation explicitly encodes the movement of each pixel from the current frame to the next one. We propose to use this optical flow to align masking maps between adjacent frames to build consistent masking volumes across time. The consistent masking volumes enable to build a more challenging reconstruction task by enforcing only a small set of cube tracks visible to the encoder. Hopefully, this motion guided masking can further relieve the risk of information leakage in time and encourage learning more meaningful visual representations.", + "bbox": [ + 78, + 159, + 467, + 415 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "More specifically, we use an online and lightweight optical flow estimator (RAFT [34]) to capture motion information, which could be seamlessly integrated into the existing VideoMAE framework. To build the temporally consistent masking volume, we first randomly generate an initial masking map at the base frame. Then, we use the estimated optical flow to warp the initial masking map to adjacent frames. With multiple warping operations, we build the temporal consistent masking volume for all frames in the video. Finally, based on this masking volume, we sample a set of visible tokens to MAE encoders with top-k selection based on a frame-wise manner. The same autoencoding process with the original VideoMAE is applied to these sampled tokens for video pretraining. With this simple motion guided masking, we are able to further increase the difficulty of video pre-training task and thus lead to a better pre-trained model for subsequent fine-tuning.", + "bbox": [ + 78, + 424, + 467, + 679 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We mainly verify the effectiveness of the proposed MGMAE on the datasets of Something-Something V2 [16] and Kinetics-400 [20] by comparing them with the original tube masking in VideoMAE. The results demonstrate that MGMAE pre-training can result in more powerful video foundation models with higher fine-tuning accuracy on the downstream tasks. In particular, on the motion-centric benchmark of Something-Something, the improvement of MGMAE is more evident, implying that our motion guided masking is adaptive to motion variations and can better capture temporal structure information for pre-training. We hope our findings can inspire some specific and unique designs in video masked autoencoding with respect to image counterparts.", + "bbox": [ + 78, + 689, + 467, + 898 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 504, + 90, + 638, + 104 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Masked Visual Modeling. Masked autoencoder is a long-standing unsupervised learning framework in computer vision. The early work presented general form of denoising autoencoder [40, 39] for learning representation by reconstructing the clean signal from the noisy inputs. The other work [27] also treated masking modeling as inpainting missing regions from the surrounding context by using convolutions. Inspired by the great success of masked language modeling [11], some works also attempted to apply this pretraining paradigm to the vision domain for self-supervised pre-training. For example, iGPT [7] followed the GPT work [30] in NLP and processed a sequence of pixels for casual prediction of the next pixels. The original ViT [12] used the masked token prediction as a self-supervised training step on large-scale image datasets but failed to obtain impressive results. Recently, several interesting works have obtained a great breakthrough in self-supervised image pre-training by using masked image modeling, such as BEiT [3], SimMIM [50], and MAE [17]. BEiT [3] directly followed the BERT framework and proposed to predict the discrete token label for masked patches, by requiring an explicit tokenizer to build the token dictionary. SimMIM [50] and MAE [17] shared the same design of directly predicting the pixels of masked patches without any tokenizer design. Furthermore, MAE [17] devised an asymmetric encoder-decoder architecture to speed up the masked image pre-training.", + "bbox": [ + 503, + 114, + 890, + 506 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Since the great success in masked image modeling, some works have tried to extend this new pre-training paradigm to the video domain for self-supervised video pre-training. BEVT [45] and VIMPAC [32] proposed to learn video representation by predicting discrete visual tokens in a similar way to BEiT. However, their performance improvement in video action recognition is limited. MaskFeat [48] used the HOG features [9] as the reconstructed targets of masked patches and achieved excellent performance on the video recognition with a multi-scale vision transformer. VideoMAE [35] and MAE-ST [14] extended the image MAE to the video domain for representation learning with vanilla vision transformer. They both proposed to use an extremely high masking ratio to deal with video data redundancy. Meanwhile, VideoMAE [35] used the tube masking to further increase the difficulty of reconstruction. Several works building upon VideoMAE have emerged. For instance, MAR [29] reduced both training and inference costs by introducing running cell masking. Meanwhile, VideoMAE V2 [41] proposes a dual masking strategy to decrease pre-training overhead, and by expanding both the model size and dataset, it further explores the scalability of VideoMAE. Our proposed motion guided masking aims to improve the performance of VideoMAE by building a more challenging masking and reconstruction task. In contrast to the original VideoMAE, our MGMAE explicitly use the optical flow to align the masking maps", + "bbox": [ + 503, + 508, + 890, + 898 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "13494", + "bbox": [ + 480, + 946, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "across frames and generate the temporal consistent masking volume to sample a set of visible tokens.", + "bbox": [ + 76, + 90, + 468, + 121 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Motion Guided Modeling. Motion information, such as optical flow, is a general prior information in videos and represents the unique characteristics distinct from images. Optical flow has been widely introduced to provide a strong prior in both low-level and high-level vision tasks on video. For low-level video tasks, the motion is often used to align the information of auxiliary frames to the corresponding region of the target frame. In the case of video super-resolution, BasicVSR++ [6] uses optical flow to enhance the appearance of low-resolution frames by transferring features from neighbor frames. For video inpainting, Zhang et al. [56] exploits the motion difference extracted by optical flows to instruct the attention retrieval in transformer for high-fidelity video inpainting. As for video frame interpolation, mainstream methods leverage optical flow directly on the image to synthesize the intermediate frame, such as DAIN [4] and RIFE [18], while Zhang et al. [55] introduces a unified operation utilizing inter-frame attention to concurrently extract motion and appearance information, and blends a hybrid CNN and Transformer design for efficiency and fine-grained detail preservation. For high-level video tasks, the optical flow is directly used as a data modality as network input for action recognition [44, 31]. TDD [42] utilized motion trajectories to pool deep convolutional features for action recognition. Trajectory Convolution [57] incorporated the motion information into temporal convolutional kernel design. MSNet [21] proposes a pluggable MotionSqueeze module to generate motion information across frames. VideoMS [19] generates mask maps by calculating the feature difference after patch embedding, making an attempt at dynamically adjusting mask positions. AdaMAE [2] introduces an end-to-end trainable adaptive masking strategy for MAEs, leveraging an auxiliary sampling network to prioritize tokens from high spatiotemporal information regions. Yang et al. [51] leverage hierarchical motion information to improve the extracted video features. MotionFormer [28] employed the trajectory for attention computation in the video transformer. TEA [22] and TDN [43] used RGB difference to approximate the motion information and incorporate this information into the video CNN backbone design. MGSampler [58] explored the motion information to select a subset of representative frames for efficient video action recognition. Our MGMAE shares the same spirit with these motion guided modeling works. We focus on employing motion information as a cue to generate masking maps for masked video pre-training.", + "bbox": [ + 76, + 138, + 472, + 834 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Method", + "text_level": 1, + "bbox": [ + 76, + 844, + 168, + 859 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this section, we first revisit the pre-training paradigm of VideoMAE to well introduce our MGMAE in Sec. 3.1.", + "bbox": [ + 76, + 869, + 470, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Then we present the details of motion guided masking map generation in Sec. 3.2. Finally, we describe the MGMAE pretraining under temporal consistent masking maps in Sec. 3.3.", + "bbox": [ + 498, + 90, + 893, + 137 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. VideoMAE revisited", + "text_level": 1, + "bbox": [ + 498, + 148, + 692, + 164 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "VideoMAE is a simple masked video autoencoder with an asymmetric encoder-decoder architecture with an extra cube embedding to handle the input sampled frames. Next, we briefly revisit its implementation detail.", + "bbox": [ + 498, + 172, + 893, + 234 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Cube Embedding. VideoMAE divides the input video clip $\\mathbf{I}$ of size $T\\times 3\\times H\\times W$ into non-overlapping cubes $\\mathbf{C} = \\{\\mathbf{C}_i\\mid \\mathbf{C}_i\\in \\mathbb{R}^{2\\times 16\\times 16\\times 3}\\}_{i = 1}^N$ , where $N = \\frac{T}{2}\\times \\frac{H}{16}\\times \\frac{W}{16}$ is the number of cubes. Then apply cube embedding on the cubes to produce the video tokens $\\mathbf{T} = \\{\\mathbf{T}_i\\mid \\mathbf{T}_i\\in \\mathbb{R}^D\\}_{i = 1}^N$ , where $T_{i}$ represents the cube embedding with positional encoding, and $D$ is the channel.", + "bbox": [ + 498, + 258, + 893, + 372 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Masking Strategy. VideoMAE uses the tube masking strategy with an extremely high masking ratio $\\rho$ (i.e. $90\\%$ ), which samples the same spatial positions across all frames of the input video clip. Specifically, VideoMAE first generate a $\\frac{H}{16} \\times \\frac{W}{16}$ binary mask map $\\mathbf{M}'$ where 0 represents unmasked and 1 represents masked. Then it replicates it in temporal dimension and then flattens it to produce the token-level mask map $\\mathbf{M}$ whose size is $N$ for the input video clip. We denote $\\mathbb{M}$ as the masking maps.", + "bbox": [ + 498, + 397, + 893, + 534 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Encoder. The encoder is a vanilla ViT with joint space-time attention [5]. For computation efficiency, only the unmasked visible tokens $\\mathbf{T}^v = \\{\\mathbf{T}_i\\}_{i\\notin \\mathbb{M}}$ added with the fixed positional embedding are fed into the encoder to obtain the latent features $\\mathbf{Z}$ of size $N_v\\times D$ , where $N_{v} = \\lfloor (1 - \\rho)N\\rfloor$ is the total number of the unmasked visible tokens.", + "bbox": [ + 498, + 558, + 893, + 648 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Decoder. The decoder is a narrower and shallower ViT than the encoder. It takes the concatenated token sequences as input, which is formed by the concatenation between the latent features $\\mathbf{Z}$ and the learnable [MASK] tokens with the fixed position embedding added, to reconstruct the normalized video cubes $\\hat{\\mathbf{C}} = \\left\\{\\hat{\\mathbf{C}}_i \\mid \\hat{\\mathbf{C}}_i \\in \\mathbb{R}^{2 \\times 16 \\times 16 \\times 3}\\right\\}_{i=1}^N$ .", + "bbox": [ + 498, + 674, + 893, + 779 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Loss. The pre-training object is to minimize the Mean Square Error Loss between the normalized $\\mathbf{C}$ and $\\hat{\\mathbf{C}}$ on the masked positions, i.e. $\\frac{1}{\\rho N} \\sum_{i \\in \\mathbb{M}} \\left| \\hat{\\mathbf{C}}_i - \\mathrm{norm}(\\mathbf{C}_i) \\right|^2$ .", + "bbox": [ + 498, + 800, + 890, + 854 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "After the pre-training, the encoder will be used as the backbone network to fine-tune on the downstream tasks to obtain a specialized model.", + "bbox": [ + 498, + 854, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "13495", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/3cdb054ac6de8fe38e81bf3be96d5041084f8f4dba66d980c38d9ebe40945d87.jpg", + "image_caption": [ + "Figure 2: Pipeline of MGMAE. Our MGMAE follows the simple pipeline of masking and reconstruction for video self-supervised pre-training. Our core design is to propose a motion guided masking strategy to generate temporal consistent masking volume. With this masking volume, we track the visible cubes and attain temporal consistency for masking maps. As a result, we can build a more challenging reconstruction task and encourage extracting more effective representations during masked self-supervised pretraining." + ], + "image_footnote": [], + "bbox": [ + 106, + 95, + 861, + 383 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Motion Guided Masking Map", + "text_level": 1, + "bbox": [ + 76, + 505, + 344, + 523 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Time is a unique characteristic of video and has different properties with the space dimension. When devising masked video autoencoder, we need to carefully take this extra time dimension into account and come up with a customized design. Information leakage in time is an important issue in masked video pre-training. When information leakage occurs, the model can easily reconstruct the masked cubes based on the visible tokens of adjacent frames. In this case, it will greatly reduce the difficulty of the reconstruction task and lead to a pre-trained model with poor fine-tuning performance. A trivial solution to information leakage is to increase the masking ratio. VideoMAE [35] and MAE-ST [14] increase the masking ratio to $90\\%$ to greatly increase the difficulty of reconstruction. In addition, VideoMAE makes the small motion assumption and adapts the tube masking strategy, which masks the same spatial position in all frames. However, this small motion prior is not always true for motion-dominated videos. A more reasonable approach is to keep each object in the video clip visible or invisible at all times. To achieve this goal, we propose the motion guided masking strategy to replace the tube masking strategy in VideoMAE. The strategy has two procedures: we first use the optical flow as guidance to generate temporally consistent masking volumes of the input video clip", + "bbox": [ + 75, + 537, + 473, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "and then sample the unmasked visible tokens based on the temporal consistent masking volume. We will detail these two procedures in Sec. 3.2 and Sec. 3.3.", + "bbox": [ + 496, + 506, + 890, + 550 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In general, the procedure for generating the temporal consistent masking volumes has four steps as follows.", + "bbox": [ + 496, + 551, + 890, + 582 + ], + "page_idx": 3 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- Step 1: Determine the base frame $\\mathbf{I}_b$ , where $b$ is the index of the base frame.", + "- Step 2: Randomly generate a pixel-level initial mask map $\\mathbf{M}_b$ with size $H \\times W$ as the mask map of $\\mathbf{I}_b$ .", + "- Step 3: Extract the dense flows $\\mathbf{F}$ bidirectionally from the base frame $\\mathbf{I}_b$ in the input video clip $\\mathbf{I}$ .", + "- Step 4: Warp the initial masking map $\\mathbf{M}_b$ under the guidance of dense flows $\\mathbf{F}$ and progressively build the temporal consistent masking volume $\\mathbf{M}$ of size $T \\times H \\times W$ ." + ], + "bbox": [ + 517, + 594, + 890, + 773 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Determine the base frame. By default, we choose the middle frame as the base frame. In motion guided masking, we need to ensure all objects in the base frame remain consistently visible or invisible in all frames of the input clip. Note that objects may (dis)appear over time due to object or camera movement, and warping the masking map under optical flow can result in some holes due to pixels mapped", + "bbox": [ + 496, + 795, + 893, + 902 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "13496", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "out of bounds. So the choice of the base frame may have an impact on the suppression of information leakage. We ablate the choice of the base frame in Sec. 4.2 and the middle frame is the optimal choice.", + "bbox": [ + 75, + 90, + 470, + 151 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Generate the initial mask map. We initialize a pixel-level masking map for the base frame with the distribution of the Gaussian Mixture Model (GMM). We use the masking map to indicate the visible or invisible state of the cubes in the base frame. Previous masking strategies usually adapt a token-level binary initialization, i.e. either all 0 or all 1 within each token of size $2 \\times 16 \\times 16$ , which actually breaks the continuity of the object surface texture.", + "bbox": [ + 75, + 169, + 468, + 289 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Specifically, we first randomly pick $\\hat{N}_v = \\left\\lfloor (1 - \\rho) \\times \\frac{H}{16} \\times \\frac{W}{16} \\right\\rfloor$ tokens whose centers are denoted with $c = \\{\\vec{c_i} : (c_{i1}, c_{i2})\\}_i^{\\hat{N}_v}$ . Then we generate 2D Gaussian distributions $\\mathcal{N}_i(c_i, \\sigma^2)$ centered on the midpoint of each token, where $\\sigma$ is the standard deviation and taken as the cube size (16, 16). Thus we will obtain the mixed Gaussian distribution $\\mathcal{P}(c, \\sigma^2) = \\sum_{i}^{\\hat{N}_v} \\mathcal{N}_i(\\vec{c_i}, \\sigma^2)$ corresponding to the base frame. And the probability density function of the mixed Gaussian distribution is used to indicate the probability that the cube (token) is visible in the base frame.", + "bbox": [ + 76, + 289, + 470, + 450 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Extract optical flows. We use both online and offline alternative methods to extract optical flow. Online method adapts RAFT [34] (the small version) to estimate the flows of the input video clip. Offline method applies the traditional TVL1 [53] algorithm to extract the dense flows between all adjacent frames in advance. We perform the consistent crop-resize-rescale operations when reading flows. Online and offline methods achieve the similar results. More details see in Sec. 4.2.", + "bbox": [ + 75, + 468, + 468, + 602 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In practice, we only extract the flows $\\mathbf{F}$ forward and backward from the base frame $\\mathbf{I}_b$ , i.e.", + "bbox": [ + 75, + 604, + 468, + 635 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {F} = \\left\\{v _ {i \\rightarrow i + 1} \\right\\} _ {i = 1} ^ {b - 1} \\cup \\left\\{v _ {i \\rightarrow i - 1} \\right\\} _ {i = b + 1} ^ {T}, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 143, + 642, + 468, + 662 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where the flow $v_{i\\rightarrow j}$ denotes the flow from $\\mathbf{I}_i$ to $\\mathbf{I}_j$ .", + "bbox": [ + 76, + 671, + 416, + 686 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Warp masking maps with flows. We utilize the method of backward warping to generate the temporal consistent masking map of the video clip in a progressive manner. Forward warping $\\phi_F$ and backward warping $\\phi_B$ are two opposite patterns of warping. Both can be effectively employed to construct the masking volume from the initial masking map. Regrettably, forward warping suffers from hole or occlusion problems, that is, no flow vectors may pass to a certain pixel, or there may be multiple flow vectors passing to the same pixel. In contrast, backward warping maps the pixels of a given map one by one to individual locations. It's noteworthy that while backward warping doesn't escape from the issue of holes caused by mapping out of bounds, these holes are", + "bbox": [ + 75, + 704, + 470, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "usually fewer than in forward warping and tend to occur at the boundaries of the map, thus causing less damage to the information distribution. For the holes caused by backward warping, we fill them with the values of $\\mathbf{M}_b$ at the same position to simulate the tube masking strategy.", + "bbox": [ + 496, + 90, + 890, + 167 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Formally, given the flows $\\mathbf{F}$ and the base frame masking volume $\\mathbf{M}_b$ , the mask map $\\mathbf{M}_i$ of $\\mathbf{I}_i$ can be constructed as", + "bbox": [ + 498, + 167, + 890, + 196 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {M} _ {i} = \\left\\{\\begin{array}{l l}\\phi_ {B} \\left(\\mathbf {M} _ {i + 1}, v _ {i \\rightarrow i + 1}\\right),&1 \\leq i < b\\\\\\mathbf {M} _ {b},&i = b\\\\\\phi_ {B} \\left(\\mathbf {M} _ {i - 1}, v _ {i \\rightarrow i - 1}\\right),&b < i \\leq T\\end{array}. \\right. \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 547, + 207, + 890, + 262 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Subsequently, the entire masking volume $\\mathbf{M} = \\{\\mathbf{M}_i\\}_{i=1}^T$ of the video clip $\\mathbf{I}$ can be constructed by backward warping the flows $\\mathbf{F}$ bidirectionally, originating from the base frame mask map $\\mathbf{M}_b$ .", + "bbox": [ + 496, + 273, + 890, + 335 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.3. Motion Guided MAE", + "text_level": 1, + "bbox": [ + 500, + 344, + 699, + 358 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We build our MGMAE based on the above motion guided masking map. The temporal consistent masking volume indicates the probability that the corresponding position in the adjacent frame is visible under optical flow tracking. In order to suppress information leakage as much as possible, we sample the video tokens with the highest visible probability along the temporal dimension. Specifically, we first perform average pooling with kernel size $2 \\times 16 \\times 16$ on the masking volume $\\mathbf{M}$ to obtain the token-level masking volume $\\mathbf{M}'$ of size $\\frac{T}{2} \\times \\frac{H}{16} \\times \\frac{W}{16}$ . Then we pick the top- $\\hat{N}_v$ locations of each mask map of size $\\frac{H}{16} \\times \\frac{W}{16}$ along the temporal dimension and thus sample $N_v$ corresponding video tokens as the unmasked visible tokens.", + "bbox": [ + 496, + 367, + 893, + 564 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "These sampled tokens according to our temporal consistent masking volume are fed into the asymmetric encoder-decoder for autoencoding based pre-training. The resulted pre-training framework is called Motion Guided Masked Autoencoder (MGMAE). The pre-trained model by our MGMAE is applied in the same way with the original Video-MAE for fine-tuning the downstream tasks.", + "bbox": [ + 496, + 565, + 893, + 671 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Discussion. Previous works [35, 14] extended MAE to the video domain. They opted for the random (agnostic) masking and tube (space-only) masking strategies, respectively. Random masking introduces no explicit inductive bias about the video's space and time dimension. It aims to present a unified feature representation learning framework with minimal domain knowledge. We argue that although this idea is simple, time is inherently a distinctive dimension from space. By recognizing this, we could better leverage this prior information for enhanced video masked autoencoding. Tube masking assumes that a large area of the frame contains no or small motion, and thus masking the same position across frames could greatly reduce the information leakage risk. However, for motion-dominated video datasets such as", + "bbox": [ + 496, + 688, + 893, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "13497", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Something-Something, this assumption will no longer hold true. Our proposed motion guided masking offers a more general and conceptually simple solution to take temporal correlation into account. It could be viewed as an adaptive video masking strategy and create more challenging yet meaningful tasks in video pre-training.", + "bbox": [ + 75, + 90, + 470, + 183 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 196, + 209, + 214 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Dataset", + "text_level": 1, + "bbox": [ + 76, + 223, + 171, + 238 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Following the original VideoMAE, we evaluate our MGMAE on Kinetics-400 (K400) [20] and Something-Something V2 (SSV2) [16]. K400 contains about 240k training videos and 20k validation videos from YouTube and the actions in K400 are usually coupled with specific objects or scenes, such as brushing teeth and playing piano. While SSV2 contains about 169k training videos and 25k validation videos, and the categories in SSV2 only care about specific motion patterns (e.g. push, pull). We first pre-train the video transformer with our MGMAE on the corresponding dataset for self-supervised representation learning. Then, we report the fine-tuning performance of pre-trained models on the target datasets for action recognition. In our MGMAE pretraining, we generally follow the setting and implementation of the original VideoMAE [35]. We use the RAFT [34] to extract optical flow due to its efficiency and accuracy in our MGMAE pre-training. The implementation details on our MGMAE could found in the appendix.", + "bbox": [ + 75, + 246, + 473, + 518 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Ablation Studies", + "text_level": 1, + "bbox": [ + 76, + 530, + 241, + 545 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this subsection, we conduct in-depth ablation experiments on the choice in each step of our motion guided masking strategy. We pre-train the ViT-base model 800 epochs on the SSV2 dataset with 16 80G-A100 GPUs, and then fine-tune the encoder on the SSV2 dataset for action recognition. All models share the same training schedule and report the 2 clips $\\times 3$ crops accuracy.", + "bbox": [ + 75, + 554, + 470, + 660 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Choice of the base frame. In this study, we investigate the influence of base frame selection for initial masking generation process. We compare the middle frame as the based frame with either the first or a random frame, and the result is shown in Tab. 1a. It implies the middle frame is the best.", + "bbox": [ + 75, + 681, + 468, + 772 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Warping method with optical flow. We compare two kinds of warping methods to align masking maps across frames as explained in Sec. 3.2. As previously mentioned above, the forward warping often leads to more severe occlusion and hole problems in the masking warping process. On the contrary, backward warping can effectively relieve this issue and ensure a more smooth masking warping. The", + "bbox": [ + 75, + 794, + 470, + 902 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "result in Tab. 1b demonstrates that back warping contributes to better performance.", + "bbox": [ + 498, + 90, + 890, + 121 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Sampling strategy of top-k visible tokens. We examine and compare the two sampling strategies to select the visible tokens based on our temporal consistent masking volume. Frame-level strategy samples the top-k locations for each frame independently, while clip-level strategy samples the top-k locations for the entire video jointly. As in Tab. 1c, the frame-level top-k sampling strategy achieves slightly better performance.", + "bbox": [ + 496, + 142, + 893, + 263 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Masking initialization at the base frame. We ablate the choice of generating the initial masking at the base frame as shown in Tab. 1d. The token-level initialization method divides the mask map into $\\frac{H}{16} \\times \\frac{W}{16}$ tokens of size $16 \\times 16$ , and randomly sets $90\\%$ tokens to 0 (representing masked) and $10\\%$ tokens to 1 (representing unmasked). The pixel-level initialization method randomly sets $90\\%$ pixels to 0 and $10\\%$ pixels to 1. The initialization process of the mixed Gaussian method has been detailed in Sec. 3.2. The result demonstrates that the mixed Gaussian initialization method works the best.", + "bbox": [ + 496, + 284, + 893, + 450 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Hole filling method. We investigate the various methods to handle the holes problem brought by the mapping out of bound in backward warping in Tab. 1e. To determine the real holes caused by warping, we set the 0 in the initial mask map to value $1e - 8$ , and then the locations equal to 0 in new mask maps are treated as the holes. We experiment with 5 methods to fill the holes: Invisible method fills all holes with 0, while Visible method fills all holes with 1. Random method randomly fills the holes to 0 with probability of masking ratio $\\rho$ and to 1 with probability of $1 - \\rho$ . Previous map method fills holes using the values from the same spatial positions as the last generated mask map. Conversely, Tube method fills the holes with the value from the corresponding positions of the initial mask map, aligning with tube masking principles. We see that the tube method performs the best among all the methods.", + "bbox": [ + 496, + 470, + 893, + 714 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Method of optical flow estimation. We evaluate the effect of different methods of optical flow estimation as shown in Tab. 1f. For the offline method, we use the TVL1 algorithm to extract optical flows in advance and it achieve a comparable accuracy to the online RAFT optical flow. Although VideoMAE is 1.3 times faster to train than MGMAE with RAFT-small (set to 6 testing iterations) to estimate flows, MGMAE has a clear advantage in terms of performance and reducing the risk of overfitting. We find that the offline method is not much faster than the online method because IO (reading optical flow from disk) will be a bottleneck to", + "bbox": [ + 496, + 734, + 895, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "13498", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/6cad87dbcb6507cb62fd79e9aa704045d969ada48ffea97aaa97660e9bfa935c.jpg", + "table_caption": [], + "table_footnote": [ + "(a) Base frame selection. We perform ablation study to select the base frame as the first, random or the middle frame." + ], + "table_body": "
caseAcc@1Acc@5
first frame70.592.7
random frame70.692.9
middle frame71.093.1
", + "bbox": [ + 81, + 88, + 315, + 147 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/e139dcd059024703e4b1c7da324c0330bd051464103dde11347468da5145bb93.jpg", + "table_caption": [], + "table_footnote": [ + "(d) Masking initialization. We compare three methods to generate the masking map in the base frame. Two binary random methods and one mixed Gaussian method." + ], + "table_body": "
caseAcc@1Acc@5
token rand.70.993.0
pixel rand.70.893.0
mixed Gauss71.093.1
", + "bbox": [ + 81, + 215, + 313, + 273 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/5eb223198a89e329f2eb5b4107c77f5d530482ebb67804f74e8870d7b13e46c1.jpg", + "table_caption": [], + "table_footnote": [ + "(b) Warping method. We choose forward or backward warping method for aligning masking maps." + ], + "table_body": "
caseAcc@1Acc@5
forward70.592.9
backward71.093.1
", + "bbox": [ + 349, + 95, + 584, + 138 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/326b12634022fe9b945532492ee74e23974c4422e028d4a0dc43b5123eb153ff.jpg", + "table_caption": [], + "table_footnote": [ + "(e) Hole filling. We choose some baseline choices to fill the value in the hole place caused by warping. We also use the tube filling consistent with the tube masking." + ], + "table_body": "
caseAcc@1Acc@5
random70.892.9
invisible70.792.8
visible70.893.1
previous map70.692.8
tube71.093.1
", + "bbox": [ + 367, + 202, + 596, + 286 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/42bc10fb2fcb151fa7cb116360ceaa5ad336b07b097133b0fc7fb2b7a9ecdd63.jpg", + "table_caption": [], + "table_footnote": [ + "(c) Sampling strategy. We perform a study to choose the visible token generation strategy based on motion guided masking volume." + ], + "table_body": "
caseAcc@1Acc@5
clip-level70.792.9
frame-level71.093.1
", + "bbox": [ + 645, + 95, + 880, + 138 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/bc1e4d0a6e8ec7a1d24399cdfe75c457f7fbcbc23252e79a38bb215c32f6a5e2.jpg", + "table_caption": [], + "table_footnote": [ + "(f) Method of optical flow estimation. We perform the ablation study to investigate the influence of different methods of optical flow estimation.", + "Table 1: Parts of the ablation experiments on the Something-Something V2 dataset. Our MGMAE pre-training is implemented with the 16-frame vanilla ViT-B backbone. All models are pre-trained for 800 epochs and the masking ratio is $\\rho = 90\\%$ . The inference protocol is to report the fine-tuning action recognition accuracy with 2 clips $\\times$ 3 crops. The default choice for our model is colored in gray. Although the default setting is not optimal in terms of the method of optical flow estimation, we believe that this does not affect the conclusions of the ablation experiments." + ], + "table_body": "
methodtimeAcc@1
None (VideoMAE)32 h69.6
TVL1 (offline)41 h71.2
RAFT with 6 iters43 h71.3
RAFT with 12 iters56 h71.0
", + "bbox": [ + 645, + 209, + 885, + 279 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "increase the training speed. Note that our default setting is not optimal, but the conclusions drawn in other ablation experiments should not be impacted.", + "bbox": [ + 75, + 464, + 468, + 508 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Masking ratio. The performance of MGMAE highlights the importance of improving masking strategies even at high masking rates (e.g. $90\\%$ ). However, after applying MGMAE, it remains questionable whether such high masking rates are still necessary. Indeed, as pointed out by [35, 14], blindly increasing the masking rate could potentially degrade the model performance. Our ablation study presented in Fig. 3 shows that sustaining a extremely high masking rate of over $80\\%$ is also crucial even with MGMAE. We think the video background and large objects mainly drive the need for a high masking ratio. Video backgrounds are often wide and simple. If the mask ratio is not high enough, the model can still rebuild pixels from other background parts, even if nearby frames mask similar sections. For large objects, a lower ratio might let the model use the texture from a different part of the object when another section is masked. It can also be observed that MGMAE performs optimally with $85\\%$ masking ratio, but $90\\%$ still seems to be a decent choice when considering the trade-off between training efficiency and performance.", + "bbox": [ + 75, + 530, + 472, + 834 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Exposure of masked objects. Another proposition worth considering is whether occasional exposure of masked objects help with masked video modeling pre-train. We com", + "bbox": [ + 75, + 854, + 472, + 902 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/7570868376420a105af45ff48a1d3f5c3c7f5df0ee119824359108b3acda2e9a.jpg", + "image_caption": [ + "Figure 3: The effect of masking ratio on SSV2." + ], + "image_footnote": [], + "bbox": [ + 516, + 465, + 883, + 643 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "pleted a complementary experiment. Specifically, after building the masking volume, we add Gaussian noise on the mask map of one randomly selected frame. This modification may provide a chance for masked objects to be exposed. The results showed an accuracy of $71.2\\%$ , slightly higher than the default setting of $71.0\\%$ .", + "bbox": [ + 496, + 709, + 893, + 801 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Main Results and Visualization Analysis", + "text_level": 1, + "bbox": [ + 500, + 815, + 844, + 830 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "After the detailed ablation study on the design of MGMAE, we further perform a deeper analysis by comparing it with the original VideoMAE. We also provide some intermediate visualization results to illustrate the motion guided", + "bbox": [ + 496, + 839, + 893, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "13499", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/4b26bc8dbdc7c416f6dfc1823c6c3b193513936bbfccf80e5a2a524b9b8d0957.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ModelEpochsK400SSV2
VideoMAE800 / 8000.58750.5278
MGMAE0.64620.5820
Δ loss-Δ + 0.0605Δ + 0.0542
VideoMAE1600 / 24000.58090.5122
MGMAE0.63780.5659
Δ loss-Δ + 0.0569Δ + 0.0537
", + "bbox": [ + 89, + 88, + 457, + 190 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/8341ca3baa4f7b190ec1c1867e0fa172ff68a22adc9bfdcfc8e2f5e1f4d793c9.jpg", + "table_caption": [ + "Table 2: Pre-train loss comparison of MGMAE and Video-MAE." + ], + "table_footnote": [], + "table_body": "
ModelEpochsK400SSV2
VideoMAE800 / 80080.069.6
MGMAE81.271.0
Δ Acc@1-Δ + 1.2%Δ + 1.4%
VideoMAE1600 / 240081.570.8
MGMAE81.872.3
Δ Acc@1-Δ + 0.3%Δ + 1.5%
", + "bbox": [ + 99, + 244, + 446, + 349 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 3: Accuracy comparison of MGMAE and VideoMAE.", + "bbox": [ + 76, + 359, + 467, + 375 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/905abaed5e2b8fe97517709580fbe4be655e20a936c6e87ce5cb5e75ca0ee03b.jpg", + "image_caption": [ + "Figure 4: Comparative Accuracy of MGMAE and Video-MAE by Class." + ], + "image_footnote": [], + "bbox": [ + 78, + 391, + 460, + 542 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "sampling process.", + "bbox": [ + 76, + 614, + 197, + 628 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Pre-train loss implies a more challenging task. The core design of MGMAE is to dynamically sample the positions of masked token under the guidance of optical flows and aims at increasing the difficulty of the reconstruction task. As can be seen in Tab. 2, the pre-train loss of MGMAE is always larger than that of VideoMAE by more than 0.05. This loss gap implies motion guided masking further suppresses information leakage and indeed constructs a more challenging mask-reconstruct pretext task for masked video modeling. This more difficult task would like to encourage learning more effective representations.", + "bbox": [ + 75, + 651, + 468, + 816 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Detailed breakdown of comparison between MGMAE and VideoMAE. To understand the distinct impacts of the MGMAE and VideoMAE masking strategies on video model pre-training, we delved deeper into the per-class accuracy", + "bbox": [ + 75, + 839, + 467, + 901 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/85b3fc91297b9d7f8e516955684dec58615e306756a751666d116051d95a8fd7.jpg", + "image_caption": [ + "Figure 5: Visualization of the video in SSV2 validation set. We present our motion guided mask maps and the reconstructed images. From top to bottom, the original images, the x-direction flows, the y-direction flows, the motion guided mask maps, the masked images and the reconstructed images." + ], + "image_footnote": [], + "bbox": [ + 500, + 87, + 890, + 308 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "variations between the two. Fig. 4 showcases the 29 categories with the most pronounced differences in classification accuracy between MGMAE and VideoMAE.", + "bbox": [ + 498, + 438, + 893, + 483 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "MGMAE: a more effective video representation learner. MGMAE benefits greatly from the harder task constructed by our motion guided masking strategy. On the one hand, the model has to encode the relationship between visible and invisible tokens harder, which can better guide the model training. On the other hand, the suppression of information leakage may well reduce the overfitting risk of the pretraining, and thus the model can be pre-trained much longer. As shown in Tab. 3, MGMAE consistently maintains an obvious fine-tuning performance gap with VideoMAE on the motion-centric SSV2 dataset (1.4% at 800 epochs and 1.5% at 2400 epochs) and also has some improvement on the scene-centric Kinetics-400 dataset (1.2% at 800 epochs and 0.3% at 1600 epochs).", + "bbox": [ + 498, + 507, + 893, + 718 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Visualization. We randomly seletec a video clip in SSV2 validation set and show its reconstruction example in Fig. 5. We can see that the mask map changes with object movements, which makes it more difficult for the model to reconstruct the original video.", + "bbox": [ + 498, + 742, + 893, + 816 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.4. Comparison with the state-of-the-art methods", + "text_level": 1, + "bbox": [ + 500, + 830, + 885, + 845 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We compare our approach with the previous state-of-the-art methods on the Kinetics-400 and Something-Something V2 datasets. The results are shown in Table 5 and Table 4.", + "bbox": [ + 500, + 854, + 893, + 898 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "13500", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/e350b3dc7071c9cd187a75354be9c76cf303ec32572bda79dfe5112fd66e0f52.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodBackbonePre-train dataFramesGFLOPsParamAcc@1Acc@5
TEINetEn[24]ResNet50×28+1699×10×35066.5N/A
TANetEn[26]ResNet50×2ImageNet-1K8+1699×2×35166.090.1
TDEN[43]ResNet101×28+16198×1×38869.692.2
SlowFast [15]ResNet101Kinetics-4008+32106×1×35363.187.6
MViTv1 [13]MViTv1-B64455×1×33767.790.9
TimeSformer [5]ViT-BImageNet-21K8196×1×312159.5N/A
TimeSformer [5]ViT-L645549×1×343062.4N/A
ViViT FE [1]ViT-LIN-21K+K40032995×4×3N/A65.989.9
Motionformer [28]ViT-B16370×1×310966.590.1
Motionformer [28]ViT-L321185×1×338268.191.2
Video Swin [25]Swin-B32321×1×38869.692.7
VIMPAC [32]ViT-LHowTo100M+DALLE w/o label10N/A×10×330768.1N/A
BEVT [45]Swin-BIN-1K+K400+DALLE w/o label32321×1×38870.6N/A
MAE-ST1600e [14]ViT-LKinetics-400 w/o label16597×1×330572.193.9
MaskFeat↑312 [48]MViT-LKinetics-600402828×1×321875.095.0
VideoMAE800e [35]ViT-BSSV2 w/o label16180×2×38769.692.0
VideoMAE2400e [35]ViT-B16180×2×38770.892.4
MGMAE800eViT-BSSV2 w/o label16180×2×38771.093.1
MGMAE2400eViT-B16180×2×38772.393.5
", + "bbox": [ + 161, + 87, + 803, + 345 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/3143703498d3f81fc62d4f53c7c05cc26f741e39eacbfc0ce8ec31abf9784d95.jpg", + "table_caption": [ + "Table 4: Comparison on the Something-Something V2 dataset. We only list the results obtained with the similar backbones." + ], + "table_footnote": [], + "table_body": "
MethodBackbonePre-train dataFramesGFLOPsParamAcc@1Acc@5
NL I3D [47]ResNet101ImageNet-1K128359×10×36277.393.3
TANet [26]ResNet15216242×4×35979.394.1
TDEN[43]ResNet1018+16198×10×38879.494.4
TimeSformer [5]ViT-LImageNet-21K968353×1×343080.794.7
ViViT FE [1]ViT-L1283980×1×3N/A81.793.8
Motionformer [28]ViT-L321185×10×338280.294.8
Video Swin [25]Swin-B32282×4×38882.795.5
VIMPAC [32]ViT-LHowTo100M+DALLE w/o label10N/A×10×330777.4N/A
BEVT [45]Swin-BIN-1K+DALLE w/o label32282×4×38880.6N/A
ip-CSN [37]ResNet152None32109×10×33377.892.8
SlowFast [15]R101+NL16+64234×10×36079.893.9
MViTv1 [13]MViTv1-B32170×5×13780.294.4
MAE-ST1600e [14]ViT-BKinetics-400 w/o label16180×7×38781.394.9
VideoMAE800e [35]ViT-B16180×5×38780.094.4
VideoMAE1600e [35]ViT-B16180×5×38781.595.1
MGMAE800eViT-BKinetics-400 w/o label16180×5×38781.294.9
MGMAE1600eViT-B16180×5×38781.895.0
", + "bbox": [ + 178, + 375, + 789, + 607 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 5: Comparison on the Kinetics-400 dataset. We only list the results obtained with the similar backbones.", + "bbox": [ + 112, + 616, + 854, + 631 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "For a fair comparison, we mainly list the results with similar computational cost. On the Something-Something V2 dataset, our MGMAE with ViT-B backbone achieves a performance of $72.3\\%$ when trained for 2400 epochs, which outperforms the original VideoMAE by $1.5\\%$ . On the Kinetics-400 dataset, our MGMAE obtains slightly better performance than the original VideoMAE. The small performance improvement might be ascribed to the fact that Kinetics-400 is a scene-centric action recognition benchmark and motion information is less important compared with the Something-Something dataset.", + "bbox": [ + 75, + 648, + 470, + 815 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 829, + 194, + 844 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this paper, we have proposed the Motion Guided Masked Autoencoders (MGMAE), which adapts the motion guided masking strategy to dynamically sample the", + "bbox": [ + 75, + 854, + 470, + 902 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "unmasked visible tokens under the guidance of flows, thus suppressing information leakage to build a more challenging task for masked video pre-training. Experiments have shown that MGMAE has good performance and maintains a high-performance advantage over the previous methods under fair comparison. In addition, our strategy also reduces the risk of pre-training overfitting, which allows the model to benefit from longer pre-training.", + "bbox": [ + 496, + 648, + 893, + 770 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgements. This work is supported by the National Key R&D Program of China (No. 2022ZD0160900, No.2022ZD0160100), the National Natural Science Foundation of China (No. 62076119, No. 61921006), Shanghai Committee of Science and Technology (Grant No. 21DZ1100100), and Collaborative Innovation Center of Novel Software Technology and Industrialization.", + "bbox": [ + 496, + 794, + 895, + 902 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "13501", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In IEEE/CVF International Conference on Computer Vision, 2021. 1, 9", + "[2] Wele Gedara Chaminda Bandara, Naman Patel, Ali Gholami, Mehdi Nikkhah, Motilal Agrawal, and Vishal M Patel. Adamae: Adaptive masking for efficient spatiotemporal learning with masked autoencoders. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14507-14517, 2023. 3", + "[3] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. BEit: BERT pre-training of image transformers. In International Conference on Learning Representations, 2022. 2", + "[4] Wenbo Bao, Wei-Sheng Lai, Chao Ma, Xiaoyun Zhang, Zhiyong Gao, and Ming-Hsuan Yang. Depth-aware video frame interpolation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3703-3712, 2019. 3", + "[5] Gedas Bertasius, Heng Wang, and Lorenzo Torresani. Is space-time attention all you need for video understanding? In International Conference on Machine Learning, 2021. 1, 3, 9", + "[6] Kelvin CK Chan, Shangchen Zhou, Xiangyu Xu, and Chen Change Loy. Basicvsr++: Improving video superresolution with enhanced propagation and alignment. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5972-5981, 2022. 3", + "[7] Mark Chen, Alec Radford, Rewon Child, Jeffrey Wu, Heewoo Jun, David Luan, and Ilya Sutskever. Generative pretraining from pixels. In International Conference on Machine Learning, 2020. 2", + "[8] Yutao Cui, Cheng Jiang, Limin Wang, and Gangshan Wu. Mixformer: End-to-end tracking with iterative mixed attention. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1", + "[9] Navneet Dalal and Bill Triggs. Histograms of oriented gradients for human detection. In 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR 2005), 20-26 June 2005, San Diego, CA, USA, pages 886-893. IEEE Computer Society, 2005. 2", + "[10] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In CVPR, pages 248–255. IEEE Computer Society, 2009. 1", + "[11] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In North American Chapter of the Association for Computational Linguistics, 2019. 1, 2", + "[12] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2021. 1, 2", + "[13] Haoqi Fan, Bo Xiong, Karttikeya Mangalam, Yanghao Li, Zhicheng Yan, Jitendra Malik, and Christoph Feichtenhofer. Multiscale vision transformers. In IEEE/CVF International Conference on Computer Vision, 2021. 9" + ], + "bbox": [ + 78, + 114, + 470, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[14] Christoph Feichtenhofer, Haoqi Fan, Yanghao Li, and Kaiming He. Masked autoencoders as spatiotemporal learners. In Advances in Neural Information Processing Systems, 2022. 1, 2, 4, 5, 7, 9", + "[15] Christoph Feichtenhofer, Haoqi Fan, Jitendra Malik, and Kaiming He. Slowfast networks for video recognition. In IEEE/CVF International Conference on Computer Vision, 2019. 9", + "[16] Raghav Goyal, Samira Ebrahimi Kahou, Vincent Michalski, Joanna Materzynska, Susanne Westphal, Heuna Kim, Valentin Haenel, Ingo Fründ, Peter Yianilos, Moritz Mueller-Freitag, Florian Hoppe, Christian Thurau, Ingo Bax, and Roland Memisevic. The \"something something\" video database for learning and evaluating visual common sense. In IEEE/CVF International Conference on Computer Vision, 2017. 2, 6", + "[17] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1, 2", + "[18] Zhewei Huang, Tianyuan Zhang, Wen Heng, Boxin Shi, and Shuchang Zhou. Rife: Real-time intermediate flow estimation for video frame interpolation. arXiv preprint arXiv:2011.06294, 2020.3", + "[19] Sunil Hwang, Jaehong Yoon, Youngwan Lee, and Sung Ju Hwang. Efficient video representation learning via masked video modeling with motion-centric token selection. arXiv preprint arXiv:2211.10636, 2022. 3", + "[20] Will Kay, Joao Carreira, Karen Simonyan, Brian Zhang, Chloe Hillier, Sudheendra Vijayanarasimhan, Fabio Viola, Tim Green, Trevor Back, Paul Natsev, Mustafa Suleyman, and Andrew Zisserman. The kinetics human action video dataset. arXiv preprint arXiv:1705.06950, 2017. 2, 6", + "[21] Heeseung Kwon, Manjin Kim, Suha Kwak, and Minsu Cho. Motionsqueeze: Neural motion feature learning for video understanding. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XVI 16, pages 345-362. Springer, 2020. 3", + "[22] Yan Li, Bin Ji, Xintian Shi, Jianguo Zhang, Bin Kang, and Limin Wang. TEA: temporal excitation and aggregation for action recognition. In CVPR, pages 906-915, 2020. 3", + "[23] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In IEEE/CVF International Conference on Computer Vision, 2021. 1", + "[24] Zhaoyang Liu, Donghao Luo, Yabiao Wang, Limin Wang, Ying Tai, Chengjie Wang, Jilin Li, Feiyue Huang, and Tong Lu. TEINet: Towards an efficient architecture for video recognition. In Proceedings of the AAAI Conference on Artificial Intelligence, 2020. 9", + "[25] Ze Liu, Jia Ning, Yue Cao, Yixuan Wei, Zheng Zhang, Stephen Lin, and Han Hu. Video swim transformer. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 9", + "[26] Zhaoyang Liu, Limin Wang, Wayne Wu, Chen Qian, and Tong Lu. Tam: Temporal adaptive module for video recognition." + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "13502", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "In IEEE/CVF International Conference on Computer Vision, 2021. 9", + "[27] Deepak Pathak, Philipp Krahenbuhl, Jeff Donahue, Trevor Darrell, and Alexei A. Efros. Context encoders: Feature learning by inpainting. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2016. 2", + "[28] Mandela Patrick, Dylan Campbell, Yuki M. Asano, Ishaan Misra, Florian Metze, Christoph Feichtenhofer, Andrea Vedaldi, and João F. Henriques. Keeping your eye on the ball: Trajectory attention in video transformers. In NeurIPS, pages 12493-12506, 2021. 3, 9", + "[29] Zhiwu Qing, Shiwei Zhang, Ziyuan Huang, Xiang Wang, Yuehuan Wang, Yiliang Lv, Changxin Gao, and Nong Sang. Mar: Masked autoencoders for efficient action recognition. IEEE Transactions on Multimedia, 2023. 2", + "[30] Alec Radford, Jeff Wu, Rewon Child, David Luan, Dario Amodei, and Ilya Sutskever. Language models are unsupervised multitask learners. OpenAI blog, 2019. 2", + "[31] Karen Simonyan and Andrew Zisserman. Two-stream convolutional networks for action recognition in videos. Advances in Neural Information Processing Systems, 2014. 3", + "[32] Hao Tan, Jie Lei, Thomas Wolf, and Mohit Bansal. Vimpac: Video pre-training via masked token prediction and contrastive learning. arXiv preprint arXiv:2106.11250, 2021. 2, 9", + "[33] Jing Tan, Jiaqi Tang, Limin Wang, and Gangshan Wu. Relaxed transformer decoders for direct action proposal generation. In IEEE/CVF International Conference on Computer Vision, 2021. 1", + "[34] Zachary Teed and Jia Deng. Raft: Recurrent all-pairs field transforms for optical flow. In European conference on computer vision, pages 402-419. Springer, 2020. 2, 5, 6", + "[35] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. Video-MAE: Masked autoencoders are data-efficient learners for self-supervised video pre-training. In Advances in Neural Information Processing Systems, 2022. 1, 2, 4, 5, 6, 7, 9", + "[36] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Hervé Jégou. Training data-efficient image transformers & distillation through attention. In International Conference on Machine Learning, 2021. 1", + "[37] Du Tran, Heng Wang, Matt Feiszli, and Lorenzo Torresani. Video classification with channel-separated convolutional networks. In IEEE/CVF International Conference on Computer Vision, 2019. 9", + "[38] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Advances in Neural Information Processing Systems, 2017. 1", + "[39] Pascal Vincent, Hugo Larochelle, Yoshua Bengio, and Pierre-Antoine Manzagol. Extracting and composing robust features with denoising autoencoders. In International Conference on Machine Learning, 2008. 2", + "[40] Pascal Vincent, Hugo Larochelle, Isabelle Lajoie, Yoshua Bengio, and Pierre-Antoine Manzagol. Stacked denoising autoencoders: Learning useful representations in a deep network with a local denoising criterion. Journal of Machine Learning Research, 2010. 2" + ], + "bbox": [ + 78, + 90, + 470, + 900 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[41] Limin Wang, Bingkun Huang, Zhiyu Zhao, Zhan Tong, Yinan He, Yi Wang, Yali Wang, and Yu Qiao. Videomae v2: Scaling video masked autoencoders with dual masking. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14549-14560, 2023. 1, 2", + "[42] Limin Wang, Yu Qiao, and Xiaou Tang. Action recognition with trajectory-pooled deep-convolutional descriptors. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2015, Boston, MA, USA, June 7-12, 2015, pages 4305-4314. IEEE Computer Society, 2015. 3", + "[43] Limin Wang, Zhan Tong, Bin Ji, and Gangshan Wu. TDN: Temporal difference networks for efficient action recognition. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. 3, 9", + "[44] Limin Wang, Yuanjun Xiong, Zhe Wang, Yu Qiao, Dahua Lin, Xiaou Tang, and Luc Van Gool. Temporal segment networks for action recognition in videos. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2019. 3", + "[45] Rui Wang, Dongdong Chen, Zuxuan Wu, Yinpeng Chen, Xiyang Dai, Mengchen Liu, Yu-Gang Jiang, Luowei Zhou, and Lu Yuan. Bevt: Bert pretraining of video transformers. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2, 9", + "[46] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In IEEE/CVF International Conference on Computer Vision, 2021. 1", + "[47] Xiaolong Wang, Ross Girshick, Abhinav Gupta, and Kaiming He. Non-local neural networks. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2018. 9", + "[48] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2, 9", + "[49] Enze Xie, Wenhai Wang, Zhiding Yu, Anima Anandkumar, Jose M Alvarez, and Ping Luo. Segformer: Simple and efficient design for semantic segmentation with transformers. In Advances in Neural Information Processing Systems, 2021. 1", + "[50] Zhenda Xie, Zheng Zhang, Yue Cao, Yutong Lin, Jianmin Bao, Zhuliang Yao, Qi Dai, and Han Hu. Simmim: A simple framework for masked image modeling. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2", + "[51] Xitong Yang, Xiaodong Yang, Sifei Liu, Deqing Sun, Larry Davis, and Jan Kautz. Hierarchical contrastive motion learning for video action recognition. arXiv preprint arXiv:2007.10321, 2020. 3", + "[52] Li Yuan, Yunpeng Chen, Tao Wang, Weihao Yu, Yujun Shi, Francis EH Tay, Jiashi Feng, and Shuicheng Yan. Token-to-token vit: Training vision transformers from scratch onImagenet. In IEEE/CVF International Conference on Computer Vision, 2021. 1", + "[53] Christopher Zach, Thomas Pock, and Horst Bischof. A duality based approach for realtime tv-1 optical flow. In" + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "13503", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Pattern Recognition: 29th DAGM Symposium, Heidelberg, Germany, September 12-14, 2007. Proceedings 29, pages 214-223. Springer, 2007. 5", + "[54] Chen-Lin Zhang, Jianxin Wu, and Yin Li. Actionformer: Localizing moments of actions with transformers. CoRR, abs/2202.07925, 2022. 1", + "[55] Guozhen Zhang, Yuhan Zhu, Haonan Wang, Youxin Chen, Gangshan Wu, and Limin Wang. Extracting motion and appearance via inter-frame attention for efficient video frame interpolation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5682-5692, 2023. 3", + "[56] Kaidong Zhang, Jingjing Fu, and Dong Liu. Flow-guided transformer for video inpainting. In European Conference on Computer Vision, pages 74-90. Springer, 2022. 3", + "[57] Yue Zhao, Yuanjun Xiong, and Dahua Lin. Trajectory convolution for action recognition. In Samy Bengio, Hanna M. Wallach, Hugo Larochelle, Kristen Grauman, Nicolò Cesà-Bianchi, and Roman Garnett, editors, Advances in Neural Information Processing Systems 31: Annual Conference on Neural Information Processing Systems 2018, NeurIPS 2018, December 3-8, 2018, Montréal, Canada, pages 2208-2219, 2018. 3", + "[58] Yuan Zhi, Zhan Tong, Limin Wang, and Gangshan Wu. Mgsampler: An explainable sampling strategy for video action recognition. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 1493-1502. IEEE, 2021. 3", + "[59] Daquan Zhou, Bingyi Kang, Xiaojie Jin, Linjie Yang, Xiaochen Lian, Qibin Hou, and Jiashi Feng. Deepvit: Towards deeper vision transformer. arXiv preprint arXiv:2103.11886, 2021. 1" + ], + "bbox": [ + 78, + 90, + 470, + 540 + ], + "page_idx": 11 + }, + { + "type": "page_number", + "text": "13504", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 11 + } +] \ No newline at end of file diff --git a/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/913ed268-24e1-487c-b23b-995e3fca2c86_model.json b/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/913ed268-24e1-487c-b23b-995e3fca2c86_model.json new file mode 100644 index 0000000000000000000000000000000000000000..ccfe5b6d78540796edc04ce91799249ad587adf6 --- /dev/null +++ b/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/913ed268-24e1-487c-b23b-995e3fca2c86_model.json @@ -0,0 +1,2292 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.044 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.141, + 0.131, + 0.83, + 0.154 + ], + "angle": 0, + "content": "MGMAE: Motion Guided Masking for Video Masked Autoencoding" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.179, + 0.868, + 0.244 + ], + "angle": 0, + "content": "Bingkun Huang\\(^{1,2}\\) Zhiyu Zhao\\(^{1,2}\\) Guozhen Zhang\\(^{1}\\) Yu Qiao\\(^{2}\\) Limin Wang\\(^{1,2,\\text{图}}\\) \n\\(^{1}\\) State Key Laboratory for Novel Software Technology, Nanjing University \\(^{2}\\) Shanghai AI Lab https://github.com/MCG-NJU/MGMAE" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.269, + 0.314, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.301, + 0.474, + 0.664 + ], + "angle": 0, + "content": "Masked autoencoding has shown excellent performance on self-supervised video representation learning. Temporal redundancy has led to a high masking ratio and customized masking strategy in VideoMAE. In this paper, we aim to further improve the performance of video masked autoencoding by introducing a motion guided masking strategy. Our key insight is that motion is a general and unique prior in video, which should be taken into account during masked pretraining. Our motion guided masking explicitly incorporates motion information to build temporal consistent masking volume. Based on this masking volume, we can track the unmasked tokens in time and sample a set of temporal consistent cubes from videos. These temporal aligned unmasked tokens will further relieve the information leakage issue in time and encourage the MGMAE to learn more useful structure information. We implement our MGMAE with an online efficient optical flow estimator and backward masking map warping strategy. We perform experiments on the datasets of Something-Something V2 and Kinetics-400, demonstrating the superior performance of our MGMAE to the original VideoMAE. In addition, we provide the visualization analysis to illustrate that our MGMAE can sample temporal consistent cubes in a motion-adaptive manner for more effective video pre-training." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.686, + 0.21, + 0.701 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.711, + 0.471, + 0.878 + ], + "angle": 0, + "content": "Attention-based Transformer [38] has witnessed great success in computer vision since the introduction of Vision Transformer (ViT) [12]. It has been applied for a variety of vision tasks and obtains state-of-the-art performance, such as image classification [36, 59, 52], object detection [23, 46], semantic segmentation [49], and object tracking [8]. Thanks to this high performance, ViT models have been also applied to the video domain for action recognition [5, 1] and detection [33, 54]. However, the high capacity of Transformer often demands pre-training on a large-scale dataset to reduce the over-fitting risk of subsequent fine" + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.267, + 0.687, + 0.334 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.532, + 0.341, + 0.663, + 0.355 + ], + "angle": 0, + "content": "(a) original video clip" + }, + { + "type": "image", + "bbox": [ + 0.506, + 0.355, + 0.684, + 0.422 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.536, + 0.427, + 0.657, + 0.441 + ], + "angle": 0, + "content": "(c) random masking" + }, + { + "type": "image", + "bbox": [ + 0.706, + 0.267, + 0.886, + 0.334 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.746, + 0.341, + 0.848, + 0.354 + ], + "angle": 0, + "content": "(b) tube masking" + }, + { + "type": "image", + "bbox": [ + 0.703, + 0.354, + 0.892, + 0.421 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.716, + 0.427, + 0.878, + 0.441 + ], + "angle": 0, + "content": "(d) motion guided masking" + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.453, + 0.895, + 0.575 + ], + "angle": 0, + "content": "Figure 1: Comparison of different masking strategies. Masked autoencoding [11, 17] has been explored in video domain for self-supervised pre-training by employing different masking strategies: random masking [14] and tube masking [35]. We propose to track masking maps under the guidance of motion information (termed as motion guided masking). Our resulting MGMAE can build a more challenging and meaningful task for video pre-training." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.583, + 0.892, + 0.628 + ], + "angle": 0, + "content": "tuning. Therefore, an effective pretraining strategy of ViT is particularly important for obtaining excellent performance in the video domain due to the smaller video dataset." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.63, + 0.895, + 0.902 + ], + "angle": 0, + "content": "The early video transformers [1, 5] often rely on the pre-training of image-based transformer derived from the large-scale image dataset [10]. This pre-training scheme makes the learnt video model to be naturally biased by image-based ViTs. Recently, masked autoencoding (MAE) [35, 14, 41] has been explored for pre-training video transformer on the video dataset due to its simplicity and promising result in image domain [17]. However, unlike the image, video data is equipped with an extra time dimension and exhibits the unique property of temporal redundancy and correlation. This property requires some customized designs on video masked autoencoder compared with image-based MAE. For example, VideoMAE and MAE-ST both propose to use an extremely high masking ratio in video masked autoencoder pre-training to improve its performance. In addition, VideoMAE devises a tube masking strategy of dropping tokens at the same position across frames to further relieve the information leakage in time. This tube masking" + }, + { + "type": "page_footnote", + "bbox": [ + 0.1, + 0.888, + 0.361, + 0.901 + ], + "angle": 0, + "content": "\\(\\boxtimes\\) : Corresponding author (lmwang@nju.edu.cn)." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13493" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.08, + 0.092, + 0.468, + 0.151 + ], + "angle": 0, + "content": "approach, though straightforward, makes the assumption of no or small motion occurring between adjacent frames. Such an assumption might be not true for some scenarios with high-speed motion." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.16, + 0.468, + 0.416 + ], + "angle": 0, + "content": "Based on the above analysis, in this paper, we aim to propose a new masking strategy for improving video masked autoencoder pre-training, by explicitly using motion information to reduce information leakage in time. Specifically, we devise the Motion Guided Masking in the video masked encoder processing and the resulted masked autoencoder is termed as MGMAE. Motion is general prior information contained by video. The optical flow representation explicitly encodes the movement of each pixel from the current frame to the next one. We propose to use this optical flow to align masking maps between adjacent frames to build consistent masking volumes across time. The consistent masking volumes enable to build a more challenging reconstruction task by enforcing only a small set of cube tracks visible to the encoder. Hopefully, this motion guided masking can further relieve the risk of information leakage in time and encourage learning more meaningful visual representations." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.425, + 0.468, + 0.68 + ], + "angle": 0, + "content": "More specifically, we use an online and lightweight optical flow estimator (RAFT [34]) to capture motion information, which could be seamlessly integrated into the existing VideoMAE framework. To build the temporally consistent masking volume, we first randomly generate an initial masking map at the base frame. Then, we use the estimated optical flow to warp the initial masking map to adjacent frames. With multiple warping operations, we build the temporal consistent masking volume for all frames in the video. Finally, based on this masking volume, we sample a set of visible tokens to MAE encoders with top-k selection based on a frame-wise manner. The same autoencoding process with the original VideoMAE is applied to these sampled tokens for video pretraining. With this simple motion guided masking, we are able to further increase the difficulty of video pre-training task and thus lead to a better pre-trained model for subsequent fine-tuning." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.69, + 0.468, + 0.899 + ], + "angle": 0, + "content": "We mainly verify the effectiveness of the proposed MGMAE on the datasets of Something-Something V2 [16] and Kinetics-400 [20] by comparing them with the original tube masking in VideoMAE. The results demonstrate that MGMAE pre-training can result in more powerful video foundation models with higher fine-tuning accuracy on the downstream tasks. In particular, on the motion-centric benchmark of Something-Something, the improvement of MGMAE is more evident, implying that our motion guided masking is adaptive to motion variations and can better capture temporal structure information for pre-training. We hope our findings can inspire some specific and unique designs in video masked autoencoding with respect to image counterparts." + }, + { + "type": "title", + "bbox": [ + 0.505, + 0.091, + 0.64, + 0.105 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.116, + 0.892, + 0.507 + ], + "angle": 0, + "content": "Masked Visual Modeling. Masked autoencoder is a long-standing unsupervised learning framework in computer vision. The early work presented general form of denoising autoencoder [40, 39] for learning representation by reconstructing the clean signal from the noisy inputs. The other work [27] also treated masking modeling as inpainting missing regions from the surrounding context by using convolutions. Inspired by the great success of masked language modeling [11], some works also attempted to apply this pretraining paradigm to the vision domain for self-supervised pre-training. For example, iGPT [7] followed the GPT work [30] in NLP and processed a sequence of pixels for casual prediction of the next pixels. The original ViT [12] used the masked token prediction as a self-supervised training step on large-scale image datasets but failed to obtain impressive results. Recently, several interesting works have obtained a great breakthrough in self-supervised image pre-training by using masked image modeling, such as BEiT [3], SimMIM [50], and MAE [17]. BEiT [3] directly followed the BERT framework and proposed to predict the discrete token label for masked patches, by requiring an explicit tokenizer to build the token dictionary. SimMIM [50] and MAE [17] shared the same design of directly predicting the pixels of masked patches without any tokenizer design. Furthermore, MAE [17] devised an asymmetric encoder-decoder architecture to speed up the masked image pre-training." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.51, + 0.892, + 0.9 + ], + "angle": 0, + "content": "Since the great success in masked image modeling, some works have tried to extend this new pre-training paradigm to the video domain for self-supervised video pre-training. BEVT [45] and VIMPAC [32] proposed to learn video representation by predicting discrete visual tokens in a similar way to BEiT. However, their performance improvement in video action recognition is limited. MaskFeat [48] used the HOG features [9] as the reconstructed targets of masked patches and achieved excellent performance on the video recognition with a multi-scale vision transformer. VideoMAE [35] and MAE-ST [14] extended the image MAE to the video domain for representation learning with vanilla vision transformer. They both proposed to use an extremely high masking ratio to deal with video data redundancy. Meanwhile, VideoMAE [35] used the tube masking to further increase the difficulty of reconstruction. Several works building upon VideoMAE have emerged. For instance, MAR [29] reduced both training and inference costs by introducing running cell masking. Meanwhile, VideoMAE V2 [41] proposes a dual masking strategy to decrease pre-training overhead, and by expanding both the model size and dataset, it further explores the scalability of VideoMAE. Our proposed motion guided masking aims to improve the performance of VideoMAE by building a more challenging masking and reconstruction task. In contrast to the original VideoMAE, our MGMAE explicitly use the optical flow to align the masking maps" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.947, + 0.518, + 0.956 + ], + "angle": 0, + "content": "13494" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.122 + ], + "angle": 0, + "content": "across frames and generate the temporal consistent masking volume to sample a set of visible tokens." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.139, + 0.473, + 0.835 + ], + "angle": 0, + "content": "Motion Guided Modeling. Motion information, such as optical flow, is a general prior information in videos and represents the unique characteristics distinct from images. Optical flow has been widely introduced to provide a strong prior in both low-level and high-level vision tasks on video. For low-level video tasks, the motion is often used to align the information of auxiliary frames to the corresponding region of the target frame. In the case of video super-resolution, BasicVSR++ [6] uses optical flow to enhance the appearance of low-resolution frames by transferring features from neighbor frames. For video inpainting, Zhang et al. [56] exploits the motion difference extracted by optical flows to instruct the attention retrieval in transformer for high-fidelity video inpainting. As for video frame interpolation, mainstream methods leverage optical flow directly on the image to synthesize the intermediate frame, such as DAIN [4] and RIFE [18], while Zhang et al. [55] introduces a unified operation utilizing inter-frame attention to concurrently extract motion and appearance information, and blends a hybrid CNN and Transformer design for efficiency and fine-grained detail preservation. For high-level video tasks, the optical flow is directly used as a data modality as network input for action recognition [44, 31]. TDD [42] utilized motion trajectories to pool deep convolutional features for action recognition. Trajectory Convolution [57] incorporated the motion information into temporal convolutional kernel design. MSNet [21] proposes a pluggable MotionSqueeze module to generate motion information across frames. VideoMS [19] generates mask maps by calculating the feature difference after patch embedding, making an attempt at dynamically adjusting mask positions. AdaMAE [2] introduces an end-to-end trainable adaptive masking strategy for MAEs, leveraging an auxiliary sampling network to prioritize tokens from high spatiotemporal information regions. Yang et al. [51] leverage hierarchical motion information to improve the extracted video features. MotionFormer [28] employed the trajectory for attention computation in the video transformer. TEA [22] and TDN [43] used RGB difference to approximate the motion information and incorporate this information into the video CNN backbone design. MGSampler [58] explored the motion information to select a subset of representative frames for efficient video action recognition. Our MGMAE shares the same spirit with these motion guided modeling works. We focus on employing motion information as a cue to generate masking maps for masked video pre-training." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.845, + 0.169, + 0.86 + ], + "angle": 0, + "content": "3. Method" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.472, + 0.901 + ], + "angle": 0, + "content": "In this section, we first revisit the pre-training paradigm of VideoMAE to well introduce our MGMAE in Sec. 3.1." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.895, + 0.138 + ], + "angle": 0, + "content": "Then we present the details of motion guided masking map generation in Sec. 3.2. Finally, we describe the MGMAE pretraining under temporal consistent masking maps in Sec. 3.3." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.15, + 0.693, + 0.165 + ], + "angle": 0, + "content": "3.1. VideoMAE revisited" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.174, + 0.894, + 0.235 + ], + "angle": 0, + "content": "VideoMAE is a simple masked video autoencoder with an asymmetric encoder-decoder architecture with an extra cube embedding to handle the input sampled frames. Next, we briefly revisit its implementation detail." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.26, + 0.895, + 0.373 + ], + "angle": 0, + "content": "Cube Embedding. VideoMAE divides the input video clip \\(\\mathbf{I}\\) of size \\(T\\times 3\\times H\\times W\\) into non-overlapping cubes \\(\\mathbf{C} = \\{\\mathbf{C}_i\\mid \\mathbf{C}_i\\in \\mathbb{R}^{2\\times 16\\times 16\\times 3}\\}_{i = 1}^N\\), where \\(N = \\frac{T}{2}\\times \\frac{H}{16}\\times \\frac{W}{16}\\) is the number of cubes. Then apply cube embedding on the cubes to produce the video tokens \\(\\mathbf{T} = \\{\\mathbf{T}_i\\mid \\mathbf{T}_i\\in \\mathbb{R}^D\\}_{i = 1}^N\\), where \\(T_{i}\\) represents the cube embedding with positional encoding, and \\(D\\) is the channel." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.398, + 0.895, + 0.535 + ], + "angle": 0, + "content": "Masking Strategy. VideoMAE uses the tube masking strategy with an extremely high masking ratio \\(\\rho\\) (i.e. \\(90\\%\\)), which samples the same spatial positions across all frames of the input video clip. Specifically, VideoMAE first generate a \\(\\frac{H}{16} \\times \\frac{W}{16}\\) binary mask map \\(\\mathbf{M}'\\) where 0 represents unmasked and 1 represents masked. Then it replicates it in temporal dimension and then flattens it to produce the token-level mask map \\(\\mathbf{M}\\) whose size is \\(N\\) for the input video clip. We denote \\(\\mathbb{M}\\) as the masking maps." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.559, + 0.894, + 0.65 + ], + "angle": 0, + "content": "Encoder. The encoder is a vanilla ViT with joint space-time attention [5]. For computation efficiency, only the unmasked visible tokens \\(\\mathbf{T}^v = \\{\\mathbf{T}_i\\}_{i\\notin \\mathbb{M}}\\) added with the fixed positional embedding are fed into the encoder to obtain the latent features \\(\\mathbf{Z}\\) of size \\(N_v\\times D\\), where \\(N_{v} = \\lfloor (1 - \\rho)N\\rfloor\\) is the total number of the unmasked visible tokens." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.675, + 0.894, + 0.78 + ], + "angle": 0, + "content": "Decoder. The decoder is a narrower and shallower ViT than the encoder. It takes the concatenated token sequences as input, which is formed by the concatenation between the latent features \\(\\mathbf{Z}\\) and the learnable [MASK] tokens with the fixed position embedding added, to reconstruct the normalized video cubes \\(\\hat{\\mathbf{C}} = \\left\\{\\hat{\\mathbf{C}}_i \\mid \\hat{\\mathbf{C}}_i \\in \\mathbb{R}^{2 \\times 16 \\times 16 \\times 3}\\right\\}_{i=1}^N\\)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.801, + 0.892, + 0.856 + ], + "angle": 0, + "content": "Loss. The pre-training object is to minimize the Mean Square Error Loss between the normalized \\(\\mathbf{C}\\) and \\(\\hat{\\mathbf{C}}\\) on the masked positions, i.e. \\(\\frac{1}{\\rho N} \\sum_{i \\in \\mathbb{M}} \\left| \\hat{\\mathbf{C}}_i - \\mathrm{norm}(\\mathbf{C}_i) \\right|^2\\)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "After the pre-training, the encoder will be used as the backbone network to fine-tune on the downstream tasks to obtain a specialized model." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13495" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.107, + 0.096, + 0.862, + 0.384 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.404, + 0.896, + 0.482 + ], + "angle": 0, + "content": "Figure 2: Pipeline of MGMAE. Our MGMAE follows the simple pipeline of masking and reconstruction for video self-supervised pre-training. Our core design is to propose a motion guided masking strategy to generate temporal consistent masking volume. With this masking volume, we track the visible cubes and attain temporal consistency for masking maps. As a result, we can build a more challenging reconstruction task and encourage extracting more effective representations during masked self-supervised pretraining." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.506, + 0.345, + 0.525 + ], + "angle": 0, + "content": "3.2. Motion Guided Masking Map" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.539, + 0.474, + 0.903 + ], + "angle": 0, + "content": "Time is a unique characteristic of video and has different properties with the space dimension. When devising masked video autoencoder, we need to carefully take this extra time dimension into account and come up with a customized design. Information leakage in time is an important issue in masked video pre-training. When information leakage occurs, the model can easily reconstruct the masked cubes based on the visible tokens of adjacent frames. In this case, it will greatly reduce the difficulty of the reconstruction task and lead to a pre-trained model with poor fine-tuning performance. A trivial solution to information leakage is to increase the masking ratio. VideoMAE [35] and MAE-ST [14] increase the masking ratio to \\(90\\%\\) to greatly increase the difficulty of reconstruction. In addition, VideoMAE makes the small motion assumption and adapts the tube masking strategy, which masks the same spatial position in all frames. However, this small motion prior is not always true for motion-dominated videos. A more reasonable approach is to keep each object in the video clip visible or invisible at all times. To achieve this goal, we propose the motion guided masking strategy to replace the tube masking strategy in VideoMAE. The strategy has two procedures: we first use the optical flow as guidance to generate temporally consistent masking volumes of the input video clip" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.507, + 0.892, + 0.551 + ], + "angle": 0, + "content": "and then sample the unmasked visible tokens based on the temporal consistent masking volume. We will detail these two procedures in Sec. 3.2 and Sec. 3.3." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.553, + 0.892, + 0.583 + ], + "angle": 0, + "content": "In general, the procedure for generating the temporal consistent masking volumes has four steps as follows." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.595, + 0.891, + 0.623 + ], + "angle": 0, + "content": "- Step 1: Determine the base frame \\(\\mathbf{I}_b\\), where \\(b\\) is the index of the base frame." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.635, + 0.891, + 0.667 + ], + "angle": 0, + "content": "- Step 2: Randomly generate a pixel-level initial mask map \\(\\mathbf{M}_b\\) with size \\(H \\times W\\) as the mask map of \\(\\mathbf{I}_b\\)." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.675, + 0.891, + 0.707 + ], + "angle": 0, + "content": "- Step 3: Extract the dense flows \\(\\mathbf{F}\\) bidirectionally from the base frame \\(\\mathbf{I}_b\\) in the input video clip \\(\\mathbf{I}\\)." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.716, + 0.891, + 0.775 + ], + "angle": 0, + "content": "- Step 4: Warp the initial masking map \\(\\mathbf{M}_b\\) under the guidance of dense flows \\(\\mathbf{F}\\) and progressively build the temporal consistent masking volume \\(\\mathbf{M}\\) of size \\(T \\times H \\times W\\)." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.595, + 0.891, + 0.775 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Determine the base frame. By default, we choose the middle frame as the base frame. In motion guided masking, we need to ensure all objects in the base frame remain consistently visible or invisible in all frames of the input clip. Note that objects may (dis)appear over time due to object or camera movement, and warping the masking map under optical flow can result in some holes due to pixels mapped" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "13496" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.471, + 0.152 + ], + "angle": 0, + "content": "out of bounds. So the choice of the base frame may have an impact on the suppression of information leakage. We ablate the choice of the base frame in Sec. 4.2 and the middle frame is the optimal choice." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.17, + 0.47, + 0.29 + ], + "angle": 0, + "content": "Generate the initial mask map. We initialize a pixel-level masking map for the base frame with the distribution of the Gaussian Mixture Model (GMM). We use the masking map to indicate the visible or invisible state of the cubes in the base frame. Previous masking strategies usually adapt a token-level binary initialization, i.e. either all 0 or all 1 within each token of size \\(2 \\times 16 \\times 16\\), which actually breaks the continuity of the object surface texture." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.29, + 0.471, + 0.452 + ], + "angle": 0, + "content": "Specifically, we first randomly pick \\(\\hat{N}_v = \\left\\lfloor (1 - \\rho) \\times \\frac{H}{16} \\times \\frac{W}{16} \\right\\rfloor\\) tokens whose centers are denoted with \\(c = \\{\\vec{c_i} : (c_{i1}, c_{i2})\\}_i^{\\hat{N}_v}\\). Then we generate 2D Gaussian distributions \\(\\mathcal{N}_i(c_i, \\sigma^2)\\) centered on the midpoint of each token, where \\(\\sigma\\) is the standard deviation and taken as the cube size (16, 16). Thus we will obtain the mixed Gaussian distribution \\(\\mathcal{P}(c, \\sigma^2) = \\sum_{i}^{\\hat{N}_v} \\mathcal{N}_i(\\vec{c_i}, \\sigma^2)\\) corresponding to the base frame. And the probability density function of the mixed Gaussian distribution is used to indicate the probability that the cube (token) is visible in the base frame." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.469, + 0.47, + 0.603 + ], + "angle": 0, + "content": "Extract optical flows. We use both online and offline alternative methods to extract optical flow. Online method adapts RAFT [34] (the small version) to estimate the flows of the input video clip. Offline method applies the traditional TVL1 [53] algorithm to extract the dense flows between all adjacent frames in advance. We perform the consistent crop-resize-rescale operations when reading flows. Online and offline methods achieve the similar results. More details see in Sec. 4.2." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.605, + 0.469, + 0.636 + ], + "angle": 0, + "content": "In practice, we only extract the flows \\(\\mathbf{F}\\) forward and backward from the base frame \\(\\mathbf{I}_b\\), i.e." + }, + { + "type": "equation", + "bbox": [ + 0.145, + 0.643, + 0.47, + 0.663 + ], + "angle": 0, + "content": "\\[\n\\mathbf {F} = \\left\\{v _ {i \\rightarrow i + 1} \\right\\} _ {i = 1} ^ {b - 1} \\cup \\left\\{v _ {i \\rightarrow i - 1} \\right\\} _ {i = b + 1} ^ {T}, \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.672, + 0.418, + 0.687 + ], + "angle": 0, + "content": "where the flow \\( v_{i\\rightarrow j} \\) denotes the flow from \\( \\mathbf{I}_i \\) to \\( \\mathbf{I}_j \\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.705, + 0.471, + 0.901 + ], + "angle": 0, + "content": "Warp masking maps with flows. We utilize the method of backward warping to generate the temporal consistent masking map of the video clip in a progressive manner. Forward warping \\(\\phi_F\\) and backward warping \\(\\phi_B\\) are two opposite patterns of warping. Both can be effectively employed to construct the masking volume from the initial masking map. Regrettably, forward warping suffers from hole or occlusion problems, that is, no flow vectors may pass to a certain pixel, or there may be multiple flow vectors passing to the same pixel. In contrast, backward warping maps the pixels of a given map one by one to individual locations. It's noteworthy that while backward warping doesn't escape from the issue of holes caused by mapping out of bounds, these holes are" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.168 + ], + "angle": 0, + "content": "usually fewer than in forward warping and tend to occur at the boundaries of the map, thus causing less damage to the information distribution. For the holes caused by backward warping, we fill them with the values of \\(\\mathbf{M}_b\\) at the same position to simulate the tube masking strategy." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.168, + 0.892, + 0.197 + ], + "angle": 0, + "content": "Formally, given the flows \\(\\mathbf{F}\\) and the base frame masking volume \\(\\mathbf{M}_b\\), the mask map \\(\\mathbf{M}_i\\) of \\(\\mathbf{I}_i\\) can be constructed as" + }, + { + "type": "equation", + "bbox": [ + 0.549, + 0.208, + 0.892, + 0.263 + ], + "angle": 0, + "content": "\\[\n\\mathbf {M} _ {i} = \\left\\{\\begin{array}{l l}\\phi_ {B} \\left(\\mathbf {M} _ {i + 1}, v _ {i \\rightarrow i + 1}\\right),&1 \\leq i < b\\\\\\mathbf {M} _ {b},&i = b\\\\\\phi_ {B} \\left(\\mathbf {M} _ {i - 1}, v _ {i \\rightarrow i - 1}\\right),&b < i \\leq T\\end{array}. \\right. \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.274, + 0.892, + 0.336 + ], + "angle": 0, + "content": "Subsequently, the entire masking volume \\(\\mathbf{M} = \\{\\mathbf{M}_i\\}_{i=1}^T\\) of the video clip \\(\\mathbf{I}\\) can be constructed by backward warping the flows \\(\\mathbf{F}\\) bidirectionally, originating from the base frame mask map \\(\\mathbf{M}_b\\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.345, + 0.7, + 0.359 + ], + "angle": 0, + "content": "3.3. Motion Guided MAE" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.368, + 0.895, + 0.565 + ], + "angle": 0, + "content": "We build our MGMAE based on the above motion guided masking map. The temporal consistent masking volume indicates the probability that the corresponding position in the adjacent frame is visible under optical flow tracking. In order to suppress information leakage as much as possible, we sample the video tokens with the highest visible probability along the temporal dimension. Specifically, we first perform average pooling with kernel size \\(2 \\times 16 \\times 16\\) on the masking volume \\(\\mathbf{M}\\) to obtain the token-level masking volume \\(\\mathbf{M}'\\) of size \\(\\frac{T}{2} \\times \\frac{H}{16} \\times \\frac{W}{16}\\). Then we pick the top-\\(\\hat{N}_v\\) locations of each mask map of size \\(\\frac{H}{16} \\times \\frac{W}{16}\\) along the temporal dimension and thus sample \\(N_v\\) corresponding video tokens as the unmasked visible tokens." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.566, + 0.895, + 0.672 + ], + "angle": 0, + "content": "These sampled tokens according to our temporal consistent masking volume are fed into the asymmetric encoder-decoder for autoencoding based pre-training. The resulted pre-training framework is called Motion Guided Masked Autoencoder (MGMAE). The pre-trained model by our MGMAE is applied in the same way with the original Video-MAE for fine-tuning the downstream tasks." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.689, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Discussion. Previous works [35, 14] extended MAE to the video domain. They opted for the random (agnostic) masking and tube (space-only) masking strategies, respectively. Random masking introduces no explicit inductive bias about the video's space and time dimension. It aims to present a unified feature representation learning framework with minimal domain knowledge. We argue that although this idea is simple, time is inherently a distinctive dimension from space. By recognizing this, we could better leverage this prior information for enhanced video masked autoencoding. Tube masking assumes that a large area of the frame contains no or small motion, and thus masking the same position across frames could greatly reduce the information leakage risk. However, for motion-dominated video datasets such as" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13497" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.471, + 0.184 + ], + "angle": 0, + "content": "Something-Something, this assumption will no longer hold true. Our proposed motion guided masking offers a more general and conceptually simple solution to take temporal correlation into account. It could be viewed as an adaptive video masking strategy and create more challenging yet meaningful tasks in video pre-training." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.198, + 0.21, + 0.215 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.224, + 0.173, + 0.239 + ], + "angle": 0, + "content": "4.1. Dataset" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.247, + 0.474, + 0.52 + ], + "angle": 0, + "content": "Following the original VideoMAE, we evaluate our MGMAE on Kinetics-400 (K400) [20] and Something-Something V2 (SSV2) [16]. K400 contains about 240k training videos and 20k validation videos from YouTube and the actions in K400 are usually coupled with specific objects or scenes, such as brushing teeth and playing piano. While SSV2 contains about 169k training videos and 25k validation videos, and the categories in SSV2 only care about specific motion patterns (e.g. push, pull). We first pre-train the video transformer with our MGMAE on the corresponding dataset for self-supervised representation learning. Then, we report the fine-tuning performance of pre-trained models on the target datasets for action recognition. In our MGMAE pretraining, we generally follow the setting and implementation of the original VideoMAE [35]. We use the RAFT [34] to extract optical flow due to its efficiency and accuracy in our MGMAE pre-training. The implementation details on our MGMAE could found in the appendix." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.531, + 0.242, + 0.546 + ], + "angle": 0, + "content": "4.2. Ablation Studies" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.555, + 0.472, + 0.661 + ], + "angle": 0, + "content": "In this subsection, we conduct in-depth ablation experiments on the choice in each step of our motion guided masking strategy. We pre-train the ViT-base model 800 epochs on the SSV2 dataset with 16 80G-A100 GPUs, and then fine-tune the encoder on the SSV2 dataset for action recognition. All models share the same training schedule and report the 2 clips \\(\\times 3\\) crops accuracy." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.683, + 0.47, + 0.773 + ], + "angle": 0, + "content": "Choice of the base frame. In this study, we investigate the influence of base frame selection for initial masking generation process. We compare the middle frame as the based frame with either the first or a random frame, and the result is shown in Tab. 1a. It implies the middle frame is the best." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Warping method with optical flow. We compare two kinds of warping methods to align masking maps across frames as explained in Sec. 3.2. As previously mentioned above, the forward warping often leads to more severe occlusion and hole problems in the masking warping process. On the contrary, backward warping can effectively relieve this issue and ensure a more smooth masking warping. The" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.122 + ], + "angle": 0, + "content": "result in Tab. 1b demonstrates that back warping contributes to better performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.143, + 0.894, + 0.265 + ], + "angle": 0, + "content": "Sampling strategy of top-k visible tokens. We examine and compare the two sampling strategies to select the visible tokens based on our temporal consistent masking volume. Frame-level strategy samples the top-k locations for each frame independently, while clip-level strategy samples the top-k locations for the entire video jointly. As in Tab. 1c, the frame-level top-k sampling strategy achieves slightly better performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.285, + 0.895, + 0.451 + ], + "angle": 0, + "content": "Masking initialization at the base frame. We ablate the choice of generating the initial masking at the base frame as shown in Tab. 1d. The token-level initialization method divides the mask map into \\(\\frac{H}{16} \\times \\frac{W}{16}\\) tokens of size \\(16 \\times 16\\), and randomly sets \\(90\\%\\) tokens to 0 (representing masked) and \\(10\\%\\) tokens to 1 (representing unmasked). The pixel-level initialization method randomly sets \\(90\\%\\) pixels to 0 and \\(10\\%\\) pixels to 1. The initialization process of the mixed Gaussian method has been detailed in Sec. 3.2. The result demonstrates that the mixed Gaussian initialization method works the best." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.472, + 0.895, + 0.715 + ], + "angle": 0, + "content": "Hole filling method. We investigate the various methods to handle the holes problem brought by the mapping out of bound in backward warping in Tab. 1e. To determine the real holes caused by warping, we set the 0 in the initial mask map to value \\(1e - 8\\), and then the locations equal to 0 in new mask maps are treated as the holes. We experiment with 5 methods to fill the holes: Invisible method fills all holes with 0, while Visible method fills all holes with 1. Random method randomly fills the holes to 0 with probability of masking ratio \\(\\rho\\) and to 1 with probability of \\(1 - \\rho\\). Previous map method fills holes using the values from the same spatial positions as the last generated mask map. Conversely, Tube method fills the holes with the value from the corresponding positions of the initial mask map, aligning with tube masking principles. We see that the tube method performs the best among all the methods." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.897, + 0.903 + ], + "angle": 0, + "content": "Method of optical flow estimation. We evaluate the effect of different methods of optical flow estimation as shown in Tab. 1f. For the offline method, we use the TVL1 algorithm to extract optical flows in advance and it achieve a comparable accuracy to the online RAFT optical flow. Although VideoMAE is 1.3 times faster to train than MGMAE with RAFT-small (set to 6 testing iterations) to estimate flows, MGMAE has a clear advantage in terms of performance and reducing the risk of overfitting. We find that the offline method is not much faster than the online method because IO (reading optical flow from disk) will be a bottleneck to" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "13498" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.089, + 0.316, + 0.148 + ], + "angle": 0, + "content": "
caseAcc@1Acc@5
first frame70.592.7
random frame70.692.9
middle frame71.093.1
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.078, + 0.153, + 0.327, + 0.194 + ], + "angle": 0, + "content": "(a) Base frame selection. We perform ablation study to select the base frame as the first, random or the middle frame." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.216, + 0.315, + 0.274 + ], + "angle": 0, + "content": "
caseAcc@1Acc@5
token rand.70.993.0
pixel rand.70.893.0
mixed Gauss71.093.1
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.077, + 0.28, + 0.327, + 0.335 + ], + "angle": 0, + "content": "(d) Masking initialization. We compare three methods to generate the masking map in the base frame. Two binary random methods and one mixed Gaussian method." + }, + { + "type": "table", + "bbox": [ + 0.351, + 0.096, + 0.586, + 0.14 + ], + "angle": 0, + "content": "
caseAcc@1Acc@5
forward70.592.9
backward71.093.1
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.348, + 0.146, + 0.597, + 0.188 + ], + "angle": 0, + "content": "(b) Warping method. We choose forward or backward warping method for aligning masking maps." + }, + { + "type": "table", + "bbox": [ + 0.368, + 0.203, + 0.597, + 0.287 + ], + "angle": 0, + "content": "
caseAcc@1Acc@5
random70.892.9
invisible70.792.8
visible70.893.1
previous map70.692.8
tube71.093.1
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.36, + 0.294, + 0.609, + 0.351 + ], + "angle": 0, + "content": "(e) Hole filling. We choose some baseline choices to fill the value in the hole place caused by warping. We also use the tube filling consistent with the tube masking." + }, + { + "type": "table", + "bbox": [ + 0.647, + 0.096, + 0.882, + 0.14 + ], + "angle": 0, + "content": "
caseAcc@1Acc@5
clip-level70.792.9
frame-level71.093.1
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.643, + 0.147, + 0.894, + 0.202 + ], + "angle": 0, + "content": "(c) Sampling strategy. We perform a study to choose the visible token generation strategy based on motion guided masking volume." + }, + { + "type": "table", + "bbox": [ + 0.647, + 0.21, + 0.886, + 0.28 + ], + "angle": 0, + "content": "
methodtimeAcc@1
None (VideoMAE)32 h69.6
TVL1 (offline)41 h71.2
RAFT with 6 iters43 h71.3
RAFT with 12 iters56 h71.0
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.643, + 0.287, + 0.894, + 0.343 + ], + "angle": 0, + "content": "(f) Method of optical flow estimation. We perform the ablation study to investigate the influence of different methods of optical flow estimation." + }, + { + "type": "table_footnote", + "bbox": [ + 0.076, + 0.361, + 0.895, + 0.438 + ], + "angle": 0, + "content": "Table 1: Parts of the ablation experiments on the Something-Something V2 dataset. Our MGMAE pre-training is implemented with the 16-frame vanilla ViT-B backbone. All models are pre-trained for 800 epochs and the masking ratio is \\(\\rho = 90\\%\\). The inference protocol is to report the fine-tuning action recognition accuracy with 2 clips \\(\\times\\) 3 crops. The default choice for our model is colored in gray. Although the default setting is not optimal in terms of the method of optical flow estimation, we believe that this does not affect the conclusions of the ablation experiments." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.465, + 0.47, + 0.51 + ], + "angle": 0, + "content": "increase the training speed. Note that our default setting is not optimal, but the conclusions drawn in other ablation experiments should not be impacted." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.531, + 0.473, + 0.835 + ], + "angle": 0, + "content": "Masking ratio. The performance of MGMAE highlights the importance of improving masking strategies even at high masking rates (e.g. \\(90\\%\\)). However, after applying MGMAE, it remains questionable whether such high masking rates are still necessary. Indeed, as pointed out by [35, 14], blindly increasing the masking rate could potentially degrade the model performance. Our ablation study presented in Fig. 3 shows that sustaining a extremely high masking rate of over \\(80\\%\\) is also crucial even with MGMAE. We think the video background and large objects mainly drive the need for a high masking ratio. Video backgrounds are often wide and simple. If the mask ratio is not high enough, the model can still rebuild pixels from other background parts, even if nearby frames mask similar sections. For large objects, a lower ratio might let the model use the texture from a different part of the object when another section is masked. It can also be observed that MGMAE performs optimally with \\(85\\%\\) masking ratio, but \\(90\\%\\) still seems to be a decent choice when considering the trade-off between training efficiency and performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Exposure of masked objects. Another proposition worth considering is whether occasional exposure of masked objects help with masked video modeling pre-train. We com" + }, + { + "type": "image", + "bbox": [ + 0.517, + 0.466, + 0.885, + 0.645 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.539, + 0.665, + 0.852, + 0.68 + ], + "angle": 0, + "content": "Figure 3: The effect of masking ratio on SSV2." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.71, + 0.895, + 0.802 + ], + "angle": 0, + "content": "pleted a complementary experiment. Specifically, after building the masking volume, we add Gaussian noise on the mask map of one randomly selected frame. This modification may provide a chance for masked objects to be exposed. The results showed an accuracy of \\(71.2\\%\\), slightly higher than the default setting of \\(71.0\\%\\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.816, + 0.845, + 0.832 + ], + "angle": 0, + "content": "4.3. Main Results and Visualization Analysis" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.895, + 0.901 + ], + "angle": 0, + "content": "After the detailed ablation study on the design of MGMAE, we further perform a deeper analysis by comparing it with the original VideoMAE. We also provide some intermediate visualization results to illustrate the motion guided" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13499" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.091, + 0.089, + 0.458, + 0.191 + ], + "angle": 0, + "content": "
ModelEpochsK400SSV2
VideoMAE800 / 8000.58750.5278
MGMAE0.64620.5820
Δ loss-Δ + 0.0605Δ + 0.0542
VideoMAE1600 / 24000.58090.5122
MGMAE0.63780.5659
Δ loss-Δ + 0.0569Δ + 0.0537
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.201, + 0.471, + 0.23 + ], + "angle": 0, + "content": "Table 2: Pre-train loss comparison of MGMAE and Video-MAE." + }, + { + "type": "table", + "bbox": [ + 0.101, + 0.246, + 0.447, + 0.35 + ], + "angle": 0, + "content": "
ModelEpochsK400SSV2
VideoMAE800 / 80080.069.6
MGMAE81.271.0
Δ Acc@1-Δ + 1.2%Δ + 1.4%
VideoMAE1600 / 240081.570.8
MGMAE81.872.3
Δ Acc@1-Δ + 0.3%Δ + 1.5%
" + }, + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.36, + 0.468, + 0.375 + ], + "angle": 0, + "content": "Table 3: Accuracy comparison of MGMAE and VideoMAE." + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.392, + 0.462, + 0.543 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.555, + 0.471, + 0.586 + ], + "angle": 0, + "content": "Figure 4: Comparative Accuracy of MGMAE and Video-MAE by Class." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.615, + 0.199, + 0.629 + ], + "angle": 0, + "content": "sampling process." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.652, + 0.47, + 0.818 + ], + "angle": 0, + "content": "Pre-train loss implies a more challenging task. The core design of MGMAE is to dynamically sample the positions of masked token under the guidance of optical flows and aims at increasing the difficulty of the reconstruction task. As can be seen in Tab. 2, the pre-train loss of MGMAE is always larger than that of VideoMAE by more than 0.05. This loss gap implies motion guided masking further suppresses information leakage and indeed constructs a more challenging mask-reconstruct pretext task for masked video modeling. This more difficult task would like to encourage learning more effective representations." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.468, + 0.902 + ], + "angle": 0, + "content": "Detailed breakdown of comparison between MGMAE and VideoMAE. To understand the distinct impacts of the MGMAE and VideoMAE masking strategies on video model pre-training, we delved deeper into the per-class accuracy" + }, + { + "type": "image", + "bbox": [ + 0.501, + 0.088, + 0.892, + 0.309 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.318, + 0.895, + 0.409 + ], + "angle": 0, + "content": "Figure 5: Visualization of the video in SSV2 validation set. We present our motion guided mask maps and the reconstructed images. From top to bottom, the original images, the x-direction flows, the y-direction flows, the motion guided mask maps, the masked images and the reconstructed images." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.439, + 0.894, + 0.484 + ], + "angle": 0, + "content": "variations between the two. Fig. 4 showcases the 29 categories with the most pronounced differences in classification accuracy between MGMAE and VideoMAE." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.508, + 0.894, + 0.719 + ], + "angle": 0, + "content": "MGMAE: a more effective video representation learner. MGMAE benefits greatly from the harder task constructed by our motion guided masking strategy. On the one hand, the model has to encode the relationship between visible and invisible tokens harder, which can better guide the model training. On the other hand, the suppression of information leakage may well reduce the overfitting risk of the pretraining, and thus the model can be pre-trained much longer. As shown in Tab. 3, MGMAE consistently maintains an obvious fine-tuning performance gap with VideoMAE on the motion-centric SSV2 dataset (1.4% at 800 epochs and 1.5% at 2400 epochs) and also has some improvement on the scene-centric Kinetics-400 dataset (1.2% at 800 epochs and 0.3% at 1600 epochs)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.743, + 0.894, + 0.818 + ], + "angle": 0, + "content": "Visualization. We randomly seletec a video clip in SSV2 validation set and show its reconstruction example in Fig. 5. We can see that the mask map changes with object movements, which makes it more difficult for the model to reconstruct the original video." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.832, + 0.887, + 0.847 + ], + "angle": 0, + "content": "4.4. Comparison with the state-of-the-art methods" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.856, + 0.894, + 0.9 + ], + "angle": 0, + "content": "We compare our approach with the previous state-of-the-art methods on the Kinetics-400 and Something-Something V2 datasets. The results are shown in Table 5 and Table 4." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13500" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.162, + 0.088, + 0.805, + 0.346 + ], + "angle": 0, + "content": "
MethodBackbonePre-train dataFramesGFLOPsParamAcc@1Acc@5
TEINetEn[24]ResNet50×28+1699×10×35066.5N/A
TANetEn[26]ResNet50×2ImageNet-1K8+1699×2×35166.090.1
TDEN[43]ResNet101×28+16198×1×38869.692.2
SlowFast [15]ResNet101Kinetics-4008+32106×1×35363.187.6
MViTv1 [13]MViTv1-B64455×1×33767.790.9
TimeSformer [5]ViT-BImageNet-21K8196×1×312159.5N/A
TimeSformer [5]ViT-L645549×1×343062.4N/A
ViViT FE [1]ViT-LIN-21K+K40032995×4×3N/A65.989.9
Motionformer [28]ViT-B16370×1×310966.590.1
Motionformer [28]ViT-L321185×1×338268.191.2
Video Swin [25]Swin-B32321×1×38869.692.7
VIMPAC [32]ViT-LHowTo100M+DALLE w/o label10N/A×10×330768.1N/A
BEVT [45]Swin-BIN-1K+K400+DALLE w/o label32321×1×38870.6N/A
MAE-ST1600e [14]ViT-LKinetics-400 w/o label16597×1×330572.193.9
MaskFeat↑312 [48]MViT-LKinetics-600402828×1×321875.095.0
VideoMAE800e [35]ViT-BSSV2 w/o label16180×2×38769.692.0
VideoMAE2400e [35]ViT-B16180×2×38770.892.4
MGMAE800eViT-BSSV2 w/o label16180×2×38771.093.1
MGMAE2400eViT-B16180×2×38772.393.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.35, + 0.892, + 0.366 + ], + "angle": 0, + "content": "Table 4: Comparison on the Something-Something V2 dataset. We only list the results obtained with the similar backbones." + }, + { + "type": "table", + "bbox": [ + 0.179, + 0.376, + 0.79, + 0.608 + ], + "angle": 0, + "content": "
MethodBackbonePre-train dataFramesGFLOPsParamAcc@1Acc@5
NL I3D [47]ResNet101ImageNet-1K128359×10×36277.393.3
TANet [26]ResNet15216242×4×35979.394.1
TDEN[43]ResNet1018+16198×10×38879.494.4
TimeSformer [5]ViT-LImageNet-21K968353×1×343080.794.7
ViViT FE [1]ViT-L1283980×1×3N/A81.793.8
Motionformer [28]ViT-L321185×10×338280.294.8
Video Swin [25]Swin-B32282×4×38882.795.5
VIMPAC [32]ViT-LHowTo100M+DALLE w/o label10N/A×10×330777.4N/A
BEVT [45]Swin-BIN-1K+DALLE w/o label32282×4×38880.6N/A
ip-CSN [37]ResNet152None32109×10×33377.892.8
SlowFast [15]R101+NL16+64234×10×36079.893.9
MViTv1 [13]MViTv1-B32170×5×13780.294.4
MAE-ST1600e [14]ViT-BKinetics-400 w/o label16180×7×38781.394.9
VideoMAE800e [35]ViT-B16180×5×38780.094.4
VideoMAE1600e [35]ViT-B16180×5×38781.595.1
MGMAE800eViT-BKinetics-400 w/o label16180×5×38781.294.9
MGMAE1600eViT-B16180×5×38781.895.0
" + }, + { + "type": "table_caption", + "bbox": [ + 0.113, + 0.617, + 0.855, + 0.632 + ], + "angle": 0, + "content": "Table 5: Comparison on the Kinetics-400 dataset. We only list the results obtained with the similar backbones." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.649, + 0.472, + 0.816 + ], + "angle": 0, + "content": "For a fair comparison, we mainly list the results with similar computational cost. On the Something-Something V2 dataset, our MGMAE with ViT-B backbone achieves a performance of \\(72.3\\%\\) when trained for 2400 epochs, which outperforms the original VideoMAE by \\(1.5\\%\\). On the Kinetics-400 dataset, our MGMAE obtains slightly better performance than the original VideoMAE. The small performance improvement might be ascribed to the fact that Kinetics-400 is a scene-centric action recognition benchmark and motion information is less important compared with the Something-Something dataset." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.83, + 0.196, + 0.845 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.472, + 0.903 + ], + "angle": 0, + "content": "In this paper, we have proposed the Motion Guided Masked Autoencoders (MGMAE), which adapts the motion guided masking strategy to dynamically sample the" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.649, + 0.895, + 0.771 + ], + "angle": 0, + "content": "unmasked visible tokens under the guidance of flows, thus suppressing information leakage to build a more challenging task for masked video pre-training. Experiments have shown that MGMAE has good performance and maintains a high-performance advantage over the previous methods under fair comparison. In addition, our strategy also reduces the risk of pre-training overfitting, which allows the model to benefit from longer pre-training." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.897, + 0.903 + ], + "angle": 0, + "content": "Acknowledgements. This work is supported by the National Key R&D Program of China (No. 2022ZD0160900, No.2022ZD0160100), the National Natural Science Foundation of China (No. 62076119, No. 61921006), Shanghai Committee of Science and Technology (Grant No. 21DZ1100100), and Collaborative Innovation Center of Novel Software Technology and Industrialization." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "13501" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.115, + 0.47, + 0.17 + ], + "angle": 0, + "content": "[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In IEEE/CVF International Conference on Computer Vision, 2021. 1, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.171, + 0.472, + 0.254 + ], + "angle": 0, + "content": "[2] Wele Gedara Chaminda Bandara, Naman Patel, Ali Gholami, Mehdi Nikkhah, Motilal Agrawal, and Vishal M Patel. Adamae: Adaptive masking for efficient spatiotemporal learning with masked autoencoders. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14507-14517, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.256, + 0.471, + 0.297 + ], + "angle": 0, + "content": "[3] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. BEit: BERT pre-training of image transformers. In International Conference on Learning Representations, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.298, + 0.471, + 0.366 + ], + "angle": 0, + "content": "[4] Wenbo Bao, Wei-Sheng Lai, Chao Ma, Xiaoyun Zhang, Zhiyong Gao, and Ming-Hsuan Yang. Depth-aware video frame interpolation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3703-3712, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.368, + 0.471, + 0.41 + ], + "angle": 0, + "content": "[5] Gedas Bertasius, Heng Wang, and Lorenzo Torresani. Is space-time attention all you need for video understanding? In International Conference on Machine Learning, 2021. 1, 3, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.411, + 0.471, + 0.479 + ], + "angle": 0, + "content": "[6] Kelvin CK Chan, Shangchen Zhou, Xiangyu Xu, and Chen Change Loy. Basicvsr++: Improving video superresolution with enhanced propagation and alignment. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5972-5981, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.481, + 0.471, + 0.535 + ], + "angle": 0, + "content": "[7] Mark Chen, Alec Radford, Rewon Child, Jeffrey Wu, Heewoo Jun, David Luan, and Ilya Sutskever. Generative pretraining from pixels. In International Conference on Machine Learning, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.537, + 0.471, + 0.592 + ], + "angle": 0, + "content": "[8] Yutao Cui, Cheng Jiang, Limin Wang, and Gangshan Wu. Mixformer: End-to-end tracking with iterative mixed attention. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.593, + 0.471, + 0.662 + ], + "angle": 0, + "content": "[9] Navneet Dalal and Bill Triggs. Histograms of oriented gradients for human detection. In 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR 2005), 20-26 June 2005, San Diego, CA, USA, pages 886-893. IEEE Computer Society, 2005. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.663, + 0.471, + 0.704 + ], + "angle": 0, + "content": "[10] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In CVPR, pages 248–255. IEEE Computer Society, 2009. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.705, + 0.471, + 0.761 + ], + "angle": 0, + "content": "[11] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In North American Chapter of the Association for Computational Linguistics, 2019. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.762, + 0.471, + 0.844 + ], + "angle": 0, + "content": "[12] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2021. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.845, + 0.471, + 0.901 + ], + "angle": 0, + "content": "[13] Haoqi Fan, Bo Xiong, Karttikeya Mangalam, Yanghao Li, Zhicheng Yan, Jitendra Malik, and Christoph Feichtenhofer. Multiscale vision transformers. In IEEE/CVF International Conference on Computer Vision, 2021. 9" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.115, + 0.472, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.147 + ], + "angle": 0, + "content": "[14] Christoph Feichtenhofer, Haoqi Fan, Yanghao Li, and Kaiming He. Masked autoencoders as spatiotemporal learners. In Advances in Neural Information Processing Systems, 2022. 1, 2, 4, 5, 7, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.15, + 0.894, + 0.204 + ], + "angle": 0, + "content": "[15] Christoph Feichtenhofer, Haoqi Fan, Jitendra Malik, and Kaiming He. Slowfast networks for video recognition. In IEEE/CVF International Conference on Computer Vision, 2019. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.206, + 0.894, + 0.316 + ], + "angle": 0, + "content": "[16] Raghav Goyal, Samira Ebrahimi Kahou, Vincent Michalski, Joanna Materzynska, Susanne Westphal, Heuna Kim, Valentin Haenel, Ingo Fründ, Peter Yianilos, Moritz Mueller-Freitag, Florian Hoppe, Christian Thurau, Ingo Bax, and Roland Memisevic. The \"something something\" video database for learning and evaluating visual common sense. In IEEE/CVF International Conference on Computer Vision, 2017. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.318, + 0.893, + 0.374 + ], + "angle": 0, + "content": "[17] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.376, + 0.893, + 0.431 + ], + "angle": 0, + "content": "[18] Zhewei Huang, Tianyuan Zhang, Wen Heng, Boxin Shi, and Shuchang Zhou. Rife: Real-time intermediate flow estimation for video frame interpolation. arXiv preprint arXiv:2011.06294, 2020.3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.433, + 0.893, + 0.488 + ], + "angle": 0, + "content": "[19] Sunil Hwang, Jaehong Yoon, Youngwan Lee, and Sung Ju Hwang. Efficient video representation learning via masked video modeling with motion-centric token selection. arXiv preprint arXiv:2211.10636, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.49, + 0.893, + 0.559 + ], + "angle": 0, + "content": "[20] Will Kay, Joao Carreira, Karen Simonyan, Brian Zhang, Chloe Hillier, Sudheendra Vijayanarasimhan, Fabio Viola, Tim Green, Trevor Back, Paul Natsev, Mustafa Suleyman, and Andrew Zisserman. The kinetics human action video dataset. arXiv preprint arXiv:1705.06950, 2017. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.561, + 0.894, + 0.63 + ], + "angle": 0, + "content": "[21] Heeseung Kwon, Manjin Kim, Suha Kwak, and Minsu Cho. Motionsqueeze: Neural motion feature learning for video understanding. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XVI 16, pages 345-362. Springer, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.632, + 0.893, + 0.673 + ], + "angle": 0, + "content": "[22] Yan Li, Bin Ji, Xintian Shi, Jianguo Zhang, Bin Kang, and Limin Wang. TEA: temporal excitation and aggregation for action recognition. In CVPR, pages 906-915, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.675, + 0.893, + 0.743 + ], + "angle": 0, + "content": "[23] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In IEEE/CVF International Conference on Computer Vision, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.745, + 0.894, + 0.814 + ], + "angle": 0, + "content": "[24] Zhaoyang Liu, Donghao Luo, Yabiao Wang, Limin Wang, Ying Tai, Chengjie Wang, Jilin Li, Feiyue Huang, and Tong Lu. TEINet: Towards an efficient architecture for video recognition. In Proceedings of the AAAI Conference on Artificial Intelligence, 2020. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.816, + 0.893, + 0.871 + ], + "angle": 0, + "content": "[25] Ze Liu, Jia Ning, Yue Cao, Yixuan Wei, Zheng Zhang, Stephen Lin, and Han Hu. Video swim transformer. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.873, + 0.893, + 0.901 + ], + "angle": 0, + "content": "[26] Zhaoyang Liu, Limin Wang, Wayne Wu, Chen Qian, and Tong Lu. Tam: Temporal adaptive module for video recognition." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "13502" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.472, + 0.119 + ], + "angle": 0, + "content": "In IEEE/CVF International Conference on Computer Vision, 2021. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.121, + 0.472, + 0.176 + ], + "angle": 0, + "content": "[27] Deepak Pathak, Philipp Krahenbuhl, Jeff Donahue, Trevor Darrell, and Alexei A. Efros. Context encoders: Feature learning by inpainting. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.177, + 0.472, + 0.245 + ], + "angle": 0, + "content": "[28] Mandela Patrick, Dylan Campbell, Yuki M. Asano, Ishaan Misra, Florian Metze, Christoph Feichtenhofer, Andrea Vedaldi, and João F. Henriques. Keeping your eye on the ball: Trajectory attention in video transformers. In NeurIPS, pages 12493-12506, 2021. 3, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.247, + 0.472, + 0.3 + ], + "angle": 0, + "content": "[29] Zhiwu Qing, Shiwei Zhang, Ziyuan Huang, Xiang Wang, Yuehuan Wang, Yiliang Lv, Changxin Gao, and Nong Sang. Mar: Masked autoencoders for efficient action recognition. IEEE Transactions on Multimedia, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.302, + 0.472, + 0.344 + ], + "angle": 0, + "content": "[30] Alec Radford, Jeff Wu, Rewon Child, David Luan, Dario Amodei, and Ilya Sutskever. Language models are unsupervised multitask learners. OpenAI blog, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.345, + 0.472, + 0.385 + ], + "angle": 0, + "content": "[31] Karen Simonyan and Andrew Zisserman. Two-stream convolutional networks for action recognition in videos. Advances in Neural Information Processing Systems, 2014. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.386, + 0.472, + 0.439 + ], + "angle": 0, + "content": "[32] Hao Tan, Jie Lei, Thomas Wolf, and Mohit Bansal. Vimpac: Video pre-training via masked token prediction and contrastive learning. arXiv preprint arXiv:2106.11250, 2021. 2, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.442, + 0.472, + 0.496 + ], + "angle": 0, + "content": "[33] Jing Tan, Jiaqi Tang, Limin Wang, and Gangshan Wu. Relaxed transformer decoders for direct action proposal generation. In IEEE/CVF International Conference on Computer Vision, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.498, + 0.472, + 0.539 + ], + "angle": 0, + "content": "[34] Zachary Teed and Jia Deng. Raft: Recurrent all-pairs field transforms for optical flow. In European conference on computer vision, pages 402-419. Springer, 2020. 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.54, + 0.472, + 0.594 + ], + "angle": 0, + "content": "[35] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. Video-MAE: Masked autoencoders are data-efficient learners for self-supervised video pre-training. In Advances in Neural Information Processing Systems, 2022. 1, 2, 4, 5, 6, 7, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.596, + 0.472, + 0.663 + ], + "angle": 0, + "content": "[36] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Hervé Jégou. Training data-efficient image transformers & distillation through attention. In International Conference on Machine Learning, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.665, + 0.472, + 0.719 + ], + "angle": 0, + "content": "[37] Du Tran, Heng Wang, Matt Feiszli, and Lorenzo Torresani. Video classification with channel-separated convolutional networks. In IEEE/CVF International Conference on Computer Vision, 2019. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.721, + 0.472, + 0.776 + ], + "angle": 0, + "content": "[38] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Advances in Neural Information Processing Systems, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.777, + 0.472, + 0.831 + ], + "angle": 0, + "content": "[39] Pascal Vincent, Hugo Larochelle, Yoshua Bengio, and Pierre-Antoine Manzagol. Extracting and composing robust features with denoising autoencoders. In International Conference on Machine Learning, 2008. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.832, + 0.472, + 0.901 + ], + "angle": 0, + "content": "[40] Pascal Vincent, Hugo Larochelle, Isabelle Lajoie, Yoshua Bengio, and Pierre-Antoine Manzagol. Stacked denoising autoencoders: Learning useful representations in a deep network with a local denoising criterion. Journal of Machine Learning Research, 2010. 2" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.472, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.162 + ], + "angle": 0, + "content": "[41] Limin Wang, Bingkun Huang, Zhiyu Zhao, Zhan Tong, Yinan He, Yi Wang, Yali Wang, and Yu Qiao. Videomae v2: Scaling video masked autoencoders with dual masking. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14549-14560, 2023. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.164, + 0.894, + 0.233 + ], + "angle": 0, + "content": "[42] Limin Wang, Yu Qiao, and Xiaou Tang. Action recognition with trajectory-pooled deep-convolutional descriptors. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2015, Boston, MA, USA, June 7-12, 2015, pages 4305-4314. IEEE Computer Society, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.235, + 0.894, + 0.29 + ], + "angle": 0, + "content": "[43] Limin Wang, Zhan Tong, Bin Ji, and Gangshan Wu. TDN: Temporal difference networks for efficient action recognition. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. 3, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.292, + 0.893, + 0.347 + ], + "angle": 0, + "content": "[44] Limin Wang, Yuanjun Xiong, Zhe Wang, Yu Qiao, Dahua Lin, Xiaou Tang, and Luc Van Gool. Temporal segment networks for action recognition in videos. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.349, + 0.894, + 0.417 + ], + "angle": 0, + "content": "[45] Rui Wang, Dongdong Chen, Zuxuan Wu, Yinpeng Chen, Xiyang Dai, Mengchen Liu, Yu-Gang Jiang, Luowei Zhou, and Lu Yuan. Bevt: Bert pretraining of video transformers. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.42, + 0.894, + 0.488 + ], + "angle": 0, + "content": "[46] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In IEEE/CVF International Conference on Computer Vision, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.49, + 0.893, + 0.532 + ], + "angle": 0, + "content": "[47] Xiaolong Wang, Ross Girshick, Abhinav Gupta, and Kaiming He. Non-local neural networks. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2018. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.534, + 0.894, + 0.601 + ], + "angle": 0, + "content": "[48] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.604, + 0.894, + 0.671 + ], + "angle": 0, + "content": "[49] Enze Xie, Wenhai Wang, Zhiding Yu, Anima Anandkumar, Jose M Alvarez, and Ping Luo. Segformer: Simple and efficient design for semantic segmentation with transformers. In Advances in Neural Information Processing Systems, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.675, + 0.894, + 0.743 + ], + "angle": 0, + "content": "[50] Zhenda Xie, Zheng Zhang, Yue Cao, Yutong Lin, Jianmin Bao, Zhuliang Yao, Qi Dai, and Han Hu. Simmim: A simple framework for masked image modeling. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.746, + 0.894, + 0.8 + ], + "angle": 0, + "content": "[51] Xitong Yang, Xiaodong Yang, Sifei Liu, Deqing Sun, Larry Davis, and Jan Kautz. Hierarchical contrastive motion learning for video action recognition. arXiv preprint arXiv:2007.10321, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.803, + 0.894, + 0.871 + ], + "angle": 0, + "content": "[52] Li Yuan, Yunpeng Chen, Tao Wang, Weihao Yu, Yujun Shi, Francis EH Tay, Jiashi Feng, and Shuicheng Yan. Token-to-token vit: Training vision transformers from scratch onImagenet. In IEEE/CVF International Conference on Computer Vision, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.874, + 0.894, + 0.901 + ], + "angle": 0, + "content": "[53] Christopher Zach, Thomas Pock, and Horst Bischof. A duality based approach for realtime tv-1 optical flow. In" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13503" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.134 + ], + "angle": 0, + "content": "Pattern Recognition: 29th DAGM Symposium, Heidelberg, Germany, September 12-14, 2007. Proceedings 29, pages 214-223. Springer, 2007. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.472, + 0.175 + ], + "angle": 0, + "content": "[54] Chen-Lin Zhang, Jianxin Wu, and Yin Li. Actionformer: Localizing moments of actions with transformers. CoRR, abs/2202.07925, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.179, + 0.472, + 0.26 + ], + "angle": 0, + "content": "[55] Guozhen Zhang, Yuhan Zhu, Haonan Wang, Youxin Chen, Gangshan Wu, and Limin Wang. Extracting motion and appearance via inter-frame attention for efficient video frame interpolation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5682-5692, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.263, + 0.471, + 0.303 + ], + "angle": 0, + "content": "[56] Kaidong Zhang, Jingjing Fu, and Dong Liu. Flow-guided transformer for video inpainting. In European Conference on Computer Vision, pages 74-90. Springer, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.306, + 0.472, + 0.414 + ], + "angle": 0, + "content": "[57] Yue Zhao, Yuanjun Xiong, and Dahua Lin. Trajectory convolution for action recognition. In Samy Bengio, Hanna M. Wallach, Hugo Larochelle, Kristen Grauman, Nicolò Cesà-Bianchi, and Roman Garnett, editors, Advances in Neural Information Processing Systems 31: Annual Conference on Neural Information Processing Systems 2018, NeurIPS 2018, December 3-8, 2018, Montréal, Canada, pages 2208-2219, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.418, + 0.472, + 0.485 + ], + "angle": 0, + "content": "[58] Yuan Zhi, Zhan Tong, Limin Wang, and Gangshan Wu. Mgsampler: An explainable sampling strategy for video action recognition. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 1493-1502. IEEE, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.488, + 0.472, + 0.541 + ], + "angle": 0, + "content": "[59] Daquan Zhou, Bingyi Kang, Xiaojie Jin, Linjie Yang, Xiaochen Lian, Qibin Hou, and Jiashi Feng. Deepvit: Towards deeper vision transformer. arXiv preprint arXiv:2103.11886, 2021. 1" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.472, + 0.541 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "13504" + } + ] +] \ No newline at end of file diff --git a/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/913ed268-24e1-487c-b23b-995e3fca2c86_origin.pdf b/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/913ed268-24e1-487c-b23b-995e3fca2c86_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..23a40da191cbcbd0925582ce1ba7657fa61640c0 --- /dev/null +++ b/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/913ed268-24e1-487c-b23b-995e3fca2c86_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:42e01d2b46a7dafac1549c0adf32b4df902e5c07fed90e9c1a68445b3a5cbdb0 +size 2065131 diff --git a/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/full.md b/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/full.md new file mode 100644 index 0000000000000000000000000000000000000000..a4c59471fe3eeccde5d56b1fcaa356763709bb00 --- /dev/null +++ b/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/full.md @@ -0,0 +1,304 @@ +# MGMAE: Motion Guided Masking for Video Masked Autoencoding + +Bingkun Huang $^{1,2}$ Zhiyu Zhao $^{1,2}$ Guozhen Zhang $^{1}$ Yu Qiao $^{2}$ Limin Wang $^{1,2,\text{图}}$ $^{1}$ State Key Laboratory for Novel Software Technology, Nanjing University $^{2}$ Shanghai AI Lab https://github.com/MCG-NJU/MGMAE + +# Abstract + +Masked autoencoding has shown excellent performance on self-supervised video representation learning. Temporal redundancy has led to a high masking ratio and customized masking strategy in VideoMAE. In this paper, we aim to further improve the performance of video masked autoencoding by introducing a motion guided masking strategy. Our key insight is that motion is a general and unique prior in video, which should be taken into account during masked pretraining. Our motion guided masking explicitly incorporates motion information to build temporal consistent masking volume. Based on this masking volume, we can track the unmasked tokens in time and sample a set of temporal consistent cubes from videos. These temporal aligned unmasked tokens will further relieve the information leakage issue in time and encourage the MGMAE to learn more useful structure information. We implement our MGMAE with an online efficient optical flow estimator and backward masking map warping strategy. We perform experiments on the datasets of Something-Something V2 and Kinetics-400, demonstrating the superior performance of our MGMAE to the original VideoMAE. In addition, we provide the visualization analysis to illustrate that our MGMAE can sample temporal consistent cubes in a motion-adaptive manner for more effective video pre-training. + +# 1. Introduction + +Attention-based Transformer [38] has witnessed great success in computer vision since the introduction of Vision Transformer (ViT) [12]. It has been applied for a variety of vision tasks and obtains state-of-the-art performance, such as image classification [36, 59, 52], object detection [23, 46], semantic segmentation [49], and object tracking [8]. Thanks to this high performance, ViT models have been also applied to the video domain for action recognition [5, 1] and detection [33, 54]. However, the high capacity of Transformer often demands pre-training on a large-scale dataset to reduce the over-fitting risk of subsequent fine + +![](images/d4dab8bfd4010748a06b3de6e48e1ee025825d8792f44d5a49846a90d466612f.jpg) + +![](images/a1f20a198bd90758e6c3ee15b54d130e39e5d2ae73f60a40e39f39d400530110.jpg) +(a) original video clip +(c) random masking +Figure 1: Comparison of different masking strategies. Masked autoencoding [11, 17] has been explored in video domain for self-supervised pre-training by employing different masking strategies: random masking [14] and tube masking [35]. We propose to track masking maps under the guidance of motion information (termed as motion guided masking). Our resulting MGMAE can build a more challenging and meaningful task for video pre-training. + +![](images/ddb52fbe1b47eebe164b05caf6541ce36ee9c4a233a060042c877eb5d81fa49b.jpg) + +![](images/2415c759021d623aeab12bdfef0c56a17bbfee998738cbe4ca04de3213372218.jpg) +(b) tube masking +(d) motion guided masking + +tuning. Therefore, an effective pretraining strategy of ViT is particularly important for obtaining excellent performance in the video domain due to the smaller video dataset. + +The early video transformers [1, 5] often rely on the pre-training of image-based transformer derived from the large-scale image dataset [10]. This pre-training scheme makes the learnt video model to be naturally biased by image-based ViTs. Recently, masked autoencoding (MAE) [35, 14, 41] has been explored for pre-training video transformer on the video dataset due to its simplicity and promising result in image domain [17]. However, unlike the image, video data is equipped with an extra time dimension and exhibits the unique property of temporal redundancy and correlation. This property requires some customized designs on video masked autoencoder compared with image-based MAE. For example, VideoMAE and MAE-ST both propose to use an extremely high masking ratio in video masked autoencoder pre-training to improve its performance. In addition, VideoMAE devises a tube masking strategy of dropping tokens at the same position across frames to further relieve the information leakage in time. This tube masking + +approach, though straightforward, makes the assumption of no or small motion occurring between adjacent frames. Such an assumption might be not true for some scenarios with high-speed motion. + +Based on the above analysis, in this paper, we aim to propose a new masking strategy for improving video masked autoencoder pre-training, by explicitly using motion information to reduce information leakage in time. Specifically, we devise the Motion Guided Masking in the video masked encoder processing and the resulted masked autoencoder is termed as MGMAE. Motion is general prior information contained by video. The optical flow representation explicitly encodes the movement of each pixel from the current frame to the next one. We propose to use this optical flow to align masking maps between adjacent frames to build consistent masking volumes across time. The consistent masking volumes enable to build a more challenging reconstruction task by enforcing only a small set of cube tracks visible to the encoder. Hopefully, this motion guided masking can further relieve the risk of information leakage in time and encourage learning more meaningful visual representations. + +More specifically, we use an online and lightweight optical flow estimator (RAFT [34]) to capture motion information, which could be seamlessly integrated into the existing VideoMAE framework. To build the temporally consistent masking volume, we first randomly generate an initial masking map at the base frame. Then, we use the estimated optical flow to warp the initial masking map to adjacent frames. With multiple warping operations, we build the temporal consistent masking volume for all frames in the video. Finally, based on this masking volume, we sample a set of visible tokens to MAE encoders with top-k selection based on a frame-wise manner. The same autoencoding process with the original VideoMAE is applied to these sampled tokens for video pretraining. With this simple motion guided masking, we are able to further increase the difficulty of video pre-training task and thus lead to a better pre-trained model for subsequent fine-tuning. + +We mainly verify the effectiveness of the proposed MGMAE on the datasets of Something-Something V2 [16] and Kinetics-400 [20] by comparing them with the original tube masking in VideoMAE. The results demonstrate that MGMAE pre-training can result in more powerful video foundation models with higher fine-tuning accuracy on the downstream tasks. In particular, on the motion-centric benchmark of Something-Something, the improvement of MGMAE is more evident, implying that our motion guided masking is adaptive to motion variations and can better capture temporal structure information for pre-training. We hope our findings can inspire some specific and unique designs in video masked autoencoding with respect to image counterparts. + +# 2. Related Work + +Masked Visual Modeling. Masked autoencoder is a long-standing unsupervised learning framework in computer vision. The early work presented general form of denoising autoencoder [40, 39] for learning representation by reconstructing the clean signal from the noisy inputs. The other work [27] also treated masking modeling as inpainting missing regions from the surrounding context by using convolutions. Inspired by the great success of masked language modeling [11], some works also attempted to apply this pretraining paradigm to the vision domain for self-supervised pre-training. For example, iGPT [7] followed the GPT work [30] in NLP and processed a sequence of pixels for casual prediction of the next pixels. The original ViT [12] used the masked token prediction as a self-supervised training step on large-scale image datasets but failed to obtain impressive results. Recently, several interesting works have obtained a great breakthrough in self-supervised image pre-training by using masked image modeling, such as BEiT [3], SimMIM [50], and MAE [17]. BEiT [3] directly followed the BERT framework and proposed to predict the discrete token label for masked patches, by requiring an explicit tokenizer to build the token dictionary. SimMIM [50] and MAE [17] shared the same design of directly predicting the pixels of masked patches without any tokenizer design. Furthermore, MAE [17] devised an asymmetric encoder-decoder architecture to speed up the masked image pre-training. + +Since the great success in masked image modeling, some works have tried to extend this new pre-training paradigm to the video domain for self-supervised video pre-training. BEVT [45] and VIMPAC [32] proposed to learn video representation by predicting discrete visual tokens in a similar way to BEiT. However, their performance improvement in video action recognition is limited. MaskFeat [48] used the HOG features [9] as the reconstructed targets of masked patches and achieved excellent performance on the video recognition with a multi-scale vision transformer. VideoMAE [35] and MAE-ST [14] extended the image MAE to the video domain for representation learning with vanilla vision transformer. They both proposed to use an extremely high masking ratio to deal with video data redundancy. Meanwhile, VideoMAE [35] used the tube masking to further increase the difficulty of reconstruction. Several works building upon VideoMAE have emerged. For instance, MAR [29] reduced both training and inference costs by introducing running cell masking. Meanwhile, VideoMAE V2 [41] proposes a dual masking strategy to decrease pre-training overhead, and by expanding both the model size and dataset, it further explores the scalability of VideoMAE. Our proposed motion guided masking aims to improve the performance of VideoMAE by building a more challenging masking and reconstruction task. In contrast to the original VideoMAE, our MGMAE explicitly use the optical flow to align the masking maps + +across frames and generate the temporal consistent masking volume to sample a set of visible tokens. + +Motion Guided Modeling. Motion information, such as optical flow, is a general prior information in videos and represents the unique characteristics distinct from images. Optical flow has been widely introduced to provide a strong prior in both low-level and high-level vision tasks on video. For low-level video tasks, the motion is often used to align the information of auxiliary frames to the corresponding region of the target frame. In the case of video super-resolution, BasicVSR++ [6] uses optical flow to enhance the appearance of low-resolution frames by transferring features from neighbor frames. For video inpainting, Zhang et al. [56] exploits the motion difference extracted by optical flows to instruct the attention retrieval in transformer for high-fidelity video inpainting. As for video frame interpolation, mainstream methods leverage optical flow directly on the image to synthesize the intermediate frame, such as DAIN [4] and RIFE [18], while Zhang et al. [55] introduces a unified operation utilizing inter-frame attention to concurrently extract motion and appearance information, and blends a hybrid CNN and Transformer design for efficiency and fine-grained detail preservation. For high-level video tasks, the optical flow is directly used as a data modality as network input for action recognition [44, 31]. TDD [42] utilized motion trajectories to pool deep convolutional features for action recognition. Trajectory Convolution [57] incorporated the motion information into temporal convolutional kernel design. MSNet [21] proposes a pluggable MotionSqueeze module to generate motion information across frames. VideoMS [19] generates mask maps by calculating the feature difference after patch embedding, making an attempt at dynamically adjusting mask positions. AdaMAE [2] introduces an end-to-end trainable adaptive masking strategy for MAEs, leveraging an auxiliary sampling network to prioritize tokens from high spatiotemporal information regions. Yang et al. [51] leverage hierarchical motion information to improve the extracted video features. MotionFormer [28] employed the trajectory for attention computation in the video transformer. TEA [22] and TDN [43] used RGB difference to approximate the motion information and incorporate this information into the video CNN backbone design. MGSampler [58] explored the motion information to select a subset of representative frames for efficient video action recognition. Our MGMAE shares the same spirit with these motion guided modeling works. We focus on employing motion information as a cue to generate masking maps for masked video pre-training. + +# 3. Method + +In this section, we first revisit the pre-training paradigm of VideoMAE to well introduce our MGMAE in Sec. 3.1. + +Then we present the details of motion guided masking map generation in Sec. 3.2. Finally, we describe the MGMAE pretraining under temporal consistent masking maps in Sec. 3.3. + +# 3.1. VideoMAE revisited + +VideoMAE is a simple masked video autoencoder with an asymmetric encoder-decoder architecture with an extra cube embedding to handle the input sampled frames. Next, we briefly revisit its implementation detail. + +Cube Embedding. VideoMAE divides the input video clip $\mathbf{I}$ of size $T\times 3\times H\times W$ into non-overlapping cubes $\mathbf{C} = \{\mathbf{C}_i\mid \mathbf{C}_i\in \mathbb{R}^{2\times 16\times 16\times 3}\}_{i = 1}^N$ , where $N = \frac{T}{2}\times \frac{H}{16}\times \frac{W}{16}$ is the number of cubes. Then apply cube embedding on the cubes to produce the video tokens $\mathbf{T} = \{\mathbf{T}_i\mid \mathbf{T}_i\in \mathbb{R}^D\}_{i = 1}^N$ , where $T_{i}$ represents the cube embedding with positional encoding, and $D$ is the channel. + +Masking Strategy. VideoMAE uses the tube masking strategy with an extremely high masking ratio $\rho$ (i.e. $90\%$ ), which samples the same spatial positions across all frames of the input video clip. Specifically, VideoMAE first generate a $\frac{H}{16} \times \frac{W}{16}$ binary mask map $\mathbf{M}'$ where 0 represents unmasked and 1 represents masked. Then it replicates it in temporal dimension and then flattens it to produce the token-level mask map $\mathbf{M}$ whose size is $N$ for the input video clip. We denote $\mathbb{M}$ as the masking maps. + +Encoder. The encoder is a vanilla ViT with joint space-time attention [5]. For computation efficiency, only the unmasked visible tokens $\mathbf{T}^v = \{\mathbf{T}_i\}_{i\notin \mathbb{M}}$ added with the fixed positional embedding are fed into the encoder to obtain the latent features $\mathbf{Z}$ of size $N_v\times D$ , where $N_{v} = \lfloor (1 - \rho)N\rfloor$ is the total number of the unmasked visible tokens. + +Decoder. The decoder is a narrower and shallower ViT than the encoder. It takes the concatenated token sequences as input, which is formed by the concatenation between the latent features $\mathbf{Z}$ and the learnable [MASK] tokens with the fixed position embedding added, to reconstruct the normalized video cubes $\hat{\mathbf{C}} = \left\{\hat{\mathbf{C}}_i \mid \hat{\mathbf{C}}_i \in \mathbb{R}^{2 \times 16 \times 16 \times 3}\right\}_{i=1}^N$ . + +Loss. The pre-training object is to minimize the Mean Square Error Loss between the normalized $\mathbf{C}$ and $\hat{\mathbf{C}}$ on the masked positions, i.e. $\frac{1}{\rho N} \sum_{i \in \mathbb{M}} \left| \hat{\mathbf{C}}_i - \mathrm{norm}(\mathbf{C}_i) \right|^2$ . + +After the pre-training, the encoder will be used as the backbone network to fine-tune on the downstream tasks to obtain a specialized model. + +![](images/3cdb054ac6de8fe38e81bf3be96d5041084f8f4dba66d980c38d9ebe40945d87.jpg) +Figure 2: Pipeline of MGMAE. Our MGMAE follows the simple pipeline of masking and reconstruction for video self-supervised pre-training. Our core design is to propose a motion guided masking strategy to generate temporal consistent masking volume. With this masking volume, we track the visible cubes and attain temporal consistency for masking maps. As a result, we can build a more challenging reconstruction task and encourage extracting more effective representations during masked self-supervised pretraining. + +# 3.2. Motion Guided Masking Map + +Time is a unique characteristic of video and has different properties with the space dimension. When devising masked video autoencoder, we need to carefully take this extra time dimension into account and come up with a customized design. Information leakage in time is an important issue in masked video pre-training. When information leakage occurs, the model can easily reconstruct the masked cubes based on the visible tokens of adjacent frames. In this case, it will greatly reduce the difficulty of the reconstruction task and lead to a pre-trained model with poor fine-tuning performance. A trivial solution to information leakage is to increase the masking ratio. VideoMAE [35] and MAE-ST [14] increase the masking ratio to $90\%$ to greatly increase the difficulty of reconstruction. In addition, VideoMAE makes the small motion assumption and adapts the tube masking strategy, which masks the same spatial position in all frames. However, this small motion prior is not always true for motion-dominated videos. A more reasonable approach is to keep each object in the video clip visible or invisible at all times. To achieve this goal, we propose the motion guided masking strategy to replace the tube masking strategy in VideoMAE. The strategy has two procedures: we first use the optical flow as guidance to generate temporally consistent masking volumes of the input video clip + +and then sample the unmasked visible tokens based on the temporal consistent masking volume. We will detail these two procedures in Sec. 3.2 and Sec. 3.3. + +In general, the procedure for generating the temporal consistent masking volumes has four steps as follows. + +- Step 1: Determine the base frame $\mathbf{I}_b$ , where $b$ is the index of the base frame. +- Step 2: Randomly generate a pixel-level initial mask map $\mathbf{M}_b$ with size $H \times W$ as the mask map of $\mathbf{I}_b$ . +- Step 3: Extract the dense flows $\mathbf{F}$ bidirectionally from the base frame $\mathbf{I}_b$ in the input video clip $\mathbf{I}$ . +- Step 4: Warp the initial masking map $\mathbf{M}_b$ under the guidance of dense flows $\mathbf{F}$ and progressively build the temporal consistent masking volume $\mathbf{M}$ of size $T \times H \times W$ . + +Determine the base frame. By default, we choose the middle frame as the base frame. In motion guided masking, we need to ensure all objects in the base frame remain consistently visible or invisible in all frames of the input clip. Note that objects may (dis)appear over time due to object or camera movement, and warping the masking map under optical flow can result in some holes due to pixels mapped + +out of bounds. So the choice of the base frame may have an impact on the suppression of information leakage. We ablate the choice of the base frame in Sec. 4.2 and the middle frame is the optimal choice. + +Generate the initial mask map. We initialize a pixel-level masking map for the base frame with the distribution of the Gaussian Mixture Model (GMM). We use the masking map to indicate the visible or invisible state of the cubes in the base frame. Previous masking strategies usually adapt a token-level binary initialization, i.e. either all 0 or all 1 within each token of size $2 \times 16 \times 16$ , which actually breaks the continuity of the object surface texture. + +Specifically, we first randomly pick $\hat{N}_v = \left\lfloor (1 - \rho) \times \frac{H}{16} \times \frac{W}{16} \right\rfloor$ tokens whose centers are denoted with $c = \{\vec{c_i} : (c_{i1}, c_{i2})\}_i^{\hat{N}_v}$ . Then we generate 2D Gaussian distributions $\mathcal{N}_i(c_i, \sigma^2)$ centered on the midpoint of each token, where $\sigma$ is the standard deviation and taken as the cube size (16, 16). Thus we will obtain the mixed Gaussian distribution $\mathcal{P}(c, \sigma^2) = \sum_{i}^{\hat{N}_v} \mathcal{N}_i(\vec{c_i}, \sigma^2)$ corresponding to the base frame. And the probability density function of the mixed Gaussian distribution is used to indicate the probability that the cube (token) is visible in the base frame. + +Extract optical flows. We use both online and offline alternative methods to extract optical flow. Online method adapts RAFT [34] (the small version) to estimate the flows of the input video clip. Offline method applies the traditional TVL1 [53] algorithm to extract the dense flows between all adjacent frames in advance. We perform the consistent crop-resize-rescale operations when reading flows. Online and offline methods achieve the similar results. More details see in Sec. 4.2. + +In practice, we only extract the flows $\mathbf{F}$ forward and backward from the base frame $\mathbf{I}_b$ , i.e. + +$$ +\mathbf {F} = \left\{v _ {i \rightarrow i + 1} \right\} _ {i = 1} ^ {b - 1} \cup \left\{v _ {i \rightarrow i - 1} \right\} _ {i = b + 1} ^ {T}, \tag {1} +$$ + +where the flow $v_{i\rightarrow j}$ denotes the flow from $\mathbf{I}_i$ to $\mathbf{I}_j$ . + +Warp masking maps with flows. We utilize the method of backward warping to generate the temporal consistent masking map of the video clip in a progressive manner. Forward warping $\phi_F$ and backward warping $\phi_B$ are two opposite patterns of warping. Both can be effectively employed to construct the masking volume from the initial masking map. Regrettably, forward warping suffers from hole or occlusion problems, that is, no flow vectors may pass to a certain pixel, or there may be multiple flow vectors passing to the same pixel. In contrast, backward warping maps the pixels of a given map one by one to individual locations. It's noteworthy that while backward warping doesn't escape from the issue of holes caused by mapping out of bounds, these holes are + +usually fewer than in forward warping and tend to occur at the boundaries of the map, thus causing less damage to the information distribution. For the holes caused by backward warping, we fill them with the values of $\mathbf{M}_b$ at the same position to simulate the tube masking strategy. + +Formally, given the flows $\mathbf{F}$ and the base frame masking volume $\mathbf{M}_b$ , the mask map $\mathbf{M}_i$ of $\mathbf{I}_i$ can be constructed as + +$$ +\mathbf {M} _ {i} = \left\{\begin{array}{l l}\phi_ {B} \left(\mathbf {M} _ {i + 1}, v _ {i \rightarrow i + 1}\right),&1 \leq i < b\\\mathbf {M} _ {b},&i = b\\\phi_ {B} \left(\mathbf {M} _ {i - 1}, v _ {i \rightarrow i - 1}\right),&b < i \leq T\end{array}. \right. \tag {2} +$$ + +Subsequently, the entire masking volume $\mathbf{M} = \{\mathbf{M}_i\}_{i=1}^T$ of the video clip $\mathbf{I}$ can be constructed by backward warping the flows $\mathbf{F}$ bidirectionally, originating from the base frame mask map $\mathbf{M}_b$ . + +# 3.3. Motion Guided MAE + +We build our MGMAE based on the above motion guided masking map. The temporal consistent masking volume indicates the probability that the corresponding position in the adjacent frame is visible under optical flow tracking. In order to suppress information leakage as much as possible, we sample the video tokens with the highest visible probability along the temporal dimension. Specifically, we first perform average pooling with kernel size $2 \times 16 \times 16$ on the masking volume $\mathbf{M}$ to obtain the token-level masking volume $\mathbf{M}'$ of size $\frac{T}{2} \times \frac{H}{16} \times \frac{W}{16}$ . Then we pick the top- $\hat{N}_v$ locations of each mask map of size $\frac{H}{16} \times \frac{W}{16}$ along the temporal dimension and thus sample $N_v$ corresponding video tokens as the unmasked visible tokens. + +These sampled tokens according to our temporal consistent masking volume are fed into the asymmetric encoder-decoder for autoencoding based pre-training. The resulted pre-training framework is called Motion Guided Masked Autoencoder (MGMAE). The pre-trained model by our MGMAE is applied in the same way with the original Video-MAE for fine-tuning the downstream tasks. + +Discussion. Previous works [35, 14] extended MAE to the video domain. They opted for the random (agnostic) masking and tube (space-only) masking strategies, respectively. Random masking introduces no explicit inductive bias about the video's space and time dimension. It aims to present a unified feature representation learning framework with minimal domain knowledge. We argue that although this idea is simple, time is inherently a distinctive dimension from space. By recognizing this, we could better leverage this prior information for enhanced video masked autoencoding. Tube masking assumes that a large area of the frame contains no or small motion, and thus masking the same position across frames could greatly reduce the information leakage risk. However, for motion-dominated video datasets such as + +Something-Something, this assumption will no longer hold true. Our proposed motion guided masking offers a more general and conceptually simple solution to take temporal correlation into account. It could be viewed as an adaptive video masking strategy and create more challenging yet meaningful tasks in video pre-training. + +# 4. Experiments + +# 4.1. Dataset + +Following the original VideoMAE, we evaluate our MGMAE on Kinetics-400 (K400) [20] and Something-Something V2 (SSV2) [16]. K400 contains about 240k training videos and 20k validation videos from YouTube and the actions in K400 are usually coupled with specific objects or scenes, such as brushing teeth and playing piano. While SSV2 contains about 169k training videos and 25k validation videos, and the categories in SSV2 only care about specific motion patterns (e.g. push, pull). We first pre-train the video transformer with our MGMAE on the corresponding dataset for self-supervised representation learning. Then, we report the fine-tuning performance of pre-trained models on the target datasets for action recognition. In our MGMAE pretraining, we generally follow the setting and implementation of the original VideoMAE [35]. We use the RAFT [34] to extract optical flow due to its efficiency and accuracy in our MGMAE pre-training. The implementation details on our MGMAE could found in the appendix. + +# 4.2. Ablation Studies + +In this subsection, we conduct in-depth ablation experiments on the choice in each step of our motion guided masking strategy. We pre-train the ViT-base model 800 epochs on the SSV2 dataset with 16 80G-A100 GPUs, and then fine-tune the encoder on the SSV2 dataset for action recognition. All models share the same training schedule and report the 2 clips $\times 3$ crops accuracy. + +Choice of the base frame. In this study, we investigate the influence of base frame selection for initial masking generation process. We compare the middle frame as the based frame with either the first or a random frame, and the result is shown in Tab. 1a. It implies the middle frame is the best. + +Warping method with optical flow. We compare two kinds of warping methods to align masking maps across frames as explained in Sec. 3.2. As previously mentioned above, the forward warping often leads to more severe occlusion and hole problems in the masking warping process. On the contrary, backward warping can effectively relieve this issue and ensure a more smooth masking warping. The + +result in Tab. 1b demonstrates that back warping contributes to better performance. + +Sampling strategy of top-k visible tokens. We examine and compare the two sampling strategies to select the visible tokens based on our temporal consistent masking volume. Frame-level strategy samples the top-k locations for each frame independently, while clip-level strategy samples the top-k locations for the entire video jointly. As in Tab. 1c, the frame-level top-k sampling strategy achieves slightly better performance. + +Masking initialization at the base frame. We ablate the choice of generating the initial masking at the base frame as shown in Tab. 1d. The token-level initialization method divides the mask map into $\frac{H}{16} \times \frac{W}{16}$ tokens of size $16 \times 16$ , and randomly sets $90\%$ tokens to 0 (representing masked) and $10\%$ tokens to 1 (representing unmasked). The pixel-level initialization method randomly sets $90\%$ pixels to 0 and $10\%$ pixels to 1. The initialization process of the mixed Gaussian method has been detailed in Sec. 3.2. The result demonstrates that the mixed Gaussian initialization method works the best. + +Hole filling method. We investigate the various methods to handle the holes problem brought by the mapping out of bound in backward warping in Tab. 1e. To determine the real holes caused by warping, we set the 0 in the initial mask map to value $1e - 8$ , and then the locations equal to 0 in new mask maps are treated as the holes. We experiment with 5 methods to fill the holes: Invisible method fills all holes with 0, while Visible method fills all holes with 1. Random method randomly fills the holes to 0 with probability of masking ratio $\rho$ and to 1 with probability of $1 - \rho$ . Previous map method fills holes using the values from the same spatial positions as the last generated mask map. Conversely, Tube method fills the holes with the value from the corresponding positions of the initial mask map, aligning with tube masking principles. We see that the tube method performs the best among all the methods. + +Method of optical flow estimation. We evaluate the effect of different methods of optical flow estimation as shown in Tab. 1f. For the offline method, we use the TVL1 algorithm to extract optical flows in advance and it achieve a comparable accuracy to the online RAFT optical flow. Although VideoMAE is 1.3 times faster to train than MGMAE with RAFT-small (set to 6 testing iterations) to estimate flows, MGMAE has a clear advantage in terms of performance and reducing the risk of overfitting. We find that the offline method is not much faster than the online method because IO (reading optical flow from disk) will be a bottleneck to + +
caseAcc@1Acc@5
first frame70.592.7
random frame70.692.9
middle frame71.093.1
+ +(a) Base frame selection. We perform ablation study to select the base frame as the first, random or the middle frame. + +
caseAcc@1Acc@5
token rand.70.993.0
pixel rand.70.893.0
mixed Gauss71.093.1
+ +(d) Masking initialization. We compare three methods to generate the masking map in the base frame. Two binary random methods and one mixed Gaussian method. + +
caseAcc@1Acc@5
forward70.592.9
backward71.093.1
+ +(b) Warping method. We choose forward or backward warping method for aligning masking maps. + +
caseAcc@1Acc@5
random70.892.9
invisible70.792.8
visible70.893.1
previous map70.692.8
tube71.093.1
+ +(e) Hole filling. We choose some baseline choices to fill the value in the hole place caused by warping. We also use the tube filling consistent with the tube masking. + +
caseAcc@1Acc@5
clip-level70.792.9
frame-level71.093.1
+ +(c) Sampling strategy. We perform a study to choose the visible token generation strategy based on motion guided masking volume. + +
methodtimeAcc@1
None (VideoMAE)32 h69.6
TVL1 (offline)41 h71.2
RAFT with 6 iters43 h71.3
RAFT with 12 iters56 h71.0
+ +(f) Method of optical flow estimation. We perform the ablation study to investigate the influence of different methods of optical flow estimation. +Table 1: Parts of the ablation experiments on the Something-Something V2 dataset. Our MGMAE pre-training is implemented with the 16-frame vanilla ViT-B backbone. All models are pre-trained for 800 epochs and the masking ratio is $\rho = 90\%$ . The inference protocol is to report the fine-tuning action recognition accuracy with 2 clips $\times$ 3 crops. The default choice for our model is colored in gray. Although the default setting is not optimal in terms of the method of optical flow estimation, we believe that this does not affect the conclusions of the ablation experiments. + +increase the training speed. Note that our default setting is not optimal, but the conclusions drawn in other ablation experiments should not be impacted. + +Masking ratio. The performance of MGMAE highlights the importance of improving masking strategies even at high masking rates (e.g. $90\%$ ). However, after applying MGMAE, it remains questionable whether such high masking rates are still necessary. Indeed, as pointed out by [35, 14], blindly increasing the masking rate could potentially degrade the model performance. Our ablation study presented in Fig. 3 shows that sustaining a extremely high masking rate of over $80\%$ is also crucial even with MGMAE. We think the video background and large objects mainly drive the need for a high masking ratio. Video backgrounds are often wide and simple. If the mask ratio is not high enough, the model can still rebuild pixels from other background parts, even if nearby frames mask similar sections. For large objects, a lower ratio might let the model use the texture from a different part of the object when another section is masked. It can also be observed that MGMAE performs optimally with $85\%$ masking ratio, but $90\%$ still seems to be a decent choice when considering the trade-off between training efficiency and performance. + +Exposure of masked objects. Another proposition worth considering is whether occasional exposure of masked objects help with masked video modeling pre-train. We com + +![](images/7570868376420a105af45ff48a1d3f5c3c7f5df0ee119824359108b3acda2e9a.jpg) +Figure 3: The effect of masking ratio on SSV2. + +pleted a complementary experiment. Specifically, after building the masking volume, we add Gaussian noise on the mask map of one randomly selected frame. This modification may provide a chance for masked objects to be exposed. The results showed an accuracy of $71.2\%$ , slightly higher than the default setting of $71.0\%$ . + +# 4.3. Main Results and Visualization Analysis + +After the detailed ablation study on the design of MGMAE, we further perform a deeper analysis by comparing it with the original VideoMAE. We also provide some intermediate visualization results to illustrate the motion guided + +
ModelEpochsK400SSV2
VideoMAE800 / 8000.58750.5278
MGMAE0.64620.5820
Δ loss-Δ + 0.0605Δ + 0.0542
VideoMAE1600 / 24000.58090.5122
MGMAE0.63780.5659
Δ loss-Δ + 0.0569Δ + 0.0537
+ +Table 2: Pre-train loss comparison of MGMAE and Video-MAE. + +
ModelEpochsK400SSV2
VideoMAE800 / 80080.069.6
MGMAE81.271.0
Δ Acc@1-Δ + 1.2%Δ + 1.4%
VideoMAE1600 / 240081.570.8
MGMAE81.872.3
Δ Acc@1-Δ + 0.3%Δ + 1.5%
+ +Table 3: Accuracy comparison of MGMAE and VideoMAE. + +![](images/905abaed5e2b8fe97517709580fbe4be655e20a936c6e87ce5cb5e75ca0ee03b.jpg) +Figure 4: Comparative Accuracy of MGMAE and Video-MAE by Class. + +sampling process. + +Pre-train loss implies a more challenging task. The core design of MGMAE is to dynamically sample the positions of masked token under the guidance of optical flows and aims at increasing the difficulty of the reconstruction task. As can be seen in Tab. 2, the pre-train loss of MGMAE is always larger than that of VideoMAE by more than 0.05. This loss gap implies motion guided masking further suppresses information leakage and indeed constructs a more challenging mask-reconstruct pretext task for masked video modeling. This more difficult task would like to encourage learning more effective representations. + +Detailed breakdown of comparison between MGMAE and VideoMAE. To understand the distinct impacts of the MGMAE and VideoMAE masking strategies on video model pre-training, we delved deeper into the per-class accuracy + +![](images/85b3fc91297b9d7f8e516955684dec58615e306756a751666d116051d95a8fd7.jpg) +Figure 5: Visualization of the video in SSV2 validation set. We present our motion guided mask maps and the reconstructed images. From top to bottom, the original images, the x-direction flows, the y-direction flows, the motion guided mask maps, the masked images and the reconstructed images. + +variations between the two. Fig. 4 showcases the 29 categories with the most pronounced differences in classification accuracy between MGMAE and VideoMAE. + +MGMAE: a more effective video representation learner. MGMAE benefits greatly from the harder task constructed by our motion guided masking strategy. On the one hand, the model has to encode the relationship between visible and invisible tokens harder, which can better guide the model training. On the other hand, the suppression of information leakage may well reduce the overfitting risk of the pretraining, and thus the model can be pre-trained much longer. As shown in Tab. 3, MGMAE consistently maintains an obvious fine-tuning performance gap with VideoMAE on the motion-centric SSV2 dataset (1.4% at 800 epochs and 1.5% at 2400 epochs) and also has some improvement on the scene-centric Kinetics-400 dataset (1.2% at 800 epochs and 0.3% at 1600 epochs). + +Visualization. We randomly seletec a video clip in SSV2 validation set and show its reconstruction example in Fig. 5. We can see that the mask map changes with object movements, which makes it more difficult for the model to reconstruct the original video. + +# 4.4. Comparison with the state-of-the-art methods + +We compare our approach with the previous state-of-the-art methods on the Kinetics-400 and Something-Something V2 datasets. The results are shown in Table 5 and Table 4. + +
MethodBackbonePre-train dataFramesGFLOPsParamAcc@1Acc@5
TEINetEn[24]ResNet50×28+1699×10×35066.5N/A
TANetEn[26]ResNet50×2ImageNet-1K8+1699×2×35166.090.1
TDEN[43]ResNet101×28+16198×1×38869.692.2
SlowFast [15]ResNet101Kinetics-4008+32106×1×35363.187.6
MViTv1 [13]MViTv1-B64455×1×33767.790.9
TimeSformer [5]ViT-BImageNet-21K8196×1×312159.5N/A
TimeSformer [5]ViT-L645549×1×343062.4N/A
ViViT FE [1]ViT-LIN-21K+K40032995×4×3N/A65.989.9
Motionformer [28]ViT-B16370×1×310966.590.1
Motionformer [28]ViT-L321185×1×338268.191.2
Video Swin [25]Swin-B32321×1×38869.692.7
VIMPAC [32]ViT-LHowTo100M+DALLE w/o label10N/A×10×330768.1N/A
BEVT [45]Swin-BIN-1K+K400+DALLE w/o label32321×1×38870.6N/A
MAE-ST1600e [14]ViT-LKinetics-400 w/o label16597×1×330572.193.9
MaskFeat↑312 [48]MViT-LKinetics-600402828×1×321875.095.0
VideoMAE800e [35]ViT-BSSV2 w/o label16180×2×38769.692.0
VideoMAE2400e [35]ViT-B16180×2×38770.892.4
MGMAE800eViT-BSSV2 w/o label16180×2×38771.093.1
MGMAE2400eViT-B16180×2×38772.393.5
+ +Table 4: Comparison on the Something-Something V2 dataset. We only list the results obtained with the similar backbones. + +
MethodBackbonePre-train dataFramesGFLOPsParamAcc@1Acc@5
NL I3D [47]ResNet101ImageNet-1K128359×10×36277.393.3
TANet [26]ResNet15216242×4×35979.394.1
TDEN[43]ResNet1018+16198×10×38879.494.4
TimeSformer [5]ViT-LImageNet-21K968353×1×343080.794.7
ViViT FE [1]ViT-L1283980×1×3N/A81.793.8
Motionformer [28]ViT-L321185×10×338280.294.8
Video Swin [25]Swin-B32282×4×38882.795.5
VIMPAC [32]ViT-LHowTo100M+DALLE w/o label10N/A×10×330777.4N/A
BEVT [45]Swin-BIN-1K+DALLE w/o label32282×4×38880.6N/A
ip-CSN [37]ResNet152None32109×10×33377.892.8
SlowFast [15]R101+NL16+64234×10×36079.893.9
MViTv1 [13]MViTv1-B32170×5×13780.294.4
MAE-ST1600e [14]ViT-BKinetics-400 w/o label16180×7×38781.394.9
VideoMAE800e [35]ViT-B16180×5×38780.094.4
VideoMAE1600e [35]ViT-B16180×5×38781.595.1
MGMAE800eViT-BKinetics-400 w/o label16180×5×38781.294.9
MGMAE1600eViT-B16180×5×38781.895.0
+ +Table 5: Comparison on the Kinetics-400 dataset. We only list the results obtained with the similar backbones. + +For a fair comparison, we mainly list the results with similar computational cost. On the Something-Something V2 dataset, our MGMAE with ViT-B backbone achieves a performance of $72.3\%$ when trained for 2400 epochs, which outperforms the original VideoMAE by $1.5\%$ . On the Kinetics-400 dataset, our MGMAE obtains slightly better performance than the original VideoMAE. The small performance improvement might be ascribed to the fact that Kinetics-400 is a scene-centric action recognition benchmark and motion information is less important compared with the Something-Something dataset. + +# 5. Conclusion + +In this paper, we have proposed the Motion Guided Masked Autoencoders (MGMAE), which adapts the motion guided masking strategy to dynamically sample the + +unmasked visible tokens under the guidance of flows, thus suppressing information leakage to build a more challenging task for masked video pre-training. Experiments have shown that MGMAE has good performance and maintains a high-performance advantage over the previous methods under fair comparison. In addition, our strategy also reduces the risk of pre-training overfitting, which allows the model to benefit from longer pre-training. + +Acknowledgements. This work is supported by the National Key R&D Program of China (No. 2022ZD0160900, No.2022ZD0160100), the National Natural Science Foundation of China (No. 62076119, No. 61921006), Shanghai Committee of Science and Technology (Grant No. 21DZ1100100), and Collaborative Innovation Center of Novel Software Technology and Industrialization. + +# References + +[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In IEEE/CVF International Conference on Computer Vision, 2021. 1, 9 +[2] Wele Gedara Chaminda Bandara, Naman Patel, Ali Gholami, Mehdi Nikkhah, Motilal Agrawal, and Vishal M Patel. Adamae: Adaptive masking for efficient spatiotemporal learning with masked autoencoders. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14507-14517, 2023. 3 +[3] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. BEit: BERT pre-training of image transformers. In International Conference on Learning Representations, 2022. 2 +[4] Wenbo Bao, Wei-Sheng Lai, Chao Ma, Xiaoyun Zhang, Zhiyong Gao, and Ming-Hsuan Yang. Depth-aware video frame interpolation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3703-3712, 2019. 3 +[5] Gedas Bertasius, Heng Wang, and Lorenzo Torresani. Is space-time attention all you need for video understanding? In International Conference on Machine Learning, 2021. 1, 3, 9 +[6] Kelvin CK Chan, Shangchen Zhou, Xiangyu Xu, and Chen Change Loy. Basicvsr++: Improving video superresolution with enhanced propagation and alignment. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5972-5981, 2022. 3 +[7] Mark Chen, Alec Radford, Rewon Child, Jeffrey Wu, Heewoo Jun, David Luan, and Ilya Sutskever. Generative pretraining from pixels. In International Conference on Machine Learning, 2020. 2 +[8] Yutao Cui, Cheng Jiang, Limin Wang, and Gangshan Wu. Mixformer: End-to-end tracking with iterative mixed attention. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1 +[9] Navneet Dalal and Bill Triggs. Histograms of oriented gradients for human detection. In 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR 2005), 20-26 June 2005, San Diego, CA, USA, pages 886-893. IEEE Computer Society, 2005. 2 +[10] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In CVPR, pages 248–255. IEEE Computer Society, 2009. 1 +[11] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In North American Chapter of the Association for Computational Linguistics, 2019. 1, 2 +[12] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2021. 1, 2 +[13] Haoqi Fan, Bo Xiong, Karttikeya Mangalam, Yanghao Li, Zhicheng Yan, Jitendra Malik, and Christoph Feichtenhofer. Multiscale vision transformers. In IEEE/CVF International Conference on Computer Vision, 2021. 9 + +[14] Christoph Feichtenhofer, Haoqi Fan, Yanghao Li, and Kaiming He. Masked autoencoders as spatiotemporal learners. In Advances in Neural Information Processing Systems, 2022. 1, 2, 4, 5, 7, 9 +[15] Christoph Feichtenhofer, Haoqi Fan, Jitendra Malik, and Kaiming He. Slowfast networks for video recognition. In IEEE/CVF International Conference on Computer Vision, 2019. 9 +[16] Raghav Goyal, Samira Ebrahimi Kahou, Vincent Michalski, Joanna Materzynska, Susanne Westphal, Heuna Kim, Valentin Haenel, Ingo Fründ, Peter Yianilos, Moritz Mueller-Freitag, Florian Hoppe, Christian Thurau, Ingo Bax, and Roland Memisevic. The "something something" video database for learning and evaluating visual common sense. In IEEE/CVF International Conference on Computer Vision, 2017. 2, 6 +[17] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1, 2 +[18] Zhewei Huang, Tianyuan Zhang, Wen Heng, Boxin Shi, and Shuchang Zhou. Rife: Real-time intermediate flow estimation for video frame interpolation. arXiv preprint arXiv:2011.06294, 2020.3 +[19] Sunil Hwang, Jaehong Yoon, Youngwan Lee, and Sung Ju Hwang. Efficient video representation learning via masked video modeling with motion-centric token selection. arXiv preprint arXiv:2211.10636, 2022. 3 +[20] Will Kay, Joao Carreira, Karen Simonyan, Brian Zhang, Chloe Hillier, Sudheendra Vijayanarasimhan, Fabio Viola, Tim Green, Trevor Back, Paul Natsev, Mustafa Suleyman, and Andrew Zisserman. The kinetics human action video dataset. arXiv preprint arXiv:1705.06950, 2017. 2, 6 +[21] Heeseung Kwon, Manjin Kim, Suha Kwak, and Minsu Cho. Motionsqueeze: Neural motion feature learning for video understanding. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XVI 16, pages 345-362. Springer, 2020. 3 +[22] Yan Li, Bin Ji, Xintian Shi, Jianguo Zhang, Bin Kang, and Limin Wang. TEA: temporal excitation and aggregation for action recognition. In CVPR, pages 906-915, 2020. 3 +[23] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In IEEE/CVF International Conference on Computer Vision, 2021. 1 +[24] Zhaoyang Liu, Donghao Luo, Yabiao Wang, Limin Wang, Ying Tai, Chengjie Wang, Jilin Li, Feiyue Huang, and Tong Lu. TEINet: Towards an efficient architecture for video recognition. In Proceedings of the AAAI Conference on Artificial Intelligence, 2020. 9 +[25] Ze Liu, Jia Ning, Yue Cao, Yixuan Wei, Zheng Zhang, Stephen Lin, and Han Hu. Video swim transformer. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 9 +[26] Zhaoyang Liu, Limin Wang, Wayne Wu, Chen Qian, and Tong Lu. Tam: Temporal adaptive module for video recognition. + +In IEEE/CVF International Conference on Computer Vision, 2021. 9 +[27] Deepak Pathak, Philipp Krahenbuhl, Jeff Donahue, Trevor Darrell, and Alexei A. Efros. Context encoders: Feature learning by inpainting. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2016. 2 +[28] Mandela Patrick, Dylan Campbell, Yuki M. Asano, Ishaan Misra, Florian Metze, Christoph Feichtenhofer, Andrea Vedaldi, and João F. Henriques. Keeping your eye on the ball: Trajectory attention in video transformers. In NeurIPS, pages 12493-12506, 2021. 3, 9 +[29] Zhiwu Qing, Shiwei Zhang, Ziyuan Huang, Xiang Wang, Yuehuan Wang, Yiliang Lv, Changxin Gao, and Nong Sang. Mar: Masked autoencoders for efficient action recognition. IEEE Transactions on Multimedia, 2023. 2 +[30] Alec Radford, Jeff Wu, Rewon Child, David Luan, Dario Amodei, and Ilya Sutskever. Language models are unsupervised multitask learners. OpenAI blog, 2019. 2 +[31] Karen Simonyan and Andrew Zisserman. Two-stream convolutional networks for action recognition in videos. Advances in Neural Information Processing Systems, 2014. 3 +[32] Hao Tan, Jie Lei, Thomas Wolf, and Mohit Bansal. Vimpac: Video pre-training via masked token prediction and contrastive learning. arXiv preprint arXiv:2106.11250, 2021. 2, 9 +[33] Jing Tan, Jiaqi Tang, Limin Wang, and Gangshan Wu. Relaxed transformer decoders for direct action proposal generation. In IEEE/CVF International Conference on Computer Vision, 2021. 1 +[34] Zachary Teed and Jia Deng. Raft: Recurrent all-pairs field transforms for optical flow. In European conference on computer vision, pages 402-419. Springer, 2020. 2, 5, 6 +[35] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. Video-MAE: Masked autoencoders are data-efficient learners for self-supervised video pre-training. In Advances in Neural Information Processing Systems, 2022. 1, 2, 4, 5, 6, 7, 9 +[36] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Hervé Jégou. Training data-efficient image transformers & distillation through attention. In International Conference on Machine Learning, 2021. 1 +[37] Du Tran, Heng Wang, Matt Feiszli, and Lorenzo Torresani. Video classification with channel-separated convolutional networks. In IEEE/CVF International Conference on Computer Vision, 2019. 9 +[38] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Advances in Neural Information Processing Systems, 2017. 1 +[39] Pascal Vincent, Hugo Larochelle, Yoshua Bengio, and Pierre-Antoine Manzagol. Extracting and composing robust features with denoising autoencoders. In International Conference on Machine Learning, 2008. 2 +[40] Pascal Vincent, Hugo Larochelle, Isabelle Lajoie, Yoshua Bengio, and Pierre-Antoine Manzagol. Stacked denoising autoencoders: Learning useful representations in a deep network with a local denoising criterion. Journal of Machine Learning Research, 2010. 2 + +[41] Limin Wang, Bingkun Huang, Zhiyu Zhao, Zhan Tong, Yinan He, Yi Wang, Yali Wang, and Yu Qiao. Videomae v2: Scaling video masked autoencoders with dual masking. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14549-14560, 2023. 1, 2 +[42] Limin Wang, Yu Qiao, and Xiaou Tang. Action recognition with trajectory-pooled deep-convolutional descriptors. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2015, Boston, MA, USA, June 7-12, 2015, pages 4305-4314. IEEE Computer Society, 2015. 3 +[43] Limin Wang, Zhan Tong, Bin Ji, and Gangshan Wu. TDN: Temporal difference networks for efficient action recognition. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. 3, 9 +[44] Limin Wang, Yuanjun Xiong, Zhe Wang, Yu Qiao, Dahua Lin, Xiaou Tang, and Luc Van Gool. Temporal segment networks for action recognition in videos. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2019. 3 +[45] Rui Wang, Dongdong Chen, Zuxuan Wu, Yinpeng Chen, Xiyang Dai, Mengchen Liu, Yu-Gang Jiang, Luowei Zhou, and Lu Yuan. Bevt: Bert pretraining of video transformers. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2, 9 +[46] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In IEEE/CVF International Conference on Computer Vision, 2021. 1 +[47] Xiaolong Wang, Ross Girshick, Abhinav Gupta, and Kaiming He. Non-local neural networks. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2018. 9 +[48] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2, 9 +[49] Enze Xie, Wenhai Wang, Zhiding Yu, Anima Anandkumar, Jose M Alvarez, and Ping Luo. Segformer: Simple and efficient design for semantic segmentation with transformers. In Advances in Neural Information Processing Systems, 2021. 1 +[50] Zhenda Xie, Zheng Zhang, Yue Cao, Yutong Lin, Jianmin Bao, Zhuliang Yao, Qi Dai, and Han Hu. Simmim: A simple framework for masked image modeling. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2 +[51] Xitong Yang, Xiaodong Yang, Sifei Liu, Deqing Sun, Larry Davis, and Jan Kautz. Hierarchical contrastive motion learning for video action recognition. arXiv preprint arXiv:2007.10321, 2020. 3 +[52] Li Yuan, Yunpeng Chen, Tao Wang, Weihao Yu, Yujun Shi, Francis EH Tay, Jiashi Feng, and Shuicheng Yan. Token-to-token vit: Training vision transformers from scratch onImagenet. In IEEE/CVF International Conference on Computer Vision, 2021. 1 +[53] Christopher Zach, Thomas Pock, and Horst Bischof. A duality based approach for realtime tv-1 optical flow. In + +Pattern Recognition: 29th DAGM Symposium, Heidelberg, Germany, September 12-14, 2007. Proceedings 29, pages 214-223. Springer, 2007. 5 +[54] Chen-Lin Zhang, Jianxin Wu, and Yin Li. Actionformer: Localizing moments of actions with transformers. CoRR, abs/2202.07925, 2022. 1 +[55] Guozhen Zhang, Yuhan Zhu, Haonan Wang, Youxin Chen, Gangshan Wu, and Limin Wang. Extracting motion and appearance via inter-frame attention for efficient video frame interpolation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5682-5692, 2023. 3 +[56] Kaidong Zhang, Jingjing Fu, and Dong Liu. Flow-guided transformer for video inpainting. In European Conference on Computer Vision, pages 74-90. Springer, 2022. 3 +[57] Yue Zhao, Yuanjun Xiong, and Dahua Lin. Trajectory convolution for action recognition. In Samy Bengio, Hanna M. Wallach, Hugo Larochelle, Kristen Grauman, Nicolò Cesà-Bianchi, and Roman Garnett, editors, Advances in Neural Information Processing Systems 31: Annual Conference on Neural Information Processing Systems 2018, NeurIPS 2018, December 3-8, 2018, Montréal, Canada, pages 2208-2219, 2018. 3 +[58] Yuan Zhi, Zhan Tong, Limin Wang, and Gangshan Wu. Mgsampler: An explainable sampling strategy for video action recognition. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 1493-1502. IEEE, 2021. 3 +[59] Daquan Zhou, Bingyi Kang, Xiaojie Jin, Linjie Yang, Xiaochen Lian, Qibin Hou, and Jiashi Feng. Deepvit: Towards deeper vision transformer. arXiv preprint arXiv:2103.11886, 2021. 1 \ No newline at end of file diff --git a/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/images.zip b/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..ffaa4d8647d5ca2ec4def343b9f0cdc8faf5e0f6 --- /dev/null +++ b/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:e770c194093581e5bfe1ede9bc6ea114e1e752acc2513e937d58daa0720f6483 +size 560077 diff --git a/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/layout.json b/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..a39782a8a247409eb7aebf0ebb8bef3b85914398 --- /dev/null +++ b/2023/MGMAE_ Motion Guided Masking for Video Masked Autoencoding/layout.json @@ -0,0 +1,8890 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 86, + 103, + 507, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 86, + 103, + 507, + 121 + ], + "spans": [ + { + "bbox": [ + 86, + 103, + 507, + 121 + ], + "type": "text", + "content": "MGMAE: Motion Guided Masking for Video Masked Autoencoding" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "spans": [ + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "text", + "content": "Bingkun Huang" + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "inline_equation", + "content": "^{1,2}" + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "text", + "content": " Zhiyu Zhao" + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "inline_equation", + "content": "^{1,2}" + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "text", + "content": " Guozhen Zhang" + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "text", + "content": " Yu Qiao" + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "text", + "content": " Limin Wang" + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "inline_equation", + "content": "^{1,2,\\text{图}}" + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "text", + "content": " State Key Laboratory for Novel Software Technology, Nanjing University " + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 62, + 141, + 531, + 193 + ], + "type": "text", + "content": " Shanghai AI Lab https://github.com/MCG-NJU/MGMAE" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "spans": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 238, + 290, + 525 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 238, + 290, + 525 + ], + "spans": [ + { + "bbox": [ + 46, + 238, + 290, + 525 + ], + "type": "text", + "content": "Masked autoencoding has shown excellent performance on self-supervised video representation learning. Temporal redundancy has led to a high masking ratio and customized masking strategy in VideoMAE. In this paper, we aim to further improve the performance of video masked autoencoding by introducing a motion guided masking strategy. Our key insight is that motion is a general and unique prior in video, which should be taken into account during masked pretraining. Our motion guided masking explicitly incorporates motion information to build temporal consistent masking volume. Based on this masking volume, we can track the unmasked tokens in time and sample a set of temporal consistent cubes from videos. These temporal aligned unmasked tokens will further relieve the information leakage issue in time and encourage the MGMAE to learn more useful structure information. We implement our MGMAE with an online efficient optical flow estimator and backward masking map warping strategy. We perform experiments on the datasets of Something-Something V2 and Kinetics-400, demonstrating the superior performance of our MGMAE to the original VideoMAE. In addition, we provide the visualization analysis to illustrate that our MGMAE can sample temporal consistent cubes in a motion-adaptive manner for more effective video pre-training." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 543, + 128, + 555 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 543, + 128, + 555 + ], + "spans": [ + { + "bbox": [ + 47, + 543, + 128, + 555 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 563, + 288, + 695 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 563, + 288, + 695 + ], + "spans": [ + { + "bbox": [ + 46, + 563, + 288, + 695 + ], + "type": "text", + "content": "Attention-based Transformer [38] has witnessed great success in computer vision since the introduction of Vision Transformer (ViT) [12]. It has been applied for a variety of vision tasks and obtains state-of-the-art performance, such as image classification [36, 59, 52], object detection [23, 46], semantic segmentation [49], and object tracking [8]. Thanks to this high performance, ViT models have been also applied to the video domain for action recognition [5, 1] and detection [33, 54]. However, the high capacity of Transformer often demands pre-training on a large-scale dataset to reduce the over-fitting risk of subsequent fine" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 310, + 211, + 420, + 264 + ], + "blocks": [ + { + "bbox": [ + 310, + 211, + 420, + 264 + ], + "lines": [ + { + "bbox": [ + 310, + 211, + 420, + 264 + ], + "spans": [ + { + "bbox": [ + 310, + 211, + 420, + 264 + ], + "type": "image", + "image_path": "d4dab8bfd4010748a06b3de6e48e1ee025825d8792f44d5a49846a90d466612f.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 309, + 281, + 418, + 334 + ], + "blocks": [ + { + "bbox": [ + 325, + 270, + 405, + 281 + ], + "lines": [ + { + "bbox": [ + 325, + 270, + 405, + 281 + ], + "spans": [ + { + "bbox": [ + 325, + 270, + 405, + 281 + ], + "type": "text", + "content": "(a) original video clip" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 309, + 281, + 418, + 334 + ], + "lines": [ + { + "bbox": [ + 309, + 281, + 418, + 334 + ], + "spans": [ + { + "bbox": [ + 309, + 281, + 418, + 334 + ], + "type": "image", + "image_path": "a1f20a198bd90758e6c3ee15b54d130e39e5d2ae73f60a40e39f39d400530110.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 328, + 338, + 402, + 349 + ], + "lines": [ + { + "bbox": [ + 328, + 338, + 402, + 349 + ], + "spans": [ + { + "bbox": [ + 328, + 338, + 402, + 349 + ], + "type": "text", + "content": "(c) random masking" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 304, + 358, + 547, + 455 + ], + "lines": [ + { + "bbox": [ + 304, + 358, + 547, + 455 + ], + "spans": [ + { + "bbox": [ + 304, + 358, + 547, + 455 + ], + "type": "text", + "content": "Figure 1: Comparison of different masking strategies. Masked autoencoding [11, 17] has been explored in video domain for self-supervised pre-training by employing different masking strategies: random masking [14] and tube masking [35]. We propose to track masking maps under the guidance of motion information (termed as motion guided masking). Our resulting MGMAE can build a more challenging and meaningful task for video pre-training." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 432, + 211, + 542, + 264 + ], + "blocks": [ + { + "bbox": [ + 432, + 211, + 542, + 264 + ], + "lines": [ + { + "bbox": [ + 432, + 211, + 542, + 264 + ], + "spans": [ + { + "bbox": [ + 432, + 211, + 542, + 264 + ], + "type": "image", + "image_path": "ddb52fbe1b47eebe164b05caf6541ce36ee9c4a233a060042c877eb5d81fa49b.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 430, + 280, + 545, + 333 + ], + "blocks": [ + { + "bbox": [ + 456, + 270, + 518, + 280 + ], + "lines": [ + { + "bbox": [ + 456, + 270, + 518, + 280 + ], + "spans": [ + { + "bbox": [ + 456, + 270, + 518, + 280 + ], + "type": "text", + "content": "(b) tube masking" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 430, + 280, + 545, + 333 + ], + "lines": [ + { + "bbox": [ + 430, + 280, + 545, + 333 + ], + "spans": [ + { + "bbox": [ + 430, + 280, + 545, + 333 + ], + "type": "image", + "image_path": "2415c759021d623aeab12bdfef0c56a17bbfee998738cbe4ca04de3213372218.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 438, + 338, + 537, + 349 + ], + "lines": [ + { + "bbox": [ + 438, + 338, + 537, + 349 + ], + "spans": [ + { + "bbox": [ + 438, + 338, + 537, + 349 + ], + "type": "text", + "content": "(d) motion guided masking" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 461, + 545, + 497 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 461, + 545, + 497 + ], + "spans": [ + { + "bbox": [ + 304, + 461, + 545, + 497 + ], + "type": "text", + "content": "tuning. Therefore, an effective pretraining strategy of ViT is particularly important for obtaining excellent performance in the video domain due to the smaller video dataset." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 498, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 498, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 498, + 547, + 714 + ], + "type": "text", + "content": "The early video transformers [1, 5] often rely on the pre-training of image-based transformer derived from the large-scale image dataset [10]. This pre-training scheme makes the learnt video model to be naturally biased by image-based ViTs. Recently, masked autoencoding (MAE) [35, 14, 41] has been explored for pre-training video transformer on the video dataset due to its simplicity and promising result in image domain [17]. However, unlike the image, video data is equipped with an extra time dimension and exhibits the unique property of temporal redundancy and correlation. This property requires some customized designs on video masked autoencoder compared with image-based MAE. For example, VideoMAE and MAE-ST both propose to use an extremely high masking ratio in video masked autoencoder pre-training to improve its performance. In addition, VideoMAE devises a tube masking strategy of dropping tokens at the same position across frames to further relieve the information leakage in time. This tube masking" + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 61, + 703, + 220, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 703, + 220, + 713 + ], + "spans": [ + { + "bbox": [ + 61, + 703, + 220, + 713 + ], + "type": "inline_equation", + "content": "\\boxtimes" + }, + { + "bbox": [ + 61, + 703, + 220, + 713 + ], + "type": "text", + "content": " : Corresponding author (lmwang@nju.edu.cn)." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13493" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 286, + 119 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 286, + 119 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 286, + 119 + ], + "type": "text", + "content": "approach, though straightforward, makes the assumption of no or small motion occurring between adjacent frames. Such an assumption might be not true for some scenarios with high-speed motion." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 126, + 286, + 329 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 126, + 286, + 329 + ], + "spans": [ + { + "bbox": [ + 48, + 126, + 286, + 329 + ], + "type": "text", + "content": "Based on the above analysis, in this paper, we aim to propose a new masking strategy for improving video masked autoencoder pre-training, by explicitly using motion information to reduce information leakage in time. Specifically, we devise the Motion Guided Masking in the video masked encoder processing and the resulted masked autoencoder is termed as MGMAE. Motion is general prior information contained by video. The optical flow representation explicitly encodes the movement of each pixel from the current frame to the next one. We propose to use this optical flow to align masking maps between adjacent frames to build consistent masking volumes across time. The consistent masking volumes enable to build a more challenging reconstruction task by enforcing only a small set of cube tracks visible to the encoder. Hopefully, this motion guided masking can further relieve the risk of information leakage in time and encourage learning more meaningful visual representations." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 336, + 286, + 538 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 336, + 286, + 538 + ], + "spans": [ + { + "bbox": [ + 48, + 336, + 286, + 538 + ], + "type": "text", + "content": "More specifically, we use an online and lightweight optical flow estimator (RAFT [34]) to capture motion information, which could be seamlessly integrated into the existing VideoMAE framework. To build the temporally consistent masking volume, we first randomly generate an initial masking map at the base frame. Then, we use the estimated optical flow to warp the initial masking map to adjacent frames. With multiple warping operations, we build the temporal consistent masking volume for all frames in the video. Finally, based on this masking volume, we sample a set of visible tokens to MAE encoders with top-k selection based on a frame-wise manner. The same autoencoding process with the original VideoMAE is applied to these sampled tokens for video pretraining. With this simple motion guided masking, we are able to further increase the difficulty of video pre-training task and thus lead to a better pre-trained model for subsequent fine-tuning." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 546, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 546, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 546, + 286, + 712 + ], + "type": "text", + "content": "We mainly verify the effectiveness of the proposed MGMAE on the datasets of Something-Something V2 [16] and Kinetics-400 [20] by comparing them with the original tube masking in VideoMAE. The results demonstrate that MGMAE pre-training can result in more powerful video foundation models with higher fine-tuning accuracy on the downstream tasks. In particular, on the motion-centric benchmark of Something-Something, the improvement of MGMAE is more evident, implying that our motion guided masking is adaptive to motion variations and can better capture temporal structure information for pre-training. We hope our findings can inspire some specific and unique designs in video masked autoencoding with respect to image counterparts." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 309, + 72, + 391, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 72, + 391, + 83 + ], + "spans": [ + { + "bbox": [ + 309, + 72, + 391, + 83 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 308, + 91, + 545, + 401 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 91, + 545, + 401 + ], + "spans": [ + { + "bbox": [ + 308, + 91, + 545, + 401 + ], + "type": "text", + "content": "Masked Visual Modeling. Masked autoencoder is a long-standing unsupervised learning framework in computer vision. The early work presented general form of denoising autoencoder [40, 39] for learning representation by reconstructing the clean signal from the noisy inputs. The other work [27] also treated masking modeling as inpainting missing regions from the surrounding context by using convolutions. Inspired by the great success of masked language modeling [11], some works also attempted to apply this pretraining paradigm to the vision domain for self-supervised pre-training. For example, iGPT [7] followed the GPT work [30] in NLP and processed a sequence of pixels for casual prediction of the next pixels. The original ViT [12] used the masked token prediction as a self-supervised training step on large-scale image datasets but failed to obtain impressive results. Recently, several interesting works have obtained a great breakthrough in self-supervised image pre-training by using masked image modeling, such as BEiT [3], SimMIM [50], and MAE [17]. BEiT [3] directly followed the BERT framework and proposed to predict the discrete token label for masked patches, by requiring an explicit tokenizer to build the token dictionary. SimMIM [50] and MAE [17] shared the same design of directly predicting the pixels of masked patches without any tokenizer design. Furthermore, MAE [17] devised an asymmetric encoder-decoder architecture to speed up the masked image pre-training." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 308, + 403, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 403, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 403, + 545, + 712 + ], + "type": "text", + "content": "Since the great success in masked image modeling, some works have tried to extend this new pre-training paradigm to the video domain for self-supervised video pre-training. BEVT [45] and VIMPAC [32] proposed to learn video representation by predicting discrete visual tokens in a similar way to BEiT. However, their performance improvement in video action recognition is limited. MaskFeat [48] used the HOG features [9] as the reconstructed targets of masked patches and achieved excellent performance on the video recognition with a multi-scale vision transformer. VideoMAE [35] and MAE-ST [14] extended the image MAE to the video domain for representation learning with vanilla vision transformer. They both proposed to use an extremely high masking ratio to deal with video data redundancy. Meanwhile, VideoMAE [35] used the tube masking to further increase the difficulty of reconstruction. Several works building upon VideoMAE have emerged. For instance, MAR [29] reduced both training and inference costs by introducing running cell masking. Meanwhile, VideoMAE V2 [41] proposes a dual masking strategy to decrease pre-training overhead, and by expanding both the model size and dataset, it further explores the scalability of VideoMAE. Our proposed motion guided masking aims to improve the performance of VideoMAE by building a more challenging masking and reconstruction task. In contrast to the original VideoMAE, our MGMAE explicitly use the optical flow to align the masking maps" + } + ] + } + ], + "index": 6 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 750, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 750, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 750, + 317, + 757 + ], + "type": "text", + "content": "13494" + } + ] + } + ], + "index": 7 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "type": "text", + "content": "across frames and generate the temporal consistent masking volume to sample a set of visible tokens." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 110, + 289, + 661 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 110, + 289, + 661 + ], + "spans": [ + { + "bbox": [ + 47, + 110, + 289, + 661 + ], + "type": "text", + "content": "Motion Guided Modeling. Motion information, such as optical flow, is a general prior information in videos and represents the unique characteristics distinct from images. Optical flow has been widely introduced to provide a strong prior in both low-level and high-level vision tasks on video. For low-level video tasks, the motion is often used to align the information of auxiliary frames to the corresponding region of the target frame. In the case of video super-resolution, BasicVSR++ [6] uses optical flow to enhance the appearance of low-resolution frames by transferring features from neighbor frames. For video inpainting, Zhang et al. [56] exploits the motion difference extracted by optical flows to instruct the attention retrieval in transformer for high-fidelity video inpainting. As for video frame interpolation, mainstream methods leverage optical flow directly on the image to synthesize the intermediate frame, such as DAIN [4] and RIFE [18], while Zhang et al. [55] introduces a unified operation utilizing inter-frame attention to concurrently extract motion and appearance information, and blends a hybrid CNN and Transformer design for efficiency and fine-grained detail preservation. For high-level video tasks, the optical flow is directly used as a data modality as network input for action recognition [44, 31]. TDD [42] utilized motion trajectories to pool deep convolutional features for action recognition. Trajectory Convolution [57] incorporated the motion information into temporal convolutional kernel design. MSNet [21] proposes a pluggable MotionSqueeze module to generate motion information across frames. VideoMS [19] generates mask maps by calculating the feature difference after patch embedding, making an attempt at dynamically adjusting mask positions. AdaMAE [2] introduces an end-to-end trainable adaptive masking strategy for MAEs, leveraging an auxiliary sampling network to prioritize tokens from high spatiotemporal information regions. Yang et al. [51] leverage hierarchical motion information to improve the extracted video features. MotionFormer [28] employed the trajectory for attention computation in the video transformer. TEA [22] and TDN [43] used RGB difference to approximate the motion information and incorporate this information into the video CNN backbone design. MGSampler [58] explored the motion information to select a subset of representative frames for efficient video action recognition. Our MGMAE shares the same spirit with these motion guided modeling works. We focus on employing motion information as a cue to generate masking maps for masked video pre-training." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 669, + 103, + 681 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 669, + 103, + 681 + ], + "spans": [ + { + "bbox": [ + 47, + 669, + 103, + 681 + ], + "type": "text", + "content": "3. Method" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 689, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 288, + 713 + ], + "type": "text", + "content": "In this section, we first revisit the pre-training paradigm of VideoMAE to well introduce our MGMAE in Sec. 3.1." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 305, + 72, + 547, + 109 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 547, + 109 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 547, + 109 + ], + "type": "text", + "content": "Then we present the details of motion guided masking map generation in Sec. 3.2. Finally, we describe the MGMAE pretraining under temporal consistent masking maps in Sec. 3.3." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 305, + 118, + 424, + 130 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 118, + 424, + 130 + ], + "spans": [ + { + "bbox": [ + 305, + 118, + 424, + 130 + ], + "type": "text", + "content": "3.1. VideoMAE revisited" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 137, + 547, + 186 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 137, + 547, + 186 + ], + "spans": [ + { + "bbox": [ + 305, + 137, + 547, + 186 + ], + "type": "text", + "content": "VideoMAE is a simple masked video autoencoder with an asymmetric encoder-decoder architecture with an extra cube embedding to handle the input sampled frames. Next, we briefly revisit its implementation detail." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "spans": [ + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "text", + "content": "Cube Embedding. VideoMAE divides the input video clip " + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "inline_equation", + "content": "\\mathbf{I}" + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "text", + "content": " of size " + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "inline_equation", + "content": "T\\times 3\\times H\\times W" + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "text", + "content": " into non-overlapping cubes " + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "inline_equation", + "content": "\\mathbf{C} = \\{\\mathbf{C}_i\\mid \\mathbf{C}_i\\in \\mathbb{R}^{2\\times 16\\times 16\\times 3}\\}_{i = 1}^N" + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "inline_equation", + "content": "N = \\frac{T}{2}\\times \\frac{H}{16}\\times \\frac{W}{16}" + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "text", + "content": " is the number of cubes. Then apply cube embedding on the cubes to produce the video tokens " + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "inline_equation", + "content": "\\mathbf{T} = \\{\\mathbf{T}_i\\mid \\mathbf{T}_i\\in \\mathbb{R}^D\\}_{i = 1}^N" + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "inline_equation", + "content": "T_{i}" + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "text", + "content": " represents the cube embedding with positional encoding, and " + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 305, + 205, + 547, + 295 + ], + "type": "text", + "content": " is the channel." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "spans": [ + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "text", + "content": "Masking Strategy. VideoMAE uses the tube masking strategy with an extremely high masking ratio " + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "inline_equation", + "content": "\\rho" + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "text", + "content": " (i.e. " + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "inline_equation", + "content": "90\\%" + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "text", + "content": "), which samples the same spatial positions across all frames of the input video clip. Specifically, VideoMAE first generate a " + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "inline_equation", + "content": "\\frac{H}{16} \\times \\frac{W}{16}" + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "text", + "content": " binary mask map " + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "inline_equation", + "content": "\\mathbf{M}'" + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "text", + "content": " where 0 represents unmasked and 1 represents masked. Then it replicates it in temporal dimension and then flattens it to produce the token-level mask map " + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "inline_equation", + "content": "\\mathbf{M}" + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "text", + "content": " whose size is " + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "text", + "content": " for the input video clip. We denote " + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "inline_equation", + "content": "\\mathbb{M}" + }, + { + "bbox": [ + 305, + 315, + 547, + 423 + ], + "type": "text", + "content": " as the masking maps." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 442, + 547, + 514 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 442, + 547, + 514 + ], + "spans": [ + { + "bbox": [ + 305, + 442, + 547, + 514 + ], + "type": "text", + "content": "Encoder. The encoder is a vanilla ViT with joint space-time attention [5]. For computation efficiency, only the unmasked visible tokens " + }, + { + "bbox": [ + 305, + 442, + 547, + 514 + ], + "type": "inline_equation", + "content": "\\mathbf{T}^v = \\{\\mathbf{T}_i\\}_{i\\notin \\mathbb{M}}" + }, + { + "bbox": [ + 305, + 442, + 547, + 514 + ], + "type": "text", + "content": " added with the fixed positional embedding are fed into the encoder to obtain the latent features " + }, + { + "bbox": [ + 305, + 442, + 547, + 514 + ], + "type": "inline_equation", + "content": "\\mathbf{Z}" + }, + { + "bbox": [ + 305, + 442, + 547, + 514 + ], + "type": "text", + "content": " of size " + }, + { + "bbox": [ + 305, + 442, + 547, + 514 + ], + "type": "inline_equation", + "content": "N_v\\times D" + }, + { + "bbox": [ + 305, + 442, + 547, + 514 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 305, + 442, + 547, + 514 + ], + "type": "inline_equation", + "content": "N_{v} = \\lfloor (1 - \\rho)N\\rfloor" + }, + { + "bbox": [ + 305, + 442, + 547, + 514 + ], + "type": "text", + "content": " is the total number of the unmasked visible tokens." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 534, + 547, + 617 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 534, + 547, + 617 + ], + "spans": [ + { + "bbox": [ + 305, + 534, + 547, + 617 + ], + "type": "text", + "content": "Decoder. The decoder is a narrower and shallower ViT than the encoder. It takes the concatenated token sequences as input, which is formed by the concatenation between the latent features " + }, + { + "bbox": [ + 305, + 534, + 547, + 617 + ], + "type": "inline_equation", + "content": "\\mathbf{Z}" + }, + { + "bbox": [ + 305, + 534, + 547, + 617 + ], + "type": "text", + "content": " and the learnable [MASK] tokens with the fixed position embedding added, to reconstruct the normalized video cubes " + }, + { + "bbox": [ + 305, + 534, + 547, + 617 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{C}} = \\left\\{\\hat{\\mathbf{C}}_i \\mid \\hat{\\mathbf{C}}_i \\in \\mathbb{R}^{2 \\times 16 \\times 16 \\times 3}\\right\\}_{i=1}^N" + }, + { + "bbox": [ + 305, + 534, + 547, + 617 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 634, + 545, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 634, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 305, + 634, + 545, + 677 + ], + "type": "text", + "content": "Loss. The pre-training object is to minimize the Mean Square Error Loss between the normalized " + }, + { + "bbox": [ + 305, + 634, + 545, + 677 + ], + "type": "inline_equation", + "content": "\\mathbf{C}" + }, + { + "bbox": [ + 305, + 634, + 545, + 677 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 634, + 545, + 677 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{C}}" + }, + { + "bbox": [ + 305, + 634, + 545, + 677 + ], + "type": "text", + "content": " on the masked positions, i.e. " + }, + { + "bbox": [ + 305, + 634, + 545, + 677 + ], + "type": "inline_equation", + "content": "\\frac{1}{\\rho N} \\sum_{i \\in \\mathbb{M}} \\left| \\hat{\\mathbf{C}}_i - \\mathrm{norm}(\\mathbf{C}_i) \\right|^2" + }, + { + "bbox": [ + 305, + 634, + 545, + 677 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "content": "After the pre-training, the encoder will be used as the backbone network to fine-tune on the downstream tasks to obtain a specialized model." + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13495" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 65, + 76, + 527, + 304 + ], + "blocks": [ + { + "bbox": [ + 65, + 76, + 527, + 304 + ], + "lines": [ + { + "bbox": [ + 65, + 76, + 527, + 304 + ], + "spans": [ + { + "bbox": [ + 65, + 76, + 527, + 304 + ], + "type": "image", + "image_path": "3cdb054ac6de8fe38e81bf3be96d5041084f8f4dba66d980c38d9ebe40945d87.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 319, + 548, + 381 + ], + "lines": [ + { + "bbox": [ + 46, + 319, + 548, + 381 + ], + "spans": [ + { + "bbox": [ + 46, + 319, + 548, + 381 + ], + "type": "text", + "content": "Figure 2: Pipeline of MGMAE. Our MGMAE follows the simple pipeline of masking and reconstruction for video self-supervised pre-training. Our core design is to propose a motion guided masking strategy to generate temporal consistent masking volume. With this masking volume, we track the visible cubes and attain temporal consistency for masking maps. As a result, we can build a more challenging reconstruction task and encourage extracting more effective representations during masked self-supervised pretraining." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 400, + 211, + 415 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 400, + 211, + 415 + ], + "spans": [ + { + "bbox": [ + 47, + 400, + 211, + 415 + ], + "type": "text", + "content": "3.2. Motion Guided Masking Map" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 426, + 290, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 426, + 290, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 426, + 290, + 715 + ], + "type": "text", + "content": "Time is a unique characteristic of video and has different properties with the space dimension. When devising masked video autoencoder, we need to carefully take this extra time dimension into account and come up with a customized design. Information leakage in time is an important issue in masked video pre-training. When information leakage occurs, the model can easily reconstruct the masked cubes based on the visible tokens of adjacent frames. In this case, it will greatly reduce the difficulty of the reconstruction task and lead to a pre-trained model with poor fine-tuning performance. A trivial solution to information leakage is to increase the masking ratio. VideoMAE [35] and MAE-ST [14] increase the masking ratio to " + }, + { + "bbox": [ + 46, + 426, + 290, + 715 + ], + "type": "inline_equation", + "content": "90\\%" + }, + { + "bbox": [ + 46, + 426, + 290, + 715 + ], + "type": "text", + "content": " to greatly increase the difficulty of reconstruction. In addition, VideoMAE makes the small motion assumption and adapts the tube masking strategy, which masks the same spatial position in all frames. However, this small motion prior is not always true for motion-dominated videos. A more reasonable approach is to keep each object in the video clip visible or invisible at all times. To achieve this goal, we propose the motion guided masking strategy to replace the tube masking strategy in VideoMAE. The strategy has two procedures: we first use the optical flow as guidance to generate temporally consistent masking volumes of the input video clip" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 304, + 401, + 545, + 436 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 401, + 545, + 436 + ], + "spans": [ + { + "bbox": [ + 304, + 401, + 545, + 436 + ], + "type": "text", + "content": "and then sample the unmasked visible tokens based on the temporal consistent masking volume. We will detail these two procedures in Sec. 3.2 and Sec. 3.3." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 437, + 545, + 461 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 437, + 545, + 461 + ], + "spans": [ + { + "bbox": [ + 304, + 437, + 545, + 461 + ], + "type": "text", + "content": "In general, the procedure for generating the temporal consistent masking volumes has four steps as follows." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 317, + 471, + 545, + 613 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 317, + 471, + 545, + 493 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 471, + 545, + 493 + ], + "spans": [ + { + "bbox": [ + 317, + 471, + 545, + 493 + ], + "type": "text", + "content": "- Step 1: Determine the base frame " + }, + { + "bbox": [ + 317, + 471, + 545, + 493 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_b" + }, + { + "bbox": [ + 317, + 471, + 545, + 493 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 317, + 471, + 545, + 493 + ], + "type": "inline_equation", + "content": "b" + }, + { + "bbox": [ + 317, + 471, + 545, + 493 + ], + "type": "text", + "content": " is the index of the base frame." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 502, + 545, + 528 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 502, + 545, + 528 + ], + "spans": [ + { + "bbox": [ + 317, + 502, + 545, + 528 + ], + "type": "text", + "content": "- Step 2: Randomly generate a pixel-level initial mask map " + }, + { + "bbox": [ + 317, + 502, + 545, + 528 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_b" + }, + { + "bbox": [ + 317, + 502, + 545, + 528 + ], + "type": "text", + "content": " with size " + }, + { + "bbox": [ + 317, + 502, + 545, + 528 + ], + "type": "inline_equation", + "content": "H \\times W" + }, + { + "bbox": [ + 317, + 502, + 545, + 528 + ], + "type": "text", + "content": " as the mask map of " + }, + { + "bbox": [ + 317, + 502, + 545, + 528 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_b" + }, + { + "bbox": [ + 317, + 502, + 545, + 528 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 534, + 545, + 559 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 534, + 545, + 559 + ], + "spans": [ + { + "bbox": [ + 317, + 534, + 545, + 559 + ], + "type": "text", + "content": "- Step 3: Extract the dense flows " + }, + { + "bbox": [ + 317, + 534, + 545, + 559 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 317, + 534, + 545, + 559 + ], + "type": "text", + "content": " bidirectionally from the base frame " + }, + { + "bbox": [ + 317, + 534, + 545, + 559 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_b" + }, + { + "bbox": [ + 317, + 534, + 545, + 559 + ], + "type": "text", + "content": " in the input video clip " + }, + { + "bbox": [ + 317, + 534, + 545, + 559 + ], + "type": "inline_equation", + "content": "\\mathbf{I}" + }, + { + "bbox": [ + 317, + 534, + 545, + 559 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 317, + 567, + 545, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 567, + 545, + 613 + ], + "spans": [ + { + "bbox": [ + 317, + 567, + 545, + 613 + ], + "type": "text", + "content": "- Step 4: Warp the initial masking map " + }, + { + "bbox": [ + 317, + 567, + 545, + 613 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_b" + }, + { + "bbox": [ + 317, + 567, + 545, + 613 + ], + "type": "text", + "content": " under the guidance of dense flows " + }, + { + "bbox": [ + 317, + 567, + 545, + 613 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 317, + 567, + 545, + 613 + ], + "type": "text", + "content": " and progressively build the temporal consistent masking volume " + }, + { + "bbox": [ + 317, + 567, + 545, + 613 + ], + "type": "inline_equation", + "content": "\\mathbf{M}" + }, + { + "bbox": [ + 317, + 567, + 545, + 613 + ], + "type": "text", + "content": " of size " + }, + { + "bbox": [ + 317, + 567, + 545, + 613 + ], + "type": "inline_equation", + "content": "T \\times H \\times W" + }, + { + "bbox": [ + 317, + 567, + 545, + 613 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "type": "text", + "content": "Determine the base frame. By default, we choose the middle frame as the base frame. In motion guided masking, we need to ensure all objects in the base frame remain consistently visible or invisible in all frames of the input clip. Note that objects may (dis)appear over time due to object or camera movement, and warping the masking map under optical flow can result in some holes due to pixels mapped" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "13496" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 288, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 288, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 288, + 120 + ], + "type": "text", + "content": "out of bounds. So the choice of the base frame may have an impact on the suppression of information leakage. We ablate the choice of the base frame in Sec. 4.2 and the middle frame is the optimal choice." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 134, + 287, + 229 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 134, + 287, + 229 + ], + "spans": [ + { + "bbox": [ + 46, + 134, + 287, + 229 + ], + "type": "text", + "content": "Generate the initial mask map. We initialize a pixel-level masking map for the base frame with the distribution of the Gaussian Mixture Model (GMM). We use the masking map to indicate the visible or invisible state of the cubes in the base frame. Previous masking strategies usually adapt a token-level binary initialization, i.e. either all 0 or all 1 within each token of size " + }, + { + "bbox": [ + 46, + 134, + 287, + 229 + ], + "type": "inline_equation", + "content": "2 \\times 16 \\times 16" + }, + { + "bbox": [ + 46, + 134, + 287, + 229 + ], + "type": "text", + "content": ", which actually breaks the continuity of the object surface texture." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "spans": [ + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "type": "text", + "content": "Specifically, we first randomly pick " + }, + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "type": "inline_equation", + "content": "\\hat{N}_v = \\left\\lfloor (1 - \\rho) \\times \\frac{H}{16} \\times \\frac{W}{16} \\right\\rfloor" + }, + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "type": "text", + "content": " tokens whose centers are denoted with " + }, + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "type": "inline_equation", + "content": "c = \\{\\vec{c_i} : (c_{i1}, c_{i2})\\}_i^{\\hat{N}_v}" + }, + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "type": "text", + "content": ". Then we generate 2D Gaussian distributions " + }, + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "type": "inline_equation", + "content": "\\mathcal{N}_i(c_i, \\sigma^2)" + }, + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "type": "text", + "content": " centered on the midpoint of each token, where " + }, + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "type": "text", + "content": " is the standard deviation and taken as the cube size (16, 16). Thus we will obtain the mixed Gaussian distribution " + }, + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "type": "inline_equation", + "content": "\\mathcal{P}(c, \\sigma^2) = \\sum_{i}^{\\hat{N}_v} \\mathcal{N}_i(\\vec{c_i}, \\sigma^2)" + }, + { + "bbox": [ + 47, + 229, + 288, + 357 + ], + "type": "text", + "content": " corresponding to the base frame. And the probability density function of the mixed Gaussian distribution is used to indicate the probability that the cube (token) is visible in the base frame." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 371, + 287, + 477 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 371, + 287, + 477 + ], + "spans": [ + { + "bbox": [ + 46, + 371, + 287, + 477 + ], + "type": "text", + "content": "Extract optical flows. We use both online and offline alternative methods to extract optical flow. Online method adapts RAFT [34] (the small version) to estimate the flows of the input video clip. Offline method applies the traditional TVL1 [53] algorithm to extract the dense flows between all adjacent frames in advance. We perform the consistent crop-resize-rescale operations when reading flows. Online and offline methods achieve the similar results. More details see in Sec. 4.2." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 479, + 287, + 503 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 479, + 287, + 503 + ], + "spans": [ + { + "bbox": [ + 46, + 479, + 287, + 503 + ], + "type": "text", + "content": "In practice, we only extract the flows " + }, + { + "bbox": [ + 46, + 479, + 287, + 503 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 46, + 479, + 287, + 503 + ], + "type": "text", + "content": " forward and backward from the base frame " + }, + { + "bbox": [ + 46, + 479, + 287, + 503 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_b" + }, + { + "bbox": [ + 46, + 479, + 287, + 503 + ], + "type": "text", + "content": ", i.e." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 88, + 509, + 287, + 525 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 88, + 509, + 287, + 525 + ], + "spans": [ + { + "bbox": [ + 88, + 509, + 287, + 525 + ], + "type": "interline_equation", + "content": "\\mathbf {F} = \\left\\{v _ {i \\rightarrow i + 1} \\right\\} _ {i = 1} ^ {b - 1} \\cup \\left\\{v _ {i \\rightarrow i - 1} \\right\\} _ {i = b + 1} ^ {T}, \\tag {1}", + "image_path": "2fb6dad725fb669bdacab939cd416422203de67e122bce6e0ab0e0ee0f840d9e.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 532, + 255, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 532, + 255, + 544 + ], + "spans": [ + { + "bbox": [ + 47, + 532, + 255, + 544 + ], + "type": "text", + "content": "where the flow " + }, + { + "bbox": [ + 47, + 532, + 255, + 544 + ], + "type": "inline_equation", + "content": "v_{i\\rightarrow j}" + }, + { + "bbox": [ + 47, + 532, + 255, + 544 + ], + "type": "text", + "content": " denotes the flow from " + }, + { + "bbox": [ + 47, + 532, + 255, + 544 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_i" + }, + { + "bbox": [ + 47, + 532, + 255, + 544 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 47, + 532, + 255, + 544 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_j" + }, + { + "bbox": [ + 47, + 532, + 255, + 544 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 558, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 558, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 558, + 288, + 713 + ], + "type": "text", + "content": "Warp masking maps with flows. We utilize the method of backward warping to generate the temporal consistent masking map of the video clip in a progressive manner. Forward warping " + }, + { + "bbox": [ + 46, + 558, + 288, + 713 + ], + "type": "inline_equation", + "content": "\\phi_F" + }, + { + "bbox": [ + 46, + 558, + 288, + 713 + ], + "type": "text", + "content": " and backward warping " + }, + { + "bbox": [ + 46, + 558, + 288, + 713 + ], + "type": "inline_equation", + "content": "\\phi_B" + }, + { + "bbox": [ + 46, + 558, + 288, + 713 + ], + "type": "text", + "content": " are two opposite patterns of warping. Both can be effectively employed to construct the masking volume from the initial masking map. Regrettably, forward warping suffers from hole or occlusion problems, that is, no flow vectors may pass to a certain pixel, or there may be multiple flow vectors passing to the same pixel. In contrast, backward warping maps the pixels of a given map one by one to individual locations. It's noteworthy that while backward warping doesn't escape from the issue of holes caused by mapping out of bounds, these holes are" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "content": "usually fewer than in forward warping and tend to occur at the boundaries of the map, thus causing less damage to the information distribution. For the holes caused by backward warping, we fill them with the values of " + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_b" + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "content": " at the same position to simulate the tube masking strategy." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 133, + 545, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 133, + 545, + 156 + ], + "spans": [ + { + "bbox": [ + 305, + 133, + 545, + 156 + ], + "type": "text", + "content": "Formally, given the flows " + }, + { + "bbox": [ + 305, + 133, + 545, + 156 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 305, + 133, + 545, + 156 + ], + "type": "text", + "content": " and the base frame masking volume " + }, + { + "bbox": [ + 305, + 133, + 545, + 156 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_b" + }, + { + "bbox": [ + 305, + 133, + 545, + 156 + ], + "type": "text", + "content": ", the mask map " + }, + { + "bbox": [ + 305, + 133, + 545, + 156 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_i" + }, + { + "bbox": [ + 305, + 133, + 545, + 156 + ], + "type": "text", + "content": " of " + }, + { + "bbox": [ + 305, + 133, + 545, + 156 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_i" + }, + { + "bbox": [ + 305, + 133, + 545, + 156 + ], + "type": "text", + "content": " can be constructed as" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 335, + 164, + 545, + 208 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 335, + 164, + 545, + 208 + ], + "spans": [ + { + "bbox": [ + 335, + 164, + 545, + 208 + ], + "type": "interline_equation", + "content": "\\mathbf {M} _ {i} = \\left\\{\\begin{array}{l l}\\phi_ {B} \\left(\\mathbf {M} _ {i + 1}, v _ {i \\rightarrow i + 1}\\right),&1 \\leq i < b\\\\\\mathbf {M} _ {b},&i = b\\\\\\phi_ {B} \\left(\\mathbf {M} _ {i - 1}, v _ {i \\rightarrow i - 1}\\right),&b < i \\leq T\\end{array}. \\right. \\tag {2}", + "image_path": "d6c59587f5909baed57e8e7337b71a4ec9f57be0c286143655595cf19644840b.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 217, + 545, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 217, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 304, + 217, + 545, + 266 + ], + "type": "text", + "content": "Subsequently, the entire masking volume " + }, + { + "bbox": [ + 304, + 217, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\mathbf{M} = \\{\\mathbf{M}_i\\}_{i=1}^T" + }, + { + "bbox": [ + 304, + 217, + 545, + 266 + ], + "type": "text", + "content": " of the video clip " + }, + { + "bbox": [ + 304, + 217, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\mathbf{I}" + }, + { + "bbox": [ + 304, + 217, + 545, + 266 + ], + "type": "text", + "content": " can be constructed by backward warping the flows " + }, + { + "bbox": [ + 304, + 217, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 304, + 217, + 545, + 266 + ], + "type": "text", + "content": " bidirectionally, originating from the base frame mask map " + }, + { + "bbox": [ + 304, + 217, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_b" + }, + { + "bbox": [ + 304, + 217, + 545, + 266 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 273, + 428, + 284 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 273, + 428, + 284 + ], + "spans": [ + { + "bbox": [ + 306, + 273, + 428, + 284 + ], + "type": "text", + "content": "3.3. Motion Guided MAE" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "spans": [ + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "text", + "content": "We build our MGMAE based on the above motion guided masking map. The temporal consistent masking volume indicates the probability that the corresponding position in the adjacent frame is visible under optical flow tracking. In order to suppress information leakage as much as possible, we sample the video tokens with the highest visible probability along the temporal dimension. Specifically, we first perform average pooling with kernel size " + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "inline_equation", + "content": "2 \\times 16 \\times 16" + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "text", + "content": " on the masking volume " + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "inline_equation", + "content": "\\mathbf{M}" + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "text", + "content": " to obtain the token-level masking volume " + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "inline_equation", + "content": "\\mathbf{M}'" + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "text", + "content": " of size " + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "inline_equation", + "content": "\\frac{T}{2} \\times \\frac{H}{16} \\times \\frac{W}{16}" + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "text", + "content": ". Then we pick the top-" + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "inline_equation", + "content": "\\hat{N}_v" + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "text", + "content": " locations of each mask map of size " + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "inline_equation", + "content": "\\frac{H}{16} \\times \\frac{W}{16}" + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "text", + "content": " along the temporal dimension and thus sample " + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "inline_equation", + "content": "N_v" + }, + { + "bbox": [ + 304, + 291, + 547, + 447 + ], + "type": "text", + "content": " corresponding video tokens as the unmasked visible tokens." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 448, + 547, + 532 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 448, + 547, + 532 + ], + "spans": [ + { + "bbox": [ + 304, + 448, + 547, + 532 + ], + "type": "text", + "content": "These sampled tokens according to our temporal consistent masking volume are fed into the asymmetric encoder-decoder for autoencoding based pre-training. The resulted pre-training framework is called Motion Guided Masked Autoencoder (MGMAE). The pre-trained model by our MGMAE is applied in the same way with the original Video-MAE for fine-tuning the downstream tasks." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 545, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 545, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 545, + 547, + 713 + ], + "type": "text", + "content": "Discussion. Previous works [35, 14] extended MAE to the video domain. They opted for the random (agnostic) masking and tube (space-only) masking strategies, respectively. Random masking introduces no explicit inductive bias about the video's space and time dimension. It aims to present a unified feature representation learning framework with minimal domain knowledge. We argue that although this idea is simple, time is inherently a distinctive dimension from space. By recognizing this, we could better leverage this prior information for enhanced video masked autoencoding. Tube masking assumes that a large area of the frame contains no or small motion, and thus masking the same position across frames could greatly reduce the information leakage risk. However, for motion-dominated video datasets such as" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13497" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 288, + 145 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 288, + 145 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 288, + 145 + ], + "type": "text", + "content": "Something-Something, this assumption will no longer hold true. Our proposed motion guided masking offers a more general and conceptually simple solution to take temporal correlation into account. It could be viewed as an adaptive video masking strategy and create more challenging yet meaningful tasks in video pre-training." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 156, + 128, + 170 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 156, + 128, + 170 + ], + "spans": [ + { + "bbox": [ + 47, + 156, + 128, + 170 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 177, + 105, + 189 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 177, + 105, + 189 + ], + "spans": [ + { + "bbox": [ + 47, + 177, + 105, + 189 + ], + "type": "text", + "content": "4.1. Dataset" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 195, + 290, + 411 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 195, + 290, + 411 + ], + "spans": [ + { + "bbox": [ + 46, + 195, + 290, + 411 + ], + "type": "text", + "content": "Following the original VideoMAE, we evaluate our MGMAE on Kinetics-400 (K400) [20] and Something-Something V2 (SSV2) [16]. K400 contains about 240k training videos and 20k validation videos from YouTube and the actions in K400 are usually coupled with specific objects or scenes, such as brushing teeth and playing piano. While SSV2 contains about 169k training videos and 25k validation videos, and the categories in SSV2 only care about specific motion patterns (e.g. push, pull). We first pre-train the video transformer with our MGMAE on the corresponding dataset for self-supervised representation learning. Then, we report the fine-tuning performance of pre-trained models on the target datasets for action recognition. In our MGMAE pretraining, we generally follow the setting and implementation of the original VideoMAE [35]. We use the RAFT [34] to extract optical flow due to its efficiency and accuracy in our MGMAE pre-training. The implementation details on our MGMAE could found in the appendix." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 420, + 148, + 432 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 420, + 148, + 432 + ], + "spans": [ + { + "bbox": [ + 47, + 420, + 148, + 432 + ], + "type": "text", + "content": "4.2. Ablation Studies" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 439, + 288, + 523 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 439, + 288, + 523 + ], + "spans": [ + { + "bbox": [ + 46, + 439, + 288, + 523 + ], + "type": "text", + "content": "In this subsection, we conduct in-depth ablation experiments on the choice in each step of our motion guided masking strategy. We pre-train the ViT-base model 800 epochs on the SSV2 dataset with 16 80G-A100 GPUs, and then fine-tune the encoder on the SSV2 dataset for action recognition. All models share the same training schedule and report the 2 clips " + }, + { + "bbox": [ + 46, + 439, + 288, + 523 + ], + "type": "inline_equation", + "content": "\\times 3" + }, + { + "bbox": [ + 46, + 439, + 288, + 523 + ], + "type": "text", + "content": " crops accuracy." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 540, + 287, + 612 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 540, + 287, + 612 + ], + "spans": [ + { + "bbox": [ + 46, + 540, + 287, + 612 + ], + "type": "text", + "content": "Choice of the base frame. In this study, we investigate the influence of base frame selection for initial masking generation process. We compare the middle frame as the based frame with either the first or a random frame, and the result is shown in Tab. 1a. It implies the middle frame is the best." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "content": "Warping method with optical flow. We compare two kinds of warping methods to align masking maps across frames as explained in Sec. 3.2. As previously mentioned above, the forward warping often leads to more severe occlusion and hole problems in the masking warping process. On the contrary, backward warping can effectively relieve this issue and ensure a more smooth masking warping. The" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 72, + 545, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 96 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 96 + ], + "type": "text", + "content": "result in Tab. 1b demonstrates that back warping contributes to better performance." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 113, + 547, + 209 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 113, + 547, + 209 + ], + "spans": [ + { + "bbox": [ + 304, + 113, + 547, + 209 + ], + "type": "text", + "content": "Sampling strategy of top-k visible tokens. We examine and compare the two sampling strategies to select the visible tokens based on our temporal consistent masking volume. Frame-level strategy samples the top-k locations for each frame independently, while clip-level strategy samples the top-k locations for the entire video jointly. As in Tab. 1c, the frame-level top-k sampling strategy achieves slightly better performance." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "spans": [ + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "text", + "content": "Masking initialization at the base frame. We ablate the choice of generating the initial masking at the base frame as shown in Tab. 1d. The token-level initialization method divides the mask map into " + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "inline_equation", + "content": "\\frac{H}{16} \\times \\frac{W}{16}" + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "text", + "content": " tokens of size " + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "inline_equation", + "content": "16 \\times 16" + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "text", + "content": ", and randomly sets " + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "inline_equation", + "content": "90\\%" + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "text", + "content": " tokens to 0 (representing masked) and " + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "text", + "content": " tokens to 1 (representing unmasked). The pixel-level initialization method randomly sets " + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "inline_equation", + "content": "90\\%" + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "text", + "content": " pixels to 0 and " + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 304, + 225, + 547, + 357 + ], + "type": "text", + "content": " pixels to 1. The initialization process of the mixed Gaussian method has been detailed in Sec. 3.2. The result demonstrates that the mixed Gaussian initialization method works the best." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 373, + 547, + 566 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 373, + 547, + 566 + ], + "spans": [ + { + "bbox": [ + 304, + 373, + 547, + 566 + ], + "type": "text", + "content": "Hole filling method. We investigate the various methods to handle the holes problem brought by the mapping out of bound in backward warping in Tab. 1e. To determine the real holes caused by warping, we set the 0 in the initial mask map to value " + }, + { + "bbox": [ + 304, + 373, + 547, + 566 + ], + "type": "inline_equation", + "content": "1e - 8" + }, + { + "bbox": [ + 304, + 373, + 547, + 566 + ], + "type": "text", + "content": ", and then the locations equal to 0 in new mask maps are treated as the holes. We experiment with 5 methods to fill the holes: Invisible method fills all holes with 0, while Visible method fills all holes with 1. Random method randomly fills the holes to 0 with probability of masking ratio " + }, + { + "bbox": [ + 304, + 373, + 547, + 566 + ], + "type": "inline_equation", + "content": "\\rho" + }, + { + "bbox": [ + 304, + 373, + 547, + 566 + ], + "type": "text", + "content": " and to 1 with probability of " + }, + { + "bbox": [ + 304, + 373, + 547, + 566 + ], + "type": "inline_equation", + "content": "1 - \\rho" + }, + { + "bbox": [ + 304, + 373, + 547, + 566 + ], + "type": "text", + "content": ". Previous map method fills holes using the values from the same spatial positions as the last generated mask map. Conversely, Tube method fills the holes with the value from the corresponding positions of the initial mask map, aligning with tube masking principles. We see that the tube method performs the best among all the methods." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 582, + 548, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 548, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 548, + 715 + ], + "type": "text", + "content": "Method of optical flow estimation. We evaluate the effect of different methods of optical flow estimation as shown in Tab. 1f. For the offline method, we use the TVL1 algorithm to extract optical flows in advance and it achieve a comparable accuracy to the online RAFT optical flow. Although VideoMAE is 1.3 times faster to train than MGMAE with RAFT-small (set to 6 testing iterations) to estimate flows, MGMAE has a clear advantage in terms of performance and reducing the risk of overfitting. We find that the offline method is not much faster than the online method because IO (reading optical flow from disk) will be a bottleneck to" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "13498" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 70, + 193, + 117 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 193, + 117 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 193, + 117 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 193, + 117 + ], + "type": "table", + "html": "
caseAcc@1Acc@5
first frame70.592.7
random frame70.692.9
middle frame71.093.1
", + "image_path": "6cad87dbcb6507cb62fd79e9aa704045d969ada48ffea97aaa97660e9bfa935c.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 47, + 121, + 200, + 153 + ], + "lines": [ + { + "bbox": [ + 47, + 121, + 200, + 153 + ], + "spans": [ + { + "bbox": [ + 47, + 121, + 200, + 153 + ], + "type": "text", + "content": "(a) Base frame selection. We perform ablation study to select the base frame as the first, random or the middle frame." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 50, + 171, + 192, + 217 + ], + "blocks": [ + { + "bbox": [ + 50, + 171, + 192, + 217 + ], + "lines": [ + { + "bbox": [ + 50, + 171, + 192, + 217 + ], + "spans": [ + { + "bbox": [ + 50, + 171, + 192, + 217 + ], + "type": "table", + "html": "
caseAcc@1Acc@5
token rand.70.993.0
pixel rand.70.893.0
mixed Gauss71.093.1
", + "image_path": "e139dcd059024703e4b1c7da324c0330bd051464103dde11347468da5145bb93.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 47, + 221, + 200, + 265 + ], + "lines": [ + { + "bbox": [ + 47, + 221, + 200, + 265 + ], + "spans": [ + { + "bbox": [ + 47, + 221, + 200, + 265 + ], + "type": "text", + "content": "(d) Masking initialization. We compare three methods to generate the masking map in the base frame. Two binary random methods and one mixed Gaussian method." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 214, + 76, + 358, + 110 + ], + "blocks": [ + { + "bbox": [ + 214, + 76, + 358, + 110 + ], + "lines": [ + { + "bbox": [ + 214, + 76, + 358, + 110 + ], + "spans": [ + { + "bbox": [ + 214, + 76, + 358, + 110 + ], + "type": "table", + "html": "
caseAcc@1Acc@5
forward70.592.9
backward71.093.1
", + "image_path": "5eb223198a89e329f2eb5b4107c77f5d530482ebb67804f74e8870d7b13e46c1.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 212, + 115, + 365, + 148 + ], + "lines": [ + { + "bbox": [ + 212, + 115, + 365, + 148 + ], + "spans": [ + { + "bbox": [ + 212, + 115, + 365, + 148 + ], + "type": "text", + "content": "(b) Warping method. We choose forward or backward warping method for aligning masking maps." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 225, + 160, + 365, + 227 + ], + "blocks": [ + { + "bbox": [ + 225, + 160, + 365, + 227 + ], + "lines": [ + { + "bbox": [ + 225, + 160, + 365, + 227 + ], + "spans": [ + { + "bbox": [ + 225, + 160, + 365, + 227 + ], + "type": "table", + "html": "
caseAcc@1Acc@5
random70.892.9
invisible70.792.8
visible70.893.1
previous map70.692.8
tube71.093.1
", + "image_path": "326b12634022fe9b945532492ee74e23974c4422e028d4a0dc43b5123eb153ff.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 220, + 232, + 372, + 277 + ], + "lines": [ + { + "bbox": [ + 220, + 232, + 372, + 277 + ], + "spans": [ + { + "bbox": [ + 220, + 232, + 372, + 277 + ], + "type": "text", + "content": "(e) Hole filling. We choose some baseline choices to fill the value in the hole place caused by warping. We also use the tube filling consistent with the tube masking." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 395, + 76, + 539, + 110 + ], + "blocks": [ + { + "bbox": [ + 395, + 76, + 539, + 110 + ], + "lines": [ + { + "bbox": [ + 395, + 76, + 539, + 110 + ], + "spans": [ + { + "bbox": [ + 395, + 76, + 539, + 110 + ], + "type": "table", + "html": "
caseAcc@1Acc@5
clip-level70.792.9
frame-level71.093.1
", + "image_path": "42bc10fb2fcb151fa7cb116360ceaa5ad336b07b097133b0fc7fb2b7a9ecdd63.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 393, + 116, + 547, + 159 + ], + "lines": [ + { + "bbox": [ + 393, + 116, + 547, + 159 + ], + "spans": [ + { + "bbox": [ + 393, + 116, + 547, + 159 + ], + "type": "text", + "content": "(c) Sampling strategy. We perform a study to choose the visible token generation strategy based on motion guided masking volume." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 395, + 166, + 542, + 221 + ], + "blocks": [ + { + "bbox": [ + 395, + 166, + 542, + 221 + ], + "lines": [ + { + "bbox": [ + 395, + 166, + 542, + 221 + ], + "spans": [ + { + "bbox": [ + 395, + 166, + 542, + 221 + ], + "type": "table", + "html": "
methodtimeAcc@1
None (VideoMAE)32 h69.6
TVL1 (offline)41 h71.2
RAFT with 6 iters43 h71.3
RAFT with 12 iters56 h71.0
", + "image_path": "bc1e4d0a6e8ec7a1d24399cdfe75c457f7fbcbc23252e79a38bb215c32f6a5e2.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 393, + 227, + 547, + 271 + ], + "lines": [ + { + "bbox": [ + 393, + 227, + 547, + 271 + ], + "spans": [ + { + "bbox": [ + 393, + 227, + 547, + 271 + ], + "type": "text", + "content": "(f) Method of optical flow estimation. We perform the ablation study to investigate the influence of different methods of optical flow estimation." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_footnote" + }, + { + "bbox": [ + 46, + 285, + 547, + 346 + ], + "lines": [ + { + "bbox": [ + 46, + 285, + 547, + 346 + ], + "spans": [ + { + "bbox": [ + 46, + 285, + 547, + 346 + ], + "type": "text", + "content": "Table 1: Parts of the ablation experiments on the Something-Something V2 dataset. Our MGMAE pre-training is implemented with the 16-frame vanilla ViT-B backbone. All models are pre-trained for 800 epochs and the masking ratio is " + }, + { + "bbox": [ + 46, + 285, + 547, + 346 + ], + "type": "inline_equation", + "content": "\\rho = 90\\%" + }, + { + "bbox": [ + 46, + 285, + 547, + 346 + ], + "type": "text", + "content": ". The inference protocol is to report the fine-tuning action recognition accuracy with 2 clips " + }, + { + "bbox": [ + 46, + 285, + 547, + 346 + ], + "type": "inline_equation", + "content": "\\times" + }, + { + "bbox": [ + 46, + 285, + 547, + 346 + ], + "type": "text", + "content": " 3 crops. The default choice for our model is colored in gray. Although the default setting is not optimal in terms of the method of optical flow estimation, we believe that this does not affect the conclusions of the ablation experiments." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 368, + 287, + 403 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 368, + 287, + 403 + ], + "spans": [ + { + "bbox": [ + 46, + 368, + 287, + 403 + ], + "type": "text", + "content": "increase the training speed. Note that our default setting is not optimal, but the conclusions drawn in other ablation experiments should not be impacted." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 420, + 289, + 661 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 420, + 289, + 661 + ], + "spans": [ + { + "bbox": [ + 46, + 420, + 289, + 661 + ], + "type": "text", + "content": "Masking ratio. The performance of MGMAE highlights the importance of improving masking strategies even at high masking rates (e.g. " + }, + { + "bbox": [ + 46, + 420, + 289, + 661 + ], + "type": "inline_equation", + "content": "90\\%" + }, + { + "bbox": [ + 46, + 420, + 289, + 661 + ], + "type": "text", + "content": "). However, after applying MGMAE, it remains questionable whether such high masking rates are still necessary. Indeed, as pointed out by [35, 14], blindly increasing the masking rate could potentially degrade the model performance. Our ablation study presented in Fig. 3 shows that sustaining a extremely high masking rate of over " + }, + { + "bbox": [ + 46, + 420, + 289, + 661 + ], + "type": "inline_equation", + "content": "80\\%" + }, + { + "bbox": [ + 46, + 420, + 289, + 661 + ], + "type": "text", + "content": " is also crucial even with MGMAE. We think the video background and large objects mainly drive the need for a high masking ratio. Video backgrounds are often wide and simple. If the mask ratio is not high enough, the model can still rebuild pixels from other background parts, even if nearby frames mask similar sections. For large objects, a lower ratio might let the model use the texture from a different part of the object when another section is masked. It can also be observed that MGMAE performs optimally with " + }, + { + "bbox": [ + 46, + 420, + 289, + 661 + ], + "type": "inline_equation", + "content": "85\\%" + }, + { + "bbox": [ + 46, + 420, + 289, + 661 + ], + "type": "text", + "content": " masking ratio, but " + }, + { + "bbox": [ + 46, + 420, + 289, + 661 + ], + "type": "inline_equation", + "content": "90\\%" + }, + { + "bbox": [ + 46, + 420, + 289, + 661 + ], + "type": "text", + "content": " still seems to be a decent choice when considering the trade-off between training efficiency and performance." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 46, + 677, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 289, + 715 + ], + "type": "text", + "content": "Exposure of masked objects. Another proposition worth considering is whether occasional exposure of masked objects help with masked video modeling pre-train. We com" + } + ] + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 316, + 369, + 541, + 510 + ], + "blocks": [ + { + "bbox": [ + 316, + 369, + 541, + 510 + ], + "lines": [ + { + "bbox": [ + 316, + 369, + 541, + 510 + ], + "spans": [ + { + "bbox": [ + 316, + 369, + 541, + 510 + ], + "type": "image", + "image_path": "7570868376420a105af45ff48a1d3f5c3c7f5df0ee119824359108b3acda2e9a.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 329, + 526, + 521, + 538 + ], + "lines": [ + { + "bbox": [ + 329, + 526, + 521, + 538 + ], + "spans": [ + { + "bbox": [ + 329, + 526, + 521, + 538 + ], + "type": "text", + "content": "Figure 3: The effect of masking ratio on SSV2." + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_caption" + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 562, + 547, + 635 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 562, + 547, + 635 + ], + "spans": [ + { + "bbox": [ + 304, + 562, + 547, + 635 + ], + "type": "text", + "content": "pleted a complementary experiment. Specifically, after building the masking volume, we add Gaussian noise on the mask map of one randomly selected frame. This modification may provide a chance for masked objects to be exposed. The results showed an accuracy of " + }, + { + "bbox": [ + 304, + 562, + 547, + 635 + ], + "type": "inline_equation", + "content": "71.2\\%" + }, + { + "bbox": [ + 304, + 562, + 547, + 635 + ], + "type": "text", + "content": ", slightly higher than the default setting of " + }, + { + "bbox": [ + 304, + 562, + 547, + 635 + ], + "type": "inline_equation", + "content": "71.0\\%" + }, + { + "bbox": [ + 304, + 562, + 547, + 635 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 306, + 646, + 517, + 658 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 646, + 517, + 658 + ], + "spans": [ + { + "bbox": [ + 306, + 646, + 517, + 658 + ], + "type": "text", + "content": "4.3. Main Results and Visualization Analysis" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "content": "After the detailed ablation study on the design of MGMAE, we further perform a deeper analysis by comparing it with the original VideoMAE. We also provide some intermediate visualization results to illustrate the motion guided" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13499" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 55, + 70, + 280, + 151 + ], + "blocks": [ + { + "bbox": [ + 55, + 70, + 280, + 151 + ], + "lines": [ + { + "bbox": [ + 55, + 70, + 280, + 151 + ], + "spans": [ + { + "bbox": [ + 55, + 70, + 280, + 151 + ], + "type": "table", + "html": "
ModelEpochsK400SSV2
VideoMAE800 / 8000.58750.5278
MGMAE0.64620.5820
Δ loss-Δ + 0.0605Δ + 0.0542
VideoMAE1600 / 24000.58090.5122
MGMAE0.63780.5659
Δ loss-Δ + 0.0569Δ + 0.0537
", + "image_path": "4b26bc8dbdc7c416f6dfc1823c6c3b193513936bbfccf80e5a2a524b9b8d0957.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 61, + 194, + 273, + 277 + ], + "blocks": [ + { + "bbox": [ + 47, + 159, + 288, + 182 + ], + "lines": [ + { + "bbox": [ + 47, + 159, + 288, + 182 + ], + "spans": [ + { + "bbox": [ + 47, + 159, + 288, + 182 + ], + "type": "text", + "content": "Table 2: Pre-train loss comparison of MGMAE and Video-MAE." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 61, + 194, + 273, + 277 + ], + "lines": [ + { + "bbox": [ + 61, + 194, + 273, + 277 + ], + "spans": [ + { + "bbox": [ + 61, + 194, + 273, + 277 + ], + "type": "table", + "html": "
ModelEpochsK400SSV2
VideoMAE800 / 80080.069.6
MGMAE81.271.0
Δ Acc@1-Δ + 1.2%Δ + 1.4%
VideoMAE1600 / 240081.570.8
MGMAE81.872.3
Δ Acc@1-Δ + 0.3%Δ + 1.5%
", + "image_path": "8341ca3baa4f7b190ec1c1867e0fa172ff68a22adc9bfdcfc8e2f5e1f4d793c9.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 285, + 286, + 297 + ], + "lines": [ + { + "bbox": [ + 47, + 285, + 286, + 297 + ], + "spans": [ + { + "bbox": [ + 47, + 285, + 286, + 297 + ], + "type": "text", + "content": "Table 3: Accuracy comparison of MGMAE and VideoMAE." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "type": "image", + "bbox": [ + 48, + 310, + 282, + 430 + ], + "blocks": [ + { + "bbox": [ + 48, + 310, + 282, + 430 + ], + "lines": [ + { + "bbox": [ + 48, + 310, + 282, + 430 + ], + "spans": [ + { + "bbox": [ + 48, + 310, + 282, + 430 + ], + "type": "image", + "image_path": "905abaed5e2b8fe97517709580fbe4be655e20a936c6e87ce5cb5e75ca0ee03b.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 439, + 288, + 464 + ], + "lines": [ + { + "bbox": [ + 47, + 439, + 288, + 464 + ], + "spans": [ + { + "bbox": [ + 47, + 439, + 288, + 464 + ], + "type": "text", + "content": "Figure 4: Comparative Accuracy of MGMAE and Video-MAE by Class." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 487, + 121, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 487, + 121, + 498 + ], + "spans": [ + { + "bbox": [ + 47, + 487, + 121, + 498 + ], + "type": "text", + "content": "sampling process." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 516, + 287, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 516, + 287, + 647 + ], + "spans": [ + { + "bbox": [ + 46, + 516, + 287, + 647 + ], + "type": "text", + "content": "Pre-train loss implies a more challenging task. The core design of MGMAE is to dynamically sample the positions of masked token under the guidance of optical flows and aims at increasing the difficulty of the reconstruction task. As can be seen in Tab. 2, the pre-train loss of MGMAE is always larger than that of VideoMAE by more than 0.05. This loss gap implies motion guided masking further suppresses information leakage and indeed constructs a more challenging mask-reconstruct pretext task for masked video modeling. This more difficult task would like to encourage learning more effective representations." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 665, + 286, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 286, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 286, + 714 + ], + "type": "text", + "content": "Detailed breakdown of comparison between MGMAE and VideoMAE. To understand the distinct impacts of the MGMAE and VideoMAE masking strategies on video model pre-training, we delved deeper into the per-class accuracy" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 306, + 69, + 545, + 244 + ], + "blocks": [ + { + "bbox": [ + 306, + 69, + 545, + 244 + ], + "lines": [ + { + "bbox": [ + 306, + 69, + 545, + 244 + ], + "spans": [ + { + "bbox": [ + 306, + 69, + 545, + 244 + ], + "type": "image", + "image_path": "85b3fc91297b9d7f8e516955684dec58615e306756a751666d116051d95a8fd7.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 251, + 547, + 323 + ], + "lines": [ + { + "bbox": [ + 305, + 251, + 547, + 323 + ], + "spans": [ + { + "bbox": [ + 305, + 251, + 547, + 323 + ], + "type": "text", + "content": "Figure 5: Visualization of the video in SSV2 validation set. We present our motion guided mask maps and the reconstructed images. From top to bottom, the original images, the x-direction flows, the y-direction flows, the motion guided mask maps, the masked images and the reconstructed images." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 347, + 547, + 383 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 347, + 547, + 383 + ], + "spans": [ + { + "bbox": [ + 305, + 347, + 547, + 383 + ], + "type": "text", + "content": "variations between the two. Fig. 4 showcases the 29 categories with the most pronounced differences in classification accuracy between MGMAE and VideoMAE." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 402, + 547, + 569 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 402, + 547, + 569 + ], + "spans": [ + { + "bbox": [ + 305, + 402, + 547, + 569 + ], + "type": "text", + "content": "MGMAE: a more effective video representation learner. MGMAE benefits greatly from the harder task constructed by our motion guided masking strategy. On the one hand, the model has to encode the relationship between visible and invisible tokens harder, which can better guide the model training. On the other hand, the suppression of information leakage may well reduce the overfitting risk of the pretraining, and thus the model can be pre-trained much longer. As shown in Tab. 3, MGMAE consistently maintains an obvious fine-tuning performance gap with VideoMAE on the motion-centric SSV2 dataset (1.4% at 800 epochs and 1.5% at 2400 epochs) and also has some improvement on the scene-centric Kinetics-400 dataset (1.2% at 800 epochs and 0.3% at 1600 epochs)." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 588, + 547, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 588, + 547, + 647 + ], + "spans": [ + { + "bbox": [ + 305, + 588, + 547, + 647 + ], + "type": "text", + "content": "Visualization. We randomly seletec a video clip in SSV2 validation set and show its reconstruction example in Fig. 5. We can see that the mask map changes with object movements, which makes it more difficult for the model to reconstruct the original video." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 658, + 542, + 670 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 658, + 542, + 670 + ], + "spans": [ + { + "bbox": [ + 306, + 658, + 542, + 670 + ], + "type": "text", + "content": "4.4. Comparison with the state-of-the-art methods" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 677, + 547, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 677, + 547, + 712 + ], + "spans": [ + { + "bbox": [ + 306, + 677, + 547, + 712 + ], + "type": "text", + "content": "We compare our approach with the previous state-of-the-art methods on the Kinetics-400 and Something-Something V2 datasets. The results are shown in Table 5 and Table 4." + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13500" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 99, + 69, + 492, + 274 + ], + "blocks": [ + { + "bbox": [ + 99, + 69, + 492, + 274 + ], + "lines": [ + { + "bbox": [ + 99, + 69, + 492, + 274 + ], + "spans": [ + { + "bbox": [ + 99, + 69, + 492, + 274 + ], + "type": "table", + "html": "
MethodBackbonePre-train dataFramesGFLOPsParamAcc@1Acc@5
TEINetEn[24]ResNet50×28+1699×10×35066.5N/A
TANetEn[26]ResNet50×2ImageNet-1K8+1699×2×35166.090.1
TDEN[43]ResNet101×28+16198×1×38869.692.2
SlowFast [15]ResNet101Kinetics-4008+32106×1×35363.187.6
MViTv1 [13]MViTv1-B64455×1×33767.790.9
TimeSformer [5]ViT-BImageNet-21K8196×1×312159.5N/A
TimeSformer [5]ViT-L645549×1×343062.4N/A
ViViT FE [1]ViT-LIN-21K+K40032995×4×3N/A65.989.9
Motionformer [28]ViT-B16370×1×310966.590.1
Motionformer [28]ViT-L321185×1×338268.191.2
Video Swin [25]Swin-B32321×1×38869.692.7
VIMPAC [32]ViT-LHowTo100M+DALLE w/o label10N/A×10×330768.1N/A
BEVT [45]Swin-BIN-1K+K400+DALLE w/o label32321×1×38870.6N/A
MAE-ST1600e [14]ViT-LKinetics-400 w/o label16597×1×330572.193.9
MaskFeat↑312 [48]MViT-LKinetics-600402828×1×321875.095.0
VideoMAE800e [35]ViT-BSSV2 w/o label16180×2×38769.692.0
VideoMAE2400e [35]ViT-B16180×2×38770.892.4
MGMAE800eViT-BSSV2 w/o label16180×2×38771.093.1
MGMAE2400eViT-B16180×2×38772.393.5
", + "image_path": "e350b3dc7071c9cd187a75354be9c76cf303ec32572bda79dfe5112fd66e0f52.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 109, + 297, + 483, + 481 + ], + "blocks": [ + { + "bbox": [ + 47, + 277, + 545, + 289 + ], + "lines": [ + { + "bbox": [ + 47, + 277, + 545, + 289 + ], + "spans": [ + { + "bbox": [ + 47, + 277, + 545, + 289 + ], + "type": "text", + "content": "Table 4: Comparison on the Something-Something V2 dataset. We only list the results obtained with the similar backbones." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 109, + 297, + 483, + 481 + ], + "lines": [ + { + "bbox": [ + 109, + 297, + 483, + 481 + ], + "spans": [ + { + "bbox": [ + 109, + 297, + 483, + 481 + ], + "type": "table", + "html": "
MethodBackbonePre-train dataFramesGFLOPsParamAcc@1Acc@5
NL I3D [47]ResNet101ImageNet-1K128359×10×36277.393.3
TANet [26]ResNet15216242×4×35979.394.1
TDEN[43]ResNet1018+16198×10×38879.494.4
TimeSformer [5]ViT-LImageNet-21K968353×1×343080.794.7
ViViT FE [1]ViT-L1283980×1×3N/A81.793.8
Motionformer [28]ViT-L321185×10×338280.294.8
Video Swin [25]Swin-B32282×4×38882.795.5
VIMPAC [32]ViT-LHowTo100M+DALLE w/o label10N/A×10×330777.4N/A
BEVT [45]Swin-BIN-1K+DALLE w/o label32282×4×38880.6N/A
ip-CSN [37]ResNet152None32109×10×33377.892.8
SlowFast [15]R101+NL16+64234×10×36079.893.9
MViTv1 [13]MViTv1-B32170×5×13780.294.4
MAE-ST1600e [14]ViT-BKinetics-400 w/o label16180×7×38781.394.9
VideoMAE800e [35]ViT-B16180×5×38780.094.4
VideoMAE1600e [35]ViT-B16180×5×38781.595.1
MGMAE800eViT-BKinetics-400 w/o label16180×5×38781.294.9
MGMAE1600eViT-B16180×5×38781.895.0
", + "image_path": "3143703498d3f81fc62d4f53c7c05cc26f741e39eacbfc0ce8ec31abf9784d95.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 69, + 488, + 523, + 500 + ], + "lines": [ + { + "bbox": [ + 69, + 488, + 523, + 500 + ], + "spans": [ + { + "bbox": [ + 69, + 488, + 523, + 500 + ], + "type": "text", + "content": "Table 5: Comparison on the Kinetics-400 dataset. We only list the results obtained with the similar backbones." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 514, + 288, + 646 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 514, + 288, + 646 + ], + "spans": [ + { + "bbox": [ + 46, + 514, + 288, + 646 + ], + "type": "text", + "content": "For a fair comparison, we mainly list the results with similar computational cost. On the Something-Something V2 dataset, our MGMAE with ViT-B backbone achieves a performance of " + }, + { + "bbox": [ + 46, + 514, + 288, + 646 + ], + "type": "inline_equation", + "content": "72.3\\%" + }, + { + "bbox": [ + 46, + 514, + 288, + 646 + ], + "type": "text", + "content": " when trained for 2400 epochs, which outperforms the original VideoMAE by " + }, + { + "bbox": [ + 46, + 514, + 288, + 646 + ], + "type": "inline_equation", + "content": "1.5\\%" + }, + { + "bbox": [ + 46, + 514, + 288, + 646 + ], + "type": "text", + "content": ". On the Kinetics-400 dataset, our MGMAE obtains slightly better performance than the original VideoMAE. The small performance improvement might be ascribed to the fact that Kinetics-400 is a scene-centric action recognition benchmark and motion information is less important compared with the Something-Something dataset." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 657, + 119, + 669 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 657, + 119, + 669 + ], + "spans": [ + { + "bbox": [ + 47, + 657, + 119, + 669 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "content": "In this paper, we have proposed the Motion Guided Masked Autoencoders (MGMAE), which adapts the motion guided masking strategy to dynamically sample the" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 514, + 547, + 610 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 514, + 547, + 610 + ], + "spans": [ + { + "bbox": [ + 304, + 514, + 547, + 610 + ], + "type": "text", + "content": "unmasked visible tokens under the guidance of flows, thus suppressing information leakage to build a more challenging task for masked video pre-training. Experiments have shown that MGMAE has good performance and maintains a high-performance advantage over the previous methods under fair comparison. In addition, our strategy also reduces the risk of pre-training overfitting, which allows the model to benefit from longer pre-training." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 629, + 548, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 548, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 548, + 715 + ], + "type": "text", + "content": "Acknowledgements. This work is supported by the National Key R&D Program of China (No. 2022ZD0160900, No.2022ZD0160100), the National Natural Science Foundation of China (No. 62076119, No. 61921006), Shanghai Committee of Science and Technology (Grant No. 21DZ1100100), and Collaborative Innovation Center of Novel Software Technology and Industrialization." + } + ] + } + ], + "index": 8 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13501" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 134 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 134 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 134 + ], + "type": "text", + "content": "[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In IEEE/CVF International Conference on Computer Vision, 2021. 1, 9" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 135, + 288, + 201 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 135, + 288, + 201 + ], + "spans": [ + { + "bbox": [ + 53, + 135, + 288, + 201 + ], + "type": "text", + "content": "[2] Wele Gedara Chaminda Bandara, Naman Patel, Ali Gholami, Mehdi Nikkhah, Motilal Agrawal, and Vishal M Patel. Adamae: Adaptive masking for efficient spatiotemporal learning with masked autoencoders. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14507-14517, 2023. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 202, + 288, + 235 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 202, + 288, + 235 + ], + "spans": [ + { + "bbox": [ + 53, + 202, + 288, + 235 + ], + "type": "text", + "content": "[3] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. BEit: BERT pre-training of image transformers. In International Conference on Learning Representations, 2022. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 236, + 288, + 289 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 236, + 288, + 289 + ], + "spans": [ + { + "bbox": [ + 53, + 236, + 288, + 289 + ], + "type": "text", + "content": "[4] Wenbo Bao, Wei-Sheng Lai, Chao Ma, Xiaoyun Zhang, Zhiyong Gao, and Ming-Hsuan Yang. Depth-aware video frame interpolation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3703-3712, 2019. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 291, + 288, + 324 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 291, + 288, + 324 + ], + "spans": [ + { + "bbox": [ + 53, + 291, + 288, + 324 + ], + "type": "text", + "content": "[5] Gedas Bertasius, Heng Wang, and Lorenzo Torresani. Is space-time attention all you need for video understanding? In International Conference on Machine Learning, 2021. 1, 3, 9" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 325, + 288, + 379 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 325, + 288, + 379 + ], + "spans": [ + { + "bbox": [ + 53, + 325, + 288, + 379 + ], + "type": "text", + "content": "[6] Kelvin CK Chan, Shangchen Zhou, Xiangyu Xu, and Chen Change Loy. Basicvsr++: Improving video superresolution with enhanced propagation and alignment. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5972-5981, 2022. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 380, + 288, + 423 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 380, + 288, + 423 + ], + "spans": [ + { + "bbox": [ + 53, + 380, + 288, + 423 + ], + "type": "text", + "content": "[7] Mark Chen, Alec Radford, Rewon Child, Jeffrey Wu, Heewoo Jun, David Luan, and Ilya Sutskever. Generative pretraining from pixels. In International Conference on Machine Learning, 2020. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 425, + 288, + 468 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 425, + 288, + 468 + ], + "spans": [ + { + "bbox": [ + 53, + 425, + 288, + 468 + ], + "type": "text", + "content": "[8] Yutao Cui, Cheng Jiang, Limin Wang, and Gangshan Wu. Mixformer: End-to-end tracking with iterative mixed attention. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 469, + 288, + 524 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 469, + 288, + 524 + ], + "spans": [ + { + "bbox": [ + 53, + 469, + 288, + 524 + ], + "type": "text", + "content": "[9] Navneet Dalal and Bill Triggs. Histograms of oriented gradients for human detection. In 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR 2005), 20-26 June 2005, San Diego, CA, USA, pages 886-893. IEEE Computer Society, 2005. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 525, + 288, + 557 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 525, + 288, + 557 + ], + "spans": [ + { + "bbox": [ + 48, + 525, + 288, + 557 + ], + "type": "text", + "content": "[10] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In CVPR, pages 248–255. IEEE Computer Society, 2009. 1" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 558, + 288, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 558, + 288, + 602 + ], + "spans": [ + { + "bbox": [ + 48, + 558, + 288, + 602 + ], + "type": "text", + "content": "[11] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In North American Chapter of the Association for Computational Linguistics, 2019. 1, 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 603, + 288, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 603, + 288, + 668 + ], + "spans": [ + { + "bbox": [ + 48, + 603, + 288, + 668 + ], + "type": "text", + "content": "[12] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2021. 1, 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 669, + 288, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 669, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 669, + 288, + 713 + ], + "type": "text", + "content": "[13] Haoqi Fan, Bo Xiong, Karttikeya Mangalam, Yanghao Li, Zhicheng Yan, Jitendra Malik, and Christoph Feichtenhofer. Multiscale vision transformers. In IEEE/CVF International Conference on Computer Vision, 2021. 9" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 307, + 73, + 547, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 547, + 116 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 547, + 116 + ], + "type": "text", + "content": "[14] Christoph Feichtenhofer, Haoqi Fan, Yanghao Li, and Kaiming He. Masked autoencoders as spatiotemporal learners. In Advances in Neural Information Processing Systems, 2022. 1, 2, 4, 5, 7, 9" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 118, + 547, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 547, + 161 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 547, + 161 + ], + "type": "text", + "content": "[15] Christoph Feichtenhofer, Haoqi Fan, Jitendra Malik, and Kaiming He. Slowfast networks for video recognition. In IEEE/CVF International Conference on Computer Vision, 2019. 9" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 163, + 547, + 250 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 163, + 547, + 250 + ], + "spans": [ + { + "bbox": [ + 308, + 163, + 547, + 250 + ], + "type": "text", + "content": "[16] Raghav Goyal, Samira Ebrahimi Kahou, Vincent Michalski, Joanna Materzynska, Susanne Westphal, Heuna Kim, Valentin Haenel, Ingo Fründ, Peter Yianilos, Moritz Mueller-Freitag, Florian Hoppe, Christian Thurau, Ingo Bax, and Roland Memisevic. The \"something something\" video database for learning and evaluating visual common sense. In IEEE/CVF International Conference on Computer Vision, 2017. 2, 6" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 251, + 546, + 296 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 251, + 546, + 296 + ], + "spans": [ + { + "bbox": [ + 308, + 251, + 546, + 296 + ], + "type": "text", + "content": "[17] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1, 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 297, + 546, + 341 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 297, + 546, + 341 + ], + "spans": [ + { + "bbox": [ + 308, + 297, + 546, + 341 + ], + "type": "text", + "content": "[18] Zhewei Huang, Tianyuan Zhang, Wen Heng, Boxin Shi, and Shuchang Zhou. Rife: Real-time intermediate flow estimation for video frame interpolation. arXiv preprint arXiv:2011.06294, 2020.3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 342, + 546, + 386 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 342, + 546, + 386 + ], + "spans": [ + { + "bbox": [ + 308, + 342, + 546, + 386 + ], + "type": "text", + "content": "[19] Sunil Hwang, Jaehong Yoon, Youngwan Lee, and Sung Ju Hwang. Efficient video representation learning via masked video modeling with motion-centric token selection. arXiv preprint arXiv:2211.10636, 2022. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 388, + 546, + 442 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 388, + 546, + 442 + ], + "spans": [ + { + "bbox": [ + 308, + 388, + 546, + 442 + ], + "type": "text", + "content": "[20] Will Kay, Joao Carreira, Karen Simonyan, Brian Zhang, Chloe Hillier, Sudheendra Vijayanarasimhan, Fabio Viola, Tim Green, Trevor Back, Paul Natsev, Mustafa Suleyman, and Andrew Zisserman. The kinetics human action video dataset. arXiv preprint arXiv:1705.06950, 2017. 2, 6" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 444, + 547, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 444, + 547, + 498 + ], + "spans": [ + { + "bbox": [ + 308, + 444, + 547, + 498 + ], + "type": "text", + "content": "[21] Heeseung Kwon, Manjin Kim, Suha Kwak, and Minsu Cho. Motionsqueeze: Neural motion feature learning for video understanding. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XVI 16, pages 345-362. Springer, 2020. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 500, + 546, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 500, + 546, + 533 + ], + "spans": [ + { + "bbox": [ + 308, + 500, + 546, + 533 + ], + "type": "text", + "content": "[22] Yan Li, Bin Ji, Xintian Shi, Jianguo Zhang, Bin Kang, and Limin Wang. TEA: temporal excitation and aggregation for action recognition. In CVPR, pages 906-915, 2020. 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 534, + 546, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 534, + 546, + 588 + ], + "spans": [ + { + "bbox": [ + 308, + 534, + 546, + 588 + ], + "type": "text", + "content": "[23] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In IEEE/CVF International Conference on Computer Vision, 2021. 1" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 590, + 547, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 590, + 547, + 644 + ], + "spans": [ + { + "bbox": [ + 308, + 590, + 547, + 644 + ], + "type": "text", + "content": "[24] Zhaoyang Liu, Donghao Luo, Yabiao Wang, Limin Wang, Ying Tai, Chengjie Wang, Jilin Li, Feiyue Huang, and Tong Lu. TEINet: Towards an efficient architecture for video recognition. In Proceedings of the AAAI Conference on Artificial Intelligence, 2020. 9" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 646, + 546, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 646, + 546, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 646, + 546, + 689 + ], + "type": "text", + "content": "[25] Ze Liu, Jia Ning, Yue Cao, Yixuan Wei, Zheng Zhang, Stephen Lin, and Han Hu. Video swim transformer. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 9" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 691, + 546, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 691, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 691, + 546, + 713 + ], + "type": "text", + "content": "[26] Zhaoyang Liu, Limin Wang, Wayne Wu, Chen Qian, and Tong Lu. Tam: Temporal adaptive module for video recognition." + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "13502" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 66, + 72, + 288, + 94 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 288, + 94 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 288, + 94 + ], + "type": "text", + "content": "In IEEE/CVF International Conference on Computer Vision, 2021. 9" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 95, + 288, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 95, + 288, + 139 + ], + "spans": [ + { + "bbox": [ + 48, + 95, + 288, + 139 + ], + "type": "text", + "content": "[27] Deepak Pathak, Philipp Krahenbuhl, Jeff Donahue, Trevor Darrell, and Alexei A. Efros. Context encoders: Feature learning by inpainting. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2016. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 140, + 288, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 140, + 288, + 194 + ], + "spans": [ + { + "bbox": [ + 48, + 140, + 288, + 194 + ], + "type": "text", + "content": "[28] Mandela Patrick, Dylan Campbell, Yuki M. Asano, Ishaan Misra, Florian Metze, Christoph Feichtenhofer, Andrea Vedaldi, and João F. Henriques. Keeping your eye on the ball: Trajectory attention in video transformers. In NeurIPS, pages 12493-12506, 2021. 3, 9" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 195, + 288, + 237 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 195, + 288, + 237 + ], + "spans": [ + { + "bbox": [ + 48, + 195, + 288, + 237 + ], + "type": "text", + "content": "[29] Zhiwu Qing, Shiwei Zhang, Ziyuan Huang, Xiang Wang, Yuehuan Wang, Yiliang Lv, Changxin Gao, and Nong Sang. Mar: Masked autoencoders for efficient action recognition. IEEE Transactions on Multimedia, 2023. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 239, + 288, + 272 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 239, + 288, + 272 + ], + "spans": [ + { + "bbox": [ + 48, + 239, + 288, + 272 + ], + "type": "text", + "content": "[30] Alec Radford, Jeff Wu, Rewon Child, David Luan, Dario Amodei, and Ilya Sutskever. Language models are unsupervised multitask learners. OpenAI blog, 2019. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 273, + 288, + 304 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 273, + 288, + 304 + ], + "spans": [ + { + "bbox": [ + 48, + 273, + 288, + 304 + ], + "type": "text", + "content": "[31] Karen Simonyan and Andrew Zisserman. Two-stream convolutional networks for action recognition in videos. Advances in Neural Information Processing Systems, 2014. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 305, + 288, + 347 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 305, + 288, + 347 + ], + "spans": [ + { + "bbox": [ + 48, + 305, + 288, + 347 + ], + "type": "text", + "content": "[32] Hao Tan, Jie Lei, Thomas Wolf, and Mohit Bansal. Vimpac: Video pre-training via masked token prediction and contrastive learning. arXiv preprint arXiv:2106.11250, 2021. 2, 9" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 350, + 288, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 350, + 288, + 392 + ], + "spans": [ + { + "bbox": [ + 48, + 350, + 288, + 392 + ], + "type": "text", + "content": "[33] Jing Tan, Jiaqi Tang, Limin Wang, and Gangshan Wu. Relaxed transformer decoders for direct action proposal generation. In IEEE/CVF International Conference on Computer Vision, 2021. 1" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 394, + 288, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 394, + 288, + 426 + ], + "spans": [ + { + "bbox": [ + 48, + 394, + 288, + 426 + ], + "type": "text", + "content": "[34] Zachary Teed and Jia Deng. Raft: Recurrent all-pairs field transforms for optical flow. In European conference on computer vision, pages 402-419. Springer, 2020. 2, 5, 6" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 427, + 288, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 427, + 288, + 470 + ], + "spans": [ + { + "bbox": [ + 48, + 427, + 288, + 470 + ], + "type": "text", + "content": "[35] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. Video-MAE: Masked autoencoders are data-efficient learners for self-supervised video pre-training. In Advances in Neural Information Processing Systems, 2022. 1, 2, 4, 5, 6, 7, 9" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 472, + 288, + 525 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 472, + 288, + 525 + ], + "spans": [ + { + "bbox": [ + 48, + 472, + 288, + 525 + ], + "type": "text", + "content": "[36] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Hervé Jégou. Training data-efficient image transformers & distillation through attention. In International Conference on Machine Learning, 2021. 1" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 526, + 288, + 569 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 526, + 288, + 569 + ], + "spans": [ + { + "bbox": [ + 48, + 526, + 288, + 569 + ], + "type": "text", + "content": "[37] Du Tran, Heng Wang, Matt Feiszli, and Lorenzo Torresani. Video classification with channel-separated convolutional networks. In IEEE/CVF International Conference on Computer Vision, 2019. 9" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 571, + 288, + 614 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 571, + 288, + 614 + ], + "spans": [ + { + "bbox": [ + 48, + 571, + 288, + 614 + ], + "type": "text", + "content": "[38] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Advances in Neural Information Processing Systems, 2017. 1" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 615, + 288, + 658 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 615, + 288, + 658 + ], + "spans": [ + { + "bbox": [ + 48, + 615, + 288, + 658 + ], + "type": "text", + "content": "[39] Pascal Vincent, Hugo Larochelle, Yoshua Bengio, and Pierre-Antoine Manzagol. Extracting and composing robust features with denoising autoencoders. In International Conference on Machine Learning, 2008. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 658, + 288, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 658, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 658, + 288, + 713 + ], + "type": "text", + "content": "[40] Pascal Vincent, Hugo Larochelle, Isabelle Lajoie, Yoshua Bengio, and Pierre-Antoine Manzagol. Stacked denoising autoencoders: Learning useful representations in a deep network with a local denoising criterion. Journal of Machine Learning Research, 2010. 2" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 307, + 73, + 547, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 547, + 128 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 547, + 128 + ], + "type": "text", + "content": "[41] Limin Wang, Bingkun Huang, Zhiyu Zhao, Zhan Tong, Yinan He, Yi Wang, Yali Wang, and Yu Qiao. Videomae v2: Scaling video masked autoencoders with dual masking. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14549-14560, 2023. 1, 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 129, + 547, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 129, + 547, + 184 + ], + "spans": [ + { + "bbox": [ + 307, + 129, + 547, + 184 + ], + "type": "text", + "content": "[42] Limin Wang, Yu Qiao, and Xiaou Tang. Action recognition with trajectory-pooled deep-convolutional descriptors. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2015, Boston, MA, USA, June 7-12, 2015, pages 4305-4314. IEEE Computer Society, 2015. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 186, + 547, + 229 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 186, + 547, + 229 + ], + "spans": [ + { + "bbox": [ + 307, + 186, + 547, + 229 + ], + "type": "text", + "content": "[43] Limin Wang, Zhan Tong, Bin Ji, and Gangshan Wu. TDN: Temporal difference networks for efficient action recognition. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. 3, 9" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 231, + 546, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 231, + 546, + 274 + ], + "spans": [ + { + "bbox": [ + 308, + 231, + 546, + 274 + ], + "type": "text", + "content": "[44] Limin Wang, Yuanjun Xiong, Zhe Wang, Yu Qiao, Dahua Lin, Xiaou Tang, and Luc Van Gool. Temporal segment networks for action recognition in videos. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2019. 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 276, + 547, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 276, + 547, + 330 + ], + "spans": [ + { + "bbox": [ + 308, + 276, + 547, + 330 + ], + "type": "text", + "content": "[45] Rui Wang, Dongdong Chen, Zuxuan Wu, Yinpeng Chen, Xiyang Dai, Mengchen Liu, Yu-Gang Jiang, Luowei Zhou, and Lu Yuan. Bevt: Bert pretraining of video transformers. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2, 9" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 332, + 547, + 386 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 332, + 547, + 386 + ], + "spans": [ + { + "bbox": [ + 308, + 332, + 547, + 386 + ], + "type": "text", + "content": "[46] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In IEEE/CVF International Conference on Computer Vision, 2021. 1" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 388, + 546, + 421 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 388, + 546, + 421 + ], + "spans": [ + { + "bbox": [ + 308, + 388, + 546, + 421 + ], + "type": "text", + "content": "[47] Xiaolong Wang, Ross Girshick, Abhinav Gupta, and Kaiming He. Non-local neural networks. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2018. 9" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 422, + 547, + 475 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 422, + 547, + 475 + ], + "spans": [ + { + "bbox": [ + 308, + 422, + 547, + 475 + ], + "type": "text", + "content": "[48] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2, 9" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 478, + 547, + 531 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 478, + 547, + 531 + ], + "spans": [ + { + "bbox": [ + 308, + 478, + 547, + 531 + ], + "type": "text", + "content": "[49] Enze Xie, Wenhai Wang, Zhiding Yu, Anima Anandkumar, Jose M Alvarez, and Ping Luo. Segformer: Simple and efficient design for semantic segmentation with transformers. In Advances in Neural Information Processing Systems, 2021. 1" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 534, + 547, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 534, + 547, + 588 + ], + "spans": [ + { + "bbox": [ + 308, + 534, + 547, + 588 + ], + "type": "text", + "content": "[50] Zhenda Xie, Zheng Zhang, Yue Cao, Yutong Lin, Jianmin Bao, Zhuliang Yao, Qi Dai, and Han Hu. Simmim: A simple framework for masked image modeling. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 590, + 547, + 633 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 590, + 547, + 633 + ], + "spans": [ + { + "bbox": [ + 308, + 590, + 547, + 633 + ], + "type": "text", + "content": "[51] Xitong Yang, Xiaodong Yang, Sifei Liu, Deqing Sun, Larry Davis, and Jan Kautz. Hierarchical contrastive motion learning for video action recognition. arXiv preprint arXiv:2007.10321, 2020. 3" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 635, + 547, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 635, + 547, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 635, + 547, + 689 + ], + "type": "text", + "content": "[52] Li Yuan, Yunpeng Chen, Tao Wang, Weihao Yu, Yujun Shi, Francis EH Tay, Jiashi Feng, and Shuicheng Yan. Token-to-token vit: Training vision transformers from scratch onImagenet. In IEEE/CVF International Conference on Computer Vision, 2021. 1" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 692, + 547, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 692, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 692, + 547, + 713 + ], + "type": "text", + "content": "[53] Christopher Zach, Thomas Pock, and Horst Bischof. A duality based approach for realtime tv-1 optical flow. In" + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13503" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 428 + ], + "type": "list", + "angle": 0, + "index": 7, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "type": "text", + "content": "Pattern Recognition: 29th DAGM Symposium, Heidelberg, Germany, September 12-14, 2007. Proceedings 29, pages 214-223. Springer, 2007. 5" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 288, + 138 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 288, + 138 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 288, + 138 + ], + "type": "text", + "content": "[54] Chen-Lin Zhang, Jianxin Wu, and Yin Li. Actionformer: Localizing moments of actions with transformers. CoRR, abs/2202.07925, 2022. 1" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 141, + 288, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 141, + 288, + 205 + ], + "spans": [ + { + "bbox": [ + 48, + 141, + 288, + 205 + ], + "type": "text", + "content": "[55] Guozhen Zhang, Yuhan Zhu, Haonan Wang, Youxin Chen, Gangshan Wu, and Limin Wang. Extracting motion and appearance via inter-frame attention for efficient video frame interpolation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5682-5692, 2023. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 208, + 288, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 208, + 288, + 239 + ], + "spans": [ + { + "bbox": [ + 48, + 208, + 288, + 239 + ], + "type": "text", + "content": "[56] Kaidong Zhang, Jingjing Fu, and Dong Liu. Flow-guided transformer for video inpainting. In European Conference on Computer Vision, pages 74-90. Springer, 2022. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 242, + 288, + 327 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 242, + 288, + 327 + ], + "spans": [ + { + "bbox": [ + 48, + 242, + 288, + 327 + ], + "type": "text", + "content": "[57] Yue Zhao, Yuanjun Xiong, and Dahua Lin. Trajectory convolution for action recognition. In Samy Bengio, Hanna M. Wallach, Hugo Larochelle, Kristen Grauman, Nicolò Cesà-Bianchi, and Roman Garnett, editors, Advances in Neural Information Processing Systems 31: Annual Conference on Neural Information Processing Systems 2018, NeurIPS 2018, December 3-8, 2018, Montréal, Canada, pages 2208-2219, 2018. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 331, + 288, + 384 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 331, + 288, + 384 + ], + "spans": [ + { + "bbox": [ + 48, + 331, + 288, + 384 + ], + "type": "text", + "content": "[58] Yuan Zhi, Zhan Tong, Limin Wang, and Gangshan Wu. Mgsampler: An explainable sampling strategy for video action recognition. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 1493-1502. IEEE, 2021. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 386, + 288, + 428 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 386, + 288, + 428 + ], + "spans": [ + { + "bbox": [ + 48, + 386, + 288, + 428 + ], + "type": "text", + "content": "[59] Daquan Zhou, Bingyi Kang, Xiaojie Jin, Linjie Yang, Xiaochen Lian, Qibin Hou, and Jiashi Feng. Deepvit: Towards deeper vision transformer. arXiv preprint arXiv:2103.11886, 2021. 1" + } + ] + } + ], + "index": 6 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "13504" + } + ] + } + ], + "index": 8 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 11 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/803b20b8-8ea9-4642-8b2e-1e4d0ac18614_content_list.json b/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/803b20b8-8ea9-4642-8b2e-1e4d0ac18614_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..b59923e9bbd3747f13cf563bc9c2113a2379c519 --- /dev/null +++ b/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/803b20b8-8ea9-4642-8b2e-1e4d0ac18614_content_list.json @@ -0,0 +1,1810 @@ +[ + { + "type": "text", + "text": "MHCN: A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering", + "text_level": 1, + "bbox": [ + 251, + 130, + 718, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Fangfei Lin $^{1,3*}$ , Bing Bai $^{3\\dagger}$ , Yiwen Guo $^{6\\dagger}$ , Hao Chen $^{4}$ , Yazhou Ren $^{1}$ , Zenglin Xu $^{2,5\\dagger}$ $^{1}$ University of Electronic Science and Technology of China, China $^{2}$ Peng Cheng Lab, China \n $^{3}$ Tencent Security Big Data Lab, China $^{4}$ University of California, Davis, USA \n $^{5}$ Harbin Institute of Technology Shenzhen, China $^{6}$ Independent Researcher", + "bbox": [ + 114, + 202, + 854, + 273 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{phoebe.lin1108,guoyiwen89,zenglin}@gmail.com,icebai@tencent.com", + "bbox": [ + 200, + 276, + 767, + 292 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "chen@ucdavis.edu, yazhou. ren@uestc.edu.cn", + "bbox": [ + 305, + 295, + 661, + 308 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 344, + 313, + 359 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Multi-view hierarchical clustering (MCHC) plays a pivotal role in comprehending the structures within multi-view data, which hinges on the skillful interaction between hierarchical feature learning and comprehensive representation learning across multiple views. However, existing methods often overlook this interplay due to the simple heuristic agglomerative strategies or the decoupling of multi-view representation learning and hierarchical modeling, thus leading to insufficient representation learning. To address these issues, this paper proposes a novel Multi-view Hierarchical Clustering Network (MHCN) model by performing simultaneous multi-view learning and hierarchy modeling. Specifically, to uncover efficient tree-like structures among all views, we derive multiple hyperbolic autoencoders with latent space mapped onto the Poincaré ball. Then, the corresponding hyperbolic embeddings are further regularized to achieve the multi-view representation learning principles for both view-common and view-private information, and to ensure hyperbolic uniformity with a well-balanced hierarchy for better interpretability. Extensive experiments on real-world and synthetic multi-view datasets have demonstrated that our method can achieve state-of-the-art hierarchical clustering performance, and empower the clustering results with good interpretability.", + "bbox": [ + 75, + 376, + 473, + 739 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 765, + 209, + 781 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Clustering is one of the fundamental research topics in data analysis [28, 44, 51]. With the advances in data acquisition, lots of real-world data could be presented by multiple views, e.g., different visual descriptors like GIST [48] + Histogram of Oriented Gradients (HOG) [13] + other", + "bbox": [ + 75, + 790, + 468, + 867 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/d85cef290d4514cacb305411d2d3bcca58a62eac3b33388f6c6c7f77abdff5b0.jpg", + "image_caption": [ + "Figure 1: Comparison between prior MVHC methods, i.e., MHC and CMHHC, versus our proposed MHCN. (a) MHC calculates the average cosine distance matrix of all views and agglomerates the nearest neighbors according to the simply-aligned similarity matrix. (b) CMHHC performs multi-view alignment and similarity learning in the Euclidean space, and hierarchical clustering in hyperbolic space, separately. (c) Our MHCN, a one-stage pipeline, directly aligns the latent hierarchies on different Poincaré balls, leading to more effective MVHC trees." + ], + "image_footnote": [], + "bbox": [ + 501, + 342, + 890, + 534 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "deep features [53] for an image. Multiple views contain both congruent and incongruent information, which can be leveraged to explore potential consistency and complementarity across views and provide more comprehensive latent representations to facilitate downstream tasks, especially for unsupervised learning. This leads to the prevalence of multi-view clustering including multi-view partitional clustering [29, 35, 39, 49, 59] and multi-view hierarchical clustering [37, 68]. Aiming for high interpretability, multi-view hierarchical clustering is particularly appealing in the analysis of multi-view data at various levels of gran", + "bbox": [ + 496, + 734, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*This work was done when Fangfei Lin was an intern at Tencent.", + "bbox": [ + 94, + 875, + 439, + 887 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "† Corresponding authors.", + "bbox": [ + 96, + 887, + 225, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "16525", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "ularity. For instance, gene expression analysis [36] integrates multi-omics data and clusters cells into an organization/organ/system hierarchy. Besides, species trees [17], gathering animals by their physical appearances, sounds, or other features, reflect the hierarchical organization in phylogenetic inference.", + "bbox": [ + 75, + 90, + 470, + 181 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Despite these merits, there are still significant limitations in existing multi-view hierarchical clustering methods. As shown in Figure 1, existing models for solving the MVHC problem include the discrete linkage-based method Multiview Hierarchical Clustering (MHC) [68], and the continuous deep neural network-based Contrastive Multi-view Hyperbolic Hierarchical Clustering (CMHHC) [37]. As a seminal work for MVHC, shallow MHC partitions multi-view data at multiple levels through the cosine distance integration and the nearest neighbor agglomeration components. However, without applying deep representation learning, this method simply considers the mean latent feature vectors as the common representations of all views. Thus, it cannot fully capture the consistency and complementarity among different views, leading to degenerated HC performance, especially on complicated real-world datasets. The two-stage deep model CMHHC integrates a multi-view alignment learning module, an aligned feature similarity learning module, and a continuous hyperbolic hierarchical clustering module. However, CMHHC takes into account two independent geometry settings, treating multiview learning in the Euclidean space and HC in hyperbolic space, enlarging the gap between the two processes. Thus, the performance may still be suboptimal.", + "bbox": [ + 75, + 186, + 470, + 547 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To address these issues, this paper proposes the Multi-view Hierarchical Clustering Network (MHCN), as sketched in Figure 2. Taking the desired MVHC tree structures into consideration, we make corresponding designs for MHCN as follows. Firstly, drawing inspiration from the recent success of latent hyperbolic anatomy [42, 52], which excels in modeling hierarchies with minimal distortion, we incorporate multiple hyperbolic autoencoders to capture the inherent hierarchies present in different views. Secondly, considering multi-view consistent and complementary principles [34, 66], we design the multi-view alignment loss between two arbitrary views to discover the view-common information, and use the reconstruction loss to retain the view-private information, respectively. Thirdly, uniformly-distributed hyperbolic embeddings on the Poincaré ball create well-balanced trees, leading to more interpretable semantics compared with skewed ones. In order to improve interpretability in clustering trees, we encourage the balanced hierarchy construction via a hyperbolic uniformity loss, which facilitates learning such hyperbolic embeddings. In this way, MHCN provides explicit guidance for ensuring the quality of the tree structure and integrates multi-view representation learning and hierarchy discovery", + "bbox": [ + 75, + 553, + 468, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "processes on hyperbolic manifolds with hierarchy-friendly hyperbolic autoencoders. As the pioneering one-stage solution for the MVHC problem, the MHCN model collectively optimizes the three objectives with mini-batch training. Thus, large datasets can be efficiently processed. After obtaining the optimal hyperbolic hierarchical representations for unseen data with trained neural networks, MHCN can decode back to the underlying tree structures, making inductive hierarchical clustering possible.", + "bbox": [ + 496, + 90, + 890, + 226 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Different from existing MVHC models, our contributions are summarized as follows.", + "bbox": [ + 498, + 227, + 890, + 256 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We analyze the multi-view hierarchical clustering problem and propose a novel hyperbolic neural network-based model to tackle the problem, where the latent space is grafted on the Poincaré ball of hyperbolic space for explicit hierarchical structures.", + "- We introduce three objectives to facilitate the final multi-view hierarchical clustering trees with desired properties, i.e., a multi-view alignment loss, a reconstruction loss, and a hyperbolic uniformity loss.", + "- We conduct extensive experiments to show the superiority of MHCN compared with other multi-view HC methods in terms of both effectiveness and scalability." + ], + "bbox": [ + 517, + 262, + 890, + 458 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 474, + 640, + 489 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Hierarchical Clustering", + "text_level": 1, + "bbox": [ + 500, + 500, + 718, + 515 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Bottom-up linkage algorithms for solving HC are simple and easy to implement, which recursively merge similar data points to build larger cluster sub-trees until a complete dendrogram appears [10, 31]. Typical agglomerative heuristics include Single Linkage, Complete Linkage, Average Linkage, and Ward Linkage [10]. While these traditional algorithms are widely used in practice, there is a limit to fit continuous optimization due to their inherent discreteness [14, 43, 61]. Hence, there have been more attempts at gradient-based HC through embedding methods recently [5, 9, 24, 46, 56]. For example, UFit [9] proposed a gradient-based fitting framework over ultrametric. Besides, similarity-based HypHC [5] directly relaxed Dasgupta's cost with the aid of the continuous form of hyperbolic leaf nodes and lowest common ancestors (LCAs).", + "bbox": [ + 496, + 523, + 890, + 748 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In contrast to the above HC methods, our unified framework is multi-view data-oriented, which can be optimized continuously via specifically-designed hierarchical clustering objectives. Also, little previous research pays close attention to the balancing property of clustering trees, which is one of the mainly-addressed spots in our method.", + "bbox": [ + 496, + 750, + 890, + 839 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. Multi-view Clustering", + "text_level": 1, + "bbox": [ + 500, + 847, + 705, + 863 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Existing multi-view clustering (MVC) methods can be roughly classified into four categories, namely, canon-", + "bbox": [ + 500, + 869, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "16526", + "bbox": [ + 480, + 945, + 519, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/2c883b2229c78c6a7083be34be73dea6f6ee16d84c01a9ef262cc3556f8719b8.jpg", + "image_caption": [ + "Figure 2: Overview of the proposed MHCN (taking two views as an example). MHCN assigns a hyperbolic autoencoder to each view, with the latent space grafted on the Poincaré ball for explicit hierarchies, where the exponential mapping function $\\exp_0$ follows the hyperbolic encoder, and the hyperbolic decoder connects behind the logarithm mapping function $\\log_0$ . The whole model is trained with the three joint learning objectives: (1) the multi-view alignment learning aims to align the hyperbolic embeddings $z_i^1$ and $z_i^2$ , (2) the reconstruction for HAE is used to project the complementary information in each view into the latent space, and (3) the hyperbolic uniformity learning guarantees $z_i^1$ and $z_i^2$ to distribute uniformly on the corresponding Poincaré balls, respectively. After $\\beta$ -fusion, the final MVHC tree can be decoded from the common hyperbolic representations." + ], + "image_footnote": [], + "bbox": [ + 158, + 88, + 816, + 354 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "ical correlation analysis-based [8], matrix factorization-based [3], subspace-based [27, 33] and graph-based [30] methods. Recently, deep MVC methods have been developed increasingly [35, 38, 49, 53, 59, 67]. However, most methods are limited to partitional clustering. The high computational complexities of these methods hinder the practicability and development of multi-view hierarchical clustering. To this end, research about MVHC has gradually emerged. Shallow MHC [68] roughly averages the cosine distance graphs for common latent features, which cannot achieve consistency of all views. A recent two-stage deep method CMHHC [37] presents an MVHC tree over aligned common representations through three modules, i.e., multiview alignment learning, unsupervised metric learning, and hyperbolic hierarchical clustering.", + "bbox": [ + 75, + 513, + 468, + 739 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Unlike CMHHC, which regards multi-view representation learning and hierarchical clustering as two separate stages, our method unifies them into a one-stage training pipeline, where they can reinforce each other for naturally contributing to the final HC trees.", + "bbox": [ + 75, + 741, + 468, + 816 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.3. Hyperbolic Models", + "text_level": 1, + "bbox": [ + 76, + 830, + 261, + 847 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "There is extensive literature on hierarchical models conducted in the Euclidean space and its applications [22, 25, 58]. However, suffering from the inherent discrete na", + "bbox": [ + 76, + 854, + 468, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "ture of trees, the Euclidean hierarchical models have difficulty in constructing the hierarchical structure of data explicitly, while hyperbolic models can. The underlying reason is that the exponential growth of the volume in hyperbolic space with its radius is analogous to the exponential growth of the number of leaves in a tree with its altitude, which is infeasible in the Euclidean space [43]. Thus, there has been an increasing interest in the generalization of hyperbolic neural networks to learn hyperbolic representations [6, 20, 26, 42, 50, 55].", + "bbox": [ + 496, + 513, + 890, + 666 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Method", + "text_level": 1, + "bbox": [ + 500, + 678, + 589, + 694 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this part, we propose a hyperbolic neural network model for MVHC, termed as Multi-view Hierarchical Clustering Network (MHCN), as shown in Figure 2. For clarity, we first briefly review the background of hyperbolic geometry and a specific hyperbolic model, i.e., the Poincaré ball. Then, we describe the architecture of HAE, define what desired trees look like through specific loss functions, and introduce the decoding strategy. Lastly, we summarize the whole optimization process.", + "bbox": [ + 496, + 704, + 890, + 839 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Let $\\{\\pmb{X}^m\\in \\mathbb{R}^{N\\times D_m}\\}_{m = 1}^M$ be a multi-view dataset including $N$ samples across $M$ views, where each $\\pmb{x}_i^m\\in \\mathbb{R}^{D_m}$ denotes the $i$ -th instance of $D_{m}$ dimension from the $m$ -th view. Our target is to present a unified method for", + "bbox": [ + 496, + 839, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "16527", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "clustering tree learning by searching over multi-view continuous hierarchical representations in hyperbolic space.", + "bbox": [ + 76, + 90, + 468, + 122 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.1. Preliminaries", + "text_level": 1, + "bbox": [ + 76, + 133, + 217, + 148 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We first introduce the Riemannian geometry and the Poincaré ball model of hyperbolic geometry, with which we build the hyperbolic autoencoders for our model. A more detailed review can be found in the appendix.", + "bbox": [ + 76, + 159, + 468, + 220 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.1.1 Riemannian Geometry", + "text_level": 1, + "bbox": [ + 76, + 244, + 290, + 262 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "An $n$ -dimensional manifold $\\mathcal{M}$ [19, 54] is a real and smooth space, which can be locally approximated to a linear $n$ -dimensional space $\\mathbb{R}^n$ at each point $\\pmb{x} \\in \\mathcal{M}$ . For any point $\\pmb{x}$ of the manifold $\\mathcal{M}$ , the corresponding local tangent space $\\mathcal{T}_x\\mathcal{M}$ , is the first order linear approximation of $\\mathcal{M}$ around the point $\\pmb{x}$ . The related metric tensor $g_x: \\mathcal{T}_x\\mathcal{M} \\times \\mathcal{T}_x\\mathcal{M} \\to \\mathbb{R}$ defines an inner product on $\\mathcal{T}_x\\mathcal{M}$ and a Riemannian metric $g = (g_x)_{x \\in \\mathcal{M}}$ is a set of such inner products on $\\mathcal{M}$ . In this way, a Riemannian manifold can be presented as a matching tuple $(\\mathcal{M}, g)$ . With $g_x$ , the local geometric attributions of $\\mathcal{T}_x\\mathcal{M}$ are accessible, and then the global distances can be achieved by integrating the local properties together. To project a tangent vector $z$ in $\\mathcal{T}_x\\mathcal{M}$ onto $\\mathcal{M}$ along a geodesic with constant velocity, the exponential map $\\exp_x: \\mathcal{T}_x\\mathcal{M} \\to \\mathcal{M}$ is given, and the inverse form is logarithmic map $\\log_x: \\mathcal{M} \\to \\mathcal{T}_x\\mathcal{M}$ [20, 52, 55]. More detailed review is in the appendix.", + "bbox": [ + 76, + 271, + 472, + 530 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.1.2 Poincaré Ball Model of Hyperbolic Geometry", + "text_level": 1, + "bbox": [ + 76, + 554, + 446, + 569 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Many studies [12, 21, 47] have demonstrated that data representations in most machine learning applications lie on a Riemannian manifold [32]. Later on, how to generalize neural networks to a Riemannian space has made remarkable progress [15, 42, 45]. An $n$ -dimensional hyperbolic space $\\mathbb{H}^n$ is an $n$ -dimensional Riemannian manifold with constant negative curvature [2, 4]. We choose to perform our model on the $n$ -dimensional Poincaré ball $(\\mathbb{B}^n,g^{\\mathbb{B}})$ with a constant negative curvature $-1$ , where $\\mathbb{B}^n = \\{\\pmb {x}\\in \\mathbb{R}^n:||\\pmb {x}||^2 < 1\\}$ is an open ball of curvature $-1$ , and its hyperbolic metric tensor $g_{\\pmb{x}}^{\\mathbb{B}} = \\lambda_{\\pmb{x}}^{2}g^{E}$ is conformal to the Euclidean one. $\\lambda_{\\pmb{x}}^{2} = \\frac{2}{1 - ||\\pmb{x}||^{2}}$ is a conformal factor, and $g^{E} = I_{n}$ denotes the dot product in the Euclidean space.", + "bbox": [ + 76, + 580, + 468, + 777 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Given $z, z' \\in \\mathbb{B}^n$ and $t \\in \\mathcal{T}_z\\mathbb{B}^n$ , the exponential map $\\exp_z: \\mathcal{T}_z\\mathbb{B}^n \\to \\mathbb{B}^n$ and the logarithm map $\\log_z: \\mathbb{B}^n \\to \\mathcal{T}_z\\mathbb{B}^n$ realize the projection from the Euclidean space onto the Poincaré ball and vice versa, respectively. To enable the mathematical operations for hyperbolic space models, the framework of gyrovector spaces provides the algebraic setting for the hyperbolic geometry. With the Möbius Addition $\\oplus$ [60], the closed-form expressions of", + "bbox": [ + 76, + 779, + 470, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "$\\exp_z$ and $\\log_z$ are respectively given by", + "bbox": [ + 500, + 90, + 767, + 107 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\exp_ {z} (\\boldsymbol {t}) = \\boldsymbol {z} \\oplus \\left(\\tanh \\left(\\frac {\\lambda_ {z} \\| \\boldsymbol {t} \\|}{2}\\right) \\frac {\\boldsymbol {t}}{\\| \\boldsymbol {t} \\|}\\right), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 514, + 114, + 890, + 155 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\log_ {z} (z ^ {\\prime}) = \\frac {2}{\\lambda_ {z}} \\mathrm {a r c t a n h} (| | - z \\oplus z ^ {\\prime} | |) \\frac {- z \\oplus z ^ {\\prime}}{| | - z \\oplus z ^ {\\prime} | |}.\n$$\n", + "text_format": "latex", + "bbox": [ + 514, + 150, + 859, + 181 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "For the convenience in practice, $z$ is usually set to the origin $\\mathbf{0}$ , so the $\\exp_z$ and $\\log_z$ can be simplified as", + "bbox": [ + 500, + 190, + 890, + 220 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\exp_ {\\mathbf {0}} (\\boldsymbol {t}) = \\tanh (| | \\boldsymbol {t} | |) \\frac {\\boldsymbol {t}}{| | \\boldsymbol {t} | |}), \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 584, + 227, + 890, + 268 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\log_ {\\mathbf {0}} \\left(\\boldsymbol {z} ^ {\\prime}\\right) = \\operatorname {a r c t a n h} \\left(\\left| \\left| \\boldsymbol {z} ^ {\\prime} \\right| \\right|\\right) \\frac {\\boldsymbol {z} ^ {\\prime}}{\\left| \\left| \\boldsymbol {z} ^ {\\prime} \\right| \\right|}.\n$$\n", + "text_format": "latex", + "bbox": [ + 584, + 262, + 807, + 294 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "By means of the above main operations $\\exp_0(t)$ and $\\log_0(z')$ , MHCN is able to perform the basic transformations of the latent representations between the Euclidean space and the hyperbolic space.", + "bbox": [ + 498, + 301, + 890, + 364 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Hyperbolic Autoencoders", + "text_level": 1, + "bbox": [ + 500, + 371, + 732, + 387 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The conventional approach to learning useful representations is through a regular Euclidean autoencoder [18, 23, 64]. However, there has been significant interest in hierarchical representation learning using non-Euclidean geometry, specifically the hyperbolic space. This attention arises from the fact that the number of leaf nodes in tree structures increases exponentially with depth, mirroring the exponential growth of the hyperbolic surface area with its radius, while the growth in the Euclidean space is polynomial [6, 20, 52, 55]. As a result, we augment the standard autoencoder with hyperbolic geometry in the embedding space, and propose a novel multi-view hyperbolic model consisting of multiple hyperbolic autoencoders assigned for different views, shown in Figure 2. Each hyperbolic autoencoder's geometry-aware encoder and decoder are constructed via the introduced exponential and logarithmic map functions in Eq.(2). We show the detailed structures of the encoders and the decoders in the following.", + "bbox": [ + 496, + 393, + 890, + 667 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2.1 Encoder with the Exponential Map", + "text_level": 1, + "bbox": [ + 500, + 684, + 799, + 700 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "With regard to the $m$ -th view $\\pmb{X}^{m}$ , the encoder of $m$ -th HAE, i.e., $f_{\\mathrm{enc}}(\\pmb{X}^{m};\\theta_{\\mathrm{enc}}^{m}): \\pmb{X}^{m} \\in \\mathbb{R}^{D_{m}} \\to \\pmb{Z}_{\\mathrm{hyp}}^{m} \\in \\mathbb{B}^{d}$ , is designed as a regular Euclidean encoder followed by the exponential map $\\exp_0(\\cdot)$ , along with which the output of the hyperbolic encoder is projected onto the Poincaré ball. $\\pmb{Z}_{\\mathrm{hyp}}^{m}$ represents the $d$ -dimensional hyperbolic latent code with explicit hierarchical patterns and $\\theta_{\\mathrm{enc}}^{m}$ denotes the encoder parameters.", + "bbox": [ + 498, + 707, + 890, + 829 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2.2 Decoder with the Logarithm Map", + "text_level": 1, + "bbox": [ + 500, + 845, + 789, + 862 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Similar to the hyperbolic encoder, the decoder of the $m$ -th HAE, $f_{\\mathrm{dec}}(\\pmb{X}^m;\\theta_{\\mathrm{dec}}^m): \\pmb{Z}_{\\mathrm{hyp}}^m \\in \\mathbb{B}^d \\to \\pmb{X}^m \\in \\mathbb{R}^{D_m}$", + "bbox": [ + 498, + 869, + 890, + 902 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "16528", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "for the $m$ -th view $\\mathbf{X}^m$ which is parameterized by $\\theta_{\\mathrm{dec}}^m$ , is constituted of a regular Euclidean decoder preprocessed by the logarithm map $\\log_0(\\cdot)$ , projecting the latent hyperbolic features back to the Euclidean space.", + "bbox": [ + 75, + 90, + 468, + 151 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.3. Loss Functions for Desired HC Trees", + "text_level": 1, + "bbox": [ + 76, + 160, + 395, + 175 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "High-quality MVHC trees should: 1) preserve the intrinsic hierarchy of each view via learned hyperbolic embeddings, 2) make full use of multi-view complementary and consistent information to acquire common hierarchical representations, and 3) not increase hierarchies without strong necessity [1, 7, 14, 62]. In this section, based on the structure of multi-view HAEs, we design the total loss functions for our model to realize the above characteristics:", + "bbox": [ + 75, + 183, + 468, + 303 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\mathrm {m v l}} + \\mathcal {L} _ {\\mathrm {u n i}}. \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 194, + 316, + 468, + 332 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In our model, we jointly achieve the multi-view consistency and complementarity in the hyperbolic common-view space by optimizing the combined loss $\\mathcal{L}_{\\mathrm{mvl}}$ of the multi-view alignment loss $\\mathcal{L}_{\\mathrm{align}}$ and the reconstruction loss $\\mathcal{L}_{\\mathrm{rc}}$ :", + "bbox": [ + 75, + 344, + 468, + 405 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {m v l}} = \\alpha \\mathcal {L} _ {\\text {a l i g n}} + (1 - \\alpha) \\mathcal {L} _ {\\mathrm {r c}}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 166, + 417, + 468, + 431 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\alpha$ is a trade-off coefficient to balance the effects of consistency and complementarity for multi-view learning.", + "bbox": [ + 75, + 444, + 468, + 473 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Learning view-common consistency with the multi-view alignment loss. The extracted common representations $\\{Z_{\\mathrm{hyp}}^m = f_{\\mathrm{enc}}(X^m)\\}_{m=1}^M$ are expected not only to uncover the complementary relationships among different views but also to contain sufficient consensus information of all views. To achieve consistency across multiple views, we apply distance and similarity-based alignment by conducting a multi-view alignment loss endowed on the hyperbolic embeddings. Here, we consider the cosine distance between two latent features $z_i^{m_1}$ and $z_j^{m_2}$ as the similarity measurement for multi-view alignment:", + "bbox": [ + 75, + 474, + 468, + 640 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\sin \\left(\\boldsymbol {z} _ {i} ^ {m _ {1}}, \\boldsymbol {z} _ {i} ^ {m _ {2}}\\right) = \\frac {\\left\\langle \\boldsymbol {z} _ {i} ^ {m _ {1}} , \\boldsymbol {z} _ {j} ^ {m _ {2}} \\right\\rangle}{\\left| \\left| \\boldsymbol {z} _ {i} ^ {m _ {1}} \\right| \\right| \\left| \\left| \\boldsymbol {z} _ {j} ^ {m _ {2}} \\right| \\right|}. \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 155, + 650, + 468, + 686 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Supported by the conformality property of the Riemannian geometry, i.e., the Poincaré ball preserves the same angels as the Euclidean space, the computation of the cosine similarity in the Euclidean space is equal to that on the Poincaré ball [20, 55]. Besides, unlike the geodesic distances, values of the cosine distances are kept in a certain range, which is friendly to optimization processes.", + "bbox": [ + 75, + 696, + 468, + 801 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Then, the multi-view alignment loss between the hyperbolic embeddings of the same instance from any two views $Z_{\\mathrm{hyp}}^{m_1}, Z_{\\mathrm{hyp}}^{m_2}$ is given by:", + "bbox": [ + 76, + 803, + 468, + 851 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {a l i g n}} ^ {(m _ {1}, m _ {2})} = - \\frac {1}{N} \\sum_ {i = 1} ^ {N} \\sin \\left(\\boldsymbol {z} _ {i} ^ {m _ {1}}, \\boldsymbol {z} _ {i} ^ {m _ {2}}\\right) / \\tau_ {\\text {a l i g n}}, \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 120, + 862, + 468, + 902 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\tau_{\\mathrm{align}}$ is used as a temperature parameter for the scaled distance function. Here, we notice that CMHHC [37] also serves to learn common representations. However, CMHHC aligns Euclidean features, while MHCN directly makes the corresponding hyperbolic embeddings closer.", + "bbox": [ + 496, + 90, + 890, + 166 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Therefore, the complete multi-view alignment loss across all view pairs is formulated as:", + "bbox": [ + 496, + 167, + 890, + 196 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {a l i g n}} = \\sum_ {m _ {1} = 1} ^ {M} \\sum_ {m _ {2} = 1, m _ {1} \\neq m _ {2}} ^ {M} \\mathcal {L} _ {\\text {a l i g n}} ^ {(m _ {1}, m _ {2})}. \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 565, + 204, + 890, + 246 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Learning view-private complementarity with the reconstruction loss of HAEs. In multi-view representation learning models, autoencoders are widely used for their impressive strengths, such as preserving the useful view-private information and preventing data points from collapsing to a small number of clusters [29, 67]. In our multi-view hierarchical clustering model, the learned representations by multiple HAEs consider the preservation of the local hierarchical structure within each view. This implies that similar instances from each view remain close to each other in the hyperbolic space, while the latent codes obtained from dissimilar instances remain distant from one another. To this end, the total reconstruction loss function of HAEs for multiple views is formulated as", + "bbox": [ + 496, + 253, + 890, + 464 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {r c}} = \\sum_ {m = 1} ^ {M} \\mathcal {L} _ {\\mathrm {r c}} ^ {m} = \\sum_ {m = 1} ^ {M} \\frac {1}{N} \\sum_ {i = 1} ^ {N} \\left| \\left| \\boldsymbol {x} _ {i} ^ {m} - f _ {\\mathrm {d e c}} \\left(f _ {\\mathrm {e n c}} \\left(\\boldsymbol {x} _ {i} ^ {m}\\right)\\right) \\right| \\right| _ {2} ^ {2}, \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 501, + 472, + 890, + 526 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathcal{L}_{\\mathrm{rc}}^m$ is the corresponding $m$ -th view objective to reconstruct $\\pmb{X}^{m}$ .", + "bbox": [ + 496, + 527, + 890, + 554 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Learning tree balancing property with the hyperbolic uniformity loss. Through the multi-view alignment and reconstruction related to the Poincaré ball, our model obtains reliable multi-view representations and discovers the hierarchical structure of each view simultaneously. Last but not least, a hierarchical clustering tree with explicit balancing property provides fewer hierarchies and higher interpretability than skewed ones.", + "bbox": [ + 496, + 556, + 890, + 676 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Consequently, we leverage the uniformity of the hyperbolic embedding distribution located on the Poincaré ball to learn separable features and enhance the contribution of the balanced affinity. Concretely, considering the form of Gaussian potential kernel [11, 40], we define a hyperbolic uniformity objective based on the cosine distance as:", + "bbox": [ + 496, + 678, + 890, + 767 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {u n i}} = \\sum_ {m = 1} ^ {M} \\frac {1}{N ^ {2}} \\sum_ {i = 1} ^ {N} \\sum_ {j = 1} ^ {N} \\log \\left(e ^ {- t \\left(- \\operatorname {s i m} \\left(\\boldsymbol {z} _ {i} ^ {m}, \\boldsymbol {z} _ {j} ^ {m}\\right) / \\tau_ {\\mathrm {u n i}}\\right)}\\right). \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 508, + 775, + 890, + 816 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Still, the temperature parameter $\\tau_{\\mathrm{uni}}$ is a scaling factor to the cosine distance. Intuitively, the hyperbolic uniformity loss encourages the latent hyperbolic embeddings to push farther away from each other and to benefit the uniform global distribution of embeddings on the Poincaré ball.", + "bbox": [ + 496, + 825, + 890, + 898 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "16529", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.4. From Hyperbolic Embeddings to Binary Trees", + "text_level": 1, + "bbox": [ + 76, + 90, + 467, + 107 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We first adopt $\\beta$ -fusion [55] to concatenate the optimal hyperbolic embeddings from multiple views into the common-view space, to guarantee the concatenated norms maintain upper-bounded by the radius of the Poincaré ball. To output an intuitive HC tree from the common continuous hyperbolic representations on the Poincaré ball back to discrete HC trees with low error, we apply the decoding strategy proposed by [5], which realizes the underlying correspondence between the hyperbolic embeddings and the HC trees with low-error. This bottom-up decoding algorithm decodes the common hyperbolic embeddings by measuring the similarity of any two embeddings with the distance from their lowest common ancient (LCA) to the origin of the ball and merging more similar ones iteratively.", + "bbox": [ + 75, + 113, + 468, + 325 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "3.5. Optimization Process", + "text_level": 1, + "bbox": [ + 76, + 335, + 276, + 351 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The whole optimization process of MHCN is summarized in the appendix. We train this model by adopting a one-stage pipeline of mini-batch gradient descent, making our method feasible to scale up to large-scale scenarios. Concretely, the integrated framework of multiple HAEs is optimized collectively with the $\\mathcal{L}_{\\mathrm{total}}$ in Eq.(3).", + "bbox": [ + 75, + 359, + 467, + 450 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 464, + 207, + 479 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In the following, we conduct experiments to verify the effectiveness and efficiency of the proposed method and analyze the results.", + "bbox": [ + 76, + 489, + 467, + 532 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Experimental Settings", + "text_level": 1, + "bbox": [ + 76, + 544, + 282, + 560 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Datasets. Following literature [37, 53, 57, 59, 63, 67], we adopt seven common multi-view datasets in our experiments, including five regular-scale datasets (MNIST-USPS, BDGP, Caltech, COIL-20 and BBCSport) and two largescale datasets (Multi-Fashion and NR-MNIST). MNIST-USPS [53] is a handwritten digital dataset with 5,000 images from 10 categories, where the digits from MNIST and USPS are two views. BDGP [35] includes 2,500 images of Drosophila embryos divided into 5 classes, characterized by visual and textual features. Caltech [16] containing 1,400 RGB images of 7 classes is constructed with 5 different visual descriptors. COIL-20 [59] contains 480 grayscale images of 20 classes, described by 3 different angles. BBCSport [41] is a text dataset in 5 topic areas. It consists of 544 documents collected from the BBC Sport website of sports news articles, related to 2 different viewpoints. Multi-Fashion [66] is also a grayscale image dataset on 10 kinds of 10,000 fashionable products. Three different views are represented by three products from the same category. In terms of NR-MNIST [65], we regard the noise-processed MNIST and the rotated-processed MNIST as two views. We use 60,000 image pairs for the general MVHC", + "bbox": [ + 75, + 568, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "experiments in Section 4.2, and use the rest 10,000 image pairs for the inductive HC experiments in Section 4.5.", + "bbox": [ + 500, + 90, + 888, + 119 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Dendrogram Purity measurement for HC. The tree structures with various fine-grained partitional clusters can be truncated at any level. Therefore, instead of using partitional clustering metrics, e.g., ACC and NMI, evaluating the performance of a clustering tree needs a much more comprehensive measurement. To this end, we adopt the Dendrogram Purity (DP) measurement to evaluate the quality of the clustering tree [31, 37, 43], which computes the average purity over the descendant leaves of LCA of all data point pairs belonging to the same ground-truth clusters. Trees with higher DP results tend to be more similar to the ground-truth clusters. Note that the Dasgupta's Cost, another HC metric applied in [5], requires an uncontroversial predefined similarity measurement as input, which is not available in our settings. The detailed reasons for using DP and not using ACC or NMI are given in the appendix.", + "bbox": [ + 496, + 122, + 890, + 364 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Baseline methods. The baselines include three kinds of methods as follows: (1) shallow discrete single-view hierarchical agglomerative clustering methods (HACs), e.g., Single-linkage, Complete-linkage, Average-linkage, and Ward-linkage algorithms; (2) deep continuous single-view HC approaches, e.g., UFit and HypHC, where we concatenate the raw features of all views into a single-view pattern [53]; and (3) State-of-the-art MVHC methods, including MHC and CMHHC.", + "bbox": [ + 496, + 364, + 890, + 500 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Implementation. The proposed network architecture is trained with the PyTorch platform. The fully connected networks with the same architecture are adopted to implement the HAEs for all views in our MHCN. We use the minimal dataset-dependent hyperparameter set for tuning. Since the parameters in hyperbolic space can be considered as Euclidean parameters computed through $Z_{\\mathrm{hyp}}^{m} = \\exp_{0}(Z_{\\mathrm{tan}}^{m})$ , where $Z_{\\mathrm{tan}}^{m} \\in \\mathbb{R}^{d}$ , we directly train our model by using the common optimizer Adam. All experiments are conducted on a Linux Server with an Intel Xeon E5-2630 v4 CPU, an NVIDIA TITAN Xp GPU, and 128GB RAM. More implementation details are provided in the supplementary materials.", + "bbox": [ + 496, + 500, + 890, + 696 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Experimental Results and Analysis", + "text_level": 1, + "bbox": [ + 500, + 710, + 803, + 726 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The comparison results are shown in Table 1. DP results of the baseline methods on all datasets except NR-MNSIT are directly taken from [37]. We can observe that: (1) MHCN outperforms the second-best baseline, i.e., CMHHC, on all datasets. Unlike two-stage CMHHC, our one-stage framework relieves the separation of multi-view representation learning and hierarchical clustering and naturally makes two associated processes boost each other. (2) Compared with the representative shallow MHC, our deep model also obtains considerable improvements on all datasets. MHC is not capable of learning rich multi-view", + "bbox": [ + 496, + 734, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "16530", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/0d0bcd8dfb93667aedf672831f87798838c4156cca528a0d83dbae0244e08ba1.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodMNIST-USPSBDGPCaltechCOIL-20BBCSportMulti-FashionNR-MNIST
HAC-Single29.81%61.88%23.67%72.56%27.66%27.89%25.77%
HAC-Complete54.36%56.57%30.19%69.95%34.78%48.72%27.71%
HAC-Average69.67%45.91%30.90%73.14%29.05%65.70%59.74%
HAC-Ward80.38%58.61%35.69%80.81%62.65%72.33%76.91%
UFit21.67%69.20%19.00%55.41%30.33%25.94%OOM
HyperHC32.99%31.21%22.46%28.50%29.08%25.65%OOM
MHC78.27%89.14%45.22%66.50%42.43%54.81%40.87%
CMHHC94.49%91.53%66.52%84.89%53.50%96.25%OOM
MHCN99.22%96.22%77.14%94.70%78.93%97.67%98.71%
", + "bbox": [ + 91, + 88, + 880, + 270 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/5a961c0052161224ca2b66696752342adc8a918235b499c780117ca1864653ac.jpg", + "table_caption": [ + "Table 1: Comparison results. Higher DP values indicate better clustering performance. \"OOM\" is out-of-memory on our server." + ], + "table_footnote": [], + "table_body": "
VariantsMNIST-USPSBDGPCaltechCOIL-20BBCSportMulti-FashionNR-MNIST
MHCN (complete)99.22%96.22%77.14%94.70%78.93%97.67%98.71%
w/o Lrc99.07%95.46%*75.17%†93.85%78.38%96.78%*98.20%
w/o Lalign41.29%†56.83%†57.56%†78.68%†40.58%†53.16%†28.36%†
w/o Luni19.42%†44.31%†36.69%†51.57%†28.52%†40.37%†32.64%†
Euclidean AEs92.72%†52.47%†32.50%†70.69%†56.58%†60.55%†53.30%†
", + "bbox": [ + 78, + 323, + 895, + 440 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 2: Ablation study of our method. “*” and “†” indicate that the difference is significant at 0.05 and 0.01, respectively.", + "bbox": [ + 81, + 448, + 883, + 465 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/9de1e42d495922a07a145a1bc5acc790a597ef9e5dcfde08944732ba83e07a6c.jpg", + "image_caption": [ + "(a) Without $\\mathcal{L}_{\\mathrm{uni}}$" + ], + "image_footnote": [], + "bbox": [ + 119, + 477, + 362, + 555 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/2fabbc73164c0d5e7916e0a295df27126b751d119ffa43827afa14e8c87b85f1.jpg", + "image_caption": [ + "(b) With $0.1^{*}\\mathcal{L}_{\\mathrm{uni}}$", + "Figure 3: Illustrations of the effectiveness of hyperbolic uniformity learning. We visualize the hyperbolic embeddings and the top-35 non-leaf internal nodes of corresponding decoding dendrograms. Left: Distributions of the learned hyperbolic embeddings optimized by different weights of $\\mathcal{L}_{\\mathrm{uni}}$ , i.e., 0.0, 0.1, and 1.0. Right: Top-35 non-leaf internal nodes of corresponding decoding dendrograms. With the weight of $\\mathcal{L}_{\\mathrm{uni}}$ increasing, the distribution becomes uniform and the dendrograms are gradually balanced." + ], + "image_footnote": [], + "bbox": [ + 364, + 478, + 606, + 554 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/0b77a8ddc5e55d3021a913016d9bfe2ec6f19276cbf84e1bc2d7b38036d463d3.jpg", + "image_caption": [ + "(c) With $\\mathcal{L}_{\\mathrm{uni}}$" + ], + "image_footnote": [], + "bbox": [ + 609, + 478, + 852, + 554 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "hierarchical representations as a result of poor hierarchical representation ability and ignorance of the balancing property of the tree structure. (3) Our method performs significantly better than all multi-view concatenation followed by single-view discrete or continuous HC methods. In contrast to concatenating features of all views simply, through learning the multi-view alignment and preserving each view's local relationships, MHCN encodes the meaningful common hierarchical representations across multiple views into the latent hyperbolic space. (4) The performance of MHCN on large-scale NR-MNIST is much better than other comparison methods. Meanwhile, conducting deep methods, like UFit, HyperHC, and CMHHC, on oversized NR-MNSIT re", + "bbox": [ + 75, + 693, + 472, + 891 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "sults in high time complexity and unbearable memory cost. The scalability of MHCN can be attributed to the one-stage pipeline to optimize the total loss by batch-based training.", + "bbox": [ + 498, + 693, + 890, + 739 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Ablation Studies", + "text_level": 1, + "bbox": [ + 500, + 753, + 665, + 768 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "To further understand the effectiveness of all the factors of MHCN, we conduct ablation studies and report the results in Table 2. We mainly consider the following ablations, i.e., (a) MHCN without $\\mathcal{L}_{\\mathrm{rc}}$ , (b) MHCN without $\\mathcal{L}_{\\mathrm{align}}$ , (c) MHCN without $\\mathcal{L}_{\\mathrm{uni}}$ , and (d) MHCN with Euclidean autoencoders. We also report the significance of test results for the differences compared with MHCN.", + "bbox": [ + 496, + 777, + 890, + 883 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "As shown in Table 2, $\\mathcal{L}_{\\mathrm{align}}$ and $\\mathcal{L}_{\\mathrm{uni}}$ both contribute", + "bbox": [ + 517, + 885, + 890, + 901 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "16531", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/829c5a0e96a11adcef07f36f2c15e51d0393a59570748cbec5c1710eaac13f2d.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Running TimeMHCNHAC-SingleHAC-CompleteHAC-AverageHAC-Ward
NR-MNIST900.92s1823.43s1903.12s2055.16s2204.11s
", + "bbox": [ + 163, + 88, + 803, + 133 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 3: Total time spent of MHCN and HACs on NR-MNIST dataset.", + "bbox": [ + 250, + 145, + 718, + 160 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/015c2a6544b227a6320fdffb513628017b043051a68ede74ad2df42045831a56.jpg", + "image_caption": [ + "Figure 4: The sampled sub-tree of LCA #19978 from the Multi-Fashion HC tree. We can observe that the sub-trees containing more similar kinds of products are closer, e.g., categories Shirt in the green circle and T-Shirt/Top in the blue circle, while less similar products are merged together at higher LCA, e.g., categories Shirt in the green circle and Trouser in the purple circle, or categories Bag in the orange circle and Trouser in the purple circle." + ], + "image_footnote": [], + "bbox": [ + 106, + 176, + 867, + 425 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "a lot to the final performance. The effectiveness of $\\mathcal{L}_{\\mathrm{rc}}$ is relatively less significant. This may be due to the property of experimental datasets. Especially, such datasets e.g., MNIST-USPS, Multi-Fashion, and NR-MNSIT are constructed by picking pairs of individual objects from the corresponding classes of multiple datasets [53, 65, 67]. So consistency may play a much more important role compared with complementarity. As for MHCN with Euclidean AEs, we can find that the performance also degenerates significantly, indicating the effectiveness of hyperbolic embeddings for modeling hierarchies.", + "bbox": [ + 75, + 523, + 472, + 691 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In addition, to intuitively show the effectiveness of $\\mathcal{L}_{\\mathrm{uni}}$ , taking MNIST-USPS as an example, we train an MHCN model mapping the data to a two-dimensional Poincaré ball with different weights for $\\mathcal{L}_{\\mathrm{uni}}$ . We visualize the averaged embeddings and the decoded clustering trees. For clarity, we present the top-35 non-leaf nodes in Figure 3. As shown, if $\\mathcal{L}_{\\mathrm{uni}}$ is absent, only $\\mathcal{L}_{\\mathrm{align}}$ for multi-view consistency and $\\mathcal{L}_{\\mathrm{rc}}$ for multi-view complementarity will force the embeddings to gather in a small corner of the Poincaré ball, resulting in a skewed tree that lacks interpretability. With the weight of $\\mathcal{L}_{\\mathrm{uni}}$ growing, the embeddings become more uniformly distributed, and the corresponding clustering trees become more balanced.", + "bbox": [ + 75, + 703, + 468, + 898 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.4. Scalability Analysis", + "text_level": 1, + "bbox": [ + 500, + 523, + 686, + 540 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "As shown in Table 1, the DP results of our method exceed those of other baselines on the large-scale NR-MNIST dataset. Also, Table 3 shows that the running time of our method achieves a significant decline when compared with the classic baselines, i.e., HACs. The theoretical complexity analysis can be found in the appendix.", + "bbox": [ + 496, + 547, + 890, + 638 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.5. Inductive Hierarchical Clustering Experiments", + "text_level": 1, + "bbox": [ + 498, + 647, + 890, + 665 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "It is difficult for traditional HAC-based methods to train on one dataset and then predict on another. However, this inductive HC setting becomes relatively easy with MHCN. We train the model with the training set of NR-MNIST, then infer the results with the test set, and finally, the DP result is $96.54\\%$ . This result is numerically comparable with the result in Table 1 $(98.71\\%)$ . The ability of inductive HC may help improve the performance, e.g., transfer learning.", + "bbox": [ + 496, + 671, + 890, + 792 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.6. Parameter Sensitivity Analysis", + "text_level": 1, + "bbox": [ + 498, + 801, + 769, + 816 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Trade-off efficient $\\alpha$ . To start with, we focus on the choice of the trade-off efficient $\\alpha$ . By fixing the other hyperparameters, we investigate how the $\\alpha$ parameter balances the effects of reconstruction and alignment loss components for multi-view learning. We show the DP result of different", + "bbox": [ + 496, + 824, + 890, + 898 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "16532", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/f8448c59cbb99f670b254d45d552b1bb5b6ba2c93750cd75d7651e35ec40eb86.jpg", + "image_caption": [ + "Figure 5: $\\alpha$ sensitivity analysis" + ], + "image_footnote": [], + "bbox": [ + 80, + 89, + 464, + 244 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "$\\alpha$ values in a range between 0.0 and 1.0. As shown in Figure 5, with the increase of $\\alpha$ values, the quality of the final tree structures consistently stabilizes at an optimal level on all datasets. When $\\alpha = 0$ , the performance of HC gets near the lowest point, especially on MNIST-USPS, BBC-Sport, Multi-Fashion, and NR-MNSIT datasets. The principal reason is that in MHCN, the consistency across all views is achieved via the multi-view alignment loss, which is much essential to capture view-common meaningful semantics and further boost the final clustering trees.", + "bbox": [ + 75, + 297, + 467, + 449 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Temperature parameters $\\tau_{\\mathrm{align}}$ and $\\tau_{\\mathrm{uni}}$ . Similarly, with the other hyperparameters fixed, we present the DP results on all datasets by varying $\\tau_{\\mathrm{align}}$ and $\\tau_{\\mathrm{uni}}$ from 0.0 to 5.0. As shown in Figure 6, both $\\tau_{\\mathrm{align}}$ and $\\tau_{\\mathrm{uni}}$ set to around 1.0 achieve optimal performance on MNIST-USPS, BDGP, BBCSport, Multi-Fashion, and NR-MNIST datasets, while the HC performance on Caltech and COIL-20 datasets are more promising with $\\tau_{\\mathrm{align}} = \\tau_{\\mathrm{uni}} = 0.5$ . Besides, the model is more robust to changes of $\\tau_{\\mathrm{align}}$ .", + "bbox": [ + 75, + 450, + 467, + 585 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "4.7. Case Study", + "text_level": 1, + "bbox": [ + 76, + 595, + 199, + 611 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In addition to quantitative analysis, we qualitatively examine the quality of the final MVHC tree structures learned by our method. We take a truncated sub-tree of the complete Multi-Fashion tree as an example in Figure 4, where more similar leaf nodes are merged together earlier in the tree structure, guaranteeing explicit hierarchical partitioning. We can observe that more similar leaf nodes are merged together earlier in the tree structure, e.g., categories Shirt and T-Shirt/Top, while less similar products are merged together at higher LCA, e.g., categories Shirt and Trouser, or categories Bag and Trouser. Therefore, MHCN is capable of guaranteeing meaningful fine-grained hierarchical partitioning with high interpretability for the multi-view data.", + "bbox": [ + 75, + 619, + 467, + 815 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion & Future Work", + "text_level": 1, + "bbox": [ + 76, + 829, + 330, + 845 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this work, we present a novel one-stage framework MHCN to solve the multi-view hierarchical clustering problem. With the help of the hyperbolic model of the Poincaré", + "bbox": [ + 76, + 854, + 467, + 900 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/2227b53728230b7cf32a6901b571a50b52889213861a2ffffbf4fd30a52d6231.jpg", + "image_caption": [ + "(a) MNIST-USPS" + ], + "image_footnote": [], + "bbox": [ + 501, + 99, + 696, + 162 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/230f3dad9f90ed092e7cf5cc83fe5c5bac6b27bc1a088341e5002f9342e2ac67.jpg", + "image_caption": [ + "(b) BDGP" + ], + "image_footnote": [], + "bbox": [ + 697, + 101, + 890, + 162 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/ceda2cd50902ef1edc37a3444bedfdd9608e1777df74820a9e1c1401bc5cd7b6.jpg", + "image_caption": [ + "(c) Caltech" + ], + "image_footnote": [], + "bbox": [ + 501, + 191, + 697, + 252 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/14c79c7887b8928bc55546b9a46c9d9ec100cc04af2d239bd65faba546f9ef7a.jpg", + "image_caption": [ + "(d) COIL-20" + ], + "image_footnote": [], + "bbox": [ + 700, + 191, + 890, + 252 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/620ee05bb04673a7ebed7083552168fa3d90c503462abd264c41302b90b1f7ff.jpg", + "image_caption": [ + "(e) BBCSport" + ], + "image_footnote": [], + "bbox": [ + 501, + 280, + 697, + 340 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/7d03a7770de56127019df89a871dddda191749c90cc50fcbd32d919190dc7e2e.jpg", + "image_caption": [ + "(f) Multi-Fashion" + ], + "image_footnote": [], + "bbox": [ + 700, + 281, + 890, + 340 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/37d1ae9f38436c608d377fa1c78d2a750c3c332108af97b89e02ce9907bf536b.jpg", + "image_caption": [ + "(g) NR-MNIST", + "Figure 6: $\\tau_{\\mathrm{align}}$ and $\\tau_{\\mathrm{uni}}$ sensitivity analysis" + ], + "image_footnote": [], + "bbox": [ + 598, + 369, + 794, + 431 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "ball, we conduct our multi-view representation learning via multiple hyperbolic autoencoders, where the exponential map of each encoder and its inverse logarithm map of each decoder generalize the extracted latent hierarchies to hyperbolic space efficiently. Additionally, we introduce how to promote the final hierarchical clustering tree from the learned hyperbolic representations by jointly optimizing our designed loss functions, including the multi-view alignment loss for view-common information, the reconstruction loss for view-private information, and the hyperbolic uniformity loss for more balanced embedding distribution on the Poincaré ball. Extensive experiments on seven widespread multi-view datasets demonstrate our method achieves state-of-the-art hierarchical clustering performance. In the future, we expect to improve our method with a more general scheme to better learn the different effects of consistency and complementarity of different multi-view datasets.", + "bbox": [ + 496, + 503, + 890, + 760 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgments", + "text_level": 1, + "bbox": [ + 500, + 777, + 658, + 794 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work was partially supported by the National Key Research and Development Program of China (No. 2018AAA0100204), a key program of fundamental research from Shenzhen Science and Technology Innovation Commission (No. JCYJ20200109113403826), the Major Key Project of PCL (No. 2022ZD0115301), and an Open Research Project of Zhejiang Lab (NO.2022RC0AB04).", + "bbox": [ + 496, + 801, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "16533", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 174, + 106 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] MohammadHossein Bateni, Soheil Behnezhad, Mahsa Derakhshan, MohammadTaghi Hajiaghayi, Raimondas Kiveris, Silvio Lattanzi, and Vahab Mirrokni. Affinity clustering: Hierarchical clustering at scale. In NeurIPS, pages 6864-6874, 2017.", + "[2] Eugenio Beltrami. Teoria fondamentale degli spazii di curvatura costante. Annali di Matematica Pura ed Applicata (1867-1897), 2(1):232-255, 1868.", + "[3] Xiao Cai, Feiping Nie, and Heng Huang. Multi-view k-means clustering on big data. In *IJCAI*, pages 2598-2604, 2013.", + "[4] James W Cannon, William J Floyd, Richard Kenyon, Walter R Parry, et al. Hyperbolic geometry. Flavors of geometry, 31(59-115):2, 1997.", + "[5] Ines Chami, Albert Gu, Vaggos Chatziafratis, and Christopher Ré. From trees to continuous embeddings and back: Hyperbolic hierarchical clustering. In NeurIPS, pages 15065-15076, 2020.", + "[6] Ines Chami, Zhitao Ying, Christopher Ré, and Jure Leskovec. Hyperbolic graph convolutional neural networks. In NeurIPS, pages 4869-4880, 2019.", + "[7] Vaggos Chatziafratis, Rad Niazadeh, and Moses Charikar. Hierarchical clustering with structural constraints. In ICML, pages 774-783. PMLR, 2018.", + "[8] Kamalika Chaudhuri, Sham M Kakade, Karen Livescu, and Karthik Sridharan. Multi-view clustering via canonical correlation analysis. In ICML, pages 129-136, 2009.", + "[9] Giovanni Chierchia and Benjamin Perret. Ultrametric fitting by gradient descent. Journal of Statistical Mechanics: Theory and Experiment, 2020(12):124004, 2020.", + "[10] Vincent Cohen-Addad, Varun Kanade, Frederik Mallmann-Trenn, and Claire Mathieu. Hierarchical clustering: Objective functions and algorithms. Journal of the ACM (JACM), 66(4):1-42, 2019.", + "[11] Henry Cohn and Abhinav Kumar. Universally optimal distribution of points on spheres. Journal of the American Mathematical Society, 20(1):99-148, 2007.", + "[12] Shuyang Dai, Zhe Gan, Yu Cheng, Chenyang Tao, Lawrence Carin, and Jingjing Liu. Apo-vae: Text generation in hyperbolic space. arXiv preprint arXiv:2005.00054, 2020.", + "[13] Navneet Dalal and Bill Triggs. Histograms of oriented gradients for human detection. In CVPR, volume 1, pages 886-893. IEEE, 2005.", + "[14] Sanjoy Dasgupta. A cost function for similarity-based hierarchical clustering. In STOC, pages 118-127, 2016.", + "[15] Tim R Davidson, Luca Falorsi, Nicola De Cao, Thomas Kipf, and Jakub M Tomczak. Hyperspherical variational autoencoders. arXiv preprint arXiv:1804.00891, 2018.", + "[16] Delbert Dueck and Brendan J Frey. Non-metric affinity propagation for unsupervised image categorization. In ICCV, pages 1-8, 2007.", + "[17] Joseph Felsenstein and Joseph Felenstein. Inferring phylogenies, volume 2. Sinauer associates Sunderland, MA, 2004.", + "[18] Fangxiang Feng, Xiaojie Wang, and Ruifan Li. Cross-modal retrieval with correspondence autoencoder. In Proceedings of the 22nd ACM international conference on Multimedia, pages 7-16, 2014.", + "[19] Sylvestre Gallot, Dominique Hulin, and Jacques Lafontaine." + ], + "bbox": [ + 78, + 114, + 468, + 895 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Riemannian geometry, volume 2. Springer, 1990.", + "[20] Octavian Ganea, Gary Bécigneul, and Thomas Hofmann. Hyperbolic neural networks. In NeurIPS, volume 31, 2018.", + "[21] Mina GhadimiAtigh, Julian Schoep, Erman Acar, Nanne van Noord, and Pascal Mettes. Hyperbolic image segmentation. arXiv preprint arXiv:2203.05898, 2022.", + "[22] Zoubin Ghahramani, Michael Jordan, and Ryan P Adams. Tree-structured stick breaking for hierarchical data. In NeurIPS, volume 23, 2010.", + "[23] Kamran Ghasedi Dizaji, Amirhossein Herandi, Cheng Deng, Weidong Cai, and Heng Huang. Deep clustering via joint convolutional autoencoder embedding and relative entropy minimization. In ICCV, pages 5736-5745, 2017.", + "[24] Prasoon Goyal, Zhiting Hu, Xiaodan Liang, Chenyu Wang, and Eric P Xing. Nonparametric variational auto-encoders for hierarchical representation learning. In ICCV, pages 5094–5102, 2017.", + "[25] Katherine A Heller and Zoubin Ghahramani. Bayesian hierarchical clustering. In ICML, pages 297-304, 2005.", + "[26] Joy Hsu, Jeffrey Gu, Gong Wu, Wah Chiu, and Serena Yeung. Capturing implicit hierarchical structure in 3d biomedical images with self-supervised hyperbolic representations. In NeurIPS, pages 5112-5123, 2021.", + "[27] Shudong Huang, Yixi Liu, Yazhou Ren, Ivor W Tsang, Zenglin Xu, and Jiancheng Lv. Learning smooth representation for multi-view subspace clustering. In Proceedings of the 30th ACM International Conference on Multimedia, pages 3421-3429, 2022.", + "[28] Anil K Jain, M Narasimha Murty, and Patrick J Flynn. Data clustering: a review. ACM computing surveys (CSUR), 31(3):264-323, 1999.", + "[29] Yangbangyan Jiang, Qianqian Xu, Zhiyong Yang, Xiaochun Cao, and Qingming Huang. Dm2c: Deep mixed-modal clustering. In NeurIPS, pages 5880-5890, 2019.", + "[30] Zhao Kang, Guoxin Shi, Shudong Huang, Wenyu Chen, Xiaorong Pu, Joey Tianyi Zhou, and Zenglin Xu. Multi-graph fusion for multi-view spectral clustering. Knowledge-Based Systems, 189:105102, 2020.", + "[31] Ari Kobren, Nicholas Monath, Akshay Krishnamurthy, and Andrew McCallum. A hierarchical algorithm for extreme clustering. In KDD, pages 255-264, 2017.", + "[32] John M Lee. Smooth manifolds. In Introduction to Smooth Manifolds, pages 1-31. Springer, 2013.", + "[33] Ruihuang Li, Changqing Zhang, Huazhu Fu, Xi Peng, Tianyi Zhou, and Qinghua Hu. Reciprocal multi-layer subspace learning for multi-view clustering. In ICCV, pages 8172-8180, 2019.", + "[34] Yingming Li, Ming Yang, and Zhongfei Zhang. A survey of multi-view representation learning. TKDE, 31(10):1863-1883, 2018.", + "[35] Zhaoyang Li, Qianqian Wang, Zhiqiang Tao, Quanxue Gao, and Zhaohua Yang. Deep adversarial multi-view clustering network. In IJCAI, pages 2952-2958, 2019.", + "[36] Dongdong Lin, Jigang Zhang, Jingyao Li, Chao Xu, Hong-Wen Deng, and Yu-Ping Wang. An integrative imputation method based on multi-omics datasets. BMC bioinformatics, 17(1):1-12, 2016.", + "[37] Fangfei Lin, Bing Bai, Kun Bai, Yazhou Ren, Peng Zhao, and Zenglin Xu. Contrastive multi-view hyperbolic hierarchical clustering. In IJCAI, pages 3250-3256, 2022." + ], + "bbox": [ + 501, + 93, + 890, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "16534", + "bbox": [ + 480, + 945, + 519, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[38] Bulou Liu, Bing Bai, Weibang Xie, Yiwen Guo, and Hao Chen. Task-optimized user clustering based on mobile app usage for cold-start recommendations. In KDD, pages 3347–3356, 2022.", + "[39] Jiyuan Liu, Xinwang Liu, Yuexiang Yang, Li Liu, Siqi Wang, Weixuan Liang, and Jiangyong Shi. One-pass multi-view clustering for large-scale data. In ICCV, pages 12344-12353, 2021.", + "[40] Weiyang Liu, Rongmei Lin, Zhen Liu, Lixin Liu, Zhiding Yu, Bo Dai, and Le Song. Learning towards minimum hyperspherical energy. In NeurIPS, volume 31, 2018.", + "[41] Shirui Luo, Changqing Zhang, Wei Zhang, and Xiaochun Cao. Consistent and specific multi-view subspace clustering. In AAAI, pages 3730-3737, 2018.", + "[42] Emile Mathieu, Charline Le Lan, Chris J Maddison, Ryota Tomioka, and Yee Whye Teh. Continuous hierarchical representations with poincaré variational auto-encoders. In NeurIPS, volume 32, 2019.", + "[43] Nicholas Monath, Manzil Zaheer, Daniel Silva, Andrew McCallum, and Amr Ahmed. Gradient-based hierarchical clustering using continuous representations of trees in hyperbolic space. In KDD, pages 714-722, 2019.", + "[44] Fionn Murtagh and Pedro Contreras. Algorithms for hierarchical clustering: an overview. Wiley Interdisciplinary Reviews: Data Mining and Knowledge Discovery, 2(1):86-97, 2012.", + "[45] Yoshihiro Nagano, Shoichiro Yamaguchi, Yasuhiro Fujita, and Masanori Koyama. A differentiable gaussian-like distribution on hyperbolic space for gradient-based learning. CoRR, abs/1902.02992, 2019.", + "[46] Stanislav Naumov, Grigory Yaroslavl'tsev, and Dmitrii Avdiukhin. Objective-based hierarchical clustering of deep embedding vectors. In AAAI, pages 9055-9063, 2021.", + "[47] Maximillian Nickel and Douwe Kiela. Poincaré embeddings for learning hierarchical representations. In NeurIPS, pages 6338-6347, 2017.", + "[48] Aude Oliva and Antonio Torralba. Modeling the shape of the scene: A holistic representation of the spatial envelope. International journal of computer vision, 42(3):145-175, 2001.", + "[49] Erlin Pan and Zhao Kang. Multi-view contrastive graph clustering. In NeurIPS, volume 34, 2021.", + "[50] Jiwoong Park, Junho Cho, Hyung Jin Chang, and Jin Young Choi. Unsupervised hyperbolic representation learning via message passing auto-encoders. In CVPR, pages 5516–5526, 2021.", + "[51] Sakshi Patel, Shivani Sihmar, and Aman Jatain. A study of hierarchical clustering algorithms. In 2015 2nd international conference on computing for sustainable global development (INDIACom), pages 537-541. IEEE, 2015.", + "[52] Wei Peng, Tuomas Varanka, Abdelrahman Mostafa, Henglin Shi, and Guoying Zhao. Hyperbolic deep neural networks: A survey. arXiv preprint arXiv:2101.04562, 2021.", + "[53] Xi Peng, Zhenyu Huang, Jiancheng Lv, Hongyuan Zhu, and Joey Tianyi Zhou. Comic: Multi-view clustering without parameter selection. In ICML, pages 5092-5101, 2019.", + "[54] Peter Petersen. Riemannian geometry, volume 171. Springer, 2006.", + "[55] Ryohei Shimizu, Yusuke Mukuta, and Tatsuya Harada." + ], + "bbox": [ + 78, + 90, + 468, + 887 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Hyperbolic neural networks++. arXiv preprint arXiv:2006.08210, 2020.", + "[56] Su-Jin Shin, Kyungwoo Song, and Il-Chul Moon. Hierarchically clustered representation learning. In AAAI, pages 5776-5783, 2020.", + "[57] Huayi Tang and Yong Liu. Deep safe incomplete multi-view clustering: Theorem and algorithm. In International Conference on Machine Learning, pages 21090-21110. PMLR, 2022.", + "[58] Yee Teh, Hal Daume III, and Daniel M Roy. Bayesian agglomerative clustering with coalescents. In NeurIPS, volume 20, 2007.", + "[59] Daniel J Trosten, Sigurd Lokse, Robert Jenssen, and Michael Kampffmeyer. Reconsidering representation alignment for multi-view clustering. In CVPR, pages 1255-1265, 2021.", + "[60] Abraham Albert Ungar. A gyrovector space approach to hyperbolic geometry. Synthesis Lectures on Mathematics and Statistics, 1(1):1-194, 2008.", + "[61] Dingkang Wang and Yusu Wang. An improved cost function for hierarchical cluster trees. Journal of Computational Geometry, 11(1):283-331, 2020.", + "[62] Tongzhou Wang and Phillip Isola. Understanding contrastive representation learning through alignment and uniformity on the hypersphere. In ICML, pages 9929-9939. PMLR, 2020.", + "[63] Weiran Wang, Raman Arora, Karen Livescu, and Jeff Bilmes. On deep multi-view representation learning. In ICML, pages 1083-1092, 2015.", + "[64] Junyuan Xie, Ross Girshick, and Ali Farhadi. Unsupervised deep embedding for clustering analysis. In ICML, pages 478-487. PMLR, 2016.", + "[65] Jie Xu, Yazhou Ren, Guofeng Li, Lili Pan, Ce Zhu, and Zenglin Xu. Deep embedded multi-view clustering with collaborative training. Information Sciences, pages 279-290, 2021.", + "[66] Jie Xu, Yazhou Ren, Huayi Tang, Xiaorong Pu, Xiaofeng Zhu, Ming Zeng, and Lifang He. Multi-vae: Learning disentangled view-common and view-peculiar visual representations for multi-view clustering. In ICCV, pages 9234–9243, 2021.", + "[67] Jie Xu, Huayi Tang, Yazhou Ren, Liang Peng, Xiaofeng Zhu, and Lifang He. Multi-level feature learning for contrastive multi-view clustering. In CVPR, pages 16051-16060, 2022.", + "[68] Qinghai Zheng, Jihua Zhu, and Shuangxun Ma. Multi-view hierarchical clustering. arXiv preprint arXiv:2010.07573, 2020." + ], + "bbox": [ + 501, + 92, + 890, + 696 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "16535", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/803b20b8-8ea9-4642-8b2e-1e4d0ac18614_model.json b/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/803b20b8-8ea9-4642-8b2e-1e4d0ac18614_model.json new file mode 100644 index 0000000000000000000000000000000000000000..805a2b74c6d44c007ae54f1cb13c49944dc01bb4 --- /dev/null +++ b/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/803b20b8-8ea9-4642-8b2e-1e4d0ac18614_model.json @@ -0,0 +1,2642 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.253, + 0.131, + 0.72, + 0.177 + ], + "angle": 0, + "content": "MHCN: A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering" + }, + { + "type": "text", + "bbox": [ + 0.115, + 0.203, + 0.856, + 0.275 + ], + "angle": 0, + "content": "Fangfei Lin\\(^{1,3*}\\), Bing Bai\\(^{3\\dagger}\\), Yiwen Guo\\(^{6\\dagger}\\), Hao Chen\\(^{4}\\), Yazhou Ren\\(^{1}\\), Zenglin Xu\\(^{2,5\\dagger}\\) \n\\(^{1}\\)University of Electronic Science and Technology of China, China \\(^{2}\\)Peng Cheng Lab, China \n\\(^{3}\\)Tencent Security Big Data Lab, China \\(^{4}\\)University of California, Davis, USA \n\\(^{5}\\)Harbin Institute of Technology Shenzhen, China \\(^{6}\\)Independent Researcher" + }, + { + "type": "text", + "bbox": [ + 0.202, + 0.277, + 0.768, + 0.293 + ], + "angle": 0, + "content": "{phoebe.lin1108,guoyiwen89,zenglin}@gmail.com,icebai@tencent.com" + }, + { + "type": "text", + "bbox": [ + 0.307, + 0.296, + 0.662, + 0.309 + ], + "angle": 0, + "content": "chen@ucdavis.edu, yazhou. ren@uestc.edu.cn" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.345, + 0.314, + 0.361 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.377, + 0.474, + 0.74 + ], + "angle": 0, + "content": "Multi-view hierarchical clustering (MCHC) plays a pivotal role in comprehending the structures within multi-view data, which hinges on the skillful interaction between hierarchical feature learning and comprehensive representation learning across multiple views. However, existing methods often overlook this interplay due to the simple heuristic agglomerative strategies or the decoupling of multi-view representation learning and hierarchical modeling, thus leading to insufficient representation learning. To address these issues, this paper proposes a novel Multi-view Hierarchical Clustering Network (MHCN) model by performing simultaneous multi-view learning and hierarchy modeling. Specifically, to uncover efficient tree-like structures among all views, we derive multiple hyperbolic autoencoders with latent space mapped onto the Poincaré ball. Then, the corresponding hyperbolic embeddings are further regularized to achieve the multi-view representation learning principles for both view-common and view-private information, and to ensure hyperbolic uniformity with a well-balanced hierarchy for better interpretability. Extensive experiments on real-world and synthetic multi-view datasets have demonstrated that our method can achieve state-of-the-art hierarchical clustering performance, and empower the clustering results with good interpretability." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.766, + 0.21, + 0.782 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.791, + 0.47, + 0.868 + ], + "angle": 0, + "content": "Clustering is one of the fundamental research topics in data analysis [28, 44, 51]. With the advances in data acquisition, lots of real-world data could be presented by multiple views, e.g., different visual descriptors like GIST [48] + Histogram of Oriented Gradients (HOG) [13] + other" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.343, + 0.891, + 0.535 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.544, + 0.895, + 0.697 + ], + "angle": 0, + "content": "Figure 1: Comparison between prior MVHC methods, i.e., MHC and CMHHC, versus our proposed MHCN. (a) MHC calculates the average cosine distance matrix of all views and agglomerates the nearest neighbors according to the simply-aligned similarity matrix. (b) CMHHC performs multi-view alignment and similarity learning in the Euclidean space, and hierarchical clustering in hyperbolic space, separately. (c) Our MHCN, a one-stage pipeline, directly aligns the latent hierarchies on different Poincaré balls, leading to more effective MVHC trees." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.895, + 0.903 + ], + "angle": 0, + "content": "deep features [53] for an image. Multiple views contain both congruent and incongruent information, which can be leveraged to explore potential consistency and complementarity across views and provide more comprehensive latent representations to facilitate downstream tasks, especially for unsupervised learning. This leads to the prevalence of multi-view clustering including multi-view partitional clustering [29, 35, 39, 49, 59] and multi-view hierarchical clustering [37, 68]. Aiming for high interpretability, multi-view hierarchical clustering is particularly appealing in the analysis of multi-view data at various levels of gran" + }, + { + "type": "page_footnote", + "bbox": [ + 0.095, + 0.875, + 0.44, + 0.888 + ], + "angle": 0, + "content": "*This work was done when Fangfei Lin was an intern at Tencent." + }, + { + "type": "page_footnote", + "bbox": [ + 0.098, + 0.888, + 0.227, + 0.9 + ], + "angle": 0, + "content": "† Corresponding authors." + }, + { + "type": "list", + "bbox": [ + 0.095, + 0.875, + 0.44, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16525" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.471, + 0.182 + ], + "angle": 0, + "content": "ularity. For instance, gene expression analysis [36] integrates multi-omics data and clusters cells into an organization/organ/system hierarchy. Besides, species trees [17], gathering animals by their physical appearances, sounds, or other features, reflect the hierarchical organization in phylogenetic inference." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.187, + 0.471, + 0.549 + ], + "angle": 0, + "content": "Despite these merits, there are still significant limitations in existing multi-view hierarchical clustering methods. As shown in Figure 1, existing models for solving the MVHC problem include the discrete linkage-based method Multiview Hierarchical Clustering (MHC) [68], and the continuous deep neural network-based Contrastive Multi-view Hyperbolic Hierarchical Clustering (CMHHC) [37]. As a seminal work for MVHC, shallow MHC partitions multi-view data at multiple levels through the cosine distance integration and the nearest neighbor agglomeration components. However, without applying deep representation learning, this method simply considers the mean latent feature vectors as the common representations of all views. Thus, it cannot fully capture the consistency and complementarity among different views, leading to degenerated HC performance, especially on complicated real-world datasets. The two-stage deep model CMHHC integrates a multi-view alignment learning module, an aligned feature similarity learning module, and a continuous hyperbolic hierarchical clustering module. However, CMHHC takes into account two independent geometry settings, treating multiview learning in the Euclidean space and HC in hyperbolic space, enlarging the gap between the two processes. Thus, the performance may still be suboptimal." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.554, + 0.47, + 0.902 + ], + "angle": 0, + "content": "To address these issues, this paper proposes the Multi-view Hierarchical Clustering Network (MHCN), as sketched in Figure 2. Taking the desired MVHC tree structures into consideration, we make corresponding designs for MHCN as follows. Firstly, drawing inspiration from the recent success of latent hyperbolic anatomy [42, 52], which excels in modeling hierarchies with minimal distortion, we incorporate multiple hyperbolic autoencoders to capture the inherent hierarchies present in different views. Secondly, considering multi-view consistent and complementary principles [34, 66], we design the multi-view alignment loss between two arbitrary views to discover the view-common information, and use the reconstruction loss to retain the view-private information, respectively. Thirdly, uniformly-distributed hyperbolic embeddings on the Poincaré ball create well-balanced trees, leading to more interpretable semantics compared with skewed ones. In order to improve interpretability in clustering trees, we encourage the balanced hierarchy construction via a hyperbolic uniformity loss, which facilitates learning such hyperbolic embeddings. In this way, MHCN provides explicit guidance for ensuring the quality of the tree structure and integrates multi-view representation learning and hierarchy discovery" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.227 + ], + "angle": 0, + "content": "processes on hyperbolic manifolds with hierarchy-friendly hyperbolic autoencoders. As the pioneering one-stage solution for the MVHC problem, the MHCN model collectively optimizes the three objectives with mini-batch training. Thus, large datasets can be efficiently processed. After obtaining the optimal hyperbolic hierarchical representations for unseen data with trained neural networks, MHCN can decode back to the underlying tree structures, making inductive hierarchical clustering possible." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.228, + 0.892, + 0.257 + ], + "angle": 0, + "content": "Different from existing MVHC models, our contributions are summarized as follows." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.263, + 0.892, + 0.338 + ], + "angle": 0, + "content": "- We analyze the multi-view hierarchical clustering problem and propose a novel hyperbolic neural network-based model to tackle the problem, where the latent space is grafted on the Poincaré ball of hyperbolic space for explicit hierarchical structures." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.346, + 0.892, + 0.407 + ], + "angle": 0, + "content": "- We introduce three objectives to facilitate the final multi-view hierarchical clustering trees with desired properties, i.e., a multi-view alignment loss, a reconstruction loss, and a hyperbolic uniformity loss." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.415, + 0.892, + 0.459 + ], + "angle": 0, + "content": "- We conduct extensive experiments to show the superiority of MHCN compared with other multi-view HC methods in terms of both effectiveness and scalability." + }, + { + "type": "list", + "bbox": [ + 0.519, + 0.263, + 0.892, + 0.459 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.475, + 0.642, + 0.491 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.5, + 0.719, + 0.516 + ], + "angle": 0, + "content": "2.1. Hierarchical Clustering" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.524, + 0.892, + 0.749 + ], + "angle": 0, + "content": "Bottom-up linkage algorithms for solving HC are simple and easy to implement, which recursively merge similar data points to build larger cluster sub-trees until a complete dendrogram appears [10, 31]. Typical agglomerative heuristics include Single Linkage, Complete Linkage, Average Linkage, and Ward Linkage [10]. While these traditional algorithms are widely used in practice, there is a limit to fit continuous optimization due to their inherent discreteness [14, 43, 61]. Hence, there have been more attempts at gradient-based HC through embedding methods recently [5, 9, 24, 46, 56]. For example, UFit [9] proposed a gradient-based fitting framework over ultrametric. Besides, similarity-based HypHC [5] directly relaxed Dasgupta's cost with the aid of the continuous form of hyperbolic leaf nodes and lowest common ancestors (LCAs)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.751, + 0.892, + 0.84 + ], + "angle": 0, + "content": "In contrast to the above HC methods, our unified framework is multi-view data-oriented, which can be optimized continuously via specifically-designed hierarchical clustering objectives. Also, little previous research pays close attention to the balancing property of clustering trees, which is one of the mainly-addressed spots in our method." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.848, + 0.706, + 0.864 + ], + "angle": 0, + "content": "2.2. Multi-view Clustering" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Existing multi-view clustering (MVC) methods can be roughly classified into four categories, namely, canon-" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.52, + 0.957 + ], + "angle": 0, + "content": "16526" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.159, + 0.089, + 0.817, + 0.356 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.366, + 0.892, + 0.489 + ], + "angle": 0, + "content": "Figure 2: Overview of the proposed MHCN (taking two views as an example). MHCN assigns a hyperbolic autoencoder to each view, with the latent space grafted on the Poincaré ball for explicit hierarchies, where the exponential mapping function \\(\\exp_0\\) follows the hyperbolic encoder, and the hyperbolic decoder connects behind the logarithm mapping function \\(\\log_0\\). The whole model is trained with the three joint learning objectives: (1) the multi-view alignment learning aims to align the hyperbolic embeddings \\(z_i^1\\) and \\(z_i^2\\), (2) the reconstruction for HAE is used to project the complementary information in each view into the latent space, and (3) the hyperbolic uniformity learning guarantees \\(z_i^1\\) and \\(z_i^2\\) to distribute uniformly on the corresponding Poincaré balls, respectively. After \\(\\beta\\)-fusion, the final MVHC tree can be decoded from the common hyperbolic representations." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.514, + 0.47, + 0.741 + ], + "angle": 0, + "content": "ical correlation analysis-based [8], matrix factorization-based [3], subspace-based [27, 33] and graph-based [30] methods. Recently, deep MVC methods have been developed increasingly [35, 38, 49, 53, 59, 67]. However, most methods are limited to partitional clustering. The high computational complexities of these methods hinder the practicability and development of multi-view hierarchical clustering. To this end, research about MVHC has gradually emerged. Shallow MHC [68] roughly averages the cosine distance graphs for common latent features, which cannot achieve consistency of all views. A recent two-stage deep method CMHHC [37] presents an MVHC tree over aligned common representations through three modules, i.e., multiview alignment learning, unsupervised metric learning, and hyperbolic hierarchical clustering." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.742, + 0.47, + 0.817 + ], + "angle": 0, + "content": "Unlike CMHHC, which regards multi-view representation learning and hierarchical clustering as two separate stages, our method unifies them into a one-stage training pipeline, where they can reinforce each other for naturally contributing to the final HC trees." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.831, + 0.262, + 0.848 + ], + "angle": 0, + "content": "2.3. Hyperbolic Models" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.47, + 0.901 + ], + "angle": 0, + "content": "There is extensive literature on hierarchical models conducted in the Euclidean space and its applications [22, 25, 58]. However, suffering from the inherent discrete na" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.514, + 0.892, + 0.667 + ], + "angle": 0, + "content": "ture of trees, the Euclidean hierarchical models have difficulty in constructing the hierarchical structure of data explicitly, while hyperbolic models can. The underlying reason is that the exponential growth of the volume in hyperbolic space with its radius is analogous to the exponential growth of the number of leaves in a tree with its altitude, which is infeasible in the Euclidean space [43]. Thus, there has been an increasing interest in the generalization of hyperbolic neural networks to learn hyperbolic representations [6, 20, 26, 42, 50, 55]." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.679, + 0.591, + 0.695 + ], + "angle": 0, + "content": "3. Method" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.892, + 0.84 + ], + "angle": 0, + "content": "In this part, we propose a hyperbolic neural network model for MVHC, termed as Multi-view Hierarchical Clustering Network (MHCN), as shown in Figure 2. For clarity, we first briefly review the background of hyperbolic geometry and a specific hyperbolic model, i.e., the Poincaré ball. Then, we describe the architecture of HAE, define what desired trees look like through specific loss functions, and introduce the decoding strategy. Lastly, we summarize the whole optimization process." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Let \\(\\{\\pmb{X}^m\\in \\mathbb{R}^{N\\times D_m}\\}_{m = 1}^M\\) be a multi-view dataset including \\(N\\) samples across \\(M\\) views, where each \\(\\pmb{x}_i^m\\in \\mathbb{R}^{D_m}\\) denotes the \\(i\\)-th instance of \\(D_{m}\\) dimension from the \\(m\\)-th view. Our target is to present a unified method for" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16527" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.123 + ], + "angle": 0, + "content": "clustering tree learning by searching over multi-view continuous hierarchical representations in hyperbolic space." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.135, + 0.218, + 0.15 + ], + "angle": 0, + "content": "3.1. Preliminaries" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.16, + 0.469, + 0.221 + ], + "angle": 0, + "content": "We first introduce the Riemannian geometry and the Poincaré ball model of hyperbolic geometry, with which we build the hyperbolic autoencoders for our model. A more detailed review can be found in the appendix." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.246, + 0.292, + 0.263 + ], + "angle": 0, + "content": "3.1.1 Riemannian Geometry" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.272, + 0.473, + 0.531 + ], + "angle": 0, + "content": "An \\(n\\)-dimensional manifold \\(\\mathcal{M}\\) [19, 54] is a real and smooth space, which can be locally approximated to a linear \\(n\\)-dimensional space \\(\\mathbb{R}^n\\) at each point \\(\\pmb{x} \\in \\mathcal{M}\\). For any point \\(\\pmb{x}\\) of the manifold \\(\\mathcal{M}\\), the corresponding local tangent space \\(\\mathcal{T}_x\\mathcal{M}\\), is the first order linear approximation of \\(\\mathcal{M}\\) around the point \\(\\pmb{x}\\). The related metric tensor \\(g_x: \\mathcal{T}_x\\mathcal{M} \\times \\mathcal{T}_x\\mathcal{M} \\to \\mathbb{R}\\) defines an inner product on \\(\\mathcal{T}_x\\mathcal{M}\\) and a Riemannian metric \\(g = (g_x)_{x \\in \\mathcal{M}}\\) is a set of such inner products on \\(\\mathcal{M}\\). In this way, a Riemannian manifold can be presented as a matching tuple \\((\\mathcal{M}, g)\\). With \\(g_x\\), the local geometric attributions of \\(\\mathcal{T}_x\\mathcal{M}\\) are accessible, and then the global distances can be achieved by integrating the local properties together. To project a tangent vector \\(z\\) in \\(\\mathcal{T}_x\\mathcal{M}\\) onto \\(\\mathcal{M}\\) along a geodesic with constant velocity, the exponential map \\(\\exp_x: \\mathcal{T}_x\\mathcal{M} \\to \\mathcal{M}\\) is given, and the inverse form is logarithmic map \\(\\log_x: \\mathcal{M} \\to \\mathcal{T}_x\\mathcal{M}\\) [20, 52, 55]. More detailed review is in the appendix." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.555, + 0.447, + 0.57 + ], + "angle": 0, + "content": "3.1.2 Poincaré Ball Model of Hyperbolic Geometry" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.581, + 0.47, + 0.779 + ], + "angle": 0, + "content": "Many studies [12, 21, 47] have demonstrated that data representations in most machine learning applications lie on a Riemannian manifold [32]. Later on, how to generalize neural networks to a Riemannian space has made remarkable progress [15, 42, 45]. An \\(n\\)-dimensional hyperbolic space \\(\\mathbb{H}^n\\) is an \\(n\\)-dimensional Riemannian manifold with constant negative curvature [2, 4]. We choose to perform our model on the \\(n\\)-dimensional Poincaré ball \\((\\mathbb{B}^n,g^{\\mathbb{B}})\\) with a constant negative curvature \\(-1\\), where \\(\\mathbb{B}^n = \\{\\pmb {x}\\in \\mathbb{R}^n:||\\pmb {x}||^2 < 1\\}\\) is an open ball of curvature \\(-1\\), and its hyperbolic metric tensor \\(g_{\\pmb{x}}^{\\mathbb{B}} = \\lambda_{\\pmb{x}}^{2}g^{E}\\) is conformal to the Euclidean one. \\(\\lambda_{\\pmb{x}}^{2} = \\frac{2}{1 - ||\\pmb{x}||^{2}}\\) is a conformal factor, and \\(g^{E} = I_{n}\\) denotes the dot product in the Euclidean space." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.78, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Given \\(z, z' \\in \\mathbb{B}^n\\) and \\(t \\in \\mathcal{T}_z\\mathbb{B}^n\\), the exponential map \\(\\exp_z: \\mathcal{T}_z\\mathbb{B}^n \\to \\mathbb{B}^n\\) and the logarithm map \\(\\log_z: \\mathbb{B}^n \\to \\mathcal{T}_z\\mathbb{B}^n\\) realize the projection from the Euclidean space onto the Poincaré ball and vice versa, respectively. To enable the mathematical operations for hyperbolic space models, the framework of gyrovector spaces provides the algebraic setting for the hyperbolic geometry. With the Möbius Addition \\(\\oplus\\) [60], the closed-form expressions of" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.092, + 0.768, + 0.108 + ], + "angle": 0, + "content": "\\(\\exp_z\\) and \\(\\log_z\\) are respectively given by" + }, + { + "type": "equation", + "bbox": [ + 0.516, + 0.115, + 0.892, + 0.156 + ], + "angle": 0, + "content": "\\[\n\\exp_ {z} (\\boldsymbol {t}) = \\boldsymbol {z} \\oplus \\left(\\tanh \\left(\\frac {\\lambda_ {z} \\| \\boldsymbol {t} \\|}{2}\\right) \\frac {\\boldsymbol {t}}{\\| \\boldsymbol {t} \\|}\\right), \\tag {1}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.515, + 0.151, + 0.86, + 0.183 + ], + "angle": 0, + "content": "\\[\n\\log_ {z} (z ^ {\\prime}) = \\frac {2}{\\lambda_ {z}} \\mathrm {a r c t a n h} (| | - z \\oplus z ^ {\\prime} | |) \\frac {- z \\oplus z ^ {\\prime}}{| | - z \\oplus z ^ {\\prime} | |}.\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.191, + 0.892, + 0.221 + ], + "angle": 0, + "content": "For the convenience in practice, \\( z \\) is usually set to the origin \\( \\mathbf{0} \\), so the \\( \\exp_z \\) and \\( \\log_z \\) can be simplified as" + }, + { + "type": "equation", + "bbox": [ + 0.586, + 0.228, + 0.892, + 0.269 + ], + "angle": 0, + "content": "\\[\n\\exp_ {\\mathbf {0}} (\\boldsymbol {t}) = \\tanh (| | \\boldsymbol {t} | |) \\frac {\\boldsymbol {t}}{| | \\boldsymbol {t} | |}), \\tag {2}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.585, + 0.263, + 0.808, + 0.295 + ], + "angle": 0, + "content": "\\[\n\\log_ {\\mathbf {0}} \\left(\\boldsymbol {z} ^ {\\prime}\\right) = \\operatorname {a r c t a n h} \\left(\\left| \\left| \\boldsymbol {z} ^ {\\prime} \\right| \\right|\\right) \\frac {\\boldsymbol {z} ^ {\\prime}}{\\left| \\left| \\boldsymbol {z} ^ {\\prime} \\right| \\right|}.\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.303, + 0.892, + 0.365 + ], + "angle": 0, + "content": "By means of the above main operations \\(\\exp_0(t)\\) and \\(\\log_0(z')\\), MHCN is able to perform the basic transformations of the latent representations between the Euclidean space and the hyperbolic space." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.372, + 0.733, + 0.388 + ], + "angle": 0, + "content": "3.2. Hyperbolic Autoencoders" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.395, + 0.892, + 0.668 + ], + "angle": 0, + "content": "The conventional approach to learning useful representations is through a regular Euclidean autoencoder [18, 23, 64]. However, there has been significant interest in hierarchical representation learning using non-Euclidean geometry, specifically the hyperbolic space. This attention arises from the fact that the number of leaf nodes in tree structures increases exponentially with depth, mirroring the exponential growth of the hyperbolic surface area with its radius, while the growth in the Euclidean space is polynomial [6, 20, 52, 55]. As a result, we augment the standard autoencoder with hyperbolic geometry in the embedding space, and propose a novel multi-view hyperbolic model consisting of multiple hyperbolic autoencoders assigned for different views, shown in Figure 2. Each hyperbolic autoencoder's geometry-aware encoder and decoder are constructed via the introduced exponential and logarithmic map functions in Eq.(2). We show the detailed structures of the encoders and the decoders in the following." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.685, + 0.8, + 0.701 + ], + "angle": 0, + "content": "3.2.1 Encoder with the Exponential Map" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.708, + 0.892, + 0.83 + ], + "angle": 0, + "content": "With regard to the \\(m\\)-th view \\(\\pmb{X}^{m}\\), the encoder of \\(m\\)-th HAE, i.e., \\(f_{\\mathrm{enc}}(\\pmb{X}^{m};\\theta_{\\mathrm{enc}}^{m}): \\pmb{X}^{m} \\in \\mathbb{R}^{D_{m}} \\to \\pmb{Z}_{\\mathrm{hyp}}^{m} \\in \\mathbb{B}^{d}\\), is designed as a regular Euclidean encoder followed by the exponential map \\(\\exp_0(\\cdot)\\), along with which the output of the hyperbolic encoder is projected onto the Poincaré ball. \\(\\pmb{Z}_{\\mathrm{hyp}}^{m}\\) represents the \\(d\\)-dimensional hyperbolic latent code with explicit hierarchical patterns and \\(\\theta_{\\mathrm{enc}}^{m}\\) denotes the encoder parameters." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.847, + 0.79, + 0.863 + ], + "angle": 0, + "content": "3.2.2 Decoder with the Logarithm Map" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.892, + 0.904 + ], + "angle": 0, + "content": "Similar to the hyperbolic encoder, the decoder of the \\(m\\)-th HAE, \\(f_{\\mathrm{dec}}(\\pmb{X}^m;\\theta_{\\mathrm{dec}}^m): \\pmb{Z}_{\\mathrm{hyp}}^m \\in \\mathbb{B}^d \\to \\pmb{X}^m \\in \\mathbb{R}^{D_m}\\)" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16528" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.091, + 0.47, + 0.152 + ], + "angle": 0, + "content": "for the \\(m\\)-th view \\(\\mathbf{X}^m\\) which is parameterized by \\(\\theta_{\\mathrm{dec}}^m\\), is constituted of a regular Euclidean decoder preprocessed by the logarithm map \\(\\log_0(\\cdot)\\), projecting the latent hyperbolic features back to the Euclidean space." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.161, + 0.396, + 0.176 + ], + "angle": 0, + "content": "3.3. Loss Functions for Desired HC Trees" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.184, + 0.469, + 0.304 + ], + "angle": 0, + "content": "High-quality MVHC trees should: 1) preserve the intrinsic hierarchy of each view via learned hyperbolic embeddings, 2) make full use of multi-view complementary and consistent information to acquire common hierarchical representations, and 3) not increase hierarchies without strong necessity [1, 7, 14, 62]. In this section, based on the structure of multi-view HAEs, we design the total loss functions for our model to realize the above characteristics:" + }, + { + "type": "equation", + "bbox": [ + 0.195, + 0.318, + 0.469, + 0.333 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\mathrm {m v l}} + \\mathcal {L} _ {\\mathrm {u n i}}. \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.345, + 0.469, + 0.406 + ], + "angle": 0, + "content": "In our model, we jointly achieve the multi-view consistency and complementarity in the hyperbolic common-view space by optimizing the combined loss \\(\\mathcal{L}_{\\mathrm{mvl}}\\) of the multi-view alignment loss \\(\\mathcal{L}_{\\mathrm{align}}\\) and the reconstruction loss \\(\\mathcal{L}_{\\mathrm{rc}}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.167, + 0.418, + 0.469, + 0.433 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {m v l}} = \\alpha \\mathcal {L} _ {\\text {a l i g n}} + (1 - \\alpha) \\mathcal {L} _ {\\mathrm {r c}}, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.445, + 0.469, + 0.474 + ], + "angle": 0, + "content": "where \\(\\alpha\\) is a trade-off coefficient to balance the effects of consistency and complementarity for multi-view learning." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.476, + 0.469, + 0.641 + ], + "angle": 0, + "content": "Learning view-common consistency with the multi-view alignment loss. The extracted common representations \\(\\{Z_{\\mathrm{hyp}}^m = f_{\\mathrm{enc}}(X^m)\\}_{m=1}^M\\) are expected not only to uncover the complementary relationships among different views but also to contain sufficient consensus information of all views. To achieve consistency across multiple views, we apply distance and similarity-based alignment by conducting a multi-view alignment loss endowed on the hyperbolic embeddings. Here, we consider the cosine distance between two latent features \\(z_i^{m_1}\\) and \\(z_j^{m_2}\\) as the similarity measurement for multi-view alignment:" + }, + { + "type": "equation", + "bbox": [ + 0.156, + 0.651, + 0.469, + 0.688 + ], + "angle": 0, + "content": "\\[\n\\sin \\left(\\boldsymbol {z} _ {i} ^ {m _ {1}}, \\boldsymbol {z} _ {i} ^ {m _ {2}}\\right) = \\frac {\\left\\langle \\boldsymbol {z} _ {i} ^ {m _ {1}} , \\boldsymbol {z} _ {j} ^ {m _ {2}} \\right\\rangle}{\\left| \\left| \\boldsymbol {z} _ {i} ^ {m _ {1}} \\right| \\right| \\left| \\left| \\boldsymbol {z} _ {j} ^ {m _ {2}} \\right| \\right|}. \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.698, + 0.469, + 0.803 + ], + "angle": 0, + "content": "Supported by the conformality property of the Riemannian geometry, i.e., the Poincaré ball preserves the same angels as the Euclidean space, the computation of the cosine similarity in the Euclidean space is equal to that on the Poincaré ball [20, 55]. Besides, unlike the geodesic distances, values of the cosine distances are kept in a certain range, which is friendly to optimization processes." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.804, + 0.469, + 0.852 + ], + "angle": 0, + "content": "Then, the multi-view alignment loss between the hyperbolic embeddings of the same instance from any two views \\( Z_{\\mathrm{hyp}}^{m_1}, Z_{\\mathrm{hyp}}^{m_2} \\) is given by:" + }, + { + "type": "equation", + "bbox": [ + 0.122, + 0.863, + 0.469, + 0.904 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {a l i g n}} ^ {(m _ {1}, m _ {2})} = - \\frac {1}{N} \\sum_ {i = 1} ^ {N} \\sin \\left(\\boldsymbol {z} _ {i} ^ {m _ {1}}, \\boldsymbol {z} _ {i} ^ {m _ {2}}\\right) / \\tau_ {\\text {a l i g n}}, \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.167 + ], + "angle": 0, + "content": "where \\(\\tau_{\\mathrm{align}}\\) is used as a temperature parameter for the scaled distance function. Here, we notice that CMHHC [37] also serves to learn common representations. However, CMHHC aligns Euclidean features, while MHCN directly makes the corresponding hyperbolic embeddings closer." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.168, + 0.892, + 0.197 + ], + "angle": 0, + "content": "Therefore, the complete multi-view alignment loss across all view pairs is formulated as:" + }, + { + "type": "equation", + "bbox": [ + 0.566, + 0.205, + 0.892, + 0.247 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {a l i g n}} = \\sum_ {m _ {1} = 1} ^ {M} \\sum_ {m _ {2} = 1, m _ {1} \\neq m _ {2}} ^ {M} \\mathcal {L} _ {\\text {a l i g n}} ^ {(m _ {1}, m _ {2})}. \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.255, + 0.892, + 0.465 + ], + "angle": 0, + "content": "Learning view-private complementarity with the reconstruction loss of HAEs. In multi-view representation learning models, autoencoders are widely used for their impressive strengths, such as preserving the useful view-private information and preventing data points from collapsing to a small number of clusters [29, 67]. In our multi-view hierarchical clustering model, the learned representations by multiple HAEs consider the preservation of the local hierarchical structure within each view. This implies that similar instances from each view remain close to each other in the hyperbolic space, while the latent codes obtained from dissimilar instances remain distant from one another. To this end, the total reconstruction loss function of HAEs for multiple views is formulated as" + }, + { + "type": "equation", + "bbox": [ + 0.503, + 0.473, + 0.891, + 0.527 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {r c}} = \\sum_ {m = 1} ^ {M} \\mathcal {L} _ {\\mathrm {r c}} ^ {m} = \\sum_ {m = 1} ^ {M} \\frac {1}{N} \\sum_ {i = 1} ^ {N} \\left| \\left| \\boldsymbol {x} _ {i} ^ {m} - f _ {\\mathrm {d e c}} \\left(f _ {\\mathrm {e n c}} \\left(\\boldsymbol {x} _ {i} ^ {m}\\right)\\right) \\right| \\right| _ {2} ^ {2}, \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.528, + 0.892, + 0.555 + ], + "angle": 0, + "content": "where \\(\\mathcal{L}_{\\mathrm{rc}}^m\\) is the corresponding \\(m\\)-th view objective to reconstruct \\(\\pmb{X}^{m}\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.558, + 0.892, + 0.678 + ], + "angle": 0, + "content": "Learning tree balancing property with the hyperbolic uniformity loss. Through the multi-view alignment and reconstruction related to the Poincaré ball, our model obtains reliable multi-view representations and discovers the hierarchical structure of each view simultaneously. Last but not least, a hierarchical clustering tree with explicit balancing property provides fewer hierarchies and higher interpretability than skewed ones." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.679, + 0.892, + 0.768 + ], + "angle": 0, + "content": "Consequently, we leverage the uniformity of the hyperbolic embedding distribution located on the Poincaré ball to learn separable features and enhance the contribution of the balanced affinity. Concretely, considering the form of Gaussian potential kernel [11, 40], we define a hyperbolic uniformity objective based on the cosine distance as:" + }, + { + "type": "equation", + "bbox": [ + 0.509, + 0.776, + 0.891, + 0.818 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {u n i}} = \\sum_ {m = 1} ^ {M} \\frac {1}{N ^ {2}} \\sum_ {i = 1} ^ {N} \\sum_ {j = 1} ^ {N} \\log \\left(e ^ {- t \\left(- \\operatorname {s i m} \\left(\\boldsymbol {z} _ {i} ^ {m}, \\boldsymbol {z} _ {j} ^ {m}\\right) / \\tau_ {\\mathrm {u n i}}\\right)}\\right). \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.892, + 0.9 + ], + "angle": 0, + "content": "Still, the temperature parameter \\(\\tau_{\\mathrm{uni}}\\) is a scaling factor to the cosine distance. Intuitively, the hyperbolic uniformity loss encourages the latent hyperbolic embeddings to push farther away from each other and to benefit the uniform global distribution of embeddings on the Poincaré ball." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16529" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.091, + 0.468, + 0.108 + ], + "angle": 0, + "content": "3.4. From Hyperbolic Embeddings to Binary Trees" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.114, + 0.47, + 0.326 + ], + "angle": 0, + "content": "We first adopt \\(\\beta\\)-fusion [55] to concatenate the optimal hyperbolic embeddings from multiple views into the common-view space, to guarantee the concatenated norms maintain upper-bounded by the radius of the Poincaré ball. To output an intuitive HC tree from the common continuous hyperbolic representations on the Poincaré ball back to discrete HC trees with low error, we apply the decoding strategy proposed by [5], which realizes the underlying correspondence between the hyperbolic embeddings and the HC trees with low-error. This bottom-up decoding algorithm decodes the common hyperbolic embeddings by measuring the similarity of any two embeddings with the distance from their lowest common ancient (LCA) to the origin of the ball and merging more similar ones iteratively." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.336, + 0.277, + 0.352 + ], + "angle": 0, + "content": "3.5. Optimization Process" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.36, + 0.468, + 0.451 + ], + "angle": 0, + "content": "The whole optimization process of MHCN is summarized in the appendix. We train this model by adopting a one-stage pipeline of mini-batch gradient descent, making our method feasible to scale up to large-scale scenarios. Concretely, the integrated framework of multiple HAEs is optimized collectively with the \\(\\mathcal{L}_{\\mathrm{total}}\\) in Eq.(3)." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.465, + 0.208, + 0.481 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.49, + 0.468, + 0.534 + ], + "angle": 0, + "content": "In the following, we conduct experiments to verify the effectiveness and efficiency of the proposed method and analyze the results." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.545, + 0.283, + 0.561 + ], + "angle": 0, + "content": "4.1. Experimental Settings" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.569, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Datasets. Following literature [37, 53, 57, 59, 63, 67], we adopt seven common multi-view datasets in our experiments, including five regular-scale datasets (MNIST-USPS, BDGP, Caltech, COIL-20 and BBCSport) and two largescale datasets (Multi-Fashion and NR-MNIST). MNIST-USPS [53] is a handwritten digital dataset with 5,000 images from 10 categories, where the digits from MNIST and USPS are two views. BDGP [35] includes 2,500 images of Drosophila embryos divided into 5 classes, characterized by visual and textual features. Caltech [16] containing 1,400 RGB images of 7 classes is constructed with 5 different visual descriptors. COIL-20 [59] contains 480 grayscale images of 20 classes, described by 3 different angles. BBCSport [41] is a text dataset in 5 topic areas. It consists of 544 documents collected from the BBC Sport website of sports news articles, related to 2 different viewpoints. Multi-Fashion [66] is also a grayscale image dataset on 10 kinds of 10,000 fashionable products. Three different views are represented by three products from the same category. In terms of NR-MNIST [65], we regard the noise-processed MNIST and the rotated-processed MNIST as two views. We use 60,000 image pairs for the general MVHC" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.092, + 0.89, + 0.121 + ], + "angle": 0, + "content": "experiments in Section 4.2, and use the rest 10,000 image pairs for the inductive HC experiments in Section 4.5." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.123, + 0.892, + 0.365 + ], + "angle": 0, + "content": "Dendrogram Purity measurement for HC. The tree structures with various fine-grained partitional clusters can be truncated at any level. Therefore, instead of using partitional clustering metrics, e.g., ACC and NMI, evaluating the performance of a clustering tree needs a much more comprehensive measurement. To this end, we adopt the Dendrogram Purity (DP) measurement to evaluate the quality of the clustering tree [31, 37, 43], which computes the average purity over the descendant leaves of LCA of all data point pairs belonging to the same ground-truth clusters. Trees with higher DP results tend to be more similar to the ground-truth clusters. Note that the Dasgupta's Cost, another HC metric applied in [5], requires an uncontroversial predefined similarity measurement as input, which is not available in our settings. The detailed reasons for using DP and not using ACC or NMI are given in the appendix." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.365, + 0.892, + 0.501 + ], + "angle": 0, + "content": "Baseline methods. The baselines include three kinds of methods as follows: (1) shallow discrete single-view hierarchical agglomerative clustering methods (HACs), e.g., Single-linkage, Complete-linkage, Average-linkage, and Ward-linkage algorithms; (2) deep continuous single-view HC approaches, e.g., UFit and HypHC, where we concatenate the raw features of all views into a single-view pattern [53]; and (3) State-of-the-art MVHC methods, including MHC and CMHHC." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.501, + 0.892, + 0.698 + ], + "angle": 0, + "content": "Implementation. The proposed network architecture is trained with the PyTorch platform. The fully connected networks with the same architecture are adopted to implement the HAEs for all views in our MHCN. We use the minimal dataset-dependent hyperparameter set for tuning. Since the parameters in hyperbolic space can be considered as Euclidean parameters computed through \\( Z_{\\mathrm{hyp}}^{m} = \\exp_{0}(Z_{\\mathrm{tan}}^{m}) \\), where \\( Z_{\\mathrm{tan}}^{m} \\in \\mathbb{R}^{d} \\), we directly train our model by using the common optimizer Adam. All experiments are conducted on a Linux Server with an Intel Xeon E5-2630 v4 CPU, an NVIDIA TITAN Xp GPU, and 128GB RAM. More implementation details are provided in the supplementary materials." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.711, + 0.804, + 0.727 + ], + "angle": 0, + "content": "4.2. Experimental Results and Analysis" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.892, + 0.901 + ], + "angle": 0, + "content": "The comparison results are shown in Table 1. DP results of the baseline methods on all datasets except NR-MNSIT are directly taken from [37]. We can observe that: (1) MHCN outperforms the second-best baseline, i.e., CMHHC, on all datasets. Unlike two-stage CMHHC, our one-stage framework relieves the separation of multi-view representation learning and hierarchical clustering and naturally makes two associated processes boost each other. (2) Compared with the representative shallow MHC, our deep model also obtains considerable improvements on all datasets. MHC is not capable of learning rich multi-view" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16530" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.093, + 0.089, + 0.881, + 0.271 + ], + "angle": 0, + "content": "
MethodMNIST-USPSBDGPCaltechCOIL-20BBCSportMulti-FashionNR-MNIST
HAC-Single29.81%61.88%23.67%72.56%27.66%27.89%25.77%
HAC-Complete54.36%56.57%30.19%69.95%34.78%48.72%27.71%
HAC-Average69.67%45.91%30.90%73.14%29.05%65.70%59.74%
HAC-Ward80.38%58.61%35.69%80.81%62.65%72.33%76.91%
UFit21.67%69.20%19.00%55.41%30.33%25.94%OOM
HyperHC32.99%31.21%22.46%28.50%29.08%25.65%OOM
MHC78.27%89.14%45.22%66.50%42.43%54.81%40.87%
CMHHC94.49%91.53%66.52%84.89%53.50%96.25%OOM
MHCN99.22%96.22%77.14%94.70%78.93%97.67%98.71%
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.28, + 0.893, + 0.311 + ], + "angle": 0, + "content": "Table 1: Comparison results. Higher DP values indicate better clustering performance. \"OOM\" is out-of-memory on our server." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.324, + 0.896, + 0.441 + ], + "angle": 0, + "content": "
VariantsMNIST-USPSBDGPCaltechCOIL-20BBCSportMulti-FashionNR-MNIST
MHCN (complete)99.22%96.22%77.14%94.70%78.93%97.67%98.71%
w/o Lrc99.07%95.46%*75.17%†93.85%78.38%96.78%*98.20%
w/o Lalign41.29%†56.83%†57.56%†78.68%†40.58%†53.16%†28.36%†
w/o Luni19.42%†44.31%†36.69%†51.57%†28.52%†40.37%†32.64%†
Euclidean AEs92.72%†52.47%†32.50%†70.69%†56.58%†60.55%†53.30%†
" + }, + { + "type": "table_caption", + "bbox": [ + 0.082, + 0.449, + 0.885, + 0.466 + ], + "angle": 0, + "content": "Table 2: Ablation study of our method. “*” and “†” indicate that the difference is significant at 0.05 and 0.01, respectively." + }, + { + "type": "image", + "bbox": [ + 0.12, + 0.478, + 0.363, + 0.556 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.192, + 0.56, + 0.296, + 0.575 + ], + "angle": 0, + "content": "(a) Without \\(\\mathcal{L}_{\\mathrm{uni}}\\)" + }, + { + "type": "image", + "bbox": [ + 0.365, + 0.479, + 0.607, + 0.555 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.434, + 0.559, + 0.553, + 0.575 + ], + "angle": 0, + "content": "(b) With \\(0.1^{*}\\mathcal{L}_{\\mathrm{uni}}\\)" + }, + { + "type": "image", + "bbox": [ + 0.61, + 0.479, + 0.853, + 0.555 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.687, + 0.559, + 0.771, + 0.575 + ], + "angle": 0, + "content": "(c) With \\(\\mathcal{L}_{\\mathrm{uni}}\\)" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.592, + 0.895, + 0.669 + ], + "angle": 0, + "content": "Figure 3: Illustrations of the effectiveness of hyperbolic uniformity learning. We visualize the hyperbolic embeddings and the top-35 non-leaf internal nodes of corresponding decoding dendrograms. Left: Distributions of the learned hyperbolic embeddings optimized by different weights of \\(\\mathcal{L}_{\\mathrm{uni}}\\), i.e., 0.0, 0.1, and 1.0. Right: Top-35 non-leaf internal nodes of corresponding decoding dendrograms. With the weight of \\(\\mathcal{L}_{\\mathrm{uni}}\\) increasing, the distribution becomes uniform and the dendrograms are gradually balanced." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.694, + 0.473, + 0.892 + ], + "angle": 0, + "content": "hierarchical representations as a result of poor hierarchical representation ability and ignorance of the balancing property of the tree structure. (3) Our method performs significantly better than all multi-view concatenation followed by single-view discrete or continuous HC methods. In contrast to concatenating features of all views simply, through learning the multi-view alignment and preserving each view's local relationships, MHCN encodes the meaningful common hierarchical representations across multiple views into the latent hyperbolic space. (4) The performance of MHCN on large-scale NR-MNIST is much better than other comparison methods. Meanwhile, conducting deep methods, like UFit, HyperHC, and CMHHC, on oversized NR-MNSIT re" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.694, + 0.892, + 0.741 + ], + "angle": 0, + "content": "sults in high time complexity and unbearable memory cost. The scalability of MHCN can be attributed to the one-stage pipeline to optimize the total loss by batch-based training." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.754, + 0.666, + 0.769 + ], + "angle": 0, + "content": "4.3. Ablation Studies" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.779, + 0.892, + 0.884 + ], + "angle": 0, + "content": "To further understand the effectiveness of all the factors of MHCN, we conduct ablation studies and report the results in Table 2. We mainly consider the following ablations, i.e., (a) MHCN without \\(\\mathcal{L}_{\\mathrm{rc}}\\), (b) MHCN without \\(\\mathcal{L}_{\\mathrm{align}}\\), (c) MHCN without \\(\\mathcal{L}_{\\mathrm{uni}}\\), and (d) MHCN with Euclidean autoencoders. We also report the significance of test results for the differences compared with MHCN." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.886, + 0.892, + 0.902 + ], + "angle": 0, + "content": "As shown in Table 2, \\(\\mathcal{L}_{\\mathrm{align}}\\) and \\(\\mathcal{L}_{\\mathrm{uni}}\\) both contribute" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "16531" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.165, + 0.089, + 0.805, + 0.135 + ], + "angle": 0, + "content": "
Running TimeMHCNHAC-SingleHAC-CompleteHAC-AverageHAC-Ward
NR-MNIST900.92s1823.43s1903.12s2055.16s2204.11s
" + }, + { + "type": "table_caption", + "bbox": [ + 0.25, + 0.146, + 0.719, + 0.161 + ], + "angle": 0, + "content": "Table 3: Total time spent of MHCN and HACs on NR-MNIST dataset." + }, + { + "type": "image", + "bbox": [ + 0.107, + 0.178, + 0.868, + 0.426 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.075, + 0.438, + 0.892, + 0.5 + ], + "angle": 0, + "content": "Figure 4: The sampled sub-tree of LCA #19978 from the Multi-Fashion HC tree. We can observe that the sub-trees containing more similar kinds of products are closer, e.g., categories Shirt in the green circle and T-Shirt/Top in the blue circle, while less similar products are merged together at higher LCA, e.g., categories Shirt in the green circle and Trouser in the purple circle, or categories Bag in the orange circle and Trouser in the purple circle." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.525, + 0.473, + 0.692 + ], + "angle": 0, + "content": "a lot to the final performance. The effectiveness of \\(\\mathcal{L}_{\\mathrm{rc}}\\) is relatively less significant. This may be due to the property of experimental datasets. Especially, such datasets e.g., MNIST-USPS, Multi-Fashion, and NR-MNSIT are constructed by picking pairs of individual objects from the corresponding classes of multiple datasets [53, 65, 67]. So consistency may play a much more important role compared with complementarity. As for MHCN with Euclidean AEs, we can find that the performance also degenerates significantly, indicating the effectiveness of hyperbolic embeddings for modeling hierarchies." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.704, + 0.47, + 0.9 + ], + "angle": 0, + "content": "In addition, to intuitively show the effectiveness of \\(\\mathcal{L}_{\\mathrm{uni}}\\), taking MNIST-USPS as an example, we train an MHCN model mapping the data to a two-dimensional Poincaré ball with different weights for \\(\\mathcal{L}_{\\mathrm{uni}}\\). We visualize the averaged embeddings and the decoded clustering trees. For clarity, we present the top-35 non-leaf nodes in Figure 3. As shown, if \\(\\mathcal{L}_{\\mathrm{uni}}\\) is absent, only \\(\\mathcal{L}_{\\mathrm{align}}\\) for multi-view consistency and \\(\\mathcal{L}_{\\mathrm{rc}}\\) for multi-view complementarity will force the embeddings to gather in a small corner of the Poincaré ball, resulting in a skewed tree that lacks interpretability. With the weight of \\(\\mathcal{L}_{\\mathrm{uni}}\\) growing, the embeddings become more uniformly distributed, and the corresponding clustering trees become more balanced." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.524, + 0.687, + 0.541 + ], + "angle": 0, + "content": "4.4. Scalability Analysis" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.548, + 0.892, + 0.64 + ], + "angle": 0, + "content": "As shown in Table 1, the DP results of our method exceed those of other baselines on the large-scale NR-MNIST dataset. Also, Table 3 shows that the running time of our method achieves a significant decline when compared with the classic baselines, i.e., HACs. The theoretical complexity analysis can be found in the appendix." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.648, + 0.892, + 0.666 + ], + "angle": 0, + "content": "4.5. Inductive Hierarchical Clustering Experiments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.672, + 0.892, + 0.793 + ], + "angle": 0, + "content": "It is difficult for traditional HAC-based methods to train on one dataset and then predict on another. However, this inductive HC setting becomes relatively easy with MHCN. We train the model with the training set of NR-MNIST, then infer the results with the test set, and finally, the DP result is \\(96.54\\%\\). This result is numerically comparable with the result in Table 1 \\((98.71\\%)\\). The ability of inductive HC may help improve the performance, e.g., transfer learning." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.802, + 0.771, + 0.818 + ], + "angle": 0, + "content": "4.6. Parameter Sensitivity Analysis" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.9 + ], + "angle": 0, + "content": "Trade-off efficient \\(\\alpha\\). To start with, we focus on the choice of the trade-off efficient \\(\\alpha\\). By fixing the other hyperparameters, we investigate how the \\(\\alpha\\) parameter balances the effects of reconstruction and alignment loss components for multi-view learning. We show the DP result of different" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16532" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.09, + 0.465, + 0.246 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.17, + 0.257, + 0.377, + 0.273 + ], + "angle": 0, + "content": "Figure 5: \\(\\alpha\\) sensitivity analysis" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.299, + 0.468, + 0.45 + ], + "angle": 0, + "content": "\\(\\alpha\\) values in a range between 0.0 and 1.0. As shown in Figure 5, with the increase of \\(\\alpha\\) values, the quality of the final tree structures consistently stabilizes at an optimal level on all datasets. When \\(\\alpha = 0\\), the performance of HC gets near the lowest point, especially on MNIST-USPS, BBC-Sport, Multi-Fashion, and NR-MNSIT datasets. The principal reason is that in MHCN, the consistency across all views is achieved via the multi-view alignment loss, which is much essential to capture view-common meaningful semantics and further boost the final clustering trees." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.451, + 0.468, + 0.587 + ], + "angle": 0, + "content": "Temperature parameters \\(\\tau_{\\mathrm{align}}\\) and \\(\\tau_{\\mathrm{uni}}\\). Similarly, with the other hyperparameters fixed, we present the DP results on all datasets by varying \\(\\tau_{\\mathrm{align}}\\) and \\(\\tau_{\\mathrm{uni}}\\) from 0.0 to 5.0. As shown in Figure 6, both \\(\\tau_{\\mathrm{align}}\\) and \\(\\tau_{\\mathrm{uni}}\\) set to around 1.0 achieve optimal performance on MNIST-USPS, BDGP, BBCSport, Multi-Fashion, and NR-MNIST datasets, while the HC performance on Caltech and COIL-20 datasets are more promising with \\(\\tau_{\\mathrm{align}} = \\tau_{\\mathrm{uni}} = 0.5\\). Besides, the model is more robust to changes of \\(\\tau_{\\mathrm{align}}\\)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.596, + 0.2, + 0.612 + ], + "angle": 0, + "content": "4.7. Case Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.62, + 0.468, + 0.816 + ], + "angle": 0, + "content": "In addition to quantitative analysis, we qualitatively examine the quality of the final MVHC tree structures learned by our method. We take a truncated sub-tree of the complete Multi-Fashion tree as an example in Figure 4, where more similar leaf nodes are merged together earlier in the tree structure, guaranteeing explicit hierarchical partitioning. We can observe that more similar leaf nodes are merged together earlier in the tree structure, e.g., categories Shirt and T-Shirt/Top, while less similar products are merged together at higher LCA, e.g., categories Shirt and Trouser, or categories Bag and Trouser. Therefore, MHCN is capable of guaranteeing meaningful fine-grained hierarchical partitioning with high interpretability for the multi-view data." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.83, + 0.331, + 0.846 + ], + "angle": 0, + "content": "5. Conclusion & Future Work" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.468, + 0.901 + ], + "angle": 0, + "content": "In this work, we present a novel one-stage framework MHCN to solve the multi-view hierarchical clustering problem. With the help of the hyperbolic model of the Poincaré" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.101, + 0.697, + 0.163 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.553, + 0.166, + 0.648, + 0.178 + ], + "angle": 0, + "content": "(a) MNIST-USPS" + }, + { + "type": "image", + "bbox": [ + 0.699, + 0.102, + 0.891, + 0.163 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.766, + 0.166, + 0.822, + 0.178 + ], + "angle": 0, + "content": "(b) BDGP" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.192, + 0.699, + 0.253 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.57, + 0.256, + 0.631, + 0.268 + ], + "angle": 0, + "content": "(c) Caltech" + }, + { + "type": "image", + "bbox": [ + 0.701, + 0.192, + 0.892, + 0.253 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.759, + 0.255, + 0.828, + 0.267 + ], + "angle": 0, + "content": "(d) COIL-20" + }, + { + "type": "image", + "bbox": [ + 0.502, + 0.281, + 0.698, + 0.342 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.564, + 0.345, + 0.638, + 0.358 + ], + "angle": 0, + "content": "(e) BBCSport" + }, + { + "type": "image", + "bbox": [ + 0.701, + 0.282, + 0.891, + 0.342 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.747, + 0.345, + 0.84, + 0.357 + ], + "angle": 0, + "content": "(f) Multi-Fashion" + }, + { + "type": "image", + "bbox": [ + 0.599, + 0.371, + 0.795, + 0.432 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.655, + 0.435, + 0.739, + 0.448 + ], + "angle": 0, + "content": "(g) NR-MNIST" + }, + { + "type": "image_caption", + "bbox": [ + 0.551, + 0.46, + 0.841, + 0.476 + ], + "angle": 0, + "content": "Figure 6: \\(\\tau_{\\mathrm{align}}\\) and \\(\\tau_{\\mathrm{uni}}\\) sensitivity analysis" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.504, + 0.892, + 0.761 + ], + "angle": 0, + "content": "ball, we conduct our multi-view representation learning via multiple hyperbolic autoencoders, where the exponential map of each encoder and its inverse logarithm map of each decoder generalize the extracted latent hierarchies to hyperbolic space efficiently. Additionally, we introduce how to promote the final hierarchical clustering tree from the learned hyperbolic representations by jointly optimizing our designed loss functions, including the multi-view alignment loss for view-common information, the reconstruction loss for view-private information, and the hyperbolic uniformity loss for more balanced embedding distribution on the Poincaré ball. Extensive experiments on seven widespread multi-view datasets demonstrate our method achieves state-of-the-art hierarchical clustering performance. In the future, we expect to improve our method with a more general scheme to better learn the different effects of consistency and complementarity of different multi-view datasets." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.778, + 0.659, + 0.795 + ], + "angle": 0, + "content": "Acknowledgments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.803, + 0.892, + 0.901 + ], + "angle": 0, + "content": "This work was partially supported by the National Key Research and Development Program of China (No. 2018AAA0100204), a key program of fundamental research from Shenzhen Science and Technology Innovation Commission (No. JCYJ20200109113403826), the Major Key Project of PCL (No. 2022ZD0115301), and an Open Research Project of Zhejiang Lab (NO.2022RC0AB04)." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "16533" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.079, + 0.09, + 0.176, + 0.107 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.115, + 0.47, + 0.183 + ], + "angle": 0, + "content": "[1] MohammadHossein Bateni, Soheil Behnezhad, Mahsa Derakhshan, MohammadTaghi Hajiaghayi, Raimondas Kiveris, Silvio Lattanzi, and Vahab Mirrokni. Affinity clustering: Hierarchical clustering at scale. In NeurIPS, pages 6864-6874, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.184, + 0.47, + 0.224 + ], + "angle": 0, + "content": "[2] Eugenio Beltrami. Teoria fondamentale degli spazii di curvatura costante. Annali di Matematica Pura ed Applicata (1867-1897), 2(1):232-255, 1868." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.224, + 0.47, + 0.263 + ], + "angle": 0, + "content": "[3] Xiao Cai, Feiping Nie, and Heng Huang. Multi-view k-means clustering on big data. In *IJCAI*, pages 2598-2604, 2013." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.264, + 0.47, + 0.304 + ], + "angle": 0, + "content": "[4] James W Cannon, William J Floyd, Richard Kenyon, Walter R Parry, et al. Hyperbolic geometry. Flavors of geometry, 31(59-115):2, 1997." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.305, + 0.47, + 0.358 + ], + "angle": 0, + "content": "[5] Ines Chami, Albert Gu, Vaggos Chatziafratis, and Christopher Ré. From trees to continuous embeddings and back: Hyperbolic hierarchical clustering. In NeurIPS, pages 15065-15076, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.359, + 0.47, + 0.399 + ], + "angle": 0, + "content": "[6] Ines Chami, Zhitao Ying, Christopher Ré, and Jure Leskovec. Hyperbolic graph convolutional neural networks. In NeurIPS, pages 4869-4880, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.4, + 0.47, + 0.439 + ], + "angle": 0, + "content": "[7] Vaggos Chatziafratis, Rad Niazadeh, and Moses Charikar. Hierarchical clustering with structural constraints. In ICML, pages 774-783. PMLR, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.44, + 0.47, + 0.48 + ], + "angle": 0, + "content": "[8] Kamalika Chaudhuri, Sham M Kakade, Karen Livescu, and Karthik Sridharan. Multi-view clustering via canonical correlation analysis. In ICML, pages 129-136, 2009." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.48, + 0.47, + 0.52 + ], + "angle": 0, + "content": "[9] Giovanni Chierchia and Benjamin Perret. Ultrametric fitting by gradient descent. Journal of Statistical Mechanics: Theory and Experiment, 2020(12):124004, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.521, + 0.47, + 0.574 + ], + "angle": 0, + "content": "[10] Vincent Cohen-Addad, Varun Kanade, Frederik Mallmann-Trenn, and Claire Mathieu. Hierarchical clustering: Objective functions and algorithms. Journal of the ACM (JACM), 66(4):1-42, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.575, + 0.47, + 0.614 + ], + "angle": 0, + "content": "[11] Henry Cohn and Abhinav Kumar. Universally optimal distribution of points on spheres. Journal of the American Mathematical Society, 20(1):99-148, 2007." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.615, + 0.47, + 0.654 + ], + "angle": 0, + "content": "[12] Shuyang Dai, Zhe Gan, Yu Cheng, Chenyang Tao, Lawrence Carin, and Jingjing Liu. Apo-vae: Text generation in hyperbolic space. arXiv preprint arXiv:2005.00054, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.655, + 0.47, + 0.693 + ], + "angle": 0, + "content": "[13] Navneet Dalal and Bill Triggs. Histograms of oriented gradients for human detection. In CVPR, volume 1, pages 886-893. IEEE, 2005." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.694, + 0.47, + 0.722 + ], + "angle": 0, + "content": "[14] Sanjoy Dasgupta. A cost function for similarity-based hierarchical clustering. In STOC, pages 118-127, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.722, + 0.47, + 0.761 + ], + "angle": 0, + "content": "[15] Tim R Davidson, Luca Falorsi, Nicola De Cao, Thomas Kipf, and Jakub M Tomczak. Hyperspherical variational autoencoders. arXiv preprint arXiv:1804.00891, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.761, + 0.47, + 0.802 + ], + "angle": 0, + "content": "[16] Delbert Dueck and Brendan J Frey. Non-metric affinity propagation for unsupervised image categorization. In ICCV, pages 1-8, 2007." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.802, + 0.47, + 0.828 + ], + "angle": 0, + "content": "[17] Joseph Felsenstein and Joseph Felenstein. Inferring phylogenies, volume 2. Sinauer associates Sunderland, MA, 2004." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.829, + 0.47, + 0.882 + ], + "angle": 0, + "content": "[18] Fangxiang Feng, Xiaojie Wang, and Ruifan Li. Cross-modal retrieval with correspondence autoencoder. In Proceedings of the 22nd ACM international conference on Multimedia, pages 7-16, 2014." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.883, + 0.47, + 0.896 + ], + "angle": 0, + "content": "[19] Sylvestre Gallot, Dominique Hulin, and Jacques Lafontaine." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.115, + 0.47, + 0.896 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.094, + 0.829, + 0.106 + ], + "angle": 0, + "content": "Riemannian geometry, volume 2. Springer, 1990." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.107, + 0.891, + 0.133 + ], + "angle": 0, + "content": "[20] Octavian Ganea, Gary Bécigneul, and Thomas Hofmann. Hyperbolic neural networks. In NeurIPS, volume 31, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.133, + 0.892, + 0.172 + ], + "angle": 0, + "content": "[21] Mina GhadimiAtigh, Julian Schoep, Erman Acar, Nanne van Noord, and Pascal Mettes. Hyperbolic image segmentation. arXiv preprint arXiv:2203.05898, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.172, + 0.892, + 0.213 + ], + "angle": 0, + "content": "[22] Zoubin Ghahramani, Michael Jordan, and Ryan P Adams. Tree-structured stick breaking for hierarchical data. In NeurIPS, volume 23, 2010." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.213, + 0.892, + 0.268 + ], + "angle": 0, + "content": "[23] Kamran Ghasedi Dizaji, Amirhossein Herandi, Cheng Deng, Weidong Cai, and Heng Huang. Deep clustering via joint convolutional autoencoder embedding and relative entropy minimization. In ICCV, pages 5736-5745, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.268, + 0.892, + 0.321 + ], + "angle": 0, + "content": "[24] Prasoon Goyal, Zhiting Hu, Xiaodan Liang, Chenyu Wang, and Eric P Xing. Nonparametric variational auto-encoders for hierarchical representation learning. In ICCV, pages 5094–5102, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.322, + 0.892, + 0.348 + ], + "angle": 0, + "content": "[25] Katherine A Heller and Zoubin Ghahramani. Bayesian hierarchical clustering. In ICML, pages 297-304, 2005." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.348, + 0.892, + 0.402 + ], + "angle": 0, + "content": "[26] Joy Hsu, Jeffrey Gu, Gong Wu, Wah Chiu, and Serena Yeung. Capturing implicit hierarchical structure in 3d biomedical images with self-supervised hyperbolic representations. In NeurIPS, pages 5112-5123, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.402, + 0.892, + 0.469 + ], + "angle": 0, + "content": "[27] Shudong Huang, Yixi Liu, Yazhou Ren, Ivor W Tsang, Zenglin Xu, and Jiancheng Lv. Learning smooth representation for multi-view subspace clustering. In Proceedings of the 30th ACM International Conference on Multimedia, pages 3421-3429, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.47, + 0.892, + 0.51 + ], + "angle": 0, + "content": "[28] Anil K Jain, M Narasimha Murty, and Patrick J Flynn. Data clustering: a review. ACM computing surveys (CSUR), 31(3):264-323, 1999." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.51, + 0.892, + 0.55 + ], + "angle": 0, + "content": "[29] Yangbangyan Jiang, Qianqian Xu, Zhiyong Yang, Xiaochun Cao, and Qingming Huang. Dm2c: Deep mixed-modal clustering. In NeurIPS, pages 5880-5890, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.55, + 0.892, + 0.605 + ], + "angle": 0, + "content": "[30] Zhao Kang, Guoxin Shi, Shudong Huang, Wenyu Chen, Xiaorong Pu, Joey Tianyi Zhou, and Zenglin Xu. Multi-graph fusion for multi-view spectral clustering. Knowledge-Based Systems, 189:105102, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.605, + 0.892, + 0.644 + ], + "angle": 0, + "content": "[31] Ari Kobren, Nicholas Monath, Akshay Krishnamurthy, and Andrew McCallum. A hierarchical algorithm for extreme clustering. In KDD, pages 255-264, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.645, + 0.892, + 0.672 + ], + "angle": 0, + "content": "[32] John M Lee. Smooth manifolds. In Introduction to Smooth Manifolds, pages 1-31. Springer, 2013." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.672, + 0.892, + 0.724 + ], + "angle": 0, + "content": "[33] Ruihuang Li, Changqing Zhang, Huazhu Fu, Xi Peng, Tianyi Zhou, and Qinghua Hu. Reciprocal multi-layer subspace learning for multi-view clustering. In ICCV, pages 8172-8180, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.724, + 0.892, + 0.764 + ], + "angle": 0, + "content": "[34] Yingming Li, Ming Yang, and Zhongfei Zhang. A survey of multi-view representation learning. TKDE, 31(10):1863-1883, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.764, + 0.892, + 0.805 + ], + "angle": 0, + "content": "[35] Zhaoyang Li, Qianqian Wang, Zhiqiang Tao, Quanxue Gao, and Zhaohua Yang. Deep adversarial multi-view clustering network. In IJCAI, pages 2952-2958, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.805, + 0.892, + 0.859 + ], + "angle": 0, + "content": "[36] Dongdong Lin, Jigang Zhang, Jingyao Li, Chao Xu, Hong-Wen Deng, and Yu-Ping Wang. An integrative imputation method based on multi-omics datasets. BMC bioinformatics, 17(1):1-12, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.86, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[37] Fangfei Lin, Bing Bai, Kun Bai, Yazhou Ren, Peng Zhao, and Zenglin Xu. Contrastive multi-view hyperbolic hierarchical clustering. In IJCAI, pages 3250-3256, 2022." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.094, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.52, + 0.957 + ], + "angle": 0, + "content": "16534" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[38] Bulou Liu, Bing Bai, Weibang Xie, Yiwen Guo, and Hao Chen. Task-optimized user clustering based on mobile app usage for cold-start recommendations. In KDD, pages 3347–3356, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.147, + 0.469, + 0.201 + ], + "angle": 0, + "content": "[39] Jiyuan Liu, Xinwang Liu, Yuexiang Yang, Li Liu, Siqi Wang, Weixuan Liang, and Jiangyong Shi. One-pass multi-view clustering for large-scale data. In ICCV, pages 12344-12353, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.202, + 0.469, + 0.242 + ], + "angle": 0, + "content": "[40] Weiyang Liu, Rongmei Lin, Zhen Liu, Lixin Liu, Zhiding Yu, Bo Dai, and Le Song. Learning towards minimum hyperspherical energy. In NeurIPS, volume 31, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.242, + 0.469, + 0.282 + ], + "angle": 0, + "content": "[41] Shirui Luo, Changqing Zhang, Wei Zhang, and Xiaochun Cao. Consistent and specific multi-view subspace clustering. In AAAI, pages 3730-3737, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.282, + 0.469, + 0.336 + ], + "angle": 0, + "content": "[42] Emile Mathieu, Charline Le Lan, Chris J Maddison, Ryota Tomioka, and Yee Whye Teh. Continuous hierarchical representations with poincaré variational auto-encoders. In NeurIPS, volume 32, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.336, + 0.469, + 0.39 + ], + "angle": 0, + "content": "[43] Nicholas Monath, Manzil Zaheer, Daniel Silva, Andrew McCallum, and Amr Ahmed. Gradient-based hierarchical clustering using continuous representations of trees in hyperbolic space. In KDD, pages 714-722, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.391, + 0.469, + 0.443 + ], + "angle": 0, + "content": "[44] Fionn Murtagh and Pedro Contreras. Algorithms for hierarchical clustering: an overview. Wiley Interdisciplinary Reviews: Data Mining and Knowledge Discovery, 2(1):86-97, 2012." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.444, + 0.469, + 0.498 + ], + "angle": 0, + "content": "[45] Yoshihiro Nagano, Shoichiro Yamaguchi, Yasuhiro Fujita, and Masanori Koyama. A differentiable gaussian-like distribution on hyperbolic space for gradient-based learning. CoRR, abs/1902.02992, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.499, + 0.469, + 0.539 + ], + "angle": 0, + "content": "[46] Stanislav Naumov, Grigory Yaroslavl'tsev, and Dmitrii Avdiukhin. Objective-based hierarchical clustering of deep embedding vectors. In AAAI, pages 9055-9063, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.539, + 0.469, + 0.579 + ], + "angle": 0, + "content": "[47] Maximillian Nickel and Douwe Kiela. Poincaré embeddings for learning hierarchical representations. In NeurIPS, pages 6338-6347, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.579, + 0.469, + 0.632 + ], + "angle": 0, + "content": "[48] Aude Oliva and Antonio Torralba. Modeling the shape of the scene: A holistic representation of the spatial envelope. International journal of computer vision, 42(3):145-175, 2001." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.633, + 0.469, + 0.659 + ], + "angle": 0, + "content": "[49] Erlin Pan and Zhao Kang. Multi-view contrastive graph clustering. In NeurIPS, volume 34, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.66, + 0.469, + 0.713 + ], + "angle": 0, + "content": "[50] Jiwoong Park, Junho Cho, Hyung Jin Chang, and Jin Young Choi. Unsupervised hyperbolic representation learning via message passing auto-encoders. In CVPR, pages 5516–5526, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.714, + 0.469, + 0.768 + ], + "angle": 0, + "content": "[51] Sakshi Patel, Shivani Sihmar, and Aman Jatain. A study of hierarchical clustering algorithms. In 2015 2nd international conference on computing for sustainable global development (INDIACom), pages 537-541. IEEE, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.768, + 0.469, + 0.809 + ], + "angle": 0, + "content": "[52] Wei Peng, Tuomas Varanka, Abdelrahman Mostafa, Henglin Shi, and Guoying Zhao. Hyperbolic deep neural networks: A survey. arXiv preprint arXiv:2101.04562, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.809, + 0.469, + 0.849 + ], + "angle": 0, + "content": "[53] Xi Peng, Zhenyu Huang, Jiancheng Lv, Hongyuan Zhu, and Joey Tianyi Zhou. Comic: Multi-view clustering without parameter selection. In ICML, pages 5092-5101, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.849, + 0.469, + 0.874 + ], + "angle": 0, + "content": "[54] Peter Petersen. Riemannian geometry, volume 171. Springer, 2006." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.874, + 0.469, + 0.888 + ], + "angle": 0, + "content": "[55] Ryohei Shimizu, Yusuke Mukuta, and Tatsuya Harada." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.888 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "Hyperbolic neural networks++. arXiv preprint arXiv:2006.08210, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.12, + 0.892, + 0.159 + ], + "angle": 0, + "content": "[56] Su-Jin Shin, Kyungwoo Song, and Il-Chul Moon. Hierarchically clustered representation learning. In AAAI, pages 5776-5783, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.16, + 0.892, + 0.213 + ], + "angle": 0, + "content": "[57] Huayi Tang and Yong Liu. Deep safe incomplete multi-view clustering: Theorem and algorithm. In International Conference on Machine Learning, pages 21090-21110. PMLR, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.214, + 0.892, + 0.254 + ], + "angle": 0, + "content": "[58] Yee Teh, Hal Daume III, and Daniel M Roy. Bayesian agglomerative clustering with coalescents. In NeurIPS, volume 20, 2007." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.255, + 0.892, + 0.295 + ], + "angle": 0, + "content": "[59] Daniel J Trosten, Sigurd Lokse, Robert Jenssen, and Michael Kampffmeyer. Reconsidering representation alignment for multi-view clustering. In CVPR, pages 1255-1265, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.295, + 0.892, + 0.334 + ], + "angle": 0, + "content": "[60] Abraham Albert Ungar. A gyrovector space approach to hyperbolic geometry. Synthesis Lectures on Mathematics and Statistics, 1(1):1-194, 2008." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.334, + 0.892, + 0.375 + ], + "angle": 0, + "content": "[61] Dingkang Wang and Yusu Wang. An improved cost function for hierarchical cluster trees. Journal of Computational Geometry, 11(1):283-331, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.375, + 0.892, + 0.416 + ], + "angle": 0, + "content": "[62] Tongzhou Wang and Phillip Isola. Understanding contrastive representation learning through alignment and uniformity on the hypersphere. In ICML, pages 9929-9939. PMLR, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.416, + 0.892, + 0.456 + ], + "angle": 0, + "content": "[63] Weiran Wang, Raman Arora, Karen Livescu, and Jeff Bilmes. On deep multi-view representation learning. In ICML, pages 1083-1092, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.456, + 0.892, + 0.495 + ], + "angle": 0, + "content": "[64] Junyuan Xie, Ross Girshick, and Ali Farhadi. Unsupervised deep embedding for clustering analysis. In ICML, pages 478-487. PMLR, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.495, + 0.892, + 0.549 + ], + "angle": 0, + "content": "[65] Jie Xu, Yazhou Ren, Guofeng Li, Lili Pan, Ce Zhu, and Zenglin Xu. Deep embedded multi-view clustering with collaborative training. Information Sciences, pages 279-290, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.55, + 0.892, + 0.617 + ], + "angle": 0, + "content": "[66] Jie Xu, Yazhou Ren, Huayi Tang, Xiaorong Pu, Xiaofeng Zhu, Ming Zeng, and Lifang He. Multi-vae: Learning disentangled view-common and view-peculiar visual representations for multi-view clustering. In ICCV, pages 9234–9243, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.618, + 0.892, + 0.659 + ], + "angle": 0, + "content": "[67] Jie Xu, Huayi Tang, Yazhou Ren, Liang Peng, Xiaofeng Zhu, and Lifang He. Multi-level feature learning for contrastive multi-view clustering. In CVPR, pages 16051-16060, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.659, + 0.892, + 0.698 + ], + "angle": 0, + "content": "[68] Qinghai Zheng, Jihua Zhu, and Shuangxun Ma. Multi-view hierarchical clustering. arXiv preprint arXiv:2010.07573, 2020." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.698 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16535" + } + ] +] \ No newline at end of file diff --git a/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/803b20b8-8ea9-4642-8b2e-1e4d0ac18614_origin.pdf b/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/803b20b8-8ea9-4642-8b2e-1e4d0ac18614_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..7341b2bc34a191e3f5eac7d0643fcfa88ff98c20 --- /dev/null +++ b/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/803b20b8-8ea9-4642-8b2e-1e4d0ac18614_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:4c72c248266c21bc9028c48b88a1170faa2c28a9a7872a32645cfed2fbf0739b +size 1421452 diff --git a/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/full.md b/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/full.md new file mode 100644 index 0000000000000000000000000000000000000000..8b584c86341ffbf0cb9dece8214ba8ea5f9a6272 --- /dev/null +++ b/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/full.md @@ -0,0 +1,373 @@ +# MHCN: A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering + +Fangfei Lin $^{1,3*}$ , Bing Bai $^{3\dagger}$ , Yiwen Guo $^{6\dagger}$ , Hao Chen $^{4}$ , Yazhou Ren $^{1}$ , Zenglin Xu $^{2,5\dagger}$ $^{1}$ University of Electronic Science and Technology of China, China $^{2}$ Peng Cheng Lab, China + $^{3}$ Tencent Security Big Data Lab, China $^{4}$ University of California, Davis, USA + $^{5}$ Harbin Institute of Technology Shenzhen, China $^{6}$ Independent Researcher + +{phoebe.lin1108,guoyiwen89,zenglin}@gmail.com,icebai@tencent.com + +chen@ucdavis.edu, yazhou. ren@uestc.edu.cn + +# Abstract + +Multi-view hierarchical clustering (MCHC) plays a pivotal role in comprehending the structures within multi-view data, which hinges on the skillful interaction between hierarchical feature learning and comprehensive representation learning across multiple views. However, existing methods often overlook this interplay due to the simple heuristic agglomerative strategies or the decoupling of multi-view representation learning and hierarchical modeling, thus leading to insufficient representation learning. To address these issues, this paper proposes a novel Multi-view Hierarchical Clustering Network (MHCN) model by performing simultaneous multi-view learning and hierarchy modeling. Specifically, to uncover efficient tree-like structures among all views, we derive multiple hyperbolic autoencoders with latent space mapped onto the Poincaré ball. Then, the corresponding hyperbolic embeddings are further regularized to achieve the multi-view representation learning principles for both view-common and view-private information, and to ensure hyperbolic uniformity with a well-balanced hierarchy for better interpretability. Extensive experiments on real-world and synthetic multi-view datasets have demonstrated that our method can achieve state-of-the-art hierarchical clustering performance, and empower the clustering results with good interpretability. + +# 1. Introduction + +Clustering is one of the fundamental research topics in data analysis [28, 44, 51]. With the advances in data acquisition, lots of real-world data could be presented by multiple views, e.g., different visual descriptors like GIST [48] + Histogram of Oriented Gradients (HOG) [13] + other + +![](images/d85cef290d4514cacb305411d2d3bcca58a62eac3b33388f6c6c7f77abdff5b0.jpg) +Figure 1: Comparison between prior MVHC methods, i.e., MHC and CMHHC, versus our proposed MHCN. (a) MHC calculates the average cosine distance matrix of all views and agglomerates the nearest neighbors according to the simply-aligned similarity matrix. (b) CMHHC performs multi-view alignment and similarity learning in the Euclidean space, and hierarchical clustering in hyperbolic space, separately. (c) Our MHCN, a one-stage pipeline, directly aligns the latent hierarchies on different Poincaré balls, leading to more effective MVHC trees. + +deep features [53] for an image. Multiple views contain both congruent and incongruent information, which can be leveraged to explore potential consistency and complementarity across views and provide more comprehensive latent representations to facilitate downstream tasks, especially for unsupervised learning. This leads to the prevalence of multi-view clustering including multi-view partitional clustering [29, 35, 39, 49, 59] and multi-view hierarchical clustering [37, 68]. Aiming for high interpretability, multi-view hierarchical clustering is particularly appealing in the analysis of multi-view data at various levels of gran + +ularity. For instance, gene expression analysis [36] integrates multi-omics data and clusters cells into an organization/organ/system hierarchy. Besides, species trees [17], gathering animals by their physical appearances, sounds, or other features, reflect the hierarchical organization in phylogenetic inference. + +Despite these merits, there are still significant limitations in existing multi-view hierarchical clustering methods. As shown in Figure 1, existing models for solving the MVHC problem include the discrete linkage-based method Multiview Hierarchical Clustering (MHC) [68], and the continuous deep neural network-based Contrastive Multi-view Hyperbolic Hierarchical Clustering (CMHHC) [37]. As a seminal work for MVHC, shallow MHC partitions multi-view data at multiple levels through the cosine distance integration and the nearest neighbor agglomeration components. However, without applying deep representation learning, this method simply considers the mean latent feature vectors as the common representations of all views. Thus, it cannot fully capture the consistency and complementarity among different views, leading to degenerated HC performance, especially on complicated real-world datasets. The two-stage deep model CMHHC integrates a multi-view alignment learning module, an aligned feature similarity learning module, and a continuous hyperbolic hierarchical clustering module. However, CMHHC takes into account two independent geometry settings, treating multiview learning in the Euclidean space and HC in hyperbolic space, enlarging the gap between the two processes. Thus, the performance may still be suboptimal. + +To address these issues, this paper proposes the Multi-view Hierarchical Clustering Network (MHCN), as sketched in Figure 2. Taking the desired MVHC tree structures into consideration, we make corresponding designs for MHCN as follows. Firstly, drawing inspiration from the recent success of latent hyperbolic anatomy [42, 52], which excels in modeling hierarchies with minimal distortion, we incorporate multiple hyperbolic autoencoders to capture the inherent hierarchies present in different views. Secondly, considering multi-view consistent and complementary principles [34, 66], we design the multi-view alignment loss between two arbitrary views to discover the view-common information, and use the reconstruction loss to retain the view-private information, respectively. Thirdly, uniformly-distributed hyperbolic embeddings on the Poincaré ball create well-balanced trees, leading to more interpretable semantics compared with skewed ones. In order to improve interpretability in clustering trees, we encourage the balanced hierarchy construction via a hyperbolic uniformity loss, which facilitates learning such hyperbolic embeddings. In this way, MHCN provides explicit guidance for ensuring the quality of the tree structure and integrates multi-view representation learning and hierarchy discovery + +processes on hyperbolic manifolds with hierarchy-friendly hyperbolic autoencoders. As the pioneering one-stage solution for the MVHC problem, the MHCN model collectively optimizes the three objectives with mini-batch training. Thus, large datasets can be efficiently processed. After obtaining the optimal hyperbolic hierarchical representations for unseen data with trained neural networks, MHCN can decode back to the underlying tree structures, making inductive hierarchical clustering possible. + +Different from existing MVHC models, our contributions are summarized as follows. + +- We analyze the multi-view hierarchical clustering problem and propose a novel hyperbolic neural network-based model to tackle the problem, where the latent space is grafted on the Poincaré ball of hyperbolic space for explicit hierarchical structures. +- We introduce three objectives to facilitate the final multi-view hierarchical clustering trees with desired properties, i.e., a multi-view alignment loss, a reconstruction loss, and a hyperbolic uniformity loss. +- We conduct extensive experiments to show the superiority of MHCN compared with other multi-view HC methods in terms of both effectiveness and scalability. + +# 2. Related Work + +# 2.1. Hierarchical Clustering + +Bottom-up linkage algorithms for solving HC are simple and easy to implement, which recursively merge similar data points to build larger cluster sub-trees until a complete dendrogram appears [10, 31]. Typical agglomerative heuristics include Single Linkage, Complete Linkage, Average Linkage, and Ward Linkage [10]. While these traditional algorithms are widely used in practice, there is a limit to fit continuous optimization due to their inherent discreteness [14, 43, 61]. Hence, there have been more attempts at gradient-based HC through embedding methods recently [5, 9, 24, 46, 56]. For example, UFit [9] proposed a gradient-based fitting framework over ultrametric. Besides, similarity-based HypHC [5] directly relaxed Dasgupta's cost with the aid of the continuous form of hyperbolic leaf nodes and lowest common ancestors (LCAs). + +In contrast to the above HC methods, our unified framework is multi-view data-oriented, which can be optimized continuously via specifically-designed hierarchical clustering objectives. Also, little previous research pays close attention to the balancing property of clustering trees, which is one of the mainly-addressed spots in our method. + +# 2.2. Multi-view Clustering + +Existing multi-view clustering (MVC) methods can be roughly classified into four categories, namely, canon- + +![](images/2c883b2229c78c6a7083be34be73dea6f6ee16d84c01a9ef262cc3556f8719b8.jpg) +Figure 2: Overview of the proposed MHCN (taking two views as an example). MHCN assigns a hyperbolic autoencoder to each view, with the latent space grafted on the Poincaré ball for explicit hierarchies, where the exponential mapping function $\exp_0$ follows the hyperbolic encoder, and the hyperbolic decoder connects behind the logarithm mapping function $\log_0$ . The whole model is trained with the three joint learning objectives: (1) the multi-view alignment learning aims to align the hyperbolic embeddings $z_i^1$ and $z_i^2$ , (2) the reconstruction for HAE is used to project the complementary information in each view into the latent space, and (3) the hyperbolic uniformity learning guarantees $z_i^1$ and $z_i^2$ to distribute uniformly on the corresponding Poincaré balls, respectively. After $\beta$ -fusion, the final MVHC tree can be decoded from the common hyperbolic representations. + +ical correlation analysis-based [8], matrix factorization-based [3], subspace-based [27, 33] and graph-based [30] methods. Recently, deep MVC methods have been developed increasingly [35, 38, 49, 53, 59, 67]. However, most methods are limited to partitional clustering. The high computational complexities of these methods hinder the practicability and development of multi-view hierarchical clustering. To this end, research about MVHC has gradually emerged. Shallow MHC [68] roughly averages the cosine distance graphs for common latent features, which cannot achieve consistency of all views. A recent two-stage deep method CMHHC [37] presents an MVHC tree over aligned common representations through three modules, i.e., multiview alignment learning, unsupervised metric learning, and hyperbolic hierarchical clustering. + +Unlike CMHHC, which regards multi-view representation learning and hierarchical clustering as two separate stages, our method unifies them into a one-stage training pipeline, where they can reinforce each other for naturally contributing to the final HC trees. + +# 2.3. Hyperbolic Models + +There is extensive literature on hierarchical models conducted in the Euclidean space and its applications [22, 25, 58]. However, suffering from the inherent discrete na + +ture of trees, the Euclidean hierarchical models have difficulty in constructing the hierarchical structure of data explicitly, while hyperbolic models can. The underlying reason is that the exponential growth of the volume in hyperbolic space with its radius is analogous to the exponential growth of the number of leaves in a tree with its altitude, which is infeasible in the Euclidean space [43]. Thus, there has been an increasing interest in the generalization of hyperbolic neural networks to learn hyperbolic representations [6, 20, 26, 42, 50, 55]. + +# 3. Method + +In this part, we propose a hyperbolic neural network model for MVHC, termed as Multi-view Hierarchical Clustering Network (MHCN), as shown in Figure 2. For clarity, we first briefly review the background of hyperbolic geometry and a specific hyperbolic model, i.e., the Poincaré ball. Then, we describe the architecture of HAE, define what desired trees look like through specific loss functions, and introduce the decoding strategy. Lastly, we summarize the whole optimization process. + +Let $\{\pmb{X}^m\in \mathbb{R}^{N\times D_m}\}_{m = 1}^M$ be a multi-view dataset including $N$ samples across $M$ views, where each $\pmb{x}_i^m\in \mathbb{R}^{D_m}$ denotes the $i$ -th instance of $D_{m}$ dimension from the $m$ -th view. Our target is to present a unified method for + +clustering tree learning by searching over multi-view continuous hierarchical representations in hyperbolic space. + +# 3.1. Preliminaries + +We first introduce the Riemannian geometry and the Poincaré ball model of hyperbolic geometry, with which we build the hyperbolic autoencoders for our model. A more detailed review can be found in the appendix. + +# 3.1.1 Riemannian Geometry + +An $n$ -dimensional manifold $\mathcal{M}$ [19, 54] is a real and smooth space, which can be locally approximated to a linear $n$ -dimensional space $\mathbb{R}^n$ at each point $\pmb{x} \in \mathcal{M}$ . For any point $\pmb{x}$ of the manifold $\mathcal{M}$ , the corresponding local tangent space $\mathcal{T}_x\mathcal{M}$ , is the first order linear approximation of $\mathcal{M}$ around the point $\pmb{x}$ . The related metric tensor $g_x: \mathcal{T}_x\mathcal{M} \times \mathcal{T}_x\mathcal{M} \to \mathbb{R}$ defines an inner product on $\mathcal{T}_x\mathcal{M}$ and a Riemannian metric $g = (g_x)_{x \in \mathcal{M}}$ is a set of such inner products on $\mathcal{M}$ . In this way, a Riemannian manifold can be presented as a matching tuple $(\mathcal{M}, g)$ . With $g_x$ , the local geometric attributions of $\mathcal{T}_x\mathcal{M}$ are accessible, and then the global distances can be achieved by integrating the local properties together. To project a tangent vector $z$ in $\mathcal{T}_x\mathcal{M}$ onto $\mathcal{M}$ along a geodesic with constant velocity, the exponential map $\exp_x: \mathcal{T}_x\mathcal{M} \to \mathcal{M}$ is given, and the inverse form is logarithmic map $\log_x: \mathcal{M} \to \mathcal{T}_x\mathcal{M}$ [20, 52, 55]. More detailed review is in the appendix. + +# 3.1.2 Poincaré Ball Model of Hyperbolic Geometry + +Many studies [12, 21, 47] have demonstrated that data representations in most machine learning applications lie on a Riemannian manifold [32]. Later on, how to generalize neural networks to a Riemannian space has made remarkable progress [15, 42, 45]. An $n$ -dimensional hyperbolic space $\mathbb{H}^n$ is an $n$ -dimensional Riemannian manifold with constant negative curvature [2, 4]. We choose to perform our model on the $n$ -dimensional Poincaré ball $(\mathbb{B}^n,g^{\mathbb{B}})$ with a constant negative curvature $-1$ , where $\mathbb{B}^n = \{\pmb {x}\in \mathbb{R}^n:||\pmb {x}||^2 < 1\}$ is an open ball of curvature $-1$ , and its hyperbolic metric tensor $g_{\pmb{x}}^{\mathbb{B}} = \lambda_{\pmb{x}}^{2}g^{E}$ is conformal to the Euclidean one. $\lambda_{\pmb{x}}^{2} = \frac{2}{1 - ||\pmb{x}||^{2}}$ is a conformal factor, and $g^{E} = I_{n}$ denotes the dot product in the Euclidean space. + +Given $z, z' \in \mathbb{B}^n$ and $t \in \mathcal{T}_z\mathbb{B}^n$ , the exponential map $\exp_z: \mathcal{T}_z\mathbb{B}^n \to \mathbb{B}^n$ and the logarithm map $\log_z: \mathbb{B}^n \to \mathcal{T}_z\mathbb{B}^n$ realize the projection from the Euclidean space onto the Poincaré ball and vice versa, respectively. To enable the mathematical operations for hyperbolic space models, the framework of gyrovector spaces provides the algebraic setting for the hyperbolic geometry. With the Möbius Addition $\oplus$ [60], the closed-form expressions of + +$\exp_z$ and $\log_z$ are respectively given by + +$$ +\exp_ {z} (\boldsymbol {t}) = \boldsymbol {z} \oplus \left(\tanh \left(\frac {\lambda_ {z} \| \boldsymbol {t} \|}{2}\right) \frac {\boldsymbol {t}}{\| \boldsymbol {t} \|}\right), \tag {1} +$$ + +$$ +\log_ {z} (z ^ {\prime}) = \frac {2}{\lambda_ {z}} \mathrm {a r c t a n h} (| | - z \oplus z ^ {\prime} | |) \frac {- z \oplus z ^ {\prime}}{| | - z \oplus z ^ {\prime} | |}. +$$ + +For the convenience in practice, $z$ is usually set to the origin $\mathbf{0}$ , so the $\exp_z$ and $\log_z$ can be simplified as + +$$ +\exp_ {\mathbf {0}} (\boldsymbol {t}) = \tanh (| | \boldsymbol {t} | |) \frac {\boldsymbol {t}}{| | \boldsymbol {t} | |}), \tag {2} +$$ + +$$ +\log_ {\mathbf {0}} \left(\boldsymbol {z} ^ {\prime}\right) = \operatorname {a r c t a n h} \left(\left| \left| \boldsymbol {z} ^ {\prime} \right| \right|\right) \frac {\boldsymbol {z} ^ {\prime}}{\left| \left| \boldsymbol {z} ^ {\prime} \right| \right|}. +$$ + +By means of the above main operations $\exp_0(t)$ and $\log_0(z')$ , MHCN is able to perform the basic transformations of the latent representations between the Euclidean space and the hyperbolic space. + +# 3.2. Hyperbolic Autoencoders + +The conventional approach to learning useful representations is through a regular Euclidean autoencoder [18, 23, 64]. However, there has been significant interest in hierarchical representation learning using non-Euclidean geometry, specifically the hyperbolic space. This attention arises from the fact that the number of leaf nodes in tree structures increases exponentially with depth, mirroring the exponential growth of the hyperbolic surface area with its radius, while the growth in the Euclidean space is polynomial [6, 20, 52, 55]. As a result, we augment the standard autoencoder with hyperbolic geometry in the embedding space, and propose a novel multi-view hyperbolic model consisting of multiple hyperbolic autoencoders assigned for different views, shown in Figure 2. Each hyperbolic autoencoder's geometry-aware encoder and decoder are constructed via the introduced exponential and logarithmic map functions in Eq.(2). We show the detailed structures of the encoders and the decoders in the following. + +# 3.2.1 Encoder with the Exponential Map + +With regard to the $m$ -th view $\pmb{X}^{m}$ , the encoder of $m$ -th HAE, i.e., $f_{\mathrm{enc}}(\pmb{X}^{m};\theta_{\mathrm{enc}}^{m}): \pmb{X}^{m} \in \mathbb{R}^{D_{m}} \to \pmb{Z}_{\mathrm{hyp}}^{m} \in \mathbb{B}^{d}$ , is designed as a regular Euclidean encoder followed by the exponential map $\exp_0(\cdot)$ , along with which the output of the hyperbolic encoder is projected onto the Poincaré ball. $\pmb{Z}_{\mathrm{hyp}}^{m}$ represents the $d$ -dimensional hyperbolic latent code with explicit hierarchical patterns and $\theta_{\mathrm{enc}}^{m}$ denotes the encoder parameters. + +# 3.2.2 Decoder with the Logarithm Map + +Similar to the hyperbolic encoder, the decoder of the $m$ -th HAE, $f_{\mathrm{dec}}(\pmb{X}^m;\theta_{\mathrm{dec}}^m): \pmb{Z}_{\mathrm{hyp}}^m \in \mathbb{B}^d \to \pmb{X}^m \in \mathbb{R}^{D_m}$ + +for the $m$ -th view $\mathbf{X}^m$ which is parameterized by $\theta_{\mathrm{dec}}^m$ , is constituted of a regular Euclidean decoder preprocessed by the logarithm map $\log_0(\cdot)$ , projecting the latent hyperbolic features back to the Euclidean space. + +# 3.3. Loss Functions for Desired HC Trees + +High-quality MVHC trees should: 1) preserve the intrinsic hierarchy of each view via learned hyperbolic embeddings, 2) make full use of multi-view complementary and consistent information to acquire common hierarchical representations, and 3) not increase hierarchies without strong necessity [1, 7, 14, 62]. In this section, based on the structure of multi-view HAEs, we design the total loss functions for our model to realize the above characteristics: + +$$ +\mathcal {L} _ {\text {t o t a l}} = \mathcal {L} _ {\mathrm {m v l}} + \mathcal {L} _ {\mathrm {u n i}}. \tag {3} +$$ + +In our model, we jointly achieve the multi-view consistency and complementarity in the hyperbolic common-view space by optimizing the combined loss $\mathcal{L}_{\mathrm{mvl}}$ of the multi-view alignment loss $\mathcal{L}_{\mathrm{align}}$ and the reconstruction loss $\mathcal{L}_{\mathrm{rc}}$ : + +$$ +\mathcal {L} _ {\mathrm {m v l}} = \alpha \mathcal {L} _ {\text {a l i g n}} + (1 - \alpha) \mathcal {L} _ {\mathrm {r c}}, \tag {4} +$$ + +where $\alpha$ is a trade-off coefficient to balance the effects of consistency and complementarity for multi-view learning. + +Learning view-common consistency with the multi-view alignment loss. The extracted common representations $\{Z_{\mathrm{hyp}}^m = f_{\mathrm{enc}}(X^m)\}_{m=1}^M$ are expected not only to uncover the complementary relationships among different views but also to contain sufficient consensus information of all views. To achieve consistency across multiple views, we apply distance and similarity-based alignment by conducting a multi-view alignment loss endowed on the hyperbolic embeddings. Here, we consider the cosine distance between two latent features $z_i^{m_1}$ and $z_j^{m_2}$ as the similarity measurement for multi-view alignment: + +$$ +\sin \left(\boldsymbol {z} _ {i} ^ {m _ {1}}, \boldsymbol {z} _ {i} ^ {m _ {2}}\right) = \frac {\left\langle \boldsymbol {z} _ {i} ^ {m _ {1}} , \boldsymbol {z} _ {j} ^ {m _ {2}} \right\rangle}{\left| \left| \boldsymbol {z} _ {i} ^ {m _ {1}} \right| \right| \left| \left| \boldsymbol {z} _ {j} ^ {m _ {2}} \right| \right|}. \tag {5} +$$ + +Supported by the conformality property of the Riemannian geometry, i.e., the Poincaré ball preserves the same angels as the Euclidean space, the computation of the cosine similarity in the Euclidean space is equal to that on the Poincaré ball [20, 55]. Besides, unlike the geodesic distances, values of the cosine distances are kept in a certain range, which is friendly to optimization processes. + +Then, the multi-view alignment loss between the hyperbolic embeddings of the same instance from any two views $Z_{\mathrm{hyp}}^{m_1}, Z_{\mathrm{hyp}}^{m_2}$ is given by: + +$$ +\mathcal {L} _ {\text {a l i g n}} ^ {(m _ {1}, m _ {2})} = - \frac {1}{N} \sum_ {i = 1} ^ {N} \sin \left(\boldsymbol {z} _ {i} ^ {m _ {1}}, \boldsymbol {z} _ {i} ^ {m _ {2}}\right) / \tau_ {\text {a l i g n}}, \tag {6} +$$ + +where $\tau_{\mathrm{align}}$ is used as a temperature parameter for the scaled distance function. Here, we notice that CMHHC [37] also serves to learn common representations. However, CMHHC aligns Euclidean features, while MHCN directly makes the corresponding hyperbolic embeddings closer. + +Therefore, the complete multi-view alignment loss across all view pairs is formulated as: + +$$ +\mathcal {L} _ {\text {a l i g n}} = \sum_ {m _ {1} = 1} ^ {M} \sum_ {m _ {2} = 1, m _ {1} \neq m _ {2}} ^ {M} \mathcal {L} _ {\text {a l i g n}} ^ {(m _ {1}, m _ {2})}. \tag {7} +$$ + +Learning view-private complementarity with the reconstruction loss of HAEs. In multi-view representation learning models, autoencoders are widely used for their impressive strengths, such as preserving the useful view-private information and preventing data points from collapsing to a small number of clusters [29, 67]. In our multi-view hierarchical clustering model, the learned representations by multiple HAEs consider the preservation of the local hierarchical structure within each view. This implies that similar instances from each view remain close to each other in the hyperbolic space, while the latent codes obtained from dissimilar instances remain distant from one another. To this end, the total reconstruction loss function of HAEs for multiple views is formulated as + +$$ +\mathcal {L} _ {\mathrm {r c}} = \sum_ {m = 1} ^ {M} \mathcal {L} _ {\mathrm {r c}} ^ {m} = \sum_ {m = 1} ^ {M} \frac {1}{N} \sum_ {i = 1} ^ {N} \left| \left| \boldsymbol {x} _ {i} ^ {m} - f _ {\mathrm {d e c}} \left(f _ {\mathrm {e n c}} \left(\boldsymbol {x} _ {i} ^ {m}\right)\right) \right| \right| _ {2} ^ {2}, \tag {8} +$$ + +where $\mathcal{L}_{\mathrm{rc}}^m$ is the corresponding $m$ -th view objective to reconstruct $\pmb{X}^{m}$ . + +Learning tree balancing property with the hyperbolic uniformity loss. Through the multi-view alignment and reconstruction related to the Poincaré ball, our model obtains reliable multi-view representations and discovers the hierarchical structure of each view simultaneously. Last but not least, a hierarchical clustering tree with explicit balancing property provides fewer hierarchies and higher interpretability than skewed ones. + +Consequently, we leverage the uniformity of the hyperbolic embedding distribution located on the Poincaré ball to learn separable features and enhance the contribution of the balanced affinity. Concretely, considering the form of Gaussian potential kernel [11, 40], we define a hyperbolic uniformity objective based on the cosine distance as: + +$$ +\mathcal {L} _ {\mathrm {u n i}} = \sum_ {m = 1} ^ {M} \frac {1}{N ^ {2}} \sum_ {i = 1} ^ {N} \sum_ {j = 1} ^ {N} \log \left(e ^ {- t \left(- \operatorname {s i m} \left(\boldsymbol {z} _ {i} ^ {m}, \boldsymbol {z} _ {j} ^ {m}\right) / \tau_ {\mathrm {u n i}}\right)}\right). \tag {9} +$$ + +Still, the temperature parameter $\tau_{\mathrm{uni}}$ is a scaling factor to the cosine distance. Intuitively, the hyperbolic uniformity loss encourages the latent hyperbolic embeddings to push farther away from each other and to benefit the uniform global distribution of embeddings on the Poincaré ball. + +# 3.4. From Hyperbolic Embeddings to Binary Trees + +We first adopt $\beta$ -fusion [55] to concatenate the optimal hyperbolic embeddings from multiple views into the common-view space, to guarantee the concatenated norms maintain upper-bounded by the radius of the Poincaré ball. To output an intuitive HC tree from the common continuous hyperbolic representations on the Poincaré ball back to discrete HC trees with low error, we apply the decoding strategy proposed by [5], which realizes the underlying correspondence between the hyperbolic embeddings and the HC trees with low-error. This bottom-up decoding algorithm decodes the common hyperbolic embeddings by measuring the similarity of any two embeddings with the distance from their lowest common ancient (LCA) to the origin of the ball and merging more similar ones iteratively. + +# 3.5. Optimization Process + +The whole optimization process of MHCN is summarized in the appendix. We train this model by adopting a one-stage pipeline of mini-batch gradient descent, making our method feasible to scale up to large-scale scenarios. Concretely, the integrated framework of multiple HAEs is optimized collectively with the $\mathcal{L}_{\mathrm{total}}$ in Eq.(3). + +# 4. Experiments + +In the following, we conduct experiments to verify the effectiveness and efficiency of the proposed method and analyze the results. + +# 4.1. Experimental Settings + +Datasets. Following literature [37, 53, 57, 59, 63, 67], we adopt seven common multi-view datasets in our experiments, including five regular-scale datasets (MNIST-USPS, BDGP, Caltech, COIL-20 and BBCSport) and two largescale datasets (Multi-Fashion and NR-MNIST). MNIST-USPS [53] is a handwritten digital dataset with 5,000 images from 10 categories, where the digits from MNIST and USPS are two views. BDGP [35] includes 2,500 images of Drosophila embryos divided into 5 classes, characterized by visual and textual features. Caltech [16] containing 1,400 RGB images of 7 classes is constructed with 5 different visual descriptors. COIL-20 [59] contains 480 grayscale images of 20 classes, described by 3 different angles. BBCSport [41] is a text dataset in 5 topic areas. It consists of 544 documents collected from the BBC Sport website of sports news articles, related to 2 different viewpoints. Multi-Fashion [66] is also a grayscale image dataset on 10 kinds of 10,000 fashionable products. Three different views are represented by three products from the same category. In terms of NR-MNIST [65], we regard the noise-processed MNIST and the rotated-processed MNIST as two views. We use 60,000 image pairs for the general MVHC + +experiments in Section 4.2, and use the rest 10,000 image pairs for the inductive HC experiments in Section 4.5. + +Dendrogram Purity measurement for HC. The tree structures with various fine-grained partitional clusters can be truncated at any level. Therefore, instead of using partitional clustering metrics, e.g., ACC and NMI, evaluating the performance of a clustering tree needs a much more comprehensive measurement. To this end, we adopt the Dendrogram Purity (DP) measurement to evaluate the quality of the clustering tree [31, 37, 43], which computes the average purity over the descendant leaves of LCA of all data point pairs belonging to the same ground-truth clusters. Trees with higher DP results tend to be more similar to the ground-truth clusters. Note that the Dasgupta's Cost, another HC metric applied in [5], requires an uncontroversial predefined similarity measurement as input, which is not available in our settings. The detailed reasons for using DP and not using ACC or NMI are given in the appendix. + +Baseline methods. The baselines include three kinds of methods as follows: (1) shallow discrete single-view hierarchical agglomerative clustering methods (HACs), e.g., Single-linkage, Complete-linkage, Average-linkage, and Ward-linkage algorithms; (2) deep continuous single-view HC approaches, e.g., UFit and HypHC, where we concatenate the raw features of all views into a single-view pattern [53]; and (3) State-of-the-art MVHC methods, including MHC and CMHHC. + +Implementation. The proposed network architecture is trained with the PyTorch platform. The fully connected networks with the same architecture are adopted to implement the HAEs for all views in our MHCN. We use the minimal dataset-dependent hyperparameter set for tuning. Since the parameters in hyperbolic space can be considered as Euclidean parameters computed through $Z_{\mathrm{hyp}}^{m} = \exp_{0}(Z_{\mathrm{tan}}^{m})$ , where $Z_{\mathrm{tan}}^{m} \in \mathbb{R}^{d}$ , we directly train our model by using the common optimizer Adam. All experiments are conducted on a Linux Server with an Intel Xeon E5-2630 v4 CPU, an NVIDIA TITAN Xp GPU, and 128GB RAM. More implementation details are provided in the supplementary materials. + +# 4.2. Experimental Results and Analysis + +The comparison results are shown in Table 1. DP results of the baseline methods on all datasets except NR-MNSIT are directly taken from [37]. We can observe that: (1) MHCN outperforms the second-best baseline, i.e., CMHHC, on all datasets. Unlike two-stage CMHHC, our one-stage framework relieves the separation of multi-view representation learning and hierarchical clustering and naturally makes two associated processes boost each other. (2) Compared with the representative shallow MHC, our deep model also obtains considerable improvements on all datasets. MHC is not capable of learning rich multi-view + +
MethodMNIST-USPSBDGPCaltechCOIL-20BBCSportMulti-FashionNR-MNIST
HAC-Single29.81%61.88%23.67%72.56%27.66%27.89%25.77%
HAC-Complete54.36%56.57%30.19%69.95%34.78%48.72%27.71%
HAC-Average69.67%45.91%30.90%73.14%29.05%65.70%59.74%
HAC-Ward80.38%58.61%35.69%80.81%62.65%72.33%76.91%
UFit21.67%69.20%19.00%55.41%30.33%25.94%OOM
HyperHC32.99%31.21%22.46%28.50%29.08%25.65%OOM
MHC78.27%89.14%45.22%66.50%42.43%54.81%40.87%
CMHHC94.49%91.53%66.52%84.89%53.50%96.25%OOM
MHCN99.22%96.22%77.14%94.70%78.93%97.67%98.71%
+ +Table 1: Comparison results. Higher DP values indicate better clustering performance. "OOM" is out-of-memory on our server. + +
VariantsMNIST-USPSBDGPCaltechCOIL-20BBCSportMulti-FashionNR-MNIST
MHCN (complete)99.22%96.22%77.14%94.70%78.93%97.67%98.71%
w/o Lrc99.07%95.46%*75.17%†93.85%78.38%96.78%*98.20%
w/o Lalign41.29%†56.83%†57.56%†78.68%†40.58%†53.16%†28.36%†
w/o Luni19.42%†44.31%†36.69%†51.57%†28.52%†40.37%†32.64%†
Euclidean AEs92.72%†52.47%†32.50%†70.69%†56.58%†60.55%†53.30%†
+ +Table 2: Ablation study of our method. “*” and “†” indicate that the difference is significant at 0.05 and 0.01, respectively. + +![](images/9de1e42d495922a07a145a1bc5acc790a597ef9e5dcfde08944732ba83e07a6c.jpg) +(a) Without $\mathcal{L}_{\mathrm{uni}}$ + +![](images/2fabbc73164c0d5e7916e0a295df27126b751d119ffa43827afa14e8c87b85f1.jpg) +(b) With $0.1^{*}\mathcal{L}_{\mathrm{uni}}$ +Figure 3: Illustrations of the effectiveness of hyperbolic uniformity learning. We visualize the hyperbolic embeddings and the top-35 non-leaf internal nodes of corresponding decoding dendrograms. Left: Distributions of the learned hyperbolic embeddings optimized by different weights of $\mathcal{L}_{\mathrm{uni}}$ , i.e., 0.0, 0.1, and 1.0. Right: Top-35 non-leaf internal nodes of corresponding decoding dendrograms. With the weight of $\mathcal{L}_{\mathrm{uni}}$ increasing, the distribution becomes uniform and the dendrograms are gradually balanced. + +![](images/0b77a8ddc5e55d3021a913016d9bfe2ec6f19276cbf84e1bc2d7b38036d463d3.jpg) +(c) With $\mathcal{L}_{\mathrm{uni}}$ + +hierarchical representations as a result of poor hierarchical representation ability and ignorance of the balancing property of the tree structure. (3) Our method performs significantly better than all multi-view concatenation followed by single-view discrete or continuous HC methods. In contrast to concatenating features of all views simply, through learning the multi-view alignment and preserving each view's local relationships, MHCN encodes the meaningful common hierarchical representations across multiple views into the latent hyperbolic space. (4) The performance of MHCN on large-scale NR-MNIST is much better than other comparison methods. Meanwhile, conducting deep methods, like UFit, HyperHC, and CMHHC, on oversized NR-MNSIT re + +sults in high time complexity and unbearable memory cost. The scalability of MHCN can be attributed to the one-stage pipeline to optimize the total loss by batch-based training. + +# 4.3. Ablation Studies + +To further understand the effectiveness of all the factors of MHCN, we conduct ablation studies and report the results in Table 2. We mainly consider the following ablations, i.e., (a) MHCN without $\mathcal{L}_{\mathrm{rc}}$ , (b) MHCN without $\mathcal{L}_{\mathrm{align}}$ , (c) MHCN without $\mathcal{L}_{\mathrm{uni}}$ , and (d) MHCN with Euclidean autoencoders. We also report the significance of test results for the differences compared with MHCN. + +As shown in Table 2, $\mathcal{L}_{\mathrm{align}}$ and $\mathcal{L}_{\mathrm{uni}}$ both contribute + +
Running TimeMHCNHAC-SingleHAC-CompleteHAC-AverageHAC-Ward
NR-MNIST900.92s1823.43s1903.12s2055.16s2204.11s
+ +Table 3: Total time spent of MHCN and HACs on NR-MNIST dataset. + +![](images/015c2a6544b227a6320fdffb513628017b043051a68ede74ad2df42045831a56.jpg) +Figure 4: The sampled sub-tree of LCA #19978 from the Multi-Fashion HC tree. We can observe that the sub-trees containing more similar kinds of products are closer, e.g., categories Shirt in the green circle and T-Shirt/Top in the blue circle, while less similar products are merged together at higher LCA, e.g., categories Shirt in the green circle and Trouser in the purple circle, or categories Bag in the orange circle and Trouser in the purple circle. + +a lot to the final performance. The effectiveness of $\mathcal{L}_{\mathrm{rc}}$ is relatively less significant. This may be due to the property of experimental datasets. Especially, such datasets e.g., MNIST-USPS, Multi-Fashion, and NR-MNSIT are constructed by picking pairs of individual objects from the corresponding classes of multiple datasets [53, 65, 67]. So consistency may play a much more important role compared with complementarity. As for MHCN with Euclidean AEs, we can find that the performance also degenerates significantly, indicating the effectiveness of hyperbolic embeddings for modeling hierarchies. + +In addition, to intuitively show the effectiveness of $\mathcal{L}_{\mathrm{uni}}$ , taking MNIST-USPS as an example, we train an MHCN model mapping the data to a two-dimensional Poincaré ball with different weights for $\mathcal{L}_{\mathrm{uni}}$ . We visualize the averaged embeddings and the decoded clustering trees. For clarity, we present the top-35 non-leaf nodes in Figure 3. As shown, if $\mathcal{L}_{\mathrm{uni}}$ is absent, only $\mathcal{L}_{\mathrm{align}}$ for multi-view consistency and $\mathcal{L}_{\mathrm{rc}}$ for multi-view complementarity will force the embeddings to gather in a small corner of the Poincaré ball, resulting in a skewed tree that lacks interpretability. With the weight of $\mathcal{L}_{\mathrm{uni}}$ growing, the embeddings become more uniformly distributed, and the corresponding clustering trees become more balanced. + +# 4.4. Scalability Analysis + +As shown in Table 1, the DP results of our method exceed those of other baselines on the large-scale NR-MNIST dataset. Also, Table 3 shows that the running time of our method achieves a significant decline when compared with the classic baselines, i.e., HACs. The theoretical complexity analysis can be found in the appendix. + +# 4.5. Inductive Hierarchical Clustering Experiments + +It is difficult for traditional HAC-based methods to train on one dataset and then predict on another. However, this inductive HC setting becomes relatively easy with MHCN. We train the model with the training set of NR-MNIST, then infer the results with the test set, and finally, the DP result is $96.54\%$ . This result is numerically comparable with the result in Table 1 $(98.71\%)$ . The ability of inductive HC may help improve the performance, e.g., transfer learning. + +# 4.6. Parameter Sensitivity Analysis + +Trade-off efficient $\alpha$ . To start with, we focus on the choice of the trade-off efficient $\alpha$ . By fixing the other hyperparameters, we investigate how the $\alpha$ parameter balances the effects of reconstruction and alignment loss components for multi-view learning. We show the DP result of different + +![](images/f8448c59cbb99f670b254d45d552b1bb5b6ba2c93750cd75d7651e35ec40eb86.jpg) +Figure 5: $\alpha$ sensitivity analysis + +$\alpha$ values in a range between 0.0 and 1.0. As shown in Figure 5, with the increase of $\alpha$ values, the quality of the final tree structures consistently stabilizes at an optimal level on all datasets. When $\alpha = 0$ , the performance of HC gets near the lowest point, especially on MNIST-USPS, BBC-Sport, Multi-Fashion, and NR-MNSIT datasets. The principal reason is that in MHCN, the consistency across all views is achieved via the multi-view alignment loss, which is much essential to capture view-common meaningful semantics and further boost the final clustering trees. + +Temperature parameters $\tau_{\mathrm{align}}$ and $\tau_{\mathrm{uni}}$ . Similarly, with the other hyperparameters fixed, we present the DP results on all datasets by varying $\tau_{\mathrm{align}}$ and $\tau_{\mathrm{uni}}$ from 0.0 to 5.0. As shown in Figure 6, both $\tau_{\mathrm{align}}$ and $\tau_{\mathrm{uni}}$ set to around 1.0 achieve optimal performance on MNIST-USPS, BDGP, BBCSport, Multi-Fashion, and NR-MNIST datasets, while the HC performance on Caltech and COIL-20 datasets are more promising with $\tau_{\mathrm{align}} = \tau_{\mathrm{uni}} = 0.5$ . Besides, the model is more robust to changes of $\tau_{\mathrm{align}}$ . + +# 4.7. Case Study + +In addition to quantitative analysis, we qualitatively examine the quality of the final MVHC tree structures learned by our method. We take a truncated sub-tree of the complete Multi-Fashion tree as an example in Figure 4, where more similar leaf nodes are merged together earlier in the tree structure, guaranteeing explicit hierarchical partitioning. We can observe that more similar leaf nodes are merged together earlier in the tree structure, e.g., categories Shirt and T-Shirt/Top, while less similar products are merged together at higher LCA, e.g., categories Shirt and Trouser, or categories Bag and Trouser. Therefore, MHCN is capable of guaranteeing meaningful fine-grained hierarchical partitioning with high interpretability for the multi-view data. + +# 5. Conclusion & Future Work + +In this work, we present a novel one-stage framework MHCN to solve the multi-view hierarchical clustering problem. With the help of the hyperbolic model of the Poincaré + +![](images/2227b53728230b7cf32a6901b571a50b52889213861a2ffffbf4fd30a52d6231.jpg) +(a) MNIST-USPS + +![](images/230f3dad9f90ed092e7cf5cc83fe5c5bac6b27bc1a088341e5002f9342e2ac67.jpg) +(b) BDGP + +![](images/ceda2cd50902ef1edc37a3444bedfdd9608e1777df74820a9e1c1401bc5cd7b6.jpg) +(c) Caltech + +![](images/14c79c7887b8928bc55546b9a46c9d9ec100cc04af2d239bd65faba546f9ef7a.jpg) +(d) COIL-20 + +![](images/620ee05bb04673a7ebed7083552168fa3d90c503462abd264c41302b90b1f7ff.jpg) +(e) BBCSport + +![](images/7d03a7770de56127019df89a871dddda191749c90cc50fcbd32d919190dc7e2e.jpg) +(f) Multi-Fashion + +![](images/37d1ae9f38436c608d377fa1c78d2a750c3c332108af97b89e02ce9907bf536b.jpg) +(g) NR-MNIST +Figure 6: $\tau_{\mathrm{align}}$ and $\tau_{\mathrm{uni}}$ sensitivity analysis + +ball, we conduct our multi-view representation learning via multiple hyperbolic autoencoders, where the exponential map of each encoder and its inverse logarithm map of each decoder generalize the extracted latent hierarchies to hyperbolic space efficiently. Additionally, we introduce how to promote the final hierarchical clustering tree from the learned hyperbolic representations by jointly optimizing our designed loss functions, including the multi-view alignment loss for view-common information, the reconstruction loss for view-private information, and the hyperbolic uniformity loss for more balanced embedding distribution on the Poincaré ball. Extensive experiments on seven widespread multi-view datasets demonstrate our method achieves state-of-the-art hierarchical clustering performance. In the future, we expect to improve our method with a more general scheme to better learn the different effects of consistency and complementarity of different multi-view datasets. + +# Acknowledgments + +This work was partially supported by the National Key Research and Development Program of China (No. 2018AAA0100204), a key program of fundamental research from Shenzhen Science and Technology Innovation Commission (No. JCYJ20200109113403826), the Major Key Project of PCL (No. 2022ZD0115301), and an Open Research Project of Zhejiang Lab (NO.2022RC0AB04). + +# References + +[1] MohammadHossein Bateni, Soheil Behnezhad, Mahsa Derakhshan, MohammadTaghi Hajiaghayi, Raimondas Kiveris, Silvio Lattanzi, and Vahab Mirrokni. Affinity clustering: Hierarchical clustering at scale. In NeurIPS, pages 6864-6874, 2017. +[2] Eugenio Beltrami. Teoria fondamentale degli spazii di curvatura costante. Annali di Matematica Pura ed Applicata (1867-1897), 2(1):232-255, 1868. +[3] Xiao Cai, Feiping Nie, and Heng Huang. Multi-view k-means clustering on big data. In *IJCAI*, pages 2598-2604, 2013. +[4] James W Cannon, William J Floyd, Richard Kenyon, Walter R Parry, et al. Hyperbolic geometry. Flavors of geometry, 31(59-115):2, 1997. +[5] Ines Chami, Albert Gu, Vaggos Chatziafratis, and Christopher Ré. From trees to continuous embeddings and back: Hyperbolic hierarchical clustering. In NeurIPS, pages 15065-15076, 2020. +[6] Ines Chami, Zhitao Ying, Christopher Ré, and Jure Leskovec. Hyperbolic graph convolutional neural networks. In NeurIPS, pages 4869-4880, 2019. +[7] Vaggos Chatziafratis, Rad Niazadeh, and Moses Charikar. Hierarchical clustering with structural constraints. In ICML, pages 774-783. PMLR, 2018. +[8] Kamalika Chaudhuri, Sham M Kakade, Karen Livescu, and Karthik Sridharan. Multi-view clustering via canonical correlation analysis. In ICML, pages 129-136, 2009. +[9] Giovanni Chierchia and Benjamin Perret. Ultrametric fitting by gradient descent. Journal of Statistical Mechanics: Theory and Experiment, 2020(12):124004, 2020. +[10] Vincent Cohen-Addad, Varun Kanade, Frederik Mallmann-Trenn, and Claire Mathieu. Hierarchical clustering: Objective functions and algorithms. Journal of the ACM (JACM), 66(4):1-42, 2019. +[11] Henry Cohn and Abhinav Kumar. Universally optimal distribution of points on spheres. Journal of the American Mathematical Society, 20(1):99-148, 2007. +[12] Shuyang Dai, Zhe Gan, Yu Cheng, Chenyang Tao, Lawrence Carin, and Jingjing Liu. Apo-vae: Text generation in hyperbolic space. arXiv preprint arXiv:2005.00054, 2020. +[13] Navneet Dalal and Bill Triggs. Histograms of oriented gradients for human detection. In CVPR, volume 1, pages 886-893. IEEE, 2005. +[14] Sanjoy Dasgupta. A cost function for similarity-based hierarchical clustering. In STOC, pages 118-127, 2016. +[15] Tim R Davidson, Luca Falorsi, Nicola De Cao, Thomas Kipf, and Jakub M Tomczak. Hyperspherical variational autoencoders. arXiv preprint arXiv:1804.00891, 2018. +[16] Delbert Dueck and Brendan J Frey. Non-metric affinity propagation for unsupervised image categorization. In ICCV, pages 1-8, 2007. +[17] Joseph Felsenstein and Joseph Felenstein. Inferring phylogenies, volume 2. Sinauer associates Sunderland, MA, 2004. +[18] Fangxiang Feng, Xiaojie Wang, and Ruifan Li. Cross-modal retrieval with correspondence autoencoder. In Proceedings of the 22nd ACM international conference on Multimedia, pages 7-16, 2014. +[19] Sylvestre Gallot, Dominique Hulin, and Jacques Lafontaine. + +Riemannian geometry, volume 2. Springer, 1990. +[20] Octavian Ganea, Gary Bécigneul, and Thomas Hofmann. Hyperbolic neural networks. In NeurIPS, volume 31, 2018. +[21] Mina GhadimiAtigh, Julian Schoep, Erman Acar, Nanne van Noord, and Pascal Mettes. Hyperbolic image segmentation. arXiv preprint arXiv:2203.05898, 2022. +[22] Zoubin Ghahramani, Michael Jordan, and Ryan P Adams. Tree-structured stick breaking for hierarchical data. In NeurIPS, volume 23, 2010. +[23] Kamran Ghasedi Dizaji, Amirhossein Herandi, Cheng Deng, Weidong Cai, and Heng Huang. Deep clustering via joint convolutional autoencoder embedding and relative entropy minimization. In ICCV, pages 5736-5745, 2017. +[24] Prasoon Goyal, Zhiting Hu, Xiaodan Liang, Chenyu Wang, and Eric P Xing. Nonparametric variational auto-encoders for hierarchical representation learning. In ICCV, pages 5094–5102, 2017. +[25] Katherine A Heller and Zoubin Ghahramani. Bayesian hierarchical clustering. In ICML, pages 297-304, 2005. +[26] Joy Hsu, Jeffrey Gu, Gong Wu, Wah Chiu, and Serena Yeung. Capturing implicit hierarchical structure in 3d biomedical images with self-supervised hyperbolic representations. In NeurIPS, pages 5112-5123, 2021. +[27] Shudong Huang, Yixi Liu, Yazhou Ren, Ivor W Tsang, Zenglin Xu, and Jiancheng Lv. Learning smooth representation for multi-view subspace clustering. In Proceedings of the 30th ACM International Conference on Multimedia, pages 3421-3429, 2022. +[28] Anil K Jain, M Narasimha Murty, and Patrick J Flynn. Data clustering: a review. ACM computing surveys (CSUR), 31(3):264-323, 1999. +[29] Yangbangyan Jiang, Qianqian Xu, Zhiyong Yang, Xiaochun Cao, and Qingming Huang. Dm2c: Deep mixed-modal clustering. In NeurIPS, pages 5880-5890, 2019. +[30] Zhao Kang, Guoxin Shi, Shudong Huang, Wenyu Chen, Xiaorong Pu, Joey Tianyi Zhou, and Zenglin Xu. Multi-graph fusion for multi-view spectral clustering. Knowledge-Based Systems, 189:105102, 2020. +[31] Ari Kobren, Nicholas Monath, Akshay Krishnamurthy, and Andrew McCallum. A hierarchical algorithm for extreme clustering. In KDD, pages 255-264, 2017. +[32] John M Lee. Smooth manifolds. In Introduction to Smooth Manifolds, pages 1-31. Springer, 2013. +[33] Ruihuang Li, Changqing Zhang, Huazhu Fu, Xi Peng, Tianyi Zhou, and Qinghua Hu. Reciprocal multi-layer subspace learning for multi-view clustering. In ICCV, pages 8172-8180, 2019. +[34] Yingming Li, Ming Yang, and Zhongfei Zhang. A survey of multi-view representation learning. TKDE, 31(10):1863-1883, 2018. +[35] Zhaoyang Li, Qianqian Wang, Zhiqiang Tao, Quanxue Gao, and Zhaohua Yang. Deep adversarial multi-view clustering network. In IJCAI, pages 2952-2958, 2019. +[36] Dongdong Lin, Jigang Zhang, Jingyao Li, Chao Xu, Hong-Wen Deng, and Yu-Ping Wang. An integrative imputation method based on multi-omics datasets. BMC bioinformatics, 17(1):1-12, 2016. +[37] Fangfei Lin, Bing Bai, Kun Bai, Yazhou Ren, Peng Zhao, and Zenglin Xu. Contrastive multi-view hyperbolic hierarchical clustering. In IJCAI, pages 3250-3256, 2022. + +[38] Bulou Liu, Bing Bai, Weibang Xie, Yiwen Guo, and Hao Chen. Task-optimized user clustering based on mobile app usage for cold-start recommendations. In KDD, pages 3347–3356, 2022. +[39] Jiyuan Liu, Xinwang Liu, Yuexiang Yang, Li Liu, Siqi Wang, Weixuan Liang, and Jiangyong Shi. One-pass multi-view clustering for large-scale data. In ICCV, pages 12344-12353, 2021. +[40] Weiyang Liu, Rongmei Lin, Zhen Liu, Lixin Liu, Zhiding Yu, Bo Dai, and Le Song. Learning towards minimum hyperspherical energy. In NeurIPS, volume 31, 2018. +[41] Shirui Luo, Changqing Zhang, Wei Zhang, and Xiaochun Cao. Consistent and specific multi-view subspace clustering. In AAAI, pages 3730-3737, 2018. +[42] Emile Mathieu, Charline Le Lan, Chris J Maddison, Ryota Tomioka, and Yee Whye Teh. Continuous hierarchical representations with poincaré variational auto-encoders. In NeurIPS, volume 32, 2019. +[43] Nicholas Monath, Manzil Zaheer, Daniel Silva, Andrew McCallum, and Amr Ahmed. Gradient-based hierarchical clustering using continuous representations of trees in hyperbolic space. In KDD, pages 714-722, 2019. +[44] Fionn Murtagh and Pedro Contreras. Algorithms for hierarchical clustering: an overview. Wiley Interdisciplinary Reviews: Data Mining and Knowledge Discovery, 2(1):86-97, 2012. +[45] Yoshihiro Nagano, Shoichiro Yamaguchi, Yasuhiro Fujita, and Masanori Koyama. A differentiable gaussian-like distribution on hyperbolic space for gradient-based learning. CoRR, abs/1902.02992, 2019. +[46] Stanislav Naumov, Grigory Yaroslavl'tsev, and Dmitrii Avdiukhin. Objective-based hierarchical clustering of deep embedding vectors. In AAAI, pages 9055-9063, 2021. +[47] Maximillian Nickel and Douwe Kiela. Poincaré embeddings for learning hierarchical representations. In NeurIPS, pages 6338-6347, 2017. +[48] Aude Oliva and Antonio Torralba. Modeling the shape of the scene: A holistic representation of the spatial envelope. International journal of computer vision, 42(3):145-175, 2001. +[49] Erlin Pan and Zhao Kang. Multi-view contrastive graph clustering. In NeurIPS, volume 34, 2021. +[50] Jiwoong Park, Junho Cho, Hyung Jin Chang, and Jin Young Choi. Unsupervised hyperbolic representation learning via message passing auto-encoders. In CVPR, pages 5516–5526, 2021. +[51] Sakshi Patel, Shivani Sihmar, and Aman Jatain. A study of hierarchical clustering algorithms. In 2015 2nd international conference on computing for sustainable global development (INDIACom), pages 537-541. IEEE, 2015. +[52] Wei Peng, Tuomas Varanka, Abdelrahman Mostafa, Henglin Shi, and Guoying Zhao. Hyperbolic deep neural networks: A survey. arXiv preprint arXiv:2101.04562, 2021. +[53] Xi Peng, Zhenyu Huang, Jiancheng Lv, Hongyuan Zhu, and Joey Tianyi Zhou. Comic: Multi-view clustering without parameter selection. In ICML, pages 5092-5101, 2019. +[54] Peter Petersen. Riemannian geometry, volume 171. Springer, 2006. +[55] Ryohei Shimizu, Yusuke Mukuta, and Tatsuya Harada. + +Hyperbolic neural networks++. arXiv preprint arXiv:2006.08210, 2020. +[56] Su-Jin Shin, Kyungwoo Song, and Il-Chul Moon. Hierarchically clustered representation learning. In AAAI, pages 5776-5783, 2020. +[57] Huayi Tang and Yong Liu. Deep safe incomplete multi-view clustering: Theorem and algorithm. In International Conference on Machine Learning, pages 21090-21110. PMLR, 2022. +[58] Yee Teh, Hal Daume III, and Daniel M Roy. Bayesian agglomerative clustering with coalescents. In NeurIPS, volume 20, 2007. +[59] Daniel J Trosten, Sigurd Lokse, Robert Jenssen, and Michael Kampffmeyer. Reconsidering representation alignment for multi-view clustering. In CVPR, pages 1255-1265, 2021. +[60] Abraham Albert Ungar. A gyrovector space approach to hyperbolic geometry. Synthesis Lectures on Mathematics and Statistics, 1(1):1-194, 2008. +[61] Dingkang Wang and Yusu Wang. An improved cost function for hierarchical cluster trees. Journal of Computational Geometry, 11(1):283-331, 2020. +[62] Tongzhou Wang and Phillip Isola. Understanding contrastive representation learning through alignment and uniformity on the hypersphere. In ICML, pages 9929-9939. PMLR, 2020. +[63] Weiran Wang, Raman Arora, Karen Livescu, and Jeff Bilmes. On deep multi-view representation learning. In ICML, pages 1083-1092, 2015. +[64] Junyuan Xie, Ross Girshick, and Ali Farhadi. Unsupervised deep embedding for clustering analysis. In ICML, pages 478-487. PMLR, 2016. +[65] Jie Xu, Yazhou Ren, Guofeng Li, Lili Pan, Ce Zhu, and Zenglin Xu. Deep embedded multi-view clustering with collaborative training. Information Sciences, pages 279-290, 2021. +[66] Jie Xu, Yazhou Ren, Huayi Tang, Xiaorong Pu, Xiaofeng Zhu, Ming Zeng, and Lifang He. Multi-vae: Learning disentangled view-common and view-peculiar visual representations for multi-view clustering. In ICCV, pages 9234–9243, 2021. +[67] Jie Xu, Huayi Tang, Yazhou Ren, Liang Peng, Xiaofeng Zhu, and Lifang He. Multi-level feature learning for contrastive multi-view clustering. In CVPR, pages 16051-16060, 2022. +[68] Qinghai Zheng, Jihua Zhu, and Shuangxun Ma. Multi-view hierarchical clustering. arXiv preprint arXiv:2010.07573, 2020. \ No newline at end of file diff --git a/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/images.zip b/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..5d7b3be3a39a003ba11e4915b0ce80b5b65dbb81 --- /dev/null +++ b/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:d0eb091e5ee45f894936667d3705120ebc0272911743f73d691e6c169536cd18 +size 587715 diff --git a/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/layout.json b/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..6353460d17750d3df145bb84d16e8a0c1aaaacf2 --- /dev/null +++ b/2023/MHCN_ A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering/layout.json @@ -0,0 +1,10781 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 154, + 103, + 440, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 154, + 103, + 440, + 140 + ], + "spans": [ + { + "bbox": [ + 154, + 103, + 440, + 140 + ], + "type": "text", + "content": "MHCN: A Hyperbolic Neural Network Model for Multi-view Hierarchical Clustering" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "spans": [ + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "content": "Fangfei Lin" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "inline_equation", + "content": "^{1,3*}" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "content": ", Bing Bai" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "inline_equation", + "content": "^{3\\dagger}" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "content": ", Yiwen Guo" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "inline_equation", + "content": "^{6\\dagger}" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "content": ", Hao Chen" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "content": ", Yazhou Ren" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "content": ", Zenglin Xu" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "inline_equation", + "content": "^{2,5\\dagger}" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "content": "University of Electronic Science and Technology of China, China " + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "content": "Peng Cheng Lab, China \n" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "content": "Tencent Security Big Data Lab, China " + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "content": "University of California, Davis, USA \n" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "inline_equation", + "content": "^{5}" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "content": "Harbin Institute of Technology Shenzhen, China " + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "inline_equation", + "content": "^{6}" + }, + { + "bbox": [ + 70, + 160, + 523, + 217 + ], + "type": "text", + "content": "Independent Researcher" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 123, + 219, + 470, + 232 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 123, + 219, + 470, + 232 + ], + "spans": [ + { + "bbox": [ + 123, + 219, + 470, + 232 + ], + "type": "text", + "content": "{phoebe.lin1108,guoyiwen89,zenglin}@gmail.com,icebai@tencent.com" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 187, + 234, + 405, + 244 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 187, + 234, + 405, + 244 + ], + "spans": [ + { + "bbox": [ + 187, + 234, + 405, + 244 + ], + "type": "text", + "content": "chen@ucdavis.edu, yazhou. ren@uestc.edu.cn" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 143, + 273, + 192, + 285 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 273, + 192, + 285 + ], + "spans": [ + { + "bbox": [ + 143, + 273, + 192, + 285 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 298, + 290, + 586 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 298, + 290, + 586 + ], + "spans": [ + { + "bbox": [ + 46, + 298, + 290, + 586 + ], + "type": "text", + "content": "Multi-view hierarchical clustering (MCHC) plays a pivotal role in comprehending the structures within multi-view data, which hinges on the skillful interaction between hierarchical feature learning and comprehensive representation learning across multiple views. However, existing methods often overlook this interplay due to the simple heuristic agglomerative strategies or the decoupling of multi-view representation learning and hierarchical modeling, thus leading to insufficient representation learning. To address these issues, this paper proposes a novel Multi-view Hierarchical Clustering Network (MHCN) model by performing simultaneous multi-view learning and hierarchy modeling. Specifically, to uncover efficient tree-like structures among all views, we derive multiple hyperbolic autoencoders with latent space mapped onto the Poincaré ball. Then, the corresponding hyperbolic embeddings are further regularized to achieve the multi-view representation learning principles for both view-common and view-private information, and to ensure hyperbolic uniformity with a well-balanced hierarchy for better interpretability. Extensive experiments on real-world and synthetic multi-view datasets have demonstrated that our method can achieve state-of-the-art hierarchical clustering performance, and empower the clustering results with good interpretability." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 606, + 128, + 619 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 606, + 128, + 619 + ], + "spans": [ + { + "bbox": [ + 47, + 606, + 128, + 619 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 626, + 287, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 626, + 287, + 687 + ], + "spans": [ + { + "bbox": [ + 46, + 626, + 287, + 687 + ], + "type": "text", + "content": "Clustering is one of the fundamental research topics in data analysis [28, 44, 51]. With the advances in data acquisition, lots of real-world data could be presented by multiple views, e.g., different visual descriptors like GIST [48] + Histogram of Oriented Gradients (HOG) [13] + other" + } + ] + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 307, + 271, + 545, + 423 + ], + "blocks": [ + { + "bbox": [ + 307, + 271, + 545, + 423 + ], + "lines": [ + { + "bbox": [ + 307, + 271, + 545, + 423 + ], + "spans": [ + { + "bbox": [ + 307, + 271, + 545, + 423 + ], + "type": "image", + "image_path": "d85cef290d4514cacb305411d2d3bcca58a62eac3b33388f6c6c7f77abdff5b0.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 430, + 547, + 552 + ], + "lines": [ + { + "bbox": [ + 304, + 430, + 547, + 552 + ], + "spans": [ + { + "bbox": [ + 304, + 430, + 547, + 552 + ], + "type": "text", + "content": "Figure 1: Comparison between prior MVHC methods, i.e., MHC and CMHHC, versus our proposed MHCN. (a) MHC calculates the average cosine distance matrix of all views and agglomerates the nearest neighbors according to the simply-aligned similarity matrix. (b) CMHHC performs multi-view alignment and similarity learning in the Euclidean space, and hierarchical clustering in hyperbolic space, separately. (c) Our MHCN, a one-stage pipeline, directly aligns the latent hierarchies on different Poincaré balls, leading to more effective MVHC trees." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "type": "text", + "content": "deep features [53] for an image. Multiple views contain both congruent and incongruent information, which can be leveraged to explore potential consistency and complementarity across views and provide more comprehensive latent representations to facilitate downstream tasks, especially for unsupervised learning. This leads to the prevalence of multi-view clustering including multi-view partitional clustering [29, 35, 39, 49, 59] and multi-view hierarchical clustering [37, 68]. Aiming for high interpretability, multi-view hierarchical clustering is particularly appealing in the analysis of multi-view data at various levels of gran" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 693, + 269, + 703 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 693, + 269, + 703 + ], + "spans": [ + { + "bbox": [ + 58, + 693, + 269, + 703 + ], + "type": "text", + "content": "*This work was done when Fangfei Lin was an intern at Tencent." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "type": "text", + "content": "† Corresponding authors." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16525" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 288, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 288, + 144 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 288, + 144 + ], + "type": "text", + "content": "ularity. For instance, gene expression analysis [36] integrates multi-omics data and clusters cells into an organization/organ/system hierarchy. Besides, species trees [17], gathering animals by their physical appearances, sounds, or other features, reflect the hierarchical organization in phylogenetic inference." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 148, + 288, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 148, + 288, + 434 + ], + "spans": [ + { + "bbox": [ + 46, + 148, + 288, + 434 + ], + "type": "text", + "content": "Despite these merits, there are still significant limitations in existing multi-view hierarchical clustering methods. As shown in Figure 1, existing models for solving the MVHC problem include the discrete linkage-based method Multiview Hierarchical Clustering (MHC) [68], and the continuous deep neural network-based Contrastive Multi-view Hyperbolic Hierarchical Clustering (CMHHC) [37]. As a seminal work for MVHC, shallow MHC partitions multi-view data at multiple levels through the cosine distance integration and the nearest neighbor agglomeration components. However, without applying deep representation learning, this method simply considers the mean latent feature vectors as the common representations of all views. Thus, it cannot fully capture the consistency and complementarity among different views, leading to degenerated HC performance, especially on complicated real-world datasets. The two-stage deep model CMHHC integrates a multi-view alignment learning module, an aligned feature similarity learning module, and a continuous hyperbolic hierarchical clustering module. However, CMHHC takes into account two independent geometry settings, treating multiview learning in the Euclidean space and HC in hyperbolic space, enlarging the gap between the two processes. Thus, the performance may still be suboptimal." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "text", + "content": "To address these issues, this paper proposes the Multi-view Hierarchical Clustering Network (MHCN), as sketched in Figure 2. Taking the desired MVHC tree structures into consideration, we make corresponding designs for MHCN as follows. Firstly, drawing inspiration from the recent success of latent hyperbolic anatomy [42, 52], which excels in modeling hierarchies with minimal distortion, we incorporate multiple hyperbolic autoencoders to capture the inherent hierarchies present in different views. Secondly, considering multi-view consistent and complementary principles [34, 66], we design the multi-view alignment loss between two arbitrary views to discover the view-common information, and use the reconstruction loss to retain the view-private information, respectively. Thirdly, uniformly-distributed hyperbolic embeddings on the Poincaré ball create well-balanced trees, leading to more interpretable semantics compared with skewed ones. In order to improve interpretability in clustering trees, we encourage the balanced hierarchy construction via a hyperbolic uniformity loss, which facilitates learning such hyperbolic embeddings. In this way, MHCN provides explicit guidance for ensuring the quality of the tree structure and integrates multi-view representation learning and hierarchy discovery" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 304, + 72, + 545, + 179 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 179 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 179 + ], + "type": "text", + "content": "processes on hyperbolic manifolds with hierarchy-friendly hyperbolic autoencoders. As the pioneering one-stage solution for the MVHC problem, the MHCN model collectively optimizes the three objectives with mini-batch training. Thus, large datasets can be efficiently processed. After obtaining the optimal hyperbolic hierarchical representations for unseen data with trained neural networks, MHCN can decode back to the underlying tree structures, making inductive hierarchical clustering possible." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 305, + 180, + 545, + 203 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 180, + 545, + 203 + ], + "spans": [ + { + "bbox": [ + 305, + 180, + 545, + 203 + ], + "type": "text", + "content": "Different from existing MVHC models, our contributions are summarized as follows." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 317, + 208, + 545, + 363 + ], + "type": "list", + "angle": 0, + "index": 8, + "blocks": [ + { + "bbox": [ + 317, + 208, + 545, + 267 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 208, + 545, + 267 + ], + "spans": [ + { + "bbox": [ + 317, + 208, + 545, + 267 + ], + "type": "text", + "content": "- We analyze the multi-view hierarchical clustering problem and propose a novel hyperbolic neural network-based model to tackle the problem, where the latent space is grafted on the Poincaré ball of hyperbolic space for explicit hierarchical structures." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 317, + 274, + 545, + 322 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 274, + 545, + 322 + ], + "spans": [ + { + "bbox": [ + 317, + 274, + 545, + 322 + ], + "type": "text", + "content": "- We introduce three objectives to facilitate the final multi-view hierarchical clustering trees with desired properties, i.e., a multi-view alignment loss, a reconstruction loss, and a hyperbolic uniformity loss." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 328, + 545, + 363 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 328, + 545, + 363 + ], + "spans": [ + { + "bbox": [ + 317, + 328, + 545, + 363 + ], + "type": "text", + "content": "- We conduct extensive experiments to show the superiority of MHCN compared with other multi-view HC methods in terms of both effectiveness and scalability." + } + ] + } + ], + "index": 7 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 376, + 392, + 388 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 376, + 392, + 388 + ], + "spans": [ + { + "bbox": [ + 306, + 376, + 392, + 388 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 396, + 440, + 408 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 396, + 440, + 408 + ], + "spans": [ + { + "bbox": [ + 306, + 396, + 440, + 408 + ], + "type": "text", + "content": "2.1. Hierarchical Clustering" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 415, + 545, + 593 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 415, + 545, + 593 + ], + "spans": [ + { + "bbox": [ + 304, + 415, + 545, + 593 + ], + "type": "text", + "content": "Bottom-up linkage algorithms for solving HC are simple and easy to implement, which recursively merge similar data points to build larger cluster sub-trees until a complete dendrogram appears [10, 31]. Typical agglomerative heuristics include Single Linkage, Complete Linkage, Average Linkage, and Ward Linkage [10]. While these traditional algorithms are widely used in practice, there is a limit to fit continuous optimization due to their inherent discreteness [14, 43, 61]. Hence, there have been more attempts at gradient-based HC through embedding methods recently [5, 9, 24, 46, 56]. For example, UFit [9] proposed a gradient-based fitting framework over ultrametric. Besides, similarity-based HypHC [5] directly relaxed Dasgupta's cost with the aid of the continuous form of hyperbolic leaf nodes and lowest common ancestors (LCAs)." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 594, + 545, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 545, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 545, + 665 + ], + "type": "text", + "content": "In contrast to the above HC methods, our unified framework is multi-view data-oriented, which can be optimized continuously via specifically-designed hierarchical clustering objectives. Also, little previous research pays close attention to the balancing property of clustering trees, which is one of the mainly-addressed spots in our method." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 671, + 432, + 684 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 671, + 432, + 684 + ], + "spans": [ + { + "bbox": [ + 306, + 671, + 432, + 684 + ], + "type": "text", + "content": "2.2. Multi-view Clustering" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": "Existing multi-view clustering (MVC) methods can be roughly classified into four categories, namely, canon-" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "text", + "content": "16526" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 97, + 70, + 500, + 281 + ], + "blocks": [ + { + "bbox": [ + 97, + 70, + 500, + 281 + ], + "lines": [ + { + "bbox": [ + 97, + 70, + 500, + 281 + ], + "spans": [ + { + "bbox": [ + 97, + 70, + 500, + 281 + ], + "type": "image", + "image_path": "2c883b2229c78c6a7083be34be73dea6f6ee16d84c01a9ef262cc3556f8719b8.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "lines": [ + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "spans": [ + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "text", + "content": "Figure 2: Overview of the proposed MHCN (taking two views as an example). MHCN assigns a hyperbolic autoencoder to each view, with the latent space grafted on the Poincaré ball for explicit hierarchies, where the exponential mapping function " + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "inline_equation", + "content": "\\exp_0" + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "text", + "content": " follows the hyperbolic encoder, and the hyperbolic decoder connects behind the logarithm mapping function " + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "inline_equation", + "content": "\\log_0" + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "text", + "content": ". The whole model is trained with the three joint learning objectives: (1) the multi-view alignment learning aims to align the hyperbolic embeddings " + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "inline_equation", + "content": "z_i^1" + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "inline_equation", + "content": "z_i^2" + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "text", + "content": ", (2) the reconstruction for HAE is used to project the complementary information in each view into the latent space, and (3) the hyperbolic uniformity learning guarantees " + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "inline_equation", + "content": "z_i^1" + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "inline_equation", + "content": "z_i^2" + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "text", + "content": " to distribute uniformly on the corresponding Poincaré balls, respectively. After " + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 46, + 289, + 545, + 387 + ], + "type": "text", + "content": "-fusion, the final MVHC tree can be decoded from the common hyperbolic representations." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 407, + 287, + 586 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 407, + 287, + 586 + ], + "spans": [ + { + "bbox": [ + 46, + 407, + 287, + 586 + ], + "type": "text", + "content": "ical correlation analysis-based [8], matrix factorization-based [3], subspace-based [27, 33] and graph-based [30] methods. Recently, deep MVC methods have been developed increasingly [35, 38, 49, 53, 59, 67]. However, most methods are limited to partitional clustering. The high computational complexities of these methods hinder the practicability and development of multi-view hierarchical clustering. To this end, research about MVHC has gradually emerged. Shallow MHC [68] roughly averages the cosine distance graphs for common latent features, which cannot achieve consistency of all views. A recent two-stage deep method CMHHC [37] presents an MVHC tree over aligned common representations through three modules, i.e., multiview alignment learning, unsupervised metric learning, and hyperbolic hierarchical clustering." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 587, + 287, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 587, + 287, + 647 + ], + "spans": [ + { + "bbox": [ + 46, + 587, + 287, + 647 + ], + "type": "text", + "content": "Unlike CMHHC, which regards multi-view representation learning and hierarchical clustering as two separate stages, our method unifies them into a one-stage training pipeline, where they can reinforce each other for naturally contributing to the final HC trees." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 658, + 160, + 671 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 658, + 160, + 671 + ], + "spans": [ + { + "bbox": [ + 47, + 658, + 160, + 671 + ], + "type": "text", + "content": "2.3. Hyperbolic Models" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": "There is extensive literature on hierarchical models conducted in the Euclidean space and its applications [22, 25, 58]. However, suffering from the inherent discrete na" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 407, + 545, + 528 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 407, + 545, + 528 + ], + "spans": [ + { + "bbox": [ + 304, + 407, + 545, + 528 + ], + "type": "text", + "content": "ture of trees, the Euclidean hierarchical models have difficulty in constructing the hierarchical structure of data explicitly, while hyperbolic models can. The underlying reason is that the exponential growth of the volume in hyperbolic space with its radius is analogous to the exponential growth of the number of leaves in a tree with its altitude, which is infeasible in the Euclidean space [43]. Thus, there has been an increasing interest in the generalization of hyperbolic neural networks to learn hyperbolic representations [6, 20, 26, 42, 50, 55]." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 537, + 361, + 550 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 537, + 361, + 550 + ], + "spans": [ + { + "bbox": [ + 306, + 537, + 361, + 550 + ], + "type": "text", + "content": "3. Method" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 558, + 545, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 545, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 545, + 665 + ], + "type": "text", + "content": "In this part, we propose a hyperbolic neural network model for MVHC, termed as Multi-view Hierarchical Clustering Network (MHCN), as shown in Figure 2. For clarity, we first briefly review the background of hyperbolic geometry and a specific hyperbolic model, i.e., the Poincaré ball. Then, we describe the architecture of HAE, define what desired trees look like through specific loss functions, and introduce the decoding strategy. Lastly, we summarize the whole optimization process." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "Let " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\{\\pmb{X}^m\\in \\mathbb{R}^{N\\times D_m}\\}_{m = 1}^M" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": " be a multi-view dataset including " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": " samples across " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": " views, where each " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\pmb{x}_i^m\\in \\mathbb{R}^{D_m}" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": " denotes the " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "-th instance of " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "D_{m}" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": " dimension from the " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "-th view. Our target is to present a unified method for" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16527" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "type": "text", + "content": "clustering tree learning by searching over multi-view continuous hierarchical representations in hyperbolic space." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 106, + 133, + 118 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 106, + 133, + 118 + ], + "spans": [ + { + "bbox": [ + 47, + 106, + 133, + 118 + ], + "type": "text", + "content": "3.1. Preliminaries" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 126, + 287, + 175 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 126, + 287, + 175 + ], + "spans": [ + { + "bbox": [ + 47, + 126, + 287, + 175 + ], + "type": "text", + "content": "We first introduce the Riemannian geometry and the Poincaré ball model of hyperbolic geometry, with which we build the hyperbolic autoencoders for our model. A more detailed review can be found in the appendix." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 194, + 178, + 208 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 194, + 178, + 208 + ], + "spans": [ + { + "bbox": [ + 47, + 194, + 178, + 208 + ], + "type": "text", + "content": "3.1.1 Riemannian Geometry" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "spans": [ + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": "An " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": "-dimensional manifold " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{M}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " [19, 54] is a real and smooth space, which can be locally approximated to a linear " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": "-dimensional space " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\mathbb{R}^n" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " at each point " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\pmb{x} \\in \\mathcal{M}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": ". For any point " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\pmb{x}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " of the manifold " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{M}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": ", the corresponding local tangent space " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_x\\mathcal{M}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": ", is the first order linear approximation of " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{M}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " around the point " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\pmb{x}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": ". The related metric tensor " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "g_x: \\mathcal{T}_x\\mathcal{M} \\times \\mathcal{T}_x\\mathcal{M} \\to \\mathbb{R}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " defines an inner product on " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_x\\mathcal{M}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " and a Riemannian metric " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "g = (g_x)_{x \\in \\mathcal{M}}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " is a set of such inner products on " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{M}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": ". In this way, a Riemannian manifold can be presented as a matching tuple " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "(\\mathcal{M}, g)" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": ". With " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "g_x" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": ", the local geometric attributions of " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_x\\mathcal{M}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " are accessible, and then the global distances can be achieved by integrating the local properties together. To project a tangent vector " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " in " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_x\\mathcal{M}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " onto " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{M}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " along a geodesic with constant velocity, the exponential map " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\exp_x: \\mathcal{T}_x\\mathcal{M} \\to \\mathcal{M}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " is given, and the inverse form is logarithmic map " + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "inline_equation", + "content": "\\log_x: \\mathcal{M} \\to \\mathcal{T}_x\\mathcal{M}" + }, + { + "bbox": [ + 47, + 215, + 289, + 420 + ], + "type": "text", + "content": " [20, 52, 55]. More detailed review is in the appendix." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 439, + 273, + 451 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 439, + 273, + 451 + ], + "spans": [ + { + "bbox": [ + 47, + 439, + 273, + 451 + ], + "type": "text", + "content": "3.1.2 Poincaré Ball Model of Hyperbolic Geometry" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "spans": [ + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "content": "Many studies [12, 21, 47] have demonstrated that data representations in most machine learning applications lie on a Riemannian manifold [32]. Later on, how to generalize neural networks to a Riemannian space has made remarkable progress [15, 42, 45]. An " + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "content": "-dimensional hyperbolic space " + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "inline_equation", + "content": "\\mathbb{H}^n" + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "content": " is an " + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "content": "-dimensional Riemannian manifold with constant negative curvature [2, 4]. We choose to perform our model on the " + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "content": "-dimensional Poincaré ball " + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "inline_equation", + "content": "(\\mathbb{B}^n,g^{\\mathbb{B}})" + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "content": " with a constant negative curvature " + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "inline_equation", + "content": "-1" + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "inline_equation", + "content": "\\mathbb{B}^n = \\{\\pmb {x}\\in \\mathbb{R}^n:||\\pmb {x}||^2 < 1\\}" + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "content": " is an open ball of curvature " + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "inline_equation", + "content": "-1" + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "content": ", and its hyperbolic metric tensor " + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "inline_equation", + "content": "g_{\\pmb{x}}^{\\mathbb{B}} = \\lambda_{\\pmb{x}}^{2}g^{E}" + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "content": " is conformal to the Euclidean one. " + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "inline_equation", + "content": "\\lambda_{\\pmb{x}}^{2} = \\frac{2}{1 - ||\\pmb{x}||^{2}}" + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "content": " is a conformal factor, and " + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "inline_equation", + "content": "g^{E} = I_{n}" + }, + { + "bbox": [ + 47, + 460, + 287, + 616 + ], + "type": "text", + "content": " denotes the dot product in the Euclidean space." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "type": "text", + "content": "Given " + }, + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "type": "inline_equation", + "content": "z, z' \\in \\mathbb{B}^n" + }, + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "type": "inline_equation", + "content": "t \\in \\mathcal{T}_z\\mathbb{B}^n" + }, + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "type": "text", + "content": ", the exponential map " + }, + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\exp_z: \\mathcal{T}_z\\mathbb{B}^n \\to \\mathbb{B}^n" + }, + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "type": "text", + "content": " and the logarithm map " + }, + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\log_z: \\mathbb{B}^n \\to \\mathcal{T}_z\\mathbb{B}^n" + }, + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "type": "text", + "content": " realize the projection from the Euclidean space onto the Poincaré ball and vice versa, respectively. To enable the mathematical operations for hyperbolic space models, the framework of gyrovector spaces provides the algebraic setting for the hyperbolic geometry. With the Möbius Addition " + }, + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\oplus" + }, + { + "bbox": [ + 47, + 617, + 288, + 714 + ], + "type": "text", + "content": " [60], the closed-form expressions of" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 72, + 470, + 85 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 470, + 85 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 470, + 85 + ], + "type": "inline_equation", + "content": "\\exp_z" + }, + { + "bbox": [ + 306, + 72, + 470, + 85 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 72, + 470, + 85 + ], + "type": "inline_equation", + "content": "\\log_z" + }, + { + "bbox": [ + 306, + 72, + 470, + 85 + ], + "type": "text", + "content": " are respectively given by" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 315, + 91, + 545, + 123 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 91, + 545, + 123 + ], + "spans": [ + { + "bbox": [ + 315, + 91, + 545, + 123 + ], + "type": "interline_equation", + "content": "\\exp_ {z} (\\boldsymbol {t}) = \\boldsymbol {z} \\oplus \\left(\\tanh \\left(\\frac {\\lambda_ {z} \\| \\boldsymbol {t} \\|}{2}\\right) \\frac {\\boldsymbol {t}}{\\| \\boldsymbol {t} \\|}\\right), \\tag {1}", + "image_path": "ee2d2404a7cff2ed3cbabaf05e776ea0bd537fe931eccf31399b2428ea50ca68.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 315, + 119, + 526, + 144 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 119, + 526, + 144 + ], + "spans": [ + { + "bbox": [ + 315, + 119, + 526, + 144 + ], + "type": "interline_equation", + "content": "\\log_ {z} (z ^ {\\prime}) = \\frac {2}{\\lambda_ {z}} \\mathrm {a r c t a n h} (| | - z \\oplus z ^ {\\prime} | |) \\frac {- z \\oplus z ^ {\\prime}}{| | - z \\oplus z ^ {\\prime} | |}.", + "image_path": "c3a473479b7ec32fe67f3e6da21eeadc4424fce270f343586eb1eff0293b3322.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 151, + 545, + 175 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 151, + 545, + 175 + ], + "spans": [ + { + "bbox": [ + 306, + 151, + 545, + 175 + ], + "type": "text", + "content": "For the convenience in practice, " + }, + { + "bbox": [ + 306, + 151, + 545, + 175 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 306, + 151, + 545, + 175 + ], + "type": "text", + "content": " is usually set to the origin " + }, + { + "bbox": [ + 306, + 151, + 545, + 175 + ], + "type": "inline_equation", + "content": "\\mathbf{0}" + }, + { + "bbox": [ + 306, + 151, + 545, + 175 + ], + "type": "text", + "content": ", so the " + }, + { + "bbox": [ + 306, + 151, + 545, + 175 + ], + "type": "inline_equation", + "content": "\\exp_z" + }, + { + "bbox": [ + 306, + 151, + 545, + 175 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 151, + 545, + 175 + ], + "type": "inline_equation", + "content": "\\log_z" + }, + { + "bbox": [ + 306, + 151, + 545, + 175 + ], + "type": "text", + "content": " can be simplified as" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 358, + 180, + 545, + 213 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 358, + 180, + 545, + 213 + ], + "spans": [ + { + "bbox": [ + 358, + 180, + 545, + 213 + ], + "type": "interline_equation", + "content": "\\exp_ {\\mathbf {0}} (\\boldsymbol {t}) = \\tanh (| | \\boldsymbol {t} | |) \\frac {\\boldsymbol {t}}{| | \\boldsymbol {t} | |}), \\tag {2}", + "image_path": "0c96bc4b40f17a5fa178ba4501c9f3481a87e8307fa9f4ac3040825e64116f30.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 358, + 208, + 494, + 233 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 358, + 208, + 494, + 233 + ], + "spans": [ + { + "bbox": [ + 358, + 208, + 494, + 233 + ], + "type": "interline_equation", + "content": "\\log_ {\\mathbf {0}} \\left(\\boldsymbol {z} ^ {\\prime}\\right) = \\operatorname {a r c t a n h} \\left(\\left| \\left| \\boldsymbol {z} ^ {\\prime} \\right| \\right|\\right) \\frac {\\boldsymbol {z} ^ {\\prime}}{\\left| \\left| \\boldsymbol {z} ^ {\\prime} \\right| \\right|}.", + "image_path": "50faf861d9dca5f27227d607f8c9c15394cbb8ded10dc758df5efe5961c0eba7.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 239, + 545, + 289 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 239, + 545, + 289 + ], + "spans": [ + { + "bbox": [ + 305, + 239, + 545, + 289 + ], + "type": "text", + "content": "By means of the above main operations " + }, + { + "bbox": [ + 305, + 239, + 545, + 289 + ], + "type": "inline_equation", + "content": "\\exp_0(t)" + }, + { + "bbox": [ + 305, + 239, + 545, + 289 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 239, + 545, + 289 + ], + "type": "inline_equation", + "content": "\\log_0(z')" + }, + { + "bbox": [ + 305, + 239, + 545, + 289 + ], + "type": "text", + "content": ", MHCN is able to perform the basic transformations of the latent representations between the Euclidean space and the hyperbolic space." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 294, + 448, + 307 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 294, + 448, + 307 + ], + "spans": [ + { + "bbox": [ + 306, + 294, + 448, + 307 + ], + "type": "text", + "content": "3.2. Hyperbolic Autoencoders" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 312, + 545, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 312, + 545, + 529 + ], + "spans": [ + { + "bbox": [ + 304, + 312, + 545, + 529 + ], + "type": "text", + "content": "The conventional approach to learning useful representations is through a regular Euclidean autoencoder [18, 23, 64]. However, there has been significant interest in hierarchical representation learning using non-Euclidean geometry, specifically the hyperbolic space. This attention arises from the fact that the number of leaf nodes in tree structures increases exponentially with depth, mirroring the exponential growth of the hyperbolic surface area with its radius, while the growth in the Euclidean space is polynomial [6, 20, 52, 55]. As a result, we augment the standard autoencoder with hyperbolic geometry in the embedding space, and propose a novel multi-view hyperbolic model consisting of multiple hyperbolic autoencoders assigned for different views, shown in Figure 2. Each hyperbolic autoencoder's geometry-aware encoder and decoder are constructed via the introduced exponential and logarithmic map functions in Eq.(2). We show the detailed structures of the encoders and the decoders in the following." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 542, + 489, + 555 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 542, + 489, + 555 + ], + "spans": [ + { + "bbox": [ + 306, + 542, + 489, + 555 + ], + "type": "text", + "content": "3.2.1 Encoder with the Exponential Map" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "spans": [ + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "text", + "content": "With regard to the " + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "text", + "content": "-th view " + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "inline_equation", + "content": "\\pmb{X}^{m}" + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "text", + "content": ", the encoder of " + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "text", + "content": "-th HAE, i.e., " + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{enc}}(\\pmb{X}^{m};\\theta_{\\mathrm{enc}}^{m}): \\pmb{X}^{m} \\in \\mathbb{R}^{D_{m}} \\to \\pmb{Z}_{\\mathrm{hyp}}^{m} \\in \\mathbb{B}^{d}" + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "text", + "content": ", is designed as a regular Euclidean encoder followed by the exponential map " + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "inline_equation", + "content": "\\exp_0(\\cdot)" + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "text", + "content": ", along with which the output of the hyperbolic encoder is projected onto the Poincaré ball. " + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "inline_equation", + "content": "\\pmb{Z}_{\\mathrm{hyp}}^{m}" + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "text", + "content": " represents the " + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "text", + "content": "-dimensional hyperbolic latent code with explicit hierarchical patterns and " + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "inline_equation", + "content": "\\theta_{\\mathrm{enc}}^{m}" + }, + { + "bbox": [ + 305, + 560, + 545, + 657 + ], + "type": "text", + "content": " denotes the encoder parameters." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 306, + 670, + 483, + 683 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 670, + 483, + 683 + ], + "spans": [ + { + "bbox": [ + 306, + 670, + 483, + 683 + ], + "type": "text", + "content": "3.2.2 Decoder with the Logarithm Map" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 305, + 689, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 545, + 715 + ], + "type": "text", + "content": "Similar to the hyperbolic encoder, the decoder of the " + }, + { + "bbox": [ + 305, + 689, + 545, + 715 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 305, + 689, + 545, + 715 + ], + "type": "text", + "content": "-th HAE, " + }, + { + "bbox": [ + 305, + 689, + 545, + 715 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{dec}}(\\pmb{X}^m;\\theta_{\\mathrm{dec}}^m): \\pmb{Z}_{\\mathrm{hyp}}^m \\in \\mathbb{B}^d \\to \\pmb{X}^m \\in \\mathbb{R}^{D_m}" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16528" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": "for the " + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": "-th view " + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "\\mathbf{X}^m" + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": " which is parameterized by " + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "\\theta_{\\mathrm{dec}}^m" + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": ", is constituted of a regular Euclidean decoder preprocessed by the logarithm map " + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "\\log_0(\\cdot)" + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": ", projecting the latent hyperbolic features back to the Euclidean space." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 127, + 242, + 139 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 127, + 242, + 139 + ], + "spans": [ + { + "bbox": [ + 47, + 127, + 242, + 139 + ], + "type": "text", + "content": "3.3. Loss Functions for Desired HC Trees" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 145, + 287, + 240 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 145, + 287, + 240 + ], + "spans": [ + { + "bbox": [ + 46, + 145, + 287, + 240 + ], + "type": "text", + "content": "High-quality MVHC trees should: 1) preserve the intrinsic hierarchy of each view via learned hyperbolic embeddings, 2) make full use of multi-view complementary and consistent information to acquire common hierarchical representations, and 3) not increase hierarchies without strong necessity [1, 7, 14, 62]. In this section, based on the structure of multi-view HAEs, we design the total loss functions for our model to realize the above characteristics:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 119, + 251, + 287, + 263 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 119, + 251, + 287, + 263 + ], + "spans": [ + { + "bbox": [ + 119, + 251, + 287, + 263 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\mathrm {m v l}} + \\mathcal {L} _ {\\mathrm {u n i}}. \\tag {3}", + "image_path": "40211a56d6b6c2041d311214ca6be2d309a7b1433f1029ecc5299e90d6b64251.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 273, + 287, + 321 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 273, + 287, + 321 + ], + "spans": [ + { + "bbox": [ + 46, + 273, + 287, + 321 + ], + "type": "text", + "content": "In our model, we jointly achieve the multi-view consistency and complementarity in the hyperbolic common-view space by optimizing the combined loss " + }, + { + "bbox": [ + 46, + 273, + 287, + 321 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{mvl}}" + }, + { + "bbox": [ + 46, + 273, + 287, + 321 + ], + "type": "text", + "content": " of the multi-view alignment loss " + }, + { + "bbox": [ + 46, + 273, + 287, + 321 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{align}}" + }, + { + "bbox": [ + 46, + 273, + 287, + 321 + ], + "type": "text", + "content": " and the reconstruction loss " + }, + { + "bbox": [ + 46, + 273, + 287, + 321 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{rc}}" + }, + { + "bbox": [ + 46, + 273, + 287, + 321 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 102, + 331, + 287, + 342 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 102, + 331, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 102, + 331, + 287, + 342 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {m v l}} = \\alpha \\mathcal {L} _ {\\text {a l i g n}} + (1 - \\alpha) \\mathcal {L} _ {\\mathrm {r c}}, \\tag {4}", + "image_path": "3f7da26a253d15f08024b656d1aee75ae2286c395432ec92860daa2690ebb9e4.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 352, + 287, + 375 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 352, + 287, + 375 + ], + "spans": [ + { + "bbox": [ + 46, + 352, + 287, + 375 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 352, + 287, + 375 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 352, + 287, + 375 + ], + "type": "text", + "content": " is a trade-off coefficient to balance the effects of consistency and complementarity for multi-view learning." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 376, + 287, + 507 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 376, + 287, + 507 + ], + "spans": [ + { + "bbox": [ + 46, + 376, + 287, + 507 + ], + "type": "text", + "content": "Learning view-common consistency with the multi-view alignment loss. The extracted common representations " + }, + { + "bbox": [ + 46, + 376, + 287, + 507 + ], + "type": "inline_equation", + "content": "\\{Z_{\\mathrm{hyp}}^m = f_{\\mathrm{enc}}(X^m)\\}_{m=1}^M" + }, + { + "bbox": [ + 46, + 376, + 287, + 507 + ], + "type": "text", + "content": " are expected not only to uncover the complementary relationships among different views but also to contain sufficient consensus information of all views. To achieve consistency across multiple views, we apply distance and similarity-based alignment by conducting a multi-view alignment loss endowed on the hyperbolic embeddings. Here, we consider the cosine distance between two latent features " + }, + { + "bbox": [ + 46, + 376, + 287, + 507 + ], + "type": "inline_equation", + "content": "z_i^{m_1}" + }, + { + "bbox": [ + 46, + 376, + 287, + 507 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 376, + 287, + 507 + ], + "type": "inline_equation", + "content": "z_j^{m_2}" + }, + { + "bbox": [ + 46, + 376, + 287, + 507 + ], + "type": "text", + "content": " as the similarity measurement for multi-view alignment:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 95, + 515, + 287, + 544 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 95, + 515, + 287, + 544 + ], + "spans": [ + { + "bbox": [ + 95, + 515, + 287, + 544 + ], + "type": "interline_equation", + "content": "\\sin \\left(\\boldsymbol {z} _ {i} ^ {m _ {1}}, \\boldsymbol {z} _ {i} ^ {m _ {2}}\\right) = \\frac {\\left\\langle \\boldsymbol {z} _ {i} ^ {m _ {1}} , \\boldsymbol {z} _ {j} ^ {m _ {2}} \\right\\rangle}{\\left| \\left| \\boldsymbol {z} _ {i} ^ {m _ {1}} \\right| \\right| \\left| \\left| \\boldsymbol {z} _ {j} ^ {m _ {2}} \\right| \\right|}. \\tag {5}", + "image_path": "39c2881a8a07608b7fa10117b98c18a0f860a67b0bf3a9b0aee0767bc4b0b344.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 552, + 287, + 635 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 552, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 46, + 552, + 287, + 635 + ], + "type": "text", + "content": "Supported by the conformality property of the Riemannian geometry, i.e., the Poincaré ball preserves the same angels as the Euclidean space, the computation of the cosine similarity in the Euclidean space is equal to that on the Poincaré ball [20, 55]. Besides, unlike the geodesic distances, values of the cosine distances are kept in a certain range, which is friendly to optimization processes." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 636, + 287, + 674 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 636, + 287, + 674 + ], + "spans": [ + { + "bbox": [ + 47, + 636, + 287, + 674 + ], + "type": "text", + "content": "Then, the multi-view alignment loss between the hyperbolic embeddings of the same instance from any two views " + }, + { + "bbox": [ + 47, + 636, + 287, + 674 + ], + "type": "inline_equation", + "content": "Z_{\\mathrm{hyp}}^{m_1}, Z_{\\mathrm{hyp}}^{m_2}" + }, + { + "bbox": [ + 47, + 636, + 287, + 674 + ], + "type": "text", + "content": " is given by:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 74, + 683, + 287, + 715 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 683, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 74, + 683, + 287, + 715 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {a l i g n}} ^ {(m _ {1}, m _ {2})} = - \\frac {1}{N} \\sum_ {i = 1} ^ {N} \\sin \\left(\\boldsymbol {z} _ {i} ^ {m _ {1}}, \\boldsymbol {z} _ {i} ^ {m _ {2}}\\right) / \\tau_ {\\text {a l i g n}}, \\tag {6}", + "image_path": "eb221cb40ea7f98da31dec1aad88bfeb1d4860d76515b5eb4b6ffee66897faae.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 72, + 545, + 132 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 132 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 132 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 72, + 545, + 132 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{align}}" + }, + { + "bbox": [ + 304, + 72, + 545, + 132 + ], + "type": "text", + "content": " is used as a temperature parameter for the scaled distance function. Here, we notice that CMHHC [37] also serves to learn common representations. However, CMHHC aligns Euclidean features, while MHCN directly makes the corresponding hyperbolic embeddings closer." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 133, + 545, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 133, + 545, + 156 + ], + "spans": [ + { + "bbox": [ + 304, + 133, + 545, + 156 + ], + "type": "text", + "content": "Therefore, the complete multi-view alignment loss across all view pairs is formulated as:" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 346, + 162, + 545, + 195 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 346, + 162, + 545, + 195 + ], + "spans": [ + { + "bbox": [ + 346, + 162, + 545, + 195 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {a l i g n}} = \\sum_ {m _ {1} = 1} ^ {M} \\sum_ {m _ {2} = 1, m _ {1} \\neq m _ {2}} ^ {M} \\mathcal {L} _ {\\text {a l i g n}} ^ {(m _ {1}, m _ {2})}. \\tag {7}", + "image_path": "7b0cf2362eb3d1b1f20fa49fe2dbd92870bbab04d8a5248b56cd1630741403a4.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 201, + 545, + 368 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 201, + 545, + 368 + ], + "spans": [ + { + "bbox": [ + 304, + 201, + 545, + 368 + ], + "type": "text", + "content": "Learning view-private complementarity with the reconstruction loss of HAEs. In multi-view representation learning models, autoencoders are widely used for their impressive strengths, such as preserving the useful view-private information and preventing data points from collapsing to a small number of clusters [29, 67]. In our multi-view hierarchical clustering model, the learned representations by multiple HAEs consider the preservation of the local hierarchical structure within each view. This implies that similar instances from each view remain close to each other in the hyperbolic space, while the latent codes obtained from dissimilar instances remain distant from one another. To this end, the total reconstruction loss function of HAEs for multiple views is formulated as" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 374, + 545, + 417 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 374, + 545, + 417 + ], + "spans": [ + { + "bbox": [ + 307, + 374, + 545, + 417 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {r c}} = \\sum_ {m = 1} ^ {M} \\mathcal {L} _ {\\mathrm {r c}} ^ {m} = \\sum_ {m = 1} ^ {M} \\frac {1}{N} \\sum_ {i = 1} ^ {N} \\left| \\left| \\boldsymbol {x} _ {i} ^ {m} - f _ {\\mathrm {d e c}} \\left(f _ {\\mathrm {e n c}} \\left(\\boldsymbol {x} _ {i} ^ {m}\\right)\\right) \\right| \\right| _ {2} ^ {2}, \\tag {8}", + "image_path": "c98dcf2f93ae64f8d5b8a111bdca7893085da6351094ed5e951ba8d4353cc7e6.jpg" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 418, + 545, + 439 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 418, + 545, + 439 + ], + "spans": [ + { + "bbox": [ + 304, + 418, + 545, + 439 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 418, + 545, + 439 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{rc}}^m" + }, + { + "bbox": [ + 304, + 418, + 545, + 439 + ], + "type": "text", + "content": " is the corresponding " + }, + { + "bbox": [ + 304, + 418, + 545, + 439 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 304, + 418, + 545, + 439 + ], + "type": "text", + "content": "-th view objective to reconstruct " + }, + { + "bbox": [ + 304, + 418, + 545, + 439 + ], + "type": "inline_equation", + "content": "\\pmb{X}^{m}" + }, + { + "bbox": [ + 304, + 418, + 545, + 439 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 441, + 545, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 441, + 545, + 536 + ], + "spans": [ + { + "bbox": [ + 304, + 441, + 545, + 536 + ], + "type": "text", + "content": "Learning tree balancing property with the hyperbolic uniformity loss. Through the multi-view alignment and reconstruction related to the Poincaré ball, our model obtains reliable multi-view representations and discovers the hierarchical structure of each view simultaneously. Last but not least, a hierarchical clustering tree with explicit balancing property provides fewer hierarchies and higher interpretability than skewed ones." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 537, + 545, + 608 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 537, + 545, + 608 + ], + "spans": [ + { + "bbox": [ + 304, + 537, + 545, + 608 + ], + "type": "text", + "content": "Consequently, we leverage the uniformity of the hyperbolic embedding distribution located on the Poincaré ball to learn separable features and enhance the contribution of the balanced affinity. Concretely, considering the form of Gaussian potential kernel [11, 40], we define a hyperbolic uniformity objective based on the cosine distance as:" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 311, + 614, + 545, + 647 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 614, + 545, + 647 + ], + "spans": [ + { + "bbox": [ + 311, + 614, + 545, + 647 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {u n i}} = \\sum_ {m = 1} ^ {M} \\frac {1}{N ^ {2}} \\sum_ {i = 1} ^ {N} \\sum_ {j = 1} ^ {N} \\log \\left(e ^ {- t \\left(- \\operatorname {s i m} \\left(\\boldsymbol {z} _ {i} ^ {m}, \\boldsymbol {z} _ {j} ^ {m}\\right) / \\tau_ {\\mathrm {u n i}}\\right)}\\right). \\tag {9}", + "image_path": "76c28eb11f2de7cc201ca9cf7548eace11a781550aec0d14ae71772554ad79a3.jpg" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 654, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 545, + 712 + ], + "type": "text", + "content": "Still, the temperature parameter " + }, + { + "bbox": [ + 304, + 654, + 545, + 712 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{uni}}" + }, + { + "bbox": [ + 304, + 654, + 545, + 712 + ], + "type": "text", + "content": " is a scaling factor to the cosine distance. Intuitively, the hyperbolic uniformity loss encourages the latent hyperbolic embeddings to push farther away from each other and to benefit the uniform global distribution of embeddings on the Poincaré ball." + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16529" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 286, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 286, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 286, + 85 + ], + "type": "text", + "content": "3.4. From Hyperbolic Embeddings to Binary Trees" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 90, + 287, + 258 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 90, + 287, + 258 + ], + "spans": [ + { + "bbox": [ + 46, + 90, + 287, + 258 + ], + "type": "text", + "content": "We first adopt " + }, + { + "bbox": [ + 46, + 90, + 287, + 258 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 46, + 90, + 287, + 258 + ], + "type": "text", + "content": "-fusion [55] to concatenate the optimal hyperbolic embeddings from multiple views into the common-view space, to guarantee the concatenated norms maintain upper-bounded by the radius of the Poincaré ball. To output an intuitive HC tree from the common continuous hyperbolic representations on the Poincaré ball back to discrete HC trees with low error, we apply the decoding strategy proposed by [5], which realizes the underlying correspondence between the hyperbolic embeddings and the HC trees with low-error. This bottom-up decoding algorithm decodes the common hyperbolic embeddings by measuring the similarity of any two embeddings with the distance from their lowest common ancient (LCA) to the origin of the ball and merging more similar ones iteratively." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 266, + 169, + 278 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 266, + 169, + 278 + ], + "spans": [ + { + "bbox": [ + 47, + 266, + 169, + 278 + ], + "type": "text", + "content": "3.5. Optimization Process" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 285, + 286, + 357 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 285, + 286, + 357 + ], + "spans": [ + { + "bbox": [ + 46, + 285, + 286, + 357 + ], + "type": "text", + "content": "The whole optimization process of MHCN is summarized in the appendix. We train this model by adopting a one-stage pipeline of mini-batch gradient descent, making our method feasible to scale up to large-scale scenarios. Concretely, the integrated framework of multiple HAEs is optimized collectively with the " + }, + { + "bbox": [ + 46, + 285, + 286, + 357 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{total}}" + }, + { + "bbox": [ + 46, + 285, + 286, + 357 + ], + "type": "text", + "content": " in Eq.(3)." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 368, + 127, + 380 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 368, + 127, + 380 + ], + "spans": [ + { + "bbox": [ + 47, + 368, + 127, + 380 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 388, + 286, + 422 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 388, + 286, + 422 + ], + "spans": [ + { + "bbox": [ + 47, + 388, + 286, + 422 + ], + "type": "text", + "content": "In the following, we conduct experiments to verify the effectiveness and efficiency of the proposed method and analyze the results." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 431, + 173, + 444 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 431, + 173, + 444 + ], + "spans": [ + { + "bbox": [ + 47, + 431, + 173, + 444 + ], + "type": "text", + "content": "4.1. Experimental Settings" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 450, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 450, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 450, + 287, + 713 + ], + "type": "text", + "content": "Datasets. Following literature [37, 53, 57, 59, 63, 67], we adopt seven common multi-view datasets in our experiments, including five regular-scale datasets (MNIST-USPS, BDGP, Caltech, COIL-20 and BBCSport) and two largescale datasets (Multi-Fashion and NR-MNIST). MNIST-USPS [53] is a handwritten digital dataset with 5,000 images from 10 categories, where the digits from MNIST and USPS are two views. BDGP [35] includes 2,500 images of Drosophila embryos divided into 5 classes, characterized by visual and textual features. Caltech [16] containing 1,400 RGB images of 7 classes is constructed with 5 different visual descriptors. COIL-20 [59] contains 480 grayscale images of 20 classes, described by 3 different angles. BBCSport [41] is a text dataset in 5 topic areas. It consists of 544 documents collected from the BBC Sport website of sports news articles, related to 2 different viewpoints. Multi-Fashion [66] is also a grayscale image dataset on 10 kinds of 10,000 fashionable products. Three different views are represented by three products from the same category. In terms of NR-MNIST [65], we regard the noise-processed MNIST and the rotated-processed MNIST as two views. We use 60,000 image pairs for the general MVHC" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 72, + 544, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 544, + 95 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 544, + 95 + ], + "type": "text", + "content": "experiments in Section 4.2, and use the rest 10,000 image pairs for the inductive HC experiments in Section 4.5." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 97, + 545, + 289 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 97, + 545, + 289 + ], + "spans": [ + { + "bbox": [ + 304, + 97, + 545, + 289 + ], + "type": "text", + "content": "Dendrogram Purity measurement for HC. The tree structures with various fine-grained partitional clusters can be truncated at any level. Therefore, instead of using partitional clustering metrics, e.g., ACC and NMI, evaluating the performance of a clustering tree needs a much more comprehensive measurement. To this end, we adopt the Dendrogram Purity (DP) measurement to evaluate the quality of the clustering tree [31, 37, 43], which computes the average purity over the descendant leaves of LCA of all data point pairs belonging to the same ground-truth clusters. Trees with higher DP results tend to be more similar to the ground-truth clusters. Note that the Dasgupta's Cost, another HC metric applied in [5], requires an uncontroversial predefined similarity measurement as input, which is not available in our settings. The detailed reasons for using DP and not using ACC or NMI are given in the appendix." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 289, + 545, + 396 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 289, + 545, + 396 + ], + "spans": [ + { + "bbox": [ + 304, + 289, + 545, + 396 + ], + "type": "text", + "content": "Baseline methods. The baselines include three kinds of methods as follows: (1) shallow discrete single-view hierarchical agglomerative clustering methods (HACs), e.g., Single-linkage, Complete-linkage, Average-linkage, and Ward-linkage algorithms; (2) deep continuous single-view HC approaches, e.g., UFit and HypHC, where we concatenate the raw features of all views into a single-view pattern [53]; and (3) State-of-the-art MVHC methods, including MHC and CMHHC." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 396, + 545, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 396, + 545, + 552 + ], + "spans": [ + { + "bbox": [ + 304, + 396, + 545, + 552 + ], + "type": "text", + "content": "Implementation. The proposed network architecture is trained with the PyTorch platform. The fully connected networks with the same architecture are adopted to implement the HAEs for all views in our MHCN. We use the minimal dataset-dependent hyperparameter set for tuning. Since the parameters in hyperbolic space can be considered as Euclidean parameters computed through " + }, + { + "bbox": [ + 304, + 396, + 545, + 552 + ], + "type": "inline_equation", + "content": "Z_{\\mathrm{hyp}}^{m} = \\exp_{0}(Z_{\\mathrm{tan}}^{m})" + }, + { + "bbox": [ + 304, + 396, + 545, + 552 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 396, + 545, + 552 + ], + "type": "inline_equation", + "content": "Z_{\\mathrm{tan}}^{m} \\in \\mathbb{R}^{d}" + }, + { + "bbox": [ + 304, + 396, + 545, + 552 + ], + "type": "text", + "content": ", we directly train our model by using the common optimizer Adam. All experiments are conducted on a Linux Server with an Intel Xeon E5-2630 v4 CPU, an NVIDIA TITAN Xp GPU, and 128GB RAM. More implementation details are provided in the supplementary materials." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 563, + 492, + 575 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 563, + 492, + 575 + ], + "spans": [ + { + "bbox": [ + 306, + 563, + 492, + 575 + ], + "type": "text", + "content": "4.2. Experimental Results and Analysis" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": "The comparison results are shown in Table 1. DP results of the baseline methods on all datasets except NR-MNSIT are directly taken from [37]. We can observe that: (1) MHCN outperforms the second-best baseline, i.e., CMHHC, on all datasets. Unlike two-stage CMHHC, our one-stage framework relieves the separation of multi-view representation learning and hierarchical clustering and naturally makes two associated processes boost each other. (2) Compared with the representative shallow MHC, our deep model also obtains considerable improvements on all datasets. MHC is not capable of learning rich multi-view" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "16530" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 56, + 70, + 539, + 214 + ], + "blocks": [ + { + "bbox": [ + 56, + 70, + 539, + 214 + ], + "lines": [ + { + "bbox": [ + 56, + 70, + 539, + 214 + ], + "spans": [ + { + "bbox": [ + 56, + 70, + 539, + 214 + ], + "type": "table", + "html": "
MethodMNIST-USPSBDGPCaltechCOIL-20BBCSportMulti-FashionNR-MNIST
HAC-Single29.81%61.88%23.67%72.56%27.66%27.89%25.77%
HAC-Complete54.36%56.57%30.19%69.95%34.78%48.72%27.71%
HAC-Average69.67%45.91%30.90%73.14%29.05%65.70%59.74%
HAC-Ward80.38%58.61%35.69%80.81%62.65%72.33%76.91%
UFit21.67%69.20%19.00%55.41%30.33%25.94%OOM
HyperHC32.99%31.21%22.46%28.50%29.08%25.65%OOM
MHC78.27%89.14%45.22%66.50%42.43%54.81%40.87%
CMHHC94.49%91.53%66.52%84.89%53.50%96.25%OOM
MHCN99.22%96.22%77.14%94.70%78.93%97.67%98.71%
", + "image_path": "0d0bcd8dfb93667aedf672831f87798838c4156cca528a0d83dbae0244e08ba1.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 48, + 256, + 548, + 349 + ], + "blocks": [ + { + "bbox": [ + 46, + 221, + 546, + 246 + ], + "lines": [ + { + "bbox": [ + 46, + 221, + 546, + 246 + ], + "spans": [ + { + "bbox": [ + 46, + 221, + 546, + 246 + ], + "type": "text", + "content": "Table 1: Comparison results. Higher DP values indicate better clustering performance. \"OOM\" is out-of-memory on our server." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 256, + 548, + 349 + ], + "lines": [ + { + "bbox": [ + 48, + 256, + 548, + 349 + ], + "spans": [ + { + "bbox": [ + 48, + 256, + 548, + 349 + ], + "type": "table", + "html": "
VariantsMNIST-USPSBDGPCaltechCOIL-20BBCSportMulti-FashionNR-MNIST
MHCN (complete)99.22%96.22%77.14%94.70%78.93%97.67%98.71%
w/o Lrc99.07%95.46%*75.17%†93.85%78.38%96.78%*98.20%
w/o Lalign41.29%†56.83%†57.56%†78.68%†40.58%†53.16%†28.36%†
w/o Luni19.42%†44.31%†36.69%†51.57%†28.52%†40.37%†32.64%†
Euclidean AEs92.72%†52.47%†32.50%†70.69%†56.58%†60.55%†53.30%†
", + "image_path": "5a961c0052161224ca2b66696752342adc8a918235b499c780117ca1864653ac.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 50, + 355, + 541, + 369 + ], + "lines": [ + { + "bbox": [ + 50, + 355, + 541, + 369 + ], + "spans": [ + { + "bbox": [ + 50, + 355, + 541, + 369 + ], + "type": "text", + "content": "Table 2: Ablation study of our method. “*” and “†” indicate that the difference is significant at 0.05 and 0.01, respectively." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "type": "image", + "bbox": [ + 73, + 378, + 222, + 440 + ], + "blocks": [ + { + "bbox": [ + 73, + 378, + 222, + 440 + ], + "lines": [ + { + "bbox": [ + 73, + 378, + 222, + 440 + ], + "spans": [ + { + "bbox": [ + 73, + 378, + 222, + 440 + ], + "type": "image", + "image_path": "9de1e42d495922a07a145a1bc5acc790a597ef9e5dcfde08944732ba83e07a6c.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 117, + 443, + 181, + 455 + ], + "lines": [ + { + "bbox": [ + 117, + 443, + 181, + 455 + ], + "spans": [ + { + "bbox": [ + 117, + 443, + 181, + 455 + ], + "type": "text", + "content": "(a) Without " + }, + { + "bbox": [ + 117, + 443, + 181, + 455 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{uni}}" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 223, + 379, + 371, + 439 + ], + "blocks": [ + { + "bbox": [ + 223, + 379, + 371, + 439 + ], + "lines": [ + { + "bbox": [ + 223, + 379, + 371, + 439 + ], + "spans": [ + { + "bbox": [ + 223, + 379, + 371, + 439 + ], + "type": "image", + "image_path": "2fabbc73164c0d5e7916e0a295df27126b751d119ffa43827afa14e8c87b85f1.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 265, + 442, + 338, + 455 + ], + "lines": [ + { + "bbox": [ + 265, + 442, + 338, + 455 + ], + "spans": [ + { + "bbox": [ + 265, + 442, + 338, + 455 + ], + "type": "text", + "content": "(b) With " + }, + { + "bbox": [ + 265, + 442, + 338, + 455 + ], + "type": "inline_equation", + "content": "0.1^{*}\\mathcal{L}_{\\mathrm{uni}}" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 468, + 547, + 529 + ], + "lines": [ + { + "bbox": [ + 46, + 468, + 547, + 529 + ], + "spans": [ + { + "bbox": [ + 46, + 468, + 547, + 529 + ], + "type": "text", + "content": "Figure 3: Illustrations of the effectiveness of hyperbolic uniformity learning. We visualize the hyperbolic embeddings and the top-35 non-leaf internal nodes of corresponding decoding dendrograms. Left: Distributions of the learned hyperbolic embeddings optimized by different weights of " + }, + { + "bbox": [ + 46, + 468, + 547, + 529 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{uni}}" + }, + { + "bbox": [ + 46, + 468, + 547, + 529 + ], + "type": "text", + "content": ", i.e., 0.0, 0.1, and 1.0. Right: Top-35 non-leaf internal nodes of corresponding decoding dendrograms. With the weight of " + }, + { + "bbox": [ + 46, + 468, + 547, + 529 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{uni}}" + }, + { + "bbox": [ + 46, + 468, + 547, + 529 + ], + "type": "text", + "content": " increasing, the distribution becomes uniform and the dendrograms are gradually balanced." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 373, + 379, + 522, + 439 + ], + "blocks": [ + { + "bbox": [ + 373, + 379, + 522, + 439 + ], + "lines": [ + { + "bbox": [ + 373, + 379, + 522, + 439 + ], + "spans": [ + { + "bbox": [ + 373, + 379, + 522, + 439 + ], + "type": "image", + "image_path": "0b77a8ddc5e55d3021a913016d9bfe2ec6f19276cbf84e1bc2d7b38036d463d3.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 420, + 442, + 471, + 455 + ], + "lines": [ + { + "bbox": [ + 420, + 442, + 471, + 455 + ], + "spans": [ + { + "bbox": [ + 420, + 442, + 471, + 455 + ], + "type": "text", + "content": "(c) With " + }, + { + "bbox": [ + 420, + 442, + 471, + 455 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{uni}}" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 549, + 289, + 706 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 549, + 289, + 706 + ], + "spans": [ + { + "bbox": [ + 46, + 549, + 289, + 706 + ], + "type": "text", + "content": "hierarchical representations as a result of poor hierarchical representation ability and ignorance of the balancing property of the tree structure. (3) Our method performs significantly better than all multi-view concatenation followed by single-view discrete or continuous HC methods. In contrast to concatenating features of all views simply, through learning the multi-view alignment and preserving each view's local relationships, MHCN encodes the meaningful common hierarchical representations across multiple views into the latent hyperbolic space. (4) The performance of MHCN on large-scale NR-MNIST is much better than other comparison methods. Meanwhile, conducting deep methods, like UFit, HyperHC, and CMHHC, on oversized NR-MNSIT re" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 549, + 545, + 586 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 549, + 545, + 586 + ], + "spans": [ + { + "bbox": [ + 305, + 549, + 545, + 586 + ], + "type": "text", + "content": "sults in high time complexity and unbearable memory cost. The scalability of MHCN can be attributed to the one-stage pipeline to optimize the total loss by batch-based training." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 597, + 407, + 609 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 597, + 407, + 609 + ], + "spans": [ + { + "bbox": [ + 306, + 597, + 407, + 609 + ], + "type": "text", + "content": "4.3. Ablation Studies" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 616, + 545, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 616, + 545, + 700 + ], + "spans": [ + { + "bbox": [ + 304, + 616, + 545, + 700 + ], + "type": "text", + "content": "To further understand the effectiveness of all the factors of MHCN, we conduct ablation studies and report the results in Table 2. We mainly consider the following ablations, i.e., (a) MHCN without " + }, + { + "bbox": [ + 304, + 616, + 545, + 700 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{rc}}" + }, + { + "bbox": [ + 304, + 616, + 545, + 700 + ], + "type": "text", + "content": ", (b) MHCN without " + }, + { + "bbox": [ + 304, + 616, + 545, + 700 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{align}}" + }, + { + "bbox": [ + 304, + 616, + 545, + 700 + ], + "type": "text", + "content": ", (c) MHCN without " + }, + { + "bbox": [ + 304, + 616, + 545, + 700 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{uni}}" + }, + { + "bbox": [ + 304, + 616, + 545, + 700 + ], + "type": "text", + "content": ", and (d) MHCN with Euclidean autoencoders. We also report the significance of test results for the differences compared with MHCN." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "type": "text", + "content": "As shown in Table 2, " + }, + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{align}}" + }, + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{uni}}" + }, + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "type": "text", + "content": " both contribute" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16531" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 100, + 70, + 492, + 106 + ], + "blocks": [ + { + "bbox": [ + 100, + 70, + 492, + 106 + ], + "lines": [ + { + "bbox": [ + 100, + 70, + 492, + 106 + ], + "spans": [ + { + "bbox": [ + 100, + 70, + 492, + 106 + ], + "type": "table", + "html": "
Running TimeMHCNHAC-SingleHAC-CompleteHAC-AverageHAC-Ward
NR-MNIST900.92s1823.43s1903.12s2055.16s2204.11s
", + "image_path": "829c5a0e96a11adcef07f36f2c15e51d0393a59570748cbec5c1710eaac13f2d.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 153, + 115, + 440, + 127 + ], + "lines": [ + { + "bbox": [ + 153, + 115, + 440, + 127 + ], + "spans": [ + { + "bbox": [ + 153, + 115, + 440, + 127 + ], + "type": "text", + "content": "Table 3: Total time spent of MHCN and HACs on NR-MNIST dataset." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "type": "image", + "bbox": [ + 65, + 140, + 531, + 337 + ], + "blocks": [ + { + "bbox": [ + 65, + 140, + 531, + 337 + ], + "lines": [ + { + "bbox": [ + 65, + 140, + 531, + 337 + ], + "spans": [ + { + "bbox": [ + 65, + 140, + 531, + 337 + ], + "type": "image", + "image_path": "015c2a6544b227a6320fdffb513628017b043051a68ede74ad2df42045831a56.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 346, + 545, + 396 + ], + "lines": [ + { + "bbox": [ + 45, + 346, + 545, + 396 + ], + "spans": [ + { + "bbox": [ + 45, + 346, + 545, + 396 + ], + "type": "text", + "content": "Figure 4: The sampled sub-tree of LCA #19978 from the Multi-Fashion HC tree. We can observe that the sub-trees containing more similar kinds of products are closer, e.g., categories Shirt in the green circle and T-Shirt/Top in the blue circle, while less similar products are merged together at higher LCA, e.g., categories Shirt in the green circle and Trouser in the purple circle, or categories Bag in the orange circle and Trouser in the purple circle." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 415, + 289, + 548 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 415, + 289, + 548 + ], + "spans": [ + { + "bbox": [ + 46, + 415, + 289, + 548 + ], + "type": "text", + "content": "a lot to the final performance. The effectiveness of " + }, + { + "bbox": [ + 46, + 415, + 289, + 548 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{rc}}" + }, + { + "bbox": [ + 46, + 415, + 289, + 548 + ], + "type": "text", + "content": " is relatively less significant. This may be due to the property of experimental datasets. Especially, such datasets e.g., MNIST-USPS, Multi-Fashion, and NR-MNSIT are constructed by picking pairs of individual objects from the corresponding classes of multiple datasets [53, 65, 67]. So consistency may play a much more important role compared with complementarity. As for MHCN with Euclidean AEs, we can find that the performance also degenerates significantly, indicating the effectiveness of hyperbolic embeddings for modeling hierarchies." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "text", + "content": "In addition, to intuitively show the effectiveness of " + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{uni}}" + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "text", + "content": ", taking MNIST-USPS as an example, we train an MHCN model mapping the data to a two-dimensional Poincaré ball with different weights for " + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{uni}}" + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "text", + "content": ". We visualize the averaged embeddings and the decoded clustering trees. For clarity, we present the top-35 non-leaf nodes in Figure 3. As shown, if " + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{uni}}" + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "text", + "content": " is absent, only " + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{align}}" + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "text", + "content": " for multi-view consistency and " + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{rc}}" + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "text", + "content": " for multi-view complementarity will force the embeddings to gather in a small corner of the Poincaré ball, resulting in a skewed tree that lacks interpretability. With the weight of " + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{uni}}" + }, + { + "bbox": [ + 46, + 557, + 287, + 712 + ], + "type": "text", + "content": " growing, the embeddings become more uniformly distributed, and the corresponding clustering trees become more balanced." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 415, + 420, + 428 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 415, + 420, + 428 + ], + "spans": [ + { + "bbox": [ + 306, + 415, + 420, + 428 + ], + "type": "text", + "content": "4.4. Scalability Analysis" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 434, + 545, + 506 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 434, + 545, + 506 + ], + "spans": [ + { + "bbox": [ + 304, + 434, + 545, + 506 + ], + "type": "text", + "content": "As shown in Table 1, the DP results of our method exceed those of other baselines on the large-scale NR-MNIST dataset. Also, Table 3 shows that the running time of our method achieves a significant decline when compared with the classic baselines, i.e., HACs. The theoretical complexity analysis can be found in the appendix." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 513, + 545, + 527 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 513, + 545, + 527 + ], + "spans": [ + { + "bbox": [ + 305, + 513, + 545, + 527 + ], + "type": "text", + "content": "4.5. Inductive Hierarchical Clustering Experiments" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 532, + 545, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 532, + 545, + 628 + ], + "spans": [ + { + "bbox": [ + 304, + 532, + 545, + 628 + ], + "type": "text", + "content": "It is difficult for traditional HAC-based methods to train on one dataset and then predict on another. However, this inductive HC setting becomes relatively easy with MHCN. We train the model with the training set of NR-MNIST, then infer the results with the test set, and finally, the DP result is " + }, + { + "bbox": [ + 304, + 532, + 545, + 628 + ], + "type": "inline_equation", + "content": "96.54\\%" + }, + { + "bbox": [ + 304, + 532, + 545, + 628 + ], + "type": "text", + "content": ". This result is numerically comparable with the result in Table 1 " + }, + { + "bbox": [ + 304, + 532, + 545, + 628 + ], + "type": "inline_equation", + "content": "(98.71\\%)" + }, + { + "bbox": [ + 304, + 532, + 545, + 628 + ], + "type": "text", + "content": ". The ability of inductive HC may help improve the performance, e.g., transfer learning." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 635, + 471, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 635, + 471, + 647 + ], + "spans": [ + { + "bbox": [ + 305, + 635, + 471, + 647 + ], + "type": "text", + "content": "4.6. Parameter Sensitivity Analysis" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 653, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 712 + ], + "type": "text", + "content": "Trade-off efficient " + }, + { + "bbox": [ + 304, + 653, + 545, + 712 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 653, + 545, + 712 + ], + "type": "text", + "content": ". To start with, we focus on the choice of the trade-off efficient " + }, + { + "bbox": [ + 304, + 653, + 545, + 712 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 653, + 545, + 712 + ], + "type": "text", + "content": ". By fixing the other hyperparameters, we investigate how the " + }, + { + "bbox": [ + 304, + 653, + 545, + 712 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 653, + 545, + 712 + ], + "type": "text", + "content": " parameter balances the effects of reconstruction and alignment loss components for multi-view learning. We show the DP result of different" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16532" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 71, + 284, + 194 + ], + "blocks": [ + { + "bbox": [ + 49, + 71, + 284, + 194 + ], + "lines": [ + { + "bbox": [ + 49, + 71, + 284, + 194 + ], + "spans": [ + { + "bbox": [ + 49, + 71, + 284, + 194 + ], + "type": "image", + "image_path": "f8448c59cbb99f670b254d45d552b1bb5b6ba2c93750cd75d7651e35ec40eb86.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 104, + 203, + 230, + 216 + ], + "lines": [ + { + "bbox": [ + 104, + 203, + 230, + 216 + ], + "spans": [ + { + "bbox": [ + 104, + 203, + 230, + 216 + ], + "type": "text", + "content": "Figure 5: " + }, + { + "bbox": [ + 104, + 203, + 230, + 216 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 104, + 203, + 230, + 216 + ], + "type": "text", + "content": " sensitivity analysis" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 236, + 286, + 356 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 236, + 286, + 356 + ], + "spans": [ + { + "bbox": [ + 46, + 236, + 286, + 356 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 236, + 286, + 356 + ], + "type": "text", + "content": " values in a range between 0.0 and 1.0. As shown in Figure 5, with the increase of " + }, + { + "bbox": [ + 46, + 236, + 286, + 356 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 236, + 286, + 356 + ], + "type": "text", + "content": " values, the quality of the final tree structures consistently stabilizes at an optimal level on all datasets. When " + }, + { + "bbox": [ + 46, + 236, + 286, + 356 + ], + "type": "inline_equation", + "content": "\\alpha = 0" + }, + { + "bbox": [ + 46, + 236, + 286, + 356 + ], + "type": "text", + "content": ", the performance of HC gets near the lowest point, especially on MNIST-USPS, BBC-Sport, Multi-Fashion, and NR-MNSIT datasets. The principal reason is that in MHCN, the consistency across all views is achieved via the multi-view alignment loss, which is much essential to capture view-common meaningful semantics and further boost the final clustering trees." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "spans": [ + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "text", + "content": "Temperature parameters " + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{align}}" + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{uni}}" + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "text", + "content": ". Similarly, with the other hyperparameters fixed, we present the DP results on all datasets by varying " + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{align}}" + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{uni}}" + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "text", + "content": " from 0.0 to 5.0. As shown in Figure 6, both " + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{align}}" + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{uni}}" + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "text", + "content": " set to around 1.0 achieve optimal performance on MNIST-USPS, BDGP, BBCSport, Multi-Fashion, and NR-MNIST datasets, while the HC performance on Caltech and COIL-20 datasets are more promising with " + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{align}} = \\tau_{\\mathrm{uni}} = 0.5" + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "text", + "content": ". Besides, the model is more robust to changes of " + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{align}}" + }, + { + "bbox": [ + 46, + 357, + 286, + 464 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 472, + 122, + 484 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 472, + 122, + 484 + ], + "spans": [ + { + "bbox": [ + 47, + 472, + 122, + 484 + ], + "type": "text", + "content": "4.7. Case Study" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 491, + 286, + 646 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 491, + 286, + 646 + ], + "spans": [ + { + "bbox": [ + 46, + 491, + 286, + 646 + ], + "type": "text", + "content": "In addition to quantitative analysis, we qualitatively examine the quality of the final MVHC tree structures learned by our method. We take a truncated sub-tree of the complete Multi-Fashion tree as an example in Figure 4, where more similar leaf nodes are merged together earlier in the tree structure, guaranteeing explicit hierarchical partitioning. We can observe that more similar leaf nodes are merged together earlier in the tree structure, e.g., categories Shirt and T-Shirt/Top, while less similar products are merged together at higher LCA, e.g., categories Shirt and Trouser, or categories Bag and Trouser. Therefore, MHCN is capable of guaranteeing meaningful fine-grained hierarchical partitioning with high interpretability for the multi-view data." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 657, + 202, + 670 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 657, + 202, + 670 + ], + "spans": [ + { + "bbox": [ + 47, + 657, + 202, + 670 + ], + "type": "text", + "content": "5. Conclusion & Future Work" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 677, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 286, + 713 + ], + "type": "text", + "content": "In this work, we present a novel one-stage framework MHCN to solve the multi-view hierarchical clustering problem. With the help of the hyperbolic model of the Poincaré" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 307, + 79, + 426, + 129 + ], + "blocks": [ + { + "bbox": [ + 307, + 79, + 426, + 129 + ], + "lines": [ + { + "bbox": [ + 307, + 79, + 426, + 129 + ], + "spans": [ + { + "bbox": [ + 307, + 79, + 426, + 129 + ], + "type": "image", + "image_path": "2227b53728230b7cf32a6901b571a50b52889213861a2ffffbf4fd30a52d6231.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 338, + 131, + 396, + 140 + ], + "lines": [ + { + "bbox": [ + 338, + 131, + 396, + 140 + ], + "spans": [ + { + "bbox": [ + 338, + 131, + 396, + 140 + ], + "type": "text", + "content": "(a) MNIST-USPS" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 427, + 80, + 545, + 129 + ], + "blocks": [ + { + "bbox": [ + 427, + 80, + 545, + 129 + ], + "lines": [ + { + "bbox": [ + 427, + 80, + 545, + 129 + ], + "spans": [ + { + "bbox": [ + 427, + 80, + 545, + 129 + ], + "type": "image", + "image_path": "230f3dad9f90ed092e7cf5cc83fe5c5bac6b27bc1a088341e5002f9342e2ac67.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 468, + 131, + 503, + 140 + ], + "lines": [ + { + "bbox": [ + 468, + 131, + 503, + 140 + ], + "spans": [ + { + "bbox": [ + 468, + 131, + 503, + 140 + ], + "type": "text", + "content": "(b) BDGP" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 307, + 152, + 427, + 200 + ], + "blocks": [ + { + "bbox": [ + 307, + 152, + 427, + 200 + ], + "lines": [ + { + "bbox": [ + 307, + 152, + 427, + 200 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 427, + 200 + ], + "type": "image", + "image_path": "ceda2cd50902ef1edc37a3444bedfdd9608e1777df74820a9e1c1401bc5cd7b6.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 348, + 202, + 386, + 212 + ], + "lines": [ + { + "bbox": [ + 348, + 202, + 386, + 212 + ], + "spans": [ + { + "bbox": [ + 348, + 202, + 386, + 212 + ], + "type": "text", + "content": "(c) Caltech" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 429, + 152, + 545, + 200 + ], + "blocks": [ + { + "bbox": [ + 429, + 152, + 545, + 200 + ], + "lines": [ + { + "bbox": [ + 429, + 152, + 545, + 200 + ], + "spans": [ + { + "bbox": [ + 429, + 152, + 545, + 200 + ], + "type": "image", + "image_path": "14c79c7887b8928bc55546b9a46c9d9ec100cc04af2d239bd65faba546f9ef7a.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 464, + 201, + 506, + 211 + ], + "lines": [ + { + "bbox": [ + 464, + 201, + 506, + 211 + ], + "spans": [ + { + "bbox": [ + 464, + 201, + 506, + 211 + ], + "type": "text", + "content": "(d) COIL-20" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 307, + 222, + 427, + 270 + ], + "blocks": [ + { + "bbox": [ + 307, + 222, + 427, + 270 + ], + "lines": [ + { + "bbox": [ + 307, + 222, + 427, + 270 + ], + "spans": [ + { + "bbox": [ + 307, + 222, + 427, + 270 + ], + "type": "image", + "image_path": "620ee05bb04673a7ebed7083552168fa3d90c503462abd264c41302b90b1f7ff.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 345, + 273, + 390, + 283 + ], + "lines": [ + { + "bbox": [ + 345, + 273, + 390, + 283 + ], + "spans": [ + { + "bbox": [ + 345, + 273, + 390, + 283 + ], + "type": "text", + "content": "(e) BBCSport" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_caption" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 429, + 223, + 545, + 270 + ], + "blocks": [ + { + "bbox": [ + 429, + 223, + 545, + 270 + ], + "lines": [ + { + "bbox": [ + 429, + 223, + 545, + 270 + ], + "spans": [ + { + "bbox": [ + 429, + 223, + 545, + 270 + ], + "type": "image", + "image_path": "7d03a7770de56127019df89a871dddda191749c90cc50fcbd32d919190dc7e2e.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 457, + 273, + 514, + 282 + ], + "lines": [ + { + "bbox": [ + 457, + 273, + 514, + 282 + ], + "spans": [ + { + "bbox": [ + 457, + 273, + 514, + 282 + ], + "type": "text", + "content": "(f) Multi-Fashion" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 366, + 293, + 486, + 342 + ], + "blocks": [ + { + "bbox": [ + 366, + 293, + 486, + 342 + ], + "lines": [ + { + "bbox": [ + 366, + 293, + 486, + 342 + ], + "spans": [ + { + "bbox": [ + 366, + 293, + 486, + 342 + ], + "type": "image", + "image_path": "37d1ae9f38436c608d377fa1c78d2a750c3c332108af97b89e02ce9907bf536b.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 400, + 344, + 452, + 354 + ], + "lines": [ + { + "bbox": [ + 400, + 344, + 452, + 354 + ], + "spans": [ + { + "bbox": [ + 400, + 344, + 452, + 354 + ], + "type": "text", + "content": "(g) NR-MNIST" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 337, + 364, + 514, + 376 + ], + "lines": [ + { + "bbox": [ + 337, + 364, + 514, + 376 + ], + "spans": [ + { + "bbox": [ + 337, + 364, + 514, + 376 + ], + "type": "text", + "content": "Figure 6: " + }, + { + "bbox": [ + 337, + 364, + 514, + 376 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{align}}" + }, + { + "bbox": [ + 337, + 364, + 514, + 376 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 337, + 364, + 514, + 376 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{uni}}" + }, + { + "bbox": [ + 337, + 364, + 514, + 376 + ], + "type": "text", + "content": " sensitivity analysis" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_caption" + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 399, + 545, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 399, + 545, + 602 + ], + "spans": [ + { + "bbox": [ + 304, + 399, + 545, + 602 + ], + "type": "text", + "content": "ball, we conduct our multi-view representation learning via multiple hyperbolic autoencoders, where the exponential map of each encoder and its inverse logarithm map of each decoder generalize the extracted latent hierarchies to hyperbolic space efficiently. Additionally, we introduce how to promote the final hierarchical clustering tree from the learned hyperbolic representations by jointly optimizing our designed loss functions, including the multi-view alignment loss for view-common information, the reconstruction loss for view-private information, and the hyperbolic uniformity loss for more balanced embedding distribution on the Poincaré ball. Extensive experiments on seven widespread multi-view datasets demonstrate our method achieves state-of-the-art hierarchical clustering performance. In the future, we expect to improve our method with a more general scheme to better learn the different effects of consistency and complementarity of different multi-view datasets." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 306, + 616, + 403, + 629 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 616, + 403, + 629 + ], + "spans": [ + { + "bbox": [ + 306, + 616, + 403, + 629 + ], + "type": "text", + "content": "Acknowledgments" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 304, + 635, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 635, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 635, + 545, + 713 + ], + "type": "text", + "content": "This work was partially supported by the National Key Research and Development Program of China (No. 2018AAA0100204), a key program of fundamental research from Shenzhen Science and Technology Innovation Commission (No. JCYJ20200109113403826), the Major Key Project of PCL (No. 2022ZD0115301), and an Open Research Project of Zhejiang Lab (NO.2022RC0AB04)." + } + ] + } + ], + "index": 25 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16533" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 287, + 709 + ], + "type": "list", + "angle": 0, + "index": 20, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 144 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 144 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 144 + ], + "type": "text", + "content": "[1] MohammadHossein Bateni, Soheil Behnezhad, Mahsa Derakhshan, MohammadTaghi Hajiaghayi, Raimondas Kiveris, Silvio Lattanzi, and Vahab Mirrokni. Affinity clustering: Hierarchical clustering at scale. In NeurIPS, pages 6864-6874, 2017." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 145, + 287, + 177 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 145, + 287, + 177 + ], + "spans": [ + { + "bbox": [ + 53, + 145, + 287, + 177 + ], + "type": "text", + "content": "[2] Eugenio Beltrami. Teoria fondamentale degli spazii di curvatura costante. Annali di Matematica Pura ed Applicata (1867-1897), 2(1):232-255, 1868." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 177, + 287, + 208 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 177, + 287, + 208 + ], + "spans": [ + { + "bbox": [ + 53, + 177, + 287, + 208 + ], + "type": "text", + "content": "[3] Xiao Cai, Feiping Nie, and Heng Huang. Multi-view k-means clustering on big data. In *IJCAI*, pages 2598-2604, 2013." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 209, + 287, + 240 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 209, + 287, + 240 + ], + "spans": [ + { + "bbox": [ + 53, + 209, + 287, + 240 + ], + "type": "text", + "content": "[4] James W Cannon, William J Floyd, Richard Kenyon, Walter R Parry, et al. Hyperbolic geometry. Flavors of geometry, 31(59-115):2, 1997." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 241, + 287, + 283 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 241, + 287, + 283 + ], + "spans": [ + { + "bbox": [ + 53, + 241, + 287, + 283 + ], + "type": "text", + "content": "[5] Ines Chami, Albert Gu, Vaggos Chatziafratis, and Christopher Ré. From trees to continuous embeddings and back: Hyperbolic hierarchical clustering. In NeurIPS, pages 15065-15076, 2020." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 284, + 287, + 316 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 284, + 287, + 316 + ], + "spans": [ + { + "bbox": [ + 53, + 284, + 287, + 316 + ], + "type": "text", + "content": "[6] Ines Chami, Zhitao Ying, Christopher Ré, and Jure Leskovec. Hyperbolic graph convolutional neural networks. In NeurIPS, pages 4869-4880, 2019." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 316, + 287, + 347 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 316, + 287, + 347 + ], + "spans": [ + { + "bbox": [ + 53, + 316, + 287, + 347 + ], + "type": "text", + "content": "[7] Vaggos Chatziafratis, Rad Niazadeh, and Moses Charikar. Hierarchical clustering with structural constraints. In ICML, pages 774-783. PMLR, 2018." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 348, + 287, + 380 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 348, + 287, + 380 + ], + "spans": [ + { + "bbox": [ + 53, + 348, + 287, + 380 + ], + "type": "text", + "content": "[8] Kamalika Chaudhuri, Sham M Kakade, Karen Livescu, and Karthik Sridharan. Multi-view clustering via canonical correlation analysis. In ICML, pages 129-136, 2009." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 380, + 287, + 411 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 380, + 287, + 411 + ], + "spans": [ + { + "bbox": [ + 53, + 380, + 287, + 411 + ], + "type": "text", + "content": "[9] Giovanni Chierchia and Benjamin Perret. Ultrametric fitting by gradient descent. Journal of Statistical Mechanics: Theory and Experiment, 2020(12):124004, 2020." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 412, + 287, + 454 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 412, + 287, + 454 + ], + "spans": [ + { + "bbox": [ + 48, + 412, + 287, + 454 + ], + "type": "text", + "content": "[10] Vincent Cohen-Addad, Varun Kanade, Frederik Mallmann-Trenn, and Claire Mathieu. Hierarchical clustering: Objective functions and algorithms. Journal of the ACM (JACM), 66(4):1-42, 2019." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 455, + 287, + 486 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 455, + 287, + 486 + ], + "spans": [ + { + "bbox": [ + 48, + 455, + 287, + 486 + ], + "type": "text", + "content": "[11] Henry Cohn and Abhinav Kumar. Universally optimal distribution of points on spheres. Journal of the American Mathematical Society, 20(1):99-148, 2007." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 487, + 287, + 517 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 487, + 287, + 517 + ], + "spans": [ + { + "bbox": [ + 48, + 487, + 287, + 517 + ], + "type": "text", + "content": "[12] Shuyang Dai, Zhe Gan, Yu Cheng, Chenyang Tao, Lawrence Carin, and Jingjing Liu. Apo-vae: Text generation in hyperbolic space. arXiv preprint arXiv:2005.00054, 2020." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 518, + 287, + 548 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 518, + 287, + 548 + ], + "spans": [ + { + "bbox": [ + 48, + 518, + 287, + 548 + ], + "type": "text", + "content": "[13] Navneet Dalal and Bill Triggs. Histograms of oriented gradients for human detection. In CVPR, volume 1, pages 886-893. IEEE, 2005." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 549, + 287, + 571 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 549, + 287, + 571 + ], + "spans": [ + { + "bbox": [ + 48, + 549, + 287, + 571 + ], + "type": "text", + "content": "[14] Sanjoy Dasgupta. A cost function for similarity-based hierarchical clustering. In STOC, pages 118-127, 2016." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 571, + 287, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 571, + 287, + 602 + ], + "spans": [ + { + "bbox": [ + 48, + 571, + 287, + 602 + ], + "type": "text", + "content": "[15] Tim R Davidson, Luca Falorsi, Nicola De Cao, Thomas Kipf, and Jakub M Tomczak. Hyperspherical variational autoencoders. arXiv preprint arXiv:1804.00891, 2018." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 602, + 287, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 602, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 48, + 602, + 287, + 635 + ], + "type": "text", + "content": "[16] Delbert Dueck and Brendan J Frey. Non-metric affinity propagation for unsupervised image categorization. In ICCV, pages 1-8, 2007." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 48, + 635, + 287, + 655 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 635, + 287, + 655 + ], + "spans": [ + { + "bbox": [ + 48, + 635, + 287, + 655 + ], + "type": "text", + "content": "[17] Joseph Felsenstein and Joseph Felenstein. Inferring phylogenies, volume 2. Sinauer associates Sunderland, MA, 2004." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 48, + 656, + 287, + 698 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 656, + 287, + 698 + ], + "spans": [ + { + "bbox": [ + 48, + 656, + 287, + 698 + ], + "type": "text", + "content": "[18] Fangxiang Feng, Xiaojie Wang, and Ruifan Li. Cross-modal retrieval with correspondence autoencoder. In Proceedings of the 22nd ACM international conference on Multimedia, pages 7-16, 2014." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 48, + 699, + 287, + 709 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 699, + 287, + 709 + ], + "spans": [ + { + "bbox": [ + 48, + 699, + 287, + 709 + ], + "type": "text", + "content": "[19] Sylvestre Gallot, Dominique Hulin, and Jacques Lafontaine." + } + ] + } + ], + "index": 19 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 74, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 40, + "blocks": [ + { + "bbox": [ + 327, + 74, + 507, + 83 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 74, + 507, + 83 + ], + "spans": [ + { + "bbox": [ + 327, + 74, + 507, + 83 + ], + "type": "text", + "content": "Riemannian geometry, volume 2. Springer, 1990." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 84, + 545, + 105 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 84, + 545, + 105 + ], + "spans": [ + { + "bbox": [ + 307, + 84, + 545, + 105 + ], + "type": "text", + "content": "[20] Octavian Ganea, Gary Bécigneul, and Thomas Hofmann. Hyperbolic neural networks. In NeurIPS, volume 31, 2018." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 105, + 545, + 136 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 105, + 545, + 136 + ], + "spans": [ + { + "bbox": [ + 307, + 105, + 545, + 136 + ], + "type": "text", + "content": "[21] Mina GhadimiAtigh, Julian Schoep, Erman Acar, Nanne van Noord, and Pascal Mettes. Hyperbolic image segmentation. arXiv preprint arXiv:2203.05898, 2022." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 136, + 545, + 168 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 136, + 545, + 168 + ], + "spans": [ + { + "bbox": [ + 307, + 136, + 545, + 168 + ], + "type": "text", + "content": "[22] Zoubin Ghahramani, Michael Jordan, and Ryan P Adams. Tree-structured stick breaking for hierarchical data. In NeurIPS, volume 23, 2010." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 168, + 545, + 212 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 168, + 545, + 212 + ], + "spans": [ + { + "bbox": [ + 307, + 168, + 545, + 212 + ], + "type": "text", + "content": "[23] Kamran Ghasedi Dizaji, Amirhossein Herandi, Cheng Deng, Weidong Cai, and Heng Huang. Deep clustering via joint convolutional autoencoder embedding and relative entropy minimization. In ICCV, pages 5736-5745, 2017." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 212, + 545, + 254 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 212, + 545, + 254 + ], + "spans": [ + { + "bbox": [ + 307, + 212, + 545, + 254 + ], + "type": "text", + "content": "[24] Prasoon Goyal, Zhiting Hu, Xiaodan Liang, Chenyu Wang, and Eric P Xing. Nonparametric variational auto-encoders for hierarchical representation learning. In ICCV, pages 5094–5102, 2017." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 255, + 545, + 275 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 255, + 545, + 275 + ], + "spans": [ + { + "bbox": [ + 307, + 255, + 545, + 275 + ], + "type": "text", + "content": "[25] Katherine A Heller and Zoubin Ghahramani. Bayesian hierarchical clustering. In ICML, pages 297-304, 2005." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 275, + 545, + 318 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 275, + 545, + 318 + ], + "spans": [ + { + "bbox": [ + 307, + 275, + 545, + 318 + ], + "type": "text", + "content": "[26] Joy Hsu, Jeffrey Gu, Gong Wu, Wah Chiu, and Serena Yeung. Capturing implicit hierarchical structure in 3d biomedical images with self-supervised hyperbolic representations. In NeurIPS, pages 5112-5123, 2021." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 318, + 545, + 371 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 318, + 545, + 371 + ], + "spans": [ + { + "bbox": [ + 307, + 318, + 545, + 371 + ], + "type": "text", + "content": "[27] Shudong Huang, Yixi Liu, Yazhou Ren, Ivor W Tsang, Zenglin Xu, and Jiancheng Lv. Learning smooth representation for multi-view subspace clustering. In Proceedings of the 30th ACM International Conference on Multimedia, pages 3421-3429, 2022." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 372, + 545, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 372, + 545, + 403 + ], + "spans": [ + { + "bbox": [ + 307, + 372, + 545, + 403 + ], + "type": "text", + "content": "[28] Anil K Jain, M Narasimha Murty, and Patrick J Flynn. Data clustering: a review. ACM computing surveys (CSUR), 31(3):264-323, 1999." + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 307, + 403, + 545, + 435 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 403, + 545, + 435 + ], + "spans": [ + { + "bbox": [ + 307, + 403, + 545, + 435 + ], + "type": "text", + "content": "[29] Yangbangyan Jiang, Qianqian Xu, Zhiyong Yang, Xiaochun Cao, and Qingming Huang. Dm2c: Deep mixed-modal clustering. In NeurIPS, pages 5880-5890, 2019." + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 307, + 435, + 545, + 479 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 435, + 545, + 479 + ], + "spans": [ + { + "bbox": [ + 307, + 435, + 545, + 479 + ], + "type": "text", + "content": "[30] Zhao Kang, Guoxin Shi, Shudong Huang, Wenyu Chen, Xiaorong Pu, Joey Tianyi Zhou, and Zenglin Xu. Multi-graph fusion for multi-view spectral clustering. Knowledge-Based Systems, 189:105102, 2020." + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 307, + 479, + 545, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 479, + 545, + 510 + ], + "spans": [ + { + "bbox": [ + 307, + 479, + 545, + 510 + ], + "type": "text", + "content": "[31] Ari Kobren, Nicholas Monath, Akshay Krishnamurthy, and Andrew McCallum. A hierarchical algorithm for extreme clustering. In KDD, pages 255-264, 2017." + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 307, + 510, + 545, + 532 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 510, + 545, + 532 + ], + "spans": [ + { + "bbox": [ + 307, + 510, + 545, + 532 + ], + "type": "text", + "content": "[32] John M Lee. Smooth manifolds. In Introduction to Smooth Manifolds, pages 1-31. Springer, 2013." + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 307, + 532, + 545, + 573 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 532, + 545, + 573 + ], + "spans": [ + { + "bbox": [ + 307, + 532, + 545, + 573 + ], + "type": "text", + "content": "[33] Ruihuang Li, Changqing Zhang, Huazhu Fu, Xi Peng, Tianyi Zhou, and Qinghua Hu. Reciprocal multi-layer subspace learning for multi-view clustering. In ICCV, pages 8172-8180, 2019." + } + ] + } + ], + "index": 35 + }, + { + "bbox": [ + 307, + 573, + 545, + 605 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 573, + 545, + 605 + ], + "spans": [ + { + "bbox": [ + 307, + 573, + 545, + 605 + ], + "type": "text", + "content": "[34] Yingming Li, Ming Yang, and Zhongfei Zhang. A survey of multi-view representation learning. TKDE, 31(10):1863-1883, 2018." + } + ] + } + ], + "index": 36 + }, + { + "bbox": [ + 307, + 605, + 545, + 637 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 605, + 545, + 637 + ], + "spans": [ + { + "bbox": [ + 307, + 605, + 545, + 637 + ], + "type": "text", + "content": "[35] Zhaoyang Li, Qianqian Wang, Zhiqiang Tao, Quanxue Gao, and Zhaohua Yang. Deep adversarial multi-view clustering network. In IJCAI, pages 2952-2958, 2019." + } + ] + } + ], + "index": 37 + }, + { + "bbox": [ + 307, + 637, + 545, + 680 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 637, + 545, + 680 + ], + "spans": [ + { + "bbox": [ + 307, + 637, + 545, + 680 + ], + "type": "text", + "content": "[36] Dongdong Lin, Jigang Zhang, Jingyao Li, Chao Xu, Hong-Wen Deng, and Yu-Ping Wang. An integrative imputation method based on multi-omics datasets. BMC bioinformatics, 17(1):1-12, 2016." + } + ] + } + ], + "index": 38 + }, + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "type": "text", + "content": "[37] Fangfei Lin, Bing Bai, Kun Bai, Yazhou Ren, Peng Zhao, and Zenglin Xu. Contrastive multi-view hyperbolic hierarchical clustering. In IJCAI, pages 3250-3256, 2022." + } + ] + } + ], + "index": 39 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "text", + "content": "16534" + } + ] + } + ], + "index": 41 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 703 + ], + "type": "list", + "angle": 0, + "index": 18, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[38] Bulou Liu, Bing Bai, Weibang Xie, Yiwen Guo, and Hao Chen. Task-optimized user clustering based on mobile app usage for cold-start recommendations. In KDD, pages 3347–3356, 2022." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 116, + 287, + 159 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 116, + 287, + 159 + ], + "spans": [ + { + "bbox": [ + 48, + 116, + 287, + 159 + ], + "type": "text", + "content": "[39] Jiyuan Liu, Xinwang Liu, Yuexiang Yang, Li Liu, Siqi Wang, Weixuan Liang, and Jiangyong Shi. One-pass multi-view clustering for large-scale data. In ICCV, pages 12344-12353, 2021." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 159, + 287, + 191 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 159, + 287, + 191 + ], + "spans": [ + { + "bbox": [ + 48, + 159, + 287, + 191 + ], + "type": "text", + "content": "[40] Weiyang Liu, Rongmei Lin, Zhen Liu, Lixin Liu, Zhiding Yu, Bo Dai, and Le Song. Learning towards minimum hyperspherical energy. In NeurIPS, volume 31, 2018." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 191, + 287, + 223 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 191, + 287, + 223 + ], + "spans": [ + { + "bbox": [ + 48, + 191, + 287, + 223 + ], + "type": "text", + "content": "[41] Shirui Luo, Changqing Zhang, Wei Zhang, and Xiaochun Cao. Consistent and specific multi-view subspace clustering. In AAAI, pages 3730-3737, 2018." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 223, + 287, + 266 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 223, + 287, + 266 + ], + "spans": [ + { + "bbox": [ + 48, + 223, + 287, + 266 + ], + "type": "text", + "content": "[42] Emile Mathieu, Charline Le Lan, Chris J Maddison, Ryota Tomioka, and Yee Whye Teh. Continuous hierarchical representations with poincaré variational auto-encoders. In NeurIPS, volume 32, 2019." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 266, + 287, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 266, + 287, + 308 + ], + "spans": [ + { + "bbox": [ + 48, + 266, + 287, + 308 + ], + "type": "text", + "content": "[43] Nicholas Monath, Manzil Zaheer, Daniel Silva, Andrew McCallum, and Amr Ahmed. Gradient-based hierarchical clustering using continuous representations of trees in hyperbolic space. In KDD, pages 714-722, 2019." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 309, + 287, + 350 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 309, + 287, + 350 + ], + "spans": [ + { + "bbox": [ + 48, + 309, + 287, + 350 + ], + "type": "text", + "content": "[44] Fionn Murtagh and Pedro Contreras. Algorithms for hierarchical clustering: an overview. Wiley Interdisciplinary Reviews: Data Mining and Knowledge Discovery, 2(1):86-97, 2012." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 351, + 287, + 394 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 351, + 287, + 394 + ], + "spans": [ + { + "bbox": [ + 48, + 351, + 287, + 394 + ], + "type": "text", + "content": "[45] Yoshihiro Nagano, Shoichiro Yamaguchi, Yasuhiro Fujita, and Masanori Koyama. A differentiable gaussian-like distribution on hyperbolic space for gradient-based learning. CoRR, abs/1902.02992, 2019." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 395, + 287, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 395, + 287, + 426 + ], + "spans": [ + { + "bbox": [ + 48, + 395, + 287, + 426 + ], + "type": "text", + "content": "[46] Stanislav Naumov, Grigory Yaroslavl'tsev, and Dmitrii Avdiukhin. Objective-based hierarchical clustering of deep embedding vectors. In AAAI, pages 9055-9063, 2021." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 426, + 287, + 458 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 426, + 287, + 458 + ], + "spans": [ + { + "bbox": [ + 48, + 426, + 287, + 458 + ], + "type": "text", + "content": "[47] Maximillian Nickel and Douwe Kiela. Poincaré embeddings for learning hierarchical representations. In NeurIPS, pages 6338-6347, 2017." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 458, + 287, + 500 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 458, + 287, + 500 + ], + "spans": [ + { + "bbox": [ + 48, + 458, + 287, + 500 + ], + "type": "text", + "content": "[48] Aude Oliva and Antonio Torralba. Modeling the shape of the scene: A holistic representation of the spatial envelope. International journal of computer vision, 42(3):145-175, 2001." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 501, + 287, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 501, + 287, + 521 + ], + "spans": [ + { + "bbox": [ + 48, + 501, + 287, + 521 + ], + "type": "text", + "content": "[49] Erlin Pan and Zhao Kang. Multi-view contrastive graph clustering. In NeurIPS, volume 34, 2021." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 522, + 287, + 564 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 522, + 287, + 564 + ], + "spans": [ + { + "bbox": [ + 48, + 522, + 287, + 564 + ], + "type": "text", + "content": "[50] Jiwoong Park, Junho Cho, Hyung Jin Chang, and Jin Young Choi. Unsupervised hyperbolic representation learning via message passing auto-encoders. In CVPR, pages 5516–5526, 2021." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 565, + 287, + 608 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 565, + 287, + 608 + ], + "spans": [ + { + "bbox": [ + 48, + 565, + 287, + 608 + ], + "type": "text", + "content": "[51] Sakshi Patel, Shivani Sihmar, and Aman Jatain. A study of hierarchical clustering algorithms. In 2015 2nd international conference on computing for sustainable global development (INDIACom), pages 537-541. IEEE, 2015." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 608, + 287, + 640 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 608, + 287, + 640 + ], + "spans": [ + { + "bbox": [ + 48, + 608, + 287, + 640 + ], + "type": "text", + "content": "[52] Wei Peng, Tuomas Varanka, Abdelrahman Mostafa, Henglin Shi, and Guoying Zhao. Hyperbolic deep neural networks: A survey. arXiv preprint arXiv:2101.04562, 2021." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 640, + 287, + 672 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 640, + 287, + 672 + ], + "spans": [ + { + "bbox": [ + 48, + 640, + 287, + 672 + ], + "type": "text", + "content": "[53] Xi Peng, Zhenyu Huang, Jiancheng Lv, Hongyuan Zhu, and Joey Tianyi Zhou. Comic: Multi-view clustering without parameter selection. In ICML, pages 5092-5101, 2019." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 672, + 287, + 692 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 672, + 287, + 692 + ], + "spans": [ + { + "bbox": [ + 48, + 672, + 287, + 692 + ], + "type": "text", + "content": "[54] Peter Petersen. Riemannian geometry, volume 171. Springer, 2006." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 48, + 692, + 287, + 703 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 692, + 287, + 703 + ], + "spans": [ + { + "bbox": [ + 48, + 692, + 287, + 703 + ], + "type": "text", + "content": "[55] Ryohei Shimizu, Yusuke Mukuta, and Tatsuya Harada." + } + ] + } + ], + "index": 17 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 552 + ], + "type": "list", + "angle": 0, + "index": 33, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "text", + "content": "Hyperbolic neural networks++. arXiv preprint arXiv:2006.08210, 2020." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 95, + 545, + 125 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 95, + 545, + 125 + ], + "spans": [ + { + "bbox": [ + 308, + 95, + 545, + 125 + ], + "type": "text", + "content": "[56] Su-Jin Shin, Kyungwoo Song, and Il-Chul Moon. Hierarchically clustered representation learning. In AAAI, pages 5776-5783, 2020." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 126, + 545, + 168 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 126, + 545, + 168 + ], + "spans": [ + { + "bbox": [ + 307, + 126, + 545, + 168 + ], + "type": "text", + "content": "[57] Huayi Tang and Yong Liu. Deep safe incomplete multi-view clustering: Theorem and algorithm. In International Conference on Machine Learning, pages 21090-21110. PMLR, 2022." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 169, + 545, + 201 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 169, + 545, + 201 + ], + "spans": [ + { + "bbox": [ + 307, + 169, + 545, + 201 + ], + "type": "text", + "content": "[58] Yee Teh, Hal Daume III, and Daniel M Roy. Bayesian agglomerative clustering with coalescents. In NeurIPS, volume 20, 2007." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 201, + 545, + 233 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 201, + 545, + 233 + ], + "spans": [ + { + "bbox": [ + 307, + 201, + 545, + 233 + ], + "type": "text", + "content": "[59] Daniel J Trosten, Sigurd Lokse, Robert Jenssen, and Michael Kampffmeyer. Reconsidering representation alignment for multi-view clustering. In CVPR, pages 1255-1265, 2021." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 233, + 545, + 264 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 233, + 545, + 264 + ], + "spans": [ + { + "bbox": [ + 307, + 233, + 545, + 264 + ], + "type": "text", + "content": "[60] Abraham Albert Ungar. A gyrovector space approach to hyperbolic geometry. Synthesis Lectures on Mathematics and Statistics, 1(1):1-194, 2008." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 264, + 545, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 264, + 545, + 297 + ], + "spans": [ + { + "bbox": [ + 307, + 264, + 545, + 297 + ], + "type": "text", + "content": "[61] Dingkang Wang and Yusu Wang. An improved cost function for hierarchical cluster trees. Journal of Computational Geometry, 11(1):283-331, 2020." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 297, + 545, + 329 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 297, + 545, + 329 + ], + "spans": [ + { + "bbox": [ + 307, + 297, + 545, + 329 + ], + "type": "text", + "content": "[62] Tongzhou Wang and Phillip Isola. Understanding contrastive representation learning through alignment and uniformity on the hypersphere. In ICML, pages 9929-9939. PMLR, 2020." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 329, + 545, + 361 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 329, + 545, + 361 + ], + "spans": [ + { + "bbox": [ + 307, + 329, + 545, + 361 + ], + "type": "text", + "content": "[63] Weiran Wang, Raman Arora, Karen Livescu, and Jeff Bilmes. On deep multi-view representation learning. In ICML, pages 1083-1092, 2015." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 361, + 545, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 361, + 545, + 392 + ], + "spans": [ + { + "bbox": [ + 307, + 361, + 545, + 392 + ], + "type": "text", + "content": "[64] Junyuan Xie, Ross Girshick, and Ali Farhadi. Unsupervised deep embedding for clustering analysis. In ICML, pages 478-487. PMLR, 2016." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 392, + 545, + 434 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 392, + 545, + 434 + ], + "spans": [ + { + "bbox": [ + 307, + 392, + 545, + 434 + ], + "type": "text", + "content": "[65] Jie Xu, Yazhou Ren, Guofeng Li, Lili Pan, Ce Zhu, and Zenglin Xu. Deep embedded multi-view clustering with collaborative training. Information Sciences, pages 279-290, 2021." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 435, + 545, + 488 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 435, + 545, + 488 + ], + "spans": [ + { + "bbox": [ + 307, + 435, + 545, + 488 + ], + "type": "text", + "content": "[66] Jie Xu, Yazhou Ren, Huayi Tang, Xiaorong Pu, Xiaofeng Zhu, Ming Zeng, and Lifang He. Multi-vae: Learning disentangled view-common and view-peculiar visual representations for multi-view clustering. In ICCV, pages 9234–9243, 2021." + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 307, + 489, + 545, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 489, + 545, + 521 + ], + "spans": [ + { + "bbox": [ + 307, + 489, + 545, + 521 + ], + "type": "text", + "content": "[67] Jie Xu, Huayi Tang, Yazhou Ren, Liang Peng, Xiaofeng Zhu, and Lifang He. Multi-level feature learning for contrastive multi-view clustering. In CVPR, pages 16051-16060, 2022." + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 307, + 521, + 545, + 552 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 521, + 545, + 552 + ], + "spans": [ + { + "bbox": [ + 307, + 521, + 545, + 552 + ], + "type": "text", + "content": "[68] Qinghai Zheng, Jihua Zhu, and Shuangxun Ma. Multi-view hierarchical clustering. arXiv preprint arXiv:2010.07573, 2020." + } + ] + } + ], + "index": 32 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "16535" + } + ] + } + ], + "index": 34 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/f9c54455-f324-48c7-9865-4e8d15caf336_content_list.json b/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/f9c54455-f324-48c7-9865-4e8d15caf336_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..94be9e5eefe7c7dccd93ba16d90ae74de0f6a6f0 --- /dev/null +++ b/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/f9c54455-f324-48c7-9865-4e8d15caf336_content_list.json @@ -0,0 +1,1934 @@ +[ + { + "type": "text", + "text": "MHEntropy: Entropy Meets Multiple Hypotheses for Pose and Shape Recovery", + "text_level": 1, + "bbox": [ + 84, + 130, + 883, + 154 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Rongyu Chen* Linlin Yang* Angela Yao National University of Singapore {rchen, yangll, ayao}@comp.nus.edu.sg", + "bbox": [ + 290, + 180, + 679, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 268, + 313, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "For monocular RGB-based 3D pose and shape estimation, multiple solutions are often feasible due to factors like occlusions and truncations. This work presents a multi-hypothesis probabilistic framework by optimizing the Kullback-Leibler divergence (KLD) between the data and model distribution. Our formulation reveals a connection between the pose entropy and diversity in the multiple hypotheses that has been neglected by previous works. For a comprehensive evaluation, besides the best hypothesis (BH) metric, we factor in visibility for evaluating diversity. Additionally, our framework is label-friendly - it can be learned from only partial 2D keypoints, such as visible keypoints. Experiments on both ambiguous and real-world benchmarks demonstrate that our method outperforms other state-of-the-art multi-hypothesis methods. The project page is at https://gloryyrolg.github.io/MHEntropy.", + "bbox": [ + 75, + 301, + 473, + 544 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 574, + 209, + 589 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Pose and shape estimation is a core component of augmented and virtual reality applications. The majority of monocular 3D pose and shape estimation approaches [28, 31, 7, 3, 15] are designed to predict only a single solution, yet 3D recovery from a monocular input is an inverse problem. Multiple solutions are feasible, especially under settings with occlusions, truncations, low image quality, or other ambiguities. It is therefore meaningful and desirable to make multi-hypothesis predictions. Multiple hypotheses are also useful in downstream tasks such as 2D keypoint fitting [21] and multi-view fusion [21, 25].", + "bbox": [ + 75, + 601, + 468, + 767 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Previous multi-hypothesis works use various 2D [2, 21, 37], 3D [39, 25, 2, 21, 37, 35], and mesh [2] reconstruction losses to facilitate kinematically feasible poses and shapes, while encouraging diversity in the solution set. Yet the learning and evaluation for multi-hypothesis works are underdeveloped. Learning-wise, many existing works are not label-friendly and often require one-to-many labeled data to", + "bbox": [ + 75, + 768, + 470, + 875 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/258c6c837eb60aac6fbe5c41b5378260feca4df7befe2ec9f66624b76f27cc1b.jpg", + "image_caption": [ + "(a) Occluded Input" + ], + "image_footnote": [], + "bbox": [ + 545, + 273, + 671, + 371 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/333fac67ee15126e3d89ff441679c070e2c844b5f93798fd24154b4e88bc8f48.jpg", + "image_caption": [ + "(b) Visible versus Occluded" + ], + "image_footnote": [], + "bbox": [ + 692, + 284, + 833, + 364 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/f6f069c6c20abddaac054f456da55cb3c4a9d3a879f2bb39c37ce72917605888.jpg", + "image_caption": [ + "(c) Multiple Hypotheses" + ], + "image_footnote": [], + "bbox": [ + 557, + 400, + 645, + 464 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/3721891385bd9b692eae5fb57fc66a60231ff5dd1da61fa597d46d659d2ce8cf.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 653, + 398, + 728, + 467 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/c554c1e2bff2722f9ba37fef492874895dca1bcbb34e5bd6c7bb07446292ef06.jpg", + "image_caption": [ + "Figure 1. Our method estimates diverse and feasible hypotheses for occluded joints while preserving accuracy for visible joints." + ], + "image_footnote": [], + "bbox": [ + 738, + 398, + 839, + 468 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "achieve diversity [21, 2, 35, 25], i.e., similar ambiguous observations with multiple distinct ground-truth poses. Such labels are challenging to obtain, especially under occlusion or out-of-view scenarios for which multi-hypothesis predictions are the most meaningful. While empirical efforts have been made to avoid mode collapse while encouraging diversity [26, 27], these methods often do not fully explore the solution space. It is, therefore, non-trivial to achieve feasible and as diverse as possible solutions.", + "bbox": [ + 496, + 549, + 892, + 685 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Evaluation-wise, multi-hypothesis works use the best hypothesis (BH) as the metric of choice [25, 2, 21, 37, 26]. BH measures the closest distance between a hypothesis set and the ground truth. It emphasizes the accuracy of the closest hypothesis while ignoring the set holistically. Few works explicitly and quantitatively evaluate the diversity of the predicted hypotheses. When they do so, diversity is evaluated independently from the input [26]. Yet joints under occlusion or a lack of evidence feature more uncertainty, and as such should correspond to more diversity, while joints should be less diverse on unambiguous parts. Current multi-hypothesis evaluation schemes do not make such distinctions. Unwanted diversity on unambiguous joints also contributes to the calculation of overall diversity.", + "bbox": [ + 496, + 689, + 893, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Equal contribution.", + "bbox": [ + 94, + 887, + 205, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "14840", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "This paper addresses these shortcomings and presents a new multi-hypothesis framework for estimating 3D poses and shapes. At the heart of our method is a simple yet essential underlying criterion - hypotheses should be diverse, but meaningfully so, and correlate with an observation's ambiguity (see Fig. 1 (b)). To that end, we take a probabilistically principled approach and minimize the Kullback-Leibler (KL) divergence between the model distribution and the underlying data distribution. Our objective results in three terms: a reconstruction accuracy, a pose prior, and most interestingly, a model entropy term. This additional entropy term echoes the principle of maximum entropy [10], where the probability distribution is designed to align with observations but otherwise be as unbiased as possible. For pose estimation, this means that visible and unambiguous keypoints should remain fixed across the hypotheses, while occluded and ambiguous keypoints should be feasible yet diverse (see Fig. 1 (b) and (c)).", + "bbox": [ + 76, + 90, + 472, + 363 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Unlike existing works [35, 25, 21], our formulation for diversity does not require one-to-many training data. Instead, our model is trained by explicitly encouraging it to explore the feasible solution space via entropy maximization while remaining consistent with the evidence. For the implementation of our framework, we learn a conditional distribution of parameters with a normalizing flow model. The parameters modelled come from parametric 3D models like MANO [33] and SMPL [30].", + "bbox": [ + 76, + 363, + 472, + 498 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To be label-friendly, we advocate using weak labels; specifically, we recommend 2D keypoints from only visible joints. Using 2D keypoint labels is well established in the literature [3, 22]. However, considering only visible 2D keypoints is not well-studied, even though it is highly intuitive from an annotation point of view and a natural fit for multiple hypotheses.", + "bbox": [ + 76, + 500, + 472, + 604 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "For a comprehensive evaluation beyond the best hypothesis we introduce a Per-Joint Diversity (PJD) to measure the diversity of visible and occluded keypoints. Based on PJD, we further propose a Relative Diversity (RD) ratio to measure the reasonable diversity of the hypotheses. A low ratio indicates that observed keypoints are deterministic while occluded keypoints are diverse. In experiments, our method finds highly accurate BH and achieves the best RD ratio compared to other multi-hypothesis approaches. To summarize our contributions,", + "bbox": [ + 76, + 604, + 472, + 755 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We formulate multi-hypothesis estimation as a minimization of the KL divergence between the model distribution and the data distribution. This formulation is probabilistically principled and naturally yields an entropy term that encourages diversity in the solution set.", + "- From our KL formulation, we propose a framework to estimate multiple hypotheses of 3D pose and shape that favours feasible and diverse solutions by design." + ], + "bbox": [ + 96, + 768, + 468, + 900 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We emphasize visibility in multi-hypothesis frameworks by exploring visible 2D keypoints, i.e. partial weak labels for estimating 3D pose and shape and factoring in visibility for evaluating diversity.", + "- Experiments on toy, ambiguous, and real-world data demonstrate that our method achieves excellent diversity and the best BH compared to other state-of-the-art multi-hypothesis methods." + ], + "bbox": [ + 517, + 90, + 893, + 228 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 248, + 640, + 263 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. 3D Human/Hand Pose & Shape Recovery", + "text_level": 1, + "bbox": [ + 500, + 273, + 854, + 291 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Existing works estimate 3D pose and shape either directly [3, 16, 20, 19], or indirectly [5, 28, 31] via a parametric model like SMPL and MANO. Parametric models serve as priors to encourage feasible solutions [3, 16] and reduce the reliance on labels [22, 41]. The parameters of parametric models are typically learned under the supervision of 3D meshes and poses [3, 16, 20, 19]. Without parametric models, works like [42, 5, 28, 31, 22] focus on the representations of 3D surfaces and the design of architectures. They convert the surfaces into different 3D representations like mesh vertices [31, 28], UV mapping [42, 5, 40], and implicit representations [6], and then fit the surfaces based on architectures like GCNs [22] and Transformers [28].", + "bbox": [ + 496, + 299, + 893, + 496 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. Multi-Hypothesis Methods", + "text_level": 1, + "bbox": [ + 500, + 508, + 741, + 526 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "These methods predict diverse and feasible predictions from ambiguous input evidence, often via deep generative models. The work in [35] proposes a conditional VAE to model the distribution of a 3D pose sample set that is consistent with the 2D pose, which helps to tackle the inherent ambiguity in 2D-to-3D lifting. MDN-based works [39, 25] introduce mixture density models to estimate multiple hypotheses by minimizing the negative log-likelihood of a multi-modal mixture of Gaussians.", + "bbox": [ + 496, + 534, + 893, + 671 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "More recent works [37, 2, 21] apply normalizing flow (NF) models. The work in [2] directly employs NFs as a prior on the distribution of plausible poses at test time. Differently, other works, like [37, 21], propose using a conditional NF. Specifically, [21] uses the conditional NF to model the distribution of SMPL pose parameters conditioned on the 2D image, while [37] adopts predicted 2D keypoints as a condition for the NF and specifically considers 2D poses in the latent space to model the distribution from 3D poses to 2D poses and its reverse.", + "bbox": [ + 496, + 672, + 893, + 823 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Despite their use of probabilistic modeling, few existing works use explicit distributional optimization objectives. Our proposed method is derived directly from KL divergence, which also brings an entropy term and explicitly encourages the estimation of multiple hypotheses.", + "bbox": [ + 496, + 825, + 893, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "14841", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "3. Preliminaries", + "text_level": 1, + "bbox": [ + 76, + 89, + 217, + 104 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Overview of Parametric Models", + "text_level": 1, + "bbox": [ + 76, + 138, + 359, + 154 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "MANO [33] and SMPL [30] are commonly-used parametric 3D models for human hands and bodies with pose parameters $\\theta \\in \\mathbb{R}^{N_{\\theta}}$ and shape parameters $\\beta \\in \\mathbb{R}^{N_{\\beta}}$ . Usually, $\\theta$ and $\\beta$ are expressed as axis-angle rotations and PCA coefficients learned from pose data and registered shapes, respectively, though $\\theta$ can also be expressed as PCA coefficients for MANO. Together, $\\theta$ and $\\beta$ fully determine the surface mesh $\\mathcal{M}(\\theta ,\\beta)\\in \\mathbb{R}^{N_m\\times 3}$ and joint coordinates $\\mathcal{J}(\\theta ,\\beta)\\in \\mathbb{R}^{N_j\\times 3}$ in the 3D space.", + "bbox": [ + 75, + 161, + 468, + 297 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Given camera parameters $\\mathbf{c} = \\{R, \\mathbf{t}, s\\}$ , where $R \\in \\mathbb{R}^{3 \\times 3}$ is a global rotation matrix, $\\mathbf{t} \\in \\mathbb{R}^2$ is the translation, and $s$ is a scaling factor, the 3D pose $\\mathcal{J}(\\theta, \\beta)$ can be projected into 2D joints $\\mathbf{j}$ with an orthographic projection $\\Pi$ :", + "bbox": [ + 76, + 297, + 470, + 359 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {j} = s \\cdot \\Pi (R \\cdot \\mathcal {J} (\\theta , \\beta)) + \\mathbf {t}. \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 176, + 368, + 468, + 385 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. 2D Keypoint Supervision", + "text_level": 1, + "bbox": [ + 76, + 393, + 305, + 409 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "One weakly-supervised variant of monocular 3D pose and shape estimation is learned from only 2D keypoint annotations. A common approach [3] is to estimate the MANO or SMPL parameters $(\\hat{\\theta},\\hat{\\beta})$ for a given image and project the resulting 3D pose back into 2D joints $\\hat{\\mathbf{j}}$ , as per Eq. (1). The parameters can be learned with ground-truth 2D joints $\\mathbf{j}$ by minimizing the following objective:", + "bbox": [ + 75, + 416, + 468, + 525 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} = \\left\\| \\mathbf {j} - \\hat {\\mathbf {j}} \\right\\| _ {1} + \\lambda_ {\\theta} \\mathcal {R} (\\hat {\\theta}) + \\lambda_ {\\beta} \\| \\hat {\\beta} \\| _ {2} ^ {2}, \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 150, + 531, + 468, + 551 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "featuring a 2D reconstruction loss, a prior term $\\mathcal{R}(\\cdot)$ on $\\theta$ to encourage feasible poses, an $l_{2}$ regularization on $\\beta$ , and weighting hyperparameters $\\lambda_{\\theta}$ and $\\lambda_{\\beta}$ . The pose prior $\\mathcal{R}(\\cdot)$ could be adversarial prior for rotation representations [16] or an $l_{2}$ regularization for PCA coefficients [33].", + "bbox": [ + 75, + 559, + 468, + 636 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.3. Normalizing Flow", + "text_level": 1, + "bbox": [ + 76, + 643, + 253, + 660 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Normalizing Flows [32] are generative models with strong modeling capacity for complex, multi-modal distributions. Let $\\mathbf{X}$ denote a $d$ -dimensional random variable under distribution $P(\\mathbf{X})$ . The normalizing flow model represents $\\mathbf{X}$ as a series of invertible mappings $\\{f_l\\}_{l=1}^L: \\mathbb{R}^d \\mapsto \\mathbb{R}^d$ on $d$ -dimensional random variable $\\mathbf{Z}$ :", + "bbox": [ + 75, + 666, + 468, + 756 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {X} = \\mathcal {F} (\\mathbf {Z}) = f _ {L} \\circ \\dots \\circ f _ {2} \\circ f _ {1} (\\mathbf {Z}). \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 153, + 766, + 468, + 784 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Typically, the base distribution $P(\\mathbf{Z})$ is simple, e.g., a normal distribution $\\mathcal{N}(\\mathbf{0},\\mathbf{I})$ . By some specially designed structures of flow blocks [8] and the change-of-variable rule [8], we can get the log-probability density of $\\mathbf{X}$ as:", + "bbox": [ + 75, + 792, + 468, + 853 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\log P (\\mathbf {X}) = \\log P (\\mathbf {Z}) - \\sum_ {l = 1} ^ {L} \\log \\left| \\det \\frac {\\partial f _ {l}}{\\partial \\mathbf {Z} _ {l - 1}} \\right|, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 114, + 862, + 468, + 904 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where, $\\mathbf{Z}_l = f_l(\\mathbf{Z}_{l-1}), \\mathbf{Z}_0 = \\mathbf{Z}$ and $\\mathbf{Z}_L = \\mathbf{X}$ . Normalizing flows estimate the likelihood with the reverse flow $\\mathcal{F}^{-1}(\\mathbf{X})$ transforming $\\mathbf{X}$ to $\\mathbf{Z}$ . For sampling, it first samples $\\mathbf{z}$ from $P(\\mathbf{Z})$ , and passes $\\mathbf{z}$ through the flow $\\mathcal{F}$ to get $\\mathbf{x}$ . Normalizing flows are favoured as generative models because they can tractably estimate the exact likelihood and be optimized through Maximum Likelihood Estimation (MLE). Furthermore, they can also be optimized by sampling through the Law of the Unconscious Statistician (LOTUS).", + "bbox": [ + 498, + 90, + 890, + 227 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.4. Principle of Maximum Entropy", + "text_level": 1, + "bbox": [ + 500, + 238, + 777, + 256 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The entropy of random variable $\\mathbf{X}$ taking values in $\\mathcal{X}$ , $H(\\mathbf{X})$ , quantifies the uncertainty of $\\mathbf{X}$ . It is defined as:", + "bbox": [ + 500, + 262, + 890, + 294 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nH (\\mathbf {X}) = - \\int_ {\\mathcal {X}} p (\\mathbf {x}) \\log p (\\mathbf {x}) d \\mathbf {x}. \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 584, + 306, + 890, + 339 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Methods such as heuristic objectives [26] and mutual information [13, 23] have been proposed to estimate and optimize entropy.", + "bbox": [ + 498, + 349, + 890, + 395 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Under the principle of maximum entropy [10], the probability distribution that most accurately reflects the current state of the system is the one with the highest entropy. In the context of 3D pose and shape estimation, the distribution should be compatible with complete observations, i.e. visible joints, but otherwise be as unbiased as possible for incomplete or ambiguous observations to maximize the entropy. This prevents unnecessary information from being assumed inadvertently. Especially, entropy maximization has garnered significant attention on efficient learning e.g., self-supervised learning [1, 29] and semi-supervised learning [24]. It is used to remove inadvertent assumptions and encourage the model to explore the full set of prototypes.", + "bbox": [ + 498, + 396, + 892, + 593 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4. Methodology", + "text_level": 1, + "bbox": [ + 500, + 608, + 635, + 626 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4.1. Framework", + "text_level": 1, + "bbox": [ + 500, + 633, + 627, + 648 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We target multi-hypothesis 3D pose and shape recovery from RGB inputs based on visible 2D keypoints. Consider training instances $\\{I, \\mathbf{j}, \\mathbf{v}\\}$ , where $I$ is the RGB image, $\\mathbf{j}$ is the corresponding visible 2D keypoints, and $\\mathbf{v}$ is an indicator variable for 2D keypoints visibility. In line with previous works [22, 25, 26], we treat the shape parameter $\\beta$ and camera parameters $\\mathbf{c}$ deterministically and assume that they can be estimated reasonably from $I$ .", + "bbox": [ + 498, + 657, + 890, + 777 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Our main interest then is to model the distribution of the pose parameter $\\theta$ , conditioned on the input image $I$ with associated $\\mathbf{j}, \\beta$ and $\\mathbf{c}$ , i.e., the conditional distribution $p(\\theta | I, \\mathbf{j}, \\mathbf{c}, \\beta)$ , which we refer to as the data distribution. To model the data distribution, we learn a model $\\phi$ in the form of a neural network. Similarly, the model $\\phi$ has the distribution $p_{\\phi}(\\theta | I, \\mathbf{j}, \\mathbf{c}, \\beta)$ , which we term as the model distribution. The model $\\phi$ can be learned by minimizing the", + "bbox": [ + 496, + 779, + 892, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "14842", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/64d911b38798484e99284aec0d75a3e340b21e6e42b2d9e22c47226a48c044bc.jpg", + "image_caption": [ + "Figure 2. Framework overview. The framework is optimized by considering three components: reconstruction, prior, and entropy (see the red double-headed arrows). The distribution of the feasible pose parameters is captured by an NF model conditioned on image features. The reconstruction applies different distributions for the visible keypoints (blue dots) and occluded keypoints (red dots)." + ], + "image_footnote": [], + "bbox": [ + 81, + 88, + 893, + 275 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Kullback-Leibler (KL) divergence between the data and the model distribution, i.e.,", + "bbox": [ + 76, + 363, + 468, + 393 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nK L \\left(p _ {\\phi} (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta) \\| p (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta)\\right). \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 151, + 406, + 468, + 422 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Data Distribution. Inspired by the existing 2D-to-3D lifting works [7, 25, 26] that a 3D pose could be accurately estimated by its corresponding 2D pose, $\\beta$ and camera information, we assume that once $\\{\\mathbf{j},\\mathbf{c},\\beta \\}$ are given, $\\theta$ and $I$ are conditionally independent. As such, $I$ can be omitted as a conditioning variable. With Bayes' rule, the data distribution can be split as:", + "bbox": [ + 75, + 441, + 468, + 547 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\np (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta) = p (\\theta | \\mathbf {j}, \\mathbf {c}, \\beta) \\propto p (\\mathbf {j} | \\mathbf {c}, \\beta , \\theta) \\cdot p (\\theta). \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 99, + 559, + 468, + 575 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The first decomposed term in Eq. (7), the likelihood $p(\\mathbf{j}|\\mathbf{c},\\beta ,\\theta)$ , is a projection consistency term that reflects the reconstruction accuracy. The second term, $p(\\theta)$ , serves as a general pose prior in a probabilistic perspective [16, 21].", + "bbox": [ + 75, + 588, + 468, + 650 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Model Distribution. Like previous works [22, 16, 21, 2], we estimate $\\theta$ from an image $I$ , as the image contains sufficient information to infer $\\mathbf{c}$ , $\\beta$ and the keypoints $\\mathbf{j}$ . The model distribution can be simplified as:", + "bbox": [ + 75, + 667, + 468, + 729 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\np _ {\\phi} (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta) = p _ {\\phi} (\\theta | I). \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 181, + 742, + 468, + 758 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Based on Eqs. (7) and (8), the KL divergence between the model and data distributions can be expressed as:", + "bbox": [ + 76, + 771, + 468, + 801 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} K L \\left(p _ {\\phi} (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta) \\| p (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta)\\right) = \\\\ - \\left(\\underbrace {\\underbrace {E _ {p _ {\\phi} (\\theta \\mid I)} [ \\log p (\\mathbf {j} \\mid \\mathbf {c} , \\beta , \\theta) ]} _ {\\text {r e c o n s t r u c t i o n}} + \\underbrace {E _ {p _ {\\phi} (\\theta \\mid I)} [ \\log p (\\theta) ]} _ {\\text {p r i o r}} + \\underbrace {H \\left(p _ {\\phi} (\\theta \\mid I)\\right)} _ {\\text {e n t r o p y}}\\right), \\tag {9} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 81, + 813, + 486, + 898 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $H(p_{\\phi}(\\theta |I)) = -E_{p_{\\phi}(\\theta |I)}[\\log p_{\\phi}(\\theta |I)]$ is the entropy of $\\theta$ given input image $I$ . See Suppl. B for the full derivation. Minimizing the KL divergence in Eq. (9) maximizes the reconstruction accuracy and the conditional entropy of the pose under pose prior $p(\\theta)$ ; this can be used directly to supervise the neural network $\\phi$ .", + "bbox": [ + 496, + 362, + 890, + 453 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Based on the above derivation, we propose a weakly-supervised multi-hypothesis framework as illustrated in Fig. 2. We consider only visible 2D keypoints as supervisory signals for the reconstruction. Like [21, 26], we assume that visible keypoints follow a Laplace distribution for sharpness. In line with the principle of maximum entropy (Sec. 3.4), the occluded keypoints each follow a uniform distribution of feasible locations. The intuition behind such an assumption is that, for occluded keypoints, we relax the supervision using prior knowledge $p(\\theta)$ to generate feasible solutions for the image. This prevents an overconfident model that tries to fit all labels regardless of visibility and also compensates for the lack of one-to-many data-label pairs. As $\\theta$ is derived from a parametric model, the prior can be applied simply as a uniform distribution [33] or adversarially [16] based on its representation. We choose to model the distribution $p_{\\phi}(\\theta |I)$ using a conditional NF model, i.e., $p_{\\phi}(\\theta |I) = \\mathcal{F}^{-1}(\\theta |I)$ , as it is more feasible to calculate the entropy term $H(p_{\\phi}(\\theta |I))$ via Monte Carlo (MC) sampling. Therefore, all three terms in Eq. (9) can be maximized by MC sampling and SGD [18].", + "bbox": [ + 496, + 458, + 892, + 775 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "An important part of our formulation involves the explicit maximization of entropy. The link between entropy and diverse hypotheses is highly intuitive, yet this has been overlooked in previous work. Even without one-to-many labels, the entropy term encourages the model $\\phi$ to generate hypotheses that are diverse; the reconstruction and prior term ensure that the hypotheses respect the observed labels while remaining feasible.", + "bbox": [ + 496, + 779, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "14843", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.2. Implementation Details", + "text_level": 1, + "bbox": [ + 76, + 90, + 294, + 107 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In Eq. (9), we represent image $I$ with image features extracted from a ResNet-50 [12] backbone. To estimate $\\mathbf{c}$ and $\\beta$ , we append a 512-hidden unit MLP to the backbone. For the normalizing flow model, we use the Real NVP[8].", + "bbox": [ + 76, + 114, + 468, + 175 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "First, to obtain $\\theta$ for an image, according to LOTUS, we sample $\\mathbf{z}_0$ from a Gaussian distribution and feed it together with image feature of $I$ to the invertible flow network $\\mathcal{F}(\\mathbf{z}|I)$ (the solid line in the yellow block in Fig. 2).", + "bbox": [ + 76, + 175, + 468, + 237 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Reconstruction. We use a constant scale $b$ for the Laplace and assume the joints do not exceed the large occlusion range (Suppl. B.2); the reconstruction loss simplifies to:", + "bbox": [ + 76, + 257, + 468, + 304 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {r e c}} = \\sum_ {k = 1} ^ {K} v _ {k} \\| \\mathbf {j} _ {k} - \\hat {\\mathbf {j}} _ {k} \\| _ {1}, \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 187, + 316, + 468, + 357 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $K$ is the number of joints and $\\mathbf{j}_k$ represents $k$ -th joint; the loss is effective only on visible joints based on visibility indicator $v_k$ .", + "bbox": [ + 76, + 369, + 468, + 414 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Prior. To encourage feasible poses, we introduce a prior term $\\mathcal{R}(\\cdot)$ on $\\theta$ . For MANO, $\\theta$ is given as PCA coefficients. We empirically place a uniform distribution $\\mathcal{R}(\\theta) = \\mathcal{U}(-2,2)$ on these coefficients, which covers most feasible solutions while avoiding invalid poses [33], i.e.,", + "bbox": [ + 76, + 436, + 468, + 512 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\theta} = \\sum_ {i} \\max (0, | \\theta_ {i} | - 2) ^ {2}. \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 176, + 523, + 468, + 554 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "For SMPL, $\\theta$ represents axis-angle rotations and can be restricted by an adversarial prior [16], i.e.,", + "bbox": [ + 76, + 566, + 468, + 598 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\theta} = \\operatorname {A d v} (\\theta). \\tag {12}\n$$\n", + "text_format": "latex", + "bbox": [ + 223, + 612, + 468, + 627 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Entropy. We use a negative log-likelihood loss:", + "bbox": [ + 76, + 648, + 405, + 662 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {H} = - \\log p _ {\\phi} (\\theta | I), \\tag {13}\n$$\n", + "text_format": "latex", + "bbox": [ + 200, + 676, + 468, + 693 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\theta$ is sampled from the normalizing flow. The reverse path of the NF, $\\mathcal{F}^{-1}(\\theta |I)$ , maps $\\theta$ back to $\\mathbf{z}_0$ in the latent space conditional on the image features to compute Eq. (4) [8, 17] (dashed lines in the yellow block in Fig. 2).", + "bbox": [ + 76, + 705, + 468, + 767 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The losses in Eqs. (10)-(13) each covers a term in Eq. (9). With the $\\beta$ regularization in Eq. (2), all losses sum into the final training objective:", + "bbox": [ + 76, + 768, + 467, + 811 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} = \\lambda_ {\\text {r e c}} \\mathcal {L} _ {\\text {r e c}} + \\lambda_ {\\theta} \\mathcal {L} _ {\\theta} + \\lambda_ {H} \\mathcal {L} _ {H} + \\lambda_ {\\beta} \\mathcal {L} _ {\\beta}, \\tag {14}\n$$\n", + "text_format": "latex", + "bbox": [ + 137, + 830, + 467, + 845 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where the $\\lambda$ s are the trade-off hyperparameters and $\\mathcal{L}_{\\beta} = ||\\beta||_2^2$ . See Suppl. B for the full derivations and more training details.", + "bbox": [ + 76, + 854, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 500, + 90, + 630, + 107 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.1. Datasets, Metrics, & Baselines", + "text_level": 1, + "bbox": [ + 500, + 114, + 767, + 128 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Datasets. We synthesize a 2-joint toy setting in 2D to highlight components of our model. For the human body, we experiment on Human3.6M (H36M) [14] and its ambiguous version AH36M [2] with randomly truncated images of H36M to hide keypoints. Following [2, 21], we train with subjects S1 and S5-9 and test with S11, training with H36M and AH36M jointly, while evaluating separately.", + "bbox": [ + 496, + 137, + 890, + 243 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Inspired by AH36M, we construct Ambiguous RHD (ARHD) from the synthetic hand pose dataset RHD [43] by adding circular patches with a predefined radius to the fingers' DIP joints1. The visibility in the scene is affected depending on the finger and circle radius (see Fig. 5(c)). We also use HO3D [11], a real-world hand-object dataset that features severe occlusions. To evaluate the multi-hypothesis metrics, similar to previous work [38], we split a test subset from the training dataset. We estimate the visibility of a joint [9] by thresholding the difference between captured surface depth and the true keypoint position. More details of the datasets are provided in Suppl. D.", + "bbox": [ + 496, + 243, + 890, + 425 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Evaluation Metrics. Mean End-Point Error (EPE) is the average Euclidean distance between predicted and ground-truth joints, from which we consider the Best Hypothesis (BH) [25, 2] and our newly proposed All Hypothesis (AH).", + "bbox": [ + 496, + 441, + 890, + 502 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "BH is a standard multi-hypothesis metric that selects the hypothesis with the lowest pose or mesh EPE. To evaluate the accuracy of all hypotheses, we propose AH, which is the mean EPE of all hypotheses on 2D visible joints to measure consistency to the image evidence.", + "bbox": [ + 496, + 503, + 890, + 577 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "As we highlighted, multiple hypotheses should be diverse, but the diversity should only be on uncertain joints e.g. under occlusion. However, existing BH and diversity metrics [34, 26] do not capture this target because undesirable diversity on the visible joints may also contribute to the diversity metrics. Therefore, we propose to complement the evaluation of multi-hypothesis methods with Per-Joint Diversity (PJD) and a Relative Diversity (RD) ratio.", + "bbox": [ + 496, + 578, + 890, + 698 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "PJD measures the standard deviation per joint and can be used to show the diversity of both visible and occluded joints in 2D and 3D spaces. To highlight the source of diversity, we propose a ratio:", + "bbox": [ + 496, + 699, + 890, + 758 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {R D} = \\frac {\\mathrm {P J D} _ {2 \\mathrm {d v i s}}}{\\mathrm {P J D} _ {3 \\mathrm {d o c c}}}, \\tag {15}\n$$\n", + "text_format": "latex", + "bbox": [ + 635, + 765, + 888, + 797 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "to account for the diversity of both the certain (i.e., 2D visible keypoints) and the uncertain parts (i.e., 3D occluded keypoints). A lower RD means more diversity on the occluded keypoints relative to visible keypoints. We follow [35, 37] and sample 200 hypotheses for evaluation.", + "bbox": [ + 496, + 803, + 890, + 878 + ], + "page_idx": 4 + }, + { + "type": "page_footnote", + "text": "1The distal interphalangeal (DIP) joint is the one closest to the fingertip.", + "bbox": [ + 517, + 886, + 888, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "14844", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/4712b23c6425c22645cf52713a09d21e9a69e9646278d1e39d8af81972351fdb.jpg", + "image_caption": [ + "(a)" + ], + "image_footnote": [], + "bbox": [ + 86, + 90, + 228, + 172 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/1bf4de5afb661faf898de40284ed9eb3cca2dc8f78e6b885cd7eb71c0d971aa4.jpg", + "image_caption": [ + "(b)" + ], + "image_footnote": [], + "bbox": [ + 228, + 90, + 349, + 172 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/35a9a440b2b7dd88061518a7fd845413e1787608d278b5ff1f8aeb30dad5bf14.jpg", + "image_caption": [ + "(c)" + ], + "image_footnote": [], + "bbox": [ + 352, + 90, + 455, + 172 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/f585497cb9d2991f6ed68443209a51ad5f62622bdb04f216cffa24e3efe6f2de.jpg", + "image_caption": [ + "Figure 3. (a) Toy problem setting featuring four modes. (b) Our probabilistic method in a weakly supervised setting recovers all the modes. (c) The deterministic method, even under strong supervision, predicts wrong modes as it easily overfits ubiquitous observation noise.", + "(a)", + "Figure 4. (a) Lowering the weight of the entropy term can impair multi-mode learning while (b) increasing the weights hurts the fitting accuracy, although it achieves diversity. (c) Choosing different feasibility priors will also make the final learned modes different. The second row shows the mode distribution in $\\alpha$ space." + ], + "image_footnote": [], + "bbox": [ + 86, + 273, + 218, + 428 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/11c277106590209922fa0cea4d5f25567d19907eb5175fba3851e76fc872a1e4.jpg", + "image_caption": [ + "(b)" + ], + "image_footnote": [], + "bbox": [ + 218, + 273, + 338, + 428 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/f40a56f853cca59e4aa5c1554420353bf8aa17c712a00fb106f6ae00ff340986.jpg", + "image_caption": [ + "(c)" + ], + "image_footnote": [], + "bbox": [ + 338, + 273, + 462, + 428 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Baselines & SOTAs. We compare our method with two deterministic methods, Det (2D Vis) and Det (3D), which use visible 2D and all 3D keypoint positions as supervision, respectively. For more details, refer to a similar pipeline in [3]. Moreover, we compare our method with the state-of-the-art multi-hypothesis methods, including MDN [25], conditional VAE [35], Multi-bodies [2], ProHMR [21], CM-VAE [36] and WS3DPG [26].", + "bbox": [ + 75, + 542, + 468, + 665 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Some of these approaches are designed with 3D pose supervision; we replace their corresponding supervised losses with the 2D version in Eq. (2). Unless specified, we also use visibility labels as weights while remaining as faithful as possible to the original method. See Suppl. F for method introductions and details.", + "bbox": [ + 75, + 666, + 468, + 755 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.2. Toy Experiments & Ablation Studies", + "text_level": 1, + "bbox": [ + 76, + 768, + 395, + 786 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Settings. We perform the toy experiment under a simple setting (depth ambiguity), as shown in Fig. 3(a). Consider a single chain with two keypoints plus a root keypoint. The bones are fixed to length 1 and the root is at the origin. The data $(\\mathbf{y},\\alpha)$ consists of the 1D projection $y_{k}$ of the keypoint on the y-axis and the angle $\\alpha_{k}$ between the chain and the y-axis. From $\\alpha_{k}$ , we can get 2D coordinates", + "bbox": [ + 75, + 794, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "$\\mathbf{j}_k = (\\sin \\alpha_k, \\cos \\alpha_k)$ relative to their parent. There are in total four Gaussian modes for the complete data, i.e., each joint can swing left and right. The model is trained to predict $\\alpha$ based on $\\mathbf{y}$ . For weak supervision, only 1D projections $\\mathbf{y}$ are given. For strong supervision, all 2D coordinates $\\mathbf{j}$ are provided. Our model uses an MLP and Real NVP as the backbone and optimizes an objective similar to Eq. (14). For the prior loss, we add an $L_2$ norm constraint on $\\alpha$ .", + "bbox": [ + 496, + 90, + 890, + 212 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Deterministic vs. Multi-Hypothesis. The deterministic model trained under both weak and strong supervision can learn only one of the four modes. Moreover, under strong supervision, it is sensitive to similar input data and predicts wrong modes if the inputs are corrupted with small perturbations (Fig. 3(c)). In contrast, existing multi-hypothesis methods can recover all modes under strong supervision.", + "bbox": [ + 496, + 234, + 890, + 340 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Ours vs. Existing Multi-Hypothesis Methods. Existing methods require similar observations with multiple distinct ground-truth poses. In the weakly supervised setting, we compare with MDN and observe that it finds only one of the modes (Suppl. G.1) while our proposed method can successfully recover all the modes (Fig. 3(b)).", + "bbox": [ + 496, + 364, + 890, + 455 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Reconstruction vs. Entropy. The entropy term encourages the set of predictions to cover diverse solutions while maintaining a low reconstruction error. As the weight of the entropy term $\\lambda_{H}$ decreases, the objective emphasizes reconstruction at the cost of entropy, leading to missed modes (Fig. 4(a)). The extreme is the degradation to a deterministic model. On the other hand, with the increase in $\\lambda_{H}$ , the model pays less attention to reconstructing observed evidence, hence the modes become dispersed (Fig. 4(b)).", + "bbox": [ + 496, + 478, + 890, + 614 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Angle Prior. The prior term determines the distribution over the feasible solution space. When we lower the weight of the prior loss, the model may fit the evidence better but consider less feasible poses. On the other hand, prior knowledge defines the solution space, and the entropy term will encourage the predictions to cover all possible solutions based on the prior. For example, when we add a prior $\\sin \\alpha_{k} \\geq 0$ for the top keypoints, some previous modes become infeasible and the model will only find two of the four original poses (Fig. 4(c)).", + "bbox": [ + 496, + 637, + 890, + 789 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.3. Synthetic Ambiguous RHD", + "text_level": 1, + "bbox": [ + 500, + 800, + 745, + 816 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Deterministic vs. Multi-Hypothesis. Table 1(a) shows that on ARHD, all the multi-hypothesis methods [25, 35, 26, 21, 37] outperform the deterministic 'Det (2D Vis)' on the BH metric. Some methods even outperform the 'Det (3D)' baseline with 3D supervision.", + "bbox": [ + 496, + 824, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "14845", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/c43eedc5f9888a5d2ea68a372519d8afd42c6282d60d81ab874048127b913e37.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ARHDHO3D
BH (mm)↓ JointAH (pix)↓PJDRD↓BH (mm)↓ JointAH (pix)↓PJDRD↓
2D Vis3D Occ2D Vis3D Occ
Det (3D) [44]20.98----23.8825.18---
Det (2D Vis)25.1114.39---24.1025.4016.85--
Multi-bodies [2]20.5215.763.505.980.5922.0723.5619.571.920.62
MDN [25]21.3318.477.1412.690.5621.2822.6718.813.480.56
CVAE [35]20.9919.957.0210.660.6621.0422.6218.904.070.61
ProHMR [21]24.4413.370.130.220.5924.0525.4117.190.160.64
CM-VAE [36]21.9916.595.6710.400.5522.2023.5418.394.940.57
WS3DPG [26]24.3417.794.617.390.6223.6724.9918.343.060.65
Ours20.3513.423.8614.420.2720.5521.8316.953.300.28
", + "bbox": [ + 88, + 88, + 883, + 253 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 1. Quantitative results on ARHD and HO3D V3. The best is marked in bold; the second best is underlined. Our method achieves competitive SOTA results; occluded keypoints are diverse while visible ones are relatively accurate, i.e., have a lower RD.", + "bbox": [ + 75, + 253, + 892, + 282 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/eb100ef281def04bd3b48b79441da824319bae60226fbb1fe5aef52c9828e6e9.jpg", + "image_caption": [ + "(a) RD: 2D Vis PJD - 3D Occ PJD" + ], + "image_footnote": [], + "bbox": [ + 81, + 305, + 330, + 454 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/8565b98b46b71b67be7e83037f96cc19f3da2eeb44fd454d30d4450cfcf11670.jpg", + "image_caption": [ + "(b) PJD Curve Along Training", + "Figure 5. Illustration on ARHD. (a) Deviation from the diagonal (dashed line) towards the lower-right indicates a better trade-off between the 2D visible accuracy and 3D occluded diversity. (b) Comparison of PJD during learning for occluded (solid line) and visible (dashed line) keypoints. Our approach has a descending trend for visible keypoints and an ascending trend for the occluded ones. (c) Multi-hypothesis meshes. The red boxes highlight the concerned occluded keypoints. Our method predicts diverse and feasible poses under occlusion while MDN's predictions are inconsistent with image evidence on visible keypoints." + ], + "image_footnote": [], + "bbox": [ + 326, + 305, + 588, + 455 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c37cdbc126cdd9baf11e5010788b63840dc6b751c50a7652c3f3ff8157067a5a.jpg", + "image_caption": [ + "(c) Qualitative Results" + ], + "image_footnote": [], + "bbox": [ + 596, + 301, + 887, + 450 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Comparisons with SOTA. Methods like MDN [25] and CVAE [35] all have low BH (Tab. 1(a)). However, their diversity (PJD) for visible and occluded keypoints is high, i.e., the entire hand is diverse. Together with a large AH, this suggests that their hypotheses as a whole do not fit the image evidence well. ProHMR [21] degenerates to an almost deterministic method, and has the lowest PJD for visible and occluded keypoints. We speculate that it is because of its reliance on the strong supervision for $\\theta$ labels. More comparisons can be found in Sec. 5.5.", + "bbox": [ + 75, + 583, + 468, + 733 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In contrast, our framework obtains lower BH and AH and higher occluded diversity (higher $\\mathrm{PJD}_{\\mathrm{occ}}$ and thus significantly lower RD). Fig. 5(a) shows that we strike a good balance between reconstruction and diversity; qualitatively, Fig. 5(c) shows that our recovered meshes are diverse and consistent with the observation.", + "bbox": [ + 75, + 736, + 470, + 825 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Connection to Existing Works & Ablation Studies. ProHMR [21], CM-VAE [36], and WS3DPG [26] are closely related to our method. Among them, ProHMR", + "bbox": [ + 75, + 854, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "is a variant without entropy optimization; CM-VAE [36] applies a single Gaussian distribution instead of our NF; WS3DPG [26] uses a GAN whose entropy is intractable. Tab. 1(a) shows that our entropy term increases the PJD significantly, especially for occluded joints in 3D (ProHMR's 0.22 vs. our 14.42). Moreover, we outperform CM-VAE and WS3DPG on all metrics on ARHD, showing the powerful ability of NFs to model complex distributions and estimate entropy. Additional ablations on visibility in Suppl. G.2 shows that adding additional supervision on occluded joints hurts diversity.", + "bbox": [ + 496, + 583, + 890, + 750 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "PJD During Training. Fig. 5(b) shows the test PJD scores throughout training. The PJD of MDN [25] for both visible and occluded keypoints decreases as training progresses. Meanwhile, CVAE [35] has the opposite trend, with increasing PJD scores for both types of keypoints. In contrast, our approach has a descending trend on the PJD of visible keypoints and an ascending trend on the occluded ones (Tab. 1(a)).", + "bbox": [ + 496, + 779, + 892, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "14846", + "bbox": [ + 480, + 945, + 519, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/544d4b0e682ae6d49f9d06d387ef5e5e81da719102965c4f285cdac949f74e66.jpg", + "image_caption": [ + "Figure 6. Visualization of our multiple hypotheses on HO3D." + ], + "image_footnote": [], + "bbox": [ + 83, + 90, + 460, + 198 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/255b6c6bc03ce4fd58a307d5c86609122933c87da8459cd2b6399b737d472f99.jpg", + "image_caption": [ + "Figure 7. Visualization of hypotheses with the smallest and largest HOI Chamfer distance in two views. Differences are highlighted with red boxes. Hypothesis selection leads to more feasible grasps." + ], + "image_footnote": [], + "bbox": [ + 76, + 244, + 464, + 339 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/9395993369b957f7e871b35ddba189b68803fe229b26a19f2ca6eb1aa7a77daa.jpg", + "image_caption": [ + "Figure 8. Qualitative results on AH36M. The legs of our hypotheses are much more diverse, while all trunks are consistent with the image. The green mesh is the ground-truth." + ], + "image_footnote": [], + "bbox": [ + 78, + 419, + 464, + 549 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4. Real-World Data: HO3D", + "text_level": 1, + "bbox": [ + 76, + 640, + 307, + 655 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "When faced with real-world ambiguous settings, such as objects occluding hands, our method is state-of-the-art compared to other multi-hypothesis methods. The results in Tab. 1(b) and Fig. 6 are consistent with the trends on the synthetic ARHD – our method has the lowest BH and RD.", + "bbox": [ + 75, + 664, + 468, + 741 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Hypothesis Selection. With additional input information, the multiple hypotheses can be filtered for an improved set of solutions. We show an example of hypothesis selection in which we select feasible grasps based on the object interaction. We simply use a post-processing strategy to select samples. Specifically, we use a hand-object interaction (HOI) feasibility metric, e.g., the widely used Chamfer distance [4]. Based on the value of the Chamfer distance, we can select hypotheses. We found it useful for picking", + "bbox": [ + 75, + 763, + 470, + 902 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "more plausible poses from hypotheses using task-related constraints. We visualize hypotheses with the lowest and highest HOI Chamfer distance in Fig. 7. Our hypotheses are all consistent with the image cues in the front camera view. From a different view, by incorporating the HOI constraint for hypotheses, we can select more feasible grasp poses.", + "bbox": [ + 496, + 90, + 893, + 183 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Meaningful Diversity. The purpose of our method is to encourage meaningful diversity; hence we treat visible and occluded joints differently. The quality of diversity can be further improved by incorporating more information about the observed ambiguity. One example is to add mask information about the occlusions; it can be incorporated into our framework as a post-hoc hypothesis selection during inference or as a reconstruction loss in Eq. (9) during training. In both ways, the error rate for out-of-occlusion can therefore be reduced without much loss in diversity (Suppl. G.2).", + "bbox": [ + 496, + 200, + 892, + 353 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.5. State-of-The-Art on H36M & AH36M", + "text_level": 1, + "bbox": [ + 500, + 362, + 826, + 378 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/cb7b76a9e0a926a2e8e3d532e17b211247a920d002e81aca90cc365970c933d7.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
SupervisionMHH36MAH36M
2D VisHMR67.485.2
ProHMR✓64.382.6
Ours✓51.366.4
3DHMR56.8-
SPIN41.1-
MDN✓42.769.5
CVAE✓46.275.1
Multi-bodies✓42.264.2
ProHMR✓36.860.1
Ours✓36.850.6
", + "bbox": [ + 524, + 396, + 867, + 547 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/bc2b3b59b83e226cea4a91429147807c1e8ef550fc9cd28fb707559270a6654c.jpg", + "table_caption": [ + "Table 2. PA-MPJPE (mm) of BH results on H36M and its ambiguous version AH36M under the supervision of visible 2D keypoints (2D Vis) and 3D keypoints (3D) with $n = 25$ ." + ], + "table_footnote": [], + "table_body": "
SupervisionAH (pix)↓PJDRD↓
2D Vis3D Occ
2D VisProHMR10.920.060.260.23
Ours9.754.5664.050.07
3DProHMR13.383.9824.270.16
Ours10.734.2347.950.09
", + "bbox": [ + 504, + 617, + 890, + 700 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 3. Diversity metrics on AH36M under the supervision of visible 2D keypoints (2D Vis) and 3D keypoints (3D).", + "bbox": [ + 500, + 703, + 890, + 732 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Our framework is also effective for human pose estimation. We follow [2, 21] and evaluate the accuracy and diversity of hypotheses on the benchmark H36M and its ambiguous version AH36M. Besides using 2D visible keypoints as supervision, we also test a variant using 3D keypoints. For supervision with 3D keypoints, we follow ProHMR [21] and supervise the predicted 3D poses from SMPL directly.", + "bbox": [ + 496, + 750, + 890, + 854 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Tab. 2 shows that we achieve the best BH on both datasets with different supervision settings. Our method has an impressive $9.5\\mathrm{mm}$ improvement on AH36M with 3D", + "bbox": [ + 496, + 854, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "14847", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "keypoints as labels; furthermore, our performance with 2D visible keypoints as weak labels is comparable to using 3D keypoints as labels. Comparing diversity metrics in Tab. 3 and Fig. 8, we outperform ProHMR with respect to AH and RD. Our method with the entropy term predicts highly diverse results in the weakly-supervised setting.", + "bbox": [ + 75, + 90, + 472, + 183 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/7ca74eb89a126bf8c6bbf589dd51e663d76483228989c0690d744f2940f54698.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
H36MAH36M
Multi-ViewFittingFitting
ProHMR34.534.861.4
Ours34.234.453.5
", + "bbox": [ + 130, + 196, + 416, + 253 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 4. PA-MPJPE (mm) of downstream tasks multi-view refinement and fitting humans with 2D ground-truth. For these tasks, a trained model distribution outputs only one hypothesis by observing more evidence.", + "bbox": [ + 75, + 253, + 470, + 309 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Downstream Tasks. Our method, by estimating an accurate yet diverse set of hypotheses, excels at providing inputs for downstream tasks. We verify the hypotheses through multi-view refinement and fitting humans with 2D ground-truth on H36M and AH36M. We follow ProHMR to find the solution that best matches the evidence among many possible hypotheses by optimization, i.e.,", + "bbox": [ + 75, + 349, + 468, + 455 + ], + "page_idx": 8 + }, + { + "type": "equation", + "text": "\n$$\n\\max _ {\\theta} \\log p _ {\\phi} (\\theta | I) + c (\\theta | \\mathbf {e}), \\tag {16}\n$$\n", + "text_format": "latex", + "bbox": [ + 179, + 470, + 468, + 492 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "where $c(\\theta | \\mathbf{e})$ is consistency with additional information, e.g., multi-view and 2D projection consistency. Lower PA-MPJPE in Tab. 4 verifies our effectiveness, which may imply ours obtains a better representation with a more accurate distribution than ProHMR.", + "bbox": [ + 75, + 506, + 468, + 583 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Discussion & Conclusion", + "text_level": 1, + "bbox": [ + 76, + 599, + 310, + 617 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Our proposed multi-hypothesis framework is flexible, efficient, and label-friendly. We emphasize that diversity in the hypotheses should not be arbitrary; instead, it should come from ambiguity present in the image itself. To that end, we also propose a more comprehensive evaluation scheme based on visibility. In our work, we have only considered ambiguity from object occlusions and image truncations, but additional factors such as image quality and light are interesting directions to investigate for future work.", + "bbox": [ + 75, + 627, + 468, + 763 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We note that by virtue of evaluating on the provided annotations of the current datasets, the diversity concept remains vague and limited to the dataset. For instance, in-distribution testing aims to learn the pose diversity captured in that dataset. It may not require learning more diverse outdoor poses to achieve a good BH on indoor datasets and thus not conducive to generalization to other scenarios. It is suggested to focus more on the improvement and evaluation of the diversity in the generalization scenario.", + "bbox": [ + 75, + 763, + 470, + 901 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgments. This research/project is supported by the Ministry of Education, Singapore, under its MOE Academic Research Fund Tier 2 (STEM RIE2025 MOET2EP20220-0015). We would also like to thank the ACs, reviewers, Dr. Chen Li, and Junpeng Hu for their valuable suggestions.", + "bbox": [ + 496, + 90, + 890, + 181 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 501, + 195, + 596, + 210 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Mahmoud Assran, Mathilde Caron, Ishan Misra, Piotr Bojanowski, Florian Bordes, Pascal Vincent, Armand Joulin, Mike Rabbat, and Nicolas Ballas. Masked siamese networks for label-efficient learning. In ECCV, 2022. 3", + "[2] Benjamin Biggs, David Novotny, Sebastien Ehrhardt, Hanbyul Joo, Ben Graham, and Andrea Vedaldi. 3D Multibodies: Fitting sets of plausible 3D human models to ambiguous image data. In NeurIPS, 2020. 1, 2, 4, 5, 6, 7, 8", + "[3] Adnane Boukhayma, Rodrigo de Bem, and Philip HS Torr. 3D hand shape and pose from images in the wild. In CVPR, 2019. 1, 2, 3, 6", + "[4] Zhe Cao, Ilija Radosavovic, Angjoo Kanazawa, and Jitendra Malik. Reconstructing hand-object interactions in the wild. In ICCV, 2021. 8", + "[5] Ping Chen, Yujin Chen, Dong Yang, Fangyin Wu, Qin Li, Qingpei Xia, and Yong Tan. I2UV-HandNet: Image-to-UV prediction network for accurate and high-fidelity 3D hand mesh modeling. In ICCV, 2021. 2", + "[6] Zerui Chen, Yana Hasson, Cordelia Schmid, and Ivan Laptev. AlignSDF: Pose-aligned signed distance fields for hand-object reconstruction. In ECCV, 2022. 2", + "[7] Hongsuk Choi, Gyeongsik Moon, and Kyoung Mu Lee. Pose2Mesh: Graph convolutional network for 3D human pose and mesh recovery from a 2D human pose. In ECCV, 2020. 1, 4", + "[8] Laurent Dinh, Jascha Sohl-Dickstein, and Samy Bengio. Density estimation using real NVP. In ICLR, 2017. 3, 5", + "[9] Kerui Gu, Linlin Yang, and Angela Yao. Removing the bias of integral pose regression. In ICCV, 2021. 5", + "[10] Silviu Guiasu and Abe Shenitzer. The principle of maximum entropy. Math. Intell., 7(1):42-48, 1985. 2, 3", + "[11] Shreyas Hampali, Mahdi Rad, Markus Oberweger, and Vincent Lepetit. HOnnotate: A method for 3D annotation of hand and object poses. In CVPR, 2020. 5", + "[12] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, 2016. 5", + "[13] R Devon Hjelm, Alex Fedorov, Samuel Lavoie-Marchildon, Karan Grewal, Phil Bachman, Adam Trischler, and Yoshua Bengio. Learning deep representations by mutual information estimation and maximization. In ICLR, 2019. 3", + "[14] Catalin Ionescu, Dragos Papava, Vlad Olaru, and Cristian Sminchisescu. Human3.6M: Large scale datasets and predictive methods for 3D human sensing in natural environments. TPAMI, 36(7):1325-1339, 2013. 5", + "[15] Umar Iqbal, Pavlo Molchanov, Thomas Breuel Juergen Gall, and Jan Kautz. Hand pose estimation via latent 2.5D heatmap regression. In ECCV, 2018. 1" + ], + "bbox": [ + 501, + 219, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "14848", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[16] Angjoo Kanazawa, Michael J Black, David W Jacobs, and Jitendra Malik. End-to-end recovery of human shape and pose. In CVPR, 2018. 2, 3, 4, 5", + "[17] Durk P Kingma and Prafulla Dhariwal. Glow: Generative flow with invertible 1x1 convolutions. In NeurIPS, 2018. 5", + "[18] Diederik P. Kingma and Max Welling. Auto-encoding variational Bayes. In ICLR, 2014. 4", + "[19] Muhammed Kocabas, Nikos Athanasiou, and Michael J Black. VIBE: Video inference for human body pose and shape estimation. In CVPR, 2020. 2", + "[20] Nikos Kolotouros, Georgios Pavlakos, Michael J Black, and Kostas Daniilidis. Learning to reconstruct 3D human pose and shape via model-fitting in the loop. In ICCV, 2019. 2", + "[21] Nikos Kolotouros, Georgios Pavlakos, Dinesh Jayaraman, and Kostas Daniilidis. Probabilistic modeling for human mesh recovery. In ICCV, 2021. 1, 2, 4, 5, 6, 7, 8", + "[22] Dominik Kulon, Riza Alp Guler, Iasonas Kokkinos, Michael M Bronstein, and Stefanos Zafeiriou. Weakly-supervised mesh-convolutional hand reconstruction in the wild. In CVPR, 2020. 2, 3, 4", + "[23] Rithesh Kumar, Sherjil Ozair, Anirudh Goyal, Aaron Courville, and Yoshua Bengio. Maximum entropy generators for energy-based models. In arXiv:1901.08508, 2019. 3", + "[24] Jogendra Nath Kundu, Siddharth Seth, Pradyumna YM, Varun Jampani, Anirban Chakraborty, and R Venkatesh Babu. Uncertainty-aware adaptation for self-supervised 3d human pose estimation. In CVPR, 2022. 3", + "[25] Chen Li and Gim Hee Lee. Generating multiple hypotheses for 3D human pose estimation with mixture density network. In CVPR, 2019. 1, 2, 3, 4, 5, 6, 7", + "[26] Chen Li and Gim Hee Lee. Weakly supervised generative network for multiple 3D human pose hypotheses. In BMVC, 2020. 1, 3, 4, 5, 6, 7", + "[27] Wenhao Li, Hong Liu, Hao Tang, Pichao Wang, and Luc Van Gool. MHFormer: Multi-hypothesis transformer for 3D human pose estimation. In CVPR, 2022. 1", + "[28] Kevin Lin, Lijuan Wang, and Zicheng Liu. End-to-end human pose and mesh reconstruction with transformers. In CVPR, 2021. 1, 2", + "[29] Xin Liu, Zhongdao Wang, Ya-Li Li, and Shengjin Wang. Self-supervised learning via maximum entropy coding. 2022. 3", + "[30] Matthew Loper, Naureen Mahmood, Javier Romero, Gerard Pons-Moll, and Michael J Black. SMPL: A skinned multiperson linear model. TOG, 34(6):1-16, 2015. 2, 3", + "[31] Gyeongsik Moon and Kyoung Mu Lee. I2L-MeshNet: Image-to-lixel prediction network for accurate 3D human pose and mesh estimation from a single RGB image. In ECCV, 2020. 1, 2", + "[32] George Papamakarios, Eric T Nalisnick, Danilo Jimenez Rezende, Shakir Mohamed, and Balaji Lakshminarayanan. Normalizing flows for probabilistic modeling and inference. JMLR, 22(57):1-64, 2021. 3", + "[33] Javier Romero, Dimitrios Tzionas, and Michael J. Black. Embodied Hands: Modeling and capturing hands and bodies together. TOG, 36(6):1-17, 2017. 2, 3, 4, 5" + ], + "bbox": [ + 78, + 90, + 468, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[34] Akash Sengupta, Ignas Budvytis, and Roberto Cipolla. Hierarchical kinematic probability distributions for 3D human shape and pose estimation from images in the wild. In ICCV, 2021. 5", + "[35] Saurabh Sharma, Pavan Teja Varigonda, Prashast Bindal, Abhishek Sharma, and Arjun Jain. Monocular 3D human pose estimation by generation and ordinal ranking. In ICCV, 2019. 1, 2, 5, 6, 7", + "[36] Adrian Spurr, Jie Song, Seonwook Park, and Otmar Hilliges. Cross-modal deep variational hand pose estimation. In CVPR, 2018. 6, 7", + "[37] Tom Wehrbein, Marco Rudolph, Bodo Rosenhahn, and Bastian Wandt. Probabilistic monocular 3D human pose estimation with normalizing flows. In ICCV, 2021. 1, 2, 5, 6", + "[38] Lixin Yang, Xinyu Zhan, Kailin Li, Wenqiang Xu, Jiefeng Li, and Cewu Lu. CPF: Learning a contact potential field to model the hand-object interaction. In ICCV, 2021. 5", + "[39] Qi Ye and Tae-Kyun Kim. Occlusion-aware hand pose estimation using hierarchical mixture density network. In ECCV, 2018. 1, 2", + "[40] Ziwei Yu, Linlin Yang, You Xie, Ping Chen, and Angela Yao. UV-based 3D hand-object reconstruction with grasp optimization. In BMVC, 2022. 2", + "[41] Andrei Zanfir, Eduard Gabriel Bazavan, Hongyi Xu, William T Freeman, Rahul Sukthankar, and Cristian Sminchisescu. Weakly supervised 3D human pose and shape reconstruction with normalizing flows. In ECCV, 2020. 2", + "[42] Wang Zeng, Wanli Ouyang, Ping Luo, Wentao Liu, and Xiaogang Wang. 3D human mesh regression with dense correspondence. In CVPR, 2020. 2", + "[43] Christian Zimmermann and Thomas Brox. Learning to estimate 3D hand pose from single RGB images. In ICCV, 2017. 5", + "[44] Christian Zimmermann, Duygu Ceylan, Jimei Yang, Bryan Russell, Max Argus, and Thomas Brox. FreiHAND: A dataset for markerless capture of hand pose and shape from single RGB images. In ICCV, 2019. 7" + ], + "bbox": [ + 501, + 92, + 890, + 616 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "14849", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/f9c54455-f324-48c7-9865-4e8d15caf336_model.json b/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/f9c54455-f324-48c7-9865-4e8d15caf336_model.json new file mode 100644 index 0000000000000000000000000000000000000000..13eec093e5b4ade2aba89ba3b16d295bb1e4e4dd --- /dev/null +++ b/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/f9c54455-f324-48c7-9865-4e8d15caf336_model.json @@ -0,0 +1,2530 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.085, + 0.131, + 0.885, + 0.155 + ], + "angle": 0, + "content": "MHEntropy: Entropy Meets Multiple Hypotheses for Pose and Shape Recovery" + }, + { + "type": "text", + "bbox": [ + 0.292, + 0.181, + 0.681, + 0.234 + ], + "angle": 0, + "content": "Rongyu Chen* Linlin Yang* Angela Yao National University of Singapore {rchen, yangll, ayao}@comp.nus.edu.sg" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.269, + 0.314, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.302, + 0.474, + 0.545 + ], + "angle": 0, + "content": "For monocular RGB-based 3D pose and shape estimation, multiple solutions are often feasible due to factors like occlusions and truncations. This work presents a multi-hypothesis probabilistic framework by optimizing the Kullback-Leibler divergence (KLD) between the data and model distribution. Our formulation reveals a connection between the pose entropy and diversity in the multiple hypotheses that has been neglected by previous works. For a comprehensive evaluation, besides the best hypothesis (BH) metric, we factor in visibility for evaluating diversity. Additionally, our framework is label-friendly - it can be learned from only partial 2D keypoints, such as visible keypoints. Experiments on both ambiguous and real-world benchmarks demonstrate that our method outperforms other state-of-the-art multi-hypothesis methods. The project page is at https://gloryyrolg.github.io/MHEntropy." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.575, + 0.21, + 0.59 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.602, + 0.47, + 0.768 + ], + "angle": 0, + "content": "Pose and shape estimation is a core component of augmented and virtual reality applications. The majority of monocular 3D pose and shape estimation approaches [28, 31, 7, 3, 15] are designed to predict only a single solution, yet 3D recovery from a monocular input is an inverse problem. Multiple solutions are feasible, especially under settings with occlusions, truncations, low image quality, or other ambiguities. It is therefore meaningful and desirable to make multi-hypothesis predictions. Multiple hypotheses are also useful in downstream tasks such as 2D keypoint fitting [21] and multi-view fusion [21, 25]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.769, + 0.471, + 0.875 + ], + "angle": 0, + "content": "Previous multi-hypothesis works use various 2D [2, 21, 37], 3D [39, 25, 2, 21, 37, 35], and mesh [2] reconstruction losses to facilitate kinematically feasible poses and shapes, while encouraging diversity in the solution set. Yet the learning and evaluation for multi-hypothesis works are underdeveloped. Learning-wise, many existing works are not label-friendly and often require one-to-many labeled data to" + }, + { + "type": "image", + "bbox": [ + 0.547, + 0.275, + 0.673, + 0.372 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.551, + 0.381, + 0.655, + 0.394 + ], + "angle": 0, + "content": "(a) Occluded Input" + }, + { + "type": "image", + "bbox": [ + 0.693, + 0.285, + 0.834, + 0.366 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.679, + 0.381, + 0.83, + 0.393 + ], + "angle": 0, + "content": "(b) Visible versus Occluded" + }, + { + "type": "image", + "bbox": [ + 0.558, + 0.401, + 0.646, + 0.465 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.655, + 0.4, + 0.729, + 0.468 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.74, + 0.4, + 0.841, + 0.469 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.616, + 0.473, + 0.748, + 0.486 + ], + "angle": 0, + "content": "(c) Multiple Hypotheses" + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.49, + 0.892, + 0.519 + ], + "angle": 0, + "content": "Figure 1. Our method estimates diverse and feasible hypotheses for occluded joints while preserving accuracy for visible joints." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.55, + 0.893, + 0.686 + ], + "angle": 0, + "content": "achieve diversity [21, 2, 35, 25], i.e., similar ambiguous observations with multiple distinct ground-truth poses. Such labels are challenging to obtain, especially under occlusion or out-of-view scenarios for which multi-hypothesis predictions are the most meaningful. While empirical efforts have been made to avoid mode collapse while encouraging diversity [26, 27], these methods often do not fully explore the solution space. It is, therefore, non-trivial to achieve feasible and as diverse as possible solutions." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.69, + 0.895, + 0.902 + ], + "angle": 0, + "content": "Evaluation-wise, multi-hypothesis works use the best hypothesis (BH) as the metric of choice [25, 2, 21, 37, 26]. BH measures the closest distance between a hypothesis set and the ground truth. It emphasizes the accuracy of the closest hypothesis while ignoring the set holistically. Few works explicitly and quantitatively evaluate the diversity of the predicted hypotheses. When they do so, diversity is evaluated independently from the input [26]. Yet joints under occlusion or a lack of evidence feature more uncertainty, and as such should correspond to more diversity, while joints should be less diverse on unambiguous parts. Current multi-hypothesis evaluation schemes do not make such distinctions. Unwanted diversity on unambiguous joints also contributes to the calculation of overall diversity." + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.888, + 0.206, + 0.9 + ], + "angle": 0, + "content": "*Equal contribution." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "14840" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.364 + ], + "angle": 0, + "content": "This paper addresses these shortcomings and presents a new multi-hypothesis framework for estimating 3D poses and shapes. At the heart of our method is a simple yet essential underlying criterion - hypotheses should be diverse, but meaningfully so, and correlate with an observation's ambiguity (see Fig. 1 (b)). To that end, we take a probabilistically principled approach and minimize the Kullback-Leibler (KL) divergence between the model distribution and the underlying data distribution. Our objective results in three terms: a reconstruction accuracy, a pose prior, and most interestingly, a model entropy term. This additional entropy term echoes the principle of maximum entropy [10], where the probability distribution is designed to align with observations but otherwise be as unbiased as possible. For pose estimation, this means that visible and unambiguous keypoints should remain fixed across the hypotheses, while occluded and ambiguous keypoints should be feasible yet diverse (see Fig. 1 (b) and (c))." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.364, + 0.473, + 0.499 + ], + "angle": 0, + "content": "Unlike existing works [35, 25, 21], our formulation for diversity does not require one-to-many training data. Instead, our model is trained by explicitly encouraging it to explore the feasible solution space via entropy maximization while remaining consistent with the evidence. For the implementation of our framework, we learn a conditional distribution of parameters with a normalizing flow model. The parameters modelled come from parametric 3D models like MANO [33] and SMPL [30]." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.5, + 0.473, + 0.605 + ], + "angle": 0, + "content": "To be label-friendly, we advocate using weak labels; specifically, we recommend 2D keypoints from only visible joints. Using 2D keypoint labels is well established in the literature [3, 22]. However, considering only visible 2D keypoints is not well-studied, even though it is highly intuitive from an annotation point of view and a natural fit for multiple hypotheses." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.606, + 0.473, + 0.756 + ], + "angle": 0, + "content": "For a comprehensive evaluation beyond the best hypothesis we introduce a Per-Joint Diversity (PJD) to measure the diversity of visible and occluded keypoints. Based on PJD, we further propose a Relative Diversity (RD) ratio to measure the reasonable diversity of the hypotheses. A low ratio indicates that observed keypoints are deterministic while occluded keypoints are diverse. In experiments, our method finds highly accurate BH and achieves the best RD ratio compared to other multi-hypothesis approaches. To summarize our contributions," + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.77, + 0.47, + 0.845 + ], + "angle": 0, + "content": "- We formulate multi-hypothesis estimation as a minimization of the KL divergence between the model distribution and the data distribution. This formulation is probabilistically principled and naturally yields an entropy term that encourages diversity in the solution set." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.856, + 0.47, + 0.901 + ], + "angle": 0, + "content": "- From our KL formulation, we propose a framework to estimate multiple hypotheses of 3D pose and shape that favours feasible and diverse solutions by design." + }, + { + "type": "list", + "bbox": [ + 0.097, + 0.77, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.092, + 0.892, + 0.152 + ], + "angle": 0, + "content": "- We emphasize visibility in multi-hypothesis frameworks by exploring visible 2D keypoints, i.e. partial weak labels for estimating 3D pose and shape and factoring in visibility for evaluating diversity." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.169, + 0.894, + 0.229 + ], + "angle": 0, + "content": "- Experiments on toy, ambiguous, and real-world data demonstrate that our method achieves excellent diversity and the best BH compared to other state-of-the-art multi-hypothesis methods." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.092, + 0.894, + 0.229 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.249, + 0.642, + 0.265 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.275, + 0.855, + 0.292 + ], + "angle": 0, + "content": "2.1. 3D Human/Hand Pose & Shape Recovery" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.3, + 0.895, + 0.497 + ], + "angle": 0, + "content": "Existing works estimate 3D pose and shape either directly [3, 16, 20, 19], or indirectly [5, 28, 31] via a parametric model like SMPL and MANO. Parametric models serve as priors to encourage feasible solutions [3, 16] and reduce the reliance on labels [22, 41]. The parameters of parametric models are typically learned under the supervision of 3D meshes and poses [3, 16, 20, 19]. Without parametric models, works like [42, 5, 28, 31, 22] focus on the representations of 3D surfaces and the design of architectures. They convert the surfaces into different 3D representations like mesh vertices [31, 28], UV mapping [42, 5, 40], and implicit representations [6], and then fit the surfaces based on architectures like GCNs [22] and Transformers [28]." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.51, + 0.742, + 0.527 + ], + "angle": 0, + "content": "2.2. Multi-Hypothesis Methods" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.535, + 0.894, + 0.672 + ], + "angle": 0, + "content": "These methods predict diverse and feasible predictions from ambiguous input evidence, often via deep generative models. The work in [35] proposes a conditional VAE to model the distribution of a 3D pose sample set that is consistent with the 2D pose, which helps to tackle the inherent ambiguity in 2D-to-3D lifting. MDN-based works [39, 25] introduce mixture density models to estimate multiple hypotheses by minimizing the negative log-likelihood of a multi-modal mixture of Gaussians." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.673, + 0.894, + 0.824 + ], + "angle": 0, + "content": "More recent works [37, 2, 21] apply normalizing flow (NF) models. The work in [2] directly employs NFs as a prior on the distribution of plausible poses at test time. Differently, other works, like [37, 21], propose using a conditional NF. Specifically, [21] uses the conditional NF to model the distribution of SMPL pose parameters conditioned on the 2D image, while [37] adopts predicted 2D keypoints as a condition for the NF and specifically considers 2D poses in the latent space to model the distribution from 3D poses to 2D poses and its reverse." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.894, + 0.903 + ], + "angle": 0, + "content": "Despite their use of probabilistic modeling, few existing works use explicit distributional optimization objectives. Our proposed method is derived directly from KL divergence, which also brings an entropy term and explicitly encourages the estimation of multiple hypotheses." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "14841" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.09, + 0.218, + 0.106 + ], + "angle": 0, + "content": "3. Preliminaries" + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.139, + 0.36, + 0.155 + ], + "angle": 0, + "content": "3.1. Overview of Parametric Models" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.162, + 0.47, + 0.298 + ], + "angle": 0, + "content": "MANO [33] and SMPL [30] are commonly-used parametric 3D models for human hands and bodies with pose parameters \\(\\theta \\in \\mathbb{R}^{N_{\\theta}}\\) and shape parameters \\(\\beta \\in \\mathbb{R}^{N_{\\beta}}\\). Usually, \\(\\theta\\) and \\(\\beta\\) are expressed as axis-angle rotations and PCA coefficients learned from pose data and registered shapes, respectively, though \\(\\theta\\) can also be expressed as PCA coefficients for MANO. Together, \\(\\theta\\) and \\(\\beta\\) fully determine the surface mesh \\(\\mathcal{M}(\\theta ,\\beta)\\in \\mathbb{R}^{N_m\\times 3}\\) and joint coordinates \\(\\mathcal{J}(\\theta ,\\beta)\\in \\mathbb{R}^{N_j\\times 3}\\) in the 3D space." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.298, + 0.471, + 0.36 + ], + "angle": 0, + "content": "Given camera parameters \\(\\mathbf{c} = \\{R, \\mathbf{t}, s\\}\\), where \\(R \\in \\mathbb{R}^{3 \\times 3}\\) is a global rotation matrix, \\(\\mathbf{t} \\in \\mathbb{R}^2\\) is the translation, and \\(s\\) is a scaling factor, the 3D pose \\(\\mathcal{J}(\\theta, \\beta)\\) can be projected into 2D joints \\(\\mathbf{j}\\) with an orthographic projection \\(\\Pi\\):" + }, + { + "type": "equation", + "bbox": [ + 0.178, + 0.369, + 0.47, + 0.386 + ], + "angle": 0, + "content": "\\[\n\\mathbf {j} = s \\cdot \\Pi (R \\cdot \\mathcal {J} (\\theta , \\beta)) + \\mathbf {t}. \\tag {1}\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.394, + 0.307, + 0.41 + ], + "angle": 0, + "content": "3.2. 2D Keypoint Supervision" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.417, + 0.47, + 0.526 + ], + "angle": 0, + "content": "One weakly-supervised variant of monocular 3D pose and shape estimation is learned from only 2D keypoint annotations. A common approach [3] is to estimate the MANO or SMPL parameters \\((\\hat{\\theta},\\hat{\\beta})\\) for a given image and project the resulting 3D pose back into 2D joints \\(\\hat{\\mathbf{j}}\\), as per Eq. (1). The parameters can be learned with ground-truth 2D joints \\(\\mathbf{j}\\) by minimizing the following objective:" + }, + { + "type": "equation", + "bbox": [ + 0.151, + 0.532, + 0.47, + 0.552 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} = \\left\\| \\mathbf {j} - \\hat {\\mathbf {j}} \\right\\| _ {1} + \\lambda_ {\\theta} \\mathcal {R} (\\hat {\\theta}) + \\lambda_ {\\beta} \\| \\hat {\\beta} \\| _ {2} ^ {2}, \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.56, + 0.47, + 0.637 + ], + "angle": 0, + "content": "featuring a 2D reconstruction loss, a prior term \\(\\mathcal{R}(\\cdot)\\) on \\(\\theta\\) to encourage feasible poses, an \\(l_{2}\\) regularization on \\(\\beta\\), and weighting hyperparameters \\(\\lambda_{\\theta}\\) and \\(\\lambda_{\\beta}\\). The pose prior \\(\\mathcal{R}(\\cdot)\\) could be adversarial prior for rotation representations [16] or an \\(l_{2}\\) regularization for PCA coefficients [33]." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.644, + 0.254, + 0.661 + ], + "angle": 0, + "content": "3.3. Normalizing Flow" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.667, + 0.469, + 0.757 + ], + "angle": 0, + "content": "Normalizing Flows [32] are generative models with strong modeling capacity for complex, multi-modal distributions. Let \\(\\mathbf{X}\\) denote a \\(d\\)-dimensional random variable under distribution \\(P(\\mathbf{X})\\). The normalizing flow model represents \\(\\mathbf{X}\\) as a series of invertible mappings \\(\\{f_l\\}_{l=1}^L: \\mathbb{R}^d \\mapsto \\mathbb{R}^d\\) on \\(d\\)-dimensional random variable \\(\\mathbf{Z}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.154, + 0.767, + 0.469, + 0.785 + ], + "angle": 0, + "content": "\\[\n\\mathbf {X} = \\mathcal {F} (\\mathbf {Z}) = f _ {L} \\circ \\dots \\circ f _ {2} \\circ f _ {1} (\\mathbf {Z}). \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.793, + 0.469, + 0.854 + ], + "angle": 0, + "content": "Typically, the base distribution \\( P(\\mathbf{Z}) \\) is simple, e.g., a normal distribution \\( \\mathcal{N}(\\mathbf{0},\\mathbf{I}) \\). By some specially designed structures of flow blocks [8] and the change-of-variable rule [8], we can get the log-probability density of \\( \\mathbf{X} \\) as:" + }, + { + "type": "equation", + "bbox": [ + 0.116, + 0.863, + 0.47, + 0.905 + ], + "angle": 0, + "content": "\\[\n\\log P (\\mathbf {X}) = \\log P (\\mathbf {Z}) - \\sum_ {l = 1} ^ {L} \\log \\left| \\det \\frac {\\partial f _ {l}}{\\partial \\mathbf {Z} _ {l - 1}} \\right|, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.091, + 0.892, + 0.228 + ], + "angle": 0, + "content": "where, \\(\\mathbf{Z}_l = f_l(\\mathbf{Z}_{l-1}), \\mathbf{Z}_0 = \\mathbf{Z}\\) and \\(\\mathbf{Z}_L = \\mathbf{X}\\). Normalizing flows estimate the likelihood with the reverse flow \\(\\mathcal{F}^{-1}(\\mathbf{X})\\) transforming \\(\\mathbf{X}\\) to \\(\\mathbf{Z}\\). For sampling, it first samples \\(\\mathbf{z}\\) from \\(P(\\mathbf{Z})\\), and passes \\(\\mathbf{z}\\) through the flow \\(\\mathcal{F}\\) to get \\(\\mathbf{x}\\). Normalizing flows are favoured as generative models because they can tractably estimate the exact likelihood and be optimized through Maximum Likelihood Estimation (MLE). Furthermore, they can also be optimized by sampling through the Law of the Unconscious Statistician (LOTUS)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.239, + 0.779, + 0.257 + ], + "angle": 0, + "content": "3.4. Principle of Maximum Entropy" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.263, + 0.892, + 0.295 + ], + "angle": 0, + "content": "The entropy of random variable \\(\\mathbf{X}\\) taking values in \\(\\mathcal{X}\\), \\(H(\\mathbf{X})\\), quantifies the uncertainty of \\(\\mathbf{X}\\). It is defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.585, + 0.307, + 0.892, + 0.34 + ], + "angle": 0, + "content": "\\[\nH (\\mathbf {X}) = - \\int_ {\\mathcal {X}} p (\\mathbf {x}) \\log p (\\mathbf {x}) d \\mathbf {x}. \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.35, + 0.892, + 0.396 + ], + "angle": 0, + "content": "Methods such as heuristic objectives [26] and mutual information [13, 23] have been proposed to estimate and optimize entropy." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.397, + 0.893, + 0.594 + ], + "angle": 0, + "content": "Under the principle of maximum entropy [10], the probability distribution that most accurately reflects the current state of the system is the one with the highest entropy. In the context of 3D pose and shape estimation, the distribution should be compatible with complete observations, i.e. visible joints, but otherwise be as unbiased as possible for incomplete or ambiguous observations to maximize the entropy. This prevents unnecessary information from being assumed inadvertently. Especially, entropy maximization has garnered significant attention on efficient learning e.g., self-supervised learning [1, 29] and semi-supervised learning [24]. It is used to remove inadvertent assumptions and encourage the model to explore the full set of prototypes." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.609, + 0.636, + 0.627 + ], + "angle": 0, + "content": "4. Methodology" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.634, + 0.628, + 0.649 + ], + "angle": 0, + "content": "4.1. Framework" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.659, + 0.892, + 0.779 + ], + "angle": 0, + "content": "We target multi-hypothesis 3D pose and shape recovery from RGB inputs based on visible 2D keypoints. Consider training instances \\(\\{I, \\mathbf{j}, \\mathbf{v}\\}\\), where \\(I\\) is the RGB image, \\(\\mathbf{j}\\) is the corresponding visible 2D keypoints, and \\(\\mathbf{v}\\) is an indicator variable for 2D keypoints visibility. In line with previous works [22, 25, 26], we treat the shape parameter \\(\\beta\\) and camera parameters \\(\\mathbf{c}\\) deterministically and assume that they can be estimated reasonably from \\(I\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.893, + 0.902 + ], + "angle": 0, + "content": "Our main interest then is to model the distribution of the pose parameter \\(\\theta\\), conditioned on the input image \\(I\\) with associated \\(\\mathbf{j}, \\beta\\) and \\(\\mathbf{c}\\), i.e., the conditional distribution \\(p(\\theta | I, \\mathbf{j}, \\mathbf{c}, \\beta)\\), which we refer to as the data distribution. To model the data distribution, we learn a model \\(\\phi\\) in the form of a neural network. Similarly, the model \\(\\phi\\) has the distribution \\(p_{\\phi}(\\theta | I, \\mathbf{j}, \\mathbf{c}, \\beta)\\), which we term as the model distribution. The model \\(\\phi\\) can be learned by minimizing the" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "14842" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.089, + 0.895, + 0.276 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.297, + 0.893, + 0.34 + ], + "angle": 0, + "content": "Figure 2. Framework overview. The framework is optimized by considering three components: reconstruction, prior, and entropy (see the red double-headed arrows). The distribution of the feasible pose parameters is captured by an NF model conditioned on image features. The reconstruction applies different distributions for the visible keypoints (blue dots) and occluded keypoints (red dots)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.364, + 0.47, + 0.394 + ], + "angle": 0, + "content": "Kullback-Leibler (KL) divergence between the data and the model distribution, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.153, + 0.407, + 0.47, + 0.423 + ], + "angle": 0, + "content": "\\[\nK L \\left(p _ {\\phi} (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta) \\| p (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta)\\right). \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.442, + 0.47, + 0.548 + ], + "angle": 0, + "content": "Data Distribution. Inspired by the existing 2D-to-3D lifting works [7, 25, 26] that a 3D pose could be accurately estimated by its corresponding 2D pose, \\(\\beta\\) and camera information, we assume that once \\(\\{\\mathbf{j},\\mathbf{c},\\beta \\}\\) are given, \\(\\theta\\) and \\(I\\) are conditionally independent. As such, \\(I\\) can be omitted as a conditioning variable. With Bayes' rule, the data distribution can be split as:" + }, + { + "type": "equation", + "bbox": [ + 0.1, + 0.56, + 0.469, + 0.577 + ], + "angle": 0, + "content": "\\[\np (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta) = p (\\theta | \\mathbf {j}, \\mathbf {c}, \\beta) \\propto p (\\mathbf {j} | \\mathbf {c}, \\beta , \\theta) \\cdot p (\\theta). \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.589, + 0.47, + 0.651 + ], + "angle": 0, + "content": "The first decomposed term in Eq. (7), the likelihood \\( p(\\mathbf{j}|\\mathbf{c},\\beta ,\\theta) \\), is a projection consistency term that reflects the reconstruction accuracy. The second term, \\( p(\\theta) \\), serves as a general pose prior in a probabilistic perspective [16, 21]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.669, + 0.469, + 0.731 + ], + "angle": 0, + "content": "Model Distribution. Like previous works [22, 16, 21, 2], we estimate \\(\\theta\\) from an image \\(I\\), as the image contains sufficient information to infer \\(\\mathbf{c}\\), \\(\\beta\\) and the keypoints \\(\\mathbf{j}\\). The model distribution can be simplified as:" + }, + { + "type": "equation", + "bbox": [ + 0.182, + 0.743, + 0.469, + 0.759 + ], + "angle": 0, + "content": "\\[\np _ {\\phi} (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta) = p _ {\\phi} (\\theta | I). \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.772, + 0.469, + 0.802 + ], + "angle": 0, + "content": "Based on Eqs. (7) and (8), the KL divergence between the model and data distributions can be expressed as:" + }, + { + "type": "equation", + "bbox": [ + 0.082, + 0.814, + 0.487, + 0.9 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} K L \\left(p _ {\\phi} (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta) \\| p (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta)\\right) = \\\\ - \\left(\\underbrace {\\underbrace {E _ {p _ {\\phi} (\\theta \\mid I)} [ \\log p (\\mathbf {j} \\mid \\mathbf {c} , \\beta , \\theta) ]} _ {\\text {r e c o n s t r u c t i o n}} + \\underbrace {E _ {p _ {\\phi} (\\theta \\mid I)} [ \\log p (\\theta) ]} _ {\\text {p r i o r}} + \\underbrace {H \\left(p _ {\\phi} (\\theta \\mid I)\\right)} _ {\\text {e n t r o p y}}\\right), \\tag {9} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.363, + 0.892, + 0.454 + ], + "angle": 0, + "content": "where \\( H(p_{\\phi}(\\theta |I)) = -E_{p_{\\phi}(\\theta |I)}[\\log p_{\\phi}(\\theta |I)] \\) is the entropy of \\( \\theta \\) given input image \\( I \\). See Suppl. B for the full derivation. Minimizing the KL divergence in Eq. (9) maximizes the reconstruction accuracy and the conditional entropy of the pose under pose prior \\( p(\\theta) \\); this can be used directly to supervise the neural network \\( \\phi \\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.459, + 0.893, + 0.776 + ], + "angle": 0, + "content": "Based on the above derivation, we propose a weakly-supervised multi-hypothesis framework as illustrated in Fig. 2. We consider only visible 2D keypoints as supervisory signals for the reconstruction. Like [21, 26], we assume that visible keypoints follow a Laplace distribution for sharpness. In line with the principle of maximum entropy (Sec. 3.4), the occluded keypoints each follow a uniform distribution of feasible locations. The intuition behind such an assumption is that, for occluded keypoints, we relax the supervision using prior knowledge \\( p(\\theta) \\) to generate feasible solutions for the image. This prevents an overconfident model that tries to fit all labels regardless of visibility and also compensates for the lack of one-to-many data-label pairs. As \\( \\theta \\) is derived from a parametric model, the prior can be applied simply as a uniform distribution [33] or adversarially [16] based on its representation. We choose to model the distribution \\( p_{\\phi}(\\theta |I) \\) using a conditional NF model, i.e., \\( p_{\\phi}(\\theta |I) = \\mathcal{F}^{-1}(\\theta |I) \\), as it is more feasible to calculate the entropy term \\( H(p_{\\phi}(\\theta |I)) \\) via Monte Carlo (MC) sampling. Therefore, all three terms in Eq. (9) can be maximized by MC sampling and SGD [18]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.892, + 0.901 + ], + "angle": 0, + "content": "An important part of our formulation involves the explicit maximization of entropy. The link between entropy and diverse hypotheses is highly intuitive, yet this has been overlooked in previous work. Even without one-to-many labels, the entropy term encourages the model \\(\\phi\\) to generate hypotheses that are diverse; the reconstruction and prior term ensure that the hypotheses respect the observed labels while remaining feasible." + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "14843" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.077, + 0.091, + 0.295, + 0.108 + ], + "angle": 0, + "content": "4.2. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.115, + 0.469, + 0.176 + ], + "angle": 0, + "content": "In Eq. (9), we represent image \\(I\\) with image features extracted from a ResNet-50 [12] backbone. To estimate \\(\\mathbf{c}\\) and \\(\\beta\\), we append a 512-hidden unit MLP to the backbone. For the normalizing flow model, we use the Real NVP[8]." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.176, + 0.469, + 0.238 + ], + "angle": 0, + "content": "First, to obtain \\(\\theta\\) for an image, according to LOTUS, we sample \\(\\mathbf{z}_0\\) from a Gaussian distribution and feed it together with image feature of \\(I\\) to the invertible flow network \\(\\mathcal{F}(\\mathbf{z}|I)\\) (the solid line in the yellow block in Fig. 2)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.258, + 0.469, + 0.305 + ], + "angle": 0, + "content": "Reconstruction. We use a constant scale \\( b \\) for the Laplace and assume the joints do not exceed the large occlusion range (Suppl. B.2); the reconstruction loss simplifies to:" + }, + { + "type": "equation", + "bbox": [ + 0.188, + 0.317, + 0.469, + 0.358 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {r e c}} = \\sum_ {k = 1} ^ {K} v _ {k} \\| \\mathbf {j} _ {k} - \\hat {\\mathbf {j}} _ {k} \\| _ {1}, \\tag {10}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.37, + 0.469, + 0.415 + ], + "angle": 0, + "content": "where \\(K\\) is the number of joints and \\(\\mathbf{j}_k\\) represents \\(k\\)-th joint; the loss is effective only on visible joints based on visibility indicator \\(v_k\\)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.437, + 0.469, + 0.513 + ], + "angle": 0, + "content": "Prior. To encourage feasible poses, we introduce a prior term \\(\\mathcal{R}(\\cdot)\\) on \\(\\theta\\). For MANO, \\(\\theta\\) is given as PCA coefficients. We empirically place a uniform distribution \\(\\mathcal{R}(\\theta) = \\mathcal{U}(-2,2)\\) on these coefficients, which covers most feasible solutions while avoiding invalid poses [33], i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.177, + 0.525, + 0.469, + 0.555 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\theta} = \\sum_ {i} \\max (0, | \\theta_ {i} | - 2) ^ {2}. \\tag {11}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.568, + 0.469, + 0.599 + ], + "angle": 0, + "content": "For SMPL, \\(\\theta\\) represents axis-angle rotations and can be restricted by an adversarial prior [16], i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.224, + 0.613, + 0.469, + 0.628 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\theta} = \\operatorname {A d v} (\\theta). \\tag {12}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.65, + 0.406, + 0.664 + ], + "angle": 0, + "content": "Entropy. We use a negative log-likelihood loss:" + }, + { + "type": "equation", + "bbox": [ + 0.201, + 0.678, + 0.469, + 0.694 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {H} = - \\log p _ {\\phi} (\\theta | I), \\tag {13}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.707, + 0.469, + 0.768 + ], + "angle": 0, + "content": "where \\(\\theta\\) is sampled from the normalizing flow. The reverse path of the NF, \\(\\mathcal{F}^{-1}(\\theta |I)\\), maps \\(\\theta\\) back to \\(\\mathbf{z}_0\\) in the latent space conditional on the image features to compute Eq. (4) [8, 17] (dashed lines in the yellow block in Fig. 2)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.769, + 0.468, + 0.813 + ], + "angle": 0, + "content": "The losses in Eqs. (10)-(13) each covers a term in Eq. (9). With the \\(\\beta\\) regularization in Eq. (2), all losses sum into the final training objective:" + }, + { + "type": "equation", + "bbox": [ + 0.138, + 0.832, + 0.468, + 0.847 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} = \\lambda_ {\\text {r e c}} \\mathcal {L} _ {\\text {r e c}} + \\lambda_ {\\theta} \\mathcal {L} _ {\\theta} + \\lambda_ {H} \\mathcal {L} _ {H} + \\lambda_ {\\beta} \\mathcal {L} _ {\\beta}, \\tag {14}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.469, + 0.901 + ], + "angle": 0, + "content": "where the \\(\\lambda\\)s are the trade-off hyperparameters and \\(\\mathcal{L}_{\\beta} = ||\\beta||_2^2\\). See Suppl. B for the full derivations and more training details." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.091, + 0.632, + 0.108 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.115, + 0.768, + 0.13 + ], + "angle": 0, + "content": "5.1. Datasets, Metrics, & Baselines" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.138, + 0.892, + 0.244 + ], + "angle": 0, + "content": "Datasets. We synthesize a 2-joint toy setting in 2D to highlight components of our model. For the human body, we experiment on Human3.6M (H36M) [14] and its ambiguous version AH36M [2] with randomly truncated images of H36M to hide keypoints. Following [2, 21], we train with subjects S1 and S5-9 and test with S11, training with H36M and AH36M jointly, while evaluating separately." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.244, + 0.892, + 0.426 + ], + "angle": 0, + "content": "Inspired by AH36M, we construct Ambiguous RHD (ARHD) from the synthetic hand pose dataset RHD [43] by adding circular patches with a predefined radius to the fingers' DIP joints1. The visibility in the scene is affected depending on the finger and circle radius (see Fig. 5(c)). We also use HO3D [11], a real-world hand-object dataset that features severe occlusions. To evaluate the multi-hypothesis metrics, similar to previous work [38], we split a test subset from the training dataset. We estimate the visibility of a joint [9] by thresholding the difference between captured surface depth and the true keypoint position. More details of the datasets are provided in Suppl. D." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.443, + 0.891, + 0.503 + ], + "angle": 0, + "content": "Evaluation Metrics. Mean End-Point Error (EPE) is the average Euclidean distance between predicted and ground-truth joints, from which we consider the Best Hypothesis (BH) [25, 2] and our newly proposed All Hypothesis (AH)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.504, + 0.891, + 0.578 + ], + "angle": 0, + "content": "BH is a standard multi-hypothesis metric that selects the hypothesis with the lowest pose or mesh EPE. To evaluate the accuracy of all hypotheses, we propose AH, which is the mean EPE of all hypotheses on 2D visible joints to measure consistency to the image evidence." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.579, + 0.892, + 0.699 + ], + "angle": 0, + "content": "As we highlighted, multiple hypotheses should be diverse, but the diversity should only be on uncertain joints e.g. under occlusion. However, existing BH and diversity metrics [34, 26] do not capture this target because undesirable diversity on the visible joints may also contribute to the diversity metrics. Therefore, we propose to complement the evaluation of multi-hypothesis methods with Per-Joint Diversity (PJD) and a Relative Diversity (RD) ratio." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.7, + 0.892, + 0.76 + ], + "angle": 0, + "content": "PJD measures the standard deviation per joint and can be used to show the diversity of both visible and occluded joints in 2D and 3D spaces. To highlight the source of diversity, we propose a ratio:" + }, + { + "type": "equation", + "bbox": [ + 0.637, + 0.766, + 0.89, + 0.799 + ], + "angle": 0, + "content": "\\[\n\\mathbf {R D} = \\frac {\\mathrm {P J D} _ {2 \\mathrm {d v i s}}}{\\mathrm {P J D} _ {3 \\mathrm {d o c c}}}, \\tag {15}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.804, + 0.892, + 0.88 + ], + "angle": 0, + "content": "to account for the diversity of both the certain (i.e., 2D visible keypoints) and the uncertain parts (i.e., 3D occluded keypoints). A lower RD means more diversity on the occluded keypoints relative to visible keypoints. We follow [35, 37] and sample 200 hypotheses for evaluation." + }, + { + "type": "page_footnote", + "bbox": [ + 0.518, + 0.887, + 0.89, + 0.901 + ], + "angle": 0, + "content": "1The distal interphalangeal (DIP) joint is the one closest to the fingertip." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "14844" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.087, + 0.092, + 0.229, + 0.173 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.147, + 0.177, + 0.167, + 0.188 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "image", + "bbox": [ + 0.23, + 0.092, + 0.351, + 0.173 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.275, + 0.177, + 0.294, + 0.189 + ], + "angle": 0, + "content": "(b)" + }, + { + "type": "image", + "bbox": [ + 0.353, + 0.092, + 0.457, + 0.173 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.395, + 0.177, + 0.413, + 0.189 + ], + "angle": 0, + "content": "(c)" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.191, + 0.47, + 0.26 + ], + "angle": 0, + "content": "Figure 3. (a) Toy problem setting featuring four modes. (b) Our probabilistic method in a weakly supervised setting recovers all the modes. (c) The deterministic method, even under strong supervision, predicts wrong modes as it easily overfits ubiquitous observation noise." + }, + { + "type": "image", + "bbox": [ + 0.088, + 0.274, + 0.219, + 0.429 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.157, + 0.433, + 0.176, + 0.445 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "image", + "bbox": [ + 0.22, + 0.275, + 0.339, + 0.429 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.277, + 0.433, + 0.297, + 0.445 + ], + "angle": 0, + "content": "(b)" + }, + { + "type": "image", + "bbox": [ + 0.339, + 0.275, + 0.464, + 0.429 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.4, + 0.433, + 0.419, + 0.445 + ], + "angle": 0, + "content": "(c)" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.448, + 0.47, + 0.517 + ], + "angle": 0, + "content": "Figure 4. (a) Lowering the weight of the entropy term can impair multi-mode learning while (b) increasing the weights hurts the fitting accuracy, although it achieves diversity. (c) Choosing different feasibility priors will also make the final learned modes different. The second row shows the mode distribution in \\(\\alpha\\) space." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.544, + 0.469, + 0.666 + ], + "angle": 0, + "content": "Baselines & SOTAs. We compare our method with two deterministic methods, Det (2D Vis) and Det (3D), which use visible 2D and all 3D keypoint positions as supervision, respectively. For more details, refer to a similar pipeline in [3]. Moreover, we compare our method with the state-of-the-art multi-hypothesis methods, including MDN [25], conditional VAE [35], Multi-bodies [2], ProHMR [21], CM-VAE [36] and WS3DPG [26]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.667, + 0.47, + 0.756 + ], + "angle": 0, + "content": "Some of these approaches are designed with 3D pose supervision; we replace their corresponding supervised losses with the 2D version in Eq. (2). Unless specified, we also use visibility labels as weights while remaining as faithful as possible to the original method. See Suppl. F for method introductions and details." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.77, + 0.396, + 0.787 + ], + "angle": 0, + "content": "5.2. Toy Experiments & Ablation Studies" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Settings. We perform the toy experiment under a simple setting (depth ambiguity), as shown in Fig. 3(a). Consider a single chain with two keypoints plus a root keypoint. The bones are fixed to length 1 and the root is at the origin. The data \\((\\mathbf{y},\\alpha)\\) consists of the 1D projection \\(y_{k}\\) of the keypoint on the y-axis and the angle \\(\\alpha_{k}\\) between the chain and the y-axis. From \\(\\alpha_{k}\\), we can get 2D coordinates" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.213 + ], + "angle": 0, + "content": "\\(\\mathbf{j}_k = (\\sin \\alpha_k, \\cos \\alpha_k)\\) relative to their parent. There are in total four Gaussian modes for the complete data, i.e., each joint can swing left and right. The model is trained to predict \\(\\alpha\\) based on \\(\\mathbf{y}\\). For weak supervision, only 1D projections \\(\\mathbf{y}\\) are given. For strong supervision, all 2D coordinates \\(\\mathbf{j}\\) are provided. Our model uses an MLP and Real NVP as the backbone and optimizes an objective similar to Eq. (14). For the prior loss, we add an \\(L_2\\) norm constraint on \\(\\alpha\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.235, + 0.892, + 0.342 + ], + "angle": 0, + "content": "Deterministic vs. Multi-Hypothesis. The deterministic model trained under both weak and strong supervision can learn only one of the four modes. Moreover, under strong supervision, it is sensitive to similar input data and predicts wrong modes if the inputs are corrupted with small perturbations (Fig. 3(c)). In contrast, existing multi-hypothesis methods can recover all modes under strong supervision." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.365, + 0.892, + 0.456 + ], + "angle": 0, + "content": "Ours vs. Existing Multi-Hypothesis Methods. Existing methods require similar observations with multiple distinct ground-truth poses. In the weakly supervised setting, we compare with MDN and observe that it finds only one of the modes (Suppl. G.1) while our proposed method can successfully recover all the modes (Fig. 3(b))." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.479, + 0.892, + 0.616 + ], + "angle": 0, + "content": "Reconstruction vs. Entropy. The entropy term encourages the set of predictions to cover diverse solutions while maintaining a low reconstruction error. As the weight of the entropy term \\(\\lambda_{H}\\) decreases, the objective emphasizes reconstruction at the cost of entropy, leading to missed modes (Fig. 4(a)). The extreme is the degradation to a deterministic model. On the other hand, with the increase in \\(\\lambda_{H}\\), the model pays less attention to reconstructing observed evidence, hence the modes become dispersed (Fig. 4(b))." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.638, + 0.892, + 0.79 + ], + "angle": 0, + "content": "Angle Prior. The prior term determines the distribution over the feasible solution space. When we lower the weight of the prior loss, the model may fit the evidence better but consider less feasible poses. On the other hand, prior knowledge defines the solution space, and the entropy term will encourage the predictions to cover all possible solutions based on the prior. For example, when we add a prior \\(\\sin \\alpha_{k} \\geq 0\\) for the top keypoints, some previous modes become infeasible and the model will only find two of the four original poses (Fig. 4(c))." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.801, + 0.746, + 0.817 + ], + "angle": 0, + "content": "5.3. Synthetic Ambiguous RHD" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Deterministic vs. Multi-Hypothesis. Table 1(a) shows that on ARHD, all the multi-hypothesis methods [25, 35, 26, 21, 37] outperform the deterministic 'Det (2D Vis)' on the BH metric. Some methods even outperform the 'Det (3D)' baseline with 3D supervision." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "14845" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.089, + 0.089, + 0.885, + 0.254 + ], + "angle": 0, + "content": "
ARHDHO3D
BH (mm)↓ JointAH (pix)↓PJDRD↓BH (mm)↓ JointAH (pix)↓PJDRD↓
2D Vis3D Occ2D Vis3D Occ
Det (3D) [44]20.98----23.8825.18---
Det (2D Vis)25.1114.39---24.1025.4016.85--
Multi-bodies [2]20.5215.763.505.980.5922.0723.5619.571.920.62
MDN [25]21.3318.477.1412.690.5621.2822.6718.813.480.56
CVAE [35]20.9919.957.0210.660.6621.0422.6218.904.070.61
ProHMR [21]24.4413.370.130.220.5924.0525.4117.190.160.64
CM-VAE [36]21.9916.595.6710.400.5522.2023.5418.394.940.57
WS3DPG [26]24.3417.794.617.390.6223.6724.9918.343.060.65
Ours20.3513.423.8614.420.2720.5521.8316.953.300.28
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.255, + 0.893, + 0.283 + ], + "angle": 0, + "content": "Table 1. Quantitative results on ARHD and HO3D V3. The best is marked in bold; the second best is underlined. Our method achieves competitive SOTA results; occluded keypoints are diverse while visible ones are relatively accurate, i.e., have a lower RD." + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.306, + 0.331, + 0.455 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.107, + 0.461, + 0.314, + 0.474 + ], + "angle": 0, + "content": "(a) RD: 2D Vis PJD - 3D Occ PJD" + }, + { + "type": "image", + "bbox": [ + 0.327, + 0.306, + 0.589, + 0.457 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.387, + 0.461, + 0.568, + 0.474 + ], + "angle": 0, + "content": "(b) PJD Curve Along Training" + }, + { + "type": "image", + "bbox": [ + 0.597, + 0.303, + 0.888, + 0.452 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.684, + 0.461, + 0.818, + 0.474 + ], + "angle": 0, + "content": "(c) Qualitative Results" + }, + { + "type": "image_caption", + "bbox": [ + 0.075, + 0.489, + 0.895, + 0.561 + ], + "angle": 0, + "content": "Figure 5. Illustration on ARHD. (a) Deviation from the diagonal (dashed line) towards the lower-right indicates a better trade-off between the 2D visible accuracy and 3D occluded diversity. (b) Comparison of PJD during learning for occluded (solid line) and visible (dashed line) keypoints. Our approach has a descending trend for visible keypoints and an ascending trend for the occluded ones. (c) Multi-hypothesis meshes. The red boxes highlight the concerned occluded keypoints. Our method predicts diverse and feasible poses under occlusion while MDN's predictions are inconsistent with image evidence on visible keypoints." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.584, + 0.47, + 0.734 + ], + "angle": 0, + "content": "Comparisons with SOTA. Methods like MDN [25] and CVAE [35] all have low BH (Tab. 1(a)). However, their diversity (PJD) for visible and occluded keypoints is high, i.e., the entire hand is diverse. Together with a large AH, this suggests that their hypotheses as a whole do not fit the image evidence well. ProHMR [21] degenerates to an almost deterministic method, and has the lowest PJD for visible and occluded keypoints. We speculate that it is because of its reliance on the strong supervision for \\(\\theta\\) labels. More comparisons can be found in Sec. 5.5." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.737, + 0.471, + 0.827 + ], + "angle": 0, + "content": "In contrast, our framework obtains lower BH and AH and higher occluded diversity (higher \\(\\mathrm{PJD}_{\\mathrm{occ}}\\) and thus significantly lower RD). Fig. 5(a) shows that we strike a good balance between reconstruction and diversity; qualitatively, Fig. 5(c) shows that our recovered meshes are diverse and consistent with the observation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Connection to Existing Works & Ablation Studies. ProHMR [21], CM-VAE [36], and WS3DPG [26] are closely related to our method. Among them, ProHMR" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.584, + 0.892, + 0.751 + ], + "angle": 0, + "content": "is a variant without entropy optimization; CM-VAE [36] applies a single Gaussian distribution instead of our NF; WS3DPG [26] uses a GAN whose entropy is intractable. Tab. 1(a) shows that our entropy term increases the PJD significantly, especially for occluded joints in 3D (ProHMR's 0.22 vs. our 14.42). Moreover, we outperform CM-VAE and WS3DPG on all metrics on ARHD, showing the powerful ability of NFs to model complex distributions and estimate entropy. Additional ablations on visibility in Suppl. G.2 shows that adding additional supervision on occluded joints hurts diversity." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.893, + 0.901 + ], + "angle": 0, + "content": "PJD During Training. Fig. 5(b) shows the test PJD scores throughout training. The PJD of MDN [25] for both visible and occluded keypoints decreases as training progresses. Meanwhile, CVAE [35] has the opposite trend, with increasing PJD scores for both types of keypoints. In contrast, our approach has a descending trend on the PJD of visible keypoints and an ascending trend on the occluded ones (Tab. 1(a))." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.52, + 0.957 + ], + "angle": 0, + "content": "14846" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.092, + 0.462, + 0.199 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.216, + 0.442, + 0.23 + ], + "angle": 0, + "content": "Figure 6. Visualization of our multiple hypotheses on HO3D." + }, + { + "type": "image", + "bbox": [ + 0.078, + 0.246, + 0.465, + 0.34 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.364, + 0.47, + 0.407 + ], + "angle": 0, + "content": "Figure 7. Visualization of hypotheses with the smallest and largest HOI Chamfer distance in two views. Differences are highlighted with red boxes. Hypothesis selection leads to more feasible grasps." + }, + { + "type": "image", + "bbox": [ + 0.079, + 0.42, + 0.465, + 0.55 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.573, + 0.47, + 0.616 + ], + "angle": 0, + "content": "Figure 8. Qualitative results on AH36M. The legs of our hypotheses are much more diverse, while all trunks are consistent with the image. The green mesh is the ground-truth." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.641, + 0.308, + 0.656 + ], + "angle": 0, + "content": "5.4. Real-World Data: HO3D" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.665, + 0.47, + 0.742 + ], + "angle": 0, + "content": "When faced with real-world ambiguous settings, such as objects occluding hands, our method is state-of-the-art compared to other multi-hypothesis methods. The results in Tab. 1(b) and Fig. 6 are consistent with the trends on the synthetic ARHD – our method has the lowest BH and RD." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Hypothesis Selection. With additional input information, the multiple hypotheses can be filtered for an improved set of solutions. We show an example of hypothesis selection in which we select feasible grasps based on the object interaction. We simply use a post-processing strategy to select samples. Specifically, we use a hand-object interaction (HOI) feasibility metric, e.g., the widely used Chamfer distance [4]. Based on the value of the Chamfer distance, we can select hypotheses. We found it useful for picking" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.894, + 0.184 + ], + "angle": 0, + "content": "more plausible poses from hypotheses using task-related constraints. We visualize hypotheses with the lowest and highest HOI Chamfer distance in Fig. 7. Our hypotheses are all consistent with the image cues in the front camera view. From a different view, by incorporating the HOI constraint for hypotheses, we can select more feasible grasp poses." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.202, + 0.893, + 0.354 + ], + "angle": 0, + "content": "Meaningful Diversity. The purpose of our method is to encourage meaningful diversity; hence we treat visible and occluded joints differently. The quality of diversity can be further improved by incorporating more information about the observed ambiguity. One example is to add mask information about the occlusions; it can be incorporated into our framework as a post-hoc hypothesis selection during inference or as a reconstruction loss in Eq. (9) during training. In both ways, the error rate for out-of-occlusion can therefore be reduced without much loss in diversity (Suppl. G.2)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.363, + 0.828, + 0.379 + ], + "angle": 0, + "content": "5.5. State-of-The-Art on H36M & AH36M" + }, + { + "type": "table", + "bbox": [ + 0.526, + 0.397, + 0.869, + 0.549 + ], + "angle": 0, + "content": "
SupervisionMHH36MAH36M
2D VisHMR67.485.2
ProHMR✓64.382.6
Ours✓51.366.4
3DHMR56.8-
SPIN41.1-
MDN✓42.769.5
CVAE✓46.275.1
Multi-bodies✓42.264.2
ProHMR✓36.860.1
Ours✓36.850.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.549, + 0.892, + 0.591 + ], + "angle": 0, + "content": "Table 2. PA-MPJPE (mm) of BH results on H36M and its ambiguous version AH36M under the supervision of visible 2D keypoints (2D Vis) and 3D keypoints (3D) with \\( n = 25 \\)." + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.618, + 0.892, + 0.701 + ], + "angle": 0, + "content": "
SupervisionAH (pix)↓PJDRD↓
2D Vis3D Occ
2D VisProHMR10.920.060.260.23
Ours9.754.5664.050.07
3DProHMR13.383.9824.270.16
Ours10.734.2347.950.09
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.704, + 0.892, + 0.733 + ], + "angle": 0, + "content": "Table 3. Diversity metrics on AH36M under the supervision of visible 2D keypoints (2D Vis) and 3D keypoints (3D)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.892, + 0.856 + ], + "angle": 0, + "content": "Our framework is also effective for human pose estimation. We follow [2, 21] and evaluate the accuracy and diversity of hypotheses on the benchmark H36M and its ambiguous version AH36M. Besides using 2D visible keypoints as supervision, we also test a variant using 3D keypoints. For supervision with 3D keypoints, we follow ProHMR [21] and supervise the predicted 3D poses from SMPL directly." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Tab. 2 shows that we achieve the best BH on both datasets with different supervision settings. Our method has an impressive \\(9.5\\mathrm{mm}\\) improvement on AH36M with 3D" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "14847" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.184 + ], + "angle": 0, + "content": "keypoints as labels; furthermore, our performance with 2D visible keypoints as weak labels is comparable to using 3D keypoints as labels. Comparing diversity metrics in Tab. 3 and Fig. 8, we outperform ProHMR with respect to AH and RD. Our method with the entropy term predicts highly diverse results in the weakly-supervised setting." + }, + { + "type": "table", + "bbox": [ + 0.132, + 0.197, + 0.418, + 0.254 + ], + "angle": 0, + "content": "
H36MAH36M
Multi-ViewFittingFitting
ProHMR34.534.861.4
Ours34.234.453.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.254, + 0.472, + 0.31 + ], + "angle": 0, + "content": "Table 4. PA-MPJPE (mm) of downstream tasks multi-view refinement and fitting humans with 2D ground-truth. For these tasks, a trained model distribution outputs only one hypothesis by observing more evidence." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.351, + 0.47, + 0.457 + ], + "angle": 0, + "content": "Downstream Tasks. Our method, by estimating an accurate yet diverse set of hypotheses, excels at providing inputs for downstream tasks. We verify the hypotheses through multi-view refinement and fitting humans with 2D ground-truth on H36M and AH36M. We follow ProHMR to find the solution that best matches the evidence among many possible hypotheses by optimization, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.181, + 0.472, + 0.469, + 0.493 + ], + "angle": 0, + "content": "\\[\n\\max _ {\\theta} \\log p _ {\\phi} (\\theta | I) + c (\\theta | \\mathbf {e}), \\tag {16}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.507, + 0.47, + 0.584 + ], + "angle": 0, + "content": "where \\( c(\\theta | \\mathbf{e}) \\) is consistency with additional information, e.g., multi-view and 2D projection consistency. Lower PA-MPJPE in Tab. 4 verifies our effectiveness, which may imply ours obtains a better representation with a more accurate distribution than ProHMR." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.601, + 0.312, + 0.618 + ], + "angle": 0, + "content": "6. Discussion & Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.628, + 0.47, + 0.764 + ], + "angle": 0, + "content": "Our proposed multi-hypothesis framework is flexible, efficient, and label-friendly. We emphasize that diversity in the hypotheses should not be arbitrary; instead, it should come from ambiguity present in the image itself. To that end, we also propose a more comprehensive evaluation scheme based on visibility. In our work, we have only considered ambiguity from object occlusions and image truncations, but additional factors such as image quality and light are interesting directions to investigate for future work." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.902 + ], + "angle": 0, + "content": "We note that by virtue of evaluating on the provided annotations of the current datasets, the diversity concept remains vague and limited to the dataset. For instance, in-distribution testing aims to learn the pose diversity captured in that dataset. It may not require learning more diverse outdoor poses to achieve a good BH on indoor datasets and thus not conducive to generalization to other scenarios. It is suggested to focus more on the improvement and evaluation of the diversity in the generalization scenario." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.183 + ], + "angle": 0, + "content": "Acknowledgments. This research/project is supported by the Ministry of Education, Singapore, under its MOE Academic Research Fund Tier 2 (STEM RIE2025 MOET2EP20220-0015). We would also like to thank the ACs, reviewers, Dr. Chen Li, and Junpeng Hu for their valuable suggestions." + }, + { + "type": "title", + "bbox": [ + 0.502, + 0.196, + 0.597, + 0.211 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.22, + 0.892, + 0.276 + ], + "angle": 0, + "content": "[1] Mahmoud Assran, Mathilde Caron, Ishan Misra, Piotr Bojanowski, Florian Bordes, Pascal Vincent, Armand Joulin, Mike Rabbat, and Nicolas Ballas. Masked siamese networks for label-efficient learning. In ECCV, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.277, + 0.892, + 0.332 + ], + "angle": 0, + "content": "[2] Benjamin Biggs, David Novotny, Sebastien Ehrhardt, Hanbyul Joo, Ben Graham, and Andrea Vedaldi. 3D Multibodies: Fitting sets of plausible 3D human models to ambiguous image data. In NeurIPS, 2020. 1, 2, 4, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.334, + 0.892, + 0.375 + ], + "angle": 0, + "content": "[3] Adnane Boukhayma, Rodrigo de Bem, and Philip HS Torr. 3D hand shape and pose from images in the wild. In CVPR, 2019. 1, 2, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.377, + 0.892, + 0.417 + ], + "angle": 0, + "content": "[4] Zhe Cao, Ilija Radosavovic, Angjoo Kanazawa, and Jitendra Malik. Reconstructing hand-object interactions in the wild. In ICCV, 2021. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.419, + 0.892, + 0.474 + ], + "angle": 0, + "content": "[5] Ping Chen, Yujin Chen, Dong Yang, Fangyin Wu, Qin Li, Qingpei Xia, and Yong Tan. I2UV-HandNet: Image-to-UV prediction network for accurate and high-fidelity 3D hand mesh modeling. In ICCV, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.476, + 0.892, + 0.517 + ], + "angle": 0, + "content": "[6] Zerui Chen, Yana Hasson, Cordelia Schmid, and Ivan Laptev. AlignSDF: Pose-aligned signed distance fields for hand-object reconstruction. In ECCV, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.518, + 0.892, + 0.572 + ], + "angle": 0, + "content": "[7] Hongsuk Choi, Gyeongsik Moon, and Kyoung Mu Lee. Pose2Mesh: Graph convolutional network for 3D human pose and mesh recovery from a 2D human pose. In ECCV, 2020. 1, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.575, + 0.892, + 0.602 + ], + "angle": 0, + "content": "[8] Laurent Dinh, Jascha Sohl-Dickstein, and Samy Bengio. Density estimation using real NVP. In ICLR, 2017. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.604, + 0.892, + 0.631 + ], + "angle": 0, + "content": "[9] Kerui Gu, Linlin Yang, and Angela Yao. Removing the bias of integral pose regression. In ICCV, 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.633, + 0.892, + 0.66 + ], + "angle": 0, + "content": "[10] Silviu Guiasu and Abe Shenitzer. The principle of maximum entropy. Math. Intell., 7(1):42-48, 1985. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.661, + 0.892, + 0.702 + ], + "angle": 0, + "content": "[11] Shreyas Hampali, Mahdi Rad, Markus Oberweger, and Vincent Lepetit. HOnnotate: A method for 3D annotation of hand and object poses. In CVPR, 2020. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.704, + 0.892, + 0.745 + ], + "angle": 0, + "content": "[12] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, 2016. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.747, + 0.892, + 0.801 + ], + "angle": 0, + "content": "[13] R Devon Hjelm, Alex Fedorov, Samuel Lavoie-Marchildon, Karan Grewal, Phil Bachman, Adam Trischler, and Yoshua Bengio. Learning deep representations by mutual information estimation and maximization. In ICLR, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.803, + 0.892, + 0.857 + ], + "angle": 0, + "content": "[14] Catalin Ionescu, Dragos Papava, Vlad Olaru, and Cristian Sminchisescu. Human3.6M: Large scale datasets and predictive methods for 3D human sensing in natural environments. TPAMI, 36(7):1325-1339, 2013. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.859, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[15] Umar Iqbal, Pavlo Molchanov, Thomas Breuel Juergen Gall, and Jan Kautz. Hand pose estimation via latent 2.5D heatmap regression. In ECCV, 2018. 1" + }, + { + "type": "list", + "bbox": [ + 0.502, + 0.22, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "14848" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.134 + ], + "angle": 0, + "content": "[16] Angjoo Kanazawa, Michael J Black, David W Jacobs, and Jitendra Malik. End-to-end recovery of human shape and pose. In CVPR, 2018. 2, 3, 4, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.47, + 0.163 + ], + "angle": 0, + "content": "[17] Durk P Kingma and Prafulla Dhariwal. Glow: Generative flow with invertible 1x1 convolutions. In NeurIPS, 2018. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.165, + 0.469, + 0.192 + ], + "angle": 0, + "content": "[18] Diederik P. Kingma and Max Welling. Auto-encoding variational Bayes. In ICLR, 2014. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.194, + 0.469, + 0.234 + ], + "angle": 0, + "content": "[19] Muhammed Kocabas, Nikos Athanasiou, and Michael J Black. VIBE: Video inference for human body pose and shape estimation. In CVPR, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.236, + 0.469, + 0.277 + ], + "angle": 0, + "content": "[20] Nikos Kolotouros, Georgios Pavlakos, Michael J Black, and Kostas Daniilidis. Learning to reconstruct 3D human pose and shape via model-fitting in the loop. In ICCV, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.279, + 0.469, + 0.32 + ], + "angle": 0, + "content": "[21] Nikos Kolotouros, Georgios Pavlakos, Dinesh Jayaraman, and Kostas Daniilidis. Probabilistic modeling for human mesh recovery. In ICCV, 2021. 1, 2, 4, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.322, + 0.469, + 0.376 + ], + "angle": 0, + "content": "[22] Dominik Kulon, Riza Alp Guler, Iasonas Kokkinos, Michael M Bronstein, and Stefanos Zafeiriou. Weakly-supervised mesh-convolutional hand reconstruction in the wild. In CVPR, 2020. 2, 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.378, + 0.469, + 0.432 + ], + "angle": 0, + "content": "[23] Rithesh Kumar, Sherjil Ozair, Anirudh Goyal, Aaron Courville, and Yoshua Bengio. Maximum entropy generators for energy-based models. In arXiv:1901.08508, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.434, + 0.469, + 0.489 + ], + "angle": 0, + "content": "[24] Jogendra Nath Kundu, Siddharth Seth, Pradyumna YM, Varun Jampani, Anirban Chakraborty, and R Venkatesh Babu. Uncertainty-aware adaptation for self-supervised 3d human pose estimation. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.491, + 0.469, + 0.532 + ], + "angle": 0, + "content": "[25] Chen Li and Gim Hee Lee. Generating multiple hypotheses for 3D human pose estimation with mixture density network. In CVPR, 2019. 1, 2, 3, 4, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.534, + 0.469, + 0.574 + ], + "angle": 0, + "content": "[26] Chen Li and Gim Hee Lee. Weakly supervised generative network for multiple 3D human pose hypotheses. In BMVC, 2020. 1, 3, 4, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.576, + 0.469, + 0.617 + ], + "angle": 0, + "content": "[27] Wenhao Li, Hong Liu, Hao Tang, Pichao Wang, and Luc Van Gool. MHFormer: Multi-hypothesis transformer for 3D human pose estimation. In CVPR, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.619, + 0.469, + 0.659 + ], + "angle": 0, + "content": "[28] Kevin Lin, Lijuan Wang, and Zicheng Liu. End-to-end human pose and mesh reconstruction with transformers. In CVPR, 2021. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.661, + 0.469, + 0.702 + ], + "angle": 0, + "content": "[29] Xin Liu, Zhongdao Wang, Ya-Li Li, and Shengjin Wang. Self-supervised learning via maximum entropy coding. 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.704, + 0.469, + 0.746 + ], + "angle": 0, + "content": "[30] Matthew Loper, Naureen Mahmood, Javier Romero, Gerard Pons-Moll, and Michael J Black. SMPL: A skinned multiperson linear model. TOG, 34(6):1-16, 2015. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.747, + 0.469, + 0.801 + ], + "angle": 0, + "content": "[31] Gyeongsik Moon and Kyoung Mu Lee. I2L-MeshNet: Image-to-lixel prediction network for accurate 3D human pose and mesh estimation from a single RGB image. In ECCV, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.804, + 0.469, + 0.858 + ], + "angle": 0, + "content": "[32] George Papamakarios, Eric T Nalisnick, Danilo Jimenez Rezende, Shakir Mohamed, and Balaji Lakshminarayanan. Normalizing flows for probabilistic modeling and inference. JMLR, 22(57):1-64, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.86, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[33] Javier Romero, Dimitrios Tzionas, and Michael J. Black. Embodied Hands: Modeling and capturing hands and bodies together. TOG, 36(6):1-17, 2017. 2, 3, 4, 5" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "[34] Akash Sengupta, Ignas Budvytis, and Roberto Cipolla. Hierarchical kinematic probability distributions for 3D human shape and pose estimation from images in the wild. In ICCV, 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.149, + 0.892, + 0.204 + ], + "angle": 0, + "content": "[35] Saurabh Sharma, Pavan Teja Varigonda, Prashast Bindal, Abhishek Sharma, and Arjun Jain. Monocular 3D human pose estimation by generation and ordinal ranking. In ICCV, 2019. 1, 2, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.206, + 0.892, + 0.247 + ], + "angle": 0, + "content": "[36] Adrian Spurr, Jie Song, Seonwook Park, and Otmar Hilliges. Cross-modal deep variational hand pose estimation. In CVPR, 2018. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.249, + 0.892, + 0.29 + ], + "angle": 0, + "content": "[37] Tom Wehrbein, Marco Rudolph, Bodo Rosenhahn, and Bastian Wandt. Probabilistic monocular 3D human pose estimation with normalizing flows. In ICCV, 2021. 1, 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.292, + 0.892, + 0.333 + ], + "angle": 0, + "content": "[38] Lixin Yang, Xinyu Zhan, Kailin Li, Wenqiang Xu, Jiefeng Li, and Cewu Lu. CPF: Learning a contact potential field to model the hand-object interaction. In ICCV, 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.335, + 0.892, + 0.375 + ], + "angle": 0, + "content": "[39] Qi Ye and Tae-Kyun Kim. Occlusion-aware hand pose estimation using hierarchical mixture density network. In ECCV, 2018. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.377, + 0.892, + 0.418 + ], + "angle": 0, + "content": "[40] Ziwei Yu, Linlin Yang, You Xie, Ping Chen, and Angela Yao. UV-based 3D hand-object reconstruction with grasp optimization. In BMVC, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.42, + 0.892, + 0.475 + ], + "angle": 0, + "content": "[41] Andrei Zanfir, Eduard Gabriel Bazavan, Hongyi Xu, William T Freeman, Rahul Sukthankar, and Cristian Sminchisescu. Weakly supervised 3D human pose and shape reconstruction with normalizing flows. In ECCV, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.477, + 0.892, + 0.518 + ], + "angle": 0, + "content": "[42] Wang Zeng, Wanli Ouyang, Ping Luo, Wentao Liu, and Xiaogang Wang. 3D human mesh regression with dense correspondence. In CVPR, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.52, + 0.892, + 0.559 + ], + "angle": 0, + "content": "[43] Christian Zimmermann and Thomas Brox. Learning to estimate 3D hand pose from single RGB images. In ICCV, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.562, + 0.892, + 0.617 + ], + "angle": 0, + "content": "[44] Christian Zimmermann, Duygu Ceylan, Jimei Yang, Bryan Russell, Max Argus, and Thomas Brox. FreiHAND: A dataset for markerless capture of hand pose and shape from single RGB images. In ICCV, 2019. 7" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.617 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "14849" + } + ] +] \ No newline at end of file diff --git a/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/f9c54455-f324-48c7-9865-4e8d15caf336_origin.pdf b/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/f9c54455-f324-48c7-9865-4e8d15caf336_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..4b8482061110a2c69def3731f2e5663060518328 --- /dev/null +++ b/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/f9c54455-f324-48c7-9865-4e8d15caf336_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:347a91aa5dc457e0e7ae2331892e9161de088afb350cbee2c8a60a060781b00f +size 4006304 diff --git a/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/full.md b/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/full.md new file mode 100644 index 0000000000000000000000000000000000000000..e86b9363f7f00f0a269cebc65588ba2031f46e9d --- /dev/null +++ b/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/full.md @@ -0,0 +1,386 @@ +# MHEntropy: Entropy Meets Multiple Hypotheses for Pose and Shape Recovery + +Rongyu Chen* Linlin Yang* Angela Yao National University of Singapore {rchen, yangll, ayao}@comp.nus.edu.sg + +# Abstract + +For monocular RGB-based 3D pose and shape estimation, multiple solutions are often feasible due to factors like occlusions and truncations. This work presents a multi-hypothesis probabilistic framework by optimizing the Kullback-Leibler divergence (KLD) between the data and model distribution. Our formulation reveals a connection between the pose entropy and diversity in the multiple hypotheses that has been neglected by previous works. For a comprehensive evaluation, besides the best hypothesis (BH) metric, we factor in visibility for evaluating diversity. Additionally, our framework is label-friendly - it can be learned from only partial 2D keypoints, such as visible keypoints. Experiments on both ambiguous and real-world benchmarks demonstrate that our method outperforms other state-of-the-art multi-hypothesis methods. The project page is at https://gloryyrolg.github.io/MHEntropy. + +# 1. Introduction + +Pose and shape estimation is a core component of augmented and virtual reality applications. The majority of monocular 3D pose and shape estimation approaches [28, 31, 7, 3, 15] are designed to predict only a single solution, yet 3D recovery from a monocular input is an inverse problem. Multiple solutions are feasible, especially under settings with occlusions, truncations, low image quality, or other ambiguities. It is therefore meaningful and desirable to make multi-hypothesis predictions. Multiple hypotheses are also useful in downstream tasks such as 2D keypoint fitting [21] and multi-view fusion [21, 25]. + +Previous multi-hypothesis works use various 2D [2, 21, 37], 3D [39, 25, 2, 21, 37, 35], and mesh [2] reconstruction losses to facilitate kinematically feasible poses and shapes, while encouraging diversity in the solution set. Yet the learning and evaluation for multi-hypothesis works are underdeveloped. Learning-wise, many existing works are not label-friendly and often require one-to-many labeled data to + +![](images/258c6c837eb60aac6fbe5c41b5378260feca4df7befe2ec9f66624b76f27cc1b.jpg) +(a) Occluded Input + +![](images/333fac67ee15126e3d89ff441679c070e2c844b5f93798fd24154b4e88bc8f48.jpg) +(b) Visible versus Occluded + +![](images/f6f069c6c20abddaac054f456da55cb3c4a9d3a879f2bb39c37ce72917605888.jpg) +(c) Multiple Hypotheses + +![](images/3721891385bd9b692eae5fb57fc66a60231ff5dd1da61fa597d46d659d2ce8cf.jpg) + +![](images/c554c1e2bff2722f9ba37fef492874895dca1bcbb34e5bd6c7bb07446292ef06.jpg) +Figure 1. Our method estimates diverse and feasible hypotheses for occluded joints while preserving accuracy for visible joints. + +achieve diversity [21, 2, 35, 25], i.e., similar ambiguous observations with multiple distinct ground-truth poses. Such labels are challenging to obtain, especially under occlusion or out-of-view scenarios for which multi-hypothesis predictions are the most meaningful. While empirical efforts have been made to avoid mode collapse while encouraging diversity [26, 27], these methods often do not fully explore the solution space. It is, therefore, non-trivial to achieve feasible and as diverse as possible solutions. + +Evaluation-wise, multi-hypothesis works use the best hypothesis (BH) as the metric of choice [25, 2, 21, 37, 26]. BH measures the closest distance between a hypothesis set and the ground truth. It emphasizes the accuracy of the closest hypothesis while ignoring the set holistically. Few works explicitly and quantitatively evaluate the diversity of the predicted hypotheses. When they do so, diversity is evaluated independently from the input [26]. Yet joints under occlusion or a lack of evidence feature more uncertainty, and as such should correspond to more diversity, while joints should be less diverse on unambiguous parts. Current multi-hypothesis evaluation schemes do not make such distinctions. Unwanted diversity on unambiguous joints also contributes to the calculation of overall diversity. + +This paper addresses these shortcomings and presents a new multi-hypothesis framework for estimating 3D poses and shapes. At the heart of our method is a simple yet essential underlying criterion - hypotheses should be diverse, but meaningfully so, and correlate with an observation's ambiguity (see Fig. 1 (b)). To that end, we take a probabilistically principled approach and minimize the Kullback-Leibler (KL) divergence between the model distribution and the underlying data distribution. Our objective results in three terms: a reconstruction accuracy, a pose prior, and most interestingly, a model entropy term. This additional entropy term echoes the principle of maximum entropy [10], where the probability distribution is designed to align with observations but otherwise be as unbiased as possible. For pose estimation, this means that visible and unambiguous keypoints should remain fixed across the hypotheses, while occluded and ambiguous keypoints should be feasible yet diverse (see Fig. 1 (b) and (c)). + +Unlike existing works [35, 25, 21], our formulation for diversity does not require one-to-many training data. Instead, our model is trained by explicitly encouraging it to explore the feasible solution space via entropy maximization while remaining consistent with the evidence. For the implementation of our framework, we learn a conditional distribution of parameters with a normalizing flow model. The parameters modelled come from parametric 3D models like MANO [33] and SMPL [30]. + +To be label-friendly, we advocate using weak labels; specifically, we recommend 2D keypoints from only visible joints. Using 2D keypoint labels is well established in the literature [3, 22]. However, considering only visible 2D keypoints is not well-studied, even though it is highly intuitive from an annotation point of view and a natural fit for multiple hypotheses. + +For a comprehensive evaluation beyond the best hypothesis we introduce a Per-Joint Diversity (PJD) to measure the diversity of visible and occluded keypoints. Based on PJD, we further propose a Relative Diversity (RD) ratio to measure the reasonable diversity of the hypotheses. A low ratio indicates that observed keypoints are deterministic while occluded keypoints are diverse. In experiments, our method finds highly accurate BH and achieves the best RD ratio compared to other multi-hypothesis approaches. To summarize our contributions, + +- We formulate multi-hypothesis estimation as a minimization of the KL divergence between the model distribution and the data distribution. This formulation is probabilistically principled and naturally yields an entropy term that encourages diversity in the solution set. +- From our KL formulation, we propose a framework to estimate multiple hypotheses of 3D pose and shape that favours feasible and diverse solutions by design. + +- We emphasize visibility in multi-hypothesis frameworks by exploring visible 2D keypoints, i.e. partial weak labels for estimating 3D pose and shape and factoring in visibility for evaluating diversity. +- Experiments on toy, ambiguous, and real-world data demonstrate that our method achieves excellent diversity and the best BH compared to other state-of-the-art multi-hypothesis methods. + +# 2. Related Work + +# 2.1. 3D Human/Hand Pose & Shape Recovery + +Existing works estimate 3D pose and shape either directly [3, 16, 20, 19], or indirectly [5, 28, 31] via a parametric model like SMPL and MANO. Parametric models serve as priors to encourage feasible solutions [3, 16] and reduce the reliance on labels [22, 41]. The parameters of parametric models are typically learned under the supervision of 3D meshes and poses [3, 16, 20, 19]. Without parametric models, works like [42, 5, 28, 31, 22] focus on the representations of 3D surfaces and the design of architectures. They convert the surfaces into different 3D representations like mesh vertices [31, 28], UV mapping [42, 5, 40], and implicit representations [6], and then fit the surfaces based on architectures like GCNs [22] and Transformers [28]. + +# 2.2. Multi-Hypothesis Methods + +These methods predict diverse and feasible predictions from ambiguous input evidence, often via deep generative models. The work in [35] proposes a conditional VAE to model the distribution of a 3D pose sample set that is consistent with the 2D pose, which helps to tackle the inherent ambiguity in 2D-to-3D lifting. MDN-based works [39, 25] introduce mixture density models to estimate multiple hypotheses by minimizing the negative log-likelihood of a multi-modal mixture of Gaussians. + +More recent works [37, 2, 21] apply normalizing flow (NF) models. The work in [2] directly employs NFs as a prior on the distribution of plausible poses at test time. Differently, other works, like [37, 21], propose using a conditional NF. Specifically, [21] uses the conditional NF to model the distribution of SMPL pose parameters conditioned on the 2D image, while [37] adopts predicted 2D keypoints as a condition for the NF and specifically considers 2D poses in the latent space to model the distribution from 3D poses to 2D poses and its reverse. + +Despite their use of probabilistic modeling, few existing works use explicit distributional optimization objectives. Our proposed method is derived directly from KL divergence, which also brings an entropy term and explicitly encourages the estimation of multiple hypotheses. + +# 3. Preliminaries + +# 3.1. Overview of Parametric Models + +MANO [33] and SMPL [30] are commonly-used parametric 3D models for human hands and bodies with pose parameters $\theta \in \mathbb{R}^{N_{\theta}}$ and shape parameters $\beta \in \mathbb{R}^{N_{\beta}}$ . Usually, $\theta$ and $\beta$ are expressed as axis-angle rotations and PCA coefficients learned from pose data and registered shapes, respectively, though $\theta$ can also be expressed as PCA coefficients for MANO. Together, $\theta$ and $\beta$ fully determine the surface mesh $\mathcal{M}(\theta ,\beta)\in \mathbb{R}^{N_m\times 3}$ and joint coordinates $\mathcal{J}(\theta ,\beta)\in \mathbb{R}^{N_j\times 3}$ in the 3D space. + +Given camera parameters $\mathbf{c} = \{R, \mathbf{t}, s\}$ , where $R \in \mathbb{R}^{3 \times 3}$ is a global rotation matrix, $\mathbf{t} \in \mathbb{R}^2$ is the translation, and $s$ is a scaling factor, the 3D pose $\mathcal{J}(\theta, \beta)$ can be projected into 2D joints $\mathbf{j}$ with an orthographic projection $\Pi$ : + +$$ +\mathbf {j} = s \cdot \Pi (R \cdot \mathcal {J} (\theta , \beta)) + \mathbf {t}. \tag {1} +$$ + +# 3.2. 2D Keypoint Supervision + +One weakly-supervised variant of monocular 3D pose and shape estimation is learned from only 2D keypoint annotations. A common approach [3] is to estimate the MANO or SMPL parameters $(\hat{\theta},\hat{\beta})$ for a given image and project the resulting 3D pose back into 2D joints $\hat{\mathbf{j}}$ , as per Eq. (1). The parameters can be learned with ground-truth 2D joints $\mathbf{j}$ by minimizing the following objective: + +$$ +\mathcal {L} = \left\| \mathbf {j} - \hat {\mathbf {j}} \right\| _ {1} + \lambda_ {\theta} \mathcal {R} (\hat {\theta}) + \lambda_ {\beta} \| \hat {\beta} \| _ {2} ^ {2}, \tag {2} +$$ + +featuring a 2D reconstruction loss, a prior term $\mathcal{R}(\cdot)$ on $\theta$ to encourage feasible poses, an $l_{2}$ regularization on $\beta$ , and weighting hyperparameters $\lambda_{\theta}$ and $\lambda_{\beta}$ . The pose prior $\mathcal{R}(\cdot)$ could be adversarial prior for rotation representations [16] or an $l_{2}$ regularization for PCA coefficients [33]. + +# 3.3. Normalizing Flow + +Normalizing Flows [32] are generative models with strong modeling capacity for complex, multi-modal distributions. Let $\mathbf{X}$ denote a $d$ -dimensional random variable under distribution $P(\mathbf{X})$ . The normalizing flow model represents $\mathbf{X}$ as a series of invertible mappings $\{f_l\}_{l=1}^L: \mathbb{R}^d \mapsto \mathbb{R}^d$ on $d$ -dimensional random variable $\mathbf{Z}$ : + +$$ +\mathbf {X} = \mathcal {F} (\mathbf {Z}) = f _ {L} \circ \dots \circ f _ {2} \circ f _ {1} (\mathbf {Z}). \tag {3} +$$ + +Typically, the base distribution $P(\mathbf{Z})$ is simple, e.g., a normal distribution $\mathcal{N}(\mathbf{0},\mathbf{I})$ . By some specially designed structures of flow blocks [8] and the change-of-variable rule [8], we can get the log-probability density of $\mathbf{X}$ as: + +$$ +\log P (\mathbf {X}) = \log P (\mathbf {Z}) - \sum_ {l = 1} ^ {L} \log \left| \det \frac {\partial f _ {l}}{\partial \mathbf {Z} _ {l - 1}} \right|, \tag {4} +$$ + +where, $\mathbf{Z}_l = f_l(\mathbf{Z}_{l-1}), \mathbf{Z}_0 = \mathbf{Z}$ and $\mathbf{Z}_L = \mathbf{X}$ . Normalizing flows estimate the likelihood with the reverse flow $\mathcal{F}^{-1}(\mathbf{X})$ transforming $\mathbf{X}$ to $\mathbf{Z}$ . For sampling, it first samples $\mathbf{z}$ from $P(\mathbf{Z})$ , and passes $\mathbf{z}$ through the flow $\mathcal{F}$ to get $\mathbf{x}$ . Normalizing flows are favoured as generative models because they can tractably estimate the exact likelihood and be optimized through Maximum Likelihood Estimation (MLE). Furthermore, they can also be optimized by sampling through the Law of the Unconscious Statistician (LOTUS). + +# 3.4. Principle of Maximum Entropy + +The entropy of random variable $\mathbf{X}$ taking values in $\mathcal{X}$ , $H(\mathbf{X})$ , quantifies the uncertainty of $\mathbf{X}$ . It is defined as: + +$$ +H (\mathbf {X}) = - \int_ {\mathcal {X}} p (\mathbf {x}) \log p (\mathbf {x}) d \mathbf {x}. \tag {5} +$$ + +Methods such as heuristic objectives [26] and mutual information [13, 23] have been proposed to estimate and optimize entropy. + +Under the principle of maximum entropy [10], the probability distribution that most accurately reflects the current state of the system is the one with the highest entropy. In the context of 3D pose and shape estimation, the distribution should be compatible with complete observations, i.e. visible joints, but otherwise be as unbiased as possible for incomplete or ambiguous observations to maximize the entropy. This prevents unnecessary information from being assumed inadvertently. Especially, entropy maximization has garnered significant attention on efficient learning e.g., self-supervised learning [1, 29] and semi-supervised learning [24]. It is used to remove inadvertent assumptions and encourage the model to explore the full set of prototypes. + +# 4. Methodology + +# 4.1. Framework + +We target multi-hypothesis 3D pose and shape recovery from RGB inputs based on visible 2D keypoints. Consider training instances $\{I, \mathbf{j}, \mathbf{v}\}$ , where $I$ is the RGB image, $\mathbf{j}$ is the corresponding visible 2D keypoints, and $\mathbf{v}$ is an indicator variable for 2D keypoints visibility. In line with previous works [22, 25, 26], we treat the shape parameter $\beta$ and camera parameters $\mathbf{c}$ deterministically and assume that they can be estimated reasonably from $I$ . + +Our main interest then is to model the distribution of the pose parameter $\theta$ , conditioned on the input image $I$ with associated $\mathbf{j}, \beta$ and $\mathbf{c}$ , i.e., the conditional distribution $p(\theta | I, \mathbf{j}, \mathbf{c}, \beta)$ , which we refer to as the data distribution. To model the data distribution, we learn a model $\phi$ in the form of a neural network. Similarly, the model $\phi$ has the distribution $p_{\phi}(\theta | I, \mathbf{j}, \mathbf{c}, \beta)$ , which we term as the model distribution. The model $\phi$ can be learned by minimizing the + +![](images/64d911b38798484e99284aec0d75a3e340b21e6e42b2d9e22c47226a48c044bc.jpg) +Figure 2. Framework overview. The framework is optimized by considering three components: reconstruction, prior, and entropy (see the red double-headed arrows). The distribution of the feasible pose parameters is captured by an NF model conditioned on image features. The reconstruction applies different distributions for the visible keypoints (blue dots) and occluded keypoints (red dots). + +Kullback-Leibler (KL) divergence between the data and the model distribution, i.e., + +$$ +K L \left(p _ {\phi} (\theta | I, \mathbf {j}, \mathbf {c}, \beta) \| p (\theta | I, \mathbf {j}, \mathbf {c}, \beta)\right). \tag {6} +$$ + +Data Distribution. Inspired by the existing 2D-to-3D lifting works [7, 25, 26] that a 3D pose could be accurately estimated by its corresponding 2D pose, $\beta$ and camera information, we assume that once $\{\mathbf{j},\mathbf{c},\beta \}$ are given, $\theta$ and $I$ are conditionally independent. As such, $I$ can be omitted as a conditioning variable. With Bayes' rule, the data distribution can be split as: + +$$ +p (\theta | I, \mathbf {j}, \mathbf {c}, \beta) = p (\theta | \mathbf {j}, \mathbf {c}, \beta) \propto p (\mathbf {j} | \mathbf {c}, \beta , \theta) \cdot p (\theta). \tag {7} +$$ + +The first decomposed term in Eq. (7), the likelihood $p(\mathbf{j}|\mathbf{c},\beta ,\theta)$ , is a projection consistency term that reflects the reconstruction accuracy. The second term, $p(\theta)$ , serves as a general pose prior in a probabilistic perspective [16, 21]. + +Model Distribution. Like previous works [22, 16, 21, 2], we estimate $\theta$ from an image $I$ , as the image contains sufficient information to infer $\mathbf{c}$ , $\beta$ and the keypoints $\mathbf{j}$ . The model distribution can be simplified as: + +$$ +p _ {\phi} (\theta | I, \mathbf {j}, \mathbf {c}, \beta) = p _ {\phi} (\theta | I). \tag {8} +$$ + +Based on Eqs. (7) and (8), the KL divergence between the model and data distributions can be expressed as: + +$$ +\begin{array}{l} K L \left(p _ {\phi} (\theta | I, \mathbf {j}, \mathbf {c}, \beta) \| p (\theta | I, \mathbf {j}, \mathbf {c}, \beta)\right) = \\ - \left(\underbrace {\underbrace {E _ {p _ {\phi} (\theta \mid I)} [ \log p (\mathbf {j} \mid \mathbf {c} , \beta , \theta) ]} _ {\text {r e c o n s t r u c t i o n}} + \underbrace {E _ {p _ {\phi} (\theta \mid I)} [ \log p (\theta) ]} _ {\text {p r i o r}} + \underbrace {H \left(p _ {\phi} (\theta \mid I)\right)} _ {\text {e n t r o p y}}\right), \tag {9} \\ \end{array} +$$ + +where $H(p_{\phi}(\theta |I)) = -E_{p_{\phi}(\theta |I)}[\log p_{\phi}(\theta |I)]$ is the entropy of $\theta$ given input image $I$ . See Suppl. B for the full derivation. Minimizing the KL divergence in Eq. (9) maximizes the reconstruction accuracy and the conditional entropy of the pose under pose prior $p(\theta)$ ; this can be used directly to supervise the neural network $\phi$ . + +Based on the above derivation, we propose a weakly-supervised multi-hypothesis framework as illustrated in Fig. 2. We consider only visible 2D keypoints as supervisory signals for the reconstruction. Like [21, 26], we assume that visible keypoints follow a Laplace distribution for sharpness. In line with the principle of maximum entropy (Sec. 3.4), the occluded keypoints each follow a uniform distribution of feasible locations. The intuition behind such an assumption is that, for occluded keypoints, we relax the supervision using prior knowledge $p(\theta)$ to generate feasible solutions for the image. This prevents an overconfident model that tries to fit all labels regardless of visibility and also compensates for the lack of one-to-many data-label pairs. As $\theta$ is derived from a parametric model, the prior can be applied simply as a uniform distribution [33] or adversarially [16] based on its representation. We choose to model the distribution $p_{\phi}(\theta |I)$ using a conditional NF model, i.e., $p_{\phi}(\theta |I) = \mathcal{F}^{-1}(\theta |I)$ , as it is more feasible to calculate the entropy term $H(p_{\phi}(\theta |I))$ via Monte Carlo (MC) sampling. Therefore, all three terms in Eq. (9) can be maximized by MC sampling and SGD [18]. + +An important part of our formulation involves the explicit maximization of entropy. The link between entropy and diverse hypotheses is highly intuitive, yet this has been overlooked in previous work. Even without one-to-many labels, the entropy term encourages the model $\phi$ to generate hypotheses that are diverse; the reconstruction and prior term ensure that the hypotheses respect the observed labels while remaining feasible. + +# 4.2. Implementation Details + +In Eq. (9), we represent image $I$ with image features extracted from a ResNet-50 [12] backbone. To estimate $\mathbf{c}$ and $\beta$ , we append a 512-hidden unit MLP to the backbone. For the normalizing flow model, we use the Real NVP[8]. + +First, to obtain $\theta$ for an image, according to LOTUS, we sample $\mathbf{z}_0$ from a Gaussian distribution and feed it together with image feature of $I$ to the invertible flow network $\mathcal{F}(\mathbf{z}|I)$ (the solid line in the yellow block in Fig. 2). + +Reconstruction. We use a constant scale $b$ for the Laplace and assume the joints do not exceed the large occlusion range (Suppl. B.2); the reconstruction loss simplifies to: + +$$ +\mathcal {L} _ {\text {r e c}} = \sum_ {k = 1} ^ {K} v _ {k} \| \mathbf {j} _ {k} - \hat {\mathbf {j}} _ {k} \| _ {1}, \tag {10} +$$ + +where $K$ is the number of joints and $\mathbf{j}_k$ represents $k$ -th joint; the loss is effective only on visible joints based on visibility indicator $v_k$ . + +Prior. To encourage feasible poses, we introduce a prior term $\mathcal{R}(\cdot)$ on $\theta$ . For MANO, $\theta$ is given as PCA coefficients. We empirically place a uniform distribution $\mathcal{R}(\theta) = \mathcal{U}(-2,2)$ on these coefficients, which covers most feasible solutions while avoiding invalid poses [33], i.e., + +$$ +\mathcal {L} _ {\theta} = \sum_ {i} \max (0, | \theta_ {i} | - 2) ^ {2}. \tag {11} +$$ + +For SMPL, $\theta$ represents axis-angle rotations and can be restricted by an adversarial prior [16], i.e., + +$$ +\mathcal {L} _ {\theta} = \operatorname {A d v} (\theta). \tag {12} +$$ + +Entropy. We use a negative log-likelihood loss: + +$$ +\mathcal {L} _ {H} = - \log p _ {\phi} (\theta | I), \tag {13} +$$ + +where $\theta$ is sampled from the normalizing flow. The reverse path of the NF, $\mathcal{F}^{-1}(\theta |I)$ , maps $\theta$ back to $\mathbf{z}_0$ in the latent space conditional on the image features to compute Eq. (4) [8, 17] (dashed lines in the yellow block in Fig. 2). + +The losses in Eqs. (10)-(13) each covers a term in Eq. (9). With the $\beta$ regularization in Eq. (2), all losses sum into the final training objective: + +$$ +\mathcal {L} = \lambda_ {\text {r e c}} \mathcal {L} _ {\text {r e c}} + \lambda_ {\theta} \mathcal {L} _ {\theta} + \lambda_ {H} \mathcal {L} _ {H} + \lambda_ {\beta} \mathcal {L} _ {\beta}, \tag {14} +$$ + +where the $\lambda$ s are the trade-off hyperparameters and $\mathcal{L}_{\beta} = ||\beta||_2^2$ . See Suppl. B for the full derivations and more training details. + +# 5. Experiments + +# 5.1. Datasets, Metrics, & Baselines + +Datasets. We synthesize a 2-joint toy setting in 2D to highlight components of our model. For the human body, we experiment on Human3.6M (H36M) [14] and its ambiguous version AH36M [2] with randomly truncated images of H36M to hide keypoints. Following [2, 21], we train with subjects S1 and S5-9 and test with S11, training with H36M and AH36M jointly, while evaluating separately. + +Inspired by AH36M, we construct Ambiguous RHD (ARHD) from the synthetic hand pose dataset RHD [43] by adding circular patches with a predefined radius to the fingers' DIP joints1. The visibility in the scene is affected depending on the finger and circle radius (see Fig. 5(c)). We also use HO3D [11], a real-world hand-object dataset that features severe occlusions. To evaluate the multi-hypothesis metrics, similar to previous work [38], we split a test subset from the training dataset. We estimate the visibility of a joint [9] by thresholding the difference between captured surface depth and the true keypoint position. More details of the datasets are provided in Suppl. D. + +Evaluation Metrics. Mean End-Point Error (EPE) is the average Euclidean distance between predicted and ground-truth joints, from which we consider the Best Hypothesis (BH) [25, 2] and our newly proposed All Hypothesis (AH). + +BH is a standard multi-hypothesis metric that selects the hypothesis with the lowest pose or mesh EPE. To evaluate the accuracy of all hypotheses, we propose AH, which is the mean EPE of all hypotheses on 2D visible joints to measure consistency to the image evidence. + +As we highlighted, multiple hypotheses should be diverse, but the diversity should only be on uncertain joints e.g. under occlusion. However, existing BH and diversity metrics [34, 26] do not capture this target because undesirable diversity on the visible joints may also contribute to the diversity metrics. Therefore, we propose to complement the evaluation of multi-hypothesis methods with Per-Joint Diversity (PJD) and a Relative Diversity (RD) ratio. + +PJD measures the standard deviation per joint and can be used to show the diversity of both visible and occluded joints in 2D and 3D spaces. To highlight the source of diversity, we propose a ratio: + +$$ +\mathbf {R D} = \frac {\mathrm {P J D} _ {2 \mathrm {d v i s}}}{\mathrm {P J D} _ {3 \mathrm {d o c c}}}, \tag {15} +$$ + +to account for the diversity of both the certain (i.e., 2D visible keypoints) and the uncertain parts (i.e., 3D occluded keypoints). A lower RD means more diversity on the occluded keypoints relative to visible keypoints. We follow [35, 37] and sample 200 hypotheses for evaluation. + +![](images/4712b23c6425c22645cf52713a09d21e9a69e9646278d1e39d8af81972351fdb.jpg) +(a) + +![](images/1bf4de5afb661faf898de40284ed9eb3cca2dc8f78e6b885cd7eb71c0d971aa4.jpg) +(b) + +![](images/35a9a440b2b7dd88061518a7fd845413e1787608d278b5ff1f8aeb30dad5bf14.jpg) +(c) + +![](images/f585497cb9d2991f6ed68443209a51ad5f62622bdb04f216cffa24e3efe6f2de.jpg) +Figure 3. (a) Toy problem setting featuring four modes. (b) Our probabilistic method in a weakly supervised setting recovers all the modes. (c) The deterministic method, even under strong supervision, predicts wrong modes as it easily overfits ubiquitous observation noise. +(a) +Figure 4. (a) Lowering the weight of the entropy term can impair multi-mode learning while (b) increasing the weights hurts the fitting accuracy, although it achieves diversity. (c) Choosing different feasibility priors will also make the final learned modes different. The second row shows the mode distribution in $\alpha$ space. + +![](images/11c277106590209922fa0cea4d5f25567d19907eb5175fba3851e76fc872a1e4.jpg) +(b) + +![](images/f40a56f853cca59e4aa5c1554420353bf8aa17c712a00fb106f6ae00ff340986.jpg) +(c) + +Baselines & SOTAs. We compare our method with two deterministic methods, Det (2D Vis) and Det (3D), which use visible 2D and all 3D keypoint positions as supervision, respectively. For more details, refer to a similar pipeline in [3]. Moreover, we compare our method with the state-of-the-art multi-hypothesis methods, including MDN [25], conditional VAE [35], Multi-bodies [2], ProHMR [21], CM-VAE [36] and WS3DPG [26]. + +Some of these approaches are designed with 3D pose supervision; we replace their corresponding supervised losses with the 2D version in Eq. (2). Unless specified, we also use visibility labels as weights while remaining as faithful as possible to the original method. See Suppl. F for method introductions and details. + +# 5.2. Toy Experiments & Ablation Studies + +Settings. We perform the toy experiment under a simple setting (depth ambiguity), as shown in Fig. 3(a). Consider a single chain with two keypoints plus a root keypoint. The bones are fixed to length 1 and the root is at the origin. The data $(\mathbf{y},\alpha)$ consists of the 1D projection $y_{k}$ of the keypoint on the y-axis and the angle $\alpha_{k}$ between the chain and the y-axis. From $\alpha_{k}$ , we can get 2D coordinates + +$\mathbf{j}_k = (\sin \alpha_k, \cos \alpha_k)$ relative to their parent. There are in total four Gaussian modes for the complete data, i.e., each joint can swing left and right. The model is trained to predict $\alpha$ based on $\mathbf{y}$ . For weak supervision, only 1D projections $\mathbf{y}$ are given. For strong supervision, all 2D coordinates $\mathbf{j}$ are provided. Our model uses an MLP and Real NVP as the backbone and optimizes an objective similar to Eq. (14). For the prior loss, we add an $L_2$ norm constraint on $\alpha$ . + +Deterministic vs. Multi-Hypothesis. The deterministic model trained under both weak and strong supervision can learn only one of the four modes. Moreover, under strong supervision, it is sensitive to similar input data and predicts wrong modes if the inputs are corrupted with small perturbations (Fig. 3(c)). In contrast, existing multi-hypothesis methods can recover all modes under strong supervision. + +Ours vs. Existing Multi-Hypothesis Methods. Existing methods require similar observations with multiple distinct ground-truth poses. In the weakly supervised setting, we compare with MDN and observe that it finds only one of the modes (Suppl. G.1) while our proposed method can successfully recover all the modes (Fig. 3(b)). + +Reconstruction vs. Entropy. The entropy term encourages the set of predictions to cover diverse solutions while maintaining a low reconstruction error. As the weight of the entropy term $\lambda_{H}$ decreases, the objective emphasizes reconstruction at the cost of entropy, leading to missed modes (Fig. 4(a)). The extreme is the degradation to a deterministic model. On the other hand, with the increase in $\lambda_{H}$ , the model pays less attention to reconstructing observed evidence, hence the modes become dispersed (Fig. 4(b)). + +Angle Prior. The prior term determines the distribution over the feasible solution space. When we lower the weight of the prior loss, the model may fit the evidence better but consider less feasible poses. On the other hand, prior knowledge defines the solution space, and the entropy term will encourage the predictions to cover all possible solutions based on the prior. For example, when we add a prior $\sin \alpha_{k} \geq 0$ for the top keypoints, some previous modes become infeasible and the model will only find two of the four original poses (Fig. 4(c)). + +# 5.3. Synthetic Ambiguous RHD + +Deterministic vs. Multi-Hypothesis. Table 1(a) shows that on ARHD, all the multi-hypothesis methods [25, 35, 26, 21, 37] outperform the deterministic 'Det (2D Vis)' on the BH metric. Some methods even outperform the 'Det (3D)' baseline with 3D supervision. + +
ARHDHO3D
BH (mm)↓ JointAH (pix)↓PJDRD↓BH (mm)↓ JointAH (pix)↓PJDRD↓
2D Vis3D Occ2D Vis3D Occ
Det (3D) [44]20.98----23.8825.18---
Det (2D Vis)25.1114.39---24.1025.4016.85--
Multi-bodies [2]20.5215.763.505.980.5922.0723.5619.571.920.62
MDN [25]21.3318.477.1412.690.5621.2822.6718.813.480.56
CVAE [35]20.9919.957.0210.660.6621.0422.6218.904.070.61
ProHMR [21]24.4413.370.130.220.5924.0525.4117.190.160.64
CM-VAE [36]21.9916.595.6710.400.5522.2023.5418.394.940.57
WS3DPG [26]24.3417.794.617.390.6223.6724.9918.343.060.65
Ours20.3513.423.8614.420.2720.5521.8316.953.300.28
+ +Table 1. Quantitative results on ARHD and HO3D V3. The best is marked in bold; the second best is underlined. Our method achieves competitive SOTA results; occluded keypoints are diverse while visible ones are relatively accurate, i.e., have a lower RD. + +![](images/eb100ef281def04bd3b48b79441da824319bae60226fbb1fe5aef52c9828e6e9.jpg) +(a) RD: 2D Vis PJD - 3D Occ PJD + +![](images/8565b98b46b71b67be7e83037f96cc19f3da2eeb44fd454d30d4450cfcf11670.jpg) +(b) PJD Curve Along Training +Figure 5. Illustration on ARHD. (a) Deviation from the diagonal (dashed line) towards the lower-right indicates a better trade-off between the 2D visible accuracy and 3D occluded diversity. (b) Comparison of PJD during learning for occluded (solid line) and visible (dashed line) keypoints. Our approach has a descending trend for visible keypoints and an ascending trend for the occluded ones. (c) Multi-hypothesis meshes. The red boxes highlight the concerned occluded keypoints. Our method predicts diverse and feasible poses under occlusion while MDN's predictions are inconsistent with image evidence on visible keypoints. + +![](images/c37cdbc126cdd9baf11e5010788b63840dc6b751c50a7652c3f3ff8157067a5a.jpg) +(c) Qualitative Results + +Comparisons with SOTA. Methods like MDN [25] and CVAE [35] all have low BH (Tab. 1(a)). However, their diversity (PJD) for visible and occluded keypoints is high, i.e., the entire hand is diverse. Together with a large AH, this suggests that their hypotheses as a whole do not fit the image evidence well. ProHMR [21] degenerates to an almost deterministic method, and has the lowest PJD for visible and occluded keypoints. We speculate that it is because of its reliance on the strong supervision for $\theta$ labels. More comparisons can be found in Sec. 5.5. + +In contrast, our framework obtains lower BH and AH and higher occluded diversity (higher $\mathrm{PJD}_{\mathrm{occ}}$ and thus significantly lower RD). Fig. 5(a) shows that we strike a good balance between reconstruction and diversity; qualitatively, Fig. 5(c) shows that our recovered meshes are diverse and consistent with the observation. + +Connection to Existing Works & Ablation Studies. ProHMR [21], CM-VAE [36], and WS3DPG [26] are closely related to our method. Among them, ProHMR + +is a variant without entropy optimization; CM-VAE [36] applies a single Gaussian distribution instead of our NF; WS3DPG [26] uses a GAN whose entropy is intractable. Tab. 1(a) shows that our entropy term increases the PJD significantly, especially for occluded joints in 3D (ProHMR's 0.22 vs. our 14.42). Moreover, we outperform CM-VAE and WS3DPG on all metrics on ARHD, showing the powerful ability of NFs to model complex distributions and estimate entropy. Additional ablations on visibility in Suppl. G.2 shows that adding additional supervision on occluded joints hurts diversity. + +PJD During Training. Fig. 5(b) shows the test PJD scores throughout training. The PJD of MDN [25] for both visible and occluded keypoints decreases as training progresses. Meanwhile, CVAE [35] has the opposite trend, with increasing PJD scores for both types of keypoints. In contrast, our approach has a descending trend on the PJD of visible keypoints and an ascending trend on the occluded ones (Tab. 1(a)). + +![](images/544d4b0e682ae6d49f9d06d387ef5e5e81da719102965c4f285cdac949f74e66.jpg) +Figure 6. Visualization of our multiple hypotheses on HO3D. + +![](images/255b6c6bc03ce4fd58a307d5c86609122933c87da8459cd2b6399b737d472f99.jpg) +Figure 7. Visualization of hypotheses with the smallest and largest HOI Chamfer distance in two views. Differences are highlighted with red boxes. Hypothesis selection leads to more feasible grasps. + +![](images/9395993369b957f7e871b35ddba189b68803fe229b26a19f2ca6eb1aa7a77daa.jpg) +Figure 8. Qualitative results on AH36M. The legs of our hypotheses are much more diverse, while all trunks are consistent with the image. The green mesh is the ground-truth. + +# 5.4. Real-World Data: HO3D + +When faced with real-world ambiguous settings, such as objects occluding hands, our method is state-of-the-art compared to other multi-hypothesis methods. The results in Tab. 1(b) and Fig. 6 are consistent with the trends on the synthetic ARHD – our method has the lowest BH and RD. + +Hypothesis Selection. With additional input information, the multiple hypotheses can be filtered for an improved set of solutions. We show an example of hypothesis selection in which we select feasible grasps based on the object interaction. We simply use a post-processing strategy to select samples. Specifically, we use a hand-object interaction (HOI) feasibility metric, e.g., the widely used Chamfer distance [4]. Based on the value of the Chamfer distance, we can select hypotheses. We found it useful for picking + +more plausible poses from hypotheses using task-related constraints. We visualize hypotheses with the lowest and highest HOI Chamfer distance in Fig. 7. Our hypotheses are all consistent with the image cues in the front camera view. From a different view, by incorporating the HOI constraint for hypotheses, we can select more feasible grasp poses. + +Meaningful Diversity. The purpose of our method is to encourage meaningful diversity; hence we treat visible and occluded joints differently. The quality of diversity can be further improved by incorporating more information about the observed ambiguity. One example is to add mask information about the occlusions; it can be incorporated into our framework as a post-hoc hypothesis selection during inference or as a reconstruction loss in Eq. (9) during training. In both ways, the error rate for out-of-occlusion can therefore be reduced without much loss in diversity (Suppl. G.2). + +# 5.5. State-of-The-Art on H36M & AH36M + +
SupervisionMHH36MAH36M
2D VisHMR67.485.2
ProHMR✓64.382.6
Ours✓51.366.4
3DHMR56.8-
SPIN41.1-
MDN✓42.769.5
CVAE✓46.275.1
Multi-bodies✓42.264.2
ProHMR✓36.860.1
Ours✓36.850.6
+ +Table 2. PA-MPJPE (mm) of BH results on H36M and its ambiguous version AH36M under the supervision of visible 2D keypoints (2D Vis) and 3D keypoints (3D) with $n = 25$ . + +
SupervisionAH (pix)↓PJDRD↓
2D Vis3D Occ
2D VisProHMR10.920.060.260.23
Ours9.754.5664.050.07
3DProHMR13.383.9824.270.16
Ours10.734.2347.950.09
+ +Table 3. Diversity metrics on AH36M under the supervision of visible 2D keypoints (2D Vis) and 3D keypoints (3D). + +Our framework is also effective for human pose estimation. We follow [2, 21] and evaluate the accuracy and diversity of hypotheses on the benchmark H36M and its ambiguous version AH36M. Besides using 2D visible keypoints as supervision, we also test a variant using 3D keypoints. For supervision with 3D keypoints, we follow ProHMR [21] and supervise the predicted 3D poses from SMPL directly. + +Tab. 2 shows that we achieve the best BH on both datasets with different supervision settings. Our method has an impressive $9.5\mathrm{mm}$ improvement on AH36M with 3D + +keypoints as labels; furthermore, our performance with 2D visible keypoints as weak labels is comparable to using 3D keypoints as labels. Comparing diversity metrics in Tab. 3 and Fig. 8, we outperform ProHMR with respect to AH and RD. Our method with the entropy term predicts highly diverse results in the weakly-supervised setting. + +
H36MAH36M
Multi-ViewFittingFitting
ProHMR34.534.861.4
Ours34.234.453.5
+ +Table 4. PA-MPJPE (mm) of downstream tasks multi-view refinement and fitting humans with 2D ground-truth. For these tasks, a trained model distribution outputs only one hypothesis by observing more evidence. + +Downstream Tasks. Our method, by estimating an accurate yet diverse set of hypotheses, excels at providing inputs for downstream tasks. We verify the hypotheses through multi-view refinement and fitting humans with 2D ground-truth on H36M and AH36M. We follow ProHMR to find the solution that best matches the evidence among many possible hypotheses by optimization, i.e., + +$$ +\max _ {\theta} \log p _ {\phi} (\theta | I) + c (\theta | \mathbf {e}), \tag {16} +$$ + +where $c(\theta | \mathbf{e})$ is consistency with additional information, e.g., multi-view and 2D projection consistency. Lower PA-MPJPE in Tab. 4 verifies our effectiveness, which may imply ours obtains a better representation with a more accurate distribution than ProHMR. + +# 6. Discussion & Conclusion + +Our proposed multi-hypothesis framework is flexible, efficient, and label-friendly. We emphasize that diversity in the hypotheses should not be arbitrary; instead, it should come from ambiguity present in the image itself. To that end, we also propose a more comprehensive evaluation scheme based on visibility. In our work, we have only considered ambiguity from object occlusions and image truncations, but additional factors such as image quality and light are interesting directions to investigate for future work. + +We note that by virtue of evaluating on the provided annotations of the current datasets, the diversity concept remains vague and limited to the dataset. For instance, in-distribution testing aims to learn the pose diversity captured in that dataset. It may not require learning more diverse outdoor poses to achieve a good BH on indoor datasets and thus not conducive to generalization to other scenarios. It is suggested to focus more on the improvement and evaluation of the diversity in the generalization scenario. + +Acknowledgments. This research/project is supported by the Ministry of Education, Singapore, under its MOE Academic Research Fund Tier 2 (STEM RIE2025 MOET2EP20220-0015). We would also like to thank the ACs, reviewers, Dr. Chen Li, and Junpeng Hu for their valuable suggestions. + +# References + +[1] Mahmoud Assran, Mathilde Caron, Ishan Misra, Piotr Bojanowski, Florian Bordes, Pascal Vincent, Armand Joulin, Mike Rabbat, and Nicolas Ballas. Masked siamese networks for label-efficient learning. In ECCV, 2022. 3 +[2] Benjamin Biggs, David Novotny, Sebastien Ehrhardt, Hanbyul Joo, Ben Graham, and Andrea Vedaldi. 3D Multibodies: Fitting sets of plausible 3D human models to ambiguous image data. In NeurIPS, 2020. 1, 2, 4, 5, 6, 7, 8 +[3] Adnane Boukhayma, Rodrigo de Bem, and Philip HS Torr. 3D hand shape and pose from images in the wild. In CVPR, 2019. 1, 2, 3, 6 +[4] Zhe Cao, Ilija Radosavovic, Angjoo Kanazawa, and Jitendra Malik. Reconstructing hand-object interactions in the wild. In ICCV, 2021. 8 +[5] Ping Chen, Yujin Chen, Dong Yang, Fangyin Wu, Qin Li, Qingpei Xia, and Yong Tan. I2UV-HandNet: Image-to-UV prediction network for accurate and high-fidelity 3D hand mesh modeling. In ICCV, 2021. 2 +[6] Zerui Chen, Yana Hasson, Cordelia Schmid, and Ivan Laptev. AlignSDF: Pose-aligned signed distance fields for hand-object reconstruction. In ECCV, 2022. 2 +[7] Hongsuk Choi, Gyeongsik Moon, and Kyoung Mu Lee. Pose2Mesh: Graph convolutional network for 3D human pose and mesh recovery from a 2D human pose. In ECCV, 2020. 1, 4 +[8] Laurent Dinh, Jascha Sohl-Dickstein, and Samy Bengio. Density estimation using real NVP. In ICLR, 2017. 3, 5 +[9] Kerui Gu, Linlin Yang, and Angela Yao. Removing the bias of integral pose regression. In ICCV, 2021. 5 +[10] Silviu Guiasu and Abe Shenitzer. The principle of maximum entropy. Math. Intell., 7(1):42-48, 1985. 2, 3 +[11] Shreyas Hampali, Mahdi Rad, Markus Oberweger, and Vincent Lepetit. HOnnotate: A method for 3D annotation of hand and object poses. In CVPR, 2020. 5 +[12] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, 2016. 5 +[13] R Devon Hjelm, Alex Fedorov, Samuel Lavoie-Marchildon, Karan Grewal, Phil Bachman, Adam Trischler, and Yoshua Bengio. Learning deep representations by mutual information estimation and maximization. In ICLR, 2019. 3 +[14] Catalin Ionescu, Dragos Papava, Vlad Olaru, and Cristian Sminchisescu. Human3.6M: Large scale datasets and predictive methods for 3D human sensing in natural environments. TPAMI, 36(7):1325-1339, 2013. 5 +[15] Umar Iqbal, Pavlo Molchanov, Thomas Breuel Juergen Gall, and Jan Kautz. Hand pose estimation via latent 2.5D heatmap regression. In ECCV, 2018. 1 + +[16] Angjoo Kanazawa, Michael J Black, David W Jacobs, and Jitendra Malik. End-to-end recovery of human shape and pose. In CVPR, 2018. 2, 3, 4, 5 +[17] Durk P Kingma and Prafulla Dhariwal. Glow: Generative flow with invertible 1x1 convolutions. In NeurIPS, 2018. 5 +[18] Diederik P. Kingma and Max Welling. Auto-encoding variational Bayes. In ICLR, 2014. 4 +[19] Muhammed Kocabas, Nikos Athanasiou, and Michael J Black. VIBE: Video inference for human body pose and shape estimation. In CVPR, 2020. 2 +[20] Nikos Kolotouros, Georgios Pavlakos, Michael J Black, and Kostas Daniilidis. Learning to reconstruct 3D human pose and shape via model-fitting in the loop. In ICCV, 2019. 2 +[21] Nikos Kolotouros, Georgios Pavlakos, Dinesh Jayaraman, and Kostas Daniilidis. Probabilistic modeling for human mesh recovery. In ICCV, 2021. 1, 2, 4, 5, 6, 7, 8 +[22] Dominik Kulon, Riza Alp Guler, Iasonas Kokkinos, Michael M Bronstein, and Stefanos Zafeiriou. Weakly-supervised mesh-convolutional hand reconstruction in the wild. In CVPR, 2020. 2, 3, 4 +[23] Rithesh Kumar, Sherjil Ozair, Anirudh Goyal, Aaron Courville, and Yoshua Bengio. Maximum entropy generators for energy-based models. In arXiv:1901.08508, 2019. 3 +[24] Jogendra Nath Kundu, Siddharth Seth, Pradyumna YM, Varun Jampani, Anirban Chakraborty, and R Venkatesh Babu. Uncertainty-aware adaptation for self-supervised 3d human pose estimation. In CVPR, 2022. 3 +[25] Chen Li and Gim Hee Lee. Generating multiple hypotheses for 3D human pose estimation with mixture density network. In CVPR, 2019. 1, 2, 3, 4, 5, 6, 7 +[26] Chen Li and Gim Hee Lee. Weakly supervised generative network for multiple 3D human pose hypotheses. In BMVC, 2020. 1, 3, 4, 5, 6, 7 +[27] Wenhao Li, Hong Liu, Hao Tang, Pichao Wang, and Luc Van Gool. MHFormer: Multi-hypothesis transformer for 3D human pose estimation. In CVPR, 2022. 1 +[28] Kevin Lin, Lijuan Wang, and Zicheng Liu. End-to-end human pose and mesh reconstruction with transformers. In CVPR, 2021. 1, 2 +[29] Xin Liu, Zhongdao Wang, Ya-Li Li, and Shengjin Wang. Self-supervised learning via maximum entropy coding. 2022. 3 +[30] Matthew Loper, Naureen Mahmood, Javier Romero, Gerard Pons-Moll, and Michael J Black. SMPL: A skinned multiperson linear model. TOG, 34(6):1-16, 2015. 2, 3 +[31] Gyeongsik Moon and Kyoung Mu Lee. I2L-MeshNet: Image-to-lixel prediction network for accurate 3D human pose and mesh estimation from a single RGB image. In ECCV, 2020. 1, 2 +[32] George Papamakarios, Eric T Nalisnick, Danilo Jimenez Rezende, Shakir Mohamed, and Balaji Lakshminarayanan. Normalizing flows for probabilistic modeling and inference. JMLR, 22(57):1-64, 2021. 3 +[33] Javier Romero, Dimitrios Tzionas, and Michael J. Black. Embodied Hands: Modeling and capturing hands and bodies together. TOG, 36(6):1-17, 2017. 2, 3, 4, 5 + +[34] Akash Sengupta, Ignas Budvytis, and Roberto Cipolla. Hierarchical kinematic probability distributions for 3D human shape and pose estimation from images in the wild. In ICCV, 2021. 5 +[35] Saurabh Sharma, Pavan Teja Varigonda, Prashast Bindal, Abhishek Sharma, and Arjun Jain. Monocular 3D human pose estimation by generation and ordinal ranking. In ICCV, 2019. 1, 2, 5, 6, 7 +[36] Adrian Spurr, Jie Song, Seonwook Park, and Otmar Hilliges. Cross-modal deep variational hand pose estimation. In CVPR, 2018. 6, 7 +[37] Tom Wehrbein, Marco Rudolph, Bodo Rosenhahn, and Bastian Wandt. Probabilistic monocular 3D human pose estimation with normalizing flows. In ICCV, 2021. 1, 2, 5, 6 +[38] Lixin Yang, Xinyu Zhan, Kailin Li, Wenqiang Xu, Jiefeng Li, and Cewu Lu. CPF: Learning a contact potential field to model the hand-object interaction. In ICCV, 2021. 5 +[39] Qi Ye and Tae-Kyun Kim. Occlusion-aware hand pose estimation using hierarchical mixture density network. In ECCV, 2018. 1, 2 +[40] Ziwei Yu, Linlin Yang, You Xie, Ping Chen, and Angela Yao. UV-based 3D hand-object reconstruction with grasp optimization. In BMVC, 2022. 2 +[41] Andrei Zanfir, Eduard Gabriel Bazavan, Hongyi Xu, William T Freeman, Rahul Sukthankar, and Cristian Sminchisescu. Weakly supervised 3D human pose and shape reconstruction with normalizing flows. In ECCV, 2020. 2 +[42] Wang Zeng, Wanli Ouyang, Ping Luo, Wentao Liu, and Xiaogang Wang. 3D human mesh regression with dense correspondence. In CVPR, 2020. 2 +[43] Christian Zimmermann and Thomas Brox. Learning to estimate 3D hand pose from single RGB images. In ICCV, 2017. 5 +[44] Christian Zimmermann, Duygu Ceylan, Jimei Yang, Bryan Russell, Max Argus, and Thomas Brox. FreiHAND: A dataset for markerless capture of hand pose and shape from single RGB images. In ICCV, 2019. 7 \ No newline at end of file diff --git a/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/images.zip b/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..1e80e61f97c2c285e6dda5b2d3e2bd83a9a2da34 --- /dev/null +++ b/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:59ebc6f7f10f7fd7d8dcbce2ab2b01297b95fcdce80e5b472702c3ba664ea7a8 +size 484295 diff --git a/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/layout.json b/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..263c7ca5796d79af0a9357b7e1e0f6f94749cf62 --- /dev/null +++ b/2023/MHEntropy_ Entropy Meets Multiple Hypotheses for Pose and Shape Recovery/layout.json @@ -0,0 +1,10499 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 52, + 103, + 541, + 122 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 103, + 541, + 122 + ], + "spans": [ + { + "bbox": [ + 52, + 103, + 541, + 122 + ], + "type": "text", + "content": "MHEntropy: Entropy Meets Multiple Hypotheses for Pose and Shape Recovery" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 178, + 143, + 416, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 178, + 143, + 416, + 185 + ], + "spans": [ + { + "bbox": [ + 178, + 143, + 416, + 185 + ], + "type": "text", + "content": "Rongyu Chen* Linlin Yang* Angela Yao National University of Singapore {rchen, yangll, ayao}@comp.nus.edu.sg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "spans": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 239, + 290, + 431 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 239, + 290, + 431 + ], + "spans": [ + { + "bbox": [ + 46, + 239, + 290, + 431 + ], + "type": "text", + "content": "For monocular RGB-based 3D pose and shape estimation, multiple solutions are often feasible due to factors like occlusions and truncations. This work presents a multi-hypothesis probabilistic framework by optimizing the Kullback-Leibler divergence (KLD) between the data and model distribution. Our formulation reveals a connection between the pose entropy and diversity in the multiple hypotheses that has been neglected by previous works. For a comprehensive evaluation, besides the best hypothesis (BH) metric, we factor in visibility for evaluating diversity. Additionally, our framework is label-friendly - it can be learned from only partial 2D keypoints, such as visible keypoints. Experiments on both ambiguous and real-world benchmarks demonstrate that our method outperforms other state-of-the-art multi-hypothesis methods. The project page is at https://gloryyrolg.github.io/MHEntropy." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 455, + 128, + 467 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 455, + 128, + 467 + ], + "spans": [ + { + "bbox": [ + 47, + 455, + 128, + 467 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 476, + 287, + 608 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 476, + 287, + 608 + ], + "spans": [ + { + "bbox": [ + 46, + 476, + 287, + 608 + ], + "type": "text", + "content": "Pose and shape estimation is a core component of augmented and virtual reality applications. The majority of monocular 3D pose and shape estimation approaches [28, 31, 7, 3, 15] are designed to predict only a single solution, yet 3D recovery from a monocular input is an inverse problem. Multiple solutions are feasible, especially under settings with occlusions, truncations, low image quality, or other ambiguities. It is therefore meaningful and desirable to make multi-hypothesis predictions. Multiple hypotheses are also useful in downstream tasks such as 2D keypoint fitting [21] and multi-view fusion [21, 25]." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 609, + 288, + 693 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 609, + 288, + 693 + ], + "spans": [ + { + "bbox": [ + 46, + 609, + 288, + 693 + ], + "type": "text", + "content": "Previous multi-hypothesis works use various 2D [2, 21, 37], 3D [39, 25, 2, 21, 37, 35], and mesh [2] reconstruction losses to facilitate kinematically feasible poses and shapes, while encouraging diversity in the solution set. Yet the learning and evaluation for multi-hypothesis works are underdeveloped. Learning-wise, many existing works are not label-friendly and often require one-to-many labeled data to" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 334, + 217, + 411, + 294 + ], + "blocks": [ + { + "bbox": [ + 334, + 217, + 411, + 294 + ], + "lines": [ + { + "bbox": [ + 334, + 217, + 411, + 294 + ], + "spans": [ + { + "bbox": [ + 334, + 217, + 411, + 294 + ], + "type": "image", + "image_path": "258c6c837eb60aac6fbe5c41b5378260feca4df7befe2ec9f66624b76f27cc1b.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 337, + 301, + 400, + 312 + ], + "lines": [ + { + "bbox": [ + 337, + 301, + 400, + 312 + ], + "spans": [ + { + "bbox": [ + 337, + 301, + 400, + 312 + ], + "type": "text", + "content": "(a) Occluded Input" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 424, + 225, + 510, + 289 + ], + "blocks": [ + { + "bbox": [ + 424, + 225, + 510, + 289 + ], + "lines": [ + { + "bbox": [ + 424, + 225, + 510, + 289 + ], + "spans": [ + { + "bbox": [ + 424, + 225, + 510, + 289 + ], + "type": "image", + "image_path": "333fac67ee15126e3d89ff441679c070e2c844b5f93798fd24154b4e88bc8f48.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 415, + 301, + 507, + 311 + ], + "lines": [ + { + "bbox": [ + 415, + 301, + 507, + 311 + ], + "spans": [ + { + "bbox": [ + 415, + 301, + 507, + 311 + ], + "type": "text", + "content": "(b) Visible versus Occluded" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 341, + 317, + 395, + 368 + ], + "blocks": [ + { + "bbox": [ + 341, + 317, + 395, + 368 + ], + "lines": [ + { + "bbox": [ + 341, + 317, + 395, + 368 + ], + "spans": [ + { + "bbox": [ + 341, + 317, + 395, + 368 + ], + "type": "image", + "image_path": "f6f069c6c20abddaac054f456da55cb3c4a9d3a879f2bb39c37ce72917605888.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 376, + 374, + 457, + 384 + ], + "lines": [ + { + "bbox": [ + 376, + 374, + 457, + 384 + ], + "spans": [ + { + "bbox": [ + 376, + 374, + 457, + 384 + ], + "type": "text", + "content": "(c) Multiple Hypotheses" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 400, + 316, + 446, + 370 + ], + "blocks": [ + { + "bbox": [ + 400, + 316, + 446, + 370 + ], + "lines": [ + { + "bbox": [ + 400, + 316, + 446, + 370 + ], + "spans": [ + { + "bbox": [ + 400, + 316, + 446, + 370 + ], + "type": "image", + "image_path": "3721891385bd9b692eae5fb57fc66a60231ff5dd1da61fa597d46d659d2ce8cf.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 452, + 316, + 514, + 371 + ], + "blocks": [ + { + "bbox": [ + 452, + 316, + 514, + 371 + ], + "lines": [ + { + "bbox": [ + 452, + 316, + 514, + 371 + ], + "spans": [ + { + "bbox": [ + 452, + 316, + 514, + 371 + ], + "type": "image", + "image_path": "c554c1e2bff2722f9ba37fef492874895dca1bcbb34e5bd6c7bb07446292ef06.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 306, + 388, + 545, + 411 + ], + "lines": [ + { + "bbox": [ + 306, + 388, + 545, + 411 + ], + "spans": [ + { + "bbox": [ + 306, + 388, + 545, + 411 + ], + "type": "text", + "content": "Figure 1. Our method estimates diverse and feasible hypotheses for occluded joints while preserving accuracy for visible joints." + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_caption" + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 435, + 546, + 543 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 435, + 546, + 543 + ], + "spans": [ + { + "bbox": [ + 304, + 435, + 546, + 543 + ], + "type": "text", + "content": "achieve diversity [21, 2, 35, 25], i.e., similar ambiguous observations with multiple distinct ground-truth poses. Such labels are challenging to obtain, especially under occlusion or out-of-view scenarios for which multi-hypothesis predictions are the most meaningful. While empirical efforts have been made to avoid mode collapse while encouraging diversity [26, 27], these methods often do not fully explore the solution space. It is, therefore, non-trivial to achieve feasible and as diverse as possible solutions." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 546, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 546, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 546, + 547, + 714 + ], + "type": "text", + "content": "Evaluation-wise, multi-hypothesis works use the best hypothesis (BH) as the metric of choice [25, 2, 21, 37, 26]. BH measures the closest distance between a hypothesis set and the ground truth. It emphasizes the accuracy of the closest hypothesis while ignoring the set holistically. Few works explicitly and quantitatively evaluate the diversity of the predicted hypotheses. When they do so, diversity is evaluated independently from the input [26]. Yet joints under occlusion or a lack of evidence feature more uncertainty, and as such should correspond to more diversity, while joints should be less diverse on unambiguous parts. Current multi-hypothesis evaluation schemes do not make such distinctions. Unwanted diversity on unambiguous joints also contributes to the calculation of overall diversity." + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 703, + 126, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 703, + 126, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 703, + 126, + 712 + ], + "type": "text", + "content": "*Equal contribution." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "14840" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 288 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 288 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 288 + ], + "type": "text", + "content": "This paper addresses these shortcomings and presents a new multi-hypothesis framework for estimating 3D poses and shapes. At the heart of our method is a simple yet essential underlying criterion - hypotheses should be diverse, but meaningfully so, and correlate with an observation's ambiguity (see Fig. 1 (b)). To that end, we take a probabilistically principled approach and minimize the Kullback-Leibler (KL) divergence between the model distribution and the underlying data distribution. Our objective results in three terms: a reconstruction accuracy, a pose prior, and most interestingly, a model entropy term. This additional entropy term echoes the principle of maximum entropy [10], where the probability distribution is designed to align with observations but otherwise be as unbiased as possible. For pose estimation, this means that visible and unambiguous keypoints should remain fixed across the hypotheses, while occluded and ambiguous keypoints should be feasible yet diverse (see Fig. 1 (b) and (c))." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 288, + 289, + 395 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 288, + 289, + 395 + ], + "spans": [ + { + "bbox": [ + 47, + 288, + 289, + 395 + ], + "type": "text", + "content": "Unlike existing works [35, 25, 21], our formulation for diversity does not require one-to-many training data. Instead, our model is trained by explicitly encouraging it to explore the feasible solution space via entropy maximization while remaining consistent with the evidence. For the implementation of our framework, we learn a conditional distribution of parameters with a normalizing flow model. The parameters modelled come from parametric 3D models like MANO [33] and SMPL [30]." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 396, + 289, + 479 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 396, + 289, + 479 + ], + "spans": [ + { + "bbox": [ + 47, + 396, + 289, + 479 + ], + "type": "text", + "content": "To be label-friendly, we advocate using weak labels; specifically, we recommend 2D keypoints from only visible joints. Using 2D keypoint labels is well established in the literature [3, 22]. However, considering only visible 2D keypoints is not well-studied, even though it is highly intuitive from an annotation point of view and a natural fit for multiple hypotheses." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 479, + 289, + 598 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 479, + 289, + 598 + ], + "spans": [ + { + "bbox": [ + 47, + 479, + 289, + 598 + ], + "type": "text", + "content": "For a comprehensive evaluation beyond the best hypothesis we introduce a Per-Joint Diversity (PJD) to measure the diversity of visible and occluded keypoints. Based on PJD, we further propose a Relative Diversity (RD) ratio to measure the reasonable diversity of the hypotheses. A low ratio indicates that observed keypoints are deterministic while occluded keypoints are diverse. In experiments, our method finds highly accurate BH and achieves the best RD ratio compared to other multi-hypothesis approaches. To summarize our contributions," + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 59, + 609, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 59, + 609, + 287, + 669 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 609, + 287, + 669 + ], + "spans": [ + { + "bbox": [ + 59, + 609, + 287, + 669 + ], + "type": "text", + "content": "- We formulate multi-hypothesis estimation as a minimization of the KL divergence between the model distribution and the data distribution. This formulation is probabilistically principled and naturally yields an entropy term that encourages diversity in the solution set." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 59, + 677, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 677, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 59, + 677, + 287, + 713 + ], + "type": "text", + "content": "- From our KL formulation, we propose a framework to estimate multiple hypotheses of 3D pose and shape that favours feasible and diverse solutions by design." + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 317, + 72, + 547, + 181 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 317, + 72, + 545, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 72, + 545, + 120 + ], + "spans": [ + { + "bbox": [ + 317, + 72, + 545, + 120 + ], + "type": "text", + "content": "- We emphasize visibility in multi-hypothesis frameworks by exploring visible 2D keypoints, i.e. partial weak labels for estimating 3D pose and shape and factoring in visibility for evaluating diversity." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 133, + 547, + 181 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 133, + 547, + 181 + ], + "spans": [ + { + "bbox": [ + 317, + 133, + 547, + 181 + ], + "type": "text", + "content": "- Experiments on toy, ambiguous, and real-world data demonstrate that our method achieves excellent diversity and the best BH compared to other state-of-the-art multi-hypothesis methods." + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 197, + 392, + 209 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 197, + 392, + 209 + ], + "spans": [ + { + "bbox": [ + 306, + 197, + 392, + 209 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 217, + 523, + 231 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 217, + 523, + 231 + ], + "spans": [ + { + "bbox": [ + 306, + 217, + 523, + 231 + ], + "type": "text", + "content": "2.1. 3D Human/Hand Pose & Shape Recovery" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 237, + 547, + 393 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 237, + 547, + 393 + ], + "spans": [ + { + "bbox": [ + 304, + 237, + 547, + 393 + ], + "type": "text", + "content": "Existing works estimate 3D pose and shape either directly [3, 16, 20, 19], or indirectly [5, 28, 31] via a parametric model like SMPL and MANO. Parametric models serve as priors to encourage feasible solutions [3, 16] and reduce the reliance on labels [22, 41]. The parameters of parametric models are typically learned under the supervision of 3D meshes and poses [3, 16, 20, 19]. Without parametric models, works like [42, 5, 28, 31, 22] focus on the representations of 3D surfaces and the design of architectures. They convert the surfaces into different 3D representations like mesh vertices [31, 28], UV mapping [42, 5, 40], and implicit representations [6], and then fit the surfaces based on architectures like GCNs [22] and Transformers [28]." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 403, + 454, + 417 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 403, + 454, + 417 + ], + "spans": [ + { + "bbox": [ + 306, + 403, + 454, + 417 + ], + "type": "text", + "content": "2.2. Multi-Hypothesis Methods" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 423, + 547, + 532 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 423, + 547, + 532 + ], + "spans": [ + { + "bbox": [ + 304, + 423, + 547, + 532 + ], + "type": "text", + "content": "These methods predict diverse and feasible predictions from ambiguous input evidence, often via deep generative models. The work in [35] proposes a conditional VAE to model the distribution of a 3D pose sample set that is consistent with the 2D pose, which helps to tackle the inherent ambiguity in 2D-to-3D lifting. MDN-based works [39, 25] introduce mixture density models to estimate multiple hypotheses by minimizing the negative log-likelihood of a multi-modal mixture of Gaussians." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 533, + 547, + 652 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 547, + 652 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 547, + 652 + ], + "type": "text", + "content": "More recent works [37, 2, 21] apply normalizing flow (NF) models. The work in [2] directly employs NFs as a prior on the distribution of plausible poses at test time. Differently, other works, like [37, 21], propose using a conditional NF. Specifically, [21] uses the conditional NF to model the distribution of SMPL pose parameters conditioned on the 2D image, while [37] adopts predicted 2D keypoints as a condition for the NF and specifically considers 2D poses in the latent space to model the distribution from 3D poses to 2D poses and its reverse." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": "Despite their use of probabilistic modeling, few existing works use explicit distributional optimization objectives. Our proposed method is derived directly from KL divergence, which also brings an entropy term and explicitly encourages the estimation of multiple hypotheses." + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "14841" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 71, + 133, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 71, + 133, + 83 + ], + "spans": [ + { + "bbox": [ + 47, + 71, + 133, + 83 + ], + "type": "text", + "content": "3. Preliminaries" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 110, + 220, + 122 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 110, + 220, + 122 + ], + "spans": [ + { + "bbox": [ + 47, + 110, + 220, + 122 + ], + "type": "text", + "content": "3.1. Overview of Parametric Models" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "spans": [ + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "text", + "content": "MANO [33] and SMPL [30] are commonly-used parametric 3D models for human hands and bodies with pose parameters " + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "inline_equation", + "content": "\\theta \\in \\mathbb{R}^{N_{\\theta}}" + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "text", + "content": " and shape parameters " + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "inline_equation", + "content": "\\beta \\in \\mathbb{R}^{N_{\\beta}}" + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "text", + "content": ". Usually, " + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "text", + "content": " are expressed as axis-angle rotations and PCA coefficients learned from pose data and registered shapes, respectively, though " + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "text", + "content": " can also be expressed as PCA coefficients for MANO. Together, " + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "text", + "content": " fully determine the surface mesh " + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "inline_equation", + "content": "\\mathcal{M}(\\theta ,\\beta)\\in \\mathbb{R}^{N_m\\times 3}" + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "text", + "content": " and joint coordinates " + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "inline_equation", + "content": "\\mathcal{J}(\\theta ,\\beta)\\in \\mathbb{R}^{N_j\\times 3}" + }, + { + "bbox": [ + 46, + 128, + 287, + 236 + ], + "type": "text", + "content": " in the 3D space." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "spans": [ + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "text", + "content": "Given camera parameters " + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "inline_equation", + "content": "\\mathbf{c} = \\{R, \\mathbf{t}, s\\}" + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "inline_equation", + "content": "R \\in \\mathbb{R}^{3 \\times 3}" + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "text", + "content": " is a global rotation matrix, " + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "inline_equation", + "content": "\\mathbf{t} \\in \\mathbb{R}^2" + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "text", + "content": " is the translation, and " + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "text", + "content": " is a scaling factor, the 3D pose " + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "inline_equation", + "content": "\\mathcal{J}(\\theta, \\beta)" + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "text", + "content": " can be projected into 2D joints " + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "inline_equation", + "content": "\\mathbf{j}" + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "text", + "content": " with an orthographic projection " + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "inline_equation", + "content": "\\Pi" + }, + { + "bbox": [ + 47, + 236, + 288, + 285 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 108, + 292, + 287, + 305 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 108, + 292, + 287, + 305 + ], + "spans": [ + { + "bbox": [ + 108, + 292, + 287, + 305 + ], + "type": "interline_equation", + "content": "\\mathbf {j} = s \\cdot \\Pi (R \\cdot \\mathcal {J} (\\theta , \\beta)) + \\mathbf {t}. \\tag {1}", + "image_path": "7b97f52c84ec31cb5b7a55836f33f18b5aaedaa217398c20f1212194701853bd.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 312, + 187, + 324 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 312, + 187, + 324 + ], + "spans": [ + { + "bbox": [ + 47, + 312, + 187, + 324 + ], + "type": "text", + "content": "3.2. 2D Keypoint Supervision" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 330, + 287, + 416 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 330, + 287, + 416 + ], + "spans": [ + { + "bbox": [ + 46, + 330, + 287, + 416 + ], + "type": "text", + "content": "One weakly-supervised variant of monocular 3D pose and shape estimation is learned from only 2D keypoint annotations. A common approach [3] is to estimate the MANO or SMPL parameters " + }, + { + "bbox": [ + 46, + 330, + 287, + 416 + ], + "type": "inline_equation", + "content": "(\\hat{\\theta},\\hat{\\beta})" + }, + { + "bbox": [ + 46, + 330, + 287, + 416 + ], + "type": "text", + "content": " for a given image and project the resulting 3D pose back into 2D joints " + }, + { + "bbox": [ + 46, + 330, + 287, + 416 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{j}}" + }, + { + "bbox": [ + 46, + 330, + 287, + 416 + ], + "type": "text", + "content": ", as per Eq. (1). The parameters can be learned with ground-truth 2D joints " + }, + { + "bbox": [ + 46, + 330, + 287, + 416 + ], + "type": "inline_equation", + "content": "\\mathbf{j}" + }, + { + "bbox": [ + 46, + 330, + 287, + 416 + ], + "type": "text", + "content": " by minimizing the following objective:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 92, + 421, + 287, + 437 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 92, + 421, + 287, + 437 + ], + "spans": [ + { + "bbox": [ + 92, + 421, + 287, + 437 + ], + "type": "interline_equation", + "content": "\\mathcal {L} = \\left\\| \\mathbf {j} - \\hat {\\mathbf {j}} \\right\\| _ {1} + \\lambda_ {\\theta} \\mathcal {R} (\\hat {\\theta}) + \\lambda_ {\\beta} \\| \\hat {\\beta} \\| _ {2} ^ {2}, \\tag {2}", + "image_path": "9418cc00963a5d50a5688de87876e9ae3153bd042177324b89eec8c23dddd3b8.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "spans": [ + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "text", + "content": "featuring a 2D reconstruction loss, a prior term " + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "inline_equation", + "content": "\\mathcal{R}(\\cdot)" + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "text", + "content": " on " + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "text", + "content": " to encourage feasible poses, an " + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "inline_equation", + "content": "l_{2}" + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "text", + "content": " regularization on " + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "text", + "content": ", and weighting hyperparameters " + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "inline_equation", + "content": "\\lambda_{\\theta}" + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "inline_equation", + "content": "\\lambda_{\\beta}" + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "text", + "content": ". The pose prior " + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "inline_equation", + "content": "\\mathcal{R}(\\cdot)" + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "text", + "content": " could be adversarial prior for rotation representations [16] or an " + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "inline_equation", + "content": "l_{2}" + }, + { + "bbox": [ + 46, + 443, + 287, + 504 + ], + "type": "text", + "content": " regularization for PCA coefficients [33]." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 510, + 155, + 523 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 510, + 155, + 523 + ], + "spans": [ + { + "bbox": [ + 47, + 510, + 155, + 523 + ], + "type": "text", + "content": "3.3. Normalizing Flow" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "spans": [ + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "text", + "content": "Normalizing Flows [32] are generative models with strong modeling capacity for complex, multi-modal distributions. Let " + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "inline_equation", + "content": "\\mathbf{X}" + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "text", + "content": " denote a " + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "text", + "content": "-dimensional random variable under distribution " + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "inline_equation", + "content": "P(\\mathbf{X})" + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "text", + "content": ". The normalizing flow model represents " + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "inline_equation", + "content": "\\mathbf{X}" + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "text", + "content": " as a series of invertible mappings " + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "inline_equation", + "content": "\\{f_l\\}_{l=1}^L: \\mathbb{R}^d \\mapsto \\mathbb{R}^d" + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "text", + "content": " on " + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "text", + "content": "-dimensional random variable " + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "inline_equation", + "content": "\\mathbf{Z}" + }, + { + "bbox": [ + 46, + 528, + 287, + 599 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 94, + 607, + 287, + 621 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 94, + 607, + 287, + 621 + ], + "spans": [ + { + "bbox": [ + 94, + 607, + 287, + 621 + ], + "type": "interline_equation", + "content": "\\mathbf {X} = \\mathcal {F} (\\mathbf {Z}) = f _ {L} \\circ \\dots \\circ f _ {2} \\circ f _ {1} (\\mathbf {Z}). \\tag {3}", + "image_path": "500844c9e2cd5db587dfbd6e48b9035183ef7b48f39e94e00050d4aaa4d430d4.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 628, + 287, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 628, + 287, + 676 + ], + "spans": [ + { + "bbox": [ + 46, + 628, + 287, + 676 + ], + "type": "text", + "content": "Typically, the base distribution " + }, + { + "bbox": [ + 46, + 628, + 287, + 676 + ], + "type": "inline_equation", + "content": "P(\\mathbf{Z})" + }, + { + "bbox": [ + 46, + 628, + 287, + 676 + ], + "type": "text", + "content": " is simple, e.g., a normal distribution " + }, + { + "bbox": [ + 46, + 628, + 287, + 676 + ], + "type": "inline_equation", + "content": "\\mathcal{N}(\\mathbf{0},\\mathbf{I})" + }, + { + "bbox": [ + 46, + 628, + 287, + 676 + ], + "type": "text", + "content": ". By some specially designed structures of flow blocks [8] and the change-of-variable rule [8], we can get the log-probability density of " + }, + { + "bbox": [ + 46, + 628, + 287, + 676 + ], + "type": "inline_equation", + "content": "\\mathbf{X}" + }, + { + "bbox": [ + 46, + 628, + 287, + 676 + ], + "type": "text", + "content": " as:" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 70, + 683, + 287, + 716 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 683, + 287, + 716 + ], + "spans": [ + { + "bbox": [ + 70, + 683, + 287, + 716 + ], + "type": "interline_equation", + "content": "\\log P (\\mathbf {X}) = \\log P (\\mathbf {Z}) - \\sum_ {l = 1} ^ {L} \\log \\left| \\det \\frac {\\partial f _ {l}}{\\partial \\mathbf {Z} _ {l - 1}} \\right|, \\tag {4}", + "image_path": "6f73fd3cc600c6b731cb93da9fcb1ea925417a53385295111bc56bd2726ec675.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "text", + "content": "where, " + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "\\mathbf{Z}_l = f_l(\\mathbf{Z}_{l-1}), \\mathbf{Z}_0 = \\mathbf{Z}" + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "\\mathbf{Z}_L = \\mathbf{X}" + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "text", + "content": ". Normalizing flows estimate the likelihood with the reverse flow " + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "\\mathcal{F}^{-1}(\\mathbf{X})" + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "text", + "content": " transforming " + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "\\mathbf{X}" + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "\\mathbf{Z}" + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "text", + "content": ". For sampling, it first samples " + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "\\mathbf{z}" + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "P(\\mathbf{Z})" + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "text", + "content": ", and passes " + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "\\mathbf{z}" + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "text", + "content": " through the flow " + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "text", + "content": " to get " + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 305, + 72, + 545, + 180 + ], + "type": "text", + "content": ". Normalizing flows are favoured as generative models because they can tractably estimate the exact likelihood and be optimized through Maximum Likelihood Estimation (MLE). Furthermore, they can also be optimized by sampling through the Law of the Unconscious Statistician (LOTUS)." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 189, + 476, + 203 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 189, + 476, + 203 + ], + "spans": [ + { + "bbox": [ + 306, + 189, + 476, + 203 + ], + "type": "text", + "content": "3.4. Principle of Maximum Entropy" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 208, + 545, + 233 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 208, + 545, + 233 + ], + "spans": [ + { + "bbox": [ + 306, + 208, + 545, + 233 + ], + "type": "text", + "content": "The entropy of random variable " + }, + { + "bbox": [ + 306, + 208, + 545, + 233 + ], + "type": "inline_equation", + "content": "\\mathbf{X}" + }, + { + "bbox": [ + 306, + 208, + 545, + 233 + ], + "type": "text", + "content": " taking values in " + }, + { + "bbox": [ + 306, + 208, + 545, + 233 + ], + "type": "inline_equation", + "content": "\\mathcal{X}" + }, + { + "bbox": [ + 306, + 208, + 545, + 233 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 306, + 208, + 545, + 233 + ], + "type": "inline_equation", + "content": "H(\\mathbf{X})" + }, + { + "bbox": [ + 306, + 208, + 545, + 233 + ], + "type": "text", + "content": ", quantifies the uncertainty of " + }, + { + "bbox": [ + 306, + 208, + 545, + 233 + ], + "type": "inline_equation", + "content": "\\mathbf{X}" + }, + { + "bbox": [ + 306, + 208, + 545, + 233 + ], + "type": "text", + "content": ". It is defined as:" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 358, + 243, + 545, + 269 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 358, + 243, + 545, + 269 + ], + "spans": [ + { + "bbox": [ + 358, + 243, + 545, + 269 + ], + "type": "interline_equation", + "content": "H (\\mathbf {X}) = - \\int_ {\\mathcal {X}} p (\\mathbf {x}) \\log p (\\mathbf {x}) d \\mathbf {x}. \\tag {5}", + "image_path": "857dd7aaa3f3c68dd98e6fb494f5a9f72b922d8da7bc7cb039218fc0634591fa.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 277, + 545, + 313 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 277, + 545, + 313 + ], + "spans": [ + { + "bbox": [ + 305, + 277, + 545, + 313 + ], + "type": "text", + "content": "Methods such as heuristic objectives [26] and mutual information [13, 23] have been proposed to estimate and optimize entropy." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 305, + 314, + 546, + 470 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 314, + 546, + 470 + ], + "spans": [ + { + "bbox": [ + 305, + 314, + 546, + 470 + ], + "type": "text", + "content": "Under the principle of maximum entropy [10], the probability distribution that most accurately reflects the current state of the system is the one with the highest entropy. In the context of 3D pose and shape estimation, the distribution should be compatible with complete observations, i.e. visible joints, but otherwise be as unbiased as possible for incomplete or ambiguous observations to maximize the entropy. This prevents unnecessary information from being assumed inadvertently. Especially, entropy maximization has garnered significant attention on efficient learning e.g., self-supervised learning [1, 29] and semi-supervised learning [24]. It is used to remove inadvertent assumptions and encourage the model to explore the full set of prototypes." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 482, + 389, + 496 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 482, + 389, + 496 + ], + "spans": [ + { + "bbox": [ + 306, + 482, + 389, + 496 + ], + "type": "text", + "content": "4. Methodology" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 306, + 502, + 384, + 514 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 502, + 384, + 514 + ], + "spans": [ + { + "bbox": [ + 306, + 502, + 384, + 514 + ], + "type": "text", + "content": "4.1. Framework" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "spans": [ + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "text", + "content": "We target multi-hypothesis 3D pose and shape recovery from RGB inputs based on visible 2D keypoints. Consider training instances " + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\{I, \\mathbf{j}, \\mathbf{v}\\}" + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "text", + "content": " is the RGB image, " + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{j}" + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "text", + "content": " is the corresponding visible 2D keypoints, and " + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{v}" + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "text", + "content": " is an indicator variable for 2D keypoints visibility. In line with previous works [22, 25, 26], we treat the shape parameter " + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "text", + "content": " and camera parameters " + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{c}" + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "text", + "content": " deterministically and assume that they can be estimated reasonably from " + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 305, + 521, + 545, + 616 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": "Our main interest then is to model the distribution of the pose parameter " + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": ", conditioned on the input image " + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": " with associated " + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{j}, \\beta" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{c}" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": ", i.e., the conditional distribution " + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "p(\\theta | I, \\mathbf{j}, \\mathbf{c}, \\beta)" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": ", which we refer to as the data distribution. To model the data distribution, we learn a model " + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\phi" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": " in the form of a neural network. Similarly, the model " + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\phi" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": " has the distribution " + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "p_{\\phi}(\\theta | I, \\mathbf{j}, \\mathbf{c}, \\beta)" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": ", which we term as the model distribution. The model " + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\phi" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": " can be learned by minimizing the" + } + ] + } + ], + "index": 23 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "14842" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 70, + 547, + 218 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 547, + 218 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 547, + 218 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 547, + 218 + ], + "type": "image", + "image_path": "64d911b38798484e99284aec0d75a3e340b21e6e42b2d9e22c47226a48c044bc.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 235, + 546, + 269 + ], + "lines": [ + { + "bbox": [ + 46, + 235, + 546, + 269 + ], + "spans": [ + { + "bbox": [ + 46, + 235, + 546, + 269 + ], + "type": "text", + "content": "Figure 2. Framework overview. The framework is optimized by considering three components: reconstruction, prior, and entropy (see the red double-headed arrows). The distribution of the feasible pose parameters is captured by an NF model conditioned on image features. The reconstruction applies different distributions for the visible keypoints (blue dots) and occluded keypoints (red dots)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 288, + 287, + 312 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 288, + 287, + 312 + ], + "spans": [ + { + "bbox": [ + 47, + 288, + 287, + 312 + ], + "type": "text", + "content": "Kullback-Leibler (KL) divergence between the data and the model distribution, i.e.," + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 93, + 322, + 287, + 335 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 93, + 322, + 287, + 335 + ], + "spans": [ + { + "bbox": [ + 93, + 322, + 287, + 335 + ], + "type": "interline_equation", + "content": "K L \\left(p _ {\\phi} (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta) \\| p (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta)\\right). \\tag {6}", + "image_path": "9581dc2c43403986383d186ea4e45bbb9e9df5a8fd5a9a919f38d702f80ec54f.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "spans": [ + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "type": "text", + "content": "Data Distribution. Inspired by the existing 2D-to-3D lifting works [7, 25, 26] that a 3D pose could be accurately estimated by its corresponding 2D pose, " + }, + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "type": "text", + "content": " and camera information, we assume that once " + }, + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{j},\\mathbf{c},\\beta \\}" + }, + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "type": "text", + "content": " are given, " + }, + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "type": "text", + "content": " are conditionally independent. As such, " + }, + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 350, + 287, + 434 + ], + "type": "text", + "content": " can be omitted as a conditioning variable. With Bayes' rule, the data distribution can be split as:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 61, + 443, + 287, + 456 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 443, + 287, + 456 + ], + "spans": [ + { + "bbox": [ + 61, + 443, + 287, + 456 + ], + "type": "interline_equation", + "content": "p (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta) = p (\\theta | \\mathbf {j}, \\mathbf {c}, \\beta) \\propto p (\\mathbf {j} | \\mathbf {c}, \\beta , \\theta) \\cdot p (\\theta). \\tag {7}", + "image_path": "9093d8b184daf227c4c0e132c79ef57137003b82a81db684c4d18959b51ae3a8.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 466, + 287, + 515 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 466, + 287, + 515 + ], + "spans": [ + { + "bbox": [ + 46, + 466, + 287, + 515 + ], + "type": "text", + "content": "The first decomposed term in Eq. (7), the likelihood " + }, + { + "bbox": [ + 46, + 466, + 287, + 515 + ], + "type": "inline_equation", + "content": "p(\\mathbf{j}|\\mathbf{c},\\beta ,\\theta)" + }, + { + "bbox": [ + 46, + 466, + 287, + 515 + ], + "type": "text", + "content": ", is a projection consistency term that reflects the reconstruction accuracy. The second term, " + }, + { + "bbox": [ + 46, + 466, + 287, + 515 + ], + "type": "inline_equation", + "content": "p(\\theta)" + }, + { + "bbox": [ + 46, + 466, + 287, + 515 + ], + "type": "text", + "content": ", serves as a general pose prior in a probabilistic perspective [16, 21]." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "spans": [ + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "type": "text", + "content": "Model Distribution. Like previous works [22, 16, 21, 2], we estimate " + }, + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "type": "text", + "content": " from an image " + }, + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "type": "text", + "content": ", as the image contains sufficient information to infer " + }, + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "type": "inline_equation", + "content": "\\mathbf{c}" + }, + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "type": "text", + "content": " and the keypoints " + }, + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "type": "inline_equation", + "content": "\\mathbf{j}" + }, + { + "bbox": [ + 46, + 529, + 287, + 578 + ], + "type": "text", + "content": ". The model distribution can be simplified as:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 111, + 588, + 287, + 601 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 588, + 287, + 601 + ], + "spans": [ + { + "bbox": [ + 111, + 588, + 287, + 601 + ], + "type": "interline_equation", + "content": "p _ {\\phi} (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta) = p _ {\\phi} (\\theta | I). \\tag {8}", + "image_path": "aac457bcd55f4b80017abb777b76c342057a7afd866962f9e798088652ce4adc.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 611, + 287, + 635 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 611, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 47, + 611, + 287, + 635 + ], + "type": "text", + "content": "Based on Eqs. (7) and (8), the KL divergence between the model and data distributions can be expressed as:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 50, + 644, + 298, + 712 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 50, + 644, + 298, + 712 + ], + "spans": [ + { + "bbox": [ + 50, + 644, + 298, + 712 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} K L \\left(p _ {\\phi} (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta) \\| p (\\theta | I, \\mathbf {j}, \\mathbf {c}, \\beta)\\right) = \\\\ - \\left(\\underbrace {\\underbrace {E _ {p _ {\\phi} (\\theta \\mid I)} [ \\log p (\\mathbf {j} \\mid \\mathbf {c} , \\beta , \\theta) ]} _ {\\text {r e c o n s t r u c t i o n}} + \\underbrace {E _ {p _ {\\phi} (\\theta \\mid I)} [ \\log p (\\theta) ]} _ {\\text {p r i o r}} + \\underbrace {H \\left(p _ {\\phi} (\\theta \\mid I)\\right)} _ {\\text {e n t r o p y}}\\right), \\tag {9} \\\\ \\end{array}", + "image_path": "462859b11d6ef5a9b388e8bda207ac502c95bc40b68a80807129c19cea782473.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "spans": [ + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "type": "inline_equation", + "content": "H(p_{\\phi}(\\theta |I)) = -E_{p_{\\phi}(\\theta |I)}[\\log p_{\\phi}(\\theta |I)]" + }, + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "type": "text", + "content": " is the entropy of " + }, + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "type": "text", + "content": " given input image " + }, + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "type": "text", + "content": ". See Suppl. B for the full derivation. Minimizing the KL divergence in Eq. (9) maximizes the reconstruction accuracy and the conditional entropy of the pose under pose prior " + }, + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "type": "inline_equation", + "content": "p(\\theta)" + }, + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "type": "text", + "content": "; this can be used directly to supervise the neural network " + }, + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "type": "inline_equation", + "content": "\\phi" + }, + { + "bbox": [ + 304, + 287, + 545, + 359 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "spans": [ + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "type": "text", + "content": "Based on the above derivation, we propose a weakly-supervised multi-hypothesis framework as illustrated in Fig. 2. We consider only visible 2D keypoints as supervisory signals for the reconstruction. Like [21, 26], we assume that visible keypoints follow a Laplace distribution for sharpness. In line with the principle of maximum entropy (Sec. 3.4), the occluded keypoints each follow a uniform distribution of feasible locations. The intuition behind such an assumption is that, for occluded keypoints, we relax the supervision using prior knowledge " + }, + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "type": "inline_equation", + "content": "p(\\theta)" + }, + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "type": "text", + "content": " to generate feasible solutions for the image. This prevents an overconfident model that tries to fit all labels regardless of visibility and also compensates for the lack of one-to-many data-label pairs. As " + }, + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "type": "text", + "content": " is derived from a parametric model, the prior can be applied simply as a uniform distribution [33] or adversarially [16] based on its representation. We choose to model the distribution " + }, + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "type": "inline_equation", + "content": "p_{\\phi}(\\theta |I)" + }, + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "type": "text", + "content": " using a conditional NF model, i.e., " + }, + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "type": "inline_equation", + "content": "p_{\\phi}(\\theta |I) = \\mathcal{F}^{-1}(\\theta |I)" + }, + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "type": "text", + "content": ", as it is more feasible to calculate the entropy term " + }, + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "type": "inline_equation", + "content": "H(p_{\\phi}(\\theta |I))" + }, + { + "bbox": [ + 304, + 363, + 546, + 614 + ], + "type": "text", + "content": " via Monte Carlo (MC) sampling. Therefore, all three terms in Eq. (9) can be maximized by MC sampling and SGD [18]." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": "An important part of our formulation involves the explicit maximization of entropy. The link between entropy and diverse hypotheses is highly intuitive, yet this has been overlooked in previous work. Even without one-to-many labels, the entropy term encourages the model " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\phi" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": " to generate hypotheses that are diverse; the reconstruction and prior term ensure that the hypotheses respect the observed labels while remaining feasible." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "14843" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 180, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 180, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 180, + 85 + ], + "type": "text", + "content": "4.2. Implementation Details" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 91, + 287, + 139 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 91, + 287, + 139 + ], + "spans": [ + { + "bbox": [ + 47, + 91, + 287, + 139 + ], + "type": "text", + "content": "In Eq. (9), we represent image " + }, + { + "bbox": [ + 47, + 91, + 287, + 139 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 47, + 91, + 287, + 139 + ], + "type": "text", + "content": " with image features extracted from a ResNet-50 [12] backbone. To estimate " + }, + { + "bbox": [ + 47, + 91, + 287, + 139 + ], + "type": "inline_equation", + "content": "\\mathbf{c}" + }, + { + "bbox": [ + 47, + 91, + 287, + 139 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 91, + 287, + 139 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 47, + 91, + 287, + 139 + ], + "type": "text", + "content": ", we append a 512-hidden unit MLP to the backbone. For the normalizing flow model, we use the Real NVP[8]." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 139, + 287, + 188 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 139, + 287, + 188 + ], + "spans": [ + { + "bbox": [ + 47, + 139, + 287, + 188 + ], + "type": "text", + "content": "First, to obtain " + }, + { + "bbox": [ + 47, + 139, + 287, + 188 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 47, + 139, + 287, + 188 + ], + "type": "text", + "content": " for an image, according to LOTUS, we sample " + }, + { + "bbox": [ + 47, + 139, + 287, + 188 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_0" + }, + { + "bbox": [ + 47, + 139, + 287, + 188 + ], + "type": "text", + "content": " from a Gaussian distribution and feed it together with image feature of " + }, + { + "bbox": [ + 47, + 139, + 287, + 188 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 47, + 139, + 287, + 188 + ], + "type": "text", + "content": " to the invertible flow network " + }, + { + "bbox": [ + 47, + 139, + 287, + 188 + ], + "type": "inline_equation", + "content": "\\mathcal{F}(\\mathbf{z}|I)" + }, + { + "bbox": [ + 47, + 139, + 287, + 188 + ], + "type": "text", + "content": " (the solid line in the yellow block in Fig. 2)." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 204, + 287, + 241 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 204, + 287, + 241 + ], + "spans": [ + { + "bbox": [ + 47, + 204, + 287, + 241 + ], + "type": "text", + "content": "Reconstruction. We use a constant scale " + }, + { + "bbox": [ + 47, + 204, + 287, + 241 + ], + "type": "inline_equation", + "content": "b" + }, + { + "bbox": [ + 47, + 204, + 287, + 241 + ], + "type": "text", + "content": " for the Laplace and assume the joints do not exceed the large occlusion range (Suppl. B.2); the reconstruction loss simplifies to:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 115, + 251, + 287, + 283 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 115, + 251, + 287, + 283 + ], + "spans": [ + { + "bbox": [ + 115, + 251, + 287, + 283 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {r e c}} = \\sum_ {k = 1} ^ {K} v _ {k} \\| \\mathbf {j} _ {k} - \\hat {\\mathbf {j}} _ {k} \\| _ {1}, \\tag {10}", + "image_path": "0950e13dd3ee811937edc07000d3e2f25e6bd445822f66b6b37c93c6d14ffc25.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 293, + 287, + 328 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 293, + 287, + 328 + ], + "spans": [ + { + "bbox": [ + 47, + 293, + 287, + 328 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 293, + 287, + 328 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 47, + 293, + 287, + 328 + ], + "type": "text", + "content": " is the number of joints and " + }, + { + "bbox": [ + 47, + 293, + 287, + 328 + ], + "type": "inline_equation", + "content": "\\mathbf{j}_k" + }, + { + "bbox": [ + 47, + 293, + 287, + 328 + ], + "type": "text", + "content": " represents " + }, + { + "bbox": [ + 47, + 293, + 287, + 328 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 47, + 293, + 287, + 328 + ], + "type": "text", + "content": "-th joint; the loss is effective only on visible joints based on visibility indicator " + }, + { + "bbox": [ + 47, + 293, + 287, + 328 + ], + "type": "inline_equation", + "content": "v_k" + }, + { + "bbox": [ + 47, + 293, + 287, + 328 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 346, + 287, + 406 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 346, + 287, + 406 + ], + "spans": [ + { + "bbox": [ + 47, + 346, + 287, + 406 + ], + "type": "text", + "content": "Prior. To encourage feasible poses, we introduce a prior term " + }, + { + "bbox": [ + 47, + 346, + 287, + 406 + ], + "type": "inline_equation", + "content": "\\mathcal{R}(\\cdot)" + }, + { + "bbox": [ + 47, + 346, + 287, + 406 + ], + "type": "text", + "content": " on " + }, + { + "bbox": [ + 47, + 346, + 287, + 406 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 47, + 346, + 287, + 406 + ], + "type": "text", + "content": ". For MANO, " + }, + { + "bbox": [ + 47, + 346, + 287, + 406 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 47, + 346, + 287, + 406 + ], + "type": "text", + "content": " is given as PCA coefficients. We empirically place a uniform distribution " + }, + { + "bbox": [ + 47, + 346, + 287, + 406 + ], + "type": "inline_equation", + "content": "\\mathcal{R}(\\theta) = \\mathcal{U}(-2,2)" + }, + { + "bbox": [ + 47, + 346, + 287, + 406 + ], + "type": "text", + "content": " on these coefficients, which covers most feasible solutions while avoiding invalid poses [33], i.e.," + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 108, + 415, + 287, + 439 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 108, + 415, + 287, + 439 + ], + "spans": [ + { + "bbox": [ + 108, + 415, + 287, + 439 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\theta} = \\sum_ {i} \\max (0, | \\theta_ {i} | - 2) ^ {2}. \\tag {11}", + "image_path": "e3cc1cf64d162edd0343f00faf75cca70d3fbdf385d930f69251d6fc823718c1.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 449, + 287, + 474 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 449, + 287, + 474 + ], + "spans": [ + { + "bbox": [ + 47, + 449, + 287, + 474 + ], + "type": "text", + "content": "For SMPL, " + }, + { + "bbox": [ + 47, + 449, + 287, + 474 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 47, + 449, + 287, + 474 + ], + "type": "text", + "content": " represents axis-angle rotations and can be restricted by an adversarial prior [16], i.e.," + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 137, + 485, + 287, + 497 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 137, + 485, + 287, + 497 + ], + "spans": [ + { + "bbox": [ + 137, + 485, + 287, + 497 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\theta} = \\operatorname {A d v} (\\theta). \\tag {12}", + "image_path": "747604e3e3f2746e57ac858be6841310d28d38920a91769057beb6474c34de43.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 514, + 248, + 525 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 514, + 248, + 525 + ], + "spans": [ + { + "bbox": [ + 47, + 514, + 248, + 525 + ], + "type": "text", + "content": "Entropy. We use a negative log-likelihood loss:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 123, + 536, + 287, + 549 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 123, + 536, + 287, + 549 + ], + "spans": [ + { + "bbox": [ + 123, + 536, + 287, + 549 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {H} = - \\log p _ {\\phi} (\\theta | I), \\tag {13}", + "image_path": "eecb49d3800aac6650bf31b3b7c6f80e3ded96eb95471ee6da7fedfaf68ca14d.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 559, + 287, + 608 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 559, + 287, + 608 + ], + "spans": [ + { + "bbox": [ + 47, + 559, + 287, + 608 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 559, + 287, + 608 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 47, + 559, + 287, + 608 + ], + "type": "text", + "content": " is sampled from the normalizing flow. The reverse path of the NF, " + }, + { + "bbox": [ + 47, + 559, + 287, + 608 + ], + "type": "inline_equation", + "content": "\\mathcal{F}^{-1}(\\theta |I)" + }, + { + "bbox": [ + 47, + 559, + 287, + 608 + ], + "type": "text", + "content": ", maps " + }, + { + "bbox": [ + 47, + 559, + 287, + 608 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 47, + 559, + 287, + 608 + ], + "type": "text", + "content": " back to " + }, + { + "bbox": [ + 47, + 559, + 287, + 608 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_0" + }, + { + "bbox": [ + 47, + 559, + 287, + 608 + ], + "type": "text", + "content": " in the latent space conditional on the image features to compute Eq. (4) [8, 17] (dashed lines in the yellow block in Fig. 2)." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 47, + 609, + 286, + 643 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 609, + 286, + 643 + ], + "spans": [ + { + "bbox": [ + 47, + 609, + 286, + 643 + ], + "type": "text", + "content": "The losses in Eqs. (10)-(13) each covers a term in Eq. (9). With the " + }, + { + "bbox": [ + 47, + 609, + 286, + 643 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 47, + 609, + 286, + 643 + ], + "type": "text", + "content": " regularization in Eq. (2), all losses sum into the final training objective:" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 84, + 658, + 286, + 670 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 84, + 658, + 286, + 670 + ], + "spans": [ + { + "bbox": [ + 84, + 658, + 286, + 670 + ], + "type": "interline_equation", + "content": "\\mathcal {L} = \\lambda_ {\\text {r e c}} \\mathcal {L} _ {\\text {r e c}} + \\lambda_ {\\theta} \\mathcal {L} _ {\\theta} + \\lambda_ {H} \\mathcal {L} _ {H} + \\lambda_ {\\beta} \\mathcal {L} _ {\\beta}, \\tag {14}", + "image_path": "c06ed880664ccce7cf59befc53e676ad9da389583b88ebec98061102f53439e5.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": "where the " + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": "s are the trade-off hyperparameters and " + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\beta} = ||\\beta||_2^2" + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": ". See Suppl. B for the full derivations and more training details." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 72, + 386, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 386, + 85 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 386, + 85 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 91, + 470, + 102 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 91, + 470, + 102 + ], + "spans": [ + { + "bbox": [ + 306, + 91, + 470, + 102 + ], + "type": "text", + "content": "5.1. Datasets, Metrics, & Baselines" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 109, + 545, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 109, + 545, + 193 + ], + "spans": [ + { + "bbox": [ + 304, + 109, + 545, + 193 + ], + "type": "text", + "content": "Datasets. We synthesize a 2-joint toy setting in 2D to highlight components of our model. For the human body, we experiment on Human3.6M (H36M) [14] and its ambiguous version AH36M [2] with randomly truncated images of H36M to hide keypoints. Following [2, 21], we train with subjects S1 and S5-9 and test with S11, training with H36M and AH36M jointly, while evaluating separately." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 193, + 545, + 337 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 193, + 545, + 337 + ], + "spans": [ + { + "bbox": [ + 304, + 193, + 545, + 337 + ], + "type": "text", + "content": "Inspired by AH36M, we construct Ambiguous RHD (ARHD) from the synthetic hand pose dataset RHD [43] by adding circular patches with a predefined radius to the fingers' DIP joints1. The visibility in the scene is affected depending on the finger and circle radius (see Fig. 5(c)). We also use HO3D [11], a real-world hand-object dataset that features severe occlusions. To evaluate the multi-hypothesis metrics, similar to previous work [38], we split a test subset from the training dataset. We estimate the visibility of a joint [9] by thresholding the difference between captured surface depth and the true keypoint position. More details of the datasets are provided in Suppl. D." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 350, + 545, + 398 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 350, + 545, + 398 + ], + "spans": [ + { + "bbox": [ + 304, + 350, + 545, + 398 + ], + "type": "text", + "content": "Evaluation Metrics. Mean End-Point Error (EPE) is the average Euclidean distance between predicted and ground-truth joints, from which we consider the Best Hypothesis (BH) [25, 2] and our newly proposed All Hypothesis (AH)." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 399, + 545, + 457 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 399, + 545, + 457 + ], + "spans": [ + { + "bbox": [ + 304, + 399, + 545, + 457 + ], + "type": "text", + "content": "BH is a standard multi-hypothesis metric that selects the hypothesis with the lowest pose or mesh EPE. To evaluate the accuracy of all hypotheses, we propose AH, which is the mean EPE of all hypotheses on 2D visible joints to measure consistency to the image evidence." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 458, + 545, + 553 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 458, + 545, + 553 + ], + "spans": [ + { + "bbox": [ + 304, + 458, + 545, + 553 + ], + "type": "text", + "content": "As we highlighted, multiple hypotheses should be diverse, but the diversity should only be on uncertain joints e.g. under occlusion. However, existing BH and diversity metrics [34, 26] do not capture this target because undesirable diversity on the visible joints may also contribute to the diversity metrics. Therefore, we propose to complement the evaluation of multi-hypothesis methods with Per-Joint Diversity (PJD) and a Relative Diversity (RD) ratio." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 554, + 545, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 554, + 545, + 601 + ], + "spans": [ + { + "bbox": [ + 304, + 554, + 545, + 601 + ], + "type": "text", + "content": "PJD measures the standard deviation per joint and can be used to show the diversity of both visible and occluded joints in 2D and 3D spaces. To highlight the source of diversity, we propose a ratio:" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 389, + 606, + 544, + 632 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 389, + 606, + 544, + 632 + ], + "spans": [ + { + "bbox": [ + 389, + 606, + 544, + 632 + ], + "type": "interline_equation", + "content": "\\mathbf {R D} = \\frac {\\mathrm {P J D} _ {2 \\mathrm {d v i s}}}{\\mathrm {P J D} _ {3 \\mathrm {d o c c}}}, \\tag {15}", + "image_path": "5be56970d006aa1f73d8882c24aa2f6baa90e71cf8d426cd98846b2a8eaeb9cd.jpg" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 304, + 636, + 545, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 636, + 545, + 696 + ], + "spans": [ + { + "bbox": [ + 304, + 636, + 545, + 696 + ], + "type": "text", + "content": "to account for the diversity of both the certain (i.e., 2D visible keypoints) and the uncertain parts (i.e., 3D occluded keypoints). A lower RD means more diversity on the occluded keypoints relative to visible keypoints. We follow [35, 37] and sample 200 hypotheses for evaluation." + } + ] + } + ], + "index": 25 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 317, + 702, + 544, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 702, + 544, + 713 + ], + "spans": [ + { + "bbox": [ + 317, + 702, + 544, + 713 + ], + "type": "text", + "content": "1The distal interphalangeal (DIP) joint is the one closest to the fingertip." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "14844" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 72, + 140, + 137 + ], + "blocks": [ + { + "bbox": [ + 53, + 72, + 140, + 137 + ], + "lines": [ + { + "bbox": [ + 53, + 72, + 140, + 137 + ], + "spans": [ + { + "bbox": [ + 53, + 72, + 140, + 137 + ], + "type": "image", + "image_path": "4712b23c6425c22645cf52713a09d21e9a69e9646278d1e39d8af81972351fdb.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 89, + 140, + 102, + 148 + ], + "lines": [ + { + "bbox": [ + 89, + 140, + 102, + 148 + ], + "spans": [ + { + "bbox": [ + 89, + 140, + 102, + 148 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 140, + 72, + 214, + 137 + ], + "blocks": [ + { + "bbox": [ + 140, + 72, + 214, + 137 + ], + "lines": [ + { + "bbox": [ + 140, + 72, + 214, + 137 + ], + "spans": [ + { + "bbox": [ + 140, + 72, + 214, + 137 + ], + "type": "image", + "image_path": "1bf4de5afb661faf898de40284ed9eb3cca2dc8f78e6b885cd7eb71c0d971aa4.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 168, + 140, + 179, + 149 + ], + "lines": [ + { + "bbox": [ + 168, + 140, + 179, + 149 + ], + "spans": [ + { + "bbox": [ + 168, + 140, + 179, + 149 + ], + "type": "text", + "content": "(b)" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 216, + 72, + 279, + 137 + ], + "blocks": [ + { + "bbox": [ + 216, + 72, + 279, + 137 + ], + "lines": [ + { + "bbox": [ + 216, + 72, + 279, + 137 + ], + "spans": [ + { + "bbox": [ + 216, + 72, + 279, + 137 + ], + "type": "image", + "image_path": "35a9a440b2b7dd88061518a7fd845413e1787608d278b5ff1f8aeb30dad5bf14.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 241, + 140, + 252, + 149 + ], + "lines": [ + { + "bbox": [ + 241, + 140, + 252, + 149 + ], + "spans": [ + { + "bbox": [ + 241, + 140, + 252, + 149 + ], + "type": "text", + "content": "(c)" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 53, + 217, + 134, + 339 + ], + "blocks": [ + { + "bbox": [ + 46, + 151, + 287, + 205 + ], + "lines": [ + { + "bbox": [ + 46, + 151, + 287, + 205 + ], + "spans": [ + { + "bbox": [ + 46, + 151, + 287, + 205 + ], + "type": "text", + "content": "Figure 3. (a) Toy problem setting featuring four modes. (b) Our probabilistic method in a weakly supervised setting recovers all the modes. (c) The deterministic method, even under strong supervision, predicts wrong modes as it easily overfits ubiquitous observation noise." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 53, + 217, + 134, + 339 + ], + "lines": [ + { + "bbox": [ + 53, + 217, + 134, + 339 + ], + "spans": [ + { + "bbox": [ + 53, + 217, + 134, + 339 + ], + "type": "image", + "image_path": "f585497cb9d2991f6ed68443209a51ad5f62622bdb04f216cffa24e3efe6f2de.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 96, + 342, + 107, + 352 + ], + "lines": [ + { + "bbox": [ + 96, + 342, + 107, + 352 + ], + "spans": [ + { + "bbox": [ + 96, + 342, + 107, + 352 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 354, + 287, + 409 + ], + "lines": [ + { + "bbox": [ + 46, + 354, + 287, + 409 + ], + "spans": [ + { + "bbox": [ + 46, + 354, + 287, + 409 + ], + "type": "text", + "content": "Figure 4. (a) Lowering the weight of the entropy term can impair multi-mode learning while (b) increasing the weights hurts the fitting accuracy, although it achieves diversity. (c) Choosing different feasibility priors will also make the final learned modes different. The second row shows the mode distribution in " + }, + { + "bbox": [ + 46, + 354, + 287, + 409 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 354, + 287, + 409 + ], + "type": "text", + "content": " space." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 134, + 217, + 207, + 339 + ], + "blocks": [ + { + "bbox": [ + 134, + 217, + 207, + 339 + ], + "lines": [ + { + "bbox": [ + 134, + 217, + 207, + 339 + ], + "spans": [ + { + "bbox": [ + 134, + 217, + 207, + 339 + ], + "type": "image", + "image_path": "11c277106590209922fa0cea4d5f25567d19907eb5175fba3851e76fc872a1e4.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 169, + 342, + 181, + 352 + ], + "lines": [ + { + "bbox": [ + 169, + 342, + 181, + 352 + ], + "spans": [ + { + "bbox": [ + 169, + 342, + 181, + 352 + ], + "type": "text", + "content": "(b)" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 207, + 217, + 283, + 339 + ], + "blocks": [ + { + "bbox": [ + 207, + 217, + 283, + 339 + ], + "lines": [ + { + "bbox": [ + 207, + 217, + 283, + 339 + ], + "spans": [ + { + "bbox": [ + 207, + 217, + 283, + 339 + ], + "type": "image", + "image_path": "f40a56f853cca59e4aa5c1554420353bf8aa17c712a00fb106f6ae00ff340986.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 244, + 342, + 256, + 352 + ], + "lines": [ + { + "bbox": [ + 244, + 342, + 256, + 352 + ], + "spans": [ + { + "bbox": [ + 244, + 342, + 256, + 352 + ], + "type": "text", + "content": "(c)" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 430, + 287, + 527 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 430, + 287, + 527 + ], + "spans": [ + { + "bbox": [ + 46, + 430, + 287, + 527 + ], + "type": "text", + "content": "Baselines & SOTAs. We compare our method with two deterministic methods, Det (2D Vis) and Det (3D), which use visible 2D and all 3D keypoint positions as supervision, respectively. For more details, refer to a similar pipeline in [3]. Moreover, we compare our method with the state-of-the-art multi-hypothesis methods, including MDN [25], conditional VAE [35], Multi-bodies [2], ProHMR [21], CM-VAE [36] and WS3DPG [26]." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 46, + 528, + 287, + 598 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 528, + 287, + 598 + ], + "spans": [ + { + "bbox": [ + 46, + 528, + 287, + 598 + ], + "type": "text", + "content": "Some of these approaches are designed with 3D pose supervision; we replace their corresponding supervised losses with the 2D version in Eq. (2). Unless specified, we also use visibility labels as weights while remaining as faithful as possible to the original method. See Suppl. F for method introductions and details." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 47, + 609, + 242, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 609, + 242, + 623 + ], + "spans": [ + { + "bbox": [ + 47, + 609, + 242, + 623 + ], + "type": "text", + "content": "5.2. Toy Experiments & Ablation Studies" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "content": "Settings. We perform the toy experiment under a simple setting (depth ambiguity), as shown in Fig. 3(a). Consider a single chain with two keypoints plus a root keypoint. The bones are fixed to length 1 and the root is at the origin. The data " + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "(\\mathbf{y},\\alpha)" + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "content": " consists of the 1D projection " + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "y_{k}" + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "content": " of the keypoint on the y-axis and the angle " + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\alpha_{k}" + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "content": " between the chain and the y-axis. From " + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\alpha_{k}" + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "content": ", we can get 2D coordinates" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "inline_equation", + "content": "\\mathbf{j}_k = (\\sin \\alpha_k, \\cos \\alpha_k)" + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "text", + "content": " relative to their parent. There are in total four Gaussian modes for the complete data, i.e., each joint can swing left and right. The model is trained to predict " + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "text", + "content": " based on " + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "text", + "content": ". For weak supervision, only 1D projections " + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "text", + "content": " are given. For strong supervision, all 2D coordinates " + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "inline_equation", + "content": "\\mathbf{j}" + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "text", + "content": " are provided. Our model uses an MLP and Real NVP as the backbone and optimizes an objective similar to Eq. (14). For the prior loss, we add an " + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "inline_equation", + "content": "L_2" + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "text", + "content": " norm constraint on " + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 72, + 545, + 168 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 186, + 545, + 270 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 186, + 545, + 270 + ], + "spans": [ + { + "bbox": [ + 304, + 186, + 545, + 270 + ], + "type": "text", + "content": "Deterministic vs. Multi-Hypothesis. The deterministic model trained under both weak and strong supervision can learn only one of the four modes. Moreover, under strong supervision, it is sensitive to similar input data and predicts wrong modes if the inputs are corrupted with small perturbations (Fig. 3(c)). In contrast, existing multi-hypothesis methods can recover all modes under strong supervision." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 289, + 545, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 289, + 545, + 361 + ], + "spans": [ + { + "bbox": [ + 304, + 289, + 545, + 361 + ], + "type": "text", + "content": "Ours vs. Existing Multi-Hypothesis Methods. Existing methods require similar observations with multiple distinct ground-truth poses. In the weakly supervised setting, we compare with MDN and observe that it finds only one of the modes (Suppl. G.1) while our proposed method can successfully recover all the modes (Fig. 3(b))." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 379, + 545, + 487 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 379, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 304, + 379, + 545, + 487 + ], + "type": "text", + "content": "Reconstruction vs. Entropy. The entropy term encourages the set of predictions to cover diverse solutions while maintaining a low reconstruction error. As the weight of the entropy term " + }, + { + "bbox": [ + 304, + 379, + 545, + 487 + ], + "type": "inline_equation", + "content": "\\lambda_{H}" + }, + { + "bbox": [ + 304, + 379, + 545, + 487 + ], + "type": "text", + "content": " decreases, the objective emphasizes reconstruction at the cost of entropy, leading to missed modes (Fig. 4(a)). The extreme is the degradation to a deterministic model. On the other hand, with the increase in " + }, + { + "bbox": [ + 304, + 379, + 545, + 487 + ], + "type": "inline_equation", + "content": "\\lambda_{H}" + }, + { + "bbox": [ + 304, + 379, + 545, + 487 + ], + "type": "text", + "content": ", the model pays less attention to reconstructing observed evidence, hence the modes become dispersed (Fig. 4(b))." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 505, + 545, + 625 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 505, + 545, + 625 + ], + "spans": [ + { + "bbox": [ + 304, + 505, + 545, + 625 + ], + "type": "text", + "content": "Angle Prior. The prior term determines the distribution over the feasible solution space. When we lower the weight of the prior loss, the model may fit the evidence better but consider less feasible poses. On the other hand, prior knowledge defines the solution space, and the entropy term will encourage the predictions to cover all possible solutions based on the prior. For example, when we add a prior " + }, + { + "bbox": [ + 304, + 505, + 545, + 625 + ], + "type": "inline_equation", + "content": "\\sin \\alpha_{k} \\geq 0" + }, + { + "bbox": [ + 304, + 505, + 545, + 625 + ], + "type": "text", + "content": " for the top keypoints, some previous modes become infeasible and the model will only find two of the four original poses (Fig. 4(c))." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 306, + 634, + 456, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 634, + 456, + 647 + ], + "spans": [ + { + "bbox": [ + 306, + 634, + 456, + 647 + ], + "type": "text", + "content": "5.3. Synthetic Ambiguous RHD" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "Deterministic vs. Multi-Hypothesis. Table 1(a) shows that on ARHD, all the multi-hypothesis methods [25, 35, 26, 21, 37] outperform the deterministic 'Det (2D Vis)' on the BH metric. Some methods even outperform the 'Det (3D)' baseline with 3D supervision." + } + ] + } + ], + "index": 24 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "14845" + } + ] + } + ], + "index": 25 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 54, + 70, + 541, + 201 + ], + "blocks": [ + { + "bbox": [ + 54, + 70, + 541, + 201 + ], + "lines": [ + { + "bbox": [ + 54, + 70, + 541, + 201 + ], + "spans": [ + { + "bbox": [ + 54, + 70, + 541, + 201 + ], + "type": "table", + "html": "
ARHDHO3D
BH (mm)↓ JointAH (pix)↓PJDRD↓BH (mm)↓ JointAH (pix)↓PJDRD↓
2D Vis3D Occ2D Vis3D Occ
Det (3D) [44]20.98----23.8825.18---
Det (2D Vis)25.1114.39---24.1025.4016.85--
Multi-bodies [2]20.5215.763.505.980.5922.0723.5619.571.920.62
MDN [25]21.3318.477.1412.690.5621.2822.6718.813.480.56
CVAE [35]20.9919.957.0210.660.6621.0422.6218.904.070.61
ProHMR [21]24.4413.370.130.220.5924.0525.4117.190.160.64
CM-VAE [36]21.9916.595.6710.400.5522.2023.5418.394.940.57
WS3DPG [26]24.3417.794.617.390.6223.6724.9918.343.060.65
Ours20.3513.423.8614.420.2720.5521.8316.953.300.28
", + "image_path": "c43eedc5f9888a5d2ea68a372519d8afd42c6282d60d81ab874048127b913e37.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 201, + 546, + 224 + ], + "lines": [ + { + "bbox": [ + 46, + 201, + 546, + 224 + ], + "spans": [ + { + "bbox": [ + 46, + 201, + 546, + 224 + ], + "type": "text", + "content": "Table 1. Quantitative results on ARHD and HO3D V3. The best is marked in bold; the second best is underlined. Our method achieves competitive SOTA results; occluded keypoints are diverse while visible ones are relatively accurate, i.e., have a lower RD." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "type": "image", + "bbox": [ + 50, + 242, + 202, + 360 + ], + "blocks": [ + { + "bbox": [ + 50, + 242, + 202, + 360 + ], + "lines": [ + { + "bbox": [ + 50, + 242, + 202, + 360 + ], + "spans": [ + { + "bbox": [ + 50, + 242, + 202, + 360 + ], + "type": "image", + "image_path": "eb100ef281def04bd3b48b79441da824319bae60226fbb1fe5aef52c9828e6e9.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 65, + 365, + 192, + 375 + ], + "lines": [ + { + "bbox": [ + 65, + 365, + 192, + 375 + ], + "spans": [ + { + "bbox": [ + 65, + 365, + 192, + 375 + ], + "type": "text", + "content": "(a) RD: 2D Vis PJD - 3D Occ PJD" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 200, + 242, + 360, + 361 + ], + "blocks": [ + { + "bbox": [ + 200, + 242, + 360, + 361 + ], + "lines": [ + { + "bbox": [ + 200, + 242, + 360, + 361 + ], + "spans": [ + { + "bbox": [ + 200, + 242, + 360, + 361 + ], + "type": "image", + "image_path": "8565b98b46b71b67be7e83037f96cc19f3da2eeb44fd454d30d4450cfcf11670.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 236, + 365, + 347, + 375 + ], + "lines": [ + { + "bbox": [ + 236, + 365, + 347, + 375 + ], + "spans": [ + { + "bbox": [ + 236, + 365, + 347, + 375 + ], + "type": "text", + "content": "(b) PJD Curve Along Training" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 45, + 387, + 547, + 444 + ], + "lines": [ + { + "bbox": [ + 45, + 387, + 547, + 444 + ], + "spans": [ + { + "bbox": [ + 45, + 387, + 547, + 444 + ], + "type": "text", + "content": "Figure 5. Illustration on ARHD. (a) Deviation from the diagonal (dashed line) towards the lower-right indicates a better trade-off between the 2D visible accuracy and 3D occluded diversity. (b) Comparison of PJD during learning for occluded (solid line) and visible (dashed line) keypoints. Our approach has a descending trend for visible keypoints and an ascending trend for the occluded ones. (c) Multi-hypothesis meshes. The red boxes highlight the concerned occluded keypoints. Our method predicts diverse and feasible poses under occlusion while MDN's predictions are inconsistent with image evidence on visible keypoints." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 365, + 239, + 543, + 357 + ], + "blocks": [ + { + "bbox": [ + 365, + 239, + 543, + 357 + ], + "lines": [ + { + "bbox": [ + 365, + 239, + 543, + 357 + ], + "spans": [ + { + "bbox": [ + 365, + 239, + 543, + 357 + ], + "type": "image", + "image_path": "c37cdbc126cdd9baf11e5010788b63840dc6b751c50a7652c3f3ff8157067a5a.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 418, + 365, + 500, + 375 + ], + "lines": [ + { + "bbox": [ + 418, + 365, + 500, + 375 + ], + "spans": [ + { + "bbox": [ + 418, + 365, + 500, + 375 + ], + "type": "text", + "content": "(c) Qualitative Results" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 462, + 287, + 581 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 462, + 287, + 581 + ], + "spans": [ + { + "bbox": [ + 46, + 462, + 287, + 581 + ], + "type": "text", + "content": "Comparisons with SOTA. Methods like MDN [25] and CVAE [35] all have low BH (Tab. 1(a)). However, their diversity (PJD) for visible and occluded keypoints is high, i.e., the entire hand is diverse. Together with a large AH, this suggests that their hypotheses as a whole do not fit the image evidence well. ProHMR [21] degenerates to an almost deterministic method, and has the lowest PJD for visible and occluded keypoints. We speculate that it is because of its reliance on the strong supervision for " + }, + { + "bbox": [ + 46, + 462, + 287, + 581 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 462, + 287, + 581 + ], + "type": "text", + "content": " labels. More comparisons can be found in Sec. 5.5." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 583, + 288, + 654 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 583, + 288, + 654 + ], + "spans": [ + { + "bbox": [ + 46, + 583, + 288, + 654 + ], + "type": "text", + "content": "In contrast, our framework obtains lower BH and AH and higher occluded diversity (higher " + }, + { + "bbox": [ + 46, + 583, + 288, + 654 + ], + "type": "inline_equation", + "content": "\\mathrm{PJD}_{\\mathrm{occ}}" + }, + { + "bbox": [ + 46, + 583, + 288, + 654 + ], + "type": "text", + "content": " and thus significantly lower RD). Fig. 5(a) shows that we strike a good balance between reconstruction and diversity; qualitatively, Fig. 5(c) shows that our recovered meshes are diverse and consistent with the observation." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "content": "Connection to Existing Works & Ablation Studies. ProHMR [21], CM-VAE [36], and WS3DPG [26] are closely related to our method. Among them, ProHMR" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 462, + 545, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 462, + 545, + 594 + ], + "spans": [ + { + "bbox": [ + 304, + 462, + 545, + 594 + ], + "type": "text", + "content": "is a variant without entropy optimization; CM-VAE [36] applies a single Gaussian distribution instead of our NF; WS3DPG [26] uses a GAN whose entropy is intractable. Tab. 1(a) shows that our entropy term increases the PJD significantly, especially for occluded joints in 3D (ProHMR's 0.22 vs. our 14.42). Moreover, we outperform CM-VAE and WS3DPG on all metrics on ARHD, showing the powerful ability of NFs to model complex distributions and estimate entropy. Additional ablations on visibility in Suppl. G.2 shows that adding additional supervision on occluded joints hurts diversity." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 617, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 546, + 713 + ], + "type": "text", + "content": "PJD During Training. Fig. 5(b) shows the test PJD scores throughout training. The PJD of MDN [25] for both visible and occluded keypoints decreases as training progresses. Meanwhile, CVAE [35] has the opposite trend, with increasing PJD scores for both types of keypoints. In contrast, our approach has a descending trend on the PJD of visible keypoints and an ascending trend on the occluded ones (Tab. 1(a))." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "text", + "content": "14846" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 72, + 282, + 157 + ], + "blocks": [ + { + "bbox": [ + 51, + 72, + 282, + 157 + ], + "lines": [ + { + "bbox": [ + 51, + 72, + 282, + 157 + ], + "spans": [ + { + "bbox": [ + 51, + 72, + 282, + 157 + ], + "type": "image", + "image_path": "544d4b0e682ae6d49f9d06d387ef5e5e81da719102965c4f285cdac949f74e66.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 171, + 270, + 182 + ], + "lines": [ + { + "bbox": [ + 47, + 171, + 270, + 182 + ], + "spans": [ + { + "bbox": [ + 47, + 171, + 270, + 182 + ], + "type": "text", + "content": "Figure 6. Visualization of our multiple hypotheses on HO3D." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 47, + 194, + 284, + 269 + ], + "blocks": [ + { + "bbox": [ + 47, + 194, + 284, + 269 + ], + "lines": [ + { + "bbox": [ + 47, + 194, + 284, + 269 + ], + "spans": [ + { + "bbox": [ + 47, + 194, + 284, + 269 + ], + "type": "image", + "image_path": "255b6c6bc03ce4fd58a307d5c86609122933c87da8459cd2b6399b737d472f99.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 288, + 287, + 322 + ], + "lines": [ + { + "bbox": [ + 46, + 288, + 287, + 322 + ], + "spans": [ + { + "bbox": [ + 46, + 288, + 287, + 322 + ], + "type": "text", + "content": "Figure 7. Visualization of hypotheses with the smallest and largest HOI Chamfer distance in two views. Differences are highlighted with red boxes. Hypothesis selection leads to more feasible grasps." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 48, + 332, + 284, + 435 + ], + "blocks": [ + { + "bbox": [ + 48, + 332, + 284, + 435 + ], + "lines": [ + { + "bbox": [ + 48, + 332, + 284, + 435 + ], + "spans": [ + { + "bbox": [ + 48, + 332, + 284, + 435 + ], + "type": "image", + "image_path": "9395993369b957f7e871b35ddba189b68803fe229b26a19f2ca6eb1aa7a77daa.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 453, + 287, + 487 + ], + "lines": [ + { + "bbox": [ + 46, + 453, + 287, + 487 + ], + "spans": [ + { + "bbox": [ + 46, + 453, + 287, + 487 + ], + "type": "text", + "content": "Figure 8. Qualitative results on AH36M. The legs of our hypotheses are much more diverse, while all trunks are consistent with the image. The green mesh is the ground-truth." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 507, + 188, + 519 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 507, + 188, + 519 + ], + "spans": [ + { + "bbox": [ + 47, + 507, + 188, + 519 + ], + "type": "text", + "content": "5.4. Real-World Data: HO3D" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 526, + 287, + 587 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 526, + 287, + 587 + ], + "spans": [ + { + "bbox": [ + 46, + 526, + 287, + 587 + ], + "type": "text", + "content": "When faced with real-world ambiguous settings, such as objects occluding hands, our method is state-of-the-art compared to other multi-hypothesis methods. The results in Tab. 1(b) and Fig. 6 are consistent with the trends on the synthetic ARHD – our method has the lowest BH and RD." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "content": "Hypothesis Selection. With additional input information, the multiple hypotheses can be filtered for an improved set of solutions. We show an example of hypothesis selection in which we select feasible grasps based on the object interaction. We simply use a post-processing strategy to select samples. Specifically, we use a hand-object interaction (HOI) feasibility metric, e.g., the widely used Chamfer distance [4]. Based on the value of the Chamfer distance, we can select hypotheses. We found it useful for picking" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 72, + 547, + 145 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 145 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 145 + ], + "type": "text", + "content": "more plausible poses from hypotheses using task-related constraints. We visualize hypotheses with the lowest and highest HOI Chamfer distance in Fig. 7. Our hypotheses are all consistent with the image cues in the front camera view. From a different view, by incorporating the HOI constraint for hypotheses, we can select more feasible grasp poses." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 159, + 546, + 280 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 159, + 546, + 280 + ], + "spans": [ + { + "bbox": [ + 304, + 159, + 546, + 280 + ], + "type": "text", + "content": "Meaningful Diversity. The purpose of our method is to encourage meaningful diversity; hence we treat visible and occluded joints differently. The quality of diversity can be further improved by incorporating more information about the observed ambiguity. One example is to add mask information about the occlusions; it can be incorporated into our framework as a post-hoc hypothesis selection during inference or as a reconstruction loss in Eq. (9) during training. In both ways, the error rate for out-of-occlusion can therefore be reduced without much loss in diversity (Suppl. G.2)." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 287, + 506, + 300 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 287, + 506, + 300 + ], + "spans": [ + { + "bbox": [ + 306, + 287, + 506, + 300 + ], + "type": "text", + "content": "5.5. State-of-The-Art on H36M & AH36M" + } + ] + } + ], + "index": 11 + }, + { + "type": "table", + "bbox": [ + 321, + 314, + 531, + 434 + ], + "blocks": [ + { + "bbox": [ + 321, + 314, + 531, + 434 + ], + "lines": [ + { + "bbox": [ + 321, + 314, + 531, + 434 + ], + "spans": [ + { + "bbox": [ + 321, + 314, + 531, + 434 + ], + "type": "table", + "html": "
SupervisionMHH36MAH36M
2D VisHMR67.485.2
ProHMR✓64.382.6
Ours✓51.366.4
3DHMR56.8-
SPIN41.1-
MDN✓42.769.5
CVAE✓46.275.1
Multi-bodies✓42.264.2
ProHMR✓36.860.1
Ours✓36.850.6
", + "image_path": "cb7b76a9e0a926a2e8e3d532e17b211247a920d002e81aca90cc365970c933d7.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_body" + } + ], + "index": 12 + }, + { + "type": "table", + "bbox": [ + 309, + 489, + 545, + 555 + ], + "blocks": [ + { + "bbox": [ + 306, + 434, + 545, + 468 + ], + "lines": [ + { + "bbox": [ + 306, + 434, + 545, + 468 + ], + "spans": [ + { + "bbox": [ + 306, + 434, + 545, + 468 + ], + "type": "text", + "content": "Table 2. PA-MPJPE (mm) of BH results on H36M and its ambiguous version AH36M under the supervision of visible 2D keypoints (2D Vis) and 3D keypoints (3D) with " + }, + { + "bbox": [ + 306, + 434, + 545, + 468 + ], + "type": "inline_equation", + "content": "n = 25" + }, + { + "bbox": [ + 306, + 434, + 545, + 468 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 309, + 489, + 545, + 555 + ], + "lines": [ + { + "bbox": [ + 309, + 489, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 309, + 489, + 545, + 555 + ], + "type": "table", + "html": "
SupervisionAH (pix)↓PJDRD↓
2D Vis3D Occ
2D VisProHMR10.920.060.260.23
Ours9.754.5664.050.07
3DProHMR13.383.9824.270.16
Ours10.734.2347.950.09
", + "image_path": "bc2b3b59b83e226cea4a91429147807c1e8ef550fc9cd28fb707559270a6654c.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "table_body" + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 557, + 545, + 580 + ], + "lines": [ + { + "bbox": [ + 306, + 557, + 545, + 580 + ], + "spans": [ + { + "bbox": [ + 306, + 557, + 545, + 580 + ], + "type": "text", + "content": "Table 3. Diversity metrics on AH36M under the supervision of visible 2D keypoints (2D Vis) and 3D keypoints (3D)." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 594, + 545, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 545, + 677 + ], + "type": "text", + "content": "Our framework is also effective for human pose estimation. We follow [2, 21] and evaluate the accuracy and diversity of hypotheses on the benchmark H36M and its ambiguous version AH36M. Besides using 2D visible keypoints as supervision, we also test a variant using 3D keypoints. For supervision with 3D keypoints, we follow ProHMR [21] and supervise the predicted 3D poses from SMPL directly." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "content": "Tab. 2 shows that we achieve the best BH on both datasets with different supervision settings. Our method has an impressive " + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "inline_equation", + "content": "9.5\\mathrm{mm}" + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "content": " improvement on AH36M with 3D" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "14847" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 145 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 145 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 145 + ], + "type": "text", + "content": "keypoints as labels; furthermore, our performance with 2D visible keypoints as weak labels is comparable to using 3D keypoints as labels. Comparing diversity metrics in Tab. 3 and Fig. 8, we outperform ProHMR with respect to AH and RD. Our method with the entropy term predicts highly diverse results in the weakly-supervised setting." + } + ] + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 80, + 156, + 255, + 201 + ], + "blocks": [ + { + "bbox": [ + 80, + 156, + 255, + 201 + ], + "lines": [ + { + "bbox": [ + 80, + 156, + 255, + 201 + ], + "spans": [ + { + "bbox": [ + 80, + 156, + 255, + 201 + ], + "type": "table", + "html": "
H36MAH36M
Multi-ViewFittingFitting
ProHMR34.534.861.4
Ours34.234.453.5
", + "image_path": "7ca74eb89a126bf8c6bbf589dd51e663d76483228989c0690d744f2940f54698.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 201, + 288, + 245 + ], + "lines": [ + { + "bbox": [ + 46, + 201, + 288, + 245 + ], + "spans": [ + { + "bbox": [ + 46, + 201, + 288, + 245 + ], + "type": "text", + "content": "Table 4. PA-MPJPE (mm) of downstream tasks multi-view refinement and fitting humans with 2D ground-truth. For these tasks, a trained model distribution outputs only one hypothesis by observing more evidence." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 277, + 287, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 277, + 287, + 361 + ], + "spans": [ + { + "bbox": [ + 46, + 277, + 287, + 361 + ], + "type": "text", + "content": "Downstream Tasks. Our method, by estimating an accurate yet diverse set of hypotheses, excels at providing inputs for downstream tasks. We verify the hypotheses through multi-view refinement and fitting humans with 2D ground-truth on H36M and AH36M. We follow ProHMR to find the solution that best matches the evidence among many possible hypotheses by optimization, i.e.," + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 110, + 373, + 287, + 390 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 373, + 287, + 390 + ], + "spans": [ + { + "bbox": [ + 110, + 373, + 287, + 390 + ], + "type": "interline_equation", + "content": "\\max _ {\\theta} \\log p _ {\\phi} (\\theta | I) + c (\\theta | \\mathbf {e}), \\tag {16}", + "image_path": "d758813809796be4d325c14ea7940d8f417afb00358509cb1781ae368cc7c969.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 401, + 287, + 462 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 401, + 287, + 462 + ], + "spans": [ + { + "bbox": [ + 46, + 401, + 287, + 462 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 401, + 287, + 462 + ], + "type": "inline_equation", + "content": "c(\\theta | \\mathbf{e})" + }, + { + "bbox": [ + 46, + 401, + 287, + 462 + ], + "type": "text", + "content": " is consistency with additional information, e.g., multi-view and 2D projection consistency. Lower PA-MPJPE in Tab. 4 verifies our effectiveness, which may imply ours obtains a better representation with a more accurate distribution than ProHMR." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 475, + 190, + 489 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 475, + 190, + 489 + ], + "spans": [ + { + "bbox": [ + 47, + 475, + 190, + 489 + ], + "type": "text", + "content": "6. Discussion & Conclusion" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 497, + 287, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 497, + 287, + 605 + ], + "spans": [ + { + "bbox": [ + 46, + 497, + 287, + 605 + ], + "type": "text", + "content": "Our proposed multi-hypothesis framework is flexible, efficient, and label-friendly. We emphasize that diversity in the hypotheses should not be arbitrary; instead, it should come from ambiguity present in the image itself. To that end, we also propose a more comprehensive evaluation scheme based on visibility. In our work, we have only considered ambiguity from object occlusions and image truncations, but additional factors such as image quality and light are interesting directions to investigate for future work." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "content": "We note that by virtue of evaluating on the provided annotations of the current datasets, the diversity concept remains vague and limited to the dataset. For instance, in-distribution testing aims to learn the pose diversity captured in that dataset. It may not require learning more diverse outdoor poses to achieve a good BH on indoor datasets and thus not conducive to generalization to other scenarios. It is suggested to focus more on the improvement and evaluation of the diversity in the generalization scenario." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": "Acknowledgments. This research/project is supported by the Ministry of Education, Singapore, under its MOE Academic Research Fund Tier 2 (STEM RIE2025 MOET2EP20220-0015). We would also like to thank the ACs, reviewers, Dr. Chen Li, and Junpeng Hu for their valuable suggestions." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 307, + 155, + 365, + 167 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 155, + 365, + 167 + ], + "spans": [ + { + "bbox": [ + 307, + 155, + 365, + 167 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 307, + 174, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 26, + "blocks": [ + { + "bbox": [ + 311, + 174, + 545, + 218 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 174, + 545, + 218 + ], + "spans": [ + { + "bbox": [ + 311, + 174, + 545, + 218 + ], + "type": "text", + "content": "[1] Mahmoud Assran, Mathilde Caron, Ishan Misra, Piotr Bojanowski, Florian Bordes, Pascal Vincent, Armand Joulin, Mike Rabbat, and Nicolas Ballas. Masked siamese networks for label-efficient learning. In ECCV, 2022. 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 311, + 219, + 545, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 219, + 545, + 262 + ], + "spans": [ + { + "bbox": [ + 311, + 219, + 545, + 262 + ], + "type": "text", + "content": "[2] Benjamin Biggs, David Novotny, Sebastien Ehrhardt, Hanbyul Joo, Ben Graham, and Andrea Vedaldi. 3D Multibodies: Fitting sets of plausible 3D human models to ambiguous image data. In NeurIPS, 2020. 1, 2, 4, 5, 6, 7, 8" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 311, + 264, + 545, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 264, + 545, + 297 + ], + "spans": [ + { + "bbox": [ + 311, + 264, + 545, + 297 + ], + "type": "text", + "content": "[3] Adnane Boukhayma, Rodrigo de Bem, and Philip HS Torr. 3D hand shape and pose from images in the wild. In CVPR, 2019. 1, 2, 3, 6" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 311, + 298, + 545, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 298, + 545, + 330 + ], + "spans": [ + { + "bbox": [ + 311, + 298, + 545, + 330 + ], + "type": "text", + "content": "[4] Zhe Cao, Ilija Radosavovic, Angjoo Kanazawa, and Jitendra Malik. Reconstructing hand-object interactions in the wild. In ICCV, 2021. 8" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 311, + 331, + 545, + 375 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 331, + 545, + 375 + ], + "spans": [ + { + "bbox": [ + 311, + 331, + 545, + 375 + ], + "type": "text", + "content": "[5] Ping Chen, Yujin Chen, Dong Yang, Fangyin Wu, Qin Li, Qingpei Xia, and Yong Tan. I2UV-HandNet: Image-to-UV prediction network for accurate and high-fidelity 3D hand mesh modeling. In ICCV, 2021. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 311, + 376, + 545, + 409 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 376, + 545, + 409 + ], + "spans": [ + { + "bbox": [ + 311, + 376, + 545, + 409 + ], + "type": "text", + "content": "[6] Zerui Chen, Yana Hasson, Cordelia Schmid, and Ivan Laptev. AlignSDF: Pose-aligned signed distance fields for hand-object reconstruction. In ECCV, 2022. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 311, + 410, + 545, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 410, + 545, + 453 + ], + "spans": [ + { + "bbox": [ + 311, + 410, + 545, + 453 + ], + "type": "text", + "content": "[7] Hongsuk Choi, Gyeongsik Moon, and Kyoung Mu Lee. Pose2Mesh: Graph convolutional network for 3D human pose and mesh recovery from a 2D human pose. In ECCV, 2020. 1, 4" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 311, + 455, + 545, + 476 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 455, + 545, + 476 + ], + "spans": [ + { + "bbox": [ + 311, + 455, + 545, + 476 + ], + "type": "text", + "content": "[8] Laurent Dinh, Jascha Sohl-Dickstein, and Samy Bengio. Density estimation using real NVP. In ICLR, 2017. 3, 5" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 311, + 478, + 545, + 499 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 478, + 545, + 499 + ], + "spans": [ + { + "bbox": [ + 311, + 478, + 545, + 499 + ], + "type": "text", + "content": "[9] Kerui Gu, Linlin Yang, and Angela Yao. Removing the bias of integral pose regression. In ICCV, 2021. 5" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 501, + 545, + 522 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 501, + 545, + 522 + ], + "spans": [ + { + "bbox": [ + 307, + 501, + 545, + 522 + ], + "type": "text", + "content": "[10] Silviu Guiasu and Abe Shenitzer. The principle of maximum entropy. Math. Intell., 7(1):42-48, 1985. 2, 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 523, + 545, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 523, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 307, + 523, + 545, + 555 + ], + "type": "text", + "content": "[11] Shreyas Hampali, Mahdi Rad, Markus Oberweger, and Vincent Lepetit. HOnnotate: A method for 3D annotation of hand and object poses. In CVPR, 2020. 5" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 557, + 545, + 590 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 557, + 545, + 590 + ], + "spans": [ + { + "bbox": [ + 307, + 557, + 545, + 590 + ], + "type": "text", + "content": "[12] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, 2016. 5" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 591, + 545, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 591, + 545, + 634 + ], + "spans": [ + { + "bbox": [ + 307, + 591, + 545, + 634 + ], + "type": "text", + "content": "[13] R Devon Hjelm, Alex Fedorov, Samuel Lavoie-Marchildon, Karan Grewal, Phil Bachman, Adam Trischler, and Yoshua Bengio. Learning deep representations by mutual information estimation and maximization. In ICLR, 2019. 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 635, + 545, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 635, + 545, + 678 + ], + "spans": [ + { + "bbox": [ + 307, + 635, + 545, + 678 + ], + "type": "text", + "content": "[14] Catalin Ionescu, Dragos Papava, Vlad Olaru, and Cristian Sminchisescu. Human3.6M: Large scale datasets and predictive methods for 3D human sensing in natural environments. TPAMI, 36(7):1325-1339, 2013. 5" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 680, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 680, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 680, + 545, + 713 + ], + "type": "text", + "content": "[15] Umar Iqbal, Pavlo Molchanov, Thomas Breuel Juergen Gall, and Jan Kautz. Hand pose estimation via latent 2.5D heatmap regression. In ECCV, 2018. 1" + } + ] + } + ], + "index": 25 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "14848" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 18, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "type": "text", + "content": "[16] Angjoo Kanazawa, Michael J Black, David W Jacobs, and Jitendra Malik. End-to-end recovery of human shape and pose. In CVPR, 2018. 2, 3, 4, 5" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 287, + 129 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 287, + 129 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 287, + 129 + ], + "type": "text", + "content": "[17] Durk P Kingma and Prafulla Dhariwal. Glow: Generative flow with invertible 1x1 convolutions. In NeurIPS, 2018. 5" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 130, + 287, + 152 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 130, + 287, + 152 + ], + "spans": [ + { + "bbox": [ + 48, + 130, + 287, + 152 + ], + "type": "text", + "content": "[18] Diederik P. Kingma and Max Welling. Auto-encoding variational Bayes. In ICLR, 2014. 4" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 153, + 287, + 185 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 153, + 287, + 185 + ], + "spans": [ + { + "bbox": [ + 48, + 153, + 287, + 185 + ], + "type": "text", + "content": "[19] Muhammed Kocabas, Nikos Athanasiou, and Michael J Black. VIBE: Video inference for human body pose and shape estimation. In CVPR, 2020. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 186, + 287, + 219 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 186, + 287, + 219 + ], + "spans": [ + { + "bbox": [ + 48, + 186, + 287, + 219 + ], + "type": "text", + "content": "[20] Nikos Kolotouros, Georgios Pavlakos, Michael J Black, and Kostas Daniilidis. Learning to reconstruct 3D human pose and shape via model-fitting in the loop. In ICCV, 2019. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 220, + 287, + 253 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 220, + 287, + 253 + ], + "spans": [ + { + "bbox": [ + 48, + 220, + 287, + 253 + ], + "type": "text", + "content": "[21] Nikos Kolotouros, Georgios Pavlakos, Dinesh Jayaraman, and Kostas Daniilidis. Probabilistic modeling for human mesh recovery. In ICCV, 2021. 1, 2, 4, 5, 6, 7, 8" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 255, + 287, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 255, + 287, + 297 + ], + "spans": [ + { + "bbox": [ + 48, + 255, + 287, + 297 + ], + "type": "text", + "content": "[22] Dominik Kulon, Riza Alp Guler, Iasonas Kokkinos, Michael M Bronstein, and Stefanos Zafeiriou. Weakly-supervised mesh-convolutional hand reconstruction in the wild. In CVPR, 2020. 2, 3, 4" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 299, + 287, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 299, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 48, + 299, + 287, + 342 + ], + "type": "text", + "content": "[23] Rithesh Kumar, Sherjil Ozair, Anirudh Goyal, Aaron Courville, and Yoshua Bengio. Maximum entropy generators for energy-based models. In arXiv:1901.08508, 2019. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 343, + 287, + 387 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 343, + 287, + 387 + ], + "spans": [ + { + "bbox": [ + 48, + 343, + 287, + 387 + ], + "type": "text", + "content": "[24] Jogendra Nath Kundu, Siddharth Seth, Pradyumna YM, Varun Jampani, Anirban Chakraborty, and R Venkatesh Babu. Uncertainty-aware adaptation for self-supervised 3d human pose estimation. In CVPR, 2022. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 388, + 287, + 421 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 388, + 287, + 421 + ], + "spans": [ + { + "bbox": [ + 48, + 388, + 287, + 421 + ], + "type": "text", + "content": "[25] Chen Li and Gim Hee Lee. Generating multiple hypotheses for 3D human pose estimation with mixture density network. In CVPR, 2019. 1, 2, 3, 4, 5, 6, 7" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 422, + 287, + 454 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 422, + 287, + 454 + ], + "spans": [ + { + "bbox": [ + 48, + 422, + 287, + 454 + ], + "type": "text", + "content": "[26] Chen Li and Gim Hee Lee. Weakly supervised generative network for multiple 3D human pose hypotheses. In BMVC, 2020. 1, 3, 4, 5, 6, 7" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 456, + 287, + 488 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 456, + 287, + 488 + ], + "spans": [ + { + "bbox": [ + 48, + 456, + 287, + 488 + ], + "type": "text", + "content": "[27] Wenhao Li, Hong Liu, Hao Tang, Pichao Wang, and Luc Van Gool. MHFormer: Multi-hypothesis transformer for 3D human pose estimation. In CVPR, 2022. 1" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 490, + 287, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 490, + 287, + 521 + ], + "spans": [ + { + "bbox": [ + 48, + 490, + 287, + 521 + ], + "type": "text", + "content": "[28] Kevin Lin, Lijuan Wang, and Zicheng Liu. End-to-end human pose and mesh reconstruction with transformers. In CVPR, 2021. 1, 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 523, + 287, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 523, + 287, + 555 + ], + "spans": [ + { + "bbox": [ + 48, + 523, + 287, + 555 + ], + "type": "text", + "content": "[29] Xin Liu, Zhongdao Wang, Ya-Li Li, and Shengjin Wang. Self-supervised learning via maximum entropy coding. 2022. 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 557, + 287, + 590 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 557, + 287, + 590 + ], + "spans": [ + { + "bbox": [ + 48, + 557, + 287, + 590 + ], + "type": "text", + "content": "[30] Matthew Loper, Naureen Mahmood, Javier Romero, Gerard Pons-Moll, and Michael J Black. SMPL: A skinned multiperson linear model. TOG, 34(6):1-16, 2015. 2, 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 591, + 287, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 591, + 287, + 634 + ], + "spans": [ + { + "bbox": [ + 48, + 591, + 287, + 634 + ], + "type": "text", + "content": "[31] Gyeongsik Moon and Kyoung Mu Lee. I2L-MeshNet: Image-to-lixel prediction network for accurate 3D human pose and mesh estimation from a single RGB image. In ECCV, 2020. 1, 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 636, + 287, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 636, + 287, + 679 + ], + "spans": [ + { + "bbox": [ + 48, + 636, + 287, + 679 + ], + "type": "text", + "content": "[32] George Papamakarios, Eric T Nalisnick, Danilo Jimenez Rezende, Shakir Mohamed, and Balaji Lakshminarayanan. Normalizing flows for probabilistic modeling and inference. JMLR, 22(57):1-64, 2021. 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "type": "text", + "content": "[33] Javier Romero, Dimitrios Tzionas, and Michael J. Black. Embodied Hands: Modeling and capturing hands and bodies together. TOG, 36(6):1-17, 2017. 2, 3, 4, 5" + } + ] + } + ], + "index": 17 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 488 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "text", + "content": "[34] Akash Sengupta, Ignas Budvytis, and Roberto Cipolla. Hierarchical kinematic probability distributions for 3D human shape and pose estimation from images in the wild. In ICCV, 2021. 5" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 118, + 545, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 545, + 161 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 545, + 161 + ], + "type": "text", + "content": "[35] Saurabh Sharma, Pavan Teja Varigonda, Prashast Bindal, Abhishek Sharma, and Arjun Jain. Monocular 3D human pose estimation by generation and ordinal ranking. In ICCV, 2019. 1, 2, 5, 6, 7" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 163, + 545, + 195 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 163, + 545, + 195 + ], + "spans": [ + { + "bbox": [ + 307, + 163, + 545, + 195 + ], + "type": "text", + "content": "[36] Adrian Spurr, Jie Song, Seonwook Park, and Otmar Hilliges. Cross-modal deep variational hand pose estimation. In CVPR, 2018. 6, 7" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 197, + 545, + 229 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 197, + 545, + 229 + ], + "spans": [ + { + "bbox": [ + 307, + 197, + 545, + 229 + ], + "type": "text", + "content": "[37] Tom Wehrbein, Marco Rudolph, Bodo Rosenhahn, and Bastian Wandt. Probabilistic monocular 3D human pose estimation with normalizing flows. In ICCV, 2021. 1, 2, 5, 6" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 231, + 545, + 263 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 231, + 545, + 263 + ], + "spans": [ + { + "bbox": [ + 307, + 231, + 545, + 263 + ], + "type": "text", + "content": "[38] Lixin Yang, Xinyu Zhan, Kailin Li, Wenqiang Xu, Jiefeng Li, and Cewu Lu. CPF: Learning a contact potential field to model the hand-object interaction. In ICCV, 2021. 5" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 265, + 545, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 265, + 545, + 297 + ], + "spans": [ + { + "bbox": [ + 307, + 265, + 545, + 297 + ], + "type": "text", + "content": "[39] Qi Ye and Tae-Kyun Kim. Occlusion-aware hand pose estimation using hierarchical mixture density network. In ECCV, 2018. 1, 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 298, + 545, + 331 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 298, + 545, + 331 + ], + "spans": [ + { + "bbox": [ + 307, + 298, + 545, + 331 + ], + "type": "text", + "content": "[40] Ziwei Yu, Linlin Yang, You Xie, Ping Chen, and Angela Yao. UV-based 3D hand-object reconstruction with grasp optimization. In BMVC, 2022. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 332, + 545, + 376 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 332, + 545, + 376 + ], + "spans": [ + { + "bbox": [ + 307, + 332, + 545, + 376 + ], + "type": "text", + "content": "[41] Andrei Zanfir, Eduard Gabriel Bazavan, Hongyi Xu, William T Freeman, Rahul Sukthankar, and Cristian Sminchisescu. Weakly supervised 3D human pose and shape reconstruction with normalizing flows. In ECCV, 2020. 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 377, + 545, + 410 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 377, + 545, + 410 + ], + "spans": [ + { + "bbox": [ + 307, + 377, + 545, + 410 + ], + "type": "text", + "content": "[42] Wang Zeng, Wanli Ouyang, Ping Luo, Wentao Liu, and Xiaogang Wang. 3D human mesh regression with dense correspondence. In CVPR, 2020. 2" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 411, + 545, + 442 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 411, + 545, + 442 + ], + "spans": [ + { + "bbox": [ + 307, + 411, + 545, + 442 + ], + "type": "text", + "content": "[43] Christian Zimmermann and Thomas Brox. Learning to estimate 3D hand pose from single RGB images. In ICCV, 2017. 5" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 445, + 545, + 488 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 445, + 545, + 488 + ], + "spans": [ + { + "bbox": [ + 307, + 445, + 545, + 488 + ], + "type": "text", + "content": "[44] Christian Zimmermann, Duygu Ceylan, Jimei Yang, Bryan Russell, Max Argus, and Thomas Brox. FreiHAND: A dataset for markerless capture of hand pose and shape from single RGB images. In ICCV, 2019. 7" + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "14849" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/af22c1bd-1590-4032-ac12-a1b776021514_content_list.json b/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/af22c1bd-1590-4032-ac12-a1b776021514_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..ba7deb1ff6488f5e93ec4fb4e1718d9deb224c6c --- /dev/null +++ b/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/af22c1bd-1590-4032-ac12-a1b776021514_content_list.json @@ -0,0 +1,1703 @@ +[ + { + "type": "text", + "text": "MI-GAN: A Simple Baseline for Image Inpainting on Mobile Devices", + "text_level": 1, + "bbox": [ + 137, + 130, + 833, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Andranik Sargsyan1, Shant Navasardyan1, Xingqian Xu1,2, Humphrey Shi1,2", + "bbox": [ + 181, + 179, + 785, + 199 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1Picsart AI Research (PAIR), 2SHI Labs @ Georgia Tech, Oregon & UIUC", + "bbox": [ + 259, + 200, + 709, + 215 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/bb7f114aaaa5bbefa86f556e4e918b2e2aa20967b6a906441865aab834372745.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 80, + 268, + 238, + 352 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/d164b12f6472219fbe504753207c4b1de06f28efe3ecd28b8c4a6cba9ded6416.jpg", + "image_caption": [ + "Figure 1. The proposed approach can produce plausible results both on complex scene images as well as on face images. The scene image inputs are taken from the Places 2 [67] dataset and the face image input is from FFHQ [27] dataset. The bubble chart on the right shows the advantage of our network over state-of-the-art approaches. The size of the bubble signifies the relative number of parameters of each approach and the number inside of the bubble shows the absolute number of model parameters. Our approach achieves a low FID, while being one order of magnitude smaller and faster than recent SOTA approaches." + ], + "image_footnote": [], + "bbox": [ + 80, + 352, + 238, + 436 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/c0b63dbc8b9bf868f66c6546977f827871e09d743224dad746c7ddcfde2c0dc5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 240, + 268, + 429, + 352 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/91cec3edb59fd48ace1155d068b8240420028b6f710ca15b23eb4c8141329c5b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 240, + 352, + 429, + 436 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/4b708583e9b5bb964222019fb8c6a00928ced8705384dabb79cca5e94ed7ae76.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 431, + 268, + 540, + 352 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/4dc6b2c7f714cd9b3140f35ec68dd5f656fcdf3fea890da7b31b8a2e3eda18c1.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 431, + 352, + 540, + 436 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/bb3d5645c9c902fb69dee7f881a042fdeb08dec6c747afad0bbabff5baa6c6cb.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 544, + 268, + 890, + 436 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 529, + 313, + 544 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In recent years, many deep learning based image inpainting methods have been developed by the research community. Some of those methods have shown impressive image completion abilities. Yet, to the best of our knowledge, there is no image inpainting model designed to run on mobile devices. In this paper we present a simple image inpainting baseline, Mobile Inpainting GAN (MI-GAN), which is approximately one order of magnitude computationally cheaper and smaller than existing state-of-the-art inpainting models, and can be efficiently deployed on mobile devices. Excessive quantitative and qualitative evaluations show that MI-GAN performs comparable or, in some cases, better than recent state-of-the-art approaches. Moreover, we perform a user study comparing MI-GAN results with results from several commercial mobile inpainting applications, which clearly shows the advantage of MI-GAN in comparison to existing apps. With the purpose of high quality and efficient inpainting, we utilize an effective combination of adversarial training, model reparametrization, and knowledge distillation. Our models and code are publicly available at https://github.com/Picsart-AI-Research/MI-GAN.", + "bbox": [ + 75, + 570, + 473, + 902 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 500, + 573, + 630, + 589 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The task of image inpainting is to complete the missing regions in images in a realistic and visually plausible way. Image inpainting algorithms have found their applications in such problems as image restoration, removal of unwanted objects, etc.", + "bbox": [ + 496, + 598, + 890, + 672 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Nowadays, in the era of fast evolving gadgets, particularly smartphones, image/video editing applications are growing furiously. The usage of mobile devices for making creative visual content by professionals as well as by consumers shows a great increasing tendency. A lot of mobile applications such as Photoshop Express [24], Picsart [25], Snapseed [39], TouchRetouch [18] empower the users to create awesome content utilizing AI-powered tools. One of the most popular such tools, object remover, allows its users to remove unwanted objects (e.g. watermarks, lines, people or random objects in the background, etc.) from their photos. So millions of users every day benefit from image inpainting technologies integrated in various mobile applications.", + "bbox": [ + 496, + 675, + 892, + 883 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Current AI-based state-of-the-art inpainting algorithms", + "bbox": [ + 517, + 886, + 890, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "7335", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "such as Co-Mod-GAN [65], SH-GAN [58], LaMa [53], or LDM [46] include an inference of a heavyweight neural network, which is often not feasible to do on low-end mobile devices (see Tables 1, 2). Therefore the processing is being done on server-side resulting in dependency on Internet connection, speed, traffic and server usage costs for image editing companies.", + "bbox": [ + 75, + 90, + 468, + 196 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To address this problem we propose a simple baseline for high-quality mobile image inpainting which is an order of magnitude lighter and computationally more efficient than current state-of-the-art neural networks while showing similar or sometimes even better performance (see Fig. 1).", + "bbox": [ + 75, + 196, + 468, + 272 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Motivated by the generative nature of the image completion problem we design MI-GAN, Mobile Inpainting Generative Adversarial Network, which benefits from a hybrid system consisting of adversarial training, model reparametrization, and knowledge distillation. Thanks to adversarial nature of the MI-GAN training, image completion results appear to be visually plausible without producing blurry regions and pattern-like artifacts. Model reparametrization further increases the output quality at no cost of efficiency. Finally, knowledge distillation by a stronger network also improves the generative ability of MI-GAN.", + "bbox": [ + 75, + 272, + 467, + 450 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Due to excessive evaluations MI-GAN shows great performance in terms of both quantitative and qualitative comparison with existing state-of-the-art methods.", + "bbox": [ + 76, + 454, + 467, + 498 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To summarize, our contributions are three-fold.", + "bbox": [ + 96, + 500, + 408, + 512 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose MI-GAN, to the best of our knowledge the first mobile generative image inpainting network.", + "- We develop a customized knowledge distillation method that is suitable for our model and problem, as well as we implement a model re-parametrization strategy which enhances the quality of results.", + "- While being computationally more efficient and lighter than the existing state-of-the-art image completion approaches, MI-GAN produces similar or even better image inpainting results. Furthermore, in comparison to existing commercial mobile inpainting applications, MI-GAN results are generally rated higher by human evaluators." + ], + "bbox": [ + 96, + 520, + 467, + 732 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 76, + 746, + 217, + 762 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Image Inpainting Methods", + "text_level": 1, + "bbox": [ + 76, + 771, + 316, + 787 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The task of image inpainting was and is being actively investigated by researchers during past decades. Classical approaches use diffusion processes [5, 6, 50, 8, 32] or exemplar-based techniques [17, 56, 20, 2, 4, 16, 31, 13] for coherent image restoration and completion. Although the classical methods greatly recover textures and preserve image structures, they lack of semantic understanding of the", + "bbox": [ + 75, + 794, + 467, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "image context. Hence learning-based approaches were developed and later improved.", + "bbox": [ + 498, + 90, + 888, + 119 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Early deep learning papers on image inpainting were trying to fill small missing regions by image-to-image discriminative models [57, 28, 44, 36]. Later, by using generative adversarial networks (GANs) [19], researchers were able to reach extra-high quality in image inpainting task [60, 42, 59, 33, 65, 53, 58, 66]. Some papers [36, 60, 42] additionally design special convolution layers to efficiently use the information in the known region of deep features. RFR [33] suggests a recurrent feature reasoning module which utilizes correlations between neighboring pixels to fill the missing pixels. With their contextual residual aggregation mechanism Yi et al. [59] enables ultra-high resolution inpainting (up to 8K). Several methods [65, 58, 66] benefit from a strong generative model StyleGAN-v2 [54] and make adoptions to image inpainting task. [65] introduces co-modulation blocks conditioning StyleGAN-v2 modulated architecture with the input image. SH-GAN [58] introduces spectral hint units to generate high-frequency details.", + "bbox": [ + 496, + 122, + 890, + 407 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "By benefiting from the Fourier analysis, LaMa [53] uses Fourier convolutions and greatly improves inpainting of repetitive patterns. ZITS [15] improves over LaMa by introducing a structure restoration mechanism with transformers. MAT [34] combines the strengths of convolutional and transformer-based models for large-hole inpainting.", + "bbox": [ + 496, + 409, + 890, + 500 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Recently, diffusion models [22, 52] were introduced and impacted the image inpainting task [46, 40, 48]. Palette [48] provides an image-conditioned diffusion model for image-to-image translation tasks, namely, colorization, inpainting/outpainting, and JPEG restoration. RePaint [40] adopts the unconditional pretrained Denoising Diffusion Probabilistic Model (DDPM) [22] for image inpainting task by guiding its backward process with inpainting masks. LDM [46] applies a diffusion process in its latent space which particularly allows conditioning on textual prompts, by so extending its image inpainting abilities to text guided completion.", + "bbox": [ + 496, + 501, + 890, + 681 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. Lightweight Generative Modeling", + "text_level": 1, + "bbox": [ + 500, + 695, + 795, + 710 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Although generative adversarial networks are able to create extremely high quality images often indistinguishable from reality with a naked eye, they require a tremendous amount of computations and memory consumption. For this purpose some methods [1, 10, 35, 9, 26, 45, 61, 62, 37] design lightweight generative models. [1] firstly applied the concept of knowledge distillation on GANs and showed incredible compression rates (e.g. 87:1 on CelebA [38]) while preserving the original quality. [10] utilizes the student discriminator in a triplet loss to enforce it benefit from teacher generated images also. In [35] the authors propose semantic preserving distillation loss for image-to", + "bbox": [ + 496, + 719, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "7336", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/7659809ef2490153e262f0eb228d0c0ce05731978583268bbcdbe07d4bc75dfa.jpg", + "image_caption": [ + "Figure 2. The overview of our method. The generator of MI-GAN consists of two branches: the main branch with a Unet like architecture and the painting branch. The main branch consists of a linear projection layer, depthwise separable convolutions, and bilinear resizing operations. The painting branch completes the missing region with layer-by-layer inpainting similar to the manual work of some experts. The training is conducted by using adversarial loss function and knowledge distillation. The discriminator is similar to the encoder of the main branch, having also residual connections and fully connected layers (more details can be found in supplementary material). As a teacher network in our experiments we take Co-Mod-GAN [65]. Please zoom in for better view." + ], + "image_footnote": [], + "bbox": [ + 76, + 88, + 883, + 415 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "image translation task to preserve the semantic relations between the teacher and the student features. TinyGAN [9] and TinyStarGAN-v2 [26] are distilling high-fidelity image generation networks BigGAN [7] and Stargan-v2 [12] respectively. [45] proposes a GAN compression method with a student discriminator-free online distillation scheme. Recently in [62] the authors introduce wavelet knowledge distillation to transfer the high-frequency detail generating information from the teacher generative model to the student. [37] proposes a content-aware compression paradigm, which leverages generated contents to guide the process of pruning and distillation.", + "bbox": [ + 75, + 530, + 472, + 710 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Method", + "text_level": 1, + "bbox": [ + 76, + 729, + 169, + 744 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Architecture", + "text_level": 1, + "bbox": [ + 76, + 755, + 210, + 768 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We introduce a simple baseline for mobile image inpainting which benefits from a combination of adversarial learning, model re-parametrization, and knowledge distillation. Formally, given an input image $I_{orig} \\in \\mathbb{R}^{H \\times W \\times 3}$ and a binary mask $M \\in \\{0,1\\}^{H \\times W}$ indicating the known region with 1-values and the missing region with 0-values. MI-GAN takes the concatenated input $In = [I_{orig} \\odot M, M] \\in \\mathbb{R}^{H \\times W \\times 4}$ and returns a completed image $I_c$ which is fi", + "bbox": [ + 75, + 779, + 468, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "nally composited with the original image by using the binary mask $M$ :", + "bbox": [ + 498, + 530, + 890, + 560 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nI _ {\\text {c o m p o s}} = I _ {\\text {o r i g}} \\odot M + I _ {c} \\odot (1 - M). \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 562, + 571, + 890, + 588 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The overview of our method is shown in Fig. 2.", + "bbox": [ + 498, + 598, + 815, + 613 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We design a generative adversarial network, the generator of which consists of two parts: a U-Net [47] like main branch utilizing depthwise separable convolution layers [51], and the painting branch imitating the inpainting process of experts. Being inspired by the architecture of StyleGAN [27], the concept of our painting branch is greatly aligned with the inpainting task. Indeed, similar to experts (artists), our painting branch paints the missing region iteratively layer-by-layer in the RGB-space starting from the overall structure and ending with the final result.", + "bbox": [ + 496, + 614, + 890, + 763 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The main branch architecture of MI-GAN starts with a convolution layer to project the 4-channel input space to a higher 128 dimension. Then a fully-convolutional encoder+decoder, consisting of depthwise separable convolutions and bilinear resizing operations, is applied resulting in a tensor with dimensionality $H \\times W \\times 128$ . All convolutional blocks are using the LeakyReLU activation. Inspired by StyleGAN, to generate high-frequency details, we also add a random noise component (with a learnable noise", + "bbox": [ + 496, + 763, + 892, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "7337", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/d8e69c3417c9470072454cf4fb2b47beb825397cbc42c352f4953b25a736ca64.jpg", + "image_caption": [ + "Figure 3. The structure of our depthwise separable convolution layers showing $(a)$ the model re-parametrization during training and $(b)$ the utilization of the fused weights during the inference. We apply bilinear resizing in the case when the depthwise separable convolution block changes its input resolution. In the case of both training and inference in each pointwise convolution layer a random noise with a trainable amplitude is applied." + ], + "image_footnote": [], + "bbox": [ + 96, + 85, + 893, + 361 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "amplitude) to the pointwise convolution layers of the decoder of the main branch (see Fig. 3). The painting branch takes the intermediate tensors from the main branch decoder and \"paints\" them to the RGB-space with projection convolutional layers, resulting in images $x_{i} \\in \\mathbb{R}_{\\frac{H}{2^{i}} \\times \\frac{W}{2^{i}} \\times 3}^{\\frac{H}{2^{i}} \\times \\frac{W}{2^{i}} \\times 3}$ for $i = 0,1,\\ldots,6$ . Then, the final image $I_{c} \\in \\mathbb{R}^{H \\times W \\times 3}$ is obtained by \"painting\" (adding) the images $x_{i}$ as layers on top of each other: $\\hat{x}_6 = x_6$ ,", + "bbox": [ + 75, + 445, + 472, + 570 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{c} \\hat {x} _ {i} = B i l i n e a r U p (\\hat {x} _ {i + 1}) + x _ {i}, i = 5, 4, \\dots , 0, \\\\ I _ {c} = \\hat {x} _ {0}, \\end{array} \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 104, + 575, + 468, + 611 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $BilinearUp$ is the bilinear upsampling operation with scaling factor equal to 2.", + "bbox": [ + 76, + 618, + 468, + 648 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "After the painting branch returns the inpainted image $I_{c}$ , we get the final result by using Eq. 1.", + "bbox": [ + 76, + 648, + 468, + 680 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Training", + "text_level": 1, + "bbox": [ + 76, + 686, + 181, + 703 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To train MI-GAN we use a combination of an adversarial and a knowledge distillation loss functions $\\mathcal{L}_{adv}$ and $\\mathcal{L}_{KD}$ respectively. For an adversarial training we borrow the discriminator architecture from StyleGAN [27] and replace convolutional layers with depthwise-separable convolutions. Also, similar to StyleGAN [27], we utilize a nonsaturating (with softplus non-linearity) loss function with $R_{1}$ -regularization [41] for discriminator training. For the generator MI-GAN the adversarial component of the loss function will accordingly be as follows:", + "bbox": [ + 76, + 710, + 468, + 861 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {a d v} = \\mathbb {E} _ {x, m \\sim P _ {c, m}} [ S o f t P l u s (- D _ {w} (G _ {\\theta} (x, m), m)) ], \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 89, + 869, + 468, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $P_{c,m}$ is the joint distribution of corrupted images (which should be inpainted) and the corresponding missing regions, $D_w$ is the discriminator, and $G_{\\theta}$ is the generator, i.e. our MI-GAN.", + "bbox": [ + 496, + 445, + 890, + 503 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "For a knowledge distillation we choose Co-Mod-GAN [65] as a teacher network for MI-GAN due to its strong generative ability inherited from StyleGAN-v2 [54]. Similar to us, inspired by StyleGAN, Co-Mod-GAN also has a painting branch. Hence we put a knowledge-distillation loss between the inpainted regions of intermediate results of the painting branches of Co-Mod-GAN and MI-GAN:", + "bbox": [ + 496, + 505, + 892, + 611 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {K D} = \\sum_ {i = 0} ^ {3} \\| \\left(x _ {i} - x _ {i} ^ {C}\\right) \\odot (1 - M _ {i}) \\|, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 565, + 618, + 890, + 659 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $x_{i}$ and $x_{i}^{C}$ are the intermediate results of painting branches of MI-GAN and Co-Mod-GAN respectively, and $M_{i} \\in \\{0,1\\}^{\\frac{H}{2^{i}} \\times \\frac{W}{2^{i}}}$ is obtained by resizing the binary mask $M$ to the size of $x_{i}$ (with the nearest neighbour interpolation). In Sec. 4.6 we discuss the effect of knowledge distillation loss.", + "bbox": [ + 496, + 667, + 890, + 758 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "So the final loss function for MI-GAN generator will be the weighted combination", + "bbox": [ + 496, + 761, + 890, + 791 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} = \\lambda_ {1} \\mathcal {L} _ {a d v} + \\lambda_ {2} \\mathcal {L} _ {K D}. \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 612, + 800, + 890, + 816 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In our experiments we take $\\lambda_1 = 1, \\lambda_2 = 2$ .", + "bbox": [ + 500, + 824, + 790, + 839 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Model Re-Parametrization", + "text_level": 1, + "bbox": [ + 500, + 847, + 741, + 861 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Re-parametrization is widely used for such tasks as compact model design [29], neural architecture search [11, 63]", + "bbox": [ + 498, + 869, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "7338", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "table", + "img_path": "images/945476dd65c53568bb26e505292dbecb6bcdbfda365c3533e28432c536c06540.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodFFHQPlaces2FLOPS (GFLOPS)Params (×106)
FID ↓LPIPS ↓FID ↓LPIPS ↓
LaMa32.710.25922.000.37832.0527.05
Co-Mod-GAN4.700.2579.320.39791.2179.17
SH-GAN4.330.2547.400.39291.2779.21
ZITS--16.780.356295.7278.49
MAT7.000.23114.380.394140.7459.78
LDM--13.400.3856,896.16387.25
HiFill--81.270.48818.142.72
MI-GAN (ours)4.990.25711.830.39411.195.95
", + "bbox": [ + 81, + 88, + 470, + 212 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Table 1. Quantitative comparison of our method with state-of-the-art approaches on 256 resolution images.", + "bbox": [ + 76, + 218, + 468, + 247 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "and pruning [14]. Inspired by recent work on online reparametrization [23], we adopt the technique to our architecture. We skip the linear scaling layer, instead we use weight normalizations described in [49]. We apply the reparametrization for all convolution layers in MI-GAN architecture.", + "bbox": [ + 75, + 270, + 468, + 359 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "For a convolutional layer $L_{i}$ during training we define $n$ kernels $\\omega_{i}^{1},\\omega_{i}^{2},\\ldots ,\\omega_{i}^{n}\\in \\mathbb{R}^{C_{O}\\times C_{I}\\times k\\times k}$ , where $C_O$ and $C_I$ are the numbers of output and input channels of $L_{i}$ respectively (for depthwise convolutions $C_I = 1$ regardless of input channel number of $L_{i}$ ), and $k$ is the kernel size. Then we initialize the kernels randomly from standard normal distribution, combine them via summation, and scale the result to have standard deviation equal to 1:", + "bbox": [ + 75, + 361, + 468, + 482 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\omega_ {i} = \\frac {1}{\\sqrt {n}} \\sum_ {j = 1} ^ {n} \\omega_ {i} ^ {j}. \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 210, + 493, + 468, + 532 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "This follows by a weight normalization operation $\\hat{\\omega}_i = \\frac{\\omega_i}{\\|\\omega_i\\|}$ . Finally $\\hat{\\omega}_i$ is being used as a convolutional (or depth-wise convolutional) kernel:", + "bbox": [ + 76, + 542, + 468, + 589 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nL _ {i} (x) = \\operatorname {C o n v} \\left(x, \\hat {\\omega} _ {i}\\right) + b _ {i}, \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 179, + 601, + 468, + 618 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $b_{i}$ is the convolutional bias initialized with zeros. During inference all additional parameters are fused and $\\hat{\\omega}_{i}$ is directly applied in Eq. 7.", + "bbox": [ + 75, + 627, + 467, + 672 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Our re-parametrization for depthwise-separable convolution blocks is shown in Fig. 3. In our experiments we take $n = 9$ to somehow \"compensate\" and make the network's capacity close to the capacity of its teacher network. The impact of the re-parametrization trick is discussed in Sec. 4.6.", + "bbox": [ + 75, + 672, + 468, + 762 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 777, + 209, + 792 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Implementation Details", + "text_level": 1, + "bbox": [ + 76, + 801, + 294, + 816 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Our experiments are conducted on Places2 [67] and FFHQ [27] datasets. Though our proposed model is fully convolutional, and can be used for inference on varying resolutions and aspect ratios, we create separate architectures for training on 256 and 512 resolution inputs. The purpose", + "bbox": [ + 75, + 824, + 468, + 902 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "of having separate architectures is to minimize the FLOPS and the memory usage for higher resolution inputs. The architectural details of our models can be found in the supplementary material.", + "bbox": [ + 496, + 90, + 890, + 151 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To train our models on Places2 dataset we use Places365-Standard subset, which contains $\\sim 1.8$ million images. All the metrics are calculated on Places2 validation set with 36,500 images. For 256 and 512 resolution models we train them for $\\sim 950,000$ and $\\sim 1,600,000$ iterations respectively. The training time for 256 and 512 resolution models was 23 days with 2 Nvidia Quadro-RTX 8000 GPUs and 30 days with 8 Nvidia A6000 GPUs respectively.", + "bbox": [ + 496, + 152, + 892, + 272 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We train the teacher Co-Mod-GAN model and our 256 resolution model on FFHQ by using randomly chosen 60,000 images, and evaluate all models on the rest 10,000 images. We train our model for $\\sim 800$ , 000 iterations for 10 days with 8 Nvidia A6000 GPUs.", + "bbox": [ + 496, + 273, + 890, + 348 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Adam optimizer is used with learning rate 0.001 and with $\\beta = (0,0.99)$ both for the generator and the discriminator. We fix batch size 32 for all experiments.", + "bbox": [ + 496, + 349, + 890, + 395 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Quantitative Comparison", + "text_level": 1, + "bbox": [ + 500, + 406, + 732, + 422 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Tables 1 and 2 show comparison of our method with state-of-the-arts Co-Mod-GAN [65], SH-GAN [58], LaMa [53], LDM [46], ZITS [15], MAT [34] and HiFill [59] on Places2 and FFHQ datasets respectively. All the models besides Co-Mod-GAN are taken from their official repositories or are kindly provided by the corresponding authors. For Co-Mod-GAN we re-implemented it in PyTorch [43], and trained and tested the replicated version. The FID [21] scores of the replicated Co-Mod-GAN match the FID scores in the original paper.", + "bbox": [ + 496, + 430, + 890, + 582 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "For the purpose of metric calculation we do the inference of all models in comparison using the free-form mask generation strategy as in Co-Mod-GAN [65]. The mask generation process combines multiple brush strokes and rectangles. The number of brush strokes is chosen randomly between 0 and 20. The widths of the brush strokes are chosen uniformly from the range (12, 40). Generated masks contain between 0 to 5 random rectangles up to the image size, and between 0 to 10 rectangles having maximum side fixed to the half of the image size. With this method of mask generation, masked area ratio varies between 0 and 1.", + "bbox": [ + 496, + 582, + 890, + 747 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We use Fréchet Inception Distance (FID) [21] as our primary metric. Also, we provide a comparison in terms of the perceptual metric LPIPS [64]. To show the computational complexity of the models we provide the number of floating point operations per second (FLOPS) and for the size of the models we report the number of model parameters.", + "bbox": [ + 496, + 750, + 890, + 839 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "As can be noticed from Table 1, on Places2 dataset our model outperforms LaMa, ZITS, MAT and HiFill in terms of FID and is comparable with LDM, while slightly underperforms Co-Mod-GAN and SH-GAN being on par with", + "bbox": [ + 496, + 839, + 890, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "7339", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/c04b20684672c0b18ab8b1aea6a3cc5a26bf874a914e89987a03c3bb428d31dc.jpg", + "image_caption": [ + "Figure 4. Qualitative results of our model and other state of the art approaches on 256 resolution Places 2 samples with free-form masks." + ], + "image_footnote": [], + "bbox": [ + 76, + 87, + 890, + 452 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/b056ed060704f5630f70acb7f226a9424ef4cc5286e6b174126c9aed0beca076.jpg", + "image_caption": [ + "Figure 5. Example results of our 512 resolution model and other state of the art approaches on 512 resolution Places2 test samples using free-form and user masks. Please zoom for a better view." + ], + "image_footnote": [], + "bbox": [ + 76, + 484, + 890, + 710 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "them in terms of the perceptual metric LPIPS. However MI-GAN is almost 8 times faster and 13 times lighter than Co-Mod-GAN and SH-GAN. This emphasizes a great generative ability of MI-GAN while being a compact model designed for mobile devices. Let us notice that LDM and MAT does not provide a model working on 256 resolution, so to inference on 256 resolution we resize images to 512, process them with 512 models and then resize back to 256. On FFHQ we can observe a similar picture, while our", + "bbox": [ + 75, + 763, + 472, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "method is even closer to Co-Mod-GAN and SH-GAN (i.e. has similar generative ability). For LaMa to inference on FFHQ dataset we have used the model trained on CelebA [38] dataset. LDM, ZITS and HiFill do not provide an inpainting model trained on faces.", + "bbox": [ + 496, + 763, + 890, + 839 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "For the image resolution 512 MI-GAN performs similarly to LaMa and ZITS in terms of FID and slightly underperforms Co-Mod-GAN, SH-GAN, LDM and MAT. Qualitative analysis performed in Sec. 4.3 shows that the small", + "bbox": [ + 496, + 839, + 892, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "7340", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/cc780c8b2cf23d7580435a4fff84b29874dabc46cc5086020dbd595fca6151c1.jpg", + "image_caption": [ + "(a)", + "(b)", + "Figure 6. (a) Total rating of each method based on our user study. (b) Visual examples from the user study. Please zoom-in for better view." + ], + "image_footnote": [], + "bbox": [ + 96, + 89, + 284, + 193 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/5a1e1e2328bdd27e51edeafe367640183c05e628e74950c5f720fb57a8e6acae.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 305, + 88, + 470, + 193 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/84083b3c2083c5a2cfd67a30082fd93b5c06c5337e37b7930acbc3ef55529f61.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 473, + 88, + 555, + 193 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/20bb641f1a621da3f8f620c09c2239b8b930033a14d4c3c48312acd67d59a7e0.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 555, + 88, + 638, + 193 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/156349b80c320a16d8723bf41eaa8326a74ab812c93affaba930e50a2da761da.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 638, + 88, + 720, + 193 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/0757840a27195a38ff778b0a0b8040fa6f677ccc9310a5e14fb6dbdc77a13066.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 722, + 88, + 803, + 193 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c9dc608fa77b43f570d1aa33405b0ba77b42e0053d3ad03eb72faadc0aa19a89.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 805, + 88, + 890, + 193 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/5bbd4da2ae55b1c72d7d5203136215fb692ed1672cc39b66aba0b75ae750da3f.jpg", + "image_caption": [ + "Figure 7. Qualitative results from our model and other approaches on FFHQ dataset samples. Please zoom for a better view." + ], + "image_footnote": [], + "bbox": [ + 81, + 234, + 467, + 448 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "difference in terms of FID has a small impact on visual results. Instead, our model is more than 7.5 times faster and 4.5 times lighter than the mentioned state-of-the-art approaches (see Table 2).", + "bbox": [ + 75, + 505, + 467, + 565 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Notice that even though HiFill has less number of parameters compared to our approach, MI-GAN is computationally more efficient and significantly outperforms HiFill quantitatively both on 256 and 512 resolutions. The reason that our model is computationally more efficient is that MI-GAN is a single-stage fully convolutional network consisting of depthwise-separable convolutions, whereas HiFill uses regular convolutions on higher resolution features and has a costly attention mechanism in its refinement network.", + "bbox": [ + 75, + 566, + 467, + 700 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "To show the effectiveness of our approach on different mask sizes, we provide FID comparisons with varying mask ratios in the appendix. Additionally, in order to further prove the robustness of our approach against other metrics, we also include a comparison in terms of PSNR, SSIM [55], P-IDS and U-IDS [65] metrics in the appendix.", + "bbox": [ + 75, + 700, + 467, + 792 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Qualitative Comparison", + "text_level": 1, + "bbox": [ + 76, + 801, + 297, + 816 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In this subsection we discuss the qualitative advantages of our model over some state-of-the-art approaches. As illustrated in Fig. 4 our model produces semantically meaningful content, even if the input mask is large. Our model has a strong generative capability, and the results are sharp,", + "bbox": [ + 75, + 825, + 467, + 900 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/163d3c0ee3197d8b1ad3c5c2a6130102949fd0170f01bf47454a43830cfaf7e1.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodFID ↓LPIPS ↓FLOPS (GFLOPS)Parameters (×106)
LaMa12.360.314128.0627.05
Co-Mod-GAN8.050.343121.0979.79
SH-GAN7.030.339121.1579.82
ZITS12.940.310666.9778.49
MAT8.670.339288.7861.56
LDM8.460.34227,581.56387.25
HiFill64.070.43872.122.72
MI-GAN (ours)10.000.34515.695.98
", + "bbox": [ + 504, + 234, + 890, + 388 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 2. Quantitative comparison of our method with state-of-the-art approaches on 512 resolution images.", + "bbox": [ + 500, + 393, + 890, + 422 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "while approaches like LaMa [53] and ZITS [15] produce blurry results on larger masks (see the 1st row of the figure as an example). Besides, as can be noticed from the qualitative comparison, on 256 resolution images our approach can perform better than the bigger and exceedingly computationally expensive model LDM [46].", + "bbox": [ + 496, + 450, + 890, + 541 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "On higher resolution images (see Fig. 5) our model still produces semantically meaningful results. Besides, our results don't have a color inconsistency issue unlike LDM, LaMa and ZITS results (see the 1st row of the figure as an exemple).", + "bbox": [ + 496, + 542, + 890, + 618 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We also conduct a qualitative comparison on face images (see Fig. 7). On face images our model's results are on par with Co-Mod-GAN and SH-GAN, while being better than LaMa and MAT.", + "bbox": [ + 496, + 619, + 890, + 679 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "More qualitative results can be found in the supplementary material.", + "bbox": [ + 496, + 681, + 890, + 710 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4. User Study", + "text_level": 1, + "bbox": [ + 500, + 724, + 620, + 739 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In addition to comparing our MI-GAN model with SOTA inpainting methods, we conduct a user study against 5 built-in commercial mobile image inpainting apps. For this, we select a diverse set of 20 real world photos from OpenImages [30] dataset with varying resolutions and, using each method in comparison, carefully mask and remove predetermined objects from each photo. Then, we ask 3 people to anonymously rate each of 5 results from 1 to 5 for each photo and sum the given ratings for each method (see Fig. 6.a). As can be seen from the diagram, our approach has a", + "bbox": [ + 496, + 750, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "7341", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/198db144133bcb46bcc2d8664b45a50332b7e2f76e835e46b6169bd86a19afae.jpg", + "table_caption": [], + "table_footnote": [ + "Table 3. The actual speed of our 256 model vs Co-Mod-GAN 256 model deployed on various mobile devices. The actual speed is measured in milliseconds, the means and the stds of the speed are presented for each mobile device. Some numbers are missing, since Co-Mod-GAN was providing an out of memory error." + ], + "table_body": "
Device Name256-resolution
MI-GAN speed (ms, mean/std)Co-Mod-GAN speed (ms, mean/std)
iPhone71030.25 / 13.374475.33 / 39.55
iPhoneX630.80 / 12.212746.00 / 28.84
iPad mini (5th gen)552.40 / 8.102686.17 / 41.41
iPhone14-pro-max296.00 / 1.351374.40 / 84.78
Galaxy Tab S7+686.17 / 12.36- / -
Samsung Galaxy S81476.40 / 5.98- / -
vivo Y122918.08 / 33.47- / -
", + "bbox": [ + 81, + 88, + 472, + 238 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "clear advantage over other methods. Fig. 6.b shows qualitative samples from user study, where our result has obvious advantage over commercial mobile apps. We include more results in the supplementary material.", + "bbox": [ + 75, + 344, + 470, + 405 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.5. Actual Speed on Mobile Devices", + "text_level": 1, + "bbox": [ + 76, + 421, + 359, + 438 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Besides calculating FLOPS we also measure actual speed of our method on real mobile devices and compare MI-GAN with Co-Mod-GAN. As can be noticed from Table 3 on 256 resolution inputs our method is more than 4 times faster on average than Co-Mod-GAN, which allows MI-GAN to be used in real-world applications on mobile devices.", + "bbox": [ + 75, + 446, + 468, + 551 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "All models in Table 3 are using CPUs of mobile devices and are deployed by using the neural network framework ONNX [3]. Nothing special was conducted to optimize the speed or memory usage of MI-GAN on ONNX, so we believe MI-GAN can be further optimized in terms of speed or memory consumption (particularly running it on GPUs of mobile devices). The actual running times on 512 resolution images can be found in the supplementary material.", + "bbox": [ + 75, + 555, + 470, + 676 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.6. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 693, + 230, + 709 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this subsection we show the impact of our re-parametrization trick and knowledge distillation loss function for MI-GAN 256 resolution model. Both are designed to close the generative performance gap between MI-GAN and a larger inpainting network. Table 4 shows the quantitative effect of both. Fig. 8 shows that by adding re-parametrization trick we increase the semantic understanding of the model to generate more meaningful results. Further, the knowledge distillation adds more generative ability. Although both modifications has positive impact, one can notice that re-parametrization trick improves the method drastically (see also Fig. 8).", + "bbox": [ + 75, + 719, + 470, + 902 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/53e89b24dcc61229749aa69e4bbea18339b89e682b2e9a0939fb52e2b9b87d36.jpg", + "table_caption": [], + "table_footnote": [ + "Table 4. The effect of model re-parametrization and knowledge distillation on MI-GAN 256 resolution model. As can be noticed both have positive impact in terms of both metrics FID and LPIPS." + ], + "table_body": "
MethodFID ↓LPIPS ↓
Baseline14.940.407
Baseline + Re-Param12.220.400
MI-GAN: Baseline + Re-Param + KD11.830.39
", + "bbox": [ + 513, + 88, + 877, + 162 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/e34987006d4348a46ad2d4666217a9882257d3677d8ec9cc95a747e9368e7b83.jpg", + "image_caption": [ + "Figure 8. Visual results of ablation study on model reparametrization and knowledge distillation." + ], + "image_footnote": [], + "bbox": [ + 501, + 239, + 893, + 479 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Limitations and Societal Impact", + "text_level": 1, + "bbox": [ + 500, + 554, + 794, + 571 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Although our method has good generation abilities producing visually plausible results, similar to other state-of-the-art approaches it sometimes meets difficulties when reconstructing complex 3D structures. We hypothesize this can be later improved by guiding the network with more information about the 3D structure of the objects in images. For visual examples of MI-GAN's failure cases please see our supplementary material.", + "bbox": [ + 496, + 589, + 890, + 710 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Our work aims to make the creative image editing easier and accessible for everyone with their mobile devices. Similar to other deep learning based image editing approaches our method may have both positive and negative societal impact depending on its application. As a positive impact MI-GAN can help the users to restore old photos or remove unpleasant objects from their photos making them more aesthetic. On the negative side it can be used to misrepresent the reality by removing important facts from the images. We strongly believe and hope that our work will give more positive value to creative editing users than its potential negative societal impact.", + "bbox": [ + 496, + 719, + 892, + 901 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "7342", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 90, + 194, + 104 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this paper we introduce MI-GAN, the first generative mobile image inpainting network. By using depthwise separable convolutions, model re-parametrization, and knowledge distillation, MI-GAN is able to produce high-quality results while having a low computational cost and a small number of parameters. Qualitative and quantitative comparisons show that MI-GAN is comparable or sometimes outperforms the current state-of-the-art approaches while being a way faster and smaller.", + "bbox": [ + 75, + 114, + 472, + 251 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 265, + 174, + 280 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Angeline Aguinaldo, Ping-Yeh Chiang, Alex Gain, Ameya Patil, Kolten Pearson, and Soheil Feizi. Compressing gans using knowledge distillation. arXiv preprint arXiv:1902.00159, 2019. 2", + "[2] Michael Ashikhmin. Synthesizing natural textures. In Proceedings of the 2001 symposium on Interactive 3D graphics, pages 217-226, 2001. 2", + "[3] Junjie Bai, Fang Lu, Ke Zhang, et al. Onnx: Open neural network exchange. https://github.com/onnx/onnx, 2019.8", + "[4] Connelly Barnes, Eli Shechtman, Adam Finkelstein, and Dan B Goldman. Patchmatch: A randomized correspondence algorithm for structural image editing. ACM Trans. Graph., 28(3):24, 2009. 2", + "[5] Marcelo Bertalmio, Guillermo Sapiro, Vincent Caseles, and Coloma Ballester. Image inpainting. In Proceedings of the 27th annual conference on Computer graphics and interactive techniques, pages 417-424, 2000. 2", + "[6] Marcelo Bertalmio, Luminita Vese, Guillermo Sapiro, and Stanley Osher. Simultaneous structure and texture image inpainting. IEEE transactions on image processing, 12(8):882-889, 2003. 2", + "[7] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. arXiv preprint arXiv:1809.11096, 2018.3", + "[8] Tony F Chan and Jianhong Shen. Nontexture inpainting by curvature-driven diffusions. Journal of visual communication and image representation, 12(4):436-449, 2001. 2", + "[9] Ting-Yun Chang and Chi-Jen Lu. Tinygan: Distilling big-gan for conditional image generation. In Proceedings of the Asian Conference on Computer Vision, 2020. 2, 3", + "[10] Hanting Chen, Yunhe Wang, Han Shu, Changyuan Wen, Chunjing Xu, Boxin Shi, Chao Xu, and Chang Xu. Distilling portable generative adversarial networks for image translation. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 3585-3592, 2020. 2", + "[11] Shoufa Chen, Yunpeng Chen, Shuicheng Yan, and Jiashi Feng. Efficient differentiable neural architecture search with meta kernels. ArXiv, abs/1912.04749, 2019. 4", + "[12] Yunjey Choi, Youngjung Uh, Jaejun Yoo, and Jung-Woo Ha. Stargan v2: Diverse image synthesis for multiple domains. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 8188-8197, 2020. 3" + ], + "bbox": [ + 78, + 289, + 468, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[13] Antonio Criminisi, Patrick Pérez, and Kentaro Toyama. Region filling and object removal by exemplar-based image inpainting. IEEE Transactions on image processing, 13(9):1200-1212, 2004. 2", + "[14] Xiaohan Ding, Tianxiang Hao, Jianchao Tan, Ji Liu, Jungong Han, Yuchen Guo, and Guiguang Ding. Resrep: Lossless cnn pruning via decoupling remembering and forgetting. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4510-4520, 2021. 5", + "[15] Qiaole Dong, Chenjie Cao, and Yanwei Fu. Incremental transformer structure enhanced image inpainting with masking positional encoding. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11358-11368, 2022. 2, 5, 7", + "[16] Alexei A Efros and William T Freeman. Image quilting for texture synthesis and transfer. In Proceedings of the 28th annual conference on Computer graphics and interactive techniques, pages 341-346, 2001. 2", + "[17] Alexei A Efros and Thomas K Leung. Texture synthesis by non-parametric sampling. In Proceedings of the seventh IEEE international conference on computer vision, volume 2, pages 1033-1038. IEEE, 1999. 2", + "[18] ADVA Soft GmbH. Touchretouch. 1", + "[19] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. Communications of the ACM, 63(11):139–144, 2020. 2", + "[20] Paul Harrison. A non-hierarchical procedure for re-synthesis of complex textures. 2001. 2", + "[21] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in neural information processing systems, 30, 2017. 5", + "[22] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Advances in Neural Information Processing Systems, 33:6840-6851, 2020. 2", + "[23] Mu Hu, Junyi Feng, Jiashen Hua, Baisheng Lai, Jianqiang Huang, Xiaojin Gong, and Xian-Sheng Hua. Online convolutional re-parameterization. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 568-577, 2022. 5", + "[24] Adobe Inc. Photoshop express photo editor. 1", + "[25] Picsart Inc. Picsart photo editor & video. 1", + "[26] Paras Kapoor and Tien D. Bui. Tinystargan v2: Distilling stargan v2 for efficient diverse image synthesis for multiple domains. In BMVC, 2021. 2, 3", + "[27] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In 2019 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4396-4405, 2019. 1, 3, 4, 5", + "[28] Rolf Kohler, Christian Schuler, Bernhard Schölkopf, and Stefan Harmeling. Mask-specific inpainting with deep neural networks. In German conference on pattern recognition, pages 523-534. Springer, 2014. 2" + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "7343", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[29] Alexander Kolesnikov, Alexey Dosovitskiy, Dirk Weissenborn, Georg Heigold, Jakob Uszkoreit, Lucas Beyer, Matthias Minderer, Mostafa Dehghani, Neil Houlsby, Sylvain Gelly, Thomas Unterthiner, and Xiaohua Zhai. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations (ICLR), 2021. 4", + "[30] Alina Kuznetsova, Hassan Rom, Neil Alldrin, Jasper Uijlings, Ivan Krasin, Jordi Pont-Tuset, Shahab Kamali, Stefan Popov, Matteo Malloci, Alexander Kolesnikov, Tom Duerig, and Vittorio Ferrari. The open images dataset v4: Unified image classification, object detection, and visual relationship detection at scale. IJCV, 2020. 7", + "[31] Vivek Kwatra, Arno Schödl, Irfan Essa, Greg Turk, and Aaron Bobick. Graphcut textures: Image and video synthesis using graph cuts. Acm transactions on graphics (tog), 22(3):277-286, 2003. 2", + "[32] Anat Levin, Assaf Zomet, and Yair Weiss. Learning how to inpaint from global image statistics. In ICCV, volume 1, pages 305-312, 2003. 2", + "[33] Jingyuan Li, Ning Wang, Lefei Zhang, Bo Du, and Dacheng Tao. Recurrent feature reasoning for image inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7760-7768, 2020. 2", + "[34] Wenbo Li, Zhe Lin, Kun Zhou, Lu Qi, Yi Wang, and Jiaya Jia. Mat: Mask-aware transformer for large hole image inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10758-10768, 2022. 2, 5", + "[35] Zeqi Li, Ruowei Jiang, and Parham Aarabi. Semantic relation preserving knowledge distillation for image-to-image translation. In European conference on computer vision, pages 648-663. Springer, 2020. 2", + "[36] Guilin Liu, Fitsum A Reda, Kevin J Shih, Ting-Chun Wang, Andrew Tao, and Bryan Catanzaro. Image inpainting for irregular holes using partial convolutions. In Proceedings of the European conference on computer vision (ECCV), pages 85-100, 2018. 2", + "[37] Yuchen Liu, Zhixin Shu, Yijun Li, Zhe Lin, Federico Peruzzi, and Sun-Yuan Kung. Content-aware gan compression. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12156-12166, 2021. 2, 3", + "[38] Ziwei Liu, Ping Luo, Xiaogang Wang, and Xiaou Tang. Deep learning face attributes in the wild. In Proceedings of International Conference on Computer Vision (ICCV), December 2015. 2, 6", + "[39] Google LLC. Snapseed. 1", + "[40] Andreas Lugmayr, Martin Danelljan, Andres Romero, Fisher Yu, Radu Timofte, and Luc Van Gool. Repaint: Inpainting using denoising diffusion probabilistic models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11461-11471, 2022. 2", + "[41] Lars Mescheder, Andreas Geiger, and Sebastian Nowozin. Which training methods for gans do actually converge? In International conference on machine learning, pages 3481-3490. PMLR, 2018. 4" + ], + "bbox": [ + 78, + 90, + 470, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[42] Shant Navasardyan and Marianna Ohanyan. The family of onion convolutions for image inpainting. International Journal of Computer Vision, pages 1-30, 2022. 2", + "[43] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, Luca Antiga, Alban Desmaison, Andreas Kopf, Edward Yang, Zachary DeVito, Martin Raison, Alykhan Tejani, Sasank Chilamkurthy, Benoit Steiner, Lu Fang, Junjie Bai, and Soumith Chintala. Pytorch: An imperative style, high-performance deep learning library. In Advances in Neural Information Processing Systems 32, pages 8024-8035. Curran Associates, Inc., 2019. 5", + "[44] Jimmy S Ren, Li Xu, Qiong Yan, and Wenxiu Sun. Shepard convolutional neural networks. Advances in neural information processing systems, 28, 2015. 2", + "[45] Yuxi Ren, Jie Wu, Xuefeng Xiao, and Jianchao Yang. Online multi-granularity distillation for gan compression. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6793-6803, 2021. 2, 3", + "[46] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684-10695, 2022. 2, 5, 7", + "[47] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image computing and computer-assisted intervention, pages 234-241. Springer, 2015. 3", + "[48] Chitwan Sahara, William Chan, Huiwen Chang, Chris Lee, Jonathan Ho, Tim Salimans, David Fleet, and Mohammad Norouzi. Palette: Image-to-image diffusion models. In ACM SIGGRAPH 2022 Conference Proceedings, pages 1-10, 2022. 2", + "[49] Tim Salimans and Durk P Kingma. Weight normalization: A simple reparameterization to accelerate training of deep neural networks. Advances in neural information processing systems, 29, 2016. 5", + "[50] Jianhong Shen and Tony F Chan. Mathematical models for local nontexture inpaintings. SIAM Journal on Applied Mathematics, 62(3):1019-1043, 2002. 2", + "[51] L Sifre and S Mallat. Rigid-motion scattering for image classification [phd thesis]. Ecole Polytechnique, 2014. 3", + "[52] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. arXiv preprint arXiv:2010.02502, 2020. 2", + "[53] Roman Suvorov, Elizaveta Logacheva, Anton Mashikhin, Anastasia Remizova, Armenii Ashukha, Aleksei Silvestrov, Naejin Kong, Harshith Goka, Kiwoong Park, and Victor Lempitsky. Resolution-robust large mask inpainting with fourier convolutions. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 2149–2159, 2022. 2, 5, 7", + "[54] Yuri Viazovetskyi, Vladimir Ivashkin, and Evgeny Kashin. Stylegan2 distillation for feed-forward image manipulation. In European conference on computer vision, pages 170-186. Springer, 2020. 2, 4" + ], + "bbox": [ + 501, + 92, + 893, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "7344", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[55] Z. Wang, E.P. Simoncelli, and A.C. Bovik. Multiscale structural similarity for image quality assessment. In The Thirty-Seventh Asilomar Conference on Signals, Systems & Computers, 2003, volume 2, pages 1398-1402 Vol.2, 2003. 7", + "[56] Li-Yi Wei and Marc Levoy. Fast texture synthesis using tree-structured vector quantization. In Proceedings of the 27th annual conference on Computer graphics and interactive techniques, pages 479–488, 2000. 2", + "[57] Junyuan Xie, Linli Xu, and Enhong Chen. Image denoising and inpainting with deep neural networks. Advances in neural information processing systems, 25, 2012. 2", + "[58] Xingqian Xu, Shant Navasardyan, Vahram Tadevosyan, Andranik Sargsyan, Yadong Mu, and Humphrey Shi. Image completion with heterogeneously filtered spectral hints. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, 2023. 2, 5", + "[59] Zili Yi, Qiang Tang, Shekoofeh Azizi, Daesik Jang, and Zhan Xu. Contextual residual aggregation for ultra high-resolution image inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7508-7517, 2020. 2, 5", + "[60] Jiahui Yu, Zhe Lin, Jamei Yang, Xiaohui Shen, Xin Lu, and Thomas S Huang. Free-form image inpainting with gated convolution. In Proceedings of the IEEE/CVF international conference on computer vision, pages 4471-4480, 2019. 2", + "[61] Linfeng Zhang, Xin Chen, Runpei Dong, and Kaisheng Ma. Region-aware knowledge distillation for efficient image-to-image translation. arXiv preprint arXiv:2205.12451, 2022. 2", + "[62] Linfeng Zhang, Xin Chen, Xiaobing Tu, Pengfei Wan, Ning Xu, and Kaisheng Ma. Wavelet knowledge distillation: Towards efficient image-to-image translation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12464-12474, 2022. 2, 3", + "[63] Mingyang Zhang, Xinyi Yu, Jingtao Rong, Linlin Ou, and Feng Gao. Repnas: Searching for efficient re-parameterizing blocks. arXiv preprint arXiv:2109.03508, 2021. 4", + "[64] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 586-595, 2018. 5", + "[65] Shengyu Zhao, Jonathan Cui, Yilun Sheng, Yue Dong, Xiao Liang, Eric I Chang, and Yan Xu. Large scale image completion via co-modulated generative adversarial networks. In International Conference on Learning Representations (ICLR), 2021. 2, 3, 4, 5, 7", + "[66] Haitian Zheng, Zhe Lin, Jingwan Lu, Scott Cohen, Eli Shechtman, Connelly Barnes, Jianming Zhang, Ning Xu, Sohrab Amirghodsi, and Jiebo Luo. Cm-gan: Image inpainting with cascaded modulation gan and object-aware training. arXiv preprint arXiv:2203.11947, 2022. 2", + "[67] Bolei Zhou, Agata Lapedriza, Aditya Khosla, Aude Oliva, and Antonio Torralba. Places: A 10 million image database for scene recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 40(6):1452-1464, 2018. 1, 5" + ], + "bbox": [ + 78, + 90, + 468, + 892 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "7345", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/af22c1bd-1590-4032-ac12-a1b776021514_model.json b/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/af22c1bd-1590-4032-ac12-a1b776021514_model.json new file mode 100644 index 0000000000000000000000000000000000000000..478c568d0adb3a59f8d95f3392d3ca35c1c723c5 --- /dev/null +++ b/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/af22c1bd-1590-4032-ac12-a1b776021514_model.json @@ -0,0 +1,2444 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.138, + 0.131, + 0.834, + 0.154 + ], + "angle": 0, + "content": "MI-GAN: A Simple Baseline for Image Inpainting on Mobile Devices" + }, + { + "type": "text", + "bbox": [ + 0.183, + 0.18, + 0.787, + 0.2 + ], + "angle": 0, + "content": "Andranik Sargsyan1, Shant Navasardyan1, Xingqian Xu1,2, Humphrey Shi1,2" + }, + { + "type": "text", + "bbox": [ + 0.26, + 0.201, + 0.71, + 0.217 + ], + "angle": 0, + "content": "1Picsart AI Research (PAIR), 2SHI Labs @ Georgia Tech, Oregon & UIUC" + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.269, + 0.24, + 0.353 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.353, + 0.24, + 0.437 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.241, + 0.269, + 0.431, + 0.353 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.241, + 0.353, + 0.431, + 0.437 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.433, + 0.269, + 0.541, + 0.353 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.433, + 0.353, + 0.541, + 0.437 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.545, + 0.269, + 0.891, + 0.437 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.075, + 0.442, + 0.894, + 0.512 + ], + "angle": 0, + "content": "Figure 1. The proposed approach can produce plausible results both on complex scene images as well as on face images. The scene image inputs are taken from the Places 2 [67] dataset and the face image input is from FFHQ [27] dataset. The bubble chart on the right shows the advantage of our network over state-of-the-art approaches. The size of the bubble signifies the relative number of parameters of each approach and the number inside of the bubble shows the absolute number of model parameters. Our approach achieves a low FID, while being one order of magnitude smaller and faster than recent SOTA approaches." + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.53, + 0.314, + 0.545 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.571, + 0.474, + 0.903 + ], + "angle": 0, + "content": "In recent years, many deep learning based image inpainting methods have been developed by the research community. Some of those methods have shown impressive image completion abilities. Yet, to the best of our knowledge, there is no image inpainting model designed to run on mobile devices. In this paper we present a simple image inpainting baseline, Mobile Inpainting GAN (MI-GAN), which is approximately one order of magnitude computationally cheaper and smaller than existing state-of-the-art inpainting models, and can be efficiently deployed on mobile devices. Excessive quantitative and qualitative evaluations show that MI-GAN performs comparable or, in some cases, better than recent state-of-the-art approaches. Moreover, we perform a user study comparing MI-GAN results with results from several commercial mobile inpainting applications, which clearly shows the advantage of MI-GAN in comparison to existing apps. With the purpose of high quality and efficient inpainting, we utilize an effective combination of adversarial training, model reparametrization, and knowledge distillation. Our models and code are publicly available at https://github.com/Picsart-AI-Research/MI-GAN." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.574, + 0.631, + 0.59 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.599, + 0.892, + 0.674 + ], + "angle": 0, + "content": "The task of image inpainting is to complete the missing regions in images in a realistic and visually plausible way. Image inpainting algorithms have found their applications in such problems as image restoration, removal of unwanted objects, etc." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.676, + 0.893, + 0.885 + ], + "angle": 0, + "content": "Nowadays, in the era of fast evolving gadgets, particularly smartphones, image/video editing applications are growing furiously. The usage of mobile devices for making creative visual content by professionals as well as by consumers shows a great increasing tendency. A lot of mobile applications such as Photoshop Express [24], Picsart [25], Snapseed [39], TouchRetouch [18] empower the users to create awesome content utilizing AI-powered tools. One of the most popular such tools, object remover, allows its users to remove unwanted objects (e.g. watermarks, lines, people or random objects in the background, etc.) from their photos. So millions of users every day benefit from image inpainting technologies integrated in various mobile applications." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.887, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Current AI-based state-of-the-art inpainting algorithms" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "7335" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.198 + ], + "angle": 0, + "content": "such as Co-Mod-GAN [65], SH-GAN [58], LaMa [53], or LDM [46] include an inference of a heavyweight neural network, which is often not feasible to do on low-end mobile devices (see Tables 1, 2). Therefore the processing is being done on server-side resulting in dependency on Internet connection, speed, traffic and server usage costs for image editing companies." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.198, + 0.47, + 0.273 + ], + "angle": 0, + "content": "To address this problem we propose a simple baseline for high-quality mobile image inpainting which is an order of magnitude lighter and computationally more efficient than current state-of-the-art neural networks while showing similar or sometimes even better performance (see Fig. 1)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.273, + 0.468, + 0.451 + ], + "angle": 0, + "content": "Motivated by the generative nature of the image completion problem we design MI-GAN, Mobile Inpainting Generative Adversarial Network, which benefits from a hybrid system consisting of adversarial training, model reparametrization, and knowledge distillation. Thanks to adversarial nature of the MI-GAN training, image completion results appear to be visually plausible without producing blurry regions and pattern-like artifacts. Model reparametrization further increases the output quality at no cost of efficiency. Finally, knowledge distillation by a stronger network also improves the generative ability of MI-GAN." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.455, + 0.468, + 0.499 + ], + "angle": 0, + "content": "Due to excessive evaluations MI-GAN shows great performance in terms of both quantitative and qualitative comparison with existing state-of-the-art methods." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.5, + 0.41, + 0.513 + ], + "angle": 0, + "content": "To summarize, our contributions are three-fold." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.521, + 0.468, + 0.552 + ], + "angle": 0, + "content": "- We propose MI-GAN, to the best of our knowledge the first mobile generative image inpainting network." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.561, + 0.468, + 0.621 + ], + "angle": 0, + "content": "- We develop a customized knowledge distillation method that is suitable for our model and problem, as well as we implement a model re-parametrization strategy which enhances the quality of results." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.63, + 0.468, + 0.733 + ], + "angle": 0, + "content": "- While being computationally more efficient and lighter than the existing state-of-the-art image completion approaches, MI-GAN produces similar or even better image inpainting results. Furthermore, in comparison to existing commercial mobile inpainting applications, MI-GAN results are generally rated higher by human evaluators." + }, + { + "type": "list", + "bbox": [ + 0.097, + 0.521, + 0.468, + 0.733 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.747, + 0.218, + 0.763 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.772, + 0.318, + 0.789 + ], + "angle": 0, + "content": "2.1. Image Inpainting Methods" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.468, + 0.901 + ], + "angle": 0, + "content": "The task of image inpainting was and is being actively investigated by researchers during past decades. Classical approaches use diffusion processes [5, 6, 50, 8, 32] or exemplar-based techniques [17, 56, 20, 2, 4, 16, 31, 13] for coherent image restoration and completion. Although the classical methods greatly recover textures and preserve image structures, they lack of semantic understanding of the" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.89, + 0.121 + ], + "angle": 0, + "content": "image context. Hence learning-based approaches were developed and later improved." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.123, + 0.892, + 0.408 + ], + "angle": 0, + "content": "Early deep learning papers on image inpainting were trying to fill small missing regions by image-to-image discriminative models [57, 28, 44, 36]. Later, by using generative adversarial networks (GANs) [19], researchers were able to reach extra-high quality in image inpainting task [60, 42, 59, 33, 65, 53, 58, 66]. Some papers [36, 60, 42] additionally design special convolution layers to efficiently use the information in the known region of deep features. RFR [33] suggests a recurrent feature reasoning module which utilizes correlations between neighboring pixels to fill the missing pixels. With their contextual residual aggregation mechanism Yi et al. [59] enables ultra-high resolution inpainting (up to 8K). Several methods [65, 58, 66] benefit from a strong generative model StyleGAN-v2 [54] and make adoptions to image inpainting task. [65] introduces co-modulation blocks conditioning StyleGAN-v2 modulated architecture with the input image. SH-GAN [58] introduces spectral hint units to generate high-frequency details." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.41, + 0.892, + 0.501 + ], + "angle": 0, + "content": "By benefiting from the Fourier analysis, LaMa [53] uses Fourier convolutions and greatly improves inpainting of repetitive patterns. ZITS [15] improves over LaMa by introducing a structure restoration mechanism with transformers. MAT [34] combines the strengths of convolutional and transformer-based models for large-hole inpainting." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.502, + 0.892, + 0.683 + ], + "angle": 0, + "content": "Recently, diffusion models [22, 52] were introduced and impacted the image inpainting task [46, 40, 48]. Palette [48] provides an image-conditioned diffusion model for image-to-image translation tasks, namely, colorization, inpainting/outpainting, and JPEG restoration. RePaint [40] adopts the unconditional pretrained Denoising Diffusion Probabilistic Model (DDPM) [22] for image inpainting task by guiding its backward process with inpainting masks. LDM [46] applies a diffusion process in its latent space which particularly allows conditioning on textual prompts, by so extending its image inpainting abilities to text guided completion." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.696, + 0.796, + 0.712 + ], + "angle": 0, + "content": "2.2. Lightweight Generative Modeling" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Although generative adversarial networks are able to create extremely high quality images often indistinguishable from reality with a naked eye, they require a tremendous amount of computations and memory consumption. For this purpose some methods [1, 10, 35, 9, 26, 45, 61, 62, 37] design lightweight generative models. [1] firstly applied the concept of knowledge distillation on GANs and showed incredible compression rates (e.g. 87:1 on CelebA [38]) while preserving the original quality. [10] utilizes the student discriminator in a triplet loss to enforce it benefit from teacher generated images also. In [35] the authors propose semantic preserving distillation loss for image-to" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "7336" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.078, + 0.089, + 0.885, + 0.416 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.422, + 0.896, + 0.507 + ], + "angle": 0, + "content": "Figure 2. The overview of our method. The generator of MI-GAN consists of two branches: the main branch with a Unet like architecture and the painting branch. The main branch consists of a linear projection layer, depthwise separable convolutions, and bilinear resizing operations. The painting branch completes the missing region with layer-by-layer inpainting similar to the manual work of some experts. The training is conducted by using adversarial loss function and knowledge distillation. The discriminator is similar to the encoder of the main branch, having also residual connections and fully connected layers (more details can be found in supplementary material). As a teacher network in our experiments we take Co-Mod-GAN [65]. Please zoom in for better view." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.531, + 0.473, + 0.712 + ], + "angle": 0, + "content": "image translation task to preserve the semantic relations between the teacher and the student features. TinyGAN [9] and TinyStarGAN-v2 [26] are distilling high-fidelity image generation networks BigGAN [7] and Stargan-v2 [12] respectively. [45] proposes a GAN compression method with a student discriminator-free online distillation scheme. Recently in [62] the authors introduce wavelet knowledge distillation to transfer the high-frequency detail generating information from the teacher generative model to the student. [37] proposes a content-aware compression paradigm, which leverages generated contents to guide the process of pruning and distillation." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.73, + 0.17, + 0.745 + ], + "angle": 0, + "content": "3. Method" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.756, + 0.212, + 0.77 + ], + "angle": 0, + "content": "3.1. Architecture" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.47, + 0.903 + ], + "angle": 0, + "content": "We introduce a simple baseline for mobile image inpainting which benefits from a combination of adversarial learning, model re-parametrization, and knowledge distillation. Formally, given an input image \\( I_{orig} \\in \\mathbb{R}^{H \\times W \\times 3} \\) and a binary mask \\( M \\in \\{0,1\\}^{H \\times W} \\) indicating the known region with 1-values and the missing region with 0-values. MI-GAN takes the concatenated input \\( In = [I_{orig} \\odot M, M] \\in \\mathbb{R}^{H \\times W \\times 4} \\) and returns a completed image \\( I_c \\) which is fi" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.531, + 0.892, + 0.561 + ], + "angle": 0, + "content": "nally composited with the original image by using the binary mask \\(M\\):" + }, + { + "type": "equation", + "bbox": [ + 0.563, + 0.572, + 0.892, + 0.589 + ], + "angle": 0, + "content": "\\[\nI _ {\\text {c o m p o s}} = I _ {\\text {o r i g}} \\odot M + I _ {c} \\odot (1 - M). \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.599, + 0.816, + 0.614 + ], + "angle": 0, + "content": "The overview of our method is shown in Fig. 2." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.615, + 0.892, + 0.765 + ], + "angle": 0, + "content": "We design a generative adversarial network, the generator of which consists of two parts: a U-Net [47] like main branch utilizing depthwise separable convolution layers [51], and the painting branch imitating the inpainting process of experts. Being inspired by the architecture of StyleGAN [27], the concept of our painting branch is greatly aligned with the inpainting task. Indeed, similar to experts (artists), our painting branch paints the missing region iteratively layer-by-layer in the RGB-space starting from the overall structure and ending with the final result." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.893, + 0.901 + ], + "angle": 0, + "content": "The main branch architecture of MI-GAN starts with a convolution layer to project the 4-channel input space to a higher 128 dimension. Then a fully-convolutional encoder+decoder, consisting of depthwise separable convolutions and bilinear resizing operations, is applied resulting in a tensor with dimensionality \\( H \\times W \\times 128 \\). All convolutional blocks are using the LeakyReLU activation. Inspired by StyleGAN, to generate high-frequency details, we also add a random noise component (with a learnable noise" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "7337" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.098, + 0.087, + 0.895, + 0.362 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.365, + 0.893, + 0.422 + ], + "angle": 0, + "content": "Figure 3. The structure of our depthwise separable convolution layers showing \\((a)\\) the model re-parametrization during training and \\((b)\\) the utilization of the fused weights during the inference. We apply bilinear resizing in the case when the depthwise separable convolution block changes its input resolution. In the case of both training and inference in each pointwise convolution layer a random noise with a trainable amplitude is applied." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.446, + 0.473, + 0.571 + ], + "angle": 0, + "content": "amplitude) to the pointwise convolution layers of the decoder of the main branch (see Fig. 3). The painting branch takes the intermediate tensors from the main branch decoder and \"paints\" them to the RGB-space with projection convolutional layers, resulting in images \\( x_{i} \\in \\mathbb{R}_{\\frac{H}{2^{i}} \\times \\frac{W}{2^{i}} \\times 3}^{\\frac{H}{2^{i}} \\times \\frac{W}{2^{i}} \\times 3} \\) for \\( i = 0,1,\\ldots,6 \\). Then, the final image \\( I_{c} \\in \\mathbb{R}^{H \\times W \\times 3} \\) is obtained by \"painting\" (adding) the images \\( x_{i} \\) as layers on top of each other: \\( \\hat{x}_6 = x_6 \\)," + }, + { + "type": "equation", + "bbox": [ + 0.105, + 0.577, + 0.469, + 0.612 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{c} \\hat {x} _ {i} = B i l i n e a r U p (\\hat {x} _ {i + 1}) + x _ {i}, i = 5, 4, \\dots , 0, \\\\ I _ {c} = \\hat {x} _ {0}, \\end{array} \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.619, + 0.47, + 0.649 + ], + "angle": 0, + "content": "where \\(BilinearUp\\) is the bilinear upsampling operation with scaling factor equal to 2." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.65, + 0.469, + 0.681 + ], + "angle": 0, + "content": "After the painting branch returns the inpainted image \\( I_{c} \\), we get the final result by using Eq. 1." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.688, + 0.182, + 0.704 + ], + "angle": 0, + "content": "3.2. Training" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.711, + 0.47, + 0.862 + ], + "angle": 0, + "content": "To train MI-GAN we use a combination of an adversarial and a knowledge distillation loss functions \\(\\mathcal{L}_{adv}\\) and \\(\\mathcal{L}_{KD}\\) respectively. For an adversarial training we borrow the discriminator architecture from StyleGAN [27] and replace convolutional layers with depthwise-separable convolutions. Also, similar to StyleGAN [27], we utilize a nonsaturating (with softplus non-linearity) loss function with \\(R_{1}\\)-regularization [41] for discriminator training. For the generator MI-GAN the adversarial component of the loss function will accordingly be as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.091, + 0.87, + 0.469, + 0.902 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {a d v} = \\mathbb {E} _ {x, m \\sim P _ {c, m}} [ S o f t P l u s (- D _ {w} (G _ {\\theta} (x, m), m)) ], \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.446, + 0.892, + 0.505 + ], + "angle": 0, + "content": "where \\(P_{c,m}\\) is the joint distribution of corrupted images (which should be inpainted) and the corresponding missing regions, \\(D_w\\) is the discriminator, and \\(G_{\\theta}\\) is the generator, i.e. our MI-GAN." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.506, + 0.893, + 0.612 + ], + "angle": 0, + "content": "For a knowledge distillation we choose Co-Mod-GAN [65] as a teacher network for MI-GAN due to its strong generative ability inherited from StyleGAN-v2 [54]. Similar to us, inspired by StyleGAN, Co-Mod-GAN also has a painting branch. Hence we put a knowledge-distillation loss between the inpainted regions of intermediate results of the painting branches of Co-Mod-GAN and MI-GAN:" + }, + { + "type": "equation", + "bbox": [ + 0.566, + 0.619, + 0.892, + 0.66 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {K D} = \\sum_ {i = 0} ^ {3} \\| \\left(x _ {i} - x _ {i} ^ {C}\\right) \\odot (1 - M _ {i}) \\|, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.668, + 0.892, + 0.76 + ], + "angle": 0, + "content": "where \\( x_{i} \\) and \\( x_{i}^{C} \\) are the intermediate results of painting branches of MI-GAN and Co-Mod-GAN respectively, and \\( M_{i} \\in \\{0,1\\}^{\\frac{H}{2^{i}} \\times \\frac{W}{2^{i}}} \\) is obtained by resizing the binary mask \\( M \\) to the size of \\( x_{i} \\) (with the nearest neighbour interpolation). In Sec. 4.6 we discuss the effect of knowledge distillation loss." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.762, + 0.892, + 0.792 + ], + "angle": 0, + "content": "So the final loss function for MI-GAN generator will be the weighted combination" + }, + { + "type": "equation", + "bbox": [ + 0.613, + 0.801, + 0.891, + 0.817 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} = \\lambda_ {1} \\mathcal {L} _ {a d v} + \\lambda_ {2} \\mathcal {L} _ {K D}. \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.825, + 0.792, + 0.84 + ], + "angle": 0, + "content": "In our experiments we take \\(\\lambda_1 = 1, \\lambda_2 = 2\\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.848, + 0.743, + 0.862 + ], + "angle": 0, + "content": "3.3. Model Re-Parametrization" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Re-parametrization is widely used for such tasks as compact model design [29], neural architecture search [11, 63]" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "7338" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.089, + 0.472, + 0.213 + ], + "angle": 0, + "content": "
MethodFFHQPlaces2FLOPS (GFLOPS)Params (×106)
FID ↓LPIPS ↓FID ↓LPIPS ↓
LaMa32.710.25922.000.37832.0527.05
Co-Mod-GAN4.700.2579.320.39791.2179.17
SH-GAN4.330.2547.400.39291.2779.21
ZITS--16.780.356295.7278.49
MAT7.000.23114.380.394140.7459.78
LDM--13.400.3856,896.16387.25
HiFill--81.270.48818.142.72
MI-GAN (ours)4.990.25711.830.39411.195.95
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.219, + 0.47, + 0.248 + ], + "angle": 0, + "content": "Table 1. Quantitative comparison of our method with state-of-the-art approaches on 256 resolution images." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.271, + 0.469, + 0.36 + ], + "angle": 0, + "content": "and pruning [14]. Inspired by recent work on online reparametrization [23], we adopt the technique to our architecture. We skip the linear scaling layer, instead we use weight normalizations described in [49]. We apply the reparametrization for all convolution layers in MI-GAN architecture." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.362, + 0.47, + 0.483 + ], + "angle": 0, + "content": "For a convolutional layer \\(L_{i}\\) during training we define \\(n\\) kernels \\(\\omega_{i}^{1},\\omega_{i}^{2},\\ldots ,\\omega_{i}^{n}\\in \\mathbb{R}^{C_{O}\\times C_{I}\\times k\\times k}\\), where \\(C_O\\) and \\(C_I\\) are the numbers of output and input channels of \\(L_{i}\\) respectively (for depthwise convolutions \\(C_I = 1\\) regardless of input channel number of \\(L_{i}\\)), and \\(k\\) is the kernel size. Then we initialize the kernels randomly from standard normal distribution, combine them via summation, and scale the result to have standard deviation equal to 1:" + }, + { + "type": "equation", + "bbox": [ + 0.211, + 0.494, + 0.47, + 0.534 + ], + "angle": 0, + "content": "\\[\n\\omega_ {i} = \\frac {1}{\\sqrt {n}} \\sum_ {j = 1} ^ {n} \\omega_ {i} ^ {j}. \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.544, + 0.47, + 0.59 + ], + "angle": 0, + "content": "This follows by a weight normalization operation \\(\\hat{\\omega}_i = \\frac{\\omega_i}{\\|\\omega_i\\|}\\). Finally \\(\\hat{\\omega}_i\\) is being used as a convolutional (or depth-wise convolutional) kernel:" + }, + { + "type": "equation", + "bbox": [ + 0.18, + 0.602, + 0.47, + 0.619 + ], + "angle": 0, + "content": "\\[\nL _ {i} (x) = \\operatorname {C o n v} \\left(x, \\hat {\\omega} _ {i}\\right) + b _ {i}, \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.628, + 0.468, + 0.674 + ], + "angle": 0, + "content": "where \\( b_{i} \\) is the convolutional bias initialized with zeros. During inference all additional parameters are fused and \\( \\hat{\\omega}_{i} \\) is directly applied in Eq. 7." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.674, + 0.469, + 0.763 + ], + "angle": 0, + "content": "Our re-parametrization for depthwise-separable convolution blocks is shown in Fig. 3. In our experiments we take \\( n = 9 \\) to somehow \"compensate\" and make the network's capacity close to the capacity of its teacher network. The impact of the re-parametrization trick is discussed in Sec. 4.6." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.778, + 0.21, + 0.794 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.802, + 0.295, + 0.818 + ], + "angle": 0, + "content": "4.1. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Our experiments are conducted on Places2 [67] and FFHQ [27] datasets. Though our proposed model is fully convolutional, and can be used for inference on varying resolutions and aspect ratios, we create separate architectures for training on 256 and 512 resolution inputs. The purpose" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.152 + ], + "angle": 0, + "content": "of having separate architectures is to minimize the FLOPS and the memory usage for higher resolution inputs. The architectural details of our models can be found in the supplementary material." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.153, + 0.893, + 0.273 + ], + "angle": 0, + "content": "To train our models on Places2 dataset we use Places365-Standard subset, which contains \\(\\sim 1.8\\) million images. All the metrics are calculated on Places2 validation set with 36,500 images. For 256 and 512 resolution models we train them for \\(\\sim 950,000\\) and \\(\\sim 1,600,000\\) iterations respectively. The training time for 256 and 512 resolution models was 23 days with 2 Nvidia Quadro-RTX 8000 GPUs and 30 days with 8 Nvidia A6000 GPUs respectively." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.274, + 0.892, + 0.349 + ], + "angle": 0, + "content": "We train the teacher Co-Mod-GAN model and our 256 resolution model on FFHQ by using randomly chosen 60,000 images, and evaluate all models on the rest 10,000 images. We train our model for \\(\\sim 800\\), 000 iterations for 10 days with 8 Nvidia A6000 GPUs." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.35, + 0.892, + 0.396 + ], + "angle": 0, + "content": "Adam optimizer is used with learning rate 0.001 and with \\(\\beta = (0,0.99)\\) both for the generator and the discriminator. We fix batch size 32 for all experiments." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.407, + 0.733, + 0.423 + ], + "angle": 0, + "content": "4.2. Quantitative Comparison" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.431, + 0.892, + 0.583 + ], + "angle": 0, + "content": "Tables 1 and 2 show comparison of our method with state-of-the-arts Co-Mod-GAN [65], SH-GAN [58], LaMa [53], LDM [46], ZITS [15], MAT [34] and HiFill [59] on Places2 and FFHQ datasets respectively. All the models besides Co-Mod-GAN are taken from their official repositories or are kindly provided by the corresponding authors. For Co-Mod-GAN we re-implemented it in PyTorch [43], and trained and tested the replicated version. The FID [21] scores of the replicated Co-Mod-GAN match the FID scores in the original paper." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.583, + 0.892, + 0.748 + ], + "angle": 0, + "content": "For the purpose of metric calculation we do the inference of all models in comparison using the free-form mask generation strategy as in Co-Mod-GAN [65]. The mask generation process combines multiple brush strokes and rectangles. The number of brush strokes is chosen randomly between 0 and 20. The widths of the brush strokes are chosen uniformly from the range (12, 40). Generated masks contain between 0 to 5 random rectangles up to the image size, and between 0 to 10 rectangles having maximum side fixed to the half of the image size. With this method of mask generation, masked area ratio varies between 0 and 1." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.892, + 0.84 + ], + "angle": 0, + "content": "We use Fréchet Inception Distance (FID) [21] as our primary metric. Also, we provide a comparison in terms of the perceptual metric LPIPS [64]. To show the computational complexity of the models we provide the number of floating point operations per second (FLOPS) and for the size of the models we report the number of model parameters." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.902 + ], + "angle": 0, + "content": "As can be noticed from Table 1, on Places2 dataset our model outperforms LaMa, ZITS, MAT and HiFill in terms of FID and is comparable with LDM, while slightly underperforms Co-Mod-GAN and SH-GAN being on par with" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "7339" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.078, + 0.088, + 0.891, + 0.453 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.459, + 0.885, + 0.473 + ], + "angle": 0, + "content": "Figure 4. Qualitative results of our model and other state of the art approaches on 256 resolution Places 2 samples with free-form masks." + }, + { + "type": "image", + "bbox": [ + 0.078, + 0.485, + 0.891, + 0.711 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.714, + 0.893, + 0.741 + ], + "angle": 0, + "content": "Figure 5. Example results of our 512 resolution model and other state of the art approaches on 512 resolution Places2 test samples using free-form and user masks. Please zoom for a better view." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.473, + 0.901 + ], + "angle": 0, + "content": "them in terms of the perceptual metric LPIPS. However MI-GAN is almost 8 times faster and 13 times lighter than Co-Mod-GAN and SH-GAN. This emphasizes a great generative ability of MI-GAN while being a compact model designed for mobile devices. Let us notice that LDM and MAT does not provide a model working on 256 resolution, so to inference on 256 resolution we resize images to 512, process them with 512 models and then resize back to 256. On FFHQ we can observe a similar picture, while our" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.892, + 0.84 + ], + "angle": 0, + "content": "method is even closer to Co-Mod-GAN and SH-GAN (i.e. has similar generative ability). For LaMa to inference on FFHQ dataset we have used the model trained on CelebA [38] dataset. LDM, ZITS and HiFill do not provide an inpainting model trained on faces." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.893, + 0.901 + ], + "angle": 0, + "content": "For the image resolution 512 MI-GAN performs similarly to LaMa and ZITS in terms of FID and slightly underperforms Co-Mod-GAN, SH-GAN, LDM and MAT. Qualitative analysis performed in Sec. 4.3 shows that the small" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "7340" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.083, + 0.133, + 0.099, + 0.143 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "image", + "bbox": [ + 0.097, + 0.09, + 0.285, + 0.194 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.287, + 0.133, + 0.303, + 0.142 + ], + "angle": 0, + "content": "(b)" + }, + { + "type": "image", + "bbox": [ + 0.306, + 0.089, + 0.472, + 0.194 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.474, + 0.089, + 0.556, + 0.194 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.557, + 0.089, + 0.639, + 0.194 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.64, + 0.089, + 0.722, + 0.194 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.723, + 0.089, + 0.805, + 0.194 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.806, + 0.089, + 0.892, + 0.194 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.199, + 0.892, + 0.213 + ], + "angle": 0, + "content": "Figure 6. (a) Total rating of each method based on our user study. (b) Visual examples from the user study. Please zoom-in for better view." + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.236, + 0.468, + 0.449 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.452, + 0.468, + 0.48 + ], + "angle": 0, + "content": "Figure 7. Qualitative results from our model and other approaches on FFHQ dataset samples. Please zoom for a better view." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.506, + 0.468, + 0.566 + ], + "angle": 0, + "content": "difference in terms of FID has a small impact on visual results. Instead, our model is more than 7.5 times faster and 4.5 times lighter than the mentioned state-of-the-art approaches (see Table 2)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.567, + 0.468, + 0.701 + ], + "angle": 0, + "content": "Notice that even though HiFill has less number of parameters compared to our approach, MI-GAN is computationally more efficient and significantly outperforms HiFill quantitatively both on 256 and 512 resolutions. The reason that our model is computationally more efficient is that MI-GAN is a single-stage fully convolutional network consisting of depthwise-separable convolutions, whereas HiFill uses regular convolutions on higher resolution features and has a costly attention mechanism in its refinement network." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.702, + 0.468, + 0.793 + ], + "angle": 0, + "content": "To show the effectiveness of our approach on different mask sizes, we provide FID comparisons with varying mask ratios in the appendix. Additionally, in order to further prove the robustness of our approach against other metrics, we also include a comparison in terms of PSNR, SSIM [55], P-IDS and U-IDS [65] metrics in the appendix." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.802, + 0.299, + 0.818 + ], + "angle": 0, + "content": "4.3. Qualitative Comparison" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.826, + 0.468, + 0.901 + ], + "angle": 0, + "content": "In this subsection we discuss the qualitative advantages of our model over some state-of-the-art approaches. As illustrated in Fig. 4 our model produces semantically meaningful content, even if the input mask is large. Our model has a strong generative capability, and the results are sharp," + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.236, + 0.892, + 0.389 + ], + "angle": 0, + "content": "
MethodFID ↓LPIPS ↓FLOPS (GFLOPS)Parameters (×106)
LaMa12.360.314128.0627.05
Co-Mod-GAN8.050.343121.0979.79
SH-GAN7.030.339121.1579.82
ZITS12.940.310666.9778.49
MAT8.670.339288.7861.56
LDM8.460.34227,581.56387.25
HiFill64.070.43872.122.72
MI-GAN (ours)10.000.34515.695.98
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.395, + 0.891, + 0.424 + ], + "angle": 0, + "content": "Table 2. Quantitative comparison of our method with state-of-the-art approaches on 512 resolution images." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.451, + 0.892, + 0.542 + ], + "angle": 0, + "content": "while approaches like LaMa [53] and ZITS [15] produce blurry results on larger masks (see the 1st row of the figure as an example). Besides, as can be noticed from the qualitative comparison, on 256 resolution images our approach can perform better than the bigger and exceedingly computationally expensive model LDM [46]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.543, + 0.892, + 0.619 + ], + "angle": 0, + "content": "On higher resolution images (see Fig. 5) our model still produces semantically meaningful results. Besides, our results don't have a color inconsistency issue unlike LDM, LaMa and ZITS results (see the 1st row of the figure as an exemple)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.62, + 0.892, + 0.68 + ], + "angle": 0, + "content": "We also conduct a qualitative comparison on face images (see Fig. 7). On face images our model's results are on par with Co-Mod-GAN and SH-GAN, while being better than LaMa and MAT." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.682, + 0.891, + 0.711 + ], + "angle": 0, + "content": "More qualitative results can be found in the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.725, + 0.622, + 0.741 + ], + "angle": 0, + "content": "4.4. User Study" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.892, + 0.901 + ], + "angle": 0, + "content": "In addition to comparing our MI-GAN model with SOTA inpainting methods, we conduct a user study against 5 built-in commercial mobile image inpainting apps. For this, we select a diverse set of 20 real world photos from OpenImages [30] dataset with varying resolutions and, using each method in comparison, carefully mask and remove predetermined objects from each photo. Then, we ask 3 people to anonymously rate each of 5 results from 1 to 5 for each photo and sum the given ratings for each method (see Fig. 6.a). As can be seen from the diagram, our approach has a" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "7341" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.089, + 0.473, + 0.239 + ], + "angle": 0, + "content": "
Device Name256-resolution
MI-GAN speed (ms, mean/std)Co-Mod-GAN speed (ms, mean/std)
iPhone71030.25 / 13.374475.33 / 39.55
iPhoneX630.80 / 12.212746.00 / 28.84
iPad mini (5th gen)552.40 / 8.102686.17 / 41.41
iPhone14-pro-max296.00 / 1.351374.40 / 84.78
Galaxy Tab S7+686.17 / 12.36- / -
Samsung Galaxy S81476.40 / 5.98- / -
vivo Y122918.08 / 33.47- / -
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.076, + 0.245, + 0.47, + 0.318 + ], + "angle": 0, + "content": "Table 3. The actual speed of our 256 model vs Co-Mod-GAN 256 model deployed on various mobile devices. The actual speed is measured in milliseconds, the means and the stds of the speed are presented for each mobile device. Some numbers are missing, since Co-Mod-GAN was providing an out of memory error." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.345, + 0.471, + 0.406 + ], + "angle": 0, + "content": "clear advantage over other methods. Fig. 6.b shows qualitative samples from user study, where our result has obvious advantage over commercial mobile apps. We include more results in the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.422, + 0.36, + 0.439 + ], + "angle": 0, + "content": "4.5. Actual Speed on Mobile Devices" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.448, + 0.47, + 0.553 + ], + "angle": 0, + "content": "Besides calculating FLOPS we also measure actual speed of our method on real mobile devices and compare MI-GAN with Co-Mod-GAN. As can be noticed from Table 3 on 256 resolution inputs our method is more than 4 times faster on average than Co-Mod-GAN, which allows MI-GAN to be used in real-world applications on mobile devices." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.556, + 0.471, + 0.678 + ], + "angle": 0, + "content": "All models in Table 3 are using CPUs of mobile devices and are deployed by using the neural network framework ONNX [3]. Nothing special was conducted to optimize the speed or memory usage of MI-GAN on ONNX, so we believe MI-GAN can be further optimized in terms of speed or memory consumption (particularly running it on GPUs of mobile devices). The actual running times on 512 resolution images can be found in the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.694, + 0.231, + 0.71 + ], + "angle": 0, + "content": "4.6. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.471, + 0.903 + ], + "angle": 0, + "content": "In this subsection we show the impact of our re-parametrization trick and knowledge distillation loss function for MI-GAN 256 resolution model. Both are designed to close the generative performance gap between MI-GAN and a larger inpainting network. Table 4 shows the quantitative effect of both. Fig. 8 shows that by adding re-parametrization trick we increase the semantic understanding of the model to generate more meaningful results. Further, the knowledge distillation adds more generative ability. Although both modifications has positive impact, one can notice that re-parametrization trick improves the method drastically (see also Fig. 8)." + }, + { + "type": "table", + "bbox": [ + 0.514, + 0.089, + 0.878, + 0.164 + ], + "angle": 0, + "content": "
MethodFID ↓LPIPS ↓
Baseline14.940.407
Baseline + Re-Param12.220.400
MI-GAN: Baseline + Re-Param + KD11.830.39
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.499, + 0.168, + 0.894, + 0.211 + ], + "angle": 0, + "content": "Table 4. The effect of model re-parametrization and knowledge distillation on MI-GAN 256 resolution model. As can be noticed both have positive impact in terms of both metrics FID and LPIPS." + }, + { + "type": "image", + "bbox": [ + 0.502, + 0.241, + 0.895, + 0.481 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.485, + 0.892, + 0.514 + ], + "angle": 0, + "content": "Figure 8. Visual results of ablation study on model reparametrization and knowledge distillation." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.555, + 0.795, + 0.573 + ], + "angle": 0, + "content": "5. Limitations and Societal Impact" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.59, + 0.892, + 0.711 + ], + "angle": 0, + "content": "Although our method has good generation abilities producing visually plausible results, similar to other state-of-the-art approaches it sometimes meets difficulties when reconstructing complex 3D structures. We hypothesize this can be later improved by guiding the network with more information about the 3D structure of the objects in images. For visual examples of MI-GAN's failure cases please see our supplementary material." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.893, + 0.902 + ], + "angle": 0, + "content": "Our work aims to make the creative image editing easier and accessible for everyone with their mobile devices. Similar to other deep learning based image editing approaches our method may have both positive and negative societal impact depending on its application. As a positive impact MI-GAN can help the users to restore old photos or remove unpleasant objects from their photos making them more aesthetic. On the negative side it can be used to misrepresent the reality by removing important facts from the images. We strongly believe and hope that our work will give more positive value to creative editing users than its potential negative societal impact." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "7342" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.091, + 0.196, + 0.106 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.115, + 0.473, + 0.252 + ], + "angle": 0, + "content": "In this paper we introduce MI-GAN, the first generative mobile image inpainting network. By using depthwise separable convolutions, model re-parametrization, and knowledge distillation, MI-GAN is able to produce high-quality results while having a low computational cost and a small number of parameters. Qualitative and quantitative comparisons show that MI-GAN is comparable or sometimes outperforms the current state-of-the-art approaches while being a way faster and smaller." + }, + { + "type": "title", + "bbox": [ + 0.079, + 0.266, + 0.175, + 0.281 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.29, + 0.47, + 0.346 + ], + "angle": 0, + "content": "[1] Angeline Aguinaldo, Ping-Yeh Chiang, Alex Gain, Ameya Patil, Kolten Pearson, and Soheil Feizi. Compressing gans using knowledge distillation. arXiv preprint arXiv:1902.00159, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.347, + 0.47, + 0.389 + ], + "angle": 0, + "content": "[2] Michael Ashikhmin. Synthesizing natural textures. In Proceedings of the 2001 symposium on Interactive 3D graphics, pages 217-226, 2001. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.391, + 0.469, + 0.431 + ], + "angle": 0, + "content": "[3] Junjie Bai, Fang Lu, Ke Zhang, et al. Onnx: Open neural network exchange. https://github.com/onnx/onnx, 2019.8" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.433, + 0.469, + 0.489 + ], + "angle": 0, + "content": "[4] Connelly Barnes, Eli Shechtman, Adam Finkelstein, and Dan B Goldman. Patchmatch: A randomized correspondence algorithm for structural image editing. ACM Trans. Graph., 28(3):24, 2009. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.49, + 0.469, + 0.546 + ], + "angle": 0, + "content": "[5] Marcelo Bertalmio, Guillermo Sapiro, Vincent Caseles, and Coloma Ballester. Image inpainting. In Proceedings of the 27th annual conference on Computer graphics and interactive techniques, pages 417-424, 2000. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.547, + 0.469, + 0.602 + ], + "angle": 0, + "content": "[6] Marcelo Bertalmio, Luminita Vese, Guillermo Sapiro, and Stanley Osher. Simultaneous structure and texture image inpainting. IEEE transactions on image processing, 12(8):882-889, 2003. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.604, + 0.469, + 0.645 + ], + "angle": 0, + "content": "[7] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. arXiv preprint arXiv:1809.11096, 2018.3" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.647, + 0.469, + 0.688 + ], + "angle": 0, + "content": "[8] Tony F Chan and Jianhong Shen. Nontexture inpainting by curvature-driven diffusions. Journal of visual communication and image representation, 12(4):436-449, 2001. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.689, + 0.469, + 0.731 + ], + "angle": 0, + "content": "[9] Ting-Yun Chang and Chi-Jen Lu. Tinygan: Distilling big-gan for conditional image generation. In Proceedings of the Asian Conference on Computer Vision, 2020. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.732, + 0.469, + 0.802 + ], + "angle": 0, + "content": "[10] Hanting Chen, Yunhe Wang, Han Shu, Changyuan Wen, Chunjing Xu, Boxin Shi, Chao Xu, and Chang Xu. Distilling portable generative adversarial networks for image translation. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 3585-3592, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.803, + 0.469, + 0.844 + ], + "angle": 0, + "content": "[11] Shoufa Chen, Yunpeng Chen, Shuicheng Yan, and Jiashi Feng. Efficient differentiable neural architecture search with meta kernels. ArXiv, abs/1912.04749, 2019. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[12] Yunjey Choi, Youngjung Uh, Jaejun Yoo, and Jung-Woo Ha. Stargan v2: Diverse image synthesis for multiple domains. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 8188-8197, 2020. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.29, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "[13] Antonio Criminisi, Patrick Pérez, and Kentaro Toyama. Region filling and object removal by exemplar-based image inpainting. IEEE Transactions on image processing, 13(9):1200-1212, 2004. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.15, + 0.892, + 0.22 + ], + "angle": 0, + "content": "[14] Xiaohan Ding, Tianxiang Hao, Jianchao Tan, Ji Liu, Jungong Han, Yuchen Guo, and Guiguang Ding. Resrep: Lossless cnn pruning via decoupling remembering and forgetting. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4510-4520, 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.222, + 0.892, + 0.291 + ], + "angle": 0, + "content": "[15] Qiaole Dong, Chenjie Cao, and Yanwei Fu. Incremental transformer structure enhanced image inpainting with masking positional encoding. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11358-11368, 2022. 2, 5, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.293, + 0.892, + 0.349 + ], + "angle": 0, + "content": "[16] Alexei A Efros and William T Freeman. Image quilting for texture synthesis and transfer. In Proceedings of the 28th annual conference on Computer graphics and interactive techniques, pages 341-346, 2001. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.351, + 0.892, + 0.406 + ], + "angle": 0, + "content": "[17] Alexei A Efros and Thomas K Leung. Texture synthesis by non-parametric sampling. In Proceedings of the seventh IEEE international conference on computer vision, volume 2, pages 1033-1038. IEEE, 1999. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.408, + 0.754, + 0.422 + ], + "angle": 0, + "content": "[18] ADVA Soft GmbH. Touchretouch. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.424, + 0.892, + 0.479 + ], + "angle": 0, + "content": "[19] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. Communications of the ACM, 63(11):139–144, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.481, + 0.891, + 0.51 + ], + "angle": 0, + "content": "[20] Paul Harrison. A non-hierarchical procedure for re-synthesis of complex textures. 2001. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.511, + 0.892, + 0.58 + ], + "angle": 0, + "content": "[21] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in neural information processing systems, 30, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.583, + 0.892, + 0.625 + ], + "angle": 0, + "content": "[22] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Advances in Neural Information Processing Systems, 33:6840-6851, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.627, + 0.892, + 0.696 + ], + "angle": 0, + "content": "[23] Mu Hu, Junyi Feng, Jiashen Hua, Baisheng Lai, Jianqiang Huang, Xiaojin Gong, and Xian-Sheng Hua. Online convolutional re-parameterization. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 568-577, 2022. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.698, + 0.808, + 0.713 + ], + "angle": 0, + "content": "[24] Adobe Inc. Photoshop express photo editor. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.714, + 0.791, + 0.728 + ], + "angle": 0, + "content": "[25] Picsart Inc. Picsart photo editor & video. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.731, + 0.892, + 0.771 + ], + "angle": 0, + "content": "[26] Paras Kapoor and Tien D. Bui. Tinystargan v2: Distilling stargan v2 for efficient diverse image synthesis for multiple domains. In BMVC, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.774, + 0.892, + 0.842 + ], + "angle": 0, + "content": "[27] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In 2019 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4396-4405, 2019. 1, 3, 4, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.845, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[28] Rolf Kohler, Christian Schuler, Bernhard Schölkopf, and Stefan Harmeling. Mask-specific inpainting with deep neural networks. In German conference on pattern recognition, pages 523-534. Springer, 2014. 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "7343" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.189 + ], + "angle": 0, + "content": "[29] Alexander Kolesnikov, Alexey Dosovitskiy, Dirk Weissenborn, Georg Heigold, Jakob Uszkoreit, Lucas Beyer, Matthias Minderer, Mostafa Dehghani, Neil Houlsby, Sylvain Gelly, Thomas Unterthiner, and Xiaohua Zhai. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations (ICLR), 2021. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.191, + 0.472, + 0.274 + ], + "angle": 0, + "content": "[30] Alina Kuznetsova, Hassan Rom, Neil Alldrin, Jasper Uijlings, Ivan Krasin, Jordi Pont-Tuset, Shahab Kamali, Stefan Popov, Matteo Malloci, Alexander Kolesnikov, Tom Duerig, and Vittorio Ferrari. The open images dataset v4: Unified image classification, object detection, and visual relationship detection at scale. IJCV, 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.276, + 0.47, + 0.331 + ], + "angle": 0, + "content": "[31] Vivek Kwatra, Arno Schödl, Irfan Essa, Greg Turk, and Aaron Bobick. Graphcut textures: Image and video synthesis using graph cuts. Acm transactions on graphics (tog), 22(3):277-286, 2003. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.333, + 0.47, + 0.375 + ], + "angle": 0, + "content": "[32] Anat Levin, Assaf Zomet, and Yair Weiss. Learning how to inpaint from global image statistics. In ICCV, volume 1, pages 305-312, 2003. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.376, + 0.47, + 0.432 + ], + "angle": 0, + "content": "[33] Jingyuan Li, Ning Wang, Lefei Zhang, Bo Du, and Dacheng Tao. Recurrent feature reasoning for image inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7760-7768, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.433, + 0.47, + 0.501 + ], + "angle": 0, + "content": "[34] Wenbo Li, Zhe Lin, Kun Zhou, Lu Qi, Yi Wang, and Jiaya Jia. Mat: Mask-aware transformer for large hole image inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10758-10768, 2022. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.503, + 0.47, + 0.56 + ], + "angle": 0, + "content": "[35] Zeqi Li, Ruowei Jiang, and Parham Aarabi. Semantic relation preserving knowledge distillation for image-to-image translation. In European conference on computer vision, pages 648-663. Springer, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.561, + 0.47, + 0.63 + ], + "angle": 0, + "content": "[36] Guilin Liu, Fitsum A Reda, Kevin J Shih, Ting-Chun Wang, Andrew Tao, and Bryan Catanzaro. Image inpainting for irregular holes using partial convolutions. In Proceedings of the European conference on computer vision (ECCV), pages 85-100, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.631, + 0.47, + 0.699 + ], + "angle": 0, + "content": "[37] Yuchen Liu, Zhixin Shu, Yijun Li, Zhe Lin, Federico Peruzzi, and Sun-Yuan Kung. Content-aware gan compression. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12156-12166, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.702, + 0.47, + 0.758 + ], + "angle": 0, + "content": "[38] Ziwei Liu, Ping Luo, Xiaogang Wang, and Xiaou Tang. Deep learning face attributes in the wild. In Proceedings of International Conference on Computer Vision (ICCV), December 2015. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.759, + 0.27, + 0.774 + ], + "angle": 0, + "content": "[39] Google LLC. Snapseed. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.775, + 0.47, + 0.844 + ], + "angle": 0, + "content": "[40] Andreas Lugmayr, Martin Danelljan, Andres Romero, Fisher Yu, Radu Timofte, and Luc Van Gool. Repaint: Inpainting using denoising diffusion probabilistic models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11461-11471, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.845, + 0.47, + 0.9 + ], + "angle": 0, + "content": "[41] Lars Mescheder, Andreas Geiger, and Sebastian Nowozin. Which training methods for gans do actually converge? In International conference on machine learning, pages 3481-3490. PMLR, 2018. 4" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.472, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.893, + 0.135 + ], + "angle": 0, + "content": "[42] Shant Navasardyan and Marianna Ohanyan. The family of onion convolutions for image inpainting. International Journal of Computer Vision, pages 1-30, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.893, + 0.261 + ], + "angle": 0, + "content": "[43] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, Luca Antiga, Alban Desmaison, Andreas Kopf, Edward Yang, Zachary DeVito, Martin Raison, Alykhan Tejani, Sasank Chilamkurthy, Benoit Steiner, Lu Fang, Junjie Bai, and Soumith Chintala. Pytorch: An imperative style, high-performance deep learning library. In Advances in Neural Information Processing Systems 32, pages 8024-8035. Curran Associates, Inc., 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.262, + 0.893, + 0.304 + ], + "angle": 0, + "content": "[44] Jimmy S Ren, Li Xu, Qiong Yan, and Wenxiu Sun. Shepard convolutional neural networks. Advances in neural information processing systems, 28, 2015. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.305, + 0.893, + 0.36 + ], + "angle": 0, + "content": "[45] Yuxi Ren, Jie Wu, Xuefeng Xiao, and Jianchao Yang. Online multi-granularity distillation for gan compression. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6793-6803, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.362, + 0.894, + 0.432 + ], + "angle": 0, + "content": "[46] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684-10695, 2022. 2, 5, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.433, + 0.893, + 0.503 + ], + "angle": 0, + "content": "[47] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image computing and computer-assisted intervention, pages 234-241. Springer, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.504, + 0.893, + 0.572 + ], + "angle": 0, + "content": "[48] Chitwan Sahara, William Chan, Huiwen Chang, Chris Lee, Jonathan Ho, Tim Salimans, David Fleet, and Mohammad Norouzi. Palette: Image-to-image diffusion models. In ACM SIGGRAPH 2022 Conference Proceedings, pages 1-10, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.574, + 0.893, + 0.63 + ], + "angle": 0, + "content": "[49] Tim Salimans and Durk P Kingma. Weight normalization: A simple reparameterization to accelerate training of deep neural networks. Advances in neural information processing systems, 29, 2016. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.631, + 0.893, + 0.673 + ], + "angle": 0, + "content": "[50] Jianhong Shen and Tony F Chan. Mathematical models for local nontexture inpaintings. SIAM Journal on Applied Mathematics, 62(3):1019-1043, 2002. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.674, + 0.893, + 0.703 + ], + "angle": 0, + "content": "[51] L Sifre and S Mallat. Rigid-motion scattering for image classification [phd thesis]. Ecole Polytechnique, 2014. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.704, + 0.893, + 0.745 + ], + "angle": 0, + "content": "[52] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. arXiv preprint arXiv:2010.02502, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.747, + 0.893, + 0.844 + ], + "angle": 0, + "content": "[53] Roman Suvorov, Elizaveta Logacheva, Anton Mashikhin, Anastasia Remizova, Armenii Ashukha, Aleksei Silvestrov, Naejin Kong, Harshith Goka, Kiwoong Park, and Victor Lempitsky. Resolution-robust large mask inpainting with fourier convolutions. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 2149–2159, 2022. 2, 5, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.845, + 0.893, + 0.9 + ], + "angle": 0, + "content": "[54] Yuri Viazovetskyi, Vladimir Ivashkin, and Evgeny Kashin. Stylegan2 distillation for feed-forward image manipulation. In European conference on computer vision, pages 170-186. Springer, 2020. 2, 4" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "7344" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.148 + ], + "angle": 0, + "content": "[55] Z. Wang, E.P. Simoncelli, and A.C. Bovik. Multiscale structural similarity for image quality assessment. In The Thirty-Seventh Asilomar Conference on Signals, Systems & Computers, 2003, volume 2, pages 1398-1402 Vol.2, 2003. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.149, + 0.47, + 0.205 + ], + "angle": 0, + "content": "[56] Li-Yi Wei and Marc Levoy. Fast texture synthesis using tree-structured vector quantization. In Proceedings of the 27th annual conference on Computer graphics and interactive techniques, pages 479–488, 2000. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.206, + 0.47, + 0.248 + ], + "angle": 0, + "content": "[57] Junyuan Xie, Linli Xu, and Enhong Chen. Image denoising and inpainting with deep neural networks. Advances in neural information processing systems, 25, 2012. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.248, + 0.47, + 0.318 + ], + "angle": 0, + "content": "[58] Xingqian Xu, Shant Navasardyan, Vahram Tadevosyan, Andranik Sargsyan, Yadong Mu, and Humphrey Shi. Image completion with heterogeneously filtered spectral hints. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, 2023. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.318, + 0.47, + 0.387 + ], + "angle": 0, + "content": "[59] Zili Yi, Qiang Tang, Shekoofeh Azizi, Daesik Jang, and Zhan Xu. Contextual residual aggregation for ultra high-resolution image inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7508-7517, 2020. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.388, + 0.47, + 0.445 + ], + "angle": 0, + "content": "[60] Jiahui Yu, Zhe Lin, Jamei Yang, Xiaohui Shen, Xin Lu, and Thomas S Huang. Free-form image inpainting with gated convolution. In Proceedings of the IEEE/CVF international conference on computer vision, pages 4471-4480, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.445, + 0.469, + 0.499 + ], + "angle": 0, + "content": "[61] Linfeng Zhang, Xin Chen, Runpei Dong, and Kaisheng Ma. Region-aware knowledge distillation for efficient image-to-image translation. arXiv preprint arXiv:2205.12451, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.501, + 0.469, + 0.571 + ], + "angle": 0, + "content": "[62] Linfeng Zhang, Xin Chen, Xiaobing Tu, Pengfei Wan, Ning Xu, and Kaisheng Ma. Wavelet knowledge distillation: Towards efficient image-to-image translation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12464-12474, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.571, + 0.469, + 0.613 + ], + "angle": 0, + "content": "[63] Mingyang Zhang, Xinyi Yu, Jingtao Rong, Linlin Ou, and Feng Gao. Repnas: Searching for efficient re-parameterizing blocks. arXiv preprint arXiv:2109.03508, 2021. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.614, + 0.469, + 0.683 + ], + "angle": 0, + "content": "[64] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 586-595, 2018. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.684, + 0.469, + 0.753 + ], + "angle": 0, + "content": "[65] Shengyu Zhao, Jonathan Cui, Yilun Sheng, Yue Dong, Xiao Liang, Eric I Chang, and Yan Xu. Large scale image completion via co-modulated generative adversarial networks. In International Conference on Learning Representations (ICLR), 2021. 2, 3, 4, 5, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.755, + 0.469, + 0.824 + ], + "angle": 0, + "content": "[66] Haitian Zheng, Zhe Lin, Jingwan Lu, Scott Cohen, Eli Shechtman, Connelly Barnes, Jianming Zhang, Ning Xu, Sohrab Amirghodsi, and Jiebo Luo. Cm-gan: Image inpainting with cascaded modulation gan and object-aware training. arXiv preprint arXiv:2203.11947, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.825, + 0.469, + 0.893 + ], + "angle": 0, + "content": "[67] Bolei Zhou, Agata Lapedriza, Aditya Khosla, Aude Oliva, and Antonio Torralba. Places: A 10 million image database for scene recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 40(6):1452-1464, 2018. 1, 5" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.893 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "7345" + } + ] +] \ No newline at end of file diff --git a/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/af22c1bd-1590-4032-ac12-a1b776021514_origin.pdf b/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/af22c1bd-1590-4032-ac12-a1b776021514_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..0aaefa548400e27bd9e2e6e5d12b8c8736500492 --- /dev/null +++ b/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/af22c1bd-1590-4032-ac12-a1b776021514_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:155132442452e4974a64663c600e9bf8c9191847648a7172d3d1d7629e89d962 +size 8565433 diff --git a/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/full.md b/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/full.md new file mode 100644 index 0000000000000000000000000000000000000000..ff0e280406d60bcd0c8d183d7b37d10b27773a16 --- /dev/null +++ b/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/full.md @@ -0,0 +1,341 @@ +# MI-GAN: A Simple Baseline for Image Inpainting on Mobile Devices + +Andranik Sargsyan1, Shant Navasardyan1, Xingqian Xu1,2, Humphrey Shi1,2 + +1Picsart AI Research (PAIR), 2SHI Labs @ Georgia Tech, Oregon & UIUC + +![](images/bb7f114aaaa5bbefa86f556e4e918b2e2aa20967b6a906441865aab834372745.jpg) + +![](images/d164b12f6472219fbe504753207c4b1de06f28efe3ecd28b8c4a6cba9ded6416.jpg) +Figure 1. The proposed approach can produce plausible results both on complex scene images as well as on face images. The scene image inputs are taken from the Places 2 [67] dataset and the face image input is from FFHQ [27] dataset. The bubble chart on the right shows the advantage of our network over state-of-the-art approaches. The size of the bubble signifies the relative number of parameters of each approach and the number inside of the bubble shows the absolute number of model parameters. Our approach achieves a low FID, while being one order of magnitude smaller and faster than recent SOTA approaches. + +![](images/c0b63dbc8b9bf868f66c6546977f827871e09d743224dad746c7ddcfde2c0dc5.jpg) + +![](images/91cec3edb59fd48ace1155d068b8240420028b6f710ca15b23eb4c8141329c5b.jpg) + +![](images/4b708583e9b5bb964222019fb8c6a00928ced8705384dabb79cca5e94ed7ae76.jpg) + +![](images/4dc6b2c7f714cd9b3140f35ec68dd5f656fcdf3fea890da7b31b8a2e3eda18c1.jpg) + +![](images/bb3d5645c9c902fb69dee7f881a042fdeb08dec6c747afad0bbabff5baa6c6cb.jpg) + +# Abstract + +In recent years, many deep learning based image inpainting methods have been developed by the research community. Some of those methods have shown impressive image completion abilities. Yet, to the best of our knowledge, there is no image inpainting model designed to run on mobile devices. In this paper we present a simple image inpainting baseline, Mobile Inpainting GAN (MI-GAN), which is approximately one order of magnitude computationally cheaper and smaller than existing state-of-the-art inpainting models, and can be efficiently deployed on mobile devices. Excessive quantitative and qualitative evaluations show that MI-GAN performs comparable or, in some cases, better than recent state-of-the-art approaches. Moreover, we perform a user study comparing MI-GAN results with results from several commercial mobile inpainting applications, which clearly shows the advantage of MI-GAN in comparison to existing apps. With the purpose of high quality and efficient inpainting, we utilize an effective combination of adversarial training, model reparametrization, and knowledge distillation. Our models and code are publicly available at https://github.com/Picsart-AI-Research/MI-GAN. + +# 1. Introduction + +The task of image inpainting is to complete the missing regions in images in a realistic and visually plausible way. Image inpainting algorithms have found their applications in such problems as image restoration, removal of unwanted objects, etc. + +Nowadays, in the era of fast evolving gadgets, particularly smartphones, image/video editing applications are growing furiously. The usage of mobile devices for making creative visual content by professionals as well as by consumers shows a great increasing tendency. A lot of mobile applications such as Photoshop Express [24], Picsart [25], Snapseed [39], TouchRetouch [18] empower the users to create awesome content utilizing AI-powered tools. One of the most popular such tools, object remover, allows its users to remove unwanted objects (e.g. watermarks, lines, people or random objects in the background, etc.) from their photos. So millions of users every day benefit from image inpainting technologies integrated in various mobile applications. + +Current AI-based state-of-the-art inpainting algorithms + +such as Co-Mod-GAN [65], SH-GAN [58], LaMa [53], or LDM [46] include an inference of a heavyweight neural network, which is often not feasible to do on low-end mobile devices (see Tables 1, 2). Therefore the processing is being done on server-side resulting in dependency on Internet connection, speed, traffic and server usage costs for image editing companies. + +To address this problem we propose a simple baseline for high-quality mobile image inpainting which is an order of magnitude lighter and computationally more efficient than current state-of-the-art neural networks while showing similar or sometimes even better performance (see Fig. 1). + +Motivated by the generative nature of the image completion problem we design MI-GAN, Mobile Inpainting Generative Adversarial Network, which benefits from a hybrid system consisting of adversarial training, model reparametrization, and knowledge distillation. Thanks to adversarial nature of the MI-GAN training, image completion results appear to be visually plausible without producing blurry regions and pattern-like artifacts. Model reparametrization further increases the output quality at no cost of efficiency. Finally, knowledge distillation by a stronger network also improves the generative ability of MI-GAN. + +Due to excessive evaluations MI-GAN shows great performance in terms of both quantitative and qualitative comparison with existing state-of-the-art methods. + +To summarize, our contributions are three-fold. + +- We propose MI-GAN, to the best of our knowledge the first mobile generative image inpainting network. +- We develop a customized knowledge distillation method that is suitable for our model and problem, as well as we implement a model re-parametrization strategy which enhances the quality of results. +- While being computationally more efficient and lighter than the existing state-of-the-art image completion approaches, MI-GAN produces similar or even better image inpainting results. Furthermore, in comparison to existing commercial mobile inpainting applications, MI-GAN results are generally rated higher by human evaluators. + +# 2. Related Work + +# 2.1. Image Inpainting Methods + +The task of image inpainting was and is being actively investigated by researchers during past decades. Classical approaches use diffusion processes [5, 6, 50, 8, 32] or exemplar-based techniques [17, 56, 20, 2, 4, 16, 31, 13] for coherent image restoration and completion. Although the classical methods greatly recover textures and preserve image structures, they lack of semantic understanding of the + +image context. Hence learning-based approaches were developed and later improved. + +Early deep learning papers on image inpainting were trying to fill small missing regions by image-to-image discriminative models [57, 28, 44, 36]. Later, by using generative adversarial networks (GANs) [19], researchers were able to reach extra-high quality in image inpainting task [60, 42, 59, 33, 65, 53, 58, 66]. Some papers [36, 60, 42] additionally design special convolution layers to efficiently use the information in the known region of deep features. RFR [33] suggests a recurrent feature reasoning module which utilizes correlations between neighboring pixels to fill the missing pixels. With their contextual residual aggregation mechanism Yi et al. [59] enables ultra-high resolution inpainting (up to 8K). Several methods [65, 58, 66] benefit from a strong generative model StyleGAN-v2 [54] and make adoptions to image inpainting task. [65] introduces co-modulation blocks conditioning StyleGAN-v2 modulated architecture with the input image. SH-GAN [58] introduces spectral hint units to generate high-frequency details. + +By benefiting from the Fourier analysis, LaMa [53] uses Fourier convolutions and greatly improves inpainting of repetitive patterns. ZITS [15] improves over LaMa by introducing a structure restoration mechanism with transformers. MAT [34] combines the strengths of convolutional and transformer-based models for large-hole inpainting. + +Recently, diffusion models [22, 52] were introduced and impacted the image inpainting task [46, 40, 48]. Palette [48] provides an image-conditioned diffusion model for image-to-image translation tasks, namely, colorization, inpainting/outpainting, and JPEG restoration. RePaint [40] adopts the unconditional pretrained Denoising Diffusion Probabilistic Model (DDPM) [22] for image inpainting task by guiding its backward process with inpainting masks. LDM [46] applies a diffusion process in its latent space which particularly allows conditioning on textual prompts, by so extending its image inpainting abilities to text guided completion. + +# 2.2. Lightweight Generative Modeling + +Although generative adversarial networks are able to create extremely high quality images often indistinguishable from reality with a naked eye, they require a tremendous amount of computations and memory consumption. For this purpose some methods [1, 10, 35, 9, 26, 45, 61, 62, 37] design lightweight generative models. [1] firstly applied the concept of knowledge distillation on GANs and showed incredible compression rates (e.g. 87:1 on CelebA [38]) while preserving the original quality. [10] utilizes the student discriminator in a triplet loss to enforce it benefit from teacher generated images also. In [35] the authors propose semantic preserving distillation loss for image-to + +![](images/7659809ef2490153e262f0eb228d0c0ce05731978583268bbcdbe07d4bc75dfa.jpg) +Figure 2. The overview of our method. The generator of MI-GAN consists of two branches: the main branch with a Unet like architecture and the painting branch. The main branch consists of a linear projection layer, depthwise separable convolutions, and bilinear resizing operations. The painting branch completes the missing region with layer-by-layer inpainting similar to the manual work of some experts. The training is conducted by using adversarial loss function and knowledge distillation. The discriminator is similar to the encoder of the main branch, having also residual connections and fully connected layers (more details can be found in supplementary material). As a teacher network in our experiments we take Co-Mod-GAN [65]. Please zoom in for better view. + +image translation task to preserve the semantic relations between the teacher and the student features. TinyGAN [9] and TinyStarGAN-v2 [26] are distilling high-fidelity image generation networks BigGAN [7] and Stargan-v2 [12] respectively. [45] proposes a GAN compression method with a student discriminator-free online distillation scheme. Recently in [62] the authors introduce wavelet knowledge distillation to transfer the high-frequency detail generating information from the teacher generative model to the student. [37] proposes a content-aware compression paradigm, which leverages generated contents to guide the process of pruning and distillation. + +# 3. Method + +# 3.1. Architecture + +We introduce a simple baseline for mobile image inpainting which benefits from a combination of adversarial learning, model re-parametrization, and knowledge distillation. Formally, given an input image $I_{orig} \in \mathbb{R}^{H \times W \times 3}$ and a binary mask $M \in \{0,1\}^{H \times W}$ indicating the known region with 1-values and the missing region with 0-values. MI-GAN takes the concatenated input $In = [I_{orig} \odot M, M] \in \mathbb{R}^{H \times W \times 4}$ and returns a completed image $I_c$ which is fi + +nally composited with the original image by using the binary mask $M$ : + +$$ +I _ {\text {c o m p o s}} = I _ {\text {o r i g}} \odot M + I _ {c} \odot (1 - M). \tag {1} +$$ + +The overview of our method is shown in Fig. 2. + +We design a generative adversarial network, the generator of which consists of two parts: a U-Net [47] like main branch utilizing depthwise separable convolution layers [51], and the painting branch imitating the inpainting process of experts. Being inspired by the architecture of StyleGAN [27], the concept of our painting branch is greatly aligned with the inpainting task. Indeed, similar to experts (artists), our painting branch paints the missing region iteratively layer-by-layer in the RGB-space starting from the overall structure and ending with the final result. + +The main branch architecture of MI-GAN starts with a convolution layer to project the 4-channel input space to a higher 128 dimension. Then a fully-convolutional encoder+decoder, consisting of depthwise separable convolutions and bilinear resizing operations, is applied resulting in a tensor with dimensionality $H \times W \times 128$ . All convolutional blocks are using the LeakyReLU activation. Inspired by StyleGAN, to generate high-frequency details, we also add a random noise component (with a learnable noise + +![](images/d8e69c3417c9470072454cf4fb2b47beb825397cbc42c352f4953b25a736ca64.jpg) +Figure 3. The structure of our depthwise separable convolution layers showing $(a)$ the model re-parametrization during training and $(b)$ the utilization of the fused weights during the inference. We apply bilinear resizing in the case when the depthwise separable convolution block changes its input resolution. In the case of both training and inference in each pointwise convolution layer a random noise with a trainable amplitude is applied. + +amplitude) to the pointwise convolution layers of the decoder of the main branch (see Fig. 3). The painting branch takes the intermediate tensors from the main branch decoder and "paints" them to the RGB-space with projection convolutional layers, resulting in images $x_{i} \in \mathbb{R}_{\frac{H}{2^{i}} \times \frac{W}{2^{i}} \times 3}^{\frac{H}{2^{i}} \times \frac{W}{2^{i}} \times 3}$ for $i = 0,1,\ldots,6$ . Then, the final image $I_{c} \in \mathbb{R}^{H \times W \times 3}$ is obtained by "painting" (adding) the images $x_{i}$ as layers on top of each other: $\hat{x}_6 = x_6$ , + +$$ +\begin{array}{c} \hat {x} _ {i} = B i l i n e a r U p (\hat {x} _ {i + 1}) + x _ {i}, i = 5, 4, \dots , 0, \\ I _ {c} = \hat {x} _ {0}, \end{array} \tag {2} +$$ + +where $BilinearUp$ is the bilinear upsampling operation with scaling factor equal to 2. + +After the painting branch returns the inpainted image $I_{c}$ , we get the final result by using Eq. 1. + +# 3.2. Training + +To train MI-GAN we use a combination of an adversarial and a knowledge distillation loss functions $\mathcal{L}_{adv}$ and $\mathcal{L}_{KD}$ respectively. For an adversarial training we borrow the discriminator architecture from StyleGAN [27] and replace convolutional layers with depthwise-separable convolutions. Also, similar to StyleGAN [27], we utilize a nonsaturating (with softplus non-linearity) loss function with $R_{1}$ -regularization [41] for discriminator training. For the generator MI-GAN the adversarial component of the loss function will accordingly be as follows: + +$$ +\mathcal {L} _ {a d v} = \mathbb {E} _ {x, m \sim P _ {c, m}} [ S o f t P l u s (- D _ {w} (G _ {\theta} (x, m), m)) ], \tag {3} +$$ + +where $P_{c,m}$ is the joint distribution of corrupted images (which should be inpainted) and the corresponding missing regions, $D_w$ is the discriminator, and $G_{\theta}$ is the generator, i.e. our MI-GAN. + +For a knowledge distillation we choose Co-Mod-GAN [65] as a teacher network for MI-GAN due to its strong generative ability inherited from StyleGAN-v2 [54]. Similar to us, inspired by StyleGAN, Co-Mod-GAN also has a painting branch. Hence we put a knowledge-distillation loss between the inpainted regions of intermediate results of the painting branches of Co-Mod-GAN and MI-GAN: + +$$ +\mathcal {L} _ {K D} = \sum_ {i = 0} ^ {3} \| \left(x _ {i} - x _ {i} ^ {C}\right) \odot (1 - M _ {i}) \|, \tag {4} +$$ + +where $x_{i}$ and $x_{i}^{C}$ are the intermediate results of painting branches of MI-GAN and Co-Mod-GAN respectively, and $M_{i} \in \{0,1\}^{\frac{H}{2^{i}} \times \frac{W}{2^{i}}}$ is obtained by resizing the binary mask $M$ to the size of $x_{i}$ (with the nearest neighbour interpolation). In Sec. 4.6 we discuss the effect of knowledge distillation loss. + +So the final loss function for MI-GAN generator will be the weighted combination + +$$ +\mathcal {L} = \lambda_ {1} \mathcal {L} _ {a d v} + \lambda_ {2} \mathcal {L} _ {K D}. \tag {5} +$$ + +In our experiments we take $\lambda_1 = 1, \lambda_2 = 2$ . + +# 3.3. Model Re-Parametrization + +Re-parametrization is widely used for such tasks as compact model design [29], neural architecture search [11, 63] + +
MethodFFHQPlaces2FLOPS (GFLOPS)Params (×106)
FID ↓LPIPS ↓FID ↓LPIPS ↓
LaMa32.710.25922.000.37832.0527.05
Co-Mod-GAN4.700.2579.320.39791.2179.17
SH-GAN4.330.2547.400.39291.2779.21
ZITS--16.780.356295.7278.49
MAT7.000.23114.380.394140.7459.78
LDM--13.400.3856,896.16387.25
HiFill--81.270.48818.142.72
MI-GAN (ours)4.990.25711.830.39411.195.95
+ +Table 1. Quantitative comparison of our method with state-of-the-art approaches on 256 resolution images. + +and pruning [14]. Inspired by recent work on online reparametrization [23], we adopt the technique to our architecture. We skip the linear scaling layer, instead we use weight normalizations described in [49]. We apply the reparametrization for all convolution layers in MI-GAN architecture. + +For a convolutional layer $L_{i}$ during training we define $n$ kernels $\omega_{i}^{1},\omega_{i}^{2},\ldots ,\omega_{i}^{n}\in \mathbb{R}^{C_{O}\times C_{I}\times k\times k}$ , where $C_O$ and $C_I$ are the numbers of output and input channels of $L_{i}$ respectively (for depthwise convolutions $C_I = 1$ regardless of input channel number of $L_{i}$ ), and $k$ is the kernel size. Then we initialize the kernels randomly from standard normal distribution, combine them via summation, and scale the result to have standard deviation equal to 1: + +$$ +\omega_ {i} = \frac {1}{\sqrt {n}} \sum_ {j = 1} ^ {n} \omega_ {i} ^ {j}. \tag {6} +$$ + +This follows by a weight normalization operation $\hat{\omega}_i = \frac{\omega_i}{\|\omega_i\|}$ . Finally $\hat{\omega}_i$ is being used as a convolutional (or depth-wise convolutional) kernel: + +$$ +L _ {i} (x) = \operatorname {C o n v} \left(x, \hat {\omega} _ {i}\right) + b _ {i}, \tag {7} +$$ + +where $b_{i}$ is the convolutional bias initialized with zeros. During inference all additional parameters are fused and $\hat{\omega}_{i}$ is directly applied in Eq. 7. + +Our re-parametrization for depthwise-separable convolution blocks is shown in Fig. 3. In our experiments we take $n = 9$ to somehow "compensate" and make the network's capacity close to the capacity of its teacher network. The impact of the re-parametrization trick is discussed in Sec. 4.6. + +# 4. Experiments + +# 4.1. Implementation Details + +Our experiments are conducted on Places2 [67] and FFHQ [27] datasets. Though our proposed model is fully convolutional, and can be used for inference on varying resolutions and aspect ratios, we create separate architectures for training on 256 and 512 resolution inputs. The purpose + +of having separate architectures is to minimize the FLOPS and the memory usage for higher resolution inputs. The architectural details of our models can be found in the supplementary material. + +To train our models on Places2 dataset we use Places365-Standard subset, which contains $\sim 1.8$ million images. All the metrics are calculated on Places2 validation set with 36,500 images. For 256 and 512 resolution models we train them for $\sim 950,000$ and $\sim 1,600,000$ iterations respectively. The training time for 256 and 512 resolution models was 23 days with 2 Nvidia Quadro-RTX 8000 GPUs and 30 days with 8 Nvidia A6000 GPUs respectively. + +We train the teacher Co-Mod-GAN model and our 256 resolution model on FFHQ by using randomly chosen 60,000 images, and evaluate all models on the rest 10,000 images. We train our model for $\sim 800$ , 000 iterations for 10 days with 8 Nvidia A6000 GPUs. + +Adam optimizer is used with learning rate 0.001 and with $\beta = (0,0.99)$ both for the generator and the discriminator. We fix batch size 32 for all experiments. + +# 4.2. Quantitative Comparison + +Tables 1 and 2 show comparison of our method with state-of-the-arts Co-Mod-GAN [65], SH-GAN [58], LaMa [53], LDM [46], ZITS [15], MAT [34] and HiFill [59] on Places2 and FFHQ datasets respectively. All the models besides Co-Mod-GAN are taken from their official repositories or are kindly provided by the corresponding authors. For Co-Mod-GAN we re-implemented it in PyTorch [43], and trained and tested the replicated version. The FID [21] scores of the replicated Co-Mod-GAN match the FID scores in the original paper. + +For the purpose of metric calculation we do the inference of all models in comparison using the free-form mask generation strategy as in Co-Mod-GAN [65]. The mask generation process combines multiple brush strokes and rectangles. The number of brush strokes is chosen randomly between 0 and 20. The widths of the brush strokes are chosen uniformly from the range (12, 40). Generated masks contain between 0 to 5 random rectangles up to the image size, and between 0 to 10 rectangles having maximum side fixed to the half of the image size. With this method of mask generation, masked area ratio varies between 0 and 1. + +We use Fréchet Inception Distance (FID) [21] as our primary metric. Also, we provide a comparison in terms of the perceptual metric LPIPS [64]. To show the computational complexity of the models we provide the number of floating point operations per second (FLOPS) and for the size of the models we report the number of model parameters. + +As can be noticed from Table 1, on Places2 dataset our model outperforms LaMa, ZITS, MAT and HiFill in terms of FID and is comparable with LDM, while slightly underperforms Co-Mod-GAN and SH-GAN being on par with + +![](images/c04b20684672c0b18ab8b1aea6a3cc5a26bf874a914e89987a03c3bb428d31dc.jpg) +Figure 4. Qualitative results of our model and other state of the art approaches on 256 resolution Places 2 samples with free-form masks. + +![](images/b056ed060704f5630f70acb7f226a9424ef4cc5286e6b174126c9aed0beca076.jpg) +Figure 5. Example results of our 512 resolution model and other state of the art approaches on 512 resolution Places2 test samples using free-form and user masks. Please zoom for a better view. + +them in terms of the perceptual metric LPIPS. However MI-GAN is almost 8 times faster and 13 times lighter than Co-Mod-GAN and SH-GAN. This emphasizes a great generative ability of MI-GAN while being a compact model designed for mobile devices. Let us notice that LDM and MAT does not provide a model working on 256 resolution, so to inference on 256 resolution we resize images to 512, process them with 512 models and then resize back to 256. On FFHQ we can observe a similar picture, while our + +method is even closer to Co-Mod-GAN and SH-GAN (i.e. has similar generative ability). For LaMa to inference on FFHQ dataset we have used the model trained on CelebA [38] dataset. LDM, ZITS and HiFill do not provide an inpainting model trained on faces. + +For the image resolution 512 MI-GAN performs similarly to LaMa and ZITS in terms of FID and slightly underperforms Co-Mod-GAN, SH-GAN, LDM and MAT. Qualitative analysis performed in Sec. 4.3 shows that the small + +![](images/cc780c8b2cf23d7580435a4fff84b29874dabc46cc5086020dbd595fca6151c1.jpg) +(a) +(b) +Figure 6. (a) Total rating of each method based on our user study. (b) Visual examples from the user study. Please zoom-in for better view. + +![](images/5a1e1e2328bdd27e51edeafe367640183c05e628e74950c5f720fb57a8e6acae.jpg) + +![](images/84083b3c2083c5a2cfd67a30082fd93b5c06c5337e37b7930acbc3ef55529f61.jpg) + +![](images/20bb641f1a621da3f8f620c09c2239b8b930033a14d4c3c48312acd67d59a7e0.jpg) + +![](images/156349b80c320a16d8723bf41eaa8326a74ab812c93affaba930e50a2da761da.jpg) + +![](images/0757840a27195a38ff778b0a0b8040fa6f677ccc9310a5e14fb6dbdc77a13066.jpg) + +![](images/c9dc608fa77b43f570d1aa33405b0ba77b42e0053d3ad03eb72faadc0aa19a89.jpg) + +![](images/5bbd4da2ae55b1c72d7d5203136215fb692ed1672cc39b66aba0b75ae750da3f.jpg) +Figure 7. Qualitative results from our model and other approaches on FFHQ dataset samples. Please zoom for a better view. + +difference in terms of FID has a small impact on visual results. Instead, our model is more than 7.5 times faster and 4.5 times lighter than the mentioned state-of-the-art approaches (see Table 2). + +Notice that even though HiFill has less number of parameters compared to our approach, MI-GAN is computationally more efficient and significantly outperforms HiFill quantitatively both on 256 and 512 resolutions. The reason that our model is computationally more efficient is that MI-GAN is a single-stage fully convolutional network consisting of depthwise-separable convolutions, whereas HiFill uses regular convolutions on higher resolution features and has a costly attention mechanism in its refinement network. + +To show the effectiveness of our approach on different mask sizes, we provide FID comparisons with varying mask ratios in the appendix. Additionally, in order to further prove the robustness of our approach against other metrics, we also include a comparison in terms of PSNR, SSIM [55], P-IDS and U-IDS [65] metrics in the appendix. + +# 4.3. Qualitative Comparison + +In this subsection we discuss the qualitative advantages of our model over some state-of-the-art approaches. As illustrated in Fig. 4 our model produces semantically meaningful content, even if the input mask is large. Our model has a strong generative capability, and the results are sharp, + +
MethodFID ↓LPIPS ↓FLOPS (GFLOPS)Parameters (×106)
LaMa12.360.314128.0627.05
Co-Mod-GAN8.050.343121.0979.79
SH-GAN7.030.339121.1579.82
ZITS12.940.310666.9778.49
MAT8.670.339288.7861.56
LDM8.460.34227,581.56387.25
HiFill64.070.43872.122.72
MI-GAN (ours)10.000.34515.695.98
+ +Table 2. Quantitative comparison of our method with state-of-the-art approaches on 512 resolution images. + +while approaches like LaMa [53] and ZITS [15] produce blurry results on larger masks (see the 1st row of the figure as an example). Besides, as can be noticed from the qualitative comparison, on 256 resolution images our approach can perform better than the bigger and exceedingly computationally expensive model LDM [46]. + +On higher resolution images (see Fig. 5) our model still produces semantically meaningful results. Besides, our results don't have a color inconsistency issue unlike LDM, LaMa and ZITS results (see the 1st row of the figure as an exemple). + +We also conduct a qualitative comparison on face images (see Fig. 7). On face images our model's results are on par with Co-Mod-GAN and SH-GAN, while being better than LaMa and MAT. + +More qualitative results can be found in the supplementary material. + +# 4.4. User Study + +In addition to comparing our MI-GAN model with SOTA inpainting methods, we conduct a user study against 5 built-in commercial mobile image inpainting apps. For this, we select a diverse set of 20 real world photos from OpenImages [30] dataset with varying resolutions and, using each method in comparison, carefully mask and remove predetermined objects from each photo. Then, we ask 3 people to anonymously rate each of 5 results from 1 to 5 for each photo and sum the given ratings for each method (see Fig. 6.a). As can be seen from the diagram, our approach has a + +
Device Name256-resolution
MI-GAN speed (ms, mean/std)Co-Mod-GAN speed (ms, mean/std)
iPhone71030.25 / 13.374475.33 / 39.55
iPhoneX630.80 / 12.212746.00 / 28.84
iPad mini (5th gen)552.40 / 8.102686.17 / 41.41
iPhone14-pro-max296.00 / 1.351374.40 / 84.78
Galaxy Tab S7+686.17 / 12.36- / -
Samsung Galaxy S81476.40 / 5.98- / -
vivo Y122918.08 / 33.47- / -
+ +Table 3. The actual speed of our 256 model vs Co-Mod-GAN 256 model deployed on various mobile devices. The actual speed is measured in milliseconds, the means and the stds of the speed are presented for each mobile device. Some numbers are missing, since Co-Mod-GAN was providing an out of memory error. + +clear advantage over other methods. Fig. 6.b shows qualitative samples from user study, where our result has obvious advantage over commercial mobile apps. We include more results in the supplementary material. + +# 4.5. Actual Speed on Mobile Devices + +Besides calculating FLOPS we also measure actual speed of our method on real mobile devices and compare MI-GAN with Co-Mod-GAN. As can be noticed from Table 3 on 256 resolution inputs our method is more than 4 times faster on average than Co-Mod-GAN, which allows MI-GAN to be used in real-world applications on mobile devices. + +All models in Table 3 are using CPUs of mobile devices and are deployed by using the neural network framework ONNX [3]. Nothing special was conducted to optimize the speed or memory usage of MI-GAN on ONNX, so we believe MI-GAN can be further optimized in terms of speed or memory consumption (particularly running it on GPUs of mobile devices). The actual running times on 512 resolution images can be found in the supplementary material. + +# 4.6. Ablation Study + +In this subsection we show the impact of our re-parametrization trick and knowledge distillation loss function for MI-GAN 256 resolution model. Both are designed to close the generative performance gap between MI-GAN and a larger inpainting network. Table 4 shows the quantitative effect of both. Fig. 8 shows that by adding re-parametrization trick we increase the semantic understanding of the model to generate more meaningful results. Further, the knowledge distillation adds more generative ability. Although both modifications has positive impact, one can notice that re-parametrization trick improves the method drastically (see also Fig. 8). + +
MethodFID ↓LPIPS ↓
Baseline14.940.407
Baseline + Re-Param12.220.400
MI-GAN: Baseline + Re-Param + KD11.830.39
+ +Table 4. The effect of model re-parametrization and knowledge distillation on MI-GAN 256 resolution model. As can be noticed both have positive impact in terms of both metrics FID and LPIPS. + +![](images/e34987006d4348a46ad2d4666217a9882257d3677d8ec9cc95a747e9368e7b83.jpg) +Figure 8. Visual results of ablation study on model reparametrization and knowledge distillation. + +# 5. Limitations and Societal Impact + +Although our method has good generation abilities producing visually plausible results, similar to other state-of-the-art approaches it sometimes meets difficulties when reconstructing complex 3D structures. We hypothesize this can be later improved by guiding the network with more information about the 3D structure of the objects in images. For visual examples of MI-GAN's failure cases please see our supplementary material. + +Our work aims to make the creative image editing easier and accessible for everyone with their mobile devices. Similar to other deep learning based image editing approaches our method may have both positive and negative societal impact depending on its application. As a positive impact MI-GAN can help the users to restore old photos or remove unpleasant objects from their photos making them more aesthetic. On the negative side it can be used to misrepresent the reality by removing important facts from the images. We strongly believe and hope that our work will give more positive value to creative editing users than its potential negative societal impact. + +# 6. Conclusion + +In this paper we introduce MI-GAN, the first generative mobile image inpainting network. By using depthwise separable convolutions, model re-parametrization, and knowledge distillation, MI-GAN is able to produce high-quality results while having a low computational cost and a small number of parameters. Qualitative and quantitative comparisons show that MI-GAN is comparable or sometimes outperforms the current state-of-the-art approaches while being a way faster and smaller. + +# References + +[1] Angeline Aguinaldo, Ping-Yeh Chiang, Alex Gain, Ameya Patil, Kolten Pearson, and Soheil Feizi. Compressing gans using knowledge distillation. arXiv preprint arXiv:1902.00159, 2019. 2 +[2] Michael Ashikhmin. Synthesizing natural textures. In Proceedings of the 2001 symposium on Interactive 3D graphics, pages 217-226, 2001. 2 +[3] Junjie Bai, Fang Lu, Ke Zhang, et al. Onnx: Open neural network exchange. https://github.com/onnx/onnx, 2019.8 +[4] Connelly Barnes, Eli Shechtman, Adam Finkelstein, and Dan B Goldman. Patchmatch: A randomized correspondence algorithm for structural image editing. ACM Trans. Graph., 28(3):24, 2009. 2 +[5] Marcelo Bertalmio, Guillermo Sapiro, Vincent Caseles, and Coloma Ballester. Image inpainting. In Proceedings of the 27th annual conference on Computer graphics and interactive techniques, pages 417-424, 2000. 2 +[6] Marcelo Bertalmio, Luminita Vese, Guillermo Sapiro, and Stanley Osher. Simultaneous structure and texture image inpainting. IEEE transactions on image processing, 12(8):882-889, 2003. 2 +[7] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. arXiv preprint arXiv:1809.11096, 2018.3 +[8] Tony F Chan and Jianhong Shen. Nontexture inpainting by curvature-driven diffusions. Journal of visual communication and image representation, 12(4):436-449, 2001. 2 +[9] Ting-Yun Chang and Chi-Jen Lu. Tinygan: Distilling big-gan for conditional image generation. In Proceedings of the Asian Conference on Computer Vision, 2020. 2, 3 +[10] Hanting Chen, Yunhe Wang, Han Shu, Changyuan Wen, Chunjing Xu, Boxin Shi, Chao Xu, and Chang Xu. Distilling portable generative adversarial networks for image translation. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 3585-3592, 2020. 2 +[11] Shoufa Chen, Yunpeng Chen, Shuicheng Yan, and Jiashi Feng. Efficient differentiable neural architecture search with meta kernels. ArXiv, abs/1912.04749, 2019. 4 +[12] Yunjey Choi, Youngjung Uh, Jaejun Yoo, and Jung-Woo Ha. Stargan v2: Diverse image synthesis for multiple domains. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 8188-8197, 2020. 3 + +[13] Antonio Criminisi, Patrick Pérez, and Kentaro Toyama. Region filling and object removal by exemplar-based image inpainting. IEEE Transactions on image processing, 13(9):1200-1212, 2004. 2 +[14] Xiaohan Ding, Tianxiang Hao, Jianchao Tan, Ji Liu, Jungong Han, Yuchen Guo, and Guiguang Ding. Resrep: Lossless cnn pruning via decoupling remembering and forgetting. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4510-4520, 2021. 5 +[15] Qiaole Dong, Chenjie Cao, and Yanwei Fu. Incremental transformer structure enhanced image inpainting with masking positional encoding. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11358-11368, 2022. 2, 5, 7 +[16] Alexei A Efros and William T Freeman. Image quilting for texture synthesis and transfer. In Proceedings of the 28th annual conference on Computer graphics and interactive techniques, pages 341-346, 2001. 2 +[17] Alexei A Efros and Thomas K Leung. Texture synthesis by non-parametric sampling. In Proceedings of the seventh IEEE international conference on computer vision, volume 2, pages 1033-1038. IEEE, 1999. 2 +[18] ADVA Soft GmbH. Touchretouch. 1 +[19] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. Communications of the ACM, 63(11):139–144, 2020. 2 +[20] Paul Harrison. A non-hierarchical procedure for re-synthesis of complex textures. 2001. 2 +[21] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in neural information processing systems, 30, 2017. 5 +[22] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Advances in Neural Information Processing Systems, 33:6840-6851, 2020. 2 +[23] Mu Hu, Junyi Feng, Jiashen Hua, Baisheng Lai, Jianqiang Huang, Xiaojin Gong, and Xian-Sheng Hua. Online convolutional re-parameterization. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 568-577, 2022. 5 +[24] Adobe Inc. Photoshop express photo editor. 1 +[25] Picsart Inc. Picsart photo editor & video. 1 +[26] Paras Kapoor and Tien D. Bui. Tinystargan v2: Distilling stargan v2 for efficient diverse image synthesis for multiple domains. In BMVC, 2021. 2, 3 +[27] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In 2019 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4396-4405, 2019. 1, 3, 4, 5 +[28] Rolf Kohler, Christian Schuler, Bernhard Schölkopf, and Stefan Harmeling. Mask-specific inpainting with deep neural networks. In German conference on pattern recognition, pages 523-534. Springer, 2014. 2 + +[29] Alexander Kolesnikov, Alexey Dosovitskiy, Dirk Weissenborn, Georg Heigold, Jakob Uszkoreit, Lucas Beyer, Matthias Minderer, Mostafa Dehghani, Neil Houlsby, Sylvain Gelly, Thomas Unterthiner, and Xiaohua Zhai. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations (ICLR), 2021. 4 +[30] Alina Kuznetsova, Hassan Rom, Neil Alldrin, Jasper Uijlings, Ivan Krasin, Jordi Pont-Tuset, Shahab Kamali, Stefan Popov, Matteo Malloci, Alexander Kolesnikov, Tom Duerig, and Vittorio Ferrari. The open images dataset v4: Unified image classification, object detection, and visual relationship detection at scale. IJCV, 2020. 7 +[31] Vivek Kwatra, Arno Schödl, Irfan Essa, Greg Turk, and Aaron Bobick. Graphcut textures: Image and video synthesis using graph cuts. Acm transactions on graphics (tog), 22(3):277-286, 2003. 2 +[32] Anat Levin, Assaf Zomet, and Yair Weiss. Learning how to inpaint from global image statistics. In ICCV, volume 1, pages 305-312, 2003. 2 +[33] Jingyuan Li, Ning Wang, Lefei Zhang, Bo Du, and Dacheng Tao. Recurrent feature reasoning for image inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7760-7768, 2020. 2 +[34] Wenbo Li, Zhe Lin, Kun Zhou, Lu Qi, Yi Wang, and Jiaya Jia. Mat: Mask-aware transformer for large hole image inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10758-10768, 2022. 2, 5 +[35] Zeqi Li, Ruowei Jiang, and Parham Aarabi. Semantic relation preserving knowledge distillation for image-to-image translation. In European conference on computer vision, pages 648-663. Springer, 2020. 2 +[36] Guilin Liu, Fitsum A Reda, Kevin J Shih, Ting-Chun Wang, Andrew Tao, and Bryan Catanzaro. Image inpainting for irregular holes using partial convolutions. In Proceedings of the European conference on computer vision (ECCV), pages 85-100, 2018. 2 +[37] Yuchen Liu, Zhixin Shu, Yijun Li, Zhe Lin, Federico Peruzzi, and Sun-Yuan Kung. Content-aware gan compression. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12156-12166, 2021. 2, 3 +[38] Ziwei Liu, Ping Luo, Xiaogang Wang, and Xiaou Tang. Deep learning face attributes in the wild. In Proceedings of International Conference on Computer Vision (ICCV), December 2015. 2, 6 +[39] Google LLC. Snapseed. 1 +[40] Andreas Lugmayr, Martin Danelljan, Andres Romero, Fisher Yu, Radu Timofte, and Luc Van Gool. Repaint: Inpainting using denoising diffusion probabilistic models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11461-11471, 2022. 2 +[41] Lars Mescheder, Andreas Geiger, and Sebastian Nowozin. Which training methods for gans do actually converge? In International conference on machine learning, pages 3481-3490. PMLR, 2018. 4 + +[42] Shant Navasardyan and Marianna Ohanyan. The family of onion convolutions for image inpainting. International Journal of Computer Vision, pages 1-30, 2022. 2 +[43] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, Luca Antiga, Alban Desmaison, Andreas Kopf, Edward Yang, Zachary DeVito, Martin Raison, Alykhan Tejani, Sasank Chilamkurthy, Benoit Steiner, Lu Fang, Junjie Bai, and Soumith Chintala. Pytorch: An imperative style, high-performance deep learning library. In Advances in Neural Information Processing Systems 32, pages 8024-8035. Curran Associates, Inc., 2019. 5 +[44] Jimmy S Ren, Li Xu, Qiong Yan, and Wenxiu Sun. Shepard convolutional neural networks. Advances in neural information processing systems, 28, 2015. 2 +[45] Yuxi Ren, Jie Wu, Xuefeng Xiao, and Jianchao Yang. Online multi-granularity distillation for gan compression. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6793-6803, 2021. 2, 3 +[46] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684-10695, 2022. 2, 5, 7 +[47] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image computing and computer-assisted intervention, pages 234-241. Springer, 2015. 3 +[48] Chitwan Sahara, William Chan, Huiwen Chang, Chris Lee, Jonathan Ho, Tim Salimans, David Fleet, and Mohammad Norouzi. Palette: Image-to-image diffusion models. In ACM SIGGRAPH 2022 Conference Proceedings, pages 1-10, 2022. 2 +[49] Tim Salimans and Durk P Kingma. Weight normalization: A simple reparameterization to accelerate training of deep neural networks. Advances in neural information processing systems, 29, 2016. 5 +[50] Jianhong Shen and Tony F Chan. Mathematical models for local nontexture inpaintings. SIAM Journal on Applied Mathematics, 62(3):1019-1043, 2002. 2 +[51] L Sifre and S Mallat. Rigid-motion scattering for image classification [phd thesis]. Ecole Polytechnique, 2014. 3 +[52] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. arXiv preprint arXiv:2010.02502, 2020. 2 +[53] Roman Suvorov, Elizaveta Logacheva, Anton Mashikhin, Anastasia Remizova, Armenii Ashukha, Aleksei Silvestrov, Naejin Kong, Harshith Goka, Kiwoong Park, and Victor Lempitsky. Resolution-robust large mask inpainting with fourier convolutions. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 2149–2159, 2022. 2, 5, 7 +[54] Yuri Viazovetskyi, Vladimir Ivashkin, and Evgeny Kashin. Stylegan2 distillation for feed-forward image manipulation. In European conference on computer vision, pages 170-186. Springer, 2020. 2, 4 + +[55] Z. Wang, E.P. Simoncelli, and A.C. Bovik. Multiscale structural similarity for image quality assessment. In The Thirty-Seventh Asilomar Conference on Signals, Systems & Computers, 2003, volume 2, pages 1398-1402 Vol.2, 2003. 7 +[56] Li-Yi Wei and Marc Levoy. Fast texture synthesis using tree-structured vector quantization. In Proceedings of the 27th annual conference on Computer graphics and interactive techniques, pages 479–488, 2000. 2 +[57] Junyuan Xie, Linli Xu, and Enhong Chen. Image denoising and inpainting with deep neural networks. Advances in neural information processing systems, 25, 2012. 2 +[58] Xingqian Xu, Shant Navasardyan, Vahram Tadevosyan, Andranik Sargsyan, Yadong Mu, and Humphrey Shi. Image completion with heterogeneously filtered spectral hints. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, 2023. 2, 5 +[59] Zili Yi, Qiang Tang, Shekoofeh Azizi, Daesik Jang, and Zhan Xu. Contextual residual aggregation for ultra high-resolution image inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7508-7517, 2020. 2, 5 +[60] Jiahui Yu, Zhe Lin, Jamei Yang, Xiaohui Shen, Xin Lu, and Thomas S Huang. Free-form image inpainting with gated convolution. In Proceedings of the IEEE/CVF international conference on computer vision, pages 4471-4480, 2019. 2 +[61] Linfeng Zhang, Xin Chen, Runpei Dong, and Kaisheng Ma. Region-aware knowledge distillation for efficient image-to-image translation. arXiv preprint arXiv:2205.12451, 2022. 2 +[62] Linfeng Zhang, Xin Chen, Xiaobing Tu, Pengfei Wan, Ning Xu, and Kaisheng Ma. Wavelet knowledge distillation: Towards efficient image-to-image translation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12464-12474, 2022. 2, 3 +[63] Mingyang Zhang, Xinyi Yu, Jingtao Rong, Linlin Ou, and Feng Gao. Repnas: Searching for efficient re-parameterizing blocks. arXiv preprint arXiv:2109.03508, 2021. 4 +[64] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 586-595, 2018. 5 +[65] Shengyu Zhao, Jonathan Cui, Yilun Sheng, Yue Dong, Xiao Liang, Eric I Chang, and Yan Xu. Large scale image completion via co-modulated generative adversarial networks. In International Conference on Learning Representations (ICLR), 2021. 2, 3, 4, 5, 7 +[66] Haitian Zheng, Zhe Lin, Jingwan Lu, Scott Cohen, Eli Shechtman, Connelly Barnes, Jianming Zhang, Ning Xu, Sohrab Amirghodsi, and Jiebo Luo. Cm-gan: Image inpainting with cascaded modulation gan and object-aware training. arXiv preprint arXiv:2203.11947, 2022. 2 +[67] Bolei Zhou, Agata Lapedriza, Aditya Khosla, Aude Oliva, and Antonio Torralba. Places: A 10 million image database for scene recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 40(6):1452-1464, 2018. 1, 5 \ No newline at end of file diff --git a/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/images.zip b/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..24815a5232b08864b7367deac84479b1abf55725 --- /dev/null +++ b/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:1f443ae8ae276f4ddc74bd4b9cf5b794a474a0bbe66578cd61104404ddcab496 +size 949825 diff --git a/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/layout.json b/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..ecbcaee04a697a6682b318e0bf67a53398abaf9b --- /dev/null +++ b/2023/MI-GAN_ A Simple Baseline for Image Inpainting on Mobile Devices/layout.json @@ -0,0 +1,8492 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 84, + 103, + 510, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 84, + 103, + 510, + 121 + ], + "spans": [ + { + "bbox": [ + 84, + 103, + 510, + 121 + ], + "type": "text", + "content": "MI-GAN: A Simple Baseline for Image Inpainting on Mobile Devices" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 111, + 142, + 481, + 158 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 142, + 481, + 158 + ], + "spans": [ + { + "bbox": [ + 111, + 142, + 481, + 158 + ], + "type": "text", + "content": "Andranik Sargsyan1, Shant Navasardyan1, Xingqian Xu1,2, Humphrey Shi1,2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 159, + 159, + 434, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 159, + 159, + 434, + 171 + ], + "spans": [ + { + "bbox": [ + 159, + 159, + 434, + 171 + ], + "type": "text", + "content": "1Picsart AI Research (PAIR), 2SHI Labs @ Georgia Tech, Oregon & UIUC" + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 49, + 213, + 146, + 279 + ], + "blocks": [ + { + "bbox": [ + 49, + 213, + 146, + 279 + ], + "lines": [ + { + "bbox": [ + 49, + 213, + 146, + 279 + ], + "spans": [ + { + "bbox": [ + 49, + 213, + 146, + 279 + ], + "type": "image", + "image_path": "bb7f114aaaa5bbefa86f556e4e918b2e2aa20967b6a906441865aab834372745.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 49, + 279, + 146, + 346 + ], + "blocks": [ + { + "bbox": [ + 49, + 279, + 146, + 346 + ], + "lines": [ + { + "bbox": [ + 49, + 279, + 146, + 346 + ], + "spans": [ + { + "bbox": [ + 49, + 279, + 146, + 346 + ], + "type": "image", + "image_path": "d164b12f6472219fbe504753207c4b1de06f28efe3ecd28b8c4a6cba9ded6416.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 350, + 547, + 405 + ], + "lines": [ + { + "bbox": [ + 45, + 350, + 547, + 405 + ], + "spans": [ + { + "bbox": [ + 45, + 350, + 547, + 405 + ], + "type": "text", + "content": "Figure 1. The proposed approach can produce plausible results both on complex scene images as well as on face images. The scene image inputs are taken from the Places 2 [67] dataset and the face image input is from FFHQ [27] dataset. The bubble chart on the right shows the advantage of our network over state-of-the-art approaches. The size of the bubble signifies the relative number of parameters of each approach and the number inside of the bubble shows the absolute number of model parameters. Our approach achieves a low FID, while being one order of magnitude smaller and faster than recent SOTA approaches." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 147, + 213, + 263, + 279 + ], + "blocks": [ + { + "bbox": [ + 147, + 213, + 263, + 279 + ], + "lines": [ + { + "bbox": [ + 147, + 213, + 263, + 279 + ], + "spans": [ + { + "bbox": [ + 147, + 213, + 263, + 279 + ], + "type": "image", + "image_path": "c0b63dbc8b9bf868f66c6546977f827871e09d743224dad746c7ddcfde2c0dc5.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 147, + 279, + 263, + 346 + ], + "blocks": [ + { + "bbox": [ + 147, + 279, + 263, + 346 + ], + "lines": [ + { + "bbox": [ + 147, + 279, + 263, + 346 + ], + "spans": [ + { + "bbox": [ + 147, + 279, + 263, + 346 + ], + "type": "image", + "image_path": "91cec3edb59fd48ace1155d068b8240420028b6f710ca15b23eb4c8141329c5b.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 264, + 213, + 331, + 279 + ], + "blocks": [ + { + "bbox": [ + 264, + 213, + 331, + 279 + ], + "lines": [ + { + "bbox": [ + 264, + 213, + 331, + 279 + ], + "spans": [ + { + "bbox": [ + 264, + 213, + 331, + 279 + ], + "type": "image", + "image_path": "4b708583e9b5bb964222019fb8c6a00928ced8705384dabb79cca5e94ed7ae76.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 264, + 279, + 331, + 346 + ], + "blocks": [ + { + "bbox": [ + 264, + 279, + 331, + 346 + ], + "lines": [ + { + "bbox": [ + 264, + 279, + 331, + 346 + ], + "spans": [ + { + "bbox": [ + 264, + 279, + 331, + 346 + ], + "type": "image", + "image_path": "4dc6b2c7f714cd9b3140f35ec68dd5f656fcdf3fea890da7b31b8a2e3eda18c1.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 333, + 213, + 545, + 346 + ], + "blocks": [ + { + "bbox": [ + 333, + 213, + 545, + 346 + ], + "lines": [ + { + "bbox": [ + 333, + 213, + 545, + 346 + ], + "spans": [ + { + "bbox": [ + 333, + 213, + 545, + 346 + ], + "type": "image", + "image_path": "bb3d5645c9c902fb69dee7f881a042fdeb08dec6c747afad0bbabff5baa6c6cb.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 143, + 419, + 192, + 431 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 419, + 192, + 431 + ], + "spans": [ + { + "bbox": [ + 143, + 419, + 192, + 431 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 452, + 290, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 452, + 290, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 452, + 290, + 715 + ], + "type": "text", + "content": "In recent years, many deep learning based image inpainting methods have been developed by the research community. Some of those methods have shown impressive image completion abilities. Yet, to the best of our knowledge, there is no image inpainting model designed to run on mobile devices. In this paper we present a simple image inpainting baseline, Mobile Inpainting GAN (MI-GAN), which is approximately one order of magnitude computationally cheaper and smaller than existing state-of-the-art inpainting models, and can be efficiently deployed on mobile devices. Excessive quantitative and qualitative evaluations show that MI-GAN performs comparable or, in some cases, better than recent state-of-the-art approaches. Moreover, we perform a user study comparing MI-GAN results with results from several commercial mobile inpainting applications, which clearly shows the advantage of MI-GAN in comparison to existing apps. With the purpose of high quality and efficient inpainting, we utilize an effective combination of adversarial training, model reparametrization, and knowledge distillation. Our models and code are publicly available at https://github.com/Picsart-AI-Research/MI-GAN." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 454, + 386, + 467 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 454, + 386, + 467 + ], + "spans": [ + { + "bbox": [ + 306, + 454, + 386, + 467 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 474, + 545, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 474, + 545, + 533 + ], + "spans": [ + { + "bbox": [ + 304, + 474, + 545, + 533 + ], + "type": "text", + "content": "The task of image inpainting is to complete the missing regions in images in a realistic and visually plausible way. Image inpainting algorithms have found their applications in such problems as image restoration, removal of unwanted objects, etc." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 535, + 546, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 535, + 546, + 700 + ], + "spans": [ + { + "bbox": [ + 304, + 535, + 546, + 700 + ], + "type": "text", + "content": "Nowadays, in the era of fast evolving gadgets, particularly smartphones, image/video editing applications are growing furiously. The usage of mobile devices for making creative visual content by professionals as well as by consumers shows a great increasing tendency. A lot of mobile applications such as Photoshop Express [24], Picsart [25], Snapseed [39], TouchRetouch [18] empower the users to create awesome content utilizing AI-powered tools. One of the most popular such tools, object remover, allows its users to remove unwanted objects (e.g. watermarks, lines, people or random objects in the background, etc.) from their photos. So millions of users every day benefit from image inpainting technologies integrated in various mobile applications." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 317, + 702, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 702, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 317, + 702, + 545, + 715 + ], + "type": "text", + "content": "Current AI-based state-of-the-art inpainting algorithms" + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "7335" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": "such as Co-Mod-GAN [65], SH-GAN [58], LaMa [53], or LDM [46] include an inference of a heavyweight neural network, which is often not feasible to do on low-end mobile devices (see Tables 1, 2). Therefore the processing is being done on server-side resulting in dependency on Internet connection, speed, traffic and server usage costs for image editing companies." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 156, + 287, + 216 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 156, + 287, + 216 + ], + "spans": [ + { + "bbox": [ + 46, + 156, + 287, + 216 + ], + "type": "text", + "content": "To address this problem we propose a simple baseline for high-quality mobile image inpainting which is an order of magnitude lighter and computationally more efficient than current state-of-the-art neural networks while showing similar or sometimes even better performance (see Fig. 1)." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 216, + 286, + 357 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 216, + 286, + 357 + ], + "spans": [ + { + "bbox": [ + 46, + 216, + 286, + 357 + ], + "type": "text", + "content": "Motivated by the generative nature of the image completion problem we design MI-GAN, Mobile Inpainting Generative Adversarial Network, which benefits from a hybrid system consisting of adversarial training, model reparametrization, and knowledge distillation. Thanks to adversarial nature of the MI-GAN training, image completion results appear to be visually plausible without producing blurry regions and pattern-like artifacts. Model reparametrization further increases the output quality at no cost of efficiency. Finally, knowledge distillation by a stronger network also improves the generative ability of MI-GAN." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 360, + 286, + 395 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 360, + 286, + 395 + ], + "spans": [ + { + "bbox": [ + 47, + 360, + 286, + 395 + ], + "type": "text", + "content": "Due to excessive evaluations MI-GAN shows great performance in terms of both quantitative and qualitative comparison with existing state-of-the-art methods." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 59, + 396, + 250, + 406 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 396, + 250, + 406 + ], + "spans": [ + { + "bbox": [ + 59, + 396, + 250, + 406 + ], + "type": "text", + "content": "To summarize, our contributions are three-fold." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 59, + 412, + 286, + 580 + ], + "type": "list", + "angle": 0, + "index": 8, + "blocks": [ + { + "bbox": [ + 59, + 412, + 286, + 437 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 412, + 286, + 437 + ], + "spans": [ + { + "bbox": [ + 59, + 412, + 286, + 437 + ], + "type": "text", + "content": "- We propose MI-GAN, to the best of our knowledge the first mobile generative image inpainting network." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 59, + 444, + 286, + 491 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 444, + 286, + 491 + ], + "spans": [ + { + "bbox": [ + 59, + 444, + 286, + 491 + ], + "type": "text", + "content": "- We develop a customized knowledge distillation method that is suitable for our model and problem, as well as we implement a model re-parametrization strategy which enhances the quality of results." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 59, + 498, + 286, + 580 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 498, + 286, + 580 + ], + "spans": [ + { + "bbox": [ + 59, + 498, + 286, + 580 + ], + "type": "text", + "content": "- While being computationally more efficient and lighter than the existing state-of-the-art image completion approaches, MI-GAN produces similar or even better image inpainting results. Furthermore, in comparison to existing commercial mobile inpainting applications, MI-GAN results are generally rated higher by human evaluators." + } + ] + } + ], + "index": 7 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 47, + 591, + 133, + 604 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 591, + 133, + 604 + ], + "spans": [ + { + "bbox": [ + 47, + 591, + 133, + 604 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 611, + 194, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 611, + 194, + 624 + ], + "spans": [ + { + "bbox": [ + 47, + 611, + 194, + 624 + ], + "type": "text", + "content": "2.1. Image Inpainting Methods" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "type": "text", + "content": "The task of image inpainting was and is being actively investigated by researchers during past decades. Classical approaches use diffusion processes [5, 6, 50, 8, 32] or exemplar-based techniques [17, 56, 20, 2, 4, 16, 31, 13] for coherent image restoration and completion. Although the classical methods greatly recover textures and preserve image structures, they lack of semantic understanding of the" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 72, + 544, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 544, + 95 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 544, + 95 + ], + "type": "text", + "content": "image context. Hence learning-based approaches were developed and later improved." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 97, + 545, + 323 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 97, + 545, + 323 + ], + "spans": [ + { + "bbox": [ + 304, + 97, + 545, + 323 + ], + "type": "text", + "content": "Early deep learning papers on image inpainting were trying to fill small missing regions by image-to-image discriminative models [57, 28, 44, 36]. Later, by using generative adversarial networks (GANs) [19], researchers were able to reach extra-high quality in image inpainting task [60, 42, 59, 33, 65, 53, 58, 66]. Some papers [36, 60, 42] additionally design special convolution layers to efficiently use the information in the known region of deep features. RFR [33] suggests a recurrent feature reasoning module which utilizes correlations between neighboring pixels to fill the missing pixels. With their contextual residual aggregation mechanism Yi et al. [59] enables ultra-high resolution inpainting (up to 8K). Several methods [65, 58, 66] benefit from a strong generative model StyleGAN-v2 [54] and make adoptions to image inpainting task. [65] introduces co-modulation blocks conditioning StyleGAN-v2 modulated architecture with the input image. SH-GAN [58] introduces spectral hint units to generate high-frequency details." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 324, + 545, + 396 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 324, + 545, + 396 + ], + "spans": [ + { + "bbox": [ + 304, + 324, + 545, + 396 + ], + "type": "text", + "content": "By benefiting from the Fourier analysis, LaMa [53] uses Fourier convolutions and greatly improves inpainting of repetitive patterns. ZITS [15] improves over LaMa by introducing a structure restoration mechanism with transformers. MAT [34] combines the strengths of convolutional and transformer-based models for large-hole inpainting." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 397, + 545, + 540 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 397, + 545, + 540 + ], + "spans": [ + { + "bbox": [ + 304, + 397, + 545, + 540 + ], + "type": "text", + "content": "Recently, diffusion models [22, 52] were introduced and impacted the image inpainting task [46, 40, 48]. Palette [48] provides an image-conditioned diffusion model for image-to-image translation tasks, namely, colorization, inpainting/outpainting, and JPEG restoration. RePaint [40] adopts the unconditional pretrained Denoising Diffusion Probabilistic Model (DDPM) [22] for image inpainting task by guiding its backward process with inpainting masks. LDM [46] applies a diffusion process in its latent space which particularly allows conditioning on textual prompts, by so extending its image inpainting abilities to text guided completion." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 551, + 487, + 563 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 551, + 487, + 563 + ], + "spans": [ + { + "bbox": [ + 306, + 551, + 487, + 563 + ], + "type": "text", + "content": "2.2. Lightweight Generative Modeling" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "type": "text", + "content": "Although generative adversarial networks are able to create extremely high quality images often indistinguishable from reality with a naked eye, they require a tremendous amount of computations and memory consumption. For this purpose some methods [1, 10, 35, 9, 26, 45, 61, 62, 37] design lightweight generative models. [1] firstly applied the concept of knowledge distillation on GANs and showed incredible compression rates (e.g. 87:1 on CelebA [38]) while preserving the original quality. [10] utilizes the student discriminator in a triplet loss to enforce it benefit from teacher generated images also. In [35] the authors propose semantic preserving distillation loss for image-to" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "7336" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 47, + 70, + 541, + 329 + ], + "blocks": [ + { + "bbox": [ + 47, + 70, + 541, + 329 + ], + "lines": [ + { + "bbox": [ + 47, + 70, + 541, + 329 + ], + "spans": [ + { + "bbox": [ + 47, + 70, + 541, + 329 + ], + "type": "image", + "image_path": "7659809ef2490153e262f0eb228d0c0ce05731978583268bbcdbe07d4bc75dfa.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 334, + 548, + 401 + ], + "lines": [ + { + "bbox": [ + 46, + 334, + 548, + 401 + ], + "spans": [ + { + "bbox": [ + 46, + 334, + 548, + 401 + ], + "type": "text", + "content": "Figure 2. The overview of our method. The generator of MI-GAN consists of two branches: the main branch with a Unet like architecture and the painting branch. The main branch consists of a linear projection layer, depthwise separable convolutions, and bilinear resizing operations. The painting branch completes the missing region with layer-by-layer inpainting similar to the manual work of some experts. The training is conducted by using adversarial loss function and knowledge distillation. The discriminator is similar to the encoder of the main branch, having also residual connections and fully connected layers (more details can be found in supplementary material). As a teacher network in our experiments we take Co-Mod-GAN [65]. Please zoom in for better view." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 420, + 289, + 563 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 420, + 289, + 563 + ], + "spans": [ + { + "bbox": [ + 46, + 420, + 289, + 563 + ], + "type": "text", + "content": "image translation task to preserve the semantic relations between the teacher and the student features. TinyGAN [9] and TinyStarGAN-v2 [26] are distilling high-fidelity image generation networks BigGAN [7] and Stargan-v2 [12] respectively. [45] proposes a GAN compression method with a student discriminator-free online distillation scheme. Recently in [62] the authors introduce wavelet knowledge distillation to transfer the high-frequency detail generating information from the teacher generative model to the student. [37] proposes a content-aware compression paradigm, which leverages generated contents to guide the process of pruning and distillation." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 578, + 104, + 590 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 578, + 104, + 590 + ], + "spans": [ + { + "bbox": [ + 47, + 578, + 104, + 590 + ], + "type": "text", + "content": "3. Method" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 598, + 129, + 609 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 598, + 129, + 609 + ], + "spans": [ + { + "bbox": [ + 47, + 598, + 129, + 609 + ], + "type": "text", + "content": "3.1. Architecture" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "text", + "content": "We introduce a simple baseline for mobile image inpainting which benefits from a combination of adversarial learning, model re-parametrization, and knowledge distillation. Formally, given an input image " + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "inline_equation", + "content": "I_{orig} \\in \\mathbb{R}^{H \\times W \\times 3}" + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "text", + "content": " and a binary mask " + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "inline_equation", + "content": "M \\in \\{0,1\\}^{H \\times W}" + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "text", + "content": " indicating the known region with 1-values and the missing region with 0-values. MI-GAN takes the concatenated input " + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "inline_equation", + "content": "In = [I_{orig} \\odot M, M] \\in \\mathbb{R}^{H \\times W \\times 4}" + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "text", + "content": " and returns a completed image " + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "inline_equation", + "content": "I_c" + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "text", + "content": " which is fi" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 420, + 545, + 444 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 420, + 545, + 444 + ], + "spans": [ + { + "bbox": [ + 305, + 420, + 545, + 444 + ], + "type": "text", + "content": "nally composited with the original image by using the binary mask " + }, + { + "bbox": [ + 305, + 420, + 545, + 444 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 305, + 420, + 545, + 444 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 344, + 453, + 545, + 466 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 344, + 453, + 545, + 466 + ], + "spans": [ + { + "bbox": [ + 344, + 453, + 545, + 466 + ], + "type": "interline_equation", + "content": "I _ {\\text {c o m p o s}} = I _ {\\text {o r i g}} \\odot M + I _ {c} \\odot (1 - M). \\tag {1}", + "image_path": "a34d25ecc10c923e4784b24c4705997517e41e05d376053b099454edb7e68f85.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 474, + 499, + 486 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 474, + 499, + 486 + ], + "spans": [ + { + "bbox": [ + 305, + 474, + 499, + 486 + ], + "type": "text", + "content": "The overview of our method is shown in Fig. 2." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 487, + 545, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 487, + 545, + 605 + ], + "spans": [ + { + "bbox": [ + 304, + 487, + 545, + 605 + ], + "type": "text", + "content": "We design a generative adversarial network, the generator of which consists of two parts: a U-Net [47] like main branch utilizing depthwise separable convolution layers [51], and the painting branch imitating the inpainting process of experts. Being inspired by the architecture of StyleGAN [27], the concept of our painting branch is greatly aligned with the inpainting task. Indeed, similar to experts (artists), our painting branch paints the missing region iteratively layer-by-layer in the RGB-space starting from the overall structure and ending with the final result." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 605, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 546, + 713 + ], + "type": "text", + "content": "The main branch architecture of MI-GAN starts with a convolution layer to project the 4-channel input space to a higher 128 dimension. Then a fully-convolutional encoder+decoder, consisting of depthwise separable convolutions and bilinear resizing operations, is applied resulting in a tensor with dimensionality " + }, + { + "bbox": [ + 304, + 605, + 546, + 713 + ], + "type": "inline_equation", + "content": "H \\times W \\times 128" + }, + { + "bbox": [ + 304, + 605, + 546, + 713 + ], + "type": "text", + "content": ". All convolutional blocks are using the LeakyReLU activation. Inspired by StyleGAN, to generate high-frequency details, we also add a random noise component (with a learnable noise" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "7337" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 59, + 68, + 547, + 286 + ], + "blocks": [ + { + "bbox": [ + 59, + 68, + 547, + 286 + ], + "lines": [ + { + "bbox": [ + 59, + 68, + 547, + 286 + ], + "spans": [ + { + "bbox": [ + 59, + 68, + 547, + 286 + ], + "type": "image", + "image_path": "d8e69c3417c9470072454cf4fb2b47beb825397cbc42c352f4953b25a736ca64.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 289, + 546, + 334 + ], + "lines": [ + { + "bbox": [ + 46, + 289, + 546, + 334 + ], + "spans": [ + { + "bbox": [ + 46, + 289, + 546, + 334 + ], + "type": "text", + "content": "Figure 3. The structure of our depthwise separable convolution layers showing " + }, + { + "bbox": [ + 46, + 289, + 546, + 334 + ], + "type": "inline_equation", + "content": "(a)" + }, + { + "bbox": [ + 46, + 289, + 546, + 334 + ], + "type": "text", + "content": " the model re-parametrization during training and " + }, + { + "bbox": [ + 46, + 289, + 546, + 334 + ], + "type": "inline_equation", + "content": "(b)" + }, + { + "bbox": [ + 46, + 289, + 546, + 334 + ], + "type": "text", + "content": " the utilization of the fused weights during the inference. We apply bilinear resizing in the case when the depthwise separable convolution block changes its input resolution. In the case of both training and inference in each pointwise convolution layer a random noise with a trainable amplitude is applied." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "spans": [ + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "type": "text", + "content": "amplitude) to the pointwise convolution layers of the decoder of the main branch (see Fig. 3). The painting branch takes the intermediate tensors from the main branch decoder and \"paints\" them to the RGB-space with projection convolutional layers, resulting in images " + }, + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "type": "inline_equation", + "content": "x_{i} \\in \\mathbb{R}_{\\frac{H}{2^{i}} \\times \\frac{W}{2^{i}} \\times 3}^{\\frac{H}{2^{i}} \\times \\frac{W}{2^{i}} \\times 3}" + }, + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "type": "text", + "content": " for " + }, + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "type": "inline_equation", + "content": "i = 0,1,\\ldots,6" + }, + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "type": "text", + "content": ". Then, the final image " + }, + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "type": "inline_equation", + "content": "I_{c} \\in \\mathbb{R}^{H \\times W \\times 3}" + }, + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "type": "text", + "content": " is obtained by \"painting\" (adding) the images " + }, + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "type": "inline_equation", + "content": "x_{i}" + }, + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "type": "text", + "content": " as layers on top of each other: " + }, + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "type": "inline_equation", + "content": "\\hat{x}_6 = x_6" + }, + { + "bbox": [ + 46, + 353, + 289, + 452 + ], + "type": "text", + "content": "," + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 64, + 456, + 287, + 484 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 64, + 456, + 287, + 484 + ], + "spans": [ + { + "bbox": [ + 64, + 456, + 287, + 484 + ], + "type": "interline_equation", + "content": "\\begin{array}{c} \\hat {x} _ {i} = B i l i n e a r U p (\\hat {x} _ {i + 1}) + x _ {i}, i = 5, 4, \\dots , 0, \\\\ I _ {c} = \\hat {x} _ {0}, \\end{array} \\tag {2}", + "image_path": "8035bc24df6bf666c81b230731042f85b81079207c3cb14aa413a11a3c651efd.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 490, + 287, + 514 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 490, + 287, + 514 + ], + "spans": [ + { + "bbox": [ + 47, + 490, + 287, + 514 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 490, + 287, + 514 + ], + "type": "inline_equation", + "content": "BilinearUp" + }, + { + "bbox": [ + 47, + 490, + 287, + 514 + ], + "type": "text", + "content": " is the bilinear upsampling operation with scaling factor equal to 2." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 514, + 287, + 539 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 514, + 287, + 539 + ], + "spans": [ + { + "bbox": [ + 47, + 514, + 287, + 539 + ], + "type": "text", + "content": "After the painting branch returns the inpainted image " + }, + { + "bbox": [ + 47, + 514, + 287, + 539 + ], + "type": "inline_equation", + "content": "I_{c}" + }, + { + "bbox": [ + 47, + 514, + 287, + 539 + ], + "type": "text", + "content": ", we get the final result by using Eq. 1." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 544, + 111, + 557 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 544, + 111, + 557 + ], + "spans": [ + { + "bbox": [ + 47, + 544, + 111, + 557 + ], + "type": "text", + "content": "3.2. Training" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 563, + 287, + 682 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 563, + 287, + 682 + ], + "spans": [ + { + "bbox": [ + 47, + 563, + 287, + 682 + ], + "type": "text", + "content": "To train MI-GAN we use a combination of an adversarial and a knowledge distillation loss functions " + }, + { + "bbox": [ + 47, + 563, + 287, + 682 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{adv}" + }, + { + "bbox": [ + 47, + 563, + 287, + 682 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 563, + 287, + 682 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{KD}" + }, + { + "bbox": [ + 47, + 563, + 287, + 682 + ], + "type": "text", + "content": " respectively. For an adversarial training we borrow the discriminator architecture from StyleGAN [27] and replace convolutional layers with depthwise-separable convolutions. Also, similar to StyleGAN [27], we utilize a nonsaturating (with softplus non-linearity) loss function with " + }, + { + "bbox": [ + 47, + 563, + 287, + 682 + ], + "type": "inline_equation", + "content": "R_{1}" + }, + { + "bbox": [ + 47, + 563, + 287, + 682 + ], + "type": "text", + "content": "-regularization [41] for discriminator training. For the generator MI-GAN the adversarial component of the loss function will accordingly be as follows:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 55, + 689, + 287, + 714 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 689, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 55, + 689, + 287, + 714 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {a d v} = \\mathbb {E} _ {x, m \\sim P _ {c, m}} [ S o f t P l u s (- D _ {w} (G _ {\\theta} (x, m), m)) ], \\tag {3}", + "image_path": "9d66e1e655874b58c130c4b5918b4d53b11e22cf9b0ca30f7aad0a0afd3ed763.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 353, + 545, + 399 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 353, + 545, + 399 + ], + "spans": [ + { + "bbox": [ + 304, + 353, + 545, + 399 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 353, + 545, + 399 + ], + "type": "inline_equation", + "content": "P_{c,m}" + }, + { + "bbox": [ + 304, + 353, + 545, + 399 + ], + "type": "text", + "content": " is the joint distribution of corrupted images (which should be inpainted) and the corresponding missing regions, " + }, + { + "bbox": [ + 304, + 353, + 545, + 399 + ], + "type": "inline_equation", + "content": "D_w" + }, + { + "bbox": [ + 304, + 353, + 545, + 399 + ], + "type": "text", + "content": " is the discriminator, and " + }, + { + "bbox": [ + 304, + 353, + 545, + 399 + ], + "type": "inline_equation", + "content": "G_{\\theta}" + }, + { + "bbox": [ + 304, + 353, + 545, + 399 + ], + "type": "text", + "content": " is the generator, i.e. our MI-GAN." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 400, + 546, + 484 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 400, + 546, + 484 + ], + "spans": [ + { + "bbox": [ + 304, + 400, + 546, + 484 + ], + "type": "text", + "content": "For a knowledge distillation we choose Co-Mod-GAN [65] as a teacher network for MI-GAN due to its strong generative ability inherited from StyleGAN-v2 [54]. Similar to us, inspired by StyleGAN, Co-Mod-GAN also has a painting branch. Hence we put a knowledge-distillation loss between the inpainted regions of intermediate results of the painting branches of Co-Mod-GAN and MI-GAN:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 346, + 490, + 545, + 522 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 346, + 490, + 545, + 522 + ], + "spans": [ + { + "bbox": [ + 346, + 490, + 545, + 522 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {K D} = \\sum_ {i = 0} ^ {3} \\| \\left(x _ {i} - x _ {i} ^ {C}\\right) \\odot (1 - M _ {i}) \\|, \\tag {4}", + "image_path": "9aa90ac9302de08916a55e2663a517facbb478ee219531ce7e76e06837d1e07c.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "spans": [ + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "type": "inline_equation", + "content": "x_{i}" + }, + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "type": "inline_equation", + "content": "x_{i}^{C}" + }, + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "type": "text", + "content": " are the intermediate results of painting branches of MI-GAN and Co-Mod-GAN respectively, and " + }, + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "type": "inline_equation", + "content": "M_{i} \\in \\{0,1\\}^{\\frac{H}{2^{i}} \\times \\frac{W}{2^{i}}}" + }, + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "type": "text", + "content": " is obtained by resizing the binary mask " + }, + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "type": "text", + "content": " to the size of " + }, + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "type": "inline_equation", + "content": "x_{i}" + }, + { + "bbox": [ + 304, + 529, + 545, + 601 + ], + "type": "text", + "content": " (with the nearest neighbour interpolation). In Sec. 4.6 we discuss the effect of knowledge distillation loss." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 603, + 545, + 627 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 603, + 545, + 627 + ], + "spans": [ + { + "bbox": [ + 304, + 603, + 545, + 627 + ], + "type": "text", + "content": "So the final loss function for MI-GAN generator will be the weighted combination" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 375, + 634, + 545, + 647 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 375, + 634, + 545, + 647 + ], + "spans": [ + { + "bbox": [ + 375, + 634, + 545, + 647 + ], + "type": "interline_equation", + "content": "\\mathcal {L} = \\lambda_ {1} \\mathcal {L} _ {a d v} + \\lambda_ {2} \\mathcal {L} _ {K D}. \\tag {5}", + "image_path": "19c5d3b512b1ac91720abe68c06ee451f2c3346ff248e50bba70ee5f2bebca03.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 653, + 484, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 653, + 484, + 665 + ], + "spans": [ + { + "bbox": [ + 306, + 653, + 484, + 665 + ], + "type": "text", + "content": "In our experiments we take " + }, + { + "bbox": [ + 306, + 653, + 484, + 665 + ], + "type": "inline_equation", + "content": "\\lambda_1 = 1, \\lambda_2 = 2" + }, + { + "bbox": [ + 306, + 653, + 484, + 665 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 671, + 454, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 671, + 454, + 682 + ], + "spans": [ + { + "bbox": [ + 306, + 671, + 454, + 682 + ], + "type": "text", + "content": "3.3. Model Re-Parametrization" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 305, + 689, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 545, + 714 + ], + "type": "text", + "content": "Re-parametrization is widely used for such tasks as compact model design [29], neural architecture search [11, 63]" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "7338" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 70, + 288, + 168 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 288, + 168 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 288, + 168 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 288, + 168 + ], + "type": "table", + "html": "
MethodFFHQPlaces2FLOPS (GFLOPS)Params (×106)
FID ↓LPIPS ↓FID ↓LPIPS ↓
LaMa32.710.25922.000.37832.0527.05
Co-Mod-GAN4.700.2579.320.39791.2179.17
SH-GAN4.330.2547.400.39291.2779.21
ZITS--16.780.356295.7278.49
MAT7.000.23114.380.394140.7459.78
LDM--13.400.3856,896.16387.25
HiFill--81.270.48818.142.72
MI-GAN (ours)4.990.25711.830.39411.195.95
", + "image_path": "945476dd65c53568bb26e505292dbecb6bcdbfda365c3533e28432c536c06540.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 173, + 287, + 196 + ], + "lines": [ + { + "bbox": [ + 47, + 173, + 287, + 196 + ], + "spans": [ + { + "bbox": [ + 47, + 173, + 287, + 196 + ], + "type": "text", + "content": "Table 1. Quantitative comparison of our method with state-of-the-art approaches on 256 resolution images." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 214, + 287, + 285 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 214, + 287, + 285 + ], + "spans": [ + { + "bbox": [ + 46, + 214, + 287, + 285 + ], + "type": "text", + "content": "and pruning [14]. Inspired by recent work on online reparametrization [23], we adopt the technique to our architecture. We skip the linear scaling layer, instead we use weight normalizations described in [49]. We apply the reparametrization for all convolution layers in MI-GAN architecture." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "spans": [ + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "text", + "content": "For a convolutional layer " + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "inline_equation", + "content": "L_{i}" + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "text", + "content": " during training we define " + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "text", + "content": " kernels " + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "inline_equation", + "content": "\\omega_{i}^{1},\\omega_{i}^{2},\\ldots ,\\omega_{i}^{n}\\in \\mathbb{R}^{C_{O}\\times C_{I}\\times k\\times k}" + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "inline_equation", + "content": "C_O" + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "inline_equation", + "content": "C_I" + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "text", + "content": " are the numbers of output and input channels of " + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "inline_equation", + "content": "L_{i}" + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "text", + "content": " respectively (for depthwise convolutions " + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "inline_equation", + "content": "C_I = 1" + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "text", + "content": " regardless of input channel number of " + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "inline_equation", + "content": "L_{i}" + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "text", + "content": "), and " + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 46, + 286, + 287, + 382 + ], + "type": "text", + "content": " is the kernel size. Then we initialize the kernels randomly from standard normal distribution, combine them via summation, and scale the result to have standard deviation equal to 1:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 129, + 391, + 287, + 422 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 129, + 391, + 287, + 422 + ], + "spans": [ + { + "bbox": [ + 129, + 391, + 287, + 422 + ], + "type": "interline_equation", + "content": "\\omega_ {i} = \\frac {1}{\\sqrt {n}} \\sum_ {j = 1} ^ {n} \\omega_ {i} ^ {j}. \\tag {6}", + "image_path": "ca583e04c02ea4c0473467a6c4c37854557b198aed356c78b5657bbe36fb1026.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 430, + 287, + 467 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 430, + 287, + 467 + ], + "spans": [ + { + "bbox": [ + 47, + 430, + 287, + 467 + ], + "type": "text", + "content": "This follows by a weight normalization operation " + }, + { + "bbox": [ + 47, + 430, + 287, + 467 + ], + "type": "inline_equation", + "content": "\\hat{\\omega}_i = \\frac{\\omega_i}{\\|\\omega_i\\|}" + }, + { + "bbox": [ + 47, + 430, + 287, + 467 + ], + "type": "text", + "content": ". Finally " + }, + { + "bbox": [ + 47, + 430, + 287, + 467 + ], + "type": "inline_equation", + "content": "\\hat{\\omega}_i" + }, + { + "bbox": [ + 47, + 430, + 287, + 467 + ], + "type": "text", + "content": " is being used as a convolutional (or depth-wise convolutional) kernel:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 110, + 476, + 287, + 490 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 476, + 287, + 490 + ], + "spans": [ + { + "bbox": [ + 110, + 476, + 287, + 490 + ], + "type": "interline_equation", + "content": "L _ {i} (x) = \\operatorname {C o n v} \\left(x, \\hat {\\omega} _ {i}\\right) + b _ {i}, \\tag {7}", + "image_path": "39c09046fdeb8d4cebae63127f76e11c01d5cb43fc50338e882937712ad799b1.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 497, + 286, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 497, + 286, + 533 + ], + "spans": [ + { + "bbox": [ + 46, + 497, + 286, + 533 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 497, + 286, + 533 + ], + "type": "inline_equation", + "content": "b_{i}" + }, + { + "bbox": [ + 46, + 497, + 286, + 533 + ], + "type": "text", + "content": " is the convolutional bias initialized with zeros. During inference all additional parameters are fused and " + }, + { + "bbox": [ + 46, + 497, + 286, + 533 + ], + "type": "inline_equation", + "content": "\\hat{\\omega}_{i}" + }, + { + "bbox": [ + 46, + 497, + 286, + 533 + ], + "type": "text", + "content": " is directly applied in Eq. 7." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 533, + 287, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 533, + 287, + 604 + ], + "spans": [ + { + "bbox": [ + 46, + 533, + 287, + 604 + ], + "type": "text", + "content": "Our re-parametrization for depthwise-separable convolution blocks is shown in Fig. 3. In our experiments we take " + }, + { + "bbox": [ + 46, + 533, + 287, + 604 + ], + "type": "inline_equation", + "content": "n = 9" + }, + { + "bbox": [ + 46, + 533, + 287, + 604 + ], + "type": "text", + "content": " to somehow \"compensate\" and make the network's capacity close to the capacity of its teacher network. The impact of the re-parametrization trick is discussed in Sec. 4.6." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 616, + 128, + 628 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 616, + 128, + 628 + ], + "spans": [ + { + "bbox": [ + 47, + 616, + 128, + 628 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 635, + 180, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 635, + 180, + 647 + ], + "spans": [ + { + "bbox": [ + 47, + 635, + 180, + 647 + ], + "type": "text", + "content": "4.1. Implementation Details" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "type": "text", + "content": "Our experiments are conducted on Places2 [67] and FFHQ [27] datasets. Though our proposed model is fully convolutional, and can be used for inference on varying resolutions and aspect ratios, we create separate architectures for training on 256 and 512 resolution inputs. The purpose" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 72, + 545, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 120 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 120 + ], + "type": "text", + "content": "of having separate architectures is to minimize the FLOPS and the memory usage for higher resolution inputs. The architectural details of our models can be found in the supplementary material." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 121, + 546, + 216 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 121, + 546, + 216 + ], + "spans": [ + { + "bbox": [ + 304, + 121, + 546, + 216 + ], + "type": "text", + "content": "To train our models on Places2 dataset we use Places365-Standard subset, which contains " + }, + { + "bbox": [ + 304, + 121, + 546, + 216 + ], + "type": "inline_equation", + "content": "\\sim 1.8" + }, + { + "bbox": [ + 304, + 121, + 546, + 216 + ], + "type": "text", + "content": " million images. All the metrics are calculated on Places2 validation set with 36,500 images. For 256 and 512 resolution models we train them for " + }, + { + "bbox": [ + 304, + 121, + 546, + 216 + ], + "type": "inline_equation", + "content": "\\sim 950,000" + }, + { + "bbox": [ + 304, + 121, + 546, + 216 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 121, + 546, + 216 + ], + "type": "inline_equation", + "content": "\\sim 1,600,000" + }, + { + "bbox": [ + 304, + 121, + 546, + 216 + ], + "type": "text", + "content": " iterations respectively. The training time for 256 and 512 resolution models was 23 days with 2 Nvidia Quadro-RTX 8000 GPUs and 30 days with 8 Nvidia A6000 GPUs respectively." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 217, + 545, + 276 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 217, + 545, + 276 + ], + "spans": [ + { + "bbox": [ + 304, + 217, + 545, + 276 + ], + "type": "text", + "content": "We train the teacher Co-Mod-GAN model and our 256 resolution model on FFHQ by using randomly chosen 60,000 images, and evaluate all models on the rest 10,000 images. We train our model for " + }, + { + "bbox": [ + 304, + 217, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\sim 800" + }, + { + "bbox": [ + 304, + 217, + 545, + 276 + ], + "type": "text", + "content": ", 000 iterations for 10 days with 8 Nvidia A6000 GPUs." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 277, + 545, + 313 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 277, + 545, + 313 + ], + "spans": [ + { + "bbox": [ + 304, + 277, + 545, + 313 + ], + "type": "text", + "content": "Adam optimizer is used with learning rate 0.001 and with " + }, + { + "bbox": [ + 304, + 277, + 545, + 313 + ], + "type": "inline_equation", + "content": "\\beta = (0,0.99)" + }, + { + "bbox": [ + 304, + 277, + 545, + 313 + ], + "type": "text", + "content": " both for the generator and the discriminator. We fix batch size 32 for all experiments." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 322, + 448, + 335 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 322, + 448, + 335 + ], + "spans": [ + { + "bbox": [ + 306, + 322, + 448, + 335 + ], + "type": "text", + "content": "4.2. Quantitative Comparison" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 341, + 545, + 461 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 341, + 545, + 461 + ], + "spans": [ + { + "bbox": [ + 304, + 341, + 545, + 461 + ], + "type": "text", + "content": "Tables 1 and 2 show comparison of our method with state-of-the-arts Co-Mod-GAN [65], SH-GAN [58], LaMa [53], LDM [46], ZITS [15], MAT [34] and HiFill [59] on Places2 and FFHQ datasets respectively. All the models besides Co-Mod-GAN are taken from their official repositories or are kindly provided by the corresponding authors. For Co-Mod-GAN we re-implemented it in PyTorch [43], and trained and tested the replicated version. The FID [21] scores of the replicated Co-Mod-GAN match the FID scores in the original paper." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 461, + 545, + 592 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 461, + 545, + 592 + ], + "spans": [ + { + "bbox": [ + 304, + 461, + 545, + 592 + ], + "type": "text", + "content": "For the purpose of metric calculation we do the inference of all models in comparison using the free-form mask generation strategy as in Co-Mod-GAN [65]. The mask generation process combines multiple brush strokes and rectangles. The number of brush strokes is chosen randomly between 0 and 20. The widths of the brush strokes are chosen uniformly from the range (12, 40). Generated masks contain between 0 to 5 random rectangles up to the image size, and between 0 to 10 rectangles having maximum side fixed to the half of the image size. With this method of mask generation, masked area ratio varies between 0 and 1." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 594, + 545, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 545, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 545, + 665 + ], + "type": "text", + "content": "We use Fréchet Inception Distance (FID) [21] as our primary metric. Also, we provide a comparison in terms of the perceptual metric LPIPS [64]. To show the computational complexity of the models we provide the number of floating point operations per second (FLOPS) and for the size of the models we report the number of model parameters." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 665, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 714 + ], + "type": "text", + "content": "As can be noticed from Table 1, on Places2 dataset our model outperforms LaMa, ZITS, MAT and HiFill in terms of FID and is comparable with LDM, while slightly underperforms Co-Mod-GAN and SH-GAN being on par with" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "7339" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 47, + 69, + 545, + 358 + ], + "blocks": [ + { + "bbox": [ + 47, + 69, + 545, + 358 + ], + "lines": [ + { + "bbox": [ + 47, + 69, + 545, + 358 + ], + "spans": [ + { + "bbox": [ + 47, + 69, + 545, + 358 + ], + "type": "image", + "image_path": "c04b20684672c0b18ab8b1aea6a3cc5a26bf874a914e89987a03c3bb428d31dc.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 363, + 541, + 374 + ], + "lines": [ + { + "bbox": [ + 47, + 363, + 541, + 374 + ], + "spans": [ + { + "bbox": [ + 47, + 363, + 541, + 374 + ], + "type": "text", + "content": "Figure 4. Qualitative results of our model and other state of the art approaches on 256 resolution Places 2 samples with free-form masks." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 47, + 384, + 545, + 563 + ], + "blocks": [ + { + "bbox": [ + 47, + 384, + 545, + 563 + ], + "lines": [ + { + "bbox": [ + 47, + 384, + 545, + 563 + ], + "spans": [ + { + "bbox": [ + 47, + 384, + 545, + 563 + ], + "type": "image", + "image_path": "b056ed060704f5630f70acb7f226a9424ef4cc5286e6b174126c9aed0beca076.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 565, + 546, + 586 + ], + "lines": [ + { + "bbox": [ + 47, + 565, + 546, + 586 + ], + "spans": [ + { + "bbox": [ + 47, + 565, + 546, + 586 + ], + "type": "text", + "content": "Figure 5. Example results of our 512 resolution model and other state of the art approaches on 512 resolution Places2 test samples using free-form and user masks. Please zoom for a better view." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 605, + 289, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 289, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 289, + 713 + ], + "type": "text", + "content": "them in terms of the perceptual metric LPIPS. However MI-GAN is almost 8 times faster and 13 times lighter than Co-Mod-GAN and SH-GAN. This emphasizes a great generative ability of MI-GAN while being a compact model designed for mobile devices. Let us notice that LDM and MAT does not provide a model working on 256 resolution, so to inference on 256 resolution we resize images to 512, process them with 512 models and then resize back to 256. On FFHQ we can observe a similar picture, while our" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 605, + 545, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 545, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 545, + 665 + ], + "type": "text", + "content": "method is even closer to Co-Mod-GAN and SH-GAN (i.e. has similar generative ability). For LaMa to inference on FFHQ dataset we have used the model trained on CelebA [38] dataset. LDM, ZITS and HiFill do not provide an inpainting model trained on faces." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 665, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 546, + 713 + ], + "type": "text", + "content": "For the image resolution 512 MI-GAN performs similarly to LaMa and ZITS in terms of FID and slightly underperforms Co-Mod-GAN, SH-GAN, LDM and MAT. Qualitative analysis performed in Sec. 4.3 shows that the small" + } + ] + } + ], + "index": 6 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "7340" + } + ] + } + ], + "index": 7 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 59, + 71, + 174, + 153 + ], + "blocks": [ + { + "bbox": [ + 50, + 105, + 60, + 113 + ], + "lines": [ + { + "bbox": [ + 50, + 105, + 60, + 113 + ], + "spans": [ + { + "bbox": [ + 50, + 105, + 60, + 113 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 59, + 71, + 174, + 153 + ], + "lines": [ + { + "bbox": [ + 59, + 71, + 174, + 153 + ], + "spans": [ + { + "bbox": [ + 59, + 71, + 174, + 153 + ], + "type": "image", + "image_path": "cc780c8b2cf23d7580435a4fff84b29874dabc46cc5086020dbd595fca6151c1.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 175, + 105, + 185, + 112 + ], + "lines": [ + { + "bbox": [ + 175, + 105, + 185, + 112 + ], + "spans": [ + { + "bbox": [ + 175, + 105, + 185, + 112 + ], + "type": "text", + "content": "(b)" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 47, + 157, + 545, + 168 + ], + "lines": [ + { + "bbox": [ + 47, + 157, + 545, + 168 + ], + "spans": [ + { + "bbox": [ + 47, + 157, + 545, + 168 + ], + "type": "text", + "content": "Figure 6. (a) Total rating of each method based on our user study. (b) Visual examples from the user study. Please zoom-in for better view." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 187, + 70, + 288, + 153 + ], + "blocks": [ + { + "bbox": [ + 187, + 70, + 288, + 153 + ], + "lines": [ + { + "bbox": [ + 187, + 70, + 288, + 153 + ], + "spans": [ + { + "bbox": [ + 187, + 70, + 288, + 153 + ], + "type": "image", + "image_path": "5a1e1e2328bdd27e51edeafe367640183c05e628e74950c5f720fb57a8e6acae.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 290, + 70, + 340, + 153 + ], + "blocks": [ + { + "bbox": [ + 290, + 70, + 340, + 153 + ], + "lines": [ + { + "bbox": [ + 290, + 70, + 340, + 153 + ], + "spans": [ + { + "bbox": [ + 290, + 70, + 340, + 153 + ], + "type": "image", + "image_path": "84083b3c2083c5a2cfd67a30082fd93b5c06c5337e37b7930acbc3ef55529f61.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 340, + 70, + 391, + 153 + ], + "blocks": [ + { + "bbox": [ + 340, + 70, + 391, + 153 + ], + "lines": [ + { + "bbox": [ + 340, + 70, + 391, + 153 + ], + "spans": [ + { + "bbox": [ + 340, + 70, + 391, + 153 + ], + "type": "image", + "image_path": "20bb641f1a621da3f8f620c09c2239b8b930033a14d4c3c48312acd67d59a7e0.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 391, + 70, + 441, + 153 + ], + "blocks": [ + { + "bbox": [ + 391, + 70, + 441, + 153 + ], + "lines": [ + { + "bbox": [ + 391, + 70, + 441, + 153 + ], + "spans": [ + { + "bbox": [ + 391, + 70, + 441, + 153 + ], + "type": "image", + "image_path": "156349b80c320a16d8723bf41eaa8326a74ab812c93affaba930e50a2da761da.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 442, + 70, + 492, + 153 + ], + "blocks": [ + { + "bbox": [ + 442, + 70, + 492, + 153 + ], + "lines": [ + { + "bbox": [ + 442, + 70, + 492, + 153 + ], + "spans": [ + { + "bbox": [ + 442, + 70, + 492, + 153 + ], + "type": "image", + "image_path": "0757840a27195a38ff778b0a0b8040fa6f677ccc9310a5e14fb6dbdc77a13066.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 493, + 70, + 545, + 153 + ], + "blocks": [ + { + "bbox": [ + 493, + 70, + 545, + 153 + ], + "lines": [ + { + "bbox": [ + 493, + 70, + 545, + 153 + ], + "spans": [ + { + "bbox": [ + 493, + 70, + 545, + 153 + ], + "type": "image", + "image_path": "c9dc608fa77b43f570d1aa33405b0ba77b42e0053d3ad03eb72faadc0aa19a89.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 50, + 186, + 286, + 355 + ], + "blocks": [ + { + "bbox": [ + 50, + 186, + 286, + 355 + ], + "lines": [ + { + "bbox": [ + 50, + 186, + 286, + 355 + ], + "spans": [ + { + "bbox": [ + 50, + 186, + 286, + 355 + ], + "type": "image", + "image_path": "5bbd4da2ae55b1c72d7d5203136215fb692ed1672cc39b66aba0b75ae750da3f.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 357, + 286, + 380 + ], + "lines": [ + { + "bbox": [ + 47, + 357, + 286, + 380 + ], + "spans": [ + { + "bbox": [ + 47, + 357, + 286, + 380 + ], + "type": "text", + "content": "Figure 7. Qualitative results from our model and other approaches on FFHQ dataset samples. Please zoom for a better view." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 400, + 286, + 448 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 400, + 286, + 448 + ], + "spans": [ + { + "bbox": [ + 46, + 400, + 286, + 448 + ], + "type": "text", + "content": "difference in terms of FID has a small impact on visual results. Instead, our model is more than 7.5 times faster and 4.5 times lighter than the mentioned state-of-the-art approaches (see Table 2)." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 449, + 286, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 449, + 286, + 555 + ], + "spans": [ + { + "bbox": [ + 46, + 449, + 286, + 555 + ], + "type": "text", + "content": "Notice that even though HiFill has less number of parameters compared to our approach, MI-GAN is computationally more efficient and significantly outperforms HiFill quantitatively both on 256 and 512 resolutions. The reason that our model is computationally more efficient is that MI-GAN is a single-stage fully convolutional network consisting of depthwise-separable convolutions, whereas HiFill uses regular convolutions on higher resolution features and has a costly attention mechanism in its refinement network." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 555, + 286, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 555, + 286, + 628 + ], + "spans": [ + { + "bbox": [ + 46, + 555, + 286, + 628 + ], + "type": "text", + "content": "To show the effectiveness of our approach on different mask sizes, we provide FID comparisons with varying mask ratios in the appendix. Additionally, in order to further prove the robustness of our approach against other metrics, we also include a comparison in terms of PSNR, SSIM [55], P-IDS and U-IDS [65] metrics in the appendix." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 47, + 635, + 182, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 635, + 182, + 647 + ], + "spans": [ + { + "bbox": [ + 47, + 635, + 182, + 647 + ], + "type": "text", + "content": "4.3. Qualitative Comparison" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 46, + 654, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 654, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 654, + 286, + 713 + ], + "type": "text", + "content": "In this subsection we discuss the qualitative advantages of our model over some state-of-the-art approaches. As illustrated in Fig. 4 our model produces semantically meaningful content, even if the input mask is large. Our model has a strong generative capability, and the results are sharp," + } + ] + } + ], + "index": 16 + }, + { + "type": "table", + "bbox": [ + 309, + 186, + 545, + 308 + ], + "blocks": [ + { + "bbox": [ + 309, + 186, + 545, + 308 + ], + "lines": [ + { + "bbox": [ + 309, + 186, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 309, + 186, + 545, + 308 + ], + "type": "table", + "html": "
MethodFID ↓LPIPS ↓FLOPS (GFLOPS)Parameters (×106)
LaMa12.360.314128.0627.05
Co-Mod-GAN8.050.343121.0979.79
SH-GAN7.030.339121.1579.82
ZITS12.940.310666.9778.49
MAT8.670.339288.7861.56
LDM8.460.34227,581.56387.25
HiFill64.070.43872.122.72
MI-GAN (ours)10.000.34515.695.98
", + "image_path": "163d3c0ee3197d8b1ad3c5c2a6130102949fd0170f01bf47454a43830cfaf7e1.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "table_body" + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 312, + 545, + 335 + ], + "lines": [ + { + "bbox": [ + 306, + 312, + 545, + 335 + ], + "spans": [ + { + "bbox": [ + 306, + 312, + 545, + 335 + ], + "type": "text", + "content": "Table 2. Quantitative comparison of our method with state-of-the-art approaches on 512 resolution images." + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 357, + 545, + 429 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 357, + 545, + 429 + ], + "spans": [ + { + "bbox": [ + 304, + 357, + 545, + 429 + ], + "type": "text", + "content": "while approaches like LaMa [53] and ZITS [15] produce blurry results on larger masks (see the 1st row of the figure as an example). Besides, as can be noticed from the qualitative comparison, on 256 resolution images our approach can perform better than the bigger and exceedingly computationally expensive model LDM [46]." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 430, + 545, + 490 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 430, + 545, + 490 + ], + "spans": [ + { + "bbox": [ + 304, + 430, + 545, + 490 + ], + "type": "text", + "content": "On higher resolution images (see Fig. 5) our model still produces semantically meaningful results. Besides, our results don't have a color inconsistency issue unlike LDM, LaMa and ZITS results (see the 1st row of the figure as an exemple)." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 491, + 545, + 538 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 491, + 545, + 538 + ], + "spans": [ + { + "bbox": [ + 304, + 491, + 545, + 538 + ], + "type": "text", + "content": "We also conduct a qualitative comparison on face images (see Fig. 7). On face images our model's results are on par with Co-Mod-GAN and SH-GAN, while being better than LaMa and MAT." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 540, + 545, + 563 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 540, + 545, + 563 + ], + "spans": [ + { + "bbox": [ + 304, + 540, + 545, + 563 + ], + "type": "text", + "content": "More qualitative results can be found in the supplementary material." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 306, + 574, + 380, + 586 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 574, + 380, + 586 + ], + "spans": [ + { + "bbox": [ + 306, + 574, + 380, + 586 + ], + "type": "text", + "content": "4.4. User Study" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "text", + "content": "In addition to comparing our MI-GAN model with SOTA inpainting methods, we conduct a user study against 5 built-in commercial mobile image inpainting apps. For this, we select a diverse set of 20 real world photos from OpenImages [30] dataset with varying resolutions and, using each method in comparison, carefully mask and remove predetermined objects from each photo. Then, we ask 3 people to anonymously rate each of 5 results from 1 to 5 for each photo and sum the given ratings for each method (see Fig. 6.a). As can be seen from the diagram, our approach has a" + } + ] + } + ], + "index": 24 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "7341" + } + ] + } + ], + "index": 25 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 70, + 289, + 189 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 289, + 189 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 289, + 189 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 289, + 189 + ], + "type": "table", + "html": "
Device Name256-resolution
MI-GAN speed (ms, mean/std)Co-Mod-GAN speed (ms, mean/std)
iPhone71030.25 / 13.374475.33 / 39.55
iPhoneX630.80 / 12.212746.00 / 28.84
iPad mini (5th gen)552.40 / 8.102686.17 / 41.41
iPhone14-pro-max296.00 / 1.351374.40 / 84.78
Galaxy Tab S7+686.17 / 12.36- / -
Samsung Galaxy S81476.40 / 5.98- / -
vivo Y122918.08 / 33.47- / -
", + "image_path": "198db144133bcb46bcc2d8664b45a50332b7e2f76e835e46b6169bd86a19afae.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 46, + 194, + 287, + 251 + ], + "lines": [ + { + "bbox": [ + 46, + 194, + 287, + 251 + ], + "spans": [ + { + "bbox": [ + 46, + 194, + 287, + 251 + ], + "type": "text", + "content": "Table 3. The actual speed of our 256 model vs Co-Mod-GAN 256 model deployed on various mobile devices. The actual speed is measured in milliseconds, the means and the stds of the speed are presented for each mobile device. Some numbers are missing, since Co-Mod-GAN was providing an out of memory error." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 273, + 288, + 321 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 273, + 288, + 321 + ], + "spans": [ + { + "bbox": [ + 46, + 273, + 288, + 321 + ], + "type": "text", + "content": "clear advantage over other methods. Fig. 6.b shows qualitative samples from user study, where our result has obvious advantage over commercial mobile apps. We include more results in the supplementary material." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 334, + 220, + 347 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 334, + 220, + 347 + ], + "spans": [ + { + "bbox": [ + 47, + 334, + 220, + 347 + ], + "type": "text", + "content": "4.5. Actual Speed on Mobile Devices" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 354, + 287, + 437 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 354, + 287, + 437 + ], + "spans": [ + { + "bbox": [ + 46, + 354, + 287, + 437 + ], + "type": "text", + "content": "Besides calculating FLOPS we also measure actual speed of our method on real mobile devices and compare MI-GAN with Co-Mod-GAN. As can be noticed from Table 3 on 256 resolution inputs our method is more than 4 times faster on average than Co-Mod-GAN, which allows MI-GAN to be used in real-world applications on mobile devices." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 440, + 288, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 440, + 288, + 536 + ], + "spans": [ + { + "bbox": [ + 46, + 440, + 288, + 536 + ], + "type": "text", + "content": "All models in Table 3 are using CPUs of mobile devices and are deployed by using the neural network framework ONNX [3]. Nothing special was conducted to optimize the speed or memory usage of MI-GAN on ONNX, so we believe MI-GAN can be further optimized in terms of speed or memory consumption (particularly running it on GPUs of mobile devices). The actual running times on 512 resolution images can be found in the supplementary material." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 549, + 141, + 562 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 549, + 141, + 562 + ], + "spans": [ + { + "bbox": [ + 47, + 549, + 141, + 562 + ], + "type": "text", + "content": "4.6. Ablation Study" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 570, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 288, + 715 + ], + "type": "text", + "content": "In this subsection we show the impact of our re-parametrization trick and knowledge distillation loss function for MI-GAN 256 resolution model. Both are designed to close the generative performance gap between MI-GAN and a larger inpainting network. Table 4 shows the quantitative effect of both. Fig. 8 shows that by adding re-parametrization trick we increase the semantic understanding of the model to generate more meaningful results. Further, the knowledge distillation adds more generative ability. Although both modifications has positive impact, one can notice that re-parametrization trick improves the method drastically (see also Fig. 8)." + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 314, + 70, + 537, + 129 + ], + "blocks": [ + { + "bbox": [ + 314, + 70, + 537, + 129 + ], + "lines": [ + { + "bbox": [ + 314, + 70, + 537, + 129 + ], + "spans": [ + { + "bbox": [ + 314, + 70, + 537, + 129 + ], + "type": "table", + "html": "
MethodFID ↓LPIPS ↓
Baseline14.940.407
Baseline + Re-Param12.220.400
MI-GAN: Baseline + Re-Param + KD11.830.39
", + "image_path": "53e89b24dcc61229749aa69e4bbea18339b89e682b2e9a0939fb52e2b9b87d36.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 305, + 133, + 547, + 167 + ], + "lines": [ + { + "bbox": [ + 305, + 133, + 547, + 167 + ], + "spans": [ + { + "bbox": [ + 305, + 133, + 547, + 167 + ], + "type": "text", + "content": "Table 4. The effect of model re-parametrization and knowledge distillation on MI-GAN 256 resolution model. As can be noticed both have positive impact in terms of both metrics FID and LPIPS." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 307, + 190, + 547, + 380 + ], + "blocks": [ + { + "bbox": [ + 307, + 190, + 547, + 380 + ], + "lines": [ + { + "bbox": [ + 307, + 190, + 547, + 380 + ], + "spans": [ + { + "bbox": [ + 307, + 190, + 547, + 380 + ], + "type": "image", + "image_path": "e34987006d4348a46ad2d4666217a9882257d3677d8ec9cc95a747e9368e7b83.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 384, + 545, + 407 + ], + "lines": [ + { + "bbox": [ + 305, + 384, + 545, + 407 + ], + "spans": [ + { + "bbox": [ + 305, + 384, + 545, + 407 + ], + "type": "text", + "content": "Figure 8. Visual results of ablation study on model reparametrization and knowledge distillation." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 439, + 486, + 453 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 439, + 486, + 453 + ], + "spans": [ + { + "bbox": [ + 306, + 439, + 486, + 453 + ], + "type": "text", + "content": "5. Limitations and Societal Impact" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 467, + 545, + 563 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 467, + 545, + 563 + ], + "spans": [ + { + "bbox": [ + 304, + 467, + 545, + 563 + ], + "type": "text", + "content": "Although our method has good generation abilities producing visually plausible results, similar to other state-of-the-art approaches it sometimes meets difficulties when reconstructing complex 3D structures. We hypothesize this can be later improved by guiding the network with more information about the 3D structure of the objects in images. For visual examples of MI-GAN's failure cases please see our supplementary material." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 570, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 546, + 714 + ], + "type": "text", + "content": "Our work aims to make the creative image editing easier and accessible for everyone with their mobile devices. Similar to other deep learning based image editing approaches our method may have both positive and negative societal impact depending on its application. As a positive impact MI-GAN can help the users to restore old photos or remove unpleasant objects from their photos making them more aesthetic. On the negative side it can be used to misrepresent the reality by removing important facts from the images. We strongly believe and hope that our work will give more positive value to creative editing users than its potential negative societal impact." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "7342" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 119, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 119, + 83 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 119, + 83 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 91, + 289, + 199 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 91, + 289, + 199 + ], + "spans": [ + { + "bbox": [ + 46, + 91, + 289, + 199 + ], + "type": "text", + "content": "In this paper we introduce MI-GAN, the first generative mobile image inpainting network. By using depthwise separable convolutions, model re-parametrization, and knowledge distillation, MI-GAN is able to produce high-quality results while having a low computational cost and a small number of parameters. Qualitative and quantitative comparisons show that MI-GAN is comparable or sometimes outperforms the current state-of-the-art approaches while being a way faster and smaller." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 210, + 107, + 222 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 210, + 107, + 222 + ], + "spans": [ + { + "bbox": [ + 48, + 210, + 107, + 222 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 229, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 53, + 229, + 287, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 229, + 287, + 274 + ], + "spans": [ + { + "bbox": [ + 53, + 229, + 287, + 274 + ], + "type": "text", + "content": "[1] Angeline Aguinaldo, Ping-Yeh Chiang, Alex Gain, Ameya Patil, Kolten Pearson, and Soheil Feizi. Compressing gans using knowledge distillation. arXiv preprint arXiv:1902.00159, 2019. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 274, + 287, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 274, + 287, + 308 + ], + "spans": [ + { + "bbox": [ + 53, + 274, + 287, + 308 + ], + "type": "text", + "content": "[2] Michael Ashikhmin. Synthesizing natural textures. In Proceedings of the 2001 symposium on Interactive 3D graphics, pages 217-226, 2001. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 309, + 287, + 341 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 309, + 287, + 341 + ], + "spans": [ + { + "bbox": [ + 53, + 309, + 287, + 341 + ], + "type": "text", + "content": "[3] Junjie Bai, Fang Lu, Ke Zhang, et al. Onnx: Open neural network exchange. https://github.com/onnx/onnx, 2019.8" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 342, + 287, + 387 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 342, + 287, + 387 + ], + "spans": [ + { + "bbox": [ + 53, + 342, + 287, + 387 + ], + "type": "text", + "content": "[4] Connelly Barnes, Eli Shechtman, Adam Finkelstein, and Dan B Goldman. Patchmatch: A randomized correspondence algorithm for structural image editing. ACM Trans. Graph., 28(3):24, 2009. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 388, + 287, + 432 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 388, + 287, + 432 + ], + "spans": [ + { + "bbox": [ + 53, + 388, + 287, + 432 + ], + "type": "text", + "content": "[5] Marcelo Bertalmio, Guillermo Sapiro, Vincent Caseles, and Coloma Ballester. Image inpainting. In Proceedings of the 27th annual conference on Computer graphics and interactive techniques, pages 417-424, 2000. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 433, + 287, + 476 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 433, + 287, + 476 + ], + "spans": [ + { + "bbox": [ + 53, + 433, + 287, + 476 + ], + "type": "text", + "content": "[6] Marcelo Bertalmio, Luminita Vese, Guillermo Sapiro, and Stanley Osher. Simultaneous structure and texture image inpainting. IEEE transactions on image processing, 12(8):882-889, 2003. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 478, + 287, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 478, + 287, + 510 + ], + "spans": [ + { + "bbox": [ + 53, + 478, + 287, + 510 + ], + "type": "text", + "content": "[7] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. arXiv preprint arXiv:1809.11096, 2018.3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 512, + 287, + 544 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 512, + 287, + 544 + ], + "spans": [ + { + "bbox": [ + 53, + 512, + 287, + 544 + ], + "type": "text", + "content": "[8] Tony F Chan and Jianhong Shen. Nontexture inpainting by curvature-driven diffusions. Journal of visual communication and image representation, 12(4):436-449, 2001. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 53, + 545, + 287, + 578 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 545, + 287, + 578 + ], + "spans": [ + { + "bbox": [ + 53, + 545, + 287, + 578 + ], + "type": "text", + "content": "[9] Ting-Yun Chang and Chi-Jen Lu. Tinygan: Distilling big-gan for conditional image generation. In Proceedings of the Asian Conference on Computer Vision, 2020. 2, 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 579, + 287, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 579, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 48, + 579, + 287, + 635 + ], + "type": "text", + "content": "[10] Hanting Chen, Yunhe Wang, Han Shu, Changyuan Wen, Chunjing Xu, Boxin Shi, Chao Xu, and Chang Xu. Distilling portable generative adversarial networks for image translation. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 3585-3592, 2020. 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 635, + 287, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 635, + 287, + 668 + ], + "spans": [ + { + "bbox": [ + 48, + 635, + 287, + 668 + ], + "type": "text", + "content": "[11] Shoufa Chen, Yunpeng Chen, Shuicheng Yan, and Jiashi Feng. Efficient differentiable neural architecture search with meta kernels. ArXiv, abs/1912.04749, 2019. 4" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "type": "text", + "content": "[12] Yunjey Choi, Youngjung Uh, Jaejun Yoo, and Jung-Woo Ha. Stargan v2: Diverse image synthesis for multiple domains. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 8188-8197, 2020. 3" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 32, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "text", + "content": "[13] Antonio Criminisi, Patrick Pérez, and Kentaro Toyama. Region filling and object removal by exemplar-based image inpainting. IEEE Transactions on image processing, 13(9):1200-1212, 2004. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 118, + 545, + 174 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 545, + 174 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 545, + 174 + ], + "type": "text", + "content": "[14] Xiaohan Ding, Tianxiang Hao, Jianchao Tan, Ji Liu, Jungong Han, Yuchen Guo, and Guiguang Ding. Resrep: Lossless cnn pruning via decoupling remembering and forgetting. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4510-4520, 2021. 5" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 175, + 545, + 230 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 175, + 545, + 230 + ], + "spans": [ + { + "bbox": [ + 307, + 175, + 545, + 230 + ], + "type": "text", + "content": "[15] Qiaole Dong, Chenjie Cao, and Yanwei Fu. Incremental transformer structure enhanced image inpainting with masking positional encoding. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11358-11368, 2022. 2, 5, 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 232, + 545, + 276 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 232, + 545, + 276 + ], + "spans": [ + { + "bbox": [ + 308, + 232, + 545, + 276 + ], + "type": "text", + "content": "[16] Alexei A Efros and William T Freeman. Image quilting for texture synthesis and transfer. In Proceedings of the 28th annual conference on Computer graphics and interactive techniques, pages 341-346, 2001. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 277, + 545, + 321 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 277, + 545, + 321 + ], + "spans": [ + { + "bbox": [ + 308, + 277, + 545, + 321 + ], + "type": "text", + "content": "[17] Alexei A Efros and Thomas K Leung. Texture synthesis by non-parametric sampling. In Proceedings of the seventh IEEE international conference on computer vision, volume 2, pages 1033-1038. IEEE, 1999. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 323, + 461, + 334 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 323, + 461, + 334 + ], + "spans": [ + { + "bbox": [ + 308, + 323, + 461, + 334 + ], + "type": "text", + "content": "[18] ADVA Soft GmbH. Touchretouch. 1" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 335, + 545, + 379 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 335, + 545, + 379 + ], + "spans": [ + { + "bbox": [ + 308, + 335, + 545, + 379 + ], + "type": "text", + "content": "[19] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. Communications of the ACM, 63(11):139–144, 2020. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 380, + 545, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 380, + 545, + 403 + ], + "spans": [ + { + "bbox": [ + 308, + 380, + 545, + 403 + ], + "type": "text", + "content": "[20] Paul Harrison. A non-hierarchical procedure for re-synthesis of complex textures. 2001. 2" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 404, + 545, + 459 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 404, + 545, + 459 + ], + "spans": [ + { + "bbox": [ + 308, + 404, + 545, + 459 + ], + "type": "text", + "content": "[21] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in neural information processing systems, 30, 2017. 5" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 461, + 545, + 495 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 461, + 545, + 495 + ], + "spans": [ + { + "bbox": [ + 308, + 461, + 545, + 495 + ], + "type": "text", + "content": "[22] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Advances in Neural Information Processing Systems, 33:6840-6851, 2020. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 496, + 545, + 551 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 496, + 545, + 551 + ], + "spans": [ + { + "bbox": [ + 308, + 496, + 545, + 551 + ], + "type": "text", + "content": "[23] Mu Hu, Junyi Feng, Jiashen Hua, Baisheng Lai, Jianqiang Huang, Xiaojin Gong, and Xian-Sheng Hua. Online convolutional re-parameterization. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 568-577, 2022. 5" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 552, + 494, + 564 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 552, + 494, + 564 + ], + "spans": [ + { + "bbox": [ + 308, + 552, + 494, + 564 + ], + "type": "text", + "content": "[24] Adobe Inc. Photoshop express photo editor. 1" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 565, + 484, + 576 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 565, + 484, + 576 + ], + "spans": [ + { + "bbox": [ + 308, + 565, + 484, + 576 + ], + "type": "text", + "content": "[25] Picsart Inc. Picsart photo editor & video. 1" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 578, + 545, + 610 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 578, + 545, + 610 + ], + "spans": [ + { + "bbox": [ + 308, + 578, + 545, + 610 + ], + "type": "text", + "content": "[26] Paras Kapoor and Tien D. Bui. Tinystargan v2: Distilling stargan v2 for efficient diverse image synthesis for multiple domains. In BMVC, 2021. 2, 3" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 308, + 613, + 545, + 666 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 613, + 545, + 666 + ], + "spans": [ + { + "bbox": [ + 308, + 613, + 545, + 666 + ], + "type": "text", + "content": "[27] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In 2019 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4396-4405, 2019. 1, 3, 4, 5" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 308, + 669, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 669, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 669, + 545, + 713 + ], + "type": "text", + "content": "[28] Rolf Kohler, Christian Schuler, Bernhard Schölkopf, and Stefan Harmeling. Mask-specific inpainting with deep neural networks. In German conference on pattern recognition, pages 523-534. Springer, 2014. 2" + } + ] + } + ], + "index": 31 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "7343" + } + ] + } + ], + "index": 33 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 712 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 149 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 149 + ], + "type": "text", + "content": "[29] Alexander Kolesnikov, Alexey Dosovitskiy, Dirk Weissenborn, Georg Heigold, Jakob Uszkoreit, Lucas Beyer, Matthias Minderer, Mostafa Dehghani, Neil Houlsby, Sylvain Gelly, Thomas Unterthiner, and Xiaohua Zhai. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations (ICLR), 2021. 4" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 151, + 288, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 151, + 288, + 217 + ], + "spans": [ + { + "bbox": [ + 48, + 151, + 288, + 217 + ], + "type": "text", + "content": "[30] Alina Kuznetsova, Hassan Rom, Neil Alldrin, Jasper Uijlings, Ivan Krasin, Jordi Pont-Tuset, Shahab Kamali, Stefan Popov, Matteo Malloci, Alexander Kolesnikov, Tom Duerig, and Vittorio Ferrari. The open images dataset v4: Unified image classification, object detection, and visual relationship detection at scale. IJCV, 2020. 7" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 218, + 287, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 218, + 287, + 262 + ], + "spans": [ + { + "bbox": [ + 48, + 218, + 287, + 262 + ], + "type": "text", + "content": "[31] Vivek Kwatra, Arno Schödl, Irfan Essa, Greg Turk, and Aaron Bobick. Graphcut textures: Image and video synthesis using graph cuts. Acm transactions on graphics (tog), 22(3):277-286, 2003. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 263, + 287, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 263, + 287, + 297 + ], + "spans": [ + { + "bbox": [ + 48, + 263, + 287, + 297 + ], + "type": "text", + "content": "[32] Anat Levin, Assaf Zomet, and Yair Weiss. Learning how to inpaint from global image statistics. In ICCV, volume 1, pages 305-312, 2003. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 297, + 287, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 297, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 48, + 297, + 287, + 342 + ], + "type": "text", + "content": "[33] Jingyuan Li, Ning Wang, Lefei Zhang, Bo Du, and Dacheng Tao. Recurrent feature reasoning for image inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7760-7768, 2020. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 342, + 287, + 396 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 342, + 287, + 396 + ], + "spans": [ + { + "bbox": [ + 48, + 342, + 287, + 396 + ], + "type": "text", + "content": "[34] Wenbo Li, Zhe Lin, Kun Zhou, Lu Qi, Yi Wang, and Jiaya Jia. Mat: Mask-aware transformer for large hole image inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10758-10768, 2022. 2, 5" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 398, + 287, + 443 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 398, + 287, + 443 + ], + "spans": [ + { + "bbox": [ + 48, + 398, + 287, + 443 + ], + "type": "text", + "content": "[35] Zeqi Li, Ruowei Jiang, and Parham Aarabi. Semantic relation preserving knowledge distillation for image-to-image translation. In European conference on computer vision, pages 648-663. Springer, 2020. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 444, + 287, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 444, + 287, + 498 + ], + "spans": [ + { + "bbox": [ + 48, + 444, + 287, + 498 + ], + "type": "text", + "content": "[36] Guilin Liu, Fitsum A Reda, Kevin J Shih, Ting-Chun Wang, Andrew Tao, and Bryan Catanzaro. Image inpainting for irregular holes using partial convolutions. In Proceedings of the European conference on computer vision (ECCV), pages 85-100, 2018. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 499, + 287, + 553 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 499, + 287, + 553 + ], + "spans": [ + { + "bbox": [ + 48, + 499, + 287, + 553 + ], + "type": "text", + "content": "[37] Yuchen Liu, Zhixin Shu, Yijun Li, Zhe Lin, Federico Peruzzi, and Sun-Yuan Kung. Content-aware gan compression. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12156-12166, 2021. 2, 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 555, + 287, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 555, + 287, + 600 + ], + "spans": [ + { + "bbox": [ + 48, + 555, + 287, + 600 + ], + "type": "text", + "content": "[38] Ziwei Liu, Ping Luo, Xiaogang Wang, and Xiaou Tang. Deep learning face attributes in the wild. In Proceedings of International Conference on Computer Vision (ICCV), December 2015. 2, 6" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 601, + 165, + 613 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 601, + 165, + 613 + ], + "spans": [ + { + "bbox": [ + 48, + 601, + 165, + 613 + ], + "type": "text", + "content": "[39] Google LLC. Snapseed. 1" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 613, + 287, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 613, + 287, + 668 + ], + "spans": [ + { + "bbox": [ + 48, + 613, + 287, + 668 + ], + "type": "text", + "content": "[40] Andreas Lugmayr, Martin Danelljan, Andres Romero, Fisher Yu, Radu Timofte, and Luc Van Gool. Repaint: Inpainting using denoising diffusion probabilistic models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11461-11471, 2022. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 669, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 669, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 669, + 287, + 712 + ], + "type": "text", + "content": "[41] Lars Mescheder, Andreas Geiger, and Sebastian Nowozin. Which training methods for gans do actually converge? In International conference on machine learning, pages 3481-3490. PMLR, 2018. 4" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 712 + ], + "type": "list", + "angle": 0, + "index": 27, + "blocks": [ + { + "bbox": [ + 307, + 73, + 546, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 546, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 546, + 106 + ], + "type": "text", + "content": "[42] Shant Navasardyan and Marianna Ohanyan. The family of onion convolutions for image inpainting. International Journal of Computer Vision, pages 1-30, 2022. 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 107, + 546, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 546, + 206 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 546, + 206 + ], + "type": "text", + "content": "[43] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, Luca Antiga, Alban Desmaison, Andreas Kopf, Edward Yang, Zachary DeVito, Martin Raison, Alykhan Tejani, Sasank Chilamkurthy, Benoit Steiner, Lu Fang, Junjie Bai, and Soumith Chintala. Pytorch: An imperative style, high-performance deep learning library. In Advances in Neural Information Processing Systems 32, pages 8024-8035. Curran Associates, Inc., 2019. 5" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 207, + 546, + 240 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 207, + 546, + 240 + ], + "spans": [ + { + "bbox": [ + 307, + 207, + 546, + 240 + ], + "type": "text", + "content": "[44] Jimmy S Ren, Li Xu, Qiong Yan, and Wenxiu Sun. Shepard convolutional neural networks. Advances in neural information processing systems, 28, 2015. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 241, + 546, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 241, + 546, + 285 + ], + "spans": [ + { + "bbox": [ + 307, + 241, + 546, + 285 + ], + "type": "text", + "content": "[45] Yuxi Ren, Jie Wu, Xuefeng Xiao, and Jianchao Yang. Online multi-granularity distillation for gan compression. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6793-6803, 2021. 2, 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 286, + 547, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 286, + 547, + 342 + ], + "spans": [ + { + "bbox": [ + 308, + 286, + 547, + 342 + ], + "type": "text", + "content": "[46] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684-10695, 2022. 2, 5, 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 342, + 546, + 398 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 342, + 546, + 398 + ], + "spans": [ + { + "bbox": [ + 308, + 342, + 546, + 398 + ], + "type": "text", + "content": "[47] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image computing and computer-assisted intervention, pages 234-241. Springer, 2015. 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 399, + 546, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 399, + 546, + 453 + ], + "spans": [ + { + "bbox": [ + 308, + 399, + 546, + 453 + ], + "type": "text", + "content": "[48] Chitwan Sahara, William Chan, Huiwen Chang, Chris Lee, Jonathan Ho, Tim Salimans, David Fleet, and Mohammad Norouzi. Palette: Image-to-image diffusion models. In ACM SIGGRAPH 2022 Conference Proceedings, pages 1-10, 2022. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 454, + 546, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 454, + 546, + 498 + ], + "spans": [ + { + "bbox": [ + 308, + 454, + 546, + 498 + ], + "type": "text", + "content": "[49] Tim Salimans and Durk P Kingma. Weight normalization: A simple reparameterization to accelerate training of deep neural networks. Advances in neural information processing systems, 29, 2016. 5" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 499, + 546, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 499, + 546, + 533 + ], + "spans": [ + { + "bbox": [ + 308, + 499, + 546, + 533 + ], + "type": "text", + "content": "[50] Jianhong Shen and Tony F Chan. Mathematical models for local nontexture inpaintings. SIAM Journal on Applied Mathematics, 62(3):1019-1043, 2002. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 533, + 546, + 556 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 533, + 546, + 556 + ], + "spans": [ + { + "bbox": [ + 308, + 533, + 546, + 556 + ], + "type": "text", + "content": "[51] L Sifre and S Mallat. Rigid-motion scattering for image classification [phd thesis]. Ecole Polytechnique, 2014. 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 557, + 546, + 590 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 557, + 546, + 590 + ], + "spans": [ + { + "bbox": [ + 308, + 557, + 546, + 590 + ], + "type": "text", + "content": "[52] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. arXiv preprint arXiv:2010.02502, 2020. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 591, + 546, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 591, + 546, + 668 + ], + "spans": [ + { + "bbox": [ + 308, + 591, + 546, + 668 + ], + "type": "text", + "content": "[53] Roman Suvorov, Elizaveta Logacheva, Anton Mashikhin, Anastasia Remizova, Armenii Ashukha, Aleksei Silvestrov, Naejin Kong, Harshith Goka, Kiwoong Park, and Victor Lempitsky. Resolution-robust large mask inpainting with fourier convolutions. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 2149–2159, 2022. 2, 5, 7" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 669, + 546, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 669, + 546, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 669, + 546, + 712 + ], + "type": "text", + "content": "[54] Yuri Viazovetskyi, Vladimir Ivashkin, and Evgeny Kashin. Stylegan2 distillation for feed-forward image manipulation. In European conference on computer vision, pages 170-186. Springer, 2020. 2, 4" + } + ] + } + ], + "index": 26 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "7344" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 707 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 117 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 117 + ], + "type": "text", + "content": "[55] Z. Wang, E.P. Simoncelli, and A.C. Bovik. Multiscale structural similarity for image quality assessment. In The Thirty-Seventh Asilomar Conference on Signals, Systems & Computers, 2003, volume 2, pages 1398-1402 Vol.2, 2003. 7" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 118, + 287, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 118, + 287, + 162 + ], + "spans": [ + { + "bbox": [ + 49, + 118, + 287, + 162 + ], + "type": "text", + "content": "[56] Li-Yi Wei and Marc Levoy. Fast texture synthesis using tree-structured vector quantization. In Proceedings of the 27th annual conference on Computer graphics and interactive techniques, pages 479–488, 2000. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 163, + 287, + 196 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 163, + 287, + 196 + ], + "spans": [ + { + "bbox": [ + 48, + 163, + 287, + 196 + ], + "type": "text", + "content": "[57] Junyuan Xie, Linli Xu, and Enhong Chen. Image denoising and inpainting with deep neural networks. Advances in neural information processing systems, 25, 2012. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 196, + 287, + 251 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 196, + 287, + 251 + ], + "spans": [ + { + "bbox": [ + 48, + 196, + 287, + 251 + ], + "type": "text", + "content": "[58] Xingqian Xu, Shant Navasardyan, Vahram Tadevosyan, Andranik Sargsyan, Yadong Mu, and Humphrey Shi. Image completion with heterogeneously filtered spectral hints. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, 2023. 2, 5" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 251, + 287, + 306 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 251, + 287, + 306 + ], + "spans": [ + { + "bbox": [ + 48, + 251, + 287, + 306 + ], + "type": "text", + "content": "[59] Zili Yi, Qiang Tang, Shekoofeh Azizi, Daesik Jang, and Zhan Xu. Contextual residual aggregation for ultra high-resolution image inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7508-7517, 2020. 2, 5" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 307, + 287, + 352 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 307, + 287, + 352 + ], + "spans": [ + { + "bbox": [ + 48, + 307, + 287, + 352 + ], + "type": "text", + "content": "[60] Jiahui Yu, Zhe Lin, Jamei Yang, Xiaohui Shen, Xin Lu, and Thomas S Huang. Free-form image inpainting with gated convolution. In Proceedings of the IEEE/CVF international conference on computer vision, pages 4471-4480, 2019. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 352, + 287, + 395 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 352, + 287, + 395 + ], + "spans": [ + { + "bbox": [ + 48, + 352, + 287, + 395 + ], + "type": "text", + "content": "[61] Linfeng Zhang, Xin Chen, Runpei Dong, and Kaisheng Ma. Region-aware knowledge distillation for efficient image-to-image translation. arXiv preprint arXiv:2205.12451, 2022. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 396, + 287, + 452 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 396, + 287, + 452 + ], + "spans": [ + { + "bbox": [ + 48, + 396, + 287, + 452 + ], + "type": "text", + "content": "[62] Linfeng Zhang, Xin Chen, Xiaobing Tu, Pengfei Wan, Ning Xu, and Kaisheng Ma. Wavelet knowledge distillation: Towards efficient image-to-image translation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12464-12474, 2022. 2, 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 452, + 287, + 485 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 452, + 287, + 485 + ], + "spans": [ + { + "bbox": [ + 48, + 452, + 287, + 485 + ], + "type": "text", + "content": "[63] Mingyang Zhang, Xinyi Yu, Jingtao Rong, Linlin Ou, and Feng Gao. Repnas: Searching for efficient re-parameterizing blocks. arXiv preprint arXiv:2109.03508, 2021. 4" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 486, + 287, + 540 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 486, + 287, + 540 + ], + "spans": [ + { + "bbox": [ + 48, + 486, + 287, + 540 + ], + "type": "text", + "content": "[64] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 586-595, 2018. 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 541, + 287, + 596 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 541, + 287, + 596 + ], + "spans": [ + { + "bbox": [ + 48, + 541, + 287, + 596 + ], + "type": "text", + "content": "[65] Shengyu Zhao, Jonathan Cui, Yilun Sheng, Yue Dong, Xiao Liang, Eric I Chang, and Yan Xu. Large scale image completion via co-modulated generative adversarial networks. In International Conference on Learning Representations (ICLR), 2021. 2, 3, 4, 5, 7" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 597, + 287, + 652 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 597, + 287, + 652 + ], + "spans": [ + { + "bbox": [ + 48, + 597, + 287, + 652 + ], + "type": "text", + "content": "[66] Haitian Zheng, Zhe Lin, Jingwan Lu, Scott Cohen, Eli Shechtman, Connelly Barnes, Jianming Zhang, Ning Xu, Sohrab Amirghodsi, and Jiebo Luo. Cm-gan: Image inpainting with cascaded modulation gan and object-aware training. arXiv preprint arXiv:2203.11947, 2022. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 653, + 287, + 707 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 653, + 287, + 707 + ], + "spans": [ + { + "bbox": [ + 48, + 653, + 287, + 707 + ], + "type": "text", + "content": "[67] Bolei Zhou, Agata Lapedriza, Aditya Khosla, Aude Oliva, and Antonio Torralba. Places: A 10 million image database for scene recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 40(6):1452-1464, 2018. 1, 5" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "7345" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/323ff8ab-5b3c-4603-a4d5-667546c604d5_content_list.json b/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/323ff8ab-5b3c-4603-a4d5-667546c604d5_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..9d59aaa442d1b62c90851ac846f762b88f479386 --- /dev/null +++ b/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/323ff8ab-5b3c-4603-a4d5-667546c604d5_content_list.json @@ -0,0 +1,1794 @@ +[ + { + "type": "text", + "text": "MIMO-NeRF: Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields", + "text_level": 1, + "bbox": [ + 210, + 130, + 759, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Takuhiro Kaneko \nNTT Communication Science Laboratories, NTT Corporation", + "bbox": [ + 238, + 203, + 730, + 239 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 273, + 313, + 289 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Neural radiance fields (NeRFs) have shown impressive results for novel view synthesis. However, they depend on the repetitive use of a single-input single-output multilayer perceptron (SISO MLP) that maps 3D coordinates and view direction to the color and volume density in a sample-wise manner, which slows the rendering. We propose a multi-input multi-output NeRF (MIMO-NeRF) that reduces the number of MLPs running by replacing the SISO MLP with a MIMO MLP and conducting mappings in a group-wise manner. One notable challenge with this approach is that the color and volume density of each point can differ according to a choice of input coordinates in a group, which can lead to some notable ambiguity. We also propose a self-supervised learning method that regularizes the MIMO MLP with multiple fast reformulated MLPs to alleviate this ambiguity without using pretrained models. The results of a comprehensive experimental evaluation including comparative and ablation studies are presented to show that MIMO-NeRF obtains a good trade-off between speed and quality with a reasonable training time. We then demonstrate that MIMO-NeRF is compatible with and complementary to previous advancements in NeRFs by applying it to two representative fast NeRFs, i.e., a NeRF with a sampling network (DONeRF) and a NeRF with alternative representations (TensoRF).", + "bbox": [ + 76, + 306, + 473, + 684 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 714, + 209, + 729 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Images are two-dimensional (2D) projections of three-dimensional (3D) scenes. Solving the inverse problem, that is, learning 3D representations from 2D images and synthesizing novel views, is a fundamental concern in computer vision and graphics and has been extensively studied for various applications such as photo editing, content creation, virtual reality, and environmental understanding.", + "bbox": [ + 76, + 739, + 468, + 847 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "With the advent of implicit neural representations", + "bbox": [ + 96, + 847, + 468, + 863 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/da7cd6167e4c90517e2d9806f52c9dd8930bae0734d742314d72b4bb0c0f1f1b.jpg", + "image_caption": [ + "(a) NeRF" + ], + "image_footnote": [], + "bbox": [ + 501, + 271, + 696, + 385 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/0172601d03809291881bba5f36c935b4b3388c06f4ac60bfa296da32699e1cac.jpg", + "image_caption": [ + "(b) MIMO-NeRF (proposed)", + "Figure 1. Comparison between NeRF and MIMO-NeRF (proposed). (a) A typical NeRF uses a SISO MLP that maps 3D coordinates and view direction to the color and volume density in a sample-wise manner. (b) In contrast, the proposed MIMO-NeRF uses a MIMO MLP that performs mappings in a group-wise manner. This change reduces the number of MLPs running and improves the rendering speed, but also requires addressing ambiguity in the color and volume density caused by the fact that these values are determined in a non-unique manner by a set of input coordinates that vary by viewpoint, grouping, and sampling. The main technical contribution of the present work is that of providing methods to mitigate this challenge. We demonstrate the impact of the proposed technique in Figure 2." + ], + "image_footnote": [], + "bbox": [ + 696, + 271, + 890, + 385 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "(e.g., [56, 44, 39, 28, 69, 71, 55]), substantial advancements have been made towards addressing this problem. Neural radiance fields (NeRFs) [39] have been noted as a successful approach. A NeRF represents a scene using a continuous function that maps 3D coordinates and view direction to the color and volume density and renders a pixel by integrating the outputs on a ray using volume rendering [34]. This formulation enables NeRF to learn to synthesize geometrically consistent and high-fidelity novel views with only 2D supervision.", + "bbox": [ + 496, + 626, + 893, + 777 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Despite this advantage, a typical NeRF suffers from slow rendering because it uses a single-input single-output (SISO) MLP that calculates the RGB color and volume density in a sample-wise manner (Figure 1(a)). Although this architecture ensures the independent representation of each point, which is useful, for example, for learning view-independent volume density, its computational cost increases in proportion to the number of samples for each", + "bbox": [ + 496, + 779, + 893, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "1The project page is available at https://www.Kecl.ntt.co.jp/people/kaneko.takuhiro/projects/mimo-nerf/.", + "bbox": [ + 76, + 875, + 467, + 902 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "3273", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "ray (e.g., on the order of hundreds). Several methods developed to address this issue can be roughly categorized into two approaches, including (1) sample reduction and (2) alternative representations.", + "bbox": [ + 75, + 90, + 468, + 151 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "A typical sample reduction strategy reduces the number of samples on a ray using a sampling network based on the depth [41] or density of a pretrained NeRF [47] or using a sampling network with an adaptive optimization mechanism [29, 14, 27]. These methods successfully accelerate the rendering process while retaining the quality of an image adequately. However, most of these techniques still use a SISO MLP to predict the colors and volume densities of selected samples; therefore, they still need to run MLPs many times in proportion to the number of selected samples. This issue can be alleviated by reducing the number of selected samples, although this deteriorates the quality of the synthesized images accordingly.", + "bbox": [ + 75, + 152, + 470, + 348 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "As alternative representations, various sophisticated and faster representations such as 3D voxel grids [17, 22, 30, 66, 60], sparse voxel-based octrees [70, 15], multiplane images [65], tri-planes [7], vector-matrix decomposition [9], hashes [40], NeRF-specific structures [24], and space-wise MLPs [50, 51] have been devised. These representations contribute to achieving fast rendering while retaining image quality moderately well. However, after powerful features are extracted using alternative representations, SISO MLPs are still commonly used for the final prediction of color or volume density owing to their memory-efficient and continuous nature. Hence, part of the calculation cost still increases depending on the number of samples.", + "bbox": [ + 75, + 348, + 470, + 545 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Consequently, owing to its compact, continuous (i.e., resolution-free), and independent (e.g., view-independent) nature, a SISO MLP is commonly used in various NeRFs. However, as mentioned above, the calculation cost increases with the number of samples. This is not preferable when considering the improvement in rendering speed. Possible simple solutions include, for example, a reduction of the number of samples or a reduction of the size of a model with a corresponding sacrifice of image quality. However, these solutions are not necessarily the best for handling the tradeoff between quality and speed. Alternatively, we propose a multi-input multi-output NeRF (MIMO-NeRF), which is a novel variant of NeRF that represents a scene using a MIMO MLP that conducts mappings in a group-wise manner (Figure 1(b)). This modification enables a reduction in the number of MLPs running according to the number of grouped samples and consequently improves rendering speed.", + "bbox": [ + 75, + 545, + 468, + 801 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "However, in this approach, the uniqueness of the color and volume density of each point is not ensured because they are determined not only by the coordinates of the corresponding point but also by the coordinates of the other points in a group, which vary by viewpoint, grouping, and", + "bbox": [ + 75, + 801, + 470, + 878 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/f456a4e5b7fbb311e92d30b9fe46fcd072e7686ff936ab9c219de744be5a1438.jpg", + "image_caption": [ + "Figure 2. Challenge of training MIMO-NeRF and the impact of the proposed self-supervised learning. (a) MIMO-NeRF-naive suffers from ambiguity in the color and volume density of each point and deteriorates image quality. (b) We propose self-supervised learning to address this problem without relying on a pretrained model. This technique improves image quality." + ], + "image_footnote": [], + "bbox": [ + 506, + 88, + 888, + 220 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "sampling. This leads to some ambiguity and causes fluctuation artifacts as shown in Figure 2(a). In particular, this ambiguity can be problematic when learning a 3D representation using only 2D supervision because obtaining direct supervision that can resolve the ambiguity is difficult. One possible solution is to train a standard (i.e., SISO) NeRF first and then distill the model onto the corresponding MIMO-NeRF. However, this increases training time because both student and teacher NeRFs must be trained. Alternatively, we have also developed a novel self-supervised learning approach in which we reformulate a MIMO MLP in several ways (in particular, we use group shift (Figure 3) and variation reduction (Figure 4)) and impose a consistent regularization so that the reformulated MIMO MLPs produce the same outputs. Because each reformulated MIMO MLP can render a pixel faster than the original SISO MLP, we can prevent a large sacrifice of training time even when using multiple reformulated MIMO MLPs by adequately adjusting the reformulation configuration. Figure 2(b) shows an example of the effects of this learning scheme.", + "bbox": [ + 496, + 342, + 892, + 657 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We investigated the benchmark performance of MIMO-NeRF by comparing it with possible alternatives (including the distillation of a pretrained NeRF, sample reduction, and reduction of the model size). We also performed ablation studies to examine the validity of each component of the proposed self-supervised learning method. We apply MiMO-NeRF to two representative fast NeRFs, including a NeRF with a sampling network (DONeRF [41]) and a model with alternative representations (TensoRF [9]) to demonstrate that it is compatible with and complementary to previous advancements in NeRFs.", + "bbox": [ + 496, + 660, + 890, + 825 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The main contributions of this study are summarized as follows.", + "bbox": [ + 500, + 827, + 890, + 856 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "- To speed up the rendering of NeRF, we propose MIMO-NeRF, which represents a scene using a MIMO", + "bbox": [ + 517, + 869, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_footnote", + "text": "2We discuss this trade-off in detail in Section 5.2.", + "bbox": [ + 94, + 886, + 357, + 898 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "3274", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "MLP that maps the coordinates on a ray to the colors and volume densities in a group-wise manner.", + "bbox": [ + 107, + 90, + 467, + 119 + ], + "page_idx": 2 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We introduce novel self-supervised learning to mitigate the ambiguity in the color and volume density of each point and enable MIMO-NeRF to be trained without relying on pretrained models.", + "- We examined the effectiveness of MIMO-NeRF through a comprehensive experimental evaluation, and the results demonstrate the versatility of MIMO-NeRF in applications to two representative fast NeRFs. We also provide more detailed analyses and extended results in the Supplementary Material." + ], + "bbox": [ + 96, + 125, + 467, + 279 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2. Related work", + "text_level": 1, + "bbox": [ + 76, + 292, + 212, + 308 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Implicit neural representations. Implicit neural representations have attracted attention in 3D shape [45, 35, 11, 36, 52, 18, 3, 20] and 3D scene [25, 46, 6, 12, 54] reconstructions owing to their memory-efficient, continuous (i.e., resolution-free), and 3D-aware characteristics. Although research began with explicit 3D supervision, learning implicit 3D only from 2D supervision (i.e., inverse graphics) has also been achieved by incorporating differentiable rendering [56, 31, 44, 32, 39, 28, 69, 71, 55]. In this study, we focus on NeRFs as a representative example of the latter owing to their remarkable success in synthesizing geometrically consistent and high-quality novel view. However, applying our ideas to other implicit neural representations, such as those mentioned above, remains as an interesting direction for future research.", + "bbox": [ + 76, + 318, + 467, + 544 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Advancements in NeRFs. Various extensions have been proposed since the emergence of NeRF. For example, representative research topics include (1) improving image quality and enhancing applicable scenes (e.g., [72, 33, 49, 16, 67, 4, 5, 37, 62, 10]), (2) incorporation into other models, e.g., deep generative models, such as generative adversarial networks (GANs) [19] and diffusion probabilistic models [58, 23] (e.g., [53, 8, 43, 42, 21, 7, 13, 68, 26, 57, 48]), and (3) accelerating NeRFs for fast inference or fast training (e.g., [41, 47, 29, 14, 27, 17, 22, 30, 66, 60, 70, 15, 65, 7, 9, 40, 24, 50, 51]). The present work falls into the third category. However, our proposed approach is complementary to previous studies, including most of the abovementioned works in all categories, because SISO MLPs have commonly been used as a partial or main network in previous studies and improving their rendering speed by replacing SISO MLPs with the proposed MIMO MLP is feasible. The results of the experimental evaluation validated this potential (Sections 5.4 and 5.5).", + "bbox": [ + 76, + 549, + 467, + 835 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Acceleration of NeRFs. As discussed in Section 1, a typical NeRF is well known for its slow rendering because it use a SISO MLP. Several approaches have been developed to address this issue. These can be roughly categorized", + "bbox": [ + 76, + 839, + 467, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "into two approaches, including (1) sample reduction and (2) alternative representations. (1) As described in Section 1, methods that reduce the number of samples using a sampling network can improve rendering speed by replacing a SISO MLP with the proposed MIMO MLP. We validated this statement during an experiment (Section 5.4) by applying our ideas to a representative NeRF in this category (DONeRF [41]). Another common approach in the first category is to render pixels using a light-field network [55, 2, 59, 63] instead of volume rendering [34]. This approach has been shown to achieve fast rendering by running only a single MLP for a given ray. However, owing to the lack of explicit geometry-aware representations driven by the use of volume densities, these methods suffer from limitations that are not faced by a standard NeRF in terms of restrictions on applicable scenes (e.g., toy datasets [55] and forward-facing datasets [2]), a requirement for high-capacity models (e.g., a deeper MLP [63] and a transformer [59]), and the need for extra modules (e.g., metalearned priors [55], pretrained NeRFs [2, 63], or additional encoders [59]). (2) As explained in Section 1, alternative representations have the potential to accelerate the rendering speed by replacing the SISO MLP with the proposed MIMO MLP. We present an empirical investigation of this potential in Section 5.5 by incorporating MIMO-NeRF into TensoRF [9], a representative model in this category.", + "bbox": [ + 496, + 90, + 890, + 484 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Learning of fast NeRFs. Knowledge distillation (or baking) methods are commonly used to train fast NeRFs. In these methods, a standard NeRF is first trained and then baked to faster representations [17, 22, 24, 50, 51]. However, this approach is disadvantageous in terms of training time because two separate models must be trained, i.e., teacher and student NeRFs. As an alternative, we consider a self-supervised learning approach in which we can train a model without a large increase in training time. We examine the performance differences between the proposed self-supervised learning scheme and a knowledge distillation scheme in Section 5.1.", + "bbox": [ + 496, + 486, + 890, + 667 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Preliminaries: NeRF", + "text_level": 1, + "bbox": [ + 500, + 678, + 697, + 694 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We begin by explaining NeRFs as the basis for our model. As shown in Figure 1(a), a NeRF represents a point in a 3D space using a continuous SISO function $f_{\\mathrm{SISO}}$ that maps the 3D position $\\mathbf{x} \\in \\mathbb{R}^3$ and view direction $\\mathbf{d} \\in \\mathbb{S}^2$ to the RGB color $\\mathbf{c}(\\mathbf{x}, \\mathbf{d}) \\in \\mathbb{R}^3$ and volume density $\\sigma(\\mathbf{x}) \\in \\mathbb{R}^+$ in a sample-wise manner.", + "bbox": [ + 496, + 704, + 890, + 795 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nf _ {\\mathrm {S I S O}}: \\mathbb {R} ^ {3} \\times \\mathbb {S} ^ {2} \\rightarrow \\mathbb {R} ^ {3} \\times \\mathbb {R} ^ {+}, (\\mathbf {x}, \\mathbf {d}) \\mapsto (\\mathbf {c}, \\sigma). \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 526, + 800, + 890, + 818 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Specifically, positional encoding [39, 61] is applied to $\\mathbf{x}$ and $\\mathbf{d}$ to represent the high-frequency details of an image. Subsequently, an MLP is applied to the encoded inputs to obtain $\\mathbf{c}$ and $\\sigma$ . For simplicity, we represent these series of processes in a unified manner as $f_{\\mathrm{SISO}}$ .", + "bbox": [ + 496, + 824, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "3275", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "A NeRF is based on ray tracing, in which a camera ray is defined as $\\mathbf{r}(t) = \\mathbf{o} + t\\mathbf{d}$ , where $\\mathbf{o}$ and $\\mathbf{d}$ respectively denote the origin and direction of the camera and $t$ denotes a distance from the origin. A NeRF calculates the color of each pixel $\\hat{\\mathbf{C}}(\\mathbf{r})$ by integrating the colors and volume densities on a ray $\\mathbf{r}(t)$ within $t \\in [t_n, t_f]$ using volume rendering [34]. In implementation, the calculation of the integral is intractable; therefore, a ray is discretized into $N$ points; alternatively, the following discretized formulation can be used.", + "bbox": [ + 75, + 90, + 472, + 241 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {\\mathbf {C}} (\\mathbf {r}) = \\sum_ {i = 1} ^ {N} T _ {i} \\alpha_ {i} \\mathbf {c} _ {i}, \\text {w h e r e} T _ {i} = \\prod_ {j = 1} ^ {i - 1} (1 - \\alpha_ {j}), \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 119, + 250, + 468, + 292 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where the subscript $i$ indicates that the variable corresponds to the $i$ -th point on a ray, $\\alpha_{i} = 1 - \\exp (-\\sigma_{i}\\delta_{i})$ is an alpha value, and $\\delta_{i} = t_{i + 1} - t_{i}$ is the distance between the $i$ -th and $(i + 1)$ -th points. $f_{\\mathrm{SISO}}$ is optimized by minimizing the following pixel-wise loss.", + "bbox": [ + 75, + 303, + 468, + 378 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {p i x e l}} = \\| \\hat {\\mathbf {C}} (\\mathbf {r}) - \\mathbf {C} (\\mathbf {r}) \\| _ {2} ^ {2}, \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 183, + 388, + 468, + 407 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbf{C}(\\mathbf{r})$ is the ground-truth color for a ray $\\mathbf{r}$ . In practice, this loss is calculated for $\\mathbf{r} \\in \\mathcal{R}$ , where $\\mathcal{R}$ denotes a set of rays in each batch.", + "bbox": [ + 75, + 417, + 468, + 462 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In practice, a NeRF uses coarse and fine networks. In the coarse network, a ray is discretized into $N_{c}$ points using stratified sampling, whereas in the fine network, a ray is discretized into $N_{c} + N_{f}$ points using hierarchical sampling in which $N_{f}$ additional points are sampled according to the output of the coarse network. The two networks are optimized by minimizing $\\mathcal{L}_{\\mathrm{pixel}}$ for $\\hat{\\mathbf{C}}(\\mathbf{r})$ predicted by each network. Hereafter, we omit a variable in parentheses (e.g., $(\\mathbf{r})$ ) for simplicity.", + "bbox": [ + 75, + 463, + 468, + 599 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. MIMO-NeRF", + "text_level": 1, + "bbox": [ + 76, + 612, + 217, + 628 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. MIMO formulation", + "text_level": 1, + "bbox": [ + 76, + 637, + 264, + 652 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "There are several ways to group the input samples when constructing a MIMO MLP. For example, we can construct a general MLP that can accept any combination of samples in a 3D space, or we can construct a specific MLP that only accepts a group of nearby samples. In preliminary experiments (Appendix A.1), we found that the latter significantly outperformed the former because general models are more difficult to train than more specific models. Therefore, we adopted the latter in this study. In particular, we group neighboring samples on a ray as shown in Figure 1(b).3", + "bbox": [ + 75, + 660, + 468, + 811 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "More formally, given $N$ samples on a ray, we group $N_{p}$ samples from the sample nearest to the camera and create", + "bbox": [ + 75, + 811, + 468, + 842 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "$N / N_{p}$ groups. Subsequently, we apply a MIMO function $f_{\\mathrm{MIMO}}$ to each group as follows.", + "bbox": [ + 500, + 90, + 890, + 121 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} f _ {\\mathrm {M I M O}}: (\\mathbb {R} ^ {3}) ^ {N _ {p}} \\times \\mathbb {S} ^ {2} \\rightarrow (\\mathbb {R} ^ {3} \\times \\mathbb {R} ^ {+}) ^ {N _ {p}}, \\\\ \\left(\\mathbf {x} _ {i}, \\dots , \\mathbf {x} _ {j}, \\mathbf {d}\\right) \\mapsto \\left(\\mathbf {c} _ {i}, \\dots , \\mathbf {c} _ {j}, \\sigma_ {i}, \\dots , \\sigma_ {j}\\right), \\tag {4} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 521, + 127, + 890, + 164 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $i \\in \\{1, 1 + N_p, \\dots, 1 + N - N_p\\}$ and $j = i + N_p - 1$ . Assuming that the grouped samples are lined on a ray, we use a single direction $\\mathbf{d}$ in the input of $f_{\\mathrm{MIMO}}$ . In this formulation, the number of MLPs running to render a pixel (#Run) is equal to the number of groups and is calculated as #Run = $N / N_p$ . Therefore, we can reduce the calculation cost, particularly that of #Run, by increasing $N_p$ .", + "bbox": [ + 498, + 170, + 890, + 276 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In inference, the only necessary modification to a NeRF is the simple replacement of $f_{\\mathrm{SISO}}$ with $f_{\\mathrm{MIMO}}$ and the same volume rendering (Equation 2) and sampling scheme (i.e., stratified and hierarchical sampling) can be used. With this modification strategy, MIMO-NeRF exhibits high compatibility and complementarity with previous NeRFs.", + "bbox": [ + 496, + 277, + 890, + 366 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "During training, $\\mathcal{L}_{\\mathrm{pixel}}$ (Equation 3) can be used for $\\hat{\\mathbf{C}}$ obtained using $f_{\\mathrm{MIMO}}$ . However, this loss does not necessarily suffice to address the ambiguity in the color and volume density of each point because this ambiguity occurs in a 3D space and the loss cannot regularize the 3D representations explicitly. Hence, we introduce self-supervised learning as discussed in subsequent sections.", + "bbox": [ + 496, + 366, + 890, + 473 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.2. MIMO reformulation", + "text_level": 1, + "bbox": [ + 500, + 479, + 702, + 494 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "One possible solution to this ambiguity is to train a standard (i.e., SISO) NeRF first and then distill the model onto a corresponding MIMO-NeRF. However, this solution involves an increase in training time because it requires training not only a MIMO-NeRF but also a SISO NeRF. Consequently, this solution cannot entirely take advantage of the fast rendering of MIMO-NeRF in training.", + "bbox": [ + 496, + 503, + 890, + 609 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Alternatively, we reformulate a MIMO MLP in multiple ways and impose a consistent regularization to produce the same RGB colors and alpha values. Because each reformulated MIMO MLP can render a pixel faster than the original SISO MLP, we can prevent a large increase in training time even when using multiple reformulated MIMO MLPs by adequately adjusting the reformulation configuration. When implementing this idea, the question arises as to how best to reformulate a MIMO MLP. To this end, we developed two methods, including (1) group shift and (2) variation reduction.", + "bbox": [ + 496, + 609, + 890, + 773 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Group shift. We consider restricting this ambiguity by assessing each point in multiple ways using different groups and imposing consistency on the assessed results. More formally, we implement this by shifting groups and rewriting Equation 4 as follows.", + "bbox": [ + 496, + 777, + 890, + 853 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} f _ {\\mathrm {M I M O}} ^ {\\mathrm {s h i f t}}: (\\mathbb {R} ^ {3}) ^ {N _ {p}} \\times \\mathbb {S} ^ {2} \\to (\\mathbb {R} ^ {3} \\times \\mathbb {R} ^ {+}) ^ {N _ {p}}, \\\\ \\left(\\mathbf {x} _ {i ^ {\\prime}}, \\dots , \\mathbf {x} _ {j ^ {\\prime}}, \\mathbf {d}\\right) \\mapsto \\left(\\mathbf {c} _ {i ^ {\\prime}}, \\dots , \\mathbf {c} _ {j ^ {\\prime}}, \\sigma_ {i ^ {\\prime}}, \\dots , \\sigma_ {j ^ {\\prime}}\\right), \\tag {5} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 513, + 859, + 890, + 897 + ], + "page_idx": 3 + }, + { + "type": "page_footnote", + "text": "3One possible alternative is to group near samples on different rays. However, in NeRFs, searching near points across different rays is not trivial because points are sampled unevenly via hierarchical sampling. Therefore, we simply group neighboring samples on the same ray in this study.", + "bbox": [ + 75, + 849, + 468, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "3276", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/379aed44382020f4991b234dce1376b248d3a1ead134d95e989fb0597105b79b.jpg", + "image_caption": [ + "Figure 3. Example of the group shift when $N_{p} = 4$ and $s = 2$ . We shift each group by $s$ toward the camera after padding $s$ samples before the front sample. This procedure enables assessing each sample in multiple ways using different groups." + ], + "image_footnote": [], + "bbox": [ + 76, + 88, + 472, + 181 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $i' \\in \\{k, k + N_p, \\ldots, k + N\\}$ and $j' = i' + N_p - 1$ . Here, $k$ is the head index of the first group, which is shifted by $s \\in \\{1, \\ldots, N_p - 1\\}$ toward the camera. Hence, $k \\in \\{2 - N_p, \\ldots, 0\\}$ . In practice, it is randomly sampled during training. More strictly, we add padding before this process to represent a sample with an index exceeding the original index, i.e., $i' < 1$ or $j' > N$ . For clarity, we present an example in which $N_p = 4$ and $s = 2$ in Figure 3.", + "bbox": [ + 76, + 273, + 468, + 397 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Variation reduction. In the original MIMO formulation, the abovementioned ambiguity is caused by $N_{p}$ different input samples. To mitigate this, we consider reducing the variation in the input by replacing Equation 4 with the following.", + "bbox": [ + 75, + 398, + 470, + 474 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nf _ {\\mathrm {M I M O}} ^ {\\text {r e d u c e}}: (\\mathbb {R} ^ {3}) ^ {N _ {p}} \\times \\mathbb {S} ^ {2} \\to (\\mathbb {R} ^ {3} \\times \\mathbb {R} ^ {+}) ^ {N _ {p}},\n$$\n", + "text_format": "latex", + "bbox": [ + 91, + 484, + 357, + 503 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\left(\\left[ \\mathbf {x} _ {i ^ {\\prime \\prime}} \\right] ^ {R}, \\ldots , \\left[ \\mathbf {x} _ {j ^ {\\prime \\prime}} \\right] ^ {R}, \\mathbf {d}\\right) \\mapsto \\left(\\mathbf {c} _ {i _ {1} ^ {\\prime \\prime}}, \\ldots , \\mathbf {c} _ {i _ {R} ^ {\\prime \\prime}}, \\ldots , \\mathbf {c} _ {j _ {1} ^ {\\prime \\prime}}, \\ldots , \\mathbf {c} _ {j _ {R} ^ {\\prime \\prime}}, \\right. \\\\ \\sigma_ {i _ {1} ^ {\\prime \\prime}}, \\dots , \\sigma_ {i _ {R} ^ {\\prime \\prime}}, \\dots , \\sigma_ {j _ {1} ^ {\\prime \\prime}}, \\dots , \\sigma_ {j _ {R} ^ {\\prime \\prime}}), \\tag {6} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 80, + 506, + 472, + 561 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $[\\cdot ]^R$ denotes the operation of repeating the given variable $R$ times, $i''\\in \\{1,1 + \\frac{N_p}{R},\\ldots ,1 + N - \\frac{N_p}{R}\\}$ , and $j^{\\prime \\prime} = i^{\\prime \\prime} + \\frac{N_p}{R} -1$ . After applying $f_{\\mathrm{MIMO}}^{\\mathrm{reduce}}$ , we average $(\\mathbf{c}_{k_1^{\\prime \\prime}},\\dots,\\mathbf{c}_{k_R^{\\prime \\prime}})$ and $(\\sigma_{k_1^{\\prime \\prime}},\\dots,\\sigma_{k_R^{\\prime \\prime}})$ to obtain $\\mathbf{c}_{k^{\\prime \\prime}}$ and $\\sigma_{k^{\\prime \\prime}}$ , where $k^{\\prime \\prime}\\in \\{i^{\\prime \\prime},\\dots,j^{\\prime \\prime}\\}$ . In this formulation, the mentioned ambiguity is reduced by decreasing input variation from $N_{p}$ to $\\frac{N_p}{R}$ . Conversely, the number of MLPs running increases by factor of $R$ , i.e., $\\# \\operatorname {Run} = N / N_p\\times R$ ; therefore, we need to select $R$ carefully in practice to avoid a large increase in training time. For clarity, we present an example case in which $N_{p} = 4$ and $R = 2$ in Figure 4.", + "bbox": [ + 75, + 574, + 468, + 748 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.3. MIMO objective", + "text_level": 1, + "bbox": [ + 76, + 756, + 240, + 772 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Through the above processes, we obtain $M$ reformulated MIMO MLPs in which we use different $s$ for each MIMO MLP and set $R$ such that the total number of # Run is not larger than that of the original SISO MLP. Hereafter, we use the superscript $m \\in \\{1, \\dots, M\\}$ to denote the variable corresponding to the $m$ -th reformulated MIMO MLP, e.g., $\\hat{\\mathbf{C}}^m$ and $R^m$ . We train these MLPs using two loss functions, including pixel-wise and 3D consistency losses.", + "bbox": [ + 75, + 779, + 470, + 902 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/c887b051e676ac30bc781ef5cfb2f4ef8250c929a58630e1cd808f8722c54e7c.jpg", + "image_caption": [ + "Figure 4. Example of variation reduction when $N_{p} = 4$ and $R = 2$ . Samples with the same color correspond to the same coordinate. In $f_{\\mathrm{MIMO}}^{\\mathrm{reduce}}$ , we reduce the number of unique samples in a group from $N_{p} (= 4)$ to $\\frac{N_{p}}{R} (= 2)$ by repeating each sample $R (= 2)$ times to reduce the variation in a group." + ], + "image_footnote": [], + "bbox": [ + 576, + 85, + 816, + 172 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Pixel-wise loss. We apply the pixel-wise loss (Equation 3) to each $\\hat{\\mathbf{C}}^m$ as follows.", + "bbox": [ + 498, + 279, + 890, + 308 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {p i x e l}} ^ {\\mathrm {M I M O}} = \\sum_ {m = 1} ^ {M} \\| \\hat {\\mathbf {C}} ^ {m} - \\mathbf {C} \\| _ {2} ^ {2}. \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 599, + 316, + 890, + 357 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3D consistency loss. The pixel-wise loss provides supervision in a 2D space; however, it cannot impose an explicit regularization in a 3D space. Hence, we introduce a 3D consistency loss that encourages the reformulated MIMO MLPs to produce the same colors and alpha values in the 3D space. The 3D consistency loss consists of a color 3D consistency loss $\\mathcal{L}_{\\mathrm{3D}}^{\\mathrm{color}}$ and an alpha value 3D consistency loss $\\mathcal{L}_{\\mathrm{3D}}^{\\mathrm{alpha}}$ as follows.", + "bbox": [ + 498, + 369, + 890, + 494 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {L} _ {\\mathrm {3 D}} ^ {\\mathrm {c o l o r}} = \\sum_ {m _ {1} = 1} ^ {M - 1} \\sum_ {m _ {2} = m _ {1} + 1} ^ {M} \\frac {1}{N} \\sum_ {i = 1} ^ {N} \\left[ \\mu_ {m _ {1}} ^ {m _ {2}} \\| \\mathbf {c} _ {i} ^ {m _ {1}} - \\operatorname {s g} \\left(\\mathbf {c} _ {i} ^ {m _ {2}}\\right) \\| _ {2} ^ {2} \\right. \\\\ + \\mu_ {m _ {2}} ^ {m _ {1}} \\| \\operatorname {s g} \\left(\\mathbf {c} _ {i} ^ {m _ {1}}\\right) - \\mathbf {c} _ {i} ^ {m _ {2}} \\| _ {2} ^ {2} ], \\tag {8} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 514, + 503, + 890, + 580 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {L} _ {\\mathrm {3 D}} ^ {\\mathrm {a l p h a}} = \\sum_ {m _ {1} = 1} ^ {M - 1} \\sum_ {m _ {2} = m _ {1} + 1} ^ {M} \\frac {1}{N} \\sum_ {i = 1} ^ {N} \\left[ \\mu_ {m _ {1}} ^ {m _ {2}} \\| \\alpha_ {i} ^ {m _ {1}} - \\operatorname {s g} \\left(\\alpha_ {i} ^ {m _ {2}}\\right) \\| _ {2} ^ {2} \\right. \\\\ + \\mu_ {m _ {2}} ^ {m _ {1}} \\| \\operatorname {s g} \\left(\\alpha_ {i} ^ {m _ {1}}\\right) - \\alpha_ {i} ^ {m _ {2}} \\| _ {2} ^ {2} ]. \\tag {9} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 509, + 584, + 890, + 661 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where \"sg\" indicate a stop-gradient operation. The 3D consistency loss $\\mathcal{L}_{\\mathrm{3D}}$ is calculated by $\\mathcal{L}_{\\mathrm{3D}} = \\mathcal{L}_{\\mathrm{3D}}^{\\mathrm{color}} + \\mathcal{L}_{\\mathrm{3D}}^{\\mathrm{alpha}}$ . We define $\\mu_{m_i}^{m_j}$ as $\\mu_{m_i}^{m_j} = \\frac{\\sqrt{R^{m_j}}}{\\sqrt{R^{\\max} \\sqrt{R^{m_i}}}}$ , where $R^{\\max}$ is the maximum of $R^{m}$ in $m \\in \\{1, \\ldots, M\\}$ . We use this asymmetric weight on the assumption that $\\mathbf{c}_i^m$ and $\\alpha_i^m$ with greater $R^{m}$ have lower ambiguity and are more reliable. Hence, the effect of $\\mathcal{L}_{\\mathrm{3D}}$ is reduced. We empirically investigated the importance of this effect through an ablation study as described in Section 5.3.", + "bbox": [ + 498, + 672, + 890, + 813 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Full objective. The full objective is defined as follows.", + "bbox": [ + 500, + 816, + 856, + 832 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {M I M O}} = \\mathcal {L} _ {\\text {p i x e l}} ^ {\\mathrm {M I M O}} + \\lambda \\mathcal {L} _ {\\mathrm {3 D}}, \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 607, + 840, + 890, + 861 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\lambda$ is a hyperparameter that balances the pixel-wise loss and 3D consistency loss.", + "bbox": [ + 498, + 869, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "3277", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 76, + 89, + 209, + 107 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We conducted five experiments to investigate the effectiveness of MIMO-NeRF. In the first three experiments, we conducted a comprehensive study, including an investigation of benchmark performance (Section 5.1), an investigation of the trade-off between speed and quality (Section 5.2), and ablation studies (Section 5.3). In the remaining two experiments, we examined the versatility of MIMO-NeRF by applying it to two representative fast NeRFs, including a NeRF with a sampling network, i.e., DONeRF [41] (Section 5.4), and a NeRF with alternative representations, i.e., TensoRF [9] (Section 5.5). The main results of these experiments are provided here, and detailed analyses are presented with extended results in Appendix A. The implementation details are presented in Appendix B.", + "bbox": [ + 75, + 114, + 472, + 327 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Investigation of benchmark performance", + "text_level": 1, + "bbox": [ + 76, + 337, + 426, + 353 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "First, we investigated the benchmark performance of MIMO-NeRF by applying our ideas to the original NeRF [39]. In particular, we examined three variants of MIMO-NeRF, including MIMO-NeRF-naive, which simply replaced $f_{\\mathrm{SISO}}$ (Equation 1) with $f_{\\mathrm{MIMO}}$ (Equation 4) and was trained with a standard pixel-wise loss (Equation 3). MIMO-NeRF-distill, which is a student model distilled from a pretrained standard (i.e., SISO) NeRF. During training, we used a 3D consistency loss (Equations 8 and 9) that was adjusted for knowledge distillation, in addition to the pixelwise loss. MIMO-NeRF-self, which is MIMO-NeRF that adopted the proposed self-supervised learning. We examined the performance when $N_p$ was varied within $\\{2,4,8\\}$ .", + "bbox": [ + 75, + 361, + 468, + 559 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Datasets. We investigated the benchmark performance on two commonly-used datasets. (1) Blender dataset [39] includes eight scenes, each of which consists of $360^{\\circ}$ views of complex objects at a resolution of $800 \\times 800$ pixels. We used 100 and 200 views for training and testing, respectively. (2) Local Light Field Fusion (LLFF) dataset [38, 39], which consists of eight complex real-world scenes, each of which includes 20-62 forward-facing views at $1008 \\times 756$ pixels. One-eighth of the images were used for testing, and the remainder were used for training. Where not otherwise specified, we used half-sized images following the default settings of a widely-used source code for $\\mathrm{NeRF}^5$ to better investigate the various configurations.", + "bbox": [ + 75, + 561, + 470, + 758 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Implementation. For a fair comparison, we implemented all the models with a commonly-used source code for $\\mathrm{NeRF}^5$ and trained the models using the default settings provided in the code. The number of samples was set as $N_{c} = 64$ and $N_{f} = 128$ for the Blender dataset and", + "bbox": [ + 76, + 762, + 470, + 840 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "$N_{c} = 64$ and $N_{f} = 64$ for the LLFF dataset. For MIMO-NeRF-self, we used two formulations with $R^{1} = R^{2} = 1$ when $N_{p} = 2$ , two formulations with $R^{1} = 1$ and $R^{2} = 2$ when $N_{p} = 4$ , and three formulations with $R^{1} = 1$ , $R^{2} = 2$ , and $R^{3} = 4$ when $N_{p} = 8$ . MIMO-NeRF-self was trained individually depending on $N_{p}$ . An investigation of different reformulation methods is presented in Appendix A.2. Group shifts were applied to all cases. We set $\\lambda$ to 1 and 0.4 for the Blender and LLFF datasets, respectively. The effect of $\\lambda$ is analyzed in Appendix A.3. The implementation details are presented in Appendix B.1.", + "bbox": [ + 500, + 90, + 890, + 258 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Evaluation metrics. Following the original NeRF study [39], we used the peak signal-to-noise ratio (PSNR), structural similarity index (SSIM) [64], and learned perceptual image patch similarity (LPIPS) [73] to quantitatively evaluate the image quality. To assess the calculation cost of inference and training, we report inference time (I-time) measured with an NVIDIA GeForce RTX 3080 Ti GPU and training time (T-time) measured with an NVIDIA A100-SXM4-80GB GPU. We also provide # Run $\\left(= \\frac{N_c + (N_c + N_f)}{N_p}\\right)$ and the number of parameters (# Params) as supplementary information. # Params increases in MIMO-NeRF mainly because the total dimension of the positional embeddings is increased by $N_{p}$ times according to the increase in the inputs.", + "bbox": [ + 496, + 261, + 892, + 479 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Results. From Table 1, the following is observed.", + "text_level": 1, + "bbox": [ + 500, + 482, + 828, + 497 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Image quality. MIMO-NeRF-self outperformed not only MIMO-NeRF-naive but also MIMO-NeRF-distill in most cases in terms of PSNR, SSIM, and LPIPS. We conjecture that this occurred because the joint optimization of the teacher and student networks in MIMO-NeRF-self was more effective for training than the student-only optimization in MIMO-NeRF-distill. Even MIMO-NeRF-self suffered from a trade-off between speed and quality with increasing $N_{p}$ ; however, MIMO-NeRF-self performed better than or comparably to the original NeRF when $N_{p} = 2$ . This may have occurred because the advantage of accumulating neighboring information and the disadvantage of handling the ambiguity were antagonistic in this case.", + "bbox": [ + 496, + 501, + 890, + 698 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Inference speed. All MIMO-NeRFs with the same inference procedure showed inference times improved by a factor of 1.84–5.78 with increasing $N_{p}$ .", + "bbox": [ + 496, + 700, + 893, + 748 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Training speed. MIMO-NeRF-naive achieved the fastest training because it used only a single MIMO formulation during training. MIMO-NeRF-self required more training time because it uses multiple MIMO reformulations; however, each calculation cost is low. Therefore, it did not suffer from a large increase in training time compared", + "bbox": [ + 496, + 750, + 893, + 842 + ], + "page_idx": 5 + }, + { + "type": "page_footnote", + "text": "4For simplicity and a fair comparison, we only increased the input and output of the original SISO MLP and retained the other parameters (e.g., depth and width). Hence, the increase in model size was relatively small.", + "bbox": [ + 75, + 849, + 467, + 886 + ], + "page_idx": 5 + }, + { + "type": "page_footnote", + "text": "5https://github.com/yenchenlin/nerf-pytorch", + "bbox": [ + 94, + 887, + 434, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_footnote", + "text": "For simplicity and a fair comparison, we measured the calculation time using a standard PyTorch implementation for all the models. Optimizing the implementation for faster rendering (e.g., using custom CUDA kernels) would be interesting for future research.", + "bbox": [ + 500, + 849, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "3278", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/6d6c94c144d5f5da210a7c7d082581d3aa3a90c55a2c1bb0f8ddfda4e4251a4c.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ModelNpPSNR↑SSIM↑LPIPS↓Blender # Run↓I-time↓ (s)T-time↓ (h)# Params (M)PSNR↑SSIM↑LPIPS↓LLFF # Run↓I-time↓ (s)T-time↓ (h)# Params (M)
NeRF131.040.9510.0552569.604.701.1927.720.8710.1501928.383.391.19
MIMO-NeRF-naive30.180.9440.0651285.153.091.2627.310.8600.167964.552.121.26
MIMO-NeRF-distill 2230.760.9490.0581285.159.461.2627.500.8630.169964.556.811.26
MIMO-NeRF-self331.260.9530.0541285.155.361.2627.700.8700.155964.553.971.26
MIMO-NeRF-naive28.620.9270.091642.792.021.3926.290.8240.218482.461.571.39
MIMO-NeRF-distill 4430.220.9460.065642.798.421.3927.370.8610.172482.466.251.39
MIMO-NeRF-self330.940.9500.058642.794.681.3927.510.8650.162482.463.441.39
MIMO-NeRF-naive26.340.8950.133321.661.661.6525.100.7740.284241.451.241.65
MIMO-NeRF-distill 8829.390.9370.075321.668.071.6527.010.8510.184241.455.911.65
MIMO-NeRF-self330.400.9450.065321.665.861.6526.970.8510.180241.454.431.65
", + "bbox": [ + 76, + 87, + 893, + 224 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 1. Benchmark performance of MIMO-NeRFs. MIMO-NeRF-self outperformed MIMO-NeRF-naive and MIMO-NeRF-distill in terms of PSNR, SSIM, and LPIPS in most cases with shorter training time than MIMO-NeRF-distill. All MIMO-NeRFs outperformed the original NeRF in terms of inference time owing to the reduction of # Run.", + "bbox": [ + 75, + 233, + 893, + 277 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/21677546a92471a00f99cbfe2616dfc1981e5c46a2b0b6e3d65410077252142c.jpg", + "image_caption": [ + "Figure 5. Qualitative comparison between NeRF and MIMO-NeRFs with $N_{p} = 8$ . The models were trained using full-sized images. MIMO-NeRF-naive (c) produced some artifacts owing to the ambiguity in the color and volume density of each point. MIMO-NeRF-self (d) was useful for addressing this issue, and its results were close to those of NeRF (b), while inference time were improved by a factor of 5.8." + ], + "image_footnote": [], + "bbox": [ + 76, + 297, + 472, + 489 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "with MIMO-NeRF-distill, which requires training not only a MIMO-NeRF but also a SISO NeRF.", + "bbox": [ + 75, + 645, + 468, + 675 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Summary. From these results, we found that when $N_{p} = 2$ , MIMO-NeRF-self improved the inference speed of NeRF without compromising image quality, and when $N_{p}$ was larger, there was a trade-off between speed and quality. We examine the validity of this trade-off in Section 5.2.", + "bbox": [ + 75, + 696, + 468, + 773 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Qualitative results. Figure 5 shows a qualitative comparison between NeRF, MIMO-NeRF-naive, and MIMO-NeRF-self. In this experiment, we used full-sized images to train the models and set $N_{p}$ to 8 for MIMO-NeRFs. MIMO-NeRF-naive produced some artifacts, whereas MIMO-NeRF-self adequately addressed this issue. The additional results are provided in Appendix A.6.", + "bbox": [ + 75, + 794, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/343e964da66cab51a41ba04f942d480e4286c6b42985dec995480b1c98310310.jpg", + "image_caption": [ + "Figure 6. Relationship between FLOPs and PSNR. Higher values indicate better the image quality. Faster speeds are shown to the left. MIMO-NeRF-self achieves the best trade-off between speed and quality." + ], + "image_footnote": [], + "bbox": [ + 500, + 297, + 687, + 417 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/707968fd4b819dc01b68f13bf8c8572ee630f047ae633a78e3147bb88d7c07b8.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 702, + 297, + 893, + 419 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.2. Investigation of speed-quality trade-off", + "text_level": 1, + "bbox": [ + 500, + 513, + 836, + 531 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We compared MIMO-NeRF with possible alternatives to investigate whether it achieved a good trade-off between speed and quality. In particular, we focused on methods that are general and applicable to various NeRFs, similar to MIMO-NeRF, and examined two variants, including NeRF-few, which reduced the number of samples on a ray, and NeRF-small, which reduced the number of features in the hidden layers. We adjusted the parameters such that their FLOPs were comparable to those of MIMO-NeRF.7", + "bbox": [ + 496, + 537, + 893, + 672 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Results. The relationship between the FLOPs and PSNR is plotted in Figure 6. We found that MIMO-NeRF-self obtained a better trade-off between speed and quality than NeRF-few and NeRF-small. We provide other relationships (e.g., relationships between FLOPs/inference time and PSNR/SSIM/LPIPS) in Appendix A.4. $^{8}$", + "bbox": [ + 496, + 676, + 893, + 768 + ], + "page_idx": 6 + }, + { + "type": "page_footnote", + "text": "7We tuned the models based on FLOPs because the performance of different methods for improving speed in terms of inference time may vary depending on the calculation tools used, such as GPU processor hardware. As a reference, we provide the relationship between the inference time and image quality in Appendix A.4.", + "bbox": [ + 496, + 777, + 890, + 840 + ], + "page_idx": 6 + }, + { + "type": "page_footnote", + "text": "8During training, the calculation cost of MIMO-NeRF-self was larger than those of NeRF-small and NeRF-few because multiple MIMO reformulations were used. To confirm this effect, we examined the performance of NeRF-few and NeRF-small with increasing batch sizes such that the calculation costs became almost the same as that of MIMO-NeRF-self. We", + "bbox": [ + 496, + 839, + 890, + 898 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "3279", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/fbe9a35d9858ddad96b45bf09ae13fb70b3c98acc91d37f161cceddcf0664026.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
\\(N_p\\)GSCLAWBlenderLLFF
PSNR↑SSIM↑LPIPS↓PSNR↑SSIM↑LPIPS↓
2✓30.170.9430.06727.210.8560.170
✓30.540.9450.06527.480.8650.161
✓✓31.260.9530.05427.700.8700.155
4✓✓30.840.9490.05827.390.8620.166
✓29.480.9360.07726.460.8320.206
✓✓30.870.9490.06027.440.8640.164
✓✓✓30.940.9500.05827.510.8650.162
8✓✓29.810.9410.06926.970.8510.179
✓27.390.9070.11624.290.7340.332
✓✓30.160.9420.07126.690.8430.192
✓✓✓30.400.9450.06526.970.8510.180
", + "bbox": [ + 78, + 87, + 472, + 224 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.3. Ablation studies", + "text_level": 1, + "bbox": [ + 76, + 313, + 236, + 328 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We also conducted ablation studies to better understand the performance of each element of the proposed self-supervised learning method. Specifically, we investigated the importance of group shift, 3D consistency loss, and asymmetric weights. When asymmetric weights were ablated, $\\mu_{m_i}^{m_j}$ was set to 1.", + "bbox": [ + 76, + 337, + 468, + 428 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Results. The results are listed in Table 2. We found that the full model achieved the best performance in most cases. The results validate the importance of each technique.", + "bbox": [ + 76, + 431, + 468, + 478 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4. Application to DONeRF", + "text_level": 1, + "bbox": [ + 76, + 488, + 297, + 505 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We incorporated MIMO-NeRF into DONeRF [41], a representative NeRF with a sampling network, to demonstrate that MIMO-NeRF can complement existing fast NeRFs. DONeRF uses a sampling network called a depth oracle network to select samples and calculates the colors and volume densities of the selected samples using a shading network. It handles the trade-off between speed and image quality by adjusting the number of selected samples $(N_{s})$ . We examined whether MIMO-NeRF could be used as an alternative to handle this trade-off.", + "bbox": [ + 75, + 512, + 468, + 662 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Datasets. We evaluated the performance using the DONeRF dataset [41] comprising six synthetic indoor and outdoor scenes. Each scene included 300 forward-facing views at a resolution of $800 \\times 800$ pixels. $70\\%$ , $10\\%$ , and $20\\%$ of the images were used for training, validation, and testing, respectively.", + "bbox": [ + 75, + 669, + 468, + 758 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Implementation. We implemented the models according to the source code of DONeRF and trained them using the default settings. We applied MIMO-NeRF with $N_{p} = 4$ to DONeRF-16 (i.e., DONeRF with $N_{s} = 16$ ). In the self-supervised learning process, we used two formulations with", + "bbox": [ + 75, + 763, + 468, + 839 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/0136e3bc692d9ff2194fc9bb9946f0104451ffe28614b64e8cc58262ecba94b4.jpg", + "table_caption": [ + "Table 2. Results of ablation studies. Check marks in GS, CL, and AW indicate the use of group shift, 3D consistency loss, and asymmetric weights. In $N_{p} = 2$ , asymmetric weights were not used in the full model because $R^{1} = R^{2} = 1$ . Hence, it was not ablated." + ], + "table_footnote": [], + "table_body": "
ModelPSNR↑FLIP↓# Run↓I-time↓(s)T-time↓(h)# Params(M)
DONeRF-1633.060.061170.4293.790.94
DONeRF-431.210.07050.1403.230.94
MIMO-DONeRF-16/4-naive32.300.06350.1553.260.99
MIMO-DONeRF-16/4-self32.720.06150.1553.560.99
", + "bbox": [ + 500, + 87, + 890, + 152 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 3. Comparison of quantitative scores between DONeRFs and MIMO-DONeRFs. MIMO-DONeRF-16/4-naive outperformed DONeRF-4 in terms of PSNR and FLIP with a small increase in I-time and T-time. The performance of MIMO-DONeRF-16/4-self was close to DONeRF-16 in terms of PSNR and FLIP with shorter I-time and T-time.", + "bbox": [ + 498, + 162, + 890, + 244 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "$R^1 = R^2 = 1$ and group shifts. This model is referred to as MIMO-DonNeRF-16/4. We set $\\lambda$ to 0.001. As a baseline, we examined DONeRF-4, which had the same # Run as MIMO-DonNeRF-16/4. The implementation details are presented in Appendix B.2.", + "bbox": [ + 498, + 268, + 890, + 347 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Evaluation metrics. Following the study on DONeRF [41], we assessed the image quality using the PSNR and FLIP [1]. In addition, we used the # Run, I-time, T-time, and # Params described in Section 5.1. In DONeRF, # Run was calculated as $1 + \\frac{N_s}{N_p}$ .", + "bbox": [ + 498, + 351, + 890, + 431 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Results. The results are summarized in Table 3. It is observed that MIMO-DONeRF-16/4-naive outperformed DONeRF-4 in terms of PSNR and FLIP with a small increase in I-time and T-time. MIMO-DONeRF-16/4-self enhanced the image quality with an increase in T-time, and its image quality approached that of DONeRF-16 in terms of PSNR and FLIP with faster inference and training. These results suggest that the increase in $N_{p}$ (i.e., the replacement of the SISO MLP by the MIMO MLP) can be used as an alternative to the reduction in $N_{s}$ (the number of selected samples) to obtain a better trade-off between speed and quality. A detailed analysis is presented in Appendix A.8.", + "bbox": [ + 498, + 434, + 890, + 616 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.5. Application to TensoRF", + "text_level": 1, + "bbox": [ + 500, + 628, + 718, + 643 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "A NeRF with alternative representations is another representative fast approach. To demonstrate that MIMO-NeRF is also compatible with this model, we applied it to TensoRF [9], a representative model in this category. TensoRF uses a vector-matrix decomposition to calculate the volume densities and color features and applies a SISO MLP to the color features to decode the RGB colors. The corresponding ambiguity was relatively limited because the volume densities were extracted using an explicit representation. Hence, we simply replaced the SISO MLP with a MIMO MLP without modifying the training process while prioritizing training speed. These models are denoted as MIMOTensoRF- $N_{p}$ , where $N_{p}$ was varied among $\\{2,4,8\\}$ .", + "bbox": [ + 498, + 652, + 890, + 849 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Dataset. We examined the performance of our approach on the Blender [39] and LLFF [38] datasets described in Section 5.1. Full-size images were used in this experiment.", + "bbox": [ + 498, + 854, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_footnote", + "text": "found that MIMO-NeRF-self achieved a better trade-off between speed and quality than the other variants. Detailed results are provided in Appendix A.4.", + "bbox": [ + 75, + 849, + 468, + 886 + ], + "page_idx": 7 + }, + { + "type": "page_footnote", + "text": "9https://github.com/facebookresearch/DONERF", + "bbox": [ + 94, + 887, + 433, + 898 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "3280", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/1f60f53fc21a5bbe3c84ae434e4151288a5290774f3b3b4fcb6940b50ca18482.jpg", + "table_caption": [], + "table_footnote": [ + "Table 4. Comparison of quantitative scores between TensoRF and MIMO-TensoRF. MIMO-TensoRF improved I-time and T-time while retaining PSNR and SSIM when $N_{p} \\leq 2$ and $N_{p} \\leq 4$ on the Blender and LLFF datasets, respectively." + ], + "table_body": "
ModelPSNR↑SSIM↑# Run↓I-time↓(s)T-time↓(m)# Params(M)
TensoRF33.230.9639.951.2511.5018.8
MIMO-TensoRF-233.260.9634.761.1810.8918.8
MIMO-TensoRF-432.980.9612.401.1510.6718.8
MIMO-TensoRF-832.370.9561.271.1410.5718.9
(a) Blender
ModelPSNR↑SSIM↑# Run↓I-time↓(s)T-time↓(m)# Params(M)
TensoRF26.730.837126.736.6423.4146.8
MIMO-TensoRF-226.720.83762.146.1821.6346.8
MIMO-TensoRF-426.720.83630.165.7621.1546.8
MIMO-TensoRF-826.640.83514.525.5220.6846.9
(b) LLFF
", + "bbox": [ + 78, + 85, + 468, + 237 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Implementation. We implemented the models based on the official source code of $\\mathrm{TensoRF^{10}}$ and trained all the models using the same default settings for a fair comparison. The implementation details are presented in Appendix B.3.", + "bbox": [ + 75, + 329, + 468, + 391 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Evaluation metrics. Following the study on TensoRF [9], we measured the image quality using PSNR and SSIM [64]. In addition, we used the # Run, I-time, T-time, and # Params described in Section 5.1. In TensoRF, # Run is determined adaptively for each pixel. Therefore, we report the average value.", + "bbox": [ + 75, + 393, + 468, + 484 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Results. The results are presented in Table 4. It is observed that MIMO-TensoRF improved I-time and T-time with similar image quality when $N_{p}$ was set within an adequate range (in particular, $N_{p} \\leq 2$ on the Blender dataset and $N_{p} \\leq 4$ on the LLFF dataset). These results suggest that MIMO-TensoRF can strengthen the inference and training speed of TensoRF without negative effects by adequately selecting $N_{p}$ . A detailed analysis is presented in Appendix A.9.", + "bbox": [ + 75, + 489, + 468, + 625 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Discussion", + "text_level": 1, + "bbox": [ + 76, + 638, + 191, + 655 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "The results of these experiments in various situations demonstrate that MIMO-NeRF achieved a good trade-off between speed and quality. However, we also found that the quality degradation became significant with increasing $N_{p}$ . One possible reason for this is that we did not modify the baseline network except for its input and output and did not increase the capacity of the models. It might be natural to implement a model of larger capacity to handle larger combinations of inputs and outputs. We did not adopt this strategy to ensure a fair comparison. However, searching for the best configurations considering the number of samples, the number of groups (the proposed new searching area), and the size of the model remain as a practically imperative and promising direction for further research.", + "bbox": [ + 75, + 665, + 468, + 876 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "7. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 89, + 619, + 104 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this study, we have proposed MIMO-NeRF to improve the rendering speed of NeRF. Our core idea is that of replacing the SISO MLP used in standard NeRFs with a MIMO-MLP. We have developed a novel self-supervised learning method to address the ambiguity in the color and volume density of each point without relying on pretrained models. The results of an experimental evaluation have shown that MIMO-NeRF achieves a good trade-off between speed and quality with a reasonable training time. Although we have demonstrated the versatility of MIMO-NeRF by applying it to various NeRFs, many implicit neural representations aside from NeRFs also partially or primarily use SISO MLPs. We expect our ideas to be utilized with a few modifications to speed up the execution of such models.", + "bbox": [ + 496, + 114, + 890, + 325 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 500, + 339, + 596, + 354 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Pontus Andersson, Jim Nilsson, Tomas Akenine-Möller, Magnus Oskarsson, Kalle Åström, and Mark D. Fairchild. FLIP: A difference evaluator for alternating images. Proc. ACM Comput. Graph. Interact. Tech., 3(2), 2020. 8", + "[2] Benjamin Attal, Jia-Bin Huang, Michael Zollhoefer, Johannes Kopf, and Changil Kim. Learning neural light fields with ray-space embedding networks. In CVPR, 2022. 3", + "[3] Matan Atzmon and Yaron Lipman. SAL: Sign agnostic learning of shapes from raw data. In CVPR, 2020. 3", + "[4] Jonathan T. Barron, Ben Mildenhall, Matthew Tancik, Peter Hedman, Ricardo Martin-Brualla, and Pratul P. Srinivasan. Mip-NeRF: A multiscale representation for antiailiasing neural radiance fields. In ICCV, 2021. 3", + "[5] Jonathan T. Barron, Ben Mildenhall, Dor Verbin, Pratul P. Srinivasan, and Peter Hedman. Mip-NeRF 360: Unbounded anti-aliased neural radiance fields. In CVPR, 2022. 3", + "[6] Rohan Chabra, Jan E. Lenssen, Eddy Ilg, Tanner Schmidt, Julian Straub, Steven Lovegrove, and Richard Newcombe. Deep local shapes: Learning local SDF priors for detailed 3D reconstruction. In ECCV, 2020. 3", + "[7] Eric R. Chan, Connor Z. Lin, Matthew A. Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas J. Guibas, Jonathan Tremblay, Sameh Khamis, Tero Karras, and Gordon Wetzstein. Efficient geometry-aware 3D generative adversarial networks. In CVPR, 2022. 2, 3", + "[8] Eric R. Chan, Marco Monteiro, Petr Kellnhofer, Jiajun Wu, and Gordon Wetzstein. pi-GAN: Periodic implicit generative adversarial networks for 3D-aware image synthesis. In CVPR, 2021. 3", + "[9] Anpei Chen, Zexiang Xu, Andreas Geiger, Jingyi Yu, and Hao Su. TensoRF: Tensorial radiance fields. In ECCV, 2022. 2, 3, 6, 8, 9", + "[10] Xingyu Chen, Qi Zhang, Xiaoyu Li, Yue Chen, Ying Feng, Xuan Wang, and Jue Wang. Hallucinated neural radiance fields in the wild. In CVPR, 2022. 3", + "[11] Zhiqin Chen and Hao Zhang. Learning implicit fields for generative shape modeling. In CVPR, 2019. 3" + ], + "bbox": [ + 501, + 364, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_footnote", + "text": "10https://github.com/apchenstu/TensoRF", + "bbox": [ + 89, + 886, + 385, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "3281", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[12] Julian Chibane, Aymen Mir, and Gerard Pons-Moll. Neural unsigned distance fields for implicit function learning. In NeurIPS, 2020. 3", + "[13] Yu Deng, Jiaolong Yang, Jianfeng Xiang, and Xin Tong. GRAM: Generative radiance manifolds for 3D-aware image generation. In CVPR, 2022. 3", + "[14] Jiemin Fang, Lingxi Xie, Xinggang Wang, Xiaopeng Zhang, Wenyu Liu, and Qi Tian. NeuSample: Neural sample field for efficient view synthesis. arXiv preprint arXiv:2111.15552, 2021. 2, 3", + "[15] Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, 2022. 2, 3", + "[16] Guy Gafni, Justus Thies, Michael Zollhofer, and Matthias Nießner. Dynamic neural radiance fields for monocular 4D facial avatar reconstruction. In CVPR, 2021. 3", + "[17] Stephan J. Garbin, Marek Kowalski, Matthew Johnson, Jamie Shotton, and Julien Valentin. FastNeRF: High-fidelity neural rendering at 200FPS. In ICCV, 2021. 2, 3", + "[18] Kyle Genova, Forrester Cole, Daniel Vlasic, Aaron Sarna, William T. Freeman, and Thomas Funkhouser. Learning shape templates with structured implicit functions. In ICCV, 2019. 3", + "[19] Ian J. Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In NIPS, 2014. 3", + "[20] Amos Gropp, Lior Yariv, Niv Haim, Matan Atzmon, and Yaron Lipman. Implicit geometric regularization for learning shapes. In ICML, 2020. 3", + "[21] Jiatao Gu, Lingjie Liu, Peng Wang, and Christian Theobalt. StyleNeRF: A style-based 3D-aware generator for high-resolution image synthesis. In ICLR, 2022. 3", + "[22] Peter Hedman, Pratul P. Srinivasan, Ben Mildenhall, Jonathan T. Barron, and Paul Debevec. Baking neural radiance fields for real-time view synthesis. In ICCV, 2021. 2, 3", + "[23] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. In NeurIPS, 2020. 3", + "[24] Tao Hu, Shu Liu, Yilun Chen, Tiancheng Shen, and Jiaya Jia. EfficientNeRF: Efficient neural radiance fields. In CVPR, 2022. 2, 3", + "[25] Chiyu Max Jiang, Avneesh Sud, Ameesh Makadia, Jingwei Huang, Matthias Nießner, and Thomas Funkhouser. Local implicit grid representations for 3D scenes. In CVPR, 2020. 3", + "[26] Takuhiro Kaneko. AR-NeRF: Unsupervised learning of depth and defocus effects from natural images with aperture rendering neural radiance fields. In CVPR, 2022. 3", + "[27] Andreas Kurz, Thomas Neff, Zhaoyang Lv, Michael Zollhöfer, and Markus Steinberger. AdaNeRF: Adaptive sampling for real-time rendering of neural radiance fields. In ECCV, 2022. 2, 3", + "[28] Chen-Hsuan Lin, Chaoyang Wang, and Simon Lucey. SDF-SRN: Learning signed distance 3D object reconstruction from static images. In NeurIPS, 2020. 1, 3" + ], + "bbox": [ + 78, + 90, + 468, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[29] David B. Lindell, Julien N. P. Martel, and Gordon Wetzstein. AutoInt: Automatic integration for fast neural volume rendering. In CVPR, 2021. 2, 3", + "[30] Lingjie Liu, Jiatao Gu, Kyaw Zaw Lin, Tat-Seng Chua, and Christian Theobalt. Neural sparse voxel fields. In NeurIPS, 2020. 2, 3", + "[31] Shichen Liu, Shunsuke Saito, Weikai Chen, and Hao Li. Learning to infer implicit surfaces without 3D supervision. In NeurIPS, 2019. 3", + "[32] Shaohui Liu, Yinda Zhang, Songyou Peng, Boxin Shi, Marc Pollefeys, and Zhaopeng Cui. DIST: Rendering deep implicit signed distance function with differentiable sphere tracing. In CVPR, 2020. 3", + "[33] Ricardo Martin-Brualla, Noha Radwan, Mehdi S. M. Sajjadi, Jonathan T. Barron, Alexey Dosovitskiy, and Daniel Duckworth. NeRF in the wild: Neural radiance fields for unconstrained photo collections. In CVPR, 2021. 3", + "[34] Nelson Max. Optical models for direct volume rendering. IEEE Trans. Vis. Comput. Graph., 1(2), 1995. 1, 3, 4", + "[35] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3D reconstruction in function space. In CVPR, 2019. 3", + "[36] Mateusz Michalkiewicz, Jhony K. Pontes, Dominic Jack, Mahsa Baktashmotlagh, and Anders Eriksson. Implicit surface representations as layers in neural networks. In ICCV, 2019. 3", + "[37] Ben Mildenhall, Peter Hedman, Ricardo Martin-Brualla, Pratul P. Srinivasan, and Jonathan T. Barron. NeRF in the dark: High dynamic range view synthesis from noisy raw images. In CVPR, 2022. 3", + "[38] Ben Mildenhall, Pratul P. Srinivasan, Rodrigo Ortiz-Cayon, Nima Khademi Kalantari, Ravi Ramamoorthi, Ren Ng, and Abhishek Kar. Local light field fusion: Practical view synthesis with prescriptive sampling guidelines. ACM Trans. Graph., 38(4), 2019. 6, 8", + "[39] Ben Mildenhall, Pratul P. Srinivasan, Matthew Tancik, Jonathan T. Barron, Ravi Ramamoorthi, and Ren Ng. NeRF: Representing scenes as neural radiance fields for view synthesis. In ECCV, 2020. 1, 3, 6, 8", + "[40] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Trans. Graph., 41(4), 2022. 2, 3", + "[41] Thomas Neff, Pascal Stadlbauer, Mathias Parger, Andreas Kurz, Joerg H. Mueller, Chakravarty R. Alla Chaitanya, Anton Kaplanyan, and Markus Steinberger. DONeRF: Towards real-time rendering of compact neural radiance fields using depth oracle networks. Comput. Graph. Forum, 40(4), 2021. 2, 3, 6, 8", + "[42] Michael Niemeyer and Andreas Geiger. CAMPARI: Camera-aware decomposed generative neural radiance fields. In 3DV, 2021. 3", + "[43] Michael Niemeyer and Andreas Geiger. GIRAFFE: Representing scenes as compositional generative neural feature fields. In CVPR, 2021. 3" + ], + "bbox": [ + 501, + 92, + 890, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "3282", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[44] Michael Niemeyer, Lars Mescheder, Michael Oechsle, and Andreas Geiger. Differentiable volumetric rendering: Learning implicit 3D representations without 3D supervision. In CVPR, 2020. 1, 3", + "[45] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. DeepSDF: Learning continuous signed distance functions for shape representation. In CVPR, 2019. 3", + "[46] Songyou Peng, Michael Niemeyer, Lars Mescheder, Marc Pollefeys, and Andreas Geiger. Convolutional occupancy networks. In ECCV, 2020. 3", + "[47] Martin Piala and Ronald Clark. TermiNeRF: Ray termination prediction for efficient neural rendering. In 3DV, 2021. 2, 3", + "[48] Ben Poole, Ajay Jain, Jonathan T. Barron, and Ben Mildenhall. DreamFusion: Text-to-3D using 2D diffusion. In ICLR, 2023. 3", + "[49] Albert Pumarola, Enric Corona, Gerard Pons-Moll, and Francesc Moreno-Noguer. D-NeRF: Neural radiance fields for dynamic scenes. In CVPR, 2021. 3", + "[50] Daniel Rebain, Wei Jiang, Soroosh Yazdani, Ke Li, Kwang Moo Yi, and Andrea Tagliasacchi. DeRF: Decomposed radiance fields. In CVPR, 2021. 2, 3", + "[51] Christian Reiser, Songyou Peng, Yiyi Liao, and Andreas Geiger. KiloNeRF: Speeding up neural radiance fields with thousands of tiny MLPs. In ICCV, 2021. 2, 3", + "[52] Shunsuke Saito, Zeng Huang, Ryota Natsume, Shigeo Morishima, Angjoo Kanazawa, and Hao Li. PIFu: Pixel-aligned implicit function for high-resolution clothed human digitization. In ICCV, 2019. 3", + "[53] Katja Schwarz, Yiyi Liao, Michael Niemeyer, and Andreas Geiger. GRAF: Generative radiance fields for 3D-aware image synthesis. In NeurIPS, 2020. 3", + "[54] Vincent Sitzmann, Julien Martel, Alexander Bergman, David Lindell, and Gordon Wetzstein. Implicit neural representations with periodic activation functions. In NeurIPS, 2020. 3", + "[55] Vincent Sitzmann, Semon Rezchikov, Bill Freeman, Josh Tenenbaum, and Fredo Durand. Light field networks: Neural scene representations with single-evaluation rendering. In NeurIPS, 2021. 1, 3", + "[56] Vincent Sitzmann, Michael Zollhöfer, and Gordon Wetzstein. Scene representation networks: Continuous 3D-structure-aware neural scene representations. In NeurIPS, 2019. 1, 3", + "[57] Ivan Skorokhodov, Sergey Tulyakov, Yiqun Wang, and Peter Wonka. EpiGRAF: Rethinking training of 3D GANs. In NeurIPS, 2022. 3", + "[58] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. In NeurIPS, 2019. 3", + "[59] Mohammed Suhail, Carlos Esteves, Leonid Sigal, and Ameesh Makadia. Light field neural rendering. In CVPR, 2022. 3", + "[60] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In CVPR, 2022. 2, 3" + ], + "bbox": [ + 78, + 90, + 468, + 898 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[61] Matthew Tancik, Pratul P. Srinivasan, Ben Mildenhall, Sara Fridovich-Keil, Nithin Raghavan, Utkarsh Singhal, Ravi Ramamoorthi, Jonathan T. Barron, and Ren Ng. Fourier features let networks learn high frequency functions in low dimensional domains. In NeurIPS, 2020. 3", + "[62] Dor Verbin, Peter Hedman, Ben Mildenhall, Todd Zickler, Jonathan T. Barron, and Pratul P. Srinivasan. Ref-NeRF: Structured view-dependent appearance for neural radiance fields. In CVPR, 2022. 3", + "[63] Huan Wang, Jian Ren, Zeng Huang, Kyle Olszewski, Mengei Chai, Yun Fu, and Sergey Tulyakov. R2L: Distilling neural radiance field to neural light field for efficient novel view synthesis. In ECCV, 2022. 3", + "[64] Zhou Wang, Alan C. Bovik, Hamid R. Sheikh, and Eero P. Simoncelli. Image quality assessment: From error visibility to structural similarity. IEEE Trans. Image Process., 13(4), 2004. 6, 9", + "[65] Suttisak Wizadwongsa, Pakkapon Phongthawee, Jiraphon Yenphraphai, and Supasorn Suwajanakorn. NeX: Real-time view synthesis with neural basis expansion. In CVPR, 2021. 2, 3", + "[66] Liwen Wu, Jae Yong Lee, Anand Bhattachad, Yu-Xiong Wang, and David Forsyth. DIVeR: Real-time and accurate neural radiance fields with deterministic integration for volume rendering. In CVPR, 2022. 2, 3", + "[67] Wenqi Xian, Jia-Bin Huang, Johannes Kopf, and Changil Kim. Space-time neural irradiance fields for free-viewpoint video. In CVPR, 2021. 3", + "[68] Yang Xue, Yuheng Li, Krishna Kumar Singh, and Yong Jae Lee. GIRAFFE HD: A high-resolution 3D-aware generative model. In CVPR, 2022. 3", + "[69] Lior Yariv, Yoni Kasten, Dror Moran, Meirav Galun, Matan Atzmon, Basri Ronen, and Yaron Lipman. Multiview neural surface reconstruction by disentangling geometry and appearance. In NeurIPS, 2020. 1, 3", + "[70] Alex Yu, Ruilong Li, Matthew Tancik, Hao Li, Ren Ng, and Angjoo Kanazawa. PlenOctrees for real-time rendering of neural radiance fields. In ICCV, 2021. 2, 3", + "[71] Alex Yu, Vickie Ye, Matthew Tancik, and Angjoo Kanazawa. PixelNeRF: Neural radiance fields from one or few images. In CVPR, 2021. 1, 3", + "[72] Kai Zhang, Gernot Riegler, Noah Snavely, and Vladlen Koltun. NeRF++: Analyzing and improving neural radiance fields. arXiv preprint arXiv:2010.07492, 2020.3", + "[73] Richard Zhang, Phillip Isola, Alexei A. Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In CVPR, 2018. 6" + ], + "bbox": [ + 501, + 92, + 890, + 757 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "3283", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/323ff8ab-5b3c-4603-a4d5-667546c604d5_model.json b/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/323ff8ab-5b3c-4603-a4d5-667546c604d5_model.json new file mode 100644 index 0000000000000000000000000000000000000000..9bd598f8aa45fed565d639bdec91cd4d1138a3a4 --- /dev/null +++ b/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/323ff8ab-5b3c-4603-a4d5-667546c604d5_model.json @@ -0,0 +1,2620 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.211, + 0.131, + 0.761, + 0.177 + ], + "angle": 0, + "content": "MIMO-NeRF: Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields" + }, + { + "type": "text", + "bbox": [ + 0.24, + 0.204, + 0.731, + 0.241 + ], + "angle": 0, + "content": "Takuhiro Kaneko \nNTT Communication Science Laboratories, NTT Corporation" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.274, + 0.314, + 0.29 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.307, + 0.474, + 0.685 + ], + "angle": 0, + "content": "Neural radiance fields (NeRFs) have shown impressive results for novel view synthesis. However, they depend on the repetitive use of a single-input single-output multilayer perceptron (SISO MLP) that maps 3D coordinates and view direction to the color and volume density in a sample-wise manner, which slows the rendering. We propose a multi-input multi-output NeRF (MIMO-NeRF) that reduces the number of MLPs running by replacing the SISO MLP with a MIMO MLP and conducting mappings in a group-wise manner. One notable challenge with this approach is that the color and volume density of each point can differ according to a choice of input coordinates in a group, which can lead to some notable ambiguity. We also propose a self-supervised learning method that regularizes the MIMO MLP with multiple fast reformulated MLPs to alleviate this ambiguity without using pretrained models. The results of a comprehensive experimental evaluation including comparative and ablation studies are presented to show that MIMO-NeRF obtains a good trade-off between speed and quality with a reasonable training time. We then demonstrate that MIMO-NeRF is compatible with and complementary to previous advancements in NeRFs by applying it to two representative fast NeRFs, i.e., a NeRF with a sampling network (DONeRF) and a NeRF with alternative representations (TensoRF)." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.715, + 0.21, + 0.731 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.741, + 0.47, + 0.848 + ], + "angle": 0, + "content": "Images are two-dimensional (2D) projections of three-dimensional (3D) scenes. Solving the inverse problem, that is, learning 3D representations from 2D images and synthesizing novel views, is a fundamental concern in computer vision and graphics and has been extensively studied for various applications such as photo editing, content creation, virtual reality, and environmental understanding." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.848, + 0.469, + 0.864 + ], + "angle": 0, + "content": "With the advent of implicit neural representations" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.272, + 0.697, + 0.386 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.574, + 0.39, + 0.627, + 0.403 + ], + "angle": 0, + "content": "(a) NeRF" + }, + { + "type": "image", + "bbox": [ + 0.697, + 0.272, + 0.891, + 0.386 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.713, + 0.39, + 0.874, + 0.404 + ], + "angle": 0, + "content": "(b) MIMO-NeRF (proposed)" + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.418, + 0.895, + 0.6 + ], + "angle": 0, + "content": "Figure 1. Comparison between NeRF and MIMO-NeRF (proposed). (a) A typical NeRF uses a SISO MLP that maps 3D coordinates and view direction to the color and volume density in a sample-wise manner. (b) In contrast, the proposed MIMO-NeRF uses a MIMO MLP that performs mappings in a group-wise manner. This change reduces the number of MLPs running and improves the rendering speed, but also requires addressing ambiguity in the color and volume density caused by the fact that these values are determined in a non-unique manner by a set of input coordinates that vary by viewpoint, grouping, and sampling. The main technical contribution of the present work is that of providing methods to mitigate this challenge. We demonstrate the impact of the proposed technique in Figure 2." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.627, + 0.894, + 0.779 + ], + "angle": 0, + "content": "(e.g., [56, 44, 39, 28, 69, 71, 55]), substantial advancements have been made towards addressing this problem. Neural radiance fields (NeRFs) [39] have been noted as a successful approach. A NeRF represents a scene using a continuous function that maps 3D coordinates and view direction to the color and volume density and renders a pixel by integrating the outputs on a ray using volume rendering [34]. This formulation enables NeRF to learn to synthesize geometrically consistent and high-fidelity novel views with only 2D supervision." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.895, + 0.902 + ], + "angle": 0, + "content": "Despite this advantage, a typical NeRF suffers from slow rendering because it uses a single-input single-output (SISO) MLP that calculates the RGB color and volume density in a sample-wise manner (Figure 1(a)). Although this architecture ensures the independent representation of each point, which is useful, for example, for learning view-independent volume density, its computational cost increases in proportion to the number of samples for each" + }, + { + "type": "page_footnote", + "bbox": [ + 0.078, + 0.875, + 0.468, + 0.903 + ], + "angle": 0, + "content": "1The project page is available at https://www.Kecl.ntt.co.jp/people/kaneko.takuhiro/projects/mimo-nerf/." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3273" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.152 + ], + "angle": 0, + "content": "ray (e.g., on the order of hundreds). Several methods developed to address this issue can be roughly categorized into two approaches, including (1) sample reduction and (2) alternative representations." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.153, + 0.471, + 0.349 + ], + "angle": 0, + "content": "A typical sample reduction strategy reduces the number of samples on a ray using a sampling network based on the depth [41] or density of a pretrained NeRF [47] or using a sampling network with an adaptive optimization mechanism [29, 14, 27]. These methods successfully accelerate the rendering process while retaining the quality of an image adequately. However, most of these techniques still use a SISO MLP to predict the colors and volume densities of selected samples; therefore, they still need to run MLPs many times in proportion to the number of selected samples. This issue can be alleviated by reducing the number of selected samples, although this deteriorates the quality of the synthesized images accordingly." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.349, + 0.471, + 0.546 + ], + "angle": 0, + "content": "As alternative representations, various sophisticated and faster representations such as 3D voxel grids [17, 22, 30, 66, 60], sparse voxel-based octrees [70, 15], multiplane images [65], tri-planes [7], vector-matrix decomposition [9], hashes [40], NeRF-specific structures [24], and space-wise MLPs [50, 51] have been devised. These representations contribute to achieving fast rendering while retaining image quality moderately well. However, after powerful features are extracted using alternative representations, SISO MLPs are still commonly used for the final prediction of color or volume density owing to their memory-efficient and continuous nature. Hence, part of the calculation cost still increases depending on the number of samples." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.546, + 0.47, + 0.802 + ], + "angle": 0, + "content": "Consequently, owing to its compact, continuous (i.e., resolution-free), and independent (e.g., view-independent) nature, a SISO MLP is commonly used in various NeRFs. However, as mentioned above, the calculation cost increases with the number of samples. This is not preferable when considering the improvement in rendering speed. Possible simple solutions include, for example, a reduction of the number of samples or a reduction of the size of a model with a corresponding sacrifice of image quality. However, these solutions are not necessarily the best for handling the tradeoff between quality and speed. Alternatively, we propose a multi-input multi-output NeRF (MIMO-NeRF), which is a novel variant of NeRF that represents a scene using a MIMO MLP that conducts mappings in a group-wise manner (Figure 1(b)). This modification enables a reduction in the number of MLPs running according to the number of grouped samples and consequently improves rendering speed." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.802, + 0.471, + 0.879 + ], + "angle": 0, + "content": "However, in this approach, the uniqueness of the color and volume density of each point is not ensured because they are determined not only by the coordinates of the corresponding point but also by the coordinates of the other points in a group, which vary by viewpoint, grouping, and" + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.089, + 0.889, + 0.221 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.233, + 0.892, + 0.318 + ], + "angle": 0, + "content": "Figure 2. Challenge of training MIMO-NeRF and the impact of the proposed self-supervised learning. (a) MIMO-NeRF-naive suffers from ambiguity in the color and volume density of each point and deteriorates image quality. (b) We propose self-supervised learning to address this problem without relying on a pretrained model. This technique improves image quality." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.343, + 0.893, + 0.659 + ], + "angle": 0, + "content": "sampling. This leads to some ambiguity and causes fluctuation artifacts as shown in Figure 2(a). In particular, this ambiguity can be problematic when learning a 3D representation using only 2D supervision because obtaining direct supervision that can resolve the ambiguity is difficult. One possible solution is to train a standard (i.e., SISO) NeRF first and then distill the model onto the corresponding MIMO-NeRF. However, this increases training time because both student and teacher NeRFs must be trained. Alternatively, we have also developed a novel self-supervised learning approach in which we reformulate a MIMO MLP in several ways (in particular, we use group shift (Figure 3) and variation reduction (Figure 4)) and impose a consistent regularization so that the reformulated MIMO MLPs produce the same outputs. Because each reformulated MIMO MLP can render a pixel faster than the original SISO MLP, we can prevent a large sacrifice of training time even when using multiple reformulated MIMO MLPs by adequately adjusting the reformulation configuration. Figure 2(b) shows an example of the effects of this learning scheme." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.661, + 0.892, + 0.827 + ], + "angle": 0, + "content": "We investigated the benchmark performance of MIMO-NeRF by comparing it with possible alternatives (including the distillation of a pretrained NeRF, sample reduction, and reduction of the model size). We also performed ablation studies to examine the validity of each component of the proposed self-supervised learning method. We apply MiMO-NeRF to two representative fast NeRFs, including a NeRF with a sampling network (DONeRF [41]) and a model with alternative representations (TensoRF [9]) to demonstrate that it is compatible with and complementary to previous advancements in NeRFs." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.828, + 0.891, + 0.857 + ], + "angle": 0, + "content": "The main contributions of this study are summarized as follows." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "- To speed up the rendering of NeRF, we propose MIMO-NeRF, which represents a scene using a MIMO" + }, + { + "type": "page_footnote", + "bbox": [ + 0.095, + 0.887, + 0.358, + 0.9 + ], + "angle": 0, + "content": "2We discuss this trade-off in detail in Section 5.2." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3274" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.109, + 0.092, + 0.468, + 0.121 + ], + "angle": 0, + "content": "MLP that maps the coordinates on a ray to the colors and volume densities in a group-wise manner." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.125, + 0.468, + 0.185 + ], + "angle": 0, + "content": "- We introduce novel self-supervised learning to mitigate the ambiguity in the color and volume density of each point and enable MIMO-NeRF to be trained without relying on pretrained models." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.19, + 0.468, + 0.28 + ], + "angle": 0, + "content": "- We examined the effectiveness of MIMO-NeRF through a comprehensive experimental evaluation, and the results demonstrate the versatility of MIMO-NeRF in applications to two representative fast NeRFs. We also provide more detailed analyses and extended results in the Supplementary Material." + }, + { + "type": "list", + "bbox": [ + 0.097, + 0.125, + 0.468, + 0.28 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.294, + 0.214, + 0.309 + ], + "angle": 0, + "content": "2. Related work" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.319, + 0.468, + 0.545 + ], + "angle": 0, + "content": "Implicit neural representations. Implicit neural representations have attracted attention in 3D shape [45, 35, 11, 36, 52, 18, 3, 20] and 3D scene [25, 46, 6, 12, 54] reconstructions owing to their memory-efficient, continuous (i.e., resolution-free), and 3D-aware characteristics. Although research began with explicit 3D supervision, learning implicit 3D only from 2D supervision (i.e., inverse graphics) has also been achieved by incorporating differentiable rendering [56, 31, 44, 32, 39, 28, 69, 71, 55]. In this study, we focus on NeRFs as a representative example of the latter owing to their remarkable success in synthesizing geometrically consistent and high-quality novel view. However, applying our ideas to other implicit neural representations, such as those mentioned above, remains as an interesting direction for future research." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.55, + 0.468, + 0.836 + ], + "angle": 0, + "content": "Advancements in NeRFs. Various extensions have been proposed since the emergence of NeRF. For example, representative research topics include (1) improving image quality and enhancing applicable scenes (e.g., [72, 33, 49, 16, 67, 4, 5, 37, 62, 10]), (2) incorporation into other models, e.g., deep generative models, such as generative adversarial networks (GANs) [19] and diffusion probabilistic models [58, 23] (e.g., [53, 8, 43, 42, 21, 7, 13, 68, 26, 57, 48]), and (3) accelerating NeRFs for fast inference or fast training (e.g., [41, 47, 29, 14, 27, 17, 22, 30, 66, 60, 70, 15, 65, 7, 9, 40, 24, 50, 51]). The present work falls into the third category. However, our proposed approach is complementary to previous studies, including most of the abovementioned works in all categories, because SISO MLPs have commonly been used as a partial or main network in previous studies and improving their rendering speed by replacing SISO MLPs with the proposed MIMO MLP is feasible. The results of the experimental evaluation validated this potential (Sections 5.4 and 5.5)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.84, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Acceleration of NeRFs. As discussed in Section 1, a typical NeRF is well known for its slow rendering because it use a SISO MLP. Several approaches have been developed to address this issue. These can be roughly categorized" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.485 + ], + "angle": 0, + "content": "into two approaches, including (1) sample reduction and (2) alternative representations. (1) As described in Section 1, methods that reduce the number of samples using a sampling network can improve rendering speed by replacing a SISO MLP with the proposed MIMO MLP. We validated this statement during an experiment (Section 5.4) by applying our ideas to a representative NeRF in this category (DONeRF [41]). Another common approach in the first category is to render pixels using a light-field network [55, 2, 59, 63] instead of volume rendering [34]. This approach has been shown to achieve fast rendering by running only a single MLP for a given ray. However, owing to the lack of explicit geometry-aware representations driven by the use of volume densities, these methods suffer from limitations that are not faced by a standard NeRF in terms of restrictions on applicable scenes (e.g., toy datasets [55] and forward-facing datasets [2]), a requirement for high-capacity models (e.g., a deeper MLP [63] and a transformer [59]), and the need for extra modules (e.g., metalearned priors [55], pretrained NeRFs [2, 63], or additional encoders [59]). (2) As explained in Section 1, alternative representations have the potential to accelerate the rendering speed by replacing the SISO MLP with the proposed MIMO MLP. We present an empirical investigation of this potential in Section 5.5 by incorporating MIMO-NeRF into TensoRF [9], a representative model in this category." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.487, + 0.892, + 0.668 + ], + "angle": 0, + "content": "Learning of fast NeRFs. Knowledge distillation (or baking) methods are commonly used to train fast NeRFs. In these methods, a standard NeRF is first trained and then baked to faster representations [17, 22, 24, 50, 51]. However, this approach is disadvantageous in terms of training time because two separate models must be trained, i.e., teacher and student NeRFs. As an alternative, we consider a self-supervised learning approach in which we can train a model without a large increase in training time. We examine the performance differences between the proposed self-supervised learning scheme and a knowledge distillation scheme in Section 5.1." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.679, + 0.699, + 0.695 + ], + "angle": 0, + "content": "3. Preliminaries: NeRF" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.892, + 0.796 + ], + "angle": 0, + "content": "We begin by explaining NeRFs as the basis for our model. As shown in Figure 1(a), a NeRF represents a point in a 3D space using a continuous SISO function \\( f_{\\mathrm{SISO}} \\) that maps the 3D position \\( \\mathbf{x} \\in \\mathbb{R}^3 \\) and view direction \\( \\mathbf{d} \\in \\mathbb{S}^2 \\) to the RGB color \\( \\mathbf{c}(\\mathbf{x}, \\mathbf{d}) \\in \\mathbb{R}^3 \\) and volume density \\( \\sigma(\\mathbf{x}) \\in \\mathbb{R}^+ \\) in a sample-wise manner." + }, + { + "type": "equation", + "bbox": [ + 0.527, + 0.801, + 0.892, + 0.819 + ], + "angle": 0, + "content": "\\[\nf _ {\\mathrm {S I S O}}: \\mathbb {R} ^ {3} \\times \\mathbb {S} ^ {2} \\rightarrow \\mathbb {R} ^ {3} \\times \\mathbb {R} ^ {+}, (\\mathbf {x}, \\mathbf {d}) \\mapsto (\\mathbf {c}, \\sigma). \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Specifically, positional encoding [39, 61] is applied to \\(\\mathbf{x}\\) and \\(\\mathbf{d}\\) to represent the high-frequency details of an image. Subsequently, an MLP is applied to the encoded inputs to obtain \\(\\mathbf{c}\\) and \\(\\sigma\\). For simplicity, we represent these series of processes in a unified manner as \\(f_{\\mathrm{SISO}}\\)." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3275" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.242 + ], + "angle": 0, + "content": "A NeRF is based on ray tracing, in which a camera ray is defined as \\(\\mathbf{r}(t) = \\mathbf{o} + t\\mathbf{d}\\), where \\(\\mathbf{o}\\) and \\(\\mathbf{d}\\) respectively denote the origin and direction of the camera and \\(t\\) denotes a distance from the origin. A NeRF calculates the color of each pixel \\(\\hat{\\mathbf{C}}(\\mathbf{r})\\) by integrating the colors and volume densities on a ray \\(\\mathbf{r}(t)\\) within \\(t \\in [t_n, t_f]\\) using volume rendering [34]. In implementation, the calculation of the integral is intractable; therefore, a ray is discretized into \\(N\\) points; alternatively, the following discretized formulation can be used." + }, + { + "type": "equation", + "bbox": [ + 0.12, + 0.251, + 0.47, + 0.294 + ], + "angle": 0, + "content": "\\[\n\\hat {\\mathbf {C}} (\\mathbf {r}) = \\sum_ {i = 1} ^ {N} T _ {i} \\alpha_ {i} \\mathbf {c} _ {i}, \\text {w h e r e} T _ {i} = \\prod_ {j = 1} ^ {i - 1} (1 - \\alpha_ {j}), \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.304, + 0.47, + 0.38 + ], + "angle": 0, + "content": "where the subscript \\(i\\) indicates that the variable corresponds to the \\(i\\)-th point on a ray, \\(\\alpha_{i} = 1 - \\exp (-\\sigma_{i}\\delta_{i})\\) is an alpha value, and \\(\\delta_{i} = t_{i + 1} - t_{i}\\) is the distance between the \\(i\\)-th and \\((i + 1)\\)-th points. \\(f_{\\mathrm{SISO}}\\) is optimized by minimizing the following pixel-wise loss." + }, + { + "type": "equation", + "bbox": [ + 0.184, + 0.39, + 0.469, + 0.409 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {p i x e l}} = \\| \\hat {\\mathbf {C}} (\\mathbf {r}) - \\mathbf {C} (\\mathbf {r}) \\| _ {2} ^ {2}, \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.418, + 0.47, + 0.463 + ], + "angle": 0, + "content": "where \\(\\mathbf{C}(\\mathbf{r})\\) is the ground-truth color for a ray \\(\\mathbf{r}\\). In practice, this loss is calculated for \\(\\mathbf{r} \\in \\mathcal{R}\\), where \\(\\mathcal{R}\\) denotes a set of rays in each batch." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.464, + 0.47, + 0.601 + ], + "angle": 0, + "content": "In practice, a NeRF uses coarse and fine networks. In the coarse network, a ray is discretized into \\( N_{c} \\) points using stratified sampling, whereas in the fine network, a ray is discretized into \\( N_{c} + N_{f} \\) points using hierarchical sampling in which \\( N_{f} \\) additional points are sampled according to the output of the coarse network. The two networks are optimized by minimizing \\( \\mathcal{L}_{\\mathrm{pixel}} \\) for \\( \\hat{\\mathbf{C}}(\\mathbf{r}) \\) predicted by each network. Hereafter, we omit a variable in parentheses (e.g., \\( (\\mathbf{r}) \\)) for simplicity." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.613, + 0.218, + 0.629 + ], + "angle": 0, + "content": "4. MIMO-NeRF" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.638, + 0.265, + 0.653 + ], + "angle": 0, + "content": "4.1. MIMO formulation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.661, + 0.469, + 0.812 + ], + "angle": 0, + "content": "There are several ways to group the input samples when constructing a MIMO MLP. For example, we can construct a general MLP that can accept any combination of samples in a 3D space, or we can construct a specific MLP that only accepts a group of nearby samples. In preliminary experiments (Appendix A.1), we found that the latter significantly outperformed the former because general models are more difficult to train than more specific models. Therefore, we adopted the latter in this study. In particular, we group neighboring samples on a ray as shown in Figure 1(b).3" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.812, + 0.469, + 0.843 + ], + "angle": 0, + "content": "More formally, given \\(N\\) samples on a ray, we group \\(N_{p}\\) samples from the sample nearest to the camera and create" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.092, + 0.892, + 0.122 + ], + "angle": 0, + "content": "\\(N / N_{p}\\) groups. Subsequently, we apply a MIMO function \\(f_{\\mathrm{MIMO}}\\) to each group as follows." + }, + { + "type": "equation", + "bbox": [ + 0.522, + 0.128, + 0.892, + 0.165 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} f _ {\\mathrm {M I M O}}: (\\mathbb {R} ^ {3}) ^ {N _ {p}} \\times \\mathbb {S} ^ {2} \\rightarrow (\\mathbb {R} ^ {3} \\times \\mathbb {R} ^ {+}) ^ {N _ {p}}, \\\\ \\left(\\mathbf {x} _ {i}, \\dots , \\mathbf {x} _ {j}, \\mathbf {d}\\right) \\mapsto \\left(\\mathbf {c} _ {i}, \\dots , \\mathbf {c} _ {j}, \\sigma_ {i}, \\dots , \\sigma_ {j}\\right), \\tag {4} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.171, + 0.892, + 0.277 + ], + "angle": 0, + "content": "where \\( i \\in \\{1, 1 + N_p, \\dots, 1 + N - N_p\\} \\) and \\( j = i + N_p - 1 \\). Assuming that the grouped samples are lined on a ray, we use a single direction \\( \\mathbf{d} \\) in the input of \\( f_{\\mathrm{MIMO}} \\). In this formulation, the number of MLPs running to render a pixel (#Run) is equal to the number of groups and is calculated as #Run = \\( N / N_p \\). Therefore, we can reduce the calculation cost, particularly that of #Run, by increasing \\( N_p \\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.278, + 0.892, + 0.367 + ], + "angle": 0, + "content": "In inference, the only necessary modification to a NeRF is the simple replacement of \\( f_{\\mathrm{SISO}} \\) with \\( f_{\\mathrm{MIMO}} \\) and the same volume rendering (Equation 2) and sampling scheme (i.e., stratified and hierarchical sampling) can be used. With this modification strategy, MIMO-NeRF exhibits high compatibility and complementarity with previous NeRFs." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.367, + 0.892, + 0.474 + ], + "angle": 0, + "content": "During training, \\(\\mathcal{L}_{\\mathrm{pixel}}\\) (Equation 3) can be used for \\(\\hat{\\mathbf{C}}\\) obtained using \\(f_{\\mathrm{MIMO}}\\). However, this loss does not necessarily suffice to address the ambiguity in the color and volume density of each point because this ambiguity occurs in a 3D space and the loss cannot regularize the 3D representations explicitly. Hence, we introduce self-supervised learning as discussed in subsequent sections." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.481, + 0.704, + 0.496 + ], + "angle": 0, + "content": "4.2. MIMO reformulation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.505, + 0.892, + 0.61 + ], + "angle": 0, + "content": "One possible solution to this ambiguity is to train a standard (i.e., SISO) NeRF first and then distill the model onto a corresponding MIMO-NeRF. However, this solution involves an increase in training time because it requires training not only a MIMO-NeRF but also a SISO NeRF. Consequently, this solution cannot entirely take advantage of the fast rendering of MIMO-NeRF in training." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.61, + 0.892, + 0.775 + ], + "angle": 0, + "content": "Alternatively, we reformulate a MIMO MLP in multiple ways and impose a consistent regularization to produce the same RGB colors and alpha values. Because each reformulated MIMO MLP can render a pixel faster than the original SISO MLP, we can prevent a large increase in training time even when using multiple reformulated MIMO MLPs by adequately adjusting the reformulation configuration. When implementing this idea, the question arises as to how best to reformulate a MIMO MLP. To this end, we developed two methods, including (1) group shift and (2) variation reduction." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.779, + 0.892, + 0.854 + ], + "angle": 0, + "content": "Group shift. We consider restricting this ambiguity by assessing each point in multiple ways using different groups and imposing consistency on the assessed results. More formally, we implement this by shifting groups and rewriting Equation 4 as follows." + }, + { + "type": "equation", + "bbox": [ + 0.514, + 0.86, + 0.892, + 0.898 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} f _ {\\mathrm {M I M O}} ^ {\\mathrm {s h i f t}}: (\\mathbb {R} ^ {3}) ^ {N _ {p}} \\times \\mathbb {S} ^ {2} \\to (\\mathbb {R} ^ {3} \\times \\mathbb {R} ^ {+}) ^ {N _ {p}}, \\\\ \\left(\\mathbf {x} _ {i ^ {\\prime}}, \\dots , \\mathbf {x} _ {j ^ {\\prime}}, \\mathbf {d}\\right) \\mapsto \\left(\\mathbf {c} _ {i ^ {\\prime}}, \\dots , \\mathbf {c} _ {j ^ {\\prime}}, \\sigma_ {i ^ {\\prime}}, \\dots , \\sigma_ {j ^ {\\prime}}\\right), \\tag {5} \\\\ \\end{array}\n\\]" + }, + { + "type": "page_footnote", + "bbox": [ + 0.076, + 0.851, + 0.469, + 0.901 + ], + "angle": 0, + "content": "3One possible alternative is to group near samples on different rays. However, in NeRFs, searching near points across different rays is not trivial because points are sampled unevenly via hierarchical sampling. Therefore, we simply group neighboring samples on the same ray in this study." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3276" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.078, + 0.089, + 0.473, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.195, + 0.471, + 0.252 + ], + "angle": 0, + "content": "Figure 3. Example of the group shift when \\( N_{p} = 4 \\) and \\( s = 2 \\). We shift each group by \\( s \\) toward the camera after padding \\( s \\) samples before the front sample. This procedure enables assessing each sample in multiple ways using different groups." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.275, + 0.47, + 0.398 + ], + "angle": 0, + "content": "where \\( i' \\in \\{k, k + N_p, \\ldots, k + N\\} \\) and \\( j' = i' + N_p - 1 \\). Here, \\( k \\) is the head index of the first group, which is shifted by \\( s \\in \\{1, \\ldots, N_p - 1\\} \\) toward the camera. Hence, \\( k \\in \\{2 - N_p, \\ldots, 0\\} \\). In practice, it is randomly sampled during training. More strictly, we add padding before this process to represent a sample with an index exceeding the original index, i.e., \\( i' < 1 \\) or \\( j' > N \\). For clarity, we present an example in which \\( N_p = 4 \\) and \\( s = 2 \\) in Figure 3." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.4, + 0.471, + 0.476 + ], + "angle": 0, + "content": "Variation reduction. In the original MIMO formulation, the abovementioned ambiguity is caused by \\( N_{p} \\) different input samples. To mitigate this, we consider reducing the variation in the input by replacing Equation 4 with the following." + }, + { + "type": "equation", + "bbox": [ + 0.093, + 0.486, + 0.359, + 0.505 + ], + "angle": 0, + "content": "\\[\nf _ {\\mathrm {M I M O}} ^ {\\text {r e d u c e}}: (\\mathbb {R} ^ {3}) ^ {N _ {p}} \\times \\mathbb {S} ^ {2} \\to (\\mathbb {R} ^ {3} \\times \\mathbb {R} ^ {+}) ^ {N _ {p}},\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.081, + 0.507, + 0.473, + 0.562 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\left(\\left[ \\mathbf {x} _ {i ^ {\\prime \\prime}} \\right] ^ {R}, \\ldots , \\left[ \\mathbf {x} _ {j ^ {\\prime \\prime}} \\right] ^ {R}, \\mathbf {d}\\right) \\mapsto \\left(\\mathbf {c} _ {i _ {1} ^ {\\prime \\prime}}, \\ldots , \\mathbf {c} _ {i _ {R} ^ {\\prime \\prime}}, \\ldots , \\mathbf {c} _ {j _ {1} ^ {\\prime \\prime}}, \\ldots , \\mathbf {c} _ {j _ {R} ^ {\\prime \\prime}}, \\right. \\\\ \\sigma_ {i _ {1} ^ {\\prime \\prime}}, \\dots , \\sigma_ {i _ {R} ^ {\\prime \\prime}}, \\dots , \\sigma_ {j _ {1} ^ {\\prime \\prime}}, \\dots , \\sigma_ {j _ {R} ^ {\\prime \\prime}}), \\tag {6} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.575, + 0.47, + 0.749 + ], + "angle": 0, + "content": "where \\([\\cdot ]^R\\) denotes the operation of repeating the given variable \\(R\\) times, \\(i''\\in \\{1,1 + \\frac{N_p}{R},\\ldots ,1 + N - \\frac{N_p}{R}\\}\\), and \\(j^{\\prime \\prime} = i^{\\prime \\prime} + \\frac{N_p}{R} -1\\). After applying \\(f_{\\mathrm{MIMO}}^{\\mathrm{reduce}}\\), we average \\((\\mathbf{c}_{k_1^{\\prime \\prime}},\\dots,\\mathbf{c}_{k_R^{\\prime \\prime}})\\) and \\((\\sigma_{k_1^{\\prime \\prime}},\\dots,\\sigma_{k_R^{\\prime \\prime}})\\) to obtain \\(\\mathbf{c}_{k^{\\prime \\prime}}\\) and \\(\\sigma_{k^{\\prime \\prime}}\\), where \\(k^{\\prime \\prime}\\in \\{i^{\\prime \\prime},\\dots,j^{\\prime \\prime}\\}\\). In this formulation, the mentioned ambiguity is reduced by decreasing input variation from \\(N_{p}\\) to \\(\\frac{N_p}{R}\\). Conversely, the number of MLPs running increases by factor of \\(R\\), i.e., \\(\\# \\operatorname {Run} = N / N_p\\times R\\); therefore, we need to select \\(R\\) carefully in practice to avoid a large increase in training time. For clarity, we present an example case in which \\(N_{p} = 4\\) and \\(R = 2\\) in Figure 4." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.757, + 0.241, + 0.773 + ], + "angle": 0, + "content": "4.3. MIMO objective" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Through the above processes, we obtain \\( M \\) reformulated MIMO MLPs in which we use different \\( s \\) for each MIMO MLP and set \\( R \\) such that the total number of # Run is not larger than that of the original SISO MLP. Hereafter, we use the superscript \\( m \\in \\{1, \\dots, M\\} \\) to denote the variable corresponding to the \\( m \\)-th reformulated MIMO MLP, e.g., \\( \\hat{\\mathbf{C}}^m \\) and \\( R^m \\). We train these MLPs using two loss functions, including pixel-wise and 3D consistency losses." + }, + { + "type": "image", + "bbox": [ + 0.578, + 0.087, + 0.818, + 0.173 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.186, + 0.894, + 0.256 + ], + "angle": 0, + "content": "Figure 4. Example of variation reduction when \\( N_{p} = 4 \\) and \\( R = 2 \\). Samples with the same color correspond to the same coordinate. In \\( f_{\\mathrm{MIMO}}^{\\mathrm{reduce}} \\), we reduce the number of unique samples in a group from \\( N_{p} (= 4) \\) to \\( \\frac{N_{p}}{R} (= 2) \\) by repeating each sample \\( R (= 2) \\) times to reduce the variation in a group." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.28, + 0.892, + 0.309 + ], + "angle": 0, + "content": "Pixel-wise loss. We apply the pixel-wise loss (Equation 3) to each \\(\\hat{\\mathbf{C}}^m\\) as follows." + }, + { + "type": "equation", + "bbox": [ + 0.601, + 0.317, + 0.892, + 0.358 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {p i x e l}} ^ {\\mathrm {M I M O}} = \\sum_ {m = 1} ^ {M} \\| \\hat {\\mathbf {C}} ^ {m} - \\mathbf {C} \\| _ {2} ^ {2}. \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.371, + 0.892, + 0.496 + ], + "angle": 0, + "content": "3D consistency loss. The pixel-wise loss provides supervision in a 2D space; however, it cannot impose an explicit regularization in a 3D space. Hence, we introduce a 3D consistency loss that encourages the reformulated MIMO MLPs to produce the same colors and alpha values in the 3D space. The 3D consistency loss consists of a color 3D consistency loss \\(\\mathcal{L}_{\\mathrm{3D}}^{\\mathrm{color}}\\) and an alpha value 3D consistency loss \\(\\mathcal{L}_{\\mathrm{3D}}^{\\mathrm{alpha}}\\) as follows." + }, + { + "type": "equation", + "bbox": [ + 0.515, + 0.504, + 0.892, + 0.581 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {L} _ {\\mathrm {3 D}} ^ {\\mathrm {c o l o r}} = \\sum_ {m _ {1} = 1} ^ {M - 1} \\sum_ {m _ {2} = m _ {1} + 1} ^ {M} \\frac {1}{N} \\sum_ {i = 1} ^ {N} \\left[ \\mu_ {m _ {1}} ^ {m _ {2}} \\| \\mathbf {c} _ {i} ^ {m _ {1}} - \\operatorname {s g} \\left(\\mathbf {c} _ {i} ^ {m _ {2}}\\right) \\| _ {2} ^ {2} \\right. \\\\ + \\mu_ {m _ {2}} ^ {m _ {1}} \\| \\operatorname {s g} \\left(\\mathbf {c} _ {i} ^ {m _ {1}}\\right) - \\mathbf {c} _ {i} ^ {m _ {2}} \\| _ {2} ^ {2} ], \\tag {8} \\\\ \\end{array}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.51, + 0.585, + 0.892, + 0.662 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {L} _ {\\mathrm {3 D}} ^ {\\mathrm {a l p h a}} = \\sum_ {m _ {1} = 1} ^ {M - 1} \\sum_ {m _ {2} = m _ {1} + 1} ^ {M} \\frac {1}{N} \\sum_ {i = 1} ^ {N} \\left[ \\mu_ {m _ {1}} ^ {m _ {2}} \\| \\alpha_ {i} ^ {m _ {1}} - \\operatorname {s g} \\left(\\alpha_ {i} ^ {m _ {2}}\\right) \\| _ {2} ^ {2} \\right. \\\\ + \\mu_ {m _ {2}} ^ {m _ {1}} \\| \\operatorname {s g} \\left(\\alpha_ {i} ^ {m _ {1}}\\right) - \\alpha_ {i} ^ {m _ {2}} \\| _ {2} ^ {2} ]. \\tag {9} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.673, + 0.892, + 0.814 + ], + "angle": 0, + "content": "where \"sg\" indicate a stop-gradient operation. The 3D consistency loss \\(\\mathcal{L}_{\\mathrm{3D}}\\) is calculated by \\(\\mathcal{L}_{\\mathrm{3D}} = \\mathcal{L}_{\\mathrm{3D}}^{\\mathrm{color}} + \\mathcal{L}_{\\mathrm{3D}}^{\\mathrm{alpha}}\\). We define \\(\\mu_{m_i}^{m_j}\\) as \\(\\mu_{m_i}^{m_j} = \\frac{\\sqrt{R^{m_j}}}{\\sqrt{R^{\\max} \\sqrt{R^{m_i}}}}\\), where \\(R^{\\max}\\) is the maximum of \\(R^{m}\\) in \\(m \\in \\{1, \\ldots, M\\}\\). We use this asymmetric weight on the assumption that \\(\\mathbf{c}_i^m\\) and \\(\\alpha_i^m\\) with greater \\(R^{m}\\) have lower ambiguity and are more reliable. Hence, the effect of \\(\\mathcal{L}_{\\mathrm{3D}}\\) is reduced. We empirically investigated the importance of this effect through an ablation study as described in Section 5.3." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.818, + 0.857, + 0.833 + ], + "angle": 0, + "content": "Full objective. The full objective is defined as follows." + }, + { + "type": "equation", + "bbox": [ + 0.608, + 0.842, + 0.892, + 0.862 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {M I M O}} = \\mathcal {L} _ {\\text {p i x e l}} ^ {\\mathrm {M I M O}} + \\lambda \\mathcal {L} _ {\\mathrm {3 D}}, \\tag {10}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "where \\(\\lambda\\) is a hyperparameter that balances the pixel-wise loss and 3D consistency loss." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3277" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.09, + 0.21, + 0.108 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.115, + 0.473, + 0.328 + ], + "angle": 0, + "content": "We conducted five experiments to investigate the effectiveness of MIMO-NeRF. In the first three experiments, we conducted a comprehensive study, including an investigation of benchmark performance (Section 5.1), an investigation of the trade-off between speed and quality (Section 5.2), and ablation studies (Section 5.3). In the remaining two experiments, we examined the versatility of MIMO-NeRF by applying it to two representative fast NeRFs, including a NeRF with a sampling network, i.e., DONeRF [41] (Section 5.4), and a NeRF with alternative representations, i.e., TensoRF [9] (Section 5.5). The main results of these experiments are provided here, and detailed analyses are presented with extended results in Appendix A. The implementation details are presented in Appendix B." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.338, + 0.428, + 0.354 + ], + "angle": 0, + "content": "5.1. Investigation of benchmark performance" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.362, + 0.47, + 0.56 + ], + "angle": 0, + "content": "First, we investigated the benchmark performance of MIMO-NeRF by applying our ideas to the original NeRF [39]. In particular, we examined three variants of MIMO-NeRF, including MIMO-NeRF-naive, which simply replaced \\( f_{\\mathrm{SISO}} \\) (Equation 1) with \\( f_{\\mathrm{MIMO}} \\) (Equation 4) and was trained with a standard pixel-wise loss (Equation 3). MIMO-NeRF-distill, which is a student model distilled from a pretrained standard (i.e., SISO) NeRF. During training, we used a 3D consistency loss (Equations 8 and 9) that was adjusted for knowledge distillation, in addition to the pixelwise loss. MIMO-NeRF-self, which is MIMO-NeRF that adopted the proposed self-supervised learning. We examined the performance when \\( N_p \\) was varied within \\(\\{2,4,8\\}\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.563, + 0.471, + 0.76 + ], + "angle": 0, + "content": "Datasets. We investigated the benchmark performance on two commonly-used datasets. (1) Blender dataset [39] includes eight scenes, each of which consists of \\(360^{\\circ}\\) views of complex objects at a resolution of \\(800 \\times 800\\) pixels. We used 100 and 200 views for training and testing, respectively. (2) Local Light Field Fusion (LLFF) dataset [38, 39], which consists of eight complex real-world scenes, each of which includes 20-62 forward-facing views at \\(1008 \\times 756\\) pixels. One-eighth of the images were used for testing, and the remainder were used for training. Where not otherwise specified, we used half-sized images following the default settings of a widely-used source code for \\(\\mathrm{NeRF}^5\\) to better investigate the various configurations." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.763, + 0.471, + 0.841 + ], + "angle": 0, + "content": "Implementation. For a fair comparison, we implemented all the models with a commonly-used source code for \\(\\mathrm{NeRF}^5\\) and trained the models using the default settings provided in the code. The number of samples was set as \\(N_{c} = 64\\) and \\(N_{f} = 128\\) for the Blender dataset and" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.091, + 0.892, + 0.259 + ], + "angle": 0, + "content": "\\(N_{c} = 64\\) and \\(N_{f} = 64\\) for the LLFF dataset. For MIMO-NeRF-self, we used two formulations with \\(R^{1} = R^{2} = 1\\) when \\(N_{p} = 2\\), two formulations with \\(R^{1} = 1\\) and \\(R^{2} = 2\\) when \\(N_{p} = 4\\), and three formulations with \\(R^{1} = 1\\), \\(R^{2} = 2\\), and \\(R^{3} = 4\\) when \\(N_{p} = 8\\). MIMO-NeRF-self was trained individually depending on \\(N_{p}\\). An investigation of different reformulation methods is presented in Appendix A.2. Group shifts were applied to all cases. We set \\(\\lambda\\) to 1 and 0.4 for the Blender and LLFF datasets, respectively. The effect of \\(\\lambda\\) is analyzed in Appendix A.3. The implementation details are presented in Appendix B.1." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.262, + 0.893, + 0.48 + ], + "angle": 0, + "content": "Evaluation metrics. Following the original NeRF study [39], we used the peak signal-to-noise ratio (PSNR), structural similarity index (SSIM) [64], and learned perceptual image patch similarity (LPIPS) [73] to quantitatively evaluate the image quality. To assess the calculation cost of inference and training, we report inference time (I-time) measured with an NVIDIA GeForce RTX 3080 Ti GPU and training time (T-time) measured with an NVIDIA A100-SXM4-80GB GPU. We also provide # Run \\(\\left(= \\frac{N_c + (N_c + N_f)}{N_p}\\right)\\) and the number of parameters (# Params) as supplementary information. # Params increases in MIMO-NeRF mainly because the total dimension of the positional embeddings is increased by \\(N_{p}\\) times according to the increase in the inputs." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.483, + 0.829, + 0.498 + ], + "angle": 0, + "content": "Results. From Table 1, the following is observed." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.502, + 0.892, + 0.699 + ], + "angle": 0, + "content": "Image quality. MIMO-NeRF-self outperformed not only MIMO-NeRF-naive but also MIMO-NeRF-distill in most cases in terms of PSNR, SSIM, and LPIPS. We conjecture that this occurred because the joint optimization of the teacher and student networks in MIMO-NeRF-self was more effective for training than the student-only optimization in MIMO-NeRF-distill. Even MIMO-NeRF-self suffered from a trade-off between speed and quality with increasing \\( N_{p} \\); however, MIMO-NeRF-self performed better than or comparably to the original NeRF when \\( N_{p} = 2 \\). This may have occurred because the advantage of accumulating neighboring information and the disadvantage of handling the ambiguity were antagonistic in this case." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.702, + 0.894, + 0.749 + ], + "angle": 0, + "content": "Inference speed. All MIMO-NeRFs with the same inference procedure showed inference times improved by a factor of 1.84–5.78 with increasing \\( N_{p} \\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.751, + 0.894, + 0.843 + ], + "angle": 0, + "content": "Training speed. MIMO-NeRF-naive achieved the fastest training because it used only a single MIMO formulation during training. MIMO-NeRF-self required more training time because it uses multiple MIMO reformulations; however, each calculation cost is low. Therefore, it did not suffer from a large increase in training time compared" + }, + { + "type": "page_footnote", + "bbox": [ + 0.076, + 0.85, + 0.468, + 0.887 + ], + "angle": 0, + "content": "4For simplicity and a fair comparison, we only increased the input and output of the original SISO MLP and retained the other parameters (e.g., depth and width). Hence, the increase in model size was relatively small." + }, + { + "type": "page_footnote", + "bbox": [ + 0.095, + 0.888, + 0.435, + 0.901 + ], + "angle": 0, + "content": "5https://github.com/yenchenlin/nerf-pytorch" + }, + { + "type": "list", + "bbox": [ + 0.076, + 0.85, + 0.468, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_footnote", + "bbox": [ + 0.5, + 0.851, + 0.892, + 0.901 + ], + "angle": 0, + "content": "For simplicity and a fair comparison, we measured the calculation time using a standard PyTorch implementation for all the models. Optimizing the implementation for faster rendering (e.g., using custom CUDA kernels) would be interesting for future research." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3278" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.078, + 0.088, + 0.895, + 0.226 + ], + "angle": 0, + "content": "
ModelNpPSNR↑SSIM↑LPIPS↓Blender # Run↓I-time↓ (s)T-time↓ (h)# Params (M)PSNR↑SSIM↑LPIPS↓LLFF # Run↓I-time↓ (s)T-time↓ (h)# Params (M)
NeRF131.040.9510.0552569.604.701.1927.720.8710.1501928.383.391.19
MIMO-NeRF-naive30.180.9440.0651285.153.091.2627.310.8600.167964.552.121.26
MIMO-NeRF-distill 2230.760.9490.0581285.159.461.2627.500.8630.169964.556.811.26
MIMO-NeRF-self331.260.9530.0541285.155.361.2627.700.8700.155964.553.971.26
MIMO-NeRF-naive28.620.9270.091642.792.021.3926.290.8240.218482.461.571.39
MIMO-NeRF-distill 4430.220.9460.065642.798.421.3927.370.8610.172482.466.251.39
MIMO-NeRF-self330.940.9500.058642.794.681.3927.510.8650.162482.463.441.39
MIMO-NeRF-naive26.340.8950.133321.661.661.6525.100.7740.284241.451.241.65
MIMO-NeRF-distill 8829.390.9370.075321.668.071.6527.010.8510.184241.455.911.65
MIMO-NeRF-self330.400.9450.065321.665.861.6526.970.8510.180241.454.431.65
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.234, + 0.895, + 0.278 + ], + "angle": 0, + "content": "Table 1. Benchmark performance of MIMO-NeRFs. MIMO-NeRF-self outperformed MIMO-NeRF-naive and MIMO-NeRF-distill in terms of PSNR, SSIM, and LPIPS in most cases with shorter training time than MIMO-NeRF-distill. All MIMO-NeRFs outperformed the original NeRF in terms of inference time owing to the reduction of # Run." + }, + { + "type": "image", + "bbox": [ + 0.078, + 0.298, + 0.473, + 0.491 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.505, + 0.471, + 0.603 + ], + "angle": 0, + "content": "Figure 5. Qualitative comparison between NeRF and MIMO-NeRFs with \\( N_{p} = 8 \\). The models were trained using full-sized images. MIMO-NeRF-naive (c) produced some artifacts owing to the ambiguity in the color and volume density of each point. MIMO-NeRF-self (d) was useful for addressing this issue, and its results were close to those of NeRF (b), while inference time were improved by a factor of 5.8." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.646, + 0.47, + 0.676 + ], + "angle": 0, + "content": "with MIMO-NeRF-distill, which requires training not only a MIMO-NeRF but also a SISO NeRF." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.697, + 0.47, + 0.775 + ], + "angle": 0, + "content": "Summary. From these results, we found that when \\( N_{p} = 2 \\), MIMO-NeRF-self improved the inference speed of NeRF without compromising image quality, and when \\( N_{p} \\) was larger, there was a trade-off between speed and quality. We examine the validity of this trade-off in Section 5.2." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Qualitative results. Figure 5 shows a qualitative comparison between NeRF, MIMO-NeRF-naive, and MIMO-NeRF-self. In this experiment, we used full-sized images to train the models and set \\( N_{p} \\) to 8 for MIMO-NeRFs. MIMO-NeRF-naive produced some artifacts, whereas MIMO-NeRF-self adequately addressed this issue. The additional results are provided in Appendix A.6." + }, + { + "type": "image", + "bbox": [ + 0.501, + 0.298, + 0.688, + 0.419 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.704, + 0.298, + 0.895, + 0.42 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.434, + 0.895, + 0.492 + ], + "angle": 0, + "content": "Figure 6. Relationship between FLOPs and PSNR. Higher values indicate better the image quality. Faster speeds are shown to the left. MIMO-NeRF-self achieves the best trade-off between speed and quality." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.515, + 0.837, + 0.532 + ], + "angle": 0, + "content": "5.2. Investigation of speed-quality trade-off" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.539, + 0.894, + 0.674 + ], + "angle": 0, + "content": "We compared MIMO-NeRF with possible alternatives to investigate whether it achieved a good trade-off between speed and quality. In particular, we focused on methods that are general and applicable to various NeRFs, similar to MIMO-NeRF, and examined two variants, including NeRF-few, which reduced the number of samples on a ray, and NeRF-small, which reduced the number of features in the hidden layers. We adjusted the parameters such that their FLOPs were comparable to those of MIMO-NeRF.7" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.678, + 0.894, + 0.77 + ], + "angle": 0, + "content": "Results. The relationship between the FLOPs and PSNR is plotted in Figure 6. We found that MIMO-NeRF-self obtained a better trade-off between speed and quality than NeRF-few and NeRF-small. We provide other relationships (e.g., relationships between FLOPs/inference time and PSNR/SSIM/LPIPS) in Appendix A.4.\\(^{8}\\)" + }, + { + "type": "page_footnote", + "bbox": [ + 0.498, + 0.779, + 0.892, + 0.841 + ], + "angle": 0, + "content": "7We tuned the models based on FLOPs because the performance of different methods for improving speed in terms of inference time may vary depending on the calculation tools used, such as GPU processor hardware. As a reference, we provide the relationship between the inference time and image quality in Appendix A.4." + }, + { + "type": "page_footnote", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.9 + ], + "angle": 0, + "content": "8During training, the calculation cost of MIMO-NeRF-self was larger than those of NeRF-small and NeRF-few because multiple MIMO reformulations were used. To confirm this effect, we examined the performance of NeRF-few and NeRF-small with increasing batch sizes such that the calculation costs became almost the same as that of MIMO-NeRF-self. We" + }, + { + "type": "list", + "bbox": [ + 0.498, + 0.779, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3279" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.08, + 0.088, + 0.473, + 0.226 + ], + "angle": 0, + "content": "
\\(N_p\\)GSCLAWBlenderLLFF
PSNR↑SSIM↑LPIPS↓PSNR↑SSIM↑LPIPS↓
2✓30.170.9430.06727.210.8560.170
✓30.540.9450.06527.480.8650.161
✓✓31.260.9530.05427.700.8700.155
4✓✓30.840.9490.05827.390.8620.166
✓29.480.9360.07726.460.8320.206
✓✓30.870.9490.06027.440.8640.164
✓✓✓30.940.9500.05827.510.8650.162
8✓✓29.810.9410.06926.970.8510.179
✓27.390.9070.11624.290.7340.332
✓✓30.160.9420.07126.690.8430.192
✓✓✓30.400.9450.06526.970.8510.180
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.234, + 0.47, + 0.289 + ], + "angle": 0, + "content": "Table 2. Results of ablation studies. Check marks in GS, CL, and AW indicate the use of group shift, 3D consistency loss, and asymmetric weights. In \\( N_{p} = 2 \\), asymmetric weights were not used in the full model because \\( R^{1} = R^{2} = 1 \\). Hence, it was not ablated." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.314, + 0.238, + 0.329 + ], + "angle": 0, + "content": "5.3. Ablation studies" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.338, + 0.469, + 0.429 + ], + "angle": 0, + "content": "We also conducted ablation studies to better understand the performance of each element of the proposed self-supervised learning method. Specifically, we investigated the importance of group shift, 3D consistency loss, and asymmetric weights. When asymmetric weights were ablated, \\(\\mu_{m_i}^{m_j}\\) was set to 1." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.433, + 0.469, + 0.479 + ], + "angle": 0, + "content": "Results. The results are listed in Table 2. We found that the full model achieved the best performance in most cases. The results validate the importance of each technique." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.489, + 0.298, + 0.506 + ], + "angle": 0, + "content": "5.4. Application to DONeRF" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.513, + 0.469, + 0.664 + ], + "angle": 0, + "content": "We incorporated MIMO-NeRF into DONeRF [41], a representative NeRF with a sampling network, to demonstrate that MIMO-NeRF can complement existing fast NeRFs. DONeRF uses a sampling network called a depth oracle network to select samples and calculates the colors and volume densities of the selected samples using a shading network. It handles the trade-off between speed and image quality by adjusting the number of selected samples \\((N_{s})\\). We examined whether MIMO-NeRF could be used as an alternative to handle this trade-off." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.67, + 0.469, + 0.76 + ], + "angle": 0, + "content": "Datasets. We evaluated the performance using the DONeRF dataset [41] comprising six synthetic indoor and outdoor scenes. Each scene included 300 forward-facing views at a resolution of \\(800 \\times 800\\) pixels. \\(70\\%\\), \\(10\\%\\), and \\(20\\%\\) of the images were used for training, validation, and testing, respectively." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.469, + 0.84 + ], + "angle": 0, + "content": "Implementation. We implemented the models according to the source code of DONeRF and trained them using the default settings. We applied MIMO-NeRF with \\( N_{p} = 4 \\) to DONeRF-16 (i.e., DONeRF with \\( N_{s} = 16 \\)). In the self-supervised learning process, we used two formulations with" + }, + { + "type": "table", + "bbox": [ + 0.501, + 0.088, + 0.892, + 0.153 + ], + "angle": 0, + "content": "
ModelPSNR↑FLIP↓# Run↓I-time↓(s)T-time↓(h)# Params(M)
DONeRF-1633.060.061170.4293.790.94
DONeRF-431.210.07050.1403.230.94
MIMO-DONeRF-16/4-naive32.300.06350.1553.260.99
MIMO-DONeRF-16/4-self32.720.06150.1553.560.99
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.163, + 0.892, + 0.245 + ], + "angle": 0, + "content": "Table 3. Comparison of quantitative scores between DONeRFs and MIMO-DONeRFs. MIMO-DONeRF-16/4-naive outperformed DONeRF-4 in terms of PSNR and FLIP with a small increase in I-time and T-time. The performance of MIMO-DONeRF-16/4-self was close to DONeRF-16 in terms of PSNR and FLIP with shorter I-time and T-time." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.27, + 0.892, + 0.348 + ], + "angle": 0, + "content": "\\(R^1 = R^2 = 1\\) and group shifts. This model is referred to as MIMO-DonNeRF-16/4. We set \\(\\lambda\\) to 0.001. As a baseline, we examined DONeRF-4, which had the same # Run as MIMO-DonNeRF-16/4. The implementation details are presented in Appendix B.2." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.352, + 0.892, + 0.432 + ], + "angle": 0, + "content": "Evaluation metrics. Following the study on DONeRF [41], we assessed the image quality using the PSNR and FLIP [1]. In addition, we used the # Run, I-time, T-time, and # Params described in Section 5.1. In DONeRF, # Run was calculated as \\(1 + \\frac{N_s}{N_p}\\)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.435, + 0.892, + 0.617 + ], + "angle": 0, + "content": "Results. The results are summarized in Table 3. It is observed that MIMO-DONeRF-16/4-naive outperformed DONeRF-4 in terms of PSNR and FLIP with a small increase in I-time and T-time. MIMO-DONeRF-16/4-self enhanced the image quality with an increase in T-time, and its image quality approached that of DONeRF-16 in terms of PSNR and FLIP with faster inference and training. These results suggest that the increase in \\( N_{p} \\) (i.e., the replacement of the SISO MLP by the MIMO MLP) can be used as an alternative to the reduction in \\( N_{s} \\) (the number of selected samples) to obtain a better trade-off between speed and quality. A detailed analysis is presented in Appendix A.8." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.629, + 0.719, + 0.645 + ], + "angle": 0, + "content": "5.5. Application to TensoRF" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.654, + 0.892, + 0.851 + ], + "angle": 0, + "content": "A NeRF with alternative representations is another representative fast approach. To demonstrate that MIMO-NeRF is also compatible with this model, we applied it to TensoRF [9], a representative model in this category. TensoRF uses a vector-matrix decomposition to calculate the volume densities and color features and applies a SISO MLP to the color features to decode the RGB colors. The corresponding ambiguity was relatively limited because the volume densities were extracted using an explicit representation. Hence, we simply replaced the SISO MLP with a MIMO MLP without modifying the training process while prioritizing training speed. These models are denoted as MIMOTensoRF-\\(N_{p}\\), where \\(N_{p}\\) was varied among \\(\\{2,4,8\\}\\)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Dataset. We examined the performance of our approach on the Blender [39] and LLFF [38] datasets described in Section 5.1. Full-size images were used in this experiment." + }, + { + "type": "page_footnote", + "bbox": [ + 0.076, + 0.85, + 0.469, + 0.887 + ], + "angle": 0, + "content": "found that MIMO-NeRF-self achieved a better trade-off between speed and quality than the other variants. Detailed results are provided in Appendix A.4." + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.888, + 0.434, + 0.9 + ], + "angle": 0, + "content": "9https://github.com/facebookresearch/DONERF" + }, + { + "type": "list", + "bbox": [ + 0.076, + 0.85, + 0.469, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "3280" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.079, + 0.087, + 0.47, + 0.238 + ], + "angle": 0, + "content": "
ModelPSNR↑SSIM↑# Run↓I-time↓(s)T-time↓(m)# Params(M)
TensoRF33.230.9639.951.2511.5018.8
MIMO-TensoRF-233.260.9634.761.1810.8918.8
MIMO-TensoRF-432.980.9612.401.1510.6718.8
MIMO-TensoRF-832.370.9561.271.1410.5718.9
(a) Blender
ModelPSNR↑SSIM↑# Run↓I-time↓(s)T-time↓(m)# Params(M)
TensoRF26.730.837126.736.6423.4146.8
MIMO-TensoRF-226.720.83762.146.1821.6346.8
MIMO-TensoRF-426.720.83630.165.7621.1546.8
MIMO-TensoRF-826.640.83514.525.5220.6846.9
(b) LLFF
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.076, + 0.249, + 0.47, + 0.306 + ], + "angle": 0, + "content": "Table 4. Comparison of quantitative scores between TensoRF and MIMO-TensoRF. MIMO-TensoRF improved I-time and T-time while retaining PSNR and SSIM when \\( N_{p} \\leq 2 \\) and \\( N_{p} \\leq 4 \\) on the Blender and LLFF datasets, respectively." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.33, + 0.469, + 0.392 + ], + "angle": 0, + "content": "Implementation. We implemented the models based on the official source code of \\(\\mathrm{TensoRF^{10}}\\) and trained all the models using the same default settings for a fair comparison. The implementation details are presented in Appendix B.3." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.395, + 0.469, + 0.485 + ], + "angle": 0, + "content": "Evaluation metrics. Following the study on TensoRF [9], we measured the image quality using PSNR and SSIM [64]. In addition, we used the # Run, I-time, T-time, and # Params described in Section 5.1. In TensoRF, # Run is determined adaptively for each pixel. Therefore, we report the average value." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.49, + 0.469, + 0.626 + ], + "angle": 0, + "content": "Results. The results are presented in Table 4. It is observed that MIMO-TensoRF improved I-time and T-time with similar image quality when \\( N_{p} \\) was set within an adequate range (in particular, \\( N_{p} \\leq 2 \\) on the Blender dataset and \\( N_{p} \\leq 4 \\) on the LLFF dataset). These results suggest that MIMO-TensoRF can strengthen the inference and training speed of TensoRF without negative effects by adequately selecting \\( N_{p} \\). A detailed analysis is presented in Appendix A.9." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.64, + 0.192, + 0.656 + ], + "angle": 0, + "content": "6. Discussion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.666, + 0.47, + 0.877 + ], + "angle": 0, + "content": "The results of these experiments in various situations demonstrate that MIMO-NeRF achieved a good trade-off between speed and quality. However, we also found that the quality degradation became significant with increasing \\( N_{p} \\). One possible reason for this is that we did not modify the baseline network except for its input and output and did not increase the capacity of the models. It might be natural to implement a model of larger capacity to handle larger combinations of inputs and outputs. We did not adopt this strategy to ensure a fair comparison. However, searching for the best configurations considering the number of samples, the number of groups (the proposed new searching area), and the size of the model remain as a practically imperative and promising direction for further research." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.09, + 0.62, + 0.106 + ], + "angle": 0, + "content": "7. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.115, + 0.892, + 0.327 + ], + "angle": 0, + "content": "In this study, we have proposed MIMO-NeRF to improve the rendering speed of NeRF. Our core idea is that of replacing the SISO MLP used in standard NeRFs with a MIMO-MLP. We have developed a novel self-supervised learning method to address the ambiguity in the color and volume density of each point without relying on pretrained models. The results of an experimental evaluation have shown that MIMO-NeRF achieves a good trade-off between speed and quality with a reasonable training time. Although we have demonstrated the versatility of MIMO-NeRF by applying it to various NeRFs, many implicit neural representations aside from NeRFs also partially or primarily use SISO MLPs. We expect our ideas to be utilized with a few modifications to speed up the execution of such models." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.34, + 0.597, + 0.355 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.508, + 0.365, + 0.891, + 0.42 + ], + "angle": 0, + "content": "[1] Pontus Andersson, Jim Nilsson, Tomas Akenine-Möller, Magnus Oskarsson, Kalle Åström, and Mark D. Fairchild. FLIP: A difference evaluator for alternating images. Proc. ACM Comput. Graph. Interact. Tech., 3(2), 2020. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.422, + 0.892, + 0.463 + ], + "angle": 0, + "content": "[2] Benjamin Attal, Jia-Bin Huang, Michael Zollhoefer, Johannes Kopf, and Changil Kim. Learning neural light fields with ray-space embedding networks. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.464, + 0.892, + 0.491 + ], + "angle": 0, + "content": "[3] Matan Atzmon and Yaron Lipman. SAL: Sign agnostic learning of shapes from raw data. In CVPR, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.493, + 0.892, + 0.547 + ], + "angle": 0, + "content": "[4] Jonathan T. Barron, Ben Mildenhall, Matthew Tancik, Peter Hedman, Ricardo Martin-Brualla, and Pratul P. Srinivasan. Mip-NeRF: A multiscale representation for antiailiasing neural radiance fields. In ICCV, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.549, + 0.892, + 0.589 + ], + "angle": 0, + "content": "[5] Jonathan T. Barron, Ben Mildenhall, Dor Verbin, Pratul P. Srinivasan, and Peter Hedman. Mip-NeRF 360: Unbounded anti-aliased neural radiance fields. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.591, + 0.892, + 0.646 + ], + "angle": 0, + "content": "[6] Rohan Chabra, Jan E. Lenssen, Eddy Ilg, Tanner Schmidt, Julian Straub, Steven Lovegrove, and Richard Newcombe. Deep local shapes: Learning local SDF priors for detailed 3D reconstruction. In ECCV, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.648, + 0.892, + 0.729 + ], + "angle": 0, + "content": "[7] Eric R. Chan, Connor Z. Lin, Matthew A. Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas J. Guibas, Jonathan Tremblay, Sameh Khamis, Tero Karras, and Gordon Wetzstein. Efficient geometry-aware 3D generative adversarial networks. In CVPR, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.732, + 0.892, + 0.786 + ], + "angle": 0, + "content": "[8] Eric R. Chan, Marco Monteiro, Petr Kellnhofer, Jiajun Wu, and Gordon Wetzstein. pi-GAN: Periodic implicit generative adversarial networks for 3D-aware image synthesis. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.788, + 0.892, + 0.828 + ], + "angle": 0, + "content": "[9] Anpei Chen, Zexiang Xu, Andreas Geiger, Jingyi Yu, and Hao Su. TensoRF: Tensorial radiance fields. In ECCV, 2022. 2, 3, 6, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.831, + 0.892, + 0.871 + ], + "angle": 0, + "content": "[10] Xingyu Chen, Qi Zhang, Xiaoyu Li, Yue Chen, Ying Feng, Xuan Wang, and Jue Wang. Hallucinated neural radiance fields in the wild. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.873, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[11] Zhiqin Chen and Hao Zhang. Learning implicit fields for generative shape modeling. In CVPR, 2019. 3" + }, + { + "type": "list", + "bbox": [ + 0.502, + 0.365, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_footnote", + "bbox": [ + 0.091, + 0.887, + 0.387, + 0.9 + ], + "angle": 0, + "content": "10https://github.com/apchenstu/TensoRF" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "3281" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.133 + ], + "angle": 0, + "content": "[12] Julian Chibane, Aymen Mir, and Gerard Pons-Moll. Neural unsigned distance fields for implicit function learning. In NeurIPS, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.136, + 0.468, + 0.177 + ], + "angle": 0, + "content": "[13] Yu Deng, Jiaolong Yang, Jianfeng Xiang, and Xin Tong. GRAM: Generative radiance manifolds for 3D-aware image generation. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.179, + 0.468, + 0.233 + ], + "angle": 0, + "content": "[14] Jiemin Fang, Lingxi Xie, Xinggang Wang, Xiaopeng Zhang, Wenyu Liu, and Qi Tian. NeuSample: Neural sample field for efficient view synthesis. arXiv preprint arXiv:2111.15552, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.235, + 0.468, + 0.288 + ], + "angle": 0, + "content": "[15] Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.292, + 0.468, + 0.332 + ], + "angle": 0, + "content": "[16] Guy Gafni, Justus Thies, Michael Zollhofer, and Matthias Nießner. Dynamic neural radiance fields for monocular 4D facial avatar reconstruction. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.334, + 0.468, + 0.375 + ], + "angle": 0, + "content": "[17] Stephan J. Garbin, Marek Kowalski, Matthew Johnson, Jamie Shotton, and Julien Valentin. FastNeRF: High-fidelity neural rendering at 200FPS. In ICCV, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.377, + 0.468, + 0.431 + ], + "angle": 0, + "content": "[18] Kyle Genova, Forrester Cole, Daniel Vlasic, Aaron Sarna, William T. Freeman, and Thomas Funkhouser. Learning shape templates with structured implicit functions. In ICCV, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.434, + 0.468, + 0.487 + ], + "angle": 0, + "content": "[19] Ian J. Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In NIPS, 2014. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.49, + 0.468, + 0.531 + ], + "angle": 0, + "content": "[20] Amos Gropp, Lior Yariv, Niv Haim, Matan Atzmon, and Yaron Lipman. Implicit geometric regularization for learning shapes. In ICML, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.533, + 0.468, + 0.574 + ], + "angle": 0, + "content": "[21] Jiatao Gu, Lingjie Liu, Peng Wang, and Christian Theobalt. StyleNeRF: A style-based 3D-aware generator for high-resolution image synthesis. In ICLR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.576, + 0.468, + 0.629 + ], + "angle": 0, + "content": "[22] Peter Hedman, Pratul P. Srinivasan, Ben Mildenhall, Jonathan T. Barron, and Paul Debevec. Baking neural radiance fields for real-time view synthesis. In ICCV, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.633, + 0.468, + 0.659 + ], + "angle": 0, + "content": "[23] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. In NeurIPS, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.661, + 0.468, + 0.701 + ], + "angle": 0, + "content": "[24] Tao Hu, Shu Liu, Yilun Chen, Tiancheng Shen, and Jiaya Jia. EfficientNeRF: Efficient neural radiance fields. In CVPR, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.704, + 0.468, + 0.758 + ], + "angle": 0, + "content": "[25] Chiyu Max Jiang, Avneesh Sud, Ameesh Makadia, Jingwei Huang, Matthias Nießner, and Thomas Funkhouser. Local implicit grid representations for 3D scenes. In CVPR, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.761, + 0.468, + 0.802 + ], + "angle": 0, + "content": "[26] Takuhiro Kaneko. AR-NeRF: Unsupervised learning of depth and defocus effects from natural images with aperture rendering neural radiance fields. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.804, + 0.468, + 0.857 + ], + "angle": 0, + "content": "[27] Andreas Kurz, Thomas Neff, Zhaoyang Lv, Michael Zollhöfer, and Markus Steinberger. AdaNeRF: Adaptive sampling for real-time rendering of neural radiance fields. In ECCV, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.86, + 0.468, + 0.901 + ], + "angle": 0, + "content": "[28] Chen-Hsuan Lin, Chaoyang Wang, and Simon Lucey. SDF-SRN: Learning signed distance 3D object reconstruction from static images. In NeurIPS, 2020. 1, 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[29] David B. Lindell, Julien N. P. Martel, and Gordon Wetzstein. AutoInt: Automatic integration for fast neural volume rendering. In CVPR, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.137, + 0.892, + 0.177 + ], + "angle": 0, + "content": "[30] Lingjie Liu, Jiatao Gu, Kyaw Zaw Lin, Tat-Seng Chua, and Christian Theobalt. Neural sparse voxel fields. In NeurIPS, 2020. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.181, + 0.892, + 0.221 + ], + "angle": 0, + "content": "[31] Shichen Liu, Shunsuke Saito, Weikai Chen, and Hao Li. Learning to infer implicit surfaces without 3D supervision. In NeurIPS, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.225, + 0.892, + 0.279 + ], + "angle": 0, + "content": "[32] Shaohui Liu, Yinda Zhang, Songyou Peng, Boxin Shi, Marc Pollefeys, and Zhaopeng Cui. DIST: Rendering deep implicit signed distance function with differentiable sphere tracing. In CVPR, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.283, + 0.892, + 0.337 + ], + "angle": 0, + "content": "[33] Ricardo Martin-Brualla, Noha Radwan, Mehdi S. M. Sajjadi, Jonathan T. Barron, Alexey Dosovitskiy, and Daniel Duckworth. NeRF in the wild: Neural radiance fields for unconstrained photo collections. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.341, + 0.892, + 0.368 + ], + "angle": 0, + "content": "[34] Nelson Max. Optical models for direct volume rendering. IEEE Trans. Vis. Comput. Graph., 1(2), 1995. 1, 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.371, + 0.892, + 0.424 + ], + "angle": 0, + "content": "[35] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3D reconstruction in function space. In CVPR, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.428, + 0.892, + 0.481 + ], + "angle": 0, + "content": "[36] Mateusz Michalkiewicz, Jhony K. Pontes, Dominic Jack, Mahsa Baktashmotlagh, and Anders Eriksson. Implicit surface representations as layers in neural networks. In ICCV, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.486, + 0.892, + 0.54 + ], + "angle": 0, + "content": "[37] Ben Mildenhall, Peter Hedman, Ricardo Martin-Brualla, Pratul P. Srinivasan, and Jonathan T. Barron. NeRF in the dark: High dynamic range view synthesis from noisy raw images. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.544, + 0.892, + 0.612 + ], + "angle": 0, + "content": "[38] Ben Mildenhall, Pratul P. Srinivasan, Rodrigo Ortiz-Cayon, Nima Khademi Kalantari, Ravi Ramamoorthi, Ren Ng, and Abhishek Kar. Local light field fusion: Practical view synthesis with prescriptive sampling guidelines. ACM Trans. Graph., 38(4), 2019. 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.615, + 0.892, + 0.669 + ], + "angle": 0, + "content": "[39] Ben Mildenhall, Pratul P. Srinivasan, Matthew Tancik, Jonathan T. Barron, Ravi Ramamoorthi, and Ren Ng. NeRF: Representing scenes as neural radiance fields for view synthesis. In ECCV, 2020. 1, 3, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.673, + 0.892, + 0.726 + ], + "angle": 0, + "content": "[40] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Trans. Graph., 41(4), 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.731, + 0.892, + 0.812 + ], + "angle": 0, + "content": "[41] Thomas Neff, Pascal Stadlbauer, Mathias Parger, Andreas Kurz, Joerg H. Mueller, Chakravarty R. Alla Chaitanya, Anton Kaplanyan, and Markus Steinberger. DONeRF: Towards real-time rendering of compact neural radiance fields using depth oracle networks. Comput. Graph. Forum, 40(4), 2021. 2, 3, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.816, + 0.892, + 0.856 + ], + "angle": 0, + "content": "[42] Michael Niemeyer and Andreas Geiger. CAMPARI: Camera-aware decomposed generative neural radiance fields. In 3DV, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.86, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[43] Michael Niemeyer and Andreas Geiger. GIRAFFE: Representing scenes as compositional generative neural feature fields. In CVPR, 2021. 3" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.956 + ], + "angle": 0, + "content": "3282" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[44] Michael Niemeyer, Lars Mescheder, Michael Oechsle, and Andreas Geiger. Differentiable volumetric rendering: Learning implicit 3D representations without 3D supervision. In CVPR, 2020. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.149, + 0.47, + 0.204 + ], + "angle": 0, + "content": "[45] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. DeepSDF: Learning continuous signed distance functions for shape representation. In CVPR, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.206, + 0.469, + 0.247 + ], + "angle": 0, + "content": "[46] Songyou Peng, Michael Niemeyer, Lars Mescheder, Marc Pollefeys, and Andreas Geiger. Convolutional occupancy networks. In ECCV, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.249, + 0.469, + 0.288 + ], + "angle": 0, + "content": "[47] Martin Piala and Ronald Clark. TermiNeRF: Ray termination prediction for efficient neural rendering. In 3DV, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.291, + 0.469, + 0.331 + ], + "angle": 0, + "content": "[48] Ben Poole, Ajay Jain, Jonathan T. Barron, and Ben Mildenhall. DreamFusion: Text-to-3D using 2D diffusion. In ICLR, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.334, + 0.469, + 0.375 + ], + "angle": 0, + "content": "[49] Albert Pumarola, Enric Corona, Gerard Pons-Moll, and Francesc Moreno-Noguer. D-NeRF: Neural radiance fields for dynamic scenes. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.377, + 0.469, + 0.418 + ], + "angle": 0, + "content": "[50] Daniel Rebain, Wei Jiang, Soroosh Yazdani, Ke Li, Kwang Moo Yi, and Andrea Tagliasacchi. DeRF: Decomposed radiance fields. In CVPR, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.42, + 0.469, + 0.46 + ], + "angle": 0, + "content": "[51] Christian Reiser, Songyou Peng, Yiyi Liao, and Andreas Geiger. KiloNeRF: Speeding up neural radiance fields with thousands of tiny MLPs. In ICCV, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.462, + 0.469, + 0.517 + ], + "angle": 0, + "content": "[52] Shunsuke Saito, Zeng Huang, Ryota Natsume, Shigeo Morishima, Angjoo Kanazawa, and Hao Li. PIFu: Pixel-aligned implicit function for high-resolution clothed human digitization. In ICCV, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.519, + 0.469, + 0.56 + ], + "angle": 0, + "content": "[53] Katja Schwarz, Yiyi Liao, Michael Niemeyer, and Andreas Geiger. GRAF: Generative radiance fields for 3D-aware image synthesis. In NeurIPS, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.562, + 0.469, + 0.615 + ], + "angle": 0, + "content": "[54] Vincent Sitzmann, Julien Martel, Alexander Bergman, David Lindell, and Gordon Wetzstein. Implicit neural representations with periodic activation functions. In NeurIPS, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.618, + 0.469, + 0.673 + ], + "angle": 0, + "content": "[55] Vincent Sitzmann, Semon Rezchikov, Bill Freeman, Josh Tenenbaum, and Fredo Durand. Light field networks: Neural scene representations with single-evaluation rendering. In NeurIPS, 2021. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.675, + 0.469, + 0.729 + ], + "angle": 0, + "content": "[56] Vincent Sitzmann, Michael Zollhöfer, and Gordon Wetzstein. Scene representation networks: Continuous 3D-structure-aware neural scene representations. In NeurIPS, 2019. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.731, + 0.469, + 0.772 + ], + "angle": 0, + "content": "[57] Ivan Skorokhodov, Sergey Tulyakov, Yiqun Wang, and Peter Wonka. EpiGRAF: Rethinking training of 3D GANs. In NeurIPS, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.774, + 0.469, + 0.814 + ], + "angle": 0, + "content": "[58] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. In NeurIPS, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.817, + 0.469, + 0.857 + ], + "angle": 0, + "content": "[59] Mohammed Suhail, Carlos Esteves, Leonid Sigal, and Ameesh Makadia. Light field neural rendering. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.859, + 0.469, + 0.9 + ], + "angle": 0, + "content": "[60] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In CVPR, 2022. 2, 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.161 + ], + "angle": 0, + "content": "[61] Matthew Tancik, Pratul P. Srinivasan, Ben Mildenhall, Sara Fridovich-Keil, Nithin Raghavan, Utkarsh Singhal, Ravi Ramamoorthi, Jonathan T. Barron, and Ren Ng. Fourier features let networks learn high frequency functions in low dimensional domains. In NeurIPS, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.164, + 0.892, + 0.218 + ], + "angle": 0, + "content": "[62] Dor Verbin, Peter Hedman, Ben Mildenhall, Todd Zickler, Jonathan T. Barron, and Pratul P. Srinivasan. Ref-NeRF: Structured view-dependent appearance for neural radiance fields. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.22, + 0.892, + 0.275 + ], + "angle": 0, + "content": "[63] Huan Wang, Jian Ren, Zeng Huang, Kyle Olszewski, Mengei Chai, Yun Fu, and Sergey Tulyakov. R2L: Distilling neural radiance field to neural light field for efficient novel view synthesis. In ECCV, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.277, + 0.892, + 0.33 + ], + "angle": 0, + "content": "[64] Zhou Wang, Alan C. Bovik, Hamid R. Sheikh, and Eero P. Simoncelli. Image quality assessment: From error visibility to structural similarity. IEEE Trans. Image Process., 13(4), 2004. 6, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.333, + 0.892, + 0.387 + ], + "angle": 0, + "content": "[65] Suttisak Wizadwongsa, Pakkapon Phongthawee, Jiraphon Yenphraphai, and Supasorn Suwajanakorn. NeX: Real-time view synthesis with neural basis expansion. In CVPR, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.39, + 0.892, + 0.445 + ], + "angle": 0, + "content": "[66] Liwen Wu, Jae Yong Lee, Anand Bhattachad, Yu-Xiong Wang, and David Forsyth. DIVeR: Real-time and accurate neural radiance fields with deterministic integration for volume rendering. In CVPR, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.447, + 0.892, + 0.487 + ], + "angle": 0, + "content": "[67] Wenqi Xian, Jia-Bin Huang, Johannes Kopf, and Changil Kim. Space-time neural irradiance fields for free-viewpoint video. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.489, + 0.892, + 0.53 + ], + "angle": 0, + "content": "[68] Yang Xue, Yuheng Li, Krishna Kumar Singh, and Yong Jae Lee. GIRAFFE HD: A high-resolution 3D-aware generative model. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.532, + 0.892, + 0.587 + ], + "angle": 0, + "content": "[69] Lior Yariv, Yoni Kasten, Dror Moran, Meirav Galun, Matan Atzmon, Basri Ronen, and Yaron Lipman. Multiview neural surface reconstruction by disentangling geometry and appearance. In NeurIPS, 2020. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.589, + 0.892, + 0.629 + ], + "angle": 0, + "content": "[70] Alex Yu, Ruilong Li, Matthew Tancik, Hao Li, Ren Ng, and Angjoo Kanazawa. PlenOctrees for real-time rendering of neural radiance fields. In ICCV, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.631, + 0.892, + 0.672 + ], + "angle": 0, + "content": "[71] Alex Yu, Vickie Ye, Matthew Tancik, and Angjoo Kanazawa. PixelNeRF: Neural radiance fields from one or few images. In CVPR, 2021. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.674, + 0.892, + 0.715 + ], + "angle": 0, + "content": "[72] Kai Zhang, Gernot Riegler, Noah Snavely, and Vladlen Koltun. NeRF++: Analyzing and improving neural radiance fields. arXiv preprint arXiv:2010.07492, 2020.3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.717, + 0.892, + 0.758 + ], + "angle": 0, + "content": "[73] Richard Zhang, Phillip Isola, Alexei A. Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In CVPR, 2018. 6" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.758 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3283" + } + ] +] \ No newline at end of file diff --git a/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/323ff8ab-5b3c-4603-a4d5-667546c604d5_origin.pdf b/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/323ff8ab-5b3c-4603-a4d5-667546c604d5_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..ff78b5d41bbfade26725322913978969e9465774 --- /dev/null +++ b/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/323ff8ab-5b3c-4603-a4d5-667546c604d5_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:a1f3d94176749f3c75d053a719d4582be06c21c3e3235822c880a8bfc7415f93 +size 3373210 diff --git a/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/full.md b/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/full.md new file mode 100644 index 0000000000000000000000000000000000000000..218c8c9e8478fc5c872628cb738c090b1e0bc0c7 --- /dev/null +++ b/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/full.md @@ -0,0 +1,351 @@ +# MIMO-NeRF: Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields + +Takuhiro Kaneko +NTT Communication Science Laboratories, NTT Corporation + +# Abstract + +Neural radiance fields (NeRFs) have shown impressive results for novel view synthesis. However, they depend on the repetitive use of a single-input single-output multilayer perceptron (SISO MLP) that maps 3D coordinates and view direction to the color and volume density in a sample-wise manner, which slows the rendering. We propose a multi-input multi-output NeRF (MIMO-NeRF) that reduces the number of MLPs running by replacing the SISO MLP with a MIMO MLP and conducting mappings in a group-wise manner. One notable challenge with this approach is that the color and volume density of each point can differ according to a choice of input coordinates in a group, which can lead to some notable ambiguity. We also propose a self-supervised learning method that regularizes the MIMO MLP with multiple fast reformulated MLPs to alleviate this ambiguity without using pretrained models. The results of a comprehensive experimental evaluation including comparative and ablation studies are presented to show that MIMO-NeRF obtains a good trade-off between speed and quality with a reasonable training time. We then demonstrate that MIMO-NeRF is compatible with and complementary to previous advancements in NeRFs by applying it to two representative fast NeRFs, i.e., a NeRF with a sampling network (DONeRF) and a NeRF with alternative representations (TensoRF). + +# 1. Introduction + +Images are two-dimensional (2D) projections of three-dimensional (3D) scenes. Solving the inverse problem, that is, learning 3D representations from 2D images and synthesizing novel views, is a fundamental concern in computer vision and graphics and has been extensively studied for various applications such as photo editing, content creation, virtual reality, and environmental understanding. + +With the advent of implicit neural representations + +![](images/da7cd6167e4c90517e2d9806f52c9dd8930bae0734d742314d72b4bb0c0f1f1b.jpg) +(a) NeRF + +![](images/0172601d03809291881bba5f36c935b4b3388c06f4ac60bfa296da32699e1cac.jpg) +(b) MIMO-NeRF (proposed) +Figure 1. Comparison between NeRF and MIMO-NeRF (proposed). (a) A typical NeRF uses a SISO MLP that maps 3D coordinates and view direction to the color and volume density in a sample-wise manner. (b) In contrast, the proposed MIMO-NeRF uses a MIMO MLP that performs mappings in a group-wise manner. This change reduces the number of MLPs running and improves the rendering speed, but also requires addressing ambiguity in the color and volume density caused by the fact that these values are determined in a non-unique manner by a set of input coordinates that vary by viewpoint, grouping, and sampling. The main technical contribution of the present work is that of providing methods to mitigate this challenge. We demonstrate the impact of the proposed technique in Figure 2. + +(e.g., [56, 44, 39, 28, 69, 71, 55]), substantial advancements have been made towards addressing this problem. Neural radiance fields (NeRFs) [39] have been noted as a successful approach. A NeRF represents a scene using a continuous function that maps 3D coordinates and view direction to the color and volume density and renders a pixel by integrating the outputs on a ray using volume rendering [34]. This formulation enables NeRF to learn to synthesize geometrically consistent and high-fidelity novel views with only 2D supervision. + +Despite this advantage, a typical NeRF suffers from slow rendering because it uses a single-input single-output (SISO) MLP that calculates the RGB color and volume density in a sample-wise manner (Figure 1(a)). Although this architecture ensures the independent representation of each point, which is useful, for example, for learning view-independent volume density, its computational cost increases in proportion to the number of samples for each + +ray (e.g., on the order of hundreds). Several methods developed to address this issue can be roughly categorized into two approaches, including (1) sample reduction and (2) alternative representations. + +A typical sample reduction strategy reduces the number of samples on a ray using a sampling network based on the depth [41] or density of a pretrained NeRF [47] or using a sampling network with an adaptive optimization mechanism [29, 14, 27]. These methods successfully accelerate the rendering process while retaining the quality of an image adequately. However, most of these techniques still use a SISO MLP to predict the colors and volume densities of selected samples; therefore, they still need to run MLPs many times in proportion to the number of selected samples. This issue can be alleviated by reducing the number of selected samples, although this deteriorates the quality of the synthesized images accordingly. + +As alternative representations, various sophisticated and faster representations such as 3D voxel grids [17, 22, 30, 66, 60], sparse voxel-based octrees [70, 15], multiplane images [65], tri-planes [7], vector-matrix decomposition [9], hashes [40], NeRF-specific structures [24], and space-wise MLPs [50, 51] have been devised. These representations contribute to achieving fast rendering while retaining image quality moderately well. However, after powerful features are extracted using alternative representations, SISO MLPs are still commonly used for the final prediction of color or volume density owing to their memory-efficient and continuous nature. Hence, part of the calculation cost still increases depending on the number of samples. + +Consequently, owing to its compact, continuous (i.e., resolution-free), and independent (e.g., view-independent) nature, a SISO MLP is commonly used in various NeRFs. However, as mentioned above, the calculation cost increases with the number of samples. This is not preferable when considering the improvement in rendering speed. Possible simple solutions include, for example, a reduction of the number of samples or a reduction of the size of a model with a corresponding sacrifice of image quality. However, these solutions are not necessarily the best for handling the tradeoff between quality and speed. Alternatively, we propose a multi-input multi-output NeRF (MIMO-NeRF), which is a novel variant of NeRF that represents a scene using a MIMO MLP that conducts mappings in a group-wise manner (Figure 1(b)). This modification enables a reduction in the number of MLPs running according to the number of grouped samples and consequently improves rendering speed. + +However, in this approach, the uniqueness of the color and volume density of each point is not ensured because they are determined not only by the coordinates of the corresponding point but also by the coordinates of the other points in a group, which vary by viewpoint, grouping, and + +![](images/f456a4e5b7fbb311e92d30b9fe46fcd072e7686ff936ab9c219de744be5a1438.jpg) +Figure 2. Challenge of training MIMO-NeRF and the impact of the proposed self-supervised learning. (a) MIMO-NeRF-naive suffers from ambiguity in the color and volume density of each point and deteriorates image quality. (b) We propose self-supervised learning to address this problem without relying on a pretrained model. This technique improves image quality. + +sampling. This leads to some ambiguity and causes fluctuation artifacts as shown in Figure 2(a). In particular, this ambiguity can be problematic when learning a 3D representation using only 2D supervision because obtaining direct supervision that can resolve the ambiguity is difficult. One possible solution is to train a standard (i.e., SISO) NeRF first and then distill the model onto the corresponding MIMO-NeRF. However, this increases training time because both student and teacher NeRFs must be trained. Alternatively, we have also developed a novel self-supervised learning approach in which we reformulate a MIMO MLP in several ways (in particular, we use group shift (Figure 3) and variation reduction (Figure 4)) and impose a consistent regularization so that the reformulated MIMO MLPs produce the same outputs. Because each reformulated MIMO MLP can render a pixel faster than the original SISO MLP, we can prevent a large sacrifice of training time even when using multiple reformulated MIMO MLPs by adequately adjusting the reformulation configuration. Figure 2(b) shows an example of the effects of this learning scheme. + +We investigated the benchmark performance of MIMO-NeRF by comparing it with possible alternatives (including the distillation of a pretrained NeRF, sample reduction, and reduction of the model size). We also performed ablation studies to examine the validity of each component of the proposed self-supervised learning method. We apply MiMO-NeRF to two representative fast NeRFs, including a NeRF with a sampling network (DONeRF [41]) and a model with alternative representations (TensoRF [9]) to demonstrate that it is compatible with and complementary to previous advancements in NeRFs. + +The main contributions of this study are summarized as follows. + +- To speed up the rendering of NeRF, we propose MIMO-NeRF, which represents a scene using a MIMO + +MLP that maps the coordinates on a ray to the colors and volume densities in a group-wise manner. + +- We introduce novel self-supervised learning to mitigate the ambiguity in the color and volume density of each point and enable MIMO-NeRF to be trained without relying on pretrained models. +- We examined the effectiveness of MIMO-NeRF through a comprehensive experimental evaluation, and the results demonstrate the versatility of MIMO-NeRF in applications to two representative fast NeRFs. We also provide more detailed analyses and extended results in the Supplementary Material. + +# 2. Related work + +Implicit neural representations. Implicit neural representations have attracted attention in 3D shape [45, 35, 11, 36, 52, 18, 3, 20] and 3D scene [25, 46, 6, 12, 54] reconstructions owing to their memory-efficient, continuous (i.e., resolution-free), and 3D-aware characteristics. Although research began with explicit 3D supervision, learning implicit 3D only from 2D supervision (i.e., inverse graphics) has also been achieved by incorporating differentiable rendering [56, 31, 44, 32, 39, 28, 69, 71, 55]. In this study, we focus on NeRFs as a representative example of the latter owing to their remarkable success in synthesizing geometrically consistent and high-quality novel view. However, applying our ideas to other implicit neural representations, such as those mentioned above, remains as an interesting direction for future research. + +Advancements in NeRFs. Various extensions have been proposed since the emergence of NeRF. For example, representative research topics include (1) improving image quality and enhancing applicable scenes (e.g., [72, 33, 49, 16, 67, 4, 5, 37, 62, 10]), (2) incorporation into other models, e.g., deep generative models, such as generative adversarial networks (GANs) [19] and diffusion probabilistic models [58, 23] (e.g., [53, 8, 43, 42, 21, 7, 13, 68, 26, 57, 48]), and (3) accelerating NeRFs for fast inference or fast training (e.g., [41, 47, 29, 14, 27, 17, 22, 30, 66, 60, 70, 15, 65, 7, 9, 40, 24, 50, 51]). The present work falls into the third category. However, our proposed approach is complementary to previous studies, including most of the abovementioned works in all categories, because SISO MLPs have commonly been used as a partial or main network in previous studies and improving their rendering speed by replacing SISO MLPs with the proposed MIMO MLP is feasible. The results of the experimental evaluation validated this potential (Sections 5.4 and 5.5). + +Acceleration of NeRFs. As discussed in Section 1, a typical NeRF is well known for its slow rendering because it use a SISO MLP. Several approaches have been developed to address this issue. These can be roughly categorized + +into two approaches, including (1) sample reduction and (2) alternative representations. (1) As described in Section 1, methods that reduce the number of samples using a sampling network can improve rendering speed by replacing a SISO MLP with the proposed MIMO MLP. We validated this statement during an experiment (Section 5.4) by applying our ideas to a representative NeRF in this category (DONeRF [41]). Another common approach in the first category is to render pixels using a light-field network [55, 2, 59, 63] instead of volume rendering [34]. This approach has been shown to achieve fast rendering by running only a single MLP for a given ray. However, owing to the lack of explicit geometry-aware representations driven by the use of volume densities, these methods suffer from limitations that are not faced by a standard NeRF in terms of restrictions on applicable scenes (e.g., toy datasets [55] and forward-facing datasets [2]), a requirement for high-capacity models (e.g., a deeper MLP [63] and a transformer [59]), and the need for extra modules (e.g., metalearned priors [55], pretrained NeRFs [2, 63], or additional encoders [59]). (2) As explained in Section 1, alternative representations have the potential to accelerate the rendering speed by replacing the SISO MLP with the proposed MIMO MLP. We present an empirical investigation of this potential in Section 5.5 by incorporating MIMO-NeRF into TensoRF [9], a representative model in this category. + +Learning of fast NeRFs. Knowledge distillation (or baking) methods are commonly used to train fast NeRFs. In these methods, a standard NeRF is first trained and then baked to faster representations [17, 22, 24, 50, 51]. However, this approach is disadvantageous in terms of training time because two separate models must be trained, i.e., teacher and student NeRFs. As an alternative, we consider a self-supervised learning approach in which we can train a model without a large increase in training time. We examine the performance differences between the proposed self-supervised learning scheme and a knowledge distillation scheme in Section 5.1. + +# 3. Preliminaries: NeRF + +We begin by explaining NeRFs as the basis for our model. As shown in Figure 1(a), a NeRF represents a point in a 3D space using a continuous SISO function $f_{\mathrm{SISO}}$ that maps the 3D position $\mathbf{x} \in \mathbb{R}^3$ and view direction $\mathbf{d} \in \mathbb{S}^2$ to the RGB color $\mathbf{c}(\mathbf{x}, \mathbf{d}) \in \mathbb{R}^3$ and volume density $\sigma(\mathbf{x}) \in \mathbb{R}^+$ in a sample-wise manner. + +$$ +f _ {\mathrm {S I S O}}: \mathbb {R} ^ {3} \times \mathbb {S} ^ {2} \rightarrow \mathbb {R} ^ {3} \times \mathbb {R} ^ {+}, (\mathbf {x}, \mathbf {d}) \mapsto (\mathbf {c}, \sigma). \tag {1} +$$ + +Specifically, positional encoding [39, 61] is applied to $\mathbf{x}$ and $\mathbf{d}$ to represent the high-frequency details of an image. Subsequently, an MLP is applied to the encoded inputs to obtain $\mathbf{c}$ and $\sigma$ . For simplicity, we represent these series of processes in a unified manner as $f_{\mathrm{SISO}}$ . + +A NeRF is based on ray tracing, in which a camera ray is defined as $\mathbf{r}(t) = \mathbf{o} + t\mathbf{d}$ , where $\mathbf{o}$ and $\mathbf{d}$ respectively denote the origin and direction of the camera and $t$ denotes a distance from the origin. A NeRF calculates the color of each pixel $\hat{\mathbf{C}}(\mathbf{r})$ by integrating the colors and volume densities on a ray $\mathbf{r}(t)$ within $t \in [t_n, t_f]$ using volume rendering [34]. In implementation, the calculation of the integral is intractable; therefore, a ray is discretized into $N$ points; alternatively, the following discretized formulation can be used. + +$$ +\hat {\mathbf {C}} (\mathbf {r}) = \sum_ {i = 1} ^ {N} T _ {i} \alpha_ {i} \mathbf {c} _ {i}, \text {w h e r e} T _ {i} = \prod_ {j = 1} ^ {i - 1} (1 - \alpha_ {j}), \tag {2} +$$ + +where the subscript $i$ indicates that the variable corresponds to the $i$ -th point on a ray, $\alpha_{i} = 1 - \exp (-\sigma_{i}\delta_{i})$ is an alpha value, and $\delta_{i} = t_{i + 1} - t_{i}$ is the distance between the $i$ -th and $(i + 1)$ -th points. $f_{\mathrm{SISO}}$ is optimized by minimizing the following pixel-wise loss. + +$$ +\mathcal {L} _ {\mathrm {p i x e l}} = \| \hat {\mathbf {C}} (\mathbf {r}) - \mathbf {C} (\mathbf {r}) \| _ {2} ^ {2}, \tag {3} +$$ + +where $\mathbf{C}(\mathbf{r})$ is the ground-truth color for a ray $\mathbf{r}$ . In practice, this loss is calculated for $\mathbf{r} \in \mathcal{R}$ , where $\mathcal{R}$ denotes a set of rays in each batch. + +In practice, a NeRF uses coarse and fine networks. In the coarse network, a ray is discretized into $N_{c}$ points using stratified sampling, whereas in the fine network, a ray is discretized into $N_{c} + N_{f}$ points using hierarchical sampling in which $N_{f}$ additional points are sampled according to the output of the coarse network. The two networks are optimized by minimizing $\mathcal{L}_{\mathrm{pixel}}$ for $\hat{\mathbf{C}}(\mathbf{r})$ predicted by each network. Hereafter, we omit a variable in parentheses (e.g., $(\mathbf{r})$ ) for simplicity. + +# 4. MIMO-NeRF + +# 4.1. MIMO formulation + +There are several ways to group the input samples when constructing a MIMO MLP. For example, we can construct a general MLP that can accept any combination of samples in a 3D space, or we can construct a specific MLP that only accepts a group of nearby samples. In preliminary experiments (Appendix A.1), we found that the latter significantly outperformed the former because general models are more difficult to train than more specific models. Therefore, we adopted the latter in this study. In particular, we group neighboring samples on a ray as shown in Figure 1(b).3 + +More formally, given $N$ samples on a ray, we group $N_{p}$ samples from the sample nearest to the camera and create + +$N / N_{p}$ groups. Subsequently, we apply a MIMO function $f_{\mathrm{MIMO}}$ to each group as follows. + +$$ +\begin{array}{l} f _ {\mathrm {M I M O}}: (\mathbb {R} ^ {3}) ^ {N _ {p}} \times \mathbb {S} ^ {2} \rightarrow (\mathbb {R} ^ {3} \times \mathbb {R} ^ {+}) ^ {N _ {p}}, \\ \left(\mathbf {x} _ {i}, \dots , \mathbf {x} _ {j}, \mathbf {d}\right) \mapsto \left(\mathbf {c} _ {i}, \dots , \mathbf {c} _ {j}, \sigma_ {i}, \dots , \sigma_ {j}\right), \tag {4} \\ \end{array} +$$ + +where $i \in \{1, 1 + N_p, \dots, 1 + N - N_p\}$ and $j = i + N_p - 1$ . Assuming that the grouped samples are lined on a ray, we use a single direction $\mathbf{d}$ in the input of $f_{\mathrm{MIMO}}$ . In this formulation, the number of MLPs running to render a pixel (#Run) is equal to the number of groups and is calculated as #Run = $N / N_p$ . Therefore, we can reduce the calculation cost, particularly that of #Run, by increasing $N_p$ . + +In inference, the only necessary modification to a NeRF is the simple replacement of $f_{\mathrm{SISO}}$ with $f_{\mathrm{MIMO}}$ and the same volume rendering (Equation 2) and sampling scheme (i.e., stratified and hierarchical sampling) can be used. With this modification strategy, MIMO-NeRF exhibits high compatibility and complementarity with previous NeRFs. + +During training, $\mathcal{L}_{\mathrm{pixel}}$ (Equation 3) can be used for $\hat{\mathbf{C}}$ obtained using $f_{\mathrm{MIMO}}$ . However, this loss does not necessarily suffice to address the ambiguity in the color and volume density of each point because this ambiguity occurs in a 3D space and the loss cannot regularize the 3D representations explicitly. Hence, we introduce self-supervised learning as discussed in subsequent sections. + +# 4.2. MIMO reformulation + +One possible solution to this ambiguity is to train a standard (i.e., SISO) NeRF first and then distill the model onto a corresponding MIMO-NeRF. However, this solution involves an increase in training time because it requires training not only a MIMO-NeRF but also a SISO NeRF. Consequently, this solution cannot entirely take advantage of the fast rendering of MIMO-NeRF in training. + +Alternatively, we reformulate a MIMO MLP in multiple ways and impose a consistent regularization to produce the same RGB colors and alpha values. Because each reformulated MIMO MLP can render a pixel faster than the original SISO MLP, we can prevent a large increase in training time even when using multiple reformulated MIMO MLPs by adequately adjusting the reformulation configuration. When implementing this idea, the question arises as to how best to reformulate a MIMO MLP. To this end, we developed two methods, including (1) group shift and (2) variation reduction. + +Group shift. We consider restricting this ambiguity by assessing each point in multiple ways using different groups and imposing consistency on the assessed results. More formally, we implement this by shifting groups and rewriting Equation 4 as follows. + +$$ +\begin{array}{l} f _ {\mathrm {M I M O}} ^ {\mathrm {s h i f t}}: (\mathbb {R} ^ {3}) ^ {N _ {p}} \times \mathbb {S} ^ {2} \to (\mathbb {R} ^ {3} \times \mathbb {R} ^ {+}) ^ {N _ {p}}, \\ \left(\mathbf {x} _ {i ^ {\prime}}, \dots , \mathbf {x} _ {j ^ {\prime}}, \mathbf {d}\right) \mapsto \left(\mathbf {c} _ {i ^ {\prime}}, \dots , \mathbf {c} _ {j ^ {\prime}}, \sigma_ {i ^ {\prime}}, \dots , \sigma_ {j ^ {\prime}}\right), \tag {5} \\ \end{array} +$$ + +![](images/379aed44382020f4991b234dce1376b248d3a1ead134d95e989fb0597105b79b.jpg) +Figure 3. Example of the group shift when $N_{p} = 4$ and $s = 2$ . We shift each group by $s$ toward the camera after padding $s$ samples before the front sample. This procedure enables assessing each sample in multiple ways using different groups. + +where $i' \in \{k, k + N_p, \ldots, k + N\}$ and $j' = i' + N_p - 1$ . Here, $k$ is the head index of the first group, which is shifted by $s \in \{1, \ldots, N_p - 1\}$ toward the camera. Hence, $k \in \{2 - N_p, \ldots, 0\}$ . In practice, it is randomly sampled during training. More strictly, we add padding before this process to represent a sample with an index exceeding the original index, i.e., $i' < 1$ or $j' > N$ . For clarity, we present an example in which $N_p = 4$ and $s = 2$ in Figure 3. + +Variation reduction. In the original MIMO formulation, the abovementioned ambiguity is caused by $N_{p}$ different input samples. To mitigate this, we consider reducing the variation in the input by replacing Equation 4 with the following. + +$$ +f _ {\mathrm {M I M O}} ^ {\text {r e d u c e}}: (\mathbb {R} ^ {3}) ^ {N _ {p}} \times \mathbb {S} ^ {2} \to (\mathbb {R} ^ {3} \times \mathbb {R} ^ {+}) ^ {N _ {p}}, +$$ + +$$ +\begin{array}{l} \left(\left[ \mathbf {x} _ {i ^ {\prime \prime}} \right] ^ {R}, \ldots , \left[ \mathbf {x} _ {j ^ {\prime \prime}} \right] ^ {R}, \mathbf {d}\right) \mapsto \left(\mathbf {c} _ {i _ {1} ^ {\prime \prime}}, \ldots , \mathbf {c} _ {i _ {R} ^ {\prime \prime}}, \ldots , \mathbf {c} _ {j _ {1} ^ {\prime \prime}}, \ldots , \mathbf {c} _ {j _ {R} ^ {\prime \prime}}, \right. \\ \sigma_ {i _ {1} ^ {\prime \prime}}, \dots , \sigma_ {i _ {R} ^ {\prime \prime}}, \dots , \sigma_ {j _ {1} ^ {\prime \prime}}, \dots , \sigma_ {j _ {R} ^ {\prime \prime}}), \tag {6} \\ \end{array} +$$ + +where $[\cdot ]^R$ denotes the operation of repeating the given variable $R$ times, $i''\in \{1,1 + \frac{N_p}{R},\ldots ,1 + N - \frac{N_p}{R}\}$ , and $j^{\prime \prime} = i^{\prime \prime} + \frac{N_p}{R} -1$ . After applying $f_{\mathrm{MIMO}}^{\mathrm{reduce}}$ , we average $(\mathbf{c}_{k_1^{\prime \prime}},\dots,\mathbf{c}_{k_R^{\prime \prime}})$ and $(\sigma_{k_1^{\prime \prime}},\dots,\sigma_{k_R^{\prime \prime}})$ to obtain $\mathbf{c}_{k^{\prime \prime}}$ and $\sigma_{k^{\prime \prime}}$ , where $k^{\prime \prime}\in \{i^{\prime \prime},\dots,j^{\prime \prime}\}$ . In this formulation, the mentioned ambiguity is reduced by decreasing input variation from $N_{p}$ to $\frac{N_p}{R}$ . Conversely, the number of MLPs running increases by factor of $R$ , i.e., $\# \operatorname {Run} = N / N_p\times R$ ; therefore, we need to select $R$ carefully in practice to avoid a large increase in training time. For clarity, we present an example case in which $N_{p} = 4$ and $R = 2$ in Figure 4. + +# 4.3. MIMO objective + +Through the above processes, we obtain $M$ reformulated MIMO MLPs in which we use different $s$ for each MIMO MLP and set $R$ such that the total number of # Run is not larger than that of the original SISO MLP. Hereafter, we use the superscript $m \in \{1, \dots, M\}$ to denote the variable corresponding to the $m$ -th reformulated MIMO MLP, e.g., $\hat{\mathbf{C}}^m$ and $R^m$ . We train these MLPs using two loss functions, including pixel-wise and 3D consistency losses. + +![](images/c887b051e676ac30bc781ef5cfb2f4ef8250c929a58630e1cd808f8722c54e7c.jpg) +Figure 4. Example of variation reduction when $N_{p} = 4$ and $R = 2$ . Samples with the same color correspond to the same coordinate. In $f_{\mathrm{MIMO}}^{\mathrm{reduce}}$ , we reduce the number of unique samples in a group from $N_{p} (= 4)$ to $\frac{N_{p}}{R} (= 2)$ by repeating each sample $R (= 2)$ times to reduce the variation in a group. + +Pixel-wise loss. We apply the pixel-wise loss (Equation 3) to each $\hat{\mathbf{C}}^m$ as follows. + +$$ +\mathcal {L} _ {\text {p i x e l}} ^ {\mathrm {M I M O}} = \sum_ {m = 1} ^ {M} \| \hat {\mathbf {C}} ^ {m} - \mathbf {C} \| _ {2} ^ {2}. \tag {7} +$$ + +3D consistency loss. The pixel-wise loss provides supervision in a 2D space; however, it cannot impose an explicit regularization in a 3D space. Hence, we introduce a 3D consistency loss that encourages the reformulated MIMO MLPs to produce the same colors and alpha values in the 3D space. The 3D consistency loss consists of a color 3D consistency loss $\mathcal{L}_{\mathrm{3D}}^{\mathrm{color}}$ and an alpha value 3D consistency loss $\mathcal{L}_{\mathrm{3D}}^{\mathrm{alpha}}$ as follows. + +$$ +\begin{array}{l} \mathcal {L} _ {\mathrm {3 D}} ^ {\mathrm {c o l o r}} = \sum_ {m _ {1} = 1} ^ {M - 1} \sum_ {m _ {2} = m _ {1} + 1} ^ {M} \frac {1}{N} \sum_ {i = 1} ^ {N} \left[ \mu_ {m _ {1}} ^ {m _ {2}} \| \mathbf {c} _ {i} ^ {m _ {1}} - \operatorname {s g} \left(\mathbf {c} _ {i} ^ {m _ {2}}\right) \| _ {2} ^ {2} \right. \\ + \mu_ {m _ {2}} ^ {m _ {1}} \| \operatorname {s g} \left(\mathbf {c} _ {i} ^ {m _ {1}}\right) - \mathbf {c} _ {i} ^ {m _ {2}} \| _ {2} ^ {2} ], \tag {8} \\ \end{array} +$$ + +$$ +\begin{array}{l} \mathcal {L} _ {\mathrm {3 D}} ^ {\mathrm {a l p h a}} = \sum_ {m _ {1} = 1} ^ {M - 1} \sum_ {m _ {2} = m _ {1} + 1} ^ {M} \frac {1}{N} \sum_ {i = 1} ^ {N} \left[ \mu_ {m _ {1}} ^ {m _ {2}} \| \alpha_ {i} ^ {m _ {1}} - \operatorname {s g} \left(\alpha_ {i} ^ {m _ {2}}\right) \| _ {2} ^ {2} \right. \\ + \mu_ {m _ {2}} ^ {m _ {1}} \| \operatorname {s g} \left(\alpha_ {i} ^ {m _ {1}}\right) - \alpha_ {i} ^ {m _ {2}} \| _ {2} ^ {2} ]. \tag {9} \\ \end{array} +$$ + +where "sg" indicate a stop-gradient operation. The 3D consistency loss $\mathcal{L}_{\mathrm{3D}}$ is calculated by $\mathcal{L}_{\mathrm{3D}} = \mathcal{L}_{\mathrm{3D}}^{\mathrm{color}} + \mathcal{L}_{\mathrm{3D}}^{\mathrm{alpha}}$ . We define $\mu_{m_i}^{m_j}$ as $\mu_{m_i}^{m_j} = \frac{\sqrt{R^{m_j}}}{\sqrt{R^{\max} \sqrt{R^{m_i}}}}$ , where $R^{\max}$ is the maximum of $R^{m}$ in $m \in \{1, \ldots, M\}$ . We use this asymmetric weight on the assumption that $\mathbf{c}_i^m$ and $\alpha_i^m$ with greater $R^{m}$ have lower ambiguity and are more reliable. Hence, the effect of $\mathcal{L}_{\mathrm{3D}}$ is reduced. We empirically investigated the importance of this effect through an ablation study as described in Section 5.3. + +Full objective. The full objective is defined as follows. + +$$ +\mathcal {L} _ {\mathrm {M I M O}} = \mathcal {L} _ {\text {p i x e l}} ^ {\mathrm {M I M O}} + \lambda \mathcal {L} _ {\mathrm {3 D}}, \tag {10} +$$ + +where $\lambda$ is a hyperparameter that balances the pixel-wise loss and 3D consistency loss. + +# 5. Experiments + +We conducted five experiments to investigate the effectiveness of MIMO-NeRF. In the first three experiments, we conducted a comprehensive study, including an investigation of benchmark performance (Section 5.1), an investigation of the trade-off between speed and quality (Section 5.2), and ablation studies (Section 5.3). In the remaining two experiments, we examined the versatility of MIMO-NeRF by applying it to two representative fast NeRFs, including a NeRF with a sampling network, i.e., DONeRF [41] (Section 5.4), and a NeRF with alternative representations, i.e., TensoRF [9] (Section 5.5). The main results of these experiments are provided here, and detailed analyses are presented with extended results in Appendix A. The implementation details are presented in Appendix B. + +# 5.1. Investigation of benchmark performance + +First, we investigated the benchmark performance of MIMO-NeRF by applying our ideas to the original NeRF [39]. In particular, we examined three variants of MIMO-NeRF, including MIMO-NeRF-naive, which simply replaced $f_{\mathrm{SISO}}$ (Equation 1) with $f_{\mathrm{MIMO}}$ (Equation 4) and was trained with a standard pixel-wise loss (Equation 3). MIMO-NeRF-distill, which is a student model distilled from a pretrained standard (i.e., SISO) NeRF. During training, we used a 3D consistency loss (Equations 8 and 9) that was adjusted for knowledge distillation, in addition to the pixelwise loss. MIMO-NeRF-self, which is MIMO-NeRF that adopted the proposed self-supervised learning. We examined the performance when $N_p$ was varied within $\{2,4,8\}$ . + +Datasets. We investigated the benchmark performance on two commonly-used datasets. (1) Blender dataset [39] includes eight scenes, each of which consists of $360^{\circ}$ views of complex objects at a resolution of $800 \times 800$ pixels. We used 100 and 200 views for training and testing, respectively. (2) Local Light Field Fusion (LLFF) dataset [38, 39], which consists of eight complex real-world scenes, each of which includes 20-62 forward-facing views at $1008 \times 756$ pixels. One-eighth of the images were used for testing, and the remainder were used for training. Where not otherwise specified, we used half-sized images following the default settings of a widely-used source code for $\mathrm{NeRF}^5$ to better investigate the various configurations. + +Implementation. For a fair comparison, we implemented all the models with a commonly-used source code for $\mathrm{NeRF}^5$ and trained the models using the default settings provided in the code. The number of samples was set as $N_{c} = 64$ and $N_{f} = 128$ for the Blender dataset and + +$N_{c} = 64$ and $N_{f} = 64$ for the LLFF dataset. For MIMO-NeRF-self, we used two formulations with $R^{1} = R^{2} = 1$ when $N_{p} = 2$ , two formulations with $R^{1} = 1$ and $R^{2} = 2$ when $N_{p} = 4$ , and three formulations with $R^{1} = 1$ , $R^{2} = 2$ , and $R^{3} = 4$ when $N_{p} = 8$ . MIMO-NeRF-self was trained individually depending on $N_{p}$ . An investigation of different reformulation methods is presented in Appendix A.2. Group shifts were applied to all cases. We set $\lambda$ to 1 and 0.4 for the Blender and LLFF datasets, respectively. The effect of $\lambda$ is analyzed in Appendix A.3. The implementation details are presented in Appendix B.1. + +Evaluation metrics. Following the original NeRF study [39], we used the peak signal-to-noise ratio (PSNR), structural similarity index (SSIM) [64], and learned perceptual image patch similarity (LPIPS) [73] to quantitatively evaluate the image quality. To assess the calculation cost of inference and training, we report inference time (I-time) measured with an NVIDIA GeForce RTX 3080 Ti GPU and training time (T-time) measured with an NVIDIA A100-SXM4-80GB GPU. We also provide # Run $\left(= \frac{N_c + (N_c + N_f)}{N_p}\right)$ and the number of parameters (# Params) as supplementary information. # Params increases in MIMO-NeRF mainly because the total dimension of the positional embeddings is increased by $N_{p}$ times according to the increase in the inputs. + +# Results. From Table 1, the following is observed. + +Image quality. MIMO-NeRF-self outperformed not only MIMO-NeRF-naive but also MIMO-NeRF-distill in most cases in terms of PSNR, SSIM, and LPIPS. We conjecture that this occurred because the joint optimization of the teacher and student networks in MIMO-NeRF-self was more effective for training than the student-only optimization in MIMO-NeRF-distill. Even MIMO-NeRF-self suffered from a trade-off between speed and quality with increasing $N_{p}$ ; however, MIMO-NeRF-self performed better than or comparably to the original NeRF when $N_{p} = 2$ . This may have occurred because the advantage of accumulating neighboring information and the disadvantage of handling the ambiguity were antagonistic in this case. + +Inference speed. All MIMO-NeRFs with the same inference procedure showed inference times improved by a factor of 1.84–5.78 with increasing $N_{p}$ . + +Training speed. MIMO-NeRF-naive achieved the fastest training because it used only a single MIMO formulation during training. MIMO-NeRF-self required more training time because it uses multiple MIMO reformulations; however, each calculation cost is low. Therefore, it did not suffer from a large increase in training time compared + +
ModelNpPSNR↑SSIM↑LPIPS↓Blender # Run↓I-time↓ (s)T-time↓ (h)# Params (M)PSNR↑SSIM↑LPIPS↓LLFF # Run↓I-time↓ (s)T-time↓ (h)# Params (M)
NeRF131.040.9510.0552569.604.701.1927.720.8710.1501928.383.391.19
MIMO-NeRF-naive30.180.9440.0651285.153.091.2627.310.8600.167964.552.121.26
MIMO-NeRF-distill 2230.760.9490.0581285.159.461.2627.500.8630.169964.556.811.26
MIMO-NeRF-self331.260.9530.0541285.155.361.2627.700.8700.155964.553.971.26
MIMO-NeRF-naive28.620.9270.091642.792.021.3926.290.8240.218482.461.571.39
MIMO-NeRF-distill 4430.220.9460.065642.798.421.3927.370.8610.172482.466.251.39
MIMO-NeRF-self330.940.9500.058642.794.681.3927.510.8650.162482.463.441.39
MIMO-NeRF-naive26.340.8950.133321.661.661.6525.100.7740.284241.451.241.65
MIMO-NeRF-distill 8829.390.9370.075321.668.071.6527.010.8510.184241.455.911.65
MIMO-NeRF-self330.400.9450.065321.665.861.6526.970.8510.180241.454.431.65
+ +Table 1. Benchmark performance of MIMO-NeRFs. MIMO-NeRF-self outperformed MIMO-NeRF-naive and MIMO-NeRF-distill in terms of PSNR, SSIM, and LPIPS in most cases with shorter training time than MIMO-NeRF-distill. All MIMO-NeRFs outperformed the original NeRF in terms of inference time owing to the reduction of # Run. + +![](images/21677546a92471a00f99cbfe2616dfc1981e5c46a2b0b6e3d65410077252142c.jpg) +Figure 5. Qualitative comparison between NeRF and MIMO-NeRFs with $N_{p} = 8$ . The models were trained using full-sized images. MIMO-NeRF-naive (c) produced some artifacts owing to the ambiguity in the color and volume density of each point. MIMO-NeRF-self (d) was useful for addressing this issue, and its results were close to those of NeRF (b), while inference time were improved by a factor of 5.8. + +with MIMO-NeRF-distill, which requires training not only a MIMO-NeRF but also a SISO NeRF. + +Summary. From these results, we found that when $N_{p} = 2$ , MIMO-NeRF-self improved the inference speed of NeRF without compromising image quality, and when $N_{p}$ was larger, there was a trade-off between speed and quality. We examine the validity of this trade-off in Section 5.2. + +Qualitative results. Figure 5 shows a qualitative comparison between NeRF, MIMO-NeRF-naive, and MIMO-NeRF-self. In this experiment, we used full-sized images to train the models and set $N_{p}$ to 8 for MIMO-NeRFs. MIMO-NeRF-naive produced some artifacts, whereas MIMO-NeRF-self adequately addressed this issue. The additional results are provided in Appendix A.6. + +![](images/343e964da66cab51a41ba04f942d480e4286c6b42985dec995480b1c98310310.jpg) +Figure 6. Relationship between FLOPs and PSNR. Higher values indicate better the image quality. Faster speeds are shown to the left. MIMO-NeRF-self achieves the best trade-off between speed and quality. + +![](images/707968fd4b819dc01b68f13bf8c8572ee630f047ae633a78e3147bb88d7c07b8.jpg) + +# 5.2. Investigation of speed-quality trade-off + +We compared MIMO-NeRF with possible alternatives to investigate whether it achieved a good trade-off between speed and quality. In particular, we focused on methods that are general and applicable to various NeRFs, similar to MIMO-NeRF, and examined two variants, including NeRF-few, which reduced the number of samples on a ray, and NeRF-small, which reduced the number of features in the hidden layers. We adjusted the parameters such that their FLOPs were comparable to those of MIMO-NeRF.7 + +Results. The relationship between the FLOPs and PSNR is plotted in Figure 6. We found that MIMO-NeRF-self obtained a better trade-off between speed and quality than NeRF-few and NeRF-small. We provide other relationships (e.g., relationships between FLOPs/inference time and PSNR/SSIM/LPIPS) in Appendix A.4. $^{8}$ + +
\(N_p\)GSCLAWBlenderLLFF
PSNR↑SSIM↑LPIPS↓PSNR↑SSIM↑LPIPS↓
2✓30.170.9430.06727.210.8560.170
✓30.540.9450.06527.480.8650.161
✓✓31.260.9530.05427.700.8700.155
4✓✓30.840.9490.05827.390.8620.166
✓29.480.9360.07726.460.8320.206
✓✓30.870.9490.06027.440.8640.164
✓✓✓30.940.9500.05827.510.8650.162
8✓✓29.810.9410.06926.970.8510.179
✓27.390.9070.11624.290.7340.332
✓✓30.160.9420.07126.690.8430.192
✓✓✓30.400.9450.06526.970.8510.180
+ +# 5.3. Ablation studies + +We also conducted ablation studies to better understand the performance of each element of the proposed self-supervised learning method. Specifically, we investigated the importance of group shift, 3D consistency loss, and asymmetric weights. When asymmetric weights were ablated, $\mu_{m_i}^{m_j}$ was set to 1. + +Results. The results are listed in Table 2. We found that the full model achieved the best performance in most cases. The results validate the importance of each technique. + +# 5.4. Application to DONeRF + +We incorporated MIMO-NeRF into DONeRF [41], a representative NeRF with a sampling network, to demonstrate that MIMO-NeRF can complement existing fast NeRFs. DONeRF uses a sampling network called a depth oracle network to select samples and calculates the colors and volume densities of the selected samples using a shading network. It handles the trade-off between speed and image quality by adjusting the number of selected samples $(N_{s})$ . We examined whether MIMO-NeRF could be used as an alternative to handle this trade-off. + +Datasets. We evaluated the performance using the DONeRF dataset [41] comprising six synthetic indoor and outdoor scenes. Each scene included 300 forward-facing views at a resolution of $800 \times 800$ pixels. $70\%$ , $10\%$ , and $20\%$ of the images were used for training, validation, and testing, respectively. + +Implementation. We implemented the models according to the source code of DONeRF and trained them using the default settings. We applied MIMO-NeRF with $N_{p} = 4$ to DONeRF-16 (i.e., DONeRF with $N_{s} = 16$ ). In the self-supervised learning process, we used two formulations with + +Table 2. Results of ablation studies. Check marks in GS, CL, and AW indicate the use of group shift, 3D consistency loss, and asymmetric weights. In $N_{p} = 2$ , asymmetric weights were not used in the full model because $R^{1} = R^{2} = 1$ . Hence, it was not ablated. + +
ModelPSNR↑FLIP↓# Run↓I-time↓(s)T-time↓(h)# Params(M)
DONeRF-1633.060.061170.4293.790.94
DONeRF-431.210.07050.1403.230.94
MIMO-DONeRF-16/4-naive32.300.06350.1553.260.99
MIMO-DONeRF-16/4-self32.720.06150.1553.560.99
+ +Table 3. Comparison of quantitative scores between DONeRFs and MIMO-DONeRFs. MIMO-DONeRF-16/4-naive outperformed DONeRF-4 in terms of PSNR and FLIP with a small increase in I-time and T-time. The performance of MIMO-DONeRF-16/4-self was close to DONeRF-16 in terms of PSNR and FLIP with shorter I-time and T-time. + +$R^1 = R^2 = 1$ and group shifts. This model is referred to as MIMO-DonNeRF-16/4. We set $\lambda$ to 0.001. As a baseline, we examined DONeRF-4, which had the same # Run as MIMO-DonNeRF-16/4. The implementation details are presented in Appendix B.2. + +Evaluation metrics. Following the study on DONeRF [41], we assessed the image quality using the PSNR and FLIP [1]. In addition, we used the # Run, I-time, T-time, and # Params described in Section 5.1. In DONeRF, # Run was calculated as $1 + \frac{N_s}{N_p}$ . + +Results. The results are summarized in Table 3. It is observed that MIMO-DONeRF-16/4-naive outperformed DONeRF-4 in terms of PSNR and FLIP with a small increase in I-time and T-time. MIMO-DONeRF-16/4-self enhanced the image quality with an increase in T-time, and its image quality approached that of DONeRF-16 in terms of PSNR and FLIP with faster inference and training. These results suggest that the increase in $N_{p}$ (i.e., the replacement of the SISO MLP by the MIMO MLP) can be used as an alternative to the reduction in $N_{s}$ (the number of selected samples) to obtain a better trade-off between speed and quality. A detailed analysis is presented in Appendix A.8. + +# 5.5. Application to TensoRF + +A NeRF with alternative representations is another representative fast approach. To demonstrate that MIMO-NeRF is also compatible with this model, we applied it to TensoRF [9], a representative model in this category. TensoRF uses a vector-matrix decomposition to calculate the volume densities and color features and applies a SISO MLP to the color features to decode the RGB colors. The corresponding ambiguity was relatively limited because the volume densities were extracted using an explicit representation. Hence, we simply replaced the SISO MLP with a MIMO MLP without modifying the training process while prioritizing training speed. These models are denoted as MIMOTensoRF- $N_{p}$ , where $N_{p}$ was varied among $\{2,4,8\}$ . + +Dataset. We examined the performance of our approach on the Blender [39] and LLFF [38] datasets described in Section 5.1. Full-size images were used in this experiment. + +
ModelPSNR↑SSIM↑# Run↓I-time↓(s)T-time↓(m)# Params(M)
TensoRF33.230.9639.951.2511.5018.8
MIMO-TensoRF-233.260.9634.761.1810.8918.8
MIMO-TensoRF-432.980.9612.401.1510.6718.8
MIMO-TensoRF-832.370.9561.271.1410.5718.9
(a) Blender
ModelPSNR↑SSIM↑# Run↓I-time↓(s)T-time↓(m)# Params(M)
TensoRF26.730.837126.736.6423.4146.8
MIMO-TensoRF-226.720.83762.146.1821.6346.8
MIMO-TensoRF-426.720.83630.165.7621.1546.8
MIMO-TensoRF-826.640.83514.525.5220.6846.9
(b) LLFF
+ +Table 4. Comparison of quantitative scores between TensoRF and MIMO-TensoRF. MIMO-TensoRF improved I-time and T-time while retaining PSNR and SSIM when $N_{p} \leq 2$ and $N_{p} \leq 4$ on the Blender and LLFF datasets, respectively. + +Implementation. We implemented the models based on the official source code of $\mathrm{TensoRF^{10}}$ and trained all the models using the same default settings for a fair comparison. The implementation details are presented in Appendix B.3. + +Evaluation metrics. Following the study on TensoRF [9], we measured the image quality using PSNR and SSIM [64]. In addition, we used the # Run, I-time, T-time, and # Params described in Section 5.1. In TensoRF, # Run is determined adaptively for each pixel. Therefore, we report the average value. + +Results. The results are presented in Table 4. It is observed that MIMO-TensoRF improved I-time and T-time with similar image quality when $N_{p}$ was set within an adequate range (in particular, $N_{p} \leq 2$ on the Blender dataset and $N_{p} \leq 4$ on the LLFF dataset). These results suggest that MIMO-TensoRF can strengthen the inference and training speed of TensoRF without negative effects by adequately selecting $N_{p}$ . A detailed analysis is presented in Appendix A.9. + +# 6. Discussion + +The results of these experiments in various situations demonstrate that MIMO-NeRF achieved a good trade-off between speed and quality. However, we also found that the quality degradation became significant with increasing $N_{p}$ . One possible reason for this is that we did not modify the baseline network except for its input and output and did not increase the capacity of the models. It might be natural to implement a model of larger capacity to handle larger combinations of inputs and outputs. We did not adopt this strategy to ensure a fair comparison. However, searching for the best configurations considering the number of samples, the number of groups (the proposed new searching area), and the size of the model remain as a practically imperative and promising direction for further research. + +# 7. Conclusion + +In this study, we have proposed MIMO-NeRF to improve the rendering speed of NeRF. Our core idea is that of replacing the SISO MLP used in standard NeRFs with a MIMO-MLP. We have developed a novel self-supervised learning method to address the ambiguity in the color and volume density of each point without relying on pretrained models. The results of an experimental evaluation have shown that MIMO-NeRF achieves a good trade-off between speed and quality with a reasonable training time. Although we have demonstrated the versatility of MIMO-NeRF by applying it to various NeRFs, many implicit neural representations aside from NeRFs also partially or primarily use SISO MLPs. We expect our ideas to be utilized with a few modifications to speed up the execution of such models. + +# References + +[1] Pontus Andersson, Jim Nilsson, Tomas Akenine-Möller, Magnus Oskarsson, Kalle Åström, and Mark D. Fairchild. FLIP: A difference evaluator for alternating images. Proc. ACM Comput. Graph. Interact. Tech., 3(2), 2020. 8 +[2] Benjamin Attal, Jia-Bin Huang, Michael Zollhoefer, Johannes Kopf, and Changil Kim. Learning neural light fields with ray-space embedding networks. In CVPR, 2022. 3 +[3] Matan Atzmon and Yaron Lipman. SAL: Sign agnostic learning of shapes from raw data. In CVPR, 2020. 3 +[4] Jonathan T. Barron, Ben Mildenhall, Matthew Tancik, Peter Hedman, Ricardo Martin-Brualla, and Pratul P. Srinivasan. Mip-NeRF: A multiscale representation for antiailiasing neural radiance fields. In ICCV, 2021. 3 +[5] Jonathan T. Barron, Ben Mildenhall, Dor Verbin, Pratul P. Srinivasan, and Peter Hedman. Mip-NeRF 360: Unbounded anti-aliased neural radiance fields. In CVPR, 2022. 3 +[6] Rohan Chabra, Jan E. Lenssen, Eddy Ilg, Tanner Schmidt, Julian Straub, Steven Lovegrove, and Richard Newcombe. Deep local shapes: Learning local SDF priors for detailed 3D reconstruction. In ECCV, 2020. 3 +[7] Eric R. Chan, Connor Z. Lin, Matthew A. Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas J. Guibas, Jonathan Tremblay, Sameh Khamis, Tero Karras, and Gordon Wetzstein. Efficient geometry-aware 3D generative adversarial networks. In CVPR, 2022. 2, 3 +[8] Eric R. Chan, Marco Monteiro, Petr Kellnhofer, Jiajun Wu, and Gordon Wetzstein. pi-GAN: Periodic implicit generative adversarial networks for 3D-aware image synthesis. In CVPR, 2021. 3 +[9] Anpei Chen, Zexiang Xu, Andreas Geiger, Jingyi Yu, and Hao Su. TensoRF: Tensorial radiance fields. In ECCV, 2022. 2, 3, 6, 8, 9 +[10] Xingyu Chen, Qi Zhang, Xiaoyu Li, Yue Chen, Ying Feng, Xuan Wang, and Jue Wang. Hallucinated neural radiance fields in the wild. In CVPR, 2022. 3 +[11] Zhiqin Chen and Hao Zhang. Learning implicit fields for generative shape modeling. In CVPR, 2019. 3 + +[12] Julian Chibane, Aymen Mir, and Gerard Pons-Moll. Neural unsigned distance fields for implicit function learning. In NeurIPS, 2020. 3 +[13] Yu Deng, Jiaolong Yang, Jianfeng Xiang, and Xin Tong. GRAM: Generative radiance manifolds for 3D-aware image generation. In CVPR, 2022. 3 +[14] Jiemin Fang, Lingxi Xie, Xinggang Wang, Xiaopeng Zhang, Wenyu Liu, and Qi Tian. NeuSample: Neural sample field for efficient view synthesis. arXiv preprint arXiv:2111.15552, 2021. 2, 3 +[15] Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, 2022. 2, 3 +[16] Guy Gafni, Justus Thies, Michael Zollhofer, and Matthias Nießner. Dynamic neural radiance fields for monocular 4D facial avatar reconstruction. In CVPR, 2021. 3 +[17] Stephan J. Garbin, Marek Kowalski, Matthew Johnson, Jamie Shotton, and Julien Valentin. FastNeRF: High-fidelity neural rendering at 200FPS. In ICCV, 2021. 2, 3 +[18] Kyle Genova, Forrester Cole, Daniel Vlasic, Aaron Sarna, William T. Freeman, and Thomas Funkhouser. Learning shape templates with structured implicit functions. In ICCV, 2019. 3 +[19] Ian J. Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In NIPS, 2014. 3 +[20] Amos Gropp, Lior Yariv, Niv Haim, Matan Atzmon, and Yaron Lipman. Implicit geometric regularization for learning shapes. In ICML, 2020. 3 +[21] Jiatao Gu, Lingjie Liu, Peng Wang, and Christian Theobalt. StyleNeRF: A style-based 3D-aware generator for high-resolution image synthesis. In ICLR, 2022. 3 +[22] Peter Hedman, Pratul P. Srinivasan, Ben Mildenhall, Jonathan T. Barron, and Paul Debevec. Baking neural radiance fields for real-time view synthesis. In ICCV, 2021. 2, 3 +[23] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. In NeurIPS, 2020. 3 +[24] Tao Hu, Shu Liu, Yilun Chen, Tiancheng Shen, and Jiaya Jia. EfficientNeRF: Efficient neural radiance fields. In CVPR, 2022. 2, 3 +[25] Chiyu Max Jiang, Avneesh Sud, Ameesh Makadia, Jingwei Huang, Matthias Nießner, and Thomas Funkhouser. Local implicit grid representations for 3D scenes. In CVPR, 2020. 3 +[26] Takuhiro Kaneko. AR-NeRF: Unsupervised learning of depth and defocus effects from natural images with aperture rendering neural radiance fields. In CVPR, 2022. 3 +[27] Andreas Kurz, Thomas Neff, Zhaoyang Lv, Michael Zollhöfer, and Markus Steinberger. AdaNeRF: Adaptive sampling for real-time rendering of neural radiance fields. In ECCV, 2022. 2, 3 +[28] Chen-Hsuan Lin, Chaoyang Wang, and Simon Lucey. SDF-SRN: Learning signed distance 3D object reconstruction from static images. In NeurIPS, 2020. 1, 3 + +[29] David B. Lindell, Julien N. P. Martel, and Gordon Wetzstein. AutoInt: Automatic integration for fast neural volume rendering. In CVPR, 2021. 2, 3 +[30] Lingjie Liu, Jiatao Gu, Kyaw Zaw Lin, Tat-Seng Chua, and Christian Theobalt. Neural sparse voxel fields. In NeurIPS, 2020. 2, 3 +[31] Shichen Liu, Shunsuke Saito, Weikai Chen, and Hao Li. Learning to infer implicit surfaces without 3D supervision. In NeurIPS, 2019. 3 +[32] Shaohui Liu, Yinda Zhang, Songyou Peng, Boxin Shi, Marc Pollefeys, and Zhaopeng Cui. DIST: Rendering deep implicit signed distance function with differentiable sphere tracing. In CVPR, 2020. 3 +[33] Ricardo Martin-Brualla, Noha Radwan, Mehdi S. M. Sajjadi, Jonathan T. Barron, Alexey Dosovitskiy, and Daniel Duckworth. NeRF in the wild: Neural radiance fields for unconstrained photo collections. In CVPR, 2021. 3 +[34] Nelson Max. Optical models for direct volume rendering. IEEE Trans. Vis. Comput. Graph., 1(2), 1995. 1, 3, 4 +[35] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3D reconstruction in function space. In CVPR, 2019. 3 +[36] Mateusz Michalkiewicz, Jhony K. Pontes, Dominic Jack, Mahsa Baktashmotlagh, and Anders Eriksson. Implicit surface representations as layers in neural networks. In ICCV, 2019. 3 +[37] Ben Mildenhall, Peter Hedman, Ricardo Martin-Brualla, Pratul P. Srinivasan, and Jonathan T. Barron. NeRF in the dark: High dynamic range view synthesis from noisy raw images. In CVPR, 2022. 3 +[38] Ben Mildenhall, Pratul P. Srinivasan, Rodrigo Ortiz-Cayon, Nima Khademi Kalantari, Ravi Ramamoorthi, Ren Ng, and Abhishek Kar. Local light field fusion: Practical view synthesis with prescriptive sampling guidelines. ACM Trans. Graph., 38(4), 2019. 6, 8 +[39] Ben Mildenhall, Pratul P. Srinivasan, Matthew Tancik, Jonathan T. Barron, Ravi Ramamoorthi, and Ren Ng. NeRF: Representing scenes as neural radiance fields for view synthesis. In ECCV, 2020. 1, 3, 6, 8 +[40] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Trans. Graph., 41(4), 2022. 2, 3 +[41] Thomas Neff, Pascal Stadlbauer, Mathias Parger, Andreas Kurz, Joerg H. Mueller, Chakravarty R. Alla Chaitanya, Anton Kaplanyan, and Markus Steinberger. DONeRF: Towards real-time rendering of compact neural radiance fields using depth oracle networks. Comput. Graph. Forum, 40(4), 2021. 2, 3, 6, 8 +[42] Michael Niemeyer and Andreas Geiger. CAMPARI: Camera-aware decomposed generative neural radiance fields. In 3DV, 2021. 3 +[43] Michael Niemeyer and Andreas Geiger. GIRAFFE: Representing scenes as compositional generative neural feature fields. In CVPR, 2021. 3 + +[44] Michael Niemeyer, Lars Mescheder, Michael Oechsle, and Andreas Geiger. Differentiable volumetric rendering: Learning implicit 3D representations without 3D supervision. In CVPR, 2020. 1, 3 +[45] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. DeepSDF: Learning continuous signed distance functions for shape representation. In CVPR, 2019. 3 +[46] Songyou Peng, Michael Niemeyer, Lars Mescheder, Marc Pollefeys, and Andreas Geiger. Convolutional occupancy networks. In ECCV, 2020. 3 +[47] Martin Piala and Ronald Clark. TermiNeRF: Ray termination prediction for efficient neural rendering. In 3DV, 2021. 2, 3 +[48] Ben Poole, Ajay Jain, Jonathan T. Barron, and Ben Mildenhall. DreamFusion: Text-to-3D using 2D diffusion. In ICLR, 2023. 3 +[49] Albert Pumarola, Enric Corona, Gerard Pons-Moll, and Francesc Moreno-Noguer. D-NeRF: Neural radiance fields for dynamic scenes. In CVPR, 2021. 3 +[50] Daniel Rebain, Wei Jiang, Soroosh Yazdani, Ke Li, Kwang Moo Yi, and Andrea Tagliasacchi. DeRF: Decomposed radiance fields. In CVPR, 2021. 2, 3 +[51] Christian Reiser, Songyou Peng, Yiyi Liao, and Andreas Geiger. KiloNeRF: Speeding up neural radiance fields with thousands of tiny MLPs. In ICCV, 2021. 2, 3 +[52] Shunsuke Saito, Zeng Huang, Ryota Natsume, Shigeo Morishima, Angjoo Kanazawa, and Hao Li. PIFu: Pixel-aligned implicit function for high-resolution clothed human digitization. In ICCV, 2019. 3 +[53] Katja Schwarz, Yiyi Liao, Michael Niemeyer, and Andreas Geiger. GRAF: Generative radiance fields for 3D-aware image synthesis. In NeurIPS, 2020. 3 +[54] Vincent Sitzmann, Julien Martel, Alexander Bergman, David Lindell, and Gordon Wetzstein. Implicit neural representations with periodic activation functions. In NeurIPS, 2020. 3 +[55] Vincent Sitzmann, Semon Rezchikov, Bill Freeman, Josh Tenenbaum, and Fredo Durand. Light field networks: Neural scene representations with single-evaluation rendering. In NeurIPS, 2021. 1, 3 +[56] Vincent Sitzmann, Michael Zollhöfer, and Gordon Wetzstein. Scene representation networks: Continuous 3D-structure-aware neural scene representations. In NeurIPS, 2019. 1, 3 +[57] Ivan Skorokhodov, Sergey Tulyakov, Yiqun Wang, and Peter Wonka. EpiGRAF: Rethinking training of 3D GANs. In NeurIPS, 2022. 3 +[58] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. In NeurIPS, 2019. 3 +[59] Mohammed Suhail, Carlos Esteves, Leonid Sigal, and Ameesh Makadia. Light field neural rendering. In CVPR, 2022. 3 +[60] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In CVPR, 2022. 2, 3 + +[61] Matthew Tancik, Pratul P. Srinivasan, Ben Mildenhall, Sara Fridovich-Keil, Nithin Raghavan, Utkarsh Singhal, Ravi Ramamoorthi, Jonathan T. Barron, and Ren Ng. Fourier features let networks learn high frequency functions in low dimensional domains. In NeurIPS, 2020. 3 +[62] Dor Verbin, Peter Hedman, Ben Mildenhall, Todd Zickler, Jonathan T. Barron, and Pratul P. Srinivasan. Ref-NeRF: Structured view-dependent appearance for neural radiance fields. In CVPR, 2022. 3 +[63] Huan Wang, Jian Ren, Zeng Huang, Kyle Olszewski, Mengei Chai, Yun Fu, and Sergey Tulyakov. R2L: Distilling neural radiance field to neural light field for efficient novel view synthesis. In ECCV, 2022. 3 +[64] Zhou Wang, Alan C. Bovik, Hamid R. Sheikh, and Eero P. Simoncelli. Image quality assessment: From error visibility to structural similarity. IEEE Trans. Image Process., 13(4), 2004. 6, 9 +[65] Suttisak Wizadwongsa, Pakkapon Phongthawee, Jiraphon Yenphraphai, and Supasorn Suwajanakorn. NeX: Real-time view synthesis with neural basis expansion. In CVPR, 2021. 2, 3 +[66] Liwen Wu, Jae Yong Lee, Anand Bhattachad, Yu-Xiong Wang, and David Forsyth. DIVeR: Real-time and accurate neural radiance fields with deterministic integration for volume rendering. In CVPR, 2022. 2, 3 +[67] Wenqi Xian, Jia-Bin Huang, Johannes Kopf, and Changil Kim. Space-time neural irradiance fields for free-viewpoint video. In CVPR, 2021. 3 +[68] Yang Xue, Yuheng Li, Krishna Kumar Singh, and Yong Jae Lee. GIRAFFE HD: A high-resolution 3D-aware generative model. In CVPR, 2022. 3 +[69] Lior Yariv, Yoni Kasten, Dror Moran, Meirav Galun, Matan Atzmon, Basri Ronen, and Yaron Lipman. Multiview neural surface reconstruction by disentangling geometry and appearance. In NeurIPS, 2020. 1, 3 +[70] Alex Yu, Ruilong Li, Matthew Tancik, Hao Li, Ren Ng, and Angjoo Kanazawa. PlenOctrees for real-time rendering of neural radiance fields. In ICCV, 2021. 2, 3 +[71] Alex Yu, Vickie Ye, Matthew Tancik, and Angjoo Kanazawa. PixelNeRF: Neural radiance fields from one or few images. In CVPR, 2021. 1, 3 +[72] Kai Zhang, Gernot Riegler, Noah Snavely, and Vladlen Koltun. NeRF++: Analyzing and improving neural radiance fields. arXiv preprint arXiv:2010.07492, 2020.3 +[73] Richard Zhang, Phillip Isola, Alexei A. Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In CVPR, 2018. 6 \ No newline at end of file diff --git a/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/images.zip b/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..c9bfd54ce24c61c46dd3f29d37aeacde80772d80 --- /dev/null +++ b/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:8382d1ccdf549eab79ebe18ee442bf17023a861ba1fddf80e1c58a87d979dc70 +size 446195 diff --git a/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/layout.json b/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..cd516b8e2c46ebedfe904cb8db6308fb90d0d9ab --- /dev/null +++ b/2023/MIMO-NeRF_ Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields/layout.json @@ -0,0 +1,11221 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 129, + 103, + 465, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 129, + 103, + 465, + 140 + ], + "spans": [ + { + "bbox": [ + 129, + 103, + 465, + 140 + ], + "type": "text", + "content": "MIMO-NeRF: Fast Neural Rendering with Multi-input Multi-output Neural Radiance Fields" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 146, + 161, + 447, + 190 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 161, + 447, + 190 + ], + "spans": [ + { + "bbox": [ + 146, + 161, + 447, + 190 + ], + "type": "text", + "content": "Takuhiro Kaneko \nNTT Communication Science Laboratories, NTT Corporation" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 217, + 192, + 229 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 217, + 192, + 229 + ], + "spans": [ + { + "bbox": [ + 143, + 217, + 192, + 229 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 243, + 290, + 542 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 243, + 290, + 542 + ], + "spans": [ + { + "bbox": [ + 47, + 243, + 290, + 542 + ], + "type": "text", + "content": "Neural radiance fields (NeRFs) have shown impressive results for novel view synthesis. However, they depend on the repetitive use of a single-input single-output multilayer perceptron (SISO MLP) that maps 3D coordinates and view direction to the color and volume density in a sample-wise manner, which slows the rendering. We propose a multi-input multi-output NeRF (MIMO-NeRF) that reduces the number of MLPs running by replacing the SISO MLP with a MIMO MLP and conducting mappings in a group-wise manner. One notable challenge with this approach is that the color and volume density of each point can differ according to a choice of input coordinates in a group, which can lead to some notable ambiguity. We also propose a self-supervised learning method that regularizes the MIMO MLP with multiple fast reformulated MLPs to alleviate this ambiguity without using pretrained models. The results of a comprehensive experimental evaluation including comparative and ablation studies are presented to show that MIMO-NeRF obtains a good trade-off between speed and quality with a reasonable training time. We then demonstrate that MIMO-NeRF is compatible with and complementary to previous advancements in NeRFs by applying it to two representative fast NeRFs, i.e., a NeRF with a sampling network (DONeRF) and a NeRF with alternative representations (TensoRF)." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 566, + 128, + 578 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 566, + 128, + 578 + ], + "spans": [ + { + "bbox": [ + 47, + 566, + 128, + 578 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 586, + 287, + 671 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 586, + 287, + 671 + ], + "spans": [ + { + "bbox": [ + 47, + 586, + 287, + 671 + ], + "type": "text", + "content": "Images are two-dimensional (2D) projections of three-dimensional (3D) scenes. Solving the inverse problem, that is, learning 3D representations from 2D images and synthesizing novel views, is a fundamental concern in computer vision and graphics and has been extensively studied for various applications such as photo editing, content creation, virtual reality, and environmental understanding." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 59, + 671, + 287, + 684 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 671, + 287, + 684 + ], + "spans": [ + { + "bbox": [ + 59, + 671, + 287, + 684 + ], + "type": "text", + "content": "With the advent of implicit neural representations" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 307, + 215, + 426, + 305 + ], + "blocks": [ + { + "bbox": [ + 307, + 215, + 426, + 305 + ], + "lines": [ + { + "bbox": [ + 307, + 215, + 426, + 305 + ], + "spans": [ + { + "bbox": [ + 307, + 215, + 426, + 305 + ], + "type": "image", + "image_path": "da7cd6167e4c90517e2d9806f52c9dd8930bae0734d742314d72b4bb0c0f1f1b.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 351, + 308, + 383, + 319 + ], + "lines": [ + { + "bbox": [ + 351, + 308, + 383, + 319 + ], + "spans": [ + { + "bbox": [ + 351, + 308, + 383, + 319 + ], + "type": "text", + "content": "(a) NeRF" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 426, + 215, + 545, + 305 + ], + "blocks": [ + { + "bbox": [ + 426, + 215, + 545, + 305 + ], + "lines": [ + { + "bbox": [ + 426, + 215, + 545, + 305 + ], + "spans": [ + { + "bbox": [ + 426, + 215, + 545, + 305 + ], + "type": "image", + "image_path": "0172601d03809291881bba5f36c935b4b3388c06f4ac60bfa296da32699e1cac.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 436, + 308, + 534, + 319 + ], + "lines": [ + { + "bbox": [ + 436, + 308, + 534, + 319 + ], + "spans": [ + { + "bbox": [ + 436, + 308, + 534, + 319 + ], + "type": "text", + "content": "(b) MIMO-NeRF (proposed)" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 304, + 331, + 547, + 475 + ], + "lines": [ + { + "bbox": [ + 304, + 331, + 547, + 475 + ], + "spans": [ + { + "bbox": [ + 304, + 331, + 547, + 475 + ], + "type": "text", + "content": "Figure 1. Comparison between NeRF and MIMO-NeRF (proposed). (a) A typical NeRF uses a SISO MLP that maps 3D coordinates and view direction to the color and volume density in a sample-wise manner. (b) In contrast, the proposed MIMO-NeRF uses a MIMO MLP that performs mappings in a group-wise manner. This change reduces the number of MLPs running and improves the rendering speed, but also requires addressing ambiguity in the color and volume density caused by the fact that these values are determined in a non-unique manner by a set of input coordinates that vary by viewpoint, grouping, and sampling. The main technical contribution of the present work is that of providing methods to mitigate this challenge. We demonstrate the impact of the proposed technique in Figure 2." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 496, + 547, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 496, + 547, + 616 + ], + "spans": [ + { + "bbox": [ + 304, + 496, + 547, + 616 + ], + "type": "text", + "content": "(e.g., [56, 44, 39, 28, 69, 71, 55]), substantial advancements have been made towards addressing this problem. Neural radiance fields (NeRFs) [39] have been noted as a successful approach. A NeRF represents a scene using a continuous function that maps 3D coordinates and view direction to the color and volume density and renders a pixel by integrating the outputs on a ray using volume rendering [34]. This formulation enables NeRF to learn to synthesize geometrically consistent and high-fidelity novel views with only 2D supervision." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 617, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 547, + 714 + ], + "type": "text", + "content": "Despite this advantage, a typical NeRF suffers from slow rendering because it uses a single-input single-output (SISO) MLP that calculates the RGB color and volume density in a sample-wise manner (Figure 1(a)). Although this architecture ensures the independent representation of each point, which is useful, for example, for learning view-independent volume density, its computational cost increases in proportion to the number of samples for each" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 693, + 286, + 715 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 693, + 286, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 693, + 286, + 715 + ], + "type": "text", + "content": "1The project page is available at https://www.Kecl.ntt.co.jp/people/kaneko.takuhiro/projects/mimo-nerf/." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3273" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": "ray (e.g., on the order of hundreds). Several methods developed to address this issue can be roughly categorized into two approaches, including (1) sample reduction and (2) alternative representations." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 121, + 288, + 276 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 121, + 288, + 276 + ], + "spans": [ + { + "bbox": [ + 46, + 121, + 288, + 276 + ], + "type": "text", + "content": "A typical sample reduction strategy reduces the number of samples on a ray using a sampling network based on the depth [41] or density of a pretrained NeRF [47] or using a sampling network with an adaptive optimization mechanism [29, 14, 27]. These methods successfully accelerate the rendering process while retaining the quality of an image adequately. However, most of these techniques still use a SISO MLP to predict the colors and volume densities of selected samples; therefore, they still need to run MLPs many times in proportion to the number of selected samples. This issue can be alleviated by reducing the number of selected samples, although this deteriorates the quality of the synthesized images accordingly." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 276, + 288, + 432 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 276, + 288, + 432 + ], + "spans": [ + { + "bbox": [ + 46, + 276, + 288, + 432 + ], + "type": "text", + "content": "As alternative representations, various sophisticated and faster representations such as 3D voxel grids [17, 22, 30, 66, 60], sparse voxel-based octrees [70, 15], multiplane images [65], tri-planes [7], vector-matrix decomposition [9], hashes [40], NeRF-specific structures [24], and space-wise MLPs [50, 51] have been devised. These representations contribute to achieving fast rendering while retaining image quality moderately well. However, after powerful features are extracted using alternative representations, SISO MLPs are still commonly used for the final prediction of color or volume density owing to their memory-efficient and continuous nature. Hence, part of the calculation cost still increases depending on the number of samples." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 432, + 287, + 635 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 432, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 46, + 432, + 287, + 635 + ], + "type": "text", + "content": "Consequently, owing to its compact, continuous (i.e., resolution-free), and independent (e.g., view-independent) nature, a SISO MLP is commonly used in various NeRFs. However, as mentioned above, the calculation cost increases with the number of samples. This is not preferable when considering the improvement in rendering speed. Possible simple solutions include, for example, a reduction of the number of samples or a reduction of the size of a model with a corresponding sacrifice of image quality. However, these solutions are not necessarily the best for handling the tradeoff between quality and speed. Alternatively, we propose a multi-input multi-output NeRF (MIMO-NeRF), which is a novel variant of NeRF that represents a scene using a MIMO MLP that conducts mappings in a group-wise manner (Figure 1(b)). This modification enables a reduction in the number of MLPs running according to the number of grouped samples and consequently improves rendering speed." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 635, + 288, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 635, + 288, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 635, + 288, + 696 + ], + "type": "text", + "content": "However, in this approach, the uniqueness of the color and volume density of each point is not ensured because they are determined not only by the coordinates of the corresponding point but also by the coordinates of the other points in a group, which vary by viewpoint, grouping, and" + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 310, + 70, + 544, + 175 + ], + "blocks": [ + { + "bbox": [ + 310, + 70, + 544, + 175 + ], + "lines": [ + { + "bbox": [ + 310, + 70, + 544, + 175 + ], + "spans": [ + { + "bbox": [ + 310, + 70, + 544, + 175 + ], + "type": "image", + "image_path": "f456a4e5b7fbb311e92d30b9fe46fcd072e7686ff936ab9c219de744be5a1438.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 184, + 545, + 251 + ], + "lines": [ + { + "bbox": [ + 304, + 184, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 304, + 184, + 545, + 251 + ], + "type": "text", + "content": "Figure 2. Challenge of training MIMO-NeRF and the impact of the proposed self-supervised learning. (a) MIMO-NeRF-naive suffers from ambiguity in the color and volume density of each point and deteriorates image quality. (b) We propose self-supervised learning to address this problem without relying on a pretrained model. This technique improves image quality." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 271, + 546, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 271, + 546, + 521 + ], + "spans": [ + { + "bbox": [ + 304, + 271, + 546, + 521 + ], + "type": "text", + "content": "sampling. This leads to some ambiguity and causes fluctuation artifacts as shown in Figure 2(a). In particular, this ambiguity can be problematic when learning a 3D representation using only 2D supervision because obtaining direct supervision that can resolve the ambiguity is difficult. One possible solution is to train a standard (i.e., SISO) NeRF first and then distill the model onto the corresponding MIMO-NeRF. However, this increases training time because both student and teacher NeRFs must be trained. Alternatively, we have also developed a novel self-supervised learning approach in which we reformulate a MIMO MLP in several ways (in particular, we use group shift (Figure 3) and variation reduction (Figure 4)) and impose a consistent regularization so that the reformulated MIMO MLPs produce the same outputs. Because each reformulated MIMO MLP can render a pixel faster than the original SISO MLP, we can prevent a large sacrifice of training time even when using multiple reformulated MIMO MLPs by adequately adjusting the reformulation configuration. Figure 2(b) shows an example of the effects of this learning scheme." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 523, + 545, + 654 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 523, + 545, + 654 + ], + "spans": [ + { + "bbox": [ + 304, + 523, + 545, + 654 + ], + "type": "text", + "content": "We investigated the benchmark performance of MIMO-NeRF by comparing it with possible alternatives (including the distillation of a pretrained NeRF, sample reduction, and reduction of the model size). We also performed ablation studies to examine the validity of each component of the proposed self-supervised learning method. We apply MiMO-NeRF to two representative fast NeRFs, including a NeRF with a sampling network (DONeRF [41]) and a model with alternative representations (TensoRF [9]) to demonstrate that it is compatible with and complementary to previous advancements in NeRFs." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 655, + 545, + 678 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 655, + 545, + 678 + ], + "spans": [ + { + "bbox": [ + 306, + 655, + 545, + 678 + ], + "type": "text", + "content": "The main contributions of this study are summarized as follows." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 317, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 317, + 689, + 545, + 713 + ], + "type": "text", + "content": "- To speed up the rendering of NeRF, we propose MIMO-NeRF, which represents a scene using a MIMO" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 58, + 702, + 219, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 219, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 219, + 712 + ], + "type": "text", + "content": "2We discuss this trade-off in detail in Section 5.2." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3274" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 66, + 72, + 286, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 286, + 95 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 286, + 95 + ], + "type": "text", + "content": "MLP that maps the coordinates on a ray to the colors and volume densities in a group-wise manner." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 59, + 99, + 286, + 221 + ], + "type": "list", + "angle": 0, + "index": 3, + "blocks": [ + { + "bbox": [ + 59, + 99, + 286, + 146 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 99, + 286, + 146 + ], + "spans": [ + { + "bbox": [ + 59, + 99, + 286, + 146 + ], + "type": "text", + "content": "- We introduce novel self-supervised learning to mitigate the ambiguity in the color and volume density of each point and enable MIMO-NeRF to be trained without relying on pretrained models." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 59, + 150, + 286, + 221 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 150, + 286, + 221 + ], + "spans": [ + { + "bbox": [ + 59, + 150, + 286, + 221 + ], + "type": "text", + "content": "- We examined the effectiveness of MIMO-NeRF through a comprehensive experimental evaluation, and the results demonstrate the versatility of MIMO-NeRF in applications to two representative fast NeRFs. We also provide more detailed analyses and extended results in the Supplementary Material." + } + ] + } + ], + "index": 2 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 47, + 232, + 130, + 244 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 232, + 130, + 244 + ], + "spans": [ + { + "bbox": [ + 47, + 232, + 130, + 244 + ], + "type": "text", + "content": "2. Related work" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 252, + 286, + 431 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 252, + 286, + 431 + ], + "spans": [ + { + "bbox": [ + 47, + 252, + 286, + 431 + ], + "type": "text", + "content": "Implicit neural representations. Implicit neural representations have attracted attention in 3D shape [45, 35, 11, 36, 52, 18, 3, 20] and 3D scene [25, 46, 6, 12, 54] reconstructions owing to their memory-efficient, continuous (i.e., resolution-free), and 3D-aware characteristics. Although research began with explicit 3D supervision, learning implicit 3D only from 2D supervision (i.e., inverse graphics) has also been achieved by incorporating differentiable rendering [56, 31, 44, 32, 39, 28, 69, 71, 55]. In this study, we focus on NeRFs as a representative example of the latter owing to their remarkable success in synthesizing geometrically consistent and high-quality novel view. However, applying our ideas to other implicit neural representations, such as those mentioned above, remains as an interesting direction for future research." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 435, + 286, + 662 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 435, + 286, + 662 + ], + "spans": [ + { + "bbox": [ + 47, + 435, + 286, + 662 + ], + "type": "text", + "content": "Advancements in NeRFs. Various extensions have been proposed since the emergence of NeRF. For example, representative research topics include (1) improving image quality and enhancing applicable scenes (e.g., [72, 33, 49, 16, 67, 4, 5, 37, 62, 10]), (2) incorporation into other models, e.g., deep generative models, such as generative adversarial networks (GANs) [19] and diffusion probabilistic models [58, 23] (e.g., [53, 8, 43, 42, 21, 7, 13, 68, 26, 57, 48]), and (3) accelerating NeRFs for fast inference or fast training (e.g., [41, 47, 29, 14, 27, 17, 22, 30, 66, 60, 70, 15, 65, 7, 9, 40, 24, 50, 51]). The present work falls into the third category. However, our proposed approach is complementary to previous studies, including most of the abovementioned works in all categories, because SISO MLPs have commonly been used as a partial or main network in previous studies and improving their rendering speed by replacing SISO MLPs with the proposed MIMO MLP is feasible. The results of the experimental evaluation validated this potential (Sections 5.4 and 5.5)." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 665, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 665, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 665, + 286, + 713 + ], + "type": "text", + "content": "Acceleration of NeRFs. As discussed in Section 1, a typical NeRF is well known for its slow rendering because it use a SISO MLP. Several approaches have been developed to address this issue. These can be roughly categorized" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 72, + 545, + 384 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 384 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 384 + ], + "type": "text", + "content": "into two approaches, including (1) sample reduction and (2) alternative representations. (1) As described in Section 1, methods that reduce the number of samples using a sampling network can improve rendering speed by replacing a SISO MLP with the proposed MIMO MLP. We validated this statement during an experiment (Section 5.4) by applying our ideas to a representative NeRF in this category (DONeRF [41]). Another common approach in the first category is to render pixels using a light-field network [55, 2, 59, 63] instead of volume rendering [34]. This approach has been shown to achieve fast rendering by running only a single MLP for a given ray. However, owing to the lack of explicit geometry-aware representations driven by the use of volume densities, these methods suffer from limitations that are not faced by a standard NeRF in terms of restrictions on applicable scenes (e.g., toy datasets [55] and forward-facing datasets [2]), a requirement for high-capacity models (e.g., a deeper MLP [63] and a transformer [59]), and the need for extra modules (e.g., metalearned priors [55], pretrained NeRFs [2, 63], or additional encoders [59]). (2) As explained in Section 1, alternative representations have the potential to accelerate the rendering speed by replacing the SISO MLP with the proposed MIMO MLP. We present an empirical investigation of this potential in Section 5.5 by incorporating MIMO-NeRF into TensoRF [9], a representative model in this category." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 385, + 545, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 385, + 545, + 529 + ], + "spans": [ + { + "bbox": [ + 304, + 385, + 545, + 529 + ], + "type": "text", + "content": "Learning of fast NeRFs. Knowledge distillation (or baking) methods are commonly used to train fast NeRFs. In these methods, a standard NeRF is first trained and then baked to faster representations [17, 22, 24, 50, 51]. However, this approach is disadvantageous in terms of training time because two separate models must be trained, i.e., teacher and student NeRFs. As an alternative, we consider a self-supervised learning approach in which we can train a model without a large increase in training time. We examine the performance differences between the proposed self-supervised learning scheme and a knowledge distillation scheme in Section 5.1." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 537, + 427, + 550 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 537, + 427, + 550 + ], + "spans": [ + { + "bbox": [ + 306, + 537, + 427, + 550 + ], + "type": "text", + "content": "3. Preliminaries: NeRF" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "type": "text", + "content": "We begin by explaining NeRFs as the basis for our model. As shown in Figure 1(a), a NeRF represents a point in a 3D space using a continuous SISO function " + }, + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{SISO}}" + }, + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "type": "text", + "content": " that maps the 3D position " + }, + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "type": "inline_equation", + "content": "\\mathbf{x} \\in \\mathbb{R}^3" + }, + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "type": "text", + "content": " and view direction " + }, + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "type": "inline_equation", + "content": "\\mathbf{d} \\in \\mathbb{S}^2" + }, + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "type": "text", + "content": " to the RGB color " + }, + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "type": "inline_equation", + "content": "\\mathbf{c}(\\mathbf{x}, \\mathbf{d}) \\in \\mathbb{R}^3" + }, + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "type": "text", + "content": " and volume density " + }, + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "type": "inline_equation", + "content": "\\sigma(\\mathbf{x}) \\in \\mathbb{R}^+" + }, + { + "bbox": [ + 304, + 558, + 545, + 630 + ], + "type": "text", + "content": " in a sample-wise manner." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 322, + 634, + 545, + 648 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 322, + 634, + 545, + 648 + ], + "spans": [ + { + "bbox": [ + 322, + 634, + 545, + 648 + ], + "type": "interline_equation", + "content": "f _ {\\mathrm {S I S O}}: \\mathbb {R} ^ {3} \\times \\mathbb {S} ^ {2} \\rightarrow \\mathbb {R} ^ {3} \\times \\mathbb {R} ^ {+}, (\\mathbf {x}, \\mathbf {d}) \\mapsto (\\mathbf {c}, \\sigma). \\tag {1}", + "image_path": "cde2e8a7375368b90bacc4d68439116bc16a148442bd6e0214e262adc743183f.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "Specifically, positional encoding [39, 61] is applied to " + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{d}" + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": " to represent the high-frequency details of an image. Subsequently, an MLP is applied to the encoded inputs to obtain " + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{c}" + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": ". For simplicity, we represent these series of processes in a unified manner as " + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{SISO}}" + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3275" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "text", + "content": "A NeRF is based on ray tracing, in which a camera ray is defined as " + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "inline_equation", + "content": "\\mathbf{r}(t) = \\mathbf{o} + t\\mathbf{d}" + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "inline_equation", + "content": "\\mathbf{o}" + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "inline_equation", + "content": "\\mathbf{d}" + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "text", + "content": " respectively denote the origin and direction of the camera and " + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "text", + "content": " denotes a distance from the origin. A NeRF calculates the color of each pixel " + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{C}}(\\mathbf{r})" + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "text", + "content": " by integrating the colors and volume densities on a ray " + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "inline_equation", + "content": "\\mathbf{r}(t)" + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "text", + "content": " within " + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "inline_equation", + "content": "t \\in [t_n, t_f]" + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "text", + "content": " using volume rendering [34]. In implementation, the calculation of the integral is intractable; therefore, a ray is discretized into " + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "text", + "content": " points; alternatively, the following discretized formulation can be used." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 73, + 198, + 287, + 232 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 73, + 198, + 287, + 232 + ], + "spans": [ + { + "bbox": [ + 73, + 198, + 287, + 232 + ], + "type": "interline_equation", + "content": "\\hat {\\mathbf {C}} (\\mathbf {r}) = \\sum_ {i = 1} ^ {N} T _ {i} \\alpha_ {i} \\mathbf {c} _ {i}, \\text {w h e r e} T _ {i} = \\prod_ {j = 1} ^ {i - 1} (1 - \\alpha_ {j}), \\tag {2}", + "image_path": "c2d8aa064954bd00023bf431c3e1219d3fcccd4807e47ff9b0783974fcbee2be.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "spans": [ + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": "where the subscript " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": " indicates that the variable corresponds to the " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": "-th point on a ray, " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "\\alpha_{i} = 1 - \\exp (-\\sigma_{i}\\delta_{i})" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": " is an alpha value, and " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "\\delta_{i} = t_{i + 1} - t_{i}" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": " is the distance between the " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": "-th and " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "(i + 1)" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": "-th points. " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{SISO}}" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": " is optimized by minimizing the following pixel-wise loss." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 112, + 308, + 287, + 323 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 112, + 308, + 287, + 323 + ], + "spans": [ + { + "bbox": [ + 112, + 308, + 287, + 323 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {p i x e l}} = \\| \\hat {\\mathbf {C}} (\\mathbf {r}) - \\mathbf {C} (\\mathbf {r}) \\| _ {2} ^ {2}, \\tag {3}", + "image_path": "b9d677478c3bd6d580eb57d68791b7ba4e634fc882cf07a7947043b53142b2f1.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 331, + 287, + 366 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 331, + 287, + 366 + ], + "spans": [ + { + "bbox": [ + 46, + 331, + 287, + 366 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 331, + 287, + 366 + ], + "type": "inline_equation", + "content": "\\mathbf{C}(\\mathbf{r})" + }, + { + "bbox": [ + 46, + 331, + 287, + 366 + ], + "type": "text", + "content": " is the ground-truth color for a ray " + }, + { + "bbox": [ + 46, + 331, + 287, + 366 + ], + "type": "inline_equation", + "content": "\\mathbf{r}" + }, + { + "bbox": [ + 46, + 331, + 287, + 366 + ], + "type": "text", + "content": ". In practice, this loss is calculated for " + }, + { + "bbox": [ + 46, + 331, + 287, + 366 + ], + "type": "inline_equation", + "content": "\\mathbf{r} \\in \\mathcal{R}" + }, + { + "bbox": [ + 46, + 331, + 287, + 366 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 331, + 287, + 366 + ], + "type": "inline_equation", + "content": "\\mathcal{R}" + }, + { + "bbox": [ + 46, + 331, + 287, + 366 + ], + "type": "text", + "content": " denotes a set of rays in each batch." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "spans": [ + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "text", + "content": "In practice, a NeRF uses coarse and fine networks. In the coarse network, a ray is discretized into " + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "inline_equation", + "content": "N_{c}" + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "text", + "content": " points using stratified sampling, whereas in the fine network, a ray is discretized into " + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "inline_equation", + "content": "N_{c} + N_{f}" + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "text", + "content": " points using hierarchical sampling in which " + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "inline_equation", + "content": "N_{f}" + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "text", + "content": " additional points are sampled according to the output of the coarse network. The two networks are optimized by minimizing " + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{pixel}}" + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "text", + "content": " for " + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{C}}(\\mathbf{r})" + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "text", + "content": " predicted by each network. Hereafter, we omit a variable in parentheses (e.g., " + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "inline_equation", + "content": "(\\mathbf{r})" + }, + { + "bbox": [ + 46, + 367, + 287, + 475 + ], + "type": "text", + "content": ") for simplicity." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 485, + 133, + 498 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 485, + 133, + 498 + ], + "spans": [ + { + "bbox": [ + 47, + 485, + 133, + 498 + ], + "type": "text", + "content": "4. MIMO-NeRF" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 505, + 162, + 517 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 505, + 162, + 517 + ], + "spans": [ + { + "bbox": [ + 47, + 505, + 162, + 517 + ], + "type": "text", + "content": "4.1. MIMO formulation" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 523, + 287, + 643 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 523, + 287, + 643 + ], + "spans": [ + { + "bbox": [ + 46, + 523, + 287, + 643 + ], + "type": "text", + "content": "There are several ways to group the input samples when constructing a MIMO MLP. For example, we can construct a general MLP that can accept any combination of samples in a 3D space, or we can construct a specific MLP that only accepts a group of nearby samples. In preliminary experiments (Appendix A.1), we found that the latter significantly outperformed the former because general models are more difficult to train than more specific models. Therefore, we adopted the latter in this study. In particular, we group neighboring samples on a ray as shown in Figure 1(b).3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 643, + 287, + 667 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 643, + 287, + 667 + ], + "spans": [ + { + "bbox": [ + 46, + 643, + 287, + 667 + ], + "type": "text", + "content": "More formally, given " + }, + { + "bbox": [ + 46, + 643, + 287, + 667 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 643, + 287, + 667 + ], + "type": "text", + "content": " samples on a ray, we group " + }, + { + "bbox": [ + 46, + 643, + 287, + 667 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 46, + 643, + 287, + 667 + ], + "type": "text", + "content": " samples from the sample nearest to the camera and create" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 72, + 545, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 545, + 96 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 545, + 96 + ], + "type": "inline_equation", + "content": "N / N_{p}" + }, + { + "bbox": [ + 306, + 72, + 545, + 96 + ], + "type": "text", + "content": " groups. Subsequently, we apply a MIMO function " + }, + { + "bbox": [ + 306, + 72, + 545, + 96 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{MIMO}}" + }, + { + "bbox": [ + 306, + 72, + 545, + 96 + ], + "type": "text", + "content": " to each group as follows." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 319, + 101, + 545, + 130 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 319, + 101, + 545, + 130 + ], + "spans": [ + { + "bbox": [ + 319, + 101, + 545, + 130 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} f _ {\\mathrm {M I M O}}: (\\mathbb {R} ^ {3}) ^ {N _ {p}} \\times \\mathbb {S} ^ {2} \\rightarrow (\\mathbb {R} ^ {3} \\times \\mathbb {R} ^ {+}) ^ {N _ {p}}, \\\\ \\left(\\mathbf {x} _ {i}, \\dots , \\mathbf {x} _ {j}, \\mathbf {d}\\right) \\mapsto \\left(\\mathbf {c} _ {i}, \\dots , \\mathbf {c} _ {j}, \\sigma_ {i}, \\dots , \\sigma_ {j}\\right), \\tag {4} \\\\ \\end{array}", + "image_path": "5c3c8c24b4adfe4198c74c04f012f15fba7a9fc81c27203c3f6adc4805779083.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "spans": [ + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "inline_equation", + "content": "i \\in \\{1, 1 + N_p, \\dots, 1 + N - N_p\\}" + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "inline_equation", + "content": "j = i + N_p - 1" + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "text", + "content": ". Assuming that the grouped samples are lined on a ray, we use a single direction " + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "inline_equation", + "content": "\\mathbf{d}" + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "text", + "content": " in the input of " + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{MIMO}}" + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "text", + "content": ". In this formulation, the number of MLPs running to render a pixel (#Run) is equal to the number of groups and is calculated as #Run = " + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "inline_equation", + "content": "N / N_p" + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "text", + "content": ". Therefore, we can reduce the calculation cost, particularly that of #Run, by increasing " + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "inline_equation", + "content": "N_p" + }, + { + "bbox": [ + 305, + 135, + 545, + 219 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 220, + 545, + 290 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 220, + 545, + 290 + ], + "spans": [ + { + "bbox": [ + 304, + 220, + 545, + 290 + ], + "type": "text", + "content": "In inference, the only necessary modification to a NeRF is the simple replacement of " + }, + { + "bbox": [ + 304, + 220, + 545, + 290 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{SISO}}" + }, + { + "bbox": [ + 304, + 220, + 545, + 290 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 304, + 220, + 545, + 290 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{MIMO}}" + }, + { + "bbox": [ + 304, + 220, + 545, + 290 + ], + "type": "text", + "content": " and the same volume rendering (Equation 2) and sampling scheme (i.e., stratified and hierarchical sampling) can be used. With this modification strategy, MIMO-NeRF exhibits high compatibility and complementarity with previous NeRFs." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 290, + 545, + 375 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 290, + 545, + 375 + ], + "spans": [ + { + "bbox": [ + 304, + 290, + 545, + 375 + ], + "type": "text", + "content": "During training, " + }, + { + "bbox": [ + 304, + 290, + 545, + 375 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{pixel}}" + }, + { + "bbox": [ + 304, + 290, + 545, + 375 + ], + "type": "text", + "content": " (Equation 3) can be used for " + }, + { + "bbox": [ + 304, + 290, + 545, + 375 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{C}}" + }, + { + "bbox": [ + 304, + 290, + 545, + 375 + ], + "type": "text", + "content": " obtained using " + }, + { + "bbox": [ + 304, + 290, + 545, + 375 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{MIMO}}" + }, + { + "bbox": [ + 304, + 290, + 545, + 375 + ], + "type": "text", + "content": ". However, this loss does not necessarily suffice to address the ambiguity in the color and volume density of each point because this ambiguity occurs in a 3D space and the loss cannot regularize the 3D representations explicitly. Hence, we introduce self-supervised learning as discussed in subsequent sections." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 380, + 430, + 392 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 380, + 430, + 392 + ], + "spans": [ + { + "bbox": [ + 306, + 380, + 430, + 392 + ], + "type": "text", + "content": "4.2. MIMO reformulation" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 399, + 545, + 483 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 399, + 545, + 483 + ], + "spans": [ + { + "bbox": [ + 304, + 399, + 545, + 483 + ], + "type": "text", + "content": "One possible solution to this ambiguity is to train a standard (i.e., SISO) NeRF first and then distill the model onto a corresponding MIMO-NeRF. However, this solution involves an increase in training time because it requires training not only a MIMO-NeRF but also a SISO NeRF. Consequently, this solution cannot entirely take advantage of the fast rendering of MIMO-NeRF in training." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 483, + 545, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 483, + 545, + 613 + ], + "spans": [ + { + "bbox": [ + 304, + 483, + 545, + 613 + ], + "type": "text", + "content": "Alternatively, we reformulate a MIMO MLP in multiple ways and impose a consistent regularization to produce the same RGB colors and alpha values. Because each reformulated MIMO MLP can render a pixel faster than the original SISO MLP, we can prevent a large increase in training time even when using multiple reformulated MIMO MLPs by adequately adjusting the reformulation configuration. When implementing this idea, the question arises as to how best to reformulate a MIMO MLP. To this end, we developed two methods, including (1) group shift and (2) variation reduction." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 616, + 545, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 616, + 545, + 676 + ], + "spans": [ + { + "bbox": [ + 304, + 616, + 545, + 676 + ], + "type": "text", + "content": "Group shift. We consider restricting this ambiguity by assessing each point in multiple ways using different groups and imposing consistency on the assessed results. More formally, we implement this by shifting groups and rewriting Equation 4 as follows." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 314, + 681, + 545, + 711 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 314, + 681, + 545, + 711 + ], + "spans": [ + { + "bbox": [ + 314, + 681, + 545, + 711 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} f _ {\\mathrm {M I M O}} ^ {\\mathrm {s h i f t}}: (\\mathbb {R} ^ {3}) ^ {N _ {p}} \\times \\mathbb {S} ^ {2} \\to (\\mathbb {R} ^ {3} \\times \\mathbb {R} ^ {+}) ^ {N _ {p}}, \\\\ \\left(\\mathbf {x} _ {i ^ {\\prime}}, \\dots , \\mathbf {x} _ {j ^ {\\prime}}, \\mathbf {d}\\right) \\mapsto \\left(\\mathbf {c} _ {i ^ {\\prime}}, \\dots , \\mathbf {c} _ {j ^ {\\prime}}, \\sigma_ {i ^ {\\prime}}, \\dots , \\sigma_ {j ^ {\\prime}}\\right), \\tag {5} \\\\ \\end{array}", + "image_path": "87345ccd7ec48731c09bc75f70524b91ba9d98e91149d12e32bcc798a76a04b1.jpg" + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 46, + 673, + 287, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 673, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 673, + 287, + 713 + ], + "type": "text", + "content": "3One possible alternative is to group near samples on different rays. However, in NeRFs, searching near points across different rays is not trivial because points are sampled unevenly via hierarchical sampling. Therefore, we simply group neighboring samples on the same ray in this study." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3276" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 47, + 70, + 289, + 144 + ], + "blocks": [ + { + "bbox": [ + 47, + 70, + 289, + 144 + ], + "lines": [ + { + "bbox": [ + 47, + 70, + 289, + 144 + ], + "spans": [ + { + "bbox": [ + 47, + 70, + 289, + 144 + ], + "type": "image", + "image_path": "379aed44382020f4991b234dce1376b248d3a1ead134d95e989fb0597105b79b.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 154, + 288, + 199 + ], + "lines": [ + { + "bbox": [ + 46, + 154, + 288, + 199 + ], + "spans": [ + { + "bbox": [ + 46, + 154, + 288, + 199 + ], + "type": "text", + "content": "Figure 3. Example of the group shift when " + }, + { + "bbox": [ + 46, + 154, + 288, + 199 + ], + "type": "inline_equation", + "content": "N_{p} = 4" + }, + { + "bbox": [ + 46, + 154, + 288, + 199 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 154, + 288, + 199 + ], + "type": "inline_equation", + "content": "s = 2" + }, + { + "bbox": [ + 46, + 154, + 288, + 199 + ], + "type": "text", + "content": ". We shift each group by " + }, + { + "bbox": [ + 46, + 154, + 288, + 199 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 46, + 154, + 288, + 199 + ], + "type": "text", + "content": " toward the camera after padding " + }, + { + "bbox": [ + 46, + 154, + 288, + 199 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 46, + 154, + 288, + 199 + ], + "type": "text", + "content": " samples before the front sample. This procedure enables assessing each sample in multiple ways using different groups." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "spans": [ + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "inline_equation", + "content": "i' \\in \\{k, k + N_p, \\ldots, k + N\\}" + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "inline_equation", + "content": "j' = i' + N_p - 1" + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "text", + "content": ". Here, " + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "text", + "content": " is the head index of the first group, which is shifted by " + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "inline_equation", + "content": "s \\in \\{1, \\ldots, N_p - 1\\}" + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "text", + "content": " toward the camera. Hence, " + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "inline_equation", + "content": "k \\in \\{2 - N_p, \\ldots, 0\\}" + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "text", + "content": ". In practice, it is randomly sampled during training. More strictly, we add padding before this process to represent a sample with an index exceeding the original index, i.e., " + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "inline_equation", + "content": "i' < 1" + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "inline_equation", + "content": "j' > N" + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "text", + "content": ". For clarity, we present an example in which " + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "inline_equation", + "content": "N_p = 4" + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "inline_equation", + "content": "s = 2" + }, + { + "bbox": [ + 47, + 217, + 287, + 315 + ], + "type": "text", + "content": " in Figure 3." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 316, + 288, + 376 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 316, + 288, + 376 + ], + "spans": [ + { + "bbox": [ + 46, + 316, + 288, + 376 + ], + "type": "text", + "content": "Variation reduction. In the original MIMO formulation, the abovementioned ambiguity is caused by " + }, + { + "bbox": [ + 46, + 316, + 288, + 376 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 46, + 316, + 288, + 376 + ], + "type": "text", + "content": " different input samples. To mitigate this, we consider reducing the variation in the input by replacing Equation 4 with the following." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 56, + 384, + 219, + 399 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 384, + 219, + 399 + ], + "spans": [ + { + "bbox": [ + 56, + 384, + 219, + 399 + ], + "type": "interline_equation", + "content": "f _ {\\mathrm {M I M O}} ^ {\\text {r e d u c e}}: (\\mathbb {R} ^ {3}) ^ {N _ {p}} \\times \\mathbb {S} ^ {2} \\to (\\mathbb {R} ^ {3} \\times \\mathbb {R} ^ {+}) ^ {N _ {p}},", + "image_path": "249e51da3548620aa48f2931a445cdc1313dad0b90f19d484cc4eb036d63d35e.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 401, + 289, + 445 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 401, + 289, + 445 + ], + "spans": [ + { + "bbox": [ + 49, + 401, + 289, + 445 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\left(\\left[ \\mathbf {x} _ {i ^ {\\prime \\prime}} \\right] ^ {R}, \\ldots , \\left[ \\mathbf {x} _ {j ^ {\\prime \\prime}} \\right] ^ {R}, \\mathbf {d}\\right) \\mapsto \\left(\\mathbf {c} _ {i _ {1} ^ {\\prime \\prime}}, \\ldots , \\mathbf {c} _ {i _ {R} ^ {\\prime \\prime}}, \\ldots , \\mathbf {c} _ {j _ {1} ^ {\\prime \\prime}}, \\ldots , \\mathbf {c} _ {j _ {R} ^ {\\prime \\prime}}, \\right. \\\\ \\sigma_ {i _ {1} ^ {\\prime \\prime}}, \\dots , \\sigma_ {i _ {R} ^ {\\prime \\prime}}, \\dots , \\sigma_ {j _ {1} ^ {\\prime \\prime}}, \\dots , \\sigma_ {j _ {R} ^ {\\prime \\prime}}), \\tag {6} \\\\ \\end{array}", + "image_path": "44a65fa19d6d6b9500ca327e7522b16d3006a7b38a0ea01527a49e2cd7438648.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "spans": [ + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "[\\cdot ]^R" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": " denotes the operation of repeating the given variable " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "R" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": " times, " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "i''\\in \\{1,1 + \\frac{N_p}{R},\\ldots ,1 + N - \\frac{N_p}{R}\\}" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "j^{\\prime \\prime} = i^{\\prime \\prime} + \\frac{N_p}{R} -1" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": ". After applying " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{MIMO}}^{\\mathrm{reduce}}" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": ", we average " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "(\\mathbf{c}_{k_1^{\\prime \\prime}},\\dots,\\mathbf{c}_{k_R^{\\prime \\prime}})" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "(\\sigma_{k_1^{\\prime \\prime}},\\dots,\\sigma_{k_R^{\\prime \\prime}})" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": " to obtain " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "\\mathbf{c}_{k^{\\prime \\prime}}" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "\\sigma_{k^{\\prime \\prime}}" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "k^{\\prime \\prime}\\in \\{i^{\\prime \\prime},\\dots,j^{\\prime \\prime}\\}" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": ". In this formulation, the mentioned ambiguity is reduced by decreasing input variation from " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "\\frac{N_p}{R}" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": ". Conversely, the number of MLPs running increases by factor of " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "R" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": ", i.e., " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "\\# \\operatorname {Run} = N / N_p\\times R" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": "; therefore, we need to select " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "R" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": " carefully in practice to avoid a large increase in training time. For clarity, we present an example case in which " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "N_{p} = 4" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "inline_equation", + "content": "R = 2" + }, + { + "bbox": [ + 46, + 455, + 287, + 593 + ], + "type": "text", + "content": " in Figure 4." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 599, + 147, + 612 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 599, + 147, + 612 + ], + "spans": [ + { + "bbox": [ + 47, + 599, + 147, + 612 + ], + "type": "text", + "content": "4.3. MIMO objective" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "text", + "content": "Through the above processes, we obtain " + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "text", + "content": " reformulated MIMO MLPs in which we use different " + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "text", + "content": " for each MIMO MLP and set " + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "inline_equation", + "content": "R" + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "text", + "content": " such that the total number of # Run is not larger than that of the original SISO MLP. Hereafter, we use the superscript " + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "inline_equation", + "content": "m \\in \\{1, \\dots, M\\}" + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "text", + "content": " to denote the variable corresponding to the " + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "text", + "content": "-th reformulated MIMO MLP, e.g., " + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{C}}^m" + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "inline_equation", + "content": "R^m" + }, + { + "bbox": [ + 46, + 617, + 288, + 715 + ], + "type": "text", + "content": ". We train these MLPs using two loss functions, including pixel-wise and 3D consistency losses." + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 353, + 68, + 500, + 137 + ], + "blocks": [ + { + "bbox": [ + 353, + 68, + 500, + 137 + ], + "lines": [ + { + "bbox": [ + 353, + 68, + 500, + 137 + ], + "spans": [ + { + "bbox": [ + 353, + 68, + 500, + 137 + ], + "type": "image", + "image_path": "c887b051e676ac30bc781ef5cfb2f4ef8250c929a58630e1cd808f8722c54e7c.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "lines": [ + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "spans": [ + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "text", + "content": "Figure 4. Example of variation reduction when " + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "inline_equation", + "content": "N_{p} = 4" + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "inline_equation", + "content": "R = 2" + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "text", + "content": ". Samples with the same color correspond to the same coordinate. In " + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{MIMO}}^{\\mathrm{reduce}}" + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "text", + "content": ", we reduce the number of unique samples in a group from " + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "inline_equation", + "content": "N_{p} (= 4)" + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "inline_equation", + "content": "\\frac{N_{p}}{R} (= 2)" + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "text", + "content": " by repeating each sample " + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "inline_equation", + "content": "R (= 2)" + }, + { + "bbox": [ + 305, + 147, + 547, + 202 + ], + "type": "text", + "content": " times to reduce the variation in a group." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 221, + 545, + 244 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 221, + 545, + 244 + ], + "spans": [ + { + "bbox": [ + 305, + 221, + 545, + 244 + ], + "type": "text", + "content": "Pixel-wise loss. We apply the pixel-wise loss (Equation 3) to each " + }, + { + "bbox": [ + 305, + 221, + 545, + 244 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{C}}^m" + }, + { + "bbox": [ + 305, + 221, + 545, + 244 + ], + "type": "text", + "content": " as follows." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 367, + 251, + 545, + 283 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 367, + 251, + 545, + 283 + ], + "spans": [ + { + "bbox": [ + 367, + 251, + 545, + 283 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {p i x e l}} ^ {\\mathrm {M I M O}} = \\sum_ {m = 1} ^ {M} \\| \\hat {\\mathbf {C}} ^ {m} - \\mathbf {C} \\| _ {2} ^ {2}. \\tag {7}", + "image_path": "07769e55f1883ee3dabd08e1652d3fe6876f614ea010f49a17a1763f0ae53ae9.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 293, + 545, + 392 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 293, + 545, + 392 + ], + "spans": [ + { + "bbox": [ + 305, + 293, + 545, + 392 + ], + "type": "text", + "content": "3D consistency loss. The pixel-wise loss provides supervision in a 2D space; however, it cannot impose an explicit regularization in a 3D space. Hence, we introduce a 3D consistency loss that encourages the reformulated MIMO MLPs to produce the same colors and alpha values in the 3D space. The 3D consistency loss consists of a color 3D consistency loss " + }, + { + "bbox": [ + 305, + 293, + 545, + 392 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{3D}}^{\\mathrm{color}}" + }, + { + "bbox": [ + 305, + 293, + 545, + 392 + ], + "type": "text", + "content": " and an alpha value 3D consistency loss " + }, + { + "bbox": [ + 305, + 293, + 545, + 392 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{3D}}^{\\mathrm{alpha}}" + }, + { + "bbox": [ + 305, + 293, + 545, + 392 + ], + "type": "text", + "content": " as follows." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 315, + 399, + 545, + 460 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 399, + 545, + 460 + ], + "spans": [ + { + "bbox": [ + 315, + 399, + 545, + 460 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {L} _ {\\mathrm {3 D}} ^ {\\mathrm {c o l o r}} = \\sum_ {m _ {1} = 1} ^ {M - 1} \\sum_ {m _ {2} = m _ {1} + 1} ^ {M} \\frac {1}{N} \\sum_ {i = 1} ^ {N} \\left[ \\mu_ {m _ {1}} ^ {m _ {2}} \\| \\mathbf {c} _ {i} ^ {m _ {1}} - \\operatorname {s g} \\left(\\mathbf {c} _ {i} ^ {m _ {2}}\\right) \\| _ {2} ^ {2} \\right. \\\\ + \\mu_ {m _ {2}} ^ {m _ {1}} \\| \\operatorname {s g} \\left(\\mathbf {c} _ {i} ^ {m _ {1}}\\right) - \\mathbf {c} _ {i} ^ {m _ {2}} \\| _ {2} ^ {2} ], \\tag {8} \\\\ \\end{array}", + "image_path": "c0e313bb42001b8d67b64a47337a840b827b5b891ca9eb7558e3af289c76cbbd.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 312, + 463, + 545, + 524 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 463, + 545, + 524 + ], + "spans": [ + { + "bbox": [ + 312, + 463, + 545, + 524 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {L} _ {\\mathrm {3 D}} ^ {\\mathrm {a l p h a}} = \\sum_ {m _ {1} = 1} ^ {M - 1} \\sum_ {m _ {2} = m _ {1} + 1} ^ {M} \\frac {1}{N} \\sum_ {i = 1} ^ {N} \\left[ \\mu_ {m _ {1}} ^ {m _ {2}} \\| \\alpha_ {i} ^ {m _ {1}} - \\operatorname {s g} \\left(\\alpha_ {i} ^ {m _ {2}}\\right) \\| _ {2} ^ {2} \\right. \\\\ + \\mu_ {m _ {2}} ^ {m _ {1}} \\| \\operatorname {s g} \\left(\\alpha_ {i} ^ {m _ {1}}\\right) - \\alpha_ {i} ^ {m _ {2}} \\| _ {2} ^ {2} ]. \\tag {9} \\\\ \\end{array}", + "image_path": "649ffd01cb345c954cd484899d1fcd1e6213dd3b2778b878405a9d93794025a9.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "spans": [ + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "content": "where \"sg\" indicate a stop-gradient operation. The 3D consistency loss " + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{3D}}" + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "content": " is calculated by " + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{3D}} = \\mathcal{L}_{\\mathrm{3D}}^{\\mathrm{color}} + \\mathcal{L}_{\\mathrm{3D}}^{\\mathrm{alpha}}" + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "content": ". We define " + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "inline_equation", + "content": "\\mu_{m_i}^{m_j}" + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "inline_equation", + "content": "\\mu_{m_i}^{m_j} = \\frac{\\sqrt{R^{m_j}}}{\\sqrt{R^{\\max} \\sqrt{R^{m_i}}}}" + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "inline_equation", + "content": "R^{\\max}" + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "content": " is the maximum of " + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "inline_equation", + "content": "R^{m}" + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "content": " in " + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "inline_equation", + "content": "m \\in \\{1, \\ldots, M\\}" + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "content": ". We use this asymmetric weight on the assumption that " + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "inline_equation", + "content": "\\mathbf{c}_i^m" + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "inline_equation", + "content": "\\alpha_i^m" + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "content": " with greater " + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "inline_equation", + "content": "R^{m}" + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "content": " have lower ambiguity and are more reliable. Hence, the effect of " + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{3D}}" + }, + { + "bbox": [ + 305, + 533, + 545, + 644 + ], + "type": "text", + "content": " is reduced. We empirically investigated the importance of this effect through an ablation study as described in Section 5.3." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 647, + 524, + 659 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 647, + 524, + 659 + ], + "spans": [ + { + "bbox": [ + 306, + 647, + 524, + 659 + ], + "type": "text", + "content": "Full objective. The full objective is defined as follows." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 372, + 666, + 545, + 682 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 372, + 666, + 545, + 682 + ], + "spans": [ + { + "bbox": [ + 372, + 666, + 545, + 682 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {M I M O}} = \\mathcal {L} _ {\\text {p i x e l}} ^ {\\mathrm {M I M O}} + \\lambda \\mathcal {L} _ {\\mathrm {3 D}}, \\tag {10}", + "image_path": "63185d71b0ad7906b4adc97c4352fb6b79419edcd31125cbb39bb934cbd7d28d.jpg" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "content": " is a hyperparameter that balances the pixel-wise loss and 3D consistency loss." + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3277" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 71, + 128, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 71, + 128, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 71, + 128, + 85 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 91, + 289, + 259 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 91, + 289, + 259 + ], + "spans": [ + { + "bbox": [ + 46, + 91, + 289, + 259 + ], + "type": "text", + "content": "We conducted five experiments to investigate the effectiveness of MIMO-NeRF. In the first three experiments, we conducted a comprehensive study, including an investigation of benchmark performance (Section 5.1), an investigation of the trade-off between speed and quality (Section 5.2), and ablation studies (Section 5.3). In the remaining two experiments, we examined the versatility of MIMO-NeRF by applying it to two representative fast NeRFs, including a NeRF with a sampling network, i.e., DONeRF [41] (Section 5.4), and a NeRF with alternative representations, i.e., TensoRF [9] (Section 5.5). The main results of these experiments are provided here, and detailed analyses are presented with extended results in Appendix A. The implementation details are presented in Appendix B." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 267, + 261, + 280 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 267, + 261, + 280 + ], + "spans": [ + { + "bbox": [ + 47, + 267, + 261, + 280 + ], + "type": "text", + "content": "5.1. Investigation of benchmark performance" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 286, + 287, + 443 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 286, + 287, + 443 + ], + "spans": [ + { + "bbox": [ + 46, + 286, + 287, + 443 + ], + "type": "text", + "content": "First, we investigated the benchmark performance of MIMO-NeRF by applying our ideas to the original NeRF [39]. In particular, we examined three variants of MIMO-NeRF, including MIMO-NeRF-naive, which simply replaced " + }, + { + "bbox": [ + 46, + 286, + 287, + 443 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{SISO}}" + }, + { + "bbox": [ + 46, + 286, + 287, + 443 + ], + "type": "text", + "content": " (Equation 1) with " + }, + { + "bbox": [ + 46, + 286, + 287, + 443 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{MIMO}}" + }, + { + "bbox": [ + 46, + 286, + 287, + 443 + ], + "type": "text", + "content": " (Equation 4) and was trained with a standard pixel-wise loss (Equation 3). MIMO-NeRF-distill, which is a student model distilled from a pretrained standard (i.e., SISO) NeRF. During training, we used a 3D consistency loss (Equations 8 and 9) that was adjusted for knowledge distillation, in addition to the pixelwise loss. MIMO-NeRF-self, which is MIMO-NeRF that adopted the proposed self-supervised learning. We examined the performance when " + }, + { + "bbox": [ + 46, + 286, + 287, + 443 + ], + "type": "inline_equation", + "content": "N_p" + }, + { + "bbox": [ + 46, + 286, + 287, + 443 + ], + "type": "text", + "content": " was varied within " + }, + { + "bbox": [ + 46, + 286, + 287, + 443 + ], + "type": "inline_equation", + "content": "\\{2,4,8\\}" + }, + { + "bbox": [ + 46, + 286, + 287, + 443 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 445, + 288, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 445, + 288, + 601 + ], + "spans": [ + { + "bbox": [ + 46, + 445, + 288, + 601 + ], + "type": "text", + "content": "Datasets. We investigated the benchmark performance on two commonly-used datasets. (1) Blender dataset [39] includes eight scenes, each of which consists of " + }, + { + "bbox": [ + 46, + 445, + 288, + 601 + ], + "type": "inline_equation", + "content": "360^{\\circ}" + }, + { + "bbox": [ + 46, + 445, + 288, + 601 + ], + "type": "text", + "content": " views of complex objects at a resolution of " + }, + { + "bbox": [ + 46, + 445, + 288, + 601 + ], + "type": "inline_equation", + "content": "800 \\times 800" + }, + { + "bbox": [ + 46, + 445, + 288, + 601 + ], + "type": "text", + "content": " pixels. We used 100 and 200 views for training and testing, respectively. (2) Local Light Field Fusion (LLFF) dataset [38, 39], which consists of eight complex real-world scenes, each of which includes 20-62 forward-facing views at " + }, + { + "bbox": [ + 46, + 445, + 288, + 601 + ], + "type": "inline_equation", + "content": "1008 \\times 756" + }, + { + "bbox": [ + 46, + 445, + 288, + 601 + ], + "type": "text", + "content": " pixels. One-eighth of the images were used for testing, and the remainder were used for training. Where not otherwise specified, we used half-sized images following the default settings of a widely-used source code for " + }, + { + "bbox": [ + 46, + 445, + 288, + 601 + ], + "type": "inline_equation", + "content": "\\mathrm{NeRF}^5" + }, + { + "bbox": [ + 46, + 445, + 288, + 601 + ], + "type": "text", + "content": " to better investigate the various configurations." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 604, + 288, + 666 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 604, + 288, + 666 + ], + "spans": [ + { + "bbox": [ + 47, + 604, + 288, + 666 + ], + "type": "text", + "content": "Implementation. For a fair comparison, we implemented all the models with a commonly-used source code for " + }, + { + "bbox": [ + 47, + 604, + 288, + 666 + ], + "type": "inline_equation", + "content": "\\mathrm{NeRF}^5" + }, + { + "bbox": [ + 47, + 604, + 288, + 666 + ], + "type": "text", + "content": " and trained the models using the default settings provided in the code. The number of samples was set as " + }, + { + "bbox": [ + 47, + 604, + 288, + 666 + ], + "type": "inline_equation", + "content": "N_{c} = 64" + }, + { + "bbox": [ + 47, + 604, + 288, + 666 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 604, + 288, + 666 + ], + "type": "inline_equation", + "content": "N_{f} = 128" + }, + { + "bbox": [ + 47, + 604, + 288, + 666 + ], + "type": "text", + "content": " for the Blender dataset and" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "N_{c} = 64" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "N_{f} = 64" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": " for the LLFF dataset. For MIMO-NeRF-self, we used two formulations with " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "R^{1} = R^{2} = 1" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": " when " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "N_{p} = 2" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": ", two formulations with " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "R^{1} = 1" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "R^{2} = 2" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": " when " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "N_{p} = 4" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": ", and three formulations with " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "R^{1} = 1" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "R^{2} = 2" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "R^{3} = 4" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": " when " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "N_{p} = 8" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": ". MIMO-NeRF-self was trained individually depending on " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": ". An investigation of different reformulation methods is presented in Appendix A.2. Group shifts were applied to all cases. We set " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": " to 1 and 0.4 for the Blender and LLFF datasets, respectively. The effect of " + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 306, + 72, + 545, + 205 + ], + "type": "text", + "content": " is analyzed in Appendix A.3. The implementation details are presented in Appendix B.1." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 207, + 546, + 380 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 207, + 546, + 380 + ], + "spans": [ + { + "bbox": [ + 304, + 207, + 546, + 380 + ], + "type": "text", + "content": "Evaluation metrics. Following the original NeRF study [39], we used the peak signal-to-noise ratio (PSNR), structural similarity index (SSIM) [64], and learned perceptual image patch similarity (LPIPS) [73] to quantitatively evaluate the image quality. To assess the calculation cost of inference and training, we report inference time (I-time) measured with an NVIDIA GeForce RTX 3080 Ti GPU and training time (T-time) measured with an NVIDIA A100-SXM4-80GB GPU. We also provide # Run " + }, + { + "bbox": [ + 304, + 207, + 546, + 380 + ], + "type": "inline_equation", + "content": "\\left(= \\frac{N_c + (N_c + N_f)}{N_p}\\right)" + }, + { + "bbox": [ + 304, + 207, + 546, + 380 + ], + "type": "text", + "content": " and the number of parameters (# Params) as supplementary information. # Params increases in MIMO-NeRF mainly because the total dimension of the positional embeddings is increased by " + }, + { + "bbox": [ + 304, + 207, + 546, + 380 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 304, + 207, + 546, + 380 + ], + "type": "text", + "content": " times according to the increase in the inputs." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 382, + 507, + 394 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 382, + 507, + 394 + ], + "spans": [ + { + "bbox": [ + 306, + 382, + 507, + 394 + ], + "type": "text", + "content": "Results. From Table 1, the following is observed." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 397, + 545, + 553 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 397, + 545, + 553 + ], + "spans": [ + { + "bbox": [ + 304, + 397, + 545, + 553 + ], + "type": "text", + "content": "Image quality. MIMO-NeRF-self outperformed not only MIMO-NeRF-naive but also MIMO-NeRF-distill in most cases in terms of PSNR, SSIM, and LPIPS. We conjecture that this occurred because the joint optimization of the teacher and student networks in MIMO-NeRF-self was more effective for training than the student-only optimization in MIMO-NeRF-distill. Even MIMO-NeRF-self suffered from a trade-off between speed and quality with increasing " + }, + { + "bbox": [ + 304, + 397, + 545, + 553 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 304, + 397, + 545, + 553 + ], + "type": "text", + "content": "; however, MIMO-NeRF-self performed better than or comparably to the original NeRF when " + }, + { + "bbox": [ + 304, + 397, + 545, + 553 + ], + "type": "inline_equation", + "content": "N_{p} = 2" + }, + { + "bbox": [ + 304, + 397, + 545, + 553 + ], + "type": "text", + "content": ". This may have occurred because the advantage of accumulating neighboring information and the disadvantage of handling the ambiguity were antagonistic in this case." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 555, + 547, + 593 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 555, + 547, + 593 + ], + "spans": [ + { + "bbox": [ + 304, + 555, + 547, + 593 + ], + "type": "text", + "content": "Inference speed. All MIMO-NeRFs with the same inference procedure showed inference times improved by a factor of 1.84–5.78 with increasing " + }, + { + "bbox": [ + 304, + 555, + 547, + 593 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 304, + 555, + 547, + 593 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 594, + 547, + 667 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 547, + 667 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 547, + 667 + ], + "type": "text", + "content": "Training speed. MIMO-NeRF-naive achieved the fastest training because it used only a single MIMO formulation during training. MIMO-NeRF-self required more training time because it uses multiple MIMO reformulations; however, each calculation cost is low. Therefore, it did not suffer from a large increase in training time compared" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 46, + 673, + 286, + 702 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 673, + 286, + 702 + ], + "spans": [ + { + "bbox": [ + 46, + 673, + 286, + 702 + ], + "type": "text", + "content": "4For simplicity and a fair comparison, we only increased the input and output of the original SISO MLP and retained the other parameters (e.g., depth and width). Hence, the increase in model size was relatively small." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 58, + 703, + 266, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 703, + 266, + 713 + ], + "spans": [ + { + "bbox": [ + 58, + 703, + 266, + 713 + ], + "type": "text", + "content": "5https://github.com/yenchenlin/nerf-pytorch" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 673, + 545, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 673, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 673, + 545, + 713 + ], + "type": "text", + "content": "For simplicity and a fair comparison, we measured the calculation time using a standard PyTorch implementation for all the models. Optimizing the implementation for faster rendering (e.g., using custom CUDA kernels) would be interesting for future research." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3278" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 47, + 69, + 547, + 178 + ], + "blocks": [ + { + "bbox": [ + 47, + 69, + 547, + 178 + ], + "lines": [ + { + "bbox": [ + 47, + 69, + 547, + 178 + ], + "spans": [ + { + "bbox": [ + 47, + 69, + 547, + 178 + ], + "type": "table", + "html": "
ModelNpPSNR↑SSIM↑LPIPS↓Blender # Run↓I-time↓ (s)T-time↓ (h)# Params (M)PSNR↑SSIM↑LPIPS↓LLFF # Run↓I-time↓ (s)T-time↓ (h)# Params (M)
NeRF131.040.9510.0552569.604.701.1927.720.8710.1501928.383.391.19
MIMO-NeRF-naive30.180.9440.0651285.153.091.2627.310.8600.167964.552.121.26
MIMO-NeRF-distill 2230.760.9490.0581285.159.461.2627.500.8630.169964.556.811.26
MIMO-NeRF-self331.260.9530.0541285.155.361.2627.700.8700.155964.553.971.26
MIMO-NeRF-naive28.620.9270.091642.792.021.3926.290.8240.218482.461.571.39
MIMO-NeRF-distill 4430.220.9460.065642.798.421.3927.370.8610.172482.466.251.39
MIMO-NeRF-self330.940.9500.058642.794.681.3927.510.8650.162482.463.441.39
MIMO-NeRF-naive26.340.8950.133321.661.661.6525.100.7740.284241.451.241.65
MIMO-NeRF-distill 8829.390.9370.075321.668.071.6527.010.8510.184241.455.911.65
MIMO-NeRF-self330.400.9450.065321.665.861.6526.970.8510.180241.454.431.65
", + "image_path": "6d6c94c144d5f5da210a7c7d082581d3aa3a90c55a2c1bb0f8ddfda4e4251a4c.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 185, + 547, + 220 + ], + "lines": [ + { + "bbox": [ + 46, + 185, + 547, + 220 + ], + "spans": [ + { + "bbox": [ + 46, + 185, + 547, + 220 + ], + "type": "text", + "content": "Table 1. Benchmark performance of MIMO-NeRFs. MIMO-NeRF-self outperformed MIMO-NeRF-naive and MIMO-NeRF-distill in terms of PSNR, SSIM, and LPIPS in most cases with shorter training time than MIMO-NeRF-distill. All MIMO-NeRFs outperformed the original NeRF in terms of inference time owing to the reduction of # Run." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "type": "image", + "bbox": [ + 47, + 236, + 289, + 388 + ], + "blocks": [ + { + "bbox": [ + 47, + 236, + 289, + 388 + ], + "lines": [ + { + "bbox": [ + 47, + 236, + 289, + 388 + ], + "spans": [ + { + "bbox": [ + 47, + 236, + 289, + 388 + ], + "type": "image", + "image_path": "21677546a92471a00f99cbfe2616dfc1981e5c46a2b0b6e3d65410077252142c.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 399, + 288, + 477 + ], + "lines": [ + { + "bbox": [ + 46, + 399, + 288, + 477 + ], + "spans": [ + { + "bbox": [ + 46, + 399, + 288, + 477 + ], + "type": "text", + "content": "Figure 5. Qualitative comparison between NeRF and MIMO-NeRFs with " + }, + { + "bbox": [ + 46, + 399, + 288, + 477 + ], + "type": "inline_equation", + "content": "N_{p} = 8" + }, + { + "bbox": [ + 46, + 399, + 288, + 477 + ], + "type": "text", + "content": ". The models were trained using full-sized images. MIMO-NeRF-naive (c) produced some artifacts owing to the ambiguity in the color and volume density of each point. MIMO-NeRF-self (d) was useful for addressing this issue, and its results were close to those of NeRF (b), while inference time were improved by a factor of 5.8." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 511, + 287, + 535 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 511, + 287, + 535 + ], + "spans": [ + { + "bbox": [ + 46, + 511, + 287, + 535 + ], + "type": "text", + "content": "with MIMO-NeRF-distill, which requires training not only a MIMO-NeRF but also a SISO NeRF." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "spans": [ + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "text", + "content": "Summary. From these results, we found that when " + }, + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "inline_equation", + "content": "N_{p} = 2" + }, + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "text", + "content": ", MIMO-NeRF-self improved the inference speed of NeRF without compromising image quality, and when " + }, + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "text", + "content": " was larger, there was a trade-off between speed and quality. We examine the validity of this trade-off in Section 5.2." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "content": "Qualitative results. Figure 5 shows a qualitative comparison between NeRF, MIMO-NeRF-naive, and MIMO-NeRF-self. In this experiment, we used full-sized images to train the models and set " + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "content": " to 8 for MIMO-NeRFs. MIMO-NeRF-naive produced some artifacts, whereas MIMO-NeRF-self adequately addressed this issue. The additional results are provided in Appendix A.6." + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 306, + 236, + 421, + 331 + ], + "blocks": [ + { + "bbox": [ + 306, + 236, + 421, + 331 + ], + "lines": [ + { + "bbox": [ + 306, + 236, + 421, + 331 + ], + "spans": [ + { + "bbox": [ + 306, + 236, + 421, + 331 + ], + "type": "image", + "image_path": "343e964da66cab51a41ba04f942d480e4286c6b42985dec995480b1c98310310.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 343, + 547, + 389 + ], + "lines": [ + { + "bbox": [ + 304, + 343, + 547, + 389 + ], + "spans": [ + { + "bbox": [ + 304, + 343, + 547, + 389 + ], + "type": "text", + "content": "Figure 6. Relationship between FLOPs and PSNR. Higher values indicate better the image quality. Faster speeds are shown to the left. MIMO-NeRF-self achieves the best trade-off between speed and quality." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 430, + 236, + 547, + 332 + ], + "blocks": [ + { + "bbox": [ + 430, + 236, + 547, + 332 + ], + "lines": [ + { + "bbox": [ + 430, + 236, + 547, + 332 + ], + "spans": [ + { + "bbox": [ + 430, + 236, + 547, + 332 + ], + "type": "image", + "image_path": "707968fd4b819dc01b68f13bf8c8572ee630f047ae633a78e3147bb88d7c07b8.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 407, + 512, + 421 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 407, + 512, + 421 + ], + "spans": [ + { + "bbox": [ + 306, + 407, + 512, + 421 + ], + "type": "text", + "content": "5.2. Investigation of speed-quality trade-off" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 426, + 547, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 426, + 547, + 533 + ], + "spans": [ + { + "bbox": [ + 304, + 426, + 547, + 533 + ], + "type": "text", + "content": "We compared MIMO-NeRF with possible alternatives to investigate whether it achieved a good trade-off between speed and quality. In particular, we focused on methods that are general and applicable to various NeRFs, similar to MIMO-NeRF, and examined two variants, including NeRF-few, which reduced the number of samples on a ray, and NeRF-small, which reduced the number of features in the hidden layers. We adjusted the parameters such that their FLOPs were comparable to those of MIMO-NeRF.7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 536, + 547, + 609 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 536, + 547, + 609 + ], + "spans": [ + { + "bbox": [ + 304, + 536, + 547, + 609 + ], + "type": "text", + "content": "Results. The relationship between the FLOPs and PSNR is plotted in Figure 6. We found that MIMO-NeRF-self obtained a better trade-off between speed and quality than NeRF-few and NeRF-small. We provide other relationships (e.g., relationships between FLOPs/inference time and PSNR/SSIM/LPIPS) in Appendix A.4." + }, + { + "bbox": [ + 304, + 536, + 547, + 609 + ], + "type": "inline_equation", + "content": "^{8}" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 304, + 616, + 545, + 666 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 616, + 545, + 666 + ], + "spans": [ + { + "bbox": [ + 304, + 616, + 545, + 666 + ], + "type": "text", + "content": "7We tuned the models based on FLOPs because the performance of different methods for improving speed in terms of inference time may vary depending on the calculation tools used, such as GPU processor hardware. As a reference, we provide the relationship between the inference time and image quality in Appendix A.4." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "text", + "content": "8During training, the calculation cost of MIMO-NeRF-self was larger than those of NeRF-small and NeRF-few because multiple MIMO reformulations were used. To confirm this effect, we examined the performance of NeRF-few and NeRF-small with increasing batch sizes such that the calculation costs became almost the same as that of MIMO-NeRF-self. We" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3279" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 69, + 289, + 178 + ], + "blocks": [ + { + "bbox": [ + 48, + 69, + 289, + 178 + ], + "lines": [ + { + "bbox": [ + 48, + 69, + 289, + 178 + ], + "spans": [ + { + "bbox": [ + 48, + 69, + 289, + 178 + ], + "type": "table", + "html": "
\\(N_p\\)GSCLAWBlenderLLFF
PSNR↑SSIM↑LPIPS↓PSNR↑SSIM↑LPIPS↓
2✓30.170.9430.06727.210.8560.170
✓30.540.9450.06527.480.8650.161
✓✓31.260.9530.05427.700.8700.155
4✓✓30.840.9490.05827.390.8620.166
✓29.480.9360.07726.460.8320.206
✓✓30.870.9490.06027.440.8640.164
✓✓✓30.940.9500.05827.510.8650.162
8✓✓29.810.9410.06926.970.8510.179
✓27.390.9070.11624.290.7340.332
✓✓30.160.9420.07126.690.8430.192
✓✓✓30.400.9450.06526.970.8510.180
", + "image_path": "fbe9a35d9858ddad96b45bf09ae13fb70b3c98acc91d37f161cceddcf0664026.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 248, + 145, + 260 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 248, + 145, + 260 + ], + "spans": [ + { + "bbox": [ + 47, + 248, + 145, + 260 + ], + "type": "text", + "content": "5.3. Ablation studies" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 267, + 287, + 339 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 267, + 287, + 339 + ], + "spans": [ + { + "bbox": [ + 47, + 267, + 287, + 339 + ], + "type": "text", + "content": "We also conducted ablation studies to better understand the performance of each element of the proposed self-supervised learning method. Specifically, we investigated the importance of group shift, 3D consistency loss, and asymmetric weights. When asymmetric weights were ablated, " + }, + { + "bbox": [ + 47, + 267, + 287, + 339 + ], + "type": "inline_equation", + "content": "\\mu_{m_i}^{m_j}" + }, + { + "bbox": [ + 47, + 267, + 287, + 339 + ], + "type": "text", + "content": " was set to 1." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 342, + 287, + 379 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 342, + 287, + 379 + ], + "spans": [ + { + "bbox": [ + 47, + 342, + 287, + 379 + ], + "type": "text", + "content": "Results. The results are listed in Table 2. We found that the full model achieved the best performance in most cases. The results validate the importance of each technique." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 387, + 182, + 400 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 387, + 182, + 400 + ], + "spans": [ + { + "bbox": [ + 47, + 387, + 182, + 400 + ], + "type": "text", + "content": "5.4. Application to DONeRF" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 406, + 287, + 525 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 406, + 287, + 525 + ], + "spans": [ + { + "bbox": [ + 46, + 406, + 287, + 525 + ], + "type": "text", + "content": "We incorporated MIMO-NeRF into DONeRF [41], a representative NeRF with a sampling network, to demonstrate that MIMO-NeRF can complement existing fast NeRFs. DONeRF uses a sampling network called a depth oracle network to select samples and calculates the colors and volume densities of the selected samples using a shading network. It handles the trade-off between speed and image quality by adjusting the number of selected samples " + }, + { + "bbox": [ + 46, + 406, + 287, + 525 + ], + "type": "inline_equation", + "content": "(N_{s})" + }, + { + "bbox": [ + 46, + 406, + 287, + 525 + ], + "type": "text", + "content": ". We examined whether MIMO-NeRF could be used as an alternative to handle this trade-off." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 530, + 287, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 530, + 287, + 601 + ], + "spans": [ + { + "bbox": [ + 46, + 530, + 287, + 601 + ], + "type": "text", + "content": "Datasets. We evaluated the performance using the DONeRF dataset [41] comprising six synthetic indoor and outdoor scenes. Each scene included 300 forward-facing views at a resolution of " + }, + { + "bbox": [ + 46, + 530, + 287, + 601 + ], + "type": "inline_equation", + "content": "800 \\times 800" + }, + { + "bbox": [ + 46, + 530, + 287, + 601 + ], + "type": "text", + "content": " pixels. " + }, + { + "bbox": [ + 46, + 530, + 287, + 601 + ], + "type": "inline_equation", + "content": "70\\%" + }, + { + "bbox": [ + 46, + 530, + 287, + 601 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 530, + 287, + 601 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 46, + 530, + 287, + 601 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 530, + 287, + 601 + ], + "type": "inline_equation", + "content": "20\\%" + }, + { + "bbox": [ + 46, + 530, + 287, + 601 + ], + "type": "text", + "content": " of the images were used for training, validation, and testing, respectively." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 605, + 287, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 287, + 665 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 287, + 665 + ], + "type": "text", + "content": "Implementation. We implemented the models according to the source code of DONeRF and trained them using the default settings. We applied MIMO-NeRF with " + }, + { + "bbox": [ + 46, + 605, + 287, + 665 + ], + "type": "inline_equation", + "content": "N_{p} = 4" + }, + { + "bbox": [ + 46, + 605, + 287, + 665 + ], + "type": "text", + "content": " to DONeRF-16 (i.e., DONeRF with " + }, + { + "bbox": [ + 46, + 605, + 287, + 665 + ], + "type": "inline_equation", + "content": "N_{s} = 16" + }, + { + "bbox": [ + 46, + 605, + 287, + 665 + ], + "type": "text", + "content": "). In the self-supervised learning process, we used two formulations with" + } + ] + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 306, + 69, + 545, + 121 + ], + "blocks": [ + { + "bbox": [ + 47, + 185, + 287, + 228 + ], + "lines": [ + { + "bbox": [ + 47, + 185, + 287, + 228 + ], + "spans": [ + { + "bbox": [ + 47, + 185, + 287, + 228 + ], + "type": "text", + "content": "Table 2. Results of ablation studies. Check marks in GS, CL, and AW indicate the use of group shift, 3D consistency loss, and asymmetric weights. In " + }, + { + "bbox": [ + 47, + 185, + 287, + 228 + ], + "type": "inline_equation", + "content": "N_{p} = 2" + }, + { + "bbox": [ + 47, + 185, + 287, + 228 + ], + "type": "text", + "content": ", asymmetric weights were not used in the full model because " + }, + { + "bbox": [ + 47, + 185, + 287, + 228 + ], + "type": "inline_equation", + "content": "R^{1} = R^{2} = 1" + }, + { + "bbox": [ + 47, + 185, + 287, + 228 + ], + "type": "text", + "content": ". Hence, it was not ablated." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 306, + 69, + 545, + 121 + ], + "lines": [ + { + "bbox": [ + 306, + 69, + 545, + 121 + ], + "spans": [ + { + "bbox": [ + 306, + 69, + 545, + 121 + ], + "type": "table", + "html": "
ModelPSNR↑FLIP↓# Run↓I-time↓(s)T-time↓(h)# Params(M)
DONeRF-1633.060.061170.4293.790.94
DONeRF-431.210.07050.1403.230.94
MIMO-DONeRF-16/4-naive32.300.06350.1553.260.99
MIMO-DONeRF-16/4-self32.720.06150.1553.560.99
", + "image_path": "0136e3bc692d9ff2194fc9bb9946f0104451ffe28614b64e8cc58262ecba94b4.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 129, + 545, + 194 + ], + "lines": [ + { + "bbox": [ + 305, + 129, + 545, + 194 + ], + "spans": [ + { + "bbox": [ + 305, + 129, + 545, + 194 + ], + "type": "text", + "content": "Table 3. Comparison of quantitative scores between DONeRFs and MIMO-DONeRFs. MIMO-DONeRF-16/4-naive outperformed DONeRF-4 in terms of PSNR and FLIP with a small increase in I-time and T-time. The performance of MIMO-DONeRF-16/4-self was close to DONeRF-16 in terms of PSNR and FLIP with shorter I-time and T-time." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 305, + 213, + 545, + 275 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 213, + 545, + 275 + ], + "spans": [ + { + "bbox": [ + 305, + 213, + 545, + 275 + ], + "type": "inline_equation", + "content": "R^1 = R^2 = 1" + }, + { + "bbox": [ + 305, + 213, + 545, + 275 + ], + "type": "text", + "content": " and group shifts. This model is referred to as MIMO-DonNeRF-16/4. We set " + }, + { + "bbox": [ + 305, + 213, + 545, + 275 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 305, + 213, + 545, + 275 + ], + "type": "text", + "content": " to 0.001. As a baseline, we examined DONeRF-4, which had the same # Run as MIMO-DonNeRF-16/4. The implementation details are presented in Appendix B.2." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 278, + 545, + 342 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 278, + 545, + 342 + ], + "spans": [ + { + "bbox": [ + 305, + 278, + 545, + 342 + ], + "type": "text", + "content": "Evaluation metrics. Following the study on DONeRF [41], we assessed the image quality using the PSNR and FLIP [1]. In addition, we used the # Run, I-time, T-time, and # Params described in Section 5.1. In DONeRF, # Run was calculated as " + }, + { + "bbox": [ + 305, + 278, + 545, + 342 + ], + "type": "inline_equation", + "content": "1 + \\frac{N_s}{N_p}" + }, + { + "bbox": [ + 305, + 278, + 545, + 342 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 344, + 545, + 488 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 344, + 545, + 488 + ], + "spans": [ + { + "bbox": [ + 305, + 344, + 545, + 488 + ], + "type": "text", + "content": "Results. The results are summarized in Table 3. It is observed that MIMO-DONeRF-16/4-naive outperformed DONeRF-4 in terms of PSNR and FLIP with a small increase in I-time and T-time. MIMO-DONeRF-16/4-self enhanced the image quality with an increase in T-time, and its image quality approached that of DONeRF-16 in terms of PSNR and FLIP with faster inference and training. These results suggest that the increase in " + }, + { + "bbox": [ + 305, + 344, + 545, + 488 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 305, + 344, + 545, + 488 + ], + "type": "text", + "content": " (i.e., the replacement of the SISO MLP by the MIMO MLP) can be used as an alternative to the reduction in " + }, + { + "bbox": [ + 305, + 344, + 545, + 488 + ], + "type": "inline_equation", + "content": "N_{s}" + }, + { + "bbox": [ + 305, + 344, + 545, + 488 + ], + "type": "text", + "content": " (the number of selected samples) to obtain a better trade-off between speed and quality. A detailed analysis is presented in Appendix A.8." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 498, + 440, + 510 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 498, + 440, + 510 + ], + "spans": [ + { + "bbox": [ + 306, + 498, + 440, + 510 + ], + "type": "text", + "content": "5.5. Application to TensoRF" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 517, + 545, + 673 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 517, + 545, + 673 + ], + "spans": [ + { + "bbox": [ + 305, + 517, + 545, + 673 + ], + "type": "text", + "content": "A NeRF with alternative representations is another representative fast approach. To demonstrate that MIMO-NeRF is also compatible with this model, we applied it to TensoRF [9], a representative model in this category. TensoRF uses a vector-matrix decomposition to calculate the volume densities and color features and applies a SISO MLP to the color features to decode the RGB colors. The corresponding ambiguity was relatively limited because the volume densities were extracted using an explicit representation. Hence, we simply replaced the SISO MLP with a MIMO MLP without modifying the training process while prioritizing training speed. These models are denoted as MIMOTensoRF-" + }, + { + "bbox": [ + 305, + 517, + 545, + 673 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 305, + 517, + 545, + 673 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 305, + 517, + 545, + 673 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 305, + 517, + 545, + 673 + ], + "type": "text", + "content": " was varied among " + }, + { + "bbox": [ + 305, + 517, + 545, + 673 + ], + "type": "inline_equation", + "content": "\\{2,4,8\\}" + }, + { + "bbox": [ + 305, + 517, + 545, + 673 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "content": "Dataset. We examined the performance of our approach on the Blender [39] and LLFF [38] datasets described in Section 5.1. Full-size images were used in this experiment." + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 46, + 673, + 287, + 702 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 673, + 287, + 702 + ], + "spans": [ + { + "bbox": [ + 46, + 673, + 287, + 702 + ], + "type": "text", + "content": "found that MIMO-NeRF-self achieved a better trade-off between speed and quality than the other variants. Detailed results are provided in Appendix A.4." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 58, + 703, + 265, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 703, + 265, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 703, + 265, + 712 + ], + "type": "text", + "content": "9https://github.com/facebookresearch/DONERF" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3280" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 68, + 287, + 188 + ], + "blocks": [ + { + "bbox": [ + 48, + 68, + 287, + 188 + ], + "lines": [ + { + "bbox": [ + 48, + 68, + 287, + 188 + ], + "spans": [ + { + "bbox": [ + 48, + 68, + 287, + 188 + ], + "type": "table", + "html": "
ModelPSNR↑SSIM↑# Run↓I-time↓(s)T-time↓(m)# Params(M)
TensoRF33.230.9639.951.2511.5018.8
MIMO-TensoRF-233.260.9634.761.1810.8918.8
MIMO-TensoRF-432.980.9612.401.1510.6718.8
MIMO-TensoRF-832.370.9561.271.1410.5718.9
(a) Blender
ModelPSNR↑SSIM↑# Run↓I-time↓(s)T-time↓(m)# Params(M)
TensoRF26.730.837126.736.6423.4146.8
MIMO-TensoRF-226.720.83762.146.1821.6346.8
MIMO-TensoRF-426.720.83630.165.7621.1546.8
MIMO-TensoRF-826.640.83514.525.5220.6846.9
(b) LLFF
", + "image_path": "1f60f53fc21a5bbe3c84ae434e4151288a5290774f3b3b4fcb6940b50ca18482.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 46, + 197, + 287, + 242 + ], + "lines": [ + { + "bbox": [ + 46, + 197, + 287, + 242 + ], + "spans": [ + { + "bbox": [ + 46, + 197, + 287, + 242 + ], + "type": "text", + "content": "Table 4. Comparison of quantitative scores between TensoRF and MIMO-TensoRF. MIMO-TensoRF improved I-time and T-time while retaining PSNR and SSIM when " + }, + { + "bbox": [ + 46, + 197, + 287, + 242 + ], + "type": "inline_equation", + "content": "N_{p} \\leq 2" + }, + { + "bbox": [ + 46, + 197, + 287, + 242 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 197, + 287, + 242 + ], + "type": "inline_equation", + "content": "N_{p} \\leq 4" + }, + { + "bbox": [ + 46, + 197, + 287, + 242 + ], + "type": "text", + "content": " on the Blender and LLFF datasets, respectively." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 261, + 287, + 310 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 261, + 287, + 310 + ], + "spans": [ + { + "bbox": [ + 46, + 261, + 287, + 310 + ], + "type": "text", + "content": "Implementation. We implemented the models based on the official source code of " + }, + { + "bbox": [ + 46, + 261, + 287, + 310 + ], + "type": "inline_equation", + "content": "\\mathrm{TensoRF^{10}}" + }, + { + "bbox": [ + 46, + 261, + 287, + 310 + ], + "type": "text", + "content": " and trained all the models using the same default settings for a fair comparison. The implementation details are presented in Appendix B.3." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 312, + 287, + 384 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 312, + 287, + 384 + ], + "spans": [ + { + "bbox": [ + 46, + 312, + 287, + 384 + ], + "type": "text", + "content": "Evaluation metrics. Following the study on TensoRF [9], we measured the image quality using PSNR and SSIM [64]. In addition, we used the # Run, I-time, T-time, and # Params described in Section 5.1. In TensoRF, # Run is determined adaptively for each pixel. Therefore, we report the average value." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "spans": [ + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "type": "text", + "content": "Results. The results are presented in Table 4. It is observed that MIMO-TensoRF improved I-time and T-time with similar image quality when " + }, + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "type": "text", + "content": " was set within an adequate range (in particular, " + }, + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "type": "inline_equation", + "content": "N_{p} \\leq 2" + }, + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "type": "text", + "content": " on the Blender dataset and " + }, + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "type": "inline_equation", + "content": "N_{p} \\leq 4" + }, + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "type": "text", + "content": " on the LLFF dataset). These results suggest that MIMO-TensoRF can strengthen the inference and training speed of TensoRF without negative effects by adequately selecting " + }, + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "type": "text", + "content": ". A detailed analysis is presented in Appendix A.9." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 506, + 117, + 519 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 506, + 117, + 519 + ], + "spans": [ + { + "bbox": [ + 47, + 506, + 117, + 519 + ], + "type": "text", + "content": "6. Discussion" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 527, + 287, + 694 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 527, + 287, + 694 + ], + "spans": [ + { + "bbox": [ + 46, + 527, + 287, + 694 + ], + "type": "text", + "content": "The results of these experiments in various situations demonstrate that MIMO-NeRF achieved a good trade-off between speed and quality. However, we also found that the quality degradation became significant with increasing " + }, + { + "bbox": [ + 46, + 527, + 287, + 694 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 46, + 527, + 287, + 694 + ], + "type": "text", + "content": ". One possible reason for this is that we did not modify the baseline network except for its input and output and did not increase the capacity of the models. It might be natural to implement a model of larger capacity to handle larger combinations of inputs and outputs. We did not adopt this strategy to ensure a fair comparison. However, searching for the best configurations considering the number of samples, the number of groups (the proposed new searching area), and the size of the model remain as a practically imperative and promising direction for further research." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 71, + 379, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 71, + 379, + 83 + ], + "spans": [ + { + "bbox": [ + 306, + 71, + 379, + 83 + ], + "type": "text", + "content": "7. Conclusion" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 91, + 545, + 258 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 91, + 545, + 258 + ], + "spans": [ + { + "bbox": [ + 304, + 91, + 545, + 258 + ], + "type": "text", + "content": "In this study, we have proposed MIMO-NeRF to improve the rendering speed of NeRF. Our core idea is that of replacing the SISO MLP used in standard NeRFs with a MIMO-MLP. We have developed a novel self-supervised learning method to address the ambiguity in the color and volume density of each point without relying on pretrained models. The results of an experimental evaluation have shown that MIMO-NeRF achieves a good trade-off between speed and quality with a reasonable training time. Although we have demonstrated the versatility of MIMO-NeRF by applying it to various NeRFs, many implicit neural representations aside from NeRFs also partially or primarily use SISO MLPs. We expect our ideas to be utilized with a few modifications to speed up the execution of such models." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 269, + 365, + 281 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 269, + 365, + 281 + ], + "spans": [ + { + "bbox": [ + 306, + 269, + 365, + 281 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 307, + 289, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 21, + "blocks": [ + { + "bbox": [ + 310, + 289, + 545, + 332 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 289, + 545, + 332 + ], + "spans": [ + { + "bbox": [ + 310, + 289, + 545, + 332 + ], + "type": "text", + "content": "[1] Pontus Andersson, Jim Nilsson, Tomas Akenine-Möller, Magnus Oskarsson, Kalle Åström, and Mark D. Fairchild. FLIP: A difference evaluator for alternating images. Proc. ACM Comput. Graph. Interact. Tech., 3(2), 2020. 8" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 311, + 334, + 545, + 366 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 334, + 545, + 366 + ], + "spans": [ + { + "bbox": [ + 311, + 334, + 545, + 366 + ], + "type": "text", + "content": "[2] Benjamin Attal, Jia-Bin Huang, Michael Zollhoefer, Johannes Kopf, and Changil Kim. Learning neural light fields with ray-space embedding networks. In CVPR, 2022. 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 311, + 367, + 545, + 388 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 367, + 545, + 388 + ], + "spans": [ + { + "bbox": [ + 311, + 367, + 545, + 388 + ], + "type": "text", + "content": "[3] Matan Atzmon and Yaron Lipman. SAL: Sign agnostic learning of shapes from raw data. In CVPR, 2020. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 311, + 390, + 545, + 433 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 390, + 545, + 433 + ], + "spans": [ + { + "bbox": [ + 311, + 390, + 545, + 433 + ], + "type": "text", + "content": "[4] Jonathan T. Barron, Ben Mildenhall, Matthew Tancik, Peter Hedman, Ricardo Martin-Brualla, and Pratul P. Srinivasan. Mip-NeRF: A multiscale representation for antiailiasing neural radiance fields. In ICCV, 2021. 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 311, + 434, + 545, + 466 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 434, + 545, + 466 + ], + "spans": [ + { + "bbox": [ + 311, + 434, + 545, + 466 + ], + "type": "text", + "content": "[5] Jonathan T. Barron, Ben Mildenhall, Dor Verbin, Pratul P. Srinivasan, and Peter Hedman. Mip-NeRF 360: Unbounded anti-aliased neural radiance fields. In CVPR, 2022. 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 311, + 468, + 545, + 511 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 468, + 545, + 511 + ], + "spans": [ + { + "bbox": [ + 311, + 468, + 545, + 511 + ], + "type": "text", + "content": "[6] Rohan Chabra, Jan E. Lenssen, Eddy Ilg, Tanner Schmidt, Julian Straub, Steven Lovegrove, and Richard Newcombe. Deep local shapes: Learning local SDF priors for detailed 3D reconstruction. In ECCV, 2020. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 311, + 513, + 545, + 577 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 513, + 545, + 577 + ], + "spans": [ + { + "bbox": [ + 311, + 513, + 545, + 577 + ], + "type": "text", + "content": "[7] Eric R. Chan, Connor Z. Lin, Matthew A. Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas J. Guibas, Jonathan Tremblay, Sameh Khamis, Tero Karras, and Gordon Wetzstein. Efficient geometry-aware 3D generative adversarial networks. In CVPR, 2022. 2, 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 311, + 579, + 545, + 622 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 579, + 545, + 622 + ], + "spans": [ + { + "bbox": [ + 311, + 579, + 545, + 622 + ], + "type": "text", + "content": "[8] Eric R. Chan, Marco Monteiro, Petr Kellnhofer, Jiajun Wu, and Gordon Wetzstein. pi-GAN: Periodic implicit generative adversarial networks for 3D-aware image synthesis. In CVPR, 2021. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 311, + 624, + 545, + 655 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 624, + 545, + 655 + ], + "spans": [ + { + "bbox": [ + 311, + 624, + 545, + 655 + ], + "type": "text", + "content": "[9] Anpei Chen, Zexiang Xu, Andreas Geiger, Jingyi Yu, and Hao Su. TensoRF: Tensorial radiance fields. In ECCV, 2022. 2, 3, 6, 8, 9" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 658, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 658, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 307, + 658, + 545, + 689 + ], + "type": "text", + "content": "[10] Xingyu Chen, Qi Zhang, Xiaoyu Li, Yue Chen, Ying Feng, Xuan Wang, and Jue Wang. Hallucinated neural radiance fields in the wild. In CVPR, 2022. 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 691, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 691, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 691, + 545, + 713 + ], + "type": "text", + "content": "[11] Zhiqin Chen and Hao Zhang. Learning implicit fields for generative shape modeling. In CVPR, 2019. 3" + } + ] + } + ], + "index": 20 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 55, + 702, + 236, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 702, + 236, + 712 + ], + "spans": [ + { + "bbox": [ + 55, + 702, + 236, + 712 + ], + "type": "text", + "content": "10https://github.com/apchenstu/TensoRF" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "3281" + } + ] + } + ], + "index": 23 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 17, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 105 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 105 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 105 + ], + "type": "text", + "content": "[12] Julian Chibane, Aymen Mir, and Gerard Pons-Moll. Neural unsigned distance fields for implicit function learning. In NeurIPS, 2020. 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 107, + 286, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 107, + 286, + 140 + ], + "spans": [ + { + "bbox": [ + 49, + 107, + 286, + 140 + ], + "type": "text", + "content": "[13] Yu Deng, Jiaolong Yang, Jianfeng Xiang, and Xin Tong. GRAM: Generative radiance manifolds for 3D-aware image generation. In CVPR, 2022. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 141, + 286, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 141, + 286, + 184 + ], + "spans": [ + { + "bbox": [ + 49, + 141, + 286, + 184 + ], + "type": "text", + "content": "[14] Jiemin Fang, Lingxi Xie, Xinggang Wang, Xiaopeng Zhang, Wenyu Liu, and Qi Tian. NeuSample: Neural sample field for efficient view synthesis. arXiv preprint arXiv:2111.15552, 2021. 2, 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 186, + 286, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 186, + 286, + 228 + ], + "spans": [ + { + "bbox": [ + 49, + 186, + 286, + 228 + ], + "type": "text", + "content": "[15] Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, 2022. 2, 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 231, + 286, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 231, + 286, + 262 + ], + "spans": [ + { + "bbox": [ + 49, + 231, + 286, + 262 + ], + "type": "text", + "content": "[16] Guy Gafni, Justus Thies, Michael Zollhofer, and Matthias Nießner. Dynamic neural radiance fields for monocular 4D facial avatar reconstruction. In CVPR, 2021. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 264, + 286, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 264, + 286, + 297 + ], + "spans": [ + { + "bbox": [ + 49, + 264, + 286, + 297 + ], + "type": "text", + "content": "[17] Stephan J. Garbin, Marek Kowalski, Matthew Johnson, Jamie Shotton, and Julien Valentin. FastNeRF: High-fidelity neural rendering at 200FPS. In ICCV, 2021. 2, 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 298, + 286, + 341 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 298, + 286, + 341 + ], + "spans": [ + { + "bbox": [ + 49, + 298, + 286, + 341 + ], + "type": "text", + "content": "[18] Kyle Genova, Forrester Cole, Daniel Vlasic, Aaron Sarna, William T. Freeman, and Thomas Funkhouser. Learning shape templates with structured implicit functions. In ICCV, 2019. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 343, + 286, + 385 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 343, + 286, + 385 + ], + "spans": [ + { + "bbox": [ + 49, + 343, + 286, + 385 + ], + "type": "text", + "content": "[19] Ian J. Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In NIPS, 2014. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 388, + 286, + 420 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 388, + 286, + 420 + ], + "spans": [ + { + "bbox": [ + 49, + 388, + 286, + 420 + ], + "type": "text", + "content": "[20] Amos Gropp, Lior Yariv, Niv Haim, Matan Atzmon, and Yaron Lipman. Implicit geometric regularization for learning shapes. In ICML, 2020. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 422, + 286, + 454 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 422, + 286, + 454 + ], + "spans": [ + { + "bbox": [ + 49, + 422, + 286, + 454 + ], + "type": "text", + "content": "[21] Jiatao Gu, Lingjie Liu, Peng Wang, and Christian Theobalt. StyleNeRF: A style-based 3D-aware generator for high-resolution image synthesis. In ICLR, 2022. 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 456, + 286, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 456, + 286, + 498 + ], + "spans": [ + { + "bbox": [ + 49, + 456, + 286, + 498 + ], + "type": "text", + "content": "[22] Peter Hedman, Pratul P. Srinivasan, Ben Mildenhall, Jonathan T. Barron, and Paul Debevec. Baking neural radiance fields for real-time view synthesis. In ICCV, 2021. 2, 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 49, + 501, + 286, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 501, + 286, + 521 + ], + "spans": [ + { + "bbox": [ + 49, + 501, + 286, + 521 + ], + "type": "text", + "content": "[23] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. In NeurIPS, 2020. 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 49, + 523, + 286, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 523, + 286, + 555 + ], + "spans": [ + { + "bbox": [ + 49, + 523, + 286, + 555 + ], + "type": "text", + "content": "[24] Tao Hu, Shu Liu, Yilun Chen, Tiancheng Shen, and Jiaya Jia. EfficientNeRF: Efficient neural radiance fields. In CVPR, 2022. 2, 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 49, + 557, + 286, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 557, + 286, + 600 + ], + "spans": [ + { + "bbox": [ + 49, + 557, + 286, + 600 + ], + "type": "text", + "content": "[25] Chiyu Max Jiang, Avneesh Sud, Ameesh Makadia, Jingwei Huang, Matthias Nießner, and Thomas Funkhouser. Local implicit grid representations for 3D scenes. In CVPR, 2020. 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 49, + 602, + 286, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 602, + 286, + 635 + ], + "spans": [ + { + "bbox": [ + 49, + 602, + 286, + 635 + ], + "type": "text", + "content": "[26] Takuhiro Kaneko. AR-NeRF: Unsupervised learning of depth and defocus effects from natural images with aperture rendering neural radiance fields. In CVPR, 2022. 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 49, + 636, + 286, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 636, + 286, + 678 + ], + "spans": [ + { + "bbox": [ + 49, + 636, + 286, + 678 + ], + "type": "text", + "content": "[27] Andreas Kurz, Thomas Neff, Zhaoyang Lv, Michael Zollhöfer, and Markus Steinberger. AdaNeRF: Adaptive sampling for real-time rendering of neural radiance fields. In ECCV, 2022. 2, 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 49, + 681, + 286, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 681, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 49, + 681, + 286, + 713 + ], + "type": "text", + "content": "[28] Chen-Hsuan Lin, Chaoyang Wang, and Simon Lucey. SDF-SRN: Learning signed distance 3D object reconstruction from static images. In NeurIPS, 2020. 1, 3" + } + ] + } + ], + "index": 16 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 33, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "text", + "content": "[29] David B. Lindell, Julien N. P. Martel, and Gordon Wetzstein. AutoInt: Automatic integration for fast neural volume rendering. In CVPR, 2021. 2, 3" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 108, + 545, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 108, + 545, + 140 + ], + "spans": [ + { + "bbox": [ + 307, + 108, + 545, + 140 + ], + "type": "text", + "content": "[30] Lingjie Liu, Jiatao Gu, Kyaw Zaw Lin, Tat-Seng Chua, and Christian Theobalt. Neural sparse voxel fields. In NeurIPS, 2020. 2, 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 143, + 545, + 175 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 143, + 545, + 175 + ], + "spans": [ + { + "bbox": [ + 307, + 143, + 545, + 175 + ], + "type": "text", + "content": "[31] Shichen Liu, Shunsuke Saito, Weikai Chen, and Hao Li. Learning to infer implicit surfaces without 3D supervision. In NeurIPS, 2019. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 178, + 545, + 220 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 178, + 545, + 220 + ], + "spans": [ + { + "bbox": [ + 307, + 178, + 545, + 220 + ], + "type": "text", + "content": "[32] Shaohui Liu, Yinda Zhang, Songyou Peng, Boxin Shi, Marc Pollefeys, and Zhaopeng Cui. DIST: Rendering deep implicit signed distance function with differentiable sphere tracing. In CVPR, 2020. 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 224, + 545, + 266 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 224, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 307, + 224, + 545, + 266 + ], + "type": "text", + "content": "[33] Ricardo Martin-Brualla, Noha Radwan, Mehdi S. M. Sajjadi, Jonathan T. Barron, Alexey Dosovitskiy, and Daniel Duckworth. NeRF in the wild: Neural radiance fields for unconstrained photo collections. In CVPR, 2021. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 270, + 545, + 291 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 270, + 545, + 291 + ], + "spans": [ + { + "bbox": [ + 307, + 270, + 545, + 291 + ], + "type": "text", + "content": "[34] Nelson Max. Optical models for direct volume rendering. IEEE Trans. Vis. Comput. Graph., 1(2), 1995. 1, 3, 4" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 293, + 545, + 335 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 293, + 545, + 335 + ], + "spans": [ + { + "bbox": [ + 307, + 293, + 545, + 335 + ], + "type": "text", + "content": "[35] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3D reconstruction in function space. In CVPR, 2019. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 338, + 545, + 380 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 338, + 545, + 380 + ], + "spans": [ + { + "bbox": [ + 307, + 338, + 545, + 380 + ], + "type": "text", + "content": "[36] Mateusz Michalkiewicz, Jhony K. Pontes, Dominic Jack, Mahsa Baktashmotlagh, and Anders Eriksson. Implicit surface representations as layers in neural networks. In ICCV, 2019. 3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 384, + 545, + 427 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 384, + 545, + 427 + ], + "spans": [ + { + "bbox": [ + 307, + 384, + 545, + 427 + ], + "type": "text", + "content": "[37] Ben Mildenhall, Peter Hedman, Ricardo Martin-Brualla, Pratul P. Srinivasan, and Jonathan T. Barron. NeRF in the dark: High dynamic range view synthesis from noisy raw images. In CVPR, 2022. 3" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 430, + 545, + 484 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 430, + 545, + 484 + ], + "spans": [ + { + "bbox": [ + 307, + 430, + 545, + 484 + ], + "type": "text", + "content": "[38] Ben Mildenhall, Pratul P. Srinivasan, Rodrigo Ortiz-Cayon, Nima Khademi Kalantari, Ravi Ramamoorthi, Ren Ng, and Abhishek Kar. Local light field fusion: Practical view synthesis with prescriptive sampling guidelines. ACM Trans. Graph., 38(4), 2019. 6, 8" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 487, + 545, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 487, + 545, + 529 + ], + "spans": [ + { + "bbox": [ + 307, + 487, + 545, + 529 + ], + "type": "text", + "content": "[39] Ben Mildenhall, Pratul P. Srinivasan, Matthew Tancik, Jonathan T. Barron, Ravi Ramamoorthi, and Ren Ng. NeRF: Representing scenes as neural radiance fields for view synthesis. In ECCV, 2020. 1, 3, 6, 8" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 533, + 545, + 574 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 533, + 545, + 574 + ], + "spans": [ + { + "bbox": [ + 307, + 533, + 545, + 574 + ], + "type": "text", + "content": "[40] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Trans. Graph., 41(4), 2022. 2, 3" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 578, + 545, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 578, + 545, + 643 + ], + "spans": [ + { + "bbox": [ + 307, + 578, + 545, + 643 + ], + "type": "text", + "content": "[41] Thomas Neff, Pascal Stadlbauer, Mathias Parger, Andreas Kurz, Joerg H. Mueller, Chakravarty R. Alla Chaitanya, Anton Kaplanyan, and Markus Steinberger. DONeRF: Towards real-time rendering of compact neural radiance fields using depth oracle networks. Comput. Graph. Forum, 40(4), 2021. 2, 3, 6, 8" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 307, + 646, + 545, + 677 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 646, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 307, + 646, + 545, + 677 + ], + "type": "text", + "content": "[42] Michael Niemeyer and Andreas Geiger. CAMPARI: Camera-aware decomposed generative neural radiance fields. In 3DV, 2021. 3" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 307, + 681, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 681, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 681, + 545, + 712 + ], + "type": "text", + "content": "[43] Michael Niemeyer and Andreas Geiger. GIRAFFE: Representing scenes as compositional generative neural feature fields. In CVPR, 2021. 3" + } + ] + } + ], + "index": 32 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "3282" + } + ] + } + ], + "index": 34 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 17, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[44] Michael Niemeyer, Lars Mescheder, Michael Oechsle, and Andreas Geiger. Differentiable volumetric rendering: Learning implicit 3D representations without 3D supervision. In CVPR, 2020. 1, 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 118, + 287, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 118, + 287, + 161 + ], + "spans": [ + { + "bbox": [ + 48, + 118, + 287, + 161 + ], + "type": "text", + "content": "[45] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. DeepSDF: Learning continuous signed distance functions for shape representation. In CVPR, 2019. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 163, + 287, + 195 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 163, + 287, + 195 + ], + "spans": [ + { + "bbox": [ + 48, + 163, + 287, + 195 + ], + "type": "text", + "content": "[46] Songyou Peng, Michael Niemeyer, Lars Mescheder, Marc Pollefeys, and Andreas Geiger. Convolutional occupancy networks. In ECCV, 2020. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 197, + 287, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 197, + 287, + 228 + ], + "spans": [ + { + "bbox": [ + 48, + 197, + 287, + 228 + ], + "type": "text", + "content": "[47] Martin Piala and Ronald Clark. TermiNeRF: Ray termination prediction for efficient neural rendering. In 3DV, 2021. 2, 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 230, + 287, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 230, + 287, + 262 + ], + "spans": [ + { + "bbox": [ + 48, + 230, + 287, + 262 + ], + "type": "text", + "content": "[48] Ben Poole, Ajay Jain, Jonathan T. Barron, and Ben Mildenhall. DreamFusion: Text-to-3D using 2D diffusion. In ICLR, 2023. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 264, + 287, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 264, + 287, + 297 + ], + "spans": [ + { + "bbox": [ + 48, + 264, + 287, + 297 + ], + "type": "text", + "content": "[49] Albert Pumarola, Enric Corona, Gerard Pons-Moll, and Francesc Moreno-Noguer. D-NeRF: Neural radiance fields for dynamic scenes. In CVPR, 2021. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 298, + 287, + 331 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 298, + 287, + 331 + ], + "spans": [ + { + "bbox": [ + 48, + 298, + 287, + 331 + ], + "type": "text", + "content": "[50] Daniel Rebain, Wei Jiang, Soroosh Yazdani, Ke Li, Kwang Moo Yi, and Andrea Tagliasacchi. DeRF: Decomposed radiance fields. In CVPR, 2021. 2, 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 332, + 287, + 364 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 332, + 287, + 364 + ], + "spans": [ + { + "bbox": [ + 48, + 332, + 287, + 364 + ], + "type": "text", + "content": "[51] Christian Reiser, Songyou Peng, Yiyi Liao, and Andreas Geiger. KiloNeRF: Speeding up neural radiance fields with thousands of tiny MLPs. In ICCV, 2021. 2, 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 365, + 287, + 409 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 365, + 287, + 409 + ], + "spans": [ + { + "bbox": [ + 48, + 365, + 287, + 409 + ], + "type": "text", + "content": "[52] Shunsuke Saito, Zeng Huang, Ryota Natsume, Shigeo Morishima, Angjoo Kanazawa, and Hao Li. PIFu: Pixel-aligned implicit function for high-resolution clothed human digitization. In ICCV, 2019. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 411, + 287, + 443 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 411, + 287, + 443 + ], + "spans": [ + { + "bbox": [ + 48, + 411, + 287, + 443 + ], + "type": "text", + "content": "[53] Katja Schwarz, Yiyi Liao, Michael Niemeyer, and Andreas Geiger. GRAF: Generative radiance fields for 3D-aware image synthesis. In NeurIPS, 2020. 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 445, + 287, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 445, + 287, + 487 + ], + "spans": [ + { + "bbox": [ + 48, + 445, + 287, + 487 + ], + "type": "text", + "content": "[54] Vincent Sitzmann, Julien Martel, Alexander Bergman, David Lindell, and Gordon Wetzstein. Implicit neural representations with periodic activation functions. In NeurIPS, 2020. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 489, + 287, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 489, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 48, + 489, + 287, + 533 + ], + "type": "text", + "content": "[55] Vincent Sitzmann, Semon Rezchikov, Bill Freeman, Josh Tenenbaum, and Fredo Durand. Light field networks: Neural scene representations with single-evaluation rendering. In NeurIPS, 2021. 1, 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 534, + 287, + 577 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 534, + 287, + 577 + ], + "spans": [ + { + "bbox": [ + 48, + 534, + 287, + 577 + ], + "type": "text", + "content": "[56] Vincent Sitzmann, Michael Zollhöfer, and Gordon Wetzstein. Scene representation networks: Continuous 3D-structure-aware neural scene representations. In NeurIPS, 2019. 1, 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 578, + 287, + 611 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 578, + 287, + 611 + ], + "spans": [ + { + "bbox": [ + 48, + 578, + 287, + 611 + ], + "type": "text", + "content": "[57] Ivan Skorokhodov, Sergey Tulyakov, Yiqun Wang, and Peter Wonka. EpiGRAF: Rethinking training of 3D GANs. In NeurIPS, 2022. 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 613, + 287, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 613, + 287, + 644 + ], + "spans": [ + { + "bbox": [ + 48, + 613, + 287, + 644 + ], + "type": "text", + "content": "[58] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. In NeurIPS, 2019. 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 647, + 287, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 287, + 678 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 287, + 678 + ], + "type": "text", + "content": "[59] Mohammed Suhail, Carlos Esteves, Leonid Sigal, and Ameesh Makadia. Light field neural rendering. In CVPR, 2022. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 680, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 680, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 680, + 287, + 712 + ], + "type": "text", + "content": "[60] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In CVPR, 2022. 2, 3" + } + ] + } + ], + "index": 16 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 600 + ], + "type": "list", + "angle": 0, + "index": 31, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 127 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 127 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 127 + ], + "type": "text", + "content": "[61] Matthew Tancik, Pratul P. Srinivasan, Ben Mildenhall, Sara Fridovich-Keil, Nithin Raghavan, Utkarsh Singhal, Ravi Ramamoorthi, Jonathan T. Barron, and Ren Ng. Fourier features let networks learn high frequency functions in low dimensional domains. In NeurIPS, 2020. 3" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 129, + 545, + 172 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 129, + 545, + 172 + ], + "spans": [ + { + "bbox": [ + 307, + 129, + 545, + 172 + ], + "type": "text", + "content": "[62] Dor Verbin, Peter Hedman, Ben Mildenhall, Todd Zickler, Jonathan T. Barron, and Pratul P. Srinivasan. Ref-NeRF: Structured view-dependent appearance for neural radiance fields. In CVPR, 2022. 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 174, + 545, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 174, + 545, + 217 + ], + "spans": [ + { + "bbox": [ + 307, + 174, + 545, + 217 + ], + "type": "text", + "content": "[63] Huan Wang, Jian Ren, Zeng Huang, Kyle Olszewski, Mengei Chai, Yun Fu, and Sergey Tulyakov. R2L: Distilling neural radiance field to neural light field for efficient novel view synthesis. In ECCV, 2022. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 219, + 545, + 261 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 219, + 545, + 261 + ], + "spans": [ + { + "bbox": [ + 307, + 219, + 545, + 261 + ], + "type": "text", + "content": "[64] Zhou Wang, Alan C. Bovik, Hamid R. Sheikh, and Eero P. Simoncelli. Image quality assessment: From error visibility to structural similarity. IEEE Trans. Image Process., 13(4), 2004. 6, 9" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 263, + 545, + 306 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 263, + 545, + 306 + ], + "spans": [ + { + "bbox": [ + 307, + 263, + 545, + 306 + ], + "type": "text", + "content": "[65] Suttisak Wizadwongsa, Pakkapon Phongthawee, Jiraphon Yenphraphai, and Supasorn Suwajanakorn. NeX: Real-time view synthesis with neural basis expansion. In CVPR, 2021. 2, 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 308, + 545, + 352 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 308, + 545, + 352 + ], + "spans": [ + { + "bbox": [ + 307, + 308, + 545, + 352 + ], + "type": "text", + "content": "[66] Liwen Wu, Jae Yong Lee, Anand Bhattachad, Yu-Xiong Wang, and David Forsyth. DIVeR: Real-time and accurate neural radiance fields with deterministic integration for volume rendering. In CVPR, 2022. 2, 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 354, + 545, + 385 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 354, + 545, + 385 + ], + "spans": [ + { + "bbox": [ + 307, + 354, + 545, + 385 + ], + "type": "text", + "content": "[67] Wenqi Xian, Jia-Bin Huang, Johannes Kopf, and Changil Kim. Space-time neural irradiance fields for free-viewpoint video. In CVPR, 2021. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 387, + 545, + 419 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 387, + 545, + 419 + ], + "spans": [ + { + "bbox": [ + 307, + 387, + 545, + 419 + ], + "type": "text", + "content": "[68] Yang Xue, Yuheng Li, Krishna Kumar Singh, and Yong Jae Lee. GIRAFFE HD: A high-resolution 3D-aware generative model. In CVPR, 2022. 3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 421, + 545, + 464 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 421, + 545, + 464 + ], + "spans": [ + { + "bbox": [ + 307, + 421, + 545, + 464 + ], + "type": "text", + "content": "[69] Lior Yariv, Yoni Kasten, Dror Moran, Meirav Galun, Matan Atzmon, Basri Ronen, and Yaron Lipman. Multiview neural surface reconstruction by disentangling geometry and appearance. In NeurIPS, 2020. 1, 3" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 466, + 545, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 466, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 307, + 466, + 545, + 498 + ], + "type": "text", + "content": "[70] Alex Yu, Ruilong Li, Matthew Tancik, Hao Li, Ren Ng, and Angjoo Kanazawa. PlenOctrees for real-time rendering of neural radiance fields. In ICCV, 2021. 2, 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 499, + 545, + 532 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 499, + 545, + 532 + ], + "spans": [ + { + "bbox": [ + 307, + 499, + 545, + 532 + ], + "type": "text", + "content": "[71] Alex Yu, Vickie Ye, Matthew Tancik, and Angjoo Kanazawa. PixelNeRF: Neural radiance fields from one or few images. In CVPR, 2021. 1, 3" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 533, + 545, + 566 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 533, + 545, + 566 + ], + "spans": [ + { + "bbox": [ + 307, + 533, + 545, + 566 + ], + "type": "text", + "content": "[72] Kai Zhang, Gernot Riegler, Noah Snavely, and Vladlen Koltun. NeRF++: Analyzing and improving neural radiance fields. arXiv preprint arXiv:2010.07492, 2020.3" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 567, + 545, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 567, + 545, + 600 + ], + "spans": [ + { + "bbox": [ + 307, + 567, + 545, + 600 + ], + "type": "text", + "content": "[73] Richard Zhang, Phillip Isola, Alexei A. Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In CVPR, 2018. 6" + } + ] + } + ], + "index": 30 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3283" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/8b54a15b-f3ee-46da-88b3-5c8950b9cb49_content_list.json b/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/8b54a15b-f3ee-46da-88b3-5c8950b9cb49_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..e7f7880594c2d1e46e9ec643b172eafe25cf4bfb --- /dev/null +++ b/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/8b54a15b-f3ee-46da-88b3-5c8950b9cb49_content_list.json @@ -0,0 +1,1556 @@ +[ + { + "type": "text", + "text": "MMST-ViT: Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer", + "text_level": 1, + "bbox": [ + 104, + 128, + 867, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Fudong Lin $^{1}$ , Summer Crawford $^{2}$ , Kaleb Guillot $^{2}$ , Yihe Zhang $^{2}$ , Yan Chen $^{3}$ , Xu Yuan $^{1*}$ , Li Chen $^{2}$ , Shelby Williams $^{2}$ , Robert Minvielle $^{2}$ , Xiangming Xiao $^{4}$ , Drew Gholson $^{5}$ , Nicolas Ashwell $^{5}$ , Tri Setiyono $^{6}$ , Brenda Tubana $^{7}$ , Lu Peng $^{8}$ , Magdy Bayoumi $^{2}$ , Nian-Feng Tzeng $^{2}$ $^{1}$ University of Delaware, $^{2}$ University of Louisiana at Lafayette, $^{3}$ University of Connecticut, $^{4}$ University of Oklahoma, $^{5}$ Mississippi State University, $^{6}$ Louisiana State University, $^{7}$ LSU AgCenter, $^{8}$ Tulane University", + "bbox": [ + 84, + 202, + 908, + 310 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 344, + 313, + 359 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Precise crop yield prediction provides valuable information for agricultural planning and decision-making processes. However, timely predicting crop yields remains challenging as crop growth is sensitive to growing season weather variation and climate change. In this work, we develop a deep learning-based solution, namely Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), for predicting crop yields at the county level across the United States, by considering the effects of short-term meteorological variations during the growing season and the long-term climate change on crops. Specifically, our MMST-ViT consists of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer. The Multi-Modal Transformer leverages both visual remote sensing data and short-term meteorological data for modeling the effect of growing season weather variations on crop growth. The Spatial Transformer learns the high-resolution spatial dependency among counties for accurate agricultural tracking. The Temporal Transformer captures the long-range temporal dependency for learning the impact of long-term climate change on crops. Meanwhile, we also devise a novel multi-modal contrastive learning technique to pre-train our model without extensive human supervision. Hence, our MMST-ViT captures the impacts of both short-term weather variations and long-term climate change on crops by leveraging both satellite images and meteorological data. We have conducted extensive experiments on over 200 counties in the United States, with the experimental results exhibiting that our MMST-ViT outperforms its counterparts under three performance metrics of interest. Our dataset and code are available at https://github.com/fudong03/MMST-ViT.", + "bbox": [ + 75, + 376, + 473, + 859 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 501, + 344, + 630, + 359 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Accurate crop yield prediction is essential for agricultural planning and advisory processes [26], informed economic decisions [2], and global food security [36]. However, predicting crop yields precisely is challenging as it requires to consider the effects of i) short-term weather variations, governed by the meteorological data during the growing season, and ii) long-term climate change, governed by historical meteorological factors, on crops simultaneously. Meanwhile, precise crop tracking relies on high-resolution remote sensing data. While process-based prediction approaches [44, 11, 25, 54] exist, they often suffer from high inaccuracies due to their strong assumptions on management practices [15]. On the other hand, motivated by the recent success of deep neural networks [29, 19, 50, 12, 20, 56, 37, 32, 18, 30, 8], deep learning (DL)-based methods have been widely adopted for crop yield predictions, due to their effectiveness in accurate agricultural tracking [27, 26] and their potent capabilities in capturing the spatial and temporal variation of meteorological data [28, 15].", + "bbox": [ + 496, + 369, + 893, + 672 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "So far, DL-based solutions for crop yield predictions can be roughly grouped into two categories, i.e., remote sensing data-based and meteorological data-based approaches. The former [27, 26, 53, 13, 17, 47, 10] employs such remote sensing data as satellite images, unmanned aerial vehicle (UAV)-based imagery data, or vegetation indices to estimate the annual crop yield, while the latter [16, 1, 36, 42, 48] predicts the crop yield by using meteorological parameter data, including temperature, precipitation, vapor pressure deficit, etc. However, the former overlooks the direct impact of meteorological parameters on crop growth, while the latter lacks high-resolution remote sensing data for accurate agricultural tracking.", + "bbox": [ + 496, + 672, + 893, + 869 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "A recent study [39] has reported that the long-term climate change would gradually decrease the crop yield.", + "bbox": [ + 498, + 869, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding author: Dr. Xu Yuan (xyuan@udel.edu)", + "bbox": [ + 94, + 886, + 393, + 900 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "5774", + "bbox": [ + 482, + 944, + 516, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Driven by this discovery, follow-up pursuits have attempted to explore the effect of long-term climate change on crops. For example, the CNN-RNN model [28] demonstrates that the crop yield prediction can benefit from historical meteorological data, which is essential for measuring the impacts of climate change. Later, GNN-RNN [15] extends CNN-RNN by framing the crop yield prediction as the Spatial-Temporal forecasting problem. It employs Graph Neural Networks (GNN) and Long Short-Term Memory (LSTM) [22] respectively for learning spatial dependency among neighborhood counties and for capturing the impact of long-term meteorological data on crops. However, both of them only take into account the meteorological data for predictions, failing to leverage the remote sensing data for accurate agricultural tracking.", + "bbox": [ + 80, + 90, + 467, + 316 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this work, we aim to develop a new DL-based solution for predicting crop yields at the county level across the United States, by using both visual remote sensing data (from the Sentinel-2 satellite imagery [41]) and numerical meteorological data (from the HRRR model [24]). Our solution has two main goals. First, it captures the impacts of both short-term growing season weather variations and long-term climate change on crops. Second, it aims to leverage high-resolution remote sensing data for accurate agricultural tracking. To achieve our goals, we propose the Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), motivated by the recent success of Vision Transformers (ViT) [12]. To the best of our knowledge, MMST-ViT is the first ViT-based model for real-world crop yield prediction. It advances previous CNN/GNN-based and RNN-based counterparts respectively with better generalization to the multi-model data and with more powerful abilities in capturing long-term temporal dependency. Its three components of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer are each equipped with one novel Multi-Head Attention (MHA) mechanism [50]. Specifically, the Multi-Modal Transformer leverages satellite images and meteorological data during the growing season for capturing the direct impact of short-term weather variations on crop growth. The Spatial Transformer learns high-resolution spatial dependency among counties for precise crop tracking. The Temporal Transformer captures the effects of long-term climate change on crops. Since ViT-based models are prone to overfitting [12], we also develop a novel multi-modal contrastive learning technique that pre-trains our Multi-Modal Transformer without requiring human supervision. We have conducted experiments on over 200 counties in the United States. The experimental results exhibit that our MMST-ViT outperforms its state-of-the-art counterparts under three performance metrics of interest. For example, on the soybean prediction, our MMST-ViT achieves the lowest Root Mean Square Error (RMSE) value of 3.9, the highest R", + "bbox": [ + 80, + 325, + 467, + 898 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "squared $(\\mathbb{R}^2)$ value of 0.843, and the best Pearson Correlation Coefficient (Corr) value of 0.918.", + "bbox": [ + 503, + 92, + 888, + 119 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 503, + 138, + 638, + 152 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Vision Transformers. Adopted from Transformers [50] in natural language processing, Vision Transformers (ViT) have exhibited commendable performance in various computer vision tasks. The original ViT [12] first partitions an image into a set of image patches, then applies Multi-Head Attention (MHA) [50] over the patches, and finally utilizes a learnable classification token to capture global visual representation for image classification. Several subsequent methods have been developed, including DeiT [46] for data-efficient ViT through knowledge distillation, Swin [33] for computation-efficient ViT using shifted windows, PVT [51] for dense prediction tasks, and MAE [18] for self-supervised learning, among others [7, 21, 14, 55, 3, 52, 31, 45]. However, applying prior ViT approaches to real-world crop yield prediction is challenging due to its needs of addressing the multi-modal inputs, of learning high-resolution spatial dependency, and of capturing long-range temporal dependency. Our work, based on ViT, advances existing methods by proposing three novel Multi-Head Attention (MHA) mechanisms respectively for leveraging both visual remote sensing data and numerical meteorological data, learning global spatial representation from multiple high-resolution data, and capturing the global temporal representation for measuring the long-term climate change effect. Additionally, we develop a new multi-modal contrastive learning technique to pre-train our multi-modal model for better prediction performance.", + "bbox": [ + 503, + 170, + 888, + 575 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Deep Learning (DL) for Crop Yield Prediction. DL has been widely adopted for real-world crop yield predictions. Such prediction studies can be grouped into two categories: remote sensing data-based and meteorological data-based approaches. The former uses satellite images, unmanned aerial vehicle (UAV) data, or vegetation indices to estimate crop yields. Its prominent studies include the use of UAV-acquired RGB images [27] for predicting in-season crop yields, YieldNet [26] which resorts to transfer learning for simultaneously estimating the yields of multiple crop types, among many others [53, 13, 17, 47, 10]. By contrast, the latter utilizes deep neural networks (DNNs) to capture the impact of meteorological parameters on crop yields, including CNN-RNN [28] which incorporates long-term meteorological data, GNN-RNN [15] which extends CNN-RNN by using Graph Neural Networks (GNN) for learning spatial information, and others [16, 1, 36, 42, 48]. However, the remote sensing data-based solutions overlook the impact of meteorological parameters on crops, while the meteorological data-based solutions often fail to incorporate the remote sensing data, known to be crucial for accurate agricultural", + "bbox": [ + 503, + 584, + 888, + 898 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "5775", + "bbox": [ + 483, + 946, + 513, + 955 + ], + "page_idx": 1 + }, + { + "type": "table", + "img_path": "images/3a1ea68fc26358692057299737efb5d316530130db5e7737879d0cc18769bbf8.jpg", + "table_caption": [ + "Table 1: Overview of USDA Crop Dataset and HRRR Computed Dataset" + ], + "table_footnote": [], + "table_body": "
DatasetParameters
USDAProduction, Yield
HRRRAveraged Temperature, Maximal Temperature, Minimal Temperature, Precipitation, Relative Humidity, Wind Gust, Wind Speed, Downward Shortwave Radiation Flux, Vapor Pressure Deficit
", + "bbox": [ + 76, + 127, + 470, + 199 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "tracking. Our work differs from prior studies in two aspects. First, it leverages both remote sensing data and meteorological data for capturing the impacts of both short-term growing season meteorological variations and the long-term climate change on crops. Second, it is the first to use Vision Transformers for crop yield predictions, advancing previous CNN/GNN- and RNN-based models respectively with better generalization to multi-modal data and with higher abilities for capturing long ranges of temporal dependency.", + "bbox": [ + 75, + 214, + 470, + 351 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Datasets", + "text_level": 1, + "bbox": [ + 76, + 366, + 171, + 382 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this study, we utilize three types of data for accurate county-level crop yield predictions: i) crop data from the United States Department of Agriculture (USDA), ii) meteorological data from the High-Resolution Rapid Refresh (HRRR), and iii) remote sensing data from the Sentinel-2 satellite, as outlined below.", + "bbox": [ + 75, + 391, + 468, + 481 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "USDA Crop Dataset. The dataset, sourced from the United States Department of Agriculture (USDA) [49], provides annual crop data for major crops grown in the United States (U.S.), including corn, cotton, soybean, winter wheat, etc., on a county-level basis. It covers crop information such as production and yield from 2017 to 2022 (as listed in the second row of Table 1).", + "bbox": [ + 75, + 486, + 468, + 593 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "HRRR Computed Dataset. The dataset, obtained from the High-Resolution Rapid Refresh atmospheric model (HRRR) [24], provides high-resolution meteorological data for the contiguous U.S. continent. It covers 9 weather parameters from 2017 to 2022 (see the third row in Table 1 for more information).", + "bbox": [ + 75, + 597, + 468, + 688 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Sentinel-2 Imagery. Sentinel-2 imagery is a set of images captured by the Sentinel-2 Earth observation satellite. It provides agriculture imagery for the contiguous U.S. continent from 2017 to 2022 with a 2-week interval. Since precise agricultural tracking requires high-resolution remote sensing data, the image of a county is partitioned into multiple fine-grained grids $(9 \\times 9 \\mathrm{~km})$ . Figure 1 shows an example of county partitioning.", + "bbox": [ + 75, + 691, + 470, + 814 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4. Method", + "text_level": 1, + "bbox": [ + 76, + 829, + 166, + 844 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this work, we aim to develop a deep learning (DL)-based model for predicting crop yields at the county level. Our goals are twofold. First, we plan to capture the mete", + "bbox": [ + 75, + 854, + 468, + 900 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/a54ab7a758f291608607098d9237ba1146b2a18e99e9153ebcb5addbdf5ba50d.jpg", + "image_caption": [ + "(a) Grid Example" + ], + "image_footnote": [], + "bbox": [ + 511, + 92, + 694, + 268 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/dce3b4c54d71d6cf4be6283f648381fab365ad2cdc8561a66846f80a56ecd2b4.jpg", + "image_caption": [ + "(b) Sentinel-2 Imagery", + "Figure 1: Illustration of partitioning a county into multiple grids at the $9\\mathrm{km}$ high-resolution. (a) An example of county partitioning, with the red line segments indicating the geometry boundary for the county and the blue line segments representing the high-resolution grids. (b) The resulting satellite images in the Sentinel-2 Imagery, with each composed of $384\\times 384$ pixels, depicting an area of $9\\times 9\\mathrm{km}$ ." + ], + "image_footnote": [], + "bbox": [ + 702, + 93, + 877, + 272 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "orological effect, including growing season weather variations and climate change, on crop yields. Second, we aim to leverage high-resolution satellite images for precise agricultural tracking. The aforementioned three data sources are utilized for achieving our goals.", + "bbox": [ + 496, + 412, + 890, + 491 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4.1. Problem Statement", + "text_level": 1, + "bbox": [ + 500, + 497, + 684, + 512 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We consider the combination of four types of data $(\\boldsymbol{x},\\boldsymbol{y}_s,\\boldsymbol{y}_l,\\boldsymbol{z})$ for predicting the crop yield at each single U.S. county. Specifically, $\\boldsymbol{x} \\in \\mathbb{R}^{T \\times G \\times H \\times W \\times C}$ represents satellite images obtained from Sentinel-2 imagery, which capture the information of field crops on the ground. $T$ and $G$ indicate the numbers of temporal and spatial data, respectively, whereas $H$ , $W$ , and $C$ are the height, width, and number of channels in the satellite image. $\\boldsymbol{y}_s \\in \\mathbb{R}^{T \\times G \\times N_1 \\times d_y}$ and $\\boldsymbol{y}_l \\in \\mathbb{R}^{T \\times N_2 \\times d_y}$ are meteorological parameters obtained from the HRRR dataset, representing the short-term and the long-term historical data, respectively. Here, $N_1$ and $N_2$ are the numbers of daily and monthly HRRR data points, respectively, and $d_y$ indicates the number of weather parameters. Note that the short-term meteorological data is the daily HRRR data during the growing season, while the long-term historical meteorological data is the monthly HRRR data from the past several years (e.g., 2018 to 2020 for predicting crop yields in 2021). $\\boldsymbol{z} \\in \\mathbb{R}^{d_z}$ is the ground-truth crop information obtained from the USDA dataset, with $d_z$ representing the number of parameters for the crop data.", + "bbox": [ + 496, + 521, + 890, + 839 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4.2. Challenges", + "text_level": 1, + "bbox": [ + 500, + 847, + 620, + 863 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Three challenges exist upon achieving our goals, outlined as follows.", + "bbox": [ + 500, + 869, + 888, + 898 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "5776", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/151c8dbafb88e4fed7282f7383b6312254dcc2ee892d00bba8f0323d7cc6bffc.jpg", + "image_caption": [ + "Figure 2: The architecture of our proposed MMST-ViT." + ], + "image_footnote": [], + "bbox": [ + 189, + 93, + 777, + 396 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Capturing the Effect of Growing Season Weather Variations on Crop Growth. Previous studies only consider the meteorological data (or the remote sensing data) for crop yield predictions, overlooking the direct impact of growing season weather variations on crop growth. To capture such an impact, we aim to leverage both visual remote sensing and numerical meteorological data. In particular, the Multi-Head Attention (MHA) technique [50] is adopted to capture the meteorological effects on crop growth. However, how to perform multi-modal attention over visual remote sensing data and numerical meteorological data remains open.", + "bbox": [ + 75, + 426, + 472, + 593 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Lacking a Mechanism for Pre-training Multi-Modal Model. Deep neural networks (DNNs), especially Vision Transformer (ViT)-based models, are prone to overfitting, requiring appropriate pre-training to achieve satisfactory performance. Unfortunately, conventional pretraining techniques (e.g., SimCLR [9]) only marginally improve crop yield prediction performance as they consider the visual data only, ineffective for pre-training multi-modal models. How to pre-train the multi-modal model for satisfactory crop yield predictions is challenging to be addressed.", + "bbox": [ + 75, + 595, + 468, + 761 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Capturing the Impact of Climate Change on Crops. As reported by a prior study [39], the long-term climate change in the atmosphere would gradually decrease the crop yield on the ground. Some studies [28, 15] have demonstrated that taking the climate change effect into account can better crop yield prediction. But their designs overlook the remote sensing data, viewed as essential for precise agricultural tracking. So far, how to develop effective ways to capture the impact of long-term climate change on crop yields", + "bbox": [ + 75, + 763, + 470, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "is challenging and unanswered yet.", + "bbox": [ + 498, + 426, + 732, + 441 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.3. Our Proposed Approach", + "text_level": 1, + "bbox": [ + 498, + 449, + 725, + 465 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To tackle the aforementioned challenges, we develop the Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT) for predicting crop yields at the county level, by leveraging the remote sensing data and the short-term and long-term meteorological data.", + "bbox": [ + 496, + 472, + 890, + 547 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Model Overview. Our proposed MMST-ViT consists of three key components, i.e., Multi-Modal Transformer, Spatial Transformer, and Temporal Transformer, as shown in Figure 2. The Multi-Modal Transformer is designed to capture the impact of short-term meteorological variations on crop growth, by leveraging the satellite images (i.e., $\\mathbf{x}$ ) and the short-term meteorological parameters (i.e., $\\mathbf{y}_s$ ). The Spatial Transformer then utilizes the output of the Multi-Modal Transformer for learning the global spatial information of a county. Next, the Temporal Transformer combines the outputs of our Spatial Transformer and the long-term meteorological data (i.e., $\\mathbf{y}_l$ ) to capture both global temporal information and the impact of long-term climate change on crop yields. Finally, the output of our Temporal Transformer is used by a linear classifier for predicting the annual crop yields. The details of each component are provided below.", + "bbox": [ + 496, + 550, + 892, + 805 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Multi-Modal Transformer. Aiming to capture the direct impact of atmospheric weather variations on crop growth, the Multi-Modal Transformer consists of a visual backbone network and a multi-modal attention layer. The former extracts high-quality visual representations from satellite images for accurate agricultural tracking, while the lat", + "bbox": [ + 496, + 809, + 893, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "5777", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "ter captures the relationship between the visual representation and meteorological parameters, to understand the impact of meteorological parameters on crop growth. Let $f_{\\theta} \\colon (\\mathbb{R}^{T \\times G \\times H \\times W \\times C}, \\mathbb{R}^{T \\times G \\times N_1 \\times d_y}) \\to \\mathbb{R}^{T \\times G \\times d}$ be our Multi-Modal Transformer, with $\\pmb{\\theta}$ denoting the parameters for DNNs and $d$ representing the dimension for hidden vectors. Notably, all the hidden dimensions in this paper are set to the same size of $d$ . As such, the proposed Multi-Modal Transformer can be expressed as $f_{\\theta}(x, y_s) = v_m$ , where $x$ and $y_s$ are the Sentinel-2 images and the short-term meteorological data, respectively. $v_m \\in \\mathbb{R}^{T \\times G \\times d}$ is the output of our Multi-Modal Transformer.", + "bbox": [ + 75, + 90, + 472, + 271 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In this work, we utilize Pyramid Vision Transformer (PVT) [51] as the visual backbone network since it advances ResNet [19] and vanilla ViT [12] respectively by having the global receptive field and by enabling high-resolution feature maps. To capture the direct impact of meteorological parameters on crop growth during the growing season, a naive way is by concatenating visual and numerical representations extracted respectively from the Sentinel-2 images and the meteorological parameters. Unfortunately, our empirical results show that such a naive way cannot achieve satisfactory performance. Inspired by the recent success of multi-head attention mechanisms [50, 12, 40], we devise a novel Multi-Modal Multi-Head Attention (MM-MHA) mechanism to capture the impact of meteorological parameters on crop growth, mathematically expressed as", + "bbox": [ + 75, + 272, + 473, + 513 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {M M - M H A} (\\boldsymbol {Q}, \\boldsymbol {K}, \\boldsymbol {V}) = \\operatorname {S o f t m a x} (\\boldsymbol {Q} \\boldsymbol {K} ^ {T} / \\sqrt {d}) \\boldsymbol {V},\n$$\n", + "text_format": "latex", + "bbox": [ + 96, + 525, + 429, + 542 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {Q} = \\boldsymbol {W} _ {m} ^ {Q} \\cdot \\varphi_ {m} (\\boldsymbol {x}), \\boldsymbol {K} = \\boldsymbol {W} _ {m} ^ {K} \\cdot \\pi_ {m} (\\boldsymbol {y} _ {s}), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 122, + 546, + 468, + 564 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {V} = \\boldsymbol {W} _ {m} ^ {V} \\cdot \\pi_ {m} (\\boldsymbol {y} _ {s}).\n$$\n", + "text_format": "latex", + "bbox": [ + 194, + 566, + 333, + 585 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Here, $\\varphi_{m}(\\pmb{x})\\in \\mathbb{R}^{T\\times G\\times N_{p}\\times d}$ is the visual representation encoded by PVT, with $N_{p}$ indicating the number of image patches. $\\pi_m(\\pmb {y}_s)\\in \\mathbb{R}^{T\\times G\\times N_1\\times d}$ is the meteorological parameters after the linear projection. Notably, $\\pmb{W}_{m}^{Q},\\pmb{W}_{m}^{K}$ , and $\\pmb{W}_{m}^{V}$ are learnable projection matrices, similar to those in prior studies [50, 40]. To our knowledge, this is the first attempt at developing a multi-modal multi-attention approach for leveraging both visual remote sensing data and numerical meteorological data.", + "bbox": [ + 75, + 597, + 468, + 733 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "However, ViT-based models are highly sensitive to overfitting, calling for pre-training with millions of visual data [12]. Meanwhile, real-world crop yield prediction usually lacks sufficient crop data for pre-training. Worse still, capturing the impact of short-term weather conditions on crops requires considering both the visual and the numerical data simultaneously. Although self-supervised learning techniques [9, 5, 18] have recently been developed for pretraining DNNs, they cannot tackle the aforementioned issue at the same time. For example, SimCLR [9] fails to address the multi-modal data issue.", + "bbox": [ + 75, + 734, + 470, + 900 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/7b2afaaa406c86d2319c255b874242f1998dcb63b74f4614d577a37e2003a470.jpg", + "image_caption": [ + "Figure 3: Multi-modal self-supervised learning." + ], + "image_footnote": [], + "bbox": [ + 504, + 95, + 893, + 335 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Here, we propose a novel multi-modal self-supervised learning for pre-training our Multi-Modal Transformer without human supervision, which is inspired by SimCLR, but having two differences. First, we utilize the PVT instead of convolutional neural networks (CNNs) as the backbone network since PVT advances CNNs by having a global receptive field [51]. Second, we replace the Multi-Layer Perceptron (MLP) layer in SimCLR with our proposed multimodal self-attention layer (i.e., Eq. (1)) for simultaneously tackling visual and numerical data. Figure 3 illustrates its architecture. Given a satellite image $\\pmb{x}^m$ (or $\\pmb{x}^n$ ), we perform the data augmentation to get its two augmented images, and then feed them to the PVT to get two sets of visual representations. After that, we use our proposed MM-MHA (i.e., Eq. (1)) to perform multi-modal attention between the visual representations and the corresponding short-term parameters $\\pmb{y}_s^m$ (or $\\pmb{y}_s^n$ ), arriving at two sets of output sequences. Here, we regard two sets of output sequences out of a given satellite image (e.g., $\\pmb{x}^m$ ) as the positive pair. Meanwhile, two sets of output sequences from different satellite images (e.g., $\\pmb{x}^m$ and $\\pmb{x}^n$ ) are regarded as the negative pair. Similar to vanilla ViT [12], the head of output sequences (i.e., the classification token) is taken as the output of our Multi-Modal Transformer, i.e., the hidden vector $\\pmb{v}_m$ . As such, our multi-modal contrastive loss is defined as,", + "bbox": [ + 496, + 377, + 893, + 770 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\ell (i, j) = - \\log \\frac {\\exp (\\operatorname {s i m} \\left(\\boldsymbol {v} _ {m} ^ {i} , \\boldsymbol {v} _ {m} ^ {j}\\right) / \\tau)}{\\sum_ {i \\neq k , k = 1 , \\dots , 2 B} \\exp (\\operatorname {s i m} \\left(\\boldsymbol {v} _ {m} ^ {i} , \\boldsymbol {v} _ {m} ^ {k}\\right) / \\tau)},\n$$\n", + "text_format": "latex", + "bbox": [ + 513, + 776, + 875, + 813 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {c l}} = \\frac {1}{2 B} \\sum_ {k = 1} ^ {B} [ \\ell (k, k + B) + \\ell (k + B, k) ], \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 555, + 816, + 890, + 869 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $B = T \\times G$ . Here, $\\pmb{v}_m^i$ and $\\pmb{v}_m^j$ are the positive pair, and $\\tau$ is the temperature parameter. Intuitively, our", + "bbox": [ + 496, + 869, + 892, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "5778", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Eq. (2) encourages two hidden vectors from the same satellite image (i.e., representing the same region) to be similar, and two hidden vectors from different satellite images (i.e., representing different regions) to be dissimilar. As such, we can pre-train our Multi-Modal Transformer to capture the impact of short-term meteorological parameters on crop growth without labor-intensive human supervision.", + "bbox": [ + 75, + 90, + 468, + 196 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Spatial Transformer. Recall that the Sentinel-2 Imagery dataset of a county is partitioned into multiple fine-grained grids for precise agricultural tracking. To learn spatial dependency among those grids, we propose a Spatial Transformer $g_{\\phi} : \\mathbb{R}^{T \\times G \\times d} \\to \\mathbb{R}^{T \\times d}$ , whose purpose is to capture the global spatial representations for counties. The design of our Spatial Transformer is inspired by the vanilla ViT [12] but with a flexible number of positional embeddings. It is used to tackle the scenario that the number of grids varies among counties as it depends on county sizes. To learn global spatial information for counties, the Spatial Transformer prepends a learnable classification token $v_{m}^{\\mathrm{cls}} \\in \\mathbb{R}^{T \\times 1 \\times d}$ , arriving at", + "bbox": [ + 75, + 199, + 470, + 397 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\varphi_ {s} \\left(\\boldsymbol {v} _ {m}\\right) = \\left[ \\boldsymbol {v} _ {m} ^ {\\text {c l s}}; \\boldsymbol {v} _ {m} ^ {1}; \\boldsymbol {v} _ {m} ^ {2}; \\dots ; \\boldsymbol {v} _ {m} ^ {G} \\right] + \\mathbf {E} _ {\\text {p o s}}, \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 120, + 401, + 468, + 420 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $\\mathbf{E}_{\\mathrm{pos}} \\in \\mathbb{R}^{T \\times (G + 1) \\times d}$ is the flexible positional embeddings. We propose a Spatial Multi-Head Attention (S-MHA) to learn spatial dependency among grids. Mathematically,", + "bbox": [ + 75, + 426, + 468, + 489 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {S - M H A} (\\boldsymbol {Q}, \\boldsymbol {K}, \\boldsymbol {V}) = \\operatorname {S o f t m a x} (\\boldsymbol {Q} \\boldsymbol {K} ^ {T} / \\sqrt {d}) \\boldsymbol {V},\n$$\n", + "text_format": "latex", + "bbox": [ + 114, + 494, + 429, + 513 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {Q} = \\boldsymbol {W} _ {s} ^ {Q} \\cdot \\varphi_ {s} (\\boldsymbol {v} _ {m}), \\boldsymbol {K} = \\boldsymbol {W} _ {s} ^ {K} \\cdot \\varphi_ {s} (\\boldsymbol {v} _ {m}), \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 129, + 516, + 468, + 534 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {V} = \\boldsymbol {W} _ {s} ^ {V} \\cdot \\varphi_ {s} (\\boldsymbol {v} _ {m}).\n$$\n", + "text_format": "latex", + "bbox": [ + 210, + 537, + 351, + 554 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Here, $\\boldsymbol{W}_s^Q, \\boldsymbol{W}_s^K, \\boldsymbol{W}_s^V$ are three learnable matrices, similar to those given in Eq. (1). Finally, we regard the head of output sequences as global spatial representations of counties. That is, we have $g_{\\phi}(\\boldsymbol{v}_m) = \\boldsymbol{v}_s$ , with $\\boldsymbol{v}_s \\in \\mathbb{R}^{T \\times d}$ signifying the hidden vector that incorporates global spatial information.", + "bbox": [ + 75, + 561, + 468, + 652 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Temporal Transformer. The Temporal Transformer possesses two goals. The first goal aims to learn temporal dependency among the hidden vectors $\\boldsymbol{v}_s$ , i.e., the outputs of our Spatial Transformer. The second goal is to capture the effect of long-term climate change on crop yields. To achieve the first goal, we add a classification token $\\boldsymbol{v}_s^{\\mathrm{cls}}$ for learning the global temporal representation, i.e.,", + "bbox": [ + 75, + 656, + 468, + 762 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\varphi_ {t} \\left(\\boldsymbol {v} _ {s}\\right) = \\left[ \\boldsymbol {v} _ {s} ^ {\\text {c l s}}; \\boldsymbol {v} _ {s} ^ {1}; \\boldsymbol {v} _ {s} ^ {2}; \\dots ; \\boldsymbol {v} _ {s} ^ {T} \\right] + \\mathbf {E} _ {\\text {t m p}}, \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 127, + 768, + 468, + 786 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $\\mathbf{E}_{\\mathrm{tmp}} \\in \\mathbb{R}^{(T + 1) \\times d}$ is the temporal embedding, similar to the positional embeddings $\\mathbf{E}_{\\mathrm{pos}}$ expressed in Eq. (3). The novel Temporal Multi-Head Attention (T-MHA) is also devised to capture the impact of long-term historical meteorological parameters on crop yields. Its key idea is to incorporate a relative meteorological bias into each head for similarity computation, motivated by prior studies [6, 38, 33].", + "bbox": [ + 75, + 794, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Mathematically, our T-MHA can be expressed by", + "bbox": [ + 500, + 90, + 826, + 106 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\operatorname {T} - \\operatorname {M H A} (\\boldsymbol {Q}, \\boldsymbol {K}, \\boldsymbol {V}) = \\operatorname {S o f t m a x} (\\boldsymbol {Q} \\boldsymbol {K} ^ {\\boldsymbol {T}} / \\sqrt {d} + \\pi_ {t} (\\boldsymbol {y} _ {l})) \\boldsymbol {V}, \\\\ \\boldsymbol {Q} = \\boldsymbol {W} _ {t} ^ {Q} \\cdot \\varphi_ {t} (\\boldsymbol {v} _ {s}), \\boldsymbol {K} = \\boldsymbol {W} _ {t} ^ {K} \\cdot \\varphi_ {t} (\\boldsymbol {v} _ {s}), \\\\ \\boldsymbol {V} = \\boldsymbol {W} _ {t} ^ {V} \\cdot \\varphi_ {t} (\\boldsymbol {v} _ {s}). \\tag {6} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 506, + 118, + 888, + 191 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Here, $\\pmb{y}_l$ represents the long-term meteorological parameters, and $\\pi_t(\\cdot)$ is a linear projection layer. Similarly, $\\pmb{W}_t^Q$ , $\\pmb{W}_t^K$ , $\\pmb{W}_t^V$ are three learnable matrices. In summary, our Temporal Transformer $h_\\psi : (\\mathbb{R}^{T \\times d}, \\mathbb{R}^{T \\times N_2 \\times d_y}) \\to \\mathbb{R}^d$ can be defined as $h_\\psi(\\pmb{v}_s, \\pmb{y}_l) = \\pmb{v}_t$ , with $\\pmb{v}_t \\in \\mathbb{R}^d$ being the hidden vector that incorporates both global temporal information and the impact of climate change on crops simultaneously.", + "bbox": [ + 496, + 191, + 890, + 311 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Finally, the hidden vector $\\pmb{v}_t$ is fed into a linear classifier for crop yield predictions, i.e., $\\hat{\\pmb{z}} = \\pmb{W}^T\\pmb{v}_t + \\pmb{b}$ , with $\\pmb{W}$ and $\\pmb{b}$ respectively denoting the weights and the bias for the classifier, and $\\hat{\\pmb{z}} \\in \\mathbb{R}^{d_z}$ indicating the crop yield prediction.", + "bbox": [ + 496, + 313, + 890, + 375 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 500, + 387, + 632, + 404 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We conduct experiments for the county-level crop yield predictions across four U.S. states, i.e., Mississippi (MS), Louisiana (LA), Iowa (IA), and Illinois (IL). Four types of crops, i.e., corn, cotton, soybean, and winter wheat, are taken into account for performance evaluation.", + "bbox": [ + 496, + 412, + 890, + 489 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Experimental Settings", + "text_level": 1, + "bbox": [ + 500, + 498, + 705, + 513 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Datasets. We utilize the Sentinel-2 imagery and the daily HRRR data datasets during the growing season respectively as the remote sensing data and the short-term meteorological data. Meanwhile, the monthly HRRR data from the previous three years are used as the long-term meteorological parameters.", + "bbox": [ + 496, + 525, + 890, + 616 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Compared Approaches. We compare our proposed MMST-ViT to three DL-based approaches, with one, i.e., ConvLSTM [43], developed for spatial-temporal prediction, and the other two, i.e., CNN-RNN [28] and GNN-RNN [15], developed for crop yield predictions. Minor rectifications are made to them so that they can admit the Sentinel-2 imagery and HRRR datasets as their inputs. Other hyperparameters, unless specified otherwise, are set to the values as those reported in their original studies.", + "bbox": [ + 496, + 619, + 890, + 756 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Metrics. We take three performance metrics, i.e., Root Mean Square Error (RMSE), R-squared $(\\mathbf{R}^2)$ , and Pearson Correlation Coefficient (Corr), for comparative evaluation. Notably, a lower value of RMSE or a higher value of $\\mathbf{R}^2$ (or Corr) indicates better performance.", + "bbox": [ + 496, + 760, + 890, + 835 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Model Size. Our proposed MMST-ViT builds on the top of Vision Transformer (ViT) [12]. Similar to ViT, it consists of a stack of Transformer blocks [50], where each Transformer block includes a Multi-Head Attention (MHA) block and", + "bbox": [ + 496, + 839, + 893, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "5779", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/695b3b38b8049bb50d0073051c0e8796514033e863b860b371021d11ba54fc85.jpg", + "table_caption": [ + "Table 2: Model details used in our study" + ], + "table_footnote": [], + "table_body": "
ModelLayerHidden SizeHeadMLP SizeOthers
Multi-Modal TransformerPVT-T/4{2, 2, 2, 2}{64, 128, 320, 512}{1, 2, 5, 8}{512, 1024, 1280, 2048}SR Ratios = {8, 4, 2, 1}
MM-MHA251282048Context Size = 9
Spatial TransformerS-MHA451232048-
Temporal TransformerT-MHA451232048Context Size = 9
", + "bbox": [ + 89, + 112, + 879, + 178 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/3bbf08fddb1f17bb1385ad70121a6dc2081400a0d3ddb47949288bdc45bb2fd9.jpg", + "table_caption": [ + "Table 3: Overall comparative crop yield predictions for 2021, with the best results shown in bold. Cotton yields are measured in pounds per acre (LB/AC), whereas other crop yields are measured in bushels per acre (BU/AC)" + ], + "table_footnote": [], + "table_body": "
MethodCornCottonSoybeanWinter Wheat
RMSE (↓)R2(↑)Corr (↑)RMSE (↓)R2(↑)Corr (↑)RMSE (↓)R2(↑)Corr (↑)RMSE (↓)R2(↑)Corr (↑)
ConvLSTM18.60.6110.78265.40.7150.8467.20.6160.7857.40.5110.715
CNN-RNN14.60.7050.83969.50.6530.8085.80.7030.8397.50.6140.783
GNN-RNN14.20.7300.85458.50.6470.8045.40.7480.8656.00.6210.788
Ours10.50.8110.90042.40.7900.8893.90.8430.9184.60.7850.886
", + "bbox": [ + 91, + 220, + 879, + 311 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "an MLP block, and both of which incorporate the LayerNorm [4] for normalization. Table 2 presents the details of model sizes used in our experiments. Note that \"PVT-T/4\" refers to the PVT-Tiny model with a patch size of 4, and \"SR Ratios\" represents the spatial reduction ratio in PVT. Following the original PVT [51], we divide the PVT backbone into four stages and report the corresponding model sizes at each stage in the second row of Table 2. The other transformers are single-stage, similar to the vanilla ViT [12]. Notably, \"Context Size\" represents the number of meteorological parameters used in our study.", + "bbox": [ + 73, + 327, + 470, + 492 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Hyperparameters. Our model is pre-trained for 200 epochs using AdamW [35] with $\\beta_{1} = 0.9$ , $\\beta_{2} = 0.95$ , a weight decay of 0.05, and a cosine decay schedule [34] with an initial learning rate of $1e - 4$ , and warmup epochs of 20. To perform data augmentation for pre-training, various techniques such as random cropping, random horizontal flipping, random Gaussian blur, and color jittering are employed. These techniques are similar to those used in SimCLR [9]. After pre-training, we fine-tune our proposed MMST-ViT for 100 epochs using AdamW with $\\beta_{1} = 0.9$ , $\\beta_{2} = 0.999$ , a cosine decay schedule with an initial learning rate of $1e - 3$ , and warmup epochs of 5.", + "bbox": [ + 75, + 500, + 468, + 680 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.2. Comparative Performance Evaluation", + "text_level": 1, + "bbox": [ + 76, + 693, + 405, + 709 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We conduct experiments for predicting 2021 crop yields at the county level across four aforementioned U.S. states, with prediction performance measured by the three metrics of RMSE, $\\mathbf{R}^2$ , and Corr.", + "bbox": [ + 75, + 717, + 468, + 777 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 3 lists the comparative performance results of our MMST-ViT and its three counterparts, i.e., ConvLSTM, CNN-RNN, and GNN-RNN. Four observations are obtained from the table. First, our approach achieves the best performance under all metrics. In particular, for the soybean yield prediction, our approach achieves the lowest RMSE of 3.9 and the highest $R^2$ (or Corr) of 0.843 (or 0.918). With the lowest RMSE value, our predicted soybean", + "bbox": [ + 75, + 779, + 470, + 901 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "yields are the closest to the actual amounts. In addition, the highest $\\mathbb{R}^2$ and Corr values demonstrate that our predicted soybean yields are best correlated to actual figures. Second, our approach significantly outperforms ConvLSTM, with its RMSE values always lower than those of ConvLSTM markedly, ranging from 2.8 (for winter wheat) to 23.0 (for cotton). The reason is that ConvLSTM overlooks the impact of meteorological parameters on crop growth. Third, CNN-RNN underperforms our approach by 4.1 (for corn), by 27.1 (for cotton), by 1.9 (for soybean), and by 2.9 (for winter wheat), in terms of RMSE, though both models take into account the effect of long-term climate change on crop yields. Because CNN-RNN cannot model the spatial dependency among neighborhood regions. Fourth, MMST-ViT outperforms the most recent state-of-the-art (i.e., GNN-RNN) measurably. Specifically, our RMSE value is lower by 16.1 for cotton, whereas our $\\mathbb{R}^2$ and Corr values are better respectively by 0.165 and 0.098 for winter wheat. These results are contributed by leveraging both visual remote sensing and numerical meteorological data in our model, while GNN-RNN only considers the meteorological data.", + "bbox": [ + 496, + 327, + 893, + 645 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.3. Visualizing Crop Yield Prediction Errors", + "text_level": 1, + "bbox": [ + 498, + 662, + 849, + 679 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In this section, we conduct experiments to visualize crop yield prediction errors across four U.S. states: Mississippi (MS), Louisiana (LA), Iowa (IA), and Illinois (IL). We use the same experimental settings as those stated in Section 5.2. Figure 4 shows the absolute prediction errors for soybean across counties/parishes in the four states, with navy blue and light blue respectively indicating the high and low absolute errors. Our MMST-ViT model is highly effective in predicting crop yields, with the absolute prediction errors of $57.2\\%$ counties below 3 BU/AC. Furthermore, we discover that $95.1\\%$ of counties in MS, $92.5\\%$ of parishes in LA, $86.8\\%$ of counties in IA, and $91.0\\%$ of counties in IL achieve decent absolute prediction errors (i.e., $\\leq 6$ BU/AC). These empirical findings validate the robustness of MMST-", + "bbox": [ + 496, + 689, + 893, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "5780", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1d956d0f443ff02eb3c3de0c0df4b4f9e29d5c5b3ef47f1fc674f60ffed88d87.jpg", + "image_caption": [ + "(a) Mississippi (MS)" + ], + "image_footnote": [], + "bbox": [ + 116, + 88, + 272, + 200 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/a20a4814dbeb98971c8420c01c0b1476f491d2a264d5b104b5965ccda583e431.jpg", + "image_caption": [ + "(b) Louisiana (LA)", + "Figure 4: Illustration of absolute prediction errors for soybean across four U.S. states. Note that a county/parish with $< 0$ indicates its soybean yield data is unavailable." + ], + "image_footnote": [], + "bbox": [ + 297, + 88, + 464, + 200 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/9f48bfe618aec09d00e9ca2aa12c65b24bc4068d39246a24a9a52780825238bd.jpg", + "image_caption": [ + "(c) Iowa (IA)" + ], + "image_footnote": [], + "bbox": [ + 478, + 89, + 661, + 200 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/3471bae2b18dc576cc4955b1861ea12ba673c9f35f7db00c4b7c95bfd467e959.jpg", + "image_caption": [ + "(d) Illinois (IL)" + ], + "image_footnote": [], + "bbox": [ + 710, + 89, + 861, + 200 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "ViT across various geographic locations.", + "bbox": [ + 76, + 280, + 346, + 295 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4. Performance of One Year Ahead Predictions", + "text_level": 1, + "bbox": [ + 76, + 303, + 454, + 318 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In practice, predicting crop yields well in advance of harvest, can provide valuable information for farmers, agribusinesses, and governments in their agricultural planning and decision-making processes. This information can be used to elevate agricultural resilience and sustainability, make informed financial decisions, and support global food security [23]. A prior study [15] simulated the early prediction scenario by masking partial inputs, successfully making predictions several months before harvest. In this study, we attempt a step further by making crop yield predictions one year before the harvest. In particular, we leverage remote sensing and short-term meteorological data during the growing season in the current year to predict crop yields in the next year. For example, the Sentinel-2 imagery and daily HRRR data during the growing season in 2020 are utilized as remote sensing data and the short-term meteorological data for predicting crop yields in 2021.", + "bbox": [ + 75, + 327, + 468, + 583 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Figure 5 illustrates the experimental results. It is observed that our MMST-ViT outperforms three baseline models, i.e., ConvLSTM, CNN-RNN, and GNN-RNN, for the predictions of one year ahead. Among all crops, MMST-ViT achieves the lowest RMSE values ranging from 4.7 (for soybean) to 50.2 (for cotton), the highest $\\mathbb{R}^2$ values ranging from 0.711 (for winter wheat) to 0.792 (for soybean), and the highest Corr values ranging from 0.843 (for winter wheat) to 0.890 (for soybean). Additionally, compared to its in-season prediction results (see the 6th row of Table 3), the one year ahead prediction outcomes of our approach are just slightly inferior, degraded respectively by $8.6\\%$ , of $15.5\\%$ , of $17.0\\%$ , and of $14.6\\%$ in terms of RMSE for corn, cotton, soybean, and winter wheat. The empirical results confirm the robustness of MMST-ViT.", + "bbox": [ + 75, + 584, + 468, + 809 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Interestingly, we also observe that the prediction results for the cotton have a high RMSE value but not a low $\\mathbb{R}^2$ (or Corr) value. This is because the cotton yield is measured by pounds per acre (LB/AC), with a high standard deviation value of 250.1, while other crop yields are measured by bushels per acre (BU/AC), with low standard deviation val", + "bbox": [ + 75, + 810, + 468, + 900 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/e2267f048c2c24bb76f7c29b4c13071e3d66313e28e71cad3dca2126e431ca69.jpg", + "table_caption": [ + "Table 4: Ablation studies for different components, with five scenarios considered and the last row listing the results of MMST-ViT" + ], + "table_footnote": [], + "table_body": "
ComponentCornSoybean
RMSE (↓)Corr (↑)RMSE (↓)Corr (↑)
Temporal Transformerw/o long-term14.50.8436.20.850
w/o T-MHA15.70.8205.60.839
Spatial Transformerw/o S-MHA13.50.8565.60.849
Multi-Modal Transformerw/o short-term13.60.8396.10.845
w/o image15.20.8096.80.822
MMST-ViT-10.50.9003.90.918
", + "bbox": [ + 503, + 330, + 888, + 463 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "ues (e.g., 11.8 for soybean). In scenarios with high variance data, the RMSE value may worsen due to larger residuals, while the $\\mathbf{R}^2$ value improves due to the increased proportion of explained variance.", + "bbox": [ + 498, + 481, + 890, + 542 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.5. Ablation Studies", + "text_level": 1, + "bbox": [ + 500, + 553, + 663, + 568 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Key Components. We next conduct experiments to show how each key component in our MMST-ViT affects prediction performance. Table 4 lists the results of our ablation studies under five different scenarios, with one shown in a row. Here, \"w/o long-term\" indicates masking the long-term meteorological data, and \"w/o T-MHA\" represents the absence of our Temporal Transformer and instead resorting to the average pooling to obtain the global temporal representation. Similarly, \"w/o S-MHA\" denotes utilizing the average pooling to obtain the global spatial representation. The scenarios of \"w/o short-term\" and \"w/o image\" represent respectively masking the short-term meteorological data and the remote sensing data from the Multi-Modal Transformer. Note that masking either data makes our model unable to conduct MM-MHA, following Eq. (1). The results of our complete MMST-ViT outcomes are shown in the last row of Table 4.", + "bbox": [ + 496, + 582, + 890, + 838 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Three observations can be made from Table 4. First, the long-term meteorological data degrades the Corr value by 0.057 (or 0.068) for corn (or soybean). This validates that crop yield prediction accuracy can benefit from histori", + "bbox": [ + 496, + 839, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "5781", + "bbox": [ + 482, + 945, + 513, + 955 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/5abb09dbcdc3fcf16fb337d1991bb01de120a1221fa2d52f42cf2d9c51aacbfe.jpg", + "image_caption": [ + "(a) RMSE" + ], + "image_footnote": [], + "bbox": [ + 81, + 89, + 326, + 227 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/301bb5ac0757881f7c7e642ca0cefbee658c57c8b9bc4ef9cd5d4f8be09de8f1.jpg", + "image_caption": [ + "(b) $\\mathbf{R}^2$", + "Figure 5: Illustration of the performance for predictions of one year ahead under (a) RMSE, (b) $\\mathbb{R}^2$ , and (c) Corr, with the cotton yield measured by LB/AC and other crop yields measured by BU/AC." + ], + "image_footnote": [], + "bbox": [ + 341, + 89, + 588, + 229 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/2c95e90e2b35bedf7a8f2b2f39fc5e00c6a9db14f757b8797ea9ee5e12ac9fe2.jpg", + "image_caption": [ + "(c) Corr" + ], + "image_footnote": [], + "bbox": [ + 606, + 90, + 851, + 229 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "ical meteorological data, which dictates long-term climate change. Second, the absence of either the Temporal Transformer or the Spatial Transformer lowers the Corr value by 0.080 (for corn) and by 0.069 (for soybean), respectively. Third, unable to conduct MM-MHA as the result of masking the short-term meteorological data or the satellite images degrades prediction performance greatly. For example, masking the short-term meteorological data (or satellite images) causes the Corr value degradation by 0.096 (or 0.073) for soybean. This statistical evidence exhibits the importance of our Multi-Modal Transformer for capturing the impact of meteorological parameters on crop growth.", + "bbox": [ + 75, + 301, + 470, + 483 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Pre-training Techniques. We conduct experiments to explore the impact of our proposed multi-modal self-supervised pre-training, i.e., Eq. (2), on the crop yield prediction. We consider three scenarios, i.e., MMST-ViT without pre-training, with the pre-training technique described in SimCLR [9], and with our multi-modal pre-training. Table 5 presents the prediction performance outcomes. The table reveals that our MMST-ViT (w/ our multi-modal pretraining) significantly outperforms its counterpart (w/o pretraining), exhibiting a lower RMSE value by 2.7 (or 1.2) and a larger Corr value by 0.043 (or 0.043) for corn (or soybean), due to two reasons. First, Vision Transformer (ViT)-based models are prone to overfitting [12], but our multi-modal self-supervised learning can significantly mitigate this issue by leveraging both visual remote sensing data and numerical meteorological data for pre-training. Second, our multi-modal self-supervised pre-training may can capture the impact of meteorological parameters on the crops. In contrast, pre-training our MMST-ViT with the SimCLR technique only achieves marginal performance improvement (compared to the one w/o pre-training), achieving the Corr improvement of 0.001 (0.875 v.s. 0.876) for soybean. This is because the SimCLR technique fails to leverage numerical meteorological parameters for pre-training. These empirical results validate the necessity and importance of our proposed multi-modal pre-training for accurate crop yield predictions.", + "bbox": [ + 75, + 493, + 470, + 901 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/c106bbd7d829d05f4f6604cda5e8a849aa17c19b8ce8dd7edc5e153c82b838e4.jpg", + "table_caption": [ + "Table 5: Ablation studies for different pre-training techniques, with three scenarios considered" + ], + "table_footnote": [], + "table_body": "
MethodCornSoybean
RMSE (↓)Corr (↑)RMSE (↓)Corr (↑)
w/o pretraining13.20.8575.10.875
w/ SimCLR12.90.8574.90.876
w/ multi-modal pretraining10.50.9003.90.918
", + "bbox": [ + 503, + 337, + 888, + 411 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 426, + 617, + 441 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This paper has proposed the Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), a climate change-aware deep learning approach for predicting crop yields at the county level across the United States. MMST-ViT comprises three key components of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer. Three innovative Multi-Head Attention (MHA) mechanisms are introduced, one for each component. As a result, our MMST-ViT can leverage both the visual remote sensing data and the numerical meteorological data for capturing the impact of short-term growing season weather variations and long-term climate change on crop yields. Additionally, a novel multi-modal contrastive learning technique has been developed, able to effectively pre-train our model without the need of human supervision. We have conducted extensive experiments on $200+$ counties/parishes located in 4 U.S. states, with the results demonstrating that our proposed MMST-ViT substantially outperforms its state-of-the-art counterparts consistently under three performance metrics of interest.", + "bbox": [ + 496, + 455, + 890, + 757 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgments", + "text_level": 1, + "bbox": [ + 500, + 781, + 658, + 797 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work was supported in part by NSF under Grants 2019511, 2146447, and in part by the BoRSF under Grants LEQSF(2019-22)-RD-A-21 and LEQSF(2021-22)-RD-D-07. Any opinion and findings expressed in the paper are those of the authors and do not necessarily reflect the view of funding agencies.", + "bbox": [ + 496, + 809, + 890, + 901 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "5782", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Faezeh Akhavizadegan, Javad Ansarifar, Lizhi Wang, Isaiah Huber, and Sotirios V Archontoulis. A time-dependent parameter estimation framework for crop modeling. Scientific reports, 2021.", + "[2] Javad Ansarifar, Lizhi Wang, and Sotirios V Archontoulis. An interaction regression model for crop yield prediction. Scientific reports, 2021.", + "[3] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In International Conference on Computer Vision (ICCV), 2021.", + "[4] Jimmy Lei Ba, Jamie Ryan Kiros, and Geoffrey E Hinton. Layer normalization. arXiv preprint arXiv:1607.06450, 2016.", + "[5] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. Beit: BERT pre-training of image transformers. In International Conference on Learning Representations (ICLR), 2022.", + "[6] Hangbo Bao, Li Dong, Furu Wei, Wenhui Wang, Nan Yang, Xiaodong Liu, Yu Wang, Jianfeng Gao, Songhao Piao, Ming Zhou, and Hsiao-Wuen Hon. Unilmv2: Pseudo-masked language models for unified language model pre-training. In International Conference on Machine Learning (ICML), 2020.", + "[7] Mathilde Caron, Hugo Touvron, Ishan Misra, Hervé Jégou, Julien Mairal, Piotr Bojanowski, and Armand Joulin. Emerging properties in self-supervised vision transformers. In International Conference on Computer Vision (ICCV), 2021.", + "[8] Liyan Chen, Weihan Wang, and Philippos Mordohai. Learning the distribution of errors in stereo matching for joint disparity and uncertainty estimation. In Computer Vision and Pattern Recognition (CVPR), 2023.", + "[9] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey E. Hinton. A simple framework for contrastive learning of visual representations. In International Conference on Machine Learning (ICML), 2020.", + "[10] Minghan Cheng, Xiyun Jiao, Lei Shi, Josep Penuelas, Lalit Kumar, Chenwei Nie, Tianao Wu, Kaihua Liu, Wenbin Wu, and Xiuliang Jin. High-resolution crop yield and water productivity dataset generated using random forest and remote sensing. Scientific Data, 2022.", + "[11] Karine Chenu, John Roy Porter, Pierre Martre, Bruno Basso, Scott Cameron Chapman, Frank Ewert, Marco Bindi, and Senthold Asseng. Contribution of crop models to adaptation in wheat. Trends in plant science, 2017.", + "[12] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations (ICLR), 2021.", + "[13] Nicola Falco, Haruko M Wainwright, Baptiste Dafflon, Craig Ulrich, Florian Soom, John E Peterson, James Bentley Brown, Karl B Schaettle, Malcolm Williamson, Jackson D Cothren, et al. Influence of soil heterogeneity on soybean plant development and crop yield evaluated using time-series" + ], + "bbox": [ + 78, + 114, + 468, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "of uav and ground-based geophysical imagery. Scientific reports, 2021.", + "[14] Haoqi Fan, Bo Xiong, Karttikeya Mangalam, Yanghao Li, Zhicheng Yan, Jitendra Malik, and Christoph Feichtenhofer. Multiscale vision transformers. In International Conference on Computer Vision (ICCV), 2021.", + "[15] Joshua Fan, Junwen Bai, Zhiyun Li, Ariel Ortiz-Bobea, and Carla P. Gomes. A GNN-RNN approach for harnessing geospatial and temporal information: Application to crop yield prediction. In AAAI, 2022.", + "[16] Niketa Gandhi, Owaiz Petkar, and Leisa J Armstrong. Rice crop yield prediction using artificial neural networks. In 2016 IEEE Technological Innovations in ICT for Agriculture and Rural Development (TIAR), 2016.", + "[17] Vivien Sainte Fare Garnot and Loic Landrieu. Panoptic segmentation of satellite image time series with convolutional temporal attention networks. In International Conference on Computer Vision (ICCV), 2021.", + "[18] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross B. Girshick. Masked autoencoders are scalable vision learners. In Conference on Computer Vision and Pattern Recognition (CVPR), 2022.", + "[19] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Conference on Computer Vision and Pattern Recognition (CVPR), 2016.", + "[20] Yi He, Fudong Lin, Xu Yuan, and Nian-Feng Tzeng. Interpretable minority synthesis for imbalanced classification. In IJCAI, 2021.", + "[21] Byeongho Heo, Sangdoo Yun, Dongyoon Han, Sanghyuk Chun, Junsuk Choe, and Seong Joon Oh. Rethinking spatial dimensions of vision transformers. In International Conference on Computer Vision (ICCV), 2021.", + "[22] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 1997.", + "[23] Takeshi Horie, Masaharu Yajima, and Hiroshi Nakagawa. Yield forecasting. Agricultural systems, 1992.", + "[24] HRRR. The high-resolution rapid refresh (hrrr), 2022.", + "[25] James W Jones, John M Antle, Bruno Basso, Kenneth J Boote, Richard T Conant, Ian Foster, H Charles J Godfray, Mario Herrero, Richard E Howitt, Sander Janssen, et al. Toward a new generation of agricultural system data, models, and knowledge products: State of agricultural systems science. Agricultural systems, 2017.", + "[26] Saeed Khaki, Hieu Pham, and Lizhi Wang. Simultaneous corn and soybean yield prediction from remote sensing data using deep transfer learning. Scientific Reports, 2021.", + "[27] Saeed Khaki and Lizhi Wang. Crop yield prediction using deep neural networks. Frontiers in plant science, 2019.", + "[28] Saeed Khaki, Lizhi Wang, and Sotirios V Archontoulis. A cnn-rnn framework for crop yield prediction. Frontiers in Plant Science, 2020.", + "[29] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E. Hinton. Imagenet classification with deep convolutional neural networks. In Neural Information Processing Systems (NeurIPS), 2012.", + "[30] Zhengfeng Lai, Sol Vesdapunt, Ning Zhou, Jun Wu, Cong Phuoc Huynh, Xuelu Li, Kah Kuen Fu, and Chen-Nee" + ], + "bbox": [ + 503, + 92, + 890, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "5783", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Chuah. Padclip: Pseudo-labeling with adaptive debiasing in clip for unsupervised domain adaptation. In International Conference on Computer Vision (ICCV), 2023.", + "[31] Yanghao Li, Chao-Yuan Wu, Haoqi Fan, Karttikeya Mangalam, Bo Xiong, Jitendra Malik, and Christoph Feichtenhofer. Mvitv2: Improved multiscale vision transformers for classification and detection. In Computer Vision and Pattern Recognition (CVPR), 2022.", + "[32] Fudong Lin, Xu Yuan, Lu Peng, and Nian-Feng Tzeng. Cascade variational auto-encoder for hierarchical disentangle-. ment. In Conference on Information & Knowledge Management (CIKM), 2022.", + "[33] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In International Conference on Computer Vision (ICCV), 2021.", + "[34] Ilya Loshchilov and Frank Hutter. SGDR: stochastic gradient descent with warm restarts. In International Conference on Learning Representations (ICLR), 2017.", + "[35] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In International Conference on Learning Representations, 2019.", + "[36] Spyridon Mourtzinis, Paul D Esker, James E Specht, and Shawn P Conley. Advancing agricultural research using machine learning algorithms. Scientific reports, 2021.", + "[37] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, Gretchen Krueger, and Ilya Sutskever. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning (ICML), 2021.", + "[38] Colin Raffel, Noam Shazeer, Adam Roberts, Katherine Lee, Sharan Narang, Michael Matena, Yanqi Zhou, Wei Li, and Peter J Liu. Exploring the limits of transfer learning with a unified text-to-text transformer. The Journal of Machine Learning Research, 2020.", + "[39] David Rolnick, Priya L Donti, Lynn H Kaack, Kelly Kochanski, Alexandre Lacoste, Kris Sankaran, Andrew Slavin Ross, Nikola Milojevic-Dupont, Natasha Jaques, Anna Waldman-Brown, et al. Tackling climate change with machine learning. ACM Computing Surveys (CSUR), 2022.", + "[40] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Conference on Computer Vision and Pattern Recognition (CVPR), 2022.", + "[41] Sentinel-Hub. Sentinel hub process api, 2022.", + "[42] Mohsen Shahhosseini, Guiping Hu, Isaiah Huber, and Sotirios V Archontoulis. Coupling machine learning and crop modeling improves crop yield prediction in the us corn belt. Scientific reports, 2021.", + "[43] Xingjian Shi, Zhourong Chen, Hao Wang, Dit-Yan Yeung, Wai-Kin Wong, and Wang-chun Woo. Convolutional LSTM network: A machine learning approach for precipitation nowcasting. In Neural Information Processing Systems (NeurIPS), 2015.", + "[44] Fulu Tao, Masayuki Yokozawa, and Zhao Zhang. Modelling the impacts of weather and climate variability on crop pro" + ], + "bbox": [ + 78, + 90, + 468, + 900 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "ductivity over a large area: a new process-based model development, optimization, and uncertainties analysis. agricultural and forest meteorology, 2009.", + "[45] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. VideoMAE: Masked autoencoders are data-efficient learners for self-supervised video pre-training. In Neural Information Processing Systems (NeurIPS), 2022.", + "[46] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Hervé Jégou. Training data-efficient image transformers & distillation through attention. In Marina Meila and Tong Zhang, editors, International Conference on Machine Learning (ICML), 2021.", + "[47] Gabriel Tseng, Ivan Zvonkov, Catherine Nakalembe, and Hannah Kerner. Cropharvest: a global satellite dataset for crop type classification. Neural Information Processing Systems (NeurIPS), 2021.", + "[48] Matteo Turchetta, Luca Corinzia, Scott Sussex, Amanda Burton, Juan Herrera, Ioannis N Athanasiadis, Joachim M Buhmann, and Andreas Krause. Learning long-term crop management strategies with cyclesgym. In Neural Information Processing Systems (NeurIPS), 2022.", + "[49] USDA. The united states department of agriculture (usda), 2022.", + "[50] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Neural Information Processing Systems (NeurIPS), 2017.", + "[51] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In International Conference on Computer Vision (ICCV), pages 548-558, 2021.", + "[52] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. PVT v2: Improved baselines with pyramid vision transformer. Comput. Vis. Media, 2022.", + "[53] Xiaocui Wu, Xiangming Xiao, Jean Steiner, Zhengwei Yang, Yuanwei Qin, and Jie Wang. Spatiotemporal changes of winter wheat planted and harvested areas, photosynthesis and grain production in the contiguous united states from 2008-2018. Remote Sensing, 2021.", + "[54] Rongting Xu, Hanqin Tian, Shufen Pan, Stephen A Prior, Yucheng Feng, William D Batchelor, Jian Chen, and Jia Yang. Global ammonia emissions from synthetic nitrogen fertilizer applications in agricultural systems: Empirical and process-based estimates and uncertainty. *Global change biology*, 2019.", + "[55] Li Yuan, Yunpeng Chen, Tao Wang, Weihao Yu, Yujun Shi, Zihang Jiang, Francis E. H. Tay, Jiashi Feng, and Shuicheng Yan. Tokens-to-token vit: Training vision transformers from scratch onImagenet. In International Conference on Computer Vision (ICCV), 2021.", + "[56] Yihe Zhang, Xu Yuan, Sytske K. Kimball, Eric Rappin, Li Chen, Paul J. Darby III, Tom Johnsten, Lu Peng, Boisy Pitre, David Bourrie, and Nian-Feng Tzeng. Precise weather parameter predictions for target regions via neural networks. In ECML-PKDD. Applied Data Science Track, 2021." + ], + "bbox": [ + 501, + 92, + 890, + 893 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "5784", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/8b54a15b-f3ee-46da-88b3-5c8950b9cb49_model.json b/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/8b54a15b-f3ee-46da-88b3-5c8950b9cb49_model.json new file mode 100644 index 0000000000000000000000000000000000000000..8f1db25f4978f7ef3a9dec106c2c6c2ed0f0290c --- /dev/null +++ b/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/8b54a15b-f3ee-46da-88b3-5c8950b9cb49_model.json @@ -0,0 +1,2268 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.105, + 0.13, + 0.868, + 0.177 + ], + "angle": 0, + "content": "MMST-ViT: Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer" + }, + { + "type": "text", + "bbox": [ + 0.086, + 0.203, + 0.91, + 0.311 + ], + "angle": 0, + "content": "Fudong Lin\\(^{1}\\), Summer Crawford\\(^{2}\\), Kaleb Guillot\\(^{2}\\), Yihe Zhang\\(^{2}\\), Yan Chen\\(^{3}\\), Xu Yuan\\(^{1*}\\), Li Chen\\(^{2}\\), Shelby Williams\\(^{2}\\), Robert Minvielle\\(^{2}\\), Xiangming Xiao\\(^{4}\\), Drew Gholson\\(^{5}\\), Nicolas Ashwell\\(^{5}\\), Tri Setiyono\\(^{6}\\), Brenda Tubana\\(^{7}\\), Lu Peng\\(^{8}\\), Magdy Bayoumi\\(^{2}\\), Nian-Feng Tzeng\\(^{2}\\) \n\\(^{1}\\) University of Delaware, \\(^{2}\\) University of Louisiana at Lafayette, \\(^{3}\\) University of Connecticut, \\(^{4}\\) University of Oklahoma, \\(^{5}\\) Mississippi State University, \\(^{6}\\) Louisiana State University, \\(^{7}\\) LSU AgCenter, \\(^{8}\\) Tulane University" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.345, + 0.314, + 0.361 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.377, + 0.474, + 0.861 + ], + "angle": 0, + "content": "Precise crop yield prediction provides valuable information for agricultural planning and decision-making processes. However, timely predicting crop yields remains challenging as crop growth is sensitive to growing season weather variation and climate change. In this work, we develop a deep learning-based solution, namely Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), for predicting crop yields at the county level across the United States, by considering the effects of short-term meteorological variations during the growing season and the long-term climate change on crops. Specifically, our MMST-ViT consists of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer. The Multi-Modal Transformer leverages both visual remote sensing data and short-term meteorological data for modeling the effect of growing season weather variations on crop growth. The Spatial Transformer learns the high-resolution spatial dependency among counties for accurate agricultural tracking. The Temporal Transformer captures the long-range temporal dependency for learning the impact of long-term climate change on crops. Meanwhile, we also devise a novel multi-modal contrastive learning technique to pre-train our model without extensive human supervision. Hence, our MMST-ViT captures the impacts of both short-term weather variations and long-term climate change on crops by leveraging both satellite images and meteorological data. We have conducted extensive experiments on over 200 counties in the United States, with the experimental results exhibiting that our MMST-ViT outperforms its counterparts under three performance metrics of interest. Our dataset and code are available at https://github.com/fudong03/MMST-ViT." + }, + { + "type": "title", + "bbox": [ + 0.502, + 0.345, + 0.632, + 0.361 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.37, + 0.895, + 0.673 + ], + "angle": 0, + "content": "Accurate crop yield prediction is essential for agricultural planning and advisory processes [26], informed economic decisions [2], and global food security [36]. However, predicting crop yields precisely is challenging as it requires to consider the effects of i) short-term weather variations, governed by the meteorological data during the growing season, and ii) long-term climate change, governed by historical meteorological factors, on crops simultaneously. Meanwhile, precise crop tracking relies on high-resolution remote sensing data. While process-based prediction approaches [44, 11, 25, 54] exist, they often suffer from high inaccuracies due to their strong assumptions on management practices [15]. On the other hand, motivated by the recent success of deep neural networks [29, 19, 50, 12, 20, 56, 37, 32, 18, 30, 8], deep learning (DL)-based methods have been widely adopted for crop yield predictions, due to their effectiveness in accurate agricultural tracking [27, 26] and their potent capabilities in capturing the spatial and temporal variation of meteorological data [28, 15]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.673, + 0.895, + 0.87 + ], + "angle": 0, + "content": "So far, DL-based solutions for crop yield predictions can be roughly grouped into two categories, i.e., remote sensing data-based and meteorological data-based approaches. The former [27, 26, 53, 13, 17, 47, 10] employs such remote sensing data as satellite images, unmanned aerial vehicle (UAV)-based imagery data, or vegetation indices to estimate the annual crop yield, while the latter [16, 1, 36, 42, 48] predicts the crop yield by using meteorological parameter data, including temperature, precipitation, vapor pressure deficit, etc. However, the former overlooks the direct impact of meteorological parameters on crop growth, while the latter lacks high-resolution remote sensing data for accurate agricultural tracking." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.895, + 0.903 + ], + "angle": 0, + "content": "A recent study [39] has reported that the long-term climate change would gradually decrease the crop yield." + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.395, + 0.901 + ], + "angle": 0, + "content": "*Corresponding author: Dr. Xu Yuan (xyuan@udel.edu)" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.517, + 0.958 + ], + "angle": 0, + "content": "5774" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.081, + 0.092, + 0.468, + 0.317 + ], + "angle": 0, + "content": "Driven by this discovery, follow-up pursuits have attempted to explore the effect of long-term climate change on crops. For example, the CNN-RNN model [28] demonstrates that the crop yield prediction can benefit from historical meteorological data, which is essential for measuring the impacts of climate change. Later, GNN-RNN [15] extends CNN-RNN by framing the crop yield prediction as the Spatial-Temporal forecasting problem. It employs Graph Neural Networks (GNN) and Long Short-Term Memory (LSTM) [22] respectively for learning spatial dependency among neighborhood counties and for capturing the impact of long-term meteorological data on crops. However, both of them only take into account the meteorological data for predictions, failing to leverage the remote sensing data for accurate agricultural tracking." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.327, + 0.468, + 0.9 + ], + "angle": 0, + "content": "In this work, we aim to develop a new DL-based solution for predicting crop yields at the county level across the United States, by using both visual remote sensing data (from the Sentinel-2 satellite imagery [41]) and numerical meteorological data (from the HRRR model [24]). Our solution has two main goals. First, it captures the impacts of both short-term growing season weather variations and long-term climate change on crops. Second, it aims to leverage high-resolution remote sensing data for accurate agricultural tracking. To achieve our goals, we propose the Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), motivated by the recent success of Vision Transformers (ViT) [12]. To the best of our knowledge, MMST-ViT is the first ViT-based model for real-world crop yield prediction. It advances previous CNN/GNN-based and RNN-based counterparts respectively with better generalization to the multi-model data and with more powerful abilities in capturing long-term temporal dependency. Its three components of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer are each equipped with one novel Multi-Head Attention (MHA) mechanism [50]. Specifically, the Multi-Modal Transformer leverages satellite images and meteorological data during the growing season for capturing the direct impact of short-term weather variations on crop growth. The Spatial Transformer learns high-resolution spatial dependency among counties for precise crop tracking. The Temporal Transformer captures the effects of long-term climate change on crops. Since ViT-based models are prone to overfitting [12], we also develop a novel multi-modal contrastive learning technique that pre-trains our Multi-Modal Transformer without requiring human supervision. We have conducted experiments on over 200 counties in the United States. The experimental results exhibit that our MMST-ViT outperforms its state-of-the-art counterparts under three performance metrics of interest. For example, on the soybean prediction, our MMST-ViT achieves the lowest Root Mean Square Error (RMSE) value of 3.9, the highest R" + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.093, + 0.89, + 0.12 + ], + "angle": 0, + "content": "squared \\((\\mathbb{R}^2)\\) value of 0.843, and the best Pearson Correlation Coefficient (Corr) value of 0.918." + }, + { + "type": "title", + "bbox": [ + 0.504, + 0.14, + 0.64, + 0.154 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.171, + 0.89, + 0.577 + ], + "angle": 0, + "content": "Vision Transformers. Adopted from Transformers [50] in natural language processing, Vision Transformers (ViT) have exhibited commendable performance in various computer vision tasks. The original ViT [12] first partitions an image into a set of image patches, then applies Multi-Head Attention (MHA) [50] over the patches, and finally utilizes a learnable classification token to capture global visual representation for image classification. Several subsequent methods have been developed, including DeiT [46] for data-efficient ViT through knowledge distillation, Swin [33] for computation-efficient ViT using shifted windows, PVT [51] for dense prediction tasks, and MAE [18] for self-supervised learning, among others [7, 21, 14, 55, 3, 52, 31, 45]. However, applying prior ViT approaches to real-world crop yield prediction is challenging due to its needs of addressing the multi-modal inputs, of learning high-resolution spatial dependency, and of capturing long-range temporal dependency. Our work, based on ViT, advances existing methods by proposing three novel Multi-Head Attention (MHA) mechanisms respectively for leveraging both visual remote sensing data and numerical meteorological data, learning global spatial representation from multiple high-resolution data, and capturing the global temporal representation for measuring the long-term climate change effect. Additionally, we develop a new multi-modal contrastive learning technique to pre-train our multi-modal model for better prediction performance." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.585, + 0.89, + 0.899 + ], + "angle": 0, + "content": "Deep Learning (DL) for Crop Yield Prediction. DL has been widely adopted for real-world crop yield predictions. Such prediction studies can be grouped into two categories: remote sensing data-based and meteorological data-based approaches. The former uses satellite images, unmanned aerial vehicle (UAV) data, or vegetation indices to estimate crop yields. Its prominent studies include the use of UAV-acquired RGB images [27] for predicting in-season crop yields, YieldNet [26] which resorts to transfer learning for simultaneously estimating the yields of multiple crop types, among many others [53, 13, 17, 47, 10]. By contrast, the latter utilizes deep neural networks (DNNs) to capture the impact of meteorological parameters on crop yields, including CNN-RNN [28] which incorporates long-term meteorological data, GNN-RNN [15] which extends CNN-RNN by using Graph Neural Networks (GNN) for learning spatial information, and others [16, 1, 36, 42, 48]. However, the remote sensing data-based solutions overlook the impact of meteorological parameters on crops, while the meteorological data-based solutions often fail to incorporate the remote sensing data, known to be crucial for accurate agricultural" + }, + { + "type": "page_number", + "bbox": [ + 0.485, + 0.947, + 0.514, + 0.957 + ], + "angle": 0, + "content": "5775" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.089, + 0.47, + 0.12 + ], + "angle": 0, + "content": "Table 1: Overview of USDA Crop Dataset and HRRR Computed Dataset" + }, + { + "type": "table", + "bbox": [ + 0.078, + 0.128, + 0.472, + 0.2 + ], + "angle": 0, + "content": "
DatasetParameters
USDAProduction, Yield
HRRRAveraged Temperature, Maximal Temperature, Minimal Temperature, Precipitation, Relative Humidity, Wind Gust, Wind Speed, Downward Shortwave Radiation Flux, Vapor Pressure Deficit
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.215, + 0.471, + 0.352 + ], + "angle": 0, + "content": "tracking. Our work differs from prior studies in two aspects. First, it leverages both remote sensing data and meteorological data for capturing the impacts of both short-term growing season meteorological variations and the long-term climate change on crops. Second, it is the first to use Vision Transformers for crop yield predictions, advancing previous CNN/GNN- and RNN-based models respectively with better generalization to multi-modal data and with higher abilities for capturing long ranges of temporal dependency." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.367, + 0.173, + 0.383 + ], + "angle": 0, + "content": "3. Datasets" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.392, + 0.47, + 0.482 + ], + "angle": 0, + "content": "In this study, we utilize three types of data for accurate county-level crop yield predictions: i) crop data from the United States Department of Agriculture (USDA), ii) meteorological data from the High-Resolution Rapid Refresh (HRRR), and iii) remote sensing data from the Sentinel-2 satellite, as outlined below." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.487, + 0.47, + 0.594 + ], + "angle": 0, + "content": "USDA Crop Dataset. The dataset, sourced from the United States Department of Agriculture (USDA) [49], provides annual crop data for major crops grown in the United States (U.S.), including corn, cotton, soybean, winter wheat, etc., on a county-level basis. It covers crop information such as production and yield from 2017 to 2022 (as listed in the second row of Table 1)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.598, + 0.47, + 0.689 + ], + "angle": 0, + "content": "HRRR Computed Dataset. The dataset, obtained from the High-Resolution Rapid Refresh atmospheric model (HRRR) [24], provides high-resolution meteorological data for the contiguous U.S. continent. It covers 9 weather parameters from 2017 to 2022 (see the third row in Table 1 for more information)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.693, + 0.471, + 0.815 + ], + "angle": 0, + "content": "Sentinel-2 Imagery. Sentinel-2 imagery is a set of images captured by the Sentinel-2 Earth observation satellite. It provides agriculture imagery for the contiguous U.S. continent from 2017 to 2022 with a 2-week interval. Since precise agricultural tracking requires high-resolution remote sensing data, the image of a county is partitioned into multiple fine-grained grids \\((9 \\times 9 \\mathrm{~km})\\). Figure 1 shows an example of county partitioning." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.83, + 0.168, + 0.845 + ], + "angle": 0, + "content": "4. Method" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.47, + 0.901 + ], + "angle": 0, + "content": "In this work, we aim to develop a deep learning (DL)-based model for predicting crop yields at the county level. Our goals are twofold. First, we plan to capture the mete" + }, + { + "type": "image", + "bbox": [ + 0.513, + 0.093, + 0.695, + 0.269 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.547, + 0.281, + 0.655, + 0.296 + ], + "angle": 0, + "content": "(a) Grid Example" + }, + { + "type": "image", + "bbox": [ + 0.704, + 0.094, + 0.878, + 0.273 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.724, + 0.282, + 0.859, + 0.296 + ], + "angle": 0, + "content": "(b) Sentinel-2 Imagery" + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.301, + 0.892, + 0.407 + ], + "angle": 0, + "content": "Figure 1: Illustration of partitioning a county into multiple grids at the \\(9\\mathrm{km}\\) high-resolution. (a) An example of county partitioning, with the red line segments indicating the geometry boundary for the county and the blue line segments representing the high-resolution grids. (b) The resulting satellite images in the Sentinel-2 Imagery, with each composed of \\(384\\times 384\\) pixels, depicting an area of \\(9\\times 9\\mathrm{km}\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.414, + 0.892, + 0.492 + ], + "angle": 0, + "content": "orological effect, including growing season weather variations and climate change, on crop yields. Second, we aim to leverage high-resolution satellite images for precise agricultural tracking. The aforementioned three data sources are utilized for achieving our goals." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.498, + 0.685, + 0.513 + ], + "angle": 0, + "content": "4.1. Problem Statement" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.522, + 0.892, + 0.84 + ], + "angle": 0, + "content": "We consider the combination of four types of data \\((\\boldsymbol{x},\\boldsymbol{y}_s,\\boldsymbol{y}_l,\\boldsymbol{z})\\) for predicting the crop yield at each single U.S. county. Specifically, \\(\\boldsymbol{x} \\in \\mathbb{R}^{T \\times G \\times H \\times W \\times C}\\) represents satellite images obtained from Sentinel-2 imagery, which capture the information of field crops on the ground. \\(T\\) and \\(G\\) indicate the numbers of temporal and spatial data, respectively, whereas \\(H\\), \\(W\\), and \\(C\\) are the height, width, and number of channels in the satellite image. \\(\\boldsymbol{y}_s \\in \\mathbb{R}^{T \\times G \\times N_1 \\times d_y}\\) and \\(\\boldsymbol{y}_l \\in \\mathbb{R}^{T \\times N_2 \\times d_y}\\) are meteorological parameters obtained from the HRRR dataset, representing the short-term and the long-term historical data, respectively. Here, \\(N_1\\) and \\(N_2\\) are the numbers of daily and monthly HRRR data points, respectively, and \\(d_y\\) indicates the number of weather parameters. Note that the short-term meteorological data is the daily HRRR data during the growing season, while the long-term historical meteorological data is the monthly HRRR data from the past several years (e.g., 2018 to 2020 for predicting crop yields in 2021). \\(\\boldsymbol{z} \\in \\mathbb{R}^{d_z}\\) is the ground-truth crop information obtained from the USDA dataset, with \\(d_z\\) representing the number of parameters for the crop data." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.848, + 0.622, + 0.864 + ], + "angle": 0, + "content": "4.2. Challenges" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.89, + 0.9 + ], + "angle": 0, + "content": "Three challenges exist upon achieving our goals, outlined as follows." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5776" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.191, + 0.094, + 0.778, + 0.397 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.3, + 0.404, + 0.668, + 0.42 + ], + "angle": 0, + "content": "Figure 2: The architecture of our proposed MMST-ViT." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.428, + 0.473, + 0.594 + ], + "angle": 0, + "content": "Capturing the Effect of Growing Season Weather Variations on Crop Growth. Previous studies only consider the meteorological data (or the remote sensing data) for crop yield predictions, overlooking the direct impact of growing season weather variations on crop growth. To capture such an impact, we aim to leverage both visual remote sensing and numerical meteorological data. In particular, the Multi-Head Attention (MHA) technique [50] is adopted to capture the meteorological effects on crop growth. However, how to perform multi-modal attention over visual remote sensing data and numerical meteorological data remains open." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.597, + 0.47, + 0.762 + ], + "angle": 0, + "content": "Lacking a Mechanism for Pre-training Multi-Modal Model. Deep neural networks (DNNs), especially Vision Transformer (ViT)-based models, are prone to overfitting, requiring appropriate pre-training to achieve satisfactory performance. Unfortunately, conventional pretraining techniques (e.g., SimCLR [9]) only marginally improve crop yield prediction performance as they consider the visual data only, ineffective for pre-training multi-modal models. How to pre-train the multi-modal model for satisfactory crop yield predictions is challenging to be addressed." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Capturing the Impact of Climate Change on Crops. As reported by a prior study [39], the long-term climate change in the atmosphere would gradually decrease the crop yield on the ground. Some studies [28, 15] have demonstrated that taking the climate change effect into account can better crop yield prediction. But their designs overlook the remote sensing data, viewed as essential for precise agricultural tracking. So far, how to develop effective ways to capture the impact of long-term climate change on crop yields" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.428, + 0.733, + 0.443 + ], + "angle": 0, + "content": "is challenging and unanswered yet." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.45, + 0.726, + 0.466 + ], + "angle": 0, + "content": "4.3. Our Proposed Approach" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.473, + 0.892, + 0.548 + ], + "angle": 0, + "content": "To tackle the aforementioned challenges, we develop the Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT) for predicting crop yields at the county level, by leveraging the remote sensing data and the short-term and long-term meteorological data." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.551, + 0.893, + 0.806 + ], + "angle": 0, + "content": "Model Overview. Our proposed MMST-ViT consists of three key components, i.e., Multi-Modal Transformer, Spatial Transformer, and Temporal Transformer, as shown in Figure 2. The Multi-Modal Transformer is designed to capture the impact of short-term meteorological variations on crop growth, by leveraging the satellite images (i.e., \\( \\mathbf{x} \\)) and the short-term meteorological parameters (i.e., \\( \\mathbf{y}_s \\)). The Spatial Transformer then utilizes the output of the Multi-Modal Transformer for learning the global spatial information of a county. Next, the Temporal Transformer combines the outputs of our Spatial Transformer and the long-term meteorological data (i.e., \\( \\mathbf{y}_l \\)) to capture both global temporal information and the impact of long-term climate change on crop yields. Finally, the output of our Temporal Transformer is used by a linear classifier for predicting the annual crop yields. The details of each component are provided below." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.894, + 0.902 + ], + "angle": 0, + "content": "Multi-Modal Transformer. Aiming to capture the direct impact of atmospheric weather variations on crop growth, the Multi-Modal Transformer consists of a visual backbone network and a multi-modal attention layer. The former extracts high-quality visual representations from satellite images for accurate agricultural tracking, while the lat" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5777" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.272 + ], + "angle": 0, + "content": "ter captures the relationship between the visual representation and meteorological parameters, to understand the impact of meteorological parameters on crop growth. Let \\( f_{\\theta} \\colon (\\mathbb{R}^{T \\times G \\times H \\times W \\times C}, \\mathbb{R}^{T \\times G \\times N_1 \\times d_y}) \\to \\mathbb{R}^{T \\times G \\times d} \\) be our Multi-Modal Transformer, with \\( \\pmb{\\theta} \\) denoting the parameters for DNNs and \\( d \\) representing the dimension for hidden vectors. Notably, all the hidden dimensions in this paper are set to the same size of \\( d \\). As such, the proposed Multi-Modal Transformer can be expressed as \\( f_{\\theta}(x, y_s) = v_m \\), where \\( x \\) and \\( y_s \\) are the Sentinel-2 images and the short-term meteorological data, respectively. \\( v_m \\in \\mathbb{R}^{T \\times G \\times d} \\) is the output of our Multi-Modal Transformer." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.273, + 0.474, + 0.515 + ], + "angle": 0, + "content": "In this work, we utilize Pyramid Vision Transformer (PVT) [51] as the visual backbone network since it advances ResNet [19] and vanilla ViT [12] respectively by having the global receptive field and by enabling high-resolution feature maps. To capture the direct impact of meteorological parameters on crop growth during the growing season, a naive way is by concatenating visual and numerical representations extracted respectively from the Sentinel-2 images and the meteorological parameters. Unfortunately, our empirical results show that such a naive way cannot achieve satisfactory performance. Inspired by the recent success of multi-head attention mechanisms [50, 12, 40], we devise a novel Multi-Modal Multi-Head Attention (MM-MHA) mechanism to capture the impact of meteorological parameters on crop growth, mathematically expressed as" + }, + { + "type": "equation", + "bbox": [ + 0.097, + 0.526, + 0.43, + 0.544 + ], + "angle": 0, + "content": "\\[\n\\operatorname {M M - M H A} (\\boldsymbol {Q}, \\boldsymbol {K}, \\boldsymbol {V}) = \\operatorname {S o f t m a x} (\\boldsymbol {Q} \\boldsymbol {K} ^ {T} / \\sqrt {d}) \\boldsymbol {V},\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.124, + 0.547, + 0.469, + 0.565 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {Q} = \\boldsymbol {W} _ {m} ^ {Q} \\cdot \\varphi_ {m} (\\boldsymbol {x}), \\boldsymbol {K} = \\boldsymbol {W} _ {m} ^ {K} \\cdot \\pi_ {m} (\\boldsymbol {y} _ {s}), \\tag {1}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.196, + 0.568, + 0.334, + 0.586 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {V} = \\boldsymbol {W} _ {m} ^ {V} \\cdot \\pi_ {m} (\\boldsymbol {y} _ {s}).\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.598, + 0.47, + 0.734 + ], + "angle": 0, + "content": "Here, \\(\\varphi_{m}(\\pmb{x})\\in \\mathbb{R}^{T\\times G\\times N_{p}\\times d}\\) is the visual representation encoded by PVT, with \\(N_{p}\\) indicating the number of image patches. \\(\\pi_m(\\pmb {y}_s)\\in \\mathbb{R}^{T\\times G\\times N_1\\times d}\\) is the meteorological parameters after the linear projection. Notably, \\(\\pmb{W}_{m}^{Q},\\pmb{W}_{m}^{K}\\), and \\(\\pmb{W}_{m}^{V}\\) are learnable projection matrices, similar to those in prior studies [50, 40]. To our knowledge, this is the first attempt at developing a multi-modal multi-attention approach for leveraging both visual remote sensing data and numerical meteorological data." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.471, + 0.901 + ], + "angle": 0, + "content": "However, ViT-based models are highly sensitive to overfitting, calling for pre-training with millions of visual data [12]. Meanwhile, real-world crop yield prediction usually lacks sufficient crop data for pre-training. Worse still, capturing the impact of short-term weather conditions on crops requires considering both the visual and the numerical data simultaneously. Although self-supervised learning techniques [9, 5, 18] have recently been developed for pretraining DNNs, they cannot tackle the aforementioned issue at the same time. For example, SimCLR [9] fails to address the multi-modal data issue." + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.096, + 0.895, + 0.337 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.537, + 0.35, + 0.855, + 0.366 + ], + "angle": 0, + "content": "Figure 3: Multi-modal self-supervised learning." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.378, + 0.895, + 0.771 + ], + "angle": 0, + "content": "Here, we propose a novel multi-modal self-supervised learning for pre-training our Multi-Modal Transformer without human supervision, which is inspired by SimCLR, but having two differences. First, we utilize the PVT instead of convolutional neural networks (CNNs) as the backbone network since PVT advances CNNs by having a global receptive field [51]. Second, we replace the Multi-Layer Perceptron (MLP) layer in SimCLR with our proposed multimodal self-attention layer (i.e., Eq. (1)) for simultaneously tackling visual and numerical data. Figure 3 illustrates its architecture. Given a satellite image \\( \\pmb{x}^m \\) (or \\( \\pmb{x}^n \\)), we perform the data augmentation to get its two augmented images, and then feed them to the PVT to get two sets of visual representations. After that, we use our proposed MM-MHA (i.e., Eq. (1)) to perform multi-modal attention between the visual representations and the corresponding short-term parameters \\( \\pmb{y}_s^m \\) (or \\( \\pmb{y}_s^n \\)), arriving at two sets of output sequences. Here, we regard two sets of output sequences out of a given satellite image (e.g., \\( \\pmb{x}^m \\)) as the positive pair. Meanwhile, two sets of output sequences from different satellite images (e.g., \\( \\pmb{x}^m \\) and \\( \\pmb{x}^n \\)) are regarded as the negative pair. Similar to vanilla ViT [12], the head of output sequences (i.e., the classification token) is taken as the output of our Multi-Modal Transformer, i.e., the hidden vector \\( \\pmb{v}_m \\). As such, our multi-modal contrastive loss is defined as," + }, + { + "type": "equation", + "bbox": [ + 0.514, + 0.777, + 0.877, + 0.814 + ], + "angle": 0, + "content": "\\[\n\\ell (i, j) = - \\log \\frac {\\exp (\\operatorname {s i m} \\left(\\boldsymbol {v} _ {m} ^ {i} , \\boldsymbol {v} _ {m} ^ {j}\\right) / \\tau)}{\\sum_ {i \\neq k , k = 1 , \\dots , 2 B} \\exp (\\operatorname {s i m} \\left(\\boldsymbol {v} _ {m} ^ {i} , \\boldsymbol {v} _ {m} ^ {k}\\right) / \\tau)},\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.556, + 0.817, + 0.891, + 0.87 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {c l}} = \\frac {1}{2 B} \\sum_ {k = 1} ^ {B} [ \\ell (k, k + B) + \\ell (k + B, k) ], \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.871, + 0.893, + 0.902 + ], + "angle": 0, + "content": "where \\(B = T \\times G\\). Here, \\(\\pmb{v}_m^i\\) and \\(\\pmb{v}_m^j\\) are the positive pair, and \\(\\tau\\) is the temperature parameter. Intuitively, our" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5778" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.198 + ], + "angle": 0, + "content": "Eq. (2) encourages two hidden vectors from the same satellite image (i.e., representing the same region) to be similar, and two hidden vectors from different satellite images (i.e., representing different regions) to be dissimilar. As such, we can pre-train our Multi-Modal Transformer to capture the impact of short-term meteorological parameters on crop growth without labor-intensive human supervision." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.2, + 0.471, + 0.398 + ], + "angle": 0, + "content": "Spatial Transformer. Recall that the Sentinel-2 Imagery dataset of a county is partitioned into multiple fine-grained grids for precise agricultural tracking. To learn spatial dependency among those grids, we propose a Spatial Transformer \\( g_{\\phi} : \\mathbb{R}^{T \\times G \\times d} \\to \\mathbb{R}^{T \\times d} \\), whose purpose is to capture the global spatial representations for counties. The design of our Spatial Transformer is inspired by the vanilla ViT [12] but with a flexible number of positional embeddings. It is used to tackle the scenario that the number of grids varies among counties as it depends on county sizes. To learn global spatial information for counties, the Spatial Transformer prepends a learnable classification token \\( v_{m}^{\\mathrm{cls}} \\in \\mathbb{R}^{T \\times 1 \\times d} \\), arriving at" + }, + { + "type": "equation", + "bbox": [ + 0.122, + 0.402, + 0.469, + 0.421 + ], + "angle": 0, + "content": "\\[\n\\varphi_ {s} \\left(\\boldsymbol {v} _ {m}\\right) = \\left[ \\boldsymbol {v} _ {m} ^ {\\text {c l s}}; \\boldsymbol {v} _ {m} ^ {1}; \\boldsymbol {v} _ {m} ^ {2}; \\dots ; \\boldsymbol {v} _ {m} ^ {G} \\right] + \\mathbf {E} _ {\\text {p o s}}, \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.428, + 0.469, + 0.49 + ], + "angle": 0, + "content": "where \\(\\mathbf{E}_{\\mathrm{pos}} \\in \\mathbb{R}^{T \\times (G + 1) \\times d}\\) is the flexible positional embeddings. We propose a Spatial Multi-Head Attention (S-MHA) to learn spatial dependency among grids. Mathematically," + }, + { + "type": "equation", + "bbox": [ + 0.116, + 0.496, + 0.43, + 0.514 + ], + "angle": 0, + "content": "\\[\n\\operatorname {S - M H A} (\\boldsymbol {Q}, \\boldsymbol {K}, \\boldsymbol {V}) = \\operatorname {S o f t m a x} (\\boldsymbol {Q} \\boldsymbol {K} ^ {T} / \\sqrt {d}) \\boldsymbol {V},\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.13, + 0.517, + 0.469, + 0.535 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {Q} = \\boldsymbol {W} _ {s} ^ {Q} \\cdot \\varphi_ {s} (\\boldsymbol {v} _ {m}), \\boldsymbol {K} = \\boldsymbol {W} _ {s} ^ {K} \\cdot \\varphi_ {s} (\\boldsymbol {v} _ {m}), \\tag {4}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.212, + 0.538, + 0.352, + 0.555 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {V} = \\boldsymbol {W} _ {s} ^ {V} \\cdot \\varphi_ {s} (\\boldsymbol {v} _ {m}).\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.563, + 0.469, + 0.653 + ], + "angle": 0, + "content": "Here, \\( \\boldsymbol{W}_s^Q, \\boldsymbol{W}_s^K, \\boldsymbol{W}_s^V \\) are three learnable matrices, similar to those given in Eq. (1). Finally, we regard the head of output sequences as global spatial representations of counties. That is, we have \\( g_{\\phi}(\\boldsymbol{v}_m) = \\boldsymbol{v}_s \\), with \\( \\boldsymbol{v}_s \\in \\mathbb{R}^{T \\times d} \\) signifying the hidden vector that incorporates global spatial information." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.657, + 0.469, + 0.763 + ], + "angle": 0, + "content": "Temporal Transformer. The Temporal Transformer possesses two goals. The first goal aims to learn temporal dependency among the hidden vectors \\( \\boldsymbol{v}_s \\), i.e., the outputs of our Spatial Transformer. The second goal is to capture the effect of long-term climate change on crop yields. To achieve the first goal, we add a classification token \\( \\boldsymbol{v}_s^{\\mathrm{cls}} \\) for learning the global temporal representation, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.129, + 0.769, + 0.469, + 0.787 + ], + "angle": 0, + "content": "\\[\n\\varphi_ {t} \\left(\\boldsymbol {v} _ {s}\\right) = \\left[ \\boldsymbol {v} _ {s} ^ {\\text {c l s}}; \\boldsymbol {v} _ {s} ^ {1}; \\boldsymbol {v} _ {s} ^ {2}; \\dots ; \\boldsymbol {v} _ {s} ^ {T} \\right] + \\mathbf {E} _ {\\text {t m p}}, \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.469, + 0.901 + ], + "angle": 0, + "content": "where \\(\\mathbf{E}_{\\mathrm{tmp}} \\in \\mathbb{R}^{(T + 1) \\times d}\\) is the temporal embedding, similar to the positional embeddings \\(\\mathbf{E}_{\\mathrm{pos}}\\) expressed in Eq. (3). The novel Temporal Multi-Head Attention (T-MHA) is also devised to capture the impact of long-term historical meteorological parameters on crop yields. Its key idea is to incorporate a relative meteorological bias into each head for similarity computation, motivated by prior studies [6, 38, 33]." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.092, + 0.827, + 0.107 + ], + "angle": 0, + "content": "Mathematically, our T-MHA can be expressed by" + }, + { + "type": "equation", + "bbox": [ + 0.508, + 0.119, + 0.89, + 0.192 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\operatorname {T} - \\operatorname {M H A} (\\boldsymbol {Q}, \\boldsymbol {K}, \\boldsymbol {V}) = \\operatorname {S o f t m a x} (\\boldsymbol {Q} \\boldsymbol {K} ^ {\\boldsymbol {T}} / \\sqrt {d} + \\pi_ {t} (\\boldsymbol {y} _ {l})) \\boldsymbol {V}, \\\\ \\boldsymbol {Q} = \\boldsymbol {W} _ {t} ^ {Q} \\cdot \\varphi_ {t} (\\boldsymbol {v} _ {s}), \\boldsymbol {K} = \\boldsymbol {W} _ {t} ^ {K} \\cdot \\varphi_ {t} (\\boldsymbol {v} _ {s}), \\\\ \\boldsymbol {V} = \\boldsymbol {W} _ {t} ^ {V} \\cdot \\varphi_ {t} (\\boldsymbol {v} _ {s}). \\tag {6} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.193, + 0.892, + 0.313 + ], + "angle": 0, + "content": "Here, \\(\\pmb{y}_l\\) represents the long-term meteorological parameters, and \\(\\pi_t(\\cdot)\\) is a linear projection layer. Similarly, \\(\\pmb{W}_t^Q\\), \\(\\pmb{W}_t^K\\), \\(\\pmb{W}_t^V\\) are three learnable matrices. In summary, our Temporal Transformer \\(h_\\psi : (\\mathbb{R}^{T \\times d}, \\mathbb{R}^{T \\times N_2 \\times d_y}) \\to \\mathbb{R}^d\\) can be defined as \\(h_\\psi(\\pmb{v}_s, \\pmb{y}_l) = \\pmb{v}_t\\), with \\(\\pmb{v}_t \\in \\mathbb{R}^d\\) being the hidden vector that incorporates both global temporal information and the impact of climate change on crops simultaneously." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.314, + 0.892, + 0.375 + ], + "angle": 0, + "content": "Finally, the hidden vector \\(\\pmb{v}_t\\) is fed into a linear classifier for crop yield predictions, i.e., \\(\\hat{\\pmb{z}} = \\pmb{W}^T\\pmb{v}_t + \\pmb{b}\\), with \\(\\pmb{W}\\) and \\(\\pmb{b}\\) respectively denoting the weights and the bias for the classifier, and \\(\\hat{\\pmb{z}} \\in \\mathbb{R}^{d_z}\\) indicating the crop yield prediction." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.388, + 0.633, + 0.405 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.414, + 0.892, + 0.49 + ], + "angle": 0, + "content": "We conduct experiments for the county-level crop yield predictions across four U.S. states, i.e., Mississippi (MS), Louisiana (LA), Iowa (IA), and Illinois (IL). Four types of crops, i.e., corn, cotton, soybean, and winter wheat, are taken into account for performance evaluation." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.499, + 0.707, + 0.515 + ], + "angle": 0, + "content": "5.1. Experimental Settings" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.526, + 0.892, + 0.617 + ], + "angle": 0, + "content": "Datasets. We utilize the Sentinel-2 imagery and the daily HRRR data datasets during the growing season respectively as the remote sensing data and the short-term meteorological data. Meanwhile, the monthly HRRR data from the previous three years are used as the long-term meteorological parameters." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.621, + 0.892, + 0.757 + ], + "angle": 0, + "content": "Compared Approaches. We compare our proposed MMST-ViT to three DL-based approaches, with one, i.e., ConvLSTM [43], developed for spatial-temporal prediction, and the other two, i.e., CNN-RNN [28] and GNN-RNN [15], developed for crop yield predictions. Minor rectifications are made to them so that they can admit the Sentinel-2 imagery and HRRR datasets as their inputs. Other hyperparameters, unless specified otherwise, are set to the values as those reported in their original studies." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.761, + 0.892, + 0.837 + ], + "angle": 0, + "content": "Metrics. We take three performance metrics, i.e., Root Mean Square Error (RMSE), R-squared \\((\\mathbf{R}^2)\\), and Pearson Correlation Coefficient (Corr), for comparative evaluation. Notably, a lower value of RMSE or a higher value of \\(\\mathbf{R}^2\\) (or Corr) indicates better performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.894, + 0.901 + ], + "angle": 0, + "content": "Model Size. Our proposed MMST-ViT builds on the top of Vision Transformer (ViT) [12]. Similar to ViT, it consists of a stack of Transformer blocks [50], where each Transformer block includes a Multi-Head Attention (MHA) block and" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5779" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.351, + 0.09, + 0.619, + 0.105 + ], + "angle": 0, + "content": "Table 2: Model details used in our study" + }, + { + "type": "table", + "bbox": [ + 0.09, + 0.113, + 0.88, + 0.179 + ], + "angle": 0, + "content": "
ModelLayerHidden SizeHeadMLP SizeOthers
Multi-Modal TransformerPVT-T/4{2, 2, 2, 2}{64, 128, 320, 512}{1, 2, 5, 8}{512, 1024, 1280, 2048}SR Ratios = {8, 4, 2, 1}
MM-MHA251282048Context Size = 9
Spatial TransformerS-MHA451232048-
Temporal TransformerT-MHA451232048Context Size = 9
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.188, + 0.893, + 0.219 + ], + "angle": 0, + "content": "Table 3: Overall comparative crop yield predictions for 2021, with the best results shown in bold. Cotton yields are measured in pounds per acre (LB/AC), whereas other crop yields are measured in bushels per acre (BU/AC)" + }, + { + "type": "table", + "bbox": [ + 0.092, + 0.222, + 0.88, + 0.312 + ], + "angle": 0, + "content": "
MethodCornCottonSoybeanWinter Wheat
RMSE (↓)R2(↑)Corr (↑)RMSE (↓)R2(↑)Corr (↑)RMSE (↓)R2(↑)Corr (↑)RMSE (↓)R2(↑)Corr (↑)
ConvLSTM18.60.6110.78265.40.7150.8467.20.6160.7857.40.5110.715
CNN-RNN14.60.7050.83969.50.6530.8085.80.7030.8397.50.6140.783
GNN-RNN14.20.7300.85458.50.6470.8045.40.7480.8656.00.6210.788
Ours10.50.8110.90042.40.7900.8893.90.8430.9184.60.7850.886
" + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.328, + 0.471, + 0.493 + ], + "angle": 0, + "content": "an MLP block, and both of which incorporate the LayerNorm [4] for normalization. Table 2 presents the details of model sizes used in our experiments. Note that \"PVT-T/4\" refers to the PVT-Tiny model with a patch size of 4, and \"SR Ratios\" represents the spatial reduction ratio in PVT. Following the original PVT [51], we divide the PVT backbone into four stages and report the corresponding model sizes at each stage in the second row of Table 2. The other transformers are single-stage, similar to the vanilla ViT [12]. Notably, \"Context Size\" represents the number of meteorological parameters used in our study." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.5, + 0.47, + 0.681 + ], + "angle": 0, + "content": "Hyperparameters. Our model is pre-trained for 200 epochs using AdamW [35] with \\(\\beta_{1} = 0.9\\), \\(\\beta_{2} = 0.95\\), a weight decay of 0.05, and a cosine decay schedule [34] with an initial learning rate of \\(1e - 4\\), and warmup epochs of 20. To perform data augmentation for pre-training, various techniques such as random cropping, random horizontal flipping, random Gaussian blur, and color jittering are employed. These techniques are similar to those used in SimCLR [9]. After pre-training, we fine-tune our proposed MMST-ViT for 100 epochs using AdamW with \\(\\beta_{1} = 0.9\\), \\(\\beta_{2} = 0.999\\), a cosine decay schedule with an initial learning rate of \\(1e - 3\\), and warmup epochs of 5." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.694, + 0.406, + 0.71 + ], + "angle": 0, + "content": "5.2. Comparative Performance Evaluation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.718, + 0.47, + 0.779 + ], + "angle": 0, + "content": "We conduct experiments for predicting 2021 crop yields at the county level across four aforementioned U.S. states, with prediction performance measured by the three metrics of RMSE, \\( \\mathbf{R}^2 \\), and Corr." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Table 3 lists the comparative performance results of our MMST-ViT and its three counterparts, i.e., ConvLSTM, CNN-RNN, and GNN-RNN. Four observations are obtained from the table. First, our approach achieves the best performance under all metrics. In particular, for the soybean yield prediction, our approach achieves the lowest RMSE of 3.9 and the highest \\( R^2 \\) (or Corr) of 0.843 (or 0.918). With the lowest RMSE value, our predicted soybean" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.328, + 0.895, + 0.646 + ], + "angle": 0, + "content": "yields are the closest to the actual amounts. In addition, the highest \\(\\mathbb{R}^2\\) and Corr values demonstrate that our predicted soybean yields are best correlated to actual figures. Second, our approach significantly outperforms ConvLSTM, with its RMSE values always lower than those of ConvLSTM markedly, ranging from 2.8 (for winter wheat) to 23.0 (for cotton). The reason is that ConvLSTM overlooks the impact of meteorological parameters on crop growth. Third, CNN-RNN underperforms our approach by 4.1 (for corn), by 27.1 (for cotton), by 1.9 (for soybean), and by 2.9 (for winter wheat), in terms of RMSE, though both models take into account the effect of long-term climate change on crop yields. Because CNN-RNN cannot model the spatial dependency among neighborhood regions. Fourth, MMST-ViT outperforms the most recent state-of-the-art (i.e., GNN-RNN) measurably. Specifically, our RMSE value is lower by 16.1 for cotton, whereas our \\(\\mathbb{R}^2\\) and Corr values are better respectively by 0.165 and 0.098 for winter wheat. These results are contributed by leveraging both visual remote sensing and numerical meteorological data in our model, while GNN-RNN only considers the meteorological data." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.663, + 0.851, + 0.68 + ], + "angle": 0, + "content": "5.3. Visualizing Crop Yield Prediction Errors" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.69, + 0.895, + 0.901 + ], + "angle": 0, + "content": "In this section, we conduct experiments to visualize crop yield prediction errors across four U.S. states: Mississippi (MS), Louisiana (LA), Iowa (IA), and Illinois (IL). We use the same experimental settings as those stated in Section 5.2. Figure 4 shows the absolute prediction errors for soybean across counties/parishes in the four states, with navy blue and light blue respectively indicating the high and low absolute errors. Our MMST-ViT model is highly effective in predicting crop yields, with the absolute prediction errors of \\(57.2\\%\\) counties below 3 BU/AC. Furthermore, we discover that \\(95.1\\%\\) of counties in MS, \\(92.5\\%\\) of parishes in LA, \\(86.8\\%\\) of counties in IA, and \\(91.0\\%\\) of counties in IL achieve decent absolute prediction errors (i.e., \\(\\leq 6\\) BU/AC). These empirical findings validate the robustness of MMST-" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5780" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.117, + 0.089, + 0.273, + 0.202 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.116, + 0.209, + 0.241, + 0.224 + ], + "angle": 0, + "content": "(a) Mississippi (MS)" + }, + { + "type": "image", + "bbox": [ + 0.298, + 0.089, + 0.465, + 0.202 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.319, + 0.21, + 0.434, + 0.224 + ], + "angle": 0, + "content": "(b) Louisiana (LA)" + }, + { + "type": "image", + "bbox": [ + 0.479, + 0.09, + 0.663, + 0.202 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.535, + 0.21, + 0.615, + 0.223 + ], + "angle": 0, + "content": "(c) Iowa (IA)" + }, + { + "type": "image", + "bbox": [ + 0.711, + 0.09, + 0.862, + 0.202 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.727, + 0.21, + 0.819, + 0.223 + ], + "angle": 0, + "content": "(d) Illinois (IL)" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.235, + 0.894, + 0.267 + ], + "angle": 0, + "content": "Figure 4: Illustration of absolute prediction errors for soybean across four U.S. states. Note that a county/parish with \\(< 0\\) indicates its soybean yield data is unavailable." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.281, + 0.347, + 0.296 + ], + "angle": 0, + "content": "ViT across various geographic locations." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.304, + 0.455, + 0.319 + ], + "angle": 0, + "content": "5.4. Performance of One Year Ahead Predictions" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.328, + 0.47, + 0.584 + ], + "angle": 0, + "content": "In practice, predicting crop yields well in advance of harvest, can provide valuable information for farmers, agribusinesses, and governments in their agricultural planning and decision-making processes. This information can be used to elevate agricultural resilience and sustainability, make informed financial decisions, and support global food security [23]. A prior study [15] simulated the early prediction scenario by masking partial inputs, successfully making predictions several months before harvest. In this study, we attempt a step further by making crop yield predictions one year before the harvest. In particular, we leverage remote sensing and short-term meteorological data during the growing season in the current year to predict crop yields in the next year. For example, the Sentinel-2 imagery and daily HRRR data during the growing season in 2020 are utilized as remote sensing data and the short-term meteorological data for predicting crop yields in 2021." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.585, + 0.47, + 0.81 + ], + "angle": 0, + "content": "Figure 5 illustrates the experimental results. It is observed that our MMST-ViT outperforms three baseline models, i.e., ConvLSTM, CNN-RNN, and GNN-RNN, for the predictions of one year ahead. Among all crops, MMST-ViT achieves the lowest RMSE values ranging from 4.7 (for soybean) to 50.2 (for cotton), the highest \\(\\mathbb{R}^2\\) values ranging from 0.711 (for winter wheat) to 0.792 (for soybean), and the highest Corr values ranging from 0.843 (for winter wheat) to 0.890 (for soybean). Additionally, compared to its in-season prediction results (see the 6th row of Table 3), the one year ahead prediction outcomes of our approach are just slightly inferior, degraded respectively by \\(8.6\\%\\), of \\(15.5\\%\\), of \\(17.0\\%\\), and of \\(14.6\\%\\) in terms of RMSE for corn, cotton, soybean, and winter wheat. The empirical results confirm the robustness of MMST-ViT." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Interestingly, we also observe that the prediction results for the cotton have a high RMSE value but not a low \\( \\mathbb{R}^2 \\) (or Corr) value. This is because the cotton yield is measured by pounds per acre (LB/AC), with a high standard deviation value of 250.1, while other crop yields are measured by bushels per acre (BU/AC), with low standard deviation val" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.279, + 0.892, + 0.324 + ], + "angle": 0, + "content": "Table 4: Ablation studies for different components, with five scenarios considered and the last row listing the results of MMST-ViT" + }, + { + "type": "table", + "bbox": [ + 0.504, + 0.332, + 0.89, + 0.464 + ], + "angle": 0, + "content": "
ComponentCornSoybean
RMSE (↓)Corr (↑)RMSE (↓)Corr (↑)
Temporal Transformerw/o long-term14.50.8436.20.850
w/o T-MHA15.70.8205.60.839
Spatial Transformerw/o S-MHA13.50.8565.60.849
Multi-Modal Transformerw/o short-term13.60.8396.10.845
w/o image15.20.8096.80.822
MMST-ViT-10.50.9003.90.918
" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.482, + 0.892, + 0.543 + ], + "angle": 0, + "content": "ues (e.g., 11.8 for soybean). In scenarios with high variance data, the RMSE value may worsen due to larger residuals, while the \\(\\mathbf{R}^2\\) value improves due to the increased proportion of explained variance." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.554, + 0.665, + 0.569 + ], + "angle": 0, + "content": "5.5. Ablation Studies" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.583, + 0.892, + 0.839 + ], + "angle": 0, + "content": "Key Components. We next conduct experiments to show how each key component in our MMST-ViT affects prediction performance. Table 4 lists the results of our ablation studies under five different scenarios, with one shown in a row. Here, \"w/o long-term\" indicates masking the long-term meteorological data, and \"w/o T-MHA\" represents the absence of our Temporal Transformer and instead resorting to the average pooling to obtain the global temporal representation. Similarly, \"w/o S-MHA\" denotes utilizing the average pooling to obtain the global spatial representation. The scenarios of \"w/o short-term\" and \"w/o image\" represent respectively masking the short-term meteorological data and the remote sensing data from the Multi-Modal Transformer. Note that masking either data makes our model unable to conduct MM-MHA, following Eq. (1). The results of our complete MMST-ViT outcomes are shown in the last row of Table 4." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Three observations can be made from Table 4. First, the long-term meteorological data degrades the Corr value by 0.057 (or 0.068) for corn (or soybean). This validates that crop yield prediction accuracy can benefit from histori" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.514, + 0.957 + ], + "angle": 0, + "content": "5781" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.09, + 0.327, + 0.228 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.171, + 0.238, + 0.234, + 0.251 + ], + "angle": 0, + "content": "(a) RMSE" + }, + { + "type": "image", + "bbox": [ + 0.342, + 0.09, + 0.589, + 0.23 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.445, + 0.237, + 0.486, + 0.251 + ], + "angle": 0, + "content": "(b) \\(\\mathbf{R}^2\\)" + }, + { + "type": "image", + "bbox": [ + 0.607, + 0.091, + 0.852, + 0.23 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.704, + 0.238, + 0.754, + 0.251 + ], + "angle": 0, + "content": "(c) Corr" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.257, + 0.892, + 0.289 + ], + "angle": 0, + "content": "Figure 5: Illustration of the performance for predictions of one year ahead under (a) RMSE, (b) \\( \\mathbb{R}^2 \\), and (c) Corr, with the cotton yield measured by LB/AC and other crop yields measured by BU/AC." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.302, + 0.471, + 0.484 + ], + "angle": 0, + "content": "ical meteorological data, which dictates long-term climate change. Second, the absence of either the Temporal Transformer or the Spatial Transformer lowers the Corr value by 0.080 (for corn) and by 0.069 (for soybean), respectively. Third, unable to conduct MM-MHA as the result of masking the short-term meteorological data or the satellite images degrades prediction performance greatly. For example, masking the short-term meteorological data (or satellite images) causes the Corr value degradation by 0.096 (or 0.073) for soybean. This statistical evidence exhibits the importance of our Multi-Modal Transformer for capturing the impact of meteorological parameters on crop growth." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.494, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Pre-training Techniques. We conduct experiments to explore the impact of our proposed multi-modal self-supervised pre-training, i.e., Eq. (2), on the crop yield prediction. We consider three scenarios, i.e., MMST-ViT without pre-training, with the pre-training technique described in SimCLR [9], and with our multi-modal pre-training. Table 5 presents the prediction performance outcomes. The table reveals that our MMST-ViT (w/ our multi-modal pretraining) significantly outperforms its counterpart (w/o pretraining), exhibiting a lower RMSE value by 2.7 (or 1.2) and a larger Corr value by 0.043 (or 0.043) for corn (or soybean), due to two reasons. First, Vision Transformer (ViT)-based models are prone to overfitting [12], but our multi-modal self-supervised learning can significantly mitigate this issue by leveraging both visual remote sensing data and numerical meteorological data for pre-training. Second, our multi-modal self-supervised pre-training may can capture the impact of meteorological parameters on the crops. In contrast, pre-training our MMST-ViT with the SimCLR technique only achieves marginal performance improvement (compared to the one w/o pre-training), achieving the Corr improvement of 0.001 (0.875 v.s. 0.876) for soybean. This is because the SimCLR technique fails to leverage numerical meteorological parameters for pre-training. These empirical results validate the necessity and importance of our proposed multi-modal pre-training for accurate crop yield predictions." + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.3, + 0.892, + 0.331 + ], + "angle": 0, + "content": "Table 5: Ablation studies for different pre-training techniques, with three scenarios considered" + }, + { + "type": "table", + "bbox": [ + 0.504, + 0.338, + 0.89, + 0.412 + ], + "angle": 0, + "content": "
MethodCornSoybean
RMSE (↓)Corr (↑)RMSE (↓)Corr (↑)
w/o pretraining13.20.8575.10.875
w/ SimCLR12.90.8574.90.876
w/ multi-modal pretraining10.50.9003.90.918
" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.428, + 0.618, + 0.443 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.456, + 0.892, + 0.758 + ], + "angle": 0, + "content": "This paper has proposed the Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), a climate change-aware deep learning approach for predicting crop yields at the county level across the United States. MMST-ViT comprises three key components of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer. Three innovative Multi-Head Attention (MHA) mechanisms are introduced, one for each component. As a result, our MMST-ViT can leverage both the visual remote sensing data and the numerical meteorological data for capturing the impact of short-term growing season weather variations and long-term climate change on crop yields. Additionally, a novel multi-modal contrastive learning technique has been developed, able to effectively pre-train our model without the need of human supervision. We have conducted extensive experiments on \\(200+\\) counties/parishes located in 4 U.S. states, with the results demonstrating that our proposed MMST-ViT substantially outperforms its state-of-the-art counterparts consistently under three performance metrics of interest." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.782, + 0.659, + 0.799 + ], + "angle": 0, + "content": "Acknowledgments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.892, + 0.902 + ], + "angle": 0, + "content": "This work was supported in part by NSF under Grants 2019511, 2146447, and in part by the BoRSF under Grants LEQSF(2019-22)-RD-A-21 and LEQSF(2021-22)-RD-D-07. Any opinion and findings expressed in the paper are those of the authors and do not necessarily reflect the view of funding agencies." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5782" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.47, + 0.171 + ], + "angle": 0, + "content": "[1] Faezeh Akhavizadegan, Javad Ansarifar, Lizhi Wang, Isaiah Huber, and Sotirios V Archontoulis. A time-dependent parameter estimation framework for crop modeling. Scientific reports, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.173, + 0.468, + 0.214 + ], + "angle": 0, + "content": "[2] Javad Ansarifar, Lizhi Wang, and Sotirios V Archontoulis. An interaction regression model for crop yield prediction. Scientific reports, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.217, + 0.469, + 0.272 + ], + "angle": 0, + "content": "[3] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In International Conference on Computer Vision (ICCV), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.274, + 0.469, + 0.314 + ], + "angle": 0, + "content": "[4] Jimmy Lei Ba, Jamie Ryan Kiros, and Geoffrey E Hinton. Layer normalization. arXiv preprint arXiv:1607.06450, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.318, + 0.469, + 0.358 + ], + "angle": 0, + "content": "[5] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. Beit: BERT pre-training of image transformers. In International Conference on Learning Representations (ICLR), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.361, + 0.469, + 0.43 + ], + "angle": 0, + "content": "[6] Hangbo Bao, Li Dong, Furu Wei, Wenhui Wang, Nan Yang, Xiaodong Liu, Yu Wang, Jianfeng Gao, Songhao Piao, Ming Zhou, and Hsiao-Wuen Hon. Unilmv2: Pseudo-masked language models for unified language model pre-training. In International Conference on Machine Learning (ICML), 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.433, + 0.468, + 0.487 + ], + "angle": 0, + "content": "[7] Mathilde Caron, Hugo Touvron, Ishan Misra, Hervé Jégou, Julien Mairal, Piotr Bojanowski, and Armand Joulin. Emerging properties in self-supervised vision transformers. In International Conference on Computer Vision (ICCV), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.49, + 0.469, + 0.544 + ], + "angle": 0, + "content": "[8] Liyan Chen, Weihan Wang, and Philippos Mordohai. Learning the distribution of errors in stereo matching for joint disparity and uncertainty estimation. In Computer Vision and Pattern Recognition (CVPR), 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.547, + 0.469, + 0.602 + ], + "angle": 0, + "content": "[9] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey E. Hinton. A simple framework for contrastive learning of visual representations. In International Conference on Machine Learning (ICML), 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.604, + 0.469, + 0.673 + ], + "angle": 0, + "content": "[10] Minghan Cheng, Xiyun Jiao, Lei Shi, Josep Penuelas, Lalit Kumar, Chenwei Nie, Tianao Wu, Kaihua Liu, Wenbin Wu, and Xiuliang Jin. High-resolution crop yield and water productivity dataset generated using random forest and remote sensing. Scientific Data, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.676, + 0.469, + 0.731 + ], + "angle": 0, + "content": "[11] Karine Chenu, John Roy Porter, Pierre Martre, Bruno Basso, Scott Cameron Chapman, Frank Ewert, Marco Bindi, and Senthold Asseng. Contribution of crop models to adaptation in wheat. Trends in plant science, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.733, + 0.469, + 0.829 + ], + "angle": 0, + "content": "[12] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations (ICLR), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.832, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[13] Nicola Falco, Haruko M Wainwright, Baptiste Dafflon, Craig Ulrich, Florian Soom, John E Peterson, James Bentley Brown, Karl B Schaettle, Malcolm Williamson, Jackson D Cothren, et al. Influence of soil heterogeneity on soybean plant development and crop yield evaluated using time-series" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "of uav and ground-based geophysical imagery. Scientific reports, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.122, + 0.892, + 0.176 + ], + "angle": 0, + "content": "[14] Haoqi Fan, Bo Xiong, Karttikeya Mangalam, Yanghao Li, Zhicheng Yan, Jitendra Malik, and Christoph Feichtenhofer. Multiscale vision transformers. In International Conference on Computer Vision (ICCV), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.179, + 0.892, + 0.233 + ], + "angle": 0, + "content": "[15] Joshua Fan, Junwen Bai, Zhiyun Li, Ariel Ortiz-Bobea, and Carla P. Gomes. A GNN-RNN approach for harnessing geospatial and temporal information: Application to crop yield prediction. In AAAI, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.235, + 0.892, + 0.289 + ], + "angle": 0, + "content": "[16] Niketa Gandhi, Owaiz Petkar, and Leisa J Armstrong. Rice crop yield prediction using artificial neural networks. In 2016 IEEE Technological Innovations in ICT for Agriculture and Rural Development (TIAR), 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.291, + 0.892, + 0.346 + ], + "angle": 0, + "content": "[17] Vivien Sainte Fare Garnot and Loic Landrieu. Panoptic segmentation of satellite image time series with convolutional temporal attention networks. In International Conference on Computer Vision (ICCV), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.348, + 0.892, + 0.402 + ], + "angle": 0, + "content": "[18] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross B. Girshick. Masked autoencoders are scalable vision learners. In Conference on Computer Vision and Pattern Recognition (CVPR), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.404, + 0.892, + 0.445 + ], + "angle": 0, + "content": "[19] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Conference on Computer Vision and Pattern Recognition (CVPR), 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.447, + 0.892, + 0.487 + ], + "angle": 0, + "content": "[20] Yi He, Fudong Lin, Xu Yuan, and Nian-Feng Tzeng. Interpretable minority synthesis for imbalanced classification. In IJCAI, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.49, + 0.892, + 0.544 + ], + "angle": 0, + "content": "[21] Byeongho Heo, Sangdoo Yun, Dongyoon Han, Sanghyuk Chun, Junsuk Choe, and Seong Joon Oh. Rethinking spatial dimensions of vision transformers. In International Conference on Computer Vision (ICCV), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.546, + 0.892, + 0.573 + ], + "angle": 0, + "content": "[22] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 1997." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.575, + 0.89, + 0.602 + ], + "angle": 0, + "content": "[23] Takeshi Horie, Masaharu Yajima, and Hiroshi Nakagawa. Yield forecasting. Agricultural systems, 1992." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.604, + 0.856, + 0.617 + ], + "angle": 0, + "content": "[24] HRRR. The high-resolution rapid refresh (hrrr), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.619, + 0.892, + 0.701 + ], + "angle": 0, + "content": "[25] James W Jones, John M Antle, Bruno Basso, Kenneth J Boote, Richard T Conant, Ian Foster, H Charles J Godfray, Mario Herrero, Richard E Howitt, Sander Janssen, et al. Toward a new generation of agricultural system data, models, and knowledge products: State of agricultural systems science. Agricultural systems, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.703, + 0.892, + 0.744 + ], + "angle": 0, + "content": "[26] Saeed Khaki, Hieu Pham, and Lizhi Wang. Simultaneous corn and soybean yield prediction from remote sensing data using deep transfer learning. Scientific Reports, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.746, + 0.892, + 0.773 + ], + "angle": 0, + "content": "[27] Saeed Khaki and Lizhi Wang. Crop yield prediction using deep neural networks. Frontiers in plant science, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.775, + 0.892, + 0.814 + ], + "angle": 0, + "content": "[28] Saeed Khaki, Lizhi Wang, and Sotirios V Archontoulis. A cnn-rnn framework for crop yield prediction. Frontiers in Plant Science, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.817, + 0.892, + 0.871 + ], + "angle": 0, + "content": "[29] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E. Hinton. Imagenet classification with deep convolutional neural networks. In Neural Information Processing Systems (NeurIPS), 2012." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.873, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[30] Zhengfeng Lai, Sol Vesdapunt, Ning Zhou, Jun Wu, Cong Phuoc Huynh, Xuelu Li, Kah Kuen Fu, and Chen-Nee" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.515, + 0.957 + ], + "angle": 0, + "content": "5783" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.134 + ], + "angle": 0, + "content": "Chuah. Padclip: Pseudo-labeling with adaptive debiasing in clip for unsupervised domain adaptation. In International Conference on Computer Vision (ICCV), 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.47, + 0.205 + ], + "angle": 0, + "content": "[31] Yanghao Li, Chao-Yuan Wu, Haoqi Fan, Karttikeya Mangalam, Bo Xiong, Jitendra Malik, and Christoph Feichtenhofer. Mvitv2: Improved multiscale vision transformers for classification and detection. In Computer Vision and Pattern Recognition (CVPR), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.207, + 0.47, + 0.261 + ], + "angle": 0, + "content": "[32] Fudong Lin, Xu Yuan, Lu Peng, and Nian-Feng Tzeng. Cascade variational auto-encoder for hierarchical disentangle-. ment. In Conference on Information & Knowledge Management (CIKM), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.264, + 0.47, + 0.319 + ], + "angle": 0, + "content": "[33] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In International Conference on Computer Vision (ICCV), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.321, + 0.47, + 0.361 + ], + "angle": 0, + "content": "[34] Ilya Loshchilov and Frank Hutter. SGDR: stochastic gradient descent with warm restarts. In International Conference on Learning Representations (ICLR), 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.363, + 0.47, + 0.403 + ], + "angle": 0, + "content": "[35] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In International Conference on Learning Representations, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.406, + 0.47, + 0.447 + ], + "angle": 0, + "content": "[36] Spyridon Mourtzinis, Paul D Esker, James E Specht, and Shawn P Conley. Advancing agricultural research using machine learning algorithms. Scientific reports, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.449, + 0.47, + 0.531 + ], + "angle": 0, + "content": "[37] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, Gretchen Krueger, and Ilya Sutskever. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning (ICML), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.533, + 0.47, + 0.601 + ], + "angle": 0, + "content": "[38] Colin Raffel, Noam Shazeer, Adam Roberts, Katherine Lee, Sharan Narang, Michael Matena, Yanqi Zhou, Wei Li, and Peter J Liu. Exploring the limits of transfer learning with a unified text-to-text transformer. The Journal of Machine Learning Research, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.604, + 0.47, + 0.673 + ], + "angle": 0, + "content": "[39] David Rolnick, Priya L Donti, Lynn H Kaack, Kelly Kochanski, Alexandre Lacoste, Kris Sankaran, Andrew Slavin Ross, Nikola Milojevic-Dupont, Natasha Jaques, Anna Waldman-Brown, et al. Tackling climate change with machine learning. ACM Computing Surveys (CSUR), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.675, + 0.47, + 0.73 + ], + "angle": 0, + "content": "[40] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Conference on Computer Vision and Pattern Recognition (CVPR), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.732, + 0.384, + 0.744 + ], + "angle": 0, + "content": "[41] Sentinel-Hub. Sentinel hub process api, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.746, + 0.47, + 0.801 + ], + "angle": 0, + "content": "[42] Mohsen Shahhosseini, Guiping Hu, Isaiah Huber, and Sotirios V Archontoulis. Coupling machine learning and crop modeling improves crop yield prediction in the us corn belt. Scientific reports, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.803, + 0.47, + 0.871 + ], + "angle": 0, + "content": "[43] Xingjian Shi, Zhourong Chen, Hao Wang, Dit-Yan Yeung, Wai-Kin Wong, and Wang-chun Woo. Convolutional LSTM network: A machine learning approach for precipitation nowcasting. In Neural Information Processing Systems (NeurIPS), 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.874, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[44] Fulu Tao, Masayuki Yokozawa, and Zhao Zhang. Modelling the impacts of weather and climate variability on crop pro" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "ductivity over a large area: a new process-based model development, optimization, and uncertainties analysis. agricultural and forest meteorology, 2009." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[45] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. VideoMAE: Masked autoencoders are data-efficient learners for self-supervised video pre-training. In Neural Information Processing Systems (NeurIPS), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.192, + 0.892, + 0.261 + ], + "angle": 0, + "content": "[46] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Hervé Jégou. Training data-efficient image transformers & distillation through attention. In Marina Meila and Tong Zhang, editors, International Conference on Machine Learning (ICML), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.263, + 0.892, + 0.317 + ], + "angle": 0, + "content": "[47] Gabriel Tseng, Ivan Zvonkov, Catherine Nakalembe, and Hannah Kerner. Cropharvest: a global satellite dataset for crop type classification. Neural Information Processing Systems (NeurIPS), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.319, + 0.892, + 0.387 + ], + "angle": 0, + "content": "[48] Matteo Turchetta, Luca Corinzia, Scott Sussex, Amanda Burton, Juan Herrera, Ioannis N Athanasiadis, Joachim M Buhmann, and Andreas Krause. Learning long-term crop management strategies with cyclesgym. In Neural Information Processing Systems (NeurIPS), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.389, + 0.892, + 0.414 + ], + "angle": 0, + "content": "[49] USDA. The united states department of agriculture (usda), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.418, + 0.892, + 0.472 + ], + "angle": 0, + "content": "[50] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Neural Information Processing Systems (NeurIPS), 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.474, + 0.892, + 0.543 + ], + "angle": 0, + "content": "[51] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In International Conference on Computer Vision (ICCV), pages 548-558, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.545, + 0.892, + 0.599 + ], + "angle": 0, + "content": "[52] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. PVT v2: Improved baselines with pyramid vision transformer. Comput. Vis. Media, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.601, + 0.892, + 0.669 + ], + "angle": 0, + "content": "[53] Xiaocui Wu, Xiangming Xiao, Jean Steiner, Zhengwei Yang, Yuanwei Qin, and Jie Wang. Spatiotemporal changes of winter wheat planted and harvested areas, photosynthesis and grain production in the contiguous united states from 2008-2018. Remote Sensing, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.671, + 0.892, + 0.754 + ], + "angle": 0, + "content": "[54] Rongting Xu, Hanqin Tian, Shufen Pan, Stephen A Prior, Yucheng Feng, William D Batchelor, Jian Chen, and Jia Yang. Global ammonia emissions from synthetic nitrogen fertilizer applications in agricultural systems: Empirical and process-based estimates and uncertainty. *Global change biology*, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.755, + 0.892, + 0.823 + ], + "angle": 0, + "content": "[55] Li Yuan, Yunpeng Chen, Tao Wang, Weihao Yu, Yujun Shi, Zihang Jiang, Francis E. H. Tay, Jiashi Feng, and Shuicheng Yan. Tokens-to-token vit: Training vision transformers from scratch onImagenet. In International Conference on Computer Vision (ICCV), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.825, + 0.892, + 0.894 + ], + "angle": 0, + "content": "[56] Yihe Zhang, Xu Yuan, Sytske K. Kimball, Eric Rappin, Li Chen, Paul J. Darby III, Tom Johnsten, Lu Peng, Boisy Pitre, David Bourrie, and Nian-Feng Tzeng. Precise weather parameter predictions for target regions via neural networks. In ECML-PKDD. Applied Data Science Track, 2021." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.894 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5784" + } + ] +] \ No newline at end of file diff --git a/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/8b54a15b-f3ee-46da-88b3-5c8950b9cb49_origin.pdf b/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/8b54a15b-f3ee-46da-88b3-5c8950b9cb49_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..908ca346be82191779c2a944c567e18bc8fb5c71 --- /dev/null +++ b/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/8b54a15b-f3ee-46da-88b3-5c8950b9cb49_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:0d90eaf034e8d1c80a5c79e32ea6b95ceb39d76b88ef2831f3145557cf2b85c8 +size 13376213 diff --git a/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/full.md b/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/full.md new file mode 100644 index 0000000000000000000000000000000000000000..e9f15a0a7613d151e01271fac01001cb9996bf32 --- /dev/null +++ b/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/full.md @@ -0,0 +1,324 @@ +# MMST-ViT: Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer + +Fudong Lin $^{1}$ , Summer Crawford $^{2}$ , Kaleb Guillot $^{2}$ , Yihe Zhang $^{2}$ , Yan Chen $^{3}$ , Xu Yuan $^{1*}$ , Li Chen $^{2}$ , Shelby Williams $^{2}$ , Robert Minvielle $^{2}$ , Xiangming Xiao $^{4}$ , Drew Gholson $^{5}$ , Nicolas Ashwell $^{5}$ , Tri Setiyono $^{6}$ , Brenda Tubana $^{7}$ , Lu Peng $^{8}$ , Magdy Bayoumi $^{2}$ , Nian-Feng Tzeng $^{2}$ $^{1}$ University of Delaware, $^{2}$ University of Louisiana at Lafayette, $^{3}$ University of Connecticut, $^{4}$ University of Oklahoma, $^{5}$ Mississippi State University, $^{6}$ Louisiana State University, $^{7}$ LSU AgCenter, $^{8}$ Tulane University + +# Abstract + +Precise crop yield prediction provides valuable information for agricultural planning and decision-making processes. However, timely predicting crop yields remains challenging as crop growth is sensitive to growing season weather variation and climate change. In this work, we develop a deep learning-based solution, namely Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), for predicting crop yields at the county level across the United States, by considering the effects of short-term meteorological variations during the growing season and the long-term climate change on crops. Specifically, our MMST-ViT consists of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer. The Multi-Modal Transformer leverages both visual remote sensing data and short-term meteorological data for modeling the effect of growing season weather variations on crop growth. The Spatial Transformer learns the high-resolution spatial dependency among counties for accurate agricultural tracking. The Temporal Transformer captures the long-range temporal dependency for learning the impact of long-term climate change on crops. Meanwhile, we also devise a novel multi-modal contrastive learning technique to pre-train our model without extensive human supervision. Hence, our MMST-ViT captures the impacts of both short-term weather variations and long-term climate change on crops by leveraging both satellite images and meteorological data. We have conducted extensive experiments on over 200 counties in the United States, with the experimental results exhibiting that our MMST-ViT outperforms its counterparts under three performance metrics of interest. Our dataset and code are available at https://github.com/fudong03/MMST-ViT. + +# 1. Introduction + +Accurate crop yield prediction is essential for agricultural planning and advisory processes [26], informed economic decisions [2], and global food security [36]. However, predicting crop yields precisely is challenging as it requires to consider the effects of i) short-term weather variations, governed by the meteorological data during the growing season, and ii) long-term climate change, governed by historical meteorological factors, on crops simultaneously. Meanwhile, precise crop tracking relies on high-resolution remote sensing data. While process-based prediction approaches [44, 11, 25, 54] exist, they often suffer from high inaccuracies due to their strong assumptions on management practices [15]. On the other hand, motivated by the recent success of deep neural networks [29, 19, 50, 12, 20, 56, 37, 32, 18, 30, 8], deep learning (DL)-based methods have been widely adopted for crop yield predictions, due to their effectiveness in accurate agricultural tracking [27, 26] and their potent capabilities in capturing the spatial and temporal variation of meteorological data [28, 15]. + +So far, DL-based solutions for crop yield predictions can be roughly grouped into two categories, i.e., remote sensing data-based and meteorological data-based approaches. The former [27, 26, 53, 13, 17, 47, 10] employs such remote sensing data as satellite images, unmanned aerial vehicle (UAV)-based imagery data, or vegetation indices to estimate the annual crop yield, while the latter [16, 1, 36, 42, 48] predicts the crop yield by using meteorological parameter data, including temperature, precipitation, vapor pressure deficit, etc. However, the former overlooks the direct impact of meteorological parameters on crop growth, while the latter lacks high-resolution remote sensing data for accurate agricultural tracking. + +A recent study [39] has reported that the long-term climate change would gradually decrease the crop yield. + +Driven by this discovery, follow-up pursuits have attempted to explore the effect of long-term climate change on crops. For example, the CNN-RNN model [28] demonstrates that the crop yield prediction can benefit from historical meteorological data, which is essential for measuring the impacts of climate change. Later, GNN-RNN [15] extends CNN-RNN by framing the crop yield prediction as the Spatial-Temporal forecasting problem. It employs Graph Neural Networks (GNN) and Long Short-Term Memory (LSTM) [22] respectively for learning spatial dependency among neighborhood counties and for capturing the impact of long-term meteorological data on crops. However, both of them only take into account the meteorological data for predictions, failing to leverage the remote sensing data for accurate agricultural tracking. + +In this work, we aim to develop a new DL-based solution for predicting crop yields at the county level across the United States, by using both visual remote sensing data (from the Sentinel-2 satellite imagery [41]) and numerical meteorological data (from the HRRR model [24]). Our solution has two main goals. First, it captures the impacts of both short-term growing season weather variations and long-term climate change on crops. Second, it aims to leverage high-resolution remote sensing data for accurate agricultural tracking. To achieve our goals, we propose the Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), motivated by the recent success of Vision Transformers (ViT) [12]. To the best of our knowledge, MMST-ViT is the first ViT-based model for real-world crop yield prediction. It advances previous CNN/GNN-based and RNN-based counterparts respectively with better generalization to the multi-model data and with more powerful abilities in capturing long-term temporal dependency. Its three components of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer are each equipped with one novel Multi-Head Attention (MHA) mechanism [50]. Specifically, the Multi-Modal Transformer leverages satellite images and meteorological data during the growing season for capturing the direct impact of short-term weather variations on crop growth. The Spatial Transformer learns high-resolution spatial dependency among counties for precise crop tracking. The Temporal Transformer captures the effects of long-term climate change on crops. Since ViT-based models are prone to overfitting [12], we also develop a novel multi-modal contrastive learning technique that pre-trains our Multi-Modal Transformer without requiring human supervision. We have conducted experiments on over 200 counties in the United States. The experimental results exhibit that our MMST-ViT outperforms its state-of-the-art counterparts under three performance metrics of interest. For example, on the soybean prediction, our MMST-ViT achieves the lowest Root Mean Square Error (RMSE) value of 3.9, the highest R + +squared $(\mathbb{R}^2)$ value of 0.843, and the best Pearson Correlation Coefficient (Corr) value of 0.918. + +# 2. Related Work + +Vision Transformers. Adopted from Transformers [50] in natural language processing, Vision Transformers (ViT) have exhibited commendable performance in various computer vision tasks. The original ViT [12] first partitions an image into a set of image patches, then applies Multi-Head Attention (MHA) [50] over the patches, and finally utilizes a learnable classification token to capture global visual representation for image classification. Several subsequent methods have been developed, including DeiT [46] for data-efficient ViT through knowledge distillation, Swin [33] for computation-efficient ViT using shifted windows, PVT [51] for dense prediction tasks, and MAE [18] for self-supervised learning, among others [7, 21, 14, 55, 3, 52, 31, 45]. However, applying prior ViT approaches to real-world crop yield prediction is challenging due to its needs of addressing the multi-modal inputs, of learning high-resolution spatial dependency, and of capturing long-range temporal dependency. Our work, based on ViT, advances existing methods by proposing three novel Multi-Head Attention (MHA) mechanisms respectively for leveraging both visual remote sensing data and numerical meteorological data, learning global spatial representation from multiple high-resolution data, and capturing the global temporal representation for measuring the long-term climate change effect. Additionally, we develop a new multi-modal contrastive learning technique to pre-train our multi-modal model for better prediction performance. + +Deep Learning (DL) for Crop Yield Prediction. DL has been widely adopted for real-world crop yield predictions. Such prediction studies can be grouped into two categories: remote sensing data-based and meteorological data-based approaches. The former uses satellite images, unmanned aerial vehicle (UAV) data, or vegetation indices to estimate crop yields. Its prominent studies include the use of UAV-acquired RGB images [27] for predicting in-season crop yields, YieldNet [26] which resorts to transfer learning for simultaneously estimating the yields of multiple crop types, among many others [53, 13, 17, 47, 10]. By contrast, the latter utilizes deep neural networks (DNNs) to capture the impact of meteorological parameters on crop yields, including CNN-RNN [28] which incorporates long-term meteorological data, GNN-RNN [15] which extends CNN-RNN by using Graph Neural Networks (GNN) for learning spatial information, and others [16, 1, 36, 42, 48]. However, the remote sensing data-based solutions overlook the impact of meteorological parameters on crops, while the meteorological data-based solutions often fail to incorporate the remote sensing data, known to be crucial for accurate agricultural + +Table 1: Overview of USDA Crop Dataset and HRRR Computed Dataset + +
DatasetParameters
USDAProduction, Yield
HRRRAveraged Temperature, Maximal Temperature, Minimal Temperature, Precipitation, Relative Humidity, Wind Gust, Wind Speed, Downward Shortwave Radiation Flux, Vapor Pressure Deficit
+ +tracking. Our work differs from prior studies in two aspects. First, it leverages both remote sensing data and meteorological data for capturing the impacts of both short-term growing season meteorological variations and the long-term climate change on crops. Second, it is the first to use Vision Transformers for crop yield predictions, advancing previous CNN/GNN- and RNN-based models respectively with better generalization to multi-modal data and with higher abilities for capturing long ranges of temporal dependency. + +# 3. Datasets + +In this study, we utilize three types of data for accurate county-level crop yield predictions: i) crop data from the United States Department of Agriculture (USDA), ii) meteorological data from the High-Resolution Rapid Refresh (HRRR), and iii) remote sensing data from the Sentinel-2 satellite, as outlined below. + +USDA Crop Dataset. The dataset, sourced from the United States Department of Agriculture (USDA) [49], provides annual crop data for major crops grown in the United States (U.S.), including corn, cotton, soybean, winter wheat, etc., on a county-level basis. It covers crop information such as production and yield from 2017 to 2022 (as listed in the second row of Table 1). + +HRRR Computed Dataset. The dataset, obtained from the High-Resolution Rapid Refresh atmospheric model (HRRR) [24], provides high-resolution meteorological data for the contiguous U.S. continent. It covers 9 weather parameters from 2017 to 2022 (see the third row in Table 1 for more information). + +Sentinel-2 Imagery. Sentinel-2 imagery is a set of images captured by the Sentinel-2 Earth observation satellite. It provides agriculture imagery for the contiguous U.S. continent from 2017 to 2022 with a 2-week interval. Since precise agricultural tracking requires high-resolution remote sensing data, the image of a county is partitioned into multiple fine-grained grids $(9 \times 9 \mathrm{~km})$ . Figure 1 shows an example of county partitioning. + +# 4. Method + +In this work, we aim to develop a deep learning (DL)-based model for predicting crop yields at the county level. Our goals are twofold. First, we plan to capture the mete + +![](images/a54ab7a758f291608607098d9237ba1146b2a18e99e9153ebcb5addbdf5ba50d.jpg) +(a) Grid Example + +![](images/dce3b4c54d71d6cf4be6283f648381fab365ad2cdc8561a66846f80a56ecd2b4.jpg) +(b) Sentinel-2 Imagery +Figure 1: Illustration of partitioning a county into multiple grids at the $9\mathrm{km}$ high-resolution. (a) An example of county partitioning, with the red line segments indicating the geometry boundary for the county and the blue line segments representing the high-resolution grids. (b) The resulting satellite images in the Sentinel-2 Imagery, with each composed of $384\times 384$ pixels, depicting an area of $9\times 9\mathrm{km}$ . + +orological effect, including growing season weather variations and climate change, on crop yields. Second, we aim to leverage high-resolution satellite images for precise agricultural tracking. The aforementioned three data sources are utilized for achieving our goals. + +# 4.1. Problem Statement + +We consider the combination of four types of data $(\boldsymbol{x},\boldsymbol{y}_s,\boldsymbol{y}_l,\boldsymbol{z})$ for predicting the crop yield at each single U.S. county. Specifically, $\boldsymbol{x} \in \mathbb{R}^{T \times G \times H \times W \times C}$ represents satellite images obtained from Sentinel-2 imagery, which capture the information of field crops on the ground. $T$ and $G$ indicate the numbers of temporal and spatial data, respectively, whereas $H$ , $W$ , and $C$ are the height, width, and number of channels in the satellite image. $\boldsymbol{y}_s \in \mathbb{R}^{T \times G \times N_1 \times d_y}$ and $\boldsymbol{y}_l \in \mathbb{R}^{T \times N_2 \times d_y}$ are meteorological parameters obtained from the HRRR dataset, representing the short-term and the long-term historical data, respectively. Here, $N_1$ and $N_2$ are the numbers of daily and monthly HRRR data points, respectively, and $d_y$ indicates the number of weather parameters. Note that the short-term meteorological data is the daily HRRR data during the growing season, while the long-term historical meteorological data is the monthly HRRR data from the past several years (e.g., 2018 to 2020 for predicting crop yields in 2021). $\boldsymbol{z} \in \mathbb{R}^{d_z}$ is the ground-truth crop information obtained from the USDA dataset, with $d_z$ representing the number of parameters for the crop data. + +# 4.2. Challenges + +Three challenges exist upon achieving our goals, outlined as follows. + +![](images/151c8dbafb88e4fed7282f7383b6312254dcc2ee892d00bba8f0323d7cc6bffc.jpg) +Figure 2: The architecture of our proposed MMST-ViT. + +Capturing the Effect of Growing Season Weather Variations on Crop Growth. Previous studies only consider the meteorological data (or the remote sensing data) for crop yield predictions, overlooking the direct impact of growing season weather variations on crop growth. To capture such an impact, we aim to leverage both visual remote sensing and numerical meteorological data. In particular, the Multi-Head Attention (MHA) technique [50] is adopted to capture the meteorological effects on crop growth. However, how to perform multi-modal attention over visual remote sensing data and numerical meteorological data remains open. + +Lacking a Mechanism for Pre-training Multi-Modal Model. Deep neural networks (DNNs), especially Vision Transformer (ViT)-based models, are prone to overfitting, requiring appropriate pre-training to achieve satisfactory performance. Unfortunately, conventional pretraining techniques (e.g., SimCLR [9]) only marginally improve crop yield prediction performance as they consider the visual data only, ineffective for pre-training multi-modal models. How to pre-train the multi-modal model for satisfactory crop yield predictions is challenging to be addressed. + +Capturing the Impact of Climate Change on Crops. As reported by a prior study [39], the long-term climate change in the atmosphere would gradually decrease the crop yield on the ground. Some studies [28, 15] have demonstrated that taking the climate change effect into account can better crop yield prediction. But their designs overlook the remote sensing data, viewed as essential for precise agricultural tracking. So far, how to develop effective ways to capture the impact of long-term climate change on crop yields + +is challenging and unanswered yet. + +# 4.3. Our Proposed Approach + +To tackle the aforementioned challenges, we develop the Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT) for predicting crop yields at the county level, by leveraging the remote sensing data and the short-term and long-term meteorological data. + +Model Overview. Our proposed MMST-ViT consists of three key components, i.e., Multi-Modal Transformer, Spatial Transformer, and Temporal Transformer, as shown in Figure 2. The Multi-Modal Transformer is designed to capture the impact of short-term meteorological variations on crop growth, by leveraging the satellite images (i.e., $\mathbf{x}$ ) and the short-term meteorological parameters (i.e., $\mathbf{y}_s$ ). The Spatial Transformer then utilizes the output of the Multi-Modal Transformer for learning the global spatial information of a county. Next, the Temporal Transformer combines the outputs of our Spatial Transformer and the long-term meteorological data (i.e., $\mathbf{y}_l$ ) to capture both global temporal information and the impact of long-term climate change on crop yields. Finally, the output of our Temporal Transformer is used by a linear classifier for predicting the annual crop yields. The details of each component are provided below. + +Multi-Modal Transformer. Aiming to capture the direct impact of atmospheric weather variations on crop growth, the Multi-Modal Transformer consists of a visual backbone network and a multi-modal attention layer. The former extracts high-quality visual representations from satellite images for accurate agricultural tracking, while the lat + +ter captures the relationship between the visual representation and meteorological parameters, to understand the impact of meteorological parameters on crop growth. Let $f_{\theta} \colon (\mathbb{R}^{T \times G \times H \times W \times C}, \mathbb{R}^{T \times G \times N_1 \times d_y}) \to \mathbb{R}^{T \times G \times d}$ be our Multi-Modal Transformer, with $\pmb{\theta}$ denoting the parameters for DNNs and $d$ representing the dimension for hidden vectors. Notably, all the hidden dimensions in this paper are set to the same size of $d$ . As such, the proposed Multi-Modal Transformer can be expressed as $f_{\theta}(x, y_s) = v_m$ , where $x$ and $y_s$ are the Sentinel-2 images and the short-term meteorological data, respectively. $v_m \in \mathbb{R}^{T \times G \times d}$ is the output of our Multi-Modal Transformer. + +In this work, we utilize Pyramid Vision Transformer (PVT) [51] as the visual backbone network since it advances ResNet [19] and vanilla ViT [12] respectively by having the global receptive field and by enabling high-resolution feature maps. To capture the direct impact of meteorological parameters on crop growth during the growing season, a naive way is by concatenating visual and numerical representations extracted respectively from the Sentinel-2 images and the meteorological parameters. Unfortunately, our empirical results show that such a naive way cannot achieve satisfactory performance. Inspired by the recent success of multi-head attention mechanisms [50, 12, 40], we devise a novel Multi-Modal Multi-Head Attention (MM-MHA) mechanism to capture the impact of meteorological parameters on crop growth, mathematically expressed as + +$$ +\operatorname {M M - M H A} (\boldsymbol {Q}, \boldsymbol {K}, \boldsymbol {V}) = \operatorname {S o f t m a x} (\boldsymbol {Q} \boldsymbol {K} ^ {T} / \sqrt {d}) \boldsymbol {V}, +$$ + +$$ +\boldsymbol {Q} = \boldsymbol {W} _ {m} ^ {Q} \cdot \varphi_ {m} (\boldsymbol {x}), \boldsymbol {K} = \boldsymbol {W} _ {m} ^ {K} \cdot \pi_ {m} (\boldsymbol {y} _ {s}), \tag {1} +$$ + +$$ +\boldsymbol {V} = \boldsymbol {W} _ {m} ^ {V} \cdot \pi_ {m} (\boldsymbol {y} _ {s}). +$$ + +Here, $\varphi_{m}(\pmb{x})\in \mathbb{R}^{T\times G\times N_{p}\times d}$ is the visual representation encoded by PVT, with $N_{p}$ indicating the number of image patches. $\pi_m(\pmb {y}_s)\in \mathbb{R}^{T\times G\times N_1\times d}$ is the meteorological parameters after the linear projection. Notably, $\pmb{W}_{m}^{Q},\pmb{W}_{m}^{K}$ , and $\pmb{W}_{m}^{V}$ are learnable projection matrices, similar to those in prior studies [50, 40]. To our knowledge, this is the first attempt at developing a multi-modal multi-attention approach for leveraging both visual remote sensing data and numerical meteorological data. + +However, ViT-based models are highly sensitive to overfitting, calling for pre-training with millions of visual data [12]. Meanwhile, real-world crop yield prediction usually lacks sufficient crop data for pre-training. Worse still, capturing the impact of short-term weather conditions on crops requires considering both the visual and the numerical data simultaneously. Although self-supervised learning techniques [9, 5, 18] have recently been developed for pretraining DNNs, they cannot tackle the aforementioned issue at the same time. For example, SimCLR [9] fails to address the multi-modal data issue. + +![](images/7b2afaaa406c86d2319c255b874242f1998dcb63b74f4614d577a37e2003a470.jpg) +Figure 3: Multi-modal self-supervised learning. + +Here, we propose a novel multi-modal self-supervised learning for pre-training our Multi-Modal Transformer without human supervision, which is inspired by SimCLR, but having two differences. First, we utilize the PVT instead of convolutional neural networks (CNNs) as the backbone network since PVT advances CNNs by having a global receptive field [51]. Second, we replace the Multi-Layer Perceptron (MLP) layer in SimCLR with our proposed multimodal self-attention layer (i.e., Eq. (1)) for simultaneously tackling visual and numerical data. Figure 3 illustrates its architecture. Given a satellite image $\pmb{x}^m$ (or $\pmb{x}^n$ ), we perform the data augmentation to get its two augmented images, and then feed them to the PVT to get two sets of visual representations. After that, we use our proposed MM-MHA (i.e., Eq. (1)) to perform multi-modal attention between the visual representations and the corresponding short-term parameters $\pmb{y}_s^m$ (or $\pmb{y}_s^n$ ), arriving at two sets of output sequences. Here, we regard two sets of output sequences out of a given satellite image (e.g., $\pmb{x}^m$ ) as the positive pair. Meanwhile, two sets of output sequences from different satellite images (e.g., $\pmb{x}^m$ and $\pmb{x}^n$ ) are regarded as the negative pair. Similar to vanilla ViT [12], the head of output sequences (i.e., the classification token) is taken as the output of our Multi-Modal Transformer, i.e., the hidden vector $\pmb{v}_m$ . As such, our multi-modal contrastive loss is defined as, + +$$ +\ell (i, j) = - \log \frac {\exp (\operatorname {s i m} \left(\boldsymbol {v} _ {m} ^ {i} , \boldsymbol {v} _ {m} ^ {j}\right) / \tau)}{\sum_ {i \neq k , k = 1 , \dots , 2 B} \exp (\operatorname {s i m} \left(\boldsymbol {v} _ {m} ^ {i} , \boldsymbol {v} _ {m} ^ {k}\right) / \tau)}, +$$ + +$$ +\mathcal {L} _ {\mathrm {c l}} = \frac {1}{2 B} \sum_ {k = 1} ^ {B} [ \ell (k, k + B) + \ell (k + B, k) ], \tag {2} +$$ + +where $B = T \times G$ . Here, $\pmb{v}_m^i$ and $\pmb{v}_m^j$ are the positive pair, and $\tau$ is the temperature parameter. Intuitively, our + +Eq. (2) encourages two hidden vectors from the same satellite image (i.e., representing the same region) to be similar, and two hidden vectors from different satellite images (i.e., representing different regions) to be dissimilar. As such, we can pre-train our Multi-Modal Transformer to capture the impact of short-term meteorological parameters on crop growth without labor-intensive human supervision. + +Spatial Transformer. Recall that the Sentinel-2 Imagery dataset of a county is partitioned into multiple fine-grained grids for precise agricultural tracking. To learn spatial dependency among those grids, we propose a Spatial Transformer $g_{\phi} : \mathbb{R}^{T \times G \times d} \to \mathbb{R}^{T \times d}$ , whose purpose is to capture the global spatial representations for counties. The design of our Spatial Transformer is inspired by the vanilla ViT [12] but with a flexible number of positional embeddings. It is used to tackle the scenario that the number of grids varies among counties as it depends on county sizes. To learn global spatial information for counties, the Spatial Transformer prepends a learnable classification token $v_{m}^{\mathrm{cls}} \in \mathbb{R}^{T \times 1 \times d}$ , arriving at + +$$ +\varphi_ {s} \left(\boldsymbol {v} _ {m}\right) = \left[ \boldsymbol {v} _ {m} ^ {\text {c l s}}; \boldsymbol {v} _ {m} ^ {1}; \boldsymbol {v} _ {m} ^ {2}; \dots ; \boldsymbol {v} _ {m} ^ {G} \right] + \mathbf {E} _ {\text {p o s}}, \tag {3} +$$ + +where $\mathbf{E}_{\mathrm{pos}} \in \mathbb{R}^{T \times (G + 1) \times d}$ is the flexible positional embeddings. We propose a Spatial Multi-Head Attention (S-MHA) to learn spatial dependency among grids. Mathematically, + +$$ +\operatorname {S - M H A} (\boldsymbol {Q}, \boldsymbol {K}, \boldsymbol {V}) = \operatorname {S o f t m a x} (\boldsymbol {Q} \boldsymbol {K} ^ {T} / \sqrt {d}) \boldsymbol {V}, +$$ + +$$ +\boldsymbol {Q} = \boldsymbol {W} _ {s} ^ {Q} \cdot \varphi_ {s} (\boldsymbol {v} _ {m}), \boldsymbol {K} = \boldsymbol {W} _ {s} ^ {K} \cdot \varphi_ {s} (\boldsymbol {v} _ {m}), \tag {4} +$$ + +$$ +\boldsymbol {V} = \boldsymbol {W} _ {s} ^ {V} \cdot \varphi_ {s} (\boldsymbol {v} _ {m}). +$$ + +Here, $\boldsymbol{W}_s^Q, \boldsymbol{W}_s^K, \boldsymbol{W}_s^V$ are three learnable matrices, similar to those given in Eq. (1). Finally, we regard the head of output sequences as global spatial representations of counties. That is, we have $g_{\phi}(\boldsymbol{v}_m) = \boldsymbol{v}_s$ , with $\boldsymbol{v}_s \in \mathbb{R}^{T \times d}$ signifying the hidden vector that incorporates global spatial information. + +Temporal Transformer. The Temporal Transformer possesses two goals. The first goal aims to learn temporal dependency among the hidden vectors $\boldsymbol{v}_s$ , i.e., the outputs of our Spatial Transformer. The second goal is to capture the effect of long-term climate change on crop yields. To achieve the first goal, we add a classification token $\boldsymbol{v}_s^{\mathrm{cls}}$ for learning the global temporal representation, i.e., + +$$ +\varphi_ {t} \left(\boldsymbol {v} _ {s}\right) = \left[ \boldsymbol {v} _ {s} ^ {\text {c l s}}; \boldsymbol {v} _ {s} ^ {1}; \boldsymbol {v} _ {s} ^ {2}; \dots ; \boldsymbol {v} _ {s} ^ {T} \right] + \mathbf {E} _ {\text {t m p}}, \tag {5} +$$ + +where $\mathbf{E}_{\mathrm{tmp}} \in \mathbb{R}^{(T + 1) \times d}$ is the temporal embedding, similar to the positional embeddings $\mathbf{E}_{\mathrm{pos}}$ expressed in Eq. (3). The novel Temporal Multi-Head Attention (T-MHA) is also devised to capture the impact of long-term historical meteorological parameters on crop yields. Its key idea is to incorporate a relative meteorological bias into each head for similarity computation, motivated by prior studies [6, 38, 33]. + +Mathematically, our T-MHA can be expressed by + +$$ +\begin{array}{l} \operatorname {T} - \operatorname {M H A} (\boldsymbol {Q}, \boldsymbol {K}, \boldsymbol {V}) = \operatorname {S o f t m a x} (\boldsymbol {Q} \boldsymbol {K} ^ {\boldsymbol {T}} / \sqrt {d} + \pi_ {t} (\boldsymbol {y} _ {l})) \boldsymbol {V}, \\ \boldsymbol {Q} = \boldsymbol {W} _ {t} ^ {Q} \cdot \varphi_ {t} (\boldsymbol {v} _ {s}), \boldsymbol {K} = \boldsymbol {W} _ {t} ^ {K} \cdot \varphi_ {t} (\boldsymbol {v} _ {s}), \\ \boldsymbol {V} = \boldsymbol {W} _ {t} ^ {V} \cdot \varphi_ {t} (\boldsymbol {v} _ {s}). \tag {6} \\ \end{array} +$$ + +Here, $\pmb{y}_l$ represents the long-term meteorological parameters, and $\pi_t(\cdot)$ is a linear projection layer. Similarly, $\pmb{W}_t^Q$ , $\pmb{W}_t^K$ , $\pmb{W}_t^V$ are three learnable matrices. In summary, our Temporal Transformer $h_\psi : (\mathbb{R}^{T \times d}, \mathbb{R}^{T \times N_2 \times d_y}) \to \mathbb{R}^d$ can be defined as $h_\psi(\pmb{v}_s, \pmb{y}_l) = \pmb{v}_t$ , with $\pmb{v}_t \in \mathbb{R}^d$ being the hidden vector that incorporates both global temporal information and the impact of climate change on crops simultaneously. + +Finally, the hidden vector $\pmb{v}_t$ is fed into a linear classifier for crop yield predictions, i.e., $\hat{\pmb{z}} = \pmb{W}^T\pmb{v}_t + \pmb{b}$ , with $\pmb{W}$ and $\pmb{b}$ respectively denoting the weights and the bias for the classifier, and $\hat{\pmb{z}} \in \mathbb{R}^{d_z}$ indicating the crop yield prediction. + +# 5. Experiments + +We conduct experiments for the county-level crop yield predictions across four U.S. states, i.e., Mississippi (MS), Louisiana (LA), Iowa (IA), and Illinois (IL). Four types of crops, i.e., corn, cotton, soybean, and winter wheat, are taken into account for performance evaluation. + +# 5.1. Experimental Settings + +Datasets. We utilize the Sentinel-2 imagery and the daily HRRR data datasets during the growing season respectively as the remote sensing data and the short-term meteorological data. Meanwhile, the monthly HRRR data from the previous three years are used as the long-term meteorological parameters. + +Compared Approaches. We compare our proposed MMST-ViT to three DL-based approaches, with one, i.e., ConvLSTM [43], developed for spatial-temporal prediction, and the other two, i.e., CNN-RNN [28] and GNN-RNN [15], developed for crop yield predictions. Minor rectifications are made to them so that they can admit the Sentinel-2 imagery and HRRR datasets as their inputs. Other hyperparameters, unless specified otherwise, are set to the values as those reported in their original studies. + +Metrics. We take three performance metrics, i.e., Root Mean Square Error (RMSE), R-squared $(\mathbf{R}^2)$ , and Pearson Correlation Coefficient (Corr), for comparative evaluation. Notably, a lower value of RMSE or a higher value of $\mathbf{R}^2$ (or Corr) indicates better performance. + +Model Size. Our proposed MMST-ViT builds on the top of Vision Transformer (ViT) [12]. Similar to ViT, it consists of a stack of Transformer blocks [50], where each Transformer block includes a Multi-Head Attention (MHA) block and + +Table 2: Model details used in our study + +
ModelLayerHidden SizeHeadMLP SizeOthers
Multi-Modal TransformerPVT-T/4{2, 2, 2, 2}{64, 128, 320, 512}{1, 2, 5, 8}{512, 1024, 1280, 2048}SR Ratios = {8, 4, 2, 1}
MM-MHA251282048Context Size = 9
Spatial TransformerS-MHA451232048-
Temporal TransformerT-MHA451232048Context Size = 9
+ +Table 3: Overall comparative crop yield predictions for 2021, with the best results shown in bold. Cotton yields are measured in pounds per acre (LB/AC), whereas other crop yields are measured in bushels per acre (BU/AC) + +
MethodCornCottonSoybeanWinter Wheat
RMSE (↓)R2(↑)Corr (↑)RMSE (↓)R2(↑)Corr (↑)RMSE (↓)R2(↑)Corr (↑)RMSE (↓)R2(↑)Corr (↑)
ConvLSTM18.60.6110.78265.40.7150.8467.20.6160.7857.40.5110.715
CNN-RNN14.60.7050.83969.50.6530.8085.80.7030.8397.50.6140.783
GNN-RNN14.20.7300.85458.50.6470.8045.40.7480.8656.00.6210.788
Ours10.50.8110.90042.40.7900.8893.90.8430.9184.60.7850.886
+ +an MLP block, and both of which incorporate the LayerNorm [4] for normalization. Table 2 presents the details of model sizes used in our experiments. Note that "PVT-T/4" refers to the PVT-Tiny model with a patch size of 4, and "SR Ratios" represents the spatial reduction ratio in PVT. Following the original PVT [51], we divide the PVT backbone into four stages and report the corresponding model sizes at each stage in the second row of Table 2. The other transformers are single-stage, similar to the vanilla ViT [12]. Notably, "Context Size" represents the number of meteorological parameters used in our study. + +Hyperparameters. Our model is pre-trained for 200 epochs using AdamW [35] with $\beta_{1} = 0.9$ , $\beta_{2} = 0.95$ , a weight decay of 0.05, and a cosine decay schedule [34] with an initial learning rate of $1e - 4$ , and warmup epochs of 20. To perform data augmentation for pre-training, various techniques such as random cropping, random horizontal flipping, random Gaussian blur, and color jittering are employed. These techniques are similar to those used in SimCLR [9]. After pre-training, we fine-tune our proposed MMST-ViT for 100 epochs using AdamW with $\beta_{1} = 0.9$ , $\beta_{2} = 0.999$ , a cosine decay schedule with an initial learning rate of $1e - 3$ , and warmup epochs of 5. + +# 5.2. Comparative Performance Evaluation + +We conduct experiments for predicting 2021 crop yields at the county level across four aforementioned U.S. states, with prediction performance measured by the three metrics of RMSE, $\mathbf{R}^2$ , and Corr. + +Table 3 lists the comparative performance results of our MMST-ViT and its three counterparts, i.e., ConvLSTM, CNN-RNN, and GNN-RNN. Four observations are obtained from the table. First, our approach achieves the best performance under all metrics. In particular, for the soybean yield prediction, our approach achieves the lowest RMSE of 3.9 and the highest $R^2$ (or Corr) of 0.843 (or 0.918). With the lowest RMSE value, our predicted soybean + +yields are the closest to the actual amounts. In addition, the highest $\mathbb{R}^2$ and Corr values demonstrate that our predicted soybean yields are best correlated to actual figures. Second, our approach significantly outperforms ConvLSTM, with its RMSE values always lower than those of ConvLSTM markedly, ranging from 2.8 (for winter wheat) to 23.0 (for cotton). The reason is that ConvLSTM overlooks the impact of meteorological parameters on crop growth. Third, CNN-RNN underperforms our approach by 4.1 (for corn), by 27.1 (for cotton), by 1.9 (for soybean), and by 2.9 (for winter wheat), in terms of RMSE, though both models take into account the effect of long-term climate change on crop yields. Because CNN-RNN cannot model the spatial dependency among neighborhood regions. Fourth, MMST-ViT outperforms the most recent state-of-the-art (i.e., GNN-RNN) measurably. Specifically, our RMSE value is lower by 16.1 for cotton, whereas our $\mathbb{R}^2$ and Corr values are better respectively by 0.165 and 0.098 for winter wheat. These results are contributed by leveraging both visual remote sensing and numerical meteorological data in our model, while GNN-RNN only considers the meteorological data. + +# 5.3. Visualizing Crop Yield Prediction Errors + +In this section, we conduct experiments to visualize crop yield prediction errors across four U.S. states: Mississippi (MS), Louisiana (LA), Iowa (IA), and Illinois (IL). We use the same experimental settings as those stated in Section 5.2. Figure 4 shows the absolute prediction errors for soybean across counties/parishes in the four states, with navy blue and light blue respectively indicating the high and low absolute errors. Our MMST-ViT model is highly effective in predicting crop yields, with the absolute prediction errors of $57.2\%$ counties below 3 BU/AC. Furthermore, we discover that $95.1\%$ of counties in MS, $92.5\%$ of parishes in LA, $86.8\%$ of counties in IA, and $91.0\%$ of counties in IL achieve decent absolute prediction errors (i.e., $\leq 6$ BU/AC). These empirical findings validate the robustness of MMST- + +![](images/1d956d0f443ff02eb3c3de0c0df4b4f9e29d5c5b3ef47f1fc674f60ffed88d87.jpg) +(a) Mississippi (MS) + +![](images/a20a4814dbeb98971c8420c01c0b1476f491d2a264d5b104b5965ccda583e431.jpg) +(b) Louisiana (LA) +Figure 4: Illustration of absolute prediction errors for soybean across four U.S. states. Note that a county/parish with $< 0$ indicates its soybean yield data is unavailable. + +![](images/9f48bfe618aec09d00e9ca2aa12c65b24bc4068d39246a24a9a52780825238bd.jpg) +(c) Iowa (IA) + +![](images/3471bae2b18dc576cc4955b1861ea12ba673c9f35f7db00c4b7c95bfd467e959.jpg) +(d) Illinois (IL) + +ViT across various geographic locations. + +# 5.4. Performance of One Year Ahead Predictions + +In practice, predicting crop yields well in advance of harvest, can provide valuable information for farmers, agribusinesses, and governments in their agricultural planning and decision-making processes. This information can be used to elevate agricultural resilience and sustainability, make informed financial decisions, and support global food security [23]. A prior study [15] simulated the early prediction scenario by masking partial inputs, successfully making predictions several months before harvest. In this study, we attempt a step further by making crop yield predictions one year before the harvest. In particular, we leverage remote sensing and short-term meteorological data during the growing season in the current year to predict crop yields in the next year. For example, the Sentinel-2 imagery and daily HRRR data during the growing season in 2020 are utilized as remote sensing data and the short-term meteorological data for predicting crop yields in 2021. + +Figure 5 illustrates the experimental results. It is observed that our MMST-ViT outperforms three baseline models, i.e., ConvLSTM, CNN-RNN, and GNN-RNN, for the predictions of one year ahead. Among all crops, MMST-ViT achieves the lowest RMSE values ranging from 4.7 (for soybean) to 50.2 (for cotton), the highest $\mathbb{R}^2$ values ranging from 0.711 (for winter wheat) to 0.792 (for soybean), and the highest Corr values ranging from 0.843 (for winter wheat) to 0.890 (for soybean). Additionally, compared to its in-season prediction results (see the 6th row of Table 3), the one year ahead prediction outcomes of our approach are just slightly inferior, degraded respectively by $8.6\%$ , of $15.5\%$ , of $17.0\%$ , and of $14.6\%$ in terms of RMSE for corn, cotton, soybean, and winter wheat. The empirical results confirm the robustness of MMST-ViT. + +Interestingly, we also observe that the prediction results for the cotton have a high RMSE value but not a low $\mathbb{R}^2$ (or Corr) value. This is because the cotton yield is measured by pounds per acre (LB/AC), with a high standard deviation value of 250.1, while other crop yields are measured by bushels per acre (BU/AC), with low standard deviation val + +Table 4: Ablation studies for different components, with five scenarios considered and the last row listing the results of MMST-ViT + +
ComponentCornSoybean
RMSE (↓)Corr (↑)RMSE (↓)Corr (↑)
Temporal Transformerw/o long-term14.50.8436.20.850
w/o T-MHA15.70.8205.60.839
Spatial Transformerw/o S-MHA13.50.8565.60.849
Multi-Modal Transformerw/o short-term13.60.8396.10.845
w/o image15.20.8096.80.822
MMST-ViT-10.50.9003.90.918
+ +ues (e.g., 11.8 for soybean). In scenarios with high variance data, the RMSE value may worsen due to larger residuals, while the $\mathbf{R}^2$ value improves due to the increased proportion of explained variance. + +# 5.5. Ablation Studies + +Key Components. We next conduct experiments to show how each key component in our MMST-ViT affects prediction performance. Table 4 lists the results of our ablation studies under five different scenarios, with one shown in a row. Here, "w/o long-term" indicates masking the long-term meteorological data, and "w/o T-MHA" represents the absence of our Temporal Transformer and instead resorting to the average pooling to obtain the global temporal representation. Similarly, "w/o S-MHA" denotes utilizing the average pooling to obtain the global spatial representation. The scenarios of "w/o short-term" and "w/o image" represent respectively masking the short-term meteorological data and the remote sensing data from the Multi-Modal Transformer. Note that masking either data makes our model unable to conduct MM-MHA, following Eq. (1). The results of our complete MMST-ViT outcomes are shown in the last row of Table 4. + +Three observations can be made from Table 4. First, the long-term meteorological data degrades the Corr value by 0.057 (or 0.068) for corn (or soybean). This validates that crop yield prediction accuracy can benefit from histori + +![](images/5abb09dbcdc3fcf16fb337d1991bb01de120a1221fa2d52f42cf2d9c51aacbfe.jpg) +(a) RMSE + +![](images/301bb5ac0757881f7c7e642ca0cefbee658c57c8b9bc4ef9cd5d4f8be09de8f1.jpg) +(b) $\mathbf{R}^2$ +Figure 5: Illustration of the performance for predictions of one year ahead under (a) RMSE, (b) $\mathbb{R}^2$ , and (c) Corr, with the cotton yield measured by LB/AC and other crop yields measured by BU/AC. + +![](images/2c95e90e2b35bedf7a8f2b2f39fc5e00c6a9db14f757b8797ea9ee5e12ac9fe2.jpg) +(c) Corr + +ical meteorological data, which dictates long-term climate change. Second, the absence of either the Temporal Transformer or the Spatial Transformer lowers the Corr value by 0.080 (for corn) and by 0.069 (for soybean), respectively. Third, unable to conduct MM-MHA as the result of masking the short-term meteorological data or the satellite images degrades prediction performance greatly. For example, masking the short-term meteorological data (or satellite images) causes the Corr value degradation by 0.096 (or 0.073) for soybean. This statistical evidence exhibits the importance of our Multi-Modal Transformer for capturing the impact of meteorological parameters on crop growth. + +Pre-training Techniques. We conduct experiments to explore the impact of our proposed multi-modal self-supervised pre-training, i.e., Eq. (2), on the crop yield prediction. We consider three scenarios, i.e., MMST-ViT without pre-training, with the pre-training technique described in SimCLR [9], and with our multi-modal pre-training. Table 5 presents the prediction performance outcomes. The table reveals that our MMST-ViT (w/ our multi-modal pretraining) significantly outperforms its counterpart (w/o pretraining), exhibiting a lower RMSE value by 2.7 (or 1.2) and a larger Corr value by 0.043 (or 0.043) for corn (or soybean), due to two reasons. First, Vision Transformer (ViT)-based models are prone to overfitting [12], but our multi-modal self-supervised learning can significantly mitigate this issue by leveraging both visual remote sensing data and numerical meteorological data for pre-training. Second, our multi-modal self-supervised pre-training may can capture the impact of meteorological parameters on the crops. In contrast, pre-training our MMST-ViT with the SimCLR technique only achieves marginal performance improvement (compared to the one w/o pre-training), achieving the Corr improvement of 0.001 (0.875 v.s. 0.876) for soybean. This is because the SimCLR technique fails to leverage numerical meteorological parameters for pre-training. These empirical results validate the necessity and importance of our proposed multi-modal pre-training for accurate crop yield predictions. + +Table 5: Ablation studies for different pre-training techniques, with three scenarios considered + +
MethodCornSoybean
RMSE (↓)Corr (↑)RMSE (↓)Corr (↑)
w/o pretraining13.20.8575.10.875
w/ SimCLR12.90.8574.90.876
w/ multi-modal pretraining10.50.9003.90.918
+ +# 6. Conclusion + +This paper has proposed the Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), a climate change-aware deep learning approach for predicting crop yields at the county level across the United States. MMST-ViT comprises three key components of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer. Three innovative Multi-Head Attention (MHA) mechanisms are introduced, one for each component. As a result, our MMST-ViT can leverage both the visual remote sensing data and the numerical meteorological data for capturing the impact of short-term growing season weather variations and long-term climate change on crop yields. Additionally, a novel multi-modal contrastive learning technique has been developed, able to effectively pre-train our model without the need of human supervision. We have conducted extensive experiments on $200+$ counties/parishes located in 4 U.S. states, with the results demonstrating that our proposed MMST-ViT substantially outperforms its state-of-the-art counterparts consistently under three performance metrics of interest. + +# Acknowledgments + +This work was supported in part by NSF under Grants 2019511, 2146447, and in part by the BoRSF under Grants LEQSF(2019-22)-RD-A-21 and LEQSF(2021-22)-RD-D-07. Any opinion and findings expressed in the paper are those of the authors and do not necessarily reflect the view of funding agencies. + +# References + +[1] Faezeh Akhavizadegan, Javad Ansarifar, Lizhi Wang, Isaiah Huber, and Sotirios V Archontoulis. A time-dependent parameter estimation framework for crop modeling. Scientific reports, 2021. +[2] Javad Ansarifar, Lizhi Wang, and Sotirios V Archontoulis. An interaction regression model for crop yield prediction. Scientific reports, 2021. +[3] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In International Conference on Computer Vision (ICCV), 2021. +[4] Jimmy Lei Ba, Jamie Ryan Kiros, and Geoffrey E Hinton. Layer normalization. arXiv preprint arXiv:1607.06450, 2016. +[5] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. Beit: BERT pre-training of image transformers. In International Conference on Learning Representations (ICLR), 2022. +[6] Hangbo Bao, Li Dong, Furu Wei, Wenhui Wang, Nan Yang, Xiaodong Liu, Yu Wang, Jianfeng Gao, Songhao Piao, Ming Zhou, and Hsiao-Wuen Hon. Unilmv2: Pseudo-masked language models for unified language model pre-training. In International Conference on Machine Learning (ICML), 2020. +[7] Mathilde Caron, Hugo Touvron, Ishan Misra, Hervé Jégou, Julien Mairal, Piotr Bojanowski, and Armand Joulin. Emerging properties in self-supervised vision transformers. In International Conference on Computer Vision (ICCV), 2021. +[8] Liyan Chen, Weihan Wang, and Philippos Mordohai. Learning the distribution of errors in stereo matching for joint disparity and uncertainty estimation. In Computer Vision and Pattern Recognition (CVPR), 2023. +[9] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey E. Hinton. A simple framework for contrastive learning of visual representations. In International Conference on Machine Learning (ICML), 2020. +[10] Minghan Cheng, Xiyun Jiao, Lei Shi, Josep Penuelas, Lalit Kumar, Chenwei Nie, Tianao Wu, Kaihua Liu, Wenbin Wu, and Xiuliang Jin. High-resolution crop yield and water productivity dataset generated using random forest and remote sensing. Scientific Data, 2022. +[11] Karine Chenu, John Roy Porter, Pierre Martre, Bruno Basso, Scott Cameron Chapman, Frank Ewert, Marco Bindi, and Senthold Asseng. Contribution of crop models to adaptation in wheat. Trends in plant science, 2017. +[12] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations (ICLR), 2021. +[13] Nicola Falco, Haruko M Wainwright, Baptiste Dafflon, Craig Ulrich, Florian Soom, John E Peterson, James Bentley Brown, Karl B Schaettle, Malcolm Williamson, Jackson D Cothren, et al. Influence of soil heterogeneity on soybean plant development and crop yield evaluated using time-series + +of uav and ground-based geophysical imagery. Scientific reports, 2021. +[14] Haoqi Fan, Bo Xiong, Karttikeya Mangalam, Yanghao Li, Zhicheng Yan, Jitendra Malik, and Christoph Feichtenhofer. Multiscale vision transformers. In International Conference on Computer Vision (ICCV), 2021. +[15] Joshua Fan, Junwen Bai, Zhiyun Li, Ariel Ortiz-Bobea, and Carla P. Gomes. A GNN-RNN approach for harnessing geospatial and temporal information: Application to crop yield prediction. In AAAI, 2022. +[16] Niketa Gandhi, Owaiz Petkar, and Leisa J Armstrong. Rice crop yield prediction using artificial neural networks. In 2016 IEEE Technological Innovations in ICT for Agriculture and Rural Development (TIAR), 2016. +[17] Vivien Sainte Fare Garnot and Loic Landrieu. Panoptic segmentation of satellite image time series with convolutional temporal attention networks. In International Conference on Computer Vision (ICCV), 2021. +[18] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross B. Girshick. Masked autoencoders are scalable vision learners. In Conference on Computer Vision and Pattern Recognition (CVPR), 2022. +[19] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Conference on Computer Vision and Pattern Recognition (CVPR), 2016. +[20] Yi He, Fudong Lin, Xu Yuan, and Nian-Feng Tzeng. Interpretable minority synthesis for imbalanced classification. In IJCAI, 2021. +[21] Byeongho Heo, Sangdoo Yun, Dongyoon Han, Sanghyuk Chun, Junsuk Choe, and Seong Joon Oh. Rethinking spatial dimensions of vision transformers. In International Conference on Computer Vision (ICCV), 2021. +[22] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 1997. +[23] Takeshi Horie, Masaharu Yajima, and Hiroshi Nakagawa. Yield forecasting. Agricultural systems, 1992. +[24] HRRR. The high-resolution rapid refresh (hrrr), 2022. +[25] James W Jones, John M Antle, Bruno Basso, Kenneth J Boote, Richard T Conant, Ian Foster, H Charles J Godfray, Mario Herrero, Richard E Howitt, Sander Janssen, et al. Toward a new generation of agricultural system data, models, and knowledge products: State of agricultural systems science. Agricultural systems, 2017. +[26] Saeed Khaki, Hieu Pham, and Lizhi Wang. Simultaneous corn and soybean yield prediction from remote sensing data using deep transfer learning. Scientific Reports, 2021. +[27] Saeed Khaki and Lizhi Wang. Crop yield prediction using deep neural networks. Frontiers in plant science, 2019. +[28] Saeed Khaki, Lizhi Wang, and Sotirios V Archontoulis. A cnn-rnn framework for crop yield prediction. Frontiers in Plant Science, 2020. +[29] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E. Hinton. Imagenet classification with deep convolutional neural networks. In Neural Information Processing Systems (NeurIPS), 2012. +[30] Zhengfeng Lai, Sol Vesdapunt, Ning Zhou, Jun Wu, Cong Phuoc Huynh, Xuelu Li, Kah Kuen Fu, and Chen-Nee + +Chuah. Padclip: Pseudo-labeling with adaptive debiasing in clip for unsupervised domain adaptation. In International Conference on Computer Vision (ICCV), 2023. +[31] Yanghao Li, Chao-Yuan Wu, Haoqi Fan, Karttikeya Mangalam, Bo Xiong, Jitendra Malik, and Christoph Feichtenhofer. Mvitv2: Improved multiscale vision transformers for classification and detection. In Computer Vision and Pattern Recognition (CVPR), 2022. +[32] Fudong Lin, Xu Yuan, Lu Peng, and Nian-Feng Tzeng. Cascade variational auto-encoder for hierarchical disentangle-. ment. In Conference on Information & Knowledge Management (CIKM), 2022. +[33] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In International Conference on Computer Vision (ICCV), 2021. +[34] Ilya Loshchilov and Frank Hutter. SGDR: stochastic gradient descent with warm restarts. In International Conference on Learning Representations (ICLR), 2017. +[35] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In International Conference on Learning Representations, 2019. +[36] Spyridon Mourtzinis, Paul D Esker, James E Specht, and Shawn P Conley. Advancing agricultural research using machine learning algorithms. Scientific reports, 2021. +[37] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, Gretchen Krueger, and Ilya Sutskever. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning (ICML), 2021. +[38] Colin Raffel, Noam Shazeer, Adam Roberts, Katherine Lee, Sharan Narang, Michael Matena, Yanqi Zhou, Wei Li, and Peter J Liu. Exploring the limits of transfer learning with a unified text-to-text transformer. The Journal of Machine Learning Research, 2020. +[39] David Rolnick, Priya L Donti, Lynn H Kaack, Kelly Kochanski, Alexandre Lacoste, Kris Sankaran, Andrew Slavin Ross, Nikola Milojevic-Dupont, Natasha Jaques, Anna Waldman-Brown, et al. Tackling climate change with machine learning. ACM Computing Surveys (CSUR), 2022. +[40] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Conference on Computer Vision and Pattern Recognition (CVPR), 2022. +[41] Sentinel-Hub. Sentinel hub process api, 2022. +[42] Mohsen Shahhosseini, Guiping Hu, Isaiah Huber, and Sotirios V Archontoulis. Coupling machine learning and crop modeling improves crop yield prediction in the us corn belt. Scientific reports, 2021. +[43] Xingjian Shi, Zhourong Chen, Hao Wang, Dit-Yan Yeung, Wai-Kin Wong, and Wang-chun Woo. Convolutional LSTM network: A machine learning approach for precipitation nowcasting. In Neural Information Processing Systems (NeurIPS), 2015. +[44] Fulu Tao, Masayuki Yokozawa, and Zhao Zhang. Modelling the impacts of weather and climate variability on crop pro + +ductivity over a large area: a new process-based model development, optimization, and uncertainties analysis. agricultural and forest meteorology, 2009. +[45] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. VideoMAE: Masked autoencoders are data-efficient learners for self-supervised video pre-training. In Neural Information Processing Systems (NeurIPS), 2022. +[46] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Hervé Jégou. Training data-efficient image transformers & distillation through attention. In Marina Meila and Tong Zhang, editors, International Conference on Machine Learning (ICML), 2021. +[47] Gabriel Tseng, Ivan Zvonkov, Catherine Nakalembe, and Hannah Kerner. Cropharvest: a global satellite dataset for crop type classification. Neural Information Processing Systems (NeurIPS), 2021. +[48] Matteo Turchetta, Luca Corinzia, Scott Sussex, Amanda Burton, Juan Herrera, Ioannis N Athanasiadis, Joachim M Buhmann, and Andreas Krause. Learning long-term crop management strategies with cyclesgym. In Neural Information Processing Systems (NeurIPS), 2022. +[49] USDA. The united states department of agriculture (usda), 2022. +[50] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Neural Information Processing Systems (NeurIPS), 2017. +[51] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In International Conference on Computer Vision (ICCV), pages 548-558, 2021. +[52] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. PVT v2: Improved baselines with pyramid vision transformer. Comput. Vis. Media, 2022. +[53] Xiaocui Wu, Xiangming Xiao, Jean Steiner, Zhengwei Yang, Yuanwei Qin, and Jie Wang. Spatiotemporal changes of winter wheat planted and harvested areas, photosynthesis and grain production in the contiguous united states from 2008-2018. Remote Sensing, 2021. +[54] Rongting Xu, Hanqin Tian, Shufen Pan, Stephen A Prior, Yucheng Feng, William D Batchelor, Jian Chen, and Jia Yang. Global ammonia emissions from synthetic nitrogen fertilizer applications in agricultural systems: Empirical and process-based estimates and uncertainty. *Global change biology*, 2019. +[55] Li Yuan, Yunpeng Chen, Tao Wang, Weihao Yu, Yujun Shi, Zihang Jiang, Francis E. H. Tay, Jiashi Feng, and Shuicheng Yan. Tokens-to-token vit: Training vision transformers from scratch onImagenet. In International Conference on Computer Vision (ICCV), 2021. +[56] Yihe Zhang, Xu Yuan, Sytske K. Kimball, Eric Rappin, Li Chen, Paul J. Darby III, Tom Johnsten, Lu Peng, Boisy Pitre, David Bourrie, and Nian-Feng Tzeng. Precise weather parameter predictions for target regions via neural networks. In ECML-PKDD. Applied Data Science Track, 2021. \ No newline at end of file diff --git a/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/images.zip b/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..3fc24035a01e1c7e182627e3b552592f8272ec6b --- /dev/null +++ b/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:0261cefd34eb74769d82877b141b872481c11db69ce40ae482d29b8517feb36e +size 395405 diff --git a/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/layout.json b/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..2cdeaf5d387a4c45027f5d10d015606c4dbe520a --- /dev/null +++ b/2023/MMST-ViT_ Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer/layout.json @@ -0,0 +1,9451 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 64, + 102, + 531, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 64, + 102, + 531, + 140 + ], + "spans": [ + { + "bbox": [ + 64, + 102, + 531, + 140 + ], + "type": "text", + "content": "MMST-ViT: Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "spans": [ + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": "Fudong Lin" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Summer Crawford" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Kaleb Guillot" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Yihe Zhang" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Yan Chen" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Xu Yuan" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Li Chen" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Shelby Williams" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Robert Minvielle" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Xiangming Xiao" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Drew Gholson" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{5}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Nicolas Ashwell" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{5}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Tri Setiyono" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{6}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Brenda Tubana" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{7}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Lu Peng" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{8}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Magdy Bayoumi" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": ", Nian-Feng Tzeng" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": " University of Delaware, " + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": " University of Louisiana at Lafayette, " + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": " University of Connecticut, " + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": " University of Oklahoma, " + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{5}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": " Mississippi State University, " + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{6}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": " Louisiana State University, " + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{7}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": " LSU AgCenter, " + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "inline_equation", + "content": "^{8}" + }, + { + "bbox": [ + 52, + 160, + 556, + 246 + ], + "type": "text", + "content": " Tulane University" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 273, + 192, + 285 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 273, + 192, + 285 + ], + "spans": [ + { + "bbox": [ + 143, + 273, + 192, + 285 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 298, + 290, + 681 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 298, + 290, + 681 + ], + "spans": [ + { + "bbox": [ + 46, + 298, + 290, + 681 + ], + "type": "text", + "content": "Precise crop yield prediction provides valuable information for agricultural planning and decision-making processes. However, timely predicting crop yields remains challenging as crop growth is sensitive to growing season weather variation and climate change. In this work, we develop a deep learning-based solution, namely Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), for predicting crop yields at the county level across the United States, by considering the effects of short-term meteorological variations during the growing season and the long-term climate change on crops. Specifically, our MMST-ViT consists of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer. The Multi-Modal Transformer leverages both visual remote sensing data and short-term meteorological data for modeling the effect of growing season weather variations on crop growth. The Spatial Transformer learns the high-resolution spatial dependency among counties for accurate agricultural tracking. The Temporal Transformer captures the long-range temporal dependency for learning the impact of long-term climate change on crops. Meanwhile, we also devise a novel multi-modal contrastive learning technique to pre-train our model without extensive human supervision. Hence, our MMST-ViT captures the impacts of both short-term weather variations and long-term climate change on crops by leveraging both satellite images and meteorological data. We have conducted extensive experiments on over 200 counties in the United States, with the experimental results exhibiting that our MMST-ViT outperforms its counterparts under three performance metrics of interest. Our dataset and code are available at https://github.com/fudong03/MMST-ViT." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 307, + 273, + 386, + 285 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 273, + 386, + 285 + ], + "spans": [ + { + "bbox": [ + 307, + 273, + 386, + 285 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 293, + 547, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 293, + 547, + 533 + ], + "spans": [ + { + "bbox": [ + 304, + 293, + 547, + 533 + ], + "type": "text", + "content": "Accurate crop yield prediction is essential for agricultural planning and advisory processes [26], informed economic decisions [2], and global food security [36]. However, predicting crop yields precisely is challenging as it requires to consider the effects of i) short-term weather variations, governed by the meteorological data during the growing season, and ii) long-term climate change, governed by historical meteorological factors, on crops simultaneously. Meanwhile, precise crop tracking relies on high-resolution remote sensing data. While process-based prediction approaches [44, 11, 25, 54] exist, they often suffer from high inaccuracies due to their strong assumptions on management practices [15]. On the other hand, motivated by the recent success of deep neural networks [29, 19, 50, 12, 20, 56, 37, 32, 18, 30, 8], deep learning (DL)-based methods have been widely adopted for crop yield predictions, due to their effectiveness in accurate agricultural tracking [27, 26] and their potent capabilities in capturing the spatial and temporal variation of meteorological data [28, 15]." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 533, + 547, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 547, + 689 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 547, + 689 + ], + "type": "text", + "content": "So far, DL-based solutions for crop yield predictions can be roughly grouped into two categories, i.e., remote sensing data-based and meteorological data-based approaches. The former [27, 26, 53, 13, 17, 47, 10] employs such remote sensing data as satellite images, unmanned aerial vehicle (UAV)-based imagery data, or vegetation indices to estimate the annual crop yield, while the latter [16, 1, 36, 42, 48] predicts the crop yield by using meteorological parameter data, including temperature, precipitation, vapor pressure deficit, etc. However, the former overlooks the direct impact of meteorological parameters on crop growth, while the latter lacks high-resolution remote sensing data for accurate agricultural tracking." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 689, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 547, + 715 + ], + "type": "text", + "content": "A recent study [39] has reported that the long-term climate change would gradually decrease the crop yield." + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 702, + 241, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 241, + 713 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 241, + 713 + ], + "type": "text", + "content": "*Corresponding author: Dr. Xu Yuan (xyuan@udel.edu)" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 295, + 748, + 316, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 316, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 316, + 758 + ], + "type": "text", + "content": "5774" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 49, + 72, + 286, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 72, + 286, + 251 + ], + "spans": [ + { + "bbox": [ + 49, + 72, + 286, + 251 + ], + "type": "text", + "content": "Driven by this discovery, follow-up pursuits have attempted to explore the effect of long-term climate change on crops. For example, the CNN-RNN model [28] demonstrates that the crop yield prediction can benefit from historical meteorological data, which is essential for measuring the impacts of climate change. Later, GNN-RNN [15] extends CNN-RNN by framing the crop yield prediction as the Spatial-Temporal forecasting problem. It employs Graph Neural Networks (GNN) and Long Short-Term Memory (LSTM) [22] respectively for learning spatial dependency among neighborhood counties and for capturing the impact of long-term meteorological data on crops. However, both of them only take into account the meteorological data for predictions, failing to leverage the remote sensing data for accurate agricultural tracking." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 258, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 258, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 49, + 258, + 286, + 712 + ], + "type": "text", + "content": "In this work, we aim to develop a new DL-based solution for predicting crop yields at the county level across the United States, by using both visual remote sensing data (from the Sentinel-2 satellite imagery [41]) and numerical meteorological data (from the HRRR model [24]). Our solution has two main goals. First, it captures the impacts of both short-term growing season weather variations and long-term climate change on crops. Second, it aims to leverage high-resolution remote sensing data for accurate agricultural tracking. To achieve our goals, we propose the Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), motivated by the recent success of Vision Transformers (ViT) [12]. To the best of our knowledge, MMST-ViT is the first ViT-based model for real-world crop yield prediction. It advances previous CNN/GNN-based and RNN-based counterparts respectively with better generalization to the multi-model data and with more powerful abilities in capturing long-term temporal dependency. Its three components of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer are each equipped with one novel Multi-Head Attention (MHA) mechanism [50]. Specifically, the Multi-Modal Transformer leverages satellite images and meteorological data during the growing season for capturing the direct impact of short-term weather variations on crop growth. The Spatial Transformer learns high-resolution spatial dependency among counties for precise crop tracking. The Temporal Transformer captures the effects of long-term climate change on crops. Since ViT-based models are prone to overfitting [12], we also develop a novel multi-modal contrastive learning technique that pre-trains our Multi-Modal Transformer without requiring human supervision. We have conducted experiments on over 200 counties in the United States. The experimental results exhibit that our MMST-ViT outperforms its state-of-the-art counterparts under three performance metrics of interest. For example, on the soybean prediction, our MMST-ViT achieves the lowest Root Mean Square Error (RMSE) value of 3.9, the highest R" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 308, + 73, + 544, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 73, + 544, + 95 + ], + "spans": [ + { + "bbox": [ + 308, + 73, + 544, + 95 + ], + "type": "text", + "content": "squared " + }, + { + "bbox": [ + 308, + 73, + 544, + 95 + ], + "type": "inline_equation", + "content": "(\\mathbb{R}^2)" + }, + { + "bbox": [ + 308, + 73, + 544, + 95 + ], + "type": "text", + "content": " value of 0.843, and the best Pearson Correlation Coefficient (Corr) value of 0.918." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 308, + 110, + 391, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 110, + 391, + 121 + ], + "spans": [ + { + "bbox": [ + 308, + 110, + 391, + 121 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 308, + 135, + 544, + 456 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 135, + 544, + 456 + ], + "spans": [ + { + "bbox": [ + 308, + 135, + 544, + 456 + ], + "type": "text", + "content": "Vision Transformers. Adopted from Transformers [50] in natural language processing, Vision Transformers (ViT) have exhibited commendable performance in various computer vision tasks. The original ViT [12] first partitions an image into a set of image patches, then applies Multi-Head Attention (MHA) [50] over the patches, and finally utilizes a learnable classification token to capture global visual representation for image classification. Several subsequent methods have been developed, including DeiT [46] for data-efficient ViT through knowledge distillation, Swin [33] for computation-efficient ViT using shifted windows, PVT [51] for dense prediction tasks, and MAE [18] for self-supervised learning, among others [7, 21, 14, 55, 3, 52, 31, 45]. However, applying prior ViT approaches to real-world crop yield prediction is challenging due to its needs of addressing the multi-modal inputs, of learning high-resolution spatial dependency, and of capturing long-range temporal dependency. Our work, based on ViT, advances existing methods by proposing three novel Multi-Head Attention (MHA) mechanisms respectively for leveraging both visual remote sensing data and numerical meteorological data, learning global spatial representation from multiple high-resolution data, and capturing the global temporal representation for measuring the long-term climate change effect. Additionally, we develop a new multi-modal contrastive learning technique to pre-train our multi-modal model for better prediction performance." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 308, + 463, + 544, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 463, + 544, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 463, + 544, + 712 + ], + "type": "text", + "content": "Deep Learning (DL) for Crop Yield Prediction. DL has been widely adopted for real-world crop yield predictions. Such prediction studies can be grouped into two categories: remote sensing data-based and meteorological data-based approaches. The former uses satellite images, unmanned aerial vehicle (UAV) data, or vegetation indices to estimate crop yields. Its prominent studies include the use of UAV-acquired RGB images [27] for predicting in-season crop yields, YieldNet [26] which resorts to transfer learning for simultaneously estimating the yields of multiple crop types, among many others [53, 13, 17, 47, 10]. By contrast, the latter utilizes deep neural networks (DNNs) to capture the impact of meteorological parameters on crop yields, including CNN-RNN [28] which incorporates long-term meteorological data, GNN-RNN [15] which extends CNN-RNN by using Graph Neural Networks (GNN) for learning spatial information, and others [16, 1, 36, 42, 48]. However, the remote sensing data-based solutions overlook the impact of meteorological parameters on crops, while the meteorological data-based solutions often fail to incorporate the remote sensing data, known to be crucial for accurate agricultural" + } + ] + } + ], + "index": 5 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 750, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 750, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 750, + 314, + 757 + ], + "type": "text", + "content": "5775" + } + ] + } + ], + "index": 6 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 47, + 101, + 288, + 158 + ], + "blocks": [ + { + "bbox": [ + 47, + 70, + 287, + 95 + ], + "lines": [ + { + "bbox": [ + 47, + 70, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 47, + 70, + 287, + 95 + ], + "type": "text", + "content": "Table 1: Overview of USDA Crop Dataset and HRRR Computed Dataset" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 47, + 101, + 288, + 158 + ], + "lines": [ + { + "bbox": [ + 47, + 101, + 288, + 158 + ], + "spans": [ + { + "bbox": [ + 47, + 101, + 288, + 158 + ], + "type": "table", + "html": "
DatasetParameters
USDAProduction, Yield
HRRRAveraged Temperature, Maximal Temperature, Minimal Temperature, Precipitation, Relative Humidity, Wind Gust, Wind Speed, Downward Shortwave Radiation Flux, Vapor Pressure Deficit
", + "image_path": "3a1ea68fc26358692057299737efb5d316530130db5e7737879d0cc18769bbf8.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 170, + 288, + 278 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 170, + 288, + 278 + ], + "spans": [ + { + "bbox": [ + 46, + 170, + 288, + 278 + ], + "type": "text", + "content": "tracking. Our work differs from prior studies in two aspects. First, it leverages both remote sensing data and meteorological data for capturing the impacts of both short-term growing season meteorological variations and the long-term climate change on crops. Second, it is the first to use Vision Transformers for crop yield predictions, advancing previous CNN/GNN- and RNN-based models respectively with better generalization to multi-modal data and with higher abilities for capturing long ranges of temporal dependency." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 290, + 105, + 303 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 290, + 105, + 303 + ], + "spans": [ + { + "bbox": [ + 47, + 290, + 105, + 303 + ], + "type": "text", + "content": "3. Datasets" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 310, + 287, + 381 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 310, + 287, + 381 + ], + "spans": [ + { + "bbox": [ + 46, + 310, + 287, + 381 + ], + "type": "text", + "content": "In this study, we utilize three types of data for accurate county-level crop yield predictions: i) crop data from the United States Department of Agriculture (USDA), ii) meteorological data from the High-Resolution Rapid Refresh (HRRR), and iii) remote sensing data from the Sentinel-2 satellite, as outlined below." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 385, + 287, + 470 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 385, + 287, + 470 + ], + "spans": [ + { + "bbox": [ + 46, + 385, + 287, + 470 + ], + "type": "text", + "content": "USDA Crop Dataset. The dataset, sourced from the United States Department of Agriculture (USDA) [49], provides annual crop data for major crops grown in the United States (U.S.), including corn, cotton, soybean, winter wheat, etc., on a county-level basis. It covers crop information such as production and yield from 2017 to 2022 (as listed in the second row of Table 1)." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 473, + 287, + 545 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 473, + 287, + 545 + ], + "spans": [ + { + "bbox": [ + 46, + 473, + 287, + 545 + ], + "type": "text", + "content": "HRRR Computed Dataset. The dataset, obtained from the High-Resolution Rapid Refresh atmospheric model (HRRR) [24], provides high-resolution meteorological data for the contiguous U.S. continent. It covers 9 weather parameters from 2017 to 2022 (see the third row in Table 1 for more information)." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 548, + 288, + 645 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 548, + 288, + 645 + ], + "spans": [ + { + "bbox": [ + 46, + 548, + 288, + 645 + ], + "type": "text", + "content": "Sentinel-2 Imagery. Sentinel-2 imagery is a set of images captured by the Sentinel-2 Earth observation satellite. It provides agriculture imagery for the contiguous U.S. continent from 2017 to 2022 with a 2-week interval. Since precise agricultural tracking requires high-resolution remote sensing data, the image of a county is partitioned into multiple fine-grained grids " + }, + { + "bbox": [ + 46, + 548, + 288, + 645 + ], + "type": "inline_equation", + "content": "(9 \\times 9 \\mathrm{~km})" + }, + { + "bbox": [ + 46, + 548, + 288, + 645 + ], + "type": "text", + "content": ". Figure 1 shows an example of county partitioning." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 657, + 102, + 669 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 657, + 102, + 669 + ], + "spans": [ + { + "bbox": [ + 47, + 657, + 102, + 669 + ], + "type": "text", + "content": "4. Method" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "type": "text", + "content": "In this work, we aim to develop a deep learning (DL)-based model for predicting crop yields at the county level. Our goals are twofold. First, we plan to capture the mete" + } + ] + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 313, + 73, + 425, + 213 + ], + "blocks": [ + { + "bbox": [ + 313, + 73, + 425, + 213 + ], + "lines": [ + { + "bbox": [ + 313, + 73, + 425, + 213 + ], + "spans": [ + { + "bbox": [ + 313, + 73, + 425, + 213 + ], + "type": "image", + "image_path": "a54ab7a758f291608607098d9237ba1146b2a18e99e9153ebcb5addbdf5ba50d.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 334, + 222, + 400, + 234 + ], + "lines": [ + { + "bbox": [ + 334, + 222, + 400, + 234 + ], + "spans": [ + { + "bbox": [ + 334, + 222, + 400, + 234 + ], + "type": "text", + "content": "(a) Grid Example" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 430, + 74, + 537, + 216 + ], + "blocks": [ + { + "bbox": [ + 430, + 74, + 537, + 216 + ], + "lines": [ + { + "bbox": [ + 430, + 74, + 537, + 216 + ], + "spans": [ + { + "bbox": [ + 430, + 74, + 537, + 216 + ], + "type": "image", + "image_path": "dce3b4c54d71d6cf4be6283f648381fab365ad2cdc8561a66846f80a56ecd2b4.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 443, + 223, + 525, + 234 + ], + "lines": [ + { + "bbox": [ + 443, + 223, + 525, + 234 + ], + "spans": [ + { + "bbox": [ + 443, + 223, + 525, + 234 + ], + "type": "text", + "content": "(b) Sentinel-2 Imagery" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 304, + 238, + 545, + 322 + ], + "lines": [ + { + "bbox": [ + 304, + 238, + 545, + 322 + ], + "spans": [ + { + "bbox": [ + 304, + 238, + 545, + 322 + ], + "type": "text", + "content": "Figure 1: Illustration of partitioning a county into multiple grids at the " + }, + { + "bbox": [ + 304, + 238, + 545, + 322 + ], + "type": "inline_equation", + "content": "9\\mathrm{km}" + }, + { + "bbox": [ + 304, + 238, + 545, + 322 + ], + "type": "text", + "content": " high-resolution. (a) An example of county partitioning, with the red line segments indicating the geometry boundary for the county and the blue line segments representing the high-resolution grids. (b) The resulting satellite images in the Sentinel-2 Imagery, with each composed of " + }, + { + "bbox": [ + 304, + 238, + 545, + 322 + ], + "type": "inline_equation", + "content": "384\\times 384" + }, + { + "bbox": [ + 304, + 238, + 545, + 322 + ], + "type": "text", + "content": " pixels, depicting an area of " + }, + { + "bbox": [ + 304, + 238, + 545, + 322 + ], + "type": "inline_equation", + "content": "9\\times 9\\mathrm{km}" + }, + { + "bbox": [ + 304, + 238, + 545, + 322 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 327, + 545, + 389 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 327, + 545, + 389 + ], + "spans": [ + { + "bbox": [ + 304, + 327, + 545, + 389 + ], + "type": "text", + "content": "orological effect, including growing season weather variations and climate change, on crop yields. Second, we aim to leverage high-resolution satellite images for precise agricultural tracking. The aforementioned three data sources are utilized for achieving our goals." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 394, + 419, + 406 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 394, + 419, + 406 + ], + "spans": [ + { + "bbox": [ + 306, + 394, + 419, + 406 + ], + "type": "text", + "content": "4.1. Problem Statement" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": "We consider the combination of four types of data " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "(\\boldsymbol{x},\\boldsymbol{y}_s,\\boldsymbol{y}_l,\\boldsymbol{z})" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": " for predicting the crop yield at each single U.S. county. Specifically, " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "\\boldsymbol{x} \\in \\mathbb{R}^{T \\times G \\times H \\times W \\times C}" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": " represents satellite images obtained from Sentinel-2 imagery, which capture the information of field crops on the ground. " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "G" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": " indicate the numbers of temporal and spatial data, respectively, whereas " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "H" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "W" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": " are the height, width, and number of channels in the satellite image. " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "\\boldsymbol{y}_s \\in \\mathbb{R}^{T \\times G \\times N_1 \\times d_y}" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "\\boldsymbol{y}_l \\in \\mathbb{R}^{T \\times N_2 \\times d_y}" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": " are meteorological parameters obtained from the HRRR dataset, representing the short-term and the long-term historical data, respectively. Here, " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "N_1" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "N_2" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": " are the numbers of daily and monthly HRRR data points, respectively, and " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "d_y" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": " indicates the number of weather parameters. Note that the short-term meteorological data is the daily HRRR data during the growing season, while the long-term historical meteorological data is the monthly HRRR data from the past several years (e.g., 2018 to 2020 for predicting crop yields in 2021). " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "\\boldsymbol{z} \\in \\mathbb{R}^{d_z}" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": " is the ground-truth crop information obtained from the USDA dataset, with " + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "inline_equation", + "content": "d_z" + }, + { + "bbox": [ + 304, + 413, + 545, + 665 + ], + "type": "text", + "content": " representing the number of parameters for the crop data." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 671, + 380, + 684 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 671, + 380, + 684 + ], + "spans": [ + { + "bbox": [ + 306, + 671, + 380, + 684 + ], + "type": "text", + "content": "4.2. Challenges" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 306, + 689, + 544, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 544, + 712 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 544, + 712 + ], + "type": "text", + "content": "Three challenges exist upon achieving our goals, outlined as follows." + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "5776" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 116, + 74, + 476, + 314 + ], + "blocks": [ + { + "bbox": [ + 116, + 74, + 476, + 314 + ], + "lines": [ + { + "bbox": [ + 116, + 74, + 476, + 314 + ], + "spans": [ + { + "bbox": [ + 116, + 74, + 476, + 314 + ], + "type": "image", + "image_path": "151c8dbafb88e4fed7282f7383b6312254dcc2ee892d00bba8f0323d7cc6bffc.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 183, + 319, + 408, + 332 + ], + "lines": [ + { + "bbox": [ + 183, + 319, + 408, + 332 + ], + "spans": [ + { + "bbox": [ + 183, + 319, + 408, + 332 + ], + "type": "text", + "content": "Figure 2: The architecture of our proposed MMST-ViT." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 338, + 289, + 470 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 338, + 289, + 470 + ], + "spans": [ + { + "bbox": [ + 46, + 338, + 289, + 470 + ], + "type": "text", + "content": "Capturing the Effect of Growing Season Weather Variations on Crop Growth. Previous studies only consider the meteorological data (or the remote sensing data) for crop yield predictions, overlooking the direct impact of growing season weather variations on crop growth. To capture such an impact, we aim to leverage both visual remote sensing and numerical meteorological data. In particular, the Multi-Head Attention (MHA) technique [50] is adopted to capture the meteorological effects on crop growth. However, how to perform multi-modal attention over visual remote sensing data and numerical meteorological data remains open." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 472, + 287, + 603 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 472, + 287, + 603 + ], + "spans": [ + { + "bbox": [ + 46, + 472, + 287, + 603 + ], + "type": "text", + "content": "Lacking a Mechanism for Pre-training Multi-Modal Model. Deep neural networks (DNNs), especially Vision Transformer (ViT)-based models, are prone to overfitting, requiring appropriate pre-training to achieve satisfactory performance. Unfortunately, conventional pretraining techniques (e.g., SimCLR [9]) only marginally improve crop yield prediction performance as they consider the visual data only, ineffective for pre-training multi-modal models. How to pre-train the multi-modal model for satisfactory crop yield predictions is challenging to be addressed." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "content": "Capturing the Impact of Climate Change on Crops. As reported by a prior study [39], the long-term climate change in the atmosphere would gradually decrease the crop yield on the ground. Some studies [28, 15] have demonstrated that taking the climate change effect into account can better crop yield prediction. But their designs overlook the remote sensing data, viewed as essential for precise agricultural tracking. So far, how to develop effective ways to capture the impact of long-term climate change on crop yields" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 305, + 338, + 448, + 350 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 338, + 448, + 350 + ], + "spans": [ + { + "bbox": [ + 305, + 338, + 448, + 350 + ], + "type": "text", + "content": "is challenging and unanswered yet." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 356, + 444, + 369 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 356, + 444, + 369 + ], + "spans": [ + { + "bbox": [ + 305, + 356, + 444, + 369 + ], + "type": "text", + "content": "4.3. Our Proposed Approach" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 374, + 545, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 374, + 545, + 434 + ], + "spans": [ + { + "bbox": [ + 304, + 374, + 545, + 434 + ], + "type": "text", + "content": "To tackle the aforementioned challenges, we develop the Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT) for predicting crop yields at the county level, by leveraging the remote sensing data and the short-term and long-term meteorological data." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 436, + 546, + 638 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 436, + 546, + 638 + ], + "spans": [ + { + "bbox": [ + 304, + 436, + 546, + 638 + ], + "type": "text", + "content": "Model Overview. Our proposed MMST-ViT consists of three key components, i.e., Multi-Modal Transformer, Spatial Transformer, and Temporal Transformer, as shown in Figure 2. The Multi-Modal Transformer is designed to capture the impact of short-term meteorological variations on crop growth, by leveraging the satellite images (i.e., " + }, + { + "bbox": [ + 304, + 436, + 546, + 638 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 304, + 436, + 546, + 638 + ], + "type": "text", + "content": ") and the short-term meteorological parameters (i.e., " + }, + { + "bbox": [ + 304, + 436, + 546, + 638 + ], + "type": "inline_equation", + "content": "\\mathbf{y}_s" + }, + { + "bbox": [ + 304, + 436, + 546, + 638 + ], + "type": "text", + "content": "). The Spatial Transformer then utilizes the output of the Multi-Modal Transformer for learning the global spatial information of a county. Next, the Temporal Transformer combines the outputs of our Spatial Transformer and the long-term meteorological data (i.e., " + }, + { + "bbox": [ + 304, + 436, + 546, + 638 + ], + "type": "inline_equation", + "content": "\\mathbf{y}_l" + }, + { + "bbox": [ + 304, + 436, + 546, + 638 + ], + "type": "text", + "content": ") to capture both global temporal information and the impact of long-term climate change on crop yields. Finally, the output of our Temporal Transformer is used by a linear classifier for predicting the annual crop yields. The details of each component are provided below." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "text", + "content": "Multi-Modal Transformer. Aiming to capture the direct impact of atmospheric weather variations on crop growth, the Multi-Modal Transformer consists of a visual backbone network and a multi-modal attention layer. The former extracts high-quality visual representations from satellite images for accurate agricultural tracking, while the lat" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5777" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "content": "ter captures the relationship between the visual representation and meteorological parameters, to understand the impact of meteorological parameters on crop growth. Let " + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "inline_equation", + "content": "f_{\\theta} \\colon (\\mathbb{R}^{T \\times G \\times H \\times W \\times C}, \\mathbb{R}^{T \\times G \\times N_1 \\times d_y}) \\to \\mathbb{R}^{T \\times G \\times d}" + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "content": " be our Multi-Modal Transformer, with " + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "inline_equation", + "content": "\\pmb{\\theta}" + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "content": " denoting the parameters for DNNs and " + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "content": " representing the dimension for hidden vectors. Notably, all the hidden dimensions in this paper are set to the same size of " + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "content": ". As such, the proposed Multi-Modal Transformer can be expressed as " + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "inline_equation", + "content": "f_{\\theta}(x, y_s) = v_m" + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "inline_equation", + "content": "y_s" + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "content": " are the Sentinel-2 images and the short-term meteorological data, respectively. " + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "inline_equation", + "content": "v_m \\in \\mathbb{R}^{T \\times G \\times d}" + }, + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "content": " is the output of our Multi-Modal Transformer." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 216, + 290, + 407 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 216, + 290, + 407 + ], + "spans": [ + { + "bbox": [ + 46, + 216, + 290, + 407 + ], + "type": "text", + "content": "In this work, we utilize Pyramid Vision Transformer (PVT) [51] as the visual backbone network since it advances ResNet [19] and vanilla ViT [12] respectively by having the global receptive field and by enabling high-resolution feature maps. To capture the direct impact of meteorological parameters on crop growth during the growing season, a naive way is by concatenating visual and numerical representations extracted respectively from the Sentinel-2 images and the meteorological parameters. Unfortunately, our empirical results show that such a naive way cannot achieve satisfactory performance. Inspired by the recent success of multi-head attention mechanisms [50, 12, 40], we devise a novel Multi-Modal Multi-Head Attention (MM-MHA) mechanism to capture the impact of meteorological parameters on crop growth, mathematically expressed as" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 59, + 416, + 263, + 430 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 416, + 263, + 430 + ], + "spans": [ + { + "bbox": [ + 59, + 416, + 263, + 430 + ], + "type": "interline_equation", + "content": "\\operatorname {M M - M H A} (\\boldsymbol {Q}, \\boldsymbol {K}, \\boldsymbol {V}) = \\operatorname {S o f t m a x} (\\boldsymbol {Q} \\boldsymbol {K} ^ {T} / \\sqrt {d}) \\boldsymbol {V},", + "image_path": "56c1383d74c4e356c1b0396fe005fc8c8dfa35792bd8744832d1c3dd7d2280ed.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 75, + 433, + 287, + 447 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 75, + 433, + 287, + 447 + ], + "spans": [ + { + "bbox": [ + 75, + 433, + 287, + 447 + ], + "type": "interline_equation", + "content": "\\boldsymbol {Q} = \\boldsymbol {W} _ {m} ^ {Q} \\cdot \\varphi_ {m} (\\boldsymbol {x}), \\boldsymbol {K} = \\boldsymbol {W} _ {m} ^ {K} \\cdot \\pi_ {m} (\\boldsymbol {y} _ {s}), \\tag {1}", + "image_path": "bd8c58196723990c874282e8acd2e6b10b9308093e69a0ffa987520b0e32c7f2.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 119, + 449, + 204, + 464 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 119, + 449, + 204, + 464 + ], + "spans": [ + { + "bbox": [ + 119, + 449, + 204, + 464 + ], + "type": "interline_equation", + "content": "\\boldsymbol {V} = \\boldsymbol {W} _ {m} ^ {V} \\cdot \\pi_ {m} (\\boldsymbol {y} _ {s}).", + "image_path": "7243ef80999256471f0317347059e30e8fe1789c5734aa95152b9ed1c155b41f.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "spans": [ + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "type": "text", + "content": "Here, " + }, + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "type": "inline_equation", + "content": "\\varphi_{m}(\\pmb{x})\\in \\mathbb{R}^{T\\times G\\times N_{p}\\times d}" + }, + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "type": "text", + "content": " is the visual representation encoded by PVT, with " + }, + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "type": "inline_equation", + "content": "N_{p}" + }, + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "type": "text", + "content": " indicating the number of image patches. " + }, + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "type": "inline_equation", + "content": "\\pi_m(\\pmb {y}_s)\\in \\mathbb{R}^{T\\times G\\times N_1\\times d}" + }, + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "type": "text", + "content": " is the meteorological parameters after the linear projection. Notably, " + }, + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "type": "inline_equation", + "content": "\\pmb{W}_{m}^{Q},\\pmb{W}_{m}^{K}" + }, + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "type": "inline_equation", + "content": "\\pmb{W}_{m}^{V}" + }, + { + "bbox": [ + 46, + 473, + 287, + 581 + ], + "type": "text", + "content": " are learnable projection matrices, similar to those in prior studies [50, 40]. To our knowledge, this is the first attempt at developing a multi-modal multi-attention approach for leveraging both visual remote sensing data and numerical meteorological data." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "type": "text", + "content": "However, ViT-based models are highly sensitive to overfitting, calling for pre-training with millions of visual data [12]. Meanwhile, real-world crop yield prediction usually lacks sufficient crop data for pre-training. Worse still, capturing the impact of short-term weather conditions on crops requires considering both the visual and the numerical data simultaneously. Although self-supervised learning techniques [9, 5, 18] have recently been developed for pretraining DNNs, they cannot tackle the aforementioned issue at the same time. For example, SimCLR [9] fails to address the multi-modal data issue." + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 309, + 76, + 547, + 266 + ], + "blocks": [ + { + "bbox": [ + 309, + 76, + 547, + 266 + ], + "lines": [ + { + "bbox": [ + 309, + 76, + 547, + 266 + ], + "spans": [ + { + "bbox": [ + 309, + 76, + 547, + 266 + ], + "type": "image", + "image_path": "7b2afaaa406c86d2319c255b874242f1998dcb63b74f4614d577a37e2003a470.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 328, + 277, + 523, + 289 + ], + "lines": [ + { + "bbox": [ + 328, + 277, + 523, + 289 + ], + "spans": [ + { + "bbox": [ + 328, + 277, + 523, + 289 + ], + "type": "text", + "content": "Figure 3: Multi-modal self-supervised learning." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "spans": [ + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "text", + "content": "Here, we propose a novel multi-modal self-supervised learning for pre-training our Multi-Modal Transformer without human supervision, which is inspired by SimCLR, but having two differences. First, we utilize the PVT instead of convolutional neural networks (CNNs) as the backbone network since PVT advances CNNs by having a global receptive field [51]. Second, we replace the Multi-Layer Perceptron (MLP) layer in SimCLR with our proposed multimodal self-attention layer (i.e., Eq. (1)) for simultaneously tackling visual and numerical data. Figure 3 illustrates its architecture. Given a satellite image " + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "inline_equation", + "content": "\\pmb{x}^m" + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "text", + "content": " (or " + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "inline_equation", + "content": "\\pmb{x}^n" + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "text", + "content": "), we perform the data augmentation to get its two augmented images, and then feed them to the PVT to get two sets of visual representations. After that, we use our proposed MM-MHA (i.e., Eq. (1)) to perform multi-modal attention between the visual representations and the corresponding short-term parameters " + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "inline_equation", + "content": "\\pmb{y}_s^m" + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "text", + "content": " (or " + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "inline_equation", + "content": "\\pmb{y}_s^n" + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "text", + "content": "), arriving at two sets of output sequences. Here, we regard two sets of output sequences out of a given satellite image (e.g., " + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "inline_equation", + "content": "\\pmb{x}^m" + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "text", + "content": ") as the positive pair. Meanwhile, two sets of output sequences from different satellite images (e.g., " + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "inline_equation", + "content": "\\pmb{x}^m" + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "inline_equation", + "content": "\\pmb{x}^n" + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "text", + "content": ") are regarded as the negative pair. Similar to vanilla ViT [12], the head of output sequences (i.e., the classification token) is taken as the output of our Multi-Modal Transformer, i.e., the hidden vector " + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "inline_equation", + "content": "\\pmb{v}_m" + }, + { + "bbox": [ + 304, + 299, + 547, + 610 + ], + "type": "text", + "content": ". As such, our multi-modal contrastive loss is defined as," + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 314, + 615, + 536, + 644 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 314, + 615, + 536, + 644 + ], + "spans": [ + { + "bbox": [ + 314, + 615, + 536, + 644 + ], + "type": "interline_equation", + "content": "\\ell (i, j) = - \\log \\frac {\\exp (\\operatorname {s i m} \\left(\\boldsymbol {v} _ {m} ^ {i} , \\boldsymbol {v} _ {m} ^ {j}\\right) / \\tau)}{\\sum_ {i \\neq k , k = 1 , \\dots , 2 B} \\exp (\\operatorname {s i m} \\left(\\boldsymbol {v} _ {m} ^ {i} , \\boldsymbol {v} _ {m} ^ {k}\\right) / \\tau)},", + "image_path": "69c4ef69b94d94922e5551a91b62e23484f6a09394c53b59ab6abf657f4915aa.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 340, + 647, + 545, + 689 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 340, + 647, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 340, + 647, + 545, + 689 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {c l}} = \\frac {1}{2 B} \\sum_ {k = 1} ^ {B} [ \\ell (k, k + B) + \\ell (k + B, k) ], \\tag {2}", + "image_path": "43c04931b61dd492c4369ec17514330a987b039cd762b70ed4e2c9423708f8c8.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 689, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 689, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 689, + 546, + 714 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 689, + 546, + 714 + ], + "type": "inline_equation", + "content": "B = T \\times G" + }, + { + "bbox": [ + 304, + 689, + 546, + 714 + ], + "type": "text", + "content": ". Here, " + }, + { + "bbox": [ + 304, + 689, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\pmb{v}_m^i" + }, + { + "bbox": [ + 304, + 689, + 546, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 689, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\pmb{v}_m^j" + }, + { + "bbox": [ + 304, + 689, + 546, + 714 + ], + "type": "text", + "content": " are the positive pair, and " + }, + { + "bbox": [ + 304, + 689, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 304, + 689, + 546, + 714 + ], + "type": "text", + "content": " is the temperature parameter. Intuitively, our" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5778" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": "Eq. (2) encourages two hidden vectors from the same satellite image (i.e., representing the same region) to be similar, and two hidden vectors from different satellite images (i.e., representing different regions) to be dissimilar. As such, we can pre-train our Multi-Modal Transformer to capture the impact of short-term meteorological parameters on crop growth without labor-intensive human supervision." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 158, + 288, + 315 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 158, + 288, + 315 + ], + "spans": [ + { + "bbox": [ + 46, + 158, + 288, + 315 + ], + "type": "text", + "content": "Spatial Transformer. Recall that the Sentinel-2 Imagery dataset of a county is partitioned into multiple fine-grained grids for precise agricultural tracking. To learn spatial dependency among those grids, we propose a Spatial Transformer " + }, + { + "bbox": [ + 46, + 158, + 288, + 315 + ], + "type": "inline_equation", + "content": "g_{\\phi} : \\mathbb{R}^{T \\times G \\times d} \\to \\mathbb{R}^{T \\times d}" + }, + { + "bbox": [ + 46, + 158, + 288, + 315 + ], + "type": "text", + "content": ", whose purpose is to capture the global spatial representations for counties. The design of our Spatial Transformer is inspired by the vanilla ViT [12] but with a flexible number of positional embeddings. It is used to tackle the scenario that the number of grids varies among counties as it depends on county sizes. To learn global spatial information for counties, the Spatial Transformer prepends a learnable classification token " + }, + { + "bbox": [ + 46, + 158, + 288, + 315 + ], + "type": "inline_equation", + "content": "v_{m}^{\\mathrm{cls}} \\in \\mathbb{R}^{T \\times 1 \\times d}" + }, + { + "bbox": [ + 46, + 158, + 288, + 315 + ], + "type": "text", + "content": ", arriving at" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 74, + 318, + 287, + 333 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 318, + 287, + 333 + ], + "spans": [ + { + "bbox": [ + 74, + 318, + 287, + 333 + ], + "type": "interline_equation", + "content": "\\varphi_ {s} \\left(\\boldsymbol {v} _ {m}\\right) = \\left[ \\boldsymbol {v} _ {m} ^ {\\text {c l s}}; \\boldsymbol {v} _ {m} ^ {1}; \\boldsymbol {v} _ {m} ^ {2}; \\dots ; \\boldsymbol {v} _ {m} ^ {G} \\right] + \\mathbf {E} _ {\\text {p o s}}, \\tag {3}", + "image_path": "ea47d3d22fb6b116c9d0a223ec2bcf0f40a981ef49646c3d74dfc3d53554a223.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 338, + 287, + 388 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 338, + 287, + 388 + ], + "spans": [ + { + "bbox": [ + 46, + 338, + 287, + 388 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 338, + 287, + 388 + ], + "type": "inline_equation", + "content": "\\mathbf{E}_{\\mathrm{pos}} \\in \\mathbb{R}^{T \\times (G + 1) \\times d}" + }, + { + "bbox": [ + 46, + 338, + 287, + 388 + ], + "type": "text", + "content": " is the flexible positional embeddings. We propose a Spatial Multi-Head Attention (S-MHA) to learn spatial dependency among grids. Mathematically," + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 70, + 392, + 263, + 407 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 392, + 263, + 407 + ], + "spans": [ + { + "bbox": [ + 70, + 392, + 263, + 407 + ], + "type": "interline_equation", + "content": "\\operatorname {S - M H A} (\\boldsymbol {Q}, \\boldsymbol {K}, \\boldsymbol {V}) = \\operatorname {S o f t m a x} (\\boldsymbol {Q} \\boldsymbol {K} ^ {T} / \\sqrt {d}) \\boldsymbol {V},", + "image_path": "3863cf7b2314595819e85ebe0b646eacf7f6ea3f93ab2acc769bd3e772cbdd20.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 79, + 409, + 287, + 423 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 79, + 409, + 287, + 423 + ], + "spans": [ + { + "bbox": [ + 79, + 409, + 287, + 423 + ], + "type": "interline_equation", + "content": "\\boldsymbol {Q} = \\boldsymbol {W} _ {s} ^ {Q} \\cdot \\varphi_ {s} (\\boldsymbol {v} _ {m}), \\boldsymbol {K} = \\boldsymbol {W} _ {s} ^ {K} \\cdot \\varphi_ {s} (\\boldsymbol {v} _ {m}), \\tag {4}", + "image_path": "c21052eddc31fdd028484a11dd242f6c595f9554ac473a73377b446b756d9f08.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 129, + 426, + 215, + 439 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 129, + 426, + 215, + 439 + ], + "spans": [ + { + "bbox": [ + 129, + 426, + 215, + 439 + ], + "type": "interline_equation", + "content": "\\boldsymbol {V} = \\boldsymbol {W} _ {s} ^ {V} \\cdot \\varphi_ {s} (\\boldsymbol {v} _ {m}).", + "image_path": "0e80946bd825ed0eda0712f10841e601b9cfb02e8a414f953bc183ad9251ec81.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 445, + 287, + 517 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 445, + 287, + 517 + ], + "spans": [ + { + "bbox": [ + 46, + 445, + 287, + 517 + ], + "type": "text", + "content": "Here, " + }, + { + "bbox": [ + 46, + 445, + 287, + 517 + ], + "type": "inline_equation", + "content": "\\boldsymbol{W}_s^Q, \\boldsymbol{W}_s^K, \\boldsymbol{W}_s^V" + }, + { + "bbox": [ + 46, + 445, + 287, + 517 + ], + "type": "text", + "content": " are three learnable matrices, similar to those given in Eq. (1). Finally, we regard the head of output sequences as global spatial representations of counties. That is, we have " + }, + { + "bbox": [ + 46, + 445, + 287, + 517 + ], + "type": "inline_equation", + "content": "g_{\\phi}(\\boldsymbol{v}_m) = \\boldsymbol{v}_s" + }, + { + "bbox": [ + 46, + 445, + 287, + 517 + ], + "type": "text", + "content": ", with " + }, + { + "bbox": [ + 46, + 445, + 287, + 517 + ], + "type": "inline_equation", + "content": "\\boldsymbol{v}_s \\in \\mathbb{R}^{T \\times d}" + }, + { + "bbox": [ + 46, + 445, + 287, + 517 + ], + "type": "text", + "content": " signifying the hidden vector that incorporates global spatial information." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 520, + 287, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 520, + 287, + 604 + ], + "spans": [ + { + "bbox": [ + 46, + 520, + 287, + 604 + ], + "type": "text", + "content": "Temporal Transformer. The Temporal Transformer possesses two goals. The first goal aims to learn temporal dependency among the hidden vectors " + }, + { + "bbox": [ + 46, + 520, + 287, + 604 + ], + "type": "inline_equation", + "content": "\\boldsymbol{v}_s" + }, + { + "bbox": [ + 46, + 520, + 287, + 604 + ], + "type": "text", + "content": ", i.e., the outputs of our Spatial Transformer. The second goal is to capture the effect of long-term climate change on crop yields. To achieve the first goal, we add a classification token " + }, + { + "bbox": [ + 46, + 520, + 287, + 604 + ], + "type": "inline_equation", + "content": "\\boldsymbol{v}_s^{\\mathrm{cls}}" + }, + { + "bbox": [ + 46, + 520, + 287, + 604 + ], + "type": "text", + "content": " for learning the global temporal representation, i.e.," + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 78, + 609, + 287, + 623 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 78, + 609, + 287, + 623 + ], + "spans": [ + { + "bbox": [ + 78, + 609, + 287, + 623 + ], + "type": "interline_equation", + "content": "\\varphi_ {t} \\left(\\boldsymbol {v} _ {s}\\right) = \\left[ \\boldsymbol {v} _ {s} ^ {\\text {c l s}}; \\boldsymbol {v} _ {s} ^ {1}; \\boldsymbol {v} _ {s} ^ {2}; \\dots ; \\boldsymbol {v} _ {s} ^ {T} \\right] + \\mathbf {E} _ {\\text {t m p}}, \\tag {5}", + "image_path": "22f646fb63c1617b53afb4c36e166c8359f669b6ce717c15ebbb844f412c9edb.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{E}_{\\mathrm{tmp}} \\in \\mathbb{R}^{(T + 1) \\times d}" + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "content": " is the temporal embedding, similar to the positional embeddings " + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{E}_{\\mathrm{pos}}" + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "content": " expressed in Eq. (3). The novel Temporal Multi-Head Attention (T-MHA) is also devised to capture the impact of long-term historical meteorological parameters on crop yields. Its key idea is to incorporate a relative meteorological bias into each head for similarity computation, motivated by prior studies [6, 38, 33]." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 72, + 506, + 84 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 506, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 506, + 84 + ], + "type": "text", + "content": "Mathematically, our T-MHA can be expressed by" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 310, + 94, + 544, + 152 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 94, + 544, + 152 + ], + "spans": [ + { + "bbox": [ + 310, + 94, + 544, + 152 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\operatorname {T} - \\operatorname {M H A} (\\boldsymbol {Q}, \\boldsymbol {K}, \\boldsymbol {V}) = \\operatorname {S o f t m a x} (\\boldsymbol {Q} \\boldsymbol {K} ^ {\\boldsymbol {T}} / \\sqrt {d} + \\pi_ {t} (\\boldsymbol {y} _ {l})) \\boldsymbol {V}, \\\\ \\boldsymbol {Q} = \\boldsymbol {W} _ {t} ^ {Q} \\cdot \\varphi_ {t} (\\boldsymbol {v} _ {s}), \\boldsymbol {K} = \\boldsymbol {W} _ {t} ^ {K} \\cdot \\varphi_ {t} (\\boldsymbol {v} _ {s}), \\\\ \\boldsymbol {V} = \\boldsymbol {W} _ {t} ^ {V} \\cdot \\varphi_ {t} (\\boldsymbol {v} _ {s}). \\tag {6} \\\\ \\end{array}", + "image_path": "3b970cd9cea922767a5500e11ba33906de6c50821d755e19c8f4c4d89462cd02.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "spans": [ + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "text", + "content": "Here, " + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "inline_equation", + "content": "\\pmb{y}_l" + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "text", + "content": " represents the long-term meteorological parameters, and " + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "inline_equation", + "content": "\\pi_t(\\cdot)" + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "text", + "content": " is a linear projection layer. Similarly, " + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "inline_equation", + "content": "\\pmb{W}_t^Q" + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "inline_equation", + "content": "\\pmb{W}_t^K" + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "inline_equation", + "content": "\\pmb{W}_t^V" + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "text", + "content": " are three learnable matrices. In summary, our Temporal Transformer " + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "inline_equation", + "content": "h_\\psi : (\\mathbb{R}^{T \\times d}, \\mathbb{R}^{T \\times N_2 \\times d_y}) \\to \\mathbb{R}^d" + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "text", + "content": " can be defined as " + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "inline_equation", + "content": "h_\\psi(\\pmb{v}_s, \\pmb{y}_l) = \\pmb{v}_t" + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "text", + "content": ", with " + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "inline_equation", + "content": "\\pmb{v}_t \\in \\mathbb{R}^d" + }, + { + "bbox": [ + 304, + 152, + 545, + 247 + ], + "type": "text", + "content": " being the hidden vector that incorporates both global temporal information and the impact of climate change on crops simultaneously." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "spans": [ + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "type": "text", + "content": "Finally, the hidden vector " + }, + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "type": "inline_equation", + "content": "\\pmb{v}_t" + }, + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "type": "text", + "content": " is fed into a linear classifier for crop yield predictions, i.e., " + }, + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "type": "inline_equation", + "content": "\\hat{\\pmb{z}} = \\pmb{W}^T\\pmb{v}_t + \\pmb{b}" + }, + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "type": "text", + "content": ", with " + }, + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "type": "inline_equation", + "content": "\\pmb{W}" + }, + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "type": "inline_equation", + "content": "\\pmb{b}" + }, + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "type": "text", + "content": " respectively denoting the weights and the bias for the classifier, and " + }, + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "type": "inline_equation", + "content": "\\hat{\\pmb{z}} \\in \\mathbb{R}^{d_z}" + }, + { + "bbox": [ + 304, + 248, + 545, + 297 + ], + "type": "text", + "content": " indicating the crop yield prediction." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 307, + 387, + 320 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 307, + 387, + 320 + ], + "spans": [ + { + "bbox": [ + 306, + 307, + 387, + 320 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 327, + 545, + 388 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 327, + 545, + 388 + ], + "spans": [ + { + "bbox": [ + 304, + 327, + 545, + 388 + ], + "type": "text", + "content": "We conduct experiments for the county-level crop yield predictions across four U.S. states, i.e., Mississippi (MS), Louisiana (LA), Iowa (IA), and Illinois (IL). Four types of crops, i.e., corn, cotton, soybean, and winter wheat, are taken into account for performance evaluation." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 395, + 432, + 407 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 395, + 432, + 407 + ], + "spans": [ + { + "bbox": [ + 306, + 395, + 432, + 407 + ], + "type": "text", + "content": "5.1. Experimental Settings" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 416, + 545, + 488 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 416, + 545, + 488 + ], + "spans": [ + { + "bbox": [ + 304, + 416, + 545, + 488 + ], + "type": "text", + "content": "Datasets. We utilize the Sentinel-2 imagery and the daily HRRR data datasets during the growing season respectively as the remote sensing data and the short-term meteorological data. Meanwhile, the monthly HRRR data from the previous three years are used as the long-term meteorological parameters." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 491, + 545, + 599 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 491, + 545, + 599 + ], + "spans": [ + { + "bbox": [ + 304, + 491, + 545, + 599 + ], + "type": "text", + "content": "Compared Approaches. We compare our proposed MMST-ViT to three DL-based approaches, with one, i.e., ConvLSTM [43], developed for spatial-temporal prediction, and the other two, i.e., CNN-RNN [28] and GNN-RNN [15], developed for crop yield predictions. Minor rectifications are made to them so that they can admit the Sentinel-2 imagery and HRRR datasets as their inputs. Other hyperparameters, unless specified otherwise, are set to the values as those reported in their original studies." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 602, + 545, + 662 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 602, + 545, + 662 + ], + "spans": [ + { + "bbox": [ + 304, + 602, + 545, + 662 + ], + "type": "text", + "content": "Metrics. We take three performance metrics, i.e., Root Mean Square Error (RMSE), R-squared " + }, + { + "bbox": [ + 304, + 602, + 545, + 662 + ], + "type": "inline_equation", + "content": "(\\mathbf{R}^2)" + }, + { + "bbox": [ + 304, + 602, + 545, + 662 + ], + "type": "text", + "content": ", and Pearson Correlation Coefficient (Corr), for comparative evaluation. Notably, a lower value of RMSE or a higher value of " + }, + { + "bbox": [ + 304, + 602, + 545, + 662 + ], + "type": "inline_equation", + "content": "\\mathbf{R}^2" + }, + { + "bbox": [ + 304, + 602, + 545, + 662 + ], + "type": "text", + "content": " (or Corr) indicates better performance." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "content": "Model Size. Our proposed MMST-ViT builds on the top of Vision Transformer (ViT) [12]. Similar to ViT, it consists of a stack of Transformer blocks [50], where each Transformer block includes a Multi-Head Attention (MHA) block and" + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "5779" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 55, + 89, + 538, + 141 + ], + "blocks": [ + { + "bbox": [ + 214, + 71, + 378, + 83 + ], + "lines": [ + { + "bbox": [ + 214, + 71, + 378, + 83 + ], + "spans": [ + { + "bbox": [ + 214, + 71, + 378, + 83 + ], + "type": "text", + "content": "Table 2: Model details used in our study" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 55, + 89, + 538, + 141 + ], + "lines": [ + { + "bbox": [ + 55, + 89, + 538, + 141 + ], + "spans": [ + { + "bbox": [ + 55, + 89, + 538, + 141 + ], + "type": "table", + "html": "
ModelLayerHidden SizeHeadMLP SizeOthers
Multi-Modal TransformerPVT-T/4{2, 2, 2, 2}{64, 128, 320, 512}{1, 2, 5, 8}{512, 1024, 1280, 2048}SR Ratios = {8, 4, 2, 1}
MM-MHA251282048Context Size = 9
Spatial TransformerS-MHA451232048-
Temporal TransformerT-MHA451232048Context Size = 9
", + "image_path": "695b3b38b8049bb50d0073051c0e8796514033e863b860b371021d11ba54fc85.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "table", + "bbox": [ + 56, + 175, + 538, + 247 + ], + "blocks": [ + { + "bbox": [ + 46, + 148, + 546, + 173 + ], + "lines": [ + { + "bbox": [ + 46, + 148, + 546, + 173 + ], + "spans": [ + { + "bbox": [ + 46, + 148, + 546, + 173 + ], + "type": "text", + "content": "Table 3: Overall comparative crop yield predictions for 2021, with the best results shown in bold. Cotton yields are measured in pounds per acre (LB/AC), whereas other crop yields are measured in bushels per acre (BU/AC)" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 56, + 175, + 538, + 247 + ], + "lines": [ + { + "bbox": [ + 56, + 175, + 538, + 247 + ], + "spans": [ + { + "bbox": [ + 56, + 175, + 538, + 247 + ], + "type": "table", + "html": "
MethodCornCottonSoybeanWinter Wheat
RMSE (↓)R2(↑)Corr (↑)RMSE (↓)R2(↑)Corr (↑)RMSE (↓)R2(↑)Corr (↑)RMSE (↓)R2(↑)Corr (↑)
ConvLSTM18.60.6110.78265.40.7150.8467.20.6160.7857.40.5110.715
CNN-RNN14.60.7050.83969.50.6530.8085.80.7030.8397.50.6140.783
GNN-RNN14.20.7300.85458.50.6470.8045.40.7480.8656.00.6210.788
Ours10.50.8110.90042.40.7900.8893.90.8430.9184.60.7850.886
", + "image_path": "3bbf08fddb1f17bb1385ad70121a6dc2081400a0d3ddb47949288bdc45bb2fd9.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_body" + } + ], + "index": 3 + }, + { + "bbox": [ + 45, + 259, + 288, + 390 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 259, + 288, + 390 + ], + "spans": [ + { + "bbox": [ + 45, + 259, + 288, + 390 + ], + "type": "text", + "content": "an MLP block, and both of which incorporate the LayerNorm [4] for normalization. Table 2 presents the details of model sizes used in our experiments. Note that \"PVT-T/4\" refers to the PVT-Tiny model with a patch size of 4, and \"SR Ratios\" represents the spatial reduction ratio in PVT. Following the original PVT [51], we divide the PVT backbone into four stages and report the corresponding model sizes at each stage in the second row of Table 2. The other transformers are single-stage, similar to the vanilla ViT [12]. Notably, \"Context Size\" represents the number of meteorological parameters used in our study." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "spans": [ + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "text", + "content": "Hyperparameters. Our model is pre-trained for 200 epochs using AdamW [35] with " + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "inline_equation", + "content": "\\beta_{1} = 0.9" + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "inline_equation", + "content": "\\beta_{2} = 0.95" + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "text", + "content": ", a weight decay of 0.05, and a cosine decay schedule [34] with an initial learning rate of " + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "inline_equation", + "content": "1e - 4" + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "text", + "content": ", and warmup epochs of 20. To perform data augmentation for pre-training, various techniques such as random cropping, random horizontal flipping, random Gaussian blur, and color jittering are employed. These techniques are similar to those used in SimCLR [9]. After pre-training, we fine-tune our proposed MMST-ViT for 100 epochs using AdamW with " + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "inline_equation", + "content": "\\beta_{1} = 0.9" + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "inline_equation", + "content": "\\beta_{2} = 0.999" + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "text", + "content": ", a cosine decay schedule with an initial learning rate of " + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "inline_equation", + "content": "1e - 3" + }, + { + "bbox": [ + 46, + 396, + 287, + 539 + ], + "type": "text", + "content": ", and warmup epochs of 5." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 549, + 248, + 562 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 549, + 248, + 562 + ], + "spans": [ + { + "bbox": [ + 47, + 549, + 248, + 562 + ], + "type": "text", + "content": "5.2. Comparative Performance Evaluation" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 568, + 287, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 568, + 287, + 616 + ], + "spans": [ + { + "bbox": [ + 46, + 568, + 287, + 616 + ], + "type": "text", + "content": "We conduct experiments for predicting 2021 crop yields at the county level across four aforementioned U.S. states, with prediction performance measured by the three metrics of RMSE, " + }, + { + "bbox": [ + 46, + 568, + 287, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{R}^2" + }, + { + "bbox": [ + 46, + 568, + 287, + 616 + ], + "type": "text", + "content": ", and Corr." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "text", + "content": "Table 3 lists the comparative performance results of our MMST-ViT and its three counterparts, i.e., ConvLSTM, CNN-RNN, and GNN-RNN. Four observations are obtained from the table. First, our approach achieves the best performance under all metrics. In particular, for the soybean yield prediction, our approach achieves the lowest RMSE of 3.9 and the highest " + }, + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "inline_equation", + "content": "R^2" + }, + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "text", + "content": " (or Corr) of 0.843 (or 0.918). With the lowest RMSE value, our predicted soybean" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 259, + 547, + 511 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 259, + 547, + 511 + ], + "spans": [ + { + "bbox": [ + 304, + 259, + 547, + 511 + ], + "type": "text", + "content": "yields are the closest to the actual amounts. In addition, the highest " + }, + { + "bbox": [ + 304, + 259, + 547, + 511 + ], + "type": "inline_equation", + "content": "\\mathbb{R}^2" + }, + { + "bbox": [ + 304, + 259, + 547, + 511 + ], + "type": "text", + "content": " and Corr values demonstrate that our predicted soybean yields are best correlated to actual figures. Second, our approach significantly outperforms ConvLSTM, with its RMSE values always lower than those of ConvLSTM markedly, ranging from 2.8 (for winter wheat) to 23.0 (for cotton). The reason is that ConvLSTM overlooks the impact of meteorological parameters on crop growth. Third, CNN-RNN underperforms our approach by 4.1 (for corn), by 27.1 (for cotton), by 1.9 (for soybean), and by 2.9 (for winter wheat), in terms of RMSE, though both models take into account the effect of long-term climate change on crop yields. Because CNN-RNN cannot model the spatial dependency among neighborhood regions. Fourth, MMST-ViT outperforms the most recent state-of-the-art (i.e., GNN-RNN) measurably. Specifically, our RMSE value is lower by 16.1 for cotton, whereas our " + }, + { + "bbox": [ + 304, + 259, + 547, + 511 + ], + "type": "inline_equation", + "content": "\\mathbb{R}^2" + }, + { + "bbox": [ + 304, + 259, + 547, + 511 + ], + "type": "text", + "content": " and Corr values are better respectively by 0.165 and 0.098 for winter wheat. These results are contributed by leveraging both visual remote sensing and numerical meteorological data in our model, while GNN-RNN only considers the meteorological data." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 525, + 520, + 538 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 525, + 520, + 538 + ], + "spans": [ + { + "bbox": [ + 305, + 525, + 520, + 538 + ], + "type": "text", + "content": "5.3. Visualizing Crop Yield Prediction Errors" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "text", + "content": "In this section, we conduct experiments to visualize crop yield prediction errors across four U.S. states: Mississippi (MS), Louisiana (LA), Iowa (IA), and Illinois (IL). We use the same experimental settings as those stated in Section 5.2. Figure 4 shows the absolute prediction errors for soybean across counties/parishes in the four states, with navy blue and light blue respectively indicating the high and low absolute errors. Our MMST-ViT model is highly effective in predicting crop yields, with the absolute prediction errors of " + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "inline_equation", + "content": "57.2\\%" + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "text", + "content": " counties below 3 BU/AC. Furthermore, we discover that " + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "inline_equation", + "content": "95.1\\%" + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "text", + "content": " of counties in MS, " + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "inline_equation", + "content": "92.5\\%" + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "text", + "content": " of parishes in LA, " + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "inline_equation", + "content": "86.8\\%" + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "text", + "content": " of counties in IA, and " + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "inline_equation", + "content": "91.0\\%" + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "text", + "content": " of counties in IL achieve decent absolute prediction errors (i.e., " + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "inline_equation", + "content": "\\leq 6" + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "text", + "content": " BU/AC). These empirical findings validate the robustness of MMST-" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5780" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 71, + 70, + 167, + 159 + ], + "blocks": [ + { + "bbox": [ + 71, + 70, + 167, + 159 + ], + "lines": [ + { + "bbox": [ + 71, + 70, + 167, + 159 + ], + "spans": [ + { + "bbox": [ + 71, + 70, + 167, + 159 + ], + "type": "image", + "image_path": "1d956d0f443ff02eb3c3de0c0df4b4f9e29d5c5b3ef47f1fc674f60ffed88d87.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 70, + 165, + 147, + 177 + ], + "lines": [ + { + "bbox": [ + 70, + 165, + 147, + 177 + ], + "spans": [ + { + "bbox": [ + 70, + 165, + 147, + 177 + ], + "type": "text", + "content": "(a) Mississippi (MS)" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 182, + 70, + 284, + 159 + ], + "blocks": [ + { + "bbox": [ + 182, + 70, + 284, + 159 + ], + "lines": [ + { + "bbox": [ + 182, + 70, + 284, + 159 + ], + "spans": [ + { + "bbox": [ + 182, + 70, + 284, + 159 + ], + "type": "image", + "image_path": "a20a4814dbeb98971c8420c01c0b1476f491d2a264d5b104b5965ccda583e431.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 195, + 166, + 265, + 177 + ], + "lines": [ + { + "bbox": [ + 195, + 166, + 265, + 177 + ], + "spans": [ + { + "bbox": [ + 195, + 166, + 265, + 177 + ], + "type": "text", + "content": "(b) Louisiana (LA)" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 186, + 547, + 211 + ], + "lines": [ + { + "bbox": [ + 46, + 186, + 547, + 211 + ], + "spans": [ + { + "bbox": [ + 46, + 186, + 547, + 211 + ], + "type": "text", + "content": "Figure 4: Illustration of absolute prediction errors for soybean across four U.S. states. Note that a county/parish with " + }, + { + "bbox": [ + 46, + 186, + 547, + 211 + ], + "type": "inline_equation", + "content": "< 0" + }, + { + "bbox": [ + 46, + 186, + 547, + 211 + ], + "type": "text", + "content": " indicates its soybean yield data is unavailable." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 293, + 71, + 405, + 159 + ], + "blocks": [ + { + "bbox": [ + 293, + 71, + 405, + 159 + ], + "lines": [ + { + "bbox": [ + 293, + 71, + 405, + 159 + ], + "spans": [ + { + "bbox": [ + 293, + 71, + 405, + 159 + ], + "type": "image", + "image_path": "9f48bfe618aec09d00e9ca2aa12c65b24bc4068d39246a24a9a52780825238bd.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 327, + 166, + 376, + 176 + ], + "lines": [ + { + "bbox": [ + 327, + 166, + 376, + 176 + ], + "spans": [ + { + "bbox": [ + 327, + 166, + 376, + 176 + ], + "type": "text", + "content": "(c) Iowa (IA)" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 435, + 71, + 527, + 159 + ], + "blocks": [ + { + "bbox": [ + 435, + 71, + 527, + 159 + ], + "lines": [ + { + "bbox": [ + 435, + 71, + 527, + 159 + ], + "spans": [ + { + "bbox": [ + 435, + 71, + 527, + 159 + ], + "type": "image", + "image_path": "3471bae2b18dc576cc4955b1861ea12ba673c9f35f7db00c4b7c95bfd467e959.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 444, + 166, + 501, + 176 + ], + "lines": [ + { + "bbox": [ + 444, + 166, + 501, + 176 + ], + "spans": [ + { + "bbox": [ + 444, + 166, + 501, + 176 + ], + "type": "text", + "content": "(d) Illinois (IL)" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 222, + 212, + 234 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 222, + 212, + 234 + ], + "spans": [ + { + "bbox": [ + 47, + 222, + 212, + 234 + ], + "type": "text", + "content": "ViT across various geographic locations." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 240, + 278, + 252 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 240, + 278, + 252 + ], + "spans": [ + { + "bbox": [ + 47, + 240, + 278, + 252 + ], + "type": "text", + "content": "5.4. Performance of One Year Ahead Predictions" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 259, + 287, + 462 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 259, + 287, + 462 + ], + "spans": [ + { + "bbox": [ + 46, + 259, + 287, + 462 + ], + "type": "text", + "content": "In practice, predicting crop yields well in advance of harvest, can provide valuable information for farmers, agribusinesses, and governments in their agricultural planning and decision-making processes. This information can be used to elevate agricultural resilience and sustainability, make informed financial decisions, and support global food security [23]. A prior study [15] simulated the early prediction scenario by masking partial inputs, successfully making predictions several months before harvest. In this study, we attempt a step further by making crop yield predictions one year before the harvest. In particular, we leverage remote sensing and short-term meteorological data during the growing season in the current year to predict crop yields in the next year. For example, the Sentinel-2 imagery and daily HRRR data during the growing season in 2020 are utilized as remote sensing data and the short-term meteorological data for predicting crop yields in 2021." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "spans": [ + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "type": "text", + "content": "Figure 5 illustrates the experimental results. It is observed that our MMST-ViT outperforms three baseline models, i.e., ConvLSTM, CNN-RNN, and GNN-RNN, for the predictions of one year ahead. Among all crops, MMST-ViT achieves the lowest RMSE values ranging from 4.7 (for soybean) to 50.2 (for cotton), the highest " + }, + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "type": "inline_equation", + "content": "\\mathbb{R}^2" + }, + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "type": "text", + "content": " values ranging from 0.711 (for winter wheat) to 0.792 (for soybean), and the highest Corr values ranging from 0.843 (for winter wheat) to 0.890 (for soybean). Additionally, compared to its in-season prediction results (see the 6th row of Table 3), the one year ahead prediction outcomes of our approach are just slightly inferior, degraded respectively by " + }, + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "type": "inline_equation", + "content": "8.6\\%" + }, + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "type": "text", + "content": ", of " + }, + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "type": "inline_equation", + "content": "15.5\\%" + }, + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "type": "text", + "content": ", of " + }, + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "type": "inline_equation", + "content": "17.0\\%" + }, + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "type": "text", + "content": ", and of " + }, + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "type": "inline_equation", + "content": "14.6\\%" + }, + { + "bbox": [ + 46, + 463, + 287, + 641 + ], + "type": "text", + "content": " in terms of RMSE for corn, cotton, soybean, and winter wheat. The empirical results confirm the robustness of MMST-ViT." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 642, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 287, + 713 + ], + "type": "text", + "content": "Interestingly, we also observe that the prediction results for the cotton have a high RMSE value but not a low " + }, + { + "bbox": [ + 46, + 642, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathbb{R}^2" + }, + { + "bbox": [ + 46, + 642, + 287, + 713 + ], + "type": "text", + "content": " (or Corr) value. This is because the cotton yield is measured by pounds per acre (LB/AC), with a high standard deviation value of 250.1, while other crop yields are measured by bushels per acre (BU/AC), with low standard deviation val" + } + ] + } + ], + "index": 13 + }, + { + "type": "table", + "bbox": [ + 308, + 262, + 544, + 367 + ], + "blocks": [ + { + "bbox": [ + 305, + 220, + 545, + 256 + ], + "lines": [ + { + "bbox": [ + 305, + 220, + 545, + 256 + ], + "spans": [ + { + "bbox": [ + 305, + 220, + 545, + 256 + ], + "type": "text", + "content": "Table 4: Ablation studies for different components, with five scenarios considered and the last row listing the results of MMST-ViT" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 308, + 262, + 544, + 367 + ], + "lines": [ + { + "bbox": [ + 308, + 262, + 544, + 367 + ], + "spans": [ + { + "bbox": [ + 308, + 262, + 544, + 367 + ], + "type": "table", + "html": "
ComponentCornSoybean
RMSE (↓)Corr (↑)RMSE (↓)Corr (↑)
Temporal Transformerw/o long-term14.50.8436.20.850
w/o T-MHA15.70.8205.60.839
Spatial Transformerw/o S-MHA13.50.8565.60.849
Multi-Modal Transformerw/o short-term13.60.8396.10.845
w/o image15.20.8096.80.822
MMST-ViT-10.50.9003.90.918
", + "image_path": "e2267f048c2c24bb76f7c29b4c13071e3d66313e28e71cad3dca2126e431ca69.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "table_body" + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 381, + 545, + 430 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 381, + 545, + 430 + ], + "spans": [ + { + "bbox": [ + 305, + 381, + 545, + 430 + ], + "type": "text", + "content": "ues (e.g., 11.8 for soybean). In scenarios with high variance data, the RMSE value may worsen due to larger residuals, while the " + }, + { + "bbox": [ + 305, + 381, + 545, + 430 + ], + "type": "inline_equation", + "content": "\\mathbf{R}^2" + }, + { + "bbox": [ + 305, + 381, + 545, + 430 + ], + "type": "text", + "content": " value improves due to the increased proportion of explained variance." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 438, + 406, + 450 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 438, + 406, + 450 + ], + "spans": [ + { + "bbox": [ + 306, + 438, + 406, + 450 + ], + "type": "text", + "content": "5.5. Ablation Studies" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 461, + 545, + 664 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 461, + 545, + 664 + ], + "spans": [ + { + "bbox": [ + 304, + 461, + 545, + 664 + ], + "type": "text", + "content": "Key Components. We next conduct experiments to show how each key component in our MMST-ViT affects prediction performance. Table 4 lists the results of our ablation studies under five different scenarios, with one shown in a row. Here, \"w/o long-term\" indicates masking the long-term meteorological data, and \"w/o T-MHA\" represents the absence of our Temporal Transformer and instead resorting to the average pooling to obtain the global temporal representation. Similarly, \"w/o S-MHA\" denotes utilizing the average pooling to obtain the global spatial representation. The scenarios of \"w/o short-term\" and \"w/o image\" represent respectively masking the short-term meteorological data and the remote sensing data from the Multi-Modal Transformer. Note that masking either data makes our model unable to conduct MM-MHA, following Eq. (1). The results of our complete MMST-ViT outcomes are shown in the last row of Table 4." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "Three observations can be made from Table 4. First, the long-term meteorological data degrades the Corr value by 0.057 (or 0.068) for corn (or soybean). This validates that crop yield prediction accuracy can benefit from histori" + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 314, + 757 + ], + "type": "text", + "content": "5781" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 71, + 200, + 180 + ], + "blocks": [ + { + "bbox": [ + 50, + 71, + 200, + 180 + ], + "lines": [ + { + "bbox": [ + 50, + 71, + 200, + 180 + ], + "spans": [ + { + "bbox": [ + 50, + 71, + 200, + 180 + ], + "type": "image", + "image_path": "5abb09dbcdc3fcf16fb337d1991bb01de120a1221fa2d52f42cf2d9c51aacbfe.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 104, + 188, + 143, + 198 + ], + "lines": [ + { + "bbox": [ + 104, + 188, + 143, + 198 + ], + "spans": [ + { + "bbox": [ + 104, + 188, + 143, + 198 + ], + "type": "text", + "content": "(a) RMSE" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 209, + 71, + 360, + 182 + ], + "blocks": [ + { + "bbox": [ + 209, + 71, + 360, + 182 + ], + "lines": [ + { + "bbox": [ + 209, + 71, + 360, + 182 + ], + "spans": [ + { + "bbox": [ + 209, + 71, + 360, + 182 + ], + "type": "image", + "image_path": "301bb5ac0757881f7c7e642ca0cefbee658c57c8b9bc4ef9cd5d4f8be09de8f1.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 272, + 187, + 297, + 198 + ], + "lines": [ + { + "bbox": [ + 272, + 187, + 297, + 198 + ], + "spans": [ + { + "bbox": [ + 272, + 187, + 297, + 198 + ], + "type": "text", + "content": "(b) " + }, + { + "bbox": [ + 272, + 187, + 297, + 198 + ], + "type": "inline_equation", + "content": "\\mathbf{R}^2" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 203, + 545, + 228 + ], + "lines": [ + { + "bbox": [ + 46, + 203, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 46, + 203, + 545, + 228 + ], + "type": "text", + "content": "Figure 5: Illustration of the performance for predictions of one year ahead under (a) RMSE, (b) " + }, + { + "bbox": [ + 46, + 203, + 545, + 228 + ], + "type": "inline_equation", + "content": "\\mathbb{R}^2" + }, + { + "bbox": [ + 46, + 203, + 545, + 228 + ], + "type": "text", + "content": ", and (c) Corr, with the cotton yield measured by LB/AC and other crop yields measured by BU/AC." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 371, + 72, + 521, + 182 + ], + "blocks": [ + { + "bbox": [ + 371, + 72, + 521, + 182 + ], + "lines": [ + { + "bbox": [ + 371, + 72, + 521, + 182 + ], + "spans": [ + { + "bbox": [ + 371, + 72, + 521, + 182 + ], + "type": "image", + "image_path": "2c95e90e2b35bedf7a8f2b2f39fc5e00c6a9db14f757b8797ea9ee5e12ac9fe2.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 430, + 188, + 461, + 198 + ], + "lines": [ + { + "bbox": [ + 430, + 188, + 461, + 198 + ], + "spans": [ + { + "bbox": [ + 430, + 188, + 461, + 198 + ], + "type": "text", + "content": "(c) Corr" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 239, + 288, + 383 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 239, + 288, + 383 + ], + "spans": [ + { + "bbox": [ + 46, + 239, + 288, + 383 + ], + "type": "text", + "content": "ical meteorological data, which dictates long-term climate change. Second, the absence of either the Temporal Transformer or the Spatial Transformer lowers the Corr value by 0.080 (for corn) and by 0.069 (for soybean), respectively. Third, unable to conduct MM-MHA as the result of masking the short-term meteorological data or the satellite images degrades prediction performance greatly. For example, masking the short-term meteorological data (or satellite images) causes the Corr value degradation by 0.096 (or 0.073) for soybean. This statistical evidence exhibits the importance of our Multi-Modal Transformer for capturing the impact of meteorological parameters on crop growth." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 391, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 391, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 391, + 288, + 714 + ], + "type": "text", + "content": "Pre-training Techniques. We conduct experiments to explore the impact of our proposed multi-modal self-supervised pre-training, i.e., Eq. (2), on the crop yield prediction. We consider three scenarios, i.e., MMST-ViT without pre-training, with the pre-training technique described in SimCLR [9], and with our multi-modal pre-training. Table 5 presents the prediction performance outcomes. The table reveals that our MMST-ViT (w/ our multi-modal pretraining) significantly outperforms its counterpart (w/o pretraining), exhibiting a lower RMSE value by 2.7 (or 1.2) and a larger Corr value by 0.043 (or 0.043) for corn (or soybean), due to two reasons. First, Vision Transformer (ViT)-based models are prone to overfitting [12], but our multi-modal self-supervised learning can significantly mitigate this issue by leveraging both visual remote sensing data and numerical meteorological data for pre-training. Second, our multi-modal self-supervised pre-training may can capture the impact of meteorological parameters on the crops. In contrast, pre-training our MMST-ViT with the SimCLR technique only achieves marginal performance improvement (compared to the one w/o pre-training), achieving the Corr improvement of 0.001 (0.875 v.s. 0.876) for soybean. This is because the SimCLR technique fails to leverage numerical meteorological parameters for pre-training. These empirical results validate the necessity and importance of our proposed multi-modal pre-training for accurate crop yield predictions." + } + ] + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 308, + 267, + 544, + 326 + ], + "blocks": [ + { + "bbox": [ + 305, + 237, + 545, + 262 + ], + "lines": [ + { + "bbox": [ + 305, + 237, + 545, + 262 + ], + "spans": [ + { + "bbox": [ + 305, + 237, + 545, + 262 + ], + "type": "text", + "content": "Table 5: Ablation studies for different pre-training techniques, with three scenarios considered" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 308, + 267, + 544, + 326 + ], + "lines": [ + { + "bbox": [ + 308, + 267, + 544, + 326 + ], + "spans": [ + { + "bbox": [ + 308, + 267, + 544, + 326 + ], + "type": "table", + "html": "
MethodCornSoybean
RMSE (↓)Corr (↑)RMSE (↓)Corr (↑)
w/o pretraining13.20.8575.10.875
w/ SimCLR12.90.8574.90.876
w/ multi-modal pretraining10.50.9003.90.918
", + "image_path": "c106bbd7d829d05f4f6604cda5e8a849aa17c19b8ce8dd7edc5e153c82b838e4.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 338, + 378, + 350 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 338, + 378, + 350 + ], + "spans": [ + { + "bbox": [ + 306, + 338, + 378, + 350 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 361, + 545, + 600 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 361, + 545, + 600 + ], + "spans": [ + { + "bbox": [ + 304, + 361, + 545, + 600 + ], + "type": "text", + "content": "This paper has proposed the Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), a climate change-aware deep learning approach for predicting crop yields at the county level across the United States. MMST-ViT comprises three key components of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer. Three innovative Multi-Head Attention (MHA) mechanisms are introduced, one for each component. As a result, our MMST-ViT can leverage both the visual remote sensing data and the numerical meteorological data for capturing the impact of short-term growing season weather variations and long-term climate change on crop yields. Additionally, a novel multi-modal contrastive learning technique has been developed, able to effectively pre-train our model without the need of human supervision. We have conducted extensive experiments on " + }, + { + "bbox": [ + 304, + 361, + 545, + 600 + ], + "type": "inline_equation", + "content": "200+" + }, + { + "bbox": [ + 304, + 361, + 545, + 600 + ], + "type": "text", + "content": " counties/parishes located in 4 U.S. states, with the results demonstrating that our proposed MMST-ViT substantially outperforms its state-of-the-art counterparts consistently under three performance metrics of interest." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 619, + 403, + 632 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 619, + 403, + 632 + ], + "spans": [ + { + "bbox": [ + 306, + 619, + 403, + 632 + ], + "type": "text", + "content": "Acknowledgments" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 641, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 545, + 714 + ], + "type": "text", + "content": "This work was supported in part by NSF under Grants 2019511, 2146447, and in part by the BoRSF under Grants LEQSF(2019-22)-RD-A-21 and LEQSF(2021-22)-RD-D-07. Any opinion and findings expressed in the paper are those of the authors and do not necessarily reflect the view of funding agencies." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5782" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "type": "text", + "content": "[1] Faezeh Akhavizadegan, Javad Ansarifar, Lizhi Wang, Isaiah Huber, and Sotirios V Archontoulis. A time-dependent parameter estimation framework for crop modeling. Scientific reports, 2021." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 137, + 286, + 169 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 137, + 286, + 169 + ], + "spans": [ + { + "bbox": [ + 53, + 137, + 286, + 169 + ], + "type": "text", + "content": "[2] Javad Ansarifar, Lizhi Wang, and Sotirios V Archontoulis. An interaction regression model for crop yield prediction. Scientific reports, 2021." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 171, + 287, + 215 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 171, + 287, + 215 + ], + "spans": [ + { + "bbox": [ + 53, + 171, + 287, + 215 + ], + "type": "text", + "content": "[3] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In International Conference on Computer Vision (ICCV), 2021." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 217, + 287, + 248 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 217, + 287, + 248 + ], + "spans": [ + { + "bbox": [ + 53, + 217, + 287, + 248 + ], + "type": "text", + "content": "[4] Jimmy Lei Ba, Jamie Ryan Kiros, and Geoffrey E Hinton. Layer normalization. arXiv preprint arXiv:1607.06450, 2016." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 251, + 287, + 283 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 251, + 287, + 283 + ], + "spans": [ + { + "bbox": [ + 53, + 251, + 287, + 283 + ], + "type": "text", + "content": "[5] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. Beit: BERT pre-training of image transformers. In International Conference on Learning Representations (ICLR), 2022." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 285, + 287, + 340 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 285, + 287, + 340 + ], + "spans": [ + { + "bbox": [ + 53, + 285, + 287, + 340 + ], + "type": "text", + "content": "[6] Hangbo Bao, Li Dong, Furu Wei, Wenhui Wang, Nan Yang, Xiaodong Liu, Yu Wang, Jianfeng Gao, Songhao Piao, Ming Zhou, and Hsiao-Wuen Hon. Unilmv2: Pseudo-masked language models for unified language model pre-training. In International Conference on Machine Learning (ICML), 2020." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 342, + 286, + 385 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 342, + 286, + 385 + ], + "spans": [ + { + "bbox": [ + 53, + 342, + 286, + 385 + ], + "type": "text", + "content": "[7] Mathilde Caron, Hugo Touvron, Ishan Misra, Hervé Jégou, Julien Mairal, Piotr Bojanowski, and Armand Joulin. Emerging properties in self-supervised vision transformers. In International Conference on Computer Vision (ICCV), 2021." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 388, + 287, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 388, + 287, + 430 + ], + "spans": [ + { + "bbox": [ + 53, + 388, + 287, + 430 + ], + "type": "text", + "content": "[8] Liyan Chen, Weihan Wang, and Philippos Mordohai. Learning the distribution of errors in stereo matching for joint disparity and uncertainty estimation. In Computer Vision and Pattern Recognition (CVPR), 2023." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 433, + 287, + 476 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 433, + 287, + 476 + ], + "spans": [ + { + "bbox": [ + 53, + 433, + 287, + 476 + ], + "type": "text", + "content": "[9] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey E. Hinton. A simple framework for contrastive learning of visual representations. In International Conference on Machine Learning (ICML), 2020." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 478, + 287, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 478, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 48, + 478, + 287, + 533 + ], + "type": "text", + "content": "[10] Minghan Cheng, Xiyun Jiao, Lei Shi, Josep Penuelas, Lalit Kumar, Chenwei Nie, Tianao Wu, Kaihua Liu, Wenbin Wu, and Xiuliang Jin. High-resolution crop yield and water productivity dataset generated using random forest and remote sensing. Scientific Data, 2022." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 535, + 287, + 578 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 535, + 287, + 578 + ], + "spans": [ + { + "bbox": [ + 48, + 535, + 287, + 578 + ], + "type": "text", + "content": "[11] Karine Chenu, John Roy Porter, Pierre Martre, Bruno Basso, Scott Cameron Chapman, Frank Ewert, Marco Bindi, and Senthold Asseng. Contribution of crop models to adaptation in wheat. Trends in plant science, 2017." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 580, + 287, + 656 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 580, + 287, + 656 + ], + "spans": [ + { + "bbox": [ + 48, + 580, + 287, + 656 + ], + "type": "text", + "content": "[12] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations (ICLR), 2021." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 658, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 658, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 658, + 287, + 713 + ], + "type": "text", + "content": "[13] Nicola Falco, Haruko M Wainwright, Baptiste Dafflon, Craig Ulrich, Florian Soom, John E Peterson, James Bentley Brown, Karl B Schaettle, Malcolm Williamson, Jackson D Cothren, et al. Influence of soil heterogeneity on soybean plant development and crop yield evaluated using time-series" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 33, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "text", + "content": "of uav and ground-based geophysical imagery. Scientific reports, 2021." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 96, + 545, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 96, + 545, + 139 + ], + "spans": [ + { + "bbox": [ + 308, + 96, + 545, + 139 + ], + "type": "text", + "content": "[14] Haoqi Fan, Bo Xiong, Karttikeya Mangalam, Yanghao Li, Zhicheng Yan, Jitendra Malik, and Christoph Feichtenhofer. Multiscale vision transformers. In International Conference on Computer Vision (ICCV), 2021." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 141, + 545, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 141, + 545, + 184 + ], + "spans": [ + { + "bbox": [ + 308, + 141, + 545, + 184 + ], + "type": "text", + "content": "[15] Joshua Fan, Junwen Bai, Zhiyun Li, Ariel Ortiz-Bobea, and Carla P. Gomes. A GNN-RNN approach for harnessing geospatial and temporal information: Application to crop yield prediction. In AAAI, 2022." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 186, + 545, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 186, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 308, + 186, + 545, + 228 + ], + "type": "text", + "content": "[16] Niketa Gandhi, Owaiz Petkar, and Leisa J Armstrong. Rice crop yield prediction using artificial neural networks. In 2016 IEEE Technological Innovations in ICT for Agriculture and Rural Development (TIAR), 2016." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 230, + 545, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 230, + 545, + 274 + ], + "spans": [ + { + "bbox": [ + 308, + 230, + 545, + 274 + ], + "type": "text", + "content": "[17] Vivien Sainte Fare Garnot and Loic Landrieu. Panoptic segmentation of satellite image time series with convolutional temporal attention networks. In International Conference on Computer Vision (ICCV), 2021." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 275, + 545, + 318 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 275, + 545, + 318 + ], + "spans": [ + { + "bbox": [ + 308, + 275, + 545, + 318 + ], + "type": "text", + "content": "[18] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross B. Girshick. Masked autoencoders are scalable vision learners. In Conference on Computer Vision and Pattern Recognition (CVPR), 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 319, + 545, + 352 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 319, + 545, + 352 + ], + "spans": [ + { + "bbox": [ + 308, + 319, + 545, + 352 + ], + "type": "text", + "content": "[19] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Conference on Computer Vision and Pattern Recognition (CVPR), 2016." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 354, + 545, + 385 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 354, + 545, + 385 + ], + "spans": [ + { + "bbox": [ + 308, + 354, + 545, + 385 + ], + "type": "text", + "content": "[20] Yi He, Fudong Lin, Xu Yuan, and Nian-Feng Tzeng. Interpretable minority synthesis for imbalanced classification. In IJCAI, 2021." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 388, + 545, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 388, + 545, + 430 + ], + "spans": [ + { + "bbox": [ + 308, + 388, + 545, + 430 + ], + "type": "text", + "content": "[21] Byeongho Heo, Sangdoo Yun, Dongyoon Han, Sanghyuk Chun, Junsuk Choe, and Seong Joon Oh. Rethinking spatial dimensions of vision transformers. In International Conference on Computer Vision (ICCV), 2021." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 432, + 545, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 432, + 545, + 453 + ], + "spans": [ + { + "bbox": [ + 308, + 432, + 545, + 453 + ], + "type": "text", + "content": "[22] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 1997." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 455, + 544, + 476 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 455, + 544, + 476 + ], + "spans": [ + { + "bbox": [ + 308, + 455, + 544, + 476 + ], + "type": "text", + "content": "[23] Takeshi Horie, Masaharu Yajima, and Hiroshi Nakagawa. Yield forecasting. Agricultural systems, 1992." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 478, + 523, + 488 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 478, + 523, + 488 + ], + "spans": [ + { + "bbox": [ + 308, + 478, + 523, + 488 + ], + "type": "text", + "content": "[24] HRRR. The high-resolution rapid refresh (hrrr), 2022." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 490, + 545, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 490, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 308, + 490, + 545, + 555 + ], + "type": "text", + "content": "[25] James W Jones, John M Antle, Bruno Basso, Kenneth J Boote, Richard T Conant, Ian Foster, H Charles J Godfray, Mario Herrero, Richard E Howitt, Sander Janssen, et al. Toward a new generation of agricultural system data, models, and knowledge products: State of agricultural systems science. Agricultural systems, 2017." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 556, + 545, + 589 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 556, + 545, + 589 + ], + "spans": [ + { + "bbox": [ + 308, + 556, + 545, + 589 + ], + "type": "text", + "content": "[26] Saeed Khaki, Hieu Pham, and Lizhi Wang. Simultaneous corn and soybean yield prediction from remote sensing data using deep transfer learning. Scientific Reports, 2021." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 590, + 545, + 612 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 590, + 545, + 612 + ], + "spans": [ + { + "bbox": [ + 308, + 590, + 545, + 612 + ], + "type": "text", + "content": "[27] Saeed Khaki and Lizhi Wang. Crop yield prediction using deep neural networks. Frontiers in plant science, 2019." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 308, + 613, + 545, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 613, + 545, + 644 + ], + "spans": [ + { + "bbox": [ + 308, + 613, + 545, + 644 + ], + "type": "text", + "content": "[28] Saeed Khaki, Lizhi Wang, and Sotirios V Archontoulis. A cnn-rnn framework for crop yield prediction. Frontiers in Plant Science, 2020." + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 308, + 647, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 647, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 647, + 545, + 689 + ], + "type": "text", + "content": "[29] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E. Hinton. Imagenet classification with deep convolutional neural networks. In Neural Information Processing Systems (NeurIPS), 2012." + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "text", + "content": "[30] Zhengfeng Lai, Sol Vesdapunt, Ning Zhou, Jun Wu, Cong Phuoc Huynh, Xuelu Li, Kah Kuen Fu, and Chen-Nee" + } + ] + } + ], + "index": 32 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "5783" + } + ] + } + ], + "index": 34 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "type": "text", + "content": "Chuah. Padclip: Pseudo-labeling with adaptive debiasing in clip for unsupervised domain adaptation. In International Conference on Computer Vision (ICCV), 2023." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 287, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 287, + 162 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 287, + 162 + ], + "type": "text", + "content": "[31] Yanghao Li, Chao-Yuan Wu, Haoqi Fan, Karttikeya Mangalam, Bo Xiong, Jitendra Malik, and Christoph Feichtenhofer. Mvitv2: Improved multiscale vision transformers for classification and detection. In Computer Vision and Pattern Recognition (CVPR), 2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 163, + 287, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 163, + 287, + 206 + ], + "spans": [ + { + "bbox": [ + 48, + 163, + 287, + 206 + ], + "type": "text", + "content": "[32] Fudong Lin, Xu Yuan, Lu Peng, and Nian-Feng Tzeng. Cascade variational auto-encoder for hierarchical disentangle-. ment. In Conference on Information & Knowledge Management (CIKM), 2022." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 209, + 287, + 252 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 209, + 287, + 252 + ], + "spans": [ + { + "bbox": [ + 48, + 209, + 287, + 252 + ], + "type": "text", + "content": "[33] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In International Conference on Computer Vision (ICCV), 2021." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 254, + 287, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 254, + 287, + 285 + ], + "spans": [ + { + "bbox": [ + 48, + 254, + 287, + 285 + ], + "type": "text", + "content": "[34] Ilya Loshchilov and Frank Hutter. SGDR: stochastic gradient descent with warm restarts. In International Conference on Learning Representations (ICLR), 2017." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 287, + 287, + 319 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 287, + 287, + 319 + ], + "spans": [ + { + "bbox": [ + 48, + 287, + 287, + 319 + ], + "type": "text", + "content": "[35] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In International Conference on Learning Representations, 2019." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 321, + 287, + 354 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 321, + 287, + 354 + ], + "spans": [ + { + "bbox": [ + 48, + 321, + 287, + 354 + ], + "type": "text", + "content": "[36] Spyridon Mourtzinis, Paul D Esker, James E Specht, and Shawn P Conley. Advancing agricultural research using machine learning algorithms. Scientific reports, 2021." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 355, + 287, + 420 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 355, + 287, + 420 + ], + "spans": [ + { + "bbox": [ + 48, + 355, + 287, + 420 + ], + "type": "text", + "content": "[37] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, Gretchen Krueger, and Ilya Sutskever. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning (ICML), 2021." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 422, + 287, + 475 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 422, + 287, + 475 + ], + "spans": [ + { + "bbox": [ + 48, + 422, + 287, + 475 + ], + "type": "text", + "content": "[38] Colin Raffel, Noam Shazeer, Adam Roberts, Katherine Lee, Sharan Narang, Michael Matena, Yanqi Zhou, Wei Li, and Peter J Liu. Exploring the limits of transfer learning with a unified text-to-text transformer. The Journal of Machine Learning Research, 2020." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 478, + 287, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 478, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 48, + 478, + 287, + 533 + ], + "type": "text", + "content": "[39] David Rolnick, Priya L Donti, Lynn H Kaack, Kelly Kochanski, Alexandre Lacoste, Kris Sankaran, Andrew Slavin Ross, Nikola Milojevic-Dupont, Natasha Jaques, Anna Waldman-Brown, et al. Tackling climate change with machine learning. ACM Computing Surveys (CSUR), 2022." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 534, + 287, + 578 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 534, + 287, + 578 + ], + "spans": [ + { + "bbox": [ + 48, + 534, + 287, + 578 + ], + "type": "text", + "content": "[40] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Conference on Computer Vision and Pattern Recognition (CVPR), 2022." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 579, + 235, + 589 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 579, + 235, + 589 + ], + "spans": [ + { + "bbox": [ + 48, + 579, + 235, + 589 + ], + "type": "text", + "content": "[41] Sentinel-Hub. Sentinel hub process api, 2022." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 590, + 287, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 590, + 287, + 634 + ], + "spans": [ + { + "bbox": [ + 48, + 590, + 287, + 634 + ], + "type": "text", + "content": "[42] Mohsen Shahhosseini, Guiping Hu, Isaiah Huber, and Sotirios V Archontoulis. Coupling machine learning and crop modeling improves crop yield prediction in the us corn belt. Scientific reports, 2021." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 635, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 635, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 635, + 287, + 689 + ], + "type": "text", + "content": "[43] Xingjian Shi, Zhourong Chen, Hao Wang, Dit-Yan Yeung, Wai-Kin Wong, and Wang-chun Woo. Convolutional LSTM network: A machine learning approach for precipitation nowcasting. In Neural Information Processing Systems (NeurIPS), 2015." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 692, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 692, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 692, + 287, + 713 + ], + "type": "text", + "content": "[44] Fulu Tao, Masayuki Yokozawa, and Zhao Zhang. Modelling the impacts of weather and climate variability on crop pro" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 708 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "type": "text", + "content": "ductivity over a large area: a new process-based model development, optimization, and uncertainties analysis. agricultural and forest meteorology, 2009." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "type": "text", + "content": "[45] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. VideoMAE: Masked autoencoders are data-efficient learners for self-supervised video pre-training. In Neural Information Processing Systems (NeurIPS), 2022." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 152, + 545, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 206 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 206 + ], + "type": "text", + "content": "[46] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Hervé Jégou. Training data-efficient image transformers & distillation through attention. In Marina Meila and Tong Zhang, editors, International Conference on Machine Learning (ICML), 2021." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 208, + 545, + 251 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 208, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 307, + 208, + 545, + 251 + ], + "type": "text", + "content": "[47] Gabriel Tseng, Ivan Zvonkov, Catherine Nakalembe, and Hannah Kerner. Cropharvest: a global satellite dataset for crop type classification. Neural Information Processing Systems (NeurIPS), 2021." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 252, + 545, + 306 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 252, + 545, + 306 + ], + "spans": [ + { + "bbox": [ + 307, + 252, + 545, + 306 + ], + "type": "text", + "content": "[48] Matteo Turchetta, Luca Corinzia, Scott Sussex, Amanda Burton, Juan Herrera, Ioannis N Athanasiadis, Joachim M Buhmann, and Andreas Krause. Learning long-term crop management strategies with cyclesgym. In Neural Information Processing Systems (NeurIPS), 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 308, + 545, + 327 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 308, + 545, + 327 + ], + "spans": [ + { + "bbox": [ + 307, + 308, + 545, + 327 + ], + "type": "text", + "content": "[49] USDA. The united states department of agriculture (usda), 2022." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 331, + 545, + 373 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 331, + 545, + 373 + ], + "spans": [ + { + "bbox": [ + 307, + 331, + 545, + 373 + ], + "type": "text", + "content": "[50] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Neural Information Processing Systems (NeurIPS), 2017." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 375, + 545, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 375, + 545, + 430 + ], + "spans": [ + { + "bbox": [ + 307, + 375, + 545, + 430 + ], + "type": "text", + "content": "[51] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In International Conference on Computer Vision (ICCV), pages 548-558, 2021." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 431, + 545, + 474 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 431, + 545, + 474 + ], + "spans": [ + { + "bbox": [ + 307, + 431, + 545, + 474 + ], + "type": "text", + "content": "[52] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. PVT v2: Improved baselines with pyramid vision transformer. Comput. Vis. Media, 2022." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 475, + 545, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 475, + 545, + 529 + ], + "spans": [ + { + "bbox": [ + 307, + 475, + 545, + 529 + ], + "type": "text", + "content": "[53] Xiaocui Wu, Xiangming Xiao, Jean Steiner, Zhengwei Yang, Yuanwei Qin, and Jie Wang. Spatiotemporal changes of winter wheat planted and harvested areas, photosynthesis and grain production in the contiguous united states from 2008-2018. Remote Sensing, 2021." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 531, + 545, + 597 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 531, + 545, + 597 + ], + "spans": [ + { + "bbox": [ + 307, + 531, + 545, + 597 + ], + "type": "text", + "content": "[54] Rongting Xu, Hanqin Tian, Shufen Pan, Stephen A Prior, Yucheng Feng, William D Batchelor, Jian Chen, and Jia Yang. Global ammonia emissions from synthetic nitrogen fertilizer applications in agricultural systems: Empirical and process-based estimates and uncertainty. *Global change biology*, 2019." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 597, + 545, + 651 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 597, + 545, + 651 + ], + "spans": [ + { + "bbox": [ + 307, + 597, + 545, + 651 + ], + "type": "text", + "content": "[55] Li Yuan, Yunpeng Chen, Tao Wang, Weihao Yu, Yujun Shi, Zihang Jiang, Francis E. H. Tay, Jiashi Feng, and Shuicheng Yan. Tokens-to-token vit: Training vision transformers from scratch onImagenet. In International Conference on Computer Vision (ICCV), 2021." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 653, + 545, + 708 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 653, + 545, + 708 + ], + "spans": [ + { + "bbox": [ + 307, + 653, + 545, + 708 + ], + "type": "text", + "content": "[56] Yihe Zhang, Xu Yuan, Sytske K. Kimball, Eric Rappin, Li Chen, Paul J. Darby III, Tom Johnsten, Lu Peng, Boisy Pitre, David Bourrie, and Nian-Feng Tzeng. Precise weather parameter predictions for target regions via neural networks. In ECML-PKDD. Applied Data Science Track, 2021." + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "5784" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MMVP_ Motion-Matrix-Based Video Prediction/2d057465-769a-4de5-aaaa-89b4c330116e_content_list.json b/2023/MMVP_ Motion-Matrix-Based Video Prediction/2d057465-769a-4de5-aaaa-89b4c330116e_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..c3fe104595f3f63d458e21ae033c50aaafb25a89 --- /dev/null +++ b/2023/MMVP_ Motion-Matrix-Based Video Prediction/2d057465-769a-4de5-aaaa-89b4c330116e_content_list.json @@ -0,0 +1,1516 @@ +[ + { + "type": "text", + "text": "MMVP: Motion-Matrix-based Video Prediction", + "text_level": 1, + "bbox": [ + 241, + 130, + 727, + 150 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Yiqi Zhong $^{1*}$ Luming Liang $^{2*}$ Ilya Zharkov $^{2}$ Ulrich Neumann $^{1*}$ $^{1}$ University of Southern California $^{2}$ Microsoft", + "bbox": [ + 210, + 178, + 763, + 215 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1{yiqizhon,uneumann}@usc.edu 2{lulian,zharkov}@microsoft.com", + "bbox": [ + 210, + 215, + 759, + 234 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 268, + 313, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "A central challenge of video prediction lies where the system has to reason the objects' future motions from image frames while simultaneously maintaining the consistency of their appearances across frames. This work introduces an end-to-end trainable two-stream video prediction framework, Motion-Matrix-based Video Prediction (MMVP), to tackle this challenge. Unlike previous methods that usually handle motion prediction and appearance maintenance within the same set of modules, MMVP decouples motion and appearance information by constructing appearance-agnostic motion matrices. The motion matrices represent the temporal similarity of each and every pair of feature patches in the input frames, and are the sole input of the motion prediction module in MMVP. This design improves video prediction in both accuracy and efficiency, and reduces the model size. Results of extensive experiments demonstrate that MMVP outperforms state-of-the-art systems on public data sets by non-negligible large margins ( $\\approx$ 1 db in PSNR, UCF Sports) in significantly smaller model sizes (84% the size or smaller). Please refer to this link for the official code and the datasets used in this paper.", + "bbox": [ + 75, + 300, + 473, + 618 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 646, + 209, + 662 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Video prediction aims at predicting future frames from limited past frames. It is a longstanding yet unsolved problem studied for decades [13, 3]. Advancing research in this area benefits various applications such as video compression [29, 53, 28], surveillance systems [57, 59, 7], and robotics [9, 16, 8]. The task can be essentially broken down into two sub-tasks: i) motion prediction and ii) frame synthesis. Each sub-task has its unique goal that cannot be simply accomplished by achieving the other one. For the sub-task of motion prediction, systems need to reason the future movements of objects/backgrounds by discovering the motion cues hidden in the past frames. Whereas for", + "bbox": [ + 75, + 671, + 470, + 853 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "the sub-task of frame synthesis, systems need to maintain appearance features and generate future frames that keep appearance consistency. These separated goals make video prediction inherently much more difficult than the individual task of normal motion prediction or content synthesis.", + "bbox": [ + 500, + 268, + 892, + 347 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/c745e68edda03c063b3ca4bf4e348a5632bef93014e68409d91f91f0e13dfdc7.jpg", + "image_caption": [ + "Figure 1: Performance comparison on UCF Sports with STIP [4] and SimVP [12]. The hard subset contains samples where SSIM between the last observed frame and the first future frame is smaller than 0.6, which indicates drastic motion patterns (data is from Tables 2 and 6)." + ], + "image_footnote": [], + "bbox": [ + 532, + 359, + 857, + 599 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Most existing works in video prediction are based on a single-stream pipeline that conducts motion prediction and appearance feature extraction for frame synthesis within the same set of modules. Their systems [47, 45, 46, 55, 5, 4] usually grow out of advanced network structures for sequential data analysis, such as recurrent neural networks (RNNs) [31] and transformers [42]. One shared characteristic of those methods is that they show excellent capabilities in capturing complex motion patterns but lower capabilities in appearance maintenance, yielding \"correct\" but not \"good\" synthesized frames. The reason behind this is that those methods usually contain complicated spatial-temporal feature extraction and state transition operations, which can cause unavoidable appearance information loss.", + "bbox": [ + 496, + 688, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Equal contributions.", + "bbox": [ + 93, + 862, + 212, + 875 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "†The work is done during Yiqi Zhong's internship at Microsoft.", + "bbox": [ + 96, + 875, + 429, + 887 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "$\\ddagger$ Corresponding authors.", + "bbox": [ + 96, + 887, + 225, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "4273", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/eafe28ca599c68dc3be11a323c3d5ba4d42dce837b24bae62f4cadb44370bb84.jpg", + "image_caption": [ + "Figure 2: MMVP is a two-stream video prediction framework. It decouples motion prediction and appearance maintenance, and it reunites motion and appearance features through feature composition operation." + ], + "image_footnote": [], + "bbox": [ + 114, + 85, + 885, + 258 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Researchers have proposed several solutions to mitigate appearance information loss; the most common approaches are introducing sophisticated appearance-aware state transition unit [5, 4, 54], or adding frequent feature shortcuts from previous frames [12, 46, 47, 45]. However, the former solution tends to build cumbersome models with a huge number of parameters; and for the latter solution, too much residual information from previous frames can cause a larger performance drop for hard cases such as videos with fast movements and/or moving cameras. Figure 1 shows the comparison between STIP [4] (an example of the former solution) and SimVP [12] (an example of the latter solution).", + "bbox": [ + 75, + 314, + 472, + 494 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To avoid running into possible trade-offs between motion and appearance in single-stream pipelines, a few works have explored two-stream pipelines [27, 2, 10, 43, 11], decoupling motion prediction and appearance maintenance. However, they either require auxiliary sub-networks such as optical flow estimator [27, 52] and key point detector [11] to generate motion representations, which complicates video prediction and reduces the generalizability of systems; or they do not provide an efficient solution to reunite the predicted motion and the appearance features [6, 43].", + "bbox": [ + 75, + 501, + 468, + 652 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "With these gaps in current research, we introduce a novel two-stream, end-to-end trainable framework for video prediction: Motion-Matrix-based Video Prediction (MMVP) (see Figure 2 for the framework overview). As the name indicates, MMVP uses motion matrices as the decoupled motion representation of video frames. The motion matrix is a 4D matrix representing the image feature patches of consecutive frames (see Figure 3 I). As motion matrices are the sole input of the matrix predictor (i.e., the motion prediction module in MMVP), MMVP specifies the hidden motion information and makes the matrix predictor only focus on motion-related information. For the reunion of motion and appearance features, MMVP gets inspiration from the image autoencoder. It first embeds the past frames individually through an image encoder. Then it composes the embedding of the future frames using the predicted motion", + "bbox": [ + 75, + 657, + 470, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "matrices output by the matrix predictor and the past frames' embeddings through matrix multiplication (see Figure 3 II). Then, an image decoder decodes the composed embeddings into the predicted future frames.", + "bbox": [ + 496, + 314, + 890, + 373 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The advantage of MMVP is three-fold: (i) MMVP decouples motion and appearance by constructing motion matrices, requiring no extra construction modules; (ii) unlike optical flow that describes the one-to-one relationship between pixels, motion matrices describe the many-to-many relationship between feature patches, and are more flexible and applicable for real-world data; (iii) MMVP reunites the appearance and motion prediction results through matrix multiplication, which is interpretable and of little information loss. The advantages make MMVP a much more compact model with significantly fewer parameters yet still matching SOTA methods in performance. We validate MMVP on three datasets, UCF Sports [36], KTH [38], and MovingMNIST [41]. Experiments show that MMVP matches or surpasses SOTA methods on all three datasets across metrics. Specifically, compared to STIP [4], MMVP uses $84\\%$ fewer parameters (18M vs. 2.8M) but achieves $38\\%$ better performance in the LPIPS metric (12.73 vs. 7.88) on the UCF Sports dataset (Table 4).", + "bbox": [ + 496, + 375, + 892, + 662 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Works", + "text_level": 1, + "bbox": [ + 500, + 676, + 650, + 694 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Good video prediction systems should not only accurately reason the future motions of the objects but also maintain their appearances and synthesize consistent future frames. As the video resolution has become increasingly higher today, researchers should additionally consider the scalability and efficiency of video prediction systems [33].", + "bbox": [ + 496, + 703, + 890, + 794 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Most video prediction works to date adopt a single-stream pipeline that grows out of advanced techniques in sequential data analysis. Those techniques usually contain sophisticated spatial-temporal feature extraction operations and state transitions, which result in appearance information loss. Thus, researchers tend to modify the techniques to let them attend more to appearance mainte", + "bbox": [ + 496, + 795, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "4274", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/3871523fb7da684852f58c769c660e4fbf40bdde955559bd806b9fefc38611de.jpg", + "image_caption": [ + "I. Appearance-agnostic Motion Matrix M", + "II. Future Composition", + "Figure 3: MMVP relies on the motion matrix $\\mathbf{M}$ . $\\mathbf{M}$ is an appearance-agnostic motion representation that measures the cosine similarity between the feature patches of two consecutive frames. Information of the past frames $\\{\\mathcal{X}_0,\\dots,\\mathcal{X}_T\\}$ can compose the future information $\\{\\widehat{\\mathcal{X}}_{T + 1},\\dots,\\widehat{\\mathcal{X}_{T^{\\prime}}}\\}$ through matrix multiplication $\\otimes$ with $\\mathbf{M}$ ." + ], + "image_footnote": [], + "bbox": [ + 122, + 111, + 467, + 215 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/525a8701d8f92d8a2bd93b2f6579f840546571e3ab82f27bcdea0a7ee7e13506.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 465, + 113, + 883, + 210 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "nance [47, 40, 45, 5, 4, 46, 18]. Based on ConvLSTM [40], PredRNN [47] propose a novel memory state transition method between the recurrent nodes to help the appearance features from observations be delivered to the final prediction. E3D-LSTM [46] integrated 3D convolution operations to help emphasize the short-term appearance. CrevNet [23] uses a conditionally reversible network to preserve the information from the past frames. More recently, the progress in temporal modeling made by transformer-based methods [42] has drawn more attention. The field starts to see works that use transformers in video prediction tasks [15, 50, 35]. These works have a better information aggregation capability and less appearance information loss, but they usually have a huge number of parameters and lack scalability to higher-resolution videos.", + "bbox": [ + 75, + 272, + 472, + 500 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Seeking an alternative solution to video prediction and overcoming the drawbacks of the aforementioned methods, a few works have also explored the potential of decoupling motion and appearance and building a two-stream pipeline. Using optical flow is an intuitive idea. Several previous works [27, 2, 52, 10] use built-in or off-the-shell systems to predict the optical flow from the past to future frames; they use the predicted optical flow to warp past frames into final results. The drawbacks of this line of work are two-fold: i) time-consuming, especially for the warping procedure of high-resolution video sequences; ii) more importantly, the one-to-one relationship defined by the optical flow may not be applicable for some cases such as when one pixel or superpixel moves half of the pixel size, or when one pixel has impacts on several pixels in the next frames. Besides optical flow, pose [43] and keypoint [11] are also used to represent the motion of the objects in the scene for video prediction. However, this approach requires extra pose or keypoint detectors to process videos. For videos with multiple objects, more complex motions, and higher resolution, the efficiency of these extra modules cannot be guaranteed. Alternatively, MCNet [6] uses the difference between frames to represent motion information. It does not require extra modules, but using concatenation to reunite motion and appearance features is inefficient.", + "bbox": [ + 75, + 503, + 472, + 881 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Compared to the small number of two-stream video pre", + "bbox": [ + 96, + 885, + 468, + 901 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "diction systems above, our MMVP has three advantages: i) its motion matrix is able to describe the many-to-many relationship of the pixels or super-pixels, which makes MMVP much more flexible and reasonable for real-world data; ii) MMVP does not require an extra module to produce motion representation; and iii) the reunion of motion and appearance features is more intuitive and interpretable than the approaches used in previous works. This paper will demonstrate how MMVP makes a more capable and compact video prediction framework.", + "bbox": [ + 496, + 272, + 893, + 425 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Motion-Matrix-based Video Prediction", + "text_level": 1, + "bbox": [ + 498, + 438, + 849, + 454 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Framework Overview", + "text_level": 1, + "bbox": [ + 500, + 463, + 705, + 478 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Given a video sequence $\\mathcal{I} = \\{I_t\\}_{t=1}^T$ , where $I_t$ denotes the $t$ th frame, usually in the RGB format, MMVP estimates the future $T'$ frames $\\widehat{I_{T+1}}$ to $\\widehat{I_{T+T'}}$ from $I_1$ to $I_T$ . In comparison to the known frame set $\\mathcal{I}$ , we denote the estimated frame set as $\\mathcal{I}' = \\{I_t'\\}_{t=T+1}^{T+T'}$ . The training of the framework is solely supervised by mean-squared error (MSE) loss. MMVP consists of three steps as follows:", + "bbox": [ + 496, + 484, + 890, + 595 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Step 1: Spatial feature extraction. We use an RRDBs [44] based network architecture to model an image encoding function $\\Omega$ , defined in eq. 1. This image encoder embeds each frame $I_{i}, i \\in \\{1,2,\\dots,T\\}$ in a down-sample hidden space separately and outputs their corresponding hidden features $f_{i}$ . In MMVP, besides the image encoder, we have an extra filter block that models a filtering function $\\Theta$ defined in eq. 2. It takes $f_{i}$ as the input and aims to generate $g_{i}$ . As the module name indicates, the filter block aims to filter out motion-irrelevant features of $f_{i}$ for motion matrix construction. We will introduce the details in Sec. 3.2.", + "bbox": [ + 496, + 595, + 892, + 760 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Step 2: Motion matrix construction and prediction. MMVP generates a set of motion matrices $\\{\\mathbf{M}_{i,i + 1}\\} ,i\\in$ $\\{1,2,\\dots,T - 1\\}$ for every two consecutive frames based on their feature pairs $\\{g_i,g_{i + 1}\\}$ . Then, a matrix predicting function $\\Phi$ defined in eq. 4 takes $\\{\\mathbf{M}_{i,i + 1}\\}$ as the input and predicts future matrices $\\{\\widehat{\\mathbf{M}_{T,T + j}}\\} ,j\\in \\{T,\\dots,T + T'\\}$ . Sec. 3.3 will elaborate on the definition and construction procedures of the motion matrices, and Sec. 3.4 will demonstrate the inner structure of the matrix predictor.", + "bbox": [ + 496, + 762, + 893, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "4275", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Step 3: Future composing and decoding. Using the output of steps 1 and 2, MMVP composes the unknown information for future frames. Then, a future decoding module takes the composed features as the input and outputs the final prediction. We will introduce the feature composition procedure in Sec. 3.5 and the future decoding module in Sec. 3.6.", + "bbox": [ + 76, + 90, + 472, + 196 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Spatial Feature Extraction", + "text_level": 1, + "bbox": [ + 76, + 205, + 316, + 222 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Spatial feature extraction involves two components of the MMVP framework: image encoder, and filter block.", + "bbox": [ + 76, + 229, + 470, + 258 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The image encoder $\\Omega$ in MMVP encodes every $I_{i}$ from the input data sequence to their corresponding features $f_{i}$ individually. The filter block $\\Theta$ subsequently processes $f_{i}$ and makes it ready for the construction of a motion matrix. Formally,", + "bbox": [ + 76, + 260, + 468, + 335 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nf _ {i} = \\Omega \\left(I _ {i}\\right), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 230, + 335, + 468, + 351 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\ng _ {i} = \\Theta (f _ {i}), \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 230, + 356, + 468, + 372 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $i \\in \\{1, 2, \\dots, T\\}$ . We use a convolutional network with residual in residual dense blocks (RRDBs) [44] to implement the image encoder, and we use a two-layer convolutional network to implement the filter block. See the detailed network architecture in Appendix.", + "bbox": [ + 76, + 378, + 468, + 455 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Next, the output features of the image encoder will take participate in the future feature composition, while the output of the filter block is only used for motion matrices construction. The existence of the filter block helps the model to filter out irrelevant features from the image encoder output and allows the construction of motion matrices to focus more on motion-related features. See Table 2 for the ablation study about the filter block.", + "bbox": [ + 75, + 455, + 468, + 575 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Motion Matrix Construction", + "text_level": 1, + "bbox": [ + 76, + 585, + 333, + 599 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Given the output of the filter block $g_{i} \\in \\mathbb{R}^{\\frac{H}{S} \\times \\frac{W}{S}}$ , $i \\in \\{1,2,\\dots,T\\}$ , we denote the feature patch at $(h,w)$ , $w \\in \\{0,1,2,\\frac{W}{S} - 1\\}$ , $h \\in \\{0,1,2,\\frac{H}{S} - 1\\}$ as $g_{i}^{h,w}$ , where $H$ and $W$ are the input images' height and width, and $S$ is the downsampling ratio to the original image; thus $\\frac{H}{S}$ and $\\frac{W}{S}$ are respectively the feature map's height and width.", + "bbox": [ + 76, + 606, + 468, + 700 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "For two consecutive frames' feature $\\{g_i, g_{i+1}\\}$ , we calculate the cosine similarity for each and every pair of feature patches to construct a 4D motion matrix $\\mathbf{M}_{i,i+1} \\in \\mathbb{R}^{\\frac{H}{S} \\times \\frac{W}{S} \\times \\frac{H}{S} \\times \\frac{W}{S}}$ . We denote the element of the matrix $\\mathbf{M}_{i,i+1}$ at $(h_i, w_i, h_{i+1}, w_{i+1})$ as $\\mathbf{M}_{i,i+1}^{h_i, w_i, h_{i+1}, w_{i+1}}$ , and let", + "bbox": [ + 76, + 700, + 468, + 781 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {M} _ {i, i + 1} ^ {h _ {i}, w _ {i}, h _ {i + 1}, w _ {i + 1}} = D _ {c} \\left(g _ {i} ^ {h _ {i}, w _ {i}}, g _ {i + 1} ^ {h _ {i + 1}, w _ {i + 1}}\\right). \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 125, + 801, + 468, + 824 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In the equation, $D_{c}$ is the cosine similarity, $g_{i}^{h_{i},w_{i}}$ is the feature patch of frame $i$ with the index of $(h_i,w_i)$ , and $g_{i + 1}^{h_{i + 1},w_{i + 1}}$ is the feature patch of frame $i + 1$ with the index of $(h_{i + 1},w_{i + 1})$ . With a feature patch at $(h_i,w_i)$ of $g_{i}$ as an", + "bbox": [ + 76, + 837, + 468, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "example, the matrix $\\mathbf{M}_{i,i + 1}^{h_i,w_i}\\in \\mathbb{R}^{H\\times W}$ can be regarded as a heatmap that reflects how much impact $g_{i}^{h_{i},w_{i}}$ has on $g_{i + 1}$ , or more intuitively, the motion tendency of $g_{i}^{h_{i},w_{i}}$ (see Figure 5 for illustration). It is similar to the definition of optical flow [17], which determines the movement of a pixel or superpixel. The difference between optical flow and motion matrix is that motion matrix does not strictly define a one-to-one relationship between the pixels or superpixels of the current frame and those of the next frame. It is a more practical assumption in the video prediction task that one current feature patch may influence several future feature patches.", + "bbox": [ + 496, + 89, + 890, + 263 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.4. Matrix Prediction", + "text_level": 1, + "bbox": [ + 500, + 273, + 673, + 287 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Given the motion matrices of the past $T$ frames $\\{\\mathbf{M}_{1,2},\\mathbf{M}_{2,3},\\dots,\\mathbf{M}_{T - 1,T}\\}$ , the matrix predictor $\\Psi$ predicts the future matrices $\\{\\mathbf{M}_{T,T + 1},\\mathbf{M}_{T,T + 2},\\dots,\\mathbf{M}_{T,T'}\\}$ . Instead of predicting the motion matrices between the consecutive frames, we predict the ones between the last observed frame $I_{T}$ and every future frame $I_{T + j},j\\in \\{1,2,\\dots,T'\\}$ , as", + "bbox": [ + 498, + 296, + 890, + 388 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\left\\{\\widehat {\\mathbf {M} _ {T , T + j} ^ {w , h}} \\right\\} = \\Psi \\left(\\left\\{\\mathbf {M} _ {i, i + 1} ^ {w, h} \\right\\}\\right), \\forall i \\in \\{1, 2, \\dots , T - 1 \\}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 514, + 412, + 890, + 436 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbf{M}_{i,i+1}^{w,h} \\in \\mathbb{R}^{H \\times W}$ , $w \\in \\{1,2,\\dots,\\frac{W}{S}\\}$ and $h \\in \\{1,2,\\dots,\\frac{H}{S}\\}$ . This design aims to reduce the accumulative error during feature composition and is validated by the long-term prediction setting shown in Table 3. Since for this work, we focus on testing the function and performance of the MMVP framework, we report the use of a simple $3D$ fully convolutional architecture to implement $\\Psi$ . Fellow researchers can choose to easily replace the implementation of $\\Psi$ with more advanced temporal modules if they wish to pursue better performances.", + "bbox": [ + 496, + 448, + 892, + 604 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/da450c0279acec735040303e38e74079bf62a9f0b9190bdd1a3335f3cc4741c6.jpg", + "image_caption": [ + "Figure 4: All scales of image features and the original frames can join the future composition with predicted motion matrices through pixel unshuffle and shuffle operations." + ], + "image_footnote": [], + "bbox": [ + 501, + 618, + 893, + 825 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "4276", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.5. Multi-scale Future Composition", + "text_level": 1, + "bbox": [ + 76, + 90, + 359, + 107 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The future composition step generates information for the future frames using the observed information and the motion matrices. It is formulated as", + "bbox": [ + 76, + 114, + 468, + 159 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\widehat {\\mathcal {X} _ {T + j}} = \\sum_ {i = 1} ^ {T} \\left(\\mathcal {X} _ {i} \\times \\prod_ {n = i} ^ {T - 1} \\mathbf {M} _ {n, n + 1} \\times \\widehat {\\mathbf {M} _ {T , T + j}}\\right). \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 119, + 169, + 468, + 210 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "As the equation indicates, instead of only using the information of the last observed frame, we use all observed information for future composition and lower the weight of earlier frames through repeated multiplication of the motion matrices. The $\\mathcal{X}$ in the equation represents the observed information of the past frames. The information can be the output features of the image encoder with different scales $f_{i} \\in \\mathbb{R}^{H^{s} \\times W^{s} \\times C}$ , where $C$ is the feature length; the information can also be the observed frames $I_{i} \\in \\mathbb{R}^{H \\times W \\times 3}$ . Since the motion matrices are constructed from a certain scale of image features, there will be incompatibilities between the matrices and some features. To enable matrix multiplication between the motion matrices and the observed features (at any scales) or images, we borrow the pixel unshuffle and shuffle operations from [39]. The pixel unshuffle operation reshapes features or images into the identical scale as the motion matrices for matrix multiplication. Afterward, the pixel shuffle operation reshapes the results of the matrix multiplication back to the original scales of the features or images. See Figure 4 for demonstration. This whole process involves little information loss. In Table 6, we examine the multi-scale feature composition design. We find out that in general, the system achieves better performance when more scales of features take part in the feature composition.", + "bbox": [ + 76, + 219, + 470, + 597 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.6. Future Decoding", + "text_level": 1, + "bbox": [ + 76, + 608, + 243, + 625 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The future decoding procedure is used for aggregating and processing the composed features to formulate the final output. Since in the feature composition procedure, all scales of features are able to compose their corresponding scales of features for future frames, we adopt the decoder structure of UNet [37] with RRDB blocks [44] in the end to implement MMVP's image decoder. This design allows the composed features from all scales of image features, as well as the original images, to contribute to the final output. We use MSE loss to supervise the framework training.", + "bbox": [ + 75, + 632, + 468, + 784 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiment", + "text_level": 1, + "bbox": [ + 76, + 799, + 202, + 816 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In this section, we evaluate MMVP quantitatively and qualitatively against existing state-of-the-art methods on various publicly available datasets. In addition, we analyze MMVP through a set of ablation studies on the UCF Sports dataset to better illustrate our design logic.", + "bbox": [ + 75, + 824, + 470, + 902 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Datasets", + "text_level": 1, + "bbox": [ + 500, + 90, + 602, + 104 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We briefly review three widely used datasets and their configurations for MMVP evaluation.", + "bbox": [ + 498, + 114, + 893, + 145 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/6754e9d9f6abeeb2db0ea1005dea3dbf95259111b4e2cd219f96bf0302b2aecc.jpg", + "table_caption": [ + "Table 1: Experiment settings for each dataset." + ], + "table_footnote": [], + "table_body": "
DatasetResolutionTrainTest
UCF Sports512 × 5124 → 14 → 6
KTH128 × 12810 → 20 or 4010 → 20 or 40
Moving MNIST64 × 6410 → 1010 → 10
", + "bbox": [ + 514, + 172, + 877, + 234 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "UCF Sports [36] contains 150 video sequences collected from various sports scenes with 10 different action types including running, kicking, and diving. It is regarded as a challenging dataset given its low frame rate (10 fps), high resolution $(480 \\times 720)$ , and complex motion patterns. The video sequences in this dataset contain both rapid foreground (e.g. athletes) and background movements (e.g. the camera motion). We perform two different training/validation splits of this dataset, splits from STRPM [5] and our own splits, to facilitate different evaluation purposes. We use the STRPM splits for performance comparison with other methods (Table 4). In STRPM, long video sequences are cut into several short clips; for a particular sequence, some of its clips may be put into the training split, and others into the validation split. To avoid the appearance features of certain sequences in the validation set to be exposed in the training set, and to thoroughly evaluate MMVP's capability of video prediction, we generate our own splits for UCF Sports, which choose $90\\%$ of the video sequences from each action type to form the training samples, and the rest $10\\%$ to form the validation samples.", + "bbox": [ + 496, + 247, + 890, + 565 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Notably, within the same validation set, the difficulty level of different samples varies a lot. Some easier video clips contain static backgrounds and slow-moving objects, while others are more difficult for involving drastic camera movement and/or fast-moving objects. To better understand the model's prediction ability in different scenarios, we apply certain thresholds of the structural similarity index measure (SSIM) between the last observed frame and the first future frame to divide the UCF Sports validation set into three subsets: the easy $(\\mathrm{SSIM} \\leq 0.9)$ , intermediate $(0.6 \\leq \\mathrm{SSIM} < 0.9)$ , and hard subsets $(\\mathrm{SSIM} < 0.6)$ , which respectively take up $66\\%$ , $26\\%$ , and $8\\%$ of the full set.", + "bbox": [ + 496, + 566, + 890, + 747 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We use our own UCF Sports splits in the ablation studies (Sec. 4.3). For comparisons, we also train and test STIP [4] (extension of STRPM [5]) and SimVP [12] on our own UCF Sports splits; see Table 6.", + "bbox": [ + 498, + 748, + 893, + 808 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "KTH [38] contains videos of 25 individuals performing six types of actions, i.e., walking, jogging, running, boxing, hand-waving, and hand-clapping. Following previous works [43, 46, 12], we use persons 1-16 for training and persons 17-25 for validation. The videos in KTH are in grayscale, but the challenging part of this dataset is its ex", + "bbox": [ + 496, + 809, + 893, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "4277", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "periment setting, which requires the system to output 20 or 40 frames given only 10 past frames.", + "bbox": [ + 76, + 90, + 468, + 119 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Moving MNIST [41] is a synthetic dataset. Each sequence in the dataset consists of two digits moving independently within the $64 \\times 64$ grid and bouncing off the boundary. During the training time, by assigning different initial locations and velocities to each digit, one can generate an infinite number of sequences, and train the system to predict the future 10 frames from the previous 10 frames. For fair comparisons, we use the pre-generated 10000 sequences[12] for validation.", + "bbox": [ + 76, + 121, + 470, + 257 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Metrics", + "text_level": 1, + "bbox": [ + 76, + 268, + 171, + 282 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We use the peak signal-to-noise ratio (PSNR) and structural similarity index measure (SSIM) to evaluate the image quality of the predicted frames. We use the implementation of PSNR and SSIM from the package scikit-learn [34]. For the UCF Sports dataset, we use Learned Perceptual Image Patch Similarity (LPIPS) [58] for better comparison with existing methods. LPIPS represents the perceptual quality of the predicted frames. It measures the feature distance of corresponding image patches between the predicted frames and the ground truth. Following the setting of these previous works, in the experiments on Moving MNIST, we use the sum of the mean squared error (MSE) from the entire frame to evaluate the image quality.", + "bbox": [ + 75, + 291, + 470, + 488 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 500, + 230, + 513 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We conduct the ablation study of future composition (Table 6), filter block (3rd and 4th rows of Table 2), and hyperparameters for both the image encoder/decoder and the matrix predictor (1st, 2nd, and 4th rows of Table 2) on our splits of the UCF Sports dataset.", + "bbox": [ + 76, + 522, + 468, + 598 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We first examine how the number of feature scales for feature composition impacts the results. Since we use the UNet structure with three times downsampling/upsampling operations to encode, we have four different scales of features for composition. For UCF Sports, the scales are $1, \\frac{1}{2}, \\frac{1}{8}, \\frac{1}{16}$ . The motion matrices are constructed using features of $\\frac{1}{8}$ scale. From Table 6 3rd to 5th rows, we observe consistent performance boosts on all metrics and subsets when we involve more scales of features for composition. We then test if using images for feature composition also boosts performance. By comparing the 5th and 6th rows of Table 6, we can still see an increasing pattern. However, since the scale of the image is identical to the largest scale of the features, to avoid redundancy and possible conflicts, we remove the features of the largest scale and produce the results of the last row in Table 6. We then see a comparable result to the one that uses all scales of features as well as the image. We adopt the model setting of the last row for the rest of the experiments.", + "bbox": [ + 76, + 598, + 470, + 883 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "As mentioned in Sec. 3.2, we do not directly use the out", + "bbox": [ + 96, + 885, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "put of the image encoder to construct the motion matrices. Instead, we add a filter block to filter out irrelevant features and help the motion matrices focus more on describing the temporal similarity regarding the motion-related features. Table 2 shows that the model with the filter block generally achieves better results on the UCF Sports validation set.", + "bbox": [ + 496, + 90, + 890, + 181 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/009e55d3f09982a00309ed9cd74e2382d0b01e7dbf62522a241f4b0ea7efeeb0.jpg", + "table_caption": [ + "Table 2: Ablation study on UCF Sports with LPIPS metrics (the lower the better), including the feature length of image and motion, and the usage of the filter block (F-Block)." + ], + "table_footnote": [], + "table_body": "
ImgMotionF-BlockFullEasyIntermediateHardParam #
164✓0.11840.05920.18110.41680.70M
168✓0.11750.06000.17680.41220.71M
328×0.11240.05740.17290.38192.57M
328✓0.10620.05800.15690.35102.79M
STIPHR [4]0.16260.10660.22710.445018.05M
SimVP [12]0.13260.05840.19510.56003.47M
", + "bbox": [ + 509, + 252, + 875, + 340 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Furthermore, Table 2 also shows an ablation study on the feature length of the appearance-related modules (image encoder and decoder) and the motion-related module (matrix predictor). We define the configuration of the second row as the MMVP-mini for Figure 1.", + "bbox": [ + 496, + 347, + 890, + 422 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.4. Motion Matrix Visualization", + "text_level": 1, + "bbox": [ + 500, + 434, + 754, + 449 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In Figure 5, we visualize the predicted motion matrices for certain selected feature patches. In all the demonstrated samples, the many-to-many relationships described by the predicted motion matrices are able to accurately capture the feature patches moving tendency. They show that the motion matrix can describe a wide range of motion patterns and scenarios, including multiple objects (1st sample of UCF Sports), the single person moving (KTH), multiple persons moving and camera moving (2nd sample of UCF Sports), and synthesized motions (Moving MNIST).", + "bbox": [ + 496, + 457, + 890, + 609 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.5. Comparison with SOTA Methods", + "text_level": 1, + "bbox": [ + 498, + 619, + 792, + 635 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We compare MMVP with existing SOTA methods on three popular datasets: UCF Sports (STRPM [5] splits, Table 4), KTH (Table 3), and Moving MNIST (Table 5).", + "bbox": [ + 496, + 643, + 890, + 688 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "On the UCF Sports dataset, we observe large performance gains by MMVP compared to other methods. As mentioned above, the motion patterns in UCF Sports are the most complex of the three datasets due to many difficult cases, e.g., fast movement, camera moving, and motion blur. But the two-stream design of MMVP has shown its ability in such complex scenarios. Meanwhile, the video resolution of UCF Sports is also the highest among the three datasets. Most existing methods in Table 4 are inherently not designed for high-resolution videos, which requires larger network capacities to maintain appearance information. Although STRPM [5] and STIP [4] proposed residual temporal modules designed for high-resolution videos and they could largely surpass previous methods on both", + "bbox": [ + 496, + 689, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "4278", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/a667b0af9fb6c4ae95d91afbddb433ddaa4930524be4a12a5761ee817292b6a6.jpg", + "image_caption": [ + "Figure 5: Predicted motion matrix visualization. We highlight the selected feature patch(es) at $(h,w)$ in the last observed frame $I_{T}$ in red and visualize their corresponding predicted motion matrices $\\mathbf{M}_{T,T + 1}^{h,w}\\in \\mathbb{R}^{H\\times W}$ overlaying with the first future frame $I_{T + 1}$ . A brighter color indicates a higher predicted value. We select two samples for each dataset. From left to right, samples originate in the validation set of UCF Sports, KTH, and Moving MNIST." + ], + "image_footnote": [], + "bbox": [ + 147, + 85, + 836, + 318 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "metrics, the appearance information loss in their methods is still unavoidable. MMVP, nevertheless, allows the image and multi-scale features to reach the decoder through a feature composing procedure, successfully minimizes the information loss, and achieves the best performance among all methods across all metrics. MMVP's success on the UCF Sports dataset validates its readiness for real-world applications, and its scalability for high-resolution videos.", + "bbox": [ + 75, + 407, + 470, + 529 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Another notable result is MMVP's ability in long-term information preservation; see Table 3. Despite having lower video resolutions and less complex motion patterns than UCF Sports, KTH as a real-world dataset still presents a difficulty as it requires systems to do long-term prediction given short-term observations. On the KTH dataset, MMVP achieves the #1 performance on SSIM metrics for both experiment settings with a small performance gap (27.54 to 26.35) in PSNR between the two settings. This is contributed by the design that the matrix predictor of MMVP predicts the temporal similarity matrices between the future frames and the last observed frame instead of their predecessors. Then, every predicted frame is composed of valid observed information. It reduces accumulated errors and ensures good performance for long-term prediction.", + "bbox": [ + 75, + 534, + 468, + 761 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Compared to the performance gains on UCF Sports, MMVP does not show much advantage on the Moving MNIST dataset. One speculation is that with video prediction research advancing, the problem of two-digits Moving MNIST with low resolution $(64\\times 64)$ is nearly solved. With sufficient training time [12], current video prediction systems may all be able to achieve promising results. To further promote the growth of this field, researchers can consider more challenging datasets and experiment settings.", + "bbox": [ + 75, + 763, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/a63582f50e32287d00a04e5034897aab630594b9e255be2b09a32aa879779b04.jpg", + "table_caption": [ + "Table 3: Performance comparison on the KTH dataset" + ], + "table_footnote": [], + "table_body": "
MethodKTH10 → 20KTH10 → 40
SSIM ↑PSNR ↑SSIM ↑PSNR ↑
MCnet (ICLR2017) [43]0.80425.950.7323.89
ConvLSTM (NeurIPS2015) [40]0.71223.580.63922.85
SAVP (arXiv2018) [25]0.74625.380.70123.97
VPN (PMLR2017) [23]0.74623.76--
DFN (NeurIPS2016) [20]0.79427.260.65223.01
fRNN (ECCV2018) [32]0.77126.120.67823.77
Znet (ICME2019) [56]0.81727.58--
SV2Pi (ICLR2018) [1]0.82627.560.77825.92
SV2Pv (ICLR2018) [1]0.83827.790.78926.12
PredRNN (NeurIPS2017) [47]0.83927.550.70324.16
VarNet (IROS2018) [22]0.84328.480.73925.37
SVAP-VAE (arXiv2018) [25]0.85227.770.81126.18
PredRNN++ (ICML2018) [45]0.86528.470.74125.21
MSNET (BMVC2019) [26]0.87627.08--
E3d-LSTM (ICLR2019) [46]0.87929.310.81027.24
STMFANet (CVPR2020) [21]0.89329.850.85127.56
MMVP (ours)0.90627.540.88826.35
", + "bbox": [ + 501, + 425, + 888, + 664 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Moreover, we analyze MMVP's performance on data of different difficulty levels using our own split of the UCF Sports dataset. We define the difficulty of a video using the SSIM between the last observed frame and the first frame to be predicted. This is because a lower SSIM indicates a larger difference between the two frames, and less possibility for a system to take the shortcut by using the residual information from past frames and not actually predicting the motion. Table 6 shows the quantitative evaluation compared with SimVP [12] and STIP [4]: as the difficulty level of the validation subset increases, the performance gap between MMVP and other methods also increases.", + "bbox": [ + 496, + 686, + 892, + 867 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Besides quantitative evaluation, we also showcase several qualitative visualizations in Figure 6 and compare them", + "bbox": [ + 498, + 869, + 892, + 901 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "4279", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/9dce96e9a3b87470096ffbe40c7ea4195192d63185d3bba2c3c3bd637000870b.jpg", + "image_caption": [ + "Figure 6: Qualitative results on our own splits of the UCF Sports dataset." + ], + "image_footnote": [], + "bbox": [ + 116, + 90, + 851, + 351 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/a2f39eb6e48b3bfa7fff00f20fd02fbeaace96a3dccc48560ffd73917bbefe88.jpg", + "table_caption": [ + "Table 4: Performance comparison on UCF Sports STRPM split" + ], + "table_footnote": [], + "table_body": "
Methodt=5t=10
PSNR↑LPIPS×100↓PSNR↑LPIPS×100↓
ConvLSTM (NeurIPS2015) [40]26.4332.2017.8058.78
BeyondMSE (ICLR2016) [30]26.4229.0118.4655.28
PredRNN (NeurIPS2017) [47]27.1728.1519.6555.34
PredRNN++ (ICML2018) [45]27.2626.8019.6756.79
SAVP (arXiv2018) [25]27.3525.4519.9049.91
SV2P (ICLR2018) [1]27.4425.8919.9751.33
E3D-LSTM (ICLR2019) [46]27.9825.1320.3347.76
CycleGAN (CVPR2019) [24]27.9922.9519.9944.93
CrevNet (ICLR2020) [55]28.2323.8720.3348.15
MotionRNN (CVPR2021) [51]27.6724.2320.0149.20
STRPM (CVPR2022) [5]28.5420.6920.5941.11
STIP (arXiv2022) [4]30.7512.7321.8339.67
DMVFN (CVPR2023) [19]30.0510.2422.6722.50
MMVP (Ours)31.687.8823.2522.24
", + "bbox": [ + 78, + 398, + 524, + 602 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/8309b880bb61a6985dca065fc6091b0b6cb9f0fcadb08cf088c11de9b67de445.jpg", + "table_caption": [ + "Table 5: Comparisons on Moving MNIST" + ], + "table_footnote": [], + "table_body": "
MethodMSESSIM
ConvLSTM (NIPS 2015) [40]103.30.707
PredRNN (NIPS 2017) [47]56.80.867
PredRNN-V2 (Arxiv 2021) [48]48.40.891
CausalLSTM (ICML 2018) [45]46.50.898
MIM (CVPR 2019) [49]44.20.910
E3D-LSTM (ICLR 2018) [46]41.30.920
PhyDNet (CVPR 2020) [14]24.40.947
CrevNet (ICLR 2020) [55]22.30.949
SimVP (CVPR 2022) [12]23.80.948
MMVP(ours)22.20.952
", + "bbox": [ + 589, + 430, + 846, + 570 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/fd1c344bcae81d77946ab7ea8bfe5df1f0e036d4207e29b6025c174a4af35da4.jpg", + "table_caption": [ + "Table 6: Ablation study on sources for future composition and the comparison with other SOTA methods on UCF Sports." + ], + "table_footnote": [], + "table_body": "
MethodComposition sourceFull setEasy (SSIM ≥ 0.9)Intermediate (0.6 ≤ SSIM < 0.9)Hard (SSIM < 0.6)Param#
Img11/21/81/16SSIM ↑PSNR ↑LPIPS ↓SSIM ↑PSNR ↑LPIPS ↓SSIM ↑PSNR ↑LPIPS ↓SSIM ↑PSNR ↑LPIPS ↓
STIPHR [4]-0.881728.170.16260.949130.650.10660.835123.970.22710.467315.970.445018.05M
SimVP [12]-0.918929.970.13260.966432.870.05840.884525.790.19510.626718.990.56003.47M
MMVP×××✓✓0.900028.310.18740.937530.430.13420.875925.360.23040.659319.900.49922.75M
××✓✓✓0.928430.140.11150.966732.790.06030.893726.110.16930.715920.710.35702.79M
×✓✓✓✓0.929630.220.10640.966932.870.05760.896526.260.15710.719920.760.35552.80M
✓✓✓✓✓0.929630.290.10510.967532.990.05670.895826.220.15540.717520.760.35172.80M
✓×✓✓✓0.930030.350.10620.967433.050.05800.897026.290.15690.720320.840.35102.79M
", + "bbox": [ + 84, + 638, + 883, + 739 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "with SimVP [12] which achieved the second-best performance on our splits of the UCF Sports dataset. We especially select four samples in the hard and intermediate subsets for visualization. The first sample in Figure 6 shows a far-away object with long-distance movement. This is caused by the low fps of the dataset. MMVP accurately captures the displacement of the object while not losing the color and shape of the object. The challenge of the second sample in Figure 6 is also typical to UFC Sports,", + "bbox": [ + 75, + 760, + 470, + 896 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "i.e. fast movement with motion blur. MMVP is able to recover the correct shape of the athletes' feet even if they are blurred in the observed frames. The third and fourth samples both show a fast camera movement, with and without large foreground movements. Camera moving with complex backgrounds is extremely difficult for video prediction. Even SimVP, which generated high-quality images for most of the datasets, barely captured the camera movements in these two samples and caused drastic blurs. Benefiting from", + "bbox": [ + 496, + 760, + 890, + 896 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "4280", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "its appearance-agnostic motion prediction module, MMVP achieved impressive performance in such cases.", + "bbox": [ + 76, + 90, + 468, + 121 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Discussion", + "text_level": 1, + "bbox": [ + 76, + 137, + 191, + 152 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "From Table 2 and Table 6 in Sec. 4, we observe that the proposed MMVP framework can always achieve better or comparable performance with significantly fewer parameters compared to the other SOTA methods. To better understand the high efficiency of MMVP, we break down a video prediction system into three components: i) content encoder, which encodes the image sequences; ii) prediction-related modules, which take charge of predicting features for future frames based on the output of the content encoder; iii) content decoder, which decodes the output of the predicted features output by the prediction-related modules. Then we examine the model size for each component in three video prediction systems: STIP [4], SimVP [12], and the proposed MMVP (configurations follow the second row and the fourth row in Table 2); see Table 7.", + "bbox": [ + 75, + 162, + 472, + 388 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In Table 7, prediction-related modules in STIP [4] and SimVP [12] handle both motion and appearance features. However, in MMVP, prediction-related modules specifically handle only the motion features, leaving all appearance features to the content encoder and decoder. The most noticeable fact from Table 7 is that in STIP [4] and SimVP [12], the prediction-related modules take majority of the model parameters (the ratios are $99.7\\%$ and $99.4\\%$ respectively). In contrast, motion-related modules in MMVP only take $14.5\\%$ and $15.9\\%$ of the parameters. This fact supports our argument in Sec. 1 that decoupling motion prediction and appearance maintenance effectively avoid the cumbersome structures of the prediction modules and largely improve the prediction efficiency. Another observation is that despite the small size, the prediction-related modules in MMVP can still support high-quality motion prediction. This validates the efficiency of the motion matrices when describing the motion information, which results in a lightweight design of the prediction module.", + "bbox": [ + 75, + 388, + 472, + 679 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/45d1cf62ad8d13030c6f17e1e1edc73a4fd3b7c7502833a2ac673f854237656d.jpg", + "table_caption": [ + "Table 7: Model size breakdown. The numerical values are the number of parameters taken by each component in the video prediction systems." + ], + "table_footnote": [], + "table_body": "
MethodContent EncoderPrediction ModulesContent DecoderTotal
STIPHR [4]29.86K17994.8K29.54K18054.2K
SimVP [12]7.5k3447.1K11.7K3466.3K
MMVP-mini369.4K113.2K228.3K710.9K
MMVP1472.2K404.9K911.9K2789.0K
", + "bbox": [ + 78, + 750, + 467, + 810 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 844, + 196, + 859 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "The proposed Motion-Matrix-based Video Prediction framework (MMVP) is an end-to-end trainable two-stream", + "bbox": [ + 76, + 869, + 468, + 898 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "pipeline. MMVP uses motion matrices to represent appearance-agnostic motion patterns. As the sole input of the motion prediction module in MMVP, the motion matrix can i) describe the many-to-many relationships between feature patches without training for extra modules; ii) intuitively compose future features with multi-scale image features through matrix multiplication. It helps the motion prediction become more focused, and efficiently reduces the information loss in appearance. Extensive experiments demonstrate the superiority of MMVP compared to existing SOTA methods in both the model size and performance.", + "bbox": [ + 496, + 90, + 893, + 258 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 501, + 273, + 596, + 287 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Mohammad Babaeizadeh, Chelsea Finn, Dumitru Erhan, Roy H Campbell, and Sergey Levine. Stochastic variational video prediction. arXiv preprint arXiv:1710.11252, 2017. 7, 8", + "[2] Xinzhu Bei, Yanchao Yang, and Stefano Soatto. Learning semantic-aware dynamics for video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 902-912, 2021. 2, 3", + "[3] Po-Rong Chang and Jen-Tsung Hu. Optimal nonlinear adaptive prediction and modeling ofmpeg video in atm networks using pipelined recurrent neural networks. IEEE Journal on Selected Areas in Communications, 15(6):1087-1100, 1997. 1", + "[4] Zheng Chang, Xinfeng Zhang, Shanshe Wang, Siwei Ma, and Wen Gao. Stip: A spatiotemporal information-preserving and perception-augmented model for high-resolution video prediction. arXiv preprint arXiv:2206.04381, 2022. 1, 2, 3, 5, 6, 7, 8, 9", + "[5] Zheng Chang, Xinfeng Zhang, Shanshe Wang, Siwei Ma, and Wen Gao. Strpm: A spatiotemporal residual predictive model for high-resolution video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13946-13955, 2022. 1, 2, 3, 5, 6, 8", + "[6] Emily L Denton et al. Unsupervised learning of disentangled representations from video. Advances in neural information processing systems, 30, 2017. 2, 3", + "[7] Duarte Duque, Henrique Santos, and Paulo Cortez. Prediction of abnormal behaviors for intelligent video surveillance systems. In 2007 IEEE Symposium on Computational Intelligence and Data Mining, pages 362-367. IEEE, 2007. 1", + "[8] Frederik Ebert, Chelsea Finn, Sudeep Dasari, Annie Xie, Alex Lee, and Sergey Levine. Visual foresight: Model-based deep reinforcement learning for vision-based robotic control. arXiv preprint arXiv:1812.00568, 2018. 1", + "[9] Chelsea Finn and Sergey Levine. Deep visual foresight for planning robot motion. In 2017 IEEE International Conference on Robotics and Automation (ICRA), pages 2786-2793. IEEE, 2017. 1", + "[10] Hang Gao, Huazhe Xu, Qi-Zhi Cai, Ruth Wang, Fisher Yu, and Trevor Darrell. Disentangling propagation and generation for video prediction. In Proceedings of the IEEE/CVF" + ], + "bbox": [ + 501, + 297, + 893, + 901 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "4281", + "bbox": [ + 482, + 945, + 513, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "international conference on computer vision, pages 9006-9015, 2019. 2, 3", + "[11] Xiaojie Gao, Yueming Jin, Qi Dou, Chi-Wing Fu, and Pheng-Ann Heng. Accurate grid keypoint learning for efficient video prediction. In 2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages 5908–5915. IEEE, 2021. 2, 3", + "[12] Zhangyang Gao, Cheng Tan, Lirong Wu, and Stan Z Li. Simvp: Simpler yet better video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3170-3180, 2022. 1, 2, 5, 6, 7, 8, 9", + "[13] Bernd Girod. The efficiency of motion-compensating prediction for hybrid coding of video sequences. IEEE Journal on selected areas in communications, 5(7):1140-1154, 1987. 1", + "[14] Vincent Le Guen and Nicolas Thome. Disentangling physical dynamics from unknown factors for unsupervised video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11474-11484, 2020. 8", + "[15] Agrim Gupta, Stephen Tian, Yunzhi Zhang, Jiajun Wu, Roberto Martín-Martín, and Li Fei-Fei. Maskvit: Masked visual pre-training for video prediction. arXiv preprint arXiv:2206.11894, 2022.3", + "[16] Noriaki Hirose, Fei Xia, Roberto Martín-Martín, Amir Sadeghian, and Silvio Savarese. Deep visual mpc-policy learning for navigation. IEEE Robotics and Automation Letters, 4(4):3184-3191, 2019. 1", + "[17] Berthold KP Horn and Brian G Schunck. Determining optical flow. Artificial intelligence, 17(1-3):185–203, 1981. 4", + "[18] Jun-Ting Hsieh, Bingbin Liu, De-An Huang, Li F Fei-Fei, and Juan Carlos Niebles. Learning to decompose and disentangle representations for video prediction. Advances in neural information processing systems, 31, 2018. 3", + "[19] Xiaotao Hu, Zhewei Huang, Ailin Huang, Jun Xu, and Shuchang Zhou. A dynamic multi-scale voxel flow network for video prediction. arXiv preprint arXiv:2303.09875, 2023. 8", + "[20] Xu Jia, Bert De Brabandere, Tinne Tuytelaars, and Luc V Gool. Dynamic filter networks. Advances in neural information processing systems, 29, 2016. 7", + "[21] Beibei Jin, Yu Hu, Qiankun Tang, Jingyu Niu, Zhiping Shi, Yinhe Han, and Xiaowei Li. Exploring spatial-temporal multi-frequency analysis for high-fidelity and temporal-consistency video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4554-4563, 2020. 7", + "[22] Beibei Jin, Yu Hu, Yiming Zeng, Qiankun Tang, Shice Liu, and Jing Ye. Varnet: Exploring variations for unsupervised video prediction. In 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages 5801-5806. IEEE, 2018. 7", + "[23] Nal Kalchbrenner, Aäron Oord, Karen Simonyan, Ivo Danihelka, Oriol Vinyals, Alex Graves, and Koray Kavukcuoglu. Video pixel networks. In International Conference on Machine Learning, pages 1771-1779. PMLR, 2017. 3, 7", + "[24] Yong-Hoon Kwon and Min-Gyu Park. Predicting future frames using retrospective cycle gan. In Proceedings of" + ], + "bbox": [ + 78, + 92, + 468, + 901 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1811-1820, 2019. 8", + "[25] Alex X Lee, Richard Zhang, Frederik Ebert, Pieter Abbeel, Chelsea Finn, and Sergey Levine. Stochastic adversarial video prediction. arXiv preprint arXiv:1804.01523, 2018. 7, 8", + "[26] Jungbeom Lee, Jangho Lee, Sungmin Lee, and Sungroh Yoon. Mutual suppression network for video prediction using disentangled features. arXiv preprint arXiv:1804.04810, 2018. 7", + "[27] Xiaodan Liang, Lisa Lee, Wei Dai, and Eric P Xing. Dual motion gan for future-flow embedded video prediction. In proceedings of the IEEE international conference on computer vision, pages 1744-1752, 2017. 2, 3", + "[28] Jianping Lin, Dong Liu, Houqiang Li, and Feng Wu. M-lvc: Multiple frames prediction for learned video compression. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3546-3554, 2020. 1", + "[29] Bowen Liu, Yu Chen, Shiyu Liu, and Hun-Seok Kim. Deep learning in latent space for video prediction and compression. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 701-710, 2021. 1", + "[30] Michael Mathieu, Camille Couprie, and Yann LeCun. Deep multi-scale video prediction beyond mean square error. arXiv preprint arXiv:1511.05440, 2015. 8", + "[31] Tomas Mikolov, Martin Karafiát, Lukas Burget, Jan Cernocký, and Sanjeev Khudanpur. Recurrent neural network based language model. In *Interspeech*, volume 2, pages 1045–1048. Makuhari, 2010. 1", + "[32] Marc Oliu, Javier Selva, and Sergio Escalera. Folded recurrent neural networks for future video prediction. In Proceedings of the European Conference on Computer Vision (ECCV), pages 716-731, 2018. 7", + "[33] Sergiu Oprea, Pablo Martinez-Gonzalez, Alberto Garcia-Garcia, John Alejandro Castro-Vargas, Sergio Orts-Escalano, Jose Garcia-Rodriguez, and Antonis Argyros. A review on deep learning techniques for video prediction. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(6):2806-2826, 2020. 2", + "[34] F. Pedregosa, G. Varoquaux, A. Gramfort, V. Michel, B. Thirion, O. Grisel, M. Blondel, P. Prettenhofer, R. Weiss, V. Dubourg, J. Vanderplas, A. Passos, D. Cournaepau, M. Brucher, M. Perrot, and E. Duchesnay. Scikit-learn: Machine learning in Python. Journal of Machine Learning Research, 12:2825-2830, 2011. 6", + "[35] Ruslan Rakhimov, Denis Volkhonskiy, Alexey Artemov, Denis Zorin, and Evgeny Burnaev. Latent video transformer. arXiv preprint arXiv:2006.10704, 2020. 3", + "[36] Mikel D Rodriguez, Javed Ahmed, and Mubarak Shah. Action mach a spatio-temporal maximum average correlation height filter for action recognition. In 2008 IEEE conference on computer vision and pattern recognition, pages 1-8. IEEE, 2008. 2, 5", + "[37] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image com" + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "4282", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "puting and computer-assisted intervention, pages 234-241. Springer, 2015. 5", + "[38] Christian Schuldt, Ivan Laptev, and Barbara Caputo. Recognizing human actions: a localsvm approach. In Proceedings of the 17th International Conference on Pattern Recognition, 2004.ICPR 2004., volume 3,pages 32-36.IEEE,2004.2,5", + "[39] Wenzhe Shi, Jose Caballero, Ferenc Huszár, Johannes Totz, Andrew P Aitken, Rob Bishop, Daniel Rueckert, and Zehan Wang. Real-time single image and video super-resolution using an efficient sub-pixel convolutional neural network. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1874-1883, 2016. 5", + "[40] Xingjian Shi, Zhourong Chen, Hao Wang, Dit-Yan Yeung, Wai-Kin Wong, and Wang-chun Woo. Convolutional LSTM network: A machine learning approach for precipitation nowcasting. Advances in neural information processing systems, 28, 2015. 3, 7, 8", + "[41] Nitish Srivastava, Elman Mansimov, and Ruslan Salakhudinov. Unsupervised learning of video representations using lstms. In International conference on machine learning, pages 843-852. PMLR, 2015. 2, 6", + "[42] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. 1, 3", + "[43] Ruben Villegas, Jimei Yang, Seunghoon Hong, Xunyu Lin, and Honglak Lee. Decomposing motion and content for natural video sequence prediction. arXiv preprint arXiv:1706.08033, 2017. 2, 3, 5, 7", + "[44] Xintao Wang, Ke Yu, Shixiang Wu, Jinjin Gu, Yihao Liu, Chao Dong, Yu Qiao, and Chen Change Loy. Esrgan: Enhanced super-resolution generative adversarial networks. In Proceedings of the European conference on computer vision (ECCV) workshops, pages 0–0, 2018. 3, 4, 5", + "[45] Yunbo Wang, Zhifeng Gao, Mingsheng Long, Jianmin Wang, and S Yu Philip. Predrnn++: Towards a resolution of the deep-in-time dilemma in spatiotemporal predictive learning. In International Conference on Machine Learning, pages 5123-5132. PMLR, 2018. 1, 2, 3, 7, 8", + "[46] Yunbo Wang, Lu Jiang, Ming-Hsuan Yang, Li-Jia Li, Mingsheng Long, and Li Fei-Fei. Eidetic 3d LSTM: A model for video prediction and beyond. In International conference on learning representations, 2018. 1, 2, 3, 5, 7, 8", + "[47] Yunbo Wang, Mingsheng Long, Jianmin Wang, Zhifeng Gao, and Philip S Yu. Predrnn: Recurrent neural networks for predictive learning using spatiotemporal lstms. Advances in neural information processing systems, 30, 2017. 1, 2, 3, 7, 8", + "[48] Yunbo Wang, Haixu Wu, Jianjin Zhang, Zhifeng Gao, Jian-min Wang, Philip Yu, and Mingsheng Long. Predrnn: A recurrent neural network for spatiotemporal predictive learning. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 8", + "[49] Yunbo Wang, Jianjin Zhang, Hongyu Zhu, Mingsheng Long, Jianmin Wang, and Philip S Yu. Memory in memory: A predictive neural network for learning higher-order nonstationarity from spatiotemporal dynamics. In Proceedings" + ], + "bbox": [ + 78, + 90, + 470, + 900 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9154-9162, 2019. 8", + "[50] Dirk Weissenborn, Oscar Täckström, and Jakob Uszkoreit. Scaling autoregressive video models. arXiv preprint arXiv:1906.02634, 2019. 3", + "[51] Haixu Wu, Zhiyu Yao, Jianmin Wang, and Mingsheng Long. Motionrnn: A flexible model for video prediction with spacetime-varying motions. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 15435-15444, 2021. 8", + "[52] Yue Wu, Qiang Wen, and Qifeng Chen. Optimizing video prediction via video frame interpolation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 17814-17823, 2022. 2, 3", + "[53] Ren Yang, Radu Timofte, and Luc Van Gool. Advancing learned video compression with in-loop frame prediction. IEEE Transactions on Circuits and Systems for Video Technology, 2022. 1", + "[54] Wei Yu, Yichao Lu, Steve Easterbrook, and Sanja Fidler. Crevnet: Conditionally reversible video prediction. arXiv preprint arXiv:1910.11577, 2019. 2", + "[55] Wei Yu, Yichao Lu, Steve Easterbrook, and Sanja Fidler. Efficient and information-preserving future frame prediction and beyond. 2020. 1, 8", + "[56] Jianjin Zhang, Yunbo Wang, Mingsheng Long, Wang Jian-min, and S Yu Philip. Z-order recurrent neural networks for video prediction. In 2019 IEEE International Conference on Multimedia and Expo (ICME), pages 230-235. IEEE, 2019. 7", + "[57] Qianqian Zhang, Guorui Feng, and Hanzhou Wu. Surveillance video anomaly detection via non-local u-net frame prediction. Multimedia Tools and Applications, 81(19):27073-27088, 2022. 1", + "[58] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 586-595, 2018. 6", + "[59] Xianguo Zhang, Tiejun Huang, Yonghong Tian, and Wen Gao. Background-modeling-based adaptive prediction for surveillance video coding. IEEE Transactions on Image Processing, 23(2):769-784, 2013. 1" + ], + "bbox": [ + 501, + 92, + 893, + 685 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "4283", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MMVP_ Motion-Matrix-Based Video Prediction/2d057465-769a-4de5-aaaa-89b4c330116e_model.json b/2023/MMVP_ Motion-Matrix-Based Video Prediction/2d057465-769a-4de5-aaaa-89b4c330116e_model.json new file mode 100644 index 0000000000000000000000000000000000000000..11b1db4bb95cf6ca0cff30e1dc469097b8a96c18 --- /dev/null +++ b/2023/MMVP_ Motion-Matrix-Based Video Prediction/2d057465-769a-4de5-aaaa-89b4c330116e_model.json @@ -0,0 +1,2246 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.243, + 0.131, + 0.728, + 0.151 + ], + "angle": 0, + "content": "MMVP: Motion-Matrix-based Video Prediction" + }, + { + "type": "text", + "bbox": [ + 0.212, + 0.179, + 0.764, + 0.216 + ], + "angle": 0, + "content": "Yiqi Zhong\\(^{1*}\\) Luming Liang\\(^{2*}\\) Ilya Zharkov\\(^{2}\\) Ulrich Neumann\\(^{1*}\\) \n\\(^{1}\\)University of Southern California \\(^{2}\\)Microsoft" + }, + { + "type": "text", + "bbox": [ + 0.212, + 0.216, + 0.761, + 0.235 + ], + "angle": 0, + "content": "1{yiqizhon,uneumann}@usc.edu 2{lulian,zharkov}@microsoft.com" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.269, + 0.314, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.301, + 0.474, + 0.619 + ], + "angle": 0, + "content": "A central challenge of video prediction lies where the system has to reason the objects' future motions from image frames while simultaneously maintaining the consistency of their appearances across frames. This work introduces an end-to-end trainable two-stream video prediction framework, Motion-Matrix-based Video Prediction (MMVP), to tackle this challenge. Unlike previous methods that usually handle motion prediction and appearance maintenance within the same set of modules, MMVP decouples motion and appearance information by constructing appearance-agnostic motion matrices. The motion matrices represent the temporal similarity of each and every pair of feature patches in the input frames, and are the sole input of the motion prediction module in MMVP. This design improves video prediction in both accuracy and efficiency, and reduces the model size. Results of extensive experiments demonstrate that MMVP outperforms state-of-the-art systems on public data sets by non-negligible large margins (\\(\\approx\\) 1 db in PSNR, UCF Sports) in significantly smaller model sizes (84% the size or smaller). Please refer to this link for the official code and the datasets used in this paper." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.647, + 0.21, + 0.663 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.672, + 0.471, + 0.854 + ], + "angle": 0, + "content": "Video prediction aims at predicting future frames from limited past frames. It is a longstanding yet unsolved problem studied for decades [13, 3]. Advancing research in this area benefits various applications such as video compression [29, 53, 28], surveillance systems [57, 59, 7], and robotics [9, 16, 8]. The task can be essentially broken down into two sub-tasks: i) motion prediction and ii) frame synthesis. Each sub-task has its unique goal that cannot be simply accomplished by achieving the other one. For the sub-task of motion prediction, systems need to reason the future movements of objects/backgrounds by discovering the motion cues hidden in the past frames. Whereas for" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.27, + 0.893, + 0.348 + ], + "angle": 0, + "content": "the sub-task of frame synthesis, systems need to maintain appearance features and generate future frames that keep appearance consistency. These separated goals make video prediction inherently much more difficult than the individual task of normal motion prediction or content synthesis." + }, + { + "type": "image", + "bbox": [ + 0.534, + 0.36, + 0.859, + 0.6 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.604, + 0.895, + 0.682 + ], + "angle": 0, + "content": "Figure 1: Performance comparison on UCF Sports with STIP [4] and SimVP [12]. The hard subset contains samples where SSIM between the last observed frame and the first future frame is smaller than 0.6, which indicates drastic motion patterns (data is from Tables 2 and 6)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.689, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Most existing works in video prediction are based on a single-stream pipeline that conducts motion prediction and appearance feature extraction for frame synthesis within the same set of modules. Their systems [47, 45, 46, 55, 5, 4] usually grow out of advanced network structures for sequential data analysis, such as recurrent neural networks (RNNs) [31] and transformers [42]. One shared characteristic of those methods is that they show excellent capabilities in capturing complex motion patterns but lower capabilities in appearance maintenance, yielding \"correct\" but not \"good\" synthesized frames. The reason behind this is that those methods usually contain complicated spatial-temporal feature extraction and state transition operations, which can cause unavoidable appearance information loss." + }, + { + "type": "page_footnote", + "bbox": [ + 0.094, + 0.863, + 0.214, + 0.876 + ], + "angle": 0, + "content": "*Equal contributions." + }, + { + "type": "page_footnote", + "bbox": [ + 0.097, + 0.876, + 0.431, + 0.888 + ], + "angle": 0, + "content": "†The work is done during Yiqi Zhong's internship at Microsoft." + }, + { + "type": "page_footnote", + "bbox": [ + 0.097, + 0.888, + 0.227, + 0.9 + ], + "angle": 0, + "content": "\\(\\ddagger\\) Corresponding authors." + }, + { + "type": "list", + "bbox": [ + 0.094, + 0.863, + 0.431, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "4273" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.116, + 0.087, + 0.887, + 0.26 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.264, + 0.895, + 0.297 + ], + "angle": 0, + "content": "Figure 2: MMVP is a two-stream video prediction framework. It decouples motion prediction and appearance maintenance, and it reunites motion and appearance features through feature composition operation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.315, + 0.473, + 0.496 + ], + "angle": 0, + "content": "Researchers have proposed several solutions to mitigate appearance information loss; the most common approaches are introducing sophisticated appearance-aware state transition unit [5, 4, 54], or adding frequent feature shortcuts from previous frames [12, 46, 47, 45]. However, the former solution tends to build cumbersome models with a huge number of parameters; and for the latter solution, too much residual information from previous frames can cause a larger performance drop for hard cases such as videos with fast movements and/or moving cameras. Figure 1 shows the comparison between STIP [4] (an example of the former solution) and SimVP [12] (an example of the latter solution)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.502, + 0.47, + 0.653 + ], + "angle": 0, + "content": "To avoid running into possible trade-offs between motion and appearance in single-stream pipelines, a few works have explored two-stream pipelines [27, 2, 10, 43, 11], decoupling motion prediction and appearance maintenance. However, they either require auxiliary sub-networks such as optical flow estimator [27, 52] and key point detector [11] to generate motion representations, which complicates video prediction and reduces the generalizability of systems; or they do not provide an efficient solution to reunite the predicted motion and the appearance features [6, 43]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.659, + 0.471, + 0.902 + ], + "angle": 0, + "content": "With these gaps in current research, we introduce a novel two-stream, end-to-end trainable framework for video prediction: Motion-Matrix-based Video Prediction (MMVP) (see Figure 2 for the framework overview). As the name indicates, MMVP uses motion matrices as the decoupled motion representation of video frames. The motion matrix is a 4D matrix representing the image feature patches of consecutive frames (see Figure 3 I). As motion matrices are the sole input of the matrix predictor (i.e., the motion prediction module in MMVP), MMVP specifies the hidden motion information and makes the matrix predictor only focus on motion-related information. For the reunion of motion and appearance features, MMVP gets inspiration from the image autoencoder. It first embeds the past frames individually through an image encoder. Then it composes the embedding of the future frames using the predicted motion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.315, + 0.892, + 0.374 + ], + "angle": 0, + "content": "matrices output by the matrix predictor and the past frames' embeddings through matrix multiplication (see Figure 3 II). Then, an image decoder decodes the composed embeddings into the predicted future frames." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.376, + 0.893, + 0.663 + ], + "angle": 0, + "content": "The advantage of MMVP is three-fold: (i) MMVP decouples motion and appearance by constructing motion matrices, requiring no extra construction modules; (ii) unlike optical flow that describes the one-to-one relationship between pixels, motion matrices describe the many-to-many relationship between feature patches, and are more flexible and applicable for real-world data; (iii) MMVP reunites the appearance and motion prediction results through matrix multiplication, which is interpretable and of little information loss. The advantages make MMVP a much more compact model with significantly fewer parameters yet still matching SOTA methods in performance. We validate MMVP on three datasets, UCF Sports [36], KTH [38], and MovingMNIST [41]. Experiments show that MMVP matches or surpasses SOTA methods on all three datasets across metrics. Specifically, compared to STIP [4], MMVP uses \\(84\\%\\) fewer parameters (18M vs. 2.8M) but achieves \\(38\\%\\) better performance in the LPIPS metric (12.73 vs. 7.88) on the UCF Sports dataset (Table 4)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.678, + 0.651, + 0.695 + ], + "angle": 0, + "content": "2. Related Works" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.704, + 0.892, + 0.795 + ], + "angle": 0, + "content": "Good video prediction systems should not only accurately reason the future motions of the objects but also maintain their appearances and synthesize consistent future frames. As the video resolution has become increasingly higher today, researchers should additionally consider the scalability and efficiency of video prediction systems [33]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Most video prediction works to date adopt a single-stream pipeline that grows out of advanced techniques in sequential data analysis. Those techniques usually contain sophisticated spatial-temporal feature extraction operations and state transitions, which result in appearance information loss. Thus, researchers tend to modify the techniques to let them attend more to appearance mainte" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "4274" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.125, + 0.098, + 0.378, + 0.112 + ], + "angle": 0, + "content": "I. Appearance-agnostic Motion Matrix M" + }, + { + "type": "image", + "bbox": [ + 0.124, + 0.112, + 0.468, + 0.216 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.458, + 0.099, + 0.598, + 0.112 + ], + "angle": 0, + "content": "II. Future Composition" + }, + { + "type": "image", + "bbox": [ + 0.467, + 0.114, + 0.885, + 0.212 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.075, + 0.217, + 0.894, + 0.266 + ], + "angle": 0, + "content": "Figure 3: MMVP relies on the motion matrix \\(\\mathbf{M}\\). \\(\\mathbf{M}\\) is an appearance-agnostic motion representation that measures the cosine similarity between the feature patches of two consecutive frames. Information of the past frames \\(\\{\\mathcal{X}_0,\\dots,\\mathcal{X}_T\\}\\) can compose the future information \\(\\{\\widehat{\\mathcal{X}}_{T + 1},\\dots,\\widehat{\\mathcal{X}_{T^{\\prime}}}\\}\\) through matrix multiplication \\(\\otimes\\) with \\(\\mathbf{M}\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.273, + 0.473, + 0.501 + ], + "angle": 0, + "content": "nance [47, 40, 45, 5, 4, 46, 18]. Based on ConvLSTM [40], PredRNN [47] propose a novel memory state transition method between the recurrent nodes to help the appearance features from observations be delivered to the final prediction. E3D-LSTM [46] integrated 3D convolution operations to help emphasize the short-term appearance. CrevNet [23] uses a conditionally reversible network to preserve the information from the past frames. More recently, the progress in temporal modeling made by transformer-based methods [42] has drawn more attention. The field starts to see works that use transformers in video prediction tasks [15, 50, 35]. These works have a better information aggregation capability and less appearance information loss, but they usually have a huge number of parameters and lack scalability to higher-resolution videos." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.504, + 0.473, + 0.882 + ], + "angle": 0, + "content": "Seeking an alternative solution to video prediction and overcoming the drawbacks of the aforementioned methods, a few works have also explored the potential of decoupling motion and appearance and building a two-stream pipeline. Using optical flow is an intuitive idea. Several previous works [27, 2, 52, 10] use built-in or off-the-shell systems to predict the optical flow from the past to future frames; they use the predicted optical flow to warp past frames into final results. The drawbacks of this line of work are two-fold: i) time-consuming, especially for the warping procedure of high-resolution video sequences; ii) more importantly, the one-to-one relationship defined by the optical flow may not be applicable for some cases such as when one pixel or superpixel moves half of the pixel size, or when one pixel has impacts on several pixels in the next frames. Besides optical flow, pose [43] and keypoint [11] are also used to represent the motion of the objects in the scene for video prediction. However, this approach requires extra pose or keypoint detectors to process videos. For videos with multiple objects, more complex motions, and higher resolution, the efficiency of these extra modules cannot be guaranteed. Alternatively, MCNet [6] uses the difference between frames to represent motion information. It does not require extra modules, but using concatenation to reunite motion and appearance features is inefficient." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.886, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Compared to the small number of two-stream video pre" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.273, + 0.895, + 0.426 + ], + "angle": 0, + "content": "diction systems above, our MMVP has three advantages: i) its motion matrix is able to describe the many-to-many relationship of the pixels or super-pixels, which makes MMVP much more flexible and reasonable for real-world data; ii) MMVP does not require an extra module to produce motion representation; and iii) the reunion of motion and appearance features is more intuitive and interpretable than the approaches used in previous works. This paper will demonstrate how MMVP makes a more capable and compact video prediction framework." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.439, + 0.851, + 0.455 + ], + "angle": 0, + "content": "3. Motion-Matrix-based Video Prediction" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.464, + 0.706, + 0.479 + ], + "angle": 0, + "content": "3.1. Framework Overview" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.486, + 0.892, + 0.596 + ], + "angle": 0, + "content": "Given a video sequence \\(\\mathcal{I} = \\{I_t\\}_{t=1}^T\\), where \\(I_t\\) denotes the \\(t\\)th frame, usually in the RGB format, MMVP estimates the future \\(T'\\) frames \\(\\widehat{I_{T+1}}\\) to \\(\\widehat{I_{T+T'}}\\) from \\(I_1\\) to \\(I_T\\). In comparison to the known frame set \\(\\mathcal{I}\\), we denote the estimated frame set as \\(\\mathcal{I}' = \\{I_t'\\}_{t=T+1}^{T+T'}\\). The training of the framework is solely supervised by mean-squared error (MSE) loss. MMVP consists of three steps as follows:" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.596, + 0.893, + 0.761 + ], + "angle": 0, + "content": "Step 1: Spatial feature extraction. We use an RRDBs [44] based network architecture to model an image encoding function \\(\\Omega\\), defined in eq. 1. This image encoder embeds each frame \\(I_{i}, i \\in \\{1,2,\\dots,T\\}\\) in a down-sample hidden space separately and outputs their corresponding hidden features \\(f_{i}\\). In MMVP, besides the image encoder, we have an extra filter block that models a filtering function \\(\\Theta\\) defined in eq. 2. It takes \\(f_{i}\\) as the input and aims to generate \\(g_{i}\\). As the module name indicates, the filter block aims to filter out motion-irrelevant features of \\(f_{i}\\) for motion matrix construction. We will introduce the details in Sec. 3.2." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.763, + 0.895, + 0.902 + ], + "angle": 0, + "content": "Step 2: Motion matrix construction and prediction. MMVP generates a set of motion matrices \\(\\{\\mathbf{M}_{i,i + 1}\\} ,i\\in\\) \\(\\{1,2,\\dots,T - 1\\}\\) for every two consecutive frames based on their feature pairs \\(\\{g_i,g_{i + 1}\\}\\). Then, a matrix predicting function \\(\\Phi\\) defined in eq. 4 takes \\(\\{\\mathbf{M}_{i,i + 1}\\}\\) as the input and predicts future matrices \\(\\{\\widehat{\\mathbf{M}_{T,T + j}}\\} ,j\\in \\{T,\\dots,T + T'\\}\\). Sec. 3.3 will elaborate on the definition and construction procedures of the motion matrices, and Sec. 3.4 will demonstrate the inner structure of the matrix predictor." + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "4275" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.198 + ], + "angle": 0, + "content": "Step 3: Future composing and decoding. Using the output of steps 1 and 2, MMVP composes the unknown information for future frames. Then, a future decoding module takes the composed features as the input and outputs the final prediction. We will introduce the feature composition procedure in Sec. 3.5 and the future decoding module in Sec. 3.6." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.207, + 0.318, + 0.223 + ], + "angle": 0, + "content": "3.2. Spatial Feature Extraction" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.23, + 0.471, + 0.26 + ], + "angle": 0, + "content": "Spatial feature extraction involves two components of the MMVP framework: image encoder, and filter block." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.261, + 0.47, + 0.336 + ], + "angle": 0, + "content": "The image encoder \\(\\Omega\\) in MMVP encodes every \\(I_{i}\\) from the input data sequence to their corresponding features \\(f_{i}\\) individually. The filter block \\(\\Theta\\) subsequently processes \\(f_{i}\\) and makes it ready for the construction of a motion matrix. Formally," + }, + { + "type": "equation", + "bbox": [ + 0.232, + 0.336, + 0.469, + 0.352 + ], + "angle": 0, + "content": "\\[\nf _ {i} = \\Omega \\left(I _ {i}\\right), \\tag {1}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.232, + 0.357, + 0.469, + 0.373 + ], + "angle": 0, + "content": "\\[\ng _ {i} = \\Theta (f _ {i}), \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.38, + 0.469, + 0.456 + ], + "angle": 0, + "content": "where \\( i \\in \\{1, 2, \\dots, T\\} \\). We use a convolutional network with residual in residual dense blocks (RRDBs) [44] to implement the image encoder, and we use a two-layer convolutional network to implement the filter block. See the detailed network architecture in Appendix." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.456, + 0.469, + 0.576 + ], + "angle": 0, + "content": "Next, the output features of the image encoder will take participate in the future feature composition, while the output of the filter block is only used for motion matrices construction. The existence of the filter block helps the model to filter out irrelevant features from the image encoder output and allows the construction of motion matrices to focus more on motion-related features. See Table 2 for the ablation study about the filter block." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.587, + 0.334, + 0.601 + ], + "angle": 0, + "content": "3.3. Motion Matrix Construction" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.607, + 0.469, + 0.701 + ], + "angle": 0, + "content": "Given the output of the filter block \\( g_{i} \\in \\mathbb{R}^{\\frac{H}{S} \\times \\frac{W}{S}} \\), \\( i \\in \\{1,2,\\dots,T\\} \\), we denote the feature patch at \\( (h,w) \\), \\( w \\in \\{0,1,2,\\frac{W}{S} - 1\\} \\), \\( h \\in \\{0,1,2,\\frac{H}{S} - 1\\} \\) as \\( g_{i}^{h,w} \\), where \\( H \\) and \\( W \\) are the input images' height and width, and \\( S \\) is the downsampling ratio to the original image; thus \\( \\frac{H}{S} \\) and \\( \\frac{W}{S} \\) are respectively the feature map's height and width." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.702, + 0.469, + 0.782 + ], + "angle": 0, + "content": "For two consecutive frames' feature \\(\\{g_i, g_{i+1}\\}\\), we calculate the cosine similarity for each and every pair of feature patches to construct a 4D motion matrix \\(\\mathbf{M}_{i,i+1} \\in \\mathbb{R}^{\\frac{H}{S} \\times \\frac{W}{S} \\times \\frac{H}{S} \\times \\frac{W}{S}}\\). We denote the element of the matrix \\(\\mathbf{M}_{i,i+1}\\) at \\((h_i, w_i, h_{i+1}, w_{i+1})\\) as \\(\\mathbf{M}_{i,i+1}^{h_i, w_i, h_{i+1}, w_{i+1}}\\), and let" + }, + { + "type": "equation", + "bbox": [ + 0.127, + 0.803, + 0.469, + 0.825 + ], + "angle": 0, + "content": "\\[\n\\mathbf {M} _ {i, i + 1} ^ {h _ {i}, w _ {i}, h _ {i + 1}, w _ {i + 1}} = D _ {c} \\left(g _ {i} ^ {h _ {i}, w _ {i}}, g _ {i + 1} ^ {h _ {i + 1}, w _ {i + 1}}\\right). \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.838, + 0.47, + 0.903 + ], + "angle": 0, + "content": "In the equation, \\(D_{c}\\) is the cosine similarity, \\(g_{i}^{h_{i},w_{i}}\\) is the feature patch of frame \\(i\\) with the index of \\((h_i,w_i)\\), and \\(g_{i + 1}^{h_{i + 1},w_{i + 1}}\\) is the feature patch of frame \\(i + 1\\) with the index of \\((h_{i + 1},w_{i + 1})\\). With a feature patch at \\((h_i,w_i)\\) of \\(g_{i}\\) as an" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.09, + 0.892, + 0.265 + ], + "angle": 0, + "content": "example, the matrix \\(\\mathbf{M}_{i,i + 1}^{h_i,w_i}\\in \\mathbb{R}^{H\\times W}\\) can be regarded as a heatmap that reflects how much impact \\(g_{i}^{h_{i},w_{i}}\\) has on \\(g_{i + 1}\\), or more intuitively, the motion tendency of \\(g_{i}^{h_{i},w_{i}}\\) (see Figure 5 for illustration). It is similar to the definition of optical flow [17], which determines the movement of a pixel or superpixel. The difference between optical flow and motion matrix is that motion matrix does not strictly define a one-to-one relationship between the pixels or superpixels of the current frame and those of the next frame. It is a more practical assumption in the video prediction task that one current feature patch may influence several future feature patches." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.274, + 0.674, + 0.289 + ], + "angle": 0, + "content": "3.4. Matrix Prediction" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.297, + 0.892, + 0.39 + ], + "angle": 0, + "content": "Given the motion matrices of the past \\(T\\) frames \\(\\{\\mathbf{M}_{1,2},\\mathbf{M}_{2,3},\\dots,\\mathbf{M}_{T - 1,T}\\}\\), the matrix predictor \\(\\Psi\\) predicts the future matrices \\(\\{\\mathbf{M}_{T,T + 1},\\mathbf{M}_{T,T + 2},\\dots,\\mathbf{M}_{T,T'}\\}\\). Instead of predicting the motion matrices between the consecutive frames, we predict the ones between the last observed frame \\(I_{T}\\) and every future frame \\(I_{T + j},j\\in \\{1,2,\\dots,T'\\}\\), as" + }, + { + "type": "equation", + "bbox": [ + 0.515, + 0.413, + 0.892, + 0.438 + ], + "angle": 0, + "content": "\\[\n\\left\\{\\widehat {\\mathbf {M} _ {T , T + j} ^ {w , h}} \\right\\} = \\Psi \\left(\\left\\{\\mathbf {M} _ {i, i + 1} ^ {w, h} \\right\\}\\right), \\forall i \\in \\{1, 2, \\dots , T - 1 \\}, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.449, + 0.893, + 0.606 + ], + "angle": 0, + "content": "where \\(\\mathbf{M}_{i,i+1}^{w,h} \\in \\mathbb{R}^{H \\times W}\\), \\(w \\in \\{1,2,\\dots,\\frac{W}{S}\\}\\) and \\(h \\in \\{1,2,\\dots,\\frac{H}{S}\\}\\). This design aims to reduce the accumulative error during feature composition and is validated by the long-term prediction setting shown in Table 3. Since for this work, we focus on testing the function and performance of the MMVP framework, we report the use of a simple \\(3D\\) fully convolutional architecture to implement \\(\\Psi\\). Fellow researchers can choose to easily replace the implementation of \\(\\Psi\\) with more advanced temporal modules if they wish to pursue better performances." + }, + { + "type": "image", + "bbox": [ + 0.502, + 0.619, + 0.894, + 0.827 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.846, + 0.892, + 0.893 + ], + "angle": 0, + "content": "Figure 4: All scales of image features and the original frames can join the future composition with predicted motion matrices through pixel unshuffle and shuffle operations." + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "4276" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.091, + 0.36, + 0.108 + ], + "angle": 0, + "content": "3.5. Multi-scale Future Composition" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.115, + 0.47, + 0.16 + ], + "angle": 0, + "content": "The future composition step generates information for the future frames using the observed information and the motion matrices. It is formulated as" + }, + { + "type": "equation", + "bbox": [ + 0.12, + 0.17, + 0.47, + 0.212 + ], + "angle": 0, + "content": "\\[\n\\widehat {\\mathcal {X} _ {T + j}} = \\sum_ {i = 1} ^ {T} \\left(\\mathcal {X} _ {i} \\times \\prod_ {n = i} ^ {T - 1} \\mathbf {M} _ {n, n + 1} \\times \\widehat {\\mathbf {M} _ {T , T + j}}\\right). \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.22, + 0.471, + 0.598 + ], + "angle": 0, + "content": "As the equation indicates, instead of only using the information of the last observed frame, we use all observed information for future composition and lower the weight of earlier frames through repeated multiplication of the motion matrices. The \\(\\mathcal{X}\\) in the equation represents the observed information of the past frames. The information can be the output features of the image encoder with different scales \\(f_{i} \\in \\mathbb{R}^{H^{s} \\times W^{s} \\times C}\\), where \\(C\\) is the feature length; the information can also be the observed frames \\(I_{i} \\in \\mathbb{R}^{H \\times W \\times 3}\\). Since the motion matrices are constructed from a certain scale of image features, there will be incompatibilities between the matrices and some features. To enable matrix multiplication between the motion matrices and the observed features (at any scales) or images, we borrow the pixel unshuffle and shuffle operations from [39]. The pixel unshuffle operation reshapes features or images into the identical scale as the motion matrices for matrix multiplication. Afterward, the pixel shuffle operation reshapes the results of the matrix multiplication back to the original scales of the features or images. See Figure 4 for demonstration. This whole process involves little information loss. In Table 6, we examine the multi-scale feature composition design. We find out that in general, the system achieves better performance when more scales of features take part in the feature composition." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.609, + 0.245, + 0.626 + ], + "angle": 0, + "content": "3.6. Future Decoding" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.633, + 0.47, + 0.785 + ], + "angle": 0, + "content": "The future decoding procedure is used for aggregating and processing the composed features to formulate the final output. Since in the feature composition procedure, all scales of features are able to compose their corresponding scales of features for future frames, we adopt the decoder structure of UNet [37] with RRDB blocks [44] in the end to implement MMVP's image decoder. This design allows the composed features from all scales of image features, as well as the original images, to contribute to the final output. We use MSE loss to supervise the framework training." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.8, + 0.203, + 0.817 + ], + "angle": 0, + "content": "4. Experiment" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.471, + 0.903 + ], + "angle": 0, + "content": "In this section, we evaluate MMVP quantitatively and qualitatively against existing state-of-the-art methods on various publicly available datasets. In addition, we analyze MMVP through a set of ablation studies on the UCF Sports dataset to better illustrate our design logic." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.091, + 0.603, + 0.106 + ], + "angle": 0, + "content": "4.1. Datasets" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.115, + 0.894, + 0.146 + ], + "angle": 0, + "content": "We briefly review three widely used datasets and their configurations for MMVP evaluation." + }, + { + "type": "table_caption", + "bbox": [ + 0.544, + 0.154, + 0.847, + 0.169 + ], + "angle": 0, + "content": "Table 1: Experiment settings for each dataset." + }, + { + "type": "table", + "bbox": [ + 0.515, + 0.173, + 0.878, + 0.236 + ], + "angle": 0, + "content": "
DatasetResolutionTrainTest
UCF Sports512 × 5124 → 14 → 6
KTH128 × 12810 → 20 or 4010 → 20 or 40
Moving MNIST64 × 6410 → 1010 → 10
" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.248, + 0.892, + 0.566 + ], + "angle": 0, + "content": "UCF Sports [36] contains 150 video sequences collected from various sports scenes with 10 different action types including running, kicking, and diving. It is regarded as a challenging dataset given its low frame rate (10 fps), high resolution \\((480 \\times 720)\\), and complex motion patterns. The video sequences in this dataset contain both rapid foreground (e.g. athletes) and background movements (e.g. the camera motion). We perform two different training/validation splits of this dataset, splits from STRPM [5] and our own splits, to facilitate different evaluation purposes. We use the STRPM splits for performance comparison with other methods (Table 4). In STRPM, long video sequences are cut into several short clips; for a particular sequence, some of its clips may be put into the training split, and others into the validation split. To avoid the appearance features of certain sequences in the validation set to be exposed in the training set, and to thoroughly evaluate MMVP's capability of video prediction, we generate our own splits for UCF Sports, which choose \\(90\\%\\) of the video sequences from each action type to form the training samples, and the rest \\(10\\%\\) to form the validation samples." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.567, + 0.892, + 0.748 + ], + "angle": 0, + "content": "Notably, within the same validation set, the difficulty level of different samples varies a lot. Some easier video clips contain static backgrounds and slow-moving objects, while others are more difficult for involving drastic camera movement and/or fast-moving objects. To better understand the model's prediction ability in different scenarios, we apply certain thresholds of the structural similarity index measure (SSIM) between the last observed frame and the first future frame to divide the UCF Sports validation set into three subsets: the easy \\((\\mathrm{SSIM} \\leq 0.9)\\), intermediate \\((0.6 \\leq \\mathrm{SSIM} < 0.9)\\), and hard subsets \\((\\mathrm{SSIM} < 0.6)\\), which respectively take up \\(66\\%\\), \\(26\\%\\), and \\(8\\%\\) of the full set." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.749, + 0.894, + 0.809 + ], + "angle": 0, + "content": "We use our own UCF Sports splits in the ablation studies (Sec. 4.3). For comparisons, we also train and test STIP [4] (extension of STRPM [5]) and SimVP [12] on our own UCF Sports splits; see Table 6." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.894, + 0.902 + ], + "angle": 0, + "content": "KTH [38] contains videos of 25 individuals performing six types of actions, i.e., walking, jogging, running, boxing, hand-waving, and hand-clapping. Following previous works [43, 46, 12], we use persons 1-16 for training and persons 17-25 for validation. The videos in KTH are in grayscale, but the challenging part of this dataset is its ex" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "4277" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.121 + ], + "angle": 0, + "content": "periment setting, which requires the system to output 20 or 40 frames given only 10 past frames." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.122, + 0.471, + 0.258 + ], + "angle": 0, + "content": "Moving MNIST [41] is a synthetic dataset. Each sequence in the dataset consists of two digits moving independently within the \\(64 \\times 64\\) grid and bouncing off the boundary. During the training time, by assigning different initial locations and velocities to each digit, one can generate an infinite number of sequences, and train the system to predict the future 10 frames from the previous 10 frames. For fair comparisons, we use the pre-generated 10000 sequences[12] for validation." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.269, + 0.173, + 0.284 + ], + "angle": 0, + "content": "4.2. Metrics" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.292, + 0.471, + 0.489 + ], + "angle": 0, + "content": "We use the peak signal-to-noise ratio (PSNR) and structural similarity index measure (SSIM) to evaluate the image quality of the predicted frames. We use the implementation of PSNR and SSIM from the package scikit-learn [34]. For the UCF Sports dataset, we use Learned Perceptual Image Patch Similarity (LPIPS) [58] for better comparison with existing methods. LPIPS represents the perceptual quality of the predicted frames. It measures the feature distance of corresponding image patches between the predicted frames and the ground truth. Following the setting of these previous works, in the experiments on Moving MNIST, we use the sum of the mean squared error (MSE) from the entire frame to evaluate the image quality." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.5, + 0.231, + 0.515 + ], + "angle": 0, + "content": "4.3. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.523, + 0.47, + 0.599 + ], + "angle": 0, + "content": "We conduct the ablation study of future composition (Table 6), filter block (3rd and 4th rows of Table 2), and hyperparameters for both the image encoder/decoder and the matrix predictor (1st, 2nd, and 4th rows of Table 2) on our splits of the UCF Sports dataset." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.599, + 0.471, + 0.885 + ], + "angle": 0, + "content": "We first examine how the number of feature scales for feature composition impacts the results. Since we use the UNet structure with three times downsampling/upsampling operations to encode, we have four different scales of features for composition. For UCF Sports, the scales are \\(1, \\frac{1}{2}, \\frac{1}{8}, \\frac{1}{16}\\). The motion matrices are constructed using features of \\(\\frac{1}{8}\\) scale. From Table 6 3rd to 5th rows, we observe consistent performance boosts on all metrics and subsets when we involve more scales of features for composition. We then test if using images for feature composition also boosts performance. By comparing the 5th and 6th rows of Table 6, we can still see an increasing pattern. However, since the scale of the image is identical to the largest scale of the features, to avoid redundancy and possible conflicts, we remove the features of the largest scale and produce the results of the last row in Table 6. We then see a comparable result to the one that uses all scales of features as well as the image. We adopt the model setting of the last row for the rest of the experiments." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.886, + 0.47, + 0.901 + ], + "angle": 0, + "content": "As mentioned in Sec. 3.2, we do not directly use the out" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.183 + ], + "angle": 0, + "content": "put of the image encoder to construct the motion matrices. Instead, we add a filter block to filter out irrelevant features and help the motion matrices focus more on describing the temporal similarity regarding the motion-related features. Table 2 shows that the model with the filter block generally achieves better results on the UCF Sports validation set." + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.196, + 0.892, + 0.243 + ], + "angle": 0, + "content": "Table 2: Ablation study on UCF Sports with LPIPS metrics (the lower the better), including the feature length of image and motion, and the usage of the filter block (F-Block)." + }, + { + "type": "table", + "bbox": [ + 0.511, + 0.253, + 0.876, + 0.342 + ], + "angle": 0, + "content": "
ImgMotionF-BlockFullEasyIntermediateHardParam #
164✓0.11840.05920.18110.41680.70M
168✓0.11750.06000.17680.41220.71M
328×0.11240.05740.17290.38192.57M
328✓0.10620.05800.15690.35102.79M
STIPHR [4]0.16260.10660.22710.445018.05M
SimVP [12]0.13260.05840.19510.56003.47M
" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.348, + 0.892, + 0.424 + ], + "angle": 0, + "content": "Furthermore, Table 2 also shows an ablation study on the feature length of the appearance-related modules (image encoder and decoder) and the motion-related module (matrix predictor). We define the configuration of the second row as the MMVP-mini for Figure 1." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.435, + 0.756, + 0.45 + ], + "angle": 0, + "content": "4.4. Motion Matrix Visualization" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.458, + 0.892, + 0.61 + ], + "angle": 0, + "content": "In Figure 5, we visualize the predicted motion matrices for certain selected feature patches. In all the demonstrated samples, the many-to-many relationships described by the predicted motion matrices are able to accurately capture the feature patches moving tendency. They show that the motion matrix can describe a wide range of motion patterns and scenarios, including multiple objects (1st sample of UCF Sports), the single person moving (KTH), multiple persons moving and camera moving (2nd sample of UCF Sports), and synthesized motions (Moving MNIST)." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.62, + 0.794, + 0.636 + ], + "angle": 0, + "content": "4.5. Comparison with SOTA Methods" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.644, + 0.892, + 0.689 + ], + "angle": 0, + "content": "We compare MMVP with existing SOTA methods on three popular datasets: UCF Sports (STRPM [5] splits, Table 4), KTH (Table 3), and Moving MNIST (Table 5)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.69, + 0.892, + 0.901 + ], + "angle": 0, + "content": "On the UCF Sports dataset, we observe large performance gains by MMVP compared to other methods. As mentioned above, the motion patterns in UCF Sports are the most complex of the three datasets due to many difficult cases, e.g., fast movement, camera moving, and motion blur. But the two-stream design of MMVP has shown its ability in such complex scenarios. Meanwhile, the video resolution of UCF Sports is also the highest among the three datasets. Most existing methods in Table 4 are inherently not designed for high-resolution videos, which requires larger network capacities to maintain appearance information. Although STRPM [5] and STIP [4] proposed residual temporal modules designed for high-resolution videos and they could largely surpass previous methods on both" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "4278" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.148, + 0.086, + 0.837, + 0.319 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.327, + 0.896, + 0.391 + ], + "angle": 0, + "content": "Figure 5: Predicted motion matrix visualization. We highlight the selected feature patch(es) at \\((h,w)\\) in the last observed frame \\(I_{T}\\) in red and visualize their corresponding predicted motion matrices \\(\\mathbf{M}_{T,T + 1}^{h,w}\\in \\mathbb{R}^{H\\times W}\\) overlaying with the first future frame \\(I_{T + 1}\\). A brighter color indicates a higher predicted value. We select two samples for each dataset. From left to right, samples originate in the validation set of UCF Sports, KTH, and Moving MNIST." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.409, + 0.471, + 0.53 + ], + "angle": 0, + "content": "metrics, the appearance information loss in their methods is still unavoidable. MMVP, nevertheless, allows the image and multi-scale features to reach the decoder through a feature composing procedure, successfully minimizes the information loss, and achieves the best performance among all methods across all metrics. MMVP's success on the UCF Sports dataset validates its readiness for real-world applications, and its scalability for high-resolution videos." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.535, + 0.47, + 0.762 + ], + "angle": 0, + "content": "Another notable result is MMVP's ability in long-term information preservation; see Table 3. Despite having lower video resolutions and less complex motion patterns than UCF Sports, KTH as a real-world dataset still presents a difficulty as it requires systems to do long-term prediction given short-term observations. On the KTH dataset, MMVP achieves the #1 performance on SSIM metrics for both experiment settings with a small performance gap (27.54 to 26.35) in PSNR between the two settings. This is contributed by the design that the matrix predictor of MMVP predicts the temporal similarity matrices between the future frames and the last observed frame instead of their predecessors. Then, every predicted frame is composed of valid observed information. It reduces accumulated errors and ensures good performance for long-term prediction." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Compared to the performance gains on UCF Sports, MMVP does not show much advantage on the Moving MNIST dataset. One speculation is that with video prediction research advancing, the problem of two-digits Moving MNIST with low resolution \\((64\\times 64)\\) is nearly solved. With sufficient training time [12], current video prediction systems may all be able to achieve promising results. To further promote the growth of this field, researchers can consider more challenging datasets and experiment settings." + }, + { + "type": "table_caption", + "bbox": [ + 0.518, + 0.407, + 0.876, + 0.422 + ], + "angle": 0, + "content": "Table 3: Performance comparison on the KTH dataset" + }, + { + "type": "table", + "bbox": [ + 0.503, + 0.426, + 0.89, + 0.665 + ], + "angle": 0, + "content": "
MethodKTH10 → 20KTH10 → 40
SSIM ↑PSNR ↑SSIM ↑PSNR ↑
MCnet (ICLR2017) [43]0.80425.950.7323.89
ConvLSTM (NeurIPS2015) [40]0.71223.580.63922.85
SAVP (arXiv2018) [25]0.74625.380.70123.97
VPN (PMLR2017) [23]0.74623.76--
DFN (NeurIPS2016) [20]0.79427.260.65223.01
fRNN (ECCV2018) [32]0.77126.120.67823.77
Znet (ICME2019) [56]0.81727.58--
SV2Pi (ICLR2018) [1]0.82627.560.77825.92
SV2Pv (ICLR2018) [1]0.83827.790.78926.12
PredRNN (NeurIPS2017) [47]0.83927.550.70324.16
VarNet (IROS2018) [22]0.84328.480.73925.37
SVAP-VAE (arXiv2018) [25]0.85227.770.81126.18
PredRNN++ (ICML2018) [45]0.86528.470.74125.21
MSNET (BMVC2019) [26]0.87627.08--
E3d-LSTM (ICLR2019) [46]0.87929.310.81027.24
STMFANet (CVPR2020) [21]0.89329.850.85127.56
MMVP (ours)0.90627.540.88826.35
" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.687, + 0.893, + 0.868 + ], + "angle": 0, + "content": "Moreover, we analyze MMVP's performance on data of different difficulty levels using our own split of the UCF Sports dataset. We define the difficulty of a video using the SSIM between the last observed frame and the first frame to be predicted. This is because a lower SSIM indicates a larger difference between the two frames, and less possibility for a system to take the shortcut by using the residual information from past frames and not actually predicting the motion. Table 6 shows the quantitative evaluation compared with SimVP [12] and STIP [4]: as the difficulty level of the validation subset increases, the performance gap between MMVP and other methods also increases." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.893, + 0.902 + ], + "angle": 0, + "content": "Besides quantitative evaluation, we also showcase several qualitative visualizations in Figure 6 and compare them" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "4279" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.117, + 0.092, + 0.852, + 0.352 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.243, + 0.357, + 0.725, + 0.373 + ], + "angle": 0, + "content": "Figure 6: Qualitative results on our own splits of the UCF Sports dataset." + }, + { + "type": "table_caption", + "bbox": [ + 0.094, + 0.38, + 0.513, + 0.396 + ], + "angle": 0, + "content": "Table 4: Performance comparison on UCF Sports STRPM split" + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.4, + 0.526, + 0.603 + ], + "angle": 0, + "content": "
Methodt=5t=10
PSNR↑LPIPS×100↓PSNR↑LPIPS×100↓
ConvLSTM (NeurIPS2015) [40]26.4332.2017.8058.78
BeyondMSE (ICLR2016) [30]26.4229.0118.4655.28
PredRNN (NeurIPS2017) [47]27.1728.1519.6555.34
PredRNN++ (ICML2018) [45]27.2626.8019.6756.79
SAVP (arXiv2018) [25]27.3525.4519.9049.91
SV2P (ICLR2018) [1]27.4425.8919.9751.33
E3D-LSTM (ICLR2019) [46]27.9825.1320.3347.76
CycleGAN (CVPR2019) [24]27.9922.9519.9944.93
CrevNet (ICLR2020) [55]28.2323.8720.3348.15
MotionRNN (CVPR2021) [51]27.6724.2320.0149.20
STRPM (CVPR2022) [5]28.5420.6920.5941.11
STIP (arXiv2022) [4]30.7512.7321.8339.67
DMVFN (CVPR2023) [19]30.0510.2422.6722.50
MMVP (Ours)31.687.8823.2522.24
" + }, + { + "type": "table_caption", + "bbox": [ + 0.579, + 0.412, + 0.857, + 0.427 + ], + "angle": 0, + "content": "Table 5: Comparisons on Moving MNIST" + }, + { + "type": "table", + "bbox": [ + 0.591, + 0.431, + 0.848, + 0.571 + ], + "angle": 0, + "content": "
MethodMSESSIM
ConvLSTM (NIPS 2015) [40]103.30.707
PredRNN (NIPS 2017) [47]56.80.867
PredRNN-V2 (Arxiv 2021) [48]48.40.891
CausalLSTM (ICML 2018) [45]46.50.898
MIM (CVPR 2019) [49]44.20.910
E3D-LSTM (ICLR 2018) [46]41.30.920
PhyDNet (CVPR 2020) [14]24.40.947
CrevNet (ICLR 2020) [55]22.30.949
SimVP (CVPR 2022) [12]23.80.948
MMVP(ours)22.20.952
" + }, + { + "type": "table_caption", + "bbox": [ + 0.087, + 0.619, + 0.881, + 0.635 + ], + "angle": 0, + "content": "Table 6: Ablation study on sources for future composition and the comparison with other SOTA methods on UCF Sports." + }, + { + "type": "table", + "bbox": [ + 0.085, + 0.639, + 0.885, + 0.741 + ], + "angle": 0, + "content": "
MethodComposition sourceFull setEasy (SSIM ≥ 0.9)Intermediate (0.6 ≤ SSIM < 0.9)Hard (SSIM < 0.6)Param#
Img11/21/81/16SSIM ↑PSNR ↑LPIPS ↓SSIM ↑PSNR ↑LPIPS ↓SSIM ↑PSNR ↑LPIPS ↓SSIM ↑PSNR ↑LPIPS ↓
STIPHR [4]-0.881728.170.16260.949130.650.10660.835123.970.22710.467315.970.445018.05M
SimVP [12]-0.918929.970.13260.966432.870.05840.884525.790.19510.626718.990.56003.47M
MMVP×××✓✓0.900028.310.18740.937530.430.13420.875925.360.23040.659319.900.49922.75M
××✓✓✓0.928430.140.11150.966732.790.06030.893726.110.16930.715920.710.35702.79M
×✓✓✓✓0.929630.220.10640.966932.870.05760.896526.260.15710.719920.760.35552.80M
✓✓✓✓✓0.929630.290.10510.967532.990.05670.895826.220.15540.717520.760.35172.80M
✓×✓✓✓0.930030.350.10620.967433.050.05800.897026.290.15690.720320.840.35102.79M
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.761, + 0.471, + 0.897 + ], + "angle": 0, + "content": "with SimVP [12] which achieved the second-best performance on our splits of the UCF Sports dataset. We especially select four samples in the hard and intermediate subsets for visualization. The first sample in Figure 6 shows a far-away object with long-distance movement. This is caused by the low fps of the dataset. MMVP accurately captures the displacement of the object while not losing the color and shape of the object. The challenge of the second sample in Figure 6 is also typical to UFC Sports," + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.761, + 0.892, + 0.897 + ], + "angle": 0, + "content": "i.e. fast movement with motion blur. MMVP is able to recover the correct shape of the athletes' feet even if they are blurred in the observed frames. The third and fourth samples both show a fast camera movement, with and without large foreground movements. Camera moving with complex backgrounds is extremely difficult for video prediction. Even SimVP, which generated high-quality images for most of the datasets, barely captured the camera movements in these two samples and caused drastic blurs. Benefiting from" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "4280" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.122 + ], + "angle": 0, + "content": "its appearance-agnostic motion prediction module, MMVP achieved impressive performance in such cases." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.138, + 0.192, + 0.154 + ], + "angle": 0, + "content": "5. Discussion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.164, + 0.473, + 0.389 + ], + "angle": 0, + "content": "From Table 2 and Table 6 in Sec. 4, we observe that the proposed MMVP framework can always achieve better or comparable performance with significantly fewer parameters compared to the other SOTA methods. To better understand the high efficiency of MMVP, we break down a video prediction system into three components: i) content encoder, which encodes the image sequences; ii) prediction-related modules, which take charge of predicting features for future frames based on the output of the content encoder; iii) content decoder, which decodes the output of the predicted features output by the prediction-related modules. Then we examine the model size for each component in three video prediction systems: STIP [4], SimVP [12], and the proposed MMVP (configurations follow the second row and the fourth row in Table 2); see Table 7." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.39, + 0.473, + 0.68 + ], + "angle": 0, + "content": "In Table 7, prediction-related modules in STIP [4] and SimVP [12] handle both motion and appearance features. However, in MMVP, prediction-related modules specifically handle only the motion features, leaving all appearance features to the content encoder and decoder. The most noticeable fact from Table 7 is that in STIP [4] and SimVP [12], the prediction-related modules take majority of the model parameters (the ratios are \\(99.7\\%\\) and \\(99.4\\%\\) respectively). In contrast, motion-related modules in MMVP only take \\(14.5\\%\\) and \\(15.9\\%\\) of the parameters. This fact supports our argument in Sec. 1 that decoupling motion prediction and appearance maintenance effectively avoid the cumbersome structures of the prediction modules and largely improve the prediction efficiency. Another observation is that despite the small size, the prediction-related modules in MMVP can still support high-quality motion prediction. This validates the efficiency of the motion matrices when describing the motion information, which results in a lightweight design of the prediction module." + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.693, + 0.47, + 0.738 + ], + "angle": 0, + "content": "Table 7: Model size breakdown. The numerical values are the number of parameters taken by each component in the video prediction systems." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.75, + 0.468, + 0.811 + ], + "angle": 0, + "content": "
MethodContent EncoderPrediction ModulesContent DecoderTotal
STIPHR [4]29.86K17994.8K29.54K18054.2K
SimVP [12]7.5k3447.1K11.7K3466.3K
MMVP-mini369.4K113.2K228.3K710.9K
MMVP1472.2K404.9K911.9K2789.0K
" + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.845, + 0.197, + 0.86 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.871, + 0.47, + 0.9 + ], + "angle": 0, + "content": "The proposed Motion-Matrix-based Video Prediction framework (MMVP) is an end-to-end trainable two-stream" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.895, + 0.259 + ], + "angle": 0, + "content": "pipeline. MMVP uses motion matrices to represent appearance-agnostic motion patterns. As the sole input of the motion prediction module in MMVP, the motion matrix can i) describe the many-to-many relationships between feature patches without training for extra modules; ii) intuitively compose future features with multi-scale image features through matrix multiplication. It helps the motion prediction become more focused, and efficiently reduces the information loss in appearance. Extensive experiments demonstrate the superiority of MMVP compared to existing SOTA methods in both the model size and performance." + }, + { + "type": "title", + "bbox": [ + 0.502, + 0.274, + 0.597, + 0.289 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.508, + 0.299, + 0.895, + 0.354 + ], + "angle": 0, + "content": "[1] Mohammad Babaeizadeh, Chelsea Finn, Dumitru Erhan, Roy H Campbell, and Sergey Levine. Stochastic variational video prediction. arXiv preprint arXiv:1710.11252, 2017. 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.357, + 0.895, + 0.413 + ], + "angle": 0, + "content": "[2] Xinzhu Bei, Yanchao Yang, and Stefano Soatto. Learning semantic-aware dynamics for video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 902-912, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.415, + 0.895, + 0.483 + ], + "angle": 0, + "content": "[3] Po-Rong Chang and Jen-Tsung Hu. Optimal nonlinear adaptive prediction and modeling ofmpeg video in atm networks using pipelined recurrent neural networks. IEEE Journal on Selected Areas in Communications, 15(6):1087-1100, 1997. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.486, + 0.895, + 0.556 + ], + "angle": 0, + "content": "[4] Zheng Chang, Xinfeng Zhang, Shanshe Wang, Siwei Ma, and Wen Gao. Stip: A spatiotemporal information-preserving and perception-augmented model for high-resolution video prediction. arXiv preprint arXiv:2206.04381, 2022. 1, 2, 3, 5, 6, 7, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.558, + 0.895, + 0.639 + ], + "angle": 0, + "content": "[5] Zheng Chang, Xinfeng Zhang, Shanshe Wang, Siwei Ma, and Wen Gao. Strpm: A spatiotemporal residual predictive model for high-resolution video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13946-13955, 2022. 1, 2, 3, 5, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.642, + 0.894, + 0.685 + ], + "angle": 0, + "content": "[6] Emily L Denton et al. Unsupervised learning of disentangled representations from video. Advances in neural information processing systems, 30, 2017. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.687, + 0.895, + 0.742 + ], + "angle": 0, + "content": "[7] Duarte Duque, Henrique Santos, and Paulo Cortez. Prediction of abnormal behaviors for intelligent video surveillance systems. In 2007 IEEE Symposium on Computational Intelligence and Data Mining, pages 362-367. IEEE, 2007. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.744, + 0.895, + 0.8 + ], + "angle": 0, + "content": "[8] Frederik Ebert, Chelsea Finn, Sudeep Dasari, Annie Xie, Alex Lee, and Sergey Levine. Visual foresight: Model-based deep reinforcement learning for vision-based robotic control. arXiv preprint arXiv:1812.00568, 2018. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.802, + 0.895, + 0.857 + ], + "angle": 0, + "content": "[9] Chelsea Finn and Sergey Levine. Deep visual foresight for planning robot motion. In 2017 IEEE International Conference on Robotics and Automation (ICRA), pages 2786-2793. IEEE, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.859, + 0.895, + 0.902 + ], + "angle": 0, + "content": "[10] Hang Gao, Huazhe Xu, Qi-Zhi Cai, Ruth Wang, Fisher Yu, and Trevor Darrell. Disentangling propagation and generation for video prediction. In Proceedings of the IEEE/CVF" + }, + { + "type": "list", + "bbox": [ + 0.502, + 0.299, + 0.895, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.514, + 0.957 + ], + "angle": 0, + "content": "4281" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.093, + 0.47, + 0.119 + ], + "angle": 0, + "content": "international conference on computer vision, pages 9006-9015, 2019. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.121, + 0.47, + 0.189 + ], + "angle": 0, + "content": "[11] Xiaojie Gao, Yueming Jin, Qi Dou, Chi-Wing Fu, and Pheng-Ann Heng. Accurate grid keypoint learning for efficient video prediction. In 2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages 5908–5915. IEEE, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.19, + 0.469, + 0.258 + ], + "angle": 0, + "content": "[12] Zhangyang Gao, Cheng Tan, Lirong Wu, and Stan Z Li. Simvp: Simpler yet better video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3170-3180, 2022. 1, 2, 5, 6, 7, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.26, + 0.469, + 0.302 + ], + "angle": 0, + "content": "[13] Bernd Girod. The efficiency of motion-compensating prediction for hybrid coding of video sequences. IEEE Journal on selected areas in communications, 5(7):1140-1154, 1987. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.302, + 0.469, + 0.37 + ], + "angle": 0, + "content": "[14] Vincent Le Guen and Nicolas Thome. Disentangling physical dynamics from unknown factors for unsupervised video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11474-11484, 2020. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.371, + 0.469, + 0.426 + ], + "angle": 0, + "content": "[15] Agrim Gupta, Stephen Tian, Yunzhi Zhang, Jiajun Wu, Roberto Martín-Martín, and Li Fei-Fei. Maskvit: Masked visual pre-training for video prediction. arXiv preprint arXiv:2206.11894, 2022.3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.427, + 0.469, + 0.482 + ], + "angle": 0, + "content": "[16] Noriaki Hirose, Fei Xia, Roberto Martín-Martín, Amir Sadeghian, and Silvio Savarese. Deep visual mpc-policy learning for navigation. IEEE Robotics and Automation Letters, 4(4):3184-3191, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.483, + 0.469, + 0.511 + ], + "angle": 0, + "content": "[17] Berthold KP Horn and Brian G Schunck. Determining optical flow. Artificial intelligence, 17(1-3):185–203, 1981. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.511, + 0.469, + 0.566 + ], + "angle": 0, + "content": "[18] Jun-Ting Hsieh, Bingbin Liu, De-An Huang, Li F Fei-Fei, and Juan Carlos Niebles. Learning to decompose and disentangle representations for video prediction. Advances in neural information processing systems, 31, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.567, + 0.469, + 0.621 + ], + "angle": 0, + "content": "[19] Xiaotao Hu, Zhewei Huang, Ailin Huang, Jun Xu, and Shuchang Zhou. A dynamic multi-scale voxel flow network for video prediction. arXiv preprint arXiv:2303.09875, 2023. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.622, + 0.469, + 0.664 + ], + "angle": 0, + "content": "[20] Xu Jia, Bert De Brabandere, Tinne Tuytelaars, and Luc V Gool. Dynamic filter networks. Advances in neural information processing systems, 29, 2016. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.664, + 0.469, + 0.748 + ], + "angle": 0, + "content": "[21] Beibei Jin, Yu Hu, Qiankun Tang, Jingyu Niu, Zhiping Shi, Yinhe Han, and Xiaowei Li. Exploring spatial-temporal multi-frequency analysis for high-fidelity and temporal-consistency video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4554-4563, 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.748, + 0.469, + 0.816 + ], + "angle": 0, + "content": "[22] Beibei Jin, Yu Hu, Yiming Zeng, Qiankun Tang, Shice Liu, and Jing Ye. Varnet: Exploring variations for unsupervised video prediction. In 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages 5801-5806. IEEE, 2018. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.469, + 0.873 + ], + "angle": 0, + "content": "[23] Nal Kalchbrenner, Aäron Oord, Karen Simonyan, Ivo Danihelka, Oriol Vinyals, Alex Graves, and Koray Kavukcuoglu. Video pixel networks. In International Conference on Machine Learning, pages 1771-1779. PMLR, 2017. 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.47, + 0.902 + ], + "angle": 0, + "content": "[24] Yong-Hoon Kwon and Min-Gyu Park. Predicting future frames using retrospective cycle gan. In Proceedings of" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.093, + 0.47, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1811-1820, 2019. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.121, + 0.892, + 0.176 + ], + "angle": 0, + "content": "[25] Alex X Lee, Richard Zhang, Frederik Ebert, Pieter Abbeel, Chelsea Finn, and Sergey Levine. Stochastic adversarial video prediction. arXiv preprint arXiv:1804.01523, 2018. 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.179, + 0.892, + 0.233 + ], + "angle": 0, + "content": "[26] Jungbeom Lee, Jangho Lee, Sungmin Lee, and Sungroh Yoon. Mutual suppression network for video prediction using disentangled features. arXiv preprint arXiv:1804.04810, 2018. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.235, + 0.892, + 0.291 + ], + "angle": 0, + "content": "[27] Xiaodan Liang, Lisa Lee, Wei Dai, and Eric P Xing. Dual motion gan for future-flow embedded video prediction. In proceedings of the IEEE international conference on computer vision, pages 1744-1752, 2017. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.293, + 0.892, + 0.348 + ], + "angle": 0, + "content": "[28] Jianping Lin, Dong Liu, Houqiang Li, and Feng Wu. M-lvc: Multiple frames prediction for learned video compression. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3546-3554, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.349, + 0.892, + 0.417 + ], + "angle": 0, + "content": "[29] Bowen Liu, Yu Chen, Shiyu Liu, and Hun-Seok Kim. Deep learning in latent space for video prediction and compression. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 701-710, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.42, + 0.892, + 0.461 + ], + "angle": 0, + "content": "[30] Michael Mathieu, Camille Couprie, and Yann LeCun. Deep multi-scale video prediction beyond mean square error. arXiv preprint arXiv:1511.05440, 2015. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.463, + 0.892, + 0.517 + ], + "angle": 0, + "content": "[31] Tomas Mikolov, Martin Karafiát, Lukas Burget, Jan Cernocký, and Sanjeev Khudanpur. Recurrent neural network based language model. In *Interspeech*, volume 2, pages 1045–1048. Makuhari, 2010. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.519, + 0.892, + 0.575 + ], + "angle": 0, + "content": "[32] Marc Oliu, Javier Selva, and Sergio Escalera. Folded recurrent neural networks for future video prediction. In Proceedings of the European Conference on Computer Vision (ECCV), pages 716-731, 2018. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.577, + 0.892, + 0.659 + ], + "angle": 0, + "content": "[33] Sergiu Oprea, Pablo Martinez-Gonzalez, Alberto Garcia-Garcia, John Alejandro Castro-Vargas, Sergio Orts-Escalano, Jose Garcia-Rodriguez, and Antonis Argyros. A review on deep learning techniques for video prediction. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(6):2806-2826, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.661, + 0.892, + 0.743 + ], + "angle": 0, + "content": "[34] F. Pedregosa, G. Varoquaux, A. Gramfort, V. Michel, B. Thirion, O. Grisel, M. Blondel, P. Prettenhofer, R. Weiss, V. Dubourg, J. Vanderplas, A. Passos, D. Cournaepau, M. Brucher, M. Perrot, and E. Duchesnay. Scikit-learn: Machine learning in Python. Journal of Machine Learning Research, 12:2825-2830, 2011. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.746, + 0.892, + 0.787 + ], + "angle": 0, + "content": "[35] Ruslan Rakhimov, Denis Volkhonskiy, Alexey Artemov, Denis Zorin, and Evgeny Burnaev. Latent video transformer. arXiv preprint arXiv:2006.10704, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.789, + 0.892, + 0.856 + ], + "angle": 0, + "content": "[36] Mikel D Rodriguez, Javed Ahmed, and Mubarak Shah. Action mach a spatio-temporal maximum average correlation height filter for action recognition. In 2008 IEEE conference on computer vision and pattern recognition, pages 1-8. IEEE, 2008. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.859, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[37] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image com" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.956 + ], + "angle": 0, + "content": "4282" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.468, + 0.12 + ], + "angle": 0, + "content": "puting and computer-assisted intervention, pages 234-241. Springer, 2015. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.47, + 0.177 + ], + "angle": 0, + "content": "[38] Christian Schuldt, Ivan Laptev, and Barbara Caputo. Recognizing human actions: a localsvm approach. In Proceedings of the 17th International Conference on Pattern Recognition, 2004.ICPR 2004., volume 3,pages 32-36.IEEE,2004.2,5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.179, + 0.471, + 0.262 + ], + "angle": 0, + "content": "[39] Wenzhe Shi, Jose Caballero, Ferenc Huszár, Johannes Totz, Andrew P Aitken, Rob Bishop, Daniel Rueckert, and Zehan Wang. Real-time single image and video super-resolution using an efficient sub-pixel convolutional neural network. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1874-1883, 2016. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.264, + 0.469, + 0.332 + ], + "angle": 0, + "content": "[40] Xingjian Shi, Zhourong Chen, Hao Wang, Dit-Yan Yeung, Wai-Kin Wong, and Wang-chun Woo. Convolutional LSTM network: A machine learning approach for precipitation nowcasting. Advances in neural information processing systems, 28, 2015. 3, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.334, + 0.469, + 0.39 + ], + "angle": 0, + "content": "[41] Nitish Srivastava, Elman Mansimov, and Ruslan Salakhudinov. Unsupervised learning of video representations using lstms. In International conference on machine learning, pages 843-852. PMLR, 2015. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.392, + 0.469, + 0.447 + ], + "angle": 0, + "content": "[42] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.449, + 0.469, + 0.503 + ], + "angle": 0, + "content": "[43] Ruben Villegas, Jimei Yang, Seunghoon Hong, Xunyu Lin, and Honglak Lee. Decomposing motion and content for natural video sequence prediction. arXiv preprint arXiv:1706.08033, 2017. 2, 3, 5, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.505, + 0.469, + 0.575 + ], + "angle": 0, + "content": "[44] Xintao Wang, Ke Yu, Shixiang Wu, Jinjin Gu, Yihao Liu, Chao Dong, Yu Qiao, and Chen Change Loy. Esrgan: Enhanced super-resolution generative adversarial networks. In Proceedings of the European conference on computer vision (ECCV) workshops, pages 0–0, 2018. 3, 4, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.577, + 0.469, + 0.646 + ], + "angle": 0, + "content": "[45] Yunbo Wang, Zhifeng Gao, Mingsheng Long, Jianmin Wang, and S Yu Philip. Predrnn++: Towards a resolution of the deep-in-time dilemma in spatiotemporal predictive learning. In International Conference on Machine Learning, pages 5123-5132. PMLR, 2018. 1, 2, 3, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.647, + 0.469, + 0.702 + ], + "angle": 0, + "content": "[46] Yunbo Wang, Lu Jiang, Ming-Hsuan Yang, Li-Jia Li, Mingsheng Long, and Li Fei-Fei. Eidetic 3d LSTM: A model for video prediction and beyond. In International conference on learning representations, 2018. 1, 2, 3, 5, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.704, + 0.469, + 0.771 + ], + "angle": 0, + "content": "[47] Yunbo Wang, Mingsheng Long, Jianmin Wang, Zhifeng Gao, and Philip S Yu. Predrnn: Recurrent neural networks for predictive learning using spatiotemporal lstms. Advances in neural information processing systems, 30, 2017. 1, 2, 3, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.775, + 0.469, + 0.844 + ], + "angle": 0, + "content": "[48] Yunbo Wang, Haixu Wu, Jianjin Zhang, Zhifeng Gao, Jian-min Wang, Philip Yu, and Mingsheng Long. Predrnn: A recurrent neural network for spatiotemporal predictive learning. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[49] Yunbo Wang, Jianjin Zhang, Hongyu Zhu, Mingsheng Long, Jianmin Wang, and Philip S Yu. Memory in memory: A predictive neural network for learning higher-order nonstationarity from spatiotemporal dynamics. In Proceedings" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9154-9162, 2019. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.122, + 0.892, + 0.162 + ], + "angle": 0, + "content": "[50] Dirk Weissenborn, Oscar Täckström, and Jakob Uszkoreit. Scaling autoregressive video models. arXiv preprint arXiv:1906.02634, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.165, + 0.894, + 0.233 + ], + "angle": 0, + "content": "[51] Haixu Wu, Zhiyu Yao, Jianmin Wang, and Mingsheng Long. Motionrnn: A flexible model for video prediction with spacetime-varying motions. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 15435-15444, 2021. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.235, + 0.894, + 0.29 + ], + "angle": 0, + "content": "[52] Yue Wu, Qiang Wen, and Qifeng Chen. Optimizing video prediction via video frame interpolation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 17814-17823, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.292, + 0.892, + 0.347 + ], + "angle": 0, + "content": "[53] Ren Yang, Radu Timofte, and Luc Van Gool. Advancing learned video compression with in-loop frame prediction. IEEE Transactions on Circuits and Systems for Video Technology, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.349, + 0.892, + 0.389 + ], + "angle": 0, + "content": "[54] Wei Yu, Yichao Lu, Steve Easterbrook, and Sanja Fidler. Crevnet: Conditionally reversible video prediction. arXiv preprint arXiv:1910.11577, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.391, + 0.892, + 0.432 + ], + "angle": 0, + "content": "[55] Wei Yu, Yichao Lu, Steve Easterbrook, and Sanja Fidler. Efficient and information-preserving future frame prediction and beyond. 2020. 1, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.434, + 0.892, + 0.5 + ], + "angle": 0, + "content": "[56] Jianjin Zhang, Yunbo Wang, Mingsheng Long, Wang Jian-min, and S Yu Philip. Z-order recurrent neural networks for video prediction. In 2019 IEEE International Conference on Multimedia and Expo (ICME), pages 230-235. IEEE, 2019. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.504, + 0.892, + 0.559 + ], + "angle": 0, + "content": "[57] Qianqian Zhang, Guorui Feng, and Hanzhou Wu. Surveillance video anomaly detection via non-local u-net frame prediction. Multimedia Tools and Applications, 81(19):27073-27088, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.561, + 0.892, + 0.63 + ], + "angle": 0, + "content": "[58] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 586-595, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.631, + 0.892, + 0.686 + ], + "angle": 0, + "content": "[59] Xianguo Zhang, Tiejun Huang, Yonghong Tian, and Wen Gao. Background-modeling-based adaptive prediction for surveillance video coding. IEEE Transactions on Image Processing, 23(2):769-784, 2013. 1" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.686 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.515, + 0.956 + ], + "angle": 0, + "content": "4283" + } + ] +] \ No newline at end of file diff --git a/2023/MMVP_ Motion-Matrix-Based Video Prediction/2d057465-769a-4de5-aaaa-89b4c330116e_origin.pdf b/2023/MMVP_ Motion-Matrix-Based Video Prediction/2d057465-769a-4de5-aaaa-89b4c330116e_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..10f2308eb998b4b2fd217daca0bc2d360ca6c9c2 --- /dev/null +++ b/2023/MMVP_ Motion-Matrix-Based Video Prediction/2d057465-769a-4de5-aaaa-89b4c330116e_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:511f91cb2b6e172b13f14515007cf8e3bbe10208db5d616d953f60fe2db183b5 +size 9092429 diff --git a/2023/MMVP_ Motion-Matrix-Based Video Prediction/full.md b/2023/MMVP_ Motion-Matrix-Based Video Prediction/full.md new file mode 100644 index 0000000000000000000000000000000000000000..cdfebcdcfeb5a3110e9d450213f7dfed043972d1 --- /dev/null +++ b/2023/MMVP_ Motion-Matrix-Based Video Prediction/full.md @@ -0,0 +1,303 @@ +# MMVP: Motion-Matrix-based Video Prediction + +Yiqi Zhong $^{1*}$ Luming Liang $^{2*}$ Ilya Zharkov $^{2}$ Ulrich Neumann $^{1*}$ $^{1}$ University of Southern California $^{2}$ Microsoft + +1{yiqizhon,uneumann}@usc.edu 2{lulian,zharkov}@microsoft.com + +# Abstract + +A central challenge of video prediction lies where the system has to reason the objects' future motions from image frames while simultaneously maintaining the consistency of their appearances across frames. This work introduces an end-to-end trainable two-stream video prediction framework, Motion-Matrix-based Video Prediction (MMVP), to tackle this challenge. Unlike previous methods that usually handle motion prediction and appearance maintenance within the same set of modules, MMVP decouples motion and appearance information by constructing appearance-agnostic motion matrices. The motion matrices represent the temporal similarity of each and every pair of feature patches in the input frames, and are the sole input of the motion prediction module in MMVP. This design improves video prediction in both accuracy and efficiency, and reduces the model size. Results of extensive experiments demonstrate that MMVP outperforms state-of-the-art systems on public data sets by non-negligible large margins ( $\approx$ 1 db in PSNR, UCF Sports) in significantly smaller model sizes (84% the size or smaller). Please refer to this link for the official code and the datasets used in this paper. + +# 1. Introduction + +Video prediction aims at predicting future frames from limited past frames. It is a longstanding yet unsolved problem studied for decades [13, 3]. Advancing research in this area benefits various applications such as video compression [29, 53, 28], surveillance systems [57, 59, 7], and robotics [9, 16, 8]. The task can be essentially broken down into two sub-tasks: i) motion prediction and ii) frame synthesis. Each sub-task has its unique goal that cannot be simply accomplished by achieving the other one. For the sub-task of motion prediction, systems need to reason the future movements of objects/backgrounds by discovering the motion cues hidden in the past frames. Whereas for + +the sub-task of frame synthesis, systems need to maintain appearance features and generate future frames that keep appearance consistency. These separated goals make video prediction inherently much more difficult than the individual task of normal motion prediction or content synthesis. + +![](images/c745e68edda03c063b3ca4bf4e348a5632bef93014e68409d91f91f0e13dfdc7.jpg) +Figure 1: Performance comparison on UCF Sports with STIP [4] and SimVP [12]. The hard subset contains samples where SSIM between the last observed frame and the first future frame is smaller than 0.6, which indicates drastic motion patterns (data is from Tables 2 and 6). + +Most existing works in video prediction are based on a single-stream pipeline that conducts motion prediction and appearance feature extraction for frame synthesis within the same set of modules. Their systems [47, 45, 46, 55, 5, 4] usually grow out of advanced network structures for sequential data analysis, such as recurrent neural networks (RNNs) [31] and transformers [42]. One shared characteristic of those methods is that they show excellent capabilities in capturing complex motion patterns but lower capabilities in appearance maintenance, yielding "correct" but not "good" synthesized frames. The reason behind this is that those methods usually contain complicated spatial-temporal feature extraction and state transition operations, which can cause unavoidable appearance information loss. + +![](images/eafe28ca599c68dc3be11a323c3d5ba4d42dce837b24bae62f4cadb44370bb84.jpg) +Figure 2: MMVP is a two-stream video prediction framework. It decouples motion prediction and appearance maintenance, and it reunites motion and appearance features through feature composition operation. + +Researchers have proposed several solutions to mitigate appearance information loss; the most common approaches are introducing sophisticated appearance-aware state transition unit [5, 4, 54], or adding frequent feature shortcuts from previous frames [12, 46, 47, 45]. However, the former solution tends to build cumbersome models with a huge number of parameters; and for the latter solution, too much residual information from previous frames can cause a larger performance drop for hard cases such as videos with fast movements and/or moving cameras. Figure 1 shows the comparison between STIP [4] (an example of the former solution) and SimVP [12] (an example of the latter solution). + +To avoid running into possible trade-offs between motion and appearance in single-stream pipelines, a few works have explored two-stream pipelines [27, 2, 10, 43, 11], decoupling motion prediction and appearance maintenance. However, they either require auxiliary sub-networks such as optical flow estimator [27, 52] and key point detector [11] to generate motion representations, which complicates video prediction and reduces the generalizability of systems; or they do not provide an efficient solution to reunite the predicted motion and the appearance features [6, 43]. + +With these gaps in current research, we introduce a novel two-stream, end-to-end trainable framework for video prediction: Motion-Matrix-based Video Prediction (MMVP) (see Figure 2 for the framework overview). As the name indicates, MMVP uses motion matrices as the decoupled motion representation of video frames. The motion matrix is a 4D matrix representing the image feature patches of consecutive frames (see Figure 3 I). As motion matrices are the sole input of the matrix predictor (i.e., the motion prediction module in MMVP), MMVP specifies the hidden motion information and makes the matrix predictor only focus on motion-related information. For the reunion of motion and appearance features, MMVP gets inspiration from the image autoencoder. It first embeds the past frames individually through an image encoder. Then it composes the embedding of the future frames using the predicted motion + +matrices output by the matrix predictor and the past frames' embeddings through matrix multiplication (see Figure 3 II). Then, an image decoder decodes the composed embeddings into the predicted future frames. + +The advantage of MMVP is three-fold: (i) MMVP decouples motion and appearance by constructing motion matrices, requiring no extra construction modules; (ii) unlike optical flow that describes the one-to-one relationship between pixels, motion matrices describe the many-to-many relationship between feature patches, and are more flexible and applicable for real-world data; (iii) MMVP reunites the appearance and motion prediction results through matrix multiplication, which is interpretable and of little information loss. The advantages make MMVP a much more compact model with significantly fewer parameters yet still matching SOTA methods in performance. We validate MMVP on three datasets, UCF Sports [36], KTH [38], and MovingMNIST [41]. Experiments show that MMVP matches or surpasses SOTA methods on all three datasets across metrics. Specifically, compared to STIP [4], MMVP uses $84\%$ fewer parameters (18M vs. 2.8M) but achieves $38\%$ better performance in the LPIPS metric (12.73 vs. 7.88) on the UCF Sports dataset (Table 4). + +# 2. Related Works + +Good video prediction systems should not only accurately reason the future motions of the objects but also maintain their appearances and synthesize consistent future frames. As the video resolution has become increasingly higher today, researchers should additionally consider the scalability and efficiency of video prediction systems [33]. + +Most video prediction works to date adopt a single-stream pipeline that grows out of advanced techniques in sequential data analysis. Those techniques usually contain sophisticated spatial-temporal feature extraction operations and state transitions, which result in appearance information loss. Thus, researchers tend to modify the techniques to let them attend more to appearance mainte + +![](images/3871523fb7da684852f58c769c660e4fbf40bdde955559bd806b9fefc38611de.jpg) +I. Appearance-agnostic Motion Matrix M +II. Future Composition +Figure 3: MMVP relies on the motion matrix $\mathbf{M}$ . $\mathbf{M}$ is an appearance-agnostic motion representation that measures the cosine similarity between the feature patches of two consecutive frames. Information of the past frames $\{\mathcal{X}_0,\dots,\mathcal{X}_T\}$ can compose the future information $\{\widehat{\mathcal{X}}_{T + 1},\dots,\widehat{\mathcal{X}_{T^{\prime}}}\}$ through matrix multiplication $\otimes$ with $\mathbf{M}$ . + +![](images/525a8701d8f92d8a2bd93b2f6579f840546571e3ab82f27bcdea0a7ee7e13506.jpg) + +nance [47, 40, 45, 5, 4, 46, 18]. Based on ConvLSTM [40], PredRNN [47] propose a novel memory state transition method between the recurrent nodes to help the appearance features from observations be delivered to the final prediction. E3D-LSTM [46] integrated 3D convolution operations to help emphasize the short-term appearance. CrevNet [23] uses a conditionally reversible network to preserve the information from the past frames. More recently, the progress in temporal modeling made by transformer-based methods [42] has drawn more attention. The field starts to see works that use transformers in video prediction tasks [15, 50, 35]. These works have a better information aggregation capability and less appearance information loss, but they usually have a huge number of parameters and lack scalability to higher-resolution videos. + +Seeking an alternative solution to video prediction and overcoming the drawbacks of the aforementioned methods, a few works have also explored the potential of decoupling motion and appearance and building a two-stream pipeline. Using optical flow is an intuitive idea. Several previous works [27, 2, 52, 10] use built-in or off-the-shell systems to predict the optical flow from the past to future frames; they use the predicted optical flow to warp past frames into final results. The drawbacks of this line of work are two-fold: i) time-consuming, especially for the warping procedure of high-resolution video sequences; ii) more importantly, the one-to-one relationship defined by the optical flow may not be applicable for some cases such as when one pixel or superpixel moves half of the pixel size, or when one pixel has impacts on several pixels in the next frames. Besides optical flow, pose [43] and keypoint [11] are also used to represent the motion of the objects in the scene for video prediction. However, this approach requires extra pose or keypoint detectors to process videos. For videos with multiple objects, more complex motions, and higher resolution, the efficiency of these extra modules cannot be guaranteed. Alternatively, MCNet [6] uses the difference between frames to represent motion information. It does not require extra modules, but using concatenation to reunite motion and appearance features is inefficient. + +Compared to the small number of two-stream video pre + +diction systems above, our MMVP has three advantages: i) its motion matrix is able to describe the many-to-many relationship of the pixels or super-pixels, which makes MMVP much more flexible and reasonable for real-world data; ii) MMVP does not require an extra module to produce motion representation; and iii) the reunion of motion and appearance features is more intuitive and interpretable than the approaches used in previous works. This paper will demonstrate how MMVP makes a more capable and compact video prediction framework. + +# 3. Motion-Matrix-based Video Prediction + +# 3.1. Framework Overview + +Given a video sequence $\mathcal{I} = \{I_t\}_{t=1}^T$ , where $I_t$ denotes the $t$ th frame, usually in the RGB format, MMVP estimates the future $T'$ frames $\widehat{I_{T+1}}$ to $\widehat{I_{T+T'}}$ from $I_1$ to $I_T$ . In comparison to the known frame set $\mathcal{I}$ , we denote the estimated frame set as $\mathcal{I}' = \{I_t'\}_{t=T+1}^{T+T'}$ . The training of the framework is solely supervised by mean-squared error (MSE) loss. MMVP consists of three steps as follows: + +Step 1: Spatial feature extraction. We use an RRDBs [44] based network architecture to model an image encoding function $\Omega$ , defined in eq. 1. This image encoder embeds each frame $I_{i}, i \in \{1,2,\dots,T\}$ in a down-sample hidden space separately and outputs their corresponding hidden features $f_{i}$ . In MMVP, besides the image encoder, we have an extra filter block that models a filtering function $\Theta$ defined in eq. 2. It takes $f_{i}$ as the input and aims to generate $g_{i}$ . As the module name indicates, the filter block aims to filter out motion-irrelevant features of $f_{i}$ for motion matrix construction. We will introduce the details in Sec. 3.2. + +Step 2: Motion matrix construction and prediction. MMVP generates a set of motion matrices $\{\mathbf{M}_{i,i + 1}\} ,i\in$ $\{1,2,\dots,T - 1\}$ for every two consecutive frames based on their feature pairs $\{g_i,g_{i + 1}\}$ . Then, a matrix predicting function $\Phi$ defined in eq. 4 takes $\{\mathbf{M}_{i,i + 1}\}$ as the input and predicts future matrices $\{\widehat{\mathbf{M}_{T,T + j}}\} ,j\in \{T,\dots,T + T'\}$ . Sec. 3.3 will elaborate on the definition and construction procedures of the motion matrices, and Sec. 3.4 will demonstrate the inner structure of the matrix predictor. + +Step 3: Future composing and decoding. Using the output of steps 1 and 2, MMVP composes the unknown information for future frames. Then, a future decoding module takes the composed features as the input and outputs the final prediction. We will introduce the feature composition procedure in Sec. 3.5 and the future decoding module in Sec. 3.6. + +# 3.2. Spatial Feature Extraction + +Spatial feature extraction involves two components of the MMVP framework: image encoder, and filter block. + +The image encoder $\Omega$ in MMVP encodes every $I_{i}$ from the input data sequence to their corresponding features $f_{i}$ individually. The filter block $\Theta$ subsequently processes $f_{i}$ and makes it ready for the construction of a motion matrix. Formally, + +$$ +f _ {i} = \Omega \left(I _ {i}\right), \tag {1} +$$ + +$$ +g _ {i} = \Theta (f _ {i}), \tag {2} +$$ + +where $i \in \{1, 2, \dots, T\}$ . We use a convolutional network with residual in residual dense blocks (RRDBs) [44] to implement the image encoder, and we use a two-layer convolutional network to implement the filter block. See the detailed network architecture in Appendix. + +Next, the output features of the image encoder will take participate in the future feature composition, while the output of the filter block is only used for motion matrices construction. The existence of the filter block helps the model to filter out irrelevant features from the image encoder output and allows the construction of motion matrices to focus more on motion-related features. See Table 2 for the ablation study about the filter block. + +# 3.3. Motion Matrix Construction + +Given the output of the filter block $g_{i} \in \mathbb{R}^{\frac{H}{S} \times \frac{W}{S}}$ , $i \in \{1,2,\dots,T\}$ , we denote the feature patch at $(h,w)$ , $w \in \{0,1,2,\frac{W}{S} - 1\}$ , $h \in \{0,1,2,\frac{H}{S} - 1\}$ as $g_{i}^{h,w}$ , where $H$ and $W$ are the input images' height and width, and $S$ is the downsampling ratio to the original image; thus $\frac{H}{S}$ and $\frac{W}{S}$ are respectively the feature map's height and width. + +For two consecutive frames' feature $\{g_i, g_{i+1}\}$ , we calculate the cosine similarity for each and every pair of feature patches to construct a 4D motion matrix $\mathbf{M}_{i,i+1} \in \mathbb{R}^{\frac{H}{S} \times \frac{W}{S} \times \frac{H}{S} \times \frac{W}{S}}$ . We denote the element of the matrix $\mathbf{M}_{i,i+1}$ at $(h_i, w_i, h_{i+1}, w_{i+1})$ as $\mathbf{M}_{i,i+1}^{h_i, w_i, h_{i+1}, w_{i+1}}$ , and let + +$$ +\mathbf {M} _ {i, i + 1} ^ {h _ {i}, w _ {i}, h _ {i + 1}, w _ {i + 1}} = D _ {c} \left(g _ {i} ^ {h _ {i}, w _ {i}}, g _ {i + 1} ^ {h _ {i + 1}, w _ {i + 1}}\right). \tag {3} +$$ + +In the equation, $D_{c}$ is the cosine similarity, $g_{i}^{h_{i},w_{i}}$ is the feature patch of frame $i$ with the index of $(h_i,w_i)$ , and $g_{i + 1}^{h_{i + 1},w_{i + 1}}$ is the feature patch of frame $i + 1$ with the index of $(h_{i + 1},w_{i + 1})$ . With a feature patch at $(h_i,w_i)$ of $g_{i}$ as an + +example, the matrix $\mathbf{M}_{i,i + 1}^{h_i,w_i}\in \mathbb{R}^{H\times W}$ can be regarded as a heatmap that reflects how much impact $g_{i}^{h_{i},w_{i}}$ has on $g_{i + 1}$ , or more intuitively, the motion tendency of $g_{i}^{h_{i},w_{i}}$ (see Figure 5 for illustration). It is similar to the definition of optical flow [17], which determines the movement of a pixel or superpixel. The difference between optical flow and motion matrix is that motion matrix does not strictly define a one-to-one relationship between the pixels or superpixels of the current frame and those of the next frame. It is a more practical assumption in the video prediction task that one current feature patch may influence several future feature patches. + +# 3.4. Matrix Prediction + +Given the motion matrices of the past $T$ frames $\{\mathbf{M}_{1,2},\mathbf{M}_{2,3},\dots,\mathbf{M}_{T - 1,T}\}$ , the matrix predictor $\Psi$ predicts the future matrices $\{\mathbf{M}_{T,T + 1},\mathbf{M}_{T,T + 2},\dots,\mathbf{M}_{T,T'}\}$ . Instead of predicting the motion matrices between the consecutive frames, we predict the ones between the last observed frame $I_{T}$ and every future frame $I_{T + j},j\in \{1,2,\dots,T'\}$ , as + +$$ +\left\{\widehat {\mathbf {M} _ {T , T + j} ^ {w , h}} \right\} = \Psi \left(\left\{\mathbf {M} _ {i, i + 1} ^ {w, h} \right\}\right), \forall i \in \{1, 2, \dots , T - 1 \}, \tag {4} +$$ + +where $\mathbf{M}_{i,i+1}^{w,h} \in \mathbb{R}^{H \times W}$ , $w \in \{1,2,\dots,\frac{W}{S}\}$ and $h \in \{1,2,\dots,\frac{H}{S}\}$ . This design aims to reduce the accumulative error during feature composition and is validated by the long-term prediction setting shown in Table 3. Since for this work, we focus on testing the function and performance of the MMVP framework, we report the use of a simple $3D$ fully convolutional architecture to implement $\Psi$ . Fellow researchers can choose to easily replace the implementation of $\Psi$ with more advanced temporal modules if they wish to pursue better performances. + +![](images/da450c0279acec735040303e38e74079bf62a9f0b9190bdd1a3335f3cc4741c6.jpg) +Figure 4: All scales of image features and the original frames can join the future composition with predicted motion matrices through pixel unshuffle and shuffle operations. + +# 3.5. Multi-scale Future Composition + +The future composition step generates information for the future frames using the observed information and the motion matrices. It is formulated as + +$$ +\widehat {\mathcal {X} _ {T + j}} = \sum_ {i = 1} ^ {T} \left(\mathcal {X} _ {i} \times \prod_ {n = i} ^ {T - 1} \mathbf {M} _ {n, n + 1} \times \widehat {\mathbf {M} _ {T , T + j}}\right). \tag {5} +$$ + +As the equation indicates, instead of only using the information of the last observed frame, we use all observed information for future composition and lower the weight of earlier frames through repeated multiplication of the motion matrices. The $\mathcal{X}$ in the equation represents the observed information of the past frames. The information can be the output features of the image encoder with different scales $f_{i} \in \mathbb{R}^{H^{s} \times W^{s} \times C}$ , where $C$ is the feature length; the information can also be the observed frames $I_{i} \in \mathbb{R}^{H \times W \times 3}$ . Since the motion matrices are constructed from a certain scale of image features, there will be incompatibilities between the matrices and some features. To enable matrix multiplication between the motion matrices and the observed features (at any scales) or images, we borrow the pixel unshuffle and shuffle operations from [39]. The pixel unshuffle operation reshapes features or images into the identical scale as the motion matrices for matrix multiplication. Afterward, the pixel shuffle operation reshapes the results of the matrix multiplication back to the original scales of the features or images. See Figure 4 for demonstration. This whole process involves little information loss. In Table 6, we examine the multi-scale feature composition design. We find out that in general, the system achieves better performance when more scales of features take part in the feature composition. + +# 3.6. Future Decoding + +The future decoding procedure is used for aggregating and processing the composed features to formulate the final output. Since in the feature composition procedure, all scales of features are able to compose their corresponding scales of features for future frames, we adopt the decoder structure of UNet [37] with RRDB blocks [44] in the end to implement MMVP's image decoder. This design allows the composed features from all scales of image features, as well as the original images, to contribute to the final output. We use MSE loss to supervise the framework training. + +# 4. Experiment + +In this section, we evaluate MMVP quantitatively and qualitatively against existing state-of-the-art methods on various publicly available datasets. In addition, we analyze MMVP through a set of ablation studies on the UCF Sports dataset to better illustrate our design logic. + +# 4.1. Datasets + +We briefly review three widely used datasets and their configurations for MMVP evaluation. + +Table 1: Experiment settings for each dataset. + +
DatasetResolutionTrainTest
UCF Sports512 × 5124 → 14 → 6
KTH128 × 12810 → 20 or 4010 → 20 or 40
Moving MNIST64 × 6410 → 1010 → 10
+ +UCF Sports [36] contains 150 video sequences collected from various sports scenes with 10 different action types including running, kicking, and diving. It is regarded as a challenging dataset given its low frame rate (10 fps), high resolution $(480 \times 720)$ , and complex motion patterns. The video sequences in this dataset contain both rapid foreground (e.g. athletes) and background movements (e.g. the camera motion). We perform two different training/validation splits of this dataset, splits from STRPM [5] and our own splits, to facilitate different evaluation purposes. We use the STRPM splits for performance comparison with other methods (Table 4). In STRPM, long video sequences are cut into several short clips; for a particular sequence, some of its clips may be put into the training split, and others into the validation split. To avoid the appearance features of certain sequences in the validation set to be exposed in the training set, and to thoroughly evaluate MMVP's capability of video prediction, we generate our own splits for UCF Sports, which choose $90\%$ of the video sequences from each action type to form the training samples, and the rest $10\%$ to form the validation samples. + +Notably, within the same validation set, the difficulty level of different samples varies a lot. Some easier video clips contain static backgrounds and slow-moving objects, while others are more difficult for involving drastic camera movement and/or fast-moving objects. To better understand the model's prediction ability in different scenarios, we apply certain thresholds of the structural similarity index measure (SSIM) between the last observed frame and the first future frame to divide the UCF Sports validation set into three subsets: the easy $(\mathrm{SSIM} \leq 0.9)$ , intermediate $(0.6 \leq \mathrm{SSIM} < 0.9)$ , and hard subsets $(\mathrm{SSIM} < 0.6)$ , which respectively take up $66\%$ , $26\%$ , and $8\%$ of the full set. + +We use our own UCF Sports splits in the ablation studies (Sec. 4.3). For comparisons, we also train and test STIP [4] (extension of STRPM [5]) and SimVP [12] on our own UCF Sports splits; see Table 6. + +KTH [38] contains videos of 25 individuals performing six types of actions, i.e., walking, jogging, running, boxing, hand-waving, and hand-clapping. Following previous works [43, 46, 12], we use persons 1-16 for training and persons 17-25 for validation. The videos in KTH are in grayscale, but the challenging part of this dataset is its ex + +periment setting, which requires the system to output 20 or 40 frames given only 10 past frames. + +Moving MNIST [41] is a synthetic dataset. Each sequence in the dataset consists of two digits moving independently within the $64 \times 64$ grid and bouncing off the boundary. During the training time, by assigning different initial locations and velocities to each digit, one can generate an infinite number of sequences, and train the system to predict the future 10 frames from the previous 10 frames. For fair comparisons, we use the pre-generated 10000 sequences[12] for validation. + +# 4.2. Metrics + +We use the peak signal-to-noise ratio (PSNR) and structural similarity index measure (SSIM) to evaluate the image quality of the predicted frames. We use the implementation of PSNR and SSIM from the package scikit-learn [34]. For the UCF Sports dataset, we use Learned Perceptual Image Patch Similarity (LPIPS) [58] for better comparison with existing methods. LPIPS represents the perceptual quality of the predicted frames. It measures the feature distance of corresponding image patches between the predicted frames and the ground truth. Following the setting of these previous works, in the experiments on Moving MNIST, we use the sum of the mean squared error (MSE) from the entire frame to evaluate the image quality. + +# 4.3. Ablation Study + +We conduct the ablation study of future composition (Table 6), filter block (3rd and 4th rows of Table 2), and hyperparameters for both the image encoder/decoder and the matrix predictor (1st, 2nd, and 4th rows of Table 2) on our splits of the UCF Sports dataset. + +We first examine how the number of feature scales for feature composition impacts the results. Since we use the UNet structure with three times downsampling/upsampling operations to encode, we have four different scales of features for composition. For UCF Sports, the scales are $1, \frac{1}{2}, \frac{1}{8}, \frac{1}{16}$ . The motion matrices are constructed using features of $\frac{1}{8}$ scale. From Table 6 3rd to 5th rows, we observe consistent performance boosts on all metrics and subsets when we involve more scales of features for composition. We then test if using images for feature composition also boosts performance. By comparing the 5th and 6th rows of Table 6, we can still see an increasing pattern. However, since the scale of the image is identical to the largest scale of the features, to avoid redundancy and possible conflicts, we remove the features of the largest scale and produce the results of the last row in Table 6. We then see a comparable result to the one that uses all scales of features as well as the image. We adopt the model setting of the last row for the rest of the experiments. + +As mentioned in Sec. 3.2, we do not directly use the out + +put of the image encoder to construct the motion matrices. Instead, we add a filter block to filter out irrelevant features and help the motion matrices focus more on describing the temporal similarity regarding the motion-related features. Table 2 shows that the model with the filter block generally achieves better results on the UCF Sports validation set. + +Table 2: Ablation study on UCF Sports with LPIPS metrics (the lower the better), including the feature length of image and motion, and the usage of the filter block (F-Block). + +
ImgMotionF-BlockFullEasyIntermediateHardParam #
164✓0.11840.05920.18110.41680.70M
168✓0.11750.06000.17680.41220.71M
328×0.11240.05740.17290.38192.57M
328✓0.10620.05800.15690.35102.79M
STIPHR [4]0.16260.10660.22710.445018.05M
SimVP [12]0.13260.05840.19510.56003.47M
+ +Furthermore, Table 2 also shows an ablation study on the feature length of the appearance-related modules (image encoder and decoder) and the motion-related module (matrix predictor). We define the configuration of the second row as the MMVP-mini for Figure 1. + +# 4.4. Motion Matrix Visualization + +In Figure 5, we visualize the predicted motion matrices for certain selected feature patches. In all the demonstrated samples, the many-to-many relationships described by the predicted motion matrices are able to accurately capture the feature patches moving tendency. They show that the motion matrix can describe a wide range of motion patterns and scenarios, including multiple objects (1st sample of UCF Sports), the single person moving (KTH), multiple persons moving and camera moving (2nd sample of UCF Sports), and synthesized motions (Moving MNIST). + +# 4.5. Comparison with SOTA Methods + +We compare MMVP with existing SOTA methods on three popular datasets: UCF Sports (STRPM [5] splits, Table 4), KTH (Table 3), and Moving MNIST (Table 5). + +On the UCF Sports dataset, we observe large performance gains by MMVP compared to other methods. As mentioned above, the motion patterns in UCF Sports are the most complex of the three datasets due to many difficult cases, e.g., fast movement, camera moving, and motion blur. But the two-stream design of MMVP has shown its ability in such complex scenarios. Meanwhile, the video resolution of UCF Sports is also the highest among the three datasets. Most existing methods in Table 4 are inherently not designed for high-resolution videos, which requires larger network capacities to maintain appearance information. Although STRPM [5] and STIP [4] proposed residual temporal modules designed for high-resolution videos and they could largely surpass previous methods on both + +![](images/a667b0af9fb6c4ae95d91afbddb433ddaa4930524be4a12a5761ee817292b6a6.jpg) +Figure 5: Predicted motion matrix visualization. We highlight the selected feature patch(es) at $(h,w)$ in the last observed frame $I_{T}$ in red and visualize their corresponding predicted motion matrices $\mathbf{M}_{T,T + 1}^{h,w}\in \mathbb{R}^{H\times W}$ overlaying with the first future frame $I_{T + 1}$ . A brighter color indicates a higher predicted value. We select two samples for each dataset. From left to right, samples originate in the validation set of UCF Sports, KTH, and Moving MNIST. + +metrics, the appearance information loss in their methods is still unavoidable. MMVP, nevertheless, allows the image and multi-scale features to reach the decoder through a feature composing procedure, successfully minimizes the information loss, and achieves the best performance among all methods across all metrics. MMVP's success on the UCF Sports dataset validates its readiness for real-world applications, and its scalability for high-resolution videos. + +Another notable result is MMVP's ability in long-term information preservation; see Table 3. Despite having lower video resolutions and less complex motion patterns than UCF Sports, KTH as a real-world dataset still presents a difficulty as it requires systems to do long-term prediction given short-term observations. On the KTH dataset, MMVP achieves the #1 performance on SSIM metrics for both experiment settings with a small performance gap (27.54 to 26.35) in PSNR between the two settings. This is contributed by the design that the matrix predictor of MMVP predicts the temporal similarity matrices between the future frames and the last observed frame instead of their predecessors. Then, every predicted frame is composed of valid observed information. It reduces accumulated errors and ensures good performance for long-term prediction. + +Compared to the performance gains on UCF Sports, MMVP does not show much advantage on the Moving MNIST dataset. One speculation is that with video prediction research advancing, the problem of two-digits Moving MNIST with low resolution $(64\times 64)$ is nearly solved. With sufficient training time [12], current video prediction systems may all be able to achieve promising results. To further promote the growth of this field, researchers can consider more challenging datasets and experiment settings. + +Table 3: Performance comparison on the KTH dataset + +
MethodKTH10 → 20KTH10 → 40
SSIM ↑PSNR ↑SSIM ↑PSNR ↑
MCnet (ICLR2017) [43]0.80425.950.7323.89
ConvLSTM (NeurIPS2015) [40]0.71223.580.63922.85
SAVP (arXiv2018) [25]0.74625.380.70123.97
VPN (PMLR2017) [23]0.74623.76--
DFN (NeurIPS2016) [20]0.79427.260.65223.01
fRNN (ECCV2018) [32]0.77126.120.67823.77
Znet (ICME2019) [56]0.81727.58--
SV2Pi (ICLR2018) [1]0.82627.560.77825.92
SV2Pv (ICLR2018) [1]0.83827.790.78926.12
PredRNN (NeurIPS2017) [47]0.83927.550.70324.16
VarNet (IROS2018) [22]0.84328.480.73925.37
SVAP-VAE (arXiv2018) [25]0.85227.770.81126.18
PredRNN++ (ICML2018) [45]0.86528.470.74125.21
MSNET (BMVC2019) [26]0.87627.08--
E3d-LSTM (ICLR2019) [46]0.87929.310.81027.24
STMFANet (CVPR2020) [21]0.89329.850.85127.56
MMVP (ours)0.90627.540.88826.35
+ +Moreover, we analyze MMVP's performance on data of different difficulty levels using our own split of the UCF Sports dataset. We define the difficulty of a video using the SSIM between the last observed frame and the first frame to be predicted. This is because a lower SSIM indicates a larger difference between the two frames, and less possibility for a system to take the shortcut by using the residual information from past frames and not actually predicting the motion. Table 6 shows the quantitative evaluation compared with SimVP [12] and STIP [4]: as the difficulty level of the validation subset increases, the performance gap between MMVP and other methods also increases. + +Besides quantitative evaluation, we also showcase several qualitative visualizations in Figure 6 and compare them + +![](images/9dce96e9a3b87470096ffbe40c7ea4195192d63185d3bba2c3c3bd637000870b.jpg) +Figure 6: Qualitative results on our own splits of the UCF Sports dataset. + +Table 4: Performance comparison on UCF Sports STRPM split + +
Methodt=5t=10
PSNR↑LPIPS×100↓PSNR↑LPIPS×100↓
ConvLSTM (NeurIPS2015) [40]26.4332.2017.8058.78
BeyondMSE (ICLR2016) [30]26.4229.0118.4655.28
PredRNN (NeurIPS2017) [47]27.1728.1519.6555.34
PredRNN++ (ICML2018) [45]27.2626.8019.6756.79
SAVP (arXiv2018) [25]27.3525.4519.9049.91
SV2P (ICLR2018) [1]27.4425.8919.9751.33
E3D-LSTM (ICLR2019) [46]27.9825.1320.3347.76
CycleGAN (CVPR2019) [24]27.9922.9519.9944.93
CrevNet (ICLR2020) [55]28.2323.8720.3348.15
MotionRNN (CVPR2021) [51]27.6724.2320.0149.20
STRPM (CVPR2022) [5]28.5420.6920.5941.11
STIP (arXiv2022) [4]30.7512.7321.8339.67
DMVFN (CVPR2023) [19]30.0510.2422.6722.50
MMVP (Ours)31.687.8823.2522.24
+ +Table 5: Comparisons on Moving MNIST + +
MethodMSESSIM
ConvLSTM (NIPS 2015) [40]103.30.707
PredRNN (NIPS 2017) [47]56.80.867
PredRNN-V2 (Arxiv 2021) [48]48.40.891
CausalLSTM (ICML 2018) [45]46.50.898
MIM (CVPR 2019) [49]44.20.910
E3D-LSTM (ICLR 2018) [46]41.30.920
PhyDNet (CVPR 2020) [14]24.40.947
CrevNet (ICLR 2020) [55]22.30.949
SimVP (CVPR 2022) [12]23.80.948
MMVP(ours)22.20.952
+ +Table 6: Ablation study on sources for future composition and the comparison with other SOTA methods on UCF Sports. + +
MethodComposition sourceFull setEasy (SSIM ≥ 0.9)Intermediate (0.6 ≤ SSIM < 0.9)Hard (SSIM < 0.6)Param#
Img11/21/81/16SSIM ↑PSNR ↑LPIPS ↓SSIM ↑PSNR ↑LPIPS ↓SSIM ↑PSNR ↑LPIPS ↓SSIM ↑PSNR ↑LPIPS ↓
STIPHR [4]-0.881728.170.16260.949130.650.10660.835123.970.22710.467315.970.445018.05M
SimVP [12]-0.918929.970.13260.966432.870.05840.884525.790.19510.626718.990.56003.47M
MMVP×××✓✓0.900028.310.18740.937530.430.13420.875925.360.23040.659319.900.49922.75M
××✓✓✓0.928430.140.11150.966732.790.06030.893726.110.16930.715920.710.35702.79M
×✓✓✓✓0.929630.220.10640.966932.870.05760.896526.260.15710.719920.760.35552.80M
✓✓✓✓✓0.929630.290.10510.967532.990.05670.895826.220.15540.717520.760.35172.80M
✓×✓✓✓0.930030.350.10620.967433.050.05800.897026.290.15690.720320.840.35102.79M
+ +with SimVP [12] which achieved the second-best performance on our splits of the UCF Sports dataset. We especially select four samples in the hard and intermediate subsets for visualization. The first sample in Figure 6 shows a far-away object with long-distance movement. This is caused by the low fps of the dataset. MMVP accurately captures the displacement of the object while not losing the color and shape of the object. The challenge of the second sample in Figure 6 is also typical to UFC Sports, + +i.e. fast movement with motion blur. MMVP is able to recover the correct shape of the athletes' feet even if they are blurred in the observed frames. The third and fourth samples both show a fast camera movement, with and without large foreground movements. Camera moving with complex backgrounds is extremely difficult for video prediction. Even SimVP, which generated high-quality images for most of the datasets, barely captured the camera movements in these two samples and caused drastic blurs. Benefiting from + +its appearance-agnostic motion prediction module, MMVP achieved impressive performance in such cases. + +# 5. Discussion + +From Table 2 and Table 6 in Sec. 4, we observe that the proposed MMVP framework can always achieve better or comparable performance with significantly fewer parameters compared to the other SOTA methods. To better understand the high efficiency of MMVP, we break down a video prediction system into three components: i) content encoder, which encodes the image sequences; ii) prediction-related modules, which take charge of predicting features for future frames based on the output of the content encoder; iii) content decoder, which decodes the output of the predicted features output by the prediction-related modules. Then we examine the model size for each component in three video prediction systems: STIP [4], SimVP [12], and the proposed MMVP (configurations follow the second row and the fourth row in Table 2); see Table 7. + +In Table 7, prediction-related modules in STIP [4] and SimVP [12] handle both motion and appearance features. However, in MMVP, prediction-related modules specifically handle only the motion features, leaving all appearance features to the content encoder and decoder. The most noticeable fact from Table 7 is that in STIP [4] and SimVP [12], the prediction-related modules take majority of the model parameters (the ratios are $99.7\%$ and $99.4\%$ respectively). In contrast, motion-related modules in MMVP only take $14.5\%$ and $15.9\%$ of the parameters. This fact supports our argument in Sec. 1 that decoupling motion prediction and appearance maintenance effectively avoid the cumbersome structures of the prediction modules and largely improve the prediction efficiency. Another observation is that despite the small size, the prediction-related modules in MMVP can still support high-quality motion prediction. This validates the efficiency of the motion matrices when describing the motion information, which results in a lightweight design of the prediction module. + +Table 7: Model size breakdown. The numerical values are the number of parameters taken by each component in the video prediction systems. + +
MethodContent EncoderPrediction ModulesContent DecoderTotal
STIPHR [4]29.86K17994.8K29.54K18054.2K
SimVP [12]7.5k3447.1K11.7K3466.3K
MMVP-mini369.4K113.2K228.3K710.9K
MMVP1472.2K404.9K911.9K2789.0K
+ +# 6. Conclusion + +The proposed Motion-Matrix-based Video Prediction framework (MMVP) is an end-to-end trainable two-stream + +pipeline. MMVP uses motion matrices to represent appearance-agnostic motion patterns. As the sole input of the motion prediction module in MMVP, the motion matrix can i) describe the many-to-many relationships between feature patches without training for extra modules; ii) intuitively compose future features with multi-scale image features through matrix multiplication. It helps the motion prediction become more focused, and efficiently reduces the information loss in appearance. Extensive experiments demonstrate the superiority of MMVP compared to existing SOTA methods in both the model size and performance. + +# References + +[1] Mohammad Babaeizadeh, Chelsea Finn, Dumitru Erhan, Roy H Campbell, and Sergey Levine. Stochastic variational video prediction. arXiv preprint arXiv:1710.11252, 2017. 7, 8 +[2] Xinzhu Bei, Yanchao Yang, and Stefano Soatto. Learning semantic-aware dynamics for video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 902-912, 2021. 2, 3 +[3] Po-Rong Chang and Jen-Tsung Hu. Optimal nonlinear adaptive prediction and modeling ofmpeg video in atm networks using pipelined recurrent neural networks. IEEE Journal on Selected Areas in Communications, 15(6):1087-1100, 1997. 1 +[4] Zheng Chang, Xinfeng Zhang, Shanshe Wang, Siwei Ma, and Wen Gao. Stip: A spatiotemporal information-preserving and perception-augmented model for high-resolution video prediction. arXiv preprint arXiv:2206.04381, 2022. 1, 2, 3, 5, 6, 7, 8, 9 +[5] Zheng Chang, Xinfeng Zhang, Shanshe Wang, Siwei Ma, and Wen Gao. Strpm: A spatiotemporal residual predictive model for high-resolution video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13946-13955, 2022. 1, 2, 3, 5, 6, 8 +[6] Emily L Denton et al. Unsupervised learning of disentangled representations from video. Advances in neural information processing systems, 30, 2017. 2, 3 +[7] Duarte Duque, Henrique Santos, and Paulo Cortez. Prediction of abnormal behaviors for intelligent video surveillance systems. In 2007 IEEE Symposium on Computational Intelligence and Data Mining, pages 362-367. IEEE, 2007. 1 +[8] Frederik Ebert, Chelsea Finn, Sudeep Dasari, Annie Xie, Alex Lee, and Sergey Levine. Visual foresight: Model-based deep reinforcement learning for vision-based robotic control. arXiv preprint arXiv:1812.00568, 2018. 1 +[9] Chelsea Finn and Sergey Levine. Deep visual foresight for planning robot motion. In 2017 IEEE International Conference on Robotics and Automation (ICRA), pages 2786-2793. IEEE, 2017. 1 +[10] Hang Gao, Huazhe Xu, Qi-Zhi Cai, Ruth Wang, Fisher Yu, and Trevor Darrell. Disentangling propagation and generation for video prediction. In Proceedings of the IEEE/CVF + +international conference on computer vision, pages 9006-9015, 2019. 2, 3 +[11] Xiaojie Gao, Yueming Jin, Qi Dou, Chi-Wing Fu, and Pheng-Ann Heng. Accurate grid keypoint learning for efficient video prediction. In 2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages 5908–5915. IEEE, 2021. 2, 3 +[12] Zhangyang Gao, Cheng Tan, Lirong Wu, and Stan Z Li. Simvp: Simpler yet better video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3170-3180, 2022. 1, 2, 5, 6, 7, 8, 9 +[13] Bernd Girod. The efficiency of motion-compensating prediction for hybrid coding of video sequences. IEEE Journal on selected areas in communications, 5(7):1140-1154, 1987. 1 +[14] Vincent Le Guen and Nicolas Thome. Disentangling physical dynamics from unknown factors for unsupervised video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11474-11484, 2020. 8 +[15] Agrim Gupta, Stephen Tian, Yunzhi Zhang, Jiajun Wu, Roberto Martín-Martín, and Li Fei-Fei. Maskvit: Masked visual pre-training for video prediction. arXiv preprint arXiv:2206.11894, 2022.3 +[16] Noriaki Hirose, Fei Xia, Roberto Martín-Martín, Amir Sadeghian, and Silvio Savarese. Deep visual mpc-policy learning for navigation. IEEE Robotics and Automation Letters, 4(4):3184-3191, 2019. 1 +[17] Berthold KP Horn and Brian G Schunck. Determining optical flow. Artificial intelligence, 17(1-3):185–203, 1981. 4 +[18] Jun-Ting Hsieh, Bingbin Liu, De-An Huang, Li F Fei-Fei, and Juan Carlos Niebles. Learning to decompose and disentangle representations for video prediction. Advances in neural information processing systems, 31, 2018. 3 +[19] Xiaotao Hu, Zhewei Huang, Ailin Huang, Jun Xu, and Shuchang Zhou. A dynamic multi-scale voxel flow network for video prediction. arXiv preprint arXiv:2303.09875, 2023. 8 +[20] Xu Jia, Bert De Brabandere, Tinne Tuytelaars, and Luc V Gool. Dynamic filter networks. Advances in neural information processing systems, 29, 2016. 7 +[21] Beibei Jin, Yu Hu, Qiankun Tang, Jingyu Niu, Zhiping Shi, Yinhe Han, and Xiaowei Li. Exploring spatial-temporal multi-frequency analysis for high-fidelity and temporal-consistency video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4554-4563, 2020. 7 +[22] Beibei Jin, Yu Hu, Yiming Zeng, Qiankun Tang, Shice Liu, and Jing Ye. Varnet: Exploring variations for unsupervised video prediction. In 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages 5801-5806. IEEE, 2018. 7 +[23] Nal Kalchbrenner, Aäron Oord, Karen Simonyan, Ivo Danihelka, Oriol Vinyals, Alex Graves, and Koray Kavukcuoglu. Video pixel networks. In International Conference on Machine Learning, pages 1771-1779. PMLR, 2017. 3, 7 +[24] Yong-Hoon Kwon and Min-Gyu Park. Predicting future frames using retrospective cycle gan. In Proceedings of + +the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1811-1820, 2019. 8 +[25] Alex X Lee, Richard Zhang, Frederik Ebert, Pieter Abbeel, Chelsea Finn, and Sergey Levine. Stochastic adversarial video prediction. arXiv preprint arXiv:1804.01523, 2018. 7, 8 +[26] Jungbeom Lee, Jangho Lee, Sungmin Lee, and Sungroh Yoon. Mutual suppression network for video prediction using disentangled features. arXiv preprint arXiv:1804.04810, 2018. 7 +[27] Xiaodan Liang, Lisa Lee, Wei Dai, and Eric P Xing. Dual motion gan for future-flow embedded video prediction. In proceedings of the IEEE international conference on computer vision, pages 1744-1752, 2017. 2, 3 +[28] Jianping Lin, Dong Liu, Houqiang Li, and Feng Wu. M-lvc: Multiple frames prediction for learned video compression. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3546-3554, 2020. 1 +[29] Bowen Liu, Yu Chen, Shiyu Liu, and Hun-Seok Kim. Deep learning in latent space for video prediction and compression. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 701-710, 2021. 1 +[30] Michael Mathieu, Camille Couprie, and Yann LeCun. Deep multi-scale video prediction beyond mean square error. arXiv preprint arXiv:1511.05440, 2015. 8 +[31] Tomas Mikolov, Martin Karafiát, Lukas Burget, Jan Cernocký, and Sanjeev Khudanpur. Recurrent neural network based language model. In *Interspeech*, volume 2, pages 1045–1048. Makuhari, 2010. 1 +[32] Marc Oliu, Javier Selva, and Sergio Escalera. Folded recurrent neural networks for future video prediction. In Proceedings of the European Conference on Computer Vision (ECCV), pages 716-731, 2018. 7 +[33] Sergiu Oprea, Pablo Martinez-Gonzalez, Alberto Garcia-Garcia, John Alejandro Castro-Vargas, Sergio Orts-Escalano, Jose Garcia-Rodriguez, and Antonis Argyros. A review on deep learning techniques for video prediction. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(6):2806-2826, 2020. 2 +[34] F. Pedregosa, G. Varoquaux, A. Gramfort, V. Michel, B. Thirion, O. Grisel, M. Blondel, P. Prettenhofer, R. Weiss, V. Dubourg, J. Vanderplas, A. Passos, D. Cournaepau, M. Brucher, M. Perrot, and E. Duchesnay. Scikit-learn: Machine learning in Python. Journal of Machine Learning Research, 12:2825-2830, 2011. 6 +[35] Ruslan Rakhimov, Denis Volkhonskiy, Alexey Artemov, Denis Zorin, and Evgeny Burnaev. Latent video transformer. arXiv preprint arXiv:2006.10704, 2020. 3 +[36] Mikel D Rodriguez, Javed Ahmed, and Mubarak Shah. Action mach a spatio-temporal maximum average correlation height filter for action recognition. In 2008 IEEE conference on computer vision and pattern recognition, pages 1-8. IEEE, 2008. 2, 5 +[37] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image com + +puting and computer-assisted intervention, pages 234-241. Springer, 2015. 5 +[38] Christian Schuldt, Ivan Laptev, and Barbara Caputo. Recognizing human actions: a localsvm approach. In Proceedings of the 17th International Conference on Pattern Recognition, 2004.ICPR 2004., volume 3,pages 32-36.IEEE,2004.2,5 +[39] Wenzhe Shi, Jose Caballero, Ferenc Huszár, Johannes Totz, Andrew P Aitken, Rob Bishop, Daniel Rueckert, and Zehan Wang. Real-time single image and video super-resolution using an efficient sub-pixel convolutional neural network. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1874-1883, 2016. 5 +[40] Xingjian Shi, Zhourong Chen, Hao Wang, Dit-Yan Yeung, Wai-Kin Wong, and Wang-chun Woo. Convolutional LSTM network: A machine learning approach for precipitation nowcasting. Advances in neural information processing systems, 28, 2015. 3, 7, 8 +[41] Nitish Srivastava, Elman Mansimov, and Ruslan Salakhudinov. Unsupervised learning of video representations using lstms. In International conference on machine learning, pages 843-852. PMLR, 2015. 2, 6 +[42] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. 1, 3 +[43] Ruben Villegas, Jimei Yang, Seunghoon Hong, Xunyu Lin, and Honglak Lee. Decomposing motion and content for natural video sequence prediction. arXiv preprint arXiv:1706.08033, 2017. 2, 3, 5, 7 +[44] Xintao Wang, Ke Yu, Shixiang Wu, Jinjin Gu, Yihao Liu, Chao Dong, Yu Qiao, and Chen Change Loy. Esrgan: Enhanced super-resolution generative adversarial networks. In Proceedings of the European conference on computer vision (ECCV) workshops, pages 0–0, 2018. 3, 4, 5 +[45] Yunbo Wang, Zhifeng Gao, Mingsheng Long, Jianmin Wang, and S Yu Philip. Predrnn++: Towards a resolution of the deep-in-time dilemma in spatiotemporal predictive learning. In International Conference on Machine Learning, pages 5123-5132. PMLR, 2018. 1, 2, 3, 7, 8 +[46] Yunbo Wang, Lu Jiang, Ming-Hsuan Yang, Li-Jia Li, Mingsheng Long, and Li Fei-Fei. Eidetic 3d LSTM: A model for video prediction and beyond. In International conference on learning representations, 2018. 1, 2, 3, 5, 7, 8 +[47] Yunbo Wang, Mingsheng Long, Jianmin Wang, Zhifeng Gao, and Philip S Yu. Predrnn: Recurrent neural networks for predictive learning using spatiotemporal lstms. Advances in neural information processing systems, 30, 2017. 1, 2, 3, 7, 8 +[48] Yunbo Wang, Haixu Wu, Jianjin Zhang, Zhifeng Gao, Jian-min Wang, Philip Yu, and Mingsheng Long. Predrnn: A recurrent neural network for spatiotemporal predictive learning. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 8 +[49] Yunbo Wang, Jianjin Zhang, Hongyu Zhu, Mingsheng Long, Jianmin Wang, and Philip S Yu. Memory in memory: A predictive neural network for learning higher-order nonstationarity from spatiotemporal dynamics. In Proceedings + +of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9154-9162, 2019. 8 +[50] Dirk Weissenborn, Oscar Täckström, and Jakob Uszkoreit. Scaling autoregressive video models. arXiv preprint arXiv:1906.02634, 2019. 3 +[51] Haixu Wu, Zhiyu Yao, Jianmin Wang, and Mingsheng Long. Motionrnn: A flexible model for video prediction with spacetime-varying motions. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 15435-15444, 2021. 8 +[52] Yue Wu, Qiang Wen, and Qifeng Chen. Optimizing video prediction via video frame interpolation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 17814-17823, 2022. 2, 3 +[53] Ren Yang, Radu Timofte, and Luc Van Gool. Advancing learned video compression with in-loop frame prediction. IEEE Transactions on Circuits and Systems for Video Technology, 2022. 1 +[54] Wei Yu, Yichao Lu, Steve Easterbrook, and Sanja Fidler. Crevnet: Conditionally reversible video prediction. arXiv preprint arXiv:1910.11577, 2019. 2 +[55] Wei Yu, Yichao Lu, Steve Easterbrook, and Sanja Fidler. Efficient and information-preserving future frame prediction and beyond. 2020. 1, 8 +[56] Jianjin Zhang, Yunbo Wang, Mingsheng Long, Wang Jian-min, and S Yu Philip. Z-order recurrent neural networks for video prediction. In 2019 IEEE International Conference on Multimedia and Expo (ICME), pages 230-235. IEEE, 2019. 7 +[57] Qianqian Zhang, Guorui Feng, and Hanzhou Wu. Surveillance video anomaly detection via non-local u-net frame prediction. Multimedia Tools and Applications, 81(19):27073-27088, 2022. 1 +[58] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 586-595, 2018. 6 +[59] Xianguo Zhang, Tiejun Huang, Yonghong Tian, and Wen Gao. Background-modeling-based adaptive prediction for surveillance video coding. IEEE Transactions on Image Processing, 23(2):769-784, 2013. 1 \ No newline at end of file diff --git a/2023/MMVP_ Motion-Matrix-Based Video Prediction/images.zip b/2023/MMVP_ Motion-Matrix-Based Video Prediction/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..e83e5d628c8b8c390b93d4e1c01ac54d24bf6362 --- /dev/null +++ b/2023/MMVP_ Motion-Matrix-Based Video Prediction/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:50faef27385eba7792e1a65866a7d9c636dcaa6b4bd43b050114cdcede8c4dde +size 715621 diff --git a/2023/MMVP_ Motion-Matrix-Based Video Prediction/layout.json b/2023/MMVP_ Motion-Matrix-Based Video Prediction/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..1db1a08d10beb899e51a662848dc4a8d0ac6be64 --- /dev/null +++ b/2023/MMVP_ Motion-Matrix-Based Video Prediction/layout.json @@ -0,0 +1,9035 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 148, + 103, + 445, + 119 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 148, + 103, + 445, + 119 + ], + "spans": [ + { + "bbox": [ + 148, + 103, + 445, + 119 + ], + "type": "text", + "content": "MMVP: Motion-Matrix-based Video Prediction" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "spans": [ + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "text", + "content": "Yiqi Zhong" + }, + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "text", + "content": " Luming Liang" + }, + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "inline_equation", + "content": "^{2*}" + }, + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "text", + "content": " Ilya Zharkov" + }, + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "text", + "content": " Ulrich Neumann" + }, + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "text", + "content": "University of Southern California " + }, + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 129, + 141, + 467, + 171 + ], + "type": "text", + "content": "Microsoft" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 129, + 171, + 465, + 186 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 129, + 171, + 465, + 186 + ], + "spans": [ + { + "bbox": [ + 129, + 171, + 465, + 186 + ], + "type": "text", + "content": "1{yiqizhon,uneumann}@usc.edu 2{lulian,zharkov}@microsoft.com" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "spans": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 238, + 290, + 490 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 238, + 290, + 490 + ], + "spans": [ + { + "bbox": [ + 46, + 238, + 290, + 490 + ], + "type": "text", + "content": "A central challenge of video prediction lies where the system has to reason the objects' future motions from image frames while simultaneously maintaining the consistency of their appearances across frames. This work introduces an end-to-end trainable two-stream video prediction framework, Motion-Matrix-based Video Prediction (MMVP), to tackle this challenge. Unlike previous methods that usually handle motion prediction and appearance maintenance within the same set of modules, MMVP decouples motion and appearance information by constructing appearance-agnostic motion matrices. The motion matrices represent the temporal similarity of each and every pair of feature patches in the input frames, and are the sole input of the motion prediction module in MMVP. This design improves video prediction in both accuracy and efficiency, and reduces the model size. Results of extensive experiments demonstrate that MMVP outperforms state-of-the-art systems on public data sets by non-negligible large margins (" + }, + { + "bbox": [ + 46, + 238, + 290, + 490 + ], + "type": "inline_equation", + "content": "\\approx" + }, + { + "bbox": [ + 46, + 238, + 290, + 490 + ], + "type": "text", + "content": " 1 db in PSNR, UCF Sports) in significantly smaller model sizes (84% the size or smaller). Please refer to this link for the official code and the datasets used in this paper." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 512, + 128, + 525 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 512, + 128, + 525 + ], + "spans": [ + { + "bbox": [ + 47, + 512, + 128, + 525 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 532, + 288, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 532, + 288, + 676 + ], + "spans": [ + { + "bbox": [ + 46, + 532, + 288, + 676 + ], + "type": "text", + "content": "Video prediction aims at predicting future frames from limited past frames. It is a longstanding yet unsolved problem studied for decades [13, 3]. Advancing research in this area benefits various applications such as video compression [29, 53, 28], surveillance systems [57, 59, 7], and robotics [9, 16, 8]. The task can be essentially broken down into two sub-tasks: i) motion prediction and ii) frame synthesis. Each sub-task has its unique goal that cannot be simply accomplished by achieving the other one. For the sub-task of motion prediction, systems need to reason the future movements of objects/backgrounds by discovering the motion cues hidden in the past frames. Whereas for" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 213, + 546, + 275 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 213, + 546, + 275 + ], + "spans": [ + { + "bbox": [ + 306, + 213, + 546, + 275 + ], + "type": "text", + "content": "the sub-task of frame synthesis, systems need to maintain appearance features and generate future frames that keep appearance consistency. These separated goals make video prediction inherently much more difficult than the individual task of normal motion prediction or content synthesis." + } + ] + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 326, + 285, + 525, + 475 + ], + "blocks": [ + { + "bbox": [ + 326, + 285, + 525, + 475 + ], + "lines": [ + { + "bbox": [ + 326, + 285, + 525, + 475 + ], + "spans": [ + { + "bbox": [ + 326, + 285, + 525, + 475 + ], + "type": "image", + "image_path": "c745e68edda03c063b3ca4bf4e348a5632bef93014e68409d91f91f0e13dfdc7.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 478, + 547, + 540 + ], + "lines": [ + { + "bbox": [ + 304, + 478, + 547, + 540 + ], + "spans": [ + { + "bbox": [ + 304, + 478, + 547, + 540 + ], + "type": "text", + "content": "Figure 1: Performance comparison on UCF Sports with STIP [4] and SimVP [12]. The hard subset contains samples where SSIM between the last observed frame and the first future frame is smaller than 0.6, which indicates drastic motion patterns (data is from Tables 2 and 6)." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "type": "text", + "content": "Most existing works in video prediction are based on a single-stream pipeline that conducts motion prediction and appearance feature extraction for frame synthesis within the same set of modules. Their systems [47, 45, 46, 55, 5, 4] usually grow out of advanced network structures for sequential data analysis, such as recurrent neural networks (RNNs) [31] and transformers [42]. One shared characteristic of those methods is that they show excellent capabilities in capturing complex motion patterns but lower capabilities in appearance maintenance, yielding \"correct\" but not \"good\" synthesized frames. The reason behind this is that those methods usually contain complicated spatial-temporal feature extraction and state transition operations, which can cause unavoidable appearance information loss." + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 57, + 683, + 130, + 693 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 683, + 130, + 693 + ], + "spans": [ + { + "bbox": [ + 57, + 683, + 130, + 693 + ], + "type": "text", + "content": "*Equal contributions." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 59, + 693, + 263, + 703 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 693, + 263, + 703 + ], + "spans": [ + { + "bbox": [ + 59, + 693, + 263, + 703 + ], + "type": "text", + "content": "†The work is done during Yiqi Zhong's internship at Microsoft." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "type": "inline_equation", + "content": "\\ddagger" + }, + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "type": "text", + "content": " Corresponding authors." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "4273" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 70, + 68, + 542, + 205 + ], + "blocks": [ + { + "bbox": [ + 70, + 68, + 542, + 205 + ], + "lines": [ + { + "bbox": [ + 70, + 68, + 542, + 205 + ], + "spans": [ + { + "bbox": [ + 70, + 68, + 542, + 205 + ], + "type": "image", + "image_path": "eafe28ca599c68dc3be11a323c3d5ba4d42dce837b24bae62f4cadb44370bb84.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 209, + 547, + 235 + ], + "lines": [ + { + "bbox": [ + 46, + 209, + 547, + 235 + ], + "spans": [ + { + "bbox": [ + 46, + 209, + 547, + 235 + ], + "type": "text", + "content": "Figure 2: MMVP is a two-stream video prediction framework. It decouples motion prediction and appearance maintenance, and it reunites motion and appearance features through feature composition operation." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 249, + 289, + 392 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 249, + 289, + 392 + ], + "spans": [ + { + "bbox": [ + 46, + 249, + 289, + 392 + ], + "type": "text", + "content": "Researchers have proposed several solutions to mitigate appearance information loss; the most common approaches are introducing sophisticated appearance-aware state transition unit [5, 4, 54], or adding frequent feature shortcuts from previous frames [12, 46, 47, 45]. However, the former solution tends to build cumbersome models with a huge number of parameters; and for the latter solution, too much residual information from previous frames can cause a larger performance drop for hard cases such as videos with fast movements and/or moving cameras. Figure 1 shows the comparison between STIP [4] (an example of the former solution) and SimVP [12] (an example of the latter solution)." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 397, + 287, + 517 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 397, + 287, + 517 + ], + "spans": [ + { + "bbox": [ + 46, + 397, + 287, + 517 + ], + "type": "text", + "content": "To avoid running into possible trade-offs between motion and appearance in single-stream pipelines, a few works have explored two-stream pipelines [27, 2, 10, 43, 11], decoupling motion prediction and appearance maintenance. However, they either require auxiliary sub-networks such as optical flow estimator [27, 52] and key point detector [11] to generate motion representations, which complicates video prediction and reduces the generalizability of systems; or they do not provide an efficient solution to reunite the predicted motion and the appearance features [6, 43]." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 521, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 521, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 521, + 288, + 714 + ], + "type": "text", + "content": "With these gaps in current research, we introduce a novel two-stream, end-to-end trainable framework for video prediction: Motion-Matrix-based Video Prediction (MMVP) (see Figure 2 for the framework overview). As the name indicates, MMVP uses motion matrices as the decoupled motion representation of video frames. The motion matrix is a 4D matrix representing the image feature patches of consecutive frames (see Figure 3 I). As motion matrices are the sole input of the matrix predictor (i.e., the motion prediction module in MMVP), MMVP specifies the hidden motion information and makes the matrix predictor only focus on motion-related information. For the reunion of motion and appearance features, MMVP gets inspiration from the image autoencoder. It first embeds the past frames individually through an image encoder. Then it composes the embedding of the future frames using the predicted motion" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 249, + 545, + 296 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 249, + 545, + 296 + ], + "spans": [ + { + "bbox": [ + 304, + 249, + 545, + 296 + ], + "type": "text", + "content": "matrices output by the matrix predictor and the past frames' embeddings through matrix multiplication (see Figure 3 II). Then, an image decoder decodes the composed embeddings into the predicted future frames." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 297, + 546, + 525 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 297, + 546, + 525 + ], + "spans": [ + { + "bbox": [ + 304, + 297, + 546, + 525 + ], + "type": "text", + "content": "The advantage of MMVP is three-fold: (i) MMVP decouples motion and appearance by constructing motion matrices, requiring no extra construction modules; (ii) unlike optical flow that describes the one-to-one relationship between pixels, motion matrices describe the many-to-many relationship between feature patches, and are more flexible and applicable for real-world data; (iii) MMVP reunites the appearance and motion prediction results through matrix multiplication, which is interpretable and of little information loss. The advantages make MMVP a much more compact model with significantly fewer parameters yet still matching SOTA methods in performance. We validate MMVP on three datasets, UCF Sports [36], KTH [38], and MovingMNIST [41]. Experiments show that MMVP matches or surpasses SOTA methods on all three datasets across metrics. Specifically, compared to STIP [4], MMVP uses " + }, + { + "bbox": [ + 304, + 297, + 546, + 525 + ], + "type": "inline_equation", + "content": "84\\%" + }, + { + "bbox": [ + 304, + 297, + 546, + 525 + ], + "type": "text", + "content": " fewer parameters (18M vs. 2.8M) but achieves " + }, + { + "bbox": [ + 304, + 297, + 546, + 525 + ], + "type": "inline_equation", + "content": "38\\%" + }, + { + "bbox": [ + 304, + 297, + 546, + 525 + ], + "type": "text", + "content": " better performance in the LPIPS metric (12.73 vs. 7.88) on the UCF Sports dataset (Table 4)." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 536, + 398, + 550 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 536, + 398, + 550 + ], + "spans": [ + { + "bbox": [ + 306, + 536, + 398, + 550 + ], + "type": "text", + "content": "2. Related Works" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 557, + 545, + 629 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 557, + 545, + 629 + ], + "spans": [ + { + "bbox": [ + 304, + 557, + 545, + 629 + ], + "type": "text", + "content": "Good video prediction systems should not only accurately reason the future motions of the objects but also maintain their appearances and synthesize consistent future frames. As the video resolution has become increasingly higher today, researchers should additionally consider the scalability and efficiency of video prediction systems [33]." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "text", + "content": "Most video prediction works to date adopt a single-stream pipeline that grows out of advanced techniques in sequential data analysis. Those techniques usually contain sophisticated spatial-temporal feature extraction operations and state transitions, which result in appearance information loss. Thus, researchers tend to modify the techniques to let them attend more to appearance mainte" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "4274" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 75, + 88, + 286, + 171 + ], + "blocks": [ + { + "bbox": [ + 76, + 77, + 231, + 88 + ], + "lines": [ + { + "bbox": [ + 76, + 77, + 231, + 88 + ], + "spans": [ + { + "bbox": [ + 76, + 77, + 231, + 88 + ], + "type": "text", + "content": "I. Appearance-agnostic Motion Matrix M" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 75, + 88, + 286, + 171 + ], + "lines": [ + { + "bbox": [ + 75, + 88, + 286, + 171 + ], + "spans": [ + { + "bbox": [ + 75, + 88, + 286, + 171 + ], + "type": "image", + "image_path": "3871523fb7da684852f58c769c660e4fbf40bdde955559bd806b9fefc38611de.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 280, + 78, + 365, + 88 + ], + "lines": [ + { + "bbox": [ + 280, + 78, + 365, + 88 + ], + "spans": [ + { + "bbox": [ + 280, + 78, + 365, + 88 + ], + "type": "text", + "content": "II. Future Composition" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "lines": [ + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "spans": [ + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "text", + "content": "Figure 3: MMVP relies on the motion matrix " + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "inline_equation", + "content": "\\mathbf{M}" + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "inline_equation", + "content": "\\mathbf{M}" + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "text", + "content": " is an appearance-agnostic motion representation that measures the cosine similarity between the feature patches of two consecutive frames. Information of the past frames " + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "inline_equation", + "content": "\\{\\mathcal{X}_0,\\dots,\\mathcal{X}_T\\}" + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "text", + "content": " can compose the future information " + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "inline_equation", + "content": "\\{\\widehat{\\mathcal{X}}_{T + 1},\\dots,\\widehat{\\mathcal{X}_{T^{\\prime}}}\\}" + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "text", + "content": " through matrix multiplication " + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "inline_equation", + "content": "\\otimes" + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "inline_equation", + "content": "\\mathbf{M}" + }, + { + "bbox": [ + 45, + 171, + 547, + 210 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 285, + 90, + 541, + 167 + ], + "blocks": [ + { + "bbox": [ + 285, + 90, + 541, + 167 + ], + "lines": [ + { + "bbox": [ + 285, + 90, + 541, + 167 + ], + "spans": [ + { + "bbox": [ + 285, + 90, + 541, + 167 + ], + "type": "image", + "image_path": "525a8701d8f92d8a2bd93b2f6579f840546571e3ab82f27bcdea0a7ee7e13506.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 216, + 289, + 396 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 216, + 289, + 396 + ], + "spans": [ + { + "bbox": [ + 46, + 216, + 289, + 396 + ], + "type": "text", + "content": "nance [47, 40, 45, 5, 4, 46, 18]. Based on ConvLSTM [40], PredRNN [47] propose a novel memory state transition method between the recurrent nodes to help the appearance features from observations be delivered to the final prediction. E3D-LSTM [46] integrated 3D convolution operations to help emphasize the short-term appearance. CrevNet [23] uses a conditionally reversible network to preserve the information from the past frames. More recently, the progress in temporal modeling made by transformer-based methods [42] has drawn more attention. The field starts to see works that use transformers in video prediction tasks [15, 50, 35]. These works have a better information aggregation capability and less appearance information loss, but they usually have a huge number of parameters and lack scalability to higher-resolution videos." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 399, + 289, + 698 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 399, + 289, + 698 + ], + "spans": [ + { + "bbox": [ + 46, + 399, + 289, + 698 + ], + "type": "text", + "content": "Seeking an alternative solution to video prediction and overcoming the drawbacks of the aforementioned methods, a few works have also explored the potential of decoupling motion and appearance and building a two-stream pipeline. Using optical flow is an intuitive idea. Several previous works [27, 2, 52, 10] use built-in or off-the-shell systems to predict the optical flow from the past to future frames; they use the predicted optical flow to warp past frames into final results. The drawbacks of this line of work are two-fold: i) time-consuming, especially for the warping procedure of high-resolution video sequences; ii) more importantly, the one-to-one relationship defined by the optical flow may not be applicable for some cases such as when one pixel or superpixel moves half of the pixel size, or when one pixel has impacts on several pixels in the next frames. Besides optical flow, pose [43] and keypoint [11] are also used to represent the motion of the objects in the scene for video prediction. However, this approach requires extra pose or keypoint detectors to process videos. For videos with multiple objects, more complex motions, and higher resolution, the efficiency of these extra modules cannot be guaranteed. Alternatively, MCNet [6] uses the difference between frames to represent motion information. It does not require extra modules, but using concatenation to reunite motion and appearance features is inefficient." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 59, + 701, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 701, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 59, + 701, + 287, + 714 + ], + "type": "text", + "content": "Compared to the small number of two-stream video pre" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 216, + 547, + 337 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 216, + 547, + 337 + ], + "spans": [ + { + "bbox": [ + 304, + 216, + 547, + 337 + ], + "type": "text", + "content": "diction systems above, our MMVP has three advantages: i) its motion matrix is able to describe the many-to-many relationship of the pixels or super-pixels, which makes MMVP much more flexible and reasonable for real-world data; ii) MMVP does not require an extra module to produce motion representation; and iii) the reunion of motion and appearance features is more intuitive and interpretable than the approaches used in previous works. This paper will demonstrate how MMVP makes a more capable and compact video prediction framework." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 347, + 520, + 360 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 347, + 520, + 360 + ], + "spans": [ + { + "bbox": [ + 305, + 347, + 520, + 360 + ], + "type": "text", + "content": "3. Motion-Matrix-based Video Prediction" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 367, + 432, + 379 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 367, + 432, + 379 + ], + "spans": [ + { + "bbox": [ + 306, + 367, + 432, + 379 + ], + "type": "text", + "content": "3.1. Framework Overview" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "spans": [ + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "text", + "content": "Given a video sequence " + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "inline_equation", + "content": "\\mathcal{I} = \\{I_t\\}_{t=1}^T" + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "inline_equation", + "content": "I_t" + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "text", + "content": " denotes the " + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "text", + "content": "th frame, usually in the RGB format, MMVP estimates the future " + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "inline_equation", + "content": "T'" + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "text", + "content": " frames " + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "inline_equation", + "content": "\\widehat{I_{T+1}}" + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "inline_equation", + "content": "\\widehat{I_{T+T'}}" + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "inline_equation", + "content": "I_1" + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "inline_equation", + "content": "I_T" + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "text", + "content": ". In comparison to the known frame set " + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "inline_equation", + "content": "\\mathcal{I}" + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "text", + "content": ", we denote the estimated frame set as " + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "inline_equation", + "content": "\\mathcal{I}' = \\{I_t'\\}_{t=T+1}^{T+T'}" + }, + { + "bbox": [ + 304, + 384, + 545, + 472 + ], + "type": "text", + "content": ". The training of the framework is solely supervised by mean-squared error (MSE) loss. MMVP consists of three steps as follows:" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "spans": [ + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "text", + "content": "Step 1: Spatial feature extraction. We use an RRDBs [44] based network architecture to model an image encoding function " + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "inline_equation", + "content": "\\Omega" + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "text", + "content": ", defined in eq. 1. This image encoder embeds each frame " + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "inline_equation", + "content": "I_{i}, i \\in \\{1,2,\\dots,T\\}" + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "text", + "content": " in a down-sample hidden space separately and outputs their corresponding hidden features " + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "inline_equation", + "content": "f_{i}" + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "text", + "content": ". In MMVP, besides the image encoder, we have an extra filter block that models a filtering function " + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "inline_equation", + "content": "\\Theta" + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "text", + "content": " defined in eq. 2. It takes " + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "inline_equation", + "content": "f_{i}" + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "text", + "content": " as the input and aims to generate " + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "inline_equation", + "content": "g_{i}" + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "text", + "content": ". As the module name indicates, the filter block aims to filter out motion-irrelevant features of " + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "inline_equation", + "content": "f_{i}" + }, + { + "bbox": [ + 304, + 472, + 546, + 602 + ], + "type": "text", + "content": " for motion matrix construction. We will introduce the details in Sec. 3.2." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "text", + "content": "Step 2: Motion matrix construction and prediction. MMVP generates a set of motion matrices " + }, + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{M}_{i,i + 1}\\} ,i\\in" + }, + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\{1,2,\\dots,T - 1\\}" + }, + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "text", + "content": " for every two consecutive frames based on their feature pairs " + }, + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\{g_i,g_{i + 1}\\}" + }, + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "text", + "content": ". Then, a matrix predicting function " + }, + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\Phi" + }, + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "text", + "content": " defined in eq. 4 takes " + }, + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{M}_{i,i + 1}\\}" + }, + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "text", + "content": " as the input and predicts future matrices " + }, + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\{\\widehat{\\mathbf{M}_{T,T + j}}\\} ,j\\in \\{T,\\dots,T + T'\\}" + }, + { + "bbox": [ + 304, + 604, + 547, + 714 + ], + "type": "text", + "content": ". Sec. 3.3 will elaborate on the definition and construction procedures of the motion matrices, and Sec. 3.4 will demonstrate the inner structure of the matrix predictor." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "4275" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 156 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 156 + ], + "type": "text", + "content": "Step 3: Future composing and decoding. Using the output of steps 1 and 2, MMVP composes the unknown information for future frames. Then, a future decoding module takes the composed features as the input and outputs the final prediction. We will introduce the feature composition procedure in Sec. 3.5 and the future decoding module in Sec. 3.6." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 163, + 194, + 176 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 163, + 194, + 176 + ], + "spans": [ + { + "bbox": [ + 47, + 163, + 194, + 176 + ], + "type": "text", + "content": "3.2. Spatial Feature Extraction" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 182, + 288, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 182, + 288, + 205 + ], + "spans": [ + { + "bbox": [ + 47, + 182, + 288, + 205 + ], + "type": "text", + "content": "Spatial feature extraction involves two components of the MMVP framework: image encoder, and filter block." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "spans": [ + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "type": "text", + "content": "The image encoder " + }, + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "type": "inline_equation", + "content": "\\Omega" + }, + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "type": "text", + "content": " in MMVP encodes every " + }, + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "type": "inline_equation", + "content": "I_{i}" + }, + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "type": "text", + "content": " from the input data sequence to their corresponding features " + }, + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "type": "inline_equation", + "content": "f_{i}" + }, + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "type": "text", + "content": " individually. The filter block " + }, + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "type": "inline_equation", + "content": "\\Theta" + }, + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "type": "text", + "content": " subsequently processes " + }, + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "type": "inline_equation", + "content": "f_{i}" + }, + { + "bbox": [ + 47, + 206, + 287, + 266 + ], + "type": "text", + "content": " and makes it ready for the construction of a motion matrix. Formally," + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 141, + 266, + 287, + 278 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 141, + 266, + 287, + 278 + ], + "spans": [ + { + "bbox": [ + 141, + 266, + 287, + 278 + ], + "type": "interline_equation", + "content": "f _ {i} = \\Omega \\left(I _ {i}\\right), \\tag {1}", + "image_path": "3ffad37077ec65994a654fbf383b5ab84362fe8402f280fd80b40357741ab254.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 141, + 282, + 287, + 295 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 141, + 282, + 287, + 295 + ], + "spans": [ + { + "bbox": [ + 141, + 282, + 287, + 295 + ], + "type": "interline_equation", + "content": "g _ {i} = \\Theta (f _ {i}), \\tag {2}", + "image_path": "dfd5b71024fa6181b5963a8e5fbf5955cb7a43227284cf993d8bea9bdcb94a58.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 300, + 287, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 300, + 287, + 361 + ], + "spans": [ + { + "bbox": [ + 47, + 300, + 287, + 361 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 300, + 287, + 361 + ], + "type": "inline_equation", + "content": "i \\in \\{1, 2, \\dots, T\\}" + }, + { + "bbox": [ + 47, + 300, + 287, + 361 + ], + "type": "text", + "content": ". We use a convolutional network with residual in residual dense blocks (RRDBs) [44] to implement the image encoder, and we use a two-layer convolutional network to implement the filter block. See the detailed network architecture in Appendix." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 361, + 287, + 456 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 361, + 287, + 456 + ], + "spans": [ + { + "bbox": [ + 46, + 361, + 287, + 456 + ], + "type": "text", + "content": "Next, the output features of the image encoder will take participate in the future feature composition, while the output of the filter block is only used for motion matrices construction. The existence of the filter block helps the model to filter out irrelevant features from the image encoder output and allows the construction of motion matrices to focus more on motion-related features. See Table 2 for the ablation study about the filter block." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 464, + 204, + 475 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 464, + 204, + 475 + ], + "spans": [ + { + "bbox": [ + 47, + 464, + 204, + 475 + ], + "type": "text", + "content": "3.3. Motion Matrix Construction" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "spans": [ + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "content": "Given the output of the filter block " + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "inline_equation", + "content": "g_{i} \\in \\mathbb{R}^{\\frac{H}{S} \\times \\frac{W}{S}}" + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "inline_equation", + "content": "i \\in \\{1,2,\\dots,T\\}" + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "content": ", we denote the feature patch at " + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "inline_equation", + "content": "(h,w)" + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "inline_equation", + "content": "w \\in \\{0,1,2,\\frac{W}{S} - 1\\}" + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "inline_equation", + "content": "h \\in \\{0,1,2,\\frac{H}{S} - 1\\}" + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "inline_equation", + "content": "g_{i}^{h,w}" + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "inline_equation", + "content": "H" + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "inline_equation", + "content": "W" + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "content": " are the input images' height and width, and " + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "content": " is the downsampling ratio to the original image; thus " + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "inline_equation", + "content": "\\frac{H}{S}" + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "inline_equation", + "content": "\\frac{W}{S}" + }, + { + "bbox": [ + 47, + 480, + 287, + 555 + ], + "type": "text", + "content": " are respectively the feature map's height and width." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "spans": [ + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "type": "text", + "content": "For two consecutive frames' feature " + }, + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "type": "inline_equation", + "content": "\\{g_i, g_{i+1}\\}" + }, + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "type": "text", + "content": ", we calculate the cosine similarity for each and every pair of feature patches to construct a 4D motion matrix " + }, + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_{i,i+1} \\in \\mathbb{R}^{\\frac{H}{S} \\times \\frac{W}{S} \\times \\frac{H}{S} \\times \\frac{W}{S}}" + }, + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "type": "text", + "content": ". We denote the element of the matrix " + }, + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_{i,i+1}" + }, + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "type": "text", + "content": " at " + }, + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "type": "inline_equation", + "content": "(h_i, w_i, h_{i+1}, w_{i+1})" + }, + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_{i,i+1}^{h_i, w_i, h_{i+1}, w_{i+1}}" + }, + { + "bbox": [ + 47, + 555, + 287, + 619 + ], + "type": "text", + "content": ", and let" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 77, + 635, + 287, + 653 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 77, + 635, + 287, + 653 + ], + "spans": [ + { + "bbox": [ + 77, + 635, + 287, + 653 + ], + "type": "interline_equation", + "content": "\\mathbf {M} _ {i, i + 1} ^ {h _ {i}, w _ {i}, h _ {i + 1}, w _ {i + 1}} = D _ {c} \\left(g _ {i} ^ {h _ {i}, w _ {i}}, g _ {i + 1} ^ {h _ {i + 1}, w _ {i + 1}}\\right). \\tag {3}", + "image_path": "924df6263c791af2a506b3655cfef1dfed478a4774adc938c6c8c2a7f68b8d72.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "text", + "content": "In the equation, " + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "inline_equation", + "content": "D_{c}" + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "text", + "content": " is the cosine similarity, " + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "inline_equation", + "content": "g_{i}^{h_{i},w_{i}}" + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "text", + "content": " is the feature patch of frame " + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "text", + "content": " with the index of " + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "inline_equation", + "content": "(h_i,w_i)" + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "inline_equation", + "content": "g_{i + 1}^{h_{i + 1},w_{i + 1}}" + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "text", + "content": " is the feature patch of frame " + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "inline_equation", + "content": "i + 1" + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "text", + "content": " with the index of " + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "inline_equation", + "content": "(h_{i + 1},w_{i + 1})" + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "text", + "content": ". With a feature patch at " + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "inline_equation", + "content": "(h_i,w_i)" + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "text", + "content": " of " + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "inline_equation", + "content": "g_{i}" + }, + { + "bbox": [ + 47, + 663, + 287, + 715 + ], + "type": "text", + "content": " as an" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 71, + 545, + 209 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 71, + 545, + 209 + ], + "spans": [ + { + "bbox": [ + 304, + 71, + 545, + 209 + ], + "type": "text", + "content": "example, the matrix " + }, + { + "bbox": [ + 304, + 71, + 545, + 209 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_{i,i + 1}^{h_i,w_i}\\in \\mathbb{R}^{H\\times W}" + }, + { + "bbox": [ + 304, + 71, + 545, + 209 + ], + "type": "text", + "content": " can be regarded as a heatmap that reflects how much impact " + }, + { + "bbox": [ + 304, + 71, + 545, + 209 + ], + "type": "inline_equation", + "content": "g_{i}^{h_{i},w_{i}}" + }, + { + "bbox": [ + 304, + 71, + 545, + 209 + ], + "type": "text", + "content": " has on " + }, + { + "bbox": [ + 304, + 71, + 545, + 209 + ], + "type": "inline_equation", + "content": "g_{i + 1}" + }, + { + "bbox": [ + 304, + 71, + 545, + 209 + ], + "type": "text", + "content": ", or more intuitively, the motion tendency of " + }, + { + "bbox": [ + 304, + 71, + 545, + 209 + ], + "type": "inline_equation", + "content": "g_{i}^{h_{i},w_{i}}" + }, + { + "bbox": [ + 304, + 71, + 545, + 209 + ], + "type": "text", + "content": " (see Figure 5 for illustration). It is similar to the definition of optical flow [17], which determines the movement of a pixel or superpixel. The difference between optical flow and motion matrix is that motion matrix does not strictly define a one-to-one relationship between the pixels or superpixels of the current frame and those of the next frame. It is a more practical assumption in the video prediction task that one current feature patch may influence several future feature patches." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 217, + 412, + 228 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 217, + 412, + 228 + ], + "spans": [ + { + "bbox": [ + 306, + 217, + 412, + 228 + ], + "type": "text", + "content": "3.4. Matrix Prediction" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "text", + "content": "Given the motion matrices of the past " + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "text", + "content": " frames " + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{M}_{1,2},\\mathbf{M}_{2,3},\\dots,\\mathbf{M}_{T - 1,T}\\}" + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "text", + "content": ", the matrix predictor " + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "inline_equation", + "content": "\\Psi" + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "text", + "content": " predicts the future matrices " + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{M}_{T,T + 1},\\mathbf{M}_{T,T + 2},\\dots,\\mathbf{M}_{T,T'}\\}" + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "text", + "content": ". Instead of predicting the motion matrices between the consecutive frames, we predict the ones between the last observed frame " + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "inline_equation", + "content": "I_{T}" + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "text", + "content": " and every future frame " + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "inline_equation", + "content": "I_{T + j},j\\in \\{1,2,\\dots,T'\\}" + }, + { + "bbox": [ + 305, + 235, + 545, + 308 + ], + "type": "text", + "content": ", as" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 315, + 327, + 545, + 346 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 327, + 545, + 346 + ], + "spans": [ + { + "bbox": [ + 315, + 327, + 545, + 346 + ], + "type": "interline_equation", + "content": "\\left\\{\\widehat {\\mathbf {M} _ {T , T + j} ^ {w , h}} \\right\\} = \\Psi \\left(\\left\\{\\mathbf {M} _ {i, i + 1} ^ {w, h} \\right\\}\\right), \\forall i \\in \\{1, 2, \\dots , T - 1 \\}, \\tag {4}", + "image_path": "f6f5f55367f525cff1168fb7b19344132fe6c973c9b4d8656b1cdd48f1586eed.jpg" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "spans": [ + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_{i,i+1}^{w,h} \\in \\mathbb{R}^{H \\times W}" + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "inline_equation", + "content": "w \\in \\{1,2,\\dots,\\frac{W}{S}\\}" + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "inline_equation", + "content": "h \\in \\{1,2,\\dots,\\frac{H}{S}\\}" + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "text", + "content": ". This design aims to reduce the accumulative error during feature composition and is validated by the long-term prediction setting shown in Table 3. Since for this work, we focus on testing the function and performance of the MMVP framework, we report the use of a simple " + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "inline_equation", + "content": "3D" + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "text", + "content": " fully convolutional architecture to implement " + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "inline_equation", + "content": "\\Psi" + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "text", + "content": ". Fellow researchers can choose to easily replace the implementation of " + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "inline_equation", + "content": "\\Psi" + }, + { + "bbox": [ + 304, + 355, + 546, + 479 + ], + "type": "text", + "content": " with more advanced temporal modules if they wish to pursue better performances." + } + ] + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 307, + 490, + 547, + 654 + ], + "blocks": [ + { + "bbox": [ + 307, + 490, + 547, + 654 + ], + "lines": [ + { + "bbox": [ + 307, + 490, + 547, + 654 + ], + "spans": [ + { + "bbox": [ + 307, + 490, + 547, + 654 + ], + "type": "image", + "image_path": "da450c0279acec735040303e38e74079bf62a9f0b9190bdd1a3335f3cc4741c6.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 670, + 545, + 707 + ], + "lines": [ + { + "bbox": [ + 304, + 670, + 545, + 707 + ], + "spans": [ + { + "bbox": [ + 304, + 670, + 545, + 707 + ], + "type": "text", + "content": "Figure 4: All scales of image features and the original frames can join the future composition with predicted motion matrices through pixel unshuffle and shuffle operations." + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "4276" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 220, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 220, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 220, + 85 + ], + "type": "text", + "content": "3.5. Multi-scale Future Composition" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 91, + 287, + 126 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 91, + 287, + 126 + ], + "spans": [ + { + "bbox": [ + 47, + 91, + 287, + 126 + ], + "type": "text", + "content": "The future composition step generates information for the future frames using the observed information and the motion matrices. It is formulated as" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 73, + 134, + 287, + 167 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 73, + 134, + 287, + 167 + ], + "spans": [ + { + "bbox": [ + 73, + 134, + 287, + 167 + ], + "type": "interline_equation", + "content": "\\widehat {\\mathcal {X} _ {T + j}} = \\sum_ {i = 1} ^ {T} \\left(\\mathcal {X} _ {i} \\times \\prod_ {n = i} ^ {T - 1} \\mathbf {M} _ {n, n + 1} \\times \\widehat {\\mathbf {M} _ {T , T + j}}\\right). \\tag {5}", + "image_path": "0aa8338458f14925d9efe58f8db2fabe3324e4410191ea9c13b82ddf0ea076b2.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 174, + 288, + 473 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 174, + 288, + 473 + ], + "spans": [ + { + "bbox": [ + 47, + 174, + 288, + 473 + ], + "type": "text", + "content": "As the equation indicates, instead of only using the information of the last observed frame, we use all observed information for future composition and lower the weight of earlier frames through repeated multiplication of the motion matrices. The " + }, + { + "bbox": [ + 47, + 174, + 288, + 473 + ], + "type": "inline_equation", + "content": "\\mathcal{X}" + }, + { + "bbox": [ + 47, + 174, + 288, + 473 + ], + "type": "text", + "content": " in the equation represents the observed information of the past frames. The information can be the output features of the image encoder with different scales " + }, + { + "bbox": [ + 47, + 174, + 288, + 473 + ], + "type": "inline_equation", + "content": "f_{i} \\in \\mathbb{R}^{H^{s} \\times W^{s} \\times C}" + }, + { + "bbox": [ + 47, + 174, + 288, + 473 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 47, + 174, + 288, + 473 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 47, + 174, + 288, + 473 + ], + "type": "text", + "content": " is the feature length; the information can also be the observed frames " + }, + { + "bbox": [ + 47, + 174, + 288, + 473 + ], + "type": "inline_equation", + "content": "I_{i} \\in \\mathbb{R}^{H \\times W \\times 3}" + }, + { + "bbox": [ + 47, + 174, + 288, + 473 + ], + "type": "text", + "content": ". Since the motion matrices are constructed from a certain scale of image features, there will be incompatibilities between the matrices and some features. To enable matrix multiplication between the motion matrices and the observed features (at any scales) or images, we borrow the pixel unshuffle and shuffle operations from [39]. The pixel unshuffle operation reshapes features or images into the identical scale as the motion matrices for matrix multiplication. Afterward, the pixel shuffle operation reshapes the results of the matrix multiplication back to the original scales of the features or images. See Figure 4 for demonstration. This whole process involves little information loss. In Table 6, we examine the multi-scale feature composition design. We find out that in general, the system achieves better performance when more scales of features take part in the feature composition." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 482, + 149, + 495 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 482, + 149, + 495 + ], + "spans": [ + { + "bbox": [ + 47, + 482, + 149, + 495 + ], + "type": "text", + "content": "3.6. Future Decoding" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 501, + 287, + 621 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 501, + 287, + 621 + ], + "spans": [ + { + "bbox": [ + 46, + 501, + 287, + 621 + ], + "type": "text", + "content": "The future decoding procedure is used for aggregating and processing the composed features to formulate the final output. Since in the feature composition procedure, all scales of features are able to compose their corresponding scales of features for future frames, we adopt the decoder structure of UNet [37] with RRDB blocks [44] in the end to implement MMVP's image decoder. This design allows the composed features from all scales of image features, as well as the original images, to contribute to the final output. We use MSE loss to supervise the framework training." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 633, + 124, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 633, + 124, + 647 + ], + "spans": [ + { + "bbox": [ + 47, + 633, + 124, + 647 + ], + "type": "text", + "content": "4. Experiment" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "content": "In this section, we evaluate MMVP quantitatively and qualitatively against existing state-of-the-art methods on various publicly available datasets. In addition, we analyze MMVP through a set of ablation studies on the UCF Sports dataset to better illustrate our design logic." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 72, + 369, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 369, + 83 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 369, + 83 + ], + "type": "text", + "content": "4.1. Datasets" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 91, + 547, + 115 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 91, + 547, + 115 + ], + "spans": [ + { + "bbox": [ + 305, + 91, + 547, + 115 + ], + "type": "text", + "content": "We briefly review three widely used datasets and their configurations for MMVP evaluation." + } + ] + } + ], + "index": 9 + }, + { + "type": "table", + "bbox": [ + 315, + 137, + 537, + 186 + ], + "blocks": [ + { + "bbox": [ + 332, + 121, + 518, + 133 + ], + "lines": [ + { + "bbox": [ + 332, + 121, + 518, + 133 + ], + "spans": [ + { + "bbox": [ + 332, + 121, + 518, + 133 + ], + "type": "text", + "content": "Table 1: Experiment settings for each dataset." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 315, + 137, + 537, + 186 + ], + "lines": [ + { + "bbox": [ + 315, + 137, + 537, + 186 + ], + "spans": [ + { + "bbox": [ + 315, + 137, + 537, + 186 + ], + "type": "table", + "html": "
DatasetResolutionTrainTest
UCF Sports512 × 5124 → 14 → 6
KTH128 × 12810 → 20 or 4010 → 20 or 40
Moving MNIST64 × 6410 → 1010 → 10
", + "image_path": "6754e9d9f6abeeb2db0ea1005dea3dbf95259111b4e2cd219f96bf0302b2aecc.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 196, + 545, + 448 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 196, + 545, + 448 + ], + "spans": [ + { + "bbox": [ + 304, + 196, + 545, + 448 + ], + "type": "text", + "content": "UCF Sports [36] contains 150 video sequences collected from various sports scenes with 10 different action types including running, kicking, and diving. It is regarded as a challenging dataset given its low frame rate (10 fps), high resolution " + }, + { + "bbox": [ + 304, + 196, + 545, + 448 + ], + "type": "inline_equation", + "content": "(480 \\times 720)" + }, + { + "bbox": [ + 304, + 196, + 545, + 448 + ], + "type": "text", + "content": ", and complex motion patterns. The video sequences in this dataset contain both rapid foreground (e.g. athletes) and background movements (e.g. the camera motion). We perform two different training/validation splits of this dataset, splits from STRPM [5] and our own splits, to facilitate different evaluation purposes. We use the STRPM splits for performance comparison with other methods (Table 4). In STRPM, long video sequences are cut into several short clips; for a particular sequence, some of its clips may be put into the training split, and others into the validation split. To avoid the appearance features of certain sequences in the validation set to be exposed in the training set, and to thoroughly evaluate MMVP's capability of video prediction, we generate our own splits for UCF Sports, which choose " + }, + { + "bbox": [ + 304, + 196, + 545, + 448 + ], + "type": "inline_equation", + "content": "90\\%" + }, + { + "bbox": [ + 304, + 196, + 545, + 448 + ], + "type": "text", + "content": " of the video sequences from each action type to form the training samples, and the rest " + }, + { + "bbox": [ + 304, + 196, + 545, + 448 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 304, + 196, + 545, + 448 + ], + "type": "text", + "content": " to form the validation samples." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "spans": [ + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "text", + "content": "Notably, within the same validation set, the difficulty level of different samples varies a lot. Some easier video clips contain static backgrounds and slow-moving objects, while others are more difficult for involving drastic camera movement and/or fast-moving objects. To better understand the model's prediction ability in different scenarios, we apply certain thresholds of the structural similarity index measure (SSIM) between the last observed frame and the first future frame to divide the UCF Sports validation set into three subsets: the easy " + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "inline_equation", + "content": "(\\mathrm{SSIM} \\leq 0.9)" + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "text", + "content": ", intermediate " + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "inline_equation", + "content": "(0.6 \\leq \\mathrm{SSIM} < 0.9)" + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "text", + "content": ", and hard subsets " + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "inline_equation", + "content": "(\\mathrm{SSIM} < 0.6)" + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "text", + "content": ", which respectively take up " + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "inline_equation", + "content": "66\\%" + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "inline_equation", + "content": "26\\%" + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "inline_equation", + "content": "8\\%" + }, + { + "bbox": [ + 304, + 449, + 545, + 592 + ], + "type": "text", + "content": " of the full set." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 593, + 547, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 593, + 547, + 640 + ], + "spans": [ + { + "bbox": [ + 305, + 593, + 547, + 640 + ], + "type": "text", + "content": "We use our own UCF Sports splits in the ablation studies (Sec. 4.3). For comparisons, we also train and test STIP [4] (extension of STRPM [5]) and SimVP [12] on our own UCF Sports splits; see Table 6." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "text", + "content": "KTH [38] contains videos of 25 individuals performing six types of actions, i.e., walking, jogging, running, boxing, hand-waving, and hand-clapping. Following previous works [43, 46, 12], we use persons 1-16 for training and persons 17-25 for validation. The videos in KTH are in grayscale, but the challenging part of this dataset is its ex" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "4277" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "type": "text", + "content": "periment setting, which requires the system to output 20 or 40 frames given only 10 past frames." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 96, + 288, + 204 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 96, + 288, + 204 + ], + "spans": [ + { + "bbox": [ + 47, + 96, + 288, + 204 + ], + "type": "text", + "content": "Moving MNIST [41] is a synthetic dataset. Each sequence in the dataset consists of two digits moving independently within the " + }, + { + "bbox": [ + 47, + 96, + 288, + 204 + ], + "type": "inline_equation", + "content": "64 \\times 64" + }, + { + "bbox": [ + 47, + 96, + 288, + 204 + ], + "type": "text", + "content": " grid and bouncing off the boundary. During the training time, by assigning different initial locations and velocities to each digit, one can generate an infinite number of sequences, and train the system to predict the future 10 frames from the previous 10 frames. For fair comparisons, we use the pre-generated 10000 sequences[12] for validation." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 213, + 105, + 224 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 213, + 105, + 224 + ], + "spans": [ + { + "bbox": [ + 47, + 213, + 105, + 224 + ], + "type": "text", + "content": "4.2. Metrics" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 231, + 288, + 387 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 231, + 288, + 387 + ], + "spans": [ + { + "bbox": [ + 46, + 231, + 288, + 387 + ], + "type": "text", + "content": "We use the peak signal-to-noise ratio (PSNR) and structural similarity index measure (SSIM) to evaluate the image quality of the predicted frames. We use the implementation of PSNR and SSIM from the package scikit-learn [34]. For the UCF Sports dataset, we use Learned Perceptual Image Patch Similarity (LPIPS) [58] for better comparison with existing methods. LPIPS represents the perceptual quality of the predicted frames. It measures the feature distance of corresponding image patches between the predicted frames and the ground truth. Following the setting of these previous works, in the experiments on Moving MNIST, we use the sum of the mean squared error (MSE) from the entire frame to evaluate the image quality." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 396, + 141, + 407 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 396, + 141, + 407 + ], + "spans": [ + { + "bbox": [ + 47, + 396, + 141, + 407 + ], + "type": "text", + "content": "4.3. Ablation Study" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 414, + 287, + 474 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 414, + 287, + 474 + ], + "spans": [ + { + "bbox": [ + 47, + 414, + 287, + 474 + ], + "type": "text", + "content": "We conduct the ablation study of future composition (Table 6), filter block (3rd and 4th rows of Table 2), and hyperparameters for both the image encoder/decoder and the matrix predictor (1st, 2nd, and 4th rows of Table 2) on our splits of the UCF Sports dataset." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 474, + 288, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 474, + 288, + 700 + ], + "spans": [ + { + "bbox": [ + 47, + 474, + 288, + 700 + ], + "type": "text", + "content": "We first examine how the number of feature scales for feature composition impacts the results. Since we use the UNet structure with three times downsampling/upsampling operations to encode, we have four different scales of features for composition. For UCF Sports, the scales are " + }, + { + "bbox": [ + 47, + 474, + 288, + 700 + ], + "type": "inline_equation", + "content": "1, \\frac{1}{2}, \\frac{1}{8}, \\frac{1}{16}" + }, + { + "bbox": [ + 47, + 474, + 288, + 700 + ], + "type": "text", + "content": ". The motion matrices are constructed using features of " + }, + { + "bbox": [ + 47, + 474, + 288, + 700 + ], + "type": "inline_equation", + "content": "\\frac{1}{8}" + }, + { + "bbox": [ + 47, + 474, + 288, + 700 + ], + "type": "text", + "content": " scale. From Table 6 3rd to 5th rows, we observe consistent performance boosts on all metrics and subsets when we involve more scales of features for composition. We then test if using images for feature composition also boosts performance. By comparing the 5th and 6th rows of Table 6, we can still see an increasing pattern. However, since the scale of the image is identical to the largest scale of the features, to avoid redundancy and possible conflicts, we remove the features of the largest scale and produce the results of the last row in Table 6. We then see a comparable result to the one that uses all scales of features as well as the image. We adopt the model setting of the last row for the rest of the experiments." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 59, + 701, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 701, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 59, + 701, + 287, + 713 + ], + "type": "text", + "content": "As mentioned in Sec. 3.2, we do not directly use the out" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": "put of the image encoder to construct the motion matrices. Instead, we add a filter block to filter out irrelevant features and help the motion matrices focus more on describing the temporal similarity regarding the motion-related features. Table 2 shows that the model with the filter block generally achieves better results on the UCF Sports validation set." + } + ] + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 312, + 200, + 536, + 270 + ], + "blocks": [ + { + "bbox": [ + 304, + 155, + 545, + 192 + ], + "lines": [ + { + "bbox": [ + 304, + 155, + 545, + 192 + ], + "spans": [ + { + "bbox": [ + 304, + 155, + 545, + 192 + ], + "type": "text", + "content": "Table 2: Ablation study on UCF Sports with LPIPS metrics (the lower the better), including the feature length of image and motion, and the usage of the filter block (F-Block)." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 312, + 200, + 536, + 270 + ], + "lines": [ + { + "bbox": [ + 312, + 200, + 536, + 270 + ], + "spans": [ + { + "bbox": [ + 312, + 200, + 536, + 270 + ], + "type": "table", + "html": "
ImgMotionF-BlockFullEasyIntermediateHardParam #
164✓0.11840.05920.18110.41680.70M
168✓0.11750.06000.17680.41220.71M
328×0.11240.05740.17290.38192.57M
328✓0.10620.05800.15690.35102.79M
STIPHR [4]0.16260.10660.22710.445018.05M
SimVP [12]0.13260.05840.19510.56003.47M
", + "image_path": "009e55d3f09982a00309ed9cd74e2382d0b01e7dbf62522a241f4b0ea7efeeb0.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 275, + 545, + 335 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 275, + 545, + 335 + ], + "spans": [ + { + "bbox": [ + 304, + 275, + 545, + 335 + ], + "type": "text", + "content": "Furthermore, Table 2 also shows an ablation study on the feature length of the appearance-related modules (image encoder and decoder) and the motion-related module (matrix predictor). We define the configuration of the second row as the MMVP-mini for Figure 1." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 344, + 462, + 356 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 344, + 462, + 356 + ], + "spans": [ + { + "bbox": [ + 306, + 344, + 462, + 356 + ], + "type": "text", + "content": "4.4. Motion Matrix Visualization" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 362, + 545, + 483 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 362, + 545, + 483 + ], + "spans": [ + { + "bbox": [ + 304, + 362, + 545, + 483 + ], + "type": "text", + "content": "In Figure 5, we visualize the predicted motion matrices for certain selected feature patches. In all the demonstrated samples, the many-to-many relationships described by the predicted motion matrices are able to accurately capture the feature patches moving tendency. They show that the motion matrix can describe a wide range of motion patterns and scenarios, including multiple objects (1st sample of UCF Sports), the single person moving (KTH), multiple persons moving and camera moving (2nd sample of UCF Sports), and synthesized motions (Moving MNIST)." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 491, + 485, + 503 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 491, + 485, + 503 + ], + "spans": [ + { + "bbox": [ + 305, + 491, + 485, + 503 + ], + "type": "text", + "content": "4.5. Comparison with SOTA Methods" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 510, + 545, + 545 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 510, + 545, + 545 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 545, + 545 + ], + "type": "text", + "content": "We compare MMVP with existing SOTA methods on three popular datasets: UCF Sports (STRPM [5] splits, Table 4), KTH (Table 3), and Moving MNIST (Table 5)." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 546, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 546, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 546, + 545, + 713 + ], + "type": "text", + "content": "On the UCF Sports dataset, we observe large performance gains by MMVP compared to other methods. As mentioned above, the motion patterns in UCF Sports are the most complex of the three datasets due to many difficult cases, e.g., fast movement, camera moving, and motion blur. But the two-stream design of MMVP has shown its ability in such complex scenarios. Meanwhile, the video resolution of UCF Sports is also the highest among the three datasets. Most existing methods in Table 4 are inherently not designed for high-resolution videos, which requires larger network capacities to maintain appearance information. Although STRPM [5] and STIP [4] proposed residual temporal modules designed for high-resolution videos and they could largely surpass previous methods on both" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "4278" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 90, + 68, + 512, + 252 + ], + "blocks": [ + { + "bbox": [ + 90, + 68, + 512, + 252 + ], + "lines": [ + { + "bbox": [ + 90, + 68, + 512, + 252 + ], + "spans": [ + { + "bbox": [ + 90, + 68, + 512, + 252 + ], + "type": "image", + "image_path": "a667b0af9fb6c4ae95d91afbddb433ddaa4930524be4a12a5761ee817292b6a6.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 258, + 548, + 309 + ], + "lines": [ + { + "bbox": [ + 46, + 258, + 548, + 309 + ], + "spans": [ + { + "bbox": [ + 46, + 258, + 548, + 309 + ], + "type": "text", + "content": "Figure 5: Predicted motion matrix visualization. We highlight the selected feature patch(es) at " + }, + { + "bbox": [ + 46, + 258, + 548, + 309 + ], + "type": "inline_equation", + "content": "(h,w)" + }, + { + "bbox": [ + 46, + 258, + 548, + 309 + ], + "type": "text", + "content": " in the last observed frame " + }, + { + "bbox": [ + 46, + 258, + 548, + 309 + ], + "type": "inline_equation", + "content": "I_{T}" + }, + { + "bbox": [ + 46, + 258, + 548, + 309 + ], + "type": "text", + "content": " in red and visualize their corresponding predicted motion matrices " + }, + { + "bbox": [ + 46, + 258, + 548, + 309 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_{T,T + 1}^{h,w}\\in \\mathbb{R}^{H\\times W}" + }, + { + "bbox": [ + 46, + 258, + 548, + 309 + ], + "type": "text", + "content": " overlaying with the first future frame " + }, + { + "bbox": [ + 46, + 258, + 548, + 309 + ], + "type": "inline_equation", + "content": "I_{T + 1}" + }, + { + "bbox": [ + 46, + 258, + 548, + 309 + ], + "type": "text", + "content": ". A brighter color indicates a higher predicted value. We select two samples for each dataset. From left to right, samples originate in the validation set of UCF Sports, KTH, and Moving MNIST." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 323, + 288, + 419 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 323, + 288, + 419 + ], + "spans": [ + { + "bbox": [ + 46, + 323, + 288, + 419 + ], + "type": "text", + "content": "metrics, the appearance information loss in their methods is still unavoidable. MMVP, nevertheless, allows the image and multi-scale features to reach the decoder through a feature composing procedure, successfully minimizes the information loss, and achieves the best performance among all methods across all metrics. MMVP's success on the UCF Sports dataset validates its readiness for real-world applications, and its scalability for high-resolution videos." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 423, + 287, + 603 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 423, + 287, + 603 + ], + "spans": [ + { + "bbox": [ + 46, + 423, + 287, + 603 + ], + "type": "text", + "content": "Another notable result is MMVP's ability in long-term information preservation; see Table 3. Despite having lower video resolutions and less complex motion patterns than UCF Sports, KTH as a real-world dataset still presents a difficulty as it requires systems to do long-term prediction given short-term observations. On the KTH dataset, MMVP achieves the #1 performance on SSIM metrics for both experiment settings with a small performance gap (27.54 to 26.35) in PSNR between the two settings. This is contributed by the design that the matrix predictor of MMVP predicts the temporal similarity matrices between the future frames and the last observed frame instead of their predecessors. Then, every predicted frame is composed of valid observed information. It reduces accumulated errors and ensures good performance for long-term prediction." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "content": "Compared to the performance gains on UCF Sports, MMVP does not show much advantage on the Moving MNIST dataset. One speculation is that with video prediction research advancing, the problem of two-digits Moving MNIST with low resolution " + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "inline_equation", + "content": "(64\\times 64)" + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "content": " is nearly solved. With sufficient training time [12], current video prediction systems may all be able to achieve promising results. To further promote the growth of this field, researchers can consider more challenging datasets and experiment settings." + } + ] + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 307, + 337, + 544, + 526 + ], + "blocks": [ + { + "bbox": [ + 317, + 322, + 536, + 334 + ], + "lines": [ + { + "bbox": [ + 317, + 322, + 536, + 334 + ], + "spans": [ + { + "bbox": [ + 317, + 322, + 536, + 334 + ], + "type": "text", + "content": "Table 3: Performance comparison on the KTH dataset" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 307, + 337, + 544, + 526 + ], + "lines": [ + { + "bbox": [ + 307, + 337, + 544, + 526 + ], + "spans": [ + { + "bbox": [ + 307, + 337, + 544, + 526 + ], + "type": "table", + "html": "
MethodKTH10 → 20KTH10 → 40
SSIM ↑PSNR ↑SSIM ↑PSNR ↑
MCnet (ICLR2017) [43]0.80425.950.7323.89
ConvLSTM (NeurIPS2015) [40]0.71223.580.63922.85
SAVP (arXiv2018) [25]0.74625.380.70123.97
VPN (PMLR2017) [23]0.74623.76--
DFN (NeurIPS2016) [20]0.79427.260.65223.01
fRNN (ECCV2018) [32]0.77126.120.67823.77
Znet (ICME2019) [56]0.81727.58--
SV2Pi (ICLR2018) [1]0.82627.560.77825.92
SV2Pv (ICLR2018) [1]0.83827.790.78926.12
PredRNN (NeurIPS2017) [47]0.83927.550.70324.16
VarNet (IROS2018) [22]0.84328.480.73925.37
SVAP-VAE (arXiv2018) [25]0.85227.770.81126.18
PredRNN++ (ICML2018) [45]0.86528.470.74125.21
MSNET (BMVC2019) [26]0.87627.08--
E3d-LSTM (ICLR2019) [46]0.87929.310.81027.24
STMFANet (CVPR2020) [21]0.89329.850.85127.56
MMVP (ours)0.90627.540.88826.35
", + "image_path": "a63582f50e32287d00a04e5034897aab630594b9e255be2b09a32aa879779b04.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 544, + 546, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 544, + 546, + 687 + ], + "spans": [ + { + "bbox": [ + 304, + 544, + 546, + 687 + ], + "type": "text", + "content": "Moreover, we analyze MMVP's performance on data of different difficulty levels using our own split of the UCF Sports dataset. We define the difficulty of a video using the SSIM between the last observed frame and the first frame to be predicted. This is because a lower SSIM indicates a larger difference between the two frames, and less possibility for a system to take the shortcut by using the residual information from past frames and not actually predicting the motion. Table 6 shows the quantitative evaluation compared with SimVP [12] and STIP [4]: as the difficulty level of the validation subset increases, the performance gap between MMVP and other methods also increases." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 689, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 546, + 714 + ], + "type": "text", + "content": "Besides quantitative evaluation, we also showcase several qualitative visualizations in Figure 6 and compare them" + } + ] + } + ], + "index": 8 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "4279" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 71, + 72, + 521, + 278 + ], + "blocks": [ + { + "bbox": [ + 71, + 72, + 521, + 278 + ], + "lines": [ + { + "bbox": [ + 71, + 72, + 521, + 278 + ], + "spans": [ + { + "bbox": [ + 71, + 72, + 521, + 278 + ], + "type": "image", + "image_path": "9dce96e9a3b87470096ffbe40c7ea4195192d63185d3bba2c3c3bd637000870b.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 148, + 282, + 443, + 295 + ], + "lines": [ + { + "bbox": [ + 148, + 282, + 443, + 295 + ], + "spans": [ + { + "bbox": [ + 148, + 282, + 443, + 295 + ], + "type": "text", + "content": "Figure 6: Qualitative results on our own splits of the UCF Sports dataset." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 48, + 316, + 321, + 477 + ], + "blocks": [ + { + "bbox": [ + 57, + 300, + 313, + 313 + ], + "lines": [ + { + "bbox": [ + 57, + 300, + 313, + 313 + ], + "spans": [ + { + "bbox": [ + 57, + 300, + 313, + 313 + ], + "type": "text", + "content": "Table 4: Performance comparison on UCF Sports STRPM split" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 316, + 321, + 477 + ], + "lines": [ + { + "bbox": [ + 48, + 316, + 321, + 477 + ], + "spans": [ + { + "bbox": [ + 48, + 316, + 321, + 477 + ], + "type": "table", + "html": "
Methodt=5t=10
PSNR↑LPIPS×100↓PSNR↑LPIPS×100↓
ConvLSTM (NeurIPS2015) [40]26.4332.2017.8058.78
BeyondMSE (ICLR2016) [30]26.4229.0118.4655.28
PredRNN (NeurIPS2017) [47]27.1728.1519.6555.34
PredRNN++ (ICML2018) [45]27.2626.8019.6756.79
SAVP (arXiv2018) [25]27.3525.4519.9049.91
SV2P (ICLR2018) [1]27.4425.8919.9751.33
E3D-LSTM (ICLR2019) [46]27.9825.1320.3347.76
CycleGAN (CVPR2019) [24]27.9922.9519.9944.93
CrevNet (ICLR2020) [55]28.2323.8720.3348.15
MotionRNN (CVPR2021) [51]27.6724.2320.0149.20
STRPM (CVPR2022) [5]28.5420.6920.5941.11
STIP (arXiv2022) [4]30.7512.7321.8339.67
DMVFN (CVPR2023) [19]30.0510.2422.6722.50
MMVP (Ours)31.687.8823.2522.24
", + "image_path": "a2f39eb6e48b3bfa7fff00f20fd02fbeaace96a3dccc48560ffd73917bbefe88.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_body" + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 361, + 341, + 518, + 452 + ], + "blocks": [ + { + "bbox": [ + 354, + 326, + 524, + 338 + ], + "lines": [ + { + "bbox": [ + 354, + 326, + 524, + 338 + ], + "spans": [ + { + "bbox": [ + 354, + 326, + 524, + 338 + ], + "type": "text", + "content": "Table 5: Comparisons on Moving MNIST" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 361, + 341, + 518, + 452 + ], + "lines": [ + { + "bbox": [ + 361, + 341, + 518, + 452 + ], + "spans": [ + { + "bbox": [ + 361, + 341, + 518, + 452 + ], + "type": "table", + "html": "
MethodMSESSIM
ConvLSTM (NIPS 2015) [40]103.30.707
PredRNN (NIPS 2017) [47]56.80.867
PredRNN-V2 (Arxiv 2021) [48]48.40.891
CausalLSTM (ICML 2018) [45]46.50.898
MIM (CVPR 2019) [49]44.20.910
E3D-LSTM (ICLR 2018) [46]41.30.920
PhyDNet (CVPR 2020) [14]24.40.947
CrevNet (ICLR 2020) [55]22.30.949
SimVP (CVPR 2022) [12]23.80.948
MMVP(ours)22.20.952
", + "image_path": "8309b880bb61a6985dca065fc6091b0b6cb9f0fcadb08cf088c11de9b67de445.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 52, + 506, + 541, + 586 + ], + "blocks": [ + { + "bbox": [ + 53, + 490, + 539, + 502 + ], + "lines": [ + { + "bbox": [ + 53, + 490, + 539, + 502 + ], + "spans": [ + { + "bbox": [ + 53, + 490, + 539, + 502 + ], + "type": "text", + "content": "Table 6: Ablation study on sources for future composition and the comparison with other SOTA methods on UCF Sports." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 52, + 506, + 541, + 586 + ], + "lines": [ + { + "bbox": [ + 52, + 506, + 541, + 586 + ], + "spans": [ + { + "bbox": [ + 52, + 506, + 541, + 586 + ], + "type": "table", + "html": "
MethodComposition sourceFull setEasy (SSIM ≥ 0.9)Intermediate (0.6 ≤ SSIM < 0.9)Hard (SSIM < 0.6)Param#
Img11/21/81/16SSIM ↑PSNR ↑LPIPS ↓SSIM ↑PSNR ↑LPIPS ↓SSIM ↑PSNR ↑LPIPS ↓SSIM ↑PSNR ↑LPIPS ↓
STIPHR [4]-0.881728.170.16260.949130.650.10660.835123.970.22710.467315.970.445018.05M
SimVP [12]-0.918929.970.13260.966432.870.05840.884525.790.19510.626718.990.56003.47M
MMVP×××✓✓0.900028.310.18740.937530.430.13420.875925.360.23040.659319.900.49922.75M
××✓✓✓0.928430.140.11150.966732.790.06030.893726.110.16930.715920.710.35702.79M
×✓✓✓✓0.929630.220.10640.966932.870.05760.896526.260.15710.719920.760.35552.80M
✓✓✓✓✓0.929630.290.10510.967532.990.05670.895826.220.15540.717520.760.35172.80M
✓×✓✓✓0.930030.350.10620.967433.050.05800.897026.290.15690.720320.840.35102.79M
", + "image_path": "fd1c344bcae81d77946ab7ea8bfe5df1f0e036d4207e29b6025c174a4af35da4.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 602, + 288, + 710 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 602, + 288, + 710 + ], + "spans": [ + { + "bbox": [ + 46, + 602, + 288, + 710 + ], + "type": "text", + "content": "with SimVP [12] which achieved the second-best performance on our splits of the UCF Sports dataset. We especially select four samples in the hard and intermediate subsets for visualization. The first sample in Figure 6 shows a far-away object with long-distance movement. This is caused by the low fps of the dataset. MMVP accurately captures the displacement of the object while not losing the color and shape of the object. The challenge of the second sample in Figure 6 is also typical to UFC Sports," + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 602, + 545, + 710 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 602, + 545, + 710 + ], + "spans": [ + { + "bbox": [ + 304, + 602, + 545, + 710 + ], + "type": "text", + "content": "i.e. fast movement with motion blur. MMVP is able to recover the correct shape of the athletes' feet even if they are blurred in the observed frames. The third and fourth samples both show a fast camera movement, with and without large foreground movements. Camera moving with complex backgrounds is extremely difficult for video prediction. Even SimVP, which generated high-quality images for most of the datasets, barely captured the camera movements in these two samples and caused drastic blurs. Benefiting from" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "4280" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "type": "text", + "content": "its appearance-agnostic motion prediction module, MMVP achieved impressive performance in such cases." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 109, + 117, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 109, + 117, + 121 + ], + "spans": [ + { + "bbox": [ + 47, + 109, + 117, + 121 + ], + "type": "text", + "content": "5. Discussion" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 129, + 289, + 308 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 129, + 289, + 308 + ], + "spans": [ + { + "bbox": [ + 46, + 129, + 289, + 308 + ], + "type": "text", + "content": "From Table 2 and Table 6 in Sec. 4, we observe that the proposed MMVP framework can always achieve better or comparable performance with significantly fewer parameters compared to the other SOTA methods. To better understand the high efficiency of MMVP, we break down a video prediction system into three components: i) content encoder, which encodes the image sequences; ii) prediction-related modules, which take charge of predicting features for future frames based on the output of the content encoder; iii) content decoder, which decodes the output of the predicted features output by the prediction-related modules. Then we examine the model size for each component in three video prediction systems: STIP [4], SimVP [12], and the proposed MMVP (configurations follow the second row and the fourth row in Table 2); see Table 7." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 308, + 289, + 538 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 308, + 289, + 538 + ], + "spans": [ + { + "bbox": [ + 46, + 308, + 289, + 538 + ], + "type": "text", + "content": "In Table 7, prediction-related modules in STIP [4] and SimVP [12] handle both motion and appearance features. However, in MMVP, prediction-related modules specifically handle only the motion features, leaving all appearance features to the content encoder and decoder. The most noticeable fact from Table 7 is that in STIP [4] and SimVP [12], the prediction-related modules take majority of the model parameters (the ratios are " + }, + { + "bbox": [ + 46, + 308, + 289, + 538 + ], + "type": "inline_equation", + "content": "99.7\\%" + }, + { + "bbox": [ + 46, + 308, + 289, + 538 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 308, + 289, + 538 + ], + "type": "inline_equation", + "content": "99.4\\%" + }, + { + "bbox": [ + 46, + 308, + 289, + 538 + ], + "type": "text", + "content": " respectively). In contrast, motion-related modules in MMVP only take " + }, + { + "bbox": [ + 46, + 308, + 289, + 538 + ], + "type": "inline_equation", + "content": "14.5\\%" + }, + { + "bbox": [ + 46, + 308, + 289, + 538 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 308, + 289, + 538 + ], + "type": "inline_equation", + "content": "15.9\\%" + }, + { + "bbox": [ + 46, + 308, + 289, + 538 + ], + "type": "text", + "content": " of the parameters. This fact supports our argument in Sec. 1 that decoupling motion prediction and appearance maintenance effectively avoid the cumbersome structures of the prediction modules and largely improve the prediction efficiency. Another observation is that despite the small size, the prediction-related modules in MMVP can still support high-quality motion prediction. This validates the efficiency of the motion matrices when describing the motion information, which results in a lightweight design of the prediction module." + } + ] + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 48, + 594, + 286, + 642 + ], + "blocks": [ + { + "bbox": [ + 47, + 548, + 287, + 584 + ], + "lines": [ + { + "bbox": [ + 47, + 548, + 287, + 584 + ], + "spans": [ + { + "bbox": [ + 47, + 548, + 287, + 584 + ], + "type": "text", + "content": "Table 7: Model size breakdown. The numerical values are the number of parameters taken by each component in the video prediction systems." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 594, + 286, + 642 + ], + "lines": [ + { + "bbox": [ + 48, + 594, + 286, + 642 + ], + "spans": [ + { + "bbox": [ + 48, + 594, + 286, + 642 + ], + "type": "table", + "html": "
MethodContent EncoderPrediction ModulesContent DecoderTotal
STIPHR [4]29.86K17994.8K29.54K18054.2K
SimVP [12]7.5k3447.1K11.7K3466.3K
MMVP-mini369.4K113.2K228.3K710.9K
MMVP1472.2K404.9K911.9K2789.0K
", + "image_path": "45d1cf62ad8d13030c6f17e1e1edc73a4fd3b7c7502833a2ac673f854237656d.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 669, + 120, + 681 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 669, + 120, + 681 + ], + "spans": [ + { + "bbox": [ + 47, + 669, + 120, + 681 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 689, + 287, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 287, + 712 + ], + "type": "text", + "content": "The proposed Motion-Matrix-based Video Prediction framework (MMVP) is an end-to-end trainable two-stream" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 72, + 547, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 205 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 205 + ], + "type": "text", + "content": "pipeline. MMVP uses motion matrices to represent appearance-agnostic motion patterns. As the sole input of the motion prediction module in MMVP, the motion matrix can i) describe the many-to-many relationships between feature patches without training for extra modules; ii) intuitively compose future features with multi-scale image features through matrix multiplication. It helps the motion prediction become more focused, and efficiently reduces the information loss in appearance. Extensive experiments demonstrate the superiority of MMVP compared to existing SOTA methods in both the model size and performance." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 307, + 217, + 365, + 228 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 217, + 365, + 228 + ], + "spans": [ + { + "bbox": [ + 307, + 217, + 365, + 228 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 307, + 236, + 547, + 714 + ], + "type": "list", + "angle": 0, + "index": 20, + "blocks": [ + { + "bbox": [ + 310, + 236, + 547, + 280 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 236, + 547, + 280 + ], + "spans": [ + { + "bbox": [ + 310, + 236, + 547, + 280 + ], + "type": "text", + "content": "[1] Mohammad Babaeizadeh, Chelsea Finn, Dumitru Erhan, Roy H Campbell, and Sergey Levine. Stochastic variational video prediction. arXiv preprint arXiv:1710.11252, 2017. 7, 8" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 311, + 282, + 547, + 327 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 282, + 547, + 327 + ], + "spans": [ + { + "bbox": [ + 311, + 282, + 547, + 327 + ], + "type": "text", + "content": "[2] Xinzhu Bei, Yanchao Yang, and Stefano Soatto. Learning semantic-aware dynamics for video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 902-912, 2021. 2, 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 311, + 328, + 547, + 382 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 328, + 547, + 382 + ], + "spans": [ + { + "bbox": [ + 311, + 328, + 547, + 382 + ], + "type": "text", + "content": "[3] Po-Rong Chang and Jen-Tsung Hu. Optimal nonlinear adaptive prediction and modeling ofmpeg video in atm networks using pipelined recurrent neural networks. IEEE Journal on Selected Areas in Communications, 15(6):1087-1100, 1997. 1" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 311, + 384, + 547, + 440 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 384, + 547, + 440 + ], + "spans": [ + { + "bbox": [ + 311, + 384, + 547, + 440 + ], + "type": "text", + "content": "[4] Zheng Chang, Xinfeng Zhang, Shanshe Wang, Siwei Ma, and Wen Gao. Stip: A spatiotemporal information-preserving and perception-augmented model for high-resolution video prediction. arXiv preprint arXiv:2206.04381, 2022. 1, 2, 3, 5, 6, 7, 8, 9" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 311, + 441, + 547, + 506 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 441, + 547, + 506 + ], + "spans": [ + { + "bbox": [ + 311, + 441, + 547, + 506 + ], + "type": "text", + "content": "[5] Zheng Chang, Xinfeng Zhang, Shanshe Wang, Siwei Ma, and Wen Gao. Strpm: A spatiotemporal residual predictive model for high-resolution video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13946-13955, 2022. 1, 2, 3, 5, 6, 8" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 311, + 508, + 547, + 542 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 508, + 547, + 542 + ], + "spans": [ + { + "bbox": [ + 311, + 508, + 547, + 542 + ], + "type": "text", + "content": "[6] Emily L Denton et al. Unsupervised learning of disentangled representations from video. Advances in neural information processing systems, 30, 2017. 2, 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 311, + 544, + 547, + 587 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 544, + 547, + 587 + ], + "spans": [ + { + "bbox": [ + 311, + 544, + 547, + 587 + ], + "type": "text", + "content": "[7] Duarte Duque, Henrique Santos, and Paulo Cortez. Prediction of abnormal behaviors for intelligent video surveillance systems. In 2007 IEEE Symposium on Computational Intelligence and Data Mining, pages 362-367. IEEE, 2007. 1" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 311, + 589, + 547, + 633 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 589, + 547, + 633 + ], + "spans": [ + { + "bbox": [ + 311, + 589, + 547, + 633 + ], + "type": "text", + "content": "[8] Frederik Ebert, Chelsea Finn, Sudeep Dasari, Annie Xie, Alex Lee, and Sergey Levine. Visual foresight: Model-based deep reinforcement learning for vision-based robotic control. arXiv preprint arXiv:1812.00568, 2018. 1" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 311, + 635, + 547, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 635, + 547, + 678 + ], + "spans": [ + { + "bbox": [ + 311, + 635, + 547, + 678 + ], + "type": "text", + "content": "[9] Chelsea Finn and Sergey Levine. Deep visual foresight for planning robot motion. In 2017 IEEE International Conference on Robotics and Automation (ICRA), pages 2786-2793. IEEE, 2017. 1" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 680, + 547, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 680, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 307, + 680, + 547, + 714 + ], + "type": "text", + "content": "[10] Hang Gao, Huazhe Xu, Qi-Zhi Cai, Ruth Wang, Fisher Yu, and Trevor Darrell. Disentangling propagation and generation for video prediction. In Proceedings of the IEEE/CVF" + } + ] + } + ], + "index": 19 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 314, + 757 + ], + "type": "text", + "content": "4281" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 73, + 287, + 714 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 67, + 73, + 287, + 94 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 73, + 287, + 94 + ], + "spans": [ + { + "bbox": [ + 67, + 73, + 287, + 94 + ], + "type": "text", + "content": "international conference on computer vision, pages 9006-9015, 2019. 2, 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 95, + 287, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 95, + 287, + 149 + ], + "spans": [ + { + "bbox": [ + 48, + 95, + 287, + 149 + ], + "type": "text", + "content": "[11] Xiaojie Gao, Yueming Jin, Qi Dou, Chi-Wing Fu, and Pheng-Ann Heng. Accurate grid keypoint learning for efficient video prediction. In 2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages 5908–5915. IEEE, 2021. 2, 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 150, + 287, + 204 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 150, + 287, + 204 + ], + "spans": [ + { + "bbox": [ + 48, + 150, + 287, + 204 + ], + "type": "text", + "content": "[12] Zhangyang Gao, Cheng Tan, Lirong Wu, and Stan Z Li. Simvp: Simpler yet better video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3170-3180, 2022. 1, 2, 5, 6, 7, 8, 9" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 205, + 287, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 205, + 287, + 239 + ], + "spans": [ + { + "bbox": [ + 48, + 205, + 287, + 239 + ], + "type": "text", + "content": "[13] Bernd Girod. The efficiency of motion-compensating prediction for hybrid coding of video sequences. IEEE Journal on selected areas in communications, 5(7):1140-1154, 1987. 1" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 239, + 287, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 239, + 287, + 293 + ], + "spans": [ + { + "bbox": [ + 48, + 239, + 287, + 293 + ], + "type": "text", + "content": "[14] Vincent Le Guen and Nicolas Thome. Disentangling physical dynamics from unknown factors for unsupervised video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11474-11484, 2020. 8" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 293, + 287, + 337 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 293, + 287, + 337 + ], + "spans": [ + { + "bbox": [ + 48, + 293, + 287, + 337 + ], + "type": "text", + "content": "[15] Agrim Gupta, Stephen Tian, Yunzhi Zhang, Jiajun Wu, Roberto Martín-Martín, and Li Fei-Fei. Maskvit: Masked visual pre-training for video prediction. arXiv preprint arXiv:2206.11894, 2022.3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 338, + 287, + 381 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 338, + 287, + 381 + ], + "spans": [ + { + "bbox": [ + 48, + 338, + 287, + 381 + ], + "type": "text", + "content": "[16] Noriaki Hirose, Fei Xia, Roberto Martín-Martín, Amir Sadeghian, and Silvio Savarese. Deep visual mpc-policy learning for navigation. IEEE Robotics and Automation Letters, 4(4):3184-3191, 2019. 1" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 382, + 287, + 404 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 382, + 287, + 404 + ], + "spans": [ + { + "bbox": [ + 48, + 382, + 287, + 404 + ], + "type": "text", + "content": "[17] Berthold KP Horn and Brian G Schunck. Determining optical flow. Artificial intelligence, 17(1-3):185–203, 1981. 4" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 404, + 287, + 448 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 404, + 287, + 448 + ], + "spans": [ + { + "bbox": [ + 48, + 404, + 287, + 448 + ], + "type": "text", + "content": "[18] Jun-Ting Hsieh, Bingbin Liu, De-An Huang, Li F Fei-Fei, and Juan Carlos Niebles. Learning to decompose and disentangle representations for video prediction. Advances in neural information processing systems, 31, 2018. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 449, + 287, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 449, + 287, + 491 + ], + "spans": [ + { + "bbox": [ + 48, + 449, + 287, + 491 + ], + "type": "text", + "content": "[19] Xiaotao Hu, Zhewei Huang, Ailin Huang, Jun Xu, and Shuchang Zhou. A dynamic multi-scale voxel flow network for video prediction. arXiv preprint arXiv:2303.09875, 2023. 8" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 492, + 287, + 525 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 492, + 287, + 525 + ], + "spans": [ + { + "bbox": [ + 48, + 492, + 287, + 525 + ], + "type": "text", + "content": "[20] Xu Jia, Bert De Brabandere, Tinne Tuytelaars, and Luc V Gool. Dynamic filter networks. Advances in neural information processing systems, 29, 2016. 7" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 525, + 287, + 592 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 525, + 287, + 592 + ], + "spans": [ + { + "bbox": [ + 48, + 525, + 287, + 592 + ], + "type": "text", + "content": "[21] Beibei Jin, Yu Hu, Qiankun Tang, Jingyu Niu, Zhiping Shi, Yinhe Han, and Xiaowei Li. Exploring spatial-temporal multi-frequency analysis for high-fidelity and temporal-consistency video prediction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4554-4563, 2020. 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 592, + 287, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 592, + 287, + 646 + ], + "spans": [ + { + "bbox": [ + 48, + 592, + 287, + 646 + ], + "type": "text", + "content": "[22] Beibei Jin, Yu Hu, Yiming Zeng, Qiankun Tang, Shice Liu, and Jing Ye. Varnet: Exploring variations for unsupervised video prediction. In 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages 5801-5806. IEEE, 2018. 7" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 647, + 287, + 691 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 287, + 691 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 287, + 691 + ], + "type": "text", + "content": "[23] Nal Kalchbrenner, Aäron Oord, Karen Simonyan, Ivo Danihelka, Oriol Vinyals, Alex Graves, and Koray Kavukcuoglu. Video pixel networks. In International Conference on Machine Learning, pages 1771-1779. PMLR, 2017. 3, 7" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "type": "text", + "content": "[24] Yong-Hoon Kwon and Min-Gyu Park. Predicting future frames using retrospective cycle gan. In Proceedings of" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "text", + "content": "the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1811-1820, 2019. 8" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 95, + 545, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 95, + 545, + 139 + ], + "spans": [ + { + "bbox": [ + 307, + 95, + 545, + 139 + ], + "type": "text", + "content": "[25] Alex X Lee, Richard Zhang, Frederik Ebert, Pieter Abbeel, Chelsea Finn, and Sergey Levine. Stochastic adversarial video prediction. arXiv preprint arXiv:1804.01523, 2018. 7, 8" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 141, + 545, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 141, + 545, + 184 + ], + "spans": [ + { + "bbox": [ + 307, + 141, + 545, + 184 + ], + "type": "text", + "content": "[26] Jungbeom Lee, Jangho Lee, Sungmin Lee, and Sungroh Yoon. Mutual suppression network for video prediction using disentangled features. arXiv preprint arXiv:1804.04810, 2018. 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 186, + 545, + 230 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 186, + 545, + 230 + ], + "spans": [ + { + "bbox": [ + 307, + 186, + 545, + 230 + ], + "type": "text", + "content": "[27] Xiaodan Liang, Lisa Lee, Wei Dai, and Eric P Xing. Dual motion gan for future-flow embedded video prediction. In proceedings of the IEEE international conference on computer vision, pages 1744-1752, 2017. 2, 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 232, + 545, + 275 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 232, + 545, + 275 + ], + "spans": [ + { + "bbox": [ + 308, + 232, + 545, + 275 + ], + "type": "text", + "content": "[28] Jianping Lin, Dong Liu, Houqiang Li, and Feng Wu. M-lvc: Multiple frames prediction for learned video compression. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3546-3554, 2020. 1" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 276, + 545, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 276, + 545, + 330 + ], + "spans": [ + { + "bbox": [ + 308, + 276, + 545, + 330 + ], + "type": "text", + "content": "[29] Bowen Liu, Yu Chen, Shiyu Liu, and Hun-Seok Kim. Deep learning in latent space for video prediction and compression. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 701-710, 2021. 1" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 332, + 545, + 365 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 332, + 545, + 365 + ], + "spans": [ + { + "bbox": [ + 308, + 332, + 545, + 365 + ], + "type": "text", + "content": "[30] Michael Mathieu, Camille Couprie, and Yann LeCun. Deep multi-scale video prediction beyond mean square error. arXiv preprint arXiv:1511.05440, 2015. 8" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 366, + 545, + 409 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 366, + 545, + 409 + ], + "spans": [ + { + "bbox": [ + 308, + 366, + 545, + 409 + ], + "type": "text", + "content": "[31] Tomas Mikolov, Martin Karafiát, Lukas Burget, Jan Cernocký, and Sanjeev Khudanpur. Recurrent neural network based language model. In *Interspeech*, volume 2, pages 1045–1048. Makuhari, 2010. 1" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 411, + 545, + 455 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 411, + 545, + 455 + ], + "spans": [ + { + "bbox": [ + 308, + 411, + 545, + 455 + ], + "type": "text", + "content": "[32] Marc Oliu, Javier Selva, and Sergio Escalera. Folded recurrent neural networks for future video prediction. In Proceedings of the European Conference on Computer Vision (ECCV), pages 716-731, 2018. 7" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 456, + 545, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 456, + 545, + 521 + ], + "spans": [ + { + "bbox": [ + 308, + 456, + 545, + 521 + ], + "type": "text", + "content": "[33] Sergiu Oprea, Pablo Martinez-Gonzalez, Alberto Garcia-Garcia, John Alejandro Castro-Vargas, Sergio Orts-Escalano, Jose Garcia-Rodriguez, and Antonis Argyros. A review on deep learning techniques for video prediction. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(6):2806-2826, 2020. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 523, + 545, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 523, + 545, + 588 + ], + "spans": [ + { + "bbox": [ + 308, + 523, + 545, + 588 + ], + "type": "text", + "content": "[34] F. Pedregosa, G. Varoquaux, A. Gramfort, V. Michel, B. Thirion, O. Grisel, M. Blondel, P. Prettenhofer, R. Weiss, V. Dubourg, J. Vanderplas, A. Passos, D. Cournaepau, M. Brucher, M. Perrot, and E. Duchesnay. Scikit-learn: Machine learning in Python. Journal of Machine Learning Research, 12:2825-2830, 2011. 6" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 590, + 545, + 623 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 590, + 545, + 623 + ], + "spans": [ + { + "bbox": [ + 308, + 590, + 545, + 623 + ], + "type": "text", + "content": "[35] Ruslan Rakhimov, Denis Volkhonskiy, Alexey Artemov, Denis Zorin, and Evgeny Burnaev. Latent video transformer. arXiv preprint arXiv:2006.10704, 2020. 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 624, + 545, + 677 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 624, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 308, + 624, + 545, + 677 + ], + "type": "text", + "content": "[36] Mikel D Rodriguez, Javed Ahmed, and Mubarak Shah. Action mach a spatio-temporal maximum average correlation height filter for action recognition. In 2008 IEEE conference on computer vision and pattern recognition, pages 1-8. IEEE, 2008. 2, 5" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 680, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 680, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 680, + 545, + 713 + ], + "type": "text", + "content": "[37] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image com" + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "4282" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 66, + 72, + 286, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 286, + 95 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 286, + 95 + ], + "type": "text", + "content": "puting and computer-assisted intervention, pages 234-241. Springer, 2015. 5" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 140 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 140 + ], + "type": "text", + "content": "[38] Christian Schuldt, Ivan Laptev, and Barbara Caputo. Recognizing human actions: a localsvm approach. In Proceedings of the 17th International Conference on Pattern Recognition, 2004.ICPR 2004., volume 3,pages 32-36.IEEE,2004.2,5" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 141, + 288, + 207 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 141, + 288, + 207 + ], + "spans": [ + { + "bbox": [ + 48, + 141, + 288, + 207 + ], + "type": "text", + "content": "[39] Wenzhe Shi, Jose Caballero, Ferenc Huszár, Johannes Totz, Andrew P Aitken, Rob Bishop, Daniel Rueckert, and Zehan Wang. Real-time single image and video super-resolution using an efficient sub-pixel convolutional neural network. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1874-1883, 2016. 5" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 209, + 287, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 209, + 287, + 262 + ], + "spans": [ + { + "bbox": [ + 48, + 209, + 287, + 262 + ], + "type": "text", + "content": "[40] Xingjian Shi, Zhourong Chen, Hao Wang, Dit-Yan Yeung, Wai-Kin Wong, and Wang-chun Woo. Convolutional LSTM network: A machine learning approach for precipitation nowcasting. Advances in neural information processing systems, 28, 2015. 3, 7, 8" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 264, + 287, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 264, + 287, + 308 + ], + "spans": [ + { + "bbox": [ + 48, + 264, + 287, + 308 + ], + "type": "text", + "content": "[41] Nitish Srivastava, Elman Mansimov, and Ruslan Salakhudinov. Unsupervised learning of video representations using lstms. In International conference on machine learning, pages 843-852. PMLR, 2015. 2, 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 310, + 287, + 354 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 310, + 287, + 354 + ], + "spans": [ + { + "bbox": [ + 48, + 310, + 287, + 354 + ], + "type": "text", + "content": "[42] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. 1, 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 355, + 287, + 398 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 355, + 287, + 398 + ], + "spans": [ + { + "bbox": [ + 48, + 355, + 287, + 398 + ], + "type": "text", + "content": "[43] Ruben Villegas, Jimei Yang, Seunghoon Hong, Xunyu Lin, and Honglak Lee. Decomposing motion and content for natural video sequence prediction. arXiv preprint arXiv:1706.08033, 2017. 2, 3, 5, 7" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 399, + 287, + 455 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 399, + 287, + 455 + ], + "spans": [ + { + "bbox": [ + 48, + 399, + 287, + 455 + ], + "type": "text", + "content": "[44] Xintao Wang, Ke Yu, Shixiang Wu, Jinjin Gu, Yihao Liu, Chao Dong, Yu Qiao, and Chen Change Loy. Esrgan: Enhanced super-resolution generative adversarial networks. In Proceedings of the European conference on computer vision (ECCV) workshops, pages 0–0, 2018. 3, 4, 5" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 456, + 287, + 511 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 456, + 287, + 511 + ], + "spans": [ + { + "bbox": [ + 48, + 456, + 287, + 511 + ], + "type": "text", + "content": "[45] Yunbo Wang, Zhifeng Gao, Mingsheng Long, Jianmin Wang, and S Yu Philip. Predrnn++: Towards a resolution of the deep-in-time dilemma in spatiotemporal predictive learning. In International Conference on Machine Learning, pages 5123-5132. PMLR, 2018. 1, 2, 3, 7, 8" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 512, + 287, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 512, + 287, + 555 + ], + "spans": [ + { + "bbox": [ + 48, + 512, + 287, + 555 + ], + "type": "text", + "content": "[46] Yunbo Wang, Lu Jiang, Ming-Hsuan Yang, Li-Jia Li, Mingsheng Long, and Li Fei-Fei. Eidetic 3d LSTM: A model for video prediction and beyond. In International conference on learning representations, 2018. 1, 2, 3, 5, 7, 8" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 557, + 287, + 610 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 557, + 287, + 610 + ], + "spans": [ + { + "bbox": [ + 48, + 557, + 287, + 610 + ], + "type": "text", + "content": "[47] Yunbo Wang, Mingsheng Long, Jianmin Wang, Zhifeng Gao, and Philip S Yu. Predrnn: Recurrent neural networks for predictive learning using spatiotemporal lstms. Advances in neural information processing systems, 30, 2017. 1, 2, 3, 7, 8" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 613, + 287, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 613, + 287, + 668 + ], + "spans": [ + { + "bbox": [ + 48, + 613, + 287, + 668 + ], + "type": "text", + "content": "[48] Yunbo Wang, Haixu Wu, Jianjin Zhang, Zhifeng Gao, Jian-min Wang, Philip Yu, and Mingsheng Long. Predrnn: A recurrent neural network for spatiotemporal predictive learning. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 8" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "type": "text", + "content": "[49] Yunbo Wang, Jianjin Zhang, Hongyu Zhu, Mingsheng Long, Jianmin Wang, and Philip S Yu. Memory in memory: A predictive neural network for learning higher-order nonstationarity from spatiotemporal dynamics. In Proceedings" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 543 + ], + "type": "list", + "angle": 0, + "index": 25, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "text", + "content": "of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9154-9162, 2019. 8" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 308, + 96, + 545, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 96, + 545, + 128 + ], + "spans": [ + { + "bbox": [ + 308, + 96, + 545, + 128 + ], + "type": "text", + "content": "[50] Dirk Weissenborn, Oscar Täckström, and Jakob Uszkoreit. Scaling autoregressive video models. arXiv preprint arXiv:1906.02634, 2019. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 130, + 547, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 130, + 547, + 184 + ], + "spans": [ + { + "bbox": [ + 307, + 130, + 547, + 184 + ], + "type": "text", + "content": "[51] Haixu Wu, Zhiyu Yao, Jianmin Wang, and Mingsheng Long. Motionrnn: A flexible model for video prediction with spacetime-varying motions. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 15435-15444, 2021. 8" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 186, + 547, + 229 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 186, + 547, + 229 + ], + "spans": [ + { + "bbox": [ + 308, + 186, + 547, + 229 + ], + "type": "text", + "content": "[52] Yue Wu, Qiang Wen, and Qifeng Chen. Optimizing video prediction via video frame interpolation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 17814-17823, 2022. 2, 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 231, + 545, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 231, + 545, + 274 + ], + "spans": [ + { + "bbox": [ + 308, + 231, + 545, + 274 + ], + "type": "text", + "content": "[53] Ren Yang, Radu Timofte, and Luc Van Gool. Advancing learned video compression with in-loop frame prediction. IEEE Transactions on Circuits and Systems for Video Technology, 2022. 1" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 276, + 545, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 276, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 308, + 276, + 545, + 308 + ], + "type": "text", + "content": "[54] Wei Yu, Yichao Lu, Steve Easterbrook, and Sanja Fidler. Crevnet: Conditionally reversible video prediction. arXiv preprint arXiv:1910.11577, 2019. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 309, + 545, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 309, + 545, + 342 + ], + "spans": [ + { + "bbox": [ + 308, + 309, + 545, + 342 + ], + "type": "text", + "content": "[55] Wei Yu, Yichao Lu, Steve Easterbrook, and Sanja Fidler. Efficient and information-preserving future frame prediction and beyond. 2020. 1, 8" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 343, + 545, + 396 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 343, + 545, + 396 + ], + "spans": [ + { + "bbox": [ + 308, + 343, + 545, + 396 + ], + "type": "text", + "content": "[56] Jianjin Zhang, Yunbo Wang, Mingsheng Long, Wang Jian-min, and S Yu Philip. Z-order recurrent neural networks for video prediction. In 2019 IEEE International Conference on Multimedia and Expo (ICME), pages 230-235. IEEE, 2019. 7" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 399, + 545, + 442 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 399, + 545, + 442 + ], + "spans": [ + { + "bbox": [ + 308, + 399, + 545, + 442 + ], + "type": "text", + "content": "[57] Qianqian Zhang, Guorui Feng, and Hanzhou Wu. Surveillance video anomaly detection via non-local u-net frame prediction. Multimedia Tools and Applications, 81(19):27073-27088, 2022. 1" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 444, + 545, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 444, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 308, + 444, + 545, + 498 + ], + "type": "text", + "content": "[58] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 586-595, 2018. 6" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 499, + 545, + 543 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 499, + 545, + 543 + ], + "spans": [ + { + "bbox": [ + 308, + 499, + 545, + 543 + ], + "type": "text", + "content": "[59] Xianguo Zhang, Tiejun Huang, Yonghong Tian, and Wen Gao. Background-modeling-based adaptive prediction for surveillance video coding. IEEE Transactions on Image Processing, 23(2):769-784, 2013. 1" + } + ] + } + ], + "index": 24 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "4283" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/cd6d82fe-3030-4ffc-8902-e0f3febe9ace_content_list.json b/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/cd6d82fe-3030-4ffc-8902-e0f3febe9ace_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..62d3eecf21a2e646e82f99fb87a73daad8e37df1 --- /dev/null +++ b/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/cd6d82fe-3030-4ffc-8902-e0f3febe9ace_content_list.json @@ -0,0 +1,1590 @@ +[ + { + "type": "text", + "text": "MODA: Mapping-Once Audio-driven Portrait Animation with Dual Attentions", + "text_level": 1, + "bbox": [ + 86, + 130, + 883, + 154 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Yunfei Liu1 Lijian Lin1 Fei Yu2 Changyin Zhou2 Yu Li1* 1International Digital Economy Academy (IDEA) 2Vstring Inc. https://tinyurl.com/iccv23-modala", + "bbox": [ + 181, + 178, + 785, + 233 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/bbaaec040456d9d6ae7cce19783479400bdfff4903c90b1a381964923e40ffa0.jpg", + "image_caption": [ + "Figure 1: We propose a mapping-once system with dual-attention for multimodal and high-fidelity portrait video animation." + ], + "image_footnote": [], + "bbox": [ + 98, + 273, + 874, + 494 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 527, + 313, + 542 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Audio-driven portrait animation aims to synthesize portrait videos that are conditioned by given audio. Animating high-fidelity and multimodal video portraits has a variety of applications. Previous methods have attempted to capture different motion modes and generate high-fidelity portrait videos by training different models or sampling signals from given videos. However, lacking correlation learning between lip-sync and other movements (e.g., head pose/eye blinking) usually leads to unnatural results. In this paper, we propose a unified system for multi-person, diverse, and high-fidelity talking portrait generation. Our method contains three stages, i.e., 1) Mapping-Once network with Dual Attentions (MODA) generates talking representation from given audio. In MODA, we design a dual-attention module to encode accurate mouth movements and diverse modalities. 2) Facial composer network generates dense and detailed face landmarks, and 3) temporal-guided renderer syntheses stable videos. Extensive evaluations demonstrate that the proposed system produces more natural and realistic video portraits compared to previous methods.", + "bbox": [ + 75, + 559, + 473, + 863 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 501, + 527, + 630, + 542 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Given an input audio, talking portrait animation is to synthesize video frames of a person whose poses and expressions are synchronized with the audio signal [2, 3, 4, 18]. This audio-driven portrait video generation task has gained increasing attention recently and has a wide range of applications in digital avatars, gaming, telepresence, virtual reality (VR), video production etc. Conventional portrait video generation consumes intensive labor and time during setting up the background, make-up, lighting, shooting, and editing. Moreover, a re-shot is always required when there exists new textual content. In contrast, audio-driven talking video generation is more convenient and attractive which only requires a new audio clip to render a new video.", + "bbox": [ + 496, + 553, + 890, + 748 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Previous methods [7, 29, 52] try to learn the correspondence between audio and frames. However, these methods usually ignore the head pose as it is hard to separate head posture from facial movement. Many 3D face reconstruction algorithm-based and GAN-based [8] methods estimate intermediate representations, such as 3D face shapes [6, 50], 2D landmarks [22, 54], or face expression parameters [49], to assist the generation process. However, such sparse representations usually lost facial details, leading to over-smooth [44]. Recently, the neural radiance field", + "bbox": [ + 496, + 750, + 892, + 900 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding author.", + "bbox": [ + 94, + 886, + 220, + 898 + ], + "page_idx": 0 + }, + { + "type": "footer", + "text": "23020", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "(NeRF) [10, 44] has been widely applied in talking head generation for high-fidelity results. However, the implicit neural representation is hard to interpret and control. In addition, these methods are usually person-specific and require extra training or adaptation time for different persons.", + "bbox": [ + 75, + 90, + 468, + 167 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Although quite a number of attempts and progresses have been made in recent years, it is still challenging to generate realistic and expressive talking videos. As humans are extremely sensitive to identifying the artifacts in the synthesized portrait videos, it sets a very high standard for this technique to become applicable. We summarize the following key points that affect human perceptions: 1) Correctness. The synthesized talking portrait video should be well synchronized with the driven audio. 2) Visual quality. The synthesized video should have high resolution and contain fine detail components. 3) Diversity. Besides the lip motion needing to be exactly matched to the audio content, the motion of other components like eye blinking and head movement are not deterministic. They should move naturally as a natural human does.", + "bbox": [ + 75, + 171, + 472, + 398 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To achieve these goals, previous approaches either map the mouth landmarks and the head pose separately by learning different sub-networks [22, 50], or only model the mouth movement while the head pose is obtained from the existing video [29, 52]. However, lacking correlation learning between lip-sync and other movements usually leads to unnatural results. In this paper, we propose a mapping-once network with dual attentions (MODA), which is a unified architecture to generate diverse representations for a talking portrait, simplifying the computational steps. In order to combine synchronization and diversity of the talking portrait generation, we carefully design a dual-attention module to learn deterministic mappings (i.e., the accurate mouth movements driven by audio) and probabilistic sampling (i.e., the diverse head pose/eye blinking from time-to-time), respectively. To summarize, our contributions can be listed as follows:", + "bbox": [ + 75, + 402, + 472, + 659 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose a talking portrait system that generates multimodal photorealistic portrait videos with accurate lip motion. Comprehensive evaluations demonstrate our system can achieve state-of-the-art performance.", + "- We propose a unified mapping-once with dual attention (MODA) network for generating portrait representation from subject conditions and arbitrary audio.", + "- We propose 3 technical points for taking portrait generation: 1) A transformer-based dual attention module for generating both specific and diverse representations. 2) A facial composer network to get accurate and detailed facial landmarks. 3) A temporally guided renderer to synthesize videos with both high quality and temporal stabilization." + ], + "bbox": [ + 96, + 674, + 467, + 888 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Works", + "text_level": 1, + "bbox": [ + 500, + 89, + 650, + 106 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Audio-driven portrait animation. Talking heads and facial animation are research hot-spots in the computer vision community. Extensive approaches [5, 55] explore audio-driven mouth animation and audio-driven facial animation. We focus on animating a portrait in this work. Many methods [4, 5, 29, 31, 56] aim to find the correspondence between audio and frames. A large number of technologies (such as flow-learning [14, 40, 51], memory bank [25, 35], etc.) are explored for the correctness of talking head generation. However, these methods usually ignore the head pose, torso motion, and eye blinking, which are essential for a natural talking portrait generation. To generate diverse talking heads, recent methods [19, 52] propose to embed other modalities to control emotions or head pose. However, these methods usually require additional inputs.", + "bbox": [ + 496, + 114, + 890, + 340 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Recently, neural radiance field (NeRF) [10] has been widely applied in 3D-related tasks as it can accurately reproduce complex scenes with implicit neural representation. Several works [10, 43, 21, 44] leverage NeRF to represent faces with audio features as conditions. Despite the high-quality results achieved, the motion of generated results is usually unnatural. Besides, the learning and inference processes are time-consuming. More recently, some diffusion-based methods [32, 34] are proposed to generate talking heads. However, their speed is limited by a large number of sampling steps in the diffusion process. Some methods are based on the 3D face reconstruction and GAN [15, 22, 45]. They estimate intermediate representations such as 2D landmarks [39, 48, 54], 3D face shapes [15, 36] or facial expression parameters [42, 50], to assist the generation process. Unfortunately, such sparse representation usually lost facial details. In this paper, we propose to learn dense facial landmarks and upper body points through a unified framework for talking portrait generation. The intermediate representation contains facial details and other movements, which can be interpreted and controlled easily.", + "bbox": [ + 496, + 340, + 892, + 657 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Transformers in audio-driven tasks. Transformer [38] is a strong alternative to both RNN and CNN. Researchers find it works well in multimodal scenarios. We refer readers to the comprehensive survey [16] for further information. Some recent works adopt transformers to generate results from different modalities, such as audio-to-text, language translation, music-to-dance, etc. The most related work is FaceFormer [6], which is a speech-driven 3D facial animation approach. They proposed two types of bias for the transformer to better align audio and 3D face animation.", + "bbox": [ + 496, + 659, + 890, + 809 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Vision-based facial reenactment. Video-based facial reenactment is another technique related to audio-driven animation [33, 31]. There are many works to reenact faces with different techniques, such as adversarial learning, few-shot learning, or even one-shot facial animation. They usually adopt pre-defined facial landmarks or in an unsupervised", + "bbox": [ + 496, + 810, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "23021", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/e2a46c4d52521b48a864f66a273f9e15275813ec0d466a2e1f4c70456137f8b3.jpg", + "image_caption": [ + "Figure 2: The proposed method is a three-stage system. Given the subject figure and arbitrary audio, the proposed system generates audio-driven video. Here $\\mathbb{O}$ denotes rigid transformation from canonical space to camera coordinate via head pose, $\\odot$ denotes concatenation. $\\mathbb{P}$ is projection from 3D space to image coordinate. FaCo-Net is a facial composer network, which will be introduced in Sec. 3.3." + ], + "image_footnote": [], + "bbox": [ + 89, + 85, + 893, + 212 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "scheme. In another aspect, image-to-image translation (I2I) methods [20, 46] have also demonstrated impressive performance in converting images from one domain to another. However, single-frame renderers [20] ignore the temporal relations among video frames, leading to color jitters or unnatural background shakes in the final results. [41] proposes to use RNN [23] to capture the temporal relations among the input conditions, which generates stabilized results. However, these methods have difficulties in training [26]. In this paper, we find an alternative way to embed temporal information into I2I. Simply using temporal positional embedding [11] as an input condition, our method can achieve natural and stabilized results.", + "bbox": [ + 75, + 290, + 472, + 487 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Methodology", + "text_level": 1, + "bbox": [ + 76, + 503, + 212, + 522 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We present a talking portrait system for high-fidelity portrait video generation with accurate lip motion and multimodal motions, including head pose, eye blinking, and torso movements. The overall pipeline of this system is illustrated in Fig. 2. It contains three stages, 1) given the driven audio and conditioned subjects, mapping once talking portrait network with dual attentions (MODA) generates multimodal and correct semantic portrait components, 2) in the next, the facial composer network combines the facial components together and adds details for dense facial vertices, and 3) finally, a portrait renderer with temporally positional embedding (TPE) syntheses high-fidelity and stable videos.", + "bbox": [ + 75, + 530, + 468, + 712 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Task Definition", + "text_level": 1, + "bbox": [ + 76, + 724, + 230, + 739 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this section, we give the definition of the talking portrait task, which is to formulate a sequence-to-sequence translation manner [1] from talking portrait videos. Specifically, given a $T$ -length audio sequence $\\mathbf{A} = \\{a_0, a_1, \\dots, a_T\\}$ with audio sampling rate $r$ , a talking portrait method aims to map it into the corresponding video clip $\\mathbf{V} = \\{I_0, I_1, \\dots, I_K\\}$ with $f$ frame-per-second (FPS), where $K = \\lfloor fT / r \\rfloor$ . Since the data dimension of $\\mathbf{V}$ is much larger than $\\mathbf{A}$ , many researchers propose to generate $\\mathbf{V}$ progressively and introduce many types of intermediate", + "bbox": [ + 75, + 750, + 470, + 901 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "representation $\\mathbf{R}$ . To make the generated $\\mathbf{V}$ look natural, the constraint on $\\mathbf{R}$ is critical. In previous audio-driven face animation approaches, $\\mathbf{R}$ typically represents one type of face information, such as facial landmarks [22, 54] or head pose [50]. To better represent a talking portrait, we define $\\mathbf{R}$ as the union of different portrait descriptors, i.e., $\\mathbf{R} = \\{P^M, P^E, P^F, H, P^T\\}$ , where the elements of $\\mathbf{R}$ are defined as follows,", + "bbox": [ + 496, + 290, + 890, + 410 + ], + "page_idx": 2 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1. Mouth points $P^M \\in \\mathbb{R}^{40 \\times 3}$ . They have 40 points for representing mouth animation.", + "2. Eyes points $P^{E} \\in \\mathbb{R}^{60 \\times 3}$ . They consist of eye and eyebrow points, which control eye blinking.", + "3. Facial points $P^{F} \\in \\mathbb{R}^{478 \\times 3}$ . They contain dense facial 3D points for recording expression details.", + "4. Head pose $H \\in \\mathbb{R}^6$ . It contains head rotations $(\\theta, \\phi, \\psi)$ in Euler angle and head transposes $(x, y, z)$ in Euclidean space).", + "5. Torso points $P^T \\in \\mathbb{R}^{18 \\times 3}$ . They contain 18 points and each side of the shoulder is described by 9 points." + ], + "bbox": [ + 511, + 412, + 890, + 590 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Note that $P^M, P^E$ , and $P^F$ are in canonical space for the convenience of face alignment. The process of talking portrait can be rewritten as $\\mathbf{A} \\rightarrow \\mathbf{R} \\rightarrow \\mathbf{V}$ . We design corresponding networks for these stages, respectively. The details are provided in the following subsections.", + "bbox": [ + 496, + 593, + 890, + 670 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Mapping-Once Network with Dual Attentions", + "text_level": 1, + "bbox": [ + 498, + 680, + 885, + 696 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Mapping-once architecture. Given the driven audio A and subject condition S, MODA aims to map them into R (consists of lip movement, eye blinking, head pose, and torso) with a single forward process. As illustrated in Fig. 3, the network in the first step contains three parts, i.e., 1) two encoders for encoding audio features and extracting subject style, respectively, 2) a dual-attention module for generating diverse but accurate motion features, and 3) four tails for different motion synthesis. We first extract contextual features of the audio signal by Wav2Vec [30]. In the next, the extracted feature is projected into $s_a \\in \\mathbb{R}^{d \\times T}$ via a multilayer perceptron (MLP), where $d$ is the feature dimension for one frame and $T$ denotes the number of frames of the", + "bbox": [ + 496, + 704, + 890, + 898 + ], + "page_idx": 2 + }, + { + "type": "footer", + "text": "23022", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/6e31bd9ac8c9ffa51adb6cba4928567840ea8f60b69124b2059dcbb9e3f596ee.jpg", + "image_caption": [ + "Figure 3: Architecture of MODA network. Given an audio and subject condition, MODA generates four types of motions within a single forward process. $\\oplus$ denotes element-wise addition and $\\odot$ is concatenation." + ], + "image_footnote": [], + "bbox": [ + 83, + 87, + 890, + 281 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "generated video. To model different speaker styles, we take the facial vertices of the conditioned subject as input. Then those vertices are projected to a $d$ -dimensional vector $v_{s}$ as the subject style code. Here the embedding layer is implemented by MLP. Next, $s_a$ and $v_{s}$ are combined as:", + "bbox": [ + 75, + 334, + 470, + 411 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\ns = s _ {a} \\oplus \\operatorname {t i l e} \\left(v _ {s}\\right), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 210, + 426, + 468, + 444 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $s$ is the combined feature, $\\oplus$ is dimension-wise addition. Then the dual-attention module (DualAttn) takes $s$ , $s_a$ as input, and yields a temporally contextual version $s_t$ ,", + "bbox": [ + 76, + 450, + 468, + 497 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\ns _ {t} = \\operatorname {D u a l A t t n} (s, s _ {a}). \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 197, + 511, + 468, + 527 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Next, we adopt 4 MLPs to decode the movements of lips $P^{M}$ , head pose $H$ , eye blinking $P^{E}$ , and torso $P^{S}$ , respectively. For each downstream task $X$ , the computational process can be formulated as follows,", + "bbox": [ + 76, + 539, + 468, + 599 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\Delta X = \\Phi^ {X} \\left(s _ {t}\\right), \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 217, + 612, + 468, + 630 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\Phi (\\cdot)$ denotes an MLP and $\\Delta X = X - \\overline{X}$ , $\\overline{X}$ is extracted from referred subject image.", + "bbox": [ + 75, + 641, + 468, + 672 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Dual-attention module. The talking portrait generation task is highly ill-posed since it requires generating multimodal results from limited-driven information. To solve this, we propose a dual-attention module that disentangles this task into a specific mapping and a probabilistic mapping problem. Specifically, this module generates 1) the temporally aligned feature for specific mapping between audio and lip movements, as well as 2) the temporally correlated feature for probabilistic mapping between audio and other movements of the talking portrait. To this end, we first design two sub-modules to learn these two different features, respectively. Then we fuse these two features via time-wise concatenation.", + "bbox": [ + 75, + 672, + 468, + 867 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In detail, we propose a specific attention branch (SpecAttn) to capture the temporally aligned attention", + "bbox": [ + 76, + 869, + 470, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "$s_{sa}$ between $s$ and audio feature $s_a$ . Inspired by FaceFormer [6], our SpecAttn is formulated as:", + "bbox": [ + 498, + 334, + 890, + 364 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} s _ {s a} = \\operatorname {S p e c A t t n} \\left(s _ {a}, s\\right) \\\\ = \\operatorname {s o f t m a x} \\left(\\frac {\\Gamma (s) \\cdot s _ {a} ^ {T}}{\\sqrt {d}} + M _ {A}\\right) \\Gamma (s), \\tag {4} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 566, + 375, + 890, + 429 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $d$ is the dimension of $s_a, \\{\\cdot\\}^T$ indicates the transpose of the input parameter. The alignment bias $M_A(1 \\leq i \\leq T, 1 \\leq j \\leq T)$ is represented as:", + "bbox": [ + 498, + 438, + 890, + 484 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nM _ {A} (i, j) = \\left\\{ \\begin{array}{l l} 0, & i = j \\\\ - \\infty , & \\text {o t h e r w i s e .} \\end{array} \\right. \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 576, + 494, + 890, + 529 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Different from FaceFormer which performs cross-attention in an auto-regressive manner, we apply this operation on the entire sequence, which boosts the computation speed $T \\times$ faster. In addition, to capture rich temporal information, we adopt a periodic positional encoding (PPE) and a biased casual self-attention on $s$ (as in [6]):", + "bbox": [ + 498, + 537, + 890, + 628 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\ns ^ {\\prime} = \\Gamma (s) = \\operatorname {s o f t m a x} \\left(\\frac {\\mathrm {P P E} (s) \\cdot \\mathrm {P P E} (s) ^ {T}}{\\sqrt {d}} + M _ {T}\\right) \\mathrm {P P E} (s). \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 504, + 636, + 890, + 683 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "$M_T$ is a matrix that has negative infinity in the upper triangle to avoid looking at future frames to make current predictions. $M_T$ is defined as:", + "bbox": [ + 498, + 683, + 890, + 729 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nM _ {T} (i, j) = \\left\\{ \\begin{array}{l l} \\lfloor (i - j) q \\rfloor , & j \\leq i, \\\\ - \\infty , & \\text {o t h e r w i s e}, \\end{array} \\right. \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 558, + 737, + 890, + 771 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $q$ is a hyper-parameter for tuning the sequence period. By doing this, the encoded feature $s'$ contains rich spatial-temporal information, which aids the accurate talking portrait generation.", + "bbox": [ + 496, + 780, + 890, + 840 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To generate vivid results and avoid the oversmoothing [44] representations, it is essential to learn the probabilistic mapping between the audio feature and portrait motions. We notice that Variational Autoencoder", + "bbox": [ + 496, + 840, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "footer", + "text": "23023", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "(VAE) [17] can model probabilistic synthesis and shows many advanced performances in sequence generation tasks. Therefore, based on an advanced transformer Variational Autoencoder (t-VAE) [28], we design a probabilistic attention branch to generate diverse results. Formally, given the representation $s$ , the probabilistic attention (ProbAttn) aims to generate a diverse feature $s_{pa}$ . It first models the distribution of $s$ with learned $\\mu$ and $\\sigma$ through an encoder (Enc). Then it generates multimodal outputs through a re-sample operation with a decoder (Dec). The computational process is", + "bbox": [ + 75, + 90, + 472, + 257 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mu , \\log \\sigma = \\Phi^ {\\mu} (\\operatorname {E n c} (s)), \\Phi^ {\\sigma} (\\operatorname {E n c} (s)), \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 140, + 267, + 468, + 291 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\ns _ {p a} = \\operatorname {D e c} (x), \\text {s . t .} x \\sim \\mathcal {U} (\\mu , \\sigma),\n$$\n", + "text_format": "latex", + "bbox": [ + 173, + 287, + 401, + 303 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\Phi$ is an MLP. $\\mathcal{U}(\\mu, \\sigma)$ is the Gaussian distribution with mean $\\mu$ and variance $\\sigma$ . To force ProbAttn to learn diverse motion styles, we add Kullback-Leibler divergence (KLD) loss to constrain the feature from the bottleneck of t-VAE. The KLD loss is defined as follows:", + "bbox": [ + 76, + 313, + 470, + 388 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {K L D} = \\left(- \\frac {1}{2 d _ {l}} \\sum^ {d _ {l}} (\\log \\sigma - \\mu^ {2} - \\sigma + 1), \\right. \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 129, + 397, + 468, + 433 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $d_{l}$ is the dimension of $\\mu$ . Finally, the dual-attention module outputs $s_{t} = s_{sa} \\odot s_{pa}$ for downstream tasks.", + "bbox": [ + 76, + 441, + 468, + 472 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Loss functions. The MODA has four decoders for generating talking portrait-related motions. To learn the mapping from the dual-attention module and four different types of motion, we adopt a multi-task learning scheme for MODA. Specifically, we minimize the $L_{1}$ distance between the ground-truth displacements and the predicted displacements. The loss can be written as", + "bbox": [ + 76, + 472, + 468, + 575 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {L} _ {T P} = \\lambda_ {1} \\left| \\Delta P _ {g t} ^ {M} - \\Delta P ^ {M} \\right| + \\lambda_ {2} \\left| \\Delta R _ {g t} - \\Delta R \\right| \\tag {10} \\\\ + \\lambda_ {3} | \\Delta P _ {g t} ^ {E} - \\Delta P ^ {E} | + \\lambda_ {4} | \\Delta P _ {g t} ^ {S} - \\Delta P ^ {S} |, \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 99, + 584, + 468, + 625 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\lambda_1, \\lambda_2, \\lambda_3, \\lambda_4$ are hyper-parameters for balancing the different weights of downstream tasks. $|\\cdot|$ is the $L_{1}$ -norm. $\\Delta P_{gt}^{*}$ and $\\Delta P^{*}$ indicate the displacements of the ground truth and the predicted result, respectively. The total loss function is the sum of $\\mathcal{L}_{TP}$ and $\\mathcal{L}_{KLD}$ , i.e.,", + "bbox": [ + 76, + 633, + 468, + 709 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {T P} + \\mathcal {L} _ {K L D}. \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 189, + 720, + 468, + 736 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.3. FacialComposerNetwork", + "text_level": 1, + "bbox": [ + 76, + 756, + 313, + 772 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Given the subject information $\\mathbf{S}$ , the generated mouth points $P^{M}$ , and eye points $P^{E}$ , the facial composer network (FaCo-Net) aims to compose the refined facial dense landmarks. The generated facial dense landmarks $P^{F} = \\mathrm{FaCo - Net}(\\mathbf{S}, P^{M}, P^{E})$ . FaCo-Net consists of three encoders for consuming those three inputs and a decoder for facial landmarks generation. Similar to MODA, the subject encoder projects facial points $\\mathbf{S}$ into a style code $\\pmb{p}_{f}$ . The", + "bbox": [ + 76, + 780, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "$P^{M}$ and $P^{E}$ are also projected to $\\pmb{p}_{m}$ and $\\pmb{p}_{e}$ , which share the same latent space as $\\pmb{p}_{f}$ . Next, $P^{F} = \\Psi_{c}((\\pmb{p}_{m} \\odot \\pmb{p}_{e}) \\oplus \\pmb{p}_{f})$ , where $\\Psi_{c}$ is a facial dense point decoder. We adopt a vanilla GAN architecture [8] as the backbone of the discriminator $(D)$ . The FaCo-Net is trained to generate \"realistic\" facial dense points to fool $D$ , whereas $D$ is trained to distinguish the generated facial points from ground truths. The detailed architectures can be found in the supplementary materials. We use LSGAN loss [20] as the adversarial loss to optimize the D:", + "bbox": [ + 498, + 90, + 890, + 242 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {D i s c}} (D) = (z - 1) ^ {2} + \\hat {z} ^ {2}, \\tag {12}\n$$\n", + "text_format": "latex", + "bbox": [ + 599, + 250, + 890, + 267 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $z, \\hat{z}$ is the discriminator output when inputting the ground-truth face points $P_{gt}^{F}$ and the generated $P^{F}$ , respectively. The loss for the generator is", + "bbox": [ + 498, + 276, + 890, + 321 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {G} = \\mathcal {L} _ {G A N} (\\text {F a C o - N e t}) + \\lambda \\left| P _ {g t} ^ {F} - P ^ {F} \\right|, \\tag {13}\n$$\n", + "text_format": "latex", + "bbox": [ + 555, + 329, + 890, + 348 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $P_{gt}^{F}$ is the ground-truth dense face landmarks. $\\mathcal{L}_{GAN}(\\mathrm{FaCo - Net}) = (\\hat{z} -1)^2$ is the adversarial loss, where $\\hat{z} = D(P^F)$ . The weight $\\lambda$ is empirically set to 10. After composition, the facial landmarks $P^{F}$ are transformed to the camera coordinate via head pose $H$ . The transformed facial landmarks and torso points $P^T$ are projected into image space for photorealistic rendering.", + "bbox": [ + 498, + 356, + 890, + 463 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.4. Portrait Image Synthesis with TPE", + "text_level": 1, + "bbox": [ + 500, + 470, + 803, + 486 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The last stage of our system is a renderer that generates photorealistic facial renderings from previous predictions, as illustrated in Fig. 2. Specifically, we design a U-Net-like renderer $G_{R}$ with TPE to generate both high-fidelity and stable videos. In our experiments, TPE is defined as", + "bbox": [ + 498, + 494, + 890, + 569 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {T P E} _ {(t, 2 i)} = \\sin \\left(t * 2 ^ {i} / 1 0 0\\right), \\tag {14}\n$$\n", + "text_format": "latex", + "bbox": [ + 607, + 578, + 890, + 603 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {T P E} _ {(t, 2 i + 1)} = \\cos (t * 2 ^ {i} / 1 0 0).\n$$\n", + "text_format": "latex", + "bbox": [ + 591, + 599, + 799, + 616 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "$i = 0,1,\\ldots ,5$ is the dimension and $t$ is the frame index. Then the rendered result $t$ -frame $I_{t}$ is generated with $G_{R}$ ..", + "bbox": [ + 500, + 623, + 888, + 654 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nI _ {t} = G _ {R} \\left(I _ {t} ^ {c} \\odot I _ {r} \\odot \\mathrm {T P E} (t)\\right), \\tag {15}\n$$\n", + "text_format": "latex", + "bbox": [ + 596, + 662, + 890, + 679 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $I_{t}^{c}$ is the condition image at frame index $t$ . $I_{r}$ is the reference image. The detailed architecture, training, and inference details are provided in our supplementary materials.", + "bbox": [ + 498, + 686, + 890, + 734 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.5. Implementation Details", + "text_level": 1, + "bbox": [ + 500, + 741, + 715, + 757 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Our models are trained on PyTorch [27] using Adam optimizer with hyper-parameters $(\\beta_{1},\\beta_{2}) = (0.9,0.99)$ . The learning rate is set to $10^{-4}$ in all experiments.", + "bbox": [ + 498, + 763, + 890, + 809 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We train all of our models on an NVIDIA 3090 GPU. It takes about (30, 2, 6) hours in total, (200, 300, 100) epochs with bath sizes of (32, 32, 4) for our three different stages, respectively. During testing, we select all the models with minimum validation loss. We use a sliding window (window size 300, stride 150) for arbitrary long input audio.", + "bbox": [ + 498, + 810, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "23024", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/6f77d569b3f569f92187ec2819b96a55e6e5f6516f890ec85c8c3bbd5c3d40d8.jpg", + "table_caption": [ + "Table 1: Comparisons with state-of-the-art methods. † denotes our generated results with size $256 \\times 256$ through a small renderer. The best results are highlighted in **bold**. The number with **underline** denotes the second-best result." + ], + "table_footnote": [], + "table_body": "
MethodTestset A from LSP [22]Testset B from HDTF [51]
NIQE ↓LMD-v ↓LMD ↓Sync ↑MA ↑NIQE ↓LMD-v ↓LMD ↓Sync ↑MA ↑
MakeItTalk (SIGGRAPH Asia'20 [54])7.072.302.653.070.488.181.912.233.900.53
Wav2Lip (MM'20 [29])7.311.951.815.580.647.832.081.975.780.51
Wav2Lip-GAN (MM'20 [29])7.242.111.835.470.627.772.011.985.780.51
LSP (SIGGRAPH Asia'21 [22])5.752.282.063.090.617.121.672.014.110.52
AD-NeRF (ICCV'21 [10])5.812.892.772.980.41-----
SadTalker (CVPR'23 [50])5.802.512.314.140.567.072.432.373.960.51
GeneFace (ICLR'23 [44])6.612.222.173.080.65-----
Ground Truth (reference)5.280.000.004.891.006.380.000.006.071.00
Ours †5.771.741.514.520.707.051.602.044.340.59
Ours5.551.791.504.480.696.921.591.964.160.56
", + "bbox": [ + 78, + 130, + 893, + 327 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 333, + 209, + 349 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Experimental Setup", + "text_level": 1, + "bbox": [ + 76, + 358, + 267, + 375 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Dataset pre-processing. We evaluate our method on two publicly available datasets, i.e., HDTF [51] and Video samples from LSP [22] (LSP dataset). Each video contains a high-resolution portrait with an audio track. The average video length is 1-5 minutes and we process them at 25 fps. We randomly select $80\\%$ of them for training and the remaining videos for evaluation. Specifically, we get 132 videos for training and 32 videos for evaluation. Each video is cropped to keep the face at the center and then resized to $512 \\times 512$ . The LSP dataset contains 5 different target sequences of 4 different subjects for training and testing. These sequences span a range of 3-5 minutes. All videos are extracted at 25 fps and the synchronized audio is sampled at $16K\\mathrm{Hz}$ frequency. We split videos as $80\\% / 20\\%$ for training and validation.", + "bbox": [ + 75, + 382, + 468, + 608 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We detect 478 3D facial landmarks for all videos using Mediapipe*. Then we estimate the head pose $H$ for all videos using method [9]. According to these head poses, the 3D facial landmarks are projected to the canonical space through rigid transformation. We extract the 3D mouth points, and eye-related points as $P^M$ and $P^E$ for each frame. The torso points are estimated from the boundary of the shoulders, which is detected through the face parsing algorithm†. For more data pre-processing details please refer to our supplement materials.", + "bbox": [ + 75, + 609, + 468, + 760 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Evaluation metrics. We demonstrate the superiority of our method on multiple metrics that are widely involved in the talking portrait field. To evaluate the correctness of generated mouth, we use mouth landmark distance (LMD) and velocity of mouth landmark distance (LMD- $\\upsilon$ ) between generated video and reference video in canonical space. In", + "bbox": [ + 75, + 761, + 470, + 852 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/0271c542186ab66eee211f430b89c1a4bb6a0836b6b82ea9bf4ee33bcae07aaa.jpg", + "image_caption": [ + "Figure 4: Visual comparison of 5 methods." + ], + "image_footnote": [], + "bbox": [ + 503, + 329, + 890, + 720 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "addition, we also calculate the Insertion-over-Union (IoU) for the overlap between the predicted mouth area and the ground truth area (MA). We use the confidence score from SyncNet (Sync) [29] to measure the audio-video synchronization. Since the result cannot be perfectly aligned with the ground-truth video, we use Natural Image Quality Evaluator (NIQE) [24] as the metric for image quality. NIQE is able to capture the naturalness of image details, it is widely used in blind image quality assessment.", + "bbox": [ + 496, + 763, + 890, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_footnote", + "text": "\\*https://google.github.io/mediapipe/ $\\dagger$ https://github.com/zllrunning/face-parsing. PyTorch", + "bbox": [ + 76, + 862, + 441, + 900 + ], + "page_idx": 5 + }, + { + "type": "footer", + "text": "23025", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/e2e78a4c0748ce01e56e335989a797f5e47305cbe8bb8499b2f6b5616eba8cc3.jpg", + "image_caption": [ + "Figure 5: Multimodal results with the same mouth shape." + ], + "image_footnote": [], + "bbox": [ + 81, + 89, + 467, + 247 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.2. Quantitative Comparison", + "text_level": 1, + "bbox": [ + 76, + 284, + 308, + 300 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We compare our method with several state-of-the-art one-shot talking portrait generation works (LSP [22], MakeItTalk [54], Wav2Lip [29], AD-NeRF [10], SadTalker [50], and GeneFace [44]). For MakeItTalk, Wav2Lip, and SadTalker, the evaluation is performed on their publicly available checkpoint directly. Since these methods only generate low-resolution results, we retrained a small portrait renderer to generate low-resolution results for a fair comparison. The rest methods are retrained on our dataset under the same condition. Note that AD-NeRF and GeneFace are NeRF-based methods that are extremely time-consuming on all videos, we only provide the numerical results on the LSP dataset. As shown in Tab. 1, the proposed method achieves the best overall video quality (lowest NIQE, 5.25) and the correctness of audio-lip synchronization (lowest LMD, LMD- $v$ , and highest MA). Our method also shows comparable performance with other fully talking-head generation methods in terms of lip-sync score. Please note that a higher sync score is not always lead to better results since it is too sensitive to the audio where unnatural lip movements may get a better score [50].", + "bbox": [ + 75, + 308, + 472, + 625 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Qualitative Evaluation", + "text_level": 1, + "bbox": [ + 76, + 635, + 287, + 648 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "User Study. We conduct user studies with 20 attendees on 30 videos generated by ours and the other methods. The driving audio is selected from four different languages: English, Chinese, Japanese, and German. The videos are generated across 5 subjects. Each participant is asked to select the best generated talking-portrait videos based on three major aspects: lip synchronization accuracy, the naturalness of movements including head movement, eye blinking, and upper body movement, and the video quality of the generated portrait. We collect the voting results and calculate the best-voting percentage of each method. The statistics are reported in Tab. 2. Overall, users prefer our results on lip synchronization, the naturalness of portrait, and video quality, indicating the effectiveness of the proposed method.", + "bbox": [ + 75, + 657, + 468, + 869 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Qualitative comparison. Fig. 4 demonstrates the visual comparison among different methods. The results from", + "bbox": [ + 76, + 869, + 468, + 900 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "LSP [22] have some warping effects without 3D consistency. Wav2Lip [29] can generate accurate mouth motions. However, their mouth areas usually have blurry boundaries and artifacts, which make the video unnatural. The results from AD-NeRF [10] have blurry boundaries of shoulders. SadTalker [50] may suffer from out of sync. GeneFace [44] has obvious artifacts on the neck region. Compared to these methods, our system generates portrait videos with overall high-quality and natural mouth movements.", + "bbox": [ + 496, + 90, + 890, + 226 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Diverse outputs. Fig. 5 shows the diverse rendered videos that are driven by the same audio. These videos have different head poses, eye-blinking, and upper bodies while sharing the same mouth structures. These results demonstrate that our MODA network is able to generate vivid and diverse talking portrait videos.", + "bbox": [ + 496, + 227, + 890, + 316 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4. Ablation Study and Performance Analysis", + "text_level": 1, + "bbox": [ + 498, + 328, + 857, + 343 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We conduct ablation studies on dual-attention in MODA, FaCo-Net, and TPE in portrait renderer.", + "bbox": [ + 496, + 351, + 890, + 380 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Dual-attention module. We choose to 1) replace DualAttn with a multi-layer LSTM block [12]; 2) remove the specific attention branch and 3) remove the multimodal attention branch to evaluate the effectiveness of the dual-attention module. Numerical results on LSP test set are reported in Tab. 3. Using LSTM block cannot generate multimodal results and the diverse score (here we use the variance of the generated facial landmarks) drops to 0. When removing the specific attention branch from the dual attention block, the MODA generates the over-smoothed lip movement, which may be out of lip synchronization and has large LMD and LMD- $v$ errors.", + "bbox": [ + 496, + 381, + 892, + 561 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "FaCo-Net. The FaCo-Net aims to generate natural and consistent representations for our portrait renderer. We carry out an ablation study on it by removing this stage and directly replacing the eye landmarks and mouth landmarks with facial dense landmarks. Fig. 6a shows that condition images without FaCo-Net contain incorrect connections in the lip area and lose face details, leading to low SSIM $(0.871\\rightarrow 0.843)$ , PSNR $(24.77\\rightarrow 21.96)$ and NIQE $(5.55\\rightarrow 6.71)$ rendered images (as in Tab. 4). These results consistently prove the effectiveness of FaCo-Net.", + "bbox": [ + 496, + 563, + 890, + 712 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Temporally positional encoding. We adopt the temporal consistency metric to measure to evaluate the frame-wise consistency (TCM [37]) of the generated videos. Specifically, the TCM is defined as", + "bbox": [ + 496, + 713, + 890, + 773 + ], + "page_idx": 6 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {T C M} = \\frac {1}{T} \\sum_ {t} ^ {T} \\exp \\left(- \\frac {\\left| \\left| O _ {t} - \\operatorname {w a r p} \\left(O _ {t - 1}\\right) \\right| \\right| ^ {2}}{\\left| \\left| V _ {t} - \\operatorname {w a r p} \\left(V _ {t - 1}\\right) \\right| \\right| ^ {2}} - 1\\right), \\tag {16}\n$$\n", + "text_format": "latex", + "bbox": [ + 509, + 785, + 890, + 825 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "where $O_{t}$ and $V_{t}$ represent the $t^{th}$ frame in the referenced video (O) and generated video (V), respectively. $\\operatorname{warp}(\\cdot)$ is the warping function using the optical flow [13]. The 2-norm of a matrix $||\\cdot||$ is the sum of squares of its elements.", + "bbox": [ + 496, + 839, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "23026", + "bbox": [ + 478, + 924, + 517, + 935 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/6ded44c506e3aaafaa7fc8a882b1d9bc35a909e850ec888659e954524b90d374.jpg", + "table_caption": [ + "Table 2: User study analyses measured by best-voting percentage. Higher is better." + ], + "table_footnote": [], + "table_body": "
ApproachLow resolution (256 × 256)High resolution (512 × 512)
MakeItTalk [54]Wav2lip [29]SadTalker [50]OursLSP [22]AD-NeRF [10]GeneFace [44]Ours
Lip-sync accuracy15.2%30.5%16.5%37.6%24.6%7.9%19.0%48.5%
Naturalness of movement12.8%14.0%18.6%54.5%19.0%6.3%7.1%67.6%
Image quality8.3%7.2%14.3%70.0%22.8%11.1%16.7%49.7%
", + "bbox": [ + 84, + 116, + 885, + 208 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/aa523b32c9e3912c9914acebe57e5786d853fd699327d1bb6f072788a5820c1c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 83, + 220, + 328, + 303 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/06675cee64f954c3b161bea895b7882631ff84568a81d7a916a1632c53aa4360.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 359, + 220, + 890, + 304 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/4a0fea6cb7e91ce5822cbe57d051c7fb431e2f35893e752bf42ff37f1e565f23.jpg", + "image_caption": [ + "(a) Effectiveness of FaCo-Net." + ], + "image_footnote": [], + "bbox": [ + 81, + 305, + 326, + 385 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/e211b0474c29e01bdabbfdecb17f55409b9187ecc8087cfa493c7f235c312608.jpg", + "image_caption": [ + "(b) Effectiveness of TPE.", + "Figure 6: Ablation studies on FaCo-Net (a) and temporal positional encoding (b)." + ], + "image_footnote": [], + "bbox": [ + 359, + 305, + 890, + 388 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/92af53edc81f0253bc2258cf521564530b3cd8de37daec099b9a2811562380f8.jpg", + "table_caption": [ + "Table 3: Ablation study on MODA. Removing dual attention or replacing it with LSTM block has negative effects." + ], + "table_footnote": [], + "table_body": "
MethodLMD-vLMDDiverse
replace with LSTM2.492.790
w/o multimodal attention3.012.810
w/o specific attention1.801.551.70
Final1.791.501.57
", + "bbox": [ + 81, + 491, + 465, + 583 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/aec330b08c7b23e9fc7c0c5557563ade415ee331afd06bde659a47f4d0487191.jpg", + "table_caption": [ + "Table 4: Ablation study on FaCo-Net." + ], + "table_footnote": [], + "table_body": "
MethodSSIM ↑PSNR ↑NIQE ↓
w/o FaCo-Net Net0.84321.966.71
Final0.87124.775.55
", + "bbox": [ + 93, + 625, + 454, + 685 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/0fc33675f1966d649a3a4fd72c050446dcf35cb410321174bb488a5e96ed8e46.jpg", + "table_caption": [ + "Table 5: Ablation study on TPE. Higher is better." + ], + "table_footnote": [], + "table_body": "
MethodTCM ↑
Renderer w/o TPE0.63
Renderer with TPE0.71
", + "bbox": [ + 112, + 724, + 429, + 785 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Through this equation, the generated video (V) is encouraged to be temporally consistent according to variations in the reference video (O). Fig. 6b demonstrates the comparison of video sequences with/without TPE. We find TPE can stabilize video synthesis, especially when training videos with changing backgrounds. Numerical results in Tab. 5 also show that TPE can increase TCM score.", + "bbox": [ + 75, + 794, + 468, + 898 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Discussions and Conclusions", + "text_level": 1, + "bbox": [ + 500, + 460, + 763, + 476 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We present a deep learning approach for synthesizing multimodal photorealistic talking-portrait animation from audio streams. Our method can render multiple personalized talking styles with arbitrary audio. Our system contains three stages, i.e., MODA, FaCo-Net, and a high-fidelity portrait renderer with temporal guidance. The first stage generates lip motion, head motion, eye blinking, and torso motion with a unified network. This network adopts a dual-attention mechanism and is able to generate diverse talking-portrait representations with correct lip synchronization. The second stage generates fine-grained facial dense landmarks powered by generated lip motion and eye blinking. Finally, we generate the intermediate representations for our temporal-guided renderer to synthesize both high-fidelity and stable talk-portrait videos. Experimental results and user studies show the superiority of our method. Analytical experiments have also verified different parts of our system.", + "bbox": [ + 496, + 496, + 890, + 755 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Limitations and future work. While our approach achieves impressive results in a wide variety of scenarios, there still exist several limitations. Similar to most deep learning-based methods, our method cannot generalize well on unseen subjects or extremely out-of-domain audio. It may require fine-tuning the renderer for new avatars. We also looking forward to future work to find a person-invariant renderer to achieve high-quality synthesis without additional finetuning.", + "bbox": [ + 496, + 763, + 892, + 901 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "23027", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 174, + 106 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Iz Beltagy, Matthew E Peters, and Arman Cohan. Longformer: The long-document transformer. arXiv preprint arXiv:2004.05150, 2020. 3", + "[2] Lele Chen, Guofeng Cui, Celong Liu, Zhong Li, Ziyi Kou, Yi Xu, and Chenliang Xu. Talking-head generation with rhythmic head motion. In ECCV, 2020. 1", + "[3] Lele Chen, Ross K. Maddox, Zhiyao Duan, and Chenliang Xu. Hierarchical cross-modal talking face generation with dynamic pixel-wise loss. In CVPR, 2019. 1", + "[4] Joon Son Chung, Andrew Senior, Oriol Vinyals, and Andrew Zisserman. Lip reading sentences in the wild. In CVPR, 2017. 1, 2", + "[5] Pif Edwards, Chris Landreth, Eugene Fume, and Karan Singh. Jali: an animator-centric viseme model for expressive lip synchronization. TOG, 35(4):1-11, 2016. 2", + "[6] Yingruo Fan, Zhaojiang Lin, Jun Saito, Wenping Wang, and Taku Komura. Faceformer: Speech-driven 3d facial animation with transformers. In CVPR, 2022. 1, 2, 4", + "[7] Guy Gafni, Justus Thies, Michael Zollhofer, and Matthias Nießner. Dynamic neural radiance fields for monocular 4d facial avatar reconstruction. In CVPR, 2021. 1", + "[8] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In NeurIPS, 2014. 1, 5", + "[9] Jianzhu Guo, Xiangyu Zhu, Yang Yang, Fan Yang, Zhen Lei, and Stan Z Li. Towards fast, accurate and stable 3d dense face alignment. In ECCV, 2020. 6", + "[10] Yudong Guo, Keyu Chen, Sen Liang, Yong-Jin Liu, Hujun Bao, and Juyong Zhang. Ad-nerf: Audio driven neural radiance fields for talking head synthesis. In ICCV, 2021. 2, 6, 7, 8, 12, 14", + "[11] Kai Han, Yunhe Wang, Hanting Chen, Xinghao Chen, Jianyuan Guo, Zhenhua Liu, Yehui Tang, An Xiao, Chunjing Xu, Yixing Xu, et al. A survey on vision transformer. PAMI, 45(1):87-110, 2022. 3", + "[12] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 9(8):1735-1780, 1997. 7", + "[13] Berthold KP Horn and Brian G Schunck. Determining optical flow. Artificial intelligence, 17(1-3):185–203, 1981. 7", + "[14] Xinya Ji, Hang Zhou, Kaisiyuan Wang, Qianyi Wu, Wayne Wu, Feng Xu, and Xun Cao. Eamm: One-shot emotional talking face via audio-based emotion-aware motion model. In SIGGRAPH, 2022. 2", + "[15] Tero Karras, Timo Aila, Samuli Laine, Antti Herva, and Jaakko Lehtinen. Audio-driven facial animation by joint end-to-end learning of pose and emotion. TOG, 36(4):1-12, 2017. 2", + "[16] Salman Khan, Muzammal Naseer, Munawar Hayat, Syed Waqas Zamir, Fahad Shahbaz Khan, and Mubarak Shah. Transformers in vision: A survey. arXiv preprint arXiv:2101.01169, 2021. 2", + "[17] D. P. Kingma and M. Welling. Auto-encoding variational bayes. In ICLR, 2014. 5" + ], + "bbox": [ + 78, + 116, + 468, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[18] Prajwal KR, Rudrabha Mukhopadhyay, Jerin Philip, Abhishek Jha, Vinay Namboodiri, and CV Jawahar. Towards automatic face-to-face translation. In ACMMM, 2019. 1", + "[19] Avisek Lahiri, Vivek Kwatra, Christian Frueh, John Lewis, and Chris Bregler. Lipsync3d: Data-efficient learning of personalized 3d talking faces from video using pose and lighting normalization. In CVPR, 2021. 2", + "[20] Ming-Yu Liu, Thomas Breuel, and Jan Kautz. Unsupervised image-to-image translation networks. In NeurIPS, 2017. 3, 5", + "[21] Xian Liu, Yinghao Xu, Qianyi Wu, Hang Zhou, Wayne Wu, and Bolei Zhou. Semantic-aware implicit neural audio-driven video portrait generation. In ECCV. Springer, 2022. 2", + "[22] Yuanxun Lu, Jinxiang Chai, and Xun Cao. Live speech portraits: real-time photorealistic talking-head animation. TOG, 40(6):1-17, 2021. 1, 2, 3, 6, 7, 8, 11, 12, 14", + "[23] Larry R Medsker and LC Jain. Recurrent neural networks. Design and Applications, 5:64-67, 2001. 3", + "[24] Anish Mittal, Rajiv Soundararajan, and Alan C Bovik. Making a \"completely blind\" image quality analyzer. IEEE Signal processing letters, 20(3):209-212, 2012. 6", + "[25] Se Jin Park, Minsu Kim, Joanna Hong, Jeongsoo Choi, and Yong Man Ro. Synctalkface: Talking face generation with precise lip-syncing via audio-lip memory. In AAAI, 2022. 2", + "[26] Razvan Pascanu, Tomas Mikolov, and Yoshua Bengio. On the difficulty of training recurrent neural networks. In ICML, 2013. 3", + "[27] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, et al. Pytorch: An imperative style, high-performance deep learning library. NeurlPS, 32, 2019. 5", + "[28] Mathis Petrovich, Michael J Black, and Gül Varol. Action-conditioned 3d human motion synthesis with transformer vae. arXiv preprint arXiv:2104.05670, 2021. 5", + "[29] KR Prajwal, Rudrabha Mukhopadhyay, Vinay P Namboodiri, and CV Jawahar. A lip sync expert is all you need for speech to lip generation in the wild. In ACMMM, 2020. 1, 2, 6, 7, 8, 12", + "[30] Steffen Schneider, Alexei Baevski, Ronan Collobert, and Michael Auli. Wav2vec: Unsupervised pre-training for speech recognition. arXiv preprint arXiv:1904.05862, 2019. 3", + "[31] Oliver Schreer, Roman Englert, Peter Eisert, and Ralf Tanger. Real-time vision and speech driven avatars for multimedia applications. TMM, 10(3):352-360, 2008. 2", + "[32] Shuai Shen, Wenliang Zhao, Zibin Meng, Wanhua Li, Zheng Zhu, Jie Zhou, and Jiwen Lu. Difftalk: Crafting diffusion models for generalized talking head synthesis. arXiv preprint arXiv:2301.03786, 2023. 2", + "[33] Aliaksandr Siarohin, Stéphane Lathuilière, Sergey Tulyakov, Elisa Ricci, and Nicu Sebe. First order motion model for image animation. NeurIPS, 32, 2019. 2", + "[34] Michal Stypulkowski, Konstantinos Vougioukas, Sen He, Maciej Zięba, Stavros Petridis, and Maja Pantic. Diffused heads: Diffusion models beat gans on talking-face generation. arXiv preprint arXiv:2301.03396, 2023. 2" + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "23028", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[35] Anni Tang, Tianyu He, Xu Tan, Jun Ling, Runnan Li, Sheng Zhao, Li Song, and Jiang Bian. Memories are one-to-many mapping alleviators in talking face generation. arXiv preprint arXiv:2212.05005, 2022. 2", + "[36] Justus Thies, Mohamed Elgharib, Ayush Tewari, Christian Theobalt, and Matthias Nießner. Neural voice puppetry: Audio-driven facial reenactment. In ECCV, 2020. 2", + "[37] S. Varghese, Y. Bayzidi, A. Bar, N. Kapoor, and T. Fingscheidt. Unsupervised temporal consistency metric for video segmentation in highly-automated driving. In CVPR Workshop, 2020. 7, 11", + "[38] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In NeurIPS, 2017. 2", + "[39] Kaisiyuan Wang, Qianyi Wu, Linsen Song, Zhuoqian Yang, Wayne Wu, Chen Qian, Ran He, Yu Qiao, and Chen Change Loy. Mead: A large-scale audio-visual dataset for emotional talking-face generation. In ECCV, 2020. 2", + "[40] Suzhen Wang, Lincheng Li, Yu Ding, Changjie Fan, and Xin Yu. Audio2head: Audio-driven one-shot talking-head generation with natural head motion. In *IJCAI*, 2021. 2", + "[41] Ting-Chun Wang, Ming-Yu Liu, Jun-Yan Zhu, Guilin Liu, Andrew Tao, Jan Kautz, and Bryan Catanzaro. Video-to-video synthesis. In NeurIPS, 2018. 3", + "[42] Xinsheng Wang, Qicong Xie, Jihua Zhu, Lei Xie, et al. Anyonenet: Synchronized speech and talking head generation for arbitrary person. arXiv preprint arXiv:2108.04325, 2021. 2", + "[43] Shunyu Yao, RuiZhe Zhong, Yichao Yan, Guangtao Zhai, and Xiaokang Yang. Dfa-nerf: Personalized talking head generation via disentangled face attributes neural rendering. arXiv preprint arXiv:2201.00791, 2022. 2", + "[44] Zhenhui Ye, Ziyue Jiang, Yi Ren, Jinglin Liu, JinZheng He, and Zhou Zhao. Geneface: Generalized and high-fidelity audio-driven 3d talking face synthesis. In ICLR, 2023. 1, 2, 4, 6, 7, 8, 14", + "[45] Ran Yi, Zipeng Ye, Juyong Zhang, Hujun Bao, and Yong-Jin Liu. Audio-driven talking face video generation with learning-based personalized head pose. arXiv preprint arXiv:2002.10137, 2020. 2", + "[46] Zili Yi, Hao Zhang, Ping Tan, and Minglun Gong. Dualgan: Unsupervised dual learning for image-to-image translation. In ICCV, 2017. 3", + "[47] Changqian Yu, Changxin Gao, Jingbo Wang, Gang Yu, Chunhua Shen, and Nong Sang. Bisenet v2: Bilateral network with guided aggregation for real-time semantic segmentation. IJCV, 129:3051-3068, 2021. 12", + "[48] Egor Zakharov, Aliaksandra Shysheya, Egor Burkov, and Victor Lempitsky. Few-shot adversarial learning of realistic neural talking head models. In ICCV, 2019. 2", + "[49] Chenxu Zhang, Yifan Zhao, Yifei Huang, Ming Zeng, Saifeng Ni, Madhukar Budagavi, and Xiaohu Guo. Facial: Synthesizing dynamic talking face with implicit attribute learning. In ICCV, 2021. 1", + "[50] Wenxuan Zhang, Xiaodong Cun, Xuan Wang, Yong Zhang, Xi Shen, Yu Guo, Ying Shan, and Fei Wang. Sadtalker: Learning realistic 3d motion coefficients for stylized audio-driven single image talking face animation. In CVPR, 2023. 1, 2, 3, 6, 7, 8" + ], + "bbox": [ + 78, + 90, + 468, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[51] Zhimeng Zhang, Lincheng Li, Yu Ding, and Changjie Fan. Flow-guided one-shot talking face generation with a high-resolution audio-visual dataset. In CVPR, 2021. 2, 6", + "[52] Hang Zhou, Yasheng Sun, Wayne Wu, Chen Change Loy, Xiaogang Wang, and Ziwei Liu. Pose-controllable talking face generation by implicitly modularized audio-visual representation. In CVPR, 2021. 1, 2", + "[53] Yijun Zhou and James Gregson. Whenet: Real-time fine-grained estimation for wide range head pose. arXiv preprint arXiv:2005.10353, 2020. 11", + "[54] Yang Zhou, Xintong Han, Eli Shechtman, Jose Echevarria, Evangelos Kalogerakis, and Dingzeyu Li. Makelttalk: speaker-aware talking-head animation. TOG, 39(6):1-15, 2020. 1, 2, 3, 6, 7, 8, 12", + "[55] Yang Zhou, Zhan Xu, Chris Landreth, Evangelos Kalogerakis, Subhransu Maji, and Karan Singh. Visemenet: Audio-driven animator-centric speech animation. TOG, 37(4):1-10, 2018. 2", + "[56] Hao Zhu, Huaibo Huang, Yi Li, Aihua Zheng, and Ran He. Arbitrary talking face generation via attentional audio-visual coherence learning. In IJCAI, 2020. 2" + ], + "bbox": [ + 501, + 92, + 890, + 388 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "23029", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/cd6d82fe-3030-4ffc-8902-e0f3febe9ace_model.json b/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/cd6d82fe-3030-4ffc-8902-e0f3febe9ace_model.json new file mode 100644 index 0000000000000000000000000000000000000000..caa1ffeee57325b9b9181aaf98d189dcad80d9ff --- /dev/null +++ b/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/cd6d82fe-3030-4ffc-8902-e0f3febe9ace_model.json @@ -0,0 +1,2288 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.087, + 0.131, + 0.884, + 0.155 + ], + "angle": 0, + "content": "MODA: Mapping-Once Audio-driven Portrait Animation with Dual Attentions" + }, + { + "type": "text", + "bbox": [ + 0.182, + 0.179, + 0.787, + 0.234 + ], + "angle": 0, + "content": "Yunfei Liu1 Lijian Lin1 Fei Yu2 Changyin Zhou2 Yu Li1* 1International Digital Economy Academy (IDEA) 2Vstring Inc. https://tinyurl.com/iccv23-modala" + }, + { + "type": "image", + "bbox": [ + 0.099, + 0.274, + 0.875, + 0.495 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.078, + 0.5, + 0.891, + 0.516 + ], + "angle": 0, + "content": "Figure 1: We propose a mapping-once system with dual-attention for multimodal and high-fidelity portrait video animation." + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.528, + 0.314, + 0.544 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.56, + 0.474, + 0.864 + ], + "angle": 0, + "content": "Audio-driven portrait animation aims to synthesize portrait videos that are conditioned by given audio. Animating high-fidelity and multimodal video portraits has a variety of applications. Previous methods have attempted to capture different motion modes and generate high-fidelity portrait videos by training different models or sampling signals from given videos. However, lacking correlation learning between lip-sync and other movements (e.g., head pose/eye blinking) usually leads to unnatural results. In this paper, we propose a unified system for multi-person, diverse, and high-fidelity talking portrait generation. Our method contains three stages, i.e., 1) Mapping-Once network with Dual Attentions (MODA) generates talking representation from given audio. In MODA, we design a dual-attention module to encode accurate mouth movements and diverse modalities. 2) Facial composer network generates dense and detailed face landmarks, and 3) temporal-guided renderer syntheses stable videos. Extensive evaluations demonstrate that the proposed system produces more natural and realistic video portraits compared to previous methods." + }, + { + "type": "title", + "bbox": [ + 0.502, + 0.528, + 0.631, + 0.543 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.554, + 0.892, + 0.749 + ], + "angle": 0, + "content": "Given an input audio, talking portrait animation is to synthesize video frames of a person whose poses and expressions are synchronized with the audio signal [2, 3, 4, 18]. This audio-driven portrait video generation task has gained increasing attention recently and has a wide range of applications in digital avatars, gaming, telepresence, virtual reality (VR), video production etc. Conventional portrait video generation consumes intensive labor and time during setting up the background, make-up, lighting, shooting, and editing. Moreover, a re-shot is always required when there exists new textual content. In contrast, audio-driven talking video generation is more convenient and attractive which only requires a new audio clip to render a new video." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.893, + 0.901 + ], + "angle": 0, + "content": "Previous methods [7, 29, 52] try to learn the correspondence between audio and frames. However, these methods usually ignore the head pose as it is hard to separate head posture from facial movement. Many 3D face reconstruction algorithm-based and GAN-based [8] methods estimate intermediate representations, such as 3D face shapes [6, 50], 2D landmarks [22, 54], or face expression parameters [49], to assist the generation process. However, such sparse representations usually lost facial details, leading to over-smooth [44]. Recently, the neural radiance field" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.222, + 0.9 + ], + "angle": 0, + "content": "*Corresponding author." + }, + { + "type": "footer", + "bbox": [ + 0.479, + 0.925, + 0.52, + 0.937 + ], + "angle": 0, + "content": "23020" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.091, + 0.47, + 0.168 + ], + "angle": 0, + "content": "(NeRF) [10, 44] has been widely applied in talking head generation for high-fidelity results. However, the implicit neural representation is hard to interpret and control. In addition, these methods are usually person-specific and require extra training or adaptation time for different persons." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.172, + 0.473, + 0.399 + ], + "angle": 0, + "content": "Although quite a number of attempts and progresses have been made in recent years, it is still challenging to generate realistic and expressive talking videos. As humans are extremely sensitive to identifying the artifacts in the synthesized portrait videos, it sets a very high standard for this technique to become applicable. We summarize the following key points that affect human perceptions: 1) Correctness. The synthesized talking portrait video should be well synchronized with the driven audio. 2) Visual quality. The synthesized video should have high resolution and contain fine detail components. 3) Diversity. Besides the lip motion needing to be exactly matched to the audio content, the motion of other components like eye blinking and head movement are not deterministic. They should move naturally as a natural human does." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.404, + 0.473, + 0.66 + ], + "angle": 0, + "content": "To achieve these goals, previous approaches either map the mouth landmarks and the head pose separately by learning different sub-networks [22, 50], or only model the mouth movement while the head pose is obtained from the existing video [29, 52]. However, lacking correlation learning between lip-sync and other movements usually leads to unnatural results. In this paper, we propose a mapping-once network with dual attentions (MODA), which is a unified architecture to generate diverse representations for a talking portrait, simplifying the computational steps. In order to combine synchronization and diversity of the talking portrait generation, we carefully design a dual-attention module to learn deterministic mappings (i.e., the accurate mouth movements driven by audio) and probabilistic sampling (i.e., the diverse head pose/eye blinking from time-to-time), respectively. To summarize, our contributions can be listed as follows:" + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.675, + 0.468, + 0.735 + ], + "angle": 0, + "content": "- We propose a talking portrait system that generates multimodal photorealistic portrait videos with accurate lip motion. Comprehensive evaluations demonstrate our system can achieve state-of-the-art performance." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.737, + 0.468, + 0.782 + ], + "angle": 0, + "content": "- We propose a unified mapping-once with dual attention (MODA) network for generating portrait representation from subject conditions and arbitrary audio." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.785, + 0.468, + 0.89 + ], + "angle": 0, + "content": "- We propose 3 technical points for taking portrait generation: 1) A transformer-based dual attention module for generating both specific and diverse representations. 2) A facial composer network to get accurate and detailed facial landmarks. 3) A temporally guided renderer to synthesize videos with both high quality and temporal stabilization." + }, + { + "type": "list", + "bbox": [ + 0.097, + 0.675, + 0.468, + 0.89 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.09, + 0.651, + 0.107 + ], + "angle": 0, + "content": "2. Related Works" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.115, + 0.892, + 0.342 + ], + "angle": 0, + "content": "Audio-driven portrait animation. Talking heads and facial animation are research hot-spots in the computer vision community. Extensive approaches [5, 55] explore audio-driven mouth animation and audio-driven facial animation. We focus on animating a portrait in this work. Many methods [4, 5, 29, 31, 56] aim to find the correspondence between audio and frames. A large number of technologies (such as flow-learning [14, 40, 51], memory bank [25, 35], etc.) are explored for the correctness of talking head generation. However, these methods usually ignore the head pose, torso motion, and eye blinking, which are essential for a natural talking portrait generation. To generate diverse talking heads, recent methods [19, 52] propose to embed other modalities to control emotions or head pose. However, these methods usually require additional inputs." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.342, + 0.893, + 0.659 + ], + "angle": 0, + "content": "Recently, neural radiance field (NeRF) [10] has been widely applied in 3D-related tasks as it can accurately reproduce complex scenes with implicit neural representation. Several works [10, 43, 21, 44] leverage NeRF to represent faces with audio features as conditions. Despite the high-quality results achieved, the motion of generated results is usually unnatural. Besides, the learning and inference processes are time-consuming. More recently, some diffusion-based methods [32, 34] are proposed to generate talking heads. However, their speed is limited by a large number of sampling steps in the diffusion process. Some methods are based on the 3D face reconstruction and GAN [15, 22, 45]. They estimate intermediate representations such as 2D landmarks [39, 48, 54], 3D face shapes [15, 36] or facial expression parameters [42, 50], to assist the generation process. Unfortunately, such sparse representation usually lost facial details. In this paper, we propose to learn dense facial landmarks and upper body points through a unified framework for talking portrait generation. The intermediate representation contains facial details and other movements, which can be interpreted and controlled easily." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.66, + 0.892, + 0.81 + ], + "angle": 0, + "content": "Transformers in audio-driven tasks. Transformer [38] is a strong alternative to both RNN and CNN. Researchers find it works well in multimodal scenarios. We refer readers to the comprehensive survey [16] for further information. Some recent works adopt transformers to generate results from different modalities, such as audio-to-text, language translation, music-to-dance, etc. The most related work is FaceFormer [6], which is a speech-driven 3D facial animation approach. They proposed two types of bias for the transformer to better align audio and 3D face animation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Vision-based facial reenactment. Video-based facial reenactment is another technique related to audio-driven animation [33, 31]. There are many works to reenact faces with different techniques, such as adversarial learning, few-shot learning, or even one-shot facial animation. They usually adopt pre-defined facial landmarks or in an unsupervised" + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.518, + 0.937 + ], + "angle": 0, + "content": "23021" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.09, + 0.087, + 0.895, + 0.213 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.222, + 0.895, + 0.281 + ], + "angle": 0, + "content": "Figure 2: The proposed method is a three-stage system. Given the subject figure and arbitrary audio, the proposed system generates audio-driven video. Here \\(\\mathbb{O}\\) denotes rigid transformation from canonical space to camera coordinate via head pose, \\(\\odot\\) denotes concatenation. \\(\\mathbb{P}\\) is projection from 3D space to image coordinate. FaCo-Net is a facial composer network, which will be introduced in Sec. 3.3." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.291, + 0.473, + 0.488 + ], + "angle": 0, + "content": "scheme. In another aspect, image-to-image translation (I2I) methods [20, 46] have also demonstrated impressive performance in converting images from one domain to another. However, single-frame renderers [20] ignore the temporal relations among video frames, leading to color jitters or unnatural background shakes in the final results. [41] proposes to use RNN [23] to capture the temporal relations among the input conditions, which generates stabilized results. However, these methods have difficulties in training [26]. In this paper, we find an alternative way to embed temporal information into I2I. Simply using temporal positional embedding [11] as an input condition, our method can achieve natural and stabilized results." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.505, + 0.214, + 0.523 + ], + "angle": 0, + "content": "3. Methodology" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.531, + 0.47, + 0.713 + ], + "angle": 0, + "content": "We present a talking portrait system for high-fidelity portrait video generation with accurate lip motion and multimodal motions, including head pose, eye blinking, and torso movements. The overall pipeline of this system is illustrated in Fig. 2. It contains three stages, 1) given the driven audio and conditioned subjects, mapping once talking portrait network with dual attentions (MODA) generates multimodal and correct semantic portrait components, 2) in the next, the facial composer network combines the facial components together and adds details for dense facial vertices, and 3) finally, a portrait renderer with temporally positional embedding (TPE) syntheses high-fidelity and stable videos." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.726, + 0.232, + 0.74 + ], + "angle": 0, + "content": "3.1. Task Definition" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.471, + 0.902 + ], + "angle": 0, + "content": "In this section, we give the definition of the talking portrait task, which is to formulate a sequence-to-sequence translation manner [1] from talking portrait videos. Specifically, given a \\(T\\)-length audio sequence \\(\\mathbf{A} = \\{a_0, a_1, \\dots, a_T\\}\\) with audio sampling rate \\(r\\), a talking portrait method aims to map it into the corresponding video clip \\(\\mathbf{V} = \\{I_0, I_1, \\dots, I_K\\}\\) with \\(f\\) frame-per-second (FPS), where \\(K = \\lfloor fT / r \\rfloor\\). Since the data dimension of \\(\\mathbf{V}\\) is much larger than \\(\\mathbf{A}\\), many researchers propose to generate \\(\\mathbf{V}\\) progressively and introduce many types of intermediate" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.291, + 0.892, + 0.411 + ], + "angle": 0, + "content": "representation \\(\\mathbf{R}\\). To make the generated \\(\\mathbf{V}\\) look natural, the constraint on \\(\\mathbf{R}\\) is critical. In previous audio-driven face animation approaches, \\(\\mathbf{R}\\) typically represents one type of face information, such as facial landmarks [22, 54] or head pose [50]. To better represent a talking portrait, we define \\(\\mathbf{R}\\) as the union of different portrait descriptors, i.e., \\(\\mathbf{R} = \\{P^M, P^E, P^F, H, P^T\\}\\), where the elements of \\(\\mathbf{R}\\) are defined as follows," + }, + { + "type": "text", + "bbox": [ + 0.512, + 0.414, + 0.891, + 0.445 + ], + "angle": 0, + "content": "1. Mouth points \\( P^M \\in \\mathbb{R}^{40 \\times 3} \\). They have 40 points for representing mouth animation." + }, + { + "type": "text", + "bbox": [ + 0.512, + 0.447, + 0.891, + 0.478 + ], + "angle": 0, + "content": "2. Eyes points \\( P^{E} \\in \\mathbb{R}^{60 \\times 3} \\). They consist of eye and eyebrow points, which control eye blinking." + }, + { + "type": "text", + "bbox": [ + 0.512, + 0.48, + 0.891, + 0.51 + ], + "angle": 0, + "content": "3. Facial points \\(P^{F} \\in \\mathbb{R}^{478 \\times 3}\\). They contain dense facial 3D points for recording expression details." + }, + { + "type": "text", + "bbox": [ + 0.512, + 0.513, + 0.891, + 0.559 + ], + "angle": 0, + "content": "4. Head pose \\(H \\in \\mathbb{R}^6\\). It contains head rotations \\((\\theta, \\phi, \\psi)\\) in Euler angle and head transposes \\((x, y, z)\\) in Euclidean space)." + }, + { + "type": "text", + "bbox": [ + 0.512, + 0.56, + 0.891, + 0.592 + ], + "angle": 0, + "content": "5. Torso points \\( P^T \\in \\mathbb{R}^{18 \\times 3} \\). They contain 18 points and each side of the shoulder is described by 9 points." + }, + { + "type": "list", + "bbox": [ + 0.512, + 0.414, + 0.891, + 0.592 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.594, + 0.892, + 0.671 + ], + "angle": 0, + "content": "Note that \\( P^M, P^E \\), and \\( P^F \\) are in canonical space for the convenience of face alignment. The process of talking portrait can be rewritten as \\( \\mathbf{A} \\rightarrow \\mathbf{R} \\rightarrow \\mathbf{V} \\). We design corresponding networks for these stages, respectively. The details are provided in the following subsections." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.681, + 0.887, + 0.698 + ], + "angle": 0, + "content": "3.2. Mapping-Once Network with Dual Attentions" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.892, + 0.9 + ], + "angle": 0, + "content": "Mapping-once architecture. Given the driven audio A and subject condition S, MODA aims to map them into R (consists of lip movement, eye blinking, head pose, and torso) with a single forward process. As illustrated in Fig. 3, the network in the first step contains three parts, i.e., 1) two encoders for encoding audio features and extracting subject style, respectively, 2) a dual-attention module for generating diverse but accurate motion features, and 3) four tails for different motion synthesis. We first extract contextual features of the audio signal by Wav2Vec [30]. In the next, the extracted feature is projected into \\( s_a \\in \\mathbb{R}^{d \\times T} \\) via a multilayer perceptron (MLP), where \\( d \\) is the feature dimension for one frame and \\( T \\) denotes the number of frames of the" + }, + { + "type": "footer", + "bbox": [ + 0.479, + 0.925, + 0.521, + 0.937 + ], + "angle": 0, + "content": "23022" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.088, + 0.891, + 0.282 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.292, + 0.895, + 0.325 + ], + "angle": 0, + "content": "Figure 3: Architecture of MODA network. Given an audio and subject condition, MODA generates four types of motions within a single forward process. \\(\\oplus\\) denotes element-wise addition and \\(\\odot\\) is concatenation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.335, + 0.471, + 0.412 + ], + "angle": 0, + "content": "generated video. To model different speaker styles, we take the facial vertices of the conditioned subject as input. Then those vertices are projected to a \\(d\\)-dimensional vector \\(v_{s}\\) as the subject style code. Here the embedding layer is implemented by MLP. Next, \\(s_a\\) and \\(v_{s}\\) are combined as:" + }, + { + "type": "equation", + "bbox": [ + 0.211, + 0.428, + 0.47, + 0.445 + ], + "angle": 0, + "content": "\\[\ns = s _ {a} \\oplus \\operatorname {t i l e} \\left(v _ {s}\\right), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.452, + 0.47, + 0.498 + ], + "angle": 0, + "content": "where \\(s\\) is the combined feature, \\(\\oplus\\) is dimension-wise addition. Then the dual-attention module (DualAttn) takes \\(s\\), \\(s_a\\) as input, and yields a temporally contextual version \\(s_t\\)," + }, + { + "type": "equation", + "bbox": [ + 0.199, + 0.512, + 0.47, + 0.528 + ], + "angle": 0, + "content": "\\[\ns _ {t} = \\operatorname {D u a l A t t n} (s, s _ {a}). \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.54, + 0.47, + 0.601 + ], + "angle": 0, + "content": "Next, we adopt 4 MLPs to decode the movements of lips \\( P^{M} \\), head pose \\( H \\), eye blinking \\( P^{E} \\), and torso \\( P^{S} \\), respectively. For each downstream task \\( X \\), the computational process can be formulated as follows," + }, + { + "type": "equation", + "bbox": [ + 0.218, + 0.613, + 0.47, + 0.631 + ], + "angle": 0, + "content": "\\[\n\\Delta X = \\Phi^ {X} \\left(s _ {t}\\right), \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.642, + 0.469, + 0.673 + ], + "angle": 0, + "content": "where \\(\\Phi (\\cdot)\\) denotes an MLP and \\(\\Delta X = X - \\overline{X}\\), \\(\\overline{X}\\) is extracted from referred subject image." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.674, + 0.47, + 0.868 + ], + "angle": 0, + "content": "Dual-attention module. The talking portrait generation task is highly ill-posed since it requires generating multimodal results from limited-driven information. To solve this, we propose a dual-attention module that disentangles this task into a specific mapping and a probabilistic mapping problem. Specifically, this module generates 1) the temporally aligned feature for specific mapping between audio and lip movements, as well as 2) the temporally correlated feature for probabilistic mapping between audio and other movements of the talking portrait. To this end, we first design two sub-modules to learn these two different features, respectively. Then we fuse these two features via time-wise concatenation." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.471, + 0.902 + ], + "angle": 0, + "content": "In detail, we propose a specific attention branch (SpecAttn) to capture the temporally aligned attention" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.335, + 0.892, + 0.365 + ], + "angle": 0, + "content": "\\(s_{sa}\\) between \\(s\\) and audio feature \\(s_a\\). Inspired by FaceFormer [6], our SpecAttn is formulated as:" + }, + { + "type": "equation", + "bbox": [ + 0.567, + 0.376, + 0.892, + 0.43 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} s _ {s a} = \\operatorname {S p e c A t t n} \\left(s _ {a}, s\\right) \\\\ = \\operatorname {s o f t m a x} \\left(\\frac {\\Gamma (s) \\cdot s _ {a} ^ {T}}{\\sqrt {d}} + M _ {A}\\right) \\Gamma (s), \\tag {4} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.439, + 0.892, + 0.486 + ], + "angle": 0, + "content": "where \\(d\\) is the dimension of \\(s_a, \\{\\cdot\\}^T\\) indicates the transpose of the input parameter. The alignment bias \\(M_A(1 \\leq i \\leq T, 1 \\leq j \\leq T)\\) is represented as:" + }, + { + "type": "equation", + "bbox": [ + 0.577, + 0.495, + 0.892, + 0.53 + ], + "angle": 0, + "content": "\\[\nM _ {A} (i, j) = \\left\\{ \\begin{array}{l l} 0, & i = j \\\\ - \\infty , & \\text {o t h e r w i s e .} \\end{array} \\right. \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.538, + 0.892, + 0.629 + ], + "angle": 0, + "content": "Different from FaceFormer which performs cross-attention in an auto-regressive manner, we apply this operation on the entire sequence, which boosts the computation speed \\( T \\times \\) faster. In addition, to capture rich temporal information, we adopt a periodic positional encoding (PPE) and a biased casual self-attention on \\( s \\) (as in [6]):" + }, + { + "type": "equation", + "bbox": [ + 0.506, + 0.637, + 0.892, + 0.684 + ], + "angle": 0, + "content": "\\[\ns ^ {\\prime} = \\Gamma (s) = \\operatorname {s o f t m a x} \\left(\\frac {\\mathrm {P P E} (s) \\cdot \\mathrm {P P E} (s) ^ {T}}{\\sqrt {d}} + M _ {T}\\right) \\mathrm {P P E} (s). \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.684, + 0.892, + 0.73 + ], + "angle": 0, + "content": "\\(M_T\\) is a matrix that has negative infinity in the upper triangle to avoid looking at future frames to make current predictions. \\(M_T\\) is defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.559, + 0.738, + 0.892, + 0.772 + ], + "angle": 0, + "content": "\\[\nM _ {T} (i, j) = \\left\\{ \\begin{array}{l l} \\lfloor (i - j) q \\rfloor , & j \\leq i, \\\\ - \\infty , & \\text {o t h e r w i s e}, \\end{array} \\right. \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.781, + 0.892, + 0.841 + ], + "angle": 0, + "content": "where \\( q \\) is a hyper-parameter for tuning the sequence period. By doing this, the encoded feature \\( s' \\) contains rich spatial-temporal information, which aids the accurate talking portrait generation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.841, + 0.892, + 0.902 + ], + "angle": 0, + "content": "To generate vivid results and avoid the oversmoothing [44] representations, it is essential to learn the probabilistic mapping between the audio feature and portrait motions. We notice that Variational Autoencoder" + }, + { + "type": "footer", + "bbox": [ + 0.479, + 0.925, + 0.519, + 0.937 + ], + "angle": 0, + "content": "23023" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.091, + 0.473, + 0.258 + ], + "angle": 0, + "content": "(VAE) [17] can model probabilistic synthesis and shows many advanced performances in sequence generation tasks. Therefore, based on an advanced transformer Variational Autoencoder (t-VAE) [28], we design a probabilistic attention branch to generate diverse results. Formally, given the representation \\( s \\), the probabilistic attention (ProbAttn) aims to generate a diverse feature \\( s_{pa} \\). It first models the distribution of \\( s \\) with learned \\( \\mu \\) and \\( \\sigma \\) through an encoder (Enc). Then it generates multimodal outputs through a re-sample operation with a decoder (Dec). The computational process is" + }, + { + "type": "equation", + "bbox": [ + 0.142, + 0.268, + 0.47, + 0.292 + ], + "angle": 0, + "content": "\\[\n\\mu , \\log \\sigma = \\Phi^ {\\mu} (\\operatorname {E n c} (s)), \\Phi^ {\\sigma} (\\operatorname {E n c} (s)), \\tag {8}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.174, + 0.288, + 0.403, + 0.304 + ], + "angle": 0, + "content": "\\[\ns _ {p a} = \\operatorname {D e c} (x), \\text {s . t .} x \\sim \\mathcal {U} (\\mu , \\sigma),\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.314, + 0.471, + 0.389 + ], + "angle": 0, + "content": "where \\(\\Phi\\) is an MLP. \\(\\mathcal{U}(\\mu, \\sigma)\\) is the Gaussian distribution with mean \\(\\mu\\) and variance \\(\\sigma\\). To force ProbAttn to learn diverse motion styles, we add Kullback-Leibler divergence (KLD) loss to constrain the feature from the bottleneck of t-VAE. The KLD loss is defined as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.13, + 0.398, + 0.47, + 0.434 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {K L D} = \\left(- \\frac {1}{2 d _ {l}} \\sum^ {d _ {l}} (\\log \\sigma - \\mu^ {2} - \\sigma + 1), \\right. \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.443, + 0.469, + 0.473 + ], + "angle": 0, + "content": "where \\(d_{l}\\) is the dimension of \\(\\mu\\). Finally, the dual-attention module outputs \\(s_{t} = s_{sa} \\odot s_{pa}\\) for downstream tasks." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.473, + 0.469, + 0.577 + ], + "angle": 0, + "content": "Loss functions. The MODA has four decoders for generating talking portrait-related motions. To learn the mapping from the dual-attention module and four different types of motion, we adopt a multi-task learning scheme for MODA. Specifically, we minimize the \\( L_{1} \\) distance between the ground-truth displacements and the predicted displacements. The loss can be written as" + }, + { + "type": "equation", + "bbox": [ + 0.1, + 0.585, + 0.47, + 0.626 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {L} _ {T P} = \\lambda_ {1} \\left| \\Delta P _ {g t} ^ {M} - \\Delta P ^ {M} \\right| + \\lambda_ {2} \\left| \\Delta R _ {g t} - \\Delta R \\right| \\tag {10} \\\\ + \\lambda_ {3} | \\Delta P _ {g t} ^ {E} - \\Delta P ^ {E} | + \\lambda_ {4} | \\Delta P _ {g t} ^ {S} - \\Delta P ^ {S} |, \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.635, + 0.469, + 0.71 + ], + "angle": 0, + "content": "where \\(\\lambda_1, \\lambda_2, \\lambda_3, \\lambda_4\\) are hyper-parameters for balancing the different weights of downstream tasks. \\(|\\cdot|\\) is the \\(L_{1}\\)-norm. \\(\\Delta P_{gt}^{*}\\) and \\(\\Delta P^{*}\\) indicate the displacements of the ground truth and the predicted result, respectively. The total loss function is the sum of \\(\\mathcal{L}_{TP}\\) and \\(\\mathcal{L}_{KLD}\\), i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.19, + 0.722, + 0.469, + 0.737 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {T P} + \\mathcal {L} _ {K L D}. \\tag {11}\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.757, + 0.315, + 0.773 + ], + "angle": 0, + "content": "3.3. FacialComposerNetwork" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.781, + 0.469, + 0.901 + ], + "angle": 0, + "content": "Given the subject information \\(\\mathbf{S}\\), the generated mouth points \\(P^{M}\\), and eye points \\(P^{E}\\), the facial composer network (FaCo-Net) aims to compose the refined facial dense landmarks. The generated facial dense landmarks \\(P^{F} = \\mathrm{FaCo - Net}(\\mathbf{S}, P^{M}, P^{E})\\). FaCo-Net consists of three encoders for consuming those three inputs and a decoder for facial landmarks generation. Similar to MODA, the subject encoder projects facial points \\(\\mathbf{S}\\) into a style code \\(\\pmb{p}_{f}\\). The" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.091, + 0.892, + 0.243 + ], + "angle": 0, + "content": "\\(P^{M}\\) and \\(P^{E}\\) are also projected to \\(\\pmb{p}_{m}\\) and \\(\\pmb{p}_{e}\\), which share the same latent space as \\(\\pmb{p}_{f}\\). Next, \\(P^{F} = \\Psi_{c}((\\pmb{p}_{m} \\odot \\pmb{p}_{e}) \\oplus \\pmb{p}_{f})\\), where \\(\\Psi_{c}\\) is a facial dense point decoder. We adopt a vanilla GAN architecture [8] as the backbone of the discriminator \\((D)\\). The FaCo-Net is trained to generate \"realistic\" facial dense points to fool \\(D\\), whereas \\(D\\) is trained to distinguish the generated facial points from ground truths. The detailed architectures can be found in the supplementary materials. We use LSGAN loss [20] as the adversarial loss to optimize the D:" + }, + { + "type": "equation", + "bbox": [ + 0.601, + 0.251, + 0.892, + 0.268 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {D i s c}} (D) = (z - 1) ^ {2} + \\hat {z} ^ {2}, \\tag {12}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.277, + 0.892, + 0.322 + ], + "angle": 0, + "content": "where \\(z, \\hat{z}\\) is the discriminator output when inputting the ground-truth face points \\(P_{gt}^{F}\\) and the generated \\(P^{F}\\), respectively. The loss for the generator is" + }, + { + "type": "equation", + "bbox": [ + 0.557, + 0.33, + 0.892, + 0.349 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {G} = \\mathcal {L} _ {G A N} (\\text {F a C o - N e t}) + \\lambda \\left| P _ {g t} ^ {F} - P ^ {F} \\right|, \\tag {13}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.357, + 0.892, + 0.464 + ], + "angle": 0, + "content": "where \\(P_{gt}^{F}\\) is the ground-truth dense face landmarks. \\(\\mathcal{L}_{GAN}(\\mathrm{FaCo - Net}) = (\\hat{z} -1)^2\\) is the adversarial loss, where \\(\\hat{z} = D(P^F)\\). The weight \\(\\lambda\\) is empirically set to 10. After composition, the facial landmarks \\(P^{F}\\) are transformed to the camera coordinate via head pose \\(H\\). The transformed facial landmarks and torso points \\(P^T\\) are projected into image space for photorealistic rendering." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.472, + 0.805, + 0.487 + ], + "angle": 0, + "content": "3.4. Portrait Image Synthesis with TPE" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.495, + 0.892, + 0.57 + ], + "angle": 0, + "content": "The last stage of our system is a renderer that generates photorealistic facial renderings from previous predictions, as illustrated in Fig. 2. Specifically, we design a U-Net-like renderer \\( G_{R} \\) with TPE to generate both high-fidelity and stable videos. In our experiments, TPE is defined as" + }, + { + "type": "equation", + "bbox": [ + 0.608, + 0.579, + 0.892, + 0.604 + ], + "angle": 0, + "content": "\\[\n\\mathrm {T P E} _ {(t, 2 i)} = \\sin \\left(t * 2 ^ {i} / 1 0 0\\right), \\tag {14}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.593, + 0.601, + 0.8, + 0.617 + ], + "angle": 0, + "content": "\\[\n\\mathrm {T P E} _ {(t, 2 i + 1)} = \\cos (t * 2 ^ {i} / 1 0 0).\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.624, + 0.89, + 0.655 + ], + "angle": 0, + "content": "\\(i = 0,1,\\ldots ,5\\) is the dimension and \\(t\\) is the frame index. Then the rendered result \\(t\\) -frame \\(I_{t}\\) is generated with \\(G_{R}\\) .." + }, + { + "type": "equation", + "bbox": [ + 0.598, + 0.663, + 0.892, + 0.68 + ], + "angle": 0, + "content": "\\[\nI _ {t} = G _ {R} \\left(I _ {t} ^ {c} \\odot I _ {r} \\odot \\mathrm {T P E} (t)\\right), \\tag {15}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.688, + 0.892, + 0.735 + ], + "angle": 0, + "content": "where \\( I_{t}^{c} \\) is the condition image at frame index \\( t \\). \\( I_{r} \\) is the reference image. The detailed architecture, training, and inference details are provided in our supplementary materials." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.742, + 0.717, + 0.758 + ], + "angle": 0, + "content": "3.5. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.765, + 0.892, + 0.81 + ], + "angle": 0, + "content": "Our models are trained on PyTorch [27] using Adam optimizer with hyper-parameters \\((\\beta_{1},\\beta_{2}) = (0.9,0.99)\\). The learning rate is set to \\(10^{-4}\\) in all experiments." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.811, + 0.892, + 0.901 + ], + "angle": 0, + "content": "We train all of our models on an NVIDIA 3090 GPU. It takes about (30, 2, 6) hours in total, (200, 300, 100) epochs with bath sizes of (32, 32, 4) for our three different stages, respectively. During testing, we select all the models with minimum validation loss. We use a sliding window (window size 300, stride 150) for arbitrary long input audio." + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.519, + 0.937 + ], + "angle": 0, + "content": "23024" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.089, + 0.895, + 0.121 + ], + "angle": 0, + "content": "Table 1: Comparisons with state-of-the-art methods. † denotes our generated results with size \\(256 \\times 256\\) through a small renderer. The best results are highlighted in **bold**. The number with **underline** denotes the second-best result." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.131, + 0.894, + 0.328 + ], + "angle": 0, + "content": "
MethodTestset A from LSP [22]Testset B from HDTF [51]
NIQE ↓LMD-v ↓LMD ↓Sync ↑MA ↑NIQE ↓LMD-v ↓LMD ↓Sync ↑MA ↑
MakeItTalk (SIGGRAPH Asia'20 [54])7.072.302.653.070.488.181.912.233.900.53
Wav2Lip (MM'20 [29])7.311.951.815.580.647.832.081.975.780.51
Wav2Lip-GAN (MM'20 [29])7.242.111.835.470.627.772.011.985.780.51
LSP (SIGGRAPH Asia'21 [22])5.752.282.063.090.617.121.672.014.110.52
AD-NeRF (ICCV'21 [10])5.812.892.772.980.41-----
SadTalker (CVPR'23 [50])5.802.512.314.140.567.072.432.373.960.51
GeneFace (ICLR'23 [44])6.612.222.173.080.65-----
Ground Truth (reference)5.280.000.004.891.006.380.000.006.071.00
Ours †5.771.741.514.520.707.051.602.044.340.59
Ours5.551.791.504.480.696.921.591.964.160.56
" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.334, + 0.21, + 0.351 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.359, + 0.268, + 0.376 + ], + "angle": 0, + "content": "4.1. Experimental Setup" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.383, + 0.47, + 0.609 + ], + "angle": 0, + "content": "Dataset pre-processing. We evaluate our method on two publicly available datasets, i.e., HDTF [51] and Video samples from LSP [22] (LSP dataset). Each video contains a high-resolution portrait with an audio track. The average video length is 1-5 minutes and we process them at 25 fps. We randomly select \\(80\\%\\) of them for training and the remaining videos for evaluation. Specifically, we get 132 videos for training and 32 videos for evaluation. Each video is cropped to keep the face at the center and then resized to \\(512 \\times 512\\). The LSP dataset contains 5 different target sequences of 4 different subjects for training and testing. These sequences span a range of 3-5 minutes. All videos are extracted at 25 fps and the synchronized audio is sampled at \\(16K\\mathrm{Hz}\\) frequency. We split videos as \\(80\\% / 20\\%\\) for training and validation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.61, + 0.47, + 0.761 + ], + "angle": 0, + "content": "We detect 478 3D facial landmarks for all videos using Mediapipe*. Then we estimate the head pose \\( H \\) for all videos using method [9]. According to these head poses, the 3D facial landmarks are projected to the canonical space through rigid transformation. We extract the 3D mouth points, and eye-related points as \\( P^M \\) and \\( P^E \\) for each frame. The torso points are estimated from the boundary of the shoulders, which is detected through the face parsing algorithm†. For more data pre-processing details please refer to our supplement materials." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.762, + 0.471, + 0.853 + ], + "angle": 0, + "content": "Evaluation metrics. We demonstrate the superiority of our method on multiple metrics that are widely involved in the talking portrait field. To evaluate the correctness of generated mouth, we use mouth landmark distance (LMD) and velocity of mouth landmark distance (LMD-\\(\\upsilon\\)) between generated video and reference video in canonical space. In" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.33, + 0.892, + 0.721 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.553, + 0.731, + 0.838, + 0.746 + ], + "angle": 0, + "content": "Figure 4: Visual comparison of 5 methods." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.892, + 0.903 + ], + "angle": 0, + "content": "addition, we also calculate the Insertion-over-Union (IoU) for the overlap between the predicted mouth area and the ground truth area (MA). We use the confidence score from SyncNet (Sync) [29] to measure the audio-video synchronization. Since the result cannot be perfectly aligned with the ground-truth video, we use Natural Image Quality Evaluator (NIQE) [24] as the metric for image quality. NIQE is able to capture the naturalness of image details, it is widely used in blind image quality assessment." + }, + { + "type": "page_footnote", + "bbox": [ + 0.078, + 0.863, + 0.442, + 0.901 + ], + "angle": 0, + "content": "\\*https://google.github.io/mediapipe/ \\(\\dagger\\) https://github.com/zllrunning/face-parsing. PyTorch" + }, + { + "type": "footer", + "bbox": [ + 0.479, + 0.925, + 0.519, + 0.937 + ], + "angle": 0, + "content": "23025" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.09, + 0.468, + 0.248 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.083, + 0.257, + 0.462, + 0.273 + ], + "angle": 0, + "content": "Figure 5: Multimodal results with the same mouth shape." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.285, + 0.31, + 0.301 + ], + "angle": 0, + "content": "4.2. Quantitative Comparison" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.309, + 0.473, + 0.626 + ], + "angle": 0, + "content": "We compare our method with several state-of-the-art one-shot talking portrait generation works (LSP [22], MakeItTalk [54], Wav2Lip [29], AD-NeRF [10], SadTalker [50], and GeneFace [44]). For MakeItTalk, Wav2Lip, and SadTalker, the evaluation is performed on their publicly available checkpoint directly. Since these methods only generate low-resolution results, we retrained a small portrait renderer to generate low-resolution results for a fair comparison. The rest methods are retrained on our dataset under the same condition. Note that AD-NeRF and GeneFace are NeRF-based methods that are extremely time-consuming on all videos, we only provide the numerical results on the LSP dataset. As shown in Tab. 1, the proposed method achieves the best overall video quality (lowest NIQE, 5.25) and the correctness of audio-lip synchronization (lowest LMD, LMD-\\(v\\), and highest MA). Our method also shows comparable performance with other fully talking-head generation methods in terms of lip-sync score. Please note that a higher sync score is not always lead to better results since it is too sensitive to the audio where unnatural lip movements may get a better score [50]." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.636, + 0.288, + 0.65 + ], + "angle": 0, + "content": "4.3. Qualitative Evaluation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.659, + 0.47, + 0.87 + ], + "angle": 0, + "content": "User Study. We conduct user studies with 20 attendees on 30 videos generated by ours and the other methods. The driving audio is selected from four different languages: English, Chinese, Japanese, and German. The videos are generated across 5 subjects. Each participant is asked to select the best generated talking-portrait videos based on three major aspects: lip synchronization accuracy, the naturalness of movements including head movement, eye blinking, and upper body movement, and the video quality of the generated portrait. We collect the voting results and calculate the best-voting percentage of each method. The statistics are reported in Tab. 2. Overall, users prefer our results on lip synchronization, the naturalness of portrait, and video quality, indicating the effectiveness of the proposed method." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.469, + 0.901 + ], + "angle": 0, + "content": "Qualitative comparison. Fig. 4 demonstrates the visual comparison among different methods. The results from" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.227 + ], + "angle": 0, + "content": "LSP [22] have some warping effects without 3D consistency. Wav2Lip [29] can generate accurate mouth motions. However, their mouth areas usually have blurry boundaries and artifacts, which make the video unnatural. The results from AD-NeRF [10] have blurry boundaries of shoulders. SadTalker [50] may suffer from out of sync. GeneFace [44] has obvious artifacts on the neck region. Compared to these methods, our system generates portrait videos with overall high-quality and natural mouth movements." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.228, + 0.892, + 0.318 + ], + "angle": 0, + "content": "Diverse outputs. Fig. 5 shows the diverse rendered videos that are driven by the same audio. These videos have different head poses, eye-blinking, and upper bodies while sharing the same mouth structures. These results demonstrate that our MODA network is able to generate vivid and diverse talking portrait videos." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.329, + 0.859, + 0.344 + ], + "angle": 0, + "content": "4.4. Ablation Study and Performance Analysis" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.352, + 0.892, + 0.381 + ], + "angle": 0, + "content": "We conduct ablation studies on dual-attention in MODA, FaCo-Net, and TPE in portrait renderer." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.382, + 0.893, + 0.562 + ], + "angle": 0, + "content": "Dual-attention module. We choose to 1) replace DualAttn with a multi-layer LSTM block [12]; 2) remove the specific attention branch and 3) remove the multimodal attention branch to evaluate the effectiveness of the dual-attention module. Numerical results on LSP test set are reported in Tab. 3. Using LSTM block cannot generate multimodal results and the diverse score (here we use the variance of the generated facial landmarks) drops to 0. When removing the specific attention branch from the dual attention block, the MODA generates the over-smoothed lip movement, which may be out of lip synchronization and has large LMD and LMD-\\(v\\) errors." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.564, + 0.892, + 0.713 + ], + "angle": 0, + "content": "FaCo-Net. The FaCo-Net aims to generate natural and consistent representations for our portrait renderer. We carry out an ablation study on it by removing this stage and directly replacing the eye landmarks and mouth landmarks with facial dense landmarks. Fig. 6a shows that condition images without FaCo-Net contain incorrect connections in the lip area and lose face details, leading to low SSIM \\((0.871\\rightarrow 0.843)\\), PSNR \\((24.77\\rightarrow 21.96)\\) and NIQE \\((5.55\\rightarrow 6.71)\\) rendered images (as in Tab. 4). These results consistently prove the effectiveness of FaCo-Net." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.714, + 0.892, + 0.774 + ], + "angle": 0, + "content": "Temporally positional encoding. We adopt the temporal consistency metric to measure to evaluate the frame-wise consistency (TCM [37]) of the generated videos. Specifically, the TCM is defined as" + }, + { + "type": "equation", + "bbox": [ + 0.511, + 0.786, + 0.892, + 0.827 + ], + "angle": 0, + "content": "\\[\n\\mathrm {T C M} = \\frac {1}{T} \\sum_ {t} ^ {T} \\exp \\left(- \\frac {\\left| \\left| O _ {t} - \\operatorname {w a r p} \\left(O _ {t - 1}\\right) \\right| \\right| ^ {2}}{\\left| \\left| V _ {t} - \\operatorname {w a r p} \\left(V _ {t - 1}\\right) \\right| \\right| ^ {2}} - 1\\right), \\tag {16}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.901 + ], + "angle": 0, + "content": "where \\( O_{t} \\) and \\( V_{t} \\) represent the \\( t^{th} \\) frame in the referenced video (O) and generated video (V), respectively. \\( \\operatorname{warp}(\\cdot) \\) is the warping function using the optical flow [13]. The 2-norm of a matrix \\( ||\\cdot|| \\) is the sum of squares of its elements." + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.519, + 0.936 + ], + "angle": 0, + "content": "23026" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.212, + 0.09, + 0.757, + 0.107 + ], + "angle": 0, + "content": "Table 2: User study analyses measured by best-voting percentage. Higher is better." + }, + { + "type": "table", + "bbox": [ + 0.085, + 0.117, + 0.887, + 0.209 + ], + "angle": 0, + "content": "
ApproachLow resolution (256 × 256)High resolution (512 × 512)
MakeItTalk [54]Wav2lip [29]SadTalker [50]OursLSP [22]AD-NeRF [10]GeneFace [44]Ours
Lip-sync accuracy15.2%30.5%16.5%37.6%24.6%7.9%19.0%48.5%
Naturalness of movement12.8%14.0%18.6%54.5%19.0%6.3%7.1%67.6%
Image quality8.3%7.2%14.3%70.0%22.8%11.1%16.7%49.7%
" + }, + { + "type": "image", + "bbox": [ + 0.084, + 0.221, + 0.329, + 0.304 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.361, + 0.221, + 0.892, + 0.305 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.306, + 0.327, + 0.386 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.36, + 0.306, + 0.892, + 0.389 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.111, + 0.394, + 0.293, + 0.407 + ], + "angle": 0, + "content": "(a) Effectiveness of FaCo-Net." + }, + { + "type": "image_caption", + "bbox": [ + 0.547, + 0.394, + 0.698, + 0.407 + ], + "angle": 0, + "content": "(b) Effectiveness of TPE." + }, + { + "type": "image_caption", + "bbox": [ + 0.216, + 0.42, + 0.752, + 0.436 + ], + "angle": 0, + "content": "Figure 6: Ablation studies on FaCo-Net (a) and temporal positional encoding (b)." + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.46, + 0.468, + 0.491 + ], + "angle": 0, + "content": "Table 3: Ablation study on MODA. Removing dual attention or replacing it with LSTM block has negative effects." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.492, + 0.466, + 0.584 + ], + "angle": 0, + "content": "
MethodLMD-vLMDDiverse
replace with LSTM2.492.790
w/o multimodal attention3.012.810
w/o specific attention1.801.551.70
Final1.791.501.57
" + }, + { + "type": "table_caption", + "bbox": [ + 0.147, + 0.6, + 0.398, + 0.615 + ], + "angle": 0, + "content": "Table 4: Ablation study on FaCo-Net." + }, + { + "type": "table", + "bbox": [ + 0.094, + 0.626, + 0.455, + 0.686 + ], + "angle": 0, + "content": "
MethodSSIM ↑PSNR ↑NIQE ↓
w/o FaCo-Net Net0.84321.966.71
Final0.87124.775.55
" + }, + { + "type": "table_caption", + "bbox": [ + 0.111, + 0.7, + 0.435, + 0.716 + ], + "angle": 0, + "content": "Table 5: Ablation study on TPE. Higher is better." + }, + { + "type": "table", + "bbox": [ + 0.114, + 0.726, + 0.431, + 0.786 + ], + "angle": 0, + "content": "
MethodTCM ↑
Renderer w/o TPE0.63
Renderer with TPE0.71
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.47, + 0.9 + ], + "angle": 0, + "content": "Through this equation, the generated video (V) is encouraged to be temporally consistent according to variations in the reference video (O). Fig. 6b demonstrates the comparison of video sequences with/without TPE. We find TPE can stabilize video synthesis, especially when training videos with changing backgrounds. Numerical results in Tab. 5 also show that TPE can increase TCM score." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.461, + 0.764, + 0.477 + ], + "angle": 0, + "content": "5. Discussions and Conclusions" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.497, + 0.892, + 0.756 + ], + "angle": 0, + "content": "We present a deep learning approach for synthesizing multimodal photorealistic talking-portrait animation from audio streams. Our method can render multiple personalized talking styles with arbitrary audio. Our system contains three stages, i.e., MODA, FaCo-Net, and a high-fidelity portrait renderer with temporal guidance. The first stage generates lip motion, head motion, eye blinking, and torso motion with a unified network. This network adopts a dual-attention mechanism and is able to generate diverse talking-portrait representations with correct lip synchronization. The second stage generates fine-grained facial dense landmarks powered by generated lip motion and eye blinking. Finally, we generate the intermediate representations for our temporal-guided renderer to synthesize both high-fidelity and stable talk-portrait videos. Experimental results and user studies show the superiority of our method. Analytical experiments have also verified different parts of our system." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.893, + 0.902 + ], + "angle": 0, + "content": "Limitations and future work. While our approach achieves impressive results in a wide variety of scenarios, there still exist several limitations. Similar to most deep learning-based methods, our method cannot generalize well on unseen subjects or extremely out-of-domain audio. It may require fine-tuning the renderer for new avatars. We also looking forward to future work to find a person-invariant renderer to achieve high-quality synthesis without additional finetuning." + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.519, + 0.937 + ], + "angle": 0, + "content": "23027" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.175, + 0.107 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.117, + 0.47, + 0.158 + ], + "angle": 0, + "content": "[1] Iz Beltagy, Matthew E Peters, and Arman Cohan. Longformer: The long-document transformer. arXiv preprint arXiv:2004.05150, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.16, + 0.47, + 0.202 + ], + "angle": 0, + "content": "[2] Lele Chen, Guofeng Cui, Celong Liu, Zhong Li, Ziyi Kou, Yi Xu, and Chenliang Xu. Talking-head generation with rhythmic head motion. In ECCV, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.204, + 0.47, + 0.247 + ], + "angle": 0, + "content": "[3] Lele Chen, Ross K. Maddox, Zhiyao Duan, and Chenliang Xu. Hierarchical cross-modal talking face generation with dynamic pixel-wise loss. In CVPR, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.249, + 0.47, + 0.289 + ], + "angle": 0, + "content": "[4] Joon Son Chung, Andrew Senior, Oriol Vinyals, and Andrew Zisserman. Lip reading sentences in the wild. In CVPR, 2017. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.292, + 0.47, + 0.334 + ], + "angle": 0, + "content": "[5] Pif Edwards, Chris Landreth, Eugene Fume, and Karan Singh. Jali: an animator-centric viseme model for expressive lip synchronization. TOG, 35(4):1-11, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.336, + 0.47, + 0.378 + ], + "angle": 0, + "content": "[6] Yingruo Fan, Zhaojiang Lin, Jun Saito, Wenping Wang, and Taku Komura. Faceformer: Speech-driven 3d facial animation with transformers. In CVPR, 2022. 1, 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.379, + 0.47, + 0.421 + ], + "angle": 0, + "content": "[7] Guy Gafni, Justus Thies, Michael Zollhofer, and Matthias Nießner. Dynamic neural radiance fields for monocular 4d facial avatar reconstruction. In CVPR, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.423, + 0.47, + 0.478 + ], + "angle": 0, + "content": "[8] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In NeurIPS, 2014. 1, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.481, + 0.47, + 0.523 + ], + "angle": 0, + "content": "[9] Jianzhu Guo, Xiangyu Zhu, Yang Yang, Fan Yang, Zhen Lei, and Stan Z Li. Towards fast, accurate and stable 3d dense face alignment. In ECCV, 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.525, + 0.47, + 0.58 + ], + "angle": 0, + "content": "[10] Yudong Guo, Keyu Chen, Sen Liang, Yong-Jin Liu, Hujun Bao, and Juyong Zhang. Ad-nerf: Audio driven neural radiance fields for talking head synthesis. In ICCV, 2021. 2, 6, 7, 8, 12, 14" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.582, + 0.47, + 0.638 + ], + "angle": 0, + "content": "[11] Kai Han, Yunhe Wang, Hanting Chen, Xinghao Chen, Jianyuan Guo, Zhenhua Liu, Yehui Tang, An Xiao, Chunjing Xu, Yixing Xu, et al. A survey on vision transformer. PAMI, 45(1):87-110, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.64, + 0.47, + 0.668 + ], + "angle": 0, + "content": "[12] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 9(8):1735-1780, 1997. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.67, + 0.47, + 0.698 + ], + "angle": 0, + "content": "[13] Berthold KP Horn and Brian G Schunck. Determining optical flow. Artificial intelligence, 17(1-3):185–203, 1981. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.7, + 0.47, + 0.755 + ], + "angle": 0, + "content": "[14] Xinya Ji, Hang Zhou, Kaisiyuan Wang, Qianyi Wu, Wayne Wu, Feng Xu, and Xun Cao. Eamm: One-shot emotional talking face via audio-based emotion-aware motion model. In SIGGRAPH, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.758, + 0.47, + 0.813 + ], + "angle": 0, + "content": "[15] Tero Karras, Timo Aila, Samuli Laine, Antti Herva, and Jaakko Lehtinen. Audio-driven facial animation by joint end-to-end learning of pose and emotion. TOG, 36(4):1-12, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.816, + 0.47, + 0.87 + ], + "angle": 0, + "content": "[16] Salman Khan, Muzammal Naseer, Munawar Hayat, Syed Waqas Zamir, Fahad Shahbaz Khan, and Mubarak Shah. Transformers in vision: A survey. arXiv preprint arXiv:2101.01169, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[17] D. P. Kingma and M. Welling. Auto-encoding variational bayes. In ICLR, 2014. 5" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.117, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[18] Prajwal KR, Rudrabha Mukhopadhyay, Jerin Philip, Abhishek Jha, Vinay Namboodiri, and CV Jawahar. Towards automatic face-to-face translation. In ACMMM, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.189 + ], + "angle": 0, + "content": "[19] Avisek Lahiri, Vivek Kwatra, Christian Frueh, John Lewis, and Chris Bregler. Lipsync3d: Data-efficient learning of personalized 3d talking faces from video using pose and lighting normalization. In CVPR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.191, + 0.892, + 0.231 + ], + "angle": 0, + "content": "[20] Ming-Yu Liu, Thomas Breuel, and Jan Kautz. Unsupervised image-to-image translation networks. In NeurIPS, 2017. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.233, + 0.892, + 0.286 + ], + "angle": 0, + "content": "[21] Xian Liu, Yinghao Xu, Qianyi Wu, Hang Zhou, Wayne Wu, and Bolei Zhou. Semantic-aware implicit neural audio-driven video portrait generation. In ECCV. Springer, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.288, + 0.892, + 0.329 + ], + "angle": 0, + "content": "[22] Yuanxun Lu, Jinxiang Chai, and Xun Cao. Live speech portraits: real-time photorealistic talking-head animation. TOG, 40(6):1-17, 2021. 1, 2, 3, 6, 7, 8, 11, 12, 14" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.33, + 0.892, + 0.357 + ], + "angle": 0, + "content": "[23] Larry R Medsker and LC Jain. Recurrent neural networks. Design and Applications, 5:64-67, 2001. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.359, + 0.892, + 0.399 + ], + "angle": 0, + "content": "[24] Anish Mittal, Rajiv Soundararajan, and Alan C Bovik. Making a \"completely blind\" image quality analyzer. IEEE Signal processing letters, 20(3):209-212, 2012. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.401, + 0.892, + 0.442 + ], + "angle": 0, + "content": "[25] Se Jin Park, Minsu Kim, Joanna Hong, Jeongsoo Choi, and Yong Man Ro. Synctalkface: Talking face generation with precise lip-syncing via audio-lip memory. In AAAI, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.443, + 0.892, + 0.482 + ], + "angle": 0, + "content": "[26] Razvan Pascanu, Tomas Mikolov, and Yoshua Bengio. On the difficulty of training recurrent neural networks. In ICML, 2013. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.484, + 0.892, + 0.551 + ], + "angle": 0, + "content": "[27] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, et al. Pytorch: An imperative style, high-performance deep learning library. NeurlPS, 32, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.553, + 0.892, + 0.594 + ], + "angle": 0, + "content": "[28] Mathis Petrovich, Michael J Black, and Gül Varol. Action-conditioned 3d human motion synthesis with transformer vae. arXiv preprint arXiv:2104.05670, 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.596, + 0.892, + 0.649 + ], + "angle": 0, + "content": "[29] KR Prajwal, Rudrabha Mukhopadhyay, Vinay P Namboodiri, and CV Jawahar. A lip sync expert is all you need for speech to lip generation in the wild. In ACMMM, 2020. 1, 2, 6, 7, 8, 12" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.651, + 0.892, + 0.704 + ], + "angle": 0, + "content": "[30] Steffen Schneider, Alexei Baevski, Ronan Collobert, and Michael Auli. Wav2vec: Unsupervised pre-training for speech recognition. arXiv preprint arXiv:1904.05862, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.707, + 0.892, + 0.748 + ], + "angle": 0, + "content": "[31] Oliver Schreer, Roman Englert, Peter Eisert, and Ralf Tanger. Real-time vision and speech driven avatars for multimedia applications. TMM, 10(3):352-360, 2008. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.749, + 0.892, + 0.802 + ], + "angle": 0, + "content": "[32] Shuai Shen, Wenliang Zhao, Zibin Meng, Wanhua Li, Zheng Zhu, Jie Zhou, and Jiwen Lu. Difftalk: Crafting diffusion models for generalized talking head synthesis. arXiv preprint arXiv:2301.03786, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.804, + 0.892, + 0.845 + ], + "angle": 0, + "content": "[33] Aliaksandr Siarohin, Stéphane Lathuilière, Sergey Tulyakov, Elisa Ricci, and Nicu Sebe. First order motion model for image animation. NeurIPS, 32, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.847, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[34] Michal Stypulkowski, Konstantinos Vougioukas, Sen He, Maciej Zięba, Stavros Petridis, and Maja Pantic. Diffused heads: Diffusion models beat gans on talking-face generation. arXiv preprint arXiv:2301.03396, 2023. 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.52, + 0.937 + ], + "angle": 0, + "content": "23028" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[35] Anni Tang, Tianyu He, Xu Tan, Jun Ling, Runnan Li, Sheng Zhao, Li Song, and Jiang Bian. Memories are one-to-many mapping alleviators in talking face generation. arXiv preprint arXiv:2212.05005, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.149, + 0.468, + 0.189 + ], + "angle": 0, + "content": "[36] Justus Thies, Mohamed Elgharib, Ayush Tewari, Christian Theobalt, and Matthias Nießner. Neural voice puppetry: Audio-driven facial reenactment. In ECCV, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.191, + 0.468, + 0.245 + ], + "angle": 0, + "content": "[37] S. Varghese, Y. Bayzidi, A. Bar, N. Kapoor, and T. Fingscheidt. Unsupervised temporal consistency metric for video segmentation in highly-automated driving. In CVPR Workshop, 2020. 7, 11" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.247, + 0.468, + 0.287 + ], + "angle": 0, + "content": "[38] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In NeurIPS, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.289, + 0.468, + 0.342 + ], + "angle": 0, + "content": "[39] Kaisiyuan Wang, Qianyi Wu, Linsen Song, Zhuoqian Yang, Wayne Wu, Chen Qian, Ran He, Yu Qiao, and Chen Change Loy. Mead: A large-scale audio-visual dataset for emotional talking-face generation. In ECCV, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.344, + 0.468, + 0.384 + ], + "angle": 0, + "content": "[40] Suzhen Wang, Lincheng Li, Yu Ding, Changjie Fan, and Xin Yu. Audio2head: Audio-driven one-shot talking-head generation with natural head motion. In *IJCAI*, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.386, + 0.468, + 0.426 + ], + "angle": 0, + "content": "[41] Ting-Chun Wang, Ming-Yu Liu, Jun-Yan Zhu, Guilin Liu, Andrew Tao, Jan Kautz, and Bryan Catanzaro. Video-to-video synthesis. In NeurIPS, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.428, + 0.468, + 0.469 + ], + "angle": 0, + "content": "[42] Xinsheng Wang, Qicong Xie, Jihua Zhu, Lei Xie, et al. Anyonenet: Synchronized speech and talking head generation for arbitrary person. arXiv preprint arXiv:2108.04325, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.47, + 0.468, + 0.524 + ], + "angle": 0, + "content": "[43] Shunyu Yao, RuiZhe Zhong, Yichao Yan, Guangtao Zhai, and Xiaokang Yang. Dfa-nerf: Personalized talking head generation via disentangled face attributes neural rendering. arXiv preprint arXiv:2201.00791, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.526, + 0.468, + 0.579 + ], + "angle": 0, + "content": "[44] Zhenhui Ye, Ziyue Jiang, Yi Ren, Jinglin Liu, JinZheng He, and Zhou Zhao. Geneface: Generalized and high-fidelity audio-driven 3d talking face synthesis. In ICLR, 2023. 1, 2, 4, 6, 7, 8, 14" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.581, + 0.468, + 0.635 + ], + "angle": 0, + "content": "[45] Ran Yi, Zipeng Ye, Juyong Zhang, Hujun Bao, and Yong-Jin Liu. Audio-driven talking face video generation with learning-based personalized head pose. arXiv preprint arXiv:2002.10137, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.637, + 0.468, + 0.677 + ], + "angle": 0, + "content": "[46] Zili Yi, Hao Zhang, Ping Tan, and Minglun Gong. Dualgan: Unsupervised dual learning for image-to-image translation. In ICCV, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.679, + 0.468, + 0.732 + ], + "angle": 0, + "content": "[47] Changqian Yu, Changxin Gao, Jingbo Wang, Gang Yu, Chunhua Shen, and Nong Sang. Bisenet v2: Bilateral network with guided aggregation for real-time semantic segmentation. IJCV, 129:3051-3068, 2021. 12" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.735, + 0.468, + 0.774 + ], + "angle": 0, + "content": "[48] Egor Zakharov, Aliaksandra Shysheya, Egor Burkov, and Victor Lempitsky. Few-shot adversarial learning of realistic neural talking head models. In ICCV, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.776, + 0.468, + 0.83 + ], + "angle": 0, + "content": "[49] Chenxu Zhang, Yifan Zhao, Yifei Huang, Ming Zeng, Saifeng Ni, Madhukar Budagavi, and Xiaohu Guo. Facial: Synthesizing dynamic talking face with implicit attribute learning. In ICCV, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.832, + 0.468, + 0.899 + ], + "angle": 0, + "content": "[50] Wenxuan Zhang, Xiaodong Cun, Xuan Wang, Yong Zhang, Xi Shen, Yu Guo, Ying Shan, and Fei Wang. Sadtalker: Learning realistic 3d motion coefficients for stylized audio-driven single image talking face animation. In CVPR, 2023. 1, 2, 3, 6, 7, 8" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[51] Zhimeng Zhang, Lincheng Li, Yu Ding, and Changjie Fan. Flow-guided one-shot talking face generation with a high-resolution audio-visual dataset. In CVPR, 2021. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.137, + 0.892, + 0.189 + ], + "angle": 0, + "content": "[52] Hang Zhou, Yasheng Sun, Wayne Wu, Chen Change Loy, Xiaogang Wang, and Ziwei Liu. Pose-controllable talking face generation by implicitly modularized audio-visual representation. In CVPR, 2021. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.192, + 0.892, + 0.233 + ], + "angle": 0, + "content": "[53] Yijun Zhou and James Gregson. Whenet: Real-time fine-grained estimation for wide range head pose. arXiv preprint arXiv:2005.10353, 2020. 11" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.235, + 0.892, + 0.289 + ], + "angle": 0, + "content": "[54] Yang Zhou, Xintong Han, Eli Shechtman, Jose Echevarria, Evangelos Kalogerakis, and Dingzeyu Li. Makelttalk: speaker-aware talking-head animation. TOG, 39(6):1-15, 2020. 1, 2, 3, 6, 7, 8, 12" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.291, + 0.892, + 0.345 + ], + "angle": 0, + "content": "[55] Yang Zhou, Zhan Xu, Chris Landreth, Evangelos Kalogerakis, Subhransu Maji, and Karan Singh. Visemenet: Audio-driven animator-centric speech animation. TOG, 37(4):1-10, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.348, + 0.892, + 0.389 + ], + "angle": 0, + "content": "[56] Hao Zhu, Huaibo Huang, Yi Li, Aihua Zheng, and Ran He. Arbitrary talking face generation via attentional audio-visual coherence learning. In IJCAI, 2020. 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.389 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.519, + 0.937 + ], + "angle": 0, + "content": "23029" + } + ] +] \ No newline at end of file diff --git a/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/cd6d82fe-3030-4ffc-8902-e0f3febe9ace_origin.pdf b/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/cd6d82fe-3030-4ffc-8902-e0f3febe9ace_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..32d754c434ef8ff6864a7f929ebbb857652031e8 --- /dev/null +++ b/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/cd6d82fe-3030-4ffc-8902-e0f3febe9ace_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:ff3a3f002f007461364d2a5d42c575be1bb5d539bec4b1db20b7cbea0ecc6e48 +size 2260808 diff --git a/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/full.md b/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/full.md new file mode 100644 index 0000000000000000000000000000000000000000..0e0f3c7fea98fa05839bff7032bf5e6d8f357a33 --- /dev/null +++ b/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/full.md @@ -0,0 +1,341 @@ +# MODA: Mapping-Once Audio-driven Portrait Animation with Dual Attentions + +Yunfei Liu1 Lijian Lin1 Fei Yu2 Changyin Zhou2 Yu Li1* 1International Digital Economy Academy (IDEA) 2Vstring Inc. https://tinyurl.com/iccv23-modala + +![](images/bbaaec040456d9d6ae7cce19783479400bdfff4903c90b1a381964923e40ffa0.jpg) +Figure 1: We propose a mapping-once system with dual-attention for multimodal and high-fidelity portrait video animation. + +# Abstract + +Audio-driven portrait animation aims to synthesize portrait videos that are conditioned by given audio. Animating high-fidelity and multimodal video portraits has a variety of applications. Previous methods have attempted to capture different motion modes and generate high-fidelity portrait videos by training different models or sampling signals from given videos. However, lacking correlation learning between lip-sync and other movements (e.g., head pose/eye blinking) usually leads to unnatural results. In this paper, we propose a unified system for multi-person, diverse, and high-fidelity talking portrait generation. Our method contains three stages, i.e., 1) Mapping-Once network with Dual Attentions (MODA) generates talking representation from given audio. In MODA, we design a dual-attention module to encode accurate mouth movements and diverse modalities. 2) Facial composer network generates dense and detailed face landmarks, and 3) temporal-guided renderer syntheses stable videos. Extensive evaluations demonstrate that the proposed system produces more natural and realistic video portraits compared to previous methods. + +# 1. Introduction + +Given an input audio, talking portrait animation is to synthesize video frames of a person whose poses and expressions are synchronized with the audio signal [2, 3, 4, 18]. This audio-driven portrait video generation task has gained increasing attention recently and has a wide range of applications in digital avatars, gaming, telepresence, virtual reality (VR), video production etc. Conventional portrait video generation consumes intensive labor and time during setting up the background, make-up, lighting, shooting, and editing. Moreover, a re-shot is always required when there exists new textual content. In contrast, audio-driven talking video generation is more convenient and attractive which only requires a new audio clip to render a new video. + +Previous methods [7, 29, 52] try to learn the correspondence between audio and frames. However, these methods usually ignore the head pose as it is hard to separate head posture from facial movement. Many 3D face reconstruction algorithm-based and GAN-based [8] methods estimate intermediate representations, such as 3D face shapes [6, 50], 2D landmarks [22, 54], or face expression parameters [49], to assist the generation process. However, such sparse representations usually lost facial details, leading to over-smooth [44]. Recently, the neural radiance field + +(NeRF) [10, 44] has been widely applied in talking head generation for high-fidelity results. However, the implicit neural representation is hard to interpret and control. In addition, these methods are usually person-specific and require extra training or adaptation time for different persons. + +Although quite a number of attempts and progresses have been made in recent years, it is still challenging to generate realistic and expressive talking videos. As humans are extremely sensitive to identifying the artifacts in the synthesized portrait videos, it sets a very high standard for this technique to become applicable. We summarize the following key points that affect human perceptions: 1) Correctness. The synthesized talking portrait video should be well synchronized with the driven audio. 2) Visual quality. The synthesized video should have high resolution and contain fine detail components. 3) Diversity. Besides the lip motion needing to be exactly matched to the audio content, the motion of other components like eye blinking and head movement are not deterministic. They should move naturally as a natural human does. + +To achieve these goals, previous approaches either map the mouth landmarks and the head pose separately by learning different sub-networks [22, 50], or only model the mouth movement while the head pose is obtained from the existing video [29, 52]. However, lacking correlation learning between lip-sync and other movements usually leads to unnatural results. In this paper, we propose a mapping-once network with dual attentions (MODA), which is a unified architecture to generate diverse representations for a talking portrait, simplifying the computational steps. In order to combine synchronization and diversity of the talking portrait generation, we carefully design a dual-attention module to learn deterministic mappings (i.e., the accurate mouth movements driven by audio) and probabilistic sampling (i.e., the diverse head pose/eye blinking from time-to-time), respectively. To summarize, our contributions can be listed as follows: + +- We propose a talking portrait system that generates multimodal photorealistic portrait videos with accurate lip motion. Comprehensive evaluations demonstrate our system can achieve state-of-the-art performance. +- We propose a unified mapping-once with dual attention (MODA) network for generating portrait representation from subject conditions and arbitrary audio. +- We propose 3 technical points for taking portrait generation: 1) A transformer-based dual attention module for generating both specific and diverse representations. 2) A facial composer network to get accurate and detailed facial landmarks. 3) A temporally guided renderer to synthesize videos with both high quality and temporal stabilization. + +# 2. Related Works + +Audio-driven portrait animation. Talking heads and facial animation are research hot-spots in the computer vision community. Extensive approaches [5, 55] explore audio-driven mouth animation and audio-driven facial animation. We focus on animating a portrait in this work. Many methods [4, 5, 29, 31, 56] aim to find the correspondence between audio and frames. A large number of technologies (such as flow-learning [14, 40, 51], memory bank [25, 35], etc.) are explored for the correctness of talking head generation. However, these methods usually ignore the head pose, torso motion, and eye blinking, which are essential for a natural talking portrait generation. To generate diverse talking heads, recent methods [19, 52] propose to embed other modalities to control emotions or head pose. However, these methods usually require additional inputs. + +Recently, neural radiance field (NeRF) [10] has been widely applied in 3D-related tasks as it can accurately reproduce complex scenes with implicit neural representation. Several works [10, 43, 21, 44] leverage NeRF to represent faces with audio features as conditions. Despite the high-quality results achieved, the motion of generated results is usually unnatural. Besides, the learning and inference processes are time-consuming. More recently, some diffusion-based methods [32, 34] are proposed to generate talking heads. However, their speed is limited by a large number of sampling steps in the diffusion process. Some methods are based on the 3D face reconstruction and GAN [15, 22, 45]. They estimate intermediate representations such as 2D landmarks [39, 48, 54], 3D face shapes [15, 36] or facial expression parameters [42, 50], to assist the generation process. Unfortunately, such sparse representation usually lost facial details. In this paper, we propose to learn dense facial landmarks and upper body points through a unified framework for talking portrait generation. The intermediate representation contains facial details and other movements, which can be interpreted and controlled easily. + +Transformers in audio-driven tasks. Transformer [38] is a strong alternative to both RNN and CNN. Researchers find it works well in multimodal scenarios. We refer readers to the comprehensive survey [16] for further information. Some recent works adopt transformers to generate results from different modalities, such as audio-to-text, language translation, music-to-dance, etc. The most related work is FaceFormer [6], which is a speech-driven 3D facial animation approach. They proposed two types of bias for the transformer to better align audio and 3D face animation. + +Vision-based facial reenactment. Video-based facial reenactment is another technique related to audio-driven animation [33, 31]. There are many works to reenact faces with different techniques, such as adversarial learning, few-shot learning, or even one-shot facial animation. They usually adopt pre-defined facial landmarks or in an unsupervised + +![](images/e2a46c4d52521b48a864f66a273f9e15275813ec0d466a2e1f4c70456137f8b3.jpg) +Figure 2: The proposed method is a three-stage system. Given the subject figure and arbitrary audio, the proposed system generates audio-driven video. Here $\mathbb{O}$ denotes rigid transformation from canonical space to camera coordinate via head pose, $\odot$ denotes concatenation. $\mathbb{P}$ is projection from 3D space to image coordinate. FaCo-Net is a facial composer network, which will be introduced in Sec. 3.3. + +scheme. In another aspect, image-to-image translation (I2I) methods [20, 46] have also demonstrated impressive performance in converting images from one domain to another. However, single-frame renderers [20] ignore the temporal relations among video frames, leading to color jitters or unnatural background shakes in the final results. [41] proposes to use RNN [23] to capture the temporal relations among the input conditions, which generates stabilized results. However, these methods have difficulties in training [26]. In this paper, we find an alternative way to embed temporal information into I2I. Simply using temporal positional embedding [11] as an input condition, our method can achieve natural and stabilized results. + +# 3. Methodology + +We present a talking portrait system for high-fidelity portrait video generation with accurate lip motion and multimodal motions, including head pose, eye blinking, and torso movements. The overall pipeline of this system is illustrated in Fig. 2. It contains three stages, 1) given the driven audio and conditioned subjects, mapping once talking portrait network with dual attentions (MODA) generates multimodal and correct semantic portrait components, 2) in the next, the facial composer network combines the facial components together and adds details for dense facial vertices, and 3) finally, a portrait renderer with temporally positional embedding (TPE) syntheses high-fidelity and stable videos. + +# 3.1. Task Definition + +In this section, we give the definition of the talking portrait task, which is to formulate a sequence-to-sequence translation manner [1] from talking portrait videos. Specifically, given a $T$ -length audio sequence $\mathbf{A} = \{a_0, a_1, \dots, a_T\}$ with audio sampling rate $r$ , a talking portrait method aims to map it into the corresponding video clip $\mathbf{V} = \{I_0, I_1, \dots, I_K\}$ with $f$ frame-per-second (FPS), where $K = \lfloor fT / r \rfloor$ . Since the data dimension of $\mathbf{V}$ is much larger than $\mathbf{A}$ , many researchers propose to generate $\mathbf{V}$ progressively and introduce many types of intermediate + +representation $\mathbf{R}$ . To make the generated $\mathbf{V}$ look natural, the constraint on $\mathbf{R}$ is critical. In previous audio-driven face animation approaches, $\mathbf{R}$ typically represents one type of face information, such as facial landmarks [22, 54] or head pose [50]. To better represent a talking portrait, we define $\mathbf{R}$ as the union of different portrait descriptors, i.e., $\mathbf{R} = \{P^M, P^E, P^F, H, P^T\}$ , where the elements of $\mathbf{R}$ are defined as follows, + +1. Mouth points $P^M \in \mathbb{R}^{40 \times 3}$ . They have 40 points for representing mouth animation. +2. Eyes points $P^{E} \in \mathbb{R}^{60 \times 3}$ . They consist of eye and eyebrow points, which control eye blinking. +3. Facial points $P^{F} \in \mathbb{R}^{478 \times 3}$ . They contain dense facial 3D points for recording expression details. +4. Head pose $H \in \mathbb{R}^6$ . It contains head rotations $(\theta, \phi, \psi)$ in Euler angle and head transposes $(x, y, z)$ in Euclidean space). +5. Torso points $P^T \in \mathbb{R}^{18 \times 3}$ . They contain 18 points and each side of the shoulder is described by 9 points. + +Note that $P^M, P^E$ , and $P^F$ are in canonical space for the convenience of face alignment. The process of talking portrait can be rewritten as $\mathbf{A} \rightarrow \mathbf{R} \rightarrow \mathbf{V}$ . We design corresponding networks for these stages, respectively. The details are provided in the following subsections. + +# 3.2. Mapping-Once Network with Dual Attentions + +Mapping-once architecture. Given the driven audio A and subject condition S, MODA aims to map them into R (consists of lip movement, eye blinking, head pose, and torso) with a single forward process. As illustrated in Fig. 3, the network in the first step contains three parts, i.e., 1) two encoders for encoding audio features and extracting subject style, respectively, 2) a dual-attention module for generating diverse but accurate motion features, and 3) four tails for different motion synthesis. We first extract contextual features of the audio signal by Wav2Vec [30]. In the next, the extracted feature is projected into $s_a \in \mathbb{R}^{d \times T}$ via a multilayer perceptron (MLP), where $d$ is the feature dimension for one frame and $T$ denotes the number of frames of the + +![](images/6e31bd9ac8c9ffa51adb6cba4928567840ea8f60b69124b2059dcbb9e3f596ee.jpg) +Figure 3: Architecture of MODA network. Given an audio and subject condition, MODA generates four types of motions within a single forward process. $\oplus$ denotes element-wise addition and $\odot$ is concatenation. + +generated video. To model different speaker styles, we take the facial vertices of the conditioned subject as input. Then those vertices are projected to a $d$ -dimensional vector $v_{s}$ as the subject style code. Here the embedding layer is implemented by MLP. Next, $s_a$ and $v_{s}$ are combined as: + +$$ +s = s _ {a} \oplus \operatorname {t i l e} \left(v _ {s}\right), \tag {1} +$$ + +where $s$ is the combined feature, $\oplus$ is dimension-wise addition. Then the dual-attention module (DualAttn) takes $s$ , $s_a$ as input, and yields a temporally contextual version $s_t$ , + +$$ +s _ {t} = \operatorname {D u a l A t t n} (s, s _ {a}). \tag {2} +$$ + +Next, we adopt 4 MLPs to decode the movements of lips $P^{M}$ , head pose $H$ , eye blinking $P^{E}$ , and torso $P^{S}$ , respectively. For each downstream task $X$ , the computational process can be formulated as follows, + +$$ +\Delta X = \Phi^ {X} \left(s _ {t}\right), \tag {3} +$$ + +where $\Phi (\cdot)$ denotes an MLP and $\Delta X = X - \overline{X}$ , $\overline{X}$ is extracted from referred subject image. + +Dual-attention module. The talking portrait generation task is highly ill-posed since it requires generating multimodal results from limited-driven information. To solve this, we propose a dual-attention module that disentangles this task into a specific mapping and a probabilistic mapping problem. Specifically, this module generates 1) the temporally aligned feature for specific mapping between audio and lip movements, as well as 2) the temporally correlated feature for probabilistic mapping between audio and other movements of the talking portrait. To this end, we first design two sub-modules to learn these two different features, respectively. Then we fuse these two features via time-wise concatenation. + +In detail, we propose a specific attention branch (SpecAttn) to capture the temporally aligned attention + +$s_{sa}$ between $s$ and audio feature $s_a$ . Inspired by FaceFormer [6], our SpecAttn is formulated as: + +$$ +\begin{array}{l} s _ {s a} = \operatorname {S p e c A t t n} \left(s _ {a}, s\right) \\ = \operatorname {s o f t m a x} \left(\frac {\Gamma (s) \cdot s _ {a} ^ {T}}{\sqrt {d}} + M _ {A}\right) \Gamma (s), \tag {4} \\ \end{array} +$$ + +where $d$ is the dimension of $s_a, \{\cdot\}^T$ indicates the transpose of the input parameter. The alignment bias $M_A(1 \leq i \leq T, 1 \leq j \leq T)$ is represented as: + +$$ +M _ {A} (i, j) = \left\{ \begin{array}{l l} 0, & i = j \\ - \infty , & \text {o t h e r w i s e .} \end{array} \right. \tag {5} +$$ + +Different from FaceFormer which performs cross-attention in an auto-regressive manner, we apply this operation on the entire sequence, which boosts the computation speed $T \times$ faster. In addition, to capture rich temporal information, we adopt a periodic positional encoding (PPE) and a biased casual self-attention on $s$ (as in [6]): + +$$ +s ^ {\prime} = \Gamma (s) = \operatorname {s o f t m a x} \left(\frac {\mathrm {P P E} (s) \cdot \mathrm {P P E} (s) ^ {T}}{\sqrt {d}} + M _ {T}\right) \mathrm {P P E} (s). \tag {6} +$$ + +$M_T$ is a matrix that has negative infinity in the upper triangle to avoid looking at future frames to make current predictions. $M_T$ is defined as: + +$$ +M _ {T} (i, j) = \left\{ \begin{array}{l l} \lfloor (i - j) q \rfloor , & j \leq i, \\ - \infty , & \text {o t h e r w i s e}, \end{array} \right. \tag {7} +$$ + +where $q$ is a hyper-parameter for tuning the sequence period. By doing this, the encoded feature $s'$ contains rich spatial-temporal information, which aids the accurate talking portrait generation. + +To generate vivid results and avoid the oversmoothing [44] representations, it is essential to learn the probabilistic mapping between the audio feature and portrait motions. We notice that Variational Autoencoder + +(VAE) [17] can model probabilistic synthesis and shows many advanced performances in sequence generation tasks. Therefore, based on an advanced transformer Variational Autoencoder (t-VAE) [28], we design a probabilistic attention branch to generate diverse results. Formally, given the representation $s$ , the probabilistic attention (ProbAttn) aims to generate a diverse feature $s_{pa}$ . It first models the distribution of $s$ with learned $\mu$ and $\sigma$ through an encoder (Enc). Then it generates multimodal outputs through a re-sample operation with a decoder (Dec). The computational process is + +$$ +\mu , \log \sigma = \Phi^ {\mu} (\operatorname {E n c} (s)), \Phi^ {\sigma} (\operatorname {E n c} (s)), \tag {8} +$$ + +$$ +s _ {p a} = \operatorname {D e c} (x), \text {s . t .} x \sim \mathcal {U} (\mu , \sigma), +$$ + +where $\Phi$ is an MLP. $\mathcal{U}(\mu, \sigma)$ is the Gaussian distribution with mean $\mu$ and variance $\sigma$ . To force ProbAttn to learn diverse motion styles, we add Kullback-Leibler divergence (KLD) loss to constrain the feature from the bottleneck of t-VAE. The KLD loss is defined as follows: + +$$ +\mathcal {L} _ {K L D} = \left(- \frac {1}{2 d _ {l}} \sum^ {d _ {l}} (\log \sigma - \mu^ {2} - \sigma + 1), \right. \tag {9} +$$ + +where $d_{l}$ is the dimension of $\mu$ . Finally, the dual-attention module outputs $s_{t} = s_{sa} \odot s_{pa}$ for downstream tasks. + +Loss functions. The MODA has four decoders for generating talking portrait-related motions. To learn the mapping from the dual-attention module and four different types of motion, we adopt a multi-task learning scheme for MODA. Specifically, we minimize the $L_{1}$ distance between the ground-truth displacements and the predicted displacements. The loss can be written as + +$$ +\begin{array}{l} \mathcal {L} _ {T P} = \lambda_ {1} \left| \Delta P _ {g t} ^ {M} - \Delta P ^ {M} \right| + \lambda_ {2} \left| \Delta R _ {g t} - \Delta R \right| \tag {10} \\ + \lambda_ {3} | \Delta P _ {g t} ^ {E} - \Delta P ^ {E} | + \lambda_ {4} | \Delta P _ {g t} ^ {S} - \Delta P ^ {S} |, \\ \end{array} +$$ + +where $\lambda_1, \lambda_2, \lambda_3, \lambda_4$ are hyper-parameters for balancing the different weights of downstream tasks. $|\cdot|$ is the $L_{1}$ -norm. $\Delta P_{gt}^{*}$ and $\Delta P^{*}$ indicate the displacements of the ground truth and the predicted result, respectively. The total loss function is the sum of $\mathcal{L}_{TP}$ and $\mathcal{L}_{KLD}$ , i.e., + +$$ +\mathcal {L} _ {\text {t o t a l}} = \mathcal {L} _ {T P} + \mathcal {L} _ {K L D}. \tag {11} +$$ + +# 3.3. FacialComposerNetwork + +Given the subject information $\mathbf{S}$ , the generated mouth points $P^{M}$ , and eye points $P^{E}$ , the facial composer network (FaCo-Net) aims to compose the refined facial dense landmarks. The generated facial dense landmarks $P^{F} = \mathrm{FaCo - Net}(\mathbf{S}, P^{M}, P^{E})$ . FaCo-Net consists of three encoders for consuming those three inputs and a decoder for facial landmarks generation. Similar to MODA, the subject encoder projects facial points $\mathbf{S}$ into a style code $\pmb{p}_{f}$ . The + +$P^{M}$ and $P^{E}$ are also projected to $\pmb{p}_{m}$ and $\pmb{p}_{e}$ , which share the same latent space as $\pmb{p}_{f}$ . Next, $P^{F} = \Psi_{c}((\pmb{p}_{m} \odot \pmb{p}_{e}) \oplus \pmb{p}_{f})$ , where $\Psi_{c}$ is a facial dense point decoder. We adopt a vanilla GAN architecture [8] as the backbone of the discriminator $(D)$ . The FaCo-Net is trained to generate "realistic" facial dense points to fool $D$ , whereas $D$ is trained to distinguish the generated facial points from ground truths. The detailed architectures can be found in the supplementary materials. We use LSGAN loss [20] as the adversarial loss to optimize the D: + +$$ +\mathcal {L} _ {\text {D i s c}} (D) = (z - 1) ^ {2} + \hat {z} ^ {2}, \tag {12} +$$ + +where $z, \hat{z}$ is the discriminator output when inputting the ground-truth face points $P_{gt}^{F}$ and the generated $P^{F}$ , respectively. The loss for the generator is + +$$ +\mathcal {L} _ {G} = \mathcal {L} _ {G A N} (\text {F a C o - N e t}) + \lambda \left| P _ {g t} ^ {F} - P ^ {F} \right|, \tag {13} +$$ + +where $P_{gt}^{F}$ is the ground-truth dense face landmarks. $\mathcal{L}_{GAN}(\mathrm{FaCo - Net}) = (\hat{z} -1)^2$ is the adversarial loss, where $\hat{z} = D(P^F)$ . The weight $\lambda$ is empirically set to 10. After composition, the facial landmarks $P^{F}$ are transformed to the camera coordinate via head pose $H$ . The transformed facial landmarks and torso points $P^T$ are projected into image space for photorealistic rendering. + +# 3.4. Portrait Image Synthesis with TPE + +The last stage of our system is a renderer that generates photorealistic facial renderings from previous predictions, as illustrated in Fig. 2. Specifically, we design a U-Net-like renderer $G_{R}$ with TPE to generate both high-fidelity and stable videos. In our experiments, TPE is defined as + +$$ +\mathrm {T P E} _ {(t, 2 i)} = \sin \left(t * 2 ^ {i} / 1 0 0\right), \tag {14} +$$ + +$$ +\mathrm {T P E} _ {(t, 2 i + 1)} = \cos (t * 2 ^ {i} / 1 0 0). +$$ + +$i = 0,1,\ldots ,5$ is the dimension and $t$ is the frame index. Then the rendered result $t$ -frame $I_{t}$ is generated with $G_{R}$ .. + +$$ +I _ {t} = G _ {R} \left(I _ {t} ^ {c} \odot I _ {r} \odot \mathrm {T P E} (t)\right), \tag {15} +$$ + +where $I_{t}^{c}$ is the condition image at frame index $t$ . $I_{r}$ is the reference image. The detailed architecture, training, and inference details are provided in our supplementary materials. + +# 3.5. Implementation Details + +Our models are trained on PyTorch [27] using Adam optimizer with hyper-parameters $(\beta_{1},\beta_{2}) = (0.9,0.99)$ . The learning rate is set to $10^{-4}$ in all experiments. + +We train all of our models on an NVIDIA 3090 GPU. It takes about (30, 2, 6) hours in total, (200, 300, 100) epochs with bath sizes of (32, 32, 4) for our three different stages, respectively. During testing, we select all the models with minimum validation loss. We use a sliding window (window size 300, stride 150) for arbitrary long input audio. + +Table 1: Comparisons with state-of-the-art methods. † denotes our generated results with size $256 \times 256$ through a small renderer. The best results are highlighted in **bold**. The number with **underline** denotes the second-best result. + +
MethodTestset A from LSP [22]Testset B from HDTF [51]
NIQE ↓LMD-v ↓LMD ↓Sync ↑MA ↑NIQE ↓LMD-v ↓LMD ↓Sync ↑MA ↑
MakeItTalk (SIGGRAPH Asia'20 [54])7.072.302.653.070.488.181.912.233.900.53
Wav2Lip (MM'20 [29])7.311.951.815.580.647.832.081.975.780.51
Wav2Lip-GAN (MM'20 [29])7.242.111.835.470.627.772.011.985.780.51
LSP (SIGGRAPH Asia'21 [22])5.752.282.063.090.617.121.672.014.110.52
AD-NeRF (ICCV'21 [10])5.812.892.772.980.41-----
SadTalker (CVPR'23 [50])5.802.512.314.140.567.072.432.373.960.51
GeneFace (ICLR'23 [44])6.612.222.173.080.65-----
Ground Truth (reference)5.280.000.004.891.006.380.000.006.071.00
Ours †5.771.741.514.520.707.051.602.044.340.59
Ours5.551.791.504.480.696.921.591.964.160.56
+ +# 4. Experiments + +# 4.1. Experimental Setup + +Dataset pre-processing. We evaluate our method on two publicly available datasets, i.e., HDTF [51] and Video samples from LSP [22] (LSP dataset). Each video contains a high-resolution portrait with an audio track. The average video length is 1-5 minutes and we process them at 25 fps. We randomly select $80\%$ of them for training and the remaining videos for evaluation. Specifically, we get 132 videos for training and 32 videos for evaluation. Each video is cropped to keep the face at the center and then resized to $512 \times 512$ . The LSP dataset contains 5 different target sequences of 4 different subjects for training and testing. These sequences span a range of 3-5 minutes. All videos are extracted at 25 fps and the synchronized audio is sampled at $16K\mathrm{Hz}$ frequency. We split videos as $80\% / 20\%$ for training and validation. + +We detect 478 3D facial landmarks for all videos using Mediapipe*. Then we estimate the head pose $H$ for all videos using method [9]. According to these head poses, the 3D facial landmarks are projected to the canonical space through rigid transformation. We extract the 3D mouth points, and eye-related points as $P^M$ and $P^E$ for each frame. The torso points are estimated from the boundary of the shoulders, which is detected through the face parsing algorithm†. For more data pre-processing details please refer to our supplement materials. + +Evaluation metrics. We demonstrate the superiority of our method on multiple metrics that are widely involved in the talking portrait field. To evaluate the correctness of generated mouth, we use mouth landmark distance (LMD) and velocity of mouth landmark distance (LMD- $\upsilon$ ) between generated video and reference video in canonical space. In + +![](images/0271c542186ab66eee211f430b89c1a4bb6a0836b6b82ea9bf4ee33bcae07aaa.jpg) +Figure 4: Visual comparison of 5 methods. + +addition, we also calculate the Insertion-over-Union (IoU) for the overlap between the predicted mouth area and the ground truth area (MA). We use the confidence score from SyncNet (Sync) [29] to measure the audio-video synchronization. Since the result cannot be perfectly aligned with the ground-truth video, we use Natural Image Quality Evaluator (NIQE) [24] as the metric for image quality. NIQE is able to capture the naturalness of image details, it is widely used in blind image quality assessment. + +![](images/e2e78a4c0748ce01e56e335989a797f5e47305cbe8bb8499b2f6b5616eba8cc3.jpg) +Figure 5: Multimodal results with the same mouth shape. + +# 4.2. Quantitative Comparison + +We compare our method with several state-of-the-art one-shot talking portrait generation works (LSP [22], MakeItTalk [54], Wav2Lip [29], AD-NeRF [10], SadTalker [50], and GeneFace [44]). For MakeItTalk, Wav2Lip, and SadTalker, the evaluation is performed on their publicly available checkpoint directly. Since these methods only generate low-resolution results, we retrained a small portrait renderer to generate low-resolution results for a fair comparison. The rest methods are retrained on our dataset under the same condition. Note that AD-NeRF and GeneFace are NeRF-based methods that are extremely time-consuming on all videos, we only provide the numerical results on the LSP dataset. As shown in Tab. 1, the proposed method achieves the best overall video quality (lowest NIQE, 5.25) and the correctness of audio-lip synchronization (lowest LMD, LMD- $v$ , and highest MA). Our method also shows comparable performance with other fully talking-head generation methods in terms of lip-sync score. Please note that a higher sync score is not always lead to better results since it is too sensitive to the audio where unnatural lip movements may get a better score [50]. + +# 4.3. Qualitative Evaluation + +User Study. We conduct user studies with 20 attendees on 30 videos generated by ours and the other methods. The driving audio is selected from four different languages: English, Chinese, Japanese, and German. The videos are generated across 5 subjects. Each participant is asked to select the best generated talking-portrait videos based on three major aspects: lip synchronization accuracy, the naturalness of movements including head movement, eye blinking, and upper body movement, and the video quality of the generated portrait. We collect the voting results and calculate the best-voting percentage of each method. The statistics are reported in Tab. 2. Overall, users prefer our results on lip synchronization, the naturalness of portrait, and video quality, indicating the effectiveness of the proposed method. + +Qualitative comparison. Fig. 4 demonstrates the visual comparison among different methods. The results from + +LSP [22] have some warping effects without 3D consistency. Wav2Lip [29] can generate accurate mouth motions. However, their mouth areas usually have blurry boundaries and artifacts, which make the video unnatural. The results from AD-NeRF [10] have blurry boundaries of shoulders. SadTalker [50] may suffer from out of sync. GeneFace [44] has obvious artifacts on the neck region. Compared to these methods, our system generates portrait videos with overall high-quality and natural mouth movements. + +Diverse outputs. Fig. 5 shows the diverse rendered videos that are driven by the same audio. These videos have different head poses, eye-blinking, and upper bodies while sharing the same mouth structures. These results demonstrate that our MODA network is able to generate vivid and diverse talking portrait videos. + +# 4.4. Ablation Study and Performance Analysis + +We conduct ablation studies on dual-attention in MODA, FaCo-Net, and TPE in portrait renderer. + +Dual-attention module. We choose to 1) replace DualAttn with a multi-layer LSTM block [12]; 2) remove the specific attention branch and 3) remove the multimodal attention branch to evaluate the effectiveness of the dual-attention module. Numerical results on LSP test set are reported in Tab. 3. Using LSTM block cannot generate multimodal results and the diverse score (here we use the variance of the generated facial landmarks) drops to 0. When removing the specific attention branch from the dual attention block, the MODA generates the over-smoothed lip movement, which may be out of lip synchronization and has large LMD and LMD- $v$ errors. + +FaCo-Net. The FaCo-Net aims to generate natural and consistent representations for our portrait renderer. We carry out an ablation study on it by removing this stage and directly replacing the eye landmarks and mouth landmarks with facial dense landmarks. Fig. 6a shows that condition images without FaCo-Net contain incorrect connections in the lip area and lose face details, leading to low SSIM $(0.871\rightarrow 0.843)$ , PSNR $(24.77\rightarrow 21.96)$ and NIQE $(5.55\rightarrow 6.71)$ rendered images (as in Tab. 4). These results consistently prove the effectiveness of FaCo-Net. + +Temporally positional encoding. We adopt the temporal consistency metric to measure to evaluate the frame-wise consistency (TCM [37]) of the generated videos. Specifically, the TCM is defined as + +$$ +\mathrm {T C M} = \frac {1}{T} \sum_ {t} ^ {T} \exp \left(- \frac {\left| \left| O _ {t} - \operatorname {w a r p} \left(O _ {t - 1}\right) \right| \right| ^ {2}}{\left| \left| V _ {t} - \operatorname {w a r p} \left(V _ {t - 1}\right) \right| \right| ^ {2}} - 1\right), \tag {16} +$$ + +where $O_{t}$ and $V_{t}$ represent the $t^{th}$ frame in the referenced video (O) and generated video (V), respectively. $\operatorname{warp}(\cdot)$ is the warping function using the optical flow [13]. The 2-norm of a matrix $||\cdot||$ is the sum of squares of its elements. + +Table 2: User study analyses measured by best-voting percentage. Higher is better. + +
ApproachLow resolution (256 × 256)High resolution (512 × 512)
MakeItTalk [54]Wav2lip [29]SadTalker [50]OursLSP [22]AD-NeRF [10]GeneFace [44]Ours
Lip-sync accuracy15.2%30.5%16.5%37.6%24.6%7.9%19.0%48.5%
Naturalness of movement12.8%14.0%18.6%54.5%19.0%6.3%7.1%67.6%
Image quality8.3%7.2%14.3%70.0%22.8%11.1%16.7%49.7%
+ +![](images/aa523b32c9e3912c9914acebe57e5786d853fd699327d1bb6f072788a5820c1c.jpg) + +![](images/06675cee64f954c3b161bea895b7882631ff84568a81d7a916a1632c53aa4360.jpg) + +![](images/4a0fea6cb7e91ce5822cbe57d051c7fb431e2f35893e752bf42ff37f1e565f23.jpg) +(a) Effectiveness of FaCo-Net. + +![](images/e211b0474c29e01bdabbfdecb17f55409b9187ecc8087cfa493c7f235c312608.jpg) +(b) Effectiveness of TPE. +Figure 6: Ablation studies on FaCo-Net (a) and temporal positional encoding (b). + +Table 3: Ablation study on MODA. Removing dual attention or replacing it with LSTM block has negative effects. + +
MethodLMD-vLMDDiverse
replace with LSTM2.492.790
w/o multimodal attention3.012.810
w/o specific attention1.801.551.70
Final1.791.501.57
+ +Table 4: Ablation study on FaCo-Net. + +
MethodSSIM ↑PSNR ↑NIQE ↓
w/o FaCo-Net Net0.84321.966.71
Final0.87124.775.55
+ +Table 5: Ablation study on TPE. Higher is better. + +
MethodTCM ↑
Renderer w/o TPE0.63
Renderer with TPE0.71
+ +Through this equation, the generated video (V) is encouraged to be temporally consistent according to variations in the reference video (O). Fig. 6b demonstrates the comparison of video sequences with/without TPE. We find TPE can stabilize video synthesis, especially when training videos with changing backgrounds. Numerical results in Tab. 5 also show that TPE can increase TCM score. + +# 5. Discussions and Conclusions + +We present a deep learning approach for synthesizing multimodal photorealistic talking-portrait animation from audio streams. Our method can render multiple personalized talking styles with arbitrary audio. Our system contains three stages, i.e., MODA, FaCo-Net, and a high-fidelity portrait renderer with temporal guidance. The first stage generates lip motion, head motion, eye blinking, and torso motion with a unified network. This network adopts a dual-attention mechanism and is able to generate diverse talking-portrait representations with correct lip synchronization. The second stage generates fine-grained facial dense landmarks powered by generated lip motion and eye blinking. Finally, we generate the intermediate representations for our temporal-guided renderer to synthesize both high-fidelity and stable talk-portrait videos. Experimental results and user studies show the superiority of our method. Analytical experiments have also verified different parts of our system. + +Limitations and future work. While our approach achieves impressive results in a wide variety of scenarios, there still exist several limitations. Similar to most deep learning-based methods, our method cannot generalize well on unseen subjects or extremely out-of-domain audio. It may require fine-tuning the renderer for new avatars. We also looking forward to future work to find a person-invariant renderer to achieve high-quality synthesis without additional finetuning. + +# References + +[1] Iz Beltagy, Matthew E Peters, and Arman Cohan. Longformer: The long-document transformer. arXiv preprint arXiv:2004.05150, 2020. 3 +[2] Lele Chen, Guofeng Cui, Celong Liu, Zhong Li, Ziyi Kou, Yi Xu, and Chenliang Xu. Talking-head generation with rhythmic head motion. In ECCV, 2020. 1 +[3] Lele Chen, Ross K. Maddox, Zhiyao Duan, and Chenliang Xu. Hierarchical cross-modal talking face generation with dynamic pixel-wise loss. In CVPR, 2019. 1 +[4] Joon Son Chung, Andrew Senior, Oriol Vinyals, and Andrew Zisserman. Lip reading sentences in the wild. In CVPR, 2017. 1, 2 +[5] Pif Edwards, Chris Landreth, Eugene Fume, and Karan Singh. Jali: an animator-centric viseme model for expressive lip synchronization. TOG, 35(4):1-11, 2016. 2 +[6] Yingruo Fan, Zhaojiang Lin, Jun Saito, Wenping Wang, and Taku Komura. Faceformer: Speech-driven 3d facial animation with transformers. In CVPR, 2022. 1, 2, 4 +[7] Guy Gafni, Justus Thies, Michael Zollhofer, and Matthias Nießner. Dynamic neural radiance fields for monocular 4d facial avatar reconstruction. In CVPR, 2021. 1 +[8] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In NeurIPS, 2014. 1, 5 +[9] Jianzhu Guo, Xiangyu Zhu, Yang Yang, Fan Yang, Zhen Lei, and Stan Z Li. Towards fast, accurate and stable 3d dense face alignment. In ECCV, 2020. 6 +[10] Yudong Guo, Keyu Chen, Sen Liang, Yong-Jin Liu, Hujun Bao, and Juyong Zhang. Ad-nerf: Audio driven neural radiance fields for talking head synthesis. In ICCV, 2021. 2, 6, 7, 8, 12, 14 +[11] Kai Han, Yunhe Wang, Hanting Chen, Xinghao Chen, Jianyuan Guo, Zhenhua Liu, Yehui Tang, An Xiao, Chunjing Xu, Yixing Xu, et al. A survey on vision transformer. PAMI, 45(1):87-110, 2022. 3 +[12] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 9(8):1735-1780, 1997. 7 +[13] Berthold KP Horn and Brian G Schunck. Determining optical flow. Artificial intelligence, 17(1-3):185–203, 1981. 7 +[14] Xinya Ji, Hang Zhou, Kaisiyuan Wang, Qianyi Wu, Wayne Wu, Feng Xu, and Xun Cao. Eamm: One-shot emotional talking face via audio-based emotion-aware motion model. In SIGGRAPH, 2022. 2 +[15] Tero Karras, Timo Aila, Samuli Laine, Antti Herva, and Jaakko Lehtinen. Audio-driven facial animation by joint end-to-end learning of pose and emotion. TOG, 36(4):1-12, 2017. 2 +[16] Salman Khan, Muzammal Naseer, Munawar Hayat, Syed Waqas Zamir, Fahad Shahbaz Khan, and Mubarak Shah. Transformers in vision: A survey. arXiv preprint arXiv:2101.01169, 2021. 2 +[17] D. P. Kingma and M. Welling. Auto-encoding variational bayes. In ICLR, 2014. 5 + +[18] Prajwal KR, Rudrabha Mukhopadhyay, Jerin Philip, Abhishek Jha, Vinay Namboodiri, and CV Jawahar. Towards automatic face-to-face translation. In ACMMM, 2019. 1 +[19] Avisek Lahiri, Vivek Kwatra, Christian Frueh, John Lewis, and Chris Bregler. Lipsync3d: Data-efficient learning of personalized 3d talking faces from video using pose and lighting normalization. In CVPR, 2021. 2 +[20] Ming-Yu Liu, Thomas Breuel, and Jan Kautz. Unsupervised image-to-image translation networks. In NeurIPS, 2017. 3, 5 +[21] Xian Liu, Yinghao Xu, Qianyi Wu, Hang Zhou, Wayne Wu, and Bolei Zhou. Semantic-aware implicit neural audio-driven video portrait generation. In ECCV. Springer, 2022. 2 +[22] Yuanxun Lu, Jinxiang Chai, and Xun Cao. Live speech portraits: real-time photorealistic talking-head animation. TOG, 40(6):1-17, 2021. 1, 2, 3, 6, 7, 8, 11, 12, 14 +[23] Larry R Medsker and LC Jain. Recurrent neural networks. Design and Applications, 5:64-67, 2001. 3 +[24] Anish Mittal, Rajiv Soundararajan, and Alan C Bovik. Making a "completely blind" image quality analyzer. IEEE Signal processing letters, 20(3):209-212, 2012. 6 +[25] Se Jin Park, Minsu Kim, Joanna Hong, Jeongsoo Choi, and Yong Man Ro. Synctalkface: Talking face generation with precise lip-syncing via audio-lip memory. In AAAI, 2022. 2 +[26] Razvan Pascanu, Tomas Mikolov, and Yoshua Bengio. On the difficulty of training recurrent neural networks. In ICML, 2013. 3 +[27] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, et al. Pytorch: An imperative style, high-performance deep learning library. NeurlPS, 32, 2019. 5 +[28] Mathis Petrovich, Michael J Black, and Gül Varol. Action-conditioned 3d human motion synthesis with transformer vae. arXiv preprint arXiv:2104.05670, 2021. 5 +[29] KR Prajwal, Rudrabha Mukhopadhyay, Vinay P Namboodiri, and CV Jawahar. A lip sync expert is all you need for speech to lip generation in the wild. In ACMMM, 2020. 1, 2, 6, 7, 8, 12 +[30] Steffen Schneider, Alexei Baevski, Ronan Collobert, and Michael Auli. Wav2vec: Unsupervised pre-training for speech recognition. arXiv preprint arXiv:1904.05862, 2019. 3 +[31] Oliver Schreer, Roman Englert, Peter Eisert, and Ralf Tanger. Real-time vision and speech driven avatars for multimedia applications. TMM, 10(3):352-360, 2008. 2 +[32] Shuai Shen, Wenliang Zhao, Zibin Meng, Wanhua Li, Zheng Zhu, Jie Zhou, and Jiwen Lu. Difftalk: Crafting diffusion models for generalized talking head synthesis. arXiv preprint arXiv:2301.03786, 2023. 2 +[33] Aliaksandr Siarohin, Stéphane Lathuilière, Sergey Tulyakov, Elisa Ricci, and Nicu Sebe. First order motion model for image animation. NeurIPS, 32, 2019. 2 +[34] Michal Stypulkowski, Konstantinos Vougioukas, Sen He, Maciej Zięba, Stavros Petridis, and Maja Pantic. Diffused heads: Diffusion models beat gans on talking-face generation. arXiv preprint arXiv:2301.03396, 2023. 2 + +[35] Anni Tang, Tianyu He, Xu Tan, Jun Ling, Runnan Li, Sheng Zhao, Li Song, and Jiang Bian. Memories are one-to-many mapping alleviators in talking face generation. arXiv preprint arXiv:2212.05005, 2022. 2 +[36] Justus Thies, Mohamed Elgharib, Ayush Tewari, Christian Theobalt, and Matthias Nießner. Neural voice puppetry: Audio-driven facial reenactment. In ECCV, 2020. 2 +[37] S. Varghese, Y. Bayzidi, A. Bar, N. Kapoor, and T. Fingscheidt. Unsupervised temporal consistency metric for video segmentation in highly-automated driving. In CVPR Workshop, 2020. 7, 11 +[38] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In NeurIPS, 2017. 2 +[39] Kaisiyuan Wang, Qianyi Wu, Linsen Song, Zhuoqian Yang, Wayne Wu, Chen Qian, Ran He, Yu Qiao, and Chen Change Loy. Mead: A large-scale audio-visual dataset for emotional talking-face generation. In ECCV, 2020. 2 +[40] Suzhen Wang, Lincheng Li, Yu Ding, Changjie Fan, and Xin Yu. Audio2head: Audio-driven one-shot talking-head generation with natural head motion. In *IJCAI*, 2021. 2 +[41] Ting-Chun Wang, Ming-Yu Liu, Jun-Yan Zhu, Guilin Liu, Andrew Tao, Jan Kautz, and Bryan Catanzaro. Video-to-video synthesis. In NeurIPS, 2018. 3 +[42] Xinsheng Wang, Qicong Xie, Jihua Zhu, Lei Xie, et al. Anyonenet: Synchronized speech and talking head generation for arbitrary person. arXiv preprint arXiv:2108.04325, 2021. 2 +[43] Shunyu Yao, RuiZhe Zhong, Yichao Yan, Guangtao Zhai, and Xiaokang Yang. Dfa-nerf: Personalized talking head generation via disentangled face attributes neural rendering. arXiv preprint arXiv:2201.00791, 2022. 2 +[44] Zhenhui Ye, Ziyue Jiang, Yi Ren, Jinglin Liu, JinZheng He, and Zhou Zhao. Geneface: Generalized and high-fidelity audio-driven 3d talking face synthesis. In ICLR, 2023. 1, 2, 4, 6, 7, 8, 14 +[45] Ran Yi, Zipeng Ye, Juyong Zhang, Hujun Bao, and Yong-Jin Liu. Audio-driven talking face video generation with learning-based personalized head pose. arXiv preprint arXiv:2002.10137, 2020. 2 +[46] Zili Yi, Hao Zhang, Ping Tan, and Minglun Gong. Dualgan: Unsupervised dual learning for image-to-image translation. In ICCV, 2017. 3 +[47] Changqian Yu, Changxin Gao, Jingbo Wang, Gang Yu, Chunhua Shen, and Nong Sang. Bisenet v2: Bilateral network with guided aggregation for real-time semantic segmentation. IJCV, 129:3051-3068, 2021. 12 +[48] Egor Zakharov, Aliaksandra Shysheya, Egor Burkov, and Victor Lempitsky. Few-shot adversarial learning of realistic neural talking head models. In ICCV, 2019. 2 +[49] Chenxu Zhang, Yifan Zhao, Yifei Huang, Ming Zeng, Saifeng Ni, Madhukar Budagavi, and Xiaohu Guo. Facial: Synthesizing dynamic talking face with implicit attribute learning. In ICCV, 2021. 1 +[50] Wenxuan Zhang, Xiaodong Cun, Xuan Wang, Yong Zhang, Xi Shen, Yu Guo, Ying Shan, and Fei Wang. Sadtalker: Learning realistic 3d motion coefficients for stylized audio-driven single image talking face animation. In CVPR, 2023. 1, 2, 3, 6, 7, 8 + +[51] Zhimeng Zhang, Lincheng Li, Yu Ding, and Changjie Fan. Flow-guided one-shot talking face generation with a high-resolution audio-visual dataset. In CVPR, 2021. 2, 6 +[52] Hang Zhou, Yasheng Sun, Wayne Wu, Chen Change Loy, Xiaogang Wang, and Ziwei Liu. Pose-controllable talking face generation by implicitly modularized audio-visual representation. In CVPR, 2021. 1, 2 +[53] Yijun Zhou and James Gregson. Whenet: Real-time fine-grained estimation for wide range head pose. arXiv preprint arXiv:2005.10353, 2020. 11 +[54] Yang Zhou, Xintong Han, Eli Shechtman, Jose Echevarria, Evangelos Kalogerakis, and Dingzeyu Li. Makelttalk: speaker-aware talking-head animation. TOG, 39(6):1-15, 2020. 1, 2, 3, 6, 7, 8, 12 +[55] Yang Zhou, Zhan Xu, Chris Landreth, Evangelos Kalogerakis, Subhransu Maji, and Karan Singh. Visemenet: Audio-driven animator-centric speech animation. TOG, 37(4):1-10, 2018. 2 +[56] Hao Zhu, Huaibo Huang, Yi Li, Aihua Zheng, and Ran He. Arbitrary talking face generation via attentional audio-visual coherence learning. In IJCAI, 2020. 2 \ No newline at end of file diff --git a/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/images.zip b/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..3bc9308f2b54a4ffcb39291a2e78fe33dd84e808 --- /dev/null +++ b/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:b54cc4cade39e012a6af231e5129e4630ea0d9db763c89810fabbb6a0e33bfef +size 658706 diff --git a/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/layout.json b/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..2665b0886e6954fb18c711642d14c58a68874661 --- /dev/null +++ b/2023/MODA_ Mapping-Once Audio-driven Portrait Animation with Dual Attentions/layout.json @@ -0,0 +1,9751 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 53, + 103, + 541, + 122 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 103, + 541, + 122 + ], + "spans": [ + { + "bbox": [ + 53, + 103, + 541, + 122 + ], + "type": "text", + "content": "MODA: Mapping-Once Audio-driven Portrait Animation with Dual Attentions" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 111, + 141, + 481, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 141, + 481, + 185 + ], + "spans": [ + { + "bbox": [ + 111, + 141, + 481, + 185 + ], + "type": "text", + "content": "Yunfei Liu1 Lijian Lin1 Fei Yu2 Changyin Zhou2 Yu Li1* 1International Digital Economy Academy (IDEA) 2Vstring Inc. https://tinyurl.com/iccv23-modala" + } + ] + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 60, + 217, + 535, + 392 + ], + "blocks": [ + { + "bbox": [ + 60, + 217, + 535, + 392 + ], + "lines": [ + { + "bbox": [ + 60, + 217, + 535, + 392 + ], + "spans": [ + { + "bbox": [ + 60, + 217, + 535, + 392 + ], + "type": "image", + "image_path": "bbaaec040456d9d6ae7cce19783479400bdfff4903c90b1a381964923e40ffa0.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 396, + 545, + 408 + ], + "lines": [ + { + "bbox": [ + 47, + 396, + 545, + 408 + ], + "spans": [ + { + "bbox": [ + 47, + 396, + 545, + 408 + ], + "type": "text", + "content": "Figure 1: We propose a mapping-once system with dual-attention for multimodal and high-fidelity portrait video animation." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 418, + 192, + 430 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 418, + 192, + 430 + ], + "spans": [ + { + "bbox": [ + 143, + 418, + 192, + 430 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 443, + 290, + 684 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 443, + 290, + 684 + ], + "spans": [ + { + "bbox": [ + 46, + 443, + 290, + 684 + ], + "type": "text", + "content": "Audio-driven portrait animation aims to synthesize portrait videos that are conditioned by given audio. Animating high-fidelity and multimodal video portraits has a variety of applications. Previous methods have attempted to capture different motion modes and generate high-fidelity portrait videos by training different models or sampling signals from given videos. However, lacking correlation learning between lip-sync and other movements (e.g., head pose/eye blinking) usually leads to unnatural results. In this paper, we propose a unified system for multi-person, diverse, and high-fidelity talking portrait generation. Our method contains three stages, i.e., 1) Mapping-Once network with Dual Attentions (MODA) generates talking representation from given audio. In MODA, we design a dual-attention module to encode accurate mouth movements and diverse modalities. 2) Facial composer network generates dense and detailed face landmarks, and 3) temporal-guided renderer syntheses stable videos. Extensive evaluations demonstrate that the proposed system produces more natural and realistic video portraits compared to previous methods." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 307, + 418, + 386, + 430 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 418, + 386, + 430 + ], + "spans": [ + { + "bbox": [ + 307, + 418, + 386, + 430 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 438, + 545, + 593 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 438, + 545, + 593 + ], + "spans": [ + { + "bbox": [ + 304, + 438, + 545, + 593 + ], + "type": "text", + "content": "Given an input audio, talking portrait animation is to synthesize video frames of a person whose poses and expressions are synchronized with the audio signal [2, 3, 4, 18]. This audio-driven portrait video generation task has gained increasing attention recently and has a wide range of applications in digital avatars, gaming, telepresence, virtual reality (VR), video production etc. Conventional portrait video generation consumes intensive labor and time during setting up the background, make-up, lighting, shooting, and editing. Moreover, a re-shot is always required when there exists new textual content. In contrast, audio-driven talking video generation is more convenient and attractive which only requires a new audio clip to render a new video." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 594, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 546, + 713 + ], + "type": "text", + "content": "Previous methods [7, 29, 52] try to learn the correspondence between audio and frames. However, these methods usually ignore the head pose as it is hard to separate head posture from facial movement. Many 3D face reconstruction algorithm-based and GAN-based [8] methods estimate intermediate representations, such as 3D face shapes [6, 50], 2D landmarks [22, 54], or face expression parameters [49], to assist the generation process. However, such sparse representations usually lost facial details, leading to over-smooth [44]. Recently, the neural radiance field" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 702, + 135, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 135, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 135, + 712 + ], + "type": "text", + "content": "*Corresponding author." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "footer", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "23020" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 133 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 133 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 133 + ], + "type": "text", + "content": "(NeRF) [10, 44] has been widely applied in talking head generation for high-fidelity results. However, the implicit neural representation is hard to interpret and control. In addition, these methods are usually person-specific and require extra training or adaptation time for different persons." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 136, + 289, + 316 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 136, + 289, + 316 + ], + "spans": [ + { + "bbox": [ + 46, + 136, + 289, + 316 + ], + "type": "text", + "content": "Although quite a number of attempts and progresses have been made in recent years, it is still challenging to generate realistic and expressive talking videos. As humans are extremely sensitive to identifying the artifacts in the synthesized portrait videos, it sets a very high standard for this technique to become applicable. We summarize the following key points that affect human perceptions: 1) Correctness. The synthesized talking portrait video should be well synchronized with the driven audio. 2) Visual quality. The synthesized video should have high resolution and contain fine detail components. 3) Diversity. Besides the lip motion needing to be exactly matched to the audio content, the motion of other components like eye blinking and head movement are not deterministic. They should move naturally as a natural human does." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 319, + 289, + 522 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 319, + 289, + 522 + ], + "spans": [ + { + "bbox": [ + 46, + 319, + 289, + 522 + ], + "type": "text", + "content": "To achieve these goals, previous approaches either map the mouth landmarks and the head pose separately by learning different sub-networks [22, 50], or only model the mouth movement while the head pose is obtained from the existing video [29, 52]. However, lacking correlation learning between lip-sync and other movements usually leads to unnatural results. In this paper, we propose a mapping-once network with dual attentions (MODA), which is a unified architecture to generate diverse representations for a talking portrait, simplifying the computational steps. In order to combine synchronization and diversity of the talking portrait generation, we carefully design a dual-attention module to learn deterministic mappings (i.e., the accurate mouth movements driven by audio) and probabilistic sampling (i.e., the diverse head pose/eye blinking from time-to-time), respectively. To summarize, our contributions can be listed as follows:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 59, + 534, + 286, + 704 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 59, + 534, + 286, + 582 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 534, + 286, + 582 + ], + "spans": [ + { + "bbox": [ + 59, + 534, + 286, + 582 + ], + "type": "text", + "content": "- We propose a talking portrait system that generates multimodal photorealistic portrait videos with accurate lip motion. Comprehensive evaluations demonstrate our system can achieve state-of-the-art performance." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 59, + 583, + 286, + 619 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 583, + 286, + 619 + ], + "spans": [ + { + "bbox": [ + 59, + 583, + 286, + 619 + ], + "type": "text", + "content": "- We propose a unified mapping-once with dual attention (MODA) network for generating portrait representation from subject conditions and arbitrary audio." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 59, + 621, + 286, + 704 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 621, + 286, + 704 + ], + "spans": [ + { + "bbox": [ + 59, + 621, + 286, + 704 + ], + "type": "text", + "content": "- We propose 3 technical points for taking portrait generation: 1) A transformer-based dual attention module for generating both specific and diverse representations. 2) A facial composer network to get accurate and detailed facial landmarks. 3) A temporally guided renderer to synthesize videos with both high quality and temporal stabilization." + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 71, + 398, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 71, + 398, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 71, + 398, + 84 + ], + "type": "text", + "content": "2. Related Works" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 91, + 545, + 270 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 91, + 545, + 270 + ], + "spans": [ + { + "bbox": [ + 304, + 91, + 545, + 270 + ], + "type": "text", + "content": "Audio-driven portrait animation. Talking heads and facial animation are research hot-spots in the computer vision community. Extensive approaches [5, 55] explore audio-driven mouth animation and audio-driven facial animation. We focus on animating a portrait in this work. Many methods [4, 5, 29, 31, 56] aim to find the correspondence between audio and frames. A large number of technologies (such as flow-learning [14, 40, 51], memory bank [25, 35], etc.) are explored for the correctness of talking head generation. However, these methods usually ignore the head pose, torso motion, and eye blinking, which are essential for a natural talking portrait generation. To generate diverse talking heads, recent methods [19, 52] propose to embed other modalities to control emotions or head pose. However, these methods usually require additional inputs." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 270, + 546, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 270, + 546, + 521 + ], + "spans": [ + { + "bbox": [ + 304, + 270, + 546, + 521 + ], + "type": "text", + "content": "Recently, neural radiance field (NeRF) [10] has been widely applied in 3D-related tasks as it can accurately reproduce complex scenes with implicit neural representation. Several works [10, 43, 21, 44] leverage NeRF to represent faces with audio features as conditions. Despite the high-quality results achieved, the motion of generated results is usually unnatural. Besides, the learning and inference processes are time-consuming. More recently, some diffusion-based methods [32, 34] are proposed to generate talking heads. However, their speed is limited by a large number of sampling steps in the diffusion process. Some methods are based on the 3D face reconstruction and GAN [15, 22, 45]. They estimate intermediate representations such as 2D landmarks [39, 48, 54], 3D face shapes [15, 36] or facial expression parameters [42, 50], to assist the generation process. Unfortunately, such sparse representation usually lost facial details. In this paper, we propose to learn dense facial landmarks and upper body points through a unified framework for talking portrait generation. The intermediate representation contains facial details and other movements, which can be interpreted and controlled easily." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 522, + 545, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 522, + 545, + 641 + ], + "spans": [ + { + "bbox": [ + 304, + 522, + 545, + 641 + ], + "type": "text", + "content": "Transformers in audio-driven tasks. Transformer [38] is a strong alternative to both RNN and CNN. Researchers find it works well in multimodal scenarios. We refer readers to the comprehensive survey [16] for further information. Some recent works adopt transformers to generate results from different modalities, such as audio-to-text, language translation, music-to-dance, etc. The most related work is FaceFormer [6], which is a speech-driven 3D facial animation approach. They proposed two types of bias for the transformer to better align audio and 3D face animation." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": "Vision-based facial reenactment. Video-based facial reenactment is another technique related to audio-driven animation [33, 31]. There are many works to reenact faces with different techniques, such as adversarial learning, few-shot learning, or even one-shot facial animation. They usually adopt pre-defined facial landmarks or in an unsupervised" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "23021" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 55, + 68, + 547, + 168 + ], + "blocks": [ + { + "bbox": [ + 55, + 68, + 547, + 168 + ], + "lines": [ + { + "bbox": [ + 55, + 68, + 547, + 168 + ], + "spans": [ + { + "bbox": [ + 55, + 68, + 547, + 168 + ], + "type": "image", + "image_path": "e2a46c4d52521b48a864f66a273f9e15275813ec0d466a2e1f4c70456137f8b3.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 175, + 547, + 222 + ], + "lines": [ + { + "bbox": [ + 46, + 175, + 547, + 222 + ], + "spans": [ + { + "bbox": [ + 46, + 175, + 547, + 222 + ], + "type": "text", + "content": "Figure 2: The proposed method is a three-stage system. Given the subject figure and arbitrary audio, the proposed system generates audio-driven video. Here " + }, + { + "bbox": [ + 46, + 175, + 547, + 222 + ], + "type": "inline_equation", + "content": "\\mathbb{O}" + }, + { + "bbox": [ + 46, + 175, + 547, + 222 + ], + "type": "text", + "content": " denotes rigid transformation from canonical space to camera coordinate via head pose, " + }, + { + "bbox": [ + 46, + 175, + 547, + 222 + ], + "type": "inline_equation", + "content": "\\odot" + }, + { + "bbox": [ + 46, + 175, + 547, + 222 + ], + "type": "text", + "content": " denotes concatenation. " + }, + { + "bbox": [ + 46, + 175, + 547, + 222 + ], + "type": "inline_equation", + "content": "\\mathbb{P}" + }, + { + "bbox": [ + 46, + 175, + 547, + 222 + ], + "type": "text", + "content": " is projection from 3D space to image coordinate. FaCo-Net is a facial composer network, which will be introduced in Sec. 3.3." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 230, + 289, + 386 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 230, + 289, + 386 + ], + "spans": [ + { + "bbox": [ + 46, + 230, + 289, + 386 + ], + "type": "text", + "content": "scheme. In another aspect, image-to-image translation (I2I) methods [20, 46] have also demonstrated impressive performance in converting images from one domain to another. However, single-frame renderers [20] ignore the temporal relations among video frames, leading to color jitters or unnatural background shakes in the final results. [41] proposes to use RNN [23] to capture the temporal relations among the input conditions, which generates stabilized results. However, these methods have difficulties in training [26]. In this paper, we find an alternative way to embed temporal information into I2I. Simply using temporal positional embedding [11] as an input condition, our method can achieve natural and stabilized results." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 399, + 130, + 414 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 399, + 130, + 414 + ], + "spans": [ + { + "bbox": [ + 47, + 399, + 130, + 414 + ], + "type": "text", + "content": "3. Methodology" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 420, + 287, + 564 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 420, + 287, + 564 + ], + "spans": [ + { + "bbox": [ + 46, + 420, + 287, + 564 + ], + "type": "text", + "content": "We present a talking portrait system for high-fidelity portrait video generation with accurate lip motion and multimodal motions, including head pose, eye blinking, and torso movements. The overall pipeline of this system is illustrated in Fig. 2. It contains three stages, 1) given the driven audio and conditioned subjects, mapping once talking portrait network with dual attentions (MODA) generates multimodal and correct semantic portrait components, 2) in the next, the facial composer network combines the facial components together and adds details for dense facial vertices, and 3) finally, a portrait renderer with temporally positional embedding (TPE) syntheses high-fidelity and stable videos." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 574, + 141, + 586 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 574, + 141, + 586 + ], + "spans": [ + { + "bbox": [ + 47, + 574, + 141, + 586 + ], + "type": "text", + "content": "3.1. Task Definition" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": "In this section, we give the definition of the talking portrait task, which is to formulate a sequence-to-sequence translation manner [1] from talking portrait videos. Specifically, given a " + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": "-length audio sequence " + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{A} = \\{a_0, a_1, \\dots, a_T\\}" + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": " with audio sampling rate " + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": ", a talking portrait method aims to map it into the corresponding video clip " + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{V} = \\{I_0, I_1, \\dots, I_K\\}" + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": " frame-per-second (FPS), where " + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "inline_equation", + "content": "K = \\lfloor fT / r \\rfloor" + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": ". Since the data dimension of " + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{V}" + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": " is much larger than " + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{A}" + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": ", many researchers propose to generate " + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{V}" + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": " progressively and introduce many types of intermediate" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "spans": [ + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "text", + "content": "representation " + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "inline_equation", + "content": "\\mathbf{R}" + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "text", + "content": ". To make the generated " + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "inline_equation", + "content": "\\mathbf{V}" + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "text", + "content": " look natural, the constraint on " + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "inline_equation", + "content": "\\mathbf{R}" + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "text", + "content": " is critical. In previous audio-driven face animation approaches, " + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "inline_equation", + "content": "\\mathbf{R}" + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "text", + "content": " typically represents one type of face information, such as facial landmarks [22, 54] or head pose [50]. To better represent a talking portrait, we define " + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "inline_equation", + "content": "\\mathbf{R}" + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "text", + "content": " as the union of different portrait descriptors, i.e., " + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "inline_equation", + "content": "\\mathbf{R} = \\{P^M, P^E, P^F, H, P^T\\}" + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "text", + "content": ", where the elements of " + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "inline_equation", + "content": "\\mathbf{R}" + }, + { + "bbox": [ + 304, + 230, + 545, + 325 + ], + "type": "text", + "content": " are defined as follows," + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 313, + 327, + 545, + 468 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 313, + 327, + 545, + 352 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 313, + 327, + 545, + 352 + ], + "spans": [ + { + "bbox": [ + 313, + 327, + 545, + 352 + ], + "type": "text", + "content": "1. Mouth points " + }, + { + "bbox": [ + 313, + 327, + 545, + 352 + ], + "type": "inline_equation", + "content": "P^M \\in \\mathbb{R}^{40 \\times 3}" + }, + { + "bbox": [ + 313, + 327, + 545, + 352 + ], + "type": "text", + "content": ". They have 40 points for representing mouth animation." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 313, + 354, + 545, + 378 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 313, + 354, + 545, + 378 + ], + "spans": [ + { + "bbox": [ + 313, + 354, + 545, + 378 + ], + "type": "text", + "content": "2. Eyes points " + }, + { + "bbox": [ + 313, + 354, + 545, + 378 + ], + "type": "inline_equation", + "content": "P^{E} \\in \\mathbb{R}^{60 \\times 3}" + }, + { + "bbox": [ + 313, + 354, + 545, + 378 + ], + "type": "text", + "content": ". They consist of eye and eyebrow points, which control eye blinking." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 313, + 380, + 545, + 403 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 313, + 380, + 545, + 403 + ], + "spans": [ + { + "bbox": [ + 313, + 380, + 545, + 403 + ], + "type": "text", + "content": "3. Facial points " + }, + { + "bbox": [ + 313, + 380, + 545, + 403 + ], + "type": "inline_equation", + "content": "P^{F} \\in \\mathbb{R}^{478 \\times 3}" + }, + { + "bbox": [ + 313, + 380, + 545, + 403 + ], + "type": "text", + "content": ". They contain dense facial 3D points for recording expression details." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 313, + 406, + 545, + 442 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 313, + 406, + 545, + 442 + ], + "spans": [ + { + "bbox": [ + 313, + 406, + 545, + 442 + ], + "type": "text", + "content": "4. Head pose " + }, + { + "bbox": [ + 313, + 406, + 545, + 442 + ], + "type": "inline_equation", + "content": "H \\in \\mathbb{R}^6" + }, + { + "bbox": [ + 313, + 406, + 545, + 442 + ], + "type": "text", + "content": ". It contains head rotations " + }, + { + "bbox": [ + 313, + 406, + 545, + 442 + ], + "type": "inline_equation", + "content": "(\\theta, \\phi, \\psi)" + }, + { + "bbox": [ + 313, + 406, + 545, + 442 + ], + "type": "text", + "content": " in Euler angle and head transposes " + }, + { + "bbox": [ + 313, + 406, + 545, + 442 + ], + "type": "inline_equation", + "content": "(x, y, z)" + }, + { + "bbox": [ + 313, + 406, + 545, + 442 + ], + "type": "text", + "content": " in Euclidean space)." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 313, + 443, + 545, + 468 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 313, + 443, + 545, + 468 + ], + "spans": [ + { + "bbox": [ + 313, + 443, + 545, + 468 + ], + "type": "text", + "content": "5. Torso points " + }, + { + "bbox": [ + 313, + 443, + 545, + 468 + ], + "type": "inline_equation", + "content": "P^T \\in \\mathbb{R}^{18 \\times 3}" + }, + { + "bbox": [ + 313, + 443, + 545, + 468 + ], + "type": "text", + "content": ". They contain 18 points and each side of the shoulder is described by 9 points." + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 304, + 470, + 545, + 531 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 470, + 545, + 531 + ], + "spans": [ + { + "bbox": [ + 304, + 470, + 545, + 531 + ], + "type": "text", + "content": "Note that " + }, + { + "bbox": [ + 304, + 470, + 545, + 531 + ], + "type": "inline_equation", + "content": "P^M, P^E" + }, + { + "bbox": [ + 304, + 470, + 545, + 531 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 470, + 545, + 531 + ], + "type": "inline_equation", + "content": "P^F" + }, + { + "bbox": [ + 304, + 470, + 545, + 531 + ], + "type": "text", + "content": " are in canonical space for the convenience of face alignment. The process of talking portrait can be rewritten as " + }, + { + "bbox": [ + 304, + 470, + 545, + 531 + ], + "type": "inline_equation", + "content": "\\mathbf{A} \\rightarrow \\mathbf{R} \\rightarrow \\mathbf{V}" + }, + { + "bbox": [ + 304, + 470, + 545, + 531 + ], + "type": "text", + "content": ". We design corresponding networks for these stages, respectively. The details are provided in the following subsections." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 539, + 542, + 552 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 539, + 542, + 552 + ], + "spans": [ + { + "bbox": [ + 305, + 539, + 542, + 552 + ], + "type": "text", + "content": "3.2. Mapping-Once Network with Dual Attentions" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 558, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 545, + 712 + ], + "type": "text", + "content": "Mapping-once architecture. Given the driven audio A and subject condition S, MODA aims to map them into R (consists of lip movement, eye blinking, head pose, and torso) with a single forward process. As illustrated in Fig. 3, the network in the first step contains three parts, i.e., 1) two encoders for encoding audio features and extracting subject style, respectively, 2) a dual-attention module for generating diverse but accurate motion features, and 3) four tails for different motion synthesis. We first extract contextual features of the audio signal by Wav2Vec [30]. In the next, the extracted feature is projected into " + }, + { + "bbox": [ + 304, + 558, + 545, + 712 + ], + "type": "inline_equation", + "content": "s_a \\in \\mathbb{R}^{d \\times T}" + }, + { + "bbox": [ + 304, + 558, + 545, + 712 + ], + "type": "text", + "content": " via a multilayer perceptron (MLP), where " + }, + { + "bbox": [ + 304, + 558, + 545, + 712 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 304, + 558, + 545, + 712 + ], + "type": "text", + "content": " is the feature dimension for one frame and " + }, + { + "bbox": [ + 304, + 558, + 545, + 712 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 304, + 558, + 545, + 712 + ], + "type": "text", + "content": " denotes the number of frames of the" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "footer", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "23022" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 69, + 545, + 223 + ], + "blocks": [ + { + "bbox": [ + 51, + 69, + 545, + 223 + ], + "lines": [ + { + "bbox": [ + 51, + 69, + 545, + 223 + ], + "spans": [ + { + "bbox": [ + 51, + 69, + 545, + 223 + ], + "type": "image", + "image_path": "6e31bd9ac8c9ffa51adb6cba4928567840ea8f60b69124b2059dcbb9e3f596ee.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 231, + 547, + 257 + ], + "lines": [ + { + "bbox": [ + 46, + 231, + 547, + 257 + ], + "spans": [ + { + "bbox": [ + 46, + 231, + 547, + 257 + ], + "type": "text", + "content": "Figure 3: Architecture of MODA network. Given an audio and subject condition, MODA generates four types of motions within a single forward process. " + }, + { + "bbox": [ + 46, + 231, + 547, + 257 + ], + "type": "inline_equation", + "content": "\\oplus" + }, + { + "bbox": [ + 46, + 231, + 547, + 257 + ], + "type": "text", + "content": " denotes element-wise addition and " + }, + { + "bbox": [ + 46, + 231, + 547, + 257 + ], + "type": "inline_equation", + "content": "\\odot" + }, + { + "bbox": [ + 46, + 231, + 547, + 257 + ], + "type": "text", + "content": " is concatenation." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 265, + 288, + 326 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 265, + 288, + 326 + ], + "spans": [ + { + "bbox": [ + 46, + 265, + 288, + 326 + ], + "type": "text", + "content": "generated video. To model different speaker styles, we take the facial vertices of the conditioned subject as input. Then those vertices are projected to a " + }, + { + "bbox": [ + 46, + 265, + 288, + 326 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 265, + 288, + 326 + ], + "type": "text", + "content": "-dimensional vector " + }, + { + "bbox": [ + 46, + 265, + 288, + 326 + ], + "type": "inline_equation", + "content": "v_{s}" + }, + { + "bbox": [ + 46, + 265, + 288, + 326 + ], + "type": "text", + "content": " as the subject style code. Here the embedding layer is implemented by MLP. Next, " + }, + { + "bbox": [ + 46, + 265, + 288, + 326 + ], + "type": "inline_equation", + "content": "s_a" + }, + { + "bbox": [ + 46, + 265, + 288, + 326 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 265, + 288, + 326 + ], + "type": "inline_equation", + "content": "v_{s}" + }, + { + "bbox": [ + 46, + 265, + 288, + 326 + ], + "type": "text", + "content": " are combined as:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 129, + 338, + 287, + 352 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 129, + 338, + 287, + 352 + ], + "spans": [ + { + "bbox": [ + 129, + 338, + 287, + 352 + ], + "type": "interline_equation", + "content": "s = s _ {a} \\oplus \\operatorname {t i l e} \\left(v _ {s}\\right), \\tag {1}", + "image_path": "4d1dcf4ad2cb7666fe441a93e8773533c7da46df9499770748b628b26273a077.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "spans": [ + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "type": "text", + "content": " is the combined feature, " + }, + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "type": "inline_equation", + "content": "\\oplus" + }, + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "type": "text", + "content": " is dimension-wise addition. Then the dual-attention module (DualAttn) takes " + }, + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "type": "inline_equation", + "content": "s_a" + }, + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "type": "text", + "content": " as input, and yields a temporally contextual version " + }, + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "type": "inline_equation", + "content": "s_t" + }, + { + "bbox": [ + 47, + 357, + 287, + 394 + ], + "type": "text", + "content": "," + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 121, + 405, + 287, + 418 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 121, + 405, + 287, + 418 + ], + "spans": [ + { + "bbox": [ + 121, + 405, + 287, + 418 + ], + "type": "interline_equation", + "content": "s _ {t} = \\operatorname {D u a l A t t n} (s, s _ {a}). \\tag {2}", + "image_path": "c6427e38ecbfed92c91bf612a6ddccecf8db4387f58da8532c5767bad000e9d2.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "spans": [ + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "type": "text", + "content": "Next, we adopt 4 MLPs to decode the movements of lips " + }, + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "type": "inline_equation", + "content": "P^{M}" + }, + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "type": "text", + "content": ", head pose " + }, + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "type": "inline_equation", + "content": "H" + }, + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "type": "text", + "content": ", eye blinking " + }, + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "type": "inline_equation", + "content": "P^{E}" + }, + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "type": "text", + "content": ", and torso " + }, + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "type": "inline_equation", + "content": "P^{S}" + }, + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "type": "text", + "content": ", respectively. For each downstream task " + }, + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "type": "inline_equation", + "content": "X" + }, + { + "bbox": [ + 47, + 427, + 287, + 475 + ], + "type": "text", + "content": ", the computational process can be formulated as follows," + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 133, + 485, + 287, + 499 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 133, + 485, + 287, + 499 + ], + "spans": [ + { + "bbox": [ + 133, + 485, + 287, + 499 + ], + "type": "interline_equation", + "content": "\\Delta X = \\Phi^ {X} \\left(s _ {t}\\right), \\tag {3}", + "image_path": "30ce0fc366608d85c83b5aa2ac6041e3770e6da6cd94b0f65e00c4a7e244d232.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 508, + 287, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 508, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 46, + 508, + 287, + 533 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 508, + 287, + 533 + ], + "type": "inline_equation", + "content": "\\Phi (\\cdot)" + }, + { + "bbox": [ + 46, + 508, + 287, + 533 + ], + "type": "text", + "content": " denotes an MLP and " + }, + { + "bbox": [ + 46, + 508, + 287, + 533 + ], + "type": "inline_equation", + "content": "\\Delta X = X - \\overline{X}" + }, + { + "bbox": [ + 46, + 508, + 287, + 533 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 508, + 287, + 533 + ], + "type": "inline_equation", + "content": "\\overline{X}" + }, + { + "bbox": [ + 46, + 508, + 287, + 533 + ], + "type": "text", + "content": " is extracted from referred subject image." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 533, + 287, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 533, + 287, + 687 + ], + "spans": [ + { + "bbox": [ + 46, + 533, + 287, + 687 + ], + "type": "text", + "content": "Dual-attention module. The talking portrait generation task is highly ill-posed since it requires generating multimodal results from limited-driven information. To solve this, we propose a dual-attention module that disentangles this task into a specific mapping and a probabilistic mapping problem. Specifically, this module generates 1) the temporally aligned feature for specific mapping between audio and lip movements, as well as 2) the temporally correlated feature for probabilistic mapping between audio and other movements of the talking portrait. To this end, we first design two sub-modules to learn these two different features, respectively. Then we fuse these two features via time-wise concatenation." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 689, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 288, + 714 + ], + "type": "text", + "content": "In detail, we propose a specific attention branch (SpecAttn) to capture the temporally aligned attention" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 265, + 545, + 289 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 265, + 545, + 289 + ], + "spans": [ + { + "bbox": [ + 305, + 265, + 545, + 289 + ], + "type": "inline_equation", + "content": "s_{sa}" + }, + { + "bbox": [ + 305, + 265, + 545, + 289 + ], + "type": "text", + "content": " between " + }, + { + "bbox": [ + 305, + 265, + 545, + 289 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 305, + 265, + 545, + 289 + ], + "type": "text", + "content": " and audio feature " + }, + { + "bbox": [ + 305, + 265, + 545, + 289 + ], + "type": "inline_equation", + "content": "s_a" + }, + { + "bbox": [ + 305, + 265, + 545, + 289 + ], + "type": "text", + "content": ". Inspired by FaceFormer [6], our SpecAttn is formulated as:" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 347, + 297, + 545, + 340 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 347, + 297, + 545, + 340 + ], + "spans": [ + { + "bbox": [ + 347, + 297, + 545, + 340 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} s _ {s a} = \\operatorname {S p e c A t t n} \\left(s _ {a}, s\\right) \\\\ = \\operatorname {s o f t m a x} \\left(\\frac {\\Gamma (s) \\cdot s _ {a} ^ {T}}{\\sqrt {d}} + M _ {A}\\right) \\Gamma (s), \\tag {4} \\\\ \\end{array}", + "image_path": "422e0130134b4e7fa1d372b804a04d7d589ee6bcad6c6fd67ca8f744aff2cf5e.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 347, + 545, + 384 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 347, + 545, + 384 + ], + "spans": [ + { + "bbox": [ + 305, + 347, + 545, + 384 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 347, + 545, + 384 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 305, + 347, + 545, + 384 + ], + "type": "text", + "content": " is the dimension of " + }, + { + "bbox": [ + 305, + 347, + 545, + 384 + ], + "type": "inline_equation", + "content": "s_a, \\{\\cdot\\}^T" + }, + { + "bbox": [ + 305, + 347, + 545, + 384 + ], + "type": "text", + "content": " indicates the transpose of the input parameter. The alignment bias " + }, + { + "bbox": [ + 305, + 347, + 545, + 384 + ], + "type": "inline_equation", + "content": "M_A(1 \\leq i \\leq T, 1 \\leq j \\leq T)" + }, + { + "bbox": [ + 305, + 347, + 545, + 384 + ], + "type": "text", + "content": " is represented as:" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 353, + 392, + 545, + 419 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 353, + 392, + 545, + 419 + ], + "spans": [ + { + "bbox": [ + 353, + 392, + 545, + 419 + ], + "type": "interline_equation", + "content": "M _ {A} (i, j) = \\left\\{ \\begin{array}{l l} 0, & i = j \\\\ - \\infty , & \\text {o t h e r w i s e .} \\end{array} \\right. \\tag {5}", + "image_path": "21e2637f45a7c657091167a3c41d262e906d857414f9fad39739f4fdb03fa710.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 426, + 545, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 426, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 305, + 426, + 545, + 498 + ], + "type": "text", + "content": "Different from FaceFormer which performs cross-attention in an auto-regressive manner, we apply this operation on the entire sequence, which boosts the computation speed " + }, + { + "bbox": [ + 305, + 426, + 545, + 498 + ], + "type": "inline_equation", + "content": "T \\times" + }, + { + "bbox": [ + 305, + 426, + 545, + 498 + ], + "type": "text", + "content": " faster. In addition, to capture rich temporal information, we adopt a periodic positional encoding (PPE) and a biased casual self-attention on " + }, + { + "bbox": [ + 305, + 426, + 545, + 498 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 305, + 426, + 545, + 498 + ], + "type": "text", + "content": " (as in [6]):" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 309, + 504, + 545, + 541 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 504, + 545, + 541 + ], + "spans": [ + { + "bbox": [ + 309, + 504, + 545, + 541 + ], + "type": "interline_equation", + "content": "s ^ {\\prime} = \\Gamma (s) = \\operatorname {s o f t m a x} \\left(\\frac {\\mathrm {P P E} (s) \\cdot \\mathrm {P P E} (s) ^ {T}}{\\sqrt {d}} + M _ {T}\\right) \\mathrm {P P E} (s). \\tag {6}", + "image_path": "7ad71cb707f9255014c8c4799a9c56a4ab7aa02582c49f650787c4b45e74f9bf.jpg" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 305, + 541, + 545, + 578 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 541, + 545, + 578 + ], + "spans": [ + { + "bbox": [ + 305, + 541, + 545, + 578 + ], + "type": "inline_equation", + "content": "M_T" + }, + { + "bbox": [ + 305, + 541, + 545, + 578 + ], + "type": "text", + "content": " is a matrix that has negative infinity in the upper triangle to avoid looking at future frames to make current predictions. " + }, + { + "bbox": [ + 305, + 541, + 545, + 578 + ], + "type": "inline_equation", + "content": "M_T" + }, + { + "bbox": [ + 305, + 541, + 545, + 578 + ], + "type": "text", + "content": " is defined as:" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 342, + 584, + 545, + 611 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 342, + 584, + 545, + 611 + ], + "spans": [ + { + "bbox": [ + 342, + 584, + 545, + 611 + ], + "type": "interline_equation", + "content": "M _ {T} (i, j) = \\left\\{ \\begin{array}{l l} \\lfloor (i - j) q \\rfloor , & j \\leq i, \\\\ - \\infty , & \\text {o t h e r w i s e}, \\end{array} \\right. \\tag {7}", + "image_path": "4b1d1738784c6483948fc736f007c3eeea4edb524b924e404988e056fe1a00c6.jpg" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 618, + 545, + 666 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 618, + 545, + 666 + ], + "spans": [ + { + "bbox": [ + 304, + 618, + 545, + 666 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 618, + 545, + 666 + ], + "type": "inline_equation", + "content": "q" + }, + { + "bbox": [ + 304, + 618, + 545, + 666 + ], + "type": "text", + "content": " is a hyper-parameter for tuning the sequence period. By doing this, the encoded feature " + }, + { + "bbox": [ + 304, + 618, + 545, + 666 + ], + "type": "inline_equation", + "content": "s'" + }, + { + "bbox": [ + 304, + 618, + 545, + 666 + ], + "type": "text", + "content": " contains rich spatial-temporal information, which aids the accurate talking portrait generation." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 666, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 666, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 666, + 545, + 714 + ], + "type": "text", + "content": "To generate vivid results and avoid the oversmoothing [44] representations, it is essential to learn the probabilistic mapping between the audio feature and portrait motions. We notice that Variational Autoencoder" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "footer", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "23023" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "content": "(VAE) [17] can model probabilistic synthesis and shows many advanced performances in sequence generation tasks. Therefore, based on an advanced transformer Variational Autoencoder (t-VAE) [28], we design a probabilistic attention branch to generate diverse results. Formally, given the representation " + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "content": ", the probabilistic attention (ProbAttn) aims to generate a diverse feature " + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "inline_equation", + "content": "s_{pa}" + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "content": ". It first models the distribution of " + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "content": " with learned " + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "inline_equation", + "content": "\\mu" + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "content": " through an encoder (Enc). Then it generates multimodal outputs through a re-sample operation with a decoder (Dec). The computational process is" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 86, + 212, + 287, + 231 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 86, + 212, + 287, + 231 + ], + "spans": [ + { + "bbox": [ + 86, + 212, + 287, + 231 + ], + "type": "interline_equation", + "content": "\\mu , \\log \\sigma = \\Phi^ {\\mu} (\\operatorname {E n c} (s)), \\Phi^ {\\sigma} (\\operatorname {E n c} (s)), \\tag {8}", + "image_path": "e566fc366581ed45f62f8c06c902e21042da3391ed7980b0e7199f943aa4a1f7.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 106, + 228, + 246, + 240 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 106, + 228, + 246, + 240 + ], + "spans": [ + { + "bbox": [ + 106, + 228, + 246, + 240 + ], + "type": "interline_equation", + "content": "s _ {p a} = \\operatorname {D e c} (x), \\text {s . t .} x \\sim \\mathcal {U} (\\mu , \\sigma),", + "image_path": "a0ae2fc25fe4c658e7953afbe1e5669f4ddb145f18c4e83b1c31329b266276e6.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 248, + 288, + 308 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 248, + 288, + 308 + ], + "spans": [ + { + "bbox": [ + 47, + 248, + 288, + 308 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 248, + 288, + 308 + ], + "type": "inline_equation", + "content": "\\Phi" + }, + { + "bbox": [ + 47, + 248, + 288, + 308 + ], + "type": "text", + "content": " is an MLP. " + }, + { + "bbox": [ + 47, + 248, + 288, + 308 + ], + "type": "inline_equation", + "content": "\\mathcal{U}(\\mu, \\sigma)" + }, + { + "bbox": [ + 47, + 248, + 288, + 308 + ], + "type": "text", + "content": " is the Gaussian distribution with mean " + }, + { + "bbox": [ + 47, + 248, + 288, + 308 + ], + "type": "inline_equation", + "content": "\\mu" + }, + { + "bbox": [ + 47, + 248, + 288, + 308 + ], + "type": "text", + "content": " and variance " + }, + { + "bbox": [ + 47, + 248, + 288, + 308 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 47, + 248, + 288, + 308 + ], + "type": "text", + "content": ". To force ProbAttn to learn diverse motion styles, we add Kullback-Leibler divergence (KLD) loss to constrain the feature from the bottleneck of t-VAE. The KLD loss is defined as follows:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 79, + 315, + 287, + 343 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 79, + 315, + 287, + 343 + ], + "spans": [ + { + "bbox": [ + 79, + 315, + 287, + 343 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {K L D} = \\left(- \\frac {1}{2 d _ {l}} \\sum^ {d _ {l}} (\\log \\sigma - \\mu^ {2} - \\sigma + 1), \\right. \\tag {9}", + "image_path": "cb01f6c58b0f54d53767098142adffeda2e33d47634da1290523ebd311943726.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 350, + 287, + 374 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 350, + 287, + 374 + ], + "spans": [ + { + "bbox": [ + 47, + 350, + 287, + 374 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 350, + 287, + 374 + ], + "type": "inline_equation", + "content": "d_{l}" + }, + { + "bbox": [ + 47, + 350, + 287, + 374 + ], + "type": "text", + "content": " is the dimension of " + }, + { + "bbox": [ + 47, + 350, + 287, + 374 + ], + "type": "inline_equation", + "content": "\\mu" + }, + { + "bbox": [ + 47, + 350, + 287, + 374 + ], + "type": "text", + "content": ". Finally, the dual-attention module outputs " + }, + { + "bbox": [ + 47, + 350, + 287, + 374 + ], + "type": "inline_equation", + "content": "s_{t} = s_{sa} \\odot s_{pa}" + }, + { + "bbox": [ + 47, + 350, + 287, + 374 + ], + "type": "text", + "content": " for downstream tasks." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 374, + 287, + 456 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 374, + 287, + 456 + ], + "spans": [ + { + "bbox": [ + 47, + 374, + 287, + 456 + ], + "type": "text", + "content": "Loss functions. The MODA has four decoders for generating talking portrait-related motions. To learn the mapping from the dual-attention module and four different types of motion, we adopt a multi-task learning scheme for MODA. Specifically, we minimize the " + }, + { + "bbox": [ + 47, + 374, + 287, + 456 + ], + "type": "inline_equation", + "content": "L_{1}" + }, + { + "bbox": [ + 47, + 374, + 287, + 456 + ], + "type": "text", + "content": " distance between the ground-truth displacements and the predicted displacements. The loss can be written as" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 61, + 463, + 287, + 495 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 463, + 287, + 495 + ], + "spans": [ + { + "bbox": [ + 61, + 463, + 287, + 495 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {L} _ {T P} = \\lambda_ {1} \\left| \\Delta P _ {g t} ^ {M} - \\Delta P ^ {M} \\right| + \\lambda_ {2} \\left| \\Delta R _ {g t} - \\Delta R \\right| \\tag {10} \\\\ + \\lambda_ {3} | \\Delta P _ {g t} ^ {E} - \\Delta P ^ {E} | + \\lambda_ {4} | \\Delta P _ {g t} ^ {S} - \\Delta P ^ {S} |, \\\\ \\end{array}", + "image_path": "50d7d3841fa3011f4cfa77b2fbb9d0f194e9f87bd33e5c0adc52c23b06d68d58.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "spans": [ + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "inline_equation", + "content": "\\lambda_1, \\lambda_2, \\lambda_3, \\lambda_4" + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "text", + "content": " are hyper-parameters for balancing the different weights of downstream tasks. " + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "inline_equation", + "content": "|\\cdot|" + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "text", + "content": " is the " + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "inline_equation", + "content": "L_{1}" + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "text", + "content": "-norm. " + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "inline_equation", + "content": "\\Delta P_{gt}^{*}" + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "inline_equation", + "content": "\\Delta P^{*}" + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "text", + "content": " indicate the displacements of the ground truth and the predicted result, respectively. The total loss function is the sum of " + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{TP}" + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{KLD}" + }, + { + "bbox": [ + 47, + 502, + 287, + 562 + ], + "type": "text", + "content": ", i.e.," + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 116, + 571, + 287, + 583 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 116, + 571, + 287, + 583 + ], + "spans": [ + { + "bbox": [ + 116, + 571, + 287, + 583 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {T P} + \\mathcal {L} _ {K L D}. \\tag {11}", + "image_path": "b7e0c7ae1008a5d73310c88c4832de87a7bb9c980e20258168c4eaad10b722c7.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 599, + 192, + 612 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 599, + 192, + 612 + ], + "spans": [ + { + "bbox": [ + 47, + 599, + 192, + 612 + ], + "type": "text", + "content": "3.3. FacialComposerNetwork" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "text", + "content": "Given the subject information " + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{S}" + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "text", + "content": ", the generated mouth points " + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "inline_equation", + "content": "P^{M}" + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "text", + "content": ", and eye points " + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "inline_equation", + "content": "P^{E}" + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "text", + "content": ", the facial composer network (FaCo-Net) aims to compose the refined facial dense landmarks. The generated facial dense landmarks " + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "inline_equation", + "content": "P^{F} = \\mathrm{FaCo - Net}(\\mathbf{S}, P^{M}, P^{E})" + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "text", + "content": ". FaCo-Net consists of three encoders for consuming those three inputs and a decoder for facial landmarks generation. Similar to MODA, the subject encoder projects facial points " + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{S}" + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "text", + "content": " into a style code " + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\pmb{p}_{f}" + }, + { + "bbox": [ + 47, + 618, + 287, + 713 + ], + "type": "text", + "content": ". The" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "inline_equation", + "content": "P^{M}" + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "inline_equation", + "content": "P^{E}" + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "text", + "content": " are also projected to " + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "inline_equation", + "content": "\\pmb{p}_{m}" + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "inline_equation", + "content": "\\pmb{p}_{e}" + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "text", + "content": ", which share the same latent space as " + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "inline_equation", + "content": "\\pmb{p}_{f}" + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "text", + "content": ". Next, " + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "inline_equation", + "content": "P^{F} = \\Psi_{c}((\\pmb{p}_{m} \\odot \\pmb{p}_{e}) \\oplus \\pmb{p}_{f})" + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "inline_equation", + "content": "\\Psi_{c}" + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "text", + "content": " is a facial dense point decoder. We adopt a vanilla GAN architecture [8] as the backbone of the discriminator " + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "inline_equation", + "content": "(D)" + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "text", + "content": ". The FaCo-Net is trained to generate \"realistic\" facial dense points to fool " + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "text", + "content": ", whereas " + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 305, + 72, + 545, + 192 + ], + "type": "text", + "content": " is trained to distinguish the generated facial points from ground truths. The detailed architectures can be found in the supplementary materials. We use LSGAN loss [20] as the adversarial loss to optimize the D:" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 367, + 198, + 545, + 212 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 367, + 198, + 545, + 212 + ], + "spans": [ + { + "bbox": [ + 367, + 198, + 545, + 212 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {D i s c}} (D) = (z - 1) ^ {2} + \\hat {z} ^ {2}, \\tag {12}", + "image_path": "dd565f3aa1bf2ae98a961af09da2c374094fe5ab697b64ace47d0340361e32b1.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 219, + 545, + 255 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 219, + 545, + 255 + ], + "spans": [ + { + "bbox": [ + 305, + 219, + 545, + 255 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 219, + 545, + 255 + ], + "type": "inline_equation", + "content": "z, \\hat{z}" + }, + { + "bbox": [ + 305, + 219, + 545, + 255 + ], + "type": "text", + "content": " is the discriminator output when inputting the ground-truth face points " + }, + { + "bbox": [ + 305, + 219, + 545, + 255 + ], + "type": "inline_equation", + "content": "P_{gt}^{F}" + }, + { + "bbox": [ + 305, + 219, + 545, + 255 + ], + "type": "text", + "content": " and the generated " + }, + { + "bbox": [ + 305, + 219, + 545, + 255 + ], + "type": "inline_equation", + "content": "P^{F}" + }, + { + "bbox": [ + 305, + 219, + 545, + 255 + ], + "type": "text", + "content": ", respectively. The loss for the generator is" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 340, + 261, + 545, + 276 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 340, + 261, + 545, + 276 + ], + "spans": [ + { + "bbox": [ + 340, + 261, + 545, + 276 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {G} = \\mathcal {L} _ {G A N} (\\text {F a C o - N e t}) + \\lambda \\left| P _ {g t} ^ {F} - P ^ {F} \\right|, \\tag {13}", + "image_path": "4247daccaf4a23b9d9135096d7ea00cf48196fde35a6787999a659cecd8a5425.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "spans": [ + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "inline_equation", + "content": "P_{gt}^{F}" + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "text", + "content": " is the ground-truth dense face landmarks. " + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{GAN}(\\mathrm{FaCo - Net}) = (\\hat{z} -1)^2" + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "text", + "content": " is the adversarial loss, where " + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "inline_equation", + "content": "\\hat{z} = D(P^F)" + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "text", + "content": ". The weight " + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "text", + "content": " is empirically set to 10. After composition, the facial landmarks " + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "inline_equation", + "content": "P^{F}" + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "text", + "content": " are transformed to the camera coordinate via head pose " + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "inline_equation", + "content": "H" + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "text", + "content": ". The transformed facial landmarks and torso points " + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "inline_equation", + "content": "P^T" + }, + { + "bbox": [ + 305, + 282, + 545, + 367 + ], + "type": "text", + "content": " are projected into image space for photorealistic rendering." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 373, + 492, + 385 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 373, + 492, + 385 + ], + "spans": [ + { + "bbox": [ + 306, + 373, + 492, + 385 + ], + "type": "text", + "content": "3.4. Portrait Image Synthesis with TPE" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 392, + 545, + 451 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 392, + 545, + 451 + ], + "spans": [ + { + "bbox": [ + 305, + 392, + 545, + 451 + ], + "type": "text", + "content": "The last stage of our system is a renderer that generates photorealistic facial renderings from previous predictions, as illustrated in Fig. 2. Specifically, we design a U-Net-like renderer " + }, + { + "bbox": [ + 305, + 392, + 545, + 451 + ], + "type": "inline_equation", + "content": "G_{R}" + }, + { + "bbox": [ + 305, + 392, + 545, + 451 + ], + "type": "text", + "content": " with TPE to generate both high-fidelity and stable videos. In our experiments, TPE is defined as" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 372, + 458, + 545, + 478 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 372, + 458, + 545, + 478 + ], + "spans": [ + { + "bbox": [ + 372, + 458, + 545, + 478 + ], + "type": "interline_equation", + "content": "\\mathrm {T P E} _ {(t, 2 i)} = \\sin \\left(t * 2 ^ {i} / 1 0 0\\right), \\tag {14}", + "image_path": "fbd82b432877805e1519c6968d5d1f6c37396e680b0c5e14a0a555c94b77e264.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 362, + 475, + 489, + 488 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 362, + 475, + 489, + 488 + ], + "spans": [ + { + "bbox": [ + 362, + 475, + 489, + 488 + ], + "type": "interline_equation", + "content": "\\mathrm {T P E} _ {(t, 2 i + 1)} = \\cos (t * 2 ^ {i} / 1 0 0).", + "image_path": "24c8b430a834b3397b27fbd29cd4ca17a158a2ce03e1490758dd3fa1b5352701.jpg" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 306, + 494, + 544, + 518 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 494, + 544, + 518 + ], + "spans": [ + { + "bbox": [ + 306, + 494, + 544, + 518 + ], + "type": "inline_equation", + "content": "i = 0,1,\\ldots ,5" + }, + { + "bbox": [ + 306, + 494, + 544, + 518 + ], + "type": "text", + "content": " is the dimension and " + }, + { + "bbox": [ + 306, + 494, + 544, + 518 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 306, + 494, + 544, + 518 + ], + "type": "text", + "content": " is the frame index. Then the rendered result " + }, + { + "bbox": [ + 306, + 494, + 544, + 518 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 306, + 494, + 544, + 518 + ], + "type": "text", + "content": " -frame " + }, + { + "bbox": [ + 306, + 494, + 544, + 518 + ], + "type": "inline_equation", + "content": "I_{t}" + }, + { + "bbox": [ + 306, + 494, + 544, + 518 + ], + "type": "text", + "content": " is generated with " + }, + { + "bbox": [ + 306, + 494, + 544, + 518 + ], + "type": "inline_equation", + "content": "G_{R}" + }, + { + "bbox": [ + 306, + 494, + 544, + 518 + ], + "type": "text", + "content": " .." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 365, + 525, + 545, + 538 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 365, + 525, + 545, + 538 + ], + "spans": [ + { + "bbox": [ + 365, + 525, + 545, + 538 + ], + "type": "interline_equation", + "content": "I _ {t} = G _ {R} \\left(I _ {t} ^ {c} \\odot I _ {r} \\odot \\mathrm {T P E} (t)\\right), \\tag {15}", + "image_path": "2568ef8107613cc34f98d57d2f699f39019b1c0be9f6ae9b46f96e756dfd1c00.jpg" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 305, + 544, + 545, + 582 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 544, + 545, + 582 + ], + "spans": [ + { + "bbox": [ + 305, + 544, + 545, + 582 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 544, + 545, + 582 + ], + "type": "inline_equation", + "content": "I_{t}^{c}" + }, + { + "bbox": [ + 305, + 544, + 545, + 582 + ], + "type": "text", + "content": " is the condition image at frame index " + }, + { + "bbox": [ + 305, + 544, + 545, + 582 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 305, + 544, + 545, + 582 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 305, + 544, + 545, + 582 + ], + "type": "inline_equation", + "content": "I_{r}" + }, + { + "bbox": [ + 305, + 544, + 545, + 582 + ], + "type": "text", + "content": " is the reference image. The detailed architecture, training, and inference details are provided in our supplementary materials." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 306, + 587, + 438, + 600 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 587, + 438, + 600 + ], + "spans": [ + { + "bbox": [ + 306, + 587, + 438, + 600 + ], + "type": "text", + "content": "3.5. Implementation Details" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 305, + 605, + 545, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 605, + 545, + 641 + ], + "spans": [ + { + "bbox": [ + 305, + 605, + 545, + 641 + ], + "type": "text", + "content": "Our models are trained on PyTorch [27] using Adam optimizer with hyper-parameters " + }, + { + "bbox": [ + 305, + 605, + 545, + 641 + ], + "type": "inline_equation", + "content": "(\\beta_{1},\\beta_{2}) = (0.9,0.99)" + }, + { + "bbox": [ + 305, + 605, + 545, + 641 + ], + "type": "text", + "content": ". The learning rate is set to " + }, + { + "bbox": [ + 305, + 605, + 545, + 641 + ], + "type": "inline_equation", + "content": "10^{-4}" + }, + { + "bbox": [ + 305, + 605, + 545, + 641 + ], + "type": "text", + "content": " in all experiments." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "type": "text", + "content": "We train all of our models on an NVIDIA 3090 GPU. It takes about (30, 2, 6) hours in total, (200, 300, 100) epochs with bath sizes of (32, 32, 4) for our three different stages, respectively. During testing, we select all the models with minimum validation loss. We use a sliding window (window size 300, stride 150) for arbitrary long input audio." + } + ] + } + ], + "index": 26 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "23024" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 103, + 547, + 259 + ], + "blocks": [ + { + "bbox": [ + 46, + 70, + 547, + 95 + ], + "lines": [ + { + "bbox": [ + 46, + 70, + 547, + 95 + ], + "spans": [ + { + "bbox": [ + 46, + 70, + 547, + 95 + ], + "type": "text", + "content": "Table 1: Comparisons with state-of-the-art methods. † denotes our generated results with size " + }, + { + "bbox": [ + 46, + 70, + 547, + 95 + ], + "type": "inline_equation", + "content": "256 \\times 256" + }, + { + "bbox": [ + 46, + 70, + 547, + 95 + ], + "type": "text", + "content": " through a small renderer. The best results are highlighted in **bold**. The number with **underline** denotes the second-best result." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 103, + 547, + 259 + ], + "lines": [ + { + "bbox": [ + 48, + 103, + 547, + 259 + ], + "spans": [ + { + "bbox": [ + 48, + 103, + 547, + 259 + ], + "type": "table", + "html": "
MethodTestset A from LSP [22]Testset B from HDTF [51]
NIQE ↓LMD-v ↓LMD ↓Sync ↑MA ↑NIQE ↓LMD-v ↓LMD ↓Sync ↑MA ↑
MakeItTalk (SIGGRAPH Asia'20 [54])7.072.302.653.070.488.181.912.233.900.53
Wav2Lip (MM'20 [29])7.311.951.815.580.647.832.081.975.780.51
Wav2Lip-GAN (MM'20 [29])7.242.111.835.470.627.772.011.985.780.51
LSP (SIGGRAPH Asia'21 [22])5.752.282.063.090.617.121.672.014.110.52
AD-NeRF (ICCV'21 [10])5.812.892.772.980.41-----
SadTalker (CVPR'23 [50])5.802.512.314.140.567.072.432.373.960.51
GeneFace (ICLR'23 [44])6.612.222.173.080.65-----
Ground Truth (reference)5.280.000.004.891.006.380.000.006.071.00
Ours †5.771.741.514.520.707.051.602.044.340.59
Ours5.551.791.504.480.696.921.591.964.160.56
", + "image_path": "6f77d569b3f569f92187ec2819b96a55e6e5f6516f890ec85c8c3bbd5c3d40d8.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 264, + 128, + 277 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 264, + 128, + 277 + ], + "spans": [ + { + "bbox": [ + 47, + 264, + 128, + 277 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 284, + 164, + 297 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 284, + 164, + 297 + ], + "spans": [ + { + "bbox": [ + 47, + 284, + 164, + 297 + ], + "type": "text", + "content": "4.1. Experimental Setup" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 303, + 287, + 482 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 303, + 287, + 482 + ], + "spans": [ + { + "bbox": [ + 46, + 303, + 287, + 482 + ], + "type": "text", + "content": "Dataset pre-processing. We evaluate our method on two publicly available datasets, i.e., HDTF [51] and Video samples from LSP [22] (LSP dataset). Each video contains a high-resolution portrait with an audio track. The average video length is 1-5 minutes and we process them at 25 fps. We randomly select " + }, + { + "bbox": [ + 46, + 303, + 287, + 482 + ], + "type": "inline_equation", + "content": "80\\%" + }, + { + "bbox": [ + 46, + 303, + 287, + 482 + ], + "type": "text", + "content": " of them for training and the remaining videos for evaluation. Specifically, we get 132 videos for training and 32 videos for evaluation. Each video is cropped to keep the face at the center and then resized to " + }, + { + "bbox": [ + 46, + 303, + 287, + 482 + ], + "type": "inline_equation", + "content": "512 \\times 512" + }, + { + "bbox": [ + 46, + 303, + 287, + 482 + ], + "type": "text", + "content": ". The LSP dataset contains 5 different target sequences of 4 different subjects for training and testing. These sequences span a range of 3-5 minutes. All videos are extracted at 25 fps and the synchronized audio is sampled at " + }, + { + "bbox": [ + 46, + 303, + 287, + 482 + ], + "type": "inline_equation", + "content": "16K\\mathrm{Hz}" + }, + { + "bbox": [ + 46, + 303, + 287, + 482 + ], + "type": "text", + "content": " frequency. We split videos as " + }, + { + "bbox": [ + 46, + 303, + 287, + 482 + ], + "type": "inline_equation", + "content": "80\\% / 20\\%" + }, + { + "bbox": [ + 46, + 303, + 287, + 482 + ], + "type": "text", + "content": " for training and validation." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 483, + 287, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 483, + 287, + 602 + ], + "spans": [ + { + "bbox": [ + 46, + 483, + 287, + 602 + ], + "type": "text", + "content": "We detect 478 3D facial landmarks for all videos using Mediapipe*. Then we estimate the head pose " + }, + { + "bbox": [ + 46, + 483, + 287, + 602 + ], + "type": "inline_equation", + "content": "H" + }, + { + "bbox": [ + 46, + 483, + 287, + 602 + ], + "type": "text", + "content": " for all videos using method [9]. According to these head poses, the 3D facial landmarks are projected to the canonical space through rigid transformation. We extract the 3D mouth points, and eye-related points as " + }, + { + "bbox": [ + 46, + 483, + 287, + 602 + ], + "type": "inline_equation", + "content": "P^M" + }, + { + "bbox": [ + 46, + 483, + 287, + 602 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 483, + 287, + 602 + ], + "type": "inline_equation", + "content": "P^E" + }, + { + "bbox": [ + 46, + 483, + 287, + 602 + ], + "type": "text", + "content": " for each frame. The torso points are estimated from the boundary of the shoulders, which is detected through the face parsing algorithm†. For more data pre-processing details please refer to our supplement materials." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 603, + 288, + 675 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 603, + 288, + 675 + ], + "spans": [ + { + "bbox": [ + 46, + 603, + 288, + 675 + ], + "type": "text", + "content": "Evaluation metrics. We demonstrate the superiority of our method on multiple metrics that are widely involved in the talking portrait field. To evaluate the correctness of generated mouth, we use mouth landmark distance (LMD) and velocity of mouth landmark distance (LMD-" + }, + { + "bbox": [ + 46, + 603, + 288, + 675 + ], + "type": "inline_equation", + "content": "\\upsilon" + }, + { + "bbox": [ + 46, + 603, + 288, + 675 + ], + "type": "text", + "content": ") between generated video and reference video in canonical space. In" + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 308, + 261, + 545, + 571 + ], + "blocks": [ + { + "bbox": [ + 308, + 261, + 545, + 571 + ], + "lines": [ + { + "bbox": [ + 308, + 261, + 545, + 571 + ], + "spans": [ + { + "bbox": [ + 308, + 261, + 545, + 571 + ], + "type": "image", + "image_path": "0271c542186ab66eee211f430b89c1a4bb6a0836b6b82ea9bf4ee33bcae07aaa.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 338, + 578, + 512, + 590 + ], + "lines": [ + { + "bbox": [ + 338, + 578, + 512, + 590 + ], + "spans": [ + { + "bbox": [ + 338, + 578, + 512, + 590 + ], + "type": "text", + "content": "Figure 4: Visual comparison of 5 methods." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "content": "addition, we also calculate the Insertion-over-Union (IoU) for the overlap between the predicted mouth area and the ground truth area (MA). We use the confidence score from SyncNet (Sync) [29] to measure the audio-video synchronization. Since the result cannot be perfectly aligned with the ground-truth video, we use Natural Image Quality Evaluator (NIQE) [24] as the metric for image quality. NIQE is able to capture the naturalness of image details, it is widely used in blind image quality assessment." + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 47, + 683, + 270, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 683, + 270, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 683, + 270, + 713 + ], + "type": "text", + "content": "\\*https://google.github.io/mediapipe/ " + }, + { + "bbox": [ + 47, + 683, + 270, + 713 + ], + "type": "inline_equation", + "content": "\\dagger" + }, + { + "bbox": [ + 47, + 683, + 270, + 713 + ], + "type": "text", + "content": " https://github.com/zllrunning/face-parsing. PyTorch" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "footer", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "23025" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 71, + 286, + 196 + ], + "blocks": [ + { + "bbox": [ + 50, + 71, + 286, + 196 + ], + "lines": [ + { + "bbox": [ + 50, + 71, + 286, + 196 + ], + "spans": [ + { + "bbox": [ + 50, + 71, + 286, + 196 + ], + "type": "image", + "image_path": "e2e78a4c0748ce01e56e335989a797f5e47305cbe8bb8499b2f6b5616eba8cc3.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 50, + 203, + 282, + 216 + ], + "lines": [ + { + "bbox": [ + 50, + 203, + 282, + 216 + ], + "spans": [ + { + "bbox": [ + 50, + 203, + 282, + 216 + ], + "type": "text", + "content": "Figure 5: Multimodal results with the same mouth shape." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 225, + 189, + 238 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 225, + 189, + 238 + ], + "spans": [ + { + "bbox": [ + 47, + 225, + 189, + 238 + ], + "type": "text", + "content": "4.2. Quantitative Comparison" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 244, + 289, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 244, + 289, + 495 + ], + "spans": [ + { + "bbox": [ + 46, + 244, + 289, + 495 + ], + "type": "text", + "content": "We compare our method with several state-of-the-art one-shot talking portrait generation works (LSP [22], MakeItTalk [54], Wav2Lip [29], AD-NeRF [10], SadTalker [50], and GeneFace [44]). For MakeItTalk, Wav2Lip, and SadTalker, the evaluation is performed on their publicly available checkpoint directly. Since these methods only generate low-resolution results, we retrained a small portrait renderer to generate low-resolution results for a fair comparison. The rest methods are retrained on our dataset under the same condition. Note that AD-NeRF and GeneFace are NeRF-based methods that are extremely time-consuming on all videos, we only provide the numerical results on the LSP dataset. As shown in Tab. 1, the proposed method achieves the best overall video quality (lowest NIQE, 5.25) and the correctness of audio-lip synchronization (lowest LMD, LMD-" + }, + { + "bbox": [ + 46, + 244, + 289, + 495 + ], + "type": "inline_equation", + "content": "v" + }, + { + "bbox": [ + 46, + 244, + 289, + 495 + ], + "type": "text", + "content": ", and highest MA). Our method also shows comparable performance with other fully talking-head generation methods in terms of lip-sync score. Please note that a higher sync score is not always lead to better results since it is too sensitive to the audio where unnatural lip movements may get a better score [50]." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 503, + 176, + 514 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 503, + 176, + 514 + ], + "spans": [ + { + "bbox": [ + 47, + 503, + 176, + 514 + ], + "type": "text", + "content": "4.3. Qualitative Evaluation" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 521, + 287, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 521, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 46, + 521, + 287, + 689 + ], + "type": "text", + "content": "User Study. We conduct user studies with 20 attendees on 30 videos generated by ours and the other methods. The driving audio is selected from four different languages: English, Chinese, Japanese, and German. The videos are generated across 5 subjects. Each participant is asked to select the best generated talking-portrait videos based on three major aspects: lip synchronization accuracy, the naturalness of movements including head movement, eye blinking, and upper body movement, and the video quality of the generated portrait. We collect the voting results and calculate the best-voting percentage of each method. The statistics are reported in Tab. 2. Overall, users prefer our results on lip synchronization, the naturalness of portrait, and video quality, indicating the effectiveness of the proposed method." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "type": "text", + "content": "Qualitative comparison. Fig. 4 demonstrates the visual comparison among different methods. The results from" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 72, + 545, + 179 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 179 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 179 + ], + "type": "text", + "content": "LSP [22] have some warping effects without 3D consistency. Wav2Lip [29] can generate accurate mouth motions. However, their mouth areas usually have blurry boundaries and artifacts, which make the video unnatural. The results from AD-NeRF [10] have blurry boundaries of shoulders. SadTalker [50] may suffer from out of sync. GeneFace [44] has obvious artifacts on the neck region. Compared to these methods, our system generates portrait videos with overall high-quality and natural mouth movements." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 180, + 545, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 180, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 304, + 180, + 545, + 251 + ], + "type": "text", + "content": "Diverse outputs. Fig. 5 shows the diverse rendered videos that are driven by the same audio. These videos have different head poses, eye-blinking, and upper bodies while sharing the same mouth structures. These results demonstrate that our MODA network is able to generate vivid and diverse talking portrait videos." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 260, + 525, + 272 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 260, + 525, + 272 + ], + "spans": [ + { + "bbox": [ + 305, + 260, + 525, + 272 + ], + "type": "text", + "content": "4.4. Ablation Study and Performance Analysis" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 278, + 545, + 301 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 278, + 545, + 301 + ], + "spans": [ + { + "bbox": [ + 304, + 278, + 545, + 301 + ], + "type": "text", + "content": "We conduct ablation studies on dual-attention in MODA, FaCo-Net, and TPE in portrait renderer." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 302, + 546, + 445 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 302, + 546, + 445 + ], + "spans": [ + { + "bbox": [ + 304, + 302, + 546, + 445 + ], + "type": "text", + "content": "Dual-attention module. We choose to 1) replace DualAttn with a multi-layer LSTM block [12]; 2) remove the specific attention branch and 3) remove the multimodal attention branch to evaluate the effectiveness of the dual-attention module. Numerical results on LSP test set are reported in Tab. 3. Using LSTM block cannot generate multimodal results and the diverse score (here we use the variance of the generated facial landmarks) drops to 0. When removing the specific attention branch from the dual attention block, the MODA generates the over-smoothed lip movement, which may be out of lip synchronization and has large LMD and LMD-" + }, + { + "bbox": [ + 304, + 302, + 546, + 445 + ], + "type": "inline_equation", + "content": "v" + }, + { + "bbox": [ + 304, + 302, + 546, + 445 + ], + "type": "text", + "content": " errors." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 446, + 545, + 564 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 446, + 545, + 564 + ], + "spans": [ + { + "bbox": [ + 304, + 446, + 545, + 564 + ], + "type": "text", + "content": "FaCo-Net. The FaCo-Net aims to generate natural and consistent representations for our portrait renderer. We carry out an ablation study on it by removing this stage and directly replacing the eye landmarks and mouth landmarks with facial dense landmarks. Fig. 6a shows that condition images without FaCo-Net contain incorrect connections in the lip area and lose face details, leading to low SSIM " + }, + { + "bbox": [ + 304, + 446, + 545, + 564 + ], + "type": "inline_equation", + "content": "(0.871\\rightarrow 0.843)" + }, + { + "bbox": [ + 304, + 446, + 545, + 564 + ], + "type": "text", + "content": ", PSNR " + }, + { + "bbox": [ + 304, + 446, + 545, + 564 + ], + "type": "inline_equation", + "content": "(24.77\\rightarrow 21.96)" + }, + { + "bbox": [ + 304, + 446, + 545, + 564 + ], + "type": "text", + "content": " and NIQE " + }, + { + "bbox": [ + 304, + 446, + 545, + 564 + ], + "type": "inline_equation", + "content": "(5.55\\rightarrow 6.71)" + }, + { + "bbox": [ + 304, + 446, + 545, + 564 + ], + "type": "text", + "content": " rendered images (as in Tab. 4). These results consistently prove the effectiveness of FaCo-Net." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 565, + 545, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 565, + 545, + 613 + ], + "spans": [ + { + "bbox": [ + 304, + 565, + 545, + 613 + ], + "type": "text", + "content": "Temporally positional encoding. We adopt the temporal consistency metric to measure to evaluate the frame-wise consistency (TCM [37]) of the generated videos. Specifically, the TCM is defined as" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 312, + 622, + 545, + 654 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 622, + 545, + 654 + ], + "spans": [ + { + "bbox": [ + 312, + 622, + 545, + 654 + ], + "type": "interline_equation", + "content": "\\mathrm {T C M} = \\frac {1}{T} \\sum_ {t} ^ {T} \\exp \\left(- \\frac {\\left| \\left| O _ {t} - \\operatorname {w a r p} \\left(O _ {t - 1}\\right) \\right| \\right| ^ {2}}{\\left| \\left| V _ {t} - \\operatorname {w a r p} \\left(V _ {t - 1}\\right) \\right| \\right| ^ {2}} - 1\\right), \\tag {16}", + "image_path": "0928dc979ad137b2f771bf87ef2863b4f2418950802fdc9a078a6dd42f480d92.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "O_{t}" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "V_{t}" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": " represent the " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "t^{th}" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": " frame in the referenced video (O) and generated video (V), respectively. " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\operatorname{warp}(\\cdot)" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": " is the warping function using the optical flow [13]. The 2-norm of a matrix " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "||\\cdot||" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": " is the sum of squares of its elements." + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 741 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 741 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 741 + ], + "type": "text", + "content": "23026" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 52, + 92, + 542, + 165 + ], + "blocks": [ + { + "bbox": [ + 129, + 71, + 463, + 84 + ], + "lines": [ + { + "bbox": [ + 129, + 71, + 463, + 84 + ], + "spans": [ + { + "bbox": [ + 129, + 71, + 463, + 84 + ], + "type": "text", + "content": "Table 2: User study analyses measured by best-voting percentage. Higher is better." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 52, + 92, + 542, + 165 + ], + "lines": [ + { + "bbox": [ + 52, + 92, + 542, + 165 + ], + "spans": [ + { + "bbox": [ + 52, + 92, + 542, + 165 + ], + "type": "table", + "html": "
ApproachLow resolution (256 × 256)High resolution (512 × 512)
MakeItTalk [54]Wav2lip [29]SadTalker [50]OursLSP [22]AD-NeRF [10]GeneFace [44]Ours
Lip-sync accuracy15.2%30.5%16.5%37.6%24.6%7.9%19.0%48.5%
Naturalness of movement12.8%14.0%18.6%54.5%19.0%6.3%7.1%67.6%
Image quality8.3%7.2%14.3%70.0%22.8%11.1%16.7%49.7%
", + "image_path": "6ded44c506e3aaafaa7fc8a882b1d9bc35a909e850ec888659e954524b90d374.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 51, + 175, + 201, + 240 + ], + "blocks": [ + { + "bbox": [ + 51, + 175, + 201, + 240 + ], + "lines": [ + { + "bbox": [ + 51, + 175, + 201, + 240 + ], + "spans": [ + { + "bbox": [ + 51, + 175, + 201, + 240 + ], + "type": "image", + "image_path": "aa523b32c9e3912c9914acebe57e5786d853fd699327d1bb6f072788a5820c1c.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 220, + 175, + 545, + 241 + ], + "blocks": [ + { + "bbox": [ + 220, + 175, + 545, + 241 + ], + "lines": [ + { + "bbox": [ + 220, + 175, + 545, + 241 + ], + "spans": [ + { + "bbox": [ + 220, + 175, + 545, + 241 + ], + "type": "image", + "image_path": "06675cee64f954c3b161bea895b7882631ff84568a81d7a916a1632c53aa4360.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 50, + 242, + 200, + 305 + ], + "blocks": [ + { + "bbox": [ + 50, + 242, + 200, + 305 + ], + "lines": [ + { + "bbox": [ + 50, + 242, + 200, + 305 + ], + "spans": [ + { + "bbox": [ + 50, + 242, + 200, + 305 + ], + "type": "image", + "image_path": "4a0fea6cb7e91ce5822cbe57d051c7fb431e2f35893e752bf42ff37f1e565f23.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 67, + 312, + 179, + 322 + ], + "lines": [ + { + "bbox": [ + 67, + 312, + 179, + 322 + ], + "spans": [ + { + "bbox": [ + 67, + 312, + 179, + 322 + ], + "type": "text", + "content": "(a) Effectiveness of FaCo-Net." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 220, + 242, + 545, + 308 + ], + "blocks": [ + { + "bbox": [ + 220, + 242, + 545, + 308 + ], + "lines": [ + { + "bbox": [ + 220, + 242, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 220, + 242, + 545, + 308 + ], + "type": "image", + "image_path": "e211b0474c29e01bdabbfdecb17f55409b9187ecc8087cfa493c7f235c312608.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 334, + 312, + 427, + 322 + ], + "lines": [ + { + "bbox": [ + 334, + 312, + 427, + 322 + ], + "spans": [ + { + "bbox": [ + 334, + 312, + 427, + 322 + ], + "type": "text", + "content": "(b) Effectiveness of TPE." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 132, + 332, + 460, + 345 + ], + "lines": [ + { + "bbox": [ + 132, + 332, + 460, + 345 + ], + "spans": [ + { + "bbox": [ + 132, + 332, + 460, + 345 + ], + "type": "text", + "content": "Figure 6: Ablation studies on FaCo-Net (a) and temporal positional encoding (b)." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 50, + 389, + 285, + 462 + ], + "blocks": [ + { + "bbox": [ + 47, + 364, + 286, + 388 + ], + "lines": [ + { + "bbox": [ + 47, + 364, + 286, + 388 + ], + "spans": [ + { + "bbox": [ + 47, + 364, + 286, + 388 + ], + "type": "text", + "content": "Table 3: Ablation study on MODA. Removing dual attention or replacing it with LSTM block has negative effects." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 389, + 285, + 462 + ], + "lines": [ + { + "bbox": [ + 50, + 389, + 285, + 462 + ], + "spans": [ + { + "bbox": [ + 50, + 389, + 285, + 462 + ], + "type": "table", + "html": "
MethodLMD-vLMDDiverse
replace with LSTM2.492.790
w/o multimodal attention3.012.810
w/o specific attention1.801.551.70
Final1.791.501.57
", + "image_path": "92af53edc81f0253bc2258cf521564530b3cd8de37daec099b9a2811562380f8.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 57, + 495, + 278, + 543 + ], + "blocks": [ + { + "bbox": [ + 89, + 475, + 243, + 487 + ], + "lines": [ + { + "bbox": [ + 89, + 475, + 243, + 487 + ], + "spans": [ + { + "bbox": [ + 89, + 475, + 243, + 487 + ], + "type": "text", + "content": "Table 4: Ablation study on FaCo-Net." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 57, + 495, + 278, + 543 + ], + "lines": [ + { + "bbox": [ + 57, + 495, + 278, + 543 + ], + "spans": [ + { + "bbox": [ + 57, + 495, + 278, + 543 + ], + "type": "table", + "html": "
MethodSSIM ↑PSNR ↑NIQE ↓
w/o FaCo-Net Net0.84321.966.71
Final0.87124.775.55
", + "image_path": "aec330b08c7b23e9fc7c0c5557563ade415ee331afd06bde659a47f4d0487191.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_body" + } + ], + "index": 12 + }, + { + "type": "table", + "bbox": [ + 69, + 574, + 263, + 622 + ], + "blocks": [ + { + "bbox": [ + 67, + 554, + 266, + 567 + ], + "lines": [ + { + "bbox": [ + 67, + 554, + 266, + 567 + ], + "spans": [ + { + "bbox": [ + 67, + 554, + 266, + 567 + ], + "type": "text", + "content": "Table 5: Ablation study on TPE. Higher is better." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 69, + 574, + 263, + 622 + ], + "lines": [ + { + "bbox": [ + 69, + 574, + 263, + 622 + ], + "spans": [ + { + "bbox": [ + 69, + 574, + 263, + 622 + ], + "type": "table", + "html": "
MethodTCM ↑
Renderer w/o TPE0.63
Renderer with TPE0.71
", + "image_path": "0fc33675f1966d649a3a4fd72c050446dcf35cb410321174bb488a5e96ed8e46.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "table_body" + } + ], + "index": 14 + }, + { + "bbox": [ + 46, + 629, + 287, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 287, + 712 + ], + "type": "text", + "content": "Through this equation, the generated video (V) is encouraged to be temporally consistent according to variations in the reference video (O). Fig. 6b demonstrates the comparison of video sequences with/without TPE. We find TPE can stabilize video synthesis, especially when training videos with changing backgrounds. Numerical results in Tab. 5 also show that TPE can increase TCM score." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 365, + 467, + 377 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 365, + 467, + 377 + ], + "spans": [ + { + "bbox": [ + 306, + 365, + 467, + 377 + ], + "type": "text", + "content": "5. Discussions and Conclusions" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 393, + 545, + 598 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 393, + 545, + 598 + ], + "spans": [ + { + "bbox": [ + 304, + 393, + 545, + 598 + ], + "type": "text", + "content": "We present a deep learning approach for synthesizing multimodal photorealistic talking-portrait animation from audio streams. Our method can render multiple personalized talking styles with arbitrary audio. Our system contains three stages, i.e., MODA, FaCo-Net, and a high-fidelity portrait renderer with temporal guidance. The first stage generates lip motion, head motion, eye blinking, and torso motion with a unified network. This network adopts a dual-attention mechanism and is able to generate diverse talking-portrait representations with correct lip synchronization. The second stage generates fine-grained facial dense landmarks powered by generated lip motion and eye blinking. Finally, we generate the intermediate representations for our temporal-guided renderer to synthesize both high-fidelity and stable talk-portrait videos. Experimental results and user studies show the superiority of our method. Analytical experiments have also verified different parts of our system." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 605, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 546, + 714 + ], + "type": "text", + "content": "Limitations and future work. While our approach achieves impressive results in a wide variety of scenarios, there still exist several limitations. Similar to most deep learning-based methods, our method cannot generalize well on unseen subjects or extremely out-of-domain audio. It may require fine-tuning the renderer for new avatars. We also looking forward to future work to find a person-invariant renderer to achieve high-quality synthesis without additional finetuning." + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "23027" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 92, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 18, + "blocks": [ + { + "bbox": [ + 53, + 92, + 287, + 125 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 92, + 287, + 125 + ], + "spans": [ + { + "bbox": [ + 53, + 92, + 287, + 125 + ], + "type": "text", + "content": "[1] Iz Beltagy, Matthew E Peters, and Arman Cohan. Longformer: The long-document transformer. arXiv preprint arXiv:2004.05150, 2020. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 126, + 287, + 159 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 126, + 287, + 159 + ], + "spans": [ + { + "bbox": [ + 53, + 126, + 287, + 159 + ], + "type": "text", + "content": "[2] Lele Chen, Guofeng Cui, Celong Liu, Zhong Li, Ziyi Kou, Yi Xu, and Chenliang Xu. Talking-head generation with rhythmic head motion. In ECCV, 2020. 1" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 161, + 287, + 195 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 161, + 287, + 195 + ], + "spans": [ + { + "bbox": [ + 53, + 161, + 287, + 195 + ], + "type": "text", + "content": "[3] Lele Chen, Ross K. Maddox, Zhiyao Duan, and Chenliang Xu. Hierarchical cross-modal talking face generation with dynamic pixel-wise loss. In CVPR, 2019. 1" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 197, + 287, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 197, + 287, + 228 + ], + "spans": [ + { + "bbox": [ + 53, + 197, + 287, + 228 + ], + "type": "text", + "content": "[4] Joon Son Chung, Andrew Senior, Oriol Vinyals, and Andrew Zisserman. Lip reading sentences in the wild. In CVPR, 2017. 1, 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 231, + 287, + 264 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 231, + 287, + 264 + ], + "spans": [ + { + "bbox": [ + 53, + 231, + 287, + 264 + ], + "type": "text", + "content": "[5] Pif Edwards, Chris Landreth, Eugene Fume, and Karan Singh. Jali: an animator-centric viseme model for expressive lip synchronization. TOG, 35(4):1-11, 2016. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 266, + 287, + 299 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 266, + 287, + 299 + ], + "spans": [ + { + "bbox": [ + 53, + 266, + 287, + 299 + ], + "type": "text", + "content": "[6] Yingruo Fan, Zhaojiang Lin, Jun Saito, Wenping Wang, and Taku Komura. Faceformer: Speech-driven 3d facial animation with transformers. In CVPR, 2022. 1, 2, 4" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 300, + 287, + 333 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 300, + 287, + 333 + ], + "spans": [ + { + "bbox": [ + 53, + 300, + 287, + 333 + ], + "type": "text", + "content": "[7] Guy Gafni, Justus Thies, Michael Zollhofer, and Matthias Nießner. Dynamic neural radiance fields for monocular 4d facial avatar reconstruction. In CVPR, 2021. 1" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 335, + 287, + 378 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 335, + 287, + 378 + ], + "spans": [ + { + "bbox": [ + 53, + 335, + 287, + 378 + ], + "type": "text", + "content": "[8] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In NeurIPS, 2014. 1, 5" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 380, + 287, + 414 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 380, + 287, + 414 + ], + "spans": [ + { + "bbox": [ + 53, + 380, + 287, + 414 + ], + "type": "text", + "content": "[9] Jianzhu Guo, Xiangyu Zhu, Yang Yang, Fan Yang, Zhen Lei, and Stan Z Li. Towards fast, accurate and stable 3d dense face alignment. In ECCV, 2020. 6" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 415, + 287, + 459 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 415, + 287, + 459 + ], + "spans": [ + { + "bbox": [ + 48, + 415, + 287, + 459 + ], + "type": "text", + "content": "[10] Yudong Guo, Keyu Chen, Sen Liang, Yong-Jin Liu, Hujun Bao, and Juyong Zhang. Ad-nerf: Audio driven neural radiance fields for talking head synthesis. In ICCV, 2021. 2, 6, 7, 8, 12, 14" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 460, + 287, + 505 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 460, + 287, + 505 + ], + "spans": [ + { + "bbox": [ + 48, + 460, + 287, + 505 + ], + "type": "text", + "content": "[11] Kai Han, Yunhe Wang, Hanting Chen, Xinghao Chen, Jianyuan Guo, Zhenhua Liu, Yehui Tang, An Xiao, Chunjing Xu, Yixing Xu, et al. A survey on vision transformer. PAMI, 45(1):87-110, 2022. 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 506, + 287, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 506, + 287, + 529 + ], + "spans": [ + { + "bbox": [ + 48, + 506, + 287, + 529 + ], + "type": "text", + "content": "[12] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 9(8):1735-1780, 1997. 7" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 530, + 287, + 552 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 530, + 287, + 552 + ], + "spans": [ + { + "bbox": [ + 48, + 530, + 287, + 552 + ], + "type": "text", + "content": "[13] Berthold KP Horn and Brian G Schunck. Determining optical flow. Artificial intelligence, 17(1-3):185–203, 1981. 7" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 554, + 287, + 597 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 554, + 287, + 597 + ], + "spans": [ + { + "bbox": [ + 48, + 554, + 287, + 597 + ], + "type": "text", + "content": "[14] Xinya Ji, Hang Zhou, Kaisiyuan Wang, Qianyi Wu, Wayne Wu, Feng Xu, and Xun Cao. Eamm: One-shot emotional talking face via audio-based emotion-aware motion model. In SIGGRAPH, 2022. 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 600, + 287, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 600, + 287, + 643 + ], + "spans": [ + { + "bbox": [ + 48, + 600, + 287, + 643 + ], + "type": "text", + "content": "[15] Tero Karras, Timo Aila, Samuli Laine, Antti Herva, and Jaakko Lehtinen. Audio-driven facial animation by joint end-to-end learning of pose and emotion. TOG, 36(4):1-12, 2017. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 646, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 646, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 646, + 287, + 689 + ], + "type": "text", + "content": "[16] Salman Khan, Muzammal Naseer, Munawar Hayat, Syed Waqas Zamir, Fahad Shahbaz Khan, and Mubarak Shah. Transformers in vision: A survey. arXiv preprint arXiv:2101.01169, 2021. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "text", + "content": "[17] D. P. Kingma and M. Welling. Auto-encoding variational bayes. In ICLR, 2014. 5" + } + ] + } + ], + "index": 17 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 36, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "text", + "content": "[18] Prajwal KR, Rudrabha Mukhopadhyay, Jerin Philip, Abhishek Jha, Vinay Namboodiri, and CV Jawahar. Towards automatic face-to-face translation. In ACMMM, 2019. 1" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 107, + 545, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 149 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 149 + ], + "type": "text", + "content": "[19] Avisek Lahiri, Vivek Kwatra, Christian Frueh, John Lewis, and Chris Bregler. Lipsync3d: Data-efficient learning of personalized 3d talking faces from video using pose and lighting normalization. In CVPR, 2021. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 151, + 545, + 182 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 151, + 545, + 182 + ], + "spans": [ + { + "bbox": [ + 307, + 151, + 545, + 182 + ], + "type": "text", + "content": "[20] Ming-Yu Liu, Thomas Breuel, and Jan Kautz. Unsupervised image-to-image translation networks. In NeurIPS, 2017. 3, 5" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 184, + 545, + 226 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 184, + 545, + 226 + ], + "spans": [ + { + "bbox": [ + 307, + 184, + 545, + 226 + ], + "type": "text", + "content": "[21] Xian Liu, Yinghao Xu, Qianyi Wu, Hang Zhou, Wayne Wu, and Bolei Zhou. Semantic-aware implicit neural audio-driven video portrait generation. In ECCV. Springer, 2022. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 228, + 545, + 260 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 228, + 545, + 260 + ], + "spans": [ + { + "bbox": [ + 307, + 228, + 545, + 260 + ], + "type": "text", + "content": "[22] Yuanxun Lu, Jinxiang Chai, and Xun Cao. Live speech portraits: real-time photorealistic talking-head animation. TOG, 40(6):1-17, 2021. 1, 2, 3, 6, 7, 8, 11, 12, 14" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 261, + 545, + 282 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 261, + 545, + 282 + ], + "spans": [ + { + "bbox": [ + 307, + 261, + 545, + 282 + ], + "type": "text", + "content": "[23] Larry R Medsker and LC Jain. Recurrent neural networks. Design and Applications, 5:64-67, 2001. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 284, + 545, + 316 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 284, + 545, + 316 + ], + "spans": [ + { + "bbox": [ + 307, + 284, + 545, + 316 + ], + "type": "text", + "content": "[24] Anish Mittal, Rajiv Soundararajan, and Alan C Bovik. Making a \"completely blind\" image quality analyzer. IEEE Signal processing letters, 20(3):209-212, 2012. 6" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 317, + 545, + 350 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 317, + 545, + 350 + ], + "spans": [ + { + "bbox": [ + 307, + 317, + 545, + 350 + ], + "type": "text", + "content": "[25] Se Jin Park, Minsu Kim, Joanna Hong, Jeongsoo Choi, and Yong Man Ro. Synctalkface: Talking face generation with precise lip-syncing via audio-lip memory. In AAAI, 2022. 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 350, + 545, + 381 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 350, + 545, + 381 + ], + "spans": [ + { + "bbox": [ + 307, + 350, + 545, + 381 + ], + "type": "text", + "content": "[26] Razvan Pascanu, Tomas Mikolov, and Yoshua Bengio. On the difficulty of training recurrent neural networks. In ICML, 2013. 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 383, + 545, + 436 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 383, + 545, + 436 + ], + "spans": [ + { + "bbox": [ + 307, + 383, + 545, + 436 + ], + "type": "text", + "content": "[27] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, et al. Pytorch: An imperative style, high-performance deep learning library. NeurlPS, 32, 2019. 5" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 437, + 545, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 437, + 545, + 470 + ], + "spans": [ + { + "bbox": [ + 307, + 437, + 545, + 470 + ], + "type": "text", + "content": "[28] Mathis Petrovich, Michael J Black, and Gül Varol. Action-conditioned 3d human motion synthesis with transformer vae. arXiv preprint arXiv:2104.05670, 2021. 5" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 472, + 545, + 514 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 472, + 545, + 514 + ], + "spans": [ + { + "bbox": [ + 307, + 472, + 545, + 514 + ], + "type": "text", + "content": "[29] KR Prajwal, Rudrabha Mukhopadhyay, Vinay P Namboodiri, and CV Jawahar. A lip sync expert is all you need for speech to lip generation in the wild. In ACMMM, 2020. 1, 2, 6, 7, 8, 12" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 307, + 515, + 545, + 557 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 515, + 545, + 557 + ], + "spans": [ + { + "bbox": [ + 307, + 515, + 545, + 557 + ], + "type": "text", + "content": "[30] Steffen Schneider, Alexei Baevski, Ronan Collobert, and Michael Auli. Wav2vec: Unsupervised pre-training for speech recognition. arXiv preprint arXiv:1904.05862, 2019. 3" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 307, + 559, + 545, + 592 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 559, + 545, + 592 + ], + "spans": [ + { + "bbox": [ + 307, + 559, + 545, + 592 + ], + "type": "text", + "content": "[31] Oliver Schreer, Roman Englert, Peter Eisert, and Ralf Tanger. Real-time vision and speech driven avatars for multimedia applications. TMM, 10(3):352-360, 2008. 2" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 307, + 593, + 545, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 593, + 545, + 635 + ], + "spans": [ + { + "bbox": [ + 307, + 593, + 545, + 635 + ], + "type": "text", + "content": "[32] Shuai Shen, Wenliang Zhao, Zibin Meng, Wanhua Li, Zheng Zhu, Jie Zhou, and Jiwen Lu. Difftalk: Crafting diffusion models for generalized talking head synthesis. arXiv preprint arXiv:2301.03786, 2023. 2" + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 307, + 636, + 545, + 669 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 636, + 545, + 669 + ], + "spans": [ + { + "bbox": [ + 307, + 636, + 545, + 669 + ], + "type": "text", + "content": "[33] Aliaksandr Siarohin, Stéphane Lathuilière, Sergey Tulyakov, Elisa Ricci, and Nicu Sebe. First order motion model for image animation. NeurIPS, 32, 2019. 2" + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 307, + 670, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 670, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 670, + 545, + 713 + ], + "type": "text", + "content": "[34] Michal Stypulkowski, Konstantinos Vougioukas, Sen He, Maciej Zięba, Stavros Petridis, and Maja Pantic. Diffused heads: Diffusion models beat gans on talking-face generation. arXiv preprint arXiv:2301.03396, 2023. 2" + } + ] + } + ], + "index": 35 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "23028" + } + ] + } + ], + "index": 37 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[35] Anni Tang, Tianyu He, Xu Tan, Jun Ling, Runnan Li, Sheng Zhao, Li Song, and Jiang Bian. Memories are one-to-many mapping alleviators in talking face generation. arXiv preprint arXiv:2212.05005, 2022. 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 118, + 286, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 118, + 286, + 149 + ], + "spans": [ + { + "bbox": [ + 49, + 118, + 286, + 149 + ], + "type": "text", + "content": "[36] Justus Thies, Mohamed Elgharib, Ayush Tewari, Christian Theobalt, and Matthias Nießner. Neural voice puppetry: Audio-driven facial reenactment. In ECCV, 2020. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 151, + 286, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 151, + 286, + 194 + ], + "spans": [ + { + "bbox": [ + 49, + 151, + 286, + 194 + ], + "type": "text", + "content": "[37] S. Varghese, Y. Bayzidi, A. Bar, N. Kapoor, and T. Fingscheidt. Unsupervised temporal consistency metric for video segmentation in highly-automated driving. In CVPR Workshop, 2020. 7, 11" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 195, + 286, + 227 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 195, + 286, + 227 + ], + "spans": [ + { + "bbox": [ + 49, + 195, + 286, + 227 + ], + "type": "text", + "content": "[38] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In NeurIPS, 2017. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 228, + 286, + 270 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 228, + 286, + 270 + ], + "spans": [ + { + "bbox": [ + 49, + 228, + 286, + 270 + ], + "type": "text", + "content": "[39] Kaisiyuan Wang, Qianyi Wu, Linsen Song, Zhuoqian Yang, Wayne Wu, Chen Qian, Ran He, Yu Qiao, and Chen Change Loy. Mead: A large-scale audio-visual dataset for emotional talking-face generation. In ECCV, 2020. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 272, + 286, + 304 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 272, + 286, + 304 + ], + "spans": [ + { + "bbox": [ + 49, + 272, + 286, + 304 + ], + "type": "text", + "content": "[40] Suzhen Wang, Lincheng Li, Yu Ding, Changjie Fan, and Xin Yu. Audio2head: Audio-driven one-shot talking-head generation with natural head motion. In *IJCAI*, 2021. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 305, + 286, + 337 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 305, + 286, + 337 + ], + "spans": [ + { + "bbox": [ + 49, + 305, + 286, + 337 + ], + "type": "text", + "content": "[41] Ting-Chun Wang, Ming-Yu Liu, Jun-Yan Zhu, Guilin Liu, Andrew Tao, Jan Kautz, and Bryan Catanzaro. Video-to-video synthesis. In NeurIPS, 2018. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 338, + 286, + 371 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 338, + 286, + 371 + ], + "spans": [ + { + "bbox": [ + 49, + 338, + 286, + 371 + ], + "type": "text", + "content": "[42] Xinsheng Wang, Qicong Xie, Jihua Zhu, Lei Xie, et al. Anyonenet: Synchronized speech and talking head generation for arbitrary person. arXiv preprint arXiv:2108.04325, 2021. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 372, + 286, + 415 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 372, + 286, + 415 + ], + "spans": [ + { + "bbox": [ + 49, + 372, + 286, + 415 + ], + "type": "text", + "content": "[43] Shunyu Yao, RuiZhe Zhong, Yichao Yan, Guangtao Zhai, and Xiaokang Yang. Dfa-nerf: Personalized talking head generation via disentangled face attributes neural rendering. arXiv preprint arXiv:2201.00791, 2022. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 416, + 286, + 458 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 416, + 286, + 458 + ], + "spans": [ + { + "bbox": [ + 49, + 416, + 286, + 458 + ], + "type": "text", + "content": "[44] Zhenhui Ye, Ziyue Jiang, Yi Ren, Jinglin Liu, JinZheng He, and Zhou Zhao. Geneface: Generalized and high-fidelity audio-driven 3d talking face synthesis. In ICLR, 2023. 1, 2, 4, 6, 7, 8, 14" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 460, + 286, + 502 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 460, + 286, + 502 + ], + "spans": [ + { + "bbox": [ + 49, + 460, + 286, + 502 + ], + "type": "text", + "content": "[45] Ran Yi, Zipeng Ye, Juyong Zhang, Hujun Bao, and Yong-Jin Liu. Audio-driven talking face video generation with learning-based personalized head pose. arXiv preprint arXiv:2002.10137, 2020. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 49, + 504, + 286, + 536 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 504, + 286, + 536 + ], + "spans": [ + { + "bbox": [ + 49, + 504, + 286, + 536 + ], + "type": "text", + "content": "[46] Zili Yi, Hao Zhang, Ping Tan, and Minglun Gong. Dualgan: Unsupervised dual learning for image-to-image translation. In ICCV, 2017. 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 49, + 537, + 286, + 579 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 537, + 286, + 579 + ], + "spans": [ + { + "bbox": [ + 49, + 537, + 286, + 579 + ], + "type": "text", + "content": "[47] Changqian Yu, Changxin Gao, Jingbo Wang, Gang Yu, Chunhua Shen, and Nong Sang. Bisenet v2: Bilateral network with guided aggregation for real-time semantic segmentation. IJCV, 129:3051-3068, 2021. 12" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 49, + 582, + 286, + 613 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 582, + 286, + 613 + ], + "spans": [ + { + "bbox": [ + 49, + 582, + 286, + 613 + ], + "type": "text", + "content": "[48] Egor Zakharov, Aliaksandra Shysheya, Egor Burkov, and Victor Lempitsky. Few-shot adversarial learning of realistic neural talking head models. In ICCV, 2019. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 49, + 614, + 286, + 657 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 614, + 286, + 657 + ], + "spans": [ + { + "bbox": [ + 49, + 614, + 286, + 657 + ], + "type": "text", + "content": "[49] Chenxu Zhang, Yifan Zhao, Yifei Huang, Ming Zeng, Saifeng Ni, Madhukar Budagavi, and Xiaohu Guo. Facial: Synthesizing dynamic talking face with implicit attribute learning. In ICCV, 2021. 1" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 49, + 658, + 286, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 658, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 49, + 658, + 286, + 712 + ], + "type": "text", + "content": "[50] Wenxuan Zhang, Xiaodong Cun, Xuan Wang, Yong Zhang, Xi Shen, Yu Guo, Ying Shan, and Fei Wang. Sadtalker: Learning realistic 3d motion coefficients for stylized audio-driven single image talking face animation. In CVPR, 2023. 1, 2, 3, 6, 7, 8" + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 308 + ], + "type": "list", + "angle": 0, + "index": 23, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "text", + "content": "[51] Zhimeng Zhang, Lincheng Li, Yu Ding, and Changjie Fan. Flow-guided one-shot talking face generation with a high-resolution audio-visual dataset. In CVPR, 2021. 2, 6" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 108, + 545, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 108, + 545, + 149 + ], + "spans": [ + { + "bbox": [ + 307, + 108, + 545, + 149 + ], + "type": "text", + "content": "[52] Hang Zhou, Yasheng Sun, Wayne Wu, Chen Change Loy, Xiaogang Wang, and Ziwei Liu. Pose-controllable talking face generation by implicitly modularized audio-visual representation. In CVPR, 2021. 1, 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 152, + 545, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 184 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 184 + ], + "type": "text", + "content": "[53] Yijun Zhou and James Gregson. Whenet: Real-time fine-grained estimation for wide range head pose. arXiv preprint arXiv:2005.10353, 2020. 11" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 186, + 545, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 186, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 307, + 186, + 545, + 228 + ], + "type": "text", + "content": "[54] Yang Zhou, Xintong Han, Eli Shechtman, Jose Echevarria, Evangelos Kalogerakis, and Dingzeyu Li. Makelttalk: speaker-aware talking-head animation. TOG, 39(6):1-15, 2020. 1, 2, 3, 6, 7, 8, 12" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 230, + 545, + 273 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 230, + 545, + 273 + ], + "spans": [ + { + "bbox": [ + 307, + 230, + 545, + 273 + ], + "type": "text", + "content": "[55] Yang Zhou, Zhan Xu, Chris Landreth, Evangelos Kalogerakis, Subhransu Maji, and Karan Singh. Visemenet: Audio-driven animator-centric speech animation. TOG, 37(4):1-10, 2018. 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 275, + 545, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 275, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 307, + 275, + 545, + 308 + ], + "type": "text", + "content": "[56] Hao Zhu, Huaibo Huang, Yi Li, Aihua Zheng, and Ran He. Arbitrary talking face generation via attentional audio-visual coherence learning. In IJCAI, 2020. 2" + } + ] + } + ], + "index": 22 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "23029" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/aa32c686-8817-467e-b52a-3ad29e222646_content_list.json b/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/aa32c686-8817-467e-b52a-3ad29e222646_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..4ed133db8a9bac3671331d56ef66d155c32b614a --- /dev/null +++ b/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/aa32c686-8817-467e-b52a-3ad29e222646_content_list.json @@ -0,0 +1,1486 @@ +[ + { + "type": "text", + "text": "MOSE: A New Dataset for Video Object Segmentation in Complex Scenes", + "text_level": 1, + "bbox": [ + 111, + 130, + 857, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Henghui Ding $^{1}$ Chang Liu $^{1}$ Shuting He $^{1}$ Xudong Jiang $^{1}$ Philip H.S. Torr $^{2}$ Song Bai $^{3}$ $^{1}$ Nanyang Technological University $^{2}$ University of Oxford $^{3}$ ByteDance https://henghuiding.github.io/MOSE", + "bbox": [ + 94, + 178, + 872, + 243 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/7ca00a12463ea3b973f42dc175d7440099190cdb6f711027511fb173e4c2806e.jpg", + "image_caption": [ + "Figure 1. Examples of video clips from the coMplex video Object SEgmentation (MOSE) dataset. The selected target objects are masked in orange. The most notable feature of MOSE is complex scenarios, including the disappearance-reappearance of objects, small/inconspicuous objects, heavy occlusions, crowded scenarios, etc. For example, the target player in the 2nd row turns around when reappearing in the 4th and 5th columns after disappearing in the 3rd column, bringing challenges in re-identifying him. Most videos in MOSE contain crowded and occluded objects with the target object seldom being the salient one. The goal of MOSE dataset is to provide a platform that promotes the development of more comprehensive and robust video object segmentation algorithms." + ], + "image_footnote": [], + "bbox": [ + 80, + 265, + 890, + 422 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 539, + 313, + 555 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Video object segmentation (VOS) aims at segmenting a particular object throughout the entire video clip sequence. The state-of-the-art VOS methods have achieved excellent performance (e.g., $90 + \\%$ J&F) on existing datasets. However, since the target objects in these existing datasets are usually relatively salient, dominant, and isolated, VOS under complex scenes has rarely been studied. To revisit VOS and make it more applicable in the real world, we collect a new VOS dataset called coMplex video Object SEgmentation (MOSE) to study the tracking and segmenting objects in complex scenarios. MOSE contains 2,149 video clips and 5,200 objects from 36 categories, with 431,725 high-quality object segmentation masks. The most notable feature of MOSE dataset is complex scenes with crowded and occluded objects. The target objects in the videos are commonly occluded by others and disappear in some frames. To analyze the proposed MOSE dataset, we benchmark 18 existing VOS methods under 4 different settings on the proposed MOSE dataset and conduct comprehensive comparisons. The experiments show that", + "bbox": [ + 75, + 571, + 472, + 875 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "current VOS algorithms cannot well perceive objects in complex scenes. For example, under the semi-supervised VOS setting, the highest $J \\& F$ by existing state-of-the-art VOS methods is only $59.4\\%$ on MOSE, much lower than their $\\sim 90\\%$ $J \\& F$ performance on DAVIS. The results reveal that although excellent performance has been achieved on existing benchmarks, there are unresolved challenges under complex scenes and more efforts are desired to explore these challenges in the future.", + "bbox": [ + 500, + 541, + 893, + 676 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 500, + 708, + 632, + 723 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Video object segmentation (VOS) [73, 74, 97] aims at segmenting a particular object, e.g., the dominant objects or the objects indicated by users, throughout the entire video sequence. It is one of the most fundamental and challenging computer vision tasks and has a crucial role in many piratical applications that involve video analysis and understanding, e.g., self-driving vehicle, augmented reality, video editing, etc. There are many different settings for VOS, for example, semi-supervised VOS [4, 71] that gives the first-frame mask of the target object, unsupervised VOS [14, 33] that automatically finds primary objects, and", + "bbox": [ + 496, + 734, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "henghui.ding@gmail.com", + "bbox": [ + 99, + 887, + 258, + 900 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "20224", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "interactive VOS [9, 68] that relies on the user's interactions of the target object. Video object segmentation has been extensively studied in the past using traditional techniques or deep learning methods. Especially, the deep-learning-based methods have greatly improved the performance of video object segmentation and surpassed the traditional techniques by a large margin.", + "bbox": [ + 75, + 90, + 470, + 196 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Current state-of-the-art methods have achieved very high performance on two of the most commonly-used VOS datasets DAVIS [73, 74] and YouTube-VOS [97]. For example, XMem [10] achieves $92.0\\%$ $\\mathcal{J}\\& F$ on DAVIS 2016 [73], $87.7\\%$ $\\mathcal{J}\\& F$ on DAVIS 2017 [74], and $86.1\\%$ $\\mathcal{G}$ on YouTube-VOS [97]. With such a high performance, it seems that the video object segmentation has been well resolved. However, do we really perceive objects in realistic scenarios? To answer this question, we revisit video object segmentation under realistic and more complex scenes. The target objects in existing datasets [73, 74, 97] are usually salient and dominant. In real-world scenarios, isolated and salient objects rarely appear while complex and occluded scenes happen frequently. To evaluate current state-of-the-art VOS methods under more complex scenarios, we collect 2,149 videos with complex scenes and form a new large-scale challenging video object segmentation benchmark, termed coMplex video Object SEgmentation (MOSE). Specifically, there are 5,200 objects from 36 categories in MOSE, with 431,725 high-quality segmentation masks. As shown in Figure 1, the most notable feature of MOSE is complex scenarios, including disappearance-reappearance of objects, small/inconspicuous objects, heavy occlusions, crowded scenarios, etc. For example, the white sedan in the first row of Figure 1 is occluded by the bus, and the heaviest occlusion in 3rd image makes the sedan totally disappear. In the second row of Figure 1, the target player in the crowd is inconspicuous and disappears in the third frame due to the occlusions of the crowd. When the target player reappears, he turns around and shows a different appearance from the first two frames, which makes him very difficult to be tracked. The heavy occlusion and disappearance of objects under complex scenes bring great challenges to video object segmentation. We wish to promote video object segmentation research in complex environments and make VOS applicable in the real world.", + "bbox": [ + 75, + 200, + 472, + 761 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To analyze the proposed MOSE dataset, we retrain and evaluate some existing VOS methods on MOSE. Specifically, we retrain 6 state-of-the-art methods under the semi-supervised setting using mask as the first-frame reference, 2 methods under the semi-supervised setting using bounding box as the first-frame reference, 3 methods under the multi-object zero-shot video object segmentation setting, and 7 methods under interactive setting. The experimental results show that videos of complex scenes make the current", + "bbox": [ + 75, + 763, + 470, + 902 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "state-of-the-art VOS methods less pronounced, especially in terms of tracking objects that disappear for a while due to occlusions. For example, the $J \\& F$ performance of XMem [10] on DAVIS 2016 is $92.0\\%$ but drop to $57.6\\%$ on MOSE, the $J \\& F$ performance of DeAOT [104] on DAVIS 2016 is $92.9\\%$ but drop to $59.4\\%$ on MOSE, which consistently reveal the difficulties brought by complex scenes.", + "bbox": [ + 496, + 90, + 890, + 196 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The poor performance on MOSE is due to not only occlusions/crowds/small-scale in static images but also objects' disappearance-reappearance and flickering across the temporal domain. While the heavy occlusions, crowds, and small objects bring challenges to the segmentation of objects in images, the disappearance-reappearance of objects makes it extremely difficult to track an occluded object, increasing the challenge of association.", + "bbox": [ + 496, + 198, + 890, + 318 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In a summary, our main contributions are as follows:", + "bbox": [ + 517, + 319, + 867, + 334 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We build a new video object segmentation benchmark dataset termed MOSE (coMplex video Object SEgmentation). MOSE focuses on understanding objects in videos under complex environments.", + "- We conduct comprehensive comparison and evaluation of state-of-the-art VOS methods on the MOSE dataset under 4 different settings, including mask-initialization semi-supervised, box-initialization semi-supervised, unsupervised, and interactive settings.", + "- Taking a close look at MOSE, we analyze the challenges and potential directions for future video understanding research in complex scenes." + ], + "bbox": [ + 516, + 348, + 890, + 545 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 561, + 640, + 578 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Video Object Segmentation (VOS)", + "text_level": 1, + "bbox": [ + 500, + 588, + 799, + 604 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Video object segmentation (VOS) aims at segmenting a particular object throughout the entire video clip sequence. According to how to indicate the particular object, there are mainly four different settings, i.e., semi-supervised VOS (or semi-automatic VOS [89] or one-shot VOS), unsupervised VOS (or automatic VOS [89] or zero-shot VOS), interactive VOS, and referring VOS.", + "bbox": [ + 496, + 612, + 890, + 718 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "- Semi-supervised VOS. Semi-supervised video object segmentation (or one-shot video object segmentation) [4] gives the first frame object mask and target to segment the target object throughout the remaining video frames. Most existing works can be categorized into propagation-based methods [8, 13, 25, 30–32, 34, 35, 51, 72, 94, 95, 97, 98, 109] and matching-based methods [13, 21, 22, 29, 40, 69, 85, 91, 102, 107, 111]. The propagation-based methods utilize the mask of previous frame to guide the mask generation of the current frame, propagating the clues of target object frame by frame. The matching-based methods memorize the embedding of target object and then conduct per-pixel", + "bbox": [ + 496, + 719, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "20225", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "classification to measure the similarity of each pixel's feature to the embedding of target object.", + "bbox": [ + 76, + 90, + 468, + 119 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Since pixel-wise masks are hard to be obtained, some semi-supervised VOS works propose utilize bounding box as the first-frame clue to indicate the target object [50, 81, 86]. For example, SiamMask [86] applies a mask prediction branch on fully-convolutional Siamese object tracker to generate binary segmentation masks.", + "bbox": [ + 76, + 122, + 467, + 212 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "- Interactive VOS. Interactive video object segmentation is a special form of semi-supervised video object segmentation [6, 9, 11, 13, 28, 66, 68, 106], it aims at segmenting the target object in a video indicated by user's interaction, e.g., clicks or scribbles. Existing interactive VOS mainly follows a paradigm of interaction-propagation way. Besides the feature encoder that extracts discriminative pixel features, there are other two modules placed on the feature encoder to achieve interactive video object segmentation, i.e., interactive segmentation module that corrects prediction based on user's interaction and mask propagation module that propagates user-corrected masks to other frames.", + "bbox": [ + 75, + 213, + 467, + 393 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "- Referring VOS. Referring video object segmentation [19, 79, 105] is an emerging setting that involves multi-modal information. It gives a natural language expression to indicate the target object and aims at segmenting the target object throughout the video clips. Existing referring video object segmentation methods can be categorized into two ways: bottom-up methods and top-down methods. Bottom-up methods [20, 56, 79] directly segment the target object at the first frame and propagate the mask to the remaining frames, or conduct image segmentation on each frame independently and then associate these masks. Top-down methods [2, 49, 93] exhaustively propose all potential tracklets and select the one that is best matched with language expression as output.", + "bbox": [ + 75, + 395, + 467, + 606 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "- Unsupervised VOS. It is also known as automatic VOS or zero-shot VOS [24, 44, 54, 58, 61, 78, 83, 88, 100, 101]. Different from the above VOS settings, unsupervised VOS does not require any manual clues to indicate the objects but aims to automatically find the primary objects in a video. Unsupervised VOS can only deal with objects of pre-defined categories. Early methods usually use post-processing steps [24]. Then end-to-end training methods become the mainstream in unsupervised VOS, which can be categorized into local content encoding and contextual content encoding. The local content encoding methods [14, 33, 43, 44, 82, 83, 112] typically employ two parallel networks to extract features from optical flow and RGB image. The contextual content encoding methods [59, 60, 87] focus on capturing long-term global information.", + "bbox": [ + 75, + 607, + 467, + 834 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Related Video Segmentation Tasks", + "text_level": 1, + "bbox": [ + 76, + 845, + 377, + 861 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "There are some other video segmentation tasks that are related to video object segmentation, for example, video", + "bbox": [ + 76, + 869, + 467, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "instance segmentation, video semantic segmentation, and video panoptic segmentation.", + "bbox": [ + 498, + 90, + 890, + 119 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "- Video Instance Segmentation (VIS). Video instance segmentation is extended from image instance segmentation by Yang et al. [99], it simultaneously conducts detection, segmentation, and tracking of instances of predefined categories in videos. Thanks to the large-scale VIS dataset YouTube-VIS [99], a series of learning methods have been developed and greatly advanced the performance of VIS [36, 48]. Then, occluded video instance segmentation is proposed by [76] to study the video instance segmentation under occluded scenes. Similar to [76], we study video understanding under complex scenarios like occlusions, but different from [76], we focus on video object segmentation (VOS) and our proposed MOSE dataset contains more videos and more complex scenes than [76], especially in terms of object's disappearance-reappearance.", + "bbox": [ + 496, + 122, + 890, + 348 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "- Video Semantic Segmentation (VSS). Driven by the great success in image semantic segmentation [7, 57] and large-scale video semantic segmentation datasets [3,17,65], video semantic segmentation has drawn lots of attention and achieved significant achievement. Compared to image domain, temporal consistency and model efficiency are the new efforts in the video domain. For example, Sun et al. [80] propose Coarse-to-Fine Feature Mining (CFFM) to capture both static context and motional context.", + "bbox": [ + 496, + 349, + 890, + 484 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "- Video Panoptic Segmentation (VPS). Kim et al. [38] introduce panoptic segmentation to the video domain to simultaneously segment and track both the foreground instance objects and background stuff. They build a VPS dataset with 124 videos. Then, Miao et al. [64] build a larger VPS dataset called VIPSeg with 3,536 videos. Existing methods [77, 92] mainly add temporal refinement or cross-frame association modules upon image panoptic segmentation models to enhance temporal conformity and instance tracking performance.", + "bbox": [ + 496, + 486, + 890, + 636 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.3. Complex Scene Understanding", + "text_level": 1, + "bbox": [ + 498, + 648, + 772, + 666 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Complex scene understanding has become a research focus in the image understanding domain [15, 18, 39, 41, 47, 63, 90, 108, 110]. For example, Ke et al. [37] propose Bilayer Convolutional Network (BCNet) to decouple overlapping objects into occluder and occludee layers. Zhang et al. [108] propose a self-supervised approach to conduct de-occlusion by ordering recovery, amodal completion, and content completion. On the video domain, however, occlusion understanding is still underexplored with only several multi-object tracking works [16, 55, 96, 113]. For example, Chu et al. [16] propose a spatial temporal attention mechanism (STAM) to capture the visible parts of targets and deal with the drift brought by occlusion. Zhu et al. [113] propose dual matching attention networks (DMAN) to deal with the noisy occlusions in multi-object tracking. Li et al. [46] propose", + "bbox": [ + 496, + 674, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "20226", + "bbox": [ + 478, + 944, + 519, + 955 + ], + "page_idx": 2 + }, + { + "type": "table", + "img_path": "images/3e85147504538580a3ca48f34f0f5b59211dbbae8e7cadc8cd0f5cccd64060e3.jpg", + "table_caption": [ + "Table 1. A complete list of object categories and their #instances in the MOSE dataset. The object categories are sorted in descending order of their frequency of occurrence." + ], + "table_footnote": [], + "table_body": "
CategoryNo.CategoryNo.CategoryNo.CategoryNo.
Person-other519Monkey181Bicycle130Boat73
Fish343Dog175Cyclist116Lizard68
Horse272Boat166Tiger108Duck64
Sheep264Sedan160Giraffe108Goose54
Zebra254Motorcyclist153Panda106Horse-rider46
Rabbit237Turtle142Driver90Bus29
Bird226Cat139Airplane89Truck15
Elephant207Parrot139Chicken86Vehicle-other14
Motorcycle192Cow139Bear84Poultry-other12
", + "bbox": [ + 78, + 142, + 468, + 311 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "to track every thing in the open world by performing class-agnostic association. In this work, we build a Complex Video Object Segmentation dataset to support future work on complex scene understanding in VOS.", + "bbox": [ + 75, + 339, + 468, + 400 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3. MOSE Dataset", + "text_level": 1, + "bbox": [ + 76, + 415, + 228, + 431 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In this section, we introduce the newly built MOSE dataset. We first present the video collection and annotation process in Section 3.1 and then give the dataset statistics and analysis in Section 3.2. Finally, we give the evaluation metrics in Section 3.3.", + "bbox": [ + 75, + 441, + 468, + 517 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.1. Video Collection and Annotation", + "text_level": 1, + "bbox": [ + 76, + 529, + 366, + 544 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Video Collection. The videos in MOSE are obtained from two sources. The first source is inherited from the OVIS dataset [76], which was designed for video instance segmentation. The second source consists of newly captured videos from real-world scenarios. We chose to include videos from the OVIS dataset because they contain numerous heavy occlusions and meet the requirements of complex scenes. However, for videos inherited from OVIS, since many objects appear for the first time after the first frame, they cannot be directly used for video object segmentation, which requires a first-frame reference. One solution would be to discard all objects that do not appear in the first frame, but this would result in a significant waste of mask annotations. To make full use of OVIS videos and adapt them for video object segmentation tasks, we cut each of these videos into several videos according to the frame where each object first appears in the videos. We then discard videos that do not meet our requirements. For the newly captured videos, we first select a set of semantic categories that are common in the real world, including vehicles (e.g., bicycle, bus, airplane, boat), animals (e.g., bird, panda, dog, giraffe), and human beings in different activities (e.g., motorcycling, driving, riding, running), and", + "bbox": [ + 75, + 551, + 470, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "then collect/film videos containing these categories from the campus, zoo, indoor, city street, etc. A complete list of object categories in the MOSE dataset can be seen in Table 1. These categories are common in our daily lives, where crowds and occlusions frequently occur. Moreover, they are included in popular large-scale image segmentation datasets such as MS-COCO [52], which makes it easy to use image-pretrained models.", + "bbox": [ + 496, + 90, + 890, + 210 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Our primary concern is video object segmentation under complex scenes that contain crowds, occlusion, multi-scale objects, and other challenging scenarios. Therefore, we established several rules to ensure that complex environments are included when collecting/shooting videos:", + "bbox": [ + 496, + 212, + 890, + 287 + ], + "page_idx": 3 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "R1. Each video must contain several objects, while videos with only a single object are excluded. Specifically, videos with crowded objects of similar appearance are highly valued.", + "R2. Occlusions should be present in the video. Videos that do not have any occlusions throughout the entirety of the frames are discarded. We encourage occlusions caused by other moving objects.", + "R3. Great emphasis should be placed on scenarios where objects disappear and then reappear due to occlusions or crowding.", + "R4. The target objects should be of a variety of scales and types, such as small-scale or large-scale, conspicuous or inconspicuous.", + "R5. Objects in the video must show sufficient motion. Videos with completely still objects or very little motion are discarded." + ], + "bbox": [ + 501, + 297, + 890, + 584 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Besides the rules mentioned above, we also require the video quality to be of high standard, which means the video resolution should be $1920 \\times 1080$ and the video length should be between 5 to 60 seconds in general.", + "bbox": [ + 496, + 595, + 890, + 656 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Video Annotation. Having all videos for MOSE been collected, our research team looks through them and figure out a set of targets-of-interest for each of the videos. Then we slightly clip the start and the end of videos, to reduce the number of less motional or simple frames in the video. Next we annotate the first-frame mask of the target objects, as VOS input. Following this, the videos are sent to the annotation team along with the first-frame masks for annotation of the subsequent video frames.", + "bbox": [ + 496, + 672, + 890, + 809 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Using the given first-frame mask as a reference, the annotation team is required to identify the target object in the given first-frame mask, then track and annotate the segmentation mask of the target object in all frames following the first frame. The process of annotating videos has been made easier with the help of an interactive annotation tool", + "bbox": [ + 496, + 810, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "20227", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 3 + }, + { + "type": "table", + "img_path": "images/7f059f34554895f239b703d23f8225fb1879ae955b3809aa2f8fe88b922a2ba5.jpg", + "table_caption": [ + "Table 2. Scale comparison between MOSE and existing VOS datasets. \"Annotations\" denotes the number of annotated object masks. \"Duration\" denotes the total duration (in minutes) of the annotated videos. \"mBOR\" denotes the mean of the Bounding-box-Occlusion Rate. \"Disapp. Rate\" represents the frequency of objects that disappear in at least one frame. The newly built MOSE has the longest video duration and the largest number of annotations. More importantly, the most notable feature of MOSE is that it contains lots of crowds, occlusions, and disappearance-reappearance objects, which provide much more complex scenarios for video object segmentation." + ], + "table_footnote": [], + "table_body": "
DatasetYearVideosCategoriesObjectsAnnotationsDurationmBORDisapp. Rate
YouTube-Objects [75]20129610961,6929.01--
SegTrack-v2 [42]20131411241,4750.590.128.3%
FBMS [67]201459161391,4657.700.0111.2%
JumpCut [23]20152214226,3313.5200%
DAVIS16 [73]201650-503,4402.88--
DAVIS17 [74]201790-20513,5435.170.0316.1%
YouTube-VOS [97]20184,453947,755197,272334.810.0513.0%
MOSE (ours)20232,149365,200431,725443.620.2341.5%
", + "bbox": [ + 88, + 164, + 883, + 320 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "that we developed. The annotation tool automatically loads videos and all target objects. Annotators use the tool to load and preview videos and first-frame masks, annotate and visualize the segmentation masks in the subsequent frames, and save them. The annotation tool also has a built-in interactive object segmentation network XMem [10], to assist annotations in producing high-quality masks. To ensure the annotation quality under complex scenes, the annotators are required to clearly track the object that disappears and reappears due to heavy occlusions and crowd. For frames in which the target object is disappeared or is fully occluded, annotators also need to confirm that the output masks of such frames shall be blank. It is a requirement that all of our videos be annotated every five frames at the very least. For the purpose of testing the frame-rate robustness of the models, some videos are annotated every frame.", + "bbox": [ + 75, + 356, + 472, + 598 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "After annotation, the videos are reviewed by our verification team to ensure high-quality annotations, particularly for videos containing occlusions, crowds, or instances of objects disappearing and reappearing.", + "bbox": [ + 75, + 598, + 470, + 659 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.2. Dataset Statistics", + "text_level": 1, + "bbox": [ + 76, + 666, + 246, + 681 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In Table 2, we analyze the data statistics of the new MOSE dataset using previous datasets for the video object segmentation as a reference for the analysis, including JumpCut [23], SegTrack-v2 [42], YouTube-Objects [75], FBMS [67], DAVIS [73, 74], and YouTube-VOS [97]. As shown in Table 2, there are 2,149 videos and 431,725 mask annotations for 5,200 objects contained in the proposed MOSE dataset. Comparing with previous largest VOS dataset YouTube-VOS [97], MOSE has much more mask annotations, $431\\mathrm{k}$ vs. $197\\mathrm{k}$ . Among the 8 video object segmentation datasets that we analyzed in Table 2, MOSE has the longest video duration (433.62 minutes), which is about 100 minutes longer than the second longest dataset YouTube-VOS (334.81 minutes) and is hundreds of times", + "bbox": [ + 75, + 688, + 472, + 900 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/cf719d2be994670c6bd4f8ce76077392104b0f7ca93abf561c55a34e53fcaaf0.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 501, + 354, + 645, + 416 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/fe0ee5e59a74916260329a7befe1b3c8d152ce65b64488467dcc8097ba335a9d.jpg", + "image_caption": [ + "Low occlusion but high BOR" + ], + "image_footnote": [], + "bbox": [ + 645, + 354, + 787, + 417 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/bbc3333603268f471306c414391e211cd8c05f242b8e13cfabb75f9077a4f9bd.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 789, + 354, + 885, + 417 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/7f6aba10aaf15cf0f68b780ee0202d4276a920de7b692b327e0ee9a307acc236.jpg", + "image_caption": [ + "High occlusion but low BOR", + "Figure 2. Failure cases of the BOR indicator. It can be seen from the first row of samples that they have high BOR values, but there is less or no occlusion present. Samples in the second row have very small BOR values, but there are severe occlusions in the samples." + ], + "image_footnote": [], + "bbox": [ + 503, + 431, + 645, + 494 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/ca063f5210322ecc9e81080ac587d6cb62633bf61ee96ff7971c07de5dd16be1.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 645, + 431, + 789, + 494 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/38cc128101990d559111c3c1be0d8ba1af0a7af048835e019606d501b4bb0e85.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 790, + 431, + 885, + 494 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "longer than the other seven datasets. We include more long videos in the MOSE compared to previous VOS datasets to ensure that our dataset contains a diverse range of occlusion scenarios, motion scenarios, and instances of objects disappearing and reappearing.", + "bbox": [ + 498, + 604, + 893, + 681 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Disappearance and Occlusion Analysis. Previous occluded video datasets OVIS [76] defines a Bounding-box Occlusion Rate (BOR) to reflect the occlusion degree. The BOR is calculated by the Intersection-over-Union of bounding boxes in the videos. We provide the mean of BOR of all frames in Table 2. The MOSE has the largest value of mBOR, indicating the more frequency of occlusions in MOSE than previous datasets. However, we find that BOR can only roughly reflect the occlusion. It does not well reveal the degree of occlusion in the MOSE dataset and may be prone to making some mistakes in this regard. As shown in the first row of Figure 2, high BOR is observed in the three images with low occlusion or even no occlusion. In", + "bbox": [ + 496, + 704, + 893, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "20228", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "contrast, in the images of the second row, where there are heavily occluded objects, the BOR is low and even 0.", + "bbox": [ + 75, + 90, + 468, + 119 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Therefore, besides counting BOR, we further calculate the number of disappeared objects that disappear in at least one frame of the video, followed by the disappearance rate that reflects the frequency of disappearances, which illustrates how often the disappearance of objects occurs due to complex scenarios in a dataset. As shown in Table 2, the disappearance rate (Disapp. Rate) of MOSE stands at the highest, reaching $41.5\\%$ . Meanwhile, a total of $27.0\\%$ of objects in MOSE showcase the disappearance-reappearance phenomenon, meaning they completely vanish and subsequently reappear in future frames. These observations underscore the frequent and substantial occurrence of disappearance and occlusions in the proposed MOSE dataset.", + "bbox": [ + 75, + 121, + 470, + 316 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "3.3. Evaluation Metrics", + "text_level": 1, + "bbox": [ + 76, + 335, + 261, + 351 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In accordance with the previous method [73, 74], we compute the region similarity $\\mathcal{J}$ and the contour accuracy $\\mathcal{F}$ as evaluation metrics. Given segmentation mask predictions $\\hat{M} \\in \\{0,1\\}^{H\\times W}$ and the ground-truth masks $M \\in \\{0,1\\}^{H\\times W}$ , region similarity $\\mathcal{J}$ is obtained by calculating the Intersection-over-Union (IoU) of $\\hat{M}$ and $M$ ,", + "bbox": [ + 76, + 359, + 468, + 450 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {J} = \\frac {\\hat {M} \\cap M}{\\hat {M} \\cup M}. \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 225, + 459, + 468, + 489 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Then, the average region similarity $J_{mean}$ over all objects is calculated as the final region similarity result. We use $J$ to represent $J_{mean}$ for the sake of brevity. To measure the contour quality of $\\hat{M}$ , contour recall $\\mathbf{R}_c$ and precision $\\mathrm{P}_c$ are calculated via bipartite graph matching [62]. Then, the contour accuracy $F$ is the harmonic mean of the contour recall $\\mathbf{R}_c$ and precision $\\mathrm{P}_c$ , i.e.,", + "bbox": [ + 75, + 492, + 468, + 599 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {F} = \\frac {2 \\mathrm {P} _ {c} \\mathrm {R} _ {c}}{\\mathrm {P} _ {c} + \\mathrm {R} _ {c}}, \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 228, + 604, + 468, + 638 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "which represents how closely the contours of predicted masks resemble the contours of ground-truth masks. The average contour accuracy $\\mathcal{F}_{mean}$ over all objects is calculated as the final contour accuracy result. We use $\\mathcal{F}$ to represent $\\mathcal{F}_{mean}$ for the sake of brevity. Then, $J\\& F = (J + F) / 2$ is used to measure the overall performance.", + "bbox": [ + 75, + 643, + 468, + 734 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 747, + 209, + 763 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Herein we conduct experiments and benchmarks on four different Video Object Segmentation (VOS) settings, including semi-supervised (or one-shot) VOS with mask-initialization, semi-supervised VOS with box-initialization, unsupervised (or zero-shot) VOS, and interactive VOS, to comprehensively analyze the newly built MOSE dataset.", + "bbox": [ + 75, + 772, + 468, + 863 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Implementation Details. The proposed MOSE dataset is consistent with the YouTube-VOS [97] format. We replace", + "bbox": [ + 75, + 869, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/791580b87a82ee408dc73efe4120664c984984dad3566b71a6244a3ddd2aeb28.jpg", + "table_caption": [ + "Table 3. Comparisons of state-of-the-art semi-supervised methods on the validation set. “ $\\mathcal{J}$ ” and “ $\\mathcal{F}$ ” denote the mean of region similarity and the mean of contour accuracy. $\\mathcal{J} \\& \\mathcal{F}$ denotes the mean of $\\mathcal{J}$ and $\\mathcal{F}$ . BL30K [11] is not added during the training stage to make a fair comparison." + ], + "table_footnote": [], + "table_body": "
MethodPub.MOSE (ours)DAVIS17YT-VOS18
JFJ&FJ&FG
AOT [103]NeurIPS'2153.161.357.284.984.1
STCN [12]NeurIPS'2146.655.050.885.483.0
RDE [45]CVPR'2244.652.948.884.2-
SWEM [53]CVPR'2246.854.950.984.382.8
XMem [10]ECCV'2253.362.057.686.285.7
DeAOT [104]NeurIPS'2255.163.859.485.286.0
", + "bbox": [ + 506, + 162, + 885, + 297 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "the training dataset of previous methods from YouTube-VOS with our MOSE and strictly follow their training settings on YouTube-VOS [97]. We follow DAVIS [73, 74] to evaluate the performance and report the results of $\\mathcal{J}_{\\text{mean}}$ , $\\mathcal{F}_{\\text{mean}}$ , and $\\mathcal{J} \\& \\mathcal{F}$ on the validation set of MOSE. During the training of these VOS methods, we follow their way of using image pre-trained models but do not use any additional video datasets for pretraining.", + "bbox": [ + 496, + 323, + 890, + 445 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Settings. There are 2,149 videos in the whole MOSE dataset. These videos are split into 1,507 training videos, 311 validation videos, and 331 testing videos, for model training, daily evaluation, and competition period evaluation, respectively. Each of the videos gives a first-frame mask or bounding box as the reference of the target object for the semi-supervised (one-shot) VOS setting, and first-frame scribbles for the interactive VOS setting.", + "bbox": [ + 496, + 454, + 890, + 575 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Semi-supervised Video Object Segmentation", + "text_level": 1, + "bbox": [ + 498, + 585, + 877, + 603 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Semi-supervised video object segmentation, or one-shot video object segmentation, gives either the first frame mask or bounding box of the target object as a clue and reference. We train and evaluate the very recent 6 mask-initialization semi-supervised VOS methods and 2 box-initialization semi-supervised VOS methods built upon ResNet-50 [26] on the MOSE dataset, as shown in Table 3 and Table 4, respectively. It is our hope that the experiments will provide baselines for future semi-supervised VOS algorithms to be developed.", + "bbox": [ + 496, + 609, + 890, + 760 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Mask-initialization. This setting is a classic and currently the most popular topic for video object segmentation. A lot of excellent deep-learning-based works have been developed for this setting in the past decade and greatly improve the video object segmentation performance to a saturation level. For example, the most recent state-of-the-art method DeAOT [104] achieves $85.2\\%$ $\\mathcal{J}\\& \\mathcal{F}$ on the DAVIS 2017 [74], $86.0\\%$ $\\mathcal{G}$ on YouTube-VOS [97], and $92.3\\%$ $\\mathcal{J}\\& \\mathcal{F}$ on DAVIS 2016 [73], which are excellent", + "bbox": [ + 496, + 763, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "20229", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/996cce833b94523a5ab290616fb2d204b135f5c873a3a88bb6aa73d69d1f0137.jpg", + "table_caption": [ + "Table 4. Comparisons of state-of-the-art box-initialization semi-supervised methods on the validation set. \"J\" and \"F\" denote the mean of region similarity and the mean of contour accuracy. J&F denotes the mean of $\\mathcal{I}$ and $\\mathcal{F}$ ." + ], + "table_footnote": [], + "table_body": "
MethodPub.MOSE (ours)DAVIS17YT-VOS18
JFJ&FJ&FG
SiamMask [86]CVPR'1917.326.722.056.452.8
FTMU [81]CVPR'2019.128.523.870.6-
", + "bbox": [ + 78, + 148, + 468, + 210 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "performance and almost reach the ground truth. To analyze the newly built MOSE dataset and test the performance of existing methods in complex scenes, we train and evaluate these methods on MOSE. We report the results of 6 recent state-of-the-art methods on the validation set of MOSE, including AOT [103], STCN [12], RDE [45], SWEM [53], XMem [10], and DeAOT [104], as shown in Table 3. Current state-of-the-art methods only achieve the performance from $48.8\\%$ $\\mathcal{J}\\& \\mathcal{F}$ to $59.4\\%$ $\\mathcal{J}\\& \\mathcal{F}$ on the validation set of the newly proposed MOSE dataset, while their results on DAVIS 2017 [74] and YouTube-VOS [97] are usually above $80\\%$ $\\mathcal{J}\\& \\mathcal{F}$ or $\\mathcal{G}$ , some of them almost reach $90\\%$ $\\mathcal{J}\\& \\mathcal{F}$ or $\\mathcal{G}$ on DAVIS 2017 and YouTube-VOS. The results reveal that although we have achieved excellent VOS performance on previous benchmarks, there are unresolved challenges under complex scenes and more efforts are desired to explore these challenges in the future. Discussion about the MOSE dataset and some potential future directions are provided in Section 5.", + "bbox": [ + 75, + 226, + 472, + 513 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Box-initialization. As shown in Table 4, two semi-supervised (one-shot) VOS methods with a bounding box as the first-frame reference are trained on MOSE and evaluated on the validation set of MOSE, including SimMask [86] and FTMU [81]. Current state-of-the-art methods achieve only $22.0\\%$ and $23.8\\%$ $\\mathcal{J}\\& \\mathcal{F}$ on the validation set of the newly proposed MOSE dataset, while their results on DAVIS 2017 [74] are already $70 + \\%$ $\\mathcal{J}\\& \\mathcal{F}$ .", + "bbox": [ + 75, + 518, + 468, + 638 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "After careful analysis, we believe that one of the reasons for such a significant drop in performance is that there are many heavy occlusions, small-scale objects, and crowded scenarios in the videos of MOSE dataset, which make the weakly supervised segmentation of the videos much more difficult. There is a possibility that, even within the target bounding box region, the target object may not the most salient one due to heavy occlusions and crowd. The occlusion of an object can cause it to be broken up into several pieces that are not adjacent to each other, which greatly increases the difficulty of segmenting an object using a box-driven approach.", + "bbox": [ + 75, + 638, + 470, + 821 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.2. Unsupervised Video Object Segmentation", + "text_level": 1, + "bbox": [ + 76, + 830, + 431, + 848 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Unsupervised video object segmentation, or zero-shot video object segmentation, does not require any manual clues (e.g., mask or bounding box) as a reference to indicate", + "bbox": [ + 76, + 854, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/efde568ae431f3a9054f721b91447691b323abbc6a7a5e4cc78f63b1ea910bea.jpg", + "table_caption": [ + "Table 5. Comparisons of state-of-the-art multi-object zero-shot VOS methods on the validation set. \"J\" and \"F\" denote the mean of region similarity and the mean of contour accuracy. J&F denotes the mean of $\\mathcal{I}$ and $\\mathcal{F}$ ." + ], + "table_footnote": [], + "table_body": "
MethodPub.MOSE (ours)DAVIS17
JFJ&FJ&F
RVOS [84]CVPR'1924.136.930.543.7
AGNN [87]ICCV'1938.648.843.761.1
STEm-Seg [1]ECCV'2043.350.546.964.7
", + "bbox": [ + 508, + 148, + 885, + 226 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/8421815f2d49c00752686d60b3ace9e08678ce41e840924b094708530d1e92c1.jpg", + "table_caption": [ + "Table 6. Comparisons of state-of-the-art interactive VOS methods on the validation set. $J \\& F @60s$ denotes the $J \\& F$ performance reached by methods within 60 seconds interactions." + ], + "table_footnote": [], + "table_body": "
MethodPub.MOSE (ours) J&F@60sDAVIS17 J&F@60s
IPNet [68]CVPR'1941.278.7
STM [70]ICCV'1945.384.8
MANet [66]CVPR'2043.679.5
ATNet [27]ECCV'2044.582.7
GIS [28]CVPR'2150.286.6
MiVOS [11]CVPR'2151.488.5
STCN [12]NeurIPS'2156.888.8
", + "bbox": [ + 501, + 286, + 888, + 420 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "the objects but aims to find the primary objects in a video automatically. The mainstream of zero-shot VOS methods focuses on addressing single-object VOS. However, MOSE is a multi-object VOS dataset like DAVIS 2017 [74], thus we only benchmark multi-object zero-shot VOS methods on MOSE, e.g., STEm-Seg [1], AGNN [87], and RVOS [84]. The results are shown in Table 5. In this setting, only videos with exhaustive first-frame annotations are used. Existing methods rely on off-the-shelf image-trained instance segmentation methods, which can well detect/segment objects in the static image thanks to complex scene learning in the image domain. The performance drop is mainly due to temporal challenges.", + "bbox": [ + 496, + 439, + 890, + 638 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Interactive Video Object Segmentation", + "text_level": 1, + "bbox": [ + 498, + 648, + 834, + 666 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Following the interactive track of DAVIS 2019 Challenge [5], we provide initial scribbles for the target object in a specific video sequence, which are used as the first interaction. The interactive video object segmentation methods are required to predict the segmentation mask for the whole video based on the first interaction. Then, by comparing predicted masks and ground truth masks across the video, corrective scribbles on the worst frame are further provided for the methods to refine the video segmentation prediction. The above step is allowed to be repeated up to 8 times with a time limitation of 30s for each object. We report the metric of $J \\& F$ @60s to encourage the methods to have a good balance between speed and accuracy. As shown in Table 6, seven recent interactive video object segmentation methods are evaluated on the validation set of MOSE.", + "bbox": [ + 496, + 672, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "20230", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5. Discussion and Future Directions", + "text_level": 1, + "bbox": [ + 76, + 89, + 379, + 106 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Herein we discuss the challenges of the proposed MOSE dataset brought by complex scenes and provide some potential future directions based on the experimental results analysis of the existing methods on MOSE.", + "bbox": [ + 76, + 114, + 468, + 175 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "- Stronger Association to Track Reappearing Objects. It is necessary to develop stronger association/re-identification algorithms for VOS methods in order to be able to track objects that disappear and then reappear. Especially, the most interesting thing is that we have noticed that a number of disappeared-then-reappeared objects have been reappearing with a different appearance from the time they disappeared, i.e., appearance-changing objects. For example, the target player in Figure 1 shows his back before disappearing while showing the front at reappearing. There is a great deal of difficulty in tracking with such an appearance change.", + "bbox": [ + 75, + 179, + 468, + 345 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "- Video Object Segmentation of Occluded Objects. The frequent occlusions in the videos of MOSE provide data support to the research of occlusion video understanding. Tracking and segmenting an object with heavy occlusion have rarely been studied since the target objects in existing datasets are usually salient and dominant. In real-world scenarios, isolated objects rarely appear while occluded scenes occur frequently. Our human beings can well capture those occluded objects, thanks to our contextual association and reasoning ability. With the introduction of an understanding of occlusion into the process of video object segmentation, the VOS methods will become more practical for use in real-world applications. Especially, the occlusions make the box-initialization semi-supervised VOS setting more challenging in terms of segmenting an occluded object by bounding box.", + "bbox": [ + 75, + 348, + 468, + 590 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "- Attention on Small & Inconspicuous Objects. Although the detection and segmentation of small objects is a hot topic in the image domain, tracking and segmenting small and inconspicuous objects in the video object segmentation domain is still to be developed. As a matter of fact, most of the existing video object segmentation methods mainly focus on tracking large and salient objects. The lack of sufficient attention to small-scale objects makes the video object segmentation methods less pronounced in practical applications that may involve target objects of varying sizes and types. There are many objects in the proposed MOSE dataset that are on a small scale and are inconspicuous in the videos, which provides a greater opportunity for the research of tracking and segmenting objects that are small and inconspicuous in realistic scenarios.", + "bbox": [ + 75, + 595, + 468, + 820 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "- Tracking Objects in Crowd. One of the most notable features of the MOSE is crowded scenarios, which are common in real-world applications. There are many videos in the MOSE dataset, which contain crowd objects, such as flocks of sheep moving together, groups of cyclists racing,", + "bbox": [ + 75, + 824, + 468, + 901 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "pedestrians moving on a crowded street, and etc. A scenario like this presents challenges when it comes to segmenting and tracking one object among a crowd of objects that share a similar appearance and motion to the target object with the crowd as a whole. In the image/frame domain, it is desired for video object segmentation algorithms to enhance the identification ability to distinguish between different objects with a similar appearance. What's more, in the temporal domain, it is challenging to perform the object association between the two frames with the crowd consisting of similar-looking objects.", + "bbox": [ + 496, + 90, + 890, + 257 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "- Long-Term Video Segmentation: In terms of practical applications like movie editing and surveillance monitoring, long-term video understanding is much more practical than short-term video understanding. For example, the average length of videos on YouTube is around twelve minutes, which is much longer than the average length of the existing video object segmentation dataset. Although existing VOS methods provide excellent performance, they typically require a lot of computing resources, e.g., GPU memory, for storing the object features of previous frames. Due to the large computation cost, most existing VOS methods cannot well handle long videos. The average video length of the MOSE dataset is longer than existing VOS datasets, bringing more challenges and opportunities in dealing with long-term videos. It is a good and practical direction to design VOS algorithms that can deal with long videos with low computation costs while achieving high-quality segmentation results.", + "bbox": [ + 496, + 262, + 890, + 534 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 556, + 617, + 571 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We build a large-scale video object segmentation dataset named MOSE to revisit and support the research of video object segmentation under complex scenes. There are 2,149 high-resolution videos in MOSE with 431,725 high-quality object masks for 5,200 objects from 36 categories. The videos in MOSE are commonly long enough to ensure diverse and sufficient occlusion, motion, and disappearance-reappearance scenarios. Based on the proposed MOSE dataset, we benchmark existing VOS methods and conduct a comprehensive comparison. We train and evaluate six methods under the semi-supervised (one-shot) setting with a mask as the first-frame reference, two methods with a bounding box as the first-frame reference, three methods under the unsupervised (zero-shot) setting, and seven methods under the interactive setting. After evaluating existing VOS methods on MOSE dataset and comprehensively analyzing the results, some challenges and potential directions for future VOS research are concluded. We find that we are still at a nascent stage of segmenting and tracking objects in complex scenes where crowds, disappearing, occlusions, and inconspicuous/small objects occur frequently.", + "bbox": [ + 496, + 583, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "20231", + "bbox": [ + 478, + 945, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 90, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Ali Athar, Sabarinath Mahadevan, Aljosa Osep, Laura Leal-Taixe, and Bastian Leibe. Stem-seg: Spatio-temporal embeddings for instance segmentation in videos. In ECCV, 2020. 7", + "[2] Adam Botach, Evgenii Zheltonozhskii, and Chaim Baskin. End-to-end referring video object segmentation with multimodal transformers. In CVPR, 2022. 3", + "[3] Gabriel J Brostow, Julien Fauqueur, and Roberto Cipolla. Semantic object classes in video: A high-definition ground truth database. Pattern Recognition Letters, 30(2), 2009. 3", + "[4] Sergi Caelles, Kevis-Kokitsi Maninis, Jordi Pont-Tuset, Laura Leal-Taixe, Daniel Cremers, and Luc Van Gool. One-shot video object segmentation. In CVPR, 2017. 1, 2", + "[5] Sergi Caelles, Jordi Pont-Tuset, Federico Perazzi, Alberto Montes, Kevis-Kokitsi Maninis, and Luc Van Gool. The 2019 davis challenge on vos: Unsupervised multi-object segmentation. arXiv:1905.00737, 2019. 7", + "[6] Bowen Chen, Huan Ling, Xiaohui Zeng, Gao Jun, Ziyue Xu, and Sanja Fidler. Scribblebox: Interactive annotation framework for video object segmentation. In ECCV, 2020. 3", + "[7] Liang-Chieh Chen, George Papandreou, Iasonas Kokkinos, Kevin Murphy, and Alan L Yuille. Deep convolution with deep convolutional nets, atrous convolution, and fully connected crfs. IEEE TPAMI, 40(4), 2017. 3", + "[8] Xi Chen, Zuoxin Li, Ye Yuan, Gang Yu, Jianxin Shen, and Donglian Qi. State-aware tracker for real-time video object segmentation. In CVPR, 2020. 2", + "[9] Yuhua Chen, Jordi Pont-Tuset, Alberto Montes, and Luc Van Gool. Blazingly fast video object segmentation with pixel-wise metric learning. In CVPR, 2018. 2, 3", + "[10] Ho Kei Cheng and Alexander G Schwing. Xmem: Long-term video object segmentation with an atkinson-shiffrin memory model. In ECCV. Springer, 2022. 2, 5, 6, 7", + "[11] Ho Kei Cheng, Yu-Wing Tai, and Chi-Keung Tang. Modular interactive video object segmentation: Interaction-to-mask, propagation and difference-aware fusion. In CVPR, 2021. 3, 6, 7", + "[12] Ho Kei Cheng, Yu-Wing Tai, and Chi-Keung Tang. Rethinking space-time networks with improved memory coverage for efficient video object segmentation. In NeurIPS, 2021. 6, 7", + "[13] Jingchun Cheng, Yi-Hsuan Tsai, Wei-Chih Hung, Shengjin Wang, and Ming-Hsuan Yang. Fast and accurate online video object segmentation via tracking parts. In CVPR, 2018. 2, 3", + "[14] Jingchun Cheng, Yi-Hsuan Tsai, Shengjin Wang, and Ming-Hsuan Yang. Segflow: Joint learning for video object segmentation and optical flow. In ICCV, 2017. 1, 3", + "[15] Meng-Jiun Chiou, Henghui Ding, Hanshu Yan, Changhu Wang, Roger Zimmermann, and Jiashi Feng. Recovering the unbiased scene graphs from the biased ones. In ACM MM, 2021. 3", + "[16] Qi Chu, Wanli Ouyang, Hongsheng Li, Xiaogang Wang, Bin Liu, and Nenghai Yu. Online multi-object tracking using cnn-based single object tracker with spatial-temporal attention mechanism. In ICCV, 2017. 3", + "[17] Marius Cordts, Mohamed Omran, Sebastian Ramos, Timo Rehfeld, Markus Enzweiler, Rodrigo Benenson, Uwe Franke, Stefan Roth, and Bernt Schiele. The cityscapes dataset for semantic urban scene understanding. In CVPR, 2016. 3", + "[18] Henghui Ding, Xudong Jiang, Bing Shuai, Ai Qun Liu, and Gang Wang. Semantic segmentation with context encoding and multi-path decoding. IEEE TIP, 29, 2020. 3", + "[19] Henghui Ding, Chang Liu, Shuting He, Xudong Jiang, and Chen Change Loy. MeViS: A large-scale benchmark for video segmentation with motion expressions. In ICCV, 2023. 3", + "[20] Henghui Ding, Chang Liu, Suchen Wang, and Xudong Jiang. VLT: Vision-language transformer and query generation for referring segmentation. IEEE TPAMI, 2023. 3" + ], + "bbox": [ + 86, + 114, + 468, + 898 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[21] Kevin Duarte, Yogesh S. Rawat, and Mubarak Shah. Capsulevos: Semi-supervised video object segmentation using capsule routing. In ICCV, 2019. 2", + "[22] Brendan Duke, Abdalla Ahmed, Christian Wolf, Parham Aarabi, and Graham W Taylor. Sstvos: Sparse spatiotemporal transformers for video object segmentation. In CVPR, 2021. 2", + "[23] Qingnan Fan, Fan Zhong, Dani Lischinski, Daniel Cohen-Or, and Baoquan Chen. JumpCut: non-successive mask transfer and interpolation for video cutout. ACM Tran. Graphics, 34(6), 2015. 5", + "[24] Katerina Fragkiadaki, Pablo Arbelaez, Panna Felsen, and Jitendra Malik. Learning to segment moving objects in videos. In CVPR, 2015. 3", + "[25] Junwei Han, Le Yang, Dingwen Zhang, Xiaojun Chang, and Xiaodan Liang. Reinforcement cutting-agent learning for video object segmentation. In CVPR, 2018. 2", + "[26] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, 2016. 6", + "[27] Yuk Heo, Yeong Jun Koh, and Chang-Su Kim. Interactive video object segmentation using global and local transfer modules. In ECCV, 2020. 7", + "[28] Yuk Heo, Yeong Jun Koh, and Chang-Su Kim. Guided interactive video object segmentation using reliability-based attention maps. In CVPR, 2021. 3, 7", + "[29] Li Hu, Peng Zhang, Bang Zhang, Pan Pan, Yinghui Xu, and Rong Jin. Learning position and target consistency for memory-based video object segmentation. In CVPR, 2021. 2", + "[30] Ping Hu, Gang Wang, Xiangfei Kong, Jason Kuen, and Yap-Peng Tan. Motion-guided cascaded refinement network for video object segmentation. In CVPR, 2018. 2", + "[31] Xuhua Huang, Jiarui Xu, Yu-Wing Tai, and Chi-Keung Tang. Fast video object segmentation with temporal aggregation network and dynamic template matching. In CVPR, 2020. 2", + "[32] Allan Jabri, Andrew Owens, and Alexei Efros. Space-time correspondence as a contrastive random walk. In NeurIPS, 2020. 2", + "[33] Suyog Dutt Jain, Bo Xiong, and Kristen Grauman. Fusionseg: Learning to combine motion and appearance for fully automatic segmentation of generic objects in videos. In CVPR, 2017. 1, 3", + "[34] Varun Jampani, Raghudeep Gadde, and Peter V. Gehler. Video propagation networks. In CVPR, 2017. 2", + "[35] Won-Dong Jang and Chang-Su Kim. Online video object segmentation via convolutional trident network. In CVPR, 2017. 2", + "[36] Lei Ke, Henghui Ding, Martin Danelljan, Yu-Wing Tai, Chi-Keung Tang, and Fisher Yu. Video mask transfiner for high-quality video instance segmentation. In ECCV. Springer, 2022. 3", + "[37] Lei Ke, Yu-Wing Tai, and Chi-Keung Tang. Deep occlusion-aware instance segmentation with overlapping bilayers. In CVPR, 2021. 3", + "[38] Dahun Kim, Sanghyun Woo, Joon-Young Lee, and In So Kweon. Video panoptic segmentation. In CVPR, 2020. 3", + "[39] Adam Kortylewski, Qing Liu, Angtian Wang, Yihong Sun, and Alan Yuille. Compositional convolutional neural networks: A robust and interpretable model for object recognition under occlusion. IJCV, 129(3), 2021. 3", + "[40] Zihang Lai, Erika Lu, and Weidi Xie. MAST: A memory-augmented self-supervised tracker. In CVPR, 2020. 2", + "[41] Justin Lazarow, Kwonjoon Lee, Kunyu Shi, and Zhuowen Tu. Learning instance occlusion for panoptic segmentation. In CVPR, 2020. 3", + "[42] Fuxin Li, Taeyoung Kim, Ahmad Humayun, David Tsai, and James M Rehg. Video segmentation by tracking many figure-ground segments. In ICCV, 2013. 5", + "[43] Guanbin Li, Yuan Xie, Tianhao Wei, Keze Wang, and Liang Lin. Flow guided recurrent neural encoder for video salient object detection. In CVPR, 2018. 3" + ], + "bbox": [ + 509, + 93, + 890, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "20232", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[44] Haofeng Li, Guanqi Chen, Guanbin Li, and Yizhou Yu. Motion guided attention for video salient object detection. In ICCV, 2019. 3", + "[45] Mingxing Li, Li Hu, Zhiwei Xiong, Bang Zhang, Pan Pan, and Dong Liu. Recurrent dynamic embedding for video object segmentation. In CVPR, 2022. 6, 7", + "[46] Siyuan Li, Martin Danelljan, Henghui Ding, Thomas E Huang, and Fisher Yu. Tracking every thing in the wild. In ECCV. Springer, 2022. 3", + "[47] Xiangtai Li, Henghui Ding, Wenwei Zhang, Haobo Yuan, Jiangmiao Pang, Guangliang Cheng, Kai Chen, Ziwei Liu, and Chen Change Loy. Transformer-based visual segmentation: A survey. arXiv preprint arXiv:2304.09854, 2023. 3", + "[48] Xiangtai Li, Hao He, Yibo Yang, Henghui Ding, Kuiyuan Yang, Guangliang Cheng, Yunhai Tong, and Dacheng Tao. Improving video instance segmentation via temporal pyramid routing. IEEE TPAMI, 2022. 3", + "[49] Chen Liang, Yu Wu, Tianfei Zhou, Wenguan Wang, Zongxin Yang, Yunchao Wei, and Yi Yang. Rethinking cross-modal interaction from a top-down perspective for referring video object segmentation. arXiv preprint arXiv:2106.01061, 2021. 3", + "[50] Fanchao Lin, Hongtao Xie, Yan Li, and Yongdong Zhang. Query-memory re-aggregation for weakly-supervised video object segmentation. In AAAI, 2021. 3", + "[51] Huaijia Lin, Xiaojuan Qi, and Jiaya Jia. Agss-vos: Attention guided single-shot video object segmentation. In CVPR, 2019. 2", + "[52] Tsung-Yi Lin, Michael Maire, Serge J Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In ECCV, 2014. 4", + "[53] Zhihui Lin, Tianyu Yang, Maomao Li, Ziyu Wang, Chun Yuan, Wenhao Jiang, and Wei Liu. Swem: Towards real-time video object segmentation with sequential weighted expectation-maximization. In CVPR, 2022. 6, 7", + "[54] Daizong Liu, Dongdong Yu, Changhu Wang, and Pan Zhou. F2net: Learning to focus on the foreground for unsupervised video object segmentation. In AAAI, 2021. 3", + "[55] Qiankun Liu, Qi Chu, Bin Liu, and Nenghai Yu. Gsm: Graph similarity model for multi-object tracking. In IJCAI, 2020. 3", + "[56] Si Liu, Tianrui Hui, Shaofei Huang, Yunchao Wei, Bo Li, and Guanbin Li. Cross-modal progressive comprehension for referring segmentation. IEEE TPAMI, 2021. 3", + "[57] Jonathan Long, Evan Shelhamer, and Trevor Darrell. Fully convolutional networks for semantic segmentation. In CVPR, 2015. 3", + "[58] Xinkai Lu, Wenguan Wang, Martin Danelljan, Tianfei Zhou, Jianbing Shen, and Luc Van Gool. Video object segmentation with episodic graph memory networks. In ECCV, 2020. 3", + "[59] Xiankai Lu, Wenguan Wang, Chao Ma, Jianbing Shen, Ling Shao, and Fatih Porikli. See more, know more: Unsupervised video object segmentation with co-attention siamese networks. In CVPR, 2019. 3", + "[60] Xiankai Lu, Wenguan Wang, Jianbing Shen, David Crandall, and Luc Van Gool. Segmenting objects from relational visual data. IEEE TPAMI, 2021. 3", + "[61] Xiankai Lu, Wenguan Wang, Jianbing Shen, Yu-Wing Tai, David J Crandall, and Steven CH Hoi. Learning video object segmentation from unlabeled videos. In CVPR, 2020. 3", + "[62] David R Martin, Charless C Fowlkes, and Jitendra Malik. Learning to detect natural image boundaries using local brightness, color, and texture cues. IEEE TPAMI, 26(5), 2004. 6", + "[63] Bo Miao, Mohammed Bennamoun, Yongsheng Gao, and Ajmal Mian. Region aware video object segmentation with deep motion modeling. arXiv preprint arXiv:2207.10258, 2022. 3", + "[64] Jiaxu Miao, Xiaohan Wang, Yu Wu, Wei Li, Xu Zhang, Yunchao Wei, and Yi Yang. Large-scale video panoptic segmentation in the wild: A benchmark. In CVPR, 2022. 3" + ], + "bbox": [ + 84, + 93, + 467, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[65] Jiaxu Miao, Yunchao Wei, Yu Wu, Chen Liang, Guangrui Li, and Yi Yang. Vspw: A large-scale dataset for video scene parsing in the wild. In CVPR, 2021. 3", + "[66] Jiaxu Miao, Yunchao Wei, and Yi Yang. Memory aggregation networks for efficient interactive video object segmentation. In CVPR, 2020. 3, 7", + "[67] Peter Ochs, Jitendra Malik, and Thomas Brox. Segmentation of moving objects by long term video analysis. IEEE TPAMI, 36(6), 2014. 5", + "[68] Seoung Wug Oh, Joon-Young Lee, Ning Xu, and Seon Joo Kim. Fast user-guided video object segmentation by interaction-and-propagation networks. In CVPR, 2019. 2, 3, 7", + "[69] Seoung Wug Oh, Joon-Young Lee, Ning Xu, and Seon Joo Kim. Video object segmentation using space-time memory networks. In ICCV, 2019. 2", + "[70] Seoung Wug Oh, Joon Young Lee, Ning Xu, and Seon Joo Kim. Video object segmentation using space-time memory networks. In ICCV, 2019. 7", + "[71] Hyojin Park, Jayeon Yoo, Seohyeong Jeong, Ganesh Venkatesh, and Nojun Kwak. Learning dynamic network using a reuse gate function in semi-supervised video object segmentation. In CVPR, 2021. 1", + "[72] Federico Peruzzi, Anna Khoreva, Rodrigo Benenson, Bernt Schiele, and Alexander Sorkine-Hornung. Learning video object segmentation from static images. In CVPR, 2017. 2", + "[73] Federico Perazzi, Jordi Pont-Tuset, Brian McWilliams, Luc Van Gool, Markus Gross, and Alexander Sorkine-Hornung. A benchmark dataset and evaluation methodology for video object segmentation. In CVPR, 2016. 1, 2, 5, 6", + "[74] Jordi Pont-Tuset, Federico Perazzi, Sergi Caelles, Pablo Arbeláez, Alex Sorkine-Hornung, and Luc Van Gool. The 2017 davis challenge on video object segmentation. arXiv preprint arXiv:1704.00675, 2017. 1, 2, 5, 6, 7", + "[75] Alessandro Prest, Christian Leistner, Javier Civera, Cordelia Schmid, and Vittorio Ferrari. Learning object class detectors from weakly annotated video. In CVPR, 2012. 5", + "[76] Jiyang Qi, Yan Gao, Yao Hu, Xinggang Wang, Xiaoyu Liu, Xiang Bai, Serge Belongie, Alan Yuille, Philip HS Torr, and Song Bai. Occluded video instance segmentation: A benchmark. IJCV, 130(8), 2022. 3, 4, 5", + "[77] Siyuan Qiao, Yukun Zhu, Hartwig Adam, Alan Yuille, and Liang-Chieh Chen. Vip-deeplab: Learning visual perception with depth-aware video panoptic segmentation. In CVPR, 2021. 3", + "[78] Sucheng Ren, Wenxi Liu, Yongtuo Liu, Haoxin Chen, Guoqiang Han, and Shengfeng He. Reciprocal transformations for unsupervised video object segmentation. In CVPR, 2021. 3", + "[79] Seonguk Seo, Joon-Young Lee, and Bohyung Han. Urvos: Unified referring video object segmentation network with a large-scale benchmark. In ECCV, 2020. 3", + "[80] Guolei Sun, Yun Liu, Henghui Ding, Thomas Probst, and Luc Van Gool. Coarse-to-fine feature mining for video semantic segmentation. In CVPR, 2022. 3", + "[81] Mingjie Sun, Jimin Xiao, Eng Gee Lim, Bingfeng Zhang, and Yao Zhao. Fast template matching and update for video object tracking and segmentation. In CVPR, 2020. 3, 7", + "[82] Pavel Tokmakov, Karteek Alahari, and Cordelia Schmid. Learning video object segmentation with visual memory. In ICCV, 2017. 3", + "[83] Pavel Tokmakov, Cordelia Schmid, and Karteek Alahari. Learning to segment moving objects. IJCV, 127(3), 2019. 3", + "[84] Carles Ventura, Miriam Bellver, Andreu Girbau, Amaia Salvador, Ferran Marques, and Xavier Giro-i Nieto. Rvos: End-to-end recurrent network for video object segmentation. In CVPR, 2019. 7", + "[85] Paul Voigtlaender, Yuning Chai, Florian Schroff, Hartwig Adam, Bastian Leibe, and Liang-Chieh Chen. Feelvos: Fast end-to-end embedding learning for video object segmentation. In CVPR, 2019." + ], + "bbox": [ + 509, + 93, + 890, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "20233", + "bbox": [ + 478, + 945, + 517, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[86] Qiang Wang, Li Zhang, Luca Bertinetto, Weiming Hu, and Philip HS Torr. Fast online object tracking and segmentation: A unifying approach. In CVPR, 2019. 3, 7", + "[87] Wenguan Wang, Xiankai Lu, Jianbing Shen, David J Crandall, and Ling Shao. Zero-shot video object segmentation via attentive graph neural networks. In ICCV, 2019. 3, 7", + "[88] Wenguan Wang, Hongmei Song, Shuyang Zhao, Jianbing Shen, Sanyuan Zhao, Steven CH Ho, and Haibin Ling. Learning unsupervised video object segmentation through visual attention. In CVPR, 2019. 3", + "[89] Wenguan Wang, Tianfei Zhou, Fatih Porikli, David Crandall, and Luc Van Gool. A survey on deep learning technique for video segmentation. arXiv preprint arXiv:2107.01153, 2021. 2", + "[90] Xinlong Wang, Tete Xiao, Yuning Jiang, Shuai Shao, Jian Sun, and Chunhua Shen. Repulsion loss: Detecting pedestrians in a crowd. In CVPR, 2018. 3", + "[91] Ziqin Wang, Jun Xu, Li Liu, Fan Zhu, and Ling Shao. Ranet: Ranking attention network for fast video object segmentation. In ICCV, 2019. 2", + "[92] Sanghyun Woo, Dahun Kim, Joon-Young Lee, and In So Kweon. Learning to associate every segment for video panoptic segmentation. In CVPR, 2021. 3", + "[93] Dongming Wu, Xingping Dong, Ling Shao, and Jianbing Shen. Multi-level representation learning with semantic alignment for referring video object segmentation. In CVPR, 2022. 3", + "[94] Seoung Wug Oh, Joon-Young Lee, Kalyan Sunkavalli, and Seon Joo Kim. Fast video object segmentation by reference-guided mask propagation. In CVPR, 2018. 2", + "[95] Huaxin Xiao, Jiashi Feng, Guosheng Lin, Yu Liu, and Maojun Zhang. Monet: Deep motion exploitation for video object segmentation. In CVPR, 2018. 2", + "[96] Jiarui Xu, Yue Cao, Zheng Zhang, and Han Hu. Spatial-temporal relation networks for multi-object tracking. In ICCV, 2019. 3", + "[97] Ning Xu, Linjie Yang, Yuchen Fan, Jianchao Yang, Dingcheng Yue, Yuchen Liang, Brian Price, Scott Cohen, and Thomas Huang. Youtube-vos: Sequence-to-sequence video object segmentation. In ECCV, 2018. 1, 2, 5, 6, 7", + "[98] Shuangjie Xu, Daizong Liu, Linchao Bao, Wei Liu, and Pan Zhou. Mhp-vos: Multiple hypotheses propagation for video object segmentation. In CVPR, 2019. 2", + "[99] Linjie Yang, Yuchen Fan, and Ning Xu. Video instance segmentation. In ICCV, 2019. 3", + "[100] Yanchao Yang, Brian Lai, and Stefano Soatto. Dystab: Unsupervised object segmentation via dynamic-static bootstrapping. In CVPR, 2021. 3" + ], + "bbox": [ + 78, + 93, + 470, + 630 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[101] Zhao Yang, Qiang Wang, Luca Bertinetto, Weiming Hu, Song Bai, and Philip HS Torr. Anchor diffusion for unsupervised video object segmentation. In ICCV, 2019. 3", + "[102] Zongxin Yang, Yunchao Wei, and Yi Yang. Collaborative video object segmentation by foreground-background integration. In ECCV, 2020. 2", + "[103] Zongxin Yang, Yunchao Wei, and Yi Yang. Associating objects with transformers for video object segmentation. In M. Ranzato, A. Beygelzimer, Y. Dauphin, P.S. Liang, and J. Wortman Vaughan, editors, NeurIPS, volume 34. Curran Associates, Inc., 2021. 6, 7", + "[104] Zongxin Yang and Yi Yang. Decoupling features in hierarchical propagation for video object segmentation. In NeurIPS, 2022. 2, 6, 7", + "[105] Linwei Ye, Mrigank Rochan, Zhi Liu, Xiaoqin Zhang, and Yang Wang. Referring segmentation in images and videos with cross-modal self-attention network. IEEE TPAMI, 2021. 3", + "[106] Zhaoyuan Yin, Jia Zheng, Weixin Luo, Shenhan Qian, Hanling Zhang, and Shenghua Gao. Learning to recommend frame for interactive video object segmentation in the wild. In CVPR, 2021. 3", + "[107] Jae Shin Yoon, François Rameau, Jun-Sik Kim, Seokju Lee, Seunghak Shin, and In So Kweon. Pixel-level matching for video object segmentation using convolutional neural networks. In ICCV, 2017. 2", + "[108] Xiaohang Zhan, Xingang Pan, Bo Dai, Ziwei Liu, Dahua Lin, and Chen Change Loy. Self-supervised scene de-occlusion. In CVPR, 2020. 3", + "[109] Lu Zhang, Zhe Lin, Jianming Zhang, Huchuan Lu, and You He. Fast video object segmentation via dynamic targeting network. In ICCV, 2019. 2", + "[110] Shifeng Zhang, Longyin Wen, Xiao Bian, Zhen Lei, and Stan Z Li. Occlusion-aware r-cnn: Detecting pedestrians in a crowd. In ECCV, 2018.3", + "[111] Yizhuo Zhang, Zhirong Wu, Houwen Peng, and Stephen Lin. A transductive approach for video object segmentation. In CVPR, 2020. 2", + "[112] Tianfei Zhou, Shunzhou Wang, Yi Zhou, Yazhou Yao, Jianwu Li, and Ling Shao. Motion-attentive transition for zero-shot video object segmentation. In AAAI, 2020. 3", + "[113] Ji Zhu, Hua Yang, Nian Liu, Minyoung Kim, Wenjun Zhang, and Ming-Hsuan Yang. Online multi-object tracking with dual matching attention networks. In ECCV, 2018. 3" + ], + "bbox": [ + 501, + 93, + 890, + 630 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "20234", + "bbox": [ + 478, + 944, + 519, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/aa32c686-8817-467e-b52a-3ad29e222646_model.json b/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/aa32c686-8817-467e-b52a-3ad29e222646_model.json new file mode 100644 index 0000000000000000000000000000000000000000..939ecc77d0e1f79af302f39eb845f0750750a089 --- /dev/null +++ b/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/aa32c686-8817-467e-b52a-3ad29e222646_model.json @@ -0,0 +1,2741 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.112, + 0.131, + 0.859, + 0.154 + ], + "angle": 0, + "content": "MOSE: A New Dataset for Video Object Segmentation in Complex Scenes" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.179, + 0.873, + 0.244 + ], + "angle": 0, + "content": "Henghui Ding\\(^{1}\\) Chang Liu\\(^{1}\\) Shuting He\\(^{1}\\) Xudong Jiang\\(^{1}\\) Philip H.S. Torr\\(^{2}\\) Song Bai\\(^{3}\\) \n\\(^{1}\\)Nanyang Technological University \\(^{2}\\)University of Oxford \\(^{3}\\)ByteDance https://henghuiding.github.io/MOSE" + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.266, + 0.891, + 0.423 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.426, + 0.893, + 0.51 + ], + "angle": 0, + "content": "Figure 1. Examples of video clips from the coMplex video Object SEgmentation (MOSE) dataset. The selected target objects are masked in orange. The most notable feature of MOSE is complex scenarios, including the disappearance-reappearance of objects, small/inconspicuous objects, heavy occlusions, crowded scenarios, etc. For example, the target player in the 2nd row turns around when reappearing in the 4th and 5th columns after disappearing in the 3rd column, bringing challenges in re-identifying him. Most videos in MOSE contain crowded and occluded objects with the target object seldom being the salient one. The goal of MOSE dataset is to provide a platform that promotes the development of more comprehensive and robust video object segmentation algorithms." + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.54, + 0.314, + 0.556 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.573, + 0.473, + 0.875 + ], + "angle": 0, + "content": "Video object segmentation (VOS) aims at segmenting a particular object throughout the entire video clip sequence. The state-of-the-art VOS methods have achieved excellent performance (e.g., \\(90 + \\%\\) J&F) on existing datasets. However, since the target objects in these existing datasets are usually relatively salient, dominant, and isolated, VOS under complex scenes has rarely been studied. To revisit VOS and make it more applicable in the real world, we collect a new VOS dataset called coMplex video Object SEgmentation (MOSE) to study the tracking and segmenting objects in complex scenarios. MOSE contains 2,149 video clips and 5,200 objects from 36 categories, with 431,725 high-quality object segmentation masks. The most notable feature of MOSE dataset is complex scenes with crowded and occluded objects. The target objects in the videos are commonly occluded by others and disappear in some frames. To analyze the proposed MOSE dataset, we benchmark 18 existing VOS methods under 4 different settings on the proposed MOSE dataset and conduct comprehensive comparisons. The experiments show that" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.542, + 0.895, + 0.678 + ], + "angle": 0, + "content": "current VOS algorithms cannot well perceive objects in complex scenes. For example, under the semi-supervised VOS setting, the highest \\( J \\& F \\) by existing state-of-the-art VOS methods is only \\( 59.4\\% \\) on MOSE, much lower than their \\( \\sim 90\\% \\) \\( J \\& F \\) performance on DAVIS. The results reveal that although excellent performance has been achieved on existing benchmarks, there are unresolved challenges under complex scenes and more efforts are desired to explore these challenges in the future." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.709, + 0.633, + 0.724 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Video object segmentation (VOS) [73, 74, 97] aims at segmenting a particular object, e.g., the dominant objects or the objects indicated by users, throughout the entire video sequence. It is one of the most fundamental and challenging computer vision tasks and has a crucial role in many piratical applications that involve video analysis and understanding, e.g., self-driving vehicle, augmented reality, video editing, etc. There are many different settings for VOS, for example, semi-supervised VOS [4, 71] that gives the first-frame mask of the target object, unsupervised VOS [14, 33] that automatically finds primary objects, and" + }, + { + "type": "page_footnote", + "bbox": [ + 0.101, + 0.888, + 0.259, + 0.901 + ], + "angle": 0, + "content": "henghui.ding@gmail.com" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "20224" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.471, + 0.198 + ], + "angle": 0, + "content": "interactive VOS [9, 68] that relies on the user's interactions of the target object. Video object segmentation has been extensively studied in the past using traditional techniques or deep learning methods. Especially, the deep-learning-based methods have greatly improved the performance of video object segmentation and surpassed the traditional techniques by a large margin." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.201, + 0.473, + 0.762 + ], + "angle": 0, + "content": "Current state-of-the-art methods have achieved very high performance on two of the most commonly-used VOS datasets DAVIS [73, 74] and YouTube-VOS [97]. For example, XMem [10] achieves \\(92.0\\%\\) \\(\\mathcal{J}\\& F\\) on DAVIS 2016 [73], \\(87.7\\%\\) \\(\\mathcal{J}\\& F\\) on DAVIS 2017 [74], and \\(86.1\\%\\) \\(\\mathcal{G}\\) on YouTube-VOS [97]. With such a high performance, it seems that the video object segmentation has been well resolved. However, do we really perceive objects in realistic scenarios? To answer this question, we revisit video object segmentation under realistic and more complex scenes. The target objects in existing datasets [73, 74, 97] are usually salient and dominant. In real-world scenarios, isolated and salient objects rarely appear while complex and occluded scenes happen frequently. To evaluate current state-of-the-art VOS methods under more complex scenarios, we collect 2,149 videos with complex scenes and form a new large-scale challenging video object segmentation benchmark, termed coMplex video Object SEgmentation (MOSE). Specifically, there are 5,200 objects from 36 categories in MOSE, with 431,725 high-quality segmentation masks. As shown in Figure 1, the most notable feature of MOSE is complex scenarios, including disappearance-reappearance of objects, small/inconspicuous objects, heavy occlusions, crowded scenarios, etc. For example, the white sedan in the first row of Figure 1 is occluded by the bus, and the heaviest occlusion in 3rd image makes the sedan totally disappear. In the second row of Figure 1, the target player in the crowd is inconspicuous and disappears in the third frame due to the occlusions of the crowd. When the target player reappears, he turns around and shows a different appearance from the first two frames, which makes him very difficult to be tracked. The heavy occlusion and disappearance of objects under complex scenes bring great challenges to video object segmentation. We wish to promote video object segmentation research in complex environments and make VOS applicable in the real world." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.472, + 0.903 + ], + "angle": 0, + "content": "To analyze the proposed MOSE dataset, we retrain and evaluate some existing VOS methods on MOSE. Specifically, we retrain 6 state-of-the-art methods under the semi-supervised setting using mask as the first-frame reference, 2 methods under the semi-supervised setting using bounding box as the first-frame reference, 3 methods under the multi-object zero-shot video object segmentation setting, and 7 methods under interactive setting. The experimental results show that videos of complex scenes make the current" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.198 + ], + "angle": 0, + "content": "state-of-the-art VOS methods less pronounced, especially in terms of tracking objects that disappear for a while due to occlusions. For example, the \\( J \\& F \\) performance of XMem [10] on DAVIS 2016 is \\( 92.0\\% \\) but drop to \\( 57.6\\% \\) on MOSE, the \\( J \\& F \\) performance of DeAOT [104] on DAVIS 2016 is \\( 92.9\\% \\) but drop to \\( 59.4\\% \\) on MOSE, which consistently reveal the difficulties brought by complex scenes." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.199, + 0.892, + 0.319 + ], + "angle": 0, + "content": "The poor performance on MOSE is due to not only occlusions/crowds/small-scale in static images but also objects' disappearance-reappearance and flickering across the temporal domain. While the heavy occlusions, crowds, and small objects bring challenges to the segmentation of objects in images, the disappearance-reappearance of objects makes it extremely difficult to track an occluded object, increasing the challenge of association." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.32, + 0.868, + 0.335 + ], + "angle": 0, + "content": "In a summary, our main contributions are as follows:" + }, + { + "type": "text", + "bbox": [ + 0.517, + 0.349, + 0.892, + 0.409 + ], + "angle": 0, + "content": "- We build a new video object segmentation benchmark dataset termed MOSE (coMplex video Object SEgmentation). MOSE focuses on understanding objects in videos under complex environments." + }, + { + "type": "text", + "bbox": [ + 0.517, + 0.418, + 0.892, + 0.492 + ], + "angle": 0, + "content": "- We conduct comprehensive comparison and evaluation of state-of-the-art VOS methods on the MOSE dataset under 4 different settings, including mask-initialization semi-supervised, box-initialization semi-supervised, unsupervised, and interactive settings." + }, + { + "type": "text", + "bbox": [ + 0.517, + 0.501, + 0.892, + 0.546 + ], + "angle": 0, + "content": "- Taking a close look at MOSE, we analyze the challenges and potential directions for future video understanding research in complex scenes." + }, + { + "type": "list", + "bbox": [ + 0.517, + 0.349, + 0.892, + 0.546 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.563, + 0.642, + 0.579 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.589, + 0.8, + 0.605 + ], + "angle": 0, + "content": "2.1. Video Object Segmentation (VOS)" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.613, + 0.892, + 0.719 + ], + "angle": 0, + "content": "Video object segmentation (VOS) aims at segmenting a particular object throughout the entire video clip sequence. According to how to indicate the particular object, there are mainly four different settings, i.e., semi-supervised VOS (or semi-automatic VOS [89] or one-shot VOS), unsupervised VOS (or automatic VOS [89] or zero-shot VOS), interactive VOS, and referring VOS." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.892, + 0.901 + ], + "angle": 0, + "content": "- Semi-supervised VOS. Semi-supervised video object segmentation (or one-shot video object segmentation) [4] gives the first frame object mask and target to segment the target object throughout the remaining video frames. Most existing works can be categorized into propagation-based methods [8, 13, 25, 30–32, 34, 35, 51, 72, 94, 95, 97, 98, 109] and matching-based methods [13, 21, 22, 29, 40, 69, 85, 91, 102, 107, 111]. The propagation-based methods utilize the mask of previous frame to guide the mask generation of the current frame, propagating the clues of target object frame by frame. The matching-based methods memorize the embedding of target object and then conduct per-pixel" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "20225" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.121 + ], + "angle": 0, + "content": "classification to measure the similarity of each pixel's feature to the embedding of target object." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.123, + 0.468, + 0.213 + ], + "angle": 0, + "content": "Since pixel-wise masks are hard to be obtained, some semi-supervised VOS works propose utilize bounding box as the first-frame clue to indicate the target object [50, 81, 86]. For example, SiamMask [86] applies a mask prediction branch on fully-convolutional Siamese object tracker to generate binary segmentation masks." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.214, + 0.468, + 0.395 + ], + "angle": 0, + "content": "- Interactive VOS. Interactive video object segmentation is a special form of semi-supervised video object segmentation [6, 9, 11, 13, 28, 66, 68, 106], it aims at segmenting the target object in a video indicated by user's interaction, e.g., clicks or scribbles. Existing interactive VOS mainly follows a paradigm of interaction-propagation way. Besides the feature encoder that extracts discriminative pixel features, there are other two modules placed on the feature encoder to achieve interactive video object segmentation, i.e., interactive segmentation module that corrects prediction based on user's interaction and mask propagation module that propagates user-corrected masks to other frames." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.396, + 0.468, + 0.607 + ], + "angle": 0, + "content": "- Referring VOS. Referring video object segmentation [19, 79, 105] is an emerging setting that involves multi-modal information. It gives a natural language expression to indicate the target object and aims at segmenting the target object throughout the video clips. Existing referring video object segmentation methods can be categorized into two ways: bottom-up methods and top-down methods. Bottom-up methods [20, 56, 79] directly segment the target object at the first frame and propagate the mask to the remaining frames, or conduct image segmentation on each frame independently and then associate these masks. Top-down methods [2, 49, 93] exhaustively propose all potential tracklets and select the one that is best matched with language expression as output." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.608, + 0.468, + 0.835 + ], + "angle": 0, + "content": "- Unsupervised VOS. It is also known as automatic VOS or zero-shot VOS [24, 44, 54, 58, 61, 78, 83, 88, 100, 101]. Different from the above VOS settings, unsupervised VOS does not require any manual clues to indicate the objects but aims to automatically find the primary objects in a video. Unsupervised VOS can only deal with objects of pre-defined categories. Early methods usually use post-processing steps [24]. Then end-to-end training methods become the mainstream in unsupervised VOS, which can be categorized into local content encoding and contextual content encoding. The local content encoding methods [14, 33, 43, 44, 82, 83, 112] typically employ two parallel networks to extract features from optical flow and RGB image. The contextual content encoding methods [59, 60, 87] focus on capturing long-term global information." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.847, + 0.379, + 0.862 + ], + "angle": 0, + "content": "2.2. Related Video Segmentation Tasks" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.468, + 0.901 + ], + "angle": 0, + "content": "There are some other video segmentation tasks that are related to video object segmentation, for example, video" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.121 + ], + "angle": 0, + "content": "instance segmentation, video semantic segmentation, and video panoptic segmentation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.123, + 0.892, + 0.349 + ], + "angle": 0, + "content": "- Video Instance Segmentation (VIS). Video instance segmentation is extended from image instance segmentation by Yang et al. [99], it simultaneously conducts detection, segmentation, and tracking of instances of predefined categories in videos. Thanks to the large-scale VIS dataset YouTube-VIS [99], a series of learning methods have been developed and greatly advanced the performance of VIS [36, 48]. Then, occluded video instance segmentation is proposed by [76] to study the video instance segmentation under occluded scenes. Similar to [76], we study video understanding under complex scenarios like occlusions, but different from [76], we focus on video object segmentation (VOS) and our proposed MOSE dataset contains more videos and more complex scenes than [76], especially in terms of object's disappearance-reappearance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.35, + 0.892, + 0.485 + ], + "angle": 0, + "content": "- Video Semantic Segmentation (VSS). Driven by the great success in image semantic segmentation [7, 57] and large-scale video semantic segmentation datasets [3,17,65], video semantic segmentation has drawn lots of attention and achieved significant achievement. Compared to image domain, temporal consistency and model efficiency are the new efforts in the video domain. For example, Sun et al. [80] propose Coarse-to-Fine Feature Mining (CFFM) to capture both static context and motional context." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.487, + 0.892, + 0.637 + ], + "angle": 0, + "content": "- Video Panoptic Segmentation (VPS). Kim et al. [38] introduce panoptic segmentation to the video domain to simultaneously segment and track both the foreground instance objects and background stuff. They build a VPS dataset with 124 videos. Then, Miao et al. [64] build a larger VPS dataset called VIPSeg with 3,536 videos. Existing methods [77, 92] mainly add temporal refinement or cross-frame association modules upon image panoptic segmentation models to enhance temporal conformity and instance tracking performance." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.65, + 0.774, + 0.667 + ], + "angle": 0, + "content": "2.3. Complex Scene Understanding" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.675, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Complex scene understanding has become a research focus in the image understanding domain [15, 18, 39, 41, 47, 63, 90, 108, 110]. For example, Ke et al. [37] propose Bilayer Convolutional Network (BCNet) to decouple overlapping objects into occluder and occludee layers. Zhang et al. [108] propose a self-supervised approach to conduct de-occlusion by ordering recovery, amodal completion, and content completion. On the video domain, however, occlusion understanding is still underexplored with only several multi-object tracking works [16, 55, 96, 113]. For example, Chu et al. [16] propose a spatial temporal attention mechanism (STAM) to capture the visible parts of targets and deal with the drift brought by occlusion. Zhu et al. [113] propose dual matching attention networks (DMAN) to deal with the noisy occlusions in multi-object tracking. Li et al. [46] propose" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.957 + ], + "angle": 0, + "content": "20226" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.089, + 0.472, + 0.132 + ], + "angle": 0, + "content": "Table 1. A complete list of object categories and their #instances in the MOSE dataset. The object categories are sorted in descending order of their frequency of occurrence." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.143, + 0.47, + 0.313 + ], + "angle": 0, + "content": "
CategoryNo.CategoryNo.CategoryNo.CategoryNo.
Person-other519Monkey181Bicycle130Boat73
Fish343Dog175Cyclist116Lizard68
Horse272Boat166Tiger108Duck64
Sheep264Sedan160Giraffe108Goose54
Zebra254Motorcyclist153Panda106Horse-rider46
Rabbit237Turtle142Driver90Bus29
Bird226Cat139Airplane89Truck15
Elephant207Parrot139Chicken86Vehicle-other14
Motorcycle192Cow139Bear84Poultry-other12
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.34, + 0.47, + 0.401 + ], + "angle": 0, + "content": "to track every thing in the open world by performing class-agnostic association. In this work, we build a Complex Video Object Segmentation dataset to support future work on complex scene understanding in VOS." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.416, + 0.229, + 0.433 + ], + "angle": 0, + "content": "3. MOSE Dataset" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.442, + 0.47, + 0.518 + ], + "angle": 0, + "content": "In this section, we introduce the newly built MOSE dataset. We first present the video collection and annotation process in Section 3.1 and then give the dataset statistics and analysis in Section 3.2. Finally, we give the evaluation metrics in Section 3.3." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.53, + 0.367, + 0.545 + ], + "angle": 0, + "content": "3.1. Video Collection and Annotation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.553, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Video Collection. The videos in MOSE are obtained from two sources. The first source is inherited from the OVIS dataset [76], which was designed for video instance segmentation. The second source consists of newly captured videos from real-world scenarios. We chose to include videos from the OVIS dataset because they contain numerous heavy occlusions and meet the requirements of complex scenes. However, for videos inherited from OVIS, since many objects appear for the first time after the first frame, they cannot be directly used for video object segmentation, which requires a first-frame reference. One solution would be to discard all objects that do not appear in the first frame, but this would result in a significant waste of mask annotations. To make full use of OVIS videos and adapt them for video object segmentation tasks, we cut each of these videos into several videos according to the frame where each object first appears in the videos. We then discard videos that do not meet our requirements. For the newly captured videos, we first select a set of semantic categories that are common in the real world, including vehicles (e.g., bicycle, bus, airplane, boat), animals (e.g., bird, panda, dog, giraffe), and human beings in different activities (e.g., motorcycling, driving, riding, running), and" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.212 + ], + "angle": 0, + "content": "then collect/film videos containing these categories from the campus, zoo, indoor, city street, etc. A complete list of object categories in the MOSE dataset can be seen in Table 1. These categories are common in our daily lives, where crowds and occlusions frequently occur. Moreover, they are included in popular large-scale image segmentation datasets such as MS-COCO [52], which makes it easy to use image-pretrained models." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.213, + 0.892, + 0.289 + ], + "angle": 0, + "content": "Our primary concern is video object segmentation under complex scenes that contain crowds, occlusion, multi-scale objects, and other challenging scenarios. Therefore, we established several rules to ensure that complex environments are included when collecting/shooting videos:" + }, + { + "type": "text", + "bbox": [ + 0.502, + 0.298, + 0.892, + 0.359 + ], + "angle": 0, + "content": "R1. Each video must contain several objects, while videos with only a single object are excluded. Specifically, videos with crowded objects of similar appearance are highly valued." + }, + { + "type": "text", + "bbox": [ + 0.502, + 0.366, + 0.892, + 0.428 + ], + "angle": 0, + "content": "R2. Occlusions should be present in the video. Videos that do not have any occlusions throughout the entirety of the frames are discarded. We encourage occlusions caused by other moving objects." + }, + { + "type": "text", + "bbox": [ + 0.502, + 0.434, + 0.892, + 0.48 + ], + "angle": 0, + "content": "R3. Great emphasis should be placed on scenarios where objects disappear and then reappear due to occlusions or crowding." + }, + { + "type": "text", + "bbox": [ + 0.502, + 0.487, + 0.892, + 0.533 + ], + "angle": 0, + "content": "R4. The target objects should be of a variety of scales and types, such as small-scale or large-scale, conspicuous or inconspicuous." + }, + { + "type": "text", + "bbox": [ + 0.502, + 0.54, + 0.892, + 0.585 + ], + "angle": 0, + "content": "R5. Objects in the video must show sufficient motion. Videos with completely still objects or very little motion are discarded." + }, + { + "type": "list", + "bbox": [ + 0.502, + 0.298, + 0.892, + 0.585 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.596, + 0.892, + 0.657 + ], + "angle": 0, + "content": "Besides the rules mentioned above, we also require the video quality to be of high standard, which means the video resolution should be \\(1920 \\times 1080\\) and the video length should be between 5 to 60 seconds in general." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.674, + 0.892, + 0.81 + ], + "angle": 0, + "content": "Video Annotation. Having all videos for MOSE been collected, our research team looks through them and figure out a set of targets-of-interest for each of the videos. Then we slightly clip the start and the end of videos, to reduce the number of less motional or simple frames in the video. Next we annotate the first-frame mask of the target objects, as VOS input. Following this, the videos are sent to the annotation team along with the first-frame masks for annotation of the subsequent video frames." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Using the given first-frame mask as a reference, the annotation team is required to identify the target object in the given first-frame mask, then track and annotate the segmentation mask of the target object in all frames following the first frame. The process of annotating videos has been made easier with the help of an interactive annotation tool" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "20227" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.089, + 0.895, + 0.161 + ], + "angle": 0, + "content": "Table 2. Scale comparison between MOSE and existing VOS datasets. \"Annotations\" denotes the number of annotated object masks. \"Duration\" denotes the total duration (in minutes) of the annotated videos. \"mBOR\" denotes the mean of the Bounding-box-Occlusion Rate. \"Disapp. Rate\" represents the frequency of objects that disappear in at least one frame. The newly built MOSE has the longest video duration and the largest number of annotations. More importantly, the most notable feature of MOSE is that it contains lots of crowds, occlusions, and disappearance-reappearance objects, which provide much more complex scenarios for video object segmentation." + }, + { + "type": "table", + "bbox": [ + 0.089, + 0.165, + 0.885, + 0.321 + ], + "angle": 0, + "content": "
DatasetYearVideosCategoriesObjectsAnnotationsDurationmBORDisapp. Rate
YouTube-Objects [75]20129610961,6929.01--
SegTrack-v2 [42]20131411241,4750.590.128.3%
FBMS [67]201459161391,4657.700.0111.2%
JumpCut [23]20152214226,3313.5200%
DAVIS16 [73]201650-503,4402.88--
DAVIS17 [74]201790-20513,5435.170.0316.1%
YouTube-VOS [97]20184,453947,755197,272334.810.0513.0%
MOSE (ours)20232,149365,200431,725443.620.2341.5%
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.357, + 0.473, + 0.599 + ], + "angle": 0, + "content": "that we developed. The annotation tool automatically loads videos and all target objects. Annotators use the tool to load and preview videos and first-frame masks, annotate and visualize the segmentation masks in the subsequent frames, and save them. The annotation tool also has a built-in interactive object segmentation network XMem [10], to assist annotations in producing high-quality masks. To ensure the annotation quality under complex scenes, the annotators are required to clearly track the object that disappears and reappears due to heavy occlusions and crowd. For frames in which the target object is disappeared or is fully occluded, annotators also need to confirm that the output masks of such frames shall be blank. It is a requirement that all of our videos be annotated every five frames at the very least. For the purpose of testing the frame-rate robustness of the models, some videos are annotated every frame." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.599, + 0.472, + 0.66 + ], + "angle": 0, + "content": "After annotation, the videos are reviewed by our verification team to ensure high-quality annotations, particularly for videos containing occlusions, crowds, or instances of objects disappearing and reappearing." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.667, + 0.248, + 0.683 + ], + "angle": 0, + "content": "3.2. Dataset Statistics" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.689, + 0.473, + 0.901 + ], + "angle": 0, + "content": "In Table 2, we analyze the data statistics of the new MOSE dataset using previous datasets for the video object segmentation as a reference for the analysis, including JumpCut [23], SegTrack-v2 [42], YouTube-Objects [75], FBMS [67], DAVIS [73, 74], and YouTube-VOS [97]. As shown in Table 2, there are 2,149 videos and 431,725 mask annotations for 5,200 objects contained in the proposed MOSE dataset. Comparing with previous largest VOS dataset YouTube-VOS [97], MOSE has much more mask annotations, \\(431\\mathrm{k}\\) vs. \\(197\\mathrm{k}\\). Among the 8 video object segmentation datasets that we analyzed in Table 2, MOSE has the longest video duration (433.62 minutes), which is about 100 minutes longer than the second longest dataset YouTube-VOS (334.81 minutes) and is hundreds of times" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.355, + 0.646, + 0.417 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.647, + 0.355, + 0.789, + 0.418 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.79, + 0.355, + 0.887, + 0.418 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.626, + 0.419, + 0.767, + 0.43 + ], + "angle": 0, + "content": "Low occlusion but high BOR" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.432, + 0.646, + 0.495 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.647, + 0.432, + 0.79, + 0.495 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.791, + 0.432, + 0.887, + 0.495 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.626, + 0.496, + 0.766, + 0.506 + ], + "angle": 0, + "content": "High occlusion but low BOR" + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.52, + 0.895, + 0.577 + ], + "angle": 0, + "content": "Figure 2. Failure cases of the BOR indicator. It can be seen from the first row of samples that they have high BOR values, but there is less or no occlusion present. Samples in the second row have very small BOR values, but there are severe occlusions in the samples." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.605, + 0.895, + 0.682 + ], + "angle": 0, + "content": "longer than the other seven datasets. We include more long videos in the MOSE compared to previous VOS datasets to ensure that our dataset contains a diverse range of occlusion scenarios, motion scenarios, and instances of objects disappearing and reappearing." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Disappearance and Occlusion Analysis. Previous occluded video datasets OVIS [76] defines a Bounding-box Occlusion Rate (BOR) to reflect the occlusion degree. The BOR is calculated by the Intersection-over-Union of bounding boxes in the videos. We provide the mean of BOR of all frames in Table 2. The MOSE has the largest value of mBOR, indicating the more frequency of occlusions in MOSE than previous datasets. However, we find that BOR can only roughly reflect the occlusion. It does not well reveal the degree of occlusion in the MOSE dataset and may be prone to making some mistakes in this regard. As shown in the first row of Figure 2, high BOR is observed in the three images with low occlusion or even no occlusion. In" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "20228" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.121 + ], + "angle": 0, + "content": "contrast, in the images of the second row, where there are heavily occluded objects, the BOR is low and even 0." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.122, + 0.471, + 0.318 + ], + "angle": 0, + "content": "Therefore, besides counting BOR, we further calculate the number of disappeared objects that disappear in at least one frame of the video, followed by the disappearance rate that reflects the frequency of disappearances, which illustrates how often the disappearance of objects occurs due to complex scenarios in a dataset. As shown in Table 2, the disappearance rate (Disapp. Rate) of MOSE stands at the highest, reaching \\(41.5\\%\\). Meanwhile, a total of \\(27.0\\%\\) of objects in MOSE showcase the disappearance-reappearance phenomenon, meaning they completely vanish and subsequently reappear in future frames. These observations underscore the frequent and substantial occurrence of disappearance and occlusions in the proposed MOSE dataset." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.337, + 0.262, + 0.352 + ], + "angle": 0, + "content": "3.3. Evaluation Metrics" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.361, + 0.47, + 0.452 + ], + "angle": 0, + "content": "In accordance with the previous method [73, 74], we compute the region similarity \\( \\mathcal{J} \\) and the contour accuracy \\( \\mathcal{F} \\) as evaluation metrics. Given segmentation mask predictions \\( \\hat{M} \\in \\{0,1\\}^{H\\times W} \\) and the ground-truth masks \\( M \\in \\{0,1\\}^{H\\times W} \\), region similarity \\( \\mathcal{J} \\) is obtained by calculating the Intersection-over-Union (IoU) of \\( \\hat{M} \\) and \\( M \\)," + }, + { + "type": "equation", + "bbox": [ + 0.227, + 0.46, + 0.47, + 0.49 + ], + "angle": 0, + "content": "\\[\n\\mathcal {J} = \\frac {\\hat {M} \\cap M}{\\hat {M} \\cup M}. \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.493, + 0.47, + 0.6 + ], + "angle": 0, + "content": "Then, the average region similarity \\( J_{mean} \\) over all objects is calculated as the final region similarity result. We use \\( J \\) to represent \\( J_{mean} \\) for the sake of brevity. To measure the contour quality of \\( \\hat{M} \\), contour recall \\( \\mathbf{R}_c \\) and precision \\( \\mathrm{P}_c \\) are calculated via bipartite graph matching [62]. Then, the contour accuracy \\( F \\) is the harmonic mean of the contour recall \\( \\mathbf{R}_c \\) and precision \\( \\mathrm{P}_c \\), i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.229, + 0.606, + 0.47, + 0.639 + ], + "angle": 0, + "content": "\\[\n\\mathcal {F} = \\frac {2 \\mathrm {P} _ {c} \\mathrm {R} _ {c}}{\\mathrm {P} _ {c} + \\mathrm {R} _ {c}}, \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.644, + 0.47, + 0.735 + ], + "angle": 0, + "content": "which represents how closely the contours of predicted masks resemble the contours of ground-truth masks. The average contour accuracy \\( \\mathcal{F}_{mean} \\) over all objects is calculated as the final contour accuracy result. We use \\( \\mathcal{F} \\) to represent \\( \\mathcal{F}_{mean} \\) for the sake of brevity. Then, \\( J\\& F = (J + F) / 2 \\) is used to measure the overall performance." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.748, + 0.21, + 0.765 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.773, + 0.469, + 0.864 + ], + "angle": 0, + "content": "Herein we conduct experiments and benchmarks on four different Video Object Segmentation (VOS) settings, including semi-supervised (or one-shot) VOS with mask-initialization, semi-supervised VOS with box-initialization, unsupervised (or zero-shot) VOS, and interactive VOS, to comprehensively analyze the newly built MOSE dataset." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.871, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Implementation Details. The proposed MOSE dataset is consistent with the YouTube-VOS [97] format. We replace" + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.09, + 0.892, + 0.16 + ], + "angle": 0, + "content": "Table 3. Comparisons of state-of-the-art semi-supervised methods on the validation set. “\\(\\mathcal{J}\\)” and “\\(\\mathcal{F}\\)” denote the mean of region similarity and the mean of contour accuracy. \\(\\mathcal{J} \\& \\mathcal{F}\\) denotes the mean of \\(\\mathcal{J}\\) and \\(\\mathcal{F}\\). BL30K [11] is not added during the training stage to make a fair comparison." + }, + { + "type": "table", + "bbox": [ + 0.508, + 0.164, + 0.887, + 0.299 + ], + "angle": 0, + "content": "
MethodPub.MOSE (ours)DAVIS17YT-VOS18
JFJ&FJ&FG
AOT [103]NeurIPS'2153.161.357.284.984.1
STCN [12]NeurIPS'2146.655.050.885.483.0
RDE [45]CVPR'2244.652.948.884.2-
SWEM [53]CVPR'2246.854.950.984.382.8
XMem [10]ECCV'2253.362.057.686.285.7
DeAOT [104]NeurIPS'2255.163.859.485.286.0
" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.324, + 0.892, + 0.446 + ], + "angle": 0, + "content": "the training dataset of previous methods from YouTube-VOS with our MOSE and strictly follow their training settings on YouTube-VOS [97]. We follow DAVIS [73, 74] to evaluate the performance and report the results of \\( \\mathcal{J}_{\\text{mean}} \\), \\( \\mathcal{F}_{\\text{mean}} \\), and \\( \\mathcal{J} \\& \\mathcal{F} \\) on the validation set of MOSE. During the training of these VOS methods, we follow their way of using image pre-trained models but do not use any additional video datasets for pretraining." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.455, + 0.892, + 0.576 + ], + "angle": 0, + "content": "Settings. There are 2,149 videos in the whole MOSE dataset. These videos are split into 1,507 training videos, 311 validation videos, and 331 testing videos, for model training, daily evaluation, and competition period evaluation, respectively. Each of the videos gives a first-frame mask or bounding box as the reference of the target object for the semi-supervised (one-shot) VOS setting, and first-frame scribbles for the interactive VOS setting." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.587, + 0.878, + 0.604 + ], + "angle": 0, + "content": "4.1. Semi-supervised Video Object Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.61, + 0.892, + 0.761 + ], + "angle": 0, + "content": "Semi-supervised video object segmentation, or one-shot video object segmentation, gives either the first frame mask or bounding box of the target object as a clue and reference. We train and evaluate the very recent 6 mask-initialization semi-supervised VOS methods and 2 box-initialization semi-supervised VOS methods built upon ResNet-50 [26] on the MOSE dataset, as shown in Table 3 and Table 4, respectively. It is our hope that the experiments will provide baselines for future semi-supervised VOS algorithms to be developed." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Mask-initialization. This setting is a classic and currently the most popular topic for video object segmentation. A lot of excellent deep-learning-based works have been developed for this setting in the past decade and greatly improve the video object segmentation performance to a saturation level. For example, the most recent state-of-the-art method DeAOT [104] achieves \\(85.2\\%\\) \\(\\mathcal{J}\\& \\mathcal{F}\\) on the DAVIS 2017 [74], \\(86.0\\%\\) \\(\\mathcal{G}\\) on YouTube-VOS [97], and \\(92.3\\%\\) \\(\\mathcal{J}\\& \\mathcal{F}\\) on DAVIS 2016 [73], which are excellent" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "20229" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.089, + 0.472, + 0.146 + ], + "angle": 0, + "content": "Table 4. Comparisons of state-of-the-art box-initialization semi-supervised methods on the validation set. \"J\" and \"F\" denote the mean of region similarity and the mean of contour accuracy. J&F denotes the mean of \\( \\mathcal{I} \\) and \\( \\mathcal{F} \\)." + }, + { + "type": "table", + "bbox": [ + 0.08, + 0.15, + 0.469, + 0.212 + ], + "angle": 0, + "content": "
MethodPub.MOSE (ours)DAVIS17YT-VOS18
JFJ&FJ&FG
SiamMask [86]CVPR'1917.326.722.056.452.8
FTMU [81]CVPR'2019.128.523.870.6-
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.227, + 0.473, + 0.514 + ], + "angle": 0, + "content": "performance and almost reach the ground truth. To analyze the newly built MOSE dataset and test the performance of existing methods in complex scenes, we train and evaluate these methods on MOSE. We report the results of 6 recent state-of-the-art methods on the validation set of MOSE, including AOT [103], STCN [12], RDE [45], SWEM [53], XMem [10], and DeAOT [104], as shown in Table 3. Current state-of-the-art methods only achieve the performance from \\(48.8\\%\\) \\(\\mathcal{J}\\& \\mathcal{F}\\) to \\(59.4\\%\\) \\(\\mathcal{J}\\& \\mathcal{F}\\) on the validation set of the newly proposed MOSE dataset, while their results on DAVIS 2017 [74] and YouTube-VOS [97] are usually above \\(80\\%\\) \\(\\mathcal{J}\\& \\mathcal{F}\\) or \\(\\mathcal{G}\\), some of them almost reach \\(90\\%\\) \\(\\mathcal{J}\\& \\mathcal{F}\\) or \\(\\mathcal{G}\\) on DAVIS 2017 and YouTube-VOS. The results reveal that although we have achieved excellent VOS performance on previous benchmarks, there are unresolved challenges under complex scenes and more efforts are desired to explore these challenges in the future. Discussion about the MOSE dataset and some potential future directions are provided in Section 5." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.519, + 0.47, + 0.639 + ], + "angle": 0, + "content": "Box-initialization. As shown in Table 4, two semi-supervised (one-shot) VOS methods with a bounding box as the first-frame reference are trained on MOSE and evaluated on the validation set of MOSE, including SimMask [86] and FTMU [81]. Current state-of-the-art methods achieve only \\(22.0\\%\\) and \\(23.8\\%\\) \\(\\mathcal{J}\\& \\mathcal{F}\\) on the validation set of the newly proposed MOSE dataset, while their results on DAVIS 2017 [74] are already \\(70 + \\%\\) \\(\\mathcal{J}\\& \\mathcal{F}\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.64, + 0.471, + 0.822 + ], + "angle": 0, + "content": "After careful analysis, we believe that one of the reasons for such a significant drop in performance is that there are many heavy occlusions, small-scale objects, and crowded scenarios in the videos of MOSE dataset, which make the weakly supervised segmentation of the videos much more difficult. There is a possibility that, even within the target bounding box region, the target object may not the most salient one due to heavy occlusions and crowd. The occlusion of an object can cause it to be broken up into several pieces that are not adjacent to each other, which greatly increases the difficulty of segmenting an object using a box-driven approach." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.832, + 0.433, + 0.849 + ], + "angle": 0, + "content": "4.2. Unsupervised Video Object Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Unsupervised video object segmentation, or zero-shot video object segmentation, does not require any manual clues (e.g., mask or bounding box) as a reference to indicate" + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.089, + 0.892, + 0.145 + ], + "angle": 0, + "content": "Table 5. Comparisons of state-of-the-art multi-object zero-shot VOS methods on the validation set. \"J\" and \"F\" denote the mean of region similarity and the mean of contour accuracy. J&F denotes the mean of \\( \\mathcal{I} \\) and \\( \\mathcal{F} \\)." + }, + { + "type": "table", + "bbox": [ + 0.509, + 0.15, + 0.886, + 0.227 + ], + "angle": 0, + "content": "
MethodPub.MOSE (ours)DAVIS17
JFJ&FJ&F
RVOS [84]CVPR'1924.136.930.543.7
AGNN [87]ICCV'1938.648.843.761.1
STEm-Seg [1]ECCV'2043.350.546.964.7
" + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.241, + 0.892, + 0.283 + ], + "angle": 0, + "content": "Table 6. Comparisons of state-of-the-art interactive VOS methods on the validation set. \\( J \\& F @60s \\) denotes the \\( J \\& F \\) performance reached by methods within 60 seconds interactions." + }, + { + "type": "table", + "bbox": [ + 0.503, + 0.287, + 0.89, + 0.421 + ], + "angle": 0, + "content": "
MethodPub.MOSE (ours) J&F@60sDAVIS17 J&F@60s
IPNet [68]CVPR'1941.278.7
STM [70]ICCV'1945.384.8
MANet [66]CVPR'2043.679.5
ATNet [27]ECCV'2044.582.7
GIS [28]CVPR'2150.286.6
MiVOS [11]CVPR'2151.488.5
STCN [12]NeurIPS'2156.888.8
" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.44, + 0.892, + 0.639 + ], + "angle": 0, + "content": "the objects but aims to find the primary objects in a video automatically. The mainstream of zero-shot VOS methods focuses on addressing single-object VOS. However, MOSE is a multi-object VOS dataset like DAVIS 2017 [74], thus we only benchmark multi-object zero-shot VOS methods on MOSE, e.g., STEm-Seg [1], AGNN [87], and RVOS [84]. The results are shown in Table 5. In this setting, only videos with exhaustive first-frame annotations are used. Existing methods rely on off-the-shelf image-trained instance segmentation methods, which can well detect/segment objects in the static image thanks to complex scene learning in the image domain. The performance drop is mainly due to temporal challenges." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.65, + 0.836, + 0.667 + ], + "angle": 0, + "content": "4.3. Interactive Video Object Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.674, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Following the interactive track of DAVIS 2019 Challenge [5], we provide initial scribbles for the target object in a specific video sequence, which are used as the first interaction. The interactive video object segmentation methods are required to predict the segmentation mask for the whole video based on the first interaction. Then, by comparing predicted masks and ground truth masks across the video, corrective scribbles on the worst frame are further provided for the methods to refine the video segmentation prediction. The above step is allowed to be repeated up to 8 times with a time limitation of 30s for each object. We report the metric of \\( J \\& F \\)@60s to encourage the methods to have a good balance between speed and accuracy. As shown in Table 6, seven recent interactive video object segmentation methods are evaluated on the validation set of MOSE." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "20230" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.09, + 0.38, + 0.107 + ], + "angle": 0, + "content": "5. Discussion and Future Directions" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.116, + 0.47, + 0.176 + ], + "angle": 0, + "content": "Herein we discuss the challenges of the proposed MOSE dataset brought by complex scenes and provide some potential future directions based on the experimental results analysis of the existing methods on MOSE." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.18, + 0.47, + 0.346 + ], + "angle": 0, + "content": "- Stronger Association to Track Reappearing Objects. It is necessary to develop stronger association/re-identification algorithms for VOS methods in order to be able to track objects that disappear and then reappear. Especially, the most interesting thing is that we have noticed that a number of disappeared-then-reappeared objects have been reappearing with a different appearance from the time they disappeared, i.e., appearance-changing objects. For example, the target player in Figure 1 shows his back before disappearing while showing the front at reappearing. There is a great deal of difficulty in tracking with such an appearance change." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.349, + 0.47, + 0.591 + ], + "angle": 0, + "content": "- Video Object Segmentation of Occluded Objects. The frequent occlusions in the videos of MOSE provide data support to the research of occlusion video understanding. Tracking and segmenting an object with heavy occlusion have rarely been studied since the target objects in existing datasets are usually salient and dominant. In real-world scenarios, isolated objects rarely appear while occluded scenes occur frequently. Our human beings can well capture those occluded objects, thanks to our contextual association and reasoning ability. With the introduction of an understanding of occlusion into the process of video object segmentation, the VOS methods will become more practical for use in real-world applications. Especially, the occlusions make the box-initialization semi-supervised VOS setting more challenging in terms of segmenting an occluded object by bounding box." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.596, + 0.47, + 0.821 + ], + "angle": 0, + "content": "- Attention on Small & Inconspicuous Objects. Although the detection and segmentation of small objects is a hot topic in the image domain, tracking and segmenting small and inconspicuous objects in the video object segmentation domain is still to be developed. As a matter of fact, most of the existing video object segmentation methods mainly focus on tracking large and salient objects. The lack of sufficient attention to small-scale objects makes the video object segmentation methods less pronounced in practical applications that may involve target objects of varying sizes and types. There are many objects in the proposed MOSE dataset that are on a small scale and are inconspicuous in the videos, which provides a greater opportunity for the research of tracking and segmenting objects that are small and inconspicuous in realistic scenarios." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.47, + 0.902 + ], + "angle": 0, + "content": "- Tracking Objects in Crowd. One of the most notable features of the MOSE is crowded scenarios, which are common in real-world applications. There are many videos in the MOSE dataset, which contain crowd objects, such as flocks of sheep moving together, groups of cyclists racing," + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.258 + ], + "angle": 0, + "content": "pedestrians moving on a crowded street, and etc. A scenario like this presents challenges when it comes to segmenting and tracking one object among a crowd of objects that share a similar appearance and motion to the target object with the crowd as a whole. In the image/frame domain, it is desired for video object segmentation algorithms to enhance the identification ability to distinguish between different objects with a similar appearance. What's more, in the temporal domain, it is challenging to perform the object association between the two frames with the crowd consisting of similar-looking objects." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.263, + 0.892, + 0.535 + ], + "angle": 0, + "content": "- Long-Term Video Segmentation: In terms of practical applications like movie editing and surveillance monitoring, long-term video understanding is much more practical than short-term video understanding. For example, the average length of videos on YouTube is around twelve minutes, which is much longer than the average length of the existing video object segmentation dataset. Although existing VOS methods provide excellent performance, they typically require a lot of computing resources, e.g., GPU memory, for storing the object features of previous frames. Due to the large computation cost, most existing VOS methods cannot well handle long videos. The average video length of the MOSE dataset is longer than existing VOS datasets, bringing more challenges and opportunities in dealing with long-term videos. It is a good and practical direction to design VOS algorithms that can deal with long videos with low computation costs while achieving high-quality segmentation results." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.557, + 0.618, + 0.572 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.584, + 0.892, + 0.901 + ], + "angle": 0, + "content": "We build a large-scale video object segmentation dataset named MOSE to revisit and support the research of video object segmentation under complex scenes. There are 2,149 high-resolution videos in MOSE with 431,725 high-quality object masks for 5,200 objects from 36 categories. The videos in MOSE are commonly long enough to ensure diverse and sufficient occlusion, motion, and disappearance-reappearance scenarios. Based on the proposed MOSE dataset, we benchmark existing VOS methods and conduct a comprehensive comparison. We train and evaluate six methods under the semi-supervised (one-shot) setting with a mask as the first-frame reference, two methods with a bounding box as the first-frame reference, three methods under the unsupervised (zero-shot) setting, and seven methods under the interactive setting. After evaluating existing VOS methods on MOSE dataset and comprehensively analyzing the results, some challenges and potential directions for future VOS research are concluded. We find that we are still at a nascent stage of segmenting and tracking objects in complex scenes where crowds, disappearing, occlusions, and inconspicuous/small objects occur frequently." + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.946, + 0.518, + 0.957 + ], + "angle": 0, + "content": "20231" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.091, + 0.174, + 0.105 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.093, + 0.115, + 0.47, + 0.151 + ], + "angle": 0, + "content": "[1] Ali Athar, Sabarinath Mahadevan, Aljosa Osep, Laura Leal-Taixe, and Bastian Leibe. Stem-seg: Spatio-temporal embeddings for instance segmentation in videos. In ECCV, 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.093, + 0.152, + 0.47, + 0.187 + ], + "angle": 0, + "content": "[2] Adam Botach, Evgenii Zheltonozhskii, and Chaim Baskin. End-to-end referring video object segmentation with multimodal transformers. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.093, + 0.188, + 0.469, + 0.224 + ], + "angle": 0, + "content": "[3] Gabriel J Brostow, Julien Fauqueur, and Roberto Cipolla. Semantic object classes in video: A high-definition ground truth database. Pattern Recognition Letters, 30(2), 2009. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.093, + 0.225, + 0.469, + 0.262 + ], + "angle": 0, + "content": "[4] Sergi Caelles, Kevis-Kokitsi Maninis, Jordi Pont-Tuset, Laura Leal-Taixe, Daniel Cremers, and Luc Van Gool. One-shot video object segmentation. In CVPR, 2017. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.093, + 0.263, + 0.469, + 0.31 + ], + "angle": 0, + "content": "[5] Sergi Caelles, Jordi Pont-Tuset, Federico Perazzi, Alberto Montes, Kevis-Kokitsi Maninis, and Luc Van Gool. The 2019 davis challenge on vos: Unsupervised multi-object segmentation. arXiv:1905.00737, 2019. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.093, + 0.311, + 0.469, + 0.348 + ], + "angle": 0, + "content": "[6] Bowen Chen, Huan Ling, Xiaohui Zeng, Gao Jun, Ziyue Xu, and Sanja Fidler. Scribblebox: Interactive annotation framework for video object segmentation. In ECCV, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.093, + 0.349, + 0.469, + 0.396 + ], + "angle": 0, + "content": "[7] Liang-Chieh Chen, George Papandreou, Iasonas Kokkinos, Kevin Murphy, and Alan L Yuille. Deep convolution with deep convolutional nets, atrous convolution, and fully connected crfs. IEEE TPAMI, 40(4), 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.093, + 0.398, + 0.469, + 0.433 + ], + "angle": 0, + "content": "[8] Xi Chen, Zuoxin Li, Ye Yuan, Gang Yu, Jianxin Shen, and Donglian Qi. State-aware tracker for real-time video object segmentation. In CVPR, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.093, + 0.435, + 0.469, + 0.47 + ], + "angle": 0, + "content": "[9] Yuhua Chen, Jordi Pont-Tuset, Alberto Montes, and Luc Van Gool. Blazingly fast video object segmentation with pixel-wise metric learning. In CVPR, 2018. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.471, + 0.469, + 0.508 + ], + "angle": 0, + "content": "[10] Ho Kei Cheng and Alexander G Schwing. Xmem: Long-term video object segmentation with an atkinson-shiffrin memory model. In ECCV. Springer, 2022. 2, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.508, + 0.469, + 0.544 + ], + "angle": 0, + "content": "[11] Ho Kei Cheng, Yu-Wing Tai, and Chi-Keung Tang. Modular interactive video object segmentation: Interaction-to-mask, propagation and difference-aware fusion. In CVPR, 2021. 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.545, + 0.469, + 0.581 + ], + "angle": 0, + "content": "[12] Ho Kei Cheng, Yu-Wing Tai, and Chi-Keung Tang. Rethinking space-time networks with improved memory coverage for efficient video object segmentation. In NeurIPS, 2021. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.582, + 0.469, + 0.618 + ], + "angle": 0, + "content": "[13] Jingchun Cheng, Yi-Hsuan Tsai, Wei-Chih Hung, Shengjin Wang, and Ming-Hsuan Yang. Fast and accurate online video object segmentation via tracking parts. In CVPR, 2018. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.619, + 0.469, + 0.655 + ], + "angle": 0, + "content": "[14] Jingchun Cheng, Yi-Hsuan Tsai, Shengjin Wang, and Ming-Hsuan Yang. Segflow: Joint learning for video object segmentation and optical flow. In ICCV, 2017. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.656, + 0.469, + 0.692 + ], + "angle": 0, + "content": "[15] Meng-Jiun Chiou, Henghui Ding, Hanshu Yan, Changhu Wang, Roger Zimmermann, and Jiashi Feng. Recovering the unbiased scene graphs from the biased ones. In ACM MM, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.693, + 0.469, + 0.74 + ], + "angle": 0, + "content": "[16] Qi Chu, Wanli Ouyang, Hongsheng Li, Xiaogang Wang, Bin Liu, and Nenghai Yu. Online multi-object tracking using cnn-based single object tracker with spatial-temporal attention mechanism. In ICCV, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.741, + 0.469, + 0.789 + ], + "angle": 0, + "content": "[17] Marius Cordts, Mohamed Omran, Sebastian Ramos, Timo Rehfeld, Markus Enzweiler, Rodrigo Benenson, Uwe Franke, Stefan Roth, and Bernt Schiele. The cityscapes dataset for semantic urban scene understanding. In CVPR, 2016. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.79, + 0.469, + 0.827 + ], + "angle": 0, + "content": "[18] Henghui Ding, Xudong Jiang, Bing Shuai, Ai Qun Liu, and Gang Wang. Semantic segmentation with context encoding and multi-path decoding. IEEE TIP, 29, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.828, + 0.469, + 0.864 + ], + "angle": 0, + "content": "[19] Henghui Ding, Chang Liu, Shuting He, Xudong Jiang, and Chen Change Loy. MeViS: A large-scale benchmark for video segmentation with motion expressions. In ICCV, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.865, + 0.469, + 0.9 + ], + "angle": 0, + "content": "[20] Henghui Ding, Chang Liu, Suchen Wang, and Xudong Jiang. VLT: Vision-language transformer and query generation for referring segmentation. IEEE TPAMI, 2023. 3" + }, + { + "type": "list", + "bbox": [ + 0.087, + 0.115, + 0.47, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.094, + 0.891, + 0.129 + ], + "angle": 0, + "content": "[21] Kevin Duarte, Yogesh S. Rawat, and Mubarak Shah. Capsulevos: Semi-supervised video object segmentation using capsule routing. In ICCV, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.13, + 0.891, + 0.166 + ], + "angle": 0, + "content": "[22] Brendan Duke, Abdalla Ahmed, Christian Wolf, Parham Aarabi, and Graham W Taylor. Sstvos: Sparse spatiotemporal transformers for video object segmentation. In CVPR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.168, + 0.891, + 0.214 + ], + "angle": 0, + "content": "[23] Qingnan Fan, Fan Zhong, Dani Lischinski, Daniel Cohen-Or, and Baoquan Chen. JumpCut: non-successive mask transfer and interpolation for video cutout. ACM Tran. Graphics, 34(6), 2015. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.216, + 0.891, + 0.251 + ], + "angle": 0, + "content": "[24] Katerina Fragkiadaki, Pablo Arbelaez, Panna Felsen, and Jitendra Malik. Learning to segment moving objects in videos. In CVPR, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.252, + 0.891, + 0.289 + ], + "angle": 0, + "content": "[25] Junwei Han, Le Yang, Dingwen Zhang, Xiaojun Chang, and Xiaodan Liang. Reinforcement cutting-agent learning for video object segmentation. In CVPR, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.29, + 0.891, + 0.314 + ], + "angle": 0, + "content": "[26] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, 2016. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.315, + 0.891, + 0.35 + ], + "angle": 0, + "content": "[27] Yuk Heo, Yeong Jun Koh, and Chang-Su Kim. Interactive video object segmentation using global and local transfer modules. In ECCV, 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.351, + 0.891, + 0.386 + ], + "angle": 0, + "content": "[28] Yuk Heo, Yeong Jun Koh, and Chang-Su Kim. Guided interactive video object segmentation using reliability-based attention maps. In CVPR, 2021. 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.388, + 0.891, + 0.423 + ], + "angle": 0, + "content": "[29] Li Hu, Peng Zhang, Bang Zhang, Pan Pan, Yinghui Xu, and Rong Jin. Learning position and target consistency for memory-based video object segmentation. In CVPR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.424, + 0.891, + 0.46 + ], + "angle": 0, + "content": "[30] Ping Hu, Gang Wang, Xiangfei Kong, Jason Kuen, and Yap-Peng Tan. Motion-guided cascaded refinement network for video object segmentation. In CVPR, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.461, + 0.891, + 0.496 + ], + "angle": 0, + "content": "[31] Xuhua Huang, Jiarui Xu, Yu-Wing Tai, and Chi-Keung Tang. Fast video object segmentation with temporal aggregation network and dynamic template matching. In CVPR, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.497, + 0.891, + 0.533 + ], + "angle": 0, + "content": "[32] Allan Jabri, Andrew Owens, and Alexei Efros. Space-time correspondence as a contrastive random walk. In NeurIPS, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.534, + 0.891, + 0.57 + ], + "angle": 0, + "content": "[33] Suyog Dutt Jain, Bo Xiong, and Kristen Grauman. Fusionseg: Learning to combine motion and appearance for fully automatic segmentation of generic objects in videos. In CVPR, 2017. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.571, + 0.891, + 0.595 + ], + "angle": 0, + "content": "[34] Varun Jampani, Raghudeep Gadde, and Peter V. Gehler. Video propagation networks. In CVPR, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.596, + 0.891, + 0.63 + ], + "angle": 0, + "content": "[35] Won-Dong Jang and Chang-Su Kim. Online video object segmentation via convolutional trident network. In CVPR, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.632, + 0.891, + 0.668 + ], + "angle": 0, + "content": "[36] Lei Ke, Henghui Ding, Martin Danelljan, Yu-Wing Tai, Chi-Keung Tang, and Fisher Yu. Video mask transfiner for high-quality video instance segmentation. In ECCV. Springer, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.669, + 0.891, + 0.693 + ], + "angle": 0, + "content": "[37] Lei Ke, Yu-Wing Tai, and Chi-Keung Tang. Deep occlusion-aware instance segmentation with overlapping bilayers. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.694, + 0.891, + 0.718 + ], + "angle": 0, + "content": "[38] Dahun Kim, Sanghyun Woo, Joon-Young Lee, and In So Kweon. Video panoptic segmentation. In CVPR, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.719, + 0.891, + 0.766 + ], + "angle": 0, + "content": "[39] Adam Kortylewski, Qing Liu, Angtian Wang, Yihong Sun, and Alan Yuille. Compositional convolutional neural networks: A robust and interpretable model for object recognition under occlusion. IJCV, 129(3), 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.767, + 0.891, + 0.79 + ], + "angle": 0, + "content": "[40] Zihang Lai, Erika Lu, and Weidi Xie. MAST: A memory-augmented self-supervised tracker. In CVPR, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.791, + 0.891, + 0.827 + ], + "angle": 0, + "content": "[41] Justin Lazarow, Kwonjoon Lee, Kunyu Shi, and Zhuowen Tu. Learning instance occlusion for panoptic segmentation. In CVPR, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.828, + 0.891, + 0.864 + ], + "angle": 0, + "content": "[42] Fuxin Li, Taeyoung Kim, Ahmad Humayun, David Tsai, and James M Rehg. Video segmentation by tracking many figure-ground segments. In ICCV, 2013. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.865, + 0.891, + 0.9 + ], + "angle": 0, + "content": "[43] Guanbin Li, Yuan Xie, Tianhao Wei, Keze Wang, and Liang Lin. Flow guided recurrent neural encoder for video salient object detection. In CVPR, 2018. 3" + }, + { + "type": "list", + "bbox": [ + 0.51, + 0.094, + 0.891, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "20232" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.094, + 0.468, + 0.128 + ], + "angle": 0, + "content": "[44] Haofeng Li, Guanqi Chen, Guanbin Li, and Yizhou Yu. Motion guided attention for video salient object detection. In ICCV, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.131, + 0.468, + 0.166 + ], + "angle": 0, + "content": "[45] Mingxing Li, Li Hu, Zhiwei Xiong, Bang Zhang, Pan Pan, and Dong Liu. Recurrent dynamic embedding for video object segmentation. In CVPR, 2022. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.168, + 0.468, + 0.202 + ], + "angle": 0, + "content": "[46] Siyuan Li, Martin Danelljan, Henghui Ding, Thomas E Huang, and Fisher Yu. Tracking every thing in the wild. In ECCV. Springer, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.204, + 0.468, + 0.251 + ], + "angle": 0, + "content": "[47] Xiangtai Li, Henghui Ding, Wenwei Zhang, Haobo Yuan, Jiangmiao Pang, Guangliang Cheng, Kai Chen, Ziwei Liu, and Chen Change Loy. Transformer-based visual segmentation: A survey. arXiv preprint arXiv:2304.09854, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.253, + 0.468, + 0.3 + ], + "angle": 0, + "content": "[48] Xiangtai Li, Hao He, Yibo Yang, Henghui Ding, Kuiyuan Yang, Guangliang Cheng, Yunhai Tong, and Dacheng Tao. Improving video instance segmentation via temporal pyramid routing. IEEE TPAMI, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.302, + 0.468, + 0.349 + ], + "angle": 0, + "content": "[49] Chen Liang, Yu Wu, Tianfei Zhou, Wenguan Wang, Zongxin Yang, Yunchao Wei, and Yi Yang. Rethinking cross-modal interaction from a top-down perspective for referring video object segmentation. arXiv preprint arXiv:2106.01061, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.351, + 0.468, + 0.386 + ], + "angle": 0, + "content": "[50] Fanchao Lin, Hongtao Xie, Yan Li, and Yongdong Zhang. Query-memory re-aggregation for weakly-supervised video object segmentation. In AAAI, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.387, + 0.468, + 0.411 + ], + "angle": 0, + "content": "[51] Huaijia Lin, Xiaojuan Qi, and Jiaya Jia. Agss-vos: Attention guided single-shot video object segmentation. In CVPR, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.412, + 0.468, + 0.447 + ], + "angle": 0, + "content": "[52] Tsung-Yi Lin, Michael Maire, Serge J Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In ECCV, 2014. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.449, + 0.468, + 0.495 + ], + "angle": 0, + "content": "[53] Zhihui Lin, Tianyu Yang, Maomao Li, Ziyu Wang, Chun Yuan, Wenhao Jiang, and Wei Liu. Swem: Towards real-time video object segmentation with sequential weighted expectation-maximization. In CVPR, 2022. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.497, + 0.468, + 0.533 + ], + "angle": 0, + "content": "[54] Daizong Liu, Dongdong Yu, Changhu Wang, and Pan Zhou. F2net: Learning to focus on the foreground for unsupervised video object segmentation. In AAAI, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.535, + 0.468, + 0.558 + ], + "angle": 0, + "content": "[55] Qiankun Liu, Qi Chu, Bin Liu, and Nenghai Yu. Gsm: Graph similarity model for multi-object tracking. In IJCAI, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.559, + 0.468, + 0.594 + ], + "angle": 0, + "content": "[56] Si Liu, Tianrui Hui, Shaofei Huang, Yunchao Wei, Bo Li, and Guanbin Li. Cross-modal progressive comprehension for referring segmentation. IEEE TPAMI, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.596, + 0.468, + 0.629 + ], + "angle": 0, + "content": "[57] Jonathan Long, Evan Shelhamer, and Trevor Darrell. Fully convolutional networks for semantic segmentation. In CVPR, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.632, + 0.468, + 0.667 + ], + "angle": 0, + "content": "[58] Xinkai Lu, Wenguan Wang, Martin Danelljan, Tianfei Zhou, Jianbing Shen, and Luc Van Gool. Video object segmentation with episodic graph memory networks. In ECCV, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.669, + 0.468, + 0.716 + ], + "angle": 0, + "content": "[59] Xiankai Lu, Wenguan Wang, Chao Ma, Jianbing Shen, Ling Shao, and Fatih Porikli. See more, know more: Unsupervised video object segmentation with co-attention siamese networks. In CVPR, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.718, + 0.468, + 0.752 + ], + "angle": 0, + "content": "[60] Xiankai Lu, Wenguan Wang, Jianbing Shen, David Crandall, and Luc Van Gool. Segmenting objects from relational visual data. IEEE TPAMI, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.755, + 0.468, + 0.789 + ], + "angle": 0, + "content": "[61] Xiankai Lu, Wenguan Wang, Jianbing Shen, Yu-Wing Tai, David J Crandall, and Steven CH Hoi. Learning video object segmentation from unlabeled videos. In CVPR, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.791, + 0.468, + 0.826 + ], + "angle": 0, + "content": "[62] David R Martin, Charless C Fowlkes, and Jitendra Malik. Learning to detect natural image boundaries using local brightness, color, and texture cues. IEEE TPAMI, 26(5), 2004. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.828, + 0.468, + 0.863 + ], + "angle": 0, + "content": "[63] Bo Miao, Mohammed Bennamoun, Yongsheng Gao, and Ajmal Mian. Region aware video object segmentation with deep motion modeling. arXiv preprint arXiv:2207.10258, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.865, + 0.468, + 0.899 + ], + "angle": 0, + "content": "[64] Jiaxu Miao, Xiaohan Wang, Yu Wu, Wei Li, Xu Zhang, Yunchao Wei, and Yi Yang. Large-scale video panoptic segmentation in the wild: A benchmark. In CVPR, 2022. 3" + }, + { + "type": "list", + "bbox": [ + 0.086, + 0.094, + 0.468, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.094, + 0.892, + 0.129 + ], + "angle": 0, + "content": "[65] Jiaxu Miao, Yunchao Wei, Yu Wu, Chen Liang, Guangrui Li, and Yi Yang. Vspw: A large-scale dataset for video scene parsing in the wild. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.132, + 0.892, + 0.166 + ], + "angle": 0, + "content": "[66] Jiaxu Miao, Yunchao Wei, and Yi Yang. Memory aggregation networks for efficient interactive video object segmentation. In CVPR, 2020. 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.169, + 0.892, + 0.203 + ], + "angle": 0, + "content": "[67] Peter Ochs, Jitendra Malik, and Thomas Brox. Segmentation of moving objects by long term video analysis. IEEE TPAMI, 36(6), 2014. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.206, + 0.892, + 0.242 + ], + "angle": 0, + "content": "[68] Seoung Wug Oh, Joon-Young Lee, Ning Xu, and Seon Joo Kim. Fast user-guided video object segmentation by interaction-and-propagation networks. In CVPR, 2019. 2, 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.244, + 0.892, + 0.278 + ], + "angle": 0, + "content": "[69] Seoung Wug Oh, Joon-Young Lee, Ning Xu, and Seon Joo Kim. Video object segmentation using space-time memory networks. In ICCV, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.281, + 0.892, + 0.316 + ], + "angle": 0, + "content": "[70] Seoung Wug Oh, Joon Young Lee, Ning Xu, and Seon Joo Kim. Video object segmentation using space-time memory networks. In ICCV, 2019. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.318, + 0.892, + 0.353 + ], + "angle": 0, + "content": "[71] Hyojin Park, Jayeon Yoo, Seohyeong Jeong, Ganesh Venkatesh, and Nojun Kwak. Learning dynamic network using a reuse gate function in semi-supervised video object segmentation. In CVPR, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.355, + 0.892, + 0.391 + ], + "angle": 0, + "content": "[72] Federico Peruzzi, Anna Khoreva, Rodrigo Benenson, Bernt Schiele, and Alexander Sorkine-Hornung. Learning video object segmentation from static images. In CVPR, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.393, + 0.892, + 0.44 + ], + "angle": 0, + "content": "[73] Federico Perazzi, Jordi Pont-Tuset, Brian McWilliams, Luc Van Gool, Markus Gross, and Alexander Sorkine-Hornung. A benchmark dataset and evaluation methodology for video object segmentation. In CVPR, 2016. 1, 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.442, + 0.892, + 0.489 + ], + "angle": 0, + "content": "[74] Jordi Pont-Tuset, Federico Perazzi, Sergi Caelles, Pablo Arbeláez, Alex Sorkine-Hornung, and Luc Van Gool. The 2017 davis challenge on video object segmentation. arXiv preprint arXiv:1704.00675, 2017. 1, 2, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.491, + 0.892, + 0.527 + ], + "angle": 0, + "content": "[75] Alessandro Prest, Christian Leistner, Javier Civera, Cordelia Schmid, and Vittorio Ferrari. Learning object class detectors from weakly annotated video. In CVPR, 2012. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.529, + 0.892, + 0.575 + ], + "angle": 0, + "content": "[76] Jiyang Qi, Yan Gao, Yao Hu, Xinggang Wang, Xiaoyu Liu, Xiang Bai, Serge Belongie, Alan Yuille, Philip HS Torr, and Song Bai. Occluded video instance segmentation: A benchmark. IJCV, 130(8), 2022. 3, 4, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.578, + 0.892, + 0.613 + ], + "angle": 0, + "content": "[77] Siyuan Qiao, Yukun Zhu, Hartwig Adam, Alan Yuille, and Liang-Chieh Chen. Vip-deeplab: Learning visual perception with depth-aware video panoptic segmentation. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.615, + 0.892, + 0.651 + ], + "angle": 0, + "content": "[78] Sucheng Ren, Wenxi Liu, Yongtuo Liu, Haoxin Chen, Guoqiang Han, and Shengfeng He. Reciprocal transformations for unsupervised video object segmentation. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.653, + 0.892, + 0.688 + ], + "angle": 0, + "content": "[79] Seonguk Seo, Joon-Young Lee, and Bohyung Han. Urvos: Unified referring video object segmentation network with a large-scale benchmark. In ECCV, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.69, + 0.892, + 0.726 + ], + "angle": 0, + "content": "[80] Guolei Sun, Yun Liu, Henghui Ding, Thomas Probst, and Luc Van Gool. Coarse-to-fine feature mining for video semantic segmentation. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.728, + 0.892, + 0.762 + ], + "angle": 0, + "content": "[81] Mingjie Sun, Jimin Xiao, Eng Gee Lim, Bingfeng Zhang, and Yao Zhao. Fast template matching and update for video object tracking and segmentation. In CVPR, 2020. 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.765, + 0.892, + 0.789 + ], + "angle": 0, + "content": "[82] Pavel Tokmakov, Karteek Alahari, and Cordelia Schmid. Learning video object segmentation with visual memory. In ICCV, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.79, + 0.892, + 0.814 + ], + "angle": 0, + "content": "[83] Pavel Tokmakov, Cordelia Schmid, and Karteek Alahari. Learning to segment moving objects. IJCV, 127(3), 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.816, + 0.892, + 0.851 + ], + "angle": 0, + "content": "[84] Carles Ventura, Miriam Bellver, Andreu Girbau, Amaia Salvador, Ferran Marques, and Xavier Giro-i Nieto. Rvos: End-to-end recurrent network for video object segmentation. In CVPR, 2019. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.853, + 0.892, + 0.899 + ], + "angle": 0, + "content": "[85] Paul Voigtlaender, Yuning Chai, Florian Schroff, Hartwig Adam, Bastian Leibe, and Liang-Chieh Chen. Feelvos: Fast end-to-end embedding learning for video object segmentation. In CVPR, 2019." + }, + { + "type": "list", + "bbox": [ + 0.51, + 0.094, + 0.892, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.946, + 0.518, + 0.957 + ], + "angle": 0, + "content": "20233" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.094, + 0.47, + 0.129 + ], + "angle": 0, + "content": "[86] Qiang Wang, Li Zhang, Luca Bertinetto, Weiming Hu, and Philip HS Torr. Fast online object tracking and segmentation: A unifying approach. In CVPR, 2019. 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.13, + 0.471, + 0.164 + ], + "angle": 0, + "content": "[87] Wenguan Wang, Xiankai Lu, Jianbing Shen, David J Crandall, and Ling Shao. Zero-shot video object segmentation via attentive graph neural networks. In ICCV, 2019. 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.085, + 0.165, + 0.47, + 0.212 + ], + "angle": 0, + "content": "[88] Wenguan Wang, Hongmei Song, Shuyang Zhao, Jianbing Shen, Sanyuan Zhao, Steven CH Ho, and Haibin Ling. Learning unsupervised video object segmentation through visual attention. In CVPR, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.213, + 0.471, + 0.249 + ], + "angle": 0, + "content": "[89] Wenguan Wang, Tianfei Zhou, Fatih Porikli, David Crandall, and Luc Van Gool. A survey on deep learning technique for video segmentation. arXiv preprint arXiv:2107.01153, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.25, + 0.471, + 0.284 + ], + "angle": 0, + "content": "[90] Xinlong Wang, Tete Xiao, Yuning Jiang, Shuai Shao, Jian Sun, and Chunhua Shen. Repulsion loss: Detecting pedestrians in a crowd. In CVPR, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.285, + 0.471, + 0.32 + ], + "angle": 0, + "content": "[91] Ziqin Wang, Jun Xu, Li Liu, Fan Zhu, and Ling Shao. Ranet: Ranking attention network for fast video object segmentation. In ICCV, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.321, + 0.471, + 0.356 + ], + "angle": 0, + "content": "[92] Sanghyun Woo, Dahun Kim, Joon-Young Lee, and In So Kweon. Learning to associate every segment for video panoptic segmentation. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.357, + 0.471, + 0.393 + ], + "angle": 0, + "content": "[93] Dongming Wu, Xingping Dong, Ling Shao, and Jianbing Shen. Multi-level representation learning with semantic alignment for referring video object segmentation. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.394, + 0.471, + 0.429 + ], + "angle": 0, + "content": "[94] Seoung Wug Oh, Joon-Young Lee, Kalyan Sunkavalli, and Seon Joo Kim. Fast video object segmentation by reference-guided mask propagation. In CVPR, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.429, + 0.471, + 0.464 + ], + "angle": 0, + "content": "[95] Huaxin Xiao, Jiashi Feng, Guosheng Lin, Yu Liu, and Maojun Zhang. Monet: Deep motion exploitation for video object segmentation. In CVPR, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.465, + 0.471, + 0.488 + ], + "angle": 0, + "content": "[96] Jiarui Xu, Yue Cao, Zheng Zhang, and Han Hu. Spatial-temporal relation networks for multi-object tracking. In ICCV, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.489, + 0.471, + 0.535 + ], + "angle": 0, + "content": "[97] Ning Xu, Linjie Yang, Yuchen Fan, Jianchao Yang, Dingcheng Yue, Yuchen Liang, Brian Price, Scott Cohen, and Thomas Huang. Youtube-vos: Sequence-to-sequence video object segmentation. In ECCV, 2018. 1, 2, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.536, + 0.471, + 0.571 + ], + "angle": 0, + "content": "[98] Shuangjie Xu, Daizong Liu, Linchao Bao, Wei Liu, and Pan Zhou. Mhp-vos: Multiple hypotheses propagation for video object segmentation. In CVPR, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.086, + 0.572, + 0.471, + 0.596 + ], + "angle": 0, + "content": "[99] Linjie Yang, Yuchen Fan, and Ning Xu. Video instance segmentation. In ICCV, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.597, + 0.47, + 0.631 + ], + "angle": 0, + "content": "[100] Yanchao Yang, Brian Lai, and Stefano Soatto. Dystab: Unsupervised object segmentation via dynamic-static bootstrapping. In CVPR, 2021. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.094, + 0.471, + 0.631 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.094, + 0.892, + 0.129 + ], + "angle": 0, + "content": "[101] Zhao Yang, Qiang Wang, Luca Bertinetto, Weiming Hu, Song Bai, and Philip HS Torr. Anchor diffusion for unsupervised video object segmentation. In ICCV, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.132, + 0.892, + 0.168 + ], + "angle": 0, + "content": "[102] Zongxin Yang, Yunchao Wei, and Yi Yang. Collaborative video object segmentation by foreground-background integration. In ECCV, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.171, + 0.892, + 0.219 + ], + "angle": 0, + "content": "[103] Zongxin Yang, Yunchao Wei, and Yi Yang. Associating objects with transformers for video object segmentation. In M. Ranzato, A. Beygelzimer, Y. Dauphin, P.S. Liang, and J. Wortman Vaughan, editors, NeurIPS, volume 34. Curran Associates, Inc., 2021. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.222, + 0.892, + 0.257 + ], + "angle": 0, + "content": "[104] Zongxin Yang and Yi Yang. Decoupling features in hierarchical propagation for video object segmentation. In NeurIPS, 2022. 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.261, + 0.892, + 0.297 + ], + "angle": 0, + "content": "[105] Linwei Ye, Mrigank Rochan, Zhi Liu, Xiaoqin Zhang, and Yang Wang. Referring segmentation in images and videos with cross-modal self-attention network. IEEE TPAMI, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.3, + 0.892, + 0.347 + ], + "angle": 0, + "content": "[106] Zhaoyuan Yin, Jia Zheng, Weixin Luo, Shenhan Qian, Hanling Zhang, and Shenghua Gao. Learning to recommend frame for interactive video object segmentation in the wild. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.349, + 0.892, + 0.396 + ], + "angle": 0, + "content": "[107] Jae Shin Yoon, François Rameau, Jun-Sik Kim, Seokju Lee, Seunghak Shin, and In So Kweon. Pixel-level matching for video object segmentation using convolutional neural networks. In ICCV, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.4, + 0.892, + 0.435 + ], + "angle": 0, + "content": "[108] Xiaohang Zhan, Xingang Pan, Bo Dai, Ziwei Liu, Dahua Lin, and Chen Change Loy. Self-supervised scene de-occlusion. In CVPR, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.439, + 0.892, + 0.474 + ], + "angle": 0, + "content": "[109] Lu Zhang, Zhe Lin, Jianming Zhang, Huchuan Lu, and You He. Fast video object segmentation via dynamic targeting network. In ICCV, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.478, + 0.892, + 0.514 + ], + "angle": 0, + "content": "[110] Shifeng Zhang, Longyin Wen, Xiao Bian, Zhen Lei, and Stan Z Li. Occlusion-aware r-cnn: Detecting pedestrians in a crowd. In ECCV, 2018.3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.517, + 0.892, + 0.552 + ], + "angle": 0, + "content": "[111] Yizhuo Zhang, Zhirong Wu, Houwen Peng, and Stephen Lin. A transductive approach for video object segmentation. In CVPR, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.556, + 0.892, + 0.592 + ], + "angle": 0, + "content": "[112] Tianfei Zhou, Shunzhou Wang, Yi Zhou, Yazhou Yao, Jianwu Li, and Ling Shao. Motion-attentive transition for zero-shot video object segmentation. In AAAI, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.595, + 0.892, + 0.631 + ], + "angle": 0, + "content": "[113] Ji Zhu, Hua Yang, Nian Liu, Minyoung Kim, Wenjun Zhang, and Ming-Hsuan Yang. Online multi-object tracking with dual matching attention networks. In ECCV, 2018. 3" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.094, + 0.892, + 0.631 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "20234" + } + ] +] \ No newline at end of file diff --git a/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/aa32c686-8817-467e-b52a-3ad29e222646_origin.pdf b/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/aa32c686-8817-467e-b52a-3ad29e222646_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..5970387ceeab157c41cbb744110490a519f6d0c7 --- /dev/null +++ b/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/aa32c686-8817-467e-b52a-3ad29e222646_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:7d9ab311bcfe834b7e6e087c0d32e45992c1e92e3284d89baf3b4d6a207f9e88 +size 2867901 diff --git a/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/full.md b/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/full.md new file mode 100644 index 0000000000000000000000000000000000000000..fe0b035cbb12b03539abe39ed0a3989f8490223b --- /dev/null +++ b/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/full.md @@ -0,0 +1,336 @@ +# MOSE: A New Dataset for Video Object Segmentation in Complex Scenes + +Henghui Ding $^{1}$ Chang Liu $^{1}$ Shuting He $^{1}$ Xudong Jiang $^{1}$ Philip H.S. Torr $^{2}$ Song Bai $^{3}$ $^{1}$ Nanyang Technological University $^{2}$ University of Oxford $^{3}$ ByteDance https://henghuiding.github.io/MOSE + +![](images/7ca00a12463ea3b973f42dc175d7440099190cdb6f711027511fb173e4c2806e.jpg) +Figure 1. Examples of video clips from the coMplex video Object SEgmentation (MOSE) dataset. The selected target objects are masked in orange. The most notable feature of MOSE is complex scenarios, including the disappearance-reappearance of objects, small/inconspicuous objects, heavy occlusions, crowded scenarios, etc. For example, the target player in the 2nd row turns around when reappearing in the 4th and 5th columns after disappearing in the 3rd column, bringing challenges in re-identifying him. Most videos in MOSE contain crowded and occluded objects with the target object seldom being the salient one. The goal of MOSE dataset is to provide a platform that promotes the development of more comprehensive and robust video object segmentation algorithms. + +# Abstract + +Video object segmentation (VOS) aims at segmenting a particular object throughout the entire video clip sequence. The state-of-the-art VOS methods have achieved excellent performance (e.g., $90 + \%$ J&F) on existing datasets. However, since the target objects in these existing datasets are usually relatively salient, dominant, and isolated, VOS under complex scenes has rarely been studied. To revisit VOS and make it more applicable in the real world, we collect a new VOS dataset called coMplex video Object SEgmentation (MOSE) to study the tracking and segmenting objects in complex scenarios. MOSE contains 2,149 video clips and 5,200 objects from 36 categories, with 431,725 high-quality object segmentation masks. The most notable feature of MOSE dataset is complex scenes with crowded and occluded objects. The target objects in the videos are commonly occluded by others and disappear in some frames. To analyze the proposed MOSE dataset, we benchmark 18 existing VOS methods under 4 different settings on the proposed MOSE dataset and conduct comprehensive comparisons. The experiments show that + +current VOS algorithms cannot well perceive objects in complex scenes. For example, under the semi-supervised VOS setting, the highest $J \& F$ by existing state-of-the-art VOS methods is only $59.4\%$ on MOSE, much lower than their $\sim 90\%$ $J \& F$ performance on DAVIS. The results reveal that although excellent performance has been achieved on existing benchmarks, there are unresolved challenges under complex scenes and more efforts are desired to explore these challenges in the future. + +# 1. Introduction + +Video object segmentation (VOS) [73, 74, 97] aims at segmenting a particular object, e.g., the dominant objects or the objects indicated by users, throughout the entire video sequence. It is one of the most fundamental and challenging computer vision tasks and has a crucial role in many piratical applications that involve video analysis and understanding, e.g., self-driving vehicle, augmented reality, video editing, etc. There are many different settings for VOS, for example, semi-supervised VOS [4, 71] that gives the first-frame mask of the target object, unsupervised VOS [14, 33] that automatically finds primary objects, and + +interactive VOS [9, 68] that relies on the user's interactions of the target object. Video object segmentation has been extensively studied in the past using traditional techniques or deep learning methods. Especially, the deep-learning-based methods have greatly improved the performance of video object segmentation and surpassed the traditional techniques by a large margin. + +Current state-of-the-art methods have achieved very high performance on two of the most commonly-used VOS datasets DAVIS [73, 74] and YouTube-VOS [97]. For example, XMem [10] achieves $92.0\%$ $\mathcal{J}\& F$ on DAVIS 2016 [73], $87.7\%$ $\mathcal{J}\& F$ on DAVIS 2017 [74], and $86.1\%$ $\mathcal{G}$ on YouTube-VOS [97]. With such a high performance, it seems that the video object segmentation has been well resolved. However, do we really perceive objects in realistic scenarios? To answer this question, we revisit video object segmentation under realistic and more complex scenes. The target objects in existing datasets [73, 74, 97] are usually salient and dominant. In real-world scenarios, isolated and salient objects rarely appear while complex and occluded scenes happen frequently. To evaluate current state-of-the-art VOS methods under more complex scenarios, we collect 2,149 videos with complex scenes and form a new large-scale challenging video object segmentation benchmark, termed coMplex video Object SEgmentation (MOSE). Specifically, there are 5,200 objects from 36 categories in MOSE, with 431,725 high-quality segmentation masks. As shown in Figure 1, the most notable feature of MOSE is complex scenarios, including disappearance-reappearance of objects, small/inconspicuous objects, heavy occlusions, crowded scenarios, etc. For example, the white sedan in the first row of Figure 1 is occluded by the bus, and the heaviest occlusion in 3rd image makes the sedan totally disappear. In the second row of Figure 1, the target player in the crowd is inconspicuous and disappears in the third frame due to the occlusions of the crowd. When the target player reappears, he turns around and shows a different appearance from the first two frames, which makes him very difficult to be tracked. The heavy occlusion and disappearance of objects under complex scenes bring great challenges to video object segmentation. We wish to promote video object segmentation research in complex environments and make VOS applicable in the real world. + +To analyze the proposed MOSE dataset, we retrain and evaluate some existing VOS methods on MOSE. Specifically, we retrain 6 state-of-the-art methods under the semi-supervised setting using mask as the first-frame reference, 2 methods under the semi-supervised setting using bounding box as the first-frame reference, 3 methods under the multi-object zero-shot video object segmentation setting, and 7 methods under interactive setting. The experimental results show that videos of complex scenes make the current + +state-of-the-art VOS methods less pronounced, especially in terms of tracking objects that disappear for a while due to occlusions. For example, the $J \& F$ performance of XMem [10] on DAVIS 2016 is $92.0\%$ but drop to $57.6\%$ on MOSE, the $J \& F$ performance of DeAOT [104] on DAVIS 2016 is $92.9\%$ but drop to $59.4\%$ on MOSE, which consistently reveal the difficulties brought by complex scenes. + +The poor performance on MOSE is due to not only occlusions/crowds/small-scale in static images but also objects' disappearance-reappearance and flickering across the temporal domain. While the heavy occlusions, crowds, and small objects bring challenges to the segmentation of objects in images, the disappearance-reappearance of objects makes it extremely difficult to track an occluded object, increasing the challenge of association. + +In a summary, our main contributions are as follows: + +- We build a new video object segmentation benchmark dataset termed MOSE (coMplex video Object SEgmentation). MOSE focuses on understanding objects in videos under complex environments. +- We conduct comprehensive comparison and evaluation of state-of-the-art VOS methods on the MOSE dataset under 4 different settings, including mask-initialization semi-supervised, box-initialization semi-supervised, unsupervised, and interactive settings. +- Taking a close look at MOSE, we analyze the challenges and potential directions for future video understanding research in complex scenes. + +# 2. Related Work + +# 2.1. Video Object Segmentation (VOS) + +Video object segmentation (VOS) aims at segmenting a particular object throughout the entire video clip sequence. According to how to indicate the particular object, there are mainly four different settings, i.e., semi-supervised VOS (or semi-automatic VOS [89] or one-shot VOS), unsupervised VOS (or automatic VOS [89] or zero-shot VOS), interactive VOS, and referring VOS. + +- Semi-supervised VOS. Semi-supervised video object segmentation (or one-shot video object segmentation) [4] gives the first frame object mask and target to segment the target object throughout the remaining video frames. Most existing works can be categorized into propagation-based methods [8, 13, 25, 30–32, 34, 35, 51, 72, 94, 95, 97, 98, 109] and matching-based methods [13, 21, 22, 29, 40, 69, 85, 91, 102, 107, 111]. The propagation-based methods utilize the mask of previous frame to guide the mask generation of the current frame, propagating the clues of target object frame by frame. The matching-based methods memorize the embedding of target object and then conduct per-pixel + +classification to measure the similarity of each pixel's feature to the embedding of target object. + +Since pixel-wise masks are hard to be obtained, some semi-supervised VOS works propose utilize bounding box as the first-frame clue to indicate the target object [50, 81, 86]. For example, SiamMask [86] applies a mask prediction branch on fully-convolutional Siamese object tracker to generate binary segmentation masks. + +- Interactive VOS. Interactive video object segmentation is a special form of semi-supervised video object segmentation [6, 9, 11, 13, 28, 66, 68, 106], it aims at segmenting the target object in a video indicated by user's interaction, e.g., clicks or scribbles. Existing interactive VOS mainly follows a paradigm of interaction-propagation way. Besides the feature encoder that extracts discriminative pixel features, there are other two modules placed on the feature encoder to achieve interactive video object segmentation, i.e., interactive segmentation module that corrects prediction based on user's interaction and mask propagation module that propagates user-corrected masks to other frames. + +- Referring VOS. Referring video object segmentation [19, 79, 105] is an emerging setting that involves multi-modal information. It gives a natural language expression to indicate the target object and aims at segmenting the target object throughout the video clips. Existing referring video object segmentation methods can be categorized into two ways: bottom-up methods and top-down methods. Bottom-up methods [20, 56, 79] directly segment the target object at the first frame and propagate the mask to the remaining frames, or conduct image segmentation on each frame independently and then associate these masks. Top-down methods [2, 49, 93] exhaustively propose all potential tracklets and select the one that is best matched with language expression as output. + +- Unsupervised VOS. It is also known as automatic VOS or zero-shot VOS [24, 44, 54, 58, 61, 78, 83, 88, 100, 101]. Different from the above VOS settings, unsupervised VOS does not require any manual clues to indicate the objects but aims to automatically find the primary objects in a video. Unsupervised VOS can only deal with objects of pre-defined categories. Early methods usually use post-processing steps [24]. Then end-to-end training methods become the mainstream in unsupervised VOS, which can be categorized into local content encoding and contextual content encoding. The local content encoding methods [14, 33, 43, 44, 82, 83, 112] typically employ two parallel networks to extract features from optical flow and RGB image. The contextual content encoding methods [59, 60, 87] focus on capturing long-term global information. + +# 2.2. Related Video Segmentation Tasks + +There are some other video segmentation tasks that are related to video object segmentation, for example, video + +instance segmentation, video semantic segmentation, and video panoptic segmentation. + +- Video Instance Segmentation (VIS). Video instance segmentation is extended from image instance segmentation by Yang et al. [99], it simultaneously conducts detection, segmentation, and tracking of instances of predefined categories in videos. Thanks to the large-scale VIS dataset YouTube-VIS [99], a series of learning methods have been developed and greatly advanced the performance of VIS [36, 48]. Then, occluded video instance segmentation is proposed by [76] to study the video instance segmentation under occluded scenes. Similar to [76], we study video understanding under complex scenarios like occlusions, but different from [76], we focus on video object segmentation (VOS) and our proposed MOSE dataset contains more videos and more complex scenes than [76], especially in terms of object's disappearance-reappearance. + +- Video Semantic Segmentation (VSS). Driven by the great success in image semantic segmentation [7, 57] and large-scale video semantic segmentation datasets [3,17,65], video semantic segmentation has drawn lots of attention and achieved significant achievement. Compared to image domain, temporal consistency and model efficiency are the new efforts in the video domain. For example, Sun et al. [80] propose Coarse-to-Fine Feature Mining (CFFM) to capture both static context and motional context. + +- Video Panoptic Segmentation (VPS). Kim et al. [38] introduce panoptic segmentation to the video domain to simultaneously segment and track both the foreground instance objects and background stuff. They build a VPS dataset with 124 videos. Then, Miao et al. [64] build a larger VPS dataset called VIPSeg with 3,536 videos. Existing methods [77, 92] mainly add temporal refinement or cross-frame association modules upon image panoptic segmentation models to enhance temporal conformity and instance tracking performance. + +# 2.3. Complex Scene Understanding + +Complex scene understanding has become a research focus in the image understanding domain [15, 18, 39, 41, 47, 63, 90, 108, 110]. For example, Ke et al. [37] propose Bilayer Convolutional Network (BCNet) to decouple overlapping objects into occluder and occludee layers. Zhang et al. [108] propose a self-supervised approach to conduct de-occlusion by ordering recovery, amodal completion, and content completion. On the video domain, however, occlusion understanding is still underexplored with only several multi-object tracking works [16, 55, 96, 113]. For example, Chu et al. [16] propose a spatial temporal attention mechanism (STAM) to capture the visible parts of targets and deal with the drift brought by occlusion. Zhu et al. [113] propose dual matching attention networks (DMAN) to deal with the noisy occlusions in multi-object tracking. Li et al. [46] propose + +Table 1. A complete list of object categories and their #instances in the MOSE dataset. The object categories are sorted in descending order of their frequency of occurrence. + +
CategoryNo.CategoryNo.CategoryNo.CategoryNo.
Person-other519Monkey181Bicycle130Boat73
Fish343Dog175Cyclist116Lizard68
Horse272Boat166Tiger108Duck64
Sheep264Sedan160Giraffe108Goose54
Zebra254Motorcyclist153Panda106Horse-rider46
Rabbit237Turtle142Driver90Bus29
Bird226Cat139Airplane89Truck15
Elephant207Parrot139Chicken86Vehicle-other14
Motorcycle192Cow139Bear84Poultry-other12
+ +to track every thing in the open world by performing class-agnostic association. In this work, we build a Complex Video Object Segmentation dataset to support future work on complex scene understanding in VOS. + +# 3. MOSE Dataset + +In this section, we introduce the newly built MOSE dataset. We first present the video collection and annotation process in Section 3.1 and then give the dataset statistics and analysis in Section 3.2. Finally, we give the evaluation metrics in Section 3.3. + +# 3.1. Video Collection and Annotation + +Video Collection. The videos in MOSE are obtained from two sources. The first source is inherited from the OVIS dataset [76], which was designed for video instance segmentation. The second source consists of newly captured videos from real-world scenarios. We chose to include videos from the OVIS dataset because they contain numerous heavy occlusions and meet the requirements of complex scenes. However, for videos inherited from OVIS, since many objects appear for the first time after the first frame, they cannot be directly used for video object segmentation, which requires a first-frame reference. One solution would be to discard all objects that do not appear in the first frame, but this would result in a significant waste of mask annotations. To make full use of OVIS videos and adapt them for video object segmentation tasks, we cut each of these videos into several videos according to the frame where each object first appears in the videos. We then discard videos that do not meet our requirements. For the newly captured videos, we first select a set of semantic categories that are common in the real world, including vehicles (e.g., bicycle, bus, airplane, boat), animals (e.g., bird, panda, dog, giraffe), and human beings in different activities (e.g., motorcycling, driving, riding, running), and + +then collect/film videos containing these categories from the campus, zoo, indoor, city street, etc. A complete list of object categories in the MOSE dataset can be seen in Table 1. These categories are common in our daily lives, where crowds and occlusions frequently occur. Moreover, they are included in popular large-scale image segmentation datasets such as MS-COCO [52], which makes it easy to use image-pretrained models. + +Our primary concern is video object segmentation under complex scenes that contain crowds, occlusion, multi-scale objects, and other challenging scenarios. Therefore, we established several rules to ensure that complex environments are included when collecting/shooting videos: + +R1. Each video must contain several objects, while videos with only a single object are excluded. Specifically, videos with crowded objects of similar appearance are highly valued. +R2. Occlusions should be present in the video. Videos that do not have any occlusions throughout the entirety of the frames are discarded. We encourage occlusions caused by other moving objects. +R3. Great emphasis should be placed on scenarios where objects disappear and then reappear due to occlusions or crowding. +R4. The target objects should be of a variety of scales and types, such as small-scale or large-scale, conspicuous or inconspicuous. +R5. Objects in the video must show sufficient motion. Videos with completely still objects or very little motion are discarded. + +Besides the rules mentioned above, we also require the video quality to be of high standard, which means the video resolution should be $1920 \times 1080$ and the video length should be between 5 to 60 seconds in general. + +Video Annotation. Having all videos for MOSE been collected, our research team looks through them and figure out a set of targets-of-interest for each of the videos. Then we slightly clip the start and the end of videos, to reduce the number of less motional or simple frames in the video. Next we annotate the first-frame mask of the target objects, as VOS input. Following this, the videos are sent to the annotation team along with the first-frame masks for annotation of the subsequent video frames. + +Using the given first-frame mask as a reference, the annotation team is required to identify the target object in the given first-frame mask, then track and annotate the segmentation mask of the target object in all frames following the first frame. The process of annotating videos has been made easier with the help of an interactive annotation tool + +Table 2. Scale comparison between MOSE and existing VOS datasets. "Annotations" denotes the number of annotated object masks. "Duration" denotes the total duration (in minutes) of the annotated videos. "mBOR" denotes the mean of the Bounding-box-Occlusion Rate. "Disapp. Rate" represents the frequency of objects that disappear in at least one frame. The newly built MOSE has the longest video duration and the largest number of annotations. More importantly, the most notable feature of MOSE is that it contains lots of crowds, occlusions, and disappearance-reappearance objects, which provide much more complex scenarios for video object segmentation. + +
DatasetYearVideosCategoriesObjectsAnnotationsDurationmBORDisapp. Rate
YouTube-Objects [75]20129610961,6929.01--
SegTrack-v2 [42]20131411241,4750.590.128.3%
FBMS [67]201459161391,4657.700.0111.2%
JumpCut [23]20152214226,3313.5200%
DAVIS16 [73]201650-503,4402.88--
DAVIS17 [74]201790-20513,5435.170.0316.1%
YouTube-VOS [97]20184,453947,755197,272334.810.0513.0%
MOSE (ours)20232,149365,200431,725443.620.2341.5%
+ +that we developed. The annotation tool automatically loads videos and all target objects. Annotators use the tool to load and preview videos and first-frame masks, annotate and visualize the segmentation masks in the subsequent frames, and save them. The annotation tool also has a built-in interactive object segmentation network XMem [10], to assist annotations in producing high-quality masks. To ensure the annotation quality under complex scenes, the annotators are required to clearly track the object that disappears and reappears due to heavy occlusions and crowd. For frames in which the target object is disappeared or is fully occluded, annotators also need to confirm that the output masks of such frames shall be blank. It is a requirement that all of our videos be annotated every five frames at the very least. For the purpose of testing the frame-rate robustness of the models, some videos are annotated every frame. + +After annotation, the videos are reviewed by our verification team to ensure high-quality annotations, particularly for videos containing occlusions, crowds, or instances of objects disappearing and reappearing. + +# 3.2. Dataset Statistics + +In Table 2, we analyze the data statistics of the new MOSE dataset using previous datasets for the video object segmentation as a reference for the analysis, including JumpCut [23], SegTrack-v2 [42], YouTube-Objects [75], FBMS [67], DAVIS [73, 74], and YouTube-VOS [97]. As shown in Table 2, there are 2,149 videos and 431,725 mask annotations for 5,200 objects contained in the proposed MOSE dataset. Comparing with previous largest VOS dataset YouTube-VOS [97], MOSE has much more mask annotations, $431\mathrm{k}$ vs. $197\mathrm{k}$ . Among the 8 video object segmentation datasets that we analyzed in Table 2, MOSE has the longest video duration (433.62 minutes), which is about 100 minutes longer than the second longest dataset YouTube-VOS (334.81 minutes) and is hundreds of times + +![](images/cf719d2be994670c6bd4f8ce76077392104b0f7ca93abf561c55a34e53fcaaf0.jpg) + +![](images/fe0ee5e59a74916260329a7befe1b3c8d152ce65b64488467dcc8097ba335a9d.jpg) +Low occlusion but high BOR + +![](images/bbc3333603268f471306c414391e211cd8c05f242b8e13cfabb75f9077a4f9bd.jpg) + +![](images/7f6aba10aaf15cf0f68b780ee0202d4276a920de7b692b327e0ee9a307acc236.jpg) +High occlusion but low BOR +Figure 2. Failure cases of the BOR indicator. It can be seen from the first row of samples that they have high BOR values, but there is less or no occlusion present. Samples in the second row have very small BOR values, but there are severe occlusions in the samples. + +![](images/ca063f5210322ecc9e81080ac587d6cb62633bf61ee96ff7971c07de5dd16be1.jpg) + +![](images/38cc128101990d559111c3c1be0d8ba1af0a7af048835e019606d501b4bb0e85.jpg) + +longer than the other seven datasets. We include more long videos in the MOSE compared to previous VOS datasets to ensure that our dataset contains a diverse range of occlusion scenarios, motion scenarios, and instances of objects disappearing and reappearing. + +Disappearance and Occlusion Analysis. Previous occluded video datasets OVIS [76] defines a Bounding-box Occlusion Rate (BOR) to reflect the occlusion degree. The BOR is calculated by the Intersection-over-Union of bounding boxes in the videos. We provide the mean of BOR of all frames in Table 2. The MOSE has the largest value of mBOR, indicating the more frequency of occlusions in MOSE than previous datasets. However, we find that BOR can only roughly reflect the occlusion. It does not well reveal the degree of occlusion in the MOSE dataset and may be prone to making some mistakes in this regard. As shown in the first row of Figure 2, high BOR is observed in the three images with low occlusion or even no occlusion. In + +contrast, in the images of the second row, where there are heavily occluded objects, the BOR is low and even 0. + +Therefore, besides counting BOR, we further calculate the number of disappeared objects that disappear in at least one frame of the video, followed by the disappearance rate that reflects the frequency of disappearances, which illustrates how often the disappearance of objects occurs due to complex scenarios in a dataset. As shown in Table 2, the disappearance rate (Disapp. Rate) of MOSE stands at the highest, reaching $41.5\%$ . Meanwhile, a total of $27.0\%$ of objects in MOSE showcase the disappearance-reappearance phenomenon, meaning they completely vanish and subsequently reappear in future frames. These observations underscore the frequent and substantial occurrence of disappearance and occlusions in the proposed MOSE dataset. + +# 3.3. Evaluation Metrics + +In accordance with the previous method [73, 74], we compute the region similarity $\mathcal{J}$ and the contour accuracy $\mathcal{F}$ as evaluation metrics. Given segmentation mask predictions $\hat{M} \in \{0,1\}^{H\times W}$ and the ground-truth masks $M \in \{0,1\}^{H\times W}$ , region similarity $\mathcal{J}$ is obtained by calculating the Intersection-over-Union (IoU) of $\hat{M}$ and $M$ , + +$$ +\mathcal {J} = \frac {\hat {M} \cap M}{\hat {M} \cup M}. \tag {1} +$$ + +Then, the average region similarity $J_{mean}$ over all objects is calculated as the final region similarity result. We use $J$ to represent $J_{mean}$ for the sake of brevity. To measure the contour quality of $\hat{M}$ , contour recall $\mathbf{R}_c$ and precision $\mathrm{P}_c$ are calculated via bipartite graph matching [62]. Then, the contour accuracy $F$ is the harmonic mean of the contour recall $\mathbf{R}_c$ and precision $\mathrm{P}_c$ , i.e., + +$$ +\mathcal {F} = \frac {2 \mathrm {P} _ {c} \mathrm {R} _ {c}}{\mathrm {P} _ {c} + \mathrm {R} _ {c}}, \tag {2} +$$ + +which represents how closely the contours of predicted masks resemble the contours of ground-truth masks. The average contour accuracy $\mathcal{F}_{mean}$ over all objects is calculated as the final contour accuracy result. We use $\mathcal{F}$ to represent $\mathcal{F}_{mean}$ for the sake of brevity. Then, $J\& F = (J + F) / 2$ is used to measure the overall performance. + +# 4. Experiments + +Herein we conduct experiments and benchmarks on four different Video Object Segmentation (VOS) settings, including semi-supervised (or one-shot) VOS with mask-initialization, semi-supervised VOS with box-initialization, unsupervised (or zero-shot) VOS, and interactive VOS, to comprehensively analyze the newly built MOSE dataset. + +Implementation Details. The proposed MOSE dataset is consistent with the YouTube-VOS [97] format. We replace + +Table 3. Comparisons of state-of-the-art semi-supervised methods on the validation set. “ $\mathcal{J}$ ” and “ $\mathcal{F}$ ” denote the mean of region similarity and the mean of contour accuracy. $\mathcal{J} \& \mathcal{F}$ denotes the mean of $\mathcal{J}$ and $\mathcal{F}$ . BL30K [11] is not added during the training stage to make a fair comparison. + +
MethodPub.MOSE (ours)DAVIS17YT-VOS18
JFJ&FJ&FG
AOT [103]NeurIPS'2153.161.357.284.984.1
STCN [12]NeurIPS'2146.655.050.885.483.0
RDE [45]CVPR'2244.652.948.884.2-
SWEM [53]CVPR'2246.854.950.984.382.8
XMem [10]ECCV'2253.362.057.686.285.7
DeAOT [104]NeurIPS'2255.163.859.485.286.0
+ +the training dataset of previous methods from YouTube-VOS with our MOSE and strictly follow their training settings on YouTube-VOS [97]. We follow DAVIS [73, 74] to evaluate the performance and report the results of $\mathcal{J}_{\text{mean}}$ , $\mathcal{F}_{\text{mean}}$ , and $\mathcal{J} \& \mathcal{F}$ on the validation set of MOSE. During the training of these VOS methods, we follow their way of using image pre-trained models but do not use any additional video datasets for pretraining. + +Settings. There are 2,149 videos in the whole MOSE dataset. These videos are split into 1,507 training videos, 311 validation videos, and 331 testing videos, for model training, daily evaluation, and competition period evaluation, respectively. Each of the videos gives a first-frame mask or bounding box as the reference of the target object for the semi-supervised (one-shot) VOS setting, and first-frame scribbles for the interactive VOS setting. + +# 4.1. Semi-supervised Video Object Segmentation + +Semi-supervised video object segmentation, or one-shot video object segmentation, gives either the first frame mask or bounding box of the target object as a clue and reference. We train and evaluate the very recent 6 mask-initialization semi-supervised VOS methods and 2 box-initialization semi-supervised VOS methods built upon ResNet-50 [26] on the MOSE dataset, as shown in Table 3 and Table 4, respectively. It is our hope that the experiments will provide baselines for future semi-supervised VOS algorithms to be developed. + +Mask-initialization. This setting is a classic and currently the most popular topic for video object segmentation. A lot of excellent deep-learning-based works have been developed for this setting in the past decade and greatly improve the video object segmentation performance to a saturation level. For example, the most recent state-of-the-art method DeAOT [104] achieves $85.2\%$ $\mathcal{J}\& \mathcal{F}$ on the DAVIS 2017 [74], $86.0\%$ $\mathcal{G}$ on YouTube-VOS [97], and $92.3\%$ $\mathcal{J}\& \mathcal{F}$ on DAVIS 2016 [73], which are excellent + +Table 4. Comparisons of state-of-the-art box-initialization semi-supervised methods on the validation set. "J" and "F" denote the mean of region similarity and the mean of contour accuracy. J&F denotes the mean of $\mathcal{I}$ and $\mathcal{F}$ . + +
MethodPub.MOSE (ours)DAVIS17YT-VOS18
JFJ&FJ&FG
SiamMask [86]CVPR'1917.326.722.056.452.8
FTMU [81]CVPR'2019.128.523.870.6-
+ +performance and almost reach the ground truth. To analyze the newly built MOSE dataset and test the performance of existing methods in complex scenes, we train and evaluate these methods on MOSE. We report the results of 6 recent state-of-the-art methods on the validation set of MOSE, including AOT [103], STCN [12], RDE [45], SWEM [53], XMem [10], and DeAOT [104], as shown in Table 3. Current state-of-the-art methods only achieve the performance from $48.8\%$ $\mathcal{J}\& \mathcal{F}$ to $59.4\%$ $\mathcal{J}\& \mathcal{F}$ on the validation set of the newly proposed MOSE dataset, while their results on DAVIS 2017 [74] and YouTube-VOS [97] are usually above $80\%$ $\mathcal{J}\& \mathcal{F}$ or $\mathcal{G}$ , some of them almost reach $90\%$ $\mathcal{J}\& \mathcal{F}$ or $\mathcal{G}$ on DAVIS 2017 and YouTube-VOS. The results reveal that although we have achieved excellent VOS performance on previous benchmarks, there are unresolved challenges under complex scenes and more efforts are desired to explore these challenges in the future. Discussion about the MOSE dataset and some potential future directions are provided in Section 5. + +Box-initialization. As shown in Table 4, two semi-supervised (one-shot) VOS methods with a bounding box as the first-frame reference are trained on MOSE and evaluated on the validation set of MOSE, including SimMask [86] and FTMU [81]. Current state-of-the-art methods achieve only $22.0\%$ and $23.8\%$ $\mathcal{J}\& \mathcal{F}$ on the validation set of the newly proposed MOSE dataset, while their results on DAVIS 2017 [74] are already $70 + \%$ $\mathcal{J}\& \mathcal{F}$ . + +After careful analysis, we believe that one of the reasons for such a significant drop in performance is that there are many heavy occlusions, small-scale objects, and crowded scenarios in the videos of MOSE dataset, which make the weakly supervised segmentation of the videos much more difficult. There is a possibility that, even within the target bounding box region, the target object may not the most salient one due to heavy occlusions and crowd. The occlusion of an object can cause it to be broken up into several pieces that are not adjacent to each other, which greatly increases the difficulty of segmenting an object using a box-driven approach. + +# 4.2. Unsupervised Video Object Segmentation + +Unsupervised video object segmentation, or zero-shot video object segmentation, does not require any manual clues (e.g., mask or bounding box) as a reference to indicate + +Table 5. Comparisons of state-of-the-art multi-object zero-shot VOS methods on the validation set. "J" and "F" denote the mean of region similarity and the mean of contour accuracy. J&F denotes the mean of $\mathcal{I}$ and $\mathcal{F}$ . + +
MethodPub.MOSE (ours)DAVIS17
JFJ&FJ&F
RVOS [84]CVPR'1924.136.930.543.7
AGNN [87]ICCV'1938.648.843.761.1
STEm-Seg [1]ECCV'2043.350.546.964.7
+ +Table 6. Comparisons of state-of-the-art interactive VOS methods on the validation set. $J \& F @60s$ denotes the $J \& F$ performance reached by methods within 60 seconds interactions. + +
MethodPub.MOSE (ours) J&F@60sDAVIS17 J&F@60s
IPNet [68]CVPR'1941.278.7
STM [70]ICCV'1945.384.8
MANet [66]CVPR'2043.679.5
ATNet [27]ECCV'2044.582.7
GIS [28]CVPR'2150.286.6
MiVOS [11]CVPR'2151.488.5
STCN [12]NeurIPS'2156.888.8
+ +the objects but aims to find the primary objects in a video automatically. The mainstream of zero-shot VOS methods focuses on addressing single-object VOS. However, MOSE is a multi-object VOS dataset like DAVIS 2017 [74], thus we only benchmark multi-object zero-shot VOS methods on MOSE, e.g., STEm-Seg [1], AGNN [87], and RVOS [84]. The results are shown in Table 5. In this setting, only videos with exhaustive first-frame annotations are used. Existing methods rely on off-the-shelf image-trained instance segmentation methods, which can well detect/segment objects in the static image thanks to complex scene learning in the image domain. The performance drop is mainly due to temporal challenges. + +# 4.3. Interactive Video Object Segmentation + +Following the interactive track of DAVIS 2019 Challenge [5], we provide initial scribbles for the target object in a specific video sequence, which are used as the first interaction. The interactive video object segmentation methods are required to predict the segmentation mask for the whole video based on the first interaction. Then, by comparing predicted masks and ground truth masks across the video, corrective scribbles on the worst frame are further provided for the methods to refine the video segmentation prediction. The above step is allowed to be repeated up to 8 times with a time limitation of 30s for each object. We report the metric of $J \& F$ @60s to encourage the methods to have a good balance between speed and accuracy. As shown in Table 6, seven recent interactive video object segmentation methods are evaluated on the validation set of MOSE. + +# 5. Discussion and Future Directions + +Herein we discuss the challenges of the proposed MOSE dataset brought by complex scenes and provide some potential future directions based on the experimental results analysis of the existing methods on MOSE. + +- Stronger Association to Track Reappearing Objects. It is necessary to develop stronger association/re-identification algorithms for VOS methods in order to be able to track objects that disappear and then reappear. Especially, the most interesting thing is that we have noticed that a number of disappeared-then-reappeared objects have been reappearing with a different appearance from the time they disappeared, i.e., appearance-changing objects. For example, the target player in Figure 1 shows his back before disappearing while showing the front at reappearing. There is a great deal of difficulty in tracking with such an appearance change. + +- Video Object Segmentation of Occluded Objects. The frequent occlusions in the videos of MOSE provide data support to the research of occlusion video understanding. Tracking and segmenting an object with heavy occlusion have rarely been studied since the target objects in existing datasets are usually salient and dominant. In real-world scenarios, isolated objects rarely appear while occluded scenes occur frequently. Our human beings can well capture those occluded objects, thanks to our contextual association and reasoning ability. With the introduction of an understanding of occlusion into the process of video object segmentation, the VOS methods will become more practical for use in real-world applications. Especially, the occlusions make the box-initialization semi-supervised VOS setting more challenging in terms of segmenting an occluded object by bounding box. + +- Attention on Small & Inconspicuous Objects. Although the detection and segmentation of small objects is a hot topic in the image domain, tracking and segmenting small and inconspicuous objects in the video object segmentation domain is still to be developed. As a matter of fact, most of the existing video object segmentation methods mainly focus on tracking large and salient objects. The lack of sufficient attention to small-scale objects makes the video object segmentation methods less pronounced in practical applications that may involve target objects of varying sizes and types. There are many objects in the proposed MOSE dataset that are on a small scale and are inconspicuous in the videos, which provides a greater opportunity for the research of tracking and segmenting objects that are small and inconspicuous in realistic scenarios. + +- Tracking Objects in Crowd. One of the most notable features of the MOSE is crowded scenarios, which are common in real-world applications. There are many videos in the MOSE dataset, which contain crowd objects, such as flocks of sheep moving together, groups of cyclists racing, + +pedestrians moving on a crowded street, and etc. A scenario like this presents challenges when it comes to segmenting and tracking one object among a crowd of objects that share a similar appearance and motion to the target object with the crowd as a whole. In the image/frame domain, it is desired for video object segmentation algorithms to enhance the identification ability to distinguish between different objects with a similar appearance. What's more, in the temporal domain, it is challenging to perform the object association between the two frames with the crowd consisting of similar-looking objects. + +- Long-Term Video Segmentation: In terms of practical applications like movie editing and surveillance monitoring, long-term video understanding is much more practical than short-term video understanding. For example, the average length of videos on YouTube is around twelve minutes, which is much longer than the average length of the existing video object segmentation dataset. Although existing VOS methods provide excellent performance, they typically require a lot of computing resources, e.g., GPU memory, for storing the object features of previous frames. Due to the large computation cost, most existing VOS methods cannot well handle long videos. The average video length of the MOSE dataset is longer than existing VOS datasets, bringing more challenges and opportunities in dealing with long-term videos. It is a good and practical direction to design VOS algorithms that can deal with long videos with low computation costs while achieving high-quality segmentation results. + +# 6. Conclusion + +We build a large-scale video object segmentation dataset named MOSE to revisit and support the research of video object segmentation under complex scenes. There are 2,149 high-resolution videos in MOSE with 431,725 high-quality object masks for 5,200 objects from 36 categories. The videos in MOSE are commonly long enough to ensure diverse and sufficient occlusion, motion, and disappearance-reappearance scenarios. Based on the proposed MOSE dataset, we benchmark existing VOS methods and conduct a comprehensive comparison. We train and evaluate six methods under the semi-supervised (one-shot) setting with a mask as the first-frame reference, two methods with a bounding box as the first-frame reference, three methods under the unsupervised (zero-shot) setting, and seven methods under the interactive setting. After evaluating existing VOS methods on MOSE dataset and comprehensively analyzing the results, some challenges and potential directions for future VOS research are concluded. We find that we are still at a nascent stage of segmenting and tracking objects in complex scenes where crowds, disappearing, occlusions, and inconspicuous/small objects occur frequently. + +# References + +[1] Ali Athar, Sabarinath Mahadevan, Aljosa Osep, Laura Leal-Taixe, and Bastian Leibe. Stem-seg: Spatio-temporal embeddings for instance segmentation in videos. In ECCV, 2020. 7 +[2] Adam Botach, Evgenii Zheltonozhskii, and Chaim Baskin. End-to-end referring video object segmentation with multimodal transformers. In CVPR, 2022. 3 +[3] Gabriel J Brostow, Julien Fauqueur, and Roberto Cipolla. Semantic object classes in video: A high-definition ground truth database. Pattern Recognition Letters, 30(2), 2009. 3 +[4] Sergi Caelles, Kevis-Kokitsi Maninis, Jordi Pont-Tuset, Laura Leal-Taixe, Daniel Cremers, and Luc Van Gool. One-shot video object segmentation. In CVPR, 2017. 1, 2 +[5] Sergi Caelles, Jordi Pont-Tuset, Federico Perazzi, Alberto Montes, Kevis-Kokitsi Maninis, and Luc Van Gool. The 2019 davis challenge on vos: Unsupervised multi-object segmentation. arXiv:1905.00737, 2019. 7 +[6] Bowen Chen, Huan Ling, Xiaohui Zeng, Gao Jun, Ziyue Xu, and Sanja Fidler. Scribblebox: Interactive annotation framework for video object segmentation. In ECCV, 2020. 3 +[7] Liang-Chieh Chen, George Papandreou, Iasonas Kokkinos, Kevin Murphy, and Alan L Yuille. Deep convolution with deep convolutional nets, atrous convolution, and fully connected crfs. IEEE TPAMI, 40(4), 2017. 3 +[8] Xi Chen, Zuoxin Li, Ye Yuan, Gang Yu, Jianxin Shen, and Donglian Qi. State-aware tracker for real-time video object segmentation. In CVPR, 2020. 2 +[9] Yuhua Chen, Jordi Pont-Tuset, Alberto Montes, and Luc Van Gool. Blazingly fast video object segmentation with pixel-wise metric learning. In CVPR, 2018. 2, 3 +[10] Ho Kei Cheng and Alexander G Schwing. Xmem: Long-term video object segmentation with an atkinson-shiffrin memory model. In ECCV. Springer, 2022. 2, 5, 6, 7 +[11] Ho Kei Cheng, Yu-Wing Tai, and Chi-Keung Tang. Modular interactive video object segmentation: Interaction-to-mask, propagation and difference-aware fusion. In CVPR, 2021. 3, 6, 7 +[12] Ho Kei Cheng, Yu-Wing Tai, and Chi-Keung Tang. Rethinking space-time networks with improved memory coverage for efficient video object segmentation. In NeurIPS, 2021. 6, 7 +[13] Jingchun Cheng, Yi-Hsuan Tsai, Wei-Chih Hung, Shengjin Wang, and Ming-Hsuan Yang. Fast and accurate online video object segmentation via tracking parts. In CVPR, 2018. 2, 3 +[14] Jingchun Cheng, Yi-Hsuan Tsai, Shengjin Wang, and Ming-Hsuan Yang. Segflow: Joint learning for video object segmentation and optical flow. In ICCV, 2017. 1, 3 +[15] Meng-Jiun Chiou, Henghui Ding, Hanshu Yan, Changhu Wang, Roger Zimmermann, and Jiashi Feng. Recovering the unbiased scene graphs from the biased ones. In ACM MM, 2021. 3 +[16] Qi Chu, Wanli Ouyang, Hongsheng Li, Xiaogang Wang, Bin Liu, and Nenghai Yu. Online multi-object tracking using cnn-based single object tracker with spatial-temporal attention mechanism. In ICCV, 2017. 3 +[17] Marius Cordts, Mohamed Omran, Sebastian Ramos, Timo Rehfeld, Markus Enzweiler, Rodrigo Benenson, Uwe Franke, Stefan Roth, and Bernt Schiele. The cityscapes dataset for semantic urban scene understanding. In CVPR, 2016. 3 +[18] Henghui Ding, Xudong Jiang, Bing Shuai, Ai Qun Liu, and Gang Wang. Semantic segmentation with context encoding and multi-path decoding. IEEE TIP, 29, 2020. 3 +[19] Henghui Ding, Chang Liu, Shuting He, Xudong Jiang, and Chen Change Loy. MeViS: A large-scale benchmark for video segmentation with motion expressions. In ICCV, 2023. 3 +[20] Henghui Ding, Chang Liu, Suchen Wang, and Xudong Jiang. VLT: Vision-language transformer and query generation for referring segmentation. IEEE TPAMI, 2023. 3 + +[21] Kevin Duarte, Yogesh S. Rawat, and Mubarak Shah. Capsulevos: Semi-supervised video object segmentation using capsule routing. In ICCV, 2019. 2 +[22] Brendan Duke, Abdalla Ahmed, Christian Wolf, Parham Aarabi, and Graham W Taylor. Sstvos: Sparse spatiotemporal transformers for video object segmentation. In CVPR, 2021. 2 +[23] Qingnan Fan, Fan Zhong, Dani Lischinski, Daniel Cohen-Or, and Baoquan Chen. JumpCut: non-successive mask transfer and interpolation for video cutout. ACM Tran. Graphics, 34(6), 2015. 5 +[24] Katerina Fragkiadaki, Pablo Arbelaez, Panna Felsen, and Jitendra Malik. Learning to segment moving objects in videos. In CVPR, 2015. 3 +[25] Junwei Han, Le Yang, Dingwen Zhang, Xiaojun Chang, and Xiaodan Liang. Reinforcement cutting-agent learning for video object segmentation. In CVPR, 2018. 2 +[26] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, 2016. 6 +[27] Yuk Heo, Yeong Jun Koh, and Chang-Su Kim. Interactive video object segmentation using global and local transfer modules. In ECCV, 2020. 7 +[28] Yuk Heo, Yeong Jun Koh, and Chang-Su Kim. Guided interactive video object segmentation using reliability-based attention maps. In CVPR, 2021. 3, 7 +[29] Li Hu, Peng Zhang, Bang Zhang, Pan Pan, Yinghui Xu, and Rong Jin. Learning position and target consistency for memory-based video object segmentation. In CVPR, 2021. 2 +[30] Ping Hu, Gang Wang, Xiangfei Kong, Jason Kuen, and Yap-Peng Tan. Motion-guided cascaded refinement network for video object segmentation. In CVPR, 2018. 2 +[31] Xuhua Huang, Jiarui Xu, Yu-Wing Tai, and Chi-Keung Tang. Fast video object segmentation with temporal aggregation network and dynamic template matching. In CVPR, 2020. 2 +[32] Allan Jabri, Andrew Owens, and Alexei Efros. Space-time correspondence as a contrastive random walk. In NeurIPS, 2020. 2 +[33] Suyog Dutt Jain, Bo Xiong, and Kristen Grauman. Fusionseg: Learning to combine motion and appearance for fully automatic segmentation of generic objects in videos. In CVPR, 2017. 1, 3 +[34] Varun Jampani, Raghudeep Gadde, and Peter V. Gehler. Video propagation networks. In CVPR, 2017. 2 +[35] Won-Dong Jang and Chang-Su Kim. Online video object segmentation via convolutional trident network. In CVPR, 2017. 2 +[36] Lei Ke, Henghui Ding, Martin Danelljan, Yu-Wing Tai, Chi-Keung Tang, and Fisher Yu. Video mask transfiner for high-quality video instance segmentation. In ECCV. Springer, 2022. 3 +[37] Lei Ke, Yu-Wing Tai, and Chi-Keung Tang. Deep occlusion-aware instance segmentation with overlapping bilayers. In CVPR, 2021. 3 +[38] Dahun Kim, Sanghyun Woo, Joon-Young Lee, and In So Kweon. Video panoptic segmentation. In CVPR, 2020. 3 +[39] Adam Kortylewski, Qing Liu, Angtian Wang, Yihong Sun, and Alan Yuille. Compositional convolutional neural networks: A robust and interpretable model for object recognition under occlusion. IJCV, 129(3), 2021. 3 +[40] Zihang Lai, Erika Lu, and Weidi Xie. MAST: A memory-augmented self-supervised tracker. In CVPR, 2020. 2 +[41] Justin Lazarow, Kwonjoon Lee, Kunyu Shi, and Zhuowen Tu. Learning instance occlusion for panoptic segmentation. In CVPR, 2020. 3 +[42] Fuxin Li, Taeyoung Kim, Ahmad Humayun, David Tsai, and James M Rehg. Video segmentation by tracking many figure-ground segments. In ICCV, 2013. 5 +[43] Guanbin Li, Yuan Xie, Tianhao Wei, Keze Wang, and Liang Lin. Flow guided recurrent neural encoder for video salient object detection. In CVPR, 2018. 3 + +[44] Haofeng Li, Guanqi Chen, Guanbin Li, and Yizhou Yu. Motion guided attention for video salient object detection. In ICCV, 2019. 3 +[45] Mingxing Li, Li Hu, Zhiwei Xiong, Bang Zhang, Pan Pan, and Dong Liu. Recurrent dynamic embedding for video object segmentation. In CVPR, 2022. 6, 7 +[46] Siyuan Li, Martin Danelljan, Henghui Ding, Thomas E Huang, and Fisher Yu. Tracking every thing in the wild. In ECCV. Springer, 2022. 3 +[47] Xiangtai Li, Henghui Ding, Wenwei Zhang, Haobo Yuan, Jiangmiao Pang, Guangliang Cheng, Kai Chen, Ziwei Liu, and Chen Change Loy. Transformer-based visual segmentation: A survey. arXiv preprint arXiv:2304.09854, 2023. 3 +[48] Xiangtai Li, Hao He, Yibo Yang, Henghui Ding, Kuiyuan Yang, Guangliang Cheng, Yunhai Tong, and Dacheng Tao. Improving video instance segmentation via temporal pyramid routing. IEEE TPAMI, 2022. 3 +[49] Chen Liang, Yu Wu, Tianfei Zhou, Wenguan Wang, Zongxin Yang, Yunchao Wei, and Yi Yang. Rethinking cross-modal interaction from a top-down perspective for referring video object segmentation. arXiv preprint arXiv:2106.01061, 2021. 3 +[50] Fanchao Lin, Hongtao Xie, Yan Li, and Yongdong Zhang. Query-memory re-aggregation for weakly-supervised video object segmentation. In AAAI, 2021. 3 +[51] Huaijia Lin, Xiaojuan Qi, and Jiaya Jia. Agss-vos: Attention guided single-shot video object segmentation. In CVPR, 2019. 2 +[52] Tsung-Yi Lin, Michael Maire, Serge J Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In ECCV, 2014. 4 +[53] Zhihui Lin, Tianyu Yang, Maomao Li, Ziyu Wang, Chun Yuan, Wenhao Jiang, and Wei Liu. Swem: Towards real-time video object segmentation with sequential weighted expectation-maximization. In CVPR, 2022. 6, 7 +[54] Daizong Liu, Dongdong Yu, Changhu Wang, and Pan Zhou. F2net: Learning to focus on the foreground for unsupervised video object segmentation. In AAAI, 2021. 3 +[55] Qiankun Liu, Qi Chu, Bin Liu, and Nenghai Yu. Gsm: Graph similarity model for multi-object tracking. In IJCAI, 2020. 3 +[56] Si Liu, Tianrui Hui, Shaofei Huang, Yunchao Wei, Bo Li, and Guanbin Li. Cross-modal progressive comprehension for referring segmentation. IEEE TPAMI, 2021. 3 +[57] Jonathan Long, Evan Shelhamer, and Trevor Darrell. Fully convolutional networks for semantic segmentation. In CVPR, 2015. 3 +[58] Xinkai Lu, Wenguan Wang, Martin Danelljan, Tianfei Zhou, Jianbing Shen, and Luc Van Gool. Video object segmentation with episodic graph memory networks. In ECCV, 2020. 3 +[59] Xiankai Lu, Wenguan Wang, Chao Ma, Jianbing Shen, Ling Shao, and Fatih Porikli. See more, know more: Unsupervised video object segmentation with co-attention siamese networks. In CVPR, 2019. 3 +[60] Xiankai Lu, Wenguan Wang, Jianbing Shen, David Crandall, and Luc Van Gool. Segmenting objects from relational visual data. IEEE TPAMI, 2021. 3 +[61] Xiankai Lu, Wenguan Wang, Jianbing Shen, Yu-Wing Tai, David J Crandall, and Steven CH Hoi. Learning video object segmentation from unlabeled videos. In CVPR, 2020. 3 +[62] David R Martin, Charless C Fowlkes, and Jitendra Malik. Learning to detect natural image boundaries using local brightness, color, and texture cues. IEEE TPAMI, 26(5), 2004. 6 +[63] Bo Miao, Mohammed Bennamoun, Yongsheng Gao, and Ajmal Mian. Region aware video object segmentation with deep motion modeling. arXiv preprint arXiv:2207.10258, 2022. 3 +[64] Jiaxu Miao, Xiaohan Wang, Yu Wu, Wei Li, Xu Zhang, Yunchao Wei, and Yi Yang. Large-scale video panoptic segmentation in the wild: A benchmark. In CVPR, 2022. 3 + +[65] Jiaxu Miao, Yunchao Wei, Yu Wu, Chen Liang, Guangrui Li, and Yi Yang. Vspw: A large-scale dataset for video scene parsing in the wild. In CVPR, 2021. 3 +[66] Jiaxu Miao, Yunchao Wei, and Yi Yang. Memory aggregation networks for efficient interactive video object segmentation. In CVPR, 2020. 3, 7 +[67] Peter Ochs, Jitendra Malik, and Thomas Brox. Segmentation of moving objects by long term video analysis. IEEE TPAMI, 36(6), 2014. 5 +[68] Seoung Wug Oh, Joon-Young Lee, Ning Xu, and Seon Joo Kim. Fast user-guided video object segmentation by interaction-and-propagation networks. In CVPR, 2019. 2, 3, 7 +[69] Seoung Wug Oh, Joon-Young Lee, Ning Xu, and Seon Joo Kim. Video object segmentation using space-time memory networks. In ICCV, 2019. 2 +[70] Seoung Wug Oh, Joon Young Lee, Ning Xu, and Seon Joo Kim. Video object segmentation using space-time memory networks. In ICCV, 2019. 7 +[71] Hyojin Park, Jayeon Yoo, Seohyeong Jeong, Ganesh Venkatesh, and Nojun Kwak. Learning dynamic network using a reuse gate function in semi-supervised video object segmentation. In CVPR, 2021. 1 +[72] Federico Peruzzi, Anna Khoreva, Rodrigo Benenson, Bernt Schiele, and Alexander Sorkine-Hornung. Learning video object segmentation from static images. In CVPR, 2017. 2 +[73] Federico Perazzi, Jordi Pont-Tuset, Brian McWilliams, Luc Van Gool, Markus Gross, and Alexander Sorkine-Hornung. A benchmark dataset and evaluation methodology for video object segmentation. In CVPR, 2016. 1, 2, 5, 6 +[74] Jordi Pont-Tuset, Federico Perazzi, Sergi Caelles, Pablo Arbeláez, Alex Sorkine-Hornung, and Luc Van Gool. The 2017 davis challenge on video object segmentation. arXiv preprint arXiv:1704.00675, 2017. 1, 2, 5, 6, 7 +[75] Alessandro Prest, Christian Leistner, Javier Civera, Cordelia Schmid, and Vittorio Ferrari. Learning object class detectors from weakly annotated video. In CVPR, 2012. 5 +[76] Jiyang Qi, Yan Gao, Yao Hu, Xinggang Wang, Xiaoyu Liu, Xiang Bai, Serge Belongie, Alan Yuille, Philip HS Torr, and Song Bai. Occluded video instance segmentation: A benchmark. IJCV, 130(8), 2022. 3, 4, 5 +[77] Siyuan Qiao, Yukun Zhu, Hartwig Adam, Alan Yuille, and Liang-Chieh Chen. Vip-deeplab: Learning visual perception with depth-aware video panoptic segmentation. In CVPR, 2021. 3 +[78] Sucheng Ren, Wenxi Liu, Yongtuo Liu, Haoxin Chen, Guoqiang Han, and Shengfeng He. Reciprocal transformations for unsupervised video object segmentation. In CVPR, 2021. 3 +[79] Seonguk Seo, Joon-Young Lee, and Bohyung Han. Urvos: Unified referring video object segmentation network with a large-scale benchmark. In ECCV, 2020. 3 +[80] Guolei Sun, Yun Liu, Henghui Ding, Thomas Probst, and Luc Van Gool. Coarse-to-fine feature mining for video semantic segmentation. In CVPR, 2022. 3 +[81] Mingjie Sun, Jimin Xiao, Eng Gee Lim, Bingfeng Zhang, and Yao Zhao. Fast template matching and update for video object tracking and segmentation. In CVPR, 2020. 3, 7 +[82] Pavel Tokmakov, Karteek Alahari, and Cordelia Schmid. Learning video object segmentation with visual memory. In ICCV, 2017. 3 +[83] Pavel Tokmakov, Cordelia Schmid, and Karteek Alahari. Learning to segment moving objects. IJCV, 127(3), 2019. 3 +[84] Carles Ventura, Miriam Bellver, Andreu Girbau, Amaia Salvador, Ferran Marques, and Xavier Giro-i Nieto. Rvos: End-to-end recurrent network for video object segmentation. In CVPR, 2019. 7 +[85] Paul Voigtlaender, Yuning Chai, Florian Schroff, Hartwig Adam, Bastian Leibe, and Liang-Chieh Chen. Feelvos: Fast end-to-end embedding learning for video object segmentation. In CVPR, 2019. + +[86] Qiang Wang, Li Zhang, Luca Bertinetto, Weiming Hu, and Philip HS Torr. Fast online object tracking and segmentation: A unifying approach. In CVPR, 2019. 3, 7 +[87] Wenguan Wang, Xiankai Lu, Jianbing Shen, David J Crandall, and Ling Shao. Zero-shot video object segmentation via attentive graph neural networks. In ICCV, 2019. 3, 7 +[88] Wenguan Wang, Hongmei Song, Shuyang Zhao, Jianbing Shen, Sanyuan Zhao, Steven CH Ho, and Haibin Ling. Learning unsupervised video object segmentation through visual attention. In CVPR, 2019. 3 +[89] Wenguan Wang, Tianfei Zhou, Fatih Porikli, David Crandall, and Luc Van Gool. A survey on deep learning technique for video segmentation. arXiv preprint arXiv:2107.01153, 2021. 2 +[90] Xinlong Wang, Tete Xiao, Yuning Jiang, Shuai Shao, Jian Sun, and Chunhua Shen. Repulsion loss: Detecting pedestrians in a crowd. In CVPR, 2018. 3 +[91] Ziqin Wang, Jun Xu, Li Liu, Fan Zhu, and Ling Shao. Ranet: Ranking attention network for fast video object segmentation. In ICCV, 2019. 2 +[92] Sanghyun Woo, Dahun Kim, Joon-Young Lee, and In So Kweon. Learning to associate every segment for video panoptic segmentation. In CVPR, 2021. 3 +[93] Dongming Wu, Xingping Dong, Ling Shao, and Jianbing Shen. Multi-level representation learning with semantic alignment for referring video object segmentation. In CVPR, 2022. 3 +[94] Seoung Wug Oh, Joon-Young Lee, Kalyan Sunkavalli, and Seon Joo Kim. Fast video object segmentation by reference-guided mask propagation. In CVPR, 2018. 2 +[95] Huaxin Xiao, Jiashi Feng, Guosheng Lin, Yu Liu, and Maojun Zhang. Monet: Deep motion exploitation for video object segmentation. In CVPR, 2018. 2 +[96] Jiarui Xu, Yue Cao, Zheng Zhang, and Han Hu. Spatial-temporal relation networks for multi-object tracking. In ICCV, 2019. 3 +[97] Ning Xu, Linjie Yang, Yuchen Fan, Jianchao Yang, Dingcheng Yue, Yuchen Liang, Brian Price, Scott Cohen, and Thomas Huang. Youtube-vos: Sequence-to-sequence video object segmentation. In ECCV, 2018. 1, 2, 5, 6, 7 +[98] Shuangjie Xu, Daizong Liu, Linchao Bao, Wei Liu, and Pan Zhou. Mhp-vos: Multiple hypotheses propagation for video object segmentation. In CVPR, 2019. 2 +[99] Linjie Yang, Yuchen Fan, and Ning Xu. Video instance segmentation. In ICCV, 2019. 3 +[100] Yanchao Yang, Brian Lai, and Stefano Soatto. Dystab: Unsupervised object segmentation via dynamic-static bootstrapping. In CVPR, 2021. 3 + +[101] Zhao Yang, Qiang Wang, Luca Bertinetto, Weiming Hu, Song Bai, and Philip HS Torr. Anchor diffusion for unsupervised video object segmentation. In ICCV, 2019. 3 +[102] Zongxin Yang, Yunchao Wei, and Yi Yang. Collaborative video object segmentation by foreground-background integration. In ECCV, 2020. 2 +[103] Zongxin Yang, Yunchao Wei, and Yi Yang. Associating objects with transformers for video object segmentation. In M. Ranzato, A. Beygelzimer, Y. Dauphin, P.S. Liang, and J. Wortman Vaughan, editors, NeurIPS, volume 34. Curran Associates, Inc., 2021. 6, 7 +[104] Zongxin Yang and Yi Yang. Decoupling features in hierarchical propagation for video object segmentation. In NeurIPS, 2022. 2, 6, 7 +[105] Linwei Ye, Mrigank Rochan, Zhi Liu, Xiaoqin Zhang, and Yang Wang. Referring segmentation in images and videos with cross-modal self-attention network. IEEE TPAMI, 2021. 3 +[106] Zhaoyuan Yin, Jia Zheng, Weixin Luo, Shenhan Qian, Hanling Zhang, and Shenghua Gao. Learning to recommend frame for interactive video object segmentation in the wild. In CVPR, 2021. 3 +[107] Jae Shin Yoon, François Rameau, Jun-Sik Kim, Seokju Lee, Seunghak Shin, and In So Kweon. Pixel-level matching for video object segmentation using convolutional neural networks. In ICCV, 2017. 2 +[108] Xiaohang Zhan, Xingang Pan, Bo Dai, Ziwei Liu, Dahua Lin, and Chen Change Loy. Self-supervised scene de-occlusion. In CVPR, 2020. 3 +[109] Lu Zhang, Zhe Lin, Jianming Zhang, Huchuan Lu, and You He. Fast video object segmentation via dynamic targeting network. In ICCV, 2019. 2 +[110] Shifeng Zhang, Longyin Wen, Xiao Bian, Zhen Lei, and Stan Z Li. Occlusion-aware r-cnn: Detecting pedestrians in a crowd. In ECCV, 2018.3 +[111] Yizhuo Zhang, Zhirong Wu, Houwen Peng, and Stephen Lin. A transductive approach for video object segmentation. In CVPR, 2020. 2 +[112] Tianfei Zhou, Shunzhou Wang, Yi Zhou, Yazhou Yao, Jianwu Li, and Ling Shao. Motion-attentive transition for zero-shot video object segmentation. In AAAI, 2020. 3 +[113] Ji Zhu, Hua Yang, Nian Liu, Minyoung Kim, Wenjun Zhang, and Ming-Hsuan Yang. Online multi-object tracking with dual matching attention networks. In ECCV, 2018. 3 \ No newline at end of file diff --git a/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/images.zip b/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..2951bd94c96a02c9cabcaf199bf6f4e294748567 --- /dev/null +++ b/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c356e181bc5f642b2fcdf56e209fef40f539f331211fb4dacf3758772fac3578 +size 340009 diff --git a/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/layout.json b/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..f7c47588d5c655d870786ab4a522182273d7e2a0 --- /dev/null +++ b/2023/MOSE_ A New Dataset for Video Object Segmentation in Complex Scenes/layout.json @@ -0,0 +1,9890 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 68, + 103, + 525, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 103, + 525, + 121 + ], + "spans": [ + { + "bbox": [ + 68, + 103, + 525, + 121 + ], + "type": "text", + "content": "MOSE: A New Dataset for Video Object Segmentation in Complex Scenes" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "spans": [ + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "text", + "content": "Henghui Ding" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "text", + "content": " Chang Liu" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "text", + "content": " Shuting He" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "text", + "content": " Xudong Jiang" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "text", + "content": " Philip H.S. Torr" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "text", + "content": " Song Bai" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "text", + "content": "Nanyang Technological University " + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "text", + "content": "University of Oxford " + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 58, + 141, + 534, + 193 + ], + "type": "text", + "content": "ByteDance https://henghuiding.github.io/MOSE" + } + ] + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 49, + 210, + 545, + 335 + ], + "blocks": [ + { + "bbox": [ + 49, + 210, + 545, + 335 + ], + "lines": [ + { + "bbox": [ + 49, + 210, + 545, + 335 + ], + "spans": [ + { + "bbox": [ + 49, + 210, + 545, + 335 + ], + "type": "image", + "image_path": "7ca00a12463ea3b973f42dc175d7440099190cdb6f711027511fb173e4c2806e.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 337, + 546, + 403 + ], + "lines": [ + { + "bbox": [ + 46, + 337, + 546, + 403 + ], + "spans": [ + { + "bbox": [ + 46, + 337, + 546, + 403 + ], + "type": "text", + "content": "Figure 1. Examples of video clips from the coMplex video Object SEgmentation (MOSE) dataset. The selected target objects are masked in orange. The most notable feature of MOSE is complex scenarios, including the disappearance-reappearance of objects, small/inconspicuous objects, heavy occlusions, crowded scenarios, etc. For example, the target player in the 2nd row turns around when reappearing in the 4th and 5th columns after disappearing in the 3rd column, bringing challenges in re-identifying him. Most videos in MOSE contain crowded and occluded objects with the target object seldom being the salient one. The goal of MOSE dataset is to provide a platform that promotes the development of more comprehensive and robust video object segmentation algorithms." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 427, + 192, + 440 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 427, + 192, + 440 + ], + "spans": [ + { + "bbox": [ + 143, + 427, + 192, + 440 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 453, + 289, + 693 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 453, + 289, + 693 + ], + "spans": [ + { + "bbox": [ + 46, + 453, + 289, + 693 + ], + "type": "text", + "content": "Video object segmentation (VOS) aims at segmenting a particular object throughout the entire video clip sequence. The state-of-the-art VOS methods have achieved excellent performance (e.g., " + }, + { + "bbox": [ + 46, + 453, + 289, + 693 + ], + "type": "inline_equation", + "content": "90 + \\%" + }, + { + "bbox": [ + 46, + 453, + 289, + 693 + ], + "type": "text", + "content": " J&F) on existing datasets. However, since the target objects in these existing datasets are usually relatively salient, dominant, and isolated, VOS under complex scenes has rarely been studied. To revisit VOS and make it more applicable in the real world, we collect a new VOS dataset called coMplex video Object SEgmentation (MOSE) to study the tracking and segmenting objects in complex scenarios. MOSE contains 2,149 video clips and 5,200 objects from 36 categories, with 431,725 high-quality object segmentation masks. The most notable feature of MOSE dataset is complex scenes with crowded and occluded objects. The target objects in the videos are commonly occluded by others and disappear in some frames. To analyze the proposed MOSE dataset, we benchmark 18 existing VOS methods under 4 different settings on the proposed MOSE dataset and conduct comprehensive comparisons. The experiments show that" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 429, + 547, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 429, + 547, + 536 + ], + "spans": [ + { + "bbox": [ + 306, + 429, + 547, + 536 + ], + "type": "text", + "content": "current VOS algorithms cannot well perceive objects in complex scenes. For example, under the semi-supervised VOS setting, the highest " + }, + { + "bbox": [ + 306, + 429, + 547, + 536 + ], + "type": "inline_equation", + "content": "J \\& F" + }, + { + "bbox": [ + 306, + 429, + 547, + 536 + ], + "type": "text", + "content": " by existing state-of-the-art VOS methods is only " + }, + { + "bbox": [ + 306, + 429, + 547, + 536 + ], + "type": "inline_equation", + "content": "59.4\\%" + }, + { + "bbox": [ + 306, + 429, + 547, + 536 + ], + "type": "text", + "content": " on MOSE, much lower than their " + }, + { + "bbox": [ + 306, + 429, + 547, + 536 + ], + "type": "inline_equation", + "content": "\\sim 90\\%" + }, + { + "bbox": [ + 306, + 429, + 547, + 536 + ], + "type": "inline_equation", + "content": "J \\& F" + }, + { + "bbox": [ + 306, + 429, + 547, + 536 + ], + "type": "text", + "content": " performance on DAVIS. The results reveal that although excellent performance has been achieved on existing benchmarks, there are unresolved challenges under complex scenes and more efforts are desired to explore these challenges in the future." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 561, + 387, + 573 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 561, + 387, + 573 + ], + "spans": [ + { + "bbox": [ + 306, + 561, + 387, + 573 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "type": "text", + "content": "Video object segmentation (VOS) [73, 74, 97] aims at segmenting a particular object, e.g., the dominant objects or the objects indicated by users, throughout the entire video sequence. It is one of the most fundamental and challenging computer vision tasks and has a crucial role in many piratical applications that involve video analysis and understanding, e.g., self-driving vehicle, augmented reality, video editing, etc. There are many different settings for VOS, for example, semi-supervised VOS [4, 71] that gives the first-frame mask of the target object, unsupervised VOS [14, 33] that automatically finds primary objects, and" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 61, + 703, + 158, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 703, + 158, + 713 + ], + "spans": [ + { + "bbox": [ + 61, + 703, + 158, + 713 + ], + "type": "text", + "content": "henghui.ding@gmail.com" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "20224" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 288, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 288, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 288, + 156 + ], + "type": "text", + "content": "interactive VOS [9, 68] that relies on the user's interactions of the target object. Video object segmentation has been extensively studied in the past using traditional techniques or deep learning methods. Especially, the deep-learning-based methods have greatly improved the performance of video object segmentation and surpassed the traditional techniques by a large margin." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 159, + 289, + 603 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 159, + 289, + 603 + ], + "spans": [ + { + "bbox": [ + 46, + 159, + 289, + 603 + ], + "type": "text", + "content": "Current state-of-the-art methods have achieved very high performance on two of the most commonly-used VOS datasets DAVIS [73, 74] and YouTube-VOS [97]. For example, XMem [10] achieves " + }, + { + "bbox": [ + 46, + 159, + 289, + 603 + ], + "type": "inline_equation", + "content": "92.0\\%" + }, + { + "bbox": [ + 46, + 159, + 289, + 603 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& F" + }, + { + "bbox": [ + 46, + 159, + 289, + 603 + ], + "type": "text", + "content": " on DAVIS 2016 [73], " + }, + { + "bbox": [ + 46, + 159, + 289, + 603 + ], + "type": "inline_equation", + "content": "87.7\\%" + }, + { + "bbox": [ + 46, + 159, + 289, + 603 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& F" + }, + { + "bbox": [ + 46, + 159, + 289, + 603 + ], + "type": "text", + "content": " on DAVIS 2017 [74], and " + }, + { + "bbox": [ + 46, + 159, + 289, + 603 + ], + "type": "inline_equation", + "content": "86.1\\%" + }, + { + "bbox": [ + 46, + 159, + 289, + 603 + ], + "type": "inline_equation", + "content": "\\mathcal{G}" + }, + { + "bbox": [ + 46, + 159, + 289, + 603 + ], + "type": "text", + "content": " on YouTube-VOS [97]. With such a high performance, it seems that the video object segmentation has been well resolved. However, do we really perceive objects in realistic scenarios? To answer this question, we revisit video object segmentation under realistic and more complex scenes. The target objects in existing datasets [73, 74, 97] are usually salient and dominant. In real-world scenarios, isolated and salient objects rarely appear while complex and occluded scenes happen frequently. To evaluate current state-of-the-art VOS methods under more complex scenarios, we collect 2,149 videos with complex scenes and form a new large-scale challenging video object segmentation benchmark, termed coMplex video Object SEgmentation (MOSE). Specifically, there are 5,200 objects from 36 categories in MOSE, with 431,725 high-quality segmentation masks. As shown in Figure 1, the most notable feature of MOSE is complex scenarios, including disappearance-reappearance of objects, small/inconspicuous objects, heavy occlusions, crowded scenarios, etc. For example, the white sedan in the first row of Figure 1 is occluded by the bus, and the heaviest occlusion in 3rd image makes the sedan totally disappear. In the second row of Figure 1, the target player in the crowd is inconspicuous and disappears in the third frame due to the occlusions of the crowd. When the target player reappears, he turns around and shows a different appearance from the first two frames, which makes him very difficult to be tracked. The heavy occlusion and disappearance of objects under complex scenes bring great challenges to video object segmentation. We wish to promote video object segmentation research in complex environments and make VOS applicable in the real world." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "content": "To analyze the proposed MOSE dataset, we retrain and evaluate some existing VOS methods on MOSE. Specifically, we retrain 6 state-of-the-art methods under the semi-supervised setting using mask as the first-frame reference, 2 methods under the semi-supervised setting using bounding box as the first-frame reference, 3 methods under the multi-object zero-shot video object segmentation setting, and 7 methods under interactive setting. The experimental results show that videos of complex scenes make the current" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": "state-of-the-art VOS methods less pronounced, especially in terms of tracking objects that disappear for a while due to occlusions. For example, the " + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "J \\& F" + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": " performance of XMem [10] on DAVIS 2016 is " + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "92.0\\%" + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": " but drop to " + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "57.6\\%" + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": " on MOSE, the " + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "J \\& F" + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": " performance of DeAOT [104] on DAVIS 2016 is " + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "92.9\\%" + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": " but drop to " + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "59.4\\%" + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": " on MOSE, which consistently reveal the difficulties brought by complex scenes." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 304, + 157, + 545, + 252 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 157, + 545, + 252 + ], + "spans": [ + { + "bbox": [ + 304, + 157, + 545, + 252 + ], + "type": "text", + "content": "The poor performance on MOSE is due to not only occlusions/crowds/small-scale in static images but also objects' disappearance-reappearance and flickering across the temporal domain. While the heavy occlusions, crowds, and small objects bring challenges to the segmentation of objects in images, the disappearance-reappearance of objects makes it extremely difficult to track an occluded object, increasing the challenge of association." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 317, + 253, + 531, + 265 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 253, + 531, + 265 + ], + "spans": [ + { + "bbox": [ + 317, + 253, + 531, + 265 + ], + "type": "text", + "content": "In a summary, our main contributions are as follows:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 316, + 276, + 545, + 432 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 316, + 276, + 545, + 323 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 316, + 276, + 545, + 323 + ], + "spans": [ + { + "bbox": [ + 316, + 276, + 545, + 323 + ], + "type": "text", + "content": "- We build a new video object segmentation benchmark dataset termed MOSE (coMplex video Object SEgmentation). MOSE focuses on understanding objects in videos under complex environments." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 316, + 331, + 545, + 389 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 316, + 331, + 545, + 389 + ], + "spans": [ + { + "bbox": [ + 316, + 331, + 545, + 389 + ], + "type": "text", + "content": "- We conduct comprehensive comparison and evaluation of state-of-the-art VOS methods on the MOSE dataset under 4 different settings, including mask-initialization semi-supervised, box-initialization semi-supervised, unsupervised, and interactive settings." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 316, + 396, + 545, + 432 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 316, + 396, + 545, + 432 + ], + "spans": [ + { + "bbox": [ + 316, + 396, + 545, + 432 + ], + "type": "text", + "content": "- Taking a close look at MOSE, we analyze the challenges and potential directions for future video understanding research in complex scenes." + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 445, + 392, + 458 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 445, + 392, + 458 + ], + "spans": [ + { + "bbox": [ + 306, + 445, + 392, + 458 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 466, + 489, + 479 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 466, + 489, + 479 + ], + "spans": [ + { + "bbox": [ + 306, + 466, + 489, + 479 + ], + "type": "text", + "content": "2.1. Video Object Segmentation (VOS)" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 485, + 545, + 569 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 485, + 545, + 569 + ], + "spans": [ + { + "bbox": [ + 304, + 485, + 545, + 569 + ], + "type": "text", + "content": "Video object segmentation (VOS) aims at segmenting a particular object throughout the entire video clip sequence. According to how to indicate the particular object, there are mainly four different settings, i.e., semi-supervised VOS (or semi-automatic VOS [89] or one-shot VOS), unsupervised VOS (or automatic VOS [89] or zero-shot VOS), interactive VOS, and referring VOS." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "type": "text", + "content": "- Semi-supervised VOS. Semi-supervised video object segmentation (or one-shot video object segmentation) [4] gives the first frame object mask and target to segment the target object throughout the remaining video frames. Most existing works can be categorized into propagation-based methods [8, 13, 25, 30–32, 34, 35, 51, 72, 94, 95, 97, 98, 109] and matching-based methods [13, 21, 22, 29, 40, 69, 85, 91, 102, 107, 111]. The propagation-based methods utilize the mask of previous frame to guide the mask generation of the current frame, propagating the clues of target object frame by frame. The matching-based methods memorize the embedding of target object and then conduct per-pixel" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "20225" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "type": "text", + "content": "classification to measure the similarity of each pixel's feature to the embedding of target object." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 97, + 286, + 168 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 97, + 286, + 168 + ], + "spans": [ + { + "bbox": [ + 47, + 97, + 286, + 168 + ], + "type": "text", + "content": "Since pixel-wise masks are hard to be obtained, some semi-supervised VOS works propose utilize bounding box as the first-frame clue to indicate the target object [50, 81, 86]. For example, SiamMask [86] applies a mask prediction branch on fully-convolutional Siamese object tracker to generate binary segmentation masks." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 169, + 286, + 312 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 169, + 286, + 312 + ], + "spans": [ + { + "bbox": [ + 46, + 169, + 286, + 312 + ], + "type": "text", + "content": "- Interactive VOS. Interactive video object segmentation is a special form of semi-supervised video object segmentation [6, 9, 11, 13, 28, 66, 68, 106], it aims at segmenting the target object in a video indicated by user's interaction, e.g., clicks or scribbles. Existing interactive VOS mainly follows a paradigm of interaction-propagation way. Besides the feature encoder that extracts discriminative pixel features, there are other two modules placed on the feature encoder to achieve interactive video object segmentation, i.e., interactive segmentation module that corrects prediction based on user's interaction and mask propagation module that propagates user-corrected masks to other frames." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 313, + 286, + 480 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 313, + 286, + 480 + ], + "spans": [ + { + "bbox": [ + 46, + 313, + 286, + 480 + ], + "type": "text", + "content": "- Referring VOS. Referring video object segmentation [19, 79, 105] is an emerging setting that involves multi-modal information. It gives a natural language expression to indicate the target object and aims at segmenting the target object throughout the video clips. Existing referring video object segmentation methods can be categorized into two ways: bottom-up methods and top-down methods. Bottom-up methods [20, 56, 79] directly segment the target object at the first frame and propagate the mask to the remaining frames, or conduct image segmentation on each frame independently and then associate these masks. Top-down methods [2, 49, 93] exhaustively propose all potential tracklets and select the one that is best matched with language expression as output." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 481, + 286, + 661 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 481, + 286, + 661 + ], + "spans": [ + { + "bbox": [ + 46, + 481, + 286, + 661 + ], + "type": "text", + "content": "- Unsupervised VOS. It is also known as automatic VOS or zero-shot VOS [24, 44, 54, 58, 61, 78, 83, 88, 100, 101]. Different from the above VOS settings, unsupervised VOS does not require any manual clues to indicate the objects but aims to automatically find the primary objects in a video. Unsupervised VOS can only deal with objects of pre-defined categories. Early methods usually use post-processing steps [24]. Then end-to-end training methods become the mainstream in unsupervised VOS, which can be categorized into local content encoding and contextual content encoding. The local content encoding methods [14, 33, 43, 44, 82, 83, 112] typically employ two parallel networks to extract features from optical flow and RGB image. The contextual content encoding methods [59, 60, 87] focus on capturing long-term global information." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 670, + 231, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 670, + 231, + 682 + ], + "spans": [ + { + "bbox": [ + 47, + 670, + 231, + 682 + ], + "type": "text", + "content": "2.2. Related Video Segmentation Tasks" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 689, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 286, + 713 + ], + "type": "text", + "content": "There are some other video segmentation tasks that are related to video object segmentation, for example, video" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 72, + 545, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 95 + ], + "type": "text", + "content": "instance segmentation, video semantic segmentation, and video panoptic segmentation." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 97, + 545, + 276 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 97, + 545, + 276 + ], + "spans": [ + { + "bbox": [ + 304, + 97, + 545, + 276 + ], + "type": "text", + "content": "- Video Instance Segmentation (VIS). Video instance segmentation is extended from image instance segmentation by Yang et al. [99], it simultaneously conducts detection, segmentation, and tracking of instances of predefined categories in videos. Thanks to the large-scale VIS dataset YouTube-VIS [99], a series of learning methods have been developed and greatly advanced the performance of VIS [36, 48]. Then, occluded video instance segmentation is proposed by [76] to study the video instance segmentation under occluded scenes. Similar to [76], we study video understanding under complex scenarios like occlusions, but different from [76], we focus on video object segmentation (VOS) and our proposed MOSE dataset contains more videos and more complex scenes than [76], especially in terms of object's disappearance-reappearance." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 277, + 545, + 384 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 277, + 545, + 384 + ], + "spans": [ + { + "bbox": [ + 304, + 277, + 545, + 384 + ], + "type": "text", + "content": "- Video Semantic Segmentation (VSS). Driven by the great success in image semantic segmentation [7, 57] and large-scale video semantic segmentation datasets [3,17,65], video semantic segmentation has drawn lots of attention and achieved significant achievement. Compared to image domain, temporal consistency and model efficiency are the new efforts in the video domain. For example, Sun et al. [80] propose Coarse-to-Fine Feature Mining (CFFM) to capture both static context and motional context." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 385, + 545, + 504 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 385, + 545, + 504 + ], + "spans": [ + { + "bbox": [ + 304, + 385, + 545, + 504 + ], + "type": "text", + "content": "- Video Panoptic Segmentation (VPS). Kim et al. [38] introduce panoptic segmentation to the video domain to simultaneously segment and track both the foreground instance objects and background stuff. They build a VPS dataset with 124 videos. Then, Miao et al. [64] build a larger VPS dataset called VIPSeg with 3,536 videos. Existing methods [77, 92] mainly add temporal refinement or cross-frame association modules upon image panoptic segmentation models to enhance temporal conformity and instance tracking performance." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 514, + 473, + 528 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 514, + 473, + 528 + ], + "spans": [ + { + "bbox": [ + 305, + 514, + 473, + 528 + ], + "type": "text", + "content": "2.3. Complex Scene Understanding" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 534, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 534, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 534, + 545, + 713 + ], + "type": "text", + "content": "Complex scene understanding has become a research focus in the image understanding domain [15, 18, 39, 41, 47, 63, 90, 108, 110]. For example, Ke et al. [37] propose Bilayer Convolutional Network (BCNet) to decouple overlapping objects into occluder and occludee layers. Zhang et al. [108] propose a self-supervised approach to conduct de-occlusion by ordering recovery, amodal completion, and content completion. On the video domain, however, occlusion understanding is still underexplored with only several multi-object tracking works [16, 55, 96, 113]. For example, Chu et al. [16] propose a spatial temporal attention mechanism (STAM) to capture the visible parts of targets and deal with the drift brought by occlusion. Zhu et al. [113] propose dual matching attention networks (DMAN) to deal with the noisy occlusions in multi-object tracking. Li et al. [46] propose" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "text", + "content": "20226" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 113, + 287, + 247 + ], + "blocks": [ + { + "bbox": [ + 47, + 70, + 288, + 104 + ], + "lines": [ + { + "bbox": [ + 47, + 70, + 288, + 104 + ], + "spans": [ + { + "bbox": [ + 47, + 70, + 288, + 104 + ], + "type": "text", + "content": "Table 1. A complete list of object categories and their #instances in the MOSE dataset. The object categories are sorted in descending order of their frequency of occurrence." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 113, + 287, + 247 + ], + "lines": [ + { + "bbox": [ + 48, + 113, + 287, + 247 + ], + "spans": [ + { + "bbox": [ + 48, + 113, + 287, + 247 + ], + "type": "table", + "html": "
CategoryNo.CategoryNo.CategoryNo.CategoryNo.
Person-other519Monkey181Bicycle130Boat73
Fish343Dog175Cyclist116Lizard68
Horse272Boat166Tiger108Duck64
Sheep264Sedan160Giraffe108Goose54
Zebra254Motorcyclist153Panda106Horse-rider46
Rabbit237Turtle142Driver90Bus29
Bird226Cat139Airplane89Truck15
Elephant207Parrot139Chicken86Vehicle-other14
Motorcycle192Cow139Bear84Poultry-other12
", + "image_path": "3e85147504538580a3ca48f34f0f5b59211dbbae8e7cadc8cd0f5cccd64060e3.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 269, + 287, + 317 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 269, + 287, + 317 + ], + "spans": [ + { + "bbox": [ + 46, + 269, + 287, + 317 + ], + "type": "text", + "content": "to track every thing in the open world by performing class-agnostic association. In this work, we build a Complex Video Object Segmentation dataset to support future work on complex scene understanding in VOS." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 329, + 140, + 342 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 329, + 140, + 342 + ], + "spans": [ + { + "bbox": [ + 47, + 329, + 140, + 342 + ], + "type": "text", + "content": "3. MOSE Dataset" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 350, + 287, + 410 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 350, + 287, + 410 + ], + "spans": [ + { + "bbox": [ + 46, + 350, + 287, + 410 + ], + "type": "text", + "content": "In this section, we introduce the newly built MOSE dataset. We first present the video collection and annotation process in Section 3.1 and then give the dataset statistics and analysis in Section 3.2. Finally, we give the evaluation metrics in Section 3.3." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 419, + 224, + 431 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 419, + 224, + 431 + ], + "spans": [ + { + "bbox": [ + 47, + 419, + 224, + 431 + ], + "type": "text", + "content": "3.1. Video Collection and Annotation" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 437, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 437, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 437, + 288, + 715 + ], + "type": "text", + "content": "Video Collection. The videos in MOSE are obtained from two sources. The first source is inherited from the OVIS dataset [76], which was designed for video instance segmentation. The second source consists of newly captured videos from real-world scenarios. We chose to include videos from the OVIS dataset because they contain numerous heavy occlusions and meet the requirements of complex scenes. However, for videos inherited from OVIS, since many objects appear for the first time after the first frame, they cannot be directly used for video object segmentation, which requires a first-frame reference. One solution would be to discard all objects that do not appear in the first frame, but this would result in a significant waste of mask annotations. To make full use of OVIS videos and adapt them for video object segmentation tasks, we cut each of these videos into several videos according to the frame where each object first appears in the videos. We then discard videos that do not meet our requirements. For the newly captured videos, we first select a set of semantic categories that are common in the real world, including vehicles (e.g., bicycle, bus, airplane, boat), animals (e.g., bird, panda, dog, giraffe), and human beings in different activities (e.g., motorcycling, driving, riding, running), and" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 72, + 545, + 167 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 167 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 167 + ], + "type": "text", + "content": "then collect/film videos containing these categories from the campus, zoo, indoor, city street, etc. A complete list of object categories in the MOSE dataset can be seen in Table 1. These categories are common in our daily lives, where crowds and occlusions frequently occur. Moreover, they are included in popular large-scale image segmentation datasets such as MS-COCO [52], which makes it easy to use image-pretrained models." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 168, + 545, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 168, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 304, + 168, + 545, + 228 + ], + "type": "text", + "content": "Our primary concern is video object segmentation under complex scenes that contain crowds, occlusion, multi-scale objects, and other challenging scenarios. Therefore, we established several rules to ensure that complex environments are included when collecting/shooting videos:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 307, + 236, + 545, + 463 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 307, + 236, + 545, + 284 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 236, + 545, + 284 + ], + "spans": [ + { + "bbox": [ + 307, + 236, + 545, + 284 + ], + "type": "text", + "content": "R1. Each video must contain several objects, while videos with only a single object are excluded. Specifically, videos with crowded objects of similar appearance are highly valued." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 307, + 289, + 545, + 338 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 289, + 545, + 338 + ], + "spans": [ + { + "bbox": [ + 307, + 289, + 545, + 338 + ], + "type": "text", + "content": "R2. Occlusions should be present in the video. Videos that do not have any occlusions throughout the entirety of the frames are discarded. We encourage occlusions caused by other moving objects." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 307, + 343, + 545, + 380 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 343, + 545, + 380 + ], + "spans": [ + { + "bbox": [ + 307, + 343, + 545, + 380 + ], + "type": "text", + "content": "R3. Great emphasis should be placed on scenarios where objects disappear and then reappear due to occlusions or crowding." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 307, + 385, + 545, + 422 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 385, + 545, + 422 + ], + "spans": [ + { + "bbox": [ + 307, + 385, + 545, + 422 + ], + "type": "text", + "content": "R4. The target objects should be of a variety of scales and types, such as small-scale or large-scale, conspicuous or inconspicuous." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 307, + 427, + 545, + 463 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 427, + 545, + 463 + ], + "spans": [ + { + "bbox": [ + 307, + 427, + 545, + 463 + ], + "type": "text", + "content": "R5. Objects in the video must show sufficient motion. Videos with completely still objects or very little motion are discarded." + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 304, + 472, + 545, + 520 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 472, + 545, + 520 + ], + "spans": [ + { + "bbox": [ + 304, + 472, + 545, + 520 + ], + "type": "text", + "content": "Besides the rules mentioned above, we also require the video quality to be of high standard, which means the video resolution should be " + }, + { + "bbox": [ + 304, + 472, + 545, + 520 + ], + "type": "inline_equation", + "content": "1920 \\times 1080" + }, + { + "bbox": [ + 304, + 472, + 545, + 520 + ], + "type": "text", + "content": " and the video length should be between 5 to 60 seconds in general." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 533, + 545, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 545, + 641 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 545, + 641 + ], + "type": "text", + "content": "Video Annotation. Having all videos for MOSE been collected, our research team looks through them and figure out a set of targets-of-interest for each of the videos. Then we slightly clip the start and the end of videos, to reduce the number of less motional or simple frames in the video. Next we annotate the first-frame mask of the target objects, as VOS input. Following this, the videos are sent to the annotation team along with the first-frame masks for annotation of the subsequent video frames." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": "Using the given first-frame mask as a reference, the annotation team is required to identify the target object in the given first-frame mask, then track and annotate the segmentation mask of the target object in all frames following the first frame. The process of annotating videos has been made easier with the help of an interactive annotation tool" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "20227" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 54, + 130, + 541, + 254 + ], + "blocks": [ + { + "bbox": [ + 46, + 70, + 547, + 127 + ], + "lines": [ + { + "bbox": [ + 46, + 70, + 547, + 127 + ], + "spans": [ + { + "bbox": [ + 46, + 70, + 547, + 127 + ], + "type": "text", + "content": "Table 2. Scale comparison between MOSE and existing VOS datasets. \"Annotations\" denotes the number of annotated object masks. \"Duration\" denotes the total duration (in minutes) of the annotated videos. \"mBOR\" denotes the mean of the Bounding-box-Occlusion Rate. \"Disapp. Rate\" represents the frequency of objects that disappear in at least one frame. The newly built MOSE has the longest video duration and the largest number of annotations. More importantly, the most notable feature of MOSE is that it contains lots of crowds, occlusions, and disappearance-reappearance objects, which provide much more complex scenarios for video object segmentation." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 54, + 130, + 541, + 254 + ], + "lines": [ + { + "bbox": [ + 54, + 130, + 541, + 254 + ], + "spans": [ + { + "bbox": [ + 54, + 130, + 541, + 254 + ], + "type": "table", + "html": "
DatasetYearVideosCategoriesObjectsAnnotationsDurationmBORDisapp. Rate
YouTube-Objects [75]20129610961,6929.01--
SegTrack-v2 [42]20131411241,4750.590.128.3%
FBMS [67]201459161391,4657.700.0111.2%
JumpCut [23]20152214226,3313.5200%
DAVIS16 [73]201650-503,4402.88--
DAVIS17 [74]201790-20513,5435.170.0316.1%
YouTube-VOS [97]20184,453947,755197,272334.810.0513.0%
MOSE (ours)20232,149365,200431,725443.620.2341.5%
", + "image_path": "7f059f34554895f239b703d23f8225fb1879ae955b3809aa2f8fe88b922a2ba5.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 282, + 289, + 474 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 282, + 289, + 474 + ], + "spans": [ + { + "bbox": [ + 46, + 282, + 289, + 474 + ], + "type": "text", + "content": "that we developed. The annotation tool automatically loads videos and all target objects. Annotators use the tool to load and preview videos and first-frame masks, annotate and visualize the segmentation masks in the subsequent frames, and save them. The annotation tool also has a built-in interactive object segmentation network XMem [10], to assist annotations in producing high-quality masks. To ensure the annotation quality under complex scenes, the annotators are required to clearly track the object that disappears and reappears due to heavy occlusions and crowd. For frames in which the target object is disappeared or is fully occluded, annotators also need to confirm that the output masks of such frames shall be blank. It is a requirement that all of our videos be annotated every five frames at the very least. For the purpose of testing the frame-rate robustness of the models, some videos are annotated every frame." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 474, + 288, + 522 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 474, + 288, + 522 + ], + "spans": [ + { + "bbox": [ + 46, + 474, + 288, + 522 + ], + "type": "text", + "content": "After annotation, the videos are reviewed by our verification team to ensure high-quality annotations, particularly for videos containing occlusions, crowds, or instances of objects disappearing and reappearing." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 528, + 151, + 540 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 528, + 151, + 540 + ], + "spans": [ + { + "bbox": [ + 47, + 528, + 151, + 540 + ], + "type": "text", + "content": "3.2. Dataset Statistics" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 545, + 289, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 545, + 289, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 545, + 289, + 713 + ], + "type": "text", + "content": "In Table 2, we analyze the data statistics of the new MOSE dataset using previous datasets for the video object segmentation as a reference for the analysis, including JumpCut [23], SegTrack-v2 [42], YouTube-Objects [75], FBMS [67], DAVIS [73, 74], and YouTube-VOS [97]. As shown in Table 2, there are 2,149 videos and 431,725 mask annotations for 5,200 objects contained in the proposed MOSE dataset. Comparing with previous largest VOS dataset YouTube-VOS [97], MOSE has much more mask annotations, " + }, + { + "bbox": [ + 46, + 545, + 289, + 713 + ], + "type": "inline_equation", + "content": "431\\mathrm{k}" + }, + { + "bbox": [ + 46, + 545, + 289, + 713 + ], + "type": "text", + "content": " vs. " + }, + { + "bbox": [ + 46, + 545, + 289, + 713 + ], + "type": "inline_equation", + "content": "197\\mathrm{k}" + }, + { + "bbox": [ + 46, + 545, + 289, + 713 + ], + "type": "text", + "content": ". Among the 8 video object segmentation datasets that we analyzed in Table 2, MOSE has the longest video duration (433.62 minutes), which is about 100 minutes longer than the second longest dataset YouTube-VOS (334.81 minutes) and is hundreds of times" + } + ] + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 307, + 281, + 395, + 330 + ], + "blocks": [ + { + "bbox": [ + 307, + 281, + 395, + 330 + ], + "lines": [ + { + "bbox": [ + 307, + 281, + 395, + 330 + ], + "spans": [ + { + "bbox": [ + 307, + 281, + 395, + 330 + ], + "type": "image", + "image_path": "cf719d2be994670c6bd4f8ce76077392104b0f7ca93abf561c55a34e53fcaaf0.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 395, + 281, + 482, + 331 + ], + "blocks": [ + { + "bbox": [ + 395, + 281, + 482, + 331 + ], + "lines": [ + { + "bbox": [ + 395, + 281, + 482, + 331 + ], + "spans": [ + { + "bbox": [ + 395, + 281, + 482, + 331 + ], + "type": "image", + "image_path": "fe0ee5e59a74916260329a7befe1b3c8d152ce65b64488467dcc8097ba335a9d.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 383, + 331, + 469, + 340 + ], + "lines": [ + { + "bbox": [ + 383, + 331, + 469, + 340 + ], + "spans": [ + { + "bbox": [ + 383, + 331, + 469, + 340 + ], + "type": "text", + "content": "Low occlusion but high BOR" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 483, + 281, + 542, + 331 + ], + "blocks": [ + { + "bbox": [ + 483, + 281, + 542, + 331 + ], + "lines": [ + { + "bbox": [ + 483, + 281, + 542, + 331 + ], + "spans": [ + { + "bbox": [ + 483, + 281, + 542, + 331 + ], + "type": "image", + "image_path": "bbc3333603268f471306c414391e211cd8c05f242b8e13cfabb75f9077a4f9bd.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 308, + 342, + 395, + 392 + ], + "blocks": [ + { + "bbox": [ + 308, + 342, + 395, + 392 + ], + "lines": [ + { + "bbox": [ + 308, + 342, + 395, + 392 + ], + "spans": [ + { + "bbox": [ + 308, + 342, + 395, + 392 + ], + "type": "image", + "image_path": "7f6aba10aaf15cf0f68b780ee0202d4276a920de7b692b327e0ee9a307acc236.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 383, + 392, + 468, + 400 + ], + "lines": [ + { + "bbox": [ + 383, + 392, + 468, + 400 + ], + "spans": [ + { + "bbox": [ + 383, + 392, + 468, + 400 + ], + "type": "text", + "content": "High occlusion but low BOR" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 305, + 411, + 547, + 456 + ], + "lines": [ + { + "bbox": [ + 305, + 411, + 547, + 456 + ], + "spans": [ + { + "bbox": [ + 305, + 411, + 547, + 456 + ], + "type": "text", + "content": "Figure 2. Failure cases of the BOR indicator. It can be seen from the first row of samples that they have high BOR values, but there is less or no occlusion present. Samples in the second row have very small BOR values, but there are severe occlusions in the samples." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 395, + 342, + 483, + 392 + ], + "blocks": [ + { + "bbox": [ + 395, + 342, + 483, + 392 + ], + "lines": [ + { + "bbox": [ + 395, + 342, + 483, + 392 + ], + "spans": [ + { + "bbox": [ + 395, + 342, + 483, + 392 + ], + "type": "image", + "image_path": "ca063f5210322ecc9e81080ac587d6cb62633bf61ee96ff7971c07de5dd16be1.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 484, + 342, + 542, + 392 + ], + "blocks": [ + { + "bbox": [ + 484, + 342, + 542, + 392 + ], + "lines": [ + { + "bbox": [ + 484, + 342, + 542, + 392 + ], + "spans": [ + { + "bbox": [ + 484, + 342, + 542, + 392 + ], + "type": "image", + "image_path": "38cc128101990d559111c3c1be0d8ba1af0a7af048835e019606d501b4bb0e85.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 479, + 547, + 540 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 479, + 547, + 540 + ], + "spans": [ + { + "bbox": [ + 305, + 479, + 547, + 540 + ], + "type": "text", + "content": "longer than the other seven datasets. We include more long videos in the MOSE compared to previous VOS datasets to ensure that our dataset contains a diverse range of occlusion scenarios, motion scenarios, and instances of objects disappearing and reappearing." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 558, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 547, + 713 + ], + "type": "text", + "content": "Disappearance and Occlusion Analysis. Previous occluded video datasets OVIS [76] defines a Bounding-box Occlusion Rate (BOR) to reflect the occlusion degree. The BOR is calculated by the Intersection-over-Union of bounding boxes in the videos. We provide the mean of BOR of all frames in Table 2. The MOSE has the largest value of mBOR, indicating the more frequency of occlusions in MOSE than previous datasets. However, we find that BOR can only roughly reflect the occlusion. It does not well reveal the degree of occlusion in the MOSE dataset and may be prone to making some mistakes in this regard. As shown in the first row of Figure 2, high BOR is observed in the three images with low occlusion or even no occlusion. In" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "20228" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 95 + ], + "type": "text", + "content": "contrast, in the images of the second row, where there are heavily occluded objects, the BOR is low and even 0." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 96, + 288, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 96, + 288, + 251 + ], + "spans": [ + { + "bbox": [ + 46, + 96, + 288, + 251 + ], + "type": "text", + "content": "Therefore, besides counting BOR, we further calculate the number of disappeared objects that disappear in at least one frame of the video, followed by the disappearance rate that reflects the frequency of disappearances, which illustrates how often the disappearance of objects occurs due to complex scenarios in a dataset. As shown in Table 2, the disappearance rate (Disapp. Rate) of MOSE stands at the highest, reaching " + }, + { + "bbox": [ + 46, + 96, + 288, + 251 + ], + "type": "inline_equation", + "content": "41.5\\%" + }, + { + "bbox": [ + 46, + 96, + 288, + 251 + ], + "type": "text", + "content": ". Meanwhile, a total of " + }, + { + "bbox": [ + 46, + 96, + 288, + 251 + ], + "type": "inline_equation", + "content": "27.0\\%" + }, + { + "bbox": [ + 46, + 96, + 288, + 251 + ], + "type": "text", + "content": " of objects in MOSE showcase the disappearance-reappearance phenomenon, meaning they completely vanish and subsequently reappear in future frames. These observations underscore the frequent and substantial occurrence of disappearance and occlusions in the proposed MOSE dataset." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 266, + 160, + 278 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 266, + 160, + 278 + ], + "spans": [ + { + "bbox": [ + 47, + 266, + 160, + 278 + ], + "type": "text", + "content": "3.3. Evaluation Metrics" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "spans": [ + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "text", + "content": "In accordance with the previous method [73, 74], we compute the region similarity " + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "inline_equation", + "content": "\\mathcal{J}" + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "text", + "content": " and the contour accuracy " + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "text", + "content": " as evaluation metrics. Given segmentation mask predictions " + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "inline_equation", + "content": "\\hat{M} \\in \\{0,1\\}^{H\\times W}" + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "text", + "content": " and the ground-truth masks " + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "inline_equation", + "content": "M \\in \\{0,1\\}^{H\\times W}" + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "text", + "content": ", region similarity " + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "inline_equation", + "content": "\\mathcal{J}" + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "text", + "content": " is obtained by calculating the Intersection-over-Union (IoU) of " + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "inline_equation", + "content": "\\hat{M}" + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 47, + 285, + 287, + 357 + ], + "type": "text", + "content": "," + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 138, + 364, + 287, + 388 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 138, + 364, + 287, + 388 + ], + "spans": [ + { + "bbox": [ + 138, + 364, + 287, + 388 + ], + "type": "interline_equation", + "content": "\\mathcal {J} = \\frac {\\hat {M} \\cap M}{\\hat {M} \\cup M}. \\tag {1}", + "image_path": "a1119bc4dc63111800f14b3580379a542a3b996833b868d700605359954105d8.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "spans": [ + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "text", + "content": "Then, the average region similarity " + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "inline_equation", + "content": "J_{mean}" + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "text", + "content": " over all objects is calculated as the final region similarity result. We use " + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "inline_equation", + "content": "J" + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "text", + "content": " to represent " + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "inline_equation", + "content": "J_{mean}" + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "text", + "content": " for the sake of brevity. To measure the contour quality of " + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "inline_equation", + "content": "\\hat{M}" + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "text", + "content": ", contour recall " + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "inline_equation", + "content": "\\mathbf{R}_c" + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "text", + "content": " and precision " + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "inline_equation", + "content": "\\mathrm{P}_c" + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "text", + "content": " are calculated via bipartite graph matching [62]. Then, the contour accuracy " + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "text", + "content": " is the harmonic mean of the contour recall " + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "inline_equation", + "content": "\\mathbf{R}_c" + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "text", + "content": " and precision " + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "inline_equation", + "content": "\\mathrm{P}_c" + }, + { + "bbox": [ + 46, + 390, + 287, + 475 + ], + "type": "text", + "content": ", i.e.," + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 140, + 479, + 287, + 506 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 140, + 479, + 287, + 506 + ], + "spans": [ + { + "bbox": [ + 140, + 479, + 287, + 506 + ], + "type": "interline_equation", + "content": "\\mathcal {F} = \\frac {2 \\mathrm {P} _ {c} \\mathrm {R} _ {c}}{\\mathrm {P} _ {c} + \\mathrm {R} _ {c}}, \\tag {2}", + "image_path": "1a55c820e0b3c1d5326503d937db21c8d8d8f187f26ae449f114951b08288035.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 510, + 287, + 582 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 510, + 287, + 582 + ], + "spans": [ + { + "bbox": [ + 46, + 510, + 287, + 582 + ], + "type": "text", + "content": "which represents how closely the contours of predicted masks resemble the contours of ground-truth masks. The average contour accuracy " + }, + { + "bbox": [ + 46, + 510, + 287, + 582 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_{mean}" + }, + { + "bbox": [ + 46, + 510, + 287, + 582 + ], + "type": "text", + "content": " over all objects is calculated as the final contour accuracy result. We use " + }, + { + "bbox": [ + 46, + 510, + 287, + 582 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 46, + 510, + 287, + 582 + ], + "type": "text", + "content": " to represent " + }, + { + "bbox": [ + 46, + 510, + 287, + 582 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_{mean}" + }, + { + "bbox": [ + 46, + 510, + 287, + 582 + ], + "type": "text", + "content": " for the sake of brevity. Then, " + }, + { + "bbox": [ + 46, + 510, + 287, + 582 + ], + "type": "inline_equation", + "content": "J\\& F = (J + F) / 2" + }, + { + "bbox": [ + 46, + 510, + 287, + 582 + ], + "type": "text", + "content": " is used to measure the overall performance." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 592, + 128, + 605 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 592, + 128, + 605 + ], + "spans": [ + { + "bbox": [ + 47, + 592, + 128, + 605 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 612, + 287, + 684 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 612, + 287, + 684 + ], + "spans": [ + { + "bbox": [ + 46, + 612, + 287, + 684 + ], + "type": "text", + "content": "Herein we conduct experiments and benchmarks on four different Video Object Segmentation (VOS) settings, including semi-supervised (or one-shot) VOS with mask-initialization, semi-supervised VOS with box-initialization, unsupervised (or zero-shot) VOS, and interactive VOS, to comprehensively analyze the newly built MOSE dataset." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 689, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 689, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 689, + 287, + 713 + ], + "type": "text", + "content": "Implementation Details. The proposed MOSE dataset is consistent with the YouTube-VOS [97] format. We replace" + } + ] + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 310, + 129, + 542, + 236 + ], + "blocks": [ + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "lines": [ + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "spans": [ + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "type": "text", + "content": "Table 3. Comparisons of state-of-the-art semi-supervised methods on the validation set. “" + }, + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "type": "inline_equation", + "content": "\\mathcal{J}" + }, + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "type": "text", + "content": "” and “" + }, + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "type": "text", + "content": "” denote the mean of region similarity and the mean of contour accuracy. " + }, + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "type": "inline_equation", + "content": "\\mathcal{J} \\& \\mathcal{F}" + }, + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "type": "text", + "content": " denotes the mean of " + }, + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "type": "inline_equation", + "content": "\\mathcal{J}" + }, + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 304, + 71, + 545, + 126 + ], + "type": "text", + "content": ". BL30K [11] is not added during the training stage to make a fair comparison." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 310, + 129, + 542, + 236 + ], + "lines": [ + { + "bbox": [ + 310, + 129, + 542, + 236 + ], + "spans": [ + { + "bbox": [ + 310, + 129, + 542, + 236 + ], + "type": "table", + "html": "
MethodPub.MOSE (ours)DAVIS17YT-VOS18
JFJ&FJ&FG
AOT [103]NeurIPS'2153.161.357.284.984.1
STCN [12]NeurIPS'2146.655.050.885.483.0
RDE [45]CVPR'2244.652.948.884.2-
SWEM [53]CVPR'2246.854.950.984.382.8
XMem [10]ECCV'2253.362.057.686.285.7
DeAOT [104]NeurIPS'2255.163.859.485.286.0
", + "image_path": "791580b87a82ee408dc73efe4120664c984984dad3566b71a6244a3ddd2aeb28.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_body" + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 256, + 545, + 353 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 256, + 545, + 353 + ], + "spans": [ + { + "bbox": [ + 304, + 256, + 545, + 353 + ], + "type": "text", + "content": "the training dataset of previous methods from YouTube-VOS with our MOSE and strictly follow their training settings on YouTube-VOS [97]. We follow DAVIS [73, 74] to evaluate the performance and report the results of " + }, + { + "bbox": [ + 304, + 256, + 545, + 353 + ], + "type": "inline_equation", + "content": "\\mathcal{J}_{\\text{mean}}" + }, + { + "bbox": [ + 304, + 256, + 545, + 353 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 256, + 545, + 353 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_{\\text{mean}}" + }, + { + "bbox": [ + 304, + 256, + 545, + 353 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 256, + 545, + 353 + ], + "type": "inline_equation", + "content": "\\mathcal{J} \\& \\mathcal{F}" + }, + { + "bbox": [ + 304, + 256, + 545, + 353 + ], + "type": "text", + "content": " on the validation set of MOSE. During the training of these VOS methods, we follow their way of using image pre-trained models but do not use any additional video datasets for pretraining." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 360, + 545, + 456 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 360, + 545, + 456 + ], + "spans": [ + { + "bbox": [ + 304, + 360, + 545, + 456 + ], + "type": "text", + "content": "Settings. There are 2,149 videos in the whole MOSE dataset. These videos are split into 1,507 training videos, 311 validation videos, and 331 testing videos, for model training, daily evaluation, and competition period evaluation, respectively. Each of the videos gives a first-frame mask or bounding box as the reference of the target object for the semi-supervised (one-shot) VOS setting, and first-frame scribbles for the interactive VOS setting." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 464, + 537, + 478 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 464, + 537, + 478 + ], + "spans": [ + { + "bbox": [ + 305, + 464, + 537, + 478 + ], + "type": "text", + "content": "4.1. Semi-supervised Video Object Segmentation" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 483, + 545, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 483, + 545, + 602 + ], + "spans": [ + { + "bbox": [ + 304, + 483, + 545, + 602 + ], + "type": "text", + "content": "Semi-supervised video object segmentation, or one-shot video object segmentation, gives either the first frame mask or bounding box of the target object as a clue and reference. We train and evaluate the very recent 6 mask-initialization semi-supervised VOS methods and 2 box-initialization semi-supervised VOS methods built upon ResNet-50 [26] on the MOSE dataset, as shown in Table 3 and Table 4, respectively. It is our hope that the experiments will provide baselines for future semi-supervised VOS algorithms to be developed." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "text", + "content": "Mask-initialization. This setting is a classic and currently the most popular topic for video object segmentation. A lot of excellent deep-learning-based works have been developed for this setting in the past decade and greatly improve the video object segmentation performance to a saturation level. For example, the most recent state-of-the-art method DeAOT [104] achieves " + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "inline_equation", + "content": "85.2\\%" + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "text", + "content": " on the DAVIS 2017 [74], " + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "inline_equation", + "content": "86.0\\%" + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{G}" + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "text", + "content": " on YouTube-VOS [97], and " + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "inline_equation", + "content": "92.3\\%" + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "text", + "content": " on DAVIS 2016 [73], which are excellent" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "20229" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 118, + 287, + 167 + ], + "blocks": [ + { + "bbox": [ + 47, + 70, + 288, + 115 + ], + "lines": [ + { + "bbox": [ + 47, + 70, + 288, + 115 + ], + "spans": [ + { + "bbox": [ + 47, + 70, + 288, + 115 + ], + "type": "text", + "content": "Table 4. Comparisons of state-of-the-art box-initialization semi-supervised methods on the validation set. \"J\" and \"F\" denote the mean of region similarity and the mean of contour accuracy. J&F denotes the mean of " + }, + { + "bbox": [ + 47, + 70, + 288, + 115 + ], + "type": "inline_equation", + "content": "\\mathcal{I}" + }, + { + "bbox": [ + 47, + 70, + 288, + 115 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 70, + 288, + 115 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 47, + 70, + 288, + 115 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 118, + 287, + 167 + ], + "lines": [ + { + "bbox": [ + 48, + 118, + 287, + 167 + ], + "spans": [ + { + "bbox": [ + 48, + 118, + 287, + 167 + ], + "type": "table", + "html": "
MethodPub.MOSE (ours)DAVIS17YT-VOS18
JFJ&FJ&FG
SiamMask [86]CVPR'1917.326.722.056.452.8
FTMU [81]CVPR'2019.128.523.870.6-
", + "image_path": "996cce833b94523a5ab290616fb2d204b135f5c873a3a88bb6aa73d69d1f0137.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "spans": [ + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "text", + "content": "performance and almost reach the ground truth. To analyze the newly built MOSE dataset and test the performance of existing methods in complex scenes, we train and evaluate these methods on MOSE. We report the results of 6 recent state-of-the-art methods on the validation set of MOSE, including AOT [103], STCN [12], RDE [45], SWEM [53], XMem [10], and DeAOT [104], as shown in Table 3. Current state-of-the-art methods only achieve the performance from " + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "inline_equation", + "content": "48.8\\%" + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "inline_equation", + "content": "59.4\\%" + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "text", + "content": " on the validation set of the newly proposed MOSE dataset, while their results on DAVIS 2017 [74] and YouTube-VOS [97] are usually above " + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "inline_equation", + "content": "80\\%" + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "inline_equation", + "content": "\\mathcal{G}" + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "text", + "content": ", some of them almost reach " + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "inline_equation", + "content": "90\\%" + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "inline_equation", + "content": "\\mathcal{G}" + }, + { + "bbox": [ + 46, + 179, + 289, + 407 + ], + "type": "text", + "content": " on DAVIS 2017 and YouTube-VOS. The results reveal that although we have achieved excellent VOS performance on previous benchmarks, there are unresolved challenges under complex scenes and more efforts are desired to explore these challenges in the future. Discussion about the MOSE dataset and some potential future directions are provided in Section 5." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 411, + 287, + 506 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 411, + 287, + 506 + ], + "spans": [ + { + "bbox": [ + 46, + 411, + 287, + 506 + ], + "type": "text", + "content": "Box-initialization. As shown in Table 4, two semi-supervised (one-shot) VOS methods with a bounding box as the first-frame reference are trained on MOSE and evaluated on the validation set of MOSE, including SimMask [86] and FTMU [81]. Current state-of-the-art methods achieve only " + }, + { + "bbox": [ + 46, + 411, + 287, + 506 + ], + "type": "inline_equation", + "content": "22.0\\%" + }, + { + "bbox": [ + 46, + 411, + 287, + 506 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 411, + 287, + 506 + ], + "type": "inline_equation", + "content": "23.8\\%" + }, + { + "bbox": [ + 46, + 411, + 287, + 506 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 46, + 411, + 287, + 506 + ], + "type": "text", + "content": " on the validation set of the newly proposed MOSE dataset, while their results on DAVIS 2017 [74] are already " + }, + { + "bbox": [ + 46, + 411, + 287, + 506 + ], + "type": "inline_equation", + "content": "70 + \\%" + }, + { + "bbox": [ + 46, + 411, + 287, + 506 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 46, + 411, + 287, + 506 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 506, + 288, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 506, + 288, + 651 + ], + "spans": [ + { + "bbox": [ + 46, + 506, + 288, + 651 + ], + "type": "text", + "content": "After careful analysis, we believe that one of the reasons for such a significant drop in performance is that there are many heavy occlusions, small-scale objects, and crowded scenarios in the videos of MOSE dataset, which make the weakly supervised segmentation of the videos much more difficult. There is a possibility that, even within the target bounding box region, the target object may not the most salient one due to heavy occlusions and crowd. The occlusion of an object can cause it to be broken up into several pieces that are not adjacent to each other, which greatly increases the difficulty of segmenting an object using a box-driven approach." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 658, + 264, + 672 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 658, + 264, + 672 + ], + "spans": [ + { + "bbox": [ + 47, + 658, + 264, + 672 + ], + "type": "text", + "content": "4.2. Unsupervised Video Object Segmentation" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 677, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 288, + 715 + ], + "type": "text", + "content": "Unsupervised video object segmentation, or zero-shot video object segmentation, does not require any manual clues (e.g., mask or bounding box) as a reference to indicate" + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 311, + 118, + 542, + 179 + ], + "blocks": [ + { + "bbox": [ + 304, + 70, + 545, + 114 + ], + "lines": [ + { + "bbox": [ + 304, + 70, + 545, + 114 + ], + "spans": [ + { + "bbox": [ + 304, + 70, + 545, + 114 + ], + "type": "text", + "content": "Table 5. Comparisons of state-of-the-art multi-object zero-shot VOS methods on the validation set. \"J\" and \"F\" denote the mean of region similarity and the mean of contour accuracy. J&F denotes the mean of " + }, + { + "bbox": [ + 304, + 70, + 545, + 114 + ], + "type": "inline_equation", + "content": "\\mathcal{I}" + }, + { + "bbox": [ + 304, + 70, + 545, + 114 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 70, + 545, + 114 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 304, + 70, + 545, + 114 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 311, + 118, + 542, + 179 + ], + "lines": [ + { + "bbox": [ + 311, + 118, + 542, + 179 + ], + "spans": [ + { + "bbox": [ + 311, + 118, + 542, + 179 + ], + "type": "table", + "html": "
MethodPub.MOSE (ours)DAVIS17
JFJ&FJ&F
RVOS [84]CVPR'1924.136.930.543.7
AGNN [87]ICCV'1938.648.843.761.1
STEm-Seg [1]ECCV'2043.350.546.964.7
", + "image_path": "efde568ae431f3a9054f721b91447691b323abbc6a7a5e4cc78f63b1ea910bea.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 307, + 227, + 544, + 333 + ], + "blocks": [ + { + "bbox": [ + 304, + 190, + 545, + 224 + ], + "lines": [ + { + "bbox": [ + 304, + 190, + 545, + 224 + ], + "spans": [ + { + "bbox": [ + 304, + 190, + 545, + 224 + ], + "type": "text", + "content": "Table 6. Comparisons of state-of-the-art interactive VOS methods on the validation set. " + }, + { + "bbox": [ + 304, + 190, + 545, + 224 + ], + "type": "inline_equation", + "content": "J \\& F @60s" + }, + { + "bbox": [ + 304, + 190, + 545, + 224 + ], + "type": "text", + "content": " denotes the " + }, + { + "bbox": [ + 304, + 190, + 545, + 224 + ], + "type": "inline_equation", + "content": "J \\& F" + }, + { + "bbox": [ + 304, + 190, + 545, + 224 + ], + "type": "text", + "content": " performance reached by methods within 60 seconds interactions." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 307, + 227, + 544, + 333 + ], + "lines": [ + { + "bbox": [ + 307, + 227, + 544, + 333 + ], + "spans": [ + { + "bbox": [ + 307, + 227, + 544, + 333 + ], + "type": "table", + "html": "
MethodPub.MOSE (ours) J&F@60sDAVIS17 J&F@60s
IPNet [68]CVPR'1941.278.7
STM [70]ICCV'1945.384.8
MANet [66]CVPR'2043.679.5
ATNet [27]ECCV'2044.582.7
GIS [28]CVPR'2150.286.6
MiVOS [11]CVPR'2151.488.5
STCN [12]NeurIPS'2156.888.8
", + "image_path": "8421815f2d49c00752686d60b3ace9e08678ce41e840924b094708530d1e92c1.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 348, + 545, + 506 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 348, + 545, + 506 + ], + "spans": [ + { + "bbox": [ + 304, + 348, + 545, + 506 + ], + "type": "text", + "content": "the objects but aims to find the primary objects in a video automatically. The mainstream of zero-shot VOS methods focuses on addressing single-object VOS. However, MOSE is a multi-object VOS dataset like DAVIS 2017 [74], thus we only benchmark multi-object zero-shot VOS methods on MOSE, e.g., STEm-Seg [1], AGNN [87], and RVOS [84]. The results are shown in Table 5. In this setting, only videos with exhaustive first-frame annotations are used. Existing methods rely on off-the-shelf image-trained instance segmentation methods, which can well detect/segment objects in the static image thanks to complex scene learning in the image domain. The performance drop is mainly due to temporal challenges." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 514, + 511, + 528 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 514, + 511, + 528 + ], + "spans": [ + { + "bbox": [ + 305, + 514, + 511, + 528 + ], + "type": "text", + "content": "4.3. Interactive Video Object Segmentation" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 533, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 545, + 713 + ], + "type": "text", + "content": "Following the interactive track of DAVIS 2019 Challenge [5], we provide initial scribbles for the target object in a specific video sequence, which are used as the first interaction. The interactive video object segmentation methods are required to predict the segmentation mask for the whole video based on the first interaction. Then, by comparing predicted masks and ground truth masks across the video, corrective scribbles on the worst frame are further provided for the methods to refine the video segmentation prediction. The above step is allowed to be repeated up to 8 times with a time limitation of 30s for each object. We report the metric of " + }, + { + "bbox": [ + 304, + 533, + 545, + 713 + ], + "type": "inline_equation", + "content": "J \\& F" + }, + { + "bbox": [ + 304, + 533, + 545, + 713 + ], + "type": "text", + "content": "@60s to encourage the methods to have a good balance between speed and accuracy. As shown in Table 6, seven recent interactive video object segmentation methods are evaluated on the validation set of MOSE." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "20230" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 71, + 232, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 71, + 232, + 84 + ], + "spans": [ + { + "bbox": [ + 47, + 71, + 232, + 84 + ], + "type": "text", + "content": "5. Discussion and Future Directions" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 91, + 287, + 139 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 91, + 287, + 139 + ], + "spans": [ + { + "bbox": [ + 47, + 91, + 287, + 139 + ], + "type": "text", + "content": "Herein we discuss the challenges of the proposed MOSE dataset brought by complex scenes and provide some potential future directions based on the experimental results analysis of the existing methods on MOSE." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 142, + 287, + 274 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 142, + 287, + 274 + ], + "spans": [ + { + "bbox": [ + 46, + 142, + 287, + 274 + ], + "type": "text", + "content": "- Stronger Association to Track Reappearing Objects. It is necessary to develop stronger association/re-identification algorithms for VOS methods in order to be able to track objects that disappear and then reappear. Especially, the most interesting thing is that we have noticed that a number of disappeared-then-reappeared objects have been reappearing with a different appearance from the time they disappeared, i.e., appearance-changing objects. For example, the target player in Figure 1 shows his back before disappearing while showing the front at reappearing. There is a great deal of difficulty in tracking with such an appearance change." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 276, + 287, + 468 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 276, + 287, + 468 + ], + "spans": [ + { + "bbox": [ + 46, + 276, + 287, + 468 + ], + "type": "text", + "content": "- Video Object Segmentation of Occluded Objects. The frequent occlusions in the videos of MOSE provide data support to the research of occlusion video understanding. Tracking and segmenting an object with heavy occlusion have rarely been studied since the target objects in existing datasets are usually salient and dominant. In real-world scenarios, isolated objects rarely appear while occluded scenes occur frequently. Our human beings can well capture those occluded objects, thanks to our contextual association and reasoning ability. With the introduction of an understanding of occlusion into the process of video object segmentation, the VOS methods will become more practical for use in real-world applications. Especially, the occlusions make the box-initialization semi-supervised VOS setting more challenging in terms of segmenting an occluded object by bounding box." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 472, + 287, + 650 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 472, + 287, + 650 + ], + "spans": [ + { + "bbox": [ + 46, + 472, + 287, + 650 + ], + "type": "text", + "content": "- Attention on Small & Inconspicuous Objects. Although the detection and segmentation of small objects is a hot topic in the image domain, tracking and segmenting small and inconspicuous objects in the video object segmentation domain is still to be developed. As a matter of fact, most of the existing video object segmentation methods mainly focus on tracking large and salient objects. The lack of sufficient attention to small-scale objects makes the video object segmentation methods less pronounced in practical applications that may involve target objects of varying sizes and types. There are many objects in the proposed MOSE dataset that are on a small scale and are inconspicuous in the videos, which provides a greater opportunity for the research of tracking and segmenting objects that are small and inconspicuous in realistic scenarios." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 653, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 287, + 714 + ], + "type": "text", + "content": "- Tracking Objects in Crowd. One of the most notable features of the MOSE is crowded scenarios, which are common in real-world applications. There are many videos in the MOSE dataset, which contain crowd objects, such as flocks of sheep moving together, groups of cyclists racing," + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "type": "text", + "content": "pedestrians moving on a crowded street, and etc. A scenario like this presents challenges when it comes to segmenting and tracking one object among a crowd of objects that share a similar appearance and motion to the target object with the crowd as a whole. In the image/frame domain, it is desired for video object segmentation algorithms to enhance the identification ability to distinguish between different objects with a similar appearance. What's more, in the temporal domain, it is challenging to perform the object association between the two frames with the crowd consisting of similar-looking objects." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 208, + 545, + 423 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 208, + 545, + 423 + ], + "spans": [ + { + "bbox": [ + 304, + 208, + 545, + 423 + ], + "type": "text", + "content": "- Long-Term Video Segmentation: In terms of practical applications like movie editing and surveillance monitoring, long-term video understanding is much more practical than short-term video understanding. For example, the average length of videos on YouTube is around twelve minutes, which is much longer than the average length of the existing video object segmentation dataset. Although existing VOS methods provide excellent performance, they typically require a lot of computing resources, e.g., GPU memory, for storing the object features of previous frames. Due to the large computation cost, most existing VOS methods cannot well handle long videos. The average video length of the MOSE dataset is longer than existing VOS datasets, bringing more challenges and opportunities in dealing with long-term videos. It is a good and practical direction to design VOS algorithms that can deal with long videos with low computation costs while achieving high-quality segmentation results." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 441, + 378, + 453 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 441, + 378, + 453 + ], + "spans": [ + { + "bbox": [ + 306, + 441, + 378, + 453 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 462, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 462, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 462, + 545, + 713 + ], + "type": "text", + "content": "We build a large-scale video object segmentation dataset named MOSE to revisit and support the research of video object segmentation under complex scenes. There are 2,149 high-resolution videos in MOSE with 431,725 high-quality object masks for 5,200 objects from 36 categories. The videos in MOSE are commonly long enough to ensure diverse and sufficient occlusion, motion, and disappearance-reappearance scenarios. Based on the proposed MOSE dataset, we benchmark existing VOS methods and conduct a comprehensive comparison. We train and evaluate six methods under the semi-supervised (one-shot) setting with a mask as the first-frame reference, two methods with a bounding box as the first-frame reference, three methods under the unsupervised (zero-shot) setting, and seven methods under the interactive setting. After evaluating existing VOS methods on MOSE dataset and comprehensively analyzing the results, some challenges and potential directions for future VOS research are concluded. We find that we are still at a nascent stage of segmenting and tracking objects in complex scenes where crowds, disappearing, occlusions, and inconspicuous/small objects occur frequently." + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "text", + "content": "20231" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 53, + 91, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 21, + "blocks": [ + { + "bbox": [ + 56, + 91, + 287, + 119 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 91, + 287, + 119 + ], + "spans": [ + { + "bbox": [ + 56, + 91, + 287, + 119 + ], + "type": "text", + "content": "[1] Ali Athar, Sabarinath Mahadevan, Aljosa Osep, Laura Leal-Taixe, and Bastian Leibe. Stem-seg: Spatio-temporal embeddings for instance segmentation in videos. In ECCV, 2020. 7" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 56, + 120, + 287, + 148 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 120, + 287, + 148 + ], + "spans": [ + { + "bbox": [ + 56, + 120, + 287, + 148 + ], + "type": "text", + "content": "[2] Adam Botach, Evgenii Zheltonozhskii, and Chaim Baskin. End-to-end referring video object segmentation with multimodal transformers. In CVPR, 2022. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 56, + 148, + 287, + 177 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 148, + 287, + 177 + ], + "spans": [ + { + "bbox": [ + 56, + 148, + 287, + 177 + ], + "type": "text", + "content": "[3] Gabriel J Brostow, Julien Fauqueur, and Roberto Cipolla. Semantic object classes in video: A high-definition ground truth database. Pattern Recognition Letters, 30(2), 2009. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 56, + 178, + 287, + 207 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 178, + 287, + 207 + ], + "spans": [ + { + "bbox": [ + 56, + 178, + 287, + 207 + ], + "type": "text", + "content": "[4] Sergi Caelles, Kevis-Kokitsi Maninis, Jordi Pont-Tuset, Laura Leal-Taixe, Daniel Cremers, and Luc Van Gool. One-shot video object segmentation. In CVPR, 2017. 1, 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 56, + 208, + 287, + 245 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 208, + 287, + 245 + ], + "spans": [ + { + "bbox": [ + 56, + 208, + 287, + 245 + ], + "type": "text", + "content": "[5] Sergi Caelles, Jordi Pont-Tuset, Federico Perazzi, Alberto Montes, Kevis-Kokitsi Maninis, and Luc Van Gool. The 2019 davis challenge on vos: Unsupervised multi-object segmentation. arXiv:1905.00737, 2019. 7" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 56, + 246, + 287, + 275 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 246, + 287, + 275 + ], + "spans": [ + { + "bbox": [ + 56, + 246, + 287, + 275 + ], + "type": "text", + "content": "[6] Bowen Chen, Huan Ling, Xiaohui Zeng, Gao Jun, Ziyue Xu, and Sanja Fidler. Scribblebox: Interactive annotation framework for video object segmentation. In ECCV, 2020. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 56, + 276, + 287, + 313 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 276, + 287, + 313 + ], + "spans": [ + { + "bbox": [ + 56, + 276, + 287, + 313 + ], + "type": "text", + "content": "[7] Liang-Chieh Chen, George Papandreou, Iasonas Kokkinos, Kevin Murphy, and Alan L Yuille. Deep convolution with deep convolutional nets, atrous convolution, and fully connected crfs. IEEE TPAMI, 40(4), 2017. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 56, + 315, + 287, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 315, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 56, + 315, + 287, + 342 + ], + "type": "text", + "content": "[8] Xi Chen, Zuoxin Li, Ye Yuan, Gang Yu, Jianxin Shen, and Donglian Qi. State-aware tracker for real-time video object segmentation. In CVPR, 2020. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 56, + 344, + 287, + 372 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 344, + 287, + 372 + ], + "spans": [ + { + "bbox": [ + 56, + 344, + 287, + 372 + ], + "type": "text", + "content": "[9] Yuhua Chen, Jordi Pont-Tuset, Alberto Montes, and Luc Van Gool. Blazingly fast video object segmentation with pixel-wise metric learning. In CVPR, 2018. 2, 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 373, + 287, + 402 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 373, + 287, + 402 + ], + "spans": [ + { + "bbox": [ + 53, + 373, + 287, + 402 + ], + "type": "text", + "content": "[10] Ho Kei Cheng and Alexander G Schwing. Xmem: Long-term video object segmentation with an atkinson-shiffrin memory model. In ECCV. Springer, 2022. 2, 5, 6, 7" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 53, + 402, + 287, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 402, + 287, + 430 + ], + "spans": [ + { + "bbox": [ + 53, + 402, + 287, + 430 + ], + "type": "text", + "content": "[11] Ho Kei Cheng, Yu-Wing Tai, and Chi-Keung Tang. Modular interactive video object segmentation: Interaction-to-mask, propagation and difference-aware fusion. In CVPR, 2021. 3, 6, 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 53, + 431, + 287, + 460 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 431, + 287, + 460 + ], + "spans": [ + { + "bbox": [ + 53, + 431, + 287, + 460 + ], + "type": "text", + "content": "[12] Ho Kei Cheng, Yu-Wing Tai, and Chi-Keung Tang. Rethinking space-time networks with improved memory coverage for efficient video object segmentation. In NeurIPS, 2021. 6, 7" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 53, + 460, + 287, + 489 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 460, + 287, + 489 + ], + "spans": [ + { + "bbox": [ + 53, + 460, + 287, + 489 + ], + "type": "text", + "content": "[13] Jingchun Cheng, Yi-Hsuan Tsai, Wei-Chih Hung, Shengjin Wang, and Ming-Hsuan Yang. Fast and accurate online video object segmentation via tracking parts. In CVPR, 2018. 2, 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 53, + 490, + 287, + 518 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 490, + 287, + 518 + ], + "spans": [ + { + "bbox": [ + 53, + 490, + 287, + 518 + ], + "type": "text", + "content": "[14] Jingchun Cheng, Yi-Hsuan Tsai, Shengjin Wang, and Ming-Hsuan Yang. Segflow: Joint learning for video object segmentation and optical flow. In ICCV, 2017. 1, 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 53, + 519, + 287, + 548 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 519, + 287, + 548 + ], + "spans": [ + { + "bbox": [ + 53, + 519, + 287, + 548 + ], + "type": "text", + "content": "[15] Meng-Jiun Chiou, Henghui Ding, Hanshu Yan, Changhu Wang, Roger Zimmermann, and Jiashi Feng. Recovering the unbiased scene graphs from the biased ones. In ACM MM, 2021. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 53, + 548, + 287, + 586 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 548, + 287, + 586 + ], + "spans": [ + { + "bbox": [ + 53, + 548, + 287, + 586 + ], + "type": "text", + "content": "[16] Qi Chu, Wanli Ouyang, Hongsheng Li, Xiaogang Wang, Bin Liu, and Nenghai Yu. Online multi-object tracking using cnn-based single object tracker with spatial-temporal attention mechanism. In ICCV, 2017. 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 53, + 586, + 287, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 586, + 287, + 624 + ], + "spans": [ + { + "bbox": [ + 53, + 586, + 287, + 624 + ], + "type": "text", + "content": "[17] Marius Cordts, Mohamed Omran, Sebastian Ramos, Timo Rehfeld, Markus Enzweiler, Rodrigo Benenson, Uwe Franke, Stefan Roth, and Bernt Schiele. The cityscapes dataset for semantic urban scene understanding. In CVPR, 2016. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 53, + 625, + 287, + 654 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 625, + 287, + 654 + ], + "spans": [ + { + "bbox": [ + 53, + 625, + 287, + 654 + ], + "type": "text", + "content": "[18] Henghui Ding, Xudong Jiang, Bing Shuai, Ai Qun Liu, and Gang Wang. Semantic segmentation with context encoding and multi-path decoding. IEEE TIP, 29, 2020. 3" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 53, + 655, + 287, + 684 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 655, + 287, + 684 + ], + "spans": [ + { + "bbox": [ + 53, + 655, + 287, + 684 + ], + "type": "text", + "content": "[19] Henghui Ding, Chang Liu, Shuting He, Xudong Jiang, and Chen Change Loy. MeViS: A large-scale benchmark for video segmentation with motion expressions. In ICCV, 2023. 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 53, + 685, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 685, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 53, + 685, + 287, + 712 + ], + "type": "text", + "content": "[20] Henghui Ding, Chang Liu, Suchen Wang, and Xudong Jiang. VLT: Vision-language transformer and query generation for referring segmentation. IEEE TPAMI, 2023. 3" + } + ] + } + ], + "index": 20 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 312, + 74, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 45, + "blocks": [ + { + "bbox": [ + 312, + 74, + 545, + 102 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 74, + 545, + 102 + ], + "spans": [ + { + "bbox": [ + 312, + 74, + 545, + 102 + ], + "type": "text", + "content": "[21] Kevin Duarte, Yogesh S. Rawat, and Mubarak Shah. Capsulevos: Semi-supervised video object segmentation using capsule routing. In ICCV, 2019. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 312, + 102, + 545, + 131 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 102, + 545, + 131 + ], + "spans": [ + { + "bbox": [ + 312, + 102, + 545, + 131 + ], + "type": "text", + "content": "[22] Brendan Duke, Abdalla Ahmed, Christian Wolf, Parham Aarabi, and Graham W Taylor. Sstvos: Sparse spatiotemporal transformers for video object segmentation. In CVPR, 2021. 2" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 312, + 133, + 545, + 169 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 133, + 545, + 169 + ], + "spans": [ + { + "bbox": [ + 312, + 133, + 545, + 169 + ], + "type": "text", + "content": "[23] Qingnan Fan, Fan Zhong, Dani Lischinski, Daniel Cohen-Or, and Baoquan Chen. JumpCut: non-successive mask transfer and interpolation for video cutout. ACM Tran. Graphics, 34(6), 2015. 5" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 312, + 171, + 545, + 198 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 171, + 545, + 198 + ], + "spans": [ + { + "bbox": [ + 312, + 171, + 545, + 198 + ], + "type": "text", + "content": "[24] Katerina Fragkiadaki, Pablo Arbelaez, Panna Felsen, and Jitendra Malik. Learning to segment moving objects in videos. In CVPR, 2015. 3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 312, + 199, + 545, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 199, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 312, + 199, + 545, + 228 + ], + "type": "text", + "content": "[25] Junwei Han, Le Yang, Dingwen Zhang, Xiaojun Chang, and Xiaodan Liang. Reinforcement cutting-agent learning for video object segmentation. In CVPR, 2018. 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 312, + 229, + 545, + 248 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 229, + 545, + 248 + ], + "spans": [ + { + "bbox": [ + 312, + 229, + 545, + 248 + ], + "type": "text", + "content": "[26] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, 2016. 6" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 312, + 249, + 545, + 277 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 249, + 545, + 277 + ], + "spans": [ + { + "bbox": [ + 312, + 249, + 545, + 277 + ], + "type": "text", + "content": "[27] Yuk Heo, Yeong Jun Koh, and Chang-Su Kim. Interactive video object segmentation using global and local transfer modules. In ECCV, 2020. 7" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 312, + 277, + 545, + 305 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 277, + 545, + 305 + ], + "spans": [ + { + "bbox": [ + 312, + 277, + 545, + 305 + ], + "type": "text", + "content": "[28] Yuk Heo, Yeong Jun Koh, and Chang-Su Kim. Guided interactive video object segmentation using reliability-based attention maps. In CVPR, 2021. 3, 7" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 312, + 307, + 545, + 335 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 307, + 545, + 335 + ], + "spans": [ + { + "bbox": [ + 312, + 307, + 545, + 335 + ], + "type": "text", + "content": "[29] Li Hu, Peng Zhang, Bang Zhang, Pan Pan, Yinghui Xu, and Rong Jin. Learning position and target consistency for memory-based video object segmentation. In CVPR, 2021. 2" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 312, + 335, + 545, + 364 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 335, + 545, + 364 + ], + "spans": [ + { + "bbox": [ + 312, + 335, + 545, + 364 + ], + "type": "text", + "content": "[30] Ping Hu, Gang Wang, Xiangfei Kong, Jason Kuen, and Yap-Peng Tan. Motion-guided cascaded refinement network for video object segmentation. In CVPR, 2018. 2" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 312, + 365, + 545, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 365, + 545, + 392 + ], + "spans": [ + { + "bbox": [ + 312, + 365, + 545, + 392 + ], + "type": "text", + "content": "[31] Xuhua Huang, Jiarui Xu, Yu-Wing Tai, and Chi-Keung Tang. Fast video object segmentation with temporal aggregation network and dynamic template matching. In CVPR, 2020. 2" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 312, + 393, + 545, + 422 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 393, + 545, + 422 + ], + "spans": [ + { + "bbox": [ + 312, + 393, + 545, + 422 + ], + "type": "text", + "content": "[32] Allan Jabri, Andrew Owens, and Alexei Efros. Space-time correspondence as a contrastive random walk. In NeurIPS, 2020. 2" + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 312, + 422, + 545, + 451 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 422, + 545, + 451 + ], + "spans": [ + { + "bbox": [ + 312, + 422, + 545, + 451 + ], + "type": "text", + "content": "[33] Suyog Dutt Jain, Bo Xiong, and Kristen Grauman. Fusionseg: Learning to combine motion and appearance for fully automatic segmentation of generic objects in videos. In CVPR, 2017. 1, 3" + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 312, + 452, + 545, + 471 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 452, + 545, + 471 + ], + "spans": [ + { + "bbox": [ + 312, + 452, + 545, + 471 + ], + "type": "text", + "content": "[34] Varun Jampani, Raghudeep Gadde, and Peter V. Gehler. Video propagation networks. In CVPR, 2017. 2" + } + ] + } + ], + "index": 35 + }, + { + "bbox": [ + 312, + 472, + 545, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 472, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 312, + 472, + 545, + 498 + ], + "type": "text", + "content": "[35] Won-Dong Jang and Chang-Su Kim. Online video object segmentation via convolutional trident network. In CVPR, 2017. 2" + } + ] + } + ], + "index": 36 + }, + { + "bbox": [ + 312, + 500, + 545, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 500, + 545, + 529 + ], + "spans": [ + { + "bbox": [ + 312, + 500, + 545, + 529 + ], + "type": "text", + "content": "[36] Lei Ke, Henghui Ding, Martin Danelljan, Yu-Wing Tai, Chi-Keung Tang, and Fisher Yu. Video mask transfiner for high-quality video instance segmentation. In ECCV. Springer, 2022. 3" + } + ] + } + ], + "index": 37 + }, + { + "bbox": [ + 312, + 529, + 545, + 548 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 529, + 545, + 548 + ], + "spans": [ + { + "bbox": [ + 312, + 529, + 545, + 548 + ], + "type": "text", + "content": "[37] Lei Ke, Yu-Wing Tai, and Chi-Keung Tang. Deep occlusion-aware instance segmentation with overlapping bilayers. In CVPR, 2021. 3" + } + ] + } + ], + "index": 38 + }, + { + "bbox": [ + 312, + 549, + 545, + 568 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 549, + 545, + 568 + ], + "spans": [ + { + "bbox": [ + 312, + 549, + 545, + 568 + ], + "type": "text", + "content": "[38] Dahun Kim, Sanghyun Woo, Joon-Young Lee, and In So Kweon. Video panoptic segmentation. In CVPR, 2020. 3" + } + ] + } + ], + "index": 39 + }, + { + "bbox": [ + 312, + 569, + 545, + 606 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 569, + 545, + 606 + ], + "spans": [ + { + "bbox": [ + 312, + 569, + 545, + 606 + ], + "type": "text", + "content": "[39] Adam Kortylewski, Qing Liu, Angtian Wang, Yihong Sun, and Alan Yuille. Compositional convolutional neural networks: A robust and interpretable model for object recognition under occlusion. IJCV, 129(3), 2021. 3" + } + ] + } + ], + "index": 40 + }, + { + "bbox": [ + 312, + 607, + 545, + 625 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 607, + 545, + 625 + ], + "spans": [ + { + "bbox": [ + 312, + 607, + 545, + 625 + ], + "type": "text", + "content": "[40] Zihang Lai, Erika Lu, and Weidi Xie. MAST: A memory-augmented self-supervised tracker. In CVPR, 2020. 2" + } + ] + } + ], + "index": 41 + }, + { + "bbox": [ + 312, + 626, + 545, + 654 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 626, + 545, + 654 + ], + "spans": [ + { + "bbox": [ + 312, + 626, + 545, + 654 + ], + "type": "text", + "content": "[41] Justin Lazarow, Kwonjoon Lee, Kunyu Shi, and Zhuowen Tu. Learning instance occlusion for panoptic segmentation. In CVPR, 2020. 3" + } + ] + } + ], + "index": 42 + }, + { + "bbox": [ + 312, + 655, + 545, + 684 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 655, + 545, + 684 + ], + "spans": [ + { + "bbox": [ + 312, + 655, + 545, + 684 + ], + "type": "text", + "content": "[42] Fuxin Li, Taeyoung Kim, Ahmad Humayun, David Tsai, and James M Rehg. Video segmentation by tracking many figure-ground segments. In ICCV, 2013. 5" + } + ] + } + ], + "index": 43 + }, + { + "bbox": [ + 312, + 685, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 685, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 312, + 685, + 545, + 712 + ], + "type": "text", + "content": "[43] Guanbin Li, Yuan Xie, Tianhao Wei, Keze Wang, and Liang Lin. Flow guided recurrent neural encoder for video salient object detection. In CVPR, 2018. 3" + } + ] + } + ], + "index": 44 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "20232" + } + ] + } + ], + "index": 46 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 52, + 74, + 286, + 712 + ], + "type": "list", + "angle": 0, + "index": 21, + "blocks": [ + { + "bbox": [ + 52, + 74, + 286, + 101 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 74, + 286, + 101 + ], + "spans": [ + { + "bbox": [ + 52, + 74, + 286, + 101 + ], + "type": "text", + "content": "[44] Haofeng Li, Guanqi Chen, Guanbin Li, and Yizhou Yu. Motion guided attention for video salient object detection. In ICCV, 2019. 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 53, + 103, + 286, + 131 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 103, + 286, + 131 + ], + "spans": [ + { + "bbox": [ + 53, + 103, + 286, + 131 + ], + "type": "text", + "content": "[45] Mingxing Li, Li Hu, Zhiwei Xiong, Bang Zhang, Pan Pan, and Dong Liu. Recurrent dynamic embedding for video object segmentation. In CVPR, 2022. 6, 7" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 133, + 286, + 159 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 133, + 286, + 159 + ], + "spans": [ + { + "bbox": [ + 53, + 133, + 286, + 159 + ], + "type": "text", + "content": "[46] Siyuan Li, Martin Danelljan, Henghui Ding, Thomas E Huang, and Fisher Yu. Tracking every thing in the wild. In ECCV. Springer, 2022. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 161, + 286, + 198 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 161, + 286, + 198 + ], + "spans": [ + { + "bbox": [ + 53, + 161, + 286, + 198 + ], + "type": "text", + "content": "[47] Xiangtai Li, Henghui Ding, Wenwei Zhang, Haobo Yuan, Jiangmiao Pang, Guangliang Cheng, Kai Chen, Ziwei Liu, and Chen Change Loy. Transformer-based visual segmentation: A survey. arXiv preprint arXiv:2304.09854, 2023. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 200, + 286, + 237 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 200, + 286, + 237 + ], + "spans": [ + { + "bbox": [ + 53, + 200, + 286, + 237 + ], + "type": "text", + "content": "[48] Xiangtai Li, Hao He, Yibo Yang, Henghui Ding, Kuiyuan Yang, Guangliang Cheng, Yunhai Tong, and Dacheng Tao. Improving video instance segmentation via temporal pyramid routing. IEEE TPAMI, 2022. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 239, + 286, + 276 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 239, + 286, + 276 + ], + "spans": [ + { + "bbox": [ + 53, + 239, + 286, + 276 + ], + "type": "text", + "content": "[49] Chen Liang, Yu Wu, Tianfei Zhou, Wenguan Wang, Zongxin Yang, Yunchao Wei, and Yi Yang. Rethinking cross-modal interaction from a top-down perspective for referring video object segmentation. arXiv preprint arXiv:2106.01061, 2021. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 277, + 286, + 305 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 277, + 286, + 305 + ], + "spans": [ + { + "bbox": [ + 53, + 277, + 286, + 305 + ], + "type": "text", + "content": "[50] Fanchao Lin, Hongtao Xie, Yan Li, and Yongdong Zhang. Query-memory re-aggregation for weakly-supervised video object segmentation. In AAAI, 2021. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 306, + 286, + 325 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 306, + 286, + 325 + ], + "spans": [ + { + "bbox": [ + 53, + 306, + 286, + 325 + ], + "type": "text", + "content": "[51] Huaijia Lin, Xiaojuan Qi, and Jiaya Jia. Agss-vos: Attention guided single-shot video object segmentation. In CVPR, 2019. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 326, + 286, + 354 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 326, + 286, + 354 + ], + "spans": [ + { + "bbox": [ + 53, + 326, + 286, + 354 + ], + "type": "text", + "content": "[52] Tsung-Yi Lin, Michael Maire, Serge J Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In ECCV, 2014. 4" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 355, + 286, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 355, + 286, + 392 + ], + "spans": [ + { + "bbox": [ + 53, + 355, + 286, + 392 + ], + "type": "text", + "content": "[53] Zhihui Lin, Tianyu Yang, Maomao Li, Ziyu Wang, Chun Yuan, Wenhao Jiang, and Wei Liu. Swem: Towards real-time video object segmentation with sequential weighted expectation-maximization. In CVPR, 2022. 6, 7" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 393, + 286, + 422 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 393, + 286, + 422 + ], + "spans": [ + { + "bbox": [ + 53, + 393, + 286, + 422 + ], + "type": "text", + "content": "[54] Daizong Liu, Dongdong Yu, Changhu Wang, and Pan Zhou. F2net: Learning to focus on the foreground for unsupervised video object segmentation. In AAAI, 2021. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 53, + 423, + 286, + 441 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 423, + 286, + 441 + ], + "spans": [ + { + "bbox": [ + 53, + 423, + 286, + 441 + ], + "type": "text", + "content": "[55] Qiankun Liu, Qi Chu, Bin Liu, and Nenghai Yu. Gsm: Graph similarity model for multi-object tracking. In IJCAI, 2020. 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 53, + 442, + 286, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 442, + 286, + 470 + ], + "spans": [ + { + "bbox": [ + 53, + 442, + 286, + 470 + ], + "type": "text", + "content": "[56] Si Liu, Tianrui Hui, Shaofei Huang, Yunchao Wei, Bo Li, and Guanbin Li. Cross-modal progressive comprehension for referring segmentation. IEEE TPAMI, 2021. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 53, + 472, + 286, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 472, + 286, + 498 + ], + "spans": [ + { + "bbox": [ + 53, + 472, + 286, + 498 + ], + "type": "text", + "content": "[57] Jonathan Long, Evan Shelhamer, and Trevor Darrell. Fully convolutional networks for semantic segmentation. In CVPR, 2015. 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 53, + 500, + 286, + 528 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 500, + 286, + 528 + ], + "spans": [ + { + "bbox": [ + 53, + 500, + 286, + 528 + ], + "type": "text", + "content": "[58] Xinkai Lu, Wenguan Wang, Martin Danelljan, Tianfei Zhou, Jianbing Shen, and Luc Van Gool. Video object segmentation with episodic graph memory networks. In ECCV, 2020. 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 53, + 529, + 286, + 567 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 529, + 286, + 567 + ], + "spans": [ + { + "bbox": [ + 53, + 529, + 286, + 567 + ], + "type": "text", + "content": "[59] Xiankai Lu, Wenguan Wang, Chao Ma, Jianbing Shen, Ling Shao, and Fatih Porikli. See more, know more: Unsupervised video object segmentation with co-attention siamese networks. In CVPR, 2019. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 53, + 568, + 286, + 595 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 568, + 286, + 595 + ], + "spans": [ + { + "bbox": [ + 53, + 568, + 286, + 595 + ], + "type": "text", + "content": "[60] Xiankai Lu, Wenguan Wang, Jianbing Shen, David Crandall, and Luc Van Gool. Segmenting objects from relational visual data. IEEE TPAMI, 2021. 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 53, + 597, + 286, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 597, + 286, + 624 + ], + "spans": [ + { + "bbox": [ + 53, + 597, + 286, + 624 + ], + "type": "text", + "content": "[61] Xiankai Lu, Wenguan Wang, Jianbing Shen, Yu-Wing Tai, David J Crandall, and Steven CH Hoi. Learning video object segmentation from unlabeled videos. In CVPR, 2020. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 53, + 626, + 286, + 654 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 626, + 286, + 654 + ], + "spans": [ + { + "bbox": [ + 53, + 626, + 286, + 654 + ], + "type": "text", + "content": "[62] David R Martin, Charless C Fowlkes, and Jitendra Malik. Learning to detect natural image boundaries using local brightness, color, and texture cues. IEEE TPAMI, 26(5), 2004. 6" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 53, + 655, + 286, + 683 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 655, + 286, + 683 + ], + "spans": [ + { + "bbox": [ + 53, + 655, + 286, + 683 + ], + "type": "text", + "content": "[63] Bo Miao, Mohammed Bennamoun, Yongsheng Gao, and Ajmal Mian. Region aware video object segmentation with deep motion modeling. arXiv preprint arXiv:2207.10258, 2022. 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 53, + 685, + 286, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 685, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 53, + 685, + 286, + 712 + ], + "type": "text", + "content": "[64] Jiaxu Miao, Xiaohan Wang, Yu Wu, Wei Li, Xu Zhang, Yunchao Wei, and Yi Yang. Large-scale video panoptic segmentation in the wild: A benchmark. In CVPR, 2022. 3" + } + ] + } + ], + "index": 20 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 312, + 74, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 43, + "blocks": [ + { + "bbox": [ + 312, + 74, + 545, + 102 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 74, + 545, + 102 + ], + "spans": [ + { + "bbox": [ + 312, + 74, + 545, + 102 + ], + "type": "text", + "content": "[65] Jiaxu Miao, Yunchao Wei, Yu Wu, Chen Liang, Guangrui Li, and Yi Yang. Vspw: A large-scale dataset for video scene parsing in the wild. In CVPR, 2021. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 312, + 104, + 545, + 131 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 104, + 545, + 131 + ], + "spans": [ + { + "bbox": [ + 312, + 104, + 545, + 131 + ], + "type": "text", + "content": "[66] Jiaxu Miao, Yunchao Wei, and Yi Yang. Memory aggregation networks for efficient interactive video object segmentation. In CVPR, 2020. 3, 7" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 312, + 133, + 545, + 160 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 133, + 545, + 160 + ], + "spans": [ + { + "bbox": [ + 312, + 133, + 545, + 160 + ], + "type": "text", + "content": "[67] Peter Ochs, Jitendra Malik, and Thomas Brox. Segmentation of moving objects by long term video analysis. IEEE TPAMI, 36(6), 2014. 5" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 312, + 163, + 545, + 191 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 163, + 545, + 191 + ], + "spans": [ + { + "bbox": [ + 312, + 163, + 545, + 191 + ], + "type": "text", + "content": "[68] Seoung Wug Oh, Joon-Young Lee, Ning Xu, and Seon Joo Kim. Fast user-guided video object segmentation by interaction-and-propagation networks. In CVPR, 2019. 2, 3, 7" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 312, + 193, + 545, + 220 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 193, + 545, + 220 + ], + "spans": [ + { + "bbox": [ + 312, + 193, + 545, + 220 + ], + "type": "text", + "content": "[69] Seoung Wug Oh, Joon-Young Lee, Ning Xu, and Seon Joo Kim. Video object segmentation using space-time memory networks. In ICCV, 2019. 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 312, + 222, + 545, + 250 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 222, + 545, + 250 + ], + "spans": [ + { + "bbox": [ + 312, + 222, + 545, + 250 + ], + "type": "text", + "content": "[70] Seoung Wug Oh, Joon Young Lee, Ning Xu, and Seon Joo Kim. Video object segmentation using space-time memory networks. In ICCV, 2019. 7" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 312, + 251, + 545, + 279 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 251, + 545, + 279 + ], + "spans": [ + { + "bbox": [ + 312, + 251, + 545, + 279 + ], + "type": "text", + "content": "[71] Hyojin Park, Jayeon Yoo, Seohyeong Jeong, Ganesh Venkatesh, and Nojun Kwak. Learning dynamic network using a reuse gate function in semi-supervised video object segmentation. In CVPR, 2021. 1" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 312, + 281, + 545, + 309 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 281, + 545, + 309 + ], + "spans": [ + { + "bbox": [ + 312, + 281, + 545, + 309 + ], + "type": "text", + "content": "[72] Federico Peruzzi, Anna Khoreva, Rodrigo Benenson, Bernt Schiele, and Alexander Sorkine-Hornung. Learning video object segmentation from static images. In CVPR, 2017. 2" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 312, + 311, + 545, + 348 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 311, + 545, + 348 + ], + "spans": [ + { + "bbox": [ + 312, + 311, + 545, + 348 + ], + "type": "text", + "content": "[73] Federico Perazzi, Jordi Pont-Tuset, Brian McWilliams, Luc Van Gool, Markus Gross, and Alexander Sorkine-Hornung. A benchmark dataset and evaluation methodology for video object segmentation. In CVPR, 2016. 1, 2, 5, 6" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 312, + 350, + 545, + 387 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 350, + 545, + 387 + ], + "spans": [ + { + "bbox": [ + 312, + 350, + 545, + 387 + ], + "type": "text", + "content": "[74] Jordi Pont-Tuset, Federico Perazzi, Sergi Caelles, Pablo Arbeláez, Alex Sorkine-Hornung, and Luc Van Gool. The 2017 davis challenge on video object segmentation. arXiv preprint arXiv:1704.00675, 2017. 1, 2, 5, 6, 7" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 312, + 388, + 545, + 417 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 388, + 545, + 417 + ], + "spans": [ + { + "bbox": [ + 312, + 388, + 545, + 417 + ], + "type": "text", + "content": "[75] Alessandro Prest, Christian Leistner, Javier Civera, Cordelia Schmid, and Vittorio Ferrari. Learning object class detectors from weakly annotated video. In CVPR, 2012. 5" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 312, + 418, + 545, + 455 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 418, + 545, + 455 + ], + "spans": [ + { + "bbox": [ + 312, + 418, + 545, + 455 + ], + "type": "text", + "content": "[76] Jiyang Qi, Yan Gao, Yao Hu, Xinggang Wang, Xiaoyu Liu, Xiang Bai, Serge Belongie, Alan Yuille, Philip HS Torr, and Song Bai. Occluded video instance segmentation: A benchmark. IJCV, 130(8), 2022. 3, 4, 5" + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 312, + 457, + 545, + 485 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 457, + 545, + 485 + ], + "spans": [ + { + "bbox": [ + 312, + 457, + 545, + 485 + ], + "type": "text", + "content": "[77] Siyuan Qiao, Yukun Zhu, Hartwig Adam, Alan Yuille, and Liang-Chieh Chen. Vip-deeplab: Learning visual perception with depth-aware video panoptic segmentation. In CVPR, 2021. 3" + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 312, + 487, + 545, + 515 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 487, + 545, + 515 + ], + "spans": [ + { + "bbox": [ + 312, + 487, + 545, + 515 + ], + "type": "text", + "content": "[78] Sucheng Ren, Wenxi Liu, Yongtuo Liu, Haoxin Chen, Guoqiang Han, and Shengfeng He. Reciprocal transformations for unsupervised video object segmentation. In CVPR, 2021. 3" + } + ] + } + ], + "index": 35 + }, + { + "bbox": [ + 312, + 517, + 545, + 544 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 517, + 545, + 544 + ], + "spans": [ + { + "bbox": [ + 312, + 517, + 545, + 544 + ], + "type": "text", + "content": "[79] Seonguk Seo, Joon-Young Lee, and Bohyung Han. Urvos: Unified referring video object segmentation network with a large-scale benchmark. In ECCV, 2020. 3" + } + ] + } + ], + "index": 36 + }, + { + "bbox": [ + 312, + 546, + 545, + 574 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 546, + 545, + 574 + ], + "spans": [ + { + "bbox": [ + 312, + 546, + 545, + 574 + ], + "type": "text", + "content": "[80] Guolei Sun, Yun Liu, Henghui Ding, Thomas Probst, and Luc Van Gool. Coarse-to-fine feature mining for video semantic segmentation. In CVPR, 2022. 3" + } + ] + } + ], + "index": 37 + }, + { + "bbox": [ + 312, + 576, + 545, + 603 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 576, + 545, + 603 + ], + "spans": [ + { + "bbox": [ + 312, + 576, + 545, + 603 + ], + "type": "text", + "content": "[81] Mingjie Sun, Jimin Xiao, Eng Gee Lim, Bingfeng Zhang, and Yao Zhao. Fast template matching and update for video object tracking and segmentation. In CVPR, 2020. 3, 7" + } + ] + } + ], + "index": 38 + }, + { + "bbox": [ + 312, + 605, + 545, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 605, + 545, + 624 + ], + "spans": [ + { + "bbox": [ + 312, + 605, + 545, + 624 + ], + "type": "text", + "content": "[82] Pavel Tokmakov, Karteek Alahari, and Cordelia Schmid. Learning video object segmentation with visual memory. In ICCV, 2017. 3" + } + ] + } + ], + "index": 39 + }, + { + "bbox": [ + 312, + 625, + 545, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 625, + 545, + 644 + ], + "spans": [ + { + "bbox": [ + 312, + 625, + 545, + 644 + ], + "type": "text", + "content": "[83] Pavel Tokmakov, Cordelia Schmid, and Karteek Alahari. Learning to segment moving objects. IJCV, 127(3), 2019. 3" + } + ] + } + ], + "index": 40 + }, + { + "bbox": [ + 312, + 646, + 545, + 673 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 646, + 545, + 673 + ], + "spans": [ + { + "bbox": [ + 312, + 646, + 545, + 673 + ], + "type": "text", + "content": "[84] Carles Ventura, Miriam Bellver, Andreu Girbau, Amaia Salvador, Ferran Marques, and Xavier Giro-i Nieto. Rvos: End-to-end recurrent network for video object segmentation. In CVPR, 2019. 7" + } + ] + } + ], + "index": 41 + }, + { + "bbox": [ + 312, + 675, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 675, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 312, + 675, + 545, + 712 + ], + "type": "text", + "content": "[85] Paul Voigtlaender, Yuning Chai, Florian Schroff, Hartwig Adam, Bastian Leibe, and Liang-Chieh Chen. Feelvos: Fast end-to-end embedding learning for video object segmentation. In CVPR, 2019." + } + ] + } + ], + "index": 42 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "text", + "content": "20233" + } + ] + } + ], + "index": 44 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 74, + 288, + 499 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 52, + 74, + 287, + 102 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 74, + 287, + 102 + ], + "spans": [ + { + "bbox": [ + 52, + 74, + 287, + 102 + ], + "type": "text", + "content": "[86] Qiang Wang, Li Zhang, Luca Bertinetto, Weiming Hu, and Philip HS Torr. Fast online object tracking and segmentation: A unifying approach. In CVPR, 2019. 3, 7" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 52, + 102, + 288, + 129 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 102, + 288, + 129 + ], + "spans": [ + { + "bbox": [ + 52, + 102, + 288, + 129 + ], + "type": "text", + "content": "[87] Wenguan Wang, Xiankai Lu, Jianbing Shen, David J Crandall, and Ling Shao. Zero-shot video object segmentation via attentive graph neural networks. In ICCV, 2019. 3, 7" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 52, + 130, + 287, + 167 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 130, + 287, + 167 + ], + "spans": [ + { + "bbox": [ + 52, + 130, + 287, + 167 + ], + "type": "text", + "content": "[88] Wenguan Wang, Hongmei Song, Shuyang Zhao, Jianbing Shen, Sanyuan Zhao, Steven CH Ho, and Haibin Ling. Learning unsupervised video object segmentation through visual attention. In CVPR, 2019. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 52, + 168, + 288, + 197 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 168, + 288, + 197 + ], + "spans": [ + { + "bbox": [ + 52, + 168, + 288, + 197 + ], + "type": "text", + "content": "[89] Wenguan Wang, Tianfei Zhou, Fatih Porikli, David Crandall, and Luc Van Gool. A survey on deep learning technique for video segmentation. arXiv preprint arXiv:2107.01153, 2021. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 52, + 198, + 288, + 224 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 198, + 288, + 224 + ], + "spans": [ + { + "bbox": [ + 52, + 198, + 288, + 224 + ], + "type": "text", + "content": "[90] Xinlong Wang, Tete Xiao, Yuning Jiang, Shuai Shao, Jian Sun, and Chunhua Shen. Repulsion loss: Detecting pedestrians in a crowd. In CVPR, 2018. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 52, + 225, + 288, + 253 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 225, + 288, + 253 + ], + "spans": [ + { + "bbox": [ + 52, + 225, + 288, + 253 + ], + "type": "text", + "content": "[91] Ziqin Wang, Jun Xu, Li Liu, Fan Zhu, and Ling Shao. Ranet: Ranking attention network for fast video object segmentation. In ICCV, 2019. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 52, + 254, + 288, + 281 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 254, + 288, + 281 + ], + "spans": [ + { + "bbox": [ + 52, + 254, + 288, + 281 + ], + "type": "text", + "content": "[92] Sanghyun Woo, Dahun Kim, Joon-Young Lee, and In So Kweon. Learning to associate every segment for video panoptic segmentation. In CVPR, 2021. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 52, + 282, + 288, + 311 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 282, + 288, + 311 + ], + "spans": [ + { + "bbox": [ + 52, + 282, + 288, + 311 + ], + "type": "text", + "content": "[93] Dongming Wu, Xingping Dong, Ling Shao, and Jianbing Shen. Multi-level representation learning with semantic alignment for referring video object segmentation. In CVPR, 2022. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 52, + 312, + 288, + 339 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 312, + 288, + 339 + ], + "spans": [ + { + "bbox": [ + 52, + 312, + 288, + 339 + ], + "type": "text", + "content": "[94] Seoung Wug Oh, Joon-Young Lee, Kalyan Sunkavalli, and Seon Joo Kim. Fast video object segmentation by reference-guided mask propagation. In CVPR, 2018. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 52, + 339, + 288, + 367 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 339, + 288, + 367 + ], + "spans": [ + { + "bbox": [ + 52, + 339, + 288, + 367 + ], + "type": "text", + "content": "[95] Huaxin Xiao, Jiashi Feng, Guosheng Lin, Yu Liu, and Maojun Zhang. Monet: Deep motion exploitation for video object segmentation. In CVPR, 2018. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 52, + 368, + 288, + 386 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 368, + 288, + 386 + ], + "spans": [ + { + "bbox": [ + 52, + 368, + 288, + 386 + ], + "type": "text", + "content": "[96] Jiarui Xu, Yue Cao, Zheng Zhang, and Han Hu. Spatial-temporal relation networks for multi-object tracking. In ICCV, 2019. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 52, + 387, + 288, + 423 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 387, + 288, + 423 + ], + "spans": [ + { + "bbox": [ + 52, + 387, + 288, + 423 + ], + "type": "text", + "content": "[97] Ning Xu, Linjie Yang, Yuchen Fan, Jianchao Yang, Dingcheng Yue, Yuchen Liang, Brian Price, Scott Cohen, and Thomas Huang. Youtube-vos: Sequence-to-sequence video object segmentation. In ECCV, 2018. 1, 2, 5, 6, 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 52, + 424, + 288, + 452 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 424, + 288, + 452 + ], + "spans": [ + { + "bbox": [ + 52, + 424, + 288, + 452 + ], + "type": "text", + "content": "[98] Shuangjie Xu, Daizong Liu, Linchao Bao, Wei Liu, and Pan Zhou. Mhp-vos: Multiple hypotheses propagation for video object segmentation. In CVPR, 2019. 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 52, + 453, + 288, + 472 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 453, + 288, + 472 + ], + "spans": [ + { + "bbox": [ + 52, + 453, + 288, + 472 + ], + "type": "text", + "content": "[99] Linjie Yang, Yuchen Fan, and Ning Xu. Video instance segmentation. In ICCV, 2019. 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 472, + 287, + 499 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 472, + 287, + 499 + ], + "spans": [ + { + "bbox": [ + 48, + 472, + 287, + 499 + ], + "type": "text", + "content": "[100] Yanchao Yang, Brian Lai, and Stefano Soatto. Dystab: Unsupervised object segmentation via dynamic-static bootstrapping. In CVPR, 2021. 3" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 74, + 545, + 499 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 307, + 74, + 545, + 102 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 74, + 545, + 102 + ], + "spans": [ + { + "bbox": [ + 307, + 74, + 545, + 102 + ], + "type": "text", + "content": "[101] Zhao Yang, Qiang Wang, Luca Bertinetto, Weiming Hu, Song Bai, and Philip HS Torr. Anchor diffusion for unsupervised video object segmentation. In ICCV, 2019. 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 104, + 545, + 133 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 104, + 545, + 133 + ], + "spans": [ + { + "bbox": [ + 307, + 104, + 545, + 133 + ], + "type": "text", + "content": "[102] Zongxin Yang, Yunchao Wei, and Yi Yang. Collaborative video object segmentation by foreground-background integration. In ECCV, 2020. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 135, + 545, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 135, + 545, + 173 + ], + "spans": [ + { + "bbox": [ + 307, + 135, + 545, + 173 + ], + "type": "text", + "content": "[103] Zongxin Yang, Yunchao Wei, and Yi Yang. Associating objects with transformers for video object segmentation. In M. Ranzato, A. Beygelzimer, Y. Dauphin, P.S. Liang, and J. Wortman Vaughan, editors, NeurIPS, volume 34. Curran Associates, Inc., 2021. 6, 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 175, + 545, + 203 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 175, + 545, + 203 + ], + "spans": [ + { + "bbox": [ + 307, + 175, + 545, + 203 + ], + "type": "text", + "content": "[104] Zongxin Yang and Yi Yang. Decoupling features in hierarchical propagation for video object segmentation. In NeurIPS, 2022. 2, 6, 7" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 206, + 545, + 235 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 206, + 545, + 235 + ], + "spans": [ + { + "bbox": [ + 307, + 206, + 545, + 235 + ], + "type": "text", + "content": "[105] Linwei Ye, Mrigank Rochan, Zhi Liu, Xiaoqin Zhang, and Yang Wang. Referring segmentation in images and videos with cross-modal self-attention network. IEEE TPAMI, 2021. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 237, + 545, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 237, + 545, + 274 + ], + "spans": [ + { + "bbox": [ + 307, + 237, + 545, + 274 + ], + "type": "text", + "content": "[106] Zhaoyuan Yin, Jia Zheng, Weixin Luo, Shenhan Qian, Hanling Zhang, and Shenghua Gao. Learning to recommend frame for interactive video object segmentation in the wild. In CVPR, 2021. 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 276, + 545, + 313 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 276, + 545, + 313 + ], + "spans": [ + { + "bbox": [ + 307, + 276, + 545, + 313 + ], + "type": "text", + "content": "[107] Jae Shin Yoon, François Rameau, Jun-Sik Kim, Seokju Lee, Seunghak Shin, and In So Kweon. Pixel-level matching for video object segmentation using convolutional neural networks. In ICCV, 2017. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 316, + 545, + 344 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 316, + 545, + 344 + ], + "spans": [ + { + "bbox": [ + 307, + 316, + 545, + 344 + ], + "type": "text", + "content": "[108] Xiaohang Zhan, Xingang Pan, Bo Dai, Ziwei Liu, Dahua Lin, and Chen Change Loy. Self-supervised scene de-occlusion. In CVPR, 2020. 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 347, + 545, + 375 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 347, + 545, + 375 + ], + "spans": [ + { + "bbox": [ + 307, + 347, + 545, + 375 + ], + "type": "text", + "content": "[109] Lu Zhang, Zhe Lin, Jianming Zhang, Huchuan Lu, and You He. Fast video object segmentation via dynamic targeting network. In ICCV, 2019. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 378, + 545, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 378, + 545, + 407 + ], + "spans": [ + { + "bbox": [ + 307, + 378, + 545, + 407 + ], + "type": "text", + "content": "[110] Shifeng Zhang, Longyin Wen, Xiao Bian, Zhen Lei, and Stan Z Li. Occlusion-aware r-cnn: Detecting pedestrians in a crowd. In ECCV, 2018.3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 409, + 545, + 437 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 409, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 307, + 409, + 545, + 437 + ], + "type": "text", + "content": "[111] Yizhuo Zhang, Zhirong Wu, Houwen Peng, and Stephen Lin. A transductive approach for video object segmentation. In CVPR, 2020. 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 440, + 545, + 468 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 440, + 545, + 468 + ], + "spans": [ + { + "bbox": [ + 307, + 440, + 545, + 468 + ], + "type": "text", + "content": "[112] Tianfei Zhou, Shunzhou Wang, Yi Zhou, Yazhou Yao, Jianwu Li, and Ling Shao. Motion-attentive transition for zero-shot video object segmentation. In AAAI, 2020. 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 471, + 545, + 499 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 471, + 545, + 499 + ], + "spans": [ + { + "bbox": [ + 307, + 471, + 545, + 499 + ], + "type": "text", + "content": "[113] Ji Zhu, Hua Yang, Nian Liu, Minyoung Kim, Wenjun Zhang, and Ming-Hsuan Yang. Online multi-object tracking with dual matching attention networks. In ECCV, 2018. 3" + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "text", + "content": "20234" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/b6bef65d-9eb6-4535-9de8-7c08bf88dd4b_content_list.json b/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/b6bef65d-9eb6-4535-9de8-7c08bf88dd4b_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..b09ac0929ee4ddf6231c749adf88928fcea39851 --- /dev/null +++ b/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/b6bef65d-9eb6-4535-9de8-7c08bf88dd4b_content_list.json @@ -0,0 +1,1857 @@ +[ + { + "type": "text", + "text": "MOST: Multiple Object localization with Self-supervised Transformers for object discovery", + "text_level": 1, + "bbox": [ + 109, + 128, + 861, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Sai Saketh Rambhatla1,3*", + "bbox": [ + 99, + 202, + 302, + 220 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "rssaketh@meta.com", + "bbox": [ + 122, + 224, + 276, + 236 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Ishan Misra", + "bbox": [ + 349, + 203, + 450, + 220 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "imisra@meta.com", + "bbox": [ + 334, + 224, + 468, + 237 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Rama Chellappa2,3", + "bbox": [ + 506, + 203, + 656, + 220 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "rchella4@jhu.edu", + "bbox": [ + 511, + 224, + 653, + 238 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abhinav Shrivastava3", + "bbox": [ + 696, + 203, + 867, + 220 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "abhinav@cs.umd.edu", + "bbox": [ + 700, + 224, + 862, + 237 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{1}$ Meta $^{2}$ Johns Hopkins University $^{3}$ University of Maryland, College Park", + "bbox": [ + 181, + 244, + 787, + 265 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 297, + 313, + 314 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "We tackle the challenging task of unsupervised object localization in this work. Recently, transformers trained with self-supervised learning have been shown to exhibit object localization properties without being trained for this task. In this work, we present Multiple Object localization with Self-supervised Transformers (MOST) that uses features of transformers trained using self-supervised learning to localize multiple objects in real world images. MOST analyzes the similarity maps of the features using box counting; a fractal analysis tool to identify tokens lying on foreground patches. The identified tokens are then clustered together, and tokens of each cluster are used to generate bounding boxes on foreground regions. Unlike recent state-of-the-art object localization methods, MOST can localize multiple objects per image and outperforms SOTA algorithms on several object localization and discovery benchmarks on PASCAL-VOC 07, 12 and COCO20k datasets. Additionally, we show that MOST can be used for self-supervised pretraining of object detectors, and yields consistent improvements on fully, semi-supervised object detection and unsupervised region proposal generation. Our project is publicly available at rssaketh.github.io/most.", + "bbox": [ + 76, + 330, + 473, + 664 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 696, + 209, + 710 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Object detectors are important components of several computer vision systems such as visual relationship detection [21, 29], human-object interaction detection [1, 13, 45, 52], scene graph generation [57] and object tracking [54, 56] etc. Performance of object detectors is heavily reliant on the availability of training data. However, annotating large object detection datasets can be expensive and time consuming [14, 27]. Additionally, the vocabulary of object detectors is limited by the training datasets and such detectors often fail to generalize to new cate", + "bbox": [ + 75, + 722, + 468, + 875 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/61a59c0777062ed682651c552f2444d5158933def8ac3fbb7b3e4ec2d73aaffc.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 501, + 297, + 630, + 373 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/7f0260f7fe1aa8978cb4d27127c79235e429d9013382d289a53abe253dc87bb7.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 632, + 297, + 759, + 373 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/023633a71713b03fc570ea1713674f5ad5bdca26457fd2897f6a4d017a80855b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 761, + 297, + 890, + 373 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/e64c0686e63d34c8002db11e89b86fc09c06703053cd1d8941d61f72abf61f30.jpg", + "image_caption": [ + "Figure 1: Top: Methods like LOST [41] (shown in figure), TokenCut [53] identify and localize the most salient foreground object and hence can detect only one object per image. Bottom: MOST is a simple, yet effective method that localizes multiple objects per image without training." + ], + "image_footnote": [], + "bbox": [ + 501, + 377, + 630, + 452 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/e437b7faef62dc1a23f8dfb83d1966fd65a1c3f2b61b8b0d1aee43df4d2f1d54.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 630, + 377, + 759, + 452 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/5c0d0b1c0e8830ff68619378c9935da75155c2ba484d0460a04c23193bd89993.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 761, + 377, + 890, + 452 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "gories [7]. This strategy is not scalable and a more effective approach is warranted. Object discovery is one such task that has the potential to address these concerns. Object discovery is the problem of identifying and grouping objects/parts in a large collection of images without human intervention [23, 24, 36, 43]. The first step in object discovery is to obtain region proposals and subsequently group them semantically. Previous works on discovery used Selective Search [46], randomized Prim's [30] or a region proposal network (RPN) [35] to get object proposals. [48-50] used inter-image similarity to construct a graph and performed optimization or ranking, to localize objects without any supervision. Such methods are computationally expensive and often fail to scale to datasets larger than 20000 images. [34] used region proposals from an RPN and proposed a never ending learning approach and is the first method shown to scale to $\\sim 100000$ images. However, these region proposal methods are often of low quality, and therefore reduce the performance of discovery systems. Recently, LOST [41] and TokenCut [53] leveraged the object segmentation properties of transformers [47] trained using self-supervised learning (DINO [3]) to obtain high quality object proposals. They demonstrate significant improvements over", + "bbox": [ + 496, + 551, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "Work done while at UMD.", + "bbox": [ + 101, + 887, + 243, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "15823", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "state-of-the-art on object discovery, salient object detection and weakly supervised object localization benchmarks.", + "bbox": [ + 76, + 90, + 467, + 119 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "However, both LOST [41] and TokenCut [53] assume the presence of a single salient object per image and hence, can localize only one object as shown in Fig 1 (top). This assumption may hold for object centric datasets like ImageNet [37] but is not true for scene-centric real world datasets like PASCAL-VOC [12] and COCO [27]. In this work, we address the problem of localizing multiple objects per image and demonstrate the effectiveness of our approach for the task of unsupervised object localization and discovery on several standard benchmarks.", + "bbox": [ + 75, + 121, + 467, + 271 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We propose a new object localization method called \"Multiple Object localization with Self-supervised Transformers\" (MOST) which is capable of localizing multiple objects per image without using any labels. We use the features extracted from a transformer [47] network trained with DINO [3]. Our method is based on two empirical observations; 1) Patches within foreground objects have higher correlation with each other than the ones on the background [41] and 2) The similarity map computed using the features of a foreground object with all the features in the image is usually more localized and less noisier than the one computed using the feature of a background. Our algorithm analyzes the similarities between patches exhaustively using a fractal analysis tool called box counting [28]. This analysis picks a set of patches that most likely lie on foreground objects. Next, we perform clustering on the patch locations to group patches belonging to a foreground object together. Each of these clusters is called pools. A binary mask is then computed for each pool and a bounding box is extracted. This capability enables the algorithm to extract multiple bounding boxes per image as shown in Fig.1 (bottom). We demonstrate that without any training, our method can outperform state-of-the-art object localization methods that train class agnostic detectors to detect multiple objects. To prove the effectiveness of MOST, we demonstrate results on several object localization and discovery benchmarks. On self-supervised pre-training for object detectors, using MOST yields consistent improvement across multiple downstream tasks using $6 \\times$ fewer boxes. When compared against other self-supervised transformer-based localization methods, MOST achieves higher recall with and without additional training. We summarize the contributions of our work below.", + "bbox": [ + 75, + 272, + 468, + 770 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose MOST, an effective method to localize and discover multiple objects per image without supervision using transformers trained with DINO.", + "- We perform exhaustive experiments to assess the performance of MOST on several localization and discovery benchmarks and show significant improvements over the baselines." + ], + "bbox": [ + 96, + 784, + 467, + 898 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The paper is organized as follows. In Section 2 we discuss related works on object localization and discovery. We describe our approach in detail in Section 3. We describe our experimental setup and present results in Section 4 and conclude in Section 5.", + "bbox": [ + 498, + 90, + 890, + 165 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Works", + "text_level": 1, + "bbox": [ + 500, + 180, + 648, + 196 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Unsupervised Object Localization and Discovery: Object category discovery can be broadly segregated into image-based [15, 16, 18-20, 42] and region-based methods [4, 8, 22-24, 34, 41, 48-50, 53]. Region-based methods start by generating object proposals and later group them into coherent semantic groups. Image-based approaches on the other hand, assume the localization task to be solved and focus solely on the semantic grouping. Our current method is closer to the former. Vo et al., [48-50] localize regions in images by constructing an inter-image similarity graph between regions and partitioning it using optimization or ranking. Due to the quadratic nature of the graph, these methods cannot scale to large datasets beyond tens of thousands of images. Our current work does not compute inter-image similarity between regions and scales linearly with number of images. Lee et al., [24] propose object graphs that incorporates knowledge about a few known categories to facilitate the discovery of novel categories. MOST doesn't assume any prior knowledge and has the ability to discover objects from scratch. Lee et al., [23] extend object graphs to a curriculum based discovery pipeline, that learns to discover easy objects first and progressively proceeds to discover the harder ones. Along similar lines, Rambhatla et al., [34] propose a large scale discovery pipeline, similar to [24] that leverages prior knowledge about a few categories. Authors of [34] use an RPN [35] trained on known categories as the localization method. In contrast to that, MOST localizes objects in images using features of a transformer [47] trained with DINO [3].", + "bbox": [ + 496, + 205, + 890, + 642 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Object localization using self-supervised networks: Recently, CNNs [17] and Transformers [47] trained in a self-supervised fashion, have been shown to exhibit object localization/segmentation properties [3, 10]. This property is of particular interest as it has the potential to facilitate research on unsupervised localization, detection and segmentation. [41] is a simple method, based on the observation that the key features of the last self attention layer of a transformer, trained using DINO, has certain affinity. They construct a map of inverse degree to extract bounding boxes on objects in an unsupervised fashion. This method is shown to outperform recent state-of-the-art methods by a significant margin. [53] propose an alternate method for localizing objects using self-supervised transformers, based on normalized cut [39]. TokenCut [53] construct an undirected graph based on token feature similarities and use normalized cut to cluster foreground and background patches. SpectralCLUS", + "bbox": [ + 496, + 643, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "15824", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/ca286425971646cacee15f3b712ebf7dc91a261928ce96dc1b494574704b62a4.jpg", + "image_caption": [ + "Figure 2: Motivation for MOST: Example showing similarity maps of tokens within background and foreground for an image from the COCO dataset. Similarity maps of tokens within foreground patches are less random spatially." + ], + "image_footnote": [], + "bbox": [ + 78, + 94, + 468, + 154 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "tering is used to solve the graph-cut and they show that the eigen vector corresponding to the second smallest eigenvalue provides a good cutting solution. TokenCut outperforms LOST on unsupervised object discovery. In addition to discovery, [53] also demonstrate impressive results on unsupervised saliency detection and weakly supervised object localization. Kyriazi et al., [31] propose deep spectral methods, that performs normalized cut [39] but using an affinity matrix computed using semantic and color features. Since this method is very similar to TokenCut and achieves lower performance, we only compare with the latter in this work.", + "bbox": [ + 75, + 251, + 468, + 431 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "However, one limitation of LOST and TokenCut is that they can localize only one object per image. Our proposed method, MOST can automatically localize multiple objects per image and outperforms LOST and TokenCut on standard discovery benchmarks.", + "bbox": [ + 75, + 431, + 468, + 508 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Approach: MOST", + "text_level": 1, + "bbox": [ + 76, + 523, + 254, + 540 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "MOST can be used to localize multiple objects in an image. Our approach, illustrated in Fig. 3, first identifies a set of tokens that is computed from patches on foreground objects. These tokens are then clustered and each cluster, named pool, is used to obtain a bounding box. Next, we discuss a few preliminaries in Section 3.1 followed by the motivation and proposed solution in Section 3.2.", + "bbox": [ + 75, + 547, + 468, + 655 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Preliminaries", + "text_level": 1, + "bbox": [ + 76, + 665, + 217, + 679 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Box Counting: Box counting is a method of analyzing a pattern by breaking and analyzing it at smaller scales. This is done by performing a raster scan of the pattern at different scales and computing appropriate metrics to assess its fractal nature. In this work, we use a sliding window scan.", + "bbox": [ + 75, + 688, + 468, + 762 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Vision Transformers: ViTs [9] operate on learned embeddings, called tokens, generated from non-overlapping image patches of resolution $\\mathrm{P} \\times \\mathrm{P}$ (typically $\\mathrm{P} = 8 / 16$ ) that form a sequence. To be precise, an image $\\mathrm{I}$ of shape $H \\times W \\times 3$ is first divided into non-overlapping patches of resolution $P \\times P \\times 3$ , generating a total of $\\mathrm{N} = HW / P^2$ patches. Next, each patch is embedded via a trainable linear layer to generate a token of dimension $d$ to form a sequence of patches. An extra [CLS] token [6] is added to this sequence, whose", + "bbox": [ + 75, + 763, + 468, + 901 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "purpose is to aggregate the information from the tokens of the sequence. Typically, a projection head is attached to the [CLS] to train the network for classification.", + "bbox": [ + 498, + 90, + 890, + 135 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "DINO: DINO [3] combines self-training and knowledge distillation without labels for self supervised learning. DINO constructs two global views and several local views of lower resolution, from an image. DINO consists of a teacher and a student network. The student processes all the crops while the teacher is operated only on the global crops. The teacher network then distills its dark knowledge to the student. This encourages the student network to learn local to global correspondences. In contrast to other knowledge distillation methods, DINO's teacher network is updated dynamically during training using exponential moving average. DINO was shown to perform on par or better than several baselines on several tasks of image retrieval, copy detection, instance segmentation etc. The property of importance to the current work, is the ability of DINO to localize foreground regions of semantic entities in an image. [41, 53] leverage this property to localize the salient object in an image by using the key features from the last self-attention layer. Similar to [41, 53], we concatenate the key features of all the heads in the last self-attention layer to obtain the input to MOST.", + "bbox": [ + 496, + 136, + 892, + 455 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Multiple object localization", + "text_level": 1, + "bbox": [ + 498, + 465, + 746, + 482 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Motivation: Consider the example shown in Fig. 2. We show three examples of the similarity maps of a token (shown in red) picked on the background (column 2) and foreground (columns 3, 4). Tokens within foreground patches have higher correlation than the ones on background [41]. This results in the similarity maps of foreground patches being less \"spatially\" random than the ones on the background. The task then becomes to analyze the similarity maps and identify the ones with less spatial randomness. Box counting [25, 33] is a popular technique in fractal analysis that analyzes spatial patterns at different scales to extract desired properties. Hence, we adopt box counting for our case and since, we are interested in randomness, we adopt entropy as the metric.", + "bbox": [ + 496, + 489, + 890, + 700 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Preprocessing: The input to our method is a $d$ -dimensional feature $F \\in \\mathbb{R}^{N \\times d}$ , extracted from an image using a neural network. Here, $N$ denotes the number of spatial locations in the feature map, in case of a CNN, or number of tokens, in case of a transformer network. The aim is to identify subsets of tokens, which we call pools, that can be used to localize all the objects in an image. We do not make any assumption on the number of objects present in the image. Given the feature $F$ , we compute an outer product matrix $A = F F^T \\in \\mathbb{R}^{N \\times N}$ . Row $i$ of matrix $A$ , i.e., $A[i,:]$ encodes a similarity map of a token at location $i$ with all the other tokens in $F$ . Next, each row of $A$ is processed by the Entropy-based Box Analysis (EBA) module.", + "bbox": [ + 496, + 702, + 892, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "15825", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/a49e5e55d52837e112a80d00c3e228f880c9ae639797a84ed13c7b4b3663f899.jpg", + "image_caption": [ + "Figure 3: Overview of MOST: MOST operates on features extracted from transformers trained using DINO. The features are used to compute the outer product $A$ . Each row of $A$ is analyzed by the entropy-based box analysis (EBA) module that identifies tokens extracted from foreground patches. These patches are clustered using spatial locations as features to form pools. Each pool is then post-processed to generate a bounding box." + ], + "image_footnote": [], + "bbox": [ + 81, + 92, + 893, + 378 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Entropy-based Box Analysis (EBA): The proposed entropy based box analysis module performs a fractal analysis method, called box counting to segregate similarity maps of tokens on foreground patches from those of background. As shown in Fig. 3, we perform a raster scan with increasing box (used interchangeably with kernel in this work) sizes on each map. Traditionally, measures like lacunarity [44] are computed within each box to analyze the pattern. In this work, we average the elements within each box. This can be implemented efficiently using pooling operations. The resulting downsampled map is flattened and the entropy is computed using the pmf computed as follows: $p(x = x_{i}) = \\sum_{i = 1}^{h.w}\\frac{\\mathbb{1}(f_{i} == x_{i})}{h.w}$ , where $f_{i}$ is the $i^{\\text{th}}$ index in the feature map. A downsampled map belongs to a token on a foreground patch if its entropy is less than a threshold $\\tau$ . Using $K$ boxes in the EBA module results in $K$ entropy values $e_k(k\\in \\{1,2,\\dots ,K\\})$ . Finally, we perform a majority voting among the entropies of all the downsampled maps, i.e., $\\sum_{i = 1}^{K}\\frac{\\mathbb{1}(e_i\\leq\\tau)}{K} >0.5$ , to decide if the original similarity map belongs to a token on a foreground patch. A map of dimension $n\\times n$ has a maximum entropy of $log(n^{2})$ . We use a threshold of the form $\\tau = a + blog(n^{2})$ (we use $a = 1,b = 0.5$ in this work). We do not consider $\\tau$ as a hyperparameter and we pick a value that is mid-way between the minimum and maximum permissible value $(b = 0.5)$ . To prevent a threshold of 0 for $n = 1$ , we add a constant $(a = 1)$ .", + "bbox": [ + 75, + 479, + 472, + 878 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Clustering: The EBA module, identifies a set $S = \\{p|p\\in$", + "bbox": [ + 76, + 883, + 468, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "$\\{1,2,\\dots ,N\\}\\}$ , that contains the spatial locations of tokens computed from foreground patches. Often, highly redundant neighboring tokens are identified. We group neighboring tokens with the help of a clustering step to obtain pools. We convert the linear index $p$ of the tokens to cartesian coordinates $(x,y)$ , and use that as the feature for clustering. Manhattan distance is used as the dissimilarity metric with a threshold $\\epsilon$ ( $\\epsilon = 2$ i.e. Moore neighborhood). Since, the number of pools is not known a-priori, we use a density-based clustering method, DBSCAN [11] which automatically identifies the number of clusters from the data. Pools identified by the clustering step are then post-processed to obtain bounding boxes on foreground objects.", + "bbox": [ + 496, + 479, + 890, + 676 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Post-processing: The clusters, called pools, obtained from the clustering step are then post-processed to obtain one box per pool. Consider $M$ pools identified by the clustering step, i.e. $\\mathcal{C}_i$ , where $i \\in \\{1,2,\\dots M\\}$ . Each pool $\\mathcal{C}_i$ is a set of token locations $\\mathcal{C}_i = \\{p^i | p^i \\in \\{1,2,\\dots ,N\\}\\}$ . We leverage the first observation mentioned above to obtain a bounding box from the pool as follows. First, we build a binary similarity matrix $\\hat{A} = A > 0$ . Next, within the tokens in the pool, we identify the one with lowest degree in $\\hat{A}$ , called the core token, $c^*$ .", + "bbox": [ + 496, + 676, + 892, + 828 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nc ^ {*} = \\underset {c \\in \\mathcal {C} _ {i}} {\\arg \\min } d _ {c} \\quad \\text {w h e r e} \\quad d _ {c} = \\sum_ {j = 1} ^ {N} \\hat {A} [ c, j ]\n$$\n", + "text_format": "latex", + "bbox": [ + 547, + 835, + 841, + 878 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Authors of LOST [41] report that tokens with low degrees", + "bbox": [ + 500, + 885, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "15826", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "table", + "img_path": "images/56e0b5a82b1a077776689ee6e42d4dd46cdb4761d700252291b451568006e5e2.jpg", + "table_caption": [ + "Table 1: Results on unsupervised pre-training of object detectors. We train object detectors in a self-supervised fashion on the COCO dataset using different localization methods and compare their performance on the downstream tasks of semi and fully supervised object detection. COCO train set is used for fine-tuning and $k\\%$ refers to the number of labeled samples used for training. Results are reported using AP[0.50:0.95] (denoted as AP), ${\\mathrm{{AP}}}_{0.50}$ ,and ${\\mathrm{{AP}}}_{0.75}$ on COCO validation set." + ], + "table_footnote": [], + "table_body": "
MethodBoxes per imageVOC 07+12COCO
k=10%fully supervisedk=1%k=2%k=5%fully supervised
APAP50AP75APAP50AP75APAPAP50
LOST [41]140.8860.3144.3663.5883.2770.4812.83 ± 0.3217.23 ± 0.3023.43 ± 0.3844.3062.80
TCut [53]141.1460.5944.3563.7983.5670.7013.13 ± 0.3817.27 ± 0.2123.27 ± 0.2343.8062.30
539.1257.5142.2963.4483.1470.3513.57 ± 0.3817.87 ± 0.3223.17 ± 0.4044.3062.80
SS [46]1040.7660.0044.4664.2383.4471.5513.73 ± 0.2918.00 ± 0.2622.83 ± 0.2543.9062.60
1542.1461.4145.8664.2483.7471.4113.87 ± 0.2918.23 ± 0.4023.13 ± 0.1144.3062.60
MOST4.6543.0363.2946.6164.3484.1271.7713.93 ± 0.3818.13 ± 0.2522.63 ± 0.1144.8063.50
SS3042.1261.2045.7164.8483.9871.7614.47 ± 0.3518.23 ± 0.4223.57 ± 0.2144.0062.30
MOST13.0944.4063.8348.2865.2484.2472.3714.83 ± 0.2118.30 ± 0.1723.43 ± 0.4545.2064.00
", + "bbox": [ + 78, + 160, + 893, + 339 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "most likely fall within an object. Next, we remove the tokens from the pool that do not correlate positively with $c^*$ to form a reduced pool $\\mathcal{C}_i^*$ . This ensures that all the tokens in the current pool lie on the same foreground object. Next, a binary mask is constructed by computing the sum of similarities of token features in $\\mathcal{C}_i^*$ with the features of all the tokens, i.e. $m_k^i = 11(\\sum_{c\\in \\mathcal{C}_i^*}f_k^T f_c\\geq 0)$ . Finally, connected component analysis is performed on the binary mask and the bounding box of the island that contains $c^*$ is selected as the region containing the object. We repeat this process for all the $M$ pools to generate $M$ bounding boxes per image. Note that, $M$ is not assumed to be known a-priori and is decided automatically by our method. Additionally, we remove trivial boxes i.e., boxes which have area less than than a threshold (256) or cover the whole image.", + "bbox": [ + 75, + 364, + 472, + 592 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Implementation Details: For all our experiments, we use the ViT-S/16 and ViT-B/8 [9] models trained with DINO [3] to extract the features. We concatenate the key features of all the heads from the last self-attention layer to use as the input to our method.", + "bbox": [ + 75, + 592, + 472, + 667 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 678, + 209, + 696 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In this section we describe, in detail, the experimental setup used for evaluation. We evaluate our method on two setups, namely the localization setup, and the discovery setup. We begin by describing the datasets and metrics in Sec. 4.1. We describe the evaluation setups in Sec. 4.2. Sec. 4.3 compares our method against contemporary work. We then describe ablation experiments in Sec. 4.4 and show qualitative results in Sec. 4.6.", + "bbox": [ + 75, + 704, + 468, + 825 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Datasets and Metrics", + "text_level": 1, + "bbox": [ + 76, + 832, + 276, + 847 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We use the PASCAL-VOC [12] (2007, 2012 splits) and the COCO [27] (COCO20k [49] and COCO splits) datasets in our experiments. The PASCAL VOC [12] 2007 and 2012", + "bbox": [ + 75, + 854, + 470, + 902 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "trainval sets consists of 5011, 11540 images respectively, spanning twenty objects. The PASCAL VOC [12] test set consists of 4952 images. The COCO [27] 2014 train set consists of $\\sim 110\\mathrm{k}$ images containing over eighty objects and the COCO minimal set consists of 5000 images. We do not use any class or bounding box annotations for our method except for evaluation.", + "bbox": [ + 496, + 364, + 890, + 469 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "For the localization setup, we use the average precision at different thresholds ([0.5:0.95], 0.5 and 0.75), average recall (AR1, AR10 and AR100) and Correct Localization (CorLoc) metrics for evaluation. CorLoc is defined as the fraction of the images in which atleast one object is localized with an IoU greater than a threshold (0.5 in this work). AP, AR are defined in the usual way. For the object discovery setup, we report both the PASCAL VOC style $\\mathrm{AP}_{50}$ and COCO style $\\mathrm{AP}_{[50:95]}$ metrics along with area under the purity-coverage plots [8, 34]. We refer the interested readers to [34] for definitions of purity and coverage.", + "bbox": [ + 496, + 470, + 892, + 638 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Setups", + "text_level": 1, + "bbox": [ + 500, + 650, + 588, + 666 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Localization setup: This setup evaluates the localization performance of methods. We evaluate models on a) unsupervised pre-training, b) Multiple Object Localization, and c) single object localization. For unsupervised pre-training, localization methods are used to train object detectors in an unsupervised fashion and their performance is evaluated on the downstream task of object detection. In this work, we use the recently proposed DETReg [2] as the pre-training strategy which uses a Deformable DeTR [58] architecture. DETReg uses an object localization method and pre-trains an object detector in an unsupervised fashion. We evaluate the pre-trained model on the downstream tasks of semi-supervised, fully-supervised and class-agnostic object proposal generation. In the semi-supervised setting, models are trained on the PASCAL-VOC(07+12) and COCO train", + "bbox": [ + 496, + 674, + 893, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "15827", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/afdd52ed53c2d2404717beab416e7d6db01d1a03ea004ac65559762877a6e973.jpg", + "table_caption": [ + "Table 2: Unsupervised class agnostic region proposal evaluation on COCO validation set: We compare the performance of region proposals for training DETReg. $Rk$ is Recall@k" + ], + "table_footnote": [], + "table_body": "
MethodBoxes per imageAP\\( AP_{50} \\)\\( AP_{75} \\)R1R10R100
LOST [41]10.10.500.41.43.9
TCut [53]10.310.10.61.94.6
50.10.400.114.2
SS [46]100.10.300.11.14.4
150.10.300.114.1
300.10.300.114
MOST4.650.81.410.61.94.4
", + "bbox": [ + 78, + 176, + 323, + 289 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/1a49bd21a5e8010426acf916d24196cd0327a75cc750ec1ff51d77c72436aa87.jpg", + "table_caption": [ + "Table 3: Results on object discovery: Comparison of MOST with recent works on unsupervised object discovery. We experiment with three cluster numbers, i.e., 20, 30, 40, on VOC 2007, 2007+12 and 80, 90, 100 on COCO20k." + ], + "table_footnote": [], + "table_body": "
Metric Train →VOC 2007VOC 07+12COCO20k
Clusters →2030402030408090100
APLOST [41]9.159.6410.1110.9512.1412.972.662.912.86
MOST9.2010.0711.0910.1212.8913.303.133.183.32
AP50LOST [41]26.3227.7829.4629.3533.2734.807.177.727.87
MOST25.3528.1931.3127.0434.4034.548.138.148.76
", + "bbox": [ + 338, + 176, + 655, + 289 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/2ebb2890ec69d5b0157a5bb3503b1c4c941c45417cfb4fe10fb8b72e2f27fb27.jpg", + "table_caption": [ + "Table 4: Results on single-object localization: Comparison of MOST with recent object discovery methods on VOC 07, 12 and COCO20k using CorLoc." + ], + "table_footnote": [], + "table_body": "
MethodVOC 07VOC 12COCO20k
rOSD [49]54.555.348.5
LOD [50]53.655.148.5
DINO-seg† [3]45.846.242.1
LOST [41]61.964.050.7
TokenCut [53]68.872.158.8
LOST [41] + CAD65.770.457.5
TCut [53]+CAD71.475.362.6
MOST74.877.467.1
", + "bbox": [ + 669, + 176, + 898, + 289 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "sets without labels and are fine-tuned on $k\\%$ of labeled data similar to [2]. In the fully supervised setting, pre-trained models are fine-tuned on the full PASCAL-VOC and COCO dataset using all the labels. For the class-agnostic object proposal generation, models are pre-trained on COCO dataset without labels and the generated object proposals are evaluated on the COCO validation set similar to [2].", + "bbox": [ + 73, + 314, + 468, + 419 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We follow the settings used in [50] for multiple-object localization and evaluate on PASCAL-VOC 2007 and COCO20k. For single-object localization, we follow the settings in [41, 53] and evaluate on PASCAL-VOC 2007, PASCAL-VOC 2012 and COCO20k.", + "bbox": [ + 75, + 420, + 468, + 494 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Discovery setup: This setup evaluates the object discovery performance. Similar to [41] we use the regions obtained by our localization method, to perform K-means clustering and use the resulting cluster labels to train Faster-RCNN object detectors on PASCAL-VOC 2007, 2012 trainval and COCO20k train sets. We report results of these experiments on the PASCAL-VOC 2007 test and COCO minival sets respectively. In addition to this, we report the performance of our discovery method on COCO train set, similar to the large scale discovery in [34].", + "bbox": [ + 73, + 496, + 470, + 647 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Comparison with contemporary methods", + "text_level": 1, + "bbox": [ + 76, + 654, + 429, + 671 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this section we compare our method against contemporary works the localization and discovery setups.", + "bbox": [ + 75, + 678, + 468, + 709 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3.1 Localization setup", + "text_level": 1, + "bbox": [ + 75, + 724, + 259, + 742 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Unsupervised Pre-training: Table 1 compares the results of all the localization methods on unsupervised pre-training of object detectors. We use average precision at different IoU thresholds ([0.50:0.95]: AP, 0.5: $\\mathrm{AP}_{0.50}$ , 0.75: $\\mathrm{AP}_{0.75}$ ) for evaluation. On the semi-supervised setting, on VOC $07 + 12$ ( $k = 10\\%$ ), the self-supervised transformer based methods (LOST, TokenCut and MOST) outperform SS [46] with fewer boxes per image. In particular, TokenCut (denoted as TCut in Table 1) which outputs only one box per image, outperforms SS, using ten boxes per image, by $\\sim 0.4$", + "bbox": [ + 73, + 750, + 472, + 902 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "points on mAP. MOST which outputs an average of 4.65 boxes per image outperforms TokenCut (the best performing self-supervised transformer based method) by 1.89, 2.7 and 2.26 percentage points on AP, $\\mathrm{AP}_{50}$ , and $\\mathrm{AP}_{75}$ respectively. This can be attributed to the ability of MOST to output multiple foreground regions resulting in more samples for pre-training which is not possible in the case of TokenCut. MOST outperforms SS, that outputs 30 boxes per image, by 0.91, 2.09 and 0.9 points on AP, $\\mathrm{AP}_{50}$ , and $\\mathrm{AP}_{75}$ respectively using almost $6\\times$ fewer boxes per image and this can be attributed to the ability of MOST to generate high quality proposals. On COCO, MOST outperforms TokenCut by 0.8 and 0.86 on the $1\\%$ and $2\\%$ setting of semi-supervised learning. MOST with a ViT-B/8 backbone, that outputs 13.09 boxes on average per image, outperforms SS (with 30 boxes per image) by 0.36, 0.07 points on $k = 1\\%$ and $k = 2\\%$ few shot splits of COCO respectively.", + "bbox": [ + 496, + 314, + 893, + 571 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "On the fully supervised setting, MOST outperforms LOST and TokenCut by 0.76 and 0.55 (AP) percentage points respectively on VOC 07+12. On COCO, MOST outperforms them by 0.50 and 1 points respectively. On VOC 07+12, MOST using ViT-B/8 (13.09 boxes per image) outperforms SS (with 30 boxes per image) by 0.40. On the much harder COCO dataset, MOST outperforms SS 1.20 (AP) percentage points using $2 \\times$ fewer boxes per image.", + "bbox": [ + 496, + 577, + 893, + 700 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In Table 2 we report the class agnostic object proposal evaluation of DETReg trained using different localization methods. We report average precision at different IoU thresholds (AP, $\\mathrm{AP}_{50}$ , $\\mathrm{AP}_{75}$ ) and recall @ 1, 10 and 100 proposals per image (denoted as R1, R10, and R100) to evaluate the quality of region proposals. Note that the numbers in the table are low because of the unsupervised nature of training. All the self-supervised transformer-based methods achieve performance better than SS with far fewer boxes. In recall, TokenCut and MOST perform on par with each other and outperform rest of the methods with significant improvements. MOST achieves the highest performance on average precision among all the methods. It can achieve", + "bbox": [ + 496, + 704, + 895, + 901 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "15828", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/1812c514a3ca58d091197293527d3af10209491e8a4512da568b8e75248587b2.jpg", + "image_caption": [ + "k=1" + ], + "image_footnote": [], + "bbox": [ + 80, + 88, + 212, + 152 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/5cef825af556d0688bd363a529c893966dc46af3dc0c484aea1fb9feaf41ee01.jpg", + "image_caption": [ + "k=3" + ], + "image_footnote": [], + "bbox": [ + 215, + 88, + 349, + 152 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/becec42406bb0a5294841aa92dfa23a4be362abcfec37a51051330d13912d091.jpg", + "image_caption": [ + "k=5" + ], + "image_footnote": [], + "bbox": [ + 351, + 88, + 486, + 152 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/6b54989c587365291834c1b104435a165a3e025e14a4e77453cd7e72a2b89a98.jpg", + "image_caption": [ + "k=1" + ], + "image_footnote": [], + "bbox": [ + 80, + 169, + 212, + 242 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/2444333a3d0e9c4b53c1d9ad7736497c9ddcaf41b4b42c32d2c0bbd8398d68ed.jpg", + "image_caption": [ + "k=2" + ], + "image_footnote": [], + "bbox": [ + 215, + 169, + 349, + 242 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1ff923ab289a6f553b4149f73dd92552d11ca6d8600f37d309c55b6a1e606b26.jpg", + "image_caption": [ + "k=3" + ], + "image_footnote": [], + "bbox": [ + 351, + 169, + 486, + 242 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "higher precision and recall because of its ability to output multiple high quality regions per image. While LOST and TokenCut output high quality boxes, they cannot output more than one box per image. SS on the other hand, outputs multiple boxes but with poor quality.", + "bbox": [ + 75, + 356, + 468, + 431 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Multiple Object Localization: We compare with LOD, the state-of-the-art method on the multi-object localization benchmark proposed by LOST using the code released by authors. On VOC2007, we attain an odAP[0.5:0.95] of 6.43 compared to 5.35 attained by LOD, an improvement of 1.09 percentage points. On the COCO20k dataset, we attain a performance of 1.70 (compared to 1.53 achieved by LOD) on the harder odAP[0.50:0.95] metric. Note, we do not compare with rOSD [49] as LOD [50] outperforms it.", + "bbox": [ + 75, + 431, + 468, + 568 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Single Object Localization: Table 4 compares the results of our method on single object localization with recent methods on PASCAL VOC 2007, 2012 and COCO20k respectively. We use the CorLoc metric to evaluate methods. Note that MOST is a multiple object localization method and this setup evaluates the ability of methods to output a single region. Since MOST outputs multiple boxes, we use the heuristic, average best overlap (for evaluating object proposals in [46]), to select one region per image. The numbers reported for MOST in this table are the \"best\" case scenario. We outperform LOST by 12.9, 13.4 and 16.4 percentage points on VOC 2007, 2012 and COCO20k respectively. We outperform TokenCut [53] by 6, 5.3 and 8.3 percentage points on the three datasets respectively. To obtain multiple regions per image, authors of LOST train a foreground object detector using the regions obtained by their method as supervision, called LOST+CAD [41]. This method can output multiple boxes per image and from Table 4, even without any training, our method outperforms LOST+CAD and TokenCut+CAD by 9.1, 7, 9.6 and 3.4, 2.1, 4.5 percentage points on VOC 2007, 2012 and COCO20k respectively.", + "bbox": [ + 75, + 568, + 468, + 901 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/010347b59054872fef604556ece16985ab91d6365d4ca175344e727748b5dd51.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 500, + 88, + 700, + 172 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/4f7ae4bfa2cbc7382b89e488d51cd4abedb920a2cbf08157c833d2ddb57cd7e8.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 705, + 88, + 906, + 172 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/525d2ac72d6b24c4c0623acf84b0c63b906b8b377cbec83fc10c3e431982134e.jpg", + "image_caption": [ + "Figure 4: Effect of kernel size: Different kernel sizes can identify different tokens as belonging to the foreground. Multiple kernels help eliminate noisy predictions (first triplet) and missed predictions (second triplet).", + "Figure 5: Figure demonstrating the effect of clustering in MOST: Each image consists of a bounding box generated from a pool. We observe that each pool focuses on different foreground instance." + ], + "image_footnote": [], + "bbox": [ + 500, + 174, + 700, + 258 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/480e4d325d6557577d4d05c05a5fc987019fb8b3a6f6305cd1b54517085c7ac4.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 705, + 174, + 906, + 258 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/f4fda4b897aeb4e8590f31d2437da3f249e09a39aecee38cfb45a2e124e1f5fe.jpg", + "image_caption": [ + "Figure 6: Figure demonstrating the effect of clustering in MOST. Eliminating the clustering results in noisier outputs." + ], + "image_footnote": [], + "bbox": [ + 501, + 353, + 599, + 409 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/26ff3ae1e3c2dc6a1b0328cb2381d62833af696b2f4a15af57e17d84e1b132f7.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 599, + 353, + 694, + 409 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/03da880ef6407f4afd06eef657b13ebcc2340098742602d56df19d668b0975dd.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 697, + 353, + 792, + 409 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/409d4e0ba1560f9f508de4c72407b3ee65add926faf33788dc51474bba082699.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 794, + 353, + 890, + 409 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Discovery Setup: This setup evaluates the true object discovery performance as the localized boxes are used to discover semantic groups. Following LOST [41], we first cluster the features of the localized objects using K-means clustering. For VOC 2007 and $2007 + 2012$ trainval splits, we use 20, 30 and 40 clusters. We use 80, 90 and 100 clusters for COCO20k train split. We report the results of experiments on VOC 2007, $07 + 12$ trainval sets on VOC 2007 test set. For experiments on COCO20k, we report results on the COCO validation set. Results are tabulated in Table 3. MOST outperforms LOST in most settings with the margin of improvement higher for more number of clusters and more cluttered datasets like COCO. For more details on clustering and training refer to supplementary.", + "bbox": [ + 496, + 488, + 890, + 699 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Finally, we evaluate the performance of MOST on large-scale object discovery setup introduced in [34]. For this setup, we use the area under the purity coverage plot as the metric. [34] automatically identifies the number of clusters and obtains an AuC@0.5 of $3.6\\%$ on the COCO 2014 train set. We extract the DINO [CLS] token features of regions obtained from MOST for K-Means clustering. To avoid specifying the number of clusters manually, we employ the \"kneedle\" method [38] to get the optimal number of clusters (more details in supplementary). Next, we randomly sample 10000 features from the whole dataset and cluster them using K-means with the optimal number of clusters. This subsampling avoids loading all the features into mem", + "bbox": [ + 496, + 704, + 892, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "15829", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/af60b2091b25194435a10fdb72d50c7ae4dd7351552d05fff911fbaf9add310c.jpg", + "image_caption": [ + "Figure 7: Recall analysis: Comparison of recall values of MOST, MOST+CAD with LOST and LOST+CAD. LOST generates one bounding box per image. MOST+CAD, MOST have higher recall and cover more ground-truth objects for a fixed set of boxes." + ], + "image_footnote": [], + "bbox": [ + 83, + 90, + 464, + 223 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "ory. MOST + optimal K-means achieves an AuC@0.5 of $8.74\\%$ on COCO 2014 train set. We use the cluster labels to train an object detector on the COCO train set and achieve an $\\mathrm{AP / AP}_{50}$ of $3.9 / 9.5\\%$ compared to $5.2\\%$ $\\mathrm{AP}_{50}$ obtained by [34] on COCO validation set. For more experiments on unsupervised saliency detection and weakly supervised localization, refer to the supplementary.", + "bbox": [ + 75, + 339, + 468, + 445 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.4. Ablation Experiments", + "text_level": 1, + "bbox": [ + 76, + 454, + 282, + 469 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Effect of kernel size: The EBA module performs box analysis in a sliding window fashion using boxes (or kernels) of different sizes. We implement this efficiently using a pooling operation. We visualize the effect of the size of pooling kernels on the final output in Fig. 4. We observe that the majority voting performed in EBA, helps in removing noisy predictions in the first triplet, where a box identified by kernel of size 1 is eliminated by majority voting of kernels with larger receptive field. In the second triplet in Fig. 4, an object which was missed by the lower order kernels $(\\mathrm{k} = [1,4])$ , can be picked up with a higher order kernel $(\\mathrm{k} = 5)$ . For all our experiments, we use kernels of sizes upto 5 (i.e. $\\mathrm{k} = [1,5]$ ). For quantitative results on the effect of kernel sizes, refer to the supplementary.", + "bbox": [ + 75, + 477, + 468, + 688 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Effect of clustering: MOST performs clustering with the token locations as features to obtain pools. Each pool contains tokens belonging to a foreground object. We show the effect of clustering qualitatively in Fig. 5. We observe that each pool focuses on one foreground object and illustrate the bounding boxes extracted from each pool.", + "bbox": [ + 75, + 688, + 468, + 779 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Each pool contains tokens belonging to a foreground object. We show the effect of forming pools qualitatively in Fig. 6. The first image in each pair shows the output of MOST without clustering to form pools and the second image shows the output with the formation. We observe that, without clustering, each token can generate a bounding box resulting in noisier outputs.", + "bbox": [ + 75, + 779, + 468, + 885 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Recall of boxes: To analyze the object localization perfor", + "bbox": [ + 76, + 885, + 468, + 901 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/24934d015d4dfe64678d1bae29d424bdbe1afcc4531cf6e1400344ac5458304b.jpg", + "table_caption": [ + "Table 5: Effect of backbone on single-object localization" + ], + "table_footnote": [], + "table_body": "
BackboneVOC 2007VOC 2012COCO20k
ViT-S/884.2586.0080.50
ViT-S/1674.8077.4068.60
ViT-B/885.4087.0081.73
ViT-B/1672.7276.2867.20
", + "bbox": [ + 563, + 114, + 828, + 204 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "mance of MOST, we compare its recall with LOST and TokenCut on VOC 07, 12 and COCO20k datasets in Fig. 7. The x-axis represents the maximum number of boxes allowed per image and the y axis plots the recall. LOST and TokenCut generate only one box per image and hence have fixed recall in all the plots. MOST can generate more boxes and hence have higher recall than LOST and TokenCut. [41] trains a class agnostic detector (CAD) to output multiple boxes per image using the output of LOST as supervision. Without a single step of training, MOST performs competitively against LOST+CAD on all the datasets. With a class agnostic detector, MOST+CAD outperforms LOST, TokenCut and their CAD counterparts comfortably on all the datasets. On COCO20k, a much harder dataset, MOST+CAD outperforms all the methods with a significant margin demonstrating its superior localization abilities.", + "bbox": [ + 496, + 231, + 890, + 487 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Effect of EBA: We study the effect of EBA on single-object localization. The task of the EBA module is to identify tokens on foreground instances from similarity maps. We replace the EBA module with the strategy used by LOST [41], effectively giving LOST the ability to localize multiple objects. We use top-100 patches and this system achieves a CorLoc of 63.66 (compared to 74.84 of MOST). The EBA module can automatically pick the right tokens, unlike LOST to localize multiple objects. This experiment demonstrates the benefit of the proposed EBA module.", + "bbox": [ + 496, + 489, + 890, + 641 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Timing analysis: MOST can localize multiple objects per image and does so by analyzing the similarity maps of all the tokens which is computationally more expensive. To understand this requirement, we perform a timing analysis. On average, LOST takes 0.008s per image while MOST takes 0.3s. MOST obtains a recall of 0.19, 0.21, and 0.08 on VOC07, VOC12, and COCO20k respectively (compared to 0.13, 0.15, and 0.03 of LOST). This translates to localizing an additional 750, 2400, and 7200 instances than LOST on VOC07, VOC12, and COCO20k respectively. We believe the additional time taken by MOST is justified by the improvement in recall performance which is essential for an object localization method.", + "bbox": [ + 496, + 642, + 890, + 837 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Effect of backbone: We study the effect of backbone on MOST in Table 5. We observe that backbones with a smaller patch size can localize more objects, especially smaller ones (refer to supplementary for qualitative results)", + "bbox": [ + 496, + 839, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "15830", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/0aff19d213a50846bc9baab00f055f202ab4631c7d08ca181a3506ac8ee550d5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 84, + 88, + 215, + 157 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/1aa69e756f27a3c28756b6a3ce7627c833f3a4f16b977bcf587e18d6a49c1dcc.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 217, + 88, + 341, + 157 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/e93b608b8f73d927ad44349baa5df2eef466966e078b3a80bd631b77b906a0e4.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 341, + 88, + 482, + 157 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/fef149cf998a49f473e54abd7407ee942bf6475d9598c03a7716cad7fbfdae42.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 483, + 88, + 549, + 157 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/261952cba14f3e6bc96bd1ff5969acd501d588a312643ee40d19633c27a5bba5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 550, + 88, + 678, + 157 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/a900dbf02e419bf63da109f5f49292f67c8f1d84130624bd2a63d667b9001060.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 679, + 88, + 751, + 157 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/a8e2c006c95c3b07b22dc9959dff16dc33a6c8eb9fb5cc9e504ad29c41beec49.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 751, + 88, + 883, + 157 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/235f62354645ddafbf698dc5ebae130d5d6733189102d6d48a7374453ddaf205.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 84, + 160, + 217, + 229 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/27af0758d2f87a029aff3ab79076317d5e0a9f218945d99326e376020f973dce.jpg", + "image_caption": [ + "(a) VOC 07+12" + ], + "image_footnote": [], + "bbox": [ + 220, + 160, + 349, + 229 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/087da7178ef671c5d2e5f47c8f7fb7ed50313d4407cb5e939b3ffb9303c488ed.jpg", + "image_caption": [ + "Figure 8: Qualitative results of MOST on VOC 07, 12 and COCO: MOST can localize multiple objects in cluttered scenes without training. Localization ability of MOST is not limited by the biases of annotators and can localize rocks, mountains, branches, water bodies, etc." + ], + "image_footnote": [], + "bbox": [ + 351, + 160, + 482, + 229 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/8e57c3b2f8693e9c9af96d34a03291c0db18f338f42ed2a256f057b8bbd16b47.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 483, + 160, + 616, + 229 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/59139d447aa3fddc3d05bb8092541a23300a49e41a88f74b1737249351c3664d.jpg", + "image_caption": [ + "(b) COCO" + ], + "image_footnote": [], + "bbox": [ + 617, + 160, + 750, + 229 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/0f8107af5ca39d2fee6a948fc7de1a365c7a8ba61acf60733d4d0267af3fbcbd.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 751, + 160, + 883, + 229 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/2f9e794ab029f0990907d7f5242cdb8d8c799bf1b35dbe92b2efcebbd72ff55e.jpg", + "table_caption": [ + "Table 6: Results on unsupervised saliency detection: We compare MOST to state-of-the-art unsupervised saliency detections methods. Top results are in bold and second best is highlighted in blue. Ability to detect multiple objects in images is a good tradeoff for a slight drop in performance on saliency detection" + ], + "table_footnote": [], + "table_body": "
MethodECSSDDUTSDUT-OMRON
max Fβ IoU Acc (%)max Fβ IoU Acc (%)max Fβ IoU Acc (%)
DeepUSPS[32]58.444.079.542.530.577.341.430.577.9
BigBiGAN [51]78.267.289.960.849.887.854.945.385.6
E-BigBiGAN [51]79.768.490.662.451.188.256.346.486.0
LOST [41]75.762.588.061.852.087.147.440.279.6
TCut [53]80.371.291.867.257.690.360.053.388.0
MOST79.163.189.066.653.889.757.047.587.0
", + "bbox": [ + 78, + 416, + 468, + 549 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "resulting in a higher CorLoc. This comes at a cost of producing noisier outputs. We refer interested readers to the supplementary for more analysis and qualitative results on the effect of backbones and patch sizes.", + "bbox": [ + 75, + 558, + 468, + 619 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "4.5. Additional Experiments", + "text_level": 1, + "bbox": [ + 76, + 633, + 297, + 648 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Unsupervised Saliency Detection: MOST can easily be extended to unsupervised saliency detection. We experiment with ECSSD [40], DUTS [26] and DUT-OMRON [5] datasets and use the metrics used by [41, 53] for evaluation. All these datasets require methods to segment the salient object in an image. Hence, naively using MOST doesn't perform well. To extend MOST for saliency detection, we select the largest pool and use the similarity map computed using its tokens as the saliency map. In Table 6, we compare MOST with TokenCut and LOST on the three datasets. MOST outperforms LOST comfortably on all the metrics, datasets and fares competitively against TokenCut. We believe that the ability to detect multiple objects in images is a good tradeoff for a slight drop in performance on saliency detection. We refer interested readers to the supplementary for qualitative results on saliency detection.", + "bbox": [ + 75, + 657, + 468, + 900 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Weakly supervised localization: We evaluate MOST on weakly supervised object localization on CUB-200 [55] and Imagenet [37] datasets respectively, and achieve a CorLoc of 92.42 (vs. 91.8 of TokenCut) on CUB-200 and a CorLoc of 71.4 (vs. 65.4 of TokenCut).", + "bbox": [ + 496, + 314, + 890, + 391 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "4.6. Qualitative Results:", + "text_level": 1, + "bbox": [ + 500, + 398, + 687, + 415 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We illustrate qualitative results of MOST on VOC2007, 2012 and COCO datasets in Fig. 8. Fig. 8a shows results on VOC 2007 and 2012 and Fig. 8b shows results on COCO dataset. MOST is capable of localizing fairly complex scenes in all the three datasets. We observe that, such unsupervised localization methods are not limited by the categories annotated by humans but can localize regions of \"stuff\" like sign boards (third image in the first row of Fig. 8a right), rocks (last image of last row in Fig. 8b), and water bodies (first image in second row of Fig. 8b).", + "bbox": [ + 496, + 421, + 890, + 573 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 585, + 617, + 599 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We present MOST, an effective method for localizing multiple objects in complex images without a single annotation. MOST leverages object segmentation properties of transformers trained using DINO [3]. We show that the ability of MOST to localize multiple objects in an image is very effective on several object localization and discovery benchmarks. In particular, MOST outperforms recent state-of-the-art methods that train a class agnostic detector, on the task of single object localization, without any training. Further, we show that MOST achieves higher recall and covers more ground truth objects for a fixed set of boxes than LOST [41], a contemporary work on object localization. Finally, we extend MOST to the task of unsupervised saliency detection and report competitive results with recent works.", + "bbox": [ + 496, + 609, + 890, + 821 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement. This project was partially supported by DARPA SemaFor (HR001119S0085) and DARPA SAIL-ON (W911NF2020009), and Amazon Research Award to Abhinav Shrivastava. Rama Chellappa was supported by an ONR MURI (N00014-20-1-2787).", + "bbox": [ + 496, + 824, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "15831", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 174, + 106 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Ankan Bansal, Sai Saketh Rambhatla, Abhinav Shrivastava, and Rama Chellappa. Detecting human-object interactions via functional generalization. Thirty-Fourth AAAI Conference on Artificial Intelligence, 2020. 1", + "[2] Amir Bar, Xin Wang, Vadim Kantorov, Colorado J Reed, Roei Herzig, Gal Chechik, Anna Rohrbach, Trevor Darrell, and Amir Globerson. Detreg: Unsupervised pretraining with region priors for object detection, 2021. 5, 6", + "[3] Mathilde Caron, Hugo Touvron, Ishan Misra, Hervé Jégou, Julien Mairal, Piotr Bojanowski, and Armand Joulin. Emerging properties in self-supervised vision transformers. In Proceedings of the International Conference on Computer Vision (ICCV), 2021. 1, 2, 3, 5, 6, 9", + "[4] Minsu Cho, Suha Kwak, Cordelia Schmid, and Jean Ponce. Unsupervised Object Discovery and Localization in the Wild: Part-based Matching with Bottom-up Region Proposals. In CVPR - IEEE Conference on Computer Vision & Pattern Recognition, pages 1201-1210, Boston, United States, June 2015. IEEE. 2", + "[5] Yang Chuan, Zhang Lihe, Lu Huchuan Ruan Xiang, and Yang Ming-Hsuan. Saliency detection via graph-based manifold ranking. In Computer Vision and Pattern Recognition (CVPR), 2013 IEEE Conference on, pages 3166-3173. IEEE, 2013. 9", + "[6] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. BERT: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers), pages 4171–4186, Minneapolis, Minnesota, June 2019. Association for Computational Linguistics. 3", + "[7] Akshay Dhamija, Manuel Gunther, Jonathan Ventura, and Terrance Boult. The overlooked elephant of object detection: Open set. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision (WACV), March 2020. 1", + "[8] Carl Doersch, Abhinav Gupta, and Alexei A. Efros. Context as supervisory signal: Discovering objects with predictable context. In European Conference on Computer Vision (ECCV), pages 362-377. Springer, 2014. 2, 5", + "[9] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. ICLR, 2021. 3, 5", + "[10] Debidatta Dwibedi, Yusuf Aytar, Jonathan Tompson, Pierre Sermanet, and Andrew Zisserman. With a little help from my friends: Nearest-neighbor contrastive learning of visual representations. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 9588–9597, October 2021. 2", + "[11] Martin Ester, Hans-Peter Kriegel, Jörg Sander, and Xiaowei Xu. A density-based algorithm for discovering clusters in large spatial databases with noise. In Proceedings of the Second International Conference on Knowledge Discovery and" + ], + "bbox": [ + 76, + 114, + 470, + 892 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Data Mining, KDD'96, page 226-231. AAAI Press, 1996. 4", + "[12] Mark Everingham, Luc Van Gool, Christopher K. I. Williams, John Winn, and Andrew Zisserman. The pascal visual object classes (voc) challenge. International Journal of Computer Vision, 88(2):303-338, 2010. 2, 5", + "[13] Georgia Gkioxari, Ross B. Girshick, Piotr Dólar, and Kaiming He. Detecting and recognizing human-object interactions. 2018 IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8359-8367, 2018. 1", + "[14] Agrim Gupta, Piotr Dollar, and Ross Girshick. LVIS: A dataset for large vocabulary instance segmentation. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2019. 1", + "[15] Kai Han, Sylvestre-Alvise Rebuffi, Sebastien Ehrhardt, Andrea Vedaldi, and Andrew Zisserman. Automatically discovering and learning new visual categories with ranking statistics. In Proceedings of the International Conference on Learning Representations (ICLR), 2020. 2", + "[16] Kai Han, Andrea Vedaldi, and Andrew Zisserman. Learning to discover novel visual categories via deep transfer clustering. In Proceedings of the International Conference on Computer Vision (ICCV), 2019. 2", + "[17] Kaiming He, X. Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 770-778, 2016. 2", + "[18] Yen-Chang Hsu, Zhaoyang Lv, and Zsolt Kira. Deep image category discovery using a transferred similarity function. CoRR, abs/1612.01253, 2016. 2", + "[19] Yen-Chang Hsu, Zhaoyang Lv, and Zsolt Kira. Learning to cluster in order to transfer across domains and tasks. In 6th International Conference on Learning Representations, ICLR 2018, Vancouver, BC, Canada, April 30 - May 3, 2018, Conference Track Proceedings, 2018.", + "[20] Yen-Chang Hsu, Zhaoyang Lv, Joel Schlosser, Phillip Odom, and Zsolt Kira. Multi-class classification without multi-class labels. In 7th International Conference on Learning Representations, ICLR 2019, New Orleans, LA, USA, May 6-9, 2019, 2019. 2", + "[21] Ranjay Krishna, Yuke Zhu, Oliver Groth, Justin Johnson, Kenji Hata, Joshua Kravitz, Stephanie Chen, Yannis Kalantidis, Li-Jia Li, David A. Shamma, Michael S. Bernstein, and Li Fei-Fei. Visual genome: Connecting language and vision using crowdsourced dense image annotations. International Journal of Computer Vision, 123:32-73, 2016. 1", + "[22] Suha Kwak, Minsu Cho, Ivan Laptev, Jean Ponce, and Cordelia Schmid. Unsupervised Object Discovery and Tracking in Video Collections. In ICCV - IEEE International Conference on Computer Vision, pages 3173-3181, Santiago, Chile, Dec. 2015. IEEE. 2", + "[23] Y. J. Lee and K. Grauman. Object-graphs for context-aware category discovery. In 2010 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 1-8, June 2010. 1, 2", + "[24] Yong Jae Lee and Kristen Grauman. Learning the easy things first: Self-paced visual category discovery. In CVPR, pages 1721-1728. IEEE, 2011. 1, 2", + "[25] Jian Li, Qian Du, and Caixin Sun. An improved box-counting method for image fractal dimension estimation." + ], + "bbox": [ + 503, + 92, + 890, + 892 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "15832", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Pattern Recognit., 42:2460-2469, 2009. 3", + "[26] Wang Lijun, Lu Huchuan, Wang Yifan, Feng Mengyang, Wang Dong, Yin Baocai, and Ruan Xiang. Learning to detect salient objects with image-level supervision. In CVPR, 2017. 9", + "[27] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólár, and C. Lawrence Zitnick. Microsoft coco: Common objects in context. In David Fleet, Tomas Pajdla, Bernt Schiele, and Tinne Tuytelaars, editors, Computer Vision – ECCV 2014, pages 740–755, Cham, 2014. Springer International Publishing. 1, 2, 5", + "[28] Jing Z. Liu, Luduan Zhang, and Guang H. Yue. Fractal dimension in human cerebellum measured by magnetic resonance imaging. Biophysical journal, 85 6:4041-6, 2003. 2", + "[29] Cewu Lu, Ranjay Krishna, Michael Bernstein, and Li Fei-Fei. Visual relationship detection with language priors. In European Conference on Computer Vision, 2016. 1", + "[30] Santiago Manen, Matthieu Guillaumin, and Luc Van Gool. Prime object proposals with randomized prim's algorithm. In 2013 IEEE International Conference on Computer Vision, pages 2536-2543, 2013. 1", + "[31] Luke Melas-Kyriazi, Christian Rupprecht, Iro Laina, and Andrea Vedaldi. Deep spectral methods: A surprisingly strong baseline for unsupervised semantic segmentation and localization. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 3", + "[32] Duc Tam Nguyen, Maximilian Dax, Chaithanya Kumar Mummadi, Thi-Phuong-Nhung Ngo, Thi Hoai Phuong Nguyen, Zhongyu Lou, and Thomas Brox. Deepusps: Deep robust unsupervised saliency prediction with self-supervision. In NeurIPS, 2019. 9", + "[33] Roy E Plotnick, Robert H Gardner, William W Hargrove, Karen Prestegaard, and Martin Perlmutter. Lacunarity analysis: a general technique for the analysis of spatial patterns. Physical review E, 53(5):5461, 1996. 3", + "[34] Sai Saketh Rambhatla, Ramalingam Chellappa, and Abhinav Shrivastava. The pursuit of knowledge: Discovering and localizing novel categories using dual memory. 2021 IEEE/CVF International Conference on Computer Vision (ICCV), pages 9133-9143, 2021. 1, 2, 5, 6, 7, 8", + "[35] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. In C. Cortes, N. D. Lawrence, D. D. Lee, M. Sugiyama, and R. Garnett, editors, Advances in Neural Information Processing Systems 28, pages 91-99. Curran Associates, Inc., 2015. 1, 2", + "[36] Alvaro Collet Romea, Bo Xiong, Corina Gurau, Martial Hebert, and Siddhartha Srinivasa. Herbdisc: Towards lifelong robotic object discovery. In Proceedings of International Journal of Robotics Research (IJRR), January 2014. 1", + "[37] Olga Russakovsky, Jia Deng, Hao Su, Jonathan Krause, Sanjeev Satheesh, Sean Ma, Zhiheng Huang, Andrej Karpathy, Aditya Khosla, Michael Bernstein, Alexander C. Berg, and Li Fei-Fei. ImageNet Large Scale Visual Recognition Challenge. International Journal of Computer Vision (IJCV), 115(3):211-252, 2015. 2, 9", + "[38] Ville Satopaa, Jeannie Albrecht, David Irwin, and Barath" + ], + "bbox": [ + 78, + 92, + 468, + 892 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Raghavan. Finding a \"kneedle\" in a haystack: Detecting knee points in system behavior. In 2011 31st International Conference on Distributed Computing Systems Workshops, pages 166-171, 2011. 7", + "[39] Jianbo Shi and Jitendra Malik. Normalized cuts and image segmentation. Proceedings of IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 731-737, 1997. 2, 3", + "[40] Jianping Shi, Qiong Yan, Li Xu, and Jiaya Jia. Hierarchical image saliency detection on extended cssd. IEEE Transactions on Pattern Analysis and Machine Intelligence, 38:717-729, 2016. 9", + "[41] Oriane Simeoni, Gilles Puy, Huy V. Vo, Simon Roburin, Spyros Gidaris, Andrei Bursuc, Patrick Pérez, Renaud Marlet, and Jean Ponce. Localizing objects with self-supervised transformers and no labels. In Proceedings of the British Machine Vision Conference (BMVC), November 2021. 1, 2, 3, 4, 5, 6, 7, 8, 9", + "[42] Krishna Kumar Singh, Utkarsh Ojha, and Yong Jae Lee. Finegan: Unsupervised hierarchical disentanglement for fine-grained object generation and discovery. In CVPR, 2019. 2", + "[43] J. Sivic, B. C. Russell, A. A. Efros, A. Zisserman, and W. T. Freeman. Discovering objects and their location in images. In Tenth IEEE International Conference on Computer Vision (ICCV'05) Volume 1, volume 1, pages 370-377 Vol. 1, Oct 2005. 1", + "[44] T. G. Smith, G. D. Lange, and W. B. Marks. Fractal methods and results in cellular morphology — dimensions, lacunarity and multifractals, Nov. 1996. 4", + "[45] Masato Tamura, Hiroki Ohashi, and Tomoaki Yoshinaga. Qpic: Query-based pairwise human-object interaction detection with image-wide contextual information. 2021 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 10405-10414, 2021. 1", + "[46] J.R.R. Uijlings, K.E.A. van de Sande, T. Gevers, and A.W.M. Smeulders. Selective search for object recognition. International Journal of Computer Vision, 2013. 1, 5, 6, 7", + "[47] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Proceedings of the 31st International Conference on Neural Information Processing Systems, NIPS'17, page 6000-6010, Red Hook, NY, USA, 2017. Curran Associates Inc. 1, 2", + "[48] Huy V. Vo, Francis Bach, Minsu Cho, Kai Han, Yann LeCun, Patrick Pérez, and Jean Ponce. Unsupervised image matching and object discovery as optimization. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 8287-8296, 2019. 1, 2", + "[49] Huy V. Vo, Patrick Pérez, and Jean Ponce. Toward unsupervised, multi-object discovery in large-scale image collections. In Proceedings of the European Conference on Computer Vision (ECCV), 2020. 5, 6, 7", + "[50] Huy V. Vo, Elena Sizikova, Cordelia Schmid, Patrick Pérez, and Jean Ponce. Large-scale unsupervised object discovery. In Advances in Neural Information Processing Systems 34 (NeurIPS), 2021. 1, 2, 6, 7", + "[51] Andrey Voynov, Stanislav Morozov, and Artem Babenko." + ], + "bbox": [ + 501, + 92, + 890, + 892 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "15833", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Object segmentation without labels with large-scale generative models. In ICML, 2021. 9", + "[52] Tiancai Wang, Tong Yang, Martin Danelljan, Fahad Shahbaz Khan, X. Zhang, and Jian Sun. Learning human-object interaction detection using interaction points. 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4115-4124, 2020. 1", + "[53] Yangtao Wang, Xi Shen, Shell Xu Hu, Yuan Yuan, James Crowley, and Dominique Vaufreydaz. Self-supervised transformers for unsupervised object discovery using normalized cut. In Conference on Computer Vision and Pattern Recognition, 2022. 1, 2, 3, 5, 6, 7, 9", + "[54] Zhongdao Wang, Liang Zheng, Yixuan Liu, and Shengjin Wang. Towards real-time multi-object tracking. The European Conference on Computer Vision (ECCV), 2020. 1", + "[55] Peter Welinder, Steve Branson, Takeshi Mita, Catherine Wah, Florian Schroff, Serge Belongie, and Pietro Perona. Caltech-ucsd birds 200. Technical Report CNS-TR-201, Caltech, 2010. 9", + "[56] Nicolai Wojke, Alex Bewley, and Dietrich Paulus. Simple online and realtime tracking with a deep association metric. In 2017 IEEE International Conference on Image Processing (ICIP), pages 3645-3649. IEEE, 2017. 1", + "[57] Danfei Xu, Yuke Zhu, Christopher Bongsoo Choy, and Li Fei-Fei. Scene graph generation by iterative message passing. 2017 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3097-3106, 2017. 1", + "[58] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable $\\{\\mathrm{detr}\\}$ : Deformable transformers for end-to-end object detection. In International Conference on Learning Representations, 2021. 5" + ], + "bbox": [ + 78, + 90, + 468, + 512 + ], + "page_idx": 11 + }, + { + "type": "page_number", + "text": "15834", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 11 + } +] \ No newline at end of file diff --git a/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/b6bef65d-9eb6-4535-9de8-7c08bf88dd4b_model.json b/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/b6bef65d-9eb6-4535-9de8-7c08bf88dd4b_model.json new file mode 100644 index 0000000000000000000000000000000000000000..ba15e4b93fbd70c2a6f8b271e798d80b14c51dd0 --- /dev/null +++ b/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/b6bef65d-9eb6-4535-9de8-7c08bf88dd4b_model.json @@ -0,0 +1,2600 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.11, + 0.13, + 0.862, + 0.177 + ], + "angle": 0, + "content": "MOST: Multiple Object localization with Self-supervised Transformers for object discovery" + }, + { + "type": "text", + "bbox": [ + 0.101, + 0.203, + 0.303, + 0.221 + ], + "angle": 0, + "content": "Sai Saketh Rambhatla1,3*" + }, + { + "type": "text", + "bbox": [ + 0.123, + 0.226, + 0.277, + 0.237 + ], + "angle": 0, + "content": "rssaketh@meta.com" + }, + { + "type": "text", + "bbox": [ + 0.35, + 0.204, + 0.452, + 0.221 + ], + "angle": 0, + "content": "Ishan Misra" + }, + { + "type": "text", + "bbox": [ + 0.335, + 0.226, + 0.47, + 0.238 + ], + "angle": 0, + "content": "imisra@meta.com" + }, + { + "type": "text", + "bbox": [ + 0.507, + 0.204, + 0.658, + 0.222 + ], + "angle": 0, + "content": "Rama Chellappa2,3" + }, + { + "type": "text", + "bbox": [ + 0.512, + 0.226, + 0.655, + 0.239 + ], + "angle": 0, + "content": "rchella4@jhu.edu" + }, + { + "type": "text", + "bbox": [ + 0.697, + 0.204, + 0.869, + 0.222 + ], + "angle": 0, + "content": "Abhinav Shrivastava3" + }, + { + "type": "text", + "bbox": [ + 0.702, + 0.226, + 0.864, + 0.238 + ], + "angle": 0, + "content": "abhinav@cs.umd.edu" + }, + { + "type": "text", + "bbox": [ + 0.183, + 0.246, + 0.788, + 0.266 + ], + "angle": 0, + "content": "\\(^{1}\\)Meta \\(^{2}\\)Johns Hopkins University \\(^{3}\\)University of Maryland, College Park" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.299, + 0.314, + 0.315 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.332, + 0.474, + 0.665 + ], + "angle": 0, + "content": "We tackle the challenging task of unsupervised object localization in this work. Recently, transformers trained with self-supervised learning have been shown to exhibit object localization properties without being trained for this task. In this work, we present Multiple Object localization with Self-supervised Transformers (MOST) that uses features of transformers trained using self-supervised learning to localize multiple objects in real world images. MOST analyzes the similarity maps of the features using box counting; a fractal analysis tool to identify tokens lying on foreground patches. The identified tokens are then clustered together, and tokens of each cluster are used to generate bounding boxes on foreground regions. Unlike recent state-of-the-art object localization methods, MOST can localize multiple objects per image and outperforms SOTA algorithms on several object localization and discovery benchmarks on PASCAL-VOC 07, 12 and COCO20k datasets. Additionally, we show that MOST can be used for self-supervised pretraining of object detectors, and yields consistent improvements on fully, semi-supervised object detection and unsupervised region proposal generation. Our project is publicly available at rssaketh.github.io/most." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.697, + 0.21, + 0.712 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.723, + 0.47, + 0.875 + ], + "angle": 0, + "content": "Object detectors are important components of several computer vision systems such as visual relationship detection [21, 29], human-object interaction detection [1, 13, 45, 52], scene graph generation [57] and object tracking [54, 56] etc. Performance of object detectors is heavily reliant on the availability of training data. However, annotating large object detection datasets can be expensive and time consuming [14, 27]. Additionally, the vocabulary of object detectors is limited by the training datasets and such detectors often fail to generalize to new cate" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.299, + 0.632, + 0.374 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.633, + 0.299, + 0.761, + 0.374 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.762, + 0.299, + 0.891, + 0.374 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.378, + 0.631, + 0.453 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.632, + 0.378, + 0.761, + 0.453 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.762, + 0.378, + 0.891, + 0.453 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.464, + 0.893, + 0.541 + ], + "angle": 0, + "content": "Figure 1: Top: Methods like LOST [41] (shown in figure), TokenCut [53] identify and localize the most salient foreground object and hence can detect only one object per image. Bottom: MOST is a simple, yet effective method that localizes multiple objects per image without training." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.553, + 0.895, + 0.903 + ], + "angle": 0, + "content": "gories [7]. This strategy is not scalable and a more effective approach is warranted. Object discovery is one such task that has the potential to address these concerns. Object discovery is the problem of identifying and grouping objects/parts in a large collection of images without human intervention [23, 24, 36, 43]. The first step in object discovery is to obtain region proposals and subsequently group them semantically. Previous works on discovery used Selective Search [46], randomized Prim's [30] or a region proposal network (RPN) [35] to get object proposals. [48-50] used inter-image similarity to construct a graph and performed optimization or ranking, to localize objects without any supervision. Such methods are computationally expensive and often fail to scale to datasets larger than 20000 images. [34] used region proposals from an RPN and proposed a never ending learning approach and is the first method shown to scale to \\(\\sim 100000\\) images. However, these region proposal methods are often of low quality, and therefore reduce the performance of discovery systems. Recently, LOST [41] and TokenCut [53] leveraged the object segmentation properties of transformers [47] trained using self-supervised learning (DINO [3]) to obtain high quality object proposals. They demonstrate significant improvements over" + }, + { + "type": "page_footnote", + "bbox": [ + 0.102, + 0.888, + 0.245, + 0.899 + ], + "angle": 0, + "content": "Work done while at UMD." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "15823" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.468, + 0.121 + ], + "angle": 0, + "content": "state-of-the-art on object discovery, salient object detection and weakly supervised object localization benchmarks." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.122, + 0.468, + 0.272 + ], + "angle": 0, + "content": "However, both LOST [41] and TokenCut [53] assume the presence of a single salient object per image and hence, can localize only one object as shown in Fig 1 (top). This assumption may hold for object centric datasets like ImageNet [37] but is not true for scene-centric real world datasets like PASCAL-VOC [12] and COCO [27]. In this work, we address the problem of localizing multiple objects per image and demonstrate the effectiveness of our approach for the task of unsupervised object localization and discovery on several standard benchmarks." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.273, + 0.47, + 0.771 + ], + "angle": 0, + "content": "We propose a new object localization method called \"Multiple Object localization with Self-supervised Transformers\" (MOST) which is capable of localizing multiple objects per image without using any labels. We use the features extracted from a transformer [47] network trained with DINO [3]. Our method is based on two empirical observations; 1) Patches within foreground objects have higher correlation with each other than the ones on the background [41] and 2) The similarity map computed using the features of a foreground object with all the features in the image is usually more localized and less noisier than the one computed using the feature of a background. Our algorithm analyzes the similarities between patches exhaustively using a fractal analysis tool called box counting [28]. This analysis picks a set of patches that most likely lie on foreground objects. Next, we perform clustering on the patch locations to group patches belonging to a foreground object together. Each of these clusters is called pools. A binary mask is then computed for each pool and a bounding box is extracted. This capability enables the algorithm to extract multiple bounding boxes per image as shown in Fig.1 (bottom). We demonstrate that without any training, our method can outperform state-of-the-art object localization methods that train class agnostic detectors to detect multiple objects. To prove the effectiveness of MOST, we demonstrate results on several object localization and discovery benchmarks. On self-supervised pre-training for object detectors, using MOST yields consistent improvement across multiple downstream tasks using \\(6 \\times\\) fewer boxes. When compared against other self-supervised transformer-based localization methods, MOST achieves higher recall with and without additional training. We summarize the contributions of our work below." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.785, + 0.468, + 0.829 + ], + "angle": 0, + "content": "- We propose MOST, an effective method to localize and discover multiple objects per image without supervision using transformers trained with DINO." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.841, + 0.468, + 0.899 + ], + "angle": 0, + "content": "- We perform exhaustive experiments to assess the performance of MOST on several localization and discovery benchmarks and show significant improvements over the baselines." + }, + { + "type": "list", + "bbox": [ + 0.097, + 0.785, + 0.468, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.166 + ], + "angle": 0, + "content": "The paper is organized as follows. In Section 2 we discuss related works on object localization and discovery. We describe our approach in detail in Section 3. We describe our experimental setup and present results in Section 4 and conclude in Section 5." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.181, + 0.65, + 0.198 + ], + "angle": 0, + "content": "2. Related Works" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.206, + 0.892, + 0.643 + ], + "angle": 0, + "content": "Unsupervised Object Localization and Discovery: Object category discovery can be broadly segregated into image-based [15, 16, 18-20, 42] and region-based methods [4, 8, 22-24, 34, 41, 48-50, 53]. Region-based methods start by generating object proposals and later group them into coherent semantic groups. Image-based approaches on the other hand, assume the localization task to be solved and focus solely on the semantic grouping. Our current method is closer to the former. Vo et al., [48-50] localize regions in images by constructing an inter-image similarity graph between regions and partitioning it using optimization or ranking. Due to the quadratic nature of the graph, these methods cannot scale to large datasets beyond tens of thousands of images. Our current work does not compute inter-image similarity between regions and scales linearly with number of images. Lee et al., [24] propose object graphs that incorporates knowledge about a few known categories to facilitate the discovery of novel categories. MOST doesn't assume any prior knowledge and has the ability to discover objects from scratch. Lee et al., [23] extend object graphs to a curriculum based discovery pipeline, that learns to discover easy objects first and progressively proceeds to discover the harder ones. Along similar lines, Rambhatla et al., [34] propose a large scale discovery pipeline, similar to [24] that leverages prior knowledge about a few categories. Authors of [34] use an RPN [35] trained on known categories as the localization method. In contrast to that, MOST localizes objects in images using features of a transformer [47] trained with DINO [3]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.645, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Object localization using self-supervised networks: Recently, CNNs [17] and Transformers [47] trained in a self-supervised fashion, have been shown to exhibit object localization/segmentation properties [3, 10]. This property is of particular interest as it has the potential to facilitate research on unsupervised localization, detection and segmentation. [41] is a simple method, based on the observation that the key features of the last self attention layer of a transformer, trained using DINO, has certain affinity. They construct a map of inverse degree to extract bounding boxes on objects in an unsupervised fashion. This method is shown to outperform recent state-of-the-art methods by a significant margin. [53] propose an alternate method for localizing objects using self-supervised transformers, based on normalized cut [39]. TokenCut [53] construct an undirected graph based on token feature similarities and use normalized cut to cluster foreground and background patches. SpectralCLUS" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "15824" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.08, + 0.095, + 0.47, + 0.155 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.164, + 0.471, + 0.226 + ], + "angle": 0, + "content": "Figure 2: Motivation for MOST: Example showing similarity maps of tokens within background and foreground for an image from the COCO dataset. Similarity maps of tokens within foreground patches are less random spatially." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.252, + 0.47, + 0.432 + ], + "angle": 0, + "content": "tering is used to solve the graph-cut and they show that the eigen vector corresponding to the second smallest eigenvalue provides a good cutting solution. TokenCut outperforms LOST on unsupervised object discovery. In addition to discovery, [53] also demonstrate impressive results on unsupervised saliency detection and weakly supervised object localization. Kyriazi et al., [31] propose deep spectral methods, that performs normalized cut [39] but using an affinity matrix computed using semantic and color features. Since this method is very similar to TokenCut and achieves lower performance, we only compare with the latter in this work." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.433, + 0.47, + 0.51 + ], + "angle": 0, + "content": "However, one limitation of LOST and TokenCut is that they can localize only one object per image. Our proposed method, MOST can automatically localize multiple objects per image and outperforms LOST and TokenCut on standard discovery benchmarks." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.524, + 0.255, + 0.541 + ], + "angle": 0, + "content": "3. Approach: MOST" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.549, + 0.47, + 0.656 + ], + "angle": 0, + "content": "MOST can be used to localize multiple objects in an image. Our approach, illustrated in Fig. 3, first identifies a set of tokens that is computed from patches on foreground objects. These tokens are then clustered and each cluster, named pool, is used to obtain a bounding box. Next, we discuss a few preliminaries in Section 3.1 followed by the motivation and proposed solution in Section 3.2." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.666, + 0.218, + 0.68 + ], + "angle": 0, + "content": "3.1. Preliminaries" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.689, + 0.469, + 0.763 + ], + "angle": 0, + "content": "Box Counting: Box counting is a method of analyzing a pattern by breaking and analyzing it at smaller scales. This is done by performing a raster scan of the pattern at different scales and computing appropriate metrics to assess its fractal nature. In this work, we use a sliding window scan." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Vision Transformers: ViTs [9] operate on learned embeddings, called tokens, generated from non-overlapping image patches of resolution \\( \\mathrm{P} \\times \\mathrm{P} \\) (typically \\( \\mathrm{P} = 8 / 16 \\)) that form a sequence. To be precise, an image \\( \\mathrm{I} \\) of shape \\( H \\times W \\times 3 \\) is first divided into non-overlapping patches of resolution \\( P \\times P \\times 3 \\), generating a total of \\( \\mathrm{N} = HW / P^2 \\) patches. Next, each patch is embedded via a trainable linear layer to generate a token of dimension \\( d \\) to form a sequence of patches. An extra [CLS] token [6] is added to this sequence, whose" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.136 + ], + "angle": 0, + "content": "purpose is to aggregate the information from the tokens of the sequence. Typically, a projection head is attached to the [CLS] to train the network for classification." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.137, + 0.893, + 0.456 + ], + "angle": 0, + "content": "DINO: DINO [3] combines self-training and knowledge distillation without labels for self supervised learning. DINO constructs two global views and several local views of lower resolution, from an image. DINO consists of a teacher and a student network. The student processes all the crops while the teacher is operated only on the global crops. The teacher network then distills its dark knowledge to the student. This encourages the student network to learn local to global correspondences. In contrast to other knowledge distillation methods, DINO's teacher network is updated dynamically during training using exponential moving average. DINO was shown to perform on par or better than several baselines on several tasks of image retrieval, copy detection, instance segmentation etc. The property of importance to the current work, is the ability of DINO to localize foreground regions of semantic entities in an image. [41, 53] leverage this property to localize the salient object in an image by using the key features from the last self-attention layer. Similar to [41, 53], we concatenate the key features of all the heads in the last self-attention layer to obtain the input to MOST." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.467, + 0.747, + 0.483 + ], + "angle": 0, + "content": "3.2. Multiple object localization" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.491, + 0.892, + 0.701 + ], + "angle": 0, + "content": "Motivation: Consider the example shown in Fig. 2. We show three examples of the similarity maps of a token (shown in red) picked on the background (column 2) and foreground (columns 3, 4). Tokens within foreground patches have higher correlation than the ones on background [41]. This results in the similarity maps of foreground patches being less \"spatially\" random than the ones on the background. The task then becomes to analyze the similarity maps and identify the ones with less spatial randomness. Box counting [25, 33] is a popular technique in fractal analysis that analyzes spatial patterns at different scales to extract desired properties. Hence, we adopt box counting for our case and since, we are interested in randomness, we adopt entropy as the metric." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.703, + 0.893, + 0.901 + ], + "angle": 0, + "content": "Preprocessing: The input to our method is a \\(d\\)-dimensional feature \\(F \\in \\mathbb{R}^{N \\times d}\\), extracted from an image using a neural network. Here, \\(N\\) denotes the number of spatial locations in the feature map, in case of a CNN, or number of tokens, in case of a transformer network. The aim is to identify subsets of tokens, which we call pools, that can be used to localize all the objects in an image. We do not make any assumption on the number of objects present in the image. Given the feature \\(F\\), we compute an outer product matrix \\(A = F F^T \\in \\mathbb{R}^{N \\times N}\\). Row \\(i\\) of matrix \\(A\\), i.e., \\(A[i,:]\\) encodes a similarity map of a token at location \\(i\\) with all the other tokens in \\(F\\). Next, each row of \\(A\\) is processed by the Entropy-based Box Analysis (EBA) module." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "15825" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.093, + 0.895, + 0.38 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.075, + 0.393, + 0.893, + 0.456 + ], + "angle": 0, + "content": "Figure 3: Overview of MOST: MOST operates on features extracted from transformers trained using DINO. The features are used to compute the outer product \\( A \\). Each row of \\( A \\) is analyzed by the entropy-based box analysis (EBA) module that identifies tokens extracted from foreground patches. These patches are clustered using spatial locations as features to form pools. Each pool is then post-processed to generate a bounding box." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.481, + 0.473, + 0.879 + ], + "angle": 0, + "content": "Entropy-based Box Analysis (EBA): The proposed entropy based box analysis module performs a fractal analysis method, called box counting to segregate similarity maps of tokens on foreground patches from those of background. As shown in Fig. 3, we perform a raster scan with increasing box (used interchangeably with kernel in this work) sizes on each map. Traditionally, measures like lacunarity [44] are computed within each box to analyze the pattern. In this work, we average the elements within each box. This can be implemented efficiently using pooling operations. The resulting downsampled map is flattened and the entropy is computed using the pmf computed as follows: \\( p(x = x_{i}) = \\sum_{i = 1}^{h.w}\\frac{\\mathbb{1}(f_{i} == x_{i})}{h.w} \\), where \\( f_{i} \\) is the \\( i^{\\text{th}} \\) index in the feature map. A downsampled map belongs to a token on a foreground patch if its entropy is less than a threshold \\( \\tau \\). Using \\( K \\) boxes in the EBA module results in \\( K \\) entropy values \\( e_k(k\\in \\{1,2,\\dots ,K\\}) \\). Finally, we perform a majority voting among the entropies of all the downsampled maps, i.e., \\( \\sum_{i = 1}^{K}\\frac{\\mathbb{1}(e_i\\leq\\tau)}{K} >0.5 \\), to decide if the original similarity map belongs to a token on a foreground patch. A map of dimension \\( n\\times n \\) has a maximum entropy of \\( log(n^{2}) \\). We use a threshold of the form \\( \\tau = a + blog(n^{2}) \\) (we use \\( a = 1,b = 0.5 \\) in this work). We do not consider \\( \\tau \\) as a hyperparameter and we pick a value that is mid-way between the minimum and maximum permissible value \\( (b = 0.5) \\). To prevent a threshold of 0 for \\( n = 1 \\), we add a constant \\( (a = 1) \\)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.885, + 0.47, + 0.904 + ], + "angle": 0, + "content": "Clustering: The EBA module, identifies a set \\( S = \\{p|p\\in \\)" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.481, + 0.892, + 0.678 + ], + "angle": 0, + "content": "\\(\\{1,2,\\dots ,N\\}\\}\\), that contains the spatial locations of tokens computed from foreground patches. Often, highly redundant neighboring tokens are identified. We group neighboring tokens with the help of a clustering step to obtain pools. We convert the linear index \\(p\\) of the tokens to cartesian coordinates \\((x,y)\\), and use that as the feature for clustering. Manhattan distance is used as the dissimilarity metric with a threshold \\(\\epsilon\\) (\\(\\epsilon = 2\\) i.e. Moore neighborhood). Since, the number of pools is not known a-priori, we use a density-based clustering method, DBSCAN [11] which automatically identifies the number of clusters from the data. Pools identified by the clustering step are then post-processed to obtain bounding boxes on foreground objects." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.678, + 0.893, + 0.829 + ], + "angle": 0, + "content": "Post-processing: The clusters, called pools, obtained from the clustering step are then post-processed to obtain one box per pool. Consider \\( M \\) pools identified by the clustering step, i.e. \\( \\mathcal{C}_i \\), where \\( i \\in \\{1,2,\\dots M\\} \\). Each pool \\( \\mathcal{C}_i \\) is a set of token locations \\( \\mathcal{C}_i = \\{p^i | p^i \\in \\{1,2,\\dots ,N\\}\\} \\). We leverage the first observation mentioned above to obtain a bounding box from the pool as follows. First, we build a binary similarity matrix \\( \\hat{A} = A > 0 \\). Next, within the tokens in the pool, we identify the one with lowest degree in \\( \\hat{A} \\), called the core token, \\( c^* \\)." + }, + { + "type": "equation", + "bbox": [ + 0.549, + 0.836, + 0.842, + 0.879 + ], + "angle": 0, + "content": "\\[\nc ^ {*} = \\underset {c \\in \\mathcal {C} _ {i}} {\\arg \\min } d _ {c} \\quad \\text {w h e r e} \\quad d _ {c} = \\sum_ {j = 1} ^ {N} \\hat {A} [ c, j ]\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.886, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Authors of LOST [41] report that tokens with low degrees" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "15826" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.089, + 0.895, + 0.152 + ], + "angle": 0, + "content": "Table 1: Results on unsupervised pre-training of object detectors. We train object detectors in a self-supervised fashion on the COCO dataset using different localization methods and compare their performance on the downstream tasks of semi and fully supervised object detection. COCO train set is used for fine-tuning and \\( k\\% \\) refers to the number of labeled samples used for training. Results are reported using AP[0.50:0.95] (denoted as AP), \\( {\\mathrm{{AP}}}_{0.50} \\) ,and \\( {\\mathrm{{AP}}}_{0.75} \\) on COCO validation set." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.161, + 0.894, + 0.34 + ], + "angle": 0, + "content": "
MethodBoxes per imageVOC 07+12COCO
k=10%fully supervisedk=1%k=2%k=5%fully supervised
APAP50AP75APAP50AP75APAPAP50
LOST [41]140.8860.3144.3663.5883.2770.4812.83 ± 0.3217.23 ± 0.3023.43 ± 0.3844.3062.80
TCut [53]141.1460.5944.3563.7983.5670.7013.13 ± 0.3817.27 ± 0.2123.27 ± 0.2343.8062.30
539.1257.5142.2963.4483.1470.3513.57 ± 0.3817.87 ± 0.3223.17 ± 0.4044.3062.80
SS [46]1040.7660.0044.4664.2383.4471.5513.73 ± 0.2918.00 ± 0.2622.83 ± 0.2543.9062.60
1542.1461.4145.8664.2483.7471.4113.87 ± 0.2918.23 ± 0.4023.13 ± 0.1144.3062.60
MOST4.6543.0363.2946.6164.3484.1271.7713.93 ± 0.3818.13 ± 0.2522.63 ± 0.1144.8063.50
SS3042.1261.2045.7164.8483.9871.7614.47 ± 0.3518.23 ± 0.4223.57 ± 0.2144.0062.30
MOST13.0944.4063.8348.2865.2484.2472.3714.83 ± 0.2118.30 ± 0.1723.43 ± 0.4545.2064.00
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.365, + 0.473, + 0.593 + ], + "angle": 0, + "content": "most likely fall within an object. Next, we remove the tokens from the pool that do not correlate positively with \\( c^* \\) to form a reduced pool \\( \\mathcal{C}_i^* \\). This ensures that all the tokens in the current pool lie on the same foreground object. Next, a binary mask is constructed by computing the sum of similarities of token features in \\( \\mathcal{C}_i^* \\) with the features of all the tokens, i.e. \\( m_k^i = 11(\\sum_{c\\in \\mathcal{C}_i^*}f_k^T f_c\\geq 0) \\). Finally, connected component analysis is performed on the binary mask and the bounding box of the island that contains \\( c^* \\) is selected as the region containing the object. We repeat this process for all the \\( M \\) pools to generate \\( M \\) bounding boxes per image. Note that, \\( M \\) is not assumed to be known a-priori and is decided automatically by our method. Additionally, we remove trivial boxes i.e., boxes which have area less than than a threshold (256) or cover the whole image." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.593, + 0.473, + 0.669 + ], + "angle": 0, + "content": "Implementation Details: For all our experiments, we use the ViT-S/16 and ViT-B/8 [9] models trained with DINO [3] to extract the features. We concatenate the key features of all the heads from the last self-attention layer to use as the input to our method." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.679, + 0.21, + 0.697 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.705, + 0.47, + 0.826 + ], + "angle": 0, + "content": "In this section we describe, in detail, the experimental setup used for evaluation. We evaluate our method on two setups, namely the localization setup, and the discovery setup. We begin by describing the datasets and metrics in Sec. 4.1. We describe the evaluation setups in Sec. 4.2. Sec. 4.3 compares our method against contemporary work. We then describe ablation experiments in Sec. 4.4 and show qualitative results in Sec. 4.6." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.833, + 0.277, + 0.848 + ], + "angle": 0, + "content": "4.1. Datasets and Metrics" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.471, + 0.903 + ], + "angle": 0, + "content": "We use the PASCAL-VOC [12] (2007, 2012 splits) and the COCO [27] (COCO20k [49] and COCO splits) datasets in our experiments. The PASCAL VOC [12] 2007 and 2012" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.365, + 0.892, + 0.47 + ], + "angle": 0, + "content": "trainval sets consists of 5011, 11540 images respectively, spanning twenty objects. The PASCAL VOC [12] test set consists of 4952 images. The COCO [27] 2014 train set consists of \\(\\sim 110\\mathrm{k}\\) images containing over eighty objects and the COCO minimal set consists of 5000 images. We do not use any class or bounding box annotations for our method except for evaluation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.471, + 0.893, + 0.639 + ], + "angle": 0, + "content": "For the localization setup, we use the average precision at different thresholds ([0.5:0.95], 0.5 and 0.75), average recall (AR1, AR10 and AR100) and Correct Localization (CorLoc) metrics for evaluation. CorLoc is defined as the fraction of the images in which atleast one object is localized with an IoU greater than a threshold (0.5 in this work). AP, AR are defined in the usual way. For the object discovery setup, we report both the PASCAL VOC style \\(\\mathrm{AP}_{50}\\) and COCO style \\(\\mathrm{AP}_{[50:95]}\\) metrics along with area under the purity-coverage plots [8, 34]. We refer the interested readers to [34] for definitions of purity and coverage." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.651, + 0.589, + 0.667 + ], + "angle": 0, + "content": "4.2. Setups" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.675, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Localization setup: This setup evaluates the localization performance of methods. We evaluate models on a) unsupervised pre-training, b) Multiple Object Localization, and c) single object localization. For unsupervised pre-training, localization methods are used to train object detectors in an unsupervised fashion and their performance is evaluated on the downstream task of object detection. In this work, we use the recently proposed DETReg [2] as the pre-training strategy which uses a Deformable DeTR [58] architecture. DETReg uses an object localization method and pre-trains an object detector in an unsupervised fashion. We evaluate the pre-trained model on the downstream tasks of semi-supervised, fully-supervised and class-agnostic object proposal generation. In the semi-supervised setting, models are trained on the PASCAL-VOC(07+12) and COCO train" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "15827" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.089, + 0.327, + 0.166 + ], + "angle": 0, + "content": "Table 2: Unsupervised class agnostic region proposal evaluation on COCO validation set: We compare the performance of region proposals for training DETReg. \\(Rk\\) is Recall@k" + }, + { + "type": "table", + "bbox": [ + 0.08, + 0.177, + 0.325, + 0.29 + ], + "angle": 0, + "content": "
MethodBoxes per imageAP\\( AP_{50} \\)\\( AP_{75} \\)R1R10R100
LOST [41]10.10.500.41.43.9
TCut [53]10.310.10.61.94.6
50.10.400.114.2
SS [46]100.10.300.11.14.4
150.10.300.114.1
300.10.300.114
MOST4.650.81.410.61.94.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.336, + 0.089, + 0.659, + 0.165 + ], + "angle": 0, + "content": "Table 3: Results on object discovery: Comparison of MOST with recent works on unsupervised object discovery. We experiment with three cluster numbers, i.e., 20, 30, 40, on VOC 2007, 2007+12 and 80, 90, 100 on COCO20k." + }, + { + "type": "table", + "bbox": [ + 0.339, + 0.177, + 0.656, + 0.29 + ], + "angle": 0, + "content": "
Metric Train →VOC 2007VOC 07+12COCO20k
Clusters →2030402030408090100
APLOST [41]9.159.6410.1110.9512.1412.972.662.912.86
MOST9.2010.0711.0910.1212.8913.303.133.183.32
AP50LOST [41]26.3227.7829.4629.3533.2734.807.177.727.87
MOST25.3528.1931.3127.0434.4034.548.138.148.76
" + }, + { + "type": "table_caption", + "bbox": [ + 0.668, + 0.09, + 0.902, + 0.166 + ], + "angle": 0, + "content": "Table 4: Results on single-object localization: Comparison of MOST with recent object discovery methods on VOC 07, 12 and COCO20k using CorLoc." + }, + { + "type": "table", + "bbox": [ + 0.671, + 0.177, + 0.899, + 0.29 + ], + "angle": 0, + "content": "
MethodVOC 07VOC 12COCO20k
rOSD [49]54.555.348.5
LOD [50]53.655.148.5
DINO-seg† [3]45.846.242.1
LOST [41]61.964.050.7
TokenCut [53]68.872.158.8
LOST [41] + CAD65.770.457.5
TCut [53]+CAD71.475.362.6
MOST74.877.467.1
" + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.315, + 0.47, + 0.42 + ], + "angle": 0, + "content": "sets without labels and are fine-tuned on \\( k\\% \\) of labeled data similar to [2]. In the fully supervised setting, pre-trained models are fine-tuned on the full PASCAL-VOC and COCO dataset using all the labels. For the class-agnostic object proposal generation, models are pre-trained on COCO dataset without labels and the generated object proposals are evaluated on the COCO validation set similar to [2]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.421, + 0.47, + 0.496 + ], + "angle": 0, + "content": "We follow the settings used in [50] for multiple-object localization and evaluate on PASCAL-VOC 2007 and COCO20k. For single-object localization, we follow the settings in [41, 53] and evaluate on PASCAL-VOC 2007, PASCAL-VOC 2012 and COCO20k." + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.497, + 0.471, + 0.648 + ], + "angle": 0, + "content": "Discovery setup: This setup evaluates the object discovery performance. Similar to [41] we use the regions obtained by our localization method, to perform K-means clustering and use the resulting cluster labels to train Faster-RCNN object detectors on PASCAL-VOC 2007, 2012 trainval and COCO20k train sets. We report results of these experiments on the PASCAL-VOC 2007 test and COCO minival sets respectively. In addition to this, we report the performance of our discovery method on COCO train set, similar to the large scale discovery in [34]." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.655, + 0.431, + 0.672 + ], + "angle": 0, + "content": "4.3. Comparison with contemporary methods" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.679, + 0.47, + 0.71 + ], + "angle": 0, + "content": "In this section we compare our method against contemporary works the localization and discovery setups." + }, + { + "type": "title", + "bbox": [ + 0.076, + 0.726, + 0.26, + 0.743 + ], + "angle": 0, + "content": "4.3.1 Localization setup" + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.75, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Unsupervised Pre-training: Table 1 compares the results of all the localization methods on unsupervised pre-training of object detectors. We use average precision at different IoU thresholds ([0.50:0.95]: AP, 0.5: \\(\\mathrm{AP}_{0.50}\\), 0.75: \\(\\mathrm{AP}_{0.75}\\)) for evaluation. On the semi-supervised setting, on VOC \\(07 + 12\\) (\\(k = 10\\%\\)), the self-supervised transformer based methods (LOST, TokenCut and MOST) outperform SS [46] with fewer boxes per image. In particular, TokenCut (denoted as TCut in Table 1) which outputs only one box per image, outperforms SS, using ten boxes per image, by \\(\\sim 0.4\\)" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.315, + 0.895, + 0.573 + ], + "angle": 0, + "content": "points on mAP. MOST which outputs an average of 4.65 boxes per image outperforms TokenCut (the best performing self-supervised transformer based method) by 1.89, 2.7 and 2.26 percentage points on AP, \\(\\mathrm{AP}_{50}\\), and \\(\\mathrm{AP}_{75}\\) respectively. This can be attributed to the ability of MOST to output multiple foreground regions resulting in more samples for pre-training which is not possible in the case of TokenCut. MOST outperforms SS, that outputs 30 boxes per image, by 0.91, 2.09 and 0.9 points on AP, \\(\\mathrm{AP}_{50}\\), and \\(\\mathrm{AP}_{75}\\) respectively using almost \\(6\\times\\) fewer boxes per image and this can be attributed to the ability of MOST to generate high quality proposals. On COCO, MOST outperforms TokenCut by 0.8 and 0.86 on the \\(1\\%\\) and \\(2\\%\\) setting of semi-supervised learning. MOST with a ViT-B/8 backbone, that outputs 13.09 boxes on average per image, outperforms SS (with 30 boxes per image) by 0.36, 0.07 points on \\(k = 1\\%\\) and \\(k = 2\\%\\) few shot splits of COCO respectively." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.578, + 0.895, + 0.701 + ], + "angle": 0, + "content": "On the fully supervised setting, MOST outperforms LOST and TokenCut by 0.76 and 0.55 (AP) percentage points respectively on VOC 07+12. On COCO, MOST outperforms them by 0.50 and 1 points respectively. On VOC 07+12, MOST using ViT-B/8 (13.09 boxes per image) outperforms SS (with 30 boxes per image) by 0.40. On the much harder COCO dataset, MOST outperforms SS 1.20 (AP) percentage points using \\(2 \\times\\) fewer boxes per image." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.897, + 0.902 + ], + "angle": 0, + "content": "In Table 2 we report the class agnostic object proposal evaluation of DETReg trained using different localization methods. We report average precision at different IoU thresholds (AP, \\(\\mathrm{AP}_{50}\\), \\(\\mathrm{AP}_{75}\\)) and recall @ 1, 10 and 100 proposals per image (denoted as R1, R10, and R100) to evaluate the quality of region proposals. Note that the numbers in the table are low because of the unsupervised nature of training. All the self-supervised transformer-based methods achieve performance better than SS with far fewer boxes. In recall, TokenCut and MOST perform on par with each other and outperform rest of the methods with significant improvements. MOST achieves the highest performance on average precision among all the methods. It can achieve" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "15828" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.089, + 0.214, + 0.153 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.138, + 0.156, + 0.155, + 0.164 + ], + "angle": 0, + "content": "k=1" + }, + { + "type": "image", + "bbox": [ + 0.217, + 0.089, + 0.351, + 0.154 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.273, + 0.156, + 0.292, + 0.164 + ], + "angle": 0, + "content": "k=3" + }, + { + "type": "image", + "bbox": [ + 0.352, + 0.089, + 0.487, + 0.154 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.409, + 0.156, + 0.428, + 0.164 + ], + "angle": 0, + "content": "k=5" + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.17, + 0.214, + 0.243 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.137, + 0.243, + 0.157, + 0.252 + ], + "angle": 0, + "content": "k=1" + }, + { + "type": "image", + "bbox": [ + 0.217, + 0.17, + 0.351, + 0.243 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.273, + 0.243, + 0.294, + 0.252 + ], + "angle": 0, + "content": "k=2" + }, + { + "type": "image", + "bbox": [ + 0.352, + 0.17, + 0.487, + 0.243 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.408, + 0.243, + 0.429, + 0.252 + ], + "angle": 0, + "content": "k=3" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.269, + 0.489, + 0.331 + ], + "angle": 0, + "content": "Figure 4: Effect of kernel size: Different kernel sizes can identify different tokens as belonging to the foreground. Multiple kernels help eliminate noisy predictions (first triplet) and missed predictions (second triplet)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.357, + 0.469, + 0.432 + ], + "angle": 0, + "content": "higher precision and recall because of its ability to output multiple high quality regions per image. While LOST and TokenCut output high quality boxes, they cannot output more than one box per image. SS on the other hand, outputs multiple boxes but with poor quality." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.433, + 0.469, + 0.569 + ], + "angle": 0, + "content": "Multiple Object Localization: We compare with LOD, the state-of-the-art method on the multi-object localization benchmark proposed by LOST using the code released by authors. On VOC2007, we attain an odAP[0.5:0.95] of 6.43 compared to 5.35 attained by LOD, an improvement of 1.09 percentage points. On the COCO20k dataset, we attain a performance of 1.70 (compared to 1.53 achieved by LOD) on the harder odAP[0.50:0.95] metric. Note, we do not compare with rOSD [49] as LOD [50] outperforms it." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.569, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Single Object Localization: Table 4 compares the results of our method on single object localization with recent methods on PASCAL VOC 2007, 2012 and COCO20k respectively. We use the CorLoc metric to evaluate methods. Note that MOST is a multiple object localization method and this setup evaluates the ability of methods to output a single region. Since MOST outputs multiple boxes, we use the heuristic, average best overlap (for evaluating object proposals in [46]), to select one region per image. The numbers reported for MOST in this table are the \"best\" case scenario. We outperform LOST by 12.9, 13.4 and 16.4 percentage points on VOC 2007, 2012 and COCO20k respectively. We outperform TokenCut [53] by 6, 5.3 and 8.3 percentage points on the three datasets respectively. To obtain multiple regions per image, authors of LOST train a foreground object detector using the regions obtained by their method as supervision, called LOST+CAD [41]. This method can output multiple boxes per image and from Table 4, even without any training, our method outperforms LOST+CAD and TokenCut+CAD by 9.1, 7, 9.6 and 3.4, 2.1, 4.5 percentage points on VOC 2007, 2012 and COCO20k respectively." + }, + { + "type": "image", + "bbox": [ + 0.5, + 0.089, + 0.702, + 0.173 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.706, + 0.089, + 0.908, + 0.173 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.5, + 0.175, + 0.702, + 0.259 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.706, + 0.175, + 0.908, + 0.259 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.497, + 0.269, + 0.91, + 0.331 + ], + "angle": 0, + "content": "Figure 5: Figure demonstrating the effect of clustering in MOST: Each image consists of a bounding box generated from a pool. We observe that each pool focuses on different foreground instance." + }, + { + "type": "image", + "bbox": [ + 0.502, + 0.354, + 0.6, + 0.41 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.601, + 0.354, + 0.696, + 0.41 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.698, + 0.354, + 0.794, + 0.41 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.795, + 0.354, + 0.892, + 0.41 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.421, + 0.892, + 0.453 + ], + "angle": 0, + "content": "Figure 6: Figure demonstrating the effect of clustering in MOST. Eliminating the clustering results in noisier outputs." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.489, + 0.892, + 0.7 + ], + "angle": 0, + "content": "Discovery Setup: This setup evaluates the true object discovery performance as the localized boxes are used to discover semantic groups. Following LOST [41], we first cluster the features of the localized objects using K-means clustering. For VOC 2007 and \\(2007 + 2012\\) trainval splits, we use 20, 30 and 40 clusters. We use 80, 90 and 100 clusters for COCO20k train split. We report the results of experiments on VOC 2007, \\(07 + 12\\) trainval sets on VOC 2007 test set. For experiments on COCO20k, we report results on the COCO validation set. Results are tabulated in Table 3. MOST outperforms LOST in most settings with the margin of improvement higher for more number of clusters and more cluttered datasets like COCO. For more details on clustering and training refer to supplementary." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.893, + 0.901 + ], + "angle": 0, + "content": "Finally, we evaluate the performance of MOST on large-scale object discovery setup introduced in [34]. For this setup, we use the area under the purity coverage plot as the metric. [34] automatically identifies the number of clusters and obtains an AuC@0.5 of \\(3.6\\%\\) on the COCO 2014 train set. We extract the DINO [CLS] token features of regions obtained from MOST for K-Means clustering. To avoid specifying the number of clusters manually, we employ the \"kneedle\" method [38] to get the optimal number of clusters (more details in supplementary). Next, we randomly sample 10000 features from the whole dataset and cluster them using K-means with the optimal number of clusters. This subsampling avoids loading all the features into mem" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "15829" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.092, + 0.465, + 0.224 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.237, + 0.472, + 0.314 + ], + "angle": 0, + "content": "Figure 7: Recall analysis: Comparison of recall values of MOST, MOST+CAD with LOST and LOST+CAD. LOST generates one bounding box per image. MOST+CAD, MOST have higher recall and cover more ground-truth objects for a fixed set of boxes." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.34, + 0.47, + 0.446 + ], + "angle": 0, + "content": "ory. MOST + optimal K-means achieves an AuC@0.5 of \\(8.74\\%\\) on COCO 2014 train set. We use the cluster labels to train an object detector on the COCO train set and achieve an \\(\\mathrm{AP / AP}_{50}\\) of \\(3.9 / 9.5\\%\\) compared to \\(5.2\\%\\) \\(\\mathrm{AP}_{50}\\) obtained by [34] on COCO validation set. For more experiments on unsupervised saliency detection and weakly supervised localization, refer to the supplementary." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.455, + 0.283, + 0.47 + ], + "angle": 0, + "content": "4.4. Ablation Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.478, + 0.47, + 0.689 + ], + "angle": 0, + "content": "Effect of kernel size: The EBA module performs box analysis in a sliding window fashion using boxes (or kernels) of different sizes. We implement this efficiently using a pooling operation. We visualize the effect of the size of pooling kernels on the final output in Fig. 4. We observe that the majority voting performed in EBA, helps in removing noisy predictions in the first triplet, where a box identified by kernel of size 1 is eliminated by majority voting of kernels with larger receptive field. In the second triplet in Fig. 4, an object which was missed by the lower order kernels \\((\\mathrm{k} = [1,4])\\), can be picked up with a higher order kernel \\((\\mathrm{k} = 5)\\). For all our experiments, we use kernels of sizes upto 5 (i.e. \\(\\mathrm{k} = [1,5]\\)). For quantitative results on the effect of kernel sizes, refer to the supplementary." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.689, + 0.469, + 0.78 + ], + "angle": 0, + "content": "Effect of clustering: MOST performs clustering with the token locations as features to obtain pools. Each pool contains tokens belonging to a foreground object. We show the effect of clustering qualitatively in Fig. 5. We observe that each pool focuses on one foreground object and illustrate the bounding boxes extracted from each pool." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.469, + 0.886 + ], + "angle": 0, + "content": "Each pool contains tokens belonging to a foreground object. We show the effect of forming pools qualitatively in Fig. 6. The first image in each pair shows the output of MOST without clustering to form pools and the second image shows the output with the formation. We observe that, without clustering, each token can generate a bounding box resulting in noisier outputs." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.886, + 0.469, + 0.902 + ], + "angle": 0, + "content": "Recall of boxes: To analyze the object localization perfor" + }, + { + "type": "table_caption", + "bbox": [ + 0.508, + 0.09, + 0.882, + 0.105 + ], + "angle": 0, + "content": "Table 5: Effect of backbone on single-object localization" + }, + { + "type": "table", + "bbox": [ + 0.565, + 0.116, + 0.83, + 0.205 + ], + "angle": 0, + "content": "
BackboneVOC 2007VOC 2012COCO20k
ViT-S/884.2586.0080.50
ViT-S/1674.8077.4068.60
ViT-B/885.4087.0081.73
ViT-B/1672.7276.2867.20
" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.232, + 0.892, + 0.488 + ], + "angle": 0, + "content": "mance of MOST, we compare its recall with LOST and TokenCut on VOC 07, 12 and COCO20k datasets in Fig. 7. The x-axis represents the maximum number of boxes allowed per image and the y axis plots the recall. LOST and TokenCut generate only one box per image and hence have fixed recall in all the plots. MOST can generate more boxes and hence have higher recall than LOST and TokenCut. [41] trains a class agnostic detector (CAD) to output multiple boxes per image using the output of LOST as supervision. Without a single step of training, MOST performs competitively against LOST+CAD on all the datasets. With a class agnostic detector, MOST+CAD outperforms LOST, TokenCut and their CAD counterparts comfortably on all the datasets. On COCO20k, a much harder dataset, MOST+CAD outperforms all the methods with a significant margin demonstrating its superior localization abilities." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.49, + 0.892, + 0.642 + ], + "angle": 0, + "content": "Effect of EBA: We study the effect of EBA on single-object localization. The task of the EBA module is to identify tokens on foreground instances from similarity maps. We replace the EBA module with the strategy used by LOST [41], effectively giving LOST the ability to localize multiple objects. We use top-100 patches and this system achieves a CorLoc of 63.66 (compared to 74.84 of MOST). The EBA module can automatically pick the right tokens, unlike LOST to localize multiple objects. This experiment demonstrates the benefit of the proposed EBA module." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.643, + 0.892, + 0.838 + ], + "angle": 0, + "content": "Timing analysis: MOST can localize multiple objects per image and does so by analyzing the similarity maps of all the tokens which is computationally more expensive. To understand this requirement, we perform a timing analysis. On average, LOST takes 0.008s per image while MOST takes 0.3s. MOST obtains a recall of 0.19, 0.21, and 0.08 on VOC07, VOC12, and COCO20k respectively (compared to 0.13, 0.15, and 0.03 of LOST). This translates to localizing an additional 750, 2400, and 7200 instances than LOST on VOC07, VOC12, and COCO20k respectively. We believe the additional time taken by MOST is justified by the improvement in recall performance which is essential for an object localization method." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Effect of backbone: We study the effect of backbone on MOST in Table 5. We observe that backbones with a smaller patch size can localize more objects, especially smaller ones (refer to supplementary for qualitative results)" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "15830" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.085, + 0.089, + 0.216, + 0.159 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.218, + 0.089, + 0.342, + 0.159 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.343, + 0.089, + 0.483, + 0.159 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.484, + 0.089, + 0.55, + 0.159 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.552, + 0.089, + 0.679, + 0.159 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.68, + 0.089, + 0.752, + 0.159 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.753, + 0.089, + 0.885, + 0.159 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.085, + 0.161, + 0.218, + 0.231 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.221, + 0.161, + 0.35, + 0.231 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.352, + 0.161, + 0.483, + 0.23 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.485, + 0.161, + 0.617, + 0.23 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.619, + 0.161, + 0.751, + 0.23 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.753, + 0.161, + 0.885, + 0.231 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.238, + 0.236, + 0.333, + 0.249 + ], + "angle": 0, + "content": "(a) VOC 07+12" + }, + { + "type": "image_caption", + "bbox": [ + 0.654, + 0.236, + 0.718, + 0.249 + ], + "angle": 0, + "content": "(b) COCO" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.262, + 0.892, + 0.308 + ], + "angle": 0, + "content": "Figure 8: Qualitative results of MOST on VOC 07, 12 and COCO: MOST can localize multiple objects in cluttered scenes without training. Localization ability of MOST is not limited by the biases of annotators and can localize rocks, mountains, branches, water bodies, etc." + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.314, + 0.471, + 0.405 + ], + "angle": 0, + "content": "Table 6: Results on unsupervised saliency detection: We compare MOST to state-of-the-art unsupervised saliency detections methods. Top results are in bold and second best is highlighted in blue. Ability to detect multiple objects in images is a good tradeoff for a slight drop in performance on saliency detection" + }, + { + "type": "table", + "bbox": [ + 0.08, + 0.417, + 0.469, + 0.55 + ], + "angle": 0, + "content": "
MethodECSSDDUTSDUT-OMRON
max Fβ IoU Acc (%)max Fβ IoU Acc (%)max Fβ IoU Acc (%)
DeepUSPS[32]58.444.079.542.530.577.341.430.577.9
BigBiGAN [51]78.267.289.960.849.887.854.945.385.6
E-BigBiGAN [51]79.768.490.662.451.188.256.346.486.0
LOST [41]75.762.588.061.852.087.147.440.279.6
TCut [53]80.371.291.867.257.690.360.053.388.0
MOST79.163.189.066.653.889.757.047.587.0
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.559, + 0.47, + 0.62 + ], + "angle": 0, + "content": "resulting in a higher CorLoc. This comes at a cost of producing noisier outputs. We refer interested readers to the supplementary for more analysis and qualitative results on the effect of backbones and patch sizes." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.634, + 0.299, + 0.65 + ], + "angle": 0, + "content": "4.5. Additional Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.659, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Unsupervised Saliency Detection: MOST can easily be extended to unsupervised saliency detection. We experiment with ECSSD [40], DUTS [26] and DUT-OMRON [5] datasets and use the metrics used by [41, 53] for evaluation. All these datasets require methods to segment the salient object in an image. Hence, naively using MOST doesn't perform well. To extend MOST for saliency detection, we select the largest pool and use the similarity map computed using its tokens as the saliency map. In Table 6, we compare MOST with TokenCut and LOST on the three datasets. MOST outperforms LOST comfortably on all the metrics, datasets and fares competitively against TokenCut. We believe that the ability to detect multiple objects in images is a good tradeoff for a slight drop in performance on saliency detection. We refer interested readers to the supplementary for qualitative results on saliency detection." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.315, + 0.892, + 0.392 + ], + "angle": 0, + "content": "Weakly supervised localization: We evaluate MOST on weakly supervised object localization on CUB-200 [55] and Imagenet [37] datasets respectively, and achieve a CorLoc of 92.42 (vs. 91.8 of TokenCut) on CUB-200 and a CorLoc of 71.4 (vs. 65.4 of TokenCut)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.4, + 0.688, + 0.416 + ], + "angle": 0, + "content": "4.6. Qualitative Results:" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.422, + 0.892, + 0.574 + ], + "angle": 0, + "content": "We illustrate qualitative results of MOST on VOC2007, 2012 and COCO datasets in Fig. 8. Fig. 8a shows results on VOC 2007 and 2012 and Fig. 8b shows results on COCO dataset. MOST is capable of localizing fairly complex scenes in all the three datasets. We observe that, such unsupervised localization methods are not limited by the categories annotated by humans but can localize regions of \"stuff\" like sign boards (third image in the first row of Fig. 8a right), rocks (last image of last row in Fig. 8b), and water bodies (first image in second row of Fig. 8b)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.586, + 0.619, + 0.601 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.611, + 0.892, + 0.822 + ], + "angle": 0, + "content": "We present MOST, an effective method for localizing multiple objects in complex images without a single annotation. MOST leverages object segmentation properties of transformers trained using DINO [3]. We show that the ability of MOST to localize multiple objects in an image is very effective on several object localization and discovery benchmarks. In particular, MOST outperforms recent state-of-the-art methods that train a class agnostic detector, on the task of single object localization, without any training. Further, we show that MOST achieves higher recall and covers more ground truth objects for a fixed set of boxes than LOST [41], a contemporary work on object localization. Finally, we extend MOST to the task of unsupervised saliency detection and report competitive results with recent works." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Acknowledgement. This project was partially supported by DARPA SemaFor (HR001119S0085) and DARPA SAIL-ON (W911NF2020009), and Amazon Research Award to Abhinav Shrivastava. Rama Chellappa was supported by an ONR MURI (N00014-20-1-2787)." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "15831" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.079, + 0.09, + 0.176, + 0.107 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.115, + 0.47, + 0.17 + ], + "angle": 0, + "content": "[1] Ankan Bansal, Sai Saketh Rambhatla, Abhinav Shrivastava, and Rama Chellappa. Detecting human-object interactions via functional generalization. Thirty-Fourth AAAI Conference on Artificial Intelligence, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.17, + 0.47, + 0.224 + ], + "angle": 0, + "content": "[2] Amir Bar, Xin Wang, Vadim Kantorov, Colorado J Reed, Roei Herzig, Gal Chechik, Anna Rohrbach, Trevor Darrell, and Amir Globerson. Detreg: Unsupervised pretraining with region priors for object detection, 2021. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.224, + 0.471, + 0.292 + ], + "angle": 0, + "content": "[3] Mathilde Caron, Hugo Touvron, Ishan Misra, Hervé Jégou, Julien Mairal, Piotr Bojanowski, and Armand Joulin. Emerging properties in self-supervised vision transformers. In Proceedings of the International Conference on Computer Vision (ICCV), 2021. 1, 2, 3, 5, 6, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.292, + 0.471, + 0.373 + ], + "angle": 0, + "content": "[4] Minsu Cho, Suha Kwak, Cordelia Schmid, and Jean Ponce. Unsupervised Object Discovery and Localization in the Wild: Part-based Matching with Bottom-up Region Proposals. In CVPR - IEEE Conference on Computer Vision & Pattern Recognition, pages 1201-1210, Boston, United States, June 2015. IEEE. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.374, + 0.471, + 0.442 + ], + "angle": 0, + "content": "[5] Yang Chuan, Zhang Lihe, Lu Huchuan Ruan Xiang, and Yang Ming-Hsuan. Saliency detection via graph-based manifold ranking. In Computer Vision and Pattern Recognition (CVPR), 2013 IEEE Conference on, pages 3166-3173. IEEE, 2013. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.442, + 0.471, + 0.551 + ], + "angle": 0, + "content": "[6] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. BERT: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers), pages 4171–4186, Minneapolis, Minnesota, June 2019. Association for Computational Linguistics. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.551, + 0.471, + 0.619 + ], + "angle": 0, + "content": "[7] Akshay Dhamija, Manuel Gunther, Jonathan Ventura, and Terrance Boult. The overlooked elephant of object detection: Open set. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision (WACV), March 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.619, + 0.471, + 0.674 + ], + "angle": 0, + "content": "[8] Carl Doersch, Abhinav Gupta, and Alexei A. Efros. Context as supervisory signal: Discovering objects with predictable context. In European Conference on Computer Vision (ECCV), pages 362-377. Springer, 2014. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.674, + 0.471, + 0.755 + ], + "angle": 0, + "content": "[9] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. ICLR, 2021. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.078, + 0.755, + 0.471, + 0.836 + ], + "angle": 0, + "content": "[10] Debidatta Dwibedi, Yusuf Aytar, Jonathan Tompson, Pierre Sermanet, and Andrew Zisserman. With a little help from my friends: Nearest-neighbor contrastive learning of visual representations. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 9588–9597, October 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.078, + 0.836, + 0.471, + 0.893 + ], + "angle": 0, + "content": "[11] Martin Ester, Hans-Peter Kriegel, Jörg Sander, and Xiaowei Xu. A density-based algorithm for discovering clusters in large spatial databases with noise. In Proceedings of the Second International Conference on Knowledge Discovery and" + }, + { + "type": "list", + "bbox": [ + 0.078, + 0.115, + 0.471, + 0.893 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.106 + ], + "angle": 0, + "content": "Data Mining, KDD'96, page 226-231. AAAI Press, 1996. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.106, + 0.892, + 0.16 + ], + "angle": 0, + "content": "[12] Mark Everingham, Luc Van Gool, Christopher K. I. Williams, John Winn, and Andrew Zisserman. The pascal visual object classes (voc) challenge. International Journal of Computer Vision, 88(2):303-338, 2010. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.16, + 0.892, + 0.214 + ], + "angle": 0, + "content": "[13] Georgia Gkioxari, Ross B. Girshick, Piotr Dólar, and Kaiming He. Detecting and recognizing human-object interactions. 2018 IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8359-8367, 2018. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.214, + 0.892, + 0.268 + ], + "angle": 0, + "content": "[14] Agrim Gupta, Piotr Dollar, and Ross Girshick. LVIS: A dataset for large vocabulary instance segmentation. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.268, + 0.892, + 0.337 + ], + "angle": 0, + "content": "[15] Kai Han, Sylvestre-Alvise Rebuffi, Sebastien Ehrhardt, Andrea Vedaldi, and Andrew Zisserman. Automatically discovering and learning new visual categories with ranking statistics. In Proceedings of the International Conference on Learning Representations (ICLR), 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.337, + 0.892, + 0.39 + ], + "angle": 0, + "content": "[16] Kai Han, Andrea Vedaldi, and Andrew Zisserman. Learning to discover novel visual categories via deep transfer clustering. In Proceedings of the International Conference on Computer Vision (ICCV), 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.391, + 0.892, + 0.445 + ], + "angle": 0, + "content": "[17] Kaiming He, X. Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 770-778, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.445, + 0.892, + 0.485 + ], + "angle": 0, + "content": "[18] Yen-Chang Hsu, Zhaoyang Lv, and Zsolt Kira. Deep image category discovery using a transferred similarity function. CoRR, abs/1612.01253, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.484, + 0.892, + 0.553 + ], + "angle": 0, + "content": "[19] Yen-Chang Hsu, Zhaoyang Lv, and Zsolt Kira. Learning to cluster in order to transfer across domains and tasks. In 6th International Conference on Learning Representations, ICLR 2018, Vancouver, BC, Canada, April 30 - May 3, 2018, Conference Track Proceedings, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.553, + 0.892, + 0.62 + ], + "angle": 0, + "content": "[20] Yen-Chang Hsu, Zhaoyang Lv, Joel Schlosser, Phillip Odom, and Zsolt Kira. Multi-class classification without multi-class labels. In 7th International Conference on Learning Representations, ICLR 2019, New Orleans, LA, USA, May 6-9, 2019, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.621, + 0.892, + 0.702 + ], + "angle": 0, + "content": "[21] Ranjay Krishna, Yuke Zhu, Oliver Groth, Justin Johnson, Kenji Hata, Joshua Kravitz, Stephanie Chen, Yannis Kalantidis, Li-Jia Li, David A. Shamma, Michael S. Bernstein, and Li Fei-Fei. Visual genome: Connecting language and vision using crowdsourced dense image annotations. International Journal of Computer Vision, 123:32-73, 2016. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.702, + 0.892, + 0.77 + ], + "angle": 0, + "content": "[22] Suha Kwak, Minsu Cho, Ivan Laptev, Jean Ponce, and Cordelia Schmid. Unsupervised Object Discovery and Tracking in Video Collections. In ICCV - IEEE International Conference on Computer Vision, pages 3173-3181, Santiago, Chile, Dec. 2015. IEEE. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.77, + 0.892, + 0.825 + ], + "angle": 0, + "content": "[23] Y. J. Lee and K. Grauman. Object-graphs for context-aware category discovery. In 2010 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 1-8, June 2010. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.825, + 0.892, + 0.864 + ], + "angle": 0, + "content": "[24] Yong Jae Lee and Kristen Grauman. Learning the easy things first: Self-paced visual category discovery. In CVPR, pages 1721-1728. IEEE, 2011. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.864, + 0.892, + 0.893 + ], + "angle": 0, + "content": "[25] Jian Li, Qian Du, and Caixin Sun. An improved box-counting method for image fractal dimension estimation." + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.893 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "15832" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.111, + 0.093, + 0.362, + 0.106 + ], + "angle": 0, + "content": "Pattern Recognit., 42:2460-2469, 2009. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.106, + 0.469, + 0.159 + ], + "angle": 0, + "content": "[26] Wang Lijun, Lu Huchuan, Wang Yifan, Feng Mengyang, Wang Dong, Yin Baocai, and Ruan Xiang. Learning to detect salient objects with image-level supervision. In CVPR, 2017. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.16, + 0.469, + 0.255 + ], + "angle": 0, + "content": "[27] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólár, and C. Lawrence Zitnick. Microsoft coco: Common objects in context. In David Fleet, Tomas Pajdla, Bernt Schiele, and Tinne Tuytelaars, editors, Computer Vision – ECCV 2014, pages 740–755, Cham, 2014. Springer International Publishing. 1, 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.256, + 0.469, + 0.297 + ], + "angle": 0, + "content": "[28] Jing Z. Liu, Luduan Zhang, and Guang H. Yue. Fractal dimension in human cerebellum measured by magnetic resonance imaging. Biophysical journal, 85 6:4041-6, 2003. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.297, + 0.469, + 0.337 + ], + "angle": 0, + "content": "[29] Cewu Lu, Ranjay Krishna, Michael Bernstein, and Li Fei-Fei. Visual relationship detection with language priors. In European Conference on Computer Vision, 2016. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.337, + 0.468, + 0.39 + ], + "angle": 0, + "content": "[30] Santiago Manen, Matthieu Guillaumin, and Luc Van Gool. Prime object proposals with randomized prim's algorithm. In 2013 IEEE International Conference on Computer Vision, pages 2536-2543, 2013. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.391, + 0.469, + 0.459 + ], + "angle": 0, + "content": "[31] Luke Melas-Kyriazi, Christian Rupprecht, Iro Laina, and Andrea Vedaldi. Deep spectral methods: A surprisingly strong baseline for unsupervised semantic segmentation and localization. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.459, + 0.469, + 0.526 + ], + "angle": 0, + "content": "[32] Duc Tam Nguyen, Maximilian Dax, Chaithanya Kumar Mummadi, Thi-Phuong-Nhung Ngo, Thi Hoai Phuong Nguyen, Zhongyu Lou, and Thomas Brox. Deepusps: Deep robust unsupervised saliency prediction with self-supervision. In NeurIPS, 2019. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.527, + 0.469, + 0.58 + ], + "angle": 0, + "content": "[33] Roy E Plotnick, Robert H Gardner, William W Hargrove, Karen Prestegaard, and Martin Perlmutter. Lacunarity analysis: a general technique for the analysis of spatial patterns. Physical review E, 53(5):5461, 1996. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.58, + 0.469, + 0.648 + ], + "angle": 0, + "content": "[34] Sai Saketh Rambhatla, Ramalingam Chellappa, and Abhinav Shrivastava. The pursuit of knowledge: Discovering and localizing novel categories using dual memory. 2021 IEEE/CVF International Conference on Computer Vision (ICCV), pages 9133-9143, 2021. 1, 2, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.649, + 0.469, + 0.729 + ], + "angle": 0, + "content": "[35] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. In C. Cortes, N. D. Lawrence, D. D. Lee, M. Sugiyama, and R. Garnett, editors, Advances in Neural Information Processing Systems 28, pages 91-99. Curran Associates, Inc., 2015. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.73, + 0.469, + 0.797 + ], + "angle": 0, + "content": "[36] Alvaro Collet Romea, Bo Xiong, Corina Gurau, Martial Hebert, and Siddhartha Srinivasa. Herbdisc: Towards lifelong robotic object discovery. In Proceedings of International Journal of Robotics Research (IJRR), January 2014. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.798, + 0.469, + 0.879 + ], + "angle": 0, + "content": "[37] Olga Russakovsky, Jia Deng, Hao Su, Jonathan Krause, Sanjeev Satheesh, Sean Ma, Zhiheng Huang, Andrej Karpathy, Aditya Khosla, Michael Bernstein, Alexander C. Berg, and Li Fei-Fei. ImageNet Large Scale Visual Recognition Challenge. International Journal of Computer Vision (IJCV), 115(3):211-252, 2015. 2, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.88, + 0.469, + 0.893 + ], + "angle": 0, + "content": "[38] Ville Satopaa, Jeannie Albrecht, David Irwin, and Barath" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.093, + 0.469, + 0.893 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.148 + ], + "angle": 0, + "content": "Raghavan. Finding a \"kneedle\" in a haystack: Detecting knee points in system behavior. In 2011 31st International Conference on Distributed Computing Systems Workshops, pages 166-171, 2011. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.148, + 0.892, + 0.201 + ], + "angle": 0, + "content": "[39] Jianbo Shi and Jitendra Malik. Normalized cuts and image segmentation. Proceedings of IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 731-737, 1997. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.202, + 0.892, + 0.255 + ], + "angle": 0, + "content": "[40] Jianping Shi, Qiong Yan, Li Xu, and Jiaya Jia. Hierarchical image saliency detection on extended cssd. IEEE Transactions on Pattern Analysis and Machine Intelligence, 38:717-729, 2016. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.256, + 0.892, + 0.337 + ], + "angle": 0, + "content": "[41] Oriane Simeoni, Gilles Puy, Huy V. Vo, Simon Roburin, Spyros Gidaris, Andrei Bursuc, Patrick Pérez, Renaud Marlet, and Jean Ponce. Localizing objects with self-supervised transformers and no labels. In Proceedings of the British Machine Vision Conference (BMVC), November 2021. 1, 2, 3, 4, 5, 6, 7, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.338, + 0.892, + 0.39 + ], + "angle": 0, + "content": "[42] Krishna Kumar Singh, Utkarsh Ojha, and Yong Jae Lee. Finegan: Unsupervised hierarchical disentanglement for fine-grained object generation and discovery. In CVPR, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.391, + 0.892, + 0.459 + ], + "angle": 0, + "content": "[43] J. Sivic, B. C. Russell, A. A. Efros, A. Zisserman, and W. T. Freeman. Discovering objects and their location in images. In Tenth IEEE International Conference on Computer Vision (ICCV'05) Volume 1, volume 1, pages 370-377 Vol. 1, Oct 2005. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.459, + 0.892, + 0.499 + ], + "angle": 0, + "content": "[44] T. G. Smith, G. D. Lange, and W. B. Marks. Fractal methods and results in cellular morphology — dimensions, lacunarity and multifractals, Nov. 1996. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.5, + 0.892, + 0.568 + ], + "angle": 0, + "content": "[45] Masato Tamura, Hiroki Ohashi, and Tomoaki Yoshinaga. Qpic: Query-based pairwise human-object interaction detection with image-wide contextual information. 2021 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 10405-10414, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.568, + 0.892, + 0.609 + ], + "angle": 0, + "content": "[46] J.R.R. Uijlings, K.E.A. van de Sande, T. Gevers, and A.W.M. Smeulders. Selective search for object recognition. International Journal of Computer Vision, 2013. 1, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.609, + 0.892, + 0.689 + ], + "angle": 0, + "content": "[47] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Proceedings of the 31st International Conference on Neural Information Processing Systems, NIPS'17, page 6000-6010, Red Hook, NY, USA, 2017. Curran Associates Inc. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.69, + 0.892, + 0.771 + ], + "angle": 0, + "content": "[48] Huy V. Vo, Francis Bach, Minsu Cho, Kai Han, Yann LeCun, Patrick Pérez, and Jean Ponce. Unsupervised image matching and object discovery as optimization. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 8287-8296, 2019. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.772, + 0.892, + 0.826 + ], + "angle": 0, + "content": "[49] Huy V. Vo, Patrick Pérez, and Jean Ponce. Toward unsupervised, multi-object discovery in large-scale image collections. In Proceedings of the European Conference on Computer Vision (ECCV), 2020. 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.826, + 0.892, + 0.88 + ], + "angle": 0, + "content": "[50] Huy V. Vo, Elena Sizikova, Cordelia Schmid, Patrick Pérez, and Jean Ponce. Large-scale unsupervised object discovery. In Advances in Neural Information Processing Systems 34 (NeurIPS), 2021. 1, 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.88, + 0.892, + 0.893 + ], + "angle": 0, + "content": "[51] Andrey Voynov, Stanislav Morozov, and Artem Babenko." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.893 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.957 + ], + "angle": 0, + "content": "15833" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.468, + 0.119 + ], + "angle": 0, + "content": "Object segmentation without labels with large-scale generative models. In ICML, 2021. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.12, + 0.469, + 0.187 + ], + "angle": 0, + "content": "[52] Tiancai Wang, Tong Yang, Martin Danelljan, Fahad Shahbaz Khan, X. Zhang, and Jian Sun. Learning human-object interaction detection using interaction points. 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4115-4124, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.187, + 0.469, + 0.255 + ], + "angle": 0, + "content": "[53] Yangtao Wang, Xi Shen, Shell Xu Hu, Yuan Yuan, James Crowley, and Dominique Vaufreydaz. Self-supervised transformers for unsupervised object discovery using normalized cut. In Conference on Computer Vision and Pattern Recognition, 2022. 1, 2, 3, 5, 6, 7, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.255, + 0.469, + 0.297 + ], + "angle": 0, + "content": "[54] Zhongdao Wang, Liang Zheng, Yixuan Liu, and Shengjin Wang. Towards real-time multi-object tracking. The European Conference on Computer Vision (ECCV), 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.296, + 0.469, + 0.349 + ], + "angle": 0, + "content": "[55] Peter Welinder, Steve Branson, Takeshi Mita, Catherine Wah, Florian Schroff, Serge Belongie, and Pietro Perona. Caltech-ucsd birds 200. Technical Report CNS-TR-201, Caltech, 2010. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.349, + 0.469, + 0.404 + ], + "angle": 0, + "content": "[56] Nicolai Wojke, Alex Bewley, and Dietrich Paulus. Simple online and realtime tracking with a deep association metric. In 2017 IEEE International Conference on Image Processing (ICIP), pages 3645-3649. IEEE, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.404, + 0.469, + 0.459 + ], + "angle": 0, + "content": "[57] Danfei Xu, Yuke Zhu, Christopher Bongsoo Choy, and Li Fei-Fei. Scene graph generation by iterative message passing. 2017 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3097-3106, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.459, + 0.469, + 0.513 + ], + "angle": 0, + "content": "[58] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable \\(\\{\\mathrm{detr}\\}\\): Deformable transformers for end-to-end object detection. In International Conference on Learning Representations, 2021. 5" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.513 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.956 + ], + "angle": 0, + "content": "15834" + } + ] +] \ No newline at end of file diff --git a/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/b6bef65d-9eb6-4535-9de8-7c08bf88dd4b_origin.pdf b/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/b6bef65d-9eb6-4535-9de8-7c08bf88dd4b_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..a0f84f1833ea660751cbf0c93f6c8ab1d2f8be61 --- /dev/null +++ b/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/b6bef65d-9eb6-4535-9de8-7c08bf88dd4b_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:850dc4074efeedb043bca534075ed767c9617c27a24c9c07b9bfc9538c0d047d +size 5003888 diff --git a/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/full.md b/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/full.md new file mode 100644 index 0000000000000000000000000000000000000000..f62b9844b13d3fe65d5e2d6e4467a6743a04de21 --- /dev/null +++ b/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/full.md @@ -0,0 +1,353 @@ +# MOST: Multiple Object localization with Self-supervised Transformers for object discovery + +Sai Saketh Rambhatla1,3* + +rssaketh@meta.com + +Ishan Misra + +imisra@meta.com + +Rama Chellappa2,3 + +rchella4@jhu.edu + +Abhinav Shrivastava3 + +abhinav@cs.umd.edu + +$^{1}$ Meta $^{2}$ Johns Hopkins University $^{3}$ University of Maryland, College Park + +# Abstract + +We tackle the challenging task of unsupervised object localization in this work. Recently, transformers trained with self-supervised learning have been shown to exhibit object localization properties without being trained for this task. In this work, we present Multiple Object localization with Self-supervised Transformers (MOST) that uses features of transformers trained using self-supervised learning to localize multiple objects in real world images. MOST analyzes the similarity maps of the features using box counting; a fractal analysis tool to identify tokens lying on foreground patches. The identified tokens are then clustered together, and tokens of each cluster are used to generate bounding boxes on foreground regions. Unlike recent state-of-the-art object localization methods, MOST can localize multiple objects per image and outperforms SOTA algorithms on several object localization and discovery benchmarks on PASCAL-VOC 07, 12 and COCO20k datasets. Additionally, we show that MOST can be used for self-supervised pretraining of object detectors, and yields consistent improvements on fully, semi-supervised object detection and unsupervised region proposal generation. Our project is publicly available at rssaketh.github.io/most. + +# 1. Introduction + +Object detectors are important components of several computer vision systems such as visual relationship detection [21, 29], human-object interaction detection [1, 13, 45, 52], scene graph generation [57] and object tracking [54, 56] etc. Performance of object detectors is heavily reliant on the availability of training data. However, annotating large object detection datasets can be expensive and time consuming [14, 27]. Additionally, the vocabulary of object detectors is limited by the training datasets and such detectors often fail to generalize to new cate + +![](images/61a59c0777062ed682651c552f2444d5158933def8ac3fbb7b3e4ec2d73aaffc.jpg) + +![](images/7f0260f7fe1aa8978cb4d27127c79235e429d9013382d289a53abe253dc87bb7.jpg) + +![](images/023633a71713b03fc570ea1713674f5ad5bdca26457fd2897f6a4d017a80855b.jpg) + +![](images/e64c0686e63d34c8002db11e89b86fc09c06703053cd1d8941d61f72abf61f30.jpg) +Figure 1: Top: Methods like LOST [41] (shown in figure), TokenCut [53] identify and localize the most salient foreground object and hence can detect only one object per image. Bottom: MOST is a simple, yet effective method that localizes multiple objects per image without training. + +![](images/e437b7faef62dc1a23f8dfb83d1966fd65a1c3f2b61b8b0d1aee43df4d2f1d54.jpg) + +![](images/5c0d0b1c0e8830ff68619378c9935da75155c2ba484d0460a04c23193bd89993.jpg) + +gories [7]. This strategy is not scalable and a more effective approach is warranted. Object discovery is one such task that has the potential to address these concerns. Object discovery is the problem of identifying and grouping objects/parts in a large collection of images without human intervention [23, 24, 36, 43]. The first step in object discovery is to obtain region proposals and subsequently group them semantically. Previous works on discovery used Selective Search [46], randomized Prim's [30] or a region proposal network (RPN) [35] to get object proposals. [48-50] used inter-image similarity to construct a graph and performed optimization or ranking, to localize objects without any supervision. Such methods are computationally expensive and often fail to scale to datasets larger than 20000 images. [34] used region proposals from an RPN and proposed a never ending learning approach and is the first method shown to scale to $\sim 100000$ images. However, these region proposal methods are often of low quality, and therefore reduce the performance of discovery systems. Recently, LOST [41] and TokenCut [53] leveraged the object segmentation properties of transformers [47] trained using self-supervised learning (DINO [3]) to obtain high quality object proposals. They demonstrate significant improvements over + +state-of-the-art on object discovery, salient object detection and weakly supervised object localization benchmarks. + +However, both LOST [41] and TokenCut [53] assume the presence of a single salient object per image and hence, can localize only one object as shown in Fig 1 (top). This assumption may hold for object centric datasets like ImageNet [37] but is not true for scene-centric real world datasets like PASCAL-VOC [12] and COCO [27]. In this work, we address the problem of localizing multiple objects per image and demonstrate the effectiveness of our approach for the task of unsupervised object localization and discovery on several standard benchmarks. + +We propose a new object localization method called "Multiple Object localization with Self-supervised Transformers" (MOST) which is capable of localizing multiple objects per image without using any labels. We use the features extracted from a transformer [47] network trained with DINO [3]. Our method is based on two empirical observations; 1) Patches within foreground objects have higher correlation with each other than the ones on the background [41] and 2) The similarity map computed using the features of a foreground object with all the features in the image is usually more localized and less noisier than the one computed using the feature of a background. Our algorithm analyzes the similarities between patches exhaustively using a fractal analysis tool called box counting [28]. This analysis picks a set of patches that most likely lie on foreground objects. Next, we perform clustering on the patch locations to group patches belonging to a foreground object together. Each of these clusters is called pools. A binary mask is then computed for each pool and a bounding box is extracted. This capability enables the algorithm to extract multiple bounding boxes per image as shown in Fig.1 (bottom). We demonstrate that without any training, our method can outperform state-of-the-art object localization methods that train class agnostic detectors to detect multiple objects. To prove the effectiveness of MOST, we demonstrate results on several object localization and discovery benchmarks. On self-supervised pre-training for object detectors, using MOST yields consistent improvement across multiple downstream tasks using $6 \times$ fewer boxes. When compared against other self-supervised transformer-based localization methods, MOST achieves higher recall with and without additional training. We summarize the contributions of our work below. + +- We propose MOST, an effective method to localize and discover multiple objects per image without supervision using transformers trained with DINO. +- We perform exhaustive experiments to assess the performance of MOST on several localization and discovery benchmarks and show significant improvements over the baselines. + +The paper is organized as follows. In Section 2 we discuss related works on object localization and discovery. We describe our approach in detail in Section 3. We describe our experimental setup and present results in Section 4 and conclude in Section 5. + +# 2. Related Works + +Unsupervised Object Localization and Discovery: Object category discovery can be broadly segregated into image-based [15, 16, 18-20, 42] and region-based methods [4, 8, 22-24, 34, 41, 48-50, 53]. Region-based methods start by generating object proposals and later group them into coherent semantic groups. Image-based approaches on the other hand, assume the localization task to be solved and focus solely on the semantic grouping. Our current method is closer to the former. Vo et al., [48-50] localize regions in images by constructing an inter-image similarity graph between regions and partitioning it using optimization or ranking. Due to the quadratic nature of the graph, these methods cannot scale to large datasets beyond tens of thousands of images. Our current work does not compute inter-image similarity between regions and scales linearly with number of images. Lee et al., [24] propose object graphs that incorporates knowledge about a few known categories to facilitate the discovery of novel categories. MOST doesn't assume any prior knowledge and has the ability to discover objects from scratch. Lee et al., [23] extend object graphs to a curriculum based discovery pipeline, that learns to discover easy objects first and progressively proceeds to discover the harder ones. Along similar lines, Rambhatla et al., [34] propose a large scale discovery pipeline, similar to [24] that leverages prior knowledge about a few categories. Authors of [34] use an RPN [35] trained on known categories as the localization method. In contrast to that, MOST localizes objects in images using features of a transformer [47] trained with DINO [3]. + +Object localization using self-supervised networks: Recently, CNNs [17] and Transformers [47] trained in a self-supervised fashion, have been shown to exhibit object localization/segmentation properties [3, 10]. This property is of particular interest as it has the potential to facilitate research on unsupervised localization, detection and segmentation. [41] is a simple method, based on the observation that the key features of the last self attention layer of a transformer, trained using DINO, has certain affinity. They construct a map of inverse degree to extract bounding boxes on objects in an unsupervised fashion. This method is shown to outperform recent state-of-the-art methods by a significant margin. [53] propose an alternate method for localizing objects using self-supervised transformers, based on normalized cut [39]. TokenCut [53] construct an undirected graph based on token feature similarities and use normalized cut to cluster foreground and background patches. SpectralCLUS + +![](images/ca286425971646cacee15f3b712ebf7dc91a261928ce96dc1b494574704b62a4.jpg) +Figure 2: Motivation for MOST: Example showing similarity maps of tokens within background and foreground for an image from the COCO dataset. Similarity maps of tokens within foreground patches are less random spatially. + +tering is used to solve the graph-cut and they show that the eigen vector corresponding to the second smallest eigenvalue provides a good cutting solution. TokenCut outperforms LOST on unsupervised object discovery. In addition to discovery, [53] also demonstrate impressive results on unsupervised saliency detection and weakly supervised object localization. Kyriazi et al., [31] propose deep spectral methods, that performs normalized cut [39] but using an affinity matrix computed using semantic and color features. Since this method is very similar to TokenCut and achieves lower performance, we only compare with the latter in this work. + +However, one limitation of LOST and TokenCut is that they can localize only one object per image. Our proposed method, MOST can automatically localize multiple objects per image and outperforms LOST and TokenCut on standard discovery benchmarks. + +# 3. Approach: MOST + +MOST can be used to localize multiple objects in an image. Our approach, illustrated in Fig. 3, first identifies a set of tokens that is computed from patches on foreground objects. These tokens are then clustered and each cluster, named pool, is used to obtain a bounding box. Next, we discuss a few preliminaries in Section 3.1 followed by the motivation and proposed solution in Section 3.2. + +# 3.1. Preliminaries + +Box Counting: Box counting is a method of analyzing a pattern by breaking and analyzing it at smaller scales. This is done by performing a raster scan of the pattern at different scales and computing appropriate metrics to assess its fractal nature. In this work, we use a sliding window scan. + +Vision Transformers: ViTs [9] operate on learned embeddings, called tokens, generated from non-overlapping image patches of resolution $\mathrm{P} \times \mathrm{P}$ (typically $\mathrm{P} = 8 / 16$ ) that form a sequence. To be precise, an image $\mathrm{I}$ of shape $H \times W \times 3$ is first divided into non-overlapping patches of resolution $P \times P \times 3$ , generating a total of $\mathrm{N} = HW / P^2$ patches. Next, each patch is embedded via a trainable linear layer to generate a token of dimension $d$ to form a sequence of patches. An extra [CLS] token [6] is added to this sequence, whose + +purpose is to aggregate the information from the tokens of the sequence. Typically, a projection head is attached to the [CLS] to train the network for classification. + +DINO: DINO [3] combines self-training and knowledge distillation without labels for self supervised learning. DINO constructs two global views and several local views of lower resolution, from an image. DINO consists of a teacher and a student network. The student processes all the crops while the teacher is operated only on the global crops. The teacher network then distills its dark knowledge to the student. This encourages the student network to learn local to global correspondences. In contrast to other knowledge distillation methods, DINO's teacher network is updated dynamically during training using exponential moving average. DINO was shown to perform on par or better than several baselines on several tasks of image retrieval, copy detection, instance segmentation etc. The property of importance to the current work, is the ability of DINO to localize foreground regions of semantic entities in an image. [41, 53] leverage this property to localize the salient object in an image by using the key features from the last self-attention layer. Similar to [41, 53], we concatenate the key features of all the heads in the last self-attention layer to obtain the input to MOST. + +# 3.2. Multiple object localization + +Motivation: Consider the example shown in Fig. 2. We show three examples of the similarity maps of a token (shown in red) picked on the background (column 2) and foreground (columns 3, 4). Tokens within foreground patches have higher correlation than the ones on background [41]. This results in the similarity maps of foreground patches being less "spatially" random than the ones on the background. The task then becomes to analyze the similarity maps and identify the ones with less spatial randomness. Box counting [25, 33] is a popular technique in fractal analysis that analyzes spatial patterns at different scales to extract desired properties. Hence, we adopt box counting for our case and since, we are interested in randomness, we adopt entropy as the metric. + +Preprocessing: The input to our method is a $d$ -dimensional feature $F \in \mathbb{R}^{N \times d}$ , extracted from an image using a neural network. Here, $N$ denotes the number of spatial locations in the feature map, in case of a CNN, or number of tokens, in case of a transformer network. The aim is to identify subsets of tokens, which we call pools, that can be used to localize all the objects in an image. We do not make any assumption on the number of objects present in the image. Given the feature $F$ , we compute an outer product matrix $A = F F^T \in \mathbb{R}^{N \times N}$ . Row $i$ of matrix $A$ , i.e., $A[i,:]$ encodes a similarity map of a token at location $i$ with all the other tokens in $F$ . Next, each row of $A$ is processed by the Entropy-based Box Analysis (EBA) module. + +![](images/a49e5e55d52837e112a80d00c3e228f880c9ae639797a84ed13c7b4b3663f899.jpg) +Figure 3: Overview of MOST: MOST operates on features extracted from transformers trained using DINO. The features are used to compute the outer product $A$ . Each row of $A$ is analyzed by the entropy-based box analysis (EBA) module that identifies tokens extracted from foreground patches. These patches are clustered using spatial locations as features to form pools. Each pool is then post-processed to generate a bounding box. + +Entropy-based Box Analysis (EBA): The proposed entropy based box analysis module performs a fractal analysis method, called box counting to segregate similarity maps of tokens on foreground patches from those of background. As shown in Fig. 3, we perform a raster scan with increasing box (used interchangeably with kernel in this work) sizes on each map. Traditionally, measures like lacunarity [44] are computed within each box to analyze the pattern. In this work, we average the elements within each box. This can be implemented efficiently using pooling operations. The resulting downsampled map is flattened and the entropy is computed using the pmf computed as follows: $p(x = x_{i}) = \sum_{i = 1}^{h.w}\frac{\mathbb{1}(f_{i} == x_{i})}{h.w}$ , where $f_{i}$ is the $i^{\text{th}}$ index in the feature map. A downsampled map belongs to a token on a foreground patch if its entropy is less than a threshold $\tau$ . Using $K$ boxes in the EBA module results in $K$ entropy values $e_k(k\in \{1,2,\dots ,K\})$ . Finally, we perform a majority voting among the entropies of all the downsampled maps, i.e., $\sum_{i = 1}^{K}\frac{\mathbb{1}(e_i\leq\tau)}{K} >0.5$ , to decide if the original similarity map belongs to a token on a foreground patch. A map of dimension $n\times n$ has a maximum entropy of $log(n^{2})$ . We use a threshold of the form $\tau = a + blog(n^{2})$ (we use $a = 1,b = 0.5$ in this work). We do not consider $\tau$ as a hyperparameter and we pick a value that is mid-way between the minimum and maximum permissible value $(b = 0.5)$ . To prevent a threshold of 0 for $n = 1$ , we add a constant $(a = 1)$ . + +Clustering: The EBA module, identifies a set $S = \{p|p\in$ + +$\{1,2,\dots ,N\}\}$ , that contains the spatial locations of tokens computed from foreground patches. Often, highly redundant neighboring tokens are identified. We group neighboring tokens with the help of a clustering step to obtain pools. We convert the linear index $p$ of the tokens to cartesian coordinates $(x,y)$ , and use that as the feature for clustering. Manhattan distance is used as the dissimilarity metric with a threshold $\epsilon$ ( $\epsilon = 2$ i.e. Moore neighborhood). Since, the number of pools is not known a-priori, we use a density-based clustering method, DBSCAN [11] which automatically identifies the number of clusters from the data. Pools identified by the clustering step are then post-processed to obtain bounding boxes on foreground objects. + +Post-processing: The clusters, called pools, obtained from the clustering step are then post-processed to obtain one box per pool. Consider $M$ pools identified by the clustering step, i.e. $\mathcal{C}_i$ , where $i \in \{1,2,\dots M\}$ . Each pool $\mathcal{C}_i$ is a set of token locations $\mathcal{C}_i = \{p^i | p^i \in \{1,2,\dots ,N\}\}$ . We leverage the first observation mentioned above to obtain a bounding box from the pool as follows. First, we build a binary similarity matrix $\hat{A} = A > 0$ . Next, within the tokens in the pool, we identify the one with lowest degree in $\hat{A}$ , called the core token, $c^*$ . + +$$ +c ^ {*} = \underset {c \in \mathcal {C} _ {i}} {\arg \min } d _ {c} \quad \text {w h e r e} \quad d _ {c} = \sum_ {j = 1} ^ {N} \hat {A} [ c, j ] +$$ + +Authors of LOST [41] report that tokens with low degrees + +Table 1: Results on unsupervised pre-training of object detectors. We train object detectors in a self-supervised fashion on the COCO dataset using different localization methods and compare their performance on the downstream tasks of semi and fully supervised object detection. COCO train set is used for fine-tuning and $k\%$ refers to the number of labeled samples used for training. Results are reported using AP[0.50:0.95] (denoted as AP), ${\mathrm{{AP}}}_{0.50}$ ,and ${\mathrm{{AP}}}_{0.75}$ on COCO validation set. + +
MethodBoxes per imageVOC 07+12COCO
k=10%fully supervisedk=1%k=2%k=5%fully supervised
APAP50AP75APAP50AP75APAPAP50
LOST [41]140.8860.3144.3663.5883.2770.4812.83 ± 0.3217.23 ± 0.3023.43 ± 0.3844.3062.80
TCut [53]141.1460.5944.3563.7983.5670.7013.13 ± 0.3817.27 ± 0.2123.27 ± 0.2343.8062.30
539.1257.5142.2963.4483.1470.3513.57 ± 0.3817.87 ± 0.3223.17 ± 0.4044.3062.80
SS [46]1040.7660.0044.4664.2383.4471.5513.73 ± 0.2918.00 ± 0.2622.83 ± 0.2543.9062.60
1542.1461.4145.8664.2483.7471.4113.87 ± 0.2918.23 ± 0.4023.13 ± 0.1144.3062.60
MOST4.6543.0363.2946.6164.3484.1271.7713.93 ± 0.3818.13 ± 0.2522.63 ± 0.1144.8063.50
SS3042.1261.2045.7164.8483.9871.7614.47 ± 0.3518.23 ± 0.4223.57 ± 0.2144.0062.30
MOST13.0944.4063.8348.2865.2484.2472.3714.83 ± 0.2118.30 ± 0.1723.43 ± 0.4545.2064.00
+ +most likely fall within an object. Next, we remove the tokens from the pool that do not correlate positively with $c^*$ to form a reduced pool $\mathcal{C}_i^*$ . This ensures that all the tokens in the current pool lie on the same foreground object. Next, a binary mask is constructed by computing the sum of similarities of token features in $\mathcal{C}_i^*$ with the features of all the tokens, i.e. $m_k^i = 11(\sum_{c\in \mathcal{C}_i^*}f_k^T f_c\geq 0)$ . Finally, connected component analysis is performed on the binary mask and the bounding box of the island that contains $c^*$ is selected as the region containing the object. We repeat this process for all the $M$ pools to generate $M$ bounding boxes per image. Note that, $M$ is not assumed to be known a-priori and is decided automatically by our method. Additionally, we remove trivial boxes i.e., boxes which have area less than than a threshold (256) or cover the whole image. + +Implementation Details: For all our experiments, we use the ViT-S/16 and ViT-B/8 [9] models trained with DINO [3] to extract the features. We concatenate the key features of all the heads from the last self-attention layer to use as the input to our method. + +# 4. Experiments + +In this section we describe, in detail, the experimental setup used for evaluation. We evaluate our method on two setups, namely the localization setup, and the discovery setup. We begin by describing the datasets and metrics in Sec. 4.1. We describe the evaluation setups in Sec. 4.2. Sec. 4.3 compares our method against contemporary work. We then describe ablation experiments in Sec. 4.4 and show qualitative results in Sec. 4.6. + +# 4.1. Datasets and Metrics + +We use the PASCAL-VOC [12] (2007, 2012 splits) and the COCO [27] (COCO20k [49] and COCO splits) datasets in our experiments. The PASCAL VOC [12] 2007 and 2012 + +trainval sets consists of 5011, 11540 images respectively, spanning twenty objects. The PASCAL VOC [12] test set consists of 4952 images. The COCO [27] 2014 train set consists of $\sim 110\mathrm{k}$ images containing over eighty objects and the COCO minimal set consists of 5000 images. We do not use any class or bounding box annotations for our method except for evaluation. + +For the localization setup, we use the average precision at different thresholds ([0.5:0.95], 0.5 and 0.75), average recall (AR1, AR10 and AR100) and Correct Localization (CorLoc) metrics for evaluation. CorLoc is defined as the fraction of the images in which atleast one object is localized with an IoU greater than a threshold (0.5 in this work). AP, AR are defined in the usual way. For the object discovery setup, we report both the PASCAL VOC style $\mathrm{AP}_{50}$ and COCO style $\mathrm{AP}_{[50:95]}$ metrics along with area under the purity-coverage plots [8, 34]. We refer the interested readers to [34] for definitions of purity and coverage. + +# 4.2. Setups + +Localization setup: This setup evaluates the localization performance of methods. We evaluate models on a) unsupervised pre-training, b) Multiple Object Localization, and c) single object localization. For unsupervised pre-training, localization methods are used to train object detectors in an unsupervised fashion and their performance is evaluated on the downstream task of object detection. In this work, we use the recently proposed DETReg [2] as the pre-training strategy which uses a Deformable DeTR [58] architecture. DETReg uses an object localization method and pre-trains an object detector in an unsupervised fashion. We evaluate the pre-trained model on the downstream tasks of semi-supervised, fully-supervised and class-agnostic object proposal generation. In the semi-supervised setting, models are trained on the PASCAL-VOC(07+12) and COCO train + +Table 2: Unsupervised class agnostic region proposal evaluation on COCO validation set: We compare the performance of region proposals for training DETReg. $Rk$ is Recall@k + +
MethodBoxes per imageAP\( AP_{50} \)\( AP_{75} \)R1R10R100
LOST [41]10.10.500.41.43.9
TCut [53]10.310.10.61.94.6
50.10.400.114.2
SS [46]100.10.300.11.14.4
150.10.300.114.1
300.10.300.114
MOST4.650.81.410.61.94.4
+ +Table 3: Results on object discovery: Comparison of MOST with recent works on unsupervised object discovery. We experiment with three cluster numbers, i.e., 20, 30, 40, on VOC 2007, 2007+12 and 80, 90, 100 on COCO20k. + +
Metric Train →VOC 2007VOC 07+12COCO20k
Clusters →2030402030408090100
APLOST [41]9.159.6410.1110.9512.1412.972.662.912.86
MOST9.2010.0711.0910.1212.8913.303.133.183.32
AP50LOST [41]26.3227.7829.4629.3533.2734.807.177.727.87
MOST25.3528.1931.3127.0434.4034.548.138.148.76
+ +Table 4: Results on single-object localization: Comparison of MOST with recent object discovery methods on VOC 07, 12 and COCO20k using CorLoc. + +
MethodVOC 07VOC 12COCO20k
rOSD [49]54.555.348.5
LOD [50]53.655.148.5
DINO-seg† [3]45.846.242.1
LOST [41]61.964.050.7
TokenCut [53]68.872.158.8
LOST [41] + CAD65.770.457.5
TCut [53]+CAD71.475.362.6
MOST74.877.467.1
+ +sets without labels and are fine-tuned on $k\%$ of labeled data similar to [2]. In the fully supervised setting, pre-trained models are fine-tuned on the full PASCAL-VOC and COCO dataset using all the labels. For the class-agnostic object proposal generation, models are pre-trained on COCO dataset without labels and the generated object proposals are evaluated on the COCO validation set similar to [2]. + +We follow the settings used in [50] for multiple-object localization and evaluate on PASCAL-VOC 2007 and COCO20k. For single-object localization, we follow the settings in [41, 53] and evaluate on PASCAL-VOC 2007, PASCAL-VOC 2012 and COCO20k. + +Discovery setup: This setup evaluates the object discovery performance. Similar to [41] we use the regions obtained by our localization method, to perform K-means clustering and use the resulting cluster labels to train Faster-RCNN object detectors on PASCAL-VOC 2007, 2012 trainval and COCO20k train sets. We report results of these experiments on the PASCAL-VOC 2007 test and COCO minival sets respectively. In addition to this, we report the performance of our discovery method on COCO train set, similar to the large scale discovery in [34]. + +# 4.3. Comparison with contemporary methods + +In this section we compare our method against contemporary works the localization and discovery setups. + +# 4.3.1 Localization setup + +Unsupervised Pre-training: Table 1 compares the results of all the localization methods on unsupervised pre-training of object detectors. We use average precision at different IoU thresholds ([0.50:0.95]: AP, 0.5: $\mathrm{AP}_{0.50}$ , 0.75: $\mathrm{AP}_{0.75}$ ) for evaluation. On the semi-supervised setting, on VOC $07 + 12$ ( $k = 10\%$ ), the self-supervised transformer based methods (LOST, TokenCut and MOST) outperform SS [46] with fewer boxes per image. In particular, TokenCut (denoted as TCut in Table 1) which outputs only one box per image, outperforms SS, using ten boxes per image, by $\sim 0.4$ + +points on mAP. MOST which outputs an average of 4.65 boxes per image outperforms TokenCut (the best performing self-supervised transformer based method) by 1.89, 2.7 and 2.26 percentage points on AP, $\mathrm{AP}_{50}$ , and $\mathrm{AP}_{75}$ respectively. This can be attributed to the ability of MOST to output multiple foreground regions resulting in more samples for pre-training which is not possible in the case of TokenCut. MOST outperforms SS, that outputs 30 boxes per image, by 0.91, 2.09 and 0.9 points on AP, $\mathrm{AP}_{50}$ , and $\mathrm{AP}_{75}$ respectively using almost $6\times$ fewer boxes per image and this can be attributed to the ability of MOST to generate high quality proposals. On COCO, MOST outperforms TokenCut by 0.8 and 0.86 on the $1\%$ and $2\%$ setting of semi-supervised learning. MOST with a ViT-B/8 backbone, that outputs 13.09 boxes on average per image, outperforms SS (with 30 boxes per image) by 0.36, 0.07 points on $k = 1\%$ and $k = 2\%$ few shot splits of COCO respectively. + +On the fully supervised setting, MOST outperforms LOST and TokenCut by 0.76 and 0.55 (AP) percentage points respectively on VOC 07+12. On COCO, MOST outperforms them by 0.50 and 1 points respectively. On VOC 07+12, MOST using ViT-B/8 (13.09 boxes per image) outperforms SS (with 30 boxes per image) by 0.40. On the much harder COCO dataset, MOST outperforms SS 1.20 (AP) percentage points using $2 \times$ fewer boxes per image. + +In Table 2 we report the class agnostic object proposal evaluation of DETReg trained using different localization methods. We report average precision at different IoU thresholds (AP, $\mathrm{AP}_{50}$ , $\mathrm{AP}_{75}$ ) and recall @ 1, 10 and 100 proposals per image (denoted as R1, R10, and R100) to evaluate the quality of region proposals. Note that the numbers in the table are low because of the unsupervised nature of training. All the self-supervised transformer-based methods achieve performance better than SS with far fewer boxes. In recall, TokenCut and MOST perform on par with each other and outperform rest of the methods with significant improvements. MOST achieves the highest performance on average precision among all the methods. It can achieve + +![](images/1812c514a3ca58d091197293527d3af10209491e8a4512da568b8e75248587b2.jpg) +k=1 + +![](images/5cef825af556d0688bd363a529c893966dc46af3dc0c484aea1fb9feaf41ee01.jpg) +k=3 + +![](images/becec42406bb0a5294841aa92dfa23a4be362abcfec37a51051330d13912d091.jpg) +k=5 + +![](images/6b54989c587365291834c1b104435a165a3e025e14a4e77453cd7e72a2b89a98.jpg) +k=1 + +![](images/2444333a3d0e9c4b53c1d9ad7736497c9ddcaf41b4b42c32d2c0bbd8398d68ed.jpg) +k=2 + +![](images/1ff923ab289a6f553b4149f73dd92552d11ca6d8600f37d309c55b6a1e606b26.jpg) +k=3 + +higher precision and recall because of its ability to output multiple high quality regions per image. While LOST and TokenCut output high quality boxes, they cannot output more than one box per image. SS on the other hand, outputs multiple boxes but with poor quality. + +Multiple Object Localization: We compare with LOD, the state-of-the-art method on the multi-object localization benchmark proposed by LOST using the code released by authors. On VOC2007, we attain an odAP[0.5:0.95] of 6.43 compared to 5.35 attained by LOD, an improvement of 1.09 percentage points. On the COCO20k dataset, we attain a performance of 1.70 (compared to 1.53 achieved by LOD) on the harder odAP[0.50:0.95] metric. Note, we do not compare with rOSD [49] as LOD [50] outperforms it. + +Single Object Localization: Table 4 compares the results of our method on single object localization with recent methods on PASCAL VOC 2007, 2012 and COCO20k respectively. We use the CorLoc metric to evaluate methods. Note that MOST is a multiple object localization method and this setup evaluates the ability of methods to output a single region. Since MOST outputs multiple boxes, we use the heuristic, average best overlap (for evaluating object proposals in [46]), to select one region per image. The numbers reported for MOST in this table are the "best" case scenario. We outperform LOST by 12.9, 13.4 and 16.4 percentage points on VOC 2007, 2012 and COCO20k respectively. We outperform TokenCut [53] by 6, 5.3 and 8.3 percentage points on the three datasets respectively. To obtain multiple regions per image, authors of LOST train a foreground object detector using the regions obtained by their method as supervision, called LOST+CAD [41]. This method can output multiple boxes per image and from Table 4, even without any training, our method outperforms LOST+CAD and TokenCut+CAD by 9.1, 7, 9.6 and 3.4, 2.1, 4.5 percentage points on VOC 2007, 2012 and COCO20k respectively. + +![](images/010347b59054872fef604556ece16985ab91d6365d4ca175344e727748b5dd51.jpg) + +![](images/4f7ae4bfa2cbc7382b89e488d51cd4abedb920a2cbf08157c833d2ddb57cd7e8.jpg) + +![](images/525d2ac72d6b24c4c0623acf84b0c63b906b8b377cbec83fc10c3e431982134e.jpg) +Figure 4: Effect of kernel size: Different kernel sizes can identify different tokens as belonging to the foreground. Multiple kernels help eliminate noisy predictions (first triplet) and missed predictions (second triplet). +Figure 5: Figure demonstrating the effect of clustering in MOST: Each image consists of a bounding box generated from a pool. We observe that each pool focuses on different foreground instance. + +![](images/480e4d325d6557577d4d05c05a5fc987019fb8b3a6f6305cd1b54517085c7ac4.jpg) + +![](images/f4fda4b897aeb4e8590f31d2437da3f249e09a39aecee38cfb45a2e124e1f5fe.jpg) +Figure 6: Figure demonstrating the effect of clustering in MOST. Eliminating the clustering results in noisier outputs. + +![](images/26ff3ae1e3c2dc6a1b0328cb2381d62833af696b2f4a15af57e17d84e1b132f7.jpg) + +![](images/03da880ef6407f4afd06eef657b13ebcc2340098742602d56df19d668b0975dd.jpg) + +![](images/409d4e0ba1560f9f508de4c72407b3ee65add926faf33788dc51474bba082699.jpg) + +Discovery Setup: This setup evaluates the true object discovery performance as the localized boxes are used to discover semantic groups. Following LOST [41], we first cluster the features of the localized objects using K-means clustering. For VOC 2007 and $2007 + 2012$ trainval splits, we use 20, 30 and 40 clusters. We use 80, 90 and 100 clusters for COCO20k train split. We report the results of experiments on VOC 2007, $07 + 12$ trainval sets on VOC 2007 test set. For experiments on COCO20k, we report results on the COCO validation set. Results are tabulated in Table 3. MOST outperforms LOST in most settings with the margin of improvement higher for more number of clusters and more cluttered datasets like COCO. For more details on clustering and training refer to supplementary. + +Finally, we evaluate the performance of MOST on large-scale object discovery setup introduced in [34]. For this setup, we use the area under the purity coverage plot as the metric. [34] automatically identifies the number of clusters and obtains an AuC@0.5 of $3.6\%$ on the COCO 2014 train set. We extract the DINO [CLS] token features of regions obtained from MOST for K-Means clustering. To avoid specifying the number of clusters manually, we employ the "kneedle" method [38] to get the optimal number of clusters (more details in supplementary). Next, we randomly sample 10000 features from the whole dataset and cluster them using K-means with the optimal number of clusters. This subsampling avoids loading all the features into mem + +![](images/af60b2091b25194435a10fdb72d50c7ae4dd7351552d05fff911fbaf9add310c.jpg) +Figure 7: Recall analysis: Comparison of recall values of MOST, MOST+CAD with LOST and LOST+CAD. LOST generates one bounding box per image. MOST+CAD, MOST have higher recall and cover more ground-truth objects for a fixed set of boxes. + +ory. MOST + optimal K-means achieves an AuC@0.5 of $8.74\%$ on COCO 2014 train set. We use the cluster labels to train an object detector on the COCO train set and achieve an $\mathrm{AP / AP}_{50}$ of $3.9 / 9.5\%$ compared to $5.2\%$ $\mathrm{AP}_{50}$ obtained by [34] on COCO validation set. For more experiments on unsupervised saliency detection and weakly supervised localization, refer to the supplementary. + +# 4.4. Ablation Experiments + +Effect of kernel size: The EBA module performs box analysis in a sliding window fashion using boxes (or kernels) of different sizes. We implement this efficiently using a pooling operation. We visualize the effect of the size of pooling kernels on the final output in Fig. 4. We observe that the majority voting performed in EBA, helps in removing noisy predictions in the first triplet, where a box identified by kernel of size 1 is eliminated by majority voting of kernels with larger receptive field. In the second triplet in Fig. 4, an object which was missed by the lower order kernels $(\mathrm{k} = [1,4])$ , can be picked up with a higher order kernel $(\mathrm{k} = 5)$ . For all our experiments, we use kernels of sizes upto 5 (i.e. $\mathrm{k} = [1,5]$ ). For quantitative results on the effect of kernel sizes, refer to the supplementary. + +Effect of clustering: MOST performs clustering with the token locations as features to obtain pools. Each pool contains tokens belonging to a foreground object. We show the effect of clustering qualitatively in Fig. 5. We observe that each pool focuses on one foreground object and illustrate the bounding boxes extracted from each pool. + +Each pool contains tokens belonging to a foreground object. We show the effect of forming pools qualitatively in Fig. 6. The first image in each pair shows the output of MOST without clustering to form pools and the second image shows the output with the formation. We observe that, without clustering, each token can generate a bounding box resulting in noisier outputs. + +Recall of boxes: To analyze the object localization perfor + +Table 5: Effect of backbone on single-object localization + +
BackboneVOC 2007VOC 2012COCO20k
ViT-S/884.2586.0080.50
ViT-S/1674.8077.4068.60
ViT-B/885.4087.0081.73
ViT-B/1672.7276.2867.20
+ +mance of MOST, we compare its recall with LOST and TokenCut on VOC 07, 12 and COCO20k datasets in Fig. 7. The x-axis represents the maximum number of boxes allowed per image and the y axis plots the recall. LOST and TokenCut generate only one box per image and hence have fixed recall in all the plots. MOST can generate more boxes and hence have higher recall than LOST and TokenCut. [41] trains a class agnostic detector (CAD) to output multiple boxes per image using the output of LOST as supervision. Without a single step of training, MOST performs competitively against LOST+CAD on all the datasets. With a class agnostic detector, MOST+CAD outperforms LOST, TokenCut and their CAD counterparts comfortably on all the datasets. On COCO20k, a much harder dataset, MOST+CAD outperforms all the methods with a significant margin demonstrating its superior localization abilities. + +Effect of EBA: We study the effect of EBA on single-object localization. The task of the EBA module is to identify tokens on foreground instances from similarity maps. We replace the EBA module with the strategy used by LOST [41], effectively giving LOST the ability to localize multiple objects. We use top-100 patches and this system achieves a CorLoc of 63.66 (compared to 74.84 of MOST). The EBA module can automatically pick the right tokens, unlike LOST to localize multiple objects. This experiment demonstrates the benefit of the proposed EBA module. + +Timing analysis: MOST can localize multiple objects per image and does so by analyzing the similarity maps of all the tokens which is computationally more expensive. To understand this requirement, we perform a timing analysis. On average, LOST takes 0.008s per image while MOST takes 0.3s. MOST obtains a recall of 0.19, 0.21, and 0.08 on VOC07, VOC12, and COCO20k respectively (compared to 0.13, 0.15, and 0.03 of LOST). This translates to localizing an additional 750, 2400, and 7200 instances than LOST on VOC07, VOC12, and COCO20k respectively. We believe the additional time taken by MOST is justified by the improvement in recall performance which is essential for an object localization method. + +Effect of backbone: We study the effect of backbone on MOST in Table 5. We observe that backbones with a smaller patch size can localize more objects, especially smaller ones (refer to supplementary for qualitative results) + +![](images/0aff19d213a50846bc9baab00f055f202ab4631c7d08ca181a3506ac8ee550d5.jpg) + +![](images/1aa69e756f27a3c28756b6a3ce7627c833f3a4f16b977bcf587e18d6a49c1dcc.jpg) + +![](images/e93b608b8f73d927ad44349baa5df2eef466966e078b3a80bd631b77b906a0e4.jpg) + +![](images/fef149cf998a49f473e54abd7407ee942bf6475d9598c03a7716cad7fbfdae42.jpg) + +![](images/261952cba14f3e6bc96bd1ff5969acd501d588a312643ee40d19633c27a5bba5.jpg) + +![](images/a900dbf02e419bf63da109f5f49292f67c8f1d84130624bd2a63d667b9001060.jpg) + +![](images/a8e2c006c95c3b07b22dc9959dff16dc33a6c8eb9fb5cc9e504ad29c41beec49.jpg) + +![](images/235f62354645ddafbf698dc5ebae130d5d6733189102d6d48a7374453ddaf205.jpg) + +![](images/27af0758d2f87a029aff3ab79076317d5e0a9f218945d99326e376020f973dce.jpg) +(a) VOC 07+12 + +![](images/087da7178ef671c5d2e5f47c8f7fb7ed50313d4407cb5e939b3ffb9303c488ed.jpg) +Figure 8: Qualitative results of MOST on VOC 07, 12 and COCO: MOST can localize multiple objects in cluttered scenes without training. Localization ability of MOST is not limited by the biases of annotators and can localize rocks, mountains, branches, water bodies, etc. + +![](images/8e57c3b2f8693e9c9af96d34a03291c0db18f338f42ed2a256f057b8bbd16b47.jpg) + +![](images/59139d447aa3fddc3d05bb8092541a23300a49e41a88f74b1737249351c3664d.jpg) +(b) COCO + +![](images/0f8107af5ca39d2fee6a948fc7de1a365c7a8ba61acf60733d4d0267af3fbcbd.jpg) + +Table 6: Results on unsupervised saliency detection: We compare MOST to state-of-the-art unsupervised saliency detections methods. Top results are in bold and second best is highlighted in blue. Ability to detect multiple objects in images is a good tradeoff for a slight drop in performance on saliency detection + +
MethodECSSDDUTSDUT-OMRON
max Fβ IoU Acc (%)max Fβ IoU Acc (%)max Fβ IoU Acc (%)
DeepUSPS[32]58.444.079.542.530.577.341.430.577.9
BigBiGAN [51]78.267.289.960.849.887.854.945.385.6
E-BigBiGAN [51]79.768.490.662.451.188.256.346.486.0
LOST [41]75.762.588.061.852.087.147.440.279.6
TCut [53]80.371.291.867.257.690.360.053.388.0
MOST79.163.189.066.653.889.757.047.587.0
+ +resulting in a higher CorLoc. This comes at a cost of producing noisier outputs. We refer interested readers to the supplementary for more analysis and qualitative results on the effect of backbones and patch sizes. + +# 4.5. Additional Experiments + +Unsupervised Saliency Detection: MOST can easily be extended to unsupervised saliency detection. We experiment with ECSSD [40], DUTS [26] and DUT-OMRON [5] datasets and use the metrics used by [41, 53] for evaluation. All these datasets require methods to segment the salient object in an image. Hence, naively using MOST doesn't perform well. To extend MOST for saliency detection, we select the largest pool and use the similarity map computed using its tokens as the saliency map. In Table 6, we compare MOST with TokenCut and LOST on the three datasets. MOST outperforms LOST comfortably on all the metrics, datasets and fares competitively against TokenCut. We believe that the ability to detect multiple objects in images is a good tradeoff for a slight drop in performance on saliency detection. We refer interested readers to the supplementary for qualitative results on saliency detection. + +Weakly supervised localization: We evaluate MOST on weakly supervised object localization on CUB-200 [55] and Imagenet [37] datasets respectively, and achieve a CorLoc of 92.42 (vs. 91.8 of TokenCut) on CUB-200 and a CorLoc of 71.4 (vs. 65.4 of TokenCut). + +# 4.6. Qualitative Results: + +We illustrate qualitative results of MOST on VOC2007, 2012 and COCO datasets in Fig. 8. Fig. 8a shows results on VOC 2007 and 2012 and Fig. 8b shows results on COCO dataset. MOST is capable of localizing fairly complex scenes in all the three datasets. We observe that, such unsupervised localization methods are not limited by the categories annotated by humans but can localize regions of "stuff" like sign boards (third image in the first row of Fig. 8a right), rocks (last image of last row in Fig. 8b), and water bodies (first image in second row of Fig. 8b). + +# 5. Conclusion + +We present MOST, an effective method for localizing multiple objects in complex images without a single annotation. MOST leverages object segmentation properties of transformers trained using DINO [3]. We show that the ability of MOST to localize multiple objects in an image is very effective on several object localization and discovery benchmarks. In particular, MOST outperforms recent state-of-the-art methods that train a class agnostic detector, on the task of single object localization, without any training. Further, we show that MOST achieves higher recall and covers more ground truth objects for a fixed set of boxes than LOST [41], a contemporary work on object localization. Finally, we extend MOST to the task of unsupervised saliency detection and report competitive results with recent works. + +Acknowledgement. This project was partially supported by DARPA SemaFor (HR001119S0085) and DARPA SAIL-ON (W911NF2020009), and Amazon Research Award to Abhinav Shrivastava. Rama Chellappa was supported by an ONR MURI (N00014-20-1-2787). + +# References + +[1] Ankan Bansal, Sai Saketh Rambhatla, Abhinav Shrivastava, and Rama Chellappa. Detecting human-object interactions via functional generalization. Thirty-Fourth AAAI Conference on Artificial Intelligence, 2020. 1 +[2] Amir Bar, Xin Wang, Vadim Kantorov, Colorado J Reed, Roei Herzig, Gal Chechik, Anna Rohrbach, Trevor Darrell, and Amir Globerson. Detreg: Unsupervised pretraining with region priors for object detection, 2021. 5, 6 +[3] Mathilde Caron, Hugo Touvron, Ishan Misra, Hervé Jégou, Julien Mairal, Piotr Bojanowski, and Armand Joulin. Emerging properties in self-supervised vision transformers. In Proceedings of the International Conference on Computer Vision (ICCV), 2021. 1, 2, 3, 5, 6, 9 +[4] Minsu Cho, Suha Kwak, Cordelia Schmid, and Jean Ponce. Unsupervised Object Discovery and Localization in the Wild: Part-based Matching with Bottom-up Region Proposals. In CVPR - IEEE Conference on Computer Vision & Pattern Recognition, pages 1201-1210, Boston, United States, June 2015. IEEE. 2 +[5] Yang Chuan, Zhang Lihe, Lu Huchuan Ruan Xiang, and Yang Ming-Hsuan. Saliency detection via graph-based manifold ranking. In Computer Vision and Pattern Recognition (CVPR), 2013 IEEE Conference on, pages 3166-3173. IEEE, 2013. 9 +[6] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. BERT: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers), pages 4171–4186, Minneapolis, Minnesota, June 2019. Association for Computational Linguistics. 3 +[7] Akshay Dhamija, Manuel Gunther, Jonathan Ventura, and Terrance Boult. The overlooked elephant of object detection: Open set. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision (WACV), March 2020. 1 +[8] Carl Doersch, Abhinav Gupta, and Alexei A. Efros. Context as supervisory signal: Discovering objects with predictable context. In European Conference on Computer Vision (ECCV), pages 362-377. Springer, 2014. 2, 5 +[9] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. ICLR, 2021. 3, 5 +[10] Debidatta Dwibedi, Yusuf Aytar, Jonathan Tompson, Pierre Sermanet, and Andrew Zisserman. With a little help from my friends: Nearest-neighbor contrastive learning of visual representations. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 9588–9597, October 2021. 2 +[11] Martin Ester, Hans-Peter Kriegel, Jörg Sander, and Xiaowei Xu. A density-based algorithm for discovering clusters in large spatial databases with noise. In Proceedings of the Second International Conference on Knowledge Discovery and + +Data Mining, KDD'96, page 226-231. AAAI Press, 1996. 4 +[12] Mark Everingham, Luc Van Gool, Christopher K. I. Williams, John Winn, and Andrew Zisserman. The pascal visual object classes (voc) challenge. International Journal of Computer Vision, 88(2):303-338, 2010. 2, 5 +[13] Georgia Gkioxari, Ross B. Girshick, Piotr Dólar, and Kaiming He. Detecting and recognizing human-object interactions. 2018 IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8359-8367, 2018. 1 +[14] Agrim Gupta, Piotr Dollar, and Ross Girshick. LVIS: A dataset for large vocabulary instance segmentation. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2019. 1 +[15] Kai Han, Sylvestre-Alvise Rebuffi, Sebastien Ehrhardt, Andrea Vedaldi, and Andrew Zisserman. Automatically discovering and learning new visual categories with ranking statistics. In Proceedings of the International Conference on Learning Representations (ICLR), 2020. 2 +[16] Kai Han, Andrea Vedaldi, and Andrew Zisserman. Learning to discover novel visual categories via deep transfer clustering. In Proceedings of the International Conference on Computer Vision (ICCV), 2019. 2 +[17] Kaiming He, X. Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 770-778, 2016. 2 +[18] Yen-Chang Hsu, Zhaoyang Lv, and Zsolt Kira. Deep image category discovery using a transferred similarity function. CoRR, abs/1612.01253, 2016. 2 +[19] Yen-Chang Hsu, Zhaoyang Lv, and Zsolt Kira. Learning to cluster in order to transfer across domains and tasks. In 6th International Conference on Learning Representations, ICLR 2018, Vancouver, BC, Canada, April 30 - May 3, 2018, Conference Track Proceedings, 2018. +[20] Yen-Chang Hsu, Zhaoyang Lv, Joel Schlosser, Phillip Odom, and Zsolt Kira. Multi-class classification without multi-class labels. In 7th International Conference on Learning Representations, ICLR 2019, New Orleans, LA, USA, May 6-9, 2019, 2019. 2 +[21] Ranjay Krishna, Yuke Zhu, Oliver Groth, Justin Johnson, Kenji Hata, Joshua Kravitz, Stephanie Chen, Yannis Kalantidis, Li-Jia Li, David A. Shamma, Michael S. Bernstein, and Li Fei-Fei. Visual genome: Connecting language and vision using crowdsourced dense image annotations. International Journal of Computer Vision, 123:32-73, 2016. 1 +[22] Suha Kwak, Minsu Cho, Ivan Laptev, Jean Ponce, and Cordelia Schmid. Unsupervised Object Discovery and Tracking in Video Collections. In ICCV - IEEE International Conference on Computer Vision, pages 3173-3181, Santiago, Chile, Dec. 2015. IEEE. 2 +[23] Y. J. Lee and K. Grauman. Object-graphs for context-aware category discovery. In 2010 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 1-8, June 2010. 1, 2 +[24] Yong Jae Lee and Kristen Grauman. Learning the easy things first: Self-paced visual category discovery. In CVPR, pages 1721-1728. IEEE, 2011. 1, 2 +[25] Jian Li, Qian Du, and Caixin Sun. An improved box-counting method for image fractal dimension estimation. + +Pattern Recognit., 42:2460-2469, 2009. 3 +[26] Wang Lijun, Lu Huchuan, Wang Yifan, Feng Mengyang, Wang Dong, Yin Baocai, and Ruan Xiang. Learning to detect salient objects with image-level supervision. In CVPR, 2017. 9 +[27] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólár, and C. Lawrence Zitnick. Microsoft coco: Common objects in context. In David Fleet, Tomas Pajdla, Bernt Schiele, and Tinne Tuytelaars, editors, Computer Vision – ECCV 2014, pages 740–755, Cham, 2014. Springer International Publishing. 1, 2, 5 +[28] Jing Z. Liu, Luduan Zhang, and Guang H. Yue. Fractal dimension in human cerebellum measured by magnetic resonance imaging. Biophysical journal, 85 6:4041-6, 2003. 2 +[29] Cewu Lu, Ranjay Krishna, Michael Bernstein, and Li Fei-Fei. Visual relationship detection with language priors. In European Conference on Computer Vision, 2016. 1 +[30] Santiago Manen, Matthieu Guillaumin, and Luc Van Gool. Prime object proposals with randomized prim's algorithm. In 2013 IEEE International Conference on Computer Vision, pages 2536-2543, 2013. 1 +[31] Luke Melas-Kyriazi, Christian Rupprecht, Iro Laina, and Andrea Vedaldi. Deep spectral methods: A surprisingly strong baseline for unsupervised semantic segmentation and localization. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 3 +[32] Duc Tam Nguyen, Maximilian Dax, Chaithanya Kumar Mummadi, Thi-Phuong-Nhung Ngo, Thi Hoai Phuong Nguyen, Zhongyu Lou, and Thomas Brox. Deepusps: Deep robust unsupervised saliency prediction with self-supervision. In NeurIPS, 2019. 9 +[33] Roy E Plotnick, Robert H Gardner, William W Hargrove, Karen Prestegaard, and Martin Perlmutter. Lacunarity analysis: a general technique for the analysis of spatial patterns. Physical review E, 53(5):5461, 1996. 3 +[34] Sai Saketh Rambhatla, Ramalingam Chellappa, and Abhinav Shrivastava. The pursuit of knowledge: Discovering and localizing novel categories using dual memory. 2021 IEEE/CVF International Conference on Computer Vision (ICCV), pages 9133-9143, 2021. 1, 2, 5, 6, 7, 8 +[35] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. In C. Cortes, N. D. Lawrence, D. D. Lee, M. Sugiyama, and R. Garnett, editors, Advances in Neural Information Processing Systems 28, pages 91-99. Curran Associates, Inc., 2015. 1, 2 +[36] Alvaro Collet Romea, Bo Xiong, Corina Gurau, Martial Hebert, and Siddhartha Srinivasa. Herbdisc: Towards lifelong robotic object discovery. In Proceedings of International Journal of Robotics Research (IJRR), January 2014. 1 +[37] Olga Russakovsky, Jia Deng, Hao Su, Jonathan Krause, Sanjeev Satheesh, Sean Ma, Zhiheng Huang, Andrej Karpathy, Aditya Khosla, Michael Bernstein, Alexander C. Berg, and Li Fei-Fei. ImageNet Large Scale Visual Recognition Challenge. International Journal of Computer Vision (IJCV), 115(3):211-252, 2015. 2, 9 +[38] Ville Satopaa, Jeannie Albrecht, David Irwin, and Barath + +Raghavan. Finding a "kneedle" in a haystack: Detecting knee points in system behavior. In 2011 31st International Conference on Distributed Computing Systems Workshops, pages 166-171, 2011. 7 +[39] Jianbo Shi and Jitendra Malik. Normalized cuts and image segmentation. Proceedings of IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 731-737, 1997. 2, 3 +[40] Jianping Shi, Qiong Yan, Li Xu, and Jiaya Jia. Hierarchical image saliency detection on extended cssd. IEEE Transactions on Pattern Analysis and Machine Intelligence, 38:717-729, 2016. 9 +[41] Oriane Simeoni, Gilles Puy, Huy V. Vo, Simon Roburin, Spyros Gidaris, Andrei Bursuc, Patrick Pérez, Renaud Marlet, and Jean Ponce. Localizing objects with self-supervised transformers and no labels. In Proceedings of the British Machine Vision Conference (BMVC), November 2021. 1, 2, 3, 4, 5, 6, 7, 8, 9 +[42] Krishna Kumar Singh, Utkarsh Ojha, and Yong Jae Lee. Finegan: Unsupervised hierarchical disentanglement for fine-grained object generation and discovery. In CVPR, 2019. 2 +[43] J. Sivic, B. C. Russell, A. A. Efros, A. Zisserman, and W. T. Freeman. Discovering objects and their location in images. In Tenth IEEE International Conference on Computer Vision (ICCV'05) Volume 1, volume 1, pages 370-377 Vol. 1, Oct 2005. 1 +[44] T. G. Smith, G. D. Lange, and W. B. Marks. Fractal methods and results in cellular morphology — dimensions, lacunarity and multifractals, Nov. 1996. 4 +[45] Masato Tamura, Hiroki Ohashi, and Tomoaki Yoshinaga. Qpic: Query-based pairwise human-object interaction detection with image-wide contextual information. 2021 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 10405-10414, 2021. 1 +[46] J.R.R. Uijlings, K.E.A. van de Sande, T. Gevers, and A.W.M. Smeulders. Selective search for object recognition. International Journal of Computer Vision, 2013. 1, 5, 6, 7 +[47] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Proceedings of the 31st International Conference on Neural Information Processing Systems, NIPS'17, page 6000-6010, Red Hook, NY, USA, 2017. Curran Associates Inc. 1, 2 +[48] Huy V. Vo, Francis Bach, Minsu Cho, Kai Han, Yann LeCun, Patrick Pérez, and Jean Ponce. Unsupervised image matching and object discovery as optimization. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 8287-8296, 2019. 1, 2 +[49] Huy V. Vo, Patrick Pérez, and Jean Ponce. Toward unsupervised, multi-object discovery in large-scale image collections. In Proceedings of the European Conference on Computer Vision (ECCV), 2020. 5, 6, 7 +[50] Huy V. Vo, Elena Sizikova, Cordelia Schmid, Patrick Pérez, and Jean Ponce. Large-scale unsupervised object discovery. In Advances in Neural Information Processing Systems 34 (NeurIPS), 2021. 1, 2, 6, 7 +[51] Andrey Voynov, Stanislav Morozov, and Artem Babenko. + +Object segmentation without labels with large-scale generative models. In ICML, 2021. 9 +[52] Tiancai Wang, Tong Yang, Martin Danelljan, Fahad Shahbaz Khan, X. Zhang, and Jian Sun. Learning human-object interaction detection using interaction points. 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4115-4124, 2020. 1 +[53] Yangtao Wang, Xi Shen, Shell Xu Hu, Yuan Yuan, James Crowley, and Dominique Vaufreydaz. Self-supervised transformers for unsupervised object discovery using normalized cut. In Conference on Computer Vision and Pattern Recognition, 2022. 1, 2, 3, 5, 6, 7, 9 +[54] Zhongdao Wang, Liang Zheng, Yixuan Liu, and Shengjin Wang. Towards real-time multi-object tracking. The European Conference on Computer Vision (ECCV), 2020. 1 +[55] Peter Welinder, Steve Branson, Takeshi Mita, Catherine Wah, Florian Schroff, Serge Belongie, and Pietro Perona. Caltech-ucsd birds 200. Technical Report CNS-TR-201, Caltech, 2010. 9 +[56] Nicolai Wojke, Alex Bewley, and Dietrich Paulus. Simple online and realtime tracking with a deep association metric. In 2017 IEEE International Conference on Image Processing (ICIP), pages 3645-3649. IEEE, 2017. 1 +[57] Danfei Xu, Yuke Zhu, Christopher Bongsoo Choy, and Li Fei-Fei. Scene graph generation by iterative message passing. 2017 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3097-3106, 2017. 1 +[58] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable $\{\mathrm{detr}\}$ : Deformable transformers for end-to-end object detection. In International Conference on Learning Representations, 2021. 5 \ No newline at end of file diff --git a/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/images.zip b/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..b390f338fdf9119be1867f94994a80bf66a98969 --- /dev/null +++ b/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:ab89c1bd6b8d784ca90a2db86c70646e8d92bab514c8b0308332039d95193fad +size 683545 diff --git a/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/layout.json b/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..9ec94ee290d53941fb7ee34a0f87776390d596a7 --- /dev/null +++ b/2023/MOST_ Multiple Object Localization with Self-Supervised Transformers for Object Discovery/layout.json @@ -0,0 +1,10207 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 67, + 102, + 527, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 102, + 527, + 140 + ], + "spans": [ + { + "bbox": [ + 67, + 102, + 527, + 140 + ], + "type": "text", + "content": "MOST: Multiple Object localization with Self-supervised Transformers for object discovery" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 61, + 160, + 185, + 175 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 160, + 185, + 175 + ], + "spans": [ + { + "bbox": [ + 61, + 160, + 185, + 175 + ], + "type": "text", + "content": "Sai Saketh Rambhatla1,3*" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 75, + 178, + 169, + 187 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 75, + 178, + 169, + 187 + ], + "spans": [ + { + "bbox": [ + 75, + 178, + 169, + 187 + ], + "type": "text", + "content": "rssaketh@meta.com" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 214, + 161, + 276, + 175 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 214, + 161, + 276, + 175 + ], + "spans": [ + { + "bbox": [ + 214, + 161, + 276, + 175 + ], + "type": "text", + "content": "Ishan Misra" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 205, + 178, + 287, + 188 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 205, + 178, + 287, + 188 + ], + "spans": [ + { + "bbox": [ + 205, + 178, + 287, + 188 + ], + "type": "text", + "content": "imisra@meta.com" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 310, + 161, + 402, + 175 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 161, + 402, + 175 + ], + "spans": [ + { + "bbox": [ + 310, + 161, + 402, + 175 + ], + "type": "text", + "content": "Rama Chellappa2,3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 313, + 178, + 400, + 189 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 313, + 178, + 400, + 189 + ], + "spans": [ + { + "bbox": [ + 313, + 178, + 400, + 189 + ], + "type": "text", + "content": "rchella4@jhu.edu" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 426, + 161, + 531, + 175 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 426, + 161, + 531, + 175 + ], + "spans": [ + { + "bbox": [ + 426, + 161, + 531, + 175 + ], + "type": "text", + "content": "Abhinav Shrivastava3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 429, + 178, + 528, + 188 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 429, + 178, + 528, + 188 + ], + "spans": [ + { + "bbox": [ + 429, + 178, + 528, + 188 + ], + "type": "text", + "content": "abhinav@cs.umd.edu" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 111, + 194, + 482, + 210 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 194, + 482, + 210 + ], + "spans": [ + { + "bbox": [ + 111, + 194, + 482, + 210 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 111, + 194, + 482, + 210 + ], + "type": "text", + "content": "Meta " + }, + { + "bbox": [ + 111, + 194, + 482, + 210 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 111, + 194, + 482, + 210 + ], + "type": "text", + "content": "Johns Hopkins University " + }, + { + "bbox": [ + 111, + 194, + 482, + 210 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 111, + 194, + 482, + 210 + ], + "type": "text", + "content": "University of Maryland, College Park" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 143, + 236, + 192, + 249 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 236, + 192, + 249 + ], + "spans": [ + { + "bbox": [ + 143, + 236, + 192, + 249 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 47, + 262, + 290, + 526 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 262, + 290, + 526 + ], + "spans": [ + { + "bbox": [ + 47, + 262, + 290, + 526 + ], + "type": "text", + "content": "We tackle the challenging task of unsupervised object localization in this work. Recently, transformers trained with self-supervised learning have been shown to exhibit object localization properties without being trained for this task. In this work, we present Multiple Object localization with Self-supervised Transformers (MOST) that uses features of transformers trained using self-supervised learning to localize multiple objects in real world images. MOST analyzes the similarity maps of the features using box counting; a fractal analysis tool to identify tokens lying on foreground patches. The identified tokens are then clustered together, and tokens of each cluster are used to generate bounding boxes on foreground regions. Unlike recent state-of-the-art object localization methods, MOST can localize multiple objects per image and outperforms SOTA algorithms on several object localization and discovery benchmarks on PASCAL-VOC 07, 12 and COCO20k datasets. Additionally, we show that MOST can be used for self-supervised pretraining of object detectors, and yields consistent improvements on fully, semi-supervised object detection and unsupervised region proposal generation. Our project is publicly available at rssaketh.github.io/most." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 47, + 552, + 128, + 563 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 552, + 128, + 563 + ], + "spans": [ + { + "bbox": [ + 47, + 552, + 128, + 563 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 46, + 572, + 287, + 693 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 572, + 287, + 693 + ], + "spans": [ + { + "bbox": [ + 46, + 572, + 287, + 693 + ], + "type": "text", + "content": "Object detectors are important components of several computer vision systems such as visual relationship detection [21, 29], human-object interaction detection [1, 13, 45, 52], scene graph generation [57] and object tracking [54, 56] etc. Performance of object detectors is heavily reliant on the availability of training data. However, annotating large object detection datasets can be expensive and time consuming [14, 27]. Additionally, the vocabulary of object detectors is limited by the training datasets and such detectors often fail to generalize to new cate" + } + ] + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 307, + 236, + 386, + 296 + ], + "blocks": [ + { + "bbox": [ + 307, + 236, + 386, + 296 + ], + "lines": [ + { + "bbox": [ + 307, + 236, + 386, + 296 + ], + "spans": [ + { + "bbox": [ + 307, + 236, + 386, + 296 + ], + "type": "image", + "image_path": "61a59c0777062ed682651c552f2444d5158933def8ac3fbb7b3e4ec2d73aaffc.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 387, + 236, + 465, + 296 + ], + "blocks": [ + { + "bbox": [ + 387, + 236, + 465, + 296 + ], + "lines": [ + { + "bbox": [ + 387, + 236, + 465, + 296 + ], + "spans": [ + { + "bbox": [ + 387, + 236, + 465, + 296 + ], + "type": "image", + "image_path": "7f0260f7fe1aa8978cb4d27127c79235e429d9013382d289a53abe253dc87bb7.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 466, + 236, + 545, + 296 + ], + "blocks": [ + { + "bbox": [ + 466, + 236, + 545, + 296 + ], + "lines": [ + { + "bbox": [ + 466, + 236, + 545, + 296 + ], + "spans": [ + { + "bbox": [ + 466, + 236, + 545, + 296 + ], + "type": "image", + "image_path": "023633a71713b03fc570ea1713674f5ad5bdca26457fd2897f6a4d017a80855b.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 307, + 299, + 386, + 358 + ], + "blocks": [ + { + "bbox": [ + 307, + 299, + 386, + 358 + ], + "lines": [ + { + "bbox": [ + 307, + 299, + 386, + 358 + ], + "spans": [ + { + "bbox": [ + 307, + 299, + 386, + 358 + ], + "type": "image", + "image_path": "e64c0686e63d34c8002db11e89b86fc09c06703053cd1d8941d61f72abf61f30.jpg" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 367, + 546, + 428 + ], + "lines": [ + { + "bbox": [ + 305, + 367, + 546, + 428 + ], + "spans": [ + { + "bbox": [ + 305, + 367, + 546, + 428 + ], + "type": "text", + "content": "Figure 1: Top: Methods like LOST [41] (shown in figure), TokenCut [53] identify and localize the most salient foreground object and hence can detect only one object per image. Bottom: MOST is a simple, yet effective method that localizes multiple objects per image without training." + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_caption" + } + ], + "index": 19 + }, + { + "type": "image", + "bbox": [ + 386, + 299, + 465, + 358 + ], + "blocks": [ + { + "bbox": [ + 386, + 299, + 465, + 358 + ], + "lines": [ + { + "bbox": [ + 386, + 299, + 465, + 358 + ], + "spans": [ + { + "bbox": [ + 386, + 299, + 465, + 358 + ], + "type": "image", + "image_path": "e437b7faef62dc1a23f8dfb83d1966fd65a1c3f2b61b8b0d1aee43df4d2f1d54.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + } + ], + "index": 20 + }, + { + "type": "image", + "bbox": [ + 466, + 299, + 545, + 358 + ], + "blocks": [ + { + "bbox": [ + 466, + 299, + 545, + 358 + ], + "lines": [ + { + "bbox": [ + 466, + 299, + 545, + 358 + ], + "spans": [ + { + "bbox": [ + 466, + 299, + 545, + 358 + ], + "type": "image", + "image_path": "5c0d0b1c0e8830ff68619378c9935da75155c2ba484d0460a04c23193bd89993.jpg" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_body" + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 437, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 437, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 437, + 547, + 715 + ], + "type": "text", + "content": "gories [7]. This strategy is not scalable and a more effective approach is warranted. Object discovery is one such task that has the potential to address these concerns. Object discovery is the problem of identifying and grouping objects/parts in a large collection of images without human intervention [23, 24, 36, 43]. The first step in object discovery is to obtain region proposals and subsequently group them semantically. Previous works on discovery used Selective Search [46], randomized Prim's [30] or a region proposal network (RPN) [35] to get object proposals. [48-50] used inter-image similarity to construct a graph and performed optimization or ranking, to localize objects without any supervision. Such methods are computationally expensive and often fail to scale to datasets larger than 20000 images. [34] used region proposals from an RPN and proposed a never ending learning approach and is the first method shown to scale to " + }, + { + "bbox": [ + 304, + 437, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\sim 100000" + }, + { + "bbox": [ + 304, + 437, + 547, + 715 + ], + "type": "text", + "content": " images. However, these region proposal methods are often of low quality, and therefore reduce the performance of discovery systems. Recently, LOST [41] and TokenCut [53] leveraged the object segmentation properties of transformers [47] trained using self-supervised learning (DINO [3]) to obtain high quality object proposals. They demonstrate significant improvements over" + } + ] + } + ], + "index": 23 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 62, + 703, + 149, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 703, + 149, + 712 + ], + "spans": [ + { + "bbox": [ + 62, + 703, + 149, + 712 + ], + "type": "text", + "content": "Work done while at UMD." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15823" + } + ] + } + ], + "index": 25 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 286, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 286, + 95 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 286, + 95 + ], + "type": "text", + "content": "state-of-the-art on object discovery, salient object detection and weakly supervised object localization benchmarks." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 96, + 286, + 215 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 96, + 286, + 215 + ], + "spans": [ + { + "bbox": [ + 46, + 96, + 286, + 215 + ], + "type": "text", + "content": "However, both LOST [41] and TokenCut [53] assume the presence of a single salient object per image and hence, can localize only one object as shown in Fig 1 (top). This assumption may hold for object centric datasets like ImageNet [37] but is not true for scene-centric real world datasets like PASCAL-VOC [12] and COCO [27]. In this work, we address the problem of localizing multiple objects per image and demonstrate the effectiveness of our approach for the task of unsupervised object localization and discovery on several standard benchmarks." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 216, + 287, + 610 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 216, + 287, + 610 + ], + "spans": [ + { + "bbox": [ + 46, + 216, + 287, + 610 + ], + "type": "text", + "content": "We propose a new object localization method called \"Multiple Object localization with Self-supervised Transformers\" (MOST) which is capable of localizing multiple objects per image without using any labels. We use the features extracted from a transformer [47] network trained with DINO [3]. Our method is based on two empirical observations; 1) Patches within foreground objects have higher correlation with each other than the ones on the background [41] and 2) The similarity map computed using the features of a foreground object with all the features in the image is usually more localized and less noisier than the one computed using the feature of a background. Our algorithm analyzes the similarities between patches exhaustively using a fractal analysis tool called box counting [28]. This analysis picks a set of patches that most likely lie on foreground objects. Next, we perform clustering on the patch locations to group patches belonging to a foreground object together. Each of these clusters is called pools. A binary mask is then computed for each pool and a bounding box is extracted. This capability enables the algorithm to extract multiple bounding boxes per image as shown in Fig.1 (bottom). We demonstrate that without any training, our method can outperform state-of-the-art object localization methods that train class agnostic detectors to detect multiple objects. To prove the effectiveness of MOST, we demonstrate results on several object localization and discovery benchmarks. On self-supervised pre-training for object detectors, using MOST yields consistent improvement across multiple downstream tasks using " + }, + { + "bbox": [ + 46, + 216, + 287, + 610 + ], + "type": "inline_equation", + "content": "6 \\times" + }, + { + "bbox": [ + 46, + 216, + 287, + 610 + ], + "type": "text", + "content": " fewer boxes. When compared against other self-supervised transformer-based localization methods, MOST achieves higher recall with and without additional training. We summarize the contributions of our work below." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 59, + 621, + 286, + 712 + ], + "type": "list", + "angle": 0, + "index": 5, + "blocks": [ + { + "bbox": [ + 59, + 621, + 286, + 656 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 621, + 286, + 656 + ], + "spans": [ + { + "bbox": [ + 59, + 621, + 286, + 656 + ], + "type": "text", + "content": "- We propose MOST, an effective method to localize and discover multiple objects per image without supervision using transformers trained with DINO." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 59, + 666, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 666, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 666, + 286, + 712 + ], + "type": "text", + "content": "- We perform exhaustive experiments to assess the performance of MOST on several localization and discovery benchmarks and show significant improvements over the baselines." + } + ] + } + ], + "index": 4 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 305, + 72, + 545, + 131 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 131 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 131 + ], + "type": "text", + "content": "The paper is organized as follows. In Section 2 we discuss related works on object localization and discovery. We describe our approach in detail in Section 3. We describe our experimental setup and present results in Section 4 and conclude in Section 5." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 143, + 397, + 156 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 143, + 397, + 156 + ], + "spans": [ + { + "bbox": [ + 306, + 143, + 397, + 156 + ], + "type": "text", + "content": "2. Related Works" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 163, + 545, + 509 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 163, + 545, + 509 + ], + "spans": [ + { + "bbox": [ + 304, + 163, + 545, + 509 + ], + "type": "text", + "content": "Unsupervised Object Localization and Discovery: Object category discovery can be broadly segregated into image-based [15, 16, 18-20, 42] and region-based methods [4, 8, 22-24, 34, 41, 48-50, 53]. Region-based methods start by generating object proposals and later group them into coherent semantic groups. Image-based approaches on the other hand, assume the localization task to be solved and focus solely on the semantic grouping. Our current method is closer to the former. Vo et al., [48-50] localize regions in images by constructing an inter-image similarity graph between regions and partitioning it using optimization or ranking. Due to the quadratic nature of the graph, these methods cannot scale to large datasets beyond tens of thousands of images. Our current work does not compute inter-image similarity between regions and scales linearly with number of images. Lee et al., [24] propose object graphs that incorporates knowledge about a few known categories to facilitate the discovery of novel categories. MOST doesn't assume any prior knowledge and has the ability to discover objects from scratch. Lee et al., [23] extend object graphs to a curriculum based discovery pipeline, that learns to discover easy objects first and progressively proceeds to discover the harder ones. Along similar lines, Rambhatla et al., [34] propose a large scale discovery pipeline, similar to [24] that leverages prior knowledge about a few categories. Authors of [34] use an RPN [35] trained on known categories as the localization method. In contrast to that, MOST localizes objects in images using features of a transformer [47] trained with DINO [3]." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 510, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 510, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 545, + 713 + ], + "type": "text", + "content": "Object localization using self-supervised networks: Recently, CNNs [17] and Transformers [47] trained in a self-supervised fashion, have been shown to exhibit object localization/segmentation properties [3, 10]. This property is of particular interest as it has the potential to facilitate research on unsupervised localization, detection and segmentation. [41] is a simple method, based on the observation that the key features of the last self attention layer of a transformer, trained using DINO, has certain affinity. They construct a map of inverse degree to extract bounding boxes on objects in an unsupervised fashion. This method is shown to outperform recent state-of-the-art methods by a significant margin. [53] propose an alternate method for localizing objects using self-supervised transformers, based on normalized cut [39]. TokenCut [53] construct an undirected graph based on token feature similarities and use normalized cut to cluster foreground and background patches. SpectralCLUS" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "15824" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 48, + 75, + 287, + 122 + ], + "blocks": [ + { + "bbox": [ + 48, + 75, + 287, + 122 + ], + "lines": [ + { + "bbox": [ + 48, + 75, + 287, + 122 + ], + "spans": [ + { + "bbox": [ + 48, + 75, + 287, + 122 + ], + "type": "image", + "image_path": "ca286425971646cacee15f3b712ebf7dc91a261928ce96dc1b494574704b62a4.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 129, + 288, + 178 + ], + "lines": [ + { + "bbox": [ + 46, + 129, + 288, + 178 + ], + "spans": [ + { + "bbox": [ + 46, + 129, + 288, + 178 + ], + "type": "text", + "content": "Figure 2: Motivation for MOST: Example showing similarity maps of tokens within background and foreground for an image from the COCO dataset. Similarity maps of tokens within foreground patches are less random spatially." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 199, + 287, + 342 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 199, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 46, + 199, + 287, + 342 + ], + "type": "text", + "content": "tering is used to solve the graph-cut and they show that the eigen vector corresponding to the second smallest eigenvalue provides a good cutting solution. TokenCut outperforms LOST on unsupervised object discovery. In addition to discovery, [53] also demonstrate impressive results on unsupervised saliency detection and weakly supervised object localization. Kyriazi et al., [31] propose deep spectral methods, that performs normalized cut [39] but using an affinity matrix computed using semantic and color features. Since this method is very similar to TokenCut and achieves lower performance, we only compare with the latter in this work." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 342, + 287, + 403 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 342, + 287, + 403 + ], + "spans": [ + { + "bbox": [ + 46, + 342, + 287, + 403 + ], + "type": "text", + "content": "However, one limitation of LOST and TokenCut is that they can localize only one object per image. Our proposed method, MOST can automatically localize multiple objects per image and outperforms LOST and TokenCut on standard discovery benchmarks." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 415, + 156, + 428 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 415, + 156, + 428 + ], + "spans": [ + { + "bbox": [ + 47, + 415, + 156, + 428 + ], + "type": "text", + "content": "3. Approach: MOST" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 434, + 287, + 519 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 434, + 287, + 519 + ], + "spans": [ + { + "bbox": [ + 46, + 434, + 287, + 519 + ], + "type": "text", + "content": "MOST can be used to localize multiple objects in an image. Our approach, illustrated in Fig. 3, first identifies a set of tokens that is computed from patches on foreground objects. These tokens are then clustered and each cluster, named pool, is used to obtain a bounding box. Next, we discuss a few preliminaries in Section 3.1 followed by the motivation and proposed solution in Section 3.2." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 527, + 133, + 538 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 527, + 133, + 538 + ], + "spans": [ + { + "bbox": [ + 47, + 527, + 133, + 538 + ], + "type": "text", + "content": "3.1. Preliminaries" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 545, + 287, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 545, + 287, + 604 + ], + "spans": [ + { + "bbox": [ + 46, + 545, + 287, + 604 + ], + "type": "text", + "content": "Box Counting: Box counting is a method of analyzing a pattern by breaking and analyzing it at smaller scales. This is done by performing a raster scan of the pattern at different scales and computing appropriate metrics to assess its fractal nature. In this work, we use a sliding window scan." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "content": "Vision Transformers: ViTs [9] operate on learned embeddings, called tokens, generated from non-overlapping image patches of resolution " + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mathrm{P} \\times \\mathrm{P}" + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "content": " (typically " + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mathrm{P} = 8 / 16" + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "content": ") that form a sequence. To be precise, an image " + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mathrm{I}" + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "content": " of shape " + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "inline_equation", + "content": "H \\times W \\times 3" + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "content": " is first divided into non-overlapping patches of resolution " + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "inline_equation", + "content": "P \\times P \\times 3" + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "content": ", generating a total of " + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mathrm{N} = HW / P^2" + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "content": " patches. Next, each patch is embedded via a trainable linear layer to generate a token of dimension " + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "content": " to form a sequence of patches. An extra [CLS] token [6] is added to this sequence, whose" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 72, + 545, + 107 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 107 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 107 + ], + "type": "text", + "content": "purpose is to aggregate the information from the tokens of the sequence. Typically, a projection head is attached to the [CLS] to train the network for classification." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 108, + 546, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 108, + 546, + 361 + ], + "spans": [ + { + "bbox": [ + 304, + 108, + 546, + 361 + ], + "type": "text", + "content": "DINO: DINO [3] combines self-training and knowledge distillation without labels for self supervised learning. DINO constructs two global views and several local views of lower resolution, from an image. DINO consists of a teacher and a student network. The student processes all the crops while the teacher is operated only on the global crops. The teacher network then distills its dark knowledge to the student. This encourages the student network to learn local to global correspondences. In contrast to other knowledge distillation methods, DINO's teacher network is updated dynamically during training using exponential moving average. DINO was shown to perform on par or better than several baselines on several tasks of image retrieval, copy detection, instance segmentation etc. The property of importance to the current work, is the ability of DINO to localize foreground regions of semantic entities in an image. [41, 53] leverage this property to localize the salient object in an image by using the key features from the last self-attention layer. Similar to [41, 53], we concatenate the key features of all the heads in the last self-attention layer to obtain the input to MOST." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 369, + 457, + 382 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 369, + 457, + 382 + ], + "spans": [ + { + "bbox": [ + 305, + 369, + 457, + 382 + ], + "type": "text", + "content": "3.2. Multiple object localization" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 388, + 545, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 388, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 304, + 388, + 545, + 555 + ], + "type": "text", + "content": "Motivation: Consider the example shown in Fig. 2. We show three examples of the similarity maps of a token (shown in red) picked on the background (column 2) and foreground (columns 3, 4). Tokens within foreground patches have higher correlation than the ones on background [41]. This results in the similarity maps of foreground patches being less \"spatially\" random than the ones on the background. The task then becomes to analyze the similarity maps and identify the ones with less spatial randomness. Box counting [25, 33] is a popular technique in fractal analysis that analyzes spatial patterns at different scales to extract desired properties. Hence, we adopt box counting for our case and since, we are interested in randomness, we adopt entropy as the metric." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "content": "Preprocessing: The input to our method is a " + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "content": "-dimensional feature " + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "inline_equation", + "content": "F \\in \\mathbb{R}^{N \\times d}" + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "content": ", extracted from an image using a neural network. Here, " + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "content": " denotes the number of spatial locations in the feature map, in case of a CNN, or number of tokens, in case of a transformer network. The aim is to identify subsets of tokens, which we call pools, that can be used to localize all the objects in an image. We do not make any assumption on the number of objects present in the image. Given the feature " + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "content": ", we compute an outer product matrix " + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "inline_equation", + "content": "A = F F^T \\in \\mathbb{R}^{N \\times N}" + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "content": ". Row " + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "content": " of matrix " + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "inline_equation", + "content": "A" + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "content": ", i.e., " + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "inline_equation", + "content": "A[i,:]" + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "content": " encodes a similarity map of a token at location " + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "content": " with all the other tokens in " + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "content": ". Next, each row of " + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "inline_equation", + "content": "A" + }, + { + "bbox": [ + 304, + 556, + 546, + 713 + ], + "type": "text", + "content": " is processed by the Entropy-based Box Analysis (EBA) module." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15825" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 73, + 547, + 300 + ], + "blocks": [ + { + "bbox": [ + 50, + 73, + 547, + 300 + ], + "lines": [ + { + "bbox": [ + 50, + 73, + 547, + 300 + ], + "spans": [ + { + "bbox": [ + 50, + 73, + 547, + 300 + ], + "type": "image", + "image_path": "a49e5e55d52837e112a80d00c3e228f880c9ae639797a84ed13c7b4b3663f899.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 311, + 546, + 361 + ], + "lines": [ + { + "bbox": [ + 45, + 311, + 546, + 361 + ], + "spans": [ + { + "bbox": [ + 45, + 311, + 546, + 361 + ], + "type": "text", + "content": "Figure 3: Overview of MOST: MOST operates on features extracted from transformers trained using DINO. The features are used to compute the outer product " + }, + { + "bbox": [ + 45, + 311, + 546, + 361 + ], + "type": "inline_equation", + "content": "A" + }, + { + "bbox": [ + 45, + 311, + 546, + 361 + ], + "type": "text", + "content": ". Each row of " + }, + { + "bbox": [ + 45, + 311, + 546, + 361 + ], + "type": "inline_equation", + "content": "A" + }, + { + "bbox": [ + 45, + 311, + 546, + 361 + ], + "type": "text", + "content": " is analyzed by the entropy-based box analysis (EBA) module that identifies tokens extracted from foreground patches. These patches are clustered using spatial locations as features to form pools. Each pool is then post-processed to generate a bounding box." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": "Entropy-based Box Analysis (EBA): The proposed entropy based box analysis module performs a fractal analysis method, called box counting to segregate similarity maps of tokens on foreground patches from those of background. As shown in Fig. 3, we perform a raster scan with increasing box (used interchangeably with kernel in this work) sizes on each map. Traditionally, measures like lacunarity [44] are computed within each box to analyze the pattern. In this work, we average the elements within each box. This can be implemented efficiently using pooling operations. The resulting downsampled map is flattened and the entropy is computed using the pmf computed as follows: " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "p(x = x_{i}) = \\sum_{i = 1}^{h.w}\\frac{\\mathbb{1}(f_{i} == x_{i})}{h.w}" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "f_{i}" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": " is the " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "i^{\\text{th}}" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": " index in the feature map. A downsampled map belongs to a token on a foreground patch if its entropy is less than a threshold " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": ". Using " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": " boxes in the EBA module results in " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": " entropy values " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "e_k(k\\in \\{1,2,\\dots ,K\\})" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": ". Finally, we perform a majority voting among the entropies of all the downsampled maps, i.e., " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "\\sum_{i = 1}^{K}\\frac{\\mathbb{1}(e_i\\leq\\tau)}{K} >0.5" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": ", to decide if the original similarity map belongs to a token on a foreground patch. A map of dimension " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "n\\times n" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": " has a maximum entropy of " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "log(n^{2})" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": ". We use a threshold of the form " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "\\tau = a + blog(n^{2})" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": " (we use " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "a = 1,b = 0.5" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": " in this work). We do not consider " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": " as a hyperparameter and we pick a value that is mid-way between the minimum and maximum permissible value " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "(b = 0.5)" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": ". To prevent a threshold of 0 for " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "n = 1" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": ", we add a constant " + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "inline_equation", + "content": "(a = 1)" + }, + { + "bbox": [ + 46, + 380, + 289, + 696 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 700, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 700, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 700, + 287, + 715 + ], + "type": "text", + "content": "Clustering: The EBA module, identifies a set " + }, + { + "bbox": [ + 47, + 700, + 287, + 715 + ], + "type": "inline_equation", + "content": "S = \\{p|p\\in" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 304, + 380, + 545, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 380, + 545, + 536 + ], + "spans": [ + { + "bbox": [ + 304, + 380, + 545, + 536 + ], + "type": "inline_equation", + "content": "\\{1,2,\\dots ,N\\}\\}" + }, + { + "bbox": [ + 304, + 380, + 545, + 536 + ], + "type": "text", + "content": ", that contains the spatial locations of tokens computed from foreground patches. Often, highly redundant neighboring tokens are identified. We group neighboring tokens with the help of a clustering step to obtain pools. We convert the linear index " + }, + { + "bbox": [ + 304, + 380, + 545, + 536 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 304, + 380, + 545, + 536 + ], + "type": "text", + "content": " of the tokens to cartesian coordinates " + }, + { + "bbox": [ + 304, + 380, + 545, + 536 + ], + "type": "inline_equation", + "content": "(x,y)" + }, + { + "bbox": [ + 304, + 380, + 545, + 536 + ], + "type": "text", + "content": ", and use that as the feature for clustering. Manhattan distance is used as the dissimilarity metric with a threshold " + }, + { + "bbox": [ + 304, + 380, + 545, + 536 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 304, + 380, + 545, + 536 + ], + "type": "text", + "content": " (" + }, + { + "bbox": [ + 304, + 380, + 545, + 536 + ], + "type": "inline_equation", + "content": "\\epsilon = 2" + }, + { + "bbox": [ + 304, + 380, + 545, + 536 + ], + "type": "text", + "content": " i.e. Moore neighborhood). Since, the number of pools is not known a-priori, we use a density-based clustering method, DBSCAN [11] which automatically identifies the number of clusters from the data. Pools identified by the clustering step are then post-processed to obtain bounding boxes on foreground objects." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "spans": [ + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "text", + "content": "Post-processing: The clusters, called pools, obtained from the clustering step are then post-processed to obtain one box per pool. Consider " + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "text", + "content": " pools identified by the clustering step, i.e. " + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_i" + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "inline_equation", + "content": "i \\in \\{1,2,\\dots M\\}" + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "text", + "content": ". Each pool " + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_i" + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "text", + "content": " is a set of token locations " + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_i = \\{p^i | p^i \\in \\{1,2,\\dots ,N\\}\\}" + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "text", + "content": ". We leverage the first observation mentioned above to obtain a bounding box from the pool as follows. First, we build a binary similarity matrix " + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "inline_equation", + "content": "\\hat{A} = A > 0" + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "text", + "content": ". Next, within the tokens in the pool, we identify the one with lowest degree in " + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "inline_equation", + "content": "\\hat{A}" + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "text", + "content": ", called the core token, " + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "inline_equation", + "content": "c^*" + }, + { + "bbox": [ + 304, + 536, + 546, + 656 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 335, + 662, + 515, + 696 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 335, + 662, + 515, + 696 + ], + "spans": [ + { + "bbox": [ + 335, + 662, + 515, + 696 + ], + "type": "interline_equation", + "content": "c ^ {*} = \\underset {c \\in \\mathcal {C} _ {i}} {\\arg \\min } d _ {c} \\quad \\text {w h e r e} \\quad d _ {c} = \\sum_ {j = 1} ^ {N} \\hat {A} [ c, j ]", + "image_path": "63712a1ef7981f64d463b293eeebe850a18577b5e6b26308eac4150095c5296a.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 701, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 701, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 306, + 701, + 545, + 714 + ], + "type": "text", + "content": "Authors of LOST [41] report that tokens with low degrees" + } + ] + } + ], + "index": 7 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15826" + } + ] + } + ], + "index": 8 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 127, + 547, + 269 + ], + "blocks": [ + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "lines": [ + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "text", + "content": "Table 1: Results on unsupervised pre-training of object detectors. We train object detectors in a self-supervised fashion on the COCO dataset using different localization methods and compare their performance on the downstream tasks of semi and fully supervised object detection. COCO train set is used for fine-tuning and " + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "inline_equation", + "content": "k\\%" + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "text", + "content": " refers to the number of labeled samples used for training. Results are reported using AP[0.50:0.95] (denoted as AP), " + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "inline_equation", + "content": "{\\mathrm{{AP}}}_{0.50}" + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "text", + "content": " ,and " + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "inline_equation", + "content": "{\\mathrm{{AP}}}_{0.75}" + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "text", + "content": " on COCO validation set." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 127, + 547, + 269 + ], + "lines": [ + { + "bbox": [ + 48, + 127, + 547, + 269 + ], + "spans": [ + { + "bbox": [ + 48, + 127, + 547, + 269 + ], + "type": "table", + "html": "
MethodBoxes per imageVOC 07+12COCO
k=10%fully supervisedk=1%k=2%k=5%fully supervised
APAP50AP75APAP50AP75APAPAP50
LOST [41]140.8860.3144.3663.5883.2770.4812.83 ± 0.3217.23 ± 0.3023.43 ± 0.3844.3062.80
TCut [53]141.1460.5944.3563.7983.5670.7013.13 ± 0.3817.27 ± 0.2123.27 ± 0.2343.8062.30
539.1257.5142.2963.4483.1470.3513.57 ± 0.3817.87 ± 0.3223.17 ± 0.4044.3062.80
SS [46]1040.7660.0044.4664.2383.4471.5513.73 ± 0.2918.00 ± 0.2622.83 ± 0.2543.9062.60
1542.1461.4145.8664.2483.7471.4113.87 ± 0.2918.23 ± 0.4023.13 ± 0.1144.3062.60
MOST4.6543.0363.2946.6164.3484.1271.7713.93 ± 0.3818.13 ± 0.2522.63 ± 0.1144.8063.50
SS3042.1261.2045.7164.8483.9871.7614.47 ± 0.3518.23 ± 0.4223.57 ± 0.2144.0062.30
MOST13.0944.4063.8348.2865.2484.2472.3714.83 ± 0.2118.30 ± 0.1723.43 ± 0.4545.2064.00
", + "image_path": "56e0b5a82b1a077776689ee6e42d4dd46cdb4761d700252291b451568006e5e2.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "spans": [ + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "text", + "content": "most likely fall within an object. Next, we remove the tokens from the pool that do not correlate positively with " + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "inline_equation", + "content": "c^*" + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "text", + "content": " to form a reduced pool " + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_i^*" + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "text", + "content": ". This ensures that all the tokens in the current pool lie on the same foreground object. Next, a binary mask is constructed by computing the sum of similarities of token features in " + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_i^*" + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "text", + "content": " with the features of all the tokens, i.e. " + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "inline_equation", + "content": "m_k^i = 11(\\sum_{c\\in \\mathcal{C}_i^*}f_k^T f_c\\geq 0)" + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "text", + "content": ". Finally, connected component analysis is performed on the binary mask and the bounding box of the island that contains " + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "inline_equation", + "content": "c^*" + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "text", + "content": " is selected as the region containing the object. We repeat this process for all the " + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "text", + "content": " pools to generate " + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "text", + "content": " bounding boxes per image. Note that, " + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 46, + 289, + 289, + 469 + ], + "type": "text", + "content": " is not assumed to be known a-priori and is decided automatically by our method. Additionally, we remove trivial boxes i.e., boxes which have area less than than a threshold (256) or cover the whole image." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 469, + 289, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 469, + 289, + 529 + ], + "spans": [ + { + "bbox": [ + 46, + 469, + 289, + 529 + ], + "type": "text", + "content": "Implementation Details: For all our experiments, we use the ViT-S/16 and ViT-B/8 [9] models trained with DINO [3] to extract the features. We concatenate the key features of all the heads from the last self-attention layer to use as the input to our method." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 537, + 128, + 552 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 537, + 128, + 552 + ], + "spans": [ + { + "bbox": [ + 47, + 537, + 128, + 552 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 558, + 287, + 654 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 558, + 287, + 654 + ], + "spans": [ + { + "bbox": [ + 46, + 558, + 287, + 654 + ], + "type": "text", + "content": "In this section we describe, in detail, the experimental setup used for evaluation. We evaluate our method on two setups, namely the localization setup, and the discovery setup. We begin by describing the datasets and metrics in Sec. 4.1. We describe the evaluation setups in Sec. 4.2. Sec. 4.3 compares our method against contemporary work. We then describe ablation experiments in Sec. 4.4 and show qualitative results in Sec. 4.6." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 659, + 169, + 671 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 659, + 169, + 671 + ], + "spans": [ + { + "bbox": [ + 47, + 659, + 169, + 671 + ], + "type": "text", + "content": "4.1. Datasets and Metrics" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "content": "We use the PASCAL-VOC [12] (2007, 2012 splits) and the COCO [27] (COCO20k [49] and COCO splits) datasets in our experiments. The PASCAL VOC [12] 2007 and 2012" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 289, + 545, + 372 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 289, + 545, + 372 + ], + "spans": [ + { + "bbox": [ + 304, + 289, + 545, + 372 + ], + "type": "text", + "content": "trainval sets consists of 5011, 11540 images respectively, spanning twenty objects. The PASCAL VOC [12] test set consists of 4952 images. The COCO [27] 2014 train set consists of " + }, + { + "bbox": [ + 304, + 289, + 545, + 372 + ], + "type": "inline_equation", + "content": "\\sim 110\\mathrm{k}" + }, + { + "bbox": [ + 304, + 289, + 545, + 372 + ], + "type": "text", + "content": " images containing over eighty objects and the COCO minimal set consists of 5000 images. We do not use any class or bounding box annotations for our method except for evaluation." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 373, + 546, + 506 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 373, + 546, + 506 + ], + "spans": [ + { + "bbox": [ + 304, + 373, + 546, + 506 + ], + "type": "text", + "content": "For the localization setup, we use the average precision at different thresholds ([0.5:0.95], 0.5 and 0.75), average recall (AR1, AR10 and AR100) and Correct Localization (CorLoc) metrics for evaluation. CorLoc is defined as the fraction of the images in which atleast one object is localized with an IoU greater than a threshold (0.5 in this work). AP, AR are defined in the usual way. For the object discovery setup, we report both the PASCAL VOC style " + }, + { + "bbox": [ + 304, + 373, + 546, + 506 + ], + "type": "inline_equation", + "content": "\\mathrm{AP}_{50}" + }, + { + "bbox": [ + 304, + 373, + 546, + 506 + ], + "type": "text", + "content": " and COCO style " + }, + { + "bbox": [ + 304, + 373, + 546, + 506 + ], + "type": "inline_equation", + "content": "\\mathrm{AP}_{[50:95]}" + }, + { + "bbox": [ + 304, + 373, + 546, + 506 + ], + "type": "text", + "content": " metrics along with area under the purity-coverage plots [8, 34]. We refer the interested readers to [34] for definitions of purity and coverage." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 515, + 360, + 528 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 515, + 360, + 528 + ], + "spans": [ + { + "bbox": [ + 306, + 515, + 360, + 528 + ], + "type": "text", + "content": "4.2. Setups" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 534, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 534, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 534, + 547, + 713 + ], + "type": "text", + "content": "Localization setup: This setup evaluates the localization performance of methods. We evaluate models on a) unsupervised pre-training, b) Multiple Object Localization, and c) single object localization. For unsupervised pre-training, localization methods are used to train object detectors in an unsupervised fashion and their performance is evaluated on the downstream task of object detection. In this work, we use the recently proposed DETReg [2] as the pre-training strategy which uses a Deformable DeTR [58] architecture. DETReg uses an object localization method and pre-trains an object detector in an unsupervised fashion. We evaluate the pre-trained model on the downstream tasks of semi-supervised, fully-supervised and class-agnostic object proposal generation. In the semi-supervised setting, models are trained on the PASCAL-VOC(07+12) and COCO train" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15827" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 140, + 198, + 229 + ], + "blocks": [ + { + "bbox": [ + 47, + 70, + 200, + 131 + ], + "lines": [ + { + "bbox": [ + 47, + 70, + 200, + 131 + ], + "spans": [ + { + "bbox": [ + 47, + 70, + 200, + 131 + ], + "type": "text", + "content": "Table 2: Unsupervised class agnostic region proposal evaluation on COCO validation set: We compare the performance of region proposals for training DETReg. " + }, + { + "bbox": [ + 47, + 70, + 200, + 131 + ], + "type": "inline_equation", + "content": "Rk" + }, + { + "bbox": [ + 47, + 70, + 200, + 131 + ], + "type": "text", + "content": " is Recall@k" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 140, + 198, + 229 + ], + "lines": [ + { + "bbox": [ + 48, + 140, + 198, + 229 + ], + "spans": [ + { + "bbox": [ + 48, + 140, + 198, + 229 + ], + "type": "table", + "html": "
MethodBoxes per imageAP\\( AP_{50} \\)\\( AP_{75} \\)R1R10R100
LOST [41]10.10.500.41.43.9
TCut [53]10.310.10.61.94.6
50.10.400.114.2
SS [46]100.10.300.11.14.4
150.10.300.114.1
300.10.300.114
MOST4.650.81.410.61.94.4
", + "image_path": "afdd52ed53c2d2404717beab416e7d6db01d1a03ea004ac65559762877a6e973.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "table", + "bbox": [ + 207, + 140, + 401, + 229 + ], + "blocks": [ + { + "bbox": [ + 205, + 70, + 403, + 130 + ], + "lines": [ + { + "bbox": [ + 205, + 70, + 403, + 130 + ], + "spans": [ + { + "bbox": [ + 205, + 70, + 403, + 130 + ], + "type": "text", + "content": "Table 3: Results on object discovery: Comparison of MOST with recent works on unsupervised object discovery. We experiment with three cluster numbers, i.e., 20, 30, 40, on VOC 2007, 2007+12 and 80, 90, 100 on COCO20k." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 207, + 140, + 401, + 229 + ], + "lines": [ + { + "bbox": [ + 207, + 140, + 401, + 229 + ], + "spans": [ + { + "bbox": [ + 207, + 140, + 401, + 229 + ], + "type": "table", + "html": "
Metric Train →VOC 2007VOC 07+12COCO20k
Clusters →2030402030408090100
APLOST [41]9.159.6410.1110.9512.1412.972.662.912.86
MOST9.2010.0711.0910.1212.8913.303.133.183.32
AP50LOST [41]26.3227.7829.4629.3533.2734.807.177.727.87
MOST25.3528.1931.3127.0434.4034.548.138.148.76
", + "image_path": "1a49bd21a5e8010426acf916d24196cd0327a75cc750ec1ff51d77c72436aa87.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_body" + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 410, + 140, + 550, + 229 + ], + "blocks": [ + { + "bbox": [ + 408, + 71, + 552, + 131 + ], + "lines": [ + { + "bbox": [ + 408, + 71, + 552, + 131 + ], + "spans": [ + { + "bbox": [ + 408, + 71, + 552, + 131 + ], + "type": "text", + "content": "Table 4: Results on single-object localization: Comparison of MOST with recent object discovery methods on VOC 07, 12 and COCO20k using CorLoc." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 410, + 140, + 550, + 229 + ], + "lines": [ + { + "bbox": [ + 410, + 140, + 550, + 229 + ], + "spans": [ + { + "bbox": [ + 410, + 140, + 550, + 229 + ], + "type": "table", + "html": "
MethodVOC 07VOC 12COCO20k
rOSD [49]54.555.348.5
LOD [50]53.655.148.5
DINO-seg† [3]45.846.242.1
LOST [41]61.964.050.7
TokenCut [53]68.872.158.8
LOST [41] + CAD65.770.457.5
TCut [53]+CAD71.475.362.6
MOST74.877.467.1
", + "image_path": "2ebb2890ec69d5b0157a5bb3503b1c4c941c45417cfb4fe10fb8b72e2f27fb27.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 249, + 287, + 332 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 249, + 287, + 332 + ], + "spans": [ + { + "bbox": [ + 45, + 249, + 287, + 332 + ], + "type": "text", + "content": "sets without labels and are fine-tuned on " + }, + { + "bbox": [ + 45, + 249, + 287, + 332 + ], + "type": "inline_equation", + "content": "k\\%" + }, + { + "bbox": [ + 45, + 249, + 287, + 332 + ], + "type": "text", + "content": " of labeled data similar to [2]. In the fully supervised setting, pre-trained models are fine-tuned on the full PASCAL-VOC and COCO dataset using all the labels. For the class-agnostic object proposal generation, models are pre-trained on COCO dataset without labels and the generated object proposals are evaluated on the COCO validation set similar to [2]." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 333, + 287, + 392 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 333, + 287, + 392 + ], + "spans": [ + { + "bbox": [ + 46, + 333, + 287, + 392 + ], + "type": "text", + "content": "We follow the settings used in [50] for multiple-object localization and evaluate on PASCAL-VOC 2007 and COCO20k. For single-object localization, we follow the settings in [41, 53] and evaluate on PASCAL-VOC 2007, PASCAL-VOC 2012 and COCO20k." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 45, + 393, + 288, + 513 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 393, + 288, + 513 + ], + "spans": [ + { + "bbox": [ + 45, + 393, + 288, + 513 + ], + "type": "text", + "content": "Discovery setup: This setup evaluates the object discovery performance. Similar to [41] we use the regions obtained by our localization method, to perform K-means clustering and use the resulting cluster labels to train Faster-RCNN object detectors on PASCAL-VOC 2007, 2012 trainval and COCO20k train sets. We report results of these experiments on the PASCAL-VOC 2007 test and COCO minival sets respectively. In addition to this, we report the performance of our discovery method on COCO train set, similar to the large scale discovery in [34]." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 518, + 263, + 532 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 518, + 263, + 532 + ], + "spans": [ + { + "bbox": [ + 47, + 518, + 263, + 532 + ], + "type": "text", + "content": "4.3. Comparison with contemporary methods" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 537, + 287, + 562 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 537, + 287, + 562 + ], + "spans": [ + { + "bbox": [ + 46, + 537, + 287, + 562 + ], + "type": "text", + "content": "In this section we compare our method against contemporary works the localization and discovery setups." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 574, + 159, + 588 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 574, + 159, + 588 + ], + "spans": [ + { + "bbox": [ + 46, + 574, + 159, + 588 + ], + "type": "text", + "content": "4.3.1 Localization setup" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 45, + 594, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 594, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 45, + 594, + 289, + 715 + ], + "type": "text", + "content": "Unsupervised Pre-training: Table 1 compares the results of all the localization methods on unsupervised pre-training of object detectors. We use average precision at different IoU thresholds ([0.50:0.95]: AP, 0.5: " + }, + { + "bbox": [ + 45, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathrm{AP}_{0.50}" + }, + { + "bbox": [ + 45, + 594, + 289, + 715 + ], + "type": "text", + "content": ", 0.75: " + }, + { + "bbox": [ + 45, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathrm{AP}_{0.75}" + }, + { + "bbox": [ + 45, + 594, + 289, + 715 + ], + "type": "text", + "content": ") for evaluation. On the semi-supervised setting, on VOC " + }, + { + "bbox": [ + 45, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "07 + 12" + }, + { + "bbox": [ + 45, + 594, + 289, + 715 + ], + "type": "text", + "content": " (" + }, + { + "bbox": [ + 45, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "k = 10\\%" + }, + { + "bbox": [ + 45, + 594, + 289, + 715 + ], + "type": "text", + "content": "), the self-supervised transformer based methods (LOST, TokenCut and MOST) outperform SS [46] with fewer boxes per image. In particular, TokenCut (denoted as TCut in Table 1) which outputs only one box per image, outperforms SS, using ten boxes per image, by " + }, + { + "bbox": [ + 45, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\sim 0.4" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "spans": [ + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "text", + "content": "points on mAP. MOST which outputs an average of 4.65 boxes per image outperforms TokenCut (the best performing self-supervised transformer based method) by 1.89, 2.7 and 2.26 percentage points on AP, " + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "inline_equation", + "content": "\\mathrm{AP}_{50}" + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "inline_equation", + "content": "\\mathrm{AP}_{75}" + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "text", + "content": " respectively. This can be attributed to the ability of MOST to output multiple foreground regions resulting in more samples for pre-training which is not possible in the case of TokenCut. MOST outperforms SS, that outputs 30 boxes per image, by 0.91, 2.09 and 0.9 points on AP, " + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "inline_equation", + "content": "\\mathrm{AP}_{50}" + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "inline_equation", + "content": "\\mathrm{AP}_{75}" + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "text", + "content": " respectively using almost " + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "inline_equation", + "content": "6\\times" + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "text", + "content": " fewer boxes per image and this can be attributed to the ability of MOST to generate high quality proposals. On COCO, MOST outperforms TokenCut by 0.8 and 0.86 on the " + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "inline_equation", + "content": "1\\%" + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "inline_equation", + "content": "2\\%" + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "text", + "content": " setting of semi-supervised learning. MOST with a ViT-B/8 backbone, that outputs 13.09 boxes on average per image, outperforms SS (with 30 boxes per image) by 0.36, 0.07 points on " + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "inline_equation", + "content": "k = 1\\%" + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "inline_equation", + "content": "k = 2\\%" + }, + { + "bbox": [ + 304, + 249, + 547, + 453 + ], + "type": "text", + "content": " few shot splits of COCO respectively." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 457, + 547, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 457, + 547, + 555 + ], + "spans": [ + { + "bbox": [ + 304, + 457, + 547, + 555 + ], + "type": "text", + "content": "On the fully supervised setting, MOST outperforms LOST and TokenCut by 0.76 and 0.55 (AP) percentage points respectively on VOC 07+12. On COCO, MOST outperforms them by 0.50 and 1 points respectively. On VOC 07+12, MOST using ViT-B/8 (13.09 boxes per image) outperforms SS (with 30 boxes per image) by 0.40. On the much harder COCO dataset, MOST outperforms SS 1.20 (AP) percentage points using " + }, + { + "bbox": [ + 304, + 457, + 547, + 555 + ], + "type": "inline_equation", + "content": "2 \\times" + }, + { + "bbox": [ + 304, + 457, + 547, + 555 + ], + "type": "text", + "content": " fewer boxes per image." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 558, + 548, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 548, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 548, + 714 + ], + "type": "text", + "content": "In Table 2 we report the class agnostic object proposal evaluation of DETReg trained using different localization methods. We report average precision at different IoU thresholds (AP, " + }, + { + "bbox": [ + 304, + 558, + 548, + 714 + ], + "type": "inline_equation", + "content": "\\mathrm{AP}_{50}" + }, + { + "bbox": [ + 304, + 558, + 548, + 714 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 558, + 548, + 714 + ], + "type": "inline_equation", + "content": "\\mathrm{AP}_{75}" + }, + { + "bbox": [ + 304, + 558, + 548, + 714 + ], + "type": "text", + "content": ") and recall @ 1, 10 and 100 proposals per image (denoted as R1, R10, and R100) to evaluate the quality of region proposals. Note that the numbers in the table are low because of the unsupervised nature of training. All the self-supervised transformer-based methods achieve performance better than SS with far fewer boxes. In recall, TokenCut and MOST perform on par with each other and outperform rest of the methods with significant improvements. MOST achieves the highest performance on average precision among all the methods. It can achieve" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "15828" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 70, + 130, + 121 + ], + "blocks": [ + { + "bbox": [ + 49, + 70, + 130, + 121 + ], + "lines": [ + { + "bbox": [ + 49, + 70, + 130, + 121 + ], + "spans": [ + { + "bbox": [ + 49, + 70, + 130, + 121 + ], + "type": "image", + "image_path": "1812c514a3ca58d091197293527d3af10209491e8a4512da568b8e75248587b2.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 84, + 123, + 94, + 129 + ], + "lines": [ + { + "bbox": [ + 84, + 123, + 94, + 129 + ], + "spans": [ + { + "bbox": [ + 84, + 123, + 94, + 129 + ], + "type": "text", + "content": "k=1" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 132, + 70, + 214, + 121 + ], + "blocks": [ + { + "bbox": [ + 132, + 70, + 214, + 121 + ], + "lines": [ + { + "bbox": [ + 132, + 70, + 214, + 121 + ], + "spans": [ + { + "bbox": [ + 132, + 70, + 214, + 121 + ], + "type": "image", + "image_path": "5cef825af556d0688bd363a529c893966dc46af3dc0c484aea1fb9feaf41ee01.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 167, + 123, + 178, + 129 + ], + "lines": [ + { + "bbox": [ + 167, + 123, + 178, + 129 + ], + "spans": [ + { + "bbox": [ + 167, + 123, + 178, + 129 + ], + "type": "text", + "content": "k=3" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 215, + 70, + 298, + 121 + ], + "blocks": [ + { + "bbox": [ + 215, + 70, + 298, + 121 + ], + "lines": [ + { + "bbox": [ + 215, + 70, + 298, + 121 + ], + "spans": [ + { + "bbox": [ + 215, + 70, + 298, + 121 + ], + "type": "image", + "image_path": "becec42406bb0a5294841aa92dfa23a4be362abcfec37a51051330d13912d091.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 250, + 123, + 261, + 129 + ], + "lines": [ + { + "bbox": [ + 250, + 123, + 261, + 129 + ], + "spans": [ + { + "bbox": [ + 250, + 123, + 261, + 129 + ], + "type": "text", + "content": "k=5" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 49, + 134, + 130, + 192 + ], + "blocks": [ + { + "bbox": [ + 49, + 134, + 130, + 192 + ], + "lines": [ + { + "bbox": [ + 49, + 134, + 130, + 192 + ], + "spans": [ + { + "bbox": [ + 49, + 134, + 130, + 192 + ], + "type": "image", + "image_path": "6b54989c587365291834c1b104435a165a3e025e14a4e77453cd7e72a2b89a98.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 83, + 192, + 96, + 199 + ], + "lines": [ + { + "bbox": [ + 83, + 192, + 96, + 199 + ], + "spans": [ + { + "bbox": [ + 83, + 192, + 96, + 199 + ], + "type": "text", + "content": "k=1" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 132, + 134, + 214, + 192 + ], + "blocks": [ + { + "bbox": [ + 132, + 134, + 214, + 192 + ], + "lines": [ + { + "bbox": [ + 132, + 134, + 214, + 192 + ], + "spans": [ + { + "bbox": [ + 132, + 134, + 214, + 192 + ], + "type": "image", + "image_path": "2444333a3d0e9c4b53c1d9ad7736497c9ddcaf41b4b42c32d2c0bbd8398d68ed.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 167, + 192, + 179, + 199 + ], + "lines": [ + { + "bbox": [ + 167, + 192, + 179, + 199 + ], + "spans": [ + { + "bbox": [ + 167, + 192, + 179, + 199 + ], + "type": "text", + "content": "k=2" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 215, + 134, + 298, + 192 + ], + "blocks": [ + { + "bbox": [ + 215, + 134, + 298, + 192 + ], + "lines": [ + { + "bbox": [ + 215, + 134, + 298, + 192 + ], + "spans": [ + { + "bbox": [ + 215, + 134, + 298, + 192 + ], + "type": "image", + "image_path": "1ff923ab289a6f553b4149f73dd92552d11ca6d8600f37d309c55b6a1e606b26.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 249, + 192, + 262, + 199 + ], + "lines": [ + { + "bbox": [ + 249, + 192, + 262, + 199 + ], + "spans": [ + { + "bbox": [ + 249, + 192, + 262, + 199 + ], + "type": "text", + "content": "k=3" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 282, + 287, + 342 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 282, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 46, + 282, + 287, + 342 + ], + "type": "text", + "content": "higher precision and recall because of its ability to output multiple high quality regions per image. While LOST and TokenCut output high quality boxes, they cannot output more than one box per image. SS on the other hand, outputs multiple boxes but with poor quality." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 342, + 287, + 450 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 342, + 287, + 450 + ], + "spans": [ + { + "bbox": [ + 46, + 342, + 287, + 450 + ], + "type": "text", + "content": "Multiple Object Localization: We compare with LOD, the state-of-the-art method on the multi-object localization benchmark proposed by LOST using the code released by authors. On VOC2007, we attain an odAP[0.5:0.95] of 6.43 compared to 5.35 attained by LOD, an improvement of 1.09 percentage points. On the COCO20k dataset, we attain a performance of 1.70 (compared to 1.53 achieved by LOD) on the harder odAP[0.50:0.95] metric. Note, we do not compare with rOSD [49] as LOD [50] outperforms it." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 46, + 450, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 450, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 450, + 287, + 714 + ], + "type": "text", + "content": "Single Object Localization: Table 4 compares the results of our method on single object localization with recent methods on PASCAL VOC 2007, 2012 and COCO20k respectively. We use the CorLoc metric to evaluate methods. Note that MOST is a multiple object localization method and this setup evaluates the ability of methods to output a single region. Since MOST outputs multiple boxes, we use the heuristic, average best overlap (for evaluating object proposals in [46]), to select one region per image. The numbers reported for MOST in this table are the \"best\" case scenario. We outperform LOST by 12.9, 13.4 and 16.4 percentage points on VOC 2007, 2012 and COCO20k respectively. We outperform TokenCut [53] by 6, 5.3 and 8.3 percentage points on the three datasets respectively. To obtain multiple regions per image, authors of LOST train a foreground object detector using the regions obtained by their method as supervision, called LOST+CAD [41]. This method can output multiple boxes per image and from Table 4, even without any training, our method outperforms LOST+CAD and TokenCut+CAD by 9.1, 7, 9.6 and 3.4, 2.1, 4.5 percentage points on VOC 2007, 2012 and COCO20k respectively." + } + ] + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 306, + 70, + 429, + 137 + ], + "blocks": [ + { + "bbox": [ + 306, + 70, + 429, + 137 + ], + "lines": [ + { + "bbox": [ + 306, + 70, + 429, + 137 + ], + "spans": [ + { + "bbox": [ + 306, + 70, + 429, + 137 + ], + "type": "image", + "image_path": "010347b59054872fef604556ece16985ab91d6365d4ca175344e727748b5dd51.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 432, + 70, + 555, + 137 + ], + "blocks": [ + { + "bbox": [ + 432, + 70, + 555, + 137 + ], + "lines": [ + { + "bbox": [ + 432, + 70, + 555, + 137 + ], + "spans": [ + { + "bbox": [ + 432, + 70, + 555, + 137 + ], + "type": "image", + "image_path": "4f7ae4bfa2cbc7382b89e488d51cd4abedb920a2cbf08157c833d2ddb57cd7e8.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 306, + 138, + 429, + 205 + ], + "blocks": [ + { + "bbox": [ + 46, + 213, + 299, + 262 + ], + "lines": [ + { + "bbox": [ + 46, + 213, + 299, + 262 + ], + "spans": [ + { + "bbox": [ + 46, + 213, + 299, + 262 + ], + "type": "text", + "content": "Figure 4: Effect of kernel size: Different kernel sizes can identify different tokens as belonging to the foreground. Multiple kernels help eliminate noisy predictions (first triplet) and missed predictions (second triplet)." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 306, + 138, + 429, + 205 + ], + "lines": [ + { + "bbox": [ + 306, + 138, + 429, + 205 + ], + "spans": [ + { + "bbox": [ + 306, + 138, + 429, + 205 + ], + "type": "image", + "image_path": "525d2ac72d6b24c4c0623acf84b0c63b906b8b377cbec83fc10c3e431982134e.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 213, + 556, + 262 + ], + "lines": [ + { + "bbox": [ + 304, + 213, + 556, + 262 + ], + "spans": [ + { + "bbox": [ + 304, + 213, + 556, + 262 + ], + "type": "text", + "content": "Figure 5: Figure demonstrating the effect of clustering in MOST: Each image consists of a bounding box generated from a pool. We observe that each pool focuses on different foreground instance." + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_caption" + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 432, + 138, + 555, + 205 + ], + "blocks": [ + { + "bbox": [ + 432, + 138, + 555, + 205 + ], + "lines": [ + { + "bbox": [ + 432, + 138, + 555, + 205 + ], + "spans": [ + { + "bbox": [ + 432, + 138, + 555, + 205 + ], + "type": "image", + "image_path": "480e4d325d6557577d4d05c05a5fc987019fb8b3a6f6305cd1b54517085c7ac4.jpg" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_body" + } + ], + "index": 19 + }, + { + "type": "image", + "bbox": [ + 307, + 280, + 367, + 324 + ], + "blocks": [ + { + "bbox": [ + 307, + 280, + 367, + 324 + ], + "lines": [ + { + "bbox": [ + 307, + 280, + 367, + 324 + ], + "spans": [ + { + "bbox": [ + 307, + 280, + 367, + 324 + ], + "type": "image", + "image_path": "f4fda4b897aeb4e8590f31d2437da3f249e09a39aecee38cfb45a2e124e1f5fe.jpg" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 333, + 545, + 358 + ], + "lines": [ + { + "bbox": [ + 305, + 333, + 545, + 358 + ], + "spans": [ + { + "bbox": [ + 305, + 333, + 545, + 358 + ], + "type": "text", + "content": "Figure 6: Figure demonstrating the effect of clustering in MOST. Eliminating the clustering results in noisier outputs." + } + ] + } + ], + "index": 25, + "angle": 0, + "type": "image_caption" + } + ], + "index": 21 + }, + { + "type": "image", + "bbox": [ + 367, + 280, + 425, + 324 + ], + "blocks": [ + { + "bbox": [ + 367, + 280, + 425, + 324 + ], + "lines": [ + { + "bbox": [ + 367, + 280, + 425, + 324 + ], + "spans": [ + { + "bbox": [ + 367, + 280, + 425, + 324 + ], + "type": "image", + "image_path": "26ff3ae1e3c2dc6a1b0328cb2381d62833af696b2f4a15af57e17d84e1b132f7.jpg" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_body" + } + ], + "index": 22 + }, + { + "type": "image", + "bbox": [ + 427, + 280, + 485, + 324 + ], + "blocks": [ + { + "bbox": [ + 427, + 280, + 485, + 324 + ], + "lines": [ + { + "bbox": [ + 427, + 280, + 485, + 324 + ], + "spans": [ + { + "bbox": [ + 427, + 280, + 485, + 324 + ], + "type": "image", + "image_path": "03da880ef6407f4afd06eef657b13ebcc2340098742602d56df19d668b0975dd.jpg" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_body" + } + ], + "index": 23 + }, + { + "type": "image", + "bbox": [ + 486, + 280, + 545, + 324 + ], + "blocks": [ + { + "bbox": [ + 486, + 280, + 545, + 324 + ], + "lines": [ + { + "bbox": [ + 486, + 280, + 545, + 324 + ], + "spans": [ + { + "bbox": [ + 486, + 280, + 545, + 324 + ], + "type": "image", + "image_path": "409d4e0ba1560f9f508de4c72407b3ee65add926faf33788dc51474bba082699.jpg" + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_body" + } + ], + "index": 24 + }, + { + "bbox": [ + 304, + 387, + 545, + 554 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 387, + 545, + 554 + ], + "spans": [ + { + "bbox": [ + 304, + 387, + 545, + 554 + ], + "type": "text", + "content": "Discovery Setup: This setup evaluates the true object discovery performance as the localized boxes are used to discover semantic groups. Following LOST [41], we first cluster the features of the localized objects using K-means clustering. For VOC 2007 and " + }, + { + "bbox": [ + 304, + 387, + 545, + 554 + ], + "type": "inline_equation", + "content": "2007 + 2012" + }, + { + "bbox": [ + 304, + 387, + 545, + 554 + ], + "type": "text", + "content": " trainval splits, we use 20, 30 and 40 clusters. We use 80, 90 and 100 clusters for COCO20k train split. We report the results of experiments on VOC 2007, " + }, + { + "bbox": [ + 304, + 387, + 545, + 554 + ], + "type": "inline_equation", + "content": "07 + 12" + }, + { + "bbox": [ + 304, + 387, + 545, + 554 + ], + "type": "text", + "content": " trainval sets on VOC 2007 test set. For experiments on COCO20k, we report results on the COCO validation set. Results are tabulated in Table 3. MOST outperforms LOST in most settings with the margin of improvement higher for more number of clusters and more cluttered datasets like COCO. For more details on clustering and training refer to supplementary." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 304, + 558, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 546, + 713 + ], + "type": "text", + "content": "Finally, we evaluate the performance of MOST on large-scale object discovery setup introduced in [34]. For this setup, we use the area under the purity coverage plot as the metric. [34] automatically identifies the number of clusters and obtains an AuC@0.5 of " + }, + { + "bbox": [ + 304, + 558, + 546, + 713 + ], + "type": "inline_equation", + "content": "3.6\\%" + }, + { + "bbox": [ + 304, + 558, + 546, + 713 + ], + "type": "text", + "content": " on the COCO 2014 train set. We extract the DINO [CLS] token features of regions obtained from MOST for K-Means clustering. To avoid specifying the number of clusters manually, we employ the \"kneedle\" method [38] to get the optimal number of clusters (more details in supplementary). Next, we randomly sample 10000 features from the whole dataset and cluster them using K-means with the optimal number of clusters. This subsampling avoids loading all the features into mem" + } + ] + } + ], + "index": 27 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15829" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 72, + 284, + 177 + ], + "blocks": [ + { + "bbox": [ + 51, + 72, + 284, + 177 + ], + "lines": [ + { + "bbox": [ + 51, + 72, + 284, + 177 + ], + "spans": [ + { + "bbox": [ + 51, + 72, + 284, + 177 + ], + "type": "image", + "image_path": "af60b2091b25194435a10fdb72d50c7ae4dd7351552d05fff911fbaf9add310c.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 187, + 288, + 248 + ], + "lines": [ + { + "bbox": [ + 46, + 187, + 288, + 248 + ], + "spans": [ + { + "bbox": [ + 46, + 187, + 288, + 248 + ], + "type": "text", + "content": "Figure 7: Recall analysis: Comparison of recall values of MOST, MOST+CAD with LOST and LOST+CAD. LOST generates one bounding box per image. MOST+CAD, MOST have higher recall and cover more ground-truth objects for a fixed set of boxes." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 269, + 287, + 353 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 269, + 287, + 353 + ], + "spans": [ + { + "bbox": [ + 46, + 269, + 287, + 353 + ], + "type": "text", + "content": "ory. MOST + optimal K-means achieves an AuC@0.5 of " + }, + { + "bbox": [ + 46, + 269, + 287, + 353 + ], + "type": "inline_equation", + "content": "8.74\\%" + }, + { + "bbox": [ + 46, + 269, + 287, + 353 + ], + "type": "text", + "content": " on COCO 2014 train set. We use the cluster labels to train an object detector on the COCO train set and achieve an " + }, + { + "bbox": [ + 46, + 269, + 287, + 353 + ], + "type": "inline_equation", + "content": "\\mathrm{AP / AP}_{50}" + }, + { + "bbox": [ + 46, + 269, + 287, + 353 + ], + "type": "text", + "content": " of " + }, + { + "bbox": [ + 46, + 269, + 287, + 353 + ], + "type": "inline_equation", + "content": "3.9 / 9.5\\%" + }, + { + "bbox": [ + 46, + 269, + 287, + 353 + ], + "type": "text", + "content": " compared to " + }, + { + "bbox": [ + 46, + 269, + 287, + 353 + ], + "type": "inline_equation", + "content": "5.2\\%" + }, + { + "bbox": [ + 46, + 269, + 287, + 353 + ], + "type": "inline_equation", + "content": "\\mathrm{AP}_{50}" + }, + { + "bbox": [ + 46, + 269, + 287, + 353 + ], + "type": "text", + "content": " obtained by [34] on COCO validation set. For more experiments on unsupervised saliency detection and weakly supervised localization, refer to the supplementary." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 360, + 173, + 372 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 360, + 173, + 372 + ], + "spans": [ + { + "bbox": [ + 47, + 360, + 173, + 372 + ], + "type": "text", + "content": "4.4. Ablation Experiments" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 378, + 287, + 545 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 378, + 287, + 545 + ], + "spans": [ + { + "bbox": [ + 46, + 378, + 287, + 545 + ], + "type": "text", + "content": "Effect of kernel size: The EBA module performs box analysis in a sliding window fashion using boxes (or kernels) of different sizes. We implement this efficiently using a pooling operation. We visualize the effect of the size of pooling kernels on the final output in Fig. 4. We observe that the majority voting performed in EBA, helps in removing noisy predictions in the first triplet, where a box identified by kernel of size 1 is eliminated by majority voting of kernels with larger receptive field. In the second triplet in Fig. 4, an object which was missed by the lower order kernels " + }, + { + "bbox": [ + 46, + 378, + 287, + 545 + ], + "type": "inline_equation", + "content": "(\\mathrm{k} = [1,4])" + }, + { + "bbox": [ + 46, + 378, + 287, + 545 + ], + "type": "text", + "content": ", can be picked up with a higher order kernel " + }, + { + "bbox": [ + 46, + 378, + 287, + 545 + ], + "type": "inline_equation", + "content": "(\\mathrm{k} = 5)" + }, + { + "bbox": [ + 46, + 378, + 287, + 545 + ], + "type": "text", + "content": ". For all our experiments, we use kernels of sizes upto 5 (i.e. " + }, + { + "bbox": [ + 46, + 378, + 287, + 545 + ], + "type": "inline_equation", + "content": "\\mathrm{k} = [1,5]" + }, + { + "bbox": [ + 46, + 378, + 287, + 545 + ], + "type": "text", + "content": "). For quantitative results on the effect of kernel sizes, refer to the supplementary." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 545, + 287, + 617 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 545, + 287, + 617 + ], + "spans": [ + { + "bbox": [ + 46, + 545, + 287, + 617 + ], + "type": "text", + "content": "Effect of clustering: MOST performs clustering with the token locations as features to obtain pools. Each pool contains tokens belonging to a foreground object. We show the effect of clustering qualitatively in Fig. 5. We observe that each pool focuses on one foreground object and illustrate the bounding boxes extracted from each pool." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 617, + 287, + 701 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 287, + 701 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 287, + 701 + ], + "type": "text", + "content": "Each pool contains tokens belonging to a foreground object. We show the effect of forming pools qualitatively in Fig. 6. The first image in each pair shows the output of MOST without clustering to form pools and the second image shows the output with the formation. We observe that, without clustering, each token can generate a bounding box resulting in noisier outputs." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 701, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 701, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 47, + 701, + 287, + 714 + ], + "type": "text", + "content": "Recall of boxes: To analyze the object localization perfor" + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 345, + 91, + 507, + 162 + ], + "blocks": [ + { + "bbox": [ + 310, + 71, + 539, + 83 + ], + "lines": [ + { + "bbox": [ + 310, + 71, + 539, + 83 + ], + "spans": [ + { + "bbox": [ + 310, + 71, + 539, + 83 + ], + "type": "text", + "content": "Table 5: Effect of backbone on single-object localization" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 345, + 91, + 507, + 162 + ], + "lines": [ + { + "bbox": [ + 345, + 91, + 507, + 162 + ], + "spans": [ + { + "bbox": [ + 345, + 91, + 507, + 162 + ], + "type": "table", + "html": "
BackboneVOC 2007VOC 2012COCO20k
ViT-S/884.2586.0080.50
ViT-S/1674.8077.4068.60
ViT-B/885.4087.0081.73
ViT-B/1672.7276.2867.20
", + "image_path": "24934d015d4dfe64678d1bae29d424bdbe1afcc4531cf6e1400344ac5458304b.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 183, + 545, + 386 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 183, + 545, + 386 + ], + "spans": [ + { + "bbox": [ + 304, + 183, + 545, + 386 + ], + "type": "text", + "content": "mance of MOST, we compare its recall with LOST and TokenCut on VOC 07, 12 and COCO20k datasets in Fig. 7. The x-axis represents the maximum number of boxes allowed per image and the y axis plots the recall. LOST and TokenCut generate only one box per image and hence have fixed recall in all the plots. MOST can generate more boxes and hence have higher recall than LOST and TokenCut. [41] trains a class agnostic detector (CAD) to output multiple boxes per image using the output of LOST as supervision. Without a single step of training, MOST performs competitively against LOST+CAD on all the datasets. With a class agnostic detector, MOST+CAD outperforms LOST, TokenCut and their CAD counterparts comfortably on all the datasets. On COCO20k, a much harder dataset, MOST+CAD outperforms all the methods with a significant margin demonstrating its superior localization abilities." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 388, + 545, + 508 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 388, + 545, + 508 + ], + "spans": [ + { + "bbox": [ + 304, + 388, + 545, + 508 + ], + "type": "text", + "content": "Effect of EBA: We study the effect of EBA on single-object localization. The task of the EBA module is to identify tokens on foreground instances from similarity maps. We replace the EBA module with the strategy used by LOST [41], effectively giving LOST the ability to localize multiple objects. We use top-100 patches and this system achieves a CorLoc of 63.66 (compared to 74.84 of MOST). The EBA module can automatically pick the right tokens, unlike LOST to localize multiple objects. This experiment demonstrates the benefit of the proposed EBA module." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 509, + 545, + 663 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 509, + 545, + 663 + ], + "spans": [ + { + "bbox": [ + 304, + 509, + 545, + 663 + ], + "type": "text", + "content": "Timing analysis: MOST can localize multiple objects per image and does so by analyzing the similarity maps of all the tokens which is computationally more expensive. To understand this requirement, we perform a timing analysis. On average, LOST takes 0.008s per image while MOST takes 0.3s. MOST obtains a recall of 0.19, 0.21, and 0.08 on VOC07, VOC12, and COCO20k respectively (compared to 0.13, 0.15, and 0.03 of LOST). This translates to localizing an additional 750, 2400, and 7200 instances than LOST on VOC07, VOC12, and COCO20k respectively. We believe the additional time taken by MOST is justified by the improvement in recall performance which is essential for an object localization method." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "Effect of backbone: We study the effect of backbone on MOST in Table 5. We observe that backbones with a smaller patch size can localize more objects, especially smaller ones (refer to supplementary for qualitative results)" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15830" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 52, + 70, + 132, + 125 + ], + "blocks": [ + { + "bbox": [ + 52, + 70, + 132, + 125 + ], + "lines": [ + { + "bbox": [ + 52, + 70, + 132, + 125 + ], + "spans": [ + { + "bbox": [ + 52, + 70, + 132, + 125 + ], + "type": "image", + "image_path": "0aff19d213a50846bc9baab00f055f202ab4631c7d08ca181a3506ac8ee550d5.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 133, + 70, + 209, + 125 + ], + "blocks": [ + { + "bbox": [ + 133, + 70, + 209, + 125 + ], + "lines": [ + { + "bbox": [ + 133, + 70, + 209, + 125 + ], + "spans": [ + { + "bbox": [ + 133, + 70, + 209, + 125 + ], + "type": "image", + "image_path": "1aa69e756f27a3c28756b6a3ce7627c833f3a4f16b977bcf587e18d6a49c1dcc.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 209, + 70, + 295, + 125 + ], + "blocks": [ + { + "bbox": [ + 209, + 70, + 295, + 125 + ], + "lines": [ + { + "bbox": [ + 209, + 70, + 295, + 125 + ], + "spans": [ + { + "bbox": [ + 209, + 70, + 295, + 125 + ], + "type": "image", + "image_path": "e93b608b8f73d927ad44349baa5df2eef466966e078b3a80bd631b77b906a0e4.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 296, + 70, + 336, + 125 + ], + "blocks": [ + { + "bbox": [ + 296, + 70, + 336, + 125 + ], + "lines": [ + { + "bbox": [ + 296, + 70, + 336, + 125 + ], + "spans": [ + { + "bbox": [ + 296, + 70, + 336, + 125 + ], + "type": "image", + "image_path": "fef149cf998a49f473e54abd7407ee942bf6475d9598c03a7716cad7fbfdae42.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 337, + 70, + 415, + 125 + ], + "blocks": [ + { + "bbox": [ + 337, + 70, + 415, + 125 + ], + "lines": [ + { + "bbox": [ + 337, + 70, + 415, + 125 + ], + "spans": [ + { + "bbox": [ + 337, + 70, + 415, + 125 + ], + "type": "image", + "image_path": "261952cba14f3e6bc96bd1ff5969acd501d588a312643ee40d19633c27a5bba5.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 416, + 70, + 460, + 125 + ], + "blocks": [ + { + "bbox": [ + 416, + 70, + 460, + 125 + ], + "lines": [ + { + "bbox": [ + 416, + 70, + 460, + 125 + ], + "spans": [ + { + "bbox": [ + 416, + 70, + 460, + 125 + ], + "type": "image", + "image_path": "a900dbf02e419bf63da109f5f49292f67c8f1d84130624bd2a63d667b9001060.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 460, + 70, + 541, + 125 + ], + "blocks": [ + { + "bbox": [ + 460, + 70, + 541, + 125 + ], + "lines": [ + { + "bbox": [ + 460, + 70, + 541, + 125 + ], + "spans": [ + { + "bbox": [ + 460, + 70, + 541, + 125 + ], + "type": "image", + "image_path": "a8e2c006c95c3b07b22dc9959dff16dc33a6c8eb9fb5cc9e504ad29c41beec49.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 52, + 127, + 133, + 182 + ], + "blocks": [ + { + "bbox": [ + 52, + 127, + 133, + 182 + ], + "lines": [ + { + "bbox": [ + 52, + 127, + 133, + 182 + ], + "spans": [ + { + "bbox": [ + 52, + 127, + 133, + 182 + ], + "type": "image", + "image_path": "235f62354645ddafbf698dc5ebae130d5d6733189102d6d48a7374453ddaf205.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 135, + 127, + 214, + 182 + ], + "blocks": [ + { + "bbox": [ + 135, + 127, + 214, + 182 + ], + "lines": [ + { + "bbox": [ + 135, + 127, + 214, + 182 + ], + "spans": [ + { + "bbox": [ + 135, + 127, + 214, + 182 + ], + "type": "image", + "image_path": "27af0758d2f87a029aff3ab79076317d5e0a9f218945d99326e376020f973dce.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 145, + 186, + 203, + 197 + ], + "lines": [ + { + "bbox": [ + 145, + 186, + 203, + 197 + ], + "spans": [ + { + "bbox": [ + 145, + 186, + 203, + 197 + ], + "type": "text", + "content": "(a) VOC 07+12" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 215, + 127, + 295, + 182 + ], + "blocks": [ + { + "bbox": [ + 215, + 127, + 295, + 182 + ], + "lines": [ + { + "bbox": [ + 215, + 127, + 295, + 182 + ], + "spans": [ + { + "bbox": [ + 215, + 127, + 295, + 182 + ], + "type": "image", + "image_path": "087da7178ef671c5d2e5f47c8f7fb7ed50313d4407cb5e939b3ffb9303c488ed.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 207, + 545, + 243 + ], + "lines": [ + { + "bbox": [ + 46, + 207, + 545, + 243 + ], + "spans": [ + { + "bbox": [ + 46, + 207, + 545, + 243 + ], + "type": "text", + "content": "Figure 8: Qualitative results of MOST on VOC 07, 12 and COCO: MOST can localize multiple objects in cluttered scenes without training. Localization ability of MOST is not limited by the biases of annotators and can localize rocks, mountains, branches, water bodies, etc." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 296, + 127, + 377, + 182 + ], + "blocks": [ + { + "bbox": [ + 296, + 127, + 377, + 182 + ], + "lines": [ + { + "bbox": [ + 296, + 127, + 377, + 182 + ], + "spans": [ + { + "bbox": [ + 296, + 127, + 377, + 182 + ], + "type": "image", + "image_path": "8e57c3b2f8693e9c9af96d34a03291c0db18f338f42ed2a256f057b8bbd16b47.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 378, + 127, + 459, + 182 + ], + "blocks": [ + { + "bbox": [ + 378, + 127, + 459, + 182 + ], + "lines": [ + { + "bbox": [ + 378, + 127, + 459, + 182 + ], + "spans": [ + { + "bbox": [ + 378, + 127, + 459, + 182 + ], + "type": "image", + "image_path": "59139d447aa3fddc3d05bb8092541a23300a49e41a88f74b1737249351c3664d.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 400, + 186, + 439, + 197 + ], + "lines": [ + { + "bbox": [ + 400, + 186, + 439, + 197 + ], + "spans": [ + { + "bbox": [ + 400, + 186, + 439, + 197 + ], + "type": "text", + "content": "(b) COCO" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 460, + 127, + 541, + 182 + ], + "blocks": [ + { + "bbox": [ + 460, + 127, + 541, + 182 + ], + "lines": [ + { + "bbox": [ + 460, + 127, + 541, + 182 + ], + "spans": [ + { + "bbox": [ + 460, + 127, + 541, + 182 + ], + "type": "image", + "image_path": "0f8107af5ca39d2fee6a948fc7de1a365c7a8ba61acf60733d4d0267af3fbcbd.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "table", + "bbox": [ + 48, + 330, + 287, + 435 + ], + "blocks": [ + { + "bbox": [ + 46, + 248, + 288, + 320 + ], + "lines": [ + { + "bbox": [ + 46, + 248, + 288, + 320 + ], + "spans": [ + { + "bbox": [ + 46, + 248, + 288, + 320 + ], + "type": "text", + "content": "Table 6: Results on unsupervised saliency detection: We compare MOST to state-of-the-art unsupervised saliency detections methods. Top results are in bold and second best is highlighted in blue. Ability to detect multiple objects in images is a good tradeoff for a slight drop in performance on saliency detection" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 330, + 287, + 435 + ], + "lines": [ + { + "bbox": [ + 48, + 330, + 287, + 435 + ], + "spans": [ + { + "bbox": [ + 48, + 330, + 287, + 435 + ], + "type": "table", + "html": "
MethodECSSDDUTSDUT-OMRON
max Fβ IoU Acc (%)max Fβ IoU Acc (%)max Fβ IoU Acc (%)
DeepUSPS[32]58.444.079.542.530.577.341.430.577.9
BigBiGAN [51]78.267.289.960.849.887.854.945.385.6
E-BigBiGAN [51]79.768.490.662.451.188.256.346.486.0
LOST [41]75.762.588.061.852.087.147.440.279.6
TCut [53]80.371.291.867.257.690.360.053.388.0
MOST79.163.189.066.653.889.757.047.587.0
", + "image_path": "2f9e794ab029f0990907d7f5242cdb8d8c799bf1b35dbe92b2efcebbd72ff55e.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "table_body" + } + ], + "index": 17 + }, + { + "bbox": [ + 46, + 442, + 287, + 491 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 442, + 287, + 491 + ], + "spans": [ + { + "bbox": [ + 46, + 442, + 287, + 491 + ], + "type": "text", + "content": "resulting in a higher CorLoc. This comes at a cost of producing noisier outputs. We refer interested readers to the supplementary for more analysis and qualitative results on the effect of backbones and patch sizes." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 47, + 502, + 182, + 514 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 502, + 182, + 514 + ], + "spans": [ + { + "bbox": [ + 47, + 502, + 182, + 514 + ], + "type": "text", + "content": "4.5. Additional Experiments" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": "Unsupervised Saliency Detection: MOST can easily be extended to unsupervised saliency detection. We experiment with ECSSD [40], DUTS [26] and DUT-OMRON [5] datasets and use the metrics used by [41, 53] for evaluation. All these datasets require methods to segment the salient object in an image. Hence, naively using MOST doesn't perform well. To extend MOST for saliency detection, we select the largest pool and use the similarity map computed using its tokens as the saliency map. In Table 6, we compare MOST with TokenCut and LOST on the three datasets. MOST outperforms LOST comfortably on all the metrics, datasets and fares competitively against TokenCut. We believe that the ability to detect multiple objects in images is a good tradeoff for a slight drop in performance on saliency detection. We refer interested readers to the supplementary for qualitative results on saliency detection." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 249, + 545, + 310 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 249, + 545, + 310 + ], + "spans": [ + { + "bbox": [ + 304, + 249, + 545, + 310 + ], + "type": "text", + "content": "Weakly supervised localization: We evaluate MOST on weakly supervised object localization on CUB-200 [55] and Imagenet [37] datasets respectively, and achieve a CorLoc of 92.42 (vs. 91.8 of TokenCut) on CUB-200 and a CorLoc of 71.4 (vs. 65.4 of TokenCut)." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 306, + 316, + 421, + 329 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 316, + 421, + 329 + ], + "spans": [ + { + "bbox": [ + 306, + 316, + 421, + 329 + ], + "type": "text", + "content": "4.6. Qualitative Results:" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 334, + 545, + 454 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 334, + 545, + 454 + ], + "spans": [ + { + "bbox": [ + 304, + 334, + 545, + 454 + ], + "type": "text", + "content": "We illustrate qualitative results of MOST on VOC2007, 2012 and COCO datasets in Fig. 8. Fig. 8a shows results on VOC 2007 and 2012 and Fig. 8b shows results on COCO dataset. MOST is capable of localizing fairly complex scenes in all the three datasets. We observe that, such unsupervised localization methods are not limited by the categories annotated by humans but can localize regions of \"stuff\" like sign boards (third image in the first row of Fig. 8a right), rocks (last image of last row in Fig. 8b), and water bodies (first image in second row of Fig. 8b)." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 306, + 464, + 378, + 475 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 464, + 378, + 475 + ], + "spans": [ + { + "bbox": [ + 306, + 464, + 378, + 475 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 304, + 483, + 545, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 483, + 545, + 651 + ], + "spans": [ + { + "bbox": [ + 304, + 483, + 545, + 651 + ], + "type": "text", + "content": "We present MOST, an effective method for localizing multiple objects in complex images without a single annotation. MOST leverages object segmentation properties of transformers trained using DINO [3]. We show that the ability of MOST to localize multiple objects in an image is very effective on several object localization and discovery benchmarks. In particular, MOST outperforms recent state-of-the-art methods that train a class agnostic detector, on the task of single object localization, without any training. Further, we show that MOST achieves higher recall and covers more ground truth objects for a fixed set of boxes than LOST [41], a contemporary work on object localization. Finally, we extend MOST to the task of unsupervised saliency detection and report competitive results with recent works." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "Acknowledgement. This project was partially supported by DARPA SemaFor (HR001119S0085) and DARPA SAIL-ON (W911NF2020009), and Amazon Research Award to Abhinav Shrivastava. Rama Chellappa was supported by an ONR MURI (N00014-20-1-2787)." + } + ] + } + ], + "index": 26 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15831" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 91, + 288, + 707 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 134 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 134 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 134 + ], + "type": "text", + "content": "[1] Ankan Bansal, Sai Saketh Rambhatla, Abhinav Shrivastava, and Rama Chellappa. Detecting human-object interactions via functional generalization. Thirty-Fourth AAAI Conference on Artificial Intelligence, 2020. 1" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 134, + 287, + 177 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 134, + 287, + 177 + ], + "spans": [ + { + "bbox": [ + 53, + 134, + 287, + 177 + ], + "type": "text", + "content": "[2] Amir Bar, Xin Wang, Vadim Kantorov, Colorado J Reed, Roei Herzig, Gal Chechik, Anna Rohrbach, Trevor Darrell, and Amir Globerson. Detreg: Unsupervised pretraining with region priors for object detection, 2021. 5, 6" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 177, + 288, + 231 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 177, + 288, + 231 + ], + "spans": [ + { + "bbox": [ + 53, + 177, + 288, + 231 + ], + "type": "text", + "content": "[3] Mathilde Caron, Hugo Touvron, Ishan Misra, Hervé Jégou, Julien Mairal, Piotr Bojanowski, and Armand Joulin. Emerging properties in self-supervised vision transformers. In Proceedings of the International Conference on Computer Vision (ICCV), 2021. 1, 2, 3, 5, 6, 9" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 231, + 288, + 295 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 231, + 288, + 295 + ], + "spans": [ + { + "bbox": [ + 53, + 231, + 288, + 295 + ], + "type": "text", + "content": "[4] Minsu Cho, Suha Kwak, Cordelia Schmid, and Jean Ponce. Unsupervised Object Discovery and Localization in the Wild: Part-based Matching with Bottom-up Region Proposals. In CVPR - IEEE Conference on Computer Vision & Pattern Recognition, pages 1201-1210, Boston, United States, June 2015. IEEE. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 296, + 288, + 350 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 296, + 288, + 350 + ], + "spans": [ + { + "bbox": [ + 53, + 296, + 288, + 350 + ], + "type": "text", + "content": "[5] Yang Chuan, Zhang Lihe, Lu Huchuan Ruan Xiang, and Yang Ming-Hsuan. Saliency detection via graph-based manifold ranking. In Computer Vision and Pattern Recognition (CVPR), 2013 IEEE Conference on, pages 3166-3173. IEEE, 2013. 9" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 350, + 288, + 436 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 350, + 288, + 436 + ], + "spans": [ + { + "bbox": [ + 53, + 350, + 288, + 436 + ], + "type": "text", + "content": "[6] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. BERT: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers), pages 4171–4186, Minneapolis, Minnesota, June 2019. Association for Computational Linguistics. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 436, + 288, + 490 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 436, + 288, + 490 + ], + "spans": [ + { + "bbox": [ + 53, + 436, + 288, + 490 + ], + "type": "text", + "content": "[7] Akshay Dhamija, Manuel Gunther, Jonathan Ventura, and Terrance Boult. The overlooked elephant of object detection: Open set. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision (WACV), March 2020. 1" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 490, + 288, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 490, + 288, + 533 + ], + "spans": [ + { + "bbox": [ + 53, + 490, + 288, + 533 + ], + "type": "text", + "content": "[8] Carl Doersch, Abhinav Gupta, and Alexei A. Efros. Context as supervisory signal: Discovering objects with predictable context. In European Conference on Computer Vision (ECCV), pages 362-377. Springer, 2014. 2, 5" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 533, + 288, + 597 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 533, + 288, + 597 + ], + "spans": [ + { + "bbox": [ + 53, + 533, + 288, + 597 + ], + "type": "text", + "content": "[9] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. ICLR, 2021. 3, 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 597, + 288, + 662 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 597, + 288, + 662 + ], + "spans": [ + { + "bbox": [ + 47, + 597, + 288, + 662 + ], + "type": "text", + "content": "[10] Debidatta Dwibedi, Yusuf Aytar, Jonathan Tompson, Pierre Sermanet, and Andrew Zisserman. With a little help from my friends: Nearest-neighbor contrastive learning of visual representations. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 9588–9597, October 2021. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 662, + 288, + 707 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 662, + 288, + 707 + ], + "spans": [ + { + "bbox": [ + 47, + 662, + 288, + 707 + ], + "type": "text", + "content": "[11] Martin Ester, Hans-Peter Kriegel, Jörg Sander, and Xiaowei Xu. A density-based algorithm for discovering clusters in large spatial databases with noise. In Proceedings of the Second International Conference on Knowledge Discovery and" + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 707 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 83 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 83 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 83 + ], + "type": "text", + "content": "Data Mining, KDD'96, page 226-231. AAAI Press, 1996. 4" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 308, + 83, + 545, + 126 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 83, + 545, + 126 + ], + "spans": [ + { + "bbox": [ + 308, + 83, + 545, + 126 + ], + "type": "text", + "content": "[12] Mark Everingham, Luc Van Gool, Christopher K. I. Williams, John Winn, and Andrew Zisserman. The pascal visual object classes (voc) challenge. International Journal of Computer Vision, 88(2):303-338, 2010. 2, 5" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 308, + 126, + 545, + 169 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 126, + 545, + 169 + ], + "spans": [ + { + "bbox": [ + 308, + 126, + 545, + 169 + ], + "type": "text", + "content": "[13] Georgia Gkioxari, Ross B. Girshick, Piotr Dólar, and Kaiming He. Detecting and recognizing human-object interactions. 2018 IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8359-8367, 2018. 1" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 169, + 545, + 212 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 169, + 545, + 212 + ], + "spans": [ + { + "bbox": [ + 308, + 169, + 545, + 212 + ], + "type": "text", + "content": "[14] Agrim Gupta, Piotr Dollar, and Ross Girshick. LVIS: A dataset for large vocabulary instance segmentation. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2019. 1" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 212, + 545, + 266 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 212, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 308, + 212, + 545, + 266 + ], + "type": "text", + "content": "[15] Kai Han, Sylvestre-Alvise Rebuffi, Sebastien Ehrhardt, Andrea Vedaldi, and Andrew Zisserman. Automatically discovering and learning new visual categories with ranking statistics. In Proceedings of the International Conference on Learning Representations (ICLR), 2020. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 266, + 545, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 266, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 308, + 266, + 545, + 308 + ], + "type": "text", + "content": "[16] Kai Han, Andrea Vedaldi, and Andrew Zisserman. Learning to discover novel visual categories via deep transfer clustering. In Proceedings of the International Conference on Computer Vision (ICCV), 2019. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 309, + 545, + 352 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 309, + 545, + 352 + ], + "spans": [ + { + "bbox": [ + 308, + 309, + 545, + 352 + ], + "type": "text", + "content": "[17] Kaiming He, X. Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 770-778, 2016. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 352, + 545, + 384 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 352, + 545, + 384 + ], + "spans": [ + { + "bbox": [ + 308, + 352, + 545, + 384 + ], + "type": "text", + "content": "[18] Yen-Chang Hsu, Zhaoyang Lv, and Zsolt Kira. Deep image category discovery using a transferred similarity function. CoRR, abs/1612.01253, 2016. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 383, + 545, + 437 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 383, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 308, + 383, + 545, + 437 + ], + "type": "text", + "content": "[19] Yen-Chang Hsu, Zhaoyang Lv, and Zsolt Kira. Learning to cluster in order to transfer across domains and tasks. In 6th International Conference on Learning Representations, ICLR 2018, Vancouver, BC, Canada, April 30 - May 3, 2018, Conference Track Proceedings, 2018." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 437, + 545, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 437, + 545, + 491 + ], + "spans": [ + { + "bbox": [ + 308, + 437, + 545, + 491 + ], + "type": "text", + "content": "[20] Yen-Chang Hsu, Zhaoyang Lv, Joel Schlosser, Phillip Odom, and Zsolt Kira. Multi-class classification without multi-class labels. In 7th International Conference on Learning Representations, ICLR 2019, New Orleans, LA, USA, May 6-9, 2019, 2019. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 491, + 545, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 491, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 308, + 491, + 545, + 555 + ], + "type": "text", + "content": "[21] Ranjay Krishna, Yuke Zhu, Oliver Groth, Justin Johnson, Kenji Hata, Joshua Kravitz, Stephanie Chen, Yannis Kalantidis, Li-Jia Li, David A. Shamma, Michael S. Bernstein, and Li Fei-Fei. Visual genome: Connecting language and vision using crowdsourced dense image annotations. International Journal of Computer Vision, 123:32-73, 2016. 1" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 555, + 545, + 609 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 555, + 545, + 609 + ], + "spans": [ + { + "bbox": [ + 308, + 555, + 545, + 609 + ], + "type": "text", + "content": "[22] Suha Kwak, Minsu Cho, Ivan Laptev, Jean Ponce, and Cordelia Schmid. Unsupervised Object Discovery and Tracking in Video Collections. In ICCV - IEEE International Conference on Computer Vision, pages 3173-3181, Santiago, Chile, Dec. 2015. IEEE. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 609, + 545, + 653 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 609, + 545, + 653 + ], + "spans": [ + { + "bbox": [ + 308, + 609, + 545, + 653 + ], + "type": "text", + "content": "[23] Y. J. Lee and K. Grauman. Object-graphs for context-aware category discovery. In 2010 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 1-8, June 2010. 1, 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 653, + 545, + 684 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 653, + 545, + 684 + ], + "spans": [ + { + "bbox": [ + 308, + 653, + 545, + 684 + ], + "type": "text", + "content": "[24] Yong Jae Lee and Kristen Grauman. Learning the easy things first: Self-paced visual category discovery. In CVPR, pages 1721-1728. IEEE, 2011. 1, 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 684, + 545, + 707 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 684, + 545, + 707 + ], + "spans": [ + { + "bbox": [ + 308, + 684, + 545, + 707 + ], + "type": "text", + "content": "[25] Jian Li, Qian Du, and Caixin Sun. An improved box-counting method for image fractal dimension estimation." + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "15832" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 73, + 287, + 707 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 67, + 73, + 221, + 83 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 73, + 221, + 83 + ], + "spans": [ + { + "bbox": [ + 67, + 73, + 221, + 83 + ], + "type": "text", + "content": "Pattern Recognit., 42:2460-2469, 2009. 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 83, + 287, + 125 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 83, + 287, + 125 + ], + "spans": [ + { + "bbox": [ + 48, + 83, + 287, + 125 + ], + "type": "text", + "content": "[26] Wang Lijun, Lu Huchuan, Wang Yifan, Feng Mengyang, Wang Dong, Yin Baocai, and Ruan Xiang. Learning to detect salient objects with image-level supervision. In CVPR, 2017. 9" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 126, + 287, + 201 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 126, + 287, + 201 + ], + "spans": [ + { + "bbox": [ + 48, + 126, + 287, + 201 + ], + "type": "text", + "content": "[27] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólár, and C. Lawrence Zitnick. Microsoft coco: Common objects in context. In David Fleet, Tomas Pajdla, Bernt Schiele, and Tinne Tuytelaars, editors, Computer Vision – ECCV 2014, pages 740–755, Cham, 2014. Springer International Publishing. 1, 2, 5" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 202, + 287, + 235 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 202, + 287, + 235 + ], + "spans": [ + { + "bbox": [ + 48, + 202, + 287, + 235 + ], + "type": "text", + "content": "[28] Jing Z. Liu, Luduan Zhang, and Guang H. Yue. Fractal dimension in human cerebellum measured by magnetic resonance imaging. Biophysical journal, 85 6:4041-6, 2003. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 235, + 287, + 266 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 235, + 287, + 266 + ], + "spans": [ + { + "bbox": [ + 48, + 235, + 287, + 266 + ], + "type": "text", + "content": "[29] Cewu Lu, Ranjay Krishna, Michael Bernstein, and Li Fei-Fei. Visual relationship detection with language priors. In European Conference on Computer Vision, 2016. 1" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 266, + 286, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 266, + 286, + 308 + ], + "spans": [ + { + "bbox": [ + 48, + 266, + 286, + 308 + ], + "type": "text", + "content": "[30] Santiago Manen, Matthieu Guillaumin, and Luc Van Gool. Prime object proposals with randomized prim's algorithm. In 2013 IEEE International Conference on Computer Vision, pages 2536-2543, 2013. 1" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 309, + 287, + 363 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 309, + 287, + 363 + ], + "spans": [ + { + "bbox": [ + 48, + 309, + 287, + 363 + ], + "type": "text", + "content": "[31] Luke Melas-Kyriazi, Christian Rupprecht, Iro Laina, and Andrea Vedaldi. Deep spectral methods: A surprisingly strong baseline for unsupervised semantic segmentation and localization. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 363, + 287, + 416 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 363, + 287, + 416 + ], + "spans": [ + { + "bbox": [ + 48, + 363, + 287, + 416 + ], + "type": "text", + "content": "[32] Duc Tam Nguyen, Maximilian Dax, Chaithanya Kumar Mummadi, Thi-Phuong-Nhung Ngo, Thi Hoai Phuong Nguyen, Zhongyu Lou, and Thomas Brox. Deepusps: Deep robust unsupervised saliency prediction with self-supervision. In NeurIPS, 2019. 9" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 417, + 287, + 459 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 417, + 287, + 459 + ], + "spans": [ + { + "bbox": [ + 48, + 417, + 287, + 459 + ], + "type": "text", + "content": "[33] Roy E Plotnick, Robert H Gardner, William W Hargrove, Karen Prestegaard, and Martin Perlmutter. Lacunarity analysis: a general technique for the analysis of spatial patterns. Physical review E, 53(5):5461, 1996. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 459, + 287, + 513 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 459, + 287, + 513 + ], + "spans": [ + { + "bbox": [ + 48, + 459, + 287, + 513 + ], + "type": "text", + "content": "[34] Sai Saketh Rambhatla, Ramalingam Chellappa, and Abhinav Shrivastava. The pursuit of knowledge: Discovering and localizing novel categories using dual memory. 2021 IEEE/CVF International Conference on Computer Vision (ICCV), pages 9133-9143, 2021. 1, 2, 5, 6, 7, 8" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 514, + 287, + 577 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 514, + 287, + 577 + ], + "spans": [ + { + "bbox": [ + 48, + 514, + 287, + 577 + ], + "type": "text", + "content": "[35] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. In C. Cortes, N. D. Lawrence, D. D. Lee, M. Sugiyama, and R. Garnett, editors, Advances in Neural Information Processing Systems 28, pages 91-99. Curran Associates, Inc., 2015. 1, 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 578, + 287, + 631 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 578, + 287, + 631 + ], + "spans": [ + { + "bbox": [ + 48, + 578, + 287, + 631 + ], + "type": "text", + "content": "[36] Alvaro Collet Romea, Bo Xiong, Corina Gurau, Martial Hebert, and Siddhartha Srinivasa. Herbdisc: Towards lifelong robotic object discovery. In Proceedings of International Journal of Robotics Research (IJRR), January 2014. 1" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 632, + 287, + 696 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 632, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 48, + 632, + 287, + 696 + ], + "type": "text", + "content": "[37] Olga Russakovsky, Jia Deng, Hao Su, Jonathan Krause, Sanjeev Satheesh, Sean Ma, Zhiheng Huang, Andrej Karpathy, Aditya Khosla, Michael Bernstein, Alexander C. Berg, and Li Fei-Fei. ImageNet Large Scale Visual Recognition Challenge. International Journal of Computer Vision (IJCV), 115(3):211-252, 2015. 2, 9" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 696, + 287, + 707 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 696, + 287, + 707 + ], + "spans": [ + { + "bbox": [ + 48, + 696, + 287, + 707 + ], + "type": "text", + "content": "[38] Ville Satopaa, Jeannie Albrecht, David Irwin, and Barath" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 707 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 117 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 117 + ], + "type": "text", + "content": "Raghavan. Finding a \"kneedle\" in a haystack: Detecting knee points in system behavior. In 2011 31st International Conference on Distributed Computing Systems Workshops, pages 166-171, 2011. 7" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 117, + 545, + 159 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 117, + 545, + 159 + ], + "spans": [ + { + "bbox": [ + 307, + 117, + 545, + 159 + ], + "type": "text", + "content": "[39] Jianbo Shi and Jitendra Malik. Normalized cuts and image segmentation. Proceedings of IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 731-737, 1997. 2, 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 159, + 545, + 201 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 159, + 545, + 201 + ], + "spans": [ + { + "bbox": [ + 307, + 159, + 545, + 201 + ], + "type": "text", + "content": "[40] Jianping Shi, Qiong Yan, Li Xu, and Jiaya Jia. Hierarchical image saliency detection on extended cssd. IEEE Transactions on Pattern Analysis and Machine Intelligence, 38:717-729, 2016. 9" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 202, + 545, + 266 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 202, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 308, + 202, + 545, + 266 + ], + "type": "text", + "content": "[41] Oriane Simeoni, Gilles Puy, Huy V. Vo, Simon Roburin, Spyros Gidaris, Andrei Bursuc, Patrick Pérez, Renaud Marlet, and Jean Ponce. Localizing objects with self-supervised transformers and no labels. In Proceedings of the British Machine Vision Conference (BMVC), November 2021. 1, 2, 3, 4, 5, 6, 7, 8, 9" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 267, + 545, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 267, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 308, + 267, + 545, + 308 + ], + "type": "text", + "content": "[42] Krishna Kumar Singh, Utkarsh Ojha, and Yong Jae Lee. Finegan: Unsupervised hierarchical disentanglement for fine-grained object generation and discovery. In CVPR, 2019. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 309, + 545, + 363 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 309, + 545, + 363 + ], + "spans": [ + { + "bbox": [ + 308, + 309, + 545, + 363 + ], + "type": "text", + "content": "[43] J. Sivic, B. C. Russell, A. A. Efros, A. Zisserman, and W. T. Freeman. Discovering objects and their location in images. In Tenth IEEE International Conference on Computer Vision (ICCV'05) Volume 1, volume 1, pages 370-377 Vol. 1, Oct 2005. 1" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 363, + 545, + 395 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 363, + 545, + 395 + ], + "spans": [ + { + "bbox": [ + 308, + 363, + 545, + 395 + ], + "type": "text", + "content": "[44] T. G. Smith, G. D. Lange, and W. B. Marks. Fractal methods and results in cellular morphology — dimensions, lacunarity and multifractals, Nov. 1996. 4" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 396, + 545, + 449 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 396, + 545, + 449 + ], + "spans": [ + { + "bbox": [ + 308, + 396, + 545, + 449 + ], + "type": "text", + "content": "[45] Masato Tamura, Hiroki Ohashi, and Tomoaki Yoshinaga. Qpic: Query-based pairwise human-object interaction detection with image-wide contextual information. 2021 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 10405-10414, 2021. 1" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 449, + 545, + 482 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 449, + 545, + 482 + ], + "spans": [ + { + "bbox": [ + 308, + 449, + 545, + 482 + ], + "type": "text", + "content": "[46] J.R.R. Uijlings, K.E.A. van de Sande, T. Gevers, and A.W.M. Smeulders. Selective search for object recognition. International Journal of Computer Vision, 2013. 1, 5, 6, 7" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 482, + 545, + 545 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 482, + 545, + 545 + ], + "spans": [ + { + "bbox": [ + 308, + 482, + 545, + 545 + ], + "type": "text", + "content": "[47] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Proceedings of the 31st International Conference on Neural Information Processing Systems, NIPS'17, page 6000-6010, Red Hook, NY, USA, 2017. Curran Associates Inc. 1, 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 546, + 545, + 610 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 546, + 545, + 610 + ], + "spans": [ + { + "bbox": [ + 308, + 546, + 545, + 610 + ], + "type": "text", + "content": "[48] Huy V. Vo, Francis Bach, Minsu Cho, Kai Han, Yann LeCun, Patrick Pérez, and Jean Ponce. Unsupervised image matching and object discovery as optimization. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 8287-8296, 2019. 1, 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 611, + 545, + 654 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 611, + 545, + 654 + ], + "spans": [ + { + "bbox": [ + 308, + 611, + 545, + 654 + ], + "type": "text", + "content": "[49] Huy V. Vo, Patrick Pérez, and Jean Ponce. Toward unsupervised, multi-object discovery in large-scale image collections. In Proceedings of the European Conference on Computer Vision (ECCV), 2020. 5, 6, 7" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 654, + 545, + 696 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 654, + 545, + 696 + ], + "spans": [ + { + "bbox": [ + 308, + 654, + 545, + 696 + ], + "type": "text", + "content": "[50] Huy V. Vo, Elena Sizikova, Cordelia Schmid, Patrick Pérez, and Jean Ponce. Large-scale unsupervised object discovery. In Advances in Neural Information Processing Systems 34 (NeurIPS), 2021. 1, 2, 6, 7" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 696, + 545, + 707 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 696, + 545, + 707 + ], + "spans": [ + { + "bbox": [ + 308, + 696, + 545, + 707 + ], + "type": "text", + "content": "[51] Andrey Voynov, Stanislav Morozov, and Artem Babenko." + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "15833" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 406 + ], + "type": "list", + "angle": 0, + "index": 8, + "blocks": [ + { + "bbox": [ + 66, + 72, + 286, + 94 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 286, + 94 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 286, + 94 + ], + "type": "text", + "content": "Object segmentation without labels with large-scale generative models. In ICML, 2021. 9" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 95, + 287, + 148 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 95, + 287, + 148 + ], + "spans": [ + { + "bbox": [ + 48, + 95, + 287, + 148 + ], + "type": "text", + "content": "[52] Tiancai Wang, Tong Yang, Martin Danelljan, Fahad Shahbaz Khan, X. Zhang, and Jian Sun. Learning human-object interaction detection using interaction points. 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4115-4124, 2020. 1" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 148, + 287, + 201 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 148, + 287, + 201 + ], + "spans": [ + { + "bbox": [ + 48, + 148, + 287, + 201 + ], + "type": "text", + "content": "[53] Yangtao Wang, Xi Shen, Shell Xu Hu, Yuan Yuan, James Crowley, and Dominique Vaufreydaz. Self-supervised transformers for unsupervised object discovery using normalized cut. In Conference on Computer Vision and Pattern Recognition, 2022. 1, 2, 3, 5, 6, 7, 9" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 201, + 287, + 235 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 201, + 287, + 235 + ], + "spans": [ + { + "bbox": [ + 48, + 201, + 287, + 235 + ], + "type": "text", + "content": "[54] Zhongdao Wang, Liang Zheng, Yixuan Liu, and Shengjin Wang. Towards real-time multi-object tracking. The European Conference on Computer Vision (ECCV), 2020. 1" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 234, + 287, + 276 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 234, + 287, + 276 + ], + "spans": [ + { + "bbox": [ + 48, + 234, + 287, + 276 + ], + "type": "text", + "content": "[55] Peter Welinder, Steve Branson, Takeshi Mita, Catherine Wah, Florian Schroff, Serge Belongie, and Pietro Perona. Caltech-ucsd birds 200. Technical Report CNS-TR-201, Caltech, 2010. 9" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 276, + 287, + 319 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 276, + 287, + 319 + ], + "spans": [ + { + "bbox": [ + 48, + 276, + 287, + 319 + ], + "type": "text", + "content": "[56] Nicolai Wojke, Alex Bewley, and Dietrich Paulus. Simple online and realtime tracking with a deep association metric. In 2017 IEEE International Conference on Image Processing (ICIP), pages 3645-3649. IEEE, 2017. 1" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 319, + 287, + 363 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 319, + 287, + 363 + ], + "spans": [ + { + "bbox": [ + 48, + 319, + 287, + 363 + ], + "type": "text", + "content": "[57] Danfei Xu, Yuke Zhu, Christopher Bongsoo Choy, and Li Fei-Fei. Scene graph generation by iterative message passing. 2017 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3097-3106, 2017. 1" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 363, + 287, + 406 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 363, + 287, + 406 + ], + "spans": [ + { + "bbox": [ + 48, + 363, + 287, + 406 + ], + "type": "text", + "content": "[58] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable " + }, + { + "bbox": [ + 48, + 363, + 287, + 406 + ], + "type": "inline_equation", + "content": "\\{\\mathrm{detr}\\}" + }, + { + "bbox": [ + 48, + 363, + 287, + 406 + ], + "type": "text", + "content": ": Deformable transformers for end-to-end object detection. In International Conference on Learning Representations, 2021. 5" + } + ] + } + ], + "index": 7 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15834" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 11 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/844d9362-4725-44da-8709-8687e3c64eb2_content_list.json b/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/844d9362-4725-44da-8709-8687e3c64eb2_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..89fb8613a147b60f5f18df5cb49abd6988c6e6d2 --- /dev/null +++ b/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/844d9362-4725-44da-8709-8687e3c64eb2_content_list.json @@ -0,0 +1,1856 @@ +[ + { + "type": "text", + "text": "MPCViT: Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention", + "text_level": 1, + "bbox": [ + 171, + 128, + 799, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Wenxuan Zeng $^{1}$ Meng Li $^{1*}$ Wenjie Xiong $^{2}$ Tong Tong $^{1}$ Wen-jie Lu $^{3}$ Jin Tan $^{3}$ Runsheng Wang $^{1}$ Ru Huang $^{1}$ $^{1}$ Peking University $^{2}$ Virginia Tech $^{3}$ Ant Group", + "bbox": [ + 184, + 200, + 779, + 257 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{zwx.andy,tongtong}@stu.pku.edu.cn, {meng.li,wrs,ruhuang}@pku.edu.cn, wenjiex@vt.edu, {juhou.lwj,tanjin.tj}@antgroup.com", + "bbox": [ + 181, + 258, + 785, + 292 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 325, + 313, + 343 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Secure multi-party computation (MPC) enables computation directly on encrypted data and protects both data and model privacy in deep learning inference. However, existing neural network architectures, including Vision Transformers (ViTs), are not designed or optimized for MPC and incur significant latency overhead. We observe Softmax accounts for the major latency bottleneck due to a high communication complexity, but can be selectively replaced or linearized without compromising the model accuracy. Hence, in this paper, we propose an MPC-friendly ViT, dubbed MPCViT, to enable accurate yet efficient ViT inference in MPC. Based on a systematic latency and accuracy evaluation of the Softmax attention and other attention variants, we propose a heterogeneous attention optimization space. We also develop a simple yet effective MPC-aware neural architecture search algorithm for fast Pareto optimization. To further boost the inference efficiency, we propose MPCViT $^+$ , to jointly optimize the Softmax attention and other network components, including GeLU, matrix multiplication, etc. With extensive experiments, we demonstrate that MPCViT achieves $1.9\\%$ , $1.3\\%$ and $3.6\\%$ higher accuracy with $6.2\\times$ , $2.9\\times$ and $1.9\\times$ latency reduction compared with baseline ViT, MPCFormer and THE-X on the Tiny-ImageNet dataset, respectively. MPCViT $^+$ further achieves a better Pareto front compared with MPCViT. The code and models for evaluation are available at https://github.com/PKU-SEC-Lab/mpcvit.", + "bbox": [ + 75, + 358, + 473, + 767 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 792, + 209, + 809 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "As machine learning models are handling increasingly sensitive data and tasks, privacy has become one of the major concerns during the model deployment. Secure multi-party computation (MPC) [14] can protect the privacy of", + "bbox": [ + 75, + 818, + 470, + 881 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/51f3964077c43d86aff9aa56b9faab1fc634fd7c6f3e242b9d1b85dac77fb754.jpg", + "image_caption": [ + "Figure 1. The latency breakdown of a Transformer block w.r.t (a) # heads and (b) # tokens; and (c) the relative error of Softmax and ReLU Softmax with different input variances." + ], + "image_footnote": [], + "bbox": [ + 503, + 325, + 638, + 434 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/8924f7f556a5fe338742235b27bb24aa1a5e9cf97969c134f67c403abe275b0b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 638, + 325, + 772, + 434 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/12b0bc74a33f1db51d5dc8d51a6897463daac312638274cf9415baa3cc7c74fd.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 772, + 325, + 890, + 434 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "both data and deep neural network (DNN) models and has gained a lot of attention in recent years [42, 51, 60].", + "bbox": [ + 496, + 506, + 890, + 536 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "However, existing DNN architectures, especially the recently proposed Vision Transformers (ViTs) [2, 11, 64], are not designed or optimized for MPC (the high-level private ViT inference framework in MPC is shown in Figure 2 and Appendix A.1). Although ViTs have achieved superior performance for various vision tasks [2, 15, 16, 64], they face several realistic limitations when directly deployed in MPC: 1) communication overhead: in contrast to regular inference on plaintext, operations like Softmax, GeLU, max, etc, require intensive communication in MPC, which usually dominates the total inference latency [42, 60]. For example, Softmax is usually very lightweight in plaintext inference. However, as shown in Figure 1(a) and Figure 1(b), it accounts for the majority of the Transformer inference latency due to the high communication complexity; 2) approximation error: operations like exponential, tanh, reciprocal, etc, cannot be computed directly and require iterative approximation, limiting the computation accuracy. For instance, as shown in Figure 1(c), the relative error of Softmax significantly increases when the input variance is large due to its narrow dynamic range [60]. In contrast, replacing exponential in Softmax with ReLU reduces the relative error drastically (denoted as ReLU Softmax in §2.2).", + "bbox": [ + 496, + 537, + 892, + 883 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Numerous efficient Transformer variants have been pro", + "bbox": [ + 517, + 885, + 890, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding author.", + "bbox": [ + 94, + 887, + 220, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "5052", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/34002c189cff84ca15fb9c50cf7a5479470d1d7120442c1472bf183e373513f0.jpg", + "image_caption": [ + "Figure 2. An overall illustration of private Vision Transformer inference in the MPC framework." + ], + "image_footnote": [], + "bbox": [ + 122, + 90, + 851, + 224 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "posed in recent years [5, 29, 49, 58]. Linear Transformers, including Linformer [58], cosFormer [49], Reformer [29], etc, reduce the quadratic computation complexity of the attentions and significantly accelerate model inference for long sequences. However, these Transformer optimizations have primarily focused on reducing the network computation. Hence, they either retain complex non-linear functions or still require iterative approximation, both resulting in intensive communication overhead in MPC. Recently, MPC-Former [33] and THE-X [6] are proposed to improve the inference efficiency of BERT [28] in MPC. MPCFormer simplifies Softmax by replacing exponential with a more MPC-friendly quadratic operation while THE-X approximates Softmax with a small estimation network. However, their attention variants is not flexible and can still be too expensive for certain latency constraints. Moreover, the network-level optimization suffers from a large accuracy degradation when directly applied to vision tasks.", + "bbox": [ + 75, + 265, + 472, + 537 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this work, we first breakdown Softmax into more atomic operations and analyze their impact on the inference accuracy and efficiency, based on which we propose and compare a set of attention variants comprehensively. The comparison enables us to find MPC-friendly attention variants, which are either highly accurate or highly efficient. We further observe not all attentions are equally important within a ViT. Based on these observations, we propose the first MPC-friendly ViT architecture, dubbed MPCViT. MPCViT features a heterogeneous attention design space to explore the trade-off between accuracy and efficiency, and an MPC-aware differentiable neural architecture search (NAS) algorithm for effective Pareto optimization. Our contributions can be summarized as follows:", + "bbox": [ + 75, + 539, + 468, + 750 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We breakdown Softmax and reveal the impact of atomic operations on the inference accuracy and efficiency, based on which a heterogeneous attention design space is proposed.", + "- We propose an effective MPC-aware differentiable NAS algorithm to explore the attention design space based on real latency measurements instead of proxies. To the best of our knowledge, we make the first" + ], + "bbox": [ + 94, + 763, + 470, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "attempt to introduce the MPC-aware NAS to optimize ViT inference in MPC.", + "bbox": [ + 529, + 265, + 890, + 295 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- Our MPC-friendly ViT model family, MPCViT, outperforms prior-art models in MPC in terms of both accuracy and efficiency. MPCViT achieves $1.9\\%$ and $1.3\\%$ higher accuracy with $6.2\\times$ and $2.9\\times$ latency reduction compared with baseline ViT and MPCFormer on Tiny-ImageNet dataset, respectively.", + "- We further extend MPCViT to optimize other Transformer components simultaneously with Softmax, named $\\mathrm{MPCViT}^+$ , achieving an even better Pareto front compared with MPCViT." + ], + "bbox": [ + 517, + 305, + 890, + 467 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Preliminaries and Related Works", + "text_level": 1, + "bbox": [ + 500, + 479, + 803, + 496 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. ViT and Efficient Attention", + "text_level": 1, + "bbox": [ + 500, + 505, + 746, + 520 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "ViT architecture. ViT [11] has demonstrated a great potential to capture the long-range visual dependencies. It takes image patches as input and is composed of an input projection layer, a stack of Transformer layers, and a task-specific multi-layer perceptron (MLP) head. Each layer consists of a multi-head attention (MHA) layer and an MLP block. The core computation is the Softmax attention:", + "bbox": [ + 496, + 527, + 890, + 635 + ], + "page_idx": 1 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {A t t e n t i o n} (Q, K, V) = \\operatorname {S o f t m a x} \\left(\\frac {Q K ^ {T}}{\\sqrt {d _ {k}}}\\right) V,\n$$\n", + "text_format": "latex", + "bbox": [ + 549, + 643, + 841, + 680 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "where $Q, K, V$ are queries, keys and values, respectively. $d_{k}$ denotes the embedding dimension of each key, and Softmax normalizes the attention map. The detailed explanation of ViT architecture is shown in Figure 2 and Appendix A.2.", + "bbox": [ + 496, + 688, + 890, + 750 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Linear attention. Linear attention has been widely studied in previous works [5, 29, 38, 49]. These works aim at reducing the quadratic increase of compute and memory by leveraging special kernel functions. Different kernel functions have been proposed in existing works [4, 49, 53, 58]. UFO-ViT [53] proposes to use $\\ell 2$ -Norm as the kernel function while CosFormer [49] leverages the cosine distance kernel. Linformer [58] approximates self-attention by a low-rank matrix. Hydra Attention [4] proposes to use as many heads as possible to further reduce the computation", + "bbox": [ + 496, + 750, + 890, + 901 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "5053", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "table", + "img_path": "images/bc13a5cd666ec5d9da0383f1e0fd08c8b35dfdff71cc9dc1126ee1bf53d86839.jpg", + "table_caption": [ + "Table 1. Comparison among existing network optimizations for the efficient private inference." + ], + "table_footnote": [], + "table_body": "
MethodModelTechniqueOptimized ComponentGranularityLinear Fusion
Delphi [42]CNNReLU-aware NASReLULayerX
DeepReDuce [25]CNNManually removalReLULayerX
CryptoNAS [13]CNNReLU-aware NASReLULayerX
SNL [8]CNNReLU-aware NASReLUChannel, pixelX
Sphinx [7]CNNBlock-level NASReLUBlockX
SENet [31]CNNSensitivity-aware alloc.ReLULayer, pixelX
RRNet [48]CNNHardware-aware NASReLULayerX
DeepReShape [26]CNNReLU-equalizationReLUStageX
SAFENet [31]CNNMixed-precision poly. approx.ReLUChannelX
THE-X [6]BERTPolynomial approx.GeLU, Softmax, LayerNormNetworkX
MPCFormer [33]BERTPolynomial approx.Softmax, GeLUNetworkX
MPCViT (ours)ViTMPC-aware NASSoftmaxLayer, head, rowX
Heterogeneous attention
MPC-aware NAS
MPCViT+ (ours)ViTHeterogeneous attentionSoftmax, GeLU, MatMulLayer, head, row, token✓
GeLU linearization
Linear fusion
", + "bbox": [ + 117, + 101, + 854, + 327 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "complexity of the linear attention. However, these works primarily focus on reducing the network computation rather than the communication overhead and are not beneficial for ViT inference in MPC.", + "bbox": [ + 75, + 352, + 468, + 412 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Non-local neural networks and Scaling attention. [59] presents a generic non-local operation to capture long-range dependencies. The formulation is defined as $\\frac{1}{\\mathcal{C}(x)}\\sum_{\\forall j}f(x_i,x_j)g(x_j)$ , where $x$ denotes the input feature map and $f(\\cdot)$ is a similarity function, e.g., cosine or Euclidean distance. $g(\\cdot)$ computes a certain input representation, and $\\mathcal{C}(x)$ is a normalization factor. By setting $f(\\cdot)$ as the dot-product similarity and $\\mathcal{C}(x) = n$ , where $n$ is the sequence length, we get an attention variant, named Scaling Attention (ScaleAttn). ScaleAttn is an extremely simple attention and only involves linear operations like multiplication and addition. ScaleAttn can be further reparameterized to accelerate computation1 as below:", + "bbox": [ + 75, + 417, + 472, + 617 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {S c a l e A t t n} (Q, K, V) = \\frac {1}{n} (Q K ^ {T}) V = \\frac {Q}{\\sqrt {n}} (\\frac {K ^ {T}}{\\sqrt {n}} V).\n$$\n", + "text_format": "latex", + "bbox": [ + 96, + 633, + 447, + 667 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Multi-Party Computation", + "text_level": 1, + "bbox": [ + 76, + 686, + 310, + 705 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "MPC [14] is a cryptographic technique that offers a promising solution to protect the privacy of both data and model during deep learning inference. Appendix B depicts the cryptographic primitives for MPC, including Secret Sharing, Oblivious Transfer and Garble Circuit. [14] proposes an efficient MPC protocol for addition and multiplication. [44] proposes efficient two-party computation protocols for various arithmetic operations and approximations for non-linear functions in DNN. For example, [44]", + "bbox": [ + 75, + 714, + 468, + 853 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "approximates Softmax with ReLU Softmax, i.e.,", + "bbox": [ + 500, + 353, + 820, + 369 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {R e L U S o f t m a x} (x) = \\frac {\\operatorname {R e L U} (x _ {i})}{\\sum_ {i} \\operatorname {R e L U} (x _ {i}) + \\epsilon},\n$$\n", + "text_format": "latex", + "bbox": [ + 555, + 376, + 836, + 411 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\epsilon$ is a very small value to avoid the zero denominator. ABY3 [43] is proposed to enable efficient conversion between different secret sharing schemes in three-party computation. Delphi [42] develops a hybrid MPC protocol and optimizes the network to explore the performance-accuracy trade-off. Iron [18] proposes a set of protocols to reduce the communication overhead of matrix-matrix multiplications (MatMuls), LayerNorm, etc for Transformer-based models.", + "bbox": [ + 496, + 417, + 890, + 537 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Although MPC protocols have been improved significantly in recent years, DNN inference in MPC still suffers from intensive communication and latency overhead compared to the plaintext inference. To reduce the latency, different algorithms have been proposed to optimize convolutional NNs (CNNs) with a focus on ReLU. We compare the important characteristics of our methods with existing related work in Table 1. SNL [8] and DeepReduce [25] propose to remove ReLUs and linearize a subset of neurons selectively. SAFENet [37], Delphi [42], RRNet [48] and PolyMPCNet [47] replace ReLUs with polynomial functions that are more MPC-friendly via NAS for CNNs. Sphynx [7] further develops an MPC-friendly architecture search space for CNNs and leverages NAS to optimize the accuracy given different latency constraints. However, these works mainly focus on the ReLU counts in CNNs, and accelerating ViTs with latency consideration is still a challenge. MPCFormer [33] and THE-X [6] recently propose to replace Softmax with more MPC-friendly operations for BERT, but the network-level method incurs limited latency reduction and a large accuracy degradation. As shown in Table 1, our work proposes an MPC-aware NAS to explore a fined-grained heterogeneous attention optimization space, and further presents a GeLU linearization", + "bbox": [ + 496, + 537, + 892, + 902 + ], + "page_idx": 2 + }, + { + "type": "page_footnote", + "text": "1In this work, we do not focus on computational overhead in MPC since communication dominates the overhead.", + "bbox": [ + 76, + 875, + 468, + 898 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "5054", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "table", + "img_path": "images/5eb3ce17d4660ea1bc3780de17a38f1c1319b3cad996d1740e9bd38809eec1cf.jpg", + "table_caption": [ + "Table 2. Top-1 accuracy and latency comparison of different attention variants on CIFAR-10. The rows in grey are attention variants with the lowest latency and the highest accuracy, respectively. We also show the properties and remaining operations of each variant." + ], + "table_footnote": [], + "table_body": "
Attention VariantMonotonicityNon-negativityNormalizationExponentialMaxReciprocalAcc. (%)Lat. (s)
Softmax Attention [11]✓✓✓✓✓✓92.696.82
Linformer Attention [58]✓✓✓✓✓✓90.855.44
ReLU Attention✓✓✗✗✓✗failfail
ReLU6 Attention✓✓✗✗✓✗90.503.02
Sparsemax Attention [40]✓✓✗✗✓✗91.233.23
XNorm Attention [53]✓✗✗✗✗✓91.2413.25
Square Attention✗✓✗✗✗✗91.270.72
2Quad Attention [33]✗✓✓✗✗✓91.864.22
Scaling Attention (ScaleAttn) [59]✓✗✗✗✗✗91.520.66
ReLU Softmax Attention (RSAAttn) [44]✓✓✓✗✓✓92.315.32
", + "bbox": [ + 104, + 114, + 866, + 250 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/47634366d0c7d64767a1c148d641e59259a3bb4fff777524082ae8e284452b38.jpg", + "image_caption": [ + "Figure 3. (a) Latency breakdown of a 4-head ViT with 256 hidden dimension and 65 tokens on CIFAR-10 dataset; (b) latency breakdown of Softmax. Both (a) and (b) consist of SEMI-2K (outside) and Cheetah (inside) protocols." + ], + "image_footnote": [], + "bbox": [ + 81, + 270, + 467, + 409 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "technique to reduce the latency of MLP.", + "bbox": [ + 76, + 494, + 341, + 508 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3. Motivating Inspiration of MPCViT", + "text_level": 1, + "bbox": [ + 76, + 525, + 395, + 542 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In this section, we breakdown Softmax for accuracy and efficiency evaluation and compare two ways of building MPC-friendly ViTs. The analysis serves as our motivation of proposing MPCViT, which features heterogeneous attention and NAS-based Pareto optimization.", + "bbox": [ + 75, + 551, + 468, + 628 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Motivation 1: ViT latency bottleneck in MPC. In Figure 1, we profile the latency of a Transformer block with different number of heads and tokens. We now further dive into Softmax and evaluate its latency breakdown. We profile a 4-head ViT with 65 tokens and 256 hidden dimension assuming the WAN setting as defined in §5.1. We consider two widely used protocols, including SEMI-2K [9] and Cheetah [22]. From both Figure 1 and Figure 3, we make the following observations: 1) Softmax is the major latency bottleneck in most cases. The latency of GeLU and MatMuls also becomes non-negligible when the number of heads or tokens is small; 2) Softmax mainly involves three operations, including exponential, reciprocal and max. All of the operations are important for the latency overhead. Therefore, we are motivated to get rid of these expensive operations as many as possible, and we propose to first focus on optimizing the Softmax and only consider GeLU and MatMul when the number of heads or tokens is small.", + "bbox": [ + 75, + 628, + 470, + 900 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Motivation 2: comparison of different attention variants. To reduce the latency of Softmax in the attention module, there are two different ways, i.e., 1) reducing the dimension of $QK^T$ such as Linformer [58], which approximates $QK^T$ with a low rank matrix; and 2) simplifying Softmax by replacing exponential, reciprocal or max with other operations. For the second method, while the possible activation variants can be abundant, we observe the following three important properties of Softmax, which helps us to select promising candidates: monotonicity, non-negativity, and normalized sum to 1. The first two properties are related to the exponential while the last one is achieved with reciprocal. We propose and evaluate the following variants, including ReLU, ReLU6, Sparsemax [40], XNorm [53], Square, Scaling [59], 2Quard [33], Linformer [58] and ReLU Softmax [44]. We define the attention with ReLU Softmax as RSAttn for short. The formulation of these attention variants is described in Appendix C.", + "bbox": [ + 496, + 273, + 890, + 547 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To compare these attention variants, we train each model for 300 epochs on CIFAR-10 and compare the latency, accuracy, remaining operations, and how they satisfy the properties of Softmax in Table 2. We make the following observations: 1) Attention with more expensive operations can be more inefficient. For instance, 2Quad has an extra reciprocal compared with Square such that 2Quad suffers from a higher latency; 2) Linformer suffers from a high accuracy degradation ( $\\sim 1.8\\%$ compared with Softmax attention) as it significantly reduces the matrix dimensions such that the model learning capability is degraded, and the computation reduction of this optimization cannot benefit latency reduction a lot. Hence, the first method is not preferred; 3) ReLU Softmax and 2Quad achieve higher accuracy among other variants and we hypothesize this is because they both normalize the sum to 1, which is realized with reciprocal and also leads to relatively higher latency. ReLU Softmax is more preferred over Softmax and 2Quad due to its small approximation error and small accuracy degradation; 4) Scaling is equivalent to directly removing the Softmax. Although it is the fastest, directly linearizing all the Softmax leads to a large accuracy degradation; 5) it is interesting to notice that although XNorm attention has linear com", + "bbox": [ + 496, + 551, + 892, + 902 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "5055", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "putation, it incurs the highest latency because computing $\\ell 2$ -norm involves both reciprocal and square root, both of which are expensive in MPC.", + "bbox": [ + 76, + 90, + 468, + 135 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Motivation 3: Not all attentions are equally important. As observed in [5, 36, 41, 46, 54, 56], not all attentions are equally important and different layer prefers different attention type. For instance, [46] identifies the minor contribution of the early attention layers in recent ViTs, while [34] demonstrates the second head shows higher importance than other heads. Thus, the importance of attentions among different layers or even the attentions within the same layer can be different. It indicates we can safely replace the expensive Softmax or ReLU Softmax with the cheaper Scaling without compromising the network accuracy.", + "bbox": [ + 75, + 136, + 467, + 301 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Remark The analysis above provides us with the following intuitions when designing an MPC-friendly ViT:", + "bbox": [ + 76, + 301, + 467, + 333 + ], + "page_idx": 4 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1) ReLU Softmax is more preferred over Softmax and more MPC-friendly, and Scaling has the highest inference efficiency;", + "2) by selectively replacing the ReLU Softmax with the cheaper Scaling, it is possible to reduce the inference latency without compromising the inference accuracy;", + "3) when the latency of GeLU and Softmax are comparable, we have an opportunity to further simplify GeLU along with Softmax." + ], + "bbox": [ + 86, + 338, + 467, + 488 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. The Proposed MPCViT Algorithm", + "text_level": 1, + "bbox": [ + 76, + 497, + 388, + 513 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In this section, we introduce MPCViT, which for the first time optimizes the ViT architecture with NAS-based algorithm for a fast private inference in MPC.", + "bbox": [ + 76, + 523, + 467, + 568 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Overview of Optimization Flow", + "text_level": 1, + "bbox": [ + 76, + 575, + 352, + 590 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Based on the motivations described above, we now describe our MPC-aware ViT optimization flow as shown in Figure 4. We propose to replace the Softmax with the accurate yet MPC-friendly ReLU Softmax in the ViT first and then, linearize the relatively \"unimportant\" ReLU Softmax with efficient Scaling. To find the \"unimportant\" ReLU Softmax, we first design a heterogeneous search space that includes both ReLU Softmax and Scaling attentions. Architecture parameters are defined to measure the importance of ReLU Softmax and enable the selection between the two attention variants with different structure granularities (§4.2). Then, we propose an MPC-aware differentiable NAS algorithm to learn the architecture parameters and model parameters simultaneously. We select between the attention variants based on the architecture parameters and the latency constraints (§4.3). In the last step, we retrain the ViT with heterogeneous attentions from scratch. We leverage knowledge distillation (KD) to improve the accuracy of the searched networks (§4.4). Appendix D depicts the complete algorithm flow of MPCViT.", + "bbox": [ + 75, + 598, + 467, + 900 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/698fe7e2af04aca536d4b0f02fcfcdc169a001e5e04c3922111a38767c9a25e7.jpg", + "image_caption": [ + "Figure 4. Overview of our proposed MPCViT pipeline." + ], + "image_footnote": [], + "bbox": [ + 504, + 90, + 888, + 258 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Heterogeneous Attention Search Space", + "text_level": 1, + "bbox": [ + 500, + 296, + 831, + 313 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Our heterogeneous search space combines two candidate attention variants, i.e., MPC-efficient ScaleAttn and high-accuracy RSAAttn and has the following three different structural granularities as shown in Figure 5:", + "bbox": [ + 498, + 320, + 890, + 380 + ], + "page_idx": 4 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- Layer-wise search space is coarse-grained, with each layer using either ScaleAttn or RSAattn. The total number of possible architectures in the search space can be limited, especially for shallow ViT models.", + "- Head-wise search space selects ScaleAttn or RSAAttn for each attention head of each layer.", + "- Row-wise search space (i.e., token-wise) is the most fine-grained and mixes the two attention variants along each row of the attention map." + ], + "bbox": [ + 517, + 386, + 890, + 539 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Though the search spaces have different granularities, they share very similar NAS formulation. In the rest of the explanation, we will use the head-wise search space as an example to explain our algorithm.", + "bbox": [ + 498, + 546, + 888, + 606 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.3. MPC-Aware Differentiable NAS", + "text_level": 1, + "bbox": [ + 500, + 614, + 782, + 628 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Many research efforts have been made to NAS including reinforcement learning method (RL) [17, 24, 57], however, RL-based NAS requires significant overhead during searching. Recent years, [10, 27, 55, 61] explore hardware-aware NAS algorithms to make model fit the rigorous hardware requirement. For private ViT inference, we also need a NAS algorithm that takes MPC conditions into consideration.", + "bbox": [ + 496, + 637, + 890, + 742 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Given the heterogeneous attention search space, we now introduce our simple yet effective MPC-aware differentiable NAS algorithm.", + "bbox": [ + 496, + 743, + 888, + 787 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Search formulation. Inspired by [5], we introduce an architecture parameter $\\alpha$ ( $0 \\leq \\alpha \\leq 1$ ) for each head, which is an auxiliary learnable variable that helps to choose between RSAAtt and ScaleAttn. Then, each head implements the computation below:", + "bbox": [ + 496, + 787, + 890, + 863 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\alpha \\cdot \\operatorname {R e L U S o f t m a x} \\left(\\frac {Q K ^ {T}}{\\sqrt {d _ {k}}}\\right) V + (1 - \\alpha) \\cdot \\frac {\\operatorname {S c a l e A t t n} (Q , K , V)}{\\sqrt {d _ {k}}}.\n$$\n", + "text_format": "latex", + "bbox": [ + 500, + 869, + 893, + 905 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "5056", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/ffe906ef0c4c3f9cf186366397d0781739333ecc01c993cf203d5dfc4821633a.jpg", + "image_caption": [ + "Figure 5. An illustration of our proposed search space with different structure granularities: (a) layer-wise search space with the size of $2^{\\# \\text{layers}}$ ; (b) head-wise search space with the size of $2^{\\# \\text{layers} \\times \\# \\text{heads}}$ and; (c) row-wise search space with the size of $2^{\\# \\text{layers} \\times \\# \\text{heads} \\times \\# \\text{tokens}}$ . The blocks in blue represent RSAAttn and the blocks in grey represent ScaleAttn." + ], + "image_footnote": [], + "bbox": [ + 80, + 88, + 467, + 233 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Note that we also add $\\frac{1}{\\sqrt{d_k}}$ for ScaleAttn to make the search process more stable and robust.", + "bbox": [ + 76, + 344, + 468, + 375 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Search objective function. We aim at training ViTs with high accuracy but as few RSAattn as possible. We introduce $\\ell 1$ -penalty into the objective function and formulate the NAS as a one-level optimization problem. To take MPC overhead into consideration, we incorporate realistic inference latency constraints into objective function to construct the MPC-aware NAS algorithm as", + "bbox": [ + 75, + 376, + 468, + 482 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {C o s t} (\\alpha_ {i j}) = \\alpha_ {i j} \\cdot \\mathrm {L a t (A T T N} _ {i j}),\n$$\n", + "text_format": "latex", + "bbox": [ + 156, + 494, + 387, + 512 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\min _ {\\theta , \\alpha} \\ell (f _ {\\theta , \\alpha} (x), y) + \\lambda \\cdot (\\sum_ {i = 1} ^ {L} \\sum_ {j = 1} ^ {N} \\| \\operatorname {C o s t} (\\alpha_ {i j}) \\| _ {1}),\n$$\n", + "text_format": "latex", + "bbox": [ + 114, + 515, + 431, + 556 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $x$ and $y$ are the input-label pairs, $\\ell(\\cdot)$ is the loss function, $\\lambda$ is a hyper-parameter to control the weight of inference overhead, $N$ is the number of heads in one layer, and $L$ is the number of layers. $\\| \\cdot \\|_1$ means $\\ell 1$ -norm, and $\\mathrm{ATTN}_{ij}$ means the candidate attention of $i$ -th layer and $j$ -th head. We initialize $\\alpha$ for each head to 1.0 and jointly optimize the network parameter $\\theta$ and architecture parameter $\\alpha$ during searching. Note that our differentiable algorithm computes the gradients of $\\alpha$ for all the attention heads across different layers in ViT simultaneously.", + "bbox": [ + 75, + 568, + 468, + 718 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Architecture parameter binarization. After the network searching, we obtain $\\alpha$ for each attention head in all layers. To select either RSAattn or ScaleAttn for each head, we binarize $\\alpha$ based on the following rule: we use the top- $k$ rule according to the ratio of RSAattn budgeet $\\mu$ , which is defined as $\\# \\text{RSAattn} / \\# \\text{Heads}$ . Specifically, we first find the $\\mu L N$ -th largest $\\alpha$ , denoted as $\\alpha^{*}$ , and then we binarize $\\alpha$ for each attention head following $\\mathbb{1}(\\alpha \\geq \\alpha^{*})$ . Our proposed search method does not need to train candidate networks, but only needs to train once and then select, which accelerates our search process. Now, we obtain a heterogeneous ViT, and by changing $\\mu$ , we can obtain a family of", + "bbox": [ + 75, + 719, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/af21e0dc47712bcf343889eb7b92c595f0a6d63eb1b0d8a92516e29847a27dc0.jpg", + "image_caption": [ + "Figure 6. MPCViT+: The optimization of our proposed GeLU linearization and linear fusion for the MLP block." + ], + "image_footnote": [], + "bbox": [ + 501, + 90, + 890, + 212 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "ViTs with different accuracy and efficiency trade-off.", + "bbox": [ + 500, + 265, + 849, + 280 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.4. Train the Searched ViT for Better Performance", + "text_level": 1, + "bbox": [ + 500, + 291, + 890, + 306 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "After binarization, RSAattn with a small $\\alpha$ are replaced with ScaleAttn. We find that directly training a heterogeneous ViT results in an accuracy drop. So, how to effectively train the heterogeneous ViT and restore the model accuracy is an important question for us.", + "bbox": [ + 496, + 314, + 890, + 388 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Token-wise feature-based KD. KD [21] is a powerful tool for a student network to learn from a teacher network, which is usually larger and more complex with a higher learning capacity. To improve the accuracy of MPCViT, we leverage token-wise feature-based self-distillation along with a logits-based KD, which uses the baseline ViT as the teacher network while other larger networks can be easily plugged in and used in our framework. For the feature-based KD, we take the output features of the last ViT layer from both the student and the teacher networks and compute the $\\ell 2$ -distance, denoted as $\\mathcal{L}_{\\text {feature }}$ . We also use KL-divergence loss $\\mathcal{L}_{KL}$ for the logits-based KD, denoted as $\\mathcal{L}_{\\text {logits }}$ . Combining distillation loss with the task-specific cross-entropy (CE) loss $\\mathcal{L}_{CE}$ , we obtain the final training objective under a distillation temperature $\\mathcal{T}$ as follows:", + "bbox": [ + 496, + 390, + 892, + 617 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {L} _ {\\text {t r a i n}} = \\chi \\mathcal {L} _ {C E} + \\beta \\mathcal {L} _ {\\text {l o g i t s}} + \\gamma \\mathcal {L} _ {\\text {f e a t u r e}} \\\\ = \\chi \\mathcal {L} _ {C E} + \\beta \\mathcal {L} _ {K L} (\\sigma (\\frac {z _ {s}}{\\mathcal {T}}), \\sigma (\\frac {z _ {t}}{\\mathcal {T}})) + \\gamma \\| z _ {s} - z _ {t} \\| _ {2}, \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 504, + 628, + 885, + 676 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $\\chi, \\beta$ and $\\gamma$ are training hyper-parameters to balance different loss functions in the training objective, $z_{s}$ and $z_{t}$ are feature maps from student and teacher, and $\\sigma$ is Softmax. This self-distillation requires no extra model and only introduces negligible training cost, and has no influence on inference latency or communication overhead in MPC.", + "bbox": [ + 496, + 685, + 890, + 776 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.5. MPCViT+: Support for GeLU Linearization", + "text_level": 1, + "bbox": [ + 500, + 786, + 877, + 801 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The above design of MPCViT leverages NAS algorithm to build the efficient yet effective attention mechanism. Besides attention, in MLP blocks, non-linear GeLU also impacts the communication cost in some protocols, e.g., Cheetah when the number of heads or tokens is small. And two linear layers near GeLU are also costly because", + "bbox": [ + 496, + 809, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "5057", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "the inverted-bottleneck structure of MLP leads to high-dimensional MatMul, which is shown in Figure 1 and Figure 3(a). To further improve the efficiency of ViTs, we propose an extended version called MPCViT+. Specifically, MPCViT+ searches and removes relatively \"unimportant\" GeLUs. Given architecture parameter $\\beta$ for GeLU, the NAS algorithm is similar to the attention optimization:", + "bbox": [ + 75, + 90, + 472, + 196 + ], + "page_idx": 6 + }, + { + "type": "equation", + "text": "\n$$\n(\\beta \\cdot \\operatorname {G e L U} (x) + (1 - \\beta) \\cdot x) \\cdot \\mathscr {W}.\n$$\n", + "text_format": "latex", + "bbox": [ + 158, + 208, + 387, + 224 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "The architecture parameters $\\alpha$ and $\\beta$ are jointly learnt during the search, thus the NAS loss is defined along with the classification loss $\\min_{\\theta ,\\alpha ,\\beta}\\ell (f_{\\theta ,\\alpha ,\\beta}(x),y)$ ..", + "bbox": [ + 76, + 234, + 468, + 287 + ], + "page_idx": 6 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {C o s t} \\left(\\beta_ {i j}\\right) = \\beta_ {i j} \\cdot \\operatorname {L a t} \\left(\\operatorname {A c t} _ {i j}\\right),\n$$\n", + "text_format": "latex", + "bbox": [ + 171, + 299, + 375, + 316 + ], + "page_idx": 6 + }, + { + "type": "equation", + "text": "\n$$\n\\lambda \\cdot (\\sum_ {i = 1} ^ {L} \\sum_ {j = 1} ^ {N} \\| \\operatorname {C o s t} \\left(\\alpha_ {i j}\\right) \\| _ {1}) + \\eta \\cdot (\\sum_ {i = 1} ^ {L} \\sum_ {j = 1} ^ {T} \\| \\operatorname {C o s t} \\left(\\beta_ {i j}\\right) \\| _ {1}),\n$$\n", + "text_format": "latex", + "bbox": [ + 83, + 319, + 460, + 361 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "here, we take token-wise linearization as an example, and $\\mathrm{Lat}(\\mathrm{Act}_{\\mathrm{ij}})$ denotes the latency of either GeLU or identity of $i$ -th layer and $j$ -th token, $T$ denotes the number of tokens in each layer. We can consider the balance between $\\lambda$ and $\\eta$ through the private inference latency: $\\frac{\\lambda}{\\eta} = \\frac{\\mathrm{Lat}(\\mathrm{ATTN})}{\\mathrm{Lat}(\\mathrm{GELU})}$ .", + "bbox": [ + 76, + 371, + 468, + 449 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Fuse two linear layers together. After GeLU linearization, we observe an opportunity for further latency reduction. As shown in Figure 6, we fuse the linear layer before and after GeLU of a certain token, which reduces the communication associated with the MLP. Denote the input of a MLP block of $i$ -th layer as $X^{(i)} \\in \\mathbb{R}^{B \\times H \\times W \\times C}$ , the linear layers as $\\mathcal{W}_1^{(i)} \\in \\mathbb{R}^{C \\times K}$ and $\\mathcal{W}_2^{(i)} \\in \\mathbb{R}^{K \\times C}$ , the output of MLP as $X^{(i+1)} \\in \\mathbb{R}^{B \\times H \\times W \\times C}$ . The input dimension of GeLU is $B \\times H \\times W \\times K$ , and $C, K$ are channel numbers of linear layers. Note that we generally set the ratio of MLP (i.e., $\\frac{K}{C}$ ) to 2 or 4 in ViT models. The linearized MLP can be formulated as $X^{(i+1)} = (X^{(i)}\\mathcal{W}_1^{(i)})\\mathcal{W}_2^{(i)} = X^{(i)}(\\mathcal{W}_1^{(i)}\\mathcal{W}_2^{(i)})$ . In this way, $\\mathcal{W}_1^{(i)}\\mathcal{W}_2^{(i)}$ is fused into $\\mathcal{W}_f^{(i)} \\in \\mathbb{R}^{C \\times C}$ , which optimizes two high-dimensional MatMuls to only a single low-dimensional MatMul, further reducing the latency of MLP.", + "bbox": [ + 75, + 450, + 468, + 696 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Adding additional activations. After GeLU removal and linear fusion, there is no non-linearity in these tokens. To boost the accuracy, we additionally add a non-linear function after the fused linear positions. Here, we choose to add ReLU which incurs a cheaper cost than GeLU.", + "bbox": [ + 75, + 696, + 468, + 772 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 76, + 784, + 209, + 801 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.1. Experimental Setup", + "text_level": 1, + "bbox": [ + 76, + 809, + 266, + 825 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Experimental and MPC settings. In our experiments, we leverage the SecretFlow (SPU [39] V0.3.1b0)2 framework for private inference, which is popular for privacy-", + "bbox": [ + 76, + 832, + 468, + 878 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "preserving deep learning. We adopt the SEMI-2K [9] protocol, which is a semi-honest two-party computation protocol3. We follow Cheetah [22] and use the WAN mode for communication. Specifically, the communication bandwidth between the cloud instances is set to 44 MBps and the round-trip time is set to 40ms. Our experiments are evaluated on an Intel Xeon CPU@2.40 GHz with 62 GB RAM.", + "bbox": [ + 500, + 90, + 890, + 196 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Model architectures and datasets. Many researches have studied training ViTs on small datasets [12, 19, 23, 32, 35]. We consider two ViT architectures on three commonly used datasets following [19]. For the CIFAR-10/100 dataset, we set the ViT depth, # heads, hidden dimension, and patch size to 7, 4, 256, and 4, respectively. For TinyImageNet dataset, we set the ViT depth, # heads, hidden dimension, and patch size to 9, 12, 192, and 4, respectively.", + "bbox": [ + 498, + 196, + 892, + 316 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Searching settings. We run the NAS algorithm for 300 epochs with AdamW optimizer and a cosine learning rate across three datasets. We set $\\epsilon = 10^{-8}$ to avoid the zero denominator in RSAatt, and $\\lambda = 10^{-5}$ .", + "bbox": [ + 498, + 316, + 890, + 377 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Training settings. Following [19], we train the searched heterogeneous ViTs for 600 epochs on CIFAR-10/100 and 300 epochs on Tiny/ImageNet. We leverage data augmentations as [19]. For KD, we set the temperature $\\mathcal{T}$ to 1, and set $\\chi, \\beta, \\gamma$ to 1 as well. To explore the trade-off between inference accuracy and latency, we set $\\mu$ to $\\{0.1, 0.3, 0.5, 0.7\\}$ .", + "bbox": [ + 498, + 378, + 890, + 469 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.2. Comparison with Prior-Art Efficient Attentions", + "text_level": 1, + "bbox": [ + 500, + 477, + 890, + 493 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Baselines. We compare MPCViT with prior-art models on the inference accuracy and efficiency. We compare with MPCFormer [33], Linformer [58, 60], THE-X [6] and ViT variants in Table 2. Linformer is studied in [60] as an efficient Transformer variant for MPC and the compression rate of attention dimension is also defined as $\\mu$ . For networks compared with MPCViT, we only modify attention layer and keep MLP unchanged as the baseline ViT. For $\\mathrm{MPCViT^{+}}$ , we optimize attention and MLP simultaneously.", + "bbox": [ + 498, + 500, + 890, + 636 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Results and analysis. The main results are shown in Figure 7, where we report top-1 accuracy across three datasets and the network inference latency. The main findings are as follows:", + "bbox": [ + 498, + 637, + 890, + 696 + ], + "page_idx": 6 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1) MPCViT outperforms prior-art methods. Without KD, on Tiny-ImageNet, MPCViT with $\\mu = 0.1$ outperforms Linformer with $\\mu = 0.7$ by $0.57\\%$ better accuracy with $4.9\\times$ latency reduction; Compared with THE-X, MPCViT achieve $3.6\\%$ accuracy improvement with $1.9\\times$ latency reduction;", + "2) with proper KD, MPCViT even achieves $1.9\\%$ and $1.3\\%$ better accuracy with $6.2 \\times$ and $2.9 \\times$ latency reduction with $\\mu = 0.1$ and 0.3, compared with baseline ViT and MPCFormer on Tiny-ImageNet, respectively;" + ], + "bbox": [ + 509, + 705, + 890, + 867 + ], + "page_idx": 6 + }, + { + "type": "page_footnote", + "text": "3 Although the actual latency of each operator may be different for different MPC protocols, our proposed algorithm can be generally applied.", + "bbox": [ + 500, + 875, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_footnote", + "text": "2https://github.com/secretflow/secretflow", + "bbox": [ + 93, + 886, + 419, + 898 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "5058", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/f67c43023e97fa720a08debae52b104d9347a318e8d586b96fc1a95b85c7975d.jpg", + "image_caption": [ + "Figure 7. Top-1 Accuracy and inference latency comparison with baseline ViTs across three datasets." + ], + "image_footnote": [ + "- MPCViT w/o KD (ours) - MPCViT w/ KD (ours) Linformer - ReLU Softmax ViT - ScaleAttn ViT - THE-X" + ], + "bbox": [ + 101, + 89, + 356, + 252 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/b40f7df352253d606c6384dc36b32dcbf74e255e9b8ee633040552c1d93a1948.jpg", + "image_caption": [], + "image_footnote": [ + "Softmax-ScaleAttn ViT Softmax ViT MPCViT w/ Per-layer Search MPCFormer w/KD MPFCorner w/o KD" + ], + "bbox": [ + 357, + 90, + 612, + 251 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/f88ff4d0affc061ab1047c92c2fb697346fc1857b428795201ce1bbbd2d40afa.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 614, + 90, + 870, + 251 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/b4c2300e2cf1e73818bfec01f0fed8f8961791a2ceed4369c4c5720e689ea02c.jpg", + "image_caption": [ + "Figure 8. Latency and communication cost comparison of different layers in the 9-layer 12-head ViT with $\\mu = 0.5$ ." + ], + "image_footnote": [], + "bbox": [ + 78, + 323, + 468, + 443 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "3) we mix Softmax attention and ScaleAttn. Although it has a slightly higher accuracy in plaintext inference, it incurs at least $1.4 \\times$ and $1.2 \\times$ latency on CIFAR-10/100 and Tiny/ImageNet compared with MPCViT.", + "bbox": [ + 86, + 483, + 468, + 544 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We visualize the latency and communication cost comparison of Softmax ViT, ReLU Softmax ViT, and MPCViT in Figure 8. We can observe the latency changes proportionally with the communication. Also, we observe for MPCViT, RSAattn in middle layers (e.g., layer 2 to layer 5) tend to be preserved while RSAattn in early and final layers are likely to be replaced with ScaleAttn.", + "bbox": [ + 75, + 551, + 468, + 657 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.3. Comparison on Structure Granularities", + "text_level": 1, + "bbox": [ + 76, + 664, + 416, + 680 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "The choice of search space is important for MPCViT, so we compare different structure granularities of search space proposed in §4.2. We use the CIFAR-10 dataset for the comparison. As shown in Table 3, the head-wise search space achieves the best accuracy. We hypothesize although rowwise structure leads to the largest search space, such a fine-grained search space may introduce difficulties in NAS, and hence, leads to network architecture with inferior accuracy. Head-wise search space achieves the right balance between flexibility and optimizability.", + "bbox": [ + 75, + 686, + 468, + 839 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4. Ablation Study of MPCViT", + "text_level": 1, + "bbox": [ + 76, + 847, + 323, + 862 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Contribution of KD. One of our key techniques for training heterogeneous ViT is KD. We enumerate different", + "bbox": [ + 76, + 869, + 468, + 900 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/a2573a07ed3aea120e2554a1615fabbad238d434442e06028a9d20cdadeda0d5.jpg", + "table_caption": [ + "Table 3. Top-1 accuracy (%) comparison with different structure granularities of attention search space with different $\\mu$ ." + ], + "table_footnote": [], + "table_body": "
GranularityLayer-wiseRow-wiseHead-wise
μ = 0.593.0193.1693.21
μ = 0.793.3293.1393.38
", + "bbox": [ + 550, + 349, + 844, + 398 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/9a08e4441199f55b3738a89daa53ab570f7de6794928e36b3fc1ae53bb8fddca.jpg", + "table_caption": [ + "Table 4. Top-1 Accuracy $(\\%)$ comparison of different combinations of training loss function with $\\mu = 0.7$" + ], + "table_footnote": [], + "table_body": "
CELogits-based KDFeature-based KDCIFAR-10Tiny-ImageNet
✓93.3859.02
✓✓94.1862.39
✓✓94.1262.26
✓✓94.1461.80
✓✓✓94.2763.03
", + "bbox": [ + 524, + 440, + 864, + 506 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "combinations of KD and the results are shown in Table 4. We find that: 1) both logits-based and feature-based KD significantly improve the performance of ViT compared to using cross-entropy loss only; and 2) combining the two KD losses further improves the accuracy, especially on a larger dataset. The above findings indicate the importance of KD and the indispensability of three parts of $\\mathcal{L}_{train}$ .", + "bbox": [ + 496, + 534, + 890, + 640 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Consistency and scalability of NAS algorithm. We hope our NAS algorithm to be robust against hyperparameter choices and datasets. To analyze this consistency of our algorithm, we adjust the coefficient $\\lambda$ to three different values, i.e., $10^{-3}, 10^{-4}, 10^{-5}$ , and train a 7-layer ViT with 4 heads. We visualize the distribution of the architecture parameter $\\alpha$ in Figure 9, and we find that $\\alpha$ in each layer has a quite similar trend under different $\\lambda$ 's. Furthermore, when we change the number of heads to 8, or even train the same architecture on different datasets like CIFAR-100 and ImageNet, the distribution still shows a similar trend, empirically proving the consistency and scalability of our proposed NAS algorithm. Appendix F shows more distribution trends under other settings.", + "bbox": [ + 496, + 642, + 892, + 852 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Comparison with per-layer search. We also compare MPCViT with per-layer search which replaces RSA ttn heads in each layer uniformly given a certain $\\mu$ across three", + "bbox": [ + 498, + 854, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "5059", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/41d509e09a40f9937343b174f4d3340846d1bdcb18c6435f4f1a0030c24e1bfa.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 80, + 90, + 472, + 215 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/2ebc105be725a058dedd504b816301009ae3ab96525dc380b8d56cb549902ec7.jpg", + "image_caption": [ + "Figure 9. The distribution of architecture parameter $\\alpha$ for each head under different $\\lambda$ and different # heads on different datasets. We draw the average $\\alpha$ in each layer to show the similar trend." + ], + "image_footnote": [], + "bbox": [ + 80, + 215, + 468, + 339 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "datasets. As shown in Figure 7, MPCViT achieves a better Pareto front for accuracy and efficiency compared to the per-layer NAS. The results demonstrate the importance to search and replace RSAtn heads across different layers.", + "bbox": [ + 75, + 407, + 468, + 468 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5.5. MPCViT+ Evaluation", + "text_level": 1, + "bbox": [ + 76, + 477, + 282, + 491 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "As shown in Figure 7, when $\\mu$ decreases to 0.1, the major latency bottleneck comes from GeLU in MLP. We evaluate MPCViT+ for GeLU reduction on CIFAR-10/100 datasets with KD, which correspond to the ViT models with significant GeLU latency. We take token-wise optimization as an example (exploration for other granularity, i.e., layer-wise is shown in Appendix E), and control the GeLU linearization rate using a threshold $\\sigma$ such that $\\beta \\leftarrow 0(\\beta \\leq \\sigma)$ while $\\beta \\leftarrow 1(\\beta >\\sigma)$ . As shown in Figure 10, GeLU linearization leads to a little accuracy degradation, indicating that GeLU plays an important role in ViTs. MPCViT+ further reduces the latency on the basis of attention optimization, which proves the effectiveness of MPCViT+.", + "bbox": [ + 75, + 500, + 468, + 696 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Ablation study of additional ReLU. To analyze the help of adding additional ReLU after the fused linear layer, we fix $\\sigma = 0.75$ and perform the ablation study for MPCViT $^{+}$ under different latency constraints on CIFAR-10 dataset in Table 5. The results show that additional ReLU improves the representation ability of MPCViT $^{+}$ .", + "bbox": [ + 75, + 696, + 468, + 787 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/44c33377852467c5f9a7ebfa80997670a2f601f881c76a7ab21204de79b6aee2.jpg", + "table_caption": [ + "Table 5. Ablation study of adding additional ReLU after the fused linear layer under different latency constraints." + ], + "table_footnote": [], + "table_body": "
μ0.30.7
Accuracy (%)Latency (s)Accuracy (%)Latency (s)
MPCViT+93.9243.8894.2754.56
w/o ReLU93.7241.3793.8152.11
", + "bbox": [ + 99, + 824, + 450, + 883 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/962443157ace73d90e6a5aa7a29b14025b7483af36a183b369b32fa47cfdbc26.jpg", + "image_caption": [ + "Figure 10. Comparison between MPCViT and MPCViT+." + ], + "image_footnote": [], + "bbox": [ + 504, + 90, + 694, + 210 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/335b881b5710163e9ea935136e4978b341b135ca3f1926a835d686f4b634e513.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 696, + 90, + 888, + 210 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 253, + 617, + 270 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this paper, we present an MPC-friendly ViT family, dubbed MPCViT, to enable accurate yet efficient ViT inference in MPC. We propose a heterogeneous attention optimization space, and design an MPC-aware differentiable NAS algorithm to explore the search space. To further boost the inference efficiency, we propose $\\mathrm{MPCViT^{+}}$ to jointly optimize attention and MLP. Extensive experiments demonstrate that MPCViT consistently outperforms prior-art ViT architectures with both lower latency and higher accuracy. Our method can be further applied to large language models (LLMs) including BERT and GPT.", + "bbox": [ + 496, + 281, + 890, + 446 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement", + "text_level": 1, + "bbox": [ + 500, + 463, + 658, + 479 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work is supported in part by the NSFC (62125401) and the 111 Project (B18001).", + "bbox": [ + 500, + 489, + 890, + 518 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 500, + 535, + 596, + 550 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Saba Akram and Quarrat Ul Ann. Newton raphson method. International Journal of Scientific & Engineering Research, 6(7):1748-1752, 2015. 13", + "[2] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In Proceedings of the IEEE/CVF international conference on computer vision, pages 6836-6846, 2021. 1", + "[3] Gilad Asharov, Yehuda Lindell, Thomas Schneider, and Michael Zohner. More efficient oblivious transfer and extensions for faster secure computation. In ACM SIGSAC conference on Computer & Communications Security (CCS), pages 535-548, 2013. 14", + "[4] Daniel Bolya, Cheng-Yang Fu, Xiaoliang Dai, Peizhao Zhang, and Judy Hoffman. Hydra attention: Efficient attention with many heads. In European Conference on Computer Vision, pages 35-49. Springer, 2022. 2", + "[5] Jason Ross Brown, Yiren Zhao, Ilia Shumailov, and Robert D Mullins. Dartformer: Finding the best type of attention. arXiv preprint arXiv:2210.00641, 2022. 2, 5", + "[6] Tianyu Chen, Hangbo Bao, Shaohan Huang, Li Dong, Binxing Jiao, Daxin Jiang, Haoyi Zhou, Jianxin Li, and Furu Wei. THE-X: Privacy-preserving transformer inference with homomorphic encryption. In Findings of the Association for Computational Linguistics: ACL 2022, pages 3510-3520," + ], + "bbox": [ + 506, + 560, + 893, + 901 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "5060", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Dublin, Ireland, May 2022. Association for Computational Linguistics. 2, 3, 7", + "[7] Minsu Cho, Zahra Ghodsi, Brandon Reagen, Siddharth Garg, and Chinmay Hegde. Sphynx: Relu-efficient network design for private inference. arXiv preprint arXiv:2106.11755, 2021. 3", + "[8] Minsu Cho, Ameya Joshi, Brandon Reagen, Siddharth Garg, and Chinmay Hegde. Selective network linearization for efficient private inference. In International Conference on Machine Learning, pages 3947-3961. PMLR, 2022. 3, 15", + "[9] Ronald Cramer, Ivan Damgård, Daniel Escudero, Peter Scholl, and Chaoping Xing. SpdZ2k: Efficient mpc mod 2k for dishonest majority. In Annual International Cryptology Conference. Springer, pages 769-798, 2018. 4, 7, 13", + "[10] Xiaoliang Dai, Peizhao Zhang, Bichen Wu, Hongxu Yin, Fei Sun, Yanghan Wang, Marat Dukhan, Yunqing Hu, Yiming Wu, Yangqing Jia, et al. Chamnet: Towards efficient network design through platform-aware model adaptation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11398-11407, 2019. 5", + "[11] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In 9th International Conference on Learning Representations, ICLR 2021, Virtual Event, Austria, May 3-7, 2021. OpenReview.net, 2021. 1, 2, 4, 13", + "[12] Hanan Gani, Muzammal Naseer, and Mohammad Yaqub. How to train vision transformer on small-scale datasets? arXiv preprint arXiv:2210.07240, 2022. 7", + "[13] Zahra Ghodsi, Akshaj Kumar Veldanda, Brandon Reagen, and Siddharth Garg. Cryptonas: Private inference on a relu budget. Advances in Neural Information Processing Systems, 33:16961-16971, 2020. 3", + "[14] Oded Goldreich. Secure multi-party computation. 1998. 1, 3", + "[15] Chengyue Gong, Dilin Wang, Meng Li, Xinlei Chen, Zhicheng Yan, Yuandong Tian, Vikas Chandra, et al. Nasvit: Neural architecture search for efficient vision transformers with gradient conflict aware supernet training. In International Conference on Learning Representations, 2021. 1", + "[16] Jiaqi Gu, Hyoukjun Kwon, Dilin Wang, Wei Ye, Meng Li, Yu-Hsin Chen, Liangzhen Lai, Vikas Chandra, and David Z Pan. Multi-scale high-resolution vision transformer for semantic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12094-12103, 2022. 1", + "[17] Minghao Guo, Zhao Zhong, Wei Wu, Dahua Lin, and Junjie Yan. Irlas: Inverse reinforcement learning for architecture search. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9021-9029, 2019. 5", + "[18] Meng Hao, Hongwei Li, Hanxiao Chen, Pengzhi Xing, Guowen Xu, and Tianwei Zhang. Iron: Private inference on transformers. Advances in neural information processing systems, 2022. 3", + "[19] Ali Hassani, Steven Walton, Nikhil Shah, Abulikemu Abuduweili, Jiachen Li, and Humphrey Shi. Escaping the" + ], + "bbox": [ + 78, + 90, + 468, + 892 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "big data paradigm with compact transformers. arXiv preprint arXiv:2104.05704, 2021. 7", + "[20] Dan Hendrycks and Kevin Gimpel. Gaussian error linear units (gelus). arXiv preprint arXiv:1606.08415, 2016. 13", + "[21] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, et al. Distilling the knowledge in a neural network. arXiv preprint arXiv:1503.02531, 2(7), 2015. 6", + "[22] Zhicong Huang, Wen jie Lu, Cheng Hong, and Jiansheng Ding. Cheetah: Lean and fast secure Two-Party deep neural network inference. In USENIX Security Symposium (USENIX Security), pages 809–826, Boston, MA, Aug. 2022. 4, 7, 13", + "[23] Ethan Huynh. Vision transformers in 2022: An update on tiny imagenet. arXiv preprint arXiv:2205.10660, 2022. 7", + "[24] Yesmina JAAFra, Jean Luc Laurent, Aline Deruyver, and Mohamed Saber Naceur. Reinforcement learning for neural architecture search: A review. Image and Vision Computing, 89:57-66, 2019. 5", + "[25] Nandan Kumar Jha, Zahra Ghodsi, Siddharth Garg, and Brandon Reagen. Deepreduce: Relu reduction for fast private inference. In International Conference on Machine Learning, pages 4839-4849. PMLR, 2021. 3", + "[26] Nandan Kumar Jha and Brandon Reagen. Deepreshape: Redesigning neural networks for efficient private inference. arXiv preprint arXiv:2304.10593, 2023. 3", + "[27] Weiwen Jiang, Lei Yang, Edwin Hsing-Mean Sha, Qingfeng Zhuge, Shouzhen Gu, Sakyasingha Dasgupta, Yiyu Shi, and Jingtong Hu. Hardware/software co-exploration of neural architectures. IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 39(12):4805-4815, 2020. 5", + "[28] Jacob Devlin Ming-Wei Chang Kenton and Lee Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of naacL-HLT, volume 1, page 2, 2019. 2", + "[29] Nikita Kitaev, Lukasz Kaiser, and Anselm Levskaya. Reformer: The efficient transformer. In 8th International Conference on Learning Representations, ICLR 2020, Addis Ababa, Ethiopia, April 26-30, 2020. OpenReview.net, 2020. 2", + "[30] Brian Knott, Shobha Venkataraman, Awni Hannun, Shubho Sengupta, Mark Ibrahim, and Laurens van der Maaten. Crypten: Secure multi-party computation meets machine learning. Advances in Neural Information Processing Systems, 34:4961-4973, 2021. 13", + "[31] Souvik Kundu, Shunlin Lu, Yuke Zhang, Jacqueline Tiffany Liu, and Peter A. Beerel. Learning to linearize deep neural networks for secure and efficient private inference. In The Eleventh International Conference on Learning Representations, ICLR 2023, Kigali, Rwanda, May 1-5, 2023. OpenReview.net, 2023. 3", + "[32] Seunghoon Lee, Seunghyun Lee, and Byung Cheol Song. Improving vision transformers to learn small-size dataset from scratch. IEEE Access, 10:123212-123224, 2022. 7", + "[33] Dacheng Li, Hongyi Wang, Rulin Shao, Han Guo, Eric P. Xing, and Hao Zhang. MPCFORMER: fast, performant and provate transformer inference with MPC. In The Eleventh International Conference on Learning Representations, ICLR 2023, Kigali, Rwanda, May 1-5, 2023. OpenReview.net," + ], + "bbox": [ + 501, + 92, + 890, + 892 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "5061", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "2023. 2, 3, 4, 7, 14", + "[34] Zhexin Li, Tong Yang, Peisong Wang, and Jian Cheng. Q-vit: Fully differentiable quantization for vision transformer. arXiv preprint arXiv:2201.07703, 2022. 5", + "[35] Yahui Liu, Enver Sangineto, Wei Bi, Nicu Sebe, Bruno Lepri, and Marco Nadai. Efficient training of visual transformers with small datasets. Advances in Neural Information Processing Systems, 34:23818-23830, 2021. 7", + "[36] Zexiang Liu, Dong Li, Kaiyue Lu, Zhen Qin, Weixuan Sun, Jiacheng Xu, and Yiran Zhong. Neural architecture search on efficient transformers and beyond. arXiv preprint arXiv:2207.13955, 2022. 5", + "[37] Qian Lou, Yilin Shen, Hongxia Jin, and Lei Jiang. Safenet: A secure, accurate and fast neural network inference. In International Conference on Learning Representations, 2020. 3", + "[38] Jiachen Lu, Jinghan Yao, Junge Zhang, Xiatian Zhu, Hang Xu, Weiguo Gao, Chunjing Xu, Tao Xiang, and Li Zhang. Soft: Softmax-free transformer with linear complexity. Advances in Neural Information Processing Systems, 34:21297-21309, 2021. 2", + "[39] Junming Ma, Yancheng Zheng, Jun Feng, Derun Zhao, Haoqi Wu, Wenjing Fang, Jin Tan, Chaofan Yu, Benyu Zhang, and Lei Wang. SecretFlow-SPU: A performant and User-Friendly framework for Privacy-Preserving machine learning. In 2023 USENIX Annual Technical Conference (USENIX ATC 23), pages 17–33, Boston, MA, July 2023. USENIX Association. 7", + "[40] Andre Martins and Ramon Astudillo. From softmax to sparsemax: A sparse model of attention and multi-label classification. In International conference on machine learning, pages 1614-1623. PMLR, 2016. 4, 14", + "[41] Paul Michel, Omer Levy, and Graham Neubig. Are sixteen heads really better than one? Advances in neural information processing systems, 32, 2019. 5, 15", + "[42] Pratyush Mishra, Ryan Lehmkuhl, Akshayaram Srinivasan, Wenting Zheng, and Raluca Ada Popa. Delphi: A cryptographic inference service for neural networks. In USENIX Security Symposium, pages 2505-2522, 2020. 1, 3", + "[43] Payman Mohassel and Peter Rindal. Aby3: A mixed protocol framework for machine learning. In Proceedings of the 2018 ACM SIGSAC conference on computer and communications security, pages 35-52, 2018. 3", + "[44] Payman Mohassel and Yupeng Zhang. Securel: A system for scalable privacy-preserving machine learning. In IEEE symposium on security and privacy (S&P), pages 19-38. IEEE, 2017. 3, 4", + "[45] Moni Naor and Benny Pinkas. Computationally secure oblivious transfer. Journal of Cryptology, 18(1):1-35, 2005. 14", + "[46] Zizheng Pan, Bohan Zhuang, Haoyu He, Jing Liu, and Jianfei Cai. Less is more: Pay less attention in vision transformers. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 2035-2043, 2022. 5", + "[47] Hongwu Peng, Shanglin Zhou, Yukui Luo, Shijin Duan, Nuo Xu, Ran Ran, Shaoyi Huang, Chenghong Wang, Tong Geng, Ang Li, et al. Polympcnet: Towards relu-free neural architecture search in two-party computation based private inference. arXiv preprint arXiv:2209.09424, 2022. 3" + ], + "bbox": [ + 78, + 90, + 468, + 891 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[48] Hongwu Peng, Shanglin Zhou, Yukui Luo, Nuo Xu, Shijin Duan, Ran Ran, Jiahui Zhao, Shaoyi Huang, Xi Xie, Chenghong Wang, et al. Rrnet: Towards relu-reduced neural network for two-party computation based private inference. arXiv preprint arXiv:2302.02292, 2023. 3", + "[49] Zhen Qin, Weixuan Sun, Hui Deng, Dongxu Li, Yunshen Wei, Baohong Lv, Junjie Yan, Lingpeng Kong, and Yiran Zhong. cosformer: Rethinking softmax in attention. In The Tenth International Conference on Learning Representations, ICLR 2022, Virtual Event, April 25-29, 2022. OpenReview.net, 2022. 2", + "[50] Deevashwer Rathee, Mayank Rathee, Rahul Kranti Kiran Goli, Divya Gupta, Rahul Sharma, Nishanth Chandran, and Aseem Rastogi. Sirnn: A math library for secure rn n inference. In 2021 IEEE Symposium on Security and Privacy (SP), pages 1003-1020. IEEE, 2021. 14", + "[51] Deevashwer Rathee, Mayank Rathee, Nishant Kumar, Nishanth Chandran, Divya Gupta, Aseem Rastogi, and Rahul Sharma. Cryptflow2: Practical 2-party secure inference. In ACM SIGSAC Conference on Computer and Communications Security (CCS), pages 325-342, 2020. 1", + "[52] Adi Shamir. How to share a secret. Communications of the ACM, 22(11):612-613, 1979. 13", + "[53] Jeong-geun Song. Ufo-vit: High performance linear vision transformer without softmax. arXiv preprint arXiv:2109.14382, 2021. 2, 4, 14", + "[54] Xiu Su, Shan You, Jiyang Xie, Mingkai Zheng, Fei Wang, Chen Qian, Changshui Zhang, Xiaogang Wang, and Chang Xu. Vitas: Vision transformer architecture search. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXI, pages 139-157. Springer, 2022. 5", + "[55] Mingxing Tan, Bo Chen, Ruoming Pang, Vijay Vasudevan, Mark Sandler, Andrew Howard, and Quoc V Le. Mnasnet: Platform-aware neural architecture search for mobile. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2820-2828, 2019. 5", + "[56] Elena Voita, David Talbot, Fedor Moiseev, Rico Sennrich, and Ivan Titov. Analyzing multi-head self-attention: Specialized heads do the heavy lifting, the rest can be pruned. In Anna Korhonen, David R. Traum, and Lluis Marquez, editors, Proceedings of the 57th Conference of the Association for Computational Linguistics, ACL 2019, Florence, Italy, July 28- August 2, 2019, Volume 1: Long Papers, pages 5797-5808. Association for Computational Linguistics, 2019. 5, 15", + "[57] Kuan Wang, Zhijian Liu, Yujun Lin, Ji Lin, and Song Han. Haq: Hardware-aware automated quantization with mixed precision. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 8612-8620, 2019. 5", + "[58] Sinong Wang, Belinda Z Li, Madian Khabsa, Han Fang, and Hao Ma. Linformer: Self-attention with linear complexity. arXiv preprint arXiv:2006.04768, 2020. 2, 4, 7, 14", + "[59] Xiaolong Wang, Ross Girshick, Abhinav Gupta, and Kaiming He. Non-local neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 7794-7803, 2018. 3, 4", + "[60] Yongqin Wang, G Edward Suh, Wenjie Xiong, Benjamin" + ], + "bbox": [ + 501, + 92, + 890, + 893 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "5062", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Lefaudeau, Brian Knott, Murali Annavaram, and Hsien-Hsin S Lee. Characterization of mpc-based private inference for transformer-based models. In 2022 IEEE International Symposium on Performance Analysis of Systems and Software (ISPASS), pages 187-197. IEEE, 2022. 1, 7, 13, 14", + "[61] Bichen Wu, Xiaoliang Dai, Peizhao Zhang, Yanghan Wang, Fei Sun, Yiming Wu, Yuandong Tian, Peter Vajda, Yangqing Jia, and Kurt Keutzer. Fbnet: Hardware-aware efficient convnet design via differentiable neural architecture search. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10734-10742, 2019. 5", + "[62] Mengzhou Xia, Zexuan Zhong, and Danqi Chen. Structured pruning learns compact and accurate models. In Smaranda Muresan, Preslav Nakov, and Aline Villavicencio, editors, Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), ACL 2022, Dublin, Ireland, May 22-27, 2022, pages 1513-1528. Association for Computational Linguistics, 2022. 15", + "[63] Andrew C Yao. Protocols for secure computations. In 23rd annual symposium on foundations of computer science (sfcs 1982), pages 160-164. IEEE, 1982. 14", + "[64] Pengchuan Zhang, Xiyang Dai, Jianwei Yang, Bin Xiao, Lu Yuan, Lei Zhang, and Jianfeng Gao. Multi-scale vision longformer: A new vision transformer for high-resolution image encoding. In Proceedings of the IEEE/CVF international conference on computer vision, pages 2998-3008, 2021. 1" + ], + "bbox": [ + 78, + 90, + 470, + 446 + ], + "page_idx": 11 + }, + { + "type": "page_number", + "text": "5063", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 11 + } +] \ No newline at end of file diff --git a/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/844d9362-4725-44da-8709-8687e3c64eb2_model.json b/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/844d9362-4725-44da-8709-8687e3c64eb2_model.json new file mode 100644 index 0000000000000000000000000000000000000000..3ba9c53010f1359129b53823d51589f9228eb74d --- /dev/null +++ b/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/844d9362-4725-44da-8709-8687e3c64eb2_model.json @@ -0,0 +1,2743 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.172, + 0.13, + 0.8, + 0.177 + ], + "angle": 0, + "content": "MPCViT: Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention" + }, + { + "type": "text", + "bbox": [ + 0.186, + 0.202, + 0.78, + 0.258 + ], + "angle": 0, + "content": "Wenxuan Zeng\\(^{1}\\) Meng Li\\(^{1*}\\) Wenjie Xiong\\(^{2}\\) Tong Tong\\(^{1}\\) Wen-jie Lu\\(^{3}\\) Jin Tan\\(^{3}\\) Runsheng Wang\\(^{1}\\) Ru Huang\\(^{1}\\) \n\\(^{1}\\)Peking University \\(^{2}\\)Virginia Tech \\(^{3}\\)Ant Group" + }, + { + "type": "text", + "bbox": [ + 0.182, + 0.26, + 0.786, + 0.294 + ], + "angle": 0, + "content": "{zwx.andy,tongtong}@stu.pku.edu.cn, {meng.li,wrs,ruhuang}@pku.edu.cn, wenjiex@vt.edu, {juhou.lwj,tanjin.tj}@antgroup.com" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.327, + 0.314, + 0.344 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.359, + 0.474, + 0.768 + ], + "angle": 0, + "content": "Secure multi-party computation (MPC) enables computation directly on encrypted data and protects both data and model privacy in deep learning inference. However, existing neural network architectures, including Vision Transformers (ViTs), are not designed or optimized for MPC and incur significant latency overhead. We observe Softmax accounts for the major latency bottleneck due to a high communication complexity, but can be selectively replaced or linearized without compromising the model accuracy. Hence, in this paper, we propose an MPC-friendly ViT, dubbed MPCViT, to enable accurate yet efficient ViT inference in MPC. Based on a systematic latency and accuracy evaluation of the Softmax attention and other attention variants, we propose a heterogeneous attention optimization space. We also develop a simple yet effective MPC-aware neural architecture search algorithm for fast Pareto optimization. To further boost the inference efficiency, we propose MPCViT\\(^+\\), to jointly optimize the Softmax attention and other network components, including GeLU, matrix multiplication, etc. With extensive experiments, we demonstrate that MPCViT achieves \\(1.9\\%\\), \\(1.3\\%\\) and \\(3.6\\%\\) higher accuracy with \\(6.2\\times\\), \\(2.9\\times\\) and \\(1.9\\times\\) latency reduction compared with baseline ViT, MPCFormer and THE-X on the Tiny-ImageNet dataset, respectively. MPCViT\\(^+\\) further achieves a better Pareto front compared with MPCViT. The code and models for evaluation are available at https://github.com/PKU-SEC-Lab/mpcvit." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.794, + 0.21, + 0.81 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.819, + 0.471, + 0.882 + ], + "angle": 0, + "content": "As machine learning models are handling increasingly sensitive data and tasks, privacy has become one of the major concerns during the model deployment. Secure multi-party computation (MPC) [14] can protect the privacy of" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.327, + 0.639, + 0.435 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.64, + 0.327, + 0.774, + 0.435 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.774, + 0.327, + 0.892, + 0.435 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.439, + 0.894, + 0.482 + ], + "angle": 0, + "content": "Figure 1. The latency breakdown of a Transformer block w.r.t (a) # heads and (b) # tokens; and (c) the relative error of Softmax and ReLU Softmax with different input variances." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.507, + 0.892, + 0.537 + ], + "angle": 0, + "content": "both data and deep neural network (DNN) models and has gained a lot of attention in recent years [42, 51, 60]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.538, + 0.893, + 0.884 + ], + "angle": 0, + "content": "However, existing DNN architectures, especially the recently proposed Vision Transformers (ViTs) [2, 11, 64], are not designed or optimized for MPC (the high-level private ViT inference framework in MPC is shown in Figure 2 and Appendix A.1). Although ViTs have achieved superior performance for various vision tasks [2, 15, 16, 64], they face several realistic limitations when directly deployed in MPC: 1) communication overhead: in contrast to regular inference on plaintext, operations like Softmax, GeLU, max, etc, require intensive communication in MPC, which usually dominates the total inference latency [42, 60]. For example, Softmax is usually very lightweight in plaintext inference. However, as shown in Figure 1(a) and Figure 1(b), it accounts for the majority of the Transformer inference latency due to the high communication complexity; 2) approximation error: operations like exponential, tanh, reciprocal, etc, cannot be computed directly and require iterative approximation, limiting the computation accuracy. For instance, as shown in Figure 1(c), the relative error of Softmax significantly increases when the input variance is large due to its narrow dynamic range [60]. In contrast, replacing exponential in Softmax with ReLU reduces the relative error drastically (denoted as ReLU Softmax in §2.2)." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.886, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Numerous efficient Transformer variants have been pro" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.888, + 0.222, + 0.9 + ], + "angle": 0, + "content": "*Corresponding author." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5052" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.123, + 0.092, + 0.852, + 0.226 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.197, + 0.227, + 0.768, + 0.241 + ], + "angle": 0, + "content": "Figure 2. An overall illustration of private Vision Transformer inference in the MPC framework." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.266, + 0.473, + 0.538 + ], + "angle": 0, + "content": "posed in recent years [5, 29, 49, 58]. Linear Transformers, including Linformer [58], cosFormer [49], Reformer [29], etc, reduce the quadratic computation complexity of the attentions and significantly accelerate model inference for long sequences. However, these Transformer optimizations have primarily focused on reducing the network computation. Hence, they either retain complex non-linear functions or still require iterative approximation, both resulting in intensive communication overhead in MPC. Recently, MPC-Former [33] and THE-X [6] are proposed to improve the inference efficiency of BERT [28] in MPC. MPCFormer simplifies Softmax by replacing exponential with a more MPC-friendly quadratic operation while THE-X approximates Softmax with a small estimation network. However, their attention variants is not flexible and can still be too expensive for certain latency constraints. Moreover, the network-level optimization suffers from a large accuracy degradation when directly applied to vision tasks." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.54, + 0.47, + 0.751 + ], + "angle": 0, + "content": "In this work, we first breakdown Softmax into more atomic operations and analyze their impact on the inference accuracy and efficiency, based on which we propose and compare a set of attention variants comprehensively. The comparison enables us to find MPC-friendly attention variants, which are either highly accurate or highly efficient. We further observe not all attentions are equally important within a ViT. Based on these observations, we propose the first MPC-friendly ViT architecture, dubbed MPCViT. MPCViT features a heterogeneous attention design space to explore the trade-off between accuracy and efficiency, and an MPC-aware differentiable neural architecture search (NAS) algorithm for effective Pareto optimization. Our contributions can be summarized as follows:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.764, + 0.47, + 0.826 + ], + "angle": 0, + "content": "- We breakdown Softmax and reveal the impact of atomic operations on the inference accuracy and efficiency, based on which a heterogeneous attention design space is proposed." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.84, + 0.471, + 0.902 + ], + "angle": 0, + "content": "- We propose an effective MPC-aware differentiable NAS algorithm to explore the attention design space based on real latency measurements instead of proxies. To the best of our knowledge, we make the first" + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.764, + 0.471, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.531, + 0.266, + 0.892, + 0.296 + ], + "angle": 0, + "content": "attempt to introduce the MPC-aware NAS to optimize ViT inference in MPC." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.306, + 0.892, + 0.398 + ], + "angle": 0, + "content": "- Our MPC-friendly ViT model family, MPCViT, outperforms prior-art models in MPC in terms of both accuracy and efficiency. MPCViT achieves \\(1.9\\%\\) and \\(1.3\\%\\) higher accuracy with \\(6.2\\times\\) and \\(2.9\\times\\) latency reduction compared with baseline ViT and MPCFormer on Tiny-ImageNet dataset, respectively." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.407, + 0.892, + 0.468 + ], + "angle": 0, + "content": "- We further extend MPCViT to optimize other Transformer components simultaneously with Softmax, named \\(\\mathrm{MPCViT}^+\\), achieving an even better Pareto front compared with MPCViT." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.306, + 0.892, + 0.468 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.481, + 0.804, + 0.497 + ], + "angle": 0, + "content": "2. Preliminaries and Related Works" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.506, + 0.747, + 0.521 + ], + "angle": 0, + "content": "2.1. ViT and Efficient Attention" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.529, + 0.892, + 0.636 + ], + "angle": 0, + "content": "ViT architecture. ViT [11] has demonstrated a great potential to capture the long-range visual dependencies. It takes image patches as input and is composed of an input projection layer, a stack of Transformer layers, and a task-specific multi-layer perceptron (MLP) head. Each layer consists of a multi-head attention (MHA) layer and an MLP block. The core computation is the Softmax attention:" + }, + { + "type": "equation", + "bbox": [ + 0.55, + 0.645, + 0.842, + 0.681 + ], + "angle": 0, + "content": "\\[\n\\operatorname {A t t e n t i o n} (Q, K, V) = \\operatorname {S o f t m a x} \\left(\\frac {Q K ^ {T}}{\\sqrt {d _ {k}}}\\right) V,\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.689, + 0.892, + 0.75 + ], + "angle": 0, + "content": "where \\(Q, K, V\\) are queries, keys and values, respectively. \\(d_{k}\\) denotes the embedding dimension of each key, and Softmax normalizes the attention map. The detailed explanation of ViT architecture is shown in Figure 2 and Appendix A.2." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Linear attention. Linear attention has been widely studied in previous works [5, 29, 38, 49]. These works aim at reducing the quadratic increase of compute and memory by leveraging special kernel functions. Different kernel functions have been proposed in existing works [4, 49, 53, 58]. UFO-ViT [53] proposes to use \\(\\ell 2\\)-Norm as the kernel function while CosFormer [49] leverages the cosine distance kernel. Linformer [58] approximates self-attention by a low-rank matrix. Hydra Attention [4] proposes to use as many heads as possible to further reduce the computation" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5053" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.205, + 0.088, + 0.76, + 0.102 + ], + "angle": 0, + "content": "Table 1. Comparison among existing network optimizations for the efficient private inference." + }, + { + "type": "table", + "bbox": [ + 0.118, + 0.102, + 0.855, + 0.328 + ], + "angle": 0, + "content": "
MethodModelTechniqueOptimized ComponentGranularityLinear Fusion
Delphi [42]CNNReLU-aware NASReLULayerX
DeepReDuce [25]CNNManually removalReLULayerX
CryptoNAS [13]CNNReLU-aware NASReLULayerX
SNL [8]CNNReLU-aware NASReLUChannel, pixelX
Sphinx [7]CNNBlock-level NASReLUBlockX
SENet [31]CNNSensitivity-aware alloc.ReLULayer, pixelX
RRNet [48]CNNHardware-aware NASReLULayerX
DeepReShape [26]CNNReLU-equalizationReLUStageX
SAFENet [31]CNNMixed-precision poly. approx.ReLUChannelX
THE-X [6]BERTPolynomial approx.GeLU, Softmax, LayerNormNetworkX
MPCFormer [33]BERTPolynomial approx.Softmax, GeLUNetworkX
MPCViT (ours)ViTMPC-aware NASSoftmaxLayer, head, rowX
Heterogeneous attention
MPC-aware NAS
MPCViT+ (ours)ViTHeterogeneous attentionSoftmax, GeLU, MatMulLayer, head, row, token✓
GeLU linearization
Linear fusion
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.353, + 0.47, + 0.414 + ], + "angle": 0, + "content": "complexity of the linear attention. However, these works primarily focus on reducing the network computation rather than the communication overhead and are not beneficial for ViT inference in MPC." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.418, + 0.473, + 0.618 + ], + "angle": 0, + "content": "Non-local neural networks and Scaling attention. [59] presents a generic non-local operation to capture long-range dependencies. The formulation is defined as \\(\\frac{1}{\\mathcal{C}(x)}\\sum_{\\forall j}f(x_i,x_j)g(x_j)\\), where \\(x\\) denotes the input feature map and \\(f(\\cdot)\\) is a similarity function, e.g., cosine or Euclidean distance. \\(g(\\cdot)\\) computes a certain input representation, and \\(\\mathcal{C}(x)\\) is a normalization factor. By setting \\(f(\\cdot)\\) as the dot-product similarity and \\(\\mathcal{C}(x) = n\\), where \\(n\\) is the sequence length, we get an attention variant, named Scaling Attention (ScaleAttn). ScaleAttn is an extremely simple attention and only involves linear operations like multiplication and addition. ScaleAttn can be further reparameterized to accelerate computation1 as below:" + }, + { + "type": "equation", + "bbox": [ + 0.098, + 0.634, + 0.449, + 0.669 + ], + "angle": 0, + "content": "\\[\n\\mathrm {S c a l e A t t n} (Q, K, V) = \\frac {1}{n} (Q K ^ {T}) V = \\frac {Q}{\\sqrt {n}} (\\frac {K ^ {T}}{\\sqrt {n}} V).\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.688, + 0.312, + 0.706 + ], + "angle": 0, + "content": "2.2. Multi-Party Computation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.715, + 0.47, + 0.854 + ], + "angle": 0, + "content": "MPC [14] is a cryptographic technique that offers a promising solution to protect the privacy of both data and model during deep learning inference. Appendix B depicts the cryptographic primitives for MPC, including Secret Sharing, Oblivious Transfer and Garble Circuit. [14] proposes an efficient MPC protocol for addition and multiplication. [44] proposes efficient two-party computation protocols for various arithmetic operations and approximations for non-linear functions in DNN. For example, [44]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.354, + 0.821, + 0.37 + ], + "angle": 0, + "content": "approximates Softmax with ReLU Softmax, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.556, + 0.377, + 0.837, + 0.412 + ], + "angle": 0, + "content": "\\[\n\\operatorname {R e L U S o f t m a x} (x) = \\frac {\\operatorname {R e L U} (x _ {i})}{\\sum_ {i} \\operatorname {R e L U} (x _ {i}) + \\epsilon},\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.418, + 0.892, + 0.538 + ], + "angle": 0, + "content": "where \\(\\epsilon\\) is a very small value to avoid the zero denominator. ABY3 [43] is proposed to enable efficient conversion between different secret sharing schemes in three-party computation. Delphi [42] develops a hybrid MPC protocol and optimizes the network to explore the performance-accuracy trade-off. Iron [18] proposes a set of protocols to reduce the communication overhead of matrix-matrix multiplications (MatMuls), LayerNorm, etc for Transformer-based models." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.539, + 0.893, + 0.903 + ], + "angle": 0, + "content": "Although MPC protocols have been improved significantly in recent years, DNN inference in MPC still suffers from intensive communication and latency overhead compared to the plaintext inference. To reduce the latency, different algorithms have been proposed to optimize convolutional NNs (CNNs) with a focus on ReLU. We compare the important characteristics of our methods with existing related work in Table 1. SNL [8] and DeepReduce [25] propose to remove ReLUs and linearize a subset of neurons selectively. SAFENet [37], Delphi [42], RRNet [48] and PolyMPCNet [47] replace ReLUs with polynomial functions that are more MPC-friendly via NAS for CNNs. Sphynx [7] further develops an MPC-friendly architecture search space for CNNs and leverages NAS to optimize the accuracy given different latency constraints. However, these works mainly focus on the ReLU counts in CNNs, and accelerating ViTs with latency consideration is still a challenge. MPCFormer [33] and THE-X [6] recently propose to replace Softmax with more MPC-friendly operations for BERT, but the network-level method incurs limited latency reduction and a large accuracy degradation. As shown in Table 1, our work proposes an MPC-aware NAS to explore a fined-grained heterogeneous attention optimization space, and further presents a GeLU linearization" + }, + { + "type": "page_footnote", + "bbox": [ + 0.077, + 0.875, + 0.47, + 0.9 + ], + "angle": 0, + "content": "1In this work, we do not focus on computational overhead in MPC since communication dominates the overhead." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5054" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.088, + 0.892, + 0.114 + ], + "angle": 0, + "content": "Table 2. Top-1 accuracy and latency comparison of different attention variants on CIFAR-10. The rows in grey are attention variants with the lowest latency and the highest accuracy, respectively. We also show the properties and remaining operations of each variant." + }, + { + "type": "table", + "bbox": [ + 0.105, + 0.115, + 0.867, + 0.25 + ], + "angle": 0, + "content": "
Attention VariantMonotonicityNon-negativityNormalizationExponentialMaxReciprocalAcc. (%)Lat. (s)
Softmax Attention [11]✓✓✓✓✓✓92.696.82
Linformer Attention [58]✓✓✓✓✓✓90.855.44
ReLU Attention✓✓✗✗✓✗failfail
ReLU6 Attention✓✓✗✗✓✗90.503.02
Sparsemax Attention [40]✓✓✗✗✓✗91.233.23
XNorm Attention [53]✓✗✗✗✗✓91.2413.25
Square Attention✗✓✗✗✗✗91.270.72
2Quad Attention [33]✗✓✓✗✗✓91.864.22
Scaling Attention (ScaleAttn) [59]✓✗✗✗✗✗91.520.66
ReLU Softmax Attention (RSAAttn) [44]✓✓✓✗✓✓92.315.32
" + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.271, + 0.468, + 0.41 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.413, + 0.471, + 0.469 + ], + "angle": 0, + "content": "Figure 3. (a) Latency breakdown of a 4-head ViT with 256 hidden dimension and 65 tokens on CIFAR-10 dataset; (b) latency breakdown of Softmax. Both (a) and (b) consist of SEMI-2K (outside) and Cheetah (inside) protocols." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.495, + 0.343, + 0.51 + ], + "angle": 0, + "content": "technique to reduce the latency of MLP." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.526, + 0.396, + 0.544 + ], + "angle": 0, + "content": "3. Motivating Inspiration of MPCViT" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.553, + 0.47, + 0.629 + ], + "angle": 0, + "content": "In this section, we breakdown Softmax for accuracy and efficiency evaluation and compare two ways of building MPC-friendly ViTs. The analysis serves as our motivation of proposing MPCViT, which features heterogeneous attention and NAS-based Pareto optimization." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.63, + 0.471, + 0.901 + ], + "angle": 0, + "content": "Motivation 1: ViT latency bottleneck in MPC. In Figure 1, we profile the latency of a Transformer block with different number of heads and tokens. We now further dive into Softmax and evaluate its latency breakdown. We profile a 4-head ViT with 65 tokens and 256 hidden dimension assuming the WAN setting as defined in §5.1. We consider two widely used protocols, including SEMI-2K [9] and Cheetah [22]. From both Figure 1 and Figure 3, we make the following observations: 1) Softmax is the major latency bottleneck in most cases. The latency of GeLU and MatMuls also becomes non-negligible when the number of heads or tokens is small; 2) Softmax mainly involves three operations, including exponential, reciprocal and max. All of the operations are important for the latency overhead. Therefore, we are motivated to get rid of these expensive operations as many as possible, and we propose to first focus on optimizing the Softmax and only consider GeLU and MatMul when the number of heads or tokens is small." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.274, + 0.892, + 0.548 + ], + "angle": 0, + "content": "Motivation 2: comparison of different attention variants. To reduce the latency of Softmax in the attention module, there are two different ways, i.e., 1) reducing the dimension of \\( QK^T \\) such as Linformer [58], which approximates \\( QK^T \\) with a low rank matrix; and 2) simplifying Softmax by replacing exponential, reciprocal or max with other operations. For the second method, while the possible activation variants can be abundant, we observe the following three important properties of Softmax, which helps us to select promising candidates: monotonicity, non-negativity, and normalized sum to 1. The first two properties are related to the exponential while the last one is achieved with reciprocal. We propose and evaluate the following variants, including ReLU, ReLU6, Sparsemax [40], XNorm [53], Square, Scaling [59], 2Quard [33], Linformer [58] and ReLU Softmax [44]. We define the attention with ReLU Softmax as RSAttn for short. The formulation of these attention variants is described in Appendix C." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.553, + 0.893, + 0.903 + ], + "angle": 0, + "content": "To compare these attention variants, we train each model for 300 epochs on CIFAR-10 and compare the latency, accuracy, remaining operations, and how they satisfy the properties of Softmax in Table 2. We make the following observations: 1) Attention with more expensive operations can be more inefficient. For instance, 2Quad has an extra reciprocal compared with Square such that 2Quad suffers from a higher latency; 2) Linformer suffers from a high accuracy degradation (\\(\\sim 1.8\\%\\) compared with Softmax attention) as it significantly reduces the matrix dimensions such that the model learning capability is degraded, and the computation reduction of this optimization cannot benefit latency reduction a lot. Hence, the first method is not preferred; 3) ReLU Softmax and 2Quad achieve higher accuracy among other variants and we hypothesize this is because they both normalize the sum to 1, which is realized with reciprocal and also leads to relatively higher latency. ReLU Softmax is more preferred over Softmax and 2Quad due to its small approximation error and small accuracy degradation; 4) Scaling is equivalent to directly removing the Softmax. Although it is the fastest, directly linearizing all the Softmax leads to a large accuracy degradation; 5) it is interesting to notice that although XNorm attention has linear com" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5055" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.136 + ], + "angle": 0, + "content": "putation, it incurs the highest latency because computing \\(\\ell 2\\)-norm involves both reciprocal and square root, both of which are expensive in MPC." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.137, + 0.468, + 0.302 + ], + "angle": 0, + "content": "Motivation 3: Not all attentions are equally important. As observed in [5, 36, 41, 46, 54, 56], not all attentions are equally important and different layer prefers different attention type. For instance, [46] identifies the minor contribution of the early attention layers in recent ViTs, while [34] demonstrates the second head shows higher importance than other heads. Thus, the importance of attentions among different layers or even the attentions within the same layer can be different. It indicates we can safely replace the expensive Softmax or ReLU Softmax with the cheaper Scaling without compromising the network accuracy." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.303, + 0.468, + 0.334 + ], + "angle": 0, + "content": "Remark The analysis above provides us with the following intuitions when designing an MPC-friendly ViT:" + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.339, + 0.468, + 0.385 + ], + "angle": 0, + "content": "1) ReLU Softmax is more preferred over Softmax and more MPC-friendly, and Scaling has the highest inference efficiency;" + }, + { + "type": "text", + "bbox": [ + 0.088, + 0.392, + 0.468, + 0.437 + ], + "angle": 0, + "content": "2) by selectively replacing the ReLU Softmax with the cheaper Scaling, it is possible to reduce the inference latency without compromising the inference accuracy;" + }, + { + "type": "text", + "bbox": [ + 0.088, + 0.445, + 0.468, + 0.489 + ], + "angle": 0, + "content": "3) when the latency of GeLU and Softmax are comparable, we have an opportunity to further simplify GeLU along with Softmax." + }, + { + "type": "list", + "bbox": [ + 0.088, + 0.339, + 0.468, + 0.489 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.498, + 0.39, + 0.515 + ], + "angle": 0, + "content": "4. The Proposed MPCViT Algorithm" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.524, + 0.468, + 0.569 + ], + "angle": 0, + "content": "In this section, we introduce MPCViT, which for the first time optimizes the ViT architecture with NAS-based algorithm for a fast private inference in MPC." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.576, + 0.354, + 0.591 + ], + "angle": 0, + "content": "4.1. Overview of Optimization Flow" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.599, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Based on the motivations described above, we now describe our MPC-aware ViT optimization flow as shown in Figure 4. We propose to replace the Softmax with the accurate yet MPC-friendly ReLU Softmax in the ViT first and then, linearize the relatively \"unimportant\" ReLU Softmax with efficient Scaling. To find the \"unimportant\" ReLU Softmax, we first design a heterogeneous search space that includes both ReLU Softmax and Scaling attentions. Architecture parameters are defined to measure the importance of ReLU Softmax and enable the selection between the two attention variants with different structure granularities (§4.2). Then, we propose an MPC-aware differentiable NAS algorithm to learn the architecture parameters and model parameters simultaneously. We select between the attention variants based on the architecture parameters and the latency constraints (§4.3). In the last step, we retrain the ViT with heterogeneous attentions from scratch. We leverage knowledge distillation (KD) to improve the accuracy of the searched networks (§4.4). Appendix D depicts the complete algorithm flow of MPCViT." + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.091, + 0.89, + 0.259 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.53, + 0.261, + 0.856, + 0.276 + ], + "angle": 0, + "content": "Figure 4. Overview of our proposed MPCViT pipeline." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.297, + 0.833, + 0.314 + ], + "angle": 0, + "content": "4.2. Heterogeneous Attention Search Space" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.321, + 0.891, + 0.381 + ], + "angle": 0, + "content": "Our heterogeneous search space combines two candidate attention variants, i.e., MPC-efficient ScaleAttn and high-accuracy RSAAttn and has the following three different structural granularities as shown in Figure 5:" + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.387, + 0.891, + 0.448 + ], + "angle": 0, + "content": "- Layer-wise search space is coarse-grained, with each layer using either ScaleAttn or RSAattn. The total number of possible architectures in the search space can be limited, especially for shallow ViT models." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.456, + 0.89, + 0.485 + ], + "angle": 0, + "content": "- Head-wise search space selects ScaleAttn or RSAAttn for each attention head of each layer." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.495, + 0.891, + 0.54 + ], + "angle": 0, + "content": "- Row-wise search space (i.e., token-wise) is the most fine-grained and mixes the two attention variants along each row of the attention map." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.387, + 0.891, + 0.54 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.547, + 0.89, + 0.607 + ], + "angle": 0, + "content": "Though the search spaces have different granularities, they share very similar NAS formulation. In the rest of the explanation, we will use the head-wise search space as an example to explain our algorithm." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.615, + 0.783, + 0.63 + ], + "angle": 0, + "content": "4.3. MPC-Aware Differentiable NAS" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.638, + 0.891, + 0.743 + ], + "angle": 0, + "content": "Many research efforts have been made to NAS including reinforcement learning method (RL) [17, 24, 57], however, RL-based NAS requires significant overhead during searching. Recent years, [10, 27, 55, 61] explore hardware-aware NAS algorithms to make model fit the rigorous hardware requirement. For private ViT inference, we also need a NAS algorithm that takes MPC conditions into consideration." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.744, + 0.89, + 0.788 + ], + "angle": 0, + "content": "Given the heterogeneous attention search space, we now introduce our simple yet effective MPC-aware differentiable NAS algorithm." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.789, + 0.891, + 0.864 + ], + "angle": 0, + "content": "Search formulation. Inspired by [5], we introduce an architecture parameter \\(\\alpha\\) (\\(0 \\leq \\alpha \\leq 1\\)) for each head, which is an auxiliary learnable variable that helps to choose between RSAAtt and ScaleAttn. Then, each head implements the computation below:" + }, + { + "type": "equation", + "bbox": [ + 0.5, + 0.87, + 0.894, + 0.906 + ], + "angle": 0, + "content": "\\[\n\\alpha \\cdot \\operatorname {R e L U S o f t m a x} \\left(\\frac {Q K ^ {T}}{\\sqrt {d _ {k}}}\\right) V + (1 - \\alpha) \\cdot \\frac {\\operatorname {S c a l e A t t n} (Q , K , V)}{\\sqrt {d _ {k}}}.\n\\]" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5056" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.089, + 0.468, + 0.234 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.237, + 0.47, + 0.32 + ], + "angle": 0, + "content": "Figure 5. An illustration of our proposed search space with different structure granularities: (a) layer-wise search space with the size of \\(2^{\\# \\text{layers}}\\); (b) head-wise search space with the size of \\(2^{\\# \\text{layers} \\times \\# \\text{heads}}\\) and; (c) row-wise search space with the size of \\(2^{\\# \\text{layers} \\times \\# \\text{heads} \\times \\# \\text{tokens}}\\). The blocks in blue represent RSAAttn and the blocks in grey represent ScaleAttn." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.345, + 0.469, + 0.376 + ], + "angle": 0, + "content": "Note that we also add \\(\\frac{1}{\\sqrt{d_k}}\\) for ScaleAttn to make the search process more stable and robust." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.377, + 0.469, + 0.483 + ], + "angle": 0, + "content": "Search objective function. We aim at training ViTs with high accuracy but as few RSAattn as possible. We introduce \\(\\ell 1\\)-penalty into the objective function and formulate the NAS as a one-level optimization problem. To take MPC overhead into consideration, we incorporate realistic inference latency constraints into objective function to construct the MPC-aware NAS algorithm as" + }, + { + "type": "equation", + "bbox": [ + 0.158, + 0.495, + 0.388, + 0.513 + ], + "angle": 0, + "content": "\\[\n\\mathrm {C o s t} (\\alpha_ {i j}) = \\alpha_ {i j} \\cdot \\mathrm {L a t (A T T N} _ {i j}),\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.116, + 0.516, + 0.432, + 0.557 + ], + "angle": 0, + "content": "\\[\n\\min _ {\\theta , \\alpha} \\ell (f _ {\\theta , \\alpha} (x), y) + \\lambda \\cdot (\\sum_ {i = 1} ^ {L} \\sum_ {j = 1} ^ {N} \\| \\operatorname {C o s t} (\\alpha_ {i j}) \\| _ {1}),\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.569, + 0.469, + 0.719 + ], + "angle": 0, + "content": "where \\( x \\) and \\( y \\) are the input-label pairs, \\( \\ell(\\cdot) \\) is the loss function, \\( \\lambda \\) is a hyper-parameter to control the weight of inference overhead, \\( N \\) is the number of heads in one layer, and \\( L \\) is the number of layers. \\( \\| \\cdot \\|_1 \\) means \\( \\ell 1 \\)-norm, and \\( \\mathrm{ATTN}_{ij} \\) means the candidate attention of \\( i \\)-th layer and \\( j \\)-th head. We initialize \\( \\alpha \\) for each head to 1.0 and jointly optimize the network parameter \\( \\theta \\) and architecture parameter \\( \\alpha \\) during searching. Note that our differentiable algorithm computes the gradients of \\( \\alpha \\) for all the attention heads across different layers in ViT simultaneously." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.469, + 0.901 + ], + "angle": 0, + "content": "Architecture parameter binarization. After the network searching, we obtain \\(\\alpha\\) for each attention head in all layers. To select either RSAattn or ScaleAttn for each head, we binarize \\(\\alpha\\) based on the following rule: we use the top-\\(k\\) rule according to the ratio of RSAattn budgeet \\(\\mu\\), which is defined as \\(\\# \\text{RSAattn} / \\# \\text{Heads}\\). Specifically, we first find the \\(\\mu L N\\)-th largest \\(\\alpha\\), denoted as \\(\\alpha^{*}\\), and then we binarize \\(\\alpha\\) for each attention head following \\(\\mathbb{1}(\\alpha \\geq \\alpha^{*})\\). Our proposed search method does not need to train candidate networks, but only needs to train once and then select, which accelerates our search process. Now, we obtain a heterogeneous ViT, and by changing \\(\\mu\\), we can obtain a family of" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.092, + 0.892, + 0.213 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.215, + 0.892, + 0.241 + ], + "angle": 0, + "content": "Figure 6. MPCViT+: The optimization of our proposed GeLU linearization and linear fusion for the MLP block." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.266, + 0.851, + 0.281 + ], + "angle": 0, + "content": "ViTs with different accuracy and efficiency trade-off." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.292, + 0.892, + 0.307 + ], + "angle": 0, + "content": "4.4. Train the Searched ViT for Better Performance" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.315, + 0.892, + 0.39 + ], + "angle": 0, + "content": "After binarization, RSAattn with a small \\(\\alpha\\) are replaced with ScaleAttn. We find that directly training a heterogeneous ViT results in an accuracy drop. So, how to effectively train the heterogeneous ViT and restore the model accuracy is an important question for us." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.391, + 0.893, + 0.618 + ], + "angle": 0, + "content": "Token-wise feature-based KD. KD [21] is a powerful tool for a student network to learn from a teacher network, which is usually larger and more complex with a higher learning capacity. To improve the accuracy of MPCViT, we leverage token-wise feature-based self-distillation along with a logits-based KD, which uses the baseline ViT as the teacher network while other larger networks can be easily plugged in and used in our framework. For the feature-based KD, we take the output features of the last ViT layer from both the student and the teacher networks and compute the \\(\\ell 2\\)-distance, denoted as \\(\\mathcal{L}_{\\text {feature }}\\). We also use KL-divergence loss \\(\\mathcal{L}_{KL}\\) for the logits-based KD, denoted as \\(\\mathcal{L}_{\\text {logits }}\\). Combining distillation loss with the task-specific cross-entropy (CE) loss \\(\\mathcal{L}_{CE}\\), we obtain the final training objective under a distillation temperature \\(\\mathcal{T}\\) as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.505, + 0.63, + 0.886, + 0.677 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {L} _ {\\text {t r a i n}} = \\chi \\mathcal {L} _ {C E} + \\beta \\mathcal {L} _ {\\text {l o g i t s}} + \\gamma \\mathcal {L} _ {\\text {f e a t u r e}} \\\\ = \\chi \\mathcal {L} _ {C E} + \\beta \\mathcal {L} _ {K L} (\\sigma (\\frac {z _ {s}}{\\mathcal {T}}), \\sigma (\\frac {z _ {t}}{\\mathcal {T}})) + \\gamma \\| z _ {s} - z _ {t} \\| _ {2}, \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.686, + 0.892, + 0.777 + ], + "angle": 0, + "content": "where \\(\\chi, \\beta\\) and \\(\\gamma\\) are training hyper-parameters to balance different loss functions in the training objective, \\(z_{s}\\) and \\(z_{t}\\) are feature maps from student and teacher, and \\(\\sigma\\) is Softmax. This self-distillation requires no extra model and only introduces negligible training cost, and has no influence on inference latency or communication overhead in MPC." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.787, + 0.879, + 0.803 + ], + "angle": 0, + "content": "4.5. MPCViT+: Support for GeLU Linearization" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.892, + 0.901 + ], + "angle": 0, + "content": "The above design of MPCViT leverages NAS algorithm to build the efficient yet effective attention mechanism. Besides attention, in MLP blocks, non-linear GeLU also impacts the communication cost in some protocols, e.g., Cheetah when the number of heads or tokens is small. And two linear layers near GeLU are also costly because" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5057" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.198 + ], + "angle": 0, + "content": "the inverted-bottleneck structure of MLP leads to high-dimensional MatMul, which is shown in Figure 1 and Figure 3(a). To further improve the efficiency of ViTs, we propose an extended version called MPCViT+. Specifically, MPCViT+ searches and removes relatively \"unimportant\" GeLUs. Given architecture parameter \\(\\beta\\) for GeLU, the NAS algorithm is similar to the attention optimization:" + }, + { + "type": "equation", + "bbox": [ + 0.159, + 0.209, + 0.388, + 0.226 + ], + "angle": 0, + "content": "\\[\n(\\beta \\cdot \\operatorname {G e L U} (x) + (1 - \\beta) \\cdot x) \\cdot \\mathscr {W}.\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.235, + 0.47, + 0.288 + ], + "angle": 0, + "content": "The architecture parameters \\(\\alpha\\) and \\(\\beta\\) are jointly learnt during the search, thus the NAS loss is defined along with the classification loss \\(\\min_{\\theta ,\\alpha ,\\beta}\\ell (f_{\\theta ,\\alpha ,\\beta}(x),y)\\) .." + }, + { + "type": "equation", + "bbox": [ + 0.172, + 0.3, + 0.376, + 0.317 + ], + "angle": 0, + "content": "\\[\n\\operatorname {C o s t} \\left(\\beta_ {i j}\\right) = \\beta_ {i j} \\cdot \\operatorname {L a t} \\left(\\operatorname {A c t} _ {i j}\\right),\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.084, + 0.32, + 0.462, + 0.362 + ], + "angle": 0, + "content": "\\[\n\\lambda \\cdot (\\sum_ {i = 1} ^ {L} \\sum_ {j = 1} ^ {N} \\| \\operatorname {C o s t} \\left(\\alpha_ {i j}\\right) \\| _ {1}) + \\eta \\cdot (\\sum_ {i = 1} ^ {L} \\sum_ {j = 1} ^ {T} \\| \\operatorname {C o s t} \\left(\\beta_ {i j}\\right) \\| _ {1}),\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.372, + 0.47, + 0.45 + ], + "angle": 0, + "content": "here, we take token-wise linearization as an example, and \\(\\mathrm{Lat}(\\mathrm{Act}_{\\mathrm{ij}})\\) denotes the latency of either GeLU or identity of \\(i\\)-th layer and \\(j\\)-th token, \\(T\\) denotes the number of tokens in each layer. We can consider the balance between \\(\\lambda\\) and \\(\\eta\\) through the private inference latency: \\(\\frac{\\lambda}{\\eta} = \\frac{\\mathrm{Lat}(\\mathrm{ATTN})}{\\mathrm{Lat}(\\mathrm{GELU})}\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.451, + 0.47, + 0.697 + ], + "angle": 0, + "content": "Fuse two linear layers together. After GeLU linearization, we observe an opportunity for further latency reduction. As shown in Figure 6, we fuse the linear layer before and after GeLU of a certain token, which reduces the communication associated with the MLP. Denote the input of a MLP block of \\(i\\)-th layer as \\(X^{(i)} \\in \\mathbb{R}^{B \\times H \\times W \\times C}\\), the linear layers as \\(\\mathcal{W}_1^{(i)} \\in \\mathbb{R}^{C \\times K}\\) and \\(\\mathcal{W}_2^{(i)} \\in \\mathbb{R}^{K \\times C}\\), the output of MLP as \\(X^{(i+1)} \\in \\mathbb{R}^{B \\times H \\times W \\times C}\\). The input dimension of GeLU is \\(B \\times H \\times W \\times K\\), and \\(C, K\\) are channel numbers of linear layers. Note that we generally set the ratio of MLP (i.e., \\(\\frac{K}{C}\\)) to 2 or 4 in ViT models. The linearized MLP can be formulated as \\(X^{(i+1)} = (X^{(i)}\\mathcal{W}_1^{(i)})\\mathcal{W}_2^{(i)} = X^{(i)}(\\mathcal{W}_1^{(i)}\\mathcal{W}_2^{(i)})\\). In this way, \\(\\mathcal{W}_1^{(i)}\\mathcal{W}_2^{(i)}\\) is fused into \\(\\mathcal{W}_f^{(i)} \\in \\mathbb{R}^{C \\times C}\\), which optimizes two high-dimensional MatMuls to only a single low-dimensional MatMul, further reducing the latency of MLP." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.697, + 0.469, + 0.773 + ], + "angle": 0, + "content": "Adding additional activations. After GeLU removal and linear fusion, there is no non-linearity in these tokens. To boost the accuracy, we additionally add a non-linear function after the fused linear positions. Here, we choose to add ReLU which incurs a cheaper cost than GeLU." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.785, + 0.21, + 0.803 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.81, + 0.267, + 0.827 + ], + "angle": 0, + "content": "5.1. Experimental Setup" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.833, + 0.469, + 0.88 + ], + "angle": 0, + "content": "Experimental and MPC settings. In our experiments, we leverage the SecretFlow (SPU [39] V0.3.1b0)2 framework for private inference, which is popular for privacy-" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.092, + 0.892, + 0.197 + ], + "angle": 0, + "content": "preserving deep learning. We adopt the SEMI-2K [9] protocol, which is a semi-honest two-party computation protocol3. We follow Cheetah [22] and use the WAN mode for communication. Specifically, the communication bandwidth between the cloud instances is set to 44 MBps and the round-trip time is set to 40ms. Our experiments are evaluated on an Intel Xeon CPU@2.40 GHz with 62 GB RAM." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.198, + 0.893, + 0.318 + ], + "angle": 0, + "content": "Model architectures and datasets. Many researches have studied training ViTs on small datasets [12, 19, 23, 32, 35]. We consider two ViT architectures on three commonly used datasets following [19]. For the CIFAR-10/100 dataset, we set the ViT depth, # heads, hidden dimension, and patch size to 7, 4, 256, and 4, respectively. For TinyImageNet dataset, we set the ViT depth, # heads, hidden dimension, and patch size to 9, 12, 192, and 4, respectively." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.318, + 0.892, + 0.378 + ], + "angle": 0, + "content": "Searching settings. We run the NAS algorithm for 300 epochs with AdamW optimizer and a cosine learning rate across three datasets. We set \\(\\epsilon = 10^{-8}\\) to avoid the zero denominator in RSAatt, and \\(\\lambda = 10^{-5}\\)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.379, + 0.892, + 0.47 + ], + "angle": 0, + "content": "Training settings. Following [19], we train the searched heterogeneous ViTs for 600 epochs on CIFAR-10/100 and 300 epochs on Tiny/ImageNet. We leverage data augmentations as [19]. For KD, we set the temperature \\(\\mathcal{T}\\) to 1, and set \\(\\chi, \\beta, \\gamma\\) to 1 as well. To explore the trade-off between inference accuracy and latency, we set \\(\\mu\\) to \\(\\{0.1, 0.3, 0.5, 0.7\\}\\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.478, + 0.892, + 0.494 + ], + "angle": 0, + "content": "5.2. Comparison with Prior-Art Efficient Attentions" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.501, + 0.892, + 0.637 + ], + "angle": 0, + "content": "Baselines. We compare MPCViT with prior-art models on the inference accuracy and efficiency. We compare with MPCFormer [33], Linformer [58, 60], THE-X [6] and ViT variants in Table 2. Linformer is studied in [60] as an efficient Transformer variant for MPC and the compression rate of attention dimension is also defined as \\(\\mu\\). For networks compared with MPCViT, we only modify attention layer and keep MLP unchanged as the baseline ViT. For \\(\\mathrm{MPCViT^{+}}\\), we optimize attention and MLP simultaneously." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.638, + 0.892, + 0.697 + ], + "angle": 0, + "content": "Results and analysis. The main results are shown in Figure 7, where we report top-1 accuracy across three datasets and the network inference latency. The main findings are as follows:" + }, + { + "type": "text", + "bbox": [ + 0.512, + 0.706, + 0.892, + 0.797 + ], + "angle": 0, + "content": "1) MPCViT outperforms prior-art methods. Without KD, on Tiny-ImageNet, MPCViT with \\(\\mu = 0.1\\) outperforms Linformer with \\(\\mu = 0.7\\) by \\(0.57\\%\\) better accuracy with \\(4.9\\times\\) latency reduction; Compared with THE-X, MPCViT achieve \\(3.6\\%\\) accuracy improvement with \\(1.9\\times\\) latency reduction;" + }, + { + "type": "text", + "bbox": [ + 0.51, + 0.806, + 0.892, + 0.868 + ], + "angle": 0, + "content": "2) with proper KD, MPCViT even achieves \\(1.9\\%\\) and \\(1.3\\%\\) better accuracy with \\(6.2 \\times\\) and \\(2.9 \\times\\) latency reduction with \\(\\mu = 0.1\\) and 0.3, compared with baseline ViT and MPCFormer on Tiny-ImageNet, respectively;" + }, + { + "type": "list", + "bbox": [ + 0.51, + 0.706, + 0.892, + 0.868 + ], + "angle": 0, + "content": null + }, + { + "type": "page_footnote", + "bbox": [ + 0.5, + 0.875, + 0.892, + 0.901 + ], + "angle": 0, + "content": "3 Although the actual latency of each operator may be different for different MPC protocols, our proposed algorithm can be generally applied." + }, + { + "type": "page_footnote", + "bbox": [ + 0.094, + 0.887, + 0.42, + 0.9 + ], + "angle": 0, + "content": "2https://github.com/secretflow/secretflow" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5058" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.102, + 0.09, + 0.357, + 0.253 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.359, + 0.091, + 0.613, + 0.252 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.615, + 0.091, + 0.872, + 0.252 + ], + "angle": 0, + "content": null + }, + { + "type": "image_footnote", + "bbox": [ + 0.283, + 0.254, + 0.723, + 0.263 + ], + "angle": 0, + "content": "- MPCViT w/o KD (ours) - MPCViT w/ KD (ours) Linformer - ReLU Softmax ViT - ScaleAttn ViT - THE-X" + }, + { + "type": "image_footnote", + "bbox": [ + 0.304, + 0.267, + 0.698, + 0.277 + ], + "angle": 0, + "content": "Softmax-ScaleAttn ViT Softmax ViT MPCViT w/ Per-layer Search MPCFormer w/KD MPFCorner w/o KD" + }, + { + "type": "list", + "bbox": [ + 0.283, + 0.254, + 0.723, + 0.277 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.185, + 0.286, + 0.782, + 0.301 + ], + "angle": 0, + "content": "Figure 7. Top-1 Accuracy and inference latency comparison with baseline ViTs across three datasets." + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.324, + 0.47, + 0.444 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.447, + 0.47, + 0.474 + ], + "angle": 0, + "content": "Figure 8. Latency and communication cost comparison of different layers in the 9-layer 12-head ViT with \\(\\mu = 0.5\\)." + }, + { + "type": "text", + "bbox": [ + 0.088, + 0.484, + 0.47, + 0.545 + ], + "angle": 0, + "content": "3) we mix Softmax attention and ScaleAttn. Although it has a slightly higher accuracy in plaintext inference, it incurs at least \\(1.4 \\times\\) and \\(1.2 \\times\\) latency on CIFAR-10/100 and Tiny/ImageNet compared with MPCViT." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.552, + 0.47, + 0.658 + ], + "angle": 0, + "content": "We visualize the latency and communication cost comparison of Softmax ViT, ReLU Softmax ViT, and MPCViT in Figure 8. We can observe the latency changes proportionally with the communication. Also, we observe for MPCViT, RSAattn in middle layers (e.g., layer 2 to layer 5) tend to be preserved while RSAattn in early and final layers are likely to be replaced with ScaleAttn." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.665, + 0.418, + 0.681 + ], + "angle": 0, + "content": "5.3. Comparison on Structure Granularities" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.688, + 0.469, + 0.84 + ], + "angle": 0, + "content": "The choice of search space is important for MPCViT, so we compare different structure granularities of search space proposed in §4.2. We use the CIFAR-10 dataset for the comparison. As shown in Table 3, the head-wise search space achieves the best accuracy. We hypothesize although rowwise structure leads to the largest search space, such a fine-grained search space may introduce difficulties in NAS, and hence, leads to network architecture with inferior accuracy. Head-wise search space achieves the right balance between flexibility and optimizability." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.848, + 0.325, + 0.863 + ], + "angle": 0, + "content": "5.4. Ablation Study of MPCViT" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Contribution of KD. One of our key techniques for training heterogeneous ViT is KD. We enumerate different" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.322, + 0.892, + 0.349 + ], + "angle": 0, + "content": "Table 3. Top-1 accuracy (%) comparison with different structure granularities of attention search space with different \\( \\mu \\) ." + }, + { + "type": "table", + "bbox": [ + 0.552, + 0.35, + 0.846, + 0.399 + ], + "angle": 0, + "content": "
GranularityLayer-wiseRow-wiseHead-wise
μ = 0.593.0193.1693.21
μ = 0.793.3293.1393.38
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.413, + 0.891, + 0.44 + ], + "angle": 0, + "content": "Table 4. Top-1 Accuracy \\((\\%)\\) comparison of different combinations of training loss function with \\(\\mu = 0.7\\)" + }, + { + "type": "table", + "bbox": [ + 0.525, + 0.441, + 0.866, + 0.507 + ], + "angle": 0, + "content": "
CELogits-based KDFeature-based KDCIFAR-10Tiny-ImageNet
✓93.3859.02
✓✓94.1862.39
✓✓94.1262.26
✓✓94.1461.80
✓✓✓94.2763.03
" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.535, + 0.892, + 0.641 + ], + "angle": 0, + "content": "combinations of KD and the results are shown in Table 4. We find that: 1) both logits-based and feature-based KD significantly improve the performance of ViT compared to using cross-entropy loss only; and 2) combining the two KD losses further improves the accuracy, especially on a larger dataset. The above findings indicate the importance of KD and the indispensability of three parts of \\(\\mathcal{L}_{train}\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.643, + 0.893, + 0.853 + ], + "angle": 0, + "content": "Consistency and scalability of NAS algorithm. We hope our NAS algorithm to be robust against hyperparameter choices and datasets. To analyze this consistency of our algorithm, we adjust the coefficient \\(\\lambda\\) to three different values, i.e., \\(10^{-3}, 10^{-4}, 10^{-5}\\), and train a 7-layer ViT with 4 heads. We visualize the distribution of the architecture parameter \\(\\alpha\\) in Figure 9, and we find that \\(\\alpha\\) in each layer has a quite similar trend under different \\(\\lambda\\)'s. Furthermore, when we change the number of heads to 8, or even train the same architecture on different datasets like CIFAR-100 and ImageNet, the distribution still shows a similar trend, empirically proving the consistency and scalability of our proposed NAS algorithm. Appendix F shows more distribution trends under other settings." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Comparison with per-layer search. We also compare MPCViT with per-layer search which replaces RSA ttn heads in each layer uniformly given a certain \\(\\mu\\) across three" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5059" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.091, + 0.473, + 0.216 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.217, + 0.47, + 0.34 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.343, + 0.47, + 0.386 + ], + "angle": 0, + "content": "Figure 9. The distribution of architecture parameter \\(\\alpha\\) for each head under different \\(\\lambda\\) and different # heads on different datasets. We draw the average \\(\\alpha\\) in each layer to show the similar trend." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.409, + 0.47, + 0.469 + ], + "angle": 0, + "content": "datasets. As shown in Figure 7, MPCViT achieves a better Pareto front for accuracy and efficiency compared to the per-layer NAS. The results demonstrate the importance to search and replace RSAtn heads across different layers." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.478, + 0.283, + 0.492 + ], + "angle": 0, + "content": "5.5. MPCViT+ Evaluation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.501, + 0.47, + 0.697 + ], + "angle": 0, + "content": "As shown in Figure 7, when \\(\\mu\\) decreases to 0.1, the major latency bottleneck comes from GeLU in MLP. We evaluate MPCViT+ for GeLU reduction on CIFAR-10/100 datasets with KD, which correspond to the ViT models with significant GeLU latency. We take token-wise optimization as an example (exploration for other granularity, i.e., layer-wise is shown in Appendix E), and control the GeLU linearization rate using a threshold \\(\\sigma\\) such that \\(\\beta \\leftarrow 0(\\beta \\leq \\sigma)\\) while \\(\\beta \\leftarrow 1(\\beta >\\sigma)\\). As shown in Figure 10, GeLU linearization leads to a little accuracy degradation, indicating that GeLU plays an important role in ViTs. MPCViT+ further reduces the latency on the basis of attention optimization, which proves the effectiveness of MPCViT+." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.697, + 0.47, + 0.788 + ], + "angle": 0, + "content": "Ablation study of additional ReLU. To analyze the help of adding additional ReLU after the fused linear layer, we fix \\(\\sigma = 0.75\\) and perform the ablation study for MPCViT\\(^{+}\\) under different latency constraints on CIFAR-10 dataset in Table 5. The results show that additional ReLU improves the representation ability of MPCViT\\(^{+}\\)." + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.798, + 0.469, + 0.825 + ], + "angle": 0, + "content": "Table 5. Ablation study of adding additional ReLU after the fused linear layer under different latency constraints." + }, + { + "type": "table", + "bbox": [ + 0.1, + 0.825, + 0.451, + 0.884 + ], + "angle": 0, + "content": "
μ0.30.7
Accuracy (%)Latency (s)Accuracy (%)Latency (s)
MPCViT+93.9243.8894.2754.56
w/o ReLU93.7241.3793.8152.11
" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.091, + 0.696, + 0.212 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.697, + 0.091, + 0.89, + 0.212 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.52, + 0.216, + 0.866, + 0.23 + ], + "angle": 0, + "content": "Figure 10. Comparison between MPCViT and MPCViT+." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.255, + 0.619, + 0.271 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.282, + 0.892, + 0.448 + ], + "angle": 0, + "content": "In this paper, we present an MPC-friendly ViT family, dubbed MPCViT, to enable accurate yet efficient ViT inference in MPC. We propose a heterogeneous attention optimization space, and design an MPC-aware differentiable NAS algorithm to explore the search space. To further boost the inference efficiency, we propose \\(\\mathrm{MPCViT^{+}}\\) to jointly optimize attention and MLP. Extensive experiments demonstrate that MPCViT consistently outperforms prior-art ViT architectures with both lower latency and higher accuracy. Our method can be further applied to large language models (LLMs) including BERT and GPT." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.464, + 0.66, + 0.48 + ], + "angle": 0, + "content": "Acknowledgement" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.49, + 0.891, + 0.52 + ], + "angle": 0, + "content": "This work is supported in part by the NSFC (62125401) and the 111 Project (B18001)." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.536, + 0.597, + 0.551 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.508, + 0.561, + 0.892, + 0.601 + ], + "angle": 0, + "content": "[1] Saba Akram and Quarrat Ul Ann. Newton raphson method. International Journal of Scientific & Engineering Research, 6(7):1748-1752, 2015. 13" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.602, + 0.894, + 0.669 + ], + "angle": 0, + "content": "[2] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In Proceedings of the IEEE/CVF international conference on computer vision, pages 6836-6846, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.669, + 0.895, + 0.737 + ], + "angle": 0, + "content": "[3] Gilad Asharov, Yehuda Lindell, Thomas Schneider, and Michael Zohner. More efficient oblivious transfer and extensions for faster secure computation. In ACM SIGSAC conference on Computer & Communications Security (CCS), pages 535-548, 2013. 14" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.738, + 0.894, + 0.792 + ], + "angle": 0, + "content": "[4] Daniel Bolya, Cheng-Yang Fu, Xiaoliang Dai, Peizhao Zhang, and Judy Hoffman. Hydra attention: Efficient attention with many heads. In European Conference on Computer Vision, pages 35-49. Springer, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.792, + 0.892, + 0.832 + ], + "angle": 0, + "content": "[5] Jason Ross Brown, Yiren Zhao, Ilia Shumailov, and Robert D Mullins. Dartformer: Finding the best type of attention. arXiv preprint arXiv:2210.00641, 2022. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.832, + 0.895, + 0.902 + ], + "angle": 0, + "content": "[6] Tianyu Chen, Hangbo Bao, Shaohan Huang, Li Dong, Binxing Jiao, Daxin Jiang, Haoyi Zhou, Jianxin Li, and Furu Wei. THE-X: Privacy-preserving transformer inference with homomorphic encryption. In Findings of the Association for Computational Linguistics: ACL 2022, pages 3510-3520," + }, + { + "type": "list", + "bbox": [ + 0.508, + 0.561, + 0.895, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "5060" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.109, + 0.092, + 0.469, + 0.12 + ], + "angle": 0, + "content": "Dublin, Ireland, May 2022. Association for Computational Linguistics. 2, 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.12, + 0.47, + 0.173 + ], + "angle": 0, + "content": "[7] Minsu Cho, Zahra Ghodsi, Brandon Reagen, Siddharth Garg, and Chinmay Hegde. Sphynx: Relu-efficient network design for private inference. arXiv preprint arXiv:2106.11755, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.173, + 0.469, + 0.228 + ], + "angle": 0, + "content": "[8] Minsu Cho, Ameya Joshi, Brandon Reagen, Siddharth Garg, and Chinmay Hegde. Selective network linearization for efficient private inference. In International Conference on Machine Learning, pages 3947-3961. PMLR, 2022. 3, 15" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.228, + 0.469, + 0.282 + ], + "angle": 0, + "content": "[9] Ronald Cramer, Ivan Damgård, Daniel Escudero, Peter Scholl, and Chaoping Xing. SpdZ2k: Efficient mpc mod 2k for dishonest majority. In Annual International Cryptology Conference. Springer, pages 769-798, 2018. 4, 7, 13" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.282, + 0.469, + 0.363 + ], + "angle": 0, + "content": "[10] Xiaoliang Dai, Peizhao Zhang, Bichen Wu, Hongxu Yin, Fei Sun, Yanghan Wang, Marat Dukhan, Yunqing Hu, Yiming Wu, Yangqing Jia, et al. Chamnet: Towards efficient network design through platform-aware model adaptation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11398-11407, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.363, + 0.469, + 0.473 + ], + "angle": 0, + "content": "[11] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In 9th International Conference on Learning Representations, ICLR 2021, Virtual Event, Austria, May 3-7, 2021. OpenReview.net, 2021. 1, 2, 4, 13" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.473, + 0.469, + 0.514 + ], + "angle": 0, + "content": "[12] Hanan Gani, Muzammal Naseer, and Mohammad Yaqub. How to train vision transformer on small-scale datasets? arXiv preprint arXiv:2210.07240, 2022. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.514, + 0.469, + 0.568 + ], + "angle": 0, + "content": "[13] Zahra Ghodsi, Akshaj Kumar Veldanda, Brandon Reagen, and Siddharth Garg. Cryptonas: Private inference on a relu budget. Advances in Neural Information Processing Systems, 33:16961-16971, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.568, + 0.469, + 0.593 + ], + "angle": 0, + "content": "[14] Oded Goldreich. Secure multi-party computation. 1998. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.593, + 0.469, + 0.662 + ], + "angle": 0, + "content": "[15] Chengyue Gong, Dilin Wang, Meng Li, Xinlei Chen, Zhicheng Yan, Yuandong Tian, Vikas Chandra, et al. Nasvit: Neural architecture search for efficient vision transformers with gradient conflict aware supernet training. In International Conference on Learning Representations, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.662, + 0.469, + 0.743 + ], + "angle": 0, + "content": "[16] Jiaqi Gu, Hyoukjun Kwon, Dilin Wang, Wei Ye, Meng Li, Yu-Hsin Chen, Liangzhen Lai, Vikas Chandra, and David Z Pan. Multi-scale high-resolution vision transformer for semantic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12094-12103, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.743, + 0.469, + 0.811 + ], + "angle": 0, + "content": "[17] Minghao Guo, Zhao Zhong, Wei Wu, Dahua Lin, and Junjie Yan. Irlas: Inverse reinforcement learning for architecture search. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9021-9029, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.811, + 0.469, + 0.866 + ], + "angle": 0, + "content": "[18] Meng Hao, Hongwei Li, Hanxiao Chen, Pengzhi Xing, Guowen Xu, and Tianwei Zhang. Iron: Private inference on transformers. Advances in neural information processing systems, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.866, + 0.469, + 0.893 + ], + "angle": 0, + "content": "[19] Ali Hassani, Steven Walton, Nikhil Shah, Abulikemu Abuduweili, Jiachen Li, and Humphrey Shi. Escaping the" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.893 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "big data paradigm with compact transformers. arXiv preprint arXiv:2104.05704, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.12, + 0.892, + 0.147 + ], + "angle": 0, + "content": "[20] Dan Hendrycks and Kevin Gimpel. Gaussian error linear units (gelus). arXiv preprint arXiv:1606.08415, 2016. 13" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.147, + 0.892, + 0.186 + ], + "angle": 0, + "content": "[21] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, et al. Distilling the knowledge in a neural network. arXiv preprint arXiv:1503.02531, 2(7), 2015. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.186, + 0.892, + 0.254 + ], + "angle": 0, + "content": "[22] Zhicong Huang, Wen jie Lu, Cheng Hong, and Jiansheng Ding. Cheetah: Lean and fast secure Two-Party deep neural network inference. In USENIX Security Symposium (USENIX Security), pages 809–826, Boston, MA, Aug. 2022. 4, 7, 13" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.254, + 0.892, + 0.281 + ], + "angle": 0, + "content": "[23] Ethan Huynh. Vision transformers in 2022: An update on tiny imagenet. arXiv preprint arXiv:2205.10660, 2022. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.281, + 0.892, + 0.334 + ], + "angle": 0, + "content": "[24] Yesmina JAAFra, Jean Luc Laurent, Aline Deruyver, and Mohamed Saber Naceur. Reinforcement learning for neural architecture search: A review. Image and Vision Computing, 89:57-66, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.334, + 0.892, + 0.389 + ], + "angle": 0, + "content": "[25] Nandan Kumar Jha, Zahra Ghodsi, Siddharth Garg, and Brandon Reagen. Deepreduce: Relu reduction for fast private inference. In International Conference on Machine Learning, pages 4839-4849. PMLR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.389, + 0.892, + 0.43 + ], + "angle": 0, + "content": "[26] Nandan Kumar Jha and Brandon Reagen. Deepreshape: Redesigning neural networks for efficient private inference. arXiv preprint arXiv:2304.10593, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.43, + 0.892, + 0.509 + ], + "angle": 0, + "content": "[27] Weiwen Jiang, Lei Yang, Edwin Hsing-Mean Sha, Qingfeng Zhuge, Shouzhen Gu, Sakyasingha Dasgupta, Yiyu Shi, and Jingtong Hu. Hardware/software co-exploration of neural architectures. IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 39(12):4805-4815, 2020. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.51, + 0.892, + 0.566 + ], + "angle": 0, + "content": "[28] Jacob Devlin Ming-Wei Chang Kenton and Lee Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of naacL-HLT, volume 1, page 2, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.566, + 0.892, + 0.632 + ], + "angle": 0, + "content": "[29] Nikita Kitaev, Lukasz Kaiser, and Anselm Levskaya. Reformer: The efficient transformer. In 8th International Conference on Learning Representations, ICLR 2020, Addis Ababa, Ethiopia, April 26-30, 2020. OpenReview.net, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.632, + 0.892, + 0.701 + ], + "angle": 0, + "content": "[30] Brian Knott, Shobha Venkataraman, Awni Hannun, Shubho Sengupta, Mark Ibrahim, and Laurens van der Maaten. Crypten: Secure multi-party computation meets machine learning. Advances in Neural Information Processing Systems, 34:4961-4973, 2021. 13" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.701, + 0.892, + 0.782 + ], + "angle": 0, + "content": "[31] Souvik Kundu, Shunlin Lu, Yuke Zhang, Jacqueline Tiffany Liu, and Peter A. Beerel. Learning to linearize deep neural networks for secure and efficient private inference. In The Eleventh International Conference on Learning Representations, ICLR 2023, Kigali, Rwanda, May 1-5, 2023. OpenReview.net, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.782, + 0.892, + 0.823 + ], + "angle": 0, + "content": "[32] Seunghoon Lee, Seunghyun Lee, and Byung Cheol Song. Improving vision transformers to learn small-size dataset from scratch. IEEE Access, 10:123212-123224, 2022. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.823, + 0.892, + 0.893 + ], + "angle": 0, + "content": "[33] Dacheng Li, Hongyi Wang, Rulin Shao, Han Guo, Eric P. Xing, and Hao Zhang. MPCFORMER: fast, performant and provate transformer inference with MPC. In The Eleventh International Conference on Learning Representations, ICLR 2023, Kigali, Rwanda, May 1-5, 2023. OpenReview.net," + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.893 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "5061" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.111, + 0.092, + 0.227, + 0.105 + ], + "angle": 0, + "content": "2023. 2, 3, 4, 7, 14" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.106, + 0.469, + 0.146 + ], + "angle": 0, + "content": "[34] Zhexin Li, Tong Yang, Peisong Wang, and Jian Cheng. Q-vit: Fully differentiable quantization for vision transformer. arXiv preprint arXiv:2201.07703, 2022. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.147, + 0.469, + 0.2 + ], + "angle": 0, + "content": "[35] Yahui Liu, Enver Sangineto, Wei Bi, Nicu Sebe, Bruno Lepri, and Marco Nadai. Efficient training of visual transformers with small datasets. Advances in Neural Information Processing Systems, 34:23818-23830, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.201, + 0.469, + 0.254 + ], + "angle": 0, + "content": "[36] Zexiang Liu, Dong Li, Kaiyue Lu, Zhen Qin, Weixuan Sun, Jiacheng Xu, and Yiran Zhong. Neural architecture search on efficient transformers and beyond. arXiv preprint arXiv:2207.13955, 2022. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.255, + 0.469, + 0.307 + ], + "angle": 0, + "content": "[37] Qian Lou, Yilin Shen, Hongxia Jin, and Lei Jiang. Safenet: A secure, accurate and fast neural network inference. In International Conference on Learning Representations, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.308, + 0.469, + 0.376 + ], + "angle": 0, + "content": "[38] Jiachen Lu, Jinghan Yao, Junge Zhang, Xiatian Zhu, Hang Xu, Weiguo Gao, Chunjing Xu, Tao Xiang, and Li Zhang. Soft: Softmax-free transformer with linear complexity. Advances in Neural Information Processing Systems, 34:21297-21309, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.377, + 0.469, + 0.471 + ], + "angle": 0, + "content": "[39] Junming Ma, Yancheng Zheng, Jun Feng, Derun Zhao, Haoqi Wu, Wenjing Fang, Jin Tan, Chaofan Yu, Benyu Zhang, and Lei Wang. SecretFlow-SPU: A performant and User-Friendly framework for Privacy-Preserving machine learning. In 2023 USENIX Annual Technical Conference (USENIX ATC 23), pages 17–33, Boston, MA, July 2023. USENIX Association. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.472, + 0.469, + 0.527 + ], + "angle": 0, + "content": "[40] Andre Martins and Ramon Astudillo. From softmax to sparsemax: A sparse model of attention and multi-label classification. In International conference on machine learning, pages 1614-1623. PMLR, 2016. 4, 14" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.527, + 0.469, + 0.568 + ], + "angle": 0, + "content": "[41] Paul Michel, Omer Levy, and Graham Neubig. Are sixteen heads really better than one? Advances in neural information processing systems, 32, 2019. 5, 15" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.568, + 0.469, + 0.621 + ], + "angle": 0, + "content": "[42] Pratyush Mishra, Ryan Lehmkuhl, Akshayaram Srinivasan, Wenting Zheng, and Raluca Ada Popa. Delphi: A cryptographic inference service for neural networks. In USENIX Security Symposium, pages 2505-2522, 2020. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.621, + 0.469, + 0.675 + ], + "angle": 0, + "content": "[43] Payman Mohassel and Peter Rindal. Aby3: A mixed protocol framework for machine learning. In Proceedings of the 2018 ACM SIGSAC conference on computer and communications security, pages 35-52, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.675, + 0.469, + 0.728 + ], + "angle": 0, + "content": "[44] Payman Mohassel and Yupeng Zhang. Securel: A system for scalable privacy-preserving machine learning. In IEEE symposium on security and privacy (S&P), pages 19-38. IEEE, 2017. 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.729, + 0.469, + 0.768 + ], + "angle": 0, + "content": "[45] Moni Naor and Benny Pinkas. Computationally secure oblivious transfer. Journal of Cryptology, 18(1):1-35, 2005. 14" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.769, + 0.469, + 0.823 + ], + "angle": 0, + "content": "[46] Zizheng Pan, Bohan Zhuang, Haoyu He, Jing Liu, and Jianfei Cai. Less is more: Pay less attention in vision transformers. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 2035-2043, 2022. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.823, + 0.469, + 0.892 + ], + "angle": 0, + "content": "[47] Hongwu Peng, Shanglin Zhou, Yukui Luo, Shijin Duan, Nuo Xu, Ran Ran, Shaoyi Huang, Chenghong Wang, Tong Geng, Ang Li, et al. Polympcnet: Towards relu-free neural architecture search in two-party computation based private inference. arXiv preprint arXiv:2209.09424, 2022. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.892 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.161 + ], + "angle": 0, + "content": "[48] Hongwu Peng, Shanglin Zhou, Yukui Luo, Nuo Xu, Shijin Duan, Ran Ran, Jiahui Zhao, Shaoyi Huang, Xi Xie, Chenghong Wang, et al. Rrnet: Towards relu-reduced neural network for two-party computation based private inference. arXiv preprint arXiv:2302.02292, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.161, + 0.892, + 0.242 + ], + "angle": 0, + "content": "[49] Zhen Qin, Weixuan Sun, Hui Deng, Dongxu Li, Yunshen Wei, Baohong Lv, Junjie Yan, Lingpeng Kong, and Yiran Zhong. cosformer: Rethinking softmax in attention. In The Tenth International Conference on Learning Representations, ICLR 2022, Virtual Event, April 25-29, 2022. OpenReview.net, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.243, + 0.892, + 0.311 + ], + "angle": 0, + "content": "[50] Deevashwer Rathee, Mayank Rathee, Rahul Kranti Kiran Goli, Divya Gupta, Rahul Sharma, Nishanth Chandran, and Aseem Rastogi. Sirnn: A math library for secure rn n inference. In 2021 IEEE Symposium on Security and Privacy (SP), pages 1003-1020. IEEE, 2021. 14" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.311, + 0.892, + 0.379 + ], + "angle": 0, + "content": "[51] Deevashwer Rathee, Mayank Rathee, Nishant Kumar, Nishanth Chandran, Divya Gupta, Aseem Rastogi, and Rahul Sharma. Cryptflow2: Practical 2-party secure inference. In ACM SIGSAC Conference on Computer and Communications Security (CCS), pages 325-342, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.379, + 0.892, + 0.405 + ], + "angle": 0, + "content": "[52] Adi Shamir. How to share a secret. Communications of the ACM, 22(11):612-613, 1979. 13" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.406, + 0.892, + 0.445 + ], + "angle": 0, + "content": "[53] Jeong-geun Song. Ufo-vit: High performance linear vision transformer without softmax. arXiv preprint arXiv:2109.14382, 2021. 2, 4, 14" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.446, + 0.892, + 0.528 + ], + "angle": 0, + "content": "[54] Xiu Su, Shan You, Jiyang Xie, Mingkai Zheng, Fei Wang, Chen Qian, Changshui Zhang, Xiaogang Wang, and Chang Xu. Vitas: Vision transformer architecture search. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXI, pages 139-157. Springer, 2022. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.528, + 0.892, + 0.595 + ], + "angle": 0, + "content": "[55] Mingxing Tan, Bo Chen, Ruoming Pang, Vijay Vasudevan, Mark Sandler, Andrew Howard, and Quoc V Le. Mnasnet: Platform-aware neural architecture search for mobile. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2820-2828, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.596, + 0.892, + 0.718 + ], + "angle": 0, + "content": "[56] Elena Voita, David Talbot, Fedor Moiseev, Rico Sennrich, and Ivan Titov. Analyzing multi-head self-attention: Specialized heads do the heavy lifting, the rest can be pruned. In Anna Korhonen, David R. Traum, and Lluis Marquez, editors, Proceedings of the 57th Conference of the Association for Computational Linguistics, ACL 2019, Florence, Italy, July 28- August 2, 2019, Volume 1: Long Papers, pages 5797-5808. Association for Computational Linguistics, 2019. 5, 15" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.719, + 0.892, + 0.786 + ], + "angle": 0, + "content": "[57] Kuan Wang, Zhijian Liu, Yujun Lin, Ji Lin, and Song Han. Haq: Hardware-aware automated quantization with mixed precision. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 8612-8620, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.788, + 0.892, + 0.827 + ], + "angle": 0, + "content": "[58] Sinong Wang, Belinda Z Li, Madian Khabsa, Han Fang, and Hao Ma. Linformer: Self-attention with linear complexity. arXiv preprint arXiv:2006.04768, 2020. 2, 4, 7, 14" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.828, + 0.892, + 0.88 + ], + "angle": 0, + "content": "[59] Xiaolong Wang, Ross Girshick, Abhinav Gupta, and Kaiming He. Non-local neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 7794-7803, 2018. 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.881, + 0.892, + 0.895 + ], + "angle": 0, + "content": "[60] Yongqin Wang, G Edward Suh, Wenjie Xiong, Benjamin" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.895 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "5062" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.161 + ], + "angle": 0, + "content": "Lefaudeau, Brian Knott, Murali Annavaram, and Hsien-Hsin S Lee. Characterization of mpc-based private inference for transformer-based models. In 2022 IEEE International Symposium on Performance Analysis of Systems and Software (ISPASS), pages 187-197. IEEE, 2022. 1, 7, 13, 14" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.161, + 0.47, + 0.243 + ], + "angle": 0, + "content": "[61] Bichen Wu, Xiaoliang Dai, Peizhao Zhang, Yanghan Wang, Fei Sun, Yiming Wu, Yuandong Tian, Peter Vajda, Yangqing Jia, and Kurt Keutzer. Fbnet: Hardware-aware efficient convnet design via differentiable neural architecture search. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10734-10742, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.243, + 0.471, + 0.339 + ], + "angle": 0, + "content": "[62] Mengzhou Xia, Zexuan Zhong, and Danqi Chen. Structured pruning learns compact and accurate models. In Smaranda Muresan, Preslav Nakov, and Aline Villavicencio, editors, Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), ACL 2022, Dublin, Ireland, May 22-27, 2022, pages 1513-1528. Association for Computational Linguistics, 2022. 15" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.339, + 0.471, + 0.379 + ], + "angle": 0, + "content": "[63] Andrew C Yao. Protocols for secure computations. In 23rd annual symposium on foundations of computer science (sfcs 1982), pages 160-164. IEEE, 1982. 14" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.379, + 0.471, + 0.448 + ], + "angle": 0, + "content": "[64] Pengchuan Zhang, Xiyang Dai, Jianwei Yang, Bin Xiao, Lu Yuan, Lei Zhang, and Jianfeng Gao. Multi-scale vision longformer: A new vision transformer for high-resolution image encoding. In Proceedings of the IEEE/CVF international conference on computer vision, pages 2998-3008, 2021. 1" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.448 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "5063" + } + ] +] \ No newline at end of file diff --git a/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/844d9362-4725-44da-8709-8687e3c64eb2_origin.pdf b/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/844d9362-4725-44da-8709-8687e3c64eb2_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..6721725a4c403660c3c8a92030aeba09fdd6fc08 --- /dev/null +++ b/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/844d9362-4725-44da-8709-8687e3c64eb2_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:0e0a881f55290420c383a5e1715e4b8faea52e2c0a1deee7edc762cee03db764 +size 4733209 diff --git a/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/full.md b/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/full.md new file mode 100644 index 0000000000000000000000000000000000000000..ba43c894de8a7134c4846fa44ff7509c6cd9765a --- /dev/null +++ b/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/full.md @@ -0,0 +1,372 @@ +# MPCViT: Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention + +Wenxuan Zeng $^{1}$ Meng Li $^{1*}$ Wenjie Xiong $^{2}$ Tong Tong $^{1}$ Wen-jie Lu $^{3}$ Jin Tan $^{3}$ Runsheng Wang $^{1}$ Ru Huang $^{1}$ $^{1}$ Peking University $^{2}$ Virginia Tech $^{3}$ Ant Group + +{zwx.andy,tongtong}@stu.pku.edu.cn, {meng.li,wrs,ruhuang}@pku.edu.cn, wenjiex@vt.edu, {juhou.lwj,tanjin.tj}@antgroup.com + +# Abstract + +Secure multi-party computation (MPC) enables computation directly on encrypted data and protects both data and model privacy in deep learning inference. However, existing neural network architectures, including Vision Transformers (ViTs), are not designed or optimized for MPC and incur significant latency overhead. We observe Softmax accounts for the major latency bottleneck due to a high communication complexity, but can be selectively replaced or linearized without compromising the model accuracy. Hence, in this paper, we propose an MPC-friendly ViT, dubbed MPCViT, to enable accurate yet efficient ViT inference in MPC. Based on a systematic latency and accuracy evaluation of the Softmax attention and other attention variants, we propose a heterogeneous attention optimization space. We also develop a simple yet effective MPC-aware neural architecture search algorithm for fast Pareto optimization. To further boost the inference efficiency, we propose MPCViT $^+$ , to jointly optimize the Softmax attention and other network components, including GeLU, matrix multiplication, etc. With extensive experiments, we demonstrate that MPCViT achieves $1.9\%$ , $1.3\%$ and $3.6\%$ higher accuracy with $6.2\times$ , $2.9\times$ and $1.9\times$ latency reduction compared with baseline ViT, MPCFormer and THE-X on the Tiny-ImageNet dataset, respectively. MPCViT $^+$ further achieves a better Pareto front compared with MPCViT. The code and models for evaluation are available at https://github.com/PKU-SEC-Lab/mpcvit. + +# 1. Introduction + +As machine learning models are handling increasingly sensitive data and tasks, privacy has become one of the major concerns during the model deployment. Secure multi-party computation (MPC) [14] can protect the privacy of + +![](images/51f3964077c43d86aff9aa56b9faab1fc634fd7c6f3e242b9d1b85dac77fb754.jpg) +Figure 1. The latency breakdown of a Transformer block w.r.t (a) # heads and (b) # tokens; and (c) the relative error of Softmax and ReLU Softmax with different input variances. + +![](images/8924f7f556a5fe338742235b27bb24aa1a5e9cf97969c134f67c403abe275b0b.jpg) + +![](images/12b0bc74a33f1db51d5dc8d51a6897463daac312638274cf9415baa3cc7c74fd.jpg) + +both data and deep neural network (DNN) models and has gained a lot of attention in recent years [42, 51, 60]. + +However, existing DNN architectures, especially the recently proposed Vision Transformers (ViTs) [2, 11, 64], are not designed or optimized for MPC (the high-level private ViT inference framework in MPC is shown in Figure 2 and Appendix A.1). Although ViTs have achieved superior performance for various vision tasks [2, 15, 16, 64], they face several realistic limitations when directly deployed in MPC: 1) communication overhead: in contrast to regular inference on plaintext, operations like Softmax, GeLU, max, etc, require intensive communication in MPC, which usually dominates the total inference latency [42, 60]. For example, Softmax is usually very lightweight in plaintext inference. However, as shown in Figure 1(a) and Figure 1(b), it accounts for the majority of the Transformer inference latency due to the high communication complexity; 2) approximation error: operations like exponential, tanh, reciprocal, etc, cannot be computed directly and require iterative approximation, limiting the computation accuracy. For instance, as shown in Figure 1(c), the relative error of Softmax significantly increases when the input variance is large due to its narrow dynamic range [60]. In contrast, replacing exponential in Softmax with ReLU reduces the relative error drastically (denoted as ReLU Softmax in §2.2). + +Numerous efficient Transformer variants have been pro + +![](images/34002c189cff84ca15fb9c50cf7a5479470d1d7120442c1472bf183e373513f0.jpg) +Figure 2. An overall illustration of private Vision Transformer inference in the MPC framework. + +posed in recent years [5, 29, 49, 58]. Linear Transformers, including Linformer [58], cosFormer [49], Reformer [29], etc, reduce the quadratic computation complexity of the attentions and significantly accelerate model inference for long sequences. However, these Transformer optimizations have primarily focused on reducing the network computation. Hence, they either retain complex non-linear functions or still require iterative approximation, both resulting in intensive communication overhead in MPC. Recently, MPC-Former [33] and THE-X [6] are proposed to improve the inference efficiency of BERT [28] in MPC. MPCFormer simplifies Softmax by replacing exponential with a more MPC-friendly quadratic operation while THE-X approximates Softmax with a small estimation network. However, their attention variants is not flexible and can still be too expensive for certain latency constraints. Moreover, the network-level optimization suffers from a large accuracy degradation when directly applied to vision tasks. + +In this work, we first breakdown Softmax into more atomic operations and analyze their impact on the inference accuracy and efficiency, based on which we propose and compare a set of attention variants comprehensively. The comparison enables us to find MPC-friendly attention variants, which are either highly accurate or highly efficient. We further observe not all attentions are equally important within a ViT. Based on these observations, we propose the first MPC-friendly ViT architecture, dubbed MPCViT. MPCViT features a heterogeneous attention design space to explore the trade-off between accuracy and efficiency, and an MPC-aware differentiable neural architecture search (NAS) algorithm for effective Pareto optimization. Our contributions can be summarized as follows: + +- We breakdown Softmax and reveal the impact of atomic operations on the inference accuracy and efficiency, based on which a heterogeneous attention design space is proposed. +- We propose an effective MPC-aware differentiable NAS algorithm to explore the attention design space based on real latency measurements instead of proxies. To the best of our knowledge, we make the first + +attempt to introduce the MPC-aware NAS to optimize ViT inference in MPC. + +- Our MPC-friendly ViT model family, MPCViT, outperforms prior-art models in MPC in terms of both accuracy and efficiency. MPCViT achieves $1.9\%$ and $1.3\%$ higher accuracy with $6.2\times$ and $2.9\times$ latency reduction compared with baseline ViT and MPCFormer on Tiny-ImageNet dataset, respectively. +- We further extend MPCViT to optimize other Transformer components simultaneously with Softmax, named $\mathrm{MPCViT}^+$ , achieving an even better Pareto front compared with MPCViT. + +# 2. Preliminaries and Related Works + +# 2.1. ViT and Efficient Attention + +ViT architecture. ViT [11] has demonstrated a great potential to capture the long-range visual dependencies. It takes image patches as input and is composed of an input projection layer, a stack of Transformer layers, and a task-specific multi-layer perceptron (MLP) head. Each layer consists of a multi-head attention (MHA) layer and an MLP block. The core computation is the Softmax attention: + +$$ +\operatorname {A t t e n t i o n} (Q, K, V) = \operatorname {S o f t m a x} \left(\frac {Q K ^ {T}}{\sqrt {d _ {k}}}\right) V, +$$ + +where $Q, K, V$ are queries, keys and values, respectively. $d_{k}$ denotes the embedding dimension of each key, and Softmax normalizes the attention map. The detailed explanation of ViT architecture is shown in Figure 2 and Appendix A.2. + +Linear attention. Linear attention has been widely studied in previous works [5, 29, 38, 49]. These works aim at reducing the quadratic increase of compute and memory by leveraging special kernel functions. Different kernel functions have been proposed in existing works [4, 49, 53, 58]. UFO-ViT [53] proposes to use $\ell 2$ -Norm as the kernel function while CosFormer [49] leverages the cosine distance kernel. Linformer [58] approximates self-attention by a low-rank matrix. Hydra Attention [4] proposes to use as many heads as possible to further reduce the computation + +Table 1. Comparison among existing network optimizations for the efficient private inference. + +
MethodModelTechniqueOptimized ComponentGranularityLinear Fusion
Delphi [42]CNNReLU-aware NASReLULayerX
DeepReDuce [25]CNNManually removalReLULayerX
CryptoNAS [13]CNNReLU-aware NASReLULayerX
SNL [8]CNNReLU-aware NASReLUChannel, pixelX
Sphinx [7]CNNBlock-level NASReLUBlockX
SENet [31]CNNSensitivity-aware alloc.ReLULayer, pixelX
RRNet [48]CNNHardware-aware NASReLULayerX
DeepReShape [26]CNNReLU-equalizationReLUStageX
SAFENet [31]CNNMixed-precision poly. approx.ReLUChannelX
THE-X [6]BERTPolynomial approx.GeLU, Softmax, LayerNormNetworkX
MPCFormer [33]BERTPolynomial approx.Softmax, GeLUNetworkX
MPCViT (ours)ViTMPC-aware NASSoftmaxLayer, head, rowX
Heterogeneous attention
MPC-aware NAS
MPCViT+ (ours)ViTHeterogeneous attentionSoftmax, GeLU, MatMulLayer, head, row, token✓
GeLU linearization
Linear fusion
+ +complexity of the linear attention. However, these works primarily focus on reducing the network computation rather than the communication overhead and are not beneficial for ViT inference in MPC. + +Non-local neural networks and Scaling attention. [59] presents a generic non-local operation to capture long-range dependencies. The formulation is defined as $\frac{1}{\mathcal{C}(x)}\sum_{\forall j}f(x_i,x_j)g(x_j)$ , where $x$ denotes the input feature map and $f(\cdot)$ is a similarity function, e.g., cosine or Euclidean distance. $g(\cdot)$ computes a certain input representation, and $\mathcal{C}(x)$ is a normalization factor. By setting $f(\cdot)$ as the dot-product similarity and $\mathcal{C}(x) = n$ , where $n$ is the sequence length, we get an attention variant, named Scaling Attention (ScaleAttn). ScaleAttn is an extremely simple attention and only involves linear operations like multiplication and addition. ScaleAttn can be further reparameterized to accelerate computation1 as below: + +$$ +\mathrm {S c a l e A t t n} (Q, K, V) = \frac {1}{n} (Q K ^ {T}) V = \frac {Q}{\sqrt {n}} (\frac {K ^ {T}}{\sqrt {n}} V). +$$ + +# 2.2. Multi-Party Computation + +MPC [14] is a cryptographic technique that offers a promising solution to protect the privacy of both data and model during deep learning inference. Appendix B depicts the cryptographic primitives for MPC, including Secret Sharing, Oblivious Transfer and Garble Circuit. [14] proposes an efficient MPC protocol for addition and multiplication. [44] proposes efficient two-party computation protocols for various arithmetic operations and approximations for non-linear functions in DNN. For example, [44] + +approximates Softmax with ReLU Softmax, i.e., + +$$ +\operatorname {R e L U S o f t m a x} (x) = \frac {\operatorname {R e L U} (x _ {i})}{\sum_ {i} \operatorname {R e L U} (x _ {i}) + \epsilon}, +$$ + +where $\epsilon$ is a very small value to avoid the zero denominator. ABY3 [43] is proposed to enable efficient conversion between different secret sharing schemes in three-party computation. Delphi [42] develops a hybrid MPC protocol and optimizes the network to explore the performance-accuracy trade-off. Iron [18] proposes a set of protocols to reduce the communication overhead of matrix-matrix multiplications (MatMuls), LayerNorm, etc for Transformer-based models. + +Although MPC protocols have been improved significantly in recent years, DNN inference in MPC still suffers from intensive communication and latency overhead compared to the plaintext inference. To reduce the latency, different algorithms have been proposed to optimize convolutional NNs (CNNs) with a focus on ReLU. We compare the important characteristics of our methods with existing related work in Table 1. SNL [8] and DeepReduce [25] propose to remove ReLUs and linearize a subset of neurons selectively. SAFENet [37], Delphi [42], RRNet [48] and PolyMPCNet [47] replace ReLUs with polynomial functions that are more MPC-friendly via NAS for CNNs. Sphynx [7] further develops an MPC-friendly architecture search space for CNNs and leverages NAS to optimize the accuracy given different latency constraints. However, these works mainly focus on the ReLU counts in CNNs, and accelerating ViTs with latency consideration is still a challenge. MPCFormer [33] and THE-X [6] recently propose to replace Softmax with more MPC-friendly operations for BERT, but the network-level method incurs limited latency reduction and a large accuracy degradation. As shown in Table 1, our work proposes an MPC-aware NAS to explore a fined-grained heterogeneous attention optimization space, and further presents a GeLU linearization + +Table 2. Top-1 accuracy and latency comparison of different attention variants on CIFAR-10. The rows in grey are attention variants with the lowest latency and the highest accuracy, respectively. We also show the properties and remaining operations of each variant. + +
Attention VariantMonotonicityNon-negativityNormalizationExponentialMaxReciprocalAcc. (%)Lat. (s)
Softmax Attention [11]✓✓✓✓✓✓92.696.82
Linformer Attention [58]✓✓✓✓✓✓90.855.44
ReLU Attention✓✓✗✗✓✗failfail
ReLU6 Attention✓✓✗✗✓✗90.503.02
Sparsemax Attention [40]✓✓✗✗✓✗91.233.23
XNorm Attention [53]✓✗✗✗✗✓91.2413.25
Square Attention✗✓✗✗✗✗91.270.72
2Quad Attention [33]✗✓✓✗✗✓91.864.22
Scaling Attention (ScaleAttn) [59]✓✗✗✗✗✗91.520.66
ReLU Softmax Attention (RSAAttn) [44]✓✓✓✗✓✓92.315.32
+ +![](images/47634366d0c7d64767a1c148d641e59259a3bb4fff777524082ae8e284452b38.jpg) +Figure 3. (a) Latency breakdown of a 4-head ViT with 256 hidden dimension and 65 tokens on CIFAR-10 dataset; (b) latency breakdown of Softmax. Both (a) and (b) consist of SEMI-2K (outside) and Cheetah (inside) protocols. + +technique to reduce the latency of MLP. + +# 3. Motivating Inspiration of MPCViT + +In this section, we breakdown Softmax for accuracy and efficiency evaluation and compare two ways of building MPC-friendly ViTs. The analysis serves as our motivation of proposing MPCViT, which features heterogeneous attention and NAS-based Pareto optimization. + +Motivation 1: ViT latency bottleneck in MPC. In Figure 1, we profile the latency of a Transformer block with different number of heads and tokens. We now further dive into Softmax and evaluate its latency breakdown. We profile a 4-head ViT with 65 tokens and 256 hidden dimension assuming the WAN setting as defined in §5.1. We consider two widely used protocols, including SEMI-2K [9] and Cheetah [22]. From both Figure 1 and Figure 3, we make the following observations: 1) Softmax is the major latency bottleneck in most cases. The latency of GeLU and MatMuls also becomes non-negligible when the number of heads or tokens is small; 2) Softmax mainly involves three operations, including exponential, reciprocal and max. All of the operations are important for the latency overhead. Therefore, we are motivated to get rid of these expensive operations as many as possible, and we propose to first focus on optimizing the Softmax and only consider GeLU and MatMul when the number of heads or tokens is small. + +Motivation 2: comparison of different attention variants. To reduce the latency of Softmax in the attention module, there are two different ways, i.e., 1) reducing the dimension of $QK^T$ such as Linformer [58], which approximates $QK^T$ with a low rank matrix; and 2) simplifying Softmax by replacing exponential, reciprocal or max with other operations. For the second method, while the possible activation variants can be abundant, we observe the following three important properties of Softmax, which helps us to select promising candidates: monotonicity, non-negativity, and normalized sum to 1. The first two properties are related to the exponential while the last one is achieved with reciprocal. We propose and evaluate the following variants, including ReLU, ReLU6, Sparsemax [40], XNorm [53], Square, Scaling [59], 2Quard [33], Linformer [58] and ReLU Softmax [44]. We define the attention with ReLU Softmax as RSAttn for short. The formulation of these attention variants is described in Appendix C. + +To compare these attention variants, we train each model for 300 epochs on CIFAR-10 and compare the latency, accuracy, remaining operations, and how they satisfy the properties of Softmax in Table 2. We make the following observations: 1) Attention with more expensive operations can be more inefficient. For instance, 2Quad has an extra reciprocal compared with Square such that 2Quad suffers from a higher latency; 2) Linformer suffers from a high accuracy degradation ( $\sim 1.8\%$ compared with Softmax attention) as it significantly reduces the matrix dimensions such that the model learning capability is degraded, and the computation reduction of this optimization cannot benefit latency reduction a lot. Hence, the first method is not preferred; 3) ReLU Softmax and 2Quad achieve higher accuracy among other variants and we hypothesize this is because they both normalize the sum to 1, which is realized with reciprocal and also leads to relatively higher latency. ReLU Softmax is more preferred over Softmax and 2Quad due to its small approximation error and small accuracy degradation; 4) Scaling is equivalent to directly removing the Softmax. Although it is the fastest, directly linearizing all the Softmax leads to a large accuracy degradation; 5) it is interesting to notice that although XNorm attention has linear com + +putation, it incurs the highest latency because computing $\ell 2$ -norm involves both reciprocal and square root, both of which are expensive in MPC. + +Motivation 3: Not all attentions are equally important. As observed in [5, 36, 41, 46, 54, 56], not all attentions are equally important and different layer prefers different attention type. For instance, [46] identifies the minor contribution of the early attention layers in recent ViTs, while [34] demonstrates the second head shows higher importance than other heads. Thus, the importance of attentions among different layers or even the attentions within the same layer can be different. It indicates we can safely replace the expensive Softmax or ReLU Softmax with the cheaper Scaling without compromising the network accuracy. + +Remark The analysis above provides us with the following intuitions when designing an MPC-friendly ViT: + +1) ReLU Softmax is more preferred over Softmax and more MPC-friendly, and Scaling has the highest inference efficiency; +2) by selectively replacing the ReLU Softmax with the cheaper Scaling, it is possible to reduce the inference latency without compromising the inference accuracy; +3) when the latency of GeLU and Softmax are comparable, we have an opportunity to further simplify GeLU along with Softmax. + +# 4. The Proposed MPCViT Algorithm + +In this section, we introduce MPCViT, which for the first time optimizes the ViT architecture with NAS-based algorithm for a fast private inference in MPC. + +# 4.1. Overview of Optimization Flow + +Based on the motivations described above, we now describe our MPC-aware ViT optimization flow as shown in Figure 4. We propose to replace the Softmax with the accurate yet MPC-friendly ReLU Softmax in the ViT first and then, linearize the relatively "unimportant" ReLU Softmax with efficient Scaling. To find the "unimportant" ReLU Softmax, we first design a heterogeneous search space that includes both ReLU Softmax and Scaling attentions. Architecture parameters are defined to measure the importance of ReLU Softmax and enable the selection between the two attention variants with different structure granularities (§4.2). Then, we propose an MPC-aware differentiable NAS algorithm to learn the architecture parameters and model parameters simultaneously. We select between the attention variants based on the architecture parameters and the latency constraints (§4.3). In the last step, we retrain the ViT with heterogeneous attentions from scratch. We leverage knowledge distillation (KD) to improve the accuracy of the searched networks (§4.4). Appendix D depicts the complete algorithm flow of MPCViT. + +![](images/698fe7e2af04aca536d4b0f02fcfcdc169a001e5e04c3922111a38767c9a25e7.jpg) +Figure 4. Overview of our proposed MPCViT pipeline. + +# 4.2. Heterogeneous Attention Search Space + +Our heterogeneous search space combines two candidate attention variants, i.e., MPC-efficient ScaleAttn and high-accuracy RSAAttn and has the following three different structural granularities as shown in Figure 5: + +- Layer-wise search space is coarse-grained, with each layer using either ScaleAttn or RSAattn. The total number of possible architectures in the search space can be limited, especially for shallow ViT models. +- Head-wise search space selects ScaleAttn or RSAAttn for each attention head of each layer. +- Row-wise search space (i.e., token-wise) is the most fine-grained and mixes the two attention variants along each row of the attention map. + +Though the search spaces have different granularities, they share very similar NAS formulation. In the rest of the explanation, we will use the head-wise search space as an example to explain our algorithm. + +# 4.3. MPC-Aware Differentiable NAS + +Many research efforts have been made to NAS including reinforcement learning method (RL) [17, 24, 57], however, RL-based NAS requires significant overhead during searching. Recent years, [10, 27, 55, 61] explore hardware-aware NAS algorithms to make model fit the rigorous hardware requirement. For private ViT inference, we also need a NAS algorithm that takes MPC conditions into consideration. + +Given the heterogeneous attention search space, we now introduce our simple yet effective MPC-aware differentiable NAS algorithm. + +Search formulation. Inspired by [5], we introduce an architecture parameter $\alpha$ ( $0 \leq \alpha \leq 1$ ) for each head, which is an auxiliary learnable variable that helps to choose between RSAAtt and ScaleAttn. Then, each head implements the computation below: + +$$ +\alpha \cdot \operatorname {R e L U S o f t m a x} \left(\frac {Q K ^ {T}}{\sqrt {d _ {k}}}\right) V + (1 - \alpha) \cdot \frac {\operatorname {S c a l e A t t n} (Q , K , V)}{\sqrt {d _ {k}}}. +$$ + +![](images/ffe906ef0c4c3f9cf186366397d0781739333ecc01c993cf203d5dfc4821633a.jpg) +Figure 5. An illustration of our proposed search space with different structure granularities: (a) layer-wise search space with the size of $2^{\# \text{layers}}$ ; (b) head-wise search space with the size of $2^{\# \text{layers} \times \# \text{heads}}$ and; (c) row-wise search space with the size of $2^{\# \text{layers} \times \# \text{heads} \times \# \text{tokens}}$ . The blocks in blue represent RSAAttn and the blocks in grey represent ScaleAttn. + +Note that we also add $\frac{1}{\sqrt{d_k}}$ for ScaleAttn to make the search process more stable and robust. + +Search objective function. We aim at training ViTs with high accuracy but as few RSAattn as possible. We introduce $\ell 1$ -penalty into the objective function and formulate the NAS as a one-level optimization problem. To take MPC overhead into consideration, we incorporate realistic inference latency constraints into objective function to construct the MPC-aware NAS algorithm as + +$$ +\mathrm {C o s t} (\alpha_ {i j}) = \alpha_ {i j} \cdot \mathrm {L a t (A T T N} _ {i j}), +$$ + +$$ +\min _ {\theta , \alpha} \ell (f _ {\theta , \alpha} (x), y) + \lambda \cdot (\sum_ {i = 1} ^ {L} \sum_ {j = 1} ^ {N} \| \operatorname {C o s t} (\alpha_ {i j}) \| _ {1}), +$$ + +where $x$ and $y$ are the input-label pairs, $\ell(\cdot)$ is the loss function, $\lambda$ is a hyper-parameter to control the weight of inference overhead, $N$ is the number of heads in one layer, and $L$ is the number of layers. $\| \cdot \|_1$ means $\ell 1$ -norm, and $\mathrm{ATTN}_{ij}$ means the candidate attention of $i$ -th layer and $j$ -th head. We initialize $\alpha$ for each head to 1.0 and jointly optimize the network parameter $\theta$ and architecture parameter $\alpha$ during searching. Note that our differentiable algorithm computes the gradients of $\alpha$ for all the attention heads across different layers in ViT simultaneously. + +Architecture parameter binarization. After the network searching, we obtain $\alpha$ for each attention head in all layers. To select either RSAattn or ScaleAttn for each head, we binarize $\alpha$ based on the following rule: we use the top- $k$ rule according to the ratio of RSAattn budgeet $\mu$ , which is defined as $\# \text{RSAattn} / \# \text{Heads}$ . Specifically, we first find the $\mu L N$ -th largest $\alpha$ , denoted as $\alpha^{*}$ , and then we binarize $\alpha$ for each attention head following $\mathbb{1}(\alpha \geq \alpha^{*})$ . Our proposed search method does not need to train candidate networks, but only needs to train once and then select, which accelerates our search process. Now, we obtain a heterogeneous ViT, and by changing $\mu$ , we can obtain a family of + +![](images/af21e0dc47712bcf343889eb7b92c595f0a6d63eb1b0d8a92516e29847a27dc0.jpg) +Figure 6. MPCViT+: The optimization of our proposed GeLU linearization and linear fusion for the MLP block. + +ViTs with different accuracy and efficiency trade-off. + +# 4.4. Train the Searched ViT for Better Performance + +After binarization, RSAattn with a small $\alpha$ are replaced with ScaleAttn. We find that directly training a heterogeneous ViT results in an accuracy drop. So, how to effectively train the heterogeneous ViT and restore the model accuracy is an important question for us. + +Token-wise feature-based KD. KD [21] is a powerful tool for a student network to learn from a teacher network, which is usually larger and more complex with a higher learning capacity. To improve the accuracy of MPCViT, we leverage token-wise feature-based self-distillation along with a logits-based KD, which uses the baseline ViT as the teacher network while other larger networks can be easily plugged in and used in our framework. For the feature-based KD, we take the output features of the last ViT layer from both the student and the teacher networks and compute the $\ell 2$ -distance, denoted as $\mathcal{L}_{\text {feature }}$ . We also use KL-divergence loss $\mathcal{L}_{KL}$ for the logits-based KD, denoted as $\mathcal{L}_{\text {logits }}$ . Combining distillation loss with the task-specific cross-entropy (CE) loss $\mathcal{L}_{CE}$ , we obtain the final training objective under a distillation temperature $\mathcal{T}$ as follows: + +$$ +\begin{array}{l} \mathcal {L} _ {\text {t r a i n}} = \chi \mathcal {L} _ {C E} + \beta \mathcal {L} _ {\text {l o g i t s}} + \gamma \mathcal {L} _ {\text {f e a t u r e}} \\ = \chi \mathcal {L} _ {C E} + \beta \mathcal {L} _ {K L} (\sigma (\frac {z _ {s}}{\mathcal {T}}), \sigma (\frac {z _ {t}}{\mathcal {T}})) + \gamma \| z _ {s} - z _ {t} \| _ {2}, \\ \end{array} +$$ + +where $\chi, \beta$ and $\gamma$ are training hyper-parameters to balance different loss functions in the training objective, $z_{s}$ and $z_{t}$ are feature maps from student and teacher, and $\sigma$ is Softmax. This self-distillation requires no extra model and only introduces negligible training cost, and has no influence on inference latency or communication overhead in MPC. + +# 4.5. MPCViT+: Support for GeLU Linearization + +The above design of MPCViT leverages NAS algorithm to build the efficient yet effective attention mechanism. Besides attention, in MLP blocks, non-linear GeLU also impacts the communication cost in some protocols, e.g., Cheetah when the number of heads or tokens is small. And two linear layers near GeLU are also costly because + +the inverted-bottleneck structure of MLP leads to high-dimensional MatMul, which is shown in Figure 1 and Figure 3(a). To further improve the efficiency of ViTs, we propose an extended version called MPCViT+. Specifically, MPCViT+ searches and removes relatively "unimportant" GeLUs. Given architecture parameter $\beta$ for GeLU, the NAS algorithm is similar to the attention optimization: + +$$ +(\beta \cdot \operatorname {G e L U} (x) + (1 - \beta) \cdot x) \cdot \mathscr {W}. +$$ + +The architecture parameters $\alpha$ and $\beta$ are jointly learnt during the search, thus the NAS loss is defined along with the classification loss $\min_{\theta ,\alpha ,\beta}\ell (f_{\theta ,\alpha ,\beta}(x),y)$ .. + +$$ +\operatorname {C o s t} \left(\beta_ {i j}\right) = \beta_ {i j} \cdot \operatorname {L a t} \left(\operatorname {A c t} _ {i j}\right), +$$ + +$$ +\lambda \cdot (\sum_ {i = 1} ^ {L} \sum_ {j = 1} ^ {N} \| \operatorname {C o s t} \left(\alpha_ {i j}\right) \| _ {1}) + \eta \cdot (\sum_ {i = 1} ^ {L} \sum_ {j = 1} ^ {T} \| \operatorname {C o s t} \left(\beta_ {i j}\right) \| _ {1}), +$$ + +here, we take token-wise linearization as an example, and $\mathrm{Lat}(\mathrm{Act}_{\mathrm{ij}})$ denotes the latency of either GeLU or identity of $i$ -th layer and $j$ -th token, $T$ denotes the number of tokens in each layer. We can consider the balance between $\lambda$ and $\eta$ through the private inference latency: $\frac{\lambda}{\eta} = \frac{\mathrm{Lat}(\mathrm{ATTN})}{\mathrm{Lat}(\mathrm{GELU})}$ . + +Fuse two linear layers together. After GeLU linearization, we observe an opportunity for further latency reduction. As shown in Figure 6, we fuse the linear layer before and after GeLU of a certain token, which reduces the communication associated with the MLP. Denote the input of a MLP block of $i$ -th layer as $X^{(i)} \in \mathbb{R}^{B \times H \times W \times C}$ , the linear layers as $\mathcal{W}_1^{(i)} \in \mathbb{R}^{C \times K}$ and $\mathcal{W}_2^{(i)} \in \mathbb{R}^{K \times C}$ , the output of MLP as $X^{(i+1)} \in \mathbb{R}^{B \times H \times W \times C}$ . The input dimension of GeLU is $B \times H \times W \times K$ , and $C, K$ are channel numbers of linear layers. Note that we generally set the ratio of MLP (i.e., $\frac{K}{C}$ ) to 2 or 4 in ViT models. The linearized MLP can be formulated as $X^{(i+1)} = (X^{(i)}\mathcal{W}_1^{(i)})\mathcal{W}_2^{(i)} = X^{(i)}(\mathcal{W}_1^{(i)}\mathcal{W}_2^{(i)})$ . In this way, $\mathcal{W}_1^{(i)}\mathcal{W}_2^{(i)}$ is fused into $\mathcal{W}_f^{(i)} \in \mathbb{R}^{C \times C}$ , which optimizes two high-dimensional MatMuls to only a single low-dimensional MatMul, further reducing the latency of MLP. + +Adding additional activations. After GeLU removal and linear fusion, there is no non-linearity in these tokens. To boost the accuracy, we additionally add a non-linear function after the fused linear positions. Here, we choose to add ReLU which incurs a cheaper cost than GeLU. + +# 5. Experiments + +# 5.1. Experimental Setup + +Experimental and MPC settings. In our experiments, we leverage the SecretFlow (SPU [39] V0.3.1b0)2 framework for private inference, which is popular for privacy- + +preserving deep learning. We adopt the SEMI-2K [9] protocol, which is a semi-honest two-party computation protocol3. We follow Cheetah [22] and use the WAN mode for communication. Specifically, the communication bandwidth between the cloud instances is set to 44 MBps and the round-trip time is set to 40ms. Our experiments are evaluated on an Intel Xeon CPU@2.40 GHz with 62 GB RAM. + +Model architectures and datasets. Many researches have studied training ViTs on small datasets [12, 19, 23, 32, 35]. We consider two ViT architectures on three commonly used datasets following [19]. For the CIFAR-10/100 dataset, we set the ViT depth, # heads, hidden dimension, and patch size to 7, 4, 256, and 4, respectively. For TinyImageNet dataset, we set the ViT depth, # heads, hidden dimension, and patch size to 9, 12, 192, and 4, respectively. + +Searching settings. We run the NAS algorithm for 300 epochs with AdamW optimizer and a cosine learning rate across three datasets. We set $\epsilon = 10^{-8}$ to avoid the zero denominator in RSAatt, and $\lambda = 10^{-5}$ . + +Training settings. Following [19], we train the searched heterogeneous ViTs for 600 epochs on CIFAR-10/100 and 300 epochs on Tiny/ImageNet. We leverage data augmentations as [19]. For KD, we set the temperature $\mathcal{T}$ to 1, and set $\chi, \beta, \gamma$ to 1 as well. To explore the trade-off between inference accuracy and latency, we set $\mu$ to $\{0.1, 0.3, 0.5, 0.7\}$ . + +# 5.2. Comparison with Prior-Art Efficient Attentions + +Baselines. We compare MPCViT with prior-art models on the inference accuracy and efficiency. We compare with MPCFormer [33], Linformer [58, 60], THE-X [6] and ViT variants in Table 2. Linformer is studied in [60] as an efficient Transformer variant for MPC and the compression rate of attention dimension is also defined as $\mu$ . For networks compared with MPCViT, we only modify attention layer and keep MLP unchanged as the baseline ViT. For $\mathrm{MPCViT^{+}}$ , we optimize attention and MLP simultaneously. + +Results and analysis. The main results are shown in Figure 7, where we report top-1 accuracy across three datasets and the network inference latency. The main findings are as follows: + +1) MPCViT outperforms prior-art methods. Without KD, on Tiny-ImageNet, MPCViT with $\mu = 0.1$ outperforms Linformer with $\mu = 0.7$ by $0.57\%$ better accuracy with $4.9\times$ latency reduction; Compared with THE-X, MPCViT achieve $3.6\%$ accuracy improvement with $1.9\times$ latency reduction; +2) with proper KD, MPCViT even achieves $1.9\%$ and $1.3\%$ better accuracy with $6.2 \times$ and $2.9 \times$ latency reduction with $\mu = 0.1$ and 0.3, compared with baseline ViT and MPCFormer on Tiny-ImageNet, respectively; + +Figure 7. Top-1 Accuracy and inference latency comparison with baseline ViTs across three datasets. +![](images/f67c43023e97fa720a08debae52b104d9347a318e8d586b96fc1a95b85c7975d.jpg) +- MPCViT w/o KD (ours) - MPCViT w/ KD (ours) Linformer - ReLU Softmax ViT - ScaleAttn ViT - THE-X + +![](images/b40f7df352253d606c6384dc36b32dcbf74e255e9b8ee633040552c1d93a1948.jpg) +Softmax-ScaleAttn ViT Softmax ViT MPCViT w/ Per-layer Search MPCFormer w/KD MPFCorner w/o KD + +![](images/f88ff4d0affc061ab1047c92c2fb697346fc1857b428795201ce1bbbd2d40afa.jpg) + +![](images/b4c2300e2cf1e73818bfec01f0fed8f8961791a2ceed4369c4c5720e689ea02c.jpg) +Figure 8. Latency and communication cost comparison of different layers in the 9-layer 12-head ViT with $\mu = 0.5$ . + +3) we mix Softmax attention and ScaleAttn. Although it has a slightly higher accuracy in plaintext inference, it incurs at least $1.4 \times$ and $1.2 \times$ latency on CIFAR-10/100 and Tiny/ImageNet compared with MPCViT. + +We visualize the latency and communication cost comparison of Softmax ViT, ReLU Softmax ViT, and MPCViT in Figure 8. We can observe the latency changes proportionally with the communication. Also, we observe for MPCViT, RSAattn in middle layers (e.g., layer 2 to layer 5) tend to be preserved while RSAattn in early and final layers are likely to be replaced with ScaleAttn. + +# 5.3. Comparison on Structure Granularities + +The choice of search space is important for MPCViT, so we compare different structure granularities of search space proposed in §4.2. We use the CIFAR-10 dataset for the comparison. As shown in Table 3, the head-wise search space achieves the best accuracy. We hypothesize although rowwise structure leads to the largest search space, such a fine-grained search space may introduce difficulties in NAS, and hence, leads to network architecture with inferior accuracy. Head-wise search space achieves the right balance between flexibility and optimizability. + +# 5.4. Ablation Study of MPCViT + +Contribution of KD. One of our key techniques for training heterogeneous ViT is KD. We enumerate different + +Table 3. Top-1 accuracy (%) comparison with different structure granularities of attention search space with different $\mu$ . + +
GranularityLayer-wiseRow-wiseHead-wise
μ = 0.593.0193.1693.21
μ = 0.793.3293.1393.38
+ +Table 4. Top-1 Accuracy $(\%)$ comparison of different combinations of training loss function with $\mu = 0.7$ + +
CELogits-based KDFeature-based KDCIFAR-10Tiny-ImageNet
✓93.3859.02
✓✓94.1862.39
✓✓94.1262.26
✓✓94.1461.80
✓✓✓94.2763.03
+ +combinations of KD and the results are shown in Table 4. We find that: 1) both logits-based and feature-based KD significantly improve the performance of ViT compared to using cross-entropy loss only; and 2) combining the two KD losses further improves the accuracy, especially on a larger dataset. The above findings indicate the importance of KD and the indispensability of three parts of $\mathcal{L}_{train}$ . + +Consistency and scalability of NAS algorithm. We hope our NAS algorithm to be robust against hyperparameter choices and datasets. To analyze this consistency of our algorithm, we adjust the coefficient $\lambda$ to three different values, i.e., $10^{-3}, 10^{-4}, 10^{-5}$ , and train a 7-layer ViT with 4 heads. We visualize the distribution of the architecture parameter $\alpha$ in Figure 9, and we find that $\alpha$ in each layer has a quite similar trend under different $\lambda$ 's. Furthermore, when we change the number of heads to 8, or even train the same architecture on different datasets like CIFAR-100 and ImageNet, the distribution still shows a similar trend, empirically proving the consistency and scalability of our proposed NAS algorithm. Appendix F shows more distribution trends under other settings. + +Comparison with per-layer search. We also compare MPCViT with per-layer search which replaces RSA ttn heads in each layer uniformly given a certain $\mu$ across three + +![](images/41d509e09a40f9937343b174f4d3340846d1bdcb18c6435f4f1a0030c24e1bfa.jpg) + +![](images/2ebc105be725a058dedd504b816301009ae3ab96525dc380b8d56cb549902ec7.jpg) +Figure 9. The distribution of architecture parameter $\alpha$ for each head under different $\lambda$ and different # heads on different datasets. We draw the average $\alpha$ in each layer to show the similar trend. + +datasets. As shown in Figure 7, MPCViT achieves a better Pareto front for accuracy and efficiency compared to the per-layer NAS. The results demonstrate the importance to search and replace RSAtn heads across different layers. + +# 5.5. MPCViT+ Evaluation + +As shown in Figure 7, when $\mu$ decreases to 0.1, the major latency bottleneck comes from GeLU in MLP. We evaluate MPCViT+ for GeLU reduction on CIFAR-10/100 datasets with KD, which correspond to the ViT models with significant GeLU latency. We take token-wise optimization as an example (exploration for other granularity, i.e., layer-wise is shown in Appendix E), and control the GeLU linearization rate using a threshold $\sigma$ such that $\beta \leftarrow 0(\beta \leq \sigma)$ while $\beta \leftarrow 1(\beta >\sigma)$ . As shown in Figure 10, GeLU linearization leads to a little accuracy degradation, indicating that GeLU plays an important role in ViTs. MPCViT+ further reduces the latency on the basis of attention optimization, which proves the effectiveness of MPCViT+. + +Ablation study of additional ReLU. To analyze the help of adding additional ReLU after the fused linear layer, we fix $\sigma = 0.75$ and perform the ablation study for MPCViT $^{+}$ under different latency constraints on CIFAR-10 dataset in Table 5. The results show that additional ReLU improves the representation ability of MPCViT $^{+}$ . + +Table 5. Ablation study of adding additional ReLU after the fused linear layer under different latency constraints. + +
μ0.30.7
Accuracy (%)Latency (s)Accuracy (%)Latency (s)
MPCViT+93.9243.8894.2754.56
w/o ReLU93.7241.3793.8152.11
+ +![](images/962443157ace73d90e6a5aa7a29b14025b7483af36a183b369b32fa47cfdbc26.jpg) +Figure 10. Comparison between MPCViT and MPCViT+. + +![](images/335b881b5710163e9ea935136e4978b341b135ca3f1926a835d686f4b634e513.jpg) + +# 6. Conclusion + +In this paper, we present an MPC-friendly ViT family, dubbed MPCViT, to enable accurate yet efficient ViT inference in MPC. We propose a heterogeneous attention optimization space, and design an MPC-aware differentiable NAS algorithm to explore the search space. To further boost the inference efficiency, we propose $\mathrm{MPCViT^{+}}$ to jointly optimize attention and MLP. Extensive experiments demonstrate that MPCViT consistently outperforms prior-art ViT architectures with both lower latency and higher accuracy. Our method can be further applied to large language models (LLMs) including BERT and GPT. + +# Acknowledgement + +This work is supported in part by the NSFC (62125401) and the 111 Project (B18001). + +# References + +[1] Saba Akram and Quarrat Ul Ann. Newton raphson method. International Journal of Scientific & Engineering Research, 6(7):1748-1752, 2015. 13 +[2] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In Proceedings of the IEEE/CVF international conference on computer vision, pages 6836-6846, 2021. 1 +[3] Gilad Asharov, Yehuda Lindell, Thomas Schneider, and Michael Zohner. More efficient oblivious transfer and extensions for faster secure computation. In ACM SIGSAC conference on Computer & Communications Security (CCS), pages 535-548, 2013. 14 +[4] Daniel Bolya, Cheng-Yang Fu, Xiaoliang Dai, Peizhao Zhang, and Judy Hoffman. Hydra attention: Efficient attention with many heads. In European Conference on Computer Vision, pages 35-49. Springer, 2022. 2 +[5] Jason Ross Brown, Yiren Zhao, Ilia Shumailov, and Robert D Mullins. Dartformer: Finding the best type of attention. arXiv preprint arXiv:2210.00641, 2022. 2, 5 +[6] Tianyu Chen, Hangbo Bao, Shaohan Huang, Li Dong, Binxing Jiao, Daxin Jiang, Haoyi Zhou, Jianxin Li, and Furu Wei. THE-X: Privacy-preserving transformer inference with homomorphic encryption. In Findings of the Association for Computational Linguistics: ACL 2022, pages 3510-3520, + +Dublin, Ireland, May 2022. Association for Computational Linguistics. 2, 3, 7 +[7] Minsu Cho, Zahra Ghodsi, Brandon Reagen, Siddharth Garg, and Chinmay Hegde. Sphynx: Relu-efficient network design for private inference. arXiv preprint arXiv:2106.11755, 2021. 3 +[8] Minsu Cho, Ameya Joshi, Brandon Reagen, Siddharth Garg, and Chinmay Hegde. Selective network linearization for efficient private inference. In International Conference on Machine Learning, pages 3947-3961. PMLR, 2022. 3, 15 +[9] Ronald Cramer, Ivan Damgård, Daniel Escudero, Peter Scholl, and Chaoping Xing. SpdZ2k: Efficient mpc mod 2k for dishonest majority. In Annual International Cryptology Conference. Springer, pages 769-798, 2018. 4, 7, 13 +[10] Xiaoliang Dai, Peizhao Zhang, Bichen Wu, Hongxu Yin, Fei Sun, Yanghan Wang, Marat Dukhan, Yunqing Hu, Yiming Wu, Yangqing Jia, et al. Chamnet: Towards efficient network design through platform-aware model adaptation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11398-11407, 2019. 5 +[11] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In 9th International Conference on Learning Representations, ICLR 2021, Virtual Event, Austria, May 3-7, 2021. OpenReview.net, 2021. 1, 2, 4, 13 +[12] Hanan Gani, Muzammal Naseer, and Mohammad Yaqub. How to train vision transformer on small-scale datasets? arXiv preprint arXiv:2210.07240, 2022. 7 +[13] Zahra Ghodsi, Akshaj Kumar Veldanda, Brandon Reagen, and Siddharth Garg. Cryptonas: Private inference on a relu budget. Advances in Neural Information Processing Systems, 33:16961-16971, 2020. 3 +[14] Oded Goldreich. Secure multi-party computation. 1998. 1, 3 +[15] Chengyue Gong, Dilin Wang, Meng Li, Xinlei Chen, Zhicheng Yan, Yuandong Tian, Vikas Chandra, et al. Nasvit: Neural architecture search for efficient vision transformers with gradient conflict aware supernet training. In International Conference on Learning Representations, 2021. 1 +[16] Jiaqi Gu, Hyoukjun Kwon, Dilin Wang, Wei Ye, Meng Li, Yu-Hsin Chen, Liangzhen Lai, Vikas Chandra, and David Z Pan. Multi-scale high-resolution vision transformer for semantic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12094-12103, 2022. 1 +[17] Minghao Guo, Zhao Zhong, Wei Wu, Dahua Lin, and Junjie Yan. Irlas: Inverse reinforcement learning for architecture search. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9021-9029, 2019. 5 +[18] Meng Hao, Hongwei Li, Hanxiao Chen, Pengzhi Xing, Guowen Xu, and Tianwei Zhang. Iron: Private inference on transformers. Advances in neural information processing systems, 2022. 3 +[19] Ali Hassani, Steven Walton, Nikhil Shah, Abulikemu Abuduweili, Jiachen Li, and Humphrey Shi. Escaping the + +big data paradigm with compact transformers. arXiv preprint arXiv:2104.05704, 2021. 7 +[20] Dan Hendrycks and Kevin Gimpel. Gaussian error linear units (gelus). arXiv preprint arXiv:1606.08415, 2016. 13 +[21] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, et al. Distilling the knowledge in a neural network. arXiv preprint arXiv:1503.02531, 2(7), 2015. 6 +[22] Zhicong Huang, Wen jie Lu, Cheng Hong, and Jiansheng Ding. Cheetah: Lean and fast secure Two-Party deep neural network inference. In USENIX Security Symposium (USENIX Security), pages 809–826, Boston, MA, Aug. 2022. 4, 7, 13 +[23] Ethan Huynh. Vision transformers in 2022: An update on tiny imagenet. arXiv preprint arXiv:2205.10660, 2022. 7 +[24] Yesmina JAAFra, Jean Luc Laurent, Aline Deruyver, and Mohamed Saber Naceur. Reinforcement learning for neural architecture search: A review. Image and Vision Computing, 89:57-66, 2019. 5 +[25] Nandan Kumar Jha, Zahra Ghodsi, Siddharth Garg, and Brandon Reagen. Deepreduce: Relu reduction for fast private inference. In International Conference on Machine Learning, pages 4839-4849. PMLR, 2021. 3 +[26] Nandan Kumar Jha and Brandon Reagen. Deepreshape: Redesigning neural networks for efficient private inference. arXiv preprint arXiv:2304.10593, 2023. 3 +[27] Weiwen Jiang, Lei Yang, Edwin Hsing-Mean Sha, Qingfeng Zhuge, Shouzhen Gu, Sakyasingha Dasgupta, Yiyu Shi, and Jingtong Hu. Hardware/software co-exploration of neural architectures. IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 39(12):4805-4815, 2020. 5 +[28] Jacob Devlin Ming-Wei Chang Kenton and Lee Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of naacL-HLT, volume 1, page 2, 2019. 2 +[29] Nikita Kitaev, Lukasz Kaiser, and Anselm Levskaya. Reformer: The efficient transformer. In 8th International Conference on Learning Representations, ICLR 2020, Addis Ababa, Ethiopia, April 26-30, 2020. OpenReview.net, 2020. 2 +[30] Brian Knott, Shobha Venkataraman, Awni Hannun, Shubho Sengupta, Mark Ibrahim, and Laurens van der Maaten. Crypten: Secure multi-party computation meets machine learning. Advances in Neural Information Processing Systems, 34:4961-4973, 2021. 13 +[31] Souvik Kundu, Shunlin Lu, Yuke Zhang, Jacqueline Tiffany Liu, and Peter A. Beerel. Learning to linearize deep neural networks for secure and efficient private inference. In The Eleventh International Conference on Learning Representations, ICLR 2023, Kigali, Rwanda, May 1-5, 2023. OpenReview.net, 2023. 3 +[32] Seunghoon Lee, Seunghyun Lee, and Byung Cheol Song. Improving vision transformers to learn small-size dataset from scratch. IEEE Access, 10:123212-123224, 2022. 7 +[33] Dacheng Li, Hongyi Wang, Rulin Shao, Han Guo, Eric P. Xing, and Hao Zhang. MPCFORMER: fast, performant and provate transformer inference with MPC. In The Eleventh International Conference on Learning Representations, ICLR 2023, Kigali, Rwanda, May 1-5, 2023. OpenReview.net, + +2023. 2, 3, 4, 7, 14 +[34] Zhexin Li, Tong Yang, Peisong Wang, and Jian Cheng. Q-vit: Fully differentiable quantization for vision transformer. arXiv preprint arXiv:2201.07703, 2022. 5 +[35] Yahui Liu, Enver Sangineto, Wei Bi, Nicu Sebe, Bruno Lepri, and Marco Nadai. Efficient training of visual transformers with small datasets. Advances in Neural Information Processing Systems, 34:23818-23830, 2021. 7 +[36] Zexiang Liu, Dong Li, Kaiyue Lu, Zhen Qin, Weixuan Sun, Jiacheng Xu, and Yiran Zhong. Neural architecture search on efficient transformers and beyond. arXiv preprint arXiv:2207.13955, 2022. 5 +[37] Qian Lou, Yilin Shen, Hongxia Jin, and Lei Jiang. Safenet: A secure, accurate and fast neural network inference. In International Conference on Learning Representations, 2020. 3 +[38] Jiachen Lu, Jinghan Yao, Junge Zhang, Xiatian Zhu, Hang Xu, Weiguo Gao, Chunjing Xu, Tao Xiang, and Li Zhang. Soft: Softmax-free transformer with linear complexity. Advances in Neural Information Processing Systems, 34:21297-21309, 2021. 2 +[39] Junming Ma, Yancheng Zheng, Jun Feng, Derun Zhao, Haoqi Wu, Wenjing Fang, Jin Tan, Chaofan Yu, Benyu Zhang, and Lei Wang. SecretFlow-SPU: A performant and User-Friendly framework for Privacy-Preserving machine learning. In 2023 USENIX Annual Technical Conference (USENIX ATC 23), pages 17–33, Boston, MA, July 2023. USENIX Association. 7 +[40] Andre Martins and Ramon Astudillo. From softmax to sparsemax: A sparse model of attention and multi-label classification. In International conference on machine learning, pages 1614-1623. PMLR, 2016. 4, 14 +[41] Paul Michel, Omer Levy, and Graham Neubig. Are sixteen heads really better than one? Advances in neural information processing systems, 32, 2019. 5, 15 +[42] Pratyush Mishra, Ryan Lehmkuhl, Akshayaram Srinivasan, Wenting Zheng, and Raluca Ada Popa. Delphi: A cryptographic inference service for neural networks. In USENIX Security Symposium, pages 2505-2522, 2020. 1, 3 +[43] Payman Mohassel and Peter Rindal. Aby3: A mixed protocol framework for machine learning. In Proceedings of the 2018 ACM SIGSAC conference on computer and communications security, pages 35-52, 2018. 3 +[44] Payman Mohassel and Yupeng Zhang. Securel: A system for scalable privacy-preserving machine learning. In IEEE symposium on security and privacy (S&P), pages 19-38. IEEE, 2017. 3, 4 +[45] Moni Naor and Benny Pinkas. Computationally secure oblivious transfer. Journal of Cryptology, 18(1):1-35, 2005. 14 +[46] Zizheng Pan, Bohan Zhuang, Haoyu He, Jing Liu, and Jianfei Cai. Less is more: Pay less attention in vision transformers. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 2035-2043, 2022. 5 +[47] Hongwu Peng, Shanglin Zhou, Yukui Luo, Shijin Duan, Nuo Xu, Ran Ran, Shaoyi Huang, Chenghong Wang, Tong Geng, Ang Li, et al. Polympcnet: Towards relu-free neural architecture search in two-party computation based private inference. arXiv preprint arXiv:2209.09424, 2022. 3 + +[48] Hongwu Peng, Shanglin Zhou, Yukui Luo, Nuo Xu, Shijin Duan, Ran Ran, Jiahui Zhao, Shaoyi Huang, Xi Xie, Chenghong Wang, et al. Rrnet: Towards relu-reduced neural network for two-party computation based private inference. arXiv preprint arXiv:2302.02292, 2023. 3 +[49] Zhen Qin, Weixuan Sun, Hui Deng, Dongxu Li, Yunshen Wei, Baohong Lv, Junjie Yan, Lingpeng Kong, and Yiran Zhong. cosformer: Rethinking softmax in attention. In The Tenth International Conference on Learning Representations, ICLR 2022, Virtual Event, April 25-29, 2022. OpenReview.net, 2022. 2 +[50] Deevashwer Rathee, Mayank Rathee, Rahul Kranti Kiran Goli, Divya Gupta, Rahul Sharma, Nishanth Chandran, and Aseem Rastogi. Sirnn: A math library for secure rn n inference. In 2021 IEEE Symposium on Security and Privacy (SP), pages 1003-1020. IEEE, 2021. 14 +[51] Deevashwer Rathee, Mayank Rathee, Nishant Kumar, Nishanth Chandran, Divya Gupta, Aseem Rastogi, and Rahul Sharma. Cryptflow2: Practical 2-party secure inference. In ACM SIGSAC Conference on Computer and Communications Security (CCS), pages 325-342, 2020. 1 +[52] Adi Shamir. How to share a secret. Communications of the ACM, 22(11):612-613, 1979. 13 +[53] Jeong-geun Song. Ufo-vit: High performance linear vision transformer without softmax. arXiv preprint arXiv:2109.14382, 2021. 2, 4, 14 +[54] Xiu Su, Shan You, Jiyang Xie, Mingkai Zheng, Fei Wang, Chen Qian, Changshui Zhang, Xiaogang Wang, and Chang Xu. Vitas: Vision transformer architecture search. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXI, pages 139-157. Springer, 2022. 5 +[55] Mingxing Tan, Bo Chen, Ruoming Pang, Vijay Vasudevan, Mark Sandler, Andrew Howard, and Quoc V Le. Mnasnet: Platform-aware neural architecture search for mobile. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2820-2828, 2019. 5 +[56] Elena Voita, David Talbot, Fedor Moiseev, Rico Sennrich, and Ivan Titov. Analyzing multi-head self-attention: Specialized heads do the heavy lifting, the rest can be pruned. In Anna Korhonen, David R. Traum, and Lluis Marquez, editors, Proceedings of the 57th Conference of the Association for Computational Linguistics, ACL 2019, Florence, Italy, July 28- August 2, 2019, Volume 1: Long Papers, pages 5797-5808. Association for Computational Linguistics, 2019. 5, 15 +[57] Kuan Wang, Zhijian Liu, Yujun Lin, Ji Lin, and Song Han. Haq: Hardware-aware automated quantization with mixed precision. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 8612-8620, 2019. 5 +[58] Sinong Wang, Belinda Z Li, Madian Khabsa, Han Fang, and Hao Ma. Linformer: Self-attention with linear complexity. arXiv preprint arXiv:2006.04768, 2020. 2, 4, 7, 14 +[59] Xiaolong Wang, Ross Girshick, Abhinav Gupta, and Kaiming He. Non-local neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 7794-7803, 2018. 3, 4 +[60] Yongqin Wang, G Edward Suh, Wenjie Xiong, Benjamin + +Lefaudeau, Brian Knott, Murali Annavaram, and Hsien-Hsin S Lee. Characterization of mpc-based private inference for transformer-based models. In 2022 IEEE International Symposium on Performance Analysis of Systems and Software (ISPASS), pages 187-197. IEEE, 2022. 1, 7, 13, 14 +[61] Bichen Wu, Xiaoliang Dai, Peizhao Zhang, Yanghan Wang, Fei Sun, Yiming Wu, Yuandong Tian, Peter Vajda, Yangqing Jia, and Kurt Keutzer. Fbnet: Hardware-aware efficient convnet design via differentiable neural architecture search. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10734-10742, 2019. 5 +[62] Mengzhou Xia, Zexuan Zhong, and Danqi Chen. Structured pruning learns compact and accurate models. In Smaranda Muresan, Preslav Nakov, and Aline Villavicencio, editors, Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), ACL 2022, Dublin, Ireland, May 22-27, 2022, pages 1513-1528. Association for Computational Linguistics, 2022. 15 +[63] Andrew C Yao. Protocols for secure computations. In 23rd annual symposium on foundations of computer science (sfcs 1982), pages 160-164. IEEE, 1982. 14 +[64] Pengchuan Zhang, Xiyang Dai, Jianwei Yang, Bin Xiao, Lu Yuan, Lei Zhang, and Jianfeng Gao. Multi-scale vision longformer: A new vision transformer for high-resolution image encoding. In Proceedings of the IEEE/CVF international conference on computer vision, pages 2998-3008, 2021. 1 \ No newline at end of file diff --git a/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/images.zip b/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..9b63fb6e1baf8f1d01cc1eba0269eff03146a366 --- /dev/null +++ b/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:381633d3933d39a67862b77a74723425f51b82a8e906a85e97ebef4e0f63f8d3 +size 635621 diff --git a/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/layout.json b/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..e70974bd934888a2e8c2f6895cfe2dc9554ed076 --- /dev/null +++ b/2023/MPCViT_ Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention/layout.json @@ -0,0 +1,11294 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 105, + 102, + 489, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 105, + 102, + 489, + 140 + ], + "spans": [ + { + "bbox": [ + 105, + 102, + 489, + 140 + ], + "type": "text", + "content": "MPCViT: Searching for Accurate and Efficient MPC-Friendly Vision Transformer with Heterogeneous Attention" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "spans": [ + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "text", + "content": "Wenxuan Zeng" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "text", + "content": " Meng Li" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "text", + "content": " Wenjie Xiong" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "text", + "content": " Tong Tong" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "text", + "content": " Wen-jie Lu" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "text", + "content": " Jin Tan" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "text", + "content": " Runsheng Wang" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "text", + "content": " Ru Huang" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "text", + "content": "Peking University " + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "text", + "content": "Virginia Tech " + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 113, + 159, + 477, + 204 + ], + "type": "text", + "content": "Ant Group" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 111, + 205, + 481, + 232 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 205, + 481, + 232 + ], + "spans": [ + { + "bbox": [ + 111, + 205, + 481, + 232 + ], + "type": "text", + "content": "{zwx.andy,tongtong}@stu.pku.edu.cn, {meng.li,wrs,ruhuang}@pku.edu.cn, wenjiex@vt.edu, {juhou.lwj,tanjin.tj}@antgroup.com" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 258, + 192, + 272 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 258, + 192, + 272 + ], + "spans": [ + { + "bbox": [ + 143, + 258, + 192, + 272 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "spans": [ + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "text", + "content": "Secure multi-party computation (MPC) enables computation directly on encrypted data and protects both data and model privacy in deep learning inference. However, existing neural network architectures, including Vision Transformers (ViTs), are not designed or optimized for MPC and incur significant latency overhead. We observe Softmax accounts for the major latency bottleneck due to a high communication complexity, but can be selectively replaced or linearized without compromising the model accuracy. Hence, in this paper, we propose an MPC-friendly ViT, dubbed MPCViT, to enable accurate yet efficient ViT inference in MPC. Based on a systematic latency and accuracy evaluation of the Softmax attention and other attention variants, we propose a heterogeneous attention optimization space. We also develop a simple yet effective MPC-aware neural architecture search algorithm for fast Pareto optimization. To further boost the inference efficiency, we propose MPCViT" + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "inline_equation", + "content": "^+" + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "text", + "content": ", to jointly optimize the Softmax attention and other network components, including GeLU, matrix multiplication, etc. With extensive experiments, we demonstrate that MPCViT achieves " + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "inline_equation", + "content": "1.9\\%" + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "inline_equation", + "content": "1.3\\%" + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "inline_equation", + "content": "3.6\\%" + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "text", + "content": " higher accuracy with " + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "inline_equation", + "content": "6.2\\times" + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "inline_equation", + "content": "2.9\\times" + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "inline_equation", + "content": "1.9\\times" + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "text", + "content": " latency reduction compared with baseline ViT, MPCFormer and THE-X on the Tiny-ImageNet dataset, respectively. MPCViT" + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "inline_equation", + "content": "^+" + }, + { + "bbox": [ + 46, + 284, + 290, + 608 + ], + "type": "text", + "content": " further achieves a better Pareto front compared with MPCViT. The code and models for evaluation are available at https://github.com/PKU-SEC-Lab/mpcvit." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 628, + 128, + 641 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 628, + 128, + 641 + ], + "spans": [ + { + "bbox": [ + 47, + 628, + 128, + 641 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 648, + 288, + 698 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 648, + 288, + 698 + ], + "spans": [ + { + "bbox": [ + 46, + 648, + 288, + 698 + ], + "type": "text", + "content": "As machine learning models are handling increasingly sensitive data and tasks, privacy has become one of the major concerns during the model deployment. Secure multi-party computation (MPC) [14] can protect the privacy of" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 308, + 258, + 391, + 344 + ], + "blocks": [ + { + "bbox": [ + 308, + 258, + 391, + 344 + ], + "lines": [ + { + "bbox": [ + 308, + 258, + 391, + 344 + ], + "spans": [ + { + "bbox": [ + 308, + 258, + 391, + 344 + ], + "type": "image", + "image_path": "51f3964077c43d86aff9aa56b9faab1fc634fd7c6f3e242b9d1b85dac77fb754.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 347, + 547, + 381 + ], + "lines": [ + { + "bbox": [ + 305, + 347, + 547, + 381 + ], + "spans": [ + { + "bbox": [ + 305, + 347, + 547, + 381 + ], + "type": "text", + "content": "Figure 1. The latency breakdown of a Transformer block w.r.t (a) # heads and (b) # tokens; and (c) the relative error of Softmax and ReLU Softmax with different input variances." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 391, + 258, + 473, + 344 + ], + "blocks": [ + { + "bbox": [ + 391, + 258, + 473, + 344 + ], + "lines": [ + { + "bbox": [ + 391, + 258, + 473, + 344 + ], + "spans": [ + { + "bbox": [ + 391, + 258, + 473, + 344 + ], + "type": "image", + "image_path": "8924f7f556a5fe338742235b27bb24aa1a5e9cf97969c134f67c403abe275b0b.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 473, + 258, + 545, + 344 + ], + "blocks": [ + { + "bbox": [ + 473, + 258, + 545, + 344 + ], + "lines": [ + { + "bbox": [ + 473, + 258, + 545, + 344 + ], + "spans": [ + { + "bbox": [ + 473, + 258, + 545, + 344 + ], + "type": "image", + "image_path": "12b0bc74a33f1db51d5dc8d51a6897463daac312638274cf9415baa3cc7c74fd.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 401, + 545, + 425 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 401, + 545, + 425 + ], + "spans": [ + { + "bbox": [ + 304, + 401, + 545, + 425 + ], + "type": "text", + "content": "both data and deep neural network (DNN) models and has gained a lot of attention in recent years [42, 51, 60]." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 426, + 546, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 426, + 546, + 700 + ], + "spans": [ + { + "bbox": [ + 304, + 426, + 546, + 700 + ], + "type": "text", + "content": "However, existing DNN architectures, especially the recently proposed Vision Transformers (ViTs) [2, 11, 64], are not designed or optimized for MPC (the high-level private ViT inference framework in MPC is shown in Figure 2 and Appendix A.1). Although ViTs have achieved superior performance for various vision tasks [2, 15, 16, 64], they face several realistic limitations when directly deployed in MPC: 1) communication overhead: in contrast to regular inference on plaintext, operations like Softmax, GeLU, max, etc, require intensive communication in MPC, which usually dominates the total inference latency [42, 60]. For example, Softmax is usually very lightweight in plaintext inference. However, as shown in Figure 1(a) and Figure 1(b), it accounts for the majority of the Transformer inference latency due to the high communication complexity; 2) approximation error: operations like exponential, tanh, reciprocal, etc, cannot be computed directly and require iterative approximation, limiting the computation accuracy. For instance, as shown in Figure 1(c), the relative error of Softmax significantly increases when the input variance is large due to its narrow dynamic range [60]. In contrast, replacing exponential in Softmax with ReLU reduces the relative error drastically (denoted as ReLU Softmax in §2.2)." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "type": "text", + "content": "Numerous efficient Transformer variants have been pro" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 703, + 135, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 703, + 135, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 703, + 135, + 712 + ], + "type": "text", + "content": "*Corresponding author." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5052" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 75, + 72, + 521, + 178 + ], + "blocks": [ + { + "bbox": [ + 75, + 72, + 521, + 178 + ], + "lines": [ + { + "bbox": [ + 75, + 72, + 521, + 178 + ], + "spans": [ + { + "bbox": [ + 75, + 72, + 521, + 178 + ], + "type": "image", + "image_path": "34002c189cff84ca15fb9c50cf7a5479470d1d7120442c1472bf183e373513f0.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 120, + 179, + 470, + 190 + ], + "lines": [ + { + "bbox": [ + 120, + 179, + 470, + 190 + ], + "spans": [ + { + "bbox": [ + 120, + 179, + 470, + 190 + ], + "type": "text", + "content": "Figure 2. An overall illustration of private Vision Transformer inference in the MPC framework." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 210, + 289, + 426 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 210, + 289, + 426 + ], + "spans": [ + { + "bbox": [ + 46, + 210, + 289, + 426 + ], + "type": "text", + "content": "posed in recent years [5, 29, 49, 58]. Linear Transformers, including Linformer [58], cosFormer [49], Reformer [29], etc, reduce the quadratic computation complexity of the attentions and significantly accelerate model inference for long sequences. However, these Transformer optimizations have primarily focused on reducing the network computation. Hence, they either retain complex non-linear functions or still require iterative approximation, both resulting in intensive communication overhead in MPC. Recently, MPC-Former [33] and THE-X [6] are proposed to improve the inference efficiency of BERT [28] in MPC. MPCFormer simplifies Softmax by replacing exponential with a more MPC-friendly quadratic operation while THE-X approximates Softmax with a small estimation network. However, their attention variants is not flexible and can still be too expensive for certain latency constraints. Moreover, the network-level optimization suffers from a large accuracy degradation when directly applied to vision tasks." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 427, + 287, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 427, + 287, + 594 + ], + "spans": [ + { + "bbox": [ + 46, + 427, + 287, + 594 + ], + "type": "text", + "content": "In this work, we first breakdown Softmax into more atomic operations and analyze their impact on the inference accuracy and efficiency, based on which we propose and compare a set of attention variants comprehensively. The comparison enables us to find MPC-friendly attention variants, which are either highly accurate or highly efficient. We further observe not all attentions are equally important within a ViT. Based on these observations, we propose the first MPC-friendly ViT architecture, dubbed MPCViT. MPCViT features a heterogeneous attention design space to explore the trade-off between accuracy and efficiency, and an MPC-aware differentiable neural architecture search (NAS) algorithm for effective Pareto optimization. Our contributions can be summarized as follows:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 58, + 605, + 288, + 714 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 58, + 605, + 287, + 654 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 605, + 287, + 654 + ], + "spans": [ + { + "bbox": [ + 58, + 605, + 287, + 654 + ], + "type": "text", + "content": "- We breakdown Softmax and reveal the impact of atomic operations on the inference accuracy and efficiency, based on which a heterogeneous attention design space is proposed." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 58, + 665, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 665, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 58, + 665, + 288, + 714 + ], + "type": "text", + "content": "- We propose an effective MPC-aware differentiable NAS algorithm to explore the attention design space based on real latency measurements instead of proxies. To the best of our knowledge, we make the first" + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 324, + 210, + 545, + 234 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 324, + 210, + 545, + 234 + ], + "spans": [ + { + "bbox": [ + 324, + 210, + 545, + 234 + ], + "type": "text", + "content": "attempt to introduce the MPC-aware NAS to optimize ViT inference in MPC." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 242, + 545, + 370 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 317, + 242, + 545, + 315 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 242, + 545, + 315 + ], + "spans": [ + { + "bbox": [ + 317, + 242, + 545, + 315 + ], + "type": "text", + "content": "- Our MPC-friendly ViT model family, MPCViT, outperforms prior-art models in MPC in terms of both accuracy and efficiency. MPCViT achieves " + }, + { + "bbox": [ + 317, + 242, + 545, + 315 + ], + "type": "inline_equation", + "content": "1.9\\%" + }, + { + "bbox": [ + 317, + 242, + 545, + 315 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 317, + 242, + 545, + 315 + ], + "type": "inline_equation", + "content": "1.3\\%" + }, + { + "bbox": [ + 317, + 242, + 545, + 315 + ], + "type": "text", + "content": " higher accuracy with " + }, + { + "bbox": [ + 317, + 242, + 545, + 315 + ], + "type": "inline_equation", + "content": "6.2\\times" + }, + { + "bbox": [ + 317, + 242, + 545, + 315 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 317, + 242, + 545, + 315 + ], + "type": "inline_equation", + "content": "2.9\\times" + }, + { + "bbox": [ + 317, + 242, + 545, + 315 + ], + "type": "text", + "content": " latency reduction compared with baseline ViT and MPCFormer on Tiny-ImageNet dataset, respectively." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 317, + 322, + 545, + 370 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 322, + 545, + 370 + ], + "spans": [ + { + "bbox": [ + 317, + 322, + 545, + 370 + ], + "type": "text", + "content": "- We further extend MPCViT to optimize other Transformer components simultaneously with Softmax, named " + }, + { + "bbox": [ + 317, + 322, + 545, + 370 + ], + "type": "inline_equation", + "content": "\\mathrm{MPCViT}^+" + }, + { + "bbox": [ + 317, + 322, + 545, + 370 + ], + "type": "text", + "content": ", achieving an even better Pareto front compared with MPCViT." + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 380, + 492, + 393 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 380, + 492, + 393 + ], + "spans": [ + { + "bbox": [ + 306, + 380, + 492, + 393 + ], + "type": "text", + "content": "2. Preliminaries and Related Works" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 400, + 457, + 412 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 400, + 457, + 412 + ], + "spans": [ + { + "bbox": [ + 306, + 400, + 457, + 412 + ], + "type": "text", + "content": "2.1. ViT and Efficient Attention" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 418, + 545, + 503 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 418, + 545, + 503 + ], + "spans": [ + { + "bbox": [ + 304, + 418, + 545, + 503 + ], + "type": "text", + "content": "ViT architecture. ViT [11] has demonstrated a great potential to capture the long-range visual dependencies. It takes image patches as input and is composed of an input projection layer, a stack of Transformer layers, and a task-specific multi-layer perceptron (MLP) head. Each layer consists of a multi-head attention (MHA) layer and an MLP block. The core computation is the Softmax attention:" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 336, + 510, + 515, + 539 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 336, + 510, + 515, + 539 + ], + "spans": [ + { + "bbox": [ + 336, + 510, + 515, + 539 + ], + "type": "interline_equation", + "content": "\\operatorname {A t t e n t i o n} (Q, K, V) = \\operatorname {S o f t m a x} \\left(\\frac {Q K ^ {T}}{\\sqrt {d _ {k}}}\\right) V,", + "image_path": "e1b66b953f000fb6fdcde8ade9e5d05115e9e9ebe45edcb0966e9e59ace14ae4.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 545, + 545, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 545, + 545, + 594 + ], + "spans": [ + { + "bbox": [ + 304, + 545, + 545, + 594 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 545, + 545, + 594 + ], + "type": "inline_equation", + "content": "Q, K, V" + }, + { + "bbox": [ + 304, + 545, + 545, + 594 + ], + "type": "text", + "content": " are queries, keys and values, respectively. " + }, + { + "bbox": [ + 304, + 545, + 545, + 594 + ], + "type": "inline_equation", + "content": "d_{k}" + }, + { + "bbox": [ + 304, + 545, + 545, + 594 + ], + "type": "text", + "content": " denotes the embedding dimension of each key, and Softmax normalizes the attention map. The detailed explanation of ViT architecture is shown in Figure 2 and Appendix A.2." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "type": "text", + "content": "Linear attention. Linear attention has been widely studied in previous works [5, 29, 38, 49]. These works aim at reducing the quadratic increase of compute and memory by leveraging special kernel functions. Different kernel functions have been proposed in existing works [4, 49, 53, 58]. UFO-ViT [53] proposes to use " + }, + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\ell 2" + }, + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "type": "text", + "content": "-Norm as the kernel function while CosFormer [49] leverages the cosine distance kernel. Linformer [58] approximates self-attention by a low-rank matrix. Hydra Attention [4] proposes to use as many heads as possible to further reduce the computation" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5053" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 72, + 80, + 523, + 259 + ], + "blocks": [ + { + "bbox": [ + 125, + 69, + 465, + 80 + ], + "lines": [ + { + "bbox": [ + 125, + 69, + 465, + 80 + ], + "spans": [ + { + "bbox": [ + 125, + 69, + 465, + 80 + ], + "type": "text", + "content": "Table 1. Comparison among existing network optimizations for the efficient private inference." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 72, + 80, + 523, + 259 + ], + "lines": [ + { + "bbox": [ + 72, + 80, + 523, + 259 + ], + "spans": [ + { + "bbox": [ + 72, + 80, + 523, + 259 + ], + "type": "table", + "html": "
MethodModelTechniqueOptimized ComponentGranularityLinear Fusion
Delphi [42]CNNReLU-aware NASReLULayerX
DeepReDuce [25]CNNManually removalReLULayerX
CryptoNAS [13]CNNReLU-aware NASReLULayerX
SNL [8]CNNReLU-aware NASReLUChannel, pixelX
Sphinx [7]CNNBlock-level NASReLUBlockX
SENet [31]CNNSensitivity-aware alloc.ReLULayer, pixelX
RRNet [48]CNNHardware-aware NASReLULayerX
DeepReShape [26]CNNReLU-equalizationReLUStageX
SAFENet [31]CNNMixed-precision poly. approx.ReLUChannelX
THE-X [6]BERTPolynomial approx.GeLU, Softmax, LayerNormNetworkX
MPCFormer [33]BERTPolynomial approx.Softmax, GeLUNetworkX
MPCViT (ours)ViTMPC-aware NASSoftmaxLayer, head, rowX
Heterogeneous attention
MPC-aware NAS
MPCViT+ (ours)ViTHeterogeneous attentionSoftmax, GeLU, MatMulLayer, head, row, token✓
GeLU linearization
Linear fusion
", + "image_path": "bc13a5cd666ec5d9da0383f1e0fd08c8b35dfdff71cc9dc1126ee1bf53d86839.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 279, + 287, + 327 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 279, + 287, + 327 + ], + "spans": [ + { + "bbox": [ + 46, + 279, + 287, + 327 + ], + "type": "text", + "content": "complexity of the linear attention. However, these works primarily focus on reducing the network computation rather than the communication overhead and are not beneficial for ViT inference in MPC." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "spans": [ + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "text", + "content": "Non-local neural networks and Scaling attention. [59] presents a generic non-local operation to capture long-range dependencies. The formulation is defined as " + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "inline_equation", + "content": "\\frac{1}{\\mathcal{C}(x)}\\sum_{\\forall j}f(x_i,x_j)g(x_j)" + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "text", + "content": " denotes the input feature map and " + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "inline_equation", + "content": "f(\\cdot)" + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "text", + "content": " is a similarity function, e.g., cosine or Euclidean distance. " + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "inline_equation", + "content": "g(\\cdot)" + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "text", + "content": " computes a certain input representation, and " + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "inline_equation", + "content": "\\mathcal{C}(x)" + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "text", + "content": " is a normalization factor. By setting " + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "inline_equation", + "content": "f(\\cdot)" + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "text", + "content": " as the dot-product similarity and " + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "inline_equation", + "content": "\\mathcal{C}(x) = n" + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 46, + 331, + 289, + 489 + ], + "type": "text", + "content": " is the sequence length, we get an attention variant, named Scaling Attention (ScaleAttn). ScaleAttn is an extremely simple attention and only involves linear operations like multiplication and addition. ScaleAttn can be further reparameterized to accelerate computation1 as below:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 59, + 502, + 274, + 529 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 502, + 274, + 529 + ], + "spans": [ + { + "bbox": [ + 59, + 502, + 274, + 529 + ], + "type": "interline_equation", + "content": "\\mathrm {S c a l e A t t n} (Q, K, V) = \\frac {1}{n} (Q K ^ {T}) V = \\frac {Q}{\\sqrt {n}} (\\frac {K ^ {T}}{\\sqrt {n}} V).", + "image_path": "8c94367f387fc421e07e2fc367b2c3dff7c3601e68f49579523858d208fd261c.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 544, + 190, + 559 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 544, + 190, + 559 + ], + "spans": [ + { + "bbox": [ + 47, + 544, + 190, + 559 + ], + "type": "text", + "content": "2.2. Multi-Party Computation" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 566, + 287, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 566, + 287, + 676 + ], + "spans": [ + { + "bbox": [ + 46, + 566, + 287, + 676 + ], + "type": "text", + "content": "MPC [14] is a cryptographic technique that offers a promising solution to protect the privacy of both data and model during deep learning inference. Appendix B depicts the cryptographic primitives for MPC, including Secret Sharing, Oblivious Transfer and Garble Circuit. [14] proposes an efficient MPC protocol for addition and multiplication. [44] proposes efficient two-party computation protocols for various arithmetic operations and approximations for non-linear functions in DNN. For example, [44]" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 280, + 502, + 293 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 280, + 502, + 293 + ], + "spans": [ + { + "bbox": [ + 306, + 280, + 502, + 293 + ], + "type": "text", + "content": "approximates Softmax with ReLU Softmax, i.e.," + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 340, + 298, + 512, + 326 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 340, + 298, + 512, + 326 + ], + "spans": [ + { + "bbox": [ + 340, + 298, + 512, + 326 + ], + "type": "interline_equation", + "content": "\\operatorname {R e L U S o f t m a x} (x) = \\frac {\\operatorname {R e L U} (x _ {i})}{\\sum_ {i} \\operatorname {R e L U} (x _ {i}) + \\epsilon},", + "image_path": "5f50567f82fb9432d773d4276244ed0687cb9784d120c4053c7bf0d8f1829060.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 331, + 545, + 426 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 331, + 545, + 426 + ], + "spans": [ + { + "bbox": [ + 304, + 331, + 545, + 426 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 331, + 545, + 426 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 304, + 331, + 545, + 426 + ], + "type": "text", + "content": " is a very small value to avoid the zero denominator. ABY3 [43] is proposed to enable efficient conversion between different secret sharing schemes in three-party computation. Delphi [42] develops a hybrid MPC protocol and optimizes the network to explore the performance-accuracy trade-off. Iron [18] proposes a set of protocols to reduce the communication overhead of matrix-matrix multiplications (MatMuls), LayerNorm, etc for Transformer-based models." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 426, + 546, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 426, + 546, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 426, + 546, + 715 + ], + "type": "text", + "content": "Although MPC protocols have been improved significantly in recent years, DNN inference in MPC still suffers from intensive communication and latency overhead compared to the plaintext inference. To reduce the latency, different algorithms have been proposed to optimize convolutional NNs (CNNs) with a focus on ReLU. We compare the important characteristics of our methods with existing related work in Table 1. SNL [8] and DeepReduce [25] propose to remove ReLUs and linearize a subset of neurons selectively. SAFENet [37], Delphi [42], RRNet [48] and PolyMPCNet [47] replace ReLUs with polynomial functions that are more MPC-friendly via NAS for CNNs. Sphynx [7] further develops an MPC-friendly architecture search space for CNNs and leverages NAS to optimize the accuracy given different latency constraints. However, these works mainly focus on the ReLU counts in CNNs, and accelerating ViTs with latency consideration is still a challenge. MPCFormer [33] and THE-X [6] recently propose to replace Softmax with more MPC-friendly operations for BERT, but the network-level method incurs limited latency reduction and a large accuracy degradation. As shown in Table 1, our work proposes an MPC-aware NAS to explore a fined-grained heterogeneous attention optimization space, and further presents a GeLU linearization" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 47, + 693, + 287, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 693, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 47, + 693, + 287, + 712 + ], + "type": "text", + "content": "1In this work, we do not focus on computational overhead in MPC since communication dominates the overhead." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5054" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 64, + 91, + 530, + 198 + ], + "blocks": [ + { + "bbox": [ + 47, + 69, + 545, + 90 + ], + "lines": [ + { + "bbox": [ + 47, + 69, + 545, + 90 + ], + "spans": [ + { + "bbox": [ + 47, + 69, + 545, + 90 + ], + "type": "text", + "content": "Table 2. Top-1 accuracy and latency comparison of different attention variants on CIFAR-10. The rows in grey are attention variants with the lowest latency and the highest accuracy, respectively. We also show the properties and remaining operations of each variant." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 64, + 91, + 530, + 198 + ], + "lines": [ + { + "bbox": [ + 64, + 91, + 530, + 198 + ], + "spans": [ + { + "bbox": [ + 64, + 91, + 530, + 198 + ], + "type": "table", + "html": "
Attention VariantMonotonicityNon-negativityNormalizationExponentialMaxReciprocalAcc. (%)Lat. (s)
Softmax Attention [11]✓✓✓✓✓✓92.696.82
Linformer Attention [58]✓✓✓✓✓✓90.855.44
ReLU Attention✓✓✗✗✓✗failfail
ReLU6 Attention✓✓✗✗✓✗90.503.02
Sparsemax Attention [40]✓✓✗✗✓✗91.233.23
XNorm Attention [53]✓✗✗✗✗✓91.2413.25
Square Attention✗✓✗✗✗✗91.270.72
2Quad Attention [33]✗✓✓✗✗✓91.864.22
Scaling Attention (ScaleAttn) [59]✓✗✗✗✗✗91.520.66
ReLU Softmax Attention (RSAAttn) [44]✓✓✓✗✓✓92.315.32
", + "image_path": "5eb3ce17d4660ea1bc3780de17a38f1c1319b3cad996d1740e9bd38809eec1cf.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 50, + 214, + 286, + 324 + ], + "blocks": [ + { + "bbox": [ + 50, + 214, + 286, + 324 + ], + "lines": [ + { + "bbox": [ + 50, + 214, + 286, + 324 + ], + "spans": [ + { + "bbox": [ + 50, + 214, + 286, + 324 + ], + "type": "image", + "image_path": "47634366d0c7d64767a1c148d641e59259a3bb4fff777524082ae8e284452b38.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 327, + 288, + 371 + ], + "lines": [ + { + "bbox": [ + 46, + 327, + 288, + 371 + ], + "spans": [ + { + "bbox": [ + 46, + 327, + 288, + 371 + ], + "type": "text", + "content": "Figure 3. (a) Latency breakdown of a 4-head ViT with 256 hidden dimension and 65 tokens on CIFAR-10 dataset; (b) latency breakdown of Softmax. Both (a) and (b) consist of SEMI-2K (outside) and Cheetah (inside) protocols." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 392, + 209, + 403 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 392, + 209, + 403 + ], + "spans": [ + { + "bbox": [ + 47, + 392, + 209, + 403 + ], + "type": "text", + "content": "technique to reduce the latency of MLP." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 416, + 242, + 430 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 416, + 242, + 430 + ], + "spans": [ + { + "bbox": [ + 47, + 416, + 242, + 430 + ], + "type": "text", + "content": "3. Motivating Inspiration of MPCViT" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 437, + 287, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 437, + 287, + 498 + ], + "spans": [ + { + "bbox": [ + 46, + 437, + 287, + 498 + ], + "type": "text", + "content": "In this section, we breakdown Softmax for accuracy and efficiency evaluation and compare two ways of building MPC-friendly ViTs. The analysis serves as our motivation of proposing MPCViT, which features heterogeneous attention and NAS-based Pareto optimization." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 498, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 498, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 498, + 288, + 713 + ], + "type": "text", + "content": "Motivation 1: ViT latency bottleneck in MPC. In Figure 1, we profile the latency of a Transformer block with different number of heads and tokens. We now further dive into Softmax and evaluate its latency breakdown. We profile a 4-head ViT with 65 tokens and 256 hidden dimension assuming the WAN setting as defined in §5.1. We consider two widely used protocols, including SEMI-2K [9] and Cheetah [22]. From both Figure 1 and Figure 3, we make the following observations: 1) Softmax is the major latency bottleneck in most cases. The latency of GeLU and MatMuls also becomes non-negligible when the number of heads or tokens is small; 2) Softmax mainly involves three operations, including exponential, reciprocal and max. All of the operations are important for the latency overhead. Therefore, we are motivated to get rid of these expensive operations as many as possible, and we propose to first focus on optimizing the Softmax and only consider GeLU and MatMul when the number of heads or tokens is small." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 217, + 545, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 217, + 545, + 434 + ], + "spans": [ + { + "bbox": [ + 304, + 217, + 545, + 434 + ], + "type": "text", + "content": "Motivation 2: comparison of different attention variants. To reduce the latency of Softmax in the attention module, there are two different ways, i.e., 1) reducing the dimension of " + }, + { + "bbox": [ + 304, + 217, + 545, + 434 + ], + "type": "inline_equation", + "content": "QK^T" + }, + { + "bbox": [ + 304, + 217, + 545, + 434 + ], + "type": "text", + "content": " such as Linformer [58], which approximates " + }, + { + "bbox": [ + 304, + 217, + 545, + 434 + ], + "type": "inline_equation", + "content": "QK^T" + }, + { + "bbox": [ + 304, + 217, + 545, + 434 + ], + "type": "text", + "content": " with a low rank matrix; and 2) simplifying Softmax by replacing exponential, reciprocal or max with other operations. For the second method, while the possible activation variants can be abundant, we observe the following three important properties of Softmax, which helps us to select promising candidates: monotonicity, non-negativity, and normalized sum to 1. The first two properties are related to the exponential while the last one is achieved with reciprocal. We propose and evaluate the following variants, including ReLU, ReLU6, Sparsemax [40], XNorm [53], Square, Scaling [59], 2Quard [33], Linformer [58] and ReLU Softmax [44]. We define the attention with ReLU Softmax as RSAttn for short. The formulation of these attention variants is described in Appendix C." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 437, + 546, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 437, + 546, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 437, + 546, + 715 + ], + "type": "text", + "content": "To compare these attention variants, we train each model for 300 epochs on CIFAR-10 and compare the latency, accuracy, remaining operations, and how they satisfy the properties of Softmax in Table 2. We make the following observations: 1) Attention with more expensive operations can be more inefficient. For instance, 2Quad has an extra reciprocal compared with Square such that 2Quad suffers from a higher latency; 2) Linformer suffers from a high accuracy degradation (" + }, + { + "bbox": [ + 304, + 437, + 546, + 715 + ], + "type": "inline_equation", + "content": "\\sim 1.8\\%" + }, + { + "bbox": [ + 304, + 437, + 546, + 715 + ], + "type": "text", + "content": " compared with Softmax attention) as it significantly reduces the matrix dimensions such that the model learning capability is degraded, and the computation reduction of this optimization cannot benefit latency reduction a lot. Hence, the first method is not preferred; 3) ReLU Softmax and 2Quad achieve higher accuracy among other variants and we hypothesize this is because they both normalize the sum to 1, which is realized with reciprocal and also leads to relatively higher latency. ReLU Softmax is more preferred over Softmax and 2Quad due to its small approximation error and small accuracy degradation; 4) Scaling is equivalent to directly removing the Softmax. Although it is the fastest, directly linearizing all the Softmax leads to a large accuracy degradation; 5) it is interesting to notice that although XNorm attention has linear com" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5055" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 107 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 107 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 107 + ], + "type": "text", + "content": "putation, it incurs the highest latency because computing " + }, + { + "bbox": [ + 47, + 72, + 287, + 107 + ], + "type": "inline_equation", + "content": "\\ell 2" + }, + { + "bbox": [ + 47, + 72, + 287, + 107 + ], + "type": "text", + "content": "-norm involves both reciprocal and square root, both of which are expensive in MPC." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 108, + 286, + 239 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 108, + 286, + 239 + ], + "spans": [ + { + "bbox": [ + 46, + 108, + 286, + 239 + ], + "type": "text", + "content": "Motivation 3: Not all attentions are equally important. As observed in [5, 36, 41, 46, 54, 56], not all attentions are equally important and different layer prefers different attention type. For instance, [46] identifies the minor contribution of the early attention layers in recent ViTs, while [34] demonstrates the second head shows higher importance than other heads. Thus, the importance of attentions among different layers or even the attentions within the same layer can be different. It indicates we can safely replace the expensive Softmax or ReLU Softmax with the cheaper Scaling without compromising the network accuracy." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 239, + 286, + 264 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 239, + 286, + 264 + ], + "spans": [ + { + "bbox": [ + 47, + 239, + 286, + 264 + ], + "type": "text", + "content": "Remark The analysis above provides us with the following intuitions when designing an MPC-friendly ViT:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 268, + 286, + 387 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 54, + 268, + 286, + 304 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 268, + 286, + 304 + ], + "spans": [ + { + "bbox": [ + 54, + 268, + 286, + 304 + ], + "type": "text", + "content": "1) ReLU Softmax is more preferred over Softmax and more MPC-friendly, and Scaling has the highest inference efficiency;" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 310, + 286, + 346 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 310, + 286, + 346 + ], + "spans": [ + { + "bbox": [ + 53, + 310, + 286, + 346 + ], + "type": "text", + "content": "2) by selectively replacing the ReLU Softmax with the cheaper Scaling, it is possible to reduce the inference latency without compromising the inference accuracy;" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 352, + 286, + 387 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 352, + 286, + 387 + ], + "spans": [ + { + "bbox": [ + 53, + 352, + 286, + 387 + ], + "type": "text", + "content": "3) when the latency of GeLU and Softmax are comparable, we have an opportunity to further simplify GeLU along with Softmax." + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 47, + 394, + 238, + 407 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 394, + 238, + 407 + ], + "spans": [ + { + "bbox": [ + 47, + 394, + 238, + 407 + ], + "type": "text", + "content": "4. The Proposed MPCViT Algorithm" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 415, + 286, + 450 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 415, + 286, + 450 + ], + "spans": [ + { + "bbox": [ + 47, + 415, + 286, + 450 + ], + "type": "text", + "content": "In this section, we introduce MPCViT, which for the first time optimizes the ViT architecture with NAS-based algorithm for a fast private inference in MPC." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 456, + 216, + 468 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 456, + 216, + 468 + ], + "spans": [ + { + "bbox": [ + 47, + 456, + 216, + 468 + ], + "type": "text", + "content": "4.1. Overview of Optimization Flow" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 474, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 474, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 474, + 286, + 713 + ], + "type": "text", + "content": "Based on the motivations described above, we now describe our MPC-aware ViT optimization flow as shown in Figure 4. We propose to replace the Softmax with the accurate yet MPC-friendly ReLU Softmax in the ViT first and then, linearize the relatively \"unimportant\" ReLU Softmax with efficient Scaling. To find the \"unimportant\" ReLU Softmax, we first design a heterogeneous search space that includes both ReLU Softmax and Scaling attentions. Architecture parameters are defined to measure the importance of ReLU Softmax and enable the selection between the two attention variants with different structure granularities (§4.2). Then, we propose an MPC-aware differentiable NAS algorithm to learn the architecture parameters and model parameters simultaneously. We select between the attention variants based on the architecture parameters and the latency constraints (§4.3). In the last step, we retrain the ViT with heterogeneous attentions from scratch. We leverage knowledge distillation (KD) to improve the accuracy of the searched networks (§4.4). Appendix D depicts the complete algorithm flow of MPCViT." + } + ] + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 309, + 72, + 544, + 205 + ], + "blocks": [ + { + "bbox": [ + 309, + 72, + 544, + 205 + ], + "lines": [ + { + "bbox": [ + 309, + 72, + 544, + 205 + ], + "spans": [ + { + "bbox": [ + 309, + 72, + 544, + 205 + ], + "type": "image", + "image_path": "698fe7e2af04aca536d4b0f02fcfcdc169a001e5e04c3922111a38767c9a25e7.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 324, + 206, + 523, + 218 + ], + "lines": [ + { + "bbox": [ + 324, + 206, + 523, + 218 + ], + "spans": [ + { + "bbox": [ + 324, + 206, + 523, + 218 + ], + "type": "text", + "content": "Figure 4. Overview of our proposed MPCViT pipeline." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 235, + 509, + 248 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 235, + 509, + 248 + ], + "spans": [ + { + "bbox": [ + 306, + 235, + 509, + 248 + ], + "type": "text", + "content": "4.2. Heterogeneous Attention Search Space" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 254, + 545, + 301 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 254, + 545, + 301 + ], + "spans": [ + { + "bbox": [ + 305, + 254, + 545, + 301 + ], + "type": "text", + "content": "Our heterogeneous search space combines two candidate attention variants, i.e., MPC-efficient ScaleAttn and high-accuracy RSAAttn and has the following three different structural granularities as shown in Figure 5:" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 317, + 306, + 545, + 427 + ], + "type": "list", + "angle": 0, + "index": 18, + "blocks": [ + { + "bbox": [ + 317, + 306, + 545, + 354 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 306, + 545, + 354 + ], + "spans": [ + { + "bbox": [ + 317, + 306, + 545, + 354 + ], + "type": "text", + "content": "- Layer-wise search space is coarse-grained, with each layer using either ScaleAttn or RSAattn. The total number of possible architectures in the search space can be limited, especially for shallow ViT models." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 317, + 361, + 544, + 384 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 361, + 544, + 384 + ], + "spans": [ + { + "bbox": [ + 317, + 361, + 544, + 384 + ], + "type": "text", + "content": "- Head-wise search space selects ScaleAttn or RSAAttn for each attention head of each layer." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 317, + 392, + 545, + 427 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 392, + 545, + 427 + ], + "spans": [ + { + "bbox": [ + 317, + 392, + 545, + 427 + ], + "type": "text", + "content": "- Row-wise search space (i.e., token-wise) is the most fine-grained and mixes the two attention variants along each row of the attention map." + } + ] + } + ], + "index": 17 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 305, + 433, + 544, + 480 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 433, + 544, + 480 + ], + "spans": [ + { + "bbox": [ + 305, + 433, + 544, + 480 + ], + "type": "text", + "content": "Though the search spaces have different granularities, they share very similar NAS formulation. In the rest of the explanation, we will use the head-wise search space as an example to explain our algorithm." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 487, + 479, + 498 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 487, + 479, + 498 + ], + "spans": [ + { + "bbox": [ + 306, + 487, + 479, + 498 + ], + "type": "text", + "content": "4.3. MPC-Aware Differentiable NAS" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 505, + 545, + 588 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 505, + 545, + 588 + ], + "spans": [ + { + "bbox": [ + 304, + 505, + 545, + 588 + ], + "type": "text", + "content": "Many research efforts have been made to NAS including reinforcement learning method (RL) [17, 24, 57], however, RL-based NAS requires significant overhead during searching. Recent years, [10, 27, 55, 61] explore hardware-aware NAS algorithms to make model fit the rigorous hardware requirement. For private ViT inference, we also need a NAS algorithm that takes MPC conditions into consideration." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 589, + 544, + 624 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 589, + 544, + 624 + ], + "spans": [ + { + "bbox": [ + 304, + 589, + 544, + 624 + ], + "type": "text", + "content": "Given the heterogeneous attention search space, we now introduce our simple yet effective MPC-aware differentiable NAS algorithm." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 624, + 545, + 684 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 624, + 545, + 684 + ], + "spans": [ + { + "bbox": [ + 304, + 624, + 545, + 684 + ], + "type": "text", + "content": "Search formulation. Inspired by [5], we introduce an architecture parameter " + }, + { + "bbox": [ + 304, + 624, + 545, + 684 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 624, + 545, + 684 + ], + "type": "text", + "content": " (" + }, + { + "bbox": [ + 304, + 624, + 545, + 684 + ], + "type": "inline_equation", + "content": "0 \\leq \\alpha \\leq 1" + }, + { + "bbox": [ + 304, + 624, + 545, + 684 + ], + "type": "text", + "content": ") for each head, which is an auxiliary learnable variable that helps to choose between RSAAtt and ScaleAttn. Then, each head implements the computation below:" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 306, + 689, + 547, + 717 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 547, + 717 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 547, + 717 + ], + "type": "interline_equation", + "content": "\\alpha \\cdot \\operatorname {R e L U S o f t m a x} \\left(\\frac {Q K ^ {T}}{\\sqrt {d _ {k}}}\\right) V + (1 - \\alpha) \\cdot \\frac {\\operatorname {S c a l e A t t n} (Q , K , V)}{\\sqrt {d _ {k}}}.", + "image_path": "c1b2bb2547783d85b69379492f255e7946b30566dd41d3a833185ac262c34754.jpg" + } + ] + } + ], + "index": 24 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5056" + } + ] + } + ], + "index": 25 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 70, + 286, + 185 + ], + "blocks": [ + { + "bbox": [ + 49, + 70, + 286, + 185 + ], + "lines": [ + { + "bbox": [ + 49, + 70, + 286, + 185 + ], + "spans": [ + { + "bbox": [ + 49, + 70, + 286, + 185 + ], + "type": "image", + "image_path": "ffe906ef0c4c3f9cf186366397d0781739333ecc01c993cf203d5dfc4821633a.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 187, + 287, + 253 + ], + "lines": [ + { + "bbox": [ + 46, + 187, + 287, + 253 + ], + "spans": [ + { + "bbox": [ + 46, + 187, + 287, + 253 + ], + "type": "text", + "content": "Figure 5. An illustration of our proposed search space with different structure granularities: (a) layer-wise search space with the size of " + }, + { + "bbox": [ + 46, + 187, + 287, + 253 + ], + "type": "inline_equation", + "content": "2^{\\# \\text{layers}}" + }, + { + "bbox": [ + 46, + 187, + 287, + 253 + ], + "type": "text", + "content": "; (b) head-wise search space with the size of " + }, + { + "bbox": [ + 46, + 187, + 287, + 253 + ], + "type": "inline_equation", + "content": "2^{\\# \\text{layers} \\times \\# \\text{heads}}" + }, + { + "bbox": [ + 46, + 187, + 287, + 253 + ], + "type": "text", + "content": " and; (c) row-wise search space with the size of " + }, + { + "bbox": [ + 46, + 187, + 287, + 253 + ], + "type": "inline_equation", + "content": "2^{\\# \\text{layers} \\times \\# \\text{heads} \\times \\# \\text{tokens}}" + }, + { + "bbox": [ + 46, + 187, + 287, + 253 + ], + "type": "text", + "content": ". The blocks in blue represent RSAAttn and the blocks in grey represent ScaleAttn." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 273, + 287, + 297 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 273, + 287, + 297 + ], + "spans": [ + { + "bbox": [ + 47, + 273, + 287, + 297 + ], + "type": "text", + "content": "Note that we also add " + }, + { + "bbox": [ + 47, + 273, + 287, + 297 + ], + "type": "inline_equation", + "content": "\\frac{1}{\\sqrt{d_k}}" + }, + { + "bbox": [ + 47, + 273, + 287, + 297 + ], + "type": "text", + "content": " for ScaleAttn to make the search process more stable and robust." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 298, + 287, + 382 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 298, + 287, + 382 + ], + "spans": [ + { + "bbox": [ + 46, + 298, + 287, + 382 + ], + "type": "text", + "content": "Search objective function. We aim at training ViTs with high accuracy but as few RSAattn as possible. We introduce " + }, + { + "bbox": [ + 46, + 298, + 287, + 382 + ], + "type": "inline_equation", + "content": "\\ell 1" + }, + { + "bbox": [ + 46, + 298, + 287, + 382 + ], + "type": "text", + "content": "-penalty into the objective function and formulate the NAS as a one-level optimization problem. To take MPC overhead into consideration, we incorporate realistic inference latency constraints into objective function to construct the MPC-aware NAS algorithm as" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 96, + 392, + 237, + 406 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 96, + 392, + 237, + 406 + ], + "spans": [ + { + "bbox": [ + 96, + 392, + 237, + 406 + ], + "type": "interline_equation", + "content": "\\mathrm {C o s t} (\\alpha_ {i j}) = \\alpha_ {i j} \\cdot \\mathrm {L a t (A T T N} _ {i j}),", + "image_path": "6458459ca0d155331765a1b9d2029b1a03a9fd2dfd5671c7290a7cba693bbbfb.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 70, + 408, + 264, + 441 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 408, + 264, + 441 + ], + "spans": [ + { + "bbox": [ + 70, + 408, + 264, + 441 + ], + "type": "interline_equation", + "content": "\\min _ {\\theta , \\alpha} \\ell (f _ {\\theta , \\alpha} (x), y) + \\lambda \\cdot (\\sum_ {i = 1} ^ {L} \\sum_ {j = 1} ^ {N} \\| \\operatorname {C o s t} (\\alpha_ {i j}) \\| _ {1}),", + "image_path": "ce98a05a1e49e79fd649e733eb876fed87c1c544259a90095cf5b792788dba46.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "spans": [ + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "y" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": " are the input-label pairs, " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "\\ell(\\cdot)" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": " is the loss function, " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": " is a hyper-parameter to control the weight of inference overhead, " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": " is the number of heads in one layer, and " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": " is the number of layers. " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "\\| \\cdot \\|_1" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": " means " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "\\ell 1" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": "-norm, and " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "\\mathrm{ATTN}_{ij}" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": " means the candidate attention of " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": "-th layer and " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": "-th head. We initialize " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": " for each head to 1.0 and jointly optimize the network parameter " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": " and architecture parameter " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": " during searching. Note that our differentiable algorithm computes the gradients of " + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 450, + 287, + 569 + ], + "type": "text", + "content": " for all the attention heads across different layers in ViT simultaneously." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "content": "Architecture parameter binarization. After the network searching, we obtain " + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "content": " for each attention head in all layers. To select either RSAattn or ScaleAttn for each head, we binarize " + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "content": " based on the following rule: we use the top-" + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "content": " rule according to the ratio of RSAattn budgeet " + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mu" + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "content": ", which is defined as " + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\# \\text{RSAattn} / \\# \\text{Heads}" + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "content": ". Specifically, we first find the " + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mu L N" + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "content": "-th largest " + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "content": ", denoted as " + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\alpha^{*}" + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "content": ", and then we binarize " + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "content": " for each attention head following " + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathbb{1}(\\alpha \\geq \\alpha^{*})" + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "content": ". Our proposed search method does not need to train candidate networks, but only needs to train once and then select, which accelerates our search process. Now, we obtain a heterogeneous ViT, and by changing " + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mu" + }, + { + "bbox": [ + 46, + 570, + 287, + 713 + ], + "type": "text", + "content": ", we can obtain a family of" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 307, + 72, + 545, + 168 + ], + "blocks": [ + { + "bbox": [ + 307, + 72, + 545, + 168 + ], + "lines": [ + { + "bbox": [ + 307, + 72, + 545, + 168 + ], + "spans": [ + { + "bbox": [ + 307, + 72, + 545, + 168 + ], + "type": "image", + "image_path": "af21e0dc47712bcf343889eb7b92c595f0a6d63eb1b0d8a92516e29847a27dc0.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 170, + 545, + 190 + ], + "lines": [ + { + "bbox": [ + 305, + 170, + 545, + 190 + ], + "spans": [ + { + "bbox": [ + 305, + 170, + 545, + 190 + ], + "type": "text", + "content": "Figure 6. MPCViT+: The optimization of our proposed GeLU linearization and linear fusion for the MLP block." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 210, + 520, + 222 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 210, + 520, + 222 + ], + "spans": [ + { + "bbox": [ + 306, + 210, + 520, + 222 + ], + "type": "text", + "content": "ViTs with different accuracy and efficiency trade-off." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 231, + 545, + 243 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 231, + 545, + 243 + ], + "spans": [ + { + "bbox": [ + 306, + 231, + 545, + 243 + ], + "type": "text", + "content": "4.4. Train the Searched ViT for Better Performance" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 249, + 545, + 308 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 249, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 304, + 249, + 545, + 308 + ], + "type": "text", + "content": "After binarization, RSAattn with a small " + }, + { + "bbox": [ + 304, + 249, + 545, + 308 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 249, + 545, + 308 + ], + "type": "text", + "content": " are replaced with ScaleAttn. We find that directly training a heterogeneous ViT results in an accuracy drop. So, how to effectively train the heterogeneous ViT and restore the model accuracy is an important question for us." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "spans": [ + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "text", + "content": "Token-wise feature-based KD. KD [21] is a powerful tool for a student network to learn from a teacher network, which is usually larger and more complex with a higher learning capacity. To improve the accuracy of MPCViT, we leverage token-wise feature-based self-distillation along with a logits-based KD, which uses the baseline ViT as the teacher network while other larger networks can be easily plugged in and used in our framework. For the feature-based KD, we take the output features of the last ViT layer from both the student and the teacher networks and compute the " + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "inline_equation", + "content": "\\ell 2" + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "text", + "content": "-distance, denoted as " + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\text {feature }}" + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "text", + "content": ". We also use KL-divergence loss " + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{KL}" + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "text", + "content": " for the logits-based KD, denoted as " + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\text {logits }}" + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "text", + "content": ". Combining distillation loss with the task-specific cross-entropy (CE) loss " + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{CE}" + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "text", + "content": ", we obtain the final training objective under a distillation temperature " + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "inline_equation", + "content": "\\mathcal{T}" + }, + { + "bbox": [ + 304, + 309, + 546, + 489 + ], + "type": "text", + "content": " as follows:" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 309, + 498, + 542, + 536 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 498, + 542, + 536 + ], + "spans": [ + { + "bbox": [ + 309, + 498, + 542, + 536 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {L} _ {\\text {t r a i n}} = \\chi \\mathcal {L} _ {C E} + \\beta \\mathcal {L} _ {\\text {l o g i t s}} + \\gamma \\mathcal {L} _ {\\text {f e a t u r e}} \\\\ = \\chi \\mathcal {L} _ {C E} + \\beta \\mathcal {L} _ {K L} (\\sigma (\\frac {z _ {s}}{\\mathcal {T}}), \\sigma (\\frac {z _ {t}}{\\mathcal {T}})) + \\gamma \\| z _ {s} - z _ {t} \\| _ {2}, \\\\ \\end{array}", + "image_path": "d50f21df601a881d28e64d9d5f93da85aea30d57bee5f7871d727972f910669f.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "spans": [ + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "type": "inline_equation", + "content": "\\chi, \\beta" + }, + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "type": "text", + "content": " are training hyper-parameters to balance different loss functions in the training objective, " + }, + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "type": "inline_equation", + "content": "z_{s}" + }, + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "type": "inline_equation", + "content": "z_{t}" + }, + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "type": "text", + "content": " are feature maps from student and teacher, and " + }, + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 304, + 543, + 545, + 615 + ], + "type": "text", + "content": " is Softmax. This self-distillation requires no extra model and only introduces negligible training cost, and has no influence on inference latency or communication overhead in MPC." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 623, + 537, + 635 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 623, + 537, + 635 + ], + "spans": [ + { + "bbox": [ + 306, + 623, + 537, + 635 + ], + "type": "text", + "content": "4.5. MPCViT+: Support for GeLU Linearization" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 641, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 545, + 713 + ], + "type": "text", + "content": "The above design of MPCViT leverages NAS algorithm to build the efficient yet effective attention mechanism. Besides attention, in MLP blocks, non-linear GeLU also impacts the communication cost in some protocols, e.g., Cheetah when the number of heads or tokens is small. And two linear layers near GeLU are also costly because" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5057" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "content": "the inverted-bottleneck structure of MLP leads to high-dimensional MatMul, which is shown in Figure 1 and Figure 3(a). To further improve the efficiency of ViTs, we propose an extended version called MPCViT+. Specifically, MPCViT+ searches and removes relatively \"unimportant\" GeLUs. Given architecture parameter " + }, + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "content": " for GeLU, the NAS algorithm is similar to the attention optimization:" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 97, + 165, + 237, + 178 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 97, + 165, + 237, + 178 + ], + "spans": [ + { + "bbox": [ + 97, + 165, + 237, + 178 + ], + "type": "interline_equation", + "content": "(\\beta \\cdot \\operatorname {G e L U} (x) + (1 - \\beta) \\cdot x) \\cdot \\mathscr {W}.", + "image_path": "c4de4fe2c000ba28a543c3dd03f898e3917b719fb6a0668cdebb538f155c757d.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 186, + 287, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 186, + 287, + 228 + ], + "spans": [ + { + "bbox": [ + 47, + 186, + 287, + 228 + ], + "type": "text", + "content": "The architecture parameters " + }, + { + "bbox": [ + 47, + 186, + 287, + 228 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 47, + 186, + 287, + 228 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 186, + 287, + 228 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 47, + 186, + 287, + 228 + ], + "type": "text", + "content": " are jointly learnt during the search, thus the NAS loss is defined along with the classification loss " + }, + { + "bbox": [ + 47, + 186, + 287, + 228 + ], + "type": "inline_equation", + "content": "\\min_{\\theta ,\\alpha ,\\beta}\\ell (f_{\\theta ,\\alpha ,\\beta}(x),y)" + }, + { + "bbox": [ + 47, + 186, + 287, + 228 + ], + "type": "text", + "content": " .." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 105, + 237, + 230, + 251 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 105, + 237, + 230, + 251 + ], + "spans": [ + { + "bbox": [ + 105, + 237, + 230, + 251 + ], + "type": "interline_equation", + "content": "\\operatorname {C o s t} \\left(\\beta_ {i j}\\right) = \\beta_ {i j} \\cdot \\operatorname {L a t} \\left(\\operatorname {A c t} _ {i j}\\right),", + "image_path": "16f11be87371f3cdc560c471f3c46be5de255ee35bc801ecf2920ca9d0543fcf.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 51, + 253, + 282, + 286 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 253, + 282, + 286 + ], + "spans": [ + { + "bbox": [ + 51, + 253, + 282, + 286 + ], + "type": "interline_equation", + "content": "\\lambda \\cdot (\\sum_ {i = 1} ^ {L} \\sum_ {j = 1} ^ {N} \\| \\operatorname {C o s t} \\left(\\alpha_ {i j}\\right) \\| _ {1}) + \\eta \\cdot (\\sum_ {i = 1} ^ {L} \\sum_ {j = 1} ^ {T} \\| \\operatorname {C o s t} \\left(\\beta_ {i j}\\right) \\| _ {1}),", + "image_path": "7d78b886e63ab7485439ea9d08f6c6bc45807108afaf1f47be55a35a9305f03d.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "spans": [ + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "text", + "content": "here, we take token-wise linearization as an example, and " + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "inline_equation", + "content": "\\mathrm{Lat}(\\mathrm{Act}_{\\mathrm{ij}})" + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "text", + "content": " denotes the latency of either GeLU or identity of " + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "text", + "content": "-th layer and " + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "text", + "content": "-th token, " + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "text", + "content": " denotes the number of tokens in each layer. We can consider the balance between " + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "inline_equation", + "content": "\\eta" + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "text", + "content": " through the private inference latency: " + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "inline_equation", + "content": "\\frac{\\lambda}{\\eta} = \\frac{\\mathrm{Lat}(\\mathrm{ATTN})}{\\mathrm{Lat}(\\mathrm{GELU})}" + }, + { + "bbox": [ + 47, + 294, + 287, + 356 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "spans": [ + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "content": "Fuse two linear layers together. After GeLU linearization, we observe an opportunity for further latency reduction. As shown in Figure 6, we fuse the linear layer before and after GeLU of a certain token, which reduces the communication associated with the MLP. Denote the input of a MLP block of " + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "content": "-th layer as " + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "inline_equation", + "content": "X^{(i)} \\in \\mathbb{R}^{B \\times H \\times W \\times C}" + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "content": ", the linear layers as " + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mathcal{W}_1^{(i)} \\in \\mathbb{R}^{C \\times K}" + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mathcal{W}_2^{(i)} \\in \\mathbb{R}^{K \\times C}" + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "content": ", the output of MLP as " + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "inline_equation", + "content": "X^{(i+1)} \\in \\mathbb{R}^{B \\times H \\times W \\times C}" + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "content": ". The input dimension of GeLU is " + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "inline_equation", + "content": "B \\times H \\times W \\times K" + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "inline_equation", + "content": "C, K" + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "content": " are channel numbers of linear layers. Note that we generally set the ratio of MLP (i.e., " + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\frac{K}{C}" + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "content": ") to 2 or 4 in ViT models. The linearized MLP can be formulated as " + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "inline_equation", + "content": "X^{(i+1)} = (X^{(i)}\\mathcal{W}_1^{(i)})\\mathcal{W}_2^{(i)} = X^{(i)}(\\mathcal{W}_1^{(i)}\\mathcal{W}_2^{(i)})" + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "content": ". In this way, " + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mathcal{W}_1^{(i)}\\mathcal{W}_2^{(i)}" + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "content": " is fused into " + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mathcal{W}_f^{(i)} \\in \\mathbb{R}^{C \\times C}" + }, + { + "bbox": [ + 46, + 357, + 287, + 552 + ], + "type": "text", + "content": ", which optimizes two high-dimensional MatMuls to only a single low-dimensional MatMul, further reducing the latency of MLP." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 552, + 287, + 612 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 552, + 287, + 612 + ], + "spans": [ + { + "bbox": [ + 46, + 552, + 287, + 612 + ], + "type": "text", + "content": "Adding additional activations. After GeLU removal and linear fusion, there is no non-linearity in these tokens. To boost the accuracy, we additionally add a non-linear function after the fused linear positions. Here, we choose to add ReLU which incurs a cheaper cost than GeLU." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 621, + 128, + 635 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 621, + 128, + 635 + ], + "spans": [ + { + "bbox": [ + 47, + 621, + 128, + 635 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 641, + 163, + 654 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 641, + 163, + 654 + ], + "spans": [ + { + "bbox": [ + 47, + 641, + 163, + 654 + ], + "type": "text", + "content": "5.1. Experimental Setup" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 659, + 287, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 659, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 47, + 659, + 287, + 696 + ], + "type": "text", + "content": "Experimental and MPC settings. In our experiments, we leverage the SecretFlow (SPU [39] V0.3.1b0)2 framework for private inference, which is popular for privacy-" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 72, + 545, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 545, + 156 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 545, + 156 + ], + "type": "text", + "content": "preserving deep learning. We adopt the SEMI-2K [9] protocol, which is a semi-honest two-party computation protocol3. We follow Cheetah [22] and use the WAN mode for communication. Specifically, the communication bandwidth between the cloud instances is set to 44 MBps and the round-trip time is set to 40ms. Our experiments are evaluated on an Intel Xeon CPU@2.40 GHz with 62 GB RAM." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 156, + 546, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 156, + 546, + 251 + ], + "spans": [ + { + "bbox": [ + 305, + 156, + 546, + 251 + ], + "type": "text", + "content": "Model architectures and datasets. Many researches have studied training ViTs on small datasets [12, 19, 23, 32, 35]. We consider two ViT architectures on three commonly used datasets following [19]. For the CIFAR-10/100 dataset, we set the ViT depth, # heads, hidden dimension, and patch size to 7, 4, 256, and 4, respectively. For TinyImageNet dataset, we set the ViT depth, # heads, hidden dimension, and patch size to 9, 12, 192, and 4, respectively." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 251, + 545, + 299 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 251, + 545, + 299 + ], + "spans": [ + { + "bbox": [ + 305, + 251, + 545, + 299 + ], + "type": "text", + "content": "Searching settings. We run the NAS algorithm for 300 epochs with AdamW optimizer and a cosine learning rate across three datasets. We set " + }, + { + "bbox": [ + 305, + 251, + 545, + 299 + ], + "type": "inline_equation", + "content": "\\epsilon = 10^{-8}" + }, + { + "bbox": [ + 305, + 251, + 545, + 299 + ], + "type": "text", + "content": " to avoid the zero denominator in RSAatt, and " + }, + { + "bbox": [ + 305, + 251, + 545, + 299 + ], + "type": "inline_equation", + "content": "\\lambda = 10^{-5}" + }, + { + "bbox": [ + 305, + 251, + 545, + 299 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 300, + 545, + 372 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 300, + 545, + 372 + ], + "spans": [ + { + "bbox": [ + 305, + 300, + 545, + 372 + ], + "type": "text", + "content": "Training settings. Following [19], we train the searched heterogeneous ViTs for 600 epochs on CIFAR-10/100 and 300 epochs on Tiny/ImageNet. We leverage data augmentations as [19]. For KD, we set the temperature " + }, + { + "bbox": [ + 305, + 300, + 545, + 372 + ], + "type": "inline_equation", + "content": "\\mathcal{T}" + }, + { + "bbox": [ + 305, + 300, + 545, + 372 + ], + "type": "text", + "content": " to 1, and set " + }, + { + "bbox": [ + 305, + 300, + 545, + 372 + ], + "type": "inline_equation", + "content": "\\chi, \\beta, \\gamma" + }, + { + "bbox": [ + 305, + 300, + 545, + 372 + ], + "type": "text", + "content": " to 1 as well. To explore the trade-off between inference accuracy and latency, we set " + }, + { + "bbox": [ + 305, + 300, + 545, + 372 + ], + "type": "inline_equation", + "content": "\\mu" + }, + { + "bbox": [ + 305, + 300, + 545, + 372 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 305, + 300, + 545, + 372 + ], + "type": "inline_equation", + "content": "\\{0.1, 0.3, 0.5, 0.7\\}" + }, + { + "bbox": [ + 305, + 300, + 545, + 372 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 378, + 545, + 391 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 378, + 545, + 391 + ], + "spans": [ + { + "bbox": [ + 306, + 378, + 545, + 391 + ], + "type": "text", + "content": "5.2. Comparison with Prior-Art Efficient Attentions" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 396, + 545, + 504 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 396, + 545, + 504 + ], + "spans": [ + { + "bbox": [ + 305, + 396, + 545, + 504 + ], + "type": "text", + "content": "Baselines. We compare MPCViT with prior-art models on the inference accuracy and efficiency. We compare with MPCFormer [33], Linformer [58, 60], THE-X [6] and ViT variants in Table 2. Linformer is studied in [60] as an efficient Transformer variant for MPC and the compression rate of attention dimension is also defined as " + }, + { + "bbox": [ + 305, + 396, + 545, + 504 + ], + "type": "inline_equation", + "content": "\\mu" + }, + { + "bbox": [ + 305, + 396, + 545, + 504 + ], + "type": "text", + "content": ". For networks compared with MPCViT, we only modify attention layer and keep MLP unchanged as the baseline ViT. For " + }, + { + "bbox": [ + 305, + 396, + 545, + 504 + ], + "type": "inline_equation", + "content": "\\mathrm{MPCViT^{+}}" + }, + { + "bbox": [ + 305, + 396, + 545, + 504 + ], + "type": "text", + "content": ", we optimize attention and MLP simultaneously." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 305, + 505, + 545, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 505, + 545, + 552 + ], + "spans": [ + { + "bbox": [ + 305, + 505, + 545, + 552 + ], + "type": "text", + "content": "Results and analysis. The main results are shown in Figure 7, where we report top-1 accuracy across three datasets and the network inference latency. The main findings are as follows:" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 312, + 559, + 545, + 687 + ], + "type": "list", + "angle": 0, + "index": 20, + "blocks": [ + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "spans": [ + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "text", + "content": "1) MPCViT outperforms prior-art methods. Without KD, on Tiny-ImageNet, MPCViT with " + }, + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "inline_equation", + "content": "\\mu = 0.1" + }, + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "text", + "content": " outperforms Linformer with " + }, + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "inline_equation", + "content": "\\mu = 0.7" + }, + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "text", + "content": " by " + }, + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "inline_equation", + "content": "0.57\\%" + }, + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "text", + "content": " better accuracy with " + }, + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "inline_equation", + "content": "4.9\\times" + }, + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "text", + "content": " latency reduction; Compared with THE-X, MPCViT achieve " + }, + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "inline_equation", + "content": "3.6\\%" + }, + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "text", + "content": " accuracy improvement with " + }, + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "inline_equation", + "content": "1.9\\times" + }, + { + "bbox": [ + 313, + 559, + 545, + 631 + ], + "type": "text", + "content": " latency reduction;" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "spans": [ + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "type": "text", + "content": "2) with proper KD, MPCViT even achieves " + }, + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "type": "inline_equation", + "content": "1.9\\%" + }, + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "type": "inline_equation", + "content": "1.3\\%" + }, + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "type": "text", + "content": " better accuracy with " + }, + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "type": "inline_equation", + "content": "6.2 \\times" + }, + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "type": "inline_equation", + "content": "2.9 \\times" + }, + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "type": "text", + "content": " latency reduction with " + }, + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "type": "inline_equation", + "content": "\\mu = 0.1" + }, + { + "bbox": [ + 312, + 638, + 545, + 687 + ], + "type": "text", + "content": " and 0.3, compared with baseline ViT and MPCFormer on Tiny-ImageNet, respectively;" + } + ] + } + ], + "index": 19 + } + ], + "sub_type": "text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 306, + 693, + 545, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 693, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 693, + 545, + 713 + ], + "type": "text", + "content": "3 Although the actual latency of each operator may be different for different MPC protocols, our proposed algorithm can be generally applied." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 57, + 702, + 257, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 702, + 257, + 712 + ], + "spans": [ + { + "bbox": [ + 57, + 702, + 257, + 712 + ], + "type": "text", + "content": "2https://github.com/secretflow/secretflow" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5058" + } + ] + } + ], + "index": 23 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 62, + 71, + 218, + 200 + ], + "blocks": [ + { + "bbox": [ + 62, + 71, + 218, + 200 + ], + "lines": [ + { + "bbox": [ + 62, + 71, + 218, + 200 + ], + "spans": [ + { + "bbox": [ + 62, + 71, + 218, + 200 + ], + "type": "image", + "image_path": "f67c43023e97fa720a08debae52b104d9347a318e8d586b96fc1a95b85c7975d.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 173, + 201, + 442, + 208 + ], + "lines": [ + { + "bbox": [ + 173, + 201, + 442, + 208 + ], + "spans": [ + { + "bbox": [ + 173, + 201, + 442, + 208 + ], + "type": "text", + "content": "- MPCViT w/o KD (ours) - MPCViT w/ KD (ours) Linformer - ReLU Softmax ViT - ScaleAttn ViT - THE-X" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_footnote" + }, + { + "bbox": [ + 113, + 226, + 478, + 238 + ], + "lines": [ + { + "bbox": [ + 113, + 226, + 478, + 238 + ], + "spans": [ + { + "bbox": [ + 113, + 226, + 478, + 238 + ], + "type": "text", + "content": "Figure 7. Top-1 Accuracy and inference latency comparison with baseline ViTs across three datasets." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 219, + 72, + 375, + 199 + ], + "blocks": [ + { + "bbox": [ + 219, + 72, + 375, + 199 + ], + "lines": [ + { + "bbox": [ + 219, + 72, + 375, + 199 + ], + "spans": [ + { + "bbox": [ + 219, + 72, + 375, + 199 + ], + "type": "image", + "image_path": "b40f7df352253d606c6384dc36b32dcbf74e255e9b8ee633040552c1d93a1948.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 186, + 211, + 427, + 219 + ], + "lines": [ + { + "bbox": [ + 186, + 211, + 427, + 219 + ], + "spans": [ + { + "bbox": [ + 186, + 211, + 427, + 219 + ], + "type": "text", + "content": "Softmax-ScaleAttn ViT Softmax ViT MPCViT w/ Per-layer Search MPCFormer w/KD MPFCorner w/o KD" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_footnote" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 376, + 72, + 533, + 199 + ], + "blocks": [ + { + "bbox": [ + 376, + 72, + 533, + 199 + ], + "lines": [ + { + "bbox": [ + 376, + 72, + 533, + 199 + ], + "spans": [ + { + "bbox": [ + 376, + 72, + 533, + 199 + ], + "type": "image", + "image_path": "f88ff4d0affc061ab1047c92c2fb697346fc1857b428795201ce1bbbd2d40afa.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 48, + 256, + 287, + 351 + ], + "blocks": [ + { + "bbox": [ + 48, + 256, + 287, + 351 + ], + "lines": [ + { + "bbox": [ + 48, + 256, + 287, + 351 + ], + "spans": [ + { + "bbox": [ + 48, + 256, + 287, + 351 + ], + "type": "image", + "image_path": "b4c2300e2cf1e73818bfec01f0fed8f8961791a2ceed4369c4c5720e689ea02c.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 354, + 287, + 375 + ], + "lines": [ + { + "bbox": [ + 47, + 354, + 287, + 375 + ], + "spans": [ + { + "bbox": [ + 47, + 354, + 287, + 375 + ], + "type": "text", + "content": "Figure 8. Latency and communication cost comparison of different layers in the 9-layer 12-head ViT with " + }, + { + "bbox": [ + 47, + 354, + 287, + 375 + ], + "type": "inline_equation", + "content": "\\mu = 0.5" + }, + { + "bbox": [ + 47, + 354, + 287, + 375 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 383, + 287, + 431 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 383, + 287, + 431 + ], + "spans": [ + { + "bbox": [ + 53, + 383, + 287, + 431 + ], + "type": "text", + "content": "3) we mix Softmax attention and ScaleAttn. Although it has a slightly higher accuracy in plaintext inference, it incurs at least " + }, + { + "bbox": [ + 53, + 383, + 287, + 431 + ], + "type": "inline_equation", + "content": "1.4 \\times" + }, + { + "bbox": [ + 53, + 383, + 287, + 431 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 53, + 383, + 287, + 431 + ], + "type": "inline_equation", + "content": "1.2 \\times" + }, + { + "bbox": [ + 53, + 383, + 287, + 431 + ], + "type": "text", + "content": " latency on CIFAR-10/100 and Tiny/ImageNet compared with MPCViT." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 437, + 287, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 437, + 287, + 521 + ], + "spans": [ + { + "bbox": [ + 46, + 437, + 287, + 521 + ], + "type": "text", + "content": "We visualize the latency and communication cost comparison of Softmax ViT, ReLU Softmax ViT, and MPCViT in Figure 8. We can observe the latency changes proportionally with the communication. Also, we observe for MPCViT, RSAattn in middle layers (e.g., layer 2 to layer 5) tend to be preserved while RSAattn in early and final layers are likely to be replaced with ScaleAttn." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 526, + 255, + 539 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 526, + 255, + 539 + ], + "spans": [ + { + "bbox": [ + 47, + 526, + 255, + 539 + ], + "type": "text", + "content": "5.3. Comparison on Structure Granularities" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 544, + 287, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 544, + 287, + 665 + ], + "spans": [ + { + "bbox": [ + 46, + 544, + 287, + 665 + ], + "type": "text", + "content": "The choice of search space is important for MPCViT, so we compare different structure granularities of search space proposed in §4.2. We use the CIFAR-10 dataset for the comparison. As shown in Table 3, the head-wise search space achieves the best accuracy. We hypothesize although rowwise structure leads to the largest search space, such a fine-grained search space may introduce difficulties in NAS, and hence, leads to network architecture with inferior accuracy. Head-wise search space achieves the right balance between flexibility and optimizability." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 47, + 671, + 198, + 683 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 671, + 198, + 683 + ], + "spans": [ + { + "bbox": [ + 47, + 671, + 198, + 683 + ], + "type": "text", + "content": "5.4. Ablation Study of MPCViT" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "type": "text", + "content": "Contribution of KD. One of our key techniques for training heterogeneous ViT is KD. We enumerate different" + } + ] + } + ], + "index": 14 + }, + { + "type": "table", + "bbox": [ + 337, + 277, + 517, + 316 + ], + "blocks": [ + { + "bbox": [ + 305, + 255, + 545, + 276 + ], + "lines": [ + { + "bbox": [ + 305, + 255, + 545, + 276 + ], + "spans": [ + { + "bbox": [ + 305, + 255, + 545, + 276 + ], + "type": "text", + "content": "Table 3. Top-1 accuracy (%) comparison with different structure granularities of attention search space with different " + }, + { + "bbox": [ + 305, + 255, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\mu" + }, + { + "bbox": [ + 305, + 255, + 545, + 276 + ], + "type": "text", + "content": " ." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 337, + 277, + 517, + 316 + ], + "lines": [ + { + "bbox": [ + 337, + 277, + 517, + 316 + ], + "spans": [ + { + "bbox": [ + 337, + 277, + 517, + 316 + ], + "type": "table", + "html": "
GranularityLayer-wiseRow-wiseHead-wise
μ = 0.593.0193.1693.21
μ = 0.793.3293.1393.38
", + "image_path": "a2573a07ed3aea120e2554a1615fabbad238d434442e06028a9d20cdadeda0d5.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "table_body" + } + ], + "index": 16 + }, + { + "type": "table", + "bbox": [ + 321, + 349, + 529, + 401 + ], + "blocks": [ + { + "bbox": [ + 305, + 327, + 545, + 348 + ], + "lines": [ + { + "bbox": [ + 305, + 327, + 545, + 348 + ], + "spans": [ + { + "bbox": [ + 305, + 327, + 545, + 348 + ], + "type": "text", + "content": "Table 4. Top-1 Accuracy " + }, + { + "bbox": [ + 305, + 327, + 545, + 348 + ], + "type": "inline_equation", + "content": "(\\%)" + }, + { + "bbox": [ + 305, + 327, + 545, + 348 + ], + "type": "text", + "content": " comparison of different combinations of training loss function with " + }, + { + "bbox": [ + 305, + 327, + 545, + 348 + ], + "type": "inline_equation", + "content": "\\mu = 0.7" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 321, + 349, + 529, + 401 + ], + "lines": [ + { + "bbox": [ + 321, + 349, + 529, + 401 + ], + "spans": [ + { + "bbox": [ + 321, + 349, + 529, + 401 + ], + "type": "table", + "html": "
CELogits-based KDFeature-based KDCIFAR-10Tiny-ImageNet
✓93.3859.02
✓✓94.1862.39
✓✓94.1262.26
✓✓94.1461.80
✓✓✓94.2763.03
", + "image_path": "9a08e4441199f55b3738a89daa53ab570f7de6794928e36b3fc1ae53bb8fddca.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "table_body" + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 423, + 545, + 507 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 423, + 545, + 507 + ], + "spans": [ + { + "bbox": [ + 304, + 423, + 545, + 507 + ], + "type": "text", + "content": "combinations of KD and the results are shown in Table 4. We find that: 1) both logits-based and feature-based KD significantly improve the performance of ViT compared to using cross-entropy loss only; and 2) combining the two KD losses further improves the accuracy, especially on a larger dataset. The above findings indicate the importance of KD and the indispensability of three parts of " + }, + { + "bbox": [ + 304, + 423, + 545, + 507 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{train}" + }, + { + "bbox": [ + 304, + 423, + 545, + 507 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "spans": [ + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "type": "text", + "content": "Consistency and scalability of NAS algorithm. We hope our NAS algorithm to be robust against hyperparameter choices and datasets. To analyze this consistency of our algorithm, we adjust the coefficient " + }, + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "type": "text", + "content": " to three different values, i.e., " + }, + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "type": "inline_equation", + "content": "10^{-3}, 10^{-4}, 10^{-5}" + }, + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "type": "text", + "content": ", and train a 7-layer ViT with 4 heads. We visualize the distribution of the architecture parameter " + }, + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "type": "text", + "content": " in Figure 9, and we find that " + }, + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "type": "text", + "content": " in each layer has a quite similar trend under different " + }, + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 509, + 546, + 675 + ], + "type": "text", + "content": "'s. Furthermore, when we change the number of heads to 8, or even train the same architecture on different datasets like CIFAR-100 and ImageNet, the distribution still shows a similar trend, empirically proving the consistency and scalability of our proposed NAS algorithm. Appendix F shows more distribution trends under other settings." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "content": "Comparison with per-layer search. We also compare MPCViT with per-layer search which replaces RSA ttn heads in each layer uniformly given a certain " + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mu" + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "content": " across three" + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5059" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 72, + 289, + 171 + ], + "blocks": [ + { + "bbox": [ + 49, + 72, + 289, + 171 + ], + "lines": [ + { + "bbox": [ + 49, + 72, + 289, + 171 + ], + "spans": [ + { + "bbox": [ + 49, + 72, + 289, + 171 + ], + "type": "image", + "image_path": "41d509e09a40f9937343b174f4d3340846d1bdcb18c6435f4f1a0030c24e1bfa.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 49, + 171, + 287, + 269 + ], + "blocks": [ + { + "bbox": [ + 49, + 171, + 287, + 269 + ], + "lines": [ + { + "bbox": [ + 49, + 171, + 287, + 269 + ], + "spans": [ + { + "bbox": [ + 49, + 171, + 287, + 269 + ], + "type": "image", + "image_path": "2ebc105be725a058dedd504b816301009ae3ab96525dc380b8d56cb549902ec7.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 271, + 287, + 305 + ], + "lines": [ + { + "bbox": [ + 46, + 271, + 287, + 305 + ], + "spans": [ + { + "bbox": [ + 46, + 271, + 287, + 305 + ], + "type": "text", + "content": "Figure 9. The distribution of architecture parameter " + }, + { + "bbox": [ + 46, + 271, + 287, + 305 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 271, + 287, + 305 + ], + "type": "text", + "content": " for each head under different " + }, + { + "bbox": [ + 46, + 271, + 287, + 305 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 271, + 287, + 305 + ], + "type": "text", + "content": " and different # heads on different datasets. We draw the average " + }, + { + "bbox": [ + 46, + 271, + 287, + 305 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 271, + 287, + 305 + ], + "type": "text", + "content": " in each layer to show the similar trend." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 323, + 287, + 371 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 323, + 287, + 371 + ], + "spans": [ + { + "bbox": [ + 46, + 323, + 287, + 371 + ], + "type": "text", + "content": "datasets. As shown in Figure 7, MPCViT achieves a better Pareto front for accuracy and efficiency compared to the per-layer NAS. The results demonstrate the importance to search and replace RSAtn heads across different layers." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 378, + 173, + 389 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 378, + 173, + 389 + ], + "spans": [ + { + "bbox": [ + 47, + 378, + 173, + 389 + ], + "type": "text", + "content": "5.5. MPCViT+ Evaluation" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 396, + 287, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 396, + 287, + 552 + ], + "spans": [ + { + "bbox": [ + 46, + 396, + 287, + 552 + ], + "type": "text", + "content": "As shown in Figure 7, when " + }, + { + "bbox": [ + 46, + 396, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mu" + }, + { + "bbox": [ + 46, + 396, + 287, + 552 + ], + "type": "text", + "content": " decreases to 0.1, the major latency bottleneck comes from GeLU in MLP. We evaluate MPCViT+ for GeLU reduction on CIFAR-10/100 datasets with KD, which correspond to the ViT models with significant GeLU latency. We take token-wise optimization as an example (exploration for other granularity, i.e., layer-wise is shown in Appendix E), and control the GeLU linearization rate using a threshold " + }, + { + "bbox": [ + 46, + 396, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 46, + 396, + 287, + 552 + ], + "type": "text", + "content": " such that " + }, + { + "bbox": [ + 46, + 396, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\beta \\leftarrow 0(\\beta \\leq \\sigma)" + }, + { + "bbox": [ + 46, + 396, + 287, + 552 + ], + "type": "text", + "content": " while " + }, + { + "bbox": [ + 46, + 396, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\beta \\leftarrow 1(\\beta >\\sigma)" + }, + { + "bbox": [ + 46, + 396, + 287, + 552 + ], + "type": "text", + "content": ". As shown in Figure 10, GeLU linearization leads to a little accuracy degradation, indicating that GeLU plays an important role in ViTs. MPCViT+ further reduces the latency on the basis of attention optimization, which proves the effectiveness of MPCViT+." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 552, + 287, + 624 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 552, + 287, + 624 + ], + "spans": [ + { + "bbox": [ + 46, + 552, + 287, + 624 + ], + "type": "text", + "content": "Ablation study of additional ReLU. To analyze the help of adding additional ReLU after the fused linear layer, we fix " + }, + { + "bbox": [ + 46, + 552, + 287, + 624 + ], + "type": "inline_equation", + "content": "\\sigma = 0.75" + }, + { + "bbox": [ + 46, + 552, + 287, + 624 + ], + "type": "text", + "content": " and perform the ablation study for MPCViT" + }, + { + "bbox": [ + 46, + 552, + 287, + 624 + ], + "type": "inline_equation", + "content": "^{+}" + }, + { + "bbox": [ + 46, + 552, + 287, + 624 + ], + "type": "text", + "content": " under different latency constraints on CIFAR-10 dataset in Table 5. The results show that additional ReLU improves the representation ability of MPCViT" + }, + { + "bbox": [ + 46, + 552, + 287, + 624 + ], + "type": "inline_equation", + "content": "^{+}" + }, + { + "bbox": [ + 46, + 552, + 287, + 624 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 61, + 653, + 276, + 700 + ], + "blocks": [ + { + "bbox": [ + 47, + 632, + 287, + 653 + ], + "lines": [ + { + "bbox": [ + 47, + 632, + 287, + 653 + ], + "spans": [ + { + "bbox": [ + 47, + 632, + 287, + 653 + ], + "type": "text", + "content": "Table 5. Ablation study of adding additional ReLU after the fused linear layer under different latency constraints." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 61, + 653, + 276, + 700 + ], + "lines": [ + { + "bbox": [ + 61, + 653, + 276, + 700 + ], + "spans": [ + { + "bbox": [ + 61, + 653, + 276, + 700 + ], + "type": "table", + "html": "
μ0.30.7
Accuracy (%)Latency (s)Accuracy (%)Latency (s)
MPCViT+93.9243.8894.2754.56
w/o ReLU93.7241.3793.8152.11
", + "image_path": "44c33377852467c5f9a7ebfa80997670a2f601f881c76a7ab21204de79b6aee2.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 309, + 72, + 425, + 167 + ], + "blocks": [ + { + "bbox": [ + 309, + 72, + 425, + 167 + ], + "lines": [ + { + "bbox": [ + 309, + 72, + 425, + 167 + ], + "spans": [ + { + "bbox": [ + 309, + 72, + 425, + 167 + ], + "type": "image", + "image_path": "962443157ace73d90e6a5aa7a29b14025b7483af36a183b369b32fa47cfdbc26.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 318, + 171, + 529, + 182 + ], + "lines": [ + { + "bbox": [ + 318, + 171, + 529, + 182 + ], + "spans": [ + { + "bbox": [ + 318, + 171, + 529, + 182 + ], + "type": "text", + "content": "Figure 10. Comparison between MPCViT and MPCViT+." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 426, + 72, + 544, + 167 + ], + "blocks": [ + { + "bbox": [ + 426, + 72, + 544, + 167 + ], + "lines": [ + { + "bbox": [ + 426, + 72, + 544, + 167 + ], + "spans": [ + { + "bbox": [ + 426, + 72, + 544, + 167 + ], + "type": "image", + "image_path": "335b881b5710163e9ea935136e4978b341b135ca3f1926a835d686f4b634e513.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 201, + 378, + 214 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 201, + 378, + 214 + ], + "spans": [ + { + "bbox": [ + 306, + 201, + 378, + 214 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 223, + 545, + 354 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 223, + 545, + 354 + ], + "spans": [ + { + "bbox": [ + 304, + 223, + 545, + 354 + ], + "type": "text", + "content": "In this paper, we present an MPC-friendly ViT family, dubbed MPCViT, to enable accurate yet efficient ViT inference in MPC. We propose a heterogeneous attention optimization space, and design an MPC-aware differentiable NAS algorithm to explore the search space. To further boost the inference efficiency, we propose " + }, + { + "bbox": [ + 304, + 223, + 545, + 354 + ], + "type": "inline_equation", + "content": "\\mathrm{MPCViT^{+}}" + }, + { + "bbox": [ + 304, + 223, + 545, + 354 + ], + "type": "text", + "content": " to jointly optimize attention and MLP. Extensive experiments demonstrate that MPCViT consistently outperforms prior-art ViT architectures with both lower latency and higher accuracy. Our method can be further applied to large language models (LLMs) including BERT and GPT." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 367, + 403, + 380 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 367, + 403, + 380 + ], + "spans": [ + { + "bbox": [ + 306, + 367, + 403, + 380 + ], + "type": "text", + "content": "Acknowledgement" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 388, + 545, + 411 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 388, + 545, + 411 + ], + "spans": [ + { + "bbox": [ + 306, + 388, + 545, + 411 + ], + "type": "text", + "content": "This work is supported in part by the NSFC (62125401) and the 111 Project (B18001)." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 424, + 365, + 436 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 424, + 365, + 436 + ], + "spans": [ + { + "bbox": [ + 306, + 424, + 365, + 436 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 310, + 444, + 547, + 714 + ], + "type": "list", + "angle": 0, + "index": 23, + "blocks": [ + { + "bbox": [ + 310, + 444, + 545, + 475 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 444, + 545, + 475 + ], + "spans": [ + { + "bbox": [ + 310, + 444, + 545, + 475 + ], + "type": "text", + "content": "[1] Saba Akram and Quarrat Ul Ann. Newton raphson method. International Journal of Scientific & Engineering Research, 6(7):1748-1752, 2015. 13" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 311, + 476, + 547, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 476, + 547, + 529 + ], + "spans": [ + { + "bbox": [ + 311, + 476, + 547, + 529 + ], + "type": "text", + "content": "[2] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In Proceedings of the IEEE/CVF international conference on computer vision, pages 6836-6846, 2021. 1" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 311, + 529, + 547, + 583 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 529, + 547, + 583 + ], + "spans": [ + { + "bbox": [ + 311, + 529, + 547, + 583 + ], + "type": "text", + "content": "[3] Gilad Asharov, Yehuda Lindell, Thomas Schneider, and Michael Zohner. More efficient oblivious transfer and extensions for faster secure computation. In ACM SIGSAC conference on Computer & Communications Security (CCS), pages 535-548, 2013. 14" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 311, + 584, + 547, + 627 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 584, + 547, + 627 + ], + "spans": [ + { + "bbox": [ + 311, + 584, + 547, + 627 + ], + "type": "text", + "content": "[4] Daniel Bolya, Cheng-Yang Fu, Xiaoliang Dai, Peizhao Zhang, and Judy Hoffman. Hydra attention: Efficient attention with many heads. In European Conference on Computer Vision, pages 35-49. Springer, 2022. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 311, + 627, + 545, + 658 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 627, + 545, + 658 + ], + "spans": [ + { + "bbox": [ + 311, + 627, + 545, + 658 + ], + "type": "text", + "content": "[5] Jason Ross Brown, Yiren Zhao, Ilia Shumailov, and Robert D Mullins. Dartformer: Finding the best type of attention. arXiv preprint arXiv:2210.00641, 2022. 2, 5" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 311, + 658, + 547, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 658, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 311, + 658, + 547, + 714 + ], + "type": "text", + "content": "[6] Tianyu Chen, Hangbo Bao, Shaohan Huang, Li Dong, Binxing Jiao, Daxin Jiang, Haoyi Zhou, Jianxin Li, and Furu Wei. THE-X: Privacy-preserving transformer inference with homomorphic encryption. In Findings of the Association for Computational Linguistics: ACL 2022, pages 3510-3520," + } + ] + } + ], + "index": 22 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5060" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 707 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "type": "text", + "content": "Dublin, Ireland, May 2022. Association for Computational Linguistics. 2, 3, 7" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 53, + 95, + 287, + 137 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 95, + 287, + 137 + ], + "spans": [ + { + "bbox": [ + 53, + 95, + 287, + 137 + ], + "type": "text", + "content": "[7] Minsu Cho, Zahra Ghodsi, Brandon Reagen, Siddharth Garg, and Chinmay Hegde. Sphynx: Relu-efficient network design for private inference. arXiv preprint arXiv:2106.11755, 2021. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 137, + 287, + 180 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 137, + 287, + 180 + ], + "spans": [ + { + "bbox": [ + 53, + 137, + 287, + 180 + ], + "type": "text", + "content": "[8] Minsu Cho, Ameya Joshi, Brandon Reagen, Siddharth Garg, and Chinmay Hegde. Selective network linearization for efficient private inference. In International Conference on Machine Learning, pages 3947-3961. PMLR, 2022. 3, 15" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 180, + 287, + 223 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 180, + 287, + 223 + ], + "spans": [ + { + "bbox": [ + 53, + 180, + 287, + 223 + ], + "type": "text", + "content": "[9] Ronald Cramer, Ivan Damgård, Daniel Escudero, Peter Scholl, and Chaoping Xing. SpdZ2k: Efficient mpc mod 2k for dishonest majority. In Annual International Cryptology Conference. Springer, pages 769-798, 2018. 4, 7, 13" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 223, + 287, + 287 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 223, + 287, + 287 + ], + "spans": [ + { + "bbox": [ + 48, + 223, + 287, + 287 + ], + "type": "text", + "content": "[10] Xiaoliang Dai, Peizhao Zhang, Bichen Wu, Hongxu Yin, Fei Sun, Yanghan Wang, Marat Dukhan, Yunqing Hu, Yiming Wu, Yangqing Jia, et al. Chamnet: Towards efficient network design through platform-aware model adaptation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11398-11407, 2019. 5" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 287, + 287, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 287, + 287, + 374 + ], + "spans": [ + { + "bbox": [ + 48, + 287, + 287, + 374 + ], + "type": "text", + "content": "[11] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In 9th International Conference on Learning Representations, ICLR 2021, Virtual Event, Austria, May 3-7, 2021. OpenReview.net, 2021. 1, 2, 4, 13" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 374, + 287, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 374, + 287, + 407 + ], + "spans": [ + { + "bbox": [ + 48, + 374, + 287, + 407 + ], + "type": "text", + "content": "[12] Hanan Gani, Muzammal Naseer, and Mohammad Yaqub. How to train vision transformer on small-scale datasets? arXiv preprint arXiv:2210.07240, 2022. 7" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 407, + 287, + 449 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 407, + 287, + 449 + ], + "spans": [ + { + "bbox": [ + 48, + 407, + 287, + 449 + ], + "type": "text", + "content": "[13] Zahra Ghodsi, Akshaj Kumar Veldanda, Brandon Reagen, and Siddharth Garg. Cryptonas: Private inference on a relu budget. Advances in Neural Information Processing Systems, 33:16961-16971, 2020. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 449, + 287, + 469 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 449, + 287, + 469 + ], + "spans": [ + { + "bbox": [ + 48, + 449, + 287, + 469 + ], + "type": "text", + "content": "[14] Oded Goldreich. Secure multi-party computation. 1998. 1, 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 469, + 287, + 524 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 469, + 287, + 524 + ], + "spans": [ + { + "bbox": [ + 48, + 469, + 287, + 524 + ], + "type": "text", + "content": "[15] Chengyue Gong, Dilin Wang, Meng Li, Xinlei Chen, Zhicheng Yan, Yuandong Tian, Vikas Chandra, et al. Nasvit: Neural architecture search for efficient vision transformers with gradient conflict aware supernet training. In International Conference on Learning Representations, 2021. 1" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 524, + 287, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 524, + 287, + 588 + ], + "spans": [ + { + "bbox": [ + 48, + 524, + 287, + 588 + ], + "type": "text", + "content": "[16] Jiaqi Gu, Hyoukjun Kwon, Dilin Wang, Wei Ye, Meng Li, Yu-Hsin Chen, Liangzhen Lai, Vikas Chandra, and David Z Pan. Multi-scale high-resolution vision transformer for semantic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12094-12103, 2022. 1" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 588, + 287, + 642 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 588, + 287, + 642 + ], + "spans": [ + { + "bbox": [ + 48, + 588, + 287, + 642 + ], + "type": "text", + "content": "[17] Minghao Guo, Zhao Zhong, Wei Wu, Dahua Lin, and Junjie Yan. Irlas: Inverse reinforcement learning for architecture search. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9021-9029, 2019. 5" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 642, + 287, + 685 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 642, + 287, + 685 + ], + "spans": [ + { + "bbox": [ + 48, + 642, + 287, + 685 + ], + "type": "text", + "content": "[18] Meng Hao, Hongwei Li, Hanxiao Chen, Pengzhi Xing, Guowen Xu, and Tianwei Zhang. Iron: Private inference on transformers. Advances in neural information processing systems, 2022. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 685, + 287, + 707 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 685, + 287, + 707 + ], + "spans": [ + { + "bbox": [ + 48, + 685, + 287, + 707 + ], + "type": "text", + "content": "[19] Ali Hassani, Steven Walton, Nikhil Shah, Abulikemu Abuduweili, Jiachen Li, and Humphrey Shi. Escaping the" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 707 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "text", + "content": "big data paradigm with compact transformers. arXiv preprint arXiv:2104.05704, 2021. 7" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 95, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 95, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 307, + 95, + 545, + 116 + ], + "type": "text", + "content": "[20] Dan Hendrycks and Kevin Gimpel. Gaussian error linear units (gelus). arXiv preprint arXiv:1606.08415, 2016. 13" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 116, + 545, + 147 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 116, + 545, + 147 + ], + "spans": [ + { + "bbox": [ + 307, + 116, + 545, + 147 + ], + "type": "text", + "content": "[21] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, et al. Distilling the knowledge in a neural network. arXiv preprint arXiv:1503.02531, 2(7), 2015. 6" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 147, + 545, + 201 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 147, + 545, + 201 + ], + "spans": [ + { + "bbox": [ + 307, + 147, + 545, + 201 + ], + "type": "text", + "content": "[22] Zhicong Huang, Wen jie Lu, Cheng Hong, and Jiansheng Ding. Cheetah: Lean and fast secure Two-Party deep neural network inference. In USENIX Security Symposium (USENIX Security), pages 809–826, Boston, MA, Aug. 2022. 4, 7, 13" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 201, + 545, + 222 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 201, + 545, + 222 + ], + "spans": [ + { + "bbox": [ + 307, + 201, + 545, + 222 + ], + "type": "text", + "content": "[23] Ethan Huynh. Vision transformers in 2022: An update on tiny imagenet. arXiv preprint arXiv:2205.10660, 2022. 7" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 222, + 545, + 264 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 222, + 545, + 264 + ], + "spans": [ + { + "bbox": [ + 307, + 222, + 545, + 264 + ], + "type": "text", + "content": "[24] Yesmina JAAFra, Jean Luc Laurent, Aline Deruyver, and Mohamed Saber Naceur. Reinforcement learning for neural architecture search: A review. Image and Vision Computing, 89:57-66, 2019. 5" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 264, + 545, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 264, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 307, + 264, + 545, + 308 + ], + "type": "text", + "content": "[25] Nandan Kumar Jha, Zahra Ghodsi, Siddharth Garg, and Brandon Reagen. Deepreduce: Relu reduction for fast private inference. In International Conference on Machine Learning, pages 4839-4849. PMLR, 2021. 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 308, + 545, + 340 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 308, + 545, + 340 + ], + "spans": [ + { + "bbox": [ + 307, + 308, + 545, + 340 + ], + "type": "text", + "content": "[26] Nandan Kumar Jha and Brandon Reagen. Deepreshape: Redesigning neural networks for efficient private inference. arXiv preprint arXiv:2304.10593, 2023. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 340, + 545, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 340, + 545, + 403 + ], + "spans": [ + { + "bbox": [ + 307, + 340, + 545, + 403 + ], + "type": "text", + "content": "[27] Weiwen Jiang, Lei Yang, Edwin Hsing-Mean Sha, Qingfeng Zhuge, Shouzhen Gu, Sakyasingha Dasgupta, Yiyu Shi, and Jingtong Hu. Hardware/software co-exploration of neural architectures. IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 39(12):4805-4815, 2020. 5" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 403, + 545, + 448 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 403, + 545, + 448 + ], + "spans": [ + { + "bbox": [ + 307, + 403, + 545, + 448 + ], + "type": "text", + "content": "[28] Jacob Devlin Ming-Wei Chang Kenton and Lee Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of naacL-HLT, volume 1, page 2, 2019. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 448, + 545, + 500 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 448, + 545, + 500 + ], + "spans": [ + { + "bbox": [ + 307, + 448, + 545, + 500 + ], + "type": "text", + "content": "[29] Nikita Kitaev, Lukasz Kaiser, and Anselm Levskaya. Reformer: The efficient transformer. In 8th International Conference on Learning Representations, ICLR 2020, Addis Ababa, Ethiopia, April 26-30, 2020. OpenReview.net, 2020. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 500, + 545, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 500, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 307, + 500, + 545, + 555 + ], + "type": "text", + "content": "[30] Brian Knott, Shobha Venkataraman, Awni Hannun, Shubho Sengupta, Mark Ibrahim, and Laurens van der Maaten. Crypten: Secure multi-party computation meets machine learning. Advances in Neural Information Processing Systems, 34:4961-4973, 2021. 13" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 555, + 545, + 619 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 555, + 545, + 619 + ], + "spans": [ + { + "bbox": [ + 307, + 555, + 545, + 619 + ], + "type": "text", + "content": "[31] Souvik Kundu, Shunlin Lu, Yuke Zhang, Jacqueline Tiffany Liu, and Peter A. Beerel. Learning to linearize deep neural networks for secure and efficient private inference. In The Eleventh International Conference on Learning Representations, ICLR 2023, Kigali, Rwanda, May 1-5, 2023. OpenReview.net, 2023. 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 619, + 545, + 651 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 619, + 545, + 651 + ], + "spans": [ + { + "bbox": [ + 307, + 619, + 545, + 651 + ], + "type": "text", + "content": "[32] Seunghoon Lee, Seunghyun Lee, and Byung Cheol Song. Improving vision transformers to learn small-size dataset from scratch. IEEE Access, 10:123212-123224, 2022. 7" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 651, + 545, + 707 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 651, + 545, + 707 + ], + "spans": [ + { + "bbox": [ + 307, + 651, + 545, + 707 + ], + "type": "text", + "content": "[33] Dacheng Li, Hongyi Wang, Rulin Shao, Han Guo, Eric P. Xing, and Hao Zhang. MPCFORMER: fast, performant and provate transformer inference with MPC. In The Eleventh International Conference on Learning Representations, ICLR 2023, Kigali, Rwanda, May 1-5, 2023. OpenReview.net," + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "5061" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 706 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 67, + 72, + 138, + 83 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 138, + 83 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 138, + 83 + ], + "type": "text", + "content": "2023. 2, 3, 4, 7, 14" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 83, + 287, + 115 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 83, + 287, + 115 + ], + "spans": [ + { + "bbox": [ + 48, + 83, + 287, + 115 + ], + "type": "text", + "content": "[34] Zhexin Li, Tong Yang, Peisong Wang, and Jian Cheng. Q-vit: Fully differentiable quantization for vision transformer. arXiv preprint arXiv:2201.07703, 2022. 5" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 116, + 287, + 158 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 116, + 287, + 158 + ], + "spans": [ + { + "bbox": [ + 48, + 116, + 287, + 158 + ], + "type": "text", + "content": "[35] Yahui Liu, Enver Sangineto, Wei Bi, Nicu Sebe, Bruno Lepri, and Marco Nadai. Efficient training of visual transformers with small datasets. Advances in Neural Information Processing Systems, 34:23818-23830, 2021. 7" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 159, + 287, + 201 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 159, + 287, + 201 + ], + "spans": [ + { + "bbox": [ + 48, + 159, + 287, + 201 + ], + "type": "text", + "content": "[36] Zexiang Liu, Dong Li, Kaiyue Lu, Zhen Qin, Weixuan Sun, Jiacheng Xu, and Yiran Zhong. Neural architecture search on efficient transformers and beyond. arXiv preprint arXiv:2207.13955, 2022. 5" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 201, + 287, + 243 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 201, + 287, + 243 + ], + "spans": [ + { + "bbox": [ + 48, + 201, + 287, + 243 + ], + "type": "text", + "content": "[37] Qian Lou, Yilin Shen, Hongxia Jin, and Lei Jiang. Safenet: A secure, accurate and fast neural network inference. In International Conference on Learning Representations, 2020. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 243, + 287, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 243, + 287, + 297 + ], + "spans": [ + { + "bbox": [ + 48, + 243, + 287, + 297 + ], + "type": "text", + "content": "[38] Jiachen Lu, Jinghan Yao, Junge Zhang, Xiatian Zhu, Hang Xu, Weiguo Gao, Chunjing Xu, Tao Xiang, and Li Zhang. Soft: Softmax-free transformer with linear complexity. Advances in Neural Information Processing Systems, 34:21297-21309, 2021. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 298, + 287, + 373 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 298, + 287, + 373 + ], + "spans": [ + { + "bbox": [ + 48, + 298, + 287, + 373 + ], + "type": "text", + "content": "[39] Junming Ma, Yancheng Zheng, Jun Feng, Derun Zhao, Haoqi Wu, Wenjing Fang, Jin Tan, Chaofan Yu, Benyu Zhang, and Lei Wang. SecretFlow-SPU: A performant and User-Friendly framework for Privacy-Preserving machine learning. In 2023 USENIX Annual Technical Conference (USENIX ATC 23), pages 17–33, Boston, MA, July 2023. USENIX Association. 7" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 373, + 287, + 417 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 373, + 287, + 417 + ], + "spans": [ + { + "bbox": [ + 48, + 373, + 287, + 417 + ], + "type": "text", + "content": "[40] Andre Martins and Ramon Astudillo. From softmax to sparsemax: A sparse model of attention and multi-label classification. In International conference on machine learning, pages 1614-1623. PMLR, 2016. 4, 14" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 417, + 287, + 449 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 417, + 287, + 449 + ], + "spans": [ + { + "bbox": [ + 48, + 417, + 287, + 449 + ], + "type": "text", + "content": "[41] Paul Michel, Omer Levy, and Graham Neubig. Are sixteen heads really better than one? Advances in neural information processing systems, 32, 2019. 5, 15" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 449, + 287, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 449, + 287, + 491 + ], + "spans": [ + { + "bbox": [ + 48, + 449, + 287, + 491 + ], + "type": "text", + "content": "[42] Pratyush Mishra, Ryan Lehmkuhl, Akshayaram Srinivasan, Wenting Zheng, and Raluca Ada Popa. Delphi: A cryptographic inference service for neural networks. In USENIX Security Symposium, pages 2505-2522, 2020. 1, 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 491, + 287, + 534 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 491, + 287, + 534 + ], + "spans": [ + { + "bbox": [ + 48, + 491, + 287, + 534 + ], + "type": "text", + "content": "[43] Payman Mohassel and Peter Rindal. Aby3: A mixed protocol framework for machine learning. In Proceedings of the 2018 ACM SIGSAC conference on computer and communications security, pages 35-52, 2018. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 534, + 287, + 576 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 534, + 287, + 576 + ], + "spans": [ + { + "bbox": [ + 48, + 534, + 287, + 576 + ], + "type": "text", + "content": "[44] Payman Mohassel and Yupeng Zhang. Securel: A system for scalable privacy-preserving machine learning. In IEEE symposium on security and privacy (S&P), pages 19-38. IEEE, 2017. 3, 4" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 577, + 287, + 608 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 577, + 287, + 608 + ], + "spans": [ + { + "bbox": [ + 48, + 577, + 287, + 608 + ], + "type": "text", + "content": "[45] Moni Naor and Benny Pinkas. Computationally secure oblivious transfer. Journal of Cryptology, 18(1):1-35, 2005. 14" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 609, + 287, + 651 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 609, + 287, + 651 + ], + "spans": [ + { + "bbox": [ + 48, + 609, + 287, + 651 + ], + "type": "text", + "content": "[46] Zizheng Pan, Bohan Zhuang, Haoyu He, Jing Liu, and Jianfei Cai. Less is more: Pay less attention in vision transformers. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 2035-2043, 2022. 5" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 651, + 287, + 706 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 651, + 287, + 706 + ], + "spans": [ + { + "bbox": [ + 48, + 651, + 287, + 706 + ], + "type": "text", + "content": "[47] Hongwu Peng, Shanglin Zhou, Yukui Luo, Shijin Duan, Nuo Xu, Ran Ran, Shaoyi Huang, Chenghong Wang, Tong Geng, Ang Li, et al. Polympcnet: Towards relu-free neural architecture search in two-party computation based private inference. arXiv preprint arXiv:2209.09424, 2022. 3" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 708 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 127 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 127 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 127 + ], + "type": "text", + "content": "[48] Hongwu Peng, Shanglin Zhou, Yukui Luo, Nuo Xu, Shijin Duan, Ran Ran, Jiahui Zhao, Shaoyi Huang, Xi Xie, Chenghong Wang, et al. Rrnet: Towards relu-reduced neural network for two-party computation based private inference. arXiv preprint arXiv:2302.02292, 2023. 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 127, + 545, + 191 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 127, + 545, + 191 + ], + "spans": [ + { + "bbox": [ + 307, + 127, + 545, + 191 + ], + "type": "text", + "content": "[49] Zhen Qin, Weixuan Sun, Hui Deng, Dongxu Li, Yunshen Wei, Baohong Lv, Junjie Yan, Lingpeng Kong, and Yiran Zhong. cosformer: Rethinking softmax in attention. In The Tenth International Conference on Learning Representations, ICLR 2022, Virtual Event, April 25-29, 2022. OpenReview.net, 2022. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 192, + 545, + 246 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 192, + 545, + 246 + ], + "spans": [ + { + "bbox": [ + 308, + 192, + 545, + 246 + ], + "type": "text", + "content": "[50] Deevashwer Rathee, Mayank Rathee, Rahul Kranti Kiran Goli, Divya Gupta, Rahul Sharma, Nishanth Chandran, and Aseem Rastogi. Sirnn: A math library for secure rn n inference. In 2021 IEEE Symposium on Security and Privacy (SP), pages 1003-1020. IEEE, 2021. 14" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 246, + 545, + 300 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 246, + 545, + 300 + ], + "spans": [ + { + "bbox": [ + 308, + 246, + 545, + 300 + ], + "type": "text", + "content": "[51] Deevashwer Rathee, Mayank Rathee, Nishant Kumar, Nishanth Chandran, Divya Gupta, Aseem Rastogi, and Rahul Sharma. Cryptflow2: Practical 2-party secure inference. In ACM SIGSAC Conference on Computer and Communications Security (CCS), pages 325-342, 2020. 1" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 300, + 545, + 320 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 300, + 545, + 320 + ], + "spans": [ + { + "bbox": [ + 308, + 300, + 545, + 320 + ], + "type": "text", + "content": "[52] Adi Shamir. How to share a secret. Communications of the ACM, 22(11):612-613, 1979. 13" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 321, + 545, + 352 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 321, + 545, + 352 + ], + "spans": [ + { + "bbox": [ + 308, + 321, + 545, + 352 + ], + "type": "text", + "content": "[53] Jeong-geun Song. Ufo-vit: High performance linear vision transformer without softmax. arXiv preprint arXiv:2109.14382, 2021. 2, 4, 14" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 353, + 545, + 418 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 353, + 545, + 418 + ], + "spans": [ + { + "bbox": [ + 308, + 353, + 545, + 418 + ], + "type": "text", + "content": "[54] Xiu Su, Shan You, Jiyang Xie, Mingkai Zheng, Fei Wang, Chen Qian, Changshui Zhang, Xiaogang Wang, and Chang Xu. Vitas: Vision transformer architecture search. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXI, pages 139-157. Springer, 2022. 5" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 418, + 545, + 471 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 418, + 545, + 471 + ], + "spans": [ + { + "bbox": [ + 308, + 418, + 545, + 471 + ], + "type": "text", + "content": "[55] Mingxing Tan, Bo Chen, Ruoming Pang, Vijay Vasudevan, Mark Sandler, Andrew Howard, and Quoc V Le. Mnasnet: Platform-aware neural architecture search for mobile. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2820-2828, 2019. 5" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 472, + 545, + 568 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 472, + 545, + 568 + ], + "spans": [ + { + "bbox": [ + 308, + 472, + 545, + 568 + ], + "type": "text", + "content": "[56] Elena Voita, David Talbot, Fedor Moiseev, Rico Sennrich, and Ivan Titov. Analyzing multi-head self-attention: Specialized heads do the heavy lifting, the rest can be pruned. In Anna Korhonen, David R. Traum, and Lluis Marquez, editors, Proceedings of the 57th Conference of the Association for Computational Linguistics, ACL 2019, Florence, Italy, July 28- August 2, 2019, Volume 1: Long Papers, pages 5797-5808. Association for Computational Linguistics, 2019. 5, 15" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 569, + 545, + 622 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 569, + 545, + 622 + ], + "spans": [ + { + "bbox": [ + 308, + 569, + 545, + 622 + ], + "type": "text", + "content": "[57] Kuan Wang, Zhijian Liu, Yujun Lin, Ji Lin, and Song Han. Haq: Hardware-aware automated quantization with mixed precision. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 8612-8620, 2019. 5" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 624, + 545, + 654 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 624, + 545, + 654 + ], + "spans": [ + { + "bbox": [ + 308, + 624, + 545, + 654 + ], + "type": "text", + "content": "[58] Sinong Wang, Belinda Z Li, Madian Khabsa, Han Fang, and Hao Ma. Linformer: Self-attention with linear complexity. arXiv preprint arXiv:2006.04768, 2020. 2, 4, 7, 14" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 655, + 545, + 696 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 655, + 545, + 696 + ], + "spans": [ + { + "bbox": [ + 308, + 655, + 545, + 696 + ], + "type": "text", + "content": "[59] Xiaolong Wang, Ross Girshick, Abhinav Gupta, and Kaiming He. Non-local neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 7794-7803, 2018. 3, 4" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 697, + 545, + 708 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 697, + 545, + 708 + ], + "spans": [ + { + "bbox": [ + 308, + 697, + 545, + 708 + ], + "type": "text", + "content": "[60] Yongqin Wang, G Edward Suh, Wenjie Xiong, Benjamin" + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5062" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 354 + ], + "type": "list", + "angle": 0, + "index": 5, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 127 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 127 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 127 + ], + "type": "text", + "content": "Lefaudeau, Brian Knott, Murali Annavaram, and Hsien-Hsin S Lee. Characterization of mpc-based private inference for transformer-based models. In 2022 IEEE International Symposium on Performance Analysis of Systems and Software (ISPASS), pages 187-197. IEEE, 2022. 1, 7, 13, 14" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 127, + 287, + 192 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 127, + 287, + 192 + ], + "spans": [ + { + "bbox": [ + 48, + 127, + 287, + 192 + ], + "type": "text", + "content": "[61] Bichen Wu, Xiaoliang Dai, Peizhao Zhang, Yanghan Wang, Fei Sun, Yiming Wu, Yuandong Tian, Peter Vajda, Yangqing Jia, and Kurt Keutzer. Fbnet: Hardware-aware efficient convnet design via differentiable neural architecture search. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10734-10742, 2019. 5" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 192, + 288, + 268 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 192, + 288, + 268 + ], + "spans": [ + { + "bbox": [ + 48, + 192, + 288, + 268 + ], + "type": "text", + "content": "[62] Mengzhou Xia, Zexuan Zhong, and Danqi Chen. Structured pruning learns compact and accurate models. In Smaranda Muresan, Preslav Nakov, and Aline Villavicencio, editors, Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), ACL 2022, Dublin, Ireland, May 22-27, 2022, pages 1513-1528. Association for Computational Linguistics, 2022. 15" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 268, + 288, + 300 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 268, + 288, + 300 + ], + "spans": [ + { + "bbox": [ + 48, + 268, + 288, + 300 + ], + "type": "text", + "content": "[63] Andrew C Yao. Protocols for secure computations. In 23rd annual symposium on foundations of computer science (sfcs 1982), pages 160-164. IEEE, 1982. 14" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 300, + 288, + 354 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 300, + 288, + 354 + ], + "spans": [ + { + "bbox": [ + 48, + 300, + 288, + 354 + ], + "type": "text", + "content": "[64] Pengchuan Zhang, Xiyang Dai, Jianwei Yang, Bin Xiao, Lu Yuan, Lei Zhang, and Jianfeng Gao. Multi-scale vision longformer: A new vision transformer for high-resolution image encoding. In Proceedings of the IEEE/CVF international conference on computer vision, pages 2998-3008, 2021. 1" + } + ] + } + ], + "index": 4 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "5063" + } + ] + } + ], + "index": 6 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 11 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/d01da3cc-92b1-43b1-b6d0-867a68823626_content_list.json b/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/d01da3cc-92b1-43b1-b6d0-867a68823626_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..2e344d6d633cc641a347b53b6eb44046b0eec9df --- /dev/null +++ b/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/d01da3cc-92b1-43b1-b6d0-867a68823626_content_list.json @@ -0,0 +1,1981 @@ +[ + { + "type": "text", + "text": "MPI-Flow: Learning Realistic Optical Flow with Multiplane Images", + "text_level": 1, + "bbox": [ + 140, + 130, + 828, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Yingping Liang", + "bbox": [ + 145, + 179, + 279, + 199 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Jiaming Liu2", + "bbox": [ + 359, + 180, + 465, + 198 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1Beijing Institute of Technology", + "bbox": [ + 272, + 199, + 527, + 217 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Debing Zhang", + "bbox": [ + 545, + 180, + 666, + 198 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{2}$ Xiaohongshu Inc.", + "bbox": [ + 547, + 199, + 697, + 215 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Ying Fu $^{1*}$", + "bbox": [ + 750, + 180, + 828, + 198 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 250, + 313, + 266 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The accuracy of learning-based optical flow estimation models heavily relies on the realism of the training datasets. Current approaches for generating such datasets either employ synthetic data or generate images with limited realism. However, the domain gap of these data with real-world scenes constrains the generalization of the trained model to real-world applications. To address this issue, we investigate generating realistic optical flow datasets from real-world images. Firstly, to generate highly realistic new images, we construct a layered depth representation, known as multiplane images (MPI), from single-view images. This allows us to generate novel view images that are highly realistic. To generate optical flow maps that correspond accurately to the new image, we calculate the optical flows of each plane using the camera matrix and plane depths. We then project these layered optical flows into the output optical flow map with volume rendering. Secondly, to ensure the realism of motion, we present an independent object motion module that can separate the camera and dynamic object motion in MPI. This module addresses the deficiency in MPI-based single-view methods, where optical flow is generated only by camera motion and does not account for any object movement. We additionally devise a depth-aware inpainting module to merge new images with dynamic objects and address unnatural motion occlusions. We show the superior performance of our method through extensive experiments on real-world datasets. Moreover, our approach achieves state-of-the-art performance in both unsupervised and supervised training of learning-based models. The code will be made publicly available at: https://github.com/Sharpiless/MPI-Flow.", + "bbox": [ + 75, + 284, + 473, + 752 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 785, + 209, + 800 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Optical flow refers to the precise calculation of per-pixel motion between consecutive video frames. Its applications span a wide range of fields, including object tracking [10, 51], robot navigation [23, 41], three-dimensional (3D)", + "bbox": [ + 76, + 811, + 468, + 873 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/8e844a68db9a3d09806e8131d5e8cb1d25c391c6f54206fefc57145afc1cab14.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 501, + 250, + 627, + 354 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/03169b595941f422c7b2dde1d3c9bef26c81ae30ee51b95a2ffe63985f4001fe.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 633, + 250, + 759, + 356 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/d17c980ac8900ca411665bf4d481dbfbd5db15c428133f7aaab0ad3d27fc8c2a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 764, + 250, + 890, + 354 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/8c0900c23bc1bc953c01c4f74b3041bddccce71d00bd1153b855a0c44ab3f696.jpg", + "image_caption": [ + "(a) Depthstill. [1]", + "(b) RealFlow [12]", + "(d) Source image and details of generated flows from our method", + "Figure 1: Visual comparison of images reveals that our method, when compared with those based on real-world images [1, 12], demonstrates superior image realism. Our method also achieves fine optical flows by employing volume rendering in MPI and separate motions of the camera and object with the independent object motion module." + ], + "image_footnote": [], + "bbox": [ + 503, + 375, + 764, + 492 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/7433d0b51b7f26fcdf4cead53a8b2642c8617783130d423ab7dd8ea0b212f879.jpg", + "image_caption": [ + "(c) Ours" + ], + "image_footnote": [], + "bbox": [ + 764, + 375, + 888, + 492 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "reconstruction [24, 14], and visual simultaneous localization and mapping (SLAM) [52, 8, 29]. In recent years, with the rapid development of neural networks, learning-based methods [44, 45] have demonstrated significant advances compared to traditional model-based algorithms [3, 49, 50]. Conventional practices primarily rely on synthetic data, as demonstrated by [9, 18, 4]. Synthetic data contains exact optical flow labels and animated images. However, the domain gap between synthetic and real data hinders its further improvements in real-world applications.", + "bbox": [ + 496, + 642, + 893, + 794 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Recent studies have aimed to extract optical flow from real-world data by employing hand-made special hardware [2, 11, 34]. However, the rigidly controlled and inefficient collection procedure limits their applicability. To address this issue, Depthstillation [1], and RealFlow [12] have been proposed, which project each pixel in the real-world image onto the novel view frame with the help of random motions", + "bbox": [ + 496, + 795, + 893, + 900 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding Author: fuying@bit.edu.cn", + "bbox": [ + 94, + 886, + 328, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "13857", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "of virtual cameras or estimated flows. Nonetheless, both methods are limited by the lack of image realism, leading to issues such as collisions, holes, and artifacts, as illustrated in Figure 1. These limitations constrain the real-world performance of learning-based optical flow models [44, 45].", + "bbox": [ + 75, + 90, + 468, + 166 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To achieve higher image realism, we turn our attention to the use of single-view Multiplane Images (MPI) [53, 47, 54, 6, 13]. This line of work demonstrates remarkable single-view image rendering capabilities and effectively reduces collisions, holes, and artifacts commonly found in previous methods [1, 12]. These advancements contribute to higher image realism, prompting a natural question: Can high-realistic MPI methods be adapted to generate high-quality optical flow datasets for training purposes?", + "bbox": [ + 75, + 167, + 468, + 316 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To this end, we propose MPI-Flow, aiming to generate realistic optical flow datasets from real-world images. Specifically, we first review the image synthesis pipeline of MPI and devise an optical flow generation pipeline along with image synthesis. In this step, we build an MPI by warping single-view image features onto each layered plane with the predicted color and density. The color and density then be mapped into a realistic new image via volume rendering. With the layered planes, we extract optical flows with virtual camera motions from the rendered image and the real image. Second, as the MPI can only be applied in static scenes, which yield limited motion realism, we propose an independent object motion module and a depth-aware inpainting module to tackle this issue. The independent object motion module decouples dynamic objects from static scenes and applies different virtual camera matrices to calculate the motion of both dynamic and static parts. The depth-aware inpainting module is introduced to remove the object occlusion in the synthesized new image.", + "bbox": [ + 75, + 316, + 470, + 603 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "With MPI-Flow, a large number of single-view images can be used to generate large-scale training datasets with realistic images and motions. This enables learning-based optical flow models better generalization to a wide range of real-world scenes. Extensive experiments on real datasets demonstrate the effectiveness of our approach. In summary, our main contributions are as follows:", + "bbox": [ + 75, + 604, + 468, + 709 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We are the first to present a novel MPI-based optical flow dataset generation framework, namely MPI-Flow, which can significantly improve the realism of the generated images and motion.", + "- We present a novel independent object motion module for modeling dynamic objects in MPI, which can model realistic optical flow from camera motion and object motion simultaneously.", + "- We design a depth-aware inpainting module for realistic image inpainting, which can remove unnatural motion occlusions in generated images." + ], + "bbox": [ + 94, + 717, + 467, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 89, + 640, + 104 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this section, we review the most relevant studies on optical flow networks, optical flow dataset generation, and novel view image synthesis methods.", + "bbox": [ + 498, + 114, + 890, + 159 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Supervised Optical Flow Network. Early methods train deep neural networks to match patches across images [49]. FlowNet [9] first trains convolutional neural networks on the synthetic datasets with optical flow. Moreover, the follow-up methods [16, 17, 18, 32, 31] with advanced modules and network architectures make a significant improvement in supervised optical flow learning, with RAFT [45] representing state-of-the-art. However, generalization remains a cause for concern due to the domain gap between synthetic datasets and real-world applications. To address this problem, our work focuses on generating realistic optical flow datasets from real-world images.", + "bbox": [ + 498, + 160, + 890, + 340 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Dataset Generation for Optical Flow. The use of fluorescent texture to record motions in real-world scenes is first described in [2] to obtain flow maps. KITTI [11, 34] provides sophisticated training data through complex lidar and camera setups. However, the aforementioned real-world datasets have limited quantities and constrained scenes, making it difficult for models trained using deep supervised learning to generalize to more expansive scenes. Synthesized training pairs, such as those in Flyingchairs [9] and Flyingthings [18], have shown promise for supervised learning. However, moving animated image patches cannot accurately match real-world scenes, leading to domain gaps. AutoFlow [43] introduces a learning-based approach for generating training data by hyper-parameters searching. However, AutoFlow relies on optical flow labels for domain adaptation, which is not practical in most scenarios where ground truth labels are unavailable.", + "bbox": [ + 498, + 340, + 890, + 597 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Two recent works have proposed methods for generating training datasets based on real-world images or videos. The first, called Depthstillation [1], synthesizes paired images by estimating depth and optical flows from a single still image. Optical flows are calculated based on the virtual camera pose and depth. The second method, called RealFlow [12], synthesizes intermediate frames between two frames using estimated optical flows with RAFT. However, both methods use naive image synthesis techniques that fail to meet the demand for realism criteria due to hole-filling and artifacts. In contrast, our method improves on this approach by using a well-designed and modified multiplane image (MPI) technique to obtain realistic images.", + "bbox": [ + 498, + 599, + 890, + 792 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Novel View Synthesis. View synthesis methods aim to generate new images from arbitrary viewpoints by utilizing a given scene. Several classical approaches [48, 30, 53, 35] have been proposed that utilize multiple views of a scene to render novel views with geometric consistency. However, synthesizing novel views from a single image remains challenging due to the limited scene information available.", + "bbox": [ + 498, + 795, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "13858", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/de6823920601c4a5726be68fa470e124ef72f03b4ef82d2c20216b5838b136b9.jpg", + "image_caption": [ + "Figure 2: Illustration of our proposed MPI-Flow framework with single-view image $\\mathbf{I}_s$ as input. We estimate depths to construct MPI where RGB and density of each plane are predicted by neural networks and the flow of each plane is calculated with camera matrixes. Both the novel views and flow maps are rendered by volume rendering and separated by the independent object motion module with novel view object masks. The new image is merged by depth-aware inpainting." + ], + "image_footnote": [], + "bbox": [ + 101, + 90, + 867, + 390 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Pixelsynth [39] and Geometry-Free View Synthesis [40] address this challenge by optimizing the synthesizing model using multi-view supervision. However, their generalization to in-the-wild scenes is hindered by the lack of large-scale multi-view datasets. Single-view MPI [47] and MINE [26] decompose the scene into multiple layers and utilize an inpainting network to extend each occluded layer. Additionally, AdaMPI [13] addresses complex 3D scene structures through a novel plane adjustment network. These MPI-based methods have demonstrated success in synthesizing realistic images, and thus, we adopt multiplane images as our basic synthesis tool. However, to the best of our knowledge, there are currently no publicly available methods for generating optical flow datasets from MPI. To extract optical flows from MPI, we propose a novel pipeline that differs from previous MPI-based image synthesis methods by utilizing layered depths and virtual camera poses. Additionally, to enhance the realism of the generated optical flow dataset, we introduce an independent object motion module for static and dynamic decoupling, as well as a depth-aware inpainting module to remove unnatural occupations.", + "bbox": [ + 75, + 500, + 472, + 819 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. The Proposed MPI-Flow", + "text_level": 1, + "bbox": [ + 76, + 829, + 308, + 847 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this section, we first briefly review the basics of our motivation and formulation for novel view image generation. Then we introduce the optical flow generation", + "bbox": [ + 75, + 854, + 470, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "pipeline. Next, we present the details of two crucial components of our approach, including independent object motions and depth-aware inpainting.", + "bbox": [ + 496, + 500, + 892, + 547 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Motivation and Formulation", + "text_level": 1, + "bbox": [ + 498, + 558, + 756, + 571 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Our goal is to generate a realistic novel view image $\\mathbf{I}_t\\in \\mathbb{R}^{H\\times W\\times 3}$ and the corresponding optical flow maps $\\mathbf{F}_{s\\rightarrow t}\\in \\mathbb{R}^{H\\times W\\times 2}$ from single-view image $\\mathbf{I}_s\\in \\mathbb{R}^{H\\times W\\times 3}$ . $H$ and $W$ are the height and width of the image, respectively. The two-dimensional array on the optical flow $\\mathbf{F}_{s\\rightarrow t}$ represents the change of the corresponding pixel from image $\\mathbf{I}_s$ to image $\\mathbf{I}_t$ . The input image, generated image, and optical flow together form a training pair.", + "bbox": [ + 496, + 582, + 890, + 703 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To generate training pair, previous works [1, 12] wrap pixels from image $\\mathbf{I}_s$ to image $\\mathbf{I}_t$ with estimated flows. This inevitably leads to holes and artifacts in the image $\\mathbf{I}_t$ , which damages the image realism. Recent work [47, 26, 13] on Multiplane Images (MPI) reveals that the layered depth representation of the single-view image can significantly improve the realism of the generated novel view image.", + "bbox": [ + 496, + 704, + 890, + 809 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We aim to tackle the image realism challenges in our methods and meanwhile enhance the optical flow realism and motion realism. Accordingly, we present an MPI-based optical flow dataset generation method, namely MPI-Flow. Figure 2 shows the MPI-Flow framework for training pair generation. To construct MPI, given the input image $\\mathbf{I}_s$ ,", + "bbox": [ + 496, + 810, + 892, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "13859", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "an off-the-shelf monocular depth estimation network [38] is used to estimate its depth map. Then we use a neural network to construct $N$ fronto-parallel RGB $\\sigma$ planes with color, density, and depth predicted by neural networks in the rays under novel viewpoints.", + "bbox": [ + 75, + 90, + 468, + 166 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To decouple dynamic objects, an instance segmentation network [7] gives the object mask. Then we use bilinear interpolation to obtain the object masks under two viewpoints respectively. Using object masks and constructed MPI, we use volume rendering to render the separate novel view images, optical flow maps, and depths of dynamic objects and the static scene, respectively. The optical flow $\\mathbf{F}_{s\\rightarrow t}$ can be obtained simply by adding the optical flows of the objects and the scene. However, due to different viewpoints, merging new images results in vacant areas and false occlusion. To this end, we design a depth-aware inpainting module, using rendered depths and object masks to fill the holes and repair false occlusion in the synthesized new image $\\mathbf{I}_t$", + "bbox": [ + 75, + 167, + 470, + 363 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Optical Flow Data Generation", + "text_level": 1, + "bbox": [ + 76, + 371, + 346, + 387 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Novel View Image from MPI. To render realistic image $\\mathbf{I}_t$ under a target viewpoint $\\pmb{\\mu}_t$ , we use pixel warping from the source-view MPI in a differentiable manner. Specifically, we use a neural network $\\mathcal{F}$ as in [13] to construct $N$ frontoparallel RGB $\\sigma$ planes under source viewpoint $\\pmb{\\mu}_s$ with color channels $\\mathbf{c}_n$ , density channel $\\sigma_n$ , and depth $\\mathbf{d}_n$ from the input image $\\mathbf{I}_s$ and its depth map $\\mathbf{D}_s$ as:", + "bbox": [ + 75, + 393, + 468, + 500 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\left\\{\\left(\\mathbf {c} _ {n}, \\boldsymbol {\\sigma} _ {n}, \\mathbf {d} _ {n}\\right) \\right\\} _ {n = 1} ^ {N} = \\mathcal {F} \\left(\\mathbf {I} _ {s}, \\mathbf {D} _ {s}\\right), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 163, + 508, + 468, + 527 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $N$ is a predefined parameter that represents the number of planes in MPI. Each pixel $(x_{t},y_{t})$ on the novel view image plane can be mapped to pixel $(x_{s},y_{s})$ on $n$ -th source MPI plane via homography function [15]:", + "bbox": [ + 75, + 536, + 468, + 597 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\left[ x _ {s}, y _ {s}, 1 \\right] ^ {T} \\sim \\mathbf {K} \\left(\\mathbf {R} - \\frac {\\mathbf {t n} ^ {T}}{\\mathbf {d} _ {n}}\\right) \\mathbf {K} ^ {- 1} \\left[ x _ {t}, y _ {t}, 1 \\right] ^ {T}, \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 114, + 604, + 468, + 638 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbf{R}$ and $\\mathbf{t}$ are the rotation and translation from the source viewpoints $\\pmb{\\mu}_{s}$ to the target viewpoints $\\pmb{\\mu}_{t}$ , $\\mathbf{K}$ is the camera intrinsic, and $\\mathbf{n} = [0,0,1]$ is the normal vector. Thus, the color $\\mathbf{c}_n^\\prime$ and density $\\sigma_{n}^{\\prime}$ of each new plane for the novel view $\\mathbf{I}_t$ can be obtained via bilinear sampling. We use discrete intersection points between new planes and arbitrary rays passing through the scene and estimate integrals:", + "bbox": [ + 75, + 647, + 468, + 753 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {I} _ {t} = \\sum_ {n = 1} ^ {N} \\left(\\mathbf {c} _ {n} ^ {\\prime} \\boldsymbol {\\alpha} _ {n} ^ {\\prime} \\prod_ {m = 1} ^ {n - 1} \\left(1 - \\boldsymbol {\\alpha} _ {m} ^ {\\prime}\\right)\\right), \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 153, + 763, + 468, + 805 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\alpha_{n}^{\\prime} = \\exp \\left(-\\delta_{n}\\sigma_{n}^{\\prime}\\right)$ and $\\delta_{n}$ is the distance map between plane $n$ and $n + 1$ and we set the initial depth of MPI planes uniformly spaced in disparity as in [13].", + "bbox": [ + 75, + 809, + 468, + 854 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Optical Flow from MPI. Although MPI-based methods synthesize realistic images, reliable optical flow maps are", + "bbox": [ + 75, + 869, + 468, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "also needed to train learning-based optical flow estimation models. Therefore, we propose adding an additional optical channel in each plane. To this end, we compute the optical flow on the $n$ -th plane at pixel $[x_s, y_s]$ of source image $\\mathbf{I}_s$ by $\\mathbf{f}_n = [x_t - x_s, y_t - y_s]$ with a backward-warp process in terms of the inverse equivalent form of Equation (2):", + "bbox": [ + 496, + 90, + 890, + 181 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\left[ x _ {t}, y _ {t}, 1 \\right] ^ {T} \\sim \\mathbf {K} \\left(\\mathbf {R} ^ {\\dagger} - \\frac {\\mathbf {t} ^ {\\dagger} \\mathbf {n} ^ {T}}{\\mathbf {d} _ {n}}\\right) \\mathbf {K} ^ {- 1} \\left[ x _ {s}, y _ {s}, 1 \\right] ^ {T}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 521, + 193, + 890, + 229 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $x_{s}$ and $y_{s}$ are uniformly sampled from a $H\\times W$ grid. $\\mathbf{R}^{\\dagger}$ and $\\mathbf{t}^{\\dagger}$ are the inverses of $\\mathbf{R}$ and $\\mathbf{t}$ , respectively.", + "bbox": [ + 498, + 239, + 888, + 268 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To make sure that the optical flow maps match the novel view image $\\mathbf{I}_t$ perfectly, we propose to render $\\mathbf{F}_{s\\rightarrow t}$ as in Equation (3) in terms of volume rendering:", + "bbox": [ + 498, + 270, + 890, + 316 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {F} _ {s \\rightarrow t} = \\sum_ {n = 1} ^ {N} \\left(\\mathbf {f} _ {n} \\boldsymbol {\\alpha} _ {n} \\prod_ {m = 1} ^ {n - 1} (1 - \\boldsymbol {\\alpha} _ {m})\\right), \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 565, + 328, + 890, + 369 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbf{f}_n\\in \\mathbb{R}^{H\\times W\\times 2}$ is the optical flow maps on the $n$ -th plane of image $\\mathbf{I}_s$ . The pipeline implemented thus far models the optical flows resulting from camera motion without considering the potential presence of independently dynamic objects. However, real-world scenes are highly likely to contain such objects. Not incorporating their motions can lead to domain gaps by unrealistic optical flows.", + "bbox": [ + 496, + 382, + 890, + 489 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Independent Object Motions. To model more realistic motions, we propose applying separate virtual motions to objects and static backgrounds extracted from the scene. Therefore, we utilize an instance segmentation network $\\Omega$ [7] for extracting the main object in the source image $\\mathbf{I}_s$ as:", + "bbox": [ + 496, + 506, + 890, + 582 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {M} _ {s} = \\Omega (\\mathbf {I} _ {s}) \\in \\mathbb {R} ^ {H \\times W}, \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 614, + 595, + 890, + 614 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbf{M}_s$ is a binary mask to indicate the region of the object. To model the motions of the object $\\mathbf{M}_s$ in the scene, we construct separate viewpoints, including camera motion $\\pmb{\\mu}_t^{sce}$ and object motion $\\pmb{\\mu}_t^{obj}$ . We then obtain the rendered scene novel view $\\mathbf{I}_t^{sce}$ and object novel view $\\mathbf{I}_t^{obj}$ as in Equation (3). The separate optical flows, $\\mathbf{F}_{s\\rightarrow t}^{sce}$ and $\\mathbf{F}_{s\\rightarrow t}^{obj}$ can also be obtained as in Equation (5). The optical flows in $\\mathbf{F}_{s\\rightarrow t}$ are mixed by the values in $\\mathbf{F}_{s\\rightarrow t}^{sce}$ and $\\mathbf{F}_{s\\rightarrow t}^{obj}$ in terms of mask $\\mathbf{M}_s$ to get the final optical flow maps containing camera motion and dynamic objects for training.", + "bbox": [ + 496, + 623, + 890, + 777 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We can then use the bilinear interpolation to get the new object masks $\\mathbf{M}_t$ and $\\mathbf{M}_t^{obj}$ under the new viewpoints $\\pmb{\\mu}_t$ and $\\pmb{\\mu}_t^{obj}$ via bilinear sampling from $\\mathbf{M}_s$ . Pixels in the new merged image are also selected according to the content masks $1 - \\mathbf{M}_t$ and $\\mathbf{M}_t^{obj}$ from $\\mathbf{I}_t^{sce}$ and $\\mathbf{I}_t^{obj}$ . Then, a simple inpainting strategy [46] is used to fill the empty area in the new image with an inpainting mask calculated by $\\mathbf{M}_{fill} = \\mathbf{M}_t\\odot (1 - \\mathbf{M}_t^{obj})$ .", + "bbox": [ + 496, + 777, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "13860", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Depth-Aware Inpainting Although merged images give a realistic visual effect, depth changes caused by camera motion and object motion can also cause unnatural occlusions. To solve this problem, we use volume rendering to obtain the depth $\\mathbf{D}_t^{sce}$ of the scene novel view:", + "bbox": [ + 76, + 90, + 472, + 167 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {D} _ {t} = \\sum_ {n = 1} ^ {N} \\left(\\mathbf {d} _ {n} ^ {\\prime} \\boldsymbol {\\alpha} _ {n} ^ {\\prime} \\prod_ {m = 1} ^ {n - 1} \\left(1 - \\boldsymbol {\\alpha} _ {m} ^ {\\prime}\\right)\\right), \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 148, + 176, + 468, + 219 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "and the depth of the object novel view $\\mathbf{D}_t^{obj}$ can be obtained in the same way. We then utilize both depths to compute the occupation mask between the novel views:", + "bbox": [ + 76, + 228, + 468, + 275 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {M} _ {o c c} = \\left(1 - \\mathbf {M} _ {t}\\right) \\odot \\mathbf {M} _ {t} ^ {o b j} \\odot \\left(\\mathbf {D} _ {t} < \\mathbf {D} _ {t} ^ {o b j}\\right), \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 129, + 282, + 468, + 301 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "which indicates the background areas in front of the object. Therefore, we are able to restore the coincidence area between the object and the background in the new image $\\mathbf{I}_t$ .", + "bbox": [ + 76, + 311, + 468, + 356 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Figure 3 provides a detailed illustration of the incremental effects of MPI-Flow with and without independent object motion and depth-aware inpainting. Novel view images and optical flows from single-view images can be generated with MPI-Flow and only camera motion, as shown in Figures 3(a) and 3(b). However, camera motion alone does not match the complex optical flows in real-world scenes. To address this issue, we introduce an independent object motion module, as shown in Figure 3(c), to ensure motion realism. To further enhance motion realism and address occlusion caused by object motion, we apply the depth-aware inpainting module, as shown in Figure 3(d).", + "bbox": [ + 75, + 357, + 468, + 537 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 550, + 209, + 566 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Datasets", + "text_level": 1, + "bbox": [ + 76, + 575, + 179, + 589 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "FlyingChairs [9] and FlyingThings3D [18] are both popular synthetic datasets that train optical flow models. As a standard practice, we use \"Ch\" and \"Th\" respectively to represent the two datasets, and \"Ch→Th\" means training first on \"Ch\" and fine-tuning on \"Th\". By default, we use the RAFT pre-trained on \"Ch→Th\" to be fine-tuned on the generated datasets and evaluated on labeled datasets.", + "bbox": [ + 75, + 598, + 468, + 703 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "COCO [27] is a collection of single still images and ground truth with labels for object detection or panoptic segmentation tasks. We sample 20k single-view still images from the train2017 split following Depthstillation [1] to generate virtual images and optical flow maps.", + "bbox": [ + 75, + 704, + 468, + 779 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "DAVIS [37] provides high-resolution videos and it is widely used for video object segmentation. We use all the 10581 images of the unsupervised 2019 challenge to generate datasets by MPI-Flow and other state-of-the-art optical flow dataset generation methods.", + "bbox": [ + 75, + 779, + 468, + 853 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "KITTI2012 [11] and KITTI2015 [34] are well-known benchmarks for optical flow estimation. There are multi-view extensions (4,000 for training and 3,989 for testing)", + "bbox": [ + 76, + 854, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/18aa294b4c43e2cfbbfb26d4f0b4339699614dabe1ce6839da29630733a0f5b5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 511, + 88, + 882, + 176 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/483db86c9c2fd68689ceb6a2e941c4a4d1f64516dc3c1df0c175456ee79e1724.jpg", + "image_caption": [ + "(a) Source Image" + ], + "image_footnote": [], + "bbox": [ + 511, + 196, + 880, + 241 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/4eefc23d3c4e9dc0b40e238ae4ab1584fdf26a5c403f7fefd2a52d53aeeed15c.jpg", + "image_caption": [ + "(b) + Camera Motion" + ], + "image_footnote": [], + "bbox": [ + 511, + 260, + 880, + 305 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/1cb0d434562663e28645fa986f02ffedb6a994c4bd19a31bcee779da3164b59c.jpg", + "image_caption": [ + "(c) + Independent Object Motion", + "(d) + Depth-Aware Inpainting", + "Figure 3: Visualization of incrementally adding different modules to improve the realism of the generated data." + ], + "image_footnote": [], + "bbox": [ + 511, + 325, + 880, + 369 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "datasets with no ground truth. We use the multi-view extension images (training and testing) of KITTI 2015 to generate datasets, separately. By default, we evaluate the trained models on KITTI 12 training set and KITTI 15 training set in the tables following [1] and [12], abbreviated as \"KITTI 15\" and \"KITTI 12\" in the following tables.", + "bbox": [ + 498, + 459, + 890, + 549 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Sintel [5] is derived from the open-source 3D animated short film Sintel. The dataset has 23 different scenes. The stereo images are RGB, while the disparity is grayscale. Although not a real-world dataset, we use it to verify the model's generalization across domains.", + "bbox": [ + 498, + 550, + 890, + 625 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Implementation Details", + "text_level": 1, + "bbox": [ + 500, + 635, + 715, + 650 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Firstly, we provide a description of the learning-based optical flow estimation models that were utilized in our experiments. Subsequently, we outline the experimental parameters and setup along with the evaluation formulation.", + "bbox": [ + 498, + 659, + 890, + 719 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Optical Flow networks. To evaluate how effective our generated data are at training optical flow models, we select RAFT [45], which represents state-of-the-art architecture for supervised optical flow and has excellent generalization capability. By default, we train RAFT on generated data for 200K steps with a learning rate of $1 \\times 10^{-4}$ and weight decay of $1 \\times 10^{-5}$ , batch size of 6, and $288 \\times 960$ image crops. This configuration is the default setting of RAFT fitting on KITTI with two GPUs but four times the number of training steps, following [12]. For the rest of the setup, we use the official implementation of RAFT without any modifications. All evaluations are performed on a single NVIDIA", + "bbox": [ + 496, + 719, + 892, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "13861", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/4d5f62940ac52ed2e7e8245dd1529ec551f9ba6b66a4a0e8d174dcc37d4cd6f6.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Image SourceMethodSintel.CSintel.FKITTI 12KITTI 15
EPE ↓>3 ↓EPE ↓>3 ↓EPE ↓F1 ↓EPE ↓F1 ↓
COCODepthstillation [1]1.875.313.219.251.746.813.4513.08
RealFlow [12]N/AN/AN/AN/AN/AN/AN/AN/A
MPI-Flow (ours)1.874.593.168.291.364.913.4410.66
DAVISDepthstillation [1]2.707.523.8112.061.816.893.7913.22
RealFlow [12]1.734.813.478.711.596.083.5512.52
MPI-Flow (ours)1.794.773.068.561.415.363.3210.47
KITTI 15 TestDepthstillation [1]4.029.084.9613.231.775.973.9913.34
RealFlow [12]3.737.365.5311.311.275.162.438.86
MPI-Flow (ours)2.255.253.658.891.244.512.167.30
KITTI 15 TrainDepthstillation [1]2.847.184.3111.241.675.71{2.99}{9.94}
RealFlow [12]4.067.684.7811.441.255.02{2.17}{8.64}
MPI-Flow (ours)2.415.393.829.111.264.66{1.88}{7.16}
", + "bbox": [ + 140, + 88, + 831, + 287 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "GeForce RTX 3090 GPU1.", + "text_level": 1, + "bbox": [ + 76, + 400, + 261, + 415 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Virtual Camera Motion. To generate the novel view images from COCO and DAVIS, we adopt the same settings in [1] to build the virtual camera. For KITTI, we empirically build the camera motion with three scalars where $t_x, t_y$ are in $[-0.2, 0.2]$ and $t_z$ are in $[0.1, 0.35]$ . We build the camera rotation with three Euler angles $a_x, a_y, a_z$ in $[- \\frac{\\pi}{90}, \\frac{\\pi}{90}]$ . We use single camera motion for each image from COCO but multiple camera motions ( $\\times 4$ by default) from DAVIS and KITTI as in [12], due to the small number of images and the homogeneity of the scene in video data. We show how the number of camera motions impacts the optical flow network performance in the discussion.", + "bbox": [ + 75, + 416, + 470, + 595 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Evaluation Metrics. We report evaluation results on the average End-Point Error (EPE) and two error rates, respectively the percentage of pixels with an absolute error greater than $3 (> 3)$ or both absolute and relative errors greater than 3 and $5\\%$ respectively (Fl) on all pixels.", + "bbox": [ + 75, + 597, + 468, + 674 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Comparison with State-of-the-art Methods", + "text_level": 1, + "bbox": [ + 76, + 681, + 441, + 698 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this section, we evaluate the effectiveness of the MPI-Flow generation pipeline on public benchmarks. We will highlight the best results in **bold** and **underline** the second-best if necessary among methods trained in fair conditions.", + "bbox": [ + 75, + 705, + 468, + 766 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Comparison with Dataset Generation Methods. As a method for generating datasets from real-world images, we compare MPI-Flow with Depthstillation [1] and RealFlow [12], which are representative works in real-world dataset generation. In order to evaluate the effectiveness", + "bbox": [ + 75, + 766, + 468, + 842 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/84edfcf9c2076c005b02d44ffb962ccb6d873b37688659e73b1063e9bde53afd.jpg", + "table_caption": [ + "Table 1: The cross-dataset validation results and comparisons with other dataset generation methods from real images or videos are presented in this study. The \"Image Source\" column indicates the dataset used for optical flow training data generation. The evaluation results of RAFT trained on different datasets using different methods are reported. In cases where RealFlow fails to work on single-view images from COCO, the study indicates \"N/A\". The curly braces \"\\{\\}\" represent the use of the unlabeled evaluation set, which is the KITTI 15 training set in this table." + ], + "table_footnote": [], + "table_body": "
DatasetKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
Ch→Th [18]2.088.865.0017.44
dDAVIS [1]1.816.893.7913.22
MF-DAVIS1.616.413.7712.40
dCOCO [1]1.806.663.8012.44
MF-COCO1.596.223.6811.95
", + "bbox": [ + 540, + 398, + 854, + 500 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2: Results on RAFT trained from scratch under the same setting. \"dX\" are from Depthstillation [1] while \"MF-X\" are from our proposed MPI-Flow", + "bbox": [ + 498, + 508, + 890, + 556 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "of MPI-Flow, we follow the procedures of Depthstillation and RealFlow to construct training sets from four different datasets, including COCO, DAVIS, KITTI 15 multi-view train set, and KITTI 15 multi-view test set. To ensure fair comparisons, we conduct experiments with a similar number of training sets as our competitors. Specifically, for DAVIS and KITTI, we generate four motions for each image to match RealFlow, which trains RAFT for four EM iterations with four times the amount of data. For COCO, we follow the exact same setup as Depthstillation. Since Depthstillation does not provide details for KITTI 15 train, we use its default settings to obtain the results. Trained models are evaluated on the training sets of Sintel, KITTI 12, and KITTI 15. We report the evaluation results of models with the best performance in the paper for Depthstillation and RealFlow. Furthermore, we conduct cross-dataset experiments where RAFT is trained with one generated dataset and evaluated with another.", + "bbox": [ + 496, + 582, + 890, + 853 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "As shown in Table 1, even with the same amount of data, our approach gains significant improvements and generalization over multiple datasets. When trained and tested with", + "bbox": [ + 498, + 854, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_footnote", + "text": "$^{1}$ RAFT with the same parameters loaded on different GPUs yield slightly different evaluation results. Therefore, to ensure fair comparison, we download the official model weights with the best performance provided by the compared methods and evaluate them on the same GPU.", + "bbox": [ + 76, + 849, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "13862", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/6c9872874dbce6f88dc9e94435216586fb035fe14830981d04e3325f26840b4f.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 80, + 87, + 277, + 136 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/0d0e458a409fe6f74c3a7be43be012010775bfa27f6a9e5f0c16f4c9bed619f3.jpg", + "image_caption": [ + "(a) Source Image" + ], + "image_footnote": [], + "bbox": [ + 80, + 141, + 276, + 189 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/4a4f571291d256910cb7fdc5bcc3ac9761bf72e291cefb9b363bdd491dd55749.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 287, + 87, + 485, + 136 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/2263f6bc8e0fafe00c29c4a7545b33396f4f470f86c4198c3fc7583987ad8219.jpg", + "image_caption": [ + "(b) Depthstillation" + ], + "image_footnote": [], + "bbox": [ + 287, + 141, + 483, + 189 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/90a4d2644a51927d4c2d271836f4bca126553384389c6e575226f3252fb3cfc7.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 496, + 87, + 692, + 136 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/37e6111293e159bdc603bdbcf8e064a98e848886eeb62eb16b86b68a313bafde.jpg", + "image_caption": [ + "(c) RealFlow" + ], + "image_footnote": [], + "bbox": [ + 496, + 141, + 691, + 189 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/cdb122339af00be3468c779f56d2f6fc76330957cc409b378110940a9c6f6432.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 694, + 87, + 890, + 136 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1d7f34f3b51b136a1c0e0fdcf33da02c40b9882f16a43b71dc527aa19e04c0c2.jpg", + "image_caption": [ + "(d) MPI-Flow (ours)" + ], + "image_footnote": [], + "bbox": [ + 694, + 141, + 890, + 189 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/da6707e7b80286d946ca8c549414289233de634768daf029b1f59ede4fe206b6.jpg", + "image_caption": [ + "Figure 4: Qualitative results of generated images and optical flows from the KITTI 2015 training set. (a) contains the input source images. (b), (c), and (d) contain generated images of RealFlow [12], Depthstillation [1], and our proposed MPI-Flow. MPI-Flow eliminates the artifact in the new image and guarantees image realism. (Best viewed with zoom-in)" + ], + "image_footnote": [], + "bbox": [ + 81, + 291, + 465, + 383 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/81e55a0103cf6eb67b950b31ad9a5cff5ded0d1f816cc7b41613195ae6690ffc.jpg", + "image_caption": [ + "(a) Source Image from KITTI 15", + "(b) Depthstillation" + ], + "image_footnote": [], + "bbox": [ + 83, + 404, + 209, + 496 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/3e09a57c2ded5c79c814a00c1d54c4c332a422696f67ae6ee0144ab751beb139.jpg", + "image_caption": [ + "(c) RealFlow" + ], + "image_footnote": [], + "bbox": [ + 210, + 404, + 336, + 494 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/7831bbf1fc3879e5e55f8195f3f4a80f7a08b71d41b6902bed7c2b671f65460c.jpg", + "image_caption": [ + "(d) MPI-Flow (ours)" + ], + "image_footnote": [], + "bbox": [ + 338, + 404, + 464, + 496 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1caead2e32017dd6cf68a96d50cc32de4eb68d37e269d309d72705545bfab18c.jpg", + "image_caption": [ + "Figure 5: Visualization of generated images with Depthstillation, RealFlow, and our proposed MPI-Flow from KITTI. Note that RealFlow generates such data using two frames with estimated optical flow.", + "(a) Depthstillation", + "Figure 6: Visualization of generated images with Depthstillation and our proposed MPI-Flow using a single view." + ], + "image_footnote": [], + "bbox": [ + 78, + 607, + 259, + 700 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/0ec822264feb48785c74b26e0f1943736703b95cef9bf3c648bb0635ccc43d8f.jpg", + "image_caption": [ + "(b) MPI-Flow (ours)" + ], + "image_footnote": [], + "bbox": [ + 287, + 607, + 467, + 700 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "the same KITTI 15 Train image source, our EPE outperforms the second-best by a remarkable 0.29. When trained and tested with different image sources, our MPI-Flow demonstrates clear improvements over the competitors on almost all the evaluation settings. Notably, MPI-Flow achieves much better performance, even though RealFlow requires two consecutive frames to generate datasets, while", + "bbox": [ + 75, + 794, + 468, + 900 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/dd79828c59fb4a7b2a3f124379025a208f4cd58f372ddf1cbe40f579bd8b04b6.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodKITTI 12KITTI 15
EPE ↓Fl ↓EPE ↓Fl ↓
SemiFlowGAN [25]--{16.02}{38.77}
FlowSupervisor [20]--{3.35}{11.12}
DistractFlow [21]--{3.01}{11.7}
Meta-Learning [36]--{2.81}-
SimFlow [19]--{5.19}-
ARFlow [28]1.44-{2.85}-
UFlow [22]1.68-2.719.05
UpFlow [33]1.27-2.45-
SMURF [42]--{2.00}{6.42}
MPI-Flow1.184.46{1.80}{6.63}
", + "bbox": [ + 504, + 291, + 887, + 460 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 3: Comparison with semi-supervised and unsupervised methods. $\\cdot -$ ’ indicates no results reported.", + "bbox": [ + 500, + 472, + 890, + 502 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "MPI-Flow needs only one still image.", + "bbox": [ + 500, + 534, + 750, + 549 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "It is worth comparing MPI-Flow with Depthstillation under the same settings to evaluate their performance. For this comparison, we use the exact same settings as Depthstillation. Specifically, we generate MPI-Flow datasets with 1) no object motion, 2) the same camera parameters, 3) one camera motion per image, and 4) without pre-training on $\\mathrm{Ch}\\rightarrow \\mathrm{Th}$ . The datasets generated are named MF-DAVIS and MF-COCO, while dCOCO and dDAVIS are generated from Depthstillation. The models are trained from scratch with the respective datasets. RealFlow is not included in this table as it requires a pre-trained optical flow model to generate datasets. The evaluation results are shown in Table 2. Our method outperforms Depthstillation with significant improvements on both COCO and DAVIS, demonstrating the importance of image realism.", + "bbox": [ + 496, + 551, + 890, + 777 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Comparison with Unsupervised Methods. Another way to utilize real-world data is through unsupervised learning, which learns optical flow pixels directly without the need for optical flow labels. In order to further demonstrate the effectiveness of MPI-Flow, we compare our method with the existing literature on unsupervised methods. The results of this comparison can be seen in Table 3. All methods are evaluated under the condition that only images from", + "bbox": [ + 496, + 779, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "13863", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/c7de020e239a8f1a905f622f4c2d8e086680002b141b2e67a5c3a5cb18b53cfc.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Dynamic ObjectsDepth-Aware InpaintingMultiple ObjectsSintel.CSintel.FKITTI 12KITTI 15
EPE ↓>3 ↓EPE ↓>3 ↓EPE ↓Fl ↓EPE ↓Fl ↓
XXX2.586.104.049.671.204.34{2.46}{8.38}
✓XX2.415.393.829.111.264.66{1.88}{7.16}
✓✓X2.375.443.719.051.254.58{1.91}{7.06}
✓✓✓2.205.353.679.031.234.46{1.92}{7.05}
", + "bbox": [ + 138, + 88, + 831, + 175 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/97e88b8580bb192ba47e6b5d2600a7706177521eee13e4f39a36c501ce8c15dd.jpg", + "table_caption": [ + "Table 4: Ablation experiments. Settings used are marked with a checkmark. Here we only perform four camera motions per image for these experiments due to the limitation of computational resources." + ], + "table_footnote": [], + "table_body": "
MethodKITTI 15KITTI 15 test
EPE ↓Fl ↓Fl ↓
PWC-Net [44]{2.16}{9.80}9.60
LiteFlowNet [16]{1.62}{5.58}9.38
IRR-PWC [17]{1.63}{5.32}7.65
RAFT [45]{0.63}{1.50}5.10
Depthstillation [12]---
AutoFlow [43]--4.78
RealFlow [12]{0.58}{1.35}4.63
MPI-Flow{0.58}{1.30}4.58
", + "bbox": [ + 94, + 239, + 454, + 383 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "the evaluation set could be used, without access to ground truth labels. For evaluation, we train the RAFT on our generated dataset with images from the KITTI 15 training set. Our MPI-Flow outperform all unsupervised methods in terms of EPE on both the KITTI 12 training set and KITTI 15 training set, with no need for any unsupervised constraints. However, our method performs better on EPE but has slightly lower F1 than SMURF, mainly because SMURF employs multiple frames for training.", + "bbox": [ + 75, + 453, + 468, + 589 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Comparison with Supervised Methods. To further prove the effectiveness of MPI-Flow, we use KITTI 15 train set to fine-tune RAFT pre-trained by our generated dataset with images from KITTI 15 test set. The evaluation results on KITTI 15 train and KITTI 15 test are shown in Table 5. We achieve state-of-art performance on KITTI 2015 test benchmark compared to supervised methods on training RAFT.", + "bbox": [ + 75, + 590, + 468, + 696 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Qualitative Results. Figure 4 show the generated images from the methods utilizing real-world images, as presented in Table 1. In this comparison, we use images from the KITTI 15 dataset as source image input. The images generated by RealFlow [12] and Depthstillation [1] with artifacts degrade the image realism. In contrast, MPI-Flow generates more realistic images than the other two methods. More results are shown in Figures 5 and 6.", + "bbox": [ + 75, + 696, + 468, + 819 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.4. Discussion", + "text_level": 1, + "bbox": [ + 76, + 830, + 194, + 845 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "To verify the effectiveness of the proposed MPI-Flow, we discuss the performance of models trained with generated datasets with different settings. We show more discus", + "bbox": [ + 76, + 854, + 468, + 900 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/13fd65aa5a0dbc28b04bf071e76da5e2b253653d9d1fef687bbcacaf9b4b0e1e.jpg", + "table_caption": [ + "Table 5: Comparison with supervised methods fine-tuned or trained on KITTI 15 train set." + ], + "table_footnote": [], + "table_body": "
Motions \nPer ImageKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
11.294.582.027.35
41.234.461.927.05
101.214.491.827.02
201.204.411.796.86
401.184.461.806.63
", + "bbox": [ + 552, + 239, + 841, + 340 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/3065d864d59b1bdf0793125027055e2a0c5c857a89a1c50844d89343cc2f18fc.jpg", + "table_caption": [ + "Table 6: Effect of amount of virtual camera motions (training pairs) per source image." + ], + "table_footnote": [], + "table_body": "
Objects \nPer ImageKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
11.254.581.917.06
21.264.762.027.19
41.234.461.927.05
", + "bbox": [ + 552, + 401, + 841, + 474 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 7: Effect of amount of dynamic objects per image.", + "bbox": [ + 508, + 486, + 880, + 501 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "sion and evaluation results in the supplementary material.", + "bbox": [ + 498, + 532, + 879, + 547 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Object Motion and Depth-Aware Inpainting. We conduct a series of ablation studies to analyze the impact of different choices in our proposed MPI-Flow for new image synthesis, including object motion, depth-aware inpainting, and multiple objects. \"Multiple objects\" indicates multiple moving objects in each image. To measure the impact of these factors, we generate new images from the KITTI 15 training set to train RAFT and evaluate them on the KITTI 12 training set and KITTI 15 training set. Because there are multiple combinations of these factors, we test by incrementally adding components of our approach, as shown in Table 4. In the first row, we show the performance achieved by generating new images without dynamic objects, thus assuming that optical flow comes from camera motion only. Then we incrementally add single-object motion, depth-aware inpainting, and multi-object motion to model a more realistic scenario. There are considerable improvements in almost all datasets on various metrics, except for the KITTI 12 training set, possibly due to the infrequent dynamic object motion in this dataset. The EPE on KITTI 15 remains relatively stable within the normal margin after adding the depth-aware inpainting module and the multi-object trick.", + "bbox": [ + 496, + 550, + 890, + 882 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Camera Motion Parameters. We also conduct a series of", + "bbox": [ + 500, + 885, + 890, + 898 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "13864", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/0e04051af9c4f0b1bcf9182430721e7addeff6ffedff803e64813f387f7733e3.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
tzKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
0.1 ~ 0.451.254.60{1.79}{6.68}
0.1 ~ 0.351.184.46{1.80}{6.63}
0.1 ~ 0.251.194.50{1.86}{6.71}
0.0 ~ 0.351.124.32{1.94}{6.92}
", + "bbox": [ + 114, + 88, + 433, + 176 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/63ec7c69827ebbf08456e84b2e4edc9156800a1599776c24549b0ad661e3ee3f.jpg", + "table_caption": [ + "Table 8: Effect of motion parameters ${t}_{z}$ ." + ], + "table_footnote": [], + "table_body": "
txandtyKITTI 12KITTI 15
EPE ↓Fl ↓EPE ↓Fl ↓
-0.3 ~ 0.31.224.42{1.92}{6.83}
-0.2 ~ 0.21.184.46{1.80}{6.63}
-0.1 ~ 0.11.324.99{1.98}{7.02}
", + "bbox": [ + 112, + 217, + 434, + 292 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/cb53a2e0721cf75e78ee1354186e4f7afa520d92494189c31fee3ffc96553aa3.jpg", + "table_caption": [ + "Table 9: Effect of motion parameters ${t}_{x}$ and ${t}_{y}$ ." + ], + "table_footnote": [], + "table_body": "
DatasetKITTI 12KITTI 15
EPE ↓Fl ↓EPE ↓Fl ↓
Ch→Th [18]4.1421.3810.3533.67
dDAVIS [1]2.8111.296.8821.87
MF-DAVIS2.7011.256.9220.97
dCOCO [1]3.1613.308.4926.06
MF-COCO3.0211.208.2223.40
", + "bbox": [ + 112, + 333, + 434, + 435 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "ablation studies to analyze the impact of different parameters on camera motions. We first show the effect of $t_z$ , which indicates the range of moving forward and backward distances, as shown in Table 4. We set the minimum $t_z$ to 0.1 by default, considering that most cameras on vehicles only move forward in the KITTI dataset. We also show the effect of $t_x$ and $t_y$ , representing the distance from left to right and from up to down, respectively. Because there are multiple combinations of parameters, we only test a specific parameter of our method in isolation. Settings used by default are underlined. The results show that a more reasonable range of camera motion leads to better performance.", + "bbox": [ + 75, + 505, + 467, + 686 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Model Architectures The default model used in our paper is RFAT [45]. Table 10 shows that our proposed MPI-Flow also works for PWC-Net [44] compared with depthstillation [1] in a fair setting. We generate data from COCO and DAVIS and train PWC-Net, in which the results are still better than PWC-Net trained on $\\mathrm{Ch} \\rightarrow \\mathrm{Th}$ or datasets generated from depthstillation.", + "bbox": [ + 75, + 686, + 467, + 792 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Amount of Virtual Motions. We can generate multiple camera motions with multiple dynamic objects for any given single image and thus a variety of paired images and ground-truth optical flow maps. Thus we can increase the number of camera motions to generate more data. Table 6 shows the impact of different amounts of camera motions on model performance. Interestingly, MPI-Flow with 4 mo", + "bbox": [ + 75, + 794, + 467, + 900 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/394650d0014f127dd0cb922a5c93d298c0518fd07fb51481ea8c9bc79fbe667a.jpg", + "table_caption": [ + "Table 10: Results on PWC-Net trained on generated datasets from scratch under the same setting." + ], + "table_footnote": [], + "table_body": "
DatasetQuantityKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
Ch→Th [18]47K2.088.865.0017.44
MF-COCO20K1.596.223.6811.95
MF-COCO120K1.515.943.4111.16
", + "bbox": [ + 504, + 88, + 888, + 162 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 11: Effect of amount of source images.", + "bbox": [ + 544, + 172, + 843, + 186 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "tions per image already allows for strong generalization to real domains, outperforming the results achieved using synthetic datasets shown in the previous evaluation results. Increasing the motions per image by factors 10 and 20 both lead to better performance on KITTI 12 and KITTI 15 compared to 4 and 1. Using 40 motions per image gives the best performance on KITTI 15 in terms of Fl. It indicates that a more variegate image content in the generated dataset may be beneficial for generalization to real applications. Table 7 shows the effect of amounts of dynamic objects on model performance. Increasing the number of dynamic objects improves the performance of the model on KITTI 12 but slightly decreases it on KITTI 15 in terms of EPE.", + "bbox": [ + 496, + 217, + 890, + 412 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Quantity of Source Images The number of source images affects the scene diversity of the generated dataset. Empirically, more source images will be more conducive to model learning, as verified in Table 11. We verify the effect of the number of source images on the MF-COCO. The model performance is significantly improved by increasing the number of source images.", + "bbox": [ + 496, + 414, + 890, + 520 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 537, + 617, + 553 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this paper, we present a new framework for generating optical flow datasets, which addresses two main challenges: image realism and motion realism. Firstly, we propose an MPI-based image rendering pipeline that generates realistic images with corresponding optical flows from novel viewpoints. This pipeline utilizes volume rendering to address image artifacts and holes, leading to more realistic images. Secondly, we introduce an independent object motion module that separates dynamic objects from the static scene. By decoupling object motion, we further improve motion realism. Additionally, we design a depth-aware inpainting module that handles unnatural occlusions caused by object motion in the generated images. Through these novel designs, our approach achieves superior performance on real-world datasets compared to both unsupervised and supervised methods for training learning-based models.", + "bbox": [ + 496, + 564, + 890, + 804 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgments This work was supported by the National Natural Science Foundation of China (12202048, 62171038, and 62171042), the R&D Program of Beijing Municipal Education Commission (KZ202211417048), and the Fundamental Research Funds for the Central Universities.", + "bbox": [ + 496, + 809, + 890, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "13865", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Filippo Aleotti, Matteo Poggi, and Stefano Mattoccia. Learning optical flow from still images. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 15201-15211, 2021. 1, 2, 3, 5, 6, 7, 8, 9", + "[2] Simon Baker, Daniel Scharstein, JP Lewis, Stefan Roth, Michael J Black, and Richard Szeliski. A database and evaluation methodology for optical flow. International Journal of Computer Vision (IJCV), 92(1):1-31, 2011. 1, 2", + "[3] Thomas Brox, Christoph Bregler, and Jitendra Malik. Large displacement optical flow. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 41-48, 2009. 1", + "[4] D. J. Butler, J. Wulff, G. B. Stanley, and M. J. Black. A naturalistic open source movie for optical flow evaluation. In the European Conference on Computer Vision (ECCV), pages 611-625, 2012. 1", + "[5] Daniel J Butler, Jonas Wulff, Garrett B Stanley, and Michael J Black. A naturalistic open source movie for optical flow evaluation. In the European Conference on Computer Vision (ECCV), pages 611-625, 2012. 5", + "[6] Gustavo Sutter P. Carvalho, Diogo Carbonera Luvizon, Antonio Joia Neto, Andre G. C. Pacheco, and Otavio Augusto Bizetto Penatti. Learning multiplane images from single views with self-supervision. In British Machine Vision Conference (BMVC), 2021. 2", + "[7] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1290–1299, 2022. 4", + "[8] Jiyu Cheng, Yuxiang Sun, and Max Q-H Meng. Improving monocular visual slam in dynamic environments: an optical-flow-based approach. Advanced Robotics, 33(12):576-589, 2019. 1", + "[9] Alexey Dosovitskiy, Philipp Fischer, Eddy Ilg, Philip Hausser, Caner Hazirbas, Vladimir Golkov, Patrick Van Der Smagt, Daniel Cremers, and Thomas Brox. Flownet: Learning optical flow with convolutional networks. In the IEEE International Conference on Computer Vision (ICCV), pages 2758-2766, 2015. 1, 2, 5", + "[10] Bo Du, Shihan Cai, and Chen Wu. Object tracking in satellite videos based on a multiframe optical flow tracker (j-stars). the IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 12(8):3043-3055, 2019. 1", + "[11] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the kitti vision benchmark suite. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3354-3361, 2012. 1, 2, 5", + "[12] Yunhui Han, Kunming Luo, Ao Luo, Jiangyu Liu, Haoqiang Fan, Guiming Luo, and Shuaicheng Liu. Realflow: Embased realistic optical flow dataset generation from videos. In the European Conference on Computer Vision (ECCV), pages 288-305, 2022. 1, 2, 3, 5, 6, 7, 8", + "[13] Yuxuan Han, Ruicheng Wang, and Jiaolong Yang. Single-view synthesis in the wild with learned adaptive multiplane images. In ACM SIGGRAPH, 2022. 2, 3, 4" + ], + "bbox": [ + 78, + 114, + 470, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[14] Toshihide Hanari, Kuniaki Kawabata, and Keita Nakamura. Image selection method from image sequence to improve computational efficiency of 3d reconstruction: Analysis of inter-image displacement based on optical flow for evaluating 3d reconstruction performance. In the IEEE International Symposium on System Integration (SII), pages 1041-1045, 2022. 1", + "[15] Anders Heyden and Marc Pollefeys. Multiple view geometry. Emerging topics in computer vision, 3:45-108, 2005. 4", + "[16] Tak-Wai Hui, Xiaou Tang, and Chen Change Loy. Liteflownet: A lightweight convolutional neural network for optical flow estimation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 8981-8989, 2018. 2, 8", + "[17] Junhwa Hur and Stefan Roth. Iterative residual refinement for joint optical flow and occlusion estimation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 5754-5763, 2019. 2, 8", + "[18] Eddy Ig, Nikolaus Mayer, Tonmoy Saikia, Margret Keuper, Alexey Dosovitskiy, and Thomas Brox. Flownet 2.0: Evolution of optical flow estimation with deep networks. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 2462-2470, 2017. 1, 2, 5, 6, 9", + "[19] Woobin Im, Tae-Kyun Kim, and Sung-Eui Yoon. Unsupervised learning of optical flow with deep feature similarity. In the European Conference on Computer Vision (ECCV), pages 172-188, 2020. 7", + "[20] Woobin Im, Sebin Lee, and Sung-Eui Yoon. Semi-supervised learning of optical flow by flow supervisor. In the European Conference on Computer Vision (ECCV), pages 302-318, 2022. 7", + "[21] Jisoo Jeong, Hong Cai, Risheek Garrepalli, and Fatih Porikli. Distractflow: Improving optical flow estimation via realistic distractions and pseudo-labeling. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 13691-13700, 2023. 7", + "[22] Rico Jonschkowski, Austin Stone, Jonathan T Barron, Ariel Gordon, Kurt Konolige, and Anelia Angelova. What matters in unsupervised optical flow. In the European Conference on Computer Vision (ECCV), pages 557-572, 2020. 7", + "[23] Artúr I Károly, Renata Nagyné Elek, Tamás Haidegger, Károly Széll, and Péter Galambos. Optical flow-based segmentation of moving objects for mobile robot navigation using pre-trained deep learning models. In the IEEE International Conference on Systems, Man and Cybernetics (SMC), pages 3080-3086, 2019. 1", + "[24] Filippos Kokkinos and Iasonas Kokkinos. Learning monocular 3d reconstruction of articulated categories from motion. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1737-1746, 2021. 1", + "[25] Wei-Sheng Lai, Jia-Bin Huang, and Ming-Hsuan Yang. Semi-supervised learning for optical flow with generative adversarial networks. Advances in Neural Information Processing Systems (NIPS), 30, 2017. 7", + "[26] Jiaxin Li, Zijian Feng, Qi She, Henghui Ding, Changhu Wang, and Gim Hee Lee. Mine: Towards continuous depth" + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "13866", + "bbox": [ + 480, + 945, + 519, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "MPI with nerf for novel view synthesis. In the IEEE International Conference on Computer Vision (ICCV), pages 12578-12588, 2021. 3", + "[27] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In the European Conference on Computer Vision (ECCV), pages 740-755, 2014. 5", + "[28] Liang Liu, Jiangning Zhang, Ruifei He, Yong Liu, Yabiao Wang, Ying Tai, Donghao Luo, Chengjie Wang, Jilin Li, and Feiyue Huang. Learning by analogy: Reliable supervision from transformations for unsupervised optical flow estimation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 6489-6498, 2020. 7", + "[29] Yubao Liu and Jun Miura. Rdmo-slam: Real-time visual slam for dynamic environments using semantic label prediction with optical flow. IEEE Access, 9:106981-106997, 2021. 1", + "[30] Stephen Lombardi, Tomas Simon, Jason Saragih, Gabriel Schwartz, Andreas Lehrmann, and Yaser Sheikh. Neural volumes: Learning dynamic renderable volumes from images. arXiv preprint arXiv:1906.07751, 2019. 2", + "[31] Ao Luo, Fan Yang, Xin Li, and Shuaicheng Liu. Learning optical flow with kernel patch attention. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 8906-8915, 2022. 2", + "[32] Ao Luo, Fan Yang, Kunming Luo, Xin Li, Haoqiang Fan, and Shuaicheng Liu. Learning optical flow with adaptive graph reasoning. In the AAAI Conference on Artificial Intelligence, volume 36, pages 1890-1898, 2022. 2", + "[33] Kunming Luo, Chuan Wang, Shuaicheng Liu, Haoqiang Fan, Jue Wang, and Jian Sun. Upflow: Upsampling pyramid for unsupervised optical flow learning. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1045-1054, 2021. 7", + "[34] Moritz Menze and Andreas Geiger. Object scene flow for autonomous vehicles. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3061-3070, 2015. 1, 2, 5", + "[35] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021. 2", + "[36] Chaerin Min, Taehyun Kim, and Jongwoo Lim. Meta-learning for adaptation of deep optical flow networks. In the IEEE Winter Conference on Applications of Computer Vision (WACV), pages 2145-2154, 2023. 7", + "[37] Federico Perazzi, Jordi Pont-Tuset, Brian McWilliams, Luc Van Gool, Markus Gross, and Alexander Sorkine-Hornung. A benchmark dataset and evaluation methodology for video object segmentation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 724-732, 2016. 5", + "[38] René Ranftl, Katrin Lasinger, David Hafner, Konrad Schindler, and Vladlen Koltun. Towards robust monocular depth estimation: Mixing datasets for zero-shot cross-dataset" + ], + "bbox": [ + 78, + 92, + 468, + 900 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "transfer. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 44(3):1623-1637, 2020. 4", + "[39] Chris Rockwell, David F Fouhey, and Justin Johnson. Pixelsynth: Generating a 3d-consistent experience from a single image. In the IEEE International Conference on Computer Vision (ICCV), pages 14104-14113, 2021. 3", + "[40] Robin Rombach, Patrick Esser, and Björn Ommer. Geometry-free view synthesis: Transformers and no 3d priors. In the IEEE International Conference on Computer Vision (ICCV), pages 14356-14366, 2021. 3", + "[41] Nitin J Sanket, Chahat Deep Singh, Cornelia Fermüller, and Yiannis Aloimonos. Prgflow: Unified swap-aware deep global optical flow for aerial robot navigation. *Electronics Letters*, 57(16):614–617, 2021. 1", + "[42] Austin Stone, Daniel Maurer, Alper Ayvaci, Anelia Angelova, and Rico Jonschkowski. Smurf: Self-teaching multiframe unsupervised raft with full-image warping. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3887-3896, 2021. 7", + "[43] Deqing Sun, Daniel Vlasic, Charles Herrmann, Varun Jampani, Michael Krainin, Huiwen Chang, Ramin Zabih, William T Freeman, and Ce Liu. Autoflow: Learning a better training set for optical flow. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 10093-10102, 2021. 2, 8", + "[44] Deqing Sun, Xiaodong Yang, Ming-Yu Liu, and Jan Kautz. Pwc-net: Cnns for optical flow using pyramid, warping, and cost volume. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 8934-8943, 2018. 1, 2, 8, 9", + "[45] Zachary Teed and Jia Deng. Raft: Recurrent all-pairs field transforms for optical flow. In the European Conference on Computer Vision (ECCV), pages 402-419, 2020. 1, 2, 5, 8, 9", + "[46] Alexandru Telea. An image inpainting technique based on the fast marching method. Journal of graphics tools, 9(1):23-34, 2004. 4", + "[47] Richard Tucker and Noah Snively. Single-view view synthesis with multiplane images. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 551-560, 2020. 2, 3", + "[48] Shubham Tulsiani, Richard Tucker, and Noah Snavely. Layer-structured 3d scene inference via view synthesis. In the European Conference on Computer Vision (ECCV), pages 302–317, 2018. 2", + "[49] Philippe Weinzaepfel, Jerome Revaud, Zaid Harchaoui, and Cordelia Schmid. Deepflow: Large displacement optical flow with deep matching. In the IEEE International Conference on Computer Vision (ICCV), pages 1385-1392, 2013. 1, 2", + "[50] Christopher Zach, Thomas Pock, and Horst Bischof. A duality based approach for realtime tv-l 1 optical flow. In Pattern Recognition, pages 214-223, 2007. 1", + "[51] Jimuyang Zhang, Sanping Zhou, Xin Chang, Fangbin Wan, Jinjun Wang, Yang Wu, and Dong Huang. Multiple object tracking by flowing and fusing. arXiv preprint arXiv:2001.11180, 2020. 1", + "[52] Tianwei Zhang, Huayan Zhang, Yang Li, Yoshihiko Nakamura, and Lei Zhang. Flowfusion: Dynamic dense rgb-d" + ], + "bbox": [ + 503, + 92, + 890, + 900 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "13867", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "slam based on optical flow. In the IEEE International Conference on Robotics and Automation (ICRA), pages 7322-7328, 2020. 1", + "[53] Tinghui Zhou, Richard Tucker, John Flynn, Graham Fyffe, and Noah Snavely. Stereo magnification: Learning view synthesis using multiplane images. In ACM SIGGRAPH, 2018. 2", + "[54] Yuemei Zhou, Gaochang Wu, Ying Fu, Kun Li, and Yebin Liu. Cross-mpi: Cross-scale stereo for image super-resolution using multiplane images. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 14842-14851, 2021. 2" + ], + "bbox": [ + 78, + 90, + 468, + 258 + ], + "page_idx": 11 + }, + { + "type": "page_number", + "text": "13868", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 11 + } +] \ No newline at end of file diff --git a/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/d01da3cc-92b1-43b1-b6d0-867a68823626_model.json b/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/d01da3cc-92b1-43b1-b6d0-867a68823626_model.json new file mode 100644 index 0000000000000000000000000000000000000000..bd4470f97c3ec7139453da2f56950c18ad1f87c9 --- /dev/null +++ b/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/d01da3cc-92b1-43b1-b6d0-867a68823626_model.json @@ -0,0 +1,2776 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.142, + 0.131, + 0.83, + 0.154 + ], + "angle": 0, + "content": "MPI-Flow: Learning Realistic Optical Flow with Multiplane Images" + }, + { + "type": "text", + "bbox": [ + 0.146, + 0.18, + 0.28, + 0.2 + ], + "angle": 0, + "content": "Yingping Liang" + }, + { + "type": "text", + "bbox": [ + 0.361, + 0.181, + 0.466, + 0.199 + ], + "angle": 0, + "content": "Jiaming Liu2" + }, + { + "type": "text", + "bbox": [ + 0.273, + 0.2, + 0.528, + 0.218 + ], + "angle": 0, + "content": "1Beijing Institute of Technology" + }, + { + "type": "text", + "bbox": [ + 0.546, + 0.181, + 0.668, + 0.199 + ], + "angle": 0, + "content": "Debing Zhang" + }, + { + "type": "text", + "bbox": [ + 0.548, + 0.2, + 0.698, + 0.217 + ], + "angle": 0, + "content": "\\(^{2}\\)Xiaohongshu Inc." + }, + { + "type": "text", + "bbox": [ + 0.75, + 0.181, + 0.83, + 0.199 + ], + "angle": 0, + "content": "Ying Fu\\(^{1*}\\)" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.251, + 0.314, + 0.267 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.285, + 0.474, + 0.753 + ], + "angle": 0, + "content": "The accuracy of learning-based optical flow estimation models heavily relies on the realism of the training datasets. Current approaches for generating such datasets either employ synthetic data or generate images with limited realism. However, the domain gap of these data with real-world scenes constrains the generalization of the trained model to real-world applications. To address this issue, we investigate generating realistic optical flow datasets from real-world images. Firstly, to generate highly realistic new images, we construct a layered depth representation, known as multiplane images (MPI), from single-view images. This allows us to generate novel view images that are highly realistic. To generate optical flow maps that correspond accurately to the new image, we calculate the optical flows of each plane using the camera matrix and plane depths. We then project these layered optical flows into the output optical flow map with volume rendering. Secondly, to ensure the realism of motion, we present an independent object motion module that can separate the camera and dynamic object motion in MPI. This module addresses the deficiency in MPI-based single-view methods, where optical flow is generated only by camera motion and does not account for any object movement. We additionally devise a depth-aware inpainting module to merge new images with dynamic objects and address unnatural motion occlusions. We show the superior performance of our method through extensive experiments on real-world datasets. Moreover, our approach achieves state-of-the-art performance in both unsupervised and supervised training of learning-based models. The code will be made publicly available at: https://github.com/Sharpiless/MPI-Flow." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.786, + 0.21, + 0.801 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.812, + 0.47, + 0.874 + ], + "angle": 0, + "content": "Optical flow refers to the precise calculation of per-pixel motion between consecutive video frames. Its applications span a wide range of fields, including object tracking [10, 51], robot navigation [23, 41], three-dimensional (3D)" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.25, + 0.629, + 0.356 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.511, + 0.362, + 0.621, + 0.375 + ], + "angle": 0, + "content": "(a) Depthstill. [1]" + }, + { + "type": "image", + "bbox": [ + 0.635, + 0.25, + 0.761, + 0.357 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.642, + 0.362, + 0.753, + 0.375 + ], + "angle": 0, + "content": "(b) RealFlow [12]" + }, + { + "type": "image", + "bbox": [ + 0.765, + 0.25, + 0.892, + 0.356 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.801, + 0.362, + 0.856, + 0.375 + ], + "angle": 0, + "content": "(c) Ours" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.375, + 0.766, + 0.493 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.503, + 0.498, + 0.89, + 0.512 + ], + "angle": 0, + "content": "(d) Source image and details of generated flows from our method" + }, + { + "type": "image", + "bbox": [ + 0.766, + 0.376, + 0.89, + 0.493 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.524, + 0.894, + 0.616 + ], + "angle": 0, + "content": "Figure 1: Visual comparison of images reveals that our method, when compared with those based on real-world images [1, 12], demonstrates superior image realism. Our method also achieves fine optical flows by employing volume rendering in MPI and separate motions of the camera and object with the independent object motion module." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.643, + 0.894, + 0.795 + ], + "angle": 0, + "content": "reconstruction [24, 14], and visual simultaneous localization and mapping (SLAM) [52, 8, 29]. In recent years, with the rapid development of neural networks, learning-based methods [44, 45] have demonstrated significant advances compared to traditional model-based algorithms [3, 49, 50]. Conventional practices primarily rely on synthetic data, as demonstrated by [9, 18, 4]. Synthetic data contains exact optical flow labels and animated images. However, the domain gap between synthetic and real data hinders its further improvements in real-world applications." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.894, + 0.901 + ], + "angle": 0, + "content": "Recent studies have aimed to extract optical flow from real-world data by employing hand-made special hardware [2, 11, 34]. However, the rigidly controlled and inefficient collection procedure limits their applicability. To address this issue, Depthstillation [1], and RealFlow [12] have been proposed, which project each pixel in the real-world image onto the novel view frame with the help of random motions" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.329, + 0.9 + ], + "angle": 0, + "content": "*Corresponding Author: fuying@bit.edu.cn" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13857" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.167 + ], + "angle": 0, + "content": "of virtual cameras or estimated flows. Nonetheless, both methods are limited by the lack of image realism, leading to issues such as collisions, holes, and artifacts, as illustrated in Figure 1. These limitations constrain the real-world performance of learning-based optical flow models [44, 45]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.168, + 0.47, + 0.317 + ], + "angle": 0, + "content": "To achieve higher image realism, we turn our attention to the use of single-view Multiplane Images (MPI) [53, 47, 54, 6, 13]. This line of work demonstrates remarkable single-view image rendering capabilities and effectively reduces collisions, holes, and artifacts commonly found in previous methods [1, 12]. These advancements contribute to higher image realism, prompting a natural question: Can high-realistic MPI methods be adapted to generate high-quality optical flow datasets for training purposes?" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.318, + 0.471, + 0.604 + ], + "angle": 0, + "content": "To this end, we propose MPI-Flow, aiming to generate realistic optical flow datasets from real-world images. Specifically, we first review the image synthesis pipeline of MPI and devise an optical flow generation pipeline along with image synthesis. In this step, we build an MPI by warping single-view image features onto each layered plane with the predicted color and density. The color and density then be mapped into a realistic new image via volume rendering. With the layered planes, we extract optical flows with virtual camera motions from the rendered image and the real image. Second, as the MPI can only be applied in static scenes, which yield limited motion realism, we propose an independent object motion module and a depth-aware inpainting module to tackle this issue. The independent object motion module decouples dynamic objects from static scenes and applies different virtual camera matrices to calculate the motion of both dynamic and static parts. The depth-aware inpainting module is introduced to remove the object occlusion in the synthesized new image." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.605, + 0.47, + 0.71 + ], + "angle": 0, + "content": "With MPI-Flow, a large number of single-view images can be used to generate large-scale training datasets with realistic images and motions. This enables learning-based optical flow models better generalization to a wide range of real-world scenes. Extensive experiments on real datasets demonstrate the effectiveness of our approach. In summary, our main contributions are as follows:" + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.718, + 0.468, + 0.779 + ], + "angle": 0, + "content": "- We are the first to present a novel MPI-based optical flow dataset generation framework, namely MPI-Flow, which can significantly improve the realism of the generated images and motion." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.787, + 0.468, + 0.847 + ], + "angle": 0, + "content": "- We present a novel independent object motion module for modeling dynamic objects in MPI, which can model realistic optical flow from camera motion and object motion simultaneously." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.856, + 0.468, + 0.901 + ], + "angle": 0, + "content": "- We design a depth-aware inpainting module for realistic image inpainting, which can remove unnatural motion occlusions in generated images." + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.718, + 0.468, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.09, + 0.642, + 0.105 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.116, + 0.892, + 0.16 + ], + "angle": 0, + "content": "In this section, we review the most relevant studies on optical flow networks, optical flow dataset generation, and novel view image synthesis methods." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.161, + 0.892, + 0.341 + ], + "angle": 0, + "content": "Supervised Optical Flow Network. Early methods train deep neural networks to match patches across images [49]. FlowNet [9] first trains convolutional neural networks on the synthetic datasets with optical flow. Moreover, the follow-up methods [16, 17, 18, 32, 31] with advanced modules and network architectures make a significant improvement in supervised optical flow learning, with RAFT [45] representing state-of-the-art. However, generalization remains a cause for concern due to the domain gap between synthetic datasets and real-world applications. To address this problem, our work focuses on generating realistic optical flow datasets from real-world images." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.342, + 0.892, + 0.598 + ], + "angle": 0, + "content": "Dataset Generation for Optical Flow. The use of fluorescent texture to record motions in real-world scenes is first described in [2] to obtain flow maps. KITTI [11, 34] provides sophisticated training data through complex lidar and camera setups. However, the aforementioned real-world datasets have limited quantities and constrained scenes, making it difficult for models trained using deep supervised learning to generalize to more expansive scenes. Synthesized training pairs, such as those in Flyingchairs [9] and Flyingthings [18], have shown promise for supervised learning. However, moving animated image patches cannot accurately match real-world scenes, leading to domain gaps. AutoFlow [43] introduces a learning-based approach for generating training data by hyper-parameters searching. However, AutoFlow relies on optical flow labels for domain adaptation, which is not practical in most scenarios where ground truth labels are unavailable." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.6, + 0.892, + 0.794 + ], + "angle": 0, + "content": "Two recent works have proposed methods for generating training datasets based on real-world images or videos. The first, called Depthstillation [1], synthesizes paired images by estimating depth and optical flows from a single still image. Optical flows are calculated based on the virtual camera pose and depth. The second method, called RealFlow [12], synthesizes intermediate frames between two frames using estimated optical flows with RAFT. However, both methods use naive image synthesis techniques that fail to meet the demand for realism criteria due to hole-filling and artifacts. In contrast, our method improves on this approach by using a well-designed and modified multiplane image (MPI) technique to obtain realistic images." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.796, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Novel View Synthesis. View synthesis methods aim to generate new images from arbitrary viewpoints by utilizing a given scene. Several classical approaches [48, 30, 53, 35] have been proposed that utilize multiple views of a scene to render novel views with geometric consistency. However, synthesizing novel views from a single image remains challenging due to the limited scene information available." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13858" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.102, + 0.092, + 0.868, + 0.391 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.414, + 0.896, + 0.477 + ], + "angle": 0, + "content": "Figure 2: Illustration of our proposed MPI-Flow framework with single-view image \\(\\mathbf{I}_s\\) as input. We estimate depths to construct MPI where RGB and density of each plane are predicted by neural networks and the flow of each plane is calculated with camera matrixes. Both the novel views and flow maps are rendered by volume rendering and separated by the independent object motion module with novel view object masks. The new image is merged by depth-aware inpainting." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.501, + 0.473, + 0.82 + ], + "angle": 0, + "content": "Pixelsynth [39] and Geometry-Free View Synthesis [40] address this challenge by optimizing the synthesizing model using multi-view supervision. However, their generalization to in-the-wild scenes is hindered by the lack of large-scale multi-view datasets. Single-view MPI [47] and MINE [26] decompose the scene into multiple layers and utilize an inpainting network to extend each occluded layer. Additionally, AdaMPI [13] addresses complex 3D scene structures through a novel plane adjustment network. These MPI-based methods have demonstrated success in synthesizing realistic images, and thus, we adopt multiplane images as our basic synthesis tool. However, to the best of our knowledge, there are currently no publicly available methods for generating optical flow datasets from MPI. To extract optical flows from MPI, we propose a novel pipeline that differs from previous MPI-based image synthesis methods by utilizing layered depths and virtual camera poses. Additionally, to enhance the realism of the generated optical flow dataset, we introduce an independent object motion module for static and dynamic decoupling, as well as a depth-aware inpainting module to remove unnatural occupations." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.83, + 0.31, + 0.848 + ], + "angle": 0, + "content": "3. The Proposed MPI-Flow" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.471, + 0.903 + ], + "angle": 0, + "content": "In this section, we first briefly review the basics of our motivation and formulation for novel view image generation. Then we introduce the optical flow generation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.501, + 0.893, + 0.548 + ], + "angle": 0, + "content": "pipeline. Next, we present the details of two crucial components of our approach, including independent object motions and depth-aware inpainting." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.559, + 0.757, + 0.573 + ], + "angle": 0, + "content": "3.1. Motivation and Formulation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.583, + 0.892, + 0.704 + ], + "angle": 0, + "content": "Our goal is to generate a realistic novel view image \\(\\mathbf{I}_t\\in \\mathbb{R}^{H\\times W\\times 3}\\) and the corresponding optical flow maps \\(\\mathbf{F}_{s\\rightarrow t}\\in \\mathbb{R}^{H\\times W\\times 2}\\) from single-view image \\(\\mathbf{I}_s\\in \\mathbb{R}^{H\\times W\\times 3}\\). \\(H\\) and \\(W\\) are the height and width of the image, respectively. The two-dimensional array on the optical flow \\(\\mathbf{F}_{s\\rightarrow t}\\) represents the change of the corresponding pixel from image \\(\\mathbf{I}_s\\) to image \\(\\mathbf{I}_t\\). The input image, generated image, and optical flow together form a training pair." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.892, + 0.81 + ], + "angle": 0, + "content": "To generate training pair, previous works [1, 12] wrap pixels from image \\(\\mathbf{I}_s\\) to image \\(\\mathbf{I}_t\\) with estimated flows. This inevitably leads to holes and artifacts in the image \\(\\mathbf{I}_t\\), which damages the image realism. Recent work [47, 26, 13] on Multiplane Images (MPI) reveals that the layered depth representation of the single-view image can significantly improve the realism of the generated novel view image." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.893, + 0.902 + ], + "angle": 0, + "content": "We aim to tackle the image realism challenges in our methods and meanwhile enhance the optical flow realism and motion realism. Accordingly, we present an MPI-based optical flow dataset generation method, namely MPI-Flow. Figure 2 shows the MPI-Flow framework for training pair generation. To construct MPI, given the input image \\(\\mathbf{I}_s\\)," + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "13859" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.167 + ], + "angle": 0, + "content": "an off-the-shelf monocular depth estimation network [38] is used to estimate its depth map. Then we use a neural network to construct \\(N\\) fronto-parallel RGB\\(\\sigma\\) planes with color, density, and depth predicted by neural networks in the rays under novel viewpoints." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.168, + 0.471, + 0.364 + ], + "angle": 0, + "content": "To decouple dynamic objects, an instance segmentation network [7] gives the object mask. Then we use bilinear interpolation to obtain the object masks under two viewpoints respectively. Using object masks and constructed MPI, we use volume rendering to render the separate novel view images, optical flow maps, and depths of dynamic objects and the static scene, respectively. The optical flow \\(\\mathbf{F}_{s\\rightarrow t}\\) can be obtained simply by adding the optical flows of the objects and the scene. However, due to different viewpoints, merging new images results in vacant areas and false occlusion. To this end, we design a depth-aware inpainting module, using rendered depths and object masks to fill the holes and repair false occlusion in the synthesized new image \\(\\mathbf{I}_t\\)" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.372, + 0.347, + 0.388 + ], + "angle": 0, + "content": "3.2. Optical Flow Data Generation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.395, + 0.47, + 0.501 + ], + "angle": 0, + "content": "Novel View Image from MPI. To render realistic image \\(\\mathbf{I}_t\\) under a target viewpoint \\(\\pmb{\\mu}_t\\), we use pixel warping from the source-view MPI in a differentiable manner. Specifically, we use a neural network \\(\\mathcal{F}\\) as in [13] to construct \\(N\\) frontoparallel RGB \\(\\sigma\\) planes under source viewpoint \\(\\pmb{\\mu}_s\\) with color channels \\(\\mathbf{c}_n\\), density channel \\(\\sigma_n\\), and depth \\(\\mathbf{d}_n\\) from the input image \\(\\mathbf{I}_s\\) and its depth map \\(\\mathbf{D}_s\\) as:" + }, + { + "type": "equation", + "bbox": [ + 0.164, + 0.509, + 0.469, + 0.528 + ], + "angle": 0, + "content": "\\[\n\\left\\{\\left(\\mathbf {c} _ {n}, \\boldsymbol {\\sigma} _ {n}, \\mathbf {d} _ {n}\\right) \\right\\} _ {n = 1} ^ {N} = \\mathcal {F} \\left(\\mathbf {I} _ {s}, \\mathbf {D} _ {s}\\right), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.537, + 0.469, + 0.598 + ], + "angle": 0, + "content": "where \\(N\\) is a predefined parameter that represents the number of planes in MPI. Each pixel \\((x_{t},y_{t})\\) on the novel view image plane can be mapped to pixel \\((x_{s},y_{s})\\) on \\(n\\)-th source MPI plane via homography function [15]:" + }, + { + "type": "equation", + "bbox": [ + 0.116, + 0.605, + 0.469, + 0.64 + ], + "angle": 0, + "content": "\\[\n\\left[ x _ {s}, y _ {s}, 1 \\right] ^ {T} \\sim \\mathbf {K} \\left(\\mathbf {R} - \\frac {\\mathbf {t n} ^ {T}}{\\mathbf {d} _ {n}}\\right) \\mathbf {K} ^ {- 1} \\left[ x _ {t}, y _ {t}, 1 \\right] ^ {T}, \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.648, + 0.469, + 0.754 + ], + "angle": 0, + "content": "where \\(\\mathbf{R}\\) and \\(\\mathbf{t}\\) are the rotation and translation from the source viewpoints \\(\\pmb{\\mu}_{s}\\) to the target viewpoints \\(\\pmb{\\mu}_{t}\\), \\(\\mathbf{K}\\) is the camera intrinsic, and \\(\\mathbf{n} = [0,0,1]\\) is the normal vector. Thus, the color \\(\\mathbf{c}_n^\\prime\\) and density \\(\\sigma_{n}^{\\prime}\\) of each new plane for the novel view \\(\\mathbf{I}_t\\) can be obtained via bilinear sampling. We use discrete intersection points between new planes and arbitrary rays passing through the scene and estimate integrals:" + }, + { + "type": "equation", + "bbox": [ + 0.154, + 0.764, + 0.469, + 0.806 + ], + "angle": 0, + "content": "\\[\n\\mathbf {I} _ {t} = \\sum_ {n = 1} ^ {N} \\left(\\mathbf {c} _ {n} ^ {\\prime} \\boldsymbol {\\alpha} _ {n} ^ {\\prime} \\prod_ {m = 1} ^ {n - 1} \\left(1 - \\boldsymbol {\\alpha} _ {m} ^ {\\prime}\\right)\\right), \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.469, + 0.856 + ], + "angle": 0, + "content": "where \\(\\alpha_{n}^{\\prime} = \\exp \\left(-\\delta_{n}\\sigma_{n}^{\\prime}\\right)\\) and \\(\\delta_{n}\\) is the distance map between plane \\(n\\) and \\(n + 1\\) and we set the initial depth of MPI planes uniformly spaced in disparity as in [13]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.871, + 0.469, + 0.902 + ], + "angle": 0, + "content": "Optical Flow from MPI. Although MPI-based methods synthesize realistic images, reliable optical flow maps are" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.183 + ], + "angle": 0, + "content": "also needed to train learning-based optical flow estimation models. Therefore, we propose adding an additional optical channel in each plane. To this end, we compute the optical flow on the \\(n\\)-th plane at pixel \\([x_s, y_s]\\) of source image \\(\\mathbf{I}_s\\) by \\(\\mathbf{f}_n = [x_t - x_s, y_t - y_s]\\) with a backward-warp process in terms of the inverse equivalent form of Equation (2):" + }, + { + "type": "equation", + "bbox": [ + 0.522, + 0.194, + 0.892, + 0.23 + ], + "angle": 0, + "content": "\\[\n\\left[ x _ {t}, y _ {t}, 1 \\right] ^ {T} \\sim \\mathbf {K} \\left(\\mathbf {R} ^ {\\dagger} - \\frac {\\mathbf {t} ^ {\\dagger} \\mathbf {n} ^ {T}}{\\mathbf {d} _ {n}}\\right) \\mathbf {K} ^ {- 1} \\left[ x _ {s}, y _ {s}, 1 \\right] ^ {T}, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.24, + 0.89, + 0.27 + ], + "angle": 0, + "content": "where \\(x_{s}\\) and \\(y_{s}\\) are uniformly sampled from a \\(H\\times W\\) grid. \\(\\mathbf{R}^{\\dagger}\\) and \\(\\mathbf{t}^{\\dagger}\\) are the inverses of \\(\\mathbf{R}\\) and \\(\\mathbf{t}\\), respectively." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.271, + 0.892, + 0.317 + ], + "angle": 0, + "content": "To make sure that the optical flow maps match the novel view image \\(\\mathbf{I}_t\\) perfectly, we propose to render \\(\\mathbf{F}_{s\\rightarrow t}\\) as in Equation (3) in terms of volume rendering:" + }, + { + "type": "equation", + "bbox": [ + 0.566, + 0.329, + 0.892, + 0.371 + ], + "angle": 0, + "content": "\\[\n\\mathbf {F} _ {s \\rightarrow t} = \\sum_ {n = 1} ^ {N} \\left(\\mathbf {f} _ {n} \\boldsymbol {\\alpha} _ {n} \\prod_ {m = 1} ^ {n - 1} (1 - \\boldsymbol {\\alpha} _ {m})\\right), \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.383, + 0.892, + 0.49 + ], + "angle": 0, + "content": "where \\(\\mathbf{f}_n\\in \\mathbb{R}^{H\\times W\\times 2}\\) is the optical flow maps on the \\(n\\) -th plane of image \\(\\mathbf{I}_s\\). The pipeline implemented thus far models the optical flows resulting from camera motion without considering the potential presence of independently dynamic objects. However, real-world scenes are highly likely to contain such objects. Not incorporating their motions can lead to domain gaps by unrealistic optical flows." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.507, + 0.892, + 0.583 + ], + "angle": 0, + "content": "Independent Object Motions. To model more realistic motions, we propose applying separate virtual motions to objects and static backgrounds extracted from the scene. Therefore, we utilize an instance segmentation network \\(\\Omega\\) [7] for extracting the main object in the source image \\(\\mathbf{I}_s\\) as:" + }, + { + "type": "equation", + "bbox": [ + 0.615, + 0.597, + 0.891, + 0.615 + ], + "angle": 0, + "content": "\\[\n\\mathbf {M} _ {s} = \\Omega (\\mathbf {I} _ {s}) \\in \\mathbb {R} ^ {H \\times W}, \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.624, + 0.892, + 0.778 + ], + "angle": 0, + "content": "where \\(\\mathbf{M}_s\\) is a binary mask to indicate the region of the object. To model the motions of the object \\(\\mathbf{M}_s\\) in the scene, we construct separate viewpoints, including camera motion \\(\\pmb{\\mu}_t^{sce}\\) and object motion \\(\\pmb{\\mu}_t^{obj}\\). We then obtain the rendered scene novel view \\(\\mathbf{I}_t^{sce}\\) and object novel view \\(\\mathbf{I}_t^{obj}\\) as in Equation (3). The separate optical flows, \\(\\mathbf{F}_{s\\rightarrow t}^{sce}\\) and \\(\\mathbf{F}_{s\\rightarrow t}^{obj}\\) can also be obtained as in Equation (5). The optical flows in \\(\\mathbf{F}_{s\\rightarrow t}\\) are mixed by the values in \\(\\mathbf{F}_{s\\rightarrow t}^{sce}\\) and \\(\\mathbf{F}_{s\\rightarrow t}^{obj}\\) in terms of mask \\(\\mathbf{M}_s\\) to get the final optical flow maps containing camera motion and dynamic objects for training." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.779, + 0.892, + 0.902 + ], + "angle": 0, + "content": "We can then use the bilinear interpolation to get the new object masks \\(\\mathbf{M}_t\\) and \\(\\mathbf{M}_t^{obj}\\) under the new viewpoints \\(\\pmb{\\mu}_t\\) and \\(\\pmb{\\mu}_t^{obj}\\) via bilinear sampling from \\(\\mathbf{M}_s\\). Pixels in the new merged image are also selected according to the content masks \\(1 - \\mathbf{M}_t\\) and \\(\\mathbf{M}_t^{obj}\\) from \\(\\mathbf{I}_t^{sce}\\) and \\(\\mathbf{I}_t^{obj}\\). Then, a simple inpainting strategy [46] is used to fill the empty area in the new image with an inpainting mask calculated by \\(\\mathbf{M}_{fill} = \\mathbf{M}_t\\odot (1 - \\mathbf{M}_t^{obj})\\)." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13860" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.168 + ], + "angle": 0, + "content": "Depth-Aware Inpainting Although merged images give a realistic visual effect, depth changes caused by camera motion and object motion can also cause unnatural occlusions. To solve this problem, we use volume rendering to obtain the depth \\(\\mathbf{D}_t^{sce}\\) of the scene novel view:" + }, + { + "type": "equation", + "bbox": [ + 0.15, + 0.177, + 0.47, + 0.22 + ], + "angle": 0, + "content": "\\[\n\\mathbf {D} _ {t} = \\sum_ {n = 1} ^ {N} \\left(\\mathbf {d} _ {n} ^ {\\prime} \\boldsymbol {\\alpha} _ {n} ^ {\\prime} \\prod_ {m = 1} ^ {n - 1} \\left(1 - \\boldsymbol {\\alpha} _ {m} ^ {\\prime}\\right)\\right), \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.229, + 0.47, + 0.276 + ], + "angle": 0, + "content": "and the depth of the object novel view \\(\\mathbf{D}_t^{obj}\\) can be obtained in the same way. We then utilize both depths to compute the occupation mask between the novel views:" + }, + { + "type": "equation", + "bbox": [ + 0.13, + 0.284, + 0.469, + 0.303 + ], + "angle": 0, + "content": "\\[\n\\mathbf {M} _ {o c c} = \\left(1 - \\mathbf {M} _ {t}\\right) \\odot \\mathbf {M} _ {t} ^ {o b j} \\odot \\left(\\mathbf {D} _ {t} < \\mathbf {D} _ {t} ^ {o b j}\\right), \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.312, + 0.469, + 0.357 + ], + "angle": 0, + "content": "which indicates the background areas in front of the object. Therefore, we are able to restore the coincidence area between the object and the background in the new image \\(\\mathbf{I}_t\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.358, + 0.47, + 0.538 + ], + "angle": 0, + "content": "Figure 3 provides a detailed illustration of the incremental effects of MPI-Flow with and without independent object motion and depth-aware inpainting. Novel view images and optical flows from single-view images can be generated with MPI-Flow and only camera motion, as shown in Figures 3(a) and 3(b). However, camera motion alone does not match the complex optical flows in real-world scenes. To address this issue, we introduce an independent object motion module, as shown in Figure 3(c), to ensure motion realism. To further enhance motion realism and address occlusion caused by object motion, we apply the depth-aware inpainting module, as shown in Figure 3(d)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.551, + 0.21, + 0.568 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.576, + 0.18, + 0.59 + ], + "angle": 0, + "content": "4.1. Datasets" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.599, + 0.469, + 0.704 + ], + "angle": 0, + "content": "FlyingChairs [9] and FlyingThings3D [18] are both popular synthetic datasets that train optical flow models. As a standard practice, we use \"Ch\" and \"Th\" respectively to represent the two datasets, and \"Ch→Th\" means training first on \"Ch\" and fine-tuning on \"Th\". By default, we use the RAFT pre-trained on \"Ch→Th\" to be fine-tuned on the generated datasets and evaluated on labeled datasets." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.705, + 0.469, + 0.78 + ], + "angle": 0, + "content": "COCO [27] is a collection of single still images and ground truth with labels for object detection or panoptic segmentation tasks. We sample 20k single-view still images from the train2017 split following Depthstillation [1] to generate virtual images and optical flow maps." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.469, + 0.854 + ], + "angle": 0, + "content": "DAVIS [37] provides high-resolution videos and it is widely used for video object segmentation. We use all the 10581 images of the unsupervised 2019 challenge to generate datasets by MPI-Flow and other state-of-the-art optical flow dataset generation methods." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.469, + 0.901 + ], + "angle": 0, + "content": "KITTI2012 [11] and KITTI2015 [34] are well-known benchmarks for optical flow estimation. There are multi-view extensions (4,000 for training and 3,989 for testing)" + }, + { + "type": "image", + "bbox": [ + 0.513, + 0.089, + 0.883, + 0.178 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.643, + 0.183, + 0.751, + 0.196 + ], + "angle": 0, + "content": "(a) Source Image" + }, + { + "type": "image", + "bbox": [ + 0.512, + 0.197, + 0.882, + 0.242 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.631, + 0.248, + 0.763, + 0.26 + ], + "angle": 0, + "content": "(b) + Camera Motion" + }, + { + "type": "image", + "bbox": [ + 0.513, + 0.261, + 0.882, + 0.306 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.597, + 0.312, + 0.797, + 0.325 + ], + "angle": 0, + "content": "(c) + Independent Object Motion" + }, + { + "type": "image", + "bbox": [ + 0.512, + 0.326, + 0.882, + 0.37 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.606, + 0.376, + 0.788, + 0.39 + ], + "angle": 0, + "content": "(d) + Depth-Aware Inpainting" + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.402, + 0.892, + 0.432 + ], + "angle": 0, + "content": "Figure 3: Visualization of incrementally adding different modules to improve the realism of the generated data." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.46, + 0.892, + 0.55 + ], + "angle": 0, + "content": "datasets with no ground truth. We use the multi-view extension images (training and testing) of KITTI 2015 to generate datasets, separately. By default, we evaluate the trained models on KITTI 12 training set and KITTI 15 training set in the tables following [1] and [12], abbreviated as \"KITTI 15\" and \"KITTI 12\" in the following tables." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.551, + 0.892, + 0.626 + ], + "angle": 0, + "content": "Sintel [5] is derived from the open-source 3D animated short film Sintel. The dataset has 23 different scenes. The stereo images are RGB, while the disparity is grayscale. Although not a real-world dataset, we use it to verify the model's generalization across domains." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.636, + 0.716, + 0.651 + ], + "angle": 0, + "content": "4.2. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.66, + 0.892, + 0.72 + ], + "angle": 0, + "content": "Firstly, we provide a description of the learning-based optical flow estimation models that were utilized in our experiments. Subsequently, we outline the experimental parameters and setup along with the evaluation formulation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.893, + 0.901 + ], + "angle": 0, + "content": "Optical Flow networks. To evaluate how effective our generated data are at training optical flow models, we select RAFT [45], which represents state-of-the-art architecture for supervised optical flow and has excellent generalization capability. By default, we train RAFT on generated data for 200K steps with a learning rate of \\(1 \\times 10^{-4}\\) and weight decay of \\(1 \\times 10^{-5}\\), batch size of 6, and \\(288 \\times 960\\) image crops. This configuration is the default setting of RAFT fitting on KITTI with two GPUs but four times the number of training steps, following [12]. For the rest of the setup, we use the official implementation of RAFT without any modifications. All evaluations are performed on a single NVIDIA" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "13861" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.141, + 0.089, + 0.833, + 0.289 + ], + "angle": 0, + "content": "
Image SourceMethodSintel.CSintel.FKITTI 12KITTI 15
EPE ↓>3 ↓EPE ↓>3 ↓EPE ↓F1 ↓EPE ↓F1 ↓
COCODepthstillation [1]1.875.313.219.251.746.813.4513.08
RealFlow [12]N/AN/AN/AN/AN/AN/AN/AN/A
MPI-Flow (ours)1.874.593.168.291.364.913.4410.66
DAVISDepthstillation [1]2.707.523.8112.061.816.893.7913.22
RealFlow [12]1.734.813.478.711.596.083.5512.52
MPI-Flow (ours)1.794.773.068.561.415.363.3210.47
KITTI 15 TestDepthstillation [1]4.029.084.9613.231.775.973.9913.34
RealFlow [12]3.737.365.5311.311.275.162.438.86
MPI-Flow (ours)2.255.253.658.891.244.512.167.30
KITTI 15 TrainDepthstillation [1]2.847.184.3111.241.675.71{2.99}{9.94}
RealFlow [12]4.067.684.7811.441.255.02{2.17}{8.64}
MPI-Flow (ours)2.415.393.829.111.264.66{1.88}{7.16}
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.299, + 0.895, + 0.377 + ], + "angle": 0, + "content": "Table 1: The cross-dataset validation results and comparisons with other dataset generation methods from real images or videos are presented in this study. The \"Image Source\" column indicates the dataset used for optical flow training data generation. The evaluation results of RAFT trained on different datasets using different methods are reported. In cases where RealFlow fails to work on single-view images from COCO, the study indicates \"N/A\". The curly braces \"\\{\\}\" represent the use of the unlabeled evaluation set, which is the KITTI 15 training set in this table." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.401, + 0.262, + 0.416 + ], + "angle": 0, + "content": "GeForce RTX 3090 GPU1." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.417, + 0.471, + 0.597 + ], + "angle": 0, + "content": "Virtual Camera Motion. To generate the novel view images from COCO and DAVIS, we adopt the same settings in [1] to build the virtual camera. For KITTI, we empirically build the camera motion with three scalars where \\( t_x, t_y \\) are in \\([-0.2, 0.2]\\) and \\( t_z \\) are in \\([0.1, 0.35]\\). We build the camera rotation with three Euler angles \\( a_x, a_y, a_z \\) in \\([- \\frac{\\pi}{90}, \\frac{\\pi}{90}]\\). We use single camera motion for each image from COCO but multiple camera motions (\\(\\times 4\\) by default) from DAVIS and KITTI as in [12], due to the small number of images and the homogeneity of the scene in video data. We show how the number of camera motions impacts the optical flow network performance in the discussion." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.598, + 0.47, + 0.675 + ], + "angle": 0, + "content": "Evaluation Metrics. We report evaluation results on the average End-Point Error (EPE) and two error rates, respectively the percentage of pixels with an absolute error greater than \\(3 (> 3)\\) or both absolute and relative errors greater than 3 and \\(5\\%\\) respectively (Fl) on all pixels." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.683, + 0.442, + 0.699 + ], + "angle": 0, + "content": "4.3. Comparison with State-of-the-art Methods" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.706, + 0.47, + 0.767 + ], + "angle": 0, + "content": "In this section, we evaluate the effectiveness of the MPI-Flow generation pipeline on public benchmarks. We will highlight the best results in **bold** and **underline** the second-best if necessary among methods trained in fair conditions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.767, + 0.47, + 0.843 + ], + "angle": 0, + "content": "Comparison with Dataset Generation Methods. As a method for generating datasets from real-world images, we compare MPI-Flow with Depthstillation [1] and RealFlow [12], which are representative works in real-world dataset generation. In order to evaluate the effectiveness" + }, + { + "type": "table", + "bbox": [ + 0.541, + 0.399, + 0.855, + 0.501 + ], + "angle": 0, + "content": "
DatasetKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
Ch→Th [18]2.088.865.0017.44
dDAVIS [1]1.816.893.7913.22
MF-DAVIS1.616.413.7712.40
dCOCO [1]1.806.663.8012.44
MF-COCO1.596.223.6811.95
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.51, + 0.892, + 0.557 + ], + "angle": 0, + "content": "Table 2: Results on RAFT trained from scratch under the same setting. \"dX\" are from Depthstillation [1] while \"MF-X\" are from our proposed MPI-Flow" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.583, + 0.892, + 0.854 + ], + "angle": 0, + "content": "of MPI-Flow, we follow the procedures of Depthstillation and RealFlow to construct training sets from four different datasets, including COCO, DAVIS, KITTI 15 multi-view train set, and KITTI 15 multi-view test set. To ensure fair comparisons, we conduct experiments with a similar number of training sets as our competitors. Specifically, for DAVIS and KITTI, we generate four motions for each image to match RealFlow, which trains RAFT for four EM iterations with four times the amount of data. For COCO, we follow the exact same setup as Depthstillation. Since Depthstillation does not provide details for KITTI 15 train, we use its default settings to obtain the results. Trained models are evaluated on the training sets of Sintel, KITTI 12, and KITTI 15. We report the evaluation results of models with the best performance in the paper for Depthstillation and RealFlow. Furthermore, we conduct cross-dataset experiments where RAFT is trained with one generated dataset and evaluated with another." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "As shown in Table 1, even with the same amount of data, our approach gains significant improvements and generalization over multiple datasets. When trained and tested with" + }, + { + "type": "page_footnote", + "bbox": [ + 0.077, + 0.85, + 0.47, + 0.901 + ], + "angle": 0, + "content": "\\(^{1}\\)RAFT with the same parameters loaded on different GPUs yield slightly different evaluation results. Therefore, to ensure fair comparison, we download the official model weights with the best performance provided by the compared methods and evaluate them on the same GPU." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13862" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.088, + 0.278, + 0.137 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.142, + 0.277, + 0.19 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.125, + 0.196, + 0.232, + 0.21 + ], + "angle": 0, + "content": "(a) Source Image" + }, + { + "type": "image", + "bbox": [ + 0.288, + 0.088, + 0.486, + 0.137 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.288, + 0.142, + 0.485, + 0.19 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.33, + 0.196, + 0.443, + 0.21 + ], + "angle": 0, + "content": "(b) Depthstillation" + }, + { + "type": "image", + "bbox": [ + 0.497, + 0.088, + 0.693, + 0.137 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.497, + 0.142, + 0.692, + 0.19 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.554, + 0.196, + 0.635, + 0.209 + ], + "angle": 0, + "content": "(c) RealFlow" + }, + { + "type": "image", + "bbox": [ + 0.696, + 0.088, + 0.892, + 0.137 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.695, + 0.142, + 0.892, + 0.19 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.73, + 0.196, + 0.855, + 0.21 + ], + "angle": 0, + "content": "(d) MPI-Flow (ours)" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.222, + 0.894, + 0.268 + ], + "angle": 0, + "content": "Figure 4: Qualitative results of generated images and optical flows from the KITTI 2015 training set. (a) contains the input source images. (b), (c), and (d) contain generated images of RealFlow [12], Depthstillation [1], and our proposed MPI-Flow. MPI-Flow eliminates the artifact in the new image and guarantees image realism. (Best viewed with zoom-in)" + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.292, + 0.466, + 0.384 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.174, + 0.39, + 0.374, + 0.403 + ], + "angle": 0, + "content": "(a) Source Image from KITTI 15" + }, + { + "type": "image", + "bbox": [ + 0.084, + 0.405, + 0.21, + 0.497 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.09, + 0.503, + 0.203, + 0.516 + ], + "angle": 0, + "content": "(b) Depthstillation" + }, + { + "type": "image", + "bbox": [ + 0.212, + 0.405, + 0.337, + 0.496 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.234, + 0.503, + 0.315, + 0.516 + ], + "angle": 0, + "content": "(c) RealFlow" + }, + { + "type": "image", + "bbox": [ + 0.339, + 0.405, + 0.465, + 0.497 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.339, + 0.503, + 0.464, + 0.516 + ], + "angle": 0, + "content": "(d) MPI-Flow (ours)" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.529, + 0.47, + 0.59 + ], + "angle": 0, + "content": "Figure 5: Visualization of generated images with Depthstillation, RealFlow, and our proposed MPI-Flow from KITTI. Note that RealFlow generates such data using two frames with estimated optical flow." + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.608, + 0.26, + 0.702 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.114, + 0.708, + 0.226, + 0.721 + ], + "angle": 0, + "content": "(a) Depthstillation" + }, + { + "type": "image", + "bbox": [ + 0.289, + 0.608, + 0.468, + 0.702 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.315, + 0.708, + 0.441, + 0.721 + ], + "angle": 0, + "content": "(b) MPI-Flow (ours)" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.734, + 0.47, + 0.765 + ], + "angle": 0, + "content": "Figure 6: Visualization of generated images with Depthstillation and our proposed MPI-Flow using a single view." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.47, + 0.901 + ], + "angle": 0, + "content": "the same KITTI 15 Train image source, our EPE outperforms the second-best by a remarkable 0.29. When trained and tested with different image sources, our MPI-Flow demonstrates clear improvements over the competitors on almost all the evaluation settings. Notably, MPI-Flow achieves much better performance, even though RealFlow requires two consecutive frames to generate datasets, while" + }, + { + "type": "table", + "bbox": [ + 0.506, + 0.292, + 0.888, + 0.462 + ], + "angle": 0, + "content": "
MethodKITTI 12KITTI 15
EPE ↓Fl ↓EPE ↓Fl ↓
SemiFlowGAN [25]--{16.02}{38.77}
FlowSupervisor [20]--{3.35}{11.12}
DistractFlow [21]--{3.01}{11.7}
Meta-Learning [36]--{2.81}-
SimFlow [19]--{5.19}-
ARFlow [28]1.44-{2.85}-
UFlow [22]1.68-2.719.05
UpFlow [33]1.27-2.45-
SMURF [42]--{2.00}{6.42}
MPI-Flow1.184.46{1.80}{6.63}
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.473, + 0.891, + 0.503 + ], + "angle": 0, + "content": "Table 3: Comparison with semi-supervised and unsupervised methods. \\( \\cdot - \\) ’ indicates no results reported." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.535, + 0.75, + 0.55 + ], + "angle": 0, + "content": "MPI-Flow needs only one still image." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.552, + 0.892, + 0.779 + ], + "angle": 0, + "content": "It is worth comparing MPI-Flow with Depthstillation under the same settings to evaluate their performance. For this comparison, we use the exact same settings as Depthstillation. Specifically, we generate MPI-Flow datasets with 1) no object motion, 2) the same camera parameters, 3) one camera motion per image, and 4) without pre-training on \\(\\mathrm{Ch}\\rightarrow \\mathrm{Th}\\). The datasets generated are named MF-DAVIS and MF-COCO, while dCOCO and dDAVIS are generated from Depthstillation. The models are trained from scratch with the respective datasets. RealFlow is not included in this table as it requires a pre-trained optical flow model to generate datasets. The evaluation results are shown in Table 2. Our method outperforms Depthstillation with significant improvements on both COCO and DAVIS, demonstrating the importance of image realism." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Comparison with Unsupervised Methods. Another way to utilize real-world data is through unsupervised learning, which learns optical flow pixels directly without the need for optical flow labels. In order to further demonstrate the effectiveness of MPI-Flow, we compare our method with the existing literature on unsupervised methods. The results of this comparison can be seen in Table 3. All methods are evaluated under the condition that only images from" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "13863" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.14, + 0.089, + 0.832, + 0.176 + ], + "angle": 0, + "content": "
Dynamic ObjectsDepth-Aware InpaintingMultiple ObjectsSintel.CSintel.FKITTI 12KITTI 15
EPE ↓>3 ↓EPE ↓>3 ↓EPE ↓Fl ↓EPE ↓Fl ↓
XXX2.586.104.049.671.204.34{2.46}{8.38}
✓XX2.415.393.829.111.264.66{1.88}{7.16}
✓✓X2.375.443.719.051.254.58{1.91}{7.06}
✓✓✓2.205.353.679.031.234.46{1.92}{7.05}
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.187, + 0.895, + 0.218 + ], + "angle": 0, + "content": "Table 4: Ablation experiments. Settings used are marked with a checkmark. Here we only perform four camera motions per image for these experiments due to the limitation of computational resources." + }, + { + "type": "table", + "bbox": [ + 0.095, + 0.241, + 0.455, + 0.384 + ], + "angle": 0, + "content": "
MethodKITTI 15KITTI 15 test
EPE ↓Fl ↓Fl ↓
PWC-Net [44]{2.16}{9.80}9.60
LiteFlowNet [16]{1.62}{5.58}9.38
IRR-PWC [17]{1.63}{5.32}7.65
RAFT [45]{0.63}{1.50}5.10
Depthstillation [12]---
AutoFlow [43]--4.78
RealFlow [12]{0.58}{1.35}4.63
MPI-Flow{0.58}{1.30}4.58
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.395, + 0.471, + 0.424 + ], + "angle": 0, + "content": "Table 5: Comparison with supervised methods fine-tuned or trained on KITTI 15 train set." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.454, + 0.47, + 0.59 + ], + "angle": 0, + "content": "the evaluation set could be used, without access to ground truth labels. For evaluation, we train the RAFT on our generated dataset with images from the KITTI 15 training set. Our MPI-Flow outperform all unsupervised methods in terms of EPE on both the KITTI 12 training set and KITTI 15 training set, with no need for any unsupervised constraints. However, our method performs better on EPE but has slightly lower F1 than SMURF, mainly because SMURF employs multiple frames for training." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.591, + 0.47, + 0.698 + ], + "angle": 0, + "content": "Comparison with Supervised Methods. To further prove the effectiveness of MPI-Flow, we use KITTI 15 train set to fine-tune RAFT pre-trained by our generated dataset with images from KITTI 15 test set. The evaluation results on KITTI 15 train and KITTI 15 test are shown in Table 5. We achieve state-of-art performance on KITTI 2015 test benchmark compared to supervised methods on training RAFT." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.698, + 0.47, + 0.82 + ], + "angle": 0, + "content": "Qualitative Results. Figure 4 show the generated images from the methods utilizing real-world images, as presented in Table 1. In this comparison, we use images from the KITTI 15 dataset as source image input. The images generated by RealFlow [12] and Depthstillation [1] with artifacts degrade the image realism. In contrast, MPI-Flow generates more realistic images than the other two methods. More results are shown in Figures 5 and 6." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.831, + 0.195, + 0.847 + ], + "angle": 0, + "content": "4.4. Discussion" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.469, + 0.901 + ], + "angle": 0, + "content": "To verify the effectiveness of the proposed MPI-Flow, we discuss the performance of models trained with generated datasets with different settings. We show more discus" + }, + { + "type": "table", + "bbox": [ + 0.553, + 0.241, + 0.842, + 0.342 + ], + "angle": 0, + "content": "
Motions \nPer ImageKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
11.294.582.027.35
41.234.461.927.05
101.214.491.827.02
201.204.411.796.86
401.184.461.806.63
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.353, + 0.892, + 0.384 + ], + "angle": 0, + "content": "Table 6: Effect of amount of virtual camera motions (training pairs) per source image." + }, + { + "type": "table", + "bbox": [ + 0.553, + 0.402, + 0.842, + 0.476 + ], + "angle": 0, + "content": "
Objects \nPer ImageKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
11.254.581.917.06
21.264.762.027.19
41.234.461.927.05
" + }, + { + "type": "table_caption", + "bbox": [ + 0.509, + 0.487, + 0.882, + 0.502 + ], + "angle": 0, + "content": "Table 7: Effect of amount of dynamic objects per image." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.534, + 0.88, + 0.549 + ], + "angle": 0, + "content": "sion and evaluation results in the supplementary material." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.551, + 0.892, + 0.883 + ], + "angle": 0, + "content": "Object Motion and Depth-Aware Inpainting. We conduct a series of ablation studies to analyze the impact of different choices in our proposed MPI-Flow for new image synthesis, including object motion, depth-aware inpainting, and multiple objects. \"Multiple objects\" indicates multiple moving objects in each image. To measure the impact of these factors, we generate new images from the KITTI 15 training set to train RAFT and evaluate them on the KITTI 12 training set and KITTI 15 training set. Because there are multiple combinations of these factors, we test by incrementally adding components of our approach, as shown in Table 4. In the first row, we show the performance achieved by generating new images without dynamic objects, thus assuming that optical flow comes from camera motion only. Then we incrementally add single-object motion, depth-aware inpainting, and multi-object motion to model a more realistic scenario. There are considerable improvements in almost all datasets on various metrics, except for the KITTI 12 training set, possibly due to the infrequent dynamic object motion in this dataset. The EPE on KITTI 15 remains relatively stable within the normal margin after adding the depth-aware inpainting module and the multi-object trick." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.886, + 0.892, + 0.9 + ], + "angle": 0, + "content": "Camera Motion Parameters. We also conduct a series of" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13864" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.115, + 0.089, + 0.434, + 0.177 + ], + "angle": 0, + "content": "
tzKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
0.1 ~ 0.451.254.60{1.79}{6.68}
0.1 ~ 0.351.184.46{1.80}{6.63}
0.1 ~ 0.251.194.50{1.86}{6.71}
0.0 ~ 0.351.124.32{1.94}{6.92}
" + }, + { + "type": "table_caption", + "bbox": [ + 0.14, + 0.187, + 0.406, + 0.203 + ], + "angle": 0, + "content": "Table 8: Effect of motion parameters \\( {t}_{z} \\) ." + }, + { + "type": "table", + "bbox": [ + 0.113, + 0.218, + 0.436, + 0.294 + ], + "angle": 0, + "content": "
txandtyKITTI 12KITTI 15
EPE ↓Fl ↓EPE ↓Fl ↓
-0.3 ~ 0.31.224.42{1.92}{6.83}
-0.2 ~ 0.21.184.46{1.80}{6.63}
-0.1 ~ 0.11.324.99{1.98}{7.02}
" + }, + { + "type": "table_caption", + "bbox": [ + 0.116, + 0.303, + 0.429, + 0.319 + ], + "angle": 0, + "content": "Table 9: Effect of motion parameters \\( {t}_{x} \\) and \\( {t}_{y} \\) ." + }, + { + "type": "table", + "bbox": [ + 0.114, + 0.334, + 0.435, + 0.436 + ], + "angle": 0, + "content": "
DatasetKITTI 12KITTI 15
EPE ↓Fl ↓EPE ↓Fl ↓
Ch→Th [18]4.1421.3810.3533.67
dDAVIS [1]2.8111.296.8821.87
MF-DAVIS2.7011.256.9220.97
dCOCO [1]3.1613.308.4926.06
MF-COCO3.0211.208.2223.40
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.447, + 0.47, + 0.477 + ], + "angle": 0, + "content": "Table 10: Results on PWC-Net trained on generated datasets from scratch under the same setting." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.506, + 0.468, + 0.687 + ], + "angle": 0, + "content": "ablation studies to analyze the impact of different parameters on camera motions. We first show the effect of \\( t_z \\), which indicates the range of moving forward and backward distances, as shown in Table 4. We set the minimum \\( t_z \\) to 0.1 by default, considering that most cameras on vehicles only move forward in the KITTI dataset. We also show the effect of \\( t_x \\) and \\( t_y \\), representing the distance from left to right and from up to down, respectively. Because there are multiple combinations of parameters, we only test a specific parameter of our method in isolation. Settings used by default are underlined. The results show that a more reasonable range of camera motion leads to better performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.688, + 0.468, + 0.794 + ], + "angle": 0, + "content": "Model Architectures The default model used in our paper is RFAT [45]. Table 10 shows that our proposed MPI-Flow also works for PWC-Net [44] compared with depthstillation [1] in a fair setting. We generate data from COCO and DAVIS and train PWC-Net, in which the results are still better than PWC-Net trained on \\(\\mathrm{Ch} \\rightarrow \\mathrm{Th}\\) or datasets generated from depthstillation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Amount of Virtual Motions. We can generate multiple camera motions with multiple dynamic objects for any given single image and thus a variety of paired images and ground-truth optical flow maps. Thus we can increase the number of camera motions to generate more data. Table 6 shows the impact of different amounts of camera motions on model performance. Interestingly, MPI-Flow with 4 mo" + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.089, + 0.89, + 0.163 + ], + "angle": 0, + "content": "
DatasetQuantityKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
Ch→Th [18]47K2.088.865.0017.44
MF-COCO20K1.596.223.6811.95
MF-COCO120K1.515.943.4111.16
" + }, + { + "type": "table_caption", + "bbox": [ + 0.545, + 0.173, + 0.844, + 0.188 + ], + "angle": 0, + "content": "Table 11: Effect of amount of source images." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.218, + 0.892, + 0.413 + ], + "angle": 0, + "content": "tions per image already allows for strong generalization to real domains, outperforming the results achieved using synthetic datasets shown in the previous evaluation results. Increasing the motions per image by factors 10 and 20 both lead to better performance on KITTI 12 and KITTI 15 compared to 4 and 1. Using 40 motions per image gives the best performance on KITTI 15 in terms of Fl. It indicates that a more variegate image content in the generated dataset may be beneficial for generalization to real applications. Table 7 shows the effect of amounts of dynamic objects on model performance. Increasing the number of dynamic objects improves the performance of the model on KITTI 12 but slightly decreases it on KITTI 15 in terms of EPE." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.415, + 0.892, + 0.521 + ], + "angle": 0, + "content": "Quantity of Source Images The number of source images affects the scene diversity of the generated dataset. Empirically, more source images will be more conducive to model learning, as verified in Table 11. We verify the effect of the number of source images on the MF-COCO. The model performance is significantly improved by increasing the number of source images." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.538, + 0.618, + 0.554 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.565, + 0.892, + 0.805 + ], + "angle": 0, + "content": "In this paper, we present a new framework for generating optical flow datasets, which addresses two main challenges: image realism and motion realism. Firstly, we propose an MPI-based image rendering pipeline that generates realistic images with corresponding optical flows from novel viewpoints. This pipeline utilizes volume rendering to address image artifacts and holes, leading to more realistic images. Secondly, we introduce an independent object motion module that separates dynamic objects from the static scene. By decoupling object motion, we further improve motion realism. Additionally, we design a depth-aware inpainting module that handles unnatural occlusions caused by object motion in the generated images. Through these novel designs, our approach achieves superior performance on real-world datasets compared to both unsupervised and supervised methods for training learning-based models." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.892, + 0.9 + ], + "angle": 0, + "content": "Acknowledgments This work was supported by the National Natural Science Foundation of China (12202048, 62171038, and 62171042), the R&D Program of Beijing Municipal Education Commission (KZ202211417048), and the Fundamental Research Funds for the Central Universities." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "13865" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.105 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.115, + 0.47, + 0.171 + ], + "angle": 0, + "content": "[1] Filippo Aleotti, Matteo Poggi, and Stefano Mattoccia. Learning optical flow from still images. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 15201-15211, 2021. 1, 2, 3, 5, 6, 7, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.172, + 0.472, + 0.227 + ], + "angle": 0, + "content": "[2] Simon Baker, Daniel Scharstein, JP Lewis, Stefan Roth, Michael J Black, and Richard Szeliski. A database and evaluation methodology for optical flow. International Journal of Computer Vision (IJCV), 92(1):1-31, 2011. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.228, + 0.47, + 0.282 + ], + "angle": 0, + "content": "[3] Thomas Brox, Christoph Bregler, and Jitendra Malik. Large displacement optical flow. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 41-48, 2009. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.284, + 0.47, + 0.34 + ], + "angle": 0, + "content": "[4] D. J. Butler, J. Wulff, G. B. Stanley, and M. J. Black. A naturalistic open source movie for optical flow evaluation. In the European Conference on Computer Vision (ECCV), pages 611-625, 2012. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.341, + 0.47, + 0.396 + ], + "angle": 0, + "content": "[5] Daniel J Butler, Jonas Wulff, Garrett B Stanley, and Michael J Black. A naturalistic open source movie for optical flow evaluation. In the European Conference on Computer Vision (ECCV), pages 611-625, 2012. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.398, + 0.47, + 0.466 + ], + "angle": 0, + "content": "[6] Gustavo Sutter P. Carvalho, Diogo Carbonera Luvizon, Antonio Joia Neto, Andre G. C. Pacheco, and Otavio Augusto Bizetto Penatti. Learning multiplane images from single views with self-supervision. In British Machine Vision Conference (BMVC), 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.467, + 0.47, + 0.536 + ], + "angle": 0, + "content": "[7] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1290–1299, 2022. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.537, + 0.47, + 0.591 + ], + "angle": 0, + "content": "[8] Jiyu Cheng, Yuxiang Sun, and Max Q-H Meng. Improving monocular visual slam in dynamic environments: an optical-flow-based approach. Advanced Robotics, 33(12):576-589, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.593, + 0.47, + 0.675 + ], + "angle": 0, + "content": "[9] Alexey Dosovitskiy, Philipp Fischer, Eddy Ilg, Philip Hausser, Caner Hazirbas, Vladimir Golkov, Patrick Van Der Smagt, Daniel Cremers, and Thomas Brox. Flownet: Learning optical flow with convolutional networks. In the IEEE International Conference on Computer Vision (ICCV), pages 2758-2766, 2015. 1, 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.677, + 0.469, + 0.732 + ], + "angle": 0, + "content": "[10] Bo Du, Shihan Cai, and Chen Wu. Object tracking in satellite videos based on a multiframe optical flow tracker (j-stars). the IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 12(8):3043-3055, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.733, + 0.469, + 0.789 + ], + "angle": 0, + "content": "[11] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the kitti vision benchmark suite. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3354-3361, 2012. 1, 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.79, + 0.469, + 0.858 + ], + "angle": 0, + "content": "[12] Yunhui Han, Kunming Luo, Ao Luo, Jiangyu Liu, Haoqiang Fan, Guiming Luo, and Shuaicheng Liu. Realflow: Embased realistic optical flow dataset generation from videos. In the European Conference on Computer Vision (ECCV), pages 288-305, 2022. 1, 2, 3, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.86, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[13] Yuxuan Han, Ruicheng Wang, and Jiaolong Yang. Single-view synthesis in the wild with learned adaptive multiplane images. In ACM SIGGRAPH, 2022. 2, 3, 4" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.115, + 0.472, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.188 + ], + "angle": 0, + "content": "[14] Toshihide Hanari, Kuniaki Kawabata, and Keita Nakamura. Image selection method from image sequence to improve computational efficiency of 3d reconstruction: Analysis of inter-image displacement based on optical flow for evaluating 3d reconstruction performance. In the IEEE International Symposium on System Integration (SII), pages 1041-1045, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.19, + 0.892, + 0.232 + ], + "angle": 0, + "content": "[15] Anders Heyden and Marc Pollefeys. Multiple view geometry. Emerging topics in computer vision, 3:45-108, 2005. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.234, + 0.893, + 0.302 + ], + "angle": 0, + "content": "[16] Tak-Wai Hui, Xiaou Tang, and Chen Change Loy. Liteflownet: A lightweight convolutional neural network for optical flow estimation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 8981-8989, 2018. 2, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.304, + 0.893, + 0.36 + ], + "angle": 0, + "content": "[17] Junhwa Hur and Stefan Roth. Iterative residual refinement for joint optical flow and occlusion estimation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 5754-5763, 2019. 2, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.362, + 0.893, + 0.432 + ], + "angle": 0, + "content": "[18] Eddy Ig, Nikolaus Mayer, Tonmoy Saikia, Margret Keuper, Alexey Dosovitskiy, and Thomas Brox. Flownet 2.0: Evolution of optical flow estimation with deep networks. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 2462-2470, 2017. 1, 2, 5, 6, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.433, + 0.893, + 0.488 + ], + "angle": 0, + "content": "[19] Woobin Im, Tae-Kyun Kim, and Sung-Eui Yoon. Unsupervised learning of optical flow with deep feature similarity. In the European Conference on Computer Vision (ECCV), pages 172-188, 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.49, + 0.893, + 0.544 + ], + "angle": 0, + "content": "[20] Woobin Im, Sebin Lee, and Sung-Eui Yoon. Semi-supervised learning of optical flow by flow supervisor. In the European Conference on Computer Vision (ECCV), pages 302-318, 2022. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.547, + 0.893, + 0.615 + ], + "angle": 0, + "content": "[21] Jisoo Jeong, Hong Cai, Risheek Garrepalli, and Fatih Porikli. Distractflow: Improving optical flow estimation via realistic distractions and pseudo-labeling. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 13691-13700, 2023. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.617, + 0.893, + 0.673 + ], + "angle": 0, + "content": "[22] Rico Jonschkowski, Austin Stone, Jonathan T Barron, Ariel Gordon, Kurt Konolige, and Anelia Angelova. What matters in unsupervised optical flow. In the European Conference on Computer Vision (ECCV), pages 557-572, 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.675, + 0.893, + 0.758 + ], + "angle": 0, + "content": "[23] Artúr I Károly, Renata Nagyné Elek, Tamás Haidegger, Károly Széll, and Péter Galambos. Optical flow-based segmentation of moving objects for mobile robot navigation using pre-trained deep learning models. In the IEEE International Conference on Systems, Man and Cybernetics (SMC), pages 3080-3086, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.759, + 0.893, + 0.815 + ], + "angle": 0, + "content": "[24] Filippos Kokkinos and Iasonas Kokkinos. Learning monocular 3d reconstruction of articulated categories from motion. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1737-1746, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.817, + 0.893, + 0.871 + ], + "angle": 0, + "content": "[25] Wei-Sheng Lai, Jia-Bin Huang, and Ming-Hsuan Yang. Semi-supervised learning for optical flow with generative adversarial networks. Advances in Neural Information Processing Systems (NIPS), 30, 2017. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.873, + 0.893, + 0.901 + ], + "angle": 0, + "content": "[26] Jiaxin Li, Zijian Feng, Qi She, Henghui Ding, Changhu Wang, and Gim Hee Lee. Mine: Towards continuous depth" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.52, + 0.957 + ], + "angle": 0, + "content": "13866" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.093, + 0.469, + 0.133 + ], + "angle": 0, + "content": "MPI with nerf for novel view synthesis. In the IEEE International Conference on Computer Vision (ICCV), pages 12578-12588, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.469, + 0.205 + ], + "angle": 0, + "content": "[27] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In the European Conference on Computer Vision (ECCV), pages 740-755, 2014. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.207, + 0.469, + 0.29 + ], + "angle": 0, + "content": "[28] Liang Liu, Jiangning Zhang, Ruifei He, Yong Liu, Yabiao Wang, Ying Tai, Donghao Luo, Chengjie Wang, Jilin Li, and Feiyue Huang. Learning by analogy: Reliable supervision from transformations for unsupervised optical flow estimation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 6489-6498, 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.292, + 0.469, + 0.346 + ], + "angle": 0, + "content": "[29] Yubao Liu and Jun Miura. Rdmo-slam: Real-time visual slam for dynamic environments using semantic label prediction with optical flow. IEEE Access, 9:106981-106997, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.349, + 0.469, + 0.403 + ], + "angle": 0, + "content": "[30] Stephen Lombardi, Tomas Simon, Jason Saragih, Gabriel Schwartz, Andreas Lehrmann, and Yaser Sheikh. Neural volumes: Learning dynamic renderable volumes from images. arXiv preprint arXiv:1906.07751, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.406, + 0.469, + 0.46 + ], + "angle": 0, + "content": "[31] Ao Luo, Fan Yang, Xin Li, and Shuaicheng Liu. Learning optical flow with kernel patch attention. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 8906-8915, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.463, + 0.469, + 0.517 + ], + "angle": 0, + "content": "[32] Ao Luo, Fan Yang, Kunming Luo, Xin Li, Haoqiang Fan, and Shuaicheng Liu. Learning optical flow with adaptive graph reasoning. In the AAAI Conference on Artificial Intelligence, volume 36, pages 1890-1898, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.52, + 0.469, + 0.587 + ], + "angle": 0, + "content": "[33] Kunming Luo, Chuan Wang, Shuaicheng Liu, Haoqiang Fan, Jue Wang, and Jian Sun. Upflow: Upsampling pyramid for unsupervised optical flow learning. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1045-1054, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.591, + 0.469, + 0.644 + ], + "angle": 0, + "content": "[34] Moritz Menze and Andreas Geiger. Object scene flow for autonomous vehicles. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3061-3070, 2015. 1, 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.647, + 0.469, + 0.714 + ], + "angle": 0, + "content": "[35] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.718, + 0.469, + 0.773 + ], + "angle": 0, + "content": "[36] Chaerin Min, Taehyun Kim, and Jongwoo Lim. Meta-learning for adaptation of deep optical flow networks. In the IEEE Winter Conference on Applications of Computer Vision (WACV), pages 2145-2154, 2023. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.776, + 0.469, + 0.856 + ], + "angle": 0, + "content": "[37] Federico Perazzi, Jordi Pont-Tuset, Brian McWilliams, Luc Van Gool, Markus Gross, and Alexander Sorkine-Hornung. A benchmark dataset and evaluation methodology for video object segmentation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 724-732, 2016. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.86, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[38] René Ranftl, Katrin Lasinger, David Hafner, Konrad Schindler, and Vladlen Koltun. Towards robust monocular depth estimation: Mixing datasets for zero-shot cross-dataset" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.093, + 0.469, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "transfer. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 44(3):1623-1637, 2020. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.122, + 0.892, + 0.176 + ], + "angle": 0, + "content": "[39] Chris Rockwell, David F Fouhey, and Justin Johnson. Pixelsynth: Generating a 3d-consistent experience from a single image. In the IEEE International Conference on Computer Vision (ICCV), pages 14104-14113, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.178, + 0.892, + 0.232 + ], + "angle": 0, + "content": "[40] Robin Rombach, Patrick Esser, and Björn Ommer. Geometry-free view synthesis: Transformers and no 3d priors. In the IEEE International Conference on Computer Vision (ICCV), pages 14356-14366, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.234, + 0.892, + 0.287 + ], + "angle": 0, + "content": "[41] Nitin J Sanket, Chahat Deep Singh, Cornelia Fermüller, and Yiannis Aloimonos. Prgflow: Unified swap-aware deep global optical flow for aerial robot navigation. *Electronics Letters*, 57(16):614–617, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.289, + 0.892, + 0.357 + ], + "angle": 0, + "content": "[42] Austin Stone, Daniel Maurer, Alper Ayvaci, Anelia Angelova, and Rico Jonschkowski. Smurf: Self-teaching multiframe unsupervised raft with full-image warping. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3887-3896, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.359, + 0.892, + 0.44 + ], + "angle": 0, + "content": "[43] Deqing Sun, Daniel Vlasic, Charles Herrmann, Varun Jampani, Michael Krainin, Huiwen Chang, Ramin Zabih, William T Freeman, and Ce Liu. Autoflow: Learning a better training set for optical flow. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 10093-10102, 2021. 2, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.442, + 0.892, + 0.509 + ], + "angle": 0, + "content": "[44] Deqing Sun, Xiaodong Yang, Ming-Yu Liu, and Jan Kautz. Pwc-net: Cnns for optical flow using pyramid, warping, and cost volume. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 8934-8943, 2018. 1, 2, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.511, + 0.892, + 0.552 + ], + "angle": 0, + "content": "[45] Zachary Teed and Jia Deng. Raft: Recurrent all-pairs field transforms for optical flow. In the European Conference on Computer Vision (ECCV), pages 402-419, 2020. 1, 2, 5, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.554, + 0.892, + 0.593 + ], + "angle": 0, + "content": "[46] Alexandru Telea. An image inpainting technique based on the fast marching method. Journal of graphics tools, 9(1):23-34, 2004. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.596, + 0.892, + 0.649 + ], + "angle": 0, + "content": "[47] Richard Tucker and Noah Snively. Single-view view synthesis with multiplane images. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 551-560, 2020. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.651, + 0.892, + 0.705 + ], + "angle": 0, + "content": "[48] Shubham Tulsiani, Richard Tucker, and Noah Snavely. Layer-structured 3d scene inference via view synthesis. In the European Conference on Computer Vision (ECCV), pages 302–317, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.707, + 0.892, + 0.773 + ], + "angle": 0, + "content": "[49] Philippe Weinzaepfel, Jerome Revaud, Zaid Harchaoui, and Cordelia Schmid. Deepflow: Large displacement optical flow with deep matching. In the IEEE International Conference on Computer Vision (ICCV), pages 1385-1392, 2013. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.776, + 0.892, + 0.817 + ], + "angle": 0, + "content": "[50] Christopher Zach, Thomas Pock, and Horst Bischof. A duality based approach for realtime tv-l 1 optical flow. In Pattern Recognition, pages 214-223, 2007. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.818, + 0.892, + 0.871 + ], + "angle": 0, + "content": "[51] Jimuyang Zhang, Sanping Zhou, Xin Chang, Fangbin Wan, Jinjun Wang, Yang Wu, and Dong Huang. Multiple object tracking by flowing and fusing. arXiv preprint arXiv:2001.11180, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.873, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[52] Tianwei Zhang, Huayan Zhang, Yang Li, Yoshihiko Nakamura, and Lei Zhang. Flowfusion: Dynamic dense rgb-d" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13867" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.134 + ], + "angle": 0, + "content": "slam based on optical flow. In the IEEE International Conference on Robotics and Automation (ICRA), pages 7322-7328, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.47, + 0.189 + ], + "angle": 0, + "content": "[53] Tinghui Zhou, Richard Tucker, John Flynn, Graham Fyffe, and Noah Snavely. Stereo magnification: Learning view synthesis using multiplane images. In ACM SIGGRAPH, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.192, + 0.469, + 0.26 + ], + "angle": 0, + "content": "[54] Yuemei Zhou, Gaochang Wu, Ying Fu, Kun Li, and Yebin Liu. Cross-mpi: Cross-scale stereo for image super-resolution using multiplane images. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 14842-14851, 2021. 2" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.26 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.956 + ], + "angle": 0, + "content": "13868" + } + ] +] \ No newline at end of file diff --git a/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/d01da3cc-92b1-43b1-b6d0-867a68823626_origin.pdf b/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/d01da3cc-92b1-43b1-b6d0-867a68823626_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..834f53237c40ab13ad770417ffad3bef3cbbf6e6 --- /dev/null +++ b/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/d01da3cc-92b1-43b1-b6d0-867a68823626_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:e4bf31ed755168699e653e0006156eeb9c8d2b92190b62b5f7ac0409cdae279d +size 9264349 diff --git a/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/full.md b/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/full.md new file mode 100644 index 0000000000000000000000000000000000000000..04fb44c4c4638cf9e610107a2fbaac9cae68403b --- /dev/null +++ b/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/full.md @@ -0,0 +1,395 @@ +# MPI-Flow: Learning Realistic Optical Flow with Multiplane Images + +Yingping Liang + +Jiaming Liu2 + +1Beijing Institute of Technology + +Debing Zhang + +$^{2}$ Xiaohongshu Inc. + +Ying Fu $^{1*}$ + +# Abstract + +The accuracy of learning-based optical flow estimation models heavily relies on the realism of the training datasets. Current approaches for generating such datasets either employ synthetic data or generate images with limited realism. However, the domain gap of these data with real-world scenes constrains the generalization of the trained model to real-world applications. To address this issue, we investigate generating realistic optical flow datasets from real-world images. Firstly, to generate highly realistic new images, we construct a layered depth representation, known as multiplane images (MPI), from single-view images. This allows us to generate novel view images that are highly realistic. To generate optical flow maps that correspond accurately to the new image, we calculate the optical flows of each plane using the camera matrix and plane depths. We then project these layered optical flows into the output optical flow map with volume rendering. Secondly, to ensure the realism of motion, we present an independent object motion module that can separate the camera and dynamic object motion in MPI. This module addresses the deficiency in MPI-based single-view methods, where optical flow is generated only by camera motion and does not account for any object movement. We additionally devise a depth-aware inpainting module to merge new images with dynamic objects and address unnatural motion occlusions. We show the superior performance of our method through extensive experiments on real-world datasets. Moreover, our approach achieves state-of-the-art performance in both unsupervised and supervised training of learning-based models. The code will be made publicly available at: https://github.com/Sharpiless/MPI-Flow. + +# 1. Introduction + +Optical flow refers to the precise calculation of per-pixel motion between consecutive video frames. Its applications span a wide range of fields, including object tracking [10, 51], robot navigation [23, 41], three-dimensional (3D) + +![](images/8e844a68db9a3d09806e8131d5e8cb1d25c391c6f54206fefc57145afc1cab14.jpg) + +![](images/03169b595941f422c7b2dde1d3c9bef26c81ae30ee51b95a2ffe63985f4001fe.jpg) + +![](images/d17c980ac8900ca411665bf4d481dbfbd5db15c428133f7aaab0ad3d27fc8c2a.jpg) + +![](images/8c0900c23bc1bc953c01c4f74b3041bddccce71d00bd1153b855a0c44ab3f696.jpg) +(a) Depthstill. [1] +(b) RealFlow [12] +(d) Source image and details of generated flows from our method +Figure 1: Visual comparison of images reveals that our method, when compared with those based on real-world images [1, 12], demonstrates superior image realism. Our method also achieves fine optical flows by employing volume rendering in MPI and separate motions of the camera and object with the independent object motion module. + +![](images/7433d0b51b7f26fcdf4cead53a8b2642c8617783130d423ab7dd8ea0b212f879.jpg) +(c) Ours + +reconstruction [24, 14], and visual simultaneous localization and mapping (SLAM) [52, 8, 29]. In recent years, with the rapid development of neural networks, learning-based methods [44, 45] have demonstrated significant advances compared to traditional model-based algorithms [3, 49, 50]. Conventional practices primarily rely on synthetic data, as demonstrated by [9, 18, 4]. Synthetic data contains exact optical flow labels and animated images. However, the domain gap between synthetic and real data hinders its further improvements in real-world applications. + +Recent studies have aimed to extract optical flow from real-world data by employing hand-made special hardware [2, 11, 34]. However, the rigidly controlled and inefficient collection procedure limits their applicability. To address this issue, Depthstillation [1], and RealFlow [12] have been proposed, which project each pixel in the real-world image onto the novel view frame with the help of random motions + +of virtual cameras or estimated flows. Nonetheless, both methods are limited by the lack of image realism, leading to issues such as collisions, holes, and artifacts, as illustrated in Figure 1. These limitations constrain the real-world performance of learning-based optical flow models [44, 45]. + +To achieve higher image realism, we turn our attention to the use of single-view Multiplane Images (MPI) [53, 47, 54, 6, 13]. This line of work demonstrates remarkable single-view image rendering capabilities and effectively reduces collisions, holes, and artifacts commonly found in previous methods [1, 12]. These advancements contribute to higher image realism, prompting a natural question: Can high-realistic MPI methods be adapted to generate high-quality optical flow datasets for training purposes? + +To this end, we propose MPI-Flow, aiming to generate realistic optical flow datasets from real-world images. Specifically, we first review the image synthesis pipeline of MPI and devise an optical flow generation pipeline along with image synthesis. In this step, we build an MPI by warping single-view image features onto each layered plane with the predicted color and density. The color and density then be mapped into a realistic new image via volume rendering. With the layered planes, we extract optical flows with virtual camera motions from the rendered image and the real image. Second, as the MPI can only be applied in static scenes, which yield limited motion realism, we propose an independent object motion module and a depth-aware inpainting module to tackle this issue. The independent object motion module decouples dynamic objects from static scenes and applies different virtual camera matrices to calculate the motion of both dynamic and static parts. The depth-aware inpainting module is introduced to remove the object occlusion in the synthesized new image. + +With MPI-Flow, a large number of single-view images can be used to generate large-scale training datasets with realistic images and motions. This enables learning-based optical flow models better generalization to a wide range of real-world scenes. Extensive experiments on real datasets demonstrate the effectiveness of our approach. In summary, our main contributions are as follows: + +- We are the first to present a novel MPI-based optical flow dataset generation framework, namely MPI-Flow, which can significantly improve the realism of the generated images and motion. +- We present a novel independent object motion module for modeling dynamic objects in MPI, which can model realistic optical flow from camera motion and object motion simultaneously. +- We design a depth-aware inpainting module for realistic image inpainting, which can remove unnatural motion occlusions in generated images. + +# 2. Related Work + +In this section, we review the most relevant studies on optical flow networks, optical flow dataset generation, and novel view image synthesis methods. + +Supervised Optical Flow Network. Early methods train deep neural networks to match patches across images [49]. FlowNet [9] first trains convolutional neural networks on the synthetic datasets with optical flow. Moreover, the follow-up methods [16, 17, 18, 32, 31] with advanced modules and network architectures make a significant improvement in supervised optical flow learning, with RAFT [45] representing state-of-the-art. However, generalization remains a cause for concern due to the domain gap between synthetic datasets and real-world applications. To address this problem, our work focuses on generating realistic optical flow datasets from real-world images. + +Dataset Generation for Optical Flow. The use of fluorescent texture to record motions in real-world scenes is first described in [2] to obtain flow maps. KITTI [11, 34] provides sophisticated training data through complex lidar and camera setups. However, the aforementioned real-world datasets have limited quantities and constrained scenes, making it difficult for models trained using deep supervised learning to generalize to more expansive scenes. Synthesized training pairs, such as those in Flyingchairs [9] and Flyingthings [18], have shown promise for supervised learning. However, moving animated image patches cannot accurately match real-world scenes, leading to domain gaps. AutoFlow [43] introduces a learning-based approach for generating training data by hyper-parameters searching. However, AutoFlow relies on optical flow labels for domain adaptation, which is not practical in most scenarios where ground truth labels are unavailable. + +Two recent works have proposed methods for generating training datasets based on real-world images or videos. The first, called Depthstillation [1], synthesizes paired images by estimating depth and optical flows from a single still image. Optical flows are calculated based on the virtual camera pose and depth. The second method, called RealFlow [12], synthesizes intermediate frames between two frames using estimated optical flows with RAFT. However, both methods use naive image synthesis techniques that fail to meet the demand for realism criteria due to hole-filling and artifacts. In contrast, our method improves on this approach by using a well-designed and modified multiplane image (MPI) technique to obtain realistic images. + +Novel View Synthesis. View synthesis methods aim to generate new images from arbitrary viewpoints by utilizing a given scene. Several classical approaches [48, 30, 53, 35] have been proposed that utilize multiple views of a scene to render novel views with geometric consistency. However, synthesizing novel views from a single image remains challenging due to the limited scene information available. + +![](images/de6823920601c4a5726be68fa470e124ef72f03b4ef82d2c20216b5838b136b9.jpg) +Figure 2: Illustration of our proposed MPI-Flow framework with single-view image $\mathbf{I}_s$ as input. We estimate depths to construct MPI where RGB and density of each plane are predicted by neural networks and the flow of each plane is calculated with camera matrixes. Both the novel views and flow maps are rendered by volume rendering and separated by the independent object motion module with novel view object masks. The new image is merged by depth-aware inpainting. + +Pixelsynth [39] and Geometry-Free View Synthesis [40] address this challenge by optimizing the synthesizing model using multi-view supervision. However, their generalization to in-the-wild scenes is hindered by the lack of large-scale multi-view datasets. Single-view MPI [47] and MINE [26] decompose the scene into multiple layers and utilize an inpainting network to extend each occluded layer. Additionally, AdaMPI [13] addresses complex 3D scene structures through a novel plane adjustment network. These MPI-based methods have demonstrated success in synthesizing realistic images, and thus, we adopt multiplane images as our basic synthesis tool. However, to the best of our knowledge, there are currently no publicly available methods for generating optical flow datasets from MPI. To extract optical flows from MPI, we propose a novel pipeline that differs from previous MPI-based image synthesis methods by utilizing layered depths and virtual camera poses. Additionally, to enhance the realism of the generated optical flow dataset, we introduce an independent object motion module for static and dynamic decoupling, as well as a depth-aware inpainting module to remove unnatural occupations. + +# 3. The Proposed MPI-Flow + +In this section, we first briefly review the basics of our motivation and formulation for novel view image generation. Then we introduce the optical flow generation + +pipeline. Next, we present the details of two crucial components of our approach, including independent object motions and depth-aware inpainting. + +# 3.1. Motivation and Formulation + +Our goal is to generate a realistic novel view image $\mathbf{I}_t\in \mathbb{R}^{H\times W\times 3}$ and the corresponding optical flow maps $\mathbf{F}_{s\rightarrow t}\in \mathbb{R}^{H\times W\times 2}$ from single-view image $\mathbf{I}_s\in \mathbb{R}^{H\times W\times 3}$ . $H$ and $W$ are the height and width of the image, respectively. The two-dimensional array on the optical flow $\mathbf{F}_{s\rightarrow t}$ represents the change of the corresponding pixel from image $\mathbf{I}_s$ to image $\mathbf{I}_t$ . The input image, generated image, and optical flow together form a training pair. + +To generate training pair, previous works [1, 12] wrap pixels from image $\mathbf{I}_s$ to image $\mathbf{I}_t$ with estimated flows. This inevitably leads to holes and artifacts in the image $\mathbf{I}_t$ , which damages the image realism. Recent work [47, 26, 13] on Multiplane Images (MPI) reveals that the layered depth representation of the single-view image can significantly improve the realism of the generated novel view image. + +We aim to tackle the image realism challenges in our methods and meanwhile enhance the optical flow realism and motion realism. Accordingly, we present an MPI-based optical flow dataset generation method, namely MPI-Flow. Figure 2 shows the MPI-Flow framework for training pair generation. To construct MPI, given the input image $\mathbf{I}_s$ , + +an off-the-shelf monocular depth estimation network [38] is used to estimate its depth map. Then we use a neural network to construct $N$ fronto-parallel RGB $\sigma$ planes with color, density, and depth predicted by neural networks in the rays under novel viewpoints. + +To decouple dynamic objects, an instance segmentation network [7] gives the object mask. Then we use bilinear interpolation to obtain the object masks under two viewpoints respectively. Using object masks and constructed MPI, we use volume rendering to render the separate novel view images, optical flow maps, and depths of dynamic objects and the static scene, respectively. The optical flow $\mathbf{F}_{s\rightarrow t}$ can be obtained simply by adding the optical flows of the objects and the scene. However, due to different viewpoints, merging new images results in vacant areas and false occlusion. To this end, we design a depth-aware inpainting module, using rendered depths and object masks to fill the holes and repair false occlusion in the synthesized new image $\mathbf{I}_t$ + +# 3.2. Optical Flow Data Generation + +Novel View Image from MPI. To render realistic image $\mathbf{I}_t$ under a target viewpoint $\pmb{\mu}_t$ , we use pixel warping from the source-view MPI in a differentiable manner. Specifically, we use a neural network $\mathcal{F}$ as in [13] to construct $N$ frontoparallel RGB $\sigma$ planes under source viewpoint $\pmb{\mu}_s$ with color channels $\mathbf{c}_n$ , density channel $\sigma_n$ , and depth $\mathbf{d}_n$ from the input image $\mathbf{I}_s$ and its depth map $\mathbf{D}_s$ as: + +$$ +\left\{\left(\mathbf {c} _ {n}, \boldsymbol {\sigma} _ {n}, \mathbf {d} _ {n}\right) \right\} _ {n = 1} ^ {N} = \mathcal {F} \left(\mathbf {I} _ {s}, \mathbf {D} _ {s}\right), \tag {1} +$$ + +where $N$ is a predefined parameter that represents the number of planes in MPI. Each pixel $(x_{t},y_{t})$ on the novel view image plane can be mapped to pixel $(x_{s},y_{s})$ on $n$ -th source MPI plane via homography function [15]: + +$$ +\left[ x _ {s}, y _ {s}, 1 \right] ^ {T} \sim \mathbf {K} \left(\mathbf {R} - \frac {\mathbf {t n} ^ {T}}{\mathbf {d} _ {n}}\right) \mathbf {K} ^ {- 1} \left[ x _ {t}, y _ {t}, 1 \right] ^ {T}, \tag {2} +$$ + +where $\mathbf{R}$ and $\mathbf{t}$ are the rotation and translation from the source viewpoints $\pmb{\mu}_{s}$ to the target viewpoints $\pmb{\mu}_{t}$ , $\mathbf{K}$ is the camera intrinsic, and $\mathbf{n} = [0,0,1]$ is the normal vector. Thus, the color $\mathbf{c}_n^\prime$ and density $\sigma_{n}^{\prime}$ of each new plane for the novel view $\mathbf{I}_t$ can be obtained via bilinear sampling. We use discrete intersection points between new planes and arbitrary rays passing through the scene and estimate integrals: + +$$ +\mathbf {I} _ {t} = \sum_ {n = 1} ^ {N} \left(\mathbf {c} _ {n} ^ {\prime} \boldsymbol {\alpha} _ {n} ^ {\prime} \prod_ {m = 1} ^ {n - 1} \left(1 - \boldsymbol {\alpha} _ {m} ^ {\prime}\right)\right), \tag {3} +$$ + +where $\alpha_{n}^{\prime} = \exp \left(-\delta_{n}\sigma_{n}^{\prime}\right)$ and $\delta_{n}$ is the distance map between plane $n$ and $n + 1$ and we set the initial depth of MPI planes uniformly spaced in disparity as in [13]. + +Optical Flow from MPI. Although MPI-based methods synthesize realistic images, reliable optical flow maps are + +also needed to train learning-based optical flow estimation models. Therefore, we propose adding an additional optical channel in each plane. To this end, we compute the optical flow on the $n$ -th plane at pixel $[x_s, y_s]$ of source image $\mathbf{I}_s$ by $\mathbf{f}_n = [x_t - x_s, y_t - y_s]$ with a backward-warp process in terms of the inverse equivalent form of Equation (2): + +$$ +\left[ x _ {t}, y _ {t}, 1 \right] ^ {T} \sim \mathbf {K} \left(\mathbf {R} ^ {\dagger} - \frac {\mathbf {t} ^ {\dagger} \mathbf {n} ^ {T}}{\mathbf {d} _ {n}}\right) \mathbf {K} ^ {- 1} \left[ x _ {s}, y _ {s}, 1 \right] ^ {T}, \tag {4} +$$ + +where $x_{s}$ and $y_{s}$ are uniformly sampled from a $H\times W$ grid. $\mathbf{R}^{\dagger}$ and $\mathbf{t}^{\dagger}$ are the inverses of $\mathbf{R}$ and $\mathbf{t}$ , respectively. + +To make sure that the optical flow maps match the novel view image $\mathbf{I}_t$ perfectly, we propose to render $\mathbf{F}_{s\rightarrow t}$ as in Equation (3) in terms of volume rendering: + +$$ +\mathbf {F} _ {s \rightarrow t} = \sum_ {n = 1} ^ {N} \left(\mathbf {f} _ {n} \boldsymbol {\alpha} _ {n} \prod_ {m = 1} ^ {n - 1} (1 - \boldsymbol {\alpha} _ {m})\right), \tag {5} +$$ + +where $\mathbf{f}_n\in \mathbb{R}^{H\times W\times 2}$ is the optical flow maps on the $n$ -th plane of image $\mathbf{I}_s$ . The pipeline implemented thus far models the optical flows resulting from camera motion without considering the potential presence of independently dynamic objects. However, real-world scenes are highly likely to contain such objects. Not incorporating their motions can lead to domain gaps by unrealistic optical flows. + +Independent Object Motions. To model more realistic motions, we propose applying separate virtual motions to objects and static backgrounds extracted from the scene. Therefore, we utilize an instance segmentation network $\Omega$ [7] for extracting the main object in the source image $\mathbf{I}_s$ as: + +$$ +\mathbf {M} _ {s} = \Omega (\mathbf {I} _ {s}) \in \mathbb {R} ^ {H \times W}, \tag {6} +$$ + +where $\mathbf{M}_s$ is a binary mask to indicate the region of the object. To model the motions of the object $\mathbf{M}_s$ in the scene, we construct separate viewpoints, including camera motion $\pmb{\mu}_t^{sce}$ and object motion $\pmb{\mu}_t^{obj}$ . We then obtain the rendered scene novel view $\mathbf{I}_t^{sce}$ and object novel view $\mathbf{I}_t^{obj}$ as in Equation (3). The separate optical flows, $\mathbf{F}_{s\rightarrow t}^{sce}$ and $\mathbf{F}_{s\rightarrow t}^{obj}$ can also be obtained as in Equation (5). The optical flows in $\mathbf{F}_{s\rightarrow t}$ are mixed by the values in $\mathbf{F}_{s\rightarrow t}^{sce}$ and $\mathbf{F}_{s\rightarrow t}^{obj}$ in terms of mask $\mathbf{M}_s$ to get the final optical flow maps containing camera motion and dynamic objects for training. + +We can then use the bilinear interpolation to get the new object masks $\mathbf{M}_t$ and $\mathbf{M}_t^{obj}$ under the new viewpoints $\pmb{\mu}_t$ and $\pmb{\mu}_t^{obj}$ via bilinear sampling from $\mathbf{M}_s$ . Pixels in the new merged image are also selected according to the content masks $1 - \mathbf{M}_t$ and $\mathbf{M}_t^{obj}$ from $\mathbf{I}_t^{sce}$ and $\mathbf{I}_t^{obj}$ . Then, a simple inpainting strategy [46] is used to fill the empty area in the new image with an inpainting mask calculated by $\mathbf{M}_{fill} = \mathbf{M}_t\odot (1 - \mathbf{M}_t^{obj})$ . + +Depth-Aware Inpainting Although merged images give a realistic visual effect, depth changes caused by camera motion and object motion can also cause unnatural occlusions. To solve this problem, we use volume rendering to obtain the depth $\mathbf{D}_t^{sce}$ of the scene novel view: + +$$ +\mathbf {D} _ {t} = \sum_ {n = 1} ^ {N} \left(\mathbf {d} _ {n} ^ {\prime} \boldsymbol {\alpha} _ {n} ^ {\prime} \prod_ {m = 1} ^ {n - 1} \left(1 - \boldsymbol {\alpha} _ {m} ^ {\prime}\right)\right), \tag {7} +$$ + +and the depth of the object novel view $\mathbf{D}_t^{obj}$ can be obtained in the same way. We then utilize both depths to compute the occupation mask between the novel views: + +$$ +\mathbf {M} _ {o c c} = \left(1 - \mathbf {M} _ {t}\right) \odot \mathbf {M} _ {t} ^ {o b j} \odot \left(\mathbf {D} _ {t} < \mathbf {D} _ {t} ^ {o b j}\right), \tag {8} +$$ + +which indicates the background areas in front of the object. Therefore, we are able to restore the coincidence area between the object and the background in the new image $\mathbf{I}_t$ . + +Figure 3 provides a detailed illustration of the incremental effects of MPI-Flow with and without independent object motion and depth-aware inpainting. Novel view images and optical flows from single-view images can be generated with MPI-Flow and only camera motion, as shown in Figures 3(a) and 3(b). However, camera motion alone does not match the complex optical flows in real-world scenes. To address this issue, we introduce an independent object motion module, as shown in Figure 3(c), to ensure motion realism. To further enhance motion realism and address occlusion caused by object motion, we apply the depth-aware inpainting module, as shown in Figure 3(d). + +# 4. Experiments + +# 4.1. Datasets + +FlyingChairs [9] and FlyingThings3D [18] are both popular synthetic datasets that train optical flow models. As a standard practice, we use "Ch" and "Th" respectively to represent the two datasets, and "Ch→Th" means training first on "Ch" and fine-tuning on "Th". By default, we use the RAFT pre-trained on "Ch→Th" to be fine-tuned on the generated datasets and evaluated on labeled datasets. + +COCO [27] is a collection of single still images and ground truth with labels for object detection or panoptic segmentation tasks. We sample 20k single-view still images from the train2017 split following Depthstillation [1] to generate virtual images and optical flow maps. + +DAVIS [37] provides high-resolution videos and it is widely used for video object segmentation. We use all the 10581 images of the unsupervised 2019 challenge to generate datasets by MPI-Flow and other state-of-the-art optical flow dataset generation methods. + +KITTI2012 [11] and KITTI2015 [34] are well-known benchmarks for optical flow estimation. There are multi-view extensions (4,000 for training and 3,989 for testing) + +![](images/18aa294b4c43e2cfbbfb26d4f0b4339699614dabe1ce6839da29630733a0f5b5.jpg) + +![](images/483db86c9c2fd68689ceb6a2e941c4a4d1f64516dc3c1df0c175456ee79e1724.jpg) +(a) Source Image + +![](images/4eefc23d3c4e9dc0b40e238ae4ab1584fdf26a5c403f7fefd2a52d53aeeed15c.jpg) +(b) + Camera Motion + +![](images/1cb0d434562663e28645fa986f02ffedb6a994c4bd19a31bcee779da3164b59c.jpg) +(c) + Independent Object Motion +(d) + Depth-Aware Inpainting +Figure 3: Visualization of incrementally adding different modules to improve the realism of the generated data. + +datasets with no ground truth. We use the multi-view extension images (training and testing) of KITTI 2015 to generate datasets, separately. By default, we evaluate the trained models on KITTI 12 training set and KITTI 15 training set in the tables following [1] and [12], abbreviated as "KITTI 15" and "KITTI 12" in the following tables. + +Sintel [5] is derived from the open-source 3D animated short film Sintel. The dataset has 23 different scenes. The stereo images are RGB, while the disparity is grayscale. Although not a real-world dataset, we use it to verify the model's generalization across domains. + +# 4.2. Implementation Details + +Firstly, we provide a description of the learning-based optical flow estimation models that were utilized in our experiments. Subsequently, we outline the experimental parameters and setup along with the evaluation formulation. + +Optical Flow networks. To evaluate how effective our generated data are at training optical flow models, we select RAFT [45], which represents state-of-the-art architecture for supervised optical flow and has excellent generalization capability. By default, we train RAFT on generated data for 200K steps with a learning rate of $1 \times 10^{-4}$ and weight decay of $1 \times 10^{-5}$ , batch size of 6, and $288 \times 960$ image crops. This configuration is the default setting of RAFT fitting on KITTI with two GPUs but four times the number of training steps, following [12]. For the rest of the setup, we use the official implementation of RAFT without any modifications. All evaluations are performed on a single NVIDIA + +
Image SourceMethodSintel.CSintel.FKITTI 12KITTI 15
EPE ↓>3 ↓EPE ↓>3 ↓EPE ↓F1 ↓EPE ↓F1 ↓
COCODepthstillation [1]1.875.313.219.251.746.813.4513.08
RealFlow [12]N/AN/AN/AN/AN/AN/AN/AN/A
MPI-Flow (ours)1.874.593.168.291.364.913.4410.66
DAVISDepthstillation [1]2.707.523.8112.061.816.893.7913.22
RealFlow [12]1.734.813.478.711.596.083.5512.52
MPI-Flow (ours)1.794.773.068.561.415.363.3210.47
KITTI 15 TestDepthstillation [1]4.029.084.9613.231.775.973.9913.34
RealFlow [12]3.737.365.5311.311.275.162.438.86
MPI-Flow (ours)2.255.253.658.891.244.512.167.30
KITTI 15 TrainDepthstillation [1]2.847.184.3111.241.675.71{2.99}{9.94}
RealFlow [12]4.067.684.7811.441.255.02{2.17}{8.64}
MPI-Flow (ours)2.415.393.829.111.264.66{1.88}{7.16}
+ +# GeForce RTX 3090 GPU1. + +Virtual Camera Motion. To generate the novel view images from COCO and DAVIS, we adopt the same settings in [1] to build the virtual camera. For KITTI, we empirically build the camera motion with three scalars where $t_x, t_y$ are in $[-0.2, 0.2]$ and $t_z$ are in $[0.1, 0.35]$ . We build the camera rotation with three Euler angles $a_x, a_y, a_z$ in $[- \frac{\pi}{90}, \frac{\pi}{90}]$ . We use single camera motion for each image from COCO but multiple camera motions ( $\times 4$ by default) from DAVIS and KITTI as in [12], due to the small number of images and the homogeneity of the scene in video data. We show how the number of camera motions impacts the optical flow network performance in the discussion. + +Evaluation Metrics. We report evaluation results on the average End-Point Error (EPE) and two error rates, respectively the percentage of pixels with an absolute error greater than $3 (> 3)$ or both absolute and relative errors greater than 3 and $5\%$ respectively (Fl) on all pixels. + +# 4.3. Comparison with State-of-the-art Methods + +In this section, we evaluate the effectiveness of the MPI-Flow generation pipeline on public benchmarks. We will highlight the best results in **bold** and **underline** the second-best if necessary among methods trained in fair conditions. + +Comparison with Dataset Generation Methods. As a method for generating datasets from real-world images, we compare MPI-Flow with Depthstillation [1] and RealFlow [12], which are representative works in real-world dataset generation. In order to evaluate the effectiveness + +Table 1: The cross-dataset validation results and comparisons with other dataset generation methods from real images or videos are presented in this study. The "Image Source" column indicates the dataset used for optical flow training data generation. The evaluation results of RAFT trained on different datasets using different methods are reported. In cases where RealFlow fails to work on single-view images from COCO, the study indicates "N/A". The curly braces "\{\}" represent the use of the unlabeled evaluation set, which is the KITTI 15 training set in this table. + +
DatasetKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
Ch→Th [18]2.088.865.0017.44
dDAVIS [1]1.816.893.7913.22
MF-DAVIS1.616.413.7712.40
dCOCO [1]1.806.663.8012.44
MF-COCO1.596.223.6811.95
+ +Table 2: Results on RAFT trained from scratch under the same setting. "dX" are from Depthstillation [1] while "MF-X" are from our proposed MPI-Flow + +of MPI-Flow, we follow the procedures of Depthstillation and RealFlow to construct training sets from four different datasets, including COCO, DAVIS, KITTI 15 multi-view train set, and KITTI 15 multi-view test set. To ensure fair comparisons, we conduct experiments with a similar number of training sets as our competitors. Specifically, for DAVIS and KITTI, we generate four motions for each image to match RealFlow, which trains RAFT for four EM iterations with four times the amount of data. For COCO, we follow the exact same setup as Depthstillation. Since Depthstillation does not provide details for KITTI 15 train, we use its default settings to obtain the results. Trained models are evaluated on the training sets of Sintel, KITTI 12, and KITTI 15. We report the evaluation results of models with the best performance in the paper for Depthstillation and RealFlow. Furthermore, we conduct cross-dataset experiments where RAFT is trained with one generated dataset and evaluated with another. + +As shown in Table 1, even with the same amount of data, our approach gains significant improvements and generalization over multiple datasets. When trained and tested with + +![](images/6c9872874dbce6f88dc9e94435216586fb035fe14830981d04e3325f26840b4f.jpg) + +![](images/0d0e458a409fe6f74c3a7be43be012010775bfa27f6a9e5f0c16f4c9bed619f3.jpg) +(a) Source Image + +![](images/4a4f571291d256910cb7fdc5bcc3ac9761bf72e291cefb9b363bdd491dd55749.jpg) + +![](images/2263f6bc8e0fafe00c29c4a7545b33396f4f470f86c4198c3fc7583987ad8219.jpg) +(b) Depthstillation + +![](images/90a4d2644a51927d4c2d271836f4bca126553384389c6e575226f3252fb3cfc7.jpg) + +![](images/37e6111293e159bdc603bdbcf8e064a98e848886eeb62eb16b86b68a313bafde.jpg) +(c) RealFlow + +![](images/cdb122339af00be3468c779f56d2f6fc76330957cc409b378110940a9c6f6432.jpg) + +![](images/1d7f34f3b51b136a1c0e0fdcf33da02c40b9882f16a43b71dc527aa19e04c0c2.jpg) +(d) MPI-Flow (ours) + +![](images/da6707e7b80286d946ca8c549414289233de634768daf029b1f59ede4fe206b6.jpg) +Figure 4: Qualitative results of generated images and optical flows from the KITTI 2015 training set. (a) contains the input source images. (b), (c), and (d) contain generated images of RealFlow [12], Depthstillation [1], and our proposed MPI-Flow. MPI-Flow eliminates the artifact in the new image and guarantees image realism. (Best viewed with zoom-in) + +![](images/81e55a0103cf6eb67b950b31ad9a5cff5ded0d1f816cc7b41613195ae6690ffc.jpg) +(a) Source Image from KITTI 15 +(b) Depthstillation + +![](images/3e09a57c2ded5c79c814a00c1d54c4c332a422696f67ae6ee0144ab751beb139.jpg) +(c) RealFlow + +![](images/7831bbf1fc3879e5e55f8195f3f4a80f7a08b71d41b6902bed7c2b671f65460c.jpg) +(d) MPI-Flow (ours) + +![](images/1caead2e32017dd6cf68a96d50cc32de4eb68d37e269d309d72705545bfab18c.jpg) +Figure 5: Visualization of generated images with Depthstillation, RealFlow, and our proposed MPI-Flow from KITTI. Note that RealFlow generates such data using two frames with estimated optical flow. +(a) Depthstillation +Figure 6: Visualization of generated images with Depthstillation and our proposed MPI-Flow using a single view. + +![](images/0ec822264feb48785c74b26e0f1943736703b95cef9bf3c648bb0635ccc43d8f.jpg) +(b) MPI-Flow (ours) + +the same KITTI 15 Train image source, our EPE outperforms the second-best by a remarkable 0.29. When trained and tested with different image sources, our MPI-Flow demonstrates clear improvements over the competitors on almost all the evaluation settings. Notably, MPI-Flow achieves much better performance, even though RealFlow requires two consecutive frames to generate datasets, while + +
MethodKITTI 12KITTI 15
EPE ↓Fl ↓EPE ↓Fl ↓
SemiFlowGAN [25]--{16.02}{38.77}
FlowSupervisor [20]--{3.35}{11.12}
DistractFlow [21]--{3.01}{11.7}
Meta-Learning [36]--{2.81}-
SimFlow [19]--{5.19}-
ARFlow [28]1.44-{2.85}-
UFlow [22]1.68-2.719.05
UpFlow [33]1.27-2.45-
SMURF [42]--{2.00}{6.42}
MPI-Flow1.184.46{1.80}{6.63}
+ +Table 3: Comparison with semi-supervised and unsupervised methods. $\cdot -$ ’ indicates no results reported. + +MPI-Flow needs only one still image. + +It is worth comparing MPI-Flow with Depthstillation under the same settings to evaluate their performance. For this comparison, we use the exact same settings as Depthstillation. Specifically, we generate MPI-Flow datasets with 1) no object motion, 2) the same camera parameters, 3) one camera motion per image, and 4) without pre-training on $\mathrm{Ch}\rightarrow \mathrm{Th}$ . The datasets generated are named MF-DAVIS and MF-COCO, while dCOCO and dDAVIS are generated from Depthstillation. The models are trained from scratch with the respective datasets. RealFlow is not included in this table as it requires a pre-trained optical flow model to generate datasets. The evaluation results are shown in Table 2. Our method outperforms Depthstillation with significant improvements on both COCO and DAVIS, demonstrating the importance of image realism. + +Comparison with Unsupervised Methods. Another way to utilize real-world data is through unsupervised learning, which learns optical flow pixels directly without the need for optical flow labels. In order to further demonstrate the effectiveness of MPI-Flow, we compare our method with the existing literature on unsupervised methods. The results of this comparison can be seen in Table 3. All methods are evaluated under the condition that only images from + +
Dynamic ObjectsDepth-Aware InpaintingMultiple ObjectsSintel.CSintel.FKITTI 12KITTI 15
EPE ↓>3 ↓EPE ↓>3 ↓EPE ↓Fl ↓EPE ↓Fl ↓
XXX2.586.104.049.671.204.34{2.46}{8.38}
✓XX2.415.393.829.111.264.66{1.88}{7.16}
✓✓X2.375.443.719.051.254.58{1.91}{7.06}
✓✓✓2.205.353.679.031.234.46{1.92}{7.05}
+ +Table 4: Ablation experiments. Settings used are marked with a checkmark. Here we only perform four camera motions per image for these experiments due to the limitation of computational resources. + +
MethodKITTI 15KITTI 15 test
EPE ↓Fl ↓Fl ↓
PWC-Net [44]{2.16}{9.80}9.60
LiteFlowNet [16]{1.62}{5.58}9.38
IRR-PWC [17]{1.63}{5.32}7.65
RAFT [45]{0.63}{1.50}5.10
Depthstillation [12]---
AutoFlow [43]--4.78
RealFlow [12]{0.58}{1.35}4.63
MPI-Flow{0.58}{1.30}4.58
+ +the evaluation set could be used, without access to ground truth labels. For evaluation, we train the RAFT on our generated dataset with images from the KITTI 15 training set. Our MPI-Flow outperform all unsupervised methods in terms of EPE on both the KITTI 12 training set and KITTI 15 training set, with no need for any unsupervised constraints. However, our method performs better on EPE but has slightly lower F1 than SMURF, mainly because SMURF employs multiple frames for training. + +Comparison with Supervised Methods. To further prove the effectiveness of MPI-Flow, we use KITTI 15 train set to fine-tune RAFT pre-trained by our generated dataset with images from KITTI 15 test set. The evaluation results on KITTI 15 train and KITTI 15 test are shown in Table 5. We achieve state-of-art performance on KITTI 2015 test benchmark compared to supervised methods on training RAFT. + +Qualitative Results. Figure 4 show the generated images from the methods utilizing real-world images, as presented in Table 1. In this comparison, we use images from the KITTI 15 dataset as source image input. The images generated by RealFlow [12] and Depthstillation [1] with artifacts degrade the image realism. In contrast, MPI-Flow generates more realistic images than the other two methods. More results are shown in Figures 5 and 6. + +# 4.4. Discussion + +To verify the effectiveness of the proposed MPI-Flow, we discuss the performance of models trained with generated datasets with different settings. We show more discus + +Table 5: Comparison with supervised methods fine-tuned or trained on KITTI 15 train set. + +
Motions +Per ImageKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
11.294.582.027.35
41.234.461.927.05
101.214.491.827.02
201.204.411.796.86
401.184.461.806.63
+ +Table 6: Effect of amount of virtual camera motions (training pairs) per source image. + +
Objects +Per ImageKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
11.254.581.917.06
21.264.762.027.19
41.234.461.927.05
+ +Table 7: Effect of amount of dynamic objects per image. + +sion and evaluation results in the supplementary material. + +Object Motion and Depth-Aware Inpainting. We conduct a series of ablation studies to analyze the impact of different choices in our proposed MPI-Flow for new image synthesis, including object motion, depth-aware inpainting, and multiple objects. "Multiple objects" indicates multiple moving objects in each image. To measure the impact of these factors, we generate new images from the KITTI 15 training set to train RAFT and evaluate them on the KITTI 12 training set and KITTI 15 training set. Because there are multiple combinations of these factors, we test by incrementally adding components of our approach, as shown in Table 4. In the first row, we show the performance achieved by generating new images without dynamic objects, thus assuming that optical flow comes from camera motion only. Then we incrementally add single-object motion, depth-aware inpainting, and multi-object motion to model a more realistic scenario. There are considerable improvements in almost all datasets on various metrics, except for the KITTI 12 training set, possibly due to the infrequent dynamic object motion in this dataset. The EPE on KITTI 15 remains relatively stable within the normal margin after adding the depth-aware inpainting module and the multi-object trick. + +Camera Motion Parameters. We also conduct a series of + +
tzKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
0.1 ~ 0.451.254.60{1.79}{6.68}
0.1 ~ 0.351.184.46{1.80}{6.63}
0.1 ~ 0.251.194.50{1.86}{6.71}
0.0 ~ 0.351.124.32{1.94}{6.92}
+ +Table 8: Effect of motion parameters ${t}_{z}$ . + +
txandtyKITTI 12KITTI 15
EPE ↓Fl ↓EPE ↓Fl ↓
-0.3 ~ 0.31.224.42{1.92}{6.83}
-0.2 ~ 0.21.184.46{1.80}{6.63}
-0.1 ~ 0.11.324.99{1.98}{7.02}
+ +Table 9: Effect of motion parameters ${t}_{x}$ and ${t}_{y}$ . + +
DatasetKITTI 12KITTI 15
EPE ↓Fl ↓EPE ↓Fl ↓
Ch→Th [18]4.1421.3810.3533.67
dDAVIS [1]2.8111.296.8821.87
MF-DAVIS2.7011.256.9220.97
dCOCO [1]3.1613.308.4926.06
MF-COCO3.0211.208.2223.40
+ +ablation studies to analyze the impact of different parameters on camera motions. We first show the effect of $t_z$ , which indicates the range of moving forward and backward distances, as shown in Table 4. We set the minimum $t_z$ to 0.1 by default, considering that most cameras on vehicles only move forward in the KITTI dataset. We also show the effect of $t_x$ and $t_y$ , representing the distance from left to right and from up to down, respectively. Because there are multiple combinations of parameters, we only test a specific parameter of our method in isolation. Settings used by default are underlined. The results show that a more reasonable range of camera motion leads to better performance. + +Model Architectures The default model used in our paper is RFAT [45]. Table 10 shows that our proposed MPI-Flow also works for PWC-Net [44] compared with depthstillation [1] in a fair setting. We generate data from COCO and DAVIS and train PWC-Net, in which the results are still better than PWC-Net trained on $\mathrm{Ch} \rightarrow \mathrm{Th}$ or datasets generated from depthstillation. + +Amount of Virtual Motions. We can generate multiple camera motions with multiple dynamic objects for any given single image and thus a variety of paired images and ground-truth optical flow maps. Thus we can increase the number of camera motions to generate more data. Table 6 shows the impact of different amounts of camera motions on model performance. Interestingly, MPI-Flow with 4 mo + +Table 10: Results on PWC-Net trained on generated datasets from scratch under the same setting. + +
DatasetQuantityKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
Ch→Th [18]47K2.088.865.0017.44
MF-COCO20K1.596.223.6811.95
MF-COCO120K1.515.943.4111.16
+ +Table 11: Effect of amount of source images. + +tions per image already allows for strong generalization to real domains, outperforming the results achieved using synthetic datasets shown in the previous evaluation results. Increasing the motions per image by factors 10 and 20 both lead to better performance on KITTI 12 and KITTI 15 compared to 4 and 1. Using 40 motions per image gives the best performance on KITTI 15 in terms of Fl. It indicates that a more variegate image content in the generated dataset may be beneficial for generalization to real applications. Table 7 shows the effect of amounts of dynamic objects on model performance. Increasing the number of dynamic objects improves the performance of the model on KITTI 12 but slightly decreases it on KITTI 15 in terms of EPE. + +Quantity of Source Images The number of source images affects the scene diversity of the generated dataset. Empirically, more source images will be more conducive to model learning, as verified in Table 11. We verify the effect of the number of source images on the MF-COCO. The model performance is significantly improved by increasing the number of source images. + +# 5. Conclusion + +In this paper, we present a new framework for generating optical flow datasets, which addresses two main challenges: image realism and motion realism. Firstly, we propose an MPI-based image rendering pipeline that generates realistic images with corresponding optical flows from novel viewpoints. This pipeline utilizes volume rendering to address image artifacts and holes, leading to more realistic images. Secondly, we introduce an independent object motion module that separates dynamic objects from the static scene. By decoupling object motion, we further improve motion realism. Additionally, we design a depth-aware inpainting module that handles unnatural occlusions caused by object motion in the generated images. Through these novel designs, our approach achieves superior performance on real-world datasets compared to both unsupervised and supervised methods for training learning-based models. + +Acknowledgments This work was supported by the National Natural Science Foundation of China (12202048, 62171038, and 62171042), the R&D Program of Beijing Municipal Education Commission (KZ202211417048), and the Fundamental Research Funds for the Central Universities. + +# References + +[1] Filippo Aleotti, Matteo Poggi, and Stefano Mattoccia. Learning optical flow from still images. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 15201-15211, 2021. 1, 2, 3, 5, 6, 7, 8, 9 +[2] Simon Baker, Daniel Scharstein, JP Lewis, Stefan Roth, Michael J Black, and Richard Szeliski. A database and evaluation methodology for optical flow. International Journal of Computer Vision (IJCV), 92(1):1-31, 2011. 1, 2 +[3] Thomas Brox, Christoph Bregler, and Jitendra Malik. Large displacement optical flow. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 41-48, 2009. 1 +[4] D. J. Butler, J. Wulff, G. B. Stanley, and M. J. Black. A naturalistic open source movie for optical flow evaluation. In the European Conference on Computer Vision (ECCV), pages 611-625, 2012. 1 +[5] Daniel J Butler, Jonas Wulff, Garrett B Stanley, and Michael J Black. A naturalistic open source movie for optical flow evaluation. In the European Conference on Computer Vision (ECCV), pages 611-625, 2012. 5 +[6] Gustavo Sutter P. Carvalho, Diogo Carbonera Luvizon, Antonio Joia Neto, Andre G. C. Pacheco, and Otavio Augusto Bizetto Penatti. Learning multiplane images from single views with self-supervision. In British Machine Vision Conference (BMVC), 2021. 2 +[7] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1290–1299, 2022. 4 +[8] Jiyu Cheng, Yuxiang Sun, and Max Q-H Meng. Improving monocular visual slam in dynamic environments: an optical-flow-based approach. Advanced Robotics, 33(12):576-589, 2019. 1 +[9] Alexey Dosovitskiy, Philipp Fischer, Eddy Ilg, Philip Hausser, Caner Hazirbas, Vladimir Golkov, Patrick Van Der Smagt, Daniel Cremers, and Thomas Brox. Flownet: Learning optical flow with convolutional networks. In the IEEE International Conference on Computer Vision (ICCV), pages 2758-2766, 2015. 1, 2, 5 +[10] Bo Du, Shihan Cai, and Chen Wu. Object tracking in satellite videos based on a multiframe optical flow tracker (j-stars). the IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 12(8):3043-3055, 2019. 1 +[11] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the kitti vision benchmark suite. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3354-3361, 2012. 1, 2, 5 +[12] Yunhui Han, Kunming Luo, Ao Luo, Jiangyu Liu, Haoqiang Fan, Guiming Luo, and Shuaicheng Liu. Realflow: Embased realistic optical flow dataset generation from videos. In the European Conference on Computer Vision (ECCV), pages 288-305, 2022. 1, 2, 3, 5, 6, 7, 8 +[13] Yuxuan Han, Ruicheng Wang, and Jiaolong Yang. Single-view synthesis in the wild with learned adaptive multiplane images. In ACM SIGGRAPH, 2022. 2, 3, 4 + +[14] Toshihide Hanari, Kuniaki Kawabata, and Keita Nakamura. Image selection method from image sequence to improve computational efficiency of 3d reconstruction: Analysis of inter-image displacement based on optical flow for evaluating 3d reconstruction performance. In the IEEE International Symposium on System Integration (SII), pages 1041-1045, 2022. 1 +[15] Anders Heyden and Marc Pollefeys. Multiple view geometry. Emerging topics in computer vision, 3:45-108, 2005. 4 +[16] Tak-Wai Hui, Xiaou Tang, and Chen Change Loy. Liteflownet: A lightweight convolutional neural network for optical flow estimation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 8981-8989, 2018. 2, 8 +[17] Junhwa Hur and Stefan Roth. Iterative residual refinement for joint optical flow and occlusion estimation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 5754-5763, 2019. 2, 8 +[18] Eddy Ig, Nikolaus Mayer, Tonmoy Saikia, Margret Keuper, Alexey Dosovitskiy, and Thomas Brox. Flownet 2.0: Evolution of optical flow estimation with deep networks. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 2462-2470, 2017. 1, 2, 5, 6, 9 +[19] Woobin Im, Tae-Kyun Kim, and Sung-Eui Yoon. Unsupervised learning of optical flow with deep feature similarity. In the European Conference on Computer Vision (ECCV), pages 172-188, 2020. 7 +[20] Woobin Im, Sebin Lee, and Sung-Eui Yoon. Semi-supervised learning of optical flow by flow supervisor. In the European Conference on Computer Vision (ECCV), pages 302-318, 2022. 7 +[21] Jisoo Jeong, Hong Cai, Risheek Garrepalli, and Fatih Porikli. Distractflow: Improving optical flow estimation via realistic distractions and pseudo-labeling. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 13691-13700, 2023. 7 +[22] Rico Jonschkowski, Austin Stone, Jonathan T Barron, Ariel Gordon, Kurt Konolige, and Anelia Angelova. What matters in unsupervised optical flow. In the European Conference on Computer Vision (ECCV), pages 557-572, 2020. 7 +[23] Artúr I Károly, Renata Nagyné Elek, Tamás Haidegger, Károly Széll, and Péter Galambos. Optical flow-based segmentation of moving objects for mobile robot navigation using pre-trained deep learning models. In the IEEE International Conference on Systems, Man and Cybernetics (SMC), pages 3080-3086, 2019. 1 +[24] Filippos Kokkinos and Iasonas Kokkinos. Learning monocular 3d reconstruction of articulated categories from motion. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1737-1746, 2021. 1 +[25] Wei-Sheng Lai, Jia-Bin Huang, and Ming-Hsuan Yang. Semi-supervised learning for optical flow with generative adversarial networks. Advances in Neural Information Processing Systems (NIPS), 30, 2017. 7 +[26] Jiaxin Li, Zijian Feng, Qi She, Henghui Ding, Changhu Wang, and Gim Hee Lee. Mine: Towards continuous depth + +MPI with nerf for novel view synthesis. In the IEEE International Conference on Computer Vision (ICCV), pages 12578-12588, 2021. 3 +[27] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In the European Conference on Computer Vision (ECCV), pages 740-755, 2014. 5 +[28] Liang Liu, Jiangning Zhang, Ruifei He, Yong Liu, Yabiao Wang, Ying Tai, Donghao Luo, Chengjie Wang, Jilin Li, and Feiyue Huang. Learning by analogy: Reliable supervision from transformations for unsupervised optical flow estimation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 6489-6498, 2020. 7 +[29] Yubao Liu and Jun Miura. Rdmo-slam: Real-time visual slam for dynamic environments using semantic label prediction with optical flow. IEEE Access, 9:106981-106997, 2021. 1 +[30] Stephen Lombardi, Tomas Simon, Jason Saragih, Gabriel Schwartz, Andreas Lehrmann, and Yaser Sheikh. Neural volumes: Learning dynamic renderable volumes from images. arXiv preprint arXiv:1906.07751, 2019. 2 +[31] Ao Luo, Fan Yang, Xin Li, and Shuaicheng Liu. Learning optical flow with kernel patch attention. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 8906-8915, 2022. 2 +[32] Ao Luo, Fan Yang, Kunming Luo, Xin Li, Haoqiang Fan, and Shuaicheng Liu. Learning optical flow with adaptive graph reasoning. In the AAAI Conference on Artificial Intelligence, volume 36, pages 1890-1898, 2022. 2 +[33] Kunming Luo, Chuan Wang, Shuaicheng Liu, Haoqiang Fan, Jue Wang, and Jian Sun. Upflow: Upsampling pyramid for unsupervised optical flow learning. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1045-1054, 2021. 7 +[34] Moritz Menze and Andreas Geiger. Object scene flow for autonomous vehicles. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3061-3070, 2015. 1, 2, 5 +[35] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021. 2 +[36] Chaerin Min, Taehyun Kim, and Jongwoo Lim. Meta-learning for adaptation of deep optical flow networks. In the IEEE Winter Conference on Applications of Computer Vision (WACV), pages 2145-2154, 2023. 7 +[37] Federico Perazzi, Jordi Pont-Tuset, Brian McWilliams, Luc Van Gool, Markus Gross, and Alexander Sorkine-Hornung. A benchmark dataset and evaluation methodology for video object segmentation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 724-732, 2016. 5 +[38] René Ranftl, Katrin Lasinger, David Hafner, Konrad Schindler, and Vladlen Koltun. Towards robust monocular depth estimation: Mixing datasets for zero-shot cross-dataset + +transfer. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 44(3):1623-1637, 2020. 4 +[39] Chris Rockwell, David F Fouhey, and Justin Johnson. Pixelsynth: Generating a 3d-consistent experience from a single image. In the IEEE International Conference on Computer Vision (ICCV), pages 14104-14113, 2021. 3 +[40] Robin Rombach, Patrick Esser, and Björn Ommer. Geometry-free view synthesis: Transformers and no 3d priors. In the IEEE International Conference on Computer Vision (ICCV), pages 14356-14366, 2021. 3 +[41] Nitin J Sanket, Chahat Deep Singh, Cornelia Fermüller, and Yiannis Aloimonos. Prgflow: Unified swap-aware deep global optical flow for aerial robot navigation. *Electronics Letters*, 57(16):614–617, 2021. 1 +[42] Austin Stone, Daniel Maurer, Alper Ayvaci, Anelia Angelova, and Rico Jonschkowski. Smurf: Self-teaching multiframe unsupervised raft with full-image warping. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3887-3896, 2021. 7 +[43] Deqing Sun, Daniel Vlasic, Charles Herrmann, Varun Jampani, Michael Krainin, Huiwen Chang, Ramin Zabih, William T Freeman, and Ce Liu. Autoflow: Learning a better training set for optical flow. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 10093-10102, 2021. 2, 8 +[44] Deqing Sun, Xiaodong Yang, Ming-Yu Liu, and Jan Kautz. Pwc-net: Cnns for optical flow using pyramid, warping, and cost volume. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 8934-8943, 2018. 1, 2, 8, 9 +[45] Zachary Teed and Jia Deng. Raft: Recurrent all-pairs field transforms for optical flow. In the European Conference on Computer Vision (ECCV), pages 402-419, 2020. 1, 2, 5, 8, 9 +[46] Alexandru Telea. An image inpainting technique based on the fast marching method. Journal of graphics tools, 9(1):23-34, 2004. 4 +[47] Richard Tucker and Noah Snively. Single-view view synthesis with multiplane images. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 551-560, 2020. 2, 3 +[48] Shubham Tulsiani, Richard Tucker, and Noah Snavely. Layer-structured 3d scene inference via view synthesis. In the European Conference on Computer Vision (ECCV), pages 302–317, 2018. 2 +[49] Philippe Weinzaepfel, Jerome Revaud, Zaid Harchaoui, and Cordelia Schmid. Deepflow: Large displacement optical flow with deep matching. In the IEEE International Conference on Computer Vision (ICCV), pages 1385-1392, 2013. 1, 2 +[50] Christopher Zach, Thomas Pock, and Horst Bischof. A duality based approach for realtime tv-l 1 optical flow. In Pattern Recognition, pages 214-223, 2007. 1 +[51] Jimuyang Zhang, Sanping Zhou, Xin Chang, Fangbin Wan, Jinjun Wang, Yang Wu, and Dong Huang. Multiple object tracking by flowing and fusing. arXiv preprint arXiv:2001.11180, 2020. 1 +[52] Tianwei Zhang, Huayan Zhang, Yang Li, Yoshihiko Nakamura, and Lei Zhang. Flowfusion: Dynamic dense rgb-d + +slam based on optical flow. In the IEEE International Conference on Robotics and Automation (ICRA), pages 7322-7328, 2020. 1 +[53] Tinghui Zhou, Richard Tucker, John Flynn, Graham Fyffe, and Noah Snavely. Stereo magnification: Learning view synthesis using multiplane images. In ACM SIGGRAPH, 2018. 2 +[54] Yuemei Zhou, Gaochang Wu, Ying Fu, Kun Li, and Yebin Liu. Cross-mpi: Cross-scale stereo for image super-resolution using multiplane images. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 14842-14851, 2021. 2 \ No newline at end of file diff --git a/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/images.zip b/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..817c3a50e98ce26dc5f99995f071714e3a98cdb9 --- /dev/null +++ b/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:e68149b8c11b98e9b3907bc82d001b6b168fd0db92c3e5e3cb4f485dfcde8e9d +size 785270 diff --git a/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/layout.json b/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..18f979752a8db59b1ab2028a1ae2d9e4bf7cffd1 --- /dev/null +++ b/2023/MPI-Flow_ Learning Realistic Optical Flow with Multiplane Images/layout.json @@ -0,0 +1,10933 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 86, + 103, + 507, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 86, + 103, + 507, + 121 + ], + "spans": [ + { + "bbox": [ + 86, + 103, + 507, + 121 + ], + "type": "text", + "content": "MPI-Flow: Learning Realistic Optical Flow with Multiplane Images" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 89, + 142, + 171, + 158 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 89, + 142, + 171, + 158 + ], + "spans": [ + { + "bbox": [ + 89, + 142, + 171, + 158 + ], + "type": "text", + "content": "Yingping Liang" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 220, + 143, + 285, + 157 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 220, + 143, + 285, + 157 + ], + "spans": [ + { + "bbox": [ + 220, + 143, + 285, + 157 + ], + "type": "text", + "content": "Jiaming Liu2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 167, + 158, + 323, + 172 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 167, + 158, + 323, + 172 + ], + "spans": [ + { + "bbox": [ + 167, + 158, + 323, + 172 + ], + "type": "text", + "content": "1Beijing Institute of Technology" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 334, + 143, + 408, + 157 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 334, + 143, + 408, + 157 + ], + "spans": [ + { + "bbox": [ + 334, + 143, + 408, + 157 + ], + "type": "text", + "content": "Debing Zhang" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 335, + 158, + 427, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 335, + 158, + 427, + 171 + ], + "spans": [ + { + "bbox": [ + 335, + 158, + 427, + 171 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 335, + 158, + 427, + 171 + ], + "type": "text", + "content": "Xiaohongshu Inc." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 459, + 143, + 507, + 157 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 459, + 143, + 507, + 157 + ], + "spans": [ + { + "bbox": [ + 459, + 143, + 507, + 157 + ], + "type": "text", + "content": "Ying Fu" + }, + { + "bbox": [ + 459, + 143, + 507, + 157 + ], + "type": "inline_equation", + "content": "^{1*}" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 143, + 198, + 192, + 211 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 198, + 192, + 211 + ], + "spans": [ + { + "bbox": [ + 143, + 198, + 192, + 211 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 225, + 290, + 596 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 225, + 290, + 596 + ], + "spans": [ + { + "bbox": [ + 46, + 225, + 290, + 596 + ], + "type": "text", + "content": "The accuracy of learning-based optical flow estimation models heavily relies on the realism of the training datasets. Current approaches for generating such datasets either employ synthetic data or generate images with limited realism. However, the domain gap of these data with real-world scenes constrains the generalization of the trained model to real-world applications. To address this issue, we investigate generating realistic optical flow datasets from real-world images. Firstly, to generate highly realistic new images, we construct a layered depth representation, known as multiplane images (MPI), from single-view images. This allows us to generate novel view images that are highly realistic. To generate optical flow maps that correspond accurately to the new image, we calculate the optical flows of each plane using the camera matrix and plane depths. We then project these layered optical flows into the output optical flow map with volume rendering. Secondly, to ensure the realism of motion, we present an independent object motion module that can separate the camera and dynamic object motion in MPI. This module addresses the deficiency in MPI-based single-view methods, where optical flow is generated only by camera motion and does not account for any object movement. We additionally devise a depth-aware inpainting module to merge new images with dynamic objects and address unnatural motion occlusions. We show the superior performance of our method through extensive experiments on real-world datasets. Moreover, our approach achieves state-of-the-art performance in both unsupervised and supervised training of learning-based models. The code will be made publicly available at: https://github.com/Sharpiless/MPI-Flow." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 622, + 128, + 634 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 622, + 128, + 634 + ], + "spans": [ + { + "bbox": [ + 47, + 622, + 128, + 634 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 643, + 287, + 692 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 643, + 287, + 692 + ], + "spans": [ + { + "bbox": [ + 47, + 643, + 287, + 692 + ], + "type": "text", + "content": "Optical flow refers to the precise calculation of per-pixel motion between consecutive video frames. Its applications span a wide range of fields, including object tracking [10, 51], robot navigation [23, 41], three-dimensional (3D)" + } + ] + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 307, + 198, + 384, + 281 + ], + "blocks": [ + { + "bbox": [ + 307, + 198, + 384, + 281 + ], + "lines": [ + { + "bbox": [ + 307, + 198, + 384, + 281 + ], + "spans": [ + { + "bbox": [ + 307, + 198, + 384, + 281 + ], + "type": "image", + "image_path": "8e844a68db9a3d09806e8131d5e8cb1d25c391c6f54206fefc57145afc1cab14.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 388, + 198, + 465, + 282 + ], + "blocks": [ + { + "bbox": [ + 388, + 198, + 465, + 282 + ], + "lines": [ + { + "bbox": [ + 388, + 198, + 465, + 282 + ], + "spans": [ + { + "bbox": [ + 388, + 198, + 465, + 282 + ], + "type": "image", + "image_path": "03169b595941f422c7b2dde1d3c9bef26c81ae30ee51b95a2ffe63985f4001fe.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 468, + 198, + 545, + 281 + ], + "blocks": [ + { + "bbox": [ + 468, + 198, + 545, + 281 + ], + "lines": [ + { + "bbox": [ + 468, + 198, + 545, + 281 + ], + "spans": [ + { + "bbox": [ + 468, + 198, + 545, + 281 + ], + "type": "image", + "image_path": "d17c980ac8900ca411665bf4d481dbfbd5db15c428133f7aaab0ad3d27fc8c2a.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 308, + 297, + 468, + 390 + ], + "blocks": [ + { + "bbox": [ + 312, + 286, + 380, + 297 + ], + "lines": [ + { + "bbox": [ + 312, + 286, + 380, + 297 + ], + "spans": [ + { + "bbox": [ + 312, + 286, + 380, + 297 + ], + "type": "text", + "content": "(a) Depthstill. [1]" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 392, + 286, + 460, + 297 + ], + "lines": [ + { + "bbox": [ + 392, + 286, + 460, + 297 + ], + "spans": [ + { + "bbox": [ + 392, + 286, + 460, + 297 + ], + "type": "text", + "content": "(b) RealFlow [12]" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 308, + 297, + 468, + 390 + ], + "lines": [ + { + "bbox": [ + 308, + 297, + 468, + 390 + ], + "spans": [ + { + "bbox": [ + 308, + 297, + 468, + 390 + ], + "type": "image", + "image_path": "8c0900c23bc1bc953c01c4f74b3041bddccce71d00bd1153b855a0c44ab3f696.jpg" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 307, + 394, + 544, + 405 + ], + "lines": [ + { + "bbox": [ + 307, + 394, + 544, + 405 + ], + "spans": [ + { + "bbox": [ + 307, + 394, + 544, + 405 + ], + "type": "text", + "content": "(d) Source image and details of generated flows from our method" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 305, + 415, + 547, + 487 + ], + "lines": [ + { + "bbox": [ + 305, + 415, + 547, + 487 + ], + "spans": [ + { + "bbox": [ + 305, + 415, + 547, + 487 + ], + "type": "text", + "content": "Figure 1: Visual comparison of images reveals that our method, when compared with those based on real-world images [1, 12], demonstrates superior image realism. Our method also achieves fine optical flows by employing volume rendering in MPI and separate motions of the camera and object with the independent object motion module." + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_caption" + } + ], + "index": 19 + }, + { + "type": "image", + "bbox": [ + 468, + 297, + 544, + 390 + ], + "blocks": [ + { + "bbox": [ + 490, + 286, + 523, + 297 + ], + "lines": [ + { + "bbox": [ + 490, + 286, + 523, + 297 + ], + "spans": [ + { + "bbox": [ + 490, + 286, + 523, + 297 + ], + "type": "text", + "content": "(c) Ours" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 468, + 297, + 544, + 390 + ], + "lines": [ + { + "bbox": [ + 468, + 297, + 544, + 390 + ], + "spans": [ + { + "bbox": [ + 468, + 297, + 544, + 390 + ], + "type": "image", + "image_path": "7433d0b51b7f26fcdf4cead53a8b2642c8617783130d423ab7dd8ea0b212f879.jpg" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_body" + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 509, + 547, + 629 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 509, + 547, + 629 + ], + "spans": [ + { + "bbox": [ + 304, + 509, + 547, + 629 + ], + "type": "text", + "content": "reconstruction [24, 14], and visual simultaneous localization and mapping (SLAM) [52, 8, 29]. In recent years, with the rapid development of neural networks, learning-based methods [44, 45] have demonstrated significant advances compared to traditional model-based algorithms [3, 49, 50]. Conventional practices primarily rely on synthetic data, as demonstrated by [9, 18, 4]. Synthetic data contains exact optical flow labels and animated images. However, the domain gap between synthetic and real data hinders its further improvements in real-world applications." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 304, + 630, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 547, + 713 + ], + "type": "text", + "content": "Recent studies have aimed to extract optical flow from real-world data by employing hand-made special hardware [2, 11, 34]. However, the rigidly controlled and inefficient collection procedure limits their applicability. To address this issue, Depthstillation [1], and RealFlow [12] have been proposed, which project each pixel in the real-world image onto the novel view frame with the help of random motions" + } + ] + } + ], + "index": 24 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 702, + 201, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 201, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 201, + 712 + ], + "type": "text", + "content": "*Corresponding Author: fuying@bit.edu.cn" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13857" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "type": "text", + "content": "of virtual cameras or estimated flows. Nonetheless, both methods are limited by the lack of image realism, leading to issues such as collisions, holes, and artifacts, as illustrated in Figure 1. These limitations constrain the real-world performance of learning-based optical flow models [44, 45]." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 133, + 287, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 133, + 287, + 251 + ], + "spans": [ + { + "bbox": [ + 46, + 133, + 287, + 251 + ], + "type": "text", + "content": "To achieve higher image realism, we turn our attention to the use of single-view Multiplane Images (MPI) [53, 47, 54, 6, 13]. This line of work demonstrates remarkable single-view image rendering capabilities and effectively reduces collisions, holes, and artifacts commonly found in previous methods [1, 12]. These advancements contribute to higher image realism, prompting a natural question: Can high-realistic MPI methods be adapted to generate high-quality optical flow datasets for training purposes?" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 251, + 288, + 478 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 251, + 288, + 478 + ], + "spans": [ + { + "bbox": [ + 46, + 251, + 288, + 478 + ], + "type": "text", + "content": "To this end, we propose MPI-Flow, aiming to generate realistic optical flow datasets from real-world images. Specifically, we first review the image synthesis pipeline of MPI and devise an optical flow generation pipeline along with image synthesis. In this step, we build an MPI by warping single-view image features onto each layered plane with the predicted color and density. The color and density then be mapped into a realistic new image via volume rendering. With the layered planes, we extract optical flows with virtual camera motions from the rendered image and the real image. Second, as the MPI can only be applied in static scenes, which yield limited motion realism, we propose an independent object motion module and a depth-aware inpainting module to tackle this issue. The independent object motion module decouples dynamic objects from static scenes and applies different virtual camera matrices to calculate the motion of both dynamic and static parts. The depth-aware inpainting module is introduced to remove the object occlusion in the synthesized new image." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 479, + 287, + 562 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 479, + 287, + 562 + ], + "spans": [ + { + "bbox": [ + 46, + 479, + 287, + 562 + ], + "type": "text", + "content": "With MPI-Flow, a large number of single-view images can be used to generate large-scale training datasets with realistic images and motions. This enables learning-based optical flow models better generalization to a wide range of real-world scenes. Extensive experiments on real datasets demonstrate the effectiveness of our approach. In summary, our main contributions are as follows:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 58, + 568, + 286, + 713 + ], + "type": "list", + "angle": 0, + "index": 7, + "blocks": [ + { + "bbox": [ + 59, + 568, + 286, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 568, + 286, + 616 + ], + "spans": [ + { + "bbox": [ + 59, + 568, + 286, + 616 + ], + "type": "text", + "content": "- We are the first to present a novel MPI-based optical flow dataset generation framework, namely MPI-Flow, which can significantly improve the realism of the generated images and motion." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 58, + 623, + 286, + 670 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 623, + 286, + 670 + ], + "spans": [ + { + "bbox": [ + 58, + 623, + 286, + 670 + ], + "type": "text", + "content": "- We present a novel independent object motion module for modeling dynamic objects in MPI, which can model realistic optical flow from camera motion and object motion simultaneously." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 58, + 677, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 677, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 58, + 677, + 286, + 713 + ], + "type": "text", + "content": "- We design a depth-aware inpainting module for realistic image inpainting, which can remove unnatural motion occlusions in generated images." + } + ] + } + ], + "index": 6 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 71, + 392, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 71, + 392, + 83 + ], + "spans": [ + { + "bbox": [ + 306, + 71, + 392, + 83 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 91, + 545, + 126 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 91, + 545, + 126 + ], + "spans": [ + { + "bbox": [ + 305, + 91, + 545, + 126 + ], + "type": "text", + "content": "In this section, we review the most relevant studies on optical flow networks, optical flow dataset generation, and novel view image synthesis methods." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 127, + 545, + 270 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 127, + 545, + 270 + ], + "spans": [ + { + "bbox": [ + 305, + 127, + 545, + 270 + ], + "type": "text", + "content": "Supervised Optical Flow Network. Early methods train deep neural networks to match patches across images [49]. FlowNet [9] first trains convolutional neural networks on the synthetic datasets with optical flow. Moreover, the follow-up methods [16, 17, 18, 32, 31] with advanced modules and network architectures make a significant improvement in supervised optical flow learning, with RAFT [45] representing state-of-the-art. However, generalization remains a cause for concern due to the domain gap between synthetic datasets and real-world applications. To address this problem, our work focuses on generating realistic optical flow datasets from real-world images." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 270, + 545, + 473 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 270, + 545, + 473 + ], + "spans": [ + { + "bbox": [ + 305, + 270, + 545, + 473 + ], + "type": "text", + "content": "Dataset Generation for Optical Flow. The use of fluorescent texture to record motions in real-world scenes is first described in [2] to obtain flow maps. KITTI [11, 34] provides sophisticated training data through complex lidar and camera setups. However, the aforementioned real-world datasets have limited quantities and constrained scenes, making it difficult for models trained using deep supervised learning to generalize to more expansive scenes. Synthesized training pairs, such as those in Flyingchairs [9] and Flyingthings [18], have shown promise for supervised learning. However, moving animated image patches cannot accurately match real-world scenes, leading to domain gaps. AutoFlow [43] introduces a learning-based approach for generating training data by hyper-parameters searching. However, AutoFlow relies on optical flow labels for domain adaptation, which is not practical in most scenarios where ground truth labels are unavailable." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 475, + 545, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 475, + 545, + 628 + ], + "spans": [ + { + "bbox": [ + 305, + 475, + 545, + 628 + ], + "type": "text", + "content": "Two recent works have proposed methods for generating training datasets based on real-world images or videos. The first, called Depthstillation [1], synthesizes paired images by estimating depth and optical flows from a single still image. Optical flows are calculated based on the virtual camera pose and depth. The second method, called RealFlow [12], synthesizes intermediate frames between two frames using estimated optical flows with RAFT. However, both methods use naive image synthesis techniques that fail to meet the demand for realism criteria due to hole-filling and artifacts. In contrast, our method improves on this approach by using a well-designed and modified multiplane image (MPI) technique to obtain realistic images." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 630, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 630, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 630, + 545, + 713 + ], + "type": "text", + "content": "Novel View Synthesis. View synthesis methods aim to generate new images from arbitrary viewpoints by utilizing a given scene. Several classical approaches [48, 30, 53, 35] have been proposed that utilize multiple views of a scene to render novel views with geometric consistency. However, synthesizing novel views from a single image remains challenging due to the limited scene information available." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13858" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 62, + 72, + 531, + 309 + ], + "blocks": [ + { + "bbox": [ + 62, + 72, + 531, + 309 + ], + "lines": [ + { + "bbox": [ + 62, + 72, + 531, + 309 + ], + "spans": [ + { + "bbox": [ + 62, + 72, + 531, + 309 + ], + "type": "image", + "image_path": "de6823920601c4a5726be68fa470e124ef72f03b4ef82d2c20216b5838b136b9.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 327, + 548, + 377 + ], + "lines": [ + { + "bbox": [ + 46, + 327, + 548, + 377 + ], + "spans": [ + { + "bbox": [ + 46, + 327, + 548, + 377 + ], + "type": "text", + "content": "Figure 2: Illustration of our proposed MPI-Flow framework with single-view image " + }, + { + "bbox": [ + 46, + 327, + 548, + 377 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_s" + }, + { + "bbox": [ + 46, + 327, + 548, + 377 + ], + "type": "text", + "content": " as input. We estimate depths to construct MPI where RGB and density of each plane are predicted by neural networks and the flow of each plane is calculated with camera matrixes. Both the novel views and flow maps are rendered by volume rendering and separated by the independent object motion module with novel view object masks. The new image is merged by depth-aware inpainting." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 396, + 289, + 649 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 396, + 289, + 649 + ], + "spans": [ + { + "bbox": [ + 46, + 396, + 289, + 649 + ], + "type": "text", + "content": "Pixelsynth [39] and Geometry-Free View Synthesis [40] address this challenge by optimizing the synthesizing model using multi-view supervision. However, their generalization to in-the-wild scenes is hindered by the lack of large-scale multi-view datasets. Single-view MPI [47] and MINE [26] decompose the scene into multiple layers and utilize an inpainting network to extend each occluded layer. Additionally, AdaMPI [13] addresses complex 3D scene structures through a novel plane adjustment network. These MPI-based methods have demonstrated success in synthesizing realistic images, and thus, we adopt multiplane images as our basic synthesis tool. However, to the best of our knowledge, there are currently no publicly available methods for generating optical flow datasets from MPI. To extract optical flows from MPI, we propose a novel pipeline that differs from previous MPI-based image synthesis methods by utilizing layered depths and virtual camera poses. Additionally, to enhance the realism of the generated optical flow dataset, we introduce an independent object motion module for static and dynamic decoupling, as well as a depth-aware inpainting module to remove unnatural occupations." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 657, + 189, + 671 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 657, + 189, + 671 + ], + "spans": [ + { + "bbox": [ + 47, + 657, + 189, + 671 + ], + "type": "text", + "content": "3. The Proposed MPI-Flow" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "content": "In this section, we first briefly review the basics of our motivation and formulation for novel view image generation. Then we introduce the optical flow generation" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 396, + 546, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 396, + 546, + 434 + ], + "spans": [ + { + "bbox": [ + 304, + 396, + 546, + 434 + ], + "type": "text", + "content": "pipeline. Next, we present the details of two crucial components of our approach, including independent object motions and depth-aware inpainting." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 442, + 463, + 453 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 442, + 463, + 453 + ], + "spans": [ + { + "bbox": [ + 305, + 442, + 463, + 453 + ], + "type": "text", + "content": "3.1. Motivation and Formulation" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "spans": [ + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "text", + "content": "Our goal is to generate a realistic novel view image " + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t\\in \\mathbb{R}^{H\\times W\\times 3}" + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "text", + "content": " and the corresponding optical flow maps " + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_{s\\rightarrow t}\\in \\mathbb{R}^{H\\times W\\times 2}" + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "text", + "content": " from single-view image " + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_s\\in \\mathbb{R}^{H\\times W\\times 3}" + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "inline_equation", + "content": "H" + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "inline_equation", + "content": "W" + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "text", + "content": " are the height and width of the image, respectively. The two-dimensional array on the optical flow " + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_{s\\rightarrow t}" + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "text", + "content": " represents the change of the corresponding pixel from image " + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_s" + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "text", + "content": " to image " + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t" + }, + { + "bbox": [ + 304, + 461, + 545, + 557 + ], + "type": "text", + "content": ". The input image, generated image, and optical flow together form a training pair." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 558, + 545, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 545, + 641 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 545, + 641 + ], + "type": "text", + "content": "To generate training pair, previous works [1, 12] wrap pixels from image " + }, + { + "bbox": [ + 304, + 558, + 545, + 641 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_s" + }, + { + "bbox": [ + 304, + 558, + 545, + 641 + ], + "type": "text", + "content": " to image " + }, + { + "bbox": [ + 304, + 558, + 545, + 641 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t" + }, + { + "bbox": [ + 304, + 558, + 545, + 641 + ], + "type": "text", + "content": " with estimated flows. This inevitably leads to holes and artifacts in the image " + }, + { + "bbox": [ + 304, + 558, + 545, + 641 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t" + }, + { + "bbox": [ + 304, + 558, + 545, + 641 + ], + "type": "text", + "content": ", which damages the image realism. Recent work [47, 26, 13] on Multiplane Images (MPI) reveals that the layered depth representation of the single-view image can significantly improve the realism of the generated novel view image." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 642, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 546, + 714 + ], + "type": "text", + "content": "We aim to tackle the image realism challenges in our methods and meanwhile enhance the optical flow realism and motion realism. Accordingly, we present an MPI-based optical flow dataset generation method, namely MPI-Flow. Figure 2 shows the MPI-Flow framework for training pair generation. To construct MPI, given the input image " + }, + { + "bbox": [ + 304, + 642, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_s" + }, + { + "bbox": [ + 304, + 642, + 546, + 714 + ], + "type": "text", + "content": "," + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "13859" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "type": "text", + "content": "an off-the-shelf monocular depth estimation network [38] is used to estimate its depth map. Then we use a neural network to construct " + }, + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "type": "text", + "content": " fronto-parallel RGB" + }, + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "type": "text", + "content": " planes with color, density, and depth predicted by neural networks in the rays under novel viewpoints." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 133, + 288, + 288 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 133, + 288, + 288 + ], + "spans": [ + { + "bbox": [ + 46, + 133, + 288, + 288 + ], + "type": "text", + "content": "To decouple dynamic objects, an instance segmentation network [7] gives the object mask. Then we use bilinear interpolation to obtain the object masks under two viewpoints respectively. Using object masks and constructed MPI, we use volume rendering to render the separate novel view images, optical flow maps, and depths of dynamic objects and the static scene, respectively. The optical flow " + }, + { + "bbox": [ + 46, + 133, + 288, + 288 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_{s\\rightarrow t}" + }, + { + "bbox": [ + 46, + 133, + 288, + 288 + ], + "type": "text", + "content": " can be obtained simply by adding the optical flows of the objects and the scene. However, due to different viewpoints, merging new images results in vacant areas and false occlusion. To this end, we design a depth-aware inpainting module, using rendered depths and object masks to fill the holes and repair false occlusion in the synthesized new image " + }, + { + "bbox": [ + 46, + 133, + 288, + 288 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 294, + 212, + 307 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 294, + 212, + 307 + ], + "spans": [ + { + "bbox": [ + 47, + 294, + 212, + 307 + ], + "type": "text", + "content": "3.2. Optical Flow Data Generation" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "spans": [ + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "content": "Novel View Image from MPI. To render realistic image " + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t" + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "content": " under a target viewpoint " + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "inline_equation", + "content": "\\pmb{\\mu}_t" + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "content": ", we use pixel warping from the source-view MPI in a differentiable manner. Specifically, we use a neural network " + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "content": " as in [13] to construct " + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "content": " frontoparallel RGB " + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "content": " planes under source viewpoint " + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "inline_equation", + "content": "\\pmb{\\mu}_s" + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "content": " with color channels " + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "inline_equation", + "content": "\\mathbf{c}_n" + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "content": ", density channel " + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "inline_equation", + "content": "\\sigma_n" + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "content": ", and depth " + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "inline_equation", + "content": "\\mathbf{d}_n" + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "content": " from the input image " + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_s" + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "content": " and its depth map " + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "inline_equation", + "content": "\\mathbf{D}_s" + }, + { + "bbox": [ + 46, + 312, + 287, + 396 + ], + "type": "text", + "content": " as:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 100, + 403, + 287, + 418 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 100, + 403, + 287, + 418 + ], + "spans": [ + { + "bbox": [ + 100, + 403, + 287, + 418 + ], + "type": "interline_equation", + "content": "\\left\\{\\left(\\mathbf {c} _ {n}, \\boldsymbol {\\sigma} _ {n}, \\mathbf {d} _ {n}\\right) \\right\\} _ {n = 1} ^ {N} = \\mathcal {F} \\left(\\mathbf {I} _ {s}, \\mathbf {D} _ {s}\\right), \\tag {1}", + "image_path": "a2e7121024c50d7bc2cd1bcbc9b99a46c557cebf0b053297295e6ae187e919a4.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 425, + 287, + 473 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 425, + 287, + 473 + ], + "spans": [ + { + "bbox": [ + 46, + 425, + 287, + 473 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 425, + 287, + 473 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 425, + 287, + 473 + ], + "type": "text", + "content": " is a predefined parameter that represents the number of planes in MPI. Each pixel " + }, + { + "bbox": [ + 46, + 425, + 287, + 473 + ], + "type": "inline_equation", + "content": "(x_{t},y_{t})" + }, + { + "bbox": [ + 46, + 425, + 287, + 473 + ], + "type": "text", + "content": " on the novel view image plane can be mapped to pixel " + }, + { + "bbox": [ + 46, + 425, + 287, + 473 + ], + "type": "inline_equation", + "content": "(x_{s},y_{s})" + }, + { + "bbox": [ + 46, + 425, + 287, + 473 + ], + "type": "text", + "content": " on " + }, + { + "bbox": [ + 46, + 425, + 287, + 473 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 46, + 425, + 287, + 473 + ], + "type": "text", + "content": "-th source MPI plane via homography function [15]:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 70, + 479, + 287, + 506 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 479, + 287, + 506 + ], + "spans": [ + { + "bbox": [ + 70, + 479, + 287, + 506 + ], + "type": "interline_equation", + "content": "\\left[ x _ {s}, y _ {s}, 1 \\right] ^ {T} \\sim \\mathbf {K} \\left(\\mathbf {R} - \\frac {\\mathbf {t n} ^ {T}}{\\mathbf {d} _ {n}}\\right) \\mathbf {K} ^ {- 1} \\left[ x _ {t}, y _ {t}, 1 \\right] ^ {T}, \\tag {2}", + "image_path": "846140485b18dd04b24b7930c26a5962afb5e23b6d55e86657865494bece6771.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "spans": [ + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "inline_equation", + "content": "\\mathbf{R}" + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "inline_equation", + "content": "\\mathbf{t}" + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "text", + "content": " are the rotation and translation from the source viewpoints " + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "inline_equation", + "content": "\\pmb{\\mu}_{s}" + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "text", + "content": " to the target viewpoints " + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "inline_equation", + "content": "\\pmb{\\mu}_{t}" + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "inline_equation", + "content": "\\mathbf{K}" + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "text", + "content": " is the camera intrinsic, and " + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "inline_equation", + "content": "\\mathbf{n} = [0,0,1]" + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "text", + "content": " is the normal vector. Thus, the color " + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "inline_equation", + "content": "\\mathbf{c}_n^\\prime" + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "text", + "content": " and density " + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "inline_equation", + "content": "\\sigma_{n}^{\\prime}" + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "text", + "content": " of each new plane for the novel view " + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t" + }, + { + "bbox": [ + 46, + 513, + 287, + 597 + ], + "type": "text", + "content": " can be obtained via bilinear sampling. We use discrete intersection points between new planes and arbitrary rays passing through the scene and estimate integrals:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 94, + 605, + 287, + 638 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 94, + 605, + 287, + 638 + ], + "spans": [ + { + "bbox": [ + 94, + 605, + 287, + 638 + ], + "type": "interline_equation", + "content": "\\mathbf {I} _ {t} = \\sum_ {n = 1} ^ {N} \\left(\\mathbf {c} _ {n} ^ {\\prime} \\boldsymbol {\\alpha} _ {n} ^ {\\prime} \\prod_ {m = 1} ^ {n - 1} \\left(1 - \\boldsymbol {\\alpha} _ {m} ^ {\\prime}\\right)\\right), \\tag {3}", + "image_path": "920604caef1429eaa28554844bea8bb805b74315bbdda09b0109b3e0ab2db5e0.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 641, + 287, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 287, + 677 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 287, + 677 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 641, + 287, + 677 + ], + "type": "inline_equation", + "content": "\\alpha_{n}^{\\prime} = \\exp \\left(-\\delta_{n}\\sigma_{n}^{\\prime}\\right)" + }, + { + "bbox": [ + 46, + 641, + 287, + 677 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 641, + 287, + 677 + ], + "type": "inline_equation", + "content": "\\delta_{n}" + }, + { + "bbox": [ + 46, + 641, + 287, + 677 + ], + "type": "text", + "content": " is the distance map between plane " + }, + { + "bbox": [ + 46, + 641, + 287, + 677 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 46, + 641, + 287, + 677 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 641, + 287, + 677 + ], + "type": "inline_equation", + "content": "n + 1" + }, + { + "bbox": [ + 46, + 641, + 287, + 677 + ], + "type": "text", + "content": " and we set the initial depth of MPI planes uniformly spaced in disparity as in [13]." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 689, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 689, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 689, + 287, + 714 + ], + "type": "text", + "content": "Optical Flow from MPI. Although MPI-based methods synthesize realistic images, reliable optical flow maps are" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": "also needed to train learning-based optical flow estimation models. Therefore, we propose adding an additional optical channel in each plane. To this end, we compute the optical flow on the " + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": "-th plane at pixel " + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "inline_equation", + "content": "[x_s, y_s]" + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": " of source image " + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_s" + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": " by " + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_n = [x_t - x_s, y_t - y_s]" + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": " with a backward-warp process in terms of the inverse equivalent form of Equation (2):" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 319, + 153, + 545, + 182 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 319, + 153, + 545, + 182 + ], + "spans": [ + { + "bbox": [ + 319, + 153, + 545, + 182 + ], + "type": "interline_equation", + "content": "\\left[ x _ {t}, y _ {t}, 1 \\right] ^ {T} \\sim \\mathbf {K} \\left(\\mathbf {R} ^ {\\dagger} - \\frac {\\mathbf {t} ^ {\\dagger} \\mathbf {n} ^ {T}}{\\mathbf {d} _ {n}}\\right) \\mathbf {K} ^ {- 1} \\left[ x _ {s}, y _ {s}, 1 \\right] ^ {T}, \\tag {4}", + "image_path": "68c8dc76c44b8c4b686463b5dceb11831904c60456ca35bfe7e04984118bf363.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "spans": [ + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "inline_equation", + "content": "x_{s}" + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "inline_equation", + "content": "y_{s}" + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "text", + "content": " are uniformly sampled from a " + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "inline_equation", + "content": "H\\times W" + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "text", + "content": " grid. " + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "inline_equation", + "content": "\\mathbf{R}^{\\dagger}" + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "inline_equation", + "content": "\\mathbf{t}^{\\dagger}" + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "text", + "content": " are the inverses of " + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "inline_equation", + "content": "\\mathbf{R}" + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "inline_equation", + "content": "\\mathbf{t}" + }, + { + "bbox": [ + 305, + 190, + 544, + 213 + ], + "type": "text", + "content": ", respectively." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 214, + 545, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 214, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 305, + 214, + 545, + 251 + ], + "type": "text", + "content": "To make sure that the optical flow maps match the novel view image " + }, + { + "bbox": [ + 305, + 214, + 545, + 251 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t" + }, + { + "bbox": [ + 305, + 214, + 545, + 251 + ], + "type": "text", + "content": " perfectly, we propose to render " + }, + { + "bbox": [ + 305, + 214, + 545, + 251 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_{s\\rightarrow t}" + }, + { + "bbox": [ + 305, + 214, + 545, + 251 + ], + "type": "text", + "content": " as in Equation (3) in terms of volume rendering:" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 346, + 260, + 545, + 293 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 346, + 260, + 545, + 293 + ], + "spans": [ + { + "bbox": [ + 346, + 260, + 545, + 293 + ], + "type": "interline_equation", + "content": "\\mathbf {F} _ {s \\rightarrow t} = \\sum_ {n = 1} ^ {N} \\left(\\mathbf {f} _ {n} \\boldsymbol {\\alpha} _ {n} \\prod_ {m = 1} ^ {n - 1} (1 - \\boldsymbol {\\alpha} _ {m})\\right), \\tag {5}", + "image_path": "5f3da54d189df50b49572bc1406018b1ae99399536fe1127111cd20aee4dcfd9.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 303, + 545, + 388 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 303, + 545, + 388 + ], + "spans": [ + { + "bbox": [ + 304, + 303, + 545, + 388 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 303, + 545, + 388 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_n\\in \\mathbb{R}^{H\\times W\\times 2}" + }, + { + "bbox": [ + 304, + 303, + 545, + 388 + ], + "type": "text", + "content": " is the optical flow maps on the " + }, + { + "bbox": [ + 304, + 303, + 545, + 388 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 304, + 303, + 545, + 388 + ], + "type": "text", + "content": " -th plane of image " + }, + { + "bbox": [ + 304, + 303, + 545, + 388 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_s" + }, + { + "bbox": [ + 304, + 303, + 545, + 388 + ], + "type": "text", + "content": ". The pipeline implemented thus far models the optical flows resulting from camera motion without considering the potential presence of independently dynamic objects. However, real-world scenes are highly likely to contain such objects. Not incorporating their motions can lead to domain gaps by unrealistic optical flows." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 401, + 545, + 461 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 401, + 545, + 461 + ], + "spans": [ + { + "bbox": [ + 304, + 401, + 545, + 461 + ], + "type": "text", + "content": "Independent Object Motions. To model more realistic motions, we propose applying separate virtual motions to objects and static backgrounds extracted from the scene. Therefore, we utilize an instance segmentation network " + }, + { + "bbox": [ + 304, + 401, + 545, + 461 + ], + "type": "inline_equation", + "content": "\\Omega" + }, + { + "bbox": [ + 304, + 401, + 545, + 461 + ], + "type": "text", + "content": " [7] for extracting the main object in the source image " + }, + { + "bbox": [ + 304, + 401, + 545, + 461 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_s" + }, + { + "bbox": [ + 304, + 401, + 545, + 461 + ], + "type": "text", + "content": " as:" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 376, + 472, + 545, + 487 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 376, + 472, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 376, + 472, + 545, + 487 + ], + "type": "interline_equation", + "content": "\\mathbf {M} _ {s} = \\Omega (\\mathbf {I} _ {s}) \\in \\mathbb {R} ^ {H \\times W}, \\tag {6}", + "image_path": "1d3095e36f3f70847b7f2e35abb25a2ac2e7e1099c46dff4c273a075b2c5aa91.jpg" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "spans": [ + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_s" + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": " is a binary mask to indicate the region of the object. To model the motions of the object " + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_s" + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": " in the scene, we construct separate viewpoints, including camera motion " + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\pmb{\\mu}_t^{sce}" + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": " and object motion " + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\pmb{\\mu}_t^{obj}" + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": ". We then obtain the rendered scene novel view " + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t^{sce}" + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": " and object novel view " + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t^{obj}" + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": " as in Equation (3). The separate optical flows, " + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_{s\\rightarrow t}^{sce}" + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_{s\\rightarrow t}^{obj}" + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": " can also be obtained as in Equation (5). The optical flows in " + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_{s\\rightarrow t}" + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": " are mixed by the values in " + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_{s\\rightarrow t}^{sce}" + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_{s\\rightarrow t}^{obj}" + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": " in terms of mask " + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_s" + }, + { + "bbox": [ + 304, + 494, + 545, + 616 + ], + "type": "text", + "content": " to get the final optical flow maps containing camera motion and dynamic objects for training." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "text", + "content": "We can then use the bilinear interpolation to get the new object masks " + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_t" + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_t^{obj}" + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "text", + "content": " under the new viewpoints " + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\pmb{\\mu}_t" + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\pmb{\\mu}_t^{obj}" + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "text", + "content": " via bilinear sampling from " + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_s" + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "text", + "content": ". Pixels in the new merged image are also selected according to the content masks " + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "inline_equation", + "content": "1 - \\mathbf{M}_t" + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_t^{obj}" + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t^{sce}" + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t^{obj}" + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "text", + "content": ". Then, a simple inpainting strategy [46] is used to fill the empty area in the new image with an inpainting mask calculated by " + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_{fill} = \\mathbf{M}_t\\odot (1 - \\mathbf{M}_t^{obj})" + }, + { + "bbox": [ + 304, + 616, + 545, + 714 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13860" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 133 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 133 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 133 + ], + "type": "text", + "content": "Depth-Aware Inpainting Although merged images give a realistic visual effect, depth changes caused by camera motion and object motion can also cause unnatural occlusions. To solve this problem, we use volume rendering to obtain the depth " + }, + { + "bbox": [ + 47, + 72, + 289, + 133 + ], + "type": "inline_equation", + "content": "\\mathbf{D}_t^{sce}" + }, + { + "bbox": [ + 47, + 72, + 289, + 133 + ], + "type": "text", + "content": " of the scene novel view:" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 91, + 140, + 287, + 174 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 140, + 287, + 174 + ], + "spans": [ + { + "bbox": [ + 91, + 140, + 287, + 174 + ], + "type": "interline_equation", + "content": "\\mathbf {D} _ {t} = \\sum_ {n = 1} ^ {N} \\left(\\mathbf {d} _ {n} ^ {\\prime} \\boldsymbol {\\alpha} _ {n} ^ {\\prime} \\prod_ {m = 1} ^ {n - 1} \\left(1 - \\boldsymbol {\\alpha} _ {m} ^ {\\prime}\\right)\\right), \\tag {7}", + "image_path": "1ce7f4fc4018027b8364e894a1c513aa78f131c420eb8312b5cb2d97b82d91ad.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 181, + 287, + 218 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 181, + 287, + 218 + ], + "spans": [ + { + "bbox": [ + 47, + 181, + 287, + 218 + ], + "type": "text", + "content": "and the depth of the object novel view " + }, + { + "bbox": [ + 47, + 181, + 287, + 218 + ], + "type": "inline_equation", + "content": "\\mathbf{D}_t^{obj}" + }, + { + "bbox": [ + 47, + 181, + 287, + 218 + ], + "type": "text", + "content": " can be obtained in the same way. We then utilize both depths to compute the occupation mask between the novel views:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 79, + 224, + 287, + 239 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 79, + 224, + 287, + 239 + ], + "spans": [ + { + "bbox": [ + 79, + 224, + 287, + 239 + ], + "type": "interline_equation", + "content": "\\mathbf {M} _ {o c c} = \\left(1 - \\mathbf {M} _ {t}\\right) \\odot \\mathbf {M} _ {t} ^ {o b j} \\odot \\left(\\mathbf {D} _ {t} < \\mathbf {D} _ {t} ^ {o b j}\\right), \\tag {8}", + "image_path": "eb11cbf37cb00bed6177cfa349e63fe59539264ccc03e1550ce04ced5a7b6288.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 247, + 287, + 282 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 247, + 287, + 282 + ], + "spans": [ + { + "bbox": [ + 47, + 247, + 287, + 282 + ], + "type": "text", + "content": "which indicates the background areas in front of the object. Therefore, we are able to restore the coincidence area between the object and the background in the new image " + }, + { + "bbox": [ + 47, + 247, + 287, + 282 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_t" + }, + { + "bbox": [ + 47, + 247, + 287, + 282 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 283, + 287, + 426 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 283, + 287, + 426 + ], + "spans": [ + { + "bbox": [ + 46, + 283, + 287, + 426 + ], + "type": "text", + "content": "Figure 3 provides a detailed illustration of the incremental effects of MPI-Flow with and without independent object motion and depth-aware inpainting. Novel view images and optical flows from single-view images can be generated with MPI-Flow and only camera motion, as shown in Figures 3(a) and 3(b). However, camera motion alone does not match the complex optical flows in real-world scenes. To address this issue, we introduce an independent object motion module, as shown in Figure 3(c), to ensure motion realism. To further enhance motion realism and address occlusion caused by object motion, we apply the depth-aware inpainting module, as shown in Figure 3(d)." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 436, + 128, + 449 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 436, + 128, + 449 + ], + "spans": [ + { + "bbox": [ + 47, + 436, + 128, + 449 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 456, + 110, + 467 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 456, + 110, + 467 + ], + "spans": [ + { + "bbox": [ + 47, + 456, + 110, + 467 + ], + "type": "text", + "content": "4.1. Datasets" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 474, + 287, + 557 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 474, + 287, + 557 + ], + "spans": [ + { + "bbox": [ + 46, + 474, + 287, + 557 + ], + "type": "text", + "content": "FlyingChairs [9] and FlyingThings3D [18] are both popular synthetic datasets that train optical flow models. As a standard practice, we use \"Ch\" and \"Th\" respectively to represent the two datasets, and \"Ch→Th\" means training first on \"Ch\" and fine-tuning on \"Th\". By default, we use the RAFT pre-trained on \"Ch→Th\" to be fine-tuned on the generated datasets and evaluated on labeled datasets." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 558, + 287, + 617 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 558, + 287, + 617 + ], + "spans": [ + { + "bbox": [ + 46, + 558, + 287, + 617 + ], + "type": "text", + "content": "COCO [27] is a collection of single still images and ground truth with labels for object detection or panoptic segmentation tasks. We sample 20k single-view still images from the train2017 split following Depthstillation [1] to generate virtual images and optical flow maps." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 617, + 287, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 287, + 676 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 287, + 676 + ], + "type": "text", + "content": "DAVIS [37] provides high-resolution videos and it is widely used for video object segmentation. We use all the 10581 images of the unsupervised 2019 challenge to generate datasets by MPI-Flow and other state-of-the-art optical flow dataset generation methods." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": "KITTI2012 [11] and KITTI2015 [34] are well-known benchmarks for optical flow estimation. There are multi-view extensions (4,000 for training and 3,989 for testing)" + } + ] + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 313, + 70, + 540, + 140 + ], + "blocks": [ + { + "bbox": [ + 313, + 70, + 540, + 140 + ], + "lines": [ + { + "bbox": [ + 313, + 70, + 540, + 140 + ], + "spans": [ + { + "bbox": [ + 313, + 70, + 540, + 140 + ], + "type": "image", + "image_path": "18aa294b4c43e2cfbbfb26d4f0b4339699614dabe1ce6839da29630733a0f5b5.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 313, + 156, + 539, + 191 + ], + "blocks": [ + { + "bbox": [ + 393, + 144, + 459, + 155 + ], + "lines": [ + { + "bbox": [ + 393, + 144, + 459, + 155 + ], + "spans": [ + { + "bbox": [ + 393, + 144, + 459, + 155 + ], + "type": "text", + "content": "(a) Source Image" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 313, + 156, + 539, + 191 + ], + "lines": [ + { + "bbox": [ + 313, + 156, + 539, + 191 + ], + "spans": [ + { + "bbox": [ + 313, + 156, + 539, + 191 + ], + "type": "image", + "image_path": "483db86c9c2fd68689ceb6a2e941c4a4d1f64516dc3c1df0c175456ee79e1724.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 313, + 206, + 539, + 242 + ], + "blocks": [ + { + "bbox": [ + 386, + 196, + 466, + 205 + ], + "lines": [ + { + "bbox": [ + 386, + 196, + 466, + 205 + ], + "spans": [ + { + "bbox": [ + 386, + 196, + 466, + 205 + ], + "type": "text", + "content": "(b) + Camera Motion" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 313, + 206, + 539, + 242 + ], + "lines": [ + { + "bbox": [ + 313, + 206, + 539, + 242 + ], + "spans": [ + { + "bbox": [ + 313, + 206, + 539, + 242 + ], + "type": "image", + "image_path": "4eefc23d3c4e9dc0b40e238ae4ab1584fdf26a5c403f7fefd2a52d53aeeed15c.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 313, + 258, + 539, + 293 + ], + "blocks": [ + { + "bbox": [ + 365, + 247, + 487, + 257 + ], + "lines": [ + { + "bbox": [ + 365, + 247, + 487, + 257 + ], + "spans": [ + { + "bbox": [ + 365, + 247, + 487, + 257 + ], + "type": "text", + "content": "(c) + Independent Object Motion" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 313, + 258, + 539, + 293 + ], + "lines": [ + { + "bbox": [ + 313, + 258, + 539, + 293 + ], + "spans": [ + { + "bbox": [ + 313, + 258, + 539, + 293 + ], + "type": "image", + "image_path": "1cb0d434562663e28645fa986f02ffedb6a994c4bd19a31bcee779da3164b59c.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 370, + 297, + 482, + 308 + ], + "lines": [ + { + "bbox": [ + 370, + 297, + 482, + 308 + ], + "spans": [ + { + "bbox": [ + 370, + 297, + 482, + 308 + ], + "type": "text", + "content": "(d) + Depth-Aware Inpainting" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 306, + 318, + 545, + 342 + ], + "lines": [ + { + "bbox": [ + 306, + 318, + 545, + 342 + ], + "spans": [ + { + "bbox": [ + 306, + 318, + 545, + 342 + ], + "type": "text", + "content": "Figure 3: Visualization of incrementally adding different modules to improve the realism of the generated data." + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_caption" + } + ], + "index": 18 + }, + { + "bbox": [ + 305, + 364, + 545, + 435 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 364, + 545, + 435 + ], + "spans": [ + { + "bbox": [ + 305, + 364, + 545, + 435 + ], + "type": "text", + "content": "datasets with no ground truth. We use the multi-view extension images (training and testing) of KITTI 2015 to generate datasets, separately. By default, we evaluate the trained models on KITTI 12 training set and KITTI 15 training set in the tables following [1] and [12], abbreviated as \"KITTI 15\" and \"KITTI 12\" in the following tables." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 305, + 436, + 545, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 436, + 545, + 495 + ], + "spans": [ + { + "bbox": [ + 305, + 436, + 545, + 495 + ], + "type": "text", + "content": "Sintel [5] is derived from the open-source 3D animated short film Sintel. The dataset has 23 different scenes. The stereo images are RGB, while the disparity is grayscale. Although not a real-world dataset, we use it to verify the model's generalization across domains." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 306, + 503, + 438, + 515 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 503, + 438, + 515 + ], + "spans": [ + { + "bbox": [ + 306, + 503, + 438, + 515 + ], + "type": "text", + "content": "4.2. Implementation Details" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 305, + 522, + 545, + 570 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 522, + 545, + 570 + ], + "spans": [ + { + "bbox": [ + 305, + 522, + 545, + 570 + ], + "type": "text", + "content": "Firstly, we provide a description of the learning-based optical flow estimation models that were utilized in our experiments. Subsequently, we outline the experimental parameters and setup along with the evaluation formulation." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "type": "text", + "content": "Optical Flow networks. To evaluate how effective our generated data are at training optical flow models, we select RAFT [45], which represents state-of-the-art architecture for supervised optical flow and has excellent generalization capability. By default, we train RAFT on generated data for 200K steps with a learning rate of " + }, + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "type": "inline_equation", + "content": "1 \\times 10^{-4}" + }, + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "type": "text", + "content": " and weight decay of " + }, + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "type": "inline_equation", + "content": "1 \\times 10^{-5}" + }, + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "type": "text", + "content": ", batch size of 6, and " + }, + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "type": "inline_equation", + "content": "288 \\times 960" + }, + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "type": "text", + "content": " image crops. This configuration is the default setting of RAFT fitting on KITTI with two GPUs but four times the number of training steps, following [12]. For the rest of the setup, we use the official implementation of RAFT without any modifications. All evaluations are performed on a single NVIDIA" + } + ] + } + ], + "index": 25 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13861" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 86, + 70, + 509, + 228 + ], + "blocks": [ + { + "bbox": [ + 86, + 70, + 509, + 228 + ], + "lines": [ + { + "bbox": [ + 86, + 70, + 509, + 228 + ], + "spans": [ + { + "bbox": [ + 86, + 70, + 509, + 228 + ], + "type": "table", + "html": "
Image SourceMethodSintel.CSintel.FKITTI 12KITTI 15
EPE ↓>3 ↓EPE ↓>3 ↓EPE ↓F1 ↓EPE ↓F1 ↓
COCODepthstillation [1]1.875.313.219.251.746.813.4513.08
RealFlow [12]N/AN/AN/AN/AN/AN/AN/AN/A
MPI-Flow (ours)1.874.593.168.291.364.913.4410.66
DAVISDepthstillation [1]2.707.523.8112.061.816.893.7913.22
RealFlow [12]1.734.813.478.711.596.083.5512.52
MPI-Flow (ours)1.794.773.068.561.415.363.3210.47
KITTI 15 TestDepthstillation [1]4.029.084.9613.231.775.973.9913.34
RealFlow [12]3.737.365.5311.311.275.162.438.86
MPI-Flow (ours)2.255.253.658.891.244.512.167.30
KITTI 15 TrainDepthstillation [1]2.847.184.3111.241.675.71{2.99}{9.94}
RealFlow [12]4.067.684.7811.441.255.02{2.17}{8.64}
MPI-Flow (ours)2.415.393.829.111.264.66{1.88}{7.16}
", + "image_path": "4d5f62940ac52ed2e7e8245dd1529ec551f9ba6b66a4a0e8d174dcc37d4cd6f6.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 317, + 160, + 329 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 317, + 160, + 329 + ], + "spans": [ + { + "bbox": [ + 47, + 317, + 160, + 329 + ], + "type": "text", + "content": "GeForce RTX 3090 GPU1." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "spans": [ + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "text", + "content": "Virtual Camera Motion. To generate the novel view images from COCO and DAVIS, we adopt the same settings in [1] to build the virtual camera. For KITTI, we empirically build the camera motion with three scalars where " + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "inline_equation", + "content": "t_x, t_y" + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "text", + "content": " are in " + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "inline_equation", + "content": "[-0.2, 0.2]" + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "inline_equation", + "content": "t_z" + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "text", + "content": " are in " + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "inline_equation", + "content": "[0.1, 0.35]" + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "text", + "content": ". We build the camera rotation with three Euler angles " + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "inline_equation", + "content": "a_x, a_y, a_z" + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "text", + "content": " in " + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "inline_equation", + "content": "[- \\frac{\\pi}{90}, \\frac{\\pi}{90}]" + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "text", + "content": ". We use single camera motion for each image from COCO but multiple camera motions (" + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "inline_equation", + "content": "\\times 4" + }, + { + "bbox": [ + 46, + 330, + 288, + 472 + ], + "type": "text", + "content": " by default) from DAVIS and KITTI as in [12], due to the small number of images and the homogeneity of the scene in video data. We show how the number of camera motions impacts the optical flow network performance in the discussion." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 473, + 287, + 534 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 473, + 287, + 534 + ], + "spans": [ + { + "bbox": [ + 46, + 473, + 287, + 534 + ], + "type": "text", + "content": "Evaluation Metrics. We report evaluation results on the average End-Point Error (EPE) and two error rates, respectively the percentage of pixels with an absolute error greater than " + }, + { + "bbox": [ + 46, + 473, + 287, + 534 + ], + "type": "inline_equation", + "content": "3 (> 3)" + }, + { + "bbox": [ + 46, + 473, + 287, + 534 + ], + "type": "text", + "content": " or both absolute and relative errors greater than 3 and " + }, + { + "bbox": [ + 46, + 473, + 287, + 534 + ], + "type": "inline_equation", + "content": "5\\%" + }, + { + "bbox": [ + 46, + 473, + 287, + 534 + ], + "type": "text", + "content": " respectively (Fl) on all pixels." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 540, + 270, + 553 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 540, + 270, + 553 + ], + "spans": [ + { + "bbox": [ + 47, + 540, + 270, + 553 + ], + "type": "text", + "content": "4.3. Comparison with State-of-the-art Methods" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 559, + 287, + 607 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 559, + 287, + 607 + ], + "spans": [ + { + "bbox": [ + 46, + 559, + 287, + 607 + ], + "type": "text", + "content": "In this section, we evaluate the effectiveness of the MPI-Flow generation pipeline on public benchmarks. We will highlight the best results in **bold** and **underline** the second-best if necessary among methods trained in fair conditions." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 607, + 287, + 667 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 607, + 287, + 667 + ], + "spans": [ + { + "bbox": [ + 46, + 607, + 287, + 667 + ], + "type": "text", + "content": "Comparison with Dataset Generation Methods. As a method for generating datasets from real-world images, we compare MPI-Flow with Depthstillation [1] and RealFlow [12], which are representative works in real-world dataset generation. In order to evaluate the effectiveness" + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 331, + 316, + 523, + 396 + ], + "blocks": [ + { + "bbox": [ + 46, + 236, + 547, + 298 + ], + "lines": [ + { + "bbox": [ + 46, + 236, + 547, + 298 + ], + "spans": [ + { + "bbox": [ + 46, + 236, + 547, + 298 + ], + "type": "text", + "content": "Table 1: The cross-dataset validation results and comparisons with other dataset generation methods from real images or videos are presented in this study. The \"Image Source\" column indicates the dataset used for optical flow training data generation. The evaluation results of RAFT trained on different datasets using different methods are reported. In cases where RealFlow fails to work on single-view images from COCO, the study indicates \"N/A\". The curly braces \"\\{\\}\" represent the use of the unlabeled evaluation set, which is the KITTI 15 training set in this table." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 331, + 316, + 523, + 396 + ], + "lines": [ + { + "bbox": [ + 331, + 316, + 523, + 396 + ], + "spans": [ + { + "bbox": [ + 331, + 316, + 523, + 396 + ], + "type": "table", + "html": "
DatasetKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
Ch→Th [18]2.088.865.0017.44
dDAVIS [1]1.816.893.7913.22
MF-DAVIS1.616.413.7712.40
dCOCO [1]1.806.663.8012.44
MF-COCO1.596.223.6811.95
", + "image_path": "84edfcf9c2076c005b02d44ffb962ccb6d873b37688659e73b1063e9bde53afd.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 403, + 545, + 441 + ], + "lines": [ + { + "bbox": [ + 305, + 403, + 545, + 441 + ], + "spans": [ + { + "bbox": [ + 305, + 403, + 545, + 441 + ], + "type": "text", + "content": "Table 2: Results on RAFT trained from scratch under the same setting. \"dX\" are from Depthstillation [1] while \"MF-X\" are from our proposed MPI-Flow" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 461, + 545, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 461, + 545, + 676 + ], + "spans": [ + { + "bbox": [ + 304, + 461, + 545, + 676 + ], + "type": "text", + "content": "of MPI-Flow, we follow the procedures of Depthstillation and RealFlow to construct training sets from four different datasets, including COCO, DAVIS, KITTI 15 multi-view train set, and KITTI 15 multi-view test set. To ensure fair comparisons, we conduct experiments with a similar number of training sets as our competitors. Specifically, for DAVIS and KITTI, we generate four motions for each image to match RealFlow, which trains RAFT for four EM iterations with four times the amount of data. For COCO, we follow the exact same setup as Depthstillation. Since Depthstillation does not provide details for KITTI 15 train, we use its default settings to obtain the results. Trained models are evaluated on the training sets of Sintel, KITTI 12, and KITTI 15. We report the evaluation results of models with the best performance in the paper for Depthstillation and RealFlow. Furthermore, we conduct cross-dataset experiments where RAFT is trained with one generated dataset and evaluated with another." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "content": "As shown in Table 1, even with the same amount of data, our approach gains significant improvements and generalization over multiple datasets. When trained and tested with" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 47, + 673, + 287, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 673, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 673, + 287, + 713 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 47, + 673, + 287, + 713 + ], + "type": "text", + "content": "RAFT with the same parameters loaded on different GPUs yield slightly different evaluation results. Therefore, to ensure fair comparison, we download the official model weights with the best performance provided by the compared methods and evaluate them on the same GPU." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13862" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 69, + 170, + 108 + ], + "blocks": [ + { + "bbox": [ + 49, + 69, + 170, + 108 + ], + "lines": [ + { + "bbox": [ + 49, + 69, + 170, + 108 + ], + "spans": [ + { + "bbox": [ + 49, + 69, + 170, + 108 + ], + "type": "image", + "image_path": "6c9872874dbce6f88dc9e94435216586fb035fe14830981d04e3325f26840b4f.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 49, + 112, + 169, + 150 + ], + "blocks": [ + { + "bbox": [ + 49, + 112, + 169, + 150 + ], + "lines": [ + { + "bbox": [ + 49, + 112, + 169, + 150 + ], + "spans": [ + { + "bbox": [ + 49, + 112, + 169, + 150 + ], + "type": "image", + "image_path": "0d0e458a409fe6f74c3a7be43be012010775bfa27f6a9e5f0c16f4c9bed619f3.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 76, + 155, + 141, + 166 + ], + "lines": [ + { + "bbox": [ + 76, + 155, + 141, + 166 + ], + "spans": [ + { + "bbox": [ + 76, + 155, + 141, + 166 + ], + "type": "text", + "content": "(a) Source Image" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 176, + 69, + 297, + 108 + ], + "blocks": [ + { + "bbox": [ + 176, + 69, + 297, + 108 + ], + "lines": [ + { + "bbox": [ + 176, + 69, + 297, + 108 + ], + "spans": [ + { + "bbox": [ + 176, + 69, + 297, + 108 + ], + "type": "image", + "image_path": "4a4f571291d256910cb7fdc5bcc3ac9761bf72e291cefb9b363bdd491dd55749.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 176, + 112, + 296, + 150 + ], + "blocks": [ + { + "bbox": [ + 176, + 112, + 296, + 150 + ], + "lines": [ + { + "bbox": [ + 176, + 112, + 296, + 150 + ], + "spans": [ + { + "bbox": [ + 176, + 112, + 296, + 150 + ], + "type": "image", + "image_path": "2263f6bc8e0fafe00c29c4a7545b33396f4f470f86c4198c3fc7583987ad8219.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 201, + 155, + 271, + 166 + ], + "lines": [ + { + "bbox": [ + 201, + 155, + 271, + 166 + ], + "spans": [ + { + "bbox": [ + 201, + 155, + 271, + 166 + ], + "type": "text", + "content": "(b) Depthstillation" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 304, + 69, + 424, + 108 + ], + "blocks": [ + { + "bbox": [ + 304, + 69, + 424, + 108 + ], + "lines": [ + { + "bbox": [ + 304, + 69, + 424, + 108 + ], + "spans": [ + { + "bbox": [ + 304, + 69, + 424, + 108 + ], + "type": "image", + "image_path": "90a4d2644a51927d4c2d271836f4bca126553384389c6e575226f3252fb3cfc7.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 304, + 112, + 423, + 150 + ], + "blocks": [ + { + "bbox": [ + 304, + 112, + 423, + 150 + ], + "lines": [ + { + "bbox": [ + 304, + 112, + 423, + 150 + ], + "spans": [ + { + "bbox": [ + 304, + 112, + 423, + 150 + ], + "type": "image", + "image_path": "37e6111293e159bdc603bdbcf8e064a98e848886eeb62eb16b86b68a313bafde.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 339, + 155, + 388, + 165 + ], + "lines": [ + { + "bbox": [ + 339, + 155, + 388, + 165 + ], + "spans": [ + { + "bbox": [ + 339, + 155, + 388, + 165 + ], + "type": "text", + "content": "(c) RealFlow" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 425, + 69, + 545, + 108 + ], + "blocks": [ + { + "bbox": [ + 425, + 69, + 545, + 108 + ], + "lines": [ + { + "bbox": [ + 425, + 69, + 545, + 108 + ], + "spans": [ + { + "bbox": [ + 425, + 69, + 545, + 108 + ], + "type": "image", + "image_path": "cdb122339af00be3468c779f56d2f6fc76330957cc409b378110940a9c6f6432.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 425, + 112, + 545, + 150 + ], + "blocks": [ + { + "bbox": [ + 425, + 112, + 545, + 150 + ], + "lines": [ + { + "bbox": [ + 425, + 112, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 425, + 112, + 545, + 150 + ], + "type": "image", + "image_path": "1d7f34f3b51b136a1c0e0fdcf33da02c40b9882f16a43b71dc527aa19e04c0c2.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 446, + 155, + 523, + 166 + ], + "lines": [ + { + "bbox": [ + 446, + 155, + 523, + 166 + ], + "spans": [ + { + "bbox": [ + 446, + 155, + 523, + 166 + ], + "type": "text", + "content": "(d) MPI-Flow (ours)" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 50, + 231, + 285, + 304 + ], + "blocks": [ + { + "bbox": [ + 46, + 175, + 547, + 212 + ], + "lines": [ + { + "bbox": [ + 46, + 175, + 547, + 212 + ], + "spans": [ + { + "bbox": [ + 46, + 175, + 547, + 212 + ], + "type": "text", + "content": "Figure 4: Qualitative results of generated images and optical flows from the KITTI 2015 training set. (a) contains the input source images. (b), (c), and (d) contain generated images of RealFlow [12], Depthstillation [1], and our proposed MPI-Flow. MPI-Flow eliminates the artifact in the new image and guarantees image realism. (Best viewed with zoom-in)" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 50, + 231, + 285, + 304 + ], + "lines": [ + { + "bbox": [ + 50, + 231, + 285, + 304 + ], + "spans": [ + { + "bbox": [ + 50, + 231, + 285, + 304 + ], + "type": "image", + "image_path": "da6707e7b80286d946ca8c549414289233de634768daf029b1f59ede4fe206b6.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 51, + 320, + 128, + 393 + ], + "blocks": [ + { + "bbox": [ + 106, + 308, + 228, + 319 + ], + "lines": [ + { + "bbox": [ + 106, + 308, + 228, + 319 + ], + "spans": [ + { + "bbox": [ + 106, + 308, + 228, + 319 + ], + "type": "text", + "content": "(a) Source Image from KITTI 15" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 51, + 320, + 128, + 393 + ], + "lines": [ + { + "bbox": [ + 51, + 320, + 128, + 393 + ], + "spans": [ + { + "bbox": [ + 51, + 320, + 128, + 393 + ], + "type": "image", + "image_path": "81e55a0103cf6eb67b950b31ad9a5cff5ded0d1f816cc7b41613195ae6690ffc.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 55, + 398, + 124, + 408 + ], + "lines": [ + { + "bbox": [ + 55, + 398, + 124, + 408 + ], + "spans": [ + { + "bbox": [ + 55, + 398, + 124, + 408 + ], + "type": "text", + "content": "(b) Depthstillation" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 129, + 320, + 206, + 392 + ], + "blocks": [ + { + "bbox": [ + 129, + 320, + 206, + 392 + ], + "lines": [ + { + "bbox": [ + 129, + 320, + 206, + 392 + ], + "spans": [ + { + "bbox": [ + 129, + 320, + 206, + 392 + ], + "type": "image", + "image_path": "3e09a57c2ded5c79c814a00c1d54c4c332a422696f67ae6ee0144ab751beb139.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 143, + 398, + 192, + 408 + ], + "lines": [ + { + "bbox": [ + 143, + 398, + 192, + 408 + ], + "spans": [ + { + "bbox": [ + 143, + 398, + 192, + 408 + ], + "type": "text", + "content": "(c) RealFlow" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_caption" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 207, + 320, + 284, + 393 + ], + "blocks": [ + { + "bbox": [ + 207, + 320, + 284, + 393 + ], + "lines": [ + { + "bbox": [ + 207, + 320, + 284, + 393 + ], + "spans": [ + { + "bbox": [ + 207, + 320, + 284, + 393 + ], + "type": "image", + "image_path": "7831bbf1fc3879e5e55f8195f3f4a80f7a08b71d41b6902bed7c2b671f65460c.jpg" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 207, + 398, + 283, + 408 + ], + "lines": [ + { + "bbox": [ + 207, + 398, + 283, + 408 + ], + "spans": [ + { + "bbox": [ + 207, + 398, + 283, + 408 + ], + "type": "text", + "content": "(d) MPI-Flow (ours)" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_caption" + } + ], + "index": 19 + }, + { + "type": "image", + "bbox": [ + 48, + 481, + 159, + 555 + ], + "blocks": [ + { + "bbox": [ + 46, + 418, + 287, + 467 + ], + "lines": [ + { + "bbox": [ + 46, + 418, + 287, + 467 + ], + "spans": [ + { + "bbox": [ + 46, + 418, + 287, + 467 + ], + "type": "text", + "content": "Figure 5: Visualization of generated images with Depthstillation, RealFlow, and our proposed MPI-Flow from KITTI. Note that RealFlow generates such data using two frames with estimated optical flow." + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 48, + 481, + 159, + 555 + ], + "lines": [ + { + "bbox": [ + 48, + 481, + 159, + 555 + ], + "spans": [ + { + "bbox": [ + 48, + 481, + 159, + 555 + ], + "type": "image", + "image_path": "1caead2e32017dd6cf68a96d50cc32de4eb68d37e269d309d72705545bfab18c.jpg" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 69, + 560, + 138, + 571 + ], + "lines": [ + { + "bbox": [ + 69, + 560, + 138, + 571 + ], + "spans": [ + { + "bbox": [ + 69, + 560, + 138, + 571 + ], + "type": "text", + "content": "(a) Depthstillation" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 581, + 287, + 605 + ], + "lines": [ + { + "bbox": [ + 46, + 581, + 287, + 605 + ], + "spans": [ + { + "bbox": [ + 46, + 581, + 287, + 605 + ], + "type": "text", + "content": "Figure 6: Visualization of generated images with Depthstillation and our proposed MPI-Flow using a single view." + } + ] + } + ], + "index": 26, + "angle": 0, + "type": "image_caption" + } + ], + "index": 22 + }, + { + "type": "image", + "bbox": [ + 176, + 481, + 286, + 555 + ], + "blocks": [ + { + "bbox": [ + 176, + 481, + 286, + 555 + ], + "lines": [ + { + "bbox": [ + 176, + 481, + 286, + 555 + ], + "spans": [ + { + "bbox": [ + 176, + 481, + 286, + 555 + ], + "type": "image", + "image_path": "0ec822264feb48785c74b26e0f1943736703b95cef9bf3c648bb0635ccc43d8f.jpg" + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 192, + 560, + 269, + 571 + ], + "lines": [ + { + "bbox": [ + 192, + 560, + 269, + 571 + ], + "spans": [ + { + "bbox": [ + 192, + 560, + 269, + 571 + ], + "type": "text", + "content": "(b) MPI-Flow (ours)" + } + ] + } + ], + "index": 25, + "angle": 0, + "type": "image_caption" + } + ], + "index": 24 + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "content": "the same KITTI 15 Train image source, our EPE outperforms the second-best by a remarkable 0.29. When trained and tested with different image sources, our MPI-Flow demonstrates clear improvements over the competitors on almost all the evaluation settings. Notably, MPI-Flow achieves much better performance, even though RealFlow requires two consecutive frames to generate datasets, while" + } + ] + } + ], + "index": 27 + }, + { + "type": "table", + "bbox": [ + 309, + 231, + 543, + 365 + ], + "blocks": [ + { + "bbox": [ + 309, + 231, + 543, + 365 + ], + "lines": [ + { + "bbox": [ + 309, + 231, + 543, + 365 + ], + "spans": [ + { + "bbox": [ + 309, + 231, + 543, + 365 + ], + "type": "table", + "html": "
MethodKITTI 12KITTI 15
EPE ↓Fl ↓EPE ↓Fl ↓
SemiFlowGAN [25]--{16.02}{38.77}
FlowSupervisor [20]--{3.35}{11.12}
DistractFlow [21]--{3.01}{11.7}
Meta-Learning [36]--{2.81}-
SimFlow [19]--{5.19}-
ARFlow [28]1.44-{2.85}-
UFlow [22]1.68-2.719.05
UpFlow [33]1.27-2.45-
SMURF [42]--{2.00}{6.42}
MPI-Flow1.184.46{1.80}{6.63}
", + "image_path": "dd79828c59fb4a7b2a3f124379025a208f4cd58f372ddf1cbe40f579bd8b04b6.jpg" + } + ] + } + ], + "index": 28, + "angle": 0, + "type": "table_body" + } + ], + "index": 28 + }, + { + "bbox": [ + 306, + 374, + 545, + 398 + ], + "lines": [ + { + "bbox": [ + 306, + 374, + 545, + 398 + ], + "spans": [ + { + "bbox": [ + 306, + 374, + 545, + 398 + ], + "type": "text", + "content": "Table 3: Comparison with semi-supervised and unsupervised methods. " + }, + { + "bbox": [ + 306, + 374, + 545, + 398 + ], + "type": "inline_equation", + "content": "\\cdot -" + }, + { + "bbox": [ + 306, + 374, + 545, + 398 + ], + "type": "text", + "content": " ’ indicates no results reported." + } + ] + } + ], + "index": 29, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 423, + 459, + 435 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 423, + 459, + 435 + ], + "spans": [ + { + "bbox": [ + 306, + 423, + 459, + 435 + ], + "type": "text", + "content": "MPI-Flow needs only one still image." + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 304, + 437, + 545, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 437, + 545, + 616 + ], + "spans": [ + { + "bbox": [ + 304, + 437, + 545, + 616 + ], + "type": "text", + "content": "It is worth comparing MPI-Flow with Depthstillation under the same settings to evaluate their performance. For this comparison, we use the exact same settings as Depthstillation. Specifically, we generate MPI-Flow datasets with 1) no object motion, 2) the same camera parameters, 3) one camera motion per image, and 4) without pre-training on " + }, + { + "bbox": [ + 304, + 437, + 545, + 616 + ], + "type": "inline_equation", + "content": "\\mathrm{Ch}\\rightarrow \\mathrm{Th}" + }, + { + "bbox": [ + 304, + 437, + 545, + 616 + ], + "type": "text", + "content": ". The datasets generated are named MF-DAVIS and MF-COCO, while dCOCO and dDAVIS are generated from Depthstillation. The models are trained from scratch with the respective datasets. RealFlow is not included in this table as it requires a pre-trained optical flow model to generate datasets. The evaluation results are shown in Table 2. Our method outperforms Depthstillation with significant improvements on both COCO and DAVIS, demonstrating the importance of image realism." + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": "Comparison with Unsupervised Methods. Another way to utilize real-world data is through unsupervised learning, which learns optical flow pixels directly without the need for optical flow labels. In order to further demonstrate the effectiveness of MPI-Flow, we compare our method with the existing literature on unsupervised methods. The results of this comparison can be seen in Table 3. All methods are evaluated under the condition that only images from" + } + ] + } + ], + "index": 32 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13863" + } + ] + } + ], + "index": 33 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 85, + 70, + 509, + 139 + ], + "blocks": [ + { + "bbox": [ + 85, + 70, + 509, + 139 + ], + "lines": [ + { + "bbox": [ + 85, + 70, + 509, + 139 + ], + "spans": [ + { + "bbox": [ + 85, + 70, + 509, + 139 + ], + "type": "table", + "html": "
Dynamic ObjectsDepth-Aware InpaintingMultiple ObjectsSintel.CSintel.FKITTI 12KITTI 15
EPE ↓>3 ↓EPE ↓>3 ↓EPE ↓Fl ↓EPE ↓Fl ↓
XXX2.586.104.049.671.204.34{2.46}{8.38}
✓XX2.415.393.829.111.264.66{1.88}{7.16}
✓✓X2.375.443.719.051.254.58{1.91}{7.06}
✓✓✓2.205.353.679.031.234.46{1.92}{7.05}
", + "image_path": "c7de020e239a8f1a905f622f4c2d8e086680002b141b2e67a5c3a5cb18b53cfc.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 58, + 190, + 278, + 304 + ], + "blocks": [ + { + "bbox": [ + 46, + 148, + 547, + 172 + ], + "lines": [ + { + "bbox": [ + 46, + 148, + 547, + 172 + ], + "spans": [ + { + "bbox": [ + 46, + 148, + 547, + 172 + ], + "type": "text", + "content": "Table 4: Ablation experiments. Settings used are marked with a checkmark. Here we only perform four camera motions per image for these experiments due to the limitation of computational resources." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 58, + 190, + 278, + 304 + ], + "lines": [ + { + "bbox": [ + 58, + 190, + 278, + 304 + ], + "spans": [ + { + "bbox": [ + 58, + 190, + 278, + 304 + ], + "type": "table", + "html": "
MethodKITTI 15KITTI 15 test
EPE ↓Fl ↓Fl ↓
PWC-Net [44]{2.16}{9.80}9.60
LiteFlowNet [16]{1.62}{5.58}9.38
IRR-PWC [17]{1.63}{5.32}7.65
RAFT [45]{0.63}{1.50}5.10
Depthstillation [12]---
AutoFlow [43]--4.78
RealFlow [12]{0.58}{1.35}4.63
MPI-Flow{0.58}{1.30}4.58
", + "image_path": "97e88b8580bb192ba47e6b5d2600a7706177521eee13e4f39a36c501ce8c15dd.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 359, + 287, + 467 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 359, + 287, + 467 + ], + "spans": [ + { + "bbox": [ + 46, + 359, + 287, + 467 + ], + "type": "text", + "content": "the evaluation set could be used, without access to ground truth labels. For evaluation, we train the RAFT on our generated dataset with images from the KITTI 15 training set. Our MPI-Flow outperform all unsupervised methods in terms of EPE on both the KITTI 12 training set and KITTI 15 training set, with no need for any unsupervised constraints. However, our method performs better on EPE but has slightly lower F1 than SMURF, mainly because SMURF employs multiple frames for training." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 468, + 287, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 468, + 287, + 552 + ], + "spans": [ + { + "bbox": [ + 46, + 468, + 287, + 552 + ], + "type": "text", + "content": "Comparison with Supervised Methods. To further prove the effectiveness of MPI-Flow, we use KITTI 15 train set to fine-tune RAFT pre-trained by our generated dataset with images from KITTI 15 test set. The evaluation results on KITTI 15 train and KITTI 15 test are shown in Table 5. We achieve state-of-art performance on KITTI 2015 test benchmark compared to supervised methods on training RAFT." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 552, + 287, + 649 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 552, + 287, + 649 + ], + "spans": [ + { + "bbox": [ + 46, + 552, + 287, + 649 + ], + "type": "text", + "content": "Qualitative Results. Figure 4 show the generated images from the methods utilizing real-world images, as presented in Table 1. In this comparison, we use images from the KITTI 15 dataset as source image input. The images generated by RealFlow [12] and Depthstillation [1] with artifacts degrade the image realism. In contrast, MPI-Flow generates more realistic images than the other two methods. More results are shown in Figures 5 and 6." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 658, + 119, + 670 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 658, + 119, + 670 + ], + "spans": [ + { + "bbox": [ + 47, + 658, + 119, + 670 + ], + "type": "text", + "content": "4.4. Discussion" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": "To verify the effectiveness of the proposed MPI-Flow, we discuss the performance of models trained with generated datasets with different settings. We show more discus" + } + ] + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 338, + 190, + 515, + 270 + ], + "blocks": [ + { + "bbox": [ + 47, + 312, + 288, + 335 + ], + "lines": [ + { + "bbox": [ + 47, + 312, + 288, + 335 + ], + "spans": [ + { + "bbox": [ + 47, + 312, + 288, + 335 + ], + "type": "text", + "content": "Table 5: Comparison with supervised methods fine-tuned or trained on KITTI 15 train set." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 338, + 190, + 515, + 270 + ], + "lines": [ + { + "bbox": [ + 338, + 190, + 515, + 270 + ], + "spans": [ + { + "bbox": [ + 338, + 190, + 515, + 270 + ], + "type": "table", + "html": "
Motions \nPer ImageKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
11.294.582.027.35
41.234.461.927.05
101.214.491.827.02
201.204.411.796.86
401.184.461.806.63
", + "image_path": "13fd65aa5a0dbc28b04bf071e76da5e2b253653d9d1fef687bbcacaf9b4b0e1e.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "type": "table", + "bbox": [ + 338, + 318, + 515, + 376 + ], + "blocks": [ + { + "bbox": [ + 306, + 279, + 545, + 304 + ], + "lines": [ + { + "bbox": [ + 306, + 279, + 545, + 304 + ], + "spans": [ + { + "bbox": [ + 306, + 279, + 545, + 304 + ], + "type": "text", + "content": "Table 6: Effect of amount of virtual camera motions (training pairs) per source image." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 338, + 318, + 515, + 376 + ], + "lines": [ + { + "bbox": [ + 338, + 318, + 515, + 376 + ], + "spans": [ + { + "bbox": [ + 338, + 318, + 515, + 376 + ], + "type": "table", + "html": "
Objects \nPer ImageKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
11.254.581.917.06
21.264.762.027.19
41.234.461.927.05
", + "image_path": "3065d864d59b1bdf0793125027055e2a0c5c857a89a1c50844d89343cc2f18fc.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 311, + 385, + 539, + 397 + ], + "lines": [ + { + "bbox": [ + 311, + 385, + 539, + 397 + ], + "spans": [ + { + "bbox": [ + 311, + 385, + 539, + 397 + ], + "type": "text", + "content": "Table 7: Effect of amount of dynamic objects per image." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 305, + 422, + 538, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 422, + 538, + 434 + ], + "spans": [ + { + "bbox": [ + 305, + 422, + 538, + 434 + ], + "type": "text", + "content": "sion and evaluation results in the supplementary material." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 436, + 545, + 699 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 436, + 545, + 699 + ], + "spans": [ + { + "bbox": [ + 304, + 436, + 545, + 699 + ], + "type": "text", + "content": "Object Motion and Depth-Aware Inpainting. We conduct a series of ablation studies to analyze the impact of different choices in our proposed MPI-Flow for new image synthesis, including object motion, depth-aware inpainting, and multiple objects. \"Multiple objects\" indicates multiple moving objects in each image. To measure the impact of these factors, we generate new images from the KITTI 15 training set to train RAFT and evaluate them on the KITTI 12 training set and KITTI 15 training set. Because there are multiple combinations of these factors, we test by incrementally adding components of our approach, as shown in Table 4. In the first row, we show the performance achieved by generating new images without dynamic objects, thus assuming that optical flow comes from camera motion only. Then we incrementally add single-object motion, depth-aware inpainting, and multi-object motion to model a more realistic scenario. There are considerable improvements in almost all datasets on various metrics, except for the KITTI 12 training set, possibly due to the infrequent dynamic object motion in this dataset. The EPE on KITTI 15 remains relatively stable within the normal margin after adding the depth-aware inpainting module and the multi-object trick." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 701, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 701, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 306, + 701, + 545, + 712 + ], + "type": "text", + "content": "Camera Motion Parameters. We also conduct a series of" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13864" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 70, + 70, + 265, + 140 + ], + "blocks": [ + { + "bbox": [ + 70, + 70, + 265, + 140 + ], + "lines": [ + { + "bbox": [ + 70, + 70, + 265, + 140 + ], + "spans": [ + { + "bbox": [ + 70, + 70, + 265, + 140 + ], + "type": "table", + "html": "
tzKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
0.1 ~ 0.451.254.60{1.79}{6.68}
0.1 ~ 0.351.184.46{1.80}{6.63}
0.1 ~ 0.251.194.50{1.86}{6.71}
0.0 ~ 0.351.124.32{1.94}{6.92}
", + "image_path": "0e04051af9c4f0b1bcf9182430721e7addeff6ffedff803e64813f387f7733e3.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 69, + 172, + 266, + 232 + ], + "blocks": [ + { + "bbox": [ + 85, + 148, + 248, + 160 + ], + "lines": [ + { + "bbox": [ + 85, + 148, + 248, + 160 + ], + "spans": [ + { + "bbox": [ + 85, + 148, + 248, + 160 + ], + "type": "text", + "content": "Table 8: Effect of motion parameters " + }, + { + "bbox": [ + 85, + 148, + 248, + 160 + ], + "type": "inline_equation", + "content": "{t}_{z}" + }, + { + "bbox": [ + 85, + 148, + 248, + 160 + ], + "type": "text", + "content": " ." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 69, + 172, + 266, + 232 + ], + "lines": [ + { + "bbox": [ + 69, + 172, + 266, + 232 + ], + "spans": [ + { + "bbox": [ + 69, + 172, + 266, + 232 + ], + "type": "table", + "html": "
txandtyKITTI 12KITTI 15
EPE ↓Fl ↓EPE ↓Fl ↓
-0.3 ~ 0.31.224.42{1.92}{6.83}
-0.2 ~ 0.21.184.46{1.80}{6.63}
-0.1 ~ 0.11.324.99{1.98}{7.02}
", + "image_path": "63ec7c69827ebbf08456e84b2e4edc9156800a1599776c24549b0ad661e3ee3f.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 69, + 264, + 266, + 345 + ], + "blocks": [ + { + "bbox": [ + 70, + 239, + 262, + 252 + ], + "lines": [ + { + "bbox": [ + 70, + 239, + 262, + 252 + ], + "spans": [ + { + "bbox": [ + 70, + 239, + 262, + 252 + ], + "type": "text", + "content": "Table 9: Effect of motion parameters " + }, + { + "bbox": [ + 70, + 239, + 262, + 252 + ], + "type": "inline_equation", + "content": "{t}_{x}" + }, + { + "bbox": [ + 70, + 239, + 262, + 252 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 70, + 239, + 262, + 252 + ], + "type": "inline_equation", + "content": "{t}_{y}" + }, + { + "bbox": [ + 70, + 239, + 262, + 252 + ], + "type": "text", + "content": " ." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 69, + 264, + 266, + 345 + ], + "lines": [ + { + "bbox": [ + 69, + 264, + 266, + 345 + ], + "spans": [ + { + "bbox": [ + 69, + 264, + 266, + 345 + ], + "type": "table", + "html": "
DatasetKITTI 12KITTI 15
EPE ↓Fl ↓EPE ↓Fl ↓
Ch→Th [18]4.1421.3810.3533.67
dDAVIS [1]2.8111.296.8821.87
MF-DAVIS2.7011.256.9220.97
dCOCO [1]3.1613.308.4926.06
MF-COCO3.0211.208.2223.40
", + "image_path": "cb53a2e0721cf75e78ee1354186e4f7afa520d92494189c31fee3ffc96553aa3.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 400, + 286, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 400, + 286, + 544 + ], + "spans": [ + { + "bbox": [ + 46, + 400, + 286, + 544 + ], + "type": "text", + "content": "ablation studies to analyze the impact of different parameters on camera motions. We first show the effect of " + }, + { + "bbox": [ + 46, + 400, + 286, + 544 + ], + "type": "inline_equation", + "content": "t_z" + }, + { + "bbox": [ + 46, + 400, + 286, + 544 + ], + "type": "text", + "content": ", which indicates the range of moving forward and backward distances, as shown in Table 4. We set the minimum " + }, + { + "bbox": [ + 46, + 400, + 286, + 544 + ], + "type": "inline_equation", + "content": "t_z" + }, + { + "bbox": [ + 46, + 400, + 286, + 544 + ], + "type": "text", + "content": " to 0.1 by default, considering that most cameras on vehicles only move forward in the KITTI dataset. We also show the effect of " + }, + { + "bbox": [ + 46, + 400, + 286, + 544 + ], + "type": "inline_equation", + "content": "t_x" + }, + { + "bbox": [ + 46, + 400, + 286, + 544 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 400, + 286, + 544 + ], + "type": "inline_equation", + "content": "t_y" + }, + { + "bbox": [ + 46, + 400, + 286, + 544 + ], + "type": "text", + "content": ", representing the distance from left to right and from up to down, respectively. Because there are multiple combinations of parameters, we only test a specific parameter of our method in isolation. Settings used by default are underlined. The results show that a more reasonable range of camera motion leads to better performance." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 544, + 286, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 544, + 286, + 628 + ], + "spans": [ + { + "bbox": [ + 46, + 544, + 286, + 628 + ], + "type": "text", + "content": "Model Architectures The default model used in our paper is RFAT [45]. Table 10 shows that our proposed MPI-Flow also works for PWC-Net [44] compared with depthstillation [1] in a fair setting. We generate data from COCO and DAVIS and train PWC-Net, in which the results are still better than PWC-Net trained on " + }, + { + "bbox": [ + 46, + 544, + 286, + 628 + ], + "type": "inline_equation", + "content": "\\mathrm{Ch} \\rightarrow \\mathrm{Th}" + }, + { + "bbox": [ + 46, + 544, + 286, + 628 + ], + "type": "text", + "content": " or datasets generated from depthstillation." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "type": "text", + "content": "Amount of Virtual Motions. We can generate multiple camera motions with multiple dynamic objects for any given single image and thus a variety of paired images and ground-truth optical flow maps. Thus we can increase the number of camera motions to generate more data. Table 6 shows the impact of different amounts of camera motions on model performance. Interestingly, MPI-Flow with 4 mo" + } + ] + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 309, + 70, + 544, + 129 + ], + "blocks": [ + { + "bbox": [ + 46, + 354, + 287, + 377 + ], + "lines": [ + { + "bbox": [ + 46, + 354, + 287, + 377 + ], + "spans": [ + { + "bbox": [ + 46, + 354, + 287, + 377 + ], + "type": "text", + "content": "Table 10: Results on PWC-Net trained on generated datasets from scratch under the same setting." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 309, + 70, + 544, + 129 + ], + "lines": [ + { + "bbox": [ + 309, + 70, + 544, + 129 + ], + "spans": [ + { + "bbox": [ + 309, + 70, + 544, + 129 + ], + "type": "table", + "html": "
DatasetQuantityKITTI 12KITTI 15
EPE ↓F1 ↓EPE ↓F1 ↓
Ch→Th [18]47K2.088.865.0017.44
MF-COCO20K1.596.223.6811.95
MF-COCO120K1.515.943.4111.16
", + "image_path": "394650d0014f127dd0cb922a5c93d298c0518fd07fb51481ea8c9bc79fbe667a.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 333, + 137, + 516, + 148 + ], + "lines": [ + { + "bbox": [ + 333, + 137, + 516, + 148 + ], + "spans": [ + { + "bbox": [ + 333, + 137, + 516, + 148 + ], + "type": "text", + "content": "Table 11: Effect of amount of source images." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 172, + 545, + 327 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 172, + 545, + 327 + ], + "spans": [ + { + "bbox": [ + 304, + 172, + 545, + 327 + ], + "type": "text", + "content": "tions per image already allows for strong generalization to real domains, outperforming the results achieved using synthetic datasets shown in the previous evaluation results. Increasing the motions per image by factors 10 and 20 both lead to better performance on KITTI 12 and KITTI 15 compared to 4 and 1. Using 40 motions per image gives the best performance on KITTI 15 in terms of Fl. It indicates that a more variegate image content in the generated dataset may be beneficial for generalization to real applications. Table 7 shows the effect of amounts of dynamic objects on model performance. Increasing the number of dynamic objects improves the performance of the model on KITTI 12 but slightly decreases it on KITTI 15 in terms of EPE." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 328, + 545, + 412 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 328, + 545, + 412 + ], + "spans": [ + { + "bbox": [ + 304, + 328, + 545, + 412 + ], + "type": "text", + "content": "Quantity of Source Images The number of source images affects the scene diversity of the generated dataset. Empirically, more source images will be more conducive to model learning, as verified in Table 11. We verify the effect of the number of source images on the MF-COCO. The model performance is significantly improved by increasing the number of source images." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 426, + 378, + 438 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 426, + 378, + 438 + ], + "spans": [ + { + "bbox": [ + 306, + 426, + 378, + 438 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 447, + 545, + 637 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 447, + 545, + 637 + ], + "spans": [ + { + "bbox": [ + 304, + 447, + 545, + 637 + ], + "type": "text", + "content": "In this paper, we present a new framework for generating optical flow datasets, which addresses two main challenges: image realism and motion realism. Firstly, we propose an MPI-based image rendering pipeline that generates realistic images with corresponding optical flows from novel viewpoints. This pipeline utilizes volume rendering to address image artifacts and holes, leading to more realistic images. Secondly, we introduce an independent object motion module that separates dynamic objects from the static scene. By decoupling object motion, we further improve motion realism. Additionally, we design a depth-aware inpainting module that handles unnatural occlusions caused by object motion in the generated images. Through these novel designs, our approach achieves superior performance on real-world datasets compared to both unsupervised and supervised methods for training learning-based models." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 641, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 545, + 712 + ], + "type": "text", + "content": "Acknowledgments This work was supported by the National Natural Science Foundation of China (12202048, 62171038, and 62171042), the R&D Program of Beijing Municipal Education Commission (KZ202211417048), and the Fundamental Research Funds for the Central Universities." + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13865" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "type": "text", + "content": "[1] Filippo Aleotti, Matteo Poggi, and Stefano Mattoccia. Learning optical flow from still images. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 15201-15211, 2021. 1, 2, 3, 5, 6, 7, 8, 9" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 136, + 288, + 179 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 136, + 288, + 179 + ], + "spans": [ + { + "bbox": [ + 53, + 136, + 288, + 179 + ], + "type": "text", + "content": "[2] Simon Baker, Daniel Scharstein, JP Lewis, Stefan Roth, Michael J Black, and Richard Szeliski. A database and evaluation methodology for optical flow. International Journal of Computer Vision (IJCV), 92(1):1-31, 2011. 1, 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 180, + 287, + 223 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 180, + 287, + 223 + ], + "spans": [ + { + "bbox": [ + 53, + 180, + 287, + 223 + ], + "type": "text", + "content": "[3] Thomas Brox, Christoph Bregler, and Jitendra Malik. Large displacement optical flow. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 41-48, 2009. 1" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 224, + 287, + 269 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 224, + 287, + 269 + ], + "spans": [ + { + "bbox": [ + 53, + 224, + 287, + 269 + ], + "type": "text", + "content": "[4] D. J. Butler, J. Wulff, G. B. Stanley, and M. J. Black. A naturalistic open source movie for optical flow evaluation. In the European Conference on Computer Vision (ECCV), pages 611-625, 2012. 1" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 270, + 287, + 313 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 270, + 287, + 313 + ], + "spans": [ + { + "bbox": [ + 53, + 270, + 287, + 313 + ], + "type": "text", + "content": "[5] Daniel J Butler, Jonas Wulff, Garrett B Stanley, and Michael J Black. A naturalistic open source movie for optical flow evaluation. In the European Conference on Computer Vision (ECCV), pages 611-625, 2012. 5" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 315, + 287, + 369 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 315, + 287, + 369 + ], + "spans": [ + { + "bbox": [ + 53, + 315, + 287, + 369 + ], + "type": "text", + "content": "[6] Gustavo Sutter P. Carvalho, Diogo Carbonera Luvizon, Antonio Joia Neto, Andre G. C. Pacheco, and Otavio Augusto Bizetto Penatti. Learning multiplane images from single views with self-supervision. In British Machine Vision Conference (BMVC), 2021. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 369, + 287, + 424 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 369, + 287, + 424 + ], + "spans": [ + { + "bbox": [ + 53, + 369, + 287, + 424 + ], + "type": "text", + "content": "[7] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1290–1299, 2022. 4" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 425, + 287, + 468 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 425, + 287, + 468 + ], + "spans": [ + { + "bbox": [ + 53, + 425, + 287, + 468 + ], + "type": "text", + "content": "[8] Jiyu Cheng, Yuxiang Sun, and Max Q-H Meng. Improving monocular visual slam in dynamic environments: an optical-flow-based approach. Advanced Robotics, 33(12):576-589, 2019. 1" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 469, + 287, + 534 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 469, + 287, + 534 + ], + "spans": [ + { + "bbox": [ + 53, + 469, + 287, + 534 + ], + "type": "text", + "content": "[9] Alexey Dosovitskiy, Philipp Fischer, Eddy Ilg, Philip Hausser, Caner Hazirbas, Vladimir Golkov, Patrick Van Der Smagt, Daniel Cremers, and Thomas Brox. Flownet: Learning optical flow with convolutional networks. In the IEEE International Conference on Computer Vision (ICCV), pages 2758-2766, 2015. 1, 2, 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 536, + 287, + 579 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 536, + 287, + 579 + ], + "spans": [ + { + "bbox": [ + 48, + 536, + 287, + 579 + ], + "type": "text", + "content": "[10] Bo Du, Shihan Cai, and Chen Wu. Object tracking in satellite videos based on a multiframe optical flow tracker (j-stars). the IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 12(8):3043-3055, 2019. 1" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 580, + 287, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 580, + 287, + 624 + ], + "spans": [ + { + "bbox": [ + 48, + 580, + 287, + 624 + ], + "type": "text", + "content": "[11] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the kitti vision benchmark suite. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3354-3361, 2012. 1, 2, 5" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 625, + 287, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 625, + 287, + 679 + ], + "spans": [ + { + "bbox": [ + 48, + 625, + 287, + 679 + ], + "type": "text", + "content": "[12] Yunhui Han, Kunming Luo, Ao Luo, Jiangyu Liu, Haoqiang Fan, Guiming Luo, and Shuaicheng Liu. Realflow: Embased realistic optical flow dataset generation from videos. In the European Conference on Computer Vision (ECCV), pages 288-305, 2022. 1, 2, 3, 5, 6, 7, 8" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "type": "text", + "content": "[13] Yuxuan Han, Ruicheng Wang, and Jiaolong Yang. Single-view synthesis in the wild with learned adaptive multiplane images. In ACM SIGGRAPH, 2022. 2, 3, 4" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 307, + 73, + 547, + 148 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 547, + 148 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 547, + 148 + ], + "type": "text", + "content": "[14] Toshihide Hanari, Kuniaki Kawabata, and Keita Nakamura. Image selection method from image sequence to improve computational efficiency of 3d reconstruction: Analysis of inter-image displacement based on optical flow for evaluating 3d reconstruction performance. In the IEEE International Symposium on System Integration (SII), pages 1041-1045, 2022. 1" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 150, + 545, + 183 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 150, + 545, + 183 + ], + "spans": [ + { + "bbox": [ + 307, + 150, + 545, + 183 + ], + "type": "text", + "content": "[15] Anders Heyden and Marc Pollefeys. Multiple view geometry. Emerging topics in computer vision, 3:45-108, 2005. 4" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 185, + 546, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 185, + 546, + 239 + ], + "spans": [ + { + "bbox": [ + 308, + 185, + 546, + 239 + ], + "type": "text", + "content": "[16] Tak-Wai Hui, Xiaou Tang, and Chen Change Loy. Liteflownet: A lightweight convolutional neural network for optical flow estimation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 8981-8989, 2018. 2, 8" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 240, + 546, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 240, + 546, + 285 + ], + "spans": [ + { + "bbox": [ + 308, + 240, + 546, + 285 + ], + "type": "text", + "content": "[17] Junhwa Hur and Stefan Roth. Iterative residual refinement for joint optical flow and occlusion estimation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 5754-5763, 2019. 2, 8" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 286, + 546, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 286, + 546, + 342 + ], + "spans": [ + { + "bbox": [ + 308, + 286, + 546, + 342 + ], + "type": "text", + "content": "[18] Eddy Ig, Nikolaus Mayer, Tonmoy Saikia, Margret Keuper, Alexey Dosovitskiy, and Thomas Brox. Flownet 2.0: Evolution of optical flow estimation with deep networks. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 2462-2470, 2017. 1, 2, 5, 6, 9" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 342, + 546, + 386 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 342, + 546, + 386 + ], + "spans": [ + { + "bbox": [ + 308, + 342, + 546, + 386 + ], + "type": "text", + "content": "[19] Woobin Im, Tae-Kyun Kim, and Sung-Eui Yoon. Unsupervised learning of optical flow with deep feature similarity. In the European Conference on Computer Vision (ECCV), pages 172-188, 2020. 7" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 388, + 546, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 388, + 546, + 430 + ], + "spans": [ + { + "bbox": [ + 308, + 388, + 546, + 430 + ], + "type": "text", + "content": "[20] Woobin Im, Sebin Lee, and Sung-Eui Yoon. Semi-supervised learning of optical flow by flow supervisor. In the European Conference on Computer Vision (ECCV), pages 302-318, 2022. 7" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 433, + 546, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 433, + 546, + 487 + ], + "spans": [ + { + "bbox": [ + 308, + 433, + 546, + 487 + ], + "type": "text", + "content": "[21] Jisoo Jeong, Hong Cai, Risheek Garrepalli, and Fatih Porikli. Distractflow: Improving optical flow estimation via realistic distractions and pseudo-labeling. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 13691-13700, 2023. 7" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 488, + 546, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 488, + 546, + 533 + ], + "spans": [ + { + "bbox": [ + 308, + 488, + 546, + 533 + ], + "type": "text", + "content": "[22] Rico Jonschkowski, Austin Stone, Jonathan T Barron, Ariel Gordon, Kurt Konolige, and Anelia Angelova. What matters in unsupervised optical flow. In the European Conference on Computer Vision (ECCV), pages 557-572, 2020. 7" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 534, + 546, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 534, + 546, + 600 + ], + "spans": [ + { + "bbox": [ + 308, + 534, + 546, + 600 + ], + "type": "text", + "content": "[23] Artúr I Károly, Renata Nagyné Elek, Tamás Haidegger, Károly Széll, and Péter Galambos. Optical flow-based segmentation of moving objects for mobile robot navigation using pre-trained deep learning models. In the IEEE International Conference on Systems, Man and Cybernetics (SMC), pages 3080-3086, 2019. 1" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 601, + 546, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 601, + 546, + 645 + ], + "spans": [ + { + "bbox": [ + 308, + 601, + 546, + 645 + ], + "type": "text", + "content": "[24] Filippos Kokkinos and Iasonas Kokkinos. Learning monocular 3d reconstruction of articulated categories from motion. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1737-1746, 2021. 1" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 647, + 546, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 647, + 546, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 647, + 546, + 689 + ], + "type": "text", + "content": "[25] Wei-Sheng Lai, Jia-Bin Huang, and Ming-Hsuan Yang. Semi-supervised learning for optical flow with generative adversarial networks. Advances in Neural Information Processing Systems (NIPS), 30, 2017. 7" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 691, + 546, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 691, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 691, + 546, + 713 + ], + "type": "text", + "content": "[26] Jiaxin Li, Zijian Feng, Qi She, Henghui Ding, Changhu Wang, and Gim Hee Lee. Mine: Towards continuous depth" + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "text", + "content": "13866" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 73, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 67, + 73, + 287, + 105 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 73, + 287, + 105 + ], + "spans": [ + { + "bbox": [ + 67, + 73, + 287, + 105 + ], + "type": "text", + "content": "MPI with nerf for novel view synthesis. In the IEEE International Conference on Computer Vision (ICCV), pages 12578-12588, 2021. 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 287, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 287, + 162 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 287, + 162 + ], + "type": "text", + "content": "[27] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In the European Conference on Computer Vision (ECCV), pages 740-755, 2014. 5" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 163, + 287, + 229 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 163, + 287, + 229 + ], + "spans": [ + { + "bbox": [ + 49, + 163, + 287, + 229 + ], + "type": "text", + "content": "[28] Liang Liu, Jiangning Zhang, Ruifei He, Yong Liu, Yabiao Wang, Ying Tai, Donghao Luo, Chengjie Wang, Jilin Li, and Feiyue Huang. Learning by analogy: Reliable supervision from transformations for unsupervised optical flow estimation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 6489-6498, 2020. 7" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 231, + 287, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 231, + 287, + 274 + ], + "spans": [ + { + "bbox": [ + 49, + 231, + 287, + 274 + ], + "type": "text", + "content": "[29] Yubao Liu and Jun Miura. Rdmo-slam: Real-time visual slam for dynamic environments using semantic label prediction with optical flow. IEEE Access, 9:106981-106997, 2021. 1" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 276, + 287, + 319 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 276, + 287, + 319 + ], + "spans": [ + { + "bbox": [ + 49, + 276, + 287, + 319 + ], + "type": "text", + "content": "[30] Stephen Lombardi, Tomas Simon, Jason Saragih, Gabriel Schwartz, Andreas Lehrmann, and Yaser Sheikh. Neural volumes: Learning dynamic renderable volumes from images. arXiv preprint arXiv:1906.07751, 2019. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 321, + 287, + 364 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 321, + 287, + 364 + ], + "spans": [ + { + "bbox": [ + 49, + 321, + 287, + 364 + ], + "type": "text", + "content": "[31] Ao Luo, Fan Yang, Xin Li, and Shuaicheng Liu. Learning optical flow with kernel patch attention. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 8906-8915, 2022. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 366, + 287, + 409 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 366, + 287, + 409 + ], + "spans": [ + { + "bbox": [ + 49, + 366, + 287, + 409 + ], + "type": "text", + "content": "[32] Ao Luo, Fan Yang, Kunming Luo, Xin Li, Haoqiang Fan, and Shuaicheng Liu. Learning optical flow with adaptive graph reasoning. In the AAAI Conference on Artificial Intelligence, volume 36, pages 1890-1898, 2022. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 411, + 287, + 464 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 411, + 287, + 464 + ], + "spans": [ + { + "bbox": [ + 49, + 411, + 287, + 464 + ], + "type": "text", + "content": "[33] Kunming Luo, Chuan Wang, Shuaicheng Liu, Haoqiang Fan, Jue Wang, and Jian Sun. Upflow: Upsampling pyramid for unsupervised optical flow learning. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1045-1054, 2021. 7" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 468, + 287, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 468, + 287, + 510 + ], + "spans": [ + { + "bbox": [ + 49, + 468, + 287, + 510 + ], + "type": "text", + "content": "[34] Moritz Menze and Andreas Geiger. Object scene flow for autonomous vehicles. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3061-3070, 2015. 1, 2, 5" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 512, + 287, + 565 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 512, + 287, + 565 + ], + "spans": [ + { + "bbox": [ + 49, + 512, + 287, + 565 + ], + "type": "text", + "content": "[35] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 568, + 287, + 612 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 568, + 287, + 612 + ], + "spans": [ + { + "bbox": [ + 49, + 568, + 287, + 612 + ], + "type": "text", + "content": "[36] Chaerin Min, Taehyun Kim, and Jongwoo Lim. Meta-learning for adaptation of deep optical flow networks. In the IEEE Winter Conference on Applications of Computer Vision (WACV), pages 2145-2154, 2023. 7" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 49, + 614, + 287, + 677 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 614, + 287, + 677 + ], + "spans": [ + { + "bbox": [ + 49, + 614, + 287, + 677 + ], + "type": "text", + "content": "[37] Federico Perazzi, Jordi Pont-Tuset, Brian McWilliams, Luc Van Gool, Markus Gross, and Alexander Sorkine-Hornung. A benchmark dataset and evaluation methodology for video object segmentation. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 724-732, 2016. 5" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 49, + 681, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 681, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 49, + 681, + 287, + 713 + ], + "type": "text", + "content": "[38] René Ranftl, Katrin Lasinger, David Hafner, Konrad Schindler, and Vladlen Koltun. Towards robust monocular depth estimation: Mixing datasets for zero-shot cross-dataset" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "text", + "content": "transfer. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 44(3):1623-1637, 2020. 4" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 308, + 96, + 545, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 96, + 545, + 139 + ], + "spans": [ + { + "bbox": [ + 308, + 96, + 545, + 139 + ], + "type": "text", + "content": "[39] Chris Rockwell, David F Fouhey, and Justin Johnson. Pixelsynth: Generating a 3d-consistent experience from a single image. In the IEEE International Conference on Computer Vision (ICCV), pages 14104-14113, 2021. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 140, + 545, + 183 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 140, + 545, + 183 + ], + "spans": [ + { + "bbox": [ + 308, + 140, + 545, + 183 + ], + "type": "text", + "content": "[40] Robin Rombach, Patrick Esser, and Björn Ommer. Geometry-free view synthesis: Transformers and no 3d priors. In the IEEE International Conference on Computer Vision (ICCV), pages 14356-14366, 2021. 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 185, + 545, + 227 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 185, + 545, + 227 + ], + "spans": [ + { + "bbox": [ + 308, + 185, + 545, + 227 + ], + "type": "text", + "content": "[41] Nitin J Sanket, Chahat Deep Singh, Cornelia Fermüller, and Yiannis Aloimonos. Prgflow: Unified swap-aware deep global optical flow for aerial robot navigation. *Electronics Letters*, 57(16):614–617, 2021. 1" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 228, + 545, + 282 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 228, + 545, + 282 + ], + "spans": [ + { + "bbox": [ + 308, + 228, + 545, + 282 + ], + "type": "text", + "content": "[42] Austin Stone, Daniel Maurer, Alper Ayvaci, Anelia Angelova, and Rico Jonschkowski. Smurf: Self-teaching multiframe unsupervised raft with full-image warping. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3887-3896, 2021. 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 284, + 545, + 348 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 284, + 545, + 348 + ], + "spans": [ + { + "bbox": [ + 308, + 284, + 545, + 348 + ], + "type": "text", + "content": "[43] Deqing Sun, Daniel Vlasic, Charles Herrmann, Varun Jampani, Michael Krainin, Huiwen Chang, Ramin Zabih, William T Freeman, and Ce Liu. Autoflow: Learning a better training set for optical flow. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 10093-10102, 2021. 2, 8" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 350, + 545, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 350, + 545, + 403 + ], + "spans": [ + { + "bbox": [ + 308, + 350, + 545, + 403 + ], + "type": "text", + "content": "[44] Deqing Sun, Xiaodong Yang, Ming-Yu Liu, and Jan Kautz. Pwc-net: Cnns for optical flow using pyramid, warping, and cost volume. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 8934-8943, 2018. 1, 2, 8, 9" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 404, + 545, + 437 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 404, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 308, + 404, + 545, + 437 + ], + "type": "text", + "content": "[45] Zachary Teed and Jia Deng. Raft: Recurrent all-pairs field transforms for optical flow. In the European Conference on Computer Vision (ECCV), pages 402-419, 2020. 1, 2, 5, 8, 9" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 438, + 545, + 469 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 438, + 545, + 469 + ], + "spans": [ + { + "bbox": [ + 308, + 438, + 545, + 469 + ], + "type": "text", + "content": "[46] Alexandru Telea. An image inpainting technique based on the fast marching method. Journal of graphics tools, 9(1):23-34, 2004. 4" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 472, + 545, + 514 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 472, + 545, + 514 + ], + "spans": [ + { + "bbox": [ + 308, + 472, + 545, + 514 + ], + "type": "text", + "content": "[47] Richard Tucker and Noah Snively. Single-view view synthesis with multiplane images. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 551-560, 2020. 2, 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 515, + 545, + 558 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 515, + 545, + 558 + ], + "spans": [ + { + "bbox": [ + 308, + 515, + 545, + 558 + ], + "type": "text", + "content": "[48] Shubham Tulsiani, Richard Tucker, and Noah Snavely. Layer-structured 3d scene inference via view synthesis. In the European Conference on Computer Vision (ECCV), pages 302–317, 2018. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 559, + 545, + 612 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 559, + 545, + 612 + ], + "spans": [ + { + "bbox": [ + 308, + 559, + 545, + 612 + ], + "type": "text", + "content": "[49] Philippe Weinzaepfel, Jerome Revaud, Zaid Harchaoui, and Cordelia Schmid. Deepflow: Large displacement optical flow with deep matching. In the IEEE International Conference on Computer Vision (ICCV), pages 1385-1392, 2013. 1, 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 614, + 545, + 647 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 614, + 545, + 647 + ], + "spans": [ + { + "bbox": [ + 308, + 614, + 545, + 647 + ], + "type": "text", + "content": "[50] Christopher Zach, Thomas Pock, and Horst Bischof. A duality based approach for realtime tv-l 1 optical flow. In Pattern Recognition, pages 214-223, 2007. 1" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 647, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 647, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 647, + 545, + 689 + ], + "type": "text", + "content": "[51] Jimuyang Zhang, Sanping Zhou, Xin Chang, Fangbin Wan, Jinjun Wang, Yang Wu, and Dong Huang. Multiple object tracking by flowing and fusing. arXiv preprint arXiv:2001.11180, 2020. 1" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "text", + "content": "[52] Tianwei Zhang, Huayan Zhang, Yang Li, Yoshihiko Nakamura, and Lei Zhang. Flowfusion: Dynamic dense rgb-d" + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "13867" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 205 + ], + "type": "list", + "angle": 0, + "index": 3, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "type": "text", + "content": "slam based on optical flow. In the IEEE International Conference on Robotics and Automation (ICRA), pages 7322-7328, 2020. 1" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 287, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 287, + 149 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 287, + 149 + ], + "type": "text", + "content": "[53] Tinghui Zhou, Richard Tucker, John Flynn, Graham Fyffe, and Noah Snavely. Stereo magnification: Learning view synthesis using multiplane images. In ACM SIGGRAPH, 2018. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 152, + 287, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 152, + 287, + 205 + ], + "spans": [ + { + "bbox": [ + 48, + 152, + 287, + 205 + ], + "type": "text", + "content": "[54] Yuemei Zhou, Gaochang Wu, Ying Fu, Kun Li, and Yebin Liu. Cross-mpi: Cross-scale stereo for image super-resolution using multiplane images. In the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 14842-14851, 2021. 2" + } + ] + } + ], + "index": 2 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "13868" + } + ] + } + ], + "index": 4 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 11 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/3ca9548a-636d-4952-80cd-106e032bd384_content_list.json b/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/3ca9548a-636d-4952-80cd-106e032bd384_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..5f66e89ecf8bdd5b4b3cf00c6b5f13a74c4992ef --- /dev/null +++ b/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/3ca9548a-636d-4952-80cd-106e032bd384_content_list.json @@ -0,0 +1,1807 @@ +[ + { + "type": "text", + "text": "MRM: Masked Relation Modeling for Medical Image Pre-Training with Genetics", + "text_level": 1, + "bbox": [ + 76, + 130, + 893, + 154 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Qiushi Yang", + "bbox": [ + 225, + 179, + 336, + 199 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Wuyang Li", + "bbox": [ + 372, + 180, + 470, + 198 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Baopu Li3", + "bbox": [ + 511, + 180, + 596, + 198 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Yixuan Yuan $^{1,2*}$", + "bbox": [ + 637, + 180, + 766, + 196 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{1}$ City University of Hong Kong $^{2}$ The Chinese University of Hong Kong $^{3}$ Independent Researcher", + "bbox": [ + 197, + 200, + 790, + 215 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{qsyang2-c, wuyangli2-c}@my.cityu.edu.hk.", + "bbox": [ + 89, + 219, + 450, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "bpliu.cuhk@gmail.com", + "bbox": [ + 508, + 219, + 681, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "yxyuan@ee.cuhk.edu.hk", + "bbox": [ + 712, + 220, + 900, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 268, + 313, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Modern deep learning techniques on automatic multimodal medical diagnosis rely on massive expert annotations, which is time-consuming and prohibitive. Recent masked image modeling (MIM)-based pre-training methods have witnessed impressive advances for learning meaningful representations from unlabeled data and transferring to downstream tasks. However, these methods focus on natural images and ignore the specific properties of medical data, yielding unsatisfying generalization performance on downstream medical diagnosis. In this paper, we aim to leverage genetics to boost image pre-training and present a masked relation modeling (MRM) framework. Instead of explicitly masking input data in previous MIM methods leading to loss of disease-related semantics, we design relation masking to mask out token-wise feature relation in both self- and cross-modality levels, which preserves intact semantics within the input and allows the model to learn rich disease-related information. Moreover, to enhance semantic relation modeling, we propose relation matching to align the sample-wise relation between the intact and masked features. The relation matching exploits inter-sample relation by encouraging global constraints in the feature space to render sufficient semantic relation for feature representation. Extensive experiments demonstrate that the proposed framework is simple yet powerful, achieving state-of-the-art transfer performance on various downstream diagnosis tasks. Codes are available at https://github.com/CityU-AIM-Group/MRM.", + "bbox": [ + 75, + 300, + 473, + 724 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 753, + 209, + 768 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In the medical diagnosis [44, 34, 38, 28, 6, 5], the largescale multimodal biobank data, e.g., images and genetics, is necessary for a reliable diagnosis, overcoming the limited scale and disease information of a single-modality", + "bbox": [ + 75, + 779, + 468, + 840 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/6b0ce549fceda1ce6a9605b5b97bcd214d2b76ee6e91b598128d86a8e9eacd0a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 506, + 273, + 697, + 356 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/f18ab18d9d702730946f58a822f9406fb304a8098ba1f0589b24879b8a0ce28a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 697, + 276, + 887, + 356 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/3f1dd1d615c93a1dbd8d2feea6c1614cf1c70b5e9e079b9198c166c2c3756294.jpg", + "image_caption": [ + "Figure 1. Comparison of different masking strategies on natural and medical data. (a): Existing MIM methods mask out input natural images and infer the missing content to learn semantic representations via reconstruction task. (b): Recent pre-training approaches for disease diagnosis explicitly employ MIM on input medical data (e.g., medical images and genome), whilst they are prone to lose tiny disease regions and cause non-tractable reconstruction. (c): Our method masks token-wise feature relation across multimodal data and matches sample-wise relation between the intact and masked features, preserving intact semantic regions and enriching relation information." + ], + "image_footnote": [], + "bbox": [ + 506, + 358, + 697, + 443 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/85c3242344fc994459dc4baa0aa4f84e019cb7b0548b4c6e11a08ea5b156c504.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 697, + 359, + 887, + 443 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "dataset. However, the prohibitive expert annotations of large-scale datasets make it difficult to train a conventional deep model [44, 45, 41, 46, 47]. Particularly, in this multimodal scenario, the requirements of the experts in various medical fields prevent enough annotation access, severely limiting the grounding of the automatic diagnosis system.", + "bbox": [ + 496, + 640, + 893, + 733 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "To address this, the most prospering trend [16, 43, 4, 34, 13, 35, 36, 12, 27] is self-supervised pre-training, e.g., masked image modeling (MIM) [16, 43, 13, 42], aiming to train a label-free model with adequate generalization capacity. Existing MIM methods [16, 43, 4, 25, 13, 42, 49] mask out a high portion of patches within input images and infer the missing content, as suggested in Figure 1 (a). They make use of contextual information to glance the semantics and reconstruct the entire images, which performs a mask-and-reconstruct task to pre-train the model without annotation and transfer meaningful representations to various", + "bbox": [ + 496, + 734, + 895, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding author.", + "bbox": [ + 94, + 851, + 222, + 863 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "This work was supported by Hong Kong Research Grants Council (RGC) General Research Fund 14220622, 14204321, and Innovation and Technology Commission-Innovation and Technology Fund ITS/100/20.", + "bbox": [ + 76, + 863, + 468, + 900 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "21452", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "downstream tasks for improving label-efficient fine-tuning.", + "bbox": [ + 76, + 90, + 465, + 104 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Though achieving great success, most works [16, 43, 4, 40, 10, 25, 19] are designed for natural images, ignoring the essential differences between medical data and natural images. Therefore, we empirically find that existing MIM CANNOT works well in medical data (see Table 1), and even totally fails to reconstruct diseases (see Figure 3). The reasons derive from a critical observation regarding the significant data differences, which can be summarized into two challenges. Firstly, compared with natural images, there are limited semantic regions in medical data. As shown in Figure 1 (a), the semantic-rich foreground is always the main body of the natural image, while the rest non-informative background region only represents a minority part. Differently, in the medical image (Figure 1 (b)), the majority of regions are backgrounds, and the informative disease regions are usually on a tiny scale. Under the strategy of masking entire tokens in existing MIM methods [16, 43, 4, 40, 10, 25, 19], if the disease tokens are masked out, the disease-related semantic is totally missing with a catastrophic information loss, leading to a nontractable reconstruction. This issue also exists between genomics and natural images. The semantic regions in genomics, i.e., the disease-related patterns, mainly lie in a minority of genome segments [28, 5, 7]. Hence, instead of masking the whole input token, these observations motivate us to delve into the masking of token-level relation, which preserves abundant semantic discriminability and adequate self-supervision, as illustrated in Figure 1 (c) Left.", + "bbox": [ + 75, + 109, + 468, + 532 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The second challenge is the limited semantic relation. In a natural image, the background and foreground relationship, e.g., the bird in the sky and the person in a room, tends to be prosperous and abundant, serving a critical role in semantic-level learning [39, 24]. In contrast, in each medical data sample, the disease-aware relation is limited and insufficient to provide enough discriminative evidence. The reason lies in that the medical datasets are usually collected from the same human organ, e.g., the fundus, containing redundant and similar anatomical patterns, e.g., the capillary, which severely prevent the relation modeling between the disease and the complex medical scene. This challenge hampers reliable relation learning in existing MIM methods, and may incur an inevitable overfitting to noninformative relation within the background [40, 25, 23, 3]. Hence, considering the limited semantic relation in each data sample, we are committed to going beyond the self-supervised learning for an independent and individual data sample, and propose to encourage global constraints for exploiting inter-sample relation (see Figure 1 (c) Right).", + "bbox": [ + 75, + 535, + 468, + 837 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To combat above challenges, as shown in Figure 1 (c), we present MRM, a masked relation modeling from a unified view of relation, containing relation masking and relation matching, to rationally pre-train multimodal medical", + "bbox": [ + 75, + 839, + 468, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "images with genetics. To preserve intact semantic information within raw input, we devise relation masking strategy to allow the model to learn disease-related semantics. Instead of masking out input data, the relation masking investigates token-wise relation within feature representations in both self- and cross-modality levels and masks out the relation among all multimodal tokens. The relation masking endows the model to explicitly learn global dependency from raw data without missing disease-related semantic information. Furthermore, to improve the semantic relation modeling, the relation matching is designed to provide global constraint by aligning the feature relation across multiple samples. Specifically, relation matching exploits sample-wise relation in both self- and cross-modality levels to encourage the relation consistency between the intact and masked features. This enjoys the complementary advantages of persample pixel-wise reconstruction loss and boosts the transfer ability of the model. With the pre-trained model, we can obtain the feature representation that can be transferred to supervised downstream diagnosis tasks for boosting label-efficient fine-tuning, alleviating the severe demand for specialized annotations.", + "bbox": [ + 496, + 90, + 890, + 421 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In summary, our contributions fall into four parts:", + "bbox": [ + 517, + 424, + 846, + 439 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We identify the challenges of current MIM methods on medical data, and present MRM, a masked relation modeling using multimodal medical data to facilitate image representation learning.", + "- Towards the issue of limited semantic regions in medical data, we design relation masking to mask tokenwise feature relation across self- and cross-modality. Different from MIM explicitly masking inputs, relation masking preserves disease semantics within inputs, endowing a powerful mask-and-construct task.", + "- Moreover, to enrich the semantic relation among diseases, the relation matching is proposed to capture abundant disease-related relation by aligning sample-wise feature relation between intact and masked features in both self- and cross-modality levels.", + "- Extensive transfer evaluation on various downstream tasks using two public medical pre-training datasets demonstrate that our framework performs superior transfer ability over state-of-the-art methods." + ], + "bbox": [ + 517, + 450, + 890, + 777 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 805, + 640, + 821 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Visual Pre-training", + "text_level": 1, + "bbox": [ + 500, + 830, + 684, + 847 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In recent years, self-supervised visual pre-training [8, 9, 15, 17, 11, 16, 43, 48, 4] has achieved exceptional transfer performance in various downstream visual tasks, which", + "bbox": [ + 500, + 854, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "21453", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/3b4916f3987b8ea0e696a6ff15de0887dc8eb89915e6fe6b20443e8b644423d6.jpg", + "image_caption": [ + "Figure 2. Overview of masked relation modeling (MRM). MRM contains relation masking to mask out token-wise feature relation with preserving disease-related semantics, and the relation matching to enforce sample-wise relation consistency for global semantic modeling." + ], + "image_footnote": [], + "bbox": [ + 83, + 95, + 885, + 330 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "can be divided into two categories. The first is contrastive-based methods [8, 15, 17, 35, 35] that aim to project similar samples nearby while pull dissimilar ones far away in the feature space. For instance, SimCLR [8] imposes two embeddings from a sample under different views consistency via InfoNCE loss, and BYOL [15] merely pushes the positive pairs together with a momentum encoder for boosting transfer performance. Moreover, inspired by the progress of masked language modeling on natural language processing [20], masked image modeling (MIM)-based approaches [16, 48, 43, 4, 3, 10, 3] are proposed to pre-train visual models and exhibit remarkable transfer performance. MAE [16] formulates a pixel-wise reconstruction task to mask out a high portion of input patches and infer the masked ones with visible tokens via an autoencoder. Afterwards, many followups [43, 3, 19, 10] devise MIM models to improve the representation learning. However, they mainly focus on natural images and ignore the essential differences between the medical data and natural images, thereby delivering unsatisfying transfer results [27, 49].", + "bbox": [ + 75, + 404, + 472, + 705 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Medical Self-supervised Learning", + "text_level": 1, + "bbox": [ + 76, + 723, + 372, + 739 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Most works [35, 36, 2, 34] on medical self-supervised learning extend the ideas of contrastive learning and develop customized strategies to pre-train models. 3DSSL [36] adopt a series of proxy tasks to present a 3D versions self-supervised model and achieves compelling transfer results. ContIG [34] crafts a multimodal pre-training framework using image and genome data via contrastive learning and delivers competitive transfer ability. Although efficiency, these contrastive-based approaches strongly rely on well-defined data augmentations to construct positive", + "bbox": [ + 75, + 750, + 468, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "pairs, which are difficult for medical data, especially for structured data, e.g., genetics. Most recently, some studies [13, 42, 27, 49] adopt MIM to self-supervised pre-train medical models. MedicalMAE [49] introduces a self pretraining paradigm by employing MAE [16] to pre-train the model and achieve superior performance. To perform multimodal pre-training, $\\mathrm{M}^{3}\\mathrm{3AE}$ [13] randomly masks out the tokens of image and language inputs and aims to infer the whole data using visible tokens. All of them still adopt input masking strategy, which may incur tiny disease-related region missing and non-tractable reconstruction. Differently, we design a novel relation masking strategy in the feature space and retain intact disease-related information.", + "bbox": [ + 496, + 404, + 890, + 601 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.3. Learning from Images and Genetics", + "text_level": 1, + "bbox": [ + 500, + 628, + 812, + 645 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Genetics can provide comprehensive information for many disease diagnosis and treatment planning [38, 28, 6, 5, 7], which attract much attention from researchers. Many works [44, 34, 38] formulate a multimodal learning task by jointly leveraging genetics and medical images to exploit complementary knowledge. Considering that the genetics may be difficult to acquire in many clinical applications, recent studies [34, 7] aim to design pre-training models using images and genetics for improving practical image-based diagnosis. However, they merely use contrastive constraint to perform self-supervised learning, while they fail to adopt the efficient mask-and-reconstruct task to pre-train models. In this work, we aim to leverage genetics with images to boost the visual representation learning via semantic relation modeling, which discovers both inner-sample and intersample relation to achieve more effective pre-training.", + "bbox": [ + 496, + 659, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "21454", + "bbox": [ + 478, + 944, + 519, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Masked Relation Modeling", + "text_level": 1, + "bbox": [ + 76, + 89, + 328, + 107 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In this section, we start by introducing the preliminaries of vision Transformer and masked image modeling. We then present the masked relation modeling (MRM), containing relation masking and relation matching. The overall pre-training and transfer inference of the framework are described at the end of the section.", + "bbox": [ + 75, + 114, + 468, + 205 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.1. Preliminaries", + "text_level": 1, + "bbox": [ + 76, + 214, + 217, + 229 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Vision Transformer (ViT). Given an image $x \\in \\mathbb{R}^{c \\times h \\times w}$ , ViT first splits it into $n = hw / p^2$ non-overlapping patches $x_P = \\{x_1; x_2; \\ldots; x_n\\}$ , $x_i \\in \\mathbb{R}^{c \\times p \\times p}$ , where $p \\times p$ denotes the size of each patch. Afterwards, the patches $x_P$ are tokenized as a sequence of token embeddings $e = \\{e_1; e_2; \\ldots; e_n\\}$ , $e_i \\in \\mathbb{R}^{1 \\times d}$ , where $d$ is the dimension of each token, via a linear projection with positional embeddings. The embeddings $e$ are then processed by a cascade of multi-head self-attention layers to capture global information, where the self-attention is described as follow:", + "bbox": [ + 75, + 237, + 470, + 388 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {A t t e n t i o n} (e) = \\operatorname {S o f t m a x} \\left(\\frac {1}{\\sqrt {d}} Q K ^ {T}\\right) V, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 143, + 397, + 468, + 429 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $K = eW^{K}$ , $Q = eW^{Q}$ , $V = eW^{V}$ , $K, Q, V \\in \\mathbb{R}^{1 \\times d}$ is the key, query and value obtained by the linear projection via $W^{K}, W^{Q}, W^{V}$ , respectively. Each layer of the ViT encoder contains a multi-head self-attention block, and the feature representation is produced by multiple layers within the encoder.", + "bbox": [ + 75, + 438, + 468, + 529 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Masked Image Modeling (MIM). The input patches $x_{p}$ are randomly masked out with a high ratio, denoted as masked patches $x_{M}$ . The remaining visible patches $x_{V}$ are fed into ViT encoder $f(\\cdot)$ to capture features $z = f(x_{V})$ , which are then sent to a lightweight decoder $h(\\cdot)$ to recover the missing patches $\\hat{x} = h(z)$ of the input data. The overall framework is optimized by mean-squared error (MSE) reconstruction loss function $\\mathcal{L}_{\\mathrm{MIM}}$ between the recovered patches $\\hat{x}$ and masked patches $x_{M}$ as:", + "bbox": [ + 75, + 530, + 468, + 667 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {M I M}} = \\mathbb {E} | | x _ {M} - h (f (x _ {V})) | | _ {2} ^ {2}. \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 166, + 676, + 468, + 694 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Overview of Masked Relation Modeling (MRM). As illustrated in Figure 2, the proposed MRM consists of the relation masking strategy to mask out feature relation and preserve intact disease-related semantics, and the relation matching to offer global constraints for relation modeling. With the input image $x_{I}$ and genome $x_{G}$ , the ViT encoder $f_{I}$ and self-normalizing network (SNN) [22] $f_{G}$ produces masked feature representations $z_{I,M},z_{G,M}$ for image and genome via relation masking. Parallely, the intact representations $z_{I},z_{G}$ are obtained by two encoders without relation masking. Afterwards, the masked features $z_{I,M},z_{G,M}$ are aggregated with the intact features $z_{G},z_{I}$ from the other modality to yield the fused features $z_{I}^{F},z_{G}^{F}$ , respectively.", + "bbox": [ + 75, + 703, + 470, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "These fused feature are then put into the image decoder $h_I$ and the genome decoder $h_G$ to reconstruct original data $\\hat{x}_I$ and $\\hat{x}_G$ . The relation matching is employed on intact and masked feature representations with the data reconstruction loss to jointly optimize the overall framework.", + "bbox": [ + 496, + 90, + 890, + 167 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Relation Masking", + "text_level": 1, + "bbox": [ + 500, + 172, + 671, + 189 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Due to the medical data usually appearing tiny disease patterns, current input-level masking strategies may discard disease-related semantics and hardly learn informative feature representation. To address this problem, the relation masking is proposed to mask token-wise feature relation from self- and cross-modality perspectives in a cascading manner, which can maintain intact input disease-related information during pre-training. The operations of relation masking for image and genome are parallel, for brevity, we adopt the image branch to introduce.", + "bbox": [ + 496, + 196, + 890, + 347 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Self-modality relation masking. In the $i$ -th relation masking block, given $z_{I}^{0}$ as the input image token, we first calculate $K_{I}^{S}, Q_{I}^{S}, V_{I}^{S}$ as its key, query and value, respectively. Then, the normalized feature dependency in tokens is obtained by computing the relation between the key $K_{I}^{S}$ and query $Q_{I}^{S}$ of the image feature as follows:", + "bbox": [ + 496, + 347, + 890, + 439 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nR _ {\\text {s e l f}} = \\operatorname {S o f t m a x} \\left(\\frac {1}{\\sqrt {d}} Q _ {I} ^ {S} \\cdot \\left(K _ {I} ^ {S}\\right) ^ {T}\\right). \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 576, + 444, + 890, + 476 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "This self-modality relation $R_{\\mathrm{self}}$ reflects the token-wise semantic correspondence within the image feature. The tokens with stronger relation contain more interactive and informative semantics. To enable the model to capture intramodality feature representation via the reconstruction task, on the top of self-modality relation, we aim to break the strong dependency across informative regions by relation masking. Specifically, we mask out high-intensity elements with a ratio $\\tau_I$ in self-modality relation:", + "bbox": [ + 496, + 479, + 890, + 616 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nR _ {\\text {s e l f}} ^ {M} [ p, q ] = \\left\\{ \\begin{array}{c c} R _ {\\text {s e l f}} [ p, q ] & \\text {i f} R _ {\\text {s e l f}} [ p, q ] < r _ {\\text {s e l f}} ^ {p} \\\\ 0 & \\text {e l s e ,} \\end{array} \\right. \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 524, + 619, + 890, + 654 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $r_{\\mathrm{self}}^p$ refers to the intensity of the top- $\\tau_I$ element among the $p$ -th row of the self-modality relation $R_{\\mathrm{self}}$ matrix. Note that the masked elements are selected in each row of the self-modality relation matrix to remove the semantic correspondence for all tokens with the same intensity. Afterwards, the masked relation matrix $R_{\\mathrm{self}}^M$ is forwarded to produce the token $z_I^S = R_{\\mathrm{self}}^M V_I^S$ for subsequent data flow. With the self-modality relation masking, the relative important dependency within the modality is discarded and we enforce the model to reconstruct the original image with the remaining weak feature relation. Thus, the model can capture disease-related feature representation of images.", + "bbox": [ + 496, + 657, + 890, + 839 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Cross-modality relation masking. In an attempt to incorporate multimodal knowledge, after the self-modality self-attention layer, we perform cross-modality attention between the image and genome features. Precisely, obtained", + "bbox": [ + 496, + 839, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "21455", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "the image and genome tokens $z_{I}^{S},z_{G}^{S}$ masked via selfmodality relation masking, we compute token-wise crossmodality relation to capture semantic correspondence between image and genome features:", + "bbox": [ + 75, + 90, + 468, + 151 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nR _ {\\text {c r o s s}} = \\operatorname {S o f t m a x} \\left(\\frac {1}{\\sqrt {d}} Q _ {I} ^ {C} \\cdot \\left(K _ {G} ^ {C}\\right) ^ {T}\\right), \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 148, + 162, + 468, + 196 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $K_{G}^{C}$ means the key of genome feature $z_{G}^{S}$ , and $Q_{I}^{C}$ represents the query of image feature $z_{I}^{S}$ in the cross-attention layer. This cross-modality attention can amalgamate two modality knowledge and improve the feature representation towards disease-related information. Then, to allow the model to learn complementary multimodal knowledge and the relation between two modalities, we perform cross-modality relation masking by removing strong semantic correspondence between image and genome features:", + "bbox": [ + 75, + 208, + 470, + 358 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nR _ {\\text {c r o s s}} ^ {M} [ p, q ] = \\left\\{ \\begin{array}{c l} R _ {\\text {c r o s s}} [ p, q ] & \\text {i f} R _ {\\text {c r o s s}} [ p, q ] < r _ {\\text {c r o s s}} ^ {p} \\\\ 0 & \\text {e l s e ,} \\end{array} \\right. \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 86, + 369, + 468, + 404 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $r_{\\mathrm{cross}}^p$ denotes the intensity of the top- $\\tau_I$ element among the $p$ -th row of the cross-modality relation matrix $R_{\\mathrm{cross}}$ . With the masked relation $R_{\\mathrm{cross}}^M$ , we can obtain the fused image token $z_I^C = R_{\\mathrm{cross}}^M V_G^C$ , where $V_G^C$ means the value of the genome feature.", + "bbox": [ + 76, + 416, + 468, + 492 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Reconstruction with relation masking. We feed the input data into two networks shared parameters, where the first network consists of a ViT encoder to yield intact image feature $z_{I}$ and a SNN encoder with self-attention blocks to produce genome feature $z_{G}$ . Parallely, the second network employs the proposed self- and cross-modality relation masking in first two attention blocks to generate masked features $z_{I,M}, z_{G,M}$ for image and genome, respectively. Afterwards, the masked features are incorporated with the intact feature from the other modality and produce amalgamated features $z_{I}^{F} = \\text{concat}[z_{I,M}; z_{G}]$ , $z_{G}^{F} = \\text{concat}[z_{G,M}; z_{I}]$ for images and genome. The fused features are then put into the decoders $h_{I}(\\cdot), h_{G}(\\cdot)$ to reconstruct image and genome $\\hat{x}_{I} = h_{I}(z_{I}^{F}), \\hat{x}_{G} = h_{G}(z_{G}^{F})$ . The overall loss function for the reconstruction of image and genome is:", + "bbox": [ + 75, + 493, + 468, + 720 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {r e c o n}} = \\left\\| h _ {I} \\left(z _ {I} ^ {F}\\right) - x _ {I} \\right\\| _ {2} ^ {2} + \\left\\| h _ {G} \\left(z _ {G} ^ {F}\\right) - x _ {G} \\right\\| _ {2} ^ {2}. \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 104, + 732, + 468, + 752 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The relation masking strategy exploits the token-wise feature relation for mask-and-reconstruct task. It is worth noting that although the strong relation is removed, the intrinsic information within the data is retained [32]. Therefore, with the original complete image and genome as inputs, our relation masking can preserve the intact disease-related semantics. With the relation masking-based reconstruction task, the self-modality relation is encouraged to be recovered by the model to capture disease-related information", + "bbox": [ + 75, + 763, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "within each modality, and the cross-modality relation is enforced to reconstruct to learn abundant multimodal knowledge to improve the disease-related representation for effective downstream diagnosis tasks transfer.", + "bbox": [ + 498, + 90, + 890, + 151 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.3. Relation Matching", + "text_level": 1, + "bbox": [ + 500, + 160, + 679, + 176 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Considering that the disease-aware relation among diseases is limited in medical data, to provide sufficient semantic relation, we propose relation matching, a global constraint to align the sample-wise relation across self- and cross-modality samples to perform global constraints in the feature space.", + "bbox": [ + 498, + 183, + 890, + 273 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Self-modality matching. Assume one minibatch contains $B$ multimodal pairs $\\{x_I^i,x_G^i\\}_{i = 1}^B$ , we can obtain the intact feature representations $\\{z_I^i,z_G^i\\}_{i = 1}^B$ and masked ones $\\{z_{I,M}^{i},z_{G,M}^{i}\\}_{i = 1}^{B}$ via the proposed relation masking strategy. Firstly, we compute the sample-wise relation $\\{R_{\\mathrm{II}}^{i,j}\\}_{i,j = 1}^{B},\\{R_{\\mathrm{GG}}^{i,j}\\}_{i,j = 1}^{B}$ across all intact features of image and genome, respectively:", + "bbox": [ + 498, + 273, + 890, + 378 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nR _ {\\mathrm {I I}} ^ {i, j} = \\operatorname {s i m} \\left(z _ {I} ^ {i}; z _ {I} ^ {j}\\right) \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 625, + 388, + 890, + 415 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nR _ {\\mathrm {G G}} ^ {i, j} = \\operatorname {s i m} \\left(z _ {G} ^ {i}; z _ {G} ^ {j}\\right),\n$$\n", + "text_format": "latex", + "bbox": [ + 625, + 410, + 764, + 429 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathrm{sim}(\\cdot ;\\cdot)$ denotes the similarity between two features, here we adopt the cosine similarity. Similarly, we acquire the sample relation among masked features:", + "bbox": [ + 498, + 438, + 890, + 483 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nR _ {\\mathrm {I I}, \\mathrm {M}} ^ {i, j} = \\operatorname {s i m} \\left(z _ {I, M} ^ {i}; z _ {I, M} ^ {j}\\right), \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 609, + 492, + 890, + 518 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nR _ {\\mathrm {G G}, \\mathrm {M}} ^ {i, j} = \\operatorname {s i m} (z _ {G, M} ^ {i}; z _ {G, M} ^ {j}).\n$$\n", + "text_format": "latex", + "bbox": [ + 602, + 515, + 789, + 534 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We aim to ensure the relation consistency between intact and masked features. The matching objective for self-modality feature relation can be formulated as:", + "bbox": [ + 498, + 542, + 890, + 588 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {s e l f}} = \\frac {1}{2 B ^ {2}} \\sum_ {i = 1} ^ {B} \\sum_ {j = 1} ^ {B} \\left| \\left| R _ {\\mathrm {I I}} ^ {i, j} - R _ {\\mathrm {I I}, \\mathrm {M}} ^ {i, j} \\right| \\right| _ {2} ^ {2} + \\left| \\left| R _ {\\mathrm {G G}} ^ {i, j} - R _ {\\mathrm {G G}, \\mathrm {M}} ^ {i, j} \\right| \\right| _ {2} ^ {2}. \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 500, + 597, + 890, + 652 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Cross-modality matching. Furthermore, to incorporate multimodal information and bridge the gap of different modalities, we compute the cross-modality relation:", + "bbox": [ + 498, + 652, + 890, + 699 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nR _ {\\mathrm {I G}} ^ {i, j} = \\operatorname {s i m} \\left(z _ {I} ^ {i}; z _ {G} ^ {j}\\right), \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 614, + 707, + 890, + 734 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nR _ {\\mathrm {I G , M}} ^ {i, j} = \\mathrm {s i m} (z _ {I, M} ^ {i}; z _ {G, M} ^ {j}),\n$$\n", + "text_format": "latex", + "bbox": [ + 607, + 729, + 785, + 750 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\{R_{\\mathrm{IG}}^{i,j}\\}_{i,j = 1}^{B}$ represents the cross-modality relation across intact multimodal features, and $\\{R_{\\mathrm{IG,M}}^{i,j}\\}_{i,j = 1}^{B}$ means the relation across masked ones. We intend to ensure the cross-modality relation to be invariant between masked and intact features. The cross-modality feature relation can be calculated as:", + "bbox": [ + 498, + 758, + 890, + 852 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {c r o s s}} = \\frac {1}{B ^ {2}} \\sum_ {i = 1} ^ {B} \\sum_ {j = 1} ^ {B} \\left| \\left| R _ {\\mathrm {I G}} ^ {i, j} - R _ {\\mathrm {I G}, \\mathrm {M}} ^ {i, j} \\right| \\right| _ {2} ^ {2}. \\tag {12}\n$$\n", + "text_format": "latex", + "bbox": [ + 566, + 859, + 890, + 902 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "21456", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/ea6ac4b1650523cb0b54879127f4e73ebf0341756be6c44e4efb67002ea48ea5.jpg", + "table_caption": [ + "Table 1. Comparison with state-of-the-art pre-training algorithms via fine-tuning evaluation on four downstream retinal image-based tasks." + ], + "table_footnote": [], + "table_body": "
MethodMasking LevelAPTOSRFMiDPALMCRP
InputRelationQwKappa ↑ROC-AUC ↑Dice-Score ↑MSE ↓ROC-AUC ↑
Training from scratch (baseline)--83.2592.9179.443.40558.05
Contrastive-based Pre-training Methods
SimCLR [8]--84.5093.7573.183.42663.92
MoCo v3 [17]--85.0394.0275.733.42165.33
ContIG [34]--86.2794.5980.253.18473.57
MIM-based Pre-Training Methods
MAE [16]✓✗84.0692.7174.283.48864.29
SimMIM [43]✓✗84.6793.8072.733.45066.08
MultiMAE [3]✓✗85.5994.2675.923.41167.51
M3AE [13]✓✗86.8594.7277.353.39468.39
mc-BEiT [25]✓✗87.1594.3777.403.37266.38
AttMask [19]✓✗87.7394.9178.593.26269.40
MRM✗✓89.8396.3181.453.10775.90
", + "bbox": [ + 84, + 101, + 885, + 280 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "With the self- and cross-modality feature relation, we can formulate the overall relation matching objective as:", + "bbox": [ + 76, + 304, + 468, + 335 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {m a t c h}} = \\mathcal {L} _ {\\text {s e l f}} + \\mathcal {L} _ {\\text {c r o s s}}. \\tag {13}\n$$\n", + "text_format": "latex", + "bbox": [ + 194, + 342, + 468, + 357 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The relation matching encourages global constraints in the feature space to provide sufficient semantic relation, which enjoys the complementary advantages of pixel-wise data reconstruction loss in Eq. (7).", + "bbox": [ + 76, + 364, + 468, + 425 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "3.4. Pre-training and Transfer Inference", + "text_level": 1, + "bbox": [ + 76, + 431, + 388, + 448 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In the pre-training phase, the image and genome as multimodal inputs are fed into the model. We adopt the proposed relation masking to generate masked features, and employ the relation matching as the global constraint with the data reconstruction loss to jointly optimize the overall framework:", + "bbox": [ + 75, + 455, + 468, + 545 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {o v e r a l l}} = \\mathcal {L} _ {\\text {r e c o n}} + \\lambda \\mathcal {L} _ {\\text {m a t c h}}, \\tag {14}\n$$\n", + "text_format": "latex", + "bbox": [ + 181, + 553, + 468, + 569 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $\\lambda$ denotes the balanced coefficient to control contributions of the reconstruction task and the relation matching. During the phase of downstream image-based fine-tuning, we discard the genome branch and utilize the image encoder to extract the feature representation without relation masking. The pre-trained encoder following a randomly initial task-relevant head is fine-tuned on downstream tasks for evaluation.", + "bbox": [ + 75, + 575, + 468, + 696 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 709, + 207, + 724 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We pre-train MRM on two multimodal datasets involving retinal images with genetics, and pathology images with genetics, respectively. To evaluate the quality of the representations learned on retinal images, we transfer the pre-trained model to four downstream retinal image-based tasks. As for the model pre-trained on pathology images, we assess it on a downstream pathology image-based task. The gene-image association analysis is performed to study the relation between images and genetics towards disease diagnosis. Finally, we extend our method to image pre-training to verify the effectiveness on single modality.", + "bbox": [ + 75, + 734, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Experimental Setup", + "text_level": 1, + "bbox": [ + 500, + 304, + 689, + 320 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1.1 Retinal Images with Genetics", + "text_level": 1, + "bbox": [ + 500, + 328, + 756, + 343 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Pre-training. We use UKB [33] to conduct the self-supervised pre-training, which is one of the largest multimodal images and genetics datasets. Following the previous work ContIG [34], we leverage the retinal fundus dataset as the pre-training set, which contains 155,238 images, and the genetics including 155,238 Raw-SNP samples, 145,206 PGS samples and 93,216 burden scores.", + "bbox": [ + 496, + 352, + 890, + 458 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Downstream Transfer. We introduce four tasks to evaluate and compare the effectiveness of the model pre-training.", + "bbox": [ + 498, + 459, + 890, + 489 + ], + "page_idx": 5 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1) Diabetic Retinopathy Detection (APTOS). The APTOS [1] is a fundus disease dataset including 35,126 2D images across five categories. All images are resized as $224 \\times 224$ for efficient fine-tuning. We split $80\\%$ as the training set to fine-tune the pre-trained MRM model, and the remaining $20\\%$ as the test set is used to evaluate the performance. The Quadratic Weighted Kappa (QwKappa) [14] is adopted as the metric to measure the agreement between the prediction and ground truth.", + "2) Retinal Fundus Disease Classification (RFMiD). The Retinal Fundus Multi-disease Image Dataset (RFMiD) [29] consists of 3200 annotated retinal fundus images of 46 eye diseases. RFMiD formulates a multi-label classification task since the images may contain multiple conditions. We split $80\\%$ as the training set and $20\\%$ as the test set. The area under the ROC curve (ROC-AUC) is used as the metric to evaluate the classification results.", + "3) Pathological Myopia Segmentation (PALM). The PALM dataset [18] contains 1200 images with disc and atrophy segmentation annotations. We use 800 images as the training split and 400 images as test split. The dice score is adopted as the segmentation evaluation metric.", + "4) Cardiovascular Risk Prediction (CRP). The retinal fundus images of UKB dataset can also be utilized to CRP including age, sex, smoking status, systolic and diastolic blood pressure (SBP, DBP), and body mass index (BMI) [31], formulating a regression with classification" + ], + "bbox": [ + 496, + 489, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "21457", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/90866f42c3601d428b777a63c2b39498faedb168a7fb7a88a36cf92a44c08af7.jpg", + "table_caption": [ + "Table 2. Transfer results on downstream pathological image task." + ], + "table_footnote": [], + "table_body": "
MethodGG
Acc ↑ROC-AUC ↑
Training from scratch (baseline)73.8390.16
Contrastive-based Pre-training
SimCLR [9]74.2490.62
MoCo v3 [11]74.7890.90
ContIG [34]75.1491.25
MIM-based Pre-Training
MAE [16]73.7590.44
SimMIM [43]73.9690.80
MultiMAE [3]74.4591.03
mc-BEI T [25]74.8291.35
AttMask [19]75.3691.75
MRM76.1792.07
", + "bbox": [ + 99, + 102, + 447, + 252 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "task. We use mean squared error (MSE) as the metric for numerical factors, i.e., age, BMI, SBP, DBP, and the ROC-AUC for the categorical factors, i.e., sex and smoking status.", + "bbox": [ + 75, + 277, + 470, + 325 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.1.2 Pathology Images with Genetics", + "text_level": 1, + "bbox": [ + 76, + 342, + 354, + 357 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Pre-training. We use TCGA-GBM with TCGA-LGG dataset [37] to conduct the pre-training, which consists of 736 paired samples of pathology slides and genetic profiles. We resize the curated pathology slides with the shape of $224 \\times 224$ as inputs. Considering each patient has multiple curated slides, we select one of them associated with one genetic profile as an input pair.", + "bbox": [ + 75, + 364, + 468, + 470 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Downstream Transfer. We leverage glioma grading (GG) to evaluate performance. The GG can improve the treatment planning for accurate determination. The TCGA dataset contains WHO grading labels including grade II, III and IV. We fine-tune the pre-trained model on training set with $80\\%$ data split and evaluate the performance on $20\\%$ data split. The accuracy and ROC-AUC are employed as the metrics to measure the classification results.", + "bbox": [ + 75, + 472, + 468, + 592 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.2. Implementation Details", + "text_level": 1, + "bbox": [ + 76, + 602, + 294, + 618 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Following prior works [16, 44], we adopt ViT-base as the image encoder and SNN network as the genome encoder to learn representations. The ViT and SNN models are trained via AdamW [26] and Adam [21], respectively, both with an initial learning rate of $1 \\times 10^{-3}$ . We use PyTorch [30] to implement our models, and train all models for 50 epochs with the batch size of 256 for UKB and 8 for TCGA. In relation matching, for efficiency, we randomly select 8 pair of multimodal features to perform matching constraint for two datasets. All comparisons [8, 11, 34, 16, 43, 3, 13, 25, 19] share the same settings to achieve a fair comparison. The balanced coefficient $\\lambda$ in Eq. (14) is set as 1.0, and the masking ratios $\\tau_{I}, \\tau_{G}$ for images and genetics are equal to $75\\%$ and $50\\%$ , respectively.", + "bbox": [ + 75, + 625, + 468, + 838 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Comparison with State-of-the-arts", + "text_level": 1, + "bbox": [ + 76, + 847, + 377, + 863 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In this section, to assess the quality of feature representations to various downstream tasks, we fine-tune the encoder", + "bbox": [ + 76, + 869, + 468, + 898 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/d16cf3e3ef8fa718a0823e32ebf9d016b8a523ed41f53a1e0e62b8b302c99388.jpg", + "table_caption": [ + "Table 3. Ablation study of each proposed component in relation masking and relation matching on retinal image-based tasks." + ], + "table_footnote": [], + "table_body": "
MaskingMatchingAPTOSRFMiDPALMCRP
RM selfRM crossL selfL crossQwKappaROC-AUC↑ Dice-Score↑ MSE↓ ROC-AUC ↑
83.6590.4972.513.49661.57
✓86.3793.4875.293.35267.21
✓85.1092.7174.203.41864.82
✓✓87.5094.2877.233.28370.52
✓✓✓88.2794.9478.493.21673.73
✓✓✓88.6595.5179.773.16274.27
✓✓✓✓89.8396.3181.453.10775.90
", + "bbox": [ + 501, + 114, + 890, + 233 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "with an initial task-relevant head together on the training set, and evaluate the downstream tasks on the test set.", + "bbox": [ + 496, + 258, + 890, + 289 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Retinal Images with Genetics. We compare MRM pretrained on UKB with state-of-the-art methods [8, 11, 34, 16, 43, 3, 13, 25, 19] on four downstream retinal image-based tasks in Table 1. MRM achieves $89.83\\%$ , $96.31\\%$ , $81.45\\%$ , $3.107$ and $75.90\\%$ scores on APTOS, RFMiD, PALM and CRP tasks, respectively, outperforming other comparisons by a clear margin in all tasks including disease classification, segmentation and regression. Particularly, compared with MIM-based pre-training methods, MRM is superior over the second best one AttMask [19] with $2.10\\%$ , $1.40\\%$ , $2.86\\%$ , $0.155$ and $6.50\\%$ scores on four tasks. These results reflect that masking out relation and retaining intact information within the input can obtain better feature representation than MIM-based input masking and per-sample reconstruction strategies for medical data.", + "bbox": [ + 496, + 290, + 892, + 516 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Pathology Images with Genetics. To verify the versatility of the proposed framework, we pre-train MRM on pathology image-genome dataset TCGA and fine-tune the model on downstream grade grading task to evaluate the transfer results. From Table 2, compared with other pretraining methods, MRM yields state-of-the-art performance with $76.17\\%$ accuracy and $92.07\\%$ ROC-AUC scores, indicating its effectiveness and flexibility on various types of medical images. Hence, the proposed MRM is able to achieve significantly better self-supervised leaning.", + "bbox": [ + 496, + 517, + 890, + 669 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4. Ablation Study", + "text_level": 1, + "bbox": [ + 500, + 679, + 653, + 695 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We ablate the effectiveness of each component in MRM on retinal image dataset.", + "bbox": [ + 496, + 703, + 890, + 733 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Effectiveness of relation masking. We study the effectiveness of the proposed self- and cross-modality relation masking. We start from a baseline that trains the autoencoder to construct the multimodal data, we first mask out a portion of self-modality relation in both image and genome branches. From Table 3, the self-modality relation masking brings performance gains by $2.72\\%$ , $2.99\\%$ , $2.78\\%$ , 0.144 and $5.64\\%$ scores on APTOS, RFMiD, PALM and CRP tasks, respectively. Then, we further mask out the cross-modality relation, the results show consistent increases by $1.13\\%$ , $0.80\\%$ , $1.94\\%$ , 0.069 and $3.31\\%$ on four tasks. To", + "bbox": [ + 496, + 734, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "21458", + "bbox": [ + 478, + 944, + 519, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c2600edaefb30c5cc0d50ca9aa1b2a6a193202d993f1c363225df85f7836040f.jpg", + "image_caption": [ + "Figure 3. Comparison of reconstruction results of different methods. From left to right suggests the original input and the reconstructed images by MAE [16], AttMask [19] and our MRM. We can observe that MRM can preserve the disease regions framed in blue while MIM-based methods lose them." + ], + "image_footnote": [], + "bbox": [ + 107, + 92, + 460, + 289 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "qualitatively verify the impact of the relation masking, we visualize the reconstruction images of different methods. Figure 3 illustrates that MIM-based approaches [16, 19] lose the tiny disease regions, while MRM can reconstruct almost complete disease regions. These advantages indicate that our relation masking in self- and cross-modality levels can preserve the disease semantics thereby improving the quality of the feature representation.", + "bbox": [ + 75, + 397, + 467, + 517 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Impact of relation matching. To observe the impact of the self- and cross-modality relation matching, on the top of the model with relation masking, we employ the self-modality matching constraint. As implied in Table 3, self-modality matching leads to the transfer result improvements by $0.77\\%$ , $0.66\\%$ , $1.26\\%$ , $0.067$ and $3.21\\%$ scores on APTOS, RFMiD, PALM and CRP tasks, respectively. When adding the cross-modality relation matching, the performance continuously grows by $1.56\\%$ , $1.37\\%$ , $2.96\\%$ , $0.109$ and $2.17\\%$ scores on four downstream tasks. The results illustrate that both self- and cross-modality relation matching can boost the representation learning, and they can render complementary constraints to achieve sample relation invariant when masking the feature relation.", + "bbox": [ + 75, + 520, + 467, + 731 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Masking ratios. To understand the influence of masking ratios $\\tau_{I}$ and $\\tau_{G}$ for images and genetics, we fine-tune the pre-trained model on diabetic retinopathy detection task under different masking ratios. Firstly, we mask the self- and cross-modality relation for image features with different ratio $\\tau_{I}$ including $10\\%$ , $25\\%$ , $50\\%$ , $75\\%$ and $90\\%$ . From Figure 4 (a), the best choice for $\\tau_{I}$ is $75\\%$ , and the performance decreases when diminishing or enlarging the ratio. As the ratio reduces from $75\\%$ to $10\\%$ , the transfer result drops remarkably by $1.35\\%$ . Moreover, we analyze the effect of masking ratio $\\tau_{G}$ for genetics and find that $50\\%$ is good for", + "bbox": [ + 75, + 734, + 467, + 900 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/74264b881bb2b0105b2c71aacb91d2023bd90bab1df5734caef50fc2a3362c77.jpg", + "image_caption": [ + "(a)" + ], + "image_footnote": [], + "bbox": [ + 504, + 90, + 694, + 189 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/5ee7566523083381042acc921d1265e0b945a30d9f01a514cd68739cc522d6da.jpg", + "image_caption": [ + "(b)", + "Figure 4. Ablation study. (a) Masking ratios $\\tau_{I}$ and $\\tau_{G}$ for image and genome. (b) Balanced coefficient $\\lambda$ of two loss functions." + ], + "image_footnote": [], + "bbox": [ + 705, + 90, + 885, + 189 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/530756ddeb49d3fb3826a1bbd32e1f43d0ec0dbaa41dc09b4338aab44f82b1bc.jpg", + "table_caption": [ + "Table 4. Results of gene-image association analysis." + ], + "table_footnote": [], + "table_body": "
MethodFound Regions ↑
Training from scratch4
SimCLR [9]5
MoCo v3 [11]6
ContIG [34]10
MAE [16]8
SimMIM [43]10
MultiMAE [3]13
mc-BEI T [25]14
AttMask [19]16
MRM18
", + "bbox": [ + 540, + 258, + 852, + 378 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "representation learning and transfer results.", + "bbox": [ + 500, + 406, + 785, + 420 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Loss balanced coefficient $\\lambda$ . We study the sensitivity of MRM towards the balanced coefficients $\\lambda$ for controlling two loss functions $\\mathcal{L}_{\\mathrm{recon}}$ and $\\mathcal{L}_{\\mathrm{match}}$ in Eq. (14), as shown in Figure 4 (b). It can be observed that the performance rises with the balanced coefficients $\\lambda$ increasing from 0.1 to 1.0, while it plunges when $\\lambda$ is larger than 1.0. These suggest that the proposed relation matching leads to beneficial representation learning with the appropriate range of $\\lambda$ , either too strong or too weak of the relation matching constraint damage the quality of the feature representation.", + "bbox": [ + 496, + 421, + 890, + 571 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.5. Gene-image Association Analysis", + "text_level": 1, + "bbox": [ + 500, + 584, + 789, + 599 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "To obtain an interpretable understanding on how genetics can improve images representation learning, we conduct gene-image association analysis for all models. This association analysis is a statistical tool for finding individual genetic regions correlated with image features according to the disease traits. The better the image representation, the more associated regions are expected to be discovered. Table 4 shows the number of independent regions each model finds, where we observe that MRM finds the most disease-related regions from genetics, explaining why genetics can improve image representation learning in our model.", + "bbox": [ + 496, + 608, + 890, + 773 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.6. Extension to Single Modality Pre-training", + "text_level": 1, + "bbox": [ + 500, + 785, + 856, + 801 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "To study the application of the proposed MRM on single modality, we pre-train MRM using merely image modality on retinal dataset from UKB, and evaluate the feature representation on downstream tasks. Specifically, during the pre-training phase, we remove the cross-modality attention layers and adopt self-attention with self-modality relation", + "bbox": [ + 496, + 809, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "21459", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/155718fbf34ee7ecd61f934f28928e73fbb4a77ab30fddc6bc696a78e05f7af4.jpg", + "table_caption": [ + "Table 5. Transfer results with single image modality pre-training on retinal image-based tasks." + ], + "table_footnote": [], + "table_body": "
MethodAPTOSRFMiDPALMCRP
QwKappa ↑ROC-AUC ↑Dice-Score ↑MSE ↓ROC-AUC ↑
Training from scratch79.2689.2777.583.44653.56
SimCLR [8]81.4390.5172.523.45359.25
MoCo v3 [17]82.2091.8273.973.43761.73
ContIG [34]82.8991.5579.173.30667.40
MAE [16]78.3188.6273.053.50360.32
SimMIM [43]79.9189.4771.393.46861.09
MultiMAE [3]80.5590.9174.523.42762.14
mc-BEI T [25]82.5991.7875.843.38863.61
AttMask [19]83.8092.3676.503.28564.77
MRM85.4693.1180.263.24570.15
", + "bbox": [ + 78, + 114, + 470, + 253 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "masking to capture the representation. The image feature is directly fed into the image decoder to reconstruct the image without multimodal fusion. As for the relation matching, only self-modality matching is employed for image features. Table 5 indicates that MRM exhibits the best transfer ability across four downstream tasks, verifying the effectiveness of MRM with single image modality pre-training.", + "bbox": [ + 75, + 277, + 468, + 383 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Broader Impact and Limitations", + "text_level": 1, + "bbox": [ + 76, + 395, + 375, + 412 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "The proposed MRM framework, consisting of relation masking and relation matching, can enable the model to capture relation information by token-wise feature masking and sample-wise global relation constraint, thereby learning better feature representation. Extensive experiments across various downstream diagnosis tasks demonstrate that the MRM has superior transfer ability over state-of-the-art methods, and it can also applies single image modality pretraining to achieve compelling performance. Moreover, in this work, we assume the data distribution between downstream datasets and the pre-training dataset is identical, and do not consider the issue of data domain shift. Hence, in future work, we will improve our framework towards data domain shift issue between pre-training dataset and various downstream datasets.", + "bbox": [ + 75, + 420, + 470, + 647 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 659, + 194, + 674 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this work, we present MRM framework to jointly leverage medical images and genetics for self-supervised pre-training. Instead of explicitly masking inputs, we design the relation masking to mask out feature relation and enable the model to capture informative patterns, which can retain intact disease-related semantics. Moreover, to enrich semantic relation, we present relation matching by exploiting inter-sample relation to encourage global constraints in the feature space. Extensive experiments verify the effectiveness of MRM on various downstream diagnosis tasks.", + "bbox": [ + 75, + 684, + 468, + 835 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 847, + 173, + 863 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Aptos 2019 blindness detection.", + "https://www.kaggle.com/c/" + ], + "bbox": [ + 84, + 872, + 467, + 898 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "aptos2019-blindnessdetection/ Accessed: 2021-11-04.6", + "[2] Shekoofeh Azizi, Basil Mustafa, Fiona Ryan, Zachary Beaver, Jan Freyberg, Jonathan Deaton, Aaron Loh, Alan Karthikesalingam, Simon Kornblith, Ting Chen, et al. Big self-supervised models advance medical image classification. In Proc. ICCV, pages 3478-3488, 2021. 3", + "[3] Roman Bachmann, David Mizrahi, Andrei Atanov, and Amir Zamir. Multimae: Multi-modal multi-task masked autoencoders. In Proc. ECCV, pages 348-367. Springer, 2022. 2, 3, 6, 7, 8, 9", + "[4] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. Beit: Bert pre-training of image transformers. In Proc. ICLR, 2022. 1, 2, 3", + "[5] Rodrigo Bonazzola, Nishant Ravikumar, Rahman Attar, Enzo Ferrante, Tanveer Syeda-Mahmood, and Alejandro F Frangi. Image-derived phenotype extraction for genetic discovery via unsupervised deep learning in cmr images. In Proc. MICCAI, pages 699-708. Springer, 2021. 1, 2, 3", + "[6] Nathaniel Braman, Jacob WH Gordon, Emery T Goossens, Caleb Willis, Martin C Stumpe, and Jagadish Venkataraman. Deep orthogonal fusion: multimodal prognostic biomarker discovery integrating radiology, pathology, genomic, and clinical data. In Proc. MICCAI, pages 667-677. Springer, 2021. 1, 3", + "[7] Richard J Chen, Ming Y Lu, Jingwen Wang, Drew FK Williamson, Scott J Rodig, Neal I Lindeman, and Faisal Mahmood. Pathomic fusion: an integrated framework for fusing histopathology and genomic features for cancer diagnosis and prognosis. IEEE TMI, 41(4):757-770, 2020. 2, 3", + "[8] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning of visual representations. In ICML, 2020. 2, 3, 6, 7, 9", + "[9] Ting Chen, Simon Kornblith, Kevin Swersky, Mohammad Norouzi, and Geoffrey Hinton. Big self-supervised models are strong semi-supervised learners. In NeurlPS, 2020. 2, 7, 8", + "[10] Xiaokang Chen, Mingyu Ding, Xiaodi Wang, Ying Xin, Shentong Mo, Yunhao Wang, Shumin Han, Ping Luo, Gang Zeng, and Jingdong Wang. Context autoencoder for self-supervised representation learning. arXiv preprint arXiv:2202.03026, 2022. 2, 3", + "[11] Xinlei Chen, Saining Xie, and Kaiming He. An empirical study of training self-supervised vision transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 9640-9649, 2021. 2, 7, 8", + "[12] Zekai Chen, Devansh Agarwal, Kshitij Aggarwal, Wiem Safta, Mariann Micsinai Balan, and Kevin Brown. Masked image modeling advances 3d medical image analysis. In Proc. WACV, 2023. 1", + "[13] Zhihong Chen, Yuhao Du, Jinpeng Hu, Yang Liu, Guanbin Li, Xiang Wan, and Tsung-Hui Chang. Multi-modal masked autoencoders for medical vision-and-language pre-training. In Proc. MICCAI, pages 679-689. Springer, 2022. 1, 3, 6, 7", + "[14] Jacob Cohen. Weighted kappa: nominal scale agreement provision for scaled disagreement or partial credit. *Psychol Bull*, 70(4):213, 1968. 6" + ], + "bbox": [ + 501, + 92, + 893, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "21460", + "bbox": [ + 478, + 944, + 519, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[15] Jean-Bastien Grill, Florian Strub, Florent Altché, Corentin Tallec, Pierre H Richemond, Elena Buchatskaya, Carl Doersch, Bernardo Avila Pires, Zhaohan Daniel Guo, Mohammad Gheshlaghi Azar, et al. Bootstrap your own latent: A new approach to self-supervised learning. In NeurIPS, 2020. 2, 3", + "[16] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dólár, and Ross Girshick. Masked autoencoders are scalable vision learners. In Proc. CVPR, pages 16000-16009, 2022. 1, 2, 3, 6, 7, 8, 9", + "[17] Kaiming He, Haoqi Fan, Yuxin Wu, Saining Xie, and Ross Girshick. Momentum contrast for unsupervised visual representation learning. In CVPR, 2020. 2, 3, 6, 9", + "[18] Jose Ignacio Orlando Hrvoje Bogunovic Xu Sun Jingan Liao Yanwu Xu Shaochong Zhang Huazhu Fu, Fei Li and Xiulan Zhang. Palm: Pathologic myopia challenge. 2019. 6", + "[19] Ioannis Kakogeorgiou, Spyros Gidaris, Bill Psomas, Yannis Avrithis, Andrei Bursuc, Konstantinos Karantzalos, and Nikos Komodakis. What to hide from your students: Attention-guided masked image modeling. In Proc. ECCV, pages 300-318. Springer, 2022. 2, 3, 6, 7, 8, 9", + "[20] Jacob Devlin Ming-Wei Chang Kenton and Lee Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In Proc. NAACL, pages 4171–4186, 2019. 3", + "[21] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. Proc. ICLR, 2015. 7", + "[22] Günter Klambauer, Thomas Unterthiner, Andreas Mayr, and Sepp Hochreiter. Self-normalizing neural networks. In Proc. NeurIPS, volume 30, 2017. 4", + "[23] Wuyang Li, Jie Liu, Bo Han, and Yixuan Yuan. Adjustment and alignment for unbiased open set domain adaptation. In Proc. CVPR, pages 24110-24119, 2023. 2", + "[24] Wuyang Li, Xinyu Liu, and Yixuan Yuan. Sigma: Semantic-complete graph matching for domain adaptive object detection. In Proc. CVPR, pages 5291-5300, 2022. 2", + "[25] Xiaotong Li, Yixiao Ge, Kun Yi, Zixuan Hu, Ying Shan, and Ling-Yu Duan. mc-beit: Multi-choice discretization for image bert pre-training. In Proc. ECCV, pages 231-246. Springer, 2022. 1, 2, 6, 7, 8, 9", + "[26] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. Proc. ICLR, 2019. 7", + "[27] Yang Luo, Zhineng Chen, and Xieping Gao. Self-distillation augmented masked autoencoders for histopathological image classification. arXiv preprint arXiv:2203.16983, 2022. 1, 3", + "[28] Zhenyuan Ning, Denghui Du, Chao Tu, Qianjin Feng, and Yu Zhang. Relation-aware shared representation learning for cancer prognosis analysis with auxiliary clinical variables and incomplete multi-modality data. IEEE TMI, 41(1):186-198, 2021. 1, 2, 3", + "[29] Samiksha Pachade, Prasanna Porwal, Dhanshree Thulkar, Manesh Kokare, Girish Deshmukh, Vivek Sahasrabuddhe, Luca Giancardo, Gwenolé Quellec, and Fabrice Mériaudeau. Retinal fundus multi-disease image dataset (rfmid): A dataset for multi-disease detection research. Data, 6(2):14, 2021. 6" + ], + "bbox": [ + 78, + 90, + 470, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[30] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, Luca Antiga, et al. Pytorch: An imperative style, high-performance deep learning library. In NeurIPS, 2019. 7", + "[31] Ryan Poplin, Avinash V Varadarajan, Katy Blumer, Yun Liu, Michael V McConnell, Greg S Corrado, Lily Peng, and Dale R Webster. Prediction of cardiovascular risk factors from retinal fundus photographs via deep learning. Nat. Biomed. Eng., 2(3):158-164, 2018. 6", + "[32] Yu Rong, Wenbing Huang, Tingyang Xu, and Junzhou Huang. Droppedge: Towards deep graph convolutional networks on node classification. In Proc. ICLR, 2020. 5", + "[33] Hannah Spitzer, Kai Kiwitz, Katrin Amunts, Stefan Harmeling, and Timo Dickscheid. Improving cytoarchitectonic segmentation of human brain areas with self-supervised siamese networks. In Proc. MICCAI, pages 663-671. Springer, 2018. 6", + "[34] Aiham Taleb, Matthias Kirchler, Remo Monti, and Christoph Lippert. Contig: Self-supervised multimodal contrastive learning for medical imaging with genetics. In Proc. CVPR, pages 20908-20921, 2022. 1, 3, 6, 7, 8, 9", + "[35] Aiham Taleb, Christoph Lippert, Tassilo Klein, and Moin Nabi. Multimodal self-supervised learning for medical image analysis. In Proc. IPMI, pages 661-673. Springer, 2021. 1, 3", + "[36] Aiham Taleb, Winfried Loetzsch, Noel Danz, Julius Severin, Thomas Gaertner, Benjamin Bergner, and Christoph Lippert. 3d self-supervised methods for medical imaging. Proc. NeurIPS, 33:18158-18172, 2020. 1, 3", + "[37] Katarzyna Tomczak, Patrycja Czerwińska, and Maciej Wiznerowicz. Review the cancer genome atlas (tcga): an immeasurable source of knowledge. Contemp. Oncol., 2015(1):68-77, 2015. 7", + "[38] Rami S Vanguri, Jia Luo, Andrew T Aukerman, Jacklynn V Egger, Christopher J Fong, Nataly Horvat, Andrew Pagano, Jose de Arimateia Batista Araujo-Filho, Luke Geneslaw, Hira Rizvi, et al. Multimodal integration of radiology, pathology and genomics for prediction of response to pd-(l) 1 blockade in patients with non-small cell lung cancer. Nature cancer, 3(10):1151-1164, 2022. 1, 3", + "[39] Wenguan Wang, Tianfei Zhou, Fisher Yu, Jifeng Dai, Ender Konukoglu, and Luc Van Gool. Exploring cross-image pixel contrast for semantic segmentation. In Proc. ICCV, pages 7303-7313, 2021. 2", + "[40] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In Proc. CVPR, pages 14668-14678, 2022. 2", + "[41] LI Wuyang, YANG Chen, LIU Jie, LIU Xinyu, GUO Xiaqing, and YUAN Yixuan. Joint polyp detection and segmentation with heterogeneous endoscopic data. In Proc. ISBI Workshop, pages 69-79. CEUR-WS Team, 2021. 1", + "[42] Junfei Xiao, Yutong Bai, Alan Yuille, and Zongwei Zhou. Delving into masked autoencoders for multi-label thorax disease classification. In Proc. WACV, pages 3588-3600, 2023. 1, 3" + ], + "bbox": [ + 501, + 92, + 892, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "21461", + "bbox": [ + 478, + 945, + 517, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[43] Zhenda Xie, Zheng Zhang, Yue Cao, Yutong Lin, Jianmin Bao, Zhuliang Yao, Qi Dai, and Han Hu. Simmim: A simple framework for masked image modeling. In Proc. CVPR, pages 9653-9663, 2022. 1, 2, 3, 6, 7, 8, 9", + "[44] Xiaohan Xing, Zhen Chen, Meilu Zhu, Yuenan Hou, Zhifan Gao, and Yixuan Yuan. Discrepancy and gradient-guided multi-modal knowledge distillation for pathological glioma grading. In Proc. MICCAI, pages 636-646. Springer, 2022. 1, 3, 7", + "[45] Qiushi Yang, Xiaqing Guo, Zhen Chen, Peter YM Woo, and Yixuan Yuan. D2-net: Dual disentanglement network for brain tumor segmentation with missing modalities. IEEE TMI, 41(10):2953-2964, 2022. 1", + "[46] Qiushi Yang and Yixuan Yuan. Learning dynamic convolutions for multi-modal 3d mri brain tumor segmentation. In Brainlesion: MICCAI Workshop, pages 441-451. Springer, 2021. 1", + "[47] Zhuoning Yuan, Yan Yan, Milan Sonka, and Tianbao Yang. Large-scale robust deep auc maximization: A new surrogate loss and empirical studies on medical image classification. In Proc. ICCV, pages 3040-3049, 2021. 1", + "[48] Jinghao Zhou, Chen Wei, Huiyu Wang, Wei Shen, Cihang Xie, Alan Yuille, and Tao Kong. Image bert pre-training with online tokenizer. In Proc. ICLR, 2022. 2, 3", + "[49] Lei Zhou, Huidong Liu, Joseph Bae, Junjun He, Dimitris Samaras, and Prateek Prasanna. Self pre-training with masked autoencoders for medical image analysis. arXiv preprint arXiv:2203.05573, 2022. 1, 3" + ], + "bbox": [ + 78, + 90, + 468, + 486 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "21462", + "bbox": [ + 478, + 945, + 517, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/3ca9548a-636d-4952-80cd-106e032bd384_model.json b/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/3ca9548a-636d-4952-80cd-106e032bd384_model.json new file mode 100644 index 0000000000000000000000000000000000000000..86fb56896ad3cc4288fff157a777724a9d9504ba --- /dev/null +++ b/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/3ca9548a-636d-4952-80cd-106e032bd384_model.json @@ -0,0 +1,2444 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.131, + 0.895, + 0.155 + ], + "angle": 0, + "content": "MRM: Masked Relation Modeling for Medical Image Pre-Training with Genetics" + }, + { + "type": "text", + "bbox": [ + 0.227, + 0.18, + 0.338, + 0.2 + ], + "angle": 0, + "content": "Qiushi Yang" + }, + { + "type": "text", + "bbox": [ + 0.373, + 0.181, + 0.471, + 0.199 + ], + "angle": 0, + "content": "Wuyang Li" + }, + { + "type": "text", + "bbox": [ + 0.513, + 0.181, + 0.597, + 0.199 + ], + "angle": 0, + "content": "Baopu Li3" + }, + { + "type": "text", + "bbox": [ + 0.638, + 0.181, + 0.767, + 0.198 + ], + "angle": 0, + "content": "Yixuan Yuan\\(^{1,2*}\\)" + }, + { + "type": "text", + "bbox": [ + 0.198, + 0.201, + 0.792, + 0.217 + ], + "angle": 0, + "content": "\\(^{1}\\)City University of Hong Kong \\(^{2}\\)The Chinese University of Hong Kong \\(^{3}\\)Independent Researcher" + }, + { + "type": "text", + "bbox": [ + 0.09, + 0.22, + 0.451, + 0.234 + ], + "angle": 0, + "content": "{qsyang2-c, wuyangli2-c}@my.cityu.edu.hk." + }, + { + "type": "text", + "bbox": [ + 0.509, + 0.22, + 0.682, + 0.234 + ], + "angle": 0, + "content": "bpliu.cuhk@gmail.com" + }, + { + "type": "text", + "bbox": [ + 0.713, + 0.221, + 0.901, + 0.234 + ], + "angle": 0, + "content": "yxyuan@ee.cuhk.edu.hk" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.269, + 0.314, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.301, + 0.474, + 0.725 + ], + "angle": 0, + "content": "Modern deep learning techniques on automatic multimodal medical diagnosis rely on massive expert annotations, which is time-consuming and prohibitive. Recent masked image modeling (MIM)-based pre-training methods have witnessed impressive advances for learning meaningful representations from unlabeled data and transferring to downstream tasks. However, these methods focus on natural images and ignore the specific properties of medical data, yielding unsatisfying generalization performance on downstream medical diagnosis. In this paper, we aim to leverage genetics to boost image pre-training and present a masked relation modeling (MRM) framework. Instead of explicitly masking input data in previous MIM methods leading to loss of disease-related semantics, we design relation masking to mask out token-wise feature relation in both self- and cross-modality levels, which preserves intact semantics within the input and allows the model to learn rich disease-related information. Moreover, to enhance semantic relation modeling, we propose relation matching to align the sample-wise relation between the intact and masked features. The relation matching exploits inter-sample relation by encouraging global constraints in the feature space to render sufficient semantic relation for feature representation. Extensive experiments demonstrate that the proposed framework is simple yet powerful, achieving state-of-the-art transfer performance on various downstream diagnosis tasks. Codes are available at https://github.com/CityU-AIM-Group/MRM." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.754, + 0.21, + 0.77 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.47, + 0.842 + ], + "angle": 0, + "content": "In the medical diagnosis [44, 34, 38, 28, 6, 5], the largescale multimodal biobank data, e.g., images and genetics, is necessary for a reliable diagnosis, overcoming the limited scale and disease information of a single-modality" + }, + { + "type": "image", + "bbox": [ + 0.507, + 0.275, + 0.699, + 0.357 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.699, + 0.277, + 0.888, + 0.357 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.359, + 0.699, + 0.444 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.699, + 0.36, + 0.888, + 0.444 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.457, + 0.895, + 0.61 + ], + "angle": 0, + "content": "Figure 1. Comparison of different masking strategies on natural and medical data. (a): Existing MIM methods mask out input natural images and infer the missing content to learn semantic representations via reconstruction task. (b): Recent pre-training approaches for disease diagnosis explicitly employ MIM on input medical data (e.g., medical images and genome), whilst they are prone to lose tiny disease regions and cause non-tractable reconstruction. (c): Our method masks token-wise feature relation across multimodal data and matches sample-wise relation between the intact and masked features, preserving intact semantic regions and enriching relation information." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.641, + 0.895, + 0.734 + ], + "angle": 0, + "content": "dataset. However, the prohibitive expert annotations of large-scale datasets make it difficult to train a conventional deep model [44, 45, 41, 46, 47]. Particularly, in this multimodal scenario, the requirements of the experts in various medical fields prevent enough annotation access, severely limiting the grounding of the automatic diagnosis system." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.896, + 0.902 + ], + "angle": 0, + "content": "To address this, the most prospering trend [16, 43, 4, 34, 13, 35, 36, 12, 27] is self-supervised pre-training, e.g., masked image modeling (MIM) [16, 43, 13, 42], aiming to train a label-free model with adequate generalization capacity. Existing MIM methods [16, 43, 4, 25, 13, 42, 49] mask out a high portion of patches within input images and infer the missing content, as suggested in Figure 1 (a). They make use of contextual information to glance the semantics and reconstruct the entire images, which performs a mask-and-reconstruct task to pre-train the model without annotation and transfer meaningful representations to various" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.852, + 0.223, + 0.864 + ], + "angle": 0, + "content": "*Corresponding author." + }, + { + "type": "page_footnote", + "bbox": [ + 0.078, + 0.864, + 0.47, + 0.901 + ], + "angle": 0, + "content": "This work was supported by Hong Kong Research Grants Council (RGC) General Research Fund 14220622, 14204321, and Innovation and Technology Commission-Innovation and Technology Fund ITS/100/20." + }, + { + "type": "list", + "bbox": [ + 0.078, + 0.852, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "21452" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.467, + 0.106 + ], + "angle": 0, + "content": "downstream tasks for improving label-efficient fine-tuning." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.111, + 0.47, + 0.533 + ], + "angle": 0, + "content": "Though achieving great success, most works [16, 43, 4, 40, 10, 25, 19] are designed for natural images, ignoring the essential differences between medical data and natural images. Therefore, we empirically find that existing MIM CANNOT works well in medical data (see Table 1), and even totally fails to reconstruct diseases (see Figure 3). The reasons derive from a critical observation regarding the significant data differences, which can be summarized into two challenges. Firstly, compared with natural images, there are limited semantic regions in medical data. As shown in Figure 1 (a), the semantic-rich foreground is always the main body of the natural image, while the rest non-informative background region only represents a minority part. Differently, in the medical image (Figure 1 (b)), the majority of regions are backgrounds, and the informative disease regions are usually on a tiny scale. Under the strategy of masking entire tokens in existing MIM methods [16, 43, 4, 40, 10, 25, 19], if the disease tokens are masked out, the disease-related semantic is totally missing with a catastrophic information loss, leading to a nontractable reconstruction. This issue also exists between genomics and natural images. The semantic regions in genomics, i.e., the disease-related patterns, mainly lie in a minority of genome segments [28, 5, 7]. Hence, instead of masking the whole input token, these observations motivate us to delve into the masking of token-level relation, which preserves abundant semantic discriminability and adequate self-supervision, as illustrated in Figure 1 (c) Left." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.536, + 0.47, + 0.838 + ], + "angle": 0, + "content": "The second challenge is the limited semantic relation. In a natural image, the background and foreground relationship, e.g., the bird in the sky and the person in a room, tends to be prosperous and abundant, serving a critical role in semantic-level learning [39, 24]. In contrast, in each medical data sample, the disease-aware relation is limited and insufficient to provide enough discriminative evidence. The reason lies in that the medical datasets are usually collected from the same human organ, e.g., the fundus, containing redundant and similar anatomical patterns, e.g., the capillary, which severely prevent the relation modeling between the disease and the complex medical scene. This challenge hampers reliable relation learning in existing MIM methods, and may incur an inevitable overfitting to noninformative relation within the background [40, 25, 23, 3]. Hence, considering the limited semantic relation in each data sample, we are committed to going beyond the self-supervised learning for an independent and individual data sample, and propose to encourage global constraints for exploiting inter-sample relation (see Figure 1 (c) Right)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.47, + 0.901 + ], + "angle": 0, + "content": "To combat above challenges, as shown in Figure 1 (c), we present MRM, a masked relation modeling from a unified view of relation, containing relation masking and relation matching, to rationally pre-train multimodal medical" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.422 + ], + "angle": 0, + "content": "images with genetics. To preserve intact semantic information within raw input, we devise relation masking strategy to allow the model to learn disease-related semantics. Instead of masking out input data, the relation masking investigates token-wise relation within feature representations in both self- and cross-modality levels and masks out the relation among all multimodal tokens. The relation masking endows the model to explicitly learn global dependency from raw data without missing disease-related semantic information. Furthermore, to improve the semantic relation modeling, the relation matching is designed to provide global constraint by aligning the feature relation across multiple samples. Specifically, relation matching exploits sample-wise relation in both self- and cross-modality levels to encourage the relation consistency between the intact and masked features. This enjoys the complementary advantages of persample pixel-wise reconstruction loss and boosts the transfer ability of the model. With the pre-trained model, we can obtain the feature representation that can be transferred to supervised downstream diagnosis tasks for boosting label-efficient fine-tuning, alleviating the severe demand for specialized annotations." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.425, + 0.848, + 0.44 + ], + "angle": 0, + "content": "In summary, our contributions fall into four parts:" + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.452, + 0.892, + 0.512 + ], + "angle": 0, + "content": "- We identify the challenges of current MIM methods on medical data, and present MRM, a masked relation modeling using multimodal medical data to facilitate image representation learning." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.525, + 0.892, + 0.616 + ], + "angle": 0, + "content": "- Towards the issue of limited semantic regions in medical data, we design relation masking to mask tokenwise feature relation across self- and cross-modality. Different from MIM explicitly masking inputs, relation masking preserves disease semantics within inputs, endowing a powerful mask-and-construct task." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.63, + 0.892, + 0.705 + ], + "angle": 0, + "content": "- Moreover, to enrich the semantic relation among diseases, the relation matching is proposed to capture abundant disease-related relation by aligning sample-wise feature relation between intact and masked features in both self- and cross-modality levels." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.718, + 0.892, + 0.779 + ], + "angle": 0, + "content": "- Extensive transfer evaluation on various downstream tasks using two public medical pre-training datasets demonstrate that our framework performs superior transfer ability over state-of-the-art methods." + }, + { + "type": "list", + "bbox": [ + 0.519, + 0.452, + 0.892, + 0.779 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.806, + 0.642, + 0.822 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.832, + 0.685, + 0.848 + ], + "angle": 0, + "content": "2.1. Visual Pre-training" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "In recent years, self-supervised visual pre-training [8, 9, 15, 17, 11, 16, 43, 48, 4] has achieved exceptional transfer performance in various downstream visual tasks, which" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "21453" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.096, + 0.887, + 0.332 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.351, + 0.893, + 0.381 + ], + "angle": 0, + "content": "Figure 2. Overview of masked relation modeling (MRM). MRM contains relation masking to mask out token-wise feature relation with preserving disease-related semantics, and the relation matching to enforce sample-wise relation consistency for global semantic modeling." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.405, + 0.473, + 0.707 + ], + "angle": 0, + "content": "can be divided into two categories. The first is contrastive-based methods [8, 15, 17, 35, 35] that aim to project similar samples nearby while pull dissimilar ones far away in the feature space. For instance, SimCLR [8] imposes two embeddings from a sample under different views consistency via InfoNCE loss, and BYOL [15] merely pushes the positive pairs together with a momentum encoder for boosting transfer performance. Moreover, inspired by the progress of masked language modeling on natural language processing [20], masked image modeling (MIM)-based approaches [16, 48, 43, 4, 3, 10, 3] are proposed to pre-train visual models and exhibit remarkable transfer performance. MAE [16] formulates a pixel-wise reconstruction task to mask out a high portion of input patches and infer the masked ones with visible tokens via an autoencoder. Afterwards, many followups [43, 3, 19, 10] devise MIM models to improve the representation learning. However, they mainly focus on natural images and ignore the essential differences between the medical data and natural images, thereby delivering unsatisfying transfer results [27, 49]." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.724, + 0.373, + 0.741 + ], + "angle": 0, + "content": "2.2. Medical Self-supervised Learning" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Most works [35, 36, 2, 34] on medical self-supervised learning extend the ideas of contrastive learning and develop customized strategies to pre-train models. 3DSSL [36] adopt a series of proxy tasks to present a 3D versions self-supervised model and achieves compelling transfer results. ContIG [34] crafts a multimodal pre-training framework using image and genome data via contrastive learning and delivers competitive transfer ability. Although efficiency, these contrastive-based approaches strongly rely on well-defined data augmentations to construct positive" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.405, + 0.892, + 0.602 + ], + "angle": 0, + "content": "pairs, which are difficult for medical data, especially for structured data, e.g., genetics. Most recently, some studies [13, 42, 27, 49] adopt MIM to self-supervised pre-train medical models. MedicalMAE [49] introduces a self pretraining paradigm by employing MAE [16] to pre-train the model and achieve superior performance. To perform multimodal pre-training, \\(\\mathrm{M}^{3}\\mathrm{3AE}\\) [13] randomly masks out the tokens of image and language inputs and aims to infer the whole data using visible tokens. All of them still adopt input masking strategy, which may incur tiny disease-related region missing and non-tractable reconstruction. Differently, we design a novel relation masking strategy in the feature space and retain intact disease-related information." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.63, + 0.813, + 0.646 + ], + "angle": 0, + "content": "2.3. Learning from Images and Genetics" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.66, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Genetics can provide comprehensive information for many disease diagnosis and treatment planning [38, 28, 6, 5, 7], which attract much attention from researchers. Many works [44, 34, 38] formulate a multimodal learning task by jointly leveraging genetics and medical images to exploit complementary knowledge. Considering that the genetics may be difficult to acquire in many clinical applications, recent studies [34, 7] aim to design pre-training models using images and genetics for improving practical image-based diagnosis. However, they merely use contrastive constraint to perform self-supervised learning, while they fail to adopt the efficient mask-and-reconstruct task to pre-train models. In this work, we aim to leverage genetics with images to boost the visual representation learning via semantic relation modeling, which discovers both inner-sample and intersample relation to achieve more effective pre-training." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.957 + ], + "angle": 0, + "content": "21454" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.09, + 0.33, + 0.108 + ], + "angle": 0, + "content": "3. Masked Relation Modeling" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.115, + 0.47, + 0.206 + ], + "angle": 0, + "content": "In this section, we start by introducing the preliminaries of vision Transformer and masked image modeling. We then present the masked relation modeling (MRM), containing relation masking and relation matching. The overall pre-training and transfer inference of the framework are described at the end of the section." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.215, + 0.218, + 0.23 + ], + "angle": 0, + "content": "3.1. Preliminaries" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.238, + 0.471, + 0.389 + ], + "angle": 0, + "content": "Vision Transformer (ViT). Given an image \\( x \\in \\mathbb{R}^{c \\times h \\times w} \\), ViT first splits it into \\( n = hw / p^2 \\) non-overlapping patches \\( x_P = \\{x_1; x_2; \\ldots; x_n\\} \\), \\( x_i \\in \\mathbb{R}^{c \\times p \\times p} \\), where \\( p \\times p \\) denotes the size of each patch. Afterwards, the patches \\( x_P \\) are tokenized as a sequence of token embeddings \\( e = \\{e_1; e_2; \\ldots; e_n\\} \\), \\( e_i \\in \\mathbb{R}^{1 \\times d} \\), where \\( d \\) is the dimension of each token, via a linear projection with positional embeddings. The embeddings \\( e \\) are then processed by a cascade of multi-head self-attention layers to capture global information, where the self-attention is described as follow:" + }, + { + "type": "equation", + "bbox": [ + 0.145, + 0.398, + 0.47, + 0.43 + ], + "angle": 0, + "content": "\\[\n\\operatorname {A t t e n t i o n} (e) = \\operatorname {S o f t m a x} \\left(\\frac {1}{\\sqrt {d}} Q K ^ {T}\\right) V, \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.439, + 0.47, + 0.53 + ], + "angle": 0, + "content": "where \\(K = eW^{K}\\), \\(Q = eW^{Q}\\), \\(V = eW^{V}\\), \\(K, Q, V \\in \\mathbb{R}^{1 \\times d}\\) is the key, query and value obtained by the linear projection via \\(W^{K}, W^{Q}, W^{V}\\), respectively. Each layer of the ViT encoder contains a multi-head self-attention block, and the feature representation is produced by multiple layers within the encoder." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.531, + 0.47, + 0.668 + ], + "angle": 0, + "content": "Masked Image Modeling (MIM). The input patches \\( x_{p} \\) are randomly masked out with a high ratio, denoted as masked patches \\( x_{M} \\). The remaining visible patches \\( x_{V} \\) are fed into ViT encoder \\( f(\\cdot) \\) to capture features \\( z = f(x_{V}) \\), which are then sent to a lightweight decoder \\( h(\\cdot) \\) to recover the missing patches \\( \\hat{x} = h(z) \\) of the input data. The overall framework is optimized by mean-squared error (MSE) reconstruction loss function \\( \\mathcal{L}_{\\mathrm{MIM}} \\) between the recovered patches \\( \\hat{x} \\) and masked patches \\( x_{M} \\) as:" + }, + { + "type": "equation", + "bbox": [ + 0.167, + 0.677, + 0.469, + 0.695 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {M I M}} = \\mathbb {E} | | x _ {M} - h (f (x _ {V})) | | _ {2} ^ {2}. \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.704, + 0.471, + 0.904 + ], + "angle": 0, + "content": "Overview of Masked Relation Modeling (MRM). As illustrated in Figure 2, the proposed MRM consists of the relation masking strategy to mask out feature relation and preserve intact disease-related semantics, and the relation matching to offer global constraints for relation modeling. With the input image \\( x_{I} \\) and genome \\( x_{G} \\), the ViT encoder \\( f_{I} \\) and self-normalizing network (SNN) [22] \\( f_{G} \\) produces masked feature representations \\( z_{I,M},z_{G,M} \\) for image and genome via relation masking. Parallely, the intact representations \\( z_{I},z_{G} \\) are obtained by two encoders without relation masking. Afterwards, the masked features \\( z_{I,M},z_{G,M} \\) are aggregated with the intact features \\( z_{G},z_{I} \\) from the other modality to yield the fused features \\( z_{I}^{F},z_{G}^{F} \\), respectively." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.168 + ], + "angle": 0, + "content": "These fused feature are then put into the image decoder \\( h_I \\) and the genome decoder \\( h_G \\) to reconstruct original data \\( \\hat{x}_I \\) and \\( \\hat{x}_G \\). The relation matching is employed on intact and masked feature representations with the data reconstruction loss to jointly optimize the overall framework." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.174, + 0.673, + 0.19 + ], + "angle": 0, + "content": "3.2. Relation Masking" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.197, + 0.892, + 0.348 + ], + "angle": 0, + "content": "Due to the medical data usually appearing tiny disease patterns, current input-level masking strategies may discard disease-related semantics and hardly learn informative feature representation. To address this problem, the relation masking is proposed to mask token-wise feature relation from self- and cross-modality perspectives in a cascading manner, which can maintain intact input disease-related information during pre-training. The operations of relation masking for image and genome are parallel, for brevity, we adopt the image branch to introduce." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.348, + 0.892, + 0.44 + ], + "angle": 0, + "content": "Self-modality relation masking. In the \\(i\\)-th relation masking block, given \\(z_{I}^{0}\\) as the input image token, we first calculate \\(K_{I}^{S}, Q_{I}^{S}, V_{I}^{S}\\) as its key, query and value, respectively. Then, the normalized feature dependency in tokens is obtained by computing the relation between the key \\(K_{I}^{S}\\) and query \\(Q_{I}^{S}\\) of the image feature as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.578, + 0.445, + 0.892, + 0.477 + ], + "angle": 0, + "content": "\\[\nR _ {\\text {s e l f}} = \\operatorname {S o f t m a x} \\left(\\frac {1}{\\sqrt {d}} Q _ {I} ^ {S} \\cdot \\left(K _ {I} ^ {S}\\right) ^ {T}\\right). \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.48, + 0.892, + 0.617 + ], + "angle": 0, + "content": "This self-modality relation \\( R_{\\mathrm{self}} \\) reflects the token-wise semantic correspondence within the image feature. The tokens with stronger relation contain more interactive and informative semantics. To enable the model to capture intramodality feature representation via the reconstruction task, on the top of self-modality relation, we aim to break the strong dependency across informative regions by relation masking. Specifically, we mask out high-intensity elements with a ratio \\( \\tau_I \\) in self-modality relation:" + }, + { + "type": "equation", + "bbox": [ + 0.525, + 0.621, + 0.892, + 0.655 + ], + "angle": 0, + "content": "\\[\nR _ {\\text {s e l f}} ^ {M} [ p, q ] = \\left\\{ \\begin{array}{c c} R _ {\\text {s e l f}} [ p, q ] & \\text {i f} R _ {\\text {s e l f}} [ p, q ] < r _ {\\text {s e l f}} ^ {p} \\\\ 0 & \\text {e l s e ,} \\end{array} \\right. \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.659, + 0.892, + 0.84 + ], + "angle": 0, + "content": "where \\( r_{\\mathrm{self}}^p \\) refers to the intensity of the top-\\( \\tau_I \\) element among the \\( p \\)-th row of the self-modality relation \\( R_{\\mathrm{self}} \\) matrix. Note that the masked elements are selected in each row of the self-modality relation matrix to remove the semantic correspondence for all tokens with the same intensity. Afterwards, the masked relation matrix \\( R_{\\mathrm{self}}^M \\) is forwarded to produce the token \\( z_I^S = R_{\\mathrm{self}}^M V_I^S \\) for subsequent data flow. With the self-modality relation masking, the relative important dependency within the modality is discarded and we enforce the model to reconstruct the original image with the remaining weak feature relation. Thus, the model can capture disease-related feature representation of images." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Cross-modality relation masking. In an attempt to incorporate multimodal knowledge, after the self-modality self-attention layer, we perform cross-modality attention between the image and genome features. Precisely, obtained" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "21455" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.091, + 0.47, + 0.152 + ], + "angle": 0, + "content": "the image and genome tokens \\(z_{I}^{S},z_{G}^{S}\\) masked via selfmodality relation masking, we compute token-wise crossmodality relation to capture semantic correspondence between image and genome features:" + }, + { + "type": "equation", + "bbox": [ + 0.15, + 0.164, + 0.47, + 0.197 + ], + "angle": 0, + "content": "\\[\nR _ {\\text {c r o s s}} = \\operatorname {S o f t m a x} \\left(\\frac {1}{\\sqrt {d}} Q _ {I} ^ {C} \\cdot \\left(K _ {G} ^ {C}\\right) ^ {T}\\right), \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.209, + 0.471, + 0.359 + ], + "angle": 0, + "content": "where \\( K_{G}^{C} \\) means the key of genome feature \\( z_{G}^{S} \\), and \\( Q_{I}^{C} \\) represents the query of image feature \\( z_{I}^{S} \\) in the cross-attention layer. This cross-modality attention can amalgamate two modality knowledge and improve the feature representation towards disease-related information. Then, to allow the model to learn complementary multimodal knowledge and the relation between two modalities, we perform cross-modality relation masking by removing strong semantic correspondence between image and genome features:" + }, + { + "type": "equation", + "bbox": [ + 0.088, + 0.371, + 0.469, + 0.405 + ], + "angle": 0, + "content": "\\[\nR _ {\\text {c r o s s}} ^ {M} [ p, q ] = \\left\\{ \\begin{array}{c l} R _ {\\text {c r o s s}} [ p, q ] & \\text {i f} R _ {\\text {c r o s s}} [ p, q ] < r _ {\\text {c r o s s}} ^ {p} \\\\ 0 & \\text {e l s e ,} \\end{array} \\right. \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.417, + 0.469, + 0.493 + ], + "angle": 0, + "content": "where \\(r_{\\mathrm{cross}}^p\\) denotes the intensity of the top-\\(\\tau_I\\) element among the \\(p\\)-th row of the cross-modality relation matrix \\(R_{\\mathrm{cross}}\\). With the masked relation \\(R_{\\mathrm{cross}}^M\\), we can obtain the fused image token \\(z_I^C = R_{\\mathrm{cross}}^M V_G^C\\), where \\(V_G^C\\) means the value of the genome feature." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.494, + 0.47, + 0.722 + ], + "angle": 0, + "content": "Reconstruction with relation masking. We feed the input data into two networks shared parameters, where the first network consists of a ViT encoder to yield intact image feature \\( z_{I} \\) and a SNN encoder with self-attention blocks to produce genome feature \\( z_{G} \\). Parallely, the second network employs the proposed self- and cross-modality relation masking in first two attention blocks to generate masked features \\( z_{I,M}, z_{G,M} \\) for image and genome, respectively. Afterwards, the masked features are incorporated with the intact feature from the other modality and produce amalgamated features \\( z_{I}^{F} = \\text{concat}[z_{I,M}; z_{G}] \\), \\( z_{G}^{F} = \\text{concat}[z_{G,M}; z_{I}] \\) for images and genome. The fused features are then put into the decoders \\( h_{I}(\\cdot), h_{G}(\\cdot) \\) to reconstruct image and genome \\( \\hat{x}_{I} = h_{I}(z_{I}^{F}), \\hat{x}_{G} = h_{G}(z_{G}^{F}) \\). The overall loss function for the reconstruction of image and genome is:" + }, + { + "type": "equation", + "bbox": [ + 0.105, + 0.733, + 0.469, + 0.753 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {r e c o n}} = \\left\\| h _ {I} \\left(z _ {I} ^ {F}\\right) - x _ {I} \\right\\| _ {2} ^ {2} + \\left\\| h _ {G} \\left(z _ {G} ^ {F}\\right) - x _ {G} \\right\\| _ {2} ^ {2}. \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.469, + 0.901 + ], + "angle": 0, + "content": "The relation masking strategy exploits the token-wise feature relation for mask-and-reconstruct task. It is worth noting that although the strong relation is removed, the intrinsic information within the data is retained [32]. Therefore, with the original complete image and genome as inputs, our relation masking can preserve the intact disease-related semantics. With the relation masking-based reconstruction task, the self-modality relation is encouraged to be recovered by the model to capture disease-related information" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.152 + ], + "angle": 0, + "content": "within each modality, and the cross-modality relation is enforced to reconstruct to learn abundant multimodal knowledge to improve the disease-related representation for effective downstream diagnosis tasks transfer." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.161, + 0.681, + 0.177 + ], + "angle": 0, + "content": "3.3. Relation Matching" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.184, + 0.892, + 0.274 + ], + "angle": 0, + "content": "Considering that the disease-aware relation among diseases is limited in medical data, to provide sufficient semantic relation, we propose relation matching, a global constraint to align the sample-wise relation across self- and cross-modality samples to perform global constraints in the feature space." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.275, + 0.892, + 0.38 + ], + "angle": 0, + "content": "Self-modality matching. Assume one minibatch contains \\(B\\) multimodal pairs \\(\\{x_I^i,x_G^i\\}_{i = 1}^B\\), we can obtain the intact feature representations \\(\\{z_I^i,z_G^i\\}_{i = 1}^B\\) and masked ones \\(\\{z_{I,M}^{i},z_{G,M}^{i}\\}_{i = 1}^{B}\\) via the proposed relation masking strategy. Firstly, we compute the sample-wise relation \\(\\{R_{\\mathrm{II}}^{i,j}\\}_{i,j = 1}^{B},\\{R_{\\mathrm{GG}}^{i,j}\\}_{i,j = 1}^{B}\\) across all intact features of image and genome, respectively:" + }, + { + "type": "equation", + "bbox": [ + 0.627, + 0.389, + 0.891, + 0.416 + ], + "angle": 0, + "content": "\\[\nR _ {\\mathrm {I I}} ^ {i, j} = \\operatorname {s i m} \\left(z _ {I} ^ {i}; z _ {I} ^ {j}\\right) \\tag {8}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.627, + 0.411, + 0.766, + 0.43 + ], + "angle": 0, + "content": "\\[\nR _ {\\mathrm {G G}} ^ {i, j} = \\operatorname {s i m} \\left(z _ {G} ^ {i}; z _ {G} ^ {j}\\right),\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.439, + 0.892, + 0.484 + ], + "angle": 0, + "content": "where \\(\\mathrm{sim}(\\cdot ;\\cdot)\\) denotes the similarity between two features, here we adopt the cosine similarity. Similarly, we acquire the sample relation among masked features:" + }, + { + "type": "equation", + "bbox": [ + 0.61, + 0.493, + 0.891, + 0.52 + ], + "angle": 0, + "content": "\\[\nR _ {\\mathrm {I I}, \\mathrm {M}} ^ {i, j} = \\operatorname {s i m} \\left(z _ {I, M} ^ {i}; z _ {I, M} ^ {j}\\right), \\tag {9}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.604, + 0.516, + 0.79, + 0.535 + ], + "angle": 0, + "content": "\\[\nR _ {\\mathrm {G G}, \\mathrm {M}} ^ {i, j} = \\operatorname {s i m} (z _ {G, M} ^ {i}; z _ {G, M} ^ {j}).\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.543, + 0.892, + 0.589 + ], + "angle": 0, + "content": "We aim to ensure the relation consistency between intact and masked features. The matching objective for self-modality feature relation can be formulated as:" + }, + { + "type": "equation", + "bbox": [ + 0.5, + 0.598, + 0.891, + 0.653 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {s e l f}} = \\frac {1}{2 B ^ {2}} \\sum_ {i = 1} ^ {B} \\sum_ {j = 1} ^ {B} \\left| \\left| R _ {\\mathrm {I I}} ^ {i, j} - R _ {\\mathrm {I I}, \\mathrm {M}} ^ {i, j} \\right| \\right| _ {2} ^ {2} + \\left| \\left| R _ {\\mathrm {G G}} ^ {i, j} - R _ {\\mathrm {G G}, \\mathrm {M}} ^ {i, j} \\right| \\right| _ {2} ^ {2}. \\tag {10}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.654, + 0.892, + 0.7 + ], + "angle": 0, + "content": "Cross-modality matching. Furthermore, to incorporate multimodal information and bridge the gap of different modalities, we compute the cross-modality relation:" + }, + { + "type": "equation", + "bbox": [ + 0.616, + 0.708, + 0.891, + 0.735 + ], + "angle": 0, + "content": "\\[\nR _ {\\mathrm {I G}} ^ {i, j} = \\operatorname {s i m} \\left(z _ {I} ^ {i}; z _ {G} ^ {j}\\right), \\tag {11}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.608, + 0.731, + 0.786, + 0.75 + ], + "angle": 0, + "content": "\\[\nR _ {\\mathrm {I G , M}} ^ {i, j} = \\mathrm {s i m} (z _ {I, M} ^ {i}; z _ {G, M} ^ {j}),\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.759, + 0.892, + 0.853 + ], + "angle": 0, + "content": "where \\(\\{R_{\\mathrm{IG}}^{i,j}\\}_{i,j = 1}^{B}\\) represents the cross-modality relation across intact multimodal features, and \\(\\{R_{\\mathrm{IG,M}}^{i,j}\\}_{i,j = 1}^{B}\\) means the relation across masked ones. We intend to ensure the cross-modality relation to be invariant between masked and intact features. The cross-modality feature relation can be calculated as:" + }, + { + "type": "equation", + "bbox": [ + 0.567, + 0.861, + 0.891, + 0.904 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {c r o s s}} = \\frac {1}{B ^ {2}} \\sum_ {i = 1} ^ {B} \\sum_ {j = 1} ^ {B} \\left| \\left| R _ {\\mathrm {I G}} ^ {i, j} - R _ {\\mathrm {I G}, \\mathrm {M}} ^ {i, j} \\right| \\right| _ {2} ^ {2}. \\tag {12}\n\\]" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "21456" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.088, + 0.89, + 0.102 + ], + "angle": 0, + "content": "Table 1. Comparison with state-of-the-art pre-training algorithms via fine-tuning evaluation on four downstream retinal image-based tasks." + }, + { + "type": "table", + "bbox": [ + 0.085, + 0.102, + 0.887, + 0.281 + ], + "angle": 0, + "content": "
MethodMasking LevelAPTOSRFMiDPALMCRP
InputRelationQwKappa ↑ROC-AUC ↑Dice-Score ↑MSE ↓ROC-AUC ↑
Training from scratch (baseline)--83.2592.9179.443.40558.05
Contrastive-based Pre-training Methods
SimCLR [8]--84.5093.7573.183.42663.92
MoCo v3 [17]--85.0394.0275.733.42165.33
ContIG [34]--86.2794.5980.253.18473.57
MIM-based Pre-Training Methods
MAE [16]✓✗84.0692.7174.283.48864.29
SimMIM [43]✓✗84.6793.8072.733.45066.08
MultiMAE [3]✓✗85.5994.2675.923.41167.51
M3AE [13]✓✗86.8594.7277.353.39468.39
mc-BEiT [25]✓✗87.1594.3777.403.37266.38
AttMask [19]✓✗87.7394.9178.593.26269.40
MRM✗✓89.8396.3181.453.10775.90
" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.305, + 0.47, + 0.336 + ], + "angle": 0, + "content": "With the self- and cross-modality feature relation, we can formulate the overall relation matching objective as:" + }, + { + "type": "equation", + "bbox": [ + 0.195, + 0.343, + 0.469, + 0.358 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {m a t c h}} = \\mathcal {L} _ {\\text {s e l f}} + \\mathcal {L} _ {\\text {c r o s s}}. \\tag {13}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.365, + 0.469, + 0.426 + ], + "angle": 0, + "content": "The relation matching encourages global constraints in the feature space to provide sufficient semantic relation, which enjoys the complementary advantages of pixel-wise data reconstruction loss in Eq. (7)." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.433, + 0.389, + 0.449 + ], + "angle": 0, + "content": "3.4. Pre-training and Transfer Inference" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.457, + 0.469, + 0.546 + ], + "angle": 0, + "content": "In the pre-training phase, the image and genome as multimodal inputs are fed into the model. We adopt the proposed relation masking to generate masked features, and employ the relation matching as the global constraint with the data reconstruction loss to jointly optimize the overall framework:" + }, + { + "type": "equation", + "bbox": [ + 0.182, + 0.554, + 0.469, + 0.57 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {o v e r a l l}} = \\mathcal {L} _ {\\text {r e c o n}} + \\lambda \\mathcal {L} _ {\\text {m a t c h}}, \\tag {14}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.577, + 0.469, + 0.697 + ], + "angle": 0, + "content": "where \\(\\lambda\\) denotes the balanced coefficient to control contributions of the reconstruction task and the relation matching. During the phase of downstream image-based fine-tuning, we discard the genome branch and utilize the image encoder to extract the feature representation without relation masking. The pre-trained encoder following a randomly initial task-relevant head is fine-tuned on downstream tasks for evaluation." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.71, + 0.209, + 0.726 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.469, + 0.901 + ], + "angle": 0, + "content": "We pre-train MRM on two multimodal datasets involving retinal images with genetics, and pathology images with genetics, respectively. To evaluate the quality of the representations learned on retinal images, we transfer the pre-trained model to four downstream retinal image-based tasks. As for the model pre-trained on pathology images, we assess it on a downstream pathology image-based task. The gene-image association analysis is performed to study the relation between images and genetics towards disease diagnosis. Finally, we extend our method to image pre-training to verify the effectiveness on single modality." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.305, + 0.691, + 0.321 + ], + "angle": 0, + "content": "4.1. Experimental Setup" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.329, + 0.757, + 0.344 + ], + "angle": 0, + "content": "4.1.1 Retinal Images with Genetics" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.353, + 0.892, + 0.459 + ], + "angle": 0, + "content": "Pre-training. We use UKB [33] to conduct the self-supervised pre-training, which is one of the largest multimodal images and genetics datasets. Following the previous work ContIG [34], we leverage the retinal fundus dataset as the pre-training set, which contains 155,238 images, and the genetics including 155,238 Raw-SNP samples, 145,206 PGS samples and 93,216 burden scores." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.46, + 0.892, + 0.49 + ], + "angle": 0, + "content": "Downstream Transfer. We introduce four tasks to evaluate and compare the effectiveness of the model pre-training." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.491, + 0.892, + 0.627 + ], + "angle": 0, + "content": "1) Diabetic Retinopathy Detection (APTOS). The APTOS [1] is a fundus disease dataset including 35,126 2D images across five categories. All images are resized as \\(224 \\times 224\\) for efficient fine-tuning. We split \\(80\\%\\) as the training set to fine-tune the pre-trained MRM model, and the remaining \\(20\\%\\) as the test set is used to evaluate the performance. The Quadratic Weighted Kappa (QwKappa) [14] is adopted as the metric to measure the agreement between the prediction and ground truth." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.628, + 0.892, + 0.747 + ], + "angle": 0, + "content": "2) Retinal Fundus Disease Classification (RFMiD). The Retinal Fundus Multi-disease Image Dataset (RFMiD) [29] consists of 3200 annotated retinal fundus images of 46 eye diseases. RFMiD formulates a multi-label classification task since the images may contain multiple conditions. We split \\(80\\%\\) as the training set and \\(20\\%\\) as the test set. The area under the ROC curve (ROC-AUC) is used as the metric to evaluate the classification results." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.749, + 0.892, + 0.824 + ], + "angle": 0, + "content": "3) Pathological Myopia Segmentation (PALM). The PALM dataset [18] contains 1200 images with disc and atrophy segmentation annotations. We use 800 images as the training split and 400 images as test split. The dice score is adopted as the segmentation evaluation metric." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "4) Cardiovascular Risk Prediction (CRP). The retinal fundus images of UKB dataset can also be utilized to CRP including age, sex, smoking status, systolic and diastolic blood pressure (SBP, DBP), and body mass index (BMI) [31], formulating a regression with classification" + }, + { + "type": "list", + "bbox": [ + 0.498, + 0.491, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "21457" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.088, + 0.465, + 0.102 + ], + "angle": 0, + "content": "Table 2. Transfer results on downstream pathological image task." + }, + { + "type": "table", + "bbox": [ + 0.1, + 0.103, + 0.449, + 0.253 + ], + "angle": 0, + "content": "
MethodGG
Acc ↑ROC-AUC ↑
Training from scratch (baseline)73.8390.16
Contrastive-based Pre-training
SimCLR [9]74.2490.62
MoCo v3 [11]74.7890.90
ContIG [34]75.1491.25
MIM-based Pre-Training
MAE [16]73.7590.44
SimMIM [43]73.9690.80
MultiMAE [3]74.4591.03
mc-BEI T [25]74.8291.35
AttMask [19]75.3691.75
MRM76.1792.07
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.278, + 0.471, + 0.326 + ], + "angle": 0, + "content": "task. We use mean squared error (MSE) as the metric for numerical factors, i.e., age, BMI, SBP, DBP, and the ROC-AUC for the categorical factors, i.e., sex and smoking status." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.343, + 0.355, + 0.358 + ], + "angle": 0, + "content": "4.1.2 Pathology Images with Genetics" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.366, + 0.47, + 0.472 + ], + "angle": 0, + "content": "Pre-training. We use TCGA-GBM with TCGA-LGG dataset [37] to conduct the pre-training, which consists of 736 paired samples of pathology slides and genetic profiles. We resize the curated pathology slides with the shape of \\(224 \\times 224\\) as inputs. Considering each patient has multiple curated slides, we select one of them associated with one genetic profile as an input pair." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.473, + 0.469, + 0.593 + ], + "angle": 0, + "content": "Downstream Transfer. We leverage glioma grading (GG) to evaluate performance. The GG can improve the treatment planning for accurate determination. The TCGA dataset contains WHO grading labels including grade II, III and IV. We fine-tune the pre-trained model on training set with \\(80\\%\\) data split and evaluate the performance on \\(20\\%\\) data split. The accuracy and ROC-AUC are employed as the metrics to measure the classification results." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.603, + 0.295, + 0.619 + ], + "angle": 0, + "content": "4.2. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.626, + 0.47, + 0.839 + ], + "angle": 0, + "content": "Following prior works [16, 44], we adopt ViT-base as the image encoder and SNN network as the genome encoder to learn representations. The ViT and SNN models are trained via AdamW [26] and Adam [21], respectively, both with an initial learning rate of \\(1 \\times 10^{-3}\\). We use PyTorch [30] to implement our models, and train all models for 50 epochs with the batch size of 256 for UKB and 8 for TCGA. In relation matching, for efficiency, we randomly select 8 pair of multimodal features to perform matching constraint for two datasets. All comparisons [8, 11, 34, 16, 43, 3, 13, 25, 19] share the same settings to achieve a fair comparison. The balanced coefficient \\(\\lambda\\) in Eq. (14) is set as 1.0, and the masking ratios \\(\\tau_{I}, \\tau_{G}\\) for images and genetics are equal to \\(75\\%\\) and \\(50\\%\\), respectively." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.848, + 0.379, + 0.864 + ], + "angle": 0, + "content": "4.3. Comparison with State-of-the-arts" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.47, + 0.9 + ], + "angle": 0, + "content": "In this section, to assess the quality of feature representations to various downstream tasks, we fine-tune the encoder" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.088, + 0.892, + 0.114 + ], + "angle": 0, + "content": "Table 3. Ablation study of each proposed component in relation masking and relation matching on retinal image-based tasks." + }, + { + "type": "table", + "bbox": [ + 0.502, + 0.115, + 0.892, + 0.234 + ], + "angle": 0, + "content": "
MaskingMatchingAPTOSRFMiDPALMCRP
RM selfRM crossL selfL crossQwKappaROC-AUC↑ Dice-Score↑ MSE↓ ROC-AUC ↑
83.6590.4972.513.49661.57
✓86.3793.4875.293.35267.21
✓85.1092.7174.203.41864.82
✓✓87.5094.2877.233.28370.52
✓✓✓88.2794.9478.493.21673.73
✓✓✓88.6595.5179.773.16274.27
✓✓✓✓89.8396.3181.453.10775.90
" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.26, + 0.892, + 0.29 + ], + "angle": 0, + "content": "with an initial task-relevant head together on the training set, and evaluate the downstream tasks on the test set." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.291, + 0.893, + 0.517 + ], + "angle": 0, + "content": "Retinal Images with Genetics. We compare MRM pretrained on UKB with state-of-the-art methods [8, 11, 34, 16, 43, 3, 13, 25, 19] on four downstream retinal image-based tasks in Table 1. MRM achieves \\(89.83\\%\\), \\(96.31\\%\\), \\(81.45\\%\\), \\(3.107\\) and \\(75.90\\%\\) scores on APTOS, RFMiD, PALM and CRP tasks, respectively, outperforming other comparisons by a clear margin in all tasks including disease classification, segmentation and regression. Particularly, compared with MIM-based pre-training methods, MRM is superior over the second best one AttMask [19] with \\(2.10\\%\\), \\(1.40\\%\\), \\(2.86\\%\\), \\(0.155\\) and \\(6.50\\%\\) scores on four tasks. These results reflect that masking out relation and retaining intact information within the input can obtain better feature representation than MIM-based input masking and per-sample reconstruction strategies for medical data." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.518, + 0.892, + 0.67 + ], + "angle": 0, + "content": "Pathology Images with Genetics. To verify the versatility of the proposed framework, we pre-train MRM on pathology image-genome dataset TCGA and fine-tune the model on downstream grade grading task to evaluate the transfer results. From Table 2, compared with other pretraining methods, MRM yields state-of-the-art performance with \\(76.17\\%\\) accuracy and \\(92.07\\%\\) ROC-AUC scores, indicating its effectiveness and flexibility on various types of medical images. Hence, the proposed MRM is able to achieve significantly better self-supervised leaning." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.68, + 0.654, + 0.696 + ], + "angle": 0, + "content": "4.4. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.704, + 0.891, + 0.734 + ], + "angle": 0, + "content": "We ablate the effectiveness of each component in MRM on retinal image dataset." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Effectiveness of relation masking. We study the effectiveness of the proposed self- and cross-modality relation masking. We start from a baseline that trains the autoencoder to construct the multimodal data, we first mask out a portion of self-modality relation in both image and genome branches. From Table 3, the self-modality relation masking brings performance gains by \\(2.72\\%\\), \\(2.99\\%\\), \\(2.78\\%\\), 0.144 and \\(5.64\\%\\) scores on APTOS, RFMiD, PALM and CRP tasks, respectively. Then, we further mask out the cross-modality relation, the results show consistent increases by \\(1.13\\%\\), \\(0.80\\%\\), \\(1.94\\%\\), 0.069 and \\(3.31\\%\\) on four tasks. To" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.957 + ], + "angle": 0, + "content": "21458" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.109, + 0.093, + 0.461, + 0.29 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.3, + 0.47, + 0.369 + ], + "angle": 0, + "content": "Figure 3. Comparison of reconstruction results of different methods. From left to right suggests the original input and the reconstructed images by MAE [16], AttMask [19] and our MRM. We can observe that MRM can preserve the disease regions framed in blue while MIM-based methods lose them." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.398, + 0.468, + 0.518 + ], + "angle": 0, + "content": "qualitatively verify the impact of the relation masking, we visualize the reconstruction images of different methods. Figure 3 illustrates that MIM-based approaches [16, 19] lose the tiny disease regions, while MRM can reconstruct almost complete disease regions. These advantages indicate that our relation masking in self- and cross-modality levels can preserve the disease semantics thereby improving the quality of the feature representation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.521, + 0.468, + 0.732 + ], + "angle": 0, + "content": "Impact of relation matching. To observe the impact of the self- and cross-modality relation matching, on the top of the model with relation masking, we employ the self-modality matching constraint. As implied in Table 3, self-modality matching leads to the transfer result improvements by \\(0.77\\%\\), \\(0.66\\%\\), \\(1.26\\%\\), \\(0.067\\) and \\(3.21\\%\\) scores on APTOS, RFMiD, PALM and CRP tasks, respectively. When adding the cross-modality relation matching, the performance continuously grows by \\(1.56\\%\\), \\(1.37\\%\\), \\(2.96\\%\\), \\(0.109\\) and \\(2.17\\%\\) scores on four downstream tasks. The results illustrate that both self- and cross-modality relation matching can boost the representation learning, and they can render complementary constraints to achieve sample relation invariant when masking the feature relation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Masking ratios. To understand the influence of masking ratios \\(\\tau_{I}\\) and \\(\\tau_{G}\\) for images and genetics, we fine-tune the pre-trained model on diabetic retinopathy detection task under different masking ratios. Firstly, we mask the self- and cross-modality relation for image features with different ratio \\(\\tau_{I}\\) including \\(10\\%\\), \\(25\\%\\), \\(50\\%\\), \\(75\\%\\) and \\(90\\%\\). From Figure 4 (a), the best choice for \\(\\tau_{I}\\) is \\(75\\%\\), and the performance decreases when diminishing or enlarging the ratio. As the ratio reduces from \\(75\\%\\) to \\(10\\%\\), the transfer result drops remarkably by \\(1.35\\%\\). Moreover, we analyze the effect of masking ratio \\(\\tau_{G}\\) for genetics and find that \\(50\\%\\) is good for" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.092, + 0.696, + 0.19 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.604, + 0.191, + 0.617, + 0.2 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "image", + "bbox": [ + 0.706, + 0.092, + 0.887, + 0.19 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.798, + 0.192, + 0.81, + 0.2 + ], + "angle": 0, + "content": "(b)" + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.205, + 0.892, + 0.233 + ], + "angle": 0, + "content": "Figure 4. Ablation study. (a) Masking ratios \\(\\tau_{I}\\) and \\(\\tau_{G}\\) for image and genome. (b) Balanced coefficient \\(\\lambda\\) of two loss functions." + }, + { + "type": "table_caption", + "bbox": [ + 0.541, + 0.246, + 0.85, + 0.259 + ], + "angle": 0, + "content": "Table 4. Results of gene-image association analysis." + }, + { + "type": "table", + "bbox": [ + 0.541, + 0.26, + 0.853, + 0.379 + ], + "angle": 0, + "content": "
MethodFound Regions ↑
Training from scratch4
SimCLR [9]5
MoCo v3 [11]6
ContIG [34]10
MAE [16]8
SimMIM [43]10
MultiMAE [3]13
mc-BEI T [25]14
AttMask [19]16
MRM18
" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.407, + 0.787, + 0.421 + ], + "angle": 0, + "content": "representation learning and transfer results." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.422, + 0.892, + 0.573 + ], + "angle": 0, + "content": "Loss balanced coefficient \\(\\lambda\\). We study the sensitivity of MRM towards the balanced coefficients \\(\\lambda\\) for controlling two loss functions \\(\\mathcal{L}_{\\mathrm{recon}}\\) and \\(\\mathcal{L}_{\\mathrm{match}}\\) in Eq. (14), as shown in Figure 4 (b). It can be observed that the performance rises with the balanced coefficients \\(\\lambda\\) increasing from 0.1 to 1.0, while it plunges when \\(\\lambda\\) is larger than 1.0. These suggest that the proposed relation matching leads to beneficial representation learning with the appropriate range of \\(\\lambda\\), either too strong or too weak of the relation matching constraint damage the quality of the feature representation." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.585, + 0.79, + 0.601 + ], + "angle": 0, + "content": "4.5. Gene-image Association Analysis" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.609, + 0.892, + 0.775 + ], + "angle": 0, + "content": "To obtain an interpretable understanding on how genetics can improve images representation learning, we conduct gene-image association analysis for all models. This association analysis is a statistical tool for finding individual genetic regions correlated with image features according to the disease traits. The better the image representation, the more associated regions are expected to be discovered. Table 4 shows the number of independent regions each model finds, where we observe that MRM finds the most disease-related regions from genetics, explaining why genetics can improve image representation learning in our model." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.786, + 0.857, + 0.803 + ], + "angle": 0, + "content": "4.6. Extension to Single Modality Pre-training" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.892, + 0.901 + ], + "angle": 0, + "content": "To study the application of the proposed MRM on single modality, we pre-train MRM using merely image modality on retinal dataset from UKB, and evaluate the feature representation on downstream tasks. Specifically, during the pre-training phase, we remove the cross-modality attention layers and adopt self-attention with self-modality relation" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "21459" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.088, + 0.47, + 0.114 + ], + "angle": 0, + "content": "Table 5. Transfer results with single image modality pre-training on retinal image-based tasks." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.115, + 0.472, + 0.255 + ], + "angle": 0, + "content": "
MethodAPTOSRFMiDPALMCRP
QwKappa ↑ROC-AUC ↑Dice-Score ↑MSE ↓ROC-AUC ↑
Training from scratch79.2689.2777.583.44653.56
SimCLR [8]81.4390.5172.523.45359.25
MoCo v3 [17]82.2091.8273.973.43761.73
ContIG [34]82.8991.5579.173.30667.40
MAE [16]78.3188.6273.053.50360.32
SimMIM [43]79.9189.4771.393.46861.09
MultiMAE [3]80.5590.9174.523.42762.14
mc-BEI T [25]82.5991.7875.843.38863.61
AttMask [19]83.8092.3676.503.28564.77
MRM85.4693.1180.263.24570.15
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.278, + 0.47, + 0.384 + ], + "angle": 0, + "content": "masking to capture the representation. The image feature is directly fed into the image decoder to reconstruct the image without multimodal fusion. As for the relation matching, only self-modality matching is employed for image features. Table 5 indicates that MRM exhibits the best transfer ability across four downstream tasks, verifying the effectiveness of MRM with single image modality pre-training." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.396, + 0.377, + 0.414 + ], + "angle": 0, + "content": "5. Broader Impact and Limitations" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.421, + 0.471, + 0.648 + ], + "angle": 0, + "content": "The proposed MRM framework, consisting of relation masking and relation matching, can enable the model to capture relation information by token-wise feature masking and sample-wise global relation constraint, thereby learning better feature representation. Extensive experiments across various downstream diagnosis tasks demonstrate that the MRM has superior transfer ability over state-of-the-art methods, and it can also applies single image modality pretraining to achieve compelling performance. Moreover, in this work, we assume the data distribution between downstream datasets and the pre-training dataset is identical, and do not consider the issue of data domain shift. Hence, in future work, we will improve our framework towards data domain shift issue between pre-training dataset and various downstream datasets." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.66, + 0.196, + 0.675 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.685, + 0.47, + 0.837 + ], + "angle": 0, + "content": "In this work, we present MRM framework to jointly leverage medical images and genetics for self-supervised pre-training. Instead of explicitly masking inputs, we design the relation masking to mask out feature relation and enable the model to capture informative patterns, which can retain intact disease-related semantics. Moreover, to enrich semantic relation, we present relation matching by exploiting inter-sample relation to encourage global constraints in the feature space. Extensive experiments verify the effectiveness of MRM on various downstream diagnosis tasks." + }, + { + "type": "title", + "bbox": [ + 0.08, + 0.848, + 0.174, + 0.864 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.085, + 0.873, + 0.468, + 0.887 + ], + "angle": 0, + "content": "[1] Aptos 2019 blindness detection." + }, + { + "type": "ref_text", + "bbox": [ + 0.112, + 0.888, + 0.335, + 0.9 + ], + "angle": 0, + "content": "https://www.kaggle.com/c/" + }, + { + "type": "list", + "bbox": [ + 0.085, + 0.873, + 0.468, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.119 + ], + "angle": 0, + "content": "aptos2019-blindnessdetection/ Accessed: 2021-11-04.6" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.121, + 0.894, + 0.189 + ], + "angle": 0, + "content": "[2] Shekoofeh Azizi, Basil Mustafa, Fiona Ryan, Zachary Beaver, Jan Freyberg, Jonathan Deaton, Aaron Loh, Alan Karthikesalingam, Simon Kornblith, Ting Chen, et al. Big self-supervised models advance medical image classification. In Proc. ICCV, pages 3478-3488, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.191, + 0.895, + 0.245 + ], + "angle": 0, + "content": "[3] Roman Bachmann, David Mizrahi, Andrei Atanov, and Amir Zamir. Multimae: Multi-modal multi-task masked autoencoders. In Proc. ECCV, pages 348-367. Springer, 2022. 2, 3, 6, 7, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.247, + 0.895, + 0.286 + ], + "angle": 0, + "content": "[4] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. Beit: Bert pre-training of image transformers. In Proc. ICLR, 2022. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.289, + 0.895, + 0.357 + ], + "angle": 0, + "content": "[5] Rodrigo Bonazzola, Nishant Ravikumar, Rahman Attar, Enzo Ferrante, Tanveer Syeda-Mahmood, and Alejandro F Frangi. Image-derived phenotype extraction for genetic discovery via unsupervised deep learning in cmr images. In Proc. MICCAI, pages 699-708. Springer, 2021. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.359, + 0.895, + 0.44 + ], + "angle": 0, + "content": "[6] Nathaniel Braman, Jacob WH Gordon, Emery T Goossens, Caleb Willis, Martin C Stumpe, and Jagadish Venkataraman. Deep orthogonal fusion: multimodal prognostic biomarker discovery integrating radiology, pathology, genomic, and clinical data. In Proc. MICCAI, pages 667-677. Springer, 2021. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.442, + 0.895, + 0.522 + ], + "angle": 0, + "content": "[7] Richard J Chen, Ming Y Lu, Jingwen Wang, Drew FK Williamson, Scott J Rodig, Neal I Lindeman, and Faisal Mahmood. Pathomic fusion: an integrated framework for fusing histopathology and genomic features for cancer diagnosis and prognosis. IEEE TMI, 41(4):757-770, 2020. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.525, + 0.895, + 0.566 + ], + "angle": 0, + "content": "[8] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning of visual representations. In ICML, 2020. 2, 3, 6, 7, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.567, + 0.895, + 0.62 + ], + "angle": 0, + "content": "[9] Ting Chen, Simon Kornblith, Kevin Swersky, Mohammad Norouzi, and Geoffrey Hinton. Big self-supervised models are strong semi-supervised learners. In NeurlPS, 2020. 2, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.623, + 0.894, + 0.691 + ], + "angle": 0, + "content": "[10] Xiaokang Chen, Mingyu Ding, Xiaodi Wang, Ying Xin, Shentong Mo, Yunhao Wang, Shumin Han, Ping Luo, Gang Zeng, and Jingdong Wang. Context autoencoder for self-supervised representation learning. arXiv preprint arXiv:2202.03026, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.692, + 0.894, + 0.748 + ], + "angle": 0, + "content": "[11] Xinlei Chen, Saining Xie, and Kaiming He. An empirical study of training self-supervised vision transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 9640-9649, 2021. 2, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.749, + 0.894, + 0.802 + ], + "angle": 0, + "content": "[12] Zekai Chen, Devansh Agarwal, Kshitij Aggarwal, Wiem Safta, Mariann Micsinai Balan, and Kevin Brown. Masked image modeling advances 3d medical image analysis. In Proc. WACV, 2023. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.804, + 0.894, + 0.859 + ], + "angle": 0, + "content": "[13] Zhihong Chen, Yuhao Du, Jinpeng Hu, Yang Liu, Guanbin Li, Xiang Wan, and Tsung-Hui Chang. Multi-modal masked autoencoders for medical vision-and-language pre-training. In Proc. MICCAI, pages 679-689. Springer, 2022. 1, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.86, + 0.894, + 0.9 + ], + "angle": 0, + "content": "[14] Jacob Cohen. Weighted kappa: nominal scale agreement provision for scaled disagreement or partial credit. *Psychol Bull*, 70(4):213, 1968. 6" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.895, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.957 + ], + "angle": 0, + "content": "21460" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.174 + ], + "angle": 0, + "content": "[15] Jean-Bastien Grill, Florian Strub, Florent Altché, Corentin Tallec, Pierre H Richemond, Elena Buchatskaya, Carl Doersch, Bernardo Avila Pires, Zhaohan Daniel Guo, Mohammad Gheshlaghi Azar, et al. Bootstrap your own latent: A new approach to self-supervised learning. In NeurIPS, 2020. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.178, + 0.472, + 0.233 + ], + "angle": 0, + "content": "[16] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dólár, and Ross Girshick. Masked autoencoders are scalable vision learners. In Proc. CVPR, pages 16000-16009, 2022. 1, 2, 3, 6, 7, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.234, + 0.472, + 0.276 + ], + "angle": 0, + "content": "[17] Kaiming He, Haoqi Fan, Yuxin Wu, Saining Xie, and Ross Girshick. Momentum contrast for unsupervised visual representation learning. In CVPR, 2020. 2, 3, 6, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.278, + 0.472, + 0.319 + ], + "angle": 0, + "content": "[18] Jose Ignacio Orlando Hrvoje Bogunovic Xu Sun Jingan Liao Yanwu Xu Shaochong Zhang Huazhu Fu, Fei Li and Xiulan Zhang. Palm: Pathologic myopia challenge. 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.321, + 0.472, + 0.389 + ], + "angle": 0, + "content": "[19] Ioannis Kakogeorgiou, Spyros Gidaris, Bill Psomas, Yannis Avrithis, Andrei Bursuc, Konstantinos Karantzalos, and Nikos Komodakis. What to hide from your students: Attention-guided masked image modeling. In Proc. ECCV, pages 300-318. Springer, 2022. 2, 3, 6, 7, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.391, + 0.472, + 0.445 + ], + "angle": 0, + "content": "[20] Jacob Devlin Ming-Wei Chang Kenton and Lee Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In Proc. NAACL, pages 4171–4186, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.447, + 0.472, + 0.474 + ], + "angle": 0, + "content": "[21] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. Proc. ICLR, 2015. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.476, + 0.472, + 0.517 + ], + "angle": 0, + "content": "[22] Günter Klambauer, Thomas Unterthiner, Andreas Mayr, and Sepp Hochreiter. Self-normalizing neural networks. In Proc. NeurIPS, volume 30, 2017. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.519, + 0.472, + 0.56 + ], + "angle": 0, + "content": "[23] Wuyang Li, Jie Liu, Bo Han, and Yixuan Yuan. Adjustment and alignment for unbiased open set domain adaptation. In Proc. CVPR, pages 24110-24119, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.562, + 0.472, + 0.604 + ], + "angle": 0, + "content": "[24] Wuyang Li, Xinyu Liu, and Yixuan Yuan. Sigma: Semantic-complete graph matching for domain adaptive object detection. In Proc. CVPR, pages 5291-5300, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.605, + 0.472, + 0.66 + ], + "angle": 0, + "content": "[25] Xiaotong Li, Yixiao Ge, Kun Yi, Zixuan Hu, Ying Shan, and Ling-Yu Duan. mc-beit: Multi-choice discretization for image bert pre-training. In Proc. ECCV, pages 231-246. Springer, 2022. 1, 2, 6, 7, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.661, + 0.472, + 0.689 + ], + "angle": 0, + "content": "[26] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. Proc. ICLR, 2019. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.691, + 0.472, + 0.745 + ], + "angle": 0, + "content": "[27] Yang Luo, Zhineng Chen, and Xieping Gao. Self-distillation augmented masked autoencoders for histopathological image classification. arXiv preprint arXiv:2203.16983, 2022. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.748, + 0.472, + 0.815 + ], + "angle": 0, + "content": "[28] Zhenyuan Ning, Denghui Du, Chao Tu, Qianjin Feng, and Yu Zhang. Relation-aware shared representation learning for cancer prognosis analysis with auxiliary clinical variables and incomplete multi-modality data. IEEE TMI, 41(1):186-198, 2021. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.472, + 0.9 + ], + "angle": 0, + "content": "[29] Samiksha Pachade, Prasanna Porwal, Dhanshree Thulkar, Manesh Kokare, Girish Deshmukh, Vivek Sahasrabuddhe, Luca Giancardo, Gwenolé Quellec, and Fabrice Mériaudeau. Retinal fundus multi-disease image dataset (rfmid): A dataset for multi-disease detection research. Data, 6(2):14, 2021. 6" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.472, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.893, + 0.161 + ], + "angle": 0, + "content": "[30] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, Luca Antiga, et al. Pytorch: An imperative style, high-performance deep learning library. In NeurIPS, 2019. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.164, + 0.893, + 0.233 + ], + "angle": 0, + "content": "[31] Ryan Poplin, Avinash V Varadarajan, Katy Blumer, Yun Liu, Michael V McConnell, Greg S Corrado, Lily Peng, and Dale R Webster. Prediction of cardiovascular risk factors from retinal fundus photographs via deep learning. Nat. Biomed. Eng., 2(3):158-164, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.234, + 0.893, + 0.275 + ], + "angle": 0, + "content": "[32] Yu Rong, Wenbing Huang, Tingyang Xu, and Junzhou Huang. Droppedge: Towards deep graph convolutional networks on node classification. In Proc. ICLR, 2020. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.278, + 0.893, + 0.345 + ], + "angle": 0, + "content": "[33] Hannah Spitzer, Kai Kiwitz, Katrin Amunts, Stefan Harmeling, and Timo Dickscheid. Improving cytoarchitectonic segmentation of human brain areas with self-supervised siamese networks. In Proc. MICCAI, pages 663-671. Springer, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.348, + 0.893, + 0.404 + ], + "angle": 0, + "content": "[34] Aiham Taleb, Matthias Kirchler, Remo Monti, and Christoph Lippert. Contig: Self-supervised multimodal contrastive learning for medical imaging with genetics. In Proc. CVPR, pages 20908-20921, 2022. 1, 3, 6, 7, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.406, + 0.893, + 0.46 + ], + "angle": 0, + "content": "[35] Aiham Taleb, Christoph Lippert, Tassilo Klein, and Moin Nabi. Multimodal self-supervised learning for medical image analysis. In Proc. IPMI, pages 661-673. Springer, 2021. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.462, + 0.893, + 0.517 + ], + "angle": 0, + "content": "[36] Aiham Taleb, Winfried Loetzsch, Noel Danz, Julius Severin, Thomas Gaertner, Benjamin Bergner, and Christoph Lippert. 3d self-supervised methods for medical imaging. Proc. NeurIPS, 33:18158-18172, 2020. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.519, + 0.893, + 0.573 + ], + "angle": 0, + "content": "[37] Katarzyna Tomczak, Patrycja Czerwińska, and Maciej Wiznerowicz. Review the cancer genome atlas (tcga): an immeasurable source of knowledge. Contemp. Oncol., 2015(1):68-77, 2015. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.576, + 0.893, + 0.673 + ], + "angle": 0, + "content": "[38] Rami S Vanguri, Jia Luo, Andrew T Aukerman, Jacklynn V Egger, Christopher J Fong, Nataly Horvat, Andrew Pagano, Jose de Arimateia Batista Araujo-Filho, Luke Geneslaw, Hira Rizvi, et al. Multimodal integration of radiology, pathology and genomics for prediction of response to pd-(l) 1 blockade in patients with non-small cell lung cancer. Nature cancer, 3(10):1151-1164, 2022. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.675, + 0.893, + 0.729 + ], + "angle": 0, + "content": "[39] Wenguan Wang, Tianfei Zhou, Fisher Yu, Jifeng Dai, Ender Konukoglu, and Luc Van Gool. Exploring cross-image pixel contrast for semantic segmentation. In Proc. ICCV, pages 7303-7313, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.732, + 0.893, + 0.787 + ], + "angle": 0, + "content": "[40] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In Proc. CVPR, pages 14668-14678, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.789, + 0.893, + 0.844 + ], + "angle": 0, + "content": "[41] LI Wuyang, YANG Chen, LIU Jie, LIU Xinyu, GUO Xiaqing, and YUAN Yixuan. Joint polyp detection and segmentation with heterogeneous endoscopic data. In Proc. ISBI Workshop, pages 69-79. CEUR-WS Team, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.846, + 0.893, + 0.9 + ], + "angle": 0, + "content": "[42] Junfei Xiao, Yutong Bai, Alan Yuille, and Zongwei Zhou. Delving into masked autoencoders for multi-label thorax disease classification. In Proc. WACV, pages 3588-3600, 2023. 1, 3" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.893, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.946, + 0.518, + 0.957 + ], + "angle": 0, + "content": "21461" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[43] Zhenda Xie, Zheng Zhang, Yue Cao, Yutong Lin, Jianmin Bao, Zhuliang Yao, Qi Dai, and Han Hu. Simmim: A simple framework for masked image modeling. In Proc. CVPR, pages 9653-9663, 2022. 1, 2, 3, 6, 7, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.149, + 0.47, + 0.217 + ], + "angle": 0, + "content": "[44] Xiaohan Xing, Zhen Chen, Meilu Zhu, Yuenan Hou, Zhifan Gao, and Yixuan Yuan. Discrepancy and gradient-guided multi-modal knowledge distillation for pathological glioma grading. In Proc. MICCAI, pages 636-646. Springer, 2022. 1, 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.22, + 0.47, + 0.274 + ], + "angle": 0, + "content": "[45] Qiushi Yang, Xiaqing Guo, Zhen Chen, Peter YM Woo, and Yixuan Yuan. D2-net: Dual disentanglement network for brain tumor segmentation with missing modalities. IEEE TMI, 41(10):2953-2964, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.277, + 0.47, + 0.33 + ], + "angle": 0, + "content": "[46] Qiushi Yang and Yixuan Yuan. Learning dynamic convolutions for multi-modal 3d mri brain tumor segmentation. In Brainlesion: MICCAI Workshop, pages 441-451. Springer, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.333, + 0.469, + 0.387 + ], + "angle": 0, + "content": "[47] Zhuoning Yuan, Yan Yan, Milan Sonka, and Tianbao Yang. Large-scale robust deep auc maximization: A new surrogate loss and empirical studies on medical image classification. In Proc. ICCV, pages 3040-3049, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.39, + 0.469, + 0.431 + ], + "angle": 0, + "content": "[48] Jinghao Zhou, Chen Wei, Huiyu Wang, Wei Shen, Cihang Xie, Alan Yuille, and Tao Kong. Image bert pre-training with online tokenizer. In Proc. ICLR, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.433, + 0.469, + 0.487 + ], + "angle": 0, + "content": "[49] Lei Zhou, Huidong Liu, Joseph Bae, Junjun He, Dimitris Samaras, and Prateek Prasanna. Self pre-training with masked autoencoders for medical image analysis. arXiv preprint arXiv:2203.05573, 2022. 1, 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.487 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.946, + 0.519, + 0.956 + ], + "angle": 0, + "content": "21462" + } + ] +] \ No newline at end of file diff --git a/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/3ca9548a-636d-4952-80cd-106e032bd384_origin.pdf b/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/3ca9548a-636d-4952-80cd-106e032bd384_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..e469ff84292761bb1c285714a3f5b07598540fd1 --- /dev/null +++ b/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/3ca9548a-636d-4952-80cd-106e032bd384_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:54f605f31e35d26a933dde8117f2bc030ea5a072e80397c9b7b3d7a8768b9856 +size 2190544 diff --git a/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/full.md b/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/full.md new file mode 100644 index 0000000000000000000000000000000000000000..a545d096c6cb28f12c0c3d3e46680bddc7c157dc --- /dev/null +++ b/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/full.md @@ -0,0 +1,369 @@ +# MRM: Masked Relation Modeling for Medical Image Pre-Training with Genetics + +Qiushi Yang + +Wuyang Li + +Baopu Li3 + +Yixuan Yuan $^{1,2*}$ + +$^{1}$ City University of Hong Kong $^{2}$ The Chinese University of Hong Kong $^{3}$ Independent Researcher + +{qsyang2-c, wuyangli2-c}@my.cityu.edu.hk. + +bpliu.cuhk@gmail.com + +yxyuan@ee.cuhk.edu.hk + +# Abstract + +Modern deep learning techniques on automatic multimodal medical diagnosis rely on massive expert annotations, which is time-consuming and prohibitive. Recent masked image modeling (MIM)-based pre-training methods have witnessed impressive advances for learning meaningful representations from unlabeled data and transferring to downstream tasks. However, these methods focus on natural images and ignore the specific properties of medical data, yielding unsatisfying generalization performance on downstream medical diagnosis. In this paper, we aim to leverage genetics to boost image pre-training and present a masked relation modeling (MRM) framework. Instead of explicitly masking input data in previous MIM methods leading to loss of disease-related semantics, we design relation masking to mask out token-wise feature relation in both self- and cross-modality levels, which preserves intact semantics within the input and allows the model to learn rich disease-related information. Moreover, to enhance semantic relation modeling, we propose relation matching to align the sample-wise relation between the intact and masked features. The relation matching exploits inter-sample relation by encouraging global constraints in the feature space to render sufficient semantic relation for feature representation. Extensive experiments demonstrate that the proposed framework is simple yet powerful, achieving state-of-the-art transfer performance on various downstream diagnosis tasks. Codes are available at https://github.com/CityU-AIM-Group/MRM. + +# 1. Introduction + +In the medical diagnosis [44, 34, 38, 28, 6, 5], the largescale multimodal biobank data, e.g., images and genetics, is necessary for a reliable diagnosis, overcoming the limited scale and disease information of a single-modality + +![](images/6b0ce549fceda1ce6a9605b5b97bcd214d2b76ee6e91b598128d86a8e9eacd0a.jpg) + +![](images/f18ab18d9d702730946f58a822f9406fb304a8098ba1f0589b24879b8a0ce28a.jpg) + +![](images/3f1dd1d615c93a1dbd8d2feea6c1614cf1c70b5e9e079b9198c166c2c3756294.jpg) +Figure 1. Comparison of different masking strategies on natural and medical data. (a): Existing MIM methods mask out input natural images and infer the missing content to learn semantic representations via reconstruction task. (b): Recent pre-training approaches for disease diagnosis explicitly employ MIM on input medical data (e.g., medical images and genome), whilst they are prone to lose tiny disease regions and cause non-tractable reconstruction. (c): Our method masks token-wise feature relation across multimodal data and matches sample-wise relation between the intact and masked features, preserving intact semantic regions and enriching relation information. + +![](images/85c3242344fc994459dc4baa0aa4f84e019cb7b0548b4c6e11a08ea5b156c504.jpg) + +dataset. However, the prohibitive expert annotations of large-scale datasets make it difficult to train a conventional deep model [44, 45, 41, 46, 47]. Particularly, in this multimodal scenario, the requirements of the experts in various medical fields prevent enough annotation access, severely limiting the grounding of the automatic diagnosis system. + +To address this, the most prospering trend [16, 43, 4, 34, 13, 35, 36, 12, 27] is self-supervised pre-training, e.g., masked image modeling (MIM) [16, 43, 13, 42], aiming to train a label-free model with adequate generalization capacity. Existing MIM methods [16, 43, 4, 25, 13, 42, 49] mask out a high portion of patches within input images and infer the missing content, as suggested in Figure 1 (a). They make use of contextual information to glance the semantics and reconstruct the entire images, which performs a mask-and-reconstruct task to pre-train the model without annotation and transfer meaningful representations to various + +downstream tasks for improving label-efficient fine-tuning. + +Though achieving great success, most works [16, 43, 4, 40, 10, 25, 19] are designed for natural images, ignoring the essential differences between medical data and natural images. Therefore, we empirically find that existing MIM CANNOT works well in medical data (see Table 1), and even totally fails to reconstruct diseases (see Figure 3). The reasons derive from a critical observation regarding the significant data differences, which can be summarized into two challenges. Firstly, compared with natural images, there are limited semantic regions in medical data. As shown in Figure 1 (a), the semantic-rich foreground is always the main body of the natural image, while the rest non-informative background region only represents a minority part. Differently, in the medical image (Figure 1 (b)), the majority of regions are backgrounds, and the informative disease regions are usually on a tiny scale. Under the strategy of masking entire tokens in existing MIM methods [16, 43, 4, 40, 10, 25, 19], if the disease tokens are masked out, the disease-related semantic is totally missing with a catastrophic information loss, leading to a nontractable reconstruction. This issue also exists between genomics and natural images. The semantic regions in genomics, i.e., the disease-related patterns, mainly lie in a minority of genome segments [28, 5, 7]. Hence, instead of masking the whole input token, these observations motivate us to delve into the masking of token-level relation, which preserves abundant semantic discriminability and adequate self-supervision, as illustrated in Figure 1 (c) Left. + +The second challenge is the limited semantic relation. In a natural image, the background and foreground relationship, e.g., the bird in the sky and the person in a room, tends to be prosperous and abundant, serving a critical role in semantic-level learning [39, 24]. In contrast, in each medical data sample, the disease-aware relation is limited and insufficient to provide enough discriminative evidence. The reason lies in that the medical datasets are usually collected from the same human organ, e.g., the fundus, containing redundant and similar anatomical patterns, e.g., the capillary, which severely prevent the relation modeling between the disease and the complex medical scene. This challenge hampers reliable relation learning in existing MIM methods, and may incur an inevitable overfitting to noninformative relation within the background [40, 25, 23, 3]. Hence, considering the limited semantic relation in each data sample, we are committed to going beyond the self-supervised learning for an independent and individual data sample, and propose to encourage global constraints for exploiting inter-sample relation (see Figure 1 (c) Right). + +To combat above challenges, as shown in Figure 1 (c), we present MRM, a masked relation modeling from a unified view of relation, containing relation masking and relation matching, to rationally pre-train multimodal medical + +images with genetics. To preserve intact semantic information within raw input, we devise relation masking strategy to allow the model to learn disease-related semantics. Instead of masking out input data, the relation masking investigates token-wise relation within feature representations in both self- and cross-modality levels and masks out the relation among all multimodal tokens. The relation masking endows the model to explicitly learn global dependency from raw data without missing disease-related semantic information. Furthermore, to improve the semantic relation modeling, the relation matching is designed to provide global constraint by aligning the feature relation across multiple samples. Specifically, relation matching exploits sample-wise relation in both self- and cross-modality levels to encourage the relation consistency between the intact and masked features. This enjoys the complementary advantages of persample pixel-wise reconstruction loss and boosts the transfer ability of the model. With the pre-trained model, we can obtain the feature representation that can be transferred to supervised downstream diagnosis tasks for boosting label-efficient fine-tuning, alleviating the severe demand for specialized annotations. + +In summary, our contributions fall into four parts: + +- We identify the challenges of current MIM methods on medical data, and present MRM, a masked relation modeling using multimodal medical data to facilitate image representation learning. +- Towards the issue of limited semantic regions in medical data, we design relation masking to mask tokenwise feature relation across self- and cross-modality. Different from MIM explicitly masking inputs, relation masking preserves disease semantics within inputs, endowing a powerful mask-and-construct task. +- Moreover, to enrich the semantic relation among diseases, the relation matching is proposed to capture abundant disease-related relation by aligning sample-wise feature relation between intact and masked features in both self- and cross-modality levels. +- Extensive transfer evaluation on various downstream tasks using two public medical pre-training datasets demonstrate that our framework performs superior transfer ability over state-of-the-art methods. + +# 2. Related Work + +# 2.1. Visual Pre-training + +In recent years, self-supervised visual pre-training [8, 9, 15, 17, 11, 16, 43, 48, 4] has achieved exceptional transfer performance in various downstream visual tasks, which + +![](images/3b4916f3987b8ea0e696a6ff15de0887dc8eb89915e6fe6b20443e8b644423d6.jpg) +Figure 2. Overview of masked relation modeling (MRM). MRM contains relation masking to mask out token-wise feature relation with preserving disease-related semantics, and the relation matching to enforce sample-wise relation consistency for global semantic modeling. + +can be divided into two categories. The first is contrastive-based methods [8, 15, 17, 35, 35] that aim to project similar samples nearby while pull dissimilar ones far away in the feature space. For instance, SimCLR [8] imposes two embeddings from a sample under different views consistency via InfoNCE loss, and BYOL [15] merely pushes the positive pairs together with a momentum encoder for boosting transfer performance. Moreover, inspired by the progress of masked language modeling on natural language processing [20], masked image modeling (MIM)-based approaches [16, 48, 43, 4, 3, 10, 3] are proposed to pre-train visual models and exhibit remarkable transfer performance. MAE [16] formulates a pixel-wise reconstruction task to mask out a high portion of input patches and infer the masked ones with visible tokens via an autoencoder. Afterwards, many followups [43, 3, 19, 10] devise MIM models to improve the representation learning. However, they mainly focus on natural images and ignore the essential differences between the medical data and natural images, thereby delivering unsatisfying transfer results [27, 49]. + +# 2.2. Medical Self-supervised Learning + +Most works [35, 36, 2, 34] on medical self-supervised learning extend the ideas of contrastive learning and develop customized strategies to pre-train models. 3DSSL [36] adopt a series of proxy tasks to present a 3D versions self-supervised model and achieves compelling transfer results. ContIG [34] crafts a multimodal pre-training framework using image and genome data via contrastive learning and delivers competitive transfer ability. Although efficiency, these contrastive-based approaches strongly rely on well-defined data augmentations to construct positive + +pairs, which are difficult for medical data, especially for structured data, e.g., genetics. Most recently, some studies [13, 42, 27, 49] adopt MIM to self-supervised pre-train medical models. MedicalMAE [49] introduces a self pretraining paradigm by employing MAE [16] to pre-train the model and achieve superior performance. To perform multimodal pre-training, $\mathrm{M}^{3}\mathrm{3AE}$ [13] randomly masks out the tokens of image and language inputs and aims to infer the whole data using visible tokens. All of them still adopt input masking strategy, which may incur tiny disease-related region missing and non-tractable reconstruction. Differently, we design a novel relation masking strategy in the feature space and retain intact disease-related information. + +# 2.3. Learning from Images and Genetics + +Genetics can provide comprehensive information for many disease diagnosis and treatment planning [38, 28, 6, 5, 7], which attract much attention from researchers. Many works [44, 34, 38] formulate a multimodal learning task by jointly leveraging genetics and medical images to exploit complementary knowledge. Considering that the genetics may be difficult to acquire in many clinical applications, recent studies [34, 7] aim to design pre-training models using images and genetics for improving practical image-based diagnosis. However, they merely use contrastive constraint to perform self-supervised learning, while they fail to adopt the efficient mask-and-reconstruct task to pre-train models. In this work, we aim to leverage genetics with images to boost the visual representation learning via semantic relation modeling, which discovers both inner-sample and intersample relation to achieve more effective pre-training. + +# 3. Masked Relation Modeling + +In this section, we start by introducing the preliminaries of vision Transformer and masked image modeling. We then present the masked relation modeling (MRM), containing relation masking and relation matching. The overall pre-training and transfer inference of the framework are described at the end of the section. + +# 3.1. Preliminaries + +Vision Transformer (ViT). Given an image $x \in \mathbb{R}^{c \times h \times w}$ , ViT first splits it into $n = hw / p^2$ non-overlapping patches $x_P = \{x_1; x_2; \ldots; x_n\}$ , $x_i \in \mathbb{R}^{c \times p \times p}$ , where $p \times p$ denotes the size of each patch. Afterwards, the patches $x_P$ are tokenized as a sequence of token embeddings $e = \{e_1; e_2; \ldots; e_n\}$ , $e_i \in \mathbb{R}^{1 \times d}$ , where $d$ is the dimension of each token, via a linear projection with positional embeddings. The embeddings $e$ are then processed by a cascade of multi-head self-attention layers to capture global information, where the self-attention is described as follow: + +$$ +\operatorname {A t t e n t i o n} (e) = \operatorname {S o f t m a x} \left(\frac {1}{\sqrt {d}} Q K ^ {T}\right) V, \tag {1} +$$ + +where $K = eW^{K}$ , $Q = eW^{Q}$ , $V = eW^{V}$ , $K, Q, V \in \mathbb{R}^{1 \times d}$ is the key, query and value obtained by the linear projection via $W^{K}, W^{Q}, W^{V}$ , respectively. Each layer of the ViT encoder contains a multi-head self-attention block, and the feature representation is produced by multiple layers within the encoder. + +Masked Image Modeling (MIM). The input patches $x_{p}$ are randomly masked out with a high ratio, denoted as masked patches $x_{M}$ . The remaining visible patches $x_{V}$ are fed into ViT encoder $f(\cdot)$ to capture features $z = f(x_{V})$ , which are then sent to a lightweight decoder $h(\cdot)$ to recover the missing patches $\hat{x} = h(z)$ of the input data. The overall framework is optimized by mean-squared error (MSE) reconstruction loss function $\mathcal{L}_{\mathrm{MIM}}$ between the recovered patches $\hat{x}$ and masked patches $x_{M}$ as: + +$$ +\mathcal {L} _ {\mathrm {M I M}} = \mathbb {E} | | x _ {M} - h (f (x _ {V})) | | _ {2} ^ {2}. \tag {2} +$$ + +Overview of Masked Relation Modeling (MRM). As illustrated in Figure 2, the proposed MRM consists of the relation masking strategy to mask out feature relation and preserve intact disease-related semantics, and the relation matching to offer global constraints for relation modeling. With the input image $x_{I}$ and genome $x_{G}$ , the ViT encoder $f_{I}$ and self-normalizing network (SNN) [22] $f_{G}$ produces masked feature representations $z_{I,M},z_{G,M}$ for image and genome via relation masking. Parallely, the intact representations $z_{I},z_{G}$ are obtained by two encoders without relation masking. Afterwards, the masked features $z_{I,M},z_{G,M}$ are aggregated with the intact features $z_{G},z_{I}$ from the other modality to yield the fused features $z_{I}^{F},z_{G}^{F}$ , respectively. + +These fused feature are then put into the image decoder $h_I$ and the genome decoder $h_G$ to reconstruct original data $\hat{x}_I$ and $\hat{x}_G$ . The relation matching is employed on intact and masked feature representations with the data reconstruction loss to jointly optimize the overall framework. + +# 3.2. Relation Masking + +Due to the medical data usually appearing tiny disease patterns, current input-level masking strategies may discard disease-related semantics and hardly learn informative feature representation. To address this problem, the relation masking is proposed to mask token-wise feature relation from self- and cross-modality perspectives in a cascading manner, which can maintain intact input disease-related information during pre-training. The operations of relation masking for image and genome are parallel, for brevity, we adopt the image branch to introduce. + +Self-modality relation masking. In the $i$ -th relation masking block, given $z_{I}^{0}$ as the input image token, we first calculate $K_{I}^{S}, Q_{I}^{S}, V_{I}^{S}$ as its key, query and value, respectively. Then, the normalized feature dependency in tokens is obtained by computing the relation between the key $K_{I}^{S}$ and query $Q_{I}^{S}$ of the image feature as follows: + +$$ +R _ {\text {s e l f}} = \operatorname {S o f t m a x} \left(\frac {1}{\sqrt {d}} Q _ {I} ^ {S} \cdot \left(K _ {I} ^ {S}\right) ^ {T}\right). \tag {3} +$$ + +This self-modality relation $R_{\mathrm{self}}$ reflects the token-wise semantic correspondence within the image feature. The tokens with stronger relation contain more interactive and informative semantics. To enable the model to capture intramodality feature representation via the reconstruction task, on the top of self-modality relation, we aim to break the strong dependency across informative regions by relation masking. Specifically, we mask out high-intensity elements with a ratio $\tau_I$ in self-modality relation: + +$$ +R _ {\text {s e l f}} ^ {M} [ p, q ] = \left\{ \begin{array}{c c} R _ {\text {s e l f}} [ p, q ] & \text {i f} R _ {\text {s e l f}} [ p, q ] < r _ {\text {s e l f}} ^ {p} \\ 0 & \text {e l s e ,} \end{array} \right. \tag {4} +$$ + +where $r_{\mathrm{self}}^p$ refers to the intensity of the top- $\tau_I$ element among the $p$ -th row of the self-modality relation $R_{\mathrm{self}}$ matrix. Note that the masked elements are selected in each row of the self-modality relation matrix to remove the semantic correspondence for all tokens with the same intensity. Afterwards, the masked relation matrix $R_{\mathrm{self}}^M$ is forwarded to produce the token $z_I^S = R_{\mathrm{self}}^M V_I^S$ for subsequent data flow. With the self-modality relation masking, the relative important dependency within the modality is discarded and we enforce the model to reconstruct the original image with the remaining weak feature relation. Thus, the model can capture disease-related feature representation of images. + +Cross-modality relation masking. In an attempt to incorporate multimodal knowledge, after the self-modality self-attention layer, we perform cross-modality attention between the image and genome features. Precisely, obtained + +the image and genome tokens $z_{I}^{S},z_{G}^{S}$ masked via selfmodality relation masking, we compute token-wise crossmodality relation to capture semantic correspondence between image and genome features: + +$$ +R _ {\text {c r o s s}} = \operatorname {S o f t m a x} \left(\frac {1}{\sqrt {d}} Q _ {I} ^ {C} \cdot \left(K _ {G} ^ {C}\right) ^ {T}\right), \tag {5} +$$ + +where $K_{G}^{C}$ means the key of genome feature $z_{G}^{S}$ , and $Q_{I}^{C}$ represents the query of image feature $z_{I}^{S}$ in the cross-attention layer. This cross-modality attention can amalgamate two modality knowledge and improve the feature representation towards disease-related information. Then, to allow the model to learn complementary multimodal knowledge and the relation between two modalities, we perform cross-modality relation masking by removing strong semantic correspondence between image and genome features: + +$$ +R _ {\text {c r o s s}} ^ {M} [ p, q ] = \left\{ \begin{array}{c l} R _ {\text {c r o s s}} [ p, q ] & \text {i f} R _ {\text {c r o s s}} [ p, q ] < r _ {\text {c r o s s}} ^ {p} \\ 0 & \text {e l s e ,} \end{array} \right. \tag {6} +$$ + +where $r_{\mathrm{cross}}^p$ denotes the intensity of the top- $\tau_I$ element among the $p$ -th row of the cross-modality relation matrix $R_{\mathrm{cross}}$ . With the masked relation $R_{\mathrm{cross}}^M$ , we can obtain the fused image token $z_I^C = R_{\mathrm{cross}}^M V_G^C$ , where $V_G^C$ means the value of the genome feature. + +Reconstruction with relation masking. We feed the input data into two networks shared parameters, where the first network consists of a ViT encoder to yield intact image feature $z_{I}$ and a SNN encoder with self-attention blocks to produce genome feature $z_{G}$ . Parallely, the second network employs the proposed self- and cross-modality relation masking in first two attention blocks to generate masked features $z_{I,M}, z_{G,M}$ for image and genome, respectively. Afterwards, the masked features are incorporated with the intact feature from the other modality and produce amalgamated features $z_{I}^{F} = \text{concat}[z_{I,M}; z_{G}]$ , $z_{G}^{F} = \text{concat}[z_{G,M}; z_{I}]$ for images and genome. The fused features are then put into the decoders $h_{I}(\cdot), h_{G}(\cdot)$ to reconstruct image and genome $\hat{x}_{I} = h_{I}(z_{I}^{F}), \hat{x}_{G} = h_{G}(z_{G}^{F})$ . The overall loss function for the reconstruction of image and genome is: + +$$ +\mathcal {L} _ {\text {r e c o n}} = \left\| h _ {I} \left(z _ {I} ^ {F}\right) - x _ {I} \right\| _ {2} ^ {2} + \left\| h _ {G} \left(z _ {G} ^ {F}\right) - x _ {G} \right\| _ {2} ^ {2}. \tag {7} +$$ + +The relation masking strategy exploits the token-wise feature relation for mask-and-reconstruct task. It is worth noting that although the strong relation is removed, the intrinsic information within the data is retained [32]. Therefore, with the original complete image and genome as inputs, our relation masking can preserve the intact disease-related semantics. With the relation masking-based reconstruction task, the self-modality relation is encouraged to be recovered by the model to capture disease-related information + +within each modality, and the cross-modality relation is enforced to reconstruct to learn abundant multimodal knowledge to improve the disease-related representation for effective downstream diagnosis tasks transfer. + +# 3.3. Relation Matching + +Considering that the disease-aware relation among diseases is limited in medical data, to provide sufficient semantic relation, we propose relation matching, a global constraint to align the sample-wise relation across self- and cross-modality samples to perform global constraints in the feature space. + +Self-modality matching. Assume one minibatch contains $B$ multimodal pairs $\{x_I^i,x_G^i\}_{i = 1}^B$ , we can obtain the intact feature representations $\{z_I^i,z_G^i\}_{i = 1}^B$ and masked ones $\{z_{I,M}^{i},z_{G,M}^{i}\}_{i = 1}^{B}$ via the proposed relation masking strategy. Firstly, we compute the sample-wise relation $\{R_{\mathrm{II}}^{i,j}\}_{i,j = 1}^{B},\{R_{\mathrm{GG}}^{i,j}\}_{i,j = 1}^{B}$ across all intact features of image and genome, respectively: + +$$ +R _ {\mathrm {I I}} ^ {i, j} = \operatorname {s i m} \left(z _ {I} ^ {i}; z _ {I} ^ {j}\right) \tag {8} +$$ + +$$ +R _ {\mathrm {G G}} ^ {i, j} = \operatorname {s i m} \left(z _ {G} ^ {i}; z _ {G} ^ {j}\right), +$$ + +where $\mathrm{sim}(\cdot ;\cdot)$ denotes the similarity between two features, here we adopt the cosine similarity. Similarly, we acquire the sample relation among masked features: + +$$ +R _ {\mathrm {I I}, \mathrm {M}} ^ {i, j} = \operatorname {s i m} \left(z _ {I, M} ^ {i}; z _ {I, M} ^ {j}\right), \tag {9} +$$ + +$$ +R _ {\mathrm {G G}, \mathrm {M}} ^ {i, j} = \operatorname {s i m} (z _ {G, M} ^ {i}; z _ {G, M} ^ {j}). +$$ + +We aim to ensure the relation consistency between intact and masked features. The matching objective for self-modality feature relation can be formulated as: + +$$ +\mathcal {L} _ {\text {s e l f}} = \frac {1}{2 B ^ {2}} \sum_ {i = 1} ^ {B} \sum_ {j = 1} ^ {B} \left| \left| R _ {\mathrm {I I}} ^ {i, j} - R _ {\mathrm {I I}, \mathrm {M}} ^ {i, j} \right| \right| _ {2} ^ {2} + \left| \left| R _ {\mathrm {G G}} ^ {i, j} - R _ {\mathrm {G G}, \mathrm {M}} ^ {i, j} \right| \right| _ {2} ^ {2}. \tag {10} +$$ + +Cross-modality matching. Furthermore, to incorporate multimodal information and bridge the gap of different modalities, we compute the cross-modality relation: + +$$ +R _ {\mathrm {I G}} ^ {i, j} = \operatorname {s i m} \left(z _ {I} ^ {i}; z _ {G} ^ {j}\right), \tag {11} +$$ + +$$ +R _ {\mathrm {I G , M}} ^ {i, j} = \mathrm {s i m} (z _ {I, M} ^ {i}; z _ {G, M} ^ {j}), +$$ + +where $\{R_{\mathrm{IG}}^{i,j}\}_{i,j = 1}^{B}$ represents the cross-modality relation across intact multimodal features, and $\{R_{\mathrm{IG,M}}^{i,j}\}_{i,j = 1}^{B}$ means the relation across masked ones. We intend to ensure the cross-modality relation to be invariant between masked and intact features. The cross-modality feature relation can be calculated as: + +$$ +\mathcal {L} _ {\text {c r o s s}} = \frac {1}{B ^ {2}} \sum_ {i = 1} ^ {B} \sum_ {j = 1} ^ {B} \left| \left| R _ {\mathrm {I G}} ^ {i, j} - R _ {\mathrm {I G}, \mathrm {M}} ^ {i, j} \right| \right| _ {2} ^ {2}. \tag {12} +$$ + +Table 1. Comparison with state-of-the-art pre-training algorithms via fine-tuning evaluation on four downstream retinal image-based tasks. + +
MethodMasking LevelAPTOSRFMiDPALMCRP
InputRelationQwKappa ↑ROC-AUC ↑Dice-Score ↑MSE ↓ROC-AUC ↑
Training from scratch (baseline)--83.2592.9179.443.40558.05
Contrastive-based Pre-training Methods
SimCLR [8]--84.5093.7573.183.42663.92
MoCo v3 [17]--85.0394.0275.733.42165.33
ContIG [34]--86.2794.5980.253.18473.57
MIM-based Pre-Training Methods
MAE [16]✓✗84.0692.7174.283.48864.29
SimMIM [43]✓✗84.6793.8072.733.45066.08
MultiMAE [3]✓✗85.5994.2675.923.41167.51
M3AE [13]✓✗86.8594.7277.353.39468.39
mc-BEiT [25]✓✗87.1594.3777.403.37266.38
AttMask [19]✓✗87.7394.9178.593.26269.40
MRM✗✓89.8396.3181.453.10775.90
+ +With the self- and cross-modality feature relation, we can formulate the overall relation matching objective as: + +$$ +\mathcal {L} _ {\text {m a t c h}} = \mathcal {L} _ {\text {s e l f}} + \mathcal {L} _ {\text {c r o s s}}. \tag {13} +$$ + +The relation matching encourages global constraints in the feature space to provide sufficient semantic relation, which enjoys the complementary advantages of pixel-wise data reconstruction loss in Eq. (7). + +# 3.4. Pre-training and Transfer Inference + +In the pre-training phase, the image and genome as multimodal inputs are fed into the model. We adopt the proposed relation masking to generate masked features, and employ the relation matching as the global constraint with the data reconstruction loss to jointly optimize the overall framework: + +$$ +\mathcal {L} _ {\text {o v e r a l l}} = \mathcal {L} _ {\text {r e c o n}} + \lambda \mathcal {L} _ {\text {m a t c h}}, \tag {14} +$$ + +where $\lambda$ denotes the balanced coefficient to control contributions of the reconstruction task and the relation matching. During the phase of downstream image-based fine-tuning, we discard the genome branch and utilize the image encoder to extract the feature representation without relation masking. The pre-trained encoder following a randomly initial task-relevant head is fine-tuned on downstream tasks for evaluation. + +# 4. Experiments + +We pre-train MRM on two multimodal datasets involving retinal images with genetics, and pathology images with genetics, respectively. To evaluate the quality of the representations learned on retinal images, we transfer the pre-trained model to four downstream retinal image-based tasks. As for the model pre-trained on pathology images, we assess it on a downstream pathology image-based task. The gene-image association analysis is performed to study the relation between images and genetics towards disease diagnosis. Finally, we extend our method to image pre-training to verify the effectiveness on single modality. + +# 4.1. Experimental Setup + +# 4.1.1 Retinal Images with Genetics + +Pre-training. We use UKB [33] to conduct the self-supervised pre-training, which is one of the largest multimodal images and genetics datasets. Following the previous work ContIG [34], we leverage the retinal fundus dataset as the pre-training set, which contains 155,238 images, and the genetics including 155,238 Raw-SNP samples, 145,206 PGS samples and 93,216 burden scores. + +Downstream Transfer. We introduce four tasks to evaluate and compare the effectiveness of the model pre-training. + +1) Diabetic Retinopathy Detection (APTOS). The APTOS [1] is a fundus disease dataset including 35,126 2D images across five categories. All images are resized as $224 \times 224$ for efficient fine-tuning. We split $80\%$ as the training set to fine-tune the pre-trained MRM model, and the remaining $20\%$ as the test set is used to evaluate the performance. The Quadratic Weighted Kappa (QwKappa) [14] is adopted as the metric to measure the agreement between the prediction and ground truth. +2) Retinal Fundus Disease Classification (RFMiD). The Retinal Fundus Multi-disease Image Dataset (RFMiD) [29] consists of 3200 annotated retinal fundus images of 46 eye diseases. RFMiD formulates a multi-label classification task since the images may contain multiple conditions. We split $80\%$ as the training set and $20\%$ as the test set. The area under the ROC curve (ROC-AUC) is used as the metric to evaluate the classification results. +3) Pathological Myopia Segmentation (PALM). The PALM dataset [18] contains 1200 images with disc and atrophy segmentation annotations. We use 800 images as the training split and 400 images as test split. The dice score is adopted as the segmentation evaluation metric. +4) Cardiovascular Risk Prediction (CRP). The retinal fundus images of UKB dataset can also be utilized to CRP including age, sex, smoking status, systolic and diastolic blood pressure (SBP, DBP), and body mass index (BMI) [31], formulating a regression with classification + +Table 2. Transfer results on downstream pathological image task. + +
MethodGG
Acc ↑ROC-AUC ↑
Training from scratch (baseline)73.8390.16
Contrastive-based Pre-training
SimCLR [9]74.2490.62
MoCo v3 [11]74.7890.90
ContIG [34]75.1491.25
MIM-based Pre-Training
MAE [16]73.7590.44
SimMIM [43]73.9690.80
MultiMAE [3]74.4591.03
mc-BEI T [25]74.8291.35
AttMask [19]75.3691.75
MRM76.1792.07
+ +task. We use mean squared error (MSE) as the metric for numerical factors, i.e., age, BMI, SBP, DBP, and the ROC-AUC for the categorical factors, i.e., sex and smoking status. + +# 4.1.2 Pathology Images with Genetics + +Pre-training. We use TCGA-GBM with TCGA-LGG dataset [37] to conduct the pre-training, which consists of 736 paired samples of pathology slides and genetic profiles. We resize the curated pathology slides with the shape of $224 \times 224$ as inputs. Considering each patient has multiple curated slides, we select one of them associated with one genetic profile as an input pair. + +Downstream Transfer. We leverage glioma grading (GG) to evaluate performance. The GG can improve the treatment planning for accurate determination. The TCGA dataset contains WHO grading labels including grade II, III and IV. We fine-tune the pre-trained model on training set with $80\%$ data split and evaluate the performance on $20\%$ data split. The accuracy and ROC-AUC are employed as the metrics to measure the classification results. + +# 4.2. Implementation Details + +Following prior works [16, 44], we adopt ViT-base as the image encoder and SNN network as the genome encoder to learn representations. The ViT and SNN models are trained via AdamW [26] and Adam [21], respectively, both with an initial learning rate of $1 \times 10^{-3}$ . We use PyTorch [30] to implement our models, and train all models for 50 epochs with the batch size of 256 for UKB and 8 for TCGA. In relation matching, for efficiency, we randomly select 8 pair of multimodal features to perform matching constraint for two datasets. All comparisons [8, 11, 34, 16, 43, 3, 13, 25, 19] share the same settings to achieve a fair comparison. The balanced coefficient $\lambda$ in Eq. (14) is set as 1.0, and the masking ratios $\tau_{I}, \tau_{G}$ for images and genetics are equal to $75\%$ and $50\%$ , respectively. + +# 4.3. Comparison with State-of-the-arts + +In this section, to assess the quality of feature representations to various downstream tasks, we fine-tune the encoder + +Table 3. Ablation study of each proposed component in relation masking and relation matching on retinal image-based tasks. + +
MaskingMatchingAPTOSRFMiDPALMCRP
RM selfRM crossL selfL crossQwKappaROC-AUC↑ Dice-Score↑ MSE↓ ROC-AUC ↑
83.6590.4972.513.49661.57
✓86.3793.4875.293.35267.21
✓85.1092.7174.203.41864.82
✓✓87.5094.2877.233.28370.52
✓✓✓88.2794.9478.493.21673.73
✓✓✓88.6595.5179.773.16274.27
✓✓✓✓89.8396.3181.453.10775.90
+ +with an initial task-relevant head together on the training set, and evaluate the downstream tasks on the test set. + +Retinal Images with Genetics. We compare MRM pretrained on UKB with state-of-the-art methods [8, 11, 34, 16, 43, 3, 13, 25, 19] on four downstream retinal image-based tasks in Table 1. MRM achieves $89.83\%$ , $96.31\%$ , $81.45\%$ , $3.107$ and $75.90\%$ scores on APTOS, RFMiD, PALM and CRP tasks, respectively, outperforming other comparisons by a clear margin in all tasks including disease classification, segmentation and regression. Particularly, compared with MIM-based pre-training methods, MRM is superior over the second best one AttMask [19] with $2.10\%$ , $1.40\%$ , $2.86\%$ , $0.155$ and $6.50\%$ scores on four tasks. These results reflect that masking out relation and retaining intact information within the input can obtain better feature representation than MIM-based input masking and per-sample reconstruction strategies for medical data. + +Pathology Images with Genetics. To verify the versatility of the proposed framework, we pre-train MRM on pathology image-genome dataset TCGA and fine-tune the model on downstream grade grading task to evaluate the transfer results. From Table 2, compared with other pretraining methods, MRM yields state-of-the-art performance with $76.17\%$ accuracy and $92.07\%$ ROC-AUC scores, indicating its effectiveness and flexibility on various types of medical images. Hence, the proposed MRM is able to achieve significantly better self-supervised leaning. + +# 4.4. Ablation Study + +We ablate the effectiveness of each component in MRM on retinal image dataset. + +Effectiveness of relation masking. We study the effectiveness of the proposed self- and cross-modality relation masking. We start from a baseline that trains the autoencoder to construct the multimodal data, we first mask out a portion of self-modality relation in both image and genome branches. From Table 3, the self-modality relation masking brings performance gains by $2.72\%$ , $2.99\%$ , $2.78\%$ , 0.144 and $5.64\%$ scores on APTOS, RFMiD, PALM and CRP tasks, respectively. Then, we further mask out the cross-modality relation, the results show consistent increases by $1.13\%$ , $0.80\%$ , $1.94\%$ , 0.069 and $3.31\%$ on four tasks. To + +![](images/c2600edaefb30c5cc0d50ca9aa1b2a6a193202d993f1c363225df85f7836040f.jpg) +Figure 3. Comparison of reconstruction results of different methods. From left to right suggests the original input and the reconstructed images by MAE [16], AttMask [19] and our MRM. We can observe that MRM can preserve the disease regions framed in blue while MIM-based methods lose them. + +qualitatively verify the impact of the relation masking, we visualize the reconstruction images of different methods. Figure 3 illustrates that MIM-based approaches [16, 19] lose the tiny disease regions, while MRM can reconstruct almost complete disease regions. These advantages indicate that our relation masking in self- and cross-modality levels can preserve the disease semantics thereby improving the quality of the feature representation. + +Impact of relation matching. To observe the impact of the self- and cross-modality relation matching, on the top of the model with relation masking, we employ the self-modality matching constraint. As implied in Table 3, self-modality matching leads to the transfer result improvements by $0.77\%$ , $0.66\%$ , $1.26\%$ , $0.067$ and $3.21\%$ scores on APTOS, RFMiD, PALM and CRP tasks, respectively. When adding the cross-modality relation matching, the performance continuously grows by $1.56\%$ , $1.37\%$ , $2.96\%$ , $0.109$ and $2.17\%$ scores on four downstream tasks. The results illustrate that both self- and cross-modality relation matching can boost the representation learning, and they can render complementary constraints to achieve sample relation invariant when masking the feature relation. + +Masking ratios. To understand the influence of masking ratios $\tau_{I}$ and $\tau_{G}$ for images and genetics, we fine-tune the pre-trained model on diabetic retinopathy detection task under different masking ratios. Firstly, we mask the self- and cross-modality relation for image features with different ratio $\tau_{I}$ including $10\%$ , $25\%$ , $50\%$ , $75\%$ and $90\%$ . From Figure 4 (a), the best choice for $\tau_{I}$ is $75\%$ , and the performance decreases when diminishing or enlarging the ratio. As the ratio reduces from $75\%$ to $10\%$ , the transfer result drops remarkably by $1.35\%$ . Moreover, we analyze the effect of masking ratio $\tau_{G}$ for genetics and find that $50\%$ is good for + +![](images/74264b881bb2b0105b2c71aacb91d2023bd90bab1df5734caef50fc2a3362c77.jpg) +(a) + +![](images/5ee7566523083381042acc921d1265e0b945a30d9f01a514cd68739cc522d6da.jpg) +(b) +Figure 4. Ablation study. (a) Masking ratios $\tau_{I}$ and $\tau_{G}$ for image and genome. (b) Balanced coefficient $\lambda$ of two loss functions. + +Table 4. Results of gene-image association analysis. + +
MethodFound Regions ↑
Training from scratch4
SimCLR [9]5
MoCo v3 [11]6
ContIG [34]10
MAE [16]8
SimMIM [43]10
MultiMAE [3]13
mc-BEI T [25]14
AttMask [19]16
MRM18
+ +representation learning and transfer results. + +Loss balanced coefficient $\lambda$ . We study the sensitivity of MRM towards the balanced coefficients $\lambda$ for controlling two loss functions $\mathcal{L}_{\mathrm{recon}}$ and $\mathcal{L}_{\mathrm{match}}$ in Eq. (14), as shown in Figure 4 (b). It can be observed that the performance rises with the balanced coefficients $\lambda$ increasing from 0.1 to 1.0, while it plunges when $\lambda$ is larger than 1.0. These suggest that the proposed relation matching leads to beneficial representation learning with the appropriate range of $\lambda$ , either too strong or too weak of the relation matching constraint damage the quality of the feature representation. + +# 4.5. Gene-image Association Analysis + +To obtain an interpretable understanding on how genetics can improve images representation learning, we conduct gene-image association analysis for all models. This association analysis is a statistical tool for finding individual genetic regions correlated with image features according to the disease traits. The better the image representation, the more associated regions are expected to be discovered. Table 4 shows the number of independent regions each model finds, where we observe that MRM finds the most disease-related regions from genetics, explaining why genetics can improve image representation learning in our model. + +# 4.6. Extension to Single Modality Pre-training + +To study the application of the proposed MRM on single modality, we pre-train MRM using merely image modality on retinal dataset from UKB, and evaluate the feature representation on downstream tasks. Specifically, during the pre-training phase, we remove the cross-modality attention layers and adopt self-attention with self-modality relation + +Table 5. Transfer results with single image modality pre-training on retinal image-based tasks. + +
MethodAPTOSRFMiDPALMCRP
QwKappa ↑ROC-AUC ↑Dice-Score ↑MSE ↓ROC-AUC ↑
Training from scratch79.2689.2777.583.44653.56
SimCLR [8]81.4390.5172.523.45359.25
MoCo v3 [17]82.2091.8273.973.43761.73
ContIG [34]82.8991.5579.173.30667.40
MAE [16]78.3188.6273.053.50360.32
SimMIM [43]79.9189.4771.393.46861.09
MultiMAE [3]80.5590.9174.523.42762.14
mc-BEI T [25]82.5991.7875.843.38863.61
AttMask [19]83.8092.3676.503.28564.77
MRM85.4693.1180.263.24570.15
+ +masking to capture the representation. The image feature is directly fed into the image decoder to reconstruct the image without multimodal fusion. As for the relation matching, only self-modality matching is employed for image features. Table 5 indicates that MRM exhibits the best transfer ability across four downstream tasks, verifying the effectiveness of MRM with single image modality pre-training. + +# 5. Broader Impact and Limitations + +The proposed MRM framework, consisting of relation masking and relation matching, can enable the model to capture relation information by token-wise feature masking and sample-wise global relation constraint, thereby learning better feature representation. Extensive experiments across various downstream diagnosis tasks demonstrate that the MRM has superior transfer ability over state-of-the-art methods, and it can also applies single image modality pretraining to achieve compelling performance. Moreover, in this work, we assume the data distribution between downstream datasets and the pre-training dataset is identical, and do not consider the issue of data domain shift. Hence, in future work, we will improve our framework towards data domain shift issue between pre-training dataset and various downstream datasets. + +# 6. Conclusion + +In this work, we present MRM framework to jointly leverage medical images and genetics for self-supervised pre-training. Instead of explicitly masking inputs, we design the relation masking to mask out feature relation and enable the model to capture informative patterns, which can retain intact disease-related semantics. Moreover, to enrich semantic relation, we present relation matching by exploiting inter-sample relation to encourage global constraints in the feature space. Extensive experiments verify the effectiveness of MRM on various downstream diagnosis tasks. + +# References + +[1] Aptos 2019 blindness detection. +https://www.kaggle.com/c/ + +aptos2019-blindnessdetection/ Accessed: 2021-11-04.6 +[2] Shekoofeh Azizi, Basil Mustafa, Fiona Ryan, Zachary Beaver, Jan Freyberg, Jonathan Deaton, Aaron Loh, Alan Karthikesalingam, Simon Kornblith, Ting Chen, et al. Big self-supervised models advance medical image classification. In Proc. ICCV, pages 3478-3488, 2021. 3 +[3] Roman Bachmann, David Mizrahi, Andrei Atanov, and Amir Zamir. Multimae: Multi-modal multi-task masked autoencoders. In Proc. ECCV, pages 348-367. Springer, 2022. 2, 3, 6, 7, 8, 9 +[4] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. Beit: Bert pre-training of image transformers. In Proc. ICLR, 2022. 1, 2, 3 +[5] Rodrigo Bonazzola, Nishant Ravikumar, Rahman Attar, Enzo Ferrante, Tanveer Syeda-Mahmood, and Alejandro F Frangi. Image-derived phenotype extraction for genetic discovery via unsupervised deep learning in cmr images. In Proc. MICCAI, pages 699-708. Springer, 2021. 1, 2, 3 +[6] Nathaniel Braman, Jacob WH Gordon, Emery T Goossens, Caleb Willis, Martin C Stumpe, and Jagadish Venkataraman. Deep orthogonal fusion: multimodal prognostic biomarker discovery integrating radiology, pathology, genomic, and clinical data. In Proc. MICCAI, pages 667-677. Springer, 2021. 1, 3 +[7] Richard J Chen, Ming Y Lu, Jingwen Wang, Drew FK Williamson, Scott J Rodig, Neal I Lindeman, and Faisal Mahmood. Pathomic fusion: an integrated framework for fusing histopathology and genomic features for cancer diagnosis and prognosis. IEEE TMI, 41(4):757-770, 2020. 2, 3 +[8] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning of visual representations. In ICML, 2020. 2, 3, 6, 7, 9 +[9] Ting Chen, Simon Kornblith, Kevin Swersky, Mohammad Norouzi, and Geoffrey Hinton. Big self-supervised models are strong semi-supervised learners. In NeurlPS, 2020. 2, 7, 8 +[10] Xiaokang Chen, Mingyu Ding, Xiaodi Wang, Ying Xin, Shentong Mo, Yunhao Wang, Shumin Han, Ping Luo, Gang Zeng, and Jingdong Wang. Context autoencoder for self-supervised representation learning. arXiv preprint arXiv:2202.03026, 2022. 2, 3 +[11] Xinlei Chen, Saining Xie, and Kaiming He. An empirical study of training self-supervised vision transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 9640-9649, 2021. 2, 7, 8 +[12] Zekai Chen, Devansh Agarwal, Kshitij Aggarwal, Wiem Safta, Mariann Micsinai Balan, and Kevin Brown. Masked image modeling advances 3d medical image analysis. In Proc. WACV, 2023. 1 +[13] Zhihong Chen, Yuhao Du, Jinpeng Hu, Yang Liu, Guanbin Li, Xiang Wan, and Tsung-Hui Chang. Multi-modal masked autoencoders for medical vision-and-language pre-training. In Proc. MICCAI, pages 679-689. Springer, 2022. 1, 3, 6, 7 +[14] Jacob Cohen. Weighted kappa: nominal scale agreement provision for scaled disagreement or partial credit. *Psychol Bull*, 70(4):213, 1968. 6 + +[15] Jean-Bastien Grill, Florian Strub, Florent Altché, Corentin Tallec, Pierre H Richemond, Elena Buchatskaya, Carl Doersch, Bernardo Avila Pires, Zhaohan Daniel Guo, Mohammad Gheshlaghi Azar, et al. Bootstrap your own latent: A new approach to self-supervised learning. In NeurIPS, 2020. 2, 3 +[16] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dólár, and Ross Girshick. Masked autoencoders are scalable vision learners. In Proc. CVPR, pages 16000-16009, 2022. 1, 2, 3, 6, 7, 8, 9 +[17] Kaiming He, Haoqi Fan, Yuxin Wu, Saining Xie, and Ross Girshick. Momentum contrast for unsupervised visual representation learning. In CVPR, 2020. 2, 3, 6, 9 +[18] Jose Ignacio Orlando Hrvoje Bogunovic Xu Sun Jingan Liao Yanwu Xu Shaochong Zhang Huazhu Fu, Fei Li and Xiulan Zhang. Palm: Pathologic myopia challenge. 2019. 6 +[19] Ioannis Kakogeorgiou, Spyros Gidaris, Bill Psomas, Yannis Avrithis, Andrei Bursuc, Konstantinos Karantzalos, and Nikos Komodakis. What to hide from your students: Attention-guided masked image modeling. In Proc. ECCV, pages 300-318. Springer, 2022. 2, 3, 6, 7, 8, 9 +[20] Jacob Devlin Ming-Wei Chang Kenton and Lee Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In Proc. NAACL, pages 4171–4186, 2019. 3 +[21] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. Proc. ICLR, 2015. 7 +[22] Günter Klambauer, Thomas Unterthiner, Andreas Mayr, and Sepp Hochreiter. Self-normalizing neural networks. In Proc. NeurIPS, volume 30, 2017. 4 +[23] Wuyang Li, Jie Liu, Bo Han, and Yixuan Yuan. Adjustment and alignment for unbiased open set domain adaptation. In Proc. CVPR, pages 24110-24119, 2023. 2 +[24] Wuyang Li, Xinyu Liu, and Yixuan Yuan. Sigma: Semantic-complete graph matching for domain adaptive object detection. In Proc. CVPR, pages 5291-5300, 2022. 2 +[25] Xiaotong Li, Yixiao Ge, Kun Yi, Zixuan Hu, Ying Shan, and Ling-Yu Duan. mc-beit: Multi-choice discretization for image bert pre-training. In Proc. ECCV, pages 231-246. Springer, 2022. 1, 2, 6, 7, 8, 9 +[26] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. Proc. ICLR, 2019. 7 +[27] Yang Luo, Zhineng Chen, and Xieping Gao. Self-distillation augmented masked autoencoders for histopathological image classification. arXiv preprint arXiv:2203.16983, 2022. 1, 3 +[28] Zhenyuan Ning, Denghui Du, Chao Tu, Qianjin Feng, and Yu Zhang. Relation-aware shared representation learning for cancer prognosis analysis with auxiliary clinical variables and incomplete multi-modality data. IEEE TMI, 41(1):186-198, 2021. 1, 2, 3 +[29] Samiksha Pachade, Prasanna Porwal, Dhanshree Thulkar, Manesh Kokare, Girish Deshmukh, Vivek Sahasrabuddhe, Luca Giancardo, Gwenolé Quellec, and Fabrice Mériaudeau. Retinal fundus multi-disease image dataset (rfmid): A dataset for multi-disease detection research. Data, 6(2):14, 2021. 6 + +[30] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, Luca Antiga, et al. Pytorch: An imperative style, high-performance deep learning library. In NeurIPS, 2019. 7 +[31] Ryan Poplin, Avinash V Varadarajan, Katy Blumer, Yun Liu, Michael V McConnell, Greg S Corrado, Lily Peng, and Dale R Webster. Prediction of cardiovascular risk factors from retinal fundus photographs via deep learning. Nat. Biomed. Eng., 2(3):158-164, 2018. 6 +[32] Yu Rong, Wenbing Huang, Tingyang Xu, and Junzhou Huang. Droppedge: Towards deep graph convolutional networks on node classification. In Proc. ICLR, 2020. 5 +[33] Hannah Spitzer, Kai Kiwitz, Katrin Amunts, Stefan Harmeling, and Timo Dickscheid. Improving cytoarchitectonic segmentation of human brain areas with self-supervised siamese networks. In Proc. MICCAI, pages 663-671. Springer, 2018. 6 +[34] Aiham Taleb, Matthias Kirchler, Remo Monti, and Christoph Lippert. Contig: Self-supervised multimodal contrastive learning for medical imaging with genetics. In Proc. CVPR, pages 20908-20921, 2022. 1, 3, 6, 7, 8, 9 +[35] Aiham Taleb, Christoph Lippert, Tassilo Klein, and Moin Nabi. Multimodal self-supervised learning for medical image analysis. In Proc. IPMI, pages 661-673. Springer, 2021. 1, 3 +[36] Aiham Taleb, Winfried Loetzsch, Noel Danz, Julius Severin, Thomas Gaertner, Benjamin Bergner, and Christoph Lippert. 3d self-supervised methods for medical imaging. Proc. NeurIPS, 33:18158-18172, 2020. 1, 3 +[37] Katarzyna Tomczak, Patrycja Czerwińska, and Maciej Wiznerowicz. Review the cancer genome atlas (tcga): an immeasurable source of knowledge. Contemp. Oncol., 2015(1):68-77, 2015. 7 +[38] Rami S Vanguri, Jia Luo, Andrew T Aukerman, Jacklynn V Egger, Christopher J Fong, Nataly Horvat, Andrew Pagano, Jose de Arimateia Batista Araujo-Filho, Luke Geneslaw, Hira Rizvi, et al. Multimodal integration of radiology, pathology and genomics for prediction of response to pd-(l) 1 blockade in patients with non-small cell lung cancer. Nature cancer, 3(10):1151-1164, 2022. 1, 3 +[39] Wenguan Wang, Tianfei Zhou, Fisher Yu, Jifeng Dai, Ender Konukoglu, and Luc Van Gool. Exploring cross-image pixel contrast for semantic segmentation. In Proc. ICCV, pages 7303-7313, 2021. 2 +[40] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In Proc. CVPR, pages 14668-14678, 2022. 2 +[41] LI Wuyang, YANG Chen, LIU Jie, LIU Xinyu, GUO Xiaqing, and YUAN Yixuan. Joint polyp detection and segmentation with heterogeneous endoscopic data. In Proc. ISBI Workshop, pages 69-79. CEUR-WS Team, 2021. 1 +[42] Junfei Xiao, Yutong Bai, Alan Yuille, and Zongwei Zhou. Delving into masked autoencoders for multi-label thorax disease classification. In Proc. WACV, pages 3588-3600, 2023. 1, 3 + +[43] Zhenda Xie, Zheng Zhang, Yue Cao, Yutong Lin, Jianmin Bao, Zhuliang Yao, Qi Dai, and Han Hu. Simmim: A simple framework for masked image modeling. In Proc. CVPR, pages 9653-9663, 2022. 1, 2, 3, 6, 7, 8, 9 +[44] Xiaohan Xing, Zhen Chen, Meilu Zhu, Yuenan Hou, Zhifan Gao, and Yixuan Yuan. Discrepancy and gradient-guided multi-modal knowledge distillation for pathological glioma grading. In Proc. MICCAI, pages 636-646. Springer, 2022. 1, 3, 7 +[45] Qiushi Yang, Xiaqing Guo, Zhen Chen, Peter YM Woo, and Yixuan Yuan. D2-net: Dual disentanglement network for brain tumor segmentation with missing modalities. IEEE TMI, 41(10):2953-2964, 2022. 1 +[46] Qiushi Yang and Yixuan Yuan. Learning dynamic convolutions for multi-modal 3d mri brain tumor segmentation. In Brainlesion: MICCAI Workshop, pages 441-451. Springer, 2021. 1 +[47] Zhuoning Yuan, Yan Yan, Milan Sonka, and Tianbao Yang. Large-scale robust deep auc maximization: A new surrogate loss and empirical studies on medical image classification. In Proc. ICCV, pages 3040-3049, 2021. 1 +[48] Jinghao Zhou, Chen Wei, Huiyu Wang, Wei Shen, Cihang Xie, Alan Yuille, and Tao Kong. Image bert pre-training with online tokenizer. In Proc. ICLR, 2022. 2, 3 +[49] Lei Zhou, Huidong Liu, Joseph Bae, Junjun He, Dimitris Samaras, and Prateek Prasanna. Self pre-training with masked autoencoders for medical image analysis. arXiv preprint arXiv:2203.05573, 2022. 1, 3 \ No newline at end of file diff --git a/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/images.zip b/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..913452ab1b6938dd9e254659f1c8c9e79cdb84f9 --- /dev/null +++ b/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:311c738be0a91fdf486fce157ddbb0049858e0b45585ef7941527c7cd3ac4dd1 +size 491339 diff --git a/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/layout.json b/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..650d5b888ac303a9a50d7b240b712bf3fa89f1da --- /dev/null +++ b/2023/MRM_ Masked Relation Modeling for Medical Image Pre-Training with Genetics/layout.json @@ -0,0 +1,10419 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 47, + 103, + 547, + 122 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 103, + 547, + 122 + ], + "spans": [ + { + "bbox": [ + 47, + 103, + 547, + 122 + ], + "type": "text", + "content": "MRM: Masked Relation Modeling for Medical Image Pre-Training with Genetics" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 138, + 142, + 206, + 158 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 138, + 142, + 206, + 158 + ], + "spans": [ + { + "bbox": [ + 138, + 142, + 206, + 158 + ], + "type": "text", + "content": "Qiushi Yang" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 228, + 143, + 288, + 157 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 228, + 143, + 288, + 157 + ], + "spans": [ + { + "bbox": [ + 228, + 143, + 288, + 157 + ], + "type": "text", + "content": "Wuyang Li" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 313, + 143, + 365, + 157 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 313, + 143, + 365, + 157 + ], + "spans": [ + { + "bbox": [ + 313, + 143, + 365, + 157 + ], + "type": "text", + "content": "Baopu Li3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 390, + 143, + 469, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 390, + 143, + 469, + 156 + ], + "spans": [ + { + "bbox": [ + 390, + 143, + 469, + 156 + ], + "type": "text", + "content": "Yixuan Yuan" + }, + { + "bbox": [ + 390, + 143, + 469, + 156 + ], + "type": "inline_equation", + "content": "^{1,2*}" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 121, + 159, + 484, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 121, + 159, + 484, + 171 + ], + "spans": [ + { + "bbox": [ + 121, + 159, + 484, + 171 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 121, + 159, + 484, + 171 + ], + "type": "text", + "content": "City University of Hong Kong " + }, + { + "bbox": [ + 121, + 159, + 484, + 171 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 121, + 159, + 484, + 171 + ], + "type": "text", + "content": "The Chinese University of Hong Kong " + }, + { + "bbox": [ + 121, + 159, + 484, + 171 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 121, + 159, + 484, + 171 + ], + "type": "text", + "content": "Independent Researcher" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 55, + 174, + 276, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 174, + 276, + 185 + ], + "spans": [ + { + "bbox": [ + 55, + 174, + 276, + 185 + ], + "type": "text", + "content": "{qsyang2-c, wuyangli2-c}@my.cityu.edu.hk." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 311, + 174, + 417, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 174, + 417, + 185 + ], + "spans": [ + { + "bbox": [ + 311, + 174, + 417, + 185 + ], + "type": "text", + "content": "bpliu.cuhk@gmail.com" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 436, + 175, + 551, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 436, + 175, + 551, + 185 + ], + "spans": [ + { + "bbox": [ + 436, + 175, + 551, + 185 + ], + "type": "text", + "content": "yxyuan@ee.cuhk.edu.hk" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "spans": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 238, + 290, + 574 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 238, + 290, + 574 + ], + "spans": [ + { + "bbox": [ + 46, + 238, + 290, + 574 + ], + "type": "text", + "content": "Modern deep learning techniques on automatic multimodal medical diagnosis rely on massive expert annotations, which is time-consuming and prohibitive. Recent masked image modeling (MIM)-based pre-training methods have witnessed impressive advances for learning meaningful representations from unlabeled data and transferring to downstream tasks. However, these methods focus on natural images and ignore the specific properties of medical data, yielding unsatisfying generalization performance on downstream medical diagnosis. In this paper, we aim to leverage genetics to boost image pre-training and present a masked relation modeling (MRM) framework. Instead of explicitly masking input data in previous MIM methods leading to loss of disease-related semantics, we design relation masking to mask out token-wise feature relation in both self- and cross-modality levels, which preserves intact semantics within the input and allows the model to learn rich disease-related information. Moreover, to enhance semantic relation modeling, we propose relation matching to align the sample-wise relation between the intact and masked features. The relation matching exploits inter-sample relation by encouraging global constraints in the feature space to render sufficient semantic relation for feature representation. Extensive experiments demonstrate that the proposed framework is simple yet powerful, achieving state-of-the-art transfer performance on various downstream diagnosis tasks. Codes are available at https://github.com/CityU-AIM-Group/MRM." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 47, + 597, + 128, + 609 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 597, + 128, + 609 + ], + "spans": [ + { + "bbox": [ + 47, + 597, + 128, + 609 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 617, + 287, + 666 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 287, + 666 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 287, + 666 + ], + "type": "text", + "content": "In the medical diagnosis [44, 34, 38, 28, 6, 5], the largescale multimodal biobank data, e.g., images and genetics, is necessary for a reliable diagnosis, overcoming the limited scale and disease information of a single-modality" + } + ] + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 310, + 217, + 427, + 282 + ], + "blocks": [ + { + "bbox": [ + 310, + 217, + 427, + 282 + ], + "lines": [ + { + "bbox": [ + 310, + 217, + 427, + 282 + ], + "spans": [ + { + "bbox": [ + 310, + 217, + 427, + 282 + ], + "type": "image", + "image_path": "6b0ce549fceda1ce6a9605b5b97bcd214d2b76ee6e91b598128d86a8e9eacd0a.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 427, + 219, + 543, + 282 + ], + "blocks": [ + { + "bbox": [ + 427, + 219, + 543, + 282 + ], + "lines": [ + { + "bbox": [ + 427, + 219, + 543, + 282 + ], + "spans": [ + { + "bbox": [ + 427, + 219, + 543, + 282 + ], + "type": "image", + "image_path": "f18ab18d9d702730946f58a822f9406fb304a8098ba1f0589b24879b8a0ce28a.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 310, + 284, + 427, + 351 + ], + "blocks": [ + { + "bbox": [ + 310, + 284, + 427, + 351 + ], + "lines": [ + { + "bbox": [ + 310, + 284, + 427, + 351 + ], + "spans": [ + { + "bbox": [ + 310, + 284, + 427, + 351 + ], + "type": "image", + "image_path": "3f1dd1d615c93a1dbd8d2feea6c1614cf1c70b5e9e079b9198c166c2c3756294.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 361, + 547, + 483 + ], + "lines": [ + { + "bbox": [ + 304, + 361, + 547, + 483 + ], + "spans": [ + { + "bbox": [ + 304, + 361, + 547, + 483 + ], + "type": "text", + "content": "Figure 1. Comparison of different masking strategies on natural and medical data. (a): Existing MIM methods mask out input natural images and infer the missing content to learn semantic representations via reconstruction task. (b): Recent pre-training approaches for disease diagnosis explicitly employ MIM on input medical data (e.g., medical images and genome), whilst they are prone to lose tiny disease regions and cause non-tractable reconstruction. (c): Our method masks token-wise feature relation across multimodal data and matches sample-wise relation between the intact and masked features, preserving intact semantic regions and enriching relation information." + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 427, + 285, + 543, + 351 + ], + "blocks": [ + { + "bbox": [ + 427, + 285, + 543, + 351 + ], + "lines": [ + { + "bbox": [ + 427, + 285, + 543, + 351 + ], + "spans": [ + { + "bbox": [ + 427, + 285, + 543, + 351 + ], + "type": "image", + "image_path": "85c3242344fc994459dc4baa0aa4f84e019cb7b0548b4c6e11a08ea5b156c504.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 507, + 547, + 581 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 507, + 547, + 581 + ], + "spans": [ + { + "bbox": [ + 304, + 507, + 547, + 581 + ], + "type": "text", + "content": "dataset. However, the prohibitive expert annotations of large-scale datasets make it difficult to train a conventional deep model [44, 45, 41, 46, 47]. Particularly, in this multimodal scenario, the requirements of the experts in various medical fields prevent enough annotation access, severely limiting the grounding of the automatic diagnosis system." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 582, + 548, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 548, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 548, + 714 + ], + "type": "text", + "content": "To address this, the most prospering trend [16, 43, 4, 34, 13, 35, 36, 12, 27] is self-supervised pre-training, e.g., masked image modeling (MIM) [16, 43, 13, 42], aiming to train a label-free model with adequate generalization capacity. Existing MIM methods [16, 43, 4, 25, 13, 42, 49] mask out a high portion of patches within input images and infer the missing content, as suggested in Figure 1 (a). They make use of contextual information to glance the semantics and reconstruct the entire images, which performs a mask-and-reconstruct task to pre-train the model without annotation and transfer meaningful representations to various" + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 674, + 136, + 684 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 674, + 136, + 684 + ], + "spans": [ + { + "bbox": [ + 58, + 674, + 136, + 684 + ], + "type": "text", + "content": "*Corresponding author." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 47, + 684, + 287, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 684, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 684, + 287, + 713 + ], + "type": "text", + "content": "This work was supported by Hong Kong Research Grants Council (RGC) General Research Fund 14220622, 14204321, and Innovation and Technology Commission-Innovation and Technology Fund ITS/100/20." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "21452" + } + ] + } + ], + "index": 25 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 285, + 83 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 285, + 83 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 285, + 83 + ], + "type": "text", + "content": "downstream tasks for improving label-efficient fine-tuning." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 87, + 287, + 422 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 87, + 287, + 422 + ], + "spans": [ + { + "bbox": [ + 46, + 87, + 287, + 422 + ], + "type": "text", + "content": "Though achieving great success, most works [16, 43, 4, 40, 10, 25, 19] are designed for natural images, ignoring the essential differences between medical data and natural images. Therefore, we empirically find that existing MIM CANNOT works well in medical data (see Table 1), and even totally fails to reconstruct diseases (see Figure 3). The reasons derive from a critical observation regarding the significant data differences, which can be summarized into two challenges. Firstly, compared with natural images, there are limited semantic regions in medical data. As shown in Figure 1 (a), the semantic-rich foreground is always the main body of the natural image, while the rest non-informative background region only represents a minority part. Differently, in the medical image (Figure 1 (b)), the majority of regions are backgrounds, and the informative disease regions are usually on a tiny scale. Under the strategy of masking entire tokens in existing MIM methods [16, 43, 4, 40, 10, 25, 19], if the disease tokens are masked out, the disease-related semantic is totally missing with a catastrophic information loss, leading to a nontractable reconstruction. This issue also exists between genomics and natural images. The semantic regions in genomics, i.e., the disease-related patterns, mainly lie in a minority of genome segments [28, 5, 7]. Hence, instead of masking the whole input token, these observations motivate us to delve into the masking of token-level relation, which preserves abundant semantic discriminability and adequate self-supervision, as illustrated in Figure 1 (c) Left." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 424, + 287, + 663 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 424, + 287, + 663 + ], + "spans": [ + { + "bbox": [ + 46, + 424, + 287, + 663 + ], + "type": "text", + "content": "The second challenge is the limited semantic relation. In a natural image, the background and foreground relationship, e.g., the bird in the sky and the person in a room, tends to be prosperous and abundant, serving a critical role in semantic-level learning [39, 24]. In contrast, in each medical data sample, the disease-aware relation is limited and insufficient to provide enough discriminative evidence. The reason lies in that the medical datasets are usually collected from the same human organ, e.g., the fundus, containing redundant and similar anatomical patterns, e.g., the capillary, which severely prevent the relation modeling between the disease and the complex medical scene. This challenge hampers reliable relation learning in existing MIM methods, and may incur an inevitable overfitting to noninformative relation within the background [40, 25, 23, 3]. Hence, considering the limited semantic relation in each data sample, we are committed to going beyond the self-supervised learning for an independent and individual data sample, and propose to encourage global constraints for exploiting inter-sample relation (see Figure 1 (c) Right)." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "type": "text", + "content": "To combat above challenges, as shown in Figure 1 (c), we present MRM, a masked relation modeling from a unified view of relation, containing relation masking and relation matching, to rationally pre-train multimodal medical" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 304, + 72, + 545, + 334 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 334 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 334 + ], + "type": "text", + "content": "images with genetics. To preserve intact semantic information within raw input, we devise relation masking strategy to allow the model to learn disease-related semantics. Instead of masking out input data, the relation masking investigates token-wise relation within feature representations in both self- and cross-modality levels and masks out the relation among all multimodal tokens. The relation masking endows the model to explicitly learn global dependency from raw data without missing disease-related semantic information. Furthermore, to improve the semantic relation modeling, the relation matching is designed to provide global constraint by aligning the feature relation across multiple samples. Specifically, relation matching exploits sample-wise relation in both self- and cross-modality levels to encourage the relation consistency between the intact and masked features. This enjoys the complementary advantages of persample pixel-wise reconstruction loss and boosts the transfer ability of the model. With the pre-trained model, we can obtain the feature representation that can be transferred to supervised downstream diagnosis tasks for boosting label-efficient fine-tuning, alleviating the severe demand for specialized annotations." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 317, + 336, + 518, + 348 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 336, + 518, + 348 + ], + "spans": [ + { + "bbox": [ + 317, + 336, + 518, + 348 + ], + "type": "text", + "content": "In summary, our contributions fall into four parts:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 317, + 357, + 545, + 616 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 317, + 357, + 545, + 405 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 357, + 545, + 405 + ], + "spans": [ + { + "bbox": [ + 317, + 357, + 545, + 405 + ], + "type": "text", + "content": "- We identify the challenges of current MIM methods on medical data, and present MRM, a masked relation modeling using multimodal medical data to facilitate image representation learning." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 415, + 545, + 487 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 415, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 317, + 415, + 545, + 487 + ], + "type": "text", + "content": "- Towards the issue of limited semantic regions in medical data, we design relation masking to mask tokenwise feature relation across self- and cross-modality. Different from MIM explicitly masking inputs, relation masking preserves disease semantics within inputs, endowing a powerful mask-and-construct task." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 498, + 545, + 558 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 498, + 545, + 558 + ], + "spans": [ + { + "bbox": [ + 317, + 498, + 545, + 558 + ], + "type": "text", + "content": "- Moreover, to enrich the semantic relation among diseases, the relation matching is proposed to capture abundant disease-related relation by aligning sample-wise feature relation between intact and masked features in both self- and cross-modality levels." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 317, + 568, + 545, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 568, + 545, + 616 + ], + "spans": [ + { + "bbox": [ + 317, + 568, + 545, + 616 + ], + "type": "text", + "content": "- Extensive transfer evaluation on various downstream tasks using two public medical pre-training datasets demonstrate that our framework performs superior transfer ability over state-of-the-art methods." + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 638, + 392, + 651 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 638, + 392, + 651 + ], + "spans": [ + { + "bbox": [ + 306, + 638, + 392, + 651 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 658, + 419, + 671 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 658, + 419, + 671 + ], + "spans": [ + { + "bbox": [ + 306, + 658, + 419, + 671 + ], + "type": "text", + "content": "2.1. Visual Pre-training" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 677, + 545, + 713 + ], + "type": "text", + "content": "In recent years, self-supervised visual pre-training [8, 9, 15, 17, 11, 16, 43, 48, 4] has achieved exceptional transfer performance in various downstream visual tasks, which" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "21453" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 76, + 542, + 262 + ], + "blocks": [ + { + "bbox": [ + 51, + 76, + 542, + 262 + ], + "lines": [ + { + "bbox": [ + 51, + 76, + 542, + 262 + ], + "spans": [ + { + "bbox": [ + 51, + 76, + 542, + 262 + ], + "type": "image", + "image_path": "3b4916f3987b8ea0e696a6ff15de0887dc8eb89915e6fe6b20443e8b644423d6.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 277, + 546, + 301 + ], + "lines": [ + { + "bbox": [ + 46, + 277, + 546, + 301 + ], + "spans": [ + { + "bbox": [ + 46, + 277, + 546, + 301 + ], + "type": "text", + "content": "Figure 2. Overview of masked relation modeling (MRM). MRM contains relation masking to mask out token-wise feature relation with preserving disease-related semantics, and the relation matching to enforce sample-wise relation consistency for global semantic modeling." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 320, + 289, + 559 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 320, + 289, + 559 + ], + "spans": [ + { + "bbox": [ + 46, + 320, + 289, + 559 + ], + "type": "text", + "content": "can be divided into two categories. The first is contrastive-based methods [8, 15, 17, 35, 35] that aim to project similar samples nearby while pull dissimilar ones far away in the feature space. For instance, SimCLR [8] imposes two embeddings from a sample under different views consistency via InfoNCE loss, and BYOL [15] merely pushes the positive pairs together with a momentum encoder for boosting transfer performance. Moreover, inspired by the progress of masked language modeling on natural language processing [20], masked image modeling (MIM)-based approaches [16, 48, 43, 4, 3, 10, 3] are proposed to pre-train visual models and exhibit remarkable transfer performance. MAE [16] formulates a pixel-wise reconstruction task to mask out a high portion of input patches and infer the masked ones with visible tokens via an autoencoder. Afterwards, many followups [43, 3, 19, 10] devise MIM models to improve the representation learning. However, they mainly focus on natural images and ignore the essential differences between the medical data and natural images, thereby delivering unsatisfying transfer results [27, 49]." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 573, + 228, + 586 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 573, + 228, + 586 + ], + "spans": [ + { + "bbox": [ + 47, + 573, + 228, + 586 + ], + "type": "text", + "content": "2.2. Medical Self-supervised Learning" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 594, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 287, + 713 + ], + "type": "text", + "content": "Most works [35, 36, 2, 34] on medical self-supervised learning extend the ideas of contrastive learning and develop customized strategies to pre-train models. 3DSSL [36] adopt a series of proxy tasks to present a 3D versions self-supervised model and achieves compelling transfer results. ContIG [34] crafts a multimodal pre-training framework using image and genome data via contrastive learning and delivers competitive transfer ability. Although efficiency, these contrastive-based approaches strongly rely on well-defined data augmentations to construct positive" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 320, + 545, + 476 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 320, + 545, + 476 + ], + "spans": [ + { + "bbox": [ + 304, + 320, + 545, + 476 + ], + "type": "text", + "content": "pairs, which are difficult for medical data, especially for structured data, e.g., genetics. Most recently, some studies [13, 42, 27, 49] adopt MIM to self-supervised pre-train medical models. MedicalMAE [49] introduces a self pretraining paradigm by employing MAE [16] to pre-train the model and achieve superior performance. To perform multimodal pre-training, " + }, + { + "bbox": [ + 304, + 320, + 545, + 476 + ], + "type": "inline_equation", + "content": "\\mathrm{M}^{3}\\mathrm{3AE}" + }, + { + "bbox": [ + 304, + 320, + 545, + 476 + ], + "type": "text", + "content": " [13] randomly masks out the tokens of image and language inputs and aims to infer the whole data using visible tokens. All of them still adopt input masking strategy, which may incur tiny disease-related region missing and non-tractable reconstruction. Differently, we design a novel relation masking strategy in the feature space and retain intact disease-related information." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 498, + 497, + 511 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 498, + 497, + 511 + ], + "spans": [ + { + "bbox": [ + 306, + 498, + 497, + 511 + ], + "type": "text", + "content": "2.3. Learning from Images and Genetics" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 522, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 522, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 522, + 545, + 713 + ], + "type": "text", + "content": "Genetics can provide comprehensive information for many disease diagnosis and treatment planning [38, 28, 6, 5, 7], which attract much attention from researchers. Many works [44, 34, 38] formulate a multimodal learning task by jointly leveraging genetics and medical images to exploit complementary knowledge. Considering that the genetics may be difficult to acquire in many clinical applications, recent studies [34, 7] aim to design pre-training models using images and genetics for improving practical image-based diagnosis. However, they merely use contrastive constraint to perform self-supervised learning, while they fail to adopt the efficient mask-and-reconstruct task to pre-train models. In this work, we aim to leverage genetics with images to boost the visual representation learning via semantic relation modeling, which discovers both inner-sample and intersample relation to achieve more effective pre-training." + } + ] + } + ], + "index": 7 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "text", + "content": "21454" + } + ] + } + ], + "index": 8 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 71, + 201, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 71, + 201, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 71, + 201, + 85 + ], + "type": "text", + "content": "3. Masked Relation Modeling" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 91, + 287, + 163 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 91, + 287, + 163 + ], + "spans": [ + { + "bbox": [ + 46, + 91, + 287, + 163 + ], + "type": "text", + "content": "In this section, we start by introducing the preliminaries of vision Transformer and masked image modeling. We then present the masked relation modeling (MRM), containing relation masking and relation matching. The overall pre-training and transfer inference of the framework are described at the end of the section." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 170, + 133, + 182 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 170, + 133, + 182 + ], + "spans": [ + { + "bbox": [ + 47, + 170, + 133, + 182 + ], + "type": "text", + "content": "3.1. Preliminaries" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "spans": [ + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "text", + "content": "Vision Transformer (ViT). Given an image " + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "inline_equation", + "content": "x \\in \\mathbb{R}^{c \\times h \\times w}" + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "text", + "content": ", ViT first splits it into " + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "inline_equation", + "content": "n = hw / p^2" + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "text", + "content": " non-overlapping patches " + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "inline_equation", + "content": "x_P = \\{x_1; x_2; \\ldots; x_n\\}" + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "inline_equation", + "content": "x_i \\in \\mathbb{R}^{c \\times p \\times p}" + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "inline_equation", + "content": "p \\times p" + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "text", + "content": " denotes the size of each patch. Afterwards, the patches " + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "inline_equation", + "content": "x_P" + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "text", + "content": " are tokenized as a sequence of token embeddings " + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "inline_equation", + "content": "e = \\{e_1; e_2; \\ldots; e_n\\}" + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "inline_equation", + "content": "e_i \\in \\mathbb{R}^{1 \\times d}" + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "text", + "content": " is the dimension of each token, via a linear projection with positional embeddings. The embeddings " + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "inline_equation", + "content": "e" + }, + { + "bbox": [ + 46, + 188, + 288, + 308 + ], + "type": "text", + "content": " are then processed by a cascade of multi-head self-attention layers to capture global information, where the self-attention is described as follow:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 88, + 315, + 287, + 340 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 88, + 315, + 287, + 340 + ], + "spans": [ + { + "bbox": [ + 88, + 315, + 287, + 340 + ], + "type": "interline_equation", + "content": "\\operatorname {A t t e n t i o n} (e) = \\operatorname {S o f t m a x} \\left(\\frac {1}{\\sqrt {d}} Q K ^ {T}\\right) V, \\tag {1}", + "image_path": "d718f2a3ad938771beb8234082ecdeda6b475a8514373bd9ca9d82f1a1c57f16.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "spans": [ + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "type": "inline_equation", + "content": "K = eW^{K}" + }, + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "type": "inline_equation", + "content": "Q = eW^{Q}" + }, + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "type": "inline_equation", + "content": "V = eW^{V}" + }, + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "type": "inline_equation", + "content": "K, Q, V \\in \\mathbb{R}^{1 \\times d}" + }, + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "type": "text", + "content": " is the key, query and value obtained by the linear projection via " + }, + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "type": "inline_equation", + "content": "W^{K}, W^{Q}, W^{V}" + }, + { + "bbox": [ + 46, + 347, + 287, + 419 + ], + "type": "text", + "content": ", respectively. Each layer of the ViT encoder contains a multi-head self-attention block, and the feature representation is produced by multiple layers within the encoder." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "spans": [ + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "text", + "content": "Masked Image Modeling (MIM). The input patches " + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "inline_equation", + "content": "x_{p}" + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "text", + "content": " are randomly masked out with a high ratio, denoted as masked patches " + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "inline_equation", + "content": "x_{M}" + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "text", + "content": ". The remaining visible patches " + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "inline_equation", + "content": "x_{V}" + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "text", + "content": " are fed into ViT encoder " + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "inline_equation", + "content": "f(\\cdot)" + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "text", + "content": " to capture features " + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "inline_equation", + "content": "z = f(x_{V})" + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "text", + "content": ", which are then sent to a lightweight decoder " + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "inline_equation", + "content": "h(\\cdot)" + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "text", + "content": " to recover the missing patches " + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\hat{x} = h(z)" + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "text", + "content": " of the input data. The overall framework is optimized by mean-squared error (MSE) reconstruction loss function " + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{MIM}}" + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "text", + "content": " between the recovered patches " + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\hat{x}" + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "text", + "content": " and masked patches " + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "inline_equation", + "content": "x_{M}" + }, + { + "bbox": [ + 46, + 420, + 287, + 529 + ], + "type": "text", + "content": " as:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 102, + 536, + 287, + 550 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 102, + 536, + 287, + 550 + ], + "spans": [ + { + "bbox": [ + 102, + 536, + 287, + 550 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {M I M}} = \\mathbb {E} | | x _ {M} - h (f (x _ {V})) | | _ {2} ^ {2}. \\tag {2}", + "image_path": "ecde227234db1c90b73668b2d3dd1a6d28671df656e76a1703a663b2ddccdf23.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "content": "Overview of Masked Relation Modeling (MRM). As illustrated in Figure 2, the proposed MRM consists of the relation masking strategy to mask out feature relation and preserve intact disease-related semantics, and the relation matching to offer global constraints for relation modeling. With the input image " + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "inline_equation", + "content": "x_{I}" + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "content": " and genome " + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "inline_equation", + "content": "x_{G}" + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "content": ", the ViT encoder " + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "inline_equation", + "content": "f_{I}" + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "content": " and self-normalizing network (SNN) [22] " + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "inline_equation", + "content": "f_{G}" + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "content": " produces masked feature representations " + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "inline_equation", + "content": "z_{I,M},z_{G,M}" + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "content": " for image and genome via relation masking. Parallely, the intact representations " + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "inline_equation", + "content": "z_{I},z_{G}" + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "content": " are obtained by two encoders without relation masking. Afterwards, the masked features " + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "inline_equation", + "content": "z_{I,M},z_{G,M}" + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "content": " are aggregated with the intact features " + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "inline_equation", + "content": "z_{G},z_{I}" + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "content": " from the other modality to yield the fused features " + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "inline_equation", + "content": "z_{I}^{F},z_{G}^{F}" + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "content": ", respectively." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "content": "These fused feature are then put into the image decoder " + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "inline_equation", + "content": "h_I" + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "content": " and the genome decoder " + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "inline_equation", + "content": "h_G" + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "content": " to reconstruct original data " + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "inline_equation", + "content": "\\hat{x}_I" + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "inline_equation", + "content": "\\hat{x}_G" + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "content": ". The relation matching is employed on intact and masked feature representations with the data reconstruction loss to jointly optimize the overall framework." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 137, + 411, + 150 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 137, + 411, + 150 + ], + "spans": [ + { + "bbox": [ + 306, + 137, + 411, + 150 + ], + "type": "text", + "content": "3.2. Relation Masking" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 156, + 545, + 275 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 156, + 545, + 275 + ], + "spans": [ + { + "bbox": [ + 304, + 156, + 545, + 275 + ], + "type": "text", + "content": "Due to the medical data usually appearing tiny disease patterns, current input-level masking strategies may discard disease-related semantics and hardly learn informative feature representation. To address this problem, the relation masking is proposed to mask token-wise feature relation from self- and cross-modality perspectives in a cascading manner, which can maintain intact input disease-related information during pre-training. The operations of relation masking for image and genome are parallel, for brevity, we adopt the image branch to introduce." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "spans": [ + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "type": "text", + "content": "Self-modality relation masking. In the " + }, + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "type": "text", + "content": "-th relation masking block, given " + }, + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "type": "inline_equation", + "content": "z_{I}^{0}" + }, + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "type": "text", + "content": " as the input image token, we first calculate " + }, + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "type": "inline_equation", + "content": "K_{I}^{S}, Q_{I}^{S}, V_{I}^{S}" + }, + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "type": "text", + "content": " as its key, query and value, respectively. Then, the normalized feature dependency in tokens is obtained by computing the relation between the key " + }, + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "type": "inline_equation", + "content": "K_{I}^{S}" + }, + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "type": "text", + "content": " and query " + }, + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "type": "inline_equation", + "content": "Q_{I}^{S}" + }, + { + "bbox": [ + 304, + 275, + 545, + 348 + ], + "type": "text", + "content": " of the image feature as follows:" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 353, + 352, + 545, + 377 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 353, + 352, + 545, + 377 + ], + "spans": [ + { + "bbox": [ + 353, + 352, + 545, + 377 + ], + "type": "interline_equation", + "content": "R _ {\\text {s e l f}} = \\operatorname {S o f t m a x} \\left(\\frac {1}{\\sqrt {d}} Q _ {I} ^ {S} \\cdot \\left(K _ {I} ^ {S}\\right) ^ {T}\\right). \\tag {3}", + "image_path": "6579b34a8f7e04a0ac24b4e5a33e308ea61337786a8500b5e3b92647078ec6d2.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 380, + 545, + 488 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 380, + 545, + 488 + ], + "spans": [ + { + "bbox": [ + 304, + 380, + 545, + 488 + ], + "type": "text", + "content": "This self-modality relation " + }, + { + "bbox": [ + 304, + 380, + 545, + 488 + ], + "type": "inline_equation", + "content": "R_{\\mathrm{self}}" + }, + { + "bbox": [ + 304, + 380, + 545, + 488 + ], + "type": "text", + "content": " reflects the token-wise semantic correspondence within the image feature. The tokens with stronger relation contain more interactive and informative semantics. To enable the model to capture intramodality feature representation via the reconstruction task, on the top of self-modality relation, we aim to break the strong dependency across informative regions by relation masking. Specifically, we mask out high-intensity elements with a ratio " + }, + { + "bbox": [ + 304, + 380, + 545, + 488 + ], + "type": "inline_equation", + "content": "\\tau_I" + }, + { + "bbox": [ + 304, + 380, + 545, + 488 + ], + "type": "text", + "content": " in self-modality relation:" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 321, + 491, + 545, + 518 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 321, + 491, + 545, + 518 + ], + "spans": [ + { + "bbox": [ + 321, + 491, + 545, + 518 + ], + "type": "interline_equation", + "content": "R _ {\\text {s e l f}} ^ {M} [ p, q ] = \\left\\{ \\begin{array}{c c} R _ {\\text {s e l f}} [ p, q ] & \\text {i f} R _ {\\text {s e l f}} [ p, q ] < r _ {\\text {s e l f}} ^ {p} \\\\ 0 & \\text {e l s e ,} \\end{array} \\right. \\tag {4}", + "image_path": "9055319b4a16b3c53e45e002538561351ae00f04d582257236f82b3dfceca0be.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "inline_equation", + "content": "r_{\\mathrm{self}}^p" + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "text", + "content": " refers to the intensity of the top-" + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "inline_equation", + "content": "\\tau_I" + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "text", + "content": " element among the " + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "text", + "content": "-th row of the self-modality relation " + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "inline_equation", + "content": "R_{\\mathrm{self}}" + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "text", + "content": " matrix. Note that the masked elements are selected in each row of the self-modality relation matrix to remove the semantic correspondence for all tokens with the same intensity. Afterwards, the masked relation matrix " + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "inline_equation", + "content": "R_{\\mathrm{self}}^M" + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "text", + "content": " is forwarded to produce the token " + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "inline_equation", + "content": "z_I^S = R_{\\mathrm{self}}^M V_I^S" + }, + { + "bbox": [ + 304, + 521, + 545, + 665 + ], + "type": "text", + "content": " for subsequent data flow. With the self-modality relation masking, the relative important dependency within the modality is discarded and we enforce the model to reconstruct the original image with the remaining weak feature relation. Thus, the model can capture disease-related feature representation of images." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "Cross-modality relation masking. In an attempt to incorporate multimodal knowledge, after the self-modality self-attention layer, we perform cross-modality attention between the image and genome features. Precisely, obtained" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "21455" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": "the image and genome tokens " + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "z_{I}^{S},z_{G}^{S}" + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": " masked via selfmodality relation masking, we compute token-wise crossmodality relation to capture semantic correspondence between image and genome features:" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 91, + 129, + 287, + 156 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 129, + 287, + 156 + ], + "spans": [ + { + "bbox": [ + 91, + 129, + 287, + 156 + ], + "type": "interline_equation", + "content": "R _ {\\text {c r o s s}} = \\operatorname {S o f t m a x} \\left(\\frac {1}{\\sqrt {d}} Q _ {I} ^ {C} \\cdot \\left(K _ {G} ^ {C}\\right) ^ {T}\\right), \\tag {5}", + "image_path": "367b7410290fd71474ea2d05faa4b237d1f01e2baa630f74c4f9d5eeaec98461.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 165, + 288, + 284 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 165, + 288, + 284 + ], + "spans": [ + { + "bbox": [ + 46, + 165, + 288, + 284 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 165, + 288, + 284 + ], + "type": "inline_equation", + "content": "K_{G}^{C}" + }, + { + "bbox": [ + 46, + 165, + 288, + 284 + ], + "type": "text", + "content": " means the key of genome feature " + }, + { + "bbox": [ + 46, + 165, + 288, + 284 + ], + "type": "inline_equation", + "content": "z_{G}^{S}" + }, + { + "bbox": [ + 46, + 165, + 288, + 284 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 165, + 288, + 284 + ], + "type": "inline_equation", + "content": "Q_{I}^{C}" + }, + { + "bbox": [ + 46, + 165, + 288, + 284 + ], + "type": "text", + "content": " represents the query of image feature " + }, + { + "bbox": [ + 46, + 165, + 288, + 284 + ], + "type": "inline_equation", + "content": "z_{I}^{S}" + }, + { + "bbox": [ + 46, + 165, + 288, + 284 + ], + "type": "text", + "content": " in the cross-attention layer. This cross-modality attention can amalgamate two modality knowledge and improve the feature representation towards disease-related information. Then, to allow the model to learn complementary multimodal knowledge and the relation between two modalities, we perform cross-modality relation masking by removing strong semantic correspondence between image and genome features:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 293, + 287, + 320 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 293, + 287, + 320 + ], + "spans": [ + { + "bbox": [ + 53, + 293, + 287, + 320 + ], + "type": "interline_equation", + "content": "R _ {\\text {c r o s s}} ^ {M} [ p, q ] = \\left\\{ \\begin{array}{c l} R _ {\\text {c r o s s}} [ p, q ] & \\text {i f} R _ {\\text {c r o s s}} [ p, q ] < r _ {\\text {c r o s s}} ^ {p} \\\\ 0 & \\text {e l s e ,} \\end{array} \\right. \\tag {6}", + "image_path": "4770df6fb4f3cb4fb05943dab3be74938ef132c51e31e19798a3e6971d747236.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "spans": [ + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "inline_equation", + "content": "r_{\\mathrm{cross}}^p" + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "text", + "content": " denotes the intensity of the top-" + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "inline_equation", + "content": "\\tau_I" + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "text", + "content": " element among the " + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "text", + "content": "-th row of the cross-modality relation matrix " + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "inline_equation", + "content": "R_{\\mathrm{cross}}" + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "text", + "content": ". With the masked relation " + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "inline_equation", + "content": "R_{\\mathrm{cross}}^M" + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "text", + "content": ", we can obtain the fused image token " + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "inline_equation", + "content": "z_I^C = R_{\\mathrm{cross}}^M V_G^C" + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "inline_equation", + "content": "V_G^C" + }, + { + "bbox": [ + 47, + 330, + 287, + 390 + ], + "type": "text", + "content": " means the value of the genome feature." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "spans": [ + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "text", + "content": "Reconstruction with relation masking. We feed the input data into two networks shared parameters, where the first network consists of a ViT encoder to yield intact image feature " + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "inline_equation", + "content": "z_{I}" + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "text", + "content": " and a SNN encoder with self-attention blocks to produce genome feature " + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "inline_equation", + "content": "z_{G}" + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "text", + "content": ". Parallely, the second network employs the proposed self- and cross-modality relation masking in first two attention blocks to generate masked features " + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "inline_equation", + "content": "z_{I,M}, z_{G,M}" + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "text", + "content": " for image and genome, respectively. Afterwards, the masked features are incorporated with the intact feature from the other modality and produce amalgamated features " + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "inline_equation", + "content": "z_{I}^{F} = \\text{concat}[z_{I,M}; z_{G}]" + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "inline_equation", + "content": "z_{G}^{F} = \\text{concat}[z_{G,M}; z_{I}]" + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "text", + "content": " for images and genome. The fused features are then put into the decoders " + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "inline_equation", + "content": "h_{I}(\\cdot), h_{G}(\\cdot)" + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "text", + "content": " to reconstruct image and genome " + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "inline_equation", + "content": "\\hat{x}_{I} = h_{I}(z_{I}^{F}), \\hat{x}_{G} = h_{G}(z_{G}^{F})" + }, + { + "bbox": [ + 46, + 391, + 287, + 571 + ], + "type": "text", + "content": ". The overall loss function for the reconstruction of image and genome is:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 64, + 580, + 287, + 596 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 64, + 580, + 287, + 596 + ], + "spans": [ + { + "bbox": [ + 64, + 580, + 287, + 596 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {r e c o n}} = \\left\\| h _ {I} \\left(z _ {I} ^ {F}\\right) - x _ {I} \\right\\| _ {2} ^ {2} + \\left\\| h _ {G} \\left(z _ {G} ^ {F}\\right) - x _ {G} \\right\\| _ {2} ^ {2}. \\tag {7}", + "image_path": "b307d78abaf7f4d481ee68b6c2bfebdd4f2290782268e4d989f774ea92a26b9d.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "content": "The relation masking strategy exploits the token-wise feature relation for mask-and-reconstruct task. It is worth noting that although the strong relation is removed, the intrinsic information within the data is retained [32]. Therefore, with the original complete image and genome as inputs, our relation masking can preserve the intact disease-related semantics. With the relation masking-based reconstruction task, the self-modality relation is encouraged to be recovered by the model to capture disease-related information" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 72, + 545, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 120 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 120 + ], + "type": "text", + "content": "within each modality, and the cross-modality relation is enforced to reconstruct to learn abundant multimodal knowledge to improve the disease-related representation for effective downstream diagnosis tasks transfer." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 127, + 416, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 127, + 416, + 140 + ], + "spans": [ + { + "bbox": [ + 306, + 127, + 416, + 140 + ], + "type": "text", + "content": "3.3. Relation Matching" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 145, + 545, + 217 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 145, + 545, + 217 + ], + "spans": [ + { + "bbox": [ + 305, + 145, + 545, + 217 + ], + "type": "text", + "content": "Considering that the disease-aware relation among diseases is limited in medical data, to provide sufficient semantic relation, we propose relation matching, a global constraint to align the sample-wise relation across self- and cross-modality samples to perform global constraints in the feature space." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "spans": [ + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "type": "text", + "content": "Self-modality matching. Assume one minibatch contains " + }, + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "type": "inline_equation", + "content": "B" + }, + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "type": "text", + "content": " multimodal pairs " + }, + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "type": "inline_equation", + "content": "\\{x_I^i,x_G^i\\}_{i = 1}^B" + }, + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "type": "text", + "content": ", we can obtain the intact feature representations " + }, + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "type": "inline_equation", + "content": "\\{z_I^i,z_G^i\\}_{i = 1}^B" + }, + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "type": "text", + "content": " and masked ones " + }, + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "type": "inline_equation", + "content": "\\{z_{I,M}^{i},z_{G,M}^{i}\\}_{i = 1}^{B}" + }, + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "type": "text", + "content": " via the proposed relation masking strategy. Firstly, we compute the sample-wise relation " + }, + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "type": "inline_equation", + "content": "\\{R_{\\mathrm{II}}^{i,j}\\}_{i,j = 1}^{B},\\{R_{\\mathrm{GG}}^{i,j}\\}_{i,j = 1}^{B}" + }, + { + "bbox": [ + 305, + 217, + 545, + 300 + ], + "type": "text", + "content": " across all intact features of image and genome, respectively:" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 383, + 308, + 545, + 329 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 383, + 308, + 545, + 329 + ], + "spans": [ + { + "bbox": [ + 383, + 308, + 545, + 329 + ], + "type": "interline_equation", + "content": "R _ {\\mathrm {I I}} ^ {i, j} = \\operatorname {s i m} \\left(z _ {I} ^ {i}; z _ {I} ^ {j}\\right) \\tag {8}", + "image_path": "cd86fbe59848a19b4ca00376d75d9f094a02dd135042830e9263aae5bc976676.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 383, + 325, + 468, + 340 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 383, + 325, + 468, + 340 + ], + "spans": [ + { + "bbox": [ + 383, + 325, + 468, + 340 + ], + "type": "interline_equation", + "content": "R _ {\\mathrm {G G}} ^ {i, j} = \\operatorname {s i m} \\left(z _ {G} ^ {i}; z _ {G} ^ {j}\\right),", + "image_path": "89ca56675961190aaffe19b11d691857e9be64a5dcd1cc8e0b0eed96cb179cdc.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 347, + 545, + 383 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 347, + 545, + 383 + ], + "spans": [ + { + "bbox": [ + 305, + 347, + 545, + 383 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 347, + 545, + 383 + ], + "type": "inline_equation", + "content": "\\mathrm{sim}(\\cdot ;\\cdot)" + }, + { + "bbox": [ + 305, + 347, + 545, + 383 + ], + "type": "text", + "content": " denotes the similarity between two features, here we adopt the cosine similarity. Similarly, we acquire the sample relation among masked features:" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 373, + 390, + 545, + 411 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 373, + 390, + 545, + 411 + ], + "spans": [ + { + "bbox": [ + 373, + 390, + 545, + 411 + ], + "type": "interline_equation", + "content": "R _ {\\mathrm {I I}, \\mathrm {M}} ^ {i, j} = \\operatorname {s i m} \\left(z _ {I, M} ^ {i}; z _ {I, M} ^ {j}\\right), \\tag {9}", + "image_path": "5d61940f07aadcd07604c816691dbeb34f1d21e7d7bc48556acdc6f54bc243a1.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 369, + 408, + 483, + 423 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 369, + 408, + 483, + 423 + ], + "spans": [ + { + "bbox": [ + 369, + 408, + 483, + 423 + ], + "type": "interline_equation", + "content": "R _ {\\mathrm {G G}, \\mathrm {M}} ^ {i, j} = \\operatorname {s i m} (z _ {G, M} ^ {i}; z _ {G, M} ^ {j}).", + "image_path": "1761b440420064e91820532f5df68a92d607efa5b8952a32362c566b9d4103cd.jpg" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 305, + 430, + 545, + 466 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 430, + 545, + 466 + ], + "spans": [ + { + "bbox": [ + 305, + 430, + 545, + 466 + ], + "type": "text", + "content": "We aim to ensure the relation consistency between intact and masked features. The matching objective for self-modality feature relation can be formulated as:" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 473, + 545, + 517 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 473, + 545, + 517 + ], + "spans": [ + { + "bbox": [ + 306, + 473, + 545, + 517 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {s e l f}} = \\frac {1}{2 B ^ {2}} \\sum_ {i = 1} ^ {B} \\sum_ {j = 1} ^ {B} \\left| \\left| R _ {\\mathrm {I I}} ^ {i, j} - R _ {\\mathrm {I I}, \\mathrm {M}} ^ {i, j} \\right| \\right| _ {2} ^ {2} + \\left| \\left| R _ {\\mathrm {G G}} ^ {i, j} - R _ {\\mathrm {G G}, \\mathrm {M}} ^ {i, j} \\right| \\right| _ {2} ^ {2}. \\tag {10}", + "image_path": "24e1d1af35ba4d224763155edf0bc5a2bd088e108cad915aaa72cac0ac4b4aae.jpg" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 305, + 517, + 545, + 554 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 517, + 545, + 554 + ], + "spans": [ + { + "bbox": [ + 305, + 517, + 545, + 554 + ], + "type": "text", + "content": "Cross-modality matching. Furthermore, to incorporate multimodal information and bridge the gap of different modalities, we compute the cross-modality relation:" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 376, + 560, + 545, + 582 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 376, + 560, + 545, + 582 + ], + "spans": [ + { + "bbox": [ + 376, + 560, + 545, + 582 + ], + "type": "interline_equation", + "content": "R _ {\\mathrm {I G}} ^ {i, j} = \\operatorname {s i m} \\left(z _ {I} ^ {i}; z _ {G} ^ {j}\\right), \\tag {11}", + "image_path": "161ca30696a76227813f68e9fae507605cadaa25bb2348bf59a7d54870d6f2c0.jpg" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 372, + 578, + 481, + 594 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 372, + 578, + 481, + 594 + ], + "spans": [ + { + "bbox": [ + 372, + 578, + 481, + 594 + ], + "type": "interline_equation", + "content": "R _ {\\mathrm {I G , M}} ^ {i, j} = \\mathrm {s i m} (z _ {I, M} ^ {i}; z _ {G, M} ^ {j}),", + "image_path": "a78c4ca2d569cd42085c48a42a7a98789340e272bb27bcc0e4a12ace563ddcce.jpg" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 305, + 601, + 545, + 675 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 601, + 545, + 675 + ], + "spans": [ + { + "bbox": [ + 305, + 601, + 545, + 675 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 601, + 545, + 675 + ], + "type": "inline_equation", + "content": "\\{R_{\\mathrm{IG}}^{i,j}\\}_{i,j = 1}^{B}" + }, + { + "bbox": [ + 305, + 601, + 545, + 675 + ], + "type": "text", + "content": " represents the cross-modality relation across intact multimodal features, and " + }, + { + "bbox": [ + 305, + 601, + 545, + 675 + ], + "type": "inline_equation", + "content": "\\{R_{\\mathrm{IG,M}}^{i,j}\\}_{i,j = 1}^{B}" + }, + { + "bbox": [ + 305, + 601, + 545, + 675 + ], + "type": "text", + "content": " means the relation across masked ones. We intend to ensure the cross-modality relation to be invariant between masked and intact features. The cross-modality feature relation can be calculated as:" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 347, + 681, + 545, + 715 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 347, + 681, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 347, + 681, + 545, + 715 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {c r o s s}} = \\frac {1}{B ^ {2}} \\sum_ {i = 1} ^ {B} \\sum_ {j = 1} ^ {B} \\left| \\left| R _ {\\mathrm {I G}} ^ {i, j} - R _ {\\mathrm {I G}, \\mathrm {M}} ^ {i, j} \\right| \\right| _ {2} ^ {2}. \\tag {12}", + "image_path": "0906b170a81cd70b2861d4e416d5d7ad04ad74b7b9a70902426fefaac72954f1.jpg" + } + ] + } + ], + "index": 23 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "21456" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 52, + 80, + 542, + 222 + ], + "blocks": [ + { + "bbox": [ + 47, + 69, + 544, + 80 + ], + "lines": [ + { + "bbox": [ + 47, + 69, + 544, + 80 + ], + "spans": [ + { + "bbox": [ + 47, + 69, + 544, + 80 + ], + "type": "text", + "content": "Table 1. Comparison with state-of-the-art pre-training algorithms via fine-tuning evaluation on four downstream retinal image-based tasks." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 52, + 80, + 542, + 222 + ], + "lines": [ + { + "bbox": [ + 52, + 80, + 542, + 222 + ], + "spans": [ + { + "bbox": [ + 52, + 80, + 542, + 222 + ], + "type": "table", + "html": "
MethodMasking LevelAPTOSRFMiDPALMCRP
InputRelationQwKappa ↑ROC-AUC ↑Dice-Score ↑MSE ↓ROC-AUC ↑
Training from scratch (baseline)--83.2592.9179.443.40558.05
Contrastive-based Pre-training Methods
SimCLR [8]--84.5093.7573.183.42663.92
MoCo v3 [17]--85.0394.0275.733.42165.33
ContIG [34]--86.2794.5980.253.18473.57
MIM-based Pre-Training Methods
MAE [16]✓✗84.0692.7174.283.48864.29
SimMIM [43]✓✗84.6793.8072.733.45066.08
MultiMAE [3]✓✗85.5994.2675.923.41167.51
M3AE [13]✓✗86.8594.7277.353.39468.39
mc-BEiT [25]✓✗87.1594.3777.403.37266.38
AttMask [19]✓✗87.7394.9178.593.26269.40
MRM✗✓89.8396.3181.453.10775.90
", + "image_path": "ea6ac4b1650523cb0b54879127f4e73ebf0341756be6c44e4efb67002ea48ea5.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 241, + 287, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 241, + 287, + 266 + ], + "spans": [ + { + "bbox": [ + 47, + 241, + 287, + 266 + ], + "type": "text", + "content": "With the self- and cross-modality feature relation, we can formulate the overall relation matching objective as:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 119, + 271, + 287, + 283 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 119, + 271, + 287, + 283 + ], + "spans": [ + { + "bbox": [ + 119, + 271, + 287, + 283 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {m a t c h}} = \\mathcal {L} _ {\\text {s e l f}} + \\mathcal {L} _ {\\text {c r o s s}}. \\tag {13}", + "image_path": "9c474a0c8d3369027a3776037a879a4f69b7692d2331b8b42a95d2ac8c064de4.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 289, + 287, + 337 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 289, + 287, + 337 + ], + "spans": [ + { + "bbox": [ + 47, + 289, + 287, + 337 + ], + "type": "text", + "content": "The relation matching encourages global constraints in the feature space to provide sufficient semantic relation, which enjoys the complementary advantages of pixel-wise data reconstruction loss in Eq. (7)." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 342, + 238, + 355 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 342, + 238, + 355 + ], + "spans": [ + { + "bbox": [ + 47, + 342, + 238, + 355 + ], + "type": "text", + "content": "3.4. Pre-training and Transfer Inference" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 361, + 287, + 432 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 361, + 287, + 432 + ], + "spans": [ + { + "bbox": [ + 46, + 361, + 287, + 432 + ], + "type": "text", + "content": "In the pre-training phase, the image and genome as multimodal inputs are fed into the model. We adopt the proposed relation masking to generate masked features, and employ the relation matching as the global constraint with the data reconstruction loss to jointly optimize the overall framework:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 111, + 438, + 287, + 451 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 438, + 287, + 451 + ], + "spans": [ + { + "bbox": [ + 111, + 438, + 287, + 451 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {o v e r a l l}} = \\mathcal {L} _ {\\text {r e c o n}} + \\lambda \\mathcal {L} _ {\\text {m a t c h}}, \\tag {14}", + "image_path": "546181f71ef60370758b58dcb8f3c65e68e3e5ffa19b16b4fe0e39336b59935c.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 456, + 287, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 456, + 287, + 552 + ], + "spans": [ + { + "bbox": [ + 46, + 456, + 287, + 552 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 456, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 456, + 287, + 552 + ], + "type": "text", + "content": " denotes the balanced coefficient to control contributions of the reconstruction task and the relation matching. During the phase of downstream image-based fine-tuning, we discard the genome branch and utilize the image encoder to extract the feature representation without relation masking. The pre-trained encoder following a randomly initial task-relevant head is fine-tuned on downstream tasks for evaluation." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 562, + 127, + 574 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 562, + 127, + 574 + ], + "spans": [ + { + "bbox": [ + 47, + 562, + 127, + 574 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 582, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 287, + 713 + ], + "type": "text", + "content": "We pre-train MRM on two multimodal datasets involving retinal images with genetics, and pathology images with genetics, respectively. To evaluate the quality of the representations learned on retinal images, we transfer the pre-trained model to four downstream retinal image-based tasks. As for the model pre-trained on pathology images, we assess it on a downstream pathology image-based task. The gene-image association analysis is performed to study the relation between images and genetics towards disease diagnosis. Finally, we extend our method to image pre-training to verify the effectiveness on single modality." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 241, + 422, + 254 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 241, + 422, + 254 + ], + "spans": [ + { + "bbox": [ + 306, + 241, + 422, + 254 + ], + "type": "text", + "content": "4.1. Experimental Setup" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 260, + 463, + 272 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 260, + 463, + 272 + ], + "spans": [ + { + "bbox": [ + 306, + 260, + 463, + 272 + ], + "type": "text", + "content": "4.1.1 Retinal Images with Genetics" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 279, + 545, + 363 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 279, + 545, + 363 + ], + "spans": [ + { + "bbox": [ + 304, + 279, + 545, + 363 + ], + "type": "text", + "content": "Pre-training. We use UKB [33] to conduct the self-supervised pre-training, which is one of the largest multimodal images and genetics datasets. Following the previous work ContIG [34], we leverage the retinal fundus dataset as the pre-training set, which contains 155,238 images, and the genetics including 155,238 Raw-SNP samples, 145,206 PGS samples and 93,216 burden scores." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 364, + 545, + 388 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 364, + 545, + 388 + ], + "spans": [ + { + "bbox": [ + 305, + 364, + 545, + 388 + ], + "type": "text", + "content": "Downstream Transfer. We introduce four tasks to evaluate and compare the effectiveness of the model pre-training." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 388, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 19, + "blocks": [ + { + "bbox": [ + 304, + 388, + 545, + 496 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 388, + 545, + 496 + ], + "spans": [ + { + "bbox": [ + 304, + 388, + 545, + 496 + ], + "type": "text", + "content": "1) Diabetic Retinopathy Detection (APTOS). The APTOS [1] is a fundus disease dataset including 35,126 2D images across five categories. All images are resized as " + }, + { + "bbox": [ + 304, + 388, + 545, + 496 + ], + "type": "inline_equation", + "content": "224 \\times 224" + }, + { + "bbox": [ + 304, + 388, + 545, + 496 + ], + "type": "text", + "content": " for efficient fine-tuning. We split " + }, + { + "bbox": [ + 304, + 388, + 545, + 496 + ], + "type": "inline_equation", + "content": "80\\%" + }, + { + "bbox": [ + 304, + 388, + 545, + 496 + ], + "type": "text", + "content": " as the training set to fine-tune the pre-trained MRM model, and the remaining " + }, + { + "bbox": [ + 304, + 388, + 545, + 496 + ], + "type": "inline_equation", + "content": "20\\%" + }, + { + "bbox": [ + 304, + 388, + 545, + 496 + ], + "type": "text", + "content": " as the test set is used to evaluate the performance. The Quadratic Weighted Kappa (QwKappa) [14] is adopted as the metric to measure the agreement between the prediction and ground truth." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 497, + 545, + 591 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 497, + 545, + 591 + ], + "spans": [ + { + "bbox": [ + 304, + 497, + 545, + 591 + ], + "type": "text", + "content": "2) Retinal Fundus Disease Classification (RFMiD). The Retinal Fundus Multi-disease Image Dataset (RFMiD) [29] consists of 3200 annotated retinal fundus images of 46 eye diseases. RFMiD formulates a multi-label classification task since the images may contain multiple conditions. We split " + }, + { + "bbox": [ + 304, + 497, + 545, + 591 + ], + "type": "inline_equation", + "content": "80\\%" + }, + { + "bbox": [ + 304, + 497, + 545, + 591 + ], + "type": "text", + "content": " as the training set and " + }, + { + "bbox": [ + 304, + 497, + 545, + 591 + ], + "type": "inline_equation", + "content": "20\\%" + }, + { + "bbox": [ + 304, + 497, + 545, + 591 + ], + "type": "text", + "content": " as the test set. The area under the ROC curve (ROC-AUC) is used as the metric to evaluate the classification results." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 593, + 545, + 652 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 593, + 545, + 652 + ], + "spans": [ + { + "bbox": [ + 304, + 593, + 545, + 652 + ], + "type": "text", + "content": "3) Pathological Myopia Segmentation (PALM). The PALM dataset [18] contains 1200 images with disc and atrophy segmentation annotations. We use 800 images as the training split and 400 images as test split. The dice score is adopted as the segmentation evaluation metric." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "4) Cardiovascular Risk Prediction (CRP). The retinal fundus images of UKB dataset can also be utilized to CRP including age, sex, smoking status, systolic and diastolic blood pressure (SBP, DBP), and body mass index (BMI) [31], formulating a regression with classification" + } + ] + } + ], + "index": 18 + } + ], + "sub_type": "text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "21457" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 61, + 81, + 274, + 200 + ], + "blocks": [ + { + "bbox": [ + 47, + 69, + 284, + 80 + ], + "lines": [ + { + "bbox": [ + 47, + 69, + 284, + 80 + ], + "spans": [ + { + "bbox": [ + 47, + 69, + 284, + 80 + ], + "type": "text", + "content": "Table 2. Transfer results on downstream pathological image task." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 61, + 81, + 274, + 200 + ], + "lines": [ + { + "bbox": [ + 61, + 81, + 274, + 200 + ], + "spans": [ + { + "bbox": [ + 61, + 81, + 274, + 200 + ], + "type": "table", + "html": "
MethodGG
Acc ↑ROC-AUC ↑
Training from scratch (baseline)73.8390.16
Contrastive-based Pre-training
SimCLR [9]74.2490.62
MoCo v3 [11]74.7890.90
ContIG [34]75.1491.25
MIM-based Pre-Training
MAE [16]73.7590.44
SimMIM [43]73.9690.80
MultiMAE [3]74.4591.03
mc-BEI T [25]74.8291.35
AttMask [19]75.3691.75
MRM76.1792.07
", + "image_path": "90866f42c3601d428b777a63c2b39498faedb168a7fb7a88a36cf92a44c08af7.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 220, + 288, + 258 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 220, + 288, + 258 + ], + "spans": [ + { + "bbox": [ + 46, + 220, + 288, + 258 + ], + "type": "text", + "content": "task. We use mean squared error (MSE) as the metric for numerical factors, i.e., age, BMI, SBP, DBP, and the ROC-AUC for the categorical factors, i.e., sex and smoking status." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 271, + 217, + 283 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 271, + 217, + 283 + ], + "spans": [ + { + "bbox": [ + 47, + 271, + 217, + 283 + ], + "type": "text", + "content": "4.1.2 Pathology Images with Genetics" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 289, + 287, + 373 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 289, + 287, + 373 + ], + "spans": [ + { + "bbox": [ + 46, + 289, + 287, + 373 + ], + "type": "text", + "content": "Pre-training. We use TCGA-GBM with TCGA-LGG dataset [37] to conduct the pre-training, which consists of 736 paired samples of pathology slides and genetic profiles. We resize the curated pathology slides with the shape of " + }, + { + "bbox": [ + 46, + 289, + 287, + 373 + ], + "type": "inline_equation", + "content": "224 \\times 224" + }, + { + "bbox": [ + 46, + 289, + 287, + 373 + ], + "type": "text", + "content": " as inputs. Considering each patient has multiple curated slides, we select one of them associated with one genetic profile as an input pair." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 374, + 287, + 469 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 374, + 287, + 469 + ], + "spans": [ + { + "bbox": [ + 46, + 374, + 287, + 469 + ], + "type": "text", + "content": "Downstream Transfer. We leverage glioma grading (GG) to evaluate performance. The GG can improve the treatment planning for accurate determination. The TCGA dataset contains WHO grading labels including grade II, III and IV. We fine-tune the pre-trained model on training set with " + }, + { + "bbox": [ + 46, + 374, + 287, + 469 + ], + "type": "inline_equation", + "content": "80\\%" + }, + { + "bbox": [ + 46, + 374, + 287, + 469 + ], + "type": "text", + "content": " data split and evaluate the performance on " + }, + { + "bbox": [ + 46, + 374, + 287, + 469 + ], + "type": "inline_equation", + "content": "20\\%" + }, + { + "bbox": [ + 46, + 374, + 287, + 469 + ], + "type": "text", + "content": " data split. The accuracy and ROC-AUC are employed as the metrics to measure the classification results." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 477, + 180, + 490 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 477, + 180, + 490 + ], + "spans": [ + { + "bbox": [ + 47, + 477, + 180, + 490 + ], + "type": "text", + "content": "4.2. Implementation Details" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "spans": [ + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "type": "text", + "content": "Following prior works [16, 44], we adopt ViT-base as the image encoder and SNN network as the genome encoder to learn representations. The ViT and SNN models are trained via AdamW [26] and Adam [21], respectively, both with an initial learning rate of " + }, + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "type": "inline_equation", + "content": "1 \\times 10^{-3}" + }, + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "type": "text", + "content": ". We use PyTorch [30] to implement our models, and train all models for 50 epochs with the batch size of 256 for UKB and 8 for TCGA. In relation matching, for efficiency, we randomly select 8 pair of multimodal features to perform matching constraint for two datasets. All comparisons [8, 11, 34, 16, 43, 3, 13, 25, 19] share the same settings to achieve a fair comparison. The balanced coefficient " + }, + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "type": "text", + "content": " in Eq. (14) is set as 1.0, and the masking ratios " + }, + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "type": "inline_equation", + "content": "\\tau_{I}, \\tau_{G}" + }, + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "type": "text", + "content": " for images and genetics are equal to " + }, + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 46, + 495, + 287, + 664 + ], + "type": "text", + "content": ", respectively." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 671, + 231, + 684 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 671, + 231, + 684 + ], + "spans": [ + { + "bbox": [ + 47, + 671, + 231, + 684 + ], + "type": "text", + "content": "4.3. Comparison with State-of-the-arts" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 689, + 287, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 287, + 712 + ], + "type": "text", + "content": "In this section, to assess the quality of feature representations to various downstream tasks, we fine-tune the encoder" + } + ] + } + ], + "index": 9 + }, + { + "type": "table", + "bbox": [ + 307, + 91, + 545, + 185 + ], + "blocks": [ + { + "bbox": [ + 305, + 69, + 545, + 90 + ], + "lines": [ + { + "bbox": [ + 305, + 69, + 545, + 90 + ], + "spans": [ + { + "bbox": [ + 305, + 69, + 545, + 90 + ], + "type": "text", + "content": "Table 3. Ablation study of each proposed component in relation masking and relation matching on retinal image-based tasks." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 307, + 91, + 545, + 185 + ], + "lines": [ + { + "bbox": [ + 307, + 91, + 545, + 185 + ], + "spans": [ + { + "bbox": [ + 307, + 91, + 545, + 185 + ], + "type": "table", + "html": "
MaskingMatchingAPTOSRFMiDPALMCRP
RM selfRM crossL selfL crossQwKappaROC-AUC↑ Dice-Score↑ MSE↓ ROC-AUC ↑
83.6590.4972.513.49661.57
✓86.3793.4875.293.35267.21
✓85.1092.7174.203.41864.82
✓✓87.5094.2877.233.28370.52
✓✓✓88.2794.9478.493.21673.73
✓✓✓88.6595.5179.773.16274.27
✓✓✓✓89.8396.3181.453.10775.90
", + "image_path": "d16cf3e3ef8fa718a0823e32ebf9d016b8a523ed41f53a1e0e62b8b302c99388.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 205, + 545, + 229 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 205, + 545, + 229 + ], + "spans": [ + { + "bbox": [ + 304, + 205, + 545, + 229 + ], + "type": "text", + "content": "with an initial task-relevant head together on the training set, and evaluate the downstream tasks on the test set." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "spans": [ + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "text", + "content": "Retinal Images with Genetics. We compare MRM pretrained on UKB with state-of-the-art methods [8, 11, 34, 16, 43, 3, 13, 25, 19] on four downstream retinal image-based tasks in Table 1. MRM achieves " + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "inline_equation", + "content": "89.83\\%" + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "inline_equation", + "content": "96.31\\%" + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "inline_equation", + "content": "81.45\\%" + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "inline_equation", + "content": "3.107" + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "inline_equation", + "content": "75.90\\%" + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "text", + "content": " scores on APTOS, RFMiD, PALM and CRP tasks, respectively, outperforming other comparisons by a clear margin in all tasks including disease classification, segmentation and regression. Particularly, compared with MIM-based pre-training methods, MRM is superior over the second best one AttMask [19] with " + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "inline_equation", + "content": "2.10\\%" + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "inline_equation", + "content": "1.40\\%" + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "inline_equation", + "content": "2.86\\%" + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "inline_equation", + "content": "0.155" + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "inline_equation", + "content": "6.50\\%" + }, + { + "bbox": [ + 304, + 230, + 546, + 409 + ], + "type": "text", + "content": " scores on four tasks. These results reflect that masking out relation and retaining intact information within the input can obtain better feature representation than MIM-based input masking and per-sample reconstruction strategies for medical data." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 410, + 545, + 530 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 410, + 545, + 530 + ], + "spans": [ + { + "bbox": [ + 304, + 410, + 545, + 530 + ], + "type": "text", + "content": "Pathology Images with Genetics. To verify the versatility of the proposed framework, we pre-train MRM on pathology image-genome dataset TCGA and fine-tune the model on downstream grade grading task to evaluate the transfer results. From Table 2, compared with other pretraining methods, MRM yields state-of-the-art performance with " + }, + { + "bbox": [ + 304, + 410, + 545, + 530 + ], + "type": "inline_equation", + "content": "76.17\\%" + }, + { + "bbox": [ + 304, + 410, + 545, + 530 + ], + "type": "text", + "content": " accuracy and " + }, + { + "bbox": [ + 304, + 410, + 545, + 530 + ], + "type": "inline_equation", + "content": "92.07\\%" + }, + { + "bbox": [ + 304, + 410, + 545, + 530 + ], + "type": "text", + "content": " ROC-AUC scores, indicating its effectiveness and flexibility on various types of medical images. Hence, the proposed MRM is able to achieve significantly better self-supervised leaning." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 538, + 400, + 551 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 538, + 400, + 551 + ], + "spans": [ + { + "bbox": [ + 306, + 538, + 400, + 551 + ], + "type": "text", + "content": "4.4. Ablation Study" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 557, + 545, + 581 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 557, + 545, + 581 + ], + "spans": [ + { + "bbox": [ + 304, + 557, + 545, + 581 + ], + "type": "text", + "content": "We ablate the effectiveness of each component in MRM on retinal image dataset." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": "Effectiveness of relation masking. We study the effectiveness of the proposed self- and cross-modality relation masking. We start from a baseline that trains the autoencoder to construct the multimodal data, we first mask out a portion of self-modality relation in both image and genome branches. From Table 3, the self-modality relation masking brings performance gains by " + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "inline_equation", + "content": "2.72\\%" + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "inline_equation", + "content": "2.99\\%" + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "inline_equation", + "content": "2.78\\%" + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": ", 0.144 and " + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "inline_equation", + "content": "5.64\\%" + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": " scores on APTOS, RFMiD, PALM and CRP tasks, respectively. Then, we further mask out the cross-modality relation, the results show consistent increases by " + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "inline_equation", + "content": "1.13\\%" + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "inline_equation", + "content": "0.80\\%" + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "inline_equation", + "content": "1.94\\%" + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": ", 0.069 and " + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "inline_equation", + "content": "3.31\\%" + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": " on four tasks. To" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "text", + "content": "21458" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 66, + 73, + 282, + 229 + ], + "blocks": [ + { + "bbox": [ + 66, + 73, + 282, + 229 + ], + "lines": [ + { + "bbox": [ + 66, + 73, + 282, + 229 + ], + "spans": [ + { + "bbox": [ + 66, + 73, + 282, + 229 + ], + "type": "image", + "image_path": "c2600edaefb30c5cc0d50ca9aa1b2a6a193202d993f1c363225df85f7836040f.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 237, + 287, + 292 + ], + "lines": [ + { + "bbox": [ + 46, + 237, + 287, + 292 + ], + "spans": [ + { + "bbox": [ + 46, + 237, + 287, + 292 + ], + "type": "text", + "content": "Figure 3. Comparison of reconstruction results of different methods. From left to right suggests the original input and the reconstructed images by MAE [16], AttMask [19] and our MRM. We can observe that MRM can preserve the disease regions framed in blue while MIM-based methods lose them." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 315, + 286, + 410 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 315, + 286, + 410 + ], + "spans": [ + { + "bbox": [ + 46, + 315, + 286, + 410 + ], + "type": "text", + "content": "qualitatively verify the impact of the relation masking, we visualize the reconstruction images of different methods. Figure 3 illustrates that MIM-based approaches [16, 19] lose the tiny disease regions, while MRM can reconstruct almost complete disease regions. These advantages indicate that our relation masking in self- and cross-modality levels can preserve the disease semantics thereby improving the quality of the feature representation." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "spans": [ + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "text", + "content": "Impact of relation matching. To observe the impact of the self- and cross-modality relation matching, on the top of the model with relation masking, we employ the self-modality matching constraint. As implied in Table 3, self-modality matching leads to the transfer result improvements by " + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "inline_equation", + "content": "0.77\\%" + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "inline_equation", + "content": "0.66\\%" + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "inline_equation", + "content": "1.26\\%" + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "inline_equation", + "content": "0.067" + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "inline_equation", + "content": "3.21\\%" + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "text", + "content": " scores on APTOS, RFMiD, PALM and CRP tasks, respectively. When adding the cross-modality relation matching, the performance continuously grows by " + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "inline_equation", + "content": "1.56\\%" + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "inline_equation", + "content": "1.37\\%" + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "inline_equation", + "content": "2.96\\%" + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "inline_equation", + "content": "0.109" + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "inline_equation", + "content": "2.17\\%" + }, + { + "bbox": [ + 46, + 412, + 286, + 579 + ], + "type": "text", + "content": " scores on four downstream tasks. The results illustrate that both self- and cross-modality relation matching can boost the representation learning, and they can render complementary constraints to achieve sample relation invariant when masking the feature relation." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": "Masking ratios. To understand the influence of masking ratios " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "\\tau_{I}" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "\\tau_{G}" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": " for images and genetics, we fine-tune the pre-trained model on diabetic retinopathy detection task under different masking ratios. Firstly, we mask the self- and cross-modality relation for image features with different ratio " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "\\tau_{I}" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": " including " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "25\\%" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "90\\%" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": ". From Figure 4 (a), the best choice for " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "\\tau_{I}" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": " is " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": ", and the performance decreases when diminishing or enlarging the ratio. As the ratio reduces from " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": ", the transfer result drops remarkably by " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "1.35\\%" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": ". Moreover, we analyze the effect of masking ratio " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "\\tau_{G}" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": " for genetics and find that " + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": " is good for" + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 309, + 72, + 425, + 150 + ], + "blocks": [ + { + "bbox": [ + 309, + 72, + 425, + 150 + ], + "lines": [ + { + "bbox": [ + 309, + 72, + 425, + 150 + ], + "spans": [ + { + "bbox": [ + 309, + 72, + 425, + 150 + ], + "type": "image", + "image_path": "74264b881bb2b0105b2c71aacb91d2023bd90bab1df5734caef50fc2a3362c77.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 369, + 151, + 377, + 158 + ], + "lines": [ + { + "bbox": [ + 369, + 151, + 377, + 158 + ], + "spans": [ + { + "bbox": [ + 369, + 151, + 377, + 158 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 432, + 72, + 542, + 150 + ], + "blocks": [ + { + "bbox": [ + 432, + 72, + 542, + 150 + ], + "lines": [ + { + "bbox": [ + 432, + 72, + 542, + 150 + ], + "spans": [ + { + "bbox": [ + 432, + 72, + 542, + 150 + ], + "type": "image", + "image_path": "5ee7566523083381042acc921d1265e0b945a30d9f01a514cd68739cc522d6da.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 488, + 152, + 495, + 158 + ], + "lines": [ + { + "bbox": [ + 488, + 152, + 495, + 158 + ], + "spans": [ + { + "bbox": [ + 488, + 152, + 495, + 158 + ], + "type": "text", + "content": "(b)" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 306, + 162, + 545, + 184 + ], + "lines": [ + { + "bbox": [ + 306, + 162, + 545, + 184 + ], + "spans": [ + { + "bbox": [ + 306, + 162, + 545, + 184 + ], + "type": "text", + "content": "Figure 4. Ablation study. (a) Masking ratios " + }, + { + "bbox": [ + 306, + 162, + 545, + 184 + ], + "type": "inline_equation", + "content": "\\tau_{I}" + }, + { + "bbox": [ + 306, + 162, + 545, + 184 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 162, + 545, + 184 + ], + "type": "inline_equation", + "content": "\\tau_{G}" + }, + { + "bbox": [ + 306, + 162, + 545, + 184 + ], + "type": "text", + "content": " for image and genome. (b) Balanced coefficient " + }, + { + "bbox": [ + 306, + 162, + 545, + 184 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 306, + 162, + 545, + 184 + ], + "type": "text", + "content": " of two loss functions." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 331, + 205, + 522, + 300 + ], + "blocks": [ + { + "bbox": [ + 331, + 194, + 520, + 205 + ], + "lines": [ + { + "bbox": [ + 331, + 194, + 520, + 205 + ], + "spans": [ + { + "bbox": [ + 331, + 194, + 520, + 205 + ], + "type": "text", + "content": "Table 4. Results of gene-image association analysis." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 331, + 205, + 522, + 300 + ], + "lines": [ + { + "bbox": [ + 331, + 205, + 522, + 300 + ], + "spans": [ + { + "bbox": [ + 331, + 205, + 522, + 300 + ], + "type": "table", + "html": "
MethodFound Regions ↑
Training from scratch4
SimCLR [9]5
MoCo v3 [11]6
ContIG [34]10
MAE [16]8
SimMIM [43]10
MultiMAE [3]13
mc-BEI T [25]14
AttMask [19]16
MRM18
", + "image_path": "530756ddeb49d3fb3826a1bbd32e1f43d0ec0dbaa41dc09b4338aab44f82b1bc.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 322, + 481, + 333 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 322, + 481, + 333 + ], + "spans": [ + { + "bbox": [ + 306, + 322, + 481, + 333 + ], + "type": "text", + "content": "representation learning and transfer results." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "spans": [ + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "text", + "content": "Loss balanced coefficient " + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "text", + "content": ". We study the sensitivity of MRM towards the balanced coefficients " + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "text", + "content": " for controlling two loss functions " + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{recon}}" + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{match}}" + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "text", + "content": " in Eq. (14), as shown in Figure 4 (b). It can be observed that the performance rises with the balanced coefficients " + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "text", + "content": " increasing from 0.1 to 1.0, while it plunges when " + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "text", + "content": " is larger than 1.0. These suggest that the proposed relation matching leads to beneficial representation learning with the appropriate range of " + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 334, + 545, + 453 + ], + "type": "text", + "content": ", either too strong or too weak of the relation matching constraint damage the quality of the feature representation." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 463, + 483, + 475 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 463, + 483, + 475 + ], + "spans": [ + { + "bbox": [ + 306, + 463, + 483, + 475 + ], + "type": "text", + "content": "4.5. Gene-image Association Analysis" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 482, + 545, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 482, + 545, + 613 + ], + "spans": [ + { + "bbox": [ + 304, + 482, + 545, + 613 + ], + "type": "text", + "content": "To obtain an interpretable understanding on how genetics can improve images representation learning, we conduct gene-image association analysis for all models. This association analysis is a statistical tool for finding individual genetic regions correlated with image features according to the disease traits. The better the image representation, the more associated regions are expected to be discovered. Table 4 shows the number of independent regions each model finds, where we observe that MRM finds the most disease-related regions from genetics, explaining why genetics can improve image representation learning in our model." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 622, + 524, + 635 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 622, + 524, + 635 + ], + "spans": [ + { + "bbox": [ + 306, + 622, + 524, + 635 + ], + "type": "text", + "content": "4.6. Extension to Single Modality Pre-training" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 641, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 545, + 713 + ], + "type": "text", + "content": "To study the application of the proposed MRM on single modality, we pre-train MRM using merely image modality on retinal dataset from UKB, and evaluate the feature representation on downstream tasks. Specifically, during the pre-training phase, we remove the cross-modality attention layers and adopt self-attention with self-modality relation" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "21459" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 91, + 288, + 201 + ], + "blocks": [ + { + "bbox": [ + 47, + 69, + 287, + 90 + ], + "lines": [ + { + "bbox": [ + 47, + 69, + 287, + 90 + ], + "spans": [ + { + "bbox": [ + 47, + 69, + 287, + 90 + ], + "type": "text", + "content": "Table 5. Transfer results with single image modality pre-training on retinal image-based tasks." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 91, + 288, + 201 + ], + "lines": [ + { + "bbox": [ + 48, + 91, + 288, + 201 + ], + "spans": [ + { + "bbox": [ + 48, + 91, + 288, + 201 + ], + "type": "table", + "html": "
MethodAPTOSRFMiDPALMCRP
QwKappa ↑ROC-AUC ↑Dice-Score ↑MSE ↓ROC-AUC ↑
Training from scratch79.2689.2777.583.44653.56
SimCLR [8]81.4390.5172.523.45359.25
MoCo v3 [17]82.2091.8273.973.43761.73
ContIG [34]82.8991.5579.173.30667.40
MAE [16]78.3188.6273.053.50360.32
SimMIM [43]79.9189.4771.393.46861.09
MultiMAE [3]80.5590.9174.523.42762.14
mc-BEI T [25]82.5991.7875.843.38863.61
AttMask [19]83.8092.3676.503.28564.77
MRM85.4693.1180.263.24570.15
", + "image_path": "155718fbf34ee7ecd61f934f28928e73fbb4a77ab30fddc6bc696a78e05f7af4.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 220, + 287, + 304 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 220, + 287, + 304 + ], + "spans": [ + { + "bbox": [ + 46, + 220, + 287, + 304 + ], + "type": "text", + "content": "masking to capture the representation. The image feature is directly fed into the image decoder to reconstruct the image without multimodal fusion. As for the relation matching, only self-modality matching is employed for image features. Table 5 indicates that MRM exhibits the best transfer ability across four downstream tasks, verifying the effectiveness of MRM with single image modality pre-training." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 313, + 230, + 327 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 313, + 230, + 327 + ], + "spans": [ + { + "bbox": [ + 47, + 313, + 230, + 327 + ], + "type": "text", + "content": "5. Broader Impact and Limitations" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 333, + 288, + 513 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 333, + 288, + 513 + ], + "spans": [ + { + "bbox": [ + 46, + 333, + 288, + 513 + ], + "type": "text", + "content": "The proposed MRM framework, consisting of relation masking and relation matching, can enable the model to capture relation information by token-wise feature masking and sample-wise global relation constraint, thereby learning better feature representation. Extensive experiments across various downstream diagnosis tasks demonstrate that the MRM has superior transfer ability over state-of-the-art methods, and it can also applies single image modality pretraining to achieve compelling performance. Moreover, in this work, we assume the data distribution between downstream datasets and the pre-training dataset is identical, and do not consider the issue of data domain shift. Hence, in future work, we will improve our framework towards data domain shift issue between pre-training dataset and various downstream datasets." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 522, + 119, + 534 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 522, + 119, + 534 + ], + "spans": [ + { + "bbox": [ + 47, + 522, + 119, + 534 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 542, + 287, + 662 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 542, + 287, + 662 + ], + "spans": [ + { + "bbox": [ + 46, + 542, + 287, + 662 + ], + "type": "text", + "content": "In this work, we present MRM framework to jointly leverage medical images and genetics for self-supervised pre-training. Instead of explicitly masking inputs, we design the relation masking to mask out feature relation and enable the model to capture informative patterns, which can retain intact disease-related semantics. Moreover, to enrich semantic relation, we present relation matching by exploiting inter-sample relation to encourage global constraints in the feature space. Extensive experiments verify the effectiveness of MRM on various downstream diagnosis tasks." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 671, + 106, + 684 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 671, + 106, + 684 + ], + "spans": [ + { + "bbox": [ + 48, + 671, + 106, + 684 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 52, + 691, + 286, + 712 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 52, + 691, + 286, + 702 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 691, + 286, + 702 + ], + "spans": [ + { + "bbox": [ + 52, + 691, + 286, + 702 + ], + "type": "text", + "content": "[1] Aptos 2019 blindness detection." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 68, + 703, + 205, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 703, + 205, + 712 + ], + "spans": [ + { + "bbox": [ + 68, + 703, + 205, + 712 + ], + "type": "text", + "content": "https://www.kaggle.com/c/" + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 712 + ], + "type": "list", + "angle": 0, + "index": 25, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 94 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 94 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 94 + ], + "type": "text", + "content": "aptos2019-blindnessdetection/ Accessed: 2021-11-04.6" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 311, + 95, + 547, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 95, + 547, + 149 + ], + "spans": [ + { + "bbox": [ + 311, + 95, + 547, + 149 + ], + "type": "text", + "content": "[2] Shekoofeh Azizi, Basil Mustafa, Fiona Ryan, Zachary Beaver, Jan Freyberg, Jonathan Deaton, Aaron Loh, Alan Karthikesalingam, Simon Kornblith, Ting Chen, et al. Big self-supervised models advance medical image classification. In Proc. ICCV, pages 3478-3488, 2021. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 311, + 151, + 547, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 151, + 547, + 194 + ], + "spans": [ + { + "bbox": [ + 311, + 151, + 547, + 194 + ], + "type": "text", + "content": "[3] Roman Bachmann, David Mizrahi, Andrei Atanov, and Amir Zamir. Multimae: Multi-modal multi-task masked autoencoders. In Proc. ECCV, pages 348-367. Springer, 2022. 2, 3, 6, 7, 8, 9" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 311, + 195, + 547, + 226 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 195, + 547, + 226 + ], + "spans": [ + { + "bbox": [ + 311, + 195, + 547, + 226 + ], + "type": "text", + "content": "[4] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. Beit: Bert pre-training of image transformers. In Proc. ICLR, 2022. 1, 2, 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 311, + 228, + 547, + 282 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 228, + 547, + 282 + ], + "spans": [ + { + "bbox": [ + 311, + 228, + 547, + 282 + ], + "type": "text", + "content": "[5] Rodrigo Bonazzola, Nishant Ravikumar, Rahman Attar, Enzo Ferrante, Tanveer Syeda-Mahmood, and Alejandro F Frangi. Image-derived phenotype extraction for genetic discovery via unsupervised deep learning in cmr images. In Proc. MICCAI, pages 699-708. Springer, 2021. 1, 2, 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 311, + 284, + 547, + 348 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 284, + 547, + 348 + ], + "spans": [ + { + "bbox": [ + 311, + 284, + 547, + 348 + ], + "type": "text", + "content": "[6] Nathaniel Braman, Jacob WH Gordon, Emery T Goossens, Caleb Willis, Martin C Stumpe, and Jagadish Venkataraman. Deep orthogonal fusion: multimodal prognostic biomarker discovery integrating radiology, pathology, genomic, and clinical data. In Proc. MICCAI, pages 667-677. Springer, 2021. 1, 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 311, + 350, + 547, + 413 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 350, + 547, + 413 + ], + "spans": [ + { + "bbox": [ + 311, + 350, + 547, + 413 + ], + "type": "text", + "content": "[7] Richard J Chen, Ming Y Lu, Jingwen Wang, Drew FK Williamson, Scott J Rodig, Neal I Lindeman, and Faisal Mahmood. Pathomic fusion: an integrated framework for fusing histopathology and genomic features for cancer diagnosis and prognosis. IEEE TMI, 41(4):757-770, 2020. 2, 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 311, + 415, + 547, + 448 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 415, + 547, + 448 + ], + "spans": [ + { + "bbox": [ + 311, + 415, + 547, + 448 + ], + "type": "text", + "content": "[8] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning of visual representations. In ICML, 2020. 2, 3, 6, 7, 9" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 311, + 449, + 547, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 449, + 547, + 491 + ], + "spans": [ + { + "bbox": [ + 311, + 449, + 547, + 491 + ], + "type": "text", + "content": "[9] Ting Chen, Simon Kornblith, Kevin Swersky, Mohammad Norouzi, and Geoffrey Hinton. Big self-supervised models are strong semi-supervised learners. In NeurlPS, 2020. 2, 7, 8" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 493, + 547, + 547 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 493, + 547, + 547 + ], + "spans": [ + { + "bbox": [ + 307, + 493, + 547, + 547 + ], + "type": "text", + "content": "[10] Xiaokang Chen, Mingyu Ding, Xiaodi Wang, Ying Xin, Shentong Mo, Yunhao Wang, Shumin Han, Ping Luo, Gang Zeng, and Jingdong Wang. Context autoencoder for self-supervised representation learning. arXiv preprint arXiv:2202.03026, 2022. 2, 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 548, + 547, + 592 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 548, + 547, + 592 + ], + "spans": [ + { + "bbox": [ + 307, + 548, + 547, + 592 + ], + "type": "text", + "content": "[11] Xinlei Chen, Saining Xie, and Kaiming He. An empirical study of training self-supervised vision transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 9640-9649, 2021. 2, 7, 8" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 593, + 547, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 593, + 547, + 635 + ], + "spans": [ + { + "bbox": [ + 307, + 593, + 547, + 635 + ], + "type": "text", + "content": "[12] Zekai Chen, Devansh Agarwal, Kshitij Aggarwal, Wiem Safta, Mariann Micsinai Balan, and Kevin Brown. Masked image modeling advances 3d medical image analysis. In Proc. WACV, 2023. 1" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 636, + 547, + 680 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 636, + 547, + 680 + ], + "spans": [ + { + "bbox": [ + 307, + 636, + 547, + 680 + ], + "type": "text", + "content": "[13] Zhihong Chen, Yuhao Du, Jinpeng Hu, Yang Liu, Guanbin Li, Xiang Wan, and Tsung-Hui Chang. Multi-modal masked autoencoders for medical vision-and-language pre-training. In Proc. MICCAI, pages 679-689. Springer, 2022. 1, 3, 6, 7" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 681, + 547, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 681, + 547, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 681, + 547, + 712 + ], + "type": "text", + "content": "[14] Jacob Cohen. Weighted kappa: nominal scale agreement provision for scaled disagreement or partial credit. *Psychol Bull*, 70(4):213, 1968. 6" + } + ] + } + ], + "index": 24 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "text", + "content": "21460" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 712 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 137 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 137 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 137 + ], + "type": "text", + "content": "[15] Jean-Bastien Grill, Florian Strub, Florent Altché, Corentin Tallec, Pierre H Richemond, Elena Buchatskaya, Carl Doersch, Bernardo Avila Pires, Zhaohan Daniel Guo, Mohammad Gheshlaghi Azar, et al. Bootstrap your own latent: A new approach to self-supervised learning. In NeurIPS, 2020. 2, 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 140, + 288, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 140, + 288, + 184 + ], + "spans": [ + { + "bbox": [ + 48, + 140, + 288, + 184 + ], + "type": "text", + "content": "[16] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dólár, and Ross Girshick. Masked autoencoders are scalable vision learners. In Proc. CVPR, pages 16000-16009, 2022. 1, 2, 3, 6, 7, 8, 9" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 185, + 288, + 218 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 185, + 288, + 218 + ], + "spans": [ + { + "bbox": [ + 48, + 185, + 288, + 218 + ], + "type": "text", + "content": "[17] Kaiming He, Haoqi Fan, Yuxin Wu, Saining Xie, and Ross Girshick. Momentum contrast for unsupervised visual representation learning. In CVPR, 2020. 2, 3, 6, 9" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 220, + 288, + 252 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 220, + 288, + 252 + ], + "spans": [ + { + "bbox": [ + 48, + 220, + 288, + 252 + ], + "type": "text", + "content": "[18] Jose Ignacio Orlando Hrvoje Bogunovic Xu Sun Jingan Liao Yanwu Xu Shaochong Zhang Huazhu Fu, Fei Li and Xiulan Zhang. Palm: Pathologic myopia challenge. 2019. 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 254, + 288, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 254, + 288, + 308 + ], + "spans": [ + { + "bbox": [ + 48, + 254, + 288, + 308 + ], + "type": "text", + "content": "[19] Ioannis Kakogeorgiou, Spyros Gidaris, Bill Psomas, Yannis Avrithis, Andrei Bursuc, Konstantinos Karantzalos, and Nikos Komodakis. What to hide from your students: Attention-guided masked image modeling. In Proc. ECCV, pages 300-318. Springer, 2022. 2, 3, 6, 7, 8, 9" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 309, + 288, + 352 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 309, + 288, + 352 + ], + "spans": [ + { + "bbox": [ + 48, + 309, + 288, + 352 + ], + "type": "text", + "content": "[20] Jacob Devlin Ming-Wei Chang Kenton and Lee Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In Proc. NAACL, pages 4171–4186, 2019. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 354, + 288, + 375 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 354, + 288, + 375 + ], + "spans": [ + { + "bbox": [ + 48, + 354, + 288, + 375 + ], + "type": "text", + "content": "[21] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. Proc. ICLR, 2015. 7" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 376, + 288, + 409 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 376, + 288, + 409 + ], + "spans": [ + { + "bbox": [ + 48, + 376, + 288, + 409 + ], + "type": "text", + "content": "[22] Günter Klambauer, Thomas Unterthiner, Andreas Mayr, and Sepp Hochreiter. Self-normalizing neural networks. In Proc. NeurIPS, volume 30, 2017. 4" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 411, + 288, + 443 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 411, + 288, + 443 + ], + "spans": [ + { + "bbox": [ + 48, + 411, + 288, + 443 + ], + "type": "text", + "content": "[23] Wuyang Li, Jie Liu, Bo Han, and Yixuan Yuan. Adjustment and alignment for unbiased open set domain adaptation. In Proc. CVPR, pages 24110-24119, 2023. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 445, + 288, + 478 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 445, + 288, + 478 + ], + "spans": [ + { + "bbox": [ + 48, + 445, + 288, + 478 + ], + "type": "text", + "content": "[24] Wuyang Li, Xinyu Liu, and Yixuan Yuan. Sigma: Semantic-complete graph matching for domain adaptive object detection. In Proc. CVPR, pages 5291-5300, 2022. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 479, + 288, + 522 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 479, + 288, + 522 + ], + "spans": [ + { + "bbox": [ + 48, + 479, + 288, + 522 + ], + "type": "text", + "content": "[25] Xiaotong Li, Yixiao Ge, Kun Yi, Zixuan Hu, Ying Shan, and Ling-Yu Duan. mc-beit: Multi-choice discretization for image bert pre-training. In Proc. ECCV, pages 231-246. Springer, 2022. 1, 2, 6, 7, 8, 9" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 523, + 288, + 545 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 523, + 288, + 545 + ], + "spans": [ + { + "bbox": [ + 48, + 523, + 288, + 545 + ], + "type": "text", + "content": "[26] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. Proc. ICLR, 2019. 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 547, + 288, + 590 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 547, + 288, + 590 + ], + "spans": [ + { + "bbox": [ + 48, + 547, + 288, + 590 + ], + "type": "text", + "content": "[27] Yang Luo, Zhineng Chen, and Xieping Gao. Self-distillation augmented masked autoencoders for histopathological image classification. arXiv preprint arXiv:2203.16983, 2022. 1, 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 592, + 288, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 592, + 288, + 645 + ], + "spans": [ + { + "bbox": [ + 48, + 592, + 288, + 645 + ], + "type": "text", + "content": "[28] Zhenyuan Ning, Denghui Du, Chao Tu, Qianjin Feng, and Yu Zhang. Relation-aware shared representation learning for cancer prognosis analysis with auxiliary clinical variables and incomplete multi-modality data. IEEE TMI, 41(1):186-198, 2021. 1, 2, 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 647, + 288, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 288, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 288, + 712 + ], + "type": "text", + "content": "[29] Samiksha Pachade, Prasanna Porwal, Dhanshree Thulkar, Manesh Kokare, Girish Deshmukh, Vivek Sahasrabuddhe, Luca Giancardo, Gwenolé Quellec, and Fabrice Mériaudeau. Retinal fundus multi-disease image dataset (rfmid): A dataset for multi-disease detection research. Data, 6(2):14, 2021. 6" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 546, + 712 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 307, + 73, + 546, + 127 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 546, + 127 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 546, + 127 + ], + "type": "text", + "content": "[30] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, Luca Antiga, et al. Pytorch: An imperative style, high-performance deep learning library. In NeurIPS, 2019. 7" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 129, + 546, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 129, + 546, + 184 + ], + "spans": [ + { + "bbox": [ + 307, + 129, + 546, + 184 + ], + "type": "text", + "content": "[31] Ryan Poplin, Avinash V Varadarajan, Katy Blumer, Yun Liu, Michael V McConnell, Greg S Corrado, Lily Peng, and Dale R Webster. Prediction of cardiovascular risk factors from retinal fundus photographs via deep learning. Nat. Biomed. Eng., 2(3):158-164, 2018. 6" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 185, + 546, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 185, + 546, + 217 + ], + "spans": [ + { + "bbox": [ + 307, + 185, + 546, + 217 + ], + "type": "text", + "content": "[32] Yu Rong, Wenbing Huang, Tingyang Xu, and Junzhou Huang. Droppedge: Towards deep graph convolutional networks on node classification. In Proc. ICLR, 2020. 5" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 220, + 546, + 273 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 220, + 546, + 273 + ], + "spans": [ + { + "bbox": [ + 308, + 220, + 546, + 273 + ], + "type": "text", + "content": "[33] Hannah Spitzer, Kai Kiwitz, Katrin Amunts, Stefan Harmeling, and Timo Dickscheid. Improving cytoarchitectonic segmentation of human brain areas with self-supervised siamese networks. In Proc. MICCAI, pages 663-671. Springer, 2018. 6" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 275, + 546, + 319 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 275, + 546, + 319 + ], + "spans": [ + { + "bbox": [ + 308, + 275, + 546, + 319 + ], + "type": "text", + "content": "[34] Aiham Taleb, Matthias Kirchler, Remo Monti, and Christoph Lippert. Contig: Self-supervised multimodal contrastive learning for medical imaging with genetics. In Proc. CVPR, pages 20908-20921, 2022. 1, 3, 6, 7, 8, 9" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 321, + 546, + 364 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 321, + 546, + 364 + ], + "spans": [ + { + "bbox": [ + 308, + 321, + 546, + 364 + ], + "type": "text", + "content": "[35] Aiham Taleb, Christoph Lippert, Tassilo Klein, and Moin Nabi. Multimodal self-supervised learning for medical image analysis. In Proc. IPMI, pages 661-673. Springer, 2021. 1, 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 365, + 546, + 409 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 365, + 546, + 409 + ], + "spans": [ + { + "bbox": [ + 308, + 365, + 546, + 409 + ], + "type": "text", + "content": "[36] Aiham Taleb, Winfried Loetzsch, Noel Danz, Julius Severin, Thomas Gaertner, Benjamin Bergner, and Christoph Lippert. 3d self-supervised methods for medical imaging. Proc. NeurIPS, 33:18158-18172, 2020. 1, 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 411, + 546, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 411, + 546, + 453 + ], + "spans": [ + { + "bbox": [ + 308, + 411, + 546, + 453 + ], + "type": "text", + "content": "[37] Katarzyna Tomczak, Patrycja Czerwińska, and Maciej Wiznerowicz. Review the cancer genome atlas (tcga): an immeasurable source of knowledge. Contemp. Oncol., 2015(1):68-77, 2015. 7" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 456, + 546, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 456, + 546, + 533 + ], + "spans": [ + { + "bbox": [ + 308, + 456, + 546, + 533 + ], + "type": "text", + "content": "[38] Rami S Vanguri, Jia Luo, Andrew T Aukerman, Jacklynn V Egger, Christopher J Fong, Nataly Horvat, Andrew Pagano, Jose de Arimateia Batista Araujo-Filho, Luke Geneslaw, Hira Rizvi, et al. Multimodal integration of radiology, pathology and genomics for prediction of response to pd-(l) 1 blockade in patients with non-small cell lung cancer. Nature cancer, 3(10):1151-1164, 2022. 1, 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 534, + 546, + 577 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 534, + 546, + 577 + ], + "spans": [ + { + "bbox": [ + 308, + 534, + 546, + 577 + ], + "type": "text", + "content": "[39] Wenguan Wang, Tianfei Zhou, Fisher Yu, Jifeng Dai, Ender Konukoglu, and Luc Van Gool. Exploring cross-image pixel contrast for semantic segmentation. In Proc. ICCV, pages 7303-7313, 2021. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 579, + 546, + 623 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 579, + 546, + 623 + ], + "spans": [ + { + "bbox": [ + 308, + 579, + 546, + 623 + ], + "type": "text", + "content": "[40] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In Proc. CVPR, pages 14668-14678, 2022. 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 624, + 546, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 624, + 546, + 668 + ], + "spans": [ + { + "bbox": [ + 308, + 624, + 546, + 668 + ], + "type": "text", + "content": "[41] LI Wuyang, YANG Chen, LIU Jie, LIU Xinyu, GUO Xiaqing, and YUAN Yixuan. Joint polyp detection and segmentation with heterogeneous endoscopic data. In Proc. ISBI Workshop, pages 69-79. CEUR-WS Team, 2021. 1" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 670, + 546, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 670, + 546, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 670, + 546, + 712 + ], + "type": "text", + "content": "[42] Junfei Xiao, Yutong Bai, Alan Yuille, and Zongwei Zhou. Delving into masked autoencoders for multi-label thorax disease classification. In Proc. WACV, pages 3588-3600, 2023. 1, 3" + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "text", + "content": "21461" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 385 + ], + "type": "list", + "angle": 0, + "index": 7, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[43] Zhenda Xie, Zheng Zhang, Yue Cao, Yutong Lin, Jianmin Bao, Zhuliang Yao, Qi Dai, and Han Hu. Simmim: A simple framework for masked image modeling. In Proc. CVPR, pages 9653-9663, 2022. 1, 2, 3, 6, 7, 8, 9" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 118, + 287, + 171 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 118, + 287, + 171 + ], + "spans": [ + { + "bbox": [ + 48, + 118, + 287, + 171 + ], + "type": "text", + "content": "[44] Xiaohan Xing, Zhen Chen, Meilu Zhu, Yuenan Hou, Zhifan Gao, and Yixuan Yuan. Discrepancy and gradient-guided multi-modal knowledge distillation for pathological glioma grading. In Proc. MICCAI, pages 636-646. Springer, 2022. 1, 3, 7" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 174, + 287, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 174, + 287, + 217 + ], + "spans": [ + { + "bbox": [ + 48, + 174, + 287, + 217 + ], + "type": "text", + "content": "[45] Qiushi Yang, Xiaqing Guo, Zhen Chen, Peter YM Woo, and Yixuan Yuan. D2-net: Dual disentanglement network for brain tumor segmentation with missing modalities. IEEE TMI, 41(10):2953-2964, 2022. 1" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 219, + 287, + 261 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 219, + 287, + 261 + ], + "spans": [ + { + "bbox": [ + 48, + 219, + 287, + 261 + ], + "type": "text", + "content": "[46] Qiushi Yang and Yixuan Yuan. Learning dynamic convolutions for multi-modal 3d mri brain tumor segmentation. In Brainlesion: MICCAI Workshop, pages 441-451. Springer, 2021. 1" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 263, + 287, + 306 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 263, + 287, + 306 + ], + "spans": [ + { + "bbox": [ + 48, + 263, + 287, + 306 + ], + "type": "text", + "content": "[47] Zhuoning Yuan, Yan Yan, Milan Sonka, and Tianbao Yang. Large-scale robust deep auc maximization: A new surrogate loss and empirical studies on medical image classification. In Proc. ICCV, pages 3040-3049, 2021. 1" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 308, + 287, + 341 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 308, + 287, + 341 + ], + "spans": [ + { + "bbox": [ + 48, + 308, + 287, + 341 + ], + "type": "text", + "content": "[48] Jinghao Zhou, Chen Wei, Huiyu Wang, Wei Shen, Cihang Xie, Alan Yuille, and Tao Kong. Image bert pre-training with online tokenizer. In Proc. ICLR, 2022. 2, 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 342, + 287, + 385 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 342, + 287, + 385 + ], + "spans": [ + { + "bbox": [ + 48, + 342, + 287, + 385 + ], + "type": "text", + "content": "[49] Lei Zhou, Huidong Liu, Joseph Bae, Junjun He, Dimitris Samaras, and Prateek Prasanna. Self pre-training with masked autoencoders for medical image analysis. arXiv preprint arXiv:2203.05573, 2022. 1, 3" + } + ] + } + ], + "index": 6 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "text", + "content": "21462" + } + ] + } + ], + "index": 8 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/6ed06787-7eb3-4534-9eb1-83af9b81cded_content_list.json b/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/6ed06787-7eb3-4534-9eb1-83af9b81cded_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..a638761ecb1aa8628a967db14117fd0c3017dd1c --- /dev/null +++ b/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/6ed06787-7eb3-4534-9eb1-83af9b81cded_content_list.json @@ -0,0 +1,1332 @@ +[ + { + "type": "text", + "text": "MRN: Multiplexed Routing Network for Incremental Multilingual Text Recognition", + "text_level": 1, + "bbox": [ + 250, + 130, + 718, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Tianlun Zheng $^{1,2}$ , Zhineng Chen $^{1,2*}$ , Bingchen Huang $^{1,2}$ , Wei Zhang $^{3}$ and Yu-Gang Jiang $^{1,2}$ \\\n $^{1}$ School of Computer Science, Fudan University, China\\\n $^{2}$ Shanghai Collaborative Innovation Center of Intelligent Visual Computing, China\\\n $^{3}$ Gaoding AI, China", + "bbox": [ + 127, + 202, + 841, + 273 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{t1zheng21, bchuang21}@m.fudan.edu.cn, {zhinchen, ygj}@fudan.edu.cn, wzhang.cu@gmail.com", + "bbox": [ + 96, + 276, + 870, + 292 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 325, + 313, + 342 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Multilingual text recognition (MLTR) systems typically focus on a fixed set of languages, which makes it difficult to handle newly added languages or adapt to ever-changing data distribution. In this paper, we propose the Incremental MLTR (IMLTR) task in the context of incremental learning (IL), where different languages are introduced in batches. IMLTR is particularly challenging due to rehearsal-imbalance, which refers to the uneven distribution of sample characters in the rehearsal set, used to retain a small amount of old data as past memories. To address this issue, we propose a Multiplexed Routing Network (MRN). MRN trains a recognizer for each language that is currently seen. Subsequently, a language domain predictor is learned based on the rehearsal set to weigh the recognizers. Since the recognizers are derived from the original data, MRN effectively reduces the reliance on older data and better fights against catastrophic forgetting, the core issue in IL. We extensively evaluate MRN on MLT17 and MLT19 datasets. It outperforms existing general-purpose IL methods by large margins, with average accuracy improvements ranging from $10.3\\%$ to $35.8\\%$ under different settings. Code is available at https://github.com/simplify23/MRN.", + "bbox": [ + 76, + 358, + 473, + 705 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 733, + 209, + 748 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Scene text recognition (STR) is a task aiming to read text in natural scenes. Recent advances in deep learning have significantly improved the accuracy of STR, allowing it to recognize text in the presence of font variations, distortions, and noise interference [39, 40, 43, 38, 19, 53]. As countries and cultures are more interconnected, the task of simultaneously recognizing multiple languages, i.e., multilingual text recognition (MLTR), has also become more important.", + "bbox": [ + 75, + 758, + 468, + 878 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/0c5aa2c85122bfbba53b92a9d91ec6ed250dfb11f4d40034fa9312614dd0c45d.jpg", + "image_caption": [ + "Figure 1. Incremental multilingual text recognition (IMLTR) focuses on the practical scenario where different languages are introduced sequentially. The goal is to accurately recognize the newly introduced language while maintaining high recognition accuracy for previously seen languages. IMLTR introduces a task focusing on text recognition that faces rehearsal-imbalance challenges." + ], + "image_footnote": [], + "bbox": [ + 511, + 325, + 882, + 501 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Existing methods typically address this challenge by training on mixed multilingual data [8, 4, 34] or designing independent language blocks [29, 22, 24]. However, when each time a new language is added, the above methods need retraining on a dataset mixing the old and new languages. This increases the training cost [37, 46] and also may lead to an imbalance [7, 14] between old and new data.", + "bbox": [ + 496, + 623, + 893, + 729 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Incremental learning (IL) is designed for scenarios where new data is continuously learned and typically, the old samples are maintained by a small ratio. The collection of old samples is referred to as the rehearsal set [51, 27], which serves as limited past memories. IL aims to learn the new data well while minimizing forgetting the past learned knowledge. Most existing studies [37, 7, 52, 28] conduct experiments on balanced datasets and maintain a constant number of classes at each learning step. However, in real-world scenarios, the number of classes and samples may differ across steps, leading to imbalanced datasets. To ad", + "bbox": [ + 496, + 734, + 893, + 900 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding Author.", + "bbox": [ + 94, + 887, + 225, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "18644", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "dress these issues, IL2M [7] alleviated class-imbalance by storing statistics of old classes rather than samples. Delange et al. De Lange et al. [14] surveyed typical IL methods on datasets and solutions with different data imbalances. Despite progress made, research on data and class imbalance is still in its infancy stage. Moreover, as illustrated in Fig. 1, there is currently no research introducing IL to STR.", + "bbox": [ + 75, + 90, + 468, + 196 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We rewrite MLTR in the context of IL. Languages are treated as tasks and characters are their classes. During training, the model only observes the newly arrived language data and a small amount of data from old languages. The recognition model is expected to maintain the ability to recognize characters of all languages that it has encountered before, regardless of whether their data are still available or discarded. We term this problem incremental multilingual text recognition (IMLTR).", + "bbox": [ + 75, + 199, + 470, + 335 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "IMLTR poses significant challenges to IL approaches due to its unbalanced features. 1) At the dataset level, it is difficult to collect sufficient training data for minority languages such as Bangla compared to popular languages such as English and Chinese, which affects the quality of recognition models. 2) At the language level, the size of character sets varies from tens to thousands across different languages, which leads to data imbalance. 3) At the character level, the occurrence frequency of characters follows a long-tailed distribution, leading to class imbalance. In addition, IMLTR faces the problem of variable length recognition, where text instances are the recognizing unit instead of character classes. Therefore, IL methods cannot sample characters as evenly as required in the context of IMLTR, resulting in a significant fraction of characters not being included in the rehearsal data, as shown in Fig. 2. This phenomenon is summarized as rehearsal-imbalance in Fig. 1. Rehearsal-imbalance leads to catastrophic forgetting, where forgotten characters cannot be recognized. Therefore, there is an urgent need to develop new methods to overcome it.", + "bbox": [ + 75, + 337, + 470, + 638 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Although the rehearsal set does not ensure full coverage of all interlingual character classes, it is still adequate for training a language domain predictor to identify the languages. Motivated by this observation, we propose a novel Multiplexed Routing Network (MRN) for IMLTR. MRN involves training a new text recognition model at each learning step and utilizing it and previously trained models for parallel feature extraction. A domain MLP router is designed to receive these features and predict the probability over the languages. Meanwhile, these features are used for character recognition in their own domain by feeding them to the multi-lingual modeling module. Finally, we fuse the results obtained at both the language domain and character levels to decode the recognized character sequence.", + "bbox": [ + 75, + 642, + 468, + 852 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Our contributions can be summarized as follows. First, we introduce the IMLTR task, the first effort to adapt IL to text recognition. It contributes to the exploration of other", + "bbox": [ + 76, + 854, + 470, + 900 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/6eea735e36321ad4fa21db70179b554d3060043fd89f66eab236167296b745d9.jpg", + "image_caption": [ + "Figure 2. The showcase of rehearsal-imbalance. Data-imbalance (top) and class-imbalance (bottom) are severely aggravated from the full dataset to the rehearsal set, while the character classes to be read remain the same, making IMLTR particularly challenging." + ], + "image_footnote": [], + "bbox": [ + 501, + 87, + 890, + 318 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "practical scenarios for text recognition. Second, we develop MRN to address the rehearsal-imbalance problem in ILMTR. It is a dynamic and scalable architecture that is compatible with various IL methods and recognition models. Third, experiments on two benchmarks show that MRN significantly outperforms existing general-purpose IL methods, achieving accuracy improvements ranging from $10.3\\%$ to $27.4\\%$ under different settings.", + "bbox": [ + 498, + 401, + 890, + 522 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 535, + 640, + 550 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Incremental Learning (IL)", + "text_level": 1, + "bbox": [ + 500, + 560, + 740, + 575 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "IL has received intensive research attention over the past few years. Typically, the problem is investigated in the context of image classification, where addressing catastrophic forgetting effectively and efficiently is its core issue. We can broadly classify existing efforts into three categories: regularization [30, 50, 15], rehearsal [36, 9, 1] and dynamic expansion [2, 46, 17, 28]. Regularization methods emphasize constraining weight changes, e.g., allowing only small magnitude changes from the previous weights. It suffers from the problem that the changes do not adequately describe the complex pattern shifts caused by new task learning. Rehearsal methods keep a small amount of old data when training a new task, thus retaining some prior knowledge. Studies in this category focus on the selection of old data and the way it is used. For example, iCaRL was developed to learn an exemplar-based data representation [37]. Alternatively, dynamic expansion methods dynamically create feature extraction sub-networks each associated with one specific task [23, 12, 45, 28]. Early methods required a task identifier to select the correct sub-network at test time. Unfortunately, the assumption is unrealistic as new sam", + "bbox": [ + 498, + 583, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "18645", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/f3c06cfdec4161fb03034253ada4f0c86080b4d294524060cd7509e0dd27f371.jpg", + "image_caption": [ + "Figure 3. An overview of MRN. In stage-I, text recognizers are trained language-by-language. While in stage-II, these recognizers are frozen for feature extraction. The Domain MLP Router, which is trained based on the rehearsal set, is proposed to predict the likelihood distribution over the languages. Meanwhile, a padded classification layer is constructed, where the parallel predicted text sequences and likelihood distributions are merged to generate the decoded character sequence." + ], + "image_footnote": [], + "bbox": [ + 81, + 89, + 890, + 395 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "plies would not come with their task identifiers. Recently, DER [46] proposed a dynamically expandable representation by discarding the task identifier, where the classifier was finetuned on a balanced exemplar subset to mitigate the task-tendency bias. It attained impressive results. Some recent works [7, 14] studied IL in inhomogeneous or uneven datasets. However, the datasets they adopted are still ideal and cannot sufficiently describe challenges in real-world problems. Moreover, there were also some studies proposed for object detection [21, 10, 48, 47], semantic segmentation [49, 16, 51] and object retrieval [32]. Text recognition has not been studied in IL so far.", + "bbox": [ + 75, + 479, + 472, + 660 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Scene Text Recognition (STR)", + "text_level": 1, + "bbox": [ + 76, + 676, + 344, + 694 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Text recognition is a longstanding research topic in computer vision and pattern recognition. Recent efforts mainly focused on recognizing text in natural scenes, i.e., STR. The task exhibits variations like text distortion, occlusion, blurring, etc., making the recognition challenging. With the advances in deep learning, especially CNN [5, 39, 26, 40] and Transformers [38, 20, 54, 43, 18, 44], STR methods have been pushed forward significantly.", + "bbox": [ + 75, + 702, + 468, + 823 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Multilingual text recognition (MLTR) is an important sub-field of STR. The most popular solution for MLTR was data-joint training [35, 8, 34, 4], where all data was gathered to train a model capable of recognizing all character classes. However, in addition to computational inten", + "bbox": [ + 75, + 824, + 470, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "sive, the approach also had the drawback of being biased toward data-rich languages, while performing poorly in minority languages where training data was scarce. As alternatives, multi-task or ensemble architectures were developed to allow data-rich languages to transfer knowledge to datapoor ones [6, 13]. They alleviated the data scarcity issue to some extent. In addition, Some studies [22, 24, 41, 29] added a script identification step to text recognition. They first identified the language domain and then selected the corresponding recognizer. Although similar to ours in the pipeline, they did not explore dependencies between languages. Moreover, none of them discussed the task within the IL framework.", + "bbox": [ + 496, + 479, + 893, + 676 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Methodology", + "text_level": 1, + "bbox": [ + 500, + 696, + 635, + 714 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Incremental Multilingual Text Recognition", + "text_level": 1, + "bbox": [ + 500, + 723, + 864, + 739 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Our goal is to develop a unified model that can recognize text instances in different languages, with the model trained incrementally language-by-language. Mathematically, assume there are $I$ kinds of languages $\\{\\mathcal{D}_1,\\dots ,\\mathcal{D}_I\\}$ , with $\\mathcal{D}_i = \\left\\{(\\mathbf{x}_{i,1},y_{i,1}),\\dots ,(\\mathbf{x}_{i,N(i)},y_{i,N(i)})\\right\\}$ as the training data at step $i$ (i.e., task $i$ ), where $x_{i,j}$ is the $j$ -th input image and $y_{i,j} \\in \\mathcal{C}_i$ is its label within the label set $\\mathcal{C}_i$ , $N(i)$ is the number of samples in set $\\mathcal{D}_i$ . At the $i$ -th learning step, samples of the $i$ -th language will be added to the training set. Therefore, the goal can be formulated as to learn", + "bbox": [ + 496, + 750, + 893, + 902 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "18646", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "new knowledge from the set $\\mathcal{D}_i$ , while retaining the previous knowledge learned from old data $\\{\\mathcal{D}_1, \\dots, \\mathcal{D}_{i-1}\\}$ . The label space of the model is all seen categories $\\tilde{\\mathcal{C}}_i = \\cup_{k=1}^i \\mathcal{C}_k$ and the model is expected to predict well on all classes in $\\tilde{\\mathcal{C}}_i$ . Note that there may be a small overlap between label sets, i.e., $\\mathcal{C}_k \\cap \\mathcal{C}_j \\neq \\emptyset$ for some $k$ and $j$ . To better fight against catastrophic forgetting, we discuss IMLTR in the rehearsal setting. That is, a small and fix-sized rehearsal set $\\mathcal{M}_i$ with a portion of samples from $\\{\\mathcal{D}_1, \\dots, \\mathcal{D}_{i-1}\\}$ is accessible at incremental step $i$ .", + "bbox": [ + 75, + 90, + 472, + 243 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Challenge and Solution Statement", + "text_level": 1, + "bbox": [ + 76, + 252, + 375, + 268 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To build a recognition model to correctly recognize text instances from all currently seen languages and their character classes, let $x_{n}$ be the text instance to be recognized. $y_{n}^{t} \\in \\tilde{\\mathcal{C}}_{i}$ denotes the $t$ -th character label corresponding to $x_{n}$ . $T(n)$ gives the total number of characters in this instance. IMLTR differs significantly from existing IL settings. For example compared to incremental image classification, standard IL usually has $|\\tilde{\\mathcal{C}}_i| \\leq 100$ and $T(n) = 1$ regardless of the value $n$ . While the size of rehearsal set $\\mathcal{M}_i$ is a constant (e.g., 2,000). However, in IMLTR $\\mathcal{C}_i$ ranges from dozens of to thousands of character classes for different languages, and $T(n)$ belongs to (1, 25), assuming 25 as the maximized length of a character sequence. Consequently, rehearsal-imbalance becomes a prominent challenge. Due to the limited size of the rehearsal set, it is not rare that a character class appears in the full dataset but is absent from the rehearsal set, as shown in Fig. 2. Thus, the incrementally trained models are likely to forget the absent character classes, despite having learned them previously, which can ultimately hurt the recognition accuracy.", + "bbox": [ + 75, + 275, + 472, + 577 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Although the rehearsal set may not be enough to train a multilingual text recognizer to identify thousands of character classes, it is still sufficient to train a language classifier to recognize the language domains present in the text instance, whose classes are a much smaller number. Once the language domains are identified, we can choose an alternative scheme that involves aggregating the results from corresponding language recognizers to perform the recognition task, thereby bypassing the rehearsal-imbalance issue.", + "bbox": [ + 75, + 578, + 468, + 713 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Motivated by this, we define $\\mathcal{H}_i$ and $\\varphi_i$ the skeleton network (all except classifier) and classifier trained at the $i$ -th incremental step. Note that $\\mathcal{H}_i$ is trained on $\\mathcal{D}_i$ , therefore can only recognize character classes of the $i$ -th language in principle. Meanwhile, $\\varphi_i$ is set to have $\\tilde{\\mathcal{C}}_i$ nodes to be compatible with typical IL settings, despite not being taught to recognize character classes of other languages. Then, we can adopt an aggregating-like scheme to implement IMLTR. The learning function can be written as:", + "bbox": [ + 75, + 713, + 468, + 849 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\sum_ {k = 1} ^ {i} \\prod_ {t = 1} ^ {T (n)} \\left(P \\left(y _ {n} ^ {t} \\mid x _ {n}; \\mathcal {H} _ {k}, \\varphi_ {k}\\right) * S \\left(d _ {n} ^ {k}\\right)\\right), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 135, + 859, + 468, + 904 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $d_n^k$ is the domain score indicating $x_{n}$ being classified as the $k$ -th language. $S(\\cdot)$ is the score quantization function, which can be a one-hot vector (hard-voting) or a likelihood distribution (soft-voting). Eq. 1 treats IMLTR as a weighted ensemble of recognition models trained based on different languages. By doing so, it successfully overcomes the rehearsal-imbalance issue within the IL framework.", + "bbox": [ + 496, + 90, + 893, + 196 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Method Overview", + "text_level": 1, + "bbox": [ + 500, + 207, + 674, + 222 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We propose a Multiplexed Routing Network (MRN) to implement this idea. As illustrated by Fig. 3, it contains two stages, i.e., individual language modeling (stage-I) and multi-lingual modeling (stage-II). In stage-I, given $\\mathcal{D}_i$ for the $i$ -th language, we train its recognizer using a popular text recognition model, which can recognize the character classes seen in $\\mathcal{D}_i$ . The model is represented as $\\mathcal{H}_i$ and $\\varphi_i$ . For character classes in $\\tilde{\\mathcal{C}}_i$ but not in $\\mathcal{C}_i$ , we simply truncate gradient propagation from these nodes thus the learned model still focuses on recognizing the $i$ -th language.", + "bbox": [ + 496, + 231, + 893, + 381 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Stage-II aims at building a multilingual routing network for IMLTR. Given a text instance $x_{n} \\in \\mathcal{D}_{i} \\cup \\mathcal{M}_{i}$ , we feed it into all the learned $i$ skeleton networks in parallel, while keeping the parameters of the networks frozen for targeted feature extraction. It extracts $i$ sets of features, each associated with a certain language. The features are further fed into a Domain MLP Router (DM-Router) module, which is designed for domain score estimation, i.e., estimating the likelihood that the text instance belongs to the languages. Meanwhile, the $i$ sets of features are fed to their respective classifiers, where the corresponding recognition character sequences are obtained. To merge their recognition, we pad the classification nodes with zeros to $|\\tilde{\\mathcal{C}}_i|$ , ensuring that all classifiers are aligned to the same dimension. As a result, their recognized characters can be merged using weighted element-wise addition, where the weights are the domain scores estimated using DM-Router. Finally, the recognition is conducted by applying a CTC- or attention-based decoding. Since DM-Router plays a critical role in the proposed method, we provide a detailed illustration below.", + "bbox": [ + 496, + 383, + 893, + 684 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.4. Domain MLP Router", + "text_level": 1, + "bbox": [ + 500, + 695, + 700, + 709 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "DM-Router uses features that are biased towards different language domains to discriminate the language domain of text instances. It accomplishes this by leveraging both the rehearsal set and the language data that arrives at the $i$ -th step. While training a separate single-network classifier, which takes an image as input and outputs the language domain scores, can identify the language domains, we believe that this approach overlooks inter-domain dependencies that could be explored for better identification. For instance, different languages may have distinct appearance patterns, such as strokes, which differ significantly between Eastern Asian languages and Latin. Additionally, their features ex", + "bbox": [ + 496, + 719, + 893, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "18647", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/5c56d96ed465594d9facb88afea3ddac6cd2695f29f26483ee5717e0268a24e3.jpg", + "image_caption": [ + "Figure 4. Detail structure of Domain MLP Router (DM-Router). Spatial-domain and Channel-domain dependencies are explored and fused to generate the language domain score distribution." + ], + "image_footnote": [], + "bbox": [ + 78, + 88, + 472, + 287 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "hibit different frequency distributions, which can also aid language identification.", + "bbox": [ + 75, + 364, + 468, + 395 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To achieve this goal, DM-Router accepts all $i$ sets of features extracted previously as input and mines the spatial-domain and channel-domain dependencies for better language identification. The detailed structure of DM-Router is shown in Fig. 4. Features from different skeleton networks are concatenated, generating a feature cubic with size $P \\times D \\times C$ , where $P$ , $D$ , and $C$ stand for the number of reshaped spatial patches, language domains, and feature channels, respectively. Then, a linear projection is applied along the channel dimension (C Proj), followed by reshaping the cubic from the patch-domain dimension. Next, a gated-mechanism is followed to generate the attention scores between the patch and domain. This is achieved by applying linear projection along the patch-domain dimension, followed by a layer norm and a feature dot product. We reshape the generated feature back to a feature cubic of the same size and merge it with the original cubic. The operations above explore the spatial-domain dependency. A similar operation is then applied to the merged feature cubic to explore the channel-domain dependence. In the following, the explored feature cubic gradually shrinks to a $D$ -dimensional score vector that indicates the probability over the languages. It represents the likelihood of each language domain for the input text instance.", + "bbox": [ + 75, + 398, + 472, + 760 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "DM-Router is an MLP-based attention network that targets language domain weighting. Note that there are a few similar solutions in the literature. Expert Gate (E-Gate) [2] developed an expert gating network that identified which model could be employed based on image reconstruction loss. However, it might not effectively discriminate IMLTR due to some languages exhibiting character class overlapping, which can cause classification confusion. On the other hand, multilingual OCR [29] determines the languages by", + "bbox": [ + 75, + 763, + 468, + 902 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/b412bbc75944f53887c670c22f92a3c7835f18ecbb24adc7d7ae779b59a406f2.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
DatasetcategoriesTask1Task2Task3Task4Task5Task6
ChineseLatinJapaneseKoreanArabicBangla
MLT17[35]train instance2687474114609563137113237
test instance5291107313501230983713
train class18953251620112473112
MLT19[34]train instance2897529215324610742303542
test instance3225882590679470393
train class20862201728116073102
", + "bbox": [ + 504, + 89, + 890, + 170 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Table 1. MLT17 and MLT19 statistics in our experiments.", + "bbox": [ + 522, + 179, + 867, + 191 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "script recognition and selected the corresponding model for recognition. Unlike these hard-voting methods, MRN employs soft-voting, which allows for the use of knowledge from other languages. For instance, Japanese has the ability to correct Chinese to some extent, given that they share some common words and similar strokes.", + "bbox": [ + 498, + 215, + 890, + 306 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.5. Training Loss", + "text_level": 1, + "bbox": [ + 500, + 314, + 643, + 330 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "MRN has two loss terms. One for multilingual text recognition while the other for language domain prediction. The total loss function is written as:", + "bbox": [ + 498, + 338, + 890, + 382 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\mathrm {c l f}} + \\alpha \\mathcal {L} _ {\\text {d o m a i n}}, \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 604, + 392, + 890, + 407 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\alpha$ is an empirical hyperparameter to balance the two.", + "bbox": [ + 498, + 417, + 890, + 431 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "MRN shows two advantages in dealing with rehearsal-imbalance. First, it ensures fair use of language. As previously mentioned, data distribution is uneven across different languages, and if not addressed during model training, it may lead to bias in the resulting model. By adopting language-by-language training and parameter freezing, data-rich and data-poor languages are treated equally, and class-imbalance is also alleviated. Second, MRN makes use of inter-lingual dependency in two ways: through the DM-Router described earlier, and through recognition score merging. When a character is recognized by more than one language, it receives confidence scores from each of them, allowing for the utilization of inter-lingual dependencies.", + "bbox": [ + 496, + 433, + 890, + 628 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 500, + 641, + 633, + 657 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Datasets and Implementation Details", + "text_level": 1, + "bbox": [ + 500, + 666, + 818, + 681 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "ICDAR 2017 MLT (MLT17) [35] has 68,613 training instances and 16,255 validation instances, which are from 6 scripts and 9 languages: Chinese, Japanese, Korean, Bangla, Arabic, Italian, English, French, and German. The last four use Latin script. The samples are from natural scenes with challenges like blur, occlusion, and distortion. We use the validation set for test due to the unavailability of test data. Tasks are split by scripts and modeled sequentially. Special symbols are discarded at the preprocessing step as with no linguistic meaning.", + "bbox": [ + 496, + 688, + 890, + 839 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "ICDAR 2019 MLT (MLT19) [34] has 89,177 text instances coming from 7 scripts. Since the inaccessibility of test set, we randomly split the training instances to 9:1 script-by-script, for model training and test. To be consistent with", + "bbox": [ + 496, + 839, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "18648", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/35885533769ba6c3cd038ea568353d9bb0c12550006ae9af2e6b51ca9733ccff.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MLT17MLT19
Model: CRNN (TPAMI'17) [39]
T1T2T3T4T5T6AVGT1T2T3T4T5T6AVG
Bound------92.1------84.9
Baseline91.151.751.037.229.322.347.185.149.646.535.527.620.744.2
LwF (TPAMI'17)[31]91.153.753.438.229.723.748.385.151.649.236.527.722.045.3
EWC (PNAS'17)[30]91.156.550.437.230.521.547.985.155.546.335.828.819.945.2
WA (CVPR'20) [52]91.154.648.738.228.523.147.485.152.244.336.726.821.644.4
DER (CVPR'21)[46]91.176.355.846.439.335.857.585.175.240.445.136.634.252.8
MRN91.188.677.273.769.869.878.485.185.173.268.365.365.573.7
Model: TRBA (ICCV'19) [3]
T1T2T3T4T5T6AVGT1T2T3T4T5T6AVG
Bound------94.9------90.5
Baseline91.349.647.336.128.624.046.185.449.444.034.827.423.144.0
LwF (TPAMI'17)[31]91.355.738.828.722.618.742.685.454.235.027.220.517.039.9
EWC (PNAS'17)[30]91.350.443.633.125.621.944.385.449.440.631.724.820.642.1
WA (CVPR'20) [52]91.345.441.830.723.519.642.185.444.037.929.221.618.139.4
DER (CVPR'21)[46]91.360.153.038.831.428.650.585.460.750.337.230.328.148.7
MRN91.387.975.872.271.568.777.985.484.573.267.866.764.873.7
Model: SVTR-Base (IJCAI'22) [18]
T1T2T3T4T5T6AVGT1T2T3T4T5T6AVG
Bound------90.1------83.2
Baseline90.632.540.530.824.519.939.884.831.337.029.222.619.137.3
LwF (TPAMI'17)[31]90.628.038.429.924.118.338.284.827.034.628.422.317.035.7
EWC (PNAS'17)[30]90.633.041.231.124.620.040.184.831.337.729.522.619.037.5
WA (CVPR'20) [52]90.628.037.930.424.819.838.684.826.734.628.322.618.635.9
DER (CVPR'21)[46]90.674.555.755.049.545.761.884.871.652.952.246.643.658.6
MRN90.686.473.965.663.458.173.084.883.769.464.457.853.168.9
", + "bbox": [ + 101, + 87, + 867, + 483 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2. Accuracy (%) of different text recognizers and incremental learning methods on MLT17 and MLT19. Baseline denotes the model trained solely based on the rehearsal set and language data arrived at that step. The language incremental order is introduced in Sec. 4.1.", + "bbox": [ + 75, + 494, + 890, + 523 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "MLT2017 dataset, we discard the Hindi script and also special symbols. Statistics of the two datasets are shown Tab. 1.", + "bbox": [ + 75, + 547, + 468, + 577 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Height and width of the images are scaled uniformly to $32 \\times 256$ . The maximum length of a character sequence is set to 25. All models, each corresponding to a language domain, are trained with 10,000 iterations, using the Adam optimizer and the one-cycle learning rate scheduler [42] with a maximum learning rate of 0.0005. The batch size is set to 256. To mitigate the dataset variance, in each batch we evenly sample training samples from both datasets, that is, half from MLT17 and half from MLT19. A random order for the six languages is employed, which is Chinese, Latin, Japanese, Korean, Arabic, Bangla. Other orders will be discussed later. For the rehearsal setting, we limit the rehearsal size to 2000 samples unless specified. We conduct the experiments using two NVIDIA RTX 3090 GPUs.", + "bbox": [ + 75, + 578, + 468, + 789 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Comparison with Existing Methods", + "text_level": 1, + "bbox": [ + 76, + 801, + 385, + 816 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We equip MRN with different text recognizers and combine them with different IL methods. Specifically, we consider three typical STR schemes: CTC-based (CRNN [39]), attention-based (TRBA [3]), and ViT-based (SVTR [18]). Meanwhile, four popular IL methods are chosen, i.e., Lwf", + "bbox": [ + 75, + 825, + 470, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "[31], EWC [30], WA [52] and DER [46]. All models retain their original settings, except for the removal of the auxiliary loss of DER, which reduces its performance in our task.", + "bbox": [ + 498, + 547, + 890, + 593 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In Tab. 2, we give the results at different incremental steps, where the language is added one-by-one and the average accuracy of different methods is reported. Bound, the model trained using all training data, is also listed as the oracle for reference. As can be seen, MRN consistently outperforms all the compared methods by significant margins under different settings, no matter which recognizer is employed. When looking into the general-purpose IL methods, their accuracy mostly decreased rapidly as the incremental steps due to the affection of rehearsal-imbalance. DER has the highest accuracy among them, as its dynamic expansion architecture has certain advantages in fighting against catastrophic forgetting. However, there is still a clear accuracy gap between DER and our MRN, and the gap widens as the incremental step increases. We attribute the accuracy improvement achieved by MRN to two factors. First, IMLTR is a task that differs significantly from image classification, where most IL methods have been experimented on. These methods do not well accommodate the challenge raised by IMLTR. For example, the rehearsal-imbalance issue. Sec-", + "bbox": [ + 496, + 598, + 892, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "18649", + "bbox": [ + 480, + 945, + 519, + 955 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "ond, MRN develops an elegant pipeline that implements the recognition in a domain routing and result fusion manner. It works particularly well for scenarios where incremental tasks exhibit significant differences.", + "bbox": [ + 75, + 90, + 468, + 151 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "When comparing the recognizers, MRN equipped with CRNN has the highest overall accuracy. The result is interesting as CRNN has a simpler architecture and generally performs worse than the other two methods on typical STR tasks. We attribute this to parameter freezing, where the feature extraction backbone (e.g., $\\mathcal{H}_i$ ) and the decoder cannot be jointly optimized. Therefore, advanced models are more severely affected, while the simpler one is less affected and can better mitigate catastrophic forgetting.", + "bbox": [ + 75, + 151, + 470, + 287 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/2b190f3573e2727922f90ede742c2bd3480c73f3483c0b310c95a2c42762ca18.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
modelMLT17MLT19
AvgLastAvgLast
None64.837.960.835.6
MLP68.560.565.356.3
CycleMLP[11]75.563.571.160.0
ViP[25]76.462.672.259.6
gMLP[33]77.568.273.164.2
DM-Router78.469.873.865.5
", + "bbox": [ + 116, + 297, + 431, + 422 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 469, + 230, + 486 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We perform a series of controlled experiments to gain a deeper understanding of MRN. CRNN is employed as the text recognizer unless specified.", + "bbox": [ + 75, + 493, + 468, + 537 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Effectiveness of DM-Router: There are multiple ways to deduce the language domain scores. We enumerate several of them that have been used in existing studies, as shown in Tab. 3. None denotes no dependence is explored, which corresponds to the worst result. It, in turn, demonstrates the necessity of utilizing language dependence. Among the rest competitors, MLP enables a naive learning mechanism while the remaining three are based on more advanced MLP-like models, which are typically more effective. Despite this, DM-Router attains the highest accuracy among the methods. The results clearly demonstrate the rationality of the DM-Router structure in terms of language dependence exploration.", + "bbox": [ + 75, + 537, + 470, + 734 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Influence of the size of the rehearsal set: We conduct analytical experiments to evaluate the influence of the rehearsal size on the accuracy of Lwf [31], DER [46] and MRN. Fig. 4 shows the accuracy under different rehearsal sizes. As anticipated, increasing the rehearsal set size leads to accuracy gains, as more past memories are retained. We observe that larger gains are obtained in LwF and DER, particularly DER. This reveals the accuracy of general-purpose IL methods is largely affected by the rehearsal size in IMLTR, while MRN is less affected. MRN has already achieved relatively high accuracy, and the performance of MRN in iden", + "bbox": [ + 75, + 734, + 470, + 901 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/fc2a52468ad5aa5957151ca4830e92b91d3aa80f70bb6abbf3537f9590cc32b4.jpg", + "table_caption": [ + "Table 3. Performance comparisons on different MLP models." + ], + "table_footnote": [], + "table_body": "
SizeMethodMLT17MLT19
AvgLastAvgLast
2kLwF[31]48.323.745.422.0
DER[46]57.535.852.834.2
MRN78.469.873.865.5
3kLwF[31]52.224.948.823.6
DER[46]60.942.058.740.6
MRN80.272.775.468.2
4kLwF[31]55.527.552.226.1
DER[46]66.448.763.846.6
MRN81.575.076.570.6
", + "bbox": [ + 542, + 88, + 854, + 252 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/2f94bdf97610a43f677b5e633727dff786c03ea73552d1945b36158b15c857aa.jpg", + "table_caption": [ + "Table 4. Ablation study on the size of the rehearsal set." + ], + "table_footnote": [], + "table_body": "
OrderMethodMLT17MLT19
AvgLastAvgLast
O1LwF[31]48.323.745.422.0
DER[46]57.535.852.834.2
MRN78.469.873.865.5
O2LwF[31]46.923.843.122.9
DER[46]63.139.158.739.6
MRN80.565.374.161.5
O3LwF[31]57.734.755.734.2
DER[46]69.641.365.738.2
MRN82.970.678.366.0
", + "bbox": [ + 529, + 287, + 862, + 460 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/865305e745df1dfe3f43685416fcb388c835b507d4303acbcd4231502c19f30f.jpg", + "table_caption": [ + "Table 5. Ablation study on language order." + ], + "table_footnote": [], + "table_body": "
Sampling StrategyMLT17MLT19
AvgLastAvgLast
Confidence56.443.854.041.2
Length71.050.366.648.9
Frequency72.656.667.853.7
Random78.469.873.865.5
", + "bbox": [ + 527, + 497, + 864, + 594 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 6. Ablation study on rehearsal sampling strategy.", + "bbox": [ + 531, + 603, + 859, + 618 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "tifying language domains is less affected by the rehearsal size. The results indicate that MRN is robust to rehearsal scarcity and can better fight against data imbalance.", + "bbox": [ + 496, + 642, + 890, + 686 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Influence of language incremental order: In addition to the order in Sec. 4.1 (O1), we assess two other orders as follows: 1) Arabic, Chinese, Latin, Japanese, Bangla, Korean (O2); 2) Latin, Arabic, Bangla, Chinese, Japanese, Korean (O3). The two orders either alternate the three Eastern Asia languages, which have large vocabularies and show more stroke commonalities, or group them together at the end. We also include Lwf and DER for comparison.", + "bbox": [ + 496, + 688, + 890, + 808 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Tab. 5 gives the results and two observations. First, O3 shows the best accuracy, while O2 also performs better than O1. It is because the three Eastern Asia languages are more difficult to recognize due to their large vocabulary sizes, therefore introducing them later leads to a better average accuracy. Meanwhile, putting them together also reduces the", + "bbox": [ + 496, + 810, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "18650", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/d625bc6d5dcd55ea01f31d80914b8b9abfa7ce40b4550e628e7a918c7ad9592d.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodSelectModelVotingMLT17MLT19Params (M)FLOPs (G)
AvgLastAvgLast
Baseline---47.122.344.220.79.53.5
DER[46]---57.535.852.834.233.812.3
E-Gate[2]Re-Const.AutoencoderHard37.215.234.814.232.512.2
E-Gate[2]StackingAutoencoderHard62.715.259.314.235.512.4
MRNStackingDM-RouterHard74.462.969.957.733.512.4
MRNStackingDM-RouterSoft78.469.873.865.533.512.4
", + "bbox": [ + 163, + 88, + 812, + 202 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 7. Comparisons on different routing strategies.", + "bbox": [ + 326, + 210, + 640, + 226 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "oscillation during parameter learning and generates a better model, due to their stroke commonalities. The experiment suggests that careful selection of the order of languages can attain better accuracy. Second, O1 shows the largest accuracy gaps between MRN and other methods. This is because in O1, the large vocabulary languages appear earlier, while the rehearsal set is fix-sized, resulting in the most severe class imbalance among the three orders. The result indicates that MRN can better handle class imbalance.", + "bbox": [ + 75, + 250, + 468, + 385 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Influence of rehearsal sampling strategy: The determination of text instances being sampled to the rehearsal set is an issue also worthy of abulating. Tab. 6 gives the accuracy of four sampling strategies, i.e., Confidence that selects instances with the highest recognition scores, Length that selects instances with the largest number of characters, Frequency that selects instances with the most frequently occurred characters, and Random adopted in our MRN that randomly selects the instances. Interestingly, Random gives the best accuracy. We attribute the reason to: the rehearsal set obtained from Confidence or Frequency cannot fully represent the true data distribution, where difficult or less occurred instances are excluded. Length, to some extent, overlooks the varying-length characteristic of IMLTR. On the contrary, Random, despite simple, well mimics the underlying data distribution and well handles the variable length challenge.", + "bbox": [ + 75, + 386, + 470, + 642 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Comparison on routing strategy: We compare MRN with E-Gate and its variants. E-Gate [2] treats different subnetworks as experts, and each time selects the most appropriate one for inference. In Tab. 7 we provide the model details. Raw E-Gate performs poorly in IMLTR. When stacking is used to build feature extractors, the accuracy improves significantly and outperforms DER. We also evaluate MRN with hard-voting. It reports a worse result. Compared to other routing strategies, our MRN shows clear superiority in terms of accuracy, while incurring only a negligible cost in parameters and computational complexity.", + "bbox": [ + 75, + 643, + 470, + 811 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.4. Qualitative Results Analysis", + "text_level": 1, + "bbox": [ + 76, + 816, + 328, + 832 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Fig. 5 gives several recognition results of MRN. It correctly read instances of different languages, even with the presence of common recognition difficulties. More importantly, MRN also recognizes character classes that are not", + "bbox": [ + 75, + 839, + 470, + 902 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/a5ec3628cc6be67d97e1f80b18bad2db4fc01b96eb6ed3e3c4933d976f9731a3.jpg", + "image_caption": [ + "Figure 5. Illustrative recognition examples, where red denotes characters that are absent from the rehearsal set." + ], + "image_footnote": [], + "bbox": [ + 514, + 250, + 879, + 444 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "present in the rehearsal set. These results again demonstrate that our MRN is effective in handling rehearsal-imbalance and can generalize well to unseen character classes.", + "bbox": [ + 498, + 500, + 890, + 544 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 560, + 619, + 575 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this work, we introduce a new task called incremental multilingual text recognition (IMLTR). IMLTR handles text recognition in an incremental learning setting, therefore is suitable for applications like streaming data processing. IMLTR faces a distinct problem of rehearsal-imbalance, including data imbalance, class imbalance, and variable character length. To address this challenge, we designed a Multiplexed Routing Network (MRN) that first trains a multi-language correlated DM-router to weight the language domains, and then votes the separately trained recognition branches for final text recognition. Experiments on public benchmarks show that MRN significantly outperforms existing general-purpose IL methods by large margins. As the first attempt to apply IL to multilingual text recognition, we hope that this work will broaden the applications of text recognition and inspire further research in this area.", + "bbox": [ + 496, + 587, + 890, + 829 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgments This project was supported by National Key R&D Program of China (No. 2022YFB3104703) and in part by the National Natural Science Foundation of China (No. 62172103)", + "bbox": [ + 498, + 839, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "18651", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Rahaf Aljundi, Francesca Babiloni, Mohamed Elhoseiny, Marcus Rohrbach, and Tinne Tuytelaars. Memory aware synapses: Learning what (not) to forget. In ECCV, pages 139-154, 2018. 2", + "[2] Rahaf Aljundi, Punarjay Chakravarty, and Tinne Tuytelaars. Expert gate: Lifelong learning with a network of experts. In CVPR, July 2017. 2, 5, 8", + "[3] Jeonghun Baek, Geewook Kim, Junyeop Lee, Sungrae Park, Dongyoon Han, Sangdoo Yun, Seong Joon Oh, and Hwalsuk Lee. What is wrong with scene text recognition model comparisons? dataset and model analysis. In ICCV, pages 4714-4722, 2019. 6", + "[4] Youngmin Baek, Seung Shin, Jeonghun Baek, Sungrae Park, Junyeop Lee, Daehyun Nam, and Hwalsuk Lee. Character region attention for text spotting. In ECCV, pages 504-521. Springer, 2020. 1, 3", + "[5] Jinfeng Bai, Zhineng Chen, Bailan Feng, and Bo Xu. Chinese image text recognition on grayscale pixels. In 2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), pages 1380-1384. IEEE, 2014. 3", + "[6] Jinfeng Bai, Zhineng Chen, Bailan Feng, and Bo Xu. Image character recognition using deep convolutional neural network learned from different languages. In 2014 IEEE International Conference on Image Processing (ICIP), pages 2560-2564. IEEE, 2014. 3", + "[7] Eden Belouadah and Adrian Popescu. II2m: Class incremental learning with dual memory. In ICCV, pages 583-592, 2019. 1, 2, 3", + "[8] Michal Bušta, Yash Patel, and Jiri Matas. E2e-plt-an unconstrained end-to-end method for multi-language scene text. In ACCV, pages 127–143. Springer, 2018. 1, 3", + "[9] Francisco M Castro, Manuel J Marín-Jiménez, Nicolás Guil, Cordelia Schmid, and Karteek Alahari. End-to-end incremental learning. In ECCV, pages 233-248, 2018. 2", + "[10] Li Chen, Chunyan Yu, and Lvcai Chen. A new knowledge distillation for incremental object detection. In IJCNN, pages 1-7. IEEE, 2019. 3", + "[11] Shoufa Chen, Enze Xie, Chongjian GE, Runjian Chen, Ding Liang, and Ping Luo. CycleMLP: A MLP-like architecture for dense prediction. In ICLR, 2022. 7", + "[12] Mark Collier, Efi Kokiopoulou, Andrea Gesmundo, and Jesse Berent. Routing networks with co-training for continual learning. ICML, 2020. 2", + "[13] Jia Cui, Brian Kingsbury, Bhuvana Ramabhadran, George Saon, Tom Sercu, Kartik Audhkhasi, Abhinav Sethy, Markus Nussbaum-Thom, and Andrew Rosenberg. Knowledge distillation across ensembles of multilingual models for low-resource languages. In ICASSP, pages 4825-4829, 2017. 3", + "[14] Matthias De Lange, Rahaf Aljundi, Marc Masana, Sarah Parisot, Xu Jia, Aleš Leonardis, Gregory Slabaugh, and Tinne Tuytelaars. A continual learning survey: Defying forgetting in classification tasks. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(7):3366-3385, 2022. 1, 2, 3" + ], + "bbox": [ + 78, + 114, + 468, + 898 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[15] Prithviraj Dhar, Rajat Vikram Singh, Kuan-Chuan Peng, Ziyan Wu, and Rama Chellappa. Learning without memorizing. In CVPR, pages 5138-5146, 2019. 2", + "[16] Arthur Douillard, Yifu Chen, Arnaud Dapogny, and Matthieu Cord. Plop: Learning without forgetting for continual semantic segmentation. In CVPR, pages 4040-4050, 2021. 3", + "[17] Arthur Douillard, Alexandre Ramé, Guillaume Couairon, and Matthieu Cord. Dytox: Transformers for continual learning with dynamic token expansion. In CVPR, pages 9285–9295, 2022. 2", + "[18] Yongkun Du, Zhineng Chen, Caiyan Jia, Xiaoting Yin, Tianlun Zheng, Chenxia Li, Yuning Du, and Yu-Gang Jiang. SVTR: scene text recognition with a single visual model. In IJCAI, 2022. 3, 6", + "[19] Shancheng Fang, Zhendong Mao, Hongtao Xie, Yuxin Wang, Chenggang Yan, and Yongdong Zhang. Abinet++: Autonomous, bidirectional and iterative language modeling for scene text spotting. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 1", + "[20] Shancheng Fang, Hongtao Xie, Yuxin Wang, Zhendong Mao, and Yongdong Zhang. Read like humans: Autonomous, bidirectional and iterative language modeling for scene text recognition. In CVPR, pages 7094-7103, 2021. 3", + "[21] Tao Feng, Mang Wang, and Hangjie Yuan. Overcoming catastrophic forgetting in incremental object detection via elastic response distillation. In CVPR, pages 9427-9436, 2022. 3", + "[22] Yasuhisa Fujii, Karel Driesen, Jonathan Baccash, Ash Hurst, and Ashok C Popat. Sequence-to-label script identification for multilingualOCR. In ICDAR, volume 1, pages 161-168. IEEE, 2017. 1, 3", + "[23] Siavash Golkar, Michael Kagan, and Kyunghyun Cho. Continual learning via neural pruning. NIPS, 2019. 2", + "[24] Lluis Gomez, Anguelos Nicolaou, and Dimosthenis Karatzas. Improving patch-based scene text script identification with ensembles of conjoined networks. Pattern Recognition, 67:85-96, 2017. 1, 3", + "[25] Qibin Hou, Zihang Jiang, Li Yuan, Ming-Ming Cheng, Shuicheng Yan, and Jiashi Feng. Vision permutator: A permutable mlp-like architecture for visual recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 7", + "[26] Wenyang Hu, Xiaocong Cai, Jun Hou, Shuai Yi, and Zhiping Lin. Gtc: Guided training of ctc towards efficient and accurate scene text recognition. In AAAI, volume 34, pages 11005-11012, 2020. 3", + "[27] Xinting Hu, Kaihua Tang, Chunyan Miao, Xian-Sheng Hua, and Hanwang Zhang. Distilling causal effect of data in class incremental learning. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3957-3966, 2021. 1", + "[28] Bingchen Huang, Zhineng Chen, Peng Zhou, Jiayin Chen, and Zuxuan Wu. Resolving task confusion in dynamic expansion architectures for class incremental learning. In AAAI, volume 37, pages 908-916, 2023. 1, 2" + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "18652", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[29] Jing Huang, Guan Pang, Rama Kovvuri, Mandy Toh, Kevin J Liang, Praveen Krishnan, Xi Yin, and Tal Hassner. A multiplexed network for end-to-end, multilingualOCR. In CVPR, pages 4547-4557, 2021. 1, 3, 5", + "[30] James Kirkpatrick, Razvan Pascanu, Neil Rabinowitz, Joel Veness, Guillaume Desjardins, Andrei A Rusu, Kieran Milan, John Quan, Tiago Ramalho, Agnieszka Grabska-Barwinska, et al. Overcoming catastrophic forgetting in neural networks. Proceedings of the national academy of sciences, 114(13):3521-3526, 2017. 2, 6", + "[31] Zhizhong Li and Derek Hoiem. Learning without forgetting. IEEE transactions on pattern analysis and machine intelligence, 40(12):2935-2947, 2017. 6, 7", + "[32] An-An Liu, Haochun Lu, Heyu Zhou, Tianbao Li, and Mohan Kankanhalli. Balanced class-incremental 3d object classification and retrieval. IEEE Transactions on Knowledge and Data Engineering, 2023. 3", + "[33] Hanxiao Liu, Zihang Dai, David So, and Quoc V Le. Pay attention to mlps. NIPS, 34:9204-9215, 2021. 7", + "[34] Nibal Nayef, Yash Patel, Michal Busta, Pinaki Nath Chowdhury, Dimosthenis Karatzas, Wafa Khlif, Jiri Matas, Umapada Pal, Jean-Christophe Burie, Cheng-lin Liu, et al. Icdar2019 robust reading challenge on multi-lingual scene text detection and recognition—rrc-plt-2019. In ICDAR, pages 1582–1587. IEEE, 2019. 1, 3, 5", + "[35] Nibal Nayef, Fei Yin, Imen Bizid, Hyunsoo Choi, Yuan Feng, Dimosthenis Karatzas, Zhenbo Luo, Umapada Pal, Christophe Rigaud, Joseph Chazalon, et al. Icdar2017 robust reading challenge on multi-lingual scene text detection and script identification-rrc-plt. In ICDAR, volume 1, pages 1454-1459. IEEE, 2017. 3, 5", + "[36] German I Parisi, Ronald Kemker, Jose L Part, Christopher Kanan, and Stefan Wermter. Continual lifelong learning with neural networks: A review. Neural Networks, 113:54-71, 2019. 2", + "[37] Sylvestre-Alvise Rebuffi, Alexander Kolesnikov, Georg Sperl, and Christoph H Lampert. icarl: Incremental classifier and representation learning. In CVPR, pages 2001–2010, 2017. 1, 2", + "[38] Fenfen Sheng, Zhineng Chen, and Bo Xu. Ntrr: A no-recurrence sequence-to-sequence model for scene text recognition. In ICDAR, pages 781-786, 2019. 1, 3", + "[39] Baoguang Shi, Xiang Bai, and Cong Yao. An end-to-end trainable neural network for image-based sequence recognition and its application to scene text recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 39(11):2298-2304, 2017. 1, 3, 6", + "[40] Baoguang Shi, Mingkun Yang, Xinggang Wang, Pengyuan Lyu, Cong Yao, and Xiang Bai. Aster: An attentional scene text recognizer with flexible rectification. IEEE Transactions on Pattern Analysis and Machine Intelligence, 41(9):2035-2048, 2018. 1, 3", + "[41] Baoguang Shi, Cong Yao, Chengquan Zhang, Xiaowei Guo, Feiyue Huang, and Xiang Bai. Automatic script identification in the wild. In ICDAR, pages 531-535. IEEE, 2015. 3", + "[42] Leslie N Smith and Nicholay Topin. Super-convergence: Very fast training of neural networks using large learning" + ], + "bbox": [ + 78, + 90, + 468, + 901 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "rates. In Artificial intelligence and machine learning for multi-domain operations applications, volume 11006, pages 369-386. SPIE, 2019. 6", + "[43] Yuxin Wang, Hongtao Xie, Shancheng Fang, Jing Wang, Shenggao Zhu, and Yongdong Zhang. From two to one: A new scene text recognizer with visual language modeling network. In ICCV, pages 14174-14183, 2021. 1, 3", + "[44] Yuxin Wang, Hongtao Xie, Shancheng Fang, Mengting Xing, Jing Wang, Shenggao Zhu, and Yongdong Zhang. Petr: Rethinking the capability of transformer-based language model in scene text recognition. IEEE Transactions on Image Processing, 31:5585-5598, 2022. 3", + "[45] Yeming Wen, Dustin Tran, and Jimmy Ba. Batchsemble: an alternative approach to efficient ensemble and lifelong learning. In ICLR, 2020. 2", + "[46] Shipeng Yan, Jiangwei Xie, and Xuming He. Der: Dynamically expandable representation for class incremental learning. In CVPR, pages 3014-3023, 2021. 1, 2, 3, 6, 7, 8", + "[47] Dongbao Yang, Yu Zhou, Xiaopeng Hong, Aoting Zhang, and Weiping Wang. One-shot replay: Boosting incremental object detection via retrospecting one object. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 37, pages 3127-3135, 2023. 3", + "[48] Dongbao Yang, Yu Zhou, Aoting Zhang, Xurui Sun, Dayan Wu, Weiping Wang, and Qixiang Ye. Multi-view correlation distillation for incremental object detection. Pattern Recognition, 131:108863, 2022. 3", + "[49] Guanglei Yang, Enrico Fini, Dan Xu, Paolo Rota, Mingli Ding, Moin Nabi, Xavier Alameda-Pineda, and Elisa Ricci. Uncertainty-aware contrastive distillation for incremental semantic segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 3", + "[50] Friedemann Zenke, Ben Poole, and Surya Ganguli. Continual learning through synaptic intelligence. In ICML, pages 3987-3995. PMLR, 2017. 2", + "[51] Chang-Bin Zhang, Jia-Wen Xiao, Xialei Liu, Ying-Cong Chen, and Ming-Ming Cheng. Representation compensation networks for continual semantic segmentation. In CVPR, pages 7053-7064, 2022. 1, 3", + "[52] Bowen Zhao, Xi Xiao, Guojun Gan, Bin Zhang, and Shu-Tao Xia. Maintaining discrimination and fairness in class incremental learning. In CVPR, pages 13208-13217, 2020. 1, 6", + "[53] Tianlun Zheng, Zhineng Chen, Jinfeng Bai, Hongtao Xie, and Yu-Gang Jiang. Tps++: Attention-enhanced thin-plate spline for scene text recognition. *IJCAI*, 2023. 1", + "[54] Tianlun Zheng, Zhineng Chen, Shancheng Fang, Hongtao Xie, and Yu-Gang Jiang. Cdistnet: Perceiving multi-domain character distance for robust text recognition. arXiv preprint arXiv:2111.11011, 2021. 3" + ], + "bbox": [ + 503, + 92, + 890, + 797 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "18653", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/6ed06787-7eb3-4534-9eb1-83af9b81cded_model.json b/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/6ed06787-7eb3-4534-9eb1-83af9b81cded_model.json new file mode 100644 index 0000000000000000000000000000000000000000..8fa3204c3568ff89b83df5840507ee8ff4794f1a --- /dev/null +++ b/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/6ed06787-7eb3-4534-9eb1-83af9b81cded_model.json @@ -0,0 +1,1914 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.251, + 0.131, + 0.72, + 0.177 + ], + "angle": 0, + "content": "MRN: Multiplexed Routing Network for Incremental Multilingual Text Recognition" + }, + { + "type": "text", + "bbox": [ + 0.128, + 0.203, + 0.842, + 0.275 + ], + "angle": 0, + "content": "Tianlun Zheng\\(^{1,2}\\), Zhineng Chen\\(^{1,2*}\\), Bingchen Huang\\(^{1,2}\\), Wei Zhang\\(^{3}\\) and Yu-Gang Jiang\\(^{1,2}\\)\\\n\\(^{1}\\)School of Computer Science, Fudan University, China\\\n\\(^{2}\\)Shanghai Collaborative Innovation Center of Intelligent Visual Computing, China\\\n\\(^{3}\\)Gaoding AI, China" + }, + { + "type": "text", + "bbox": [ + 0.098, + 0.277, + 0.872, + 0.293 + ], + "angle": 0, + "content": "{t1zheng21, bchuang21}@m.fudan.edu.cn, {zhinchen, ygj}@fudan.edu.cn, wzhang.cu@gmail.com" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.327, + 0.314, + 0.343 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.359, + 0.474, + 0.707 + ], + "angle": 0, + "content": "Multilingual text recognition (MLTR) systems typically focus on a fixed set of languages, which makes it difficult to handle newly added languages or adapt to ever-changing data distribution. In this paper, we propose the Incremental MLTR (IMLTR) task in the context of incremental learning (IL), where different languages are introduced in batches. IMLTR is particularly challenging due to rehearsal-imbalance, which refers to the uneven distribution of sample characters in the rehearsal set, used to retain a small amount of old data as past memories. To address this issue, we propose a Multiplexed Routing Network (MRN). MRN trains a recognizer for each language that is currently seen. Subsequently, a language domain predictor is learned based on the rehearsal set to weigh the recognizers. Since the recognizers are derived from the original data, MRN effectively reduces the reliance on older data and better fights against catastrophic forgetting, the core issue in IL. We extensively evaluate MRN on MLT17 and MLT19 datasets. It outperforms existing general-purpose IL methods by large margins, with average accuracy improvements ranging from \\(10.3\\%\\) to \\(35.8\\%\\) under different settings. Code is available at https://github.com/simplify23/MRN." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.734, + 0.21, + 0.749 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.759, + 0.47, + 0.88 + ], + "angle": 0, + "content": "Scene text recognition (STR) is a task aiming to read text in natural scenes. Recent advances in deep learning have significantly improved the accuracy of STR, allowing it to recognize text in the presence of font variations, distortions, and noise interference [39, 40, 43, 38, 19, 53]. As countries and cultures are more interconnected, the task of simultaneously recognizing multiple languages, i.e., multilingual text recognition (MLTR), has also become more important." + }, + { + "type": "image", + "bbox": [ + 0.512, + 0.326, + 0.883, + 0.502 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.506, + 0.895, + 0.59 + ], + "angle": 0, + "content": "Figure 1. Incremental multilingual text recognition (IMLTR) focuses on the practical scenario where different languages are introduced sequentially. The goal is to accurately recognize the newly introduced language while maintaining high recognition accuracy for previously seen languages. IMLTR introduces a task focusing on text recognition that faces rehearsal-imbalance challenges." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.624, + 0.894, + 0.731 + ], + "angle": 0, + "content": "Existing methods typically address this challenge by training on mixed multilingual data [8, 4, 34] or designing independent language blocks [29, 22, 24]. However, when each time a new language is added, the above methods need retraining on a dataset mixing the old and new languages. This increases the training cost [37, 46] and also may lead to an imbalance [7, 14] between old and new data." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Incremental learning (IL) is designed for scenarios where new data is continuously learned and typically, the old samples are maintained by a small ratio. The collection of old samples is referred to as the rehearsal set [51, 27], which serves as limited past memories. IL aims to learn the new data well while minimizing forgetting the past learned knowledge. Most existing studies [37, 7, 52, 28] conduct experiments on balanced datasets and maintain a constant number of classes at each learning step. However, in real-world scenarios, the number of classes and samples may differ across steps, leading to imbalanced datasets. To ad" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.888, + 0.227, + 0.9 + ], + "angle": 0, + "content": "*Corresponding Author." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "18644" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.091, + 0.47, + 0.198 + ], + "angle": 0, + "content": "dress these issues, IL2M [7] alleviated class-imbalance by storing statistics of old classes rather than samples. Delange et al. De Lange et al. [14] surveyed typical IL methods on datasets and solutions with different data imbalances. Despite progress made, research on data and class imbalance is still in its infancy stage. Moreover, as illustrated in Fig. 1, there is currently no research introducing IL to STR." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.2, + 0.471, + 0.336 + ], + "angle": 0, + "content": "We rewrite MLTR in the context of IL. Languages are treated as tasks and characters are their classes. During training, the model only observes the newly arrived language data and a small amount of data from old languages. The recognition model is expected to maintain the ability to recognize characters of all languages that it has encountered before, regardless of whether their data are still available or discarded. We term this problem incremental multilingual text recognition (IMLTR)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.338, + 0.471, + 0.64 + ], + "angle": 0, + "content": "IMLTR poses significant challenges to IL approaches due to its unbalanced features. 1) At the dataset level, it is difficult to collect sufficient training data for minority languages such as Bangla compared to popular languages such as English and Chinese, which affects the quality of recognition models. 2) At the language level, the size of character sets varies from tens to thousands across different languages, which leads to data imbalance. 3) At the character level, the occurrence frequency of characters follows a long-tailed distribution, leading to class imbalance. In addition, IMLTR faces the problem of variable length recognition, where text instances are the recognizing unit instead of character classes. Therefore, IL methods cannot sample characters as evenly as required in the context of IMLTR, resulting in a significant fraction of characters not being included in the rehearsal data, as shown in Fig. 2. This phenomenon is summarized as rehearsal-imbalance in Fig. 1. Rehearsal-imbalance leads to catastrophic forgetting, where forgotten characters cannot be recognized. Therefore, there is an urgent need to develop new methods to overcome it." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.643, + 0.47, + 0.853 + ], + "angle": 0, + "content": "Although the rehearsal set does not ensure full coverage of all interlingual character classes, it is still adequate for training a language domain predictor to identify the languages. Motivated by this observation, we propose a novel Multiplexed Routing Network (MRN) for IMLTR. MRN involves training a new text recognition model at each learning step and utilizing it and previously trained models for parallel feature extraction. A domain MLP router is designed to receive these features and predict the probability over the languages. Meanwhile, these features are used for character recognition in their own domain by feeding them to the multi-lingual modeling module. Finally, we fuse the results obtained at both the language domain and character levels to decode the recognized character sequence." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.471, + 0.901 + ], + "angle": 0, + "content": "Our contributions can be summarized as follows. First, we introduce the IMLTR task, the first effort to adapt IL to text recognition. It contributes to the exploration of other" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.088, + 0.892, + 0.319 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.322, + 0.894, + 0.378 + ], + "angle": 0, + "content": "Figure 2. The showcase of rehearsal-imbalance. Data-imbalance (top) and class-imbalance (bottom) are severely aggravated from the full dataset to the rehearsal set, while the character classes to be read remain the same, making IMLTR particularly challenging." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.402, + 0.892, + 0.523 + ], + "angle": 0, + "content": "practical scenarios for text recognition. Second, we develop MRN to address the rehearsal-imbalance problem in ILMTR. It is a dynamic and scalable architecture that is compatible with various IL methods and recognition models. Third, experiments on two benchmarks show that MRN significantly outperforms existing general-purpose IL methods, achieving accuracy improvements ranging from \\(10.3\\%\\) to \\(27.4\\%\\) under different settings." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.536, + 0.642, + 0.551 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.561, + 0.741, + 0.577 + ], + "angle": 0, + "content": "2.1. Incremental Learning (IL)" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.584, + 0.892, + 0.901 + ], + "angle": 0, + "content": "IL has received intensive research attention over the past few years. Typically, the problem is investigated in the context of image classification, where addressing catastrophic forgetting effectively and efficiently is its core issue. We can broadly classify existing efforts into three categories: regularization [30, 50, 15], rehearsal [36, 9, 1] and dynamic expansion [2, 46, 17, 28]. Regularization methods emphasize constraining weight changes, e.g., allowing only small magnitude changes from the previous weights. It suffers from the problem that the changes do not adequately describe the complex pattern shifts caused by new task learning. Rehearsal methods keep a small amount of old data when training a new task, thus retaining some prior knowledge. Studies in this category focus on the selection of old data and the way it is used. For example, iCaRL was developed to learn an exemplar-based data representation [37]. Alternatively, dynamic expansion methods dynamically create feature extraction sub-networks each associated with one specific task [23, 12, 45, 28]. Early methods required a task identifier to select the correct sub-network at test time. Unfortunately, the assumption is unrealistic as new sam" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "18645" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.09, + 0.892, + 0.396 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.4, + 0.893, + 0.457 + ], + "angle": 0, + "content": "Figure 3. An overview of MRN. In stage-I, text recognizers are trained language-by-language. While in stage-II, these recognizers are frozen for feature extraction. The Domain MLP Router, which is trained based on the rehearsal set, is proposed to predict the likelihood distribution over the languages. Meanwhile, a padded classification layer is constructed, where the parallel predicted text sequences and likelihood distributions are merged to generate the decoded character sequence." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.48, + 0.473, + 0.661 + ], + "angle": 0, + "content": "plies would not come with their task identifiers. Recently, DER [46] proposed a dynamically expandable representation by discarding the task identifier, where the classifier was finetuned on a balanced exemplar subset to mitigate the task-tendency bias. It attained impressive results. Some recent works [7, 14] studied IL in inhomogeneous or uneven datasets. However, the datasets they adopted are still ideal and cannot sufficiently describe challenges in real-world problems. Moreover, there were also some studies proposed for object detection [21, 10, 48, 47], semantic segmentation [49, 16, 51] and object retrieval [32]. Text recognition has not been studied in IL so far." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.677, + 0.345, + 0.695 + ], + "angle": 0, + "content": "2.2. Scene Text Recognition (STR)" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.703, + 0.47, + 0.824 + ], + "angle": 0, + "content": "Text recognition is a longstanding research topic in computer vision and pattern recognition. Recent efforts mainly focused on recognizing text in natural scenes, i.e., STR. The task exhibits variations like text distortion, occlusion, blurring, etc., making the recognition challenging. With the advances in deep learning, especially CNN [5, 39, 26, 40] and Transformers [38, 20, 54, 43, 18, 44], STR methods have been pushed forward significantly." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Multilingual text recognition (MLTR) is an important sub-field of STR. The most popular solution for MLTR was data-joint training [35, 8, 34, 4], where all data was gathered to train a model capable of recognizing all character classes. However, in addition to computational inten" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.48, + 0.895, + 0.678 + ], + "angle": 0, + "content": "sive, the approach also had the drawback of being biased toward data-rich languages, while performing poorly in minority languages where training data was scarce. As alternatives, multi-task or ensemble architectures were developed to allow data-rich languages to transfer knowledge to datapoor ones [6, 13]. They alleviated the data scarcity issue to some extent. In addition, Some studies [22, 24, 41, 29] added a script identification step to text recognition. They first identified the language domain and then selected the corresponding recognizer. Although similar to ours in the pipeline, they did not explore dependencies between languages. Moreover, none of them discussed the task within the IL framework." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.697, + 0.637, + 0.715 + ], + "angle": 0, + "content": "3. Methodology" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.724, + 0.866, + 0.741 + ], + "angle": 0, + "content": "3.1. Incremental Multilingual Text Recognition" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Our goal is to develop a unified model that can recognize text instances in different languages, with the model trained incrementally language-by-language. Mathematically, assume there are \\(I\\) kinds of languages \\(\\{\\mathcal{D}_1,\\dots ,\\mathcal{D}_I\\}\\), with \\(\\mathcal{D}_i = \\left\\{(\\mathbf{x}_{i,1},y_{i,1}),\\dots ,(\\mathbf{x}_{i,N(i)},y_{i,N(i)})\\right\\}\\) as the training data at step \\(i\\) (i.e., task \\(i\\)), where \\(x_{i,j}\\) is the \\(j\\)-th input image and \\(y_{i,j} \\in \\mathcal{C}_i\\) is its label within the label set \\(\\mathcal{C}_i\\), \\(N(i)\\) is the number of samples in set \\(\\mathcal{D}_i\\). At the \\(i\\)-th learning step, samples of the \\(i\\)-th language will be added to the training set. Therefore, the goal can be formulated as to learn" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "18646" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.244 + ], + "angle": 0, + "content": "new knowledge from the set \\(\\mathcal{D}_i\\), while retaining the previous knowledge learned from old data \\(\\{\\mathcal{D}_1, \\dots, \\mathcal{D}_{i-1}\\}\\). The label space of the model is all seen categories \\(\\tilde{\\mathcal{C}}_i = \\cup_{k=1}^i \\mathcal{C}_k\\) and the model is expected to predict well on all classes in \\(\\tilde{\\mathcal{C}}_i\\). Note that there may be a small overlap between label sets, i.e., \\(\\mathcal{C}_k \\cap \\mathcal{C}_j \\neq \\emptyset\\) for some \\(k\\) and \\(j\\). To better fight against catastrophic forgetting, we discuss IMLTR in the rehearsal setting. That is, a small and fix-sized rehearsal set \\(\\mathcal{M}_i\\) with a portion of samples from \\(\\{\\mathcal{D}_1, \\dots, \\mathcal{D}_{i-1}\\}\\) is accessible at incremental step \\(i\\)." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.253, + 0.377, + 0.269 + ], + "angle": 0, + "content": "3.2. Challenge and Solution Statement" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.276, + 0.473, + 0.578 + ], + "angle": 0, + "content": "To build a recognition model to correctly recognize text instances from all currently seen languages and their character classes, let \\( x_{n} \\) be the text instance to be recognized. \\( y_{n}^{t} \\in \\tilde{\\mathcal{C}}_{i} \\) denotes the \\( t \\)-th character label corresponding to \\( x_{n} \\). \\( T(n) \\) gives the total number of characters in this instance. IMLTR differs significantly from existing IL settings. For example compared to incremental image classification, standard IL usually has \\( |\\tilde{\\mathcal{C}}_i| \\leq 100 \\) and \\( T(n) = 1 \\) regardless of the value \\( n \\). While the size of rehearsal set \\( \\mathcal{M}_i \\) is a constant (e.g., 2,000). However, in IMLTR \\( \\mathcal{C}_i \\) ranges from dozens of to thousands of character classes for different languages, and \\( T(n) \\) belongs to (1, 25), assuming 25 as the maximized length of a character sequence. Consequently, rehearsal-imbalance becomes a prominent challenge. Due to the limited size of the rehearsal set, it is not rare that a character class appears in the full dataset but is absent from the rehearsal set, as shown in Fig. 2. Thus, the incrementally trained models are likely to forget the absent character classes, despite having learned them previously, which can ultimately hurt the recognition accuracy." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.579, + 0.47, + 0.714 + ], + "angle": 0, + "content": "Although the rehearsal set may not be enough to train a multilingual text recognizer to identify thousands of character classes, it is still sufficient to train a language classifier to recognize the language domains present in the text instance, whose classes are a much smaller number. Once the language domains are identified, we can choose an alternative scheme that involves aggregating the results from corresponding language recognizers to perform the recognition task, thereby bypassing the rehearsal-imbalance issue." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.714, + 0.47, + 0.851 + ], + "angle": 0, + "content": "Motivated by this, we define \\(\\mathcal{H}_i\\) and \\(\\varphi_i\\) the skeleton network (all except classifier) and classifier trained at the \\(i\\)-th incremental step. Note that \\(\\mathcal{H}_i\\) is trained on \\(\\mathcal{D}_i\\), therefore can only recognize character classes of the \\(i\\)-th language in principle. Meanwhile, \\(\\varphi_i\\) is set to have \\(\\tilde{\\mathcal{C}}_i\\) nodes to be compatible with typical IL settings, despite not being taught to recognize character classes of other languages. Then, we can adopt an aggregating-like scheme to implement IMLTR. The learning function can be written as:" + }, + { + "type": "equation", + "bbox": [ + 0.137, + 0.861, + 0.47, + 0.905 + ], + "angle": 0, + "content": "\\[\n\\sum_ {k = 1} ^ {i} \\prod_ {t = 1} ^ {T (n)} \\left(P \\left(y _ {n} ^ {t} \\mid x _ {n}; \\mathcal {H} _ {k}, \\varphi_ {k}\\right) * S \\left(d _ {n} ^ {k}\\right)\\right), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.895, + 0.198 + ], + "angle": 0, + "content": "where \\(d_n^k\\) is the domain score indicating \\(x_{n}\\) being classified as the \\(k\\)-th language. \\(S(\\cdot)\\) is the score quantization function, which can be a one-hot vector (hard-voting) or a likelihood distribution (soft-voting). Eq. 1 treats IMLTR as a weighted ensemble of recognition models trained based on different languages. By doing so, it successfully overcomes the rehearsal-imbalance issue within the IL framework." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.208, + 0.676, + 0.223 + ], + "angle": 0, + "content": "3.3. Method Overview" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.232, + 0.895, + 0.382 + ], + "angle": 0, + "content": "We propose a Multiplexed Routing Network (MRN) to implement this idea. As illustrated by Fig. 3, it contains two stages, i.e., individual language modeling (stage-I) and multi-lingual modeling (stage-II). In stage-I, given \\(\\mathcal{D}_i\\) for the \\(i\\)-th language, we train its recognizer using a popular text recognition model, which can recognize the character classes seen in \\(\\mathcal{D}_i\\). The model is represented as \\(\\mathcal{H}_i\\) and \\(\\varphi_i\\). For character classes in \\(\\tilde{\\mathcal{C}}_i\\) but not in \\(\\mathcal{C}_i\\), we simply truncate gradient propagation from these nodes thus the learned model still focuses on recognizing the \\(i\\)-th language." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.384, + 0.895, + 0.685 + ], + "angle": 0, + "content": "Stage-II aims at building a multilingual routing network for IMLTR. Given a text instance \\( x_{n} \\in \\mathcal{D}_{i} \\cup \\mathcal{M}_{i} \\), we feed it into all the learned \\( i \\) skeleton networks in parallel, while keeping the parameters of the networks frozen for targeted feature extraction. It extracts \\( i \\) sets of features, each associated with a certain language. The features are further fed into a Domain MLP Router (DM-Router) module, which is designed for domain score estimation, i.e., estimating the likelihood that the text instance belongs to the languages. Meanwhile, the \\( i \\) sets of features are fed to their respective classifiers, where the corresponding recognition character sequences are obtained. To merge their recognition, we pad the classification nodes with zeros to \\( |\\tilde{\\mathcal{C}}_i| \\), ensuring that all classifiers are aligned to the same dimension. As a result, their recognized characters can be merged using weighted element-wise addition, where the weights are the domain scores estimated using DM-Router. Finally, the recognition is conducted by applying a CTC- or attention-based decoding. Since DM-Router plays a critical role in the proposed method, we provide a detailed illustration below." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.696, + 0.702, + 0.71 + ], + "angle": 0, + "content": "3.4. Domain MLP Router" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.894, + 0.901 + ], + "angle": 0, + "content": "DM-Router uses features that are biased towards different language domains to discriminate the language domain of text instances. It accomplishes this by leveraging both the rehearsal set and the language data that arrives at the \\(i\\)-th step. While training a separate single-network classifier, which takes an image as input and outputs the language domain scores, can identify the language domains, we believe that this approach overlooks inter-domain dependencies that could be explored for better identification. For instance, different languages may have distinct appearance patterns, such as strokes, which differ significantly between Eastern Asian languages and Latin. Additionally, their features ex" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "18647" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.08, + 0.089, + 0.473, + 0.288 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.291, + 0.47, + 0.334 + ], + "angle": 0, + "content": "Figure 4. Detail structure of Domain MLP Router (DM-Router). Spatial-domain and Channel-domain dependencies are explored and fused to generate the language domain score distribution." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.365, + 0.47, + 0.396 + ], + "angle": 0, + "content": "hibit different frequency distributions, which can also aid language identification." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.399, + 0.473, + 0.761 + ], + "angle": 0, + "content": "To achieve this goal, DM-Router accepts all \\(i\\) sets of features extracted previously as input and mines the spatial-domain and channel-domain dependencies for better language identification. The detailed structure of DM-Router is shown in Fig. 4. Features from different skeleton networks are concatenated, generating a feature cubic with size \\(P \\times D \\times C\\), where \\(P\\), \\(D\\), and \\(C\\) stand for the number of reshaped spatial patches, language domains, and feature channels, respectively. Then, a linear projection is applied along the channel dimension (C Proj), followed by reshaping the cubic from the patch-domain dimension. Next, a gated-mechanism is followed to generate the attention scores between the patch and domain. This is achieved by applying linear projection along the patch-domain dimension, followed by a layer norm and a feature dot product. We reshape the generated feature back to a feature cubic of the same size and merge it with the original cubic. The operations above explore the spatial-domain dependency. A similar operation is then applied to the merged feature cubic to explore the channel-domain dependence. In the following, the explored feature cubic gradually shrinks to a \\(D\\)-dimensional score vector that indicates the probability over the languages. It represents the likelihood of each language domain for the input text instance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.47, + 0.903 + ], + "angle": 0, + "content": "DM-Router is an MLP-based attention network that targets language domain weighting. Note that there are a few similar solutions in the literature. Expert Gate (E-Gate) [2] developed an expert gating network that identified which model could be employed based on image reconstruction loss. However, it might not effectively discriminate IMLTR due to some languages exhibiting character class overlapping, which can cause classification confusion. On the other hand, multilingual OCR [29] determines the languages by" + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.09, + 0.891, + 0.171 + ], + "angle": 0, + "content": "
DatasetcategoriesTask1Task2Task3Task4Task5Task6
ChineseLatinJapaneseKoreanArabicBangla
MLT17[35]train instance2687474114609563137113237
test instance5291107313501230983713
train class18953251620112473112
MLT19[34]train instance2897529215324610742303542
test instance3225882590679470393
train class20862201728116073102
" + }, + { + "type": "table_caption", + "bbox": [ + 0.524, + 0.18, + 0.868, + 0.193 + ], + "angle": 0, + "content": "Table 1. MLT17 and MLT19 statistics in our experiments." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.217, + 0.892, + 0.307 + ], + "angle": 0, + "content": "script recognition and selected the corresponding model for recognition. Unlike these hard-voting methods, MRN employs soft-voting, which allows for the use of knowledge from other languages. For instance, Japanese has the ability to correct Chinese to some extent, given that they share some common words and similar strokes." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.315, + 0.644, + 0.331 + ], + "angle": 0, + "content": "3.5. Training Loss" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.339, + 0.892, + 0.383 + ], + "angle": 0, + "content": "MRN has two loss terms. One for multilingual text recognition while the other for language domain prediction. The total loss function is written as:" + }, + { + "type": "equation", + "bbox": [ + 0.605, + 0.393, + 0.891, + 0.409 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\mathrm {c l f}} + \\alpha \\mathcal {L} _ {\\text {d o m a i n}}, \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.418, + 0.891, + 0.433 + ], + "angle": 0, + "content": "where \\(\\alpha\\) is an empirical hyperparameter to balance the two." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.434, + 0.892, + 0.629 + ], + "angle": 0, + "content": "MRN shows two advantages in dealing with rehearsal-imbalance. First, it ensures fair use of language. As previously mentioned, data distribution is uneven across different languages, and if not addressed during model training, it may lead to bias in the resulting model. By adopting language-by-language training and parameter freezing, data-rich and data-poor languages are treated equally, and class-imbalance is also alleviated. Second, MRN makes use of inter-lingual dependency in two ways: through the DM-Router described earlier, and through recognition score merging. When a character is recognized by more than one language, it receives confidence scores from each of them, allowing for the utilization of inter-lingual dependencies." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.642, + 0.634, + 0.659 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.667, + 0.82, + 0.683 + ], + "angle": 0, + "content": "4.1. Datasets and Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.689, + 0.892, + 0.84 + ], + "angle": 0, + "content": "ICDAR 2017 MLT (MLT17) [35] has 68,613 training instances and 16,255 validation instances, which are from 6 scripts and 9 languages: Chinese, Japanese, Korean, Bangla, Arabic, Italian, English, French, and German. The last four use Latin script. The samples are from natural scenes with challenges like blur, occlusion, and distortion. We use the validation set for test due to the unavailability of test data. Tasks are split by scripts and modeled sequentially. Special symbols are discarded at the preprocessing step as with no linguistic meaning." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.901 + ], + "angle": 0, + "content": "ICDAR 2019 MLT (MLT19) [34] has 89,177 text instances coming from 7 scripts. Since the inaccessibility of test set, we randomly split the training instances to 9:1 script-by-script, for model training and test. To be consistent with" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "18648" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.102, + 0.088, + 0.869, + 0.484 + ], + "angle": 0, + "content": "
MLT17MLT19
Model: CRNN (TPAMI'17) [39]
T1T2T3T4T5T6AVGT1T2T3T4T5T6AVG
Bound------92.1------84.9
Baseline91.151.751.037.229.322.347.185.149.646.535.527.620.744.2
LwF (TPAMI'17)[31]91.153.753.438.229.723.748.385.151.649.236.527.722.045.3
EWC (PNAS'17)[30]91.156.550.437.230.521.547.985.155.546.335.828.819.945.2
WA (CVPR'20) [52]91.154.648.738.228.523.147.485.152.244.336.726.821.644.4
DER (CVPR'21)[46]91.176.355.846.439.335.857.585.175.240.445.136.634.252.8
MRN91.188.677.273.769.869.878.485.185.173.268.365.365.573.7
Model: TRBA (ICCV'19) [3]
T1T2T3T4T5T6AVGT1T2T3T4T5T6AVG
Bound------94.9------90.5
Baseline91.349.647.336.128.624.046.185.449.444.034.827.423.144.0
LwF (TPAMI'17)[31]91.355.738.828.722.618.742.685.454.235.027.220.517.039.9
EWC (PNAS'17)[30]91.350.443.633.125.621.944.385.449.440.631.724.820.642.1
WA (CVPR'20) [52]91.345.441.830.723.519.642.185.444.037.929.221.618.139.4
DER (CVPR'21)[46]91.360.153.038.831.428.650.585.460.750.337.230.328.148.7
MRN91.387.975.872.271.568.777.985.484.573.267.866.764.873.7
Model: SVTR-Base (IJCAI'22) [18]
T1T2T3T4T5T6AVGT1T2T3T4T5T6AVG
Bound------90.1------83.2
Baseline90.632.540.530.824.519.939.884.831.337.029.222.619.137.3
LwF (TPAMI'17)[31]90.628.038.429.924.118.338.284.827.034.628.422.317.035.7
EWC (PNAS'17)[30]90.633.041.231.124.620.040.184.831.337.729.522.619.037.5
WA (CVPR'20) [52]90.628.037.930.424.819.838.684.826.734.628.322.618.635.9
DER (CVPR'21)[46]90.674.555.755.049.545.761.884.871.652.952.246.643.658.6
MRN90.686.473.965.663.458.173.084.883.769.464.457.853.168.9
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.495, + 0.892, + 0.525 + ], + "angle": 0, + "content": "Table 2. Accuracy (%) of different text recognizers and incremental learning methods on MLT17 and MLT19. Baseline denotes the model trained solely based on the rehearsal set and language data arrived at that step. The language incremental order is introduced in Sec. 4.1." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.548, + 0.469, + 0.578 + ], + "angle": 0, + "content": "MLT2017 dataset, we discard the Hindi script and also special symbols. Statistics of the two datasets are shown Tab. 1." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.579, + 0.47, + 0.79 + ], + "angle": 0, + "content": "Height and width of the images are scaled uniformly to \\(32 \\times 256\\). The maximum length of a character sequence is set to 25. All models, each corresponding to a language domain, are trained with 10,000 iterations, using the Adam optimizer and the one-cycle learning rate scheduler [42] with a maximum learning rate of 0.0005. The batch size is set to 256. To mitigate the dataset variance, in each batch we evenly sample training samples from both datasets, that is, half from MLT17 and half from MLT19. A random order for the six languages is employed, which is Chinese, Latin, Japanese, Korean, Arabic, Bangla. Other orders will be discussed later. For the rehearsal setting, we limit the rehearsal size to 2000 samples unless specified. We conduct the experiments using two NVIDIA RTX 3090 GPUs." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.802, + 0.387, + 0.818 + ], + "angle": 0, + "content": "4.2. Comparison with Existing Methods" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.826, + 0.471, + 0.901 + ], + "angle": 0, + "content": "We equip MRN with different text recognizers and combine them with different IL methods. Specifically, we consider three typical STR schemes: CTC-based (CRNN [39]), attention-based (TRBA [3]), and ViT-based (SVTR [18]). Meanwhile, four popular IL methods are chosen, i.e., Lwf" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.548, + 0.892, + 0.594 + ], + "angle": 0, + "content": "[31], EWC [30], WA [52] and DER [46]. All models retain their original settings, except for the removal of the auxiliary loss of DER, which reduces its performance in our task." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.599, + 0.893, + 0.901 + ], + "angle": 0, + "content": "In Tab. 2, we give the results at different incremental steps, where the language is added one-by-one and the average accuracy of different methods is reported. Bound, the model trained using all training data, is also listed as the oracle for reference. As can be seen, MRN consistently outperforms all the compared methods by significant margins under different settings, no matter which recognizer is employed. When looking into the general-purpose IL methods, their accuracy mostly decreased rapidly as the incremental steps due to the affection of rehearsal-imbalance. DER has the highest accuracy among them, as its dynamic expansion architecture has certain advantages in fighting against catastrophic forgetting. However, there is still a clear accuracy gap between DER and our MRN, and the gap widens as the incremental step increases. We attribute the accuracy improvement achieved by MRN to two factors. First, IMLTR is a task that differs significantly from image classification, where most IL methods have been experimented on. These methods do not well accommodate the challenge raised by IMLTR. For example, the rehearsal-imbalance issue. Sec-" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.52, + 0.957 + ], + "angle": 0, + "content": "18649" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.091, + 0.47, + 0.152 + ], + "angle": 0, + "content": "ond, MRN develops an elegant pipeline that implements the recognition in a domain routing and result fusion manner. It works particularly well for scenarios where incremental tasks exhibit significant differences." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.152, + 0.471, + 0.289 + ], + "angle": 0, + "content": "When comparing the recognizers, MRN equipped with CRNN has the highest overall accuracy. The result is interesting as CRNN has a simpler architecture and generally performs worse than the other two methods on typical STR tasks. We attribute this to parameter freezing, where the feature extraction backbone (e.g., \\(\\mathcal{H}_i\\)) and the decoder cannot be jointly optimized. Therefore, advanced models are more severely affected, while the simpler one is less affected and can better mitigate catastrophic forgetting." + }, + { + "type": "table", + "bbox": [ + 0.117, + 0.298, + 0.432, + 0.424 + ], + "angle": 0, + "content": "
modelMLT17MLT19
AvgLastAvgLast
None64.837.960.835.6
MLP68.560.565.356.3
CycleMLP[11]75.563.571.160.0
ViP[25]76.462.672.259.6
gMLP[33]77.568.273.164.2
DM-Router78.469.873.865.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.434, + 0.445, + 0.448 + ], + "angle": 0, + "content": "Table 3. Performance comparisons on different MLP models." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.47, + 0.231, + 0.487 + ], + "angle": 0, + "content": "4.3. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.494, + 0.47, + 0.539 + ], + "angle": 0, + "content": "We perform a series of controlled experiments to gain a deeper understanding of MRN. CRNN is employed as the text recognizer unless specified." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.539, + 0.471, + 0.735 + ], + "angle": 0, + "content": "Effectiveness of DM-Router: There are multiple ways to deduce the language domain scores. We enumerate several of them that have been used in existing studies, as shown in Tab. 3. None denotes no dependence is explored, which corresponds to the worst result. It, in turn, demonstrates the necessity of utilizing language dependence. Among the rest competitors, MLP enables a naive learning mechanism while the remaining three are based on more advanced MLP-like models, which are typically more effective. Despite this, DM-Router attains the highest accuracy among the methods. The results clearly demonstrate the rationality of the DM-Router structure in terms of language dependence exploration." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Influence of the size of the rehearsal set: We conduct analytical experiments to evaluate the influence of the rehearsal size on the accuracy of Lwf [31], DER [46] and MRN. Fig. 4 shows the accuracy under different rehearsal sizes. As anticipated, increasing the rehearsal set size leads to accuracy gains, as more past memories are retained. We observe that larger gains are obtained in LwF and DER, particularly DER. This reveals the accuracy of general-purpose IL methods is largely affected by the rehearsal size in IMLTR, while MRN is less affected. MRN has already achieved relatively high accuracy, and the performance of MRN in iden" + }, + { + "type": "table", + "bbox": [ + 0.544, + 0.089, + 0.855, + 0.253 + ], + "angle": 0, + "content": "
SizeMethodMLT17MLT19
AvgLastAvgLast
2kLwF[31]48.323.745.422.0
DER[46]57.535.852.834.2
MRN78.469.873.865.5
3kLwF[31]52.224.948.823.6
DER[46]60.942.058.740.6
MRN80.272.775.468.2
4kLwF[31]55.527.552.226.1
DER[46]66.448.763.846.6
MRN81.575.076.570.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.533, + 0.263, + 0.859, + 0.277 + ], + "angle": 0, + "content": "Table 4. Ablation study on the size of the rehearsal set." + }, + { + "type": "table", + "bbox": [ + 0.53, + 0.289, + 0.863, + 0.462 + ], + "angle": 0, + "content": "
OrderMethodMLT17MLT19
AvgLastAvgLast
O1LwF[31]48.323.745.422.0
DER[46]57.535.852.834.2
MRN78.469.873.865.5
O2LwF[31]46.923.843.122.9
DER[46]63.139.158.739.6
MRN80.565.374.161.5
O3LwF[31]57.734.755.734.2
DER[46]69.641.365.738.2
MRN82.970.678.366.0
" + }, + { + "type": "table_caption", + "bbox": [ + 0.569, + 0.471, + 0.824, + 0.486 + ], + "angle": 0, + "content": "Table 5. Ablation study on language order." + }, + { + "type": "table", + "bbox": [ + 0.529, + 0.498, + 0.865, + 0.595 + ], + "angle": 0, + "content": "
Sampling StrategyMLT17MLT19
AvgLastAvgLast
Confidence56.443.854.041.2
Length71.050.366.648.9
Frequency72.656.667.853.7
Random78.469.873.865.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.532, + 0.604, + 0.86, + 0.619 + ], + "angle": 0, + "content": "Table 6. Ablation study on rehearsal sampling strategy." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.643, + 0.892, + 0.688 + ], + "angle": 0, + "content": "tifying language domains is less affected by the rehearsal size. The results indicate that MRN is robust to rehearsal scarcity and can better fight against data imbalance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.689, + 0.892, + 0.809 + ], + "angle": 0, + "content": "Influence of language incremental order: In addition to the order in Sec. 4.1 (O1), we assess two other orders as follows: 1) Arabic, Chinese, Latin, Japanese, Bangla, Korean (O2); 2) Latin, Arabic, Bangla, Chinese, Japanese, Korean (O3). The two orders either alternate the three Eastern Asia languages, which have large vocabularies and show more stroke commonalities, or group them together at the end. We also include Lwf and DER for comparison." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Tab. 5 gives the results and two observations. First, O3 shows the best accuracy, while O2 also performs better than O1. It is because the three Eastern Asia languages are more difficult to recognize due to their large vocabulary sizes, therefore introducing them later leads to a better average accuracy. Meanwhile, putting them together also reduces the" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "18650" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.164, + 0.089, + 0.813, + 0.203 + ], + "angle": 0, + "content": "
MethodSelectModelVotingMLT17MLT19Params (M)FLOPs (G)
AvgLastAvgLast
Baseline---47.122.344.220.79.53.5
DER[46]---57.535.852.834.233.812.3
E-Gate[2]Re-Const.AutoencoderHard37.215.234.814.232.512.2
E-Gate[2]StackingAutoencoderHard62.715.259.314.235.512.4
MRNStackingDM-RouterHard74.462.969.957.733.512.4
MRNStackingDM-RouterSoft78.469.873.865.533.512.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.328, + 0.212, + 0.642, + 0.227 + ], + "angle": 0, + "content": "Table 7. Comparisons on different routing strategies." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.251, + 0.47, + 0.386 + ], + "angle": 0, + "content": "oscillation during parameter learning and generates a better model, due to their stroke commonalities. The experiment suggests that careful selection of the order of languages can attain better accuracy. Second, O1 shows the largest accuracy gaps between MRN and other methods. This is because in O1, the large vocabulary languages appear earlier, while the rehearsal set is fix-sized, resulting in the most severe class imbalance among the three orders. The result indicates that MRN can better handle class imbalance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.387, + 0.471, + 0.643 + ], + "angle": 0, + "content": "Influence of rehearsal sampling strategy: The determination of text instances being sampled to the rehearsal set is an issue also worthy of abulating. Tab. 6 gives the accuracy of four sampling strategies, i.e., Confidence that selects instances with the highest recognition scores, Length that selects instances with the largest number of characters, Frequency that selects instances with the most frequently occurred characters, and Random adopted in our MRN that randomly selects the instances. Interestingly, Random gives the best accuracy. We attribute the reason to: the rehearsal set obtained from Confidence or Frequency cannot fully represent the true data distribution, where difficult or less occurred instances are excluded. Length, to some extent, overlooks the varying-length characteristic of IMLTR. On the contrary, Random, despite simple, well mimics the underlying data distribution and well handles the variable length challenge." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.644, + 0.471, + 0.812 + ], + "angle": 0, + "content": "Comparison on routing strategy: We compare MRN with E-Gate and its variants. E-Gate [2] treats different subnetworks as experts, and each time selects the most appropriate one for inference. In Tab. 7 we provide the model details. Raw E-Gate performs poorly in IMLTR. When stacking is used to build feature extractors, the accuracy improves significantly and outperforms DER. We also evaluate MRN with hard-voting. It reports a worse result. Compared to other routing strategies, our MRN shows clear superiority in terms of accuracy, while incurring only a negligible cost in parameters and computational complexity." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.818, + 0.33, + 0.833 + ], + "angle": 0, + "content": "4.4. Qualitative Results Analysis" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Fig. 5 gives several recognition results of MRN. It correctly read instances of different languages, even with the presence of common recognition difficulties. More importantly, MRN also recognizes character classes that are not" + }, + { + "type": "image", + "bbox": [ + 0.515, + 0.251, + 0.88, + 0.445 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.448, + 0.892, + 0.474 + ], + "angle": 0, + "content": "Figure 5. Illustrative recognition examples, where red denotes characters that are absent from the rehearsal set." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.5, + 0.892, + 0.545 + ], + "angle": 0, + "content": "present in the rehearsal set. These results again demonstrate that our MRN is effective in handling rehearsal-imbalance and can generalize well to unseen character classes." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.561, + 0.62, + 0.577 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.588, + 0.892, + 0.83 + ], + "angle": 0, + "content": "In this work, we introduce a new task called incremental multilingual text recognition (IMLTR). IMLTR handles text recognition in an incremental learning setting, therefore is suitable for applications like streaming data processing. IMLTR faces a distinct problem of rehearsal-imbalance, including data imbalance, class imbalance, and variable character length. To address this challenge, we designed a Multiplexed Routing Network (MRN) that first trains a multi-language correlated DM-router to weight the language domains, and then votes the separately trained recognition branches for final text recognition. Experiments on public benchmarks show that MRN significantly outperforms existing general-purpose IL methods by large margins. As the first attempt to apply IL to multilingual text recognition, we hope that this work will broaden the applications of text recognition and inspire further research in this area." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.84, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Acknowledgments This project was supported by National Key R&D Program of China (No. 2022YFB3104703) and in part by the National Natural Science Foundation of China (No. 62172103)" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.518, + 0.957 + ], + "angle": 0, + "content": "18651" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.47, + 0.17 + ], + "angle": 0, + "content": "[1] Rahaf Aljundi, Francesca Babiloni, Mohamed Elhoseiny, Marcus Rohrbach, and Tinne Tuytelaars. Memory aware synapses: Learning what (not) to forget. In ECCV, pages 139-154, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.173, + 0.47, + 0.214 + ], + "angle": 0, + "content": "[2] Rahaf Aljundi, Punarjay Chakravarty, and Tinne Tuytelaars. Expert gate: Lifelong learning with a network of experts. In CVPR, July 2017. 2, 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.217, + 0.47, + 0.285 + ], + "angle": 0, + "content": "[3] Jeonghun Baek, Geewook Kim, Junyeop Lee, Sungrae Park, Dongyoon Han, Sangdoo Yun, Seong Joon Oh, and Hwalsuk Lee. What is wrong with scene text recognition model comparisons? dataset and model analysis. In ICCV, pages 4714-4722, 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.288, + 0.47, + 0.343 + ], + "angle": 0, + "content": "[4] Youngmin Baek, Seung Shin, Jeonghun Baek, Sungrae Park, Junyeop Lee, Daehyun Nam, and Hwalsuk Lee. Character region attention for text spotting. In ECCV, pages 504-521. Springer, 2020. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.345, + 0.47, + 0.413 + ], + "angle": 0, + "content": "[5] Jinfeng Bai, Zhineng Chen, Bailan Feng, and Bo Xu. Chinese image text recognition on grayscale pixels. In 2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), pages 1380-1384. IEEE, 2014. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.416, + 0.47, + 0.485 + ], + "angle": 0, + "content": "[6] Jinfeng Bai, Zhineng Chen, Bailan Feng, and Bo Xu. Image character recognition using deep convolutional neural network learned from different languages. In 2014 IEEE International Conference on Image Processing (ICIP), pages 2560-2564. IEEE, 2014. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.487, + 0.469, + 0.527 + ], + "angle": 0, + "content": "[7] Eden Belouadah and Adrian Popescu. II2m: Class incremental learning with dual memory. In ICCV, pages 583-592, 2019. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.53, + 0.469, + 0.572 + ], + "angle": 0, + "content": "[8] Michal Bušta, Yash Patel, and Jiri Matas. E2e-plt-an unconstrained end-to-end method for multi-language scene text. In ACCV, pages 127–143. Springer, 2018. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.574, + 0.469, + 0.615 + ], + "angle": 0, + "content": "[9] Francisco M Castro, Manuel J Marín-Jiménez, Nicolás Guil, Cordelia Schmid, and Karteek Alahari. End-to-end incremental learning. In ECCV, pages 233-248, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.617, + 0.469, + 0.657 + ], + "angle": 0, + "content": "[10] Li Chen, Chunyan Yu, and Lvcai Chen. A new knowledge distillation for incremental object detection. In IJCNN, pages 1-7. IEEE, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.66, + 0.469, + 0.702 + ], + "angle": 0, + "content": "[11] Shoufa Chen, Enze Xie, Chongjian GE, Runjian Chen, Ding Liang, and Ping Luo. CycleMLP: A MLP-like architecture for dense prediction. In ICLR, 2022. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.704, + 0.469, + 0.745 + ], + "angle": 0, + "content": "[12] Mark Collier, Efi Kokiopoulou, Andrea Gesmundo, and Jesse Berent. Routing networks with co-training for continual learning. ICML, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.748, + 0.469, + 0.816 + ], + "angle": 0, + "content": "[13] Jia Cui, Brian Kingsbury, Bhuvana Ramabhadran, George Saon, Tom Sercu, Kartik Audhkhasi, Abhinav Sethy, Markus Nussbaum-Thom, and Andrew Rosenberg. Knowledge distillation across ensembles of multilingual models for low-resource languages. In ICASSP, pages 4825-4829, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.469, + 0.899 + ], + "angle": 0, + "content": "[14] Matthias De Lange, Rahaf Aljundi, Marc Masana, Sarah Parisot, Xu Jia, Aleš Leonardis, Gregory Slabaugh, and Tinne Tuytelaars. A continual learning survey: Defying forgetting in classification tasks. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(7):3366-3385, 2022. 1, 2, 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.47, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.135 + ], + "angle": 0, + "content": "[15] Prithviraj Dhar, Rajat Vikram Singh, Kuan-Chuan Peng, Ziyan Wu, and Rama Chellappa. Learning without memorizing. In CVPR, pages 5138-5146, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.137, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[16] Arthur Douillard, Yifu Chen, Arnaud Dapogny, and Matthieu Cord. Plop: Learning without forgetting for continual semantic segmentation. In CVPR, pages 4040-4050, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.195, + 0.892, + 0.248 + ], + "angle": 0, + "content": "[17] Arthur Douillard, Alexandre Ramé, Guillaume Couairon, and Matthieu Cord. Dytox: Transformers for continual learning with dynamic token expansion. In CVPR, pages 9285–9295, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.253, + 0.892, + 0.307 + ], + "angle": 0, + "content": "[18] Yongkun Du, Zhineng Chen, Caiyan Jia, Xiaoting Yin, Tianlun Zheng, Chenxia Li, Yuning Du, and Yu-Gang Jiang. SVTR: scene text recognition with a single visual model. In IJCAI, 2022. 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.311, + 0.892, + 0.38 + ], + "angle": 0, + "content": "[19] Shancheng Fang, Zhendong Mao, Hongtao Xie, Yuxin Wang, Chenggang Yan, and Yongdong Zhang. Abinet++: Autonomous, bidirectional and iterative language modeling for scene text spotting. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.383, + 0.892, + 0.438 + ], + "angle": 0, + "content": "[20] Shancheng Fang, Hongtao Xie, Yuxin Wang, Zhendong Mao, and Yongdong Zhang. Read like humans: Autonomous, bidirectional and iterative language modeling for scene text recognition. In CVPR, pages 7094-7103, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.441, + 0.892, + 0.493 + ], + "angle": 0, + "content": "[21] Tao Feng, Mang Wang, and Hangjie Yuan. Overcoming catastrophic forgetting in incremental object detection via elastic response distillation. In CVPR, pages 9427-9436, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.498, + 0.892, + 0.552 + ], + "angle": 0, + "content": "[22] Yasuhisa Fujii, Karel Driesen, Jonathan Baccash, Ash Hurst, and Ashok C Popat. Sequence-to-label script identification for multilingualOCR. In ICDAR, volume 1, pages 161-168. IEEE, 2017. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.556, + 0.892, + 0.584 + ], + "angle": 0, + "content": "[23] Siavash Golkar, Michael Kagan, and Kyunghyun Cho. Continual learning via neural pruning. NIPS, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.586, + 0.892, + 0.641 + ], + "angle": 0, + "content": "[24] Lluis Gomez, Anguelos Nicolaou, and Dimosthenis Karatzas. Improving patch-based scene text script identification with ensembles of conjoined networks. Pattern Recognition, 67:85-96, 2017. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.644, + 0.892, + 0.711 + ], + "angle": 0, + "content": "[25] Qibin Hou, Zihang Jiang, Li Yuan, Ming-Ming Cheng, Shuicheng Yan, and Jiashi Feng. Vision permutator: A permutable mlp-like architecture for visual recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.716, + 0.892, + 0.77 + ], + "angle": 0, + "content": "[26] Wenyang Hu, Xiaocong Cai, Jun Hou, Shuai Yi, and Zhiping Lin. Gtc: Guided training of ctc towards efficient and accurate scene text recognition. In AAAI, volume 34, pages 11005-11012, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.774, + 0.892, + 0.842 + ], + "angle": 0, + "content": "[27] Xinting Hu, Kaihua Tang, Chunyan Miao, Xian-Sheng Hua, and Hanwang Zhang. Distilling causal effect of data in class incremental learning. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3957-3966, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.846, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[28] Bingchen Huang, Zhineng Chen, Peng Zhou, Jiayin Chen, and Zuxuan Wu. Resolving task confusion in dynamic expansion architectures for class incremental learning. In AAAI, volume 37, pages 908-916, 2023. 1, 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "18652" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[29] Jing Huang, Guan Pang, Rama Kovvuri, Mandy Toh, Kevin J Liang, Praveen Krishnan, Xi Yin, and Tal Hassner. A multiplexed network for end-to-end, multilingualOCR. In CVPR, pages 4547-4557, 2021. 1, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.149, + 0.47, + 0.232 + ], + "angle": 0, + "content": "[30] James Kirkpatrick, Razvan Pascanu, Neil Rabinowitz, Joel Veness, Guillaume Desjardins, Andrei A Rusu, Kieran Milan, John Quan, Tiago Ramalho, Agnieszka Grabska-Barwinska, et al. Overcoming catastrophic forgetting in neural networks. Proceedings of the national academy of sciences, 114(13):3521-3526, 2017. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.234, + 0.469, + 0.275 + ], + "angle": 0, + "content": "[31] Zhizhong Li and Derek Hoiem. Learning without forgetting. IEEE transactions on pattern analysis and machine intelligence, 40(12):2935-2947, 2017. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.277, + 0.469, + 0.332 + ], + "angle": 0, + "content": "[32] An-An Liu, Haochun Lu, Heyu Zhou, Tianbao Li, and Mohan Kankanhalli. Balanced class-incremental 3d object classification and retrieval. IEEE Transactions on Knowledge and Data Engineering, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.334, + 0.468, + 0.362 + ], + "angle": 0, + "content": "[33] Hanxiao Liu, Zihang Dai, David So, and Quoc V Le. Pay attention to mlps. NIPS, 34:9204-9215, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.363, + 0.469, + 0.445 + ], + "angle": 0, + "content": "[34] Nibal Nayef, Yash Patel, Michal Busta, Pinaki Nath Chowdhury, Dimosthenis Karatzas, Wafa Khlif, Jiri Matas, Umapada Pal, Jean-Christophe Burie, Cheng-lin Liu, et al. Icdar2019 robust reading challenge on multi-lingual scene text detection and recognition—rrc-plt-2019. In ICDAR, pages 1582–1587. IEEE, 2019. 1, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.447, + 0.469, + 0.53 + ], + "angle": 0, + "content": "[35] Nibal Nayef, Fei Yin, Imen Bizid, Hyunsoo Choi, Yuan Feng, Dimosthenis Karatzas, Zhenbo Luo, Umapada Pal, Christophe Rigaud, Joseph Chazalon, et al. Icdar2017 robust reading challenge on multi-lingual scene text detection and script identification-rrc-plt. In ICDAR, volume 1, pages 1454-1459. IEEE, 2017. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.532, + 0.469, + 0.587 + ], + "angle": 0, + "content": "[36] German I Parisi, Ronald Kemker, Jose L Part, Christopher Kanan, and Stefan Wermter. Continual lifelong learning with neural networks: A review. Neural Networks, 113:54-71, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.589, + 0.469, + 0.643 + ], + "angle": 0, + "content": "[37] Sylvestre-Alvise Rebuffi, Alexander Kolesnikov, Georg Sperl, and Christoph H Lampert. icarl: Incremental classifier and representation learning. In CVPR, pages 2001–2010, 2017. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.645, + 0.469, + 0.687 + ], + "angle": 0, + "content": "[38] Fenfen Sheng, Zhineng Chen, and Bo Xu. Ntrr: A no-recurrence sequence-to-sequence model for scene text recognition. In ICDAR, pages 781-786, 2019. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.689, + 0.469, + 0.757 + ], + "angle": 0, + "content": "[39] Baoguang Shi, Xiang Bai, and Cong Yao. An end-to-end trainable neural network for image-based sequence recognition and its application to scene text recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 39(11):2298-2304, 2017. 1, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.759, + 0.469, + 0.828 + ], + "angle": 0, + "content": "[40] Baoguang Shi, Mingkun Yang, Xinggang Wang, Pengyuan Lyu, Cong Yao, and Xiang Bai. Aster: An attentional scene text recognizer with flexible rectification. IEEE Transactions on Pattern Analysis and Machine Intelligence, 41(9):2035-2048, 2018. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.83, + 0.469, + 0.871 + ], + "angle": 0, + "content": "[41] Baoguang Shi, Cong Yao, Chengquan Zhang, Xiaowei Guo, Feiyue Huang, and Xiang Bai. Automatic script identification in the wild. In ICDAR, pages 531-535. IEEE, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.469, + 0.902 + ], + "angle": 0, + "content": "[42] Leslie N Smith and Nicholay Topin. Super-convergence: Very fast training of neural networks using large learning" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "rates. In Artificial intelligence and machine learning for multi-domain operations applications, volume 11006, pages 369-386. SPIE, 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.136, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[43] Yuxin Wang, Hongtao Xie, Shancheng Fang, Jing Wang, Shenggao Zhu, and Yongdong Zhang. From two to one: A new scene text recognizer with visual language modeling network. In ICCV, pages 14174-14183, 2021. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.192, + 0.892, + 0.261 + ], + "angle": 0, + "content": "[44] Yuxin Wang, Hongtao Xie, Shancheng Fang, Mengting Xing, Jing Wang, Shenggao Zhu, and Yongdong Zhang. Petr: Rethinking the capability of transformer-based language model in scene text recognition. IEEE Transactions on Image Processing, 31:5585-5598, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.262, + 0.892, + 0.303 + ], + "angle": 0, + "content": "[45] Yeming Wen, Dustin Tran, and Jimmy Ba. Batchsemble: an alternative approach to efficient ensemble and lifelong learning. In ICLR, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.305, + 0.892, + 0.347 + ], + "angle": 0, + "content": "[46] Shipeng Yan, Jiangwei Xie, and Xuming He. Der: Dynamically expandable representation for class incremental learning. In CVPR, pages 3014-3023, 2021. 1, 2, 3, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.349, + 0.892, + 0.417 + ], + "angle": 0, + "content": "[47] Dongbao Yang, Yu Zhou, Xiaopeng Hong, Aoting Zhang, and Weiping Wang. One-shot replay: Boosting incremental object detection via retrospecting one object. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 37, pages 3127-3135, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.419, + 0.892, + 0.473 + ], + "angle": 0, + "content": "[48] Dongbao Yang, Yu Zhou, Aoting Zhang, Xurui Sun, Dayan Wu, Weiping Wang, and Qixiang Ye. Multi-view correlation distillation for incremental object detection. Pattern Recognition, 131:108863, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.475, + 0.892, + 0.544 + ], + "angle": 0, + "content": "[49] Guanglei Yang, Enrico Fini, Dan Xu, Paolo Rota, Mingli Ding, Moin Nabi, Xavier Alameda-Pineda, and Elisa Ricci. Uncertainty-aware contrastive distillation for incremental semantic segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.546, + 0.892, + 0.586 + ], + "angle": 0, + "content": "[50] Friedemann Zenke, Ben Poole, and Surya Ganguli. Continual learning through synaptic intelligence. In ICML, pages 3987-3995. PMLR, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.588, + 0.892, + 0.643 + ], + "angle": 0, + "content": "[51] Chang-Bin Zhang, Jia-Wen Xiao, Xialei Liu, Ying-Cong Chen, and Ming-Ming Cheng. Representation compensation networks for continual semantic segmentation. In CVPR, pages 7053-7064, 2022. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.645, + 0.892, + 0.699 + ], + "angle": 0, + "content": "[52] Bowen Zhao, Xi Xiao, Guojun Gan, Bin Zhang, and Shu-Tao Xia. Maintaining discrimination and fairness in class incremental learning. In CVPR, pages 13208-13217, 2020. 1, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.701, + 0.892, + 0.743 + ], + "angle": 0, + "content": "[53] Tianlun Zheng, Zhineng Chen, Jinfeng Bai, Hongtao Xie, and Yu-Gang Jiang. Tps++: Attention-enhanced thin-plate spline for scene text recognition. *IJCAI*, 2023. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.744, + 0.892, + 0.799 + ], + "angle": 0, + "content": "[54] Tianlun Zheng, Zhineng Chen, Shancheng Fang, Hongtao Xie, and Yu-Gang Jiang. Cdistnet: Perceiving multi-domain character distance for robust text recognition. arXiv preprint arXiv:2111.11011, 2021. 3" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.799 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.957 + ], + "angle": 0, + "content": "18653" + } + ] +] \ No newline at end of file diff --git a/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/6ed06787-7eb3-4534-9eb1-83af9b81cded_origin.pdf b/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/6ed06787-7eb3-4534-9eb1-83af9b81cded_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..92eb02bda0f8113fc325506fdee47217648ce3aa --- /dev/null +++ b/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/6ed06787-7eb3-4534-9eb1-83af9b81cded_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:ee85e3b9cbe16c61848c41ea44c28d9117922eacbb8b7d2f76e6f61b0c3ff96b +size 2750369 diff --git a/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/full.md b/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/full.md new file mode 100644 index 0000000000000000000000000000000000000000..0b4954324e741d412f93aadd74f212c155da3ca7 --- /dev/null +++ b/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/full.md @@ -0,0 +1,260 @@ +# MRN: Multiplexed Routing Network for Incremental Multilingual Text Recognition + +Tianlun Zheng $^{1,2}$ , Zhineng Chen $^{1,2*}$ , Bingchen Huang $^{1,2}$ , Wei Zhang $^{3}$ and Yu-Gang Jiang $^{1,2}$ \ + $^{1}$ School of Computer Science, Fudan University, China\ + $^{2}$ Shanghai Collaborative Innovation Center of Intelligent Visual Computing, China\ + $^{3}$ Gaoding AI, China + +{t1zheng21, bchuang21}@m.fudan.edu.cn, {zhinchen, ygj}@fudan.edu.cn, wzhang.cu@gmail.com + +# Abstract + +Multilingual text recognition (MLTR) systems typically focus on a fixed set of languages, which makes it difficult to handle newly added languages or adapt to ever-changing data distribution. In this paper, we propose the Incremental MLTR (IMLTR) task in the context of incremental learning (IL), where different languages are introduced in batches. IMLTR is particularly challenging due to rehearsal-imbalance, which refers to the uneven distribution of sample characters in the rehearsal set, used to retain a small amount of old data as past memories. To address this issue, we propose a Multiplexed Routing Network (MRN). MRN trains a recognizer for each language that is currently seen. Subsequently, a language domain predictor is learned based on the rehearsal set to weigh the recognizers. Since the recognizers are derived from the original data, MRN effectively reduces the reliance on older data and better fights against catastrophic forgetting, the core issue in IL. We extensively evaluate MRN on MLT17 and MLT19 datasets. It outperforms existing general-purpose IL methods by large margins, with average accuracy improvements ranging from $10.3\%$ to $35.8\%$ under different settings. Code is available at https://github.com/simplify23/MRN. + +# 1. Introduction + +Scene text recognition (STR) is a task aiming to read text in natural scenes. Recent advances in deep learning have significantly improved the accuracy of STR, allowing it to recognize text in the presence of font variations, distortions, and noise interference [39, 40, 43, 38, 19, 53]. As countries and cultures are more interconnected, the task of simultaneously recognizing multiple languages, i.e., multilingual text recognition (MLTR), has also become more important. + +![](images/0c5aa2c85122bfbba53b92a9d91ec6ed250dfb11f4d40034fa9312614dd0c45d.jpg) +Figure 1. Incremental multilingual text recognition (IMLTR) focuses on the practical scenario where different languages are introduced sequentially. The goal is to accurately recognize the newly introduced language while maintaining high recognition accuracy for previously seen languages. IMLTR introduces a task focusing on text recognition that faces rehearsal-imbalance challenges. + +Existing methods typically address this challenge by training on mixed multilingual data [8, 4, 34] or designing independent language blocks [29, 22, 24]. However, when each time a new language is added, the above methods need retraining on a dataset mixing the old and new languages. This increases the training cost [37, 46] and also may lead to an imbalance [7, 14] between old and new data. + +Incremental learning (IL) is designed for scenarios where new data is continuously learned and typically, the old samples are maintained by a small ratio. The collection of old samples is referred to as the rehearsal set [51, 27], which serves as limited past memories. IL aims to learn the new data well while minimizing forgetting the past learned knowledge. Most existing studies [37, 7, 52, 28] conduct experiments on balanced datasets and maintain a constant number of classes at each learning step. However, in real-world scenarios, the number of classes and samples may differ across steps, leading to imbalanced datasets. To ad + +dress these issues, IL2M [7] alleviated class-imbalance by storing statistics of old classes rather than samples. Delange et al. De Lange et al. [14] surveyed typical IL methods on datasets and solutions with different data imbalances. Despite progress made, research on data and class imbalance is still in its infancy stage. Moreover, as illustrated in Fig. 1, there is currently no research introducing IL to STR. + +We rewrite MLTR in the context of IL. Languages are treated as tasks and characters are their classes. During training, the model only observes the newly arrived language data and a small amount of data from old languages. The recognition model is expected to maintain the ability to recognize characters of all languages that it has encountered before, regardless of whether their data are still available or discarded. We term this problem incremental multilingual text recognition (IMLTR). + +IMLTR poses significant challenges to IL approaches due to its unbalanced features. 1) At the dataset level, it is difficult to collect sufficient training data for minority languages such as Bangla compared to popular languages such as English and Chinese, which affects the quality of recognition models. 2) At the language level, the size of character sets varies from tens to thousands across different languages, which leads to data imbalance. 3) At the character level, the occurrence frequency of characters follows a long-tailed distribution, leading to class imbalance. In addition, IMLTR faces the problem of variable length recognition, where text instances are the recognizing unit instead of character classes. Therefore, IL methods cannot sample characters as evenly as required in the context of IMLTR, resulting in a significant fraction of characters not being included in the rehearsal data, as shown in Fig. 2. This phenomenon is summarized as rehearsal-imbalance in Fig. 1. Rehearsal-imbalance leads to catastrophic forgetting, where forgotten characters cannot be recognized. Therefore, there is an urgent need to develop new methods to overcome it. + +Although the rehearsal set does not ensure full coverage of all interlingual character classes, it is still adequate for training a language domain predictor to identify the languages. Motivated by this observation, we propose a novel Multiplexed Routing Network (MRN) for IMLTR. MRN involves training a new text recognition model at each learning step and utilizing it and previously trained models for parallel feature extraction. A domain MLP router is designed to receive these features and predict the probability over the languages. Meanwhile, these features are used for character recognition in their own domain by feeding them to the multi-lingual modeling module. Finally, we fuse the results obtained at both the language domain and character levels to decode the recognized character sequence. + +Our contributions can be summarized as follows. First, we introduce the IMLTR task, the first effort to adapt IL to text recognition. It contributes to the exploration of other + +![](images/6eea735e36321ad4fa21db70179b554d3060043fd89f66eab236167296b745d9.jpg) +Figure 2. The showcase of rehearsal-imbalance. Data-imbalance (top) and class-imbalance (bottom) are severely aggravated from the full dataset to the rehearsal set, while the character classes to be read remain the same, making IMLTR particularly challenging. + +practical scenarios for text recognition. Second, we develop MRN to address the rehearsal-imbalance problem in ILMTR. It is a dynamic and scalable architecture that is compatible with various IL methods and recognition models. Third, experiments on two benchmarks show that MRN significantly outperforms existing general-purpose IL methods, achieving accuracy improvements ranging from $10.3\%$ to $27.4\%$ under different settings. + +# 2. Related Work + +# 2.1. Incremental Learning (IL) + +IL has received intensive research attention over the past few years. Typically, the problem is investigated in the context of image classification, where addressing catastrophic forgetting effectively and efficiently is its core issue. We can broadly classify existing efforts into three categories: regularization [30, 50, 15], rehearsal [36, 9, 1] and dynamic expansion [2, 46, 17, 28]. Regularization methods emphasize constraining weight changes, e.g., allowing only small magnitude changes from the previous weights. It suffers from the problem that the changes do not adequately describe the complex pattern shifts caused by new task learning. Rehearsal methods keep a small amount of old data when training a new task, thus retaining some prior knowledge. Studies in this category focus on the selection of old data and the way it is used. For example, iCaRL was developed to learn an exemplar-based data representation [37]. Alternatively, dynamic expansion methods dynamically create feature extraction sub-networks each associated with one specific task [23, 12, 45, 28]. Early methods required a task identifier to select the correct sub-network at test time. Unfortunately, the assumption is unrealistic as new sam + +![](images/f3c06cfdec4161fb03034253ada4f0c86080b4d294524060cd7509e0dd27f371.jpg) +Figure 3. An overview of MRN. In stage-I, text recognizers are trained language-by-language. While in stage-II, these recognizers are frozen for feature extraction. The Domain MLP Router, which is trained based on the rehearsal set, is proposed to predict the likelihood distribution over the languages. Meanwhile, a padded classification layer is constructed, where the parallel predicted text sequences and likelihood distributions are merged to generate the decoded character sequence. + +plies would not come with their task identifiers. Recently, DER [46] proposed a dynamically expandable representation by discarding the task identifier, where the classifier was finetuned on a balanced exemplar subset to mitigate the task-tendency bias. It attained impressive results. Some recent works [7, 14] studied IL in inhomogeneous or uneven datasets. However, the datasets they adopted are still ideal and cannot sufficiently describe challenges in real-world problems. Moreover, there were also some studies proposed for object detection [21, 10, 48, 47], semantic segmentation [49, 16, 51] and object retrieval [32]. Text recognition has not been studied in IL so far. + +# 2.2. Scene Text Recognition (STR) + +Text recognition is a longstanding research topic in computer vision and pattern recognition. Recent efforts mainly focused on recognizing text in natural scenes, i.e., STR. The task exhibits variations like text distortion, occlusion, blurring, etc., making the recognition challenging. With the advances in deep learning, especially CNN [5, 39, 26, 40] and Transformers [38, 20, 54, 43, 18, 44], STR methods have been pushed forward significantly. + +Multilingual text recognition (MLTR) is an important sub-field of STR. The most popular solution for MLTR was data-joint training [35, 8, 34, 4], where all data was gathered to train a model capable of recognizing all character classes. However, in addition to computational inten + +sive, the approach also had the drawback of being biased toward data-rich languages, while performing poorly in minority languages where training data was scarce. As alternatives, multi-task or ensemble architectures were developed to allow data-rich languages to transfer knowledge to datapoor ones [6, 13]. They alleviated the data scarcity issue to some extent. In addition, Some studies [22, 24, 41, 29] added a script identification step to text recognition. They first identified the language domain and then selected the corresponding recognizer. Although similar to ours in the pipeline, they did not explore dependencies between languages. Moreover, none of them discussed the task within the IL framework. + +# 3. Methodology + +# 3.1. Incremental Multilingual Text Recognition + +Our goal is to develop a unified model that can recognize text instances in different languages, with the model trained incrementally language-by-language. Mathematically, assume there are $I$ kinds of languages $\{\mathcal{D}_1,\dots ,\mathcal{D}_I\}$ , with $\mathcal{D}_i = \left\{(\mathbf{x}_{i,1},y_{i,1}),\dots ,(\mathbf{x}_{i,N(i)},y_{i,N(i)})\right\}$ as the training data at step $i$ (i.e., task $i$ ), where $x_{i,j}$ is the $j$ -th input image and $y_{i,j} \in \mathcal{C}_i$ is its label within the label set $\mathcal{C}_i$ , $N(i)$ is the number of samples in set $\mathcal{D}_i$ . At the $i$ -th learning step, samples of the $i$ -th language will be added to the training set. Therefore, the goal can be formulated as to learn + +new knowledge from the set $\mathcal{D}_i$ , while retaining the previous knowledge learned from old data $\{\mathcal{D}_1, \dots, \mathcal{D}_{i-1}\}$ . The label space of the model is all seen categories $\tilde{\mathcal{C}}_i = \cup_{k=1}^i \mathcal{C}_k$ and the model is expected to predict well on all classes in $\tilde{\mathcal{C}}_i$ . Note that there may be a small overlap between label sets, i.e., $\mathcal{C}_k \cap \mathcal{C}_j \neq \emptyset$ for some $k$ and $j$ . To better fight against catastrophic forgetting, we discuss IMLTR in the rehearsal setting. That is, a small and fix-sized rehearsal set $\mathcal{M}_i$ with a portion of samples from $\{\mathcal{D}_1, \dots, \mathcal{D}_{i-1}\}$ is accessible at incremental step $i$ . + +# 3.2. Challenge and Solution Statement + +To build a recognition model to correctly recognize text instances from all currently seen languages and their character classes, let $x_{n}$ be the text instance to be recognized. $y_{n}^{t} \in \tilde{\mathcal{C}}_{i}$ denotes the $t$ -th character label corresponding to $x_{n}$ . $T(n)$ gives the total number of characters in this instance. IMLTR differs significantly from existing IL settings. For example compared to incremental image classification, standard IL usually has $|\tilde{\mathcal{C}}_i| \leq 100$ and $T(n) = 1$ regardless of the value $n$ . While the size of rehearsal set $\mathcal{M}_i$ is a constant (e.g., 2,000). However, in IMLTR $\mathcal{C}_i$ ranges from dozens of to thousands of character classes for different languages, and $T(n)$ belongs to (1, 25), assuming 25 as the maximized length of a character sequence. Consequently, rehearsal-imbalance becomes a prominent challenge. Due to the limited size of the rehearsal set, it is not rare that a character class appears in the full dataset but is absent from the rehearsal set, as shown in Fig. 2. Thus, the incrementally trained models are likely to forget the absent character classes, despite having learned them previously, which can ultimately hurt the recognition accuracy. + +Although the rehearsal set may not be enough to train a multilingual text recognizer to identify thousands of character classes, it is still sufficient to train a language classifier to recognize the language domains present in the text instance, whose classes are a much smaller number. Once the language domains are identified, we can choose an alternative scheme that involves aggregating the results from corresponding language recognizers to perform the recognition task, thereby bypassing the rehearsal-imbalance issue. + +Motivated by this, we define $\mathcal{H}_i$ and $\varphi_i$ the skeleton network (all except classifier) and classifier trained at the $i$ -th incremental step. Note that $\mathcal{H}_i$ is trained on $\mathcal{D}_i$ , therefore can only recognize character classes of the $i$ -th language in principle. Meanwhile, $\varphi_i$ is set to have $\tilde{\mathcal{C}}_i$ nodes to be compatible with typical IL settings, despite not being taught to recognize character classes of other languages. Then, we can adopt an aggregating-like scheme to implement IMLTR. The learning function can be written as: + +$$ +\sum_ {k = 1} ^ {i} \prod_ {t = 1} ^ {T (n)} \left(P \left(y _ {n} ^ {t} \mid x _ {n}; \mathcal {H} _ {k}, \varphi_ {k}\right) * S \left(d _ {n} ^ {k}\right)\right), \tag {1} +$$ + +where $d_n^k$ is the domain score indicating $x_{n}$ being classified as the $k$ -th language. $S(\cdot)$ is the score quantization function, which can be a one-hot vector (hard-voting) or a likelihood distribution (soft-voting). Eq. 1 treats IMLTR as a weighted ensemble of recognition models trained based on different languages. By doing so, it successfully overcomes the rehearsal-imbalance issue within the IL framework. + +# 3.3. Method Overview + +We propose a Multiplexed Routing Network (MRN) to implement this idea. As illustrated by Fig. 3, it contains two stages, i.e., individual language modeling (stage-I) and multi-lingual modeling (stage-II). In stage-I, given $\mathcal{D}_i$ for the $i$ -th language, we train its recognizer using a popular text recognition model, which can recognize the character classes seen in $\mathcal{D}_i$ . The model is represented as $\mathcal{H}_i$ and $\varphi_i$ . For character classes in $\tilde{\mathcal{C}}_i$ but not in $\mathcal{C}_i$ , we simply truncate gradient propagation from these nodes thus the learned model still focuses on recognizing the $i$ -th language. + +Stage-II aims at building a multilingual routing network for IMLTR. Given a text instance $x_{n} \in \mathcal{D}_{i} \cup \mathcal{M}_{i}$ , we feed it into all the learned $i$ skeleton networks in parallel, while keeping the parameters of the networks frozen for targeted feature extraction. It extracts $i$ sets of features, each associated with a certain language. The features are further fed into a Domain MLP Router (DM-Router) module, which is designed for domain score estimation, i.e., estimating the likelihood that the text instance belongs to the languages. Meanwhile, the $i$ sets of features are fed to their respective classifiers, where the corresponding recognition character sequences are obtained. To merge their recognition, we pad the classification nodes with zeros to $|\tilde{\mathcal{C}}_i|$ , ensuring that all classifiers are aligned to the same dimension. As a result, their recognized characters can be merged using weighted element-wise addition, where the weights are the domain scores estimated using DM-Router. Finally, the recognition is conducted by applying a CTC- or attention-based decoding. Since DM-Router plays a critical role in the proposed method, we provide a detailed illustration below. + +# 3.4. Domain MLP Router + +DM-Router uses features that are biased towards different language domains to discriminate the language domain of text instances. It accomplishes this by leveraging both the rehearsal set and the language data that arrives at the $i$ -th step. While training a separate single-network classifier, which takes an image as input and outputs the language domain scores, can identify the language domains, we believe that this approach overlooks inter-domain dependencies that could be explored for better identification. For instance, different languages may have distinct appearance patterns, such as strokes, which differ significantly between Eastern Asian languages and Latin. Additionally, their features ex + +![](images/5c56d96ed465594d9facb88afea3ddac6cd2695f29f26483ee5717e0268a24e3.jpg) +Figure 4. Detail structure of Domain MLP Router (DM-Router). Spatial-domain and Channel-domain dependencies are explored and fused to generate the language domain score distribution. + +hibit different frequency distributions, which can also aid language identification. + +To achieve this goal, DM-Router accepts all $i$ sets of features extracted previously as input and mines the spatial-domain and channel-domain dependencies for better language identification. The detailed structure of DM-Router is shown in Fig. 4. Features from different skeleton networks are concatenated, generating a feature cubic with size $P \times D \times C$ , where $P$ , $D$ , and $C$ stand for the number of reshaped spatial patches, language domains, and feature channels, respectively. Then, a linear projection is applied along the channel dimension (C Proj), followed by reshaping the cubic from the patch-domain dimension. Next, a gated-mechanism is followed to generate the attention scores between the patch and domain. This is achieved by applying linear projection along the patch-domain dimension, followed by a layer norm and a feature dot product. We reshape the generated feature back to a feature cubic of the same size and merge it with the original cubic. The operations above explore the spatial-domain dependency. A similar operation is then applied to the merged feature cubic to explore the channel-domain dependence. In the following, the explored feature cubic gradually shrinks to a $D$ -dimensional score vector that indicates the probability over the languages. It represents the likelihood of each language domain for the input text instance. + +DM-Router is an MLP-based attention network that targets language domain weighting. Note that there are a few similar solutions in the literature. Expert Gate (E-Gate) [2] developed an expert gating network that identified which model could be employed based on image reconstruction loss. However, it might not effectively discriminate IMLTR due to some languages exhibiting character class overlapping, which can cause classification confusion. On the other hand, multilingual OCR [29] determines the languages by + +
DatasetcategoriesTask1Task2Task3Task4Task5Task6
ChineseLatinJapaneseKoreanArabicBangla
MLT17[35]train instance2687474114609563137113237
test instance5291107313501230983713
train class18953251620112473112
MLT19[34]train instance2897529215324610742303542
test instance3225882590679470393
train class20862201728116073102
+ +Table 1. MLT17 and MLT19 statistics in our experiments. + +script recognition and selected the corresponding model for recognition. Unlike these hard-voting methods, MRN employs soft-voting, which allows for the use of knowledge from other languages. For instance, Japanese has the ability to correct Chinese to some extent, given that they share some common words and similar strokes. + +# 3.5. Training Loss + +MRN has two loss terms. One for multilingual text recognition while the other for language domain prediction. The total loss function is written as: + +$$ +\mathcal {L} _ {\text {t o t a l}} = \mathcal {L} _ {\mathrm {c l f}} + \alpha \mathcal {L} _ {\text {d o m a i n}}, \tag {2} +$$ + +where $\alpha$ is an empirical hyperparameter to balance the two. + +MRN shows two advantages in dealing with rehearsal-imbalance. First, it ensures fair use of language. As previously mentioned, data distribution is uneven across different languages, and if not addressed during model training, it may lead to bias in the resulting model. By adopting language-by-language training and parameter freezing, data-rich and data-poor languages are treated equally, and class-imbalance is also alleviated. Second, MRN makes use of inter-lingual dependency in two ways: through the DM-Router described earlier, and through recognition score merging. When a character is recognized by more than one language, it receives confidence scores from each of them, allowing for the utilization of inter-lingual dependencies. + +# 4. Experiments + +# 4.1. Datasets and Implementation Details + +ICDAR 2017 MLT (MLT17) [35] has 68,613 training instances and 16,255 validation instances, which are from 6 scripts and 9 languages: Chinese, Japanese, Korean, Bangla, Arabic, Italian, English, French, and German. The last four use Latin script. The samples are from natural scenes with challenges like blur, occlusion, and distortion. We use the validation set for test due to the unavailability of test data. Tasks are split by scripts and modeled sequentially. Special symbols are discarded at the preprocessing step as with no linguistic meaning. + +ICDAR 2019 MLT (MLT19) [34] has 89,177 text instances coming from 7 scripts. Since the inaccessibility of test set, we randomly split the training instances to 9:1 script-by-script, for model training and test. To be consistent with + +
MLT17MLT19
Model: CRNN (TPAMI'17) [39]
T1T2T3T4T5T6AVGT1T2T3T4T5T6AVG
Bound------92.1------84.9
Baseline91.151.751.037.229.322.347.185.149.646.535.527.620.744.2
LwF (TPAMI'17)[31]91.153.753.438.229.723.748.385.151.649.236.527.722.045.3
EWC (PNAS'17)[30]91.156.550.437.230.521.547.985.155.546.335.828.819.945.2
WA (CVPR'20) [52]91.154.648.738.228.523.147.485.152.244.336.726.821.644.4
DER (CVPR'21)[46]91.176.355.846.439.335.857.585.175.240.445.136.634.252.8
MRN91.188.677.273.769.869.878.485.185.173.268.365.365.573.7
Model: TRBA (ICCV'19) [3]
T1T2T3T4T5T6AVGT1T2T3T4T5T6AVG
Bound------94.9------90.5
Baseline91.349.647.336.128.624.046.185.449.444.034.827.423.144.0
LwF (TPAMI'17)[31]91.355.738.828.722.618.742.685.454.235.027.220.517.039.9
EWC (PNAS'17)[30]91.350.443.633.125.621.944.385.449.440.631.724.820.642.1
WA (CVPR'20) [52]91.345.441.830.723.519.642.185.444.037.929.221.618.139.4
DER (CVPR'21)[46]91.360.153.038.831.428.650.585.460.750.337.230.328.148.7
MRN91.387.975.872.271.568.777.985.484.573.267.866.764.873.7
Model: SVTR-Base (IJCAI'22) [18]
T1T2T3T4T5T6AVGT1T2T3T4T5T6AVG
Bound------90.1------83.2
Baseline90.632.540.530.824.519.939.884.831.337.029.222.619.137.3
LwF (TPAMI'17)[31]90.628.038.429.924.118.338.284.827.034.628.422.317.035.7
EWC (PNAS'17)[30]90.633.041.231.124.620.040.184.831.337.729.522.619.037.5
WA (CVPR'20) [52]90.628.037.930.424.819.838.684.826.734.628.322.618.635.9
DER (CVPR'21)[46]90.674.555.755.049.545.761.884.871.652.952.246.643.658.6
MRN90.686.473.965.663.458.173.084.883.769.464.457.853.168.9
+ +Table 2. Accuracy (%) of different text recognizers and incremental learning methods on MLT17 and MLT19. Baseline denotes the model trained solely based on the rehearsal set and language data arrived at that step. The language incremental order is introduced in Sec. 4.1. + +MLT2017 dataset, we discard the Hindi script and also special symbols. Statistics of the two datasets are shown Tab. 1. + +Height and width of the images are scaled uniformly to $32 \times 256$ . The maximum length of a character sequence is set to 25. All models, each corresponding to a language domain, are trained with 10,000 iterations, using the Adam optimizer and the one-cycle learning rate scheduler [42] with a maximum learning rate of 0.0005. The batch size is set to 256. To mitigate the dataset variance, in each batch we evenly sample training samples from both datasets, that is, half from MLT17 and half from MLT19. A random order for the six languages is employed, which is Chinese, Latin, Japanese, Korean, Arabic, Bangla. Other orders will be discussed later. For the rehearsal setting, we limit the rehearsal size to 2000 samples unless specified. We conduct the experiments using two NVIDIA RTX 3090 GPUs. + +# 4.2. Comparison with Existing Methods + +We equip MRN with different text recognizers and combine them with different IL methods. Specifically, we consider three typical STR schemes: CTC-based (CRNN [39]), attention-based (TRBA [3]), and ViT-based (SVTR [18]). Meanwhile, four popular IL methods are chosen, i.e., Lwf + +[31], EWC [30], WA [52] and DER [46]. All models retain their original settings, except for the removal of the auxiliary loss of DER, which reduces its performance in our task. + +In Tab. 2, we give the results at different incremental steps, where the language is added one-by-one and the average accuracy of different methods is reported. Bound, the model trained using all training data, is also listed as the oracle for reference. As can be seen, MRN consistently outperforms all the compared methods by significant margins under different settings, no matter which recognizer is employed. When looking into the general-purpose IL methods, their accuracy mostly decreased rapidly as the incremental steps due to the affection of rehearsal-imbalance. DER has the highest accuracy among them, as its dynamic expansion architecture has certain advantages in fighting against catastrophic forgetting. However, there is still a clear accuracy gap between DER and our MRN, and the gap widens as the incremental step increases. We attribute the accuracy improvement achieved by MRN to two factors. First, IMLTR is a task that differs significantly from image classification, where most IL methods have been experimented on. These methods do not well accommodate the challenge raised by IMLTR. For example, the rehearsal-imbalance issue. Sec- + +ond, MRN develops an elegant pipeline that implements the recognition in a domain routing and result fusion manner. It works particularly well for scenarios where incremental tasks exhibit significant differences. + +When comparing the recognizers, MRN equipped with CRNN has the highest overall accuracy. The result is interesting as CRNN has a simpler architecture and generally performs worse than the other two methods on typical STR tasks. We attribute this to parameter freezing, where the feature extraction backbone (e.g., $\mathcal{H}_i$ ) and the decoder cannot be jointly optimized. Therefore, advanced models are more severely affected, while the simpler one is less affected and can better mitigate catastrophic forgetting. + +
modelMLT17MLT19
AvgLastAvgLast
None64.837.960.835.6
MLP68.560.565.356.3
CycleMLP[11]75.563.571.160.0
ViP[25]76.462.672.259.6
gMLP[33]77.568.273.164.2
DM-Router78.469.873.865.5
+ +# 4.3. Ablation Study + +We perform a series of controlled experiments to gain a deeper understanding of MRN. CRNN is employed as the text recognizer unless specified. + +Effectiveness of DM-Router: There are multiple ways to deduce the language domain scores. We enumerate several of them that have been used in existing studies, as shown in Tab. 3. None denotes no dependence is explored, which corresponds to the worst result. It, in turn, demonstrates the necessity of utilizing language dependence. Among the rest competitors, MLP enables a naive learning mechanism while the remaining three are based on more advanced MLP-like models, which are typically more effective. Despite this, DM-Router attains the highest accuracy among the methods. The results clearly demonstrate the rationality of the DM-Router structure in terms of language dependence exploration. + +Influence of the size of the rehearsal set: We conduct analytical experiments to evaluate the influence of the rehearsal size on the accuracy of Lwf [31], DER [46] and MRN. Fig. 4 shows the accuracy under different rehearsal sizes. As anticipated, increasing the rehearsal set size leads to accuracy gains, as more past memories are retained. We observe that larger gains are obtained in LwF and DER, particularly DER. This reveals the accuracy of general-purpose IL methods is largely affected by the rehearsal size in IMLTR, while MRN is less affected. MRN has already achieved relatively high accuracy, and the performance of MRN in iden + +Table 3. Performance comparisons on different MLP models. + +
SizeMethodMLT17MLT19
AvgLastAvgLast
2kLwF[31]48.323.745.422.0
DER[46]57.535.852.834.2
MRN78.469.873.865.5
3kLwF[31]52.224.948.823.6
DER[46]60.942.058.740.6
MRN80.272.775.468.2
4kLwF[31]55.527.552.226.1
DER[46]66.448.763.846.6
MRN81.575.076.570.6
+ +Table 4. Ablation study on the size of the rehearsal set. + +
OrderMethodMLT17MLT19
AvgLastAvgLast
O1LwF[31]48.323.745.422.0
DER[46]57.535.852.834.2
MRN78.469.873.865.5
O2LwF[31]46.923.843.122.9
DER[46]63.139.158.739.6
MRN80.565.374.161.5
O3LwF[31]57.734.755.734.2
DER[46]69.641.365.738.2
MRN82.970.678.366.0
+ +Table 5. Ablation study on language order. + +
Sampling StrategyMLT17MLT19
AvgLastAvgLast
Confidence56.443.854.041.2
Length71.050.366.648.9
Frequency72.656.667.853.7
Random78.469.873.865.5
+ +Table 6. Ablation study on rehearsal sampling strategy. + +tifying language domains is less affected by the rehearsal size. The results indicate that MRN is robust to rehearsal scarcity and can better fight against data imbalance. + +Influence of language incremental order: In addition to the order in Sec. 4.1 (O1), we assess two other orders as follows: 1) Arabic, Chinese, Latin, Japanese, Bangla, Korean (O2); 2) Latin, Arabic, Bangla, Chinese, Japanese, Korean (O3). The two orders either alternate the three Eastern Asia languages, which have large vocabularies and show more stroke commonalities, or group them together at the end. We also include Lwf and DER for comparison. + +Tab. 5 gives the results and two observations. First, O3 shows the best accuracy, while O2 also performs better than O1. It is because the three Eastern Asia languages are more difficult to recognize due to their large vocabulary sizes, therefore introducing them later leads to a better average accuracy. Meanwhile, putting them together also reduces the + +
MethodSelectModelVotingMLT17MLT19Params (M)FLOPs (G)
AvgLastAvgLast
Baseline---47.122.344.220.79.53.5
DER[46]---57.535.852.834.233.812.3
E-Gate[2]Re-Const.AutoencoderHard37.215.234.814.232.512.2
E-Gate[2]StackingAutoencoderHard62.715.259.314.235.512.4
MRNStackingDM-RouterHard74.462.969.957.733.512.4
MRNStackingDM-RouterSoft78.469.873.865.533.512.4
+ +Table 7. Comparisons on different routing strategies. + +oscillation during parameter learning and generates a better model, due to their stroke commonalities. The experiment suggests that careful selection of the order of languages can attain better accuracy. Second, O1 shows the largest accuracy gaps between MRN and other methods. This is because in O1, the large vocabulary languages appear earlier, while the rehearsal set is fix-sized, resulting in the most severe class imbalance among the three orders. The result indicates that MRN can better handle class imbalance. + +Influence of rehearsal sampling strategy: The determination of text instances being sampled to the rehearsal set is an issue also worthy of abulating. Tab. 6 gives the accuracy of four sampling strategies, i.e., Confidence that selects instances with the highest recognition scores, Length that selects instances with the largest number of characters, Frequency that selects instances with the most frequently occurred characters, and Random adopted in our MRN that randomly selects the instances. Interestingly, Random gives the best accuracy. We attribute the reason to: the rehearsal set obtained from Confidence or Frequency cannot fully represent the true data distribution, where difficult or less occurred instances are excluded. Length, to some extent, overlooks the varying-length characteristic of IMLTR. On the contrary, Random, despite simple, well mimics the underlying data distribution and well handles the variable length challenge. + +Comparison on routing strategy: We compare MRN with E-Gate and its variants. E-Gate [2] treats different subnetworks as experts, and each time selects the most appropriate one for inference. In Tab. 7 we provide the model details. Raw E-Gate performs poorly in IMLTR. When stacking is used to build feature extractors, the accuracy improves significantly and outperforms DER. We also evaluate MRN with hard-voting. It reports a worse result. Compared to other routing strategies, our MRN shows clear superiority in terms of accuracy, while incurring only a negligible cost in parameters and computational complexity. + +# 4.4. Qualitative Results Analysis + +Fig. 5 gives several recognition results of MRN. It correctly read instances of different languages, even with the presence of common recognition difficulties. More importantly, MRN also recognizes character classes that are not + +![](images/a5ec3628cc6be67d97e1f80b18bad2db4fc01b96eb6ed3e3c4933d976f9731a3.jpg) +Figure 5. Illustrative recognition examples, where red denotes characters that are absent from the rehearsal set. + +present in the rehearsal set. These results again demonstrate that our MRN is effective in handling rehearsal-imbalance and can generalize well to unseen character classes. + +# 5. Conclusion + +In this work, we introduce a new task called incremental multilingual text recognition (IMLTR). IMLTR handles text recognition in an incremental learning setting, therefore is suitable for applications like streaming data processing. IMLTR faces a distinct problem of rehearsal-imbalance, including data imbalance, class imbalance, and variable character length. To address this challenge, we designed a Multiplexed Routing Network (MRN) that first trains a multi-language correlated DM-router to weight the language domains, and then votes the separately trained recognition branches for final text recognition. Experiments on public benchmarks show that MRN significantly outperforms existing general-purpose IL methods by large margins. As the first attempt to apply IL to multilingual text recognition, we hope that this work will broaden the applications of text recognition and inspire further research in this area. + +Acknowledgments This project was supported by National Key R&D Program of China (No. 2022YFB3104703) and in part by the National Natural Science Foundation of China (No. 62172103) + +# References + +[1] Rahaf Aljundi, Francesca Babiloni, Mohamed Elhoseiny, Marcus Rohrbach, and Tinne Tuytelaars. Memory aware synapses: Learning what (not) to forget. In ECCV, pages 139-154, 2018. 2 +[2] Rahaf Aljundi, Punarjay Chakravarty, and Tinne Tuytelaars. Expert gate: Lifelong learning with a network of experts. In CVPR, July 2017. 2, 5, 8 +[3] Jeonghun Baek, Geewook Kim, Junyeop Lee, Sungrae Park, Dongyoon Han, Sangdoo Yun, Seong Joon Oh, and Hwalsuk Lee. What is wrong with scene text recognition model comparisons? dataset and model analysis. In ICCV, pages 4714-4722, 2019. 6 +[4] Youngmin Baek, Seung Shin, Jeonghun Baek, Sungrae Park, Junyeop Lee, Daehyun Nam, and Hwalsuk Lee. Character region attention for text spotting. In ECCV, pages 504-521. Springer, 2020. 1, 3 +[5] Jinfeng Bai, Zhineng Chen, Bailan Feng, and Bo Xu. Chinese image text recognition on grayscale pixels. In 2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), pages 1380-1384. IEEE, 2014. 3 +[6] Jinfeng Bai, Zhineng Chen, Bailan Feng, and Bo Xu. Image character recognition using deep convolutional neural network learned from different languages. In 2014 IEEE International Conference on Image Processing (ICIP), pages 2560-2564. IEEE, 2014. 3 +[7] Eden Belouadah and Adrian Popescu. II2m: Class incremental learning with dual memory. In ICCV, pages 583-592, 2019. 1, 2, 3 +[8] Michal Bušta, Yash Patel, and Jiri Matas. E2e-plt-an unconstrained end-to-end method for multi-language scene text. In ACCV, pages 127–143. Springer, 2018. 1, 3 +[9] Francisco M Castro, Manuel J Marín-Jiménez, Nicolás Guil, Cordelia Schmid, and Karteek Alahari. End-to-end incremental learning. In ECCV, pages 233-248, 2018. 2 +[10] Li Chen, Chunyan Yu, and Lvcai Chen. A new knowledge distillation for incremental object detection. In IJCNN, pages 1-7. IEEE, 2019. 3 +[11] Shoufa Chen, Enze Xie, Chongjian GE, Runjian Chen, Ding Liang, and Ping Luo. CycleMLP: A MLP-like architecture for dense prediction. In ICLR, 2022. 7 +[12] Mark Collier, Efi Kokiopoulou, Andrea Gesmundo, and Jesse Berent. Routing networks with co-training for continual learning. ICML, 2020. 2 +[13] Jia Cui, Brian Kingsbury, Bhuvana Ramabhadran, George Saon, Tom Sercu, Kartik Audhkhasi, Abhinav Sethy, Markus Nussbaum-Thom, and Andrew Rosenberg. Knowledge distillation across ensembles of multilingual models for low-resource languages. In ICASSP, pages 4825-4829, 2017. 3 +[14] Matthias De Lange, Rahaf Aljundi, Marc Masana, Sarah Parisot, Xu Jia, Aleš Leonardis, Gregory Slabaugh, and Tinne Tuytelaars. A continual learning survey: Defying forgetting in classification tasks. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(7):3366-3385, 2022. 1, 2, 3 + +[15] Prithviraj Dhar, Rajat Vikram Singh, Kuan-Chuan Peng, Ziyan Wu, and Rama Chellappa. Learning without memorizing. In CVPR, pages 5138-5146, 2019. 2 +[16] Arthur Douillard, Yifu Chen, Arnaud Dapogny, and Matthieu Cord. Plop: Learning without forgetting for continual semantic segmentation. In CVPR, pages 4040-4050, 2021. 3 +[17] Arthur Douillard, Alexandre Ramé, Guillaume Couairon, and Matthieu Cord. Dytox: Transformers for continual learning with dynamic token expansion. In CVPR, pages 9285–9295, 2022. 2 +[18] Yongkun Du, Zhineng Chen, Caiyan Jia, Xiaoting Yin, Tianlun Zheng, Chenxia Li, Yuning Du, and Yu-Gang Jiang. SVTR: scene text recognition with a single visual model. In IJCAI, 2022. 3, 6 +[19] Shancheng Fang, Zhendong Mao, Hongtao Xie, Yuxin Wang, Chenggang Yan, and Yongdong Zhang. Abinet++: Autonomous, bidirectional and iterative language modeling for scene text spotting. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 1 +[20] Shancheng Fang, Hongtao Xie, Yuxin Wang, Zhendong Mao, and Yongdong Zhang. Read like humans: Autonomous, bidirectional and iterative language modeling for scene text recognition. In CVPR, pages 7094-7103, 2021. 3 +[21] Tao Feng, Mang Wang, and Hangjie Yuan. Overcoming catastrophic forgetting in incremental object detection via elastic response distillation. In CVPR, pages 9427-9436, 2022. 3 +[22] Yasuhisa Fujii, Karel Driesen, Jonathan Baccash, Ash Hurst, and Ashok C Popat. Sequence-to-label script identification for multilingualOCR. In ICDAR, volume 1, pages 161-168. IEEE, 2017. 1, 3 +[23] Siavash Golkar, Michael Kagan, and Kyunghyun Cho. Continual learning via neural pruning. NIPS, 2019. 2 +[24] Lluis Gomez, Anguelos Nicolaou, and Dimosthenis Karatzas. Improving patch-based scene text script identification with ensembles of conjoined networks. Pattern Recognition, 67:85-96, 2017. 1, 3 +[25] Qibin Hou, Zihang Jiang, Li Yuan, Ming-Ming Cheng, Shuicheng Yan, and Jiashi Feng. Vision permutator: A permutable mlp-like architecture for visual recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 7 +[26] Wenyang Hu, Xiaocong Cai, Jun Hou, Shuai Yi, and Zhiping Lin. Gtc: Guided training of ctc towards efficient and accurate scene text recognition. In AAAI, volume 34, pages 11005-11012, 2020. 3 +[27] Xinting Hu, Kaihua Tang, Chunyan Miao, Xian-Sheng Hua, and Hanwang Zhang. Distilling causal effect of data in class incremental learning. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3957-3966, 2021. 1 +[28] Bingchen Huang, Zhineng Chen, Peng Zhou, Jiayin Chen, and Zuxuan Wu. Resolving task confusion in dynamic expansion architectures for class incremental learning. In AAAI, volume 37, pages 908-916, 2023. 1, 2 + +[29] Jing Huang, Guan Pang, Rama Kovvuri, Mandy Toh, Kevin J Liang, Praveen Krishnan, Xi Yin, and Tal Hassner. A multiplexed network for end-to-end, multilingualOCR. In CVPR, pages 4547-4557, 2021. 1, 3, 5 +[30] James Kirkpatrick, Razvan Pascanu, Neil Rabinowitz, Joel Veness, Guillaume Desjardins, Andrei A Rusu, Kieran Milan, John Quan, Tiago Ramalho, Agnieszka Grabska-Barwinska, et al. Overcoming catastrophic forgetting in neural networks. Proceedings of the national academy of sciences, 114(13):3521-3526, 2017. 2, 6 +[31] Zhizhong Li and Derek Hoiem. Learning without forgetting. IEEE transactions on pattern analysis and machine intelligence, 40(12):2935-2947, 2017. 6, 7 +[32] An-An Liu, Haochun Lu, Heyu Zhou, Tianbao Li, and Mohan Kankanhalli. Balanced class-incremental 3d object classification and retrieval. IEEE Transactions on Knowledge and Data Engineering, 2023. 3 +[33] Hanxiao Liu, Zihang Dai, David So, and Quoc V Le. Pay attention to mlps. NIPS, 34:9204-9215, 2021. 7 +[34] Nibal Nayef, Yash Patel, Michal Busta, Pinaki Nath Chowdhury, Dimosthenis Karatzas, Wafa Khlif, Jiri Matas, Umapada Pal, Jean-Christophe Burie, Cheng-lin Liu, et al. Icdar2019 robust reading challenge on multi-lingual scene text detection and recognition—rrc-plt-2019. In ICDAR, pages 1582–1587. IEEE, 2019. 1, 3, 5 +[35] Nibal Nayef, Fei Yin, Imen Bizid, Hyunsoo Choi, Yuan Feng, Dimosthenis Karatzas, Zhenbo Luo, Umapada Pal, Christophe Rigaud, Joseph Chazalon, et al. Icdar2017 robust reading challenge on multi-lingual scene text detection and script identification-rrc-plt. In ICDAR, volume 1, pages 1454-1459. IEEE, 2017. 3, 5 +[36] German I Parisi, Ronald Kemker, Jose L Part, Christopher Kanan, and Stefan Wermter. Continual lifelong learning with neural networks: A review. Neural Networks, 113:54-71, 2019. 2 +[37] Sylvestre-Alvise Rebuffi, Alexander Kolesnikov, Georg Sperl, and Christoph H Lampert. icarl: Incremental classifier and representation learning. In CVPR, pages 2001–2010, 2017. 1, 2 +[38] Fenfen Sheng, Zhineng Chen, and Bo Xu. Ntrr: A no-recurrence sequence-to-sequence model for scene text recognition. In ICDAR, pages 781-786, 2019. 1, 3 +[39] Baoguang Shi, Xiang Bai, and Cong Yao. An end-to-end trainable neural network for image-based sequence recognition and its application to scene text recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 39(11):2298-2304, 2017. 1, 3, 6 +[40] Baoguang Shi, Mingkun Yang, Xinggang Wang, Pengyuan Lyu, Cong Yao, and Xiang Bai. Aster: An attentional scene text recognizer with flexible rectification. IEEE Transactions on Pattern Analysis and Machine Intelligence, 41(9):2035-2048, 2018. 1, 3 +[41] Baoguang Shi, Cong Yao, Chengquan Zhang, Xiaowei Guo, Feiyue Huang, and Xiang Bai. Automatic script identification in the wild. In ICDAR, pages 531-535. IEEE, 2015. 3 +[42] Leslie N Smith and Nicholay Topin. Super-convergence: Very fast training of neural networks using large learning + +rates. In Artificial intelligence and machine learning for multi-domain operations applications, volume 11006, pages 369-386. SPIE, 2019. 6 +[43] Yuxin Wang, Hongtao Xie, Shancheng Fang, Jing Wang, Shenggao Zhu, and Yongdong Zhang. From two to one: A new scene text recognizer with visual language modeling network. In ICCV, pages 14174-14183, 2021. 1, 3 +[44] Yuxin Wang, Hongtao Xie, Shancheng Fang, Mengting Xing, Jing Wang, Shenggao Zhu, and Yongdong Zhang. Petr: Rethinking the capability of transformer-based language model in scene text recognition. IEEE Transactions on Image Processing, 31:5585-5598, 2022. 3 +[45] Yeming Wen, Dustin Tran, and Jimmy Ba. Batchsemble: an alternative approach to efficient ensemble and lifelong learning. In ICLR, 2020. 2 +[46] Shipeng Yan, Jiangwei Xie, and Xuming He. Der: Dynamically expandable representation for class incremental learning. In CVPR, pages 3014-3023, 2021. 1, 2, 3, 6, 7, 8 +[47] Dongbao Yang, Yu Zhou, Xiaopeng Hong, Aoting Zhang, and Weiping Wang. One-shot replay: Boosting incremental object detection via retrospecting one object. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 37, pages 3127-3135, 2023. 3 +[48] Dongbao Yang, Yu Zhou, Aoting Zhang, Xurui Sun, Dayan Wu, Weiping Wang, and Qixiang Ye. Multi-view correlation distillation for incremental object detection. Pattern Recognition, 131:108863, 2022. 3 +[49] Guanglei Yang, Enrico Fini, Dan Xu, Paolo Rota, Mingli Ding, Moin Nabi, Xavier Alameda-Pineda, and Elisa Ricci. Uncertainty-aware contrastive distillation for incremental semantic segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 3 +[50] Friedemann Zenke, Ben Poole, and Surya Ganguli. Continual learning through synaptic intelligence. In ICML, pages 3987-3995. PMLR, 2017. 2 +[51] Chang-Bin Zhang, Jia-Wen Xiao, Xialei Liu, Ying-Cong Chen, and Ming-Ming Cheng. Representation compensation networks for continual semantic segmentation. In CVPR, pages 7053-7064, 2022. 1, 3 +[52] Bowen Zhao, Xi Xiao, Guojun Gan, Bin Zhang, and Shu-Tao Xia. Maintaining discrimination and fairness in class incremental learning. In CVPR, pages 13208-13217, 2020. 1, 6 +[53] Tianlun Zheng, Zhineng Chen, Jinfeng Bai, Hongtao Xie, and Yu-Gang Jiang. Tps++: Attention-enhanced thin-plate spline for scene text recognition. *IJCAI*, 2023. 1 +[54] Tianlun Zheng, Zhineng Chen, Shancheng Fang, Hongtao Xie, and Yu-Gang Jiang. Cdistnet: Perceiving multi-domain character distance for robust text recognition. arXiv preprint arXiv:2111.11011, 2021. 3 \ No newline at end of file diff --git a/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/images.zip b/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..a50c65a15482b0f6fa630933c59d437e07cfb2d7 --- /dev/null +++ b/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:22de5c54ff9d841322a793ad62f123fc1d6b550eeff2ca8cb1d8580b0bb75a3a +size 694328 diff --git a/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/layout.json b/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..4738e5864fcc2fdde10856c60d308cdca71de5b3 --- /dev/null +++ b/2023/MRN_ Multiplexed Routing Network for Incremental Multilingual Text Recognition/layout.json @@ -0,0 +1,7489 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 153, + 103, + 440, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 153, + 103, + 440, + 140 + ], + "spans": [ + { + "bbox": [ + 153, + 103, + 440, + 140 + ], + "type": "text", + "content": "MRN: Multiplexed Routing Network for Incremental Multilingual Text Recognition" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "spans": [ + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "text", + "content": "Tianlun Zheng" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "inline_equation", + "content": "^{1,2}" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "text", + "content": ", Zhineng Chen" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "inline_equation", + "content": "^{1,2*}" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "text", + "content": ", Bingchen Huang" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "inline_equation", + "content": "^{1,2}" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "text", + "content": ", Wei Zhang" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "text", + "content": " and Yu-Gang Jiang" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "inline_equation", + "content": "^{1,2}" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "text", + "content": "\\\n" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "text", + "content": "School of Computer Science, Fudan University, China\\\n" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "text", + "content": "Shanghai Collaborative Innovation Center of Intelligent Visual Computing, China\\\n" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 78, + 160, + 515, + 217 + ], + "type": "text", + "content": "Gaoding AI, China" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 59, + 219, + 533, + 232 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 219, + 533, + 232 + ], + "spans": [ + { + "bbox": [ + 59, + 219, + 533, + 232 + ], + "type": "text", + "content": "{t1zheng21, bchuang21}@m.fudan.edu.cn, {zhinchen, ygj}@fudan.edu.cn, wzhang.cu@gmail.com" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 258, + 192, + 271 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 258, + 192, + 271 + ], + "spans": [ + { + "bbox": [ + 143, + 258, + 192, + 271 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 284, + 290, + 559 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 284, + 290, + 559 + ], + "spans": [ + { + "bbox": [ + 47, + 284, + 290, + 559 + ], + "type": "text", + "content": "Multilingual text recognition (MLTR) systems typically focus on a fixed set of languages, which makes it difficult to handle newly added languages or adapt to ever-changing data distribution. In this paper, we propose the Incremental MLTR (IMLTR) task in the context of incremental learning (IL), where different languages are introduced in batches. IMLTR is particularly challenging due to rehearsal-imbalance, which refers to the uneven distribution of sample characters in the rehearsal set, used to retain a small amount of old data as past memories. To address this issue, we propose a Multiplexed Routing Network (MRN). MRN trains a recognizer for each language that is currently seen. Subsequently, a language domain predictor is learned based on the rehearsal set to weigh the recognizers. Since the recognizers are derived from the original data, MRN effectively reduces the reliance on older data and better fights against catastrophic forgetting, the core issue in IL. We extensively evaluate MRN on MLT17 and MLT19 datasets. It outperforms existing general-purpose IL methods by large margins, with average accuracy improvements ranging from " + }, + { + "bbox": [ + 47, + 284, + 290, + 559 + ], + "type": "inline_equation", + "content": "10.3\\%" + }, + { + "bbox": [ + 47, + 284, + 290, + 559 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 47, + 284, + 290, + 559 + ], + "type": "inline_equation", + "content": "35.8\\%" + }, + { + "bbox": [ + 47, + 284, + 290, + 559 + ], + "type": "text", + "content": " under different settings. Code is available at https://github.com/simplify23/MRN." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 581, + 128, + 593 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 581, + 128, + 593 + ], + "spans": [ + { + "bbox": [ + 47, + 581, + 128, + 593 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 601, + 287, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 601, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 601, + 287, + 696 + ], + "type": "text", + "content": "Scene text recognition (STR) is a task aiming to read text in natural scenes. Recent advances in deep learning have significantly improved the accuracy of STR, allowing it to recognize text in the presence of font variations, distortions, and noise interference [39, 40, 43, 38, 19, 53]. As countries and cultures are more interconnected, the task of simultaneously recognizing multiple languages, i.e., multilingual text recognition (MLTR), has also become more important." + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 313, + 258, + 540, + 397 + ], + "blocks": [ + { + "bbox": [ + 313, + 258, + 540, + 397 + ], + "lines": [ + { + "bbox": [ + 313, + 258, + 540, + 397 + ], + "spans": [ + { + "bbox": [ + 313, + 258, + 540, + 397 + ], + "type": "image", + "image_path": "0c5aa2c85122bfbba53b92a9d91ec6ed250dfb11f4d40034fa9312614dd0c45d.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 400, + 547, + 467 + ], + "lines": [ + { + "bbox": [ + 305, + 400, + 547, + 467 + ], + "spans": [ + { + "bbox": [ + 305, + 400, + 547, + 467 + ], + "type": "text", + "content": "Figure 1. Incremental multilingual text recognition (IMLTR) focuses on the practical scenario where different languages are introduced sequentially. The goal is to accurately recognize the newly introduced language while maintaining high recognition accuracy for previously seen languages. IMLTR introduces a task focusing on text recognition that faces rehearsal-imbalance challenges." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 494, + 547, + 578 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 494, + 547, + 578 + ], + "spans": [ + { + "bbox": [ + 304, + 494, + 547, + 578 + ], + "type": "text", + "content": "Existing methods typically address this challenge by training on mixed multilingual data [8, 4, 34] or designing independent language blocks [29, 22, 24]. However, when each time a new language is added, the above methods need retraining on a dataset mixing the old and new languages. This increases the training cost [37, 46] and also may lead to an imbalance [7, 14] between old and new data." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 582, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 547, + 713 + ], + "type": "text", + "content": "Incremental learning (IL) is designed for scenarios where new data is continuously learned and typically, the old samples are maintained by a small ratio. The collection of old samples is referred to as the rehearsal set [51, 27], which serves as limited past memories. IL aims to learn the new data well while minimizing forgetting the past learned knowledge. Most existing studies [37, 7, 52, 28] conduct experiments on balanced datasets and maintain a constant number of classes at each learning step. However, in real-world scenarios, the number of classes and samples may differ across steps, leading to imbalanced datasets. To ad" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 703, + 138, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 703, + 138, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 703, + 138, + 712 + ], + "type": "text", + "content": "*Corresponding Author." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "18644" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": "dress these issues, IL2M [7] alleviated class-imbalance by storing statistics of old classes rather than samples. Delange et al. De Lange et al. [14] surveyed typical IL methods on datasets and solutions with different data imbalances. Despite progress made, research on data and class imbalance is still in its infancy stage. Moreover, as illustrated in Fig. 1, there is currently no research introducing IL to STR." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 158, + 288, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 158, + 288, + 266 + ], + "spans": [ + { + "bbox": [ + 46, + 158, + 288, + 266 + ], + "type": "text", + "content": "We rewrite MLTR in the context of IL. Languages are treated as tasks and characters are their classes. During training, the model only observes the newly arrived language data and a small amount of data from old languages. The recognition model is expected to maintain the ability to recognize characters of all languages that it has encountered before, regardless of whether their data are still available or discarded. We term this problem incremental multilingual text recognition (IMLTR)." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 267, + 288, + 506 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 267, + 288, + 506 + ], + "spans": [ + { + "bbox": [ + 46, + 267, + 288, + 506 + ], + "type": "text", + "content": "IMLTR poses significant challenges to IL approaches due to its unbalanced features. 1) At the dataset level, it is difficult to collect sufficient training data for minority languages such as Bangla compared to popular languages such as English and Chinese, which affects the quality of recognition models. 2) At the language level, the size of character sets varies from tens to thousands across different languages, which leads to data imbalance. 3) At the character level, the occurrence frequency of characters follows a long-tailed distribution, leading to class imbalance. In addition, IMLTR faces the problem of variable length recognition, where text instances are the recognizing unit instead of character classes. Therefore, IL methods cannot sample characters as evenly as required in the context of IMLTR, resulting in a significant fraction of characters not being included in the rehearsal data, as shown in Fig. 2. This phenomenon is summarized as rehearsal-imbalance in Fig. 1. Rehearsal-imbalance leads to catastrophic forgetting, where forgotten characters cannot be recognized. Therefore, there is an urgent need to develop new methods to overcome it." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 509, + 287, + 675 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 509, + 287, + 675 + ], + "spans": [ + { + "bbox": [ + 46, + 509, + 287, + 675 + ], + "type": "text", + "content": "Although the rehearsal set does not ensure full coverage of all interlingual character classes, it is still adequate for training a language domain predictor to identify the languages. Motivated by this observation, we propose a novel Multiplexed Routing Network (MRN) for IMLTR. MRN involves training a new text recognition model at each learning step and utilizing it and previously trained models for parallel feature extraction. A domain MLP router is designed to receive these features and predict the probability over the languages. Meanwhile, these features are used for character recognition in their own domain by feeding them to the multi-lingual modeling module. Finally, we fuse the results obtained at both the language domain and character levels to decode the recognized character sequence." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 677, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 288, + 713 + ], + "type": "text", + "content": "Our contributions can be summarized as follows. First, we introduce the IMLTR task, the first effort to adapt IL to text recognition. It contributes to the exploration of other" + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 307, + 69, + 545, + 252 + ], + "blocks": [ + { + "bbox": [ + 307, + 69, + 545, + 252 + ], + "lines": [ + { + "bbox": [ + 307, + 69, + 545, + 252 + ], + "spans": [ + { + "bbox": [ + 307, + 69, + 545, + 252 + ], + "type": "image", + "image_path": "6eea735e36321ad4fa21db70179b554d3060043fd89f66eab236167296b745d9.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 255, + 547, + 299 + ], + "lines": [ + { + "bbox": [ + 305, + 255, + 547, + 299 + ], + "spans": [ + { + "bbox": [ + 305, + 255, + 547, + 299 + ], + "type": "text", + "content": "Figure 2. The showcase of rehearsal-imbalance. Data-imbalance (top) and class-imbalance (bottom) are severely aggravated from the full dataset to the rehearsal set, while the character classes to be read remain the same, making IMLTR particularly challenging." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 318, + 545, + 414 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 318, + 545, + 414 + ], + "spans": [ + { + "bbox": [ + 305, + 318, + 545, + 414 + ], + "type": "text", + "content": "practical scenarios for text recognition. Second, we develop MRN to address the rehearsal-imbalance problem in ILMTR. It is a dynamic and scalable architecture that is compatible with various IL methods and recognition models. Third, experiments on two benchmarks show that MRN significantly outperforms existing general-purpose IL methods, achieving accuracy improvements ranging from " + }, + { + "bbox": [ + 305, + 318, + 545, + 414 + ], + "type": "inline_equation", + "content": "10.3\\%" + }, + { + "bbox": [ + 305, + 318, + 545, + 414 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 305, + 318, + 545, + 414 + ], + "type": "inline_equation", + "content": "27.4\\%" + }, + { + "bbox": [ + 305, + 318, + 545, + 414 + ], + "type": "text", + "content": " under different settings." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 424, + 392, + 436 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 424, + 392, + 436 + ], + "spans": [ + { + "bbox": [ + 306, + 424, + 392, + 436 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 444, + 453, + 456 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 444, + 453, + 456 + ], + "spans": [ + { + "bbox": [ + 306, + 444, + 453, + 456 + ], + "type": "text", + "content": "2.1. Incremental Learning (IL)" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 462, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 462, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 462, + 545, + 713 + ], + "type": "text", + "content": "IL has received intensive research attention over the past few years. Typically, the problem is investigated in the context of image classification, where addressing catastrophic forgetting effectively and efficiently is its core issue. We can broadly classify existing efforts into three categories: regularization [30, 50, 15], rehearsal [36, 9, 1] and dynamic expansion [2, 46, 17, 28]. Regularization methods emphasize constraining weight changes, e.g., allowing only small magnitude changes from the previous weights. It suffers from the problem that the changes do not adequately describe the complex pattern shifts caused by new task learning. Rehearsal methods keep a small amount of old data when training a new task, thus retaining some prior knowledge. Studies in this category focus on the selection of old data and the way it is used. For example, iCaRL was developed to learn an exemplar-based data representation [37]. Alternatively, dynamic expansion methods dynamically create feature extraction sub-networks each associated with one specific task [23, 12, 45, 28]. Early methods required a task identifier to select the correct sub-network at test time. Unfortunately, the assumption is unrealistic as new sam" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "18645" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 71, + 545, + 313 + ], + "blocks": [ + { + "bbox": [ + 50, + 71, + 545, + 313 + ], + "lines": [ + { + "bbox": [ + 50, + 71, + 545, + 313 + ], + "spans": [ + { + "bbox": [ + 50, + 71, + 545, + 313 + ], + "type": "image", + "image_path": "f3c06cfdec4161fb03034253ada4f0c86080b4d294524060cd7509e0dd27f371.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 316, + 546, + 361 + ], + "lines": [ + { + "bbox": [ + 46, + 316, + 546, + 361 + ], + "spans": [ + { + "bbox": [ + 46, + 316, + 546, + 361 + ], + "type": "text", + "content": "Figure 3. An overview of MRN. In stage-I, text recognizers are trained language-by-language. While in stage-II, these recognizers are frozen for feature extraction. The Domain MLP Router, which is trained based on the rehearsal set, is proposed to predict the likelihood distribution over the languages. Meanwhile, a padded classification layer is constructed, where the parallel predicted text sequences and likelihood distributions are merged to generate the decoded character sequence." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 380, + 289, + 523 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 380, + 289, + 523 + ], + "spans": [ + { + "bbox": [ + 46, + 380, + 289, + 523 + ], + "type": "text", + "content": "plies would not come with their task identifiers. Recently, DER [46] proposed a dynamically expandable representation by discarding the task identifier, where the classifier was finetuned on a balanced exemplar subset to mitigate the task-tendency bias. It attained impressive results. Some recent works [7, 14] studied IL in inhomogeneous or uneven datasets. However, the datasets they adopted are still ideal and cannot sufficiently describe challenges in real-world problems. Moreover, there were also some studies proposed for object detection [21, 10, 48, 47], semantic segmentation [49, 16, 51] and object retrieval [32]. Text recognition has not been studied in IL so far." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 536, + 211, + 550 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 536, + 211, + 550 + ], + "spans": [ + { + "bbox": [ + 47, + 536, + 211, + 550 + ], + "type": "text", + "content": "2.2. Scene Text Recognition (STR)" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 556, + 287, + 652 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 556, + 287, + 652 + ], + "spans": [ + { + "bbox": [ + 46, + 556, + 287, + 652 + ], + "type": "text", + "content": "Text recognition is a longstanding research topic in computer vision and pattern recognition. Recent efforts mainly focused on recognizing text in natural scenes, i.e., STR. The task exhibits variations like text distortion, occlusion, blurring, etc., making the recognition challenging. With the advances in deep learning, especially CNN [5, 39, 26, 40] and Transformers [38, 20, 54, 43, 18, 44], STR methods have been pushed forward significantly." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "content": "Multilingual text recognition (MLTR) is an important sub-field of STR. The most popular solution for MLTR was data-joint training [35, 8, 34, 4], where all data was gathered to train a model capable of recognizing all character classes. However, in addition to computational inten" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 380, + 547, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 380, + 547, + 536 + ], + "spans": [ + { + "bbox": [ + 304, + 380, + 547, + 536 + ], + "type": "text", + "content": "sive, the approach also had the drawback of being biased toward data-rich languages, while performing poorly in minority languages where training data was scarce. As alternatives, multi-task or ensemble architectures were developed to allow data-rich languages to transfer knowledge to datapoor ones [6, 13]. They alleviated the data scarcity issue to some extent. In addition, Some studies [22, 24, 41, 29] added a script identification step to text recognition. They first identified the language domain and then selected the corresponding recognizer. Although similar to ours in the pipeline, they did not explore dependencies between languages. Moreover, none of them discussed the task within the IL framework." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 552, + 389, + 566 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 552, + 389, + 566 + ], + "spans": [ + { + "bbox": [ + 306, + 552, + 389, + 566 + ], + "type": "text", + "content": "3. Methodology" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 573, + 529, + 586 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 573, + 529, + 586 + ], + "spans": [ + { + "bbox": [ + 306, + 573, + 529, + 586 + ], + "type": "text", + "content": "3.1. Incremental Multilingual Text Recognition" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": "Our goal is to develop a unified model that can recognize text instances in different languages, with the model trained incrementally language-by-language. Mathematically, assume there are " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": " kinds of languages " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\{\\mathcal{D}_1,\\dots ,\\mathcal{D}_I\\}" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": ", with " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_i = \\left\\{(\\mathbf{x}_{i,1},y_{i,1}),\\dots ,(\\mathbf{x}_{i,N(i)},y_{i,N(i)})\\right\\}" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": " as the training data at step " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": " (i.e., task " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": "), where " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "x_{i,j}" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": " is the " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": "-th input image and " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "y_{i,j} \\in \\mathcal{C}_i" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": " is its label within the label set " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_i" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "N(i)" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": " is the number of samples in set " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_i" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": ". At the " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": "-th learning step, samples of the " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": "-th language will be added to the training set. Therefore, the goal can be formulated as to learn" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "18646" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": "new knowledge from the set " + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_i" + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": ", while retaining the previous knowledge learned from old data " + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "inline_equation", + "content": "\\{\\mathcal{D}_1, \\dots, \\mathcal{D}_{i-1}\\}" + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": ". The label space of the model is all seen categories " + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "inline_equation", + "content": "\\tilde{\\mathcal{C}}_i = \\cup_{k=1}^i \\mathcal{C}_k" + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": " and the model is expected to predict well on all classes in " + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "inline_equation", + "content": "\\tilde{\\mathcal{C}}_i" + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": ". Note that there may be a small overlap between label sets, i.e., " + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_k \\cap \\mathcal{C}_j \\neq \\emptyset" + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": " for some " + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": ". To better fight against catastrophic forgetting, we discuss IMLTR in the rehearsal setting. That is, a small and fix-sized rehearsal set " + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_i" + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": " with a portion of samples from " + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "inline_equation", + "content": "\\{\\mathcal{D}_1, \\dots, \\mathcal{D}_{i-1}\\}" + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": " is accessible at incremental step " + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 200, + 230, + 213 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 200, + 230, + 213 + ], + "spans": [ + { + "bbox": [ + 47, + 200, + 230, + 213 + ], + "type": "text", + "content": "3.2. Challenge and Solution Statement" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "spans": [ + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "content": "To build a recognition model to correctly recognize text instances from all currently seen languages and their character classes, let " + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "inline_equation", + "content": "x_{n}" + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "content": " be the text instance to be recognized. " + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "inline_equation", + "content": "y_{n}^{t} \\in \\tilde{\\mathcal{C}}_{i}" + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "content": " denotes the " + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "content": "-th character label corresponding to " + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "inline_equation", + "content": "x_{n}" + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "inline_equation", + "content": "T(n)" + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "content": " gives the total number of characters in this instance. IMLTR differs significantly from existing IL settings. For example compared to incremental image classification, standard IL usually has " + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "inline_equation", + "content": "|\\tilde{\\mathcal{C}}_i| \\leq 100" + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "inline_equation", + "content": "T(n) = 1" + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "content": " regardless of the value " + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "content": ". While the size of rehearsal set " + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_i" + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "content": " is a constant (e.g., 2,000). However, in IMLTR " + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_i" + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "content": " ranges from dozens of to thousands of character classes for different languages, and " + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "inline_equation", + "content": "T(n)" + }, + { + "bbox": [ + 46, + 218, + 289, + 457 + ], + "type": "text", + "content": " belongs to (1, 25), assuming 25 as the maximized length of a character sequence. Consequently, rehearsal-imbalance becomes a prominent challenge. Due to the limited size of the rehearsal set, it is not rare that a character class appears in the full dataset but is absent from the rehearsal set, as shown in Fig. 2. Thus, the incrementally trained models are likely to forget the absent character classes, despite having learned them previously, which can ultimately hurt the recognition accuracy." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 458, + 287, + 565 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 458, + 287, + 565 + ], + "spans": [ + { + "bbox": [ + 46, + 458, + 287, + 565 + ], + "type": "text", + "content": "Although the rehearsal set may not be enough to train a multilingual text recognizer to identify thousands of character classes, it is still sufficient to train a language classifier to recognize the language domains present in the text instance, whose classes are a much smaller number. Once the language domains are identified, we can choose an alternative scheme that involves aggregating the results from corresponding language recognizers to perform the recognition task, thereby bypassing the rehearsal-imbalance issue." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "spans": [ + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "text", + "content": "Motivated by this, we define " + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "inline_equation", + "content": "\\mathcal{H}_i" + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "inline_equation", + "content": "\\varphi_i" + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "text", + "content": " the skeleton network (all except classifier) and classifier trained at the " + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "text", + "content": "-th incremental step. Note that " + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "inline_equation", + "content": "\\mathcal{H}_i" + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "text", + "content": " is trained on " + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_i" + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "text", + "content": ", therefore can only recognize character classes of the " + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "text", + "content": "-th language in principle. Meanwhile, " + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "inline_equation", + "content": "\\varphi_i" + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "text", + "content": " is set to have " + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "inline_equation", + "content": "\\tilde{\\mathcal{C}}_i" + }, + { + "bbox": [ + 46, + 565, + 287, + 673 + ], + "type": "text", + "content": " nodes to be compatible with typical IL settings, despite not being taught to recognize character classes of other languages. Then, we can adopt an aggregating-like scheme to implement IMLTR. The learning function can be written as:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 83, + 681, + 287, + 716 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 83, + 681, + 287, + 716 + ], + "spans": [ + { + "bbox": [ + 83, + 681, + 287, + 716 + ], + "type": "interline_equation", + "content": "\\sum_ {k = 1} ^ {i} \\prod_ {t = 1} ^ {T (n)} \\left(P \\left(y _ {n} ^ {t} \\mid x _ {n}; \\mathcal {H} _ {k}, \\varphi_ {k}\\right) * S \\left(d _ {n} ^ {k}\\right)\\right), \\tag {1}", + "image_path": "58b8226615f552e43a4d4a9b979cdab910805aaa1dc0d7bfa46bbbeb3291c213.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 72, + 547, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 156 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 156 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 72, + 547, + 156 + ], + "type": "inline_equation", + "content": "d_n^k" + }, + { + "bbox": [ + 304, + 72, + 547, + 156 + ], + "type": "text", + "content": " is the domain score indicating " + }, + { + "bbox": [ + 304, + 72, + 547, + 156 + ], + "type": "inline_equation", + "content": "x_{n}" + }, + { + "bbox": [ + 304, + 72, + 547, + 156 + ], + "type": "text", + "content": " being classified as the " + }, + { + "bbox": [ + 304, + 72, + 547, + 156 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 304, + 72, + 547, + 156 + ], + "type": "text", + "content": "-th language. " + }, + { + "bbox": [ + 304, + 72, + 547, + 156 + ], + "type": "inline_equation", + "content": "S(\\cdot)" + }, + { + "bbox": [ + 304, + 72, + 547, + 156 + ], + "type": "text", + "content": " is the score quantization function, which can be a one-hot vector (hard-voting) or a likelihood distribution (soft-voting). Eq. 1 treats IMLTR as a weighted ensemble of recognition models trained based on different languages. By doing so, it successfully overcomes the rehearsal-imbalance issue within the IL framework." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 164, + 413, + 176 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 164, + 413, + 176 + ], + "spans": [ + { + "bbox": [ + 306, + 164, + 413, + 176 + ], + "type": "text", + "content": "3.3. Method Overview" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "spans": [ + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "text", + "content": "We propose a Multiplexed Routing Network (MRN) to implement this idea. As illustrated by Fig. 3, it contains two stages, i.e., individual language modeling (stage-I) and multi-lingual modeling (stage-II). In stage-I, given " + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_i" + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "text", + "content": " for the " + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "text", + "content": "-th language, we train its recognizer using a popular text recognition model, which can recognize the character classes seen in " + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_i" + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "text", + "content": ". The model is represented as " + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "inline_equation", + "content": "\\mathcal{H}_i" + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "inline_equation", + "content": "\\varphi_i" + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "text", + "content": ". For character classes in " + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "inline_equation", + "content": "\\tilde{\\mathcal{C}}_i" + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "text", + "content": " but not in " + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_i" + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "text", + "content": ", we simply truncate gradient propagation from these nodes thus the learned model still focuses on recognizing the " + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 183, + 547, + 302 + ], + "type": "text", + "content": "-th language." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "spans": [ + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "type": "text", + "content": "Stage-II aims at building a multilingual routing network for IMLTR. Given a text instance " + }, + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "type": "inline_equation", + "content": "x_{n} \\in \\mathcal{D}_{i} \\cup \\mathcal{M}_{i}" + }, + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "type": "text", + "content": ", we feed it into all the learned " + }, + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "type": "text", + "content": " skeleton networks in parallel, while keeping the parameters of the networks frozen for targeted feature extraction. It extracts " + }, + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "type": "text", + "content": " sets of features, each associated with a certain language. The features are further fed into a Domain MLP Router (DM-Router) module, which is designed for domain score estimation, i.e., estimating the likelihood that the text instance belongs to the languages. Meanwhile, the " + }, + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "type": "text", + "content": " sets of features are fed to their respective classifiers, where the corresponding recognition character sequences are obtained. To merge their recognition, we pad the classification nodes with zeros to " + }, + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "type": "inline_equation", + "content": "|\\tilde{\\mathcal{C}}_i|" + }, + { + "bbox": [ + 304, + 304, + 547, + 542 + ], + "type": "text", + "content": ", ensuring that all classifiers are aligned to the same dimension. As a result, their recognized characters can be merged using weighted element-wise addition, where the weights are the domain scores estimated using DM-Router. Finally, the recognition is conducted by applying a CTC- or attention-based decoding. Since DM-Router plays a critical role in the proposed method, we provide a detailed illustration below." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 551, + 429, + 562 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 551, + 429, + 562 + ], + "spans": [ + { + "bbox": [ + 306, + 551, + 429, + 562 + ], + "type": "text", + "content": "3.4. Domain MLP Router" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 570, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 547, + 713 + ], + "type": "text", + "content": "DM-Router uses features that are biased towards different language domains to discriminate the language domain of text instances. It accomplishes this by leveraging both the rehearsal set and the language data that arrives at the " + }, + { + "bbox": [ + 304, + 570, + 547, + 713 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 570, + 547, + 713 + ], + "type": "text", + "content": "-th step. While training a separate single-network classifier, which takes an image as input and outputs the language domain scores, can identify the language domains, we believe that this approach overlooks inter-domain dependencies that could be explored for better identification. For instance, different languages may have distinct appearance patterns, such as strokes, which differ significantly between Eastern Asian languages and Latin. Additionally, their features ex" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "18647" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 48, + 70, + 289, + 228 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 289, + 228 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 289, + 228 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 289, + 228 + ], + "type": "image", + "image_path": "5c56d96ed465594d9facb88afea3ddac6cd2695f29f26483ee5717e0268a24e3.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 230, + 287, + 264 + ], + "lines": [ + { + "bbox": [ + 46, + 230, + 287, + 264 + ], + "spans": [ + { + "bbox": [ + 46, + 230, + 287, + 264 + ], + "type": "text", + "content": "Figure 4. Detail structure of Domain MLP Router (DM-Router). Spatial-domain and Channel-domain dependencies are explored and fused to generate the language domain score distribution." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 289, + 287, + 313 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 289, + 287, + 313 + ], + "spans": [ + { + "bbox": [ + 46, + 289, + 287, + 313 + ], + "type": "text", + "content": "hibit different frequency distributions, which can also aid language identification." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "spans": [ + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "text", + "content": "To achieve this goal, DM-Router accepts all " + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "text", + "content": " sets of features extracted previously as input and mines the spatial-domain and channel-domain dependencies for better language identification. The detailed structure of DM-Router is shown in Fig. 4. Features from different skeleton networks are concatenated, generating a feature cubic with size " + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "inline_equation", + "content": "P \\times D \\times C" + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "text", + "content": " stand for the number of reshaped spatial patches, language domains, and feature channels, respectively. Then, a linear projection is applied along the channel dimension (C Proj), followed by reshaping the cubic from the patch-domain dimension. Next, a gated-mechanism is followed to generate the attention scores between the patch and domain. This is achieved by applying linear projection along the patch-domain dimension, followed by a layer norm and a feature dot product. We reshape the generated feature back to a feature cubic of the same size and merge it with the original cubic. The operations above explore the spatial-domain dependency. A similar operation is then applied to the merged feature cubic to explore the channel-domain dependence. In the following, the explored feature cubic gradually shrinks to a " + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 46, + 316, + 289, + 602 + ], + "type": "text", + "content": "-dimensional score vector that indicates the probability over the languages. It represents the likelihood of each language domain for the input text instance." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 605, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 287, + 715 + ], + "type": "text", + "content": "DM-Router is an MLP-based attention network that targets language domain weighting. Note that there are a few similar solutions in the literature. Expert Gate (E-Gate) [2] developed an expert gating network that identified which model could be employed based on image reconstruction loss. However, it might not effectively discriminate IMLTR due to some languages exhibiting character class overlapping, which can cause classification confusion. On the other hand, multilingual OCR [29] determines the languages by" + } + ] + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 309, + 71, + 545, + 135 + ], + "blocks": [ + { + "bbox": [ + 309, + 71, + 545, + 135 + ], + "lines": [ + { + "bbox": [ + 309, + 71, + 545, + 135 + ], + "spans": [ + { + "bbox": [ + 309, + 71, + 545, + 135 + ], + "type": "table", + "html": "
DatasetcategoriesTask1Task2Task3Task4Task5Task6
ChineseLatinJapaneseKoreanArabicBangla
MLT17[35]train instance2687474114609563137113237
test instance5291107313501230983713
train class18953251620112473112
MLT19[34]train instance2897529215324610742303542
test instance3225882590679470393
train class20862201728116073102
", + "image_path": "b412bbc75944f53887c670c22f92a3c7835f18ecbb24adc7d7ae779b59a406f2.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "bbox": [ + 320, + 142, + 531, + 152 + ], + "lines": [ + { + "bbox": [ + 320, + 142, + 531, + 152 + ], + "spans": [ + { + "bbox": [ + 320, + 142, + 531, + 152 + ], + "type": "text", + "content": "Table 1. MLT17 and MLT19 statistics in our experiments." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 305, + 171, + 545, + 243 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 171, + 545, + 243 + ], + "spans": [ + { + "bbox": [ + 305, + 171, + 545, + 243 + ], + "type": "text", + "content": "script recognition and selected the corresponding model for recognition. Unlike these hard-voting methods, MRN employs soft-voting, which allows for the use of knowledge from other languages. For instance, Japanese has the ability to correct Chinese to some extent, given that they share some common words and similar strokes." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 249, + 394, + 262 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 249, + 394, + 262 + ], + "spans": [ + { + "bbox": [ + 306, + 249, + 394, + 262 + ], + "type": "text", + "content": "3.5. Training Loss" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 268, + 545, + 303 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 268, + 545, + 303 + ], + "spans": [ + { + "bbox": [ + 305, + 268, + 545, + 303 + ], + "type": "text", + "content": "MRN has two loss terms. One for multilingual text recognition while the other for language domain prediction. The total loss function is written as:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 370, + 311, + 545, + 323 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 370, + 311, + 545, + 323 + ], + "spans": [ + { + "bbox": [ + 370, + 311, + 545, + 323 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\mathrm {c l f}} + \\alpha \\mathcal {L} _ {\\text {d o m a i n}}, \\tag {2}", + "image_path": "62829b8e1894b9e608a09df74f5d1aadf7e29a859d60378e6247adea00b9e296.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 331, + 545, + 342 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 331, + 545, + 342 + ], + "spans": [ + { + "bbox": [ + 305, + 331, + 545, + 342 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 331, + 545, + 342 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 305, + 331, + 545, + 342 + ], + "type": "text", + "content": " is an empirical hyperparameter to balance the two." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 343, + 545, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 343, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 304, + 343, + 545, + 498 + ], + "type": "text", + "content": "MRN shows two advantages in dealing with rehearsal-imbalance. First, it ensures fair use of language. As previously mentioned, data distribution is uneven across different languages, and if not addressed during model training, it may lead to bias in the resulting model. By adopting language-by-language training and parameter freezing, data-rich and data-poor languages are treated equally, and class-imbalance is also alleviated. Second, MRN makes use of inter-lingual dependency in two ways: through the DM-Router described earlier, and through recognition score merging. When a character is recognized by more than one language, it receives confidence scores from each of them, allowing for the utilization of inter-lingual dependencies." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 508, + 388, + 521 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 508, + 388, + 521 + ], + "spans": [ + { + "bbox": [ + 306, + 508, + 388, + 521 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 528, + 501, + 540 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 528, + 501, + 540 + ], + "spans": [ + { + "bbox": [ + 306, + 528, + 501, + 540 + ], + "type": "text", + "content": "4.1. Datasets and Implementation Details" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "text", + "content": "ICDAR 2017 MLT (MLT17) [35] has 68,613 training instances and 16,255 validation instances, which are from 6 scripts and 9 languages: Chinese, Japanese, Korean, Bangla, Arabic, Italian, English, French, and German. The last four use Latin script. The samples are from natural scenes with challenges like blur, occlusion, and distortion. We use the validation set for test due to the unavailability of test data. Tasks are split by scripts and modeled sequentially. Special symbols are discarded at the preprocessing step as with no linguistic meaning." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "ICDAR 2019 MLT (MLT19) [34] has 89,177 text instances coming from 7 scripts. Since the inaccessibility of test set, we randomly split the training instances to 9:1 script-by-script, for model training and test. To be consistent with" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "18648" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 62, + 69, + 531, + 383 + ], + "blocks": [ + { + "bbox": [ + 62, + 69, + 531, + 383 + ], + "lines": [ + { + "bbox": [ + 62, + 69, + 531, + 383 + ], + "spans": [ + { + "bbox": [ + 62, + 69, + 531, + 383 + ], + "type": "table", + "html": "
MLT17MLT19
Model: CRNN (TPAMI'17) [39]
T1T2T3T4T5T6AVGT1T2T3T4T5T6AVG
Bound------92.1------84.9
Baseline91.151.751.037.229.322.347.185.149.646.535.527.620.744.2
LwF (TPAMI'17)[31]91.153.753.438.229.723.748.385.151.649.236.527.722.045.3
EWC (PNAS'17)[30]91.156.550.437.230.521.547.985.155.546.335.828.819.945.2
WA (CVPR'20) [52]91.154.648.738.228.523.147.485.152.244.336.726.821.644.4
DER (CVPR'21)[46]91.176.355.846.439.335.857.585.175.240.445.136.634.252.8
MRN91.188.677.273.769.869.878.485.185.173.268.365.365.573.7
Model: TRBA (ICCV'19) [3]
T1T2T3T4T5T6AVGT1T2T3T4T5T6AVG
Bound------94.9------90.5
Baseline91.349.647.336.128.624.046.185.449.444.034.827.423.144.0
LwF (TPAMI'17)[31]91.355.738.828.722.618.742.685.454.235.027.220.517.039.9
EWC (PNAS'17)[30]91.350.443.633.125.621.944.385.449.440.631.724.820.642.1
WA (CVPR'20) [52]91.345.441.830.723.519.642.185.444.037.929.221.618.139.4
DER (CVPR'21)[46]91.360.153.038.831.428.650.585.460.750.337.230.328.148.7
MRN91.387.975.872.271.568.777.985.484.573.267.866.764.873.7
Model: SVTR-Base (IJCAI'22) [18]
T1T2T3T4T5T6AVGT1T2T3T4T5T6AVG
Bound------90.1------83.2
Baseline90.632.540.530.824.519.939.884.831.337.029.222.619.137.3
LwF (TPAMI'17)[31]90.628.038.429.924.118.338.284.827.034.628.422.317.035.7
EWC (PNAS'17)[30]90.633.041.231.124.620.040.184.831.337.729.522.619.037.5
WA (CVPR'20) [52]90.628.037.930.424.819.838.684.826.734.628.322.618.635.9
DER (CVPR'21)[46]90.674.555.755.049.545.761.884.871.652.952.246.643.658.6
MRN90.686.473.965.663.458.173.084.883.769.464.457.853.168.9
", + "image_path": "35885533769ba6c3cd038ea568353d9bb0c12550006ae9af2e6b51ca9733ccff.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 392, + 545, + 415 + ], + "lines": [ + { + "bbox": [ + 46, + 392, + 545, + 415 + ], + "spans": [ + { + "bbox": [ + 46, + 392, + 545, + 415 + ], + "type": "text", + "content": "Table 2. Accuracy (%) of different text recognizers and incremental learning methods on MLT17 and MLT19. Baseline denotes the model trained solely based on the rehearsal set and language data arrived at that step. The language incremental order is introduced in Sec. 4.1." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 434, + 287, + 457 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 434, + 287, + 457 + ], + "spans": [ + { + "bbox": [ + 46, + 434, + 287, + 457 + ], + "type": "text", + "content": "MLT2017 dataset, we discard the Hindi script and also special symbols. Statistics of the two datasets are shown Tab. 1." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 458, + 287, + 625 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 458, + 287, + 625 + ], + "spans": [ + { + "bbox": [ + 46, + 458, + 287, + 625 + ], + "type": "text", + "content": "Height and width of the images are scaled uniformly to " + }, + { + "bbox": [ + 46, + 458, + 287, + 625 + ], + "type": "inline_equation", + "content": "32 \\times 256" + }, + { + "bbox": [ + 46, + 458, + 287, + 625 + ], + "type": "text", + "content": ". The maximum length of a character sequence is set to 25. All models, each corresponding to a language domain, are trained with 10,000 iterations, using the Adam optimizer and the one-cycle learning rate scheduler [42] with a maximum learning rate of 0.0005. The batch size is set to 256. To mitigate the dataset variance, in each batch we evenly sample training samples from both datasets, that is, half from MLT17 and half from MLT19. A random order for the six languages is employed, which is Chinese, Latin, Japanese, Korean, Arabic, Bangla. Other orders will be discussed later. For the rehearsal setting, we limit the rehearsal size to 2000 samples unless specified. We conduct the experiments using two NVIDIA RTX 3090 GPUs." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 635, + 236, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 635, + 236, + 647 + ], + "spans": [ + { + "bbox": [ + 47, + 635, + 236, + 647 + ], + "type": "text", + "content": "4.2. Comparison with Existing Methods" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 654, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 654, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 654, + 288, + 713 + ], + "type": "text", + "content": "We equip MRN with different text recognizers and combine them with different IL methods. Specifically, we consider three typical STR schemes: CTC-based (CRNN [39]), attention-based (TRBA [3]), and ViT-based (SVTR [18]). Meanwhile, four popular IL methods are chosen, i.e., Lwf" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 434, + 545, + 470 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 434, + 545, + 470 + ], + "spans": [ + { + "bbox": [ + 305, + 434, + 545, + 470 + ], + "type": "text", + "content": "[31], EWC [30], WA [52] and DER [46]. All models retain their original settings, except for the removal of the auxiliary loss of DER, which reduces its performance in our task." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 474, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 474, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 474, + 546, + 713 + ], + "type": "text", + "content": "In Tab. 2, we give the results at different incremental steps, where the language is added one-by-one and the average accuracy of different methods is reported. Bound, the model trained using all training data, is also listed as the oracle for reference. As can be seen, MRN consistently outperforms all the compared methods by significant margins under different settings, no matter which recognizer is employed. When looking into the general-purpose IL methods, their accuracy mostly decreased rapidly as the incremental steps due to the affection of rehearsal-imbalance. DER has the highest accuracy among them, as its dynamic expansion architecture has certain advantages in fighting against catastrophic forgetting. However, there is still a clear accuracy gap between DER and our MRN, and the gap widens as the incremental step increases. We attribute the accuracy improvement achieved by MRN to two factors. First, IMLTR is a task that differs significantly from image classification, where most IL methods have been experimented on. These methods do not well accommodate the challenge raised by IMLTR. For example, the rehearsal-imbalance issue. Sec-" + } + ] + } + ], + "index": 7 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "text", + "content": "18649" + } + ] + } + ], + "index": 8 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": "ond, MRN develops an elegant pipeline that implements the recognition in a domain routing and result fusion manner. It works particularly well for scenarios where incremental tasks exhibit significant differences." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 120, + 288, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 120, + 288, + 228 + ], + "spans": [ + { + "bbox": [ + 46, + 120, + 288, + 228 + ], + "type": "text", + "content": "When comparing the recognizers, MRN equipped with CRNN has the highest overall accuracy. The result is interesting as CRNN has a simpler architecture and generally performs worse than the other two methods on typical STR tasks. We attribute this to parameter freezing, where the feature extraction backbone (e.g., " + }, + { + "bbox": [ + 46, + 120, + 288, + 228 + ], + "type": "inline_equation", + "content": "\\mathcal{H}_i" + }, + { + "bbox": [ + 46, + 120, + 288, + 228 + ], + "type": "text", + "content": ") and the decoder cannot be jointly optimized. Therefore, advanced models are more severely affected, while the simpler one is less affected and can better mitigate catastrophic forgetting." + } + ] + } + ], + "index": 1 + }, + { + "type": "table", + "bbox": [ + 71, + 236, + 264, + 335 + ], + "blocks": [ + { + "bbox": [ + 71, + 236, + 264, + 335 + ], + "lines": [ + { + "bbox": [ + 71, + 236, + 264, + 335 + ], + "spans": [ + { + "bbox": [ + 71, + 236, + 264, + 335 + ], + "type": "table", + "html": "
modelMLT17MLT19
AvgLastAvgLast
None64.837.960.835.6
MLP68.560.565.356.3
CycleMLP[11]75.563.571.160.0
ViP[25]76.462.672.259.6
gMLP[33]77.568.273.164.2
DM-Router78.469.873.865.5
", + "image_path": "2b190f3573e2727922f90ede742c2bd3480c73f3483c0b310c95a2c42762ca18.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 372, + 141, + 385 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 372, + 141, + 385 + ], + "spans": [ + { + "bbox": [ + 47, + 372, + 141, + 385 + ], + "type": "text", + "content": "4.3. Ablation Study" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 391, + 287, + 426 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 391, + 287, + 426 + ], + "spans": [ + { + "bbox": [ + 46, + 391, + 287, + 426 + ], + "type": "text", + "content": "We perform a series of controlled experiments to gain a deeper understanding of MRN. CRNN is employed as the text recognizer unless specified." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 426, + 288, + 582 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 426, + 288, + 582 + ], + "spans": [ + { + "bbox": [ + 46, + 426, + 288, + 582 + ], + "type": "text", + "content": "Effectiveness of DM-Router: There are multiple ways to deduce the language domain scores. We enumerate several of them that have been used in existing studies, as shown in Tab. 3. None denotes no dependence is explored, which corresponds to the worst result. It, in turn, demonstrates the necessity of utilizing language dependence. Among the rest competitors, MLP enables a naive learning mechanism while the remaining three are based on more advanced MLP-like models, which are typically more effective. Despite this, DM-Router attains the highest accuracy among the methods. The results clearly demonstrate the rationality of the DM-Router structure in terms of language dependence exploration." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": "Influence of the size of the rehearsal set: We conduct analytical experiments to evaluate the influence of the rehearsal size on the accuracy of Lwf [31], DER [46] and MRN. Fig. 4 shows the accuracy under different rehearsal sizes. As anticipated, increasing the rehearsal set size leads to accuracy gains, as more past memories are retained. We observe that larger gains are obtained in LwF and DER, particularly DER. This reveals the accuracy of general-purpose IL methods is largely affected by the rehearsal size in IMLTR, while MRN is less affected. MRN has already achieved relatively high accuracy, and the performance of MRN in iden" + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 332, + 70, + 523, + 200 + ], + "blocks": [ + { + "bbox": [ + 47, + 343, + 272, + 354 + ], + "lines": [ + { + "bbox": [ + 47, + 343, + 272, + 354 + ], + "spans": [ + { + "bbox": [ + 47, + 343, + 272, + 354 + ], + "type": "text", + "content": "Table 3. Performance comparisons on different MLP models." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 332, + 70, + 523, + 200 + ], + "lines": [ + { + "bbox": [ + 332, + 70, + 523, + 200 + ], + "spans": [ + { + "bbox": [ + 332, + 70, + 523, + 200 + ], + "type": "table", + "html": "
SizeMethodMLT17MLT19
AvgLastAvgLast
2kLwF[31]48.323.745.422.0
DER[46]57.535.852.834.2
MRN78.469.873.865.5
3kLwF[31]52.224.948.823.6
DER[46]60.942.058.740.6
MRN80.272.775.468.2
4kLwF[31]55.527.552.226.1
DER[46]66.448.763.846.6
MRN81.575.076.570.6
", + "image_path": "fc2a52468ad5aa5957151ca4830e92b91d3aa80f70bb6abbf3537f9590cc32b4.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 324, + 228, + 528, + 365 + ], + "blocks": [ + { + "bbox": [ + 326, + 208, + 525, + 219 + ], + "lines": [ + { + "bbox": [ + 326, + 208, + 525, + 219 + ], + "spans": [ + { + "bbox": [ + 326, + 208, + 525, + 219 + ], + "type": "text", + "content": "Table 4. Ablation study on the size of the rehearsal set." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 324, + 228, + 528, + 365 + ], + "lines": [ + { + "bbox": [ + 324, + 228, + 528, + 365 + ], + "spans": [ + { + "bbox": [ + 324, + 228, + 528, + 365 + ], + "type": "table", + "html": "
OrderMethodMLT17MLT19
AvgLastAvgLast
O1LwF[31]48.323.745.422.0
DER[46]57.535.852.834.2
MRN78.469.873.865.5
O2LwF[31]46.923.843.122.9
DER[46]63.139.158.739.6
MRN80.565.374.161.5
O3LwF[31]57.734.755.734.2
DER[46]69.641.365.738.2
MRN82.970.678.366.0
", + "image_path": "2f94bdf97610a43f677b5e633727dff786c03ea73552d1945b36158b15c857aa.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 323, + 394, + 529, + 471 + ], + "blocks": [ + { + "bbox": [ + 348, + 373, + 504, + 384 + ], + "lines": [ + { + "bbox": [ + 348, + 373, + 504, + 384 + ], + "spans": [ + { + "bbox": [ + 348, + 373, + 504, + 384 + ], + "type": "text", + "content": "Table 5. Ablation study on language order." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 323, + 394, + 529, + 471 + ], + "lines": [ + { + "bbox": [ + 323, + 394, + 529, + 471 + ], + "spans": [ + { + "bbox": [ + 323, + 394, + 529, + 471 + ], + "type": "table", + "html": "
Sampling StrategyMLT17MLT19
AvgLastAvgLast
Confidence56.443.854.041.2
Length71.050.366.648.9
Frequency72.656.667.853.7
Random78.469.873.865.5
", + "image_path": "865305e745df1dfe3f43685416fcb388c835b507d4303acbcd4231502c19f30f.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_body" + } + ], + "index": 12 + }, + { + "bbox": [ + 325, + 478, + 526, + 490 + ], + "lines": [ + { + "bbox": [ + 325, + 478, + 526, + 490 + ], + "spans": [ + { + "bbox": [ + 325, + 478, + 526, + 490 + ], + "type": "text", + "content": "Table 6. Ablation study on rehearsal sampling strategy." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 509, + 545, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 509, + 545, + 544 + ], + "spans": [ + { + "bbox": [ + 304, + 509, + 545, + 544 + ], + "type": "text", + "content": "tifying language domains is less affected by the rehearsal size. The results indicate that MRN is robust to rehearsal scarcity and can better fight against data imbalance." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 545, + 545, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 545, + 545, + 640 + ], + "spans": [ + { + "bbox": [ + 304, + 545, + 545, + 640 + ], + "type": "text", + "content": "Influence of language incremental order: In addition to the order in Sec. 4.1 (O1), we assess two other orders as follows: 1) Arabic, Chinese, Latin, Japanese, Bangla, Korean (O2); 2) Latin, Arabic, Bangla, Chinese, Japanese, Korean (O3). The two orders either alternate the three Eastern Asia languages, which have large vocabularies and show more stroke commonalities, or group them together at the end. We also include Lwf and DER for comparison." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": "Tab. 5 gives the results and two observations. First, O3 shows the best accuracy, while O2 also performs better than O1. It is because the three Eastern Asia languages are more difficult to recognize due to their large vocabulary sizes, therefore introducing them later leads to a better average accuracy. Meanwhile, putting them together also reduces the" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "18650" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 100, + 70, + 497, + 160 + ], + "blocks": [ + { + "bbox": [ + 100, + 70, + 497, + 160 + ], + "lines": [ + { + "bbox": [ + 100, + 70, + 497, + 160 + ], + "spans": [ + { + "bbox": [ + 100, + 70, + 497, + 160 + ], + "type": "table", + "html": "
MethodSelectModelVotingMLT17MLT19Params (M)FLOPs (G)
AvgLastAvgLast
Baseline---47.122.344.220.79.53.5
DER[46]---57.535.852.834.233.812.3
E-Gate[2]Re-Const.AutoencoderHard37.215.234.814.232.512.2
E-Gate[2]StackingAutoencoderHard62.715.259.314.235.512.4
MRNStackingDM-RouterHard74.462.969.957.733.512.4
MRNStackingDM-RouterSoft78.469.873.865.533.512.4
", + "image_path": "d625bc6d5dcd55ea01f31d80914b8b9abfa7ce40b4550e628e7a918c7ad9592d.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 200, + 167, + 392, + 179 + ], + "lines": [ + { + "bbox": [ + 200, + 167, + 392, + 179 + ], + "spans": [ + { + "bbox": [ + 200, + 167, + 392, + 179 + ], + "type": "text", + "content": "Table 7. Comparisons on different routing strategies." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 198, + 287, + 305 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 198, + 287, + 305 + ], + "spans": [ + { + "bbox": [ + 46, + 198, + 287, + 305 + ], + "type": "text", + "content": "oscillation during parameter learning and generates a better model, due to their stroke commonalities. The experiment suggests that careful selection of the order of languages can attain better accuracy. Second, O1 shows the largest accuracy gaps between MRN and other methods. This is because in O1, the large vocabulary languages appear earlier, while the rehearsal set is fix-sized, resulting in the most severe class imbalance among the three orders. The result indicates that MRN can better handle class imbalance." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 306, + 288, + 509 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 306, + 288, + 509 + ], + "spans": [ + { + "bbox": [ + 46, + 306, + 288, + 509 + ], + "type": "text", + "content": "Influence of rehearsal sampling strategy: The determination of text instances being sampled to the rehearsal set is an issue also worthy of abulating. Tab. 6 gives the accuracy of four sampling strategies, i.e., Confidence that selects instances with the highest recognition scores, Length that selects instances with the largest number of characters, Frequency that selects instances with the most frequently occurred characters, and Random adopted in our MRN that randomly selects the instances. Interestingly, Random gives the best accuracy. We attribute the reason to: the rehearsal set obtained from Confidence or Frequency cannot fully represent the true data distribution, where difficult or less occurred instances are excluded. Length, to some extent, overlooks the varying-length characteristic of IMLTR. On the contrary, Random, despite simple, well mimics the underlying data distribution and well handles the variable length challenge." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 510, + 288, + 643 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 510, + 288, + 643 + ], + "spans": [ + { + "bbox": [ + 46, + 510, + 288, + 643 + ], + "type": "text", + "content": "Comparison on routing strategy: We compare MRN with E-Gate and its variants. E-Gate [2] treats different subnetworks as experts, and each time selects the most appropriate one for inference. In Tab. 7 we provide the model details. Raw E-Gate performs poorly in IMLTR. When stacking is used to build feature extractors, the accuracy improves significantly and outperforms DER. We also evaluate MRN with hard-voting. It reports a worse result. Compared to other routing strategies, our MRN shows clear superiority in terms of accuracy, while incurring only a negligible cost in parameters and computational complexity." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 647, + 201, + 659 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 647, + 201, + 659 + ], + "spans": [ + { + "bbox": [ + 47, + 647, + 201, + 659 + ], + "type": "text", + "content": "4.4. Qualitative Results Analysis" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "content": "Fig. 5 gives several recognition results of MRN. It correctly read instances of different languages, even with the presence of common recognition difficulties. More importantly, MRN also recognizes character classes that are not" + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 315, + 198, + 538, + 352 + ], + "blocks": [ + { + "bbox": [ + 315, + 198, + 538, + 352 + ], + "lines": [ + { + "bbox": [ + 315, + 198, + 538, + 352 + ], + "spans": [ + { + "bbox": [ + 315, + 198, + 538, + 352 + ], + "type": "image", + "image_path": "a5ec3628cc6be67d97e1f80b18bad2db4fc01b96eb6ed3e3c4933d976f9731a3.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 354, + 545, + 375 + ], + "lines": [ + { + "bbox": [ + 305, + 354, + 545, + 375 + ], + "spans": [ + { + "bbox": [ + 305, + 354, + 545, + 375 + ], + "type": "text", + "content": "Figure 5. Illustrative recognition examples, where red denotes characters that are absent from the rehearsal set." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 396, + 545, + 431 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 396, + 545, + 431 + ], + "spans": [ + { + "bbox": [ + 305, + 396, + 545, + 431 + ], + "type": "text", + "content": "present in the rehearsal set. These results again demonstrate that our MRN is effective in handling rehearsal-imbalance and can generalize well to unseen character classes." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 444, + 379, + 456 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 444, + 379, + 456 + ], + "spans": [ + { + "bbox": [ + 306, + 444, + 379, + 456 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 465, + 545, + 657 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 465, + 545, + 657 + ], + "spans": [ + { + "bbox": [ + 304, + 465, + 545, + 657 + ], + "type": "text", + "content": "In this work, we introduce a new task called incremental multilingual text recognition (IMLTR). IMLTR handles text recognition in an incremental learning setting, therefore is suitable for applications like streaming data processing. IMLTR faces a distinct problem of rehearsal-imbalance, including data imbalance, class imbalance, and variable character length. To address this challenge, we designed a Multiplexed Routing Network (MRN) that first trains a multi-language correlated DM-router to weight the language domains, and then votes the separately trained recognition branches for final text recognition. Experiments on public benchmarks show that MRN significantly outperforms existing general-purpose IL methods by large margins. As the first attempt to apply IL to multilingual text recognition, we hope that this work will broaden the applications of text recognition and inspire further research in this area." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 665, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 665, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 665, + 545, + 713 + ], + "type": "text", + "content": "Acknowledgments This project was supported by National Key R&D Program of China (No. 2022YFB3104703) and in part by the National Natural Science Foundation of China (No. 62172103)" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "18651" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 134 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 134 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 134 + ], + "type": "text", + "content": "[1] Rahaf Aljundi, Francesca Babiloni, Mohamed Elhoseiny, Marcus Rohrbach, and Tinne Tuytelaars. Memory aware synapses: Learning what (not) to forget. In ECCV, pages 139-154, 2018. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 137, + 287, + 169 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 137, + 287, + 169 + ], + "spans": [ + { + "bbox": [ + 53, + 137, + 287, + 169 + ], + "type": "text", + "content": "[2] Rahaf Aljundi, Punarjay Chakravarty, and Tinne Tuytelaars. Expert gate: Lifelong learning with a network of experts. In CVPR, July 2017. 2, 5, 8" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 171, + 287, + 225 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 171, + 287, + 225 + ], + "spans": [ + { + "bbox": [ + 53, + 171, + 287, + 225 + ], + "type": "text", + "content": "[3] Jeonghun Baek, Geewook Kim, Junyeop Lee, Sungrae Park, Dongyoon Han, Sangdoo Yun, Seong Joon Oh, and Hwalsuk Lee. What is wrong with scene text recognition model comparisons? dataset and model analysis. In ICCV, pages 4714-4722, 2019. 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 228, + 287, + 271 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 228, + 287, + 271 + ], + "spans": [ + { + "bbox": [ + 53, + 228, + 287, + 271 + ], + "type": "text", + "content": "[4] Youngmin Baek, Seung Shin, Jeonghun Baek, Sungrae Park, Junyeop Lee, Daehyun Nam, and Hwalsuk Lee. Character region attention for text spotting. In ECCV, pages 504-521. Springer, 2020. 1, 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 273, + 287, + 327 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 273, + 287, + 327 + ], + "spans": [ + { + "bbox": [ + 53, + 273, + 287, + 327 + ], + "type": "text", + "content": "[5] Jinfeng Bai, Zhineng Chen, Bailan Feng, and Bo Xu. Chinese image text recognition on grayscale pixels. In 2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), pages 1380-1384. IEEE, 2014. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 329, + 287, + 384 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 329, + 287, + 384 + ], + "spans": [ + { + "bbox": [ + 53, + 329, + 287, + 384 + ], + "type": "text", + "content": "[6] Jinfeng Bai, Zhineng Chen, Bailan Feng, and Bo Xu. Image character recognition using deep convolutional neural network learned from different languages. In 2014 IEEE International Conference on Image Processing (ICIP), pages 2560-2564. IEEE, 2014. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 385, + 287, + 417 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 385, + 287, + 417 + ], + "spans": [ + { + "bbox": [ + 53, + 385, + 287, + 417 + ], + "type": "text", + "content": "[7] Eden Belouadah and Adrian Popescu. II2m: Class incremental learning with dual memory. In ICCV, pages 583-592, 2019. 1, 2, 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 419, + 287, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 419, + 287, + 453 + ], + "spans": [ + { + "bbox": [ + 53, + 419, + 287, + 453 + ], + "type": "text", + "content": "[8] Michal Bušta, Yash Patel, and Jiri Matas. E2e-plt-an unconstrained end-to-end method for multi-language scene text. In ACCV, pages 127–143. Springer, 2018. 1, 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 454, + 287, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 454, + 287, + 487 + ], + "spans": [ + { + "bbox": [ + 53, + 454, + 287, + 487 + ], + "type": "text", + "content": "[9] Francisco M Castro, Manuel J Marín-Jiménez, Nicolás Guil, Cordelia Schmid, and Karteek Alahari. End-to-end incremental learning. In ECCV, pages 233-248, 2018. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 488, + 287, + 520 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 488, + 287, + 520 + ], + "spans": [ + { + "bbox": [ + 48, + 488, + 287, + 520 + ], + "type": "text", + "content": "[10] Li Chen, Chunyan Yu, and Lvcai Chen. A new knowledge distillation for incremental object detection. In IJCNN, pages 1-7. IEEE, 2019. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 522, + 287, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 522, + 287, + 555 + ], + "spans": [ + { + "bbox": [ + 48, + 522, + 287, + 555 + ], + "type": "text", + "content": "[11] Shoufa Chen, Enze Xie, Chongjian GE, Runjian Chen, Ding Liang, and Ping Luo. CycleMLP: A MLP-like architecture for dense prediction. In ICLR, 2022. 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 557, + 287, + 590 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 557, + 287, + 590 + ], + "spans": [ + { + "bbox": [ + 48, + 557, + 287, + 590 + ], + "type": "text", + "content": "[12] Mark Collier, Efi Kokiopoulou, Andrea Gesmundo, and Jesse Berent. Routing networks with co-training for continual learning. ICML, 2020. 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 592, + 287, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 592, + 287, + 646 + ], + "spans": [ + { + "bbox": [ + 48, + 592, + 287, + 646 + ], + "type": "text", + "content": "[13] Jia Cui, Brian Kingsbury, Bhuvana Ramabhadran, George Saon, Tom Sercu, Kartik Audhkhasi, Abhinav Sethy, Markus Nussbaum-Thom, and Andrew Rosenberg. Knowledge distillation across ensembles of multilingual models for low-resource languages. In ICASSP, pages 4825-4829, 2017. 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 647, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 287, + 712 + ], + "type": "text", + "content": "[14] Matthias De Lange, Rahaf Aljundi, Marc Masana, Sarah Parisot, Xu Jia, Aleš Leonardis, Gregory Slabaugh, and Tinne Tuytelaars. A continual learning survey: Defying forgetting in classification tasks. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(7):3366-3385, 2022. 1, 2, 3" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "text", + "content": "[15] Prithviraj Dhar, Rajat Vikram Singh, Kuan-Chuan Peng, Ziyan Wu, and Rama Chellappa. Learning without memorizing. In CVPR, pages 5138-5146, 2019. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 108, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 108, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 108, + 545, + 150 + ], + "type": "text", + "content": "[16] Arthur Douillard, Yifu Chen, Arnaud Dapogny, and Matthieu Cord. Plop: Learning without forgetting for continual semantic segmentation. In CVPR, pages 4040-4050, 2021. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 154, + 545, + 196 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 154, + 545, + 196 + ], + "spans": [ + { + "bbox": [ + 307, + 154, + 545, + 196 + ], + "type": "text", + "content": "[17] Arthur Douillard, Alexandre Ramé, Guillaume Couairon, and Matthieu Cord. Dytox: Transformers for continual learning with dynamic token expansion. In CVPR, pages 9285–9295, 2022. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 200, + 545, + 243 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 200, + 545, + 243 + ], + "spans": [ + { + "bbox": [ + 307, + 200, + 545, + 243 + ], + "type": "text", + "content": "[18] Yongkun Du, Zhineng Chen, Caiyan Jia, Xiaoting Yin, Tianlun Zheng, Chenxia Li, Yuning Du, and Yu-Gang Jiang. SVTR: scene text recognition with a single visual model. In IJCAI, 2022. 3, 6" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 246, + 545, + 300 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 246, + 545, + 300 + ], + "spans": [ + { + "bbox": [ + 307, + 246, + 545, + 300 + ], + "type": "text", + "content": "[19] Shancheng Fang, Zhendong Mao, Hongtao Xie, Yuxin Wang, Chenggang Yan, and Yongdong Zhang. Abinet++: Autonomous, bidirectional and iterative language modeling for scene text spotting. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 1" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 303, + 545, + 346 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 303, + 545, + 346 + ], + "spans": [ + { + "bbox": [ + 307, + 303, + 545, + 346 + ], + "type": "text", + "content": "[20] Shancheng Fang, Hongtao Xie, Yuxin Wang, Zhendong Mao, and Yongdong Zhang. Read like humans: Autonomous, bidirectional and iterative language modeling for scene text recognition. In CVPR, pages 7094-7103, 2021. 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 349, + 545, + 390 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 349, + 545, + 390 + ], + "spans": [ + { + "bbox": [ + 307, + 349, + 545, + 390 + ], + "type": "text", + "content": "[21] Tao Feng, Mang Wang, and Hangjie Yuan. Overcoming catastrophic forgetting in incremental object detection via elastic response distillation. In CVPR, pages 9427-9436, 2022. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 394, + 545, + 437 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 394, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 307, + 394, + 545, + 437 + ], + "type": "text", + "content": "[22] Yasuhisa Fujii, Karel Driesen, Jonathan Baccash, Ash Hurst, and Ashok C Popat. Sequence-to-label script identification for multilingualOCR. In ICDAR, volume 1, pages 161-168. IEEE, 2017. 1, 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 440, + 545, + 462 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 440, + 545, + 462 + ], + "spans": [ + { + "bbox": [ + 307, + 440, + 545, + 462 + ], + "type": "text", + "content": "[23] Siavash Golkar, Michael Kagan, and Kyunghyun Cho. Continual learning via neural pruning. NIPS, 2019. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 464, + 545, + 507 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 464, + 545, + 507 + ], + "spans": [ + { + "bbox": [ + 307, + 464, + 545, + 507 + ], + "type": "text", + "content": "[24] Lluis Gomez, Anguelos Nicolaou, and Dimosthenis Karatzas. Improving patch-based scene text script identification with ensembles of conjoined networks. Pattern Recognition, 67:85-96, 2017. 1, 3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 510, + 545, + 563 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 510, + 545, + 563 + ], + "spans": [ + { + "bbox": [ + 307, + 510, + 545, + 563 + ], + "type": "text", + "content": "[25] Qibin Hou, Zihang Jiang, Li Yuan, Ming-Ming Cheng, Shuicheng Yan, and Jiashi Feng. Vision permutator: A permutable mlp-like architecture for visual recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 7" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 567, + 545, + 609 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 567, + 545, + 609 + ], + "spans": [ + { + "bbox": [ + 307, + 567, + 545, + 609 + ], + "type": "text", + "content": "[26] Wenyang Hu, Xiaocong Cai, Jun Hou, Shuai Yi, and Zhiping Lin. Gtc: Guided training of ctc towards efficient and accurate scene text recognition. In AAAI, volume 34, pages 11005-11012, 2020. 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 613, + 545, + 666 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 613, + 545, + 666 + ], + "spans": [ + { + "bbox": [ + 307, + 613, + 545, + 666 + ], + "type": "text", + "content": "[27] Xinting Hu, Kaihua Tang, Chunyan Miao, Xian-Sheng Hua, and Hanwang Zhang. Distilling causal effect of data in class incremental learning. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3957-3966, 2021. 1" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 670, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 670, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 670, + 545, + 713 + ], + "type": "text", + "content": "[28] Bingchen Huang, Zhineng Chen, Peng Zhou, Jiayin Chen, and Zuxuan Wu. Resolving task confusion in dynamic expansion architectures for class incremental learning. In AAAI, volume 37, pages 908-916, 2023. 1, 2" + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "18652" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 714 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[29] Jing Huang, Guan Pang, Rama Kovvuri, Mandy Toh, Kevin J Liang, Praveen Krishnan, Xi Yin, and Tal Hassner. A multiplexed network for end-to-end, multilingualOCR. In CVPR, pages 4547-4557, 2021. 1, 3, 5" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 118, + 287, + 183 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 118, + 287, + 183 + ], + "spans": [ + { + "bbox": [ + 48, + 118, + 287, + 183 + ], + "type": "text", + "content": "[30] James Kirkpatrick, Razvan Pascanu, Neil Rabinowitz, Joel Veness, Guillaume Desjardins, Andrei A Rusu, Kieran Milan, John Quan, Tiago Ramalho, Agnieszka Grabska-Barwinska, et al. Overcoming catastrophic forgetting in neural networks. Proceedings of the national academy of sciences, 114(13):3521-3526, 2017. 2, 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 185, + 287, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 185, + 287, + 217 + ], + "spans": [ + { + "bbox": [ + 48, + 185, + 287, + 217 + ], + "type": "text", + "content": "[31] Zhizhong Li and Derek Hoiem. Learning without forgetting. IEEE transactions on pattern analysis and machine intelligence, 40(12):2935-2947, 2017. 6, 7" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 219, + 287, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 219, + 287, + 262 + ], + "spans": [ + { + "bbox": [ + 48, + 219, + 287, + 262 + ], + "type": "text", + "content": "[32] An-An Liu, Haochun Lu, Heyu Zhou, Tianbao Li, and Mohan Kankanhalli. Balanced class-incremental 3d object classification and retrieval. IEEE Transactions on Knowledge and Data Engineering, 2023. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 264, + 286, + 286 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 264, + 286, + 286 + ], + "spans": [ + { + "bbox": [ + 48, + 264, + 286, + 286 + ], + "type": "text", + "content": "[33] Hanxiao Liu, Zihang Dai, David So, and Quoc V Le. Pay attention to mlps. NIPS, 34:9204-9215, 2021. 7" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 287, + 287, + 352 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 287, + 287, + 352 + ], + "spans": [ + { + "bbox": [ + 48, + 287, + 287, + 352 + ], + "type": "text", + "content": "[34] Nibal Nayef, Yash Patel, Michal Busta, Pinaki Nath Chowdhury, Dimosthenis Karatzas, Wafa Khlif, Jiri Matas, Umapada Pal, Jean-Christophe Burie, Cheng-lin Liu, et al. Icdar2019 robust reading challenge on multi-lingual scene text detection and recognition—rrc-plt-2019. In ICDAR, pages 1582–1587. IEEE, 2019. 1, 3, 5" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 354, + 287, + 419 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 354, + 287, + 419 + ], + "spans": [ + { + "bbox": [ + 48, + 354, + 287, + 419 + ], + "type": "text", + "content": "[35] Nibal Nayef, Fei Yin, Imen Bizid, Hyunsoo Choi, Yuan Feng, Dimosthenis Karatzas, Zhenbo Luo, Umapada Pal, Christophe Rigaud, Joseph Chazalon, et al. Icdar2017 robust reading challenge on multi-lingual scene text detection and script identification-rrc-plt. In ICDAR, volume 1, pages 1454-1459. IEEE, 2017. 3, 5" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 421, + 287, + 464 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 421, + 287, + 464 + ], + "spans": [ + { + "bbox": [ + 48, + 421, + 287, + 464 + ], + "type": "text", + "content": "[36] German I Parisi, Ronald Kemker, Jose L Part, Christopher Kanan, and Stefan Wermter. Continual lifelong learning with neural networks: A review. Neural Networks, 113:54-71, 2019. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 466, + 287, + 509 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 466, + 287, + 509 + ], + "spans": [ + { + "bbox": [ + 48, + 466, + 287, + 509 + ], + "type": "text", + "content": "[37] Sylvestre-Alvise Rebuffi, Alexander Kolesnikov, Georg Sperl, and Christoph H Lampert. icarl: Incremental classifier and representation learning. In CVPR, pages 2001–2010, 2017. 1, 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 510, + 287, + 544 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 510, + 287, + 544 + ], + "spans": [ + { + "bbox": [ + 48, + 510, + 287, + 544 + ], + "type": "text", + "content": "[38] Fenfen Sheng, Zhineng Chen, and Bo Xu. Ntrr: A no-recurrence sequence-to-sequence model for scene text recognition. In ICDAR, pages 781-786, 2019. 1, 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 545, + 287, + 599 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 545, + 287, + 599 + ], + "spans": [ + { + "bbox": [ + 48, + 545, + 287, + 599 + ], + "type": "text", + "content": "[39] Baoguang Shi, Xiang Bai, and Cong Yao. An end-to-end trainable neural network for image-based sequence recognition and its application to scene text recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 39(11):2298-2304, 2017. 1, 3, 6" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 601, + 287, + 655 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 601, + 287, + 655 + ], + "spans": [ + { + "bbox": [ + 48, + 601, + 287, + 655 + ], + "type": "text", + "content": "[40] Baoguang Shi, Mingkun Yang, Xinggang Wang, Pengyuan Lyu, Cong Yao, and Xiang Bai. Aster: An attentional scene text recognizer with flexible rectification. IEEE Transactions on Pattern Analysis and Machine Intelligence, 41(9):2035-2048, 2018. 1, 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 657, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 657, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 657, + 287, + 689 + ], + "type": "text", + "content": "[41] Baoguang Shi, Cong Yao, Chengquan Zhang, Xiaowei Guo, Feiyue Huang, and Xiang Bai. Automatic script identification in the wild. In ICDAR, pages 531-535. IEEE, 2015. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "type": "text", + "content": "[42] Leslie N Smith and Nicholay Topin. Super-convergence: Very fast training of neural networks using large learning" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 632 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 106 + ], + "type": "text", + "content": "rates. In Artificial intelligence and machine learning for multi-domain operations applications, volume 11006, pages 369-386. SPIE, 2019. 6" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 107, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 107, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 308, + 107, + 545, + 150 + ], + "type": "text", + "content": "[43] Yuxin Wang, Hongtao Xie, Shancheng Fang, Jing Wang, Shenggao Zhu, and Yongdong Zhang. From two to one: A new scene text recognizer with visual language modeling network. In ICCV, pages 14174-14183, 2021. 1, 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 152, + 545, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 152, + 545, + 206 + ], + "spans": [ + { + "bbox": [ + 308, + 152, + 545, + 206 + ], + "type": "text", + "content": "[44] Yuxin Wang, Hongtao Xie, Shancheng Fang, Mengting Xing, Jing Wang, Shenggao Zhu, and Yongdong Zhang. Petr: Rethinking the capability of transformer-based language model in scene text recognition. IEEE Transactions on Image Processing, 31:5585-5598, 2022. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 207, + 545, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 207, + 545, + 239 + ], + "spans": [ + { + "bbox": [ + 308, + 207, + 545, + 239 + ], + "type": "text", + "content": "[45] Yeming Wen, Dustin Tran, and Jimmy Ba. Batchsemble: an alternative approach to efficient ensemble and lifelong learning. In ICLR, 2020. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 241, + 545, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 241, + 545, + 274 + ], + "spans": [ + { + "bbox": [ + 308, + 241, + 545, + 274 + ], + "type": "text", + "content": "[46] Shipeng Yan, Jiangwei Xie, and Xuming He. Der: Dynamically expandable representation for class incremental learning. In CVPR, pages 3014-3023, 2021. 1, 2, 3, 6, 7, 8" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 276, + 545, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 276, + 545, + 330 + ], + "spans": [ + { + "bbox": [ + 308, + 276, + 545, + 330 + ], + "type": "text", + "content": "[47] Dongbao Yang, Yu Zhou, Xiaopeng Hong, Aoting Zhang, and Weiping Wang. One-shot replay: Boosting incremental object detection via retrospecting one object. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 37, pages 3127-3135, 2023. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 331, + 545, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 331, + 545, + 374 + ], + "spans": [ + { + "bbox": [ + 308, + 331, + 545, + 374 + ], + "type": "text", + "content": "[48] Dongbao Yang, Yu Zhou, Aoting Zhang, Xurui Sun, Dayan Wu, Weiping Wang, and Qixiang Ye. Multi-view correlation distillation for incremental object detection. Pattern Recognition, 131:108863, 2022. 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 376, + 545, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 376, + 545, + 430 + ], + "spans": [ + { + "bbox": [ + 308, + 376, + 545, + 430 + ], + "type": "text", + "content": "[49] Guanglei Yang, Enrico Fini, Dan Xu, Paolo Rota, Mingli Ding, Moin Nabi, Xavier Alameda-Pineda, and Elisa Ricci. Uncertainty-aware contrastive distillation for incremental semantic segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 432, + 545, + 464 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 432, + 545, + 464 + ], + "spans": [ + { + "bbox": [ + 308, + 432, + 545, + 464 + ], + "type": "text", + "content": "[50] Friedemann Zenke, Ben Poole, and Surya Ganguli. Continual learning through synaptic intelligence. In ICML, pages 3987-3995. PMLR, 2017. 2" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 465, + 545, + 509 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 465, + 545, + 509 + ], + "spans": [ + { + "bbox": [ + 308, + 465, + 545, + 509 + ], + "type": "text", + "content": "[51] Chang-Bin Zhang, Jia-Wen Xiao, Xialei Liu, Ying-Cong Chen, and Ming-Ming Cheng. Representation compensation networks for continual semantic segmentation. In CVPR, pages 7053-7064, 2022. 1, 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 510, + 545, + 553 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 510, + 545, + 553 + ], + "spans": [ + { + "bbox": [ + 308, + 510, + 545, + 553 + ], + "type": "text", + "content": "[52] Bowen Zhao, Xi Xiao, Guojun Gan, Bin Zhang, and Shu-Tao Xia. Maintaining discrimination and fairness in class incremental learning. In CVPR, pages 13208-13217, 2020. 1, 6" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 555, + 545, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 555, + 545, + 588 + ], + "spans": [ + { + "bbox": [ + 308, + 555, + 545, + 588 + ], + "type": "text", + "content": "[53] Tianlun Zheng, Zhineng Chen, Jinfeng Bai, Hongtao Xie, and Yu-Gang Jiang. Tps++: Attention-enhanced thin-plate spline for scene text recognition. *IJCAI*, 2023. 1" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 589, + 545, + 632 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 589, + 545, + 632 + ], + "spans": [ + { + "bbox": [ + 308, + 589, + 545, + 632 + ], + "type": "text", + "content": "[54] Tianlun Zheng, Zhineng Chen, Shancheng Fang, Hongtao Xie, and Yu-Gang Jiang. Cdistnet: Perceiving multi-domain character distance for robust text recognition. arXiv preprint arXiv:2111.11011, 2021. 3" + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "18653" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/18b3712a-f7d6-4a6b-8811-754fd084ad1d_content_list.json b/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/18b3712a-f7d6-4a6b-8811-754fd084ad1d_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..1499e73b67bca9c20244bdcb6dbf36658375d960 --- /dev/null +++ b/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/18b3712a-f7d6-4a6b-8811-754fd084ad1d_content_list.json @@ -0,0 +1,1586 @@ +[ + { + "type": "text", + "text": "MSI: Maximize Support-Set Information for Few-Shot Segmentation", + "text_level": 1, + "bbox": [ + 137, + 130, + 833, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Seonghyeon Moon\nRutgers University", + "bbox": [ + 148, + 181, + 303, + 215 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "sm2062@rutgers.edu", + "bbox": [ + 145, + 219, + 308, + 232 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Samuel S. Sohn \nRutgers University", + "bbox": [ + 383, + 181, + 532, + 217 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "samuel.sohn@rutgers.edu", + "bbox": [ + 354, + 220, + 558, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Honglu Zhou \nNEC Laboratories America", + "bbox": [ + 602, + 181, + 823, + 215 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "hozhou@nec-labs.com", + "bbox": [ + 627, + 220, + 799, + 232 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Sejong Yoon", + "bbox": [ + 308, + 242, + 415, + 258 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The College of New Jersey", + "bbox": [ + 254, + 260, + 470, + 277 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "yoons@tcnj.edu", + "bbox": [ + 297, + 280, + 426, + 292 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Vladimir Pavlovic \nRutgers University", + "bbox": [ + 549, + 242, + 699, + 277 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "vladimir@rutgers.edu", + "bbox": [ + 534, + 279, + 712, + 292 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Muhammad Haris Khan \nMohamed Bin Zayed University of Artificial Intelligence", + "bbox": [ + 112, + 301, + 565, + 337 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "muhammad.haris@mbzuai.ac.ae", + "bbox": [ + 217, + 340, + 460, + 353 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Mubbasir Kapadia \nRutgers University", + "bbox": [ + 653, + 301, + 805, + 337 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "mubbasir.kapadia@rutgers.edu", + "bbox": [ + 604, + 340, + 854, + 354 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 388, + 312, + 405 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "FSS (Few-shot segmentation) aims to segment a target class using a small number of labeled images (support set). To extract information relevant to the target class, a dominant approach in best performing FSS methods removes background features using a support mask. We observe that this feature excision through a limiting support mask introduces an information bottleneck in several challenging FSS cases, e.g., for small targets and/or inaccurate target boundaries. To this end, we present a novel method (MSI), which maximizes the support-set information by exploiting two complementary sources of features to generate super correlation maps. We validate the effectiveness of our approach by instantiating it into three recent and strong FSS methods. Experimental results on several publicly available FSS benchmarks show that our proposed method consistently improves performance by visible margins and leads to faster convergence. Our code and trained models are available at: https://github.com/moonsh/MSI-Maximize-Support-Set-Information", + "bbox": [ + 76, + 421, + 473, + 708 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 738, + 209, + 753 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Deep convolutional neural networks (DCNNs) have achieved state-of-the-art results across several mainstream computer vision (CV) problems, including object detection [26, 27] and semantic segmentation [18, 2, 38]. An important factor underlying the success of DCNNs is large-scale annotated datasets, which are costly and cumbersome to acquire in many dense prediction tasks, such as semantic segmentation. Moreover, these models struggle to segment novel objects when only a few annotated examples are", + "bbox": [ + 75, + 763, + 468, + 902 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "(a)", + "bbox": [ + 519, + 417, + 534, + 429 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/c29d178004acd6070f5e01dc9699b87f415ed6e6d2f369282e92888ffcdc82a9.jpg", + "image_caption": [ + "Figure 1. Recent FSS baseline (VAT[9]) struggles to accurately segment the target object in several challenging scenarios in PASCAL [5] and $\\mathrm{COCO}^i$ [15]: (a) the same instance of the target class is not masked, e.g., the sofa on the right, (b) the support mask is very small compared to the entire image, e.g., flowers in the pot, (c) support mask is missing some target boundary information, e.g., the front and chimney of the train, and (d) the background contains some important contextual information, unavailable in the support mask, e.g., shoes and grass. Our method (MSI) is capable of accurately segmenting target objects. It maximizes the support set information to compensate for the limited support mask information and can exploit relevant contextual information from the background." + ], + "image_footnote": [], + "bbox": [ + 544, + 388, + 870, + 625 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "available. Many existing few-shot segmentation (FSS) approaches [25, 30, 34, 23, 31, 33, 35, 13, 32, 16, 37, 19, 21, 11, 12, 9, 22] aim to address this shortcoming. The problem settings in FSS require accurate segmentation of a target ob", + "bbox": [ + 498, + 839, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "19266", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/f0d470f213d76468e071e8e9bc82cb6c1945c1b775be733ee3345b61edffdbbf.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 101, + 89, + 421, + 186 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/6fd00709779a12f4c7e062650f4900735b403bd52b695f959c2ea943a88b5072.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 99, + 191, + 449, + 286 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/ea065c0dcf99bb48f1ac21ed1012e5f370231929e8b3bc75fc28334d78109dc4.jpg", + "image_caption": [ + "Figure 2. (a) Many FSS methods use support mask to remove background features [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12], denoted as feature masking (FM), and so rely only on target object features. (b) Recent work, HM [22], merges both image masking and feature masking to achieve hybrid masking for improving target information. (c) We propose to maximize the support set information (MSI) to compensate for the limited support mask information and exploit relevant contextual information from the background." + ], + "image_footnote": [], + "bbox": [ + 99, + 292, + 449, + 386 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "ject in a query image, given few annotated images, termed the support set, from the target class.", + "bbox": [ + 75, + 532, + 467, + 561 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Shaban et al.'s work [28] introduced the first FSS model, in which a masked support image was used to extract only the target features. Using the target features, both segmentation and conditioning branches are trained to segment an object of the target class. Later, Zhang et al. [37] show that extracting target features using masked average pooling (MAP) is more beneficial for network learning than obtaining features by masking images. Since then, many FSS models [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12] have considered MAP as the de facto technique for obtaining target features and focus on improving the encoder/decoder network. Recently, HSNet [21] proposed to utilize more effective target features extracted from multiple layers of a deep backbone network. Likewise, ASNet [11] and VAT [9] proposed different network architectures to harness deep features.", + "bbox": [ + 75, + 565, + 467, + 805 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Despite promising results, many recent methods, including HSNet [21], ASNet [11], and VAT [9], systematically struggle with few challenging FSS cases (Fig. 1): (a) When the support mask does not mask all instances of the same target class; (b) The support mask is unable to faithfully capture object boundaries; (c) The support mask is too", + "bbox": [ + 75, + 810, + 467, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "small, carrying limited object information; and (d) The background contains some important contextual information, unavailable in the support mask, for accurately segmenting the target object. We conjecture that this happens because many current SOTA methods rely on support masks to completely remove the background (Fig. 2), which limits the useful information in several challenging FSS cases.", + "bbox": [ + 496, + 90, + 890, + 196 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this paper, we propose a new method to overcome the limited information bottleneck from the support mask. It is based on the intuition that upon maximizing the information from the masked support set images (MSI), it is possible to compensate for the limited support mask information by utilizing the important contextual information available in the typically discarded background (Fig. 2). MSI jointly exploits two complementary sources of features. The first set of features is obtained by using masked support images, which only activate the target-related features in the query image. The second set of features is generated from the full support images, which activate the features of all similar objects shared between the support and query images. The former features act as an anchor for the latter in localizing a certain target class while supplementing it with the target boundary information. We summarize our key contributions as follows:", + "bbox": [ + 496, + 198, + 890, + 450 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose MSI, an efficient and effective plug-and-play module for FSS methods. MSI harnesses masked support images to capture the delineated target information and exploits the entire support image for complete target information.", + "- We perform extensive experiments and analysis on three challenging FSS benchmarks: PASCAL- $5^{i}$ [5], COCO- $20^{i}$ [15], and FSS-1000 [14]. Results show that MSI consistently improves mIoU in the one-shot setting over all strong baselines, including HSNet [21], ASNet [11], and VAT [9].", + "- MSI improves the training speed of recent baseline models on PASCAL-5 $^i$ [5], with 3.3x average speed-up on VAT [8] and 4.5x on HSNet [21]." + ], + "bbox": [ + 517, + 453, + 890, + 664 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Works", + "text_level": 1, + "bbox": [ + 500, + 679, + 648, + 694 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Few-shot segmentation: OSLSM [28] is considered to be the first work introducing FSS problem. OSLSM proposed a model consisting of a condition branch and a segmentation branch. Since OSLSM, various methods have been proposed to solve the FSS problem [25, 30, 34, 23, 31, 33, 35, 13, 32, 16, 37, 19, 21, 11, 12, 9, 22].", + "bbox": [ + 496, + 704, + 890, + 794 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "MAP (Masked Average Pooling): Zhang et al. [37] proposed the MAP to collect target information from the support set. MAP masks features instead of masking support images and uses average pooling to extract target information. They argued that (1) removing the background from support images increases the variance of the input data for a unified network and (2) masking the im", + "bbox": [ + 496, + 795, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "19267", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "age will make the network biased toward the target image. For these reasons, MAP was recommended to get target features. Since Zhang et al. [37], many few shot works [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12] are following MAP to extract target features. However, by performing average pooling, spatial information is inevitably lost [10]. In this work, we utilized the masked support image to generate target features without using MAP. Therefore, we can retrieve fine-detail texture information and preserve spatial information.", + "bbox": [ + 75, + 90, + 472, + 241 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Multi-layer features: Instead of using MAP, HSNet [21] proposed to use deep features extracted from multiple layers and designed an effective convolution to process the features. To process the deep features effectively and efficiently, VAT [8] proposed a model based on the swim transformer [17] and ASNet [11] proposed the attentive squeeze network. HM [22] proposed hybrid masking to compensate for the lost details in feature masking. Although the spatial information that MAP lost was preserved, these works extracted target features counting on support masks. Therefore, when the support masks give limited information, limited target information is extracted. In this paper, not only is information loss minimized when the target features are extracted by relying on the support mask, but also more meaningful target features are extracted by utilizing both the entire support image and the masked support image.", + "bbox": [ + 75, + 244, + 472, + 487 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Utilizing background information: There have been several attempts to improve FSS accuracy by using background information [34, 12]. PMM [34] proposed a method of deactivating the background and activating the target object using a duplex manner. Negative learning was carried out with objects in the background, and on the other hand, positive learning was conducted using the foreground object. Afterward, the two learning results were used to segment the target object accurately. Similarly, BAM [12] also proposed to use two learners. The base learner was trained using objects in the background and a meta learner was trained with the foreground object. These two learners were integrated to predict segmentation accurately. However, they assumed that the background lacks meaningful target information. Therefore, they missed target information that might exist in the background. We obtain even more target information from the background and simultaneously utilize background information to avoid segmenting wrong objects.", + "bbox": [ + 75, + 489, + 472, + 777 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Cross attention: Both CyCTR [36] and DCAMA [29] utilize the transformer architecture to achieve cross-attention between the support and query features. This cross-attention allows the identification of target information beyond the mask area. Despite this, both methods rely on an unmasked support image to extract target information, leading to the loss of delineated detailed target information. On the contrary, MSI proposes to directly provide the model", + "bbox": [ + 75, + 779, + 472, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "with features from the masked support image and the full support image, thereby introducing a strong inductive bias that ultimately leads to better performance. MSI computes the cosine similarity between these two complementary sets of features and concatenates them. Therefore, MSI can retain detailed target information. It is more intuitive and simpler and can be plugged seamlessly into various FSS baselines, as validated in our experiments.", + "bbox": [ + 496, + 90, + 893, + 212 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Overall Method", + "text_level": 1, + "bbox": [ + 500, + 223, + 658, + 239 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Fig. 3 displays the overall architecture of our method. Following recent works [21, 11, 9], it consists of a backbone network (ResNet-50 [7] or ResNet-101 [7]) pre-trained on ImageNet [4] to obtain multi-layer features, and an encoder/decoder network to predict the segmentation mask. We propose a new plug-and-play module to maximize the support set information (MSI), which compensates for limited support mask information by exploiting relevant contextual information from the background. MSI extracts support target features (STF), containing delineated target class information from the support images, and support image features (SIF), accounting for the information in the entire support image. Next, STF and SIF are leveraged to obtain their respective correlation maps by computing the cosine similarity with respect to the query features (QF) obtained from the query image. Then, the correlation maps corresponding to STF and SIF are utilized to get super correlation maps (SCM). Finally, this SCM is used as the input to the encoder and decoder which can be from recent FSS methods (e.g., [21], [9], and [11]).", + "bbox": [ + 496, + 248, + 893, + 551 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Preliminaries", + "text_level": 1, + "bbox": [ + 500, + 559, + 640, + 574 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The goal of few-shot segmentation is to train a model that can segment the target object in a query image when provided with a few annotated example images from the target class. Following prior work in FSS [21, 11, 9], we utilize the episodic scheme for training our model.", + "bbox": [ + 496, + 582, + 893, + 657 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Specifically, we assume the availability of two disjoint sets, $C_{train}$ and $C_{test}$ as training and testing classes, respectively. The training data $D_{train}$ is sampled from $C_{train}$ and the testing data $D_{test}$ is from $C_{test}$ . We then construct multiple episodes from $D_{train}$ and $D_{test}$ . An episode is comprised of a support set, $S = (I^s, M^s)$ , and a query set, $Q = (I^q, M^q)$ , where $I^*$ and $M^*$ denote an image and its corresponding mask. Furthermore, $D_{train} = \\{(S_i, Q_i)\\}_{i=1}^{N_{train}}$ and $D_{test} = \\{(S_i, Q_i)\\}_{i=1}^{N_{test}}$ , where $N_{train}$ represents the number of episodes for training and $N_{test}$ is the number of episodes for testing. During training, we iteratively sample episodes from $D_{train}$ to train a model that learns a mapping from $(I^s, M^s, I^q)$ to query mask $M^q$ . The learned model is used without further optimization by randomly sampling episodes from the testing data $D_{test}$ in the same manner and comparing the predicted query masks to the ground truth.", + "bbox": [ + 496, + 657, + 893, + 902 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "19268", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/517280b1a0d18b5736c3ca7e96103b434df1c87440015071ad4acef8ff5e6350.jpg", + "image_caption": [ + "Figure 3. Overall architecture. To maximize the usability of the support set, first we extract support image features (SIF) and support target features (STF) through the backbone. SIF branch creates features using the entire support image, and STF branch extracts the features after removing background pixels. The query features (QF) are obtained from the query. We obtain correlation maps by calculating the cosine similarity (CS) of the STF and SIF with the QF, respectively, and these correlation maps are concatenated to make super correlation maps (SCM). $CS_2$ represents the cosine similarity between the target object and the query image. Therefore, only target-related information in the query image will be activated. $CS_1$ , on the other hand, assesses the cosine similarity between the entire support image and the query image. Consequently, all the similar objects between the support image and the query image are activated." + ], + "image_footnote": [], + "bbox": [ + 147, + 88, + 637, + 275 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/778e68e85738e753d0cbc0cd70b6ccfae1ae97589b11cf873941735e943c6888.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 650, + 89, + 823, + 273 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Maximizing Support-Set Information: MSI", + "text_level": 1, + "bbox": [ + 76, + 401, + 444, + 416 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "An important question for the FSS pipeline is where in a network it is most suitable to use masking to provide target information to the network. Earlier attempts, such as the work of Shaban et al. [28] suggested masking the background in the input image so that only target features are obtained. The rationale was that the network would supposedly be biased toward large objects, so removing the background would decrease the variance of the output parameters. Later, Zhang et al. [37] proposed to mask the background after extracting features because masking the input image makes a network biased towards the target image and changes the statistical distribution of the support image set. Many recent state-of-the-art methods have conformed to this approach [34, 33, 31, 23, 35, 16, 13, 36, 21, 9, 11, 12].", + "bbox": [ + 75, + 426, + 467, + 638 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Motivation: Although these methods report promising performance, we note that many recent methods, including HSNet [21], ASNet [11], and VAT [9], struggle to accurately predict the segmentation mask in several challenging scenarios (Fig. 1). We believe that this occurs because many recent FSS methods fully rely on the support mask to remove the background features (Fig. 2). These support masks likely present an information bottleneck in such challenging cases. For instance, when they are very small, they fail to properly encapsulate target object boundaries or do not capture all instances of the target object.", + "bbox": [ + 75, + 641, + 467, + 806 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We put forth a new approach (MSI) to alleviate the aforementioned limitations of support masks. We believe that by maximizing the information from support images, it becomes possible to compensate for the limited information in the support mask and also leverage important contextual information available in the background. Specifically, we", + "bbox": [ + 75, + 810, + 467, + 900 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "extract support target features (STF), which contain delineated target class information in the support image, and support image features (SIF), which contain contextualized information from the entire support image. This is because the STF enables the acquisition of more focused and fine-grained target information, and compared to feature masking (Fig. 2) STF captures more accurate object boundaries because the receptive field can cover even the area beyond target object at deep features [20, 22]. On the other hand, SIF utilizes the full support image to capture relevant and useful target information that exists in the background. This allows us to obtain both detailed and complete information about the target class to avoid segmenting wrong objects. We leverage STF and SIF to obtain their respective correlation maps by computing their cosine similarity with the query features (QF), which are obtained from the query image. The correlation maps corresponding to STF and SIF are then combined into Super Correlation Maps (SCM), which are inputted to the encoder and decoder.", + "bbox": [ + 496, + 401, + 890, + 686 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Formalizing STF and SIF: Support image features (SIF), $\\alpha_{i=1}^{N}$ , where $N$ is the number of features, refer to the features of the entire support image, $I^{S} \\in \\mathbb{R}^{3 \\times w \\times h}$ , where $w$ is the width and $h$ is the height of the image. Support target features (STF), $\\beta_{i=1}^{N}$ , are the features from the target image, $I^{T} \\in \\mathbb{R}^{3 \\times w \\times h}$ , which is a masked support image using support mask $\\mathbf{M}^{S} \\in \\{0,1\\}^{w \\times h}$ . Formally,", + "bbox": [ + 496, + 689, + 890, + 795 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nI ^ {T} = I ^ {S} \\odot \\zeta (M ^ {S}), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 627, + 806, + 890, + 825 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\zeta (\\cdot)$ resizes the mask $M^S$ to fit the dimension of the image $I^{S}$ and $\\odot$ denotes the Hadamard product. Query features (QF), $\\kappa_{i = 1}^{N}$ , are obtained from the query image, $I^Q\\in \\mathbb{R}^{3\\times w\\times h}$", + "bbox": [ + 496, + 839, + 890, + 898 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "19269", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "For each image $(I^S, I^T, \\text{and} I^Q)$ , the backbone network, $\\triangleleft$ , produces $N$ number of features $(\\alpha_{i=1}^N, \\beta_{i=1}^N, \\text{and} \\kappa_{i=1}^N$ respectively) from its intermediate layers.", + "bbox": [ + 76, + 90, + 468, + 137 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\alpha_ {i = 1} ^ {N} = \\triangleleft (I ^ {S}), \\beta_ {i = 1} ^ {N} = \\triangleleft (I ^ {T}), \\kappa_ {i = 1} ^ {N} = \\triangleleft (I ^ {Q}), (2)\n$$\n", + "text_format": "latex", + "bbox": [ + 99, + 145, + 468, + 167 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where features, $\\alpha_{i},\\beta_{i},\\kappa_{i}\\in \\mathbb{R}^{c_{i}\\times w_{i}\\times h_{i}}$ , have different sizes of channel and spatial dimensions. Features extracted from deeper layers have a large number of channels with smaller width and height dimensions.", + "bbox": [ + 76, + 176, + 468, + 236 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Super Correlation Maps (SCM): We calculate the cosine similarities of $\\alpha_{i=1}^{N}$ and $\\beta_{i=1}^{N}$ with respect to $\\kappa_{i=1}^{N}$ using the Eq. 3 to get correlation maps $C_i \\in \\mathbb{R}^{1 \\times w_i \\times h_i \\times w_i \\times h_i}$ and $S_i \\in \\mathbb{R}^{1 \\times w_i \\times h_i \\times w_i \\times h_i}$ . To perform multiplication between features, we reshape and transpose the features, $\\alpha_{i=1}^{N}, \\beta_{i=1}^{N}$ , and $\\kappa_{i=1}^{N}$ into $\\alpha_{i=1}^{\\prime N} \\in \\mathbb{R}^{(w_i \\cdot h_i) \\times c_i}$ , $\\beta_{i=1}^{\\prime N} \\in \\mathbb{R}^{(w_i \\cdot h_i) \\times c_i}$ , and $\\kappa_{i=1}^{\\prime N} \\in \\mathbb{R}^{c_i \\times (w_i \\cdot h_i)}$ .", + "bbox": [ + 76, + 237, + 468, + 348 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nC S _ {1} = C _ {i = 1} ^ {N} = \\operatorname {R e L U} \\left(\\frac {\\alpha_ {i = 1} ^ {\\prime N} \\cdot \\kappa_ {i = 1} ^ {\\prime N}}{\\| \\alpha_ {i = 1} ^ {\\prime N} \\| \\| \\kappa_ {i = 1} ^ {\\prime N} \\|}\\right), \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 125, + 357, + 468, + 401 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nC S _ {2} = S _ {i = 1} ^ {N} = \\mathrm {R e L U} \\bigg (\\frac {\\beta_ {i = 1} ^ {\\prime N} \\cdot \\kappa_ {i = 1} ^ {\\prime N}}{\\| \\beta_ {i = 1} ^ {\\prime N} \\| \\| \\kappa_ {i = 1} ^ {\\prime N} \\|} \\bigg),\n$$\n", + "text_format": "latex", + "bbox": [ + 127, + 397, + 418, + 435 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $N$ the is number of features and ReLU [6] removes inactivated and noisy values in the correlation map $C_i$ and $S_{i}$ . Correlation maps $C_{i = 1}^{N}$ and $S_{i = 1}^{N}$ are concatenated along the first dimension to obtain the Super Correlation Maps (SCM), $P_{i = 1}^{N}\\in \\mathbb{R}^{2\\times w_{i}\\times h_{i}\\times w_{i}\\times h_{i}}$ (Eq. 4).", + "bbox": [ + 76, + 443, + 468, + 521 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nS C M = P _ {i = 1} ^ {N} = \\left[ C _ {i = 1} ^ {N} \\oplus S _ {i = 1} ^ {N} \\right], \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 161, + 527, + 468, + 549 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\oplus$ denotes the concatenation.", + "bbox": [ + 76, + 558, + 315, + 571 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.3. Encoder and Decoder Architecture", + "text_level": 1, + "bbox": [ + 76, + 582, + 382, + 597 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "SCM can be fed as input to any encoder and decoder architecture of FSS methods. In order to validate our proposed method, we experiment with feeding SCM as input to three recent and strong encoder-decoder based FSS methods: HSNet [21], ASNet [11], and VAT [8]. For HSNet and VAT, the input channel size of the encoder in the models was doubled. For ASNet, SCM is merged using depth-wise attention based on Attention U-Net [24] instead of changing the input channel size. Otherwise, the architectures of the models were unchanged.", + "bbox": [ + 76, + 604, + 468, + 756 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 768, + 209, + 786 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Datasets: We use three widely used and publicly available datasets for evaluating our method (MSI): PASCAL- $5^{i}$ [5], COCO- $20^{i}$ [15] and FSS-1000 [14]. PASCAL- $5^{i}$ consists of 20 classes, whereas COCO- $20^{i}$ has 100 classes and FSS-1000 contains 1000 classes. Following previous works [21, 11, 9], we cross validate using 4 folds for PASCAL- $5^{i}$ and COCO- $20^{i}$ and we divide the classes into 4", + "bbox": [ + 76, + 794, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "groups for training and testing. Therefore, 5 and 20 classes are used for each fold testing on PASCAL- $5^{i}$ and COCO $20^{i}$ , respectively. Other remaining classes are used for training. For FSS-1000, 1000 classes are divided into 520, 240 and 240 for the training, validation and testing. Lastly, in order to evaluate the generalizability of our method, COCO $20^{i}$ is used for training, and PASCAL- $5^{i}$ for testing. To avoid class overlapping between training and testing, following previous works [21, 31], we change the PASCAL- $5^{i}$ class order for each fold.", + "bbox": [ + 496, + 90, + 890, + 241 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Implementation details: We incorporate MSI into three baseline models, HSNet [21], VAT [8], and ASNet [11], and refer to them as HSNet + MSI, ASNet + MS and VAT + MSI. The backbone networks, ResNet50 [7] and ResNet101 [7], are pre-trained on ImageNet [4], and are used to extract deep features following HSNet, ASNet, and VAT (features from conv3_x to conv5_x before the ReLU [6] activation of each layer stacked to form the deep features). No fine-tuning of backbones was performed. For a fair comparison with the existing models, we keep their default hyperparameters, as listed in their codebases. For VAT training, CATs data augmentation [3] was used and the batch size was reduced due to GPU memory limitations. Specifically, the batch sizes 4, 8, and 4 were used for PASCAL $^{5^i}$ [5], COCO-20 $^{i}$ [15], and FSS-1000 [14] respectively. No data augmentation was employed for training HSNet + MSI and ASNet + MSI.", + "bbox": [ + 496, + 242, + 892, + 498 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Super-correlation maps for K-Shots>1: Given a query image and K support-set images, we compute SCM for each query-support pair, resulting in K SCMs and K corresponding mask predictions from the model. All predictions are summed and normalized by the highest score [21, 11, 9].", + "bbox": [ + 496, + 500, + 890, + 575 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Evaluation metrics: We report FSS performance using mean Intersection-over-Union (mIoU) and Foreground and Background IoU (FB-IoU), which are widely used by existing methods [16, 31, 13, 21, 11, 9, 22]. We calculate mIoU = $\\frac{1}{n}\\sum_{1}^{n}IoU$ where $n$ is the number of test cases and FB-IoU = $\\frac{1}{2}(IoU_F + IoU_B)$ where $F$ is foreground and $B$ is background without considering classes.", + "bbox": [ + 496, + 577, + 890, + 681 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Results", + "text_level": 1, + "bbox": [ + 500, + 694, + 591, + 709 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "PASCAL-5 $^i$ [5]: Tab. 1 compares the results of the proposed method (MSI) with baseline models on PASCAL-5 $^i$ . MSI allowed almost all experiments to set a new SOTA record. We observed that VAT + MSI provided the most noticeable gains. In the 1-shot test, VAT + MSI provided a $3.0\\%$ gain with ResNet50 and a $2.5\\%$ gain with ResNet101. COCO-20 $^i$ [15]: Tab. 2 reports results on the COCO-20 $^i$ dataset. Our method delivered consistent improvement in almost all experiments. VAT + MSI provided a gain of $5.5\\%$ with ResNet50 [7] and $7.2\\%$ with ResNet101 [7] in mIoU in the 1-shot test, and delivered gains of $5.8\\%$ and $5.6\\%$ in the 5-shot test.", + "bbox": [ + 496, + 718, + 890, + 898 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "19270", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/24886588bd1a304049d62d67717f54418f0b6912386e9aff35f0f40bd8139a78.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
BackboneMethods1-shot5-shot
\\( 5^0 \\)\\( 5^1 \\)\\( 5^2 \\)\\( 5^3 \\)mIoUFB-IoU\\( 5^0 \\)\\( 5^1 \\)\\( 5^2 \\)\\( 5^3 \\)mIoUFB-IoU
ResNet50 [7]CWT [19]56.362.059.947.256.4-61.368.568.556.663.7-
RePRI [1]59.868.362.148.559.7-64.671.471.159.366.6-
CyCTR [36]67.872.858.058.064.2-71.173.260.557.565.6-
BAM [12]69.073.667.661.167.8-70.675.170.867.270.9-
DCAMA [29]67.572.359.659.064.676.770.373.267.467.169.580.6
HSNet [21]64.370.760.360.564.076.770.373.267.467.169.580.6
ASNet [11]68.971.761.162.766.177.772.674.365.367.170.880.4
VAT [8]67.671.262.360.165.377.472.473.668.665.770.080.9
HSNet + MSI68.171.558.262.965.276.570.772.861.566.667.978.2
ASNet + MSI69.271.759.764.466.377.972.073.264.068.069.380.2
VAT + MSI71.072.563.865.968.379.173.074.266.670.571.181.2
ResNet101 [7]CWT [19]56.965.261.248.858.0-62.670.268.857.264.7-
RePRI [1]59.668.662.247.259.4-66.271.467.057.765.6-
CyCTR [36]69.372.756.558.664.372.973.574.058.660.266.675.0
DCAMA [29]65.471.463.258.364.677.670.773.766.861.968.380.8
HSNet [21]67.372.362.063.166.277.671.874.467.068.370.480.6
ASNet [11]69.073.162.063.666.978.073.175.665.769.971.181.0
VAT [8]68.472.564.864.267.578.873.375.268.469.571.682.0
HSNet + MSI70.572.960.664.367.177.871.974.964.167.769.779.5
ASNet + MSI70.573.861.365.567.878.873.475.566.271.071.581.3
VAT + MSI73.173.964.768.870.182.373.676.168.071.372.282.3
", + "bbox": [ + 158, + 88, + 810, + 378 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/2c4276d9b77b9b756ba59afe3df60e3f56194a9b567bab7a797b2fa10268e8f4.jpg", + "table_caption": [ + "Table 1. Performance evaluation on Pascal-5 ${}^{i}$ [5]. Best results are shown in bold." + ], + "table_footnote": [], + "table_body": "
BackboneMethodsI-shot5-shot
200201202203mIoU200201202203mIoU
ResNet50 [7]RePRI [1]32.038.732.733.134.139.345.439.741.841.6
CyCTR [36]38.943.039.639.840.341.148.945.247.045.6
BAM [12]43.450.647.543.446.249.354.251.649.651.2
DCAMA [29]41.945.144.441.743.345.950.550.746.048.3
HSNet [21]36.343.138.738.739.243.351.348.245.046.9
ASNet [11]41.544.142.840.642.247.650.147.746.447.9
VAT [8]39.043.842.639.741.344.151.150.246.147.9
HSNet + MSI40.946.948.845.345.545.353.553.149.350.3
ASNet + MSI41.546.343.542.143.446.050.747.546.947.8
VAT + MSI42.449.249.446.146.847.154.954.151.952.0
ResNet101 [7]DCAMA [29]41.546.245.241.343.548.058.054.347.151.9
HSNet [21]37.244.142.441.341.245.953.051.847.149.5
ASNet [11]41.845.443.241.943.148.052.149.748.249.5
VAT [8]39.544.446.140.442.645.254.151.147.149.4
HSNet + MSI42.450.149.548.347.648.057.352.652.652.6
ASNet + MSI42.945.244.343.444.047.749.949.048.848.9
VAT + MSI44.854.252.348.049.849.358.056.152.754.0
", + "bbox": [ + 127, + 405, + 614, + 625 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/d336867fbe8db5ccb5ba87461c6f5abb91dd82f701c676d37dc0084217f941d9.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
BackboneMethodsmIoU
1-shot5-shot
ResNet50 [7]HSNet [21]85.587.8
VAT [8]89.590.3
HSNet + MSI87.588.4
VAT + MSI90.090.6
ResNet101 [7]HSNet [21]86.588.5
VAT [8]90.090.6
HSNet + MSI88.189.2
VAT + MSI90.691.0
", + "bbox": [ + 620, + 448, + 841, + 568 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/51fbb63bf1042ddfaef9f0b19f06f47964aa7fbc56b1c3d017a666b66ec62aae.jpg", + "table_caption": [ + "Table 3. Performance evaluation on FSS-1000 [14].", + "Table 2. Performance evaluation on COCO- ${20}^{i}$ [15]. Best results are shown in bold." + ], + "table_footnote": [], + "table_body": "
BackboneMethods1-shot mIoU5-shot mIoU
ResNet50 [7]HSNet [21]61.668.7
VAT [8]64.569.7
HSNet + MSI66.070.8
VAT + MSI67.872.6
ResNet101 [7]HSNet [21]64.170.3
VAT [8]66.871.4
HSNet + MSI67.372.3
VAT + MSI69.274.1
", + "bbox": [ + 169, + 661, + 375, + 772 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 4. Generalizability performance evaluation on PASCAL-5 $^i$ [5] after training with COCO-20 $^i$ [15]. Best results are shown in bold.", + "bbox": [ + 76, + 772, + 468, + 811 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "FSS-1000 [14]: Tab. 3 compares the performance of our MSI on FSS-1000 using two baselines: HSNet [21] and VAT [8]. HSNet + MSI delivered $2.0\\%$ and $0.6\\%$ mIoU improvements on 1-shot and 5-shot tests, respectively, with", + "bbox": [ + 76, + 839, + 470, + 902 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "ResNet50 [7]. HSNet + MSI with ResNet101 [7] showed $1.6\\%$ and $0.7\\%$ gains in mIoU. VAT + MSI showed gains of $0.5\\%$ and $0.3\\%$ in mIoU with ResNet50 [7] and gains of $0.3\\%$ and $0.2\\%$ in mIoU with ResNet101 [7].", + "bbox": [ + 500, + 662, + 890, + 724 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Generalization Test: We tested the generalizability of trained models in Tab. 4. HSNet [21] and VAT [8] were compared with HSNet + MSI and VAT + MSI, respectively. Both HSNet + MSI and VAT + MSI delivered significant mIoU gains on 1-shot and 5-shot tests. HSNet + MSI with ResNet50 [7] provided $4.4\\%$ and $2.1\\%$ improvements and VAT + MSI showed $3.4\\%$ and $2.7\\%$ gains.", + "bbox": [ + 498, + 729, + 893, + 835 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Qualitative Results: According to the visual comparison, MSI allows VAT to capture, detailed, accurate, and complete object information, and thus lead to an improved performance and avoid segmenting the wrong object (Fig. 4).", + "bbox": [ + 498, + 839, + 893, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "19271", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/3e3cf6c30f810bfc6bcc8d1c00a57e388a986f359b6033656043c6779f6e257e.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Method & BackboneFMSTFSIFmIoUFB-IoU
VAT (ResNet50)✓60.772.0
✓65.3 (Baseline [8])77.4
✓65.277.4
✓✓66.3 (HM [22])78.0
✓✓68.3 (Ours)79.1
✓✓65.777.5
✓✓✓67.178.8
", + "bbox": [ + 78, + 88, + 468, + 183 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/20376b7e1c3018bfca963d71878252d9caef7cb3fdcfe865e5d642f3f8b7523a.jpg", + "table_caption": [ + "Table 5. Ablation study of the different combination of features with VAT [8] (ResNet50 [7]) on PASCAL-5 $^i$ [5]). $\\checkmark$ denotes that these features are utilized to generate super correlation maps (SCM). The best results are shown in bold." + ], + "table_footnote": [], + "table_body": "
BackboneMethods1-shot
200201202203mIoU
ResNet50 [7]VAT [8] (Baseline)67.671.262.360.165.3
VAT+MSI (Feature Add.)68.571.060.862.065.6
VAT+MSI (Correlation Add.)67.068.253.556.061.2
VAT+MSI (Attention)69.972.563.463.867.4
VAT+MSI (Ours)71.072.563.865.968.3
", + "bbox": [ + 81, + 265, + 464, + 347 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/1a3a143036887b48fb82a1e15106b9eab9842699d5de5600114435303ba25ae3.jpg", + "table_caption": [ + "Table 6. Different methods of generating super correlation maps (SCM) on PASCAL- $5^{i}$ [5]. Best results are shown in bold." + ], + "table_footnote": [], + "table_body": "
BackboneMethods1-shot
200201202203mIoU
ResNet50 (PASCAL-5i)VAT [8]59.942.442.045.547.5
VAT + MSI68.146.643.647.151.4
ResNet50 (COCO-20i)VAT [8]29.732.436.029.031.8
VAT + MSI30.737.940.933.935.9
", + "bbox": [ + 83, + 401, + 464, + 482 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/63fe19040c47858ce93d850e15ede334fbbee0874301367a6d50bc7e5945bcef.jpg", + "table_caption": [ + "Table 7. Performance comparison on PASCAL- $5^{i}$ [5] and COCO $20^{i}$ [15] for cases where support masks occupy below $5\\%$ of the support images. Best results are shown in bold." + ], + "table_footnote": [], + "table_body": "
BackboneMethods1-shot
200201202203mIoU
ResNet50 [7]VAT (w/o person in BG)67.770.961.361.665.2
VAT (w/ person in BG)67.671.262.360.165.3
VAT + MSI (w/o person in BG)69.471.460.564.166.3
VAT + MSI (w/ person in BG)71.072.563.865.968.3
", + "bbox": [ + 83, + 553, + 464, + 621 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 8. Training VAT + MSI on PASCAL-5i[5] without the person class existing as background of the support image.", + "bbox": [ + 76, + 621, + 467, + 648 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Small improvement with ASNet/HSNet: Performance drop in 5-shot is observed on PASCAL with HSNet and ASNet. There could be two reasons. First, both HSNet and ASNet models are limited in fully harnessing MSI's potential. Particularly, ASNet downsamples support features by pooling which loses target information and hence limits the capability of both support target features (STF) and support image features (SIF) in MSI. HSNet lacks self-attention, which would aid MSI by facilitating the network in finding target information from the entire SIF by leveraging STF. Second, ASNet, HSNet, VAT, and their MSI-empowered counterparts are trained for the one-shot setting, which might prevent MSI from specializing in 5-shot testing (Tab 1).", + "bbox": [ + 75, + 688, + 468, + 900 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.2. When is MSI useful?", + "text_level": 1, + "bbox": [ + 500, + 90, + 694, + 104 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "As MSI can better capture target object information, it is more capable of handling challenging FSS scenarios. Fig. 1 draws visual comparisons between $\\mathrm{VAT} + \\mathrm{MSI}$ and the baseline VAT [8] on four challenging FSS cases where MSI is particularly effective. We discuss these cases below. When an instance of the target class is not masked: Fig. 5 visualizes different kinds of features in SIF using $\\mathrm{VAT} + \\mathrm{MSI}$ on PASCAL- $5^{i}$ [5] (ResNet50 [7]). We observe that the support mask fails to mask an instance of the same class, i.e., the sofa on the right side. Therefore, SIF with target features is generated only from the upper sofa. Next, SIF with background features is not very effective overall, even though they better segment the magnified part in the cyan box. Finally, SIF with the entire image's features (ours), which incorporate both the former and the latter features, allows accurate segmentation of the target object, both inside and outside the cyan box. This indicates that background features have target information and utilizing the features improves the performance of FSS.", + "bbox": [ + 496, + 113, + 890, + 400 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Support mask is very small: In PASCAL-5 and COCO-20, there are several cases where the support masks are very small because the target object only occupies a small part of the support image. We compare the mIoU for cases when the support mask occupies less than $5\\%$ of the support image (Tab. 7). Compared to VAT [8], VAT + MSI displays noticeable gains of $3.9\\%$ and $4.1\\%$ (in mIOU) for PASCAL- $5^{i}$ and $\\mathrm{COCO - }20^{i}$ , respectively. These results show that MSI is more effective than the existing methods on very small target objects in both PASCAL- $5^{i}$ [5] and COCO- $20^{i}$ [15].", + "bbox": [ + 496, + 401, + 892, + 551 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Support mask is missing some of the target boundary: We observe that in PASCAL- $5^{i}$ [5], COCO- $20^{i}$ [15], and even FSS-1000 [14], the masks around boundaries can be imperfect (Fig. 6). By masking the features with an inaccurate mask, the boundary information of the target disappears inadvertently (Fig. 6). Therefore, compared to ours, previous methods face difficulties in finding the target in the query image with only limited target information.", + "bbox": [ + 496, + 553, + 890, + 672 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "When some background is helpful: In some FSS cases, the background offers relevant context that is unavailable in the support mask, for accurate segmentation. However, many recent methods depend on support masks to completely remove the background. We notice the person class frequently exists in the background of the support image in PASCAL- $5^{i}$ [5]. Therefore, in order to empirically validate the importance of leveraging relevant background information, we train VAT+MSI and VAT [8] by removing the segmentation mask of the person class when the person exists in the background of the support image. We compare with or without the person class existing in the background of the support image in Tab. 8 and Fig. 7. After excluding the person class, the performance drop for VAT+MSI was much larger than VAT [8].", + "bbox": [ + 496, + 674, + 892, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "19272", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/64eb3229b25a70a9bbc2b302fefdfbdd2c0534c446e0562fe160e23900e35cbd.jpg", + "image_caption": [ + "Figure 4. Visual comparison of VAT [8] and $\\mathrm{VAT} + \\mathrm{MSI}$ with ResNet50 [7] on PASCAL- $5^{i}$ [5] and COCO- $20^{i}$ [15]." + ], + "image_footnote": [], + "bbox": [ + 133, + 88, + 839, + 335 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/3ded2caf7e53ad40f6950aab7234a4669594e64ab86659944fd55857c2a22e3b.jpg", + "image_caption": [ + "Figure 5. Comparison of $\\mathrm{VAT} + \\mathrm{MSI}$ on PASCAL- $5^{i}$ [5] with ResNet50 [7] using different kinds of features in SIF: SIF with only target features, SIF with only background features, and SIF with the entire image's features." + ], + "image_footnote": [], + "bbox": [ + 83, + 380, + 465, + 436 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/3d8b79a81369c5f09c510e00aa14d70d7388d2bc50a9373fb7a9f15e46f34154.jpg", + "image_caption": [ + "Figure 6. Missing information around boundary on PASCAL- $5^{i}$ [5]. The mask is not perfect to cover entire target object." + ], + "image_footnote": [], + "bbox": [ + 81, + 510, + 465, + 584 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/e4e847e66faeb0f675bf271531502790a73088f858dceb8dce241717e69241ed.jpg", + "image_caption": [ + "Figure 7. Comparison of performance when background information of support set is relevant to the background in the query image. Note that the person is in the background of the support image (target object is the ball). VAT failed to segment the ball correctly, while $\\mathrm{VAT} + \\mathrm{MSI}$ was able to differentiate the ball and people." + ], + "image_footnote": [], + "bbox": [ + 78, + 633, + 467, + 703 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.3. Ablation Study and Analysis", + "text_level": 1, + "bbox": [ + 76, + 801, + 333, + 816 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Why the masked support image is helpful: (1) Feature masking (FM) is utilized by several existing FSS models [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12], obtained by masking background features. The target features in FM are not merely targeted object features. When extracting target", + "bbox": [ + 75, + 824, + 468, + 902 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/b8eb9b5cec82d4913a32029aa8017c1e468dcbd1ac248beaf9ce45469dd56077.jpg", + "image_caption": [ + "Figure 8. Feature map comparison between support target features (STF) and feature masking (FM). The cyan circles show that STF captures more fine-grained features near the target object boundary, however, FM struggles to capture the same. In deeper layers, the advantage of STF becomes more apparent (e.g. Block 3)." + ], + "image_footnote": [], + "bbox": [ + 508, + 380, + 880, + 511 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/e90bfa14d07590230f039259dc5abde5aeef00baeaab615ba84a3159f4a09c06.jpg", + "image_caption": [ + "Figure 9. Feature masking (FM) overlooks the impact of the growing receptive field. Background deep features could contain target object information. FM thus loses the detailed target information by masking all features using a support mask. This becomes severe when the support mask is small/inaccurate." + ], + "image_footnote": [], + "bbox": [ + 504, + 601, + 888, + 678 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "features in FM, the features corresponding to background objects could also be present because of the enlarging receptive fields [20]. These background features interfere with obtaining target information. However, this interference can be eliminated by masking the background at the input image level in our MSI. (2) STF holds more target features such as the texture and boundary of the target object than FM. In contrast, FM loses such information by masking features to remove the background (Fig. 8) [22].", + "bbox": [ + 496, + 763, + 892, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "19273", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "How MSI helps for each case: FM is utilized in most FSS works to remove the background in support features [34, 33, 31, 23, 35]. (a) When the support mask fails to mask the same target class in a different location, unlike FM, SIF in MSI can still retain the target information (Fig. 5). (b) When the target class is minuscule, FM features retain minimal target information from masking downstream features (Fig. 9). However, in MSI, we mask support images at the input level. As such, we can retain fine-grained information in STF. Also, SIF could hold the target information missed by STF due to a small mask (Tab. 8). (c) FM loses target boundary information (Fig. 6) when removing background features with an inaccurate mask. However, MSI can overcome this by exploiting additional target information in SIF and it facilitates a network in recovering fine-grained target details through the encoder/decoder. (d) FM cannot utilize the contextual features from the background. For example, if the support and query images have the same non-target object in the background, MSI uses $CS_{1}$ to learn contextual features and recognizes the same objects in QF and SIF, and $CS_{2}$ to find the similarity between STF and QF to learn target-specific features to locate the target object (Fig. 3, Eq. 3). Both $CS_{1}$ and $CS_{2}$ allow the network to recognize non-targets (Fig. 7, Tab. 8) and leverage such information.", + "bbox": [ + 76, + 90, + 472, + 467 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Best features for SCM: In Tab. 5, we show results when using various combinations of features to obtain SCM. For this purpose, VAT [8] with ResNet50 backbone is used as a baseline and PASCAL- $5^{i}$ is chosen for training and testing the model. The ablation study reveals that harnessing both SIF and STF via concatenation achieves the best mIoU. Please see the supplementary text for visualizations of the correlation value distributions for SIF and STF.", + "bbox": [ + 75, + 470, + 468, + 592 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "On different ways of fusing SIF and STF: The proposed method, MSI, calculates cosine similarity between $\\langle$ STF, QF $\\rangle$ and $\\langle$ SIF, QF $\\rangle$ , and concatenates the two generated correlation maps. To see the effectiveness of this method, we experimented with different approaches to fuse SIF and STF to obtain SCM (see Tab. 6). Feature addition refers to the element-wise addition of features before calculating the cosine similarity to get the correlation map. Correlation addition means simply adding two correlation maps elementwise. The attention method merges two correlation maps through 1x1 depth-wise attention based on Attention U-Net [24]. Among all design choices for fusion, concatenating the two correlation maps showed the best performance.", + "bbox": [ + 75, + 595, + 472, + 792 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Fast training convergence: We notice that MSI with VAT [8] and ResNet50 on PASCAL- $5^{i}$ , $\\mathrm{VAT} + \\mathrm{MSI}$ , provides 3.3x faster convergence (i.e. to reach mIoU of $60\\%$ ) on average than VAT (Fig. 10), along with a remarkable improvement in performance. Similarly with HSNet, HSNet+MSI allows faster convergence by 4.5x on average. See supplementary for plots.", + "bbox": [ + 75, + 795, + 470, + 902 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/765c17047fb3bbd89bc616a4bf99967ed550a72caf145878b744cc7a14aefec4.jpg", + "image_caption": [ + "Figure 10. Train. and val. profiles of VAT [8] and $\\mathrm{VAT} + \\mathrm{MSI}$ on PASCAL- $5^{i}$ with ResNet50. $\\mathrm{VAT} + \\mathrm{MSI}$ provides $3.3\\mathrm{x}$ faster convergence (to reach $60\\%$ in mIoU) on average than VAT. Red circles indicate when the training accuracy reaches $60\\%$ in mIoU." + ], + "image_footnote": [], + "bbox": [ + 513, + 90, + 883, + 207 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 291, + 619, + 306 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We proposed a new method, MSI, maximizing the information of the support set, deviating from the masking method [37] widely used in many FSS models [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12]. The joint exploitation of SIF and STF develops a synergy between them, which allows handling several challenging FSS cases. The results show significant performance improvements across all benchmarks on recent, strong FSS baselines (HSNet [21], ASNet [11], and VAT [8]).", + "bbox": [ + 496, + 316, + 893, + 454 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgment", + "text_level": 1, + "bbox": [ + 500, + 467, + 651, + 484 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work is supported in part by NSF Grant #1955404 and #1955365.", + "bbox": [ + 500, + 492, + 890, + 522 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 500, + 537, + 596, + 551 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Malik Boudiaf, Hoel Kervadec, Ziko Imtiaz Masud, Pablo Piantanida, Ismail Ben Ayed, and Jose Dolz. Few-Shot Segmentation Without Meta-Learning: A Good Transductive Inference Is All You Need? In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 13979-13988, June 2021. 6", + "[2] Liang-Chieh Chen, George Papandreou, Iasonas Kokkinos, Kevin Murphy, and Alan L. Yuille. DeepLab: Semantic Image Segmentation with Deep Convolutional Nets, Atrous Convolution, and Fully Connected CRFs. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 40(4):834-848, 2018. 1", + "[3] Seokju Cho, Sunghwan Hong, Sangryul Jeon, Yunsung Lee, Kwanghoon Sohn, and Seungryong Kim. CATs: Cost Aggregation Transformers for Visual Correspondence. In Proceedings of Advances in Neural Information Processing Systems (NeurIPS), 2021. 5", + "[4] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. ImageNet: A large-scale hierarchical image database. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 248–255, 2009. 3, 5", + "[5] Mark Everingham, Luc Van Gool, Christopher Williams, John Winn, and Andrew Zisserman. The Pascal Visual Ob-" + ], + "bbox": [ + 506, + 561, + 893, + 901 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "19274", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "ject Classes (VOC) challenge. International Journal of Computer Vision (IJCV), 88:303-338, 06 2010. 1, 2, 5, 6, 7, 8", + "[6] Xavier Glorot, Antoine Bordes, and Yoshua Bengio. Deep Sparse Rectifier Neural Networks. In Proceedings of the Fourteenth International Conference on Artificial Intelligence and Statistics (AISTAT), volume 15 of Proceedings of Machine Learning Research (PMLR), pages 315-323, Fort Lauderdale, FL, USA, 11-13 Apr 2011. 5", + "[7] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep Residual Learning for Image Recognition. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 770-778, 2016. 3, 5, 6, 7, 8", + "[8] Sunghwan Hong, Seokju Cho, Jisu Nam, and Seungryong Kim. Cost Aggregation Is All You Need for Few-Shot Segmentation. arXiv preprint arXiv:2112.11685, 2021. 2, 3, 5, 6, 7, 8, 9", + "[9] Sunghwan Hong, Seokju Cho, Jisu Nam, Stephen Lin, and Seungryong Kim. Cost Aggregation with 4D Convolutional Swin Transformer for Few-Shot Segmentation. In Proceedings of European Conference on Computer Vision (ECCV), 2022. 1, 2, 3, 4, 5, 8, 9", + "[10] M. Amirul Islam, M. Kowal, S. Jia, K. G. Derpanis, and N. B. Bruce. Global Pooling, More than Meets the Eye: Position Information is Encoded Channel-Wise in CNNs. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 773-781, 2021. 3", + "[11] Dahiyun Kang and Minsu Cho. Integrative Few-Shot Learning for Classification and Segmentation. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 1, 2, 3, 4, 5, 6, 8, 9", + "[12] C. Lang, G. Cheng, B. Tu, and J. Han. Learning what not to segment: A new perspective on few-shot segmentation. In 2022 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 8047-8057, Los Alamitos, CA, USA, jun 2022. IEEE Computer Society. 1, 2, 3, 4, 6, 8, 9", + "[13] Gen Li, Varun Jampani, Laura Sevilla-Lara, Deqing Sun, Jonghyun Kim, and Joongkyu Kim. Adaptive Prototype Learning and Allocation for Few-Shot Segmentation. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2021. 1, 2, 3, 4, 5, 8, 9", + "[14] Xiang Li, Tianhan Wei, Yau Pun Chen, Yu-Wing Tai, and Chi-Keung Tang. FSS-1000: A 1000-Class Dataset for Few-Shot Segmentation. Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2020. 2, 5, 6, 7", + "[15] Tsung-Yi Lin, Michael Maire, Serge Belongie, Lubomir Bourdev, Ross Girshick, James Hays, Pietro Perona, Deva Ramanan, C. Lawrence Zitnick, and Piotr Dólar. Microsoft COCO: Common Objects in Context. In Proceedings of European Conference on Computer Vision (ECCV), 2014. 1, 2, 5, 6, 7, 8", + "[16] Weide Liu, Chi Zhang, Henghui Ding, Tzu-Yi Hung, and Guosheng Lin. Few-shot Segmentation with Optimal Transport Matching and Message Flow. IEEE Transactions on Multimedia (TMM), 2022. 1, 2, 4, 5" + ], + "bbox": [ + 78, + 90, + 470, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[17] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin Transformer: Hierarchical Vision Transformer using Shifted Windows. In Proceedings of International Conference on Computer Vision (ICCV), 2021. 3", + "[18] J. Long, E. Shelhamer, and T. Darrell. Fully convolutional networks for semantic segmentation. In 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3431-3440, Los Alamitos, CA, USA, jun 2015. IEEE Computer Society. 1", + "[19] Zhihe Lu, Sen He, Xiatian Zhu, Li Zhang, Yi-Zhe Song, and Tao Xiang. Simpler is Better: Few-shot Semantic Segmentation with Classifier Weight Transformer. In Proceedings of International Conference on Computer Vision (ICCV), 2021. 1, 2, 6", + "[20] Wenjie Luo, Yujia Li, Raquel Urtasun, and Richard Zemel. Understanding the effective receptive field in deep convolutional neural networks. In Proceedings of the 30th International Conference on Neural Information Processing Systems, NIPS'16, page 4905-4913, Red Hook, NY, USA, 2016. Curran Associates Inc. 4, 8", + "[21] Juhong Min, Dahiyun Kang, and Minsu Cho. Hypercorrelation Squeeze for Few-Shot Segmentation. In Proceedings of International Conference on Computer Vision (ICCV), pages 6941-6952, 2021. 1, 2, 3, 4, 5, 6, 8, 9", + "[22] Seonghyeon Moon, Samuel S. Sohn, Honglu Zhou, Sejong Yoon, Vladimir Pavlovic, Muhammad Haris Khan, and Mubasir Kapadia. HM: Hybrid Masking for Few-Shot Segmentation. In Proceedings of European Conference on Computer Vision (ECCV), pages 506-523, 2022. 1, 2, 3, 4, 5, 7, 8", + "[23] Khoi Nguyen and Sinisa Todorovic. Feature Weighting and Boosting for Few-Shot Segmentation. In Proceedings of International Conference on Computer Vision (ICCV), 2019, 1, 2, 3, 4, 8, 9", + "[24] Ozan Oktay, Jo Schlemper, Loic Le Folgoc, Matthew C. H. Lee, Mattias P. Heinrich, Kazunari Misawa, Kensaku Mori, Steven G. McDonagh, Nils Y. Hammerla, Bernhard Kainz, Ben Glocker, and Daniel Rueckert. Attention U-Net: Learning Where to Look for the Pancreas. In Medical Imaging with Deep Learning (MIDL), 2018. 5, 9", + "[25] Kate Rakelly, Evan Shelhamer, Trevor Darrell, Alyosha A. Efros, and Sergey Levine. Conditional Networks for Few-Shot Semantic Segmentation. In Workshop Track Proceedings of International Conference on Learning Representations (ICLR), 2018. 1, 2", + "[26] Joseph Redmon, Santosh Divvala, Ross Girshick, and Ali Farhadi. You only look once: Unified, Real-time Object Detection. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 779-788, 2016. 1", + "[27] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster R-CNN: Towards Real-time Object Detection with Region Proposal Networks. Proceedings of Advances in Neural Information Processing Systems (NeurIPS), 28, 2015. 1", + "[28] Amirreza Shaban, Shray Bansal, Zhen Liu, Irfan Essa, and Byron Boots. One-Shot Learning for Semantic Segmenta" + ], + "bbox": [ + 501, + 92, + 893, + 901 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "19275", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "tion. In Proceedings of British Machine Vision Conference (BMVC), pages 167.1-167.13, 2017. 2, 4", + "[29] Xinyu Shi, Dong Wei, Yu Zhang, Donghuan Lu, Munan Ning, Jiashun Chen, Kai Ma, and Yefeng Zheng. Dense cross-query-and-support attention weighted mask aggregation for few-shot segmentation. In Computer Vision - ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XX, page 151-168, 2022. 3, 6", + "[30] Mennatullah Siam, Boris N. Oreshkin, and Martin Jägersand. AMP: Adaptive Masked Proxies for Few-Shot Segmentation. In Proceedings of International Conference on Computer Vision (ICCV), pages 5248-5257, 2019. 1, 2", + "[31] Zhuotao Tian, Hengshuang Zhao, Michelle Shu, Zhicheng Yang, Ruiyu Li, and Jiaya Jia. Prior Guided Feature Enrichment Network for Few-Shot Segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 2020. 1, 2, 3, 4, 5, 8, 9", + "[32] Haochen Wang, Xudong Zhang, Yutao Hu, Yandan Yang, Xianbin Cao, and Xiantong Zhen. Few-Shot Semantic Segmentation with Democratic Attention Networks. In Proceedings of European Conference on Computer Vision (ECCV), pages 730-746, 2020. 1, 2", + "[33] Kaixin Wang, Jun Hao Liew, Yingtian Zou, Daquan Zhou, and Jiashi Feng. PANet: Few-Shot Image Semantic Segmentation With Prototype Alignment. In Proceedings of International Conference on Computer Vision (ICCV), 2019, 1, 2, 3, 4, 8, 9", + "[34] Boyu Yang, Chang Liu, Bohao Li, Jianbin Jiao, and Ye Qixiang. Prototype Mixture Models for Few-shot Semantic Segmentation. In Proceedings of European Conference on Computer Vision (ECCV), 2020. 1, 2, 3, 4, 8, 9", + "[35] Chi Zhang, Guosheng Lin, Fayao Liu, Rui Yao, and Chunhua Shen. CANet: Class-Agnostic Segmentation Networks With Iterative Refinement and Attentive Few-Shot Learning. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2019. 1, 2, 3, 4, 8, 9", + "[36] Gengwei Zhang, Guoliang Kang, Yi Yang, and Yunchao Wei. Few-Shot Segmentation via Cycle-Consistent Transformer. arXiv preprint arXiv:2106.02320, 2021. 2, 3, 4, 6, 8, 9", + "[37] Xiaolin Zhang, Yunchao Wei, Yi Yang, and Thomas Huang. SG-One: Similarity Guidance Network for One-Shot Semantic Segmentation. IEEE Transactions on Cybernetics, 50:3855-3865, 2020. 1, 2, 3, 4, 9", + "[38] Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, and Jiaya Jia. Pyramid Scene Parsing Network. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 6230-6239, 2017. 1" + ], + "bbox": [ + 78, + 90, + 470, + 782 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "19276", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/18b3712a-f7d6-4a6b-8811-754fd084ad1d_model.json b/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/18b3712a-f7d6-4a6b-8811-754fd084ad1d_model.json new file mode 100644 index 0000000000000000000000000000000000000000..e0d0246f4a667724793d73233362d3ec37b112a7 --- /dev/null +++ b/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/18b3712a-f7d6-4a6b-8811-754fd084ad1d_model.json @@ -0,0 +1,2103 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.138, + 0.131, + 0.834, + 0.154 + ], + "angle": 0, + "content": "MSI: Maximize Support-Set Information for Few-Shot Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.15, + 0.182, + 0.305, + 0.217 + ], + "angle": 0, + "content": "Seonghyeon Moon\nRutgers University" + }, + { + "type": "text", + "bbox": [ + 0.147, + 0.22, + 0.309, + 0.233 + ], + "angle": 0, + "content": "sm2062@rutgers.edu" + }, + { + "type": "text", + "bbox": [ + 0.384, + 0.182, + 0.533, + 0.218 + ], + "angle": 0, + "content": "Samuel S. Sohn \nRutgers University" + }, + { + "type": "text", + "bbox": [ + 0.355, + 0.221, + 0.56, + 0.234 + ], + "angle": 0, + "content": "samuel.sohn@rutgers.edu" + }, + { + "type": "text", + "bbox": [ + 0.604, + 0.182, + 0.824, + 0.216 + ], + "angle": 0, + "content": "Honglu Zhou \nNEC Laboratories America" + }, + { + "type": "text", + "bbox": [ + 0.628, + 0.221, + 0.8, + 0.233 + ], + "angle": 0, + "content": "hozhou@nec-labs.com" + }, + { + "type": "text", + "bbox": [ + 0.31, + 0.243, + 0.416, + 0.26 + ], + "angle": 0, + "content": "Sejong Yoon" + }, + { + "type": "text", + "bbox": [ + 0.256, + 0.261, + 0.471, + 0.278 + ], + "angle": 0, + "content": "The College of New Jersey" + }, + { + "type": "text", + "bbox": [ + 0.299, + 0.281, + 0.427, + 0.294 + ], + "angle": 0, + "content": "yoons@tcnj.edu" + }, + { + "type": "text", + "bbox": [ + 0.55, + 0.243, + 0.7, + 0.278 + ], + "angle": 0, + "content": "Vladimir Pavlovic \nRutgers University" + }, + { + "type": "text", + "bbox": [ + 0.535, + 0.28, + 0.714, + 0.294 + ], + "angle": 0, + "content": "vladimir@rutgers.edu" + }, + { + "type": "text", + "bbox": [ + 0.114, + 0.303, + 0.566, + 0.338 + ], + "angle": 0, + "content": "Muhammad Haris Khan \nMohamed Bin Zayed University of Artificial Intelligence" + }, + { + "type": "text", + "bbox": [ + 0.218, + 0.341, + 0.461, + 0.354 + ], + "angle": 0, + "content": "muhammad.haris@mbzuai.ac.ae" + }, + { + "type": "text", + "bbox": [ + 0.655, + 0.303, + 0.806, + 0.338 + ], + "angle": 0, + "content": "Mubbasir Kapadia \nRutgers University" + }, + { + "type": "text", + "bbox": [ + 0.605, + 0.341, + 0.855, + 0.355 + ], + "angle": 0, + "content": "mubbasir.kapadia@rutgers.edu" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.39, + 0.313, + 0.406 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.422, + 0.474, + 0.709 + ], + "angle": 0, + "content": "FSS (Few-shot segmentation) aims to segment a target class using a small number of labeled images (support set). To extract information relevant to the target class, a dominant approach in best performing FSS methods removes background features using a support mask. We observe that this feature excision through a limiting support mask introduces an information bottleneck in several challenging FSS cases, e.g., for small targets and/or inaccurate target boundaries. To this end, we present a novel method (MSI), which maximizes the support-set information by exploiting two complementary sources of features to generate super correlation maps. We validate the effectiveness of our approach by instantiating it into three recent and strong FSS methods. Experimental results on several publicly available FSS benchmarks show that our proposed method consistently improves performance by visible margins and leads to faster convergence. Our code and trained models are available at: https://github.com/moonsh/MSI-Maximize-Support-Set-Information" + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.739, + 0.21, + 0.755 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Deep convolutional neural networks (DCNNs) have achieved state-of-the-art results across several mainstream computer vision (CV) problems, including object detection [26, 27] and semantic segmentation [18, 2, 38]. An important factor underlying the success of DCNNs is large-scale annotated datasets, which are costly and cumbersome to acquire in many dense prediction tasks, such as semantic segmentation. Moreover, these models struggle to segment novel objects when only a few annotated examples are" + }, + { + "type": "text", + "bbox": [ + 0.52, + 0.419, + 0.535, + 0.43 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "image", + "bbox": [ + 0.545, + 0.39, + 0.871, + 0.626 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.63, + 0.895, + 0.81 + ], + "angle": 0, + "content": "Figure 1. Recent FSS baseline (VAT[9]) struggles to accurately segment the target object in several challenging scenarios in PASCAL [5] and \\(\\mathrm{COCO}^i\\) [15]: (a) the same instance of the target class is not masked, e.g., the sofa on the right, (b) the support mask is very small compared to the entire image, e.g., flowers in the pot, (c) support mask is missing some target boundary information, e.g., the front and chimney of the train, and (d) the background contains some important contextual information, unavailable in the support mask, e.g., shoes and grass. Our method (MSI) is capable of accurately segmenting target objects. It maximizes the support set information to compensate for the limited support mask information and can exploit relevant contextual information from the background." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.84, + 0.894, + 0.903 + ], + "angle": 0, + "content": "available. Many existing few-shot segmentation (FSS) approaches [25, 30, 34, 23, 31, 33, 35, 13, 32, 16, 37, 19, 21, 11, 12, 9, 22] aim to address this shortcoming. The problem settings in FSS require accurate segmentation of a target ob" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "19266" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.102, + 0.09, + 0.422, + 0.187 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.1, + 0.192, + 0.45, + 0.287 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.101, + 0.293, + 0.45, + 0.387 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.391, + 0.47, + 0.502 + ], + "angle": 0, + "content": "Figure 2. (a) Many FSS methods use support mask to remove background features [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12], denoted as feature masking (FM), and so rely only on target object features. (b) Recent work, HM [22], merges both image masking and feature masking to achieve hybrid masking for improving target information. (c) We propose to maximize the support set information (MSI) to compensate for the limited support mask information and exploit relevant contextual information from the background." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.533, + 0.468, + 0.563 + ], + "angle": 0, + "content": "ject in a query image, given few annotated images, termed the support set, from the target class." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.566, + 0.468, + 0.806 + ], + "angle": 0, + "content": "Shaban et al.'s work [28] introduced the first FSS model, in which a masked support image was used to extract only the target features. Using the target features, both segmentation and conditioning branches are trained to segment an object of the target class. Later, Zhang et al. [37] show that extracting target features using masked average pooling (MAP) is more beneficial for network learning than obtaining features by masking images. Since then, many FSS models [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12] have considered MAP as the de facto technique for obtaining target features and focus on improving the encoder/decoder network. Recently, HSNet [21] proposed to utilize more effective target features extracted from multiple layers of a deep backbone network. Likewise, ASNet [11] and VAT [9] proposed different network architectures to harness deep features." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Despite promising results, many recent methods, including HSNet [21], ASNet [11], and VAT [9], systematically struggle with few challenging FSS cases (Fig. 1): (a) When the support mask does not mask all instances of the same target class; (b) The support mask is unable to faithfully capture object boundaries; (c) The support mask is too" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.198 + ], + "angle": 0, + "content": "small, carrying limited object information; and (d) The background contains some important contextual information, unavailable in the support mask, for accurately segmenting the target object. We conjecture that this happens because many current SOTA methods rely on support masks to completely remove the background (Fig. 2), which limits the useful information in several challenging FSS cases." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.199, + 0.892, + 0.452 + ], + "angle": 0, + "content": "In this paper, we propose a new method to overcome the limited information bottleneck from the support mask. It is based on the intuition that upon maximizing the information from the masked support set images (MSI), it is possible to compensate for the limited support mask information by utilizing the important contextual information available in the typically discarded background (Fig. 2). MSI jointly exploits two complementary sources of features. The first set of features is obtained by using masked support images, which only activate the target-related features in the query image. The second set of features is generated from the full support images, which activate the features of all similar objects shared between the support and query images. The former features act as an anchor for the latter in localizing a certain target class while supplementing it with the target boundary information. We summarize our key contributions as follows:" + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.454, + 0.892, + 0.529 + ], + "angle": 0, + "content": "- We propose MSI, an efficient and effective plug-and-play module for FSS methods. MSI harnesses masked support images to capture the delineated target information and exploits the entire support image for complete target information." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.53, + 0.892, + 0.62 + ], + "angle": 0, + "content": "- We perform extensive experiments and analysis on three challenging FSS benchmarks: PASCAL-\\(5^{i}\\) [5], COCO-\\(20^{i}\\) [15], and FSS-1000 [14]. Results show that MSI consistently improves mIoU in the one-shot setting over all strong baselines, including HSNet [21], ASNet [11], and VAT [9]." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.62, + 0.892, + 0.665 + ], + "angle": 0, + "content": "- MSI improves the training speed of recent baseline models on PASCAL-5\\(^i\\) [5], with 3.3x average speed-up on VAT [8] and 4.5x on HSNet [21]." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.454, + 0.892, + 0.665 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.68, + 0.649, + 0.695 + ], + "angle": 0, + "content": "2. Related Works" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.892, + 0.795 + ], + "angle": 0, + "content": "Few-shot segmentation: OSLSM [28] is considered to be the first work introducing FSS problem. OSLSM proposed a model consisting of a condition branch and a segmentation branch. Since OSLSM, various methods have been proposed to solve the FSS problem [25, 30, 34, 23, 31, 33, 35, 13, 32, 16, 37, 19, 21, 11, 12, 9, 22]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.892, + 0.901 + ], + "angle": 0, + "content": "MAP (Masked Average Pooling): Zhang et al. [37] proposed the MAP to collect target information from the support set. MAP masks features instead of masking support images and uses average pooling to extract target information. They argued that (1) removing the background from support images increases the variance of the input data for a unified network and (2) masking the im" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "19267" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.242 + ], + "angle": 0, + "content": "age will make the network biased toward the target image. For these reasons, MAP was recommended to get target features. Since Zhang et al. [37], many few shot works [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12] are following MAP to extract target features. However, by performing average pooling, spatial information is inevitably lost [10]. In this work, we utilized the masked support image to generate target features without using MAP. Therefore, we can retrieve fine-detail texture information and preserve spatial information." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.245, + 0.473, + 0.488 + ], + "angle": 0, + "content": "Multi-layer features: Instead of using MAP, HSNet [21] proposed to use deep features extracted from multiple layers and designed an effective convolution to process the features. To process the deep features effectively and efficiently, VAT [8] proposed a model based on the swim transformer [17] and ASNet [11] proposed the attentive squeeze network. HM [22] proposed hybrid masking to compensate for the lost details in feature masking. Although the spatial information that MAP lost was preserved, these works extracted target features counting on support masks. Therefore, when the support masks give limited information, limited target information is extracted. In this paper, not only is information loss minimized when the target features are extracted by relying on the support mask, but also more meaningful target features are extracted by utilizing both the entire support image and the masked support image." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.49, + 0.473, + 0.779 + ], + "angle": 0, + "content": "Utilizing background information: There have been several attempts to improve FSS accuracy by using background information [34, 12]. PMM [34] proposed a method of deactivating the background and activating the target object using a duplex manner. Negative learning was carried out with objects in the background, and on the other hand, positive learning was conducted using the foreground object. Afterward, the two learning results were used to segment the target object accurately. Similarly, BAM [12] also proposed to use two learners. The base learner was trained using objects in the background and a meta learner was trained with the foreground object. These two learners were integrated to predict segmentation accurately. However, they assumed that the background lacks meaningful target information. Therefore, they missed target information that might exist in the background. We obtain even more target information from the background and simultaneously utilize background information to avoid segmenting wrong objects." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Cross attention: Both CyCTR [36] and DCAMA [29] utilize the transformer architecture to achieve cross-attention between the support and query features. This cross-attention allows the identification of target information beyond the mask area. Despite this, both methods rely on an unmasked support image to extract target information, leading to the loss of delineated detailed target information. On the contrary, MSI proposes to directly provide the model" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.895, + 0.213 + ], + "angle": 0, + "content": "with features from the masked support image and the full support image, thereby introducing a strong inductive bias that ultimately leads to better performance. MSI computes the cosine similarity between these two complementary sets of features and concatenates them. Therefore, MSI can retain detailed target information. It is more intuitive and simpler and can be plugged seamlessly into various FSS baselines, as validated in our experiments." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.224, + 0.66, + 0.24 + ], + "angle": 0, + "content": "3. Overall Method" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.249, + 0.895, + 0.553 + ], + "angle": 0, + "content": "Fig. 3 displays the overall architecture of our method. Following recent works [21, 11, 9], it consists of a backbone network (ResNet-50 [7] or ResNet-101 [7]) pre-trained on ImageNet [4] to obtain multi-layer features, and an encoder/decoder network to predict the segmentation mask. We propose a new plug-and-play module to maximize the support set information (MSI), which compensates for limited support mask information by exploiting relevant contextual information from the background. MSI extracts support target features (STF), containing delineated target class information from the support images, and support image features (SIF), accounting for the information in the entire support image. Next, STF and SIF are leveraged to obtain their respective correlation maps by computing the cosine similarity with respect to the query features (QF) obtained from the query image. Then, the correlation maps corresponding to STF and SIF are utilized to get super correlation maps (SCM). Finally, this SCM is used as the input to the encoder and decoder which can be from recent FSS methods (e.g., [21], [9], and [11])." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.56, + 0.642, + 0.575 + ], + "angle": 0, + "content": "3.1. Preliminaries" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.583, + 0.894, + 0.658 + ], + "angle": 0, + "content": "The goal of few-shot segmentation is to train a model that can segment the target object in a query image when provided with a few annotated example images from the target class. Following prior work in FSS [21, 11, 9], we utilize the episodic scheme for training our model." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.659, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Specifically, we assume the availability of two disjoint sets, \\( C_{train} \\) and \\( C_{test} \\) as training and testing classes, respectively. The training data \\( D_{train} \\) is sampled from \\( C_{train} \\) and the testing data \\( D_{test} \\) is from \\( C_{test} \\). We then construct multiple episodes from \\( D_{train} \\) and \\( D_{test} \\). An episode is comprised of a support set, \\( S = (I^s, M^s) \\), and a query set, \\( Q = (I^q, M^q) \\), where \\( I^* \\) and \\( M^* \\) denote an image and its corresponding mask. Furthermore, \\( D_{train} = \\{(S_i, Q_i)\\}_{i=1}^{N_{train}} \\) and \\( D_{test} = \\{(S_i, Q_i)\\}_{i=1}^{N_{test}} \\), where \\( N_{train} \\) represents the number of episodes for training and \\( N_{test} \\) is the number of episodes for testing. During training, we iteratively sample episodes from \\( D_{train} \\) to train a model that learns a mapping from \\( (I^s, M^s, I^q) \\) to query mask \\( M^q \\). The learned model is used without further optimization by randomly sampling episodes from the testing data \\( D_{test} \\) in the same manner and comparing the predicted query masks to the ground truth." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19268" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.148, + 0.089, + 0.638, + 0.276 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.651, + 0.09, + 0.824, + 0.275 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.28, + 0.892, + 0.378 + ], + "angle": 0, + "content": "Figure 3. Overall architecture. To maximize the usability of the support set, first we extract support image features (SIF) and support target features (STF) through the backbone. SIF branch creates features using the entire support image, and STF branch extracts the features after removing background pixels. The query features (QF) are obtained from the query. We obtain correlation maps by calculating the cosine similarity (CS) of the STF and SIF with the QF, respectively, and these correlation maps are concatenated to make super correlation maps (SCM). \\( CS_2 \\) represents the cosine similarity between the target object and the query image. Therefore, only target-related information in the query image will be activated. \\( CS_1 \\), on the other hand, assesses the cosine similarity between the entire support image and the query image. Consequently, all the similar objects between the support image and the query image are activated." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.402, + 0.446, + 0.417 + ], + "angle": 0, + "content": "3.2. Maximizing Support-Set Information: MSI" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.428, + 0.468, + 0.639 + ], + "angle": 0, + "content": "An important question for the FSS pipeline is where in a network it is most suitable to use masking to provide target information to the network. Earlier attempts, such as the work of Shaban et al. [28] suggested masking the background in the input image so that only target features are obtained. The rationale was that the network would supposedly be biased toward large objects, so removing the background would decrease the variance of the output parameters. Later, Zhang et al. [37] proposed to mask the background after extracting features because masking the input image makes a network biased towards the target image and changes the statistical distribution of the support image set. Many recent state-of-the-art methods have conformed to this approach [34, 33, 31, 23, 35, 16, 13, 36, 21, 9, 11, 12]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.642, + 0.468, + 0.808 + ], + "angle": 0, + "content": "Motivation: Although these methods report promising performance, we note that many recent methods, including HSNet [21], ASNet [11], and VAT [9], struggle to accurately predict the segmentation mask in several challenging scenarios (Fig. 1). We believe that this occurs because many recent FSS methods fully rely on the support mask to remove the background features (Fig. 2). These support masks likely present an information bottleneck in such challenging cases. For instance, when they are very small, they fail to properly encapsulate target object boundaries or do not capture all instances of the target object." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.468, + 0.901 + ], + "angle": 0, + "content": "We put forth a new approach (MSI) to alleviate the aforementioned limitations of support masks. We believe that by maximizing the information from support images, it becomes possible to compensate for the limited information in the support mask and also leverage important contextual information available in the background. Specifically, we" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.402, + 0.892, + 0.688 + ], + "angle": 0, + "content": "extract support target features (STF), which contain delineated target class information in the support image, and support image features (SIF), which contain contextualized information from the entire support image. This is because the STF enables the acquisition of more focused and fine-grained target information, and compared to feature masking (Fig. 2) STF captures more accurate object boundaries because the receptive field can cover even the area beyond target object at deep features [20, 22]. On the other hand, SIF utilizes the full support image to capture relevant and useful target information that exists in the background. This allows us to obtain both detailed and complete information about the target class to avoid segmenting wrong objects. We leverage STF and SIF to obtain their respective correlation maps by computing their cosine similarity with the query features (QF), which are obtained from the query image. The correlation maps corresponding to STF and SIF are then combined into Super Correlation Maps (SCM), which are inputted to the encoder and decoder." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.69, + 0.892, + 0.796 + ], + "angle": 0, + "content": "Formalizing STF and SIF: Support image features (SIF), \\(\\alpha_{i=1}^{N}\\), where \\(N\\) is the number of features, refer to the features of the entire support image, \\(I^{S} \\in \\mathbb{R}^{3 \\times w \\times h}\\), where \\(w\\) is the width and \\(h\\) is the height of the image. Support target features (STF), \\(\\beta_{i=1}^{N}\\), are the features from the target image, \\(I^{T} \\in \\mathbb{R}^{3 \\times w \\times h}\\), which is a masked support image using support mask \\(\\mathbf{M}^{S} \\in \\{0,1\\}^{w \\times h}\\). Formally," + }, + { + "type": "equation", + "bbox": [ + 0.628, + 0.807, + 0.891, + 0.826 + ], + "angle": 0, + "content": "\\[\nI ^ {T} = I ^ {S} \\odot \\zeta (M ^ {S}), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.899 + ], + "angle": 0, + "content": "where \\(\\zeta (\\cdot)\\) resizes the mask \\(M^S\\) to fit the dimension of the image \\(I^{S}\\) and \\(\\odot\\) denotes the Hadamard product. Query features (QF), \\(\\kappa_{i = 1}^{N}\\) , are obtained from the query image, \\(I^Q\\in \\mathbb{R}^{3\\times w\\times h}\\)" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.956 + ], + "angle": 0, + "content": "19269" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.078, + 0.091, + 0.47, + 0.138 + ], + "angle": 0, + "content": "For each image \\((I^S, I^T, \\text{and} I^Q)\\), the backbone network, \\(\\triangleleft\\), produces \\(N\\) number of features \\((\\alpha_{i=1}^N, \\beta_{i=1}^N, \\text{and} \\kappa_{i=1}^N\\) respectively) from its intermediate layers." + }, + { + "type": "equation", + "bbox": [ + 0.101, + 0.146, + 0.47, + 0.169 + ], + "angle": 0, + "content": "\\[\n\\alpha_ {i = 1} ^ {N} = \\triangleleft (I ^ {S}), \\beta_ {i = 1} ^ {N} = \\triangleleft (I ^ {T}), \\kappa_ {i = 1} ^ {N} = \\triangleleft (I ^ {Q}), (2)\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.177, + 0.469, + 0.237 + ], + "angle": 0, + "content": "where features, \\(\\alpha_{i},\\beta_{i},\\kappa_{i}\\in \\mathbb{R}^{c_{i}\\times w_{i}\\times h_{i}}\\) , have different sizes of channel and spatial dimensions. Features extracted from deeper layers have a large number of channels with smaller width and height dimensions." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.238, + 0.469, + 0.349 + ], + "angle": 0, + "content": "Super Correlation Maps (SCM): We calculate the cosine similarities of \\(\\alpha_{i=1}^{N}\\) and \\(\\beta_{i=1}^{N}\\) with respect to \\(\\kappa_{i=1}^{N}\\) using the Eq. 3 to get correlation maps \\(C_i \\in \\mathbb{R}^{1 \\times w_i \\times h_i \\times w_i \\times h_i}\\) and \\(S_i \\in \\mathbb{R}^{1 \\times w_i \\times h_i \\times w_i \\times h_i}\\). To perform multiplication between features, we reshape and transpose the features, \\(\\alpha_{i=1}^{N}, \\beta_{i=1}^{N}\\), and \\(\\kappa_{i=1}^{N}\\) into \\(\\alpha_{i=1}^{\\prime N} \\in \\mathbb{R}^{(w_i \\cdot h_i) \\times c_i}\\), \\(\\beta_{i=1}^{\\prime N} \\in \\mathbb{R}^{(w_i \\cdot h_i) \\times c_i}\\), and \\(\\kappa_{i=1}^{\\prime N} \\in \\mathbb{R}^{c_i \\times (w_i \\cdot h_i)}\\)." + }, + { + "type": "equation", + "bbox": [ + 0.126, + 0.358, + 0.469, + 0.402 + ], + "angle": 0, + "content": "\\[\nC S _ {1} = C _ {i = 1} ^ {N} = \\operatorname {R e L U} \\left(\\frac {\\alpha_ {i = 1} ^ {\\prime N} \\cdot \\kappa_ {i = 1} ^ {\\prime N}}{\\| \\alpha_ {i = 1} ^ {\\prime N} \\| \\| \\kappa_ {i = 1} ^ {\\prime N} \\|}\\right), \\tag {3}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.129, + 0.398, + 0.419, + 0.436 + ], + "angle": 0, + "content": "\\[\nC S _ {2} = S _ {i = 1} ^ {N} = \\mathrm {R e L U} \\bigg (\\frac {\\beta_ {i = 1} ^ {\\prime N} \\cdot \\kappa_ {i = 1} ^ {\\prime N}}{\\| \\beta_ {i = 1} ^ {\\prime N} \\| \\| \\kappa_ {i = 1} ^ {\\prime N} \\|} \\bigg),\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.444, + 0.469, + 0.522 + ], + "angle": 0, + "content": "where \\(N\\) the is number of features and ReLU [6] removes inactivated and noisy values in the correlation map \\(C_i\\) and \\(S_{i}\\). Correlation maps \\(C_{i = 1}^{N}\\) and \\(S_{i = 1}^{N}\\) are concatenated along the first dimension to obtain the Super Correlation Maps (SCM), \\(P_{i = 1}^{N}\\in \\mathbb{R}^{2\\times w_{i}\\times h_{i}\\times w_{i}\\times h_{i}}\\) (Eq. 4)." + }, + { + "type": "equation", + "bbox": [ + 0.163, + 0.529, + 0.47, + 0.55 + ], + "angle": 0, + "content": "\\[\nS C M = P _ {i = 1} ^ {N} = \\left[ C _ {i = 1} ^ {N} \\oplus S _ {i = 1} ^ {N} \\right], \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.559, + 0.316, + 0.573 + ], + "angle": 0, + "content": "where \\(\\oplus\\) denotes the concatenation." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.583, + 0.383, + 0.598 + ], + "angle": 0, + "content": "3.3. Encoder and Decoder Architecture" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.606, + 0.469, + 0.757 + ], + "angle": 0, + "content": "SCM can be fed as input to any encoder and decoder architecture of FSS methods. In order to validate our proposed method, we experiment with feeding SCM as input to three recent and strong encoder-decoder based FSS methods: HSNet [21], ASNet [11], and VAT [8]. For HSNet and VAT, the input channel size of the encoder in the models was doubled. For ASNet, SCM is merged using depth-wise attention based on Attention U-Net [24] instead of changing the input channel size. Otherwise, the architectures of the models were unchanged." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.77, + 0.21, + 0.787 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.795, + 0.469, + 0.901 + ], + "angle": 0, + "content": "Datasets: We use three widely used and publicly available datasets for evaluating our method (MSI): PASCAL- \\(5^{i}\\) [5], COCO- \\(20^{i}\\) [15] and FSS-1000 [14]. PASCAL- \\(5^{i}\\) consists of 20 classes, whereas COCO- \\(20^{i}\\) has 100 classes and FSS-1000 contains 1000 classes. Following previous works [21, 11, 9], we cross validate using 4 folds for PASCAL- \\(5^{i}\\) and COCO- \\(20^{i}\\) and we divide the classes into 4" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.242 + ], + "angle": 0, + "content": "groups for training and testing. Therefore, 5 and 20 classes are used for each fold testing on PASCAL- \\(5^{i}\\) and COCO\\(20^{i}\\), respectively. Other remaining classes are used for training. For FSS-1000, 1000 classes are divided into 520, 240 and 240 for the training, validation and testing. Lastly, in order to evaluate the generalizability of our method, COCO\\(20^{i}\\) is used for training, and PASCAL- \\(5^{i}\\) for testing. To avoid class overlapping between training and testing, following previous works [21, 31], we change the PASCAL- \\(5^{i}\\) class order for each fold." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.243, + 0.893, + 0.499 + ], + "angle": 0, + "content": "Implementation details: We incorporate MSI into three baseline models, HSNet [21], VAT [8], and ASNet [11], and refer to them as HSNet + MSI, ASNet + MS and VAT + MSI. The backbone networks, ResNet50 [7] and ResNet101 [7], are pre-trained on ImageNet [4], and are used to extract deep features following HSNet, ASNet, and VAT (features from conv3_x to conv5_x before the ReLU [6] activation of each layer stacked to form the deep features). No fine-tuning of backbones was performed. For a fair comparison with the existing models, we keep their default hyperparameters, as listed in their codebases. For VAT training, CATs data augmentation [3] was used and the batch size was reduced due to GPU memory limitations. Specifically, the batch sizes 4, 8, and 4 were used for PASCAL\\(^{5^i}\\) [5], COCO-20\\(^{i}\\) [15], and FSS-1000 [14] respectively. No data augmentation was employed for training HSNet + MSI and ASNet + MSI." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.501, + 0.892, + 0.576 + ], + "angle": 0, + "content": "Super-correlation maps for K-Shots>1: Given a query image and K support-set images, we compute SCM for each query-support pair, resulting in K SCMs and K corresponding mask predictions from the model. All predictions are summed and normalized by the highest score [21, 11, 9]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.578, + 0.892, + 0.683 + ], + "angle": 0, + "content": "Evaluation metrics: We report FSS performance using mean Intersection-over-Union (mIoU) and Foreground and Background IoU (FB-IoU), which are widely used by existing methods [16, 31, 13, 21, 11, 9, 22]. We calculate mIoU = \\(\\frac{1}{n}\\sum_{1}^{n}IoU\\) where \\(n\\) is the number of test cases and FB-IoU = \\(\\frac{1}{2}(IoU_F + IoU_B)\\) where \\(F\\) is foreground and \\(B\\) is background without considering classes." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.695, + 0.593, + 0.71 + ], + "angle": 0, + "content": "4.1. Results" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.719, + 0.892, + 0.9 + ], + "angle": 0, + "content": "PASCAL-5\\(^i\\) [5]: Tab. 1 compares the results of the proposed method (MSI) with baseline models on PASCAL-5\\(^i\\). MSI allowed almost all experiments to set a new SOTA record. We observed that VAT + MSI provided the most noticeable gains. In the 1-shot test, VAT + MSI provided a \\(3.0\\%\\) gain with ResNet50 and a \\(2.5\\%\\) gain with ResNet101. COCO-20\\(^i\\) [15]: Tab. 2 reports results on the COCO-20\\(^i\\) dataset. Our method delivered consistent improvement in almost all experiments. VAT + MSI provided a gain of \\(5.5\\%\\) with ResNet50 [7] and \\(7.2\\%\\) with ResNet101 [7] in mIoU in the 1-shot test, and delivered gains of \\(5.8\\%\\) and \\(5.6\\%\\) in the 5-shot test." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19270" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.159, + 0.089, + 0.812, + 0.38 + ], + "angle": 0, + "content": "
BackboneMethods1-shot5-shot
\\( 5^0 \\)\\( 5^1 \\)\\( 5^2 \\)\\( 5^3 \\)mIoUFB-IoU\\( 5^0 \\)\\( 5^1 \\)\\( 5^2 \\)\\( 5^3 \\)mIoUFB-IoU
ResNet50 [7]CWT [19]56.362.059.947.256.4-61.368.568.556.663.7-
RePRI [1]59.868.362.148.559.7-64.671.471.159.366.6-
CyCTR [36]67.872.858.058.064.2-71.173.260.557.565.6-
BAM [12]69.073.667.661.167.8-70.675.170.867.270.9-
DCAMA [29]67.572.359.659.064.676.770.373.267.467.169.580.6
HSNet [21]64.370.760.360.564.076.770.373.267.467.169.580.6
ASNet [11]68.971.761.162.766.177.772.674.365.367.170.880.4
VAT [8]67.671.262.360.165.377.472.473.668.665.770.080.9
HSNet + MSI68.171.558.262.965.276.570.772.861.566.667.978.2
ASNet + MSI69.271.759.764.466.377.972.073.264.068.069.380.2
VAT + MSI71.072.563.865.968.379.173.074.266.670.571.181.2
ResNet101 [7]CWT [19]56.965.261.248.858.0-62.670.268.857.264.7-
RePRI [1]59.668.662.247.259.4-66.271.467.057.765.6-
CyCTR [36]69.372.756.558.664.372.973.574.058.660.266.675.0
DCAMA [29]65.471.463.258.364.677.670.773.766.861.968.380.8
HSNet [21]67.372.362.063.166.277.671.874.467.068.370.480.6
ASNet [11]69.073.162.063.666.978.073.175.665.769.971.181.0
VAT [8]68.472.564.864.267.578.873.375.268.469.571.682.0
HSNet + MSI70.572.960.664.367.177.871.974.964.167.769.779.5
ASNet + MSI70.573.861.365.567.878.873.475.566.271.071.581.3
VAT + MSI73.173.964.768.870.182.373.676.168.071.372.282.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.245, + 0.38, + 0.725, + 0.394 + ], + "angle": 0, + "content": "Table 1. Performance evaluation on Pascal-5 \\( {}^{i} \\) [5]. Best results are shown in bold." + }, + { + "type": "table", + "bbox": [ + 0.129, + 0.406, + 0.616, + 0.626 + ], + "angle": 0, + "content": "
BackboneMethodsI-shot5-shot
200201202203mIoU200201202203mIoU
ResNet50 [7]RePRI [1]32.038.732.733.134.139.345.439.741.841.6
CyCTR [36]38.943.039.639.840.341.148.945.247.045.6
BAM [12]43.450.647.543.446.249.354.251.649.651.2
DCAMA [29]41.945.144.441.743.345.950.550.746.048.3
HSNet [21]36.343.138.738.739.243.351.348.245.046.9
ASNet [11]41.544.142.840.642.247.650.147.746.447.9
VAT [8]39.043.842.639.741.344.151.150.246.147.9
HSNet + MSI40.946.948.845.345.545.353.553.149.350.3
ASNet + MSI41.546.343.542.143.446.050.747.546.947.8
VAT + MSI42.449.249.446.146.847.154.954.151.952.0
ResNet101 [7]DCAMA [29]41.546.245.241.343.548.058.054.347.151.9
HSNet [21]37.244.142.441.341.245.953.051.847.149.5
ASNet [11]41.845.443.241.943.148.052.149.748.249.5
VAT [8]39.544.446.140.442.645.254.151.147.149.4
HSNet + MSI42.450.149.548.347.648.057.352.652.652.6
ASNet + MSI42.945.244.343.444.047.749.949.048.848.9
VAT + MSI44.854.252.348.049.849.358.056.152.754.0
" + }, + { + "type": "table", + "bbox": [ + 0.621, + 0.449, + 0.842, + 0.569 + ], + "angle": 0, + "content": "
BackboneMethodsmIoU
1-shot5-shot
ResNet50 [7]HSNet [21]85.587.8
VAT [8]89.590.3
HSNet + MSI87.588.4
VAT + MSI90.090.6
ResNet101 [7]HSNet [21]86.588.5
VAT [8]90.090.6
HSNet + MSI88.189.2
VAT + MSI90.691.0
" + }, + { + "type": "table_caption", + "bbox": [ + 0.619, + 0.57, + 0.842, + 0.596 + ], + "angle": 0, + "content": "Table 3. Performance evaluation on FSS-1000 [14]." + }, + { + "type": "table_caption", + "bbox": [ + 0.13, + 0.627, + 0.618, + 0.64 + ], + "angle": 0, + "content": "Table 2. Performance evaluation on COCO- \\( {20}^{i} \\) [15]. Best results are shown in bold." + }, + { + "type": "table", + "bbox": [ + 0.17, + 0.662, + 0.376, + 0.773 + ], + "angle": 0, + "content": "
BackboneMethods1-shot mIoU5-shot mIoU
ResNet50 [7]HSNet [21]61.668.7
VAT [8]64.569.7
HSNet + MSI66.070.8
VAT + MSI67.872.6
ResNet101 [7]HSNet [21]64.170.3
VAT [8]66.871.4
HSNet + MSI67.372.3
VAT + MSI69.274.1
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.773, + 0.47, + 0.813 + ], + "angle": 0, + "content": "Table 4. Generalizability performance evaluation on PASCAL-5\\(^i\\) [5] after training with COCO-20\\(^i\\) [15]. Best results are shown in bold." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.84, + 0.471, + 0.903 + ], + "angle": 0, + "content": "FSS-1000 [14]: Tab. 3 compares the performance of our MSI on FSS-1000 using two baselines: HSNet [21] and VAT [8]. HSNet + MSI delivered \\(2.0\\%\\) and \\(0.6\\%\\) mIoU improvements on 1-shot and 5-shot tests, respectively, with" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.664, + 0.892, + 0.725 + ], + "angle": 0, + "content": "ResNet50 [7]. HSNet + MSI with ResNet101 [7] showed \\(1.6\\%\\) and \\(0.7\\%\\) gains in mIoU. VAT + MSI showed gains of \\(0.5\\%\\) and \\(0.3\\%\\) in mIoU with ResNet50 [7] and gains of \\(0.3\\%\\) and \\(0.2\\%\\) in mIoU with ResNet101 [7]." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.73, + 0.894, + 0.837 + ], + "angle": 0, + "content": "Generalization Test: We tested the generalizability of trained models in Tab. 4. HSNet [21] and VAT [8] were compared with HSNet + MSI and VAT + MSI, respectively. Both HSNet + MSI and VAT + MSI delivered significant mIoU gains on 1-shot and 5-shot tests. HSNet + MSI with ResNet50 [7] provided \\(4.4\\%\\) and \\(2.1\\%\\) improvements and VAT + MSI showed \\(3.4\\%\\) and \\(2.7\\%\\) gains." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.84, + 0.894, + 0.903 + ], + "angle": 0, + "content": "Qualitative Results: According to the visual comparison, MSI allows VAT to capture, detailed, accurate, and complete object information, and thus lead to an improved performance and avoid segmenting the wrong object (Fig. 4)." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "19271" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.08, + 0.089, + 0.47, + 0.184 + ], + "angle": 0, + "content": "
Method & BackboneFMSTFSIFmIoUFB-IoU
VAT (ResNet50)✓60.772.0
✓65.3 (Baseline [8])77.4
✓65.277.4
✓✓66.3 (HM [22])78.0
✓✓68.3 (Ours)79.1
✓✓65.777.5
✓✓✓67.178.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.184, + 0.47, + 0.239 + ], + "angle": 0, + "content": "Table 5. Ablation study of the different combination of features with VAT [8] (ResNet50 [7]) on PASCAL-5\\(^i\\) [5]). \\(\\checkmark\\) denotes that these features are utilized to generate super correlation maps (SCM). The best results are shown in bold." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.266, + 0.465, + 0.348 + ], + "angle": 0, + "content": "
BackboneMethods1-shot
200201202203mIoU
ResNet50 [7]VAT [8] (Baseline)67.671.262.360.165.3
VAT+MSI (Feature Add.)68.571.060.862.065.6
VAT+MSI (Correlation Add.)67.068.253.556.061.2
VAT+MSI (Attention)69.972.563.463.867.4
VAT+MSI (Ours)71.072.563.865.968.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.348, + 0.468, + 0.375 + ], + "angle": 0, + "content": "Table 6. Different methods of generating super correlation maps (SCM) on PASCAL- \\(5^{i}\\) [5]. Best results are shown in bold." + }, + { + "type": "table", + "bbox": [ + 0.084, + 0.402, + 0.465, + 0.483 + ], + "angle": 0, + "content": "
BackboneMethods1-shot
200201202203mIoU
ResNet50 (PASCAL-5i)VAT [8]59.942.442.045.547.5
VAT + MSI68.146.643.647.151.4
ResNet50 (COCO-20i)VAT [8]29.732.436.029.031.8
VAT + MSI30.737.940.933.935.9
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.484, + 0.469, + 0.526 + ], + "angle": 0, + "content": "Table 7. Performance comparison on PASCAL- \\(5^{i}\\) [5] and COCO\\(20^{i}\\) [15] for cases where support masks occupy below \\(5\\%\\) of the support images. Best results are shown in bold." + }, + { + "type": "table", + "bbox": [ + 0.084, + 0.554, + 0.465, + 0.622 + ], + "angle": 0, + "content": "
BackboneMethods1-shot
200201202203mIoU
ResNet50 [7]VAT (w/o person in BG)67.770.961.361.665.2
VAT (w/ person in BG)67.671.262.360.165.3
VAT + MSI (w/o person in BG)69.471.460.564.166.3
VAT + MSI (w/ person in BG)71.072.563.865.968.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.622, + 0.468, + 0.65 + ], + "angle": 0, + "content": "Table 8. Training VAT + MSI on PASCAL-5i[5] without the person class existing as background of the support image." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.689, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Small improvement with ASNet/HSNet: Performance drop in 5-shot is observed on PASCAL with HSNet and ASNet. There could be two reasons. First, both HSNet and ASNet models are limited in fully harnessing MSI's potential. Particularly, ASNet downsamples support features by pooling which loses target information and hence limits the capability of both support target features (STF) and support image features (SIF) in MSI. HSNet lacks self-attention, which would aid MSI by facilitating the network in finding target information from the entire SIF by leveraging STF. Second, ASNet, HSNet, VAT, and their MSI-empowered counterparts are trained for the one-shot setting, which might prevent MSI from specializing in 5-shot testing (Tab 1)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.091, + 0.696, + 0.106 + ], + "angle": 0, + "content": "4.2. When is MSI useful?" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.114, + 0.892, + 0.401 + ], + "angle": 0, + "content": "As MSI can better capture target object information, it is more capable of handling challenging FSS scenarios. Fig. 1 draws visual comparisons between \\(\\mathrm{VAT} + \\mathrm{MSI}\\) and the baseline VAT [8] on four challenging FSS cases where MSI is particularly effective. We discuss these cases below. When an instance of the target class is not masked: Fig. 5 visualizes different kinds of features in SIF using \\(\\mathrm{VAT} + \\mathrm{MSI}\\) on PASCAL- \\(5^{i}\\) [5] (ResNet50 [7]). We observe that the support mask fails to mask an instance of the same class, i.e., the sofa on the right side. Therefore, SIF with target features is generated only from the upper sofa. Next, SIF with background features is not very effective overall, even though they better segment the magnified part in the cyan box. Finally, SIF with the entire image's features (ours), which incorporate both the former and the latter features, allows accurate segmentation of the target object, both inside and outside the cyan box. This indicates that background features have target information and utilizing the features improves the performance of FSS." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.402, + 0.893, + 0.553 + ], + "angle": 0, + "content": "Support mask is very small: In PASCAL-5 and COCO-20, there are several cases where the support masks are very small because the target object only occupies a small part of the support image. We compare the mIoU for cases when the support mask occupies less than \\(5\\%\\) of the support image (Tab. 7). Compared to VAT [8], VAT + MSI displays noticeable gains of \\(3.9\\%\\) and \\(4.1\\%\\) (in mIOU) for PASCAL- \\(5^{i}\\) and \\(\\mathrm{COCO - }20^{i}\\), respectively. These results show that MSI is more effective than the existing methods on very small target objects in both PASCAL- \\(5^{i}\\) [5] and COCO- \\(20^{i}\\) [15]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.554, + 0.892, + 0.674 + ], + "angle": 0, + "content": "Support mask is missing some of the target boundary: We observe that in PASCAL- \\(5^{i}\\) [5], COCO- \\(20^{i}\\) [15], and even FSS-1000 [14], the masks around boundaries can be imperfect (Fig. 6). By masking the features with an inaccurate mask, the boundary information of the target disappears inadvertently (Fig. 6). Therefore, compared to ours, previous methods face difficulties in finding the target in the query image with only limited target information." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.675, + 0.893, + 0.901 + ], + "angle": 0, + "content": "When some background is helpful: In some FSS cases, the background offers relevant context that is unavailable in the support mask, for accurate segmentation. However, many recent methods depend on support masks to completely remove the background. We notice the person class frequently exists in the background of the support image in PASCAL- \\(5^{i}\\) [5]. Therefore, in order to empirically validate the importance of leveraging relevant background information, we train VAT+MSI and VAT [8] by removing the segmentation mask of the person class when the person exists in the background of the support image. We compare with or without the person class existing in the background of the support image in Tab. 8 and Fig. 7. After excluding the person class, the performance drop for VAT+MSI was much larger than VAT [8]." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19272" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.134, + 0.089, + 0.84, + 0.337 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.138, + 0.342, + 0.825, + 0.356 + ], + "angle": 0, + "content": "Figure 4. Visual comparison of VAT [8] and \\(\\mathrm{VAT} + \\mathrm{MSI}\\) with ResNet50 [7] on PASCAL- \\(5^{i}\\) [5] and COCO- \\(20^{i}\\) [15]." + }, + { + "type": "image", + "bbox": [ + 0.084, + 0.381, + 0.466, + 0.438 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.441, + 0.47, + 0.496 + ], + "angle": 0, + "content": "Figure 5. Comparison of \\(\\mathrm{VAT} + \\mathrm{MSI}\\) on PASCAL- \\(5^{i}\\) [5] with ResNet50 [7] using different kinds of features in SIF: SIF with only target features, SIF with only background features, and SIF with the entire image's features." + }, + { + "type": "image", + "bbox": [ + 0.083, + 0.511, + 0.466, + 0.585 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.588, + 0.469, + 0.617 + ], + "angle": 0, + "content": "Figure 6. Missing information around boundary on PASCAL- \\(5^{i}\\) [5]. The mask is not perfect to cover entire target object." + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.634, + 0.468, + 0.704 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.707, + 0.469, + 0.777 + ], + "angle": 0, + "content": "Figure 7. Comparison of performance when background information of support set is relevant to the background in the query image. Note that the person is in the background of the support image (target object is the ball). VAT failed to segment the ball correctly, while \\(\\mathrm{VAT} + \\mathrm{MSI}\\) was able to differentiate the ball and people." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.802, + 0.334, + 0.818 + ], + "angle": 0, + "content": "4.3. Ablation Study and Analysis" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Why the masked support image is helpful: (1) Feature masking (FM) is utilized by several existing FSS models [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12], obtained by masking background features. The target features in FM are not merely targeted object features. When extracting target" + }, + { + "type": "image", + "bbox": [ + 0.509, + 0.381, + 0.882, + 0.512 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.516, + 0.892, + 0.598 + ], + "angle": 0, + "content": "Figure 8. Feature map comparison between support target features (STF) and feature masking (FM). The cyan circles show that STF captures more fine-grained features near the target object boundary, however, FM struggles to capture the same. In deeper layers, the advantage of STF becomes more apparent (e.g. Block 3)." + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.602, + 0.889, + 0.679 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.681, + 0.892, + 0.751 + ], + "angle": 0, + "content": "Figure 9. Feature masking (FM) overlooks the impact of the growing receptive field. Background deep features could contain target object information. FM thus loses the detailed target information by masking all features using a support mask. This becomes severe when the support mask is small/inaccurate." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.893, + 0.901 + ], + "angle": 0, + "content": "features in FM, the features corresponding to background objects could also be present because of the enlarging receptive fields [20]. These background features interfere with obtaining target information. However, this interference can be eliminated by masking the background at the input image level in our MSI. (2) STF holds more target features such as the texture and boundary of the target object than FM. In contrast, FM loses such information by masking features to remove the background (Fig. 8) [22]." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19273" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.468 + ], + "angle": 0, + "content": "How MSI helps for each case: FM is utilized in most FSS works to remove the background in support features [34, 33, 31, 23, 35]. (a) When the support mask fails to mask the same target class in a different location, unlike FM, SIF in MSI can still retain the target information (Fig. 5). (b) When the target class is minuscule, FM features retain minimal target information from masking downstream features (Fig. 9). However, in MSI, we mask support images at the input level. As such, we can retain fine-grained information in STF. Also, SIF could hold the target information missed by STF due to a small mask (Tab. 8). (c) FM loses target boundary information (Fig. 6) when removing background features with an inaccurate mask. However, MSI can overcome this by exploiting additional target information in SIF and it facilitates a network in recovering fine-grained target details through the encoder/decoder. (d) FM cannot utilize the contextual features from the background. For example, if the support and query images have the same non-target object in the background, MSI uses \\( CS_{1} \\) to learn contextual features and recognizes the same objects in QF and SIF, and \\( CS_{2} \\) to find the similarity between STF and QF to learn target-specific features to locate the target object (Fig. 3, Eq. 3). Both \\( CS_{1} \\) and \\( CS_{2} \\) allow the network to recognize non-targets (Fig. 7, Tab. 8) and leverage such information." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.472, + 0.47, + 0.593 + ], + "angle": 0, + "content": "Best features for SCM: In Tab. 5, we show results when using various combinations of features to obtain SCM. For this purpose, VAT [8] with ResNet50 backbone is used as a baseline and PASCAL- \\(5^{i}\\) is chosen for training and testing the model. The ablation study reveals that harnessing both SIF and STF via concatenation achieves the best mIoU. Please see the supplementary text for visualizations of the correlation value distributions for SIF and STF." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.596, + 0.473, + 0.793 + ], + "angle": 0, + "content": "On different ways of fusing SIF and STF: The proposed method, MSI, calculates cosine similarity between \\(\\langle\\)STF, QF \\(\\rangle\\) and \\(\\langle\\)SIF, QF \\(\\rangle\\), and concatenates the two generated correlation maps. To see the effectiveness of this method, we experimented with different approaches to fuse SIF and STF to obtain SCM (see Tab. 6). Feature addition refers to the element-wise addition of features before calculating the cosine similarity to get the correlation map. Correlation addition means simply adding two correlation maps elementwise. The attention method merges two correlation maps through 1x1 depth-wise attention based on Attention U-Net [24]. Among all design choices for fusion, concatenating the two correlation maps showed the best performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.796, + 0.472, + 0.904 + ], + "angle": 0, + "content": "Fast training convergence: We notice that MSI with VAT [8] and ResNet50 on PASCAL- \\(5^{i}\\), \\(\\mathrm{VAT} + \\mathrm{MSI}\\), provides 3.3x faster convergence (i.e. to reach mIoU of \\(60\\%\\)) on average than VAT (Fig. 10), along with a remarkable improvement in performance. Similarly with HSNet, HSNet+MSI allows faster convergence by 4.5x on average. See supplementary for plots." + }, + { + "type": "image", + "bbox": [ + 0.514, + 0.092, + 0.885, + 0.208 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.212, + 0.895, + 0.268 + ], + "angle": 0, + "content": "Figure 10. Train. and val. profiles of VAT [8] and \\(\\mathrm{VAT} + \\mathrm{MSI}\\) on PASCAL- \\(5^{i}\\) with ResNet50. \\(\\mathrm{VAT} + \\mathrm{MSI}\\) provides \\(3.3\\mathrm{x}\\) faster convergence (to reach \\(60\\%\\) in mIoU) on average than VAT. Red circles indicate when the training accuracy reaches \\(60\\%\\) in mIoU." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.292, + 0.62, + 0.308 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.317, + 0.895, + 0.455 + ], + "angle": 0, + "content": "We proposed a new method, MSI, maximizing the information of the support set, deviating from the masking method [37] widely used in many FSS models [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12]. The joint exploitation of SIF and STF develops a synergy between them, which allows handling several challenging FSS cases. The results show significant performance improvements across all benchmarks on recent, strong FSS baselines (HSNet [21], ASNet [11], and VAT [8])." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.468, + 0.652, + 0.485 + ], + "angle": 0, + "content": "Acknowledgment" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.493, + 0.892, + 0.523 + ], + "angle": 0, + "content": "This work is supported in part by NSF Grant #1955404 and #1955365." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.538, + 0.597, + 0.553 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.508, + 0.562, + 0.895, + 0.647 + ], + "angle": 0, + "content": "[1] Malik Boudiaf, Hoel Kervadec, Ziko Imtiaz Masud, Pablo Piantanida, Ismail Ben Ayed, and Jose Dolz. Few-Shot Segmentation Without Meta-Learning: A Good Transductive Inference Is All You Need? In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 13979-13988, June 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.648, + 0.895, + 0.731 + ], + "angle": 0, + "content": "[2] Liang-Chieh Chen, George Papandreou, Iasonas Kokkinos, Kevin Murphy, and Alan L. Yuille. DeepLab: Semantic Image Segmentation with Deep Convolutional Nets, Atrous Convolution, and Fully Connected CRFs. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 40(4):834-848, 2018. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.733, + 0.894, + 0.801 + ], + "angle": 0, + "content": "[3] Seokju Cho, Sunghwan Hong, Sangryul Jeon, Yunsung Lee, Kwanghoon Sohn, and Seungryong Kim. CATs: Cost Aggregation Transformers for Visual Correspondence. In Proceedings of Advances in Neural Information Processing Systems (NeurIPS), 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.803, + 0.895, + 0.871 + ], + "angle": 0, + "content": "[4] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. ImageNet: A large-scale hierarchical image database. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 248–255, 2009. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.873, + 0.895, + 0.902 + ], + "angle": 0, + "content": "[5] Mark Everingham, Luc Van Gool, Christopher Williams, John Winn, and Andrew Zisserman. The Pascal Visual Ob-" + }, + { + "type": "list", + "bbox": [ + 0.508, + 0.562, + 0.895, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19274" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.121 + ], + "angle": 0, + "content": "ject Classes (VOC) challenge. International Journal of Computer Vision (IJCV), 88:303-338, 06 2010. 1, 2, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.122, + 0.472, + 0.207 + ], + "angle": 0, + "content": "[6] Xavier Glorot, Antoine Bordes, and Yoshua Bengio. Deep Sparse Rectifier Neural Networks. In Proceedings of the Fourteenth International Conference on Artificial Intelligence and Statistics (AISTAT), volume 15 of Proceedings of Machine Learning Research (PMLR), pages 315-323, Fort Lauderdale, FL, USA, 11-13 Apr 2011. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.208, + 0.472, + 0.275 + ], + "angle": 0, + "content": "[7] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep Residual Learning for Image Recognition. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 770-778, 2016. 3, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.278, + 0.472, + 0.332 + ], + "angle": 0, + "content": "[8] Sunghwan Hong, Seokju Cho, Jisu Nam, and Seungryong Kim. Cost Aggregation Is All You Need for Few-Shot Segmentation. arXiv preprint arXiv:2112.11685, 2021. 2, 3, 5, 6, 7, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.334, + 0.472, + 0.404 + ], + "angle": 0, + "content": "[9] Sunghwan Hong, Seokju Cho, Jisu Nam, Stephen Lin, and Seungryong Kim. Cost Aggregation with 4D Convolutional Swin Transformer for Few-Shot Segmentation. In Proceedings of European Conference on Computer Vision (ECCV), 2022. 1, 2, 3, 4, 5, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.079, + 0.406, + 0.47, + 0.476 + ], + "angle": 0, + "content": "[10] M. Amirul Islam, M. Kowal, S. Jia, K. G. Derpanis, and N. B. Bruce. Global Pooling, More than Meets the Eye: Position Information is Encoded Channel-Wise in CNNs. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 773-781, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.478, + 0.47, + 0.532 + ], + "angle": 0, + "content": "[11] Dahiyun Kang and Minsu Cho. Integrative Few-Shot Learning for Classification and Segmentation. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 1, 2, 3, 4, 5, 6, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.534, + 0.47, + 0.616 + ], + "angle": 0, + "content": "[12] C. Lang, G. Cheng, B. Tu, and J. Han. Learning what not to segment: A new perspective on few-shot segmentation. In 2022 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 8047-8057, Los Alamitos, CA, USA, jun 2022. IEEE Computer Society. 1, 2, 3, 4, 6, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.079, + 0.618, + 0.47, + 0.688 + ], + "angle": 0, + "content": "[13] Gen Li, Varun Jampani, Laura Sevilla-Lara, Deqing Sun, Jonghyun Kim, and Joongkyu Kim. Adaptive Prototype Learning and Allocation for Few-Shot Segmentation. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2021. 1, 2, 3, 4, 5, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.079, + 0.689, + 0.47, + 0.758 + ], + "angle": 0, + "content": "[14] Xiang Li, Tianhan Wei, Yau Pun Chen, Yu-Wing Tai, and Chi-Keung Tang. FSS-1000: A 1000-Class Dataset for Few-Shot Segmentation. Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2020. 2, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.761, + 0.47, + 0.843 + ], + "angle": 0, + "content": "[15] Tsung-Yi Lin, Michael Maire, Serge Belongie, Lubomir Bourdev, Ross Girshick, James Hays, Pietro Perona, Deva Ramanan, C. Lawrence Zitnick, and Piotr Dólar. Microsoft COCO: Common Objects in Context. In Proceedings of European Conference on Computer Vision (ECCV), 2014. 1, 2, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.845, + 0.47, + 0.9 + ], + "angle": 0, + "content": "[16] Weide Liu, Chi Zhang, Henghui Ding, Tzu-Yi Hung, and Guosheng Lin. Few-shot Segmentation with Optimal Transport Matching and Message Flow. IEEE Transactions on Multimedia (TMM), 2022. 1, 2, 4, 5" + }, + { + "type": "list", + "bbox": [ + 0.079, + 0.092, + 0.472, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.162 + ], + "angle": 0, + "content": "[17] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin Transformer: Hierarchical Vision Transformer using Shifted Windows. In Proceedings of International Conference on Computer Vision (ICCV), 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.164, + 0.892, + 0.234 + ], + "angle": 0, + "content": "[18] J. Long, E. Shelhamer, and T. Darrell. Fully convolutional networks for semantic segmentation. In 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3431-3440, Los Alamitos, CA, USA, jun 2015. IEEE Computer Society. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.235, + 0.895, + 0.303 + ], + "angle": 0, + "content": "[19] Zhihe Lu, Sen He, Xiatian Zhu, Li Zhang, Yi-Zhe Song, and Tao Xiang. Simpler is Better: Few-shot Semantic Segmentation with Classifier Weight Transformer. In Proceedings of International Conference on Computer Vision (ICCV), 2021. 1, 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.305, + 0.892, + 0.387 + ], + "angle": 0, + "content": "[20] Wenjie Luo, Yujia Li, Raquel Urtasun, and Richard Zemel. Understanding the effective receptive field in deep convolutional neural networks. In Proceedings of the 30th International Conference on Neural Information Processing Systems, NIPS'16, page 4905-4913, Red Hook, NY, USA, 2016. Curran Associates Inc. 4, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.39, + 0.895, + 0.445 + ], + "angle": 0, + "content": "[21] Juhong Min, Dahiyun Kang, and Minsu Cho. Hypercorrelation Squeeze for Few-Shot Segmentation. In Proceedings of International Conference on Computer Vision (ICCV), pages 6941-6952, 2021. 1, 2, 3, 4, 5, 6, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.447, + 0.892, + 0.516 + ], + "angle": 0, + "content": "[22] Seonghyeon Moon, Samuel S. Sohn, Honglu Zhou, Sejong Yoon, Vladimir Pavlovic, Muhammad Haris Khan, and Mubasir Kapadia. HM: Hybrid Masking for Few-Shot Segmentation. In Proceedings of European Conference on Computer Vision (ECCV), pages 506-523, 2022. 1, 2, 3, 4, 5, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.518, + 0.892, + 0.573 + ], + "angle": 0, + "content": "[23] Khoi Nguyen and Sinisa Todorovic. Feature Weighting and Boosting for Few-Shot Segmentation. In Proceedings of International Conference on Computer Vision (ICCV), 2019, 1, 2, 3, 4, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.575, + 0.892, + 0.658 + ], + "angle": 0, + "content": "[24] Ozan Oktay, Jo Schlemper, Loic Le Folgoc, Matthew C. H. Lee, Mattias P. Heinrich, Kazunari Misawa, Kensaku Mori, Steven G. McDonagh, Nils Y. Hammerla, Bernhard Kainz, Ben Glocker, and Daniel Rueckert. Attention U-Net: Learning Where to Look for the Pancreas. In Medical Imaging with Deep Learning (MIDL), 2018. 5, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.66, + 0.892, + 0.729 + ], + "angle": 0, + "content": "[25] Kate Rakelly, Evan Shelhamer, Trevor Darrell, Alyosha A. Efros, and Sergey Levine. Conditional Networks for Few-Shot Semantic Segmentation. In Workshop Track Proceedings of International Conference on Learning Representations (ICLR), 2018. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.731, + 0.892, + 0.8 + ], + "angle": 0, + "content": "[26] Joseph Redmon, Santosh Divvala, Ross Girshick, and Ali Farhadi. You only look once: Unified, Real-time Object Detection. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 779-788, 2016. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.802, + 0.892, + 0.87 + ], + "angle": 0, + "content": "[27] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster R-CNN: Towards Real-time Object Detection with Region Proposal Networks. Proceedings of Advances in Neural Information Processing Systems (NeurIPS), 28, 2015. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.872, + 0.892, + 0.902 + ], + "angle": 0, + "content": "[28] Amirreza Shaban, Shray Bansal, Zhen Liu, Irfan Essa, and Byron Boots. One-Shot Learning for Semantic Segmenta" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.895, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19275" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.47, + 0.12 + ], + "angle": 0, + "content": "tion. In Proceedings of British Machine Vision Conference (BMVC), pages 167.1-167.13, 2017. 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.472, + 0.217 + ], + "angle": 0, + "content": "[29] Xinyu Shi, Dong Wei, Yu Zhang, Donghuan Lu, Munan Ning, Jiashun Chen, Kai Ma, and Yefeng Zheng. Dense cross-query-and-support attention weighted mask aggregation for few-shot segmentation. In Computer Vision - ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XX, page 151-168, 2022. 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.22, + 0.471, + 0.275 + ], + "angle": 0, + "content": "[30] Mennatullah Siam, Boris N. Oreshkin, and Martin Jägersand. AMP: Adaptive Masked Proxies for Few-Shot Segmentation. In Proceedings of International Conference on Computer Vision (ICCV), pages 5248-5257, 2019. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.277, + 0.471, + 0.344 + ], + "angle": 0, + "content": "[31] Zhuotao Tian, Hengshuang Zhao, Michelle Shu, Zhicheng Yang, Ruiyu Li, and Jiaya Jia. Prior Guided Feature Enrichment Network for Few-Shot Segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 2020. 1, 2, 3, 4, 5, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.347, + 0.471, + 0.415 + ], + "angle": 0, + "content": "[32] Haochen Wang, Xudong Zhang, Yutao Hu, Yandan Yang, Xianbin Cao, and Xiantong Zhen. Few-Shot Semantic Segmentation with Democratic Attention Networks. In Proceedings of European Conference on Computer Vision (ECCV), pages 730-746, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.418, + 0.471, + 0.485 + ], + "angle": 0, + "content": "[33] Kaixin Wang, Jun Hao Liew, Yingtian Zou, Daquan Zhou, and Jiashi Feng. PANet: Few-Shot Image Semantic Segmentation With Prototype Alignment. In Proceedings of International Conference on Computer Vision (ICCV), 2019, 1, 2, 3, 4, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.488, + 0.471, + 0.543 + ], + "angle": 0, + "content": "[34] Boyu Yang, Chang Liu, Bohao Li, Jianbin Jiao, and Ye Qixiang. Prototype Mixture Models for Few-shot Semantic Segmentation. In Proceedings of European Conference on Computer Vision (ECCV), 2020. 1, 2, 3, 4, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.545, + 0.471, + 0.613 + ], + "angle": 0, + "content": "[35] Chi Zhang, Guosheng Lin, Fayao Liu, Rui Yao, and Chunhua Shen. CANet: Class-Agnostic Segmentation Networks With Iterative Refinement and Attentive Few-Shot Learning. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2019. 1, 2, 3, 4, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.615, + 0.471, + 0.668 + ], + "angle": 0, + "content": "[36] Gengwei Zhang, Guoliang Kang, Yi Yang, and Yunchao Wei. Few-Shot Segmentation via Cycle-Consistent Transformer. arXiv preprint arXiv:2106.02320, 2021. 2, 3, 4, 6, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.672, + 0.471, + 0.726 + ], + "angle": 0, + "content": "[37] Xiaolin Zhang, Yunchao Wei, Yi Yang, and Thomas Huang. SG-One: Similarity Guidance Network for One-Shot Semantic Segmentation. IEEE Transactions on Cybernetics, 50:3855-3865, 2020. 1, 2, 3, 4, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.728, + 0.471, + 0.783 + ], + "angle": 0, + "content": "[38] Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, and Jiaya Jia. Pyramid Scene Parsing Network. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 6230-6239, 2017. 1" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.472, + 0.783 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19276" + } + ] +] \ No newline at end of file diff --git a/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/18b3712a-f7d6-4a6b-8811-754fd084ad1d_origin.pdf b/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/18b3712a-f7d6-4a6b-8811-754fd084ad1d_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..9720354b8ea308fa44aa23b347cd7c7f97e101a7 --- /dev/null +++ b/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/18b3712a-f7d6-4a6b-8811-754fd084ad1d_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:3aeb9d5aa5905891298ede0973233b403f3c259e26eeb43020c9de9b23ed4422 +size 8249895 diff --git a/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/full.md b/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/full.md new file mode 100644 index 0000000000000000000000000000000000000000..a91dfde1b8058349d36fe1dcf329e6e63b975f44 --- /dev/null +++ b/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/full.md @@ -0,0 +1,308 @@ +# MSI: Maximize Support-Set Information for Few-Shot Segmentation + +Seonghyeon Moon +Rutgers University + +sm2062@rutgers.edu + +Samuel S. Sohn +Rutgers University + +samuel.sohn@rutgers.edu + +Honglu Zhou +NEC Laboratories America + +hozhou@nec-labs.com + +Sejong Yoon + +The College of New Jersey + +yoons@tcnj.edu + +Vladimir Pavlovic +Rutgers University + +vladimir@rutgers.edu + +Muhammad Haris Khan +Mohamed Bin Zayed University of Artificial Intelligence + +muhammad.haris@mbzuai.ac.ae + +Mubbasir Kapadia +Rutgers University + +mubbasir.kapadia@rutgers.edu + +# Abstract + +FSS (Few-shot segmentation) aims to segment a target class using a small number of labeled images (support set). To extract information relevant to the target class, a dominant approach in best performing FSS methods removes background features using a support mask. We observe that this feature excision through a limiting support mask introduces an information bottleneck in several challenging FSS cases, e.g., for small targets and/or inaccurate target boundaries. To this end, we present a novel method (MSI), which maximizes the support-set information by exploiting two complementary sources of features to generate super correlation maps. We validate the effectiveness of our approach by instantiating it into three recent and strong FSS methods. Experimental results on several publicly available FSS benchmarks show that our proposed method consistently improves performance by visible margins and leads to faster convergence. Our code and trained models are available at: https://github.com/moonsh/MSI-Maximize-Support-Set-Information + +# 1. Introduction + +Deep convolutional neural networks (DCNNs) have achieved state-of-the-art results across several mainstream computer vision (CV) problems, including object detection [26, 27] and semantic segmentation [18, 2, 38]. An important factor underlying the success of DCNNs is large-scale annotated datasets, which are costly and cumbersome to acquire in many dense prediction tasks, such as semantic segmentation. Moreover, these models struggle to segment novel objects when only a few annotated examples are + +(a) + +![](images/c29d178004acd6070f5e01dc9699b87f415ed6e6d2f369282e92888ffcdc82a9.jpg) +Figure 1. Recent FSS baseline (VAT[9]) struggles to accurately segment the target object in several challenging scenarios in PASCAL [5] and $\mathrm{COCO}^i$ [15]: (a) the same instance of the target class is not masked, e.g., the sofa on the right, (b) the support mask is very small compared to the entire image, e.g., flowers in the pot, (c) support mask is missing some target boundary information, e.g., the front and chimney of the train, and (d) the background contains some important contextual information, unavailable in the support mask, e.g., shoes and grass. Our method (MSI) is capable of accurately segmenting target objects. It maximizes the support set information to compensate for the limited support mask information and can exploit relevant contextual information from the background. + +available. Many existing few-shot segmentation (FSS) approaches [25, 30, 34, 23, 31, 33, 35, 13, 32, 16, 37, 19, 21, 11, 12, 9, 22] aim to address this shortcoming. The problem settings in FSS require accurate segmentation of a target ob + +![](images/f0d470f213d76468e071e8e9bc82cb6c1945c1b775be733ee3345b61edffdbbf.jpg) + +![](images/6fd00709779a12f4c7e062650f4900735b403bd52b695f959c2ea943a88b5072.jpg) + +![](images/ea065c0dcf99bb48f1ac21ed1012e5f370231929e8b3bc75fc28334d78109dc4.jpg) +Figure 2. (a) Many FSS methods use support mask to remove background features [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12], denoted as feature masking (FM), and so rely only on target object features. (b) Recent work, HM [22], merges both image masking and feature masking to achieve hybrid masking for improving target information. (c) We propose to maximize the support set information (MSI) to compensate for the limited support mask information and exploit relevant contextual information from the background. + +ject in a query image, given few annotated images, termed the support set, from the target class. + +Shaban et al.'s work [28] introduced the first FSS model, in which a masked support image was used to extract only the target features. Using the target features, both segmentation and conditioning branches are trained to segment an object of the target class. Later, Zhang et al. [37] show that extracting target features using masked average pooling (MAP) is more beneficial for network learning than obtaining features by masking images. Since then, many FSS models [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12] have considered MAP as the de facto technique for obtaining target features and focus on improving the encoder/decoder network. Recently, HSNet [21] proposed to utilize more effective target features extracted from multiple layers of a deep backbone network. Likewise, ASNet [11] and VAT [9] proposed different network architectures to harness deep features. + +Despite promising results, many recent methods, including HSNet [21], ASNet [11], and VAT [9], systematically struggle with few challenging FSS cases (Fig. 1): (a) When the support mask does not mask all instances of the same target class; (b) The support mask is unable to faithfully capture object boundaries; (c) The support mask is too + +small, carrying limited object information; and (d) The background contains some important contextual information, unavailable in the support mask, for accurately segmenting the target object. We conjecture that this happens because many current SOTA methods rely on support masks to completely remove the background (Fig. 2), which limits the useful information in several challenging FSS cases. + +In this paper, we propose a new method to overcome the limited information bottleneck from the support mask. It is based on the intuition that upon maximizing the information from the masked support set images (MSI), it is possible to compensate for the limited support mask information by utilizing the important contextual information available in the typically discarded background (Fig. 2). MSI jointly exploits two complementary sources of features. The first set of features is obtained by using masked support images, which only activate the target-related features in the query image. The second set of features is generated from the full support images, which activate the features of all similar objects shared between the support and query images. The former features act as an anchor for the latter in localizing a certain target class while supplementing it with the target boundary information. We summarize our key contributions as follows: + +- We propose MSI, an efficient and effective plug-and-play module for FSS methods. MSI harnesses masked support images to capture the delineated target information and exploits the entire support image for complete target information. +- We perform extensive experiments and analysis on three challenging FSS benchmarks: PASCAL- $5^{i}$ [5], COCO- $20^{i}$ [15], and FSS-1000 [14]. Results show that MSI consistently improves mIoU in the one-shot setting over all strong baselines, including HSNet [21], ASNet [11], and VAT [9]. +- MSI improves the training speed of recent baseline models on PASCAL-5 $^i$ [5], with 3.3x average speed-up on VAT [8] and 4.5x on HSNet [21]. + +# 2. Related Works + +Few-shot segmentation: OSLSM [28] is considered to be the first work introducing FSS problem. OSLSM proposed a model consisting of a condition branch and a segmentation branch. Since OSLSM, various methods have been proposed to solve the FSS problem [25, 30, 34, 23, 31, 33, 35, 13, 32, 16, 37, 19, 21, 11, 12, 9, 22]. + +MAP (Masked Average Pooling): Zhang et al. [37] proposed the MAP to collect target information from the support set. MAP masks features instead of masking support images and uses average pooling to extract target information. They argued that (1) removing the background from support images increases the variance of the input data for a unified network and (2) masking the im + +age will make the network biased toward the target image. For these reasons, MAP was recommended to get target features. Since Zhang et al. [37], many few shot works [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12] are following MAP to extract target features. However, by performing average pooling, spatial information is inevitably lost [10]. In this work, we utilized the masked support image to generate target features without using MAP. Therefore, we can retrieve fine-detail texture information and preserve spatial information. + +Multi-layer features: Instead of using MAP, HSNet [21] proposed to use deep features extracted from multiple layers and designed an effective convolution to process the features. To process the deep features effectively and efficiently, VAT [8] proposed a model based on the swim transformer [17] and ASNet [11] proposed the attentive squeeze network. HM [22] proposed hybrid masking to compensate for the lost details in feature masking. Although the spatial information that MAP lost was preserved, these works extracted target features counting on support masks. Therefore, when the support masks give limited information, limited target information is extracted. In this paper, not only is information loss minimized when the target features are extracted by relying on the support mask, but also more meaningful target features are extracted by utilizing both the entire support image and the masked support image. + +Utilizing background information: There have been several attempts to improve FSS accuracy by using background information [34, 12]. PMM [34] proposed a method of deactivating the background and activating the target object using a duplex manner. Negative learning was carried out with objects in the background, and on the other hand, positive learning was conducted using the foreground object. Afterward, the two learning results were used to segment the target object accurately. Similarly, BAM [12] also proposed to use two learners. The base learner was trained using objects in the background and a meta learner was trained with the foreground object. These two learners were integrated to predict segmentation accurately. However, they assumed that the background lacks meaningful target information. Therefore, they missed target information that might exist in the background. We obtain even more target information from the background and simultaneously utilize background information to avoid segmenting wrong objects. + +Cross attention: Both CyCTR [36] and DCAMA [29] utilize the transformer architecture to achieve cross-attention between the support and query features. This cross-attention allows the identification of target information beyond the mask area. Despite this, both methods rely on an unmasked support image to extract target information, leading to the loss of delineated detailed target information. On the contrary, MSI proposes to directly provide the model + +with features from the masked support image and the full support image, thereby introducing a strong inductive bias that ultimately leads to better performance. MSI computes the cosine similarity between these two complementary sets of features and concatenates them. Therefore, MSI can retain detailed target information. It is more intuitive and simpler and can be plugged seamlessly into various FSS baselines, as validated in our experiments. + +# 3. Overall Method + +Fig. 3 displays the overall architecture of our method. Following recent works [21, 11, 9], it consists of a backbone network (ResNet-50 [7] or ResNet-101 [7]) pre-trained on ImageNet [4] to obtain multi-layer features, and an encoder/decoder network to predict the segmentation mask. We propose a new plug-and-play module to maximize the support set information (MSI), which compensates for limited support mask information by exploiting relevant contextual information from the background. MSI extracts support target features (STF), containing delineated target class information from the support images, and support image features (SIF), accounting for the information in the entire support image. Next, STF and SIF are leveraged to obtain their respective correlation maps by computing the cosine similarity with respect to the query features (QF) obtained from the query image. Then, the correlation maps corresponding to STF and SIF are utilized to get super correlation maps (SCM). Finally, this SCM is used as the input to the encoder and decoder which can be from recent FSS methods (e.g., [21], [9], and [11]). + +# 3.1. Preliminaries + +The goal of few-shot segmentation is to train a model that can segment the target object in a query image when provided with a few annotated example images from the target class. Following prior work in FSS [21, 11, 9], we utilize the episodic scheme for training our model. + +Specifically, we assume the availability of two disjoint sets, $C_{train}$ and $C_{test}$ as training and testing classes, respectively. The training data $D_{train}$ is sampled from $C_{train}$ and the testing data $D_{test}$ is from $C_{test}$ . We then construct multiple episodes from $D_{train}$ and $D_{test}$ . An episode is comprised of a support set, $S = (I^s, M^s)$ , and a query set, $Q = (I^q, M^q)$ , where $I^*$ and $M^*$ denote an image and its corresponding mask. Furthermore, $D_{train} = \{(S_i, Q_i)\}_{i=1}^{N_{train}}$ and $D_{test} = \{(S_i, Q_i)\}_{i=1}^{N_{test}}$ , where $N_{train}$ represents the number of episodes for training and $N_{test}$ is the number of episodes for testing. During training, we iteratively sample episodes from $D_{train}$ to train a model that learns a mapping from $(I^s, M^s, I^q)$ to query mask $M^q$ . The learned model is used without further optimization by randomly sampling episodes from the testing data $D_{test}$ in the same manner and comparing the predicted query masks to the ground truth. + +![](images/517280b1a0d18b5736c3ca7e96103b434df1c87440015071ad4acef8ff5e6350.jpg) +Figure 3. Overall architecture. To maximize the usability of the support set, first we extract support image features (SIF) and support target features (STF) through the backbone. SIF branch creates features using the entire support image, and STF branch extracts the features after removing background pixels. The query features (QF) are obtained from the query. We obtain correlation maps by calculating the cosine similarity (CS) of the STF and SIF with the QF, respectively, and these correlation maps are concatenated to make super correlation maps (SCM). $CS_2$ represents the cosine similarity between the target object and the query image. Therefore, only target-related information in the query image will be activated. $CS_1$ , on the other hand, assesses the cosine similarity between the entire support image and the query image. Consequently, all the similar objects between the support image and the query image are activated. + +![](images/778e68e85738e753d0cbc0cd70b6ccfae1ae97589b11cf873941735e943c6888.jpg) + +# 3.2. Maximizing Support-Set Information: MSI + +An important question for the FSS pipeline is where in a network it is most suitable to use masking to provide target information to the network. Earlier attempts, such as the work of Shaban et al. [28] suggested masking the background in the input image so that only target features are obtained. The rationale was that the network would supposedly be biased toward large objects, so removing the background would decrease the variance of the output parameters. Later, Zhang et al. [37] proposed to mask the background after extracting features because masking the input image makes a network biased towards the target image and changes the statistical distribution of the support image set. Many recent state-of-the-art methods have conformed to this approach [34, 33, 31, 23, 35, 16, 13, 36, 21, 9, 11, 12]. + +Motivation: Although these methods report promising performance, we note that many recent methods, including HSNet [21], ASNet [11], and VAT [9], struggle to accurately predict the segmentation mask in several challenging scenarios (Fig. 1). We believe that this occurs because many recent FSS methods fully rely on the support mask to remove the background features (Fig. 2). These support masks likely present an information bottleneck in such challenging cases. For instance, when they are very small, they fail to properly encapsulate target object boundaries or do not capture all instances of the target object. + +We put forth a new approach (MSI) to alleviate the aforementioned limitations of support masks. We believe that by maximizing the information from support images, it becomes possible to compensate for the limited information in the support mask and also leverage important contextual information available in the background. Specifically, we + +extract support target features (STF), which contain delineated target class information in the support image, and support image features (SIF), which contain contextualized information from the entire support image. This is because the STF enables the acquisition of more focused and fine-grained target information, and compared to feature masking (Fig. 2) STF captures more accurate object boundaries because the receptive field can cover even the area beyond target object at deep features [20, 22]. On the other hand, SIF utilizes the full support image to capture relevant and useful target information that exists in the background. This allows us to obtain both detailed and complete information about the target class to avoid segmenting wrong objects. We leverage STF and SIF to obtain their respective correlation maps by computing their cosine similarity with the query features (QF), which are obtained from the query image. The correlation maps corresponding to STF and SIF are then combined into Super Correlation Maps (SCM), which are inputted to the encoder and decoder. + +Formalizing STF and SIF: Support image features (SIF), $\alpha_{i=1}^{N}$ , where $N$ is the number of features, refer to the features of the entire support image, $I^{S} \in \mathbb{R}^{3 \times w \times h}$ , where $w$ is the width and $h$ is the height of the image. Support target features (STF), $\beta_{i=1}^{N}$ , are the features from the target image, $I^{T} \in \mathbb{R}^{3 \times w \times h}$ , which is a masked support image using support mask $\mathbf{M}^{S} \in \{0,1\}^{w \times h}$ . Formally, + +$$ +I ^ {T} = I ^ {S} \odot \zeta (M ^ {S}), \tag {1} +$$ + +where $\zeta (\cdot)$ resizes the mask $M^S$ to fit the dimension of the image $I^{S}$ and $\odot$ denotes the Hadamard product. Query features (QF), $\kappa_{i = 1}^{N}$ , are obtained from the query image, $I^Q\in \mathbb{R}^{3\times w\times h}$ + +For each image $(I^S, I^T, \text{and} I^Q)$ , the backbone network, $\triangleleft$ , produces $N$ number of features $(\alpha_{i=1}^N, \beta_{i=1}^N, \text{and} \kappa_{i=1}^N$ respectively) from its intermediate layers. + +$$ +\alpha_ {i = 1} ^ {N} = \triangleleft (I ^ {S}), \beta_ {i = 1} ^ {N} = \triangleleft (I ^ {T}), \kappa_ {i = 1} ^ {N} = \triangleleft (I ^ {Q}), (2) +$$ + +where features, $\alpha_{i},\beta_{i},\kappa_{i}\in \mathbb{R}^{c_{i}\times w_{i}\times h_{i}}$ , have different sizes of channel and spatial dimensions. Features extracted from deeper layers have a large number of channels with smaller width and height dimensions. + +Super Correlation Maps (SCM): We calculate the cosine similarities of $\alpha_{i=1}^{N}$ and $\beta_{i=1}^{N}$ with respect to $\kappa_{i=1}^{N}$ using the Eq. 3 to get correlation maps $C_i \in \mathbb{R}^{1 \times w_i \times h_i \times w_i \times h_i}$ and $S_i \in \mathbb{R}^{1 \times w_i \times h_i \times w_i \times h_i}$ . To perform multiplication between features, we reshape and transpose the features, $\alpha_{i=1}^{N}, \beta_{i=1}^{N}$ , and $\kappa_{i=1}^{N}$ into $\alpha_{i=1}^{\prime N} \in \mathbb{R}^{(w_i \cdot h_i) \times c_i}$ , $\beta_{i=1}^{\prime N} \in \mathbb{R}^{(w_i \cdot h_i) \times c_i}$ , and $\kappa_{i=1}^{\prime N} \in \mathbb{R}^{c_i \times (w_i \cdot h_i)}$ . + +$$ +C S _ {1} = C _ {i = 1} ^ {N} = \operatorname {R e L U} \left(\frac {\alpha_ {i = 1} ^ {\prime N} \cdot \kappa_ {i = 1} ^ {\prime N}}{\| \alpha_ {i = 1} ^ {\prime N} \| \| \kappa_ {i = 1} ^ {\prime N} \|}\right), \tag {3} +$$ + +$$ +C S _ {2} = S _ {i = 1} ^ {N} = \mathrm {R e L U} \bigg (\frac {\beta_ {i = 1} ^ {\prime N} \cdot \kappa_ {i = 1} ^ {\prime N}}{\| \beta_ {i = 1} ^ {\prime N} \| \| \kappa_ {i = 1} ^ {\prime N} \|} \bigg), +$$ + +where $N$ the is number of features and ReLU [6] removes inactivated and noisy values in the correlation map $C_i$ and $S_{i}$ . Correlation maps $C_{i = 1}^{N}$ and $S_{i = 1}^{N}$ are concatenated along the first dimension to obtain the Super Correlation Maps (SCM), $P_{i = 1}^{N}\in \mathbb{R}^{2\times w_{i}\times h_{i}\times w_{i}\times h_{i}}$ (Eq. 4). + +$$ +S C M = P _ {i = 1} ^ {N} = \left[ C _ {i = 1} ^ {N} \oplus S _ {i = 1} ^ {N} \right], \tag {4} +$$ + +where $\oplus$ denotes the concatenation. + +# 3.3. Encoder and Decoder Architecture + +SCM can be fed as input to any encoder and decoder architecture of FSS methods. In order to validate our proposed method, we experiment with feeding SCM as input to three recent and strong encoder-decoder based FSS methods: HSNet [21], ASNet [11], and VAT [8]. For HSNet and VAT, the input channel size of the encoder in the models was doubled. For ASNet, SCM is merged using depth-wise attention based on Attention U-Net [24] instead of changing the input channel size. Otherwise, the architectures of the models were unchanged. + +# 4. Experiments + +Datasets: We use three widely used and publicly available datasets for evaluating our method (MSI): PASCAL- $5^{i}$ [5], COCO- $20^{i}$ [15] and FSS-1000 [14]. PASCAL- $5^{i}$ consists of 20 classes, whereas COCO- $20^{i}$ has 100 classes and FSS-1000 contains 1000 classes. Following previous works [21, 11, 9], we cross validate using 4 folds for PASCAL- $5^{i}$ and COCO- $20^{i}$ and we divide the classes into 4 + +groups for training and testing. Therefore, 5 and 20 classes are used for each fold testing on PASCAL- $5^{i}$ and COCO $20^{i}$ , respectively. Other remaining classes are used for training. For FSS-1000, 1000 classes are divided into 520, 240 and 240 for the training, validation and testing. Lastly, in order to evaluate the generalizability of our method, COCO $20^{i}$ is used for training, and PASCAL- $5^{i}$ for testing. To avoid class overlapping between training and testing, following previous works [21, 31], we change the PASCAL- $5^{i}$ class order for each fold. + +Implementation details: We incorporate MSI into three baseline models, HSNet [21], VAT [8], and ASNet [11], and refer to them as HSNet + MSI, ASNet + MS and VAT + MSI. The backbone networks, ResNet50 [7] and ResNet101 [7], are pre-trained on ImageNet [4], and are used to extract deep features following HSNet, ASNet, and VAT (features from conv3_x to conv5_x before the ReLU [6] activation of each layer stacked to form the deep features). No fine-tuning of backbones was performed. For a fair comparison with the existing models, we keep their default hyperparameters, as listed in their codebases. For VAT training, CATs data augmentation [3] was used and the batch size was reduced due to GPU memory limitations. Specifically, the batch sizes 4, 8, and 4 were used for PASCAL $^{5^i}$ [5], COCO-20 $^{i}$ [15], and FSS-1000 [14] respectively. No data augmentation was employed for training HSNet + MSI and ASNet + MSI. + +Super-correlation maps for K-Shots>1: Given a query image and K support-set images, we compute SCM for each query-support pair, resulting in K SCMs and K corresponding mask predictions from the model. All predictions are summed and normalized by the highest score [21, 11, 9]. + +Evaluation metrics: We report FSS performance using mean Intersection-over-Union (mIoU) and Foreground and Background IoU (FB-IoU), which are widely used by existing methods [16, 31, 13, 21, 11, 9, 22]. We calculate mIoU = $\frac{1}{n}\sum_{1}^{n}IoU$ where $n$ is the number of test cases and FB-IoU = $\frac{1}{2}(IoU_F + IoU_B)$ where $F$ is foreground and $B$ is background without considering classes. + +# 4.1. Results + +PASCAL-5 $^i$ [5]: Tab. 1 compares the results of the proposed method (MSI) with baseline models on PASCAL-5 $^i$ . MSI allowed almost all experiments to set a new SOTA record. We observed that VAT + MSI provided the most noticeable gains. In the 1-shot test, VAT + MSI provided a $3.0\%$ gain with ResNet50 and a $2.5\%$ gain with ResNet101. COCO-20 $^i$ [15]: Tab. 2 reports results on the COCO-20 $^i$ dataset. Our method delivered consistent improvement in almost all experiments. VAT + MSI provided a gain of $5.5\%$ with ResNet50 [7] and $7.2\%$ with ResNet101 [7] in mIoU in the 1-shot test, and delivered gains of $5.8\%$ and $5.6\%$ in the 5-shot test. + +
BackboneMethods1-shot5-shot
\( 5^0 \)\( 5^1 \)\( 5^2 \)\( 5^3 \)mIoUFB-IoU\( 5^0 \)\( 5^1 \)\( 5^2 \)\( 5^3 \)mIoUFB-IoU
ResNet50 [7]CWT [19]56.362.059.947.256.4-61.368.568.556.663.7-
RePRI [1]59.868.362.148.559.7-64.671.471.159.366.6-
CyCTR [36]67.872.858.058.064.2-71.173.260.557.565.6-
BAM [12]69.073.667.661.167.8-70.675.170.867.270.9-
DCAMA [29]67.572.359.659.064.676.770.373.267.467.169.580.6
HSNet [21]64.370.760.360.564.076.770.373.267.467.169.580.6
ASNet [11]68.971.761.162.766.177.772.674.365.367.170.880.4
VAT [8]67.671.262.360.165.377.472.473.668.665.770.080.9
HSNet + MSI68.171.558.262.965.276.570.772.861.566.667.978.2
ASNet + MSI69.271.759.764.466.377.972.073.264.068.069.380.2
VAT + MSI71.072.563.865.968.379.173.074.266.670.571.181.2
ResNet101 [7]CWT [19]56.965.261.248.858.0-62.670.268.857.264.7-
RePRI [1]59.668.662.247.259.4-66.271.467.057.765.6-
CyCTR [36]69.372.756.558.664.372.973.574.058.660.266.675.0
DCAMA [29]65.471.463.258.364.677.670.773.766.861.968.380.8
HSNet [21]67.372.362.063.166.277.671.874.467.068.370.480.6
ASNet [11]69.073.162.063.666.978.073.175.665.769.971.181.0
VAT [8]68.472.564.864.267.578.873.375.268.469.571.682.0
HSNet + MSI70.572.960.664.367.177.871.974.964.167.769.779.5
ASNet + MSI70.573.861.365.567.878.873.475.566.271.071.581.3
VAT + MSI73.173.964.768.870.182.373.676.168.071.372.282.3
+ +Table 1. Performance evaluation on Pascal-5 ${}^{i}$ [5]. Best results are shown in bold. + +
BackboneMethodsI-shot5-shot
200201202203mIoU200201202203mIoU
ResNet50 [7]RePRI [1]32.038.732.733.134.139.345.439.741.841.6
CyCTR [36]38.943.039.639.840.341.148.945.247.045.6
BAM [12]43.450.647.543.446.249.354.251.649.651.2
DCAMA [29]41.945.144.441.743.345.950.550.746.048.3
HSNet [21]36.343.138.738.739.243.351.348.245.046.9
ASNet [11]41.544.142.840.642.247.650.147.746.447.9
VAT [8]39.043.842.639.741.344.151.150.246.147.9
HSNet + MSI40.946.948.845.345.545.353.553.149.350.3
ASNet + MSI41.546.343.542.143.446.050.747.546.947.8
VAT + MSI42.449.249.446.146.847.154.954.151.952.0
ResNet101 [7]DCAMA [29]41.546.245.241.343.548.058.054.347.151.9
HSNet [21]37.244.142.441.341.245.953.051.847.149.5
ASNet [11]41.845.443.241.943.148.052.149.748.249.5
VAT [8]39.544.446.140.442.645.254.151.147.149.4
HSNet + MSI42.450.149.548.347.648.057.352.652.652.6
ASNet + MSI42.945.244.343.444.047.749.949.048.848.9
VAT + MSI44.854.252.348.049.849.358.056.152.754.0
+ +
BackboneMethodsmIoU
1-shot5-shot
ResNet50 [7]HSNet [21]85.587.8
VAT [8]89.590.3
HSNet + MSI87.588.4
VAT + MSI90.090.6
ResNet101 [7]HSNet [21]86.588.5
VAT [8]90.090.6
HSNet + MSI88.189.2
VAT + MSI90.691.0
+ +Table 3. Performance evaluation on FSS-1000 [14]. +Table 2. Performance evaluation on COCO- ${20}^{i}$ [15]. Best results are shown in bold. + +
BackboneMethods1-shot mIoU5-shot mIoU
ResNet50 [7]HSNet [21]61.668.7
VAT [8]64.569.7
HSNet + MSI66.070.8
VAT + MSI67.872.6
ResNet101 [7]HSNet [21]64.170.3
VAT [8]66.871.4
HSNet + MSI67.372.3
VAT + MSI69.274.1
+ +Table 4. Generalizability performance evaluation on PASCAL-5 $^i$ [5] after training with COCO-20 $^i$ [15]. Best results are shown in bold. + +FSS-1000 [14]: Tab. 3 compares the performance of our MSI on FSS-1000 using two baselines: HSNet [21] and VAT [8]. HSNet + MSI delivered $2.0\%$ and $0.6\%$ mIoU improvements on 1-shot and 5-shot tests, respectively, with + +ResNet50 [7]. HSNet + MSI with ResNet101 [7] showed $1.6\%$ and $0.7\%$ gains in mIoU. VAT + MSI showed gains of $0.5\%$ and $0.3\%$ in mIoU with ResNet50 [7] and gains of $0.3\%$ and $0.2\%$ in mIoU with ResNet101 [7]. + +Generalization Test: We tested the generalizability of trained models in Tab. 4. HSNet [21] and VAT [8] were compared with HSNet + MSI and VAT + MSI, respectively. Both HSNet + MSI and VAT + MSI delivered significant mIoU gains on 1-shot and 5-shot tests. HSNet + MSI with ResNet50 [7] provided $4.4\%$ and $2.1\%$ improvements and VAT + MSI showed $3.4\%$ and $2.7\%$ gains. + +Qualitative Results: According to the visual comparison, MSI allows VAT to capture, detailed, accurate, and complete object information, and thus lead to an improved performance and avoid segmenting the wrong object (Fig. 4). + +
Method & BackboneFMSTFSIFmIoUFB-IoU
VAT (ResNet50)✓60.772.0
✓65.3 (Baseline [8])77.4
✓65.277.4
✓✓66.3 (HM [22])78.0
✓✓68.3 (Ours)79.1
✓✓65.777.5
✓✓✓67.178.8
+ +Table 5. Ablation study of the different combination of features with VAT [8] (ResNet50 [7]) on PASCAL-5 $^i$ [5]). $\checkmark$ denotes that these features are utilized to generate super correlation maps (SCM). The best results are shown in bold. + +
BackboneMethods1-shot
200201202203mIoU
ResNet50 [7]VAT [8] (Baseline)67.671.262.360.165.3
VAT+MSI (Feature Add.)68.571.060.862.065.6
VAT+MSI (Correlation Add.)67.068.253.556.061.2
VAT+MSI (Attention)69.972.563.463.867.4
VAT+MSI (Ours)71.072.563.865.968.3
+ +Table 6. Different methods of generating super correlation maps (SCM) on PASCAL- $5^{i}$ [5]. Best results are shown in bold. + +
BackboneMethods1-shot
200201202203mIoU
ResNet50 (PASCAL-5i)VAT [8]59.942.442.045.547.5
VAT + MSI68.146.643.647.151.4
ResNet50 (COCO-20i)VAT [8]29.732.436.029.031.8
VAT + MSI30.737.940.933.935.9
+ +Table 7. Performance comparison on PASCAL- $5^{i}$ [5] and COCO $20^{i}$ [15] for cases where support masks occupy below $5\%$ of the support images. Best results are shown in bold. + +
BackboneMethods1-shot
200201202203mIoU
ResNet50 [7]VAT (w/o person in BG)67.770.961.361.665.2
VAT (w/ person in BG)67.671.262.360.165.3
VAT + MSI (w/o person in BG)69.471.460.564.166.3
VAT + MSI (w/ person in BG)71.072.563.865.968.3
+ +Table 8. Training VAT + MSI on PASCAL-5i[5] without the person class existing as background of the support image. + +Small improvement with ASNet/HSNet: Performance drop in 5-shot is observed on PASCAL with HSNet and ASNet. There could be two reasons. First, both HSNet and ASNet models are limited in fully harnessing MSI's potential. Particularly, ASNet downsamples support features by pooling which loses target information and hence limits the capability of both support target features (STF) and support image features (SIF) in MSI. HSNet lacks self-attention, which would aid MSI by facilitating the network in finding target information from the entire SIF by leveraging STF. Second, ASNet, HSNet, VAT, and their MSI-empowered counterparts are trained for the one-shot setting, which might prevent MSI from specializing in 5-shot testing (Tab 1). + +# 4.2. When is MSI useful? + +As MSI can better capture target object information, it is more capable of handling challenging FSS scenarios. Fig. 1 draws visual comparisons between $\mathrm{VAT} + \mathrm{MSI}$ and the baseline VAT [8] on four challenging FSS cases where MSI is particularly effective. We discuss these cases below. When an instance of the target class is not masked: Fig. 5 visualizes different kinds of features in SIF using $\mathrm{VAT} + \mathrm{MSI}$ on PASCAL- $5^{i}$ [5] (ResNet50 [7]). We observe that the support mask fails to mask an instance of the same class, i.e., the sofa on the right side. Therefore, SIF with target features is generated only from the upper sofa. Next, SIF with background features is not very effective overall, even though they better segment the magnified part in the cyan box. Finally, SIF with the entire image's features (ours), which incorporate both the former and the latter features, allows accurate segmentation of the target object, both inside and outside the cyan box. This indicates that background features have target information and utilizing the features improves the performance of FSS. + +Support mask is very small: In PASCAL-5 and COCO-20, there are several cases where the support masks are very small because the target object only occupies a small part of the support image. We compare the mIoU for cases when the support mask occupies less than $5\%$ of the support image (Tab. 7). Compared to VAT [8], VAT + MSI displays noticeable gains of $3.9\%$ and $4.1\%$ (in mIOU) for PASCAL- $5^{i}$ and $\mathrm{COCO - }20^{i}$ , respectively. These results show that MSI is more effective than the existing methods on very small target objects in both PASCAL- $5^{i}$ [5] and COCO- $20^{i}$ [15]. + +Support mask is missing some of the target boundary: We observe that in PASCAL- $5^{i}$ [5], COCO- $20^{i}$ [15], and even FSS-1000 [14], the masks around boundaries can be imperfect (Fig. 6). By masking the features with an inaccurate mask, the boundary information of the target disappears inadvertently (Fig. 6). Therefore, compared to ours, previous methods face difficulties in finding the target in the query image with only limited target information. + +When some background is helpful: In some FSS cases, the background offers relevant context that is unavailable in the support mask, for accurate segmentation. However, many recent methods depend on support masks to completely remove the background. We notice the person class frequently exists in the background of the support image in PASCAL- $5^{i}$ [5]. Therefore, in order to empirically validate the importance of leveraging relevant background information, we train VAT+MSI and VAT [8] by removing the segmentation mask of the person class when the person exists in the background of the support image. We compare with or without the person class existing in the background of the support image in Tab. 8 and Fig. 7. After excluding the person class, the performance drop for VAT+MSI was much larger than VAT [8]. + +![](images/64eb3229b25a70a9bbc2b302fefdfbdd2c0534c446e0562fe160e23900e35cbd.jpg) +Figure 4. Visual comparison of VAT [8] and $\mathrm{VAT} + \mathrm{MSI}$ with ResNet50 [7] on PASCAL- $5^{i}$ [5] and COCO- $20^{i}$ [15]. + +![](images/3ded2caf7e53ad40f6950aab7234a4669594e64ab86659944fd55857c2a22e3b.jpg) +Figure 5. Comparison of $\mathrm{VAT} + \mathrm{MSI}$ on PASCAL- $5^{i}$ [5] with ResNet50 [7] using different kinds of features in SIF: SIF with only target features, SIF with only background features, and SIF with the entire image's features. + +![](images/3d8b79a81369c5f09c510e00aa14d70d7388d2bc50a9373fb7a9f15e46f34154.jpg) +Figure 6. Missing information around boundary on PASCAL- $5^{i}$ [5]. The mask is not perfect to cover entire target object. + +![](images/e4e847e66faeb0f675bf271531502790a73088f858dceb8dce241717e69241ed.jpg) +Figure 7. Comparison of performance when background information of support set is relevant to the background in the query image. Note that the person is in the background of the support image (target object is the ball). VAT failed to segment the ball correctly, while $\mathrm{VAT} + \mathrm{MSI}$ was able to differentiate the ball and people. + +# 4.3. Ablation Study and Analysis + +Why the masked support image is helpful: (1) Feature masking (FM) is utilized by several existing FSS models [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12], obtained by masking background features. The target features in FM are not merely targeted object features. When extracting target + +![](images/b8eb9b5cec82d4913a32029aa8017c1e468dcbd1ac248beaf9ce45469dd56077.jpg) +Figure 8. Feature map comparison between support target features (STF) and feature masking (FM). The cyan circles show that STF captures more fine-grained features near the target object boundary, however, FM struggles to capture the same. In deeper layers, the advantage of STF becomes more apparent (e.g. Block 3). + +![](images/e90bfa14d07590230f039259dc5abde5aeef00baeaab615ba84a3159f4a09c06.jpg) +Figure 9. Feature masking (FM) overlooks the impact of the growing receptive field. Background deep features could contain target object information. FM thus loses the detailed target information by masking all features using a support mask. This becomes severe when the support mask is small/inaccurate. + +features in FM, the features corresponding to background objects could also be present because of the enlarging receptive fields [20]. These background features interfere with obtaining target information. However, this interference can be eliminated by masking the background at the input image level in our MSI. (2) STF holds more target features such as the texture and boundary of the target object than FM. In contrast, FM loses such information by masking features to remove the background (Fig. 8) [22]. + +How MSI helps for each case: FM is utilized in most FSS works to remove the background in support features [34, 33, 31, 23, 35]. (a) When the support mask fails to mask the same target class in a different location, unlike FM, SIF in MSI can still retain the target information (Fig. 5). (b) When the target class is minuscule, FM features retain minimal target information from masking downstream features (Fig. 9). However, in MSI, we mask support images at the input level. As such, we can retain fine-grained information in STF. Also, SIF could hold the target information missed by STF due to a small mask (Tab. 8). (c) FM loses target boundary information (Fig. 6) when removing background features with an inaccurate mask. However, MSI can overcome this by exploiting additional target information in SIF and it facilitates a network in recovering fine-grained target details through the encoder/decoder. (d) FM cannot utilize the contextual features from the background. For example, if the support and query images have the same non-target object in the background, MSI uses $CS_{1}$ to learn contextual features and recognizes the same objects in QF and SIF, and $CS_{2}$ to find the similarity between STF and QF to learn target-specific features to locate the target object (Fig. 3, Eq. 3). Both $CS_{1}$ and $CS_{2}$ allow the network to recognize non-targets (Fig. 7, Tab. 8) and leverage such information. + +Best features for SCM: In Tab. 5, we show results when using various combinations of features to obtain SCM. For this purpose, VAT [8] with ResNet50 backbone is used as a baseline and PASCAL- $5^{i}$ is chosen for training and testing the model. The ablation study reveals that harnessing both SIF and STF via concatenation achieves the best mIoU. Please see the supplementary text for visualizations of the correlation value distributions for SIF and STF. + +On different ways of fusing SIF and STF: The proposed method, MSI, calculates cosine similarity between $\langle$ STF, QF $\rangle$ and $\langle$ SIF, QF $\rangle$ , and concatenates the two generated correlation maps. To see the effectiveness of this method, we experimented with different approaches to fuse SIF and STF to obtain SCM (see Tab. 6). Feature addition refers to the element-wise addition of features before calculating the cosine similarity to get the correlation map. Correlation addition means simply adding two correlation maps elementwise. The attention method merges two correlation maps through 1x1 depth-wise attention based on Attention U-Net [24]. Among all design choices for fusion, concatenating the two correlation maps showed the best performance. + +Fast training convergence: We notice that MSI with VAT [8] and ResNet50 on PASCAL- $5^{i}$ , $\mathrm{VAT} + \mathrm{MSI}$ , provides 3.3x faster convergence (i.e. to reach mIoU of $60\%$ ) on average than VAT (Fig. 10), along with a remarkable improvement in performance. Similarly with HSNet, HSNet+MSI allows faster convergence by 4.5x on average. See supplementary for plots. + +![](images/765c17047fb3bbd89bc616a4bf99967ed550a72caf145878b744cc7a14aefec4.jpg) +Figure 10. Train. and val. profiles of VAT [8] and $\mathrm{VAT} + \mathrm{MSI}$ on PASCAL- $5^{i}$ with ResNet50. $\mathrm{VAT} + \mathrm{MSI}$ provides $3.3\mathrm{x}$ faster convergence (to reach $60\%$ in mIoU) on average than VAT. Red circles indicate when the training accuracy reaches $60\%$ in mIoU. + +# 5. Conclusion + +We proposed a new method, MSI, maximizing the information of the support set, deviating from the masking method [37] widely used in many FSS models [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12]. The joint exploitation of SIF and STF develops a synergy between them, which allows handling several challenging FSS cases. The results show significant performance improvements across all benchmarks on recent, strong FSS baselines (HSNet [21], ASNet [11], and VAT [8]). + +# Acknowledgment + +This work is supported in part by NSF Grant #1955404 and #1955365. + +# References + +[1] Malik Boudiaf, Hoel Kervadec, Ziko Imtiaz Masud, Pablo Piantanida, Ismail Ben Ayed, and Jose Dolz. Few-Shot Segmentation Without Meta-Learning: A Good Transductive Inference Is All You Need? In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 13979-13988, June 2021. 6 +[2] Liang-Chieh Chen, George Papandreou, Iasonas Kokkinos, Kevin Murphy, and Alan L. Yuille. DeepLab: Semantic Image Segmentation with Deep Convolutional Nets, Atrous Convolution, and Fully Connected CRFs. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 40(4):834-848, 2018. 1 +[3] Seokju Cho, Sunghwan Hong, Sangryul Jeon, Yunsung Lee, Kwanghoon Sohn, and Seungryong Kim. CATs: Cost Aggregation Transformers for Visual Correspondence. In Proceedings of Advances in Neural Information Processing Systems (NeurIPS), 2021. 5 +[4] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. ImageNet: A large-scale hierarchical image database. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 248–255, 2009. 3, 5 +[5] Mark Everingham, Luc Van Gool, Christopher Williams, John Winn, and Andrew Zisserman. The Pascal Visual Ob- + +ject Classes (VOC) challenge. International Journal of Computer Vision (IJCV), 88:303-338, 06 2010. 1, 2, 5, 6, 7, 8 +[6] Xavier Glorot, Antoine Bordes, and Yoshua Bengio. Deep Sparse Rectifier Neural Networks. In Proceedings of the Fourteenth International Conference on Artificial Intelligence and Statistics (AISTAT), volume 15 of Proceedings of Machine Learning Research (PMLR), pages 315-323, Fort Lauderdale, FL, USA, 11-13 Apr 2011. 5 +[7] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep Residual Learning for Image Recognition. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 770-778, 2016. 3, 5, 6, 7, 8 +[8] Sunghwan Hong, Seokju Cho, Jisu Nam, and Seungryong Kim. Cost Aggregation Is All You Need for Few-Shot Segmentation. arXiv preprint arXiv:2112.11685, 2021. 2, 3, 5, 6, 7, 8, 9 +[9] Sunghwan Hong, Seokju Cho, Jisu Nam, Stephen Lin, and Seungryong Kim. Cost Aggregation with 4D Convolutional Swin Transformer for Few-Shot Segmentation. In Proceedings of European Conference on Computer Vision (ECCV), 2022. 1, 2, 3, 4, 5, 8, 9 +[10] M. Amirul Islam, M. Kowal, S. Jia, K. G. Derpanis, and N. B. Bruce. Global Pooling, More than Meets the Eye: Position Information is Encoded Channel-Wise in CNNs. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 773-781, 2021. 3 +[11] Dahiyun Kang and Minsu Cho. Integrative Few-Shot Learning for Classification and Segmentation. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 1, 2, 3, 4, 5, 6, 8, 9 +[12] C. Lang, G. Cheng, B. Tu, and J. Han. Learning what not to segment: A new perspective on few-shot segmentation. In 2022 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 8047-8057, Los Alamitos, CA, USA, jun 2022. IEEE Computer Society. 1, 2, 3, 4, 6, 8, 9 +[13] Gen Li, Varun Jampani, Laura Sevilla-Lara, Deqing Sun, Jonghyun Kim, and Joongkyu Kim. Adaptive Prototype Learning and Allocation for Few-Shot Segmentation. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2021. 1, 2, 3, 4, 5, 8, 9 +[14] Xiang Li, Tianhan Wei, Yau Pun Chen, Yu-Wing Tai, and Chi-Keung Tang. FSS-1000: A 1000-Class Dataset for Few-Shot Segmentation. Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2020. 2, 5, 6, 7 +[15] Tsung-Yi Lin, Michael Maire, Serge Belongie, Lubomir Bourdev, Ross Girshick, James Hays, Pietro Perona, Deva Ramanan, C. Lawrence Zitnick, and Piotr Dólar. Microsoft COCO: Common Objects in Context. In Proceedings of European Conference on Computer Vision (ECCV), 2014. 1, 2, 5, 6, 7, 8 +[16] Weide Liu, Chi Zhang, Henghui Ding, Tzu-Yi Hung, and Guosheng Lin. Few-shot Segmentation with Optimal Transport Matching and Message Flow. IEEE Transactions on Multimedia (TMM), 2022. 1, 2, 4, 5 + +[17] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin Transformer: Hierarchical Vision Transformer using Shifted Windows. In Proceedings of International Conference on Computer Vision (ICCV), 2021. 3 +[18] J. Long, E. Shelhamer, and T. Darrell. Fully convolutional networks for semantic segmentation. In 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3431-3440, Los Alamitos, CA, USA, jun 2015. IEEE Computer Society. 1 +[19] Zhihe Lu, Sen He, Xiatian Zhu, Li Zhang, Yi-Zhe Song, and Tao Xiang. Simpler is Better: Few-shot Semantic Segmentation with Classifier Weight Transformer. In Proceedings of International Conference on Computer Vision (ICCV), 2021. 1, 2, 6 +[20] Wenjie Luo, Yujia Li, Raquel Urtasun, and Richard Zemel. Understanding the effective receptive field in deep convolutional neural networks. In Proceedings of the 30th International Conference on Neural Information Processing Systems, NIPS'16, page 4905-4913, Red Hook, NY, USA, 2016. Curran Associates Inc. 4, 8 +[21] Juhong Min, Dahiyun Kang, and Minsu Cho. Hypercorrelation Squeeze for Few-Shot Segmentation. In Proceedings of International Conference on Computer Vision (ICCV), pages 6941-6952, 2021. 1, 2, 3, 4, 5, 6, 8, 9 +[22] Seonghyeon Moon, Samuel S. Sohn, Honglu Zhou, Sejong Yoon, Vladimir Pavlovic, Muhammad Haris Khan, and Mubasir Kapadia. HM: Hybrid Masking for Few-Shot Segmentation. In Proceedings of European Conference on Computer Vision (ECCV), pages 506-523, 2022. 1, 2, 3, 4, 5, 7, 8 +[23] Khoi Nguyen and Sinisa Todorovic. Feature Weighting and Boosting for Few-Shot Segmentation. In Proceedings of International Conference on Computer Vision (ICCV), 2019, 1, 2, 3, 4, 8, 9 +[24] Ozan Oktay, Jo Schlemper, Loic Le Folgoc, Matthew C. H. Lee, Mattias P. Heinrich, Kazunari Misawa, Kensaku Mori, Steven G. McDonagh, Nils Y. Hammerla, Bernhard Kainz, Ben Glocker, and Daniel Rueckert. Attention U-Net: Learning Where to Look for the Pancreas. In Medical Imaging with Deep Learning (MIDL), 2018. 5, 9 +[25] Kate Rakelly, Evan Shelhamer, Trevor Darrell, Alyosha A. Efros, and Sergey Levine. Conditional Networks for Few-Shot Semantic Segmentation. In Workshop Track Proceedings of International Conference on Learning Representations (ICLR), 2018. 1, 2 +[26] Joseph Redmon, Santosh Divvala, Ross Girshick, and Ali Farhadi. You only look once: Unified, Real-time Object Detection. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 779-788, 2016. 1 +[27] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster R-CNN: Towards Real-time Object Detection with Region Proposal Networks. Proceedings of Advances in Neural Information Processing Systems (NeurIPS), 28, 2015. 1 +[28] Amirreza Shaban, Shray Bansal, Zhen Liu, Irfan Essa, and Byron Boots. One-Shot Learning for Semantic Segmenta + +tion. In Proceedings of British Machine Vision Conference (BMVC), pages 167.1-167.13, 2017. 2, 4 +[29] Xinyu Shi, Dong Wei, Yu Zhang, Donghuan Lu, Munan Ning, Jiashun Chen, Kai Ma, and Yefeng Zheng. Dense cross-query-and-support attention weighted mask aggregation for few-shot segmentation. In Computer Vision - ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XX, page 151-168, 2022. 3, 6 +[30] Mennatullah Siam, Boris N. Oreshkin, and Martin Jägersand. AMP: Adaptive Masked Proxies for Few-Shot Segmentation. In Proceedings of International Conference on Computer Vision (ICCV), pages 5248-5257, 2019. 1, 2 +[31] Zhuotao Tian, Hengshuang Zhao, Michelle Shu, Zhicheng Yang, Ruiyu Li, and Jiaya Jia. Prior Guided Feature Enrichment Network for Few-Shot Segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 2020. 1, 2, 3, 4, 5, 8, 9 +[32] Haochen Wang, Xudong Zhang, Yutao Hu, Yandan Yang, Xianbin Cao, and Xiantong Zhen. Few-Shot Semantic Segmentation with Democratic Attention Networks. In Proceedings of European Conference on Computer Vision (ECCV), pages 730-746, 2020. 1, 2 +[33] Kaixin Wang, Jun Hao Liew, Yingtian Zou, Daquan Zhou, and Jiashi Feng. PANet: Few-Shot Image Semantic Segmentation With Prototype Alignment. In Proceedings of International Conference on Computer Vision (ICCV), 2019, 1, 2, 3, 4, 8, 9 +[34] Boyu Yang, Chang Liu, Bohao Li, Jianbin Jiao, and Ye Qixiang. Prototype Mixture Models for Few-shot Semantic Segmentation. In Proceedings of European Conference on Computer Vision (ECCV), 2020. 1, 2, 3, 4, 8, 9 +[35] Chi Zhang, Guosheng Lin, Fayao Liu, Rui Yao, and Chunhua Shen. CANet: Class-Agnostic Segmentation Networks With Iterative Refinement and Attentive Few-Shot Learning. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2019. 1, 2, 3, 4, 8, 9 +[36] Gengwei Zhang, Guoliang Kang, Yi Yang, and Yunchao Wei. Few-Shot Segmentation via Cycle-Consistent Transformer. arXiv preprint arXiv:2106.02320, 2021. 2, 3, 4, 6, 8, 9 +[37] Xiaolin Zhang, Yunchao Wei, Yi Yang, and Thomas Huang. SG-One: Similarity Guidance Network for One-Shot Semantic Segmentation. IEEE Transactions on Cybernetics, 50:3855-3865, 2020. 1, 2, 3, 4, 9 +[38] Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, and Jiaya Jia. Pyramid Scene Parsing Network. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 6230-6239, 2017. 1 \ No newline at end of file diff --git a/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/images.zip b/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..0659e16d20f23ba41139a49253168dd1a5d4943c --- /dev/null +++ b/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:53a41fb7e294af667b3fde1f8190c85b7a560543a63fba227e3c69a1f6943f4b +size 875262 diff --git a/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/layout.json b/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..a661f03551ea7ba197e4da037a94028bf4707dd2 --- /dev/null +++ b/2023/MSI_ Maximize Support-Set Information for Few-Shot Segmentation/layout.json @@ -0,0 +1,9524 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 84, + 103, + 510, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 84, + 103, + 510, + 121 + ], + "spans": [ + { + "bbox": [ + 84, + 103, + 510, + 121 + ], + "type": "text", + "content": "MSI: Maximize Support-Set Information for Few-Shot Segmentation" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 91, + 144, + 186, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 144, + 186, + 171 + ], + "spans": [ + { + "bbox": [ + 91, + 144, + 186, + 171 + ], + "type": "text", + "content": "Seonghyeon Moon\nRutgers University" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 89, + 174, + 189, + 184 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 89, + 174, + 189, + 184 + ], + "spans": [ + { + "bbox": [ + 89, + 174, + 189, + 184 + ], + "type": "text", + "content": "sm2062@rutgers.edu" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 235, + 144, + 326, + 172 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 235, + 144, + 326, + 172 + ], + "spans": [ + { + "bbox": [ + 235, + 144, + 326, + 172 + ], + "type": "text", + "content": "Samuel S. Sohn \nRutgers University" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 217, + 175, + 342, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 217, + 175, + 342, + 185 + ], + "spans": [ + { + "bbox": [ + 217, + 175, + 342, + 185 + ], + "type": "text", + "content": "samuel.sohn@rutgers.edu" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 369, + 144, + 504, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 369, + 144, + 504, + 171 + ], + "spans": [ + { + "bbox": [ + 369, + 144, + 504, + 171 + ], + "type": "text", + "content": "Honglu Zhou \nNEC Laboratories America" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 384, + 175, + 489, + 184 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 384, + 175, + 489, + 184 + ], + "spans": [ + { + "bbox": [ + 384, + 175, + 489, + 184 + ], + "type": "text", + "content": "hozhou@nec-labs.com" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 189, + 192, + 254, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 189, + 192, + 254, + 205 + ], + "spans": [ + { + "bbox": [ + 189, + 192, + 254, + 205 + ], + "type": "text", + "content": "Sejong Yoon" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 156, + 206, + 288, + 220 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 156, + 206, + 288, + 220 + ], + "spans": [ + { + "bbox": [ + 156, + 206, + 288, + 220 + ], + "type": "text", + "content": "The College of New Jersey" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 182, + 222, + 261, + 232 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 182, + 222, + 261, + 232 + ], + "spans": [ + { + "bbox": [ + 182, + 222, + 261, + 232 + ], + "type": "text", + "content": "yoons@tcnj.edu" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 336, + 192, + 428, + 220 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 336, + 192, + 428, + 220 + ], + "spans": [ + { + "bbox": [ + 336, + 192, + 428, + 220 + ], + "type": "text", + "content": "Vladimir Pavlovic \nRutgers University" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 327, + 221, + 436, + 232 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 221, + 436, + 232 + ], + "spans": [ + { + "bbox": [ + 327, + 221, + 436, + 232 + ], + "type": "text", + "content": "vladimir@rutgers.edu" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 69, + 239, + 346, + 267 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 239, + 346, + 267 + ], + "spans": [ + { + "bbox": [ + 69, + 239, + 346, + 267 + ], + "type": "text", + "content": "Muhammad Haris Khan \nMohamed Bin Zayed University of Artificial Intelligence" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 133, + 270, + 282, + 280 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 133, + 270, + 282, + 280 + ], + "spans": [ + { + "bbox": [ + 133, + 270, + 282, + 280 + ], + "type": "text", + "content": "muhammad.haris@mbzuai.ac.ae" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 400, + 239, + 493, + 267 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 400, + 239, + 493, + 267 + ], + "spans": [ + { + "bbox": [ + 400, + 239, + 493, + 267 + ], + "type": "text", + "content": "Mubbasir Kapadia \nRutgers University" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 370, + 270, + 523, + 281 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 370, + 270, + 523, + 281 + ], + "spans": [ + { + "bbox": [ + 370, + 270, + 523, + 281 + ], + "type": "text", + "content": "mubbasir.kapadia@rutgers.edu" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 143, + 308, + 191, + 321 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 308, + 191, + 321 + ], + "spans": [ + { + "bbox": [ + 143, + 308, + 191, + 321 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 47, + 334, + 290, + 561 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 334, + 290, + 561 + ], + "spans": [ + { + "bbox": [ + 47, + 334, + 290, + 561 + ], + "type": "text", + "content": "FSS (Few-shot segmentation) aims to segment a target class using a small number of labeled images (support set). To extract information relevant to the target class, a dominant approach in best performing FSS methods removes background features using a support mask. We observe that this feature excision through a limiting support mask introduces an information bottleneck in several challenging FSS cases, e.g., for small targets and/or inaccurate target boundaries. To this end, we present a novel method (MSI), which maximizes the support-set information by exploiting two complementary sources of features to generate super correlation maps. We validate the effectiveness of our approach by instantiating it into three recent and strong FSS methods. Experimental results on several publicly available FSS benchmarks show that our proposed method consistently improves performance by visible margins and leads to faster convergence. Our code and trained models are available at: https://github.com/moonsh/MSI-Maximize-Support-Set-Information" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 47, + 585, + 128, + 597 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 585, + 128, + 597 + ], + "spans": [ + { + "bbox": [ + 47, + 585, + 128, + 597 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 46, + 605, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 287, + 715 + ], + "type": "text", + "content": "Deep convolutional neural networks (DCNNs) have achieved state-of-the-art results across several mainstream computer vision (CV) problems, including object detection [26, 27] and semantic segmentation [18, 2, 38]. An important factor underlying the success of DCNNs is large-scale annotated datasets, which are costly and cumbersome to acquire in many dense prediction tasks, such as semantic segmentation. Moreover, these models struggle to segment novel objects when only a few annotated examples are" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 318, + 331, + 327, + 340 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 318, + 331, + 327, + 340 + ], + "spans": [ + { + "bbox": [ + 318, + 331, + 327, + 340 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 22 + }, + { + "type": "image", + "bbox": [ + 333, + 308, + 533, + 495 + ], + "blocks": [ + { + "bbox": [ + 333, + 308, + 533, + 495 + ], + "lines": [ + { + "bbox": [ + 333, + 308, + 533, + 495 + ], + "spans": [ + { + "bbox": [ + 333, + 308, + 533, + 495 + ], + "type": "image", + "image_path": "c29d178004acd6070f5e01dc9699b87f415ed6e6d2f369282e92888ffcdc82a9.jpg" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 498, + 547, + 641 + ], + "lines": [ + { + "bbox": [ + 304, + 498, + 547, + 641 + ], + "spans": [ + { + "bbox": [ + 304, + 498, + 547, + 641 + ], + "type": "text", + "content": "Figure 1. Recent FSS baseline (VAT[9]) struggles to accurately segment the target object in several challenging scenarios in PASCAL [5] and " + }, + { + "bbox": [ + 304, + 498, + 547, + 641 + ], + "type": "inline_equation", + "content": "\\mathrm{COCO}^i" + }, + { + "bbox": [ + 304, + 498, + 547, + 641 + ], + "type": "text", + "content": " [15]: (a) the same instance of the target class is not masked, e.g., the sofa on the right, (b) the support mask is very small compared to the entire image, e.g., flowers in the pot, (c) support mask is missing some target boundary information, e.g., the front and chimney of the train, and (d) the background contains some important contextual information, unavailable in the support mask, e.g., shoes and grass. Our method (MSI) is capable of accurately segmenting target objects. It maximizes the support set information to compensate for the limited support mask information and can exploit relevant contextual information from the background." + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_caption" + } + ], + "index": 23 + }, + { + "bbox": [ + 305, + 665, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 665, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 305, + 665, + 547, + 715 + ], + "type": "text", + "content": "available. Many existing few-shot segmentation (FSS) approaches [25, 30, 34, 23, 31, 33, 35, 13, 32, 16, 37, 19, 21, 11, 12, 9, 22] aim to address this shortcoming. The problem settings in FSS require accurate segmentation of a target ob" + } + ] + } + ], + "index": 25 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "19266" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 62, + 71, + 258, + 148 + ], + "blocks": [ + { + "bbox": [ + 62, + 71, + 258, + 148 + ], + "lines": [ + { + "bbox": [ + 62, + 71, + 258, + 148 + ], + "spans": [ + { + "bbox": [ + 62, + 71, + 258, + 148 + ], + "type": "image", + "image_path": "f0d470f213d76468e071e8e9bc82cb6c1945c1b775be733ee3345b61edffdbbf.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 61, + 152, + 275, + 227 + ], + "blocks": [ + { + "bbox": [ + 61, + 152, + 275, + 227 + ], + "lines": [ + { + "bbox": [ + 61, + 152, + 275, + 227 + ], + "spans": [ + { + "bbox": [ + 61, + 152, + 275, + 227 + ], + "type": "image", + "image_path": "6fd00709779a12f4c7e062650f4900735b403bd52b695f959c2ea943a88b5072.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 61, + 232, + 275, + 306 + ], + "blocks": [ + { + "bbox": [ + 61, + 232, + 275, + 306 + ], + "lines": [ + { + "bbox": [ + 61, + 232, + 275, + 306 + ], + "spans": [ + { + "bbox": [ + 61, + 232, + 275, + 306 + ], + "type": "image", + "image_path": "ea065c0dcf99bb48f1ac21ed1012e5f370231929e8b3bc75fc28334d78109dc4.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 309, + 287, + 397 + ], + "lines": [ + { + "bbox": [ + 46, + 309, + 287, + 397 + ], + "spans": [ + { + "bbox": [ + 46, + 309, + 287, + 397 + ], + "type": "text", + "content": "Figure 2. (a) Many FSS methods use support mask to remove background features [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12], denoted as feature masking (FM), and so rely only on target object features. (b) Recent work, HM [22], merges both image masking and feature masking to achieve hybrid masking for improving target information. (c) We propose to maximize the support set information (MSI) to compensate for the limited support mask information and exploit relevant contextual information from the background." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 422, + 286, + 445 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 422, + 286, + 445 + ], + "spans": [ + { + "bbox": [ + 46, + 422, + 286, + 445 + ], + "type": "text", + "content": "ject in a query image, given few annotated images, termed the support set, from the target class." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 448, + 286, + 638 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 448, + 286, + 638 + ], + "spans": [ + { + "bbox": [ + 46, + 448, + 286, + 638 + ], + "type": "text", + "content": "Shaban et al.'s work [28] introduced the first FSS model, in which a masked support image was used to extract only the target features. Using the target features, both segmentation and conditioning branches are trained to segment an object of the target class. Later, Zhang et al. [37] show that extracting target features using masked average pooling (MAP) is more beneficial for network learning than obtaining features by masking images. Since then, many FSS models [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12] have considered MAP as the de facto technique for obtaining target features and focus on improving the encoder/decoder network. Recently, HSNet [21] proposed to utilize more effective target features extracted from multiple layers of a deep backbone network. Likewise, ASNet [11] and VAT [9] proposed different network architectures to harness deep features." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 642, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 286, + 713 + ], + "type": "text", + "content": "Despite promising results, many recent methods, including HSNet [21], ASNet [11], and VAT [9], systematically struggle with few challenging FSS cases (Fig. 1): (a) When the support mask does not mask all instances of the same target class; (b) The support mask is unable to faithfully capture object boundaries; (c) The support mask is too" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": "small, carrying limited object information; and (d) The background contains some important contextual information, unavailable in the support mask, for accurately segmenting the target object. We conjecture that this happens because many current SOTA methods rely on support masks to completely remove the background (Fig. 2), which limits the useful information in several challenging FSS cases." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 157, + 545, + 357 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 157, + 545, + 357 + ], + "spans": [ + { + "bbox": [ + 304, + 157, + 545, + 357 + ], + "type": "text", + "content": "In this paper, we propose a new method to overcome the limited information bottleneck from the support mask. It is based on the intuition that upon maximizing the information from the masked support set images (MSI), it is possible to compensate for the limited support mask information by utilizing the important contextual information available in the typically discarded background (Fig. 2). MSI jointly exploits two complementary sources of features. The first set of features is obtained by using masked support images, which only activate the target-related features in the query image. The second set of features is generated from the full support images, which activate the features of all similar objects shared between the support and query images. The former features act as an anchor for the latter in localizing a certain target class while supplementing it with the target boundary information. We summarize our key contributions as follows:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 317, + 359, + 545, + 526 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 317, + 359, + 545, + 418 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 359, + 545, + 418 + ], + "spans": [ + { + "bbox": [ + 317, + 359, + 545, + 418 + ], + "type": "text", + "content": "- We propose MSI, an efficient and effective plug-and-play module for FSS methods. MSI harnesses masked support images to capture the delineated target information and exploits the entire support image for complete target information." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 317, + 419, + 545, + 491 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 419, + 545, + 491 + ], + "spans": [ + { + "bbox": [ + 317, + 419, + 545, + 491 + ], + "type": "text", + "content": "- We perform extensive experiments and analysis on three challenging FSS benchmarks: PASCAL-" + }, + { + "bbox": [ + 317, + 419, + 545, + 491 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 317, + 419, + 545, + 491 + ], + "type": "text", + "content": " [5], COCO-" + }, + { + "bbox": [ + 317, + 419, + 545, + 491 + ], + "type": "inline_equation", + "content": "20^{i}" + }, + { + "bbox": [ + 317, + 419, + 545, + 491 + ], + "type": "text", + "content": " [15], and FSS-1000 [14]. Results show that MSI consistently improves mIoU in the one-shot setting over all strong baselines, including HSNet [21], ASNet [11], and VAT [9]." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 317, + 491, + 545, + 526 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 491, + 545, + 526 + ], + "spans": [ + { + "bbox": [ + 317, + 491, + 545, + 526 + ], + "type": "text", + "content": "- MSI improves the training speed of recent baseline models on PASCAL-5" + }, + { + "bbox": [ + 317, + 491, + 545, + 526 + ], + "type": "inline_equation", + "content": "^i" + }, + { + "bbox": [ + 317, + 491, + 545, + 526 + ], + "type": "text", + "content": " [5], with 3.3x average speed-up on VAT [8] and 4.5x on HSNet [21]." + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 538, + 397, + 550 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 538, + 397, + 550 + ], + "spans": [ + { + "bbox": [ + 306, + 538, + 397, + 550 + ], + "type": "text", + "content": "2. Related Works" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 558, + 545, + 629 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 545, + 629 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 545, + 629 + ], + "type": "text", + "content": "Few-shot segmentation: OSLSM [28] is considered to be the first work introducing FSS problem. OSLSM proposed a model consisting of a condition branch and a segmentation branch. Since OSLSM, various methods have been proposed to solve the FSS problem [25, 30, 34, 23, 31, 33, 35, 13, 32, 16, 37, 19, 21, 11, 12, 9, 22]." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "text", + "content": "MAP (Masked Average Pooling): Zhang et al. [37] proposed the MAP to collect target information from the support set. MAP masks features instead of masking support images and uses average pooling to extract target information. They argued that (1) removing the background from support images increases the variance of the input data for a unified network and (2) masking the im" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19267" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 191 + ], + "type": "text", + "content": "age will make the network biased toward the target image. For these reasons, MAP was recommended to get target features. Since Zhang et al. [37], many few shot works [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12] are following MAP to extract target features. However, by performing average pooling, spatial information is inevitably lost [10]. In this work, we utilized the masked support image to generate target features without using MAP. Therefore, we can retrieve fine-detail texture information and preserve spatial information." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 194, + 289, + 386 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 194, + 289, + 386 + ], + "spans": [ + { + "bbox": [ + 46, + 194, + 289, + 386 + ], + "type": "text", + "content": "Multi-layer features: Instead of using MAP, HSNet [21] proposed to use deep features extracted from multiple layers and designed an effective convolution to process the features. To process the deep features effectively and efficiently, VAT [8] proposed a model based on the swim transformer [17] and ASNet [11] proposed the attentive squeeze network. HM [22] proposed hybrid masking to compensate for the lost details in feature masking. Although the spatial information that MAP lost was preserved, these works extracted target features counting on support masks. Therefore, when the support masks give limited information, limited target information is extracted. In this paper, not only is information loss minimized when the target features are extracted by relying on the support mask, but also more meaningful target features are extracted by utilizing both the entire support image and the masked support image." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 388, + 289, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 388, + 289, + 616 + ], + "spans": [ + { + "bbox": [ + 46, + 388, + 289, + 616 + ], + "type": "text", + "content": "Utilizing background information: There have been several attempts to improve FSS accuracy by using background information [34, 12]. PMM [34] proposed a method of deactivating the background and activating the target object using a duplex manner. Negative learning was carried out with objects in the background, and on the other hand, positive learning was conducted using the foreground object. Afterward, the two learning results were used to segment the target object accurately. Similarly, BAM [12] also proposed to use two learners. The base learner was trained using objects in the background and a meta learner was trained with the foreground object. These two learners were integrated to predict segmentation accurately. However, they assumed that the background lacks meaningful target information. Therefore, they missed target information that might exist in the background. We obtain even more target information from the background and simultaneously utilize background information to avoid segmenting wrong objects." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 617, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 289, + 715 + ], + "type": "text", + "content": "Cross attention: Both CyCTR [36] and DCAMA [29] utilize the transformer architecture to achieve cross-attention between the support and query features. This cross-attention allows the identification of target information beyond the mask area. Despite this, both methods rely on an unmasked support image to extract target information, leading to the loss of delineated detailed target information. On the contrary, MSI proposes to directly provide the model" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 304, + 72, + 547, + 168 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 168 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 168 + ], + "type": "text", + "content": "with features from the masked support image and the full support image, thereby introducing a strong inductive bias that ultimately leads to better performance. MSI computes the cosine similarity between these two complementary sets of features and concatenates them. Therefore, MSI can retain detailed target information. It is more intuitive and simpler and can be plugged seamlessly into various FSS baselines, as validated in our experiments." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 306, + 177, + 403, + 190 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 177, + 403, + 190 + ], + "spans": [ + { + "bbox": [ + 306, + 177, + 403, + 190 + ], + "type": "text", + "content": "3. Overall Method" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 197, + 547, + 437 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 197, + 547, + 437 + ], + "spans": [ + { + "bbox": [ + 304, + 197, + 547, + 437 + ], + "type": "text", + "content": "Fig. 3 displays the overall architecture of our method. Following recent works [21, 11, 9], it consists of a backbone network (ResNet-50 [7] or ResNet-101 [7]) pre-trained on ImageNet [4] to obtain multi-layer features, and an encoder/decoder network to predict the segmentation mask. We propose a new plug-and-play module to maximize the support set information (MSI), which compensates for limited support mask information by exploiting relevant contextual information from the background. MSI extracts support target features (STF), containing delineated target class information from the support images, and support image features (SIF), accounting for the information in the entire support image. Next, STF and SIF are leveraged to obtain their respective correlation maps by computing the cosine similarity with respect to the query features (QF) obtained from the query image. Then, the correlation maps corresponding to STF and SIF are utilized to get super correlation maps (SCM). Finally, this SCM is used as the input to the encoder and decoder which can be from recent FSS methods (e.g., [21], [9], and [11])." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 443, + 392, + 455 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 443, + 392, + 455 + ], + "spans": [ + { + "bbox": [ + 306, + 443, + 392, + 455 + ], + "type": "text", + "content": "3.1. Preliminaries" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 461, + 547, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 461, + 547, + 521 + ], + "spans": [ + { + "bbox": [ + 304, + 461, + 547, + 521 + ], + "type": "text", + "content": "The goal of few-shot segmentation is to train a model that can segment the target object in a query image when provided with a few annotated example images from the target class. Following prior work in FSS [21, 11, 9], we utilize the episodic scheme for training our model." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": "Specifically, we assume the availability of two disjoint sets, " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "C_{train}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "C_{test}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " as training and testing classes, respectively. The training data " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "D_{train}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " is sampled from " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "C_{train}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " and the testing data " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "D_{test}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " is from " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "C_{test}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": ". We then construct multiple episodes from " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "D_{train}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "D_{test}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": ". An episode is comprised of a support set, " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "S = (I^s, M^s)" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": ", and a query set, " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "Q = (I^q, M^q)" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "I^*" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "M^*" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " denote an image and its corresponding mask. Furthermore, " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "D_{train} = \\{(S_i, Q_i)\\}_{i=1}^{N_{train}}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "D_{test} = \\{(S_i, Q_i)\\}_{i=1}^{N_{test}}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "N_{train}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " represents the number of episodes for training and " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "N_{test}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " is the number of episodes for testing. During training, we iteratively sample episodes from " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "D_{train}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " to train a model that learns a mapping from " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "(I^s, M^s, I^q)" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " to query mask " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "M^q" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": ". The learned model is used without further optimization by randomly sampling episodes from the testing data " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "D_{test}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " in the same manner and comparing the predicted query masks to the ground truth." + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19268" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 90, + 70, + 390, + 218 + ], + "blocks": [ + { + "bbox": [ + 90, + 70, + 390, + 218 + ], + "lines": [ + { + "bbox": [ + 90, + 70, + 390, + 218 + ], + "spans": [ + { + "bbox": [ + 90, + 70, + 390, + 218 + ], + "type": "image", + "image_path": "517280b1a0d18b5736c3ca7e96103b434df1c87440015071ad4acef8ff5e6350.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 221, + 545, + 299 + ], + "lines": [ + { + "bbox": [ + 46, + 221, + 545, + 299 + ], + "spans": [ + { + "bbox": [ + 46, + 221, + 545, + 299 + ], + "type": "text", + "content": "Figure 3. Overall architecture. To maximize the usability of the support set, first we extract support image features (SIF) and support target features (STF) through the backbone. SIF branch creates features using the entire support image, and STF branch extracts the features after removing background pixels. The query features (QF) are obtained from the query. We obtain correlation maps by calculating the cosine similarity (CS) of the STF and SIF with the QF, respectively, and these correlation maps are concatenated to make super correlation maps (SCM). " + }, + { + "bbox": [ + 46, + 221, + 545, + 299 + ], + "type": "inline_equation", + "content": "CS_2" + }, + { + "bbox": [ + 46, + 221, + 545, + 299 + ], + "type": "text", + "content": " represents the cosine similarity between the target object and the query image. Therefore, only target-related information in the query image will be activated. " + }, + { + "bbox": [ + 46, + 221, + 545, + 299 + ], + "type": "inline_equation", + "content": "CS_1" + }, + { + "bbox": [ + 46, + 221, + 545, + 299 + ], + "type": "text", + "content": ", on the other hand, assesses the cosine similarity between the entire support image and the query image. Consequently, all the similar objects between the support image and the query image are activated." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 398, + 71, + 504, + 217 + ], + "blocks": [ + { + "bbox": [ + 398, + 71, + 504, + 217 + ], + "lines": [ + { + "bbox": [ + 398, + 71, + 504, + 217 + ], + "spans": [ + { + "bbox": [ + 398, + 71, + 504, + 217 + ], + "type": "image", + "image_path": "778e68e85738e753d0cbc0cd70b6ccfae1ae97589b11cf873941735e943c6888.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 318, + 272, + 330 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 318, + 272, + 330 + ], + "spans": [ + { + "bbox": [ + 47, + 318, + 272, + 330 + ], + "type": "text", + "content": "3.2. Maximizing Support-Set Information: MSI" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 338, + 286, + 506 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 338, + 286, + 506 + ], + "spans": [ + { + "bbox": [ + 46, + 338, + 286, + 506 + ], + "type": "text", + "content": "An important question for the FSS pipeline is where in a network it is most suitable to use masking to provide target information to the network. Earlier attempts, such as the work of Shaban et al. [28] suggested masking the background in the input image so that only target features are obtained. The rationale was that the network would supposedly be biased toward large objects, so removing the background would decrease the variance of the output parameters. Later, Zhang et al. [37] proposed to mask the background after extracting features because masking the input image makes a network biased towards the target image and changes the statistical distribution of the support image set. Many recent state-of-the-art methods have conformed to this approach [34, 33, 31, 23, 35, 16, 13, 36, 21, 9, 11, 12]." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 508, + 286, + 639 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 508, + 286, + 639 + ], + "spans": [ + { + "bbox": [ + 46, + 508, + 286, + 639 + ], + "type": "text", + "content": "Motivation: Although these methods report promising performance, we note that many recent methods, including HSNet [21], ASNet [11], and VAT [9], struggle to accurately predict the segmentation mask in several challenging scenarios (Fig. 1). We believe that this occurs because many recent FSS methods fully rely on the support mask to remove the background features (Fig. 2). These support masks likely present an information bottleneck in such challenging cases. For instance, when they are very small, they fail to properly encapsulate target object boundaries or do not capture all instances of the target object." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 642, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 286, + 713 + ], + "type": "text", + "content": "We put forth a new approach (MSI) to alleviate the aforementioned limitations of support masks. We believe that by maximizing the information from support images, it becomes possible to compensate for the limited information in the support mask and also leverage important contextual information available in the background. Specifically, we" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 318, + 545, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 318, + 545, + 544 + ], + "spans": [ + { + "bbox": [ + 304, + 318, + 545, + 544 + ], + "type": "text", + "content": "extract support target features (STF), which contain delineated target class information in the support image, and support image features (SIF), which contain contextualized information from the entire support image. This is because the STF enables the acquisition of more focused and fine-grained target information, and compared to feature masking (Fig. 2) STF captures more accurate object boundaries because the receptive field can cover even the area beyond target object at deep features [20, 22]. On the other hand, SIF utilizes the full support image to capture relevant and useful target information that exists in the background. This allows us to obtain both detailed and complete information about the target class to avoid segmenting wrong objects. We leverage STF and SIF to obtain their respective correlation maps by computing their cosine similarity with the query features (QF), which are obtained from the query image. The correlation maps corresponding to STF and SIF are then combined into Super Correlation Maps (SCM), which are inputted to the encoder and decoder." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "spans": [ + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "text", + "content": "Formalizing STF and SIF: Support image features (SIF), " + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "inline_equation", + "content": "\\alpha_{i=1}^{N}" + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "text", + "content": " is the number of features, refer to the features of the entire support image, " + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "inline_equation", + "content": "I^{S} \\in \\mathbb{R}^{3 \\times w \\times h}" + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "text", + "content": " is the width and " + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "inline_equation", + "content": "h" + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "text", + "content": " is the height of the image. Support target features (STF), " + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "inline_equation", + "content": "\\beta_{i=1}^{N}" + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "text", + "content": ", are the features from the target image, " + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "inline_equation", + "content": "I^{T} \\in \\mathbb{R}^{3 \\times w \\times h}" + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "text", + "content": ", which is a masked support image using support mask " + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "inline_equation", + "content": "\\mathbf{M}^{S} \\in \\{0,1\\}^{w \\times h}" + }, + { + "bbox": [ + 304, + 546, + 545, + 630 + ], + "type": "text", + "content": ". Formally," + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 384, + 639, + 545, + 654 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 384, + 639, + 545, + 654 + ], + "spans": [ + { + "bbox": [ + 384, + 639, + 545, + 654 + ], + "type": "interline_equation", + "content": "I ^ {T} = I ^ {S} \\odot \\zeta (M ^ {S}), \\tag {1}", + "image_path": "077d2c30e51ff482e65544defe6e181eceb64cff6f633cc1504f2c02d9b8d84e.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "inline_equation", + "content": "\\zeta (\\cdot)" + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "text", + "content": " resizes the mask " + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "inline_equation", + "content": "M^S" + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "text", + "content": " to fit the dimension of the image " + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "inline_equation", + "content": "I^{S}" + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "inline_equation", + "content": "\\odot" + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "text", + "content": " denotes the Hadamard product. Query features (QF), " + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "inline_equation", + "content": "\\kappa_{i = 1}^{N}" + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "text", + "content": " , are obtained from the query image, " + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "inline_equation", + "content": "I^Q\\in \\mathbb{R}^{3\\times w\\times h}" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19269" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "type": "text", + "content": "For each image " + }, + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "type": "inline_equation", + "content": "(I^S, I^T, \\text{and} I^Q)" + }, + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "type": "text", + "content": ", the backbone network, " + }, + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "type": "inline_equation", + "content": "\\triangleleft" + }, + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "type": "text", + "content": ", produces " + }, + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "type": "text", + "content": " number of features " + }, + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "type": "inline_equation", + "content": "(\\alpha_{i=1}^N, \\beta_{i=1}^N, \\text{and} \\kappa_{i=1}^N" + }, + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "type": "text", + "content": " respectively) from its intermediate layers." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 61, + 115, + 287, + 133 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 115, + 287, + 133 + ], + "spans": [ + { + "bbox": [ + 61, + 115, + 287, + 133 + ], + "type": "interline_equation", + "content": "\\alpha_ {i = 1} ^ {N} = \\triangleleft (I ^ {S}), \\beta_ {i = 1} ^ {N} = \\triangleleft (I ^ {T}), \\kappa_ {i = 1} ^ {N} = \\triangleleft (I ^ {Q}), (2)", + "image_path": "0a75b3c8e86ec3d97a9e92a95a88e25fd92f4e5a31bacae4adf38d48de6ce60d.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 140, + 287, + 187 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 140, + 287, + 187 + ], + "spans": [ + { + "bbox": [ + 47, + 140, + 287, + 187 + ], + "type": "text", + "content": "where features, " + }, + { + "bbox": [ + 47, + 140, + 287, + 187 + ], + "type": "inline_equation", + "content": "\\alpha_{i},\\beta_{i},\\kappa_{i}\\in \\mathbb{R}^{c_{i}\\times w_{i}\\times h_{i}}" + }, + { + "bbox": [ + 47, + 140, + 287, + 187 + ], + "type": "text", + "content": " , have different sizes of channel and spatial dimensions. Features extracted from deeper layers have a large number of channels with smaller width and height dimensions." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "spans": [ + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "text", + "content": "Super Correlation Maps (SCM): We calculate the cosine similarities of " + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "inline_equation", + "content": "\\alpha_{i=1}^{N}" + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "inline_equation", + "content": "\\beta_{i=1}^{N}" + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "text", + "content": " with respect to " + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "inline_equation", + "content": "\\kappa_{i=1}^{N}" + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "text", + "content": " using the Eq. 3 to get correlation maps " + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "inline_equation", + "content": "C_i \\in \\mathbb{R}^{1 \\times w_i \\times h_i \\times w_i \\times h_i}" + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "inline_equation", + "content": "S_i \\in \\mathbb{R}^{1 \\times w_i \\times h_i \\times w_i \\times h_i}" + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "text", + "content": ". To perform multiplication between features, we reshape and transpose the features, " + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "inline_equation", + "content": "\\alpha_{i=1}^{N}, \\beta_{i=1}^{N}" + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "inline_equation", + "content": "\\kappa_{i=1}^{N}" + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "text", + "content": " into " + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "inline_equation", + "content": "\\alpha_{i=1}^{\\prime N} \\in \\mathbb{R}^{(w_i \\cdot h_i) \\times c_i}" + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "inline_equation", + "content": "\\beta_{i=1}^{\\prime N} \\in \\mathbb{R}^{(w_i \\cdot h_i) \\times c_i}" + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "inline_equation", + "content": "\\kappa_{i=1}^{\\prime N} \\in \\mathbb{R}^{c_i \\times (w_i \\cdot h_i)}" + }, + { + "bbox": [ + 47, + 188, + 287, + 276 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 77, + 283, + 287, + 318 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 77, + 283, + 287, + 318 + ], + "spans": [ + { + "bbox": [ + 77, + 283, + 287, + 318 + ], + "type": "interline_equation", + "content": "C S _ {1} = C _ {i = 1} ^ {N} = \\operatorname {R e L U} \\left(\\frac {\\alpha_ {i = 1} ^ {\\prime N} \\cdot \\kappa_ {i = 1} ^ {\\prime N}}{\\| \\alpha_ {i = 1} ^ {\\prime N} \\| \\| \\kappa_ {i = 1} ^ {\\prime N} \\|}\\right), \\tag {3}", + "image_path": "6eb5beae6453b0b7683a713d900cb2486d12756d56c765189cc98ab239ac9486.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 78, + 315, + 256, + 345 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 78, + 315, + 256, + 345 + ], + "spans": [ + { + "bbox": [ + 78, + 315, + 256, + 345 + ], + "type": "interline_equation", + "content": "C S _ {2} = S _ {i = 1} ^ {N} = \\mathrm {R e L U} \\bigg (\\frac {\\beta_ {i = 1} ^ {\\prime N} \\cdot \\kappa_ {i = 1} ^ {\\prime N}}{\\| \\beta_ {i = 1} ^ {\\prime N} \\| \\| \\kappa_ {i = 1} ^ {\\prime N} \\|} \\bigg),", + "image_path": "7ce6f2cb2e668bccce80add2197db11eea858cfb0245c761f508cbb62f693fff.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "spans": [ + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "text", + "content": " the is number of features and ReLU [6] removes inactivated and noisy values in the correlation map " + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "inline_equation", + "content": "C_i" + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "inline_equation", + "content": "S_{i}" + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "text", + "content": ". Correlation maps " + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "inline_equation", + "content": "C_{i = 1}^{N}" + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "inline_equation", + "content": "S_{i = 1}^{N}" + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "text", + "content": " are concatenated along the first dimension to obtain the Super Correlation Maps (SCM), " + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "inline_equation", + "content": "P_{i = 1}^{N}\\in \\mathbb{R}^{2\\times w_{i}\\times h_{i}\\times w_{i}\\times h_{i}}" + }, + { + "bbox": [ + 47, + 351, + 287, + 413 + ], + "type": "text", + "content": " (Eq. 4)." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 99, + 418, + 287, + 435 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 99, + 418, + 287, + 435 + ], + "spans": [ + { + "bbox": [ + 99, + 418, + 287, + 435 + ], + "type": "interline_equation", + "content": "S C M = P _ {i = 1} ^ {N} = \\left[ C _ {i = 1} ^ {N} \\oplus S _ {i = 1} ^ {N} \\right], \\tag {4}", + "image_path": "23aac561514aeab2a41d972923da443fb2e01f84a127cf270b8d035110cc1ee3.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 442, + 193, + 453 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 442, + 193, + 453 + ], + "spans": [ + { + "bbox": [ + 47, + 442, + 193, + 453 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 442, + 193, + 453 + ], + "type": "inline_equation", + "content": "\\oplus" + }, + { + "bbox": [ + 47, + 442, + 193, + 453 + ], + "type": "text", + "content": " denotes the concatenation." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 461, + 234, + 473 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 461, + 234, + 473 + ], + "spans": [ + { + "bbox": [ + 47, + 461, + 234, + 473 + ], + "type": "text", + "content": "3.3. Encoder and Decoder Architecture" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 479, + 287, + 599 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 479, + 287, + 599 + ], + "spans": [ + { + "bbox": [ + 47, + 479, + 287, + 599 + ], + "type": "text", + "content": "SCM can be fed as input to any encoder and decoder architecture of FSS methods. In order to validate our proposed method, we experiment with feeding SCM as input to three recent and strong encoder-decoder based FSS methods: HSNet [21], ASNet [11], and VAT [8]. For HSNet and VAT, the input channel size of the encoder in the models was doubled. For ASNet, SCM is merged using depth-wise attention based on Attention U-Net [24] instead of changing the input channel size. Otherwise, the architectures of the models were unchanged." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 609, + 128, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 609, + 128, + 623 + ], + "spans": [ + { + "bbox": [ + 47, + 609, + 128, + 623 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "text", + "content": "Datasets: We use three widely used and publicly available datasets for evaluating our method (MSI): PASCAL- " + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "text", + "content": " [5], COCO- " + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "20^{i}" + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "text", + "content": " [15] and FSS-1000 [14]. PASCAL- " + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "text", + "content": " consists of 20 classes, whereas COCO- " + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "20^{i}" + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "text", + "content": " has 100 classes and FSS-1000 contains 1000 classes. Following previous works [21, 11, 9], we cross validate using 4 folds for PASCAL- " + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "text", + "content": " and COCO- " + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "20^{i}" + }, + { + "bbox": [ + 47, + 629, + 287, + 713 + ], + "type": "text", + "content": " and we divide the classes into 4" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "type": "text", + "content": "groups for training and testing. Therefore, 5 and 20 classes are used for each fold testing on PASCAL- " + }, + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "type": "text", + "content": " and COCO" + }, + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "type": "inline_equation", + "content": "20^{i}" + }, + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "type": "text", + "content": ", respectively. Other remaining classes are used for training. For FSS-1000, 1000 classes are divided into 520, 240 and 240 for the training, validation and testing. Lastly, in order to evaluate the generalizability of our method, COCO" + }, + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "type": "inline_equation", + "content": "20^{i}" + }, + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "type": "text", + "content": " is used for training, and PASCAL- " + }, + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "type": "text", + "content": " for testing. To avoid class overlapping between training and testing, following previous works [21, 31], we change the PASCAL- " + }, + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 304, + 72, + 545, + 191 + ], + "type": "text", + "content": " class order for each fold." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 192, + 546, + 395 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 192, + 546, + 395 + ], + "spans": [ + { + "bbox": [ + 304, + 192, + 546, + 395 + ], + "type": "text", + "content": "Implementation details: We incorporate MSI into three baseline models, HSNet [21], VAT [8], and ASNet [11], and refer to them as HSNet + MSI, ASNet + MS and VAT + MSI. The backbone networks, ResNet50 [7] and ResNet101 [7], are pre-trained on ImageNet [4], and are used to extract deep features following HSNet, ASNet, and VAT (features from conv3_x to conv5_x before the ReLU [6] activation of each layer stacked to form the deep features). No fine-tuning of backbones was performed. For a fair comparison with the existing models, we keep their default hyperparameters, as listed in their codebases. For VAT training, CATs data augmentation [3] was used and the batch size was reduced due to GPU memory limitations. Specifically, the batch sizes 4, 8, and 4 were used for PASCAL" + }, + { + "bbox": [ + 304, + 192, + 546, + 395 + ], + "type": "inline_equation", + "content": "^{5^i}" + }, + { + "bbox": [ + 304, + 192, + 546, + 395 + ], + "type": "text", + "content": " [5], COCO-20" + }, + { + "bbox": [ + 304, + 192, + 546, + 395 + ], + "type": "inline_equation", + "content": "^{i}" + }, + { + "bbox": [ + 304, + 192, + 546, + 395 + ], + "type": "text", + "content": " [15], and FSS-1000 [14] respectively. No data augmentation was employed for training HSNet + MSI and ASNet + MSI." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 396, + 545, + 456 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 396, + 545, + 456 + ], + "spans": [ + { + "bbox": [ + 304, + 396, + 545, + 456 + ], + "type": "text", + "content": "Super-correlation maps for K-Shots>1: Given a query image and K support-set images, we compute SCM for each query-support pair, resulting in K SCMs and K corresponding mask predictions from the model. All predictions are summed and normalized by the highest score [21, 11, 9]." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "spans": [ + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "type": "text", + "content": "Evaluation metrics: We report FSS performance using mean Intersection-over-Union (mIoU) and Foreground and Background IoU (FB-IoU), which are widely used by existing methods [16, 31, 13, 21, 11, 9, 22]. We calculate mIoU = " + }, + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "type": "inline_equation", + "content": "\\frac{1}{n}\\sum_{1}^{n}IoU" + }, + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "type": "text", + "content": " is the number of test cases and FB-IoU = " + }, + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "type": "inline_equation", + "content": "\\frac{1}{2}(IoU_F + IoU_B)" + }, + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "type": "text", + "content": " is foreground and " + }, + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "type": "inline_equation", + "content": "B" + }, + { + "bbox": [ + 304, + 457, + 545, + 540 + ], + "type": "text", + "content": " is background without considering classes." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 550, + 362, + 562 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 550, + 362, + 562 + ], + "spans": [ + { + "bbox": [ + 306, + 550, + 362, + 562 + ], + "type": "text", + "content": "4.1. Results" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "text", + "content": "PASCAL-5" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "inline_equation", + "content": "^i" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "text", + "content": " [5]: Tab. 1 compares the results of the proposed method (MSI) with baseline models on PASCAL-5" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "inline_equation", + "content": "^i" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "text", + "content": ". MSI allowed almost all experiments to set a new SOTA record. We observed that VAT + MSI provided the most noticeable gains. In the 1-shot test, VAT + MSI provided a " + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "inline_equation", + "content": "3.0\\%" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "text", + "content": " gain with ResNet50 and a " + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "inline_equation", + "content": "2.5\\%" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "text", + "content": " gain with ResNet101. COCO-20" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "inline_equation", + "content": "^i" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "text", + "content": " [15]: Tab. 2 reports results on the COCO-20" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "inline_equation", + "content": "^i" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "text", + "content": " dataset. Our method delivered consistent improvement in almost all experiments. VAT + MSI provided a gain of " + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "inline_equation", + "content": "5.5\\%" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "text", + "content": " with ResNet50 [7] and " + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "inline_equation", + "content": "7.2\\%" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "text", + "content": " with ResNet101 [7] in mIoU in the 1-shot test, and delivered gains of " + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "inline_equation", + "content": "5.8\\%" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "inline_equation", + "content": "5.6\\%" + }, + { + "bbox": [ + 304, + 569, + 545, + 712 + ], + "type": "text", + "content": " in the 5-shot test." + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19270" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 97, + 70, + 496, + 300 + ], + "blocks": [ + { + "bbox": [ + 97, + 70, + 496, + 300 + ], + "lines": [ + { + "bbox": [ + 97, + 70, + 496, + 300 + ], + "spans": [ + { + "bbox": [ + 97, + 70, + 496, + 300 + ], + "type": "table", + "html": "
BackboneMethods1-shot5-shot
\\( 5^0 \\)\\( 5^1 \\)\\( 5^2 \\)\\( 5^3 \\)mIoUFB-IoU\\( 5^0 \\)\\( 5^1 \\)\\( 5^2 \\)\\( 5^3 \\)mIoUFB-IoU
ResNet50 [7]CWT [19]56.362.059.947.256.4-61.368.568.556.663.7-
RePRI [1]59.868.362.148.559.7-64.671.471.159.366.6-
CyCTR [36]67.872.858.058.064.2-71.173.260.557.565.6-
BAM [12]69.073.667.661.167.8-70.675.170.867.270.9-
DCAMA [29]67.572.359.659.064.676.770.373.267.467.169.580.6
HSNet [21]64.370.760.360.564.076.770.373.267.467.169.580.6
ASNet [11]68.971.761.162.766.177.772.674.365.367.170.880.4
VAT [8]67.671.262.360.165.377.472.473.668.665.770.080.9
HSNet + MSI68.171.558.262.965.276.570.772.861.566.667.978.2
ASNet + MSI69.271.759.764.466.377.972.073.264.068.069.380.2
VAT + MSI71.072.563.865.968.379.173.074.266.670.571.181.2
ResNet101 [7]CWT [19]56.965.261.248.858.0-62.670.268.857.264.7-
RePRI [1]59.668.662.247.259.4-66.271.467.057.765.6-
CyCTR [36]69.372.756.558.664.372.973.574.058.660.266.675.0
DCAMA [29]65.471.463.258.364.677.670.773.766.861.968.380.8
HSNet [21]67.372.362.063.166.277.671.874.467.068.370.480.6
ASNet [11]69.073.162.063.666.978.073.175.665.769.971.181.0
VAT [8]68.472.564.864.267.578.873.375.268.469.571.682.0
HSNet + MSI70.572.960.664.367.177.871.974.964.167.769.779.5
ASNet + MSI70.573.861.365.567.878.873.475.566.271.071.581.3
VAT + MSI73.173.964.768.870.182.373.676.168.071.372.282.3
", + "image_path": "24886588bd1a304049d62d67717f54418f0b6912386e9aff35f0f40bd8139a78.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 78, + 321, + 376, + 495 + ], + "blocks": [ + { + "bbox": [ + 149, + 300, + 443, + 312 + ], + "lines": [ + { + "bbox": [ + 149, + 300, + 443, + 312 + ], + "spans": [ + { + "bbox": [ + 149, + 300, + 443, + 312 + ], + "type": "text", + "content": "Table 1. Performance evaluation on Pascal-5 " + }, + { + "bbox": [ + 149, + 300, + 443, + 312 + ], + "type": "inline_equation", + "content": "{}^{i}" + }, + { + "bbox": [ + 149, + 300, + 443, + 312 + ], + "type": "text", + "content": " [5]. Best results are shown in bold." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 78, + 321, + 376, + 495 + ], + "lines": [ + { + "bbox": [ + 78, + 321, + 376, + 495 + ], + "spans": [ + { + "bbox": [ + 78, + 321, + 376, + 495 + ], + "type": "table", + "html": "
BackboneMethodsI-shot5-shot
200201202203mIoU200201202203mIoU
ResNet50 [7]RePRI [1]32.038.732.733.134.139.345.439.741.841.6
CyCTR [36]38.943.039.639.840.341.148.945.247.045.6
BAM [12]43.450.647.543.446.249.354.251.649.651.2
DCAMA [29]41.945.144.441.743.345.950.550.746.048.3
HSNet [21]36.343.138.738.739.243.351.348.245.046.9
ASNet [11]41.544.142.840.642.247.650.147.746.447.9
VAT [8]39.043.842.639.741.344.151.150.246.147.9
HSNet + MSI40.946.948.845.345.545.353.553.149.350.3
ASNet + MSI41.546.343.542.143.446.050.747.546.947.8
VAT + MSI42.449.249.446.146.847.154.954.151.952.0
ResNet101 [7]DCAMA [29]41.546.245.241.343.548.058.054.347.151.9
HSNet [21]37.244.142.441.341.245.953.051.847.149.5
ASNet [11]41.845.443.241.943.148.052.149.748.249.5
VAT [8]39.544.446.140.442.645.254.151.147.149.4
HSNet + MSI42.450.149.548.347.648.057.352.652.652.6
ASNet + MSI42.945.244.343.444.047.749.949.048.848.9
VAT + MSI44.854.252.348.049.849.358.056.152.754.0
", + "image_path": "2c4276d9b77b9b756ba59afe3df60e3f56194a9b567bab7a797b2fa10268e8f4.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 380, + 355, + 515, + 450 + ], + "blocks": [ + { + "bbox": [ + 380, + 355, + 515, + 450 + ], + "lines": [ + { + "bbox": [ + 380, + 355, + 515, + 450 + ], + "spans": [ + { + "bbox": [ + 380, + 355, + 515, + 450 + ], + "type": "table", + "html": "
BackboneMethodsmIoU
1-shot5-shot
ResNet50 [7]HSNet [21]85.587.8
VAT [8]89.590.3
HSNet + MSI87.588.4
VAT + MSI90.090.6
ResNet101 [7]HSNet [21]86.588.5
VAT [8]90.090.6
HSNet + MSI88.189.2
VAT + MSI90.691.0
", + "image_path": "d336867fbe8db5ccb5ba87461c6f5abb91dd82f701c676d37dc0084217f941d9.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_body" + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 104, + 524, + 230, + 612 + ], + "blocks": [ + { + "bbox": [ + 378, + 451, + 515, + 472 + ], + "lines": [ + { + "bbox": [ + 378, + 451, + 515, + 472 + ], + "spans": [ + { + "bbox": [ + 378, + 451, + 515, + 472 + ], + "type": "text", + "content": "Table 3. Performance evaluation on FSS-1000 [14]." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 79, + 496, + 378, + 506 + ], + "lines": [ + { + "bbox": [ + 79, + 496, + 378, + 506 + ], + "spans": [ + { + "bbox": [ + 79, + 496, + 378, + 506 + ], + "type": "text", + "content": "Table 2. Performance evaluation on COCO- " + }, + { + "bbox": [ + 79, + 496, + 378, + 506 + ], + "type": "inline_equation", + "content": "{20}^{i}" + }, + { + "bbox": [ + 79, + 496, + 378, + 506 + ], + "type": "text", + "content": " [15]. Best results are shown in bold." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 104, + 524, + 230, + 612 + ], + "lines": [ + { + "bbox": [ + 104, + 524, + 230, + 612 + ], + "spans": [ + { + "bbox": [ + 104, + 524, + 230, + 612 + ], + "type": "table", + "html": "
BackboneMethods1-shot mIoU5-shot mIoU
ResNet50 [7]HSNet [21]61.668.7
VAT [8]64.569.7
HSNet + MSI66.070.8
VAT + MSI67.872.6
ResNet101 [7]HSNet [21]64.170.3
VAT [8]66.871.4
HSNet + MSI67.372.3
VAT + MSI69.274.1
", + "image_path": "51fbb63bf1042ddfaef9f0b19f06f47964aa7fbc56b1c3d017a666b66ec62aae.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 612, + 287, + 643 + ], + "lines": [ + { + "bbox": [ + 47, + 612, + 287, + 643 + ], + "spans": [ + { + "bbox": [ + 47, + 612, + 287, + 643 + ], + "type": "text", + "content": "Table 4. Generalizability performance evaluation on PASCAL-5" + }, + { + "bbox": [ + 47, + 612, + 287, + 643 + ], + "type": "inline_equation", + "content": "^i" + }, + { + "bbox": [ + 47, + 612, + 287, + 643 + ], + "type": "text", + "content": " [5] after training with COCO-20" + }, + { + "bbox": [ + 47, + 612, + 287, + 643 + ], + "type": "inline_equation", + "content": "^i" + }, + { + "bbox": [ + 47, + 612, + 287, + 643 + ], + "type": "text", + "content": " [15]. Best results are shown in bold." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 47, + 665, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 665, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 665, + 288, + 715 + ], + "type": "text", + "content": "FSS-1000 [14]: Tab. 3 compares the performance of our MSI on FSS-1000 using two baselines: HSNet [21] and VAT [8]. HSNet + MSI delivered " + }, + { + "bbox": [ + 47, + 665, + 288, + 715 + ], + "type": "inline_equation", + "content": "2.0\\%" + }, + { + "bbox": [ + 47, + 665, + 288, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 665, + 288, + 715 + ], + "type": "inline_equation", + "content": "0.6\\%" + }, + { + "bbox": [ + 47, + 665, + 288, + 715 + ], + "type": "text", + "content": " mIoU improvements on 1-shot and 5-shot tests, respectively, with" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "spans": [ + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "text", + "content": "ResNet50 [7]. HSNet + MSI with ResNet101 [7] showed " + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "inline_equation", + "content": "1.6\\%" + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "inline_equation", + "content": "0.7\\%" + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "text", + "content": " gains in mIoU. VAT + MSI showed gains of " + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "inline_equation", + "content": "0.5\\%" + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "inline_equation", + "content": "0.3\\%" + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "text", + "content": " in mIoU with ResNet50 [7] and gains of " + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "inline_equation", + "content": "0.3\\%" + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "inline_equation", + "content": "0.2\\%" + }, + { + "bbox": [ + 306, + 525, + 545, + 574 + ], + "type": "text", + "content": " in mIoU with ResNet101 [7]." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 578, + 547, + 662 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 578, + 547, + 662 + ], + "spans": [ + { + "bbox": [ + 305, + 578, + 547, + 662 + ], + "type": "text", + "content": "Generalization Test: We tested the generalizability of trained models in Tab. 4. HSNet [21] and VAT [8] were compared with HSNet + MSI and VAT + MSI, respectively. Both HSNet + MSI and VAT + MSI delivered significant mIoU gains on 1-shot and 5-shot tests. HSNet + MSI with ResNet50 [7] provided " + }, + { + "bbox": [ + 305, + 578, + 547, + 662 + ], + "type": "inline_equation", + "content": "4.4\\%" + }, + { + "bbox": [ + 305, + 578, + 547, + 662 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 578, + 547, + 662 + ], + "type": "inline_equation", + "content": "2.1\\%" + }, + { + "bbox": [ + 305, + 578, + 547, + 662 + ], + "type": "text", + "content": " improvements and VAT + MSI showed " + }, + { + "bbox": [ + 305, + 578, + 547, + 662 + ], + "type": "inline_equation", + "content": "3.4\\%" + }, + { + "bbox": [ + 305, + 578, + 547, + 662 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 578, + 547, + 662 + ], + "type": "inline_equation", + "content": "2.7\\%" + }, + { + "bbox": [ + 305, + 578, + 547, + 662 + ], + "type": "text", + "content": " gains." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 665, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 665, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 305, + 665, + 547, + 715 + ], + "type": "text", + "content": "Qualitative Results: According to the visual comparison, MSI allows VAT to capture, detailed, accurate, and complete object information, and thus lead to an improved performance and avoid segmenting the wrong object (Fig. 4)." + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19271" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 70, + 287, + 145 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 287, + 145 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 287, + 145 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 287, + 145 + ], + "type": "table", + "html": "
Method & BackboneFMSTFSIFmIoUFB-IoU
VAT (ResNet50)✓60.772.0
✓65.3 (Baseline [8])77.4
✓65.277.4
✓✓66.3 (HM [22])78.0
✓✓68.3 (Ours)79.1
✓✓65.777.5
✓✓✓67.178.8
", + "image_path": "3e3cf6c30f810bfc6bcc8d1c00a57e388a986f359b6033656043c6779f6e257e.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 50, + 210, + 284, + 275 + ], + "blocks": [ + { + "bbox": [ + 47, + 145, + 287, + 189 + ], + "lines": [ + { + "bbox": [ + 47, + 145, + 287, + 189 + ], + "spans": [ + { + "bbox": [ + 47, + 145, + 287, + 189 + ], + "type": "text", + "content": "Table 5. Ablation study of the different combination of features with VAT [8] (ResNet50 [7]) on PASCAL-5" + }, + { + "bbox": [ + 47, + 145, + 287, + 189 + ], + "type": "inline_equation", + "content": "^i" + }, + { + "bbox": [ + 47, + 145, + 287, + 189 + ], + "type": "text", + "content": " [5]). " + }, + { + "bbox": [ + 47, + 145, + 287, + 189 + ], + "type": "inline_equation", + "content": "\\checkmark" + }, + { + "bbox": [ + 47, + 145, + 287, + 189 + ], + "type": "text", + "content": " denotes that these features are utilized to generate super correlation maps (SCM). The best results are shown in bold." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 210, + 284, + 275 + ], + "lines": [ + { + "bbox": [ + 50, + 210, + 284, + 275 + ], + "spans": [ + { + "bbox": [ + 50, + 210, + 284, + 275 + ], + "type": "table", + "html": "
BackboneMethods1-shot
200201202203mIoU
ResNet50 [7]VAT [8] (Baseline)67.671.262.360.165.3
VAT+MSI (Feature Add.)68.571.060.862.065.6
VAT+MSI (Correlation Add.)67.068.253.556.061.2
VAT+MSI (Attention)69.972.563.463.867.4
VAT+MSI (Ours)71.072.563.865.968.3
", + "image_path": "20376b7e1c3018bfca963d71878252d9caef7cb3fdcfe865e5d642f3f8b7523a.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 51, + 318, + 284, + 382 + ], + "blocks": [ + { + "bbox": [ + 47, + 275, + 286, + 297 + ], + "lines": [ + { + "bbox": [ + 47, + 275, + 286, + 297 + ], + "spans": [ + { + "bbox": [ + 47, + 275, + 286, + 297 + ], + "type": "text", + "content": "Table 6. Different methods of generating super correlation maps (SCM) on PASCAL- " + }, + { + "bbox": [ + 47, + 275, + 286, + 297 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 47, + 275, + 286, + 297 + ], + "type": "text", + "content": " [5]. Best results are shown in bold." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 51, + 318, + 284, + 382 + ], + "lines": [ + { + "bbox": [ + 51, + 318, + 284, + 382 + ], + "spans": [ + { + "bbox": [ + 51, + 318, + 284, + 382 + ], + "type": "table", + "html": "
BackboneMethods1-shot
200201202203mIoU
ResNet50 (PASCAL-5i)VAT [8]59.942.442.045.547.5
VAT + MSI68.146.643.647.151.4
ResNet50 (COCO-20i)VAT [8]29.732.436.029.031.8
VAT + MSI30.737.940.933.935.9
", + "image_path": "1a3a143036887b48fb82a1e15106b9eab9842699d5de5600114435303ba25ae3.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 51, + 438, + 284, + 492 + ], + "blocks": [ + { + "bbox": [ + 47, + 383, + 287, + 416 + ], + "lines": [ + { + "bbox": [ + 47, + 383, + 287, + 416 + ], + "spans": [ + { + "bbox": [ + 47, + 383, + 287, + 416 + ], + "type": "text", + "content": "Table 7. Performance comparison on PASCAL- " + }, + { + "bbox": [ + 47, + 383, + 287, + 416 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 47, + 383, + 287, + 416 + ], + "type": "text", + "content": " [5] and COCO" + }, + { + "bbox": [ + 47, + 383, + 287, + 416 + ], + "type": "inline_equation", + "content": "20^{i}" + }, + { + "bbox": [ + 47, + 383, + 287, + 416 + ], + "type": "text", + "content": " [15] for cases where support masks occupy below " + }, + { + "bbox": [ + 47, + 383, + 287, + 416 + ], + "type": "inline_equation", + "content": "5\\%" + }, + { + "bbox": [ + 47, + 383, + 287, + 416 + ], + "type": "text", + "content": " of the support images. Best results are shown in bold." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 51, + 438, + 284, + 492 + ], + "lines": [ + { + "bbox": [ + 51, + 438, + 284, + 492 + ], + "spans": [ + { + "bbox": [ + 51, + 438, + 284, + 492 + ], + "type": "table", + "html": "
BackboneMethods1-shot
200201202203mIoU
ResNet50 [7]VAT (w/o person in BG)67.770.961.361.665.2
VAT (w/ person in BG)67.671.262.360.165.3
VAT + MSI (w/o person in BG)69.471.460.564.166.3
VAT + MSI (w/ person in BG)71.072.563.865.968.3
", + "image_path": "63fe19040c47858ce93d850e15ede334fbbee0874301367a6d50bc7e5945bcef.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 492, + 286, + 514 + ], + "lines": [ + { + "bbox": [ + 47, + 492, + 286, + 514 + ], + "spans": [ + { + "bbox": [ + 47, + 492, + 286, + 514 + ], + "type": "text", + "content": "Table 8. Training VAT + MSI on PASCAL-5i[5] without the person class existing as background of the support image." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 545, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 545, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 545, + 287, + 713 + ], + "type": "text", + "content": "Small improvement with ASNet/HSNet: Performance drop in 5-shot is observed on PASCAL with HSNet and ASNet. There could be two reasons. First, both HSNet and ASNet models are limited in fully harnessing MSI's potential. Particularly, ASNet downsamples support features by pooling which loses target information and hence limits the capability of both support target features (STF) and support image features (SIF) in MSI. HSNet lacks self-attention, which would aid MSI by facilitating the network in finding target information from the entire SIF by leveraging STF. Second, ASNet, HSNet, VAT, and their MSI-empowered counterparts are trained for the one-shot setting, which might prevent MSI from specializing in 5-shot testing (Tab 1)." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 72, + 425, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 425, + 83 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 425, + 83 + ], + "type": "text", + "content": "4.2. When is MSI useful?" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 90, + 545, + 317 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 90, + 545, + 317 + ], + "spans": [ + { + "bbox": [ + 304, + 90, + 545, + 317 + ], + "type": "text", + "content": "As MSI can better capture target object information, it is more capable of handling challenging FSS scenarios. Fig. 1 draws visual comparisons between " + }, + { + "bbox": [ + 304, + 90, + 545, + 317 + ], + "type": "inline_equation", + "content": "\\mathrm{VAT} + \\mathrm{MSI}" + }, + { + "bbox": [ + 304, + 90, + 545, + 317 + ], + "type": "text", + "content": " and the baseline VAT [8] on four challenging FSS cases where MSI is particularly effective. We discuss these cases below. When an instance of the target class is not masked: Fig. 5 visualizes different kinds of features in SIF using " + }, + { + "bbox": [ + 304, + 90, + 545, + 317 + ], + "type": "inline_equation", + "content": "\\mathrm{VAT} + \\mathrm{MSI}" + }, + { + "bbox": [ + 304, + 90, + 545, + 317 + ], + "type": "text", + "content": " on PASCAL- " + }, + { + "bbox": [ + 304, + 90, + 545, + 317 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 304, + 90, + 545, + 317 + ], + "type": "text", + "content": " [5] (ResNet50 [7]). We observe that the support mask fails to mask an instance of the same class, i.e., the sofa on the right side. Therefore, SIF with target features is generated only from the upper sofa. Next, SIF with background features is not very effective overall, even though they better segment the magnified part in the cyan box. Finally, SIF with the entire image's features (ours), which incorporate both the former and the latter features, allows accurate segmentation of the target object, both inside and outside the cyan box. This indicates that background features have target information and utilizing the features improves the performance of FSS." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "spans": [ + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "text", + "content": "Support mask is very small: In PASCAL-5 and COCO-20, there are several cases where the support masks are very small because the target object only occupies a small part of the support image. We compare the mIoU for cases when the support mask occupies less than " + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "inline_equation", + "content": "5\\%" + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "text", + "content": " of the support image (Tab. 7). Compared to VAT [8], VAT + MSI displays noticeable gains of " + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "inline_equation", + "content": "3.9\\%" + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "inline_equation", + "content": "4.1\\%" + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "text", + "content": " (in mIOU) for PASCAL- " + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "inline_equation", + "content": "\\mathrm{COCO - }20^{i}" + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "text", + "content": ", respectively. These results show that MSI is more effective than the existing methods on very small target objects in both PASCAL- " + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "text", + "content": " [5] and COCO- " + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "inline_equation", + "content": "20^{i}" + }, + { + "bbox": [ + 304, + 318, + 546, + 437 + ], + "type": "text", + "content": " [15]." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 438, + 545, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 438, + 545, + 533 + ], + "spans": [ + { + "bbox": [ + 304, + 438, + 545, + 533 + ], + "type": "text", + "content": "Support mask is missing some of the target boundary: We observe that in PASCAL- " + }, + { + "bbox": [ + 304, + 438, + 545, + 533 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 304, + 438, + 545, + 533 + ], + "type": "text", + "content": " [5], COCO- " + }, + { + "bbox": [ + 304, + 438, + 545, + 533 + ], + "type": "inline_equation", + "content": "20^{i}" + }, + { + "bbox": [ + 304, + 438, + 545, + 533 + ], + "type": "text", + "content": " [15], and even FSS-1000 [14], the masks around boundaries can be imperfect (Fig. 6). By masking the features with an inaccurate mask, the boundary information of the target disappears inadvertently (Fig. 6). Therefore, compared to ours, previous methods face difficulties in finding the target in the query image with only limited target information." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 534, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 534, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 534, + 546, + 713 + ], + "type": "text", + "content": "When some background is helpful: In some FSS cases, the background offers relevant context that is unavailable in the support mask, for accurate segmentation. However, many recent methods depend on support masks to completely remove the background. We notice the person class frequently exists in the background of the support image in PASCAL- " + }, + { + "bbox": [ + 304, + 534, + 546, + 713 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 304, + 534, + 546, + 713 + ], + "type": "text", + "content": " [5]. Therefore, in order to empirically validate the importance of leveraging relevant background information, we train VAT+MSI and VAT [8] by removing the segmentation mask of the person class when the person exists in the background of the support image. We compare with or without the person class existing in the background of the support image in Tab. 8 and Fig. 7. After excluding the person class, the performance drop for VAT+MSI was much larger than VAT [8]." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19272" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 82, + 70, + 514, + 266 + ], + "blocks": [ + { + "bbox": [ + 82, + 70, + 514, + 266 + ], + "lines": [ + { + "bbox": [ + 82, + 70, + 514, + 266 + ], + "spans": [ + { + "bbox": [ + 82, + 70, + 514, + 266 + ], + "type": "image", + "image_path": "64eb3229b25a70a9bbc2b302fefdfbdd2c0534c446e0562fe160e23900e35cbd.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 84, + 270, + 504, + 281 + ], + "lines": [ + { + "bbox": [ + 84, + 270, + 504, + 281 + ], + "spans": [ + { + "bbox": [ + 84, + 270, + 504, + 281 + ], + "type": "text", + "content": "Figure 4. Visual comparison of VAT [8] and " + }, + { + "bbox": [ + 84, + 270, + 504, + 281 + ], + "type": "inline_equation", + "content": "\\mathrm{VAT} + \\mathrm{MSI}" + }, + { + "bbox": [ + 84, + 270, + 504, + 281 + ], + "type": "text", + "content": " with ResNet50 [7] on PASCAL- " + }, + { + "bbox": [ + 84, + 270, + 504, + 281 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 84, + 270, + 504, + 281 + ], + "type": "text", + "content": " [5] and COCO- " + }, + { + "bbox": [ + 84, + 270, + 504, + 281 + ], + "type": "inline_equation", + "content": "20^{i}" + }, + { + "bbox": [ + 84, + 270, + 504, + 281 + ], + "type": "text", + "content": " [15]." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 51, + 301, + 285, + 346 + ], + "blocks": [ + { + "bbox": [ + 51, + 301, + 285, + 346 + ], + "lines": [ + { + "bbox": [ + 51, + 301, + 285, + 346 + ], + "spans": [ + { + "bbox": [ + 51, + 301, + 285, + 346 + ], + "type": "image", + "image_path": "3ded2caf7e53ad40f6950aab7234a4669594e64ab86659944fd55857c2a22e3b.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 349, + 287, + 392 + ], + "lines": [ + { + "bbox": [ + 47, + 349, + 287, + 392 + ], + "spans": [ + { + "bbox": [ + 47, + 349, + 287, + 392 + ], + "type": "text", + "content": "Figure 5. Comparison of " + }, + { + "bbox": [ + 47, + 349, + 287, + 392 + ], + "type": "inline_equation", + "content": "\\mathrm{VAT} + \\mathrm{MSI}" + }, + { + "bbox": [ + 47, + 349, + 287, + 392 + ], + "type": "text", + "content": " on PASCAL- " + }, + { + "bbox": [ + 47, + 349, + 287, + 392 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 47, + 349, + 287, + 392 + ], + "type": "text", + "content": " [5] with ResNet50 [7] using different kinds of features in SIF: SIF with only target features, SIF with only background features, and SIF with the entire image's features." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 50, + 404, + 285, + 463 + ], + "blocks": [ + { + "bbox": [ + 50, + 404, + 285, + 463 + ], + "lines": [ + { + "bbox": [ + 50, + 404, + 285, + 463 + ], + "spans": [ + { + "bbox": [ + 50, + 404, + 285, + 463 + ], + "type": "image", + "image_path": "3d8b79a81369c5f09c510e00aa14d70d7388d2bc50a9373fb7a9f15e46f34154.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 465, + 287, + 488 + ], + "lines": [ + { + "bbox": [ + 47, + 465, + 287, + 488 + ], + "spans": [ + { + "bbox": [ + 47, + 465, + 287, + 488 + ], + "type": "text", + "content": "Figure 6. Missing information around boundary on PASCAL- " + }, + { + "bbox": [ + 47, + 465, + 287, + 488 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 47, + 465, + 287, + 488 + ], + "type": "text", + "content": " [5]. The mask is not perfect to cover entire target object." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 48, + 502, + 286, + 557 + ], + "blocks": [ + { + "bbox": [ + 48, + 502, + 286, + 557 + ], + "lines": [ + { + "bbox": [ + 48, + 502, + 286, + 557 + ], + "spans": [ + { + "bbox": [ + 48, + 502, + 286, + 557 + ], + "type": "image", + "image_path": "e4e847e66faeb0f675bf271531502790a73088f858dceb8dce241717e69241ed.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 559, + 287, + 615 + ], + "lines": [ + { + "bbox": [ + 47, + 559, + 287, + 615 + ], + "spans": [ + { + "bbox": [ + 47, + 559, + 287, + 615 + ], + "type": "text", + "content": "Figure 7. Comparison of performance when background information of support set is relevant to the background in the query image. Note that the person is in the background of the support image (target object is the ball). VAT failed to segment the ball correctly, while " + }, + { + "bbox": [ + 47, + 559, + 287, + 615 + ], + "type": "inline_equation", + "content": "\\mathrm{VAT} + \\mathrm{MSI}" + }, + { + "bbox": [ + 47, + 559, + 287, + 615 + ], + "type": "text", + "content": " was able to differentiate the ball and people." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 635, + 204, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 635, + 204, + 647 + ], + "spans": [ + { + "bbox": [ + 47, + 635, + 204, + 647 + ], + "type": "text", + "content": "4.3. Ablation Study and Analysis" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "type": "text", + "content": "Why the masked support image is helpful: (1) Feature masking (FM) is utilized by several existing FSS models [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12], obtained by masking background features. The target features in FM are not merely targeted object features. When extracting target" + } + ] + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 311, + 301, + 539, + 405 + ], + "blocks": [ + { + "bbox": [ + 311, + 301, + 539, + 405 + ], + "lines": [ + { + "bbox": [ + 311, + 301, + 539, + 405 + ], + "spans": [ + { + "bbox": [ + 311, + 301, + 539, + 405 + ], + "type": "image", + "image_path": "b8eb9b5cec82d4913a32029aa8017c1e468dcbd1ac248beaf9ce45469dd56077.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 408, + 545, + 473 + ], + "lines": [ + { + "bbox": [ + 305, + 408, + 545, + 473 + ], + "spans": [ + { + "bbox": [ + 305, + 408, + 545, + 473 + ], + "type": "text", + "content": "Figure 8. Feature map comparison between support target features (STF) and feature masking (FM). The cyan circles show that STF captures more fine-grained features near the target object boundary, however, FM struggles to capture the same. In deeper layers, the advantage of STF becomes more apparent (e.g. Block 3)." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 309, + 476, + 544, + 537 + ], + "blocks": [ + { + "bbox": [ + 309, + 476, + 544, + 537 + ], + "lines": [ + { + "bbox": [ + 309, + 476, + 544, + 537 + ], + "spans": [ + { + "bbox": [ + 309, + 476, + 544, + 537 + ], + "type": "image", + "image_path": "e90bfa14d07590230f039259dc5abde5aeef00baeaab615ba84a3159f4a09c06.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 539, + 545, + 594 + ], + "lines": [ + { + "bbox": [ + 305, + 539, + 545, + 594 + ], + "spans": [ + { + "bbox": [ + 305, + 539, + 545, + 594 + ], + "type": "text", + "content": "Figure 9. Feature masking (FM) overlooks the impact of the growing receptive field. Background deep features could contain target object information. FM thus loses the detailed target information by masking all features using a support mask. This becomes severe when the support mask is small/inaccurate." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 605, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 546, + 713 + ], + "type": "text", + "content": "features in FM, the features corresponding to background objects could also be present because of the enlarging receptive fields [20]. These background features interfere with obtaining target information. However, this interference can be eliminated by masking the background at the input image level in our MSI. (2) STF holds more target features such as the texture and boundary of the target object than FM. In contrast, FM loses such information by masking features to remove the background (Fig. 8) [22]." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19273" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "type": "text", + "content": "How MSI helps for each case: FM is utilized in most FSS works to remove the background in support features [34, 33, 31, 23, 35]. (a) When the support mask fails to mask the same target class in a different location, unlike FM, SIF in MSI can still retain the target information (Fig. 5). (b) When the target class is minuscule, FM features retain minimal target information from masking downstream features (Fig. 9). However, in MSI, we mask support images at the input level. As such, we can retain fine-grained information in STF. Also, SIF could hold the target information missed by STF due to a small mask (Tab. 8). (c) FM loses target boundary information (Fig. 6) when removing background features with an inaccurate mask. However, MSI can overcome this by exploiting additional target information in SIF and it facilitates a network in recovering fine-grained target details through the encoder/decoder. (d) FM cannot utilize the contextual features from the background. For example, if the support and query images have the same non-target object in the background, MSI uses " + }, + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "type": "inline_equation", + "content": "CS_{1}" + }, + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "type": "text", + "content": " to learn contextual features and recognizes the same objects in QF and SIF, and " + }, + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "type": "inline_equation", + "content": "CS_{2}" + }, + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "type": "text", + "content": " to find the similarity between STF and QF to learn target-specific features to locate the target object (Fig. 3, Eq. 3). Both " + }, + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "type": "inline_equation", + "content": "CS_{1}" + }, + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "type": "inline_equation", + "content": "CS_{2}" + }, + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "type": "text", + "content": " allow the network to recognize non-targets (Fig. 7, Tab. 8) and leverage such information." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 373, + 287, + 469 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 373, + 287, + 469 + ], + "spans": [ + { + "bbox": [ + 46, + 373, + 287, + 469 + ], + "type": "text", + "content": "Best features for SCM: In Tab. 5, we show results when using various combinations of features to obtain SCM. For this purpose, VAT [8] with ResNet50 backbone is used as a baseline and PASCAL- " + }, + { + "bbox": [ + 46, + 373, + 287, + 469 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 46, + 373, + 287, + 469 + ], + "type": "text", + "content": " is chosen for training and testing the model. The ablation study reveals that harnessing both SIF and STF via concatenation achieves the best mIoU. Please see the supplementary text for visualizations of the correlation value distributions for SIF and STF." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 472, + 289, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 472, + 289, + 628 + ], + "spans": [ + { + "bbox": [ + 46, + 472, + 289, + 628 + ], + "type": "text", + "content": "On different ways of fusing SIF and STF: The proposed method, MSI, calculates cosine similarity between " + }, + { + "bbox": [ + 46, + 472, + 289, + 628 + ], + "type": "inline_equation", + "content": "\\langle" + }, + { + "bbox": [ + 46, + 472, + 289, + 628 + ], + "type": "text", + "content": "STF, QF " + }, + { + "bbox": [ + 46, + 472, + 289, + 628 + ], + "type": "inline_equation", + "content": "\\rangle" + }, + { + "bbox": [ + 46, + 472, + 289, + 628 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 472, + 289, + 628 + ], + "type": "inline_equation", + "content": "\\langle" + }, + { + "bbox": [ + 46, + 472, + 289, + 628 + ], + "type": "text", + "content": "SIF, QF " + }, + { + "bbox": [ + 46, + 472, + 289, + 628 + ], + "type": "inline_equation", + "content": "\\rangle" + }, + { + "bbox": [ + 46, + 472, + 289, + 628 + ], + "type": "text", + "content": ", and concatenates the two generated correlation maps. To see the effectiveness of this method, we experimented with different approaches to fuse SIF and STF to obtain SCM (see Tab. 6). Feature addition refers to the element-wise addition of features before calculating the cosine similarity to get the correlation map. Correlation addition means simply adding two correlation maps elementwise. The attention method merges two correlation maps through 1x1 depth-wise attention based on Attention U-Net [24]. Among all design choices for fusion, concatenating the two correlation maps showed the best performance." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": "Fast training convergence: We notice that MSI with VAT [8] and ResNet50 on PASCAL- " + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\mathrm{VAT} + \\mathrm{MSI}" + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": ", provides 3.3x faster convergence (i.e. to reach mIoU of " + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "inline_equation", + "content": "60\\%" + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": ") on average than VAT (Fig. 10), along with a remarkable improvement in performance. Similarly with HSNet, HSNet+MSI allows faster convergence by 4.5x on average. See supplementary for plots." + } + ] + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 314, + 72, + 541, + 164 + ], + "blocks": [ + { + "bbox": [ + 314, + 72, + 541, + 164 + ], + "lines": [ + { + "bbox": [ + 314, + 72, + 541, + 164 + ], + "spans": [ + { + "bbox": [ + 314, + 72, + 541, + 164 + ], + "type": "image", + "image_path": "765c17047fb3bbd89bc616a4bf99967ed550a72caf145878b744cc7a14aefec4.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "lines": [ + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "spans": [ + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "text", + "content": "Figure 10. Train. and val. profiles of VAT [8] and " + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "inline_equation", + "content": "\\mathrm{VAT} + \\mathrm{MSI}" + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "text", + "content": " on PASCAL- " + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "inline_equation", + "content": "5^{i}" + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "text", + "content": " with ResNet50. " + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "inline_equation", + "content": "\\mathrm{VAT} + \\mathrm{MSI}" + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "text", + "content": " provides " + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "inline_equation", + "content": "3.3\\mathrm{x}" + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "text", + "content": " faster convergence (to reach " + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "inline_equation", + "content": "60\\%" + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "text", + "content": " in mIoU) on average than VAT. Red circles indicate when the training accuracy reaches " + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "inline_equation", + "content": "60\\%" + }, + { + "bbox": [ + 304, + 167, + 547, + 212 + ], + "type": "text", + "content": " in mIoU." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 306, + 231, + 379, + 243 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 231, + 379, + 243 + ], + "spans": [ + { + "bbox": [ + 306, + 231, + 379, + 243 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 251, + 547, + 360 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 251, + 547, + 360 + ], + "spans": [ + { + "bbox": [ + 304, + 251, + 547, + 360 + ], + "type": "text", + "content": "We proposed a new method, MSI, maximizing the information of the support set, deviating from the masking method [37] widely used in many FSS models [34, 33, 31, 23, 35, 13, 36, 21, 9, 11, 12]. The joint exploitation of SIF and STF develops a synergy between them, which allows handling several challenging FSS cases. The results show significant performance improvements across all benchmarks on recent, strong FSS baselines (HSNet [21], ASNet [11], and VAT [8])." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 370, + 399, + 384 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 370, + 399, + 384 + ], + "spans": [ + { + "bbox": [ + 306, + 370, + 399, + 384 + ], + "type": "text", + "content": "Acknowledgment" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 390, + 545, + 414 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 390, + 545, + 414 + ], + "spans": [ + { + "bbox": [ + 306, + 390, + 545, + 414 + ], + "type": "text", + "content": "This work is supported in part by NSF Grant #1955404 and #1955365." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 426, + 365, + 437 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 426, + 365, + 437 + ], + "spans": [ + { + "bbox": [ + 306, + 426, + 365, + 437 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 310, + 445, + 547, + 714 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 310, + 445, + 547, + 512 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 445, + 547, + 512 + ], + "spans": [ + { + "bbox": [ + 310, + 445, + 547, + 512 + ], + "type": "text", + "content": "[1] Malik Boudiaf, Hoel Kervadec, Ziko Imtiaz Masud, Pablo Piantanida, Ismail Ben Ayed, and Jose Dolz. Few-Shot Segmentation Without Meta-Learning: A Good Transductive Inference Is All You Need? In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 13979-13988, June 2021. 6" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 311, + 513, + 547, + 578 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 513, + 547, + 578 + ], + "spans": [ + { + "bbox": [ + 311, + 513, + 547, + 578 + ], + "type": "text", + "content": "[2] Liang-Chieh Chen, George Papandreou, Iasonas Kokkinos, Kevin Murphy, and Alan L. Yuille. DeepLab: Semantic Image Segmentation with Deep Convolutional Nets, Atrous Convolution, and Fully Connected CRFs. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 40(4):834-848, 2018. 1" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 311, + 580, + 547, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 580, + 547, + 634 + ], + "spans": [ + { + "bbox": [ + 311, + 580, + 547, + 634 + ], + "type": "text", + "content": "[3] Seokju Cho, Sunghwan Hong, Sangryul Jeon, Yunsung Lee, Kwanghoon Sohn, and Seungryong Kim. CATs: Cost Aggregation Transformers for Visual Correspondence. In Proceedings of Advances in Neural Information Processing Systems (NeurIPS), 2021. 5" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 311, + 635, + 547, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 635, + 547, + 689 + ], + "spans": [ + { + "bbox": [ + 311, + 635, + 547, + 689 + ], + "type": "text", + "content": "[4] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. ImageNet: A large-scale hierarchical image database. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 248–255, 2009. 3, 5" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 311, + 691, + 547, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 691, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 311, + 691, + 547, + 714 + ], + "type": "text", + "content": "[5] Mark Everingham, Luc Van Gool, Christopher Williams, John Winn, and Andrew Zisserman. The Pascal Visual Ob-" + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19274" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 712 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "type": "text", + "content": "ject Classes (VOC) challenge. International Journal of Computer Vision (IJCV), 88:303-338, 06 2010. 1, 2, 5, 6, 7, 8" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 53, + 96, + 288, + 163 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 96, + 288, + 163 + ], + "spans": [ + { + "bbox": [ + 53, + 96, + 288, + 163 + ], + "type": "text", + "content": "[6] Xavier Glorot, Antoine Bordes, and Yoshua Bengio. Deep Sparse Rectifier Neural Networks. In Proceedings of the Fourteenth International Conference on Artificial Intelligence and Statistics (AISTAT), volume 15 of Proceedings of Machine Learning Research (PMLR), pages 315-323, Fort Lauderdale, FL, USA, 11-13 Apr 2011. 5" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 164, + 288, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 164, + 288, + 217 + ], + "spans": [ + { + "bbox": [ + 53, + 164, + 288, + 217 + ], + "type": "text", + "content": "[7] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep Residual Learning for Image Recognition. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 770-778, 2016. 3, 5, 6, 7, 8" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 220, + 288, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 220, + 288, + 262 + ], + "spans": [ + { + "bbox": [ + 53, + 220, + 288, + 262 + ], + "type": "text", + "content": "[8] Sunghwan Hong, Seokju Cho, Jisu Nam, and Seungryong Kim. Cost Aggregation Is All You Need for Few-Shot Segmentation. arXiv preprint arXiv:2112.11685, 2021. 2, 3, 5, 6, 7, 8, 9" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 264, + 288, + 319 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 264, + 288, + 319 + ], + "spans": [ + { + "bbox": [ + 53, + 264, + 288, + 319 + ], + "type": "text", + "content": "[9] Sunghwan Hong, Seokju Cho, Jisu Nam, Stephen Lin, and Seungryong Kim. Cost Aggregation with 4D Convolutional Swin Transformer for Few-Shot Segmentation. In Proceedings of European Conference on Computer Vision (ECCV), 2022. 1, 2, 3, 4, 5, 8, 9" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 321, + 287, + 376 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 321, + 287, + 376 + ], + "spans": [ + { + "bbox": [ + 48, + 321, + 287, + 376 + ], + "type": "text", + "content": "[10] M. Amirul Islam, M. Kowal, S. Jia, K. G. Derpanis, and N. B. Bruce. Global Pooling, More than Meets the Eye: Position Information is Encoded Channel-Wise in CNNs. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 773-781, 2021. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 378, + 287, + 421 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 378, + 287, + 421 + ], + "spans": [ + { + "bbox": [ + 48, + 378, + 287, + 421 + ], + "type": "text", + "content": "[11] Dahiyun Kang and Minsu Cho. Integrative Few-Shot Learning for Classification and Segmentation. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 1, 2, 3, 4, 5, 6, 8, 9" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 422, + 287, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 422, + 287, + 487 + ], + "spans": [ + { + "bbox": [ + 48, + 422, + 287, + 487 + ], + "type": "text", + "content": "[12] C. Lang, G. Cheng, B. Tu, and J. Han. Learning what not to segment: A new perspective on few-shot segmentation. In 2022 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 8047-8057, Los Alamitos, CA, USA, jun 2022. IEEE Computer Society. 1, 2, 3, 4, 6, 8, 9" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 489, + 287, + 544 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 489, + 287, + 544 + ], + "spans": [ + { + "bbox": [ + 48, + 489, + 287, + 544 + ], + "type": "text", + "content": "[13] Gen Li, Varun Jampani, Laura Sevilla-Lara, Deqing Sun, Jonghyun Kim, and Joongkyu Kim. Adaptive Prototype Learning and Allocation for Few-Shot Segmentation. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2021. 1, 2, 3, 4, 5, 8, 9" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 545, + 287, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 545, + 287, + 600 + ], + "spans": [ + { + "bbox": [ + 48, + 545, + 287, + 600 + ], + "type": "text", + "content": "[14] Xiang Li, Tianhan Wei, Yau Pun Chen, Yu-Wing Tai, and Chi-Keung Tang. FSS-1000: A 1000-Class Dataset for Few-Shot Segmentation. Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2020. 2, 5, 6, 7" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 602, + 287, + 667 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 602, + 287, + 667 + ], + "spans": [ + { + "bbox": [ + 48, + 602, + 287, + 667 + ], + "type": "text", + "content": "[15] Tsung-Yi Lin, Michael Maire, Serge Belongie, Lubomir Bourdev, Ross Girshick, James Hays, Pietro Perona, Deva Ramanan, C. Lawrence Zitnick, and Piotr Dólar. Microsoft COCO: Common Objects in Context. In Proceedings of European Conference on Computer Vision (ECCV), 2014. 1, 2, 5, 6, 7, 8" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 669, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 669, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 669, + 287, + 712 + ], + "type": "text", + "content": "[16] Weide Liu, Chi Zhang, Henghui Ding, Tzu-Yi Hung, and Guosheng Lin. Few-shot Segmentation with Optimal Transport Matching and Message Flow. IEEE Transactions on Multimedia (TMM), 2022. 1, 2, 4, 5" + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 714 + ], + "type": "list", + "angle": 0, + "index": 25, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 128 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 128 + ], + "type": "text", + "content": "[17] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin Transformer: Hierarchical Vision Transformer using Shifted Windows. In Proceedings of International Conference on Computer Vision (ICCV), 2021. 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 307, + 129, + 545, + 185 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 129, + 545, + 185 + ], + "spans": [ + { + "bbox": [ + 307, + 129, + 545, + 185 + ], + "type": "text", + "content": "[18] J. Long, E. Shelhamer, and T. Darrell. Fully convolutional networks for semantic segmentation. In 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 3431-3440, Los Alamitos, CA, USA, jun 2015. IEEE Computer Society. 1" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 308, + 186, + 547, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 186, + 547, + 239 + ], + "spans": [ + { + "bbox": [ + 308, + 186, + 547, + 239 + ], + "type": "text", + "content": "[19] Zhihe Lu, Sen He, Xiatian Zhu, Li Zhang, Yi-Zhe Song, and Tao Xiang. Simpler is Better: Few-shot Semantic Segmentation with Classifier Weight Transformer. In Proceedings of International Conference on Computer Vision (ICCV), 2021. 1, 2, 6" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 241, + 545, + 306 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 241, + 545, + 306 + ], + "spans": [ + { + "bbox": [ + 308, + 241, + 545, + 306 + ], + "type": "text", + "content": "[20] Wenjie Luo, Yujia Li, Raquel Urtasun, and Richard Zemel. Understanding the effective receptive field in deep convolutional neural networks. In Proceedings of the 30th International Conference on Neural Information Processing Systems, NIPS'16, page 4905-4913, Red Hook, NY, USA, 2016. Curran Associates Inc. 4, 8" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 308, + 547, + 352 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 308, + 547, + 352 + ], + "spans": [ + { + "bbox": [ + 308, + 308, + 547, + 352 + ], + "type": "text", + "content": "[21] Juhong Min, Dahiyun Kang, and Minsu Cho. Hypercorrelation Squeeze for Few-Shot Segmentation. In Proceedings of International Conference on Computer Vision (ICCV), pages 6941-6952, 2021. 1, 2, 3, 4, 5, 6, 8, 9" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 354, + 545, + 408 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 354, + 545, + 408 + ], + "spans": [ + { + "bbox": [ + 308, + 354, + 545, + 408 + ], + "type": "text", + "content": "[22] Seonghyeon Moon, Samuel S. Sohn, Honglu Zhou, Sejong Yoon, Vladimir Pavlovic, Muhammad Haris Khan, and Mubasir Kapadia. HM: Hybrid Masking for Few-Shot Segmentation. In Proceedings of European Conference on Computer Vision (ECCV), pages 506-523, 2022. 1, 2, 3, 4, 5, 7, 8" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 410, + 545, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 410, + 545, + 453 + ], + "spans": [ + { + "bbox": [ + 308, + 410, + 545, + 453 + ], + "type": "text", + "content": "[23] Khoi Nguyen and Sinisa Todorovic. Feature Weighting and Boosting for Few-Shot Segmentation. In Proceedings of International Conference on Computer Vision (ICCV), 2019, 1, 2, 3, 4, 8, 9" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 455, + 545, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 455, + 545, + 521 + ], + "spans": [ + { + "bbox": [ + 308, + 455, + 545, + 521 + ], + "type": "text", + "content": "[24] Ozan Oktay, Jo Schlemper, Loic Le Folgoc, Matthew C. H. Lee, Mattias P. Heinrich, Kazunari Misawa, Kensaku Mori, Steven G. McDonagh, Nils Y. Hammerla, Bernhard Kainz, Ben Glocker, and Daniel Rueckert. Attention U-Net: Learning Where to Look for the Pancreas. In Medical Imaging with Deep Learning (MIDL), 2018. 5, 9" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 522, + 545, + 577 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 522, + 545, + 577 + ], + "spans": [ + { + "bbox": [ + 308, + 522, + 545, + 577 + ], + "type": "text", + "content": "[25] Kate Rakelly, Evan Shelhamer, Trevor Darrell, Alyosha A. Efros, and Sergey Levine. Conditional Networks for Few-Shot Semantic Segmentation. In Workshop Track Proceedings of International Conference on Learning Representations (ICLR), 2018. 1, 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 578, + 545, + 633 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 578, + 545, + 633 + ], + "spans": [ + { + "bbox": [ + 308, + 578, + 545, + 633 + ], + "type": "text", + "content": "[26] Joseph Redmon, Santosh Divvala, Ross Girshick, and Ali Farhadi. You only look once: Unified, Real-time Object Detection. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 779-788, 2016. 1" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 635, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 635, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 635, + 545, + 689 + ], + "type": "text", + "content": "[27] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster R-CNN: Towards Real-time Object Detection with Region Proposal Networks. Proceedings of Advances in Neural Information Processing Systems (NeurIPS), 28, 2015. 1" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 690, + 545, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 690, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 308, + 690, + 545, + 714 + ], + "type": "text", + "content": "[28] Amirreza Shaban, Shray Bansal, Zhen Liu, Irfan Essa, and Byron Boots. One-Shot Learning for Semantic Segmenta" + } + ] + } + ], + "index": 24 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19275" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 620 + ], + "type": "list", + "angle": 0, + "index": 11, + "blocks": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "text", + "content": "tion. In Proceedings of British Machine Vision Conference (BMVC), pages 167.1-167.13, 2017. 2, 4" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 288, + 171 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 288, + 171 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 288, + 171 + ], + "type": "text", + "content": "[29] Xinyu Shi, Dong Wei, Yu Zhang, Donghuan Lu, Munan Ning, Jiashun Chen, Kai Ma, and Yefeng Zheng. Dense cross-query-and-support attention weighted mask aggregation for few-shot segmentation. In Computer Vision - ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XX, page 151-168, 2022. 3, 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 174, + 288, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 174, + 288, + 217 + ], + "spans": [ + { + "bbox": [ + 48, + 174, + 288, + 217 + ], + "type": "text", + "content": "[30] Mennatullah Siam, Boris N. Oreshkin, and Martin Jägersand. AMP: Adaptive Masked Proxies for Few-Shot Segmentation. In Proceedings of International Conference on Computer Vision (ICCV), pages 5248-5257, 2019. 1, 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 219, + 288, + 272 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 219, + 288, + 272 + ], + "spans": [ + { + "bbox": [ + 48, + 219, + 288, + 272 + ], + "type": "text", + "content": "[31] Zhuotao Tian, Hengshuang Zhao, Michelle Shu, Zhicheng Yang, Ruiyu Li, and Jiaya Jia. Prior Guided Feature Enrichment Network for Few-Shot Segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 2020. 1, 2, 3, 4, 5, 8, 9" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 274, + 288, + 328 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 274, + 288, + 328 + ], + "spans": [ + { + "bbox": [ + 48, + 274, + 288, + 328 + ], + "type": "text", + "content": "[32] Haochen Wang, Xudong Zhang, Yutao Hu, Yandan Yang, Xianbin Cao, and Xiantong Zhen. Few-Shot Semantic Segmentation with Democratic Attention Networks. In Proceedings of European Conference on Computer Vision (ECCV), pages 730-746, 2020. 1, 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 331, + 288, + 384 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 331, + 288, + 384 + ], + "spans": [ + { + "bbox": [ + 48, + 331, + 288, + 384 + ], + "type": "text", + "content": "[33] Kaixin Wang, Jun Hao Liew, Yingtian Zou, Daquan Zhou, and Jiashi Feng. PANet: Few-Shot Image Semantic Segmentation With Prototype Alignment. In Proceedings of International Conference on Computer Vision (ICCV), 2019, 1, 2, 3, 4, 8, 9" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 386, + 288, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 386, + 288, + 430 + ], + "spans": [ + { + "bbox": [ + 48, + 386, + 288, + 430 + ], + "type": "text", + "content": "[34] Boyu Yang, Chang Liu, Bohao Li, Jianbin Jiao, and Ye Qixiang. Prototype Mixture Models for Few-shot Semantic Segmentation. In Proceedings of European Conference on Computer Vision (ECCV), 2020. 1, 2, 3, 4, 8, 9" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 431, + 288, + 485 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 431, + 288, + 485 + ], + "spans": [ + { + "bbox": [ + 48, + 431, + 288, + 485 + ], + "type": "text", + "content": "[35] Chi Zhang, Guosheng Lin, Fayao Liu, Rui Yao, and Chunhua Shen. CANet: Class-Agnostic Segmentation Networks With Iterative Refinement and Attentive Few-Shot Learning. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2019. 1, 2, 3, 4, 8, 9" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 487, + 288, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 487, + 288, + 529 + ], + "spans": [ + { + "bbox": [ + 48, + 487, + 288, + 529 + ], + "type": "text", + "content": "[36] Gengwei Zhang, Guoliang Kang, Yi Yang, and Yunchao Wei. Few-Shot Segmentation via Cycle-Consistent Transformer. arXiv preprint arXiv:2106.02320, 2021. 2, 3, 4, 6, 8, 9" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 532, + 288, + 574 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 532, + 288, + 574 + ], + "spans": [ + { + "bbox": [ + 48, + 532, + 288, + 574 + ], + "type": "text", + "content": "[37] Xiaolin Zhang, Yunchao Wei, Yi Yang, and Thomas Huang. SG-One: Similarity Guidance Network for One-Shot Semantic Segmentation. IEEE Transactions on Cybernetics, 50:3855-3865, 2020. 1, 2, 3, 4, 9" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 576, + 288, + 620 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 576, + 288, + 620 + ], + "spans": [ + { + "bbox": [ + 48, + 576, + 288, + 620 + ], + "type": "text", + "content": "[38] Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, and Jiaya Jia. Pyramid Scene Parsing Network. In Proceedings of IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 6230-6239, 2017. 1" + } + ] + } + ], + "index": 10 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19276" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/9bf308bf-7020-43ef-9313-33d2e81da894_content_list.json b/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/9bf308bf-7020-43ef-9313-33d2e81da894_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..aa53b78ab27e6b12199e8849fa4c3ea153b4906e --- /dev/null +++ b/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/9bf308bf-7020-43ef-9313-33d2e81da894_content_list.json @@ -0,0 +1,1445 @@ +[ + { + "type": "text", + "text": "MST-compression: Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree", + "text_level": 1, + "bbox": [ + 106, + 128, + 867, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Quang Hieu Vo, Linh-Tam Tran, Sung-Ho Bae, Lok-Won Kim, Choong Seon Hong* \nDepartment of Computer Science and Engineering, Kyung Hee University", + "bbox": [ + 153, + 203, + 820, + 239 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{2019310178, tamlt, shbae, lwk, cshong}@khu.ac.kr", + "bbox": [ + 267, + 241, + 700, + 255 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 291, + 313, + 306 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Binary neural networks (BNNs) have been widely adopted to reduce the computational cost and memory storage on edge-computing devices by using one-bit representation for activations and weights. However, as neural networks become wider/deeper to improve accuracy and meet practical requirements, the computational burden remains a significant challenge even on the binary version. To address these issues, this paper proposes a novel method called Minimum Spanning Tree (MST) compression that learns to compress and accelerate BNNs. The proposed architecture leverages an observation from previous works that an output channel in a binary convolution can be computed using another output channel and XNOR operations with weights that differ from the weights of the reused channel. We first construct a fully connected graph with vertices corresponding to output channels, where the distance between two vertices is the number of different values between the weight sets used for these outputs. Then, the MST of the graph with the minimum depth is proposed to reorder output calculations, aiming to reduce computational cost and latency. Moreover, we propose a new learning algorithm to reduce the total MST distance during training. Experimental results on benchmark models demonstrate that our method achieves significant compression ratios with negligible accuracy drops, making it a promising approach for resource-constrained edge-computing devices.", + "bbox": [ + 76, + 323, + 473, + 717 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 744, + 209, + 760 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Deep Neural Networks (DNNs) have been widely applied in many artificial intelligence applications, especially vision tasks with high accuracy [27, 14]. However, the cost of computation and massive storage burden is significantly challenging to deploy DNNs on embedded systems such as mobile devices and other resource-constrained platforms. Many approaches have been proposed and demonstrated", + "bbox": [ + 75, + 771, + 468, + 878 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/77ff917b2ac1456b9f1df437dd8c7e5f39e49923d42ff58e8ab714152a0b0bb2.jpg", + "image_caption": [ + "Figure 1. Illustration of kernel compression for BNNs with the Kmean method (a) and the shortest Hamiltonian path (b), in which adding red connections can further reduce the computational cost for both of them." + ], + "image_footnote": [], + "bbox": [ + 576, + 287, + 705, + 421 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/22117411980b0e4eecf7b0650e325a8db2e9a65a0a3cd171a9daa7aa640e7857.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 738, + 287, + 810, + 421 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "their effectiveness in reducing energy and resources while maintaining the deep models' accuracy, including pruning [12], quantization [7], distillation [15], and efficient hardware implementation [6]. Among these methods, quantization with less bit-width for parameter and activation representation is widely used due to its great benefits and possibility in most practical applications.", + "bbox": [ + 496, + 503, + 890, + 611 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Binarized neural network is a particular form of the quantization method in which weight values and activations are converted to 1-bit values. Accordingly, multiplications and accumulation operations can be replaced by XNOR and Popcount operations [7], respectively. In addition, batch normalization is simplified to a threshold comparison [31], while the pooling can be performed with OR operations [30]. Consequently, the compression ratio on memory storage and computational cost is significantly improved, leading to remarkable performance acceleration. Nevertheless, the accuracy degradation is the trade-off of minimizing the bit-width as BNN. Thus, most previous works focus on reducing this accuracy gap [25, 4, 33, 22, 20, 33, 23].", + "bbox": [ + 496, + 611, + 892, + 808 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Meanwhile, compressing BNNs has not received much attention, with only a few prominent methods [32, 9, 31, 17], where the kernel compression [9, 31] gives impressive results with roughly $50\\%$ resources reduction. In particular, given a binary convolution, inspired by an observation that an output channel can be calculated using another out", + "bbox": [ + 496, + 809, + 893, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding Author", + "bbox": [ + 94, + 886, + 223, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "6091", + "bbox": [ + 482, + 944, + 513, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "put channel and outputs of XNOR operations using weights that respectively differ from the reused channel's weights [9], authors in [31, 9] proposed to construct a fully connected graph, in which each vertex corresponds to an output channel, and distance between two vertices is the number of different values between two weight sets used for the two output channels. Then, based on the graph, they use the K-mean cluster and shortest Hamiltonian path to reorder the convolution output calculation, aiming to reduce the number of XNOR operations. However, these approaches have yet to fully minimize the computational cost as output channels can use less computation. Indeed, Figure 1 (a) illustrates an example of the K-mean method, where two vertices are considered centers of two groups. Two output channels corresponding to centers are fully calculated1, while other vertices reuse their centers for calculation. However, adding a connection between the two centers would enable one to utilize the rest with less computation cost. Additionally, in the shortest Hamiltonian path shown in Figure 1 (b), there may exist a connection to a specific vertex that is shorter than the connection from the preceding vertex in the path, leading to a lower required number of operations for this vertex. Furthermore, time complexity poses a challenge in these methods [1, 13], resulting in longer exploration times.", + "bbox": [ + 76, + 90, + 472, + 467 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To more effectively minimize the number of XNOR operations with the mentioned observation, in all connections to a specific vertex, the minimum connection must be selected to minimize the computation cost for this vertex. In addition, all of these selected connections must be included in a subgraph that visits all vertices exactly once to ensure that only one output channel is fully calculated. As a result, a MST is the only structure that can fulfill these requirements. Therefore, this paper leverages the MST to reorder binary convolution output calculations. Figure 2 shows a simple example of reordering calculation on a convolution. In this example, only the output channel 4 is fully calculated with $C_{in} \\times M \\times M$ bit-weight values. In contrast, other channels are calculated using output channel 4, following the MST direction.", + "bbox": [ + 75, + 468, + 472, + 696 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "On the other hand, to maximize the advantages of the MST, we further minimize the MST distance of all convolution layers with a new learning algorithm right during the training stage. Besides, we propose a hardware accelerator for BNNs applying the MST compression to demonstrate the feasibility and effectiveness of the method related to hardware resources. To the best of our knowledge, this method gives the highest compression ratio with implementation from learning for compression to acceleration. In summary, the following are contributions of this paper:", + "bbox": [ + 75, + 696, + 472, + 848 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "- We introduce and analyze the effectiveness of the MST", + "bbox": [ + 94, + 859, + 470, + 876 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/ffb0d321e668f307b83d20e2ce2aaf7a50bcf960cbe5a2f54c32cc9606afaee8.jpg", + "image_caption": [ + "Figure 2. The process of arranging the order of computation on a binary convolution layer, in which output channel 4 is fully calculated first. Then, the output channel 4 is used to calculate channel 1, channel 2 and channel 3." + ], + "image_footnote": [], + "bbox": [ + 513, + 89, + 890, + 239 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "in reducing the computational cost for the inference on a binary convolution layer.", + "bbox": [ + 529, + 338, + 890, + 368 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose a training algorithm that can reduce the MST distance and depth right during the training process, which consequently maximizes the compression ratio for inference implementation.", + "- We provide the corresponding hardware acceleration for the proposed method with high throughput and better resource efficiency, compared to related works [3, 30, 31, 10]." + ], + "bbox": [ + 517, + 378, + 890, + 512 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The experiments are performed for BNNs including VGG-small [5], ResNet-18/20 [14] on CIFAR-10 dataset [18], and ResNet-18/34 [14] on ImageNet [26]. The results show that the proposed approach gives a higher compression ratio than the previous works [32]. Compared to the baseline [33], our method reduces up to $13.5 \\times$ the convolution parameters and $5.51 \\times$ bit-wise operations on the same model with an acceptable accuracy degradation. Regarding hardware acceleration, we conduct the experiments for a BNN with the same structure as the baseline [31] and apply the proposed approach. Compared to the baseline [31], hardware deployments demonstrate that BNNs with our method save $1.8 \\times$ LUTs, and $1.81 \\times$ area efficiency while maintaining the acceleration speed and accuracy.", + "bbox": [ + 496, + 527, + 890, + 739 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 753, + 640, + 768 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Training neural networks with binary weights and activations were first introduced by Coubariaux et al. [7] and then rapidly gained attention from the community due to the high compression ratio. However, accuracy drop is a critical problem of this direction, while compression is still highly demanded. Various techniques are proposed to further compress and improve accuracy based on the binary property.", + "bbox": [ + 496, + 779, + 890, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_footnote", + "text": "${}^{1}$ calculated with ${C}_{in} \\times M \\times M$ XNORs,denoted in Figure 2", + "bbox": [ + 94, + 886, + 431, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "6092", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "For accuracy improvement, Rastegari et al. [25] proposed adding a scaling factor to the convolution to reduce the quantization error. To generalize this idea aiming to enhance accuracy, the authors in [4] extended this factor dimension and enabled its training option as a learnable parameter. Besides, instead of using the Straight Through Estimation (STE) method [2], Liu et al. [23], and Lin et al. [20] proposed using a piece-wise linear and training-aware approximation function, respectively, to approximate the sign function gradient better. Meanwhile, some previous works introduced both new optimization techniques and corresponding BNN to shrink the accuracy gap entirely [22, 21, 28, 24]. For example, based on Bi-real Net in [23], authors in [22] proposed new sign and activation functions to shift and reshape activation distribution with a new baseline neural network model that can boost the performance. Other works look at the binary characteristics from deeper perspectives to limit information loss [20, 28, 33]. For example, KL divergence is employed in [28] to minimize the difference between the distribution of binary and real-weight counterparts. Xu et al. [33] observed the low probability of changing large full-precision weight when binarizing and proposed the ReCu function to revive the death weights, leading to lower quantization error.", + "bbox": [ + 76, + 90, + 472, + 454 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Binary model compression has received less attention as only a few techniques have been proposed so far. Specifically, Lee et al. [19] proposed an encryption algorithm to compress binary weights with lower than 1-bit per weight, and XOR-gate networks are used to decrypt the inference task. Similarly, Sub-bit Neural Networks (SNN) [32] proposed using lower than 9 bits for each $3 \\times 3$ binary kernel based on the scattered 9-bit kernel distribution. Other proposed compression methods provided only hardware techniques for inference implementation. Authors in [31, 9] proposed BNN hardware architectures using weight/input reuse with different calculation orders for convolution to reduce hardware overhead. Kim et al. [17] introduces kernel decomposition that can reduce the computational cost by sharing one base output for all channels.", + "bbox": [ + 75, + 459, + 472, + 686 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Background", + "text_level": 1, + "bbox": [ + 76, + 717, + 205, + 734 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "This section briefly describes how to construct a binary convolution layer and the related optimization methods. For a convolution layer with $C_{in}$ input channels, $C_{out}$ output channels, and kernel size $M$ , weights and activations are denoted by $\\mathcal{W}^r \\in \\mathbb{R}^n$ and $A^r \\in \\mathbb{R}^m$ , where $n = C_{out} \\times C_{in} \\times M \\times M$ and $m = C_{in} \\times W_{in} \\times H_{in}$ . $W_{in} \\times H_{in}$ represents input feature map size. To simplify the computation and reduce memory storage, in a binary convolution layer, the binarization of activations $\\mathcal{A}^b \\in \\{\\pm 1\\}^m$ and weights $\\mathcal{W}^b \\in \\{\\pm 1\\}^n$ is acquired by the fol", + "bbox": [ + 76, + 750, + 472, + 902 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/0934753088b843d1756c7c6c4408910c4840ba22359ed9e9593ef8fbde5a8cd0.jpg", + "image_caption": [ + "Figure 3. Weight-reuse method description. Here, the red line is counting the number of elements, the green line is summing all elements. $P_{12}$ is $\\sum_{j=1}^{d_{12}} \\mathrm{XNOR}(\\mathcal{A}_{2j}, \\mathcal{W}_{2j})$ , and $Y_{2}$ is $2(P_{1} - d_{12} + 2P_{12}) - C_{in} \\times M \\times M$ ." + ], + "image_footnote": [], + "bbox": [ + 511, + 90, + 885, + 315 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "lowing sign function [25],", + "bbox": [ + 500, + 398, + 676, + 412 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nx ^ {b} = \\operatorname {S i g n} (x) = \\left\\{ \\begin{array}{l} + 1, \\text {i f} x \\geq 0, \\\\ - 1, \\text {o t h e r w i s e .} \\end{array} \\right. \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 570, + 420, + 890, + 460 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "If $-1$ is substituted by 0 to represent a negative value for $\\mathcal{A}^b$ and $\\mathcal{W}^b$ , the output convolution operation of the $i^{th}$ channel now is reformulated as in Eq. (2) [31].", + "bbox": [ + 496, + 469, + 893, + 516 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nY _ {i} = (2 \\sum_ {j = 1} ^ {C _ {i n} M M} \\operatorname {X N O R} \\left(\\mathcal {A} _ {i j} ^ {b}, \\mathcal {W} _ {i j} ^ {b}\\right) - C _ {i n} \\times M \\times M) \\odot \\alpha , \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 500, + 523, + 890, + 579 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\sum_{1}^{C_{in}\\times M\\times M}\\mathrm{XNOR}(\\mathcal{A}_{ij}^{b},\\mathcal{W}_{ij}^{b})$ is the number of set-bits (Popcount) of the output channel $i^{th}$ , $\\odot$ is the element-wise multiplication, and $C_{in}\\times M\\times M$ is the number of bit-wise XNOR operations used to calculate one output channel. The scaling factor $\\alpha$ is added as a learnable parameter to lessen quantization error [25]. For backward propagation, following [23], the STE [2] method is used for the approximation gradient on weights, while the piecewise polynomial function [23] is used for gradient approximation on activations.", + "bbox": [ + 496, + 577, + 893, + 731 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To further compress the BNN models, in this paper, we apply the weight reuse method [31] for the inference task. Accordingly, given the $l^{th}$ binary convolution, as shown in Figure 3, we denote $P_{i}$ and $P_{j}$ as the output of the Popcount operations of the output channels $i^{th}$ and $j^{th}$ , respectively. All binary weights of the layer are divided into $C_{out}$ weight sets $w_{b}^{li} \\in \\{\\pm 1\\}^{C_{in} \\times M \\times M}$ , where $i = 1,2,\\dots,C_{out}$ and each weight set is used to calculate for an output channel. $d_{ij}$ is the number of weight bits in the $w_{b}^{li}$ that differ from the $w_{b}^{lj}$ , compared one-to-one respectively. $P_{ij}$ is the sum of XNOR operations with the", + "bbox": [ + 496, + 732, + 893, + 902 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "6093", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/b54dd59fcb9bd5ed24a2c6fd3f40c58b51efc81a0a552c82bdb14eb601b0346e.jpg", + "image_caption": [ + "Figure 4. Comparison between the computation process of a standard binary convolution and our method in BNN acceleration. Instead of fully computing all $C_{in} \\times M \\times M$ XNOR operations for each layer, our method provides an optimal order of the calculation using the MST to minimize the number of XNOR operations and total parameters." + ], + "image_footnote": [], + "bbox": [ + 83, + 89, + 467, + 527 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "weights of the channel $j^{th}$ that differ from the $i^{th}$ counterpart. To calculate the output channel $j^{th}$ from the output channel $i^{th}$ , we use Eq. (3).", + "bbox": [ + 75, + 628, + 470, + 676 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nY _ {j} = 2 \\left(P _ {i} - d _ {i j} + 2 P _ {i j}\\right) - C _ {i n} \\times M \\times M. \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 125, + 686, + 468, + 705 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. Methodology", + "text_level": 1, + "bbox": [ + 76, + 715, + 212, + 733 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Minimum Spanning Tree for BNN Acceleration", + "text_level": 1, + "bbox": [ + 76, + 741, + 468, + 758 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "For a binary convolution layer, we construct a fully connected graph in which each vertex corresponds to an output channel. The distance between two vertices $i$ and $j$ is $d_{ij}$ . As shown in Eq. (3), an output channel $j$ can be calculated via the Popcount of an output channel $i$ and the Popcount of $d_{ij}$ XNOR operations. That means the number of XNOR operations executed for the output channel $j$ is the distance $d_{ij}$ . Based on this observation, to minimize the number of XNOR operations used for all out", + "bbox": [ + 75, + 763, + 470, + 900 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "put channels, we need a sub-graph that includes all vertices with the minimum total edge distances, which is named an MST [29]. Returning to the example in Figure 2, Figure 4 illustrates the computation process of this convolution example with the standard and proposed approach. Specifically, in the standard direction, each output channel needs 9 XNOR operations, while in our direction, only the $4^{th}$ output channel is fully computed by 9 XNOR operations, and the $1^{st}, 2^{nd}, 3^{rd}$ output channels reuse the output channel $4^{th}$ with 2, 3, 2 XNOR operations, respectively. Accordingly, the compression ratio for this example is $(2 + 3 + 2 + 3 \\times 3) / (4 \\times 1 \\times 3 \\times 3) = 0.44$ . In general, we can reduce the computational cost for a convolution layer with the following ratio:", + "bbox": [ + 496, + 90, + 893, + 303 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {R} = \\frac {\\sum_ {j \\neq r o o t} ^ {C _ {o u t}} d _ {i j} + C _ {i n} \\times M \\times M}{C _ {o u t} \\times C _ {i n} \\times M \\times M}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 568, + 310, + 890, + 349 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $i$ is the parent of the vertex $j$ . If $j$ is the root of the MST, this output uses $C_{in} \\times M \\times M$ binary weight values.", + "bbox": [ + 496, + 354, + 890, + 385 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Regarding parameters, because the streaming architecture described in Sec. 4.3 is fully implemented with all layers on the FPGA platform, weights' locations can be converted to connections from inputs to the correct XNORs and corresponding weight values at the circuit level. Thus, our proposed method counts only the parameters we need for XNOR logic gates, as shown in Figure 4.", + "bbox": [ + 496, + 386, + 890, + 491 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Number of bit-wise operations. Compared with the previous approaches [31, 9], in a binary convolution layer, the proposed method can better reduce the number of XNORs and parameters. Firstly, as explained in the previous section, adding connections among centers leads to less computation for the K-mean approach [31] as in Eq. (5).", + "bbox": [ + 496, + 491, + 890, + 597 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\sum_ {j} d _ {i j} + C _ {i n} \\times M \\times M < \\sum_ {j \\notin C} d _ {i j} + R \\times C _ {i n} \\times M \\times M, \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 506, + 602, + 890, + 636 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $C$ includes all centers, $R$ is the number of centers. Furthermore, adding connections among centers also creates a spanning tree, whose computational cost is always equal to or higher than using an MST. Secondly, in [9], the authors proposed using the shortest Hamiltonian path to arrange the computation order. Because this path visits all vertices exactly once, the shortest Hamiltonian path is also a spanning tree. Therefore, the number of XNOR bit-wise operations using an MST method is equal to or lower than the shortest Hamiltonian path.", + "bbox": [ + 496, + 643, + 890, + 794 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Exploration time. The MST is faster and less complex for finding the computation order, compared to previous work [9, 31]. Indeed, the MST is found by Prim's algorithm with the complexity of $O(V^2)$ [29], where $V$ is the number of vertices. In contrast, the K-mean algorithm requires $O(V^2 G)$ [13] time complexity, where $G$ denotes the number of groups. Since the optimal number of groups varies", + "bbox": [ + 496, + 795, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "6094", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/921cf3b22ea120edb42a983200a658268c1be835f1007d23d06cee503cfd5235.jpg", + "image_caption": [ + "Figure 5. a) The computation tree's depth using the K-mean cluster. b) The computation tree's depth using the shortest Hamiltonian path. c) The computation tree's depth using the MST." + ], + "image_footnote": [], + "bbox": [ + 116, + 88, + 433, + 258 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/8f4d2c7c1776d88729a813df000fe78ef8b4c8f3f640fa844e90bc7a2cabfae3.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
LHamiltonianK-meanMST
Bit-OpsTimeBit-OpsTimeBit-OpsTime
11.08 M31.3 s1.33 M0.090 s1.07 M0.021 s
21.09 M32.9 s1.30 M0.075 s1.06 M0.021 s
31.07 M32.6 s1.30 M0.085 s1.05 M0.023 s
41.10 M32.7 s1.33 M0.076 s1.08 M0.021 s
51.11 M32.5 s1.32 M0.115 s1.09 M0.020 s
61.09 M32.5 s1.33 M0.086 s1.08 M0.021 s
", + "bbox": [ + 83, + 325, + 464, + 425 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Table 1. Bit-Ops and running time w.r.t. different approaches for reordering calculation on the first 6 convolution layers of ResNet20 with 16 output channels.", + "bbox": [ + 75, + 434, + 470, + 477 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "across convolutions, extra time is needed to determine this number for each case. Meanwhile, the shortest Hamiltonian path has a much higher time complexity of $O(V^{2}2^{V})$ [1], making it challenging to apply in practical settings. To estimate these approaches for practical operation, we perform experiments for the first 6 binary convolution layers of ResNet-20 [14] with the weight data trained by [33], while experiments on deeper layers with a larger number of output channels are infeasible even uncompleted for the K-mean and the shortest Hamiltonian path approach due to their longer running times. According to Table 1, the MST approach gives the lowest bit-Ops and exploration time.", + "bbox": [ + 75, + 492, + 468, + 672 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Computation latency. This is one of the factors affecting the resource overhead. This paper focuses on improving the architecture in [31], a streaming acceleration for BNNs. In doing so, the deeper the computation tree, the longer latency between the time output of the first and the last channel comes out. Consequently, the number of added registers (Flip-flops) for synchronization tends to be equal or more for the deeper tree because all output channels must be available at the same clock for the next convolution operation. The exact number of added registers depends on the number of adders executed in a clock period, which is affected by the required frequency, design complexity, and hardware platform. Thus, to evaluate the comprehensive effects of the depth with practical implementations, the experiments related to this comparison are provided in Sec. 5.", + "bbox": [ + 75, + 674, + 470, + 901 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Figure 5 visually describes the depth of the MST, K-mean cluster, and the shortest Hamiltonian path approach. Accordingly, the depths of the K-mean method and the shortest Hamiltonian path are always 1 and $V$ , respectively. Meanwhile, the MST's depth can range from 1 to $V$ , depending on the graph structure. Therefore, the proposed method is always better than the shortest Hamiltonian path in all aspects (number of operations, latency, running time). Meanwhile, the K-mean method gives a better latency but much worse for the rest. After exploring an MST for the posttraining stage to limit the impact of the tree depth on latency and resources, we continue finding a new root that makes the depth of the new tree minimum.", + "bbox": [ + 496, + 90, + 893, + 287 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Learning Optimization", + "text_level": 1, + "bbox": [ + 498, + 296, + 714, + 313 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "According to the observation mentioned earlier, to enhance the benefits of the MST approach, we propose a simple learning method that can further reduce the MST depth and total MST distance over a BNN model. Specifically, to make the training converged, instead of directly optimizing the MST, we cluster weight sets $(\\mathrm{w}_b^{li})$ to different groups and try to reduce the distance among weight sets in each group by optimizing the distances from all weight sets to fixed centers. In doing so, given the $l^{th}$ binary convolution layer of a BNN model, we first randomly sample a binary center subset $\\mathbb{C}_l \\subset \\{\\pm 1\\}^{C_{in} \\times M \\times M}$ and $|\\mathbb{C}_l| = N_l$ . Then, we explore the nearest center in $\\mathbb{C}_l$ for every $\\mathrm{w}_b^{li}$ and save it into a dictionary $\\mathcal{C}$ using Eq. (6).", + "bbox": [ + 496, + 320, + 893, + 517 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {C} \\left(\\mathrm {w} _ {b} ^ {l i}\\right) = \\underset {x} {\\operatorname {a r g m i n}} \\left(\\sum_ {i = 1} ^ {C _ {i n} \\times M \\times M} \\| x - \\mathrm {w} _ {b} ^ {l i} \\|\\right); x \\in \\mathbb {C} _ {l}. \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 511, + 523, + 890, + 566 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "On the other hand, the total distance from every weight sets to its center is added to the loss function and compels the training to minimize both the cross-entropy loss and the distance among weight sets in a group (distance loss). To strike a balance between optimizing the original and distance loss, we adjust a hyper-parameter $\\lambda$ to achieve an optimal ratio for different BNN models. Besides, a $\\gamma$ parameter serves as a hyper-parameter to control the priority of the original and additional loss during the training. This parameter varies following a specific scheduler during the training process. Particularly, the algorithm prioritizes reducing the MST distance and depth during the initial training phase and gradually shifting its focus toward accuracy at the end of the process. The new loss function is shown in Eq. (7), where $\\mathcal{L}_0(\\mathrm{input},\\mathrm{w})$ is the original loss function. Forward processes are summarized in Algorithm 1.", + "bbox": [ + 496, + 575, + 893, + 819 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} (\\text {i n p u t}, \\mathrm {w}) = \\mathcal {L} _ {0} (\\text {i n p u t}, \\mathrm {w}) + \\lambda \\gamma \\sum_ {i} \\| \\mathcal {C} \\left(\\mathrm {w} _ {b} ^ {i}\\right) - \\mathrm {w} _ {b} ^ {i} \\| ^ {2}, \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 506, + 828, + 890, + 859 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "It is noticeable that we use pre-trained BNN models for the learning process to avoid diverging during distance op", + "bbox": [ + 498, + 869, + 893, + 902 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "6095", + "bbox": [ + 482, + 944, + 514, + 957 + ], + "page_idx": 4 + }, + { + "type": "code", + "sub_type": "algorithm", + "code_caption": [ + "Algorithm 1 Forward propagation for the training process." + ], + "code_body": "Require: Input data, pre-train full-precision weight (w), threshold $(\\theta)$ learning rate $(\\eta)$ MST scaling factor $(\\lambda)$ \n1: Load pre-train weight (w) \n2: for epoch $= 1\\rightarrow E$ do \n3: $\\mathcal{L}_{mst} = 0$ \n4: for $l = 1$ to L do \n5: $\\mathrm{w}_b^l = \\mathrm{Sign}(\\mathrm{w}_l)$ [33] \n6: $\\mathrm{a}_b^{l - 1} = \\mathrm{Sign}(\\mathrm{a}_{l - 1})$ \n7: for i = 1 to Cout do \n8: Update centers for $\\mathrm{w}_b^l$ . \n9: $\\mathcal{C}(\\mathrm{w}_b^{li}) = \\underset {x}{\\operatorname{argmin}}(\\sum_{i = 1}^{C_{in}\\times M\\times M}\\| x - \\mathrm{w}_b^{li}\\|);x\\in \\mathbb{C}_l$ \n10: $\\mathcal{L}_{MST} = \\mathcal{L}_{MST} + \\sum \\| \\mathcal{C}(\\mathrm{w}_b^{li}) - \\mathrm{w}_b^{li}\\| ^2$ \n11: end for \n12: $\\mathrm{a_l} = (\\mathrm{w_b^l*}\\mathrm{a_b^{l - 1}})\\odot \\alpha_l$ \n13: end for \n14: Compute total loss: $\\mathcal{L} = \\mathcal{L}_0 + \\lambda *\\gamma *\\mathcal{L}_{MST}$ \n15: end for", + "bbox": [ + 78, + 108, + 468, + 325 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "timization time. In this paper, results from ReCu [33] are used and considered the baseline for comparison.", + "bbox": [ + 75, + 353, + 468, + 383 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Streaming Acceleration", + "text_level": 1, + "bbox": [ + 76, + 393, + 294, + 409 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Inspired by the streaming architecture in [31], this paper proposes an entire BNN high-speed architecture for BNN models applying our compression method. Specifically, the hardware architecture of a binary convolution layer is shown in Figure 6, in which the process is divided into two steps: 1) loading the input feature map to a line buffer and 2) executing XNOR + Popcount operation.", + "bbox": [ + 75, + 417, + 468, + 521 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Loading input. Given a binary convolution layer with $M = 3$ , padding size $= 1$ , firstly, $C_{in}$ input feature maps are gradually loaded into $C_{in}$ line buffers with the size $2 \\times W_{in} + 3$ . When $W_{in} + 2$ registers in each line buffer are filled, $C_{in} \\times 3 \\times 3$ input pixels are selected from the line buffers for the convolution (XNOR + Popcount) operation. In standard calculation approach, the number of XNOR operations used for a binary convolution is $C_{out} \\times C_{in} \\times M \\times M$ . These operations can be separated into $C_{out}$ sub-operations corresponding to $C_{out}$ output channels; each sub-operation includes $C_{in} \\times M \\times M$ XNOR bit-operations and requires $C_{in} \\times M \\times M$ corresponding input pixels and weight values. In this proposed architecture, the difference is that the number of inputs for a particular sub-operation is lower than $C_{in} \\times M \\times M$ and equal to the distance between the corresponding vertex and parent vertex as in the constructed graph, except the sub-operation for the root vertex requiring full calculation with $C_{in} \\times M \\times M$ XNORs.", + "bbox": [ + 75, + 523, + 470, + 794 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Perform convolution. This step executes the convolution operation with the order of calculation following the MST. As shown in Figure 6, the output of a specific PE (red arrow) is reused for the next PE to reduce computational cost. The PE for the output channel $i^{th}$ needs $d_{ij}$ weight values and executes $d_{ij}$ XNOR operations with the corresponding Popcount operation, where $j$ is the parent", + "bbox": [ + 75, + 795, + 468, + 901 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/24fc45c146751253c6dc920dec9d9f014fee081123fc86c2039f5eeb0e738390.jpg", + "image_caption": [ + "Figure 6. High-speed hardware accelerator for a binary convolution layer, where the XNORs are simplified with NOT or simple straight connection, while computation on each PE corresponding to each output channel is executed gradually with the MST." + ], + "image_footnote": [], + "bbox": [ + 504, + 90, + 890, + 281 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "vertex of the vertex $i^{th}$ . Besides, to eliminate memory for convolution weight storage, XNOR operations are simplified to NOT gate or straight connection. In terms of timing violations, we pipeline the Popcount operation by adding register lines among the adder tree to reduce computation complexity in a clock cycle. The exact number of register lines depends on the MST depth, frequency and hardware platform. Thus, depending on practical implementations, we adjust this number to meet the timing requirements.", + "bbox": [ + 496, + 368, + 892, + 505 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 500, + 520, + 632, + 537 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this section, we conduct experiments including software and hardware implementation to show the effectiveness of the proposed method for BNN compression. Training experiments are executed with the popular datasets CIFAR-10 and ImageNet via Pytorch, while hardware implementation is performed on the Xilinx FPGA platforms.", + "bbox": [ + 496, + 547, + 890, + 638 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Learning and hardware implementation", + "text_level": 1, + "bbox": [ + 500, + 650, + 843, + 666 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Training implementation: Because our proposed method is independent of other BNN accuracy optimization methods, in this paper, we select training results from the ReCU approach in [33] as a case study for further compressing. In doing so, VGG-small, ResNet-18/20 models are used to evaluate on CIFAR-10 dataset, while ResNet-18/34 are used for ImageNet. Regarding training in detail, we keep the configuration as in [33], except for the learning rate of 0.1. In addition, the $\\lambda$ value is adjusted depending on the training models, datasets, and focused objectives. Meanwhile, the $\\gamma$ parameter is scheduled following the learning rate. In this paper, when training with CIFAR-10, we select 1e-6 for ResNet-18, 5e-6 for ResNet-20, and 4e-6 for VGG-small. Meanwhile, for ImageNet, we select 1e-6 for ResNet-18 and 1e3 for ResNet-34.", + "bbox": [ + 496, + 674, + 892, + 898 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "6096", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/ff6d24f46fdba1ec89158f7e31442b3bb87c5439ac9bb2efbffbb5383ce29bde.jpg", + "image_caption": [ + "a) MST distances of each layer (L)." + ], + "image_footnote": [], + "bbox": [ + 81, + 88, + 285, + 202 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/d96762b1efc4b4120336a51095a3cb0e1f929b9dd07665213e29cf4cbf3c9772.jpg", + "image_caption": [ + "b) Accuracy curves.", + "Figure 7. MST distance and top-1 % accuracy during the training process, where the Binary VGG-small model and CIFAR-10 dataset is used for the training experiment with 600 epochs." + ], + "image_footnote": [], + "bbox": [ + 285, + 95, + 480, + 202 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/192b7d0c0f5edbb73ff410d5ab7790f4667cefcfafd7627d4ba15ac8a3d22447.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
λMST-depth#Params (Mbit)#Bit-Ops (GOps)Top-1 Acc. mean ± std (%)
1e-797.31.3910.21792.17 ± 0.07
5e-758.30.9980.18492.09 ± 0.06
1e-654.00.8640.16591.99 ± 0.07
5e-644.00.5320.11591.14 ± 0.08
1e-542.30.4220.09890.17 ± 0.14
", + "bbox": [ + 93, + 270, + 452, + 359 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 2. MST depth, number of parameters, bit-Ops, and accuracy w.r.t. different values of $\\lambda$ on CIFAR-10 VGG-small model.", + "bbox": [ + 75, + 369, + 467, + 397 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Hardware implementation: The inference hardware architecture is implemented on a Xilinx FPGA platform called xczu3eg-sbva484 part. Before programming to FPGA, the design is run with the corresponding C/C++ model and simulated via Synopsys VCS. Finally, Vivado 2018.3 is used for the design synthesis and implementation.", + "bbox": [ + 75, + 411, + 467, + 501 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.2. Ablation Studies", + "text_level": 1, + "bbox": [ + 76, + 512, + 240, + 527 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In this section, experimental results and discussion related to hyper-parameter $\\lambda$ , and $\\gamma$ are described.", + "bbox": [ + 75, + 536, + 467, + 566 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Effect of hyper-parameter $\\gamma$ : As explained in Sec. 4.1, an additional loss related to MST distance is added for the learning. The effect of the loss depends on the $\\gamma$ , while the $\\gamma$ changes following the epoch. To facilitate the evaluation, Figure 7 provides MST distance curves for all binary convolution layers and training-validation accuracy curves in the entire learning process. In the first half-time, the $\\gamma$ is still significant, and the training focuses on MST distance optimization, while the accuracy optimization is temporarily less affected. Consequently, the MST distance of all binary convolutions is significantly down, especially for the deeper layers with more channels, while the training accuracy suddenly decreases and the validation accuracy goes down and strongly fluctuates at this time. In the second half-time, the training focuses on accuracy optimization with the lower $\\gamma$ value. Thus, the training accuracy tends to increase, while the validation accuracy rises, too, with a lower fluctuation. Although the MST distance also escalates again on all layers, these values are lower than at the initial time, especially on deeper layers. This is the reason why we can save computational costs by using this approach.", + "bbox": [ + 75, + 566, + 467, + 883 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Effect of hyper-parameter $\\lambda$ : The hyper-parameter $\\lambda$", + "bbox": [ + 96, + 885, + 467, + 900 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c8a4a7b419849b5c80518ae23408d7bd904294f01ab40ac5c33c96e40815e45f.jpg", + "image_caption": [ + "Figure 8. Number of parameters and MST depth on each convolution layer w.r.t. different $\\lambda$ values." + ], + "image_footnote": [], + "bbox": [ + 547, + 87, + 851, + 287 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "helps scale down the effect of the total MST distance to the new loss function. Each model has a different number of layers and channels that directly affects the total MST distance. Therefore, depending on the model, we adjust this hyper-parameter to balance the loss for accuracy and MST distance. In this section, the VGG-small model and CIFAR-10 dataset are used to estimate how the $\\lambda$ impacts the number of parameters, bit-operations, MST-depth, and accuracy with the range of $\\lambda$ from 1e-7 to 1e-5. Table 2 and Figure 8 provide the number of parameters, bit-operations, MST-depth, accuracy, and the number parameters for each binary convolution layer w.r.t different $\\lambda$ values. Accordingly, the number of parameters, bit-operations, and accuracy tend to be lower with higher $\\lambda$ values. However, the number of parameters/bit-ops is considerably reduced at $3.3\\times$ , while the accuracy degradation is acceptable with $2\\%$ when increasing the $\\lambda$ from 1e-7 to 1e-5. Besides, the MST depth also decreases when the $\\lambda$ value increases. Especially, when increasing $\\lambda$ from 1e-7 to 5e-7, the depth reduces $1.67\\times$ .", + "bbox": [ + 496, + 354, + 890, + 641 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.3. Comparison with SOTA methods", + "text_level": 1, + "bbox": [ + 500, + 650, + 790, + 666 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "To demonstrate the effectiveness of the proposed method, we perform a series of training experiments with various NN models on CIFAR-10, and ImageNet, then compare them with state-of-the-art methods. Specifically, for each NN model, we provide two experimental results corresponding to two cases 1) apply both the learning optimization in Sec. 4.2 and the MST reordering to the final training result (Ours 1); 2) directly apply the MST reordering to pretrained BNN models (Ours 2). In this paper, the pre-trained BNN models we use for fine-tuning and exploring the MST are provided by Xu et al. [33]. In terms of acceleration, a neural network model is fully trained on CIFAR-10 and implemented on an FPGA hardware platform to compare with recent hardware architectures.", + "bbox": [ + 496, + 674, + 890, + 883 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Software training comparison: For CIFAR-10, we", + "bbox": [ + 517, + 885, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "6097", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/b91144cd9f211e09b0293548d89a1a5e548afdc859dba744472f19d50a6f283e.jpg", + "table_caption": [], + "table_footnote": [ + "* Accuracy after fine-tuning is at https://github.com/z-hXu/ReCU [33]." + ], + "table_body": "
N-workMethod#Params (Mbit)#Bit-Ops (GOps)Top-1 Acc. (%)
VGG smallRAD[8]4.5710.60390.0
IR-Net[24]4.5710.60390.4
RBNN[20]4.5710.60391.3
Adabin[28]4.5710.60392.3
ReCU[33]4.5710.60392.4
SNN[32]3.0470.19491.0
Ours 1|20.556|1.6110.122|0.23291.5|93.3*
ResNet 18RAD[8]10.990.54790.5
IR-Net[24]10.990.54791.5
RBNN[20]10.990.54792.2
ReCU[33]10.990.54792.8
Adabin[28]10.990.54793.1
SNN[33]7.3240.28991.0
Ours 1|20.814|4.2930.104|0.21691.6|93.2*
ResNet 20DSQ[11]0.2670.04084.1
IR-Net[24]0.2670.04086.5
RBNN[20]0.2670.04086.5
ReCU[33]0.2670.04087.4
Adabin[28]0.2670.04088.2
SNN[32]0.1780.04085.1
Ours 1|20.096|0.1160.015|0.01786.5|88.0*
", + "bbox": [ + 80, + 88, + 465, + 368 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "conduct experiments on three neural BNN models: RestNet-18/20 and VGG-small. we compare our results with RAD [8], IR-Net [24], Adabin [28], ReCU [33], DSQ [11], and SNN [32]. Specifically, as shown in Table 3, when comparing Ours 1 with the highest-accuracy methods on all models, our proposed method reduces $8.2 \\times$ parameters and $4.9 \\times$ bit-Ops with a $0.97\\%$ accuracy drop on VGG-small. Meanwhile, when directly exploring the MST on the pre-trained models, Ours 2 gets $2.8 \\times$ parameters and $2.6 \\times$ bit-Ops reduction without accuracy degradation. On ResNet-18, Ours 1 gives $13.50 \\times$ parameters, $5.26 \\times$ bit-Ops reduction with a $1.29\\%$ accuracy drop, while Ours 2 reduces $2.6 \\times$ parameters and $2.5 \\times$ bit-Ops without compromising accuracy. Additionally, we have $2.78 \\times$ parameters, $2.67 \\times$ bit-Ops reduction, and a $1\\%$ accuracy drop with Ours 1; $2.3 \\times$ parameters, $2.35 \\times$ bit-Ops reduction and $0\\%$ accuracy drop on ResNet-20.", + "bbox": [ + 78, + 446, + 468, + 703 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Compared Ours 1 with the compression method SNN [32] on all models, the proposed method obtains a better compression ratio with a maximum reduction of $9.0 \\times$ parameters, $2.78 \\times$ bit-Ops on ResNet-18 while yielding higher accuracy and up to maximum $1.4\\%$ on ResNet-20. Meanwhile, with Our 2, we reduce maximum $1.89 \\times$ parameters on VGG-small, $2.35 \\times$ bit-Ops on ResNet-20, while achieving higher accuracy up to maximum $2.9\\%$ on ResNet-20.", + "bbox": [ + 78, + 704, + 467, + 838 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "For ImageNet, experiments are implemented on ResNet18/34 and comparison is performed with BNN+ [16], BiReal [23], XNOR++ [4], IR-Net [24], Adabin [28], ReCU [33], SNN [32]. According to Table 4, Ours 1 reduces $3.2 \\times$", + "bbox": [ + 80, + 840, + 467, + 898 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/8a2da48c78b5cea24be55378354969824779829817fd69abe402c0a5e2d32b67.jpg", + "table_caption": [ + "Table 3. Comparison with the state-of-the-art methods on CIFAR-10. The bit-width is 1 for both activation and weight." + ], + "table_footnote": [ + "* Accuracy after fine-tuning is at https://github.com/z-hXu/ReCU [33]." + ], + "table_body": "
N-workMethod#Params (Mbit)#Bit-Ops (GOps)Top-1 Acc. (%)
ResNet 18BNN+[16]10.991.67753.0
Bi-Real[23]10.991.67756.4
XNOR++[4]10.991.67757.1
IR-Net[24]10.991.67758.1
Adabin[28]10.991.67763.1
ReCU[33]10.991.67761.0
SNN[32]7.320.88356.3
Ours 1|23.43|4.840.636|0.71657.0|61.2*
ResNet 34Bi-Real[23]21.093.52662.2
IR-Net[24]21.093.52662.9
Adabin[28]21.093.52666.4
ReCU[33]21.093.52665.1
SNN[32]14.061.69661.4
Ours 1|29.44|9.511.550|1.55862.9|65.4*
", + "bbox": [ + 504, + 88, + 887, + 282 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 4. Comparison with the state-of-the-art methods on ImageNet. The bit-width is 1 for both activation and weight.", + "bbox": [ + 503, + 309, + 888, + 335 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "parameters, $2.6 \\times$ bit-Ops on ResNet-18; and $2.23 \\times$ parameters, $2.27 \\times$ bit-Ops on ResNet-34, compared to the baseline [33], while the accuracy degradation is $4\\%$ and $2.2\\%$ on ResNet18 and ResNet-34, respectively. Ours 2 achieves $2.27 \\times$ parameters, $2.34 \\times$ bit-Ops reduction on ResNet-18; and $2.2 \\times$ parameters, $2.26 \\times$ bit-Ops reduction without accuracy drop. Compared to SNN with the highest compression ratio recently, our proposed method with Ours 1 saves $2.13 \\times$ parameters and $1.3 \\times$ bit-Ops on ResNet-18, $1.49 \\times$ parameters and $1.09 \\times$ bit-Ops on ResNet-34, while the trained models give higher accuracy of $0.7\\%$ and $1.5\\%$ on ResNet-18, ResNet-34, respectively. Meanwhile, Ours 2 without accuracy drop saves up to $1.51 / 1.47 \\times$ parameters and $1.23 / 1.08 \\times$ bit-Ops on ResNet-18/34, respectively.", + "bbox": [ + 503, + 362, + 888, + 573 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Hardware implementation comparison: Table 5 provides the hardware performance comparison with previous works using CIFAR-10 for the training. We compare the proposed architecture with FINN [30], FINN-R [3] from Xilinx, ReBNet [10] and the design in [31]. Accordingly, the proposed accelerator takes the leading place in both speed and area efficiency (FPS/LUTs). More specifically, it performs $1.6 \\times$ faster than the fastest previous work (FINN), while obtaining $3.7 \\times$ area efficiency with a little higher accuracy. In addition, compared to [31], our method gains over $1.81 \\times$ area efficiency. Besides, to compare our method with the K-mean approach, we implement another design from the same training result with the K-mean method. According to Table 5, our method performs better $1.25 \\times$ in terms of resources and area efficiency.", + "bbox": [ + 503, + 574, + 888, + 799 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 503, + 815, + 616, + 829 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In conclusion, this paper introduces a comprehensive method for compressing BNNs, which covers the entire process from learning to hardware implementation. By utilizing the minimum spanning tree (MST), we effectively re", + "bbox": [ + 503, + 840, + 888, + 898 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "6098", + "bbox": [ + 483, + 946, + 513, + 955 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/605662c57c26d4ba2a2731a211c3012b906f1d01143def223e2466bd63b9138d.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
DesignFreq (MHz)LUTsAcc. (%)FPS (K)FPS/ LUTs
FINN[30]20046,25380.1220.47
FINN[30]125365,96380.11280.35
FINN-R[3]237332,63780.11050.31
FINN-R[3]30041,73380.1200.48
FINN[3]30025,43180.11.90.07
ReBNet[10]20053,20080.660.11
[31]210290,01280.22050.70
Ours (K-mean)210201,43480.52051.01
Ours (MST)210161,29480.52051.27
", + "bbox": [ + 96, + 88, + 450, + 223 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 5. Hardware performance comparison with the state-of-the-art architectures on CIFAR-10.", + "bbox": [ + 76, + 233, + 468, + 261 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "duce the computation cost of binary convolution calculation. To optimize the MST during the training stage, a learning algorithm is proposed. Moreover, we present a hardware implementation for the inference task. Our experimental results demonstrate that the proposed method significantly reduces computation costs while maintaining high accuracy, making it promising for practical applications.", + "bbox": [ + 75, + 276, + 468, + 383 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "7. Acknowledgements", + "text_level": 1, + "bbox": [ + 76, + 398, + 264, + 416 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work was supported by the NRF grant funded by the Korea government(MSIT) (No. RS-2023-00207816), and part by IITP Grant funded by MSIT (Artificial Intelligence Innovation Hub) under Grant 2021-0-02068, (No. RS-2022-00155911, AI Convergence Innovation Human Resources Development (Kyung Hee University)), IITP No.2019-0-01287, Evolvable Deep Learning Model Generation Platform for Edge Computing and ITRC support program (IITP-2023-RS-2023-00258649).", + "bbox": [ + 75, + 422, + 468, + 559 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 76, + 575, + 173, + 590 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Richard Bellman. Dynamic programming treatment of the travelling salesman problem. Journal of the ACM (JACM), 9(1):61-63, 1962. 2, 5", + "[2] Yoshua Bengio, Nicholas Léonard, and Aaron Courville. Estimating or propagating gradients through stochastic neurons for conditional computation. arXiv preprint arXiv:1308.3432, 2013. 3", + "[3] Michaela Blott, Thomas B Preußer, Nicholas J Fraser, Giulio Gambardella, Kenneth O'brien, Yaman Umuroglu, Miriam Leeser, and Kees Vissers. Finn-r: An end-to-end deep-learning framework for fast exploration of quantized neural networks. ACM Transactions on Reconfigurable Technology and Systems (TRETS), 11(3):1-23, 2018. 2, 8, 9", + "[4] Adrian Bulat and Georgios Tzimiropoulos. Xnornet++: Improved binary neural networks. arXiv preprint arXiv:1909.13863, 2019. 1, 3, 8", + "[5] Zhaowei Cai, Xiaodong He, Jian Sun, and Nuno Vasconcelos. Deep learning with low precision by half-wave gaussian quantization. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5918-5926, 2017. 2" + ], + "bbox": [ + 86, + 602, + 468, + 898 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[6] Yu-Hsin Chen, Tushar Krishna, Joel S Emer, and Vivienne Sze. Eyeriss: An energy-efficient reconfigurable accelerator for deep convolutional neural networks. IEEE journal of solid-state circuits, 52(1):127-138, 2016. 1", + "[7] Matthieu Courbariaux, Itay Hubara, Daniel Soudry, Ran El-Yaniv, and Yoshua Bengio. Binarized neural networks: Training deep neural networks with weights and activations constrained to + 1 or -1. arXiv preprint arXiv:1602.02830, 2016. 1, 2", + "[8] Ruizhou Ding, Ting-Wu Chin, Zeye Liu, and Diana Marculescu. Regularizing activation distribution for training binarized deep networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 11408-11417, 2019. 8", + "[9] Cheng Fu, Shilin Zhu, Hao Su, Ching-En Lee, and Jishen Zhao. Towards fast and energy-efficient binarized neural network inference on fpga. arXiv preprint arXiv:1810.02068, 2018. 1, 2, 3, 4", + "[10] Mohammad Ghasemzadeh, Mohammad Samragh, and Farinaz Koushanfar. Rebnet: Residual binarized neural network. In 2018 IEEE 26th annual international symposium on field-programmable custom computing machines (FCCM), pages 57-64. IEEE, 2018. 2, 8, 9", + "[11] Ruihao Gong, Xianglong Liu, Shenghu Jiang, Tianxiang Li, Peng Hu, Jiazhen Lin, Fengwei Yu, and Junjie Yan. Differentiable soft quantization: Bridging full-precision and low-bit neural networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4852–4861, 2019. 8", + "[12] Song Han, Huizi Mao, and William J Dally. Deep compression: Compressing deep neural networks with pruning, trained quantization and huffman coding. arXiv preprint arXiv:1510.00149, 2015. 1", + "[13] John A Hartigan and Manchek A Wong. Algorithm as 136: A k-means clustering algorithm. Journal of the royal statistical society. series c (applied statistics), 28(1):100-108, 1979. 2, 4", + "[14] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 1, 2, 5", + "[15] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, et al. Distilling the knowledge in a neural network. arXiv preprint arXiv:1503.02531, 2(7), 2015. 1", + "[16] Itay Hubara, Matthieu Courbariaux, Daniel Soudry, Ran El-Yaniv, and Yoshua Bengio. Binarized neural networks. Advances in neural information processing systems, 29, 2016. 8", + "[17] Hyeonuk Kim, Jaehyeong Sim, Yeongjae Choi, and Lee-Sup Kim. A kernel decomposition architecture for binary-weight convolutional neural networks. In Proceedings of the 54th Annual Design Automation Conference 2017, pages 1-6, 2017. 1, 3", + "[18] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images. 2009. 2", + "[19] Dongsoo Lee, Se Jung Kwon, Byeongwook Kim, Yongkwon Jeon, Baeseong Park, and Jeongin Yun. Flexor: Train" + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "6099", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "able fractional quantization. Advances in neural information processing systems, 33:1311-1321, 2020. 3", + "[20] Mingbao Lin, Rongrong Ji, Zihan Xu, Baochang Zhang, Yan Wang, Yongjian Wu, Feiyue Huang, and Chia-Wen Lin. Rotated binary neural network. Advances in neural information processing systems, 33:7474-7485, 2020. 1, 3, 8", + "[21] Xiaofan Lin, Cong Zhao, and Wei Pan. Towards accurate binary convolutional neural network. Advances in neural information processing systems, 30, 2017. 3", + "[22] Zechun Liu, Zhiqiang Shen, Marios Savvides, and Kwang-Ting Cheng. Reactnet: Towards precise binary neural network with generalized activation functions. In European conference on computer vision, pages 143-159. Springer, 2020. 1, 3", + "[23] Zechun Liu, Baoyuan Wu, Wenhan Luo, Xin Yang, Wei Liu, and Kwang-Ting Cheng. Bi-real net: Enhancing the performance of 1-bit cnns with improved representational capability and advanced training algorithm. In Proceedings of the European conference on computer vision (ECCV), pages 722-737, 2018. 1, 3, 8", + "[24] Haotong Qin, Ruihao Gong, Xianglong Liu, Mingzhu Shen, Ziran Wei, Fengwei Yu, and Jingkuan Song. Forward and backward information retention for accurate binary neural networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2250-2259, 2020. 3, 8", + "[25] Mohammad Rastegari, Vicente Ordonez, Joseph Redmon, and Ali Farhadi. Xnor-net: Imagenet classification using binary convolutional neural networks. In European conference on computer vision, pages 525-542. Springer, 2016. 1, 3", + "[26] Olga Russakovsky, Jia Deng, Hao Su, Jonathan Krause, Sanjeev Satheesh, Sean Ma, Zhiheng Huang, Andrej Karpathy, Aditya Khosla, Michael Bernstein, et al. Imagenet large scale visual recognition challenge. International journal of computer vision, 115(3):211-252, 2015. 2", + "[27] Mark Sandler, Andrew Howard, Menglong Zhu, Andrey Zh-moginov, and Liang-Chieh Chen. Mobilenetv2: Inverted residuals and linear bottlenecks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4510-4520, 2018. 1", + "[28] Zhijun Tu, Xinghao Chen, Pengju Ren, and Yunhe Wang. Adabin: Improving binary neural networks with adaptive binary sets. In European Conference on Computer Vision, pages 379-395. Springer, 2022. 3, 8", + "[29] William Thomas Tutte and William Thomas Tutte. Graph theory, volume 21. Cambridge university press, 2001. 4", + "[30] Yaman Umuroglu, Nicholas J Fraser, Giulio Gambardella, Michaela Blott, Philip Leong, Magnus Jahre, and Kees Vissers. Finn: A framework for fast, scalable binarized neural network inference. In Proceedings of the 2017 ACM/SIGDA international symposium on field-programmable gate arrays, pages 65-74, 2017. 1, 2, 8, 9", + "[31] Quang Hieu Vo, Ngoc Linh Le, Faaiz Asim, Lok-Won Kim, and Choong Seon Hong. A deep learning accelerator based on a streaming architecture for binary neural networks. IEEE Access, 10:21141-21159, 2022. 1, 2, 3, 4, 5, 6, 8, 9", + "[32] Yikai Wang, Yi Yang, Fuchun Sun, and Anbang Yao. Sub-bit neural networks: Learning to compress and accelerate binary" + ], + "bbox": [ + 78, + 90, + 468, + 901 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "neural networks. In International Conference on Computer Vision (ICCV), 2021. 1, 2, 3, 8", + "[33] Zihan Xu, Mingbao Lin, Jianzhuang Liu, Jie Chen, Ling Shao, Yue Gao, Yonghong Tian, and Rongrong Ji. Recu: Reviving the dead weights in binary neural networks. In Proceedings of the IEEE/CVF international conference on computer vision, pages 5198-5208, 2021. 1, 2, 3, 5, 6, 7, 8" + ], + "bbox": [ + 501, + 92, + 890, + 190 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "6100", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/9bf308bf-7020-43ef-9313-33d2e81da894_model.json b/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/9bf308bf-7020-43ef-9313-33d2e81da894_model.json new file mode 100644 index 0000000000000000000000000000000000000000..c76017094614f6fcb946efb035684ec77ae61d37 --- /dev/null +++ b/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/9bf308bf-7020-43ef-9313-33d2e81da894_model.json @@ -0,0 +1,1892 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.107, + 0.13, + 0.868, + 0.178 + ], + "angle": 0, + "content": "MST-compression: Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree" + }, + { + "type": "text", + "bbox": [ + 0.155, + 0.204, + 0.821, + 0.24 + ], + "angle": 0, + "content": "Quang Hieu Vo, Linh-Tam Tran, Sung-Ho Bae, Lok-Won Kim, Choong Seon Hong* \nDepartment of Computer Science and Engineering, Kyung Hee University" + }, + { + "type": "text", + "bbox": [ + 0.268, + 0.242, + 0.702, + 0.256 + ], + "angle": 0, + "content": "{2019310178, tamlt, shbae, lwk, cshong}@khu.ac.kr" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.292, + 0.314, + 0.308 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.324, + 0.474, + 0.718 + ], + "angle": 0, + "content": "Binary neural networks (BNNs) have been widely adopted to reduce the computational cost and memory storage on edge-computing devices by using one-bit representation for activations and weights. However, as neural networks become wider/deeper to improve accuracy and meet practical requirements, the computational burden remains a significant challenge even on the binary version. To address these issues, this paper proposes a novel method called Minimum Spanning Tree (MST) compression that learns to compress and accelerate BNNs. The proposed architecture leverages an observation from previous works that an output channel in a binary convolution can be computed using another output channel and XNOR operations with weights that differ from the weights of the reused channel. We first construct a fully connected graph with vertices corresponding to output channels, where the distance between two vertices is the number of different values between the weight sets used for these outputs. Then, the MST of the graph with the minimum depth is proposed to reorder output calculations, aiming to reduce computational cost and latency. Moreover, we propose a new learning algorithm to reduce the total MST distance during training. Experimental results on benchmark models demonstrate that our method achieves significant compression ratios with negligible accuracy drops, making it a promising approach for resource-constrained edge-computing devices." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.746, + 0.21, + 0.761 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.772, + 0.47, + 0.879 + ], + "angle": 0, + "content": "Deep Neural Networks (DNNs) have been widely applied in many artificial intelligence applications, especially vision tasks with high accuracy [27, 14]. However, the cost of computation and massive storage burden is significantly challenging to deploy DNNs on embedded systems such as mobile devices and other resource-constrained platforms. Many approaches have been proposed and demonstrated" + }, + { + "type": "image", + "bbox": [ + 0.578, + 0.288, + 0.707, + 0.422 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.739, + 0.289, + 0.811, + 0.422 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.439, + 0.895, + 0.495 + ], + "angle": 0, + "content": "Figure 1. Illustration of kernel compression for BNNs with the Kmean method (a) and the shortest Hamiltonian path (b), in which adding red connections can further reduce the computational cost for both of them." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.505, + 0.892, + 0.612 + ], + "angle": 0, + "content": "their effectiveness in reducing energy and resources while maintaining the deep models' accuracy, including pruning [12], quantization [7], distillation [15], and efficient hardware implementation [6]. Among these methods, quantization with less bit-width for parameter and activation representation is widely used due to its great benefits and possibility in most practical applications." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.612, + 0.893, + 0.809 + ], + "angle": 0, + "content": "Binarized neural network is a particular form of the quantization method in which weight values and activations are converted to 1-bit values. Accordingly, multiplications and accumulation operations can be replaced by XNOR and Popcount operations [7], respectively. In addition, batch normalization is simplified to a threshold comparison [31], while the pooling can be performed with OR operations [30]. Consequently, the compression ratio on memory storage and computational cost is significantly improved, leading to remarkable performance acceleration. Nevertheless, the accuracy degradation is the trade-off of minimizing the bit-width as BNN. Thus, most previous works focus on reducing this accuracy gap [25, 4, 33, 22, 20, 33, 23]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.895, + 0.902 + ], + "angle": 0, + "content": "Meanwhile, compressing BNNs has not received much attention, with only a few prominent methods [32, 9, 31, 17], where the kernel compression [9, 31] gives impressive results with roughly \\(50\\%\\) resources reduction. In particular, given a binary convolution, inspired by an observation that an output channel can be calculated using another out" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.225, + 0.9 + ], + "angle": 0, + "content": "*Corresponding Author" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.958 + ], + "angle": 0, + "content": "6091" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.468 + ], + "angle": 0, + "content": "put channel and outputs of XNOR operations using weights that respectively differ from the reused channel's weights [9], authors in [31, 9] proposed to construct a fully connected graph, in which each vertex corresponds to an output channel, and distance between two vertices is the number of different values between two weight sets used for the two output channels. Then, based on the graph, they use the K-mean cluster and shortest Hamiltonian path to reorder the convolution output calculation, aiming to reduce the number of XNOR operations. However, these approaches have yet to fully minimize the computational cost as output channels can use less computation. Indeed, Figure 1 (a) illustrates an example of the K-mean method, where two vertices are considered centers of two groups. Two output channels corresponding to centers are fully calculated1, while other vertices reuse their centers for calculation. However, adding a connection between the two centers would enable one to utilize the rest with less computation cost. Additionally, in the shortest Hamiltonian path shown in Figure 1 (b), there may exist a connection to a specific vertex that is shorter than the connection from the preceding vertex in the path, leading to a lower required number of operations for this vertex. Furthermore, time complexity poses a challenge in these methods [1, 13], resulting in longer exploration times." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.469, + 0.473, + 0.697 + ], + "angle": 0, + "content": "To more effectively minimize the number of XNOR operations with the mentioned observation, in all connections to a specific vertex, the minimum connection must be selected to minimize the computation cost for this vertex. In addition, all of these selected connections must be included in a subgraph that visits all vertices exactly once to ensure that only one output channel is fully calculated. As a result, a MST is the only structure that can fulfill these requirements. Therefore, this paper leverages the MST to reorder binary convolution output calculations. Figure 2 shows a simple example of reordering calculation on a convolution. In this example, only the output channel 4 is fully calculated with \\( C_{in} \\times M \\times M \\) bit-weight values. In contrast, other channels are calculated using output channel 4, following the MST direction." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.697, + 0.473, + 0.849 + ], + "angle": 0, + "content": "On the other hand, to maximize the advantages of the MST, we further minimize the MST distance of all convolution layers with a new learning algorithm right during the training stage. Besides, we propose a hardware accelerator for BNNs applying the MST compression to demonstrate the feasibility and effectiveness of the method related to hardware resources. To the best of our knowledge, this method gives the highest compression ratio with implementation from learning for compression to acceleration. In summary, the following are contributions of this paper:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.861, + 0.471, + 0.877 + ], + "angle": 0, + "content": "- We introduce and analyze the effectiveness of the MST" + }, + { + "type": "image", + "bbox": [ + 0.514, + 0.09, + 0.891, + 0.241 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.257, + 0.895, + 0.314 + ], + "angle": 0, + "content": "Figure 2. The process of arranging the order of computation on a binary convolution layer, in which output channel 4 is fully calculated first. Then, the output channel 4 is used to calculate channel 1, channel 2 and channel 3." + }, + { + "type": "text", + "bbox": [ + 0.531, + 0.339, + 0.892, + 0.369 + ], + "angle": 0, + "content": "in reducing the computational cost for the inference on a binary convolution layer." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.38, + 0.892, + 0.442 + ], + "angle": 0, + "content": "- We propose a training algorithm that can reduce the MST distance and depth right during the training process, which consequently maximizes the compression ratio for inference implementation." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.453, + 0.892, + 0.513 + ], + "angle": 0, + "content": "- We provide the corresponding hardware acceleration for the proposed method with high throughput and better resource efficiency, compared to related works [3, 30, 31, 10]." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.38, + 0.892, + 0.513 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.528, + 0.892, + 0.74 + ], + "angle": 0, + "content": "The experiments are performed for BNNs including VGG-small [5], ResNet-18/20 [14] on CIFAR-10 dataset [18], and ResNet-18/34 [14] on ImageNet [26]. The results show that the proposed approach gives a higher compression ratio than the previous works [32]. Compared to the baseline [33], our method reduces up to \\( 13.5 \\times \\) the convolution parameters and \\( 5.51 \\times \\) bit-wise operations on the same model with an acceptable accuracy degradation. Regarding hardware acceleration, we conduct the experiments for a BNN with the same structure as the baseline [31] and apply the proposed approach. Compared to the baseline [31], hardware deployments demonstrate that BNNs with our method save \\( 1.8 \\times \\) LUTs, and \\( 1.81 \\times \\) area efficiency while maintaining the acceleration speed and accuracy." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.755, + 0.642, + 0.77 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Training neural networks with binary weights and activations were first introduced by Coubariaux et al. [7] and then rapidly gained attention from the community due to the high compression ratio. However, accuracy drop is a critical problem of this direction, while compression is still highly demanded. Various techniques are proposed to further compress and improve accuracy based on the binary property." + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.432, + 0.901 + ], + "angle": 0, + "content": "\\( {}^{1} \\) calculated with \\( {C}_{in} \\times M \\times M \\) XNORs,denoted in Figure 2" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6092" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.455 + ], + "angle": 0, + "content": "For accuracy improvement, Rastegari et al. [25] proposed adding a scaling factor to the convolution to reduce the quantization error. To generalize this idea aiming to enhance accuracy, the authors in [4] extended this factor dimension and enabled its training option as a learnable parameter. Besides, instead of using the Straight Through Estimation (STE) method [2], Liu et al. [23], and Lin et al. [20] proposed using a piece-wise linear and training-aware approximation function, respectively, to approximate the sign function gradient better. Meanwhile, some previous works introduced both new optimization techniques and corresponding BNN to shrink the accuracy gap entirely [22, 21, 28, 24]. For example, based on Bi-real Net in [23], authors in [22] proposed new sign and activation functions to shift and reshape activation distribution with a new baseline neural network model that can boost the performance. Other works look at the binary characteristics from deeper perspectives to limit information loss [20, 28, 33]. For example, KL divergence is employed in [28] to minimize the difference between the distribution of binary and real-weight counterparts. Xu et al. [33] observed the low probability of changing large full-precision weight when binarizing and proposed the ReCu function to revive the death weights, leading to lower quantization error." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.46, + 0.473, + 0.688 + ], + "angle": 0, + "content": "Binary model compression has received less attention as only a few techniques have been proposed so far. Specifically, Lee et al. [19] proposed an encryption algorithm to compress binary weights with lower than 1-bit per weight, and XOR-gate networks are used to decrypt the inference task. Similarly, Sub-bit Neural Networks (SNN) [32] proposed using lower than 9 bits for each \\(3 \\times 3\\) binary kernel based on the scattered 9-bit kernel distribution. Other proposed compression methods provided only hardware techniques for inference implementation. Authors in [31, 9] proposed BNN hardware architectures using weight/input reuse with different calculation orders for convolution to reduce hardware overhead. Kim et al. [17] introduces kernel decomposition that can reduce the computational cost by sharing one base output for all channels." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.718, + 0.206, + 0.736 + ], + "angle": 0, + "content": "3. Background" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.75, + 0.473, + 0.904 + ], + "angle": 0, + "content": "This section briefly describes how to construct a binary convolution layer and the related optimization methods. For a convolution layer with \\( C_{in} \\) input channels, \\( C_{out} \\) output channels, and kernel size \\( M \\), weights and activations are denoted by \\( \\mathcal{W}^r \\in \\mathbb{R}^n \\) and \\( A^r \\in \\mathbb{R}^m \\), where \\( n = C_{out} \\times C_{in} \\times M \\times M \\) and \\( m = C_{in} \\times W_{in} \\times H_{in} \\). \\( W_{in} \\times H_{in} \\) represents input feature map size. To simplify the computation and reduce memory storage, in a binary convolution layer, the binarization of activations \\( \\mathcal{A}^b \\in \\{\\pm 1\\}^m \\) and weights \\( \\mathcal{W}^b \\in \\{\\pm 1\\}^n \\) is acquired by the fol" + }, + { + "type": "image", + "bbox": [ + 0.513, + 0.092, + 0.887, + 0.316 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.334, + 0.895, + 0.391 + ], + "angle": 0, + "content": "Figure 3. Weight-reuse method description. Here, the red line is counting the number of elements, the green line is summing all elements. \\( P_{12} \\) is \\( \\sum_{j=1}^{d_{12}} \\mathrm{XNOR}(\\mathcal{A}_{2j}, \\mathcal{W}_{2j}) \\), and \\( Y_{2} \\) is \\( 2(P_{1} - d_{12} + 2P_{12}) - C_{in} \\times M \\times M \\)." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.399, + 0.678, + 0.414 + ], + "angle": 0, + "content": "lowing sign function [25]," + }, + { + "type": "equation", + "bbox": [ + 0.571, + 0.421, + 0.892, + 0.462 + ], + "angle": 0, + "content": "\\[\nx ^ {b} = \\operatorname {S i g n} (x) = \\left\\{ \\begin{array}{l} + 1, \\text {i f} x \\geq 0, \\\\ - 1, \\text {o t h e r w i s e .} \\end{array} \\right. \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.47, + 0.895, + 0.517 + ], + "angle": 0, + "content": "If \\(-1\\) is substituted by 0 to represent a negative value for \\(\\mathcal{A}^b\\) and \\(\\mathcal{W}^b\\), the output convolution operation of the \\(i^{th}\\) channel now is reformulated as in Eq. (2) [31]." + }, + { + "type": "equation", + "bbox": [ + 0.5, + 0.524, + 0.892, + 0.58 + ], + "angle": 0, + "content": "\\[\nY _ {i} = (2 \\sum_ {j = 1} ^ {C _ {i n} M M} \\operatorname {X N O R} \\left(\\mathcal {A} _ {i j} ^ {b}, \\mathcal {W} _ {i j} ^ {b}\\right) - C _ {i n} \\times M \\times M) \\odot \\alpha , \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.578, + 0.895, + 0.732 + ], + "angle": 0, + "content": "where \\(\\sum_{1}^{C_{in}\\times M\\times M}\\mathrm{XNOR}(\\mathcal{A}_{ij}^{b},\\mathcal{W}_{ij}^{b})\\) is the number of set-bits (Popcount) of the output channel \\(i^{th}\\), \\(\\odot\\) is the element-wise multiplication, and \\(C_{in}\\times M\\times M\\) is the number of bit-wise XNOR operations used to calculate one output channel. The scaling factor \\(\\alpha\\) is added as a learnable parameter to lessen quantization error [25]. For backward propagation, following [23], the STE [2] method is used for the approximation gradient on weights, while the piecewise polynomial function [23] is used for gradient approximation on activations." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.733, + 0.895, + 0.903 + ], + "angle": 0, + "content": "To further compress the BNN models, in this paper, we apply the weight reuse method [31] for the inference task. Accordingly, given the \\( l^{th} \\) binary convolution, as shown in Figure 3, we denote \\( P_{i} \\) and \\( P_{j} \\) as the output of the Popcount operations of the output channels \\( i^{th} \\) and \\( j^{th} \\), respectively. All binary weights of the layer are divided into \\( C_{out} \\) weight sets \\( w_{b}^{li} \\in \\{\\pm 1\\}^{C_{in} \\times M \\times M} \\), where \\( i = 1,2,\\dots,C_{out} \\) and each weight set is used to calculate for an output channel. \\( d_{ij} \\) is the number of weight bits in the \\( w_{b}^{li} \\) that differ from the \\( w_{b}^{lj} \\), compared one-to-one respectively. \\( P_{ij} \\) is the sum of XNOR operations with the" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6093" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.09, + 0.468, + 0.528 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.542, + 0.473, + 0.626 + ], + "angle": 0, + "content": "Figure 4. Comparison between the computation process of a standard binary convolution and our method in BNN acceleration. Instead of fully computing all \\( C_{in} \\times M \\times M \\) XNOR operations for each layer, our method provides an optimal order of the calculation using the MST to minimize the number of XNOR operations and total parameters." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.63, + 0.472, + 0.678 + ], + "angle": 0, + "content": "weights of the channel \\( j^{th} \\) that differ from the \\( i^{th} \\) counterpart. To calculate the output channel \\( j^{th} \\) from the output channel \\( i^{th} \\), we use Eq. (3)." + }, + { + "type": "equation", + "bbox": [ + 0.126, + 0.688, + 0.47, + 0.706 + ], + "angle": 0, + "content": "\\[\nY _ {j} = 2 \\left(P _ {i} - d _ {i j} + 2 P _ {i j}\\right) - C _ {i n} \\times M \\times M. \\tag {3}\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.717, + 0.214, + 0.734 + ], + "angle": 0, + "content": "4. Methodology" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.742, + 0.47, + 0.759 + ], + "angle": 0, + "content": "4.1. Minimum Spanning Tree for BNN Acceleration" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.901 + ], + "angle": 0, + "content": "For a binary convolution layer, we construct a fully connected graph in which each vertex corresponds to an output channel. The distance between two vertices \\(i\\) and \\(j\\) is \\(d_{ij}\\). As shown in Eq. (3), an output channel \\(j\\) can be calculated via the Popcount of an output channel \\(i\\) and the Popcount of \\(d_{ij}\\) XNOR operations. That means the number of XNOR operations executed for the output channel \\(j\\) is the distance \\(d_{ij}\\). Based on this observation, to minimize the number of XNOR operations used for all out" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.895, + 0.304 + ], + "angle": 0, + "content": "put channels, we need a sub-graph that includes all vertices with the minimum total edge distances, which is named an MST [29]. Returning to the example in Figure 2, Figure 4 illustrates the computation process of this convolution example with the standard and proposed approach. Specifically, in the standard direction, each output channel needs 9 XNOR operations, while in our direction, only the \\(4^{th}\\) output channel is fully computed by 9 XNOR operations, and the \\(1^{st}, 2^{nd}, 3^{rd}\\) output channels reuse the output channel \\(4^{th}\\) with 2, 3, 2 XNOR operations, respectively. Accordingly, the compression ratio for this example is \\((2 + 3 + 2 + 3 \\times 3) / (4 \\times 1 \\times 3 \\times 3) = 0.44\\). In general, we can reduce the computational cost for a convolution layer with the following ratio:" + }, + { + "type": "equation", + "bbox": [ + 0.57, + 0.311, + 0.892, + 0.35 + ], + "angle": 0, + "content": "\\[\n\\mathcal {R} = \\frac {\\sum_ {j \\neq r o o t} ^ {C _ {o u t}} d _ {i j} + C _ {i n} \\times M \\times M}{C _ {o u t} \\times C _ {i n} \\times M \\times M}, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.356, + 0.892, + 0.386 + ], + "angle": 0, + "content": "where \\(i\\) is the parent of the vertex \\(j\\). If \\(j\\) is the root of the MST, this output uses \\(C_{in} \\times M \\times M\\) binary weight values." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.387, + 0.892, + 0.492 + ], + "angle": 0, + "content": "Regarding parameters, because the streaming architecture described in Sec. 4.3 is fully implemented with all layers on the FPGA platform, weights' locations can be converted to connections from inputs to the correct XNORs and corresponding weight values at the circuit level. Thus, our proposed method counts only the parameters we need for XNOR logic gates, as shown in Figure 4." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.492, + 0.892, + 0.598 + ], + "angle": 0, + "content": "Number of bit-wise operations. Compared with the previous approaches [31, 9], in a binary convolution layer, the proposed method can better reduce the number of XNORs and parameters. Firstly, as explained in the previous section, adding connections among centers leads to less computation for the K-mean approach [31] as in Eq. (5)." + }, + { + "type": "equation", + "bbox": [ + 0.508, + 0.603, + 0.892, + 0.637 + ], + "angle": 0, + "content": "\\[\n\\sum_ {j} d _ {i j} + C _ {i n} \\times M \\times M < \\sum_ {j \\notin C} d _ {i j} + R \\times C _ {i n} \\times M \\times M, \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.644, + 0.892, + 0.795 + ], + "angle": 0, + "content": "where \\( C \\) includes all centers, \\( R \\) is the number of centers. Furthermore, adding connections among centers also creates a spanning tree, whose computational cost is always equal to or higher than using an MST. Secondly, in [9], the authors proposed using the shortest Hamiltonian path to arrange the computation order. Because this path visits all vertices exactly once, the shortest Hamiltonian path is also a spanning tree. Therefore, the number of XNOR bit-wise operations using an MST method is equal to or lower than the shortest Hamiltonian path." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Exploration time. The MST is faster and less complex for finding the computation order, compared to previous work [9, 31]. Indeed, the MST is found by Prim's algorithm with the complexity of \\( O(V^2) \\) [29], where \\( V \\) is the number of vertices. In contrast, the K-mean algorithm requires \\( O(V^2 G) \\) [13] time complexity, where \\( G \\) denotes the number of groups. Since the optimal number of groups varies" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6094" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.117, + 0.089, + 0.434, + 0.259 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.27, + 0.473, + 0.314 + ], + "angle": 0, + "content": "Figure 5. a) The computation tree's depth using the K-mean cluster. b) The computation tree's depth using the shortest Hamiltonian path. c) The computation tree's depth using the MST." + }, + { + "type": "table", + "bbox": [ + 0.084, + 0.326, + 0.465, + 0.426 + ], + "angle": 0, + "content": "
LHamiltonianK-meanMST
Bit-OpsTimeBit-OpsTimeBit-OpsTime
11.08 M31.3 s1.33 M0.090 s1.07 M0.021 s
21.09 M32.9 s1.30 M0.075 s1.06 M0.021 s
31.07 M32.6 s1.30 M0.085 s1.05 M0.023 s
41.10 M32.7 s1.33 M0.076 s1.08 M0.021 s
51.11 M32.5 s1.32 M0.115 s1.09 M0.020 s
61.09 M32.5 s1.33 M0.086 s1.08 M0.021 s
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.435, + 0.472, + 0.478 + ], + "angle": 0, + "content": "Table 1. Bit-Ops and running time w.r.t. different approaches for reordering calculation on the first 6 convolution layers of ResNet20 with 16 output channels." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.493, + 0.47, + 0.674 + ], + "angle": 0, + "content": "across convolutions, extra time is needed to determine this number for each case. Meanwhile, the shortest Hamiltonian path has a much higher time complexity of \\( O(V^{2}2^{V}) \\) [1], making it challenging to apply in practical settings. To estimate these approaches for practical operation, we perform experiments for the first 6 binary convolution layers of ResNet-20 [14] with the weight data trained by [33], while experiments on deeper layers with a larger number of output channels are infeasible even uncompleted for the K-mean and the shortest Hamiltonian path approach due to their longer running times. According to Table 1, the MST approach gives the lowest bit-Ops and exploration time." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.675, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Computation latency. This is one of the factors affecting the resource overhead. This paper focuses on improving the architecture in [31], a streaming acceleration for BNNs. In doing so, the deeper the computation tree, the longer latency between the time output of the first and the last channel comes out. Consequently, the number of added registers (Flip-flops) for synchronization tends to be equal or more for the deeper tree because all output channels must be available at the same clock for the next convolution operation. The exact number of added registers depends on the number of adders executed in a clock period, which is affected by the required frequency, design complexity, and hardware platform. Thus, to evaluate the comprehensive effects of the depth with practical implementations, the experiments related to this comparison are provided in Sec. 5." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.895, + 0.289 + ], + "angle": 0, + "content": "Figure 5 visually describes the depth of the MST, K-mean cluster, and the shortest Hamiltonian path approach. Accordingly, the depths of the K-mean method and the shortest Hamiltonian path are always 1 and \\(V\\), respectively. Meanwhile, the MST's depth can range from 1 to \\(V\\), depending on the graph structure. Therefore, the proposed method is always better than the shortest Hamiltonian path in all aspects (number of operations, latency, running time). Meanwhile, the K-mean method gives a better latency but much worse for the rest. After exploring an MST for the posttraining stage to limit the impact of the tree depth on latency and resources, we continue finding a new root that makes the depth of the new tree minimum." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.297, + 0.715, + 0.314 + ], + "angle": 0, + "content": "4.2. Learning Optimization" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.321, + 0.895, + 0.518 + ], + "angle": 0, + "content": "According to the observation mentioned earlier, to enhance the benefits of the MST approach, we propose a simple learning method that can further reduce the MST depth and total MST distance over a BNN model. Specifically, to make the training converged, instead of directly optimizing the MST, we cluster weight sets \\((\\mathrm{w}_b^{li})\\) to different groups and try to reduce the distance among weight sets in each group by optimizing the distances from all weight sets to fixed centers. In doing so, given the \\(l^{th}\\) binary convolution layer of a BNN model, we first randomly sample a binary center subset \\(\\mathbb{C}_l \\subset \\{\\pm 1\\}^{C_{in} \\times M \\times M}\\) and \\(|\\mathbb{C}_l| = N_l\\). Then, we explore the nearest center in \\(\\mathbb{C}_l\\) for every \\(\\mathrm{w}_b^{li}\\) and save it into a dictionary \\(\\mathcal{C}\\) using Eq. (6)." + }, + { + "type": "equation", + "bbox": [ + 0.512, + 0.524, + 0.892, + 0.567 + ], + "angle": 0, + "content": "\\[\n\\mathcal {C} \\left(\\mathrm {w} _ {b} ^ {l i}\\right) = \\underset {x} {\\operatorname {a r g m i n}} \\left(\\sum_ {i = 1} ^ {C _ {i n} \\times M \\times M} \\| x - \\mathrm {w} _ {b} ^ {l i} \\|\\right); x \\in \\mathbb {C} _ {l}. \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.576, + 0.895, + 0.82 + ], + "angle": 0, + "content": "On the other hand, the total distance from every weight sets to its center is added to the loss function and compels the training to minimize both the cross-entropy loss and the distance among weight sets in a group (distance loss). To strike a balance between optimizing the original and distance loss, we adjust a hyper-parameter \\(\\lambda\\) to achieve an optimal ratio for different BNN models. Besides, a \\(\\gamma\\) parameter serves as a hyper-parameter to control the priority of the original and additional loss during the training. This parameter varies following a specific scheduler during the training process. Particularly, the algorithm prioritizes reducing the MST distance and depth during the initial training phase and gradually shifting its focus toward accuracy at the end of the process. The new loss function is shown in Eq. (7), where \\(\\mathcal{L}_0(\\mathrm{input},\\mathrm{w})\\) is the original loss function. Forward processes are summarized in Algorithm 1." + }, + { + "type": "equation", + "bbox": [ + 0.508, + 0.829, + 0.892, + 0.861 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} (\\text {i n p u t}, \\mathrm {w}) = \\mathcal {L} _ {0} (\\text {i n p u t}, \\mathrm {w}) + \\lambda \\gamma \\sum_ {i} \\| \\mathcal {C} \\left(\\mathrm {w} _ {b} ^ {i}\\right) - \\mathrm {w} _ {b} ^ {i} \\| ^ {2}, \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.895, + 0.903 + ], + "angle": 0, + "content": "It is noticeable that we use pre-trained BNN models for the learning process to avoid diverging during distance op" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.958 + ], + "angle": 0, + "content": "6095" + } + ], + [ + { + "type": "code_caption", + "bbox": [ + 0.08, + 0.092, + 0.468, + 0.107 + ], + "angle": 0, + "content": "Algorithm 1 Forward propagation for the training process." + }, + { + "type": "algorithm", + "bbox": [ + 0.079, + 0.109, + 0.47, + 0.327 + ], + "angle": 0, + "content": "Require: Input data, pre-train full-precision weight (w), threshold \\((\\theta)\\) learning rate \\((\\eta)\\) MST scaling factor \\((\\lambda)\\) \n1: Load pre-train weight (w) \n2: for epoch \\(= 1\\rightarrow E\\) do \n3: \\(\\mathcal{L}_{mst} = 0\\) \n4: for \\(l = 1\\) to L do \n5: \\(\\mathrm{w}_b^l = \\mathrm{Sign}(\\mathrm{w}_l)\\) [33] \n6: \\(\\mathrm{a}_b^{l - 1} = \\mathrm{Sign}(\\mathrm{a}_{l - 1})\\) \n7: for i = 1 to Cout do \n8: Update centers for \\(\\mathrm{w}_b^l\\) . \n9: \\(\\mathcal{C}(\\mathrm{w}_b^{li}) = \\underset {x}{\\operatorname{argmin}}(\\sum_{i = 1}^{C_{in}\\times M\\times M}\\| x - \\mathrm{w}_b^{li}\\|);x\\in \\mathbb{C}_l\\) \n10: \\(\\mathcal{L}_{MST} = \\mathcal{L}_{MST} + \\sum \\| \\mathcal{C}(\\mathrm{w}_b^{li}) - \\mathrm{w}_b^{li}\\| ^2\\) \n11: end for \n12: \\(\\mathrm{a_l} = (\\mathrm{w_b^l*}\\mathrm{a_b^{l - 1}})\\odot \\alpha_l\\) \n13: end for \n14: Compute total loss: \\(\\mathcal{L} = \\mathcal{L}_0 + \\lambda *\\gamma *\\mathcal{L}_{MST}\\) \n15: end for" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.354, + 0.47, + 0.385 + ], + "angle": 0, + "content": "timization time. In this paper, results from ReCu [33] are used and considered the baseline for comparison." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.395, + 0.295, + 0.41 + ], + "angle": 0, + "content": "4.3. Streaming Acceleration" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.418, + 0.47, + 0.522 + ], + "angle": 0, + "content": "Inspired by the streaming architecture in [31], this paper proposes an entire BNN high-speed architecture for BNN models applying our compression method. Specifically, the hardware architecture of a binary convolution layer is shown in Figure 6, in which the process is divided into two steps: 1) loading the input feature map to a line buffer and 2) executing XNOR + Popcount operation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.524, + 0.471, + 0.795 + ], + "angle": 0, + "content": "Loading input. Given a binary convolution layer with \\( M = 3 \\), padding size \\( = 1 \\), firstly, \\( C_{in} \\) input feature maps are gradually loaded into \\( C_{in} \\) line buffers with the size \\( 2 \\times W_{in} + 3 \\). When \\( W_{in} + 2 \\) registers in each line buffer are filled, \\( C_{in} \\times 3 \\times 3 \\) input pixels are selected from the line buffers for the convolution (XNOR + Popcount) operation. In standard calculation approach, the number of XNOR operations used for a binary convolution is \\( C_{out} \\times C_{in} \\times M \\times M \\). These operations can be separated into \\( C_{out} \\) sub-operations corresponding to \\( C_{out} \\) output channels; each sub-operation includes \\( C_{in} \\times M \\times M \\) XNOR bit-operations and requires \\( C_{in} \\times M \\times M \\) corresponding input pixels and weight values. In this proposed architecture, the difference is that the number of inputs for a particular sub-operation is lower than \\( C_{in} \\times M \\times M \\) and equal to the distance between the corresponding vertex and parent vertex as in the constructed graph, except the sub-operation for the root vertex requiring full calculation with \\( C_{in} \\times M \\times M \\) XNORs." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.796, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Perform convolution. This step executes the convolution operation with the order of calculation following the MST. As shown in Figure 6, the output of a specific PE (red arrow) is reused for the next PE to reduce computational cost. The PE for the output channel \\( i^{th} \\) needs \\( d_{ij} \\) weight values and executes \\( d_{ij} \\) XNOR operations with the corresponding Popcount operation, where \\( j \\) is the parent" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.091, + 0.891, + 0.282 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.297, + 0.893, + 0.354 + ], + "angle": 0, + "content": "Figure 6. High-speed hardware accelerator for a binary convolution layer, where the XNORs are simplified with NOT or simple straight connection, while computation on each PE corresponding to each output channel is executed gradually with the MST." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.369, + 0.893, + 0.506 + ], + "angle": 0, + "content": "vertex of the vertex \\( i^{th} \\). Besides, to eliminate memory for convolution weight storage, XNOR operations are simplified to NOT gate or straight connection. In terms of timing violations, we pipeline the Popcount operation by adding register lines among the adder tree to reduce computation complexity in a clock cycle. The exact number of register lines depends on the MST depth, frequency and hardware platform. Thus, depending on practical implementations, we adjust this number to meet the timing requirements." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.521, + 0.633, + 0.538 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.548, + 0.892, + 0.64 + ], + "angle": 0, + "content": "In this section, we conduct experiments including software and hardware implementation to show the effectiveness of the proposed method for BNN compression. Training experiments are executed with the popular datasets CIFAR-10 and ImageNet via Pytorch, while hardware implementation is performed on the Xilinx FPGA platforms." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.651, + 0.844, + 0.667 + ], + "angle": 0, + "content": "5.1. Learning and hardware implementation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.675, + 0.893, + 0.9 + ], + "angle": 0, + "content": "Training implementation: Because our proposed method is independent of other BNN accuracy optimization methods, in this paper, we select training results from the ReCU approach in [33] as a case study for further compressing. In doing so, VGG-small, ResNet-18/20 models are used to evaluate on CIFAR-10 dataset, while ResNet-18/34 are used for ImageNet. Regarding training in detail, we keep the configuration as in [33], except for the learning rate of 0.1. In addition, the \\(\\lambda\\) value is adjusted depending on the training models, datasets, and focused objectives. Meanwhile, the \\(\\gamma\\) parameter is scheduled following the learning rate. In this paper, when training with CIFAR-10, we select 1e-6 for ResNet-18, 5e-6 for ResNet-20, and 4e-6 for VGG-small. Meanwhile, for ImageNet, we select 1e-6 for ResNet-18 and 1e3 for ResNet-34." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6096" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.089, + 0.287, + 0.203 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.105, + 0.211, + 0.293, + 0.223 + ], + "angle": 0, + "content": "a) MST distances of each layer (L)." + }, + { + "type": "image", + "bbox": [ + 0.287, + 0.097, + 0.481, + 0.203 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.341, + 0.211, + 0.448, + 0.223 + ], + "angle": 0, + "content": "b) Accuracy curves." + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.229, + 0.468, + 0.271 + ], + "angle": 0, + "content": "Figure 7. MST distance and top-1 % accuracy during the training process, where the Binary VGG-small model and CIFAR-10 dataset is used for the training experiment with 600 epochs." + }, + { + "type": "table", + "bbox": [ + 0.094, + 0.271, + 0.454, + 0.361 + ], + "angle": 0, + "content": "
λMST-depth#Params (Mbit)#Bit-Ops (GOps)Top-1 Acc. mean ± std (%)
1e-797.31.3910.21792.17 ± 0.07
5e-758.30.9980.18492.09 ± 0.06
1e-654.00.8640.16591.99 ± 0.07
5e-644.00.5320.11591.14 ± 0.08
1e-542.30.4220.09890.17 ± 0.14
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.37, + 0.468, + 0.398 + ], + "angle": 0, + "content": "Table 2. MST depth, number of parameters, bit-Ops, and accuracy w.r.t. different values of \\( \\lambda \\) on CIFAR-10 VGG-small model." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.412, + 0.468, + 0.502 + ], + "angle": 0, + "content": "Hardware implementation: The inference hardware architecture is implemented on a Xilinx FPGA platform called xczu3eg-sbva484 part. Before programming to FPGA, the design is run with the corresponding C/C++ model and simulated via Synopsys VCS. Finally, Vivado 2018.3 is used for the design synthesis and implementation." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.513, + 0.241, + 0.528 + ], + "angle": 0, + "content": "5.2. Ablation Studies" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.537, + 0.468, + 0.567 + ], + "angle": 0, + "content": "In this section, experimental results and discussion related to hyper-parameter \\(\\lambda\\), and \\(\\gamma\\) are described." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.568, + 0.468, + 0.884 + ], + "angle": 0, + "content": "Effect of hyper-parameter \\(\\gamma\\): As explained in Sec. 4.1, an additional loss related to MST distance is added for the learning. The effect of the loss depends on the \\(\\gamma\\), while the \\(\\gamma\\) changes following the epoch. To facilitate the evaluation, Figure 7 provides MST distance curves for all binary convolution layers and training-validation accuracy curves in the entire learning process. In the first half-time, the \\(\\gamma\\) is still significant, and the training focuses on MST distance optimization, while the accuracy optimization is temporarily less affected. Consequently, the MST distance of all binary convolutions is significantly down, especially for the deeper layers with more channels, while the training accuracy suddenly decreases and the validation accuracy goes down and strongly fluctuates at this time. In the second half-time, the training focuses on accuracy optimization with the lower \\(\\gamma\\) value. Thus, the training accuracy tends to increase, while the validation accuracy rises, too, with a lower fluctuation. Although the MST distance also escalates again on all layers, these values are lower than at the initial time, especially on deeper layers. This is the reason why we can save computational costs by using this approach." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.886, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Effect of hyper-parameter \\(\\lambda\\): The hyper-parameter \\(\\lambda\\)" + }, + { + "type": "image", + "bbox": [ + 0.549, + 0.088, + 0.852, + 0.289 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.303, + 0.892, + 0.331 + ], + "angle": 0, + "content": "Figure 8. Number of parameters and MST depth on each convolution layer w.r.t. different \\(\\lambda\\) values." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.355, + 0.892, + 0.642 + ], + "angle": 0, + "content": "helps scale down the effect of the total MST distance to the new loss function. Each model has a different number of layers and channels that directly affects the total MST distance. Therefore, depending on the model, we adjust this hyper-parameter to balance the loss for accuracy and MST distance. In this section, the VGG-small model and CIFAR-10 dataset are used to estimate how the \\(\\lambda\\) impacts the number of parameters, bit-operations, MST-depth, and accuracy with the range of \\(\\lambda\\) from 1e-7 to 1e-5. Table 2 and Figure 8 provide the number of parameters, bit-operations, MST-depth, accuracy, and the number parameters for each binary convolution layer w.r.t different \\(\\lambda\\) values. Accordingly, the number of parameters, bit-operations, and accuracy tend to be lower with higher \\(\\lambda\\) values. However, the number of parameters/bit-ops is considerably reduced at \\(3.3\\times\\), while the accuracy degradation is acceptable with \\(2\\%\\) when increasing the \\(\\lambda\\) from 1e-7 to 1e-5. Besides, the MST depth also decreases when the \\(\\lambda\\) value increases. Especially, when increasing \\(\\lambda\\) from 1e-7 to 5e-7, the depth reduces \\(1.67\\times\\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.651, + 0.791, + 0.667 + ], + "angle": 0, + "content": "5.3. Comparison with SOTA methods" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.675, + 0.892, + 0.884 + ], + "angle": 0, + "content": "To demonstrate the effectiveness of the proposed method, we perform a series of training experiments with various NN models on CIFAR-10, and ImageNet, then compare them with state-of-the-art methods. Specifically, for each NN model, we provide two experimental results corresponding to two cases 1) apply both the learning optimization in Sec. 4.2 and the MST reordering to the final training result (Ours 1); 2) directly apply the MST reordering to pretrained BNN models (Ours 2). In this paper, the pre-trained BNN models we use for fine-tuning and exploring the MST are provided by Xu et al. [33]. In terms of acceleration, a neural network model is fully trained on CIFAR-10 and implemented on an FPGA hardware platform to compare with recent hardware architectures." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.886, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Software training comparison: For CIFAR-10, we" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6097" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.081, + 0.089, + 0.467, + 0.369 + ], + "angle": 0, + "content": "
N-workMethod#Params (Mbit)#Bit-Ops (GOps)Top-1 Acc. (%)
VGG smallRAD[8]4.5710.60390.0
IR-Net[24]4.5710.60390.4
RBNN[20]4.5710.60391.3
Adabin[28]4.5710.60392.3
ReCU[33]4.5710.60392.4
SNN[32]3.0470.19491.0
Ours 1|20.556|1.6110.122|0.23291.5|93.3*
ResNet 18RAD[8]10.990.54790.5
IR-Net[24]10.990.54791.5
RBNN[20]10.990.54792.2
ReCU[33]10.990.54792.8
Adabin[28]10.990.54793.1
SNN[33]7.3240.28991.0
Ours 1|20.814|4.2930.104|0.21691.6|93.2*
ResNet 20DSQ[11]0.2670.04084.1
IR-Net[24]0.2670.04086.5
RBNN[20]0.2670.04086.5
ReCU[33]0.2670.04087.4
Adabin[28]0.2670.04088.2
SNN[32]0.1780.04085.1
Ours 1|20.096|0.1160.015|0.01786.5|88.0*
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.081, + 0.372, + 0.451, + 0.384 + ], + "angle": 0, + "content": "* Accuracy after fine-tuning is at https://github.com/z-hXu/ReCU [33]." + }, + { + "type": "table_caption", + "bbox": [ + 0.081, + 0.395, + 0.468, + 0.421 + ], + "angle": 0, + "content": "Table 3. Comparison with the state-of-the-art methods on CIFAR-10. The bit-width is 1 for both activation and weight." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.448, + 0.469, + 0.704 + ], + "angle": 0, + "content": "conduct experiments on three neural BNN models: RestNet-18/20 and VGG-small. we compare our results with RAD [8], IR-Net [24], Adabin [28], ReCU [33], DSQ [11], and SNN [32]. Specifically, as shown in Table 3, when comparing Ours 1 with the highest-accuracy methods on all models, our proposed method reduces \\(8.2 \\times\\) parameters and \\(4.9 \\times\\) bit-Ops with a \\(0.97\\%\\) accuracy drop on VGG-small. Meanwhile, when directly exploring the MST on the pre-trained models, Ours 2 gets \\(2.8 \\times\\) parameters and \\(2.6 \\times\\) bit-Ops reduction without accuracy degradation. On ResNet-18, Ours 1 gives \\(13.50 \\times\\) parameters, \\(5.26 \\times\\) bit-Ops reduction with a \\(1.29\\%\\) accuracy drop, while Ours 2 reduces \\(2.6 \\times\\) parameters and \\(2.5 \\times\\) bit-Ops without compromising accuracy. Additionally, we have \\(2.78 \\times\\) parameters, \\(2.67 \\times\\) bit-Ops reduction, and a \\(1\\%\\) accuracy drop with Ours 1; \\(2.3 \\times\\) parameters, \\(2.35 \\times\\) bit-Ops reduction and \\(0\\%\\) accuracy drop on ResNet-20." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.705, + 0.468, + 0.839 + ], + "angle": 0, + "content": "Compared Ours 1 with the compression method SNN [32] on all models, the proposed method obtains a better compression ratio with a maximum reduction of \\(9.0 \\times\\) parameters, \\(2.78 \\times\\) bit-Ops on ResNet-18 while yielding higher accuracy and up to maximum \\(1.4\\%\\) on ResNet-20. Meanwhile, with Our 2, we reduce maximum \\(1.89 \\times\\) parameters on VGG-small, \\(2.35 \\times\\) bit-Ops on ResNet-20, while achieving higher accuracy up to maximum \\(2.9\\%\\) on ResNet-20." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.841, + 0.468, + 0.9 + ], + "angle": 0, + "content": "For ImageNet, experiments are implemented on ResNet18/34 and comparison is performed with BNN+ [16], BiReal [23], XNOR++ [4], IR-Net [24], Adabin [28], ReCU [33], SNN [32]. According to Table 4, Ours 1 reduces \\(3.2 \\times\\)" + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.089, + 0.888, + 0.284 + ], + "angle": 0, + "content": "
N-workMethod#Params (Mbit)#Bit-Ops (GOps)Top-1 Acc. (%)
ResNet 18BNN+[16]10.991.67753.0
Bi-Real[23]10.991.67756.4
XNOR++[4]10.991.67757.1
IR-Net[24]10.991.67758.1
Adabin[28]10.991.67763.1
ReCU[33]10.991.67761.0
SNN[32]7.320.88356.3
Ours 1|23.43|4.840.636|0.71657.0|61.2*
ResNet 34Bi-Real[23]21.093.52662.2
IR-Net[24]21.093.52662.9
Adabin[28]21.093.52666.4
ReCU[33]21.093.52665.1
SNN[32]14.061.69661.4
Ours 1|29.44|9.511.550|1.55862.9|65.4*
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.506, + 0.287, + 0.875, + 0.3 + ], + "angle": 0, + "content": "* Accuracy after fine-tuning is at https://github.com/z-hXu/ReCU [33]." + }, + { + "type": "table_caption", + "bbox": [ + 0.504, + 0.31, + 0.89, + 0.337 + ], + "angle": 0, + "content": "Table 4. Comparison with the state-of-the-art methods on ImageNet. The bit-width is 1 for both activation and weight." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.363, + 0.89, + 0.574 + ], + "angle": 0, + "content": "parameters, \\(2.6 \\times\\) bit-Ops on ResNet-18; and \\(2.23 \\times\\) parameters, \\(2.27 \\times\\) bit-Ops on ResNet-34, compared to the baseline [33], while the accuracy degradation is \\(4\\%\\) and \\(2.2\\%\\) on ResNet18 and ResNet-34, respectively. Ours 2 achieves \\(2.27 \\times\\) parameters, \\(2.34 \\times\\) bit-Ops reduction on ResNet-18; and \\(2.2 \\times\\) parameters, \\(2.26 \\times\\) bit-Ops reduction without accuracy drop. Compared to SNN with the highest compression ratio recently, our proposed method with Ours 1 saves \\(2.13 \\times\\) parameters and \\(1.3 \\times\\) bit-Ops on ResNet-18, \\(1.49 \\times\\) parameters and \\(1.09 \\times\\) bit-Ops on ResNet-34, while the trained models give higher accuracy of \\(0.7\\%\\) and \\(1.5\\%\\) on ResNet-18, ResNet-34, respectively. Meanwhile, Ours 2 without accuracy drop saves up to \\(1.51 / 1.47 \\times\\) parameters and \\(1.23 / 1.08 \\times\\) bit-Ops on ResNet-18/34, respectively." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.575, + 0.89, + 0.8 + ], + "angle": 0, + "content": "Hardware implementation comparison: Table 5 provides the hardware performance comparison with previous works using CIFAR-10 for the training. We compare the proposed architecture with FINN [30], FINN-R [3] from Xilinx, ReBNet [10] and the design in [31]. Accordingly, the proposed accelerator takes the leading place in both speed and area efficiency (FPS/LUTs). More specifically, it performs \\(1.6 \\times\\) faster than the fastest previous work (FINN), while obtaining \\(3.7 \\times\\) area efficiency with a little higher accuracy. In addition, compared to [31], our method gains over \\(1.81 \\times\\) area efficiency. Besides, to compare our method with the K-mean approach, we implement another design from the same training result with the K-mean method. According to Table 5, our method performs better \\(1.25 \\times\\) in terms of resources and area efficiency." + }, + { + "type": "title", + "bbox": [ + 0.504, + 0.816, + 0.617, + 0.83 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.841, + 0.89, + 0.9 + ], + "angle": 0, + "content": "In conclusion, this paper introduces a comprehensive method for compressing BNNs, which covers the entire process from learning to hardware implementation. By utilizing the minimum spanning tree (MST), we effectively re" + }, + { + "type": "page_number", + "bbox": [ + 0.485, + 0.947, + 0.514, + 0.957 + ], + "angle": 0, + "content": "6098" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.097, + 0.089, + 0.451, + 0.224 + ], + "angle": 0, + "content": "
DesignFreq (MHz)LUTsAcc. (%)FPS (K)FPS/ LUTs
FINN[30]20046,25380.1220.47
FINN[30]125365,96380.11280.35
FINN-R[3]237332,63780.11050.31
FINN-R[3]30041,73380.1200.48
FINN[3]30025,43180.11.90.07
ReBNet[10]20053,20080.660.11
[31]210290,01280.22050.70
Ours (K-mean)210201,43480.52051.01
Ours (MST)210161,29480.52051.27
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.234, + 0.47, + 0.262 + ], + "angle": 0, + "content": "Table 5. Hardware performance comparison with the state-of-the-art architectures on CIFAR-10." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.277, + 0.469, + 0.385 + ], + "angle": 0, + "content": "duce the computation cost of binary convolution calculation. To optimize the MST during the training stage, a learning algorithm is proposed. Moreover, we present a hardware implementation for the inference task. Our experimental results demonstrate that the proposed method significantly reduces computation costs while maintaining high accuracy, making it promising for practical applications." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.399, + 0.266, + 0.417 + ], + "angle": 0, + "content": "7. Acknowledgements" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.424, + 0.47, + 0.56 + ], + "angle": 0, + "content": "This work was supported by the NRF grant funded by the Korea government(MSIT) (No. RS-2023-00207816), and part by IITP Grant funded by MSIT (Artificial Intelligence Innovation Hub) under Grant 2021-0-02068, (No. RS-2022-00155911, AI Convergence Innovation Human Resources Development (Kyung Hee University)), IITP No.2019-0-01287, Evolvable Deep Learning Model Generation Platform for Edge Computing and ITRC support program (IITP-2023-RS-2023-00258649)." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.576, + 0.174, + 0.592 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.603, + 0.469, + 0.643 + ], + "angle": 0, + "content": "[1] Richard Bellman. Dynamic programming treatment of the travelling salesman problem. Journal of the ACM (JACM), 9(1):61-63, 1962. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.646, + 0.469, + 0.7 + ], + "angle": 0, + "content": "[2] Yoshua Bengio, Nicholas Léonard, and Aaron Courville. Estimating or propagating gradients through stochastic neurons for conditional computation. arXiv preprint arXiv:1308.3432, 2013. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.704, + 0.469, + 0.785 + ], + "angle": 0, + "content": "[3] Michaela Blott, Thomas B Preußer, Nicholas J Fraser, Giulio Gambardella, Kenneth O'brien, Yaman Umuroglu, Miriam Leeser, and Kees Vissers. Finn-r: An end-to-end deep-learning framework for fast exploration of quantized neural networks. ACM Transactions on Reconfigurable Technology and Systems (TRETS), 11(3):1-23, 2018. 2, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.789, + 0.469, + 0.829 + ], + "angle": 0, + "content": "[4] Adrian Bulat and Georgios Tzimiropoulos. Xnornet++: Improved binary neural networks. arXiv preprint arXiv:1909.13863, 2019. 1, 3, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.832, + 0.469, + 0.899 + ], + "angle": 0, + "content": "[5] Zhaowei Cai, Xiaodong He, Jian Sun, and Nuno Vasconcelos. Deep learning with low precision by half-wave gaussian quantization. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5918-5926, 2017. 2" + }, + { + "type": "list", + "bbox": [ + 0.087, + 0.603, + 0.469, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.093, + 0.893, + 0.147 + ], + "angle": 0, + "content": "[6] Yu-Hsin Chen, Tushar Krishna, Joel S Emer, and Vivienne Sze. Eyeriss: An energy-efficient reconfigurable accelerator for deep convolutional neural networks. IEEE journal of solid-state circuits, 52(1):127-138, 2016. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.15, + 0.894, + 0.217 + ], + "angle": 0, + "content": "[7] Matthieu Courbariaux, Itay Hubara, Daniel Soudry, Ran El-Yaniv, and Yoshua Bengio. Binarized neural networks: Training deep neural networks with weights and activations constrained to + 1 or -1. arXiv preprint arXiv:1602.02830, 2016. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.22, + 0.893, + 0.289 + ], + "angle": 0, + "content": "[8] Ruizhou Ding, Ting-Wu Chin, Zeye Liu, and Diana Marculescu. Regularizing activation distribution for training binarized deep networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 11408-11417, 2019. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.291, + 0.893, + 0.345 + ], + "angle": 0, + "content": "[9] Cheng Fu, Shilin Zhu, Hao Su, Ching-En Lee, and Jishen Zhao. Towards fast and energy-efficient binarized neural network inference on fpga. arXiv preprint arXiv:1810.02068, 2018. 1, 2, 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.348, + 0.892, + 0.416 + ], + "angle": 0, + "content": "[10] Mohammad Ghasemzadeh, Mohammad Samragh, and Farinaz Koushanfar. Rebnet: Residual binarized neural network. In 2018 IEEE 26th annual international symposium on field-programmable custom computing machines (FCCM), pages 57-64. IEEE, 2018. 2, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.419, + 0.892, + 0.5 + ], + "angle": 0, + "content": "[11] Ruihao Gong, Xianglong Liu, Shenghu Jiang, Tianxiang Li, Peng Hu, Jiazhen Lin, Fengwei Yu, and Junjie Yan. Differentiable soft quantization: Bridging full-precision and low-bit neural networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4852–4861, 2019. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.503, + 0.892, + 0.557 + ], + "angle": 0, + "content": "[12] Song Han, Huizi Mao, and William J Dally. Deep compression: Compressing deep neural networks with pruning, trained quantization and huffman coding. arXiv preprint arXiv:1510.00149, 2015. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.56, + 0.892, + 0.613 + ], + "angle": 0, + "content": "[13] John A Hartigan and Manchek A Wong. Algorithm as 136: A k-means clustering algorithm. Journal of the royal statistical society. series c (applied statistics), 28(1):100-108, 1979. 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.617, + 0.892, + 0.672 + ], + "angle": 0, + "content": "[14] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 1, 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.674, + 0.892, + 0.715 + ], + "angle": 0, + "content": "[15] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, et al. Distilling the knowledge in a neural network. arXiv preprint arXiv:1503.02531, 2(7), 2015. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.717, + 0.892, + 0.77 + ], + "angle": 0, + "content": "[16] Itay Hubara, Matthieu Courbariaux, Daniel Soudry, Ran El-Yaniv, and Yoshua Bengio. Binarized neural networks. Advances in neural information processing systems, 29, 2016. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.774, + 0.892, + 0.841 + ], + "angle": 0, + "content": "[17] Hyeonuk Kim, Jaehyeong Sim, Yeongjae Choi, and Lee-Sup Kim. A kernel decomposition architecture for binary-weight convolutional neural networks. In Proceedings of the 54th Annual Design Automation Conference 2017, pages 1-6, 2017. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.844, + 0.892, + 0.872 + ], + "angle": 0, + "content": "[18] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images. 2009. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.874, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[19] Dongsoo Lee, Se Jung Kwon, Byeongwook Kim, Yongkwon Jeon, Baeseong Park, and Jeongin Yun. Flexor: Train" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6099" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.469, + 0.12 + ], + "angle": 0, + "content": "able fractional quantization. Advances in neural information processing systems, 33:1311-1321, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.121, + 0.469, + 0.176 + ], + "angle": 0, + "content": "[20] Mingbao Lin, Rongrong Ji, Zihan Xu, Baochang Zhang, Yan Wang, Yongjian Wu, Feiyue Huang, and Chia-Wen Lin. Rotated binary neural network. Advances in neural information processing systems, 33:7474-7485, 2020. 1, 3, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.177, + 0.469, + 0.218 + ], + "angle": 0, + "content": "[21] Xiaofan Lin, Cong Zhao, and Wei Pan. Towards accurate binary convolutional neural network. Advances in neural information processing systems, 30, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.218, + 0.469, + 0.287 + ], + "angle": 0, + "content": "[22] Zechun Liu, Zhiqiang Shen, Marios Savvides, and Kwang-Ting Cheng. Reactnet: Towards precise binary neural network with generalized activation functions. In European conference on computer vision, pages 143-159. Springer, 2020. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.288, + 0.469, + 0.37 + ], + "angle": 0, + "content": "[23] Zechun Liu, Baoyuan Wu, Wenhan Luo, Xin Yang, Wei Liu, and Kwang-Ting Cheng. Bi-real net: Enhancing the performance of 1-bit cnns with improved representational capability and advanced training algorithm. In Proceedings of the European conference on computer vision (ECCV), pages 722-737, 2018. 1, 3, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.371, + 0.469, + 0.453 + ], + "angle": 0, + "content": "[24] Haotong Qin, Ruihao Gong, Xianglong Liu, Mingzhu Shen, Ziran Wei, Fengwei Yu, and Jingkuan Song. Forward and backward information retention for accurate binary neural networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2250-2259, 2020. 3, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.455, + 0.469, + 0.51 + ], + "angle": 0, + "content": "[25] Mohammad Rastegari, Vicente Ordonez, Joseph Redmon, and Ali Farhadi. Xnor-net: Imagenet classification using binary convolutional neural networks. In European conference on computer vision, pages 525-542. Springer, 2016. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.511, + 0.469, + 0.58 + ], + "angle": 0, + "content": "[26] Olga Russakovsky, Jia Deng, Hao Su, Jonathan Krause, Sanjeev Satheesh, Sean Ma, Zhiheng Huang, Andrej Karpathy, Aditya Khosla, Michael Bernstein, et al. Imagenet large scale visual recognition challenge. International journal of computer vision, 115(3):211-252, 2015. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.58, + 0.469, + 0.649 + ], + "angle": 0, + "content": "[27] Mark Sandler, Andrew Howard, Menglong Zhu, Andrey Zh-moginov, and Liang-Chieh Chen. Mobilenetv2: Inverted residuals and linear bottlenecks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4510-4520, 2018. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.65, + 0.469, + 0.705 + ], + "angle": 0, + "content": "[28] Zhijun Tu, Xinghao Chen, Pengju Ren, and Yunhe Wang. Adabin: Improving binary neural networks with adaptive binary sets. In European Conference on Computer Vision, pages 379-395. Springer, 2022. 3, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.706, + 0.469, + 0.734 + ], + "angle": 0, + "content": "[29] William Thomas Tutte and William Thomas Tutte. Graph theory, volume 21. Cambridge university press, 2001. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.734, + 0.469, + 0.816 + ], + "angle": 0, + "content": "[30] Yaman Umuroglu, Nicholas J Fraser, Giulio Gambardella, Michaela Blott, Philip Leong, Magnus Jahre, and Kees Vissers. Finn: A framework for fast, scalable binarized neural network inference. In Proceedings of the 2017 ACM/SIGDA international symposium on field-programmable gate arrays, pages 65-74, 2017. 1, 2, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.469, + 0.872 + ], + "angle": 0, + "content": "[31] Quang Hieu Vo, Ngoc Linh Le, Faaiz Asim, Lok-Won Kim, and Choong Seon Hong. A deep learning accelerator based on a streaming architecture for binary neural networks. IEEE Access, 10:21141-21159, 2022. 1, 2, 3, 4, 5, 6, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.469, + 0.902 + ], + "angle": 0, + "content": "[32] Yikai Wang, Yi Yang, Fuchun Sun, and Anbang Yao. Sub-bit neural networks: Learning to compress and accelerate binary" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "neural networks. In International Conference on Computer Vision (ICCV), 2021. 1, 2, 3, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.121, + 0.892, + 0.191 + ], + "angle": 0, + "content": "[33] Zihan Xu, Mingbao Lin, Jianzhuang Liu, Jie Chen, Ling Shao, Yue Gao, Yonghong Tian, and Rongrong Ji. Recu: Reviving the dead weights in binary neural networks. In Proceedings of the IEEE/CVF international conference on computer vision, pages 5198-5208, 2021. 1, 2, 3, 5, 6, 7, 8" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.191 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.956 + ], + "angle": 0, + "content": "6100" + } + ] +] \ No newline at end of file diff --git a/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/9bf308bf-7020-43ef-9313-33d2e81da894_origin.pdf b/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/9bf308bf-7020-43ef-9313-33d2e81da894_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..ed64227358cbc54ef5d95164477b64685109a012 --- /dev/null +++ b/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/9bf308bf-7020-43ef-9313-33d2e81da894_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:ea5d229857631a352bea8a4671570e143f72ee0bb4a9596cf6beb71aac4e7ba6 +size 279362 diff --git a/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/full.md b/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/full.md new file mode 100644 index 0000000000000000000000000000000000000000..56ef548f8e10dff5cdfbcc89b4a6c8cb7e0ebc4e --- /dev/null +++ b/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/full.md @@ -0,0 +1,288 @@ +# MST-compression: Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree + +Quang Hieu Vo, Linh-Tam Tran, Sung-Ho Bae, Lok-Won Kim, Choong Seon Hong* +Department of Computer Science and Engineering, Kyung Hee University + +{2019310178, tamlt, shbae, lwk, cshong}@khu.ac.kr + +# Abstract + +Binary neural networks (BNNs) have been widely adopted to reduce the computational cost and memory storage on edge-computing devices by using one-bit representation for activations and weights. However, as neural networks become wider/deeper to improve accuracy and meet practical requirements, the computational burden remains a significant challenge even on the binary version. To address these issues, this paper proposes a novel method called Minimum Spanning Tree (MST) compression that learns to compress and accelerate BNNs. The proposed architecture leverages an observation from previous works that an output channel in a binary convolution can be computed using another output channel and XNOR operations with weights that differ from the weights of the reused channel. We first construct a fully connected graph with vertices corresponding to output channels, where the distance between two vertices is the number of different values between the weight sets used for these outputs. Then, the MST of the graph with the minimum depth is proposed to reorder output calculations, aiming to reduce computational cost and latency. Moreover, we propose a new learning algorithm to reduce the total MST distance during training. Experimental results on benchmark models demonstrate that our method achieves significant compression ratios with negligible accuracy drops, making it a promising approach for resource-constrained edge-computing devices. + +# 1. Introduction + +Deep Neural Networks (DNNs) have been widely applied in many artificial intelligence applications, especially vision tasks with high accuracy [27, 14]. However, the cost of computation and massive storage burden is significantly challenging to deploy DNNs on embedded systems such as mobile devices and other resource-constrained platforms. Many approaches have been proposed and demonstrated + +![](images/77ff917b2ac1456b9f1df437dd8c7e5f39e49923d42ff58e8ab714152a0b0bb2.jpg) +Figure 1. Illustration of kernel compression for BNNs with the Kmean method (a) and the shortest Hamiltonian path (b), in which adding red connections can further reduce the computational cost for both of them. + +![](images/22117411980b0e4eecf7b0650e325a8db2e9a65a0a3cd171a9daa7aa640e7857.jpg) + +their effectiveness in reducing energy and resources while maintaining the deep models' accuracy, including pruning [12], quantization [7], distillation [15], and efficient hardware implementation [6]. Among these methods, quantization with less bit-width for parameter and activation representation is widely used due to its great benefits and possibility in most practical applications. + +Binarized neural network is a particular form of the quantization method in which weight values and activations are converted to 1-bit values. Accordingly, multiplications and accumulation operations can be replaced by XNOR and Popcount operations [7], respectively. In addition, batch normalization is simplified to a threshold comparison [31], while the pooling can be performed with OR operations [30]. Consequently, the compression ratio on memory storage and computational cost is significantly improved, leading to remarkable performance acceleration. Nevertheless, the accuracy degradation is the trade-off of minimizing the bit-width as BNN. Thus, most previous works focus on reducing this accuracy gap [25, 4, 33, 22, 20, 33, 23]. + +Meanwhile, compressing BNNs has not received much attention, with only a few prominent methods [32, 9, 31, 17], where the kernel compression [9, 31] gives impressive results with roughly $50\%$ resources reduction. In particular, given a binary convolution, inspired by an observation that an output channel can be calculated using another out + +put channel and outputs of XNOR operations using weights that respectively differ from the reused channel's weights [9], authors in [31, 9] proposed to construct a fully connected graph, in which each vertex corresponds to an output channel, and distance between two vertices is the number of different values between two weight sets used for the two output channels. Then, based on the graph, they use the K-mean cluster and shortest Hamiltonian path to reorder the convolution output calculation, aiming to reduce the number of XNOR operations. However, these approaches have yet to fully minimize the computational cost as output channels can use less computation. Indeed, Figure 1 (a) illustrates an example of the K-mean method, where two vertices are considered centers of two groups. Two output channels corresponding to centers are fully calculated1, while other vertices reuse their centers for calculation. However, adding a connection between the two centers would enable one to utilize the rest with less computation cost. Additionally, in the shortest Hamiltonian path shown in Figure 1 (b), there may exist a connection to a specific vertex that is shorter than the connection from the preceding vertex in the path, leading to a lower required number of operations for this vertex. Furthermore, time complexity poses a challenge in these methods [1, 13], resulting in longer exploration times. + +To more effectively minimize the number of XNOR operations with the mentioned observation, in all connections to a specific vertex, the minimum connection must be selected to minimize the computation cost for this vertex. In addition, all of these selected connections must be included in a subgraph that visits all vertices exactly once to ensure that only one output channel is fully calculated. As a result, a MST is the only structure that can fulfill these requirements. Therefore, this paper leverages the MST to reorder binary convolution output calculations. Figure 2 shows a simple example of reordering calculation on a convolution. In this example, only the output channel 4 is fully calculated with $C_{in} \times M \times M$ bit-weight values. In contrast, other channels are calculated using output channel 4, following the MST direction. + +On the other hand, to maximize the advantages of the MST, we further minimize the MST distance of all convolution layers with a new learning algorithm right during the training stage. Besides, we propose a hardware accelerator for BNNs applying the MST compression to demonstrate the feasibility and effectiveness of the method related to hardware resources. To the best of our knowledge, this method gives the highest compression ratio with implementation from learning for compression to acceleration. In summary, the following are contributions of this paper: + +- We introduce and analyze the effectiveness of the MST + +![](images/ffb0d321e668f307b83d20e2ce2aaf7a50bcf960cbe5a2f54c32cc9606afaee8.jpg) +Figure 2. The process of arranging the order of computation on a binary convolution layer, in which output channel 4 is fully calculated first. Then, the output channel 4 is used to calculate channel 1, channel 2 and channel 3. + +in reducing the computational cost for the inference on a binary convolution layer. + +- We propose a training algorithm that can reduce the MST distance and depth right during the training process, which consequently maximizes the compression ratio for inference implementation. +- We provide the corresponding hardware acceleration for the proposed method with high throughput and better resource efficiency, compared to related works [3, 30, 31, 10]. + +The experiments are performed for BNNs including VGG-small [5], ResNet-18/20 [14] on CIFAR-10 dataset [18], and ResNet-18/34 [14] on ImageNet [26]. The results show that the proposed approach gives a higher compression ratio than the previous works [32]. Compared to the baseline [33], our method reduces up to $13.5 \times$ the convolution parameters and $5.51 \times$ bit-wise operations on the same model with an acceptable accuracy degradation. Regarding hardware acceleration, we conduct the experiments for a BNN with the same structure as the baseline [31] and apply the proposed approach. Compared to the baseline [31], hardware deployments demonstrate that BNNs with our method save $1.8 \times$ LUTs, and $1.81 \times$ area efficiency while maintaining the acceleration speed and accuracy. + +# 2. Related Work + +Training neural networks with binary weights and activations were first introduced by Coubariaux et al. [7] and then rapidly gained attention from the community due to the high compression ratio. However, accuracy drop is a critical problem of this direction, while compression is still highly demanded. Various techniques are proposed to further compress and improve accuracy based on the binary property. + +For accuracy improvement, Rastegari et al. [25] proposed adding a scaling factor to the convolution to reduce the quantization error. To generalize this idea aiming to enhance accuracy, the authors in [4] extended this factor dimension and enabled its training option as a learnable parameter. Besides, instead of using the Straight Through Estimation (STE) method [2], Liu et al. [23], and Lin et al. [20] proposed using a piece-wise linear and training-aware approximation function, respectively, to approximate the sign function gradient better. Meanwhile, some previous works introduced both new optimization techniques and corresponding BNN to shrink the accuracy gap entirely [22, 21, 28, 24]. For example, based on Bi-real Net in [23], authors in [22] proposed new sign and activation functions to shift and reshape activation distribution with a new baseline neural network model that can boost the performance. Other works look at the binary characteristics from deeper perspectives to limit information loss [20, 28, 33]. For example, KL divergence is employed in [28] to minimize the difference between the distribution of binary and real-weight counterparts. Xu et al. [33] observed the low probability of changing large full-precision weight when binarizing and proposed the ReCu function to revive the death weights, leading to lower quantization error. + +Binary model compression has received less attention as only a few techniques have been proposed so far. Specifically, Lee et al. [19] proposed an encryption algorithm to compress binary weights with lower than 1-bit per weight, and XOR-gate networks are used to decrypt the inference task. Similarly, Sub-bit Neural Networks (SNN) [32] proposed using lower than 9 bits for each $3 \times 3$ binary kernel based on the scattered 9-bit kernel distribution. Other proposed compression methods provided only hardware techniques for inference implementation. Authors in [31, 9] proposed BNN hardware architectures using weight/input reuse with different calculation orders for convolution to reduce hardware overhead. Kim et al. [17] introduces kernel decomposition that can reduce the computational cost by sharing one base output for all channels. + +# 3. Background + +This section briefly describes how to construct a binary convolution layer and the related optimization methods. For a convolution layer with $C_{in}$ input channels, $C_{out}$ output channels, and kernel size $M$ , weights and activations are denoted by $\mathcal{W}^r \in \mathbb{R}^n$ and $A^r \in \mathbb{R}^m$ , where $n = C_{out} \times C_{in} \times M \times M$ and $m = C_{in} \times W_{in} \times H_{in}$ . $W_{in} \times H_{in}$ represents input feature map size. To simplify the computation and reduce memory storage, in a binary convolution layer, the binarization of activations $\mathcal{A}^b \in \{\pm 1\}^m$ and weights $\mathcal{W}^b \in \{\pm 1\}^n$ is acquired by the fol + +![](images/0934753088b843d1756c7c6c4408910c4840ba22359ed9e9593ef8fbde5a8cd0.jpg) +Figure 3. Weight-reuse method description. Here, the red line is counting the number of elements, the green line is summing all elements. $P_{12}$ is $\sum_{j=1}^{d_{12}} \mathrm{XNOR}(\mathcal{A}_{2j}, \mathcal{W}_{2j})$ , and $Y_{2}$ is $2(P_{1} - d_{12} + 2P_{12}) - C_{in} \times M \times M$ . + +lowing sign function [25], + +$$ +x ^ {b} = \operatorname {S i g n} (x) = \left\{ \begin{array}{l} + 1, \text {i f} x \geq 0, \\ - 1, \text {o t h e r w i s e .} \end{array} \right. \tag {1} +$$ + +If $-1$ is substituted by 0 to represent a negative value for $\mathcal{A}^b$ and $\mathcal{W}^b$ , the output convolution operation of the $i^{th}$ channel now is reformulated as in Eq. (2) [31]. + +$$ +Y _ {i} = (2 \sum_ {j = 1} ^ {C _ {i n} M M} \operatorname {X N O R} \left(\mathcal {A} _ {i j} ^ {b}, \mathcal {W} _ {i j} ^ {b}\right) - C _ {i n} \times M \times M) \odot \alpha , \tag {2} +$$ + +where $\sum_{1}^{C_{in}\times M\times M}\mathrm{XNOR}(\mathcal{A}_{ij}^{b},\mathcal{W}_{ij}^{b})$ is the number of set-bits (Popcount) of the output channel $i^{th}$ , $\odot$ is the element-wise multiplication, and $C_{in}\times M\times M$ is the number of bit-wise XNOR operations used to calculate one output channel. The scaling factor $\alpha$ is added as a learnable parameter to lessen quantization error [25]. For backward propagation, following [23], the STE [2] method is used for the approximation gradient on weights, while the piecewise polynomial function [23] is used for gradient approximation on activations. + +To further compress the BNN models, in this paper, we apply the weight reuse method [31] for the inference task. Accordingly, given the $l^{th}$ binary convolution, as shown in Figure 3, we denote $P_{i}$ and $P_{j}$ as the output of the Popcount operations of the output channels $i^{th}$ and $j^{th}$ , respectively. All binary weights of the layer are divided into $C_{out}$ weight sets $w_{b}^{li} \in \{\pm 1\}^{C_{in} \times M \times M}$ , where $i = 1,2,\dots,C_{out}$ and each weight set is used to calculate for an output channel. $d_{ij}$ is the number of weight bits in the $w_{b}^{li}$ that differ from the $w_{b}^{lj}$ , compared one-to-one respectively. $P_{ij}$ is the sum of XNOR operations with the + +![](images/b54dd59fcb9bd5ed24a2c6fd3f40c58b51efc81a0a552c82bdb14eb601b0346e.jpg) +Figure 4. Comparison between the computation process of a standard binary convolution and our method in BNN acceleration. Instead of fully computing all $C_{in} \times M \times M$ XNOR operations for each layer, our method provides an optimal order of the calculation using the MST to minimize the number of XNOR operations and total parameters. + +weights of the channel $j^{th}$ that differ from the $i^{th}$ counterpart. To calculate the output channel $j^{th}$ from the output channel $i^{th}$ , we use Eq. (3). + +$$ +Y _ {j} = 2 \left(P _ {i} - d _ {i j} + 2 P _ {i j}\right) - C _ {i n} \times M \times M. \tag {3} +$$ + +# 4. Methodology + +# 4.1. Minimum Spanning Tree for BNN Acceleration + +For a binary convolution layer, we construct a fully connected graph in which each vertex corresponds to an output channel. The distance between two vertices $i$ and $j$ is $d_{ij}$ . As shown in Eq. (3), an output channel $j$ can be calculated via the Popcount of an output channel $i$ and the Popcount of $d_{ij}$ XNOR operations. That means the number of XNOR operations executed for the output channel $j$ is the distance $d_{ij}$ . Based on this observation, to minimize the number of XNOR operations used for all out + +put channels, we need a sub-graph that includes all vertices with the minimum total edge distances, which is named an MST [29]. Returning to the example in Figure 2, Figure 4 illustrates the computation process of this convolution example with the standard and proposed approach. Specifically, in the standard direction, each output channel needs 9 XNOR operations, while in our direction, only the $4^{th}$ output channel is fully computed by 9 XNOR operations, and the $1^{st}, 2^{nd}, 3^{rd}$ output channels reuse the output channel $4^{th}$ with 2, 3, 2 XNOR operations, respectively. Accordingly, the compression ratio for this example is $(2 + 3 + 2 + 3 \times 3) / (4 \times 1 \times 3 \times 3) = 0.44$ . In general, we can reduce the computational cost for a convolution layer with the following ratio: + +$$ +\mathcal {R} = \frac {\sum_ {j \neq r o o t} ^ {C _ {o u t}} d _ {i j} + C _ {i n} \times M \times M}{C _ {o u t} \times C _ {i n} \times M \times M}, \tag {4} +$$ + +where $i$ is the parent of the vertex $j$ . If $j$ is the root of the MST, this output uses $C_{in} \times M \times M$ binary weight values. + +Regarding parameters, because the streaming architecture described in Sec. 4.3 is fully implemented with all layers on the FPGA platform, weights' locations can be converted to connections from inputs to the correct XNORs and corresponding weight values at the circuit level. Thus, our proposed method counts only the parameters we need for XNOR logic gates, as shown in Figure 4. + +Number of bit-wise operations. Compared with the previous approaches [31, 9], in a binary convolution layer, the proposed method can better reduce the number of XNORs and parameters. Firstly, as explained in the previous section, adding connections among centers leads to less computation for the K-mean approach [31] as in Eq. (5). + +$$ +\sum_ {j} d _ {i j} + C _ {i n} \times M \times M < \sum_ {j \notin C} d _ {i j} + R \times C _ {i n} \times M \times M, \tag {5} +$$ + +where $C$ includes all centers, $R$ is the number of centers. Furthermore, adding connections among centers also creates a spanning tree, whose computational cost is always equal to or higher than using an MST. Secondly, in [9], the authors proposed using the shortest Hamiltonian path to arrange the computation order. Because this path visits all vertices exactly once, the shortest Hamiltonian path is also a spanning tree. Therefore, the number of XNOR bit-wise operations using an MST method is equal to or lower than the shortest Hamiltonian path. + +Exploration time. The MST is faster and less complex for finding the computation order, compared to previous work [9, 31]. Indeed, the MST is found by Prim's algorithm with the complexity of $O(V^2)$ [29], where $V$ is the number of vertices. In contrast, the K-mean algorithm requires $O(V^2 G)$ [13] time complexity, where $G$ denotes the number of groups. Since the optimal number of groups varies + +![](images/921cf3b22ea120edb42a983200a658268c1be835f1007d23d06cee503cfd5235.jpg) +Figure 5. a) The computation tree's depth using the K-mean cluster. b) The computation tree's depth using the shortest Hamiltonian path. c) The computation tree's depth using the MST. + +
LHamiltonianK-meanMST
Bit-OpsTimeBit-OpsTimeBit-OpsTime
11.08 M31.3 s1.33 M0.090 s1.07 M0.021 s
21.09 M32.9 s1.30 M0.075 s1.06 M0.021 s
31.07 M32.6 s1.30 M0.085 s1.05 M0.023 s
41.10 M32.7 s1.33 M0.076 s1.08 M0.021 s
51.11 M32.5 s1.32 M0.115 s1.09 M0.020 s
61.09 M32.5 s1.33 M0.086 s1.08 M0.021 s
+ +Table 1. Bit-Ops and running time w.r.t. different approaches for reordering calculation on the first 6 convolution layers of ResNet20 with 16 output channels. + +across convolutions, extra time is needed to determine this number for each case. Meanwhile, the shortest Hamiltonian path has a much higher time complexity of $O(V^{2}2^{V})$ [1], making it challenging to apply in practical settings. To estimate these approaches for practical operation, we perform experiments for the first 6 binary convolution layers of ResNet-20 [14] with the weight data trained by [33], while experiments on deeper layers with a larger number of output channels are infeasible even uncompleted for the K-mean and the shortest Hamiltonian path approach due to their longer running times. According to Table 1, the MST approach gives the lowest bit-Ops and exploration time. + +Computation latency. This is one of the factors affecting the resource overhead. This paper focuses on improving the architecture in [31], a streaming acceleration for BNNs. In doing so, the deeper the computation tree, the longer latency between the time output of the first and the last channel comes out. Consequently, the number of added registers (Flip-flops) for synchronization tends to be equal or more for the deeper tree because all output channels must be available at the same clock for the next convolution operation. The exact number of added registers depends on the number of adders executed in a clock period, which is affected by the required frequency, design complexity, and hardware platform. Thus, to evaluate the comprehensive effects of the depth with practical implementations, the experiments related to this comparison are provided in Sec. 5. + +Figure 5 visually describes the depth of the MST, K-mean cluster, and the shortest Hamiltonian path approach. Accordingly, the depths of the K-mean method and the shortest Hamiltonian path are always 1 and $V$ , respectively. Meanwhile, the MST's depth can range from 1 to $V$ , depending on the graph structure. Therefore, the proposed method is always better than the shortest Hamiltonian path in all aspects (number of operations, latency, running time). Meanwhile, the K-mean method gives a better latency but much worse for the rest. After exploring an MST for the posttraining stage to limit the impact of the tree depth on latency and resources, we continue finding a new root that makes the depth of the new tree minimum. + +# 4.2. Learning Optimization + +According to the observation mentioned earlier, to enhance the benefits of the MST approach, we propose a simple learning method that can further reduce the MST depth and total MST distance over a BNN model. Specifically, to make the training converged, instead of directly optimizing the MST, we cluster weight sets $(\mathrm{w}_b^{li})$ to different groups and try to reduce the distance among weight sets in each group by optimizing the distances from all weight sets to fixed centers. In doing so, given the $l^{th}$ binary convolution layer of a BNN model, we first randomly sample a binary center subset $\mathbb{C}_l \subset \{\pm 1\}^{C_{in} \times M \times M}$ and $|\mathbb{C}_l| = N_l$ . Then, we explore the nearest center in $\mathbb{C}_l$ for every $\mathrm{w}_b^{li}$ and save it into a dictionary $\mathcal{C}$ using Eq. (6). + +$$ +\mathcal {C} \left(\mathrm {w} _ {b} ^ {l i}\right) = \underset {x} {\operatorname {a r g m i n}} \left(\sum_ {i = 1} ^ {C _ {i n} \times M \times M} \| x - \mathrm {w} _ {b} ^ {l i} \|\right); x \in \mathbb {C} _ {l}. \tag {6} +$$ + +On the other hand, the total distance from every weight sets to its center is added to the loss function and compels the training to minimize both the cross-entropy loss and the distance among weight sets in a group (distance loss). To strike a balance between optimizing the original and distance loss, we adjust a hyper-parameter $\lambda$ to achieve an optimal ratio for different BNN models. Besides, a $\gamma$ parameter serves as a hyper-parameter to control the priority of the original and additional loss during the training. This parameter varies following a specific scheduler during the training process. Particularly, the algorithm prioritizes reducing the MST distance and depth during the initial training phase and gradually shifting its focus toward accuracy at the end of the process. The new loss function is shown in Eq. (7), where $\mathcal{L}_0(\mathrm{input},\mathrm{w})$ is the original loss function. Forward processes are summarized in Algorithm 1. + +$$ +\mathcal {L} (\text {i n p u t}, \mathrm {w}) = \mathcal {L} _ {0} (\text {i n p u t}, \mathrm {w}) + \lambda \gamma \sum_ {i} \| \mathcal {C} \left(\mathrm {w} _ {b} ^ {i}\right) - \mathrm {w} _ {b} ^ {i} \| ^ {2}, \tag {7} +$$ + +It is noticeable that we use pre-trained BNN models for the learning process to avoid diverging during distance op + +Algorithm 1 Forward propagation for the training process. +Require: Input data, pre-train full-precision weight (w), threshold $(\theta)$ learning rate $(\eta)$ MST scaling factor $(\lambda)$ +1: Load pre-train weight (w) +2: for epoch $= 1\rightarrow E$ do +3: $\mathcal{L}_{mst} = 0$ +4: for $l = 1$ to L do +5: $\mathrm{w}_b^l = \mathrm{Sign}(\mathrm{w}_l)$ [33] +6: $\mathrm{a}_b^{l - 1} = \mathrm{Sign}(\mathrm{a}_{l - 1})$ +7: for i = 1 to Cout do +8: Update centers for $\mathrm{w}_b^l$ . +9: $\mathcal{C}(\mathrm{w}_b^{li}) = \underset {x}{\operatorname{argmin}}(\sum_{i = 1}^{C_{in}\times M\times M}\| x - \mathrm{w}_b^{li}\|);x\in \mathbb{C}_l$ +10: $\mathcal{L}_{MST} = \mathcal{L}_{MST} + \sum \| \mathcal{C}(\mathrm{w}_b^{li}) - \mathrm{w}_b^{li}\| ^2$ +11: end for +12: $\mathrm{a_l} = (\mathrm{w_b^l*}\mathrm{a_b^{l - 1}})\odot \alpha_l$ +13: end for +14: Compute total loss: $\mathcal{L} = \mathcal{L}_0 + \lambda *\gamma *\mathcal{L}_{MST}$ +15: end for + +timization time. In this paper, results from ReCu [33] are used and considered the baseline for comparison. + +# 4.3. Streaming Acceleration + +Inspired by the streaming architecture in [31], this paper proposes an entire BNN high-speed architecture for BNN models applying our compression method. Specifically, the hardware architecture of a binary convolution layer is shown in Figure 6, in which the process is divided into two steps: 1) loading the input feature map to a line buffer and 2) executing XNOR + Popcount operation. + +Loading input. Given a binary convolution layer with $M = 3$ , padding size $= 1$ , firstly, $C_{in}$ input feature maps are gradually loaded into $C_{in}$ line buffers with the size $2 \times W_{in} + 3$ . When $W_{in} + 2$ registers in each line buffer are filled, $C_{in} \times 3 \times 3$ input pixels are selected from the line buffers for the convolution (XNOR + Popcount) operation. In standard calculation approach, the number of XNOR operations used for a binary convolution is $C_{out} \times C_{in} \times M \times M$ . These operations can be separated into $C_{out}$ sub-operations corresponding to $C_{out}$ output channels; each sub-operation includes $C_{in} \times M \times M$ XNOR bit-operations and requires $C_{in} \times M \times M$ corresponding input pixels and weight values. In this proposed architecture, the difference is that the number of inputs for a particular sub-operation is lower than $C_{in} \times M \times M$ and equal to the distance between the corresponding vertex and parent vertex as in the constructed graph, except the sub-operation for the root vertex requiring full calculation with $C_{in} \times M \times M$ XNORs. + +Perform convolution. This step executes the convolution operation with the order of calculation following the MST. As shown in Figure 6, the output of a specific PE (red arrow) is reused for the next PE to reduce computational cost. The PE for the output channel $i^{th}$ needs $d_{ij}$ weight values and executes $d_{ij}$ XNOR operations with the corresponding Popcount operation, where $j$ is the parent + +![](images/24fc45c146751253c6dc920dec9d9f014fee081123fc86c2039f5eeb0e738390.jpg) +Figure 6. High-speed hardware accelerator for a binary convolution layer, where the XNORs are simplified with NOT or simple straight connection, while computation on each PE corresponding to each output channel is executed gradually with the MST. + +vertex of the vertex $i^{th}$ . Besides, to eliminate memory for convolution weight storage, XNOR operations are simplified to NOT gate or straight connection. In terms of timing violations, we pipeline the Popcount operation by adding register lines among the adder tree to reduce computation complexity in a clock cycle. The exact number of register lines depends on the MST depth, frequency and hardware platform. Thus, depending on practical implementations, we adjust this number to meet the timing requirements. + +# 5. Experiments + +In this section, we conduct experiments including software and hardware implementation to show the effectiveness of the proposed method for BNN compression. Training experiments are executed with the popular datasets CIFAR-10 and ImageNet via Pytorch, while hardware implementation is performed on the Xilinx FPGA platforms. + +# 5.1. Learning and hardware implementation + +Training implementation: Because our proposed method is independent of other BNN accuracy optimization methods, in this paper, we select training results from the ReCU approach in [33] as a case study for further compressing. In doing so, VGG-small, ResNet-18/20 models are used to evaluate on CIFAR-10 dataset, while ResNet-18/34 are used for ImageNet. Regarding training in detail, we keep the configuration as in [33], except for the learning rate of 0.1. In addition, the $\lambda$ value is adjusted depending on the training models, datasets, and focused objectives. Meanwhile, the $\gamma$ parameter is scheduled following the learning rate. In this paper, when training with CIFAR-10, we select 1e-6 for ResNet-18, 5e-6 for ResNet-20, and 4e-6 for VGG-small. Meanwhile, for ImageNet, we select 1e-6 for ResNet-18 and 1e3 for ResNet-34. + +![](images/ff6d24f46fdba1ec89158f7e31442b3bb87c5439ac9bb2efbffbb5383ce29bde.jpg) +a) MST distances of each layer (L). + +![](images/d96762b1efc4b4120336a51095a3cb0e1f929b9dd07665213e29cf4cbf3c9772.jpg) +b) Accuracy curves. +Figure 7. MST distance and top-1 % accuracy during the training process, where the Binary VGG-small model and CIFAR-10 dataset is used for the training experiment with 600 epochs. + +
λMST-depth#Params (Mbit)#Bit-Ops (GOps)Top-1 Acc. mean ± std (%)
1e-797.31.3910.21792.17 ± 0.07
5e-758.30.9980.18492.09 ± 0.06
1e-654.00.8640.16591.99 ± 0.07
5e-644.00.5320.11591.14 ± 0.08
1e-542.30.4220.09890.17 ± 0.14
+ +Table 2. MST depth, number of parameters, bit-Ops, and accuracy w.r.t. different values of $\lambda$ on CIFAR-10 VGG-small model. + +Hardware implementation: The inference hardware architecture is implemented on a Xilinx FPGA platform called xczu3eg-sbva484 part. Before programming to FPGA, the design is run with the corresponding C/C++ model and simulated via Synopsys VCS. Finally, Vivado 2018.3 is used for the design synthesis and implementation. + +# 5.2. Ablation Studies + +In this section, experimental results and discussion related to hyper-parameter $\lambda$ , and $\gamma$ are described. + +Effect of hyper-parameter $\gamma$ : As explained in Sec. 4.1, an additional loss related to MST distance is added for the learning. The effect of the loss depends on the $\gamma$ , while the $\gamma$ changes following the epoch. To facilitate the evaluation, Figure 7 provides MST distance curves for all binary convolution layers and training-validation accuracy curves in the entire learning process. In the first half-time, the $\gamma$ is still significant, and the training focuses on MST distance optimization, while the accuracy optimization is temporarily less affected. Consequently, the MST distance of all binary convolutions is significantly down, especially for the deeper layers with more channels, while the training accuracy suddenly decreases and the validation accuracy goes down and strongly fluctuates at this time. In the second half-time, the training focuses on accuracy optimization with the lower $\gamma$ value. Thus, the training accuracy tends to increase, while the validation accuracy rises, too, with a lower fluctuation. Although the MST distance also escalates again on all layers, these values are lower than at the initial time, especially on deeper layers. This is the reason why we can save computational costs by using this approach. + +Effect of hyper-parameter $\lambda$ : The hyper-parameter $\lambda$ + +![](images/c8a4a7b419849b5c80518ae23408d7bd904294f01ab40ac5c33c96e40815e45f.jpg) +Figure 8. Number of parameters and MST depth on each convolution layer w.r.t. different $\lambda$ values. + +helps scale down the effect of the total MST distance to the new loss function. Each model has a different number of layers and channels that directly affects the total MST distance. Therefore, depending on the model, we adjust this hyper-parameter to balance the loss for accuracy and MST distance. In this section, the VGG-small model and CIFAR-10 dataset are used to estimate how the $\lambda$ impacts the number of parameters, bit-operations, MST-depth, and accuracy with the range of $\lambda$ from 1e-7 to 1e-5. Table 2 and Figure 8 provide the number of parameters, bit-operations, MST-depth, accuracy, and the number parameters for each binary convolution layer w.r.t different $\lambda$ values. Accordingly, the number of parameters, bit-operations, and accuracy tend to be lower with higher $\lambda$ values. However, the number of parameters/bit-ops is considerably reduced at $3.3\times$ , while the accuracy degradation is acceptable with $2\%$ when increasing the $\lambda$ from 1e-7 to 1e-5. Besides, the MST depth also decreases when the $\lambda$ value increases. Especially, when increasing $\lambda$ from 1e-7 to 5e-7, the depth reduces $1.67\times$ . + +# 5.3. Comparison with SOTA methods + +To demonstrate the effectiveness of the proposed method, we perform a series of training experiments with various NN models on CIFAR-10, and ImageNet, then compare them with state-of-the-art methods. Specifically, for each NN model, we provide two experimental results corresponding to two cases 1) apply both the learning optimization in Sec. 4.2 and the MST reordering to the final training result (Ours 1); 2) directly apply the MST reordering to pretrained BNN models (Ours 2). In this paper, the pre-trained BNN models we use for fine-tuning and exploring the MST are provided by Xu et al. [33]. In terms of acceleration, a neural network model is fully trained on CIFAR-10 and implemented on an FPGA hardware platform to compare with recent hardware architectures. + +Software training comparison: For CIFAR-10, we + +
N-workMethod#Params (Mbit)#Bit-Ops (GOps)Top-1 Acc. (%)
VGG smallRAD[8]4.5710.60390.0
IR-Net[24]4.5710.60390.4
RBNN[20]4.5710.60391.3
Adabin[28]4.5710.60392.3
ReCU[33]4.5710.60392.4
SNN[32]3.0470.19491.0
Ours 1|20.556|1.6110.122|0.23291.5|93.3*
ResNet 18RAD[8]10.990.54790.5
IR-Net[24]10.990.54791.5
RBNN[20]10.990.54792.2
ReCU[33]10.990.54792.8
Adabin[28]10.990.54793.1
SNN[33]7.3240.28991.0
Ours 1|20.814|4.2930.104|0.21691.6|93.2*
ResNet 20DSQ[11]0.2670.04084.1
IR-Net[24]0.2670.04086.5
RBNN[20]0.2670.04086.5
ReCU[33]0.2670.04087.4
Adabin[28]0.2670.04088.2
SNN[32]0.1780.04085.1
Ours 1|20.096|0.1160.015|0.01786.5|88.0*
+ +* Accuracy after fine-tuning is at https://github.com/z-hXu/ReCU [33]. + +conduct experiments on three neural BNN models: RestNet-18/20 and VGG-small. we compare our results with RAD [8], IR-Net [24], Adabin [28], ReCU [33], DSQ [11], and SNN [32]. Specifically, as shown in Table 3, when comparing Ours 1 with the highest-accuracy methods on all models, our proposed method reduces $8.2 \times$ parameters and $4.9 \times$ bit-Ops with a $0.97\%$ accuracy drop on VGG-small. Meanwhile, when directly exploring the MST on the pre-trained models, Ours 2 gets $2.8 \times$ parameters and $2.6 \times$ bit-Ops reduction without accuracy degradation. On ResNet-18, Ours 1 gives $13.50 \times$ parameters, $5.26 \times$ bit-Ops reduction with a $1.29\%$ accuracy drop, while Ours 2 reduces $2.6 \times$ parameters and $2.5 \times$ bit-Ops without compromising accuracy. Additionally, we have $2.78 \times$ parameters, $2.67 \times$ bit-Ops reduction, and a $1\%$ accuracy drop with Ours 1; $2.3 \times$ parameters, $2.35 \times$ bit-Ops reduction and $0\%$ accuracy drop on ResNet-20. + +Compared Ours 1 with the compression method SNN [32] on all models, the proposed method obtains a better compression ratio with a maximum reduction of $9.0 \times$ parameters, $2.78 \times$ bit-Ops on ResNet-18 while yielding higher accuracy and up to maximum $1.4\%$ on ResNet-20. Meanwhile, with Our 2, we reduce maximum $1.89 \times$ parameters on VGG-small, $2.35 \times$ bit-Ops on ResNet-20, while achieving higher accuracy up to maximum $2.9\%$ on ResNet-20. + +For ImageNet, experiments are implemented on ResNet18/34 and comparison is performed with BNN+ [16], BiReal [23], XNOR++ [4], IR-Net [24], Adabin [28], ReCU [33], SNN [32]. According to Table 4, Ours 1 reduces $3.2 \times$ + +Table 3. Comparison with the state-of-the-art methods on CIFAR-10. The bit-width is 1 for both activation and weight. + +
N-workMethod#Params (Mbit)#Bit-Ops (GOps)Top-1 Acc. (%)
ResNet 18BNN+[16]10.991.67753.0
Bi-Real[23]10.991.67756.4
XNOR++[4]10.991.67757.1
IR-Net[24]10.991.67758.1
Adabin[28]10.991.67763.1
ReCU[33]10.991.67761.0
SNN[32]7.320.88356.3
Ours 1|23.43|4.840.636|0.71657.0|61.2*
ResNet 34Bi-Real[23]21.093.52662.2
IR-Net[24]21.093.52662.9
Adabin[28]21.093.52666.4
ReCU[33]21.093.52665.1
SNN[32]14.061.69661.4
Ours 1|29.44|9.511.550|1.55862.9|65.4*
+ +* Accuracy after fine-tuning is at https://github.com/z-hXu/ReCU [33]. + +Table 4. Comparison with the state-of-the-art methods on ImageNet. The bit-width is 1 for both activation and weight. + +parameters, $2.6 \times$ bit-Ops on ResNet-18; and $2.23 \times$ parameters, $2.27 \times$ bit-Ops on ResNet-34, compared to the baseline [33], while the accuracy degradation is $4\%$ and $2.2\%$ on ResNet18 and ResNet-34, respectively. Ours 2 achieves $2.27 \times$ parameters, $2.34 \times$ bit-Ops reduction on ResNet-18; and $2.2 \times$ parameters, $2.26 \times$ bit-Ops reduction without accuracy drop. Compared to SNN with the highest compression ratio recently, our proposed method with Ours 1 saves $2.13 \times$ parameters and $1.3 \times$ bit-Ops on ResNet-18, $1.49 \times$ parameters and $1.09 \times$ bit-Ops on ResNet-34, while the trained models give higher accuracy of $0.7\%$ and $1.5\%$ on ResNet-18, ResNet-34, respectively. Meanwhile, Ours 2 without accuracy drop saves up to $1.51 / 1.47 \times$ parameters and $1.23 / 1.08 \times$ bit-Ops on ResNet-18/34, respectively. + +Hardware implementation comparison: Table 5 provides the hardware performance comparison with previous works using CIFAR-10 for the training. We compare the proposed architecture with FINN [30], FINN-R [3] from Xilinx, ReBNet [10] and the design in [31]. Accordingly, the proposed accelerator takes the leading place in both speed and area efficiency (FPS/LUTs). More specifically, it performs $1.6 \times$ faster than the fastest previous work (FINN), while obtaining $3.7 \times$ area efficiency with a little higher accuracy. In addition, compared to [31], our method gains over $1.81 \times$ area efficiency. Besides, to compare our method with the K-mean approach, we implement another design from the same training result with the K-mean method. According to Table 5, our method performs better $1.25 \times$ in terms of resources and area efficiency. + +# 6. Conclusion + +In conclusion, this paper introduces a comprehensive method for compressing BNNs, which covers the entire process from learning to hardware implementation. By utilizing the minimum spanning tree (MST), we effectively re + +
DesignFreq (MHz)LUTsAcc. (%)FPS (K)FPS/ LUTs
FINN[30]20046,25380.1220.47
FINN[30]125365,96380.11280.35
FINN-R[3]237332,63780.11050.31
FINN-R[3]30041,73380.1200.48
FINN[3]30025,43180.11.90.07
ReBNet[10]20053,20080.660.11
[31]210290,01280.22050.70
Ours (K-mean)210201,43480.52051.01
Ours (MST)210161,29480.52051.27
+ +Table 5. Hardware performance comparison with the state-of-the-art architectures on CIFAR-10. + +duce the computation cost of binary convolution calculation. To optimize the MST during the training stage, a learning algorithm is proposed. Moreover, we present a hardware implementation for the inference task. Our experimental results demonstrate that the proposed method significantly reduces computation costs while maintaining high accuracy, making it promising for practical applications. + +# 7. Acknowledgements + +This work was supported by the NRF grant funded by the Korea government(MSIT) (No. RS-2023-00207816), and part by IITP Grant funded by MSIT (Artificial Intelligence Innovation Hub) under Grant 2021-0-02068, (No. RS-2022-00155911, AI Convergence Innovation Human Resources Development (Kyung Hee University)), IITP No.2019-0-01287, Evolvable Deep Learning Model Generation Platform for Edge Computing and ITRC support program (IITP-2023-RS-2023-00258649). + +# References + +[1] Richard Bellman. Dynamic programming treatment of the travelling salesman problem. Journal of the ACM (JACM), 9(1):61-63, 1962. 2, 5 +[2] Yoshua Bengio, Nicholas Léonard, and Aaron Courville. Estimating or propagating gradients through stochastic neurons for conditional computation. arXiv preprint arXiv:1308.3432, 2013. 3 +[3] Michaela Blott, Thomas B Preußer, Nicholas J Fraser, Giulio Gambardella, Kenneth O'brien, Yaman Umuroglu, Miriam Leeser, and Kees Vissers. Finn-r: An end-to-end deep-learning framework for fast exploration of quantized neural networks. ACM Transactions on Reconfigurable Technology and Systems (TRETS), 11(3):1-23, 2018. 2, 8, 9 +[4] Adrian Bulat and Georgios Tzimiropoulos. Xnornet++: Improved binary neural networks. arXiv preprint arXiv:1909.13863, 2019. 1, 3, 8 +[5] Zhaowei Cai, Xiaodong He, Jian Sun, and Nuno Vasconcelos. Deep learning with low precision by half-wave gaussian quantization. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5918-5926, 2017. 2 + +[6] Yu-Hsin Chen, Tushar Krishna, Joel S Emer, and Vivienne Sze. Eyeriss: An energy-efficient reconfigurable accelerator for deep convolutional neural networks. IEEE journal of solid-state circuits, 52(1):127-138, 2016. 1 +[7] Matthieu Courbariaux, Itay Hubara, Daniel Soudry, Ran El-Yaniv, and Yoshua Bengio. Binarized neural networks: Training deep neural networks with weights and activations constrained to + 1 or -1. arXiv preprint arXiv:1602.02830, 2016. 1, 2 +[8] Ruizhou Ding, Ting-Wu Chin, Zeye Liu, and Diana Marculescu. Regularizing activation distribution for training binarized deep networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 11408-11417, 2019. 8 +[9] Cheng Fu, Shilin Zhu, Hao Su, Ching-En Lee, and Jishen Zhao. Towards fast and energy-efficient binarized neural network inference on fpga. arXiv preprint arXiv:1810.02068, 2018. 1, 2, 3, 4 +[10] Mohammad Ghasemzadeh, Mohammad Samragh, and Farinaz Koushanfar. Rebnet: Residual binarized neural network. In 2018 IEEE 26th annual international symposium on field-programmable custom computing machines (FCCM), pages 57-64. IEEE, 2018. 2, 8, 9 +[11] Ruihao Gong, Xianglong Liu, Shenghu Jiang, Tianxiang Li, Peng Hu, Jiazhen Lin, Fengwei Yu, and Junjie Yan. Differentiable soft quantization: Bridging full-precision and low-bit neural networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4852–4861, 2019. 8 +[12] Song Han, Huizi Mao, and William J Dally. Deep compression: Compressing deep neural networks with pruning, trained quantization and huffman coding. arXiv preprint arXiv:1510.00149, 2015. 1 +[13] John A Hartigan and Manchek A Wong. Algorithm as 136: A k-means clustering algorithm. Journal of the royal statistical society. series c (applied statistics), 28(1):100-108, 1979. 2, 4 +[14] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 1, 2, 5 +[15] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, et al. Distilling the knowledge in a neural network. arXiv preprint arXiv:1503.02531, 2(7), 2015. 1 +[16] Itay Hubara, Matthieu Courbariaux, Daniel Soudry, Ran El-Yaniv, and Yoshua Bengio. Binarized neural networks. Advances in neural information processing systems, 29, 2016. 8 +[17] Hyeonuk Kim, Jaehyeong Sim, Yeongjae Choi, and Lee-Sup Kim. A kernel decomposition architecture for binary-weight convolutional neural networks. In Proceedings of the 54th Annual Design Automation Conference 2017, pages 1-6, 2017. 1, 3 +[18] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images. 2009. 2 +[19] Dongsoo Lee, Se Jung Kwon, Byeongwook Kim, Yongkwon Jeon, Baeseong Park, and Jeongin Yun. Flexor: Train + +able fractional quantization. Advances in neural information processing systems, 33:1311-1321, 2020. 3 +[20] Mingbao Lin, Rongrong Ji, Zihan Xu, Baochang Zhang, Yan Wang, Yongjian Wu, Feiyue Huang, and Chia-Wen Lin. Rotated binary neural network. Advances in neural information processing systems, 33:7474-7485, 2020. 1, 3, 8 +[21] Xiaofan Lin, Cong Zhao, and Wei Pan. Towards accurate binary convolutional neural network. Advances in neural information processing systems, 30, 2017. 3 +[22] Zechun Liu, Zhiqiang Shen, Marios Savvides, and Kwang-Ting Cheng. Reactnet: Towards precise binary neural network with generalized activation functions. In European conference on computer vision, pages 143-159. Springer, 2020. 1, 3 +[23] Zechun Liu, Baoyuan Wu, Wenhan Luo, Xin Yang, Wei Liu, and Kwang-Ting Cheng. Bi-real net: Enhancing the performance of 1-bit cnns with improved representational capability and advanced training algorithm. In Proceedings of the European conference on computer vision (ECCV), pages 722-737, 2018. 1, 3, 8 +[24] Haotong Qin, Ruihao Gong, Xianglong Liu, Mingzhu Shen, Ziran Wei, Fengwei Yu, and Jingkuan Song. Forward and backward information retention for accurate binary neural networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2250-2259, 2020. 3, 8 +[25] Mohammad Rastegari, Vicente Ordonez, Joseph Redmon, and Ali Farhadi. Xnor-net: Imagenet classification using binary convolutional neural networks. In European conference on computer vision, pages 525-542. Springer, 2016. 1, 3 +[26] Olga Russakovsky, Jia Deng, Hao Su, Jonathan Krause, Sanjeev Satheesh, Sean Ma, Zhiheng Huang, Andrej Karpathy, Aditya Khosla, Michael Bernstein, et al. Imagenet large scale visual recognition challenge. International journal of computer vision, 115(3):211-252, 2015. 2 +[27] Mark Sandler, Andrew Howard, Menglong Zhu, Andrey Zh-moginov, and Liang-Chieh Chen. Mobilenetv2: Inverted residuals and linear bottlenecks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4510-4520, 2018. 1 +[28] Zhijun Tu, Xinghao Chen, Pengju Ren, and Yunhe Wang. Adabin: Improving binary neural networks with adaptive binary sets. In European Conference on Computer Vision, pages 379-395. Springer, 2022. 3, 8 +[29] William Thomas Tutte and William Thomas Tutte. Graph theory, volume 21. Cambridge university press, 2001. 4 +[30] Yaman Umuroglu, Nicholas J Fraser, Giulio Gambardella, Michaela Blott, Philip Leong, Magnus Jahre, and Kees Vissers. Finn: A framework for fast, scalable binarized neural network inference. In Proceedings of the 2017 ACM/SIGDA international symposium on field-programmable gate arrays, pages 65-74, 2017. 1, 2, 8, 9 +[31] Quang Hieu Vo, Ngoc Linh Le, Faaiz Asim, Lok-Won Kim, and Choong Seon Hong. A deep learning accelerator based on a streaming architecture for binary neural networks. IEEE Access, 10:21141-21159, 2022. 1, 2, 3, 4, 5, 6, 8, 9 +[32] Yikai Wang, Yi Yang, Fuchun Sun, and Anbang Yao. Sub-bit neural networks: Learning to compress and accelerate binary + +neural networks. In International Conference on Computer Vision (ICCV), 2021. 1, 2, 3, 8 +[33] Zihan Xu, Mingbao Lin, Jianzhuang Liu, Jie Chen, Ling Shao, Yue Gao, Yonghong Tian, and Rongrong Ji. Recu: Reviving the dead weights in binary neural networks. In Proceedings of the IEEE/CVF international conference on computer vision, pages 5198-5208, 2021. 1, 2, 3, 5, 6, 7, 8 \ No newline at end of file diff --git a/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/images.zip b/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..2414b8ac069c65e634ffa2dc68fcd9fe43f7f051 --- /dev/null +++ b/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:11170037f513c60919cff120e3758be78efaef6d22a3b5d626edd5705b6f12fc +size 558835 diff --git a/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/layout.json b/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..b7c2615bb8ae421330a1744417750456c6c458c2 --- /dev/null +++ b/2023/MST-compression_ Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree/layout.json @@ -0,0 +1,9466 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 65, + 102, + 531, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 102, + 531, + 140 + ], + "spans": [ + { + "bbox": [ + 65, + 102, + 531, + 140 + ], + "type": "text", + "content": "MST-compression: Compressing and Accelerating Binary Neural Networks with Minimum Spanning Tree" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 94, + 161, + 502, + 190 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 94, + 161, + 502, + 190 + ], + "spans": [ + { + "bbox": [ + 94, + 161, + 502, + 190 + ], + "type": "text", + "content": "Quang Hieu Vo, Linh-Tam Tran, Sung-Ho Bae, Lok-Won Kim, Choong Seon Hong* \nDepartment of Computer Science and Engineering, Kyung Hee University" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 164, + 191, + 429, + 202 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 164, + 191, + 429, + 202 + ], + "spans": [ + { + "bbox": [ + 164, + 191, + 429, + 202 + ], + "type": "text", + "content": "{2019310178, tamlt, shbae, lwk, cshong}@khu.ac.kr" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 231, + 192, + 243 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 231, + 192, + 243 + ], + "spans": [ + { + "bbox": [ + 143, + 231, + 192, + 243 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 256, + 290, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 256, + 290, + 568 + ], + "spans": [ + { + "bbox": [ + 47, + 256, + 290, + 568 + ], + "type": "text", + "content": "Binary neural networks (BNNs) have been widely adopted to reduce the computational cost and memory storage on edge-computing devices by using one-bit representation for activations and weights. However, as neural networks become wider/deeper to improve accuracy and meet practical requirements, the computational burden remains a significant challenge even on the binary version. To address these issues, this paper proposes a novel method called Minimum Spanning Tree (MST) compression that learns to compress and accelerate BNNs. The proposed architecture leverages an observation from previous works that an output channel in a binary convolution can be computed using another output channel and XNOR operations with weights that differ from the weights of the reused channel. We first construct a fully connected graph with vertices corresponding to output channels, where the distance between two vertices is the number of different values between the weight sets used for these outputs. Then, the MST of the graph with the minimum depth is proposed to reorder output calculations, aiming to reduce computational cost and latency. Moreover, we propose a new learning algorithm to reduce the total MST distance during training. Experimental results on benchmark models demonstrate that our method achieves significant compression ratios with negligible accuracy drops, making it a promising approach for resource-constrained edge-computing devices." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 590, + 128, + 602 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 590, + 128, + 602 + ], + "spans": [ + { + "bbox": [ + 47, + 590, + 128, + 602 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 611, + 287, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 611, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 611, + 287, + 696 + ], + "type": "text", + "content": "Deep Neural Networks (DNNs) have been widely applied in many artificial intelligence applications, especially vision tasks with high accuracy [27, 14]. However, the cost of computation and massive storage burden is significantly challenging to deploy DNNs on embedded systems such as mobile devices and other resource-constrained platforms. Many approaches have been proposed and demonstrated" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 353, + 228, + 432, + 334 + ], + "blocks": [ + { + "bbox": [ + 353, + 228, + 432, + 334 + ], + "lines": [ + { + "bbox": [ + 353, + 228, + 432, + 334 + ], + "spans": [ + { + "bbox": [ + 353, + 228, + 432, + 334 + ], + "type": "image", + "image_path": "77ff917b2ac1456b9f1df437dd8c7e5f39e49923d42ff58e8ab714152a0b0bb2.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 347, + 547, + 392 + ], + "lines": [ + { + "bbox": [ + 305, + 347, + 547, + 392 + ], + "spans": [ + { + "bbox": [ + 305, + 347, + 547, + 392 + ], + "type": "text", + "content": "Figure 1. Illustration of kernel compression for BNNs with the Kmean method (a) and the shortest Hamiltonian path (b), in which adding red connections can further reduce the computational cost for both of them." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 452, + 228, + 496, + 334 + ], + "blocks": [ + { + "bbox": [ + 452, + 228, + 496, + 334 + ], + "lines": [ + { + "bbox": [ + 452, + 228, + 496, + 334 + ], + "spans": [ + { + "bbox": [ + 452, + 228, + 496, + 334 + ], + "type": "image", + "image_path": "22117411980b0e4eecf7b0650e325a8db2e9a65a0a3cd171a9daa7aa640e7857.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 399, + 545, + 484 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 399, + 545, + 484 + ], + "spans": [ + { + "bbox": [ + 304, + 399, + 545, + 484 + ], + "type": "text", + "content": "their effectiveness in reducing energy and resources while maintaining the deep models' accuracy, including pruning [12], quantization [7], distillation [15], and efficient hardware implementation [6]. Among these methods, quantization with less bit-width for parameter and activation representation is widely used due to its great benefits and possibility in most practical applications." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 484, + 546, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 484, + 546, + 640 + ], + "spans": [ + { + "bbox": [ + 304, + 484, + 546, + 640 + ], + "type": "text", + "content": "Binarized neural network is a particular form of the quantization method in which weight values and activations are converted to 1-bit values. Accordingly, multiplications and accumulation operations can be replaced by XNOR and Popcount operations [7], respectively. In addition, batch normalization is simplified to a threshold comparison [31], while the pooling can be performed with OR operations [30]. Consequently, the compression ratio on memory storage and computational cost is significantly improved, leading to remarkable performance acceleration. Nevertheless, the accuracy degradation is the trade-off of minimizing the bit-width as BNN. Thus, most previous works focus on reducing this accuracy gap [25, 4, 33, 22, 20, 33, 23]." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "text", + "content": "Meanwhile, compressing BNNs has not received much attention, with only a few prominent methods [32, 9, 31, 17], where the kernel compression [9, 31] gives impressive results with roughly " + }, + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "text", + "content": " resources reduction. In particular, given a binary convolution, inspired by an observation that an output channel can be calculated using another out" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 702, + 137, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 137, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 137, + 712 + ], + "type": "text", + "content": "*Corresponding Author" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 295, + 748, + 314, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 758 + ], + "type": "text", + "content": "6091" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 370 + ], + "type": "text", + "content": "put channel and outputs of XNOR operations using weights that respectively differ from the reused channel's weights [9], authors in [31, 9] proposed to construct a fully connected graph, in which each vertex corresponds to an output channel, and distance between two vertices is the number of different values between two weight sets used for the two output channels. Then, based on the graph, they use the K-mean cluster and shortest Hamiltonian path to reorder the convolution output calculation, aiming to reduce the number of XNOR operations. However, these approaches have yet to fully minimize the computational cost as output channels can use less computation. Indeed, Figure 1 (a) illustrates an example of the K-mean method, where two vertices are considered centers of two groups. Two output channels corresponding to centers are fully calculated1, while other vertices reuse their centers for calculation. However, adding a connection between the two centers would enable one to utilize the rest with less computation cost. Additionally, in the shortest Hamiltonian path shown in Figure 1 (b), there may exist a connection to a specific vertex that is shorter than the connection from the preceding vertex in the path, leading to a lower required number of operations for this vertex. Furthermore, time complexity poses a challenge in these methods [1, 13], resulting in longer exploration times." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 371, + 289, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 371, + 289, + 552 + ], + "spans": [ + { + "bbox": [ + 46, + 371, + 289, + 552 + ], + "type": "text", + "content": "To more effectively minimize the number of XNOR operations with the mentioned observation, in all connections to a specific vertex, the minimum connection must be selected to minimize the computation cost for this vertex. In addition, all of these selected connections must be included in a subgraph that visits all vertices exactly once to ensure that only one output channel is fully calculated. As a result, a MST is the only structure that can fulfill these requirements. Therefore, this paper leverages the MST to reorder binary convolution output calculations. Figure 2 shows a simple example of reordering calculation on a convolution. In this example, only the output channel 4 is fully calculated with " + }, + { + "bbox": [ + 46, + 371, + 289, + 552 + ], + "type": "inline_equation", + "content": "C_{in} \\times M \\times M" + }, + { + "bbox": [ + 46, + 371, + 289, + 552 + ], + "type": "text", + "content": " bit-weight values. In contrast, other channels are calculated using output channel 4, following the MST direction." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 552, + 289, + 672 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 552, + 289, + 672 + ], + "spans": [ + { + "bbox": [ + 46, + 552, + 289, + 672 + ], + "type": "text", + "content": "On the other hand, to maximize the advantages of the MST, we further minimize the MST distance of all convolution layers with a new learning algorithm right during the training stage. Besides, we propose a hardware accelerator for BNNs applying the MST compression to demonstrate the feasibility and effectiveness of the method related to hardware resources. To the best of our knowledge, this method gives the highest compression ratio with implementation from learning for compression to acceleration. In summary, the following are contributions of this paper:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 58, + 681, + 288, + 694 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 681, + 288, + 694 + ], + "spans": [ + { + "bbox": [ + 58, + 681, + 288, + 694 + ], + "type": "text", + "content": "- We introduce and analyze the effectiveness of the MST" + } + ] + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 314, + 71, + 545, + 190 + ], + "blocks": [ + { + "bbox": [ + 314, + 71, + 545, + 190 + ], + "lines": [ + { + "bbox": [ + 314, + 71, + 545, + 190 + ], + "spans": [ + { + "bbox": [ + 314, + 71, + 545, + 190 + ], + "type": "image", + "image_path": "ffb0d321e668f307b83d20e2ce2aaf7a50bcf960cbe5a2f54c32cc9606afaee8.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 203, + 547, + 248 + ], + "lines": [ + { + "bbox": [ + 305, + 203, + 547, + 248 + ], + "spans": [ + { + "bbox": [ + 305, + 203, + 547, + 248 + ], + "type": "text", + "content": "Figure 2. The process of arranging the order of computation on a binary convolution layer, in which output channel 4 is fully calculated first. Then, the output channel 4 is used to calculate channel 1, channel 2 and channel 3." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 324, + 268, + 545, + 292 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 324, + 268, + 545, + 292 + ], + "spans": [ + { + "bbox": [ + 324, + 268, + 545, + 292 + ], + "type": "text", + "content": "in reducing the computational cost for the inference on a binary convolution layer." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 300, + 545, + 406 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 317, + 300, + 545, + 350 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 300, + 545, + 350 + ], + "spans": [ + { + "bbox": [ + 317, + 300, + 545, + 350 + ], + "type": "text", + "content": "- We propose a training algorithm that can reduce the MST distance and depth right during the training process, which consequently maximizes the compression ratio for inference implementation." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 358, + 545, + 406 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 358, + 545, + 406 + ], + "spans": [ + { + "bbox": [ + 317, + 358, + 545, + 406 + ], + "type": "text", + "content": "- We provide the corresponding hardware acceleration for the proposed method with high throughput and better resource efficiency, compared to related works [3, 30, 31, 10]." + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 304, + 418, + 545, + 586 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 418, + 545, + 586 + ], + "spans": [ + { + "bbox": [ + 304, + 418, + 545, + 586 + ], + "type": "text", + "content": "The experiments are performed for BNNs including VGG-small [5], ResNet-18/20 [14] on CIFAR-10 dataset [18], and ResNet-18/34 [14] on ImageNet [26]. The results show that the proposed approach gives a higher compression ratio than the previous works [32]. Compared to the baseline [33], our method reduces up to " + }, + { + "bbox": [ + 304, + 418, + 545, + 586 + ], + "type": "inline_equation", + "content": "13.5 \\times" + }, + { + "bbox": [ + 304, + 418, + 545, + 586 + ], + "type": "text", + "content": " the convolution parameters and " + }, + { + "bbox": [ + 304, + 418, + 545, + 586 + ], + "type": "inline_equation", + "content": "5.51 \\times" + }, + { + "bbox": [ + 304, + 418, + 545, + 586 + ], + "type": "text", + "content": " bit-wise operations on the same model with an acceptable accuracy degradation. Regarding hardware acceleration, we conduct the experiments for a BNN with the same structure as the baseline [31] and apply the proposed approach. Compared to the baseline [31], hardware deployments demonstrate that BNNs with our method save " + }, + { + "bbox": [ + 304, + 418, + 545, + 586 + ], + "type": "inline_equation", + "content": "1.8 \\times" + }, + { + "bbox": [ + 304, + 418, + 545, + 586 + ], + "type": "text", + "content": " LUTs, and " + }, + { + "bbox": [ + 304, + 418, + 545, + 586 + ], + "type": "inline_equation", + "content": "1.81 \\times" + }, + { + "bbox": [ + 304, + 418, + 545, + 586 + ], + "type": "text", + "content": " area efficiency while maintaining the acceleration speed and accuracy." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 597, + 392, + 609 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 597, + 392, + 609 + ], + "spans": [ + { + "bbox": [ + 306, + 597, + 392, + 609 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 617, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 545, + 715 + ], + "type": "text", + "content": "Training neural networks with binary weights and activations were first introduced by Coubariaux et al. [7] and then rapidly gained attention from the community due to the high compression ratio. However, accuracy drop is a critical problem of this direction, while compression is still highly demanded. Various techniques are proposed to further compress and improve accuracy based on the binary property." + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 58, + 702, + 264, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 264, + 713 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 264, + 713 + ], + "type": "inline_equation", + "content": "{}^{1}" + }, + { + "bbox": [ + 58, + 702, + 264, + 713 + ], + "type": "text", + "content": " calculated with " + }, + { + "bbox": [ + 58, + 702, + 264, + 713 + ], + "type": "inline_equation", + "content": "{C}_{in} \\times M \\times M" + }, + { + "bbox": [ + 58, + 702, + 264, + 713 + ], + "type": "text", + "content": " XNORs,denoted in Figure 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6092" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 360 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 360 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 360 + ], + "type": "text", + "content": "For accuracy improvement, Rastegari et al. [25] proposed adding a scaling factor to the convolution to reduce the quantization error. To generalize this idea aiming to enhance accuracy, the authors in [4] extended this factor dimension and enabled its training option as a learnable parameter. Besides, instead of using the Straight Through Estimation (STE) method [2], Liu et al. [23], and Lin et al. [20] proposed using a piece-wise linear and training-aware approximation function, respectively, to approximate the sign function gradient better. Meanwhile, some previous works introduced both new optimization techniques and corresponding BNN to shrink the accuracy gap entirely [22, 21, 28, 24]. For example, based on Bi-real Net in [23], authors in [22] proposed new sign and activation functions to shift and reshape activation distribution with a new baseline neural network model that can boost the performance. Other works look at the binary characteristics from deeper perspectives to limit information loss [20, 28, 33]. For example, KL divergence is employed in [28] to minimize the difference between the distribution of binary and real-weight counterparts. Xu et al. [33] observed the low probability of changing large full-precision weight when binarizing and proposed the ReCu function to revive the death weights, leading to lower quantization error." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 364, + 289, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 364, + 289, + 544 + ], + "spans": [ + { + "bbox": [ + 46, + 364, + 289, + 544 + ], + "type": "text", + "content": "Binary model compression has received less attention as only a few techniques have been proposed so far. Specifically, Lee et al. [19] proposed an encryption algorithm to compress binary weights with lower than 1-bit per weight, and XOR-gate networks are used to decrypt the inference task. Similarly, Sub-bit Neural Networks (SNN) [32] proposed using lower than 9 bits for each " + }, + { + "bbox": [ + 46, + 364, + 289, + 544 + ], + "type": "inline_equation", + "content": "3 \\times 3" + }, + { + "bbox": [ + 46, + 364, + 289, + 544 + ], + "type": "text", + "content": " binary kernel based on the scattered 9-bit kernel distribution. Other proposed compression methods provided only hardware techniques for inference implementation. Authors in [31, 9] proposed BNN hardware architectures using weight/input reuse with different calculation orders for convolution to reduce hardware overhead. Kim et al. [17] introduces kernel decomposition that can reduce the computational cost by sharing one base output for all channels." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 568, + 126, + 582 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 568, + 126, + 582 + ], + "spans": [ + { + "bbox": [ + 47, + 568, + 126, + 582 + ], + "type": "text", + "content": "3. Background" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "text", + "content": "This section briefly describes how to construct a binary convolution layer and the related optimization methods. For a convolution layer with " + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "C_{in}" + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "text", + "content": " input channels, " + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "C_{out}" + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "text", + "content": " output channels, and kernel size " + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "text", + "content": ", weights and activations are denoted by " + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{W}^r \\in \\mathbb{R}^n" + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "A^r \\in \\mathbb{R}^m" + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "n = C_{out} \\times C_{in} \\times M \\times M" + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "m = C_{in} \\times W_{in} \\times H_{in}" + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "W_{in} \\times H_{in}" + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "text", + "content": " represents input feature map size. To simplify the computation and reduce memory storage, in a binary convolution layer, the binarization of activations " + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{A}^b \\in \\{\\pm 1\\}^m" + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "text", + "content": " and weights " + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{W}^b \\in \\{\\pm 1\\}^n" + }, + { + "bbox": [ + 47, + 594, + 289, + 715 + ], + "type": "text", + "content": " is acquired by the fol" + } + ] + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 313, + 72, + 542, + 250 + ], + "blocks": [ + { + "bbox": [ + 313, + 72, + 542, + 250 + ], + "lines": [ + { + "bbox": [ + 313, + 72, + 542, + 250 + ], + "spans": [ + { + "bbox": [ + 313, + 72, + 542, + 250 + ], + "type": "image", + "image_path": "0934753088b843d1756c7c6c4408910c4840ba22359ed9e9593ef8fbde5a8cd0.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 264, + 547, + 309 + ], + "lines": [ + { + "bbox": [ + 304, + 264, + 547, + 309 + ], + "spans": [ + { + "bbox": [ + 304, + 264, + 547, + 309 + ], + "type": "text", + "content": "Figure 3. Weight-reuse method description. Here, the red line is counting the number of elements, the green line is summing all elements. " + }, + { + "bbox": [ + 304, + 264, + 547, + 309 + ], + "type": "inline_equation", + "content": "P_{12}" + }, + { + "bbox": [ + 304, + 264, + 547, + 309 + ], + "type": "text", + "content": " is " + }, + { + "bbox": [ + 304, + 264, + 547, + 309 + ], + "type": "inline_equation", + "content": "\\sum_{j=1}^{d_{12}} \\mathrm{XNOR}(\\mathcal{A}_{2j}, \\mathcal{W}_{2j})" + }, + { + "bbox": [ + 304, + 264, + 547, + 309 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 264, + 547, + 309 + ], + "type": "inline_equation", + "content": "Y_{2}" + }, + { + "bbox": [ + 304, + 264, + 547, + 309 + ], + "type": "text", + "content": " is " + }, + { + "bbox": [ + 304, + 264, + 547, + 309 + ], + "type": "inline_equation", + "content": "2(P_{1} - d_{12} + 2P_{12}) - C_{in} \\times M \\times M" + }, + { + "bbox": [ + 304, + 264, + 547, + 309 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 306, + 316, + 414, + 327 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 316, + 414, + 327 + ], + "spans": [ + { + "bbox": [ + 306, + 316, + 414, + 327 + ], + "type": "text", + "content": "lowing sign function [25]," + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 349, + 333, + 545, + 365 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 349, + 333, + 545, + 365 + ], + "spans": [ + { + "bbox": [ + 349, + 333, + 545, + 365 + ], + "type": "interline_equation", + "content": "x ^ {b} = \\operatorname {S i g n} (x) = \\left\\{ \\begin{array}{l} + 1, \\text {i f} x \\geq 0, \\\\ - 1, \\text {o t h e r w i s e .} \\end{array} \\right. \\tag {1}", + "image_path": "258d46c4f9f79ea16306d599a4533dccfd0460b068fd878d1cf8087c1aff1600.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 372, + 547, + 409 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 372, + 547, + 409 + ], + "spans": [ + { + "bbox": [ + 304, + 372, + 547, + 409 + ], + "type": "text", + "content": "If " + }, + { + "bbox": [ + 304, + 372, + 547, + 409 + ], + "type": "inline_equation", + "content": "-1" + }, + { + "bbox": [ + 304, + 372, + 547, + 409 + ], + "type": "text", + "content": " is substituted by 0 to represent a negative value for " + }, + { + "bbox": [ + 304, + 372, + 547, + 409 + ], + "type": "inline_equation", + "content": "\\mathcal{A}^b" + }, + { + "bbox": [ + 304, + 372, + 547, + 409 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 372, + 547, + 409 + ], + "type": "inline_equation", + "content": "\\mathcal{W}^b" + }, + { + "bbox": [ + 304, + 372, + 547, + 409 + ], + "type": "text", + "content": ", the output convolution operation of the " + }, + { + "bbox": [ + 304, + 372, + 547, + 409 + ], + "type": "inline_equation", + "content": "i^{th}" + }, + { + "bbox": [ + 304, + 372, + 547, + 409 + ], + "type": "text", + "content": " channel now is reformulated as in Eq. (2) [31]." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 415, + 545, + 459 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 415, + 545, + 459 + ], + "spans": [ + { + "bbox": [ + 306, + 415, + 545, + 459 + ], + "type": "interline_equation", + "content": "Y _ {i} = (2 \\sum_ {j = 1} ^ {C _ {i n} M M} \\operatorname {X N O R} \\left(\\mathcal {A} _ {i j} ^ {b}, \\mathcal {W} _ {i j} ^ {b}\\right) - C _ {i n} \\times M \\times M) \\odot \\alpha , \\tag {2}", + "image_path": "45317d5aef9c808271ff03a34a2f48730807e51610d212cc7c3aefbff3d17be2.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "spans": [ + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "type": "inline_equation", + "content": "\\sum_{1}^{C_{in}\\times M\\times M}\\mathrm{XNOR}(\\mathcal{A}_{ij}^{b},\\mathcal{W}_{ij}^{b})" + }, + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "type": "text", + "content": " is the number of set-bits (Popcount) of the output channel " + }, + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "type": "inline_equation", + "content": "i^{th}" + }, + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "type": "inline_equation", + "content": "\\odot" + }, + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "type": "text", + "content": " is the element-wise multiplication, and " + }, + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "type": "inline_equation", + "content": "C_{in}\\times M\\times M" + }, + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "type": "text", + "content": " is the number of bit-wise XNOR operations used to calculate one output channel. The scaling factor " + }, + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 457, + 547, + 579 + ], + "type": "text", + "content": " is added as a learnable parameter to lessen quantization error [25]. For backward propagation, following [23], the STE [2] method is used for the approximation gradient on weights, while the piecewise polynomial function [23] is used for gradient approximation on activations." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": "To further compress the BNN models, in this paper, we apply the weight reuse method [31] for the inference task. Accordingly, given the " + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "inline_equation", + "content": "l^{th}" + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": " binary convolution, as shown in Figure 3, we denote " + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "inline_equation", + "content": "P_{i}" + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "inline_equation", + "content": "P_{j}" + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": " as the output of the Popcount operations of the output channels " + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "inline_equation", + "content": "i^{th}" + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "inline_equation", + "content": "j^{th}" + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": ", respectively. All binary weights of the layer are divided into " + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "inline_equation", + "content": "C_{out}" + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": " weight sets " + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "inline_equation", + "content": "w_{b}^{li} \\in \\{\\pm 1\\}^{C_{in} \\times M \\times M}" + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "inline_equation", + "content": "i = 1,2,\\dots,C_{out}" + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": " and each weight set is used to calculate for an output channel. " + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "inline_equation", + "content": "d_{ij}" + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": " is the number of weight bits in the " + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "inline_equation", + "content": "w_{b}^{li}" + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": " that differ from the " + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "inline_equation", + "content": "w_{b}^{lj}" + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": ", compared one-to-one respectively. " + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "inline_equation", + "content": "P_{ij}" + }, + { + "bbox": [ + 304, + 580, + 547, + 715 + ], + "type": "text", + "content": " is the sum of XNOR operations with the" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6093" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 71, + 286, + 418 + ], + "blocks": [ + { + "bbox": [ + 51, + 71, + 286, + 418 + ], + "lines": [ + { + "bbox": [ + 51, + 71, + 286, + 418 + ], + "spans": [ + { + "bbox": [ + 51, + 71, + 286, + 418 + ], + "type": "image", + "image_path": "b54dd59fcb9bd5ed24a2c6fd3f40c58b51efc81a0a552c82bdb14eb601b0346e.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 429, + 289, + 495 + ], + "lines": [ + { + "bbox": [ + 46, + 429, + 289, + 495 + ], + "spans": [ + { + "bbox": [ + 46, + 429, + 289, + 495 + ], + "type": "text", + "content": "Figure 4. Comparison between the computation process of a standard binary convolution and our method in BNN acceleration. Instead of fully computing all " + }, + { + "bbox": [ + 46, + 429, + 289, + 495 + ], + "type": "inline_equation", + "content": "C_{in} \\times M \\times M" + }, + { + "bbox": [ + 46, + 429, + 289, + 495 + ], + "type": "text", + "content": " XNOR operations for each layer, our method provides an optimal order of the calculation using the MST to minimize the number of XNOR operations and total parameters." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 498, + 288, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 498, + 288, + 536 + ], + "spans": [ + { + "bbox": [ + 46, + 498, + 288, + 536 + ], + "type": "text", + "content": "weights of the channel " + }, + { + "bbox": [ + 46, + 498, + 288, + 536 + ], + "type": "inline_equation", + "content": "j^{th}" + }, + { + "bbox": [ + 46, + 498, + 288, + 536 + ], + "type": "text", + "content": " that differ from the " + }, + { + "bbox": [ + 46, + 498, + 288, + 536 + ], + "type": "inline_equation", + "content": "i^{th}" + }, + { + "bbox": [ + 46, + 498, + 288, + 536 + ], + "type": "text", + "content": " counterpart. To calculate the output channel " + }, + { + "bbox": [ + 46, + 498, + 288, + 536 + ], + "type": "inline_equation", + "content": "j^{th}" + }, + { + "bbox": [ + 46, + 498, + 288, + 536 + ], + "type": "text", + "content": " from the output channel " + }, + { + "bbox": [ + 46, + 498, + 288, + 536 + ], + "type": "inline_equation", + "content": "i^{th}" + }, + { + "bbox": [ + 46, + 498, + 288, + 536 + ], + "type": "text", + "content": ", we use Eq. (3)." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 77, + 544, + 287, + 559 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 77, + 544, + 287, + 559 + ], + "spans": [ + { + "bbox": [ + 77, + 544, + 287, + 559 + ], + "type": "interline_equation", + "content": "Y _ {j} = 2 \\left(P _ {i} - d _ {i j} + 2 P _ {i j}\\right) - C _ {i n} \\times M \\times M. \\tag {3}", + "image_path": "d8cd287b21c502709093b19ae992163419c416dcd1cccff811025a073c06d61a.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 567, + 130, + 581 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 567, + 130, + 581 + ], + "spans": [ + { + "bbox": [ + 47, + 567, + 130, + 581 + ], + "type": "text", + "content": "4. Methodology" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 587, + 287, + 601 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 587, + 287, + 601 + ], + "spans": [ + { + "bbox": [ + 47, + 587, + 287, + 601 + ], + "type": "text", + "content": "4.1. Minimum Spanning Tree for BNN Acceleration" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "text", + "content": "For a binary convolution layer, we construct a fully connected graph in which each vertex corresponds to an output channel. The distance between two vertices " + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "text", + "content": " is " + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "inline_equation", + "content": "d_{ij}" + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "text", + "content": ". As shown in Eq. (3), an output channel " + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "text", + "content": " can be calculated via the Popcount of an output channel " + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "text", + "content": " and the Popcount of " + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "inline_equation", + "content": "d_{ij}" + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "text", + "content": " XNOR operations. That means the number of XNOR operations executed for the output channel " + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "text", + "content": " is the distance " + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "inline_equation", + "content": "d_{ij}" + }, + { + "bbox": [ + 46, + 605, + 288, + 713 + ], + "type": "text", + "content": ". Based on this observation, to minimize the number of XNOR operations used for all out" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "text", + "content": "put channels, we need a sub-graph that includes all vertices with the minimum total edge distances, which is named an MST [29]. Returning to the example in Figure 2, Figure 4 illustrates the computation process of this convolution example with the standard and proposed approach. Specifically, in the standard direction, each output channel needs 9 XNOR operations, while in our direction, only the " + }, + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "inline_equation", + "content": "4^{th}" + }, + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "text", + "content": " output channel is fully computed by 9 XNOR operations, and the " + }, + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "inline_equation", + "content": "1^{st}, 2^{nd}, 3^{rd}" + }, + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "text", + "content": " output channels reuse the output channel " + }, + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "inline_equation", + "content": "4^{th}" + }, + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "text", + "content": " with 2, 3, 2 XNOR operations, respectively. Accordingly, the compression ratio for this example is " + }, + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "inline_equation", + "content": "(2 + 3 + 2 + 3 \\times 3) / (4 \\times 1 \\times 3 \\times 3) = 0.44" + }, + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "text", + "content": ". In general, we can reduce the computational cost for a convolution layer with the following ratio:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 348, + 246, + 545, + 277 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 348, + 246, + 545, + 277 + ], + "spans": [ + { + "bbox": [ + 348, + 246, + 545, + 277 + ], + "type": "interline_equation", + "content": "\\mathcal {R} = \\frac {\\sum_ {j \\neq r o o t} ^ {C _ {o u t}} d _ {i j} + C _ {i n} \\times M \\times M}{C _ {o u t} \\times C _ {i n} \\times M \\times M}, \\tag {4}", + "image_path": "f4610ea85532f9b2df9a854ed73bef5dff8857bd76a79b30278aa6a5b69c3b1c.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 281, + 545, + 305 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 281, + 545, + 305 + ], + "spans": [ + { + "bbox": [ + 304, + 281, + 545, + 305 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 281, + 545, + 305 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 281, + 545, + 305 + ], + "type": "text", + "content": " is the parent of the vertex " + }, + { + "bbox": [ + 304, + 281, + 545, + 305 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 304, + 281, + 545, + 305 + ], + "type": "text", + "content": ". If " + }, + { + "bbox": [ + 304, + 281, + 545, + 305 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 304, + 281, + 545, + 305 + ], + "type": "text", + "content": " is the root of the MST, this output uses " + }, + { + "bbox": [ + 304, + 281, + 545, + 305 + ], + "type": "inline_equation", + "content": "C_{in} \\times M \\times M" + }, + { + "bbox": [ + 304, + 281, + 545, + 305 + ], + "type": "text", + "content": " binary weight values." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 306, + 545, + 389 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 306, + 545, + 389 + ], + "spans": [ + { + "bbox": [ + 304, + 306, + 545, + 389 + ], + "type": "text", + "content": "Regarding parameters, because the streaming architecture described in Sec. 4.3 is fully implemented with all layers on the FPGA platform, weights' locations can be converted to connections from inputs to the correct XNORs and corresponding weight values at the circuit level. Thus, our proposed method counts only the parameters we need for XNOR logic gates, as shown in Figure 4." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 389, + 545, + 473 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 389, + 545, + 473 + ], + "spans": [ + { + "bbox": [ + 304, + 389, + 545, + 473 + ], + "type": "text", + "content": "Number of bit-wise operations. Compared with the previous approaches [31, 9], in a binary convolution layer, the proposed method can better reduce the number of XNORs and parameters. Firstly, as explained in the previous section, adding connections among centers leads to less computation for the K-mean approach [31] as in Eq. (5)." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 310, + 477, + 545, + 504 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 477, + 545, + 504 + ], + "spans": [ + { + "bbox": [ + 310, + 477, + 545, + 504 + ], + "type": "interline_equation", + "content": "\\sum_ {j} d _ {i j} + C _ {i n} \\times M \\times M < \\sum_ {j \\notin C} d _ {i j} + R \\times C _ {i n} \\times M \\times M, \\tag {5}", + "image_path": "743607789f26dabc536beb0237d63d0cd461ce9d4cf2bac23093eee021e514d6.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 510, + 545, + 629 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 510, + 545, + 629 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 545, + 629 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 510, + 545, + 629 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 304, + 510, + 545, + 629 + ], + "type": "text", + "content": " includes all centers, " + }, + { + "bbox": [ + 304, + 510, + 545, + 629 + ], + "type": "inline_equation", + "content": "R" + }, + { + "bbox": [ + 304, + 510, + 545, + 629 + ], + "type": "text", + "content": " is the number of centers. Furthermore, adding connections among centers also creates a spanning tree, whose computational cost is always equal to or higher than using an MST. Secondly, in [9], the authors proposed using the shortest Hamiltonian path to arrange the computation order. Because this path visits all vertices exactly once, the shortest Hamiltonian path is also a spanning tree. Therefore, the number of XNOR bit-wise operations using an MST method is equal to or lower than the shortest Hamiltonian path." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "text", + "content": "Exploration time. The MST is faster and less complex for finding the computation order, compared to previous work [9, 31]. Indeed, the MST is found by Prim's algorithm with the complexity of " + }, + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "inline_equation", + "content": "O(V^2)" + }, + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "text", + "content": " [29], where " + }, + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "inline_equation", + "content": "V" + }, + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "text", + "content": " is the number of vertices. In contrast, the K-mean algorithm requires " + }, + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "inline_equation", + "content": "O(V^2 G)" + }, + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "text", + "content": " [13] time complexity, where " + }, + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "inline_equation", + "content": "G" + }, + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "text", + "content": " denotes the number of groups. Since the optimal number of groups varies" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6094" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 71, + 70, + 265, + 205 + ], + "blocks": [ + { + "bbox": [ + 71, + 70, + 265, + 205 + ], + "lines": [ + { + "bbox": [ + 71, + 70, + 265, + 205 + ], + "spans": [ + { + "bbox": [ + 71, + 70, + 265, + 205 + ], + "type": "image", + "image_path": "921cf3b22ea120edb42a983200a658268c1be835f1007d23d06cee503cfd5235.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 213, + 289, + 248 + ], + "lines": [ + { + "bbox": [ + 46, + 213, + 289, + 248 + ], + "spans": [ + { + "bbox": [ + 46, + 213, + 289, + 248 + ], + "type": "text", + "content": "Figure 5. a) The computation tree's depth using the K-mean cluster. b) The computation tree's depth using the shortest Hamiltonian path. c) The computation tree's depth using the MST." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 51, + 258, + 284, + 337 + ], + "blocks": [ + { + "bbox": [ + 51, + 258, + 284, + 337 + ], + "lines": [ + { + "bbox": [ + 51, + 258, + 284, + 337 + ], + "spans": [ + { + "bbox": [ + 51, + 258, + 284, + 337 + ], + "type": "table", + "html": "
LHamiltonianK-meanMST
Bit-OpsTimeBit-OpsTimeBit-OpsTime
11.08 M31.3 s1.33 M0.090 s1.07 M0.021 s
21.09 M32.9 s1.30 M0.075 s1.06 M0.021 s
31.07 M32.6 s1.30 M0.085 s1.05 M0.023 s
41.10 M32.7 s1.33 M0.076 s1.08 M0.021 s
51.11 M32.5 s1.32 M0.115 s1.09 M0.020 s
61.09 M32.5 s1.33 M0.086 s1.08 M0.021 s
", + "image_path": "8f4d2c7c1776d88729a813df000fe78ef8b4c8f3f640fa844e90bc7a2cabfae3.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 344, + 288, + 378 + ], + "lines": [ + { + "bbox": [ + 46, + 344, + 288, + 378 + ], + "spans": [ + { + "bbox": [ + 46, + 344, + 288, + 378 + ], + "type": "text", + "content": "Table 1. Bit-Ops and running time w.r.t. different approaches for reordering calculation on the first 6 convolution layers of ResNet20 with 16 output channels." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 390, + 287, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 390, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 46, + 390, + 287, + 533 + ], + "type": "text", + "content": "across convolutions, extra time is needed to determine this number for each case. Meanwhile, the shortest Hamiltonian path has a much higher time complexity of " + }, + { + "bbox": [ + 46, + 390, + 287, + 533 + ], + "type": "inline_equation", + "content": "O(V^{2}2^{V})" + }, + { + "bbox": [ + 46, + 390, + 287, + 533 + ], + "type": "text", + "content": " [1], making it challenging to apply in practical settings. To estimate these approaches for practical operation, we perform experiments for the first 6 binary convolution layers of ResNet-20 [14] with the weight data trained by [33], while experiments on deeper layers with a larger number of output channels are infeasible even uncompleted for the K-mean and the shortest Hamiltonian path approach due to their longer running times. According to Table 1, the MST approach gives the lowest bit-Ops and exploration time." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 534, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 534, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 534, + 288, + 714 + ], + "type": "text", + "content": "Computation latency. This is one of the factors affecting the resource overhead. This paper focuses on improving the architecture in [31], a streaming acceleration for BNNs. In doing so, the deeper the computation tree, the longer latency between the time output of the first and the last channel comes out. Consequently, the number of added registers (Flip-flops) for synchronization tends to be equal or more for the deeper tree because all output channels must be available at the same clock for the next convolution operation. The exact number of added registers depends on the number of adders executed in a clock period, which is affected by the required frequency, design complexity, and hardware platform. Thus, to evaluate the comprehensive effects of the depth with practical implementations, the experiments related to this comparison are provided in Sec. 5." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 72, + 547, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 228 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 228 + ], + "type": "text", + "content": "Figure 5 visually describes the depth of the MST, K-mean cluster, and the shortest Hamiltonian path approach. Accordingly, the depths of the K-mean method and the shortest Hamiltonian path are always 1 and " + }, + { + "bbox": [ + 304, + 72, + 547, + 228 + ], + "type": "inline_equation", + "content": "V" + }, + { + "bbox": [ + 304, + 72, + 547, + 228 + ], + "type": "text", + "content": ", respectively. Meanwhile, the MST's depth can range from 1 to " + }, + { + "bbox": [ + 304, + 72, + 547, + 228 + ], + "type": "inline_equation", + "content": "V" + }, + { + "bbox": [ + 304, + 72, + 547, + 228 + ], + "type": "text", + "content": ", depending on the graph structure. Therefore, the proposed method is always better than the shortest Hamiltonian path in all aspects (number of operations, latency, running time). Meanwhile, the K-mean method gives a better latency but much worse for the rest. After exploring an MST for the posttraining stage to limit the impact of the tree depth on latency and resources, we continue finding a new root that makes the depth of the new tree minimum." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 235, + 437, + 248 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 235, + 437, + 248 + ], + "spans": [ + { + "bbox": [ + 305, + 235, + 437, + 248 + ], + "type": "text", + "content": "4.2. Learning Optimization" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "spans": [ + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "text", + "content": "According to the observation mentioned earlier, to enhance the benefits of the MST approach, we propose a simple learning method that can further reduce the MST depth and total MST distance over a BNN model. Specifically, to make the training converged, instead of directly optimizing the MST, we cluster weight sets " + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "inline_equation", + "content": "(\\mathrm{w}_b^{li})" + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "text", + "content": " to different groups and try to reduce the distance among weight sets in each group by optimizing the distances from all weight sets to fixed centers. In doing so, given the " + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "inline_equation", + "content": "l^{th}" + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "text", + "content": " binary convolution layer of a BNN model, we first randomly sample a binary center subset " + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "inline_equation", + "content": "\\mathbb{C}_l \\subset \\{\\pm 1\\}^{C_{in} \\times M \\times M}" + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "inline_equation", + "content": "|\\mathbb{C}_l| = N_l" + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "text", + "content": ". Then, we explore the nearest center in " + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "inline_equation", + "content": "\\mathbb{C}_l" + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "text", + "content": " for every " + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "inline_equation", + "content": "\\mathrm{w}_b^{li}" + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "text", + "content": " and save it into a dictionary " + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "inline_equation", + "content": "\\mathcal{C}" + }, + { + "bbox": [ + 304, + 254, + 547, + 410 + ], + "type": "text", + "content": " using Eq. (6)." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 313, + 415, + 545, + 449 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 313, + 415, + 545, + 449 + ], + "spans": [ + { + "bbox": [ + 313, + 415, + 545, + 449 + ], + "type": "interline_equation", + "content": "\\mathcal {C} \\left(\\mathrm {w} _ {b} ^ {l i}\\right) = \\underset {x} {\\operatorname {a r g m i n}} \\left(\\sum_ {i = 1} ^ {C _ {i n} \\times M \\times M} \\| x - \\mathrm {w} _ {b} ^ {l i} \\|\\right); x \\in \\mathbb {C} _ {l}. \\tag {6}", + "image_path": "a107633c07f11bb5421d75ee2385b631c61db44dabecf3d42bea8f662563e190.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 456, + 547, + 649 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 456, + 547, + 649 + ], + "spans": [ + { + "bbox": [ + 304, + 456, + 547, + 649 + ], + "type": "text", + "content": "On the other hand, the total distance from every weight sets to its center is added to the loss function and compels the training to minimize both the cross-entropy loss and the distance among weight sets in a group (distance loss). To strike a balance between optimizing the original and distance loss, we adjust a hyper-parameter " + }, + { + "bbox": [ + 304, + 456, + 547, + 649 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 456, + 547, + 649 + ], + "type": "text", + "content": " to achieve an optimal ratio for different BNN models. Besides, a " + }, + { + "bbox": [ + 304, + 456, + 547, + 649 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 304, + 456, + 547, + 649 + ], + "type": "text", + "content": " parameter serves as a hyper-parameter to control the priority of the original and additional loss during the training. This parameter varies following a specific scheduler during the training process. Particularly, the algorithm prioritizes reducing the MST distance and depth during the initial training phase and gradually shifting its focus toward accuracy at the end of the process. The new loss function is shown in Eq. (7), where " + }, + { + "bbox": [ + 304, + 456, + 547, + 649 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_0(\\mathrm{input},\\mathrm{w})" + }, + { + "bbox": [ + 304, + 456, + 547, + 649 + ], + "type": "text", + "content": " is the original loss function. Forward processes are summarized in Algorithm 1." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 310, + 656, + 545, + 681 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 656, + 545, + 681 + ], + "spans": [ + { + "bbox": [ + 310, + 656, + 545, + 681 + ], + "type": "interline_equation", + "content": "\\mathcal {L} (\\text {i n p u t}, \\mathrm {w}) = \\mathcal {L} _ {0} (\\text {i n p u t}, \\mathrm {w}) + \\lambda \\gamma \\sum_ {i} \\| \\mathcal {C} \\left(\\mathrm {w} _ {b} ^ {i}\\right) - \\mathrm {w} _ {b} ^ {i} \\| ^ {2}, \\tag {7}", + "image_path": "34e45aedb7a985c4439bb01fe47bc1f575ac2ec47ba5721ac3033d99ecb91fdc.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 689, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 547, + 715 + ], + "type": "text", + "content": "It is noticeable that we use pre-trained BNN models for the learning process to avoid diverging during distance op" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 758 + ], + "type": "text", + "content": "6095" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "code", + "bbox": [ + 48, + 86, + 287, + 258 + ], + "blocks": [ + { + "bbox": [ + 48, + 72, + 286, + 84 + ], + "lines": [ + { + "bbox": [ + 48, + 72, + 286, + 84 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 286, + 84 + ], + "type": "text", + "content": "Algorithm 1 Forward propagation for the training process." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "code_caption" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "lines": [ + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "spans": [ + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": "Require: Input data, pre-train full-precision weight (w), threshold " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "(\\theta)" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " learning rate " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "(\\eta)" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " MST scaling factor " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "(\\lambda)" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " \n1: Load pre-train weight (w) \n2: for epoch " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "= 1\\rightarrow E" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " do \n3: " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{mst} = 0" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " \n4: for " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "l = 1" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " to L do \n5: " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "\\mathrm{w}_b^l = \\mathrm{Sign}(\\mathrm{w}_l)" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " [33] \n6: " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "\\mathrm{a}_b^{l - 1} = \\mathrm{Sign}(\\mathrm{a}_{l - 1})" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " \n7: for i = 1 to Cout do \n8: Update centers for " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "\\mathrm{w}_b^l" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " . \n9: " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "\\mathcal{C}(\\mathrm{w}_b^{li}) = \\underset {x}{\\operatorname{argmin}}(\\sum_{i = 1}^{C_{in}\\times M\\times M}\\| x - \\mathrm{w}_b^{li}\\|);x\\in \\mathbb{C}_l" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " \n10: " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{MST} = \\mathcal{L}_{MST} + \\sum \\| \\mathcal{C}(\\mathrm{w}_b^{li}) - \\mathrm{w}_b^{li}\\| ^2" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " \n11: end for \n12: " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "\\mathrm{a_l} = (\\mathrm{w_b^l*}\\mathrm{a_b^{l - 1}})\\odot \\alpha_l" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " \n13: end for \n14: Compute total loss: " + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "inline_equation", + "content": "\\mathcal{L} = \\mathcal{L}_0 + \\lambda *\\gamma *\\mathcal{L}_{MST}" + }, + { + "bbox": [ + 48, + 86, + 287, + 258 + ], + "type": "text", + "content": " \n15: end for" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "code_body" + } + ], + "index": 1, + "sub_type": "algorithm" + }, + { + "bbox": [ + 46, + 280, + 287, + 304 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 280, + 287, + 304 + ], + "spans": [ + { + "bbox": [ + 46, + 280, + 287, + 304 + ], + "type": "text", + "content": "timization time. In this paper, results from ReCu [33] are used and considered the baseline for comparison." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 312, + 180, + 324 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 312, + 180, + 324 + ], + "spans": [ + { + "bbox": [ + 47, + 312, + 180, + 324 + ], + "type": "text", + "content": "4.3. Streaming Acceleration" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 331, + 287, + 413 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 331, + 287, + 413 + ], + "spans": [ + { + "bbox": [ + 46, + 331, + 287, + 413 + ], + "type": "text", + "content": "Inspired by the streaming architecture in [31], this paper proposes an entire BNN high-speed architecture for BNN models applying our compression method. Specifically, the hardware architecture of a binary convolution layer is shown in Figure 6, in which the process is divided into two steps: 1) loading the input feature map to a line buffer and 2) executing XNOR + Popcount operation." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "spans": [ + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": "Loading input. Given a binary convolution layer with " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "M = 3" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": ", padding size " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "= 1" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": ", firstly, " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "C_{in}" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": " input feature maps are gradually loaded into " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "C_{in}" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": " line buffers with the size " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "2 \\times W_{in} + 3" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": ". When " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "W_{in} + 2" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": " registers in each line buffer are filled, " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "C_{in} \\times 3 \\times 3" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": " input pixels are selected from the line buffers for the convolution (XNOR + Popcount) operation. In standard calculation approach, the number of XNOR operations used for a binary convolution is " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "C_{out} \\times C_{in} \\times M \\times M" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": ". These operations can be separated into " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "C_{out}" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": " sub-operations corresponding to " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "C_{out}" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": " output channels; each sub-operation includes " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "C_{in} \\times M \\times M" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": " XNOR bit-operations and requires " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "C_{in} \\times M \\times M" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": " corresponding input pixels and weight values. In this proposed architecture, the difference is that the number of inputs for a particular sub-operation is lower than " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "C_{in} \\times M \\times M" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": " and equal to the distance between the corresponding vertex and parent vertex as in the constructed graph, except the sub-operation for the root vertex requiring full calculation with " + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "inline_equation", + "content": "C_{in} \\times M \\times M" + }, + { + "bbox": [ + 46, + 415, + 288, + 629 + ], + "type": "text", + "content": " XNORs." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "type": "text", + "content": "Perform convolution. This step executes the convolution operation with the order of calculation following the MST. As shown in Figure 6, the output of a specific PE (red arrow) is reused for the next PE to reduce computational cost. The PE for the output channel " + }, + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "type": "inline_equation", + "content": "i^{th}" + }, + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "type": "text", + "content": " needs " + }, + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "type": "inline_equation", + "content": "d_{ij}" + }, + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "type": "text", + "content": " weight values and executes " + }, + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "type": "inline_equation", + "content": "d_{ij}" + }, + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "type": "text", + "content": " XNOR operations with the corresponding Popcount operation, where " + }, + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "type": "text", + "content": " is the parent" + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 309, + 72, + 545, + 223 + ], + "blocks": [ + { + "bbox": [ + 309, + 72, + 545, + 223 + ], + "lines": [ + { + "bbox": [ + 309, + 72, + 545, + 223 + ], + "spans": [ + { + "bbox": [ + 309, + 72, + 545, + 223 + ], + "type": "image", + "image_path": "24fc45c146751253c6dc920dec9d9f014fee081123fc86c2039f5eeb0e738390.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 235, + 546, + 280 + ], + "lines": [ + { + "bbox": [ + 304, + 235, + 546, + 280 + ], + "spans": [ + { + "bbox": [ + 304, + 235, + 546, + 280 + ], + "type": "text", + "content": "Figure 6. High-speed hardware accelerator for a binary convolution layer, where the XNORs are simplified with NOT or simple straight connection, while computation on each PE corresponding to each output channel is executed gradually with the MST." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 292, + 546, + 400 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 292, + 546, + 400 + ], + "spans": [ + { + "bbox": [ + 304, + 292, + 546, + 400 + ], + "type": "text", + "content": "vertex of the vertex " + }, + { + "bbox": [ + 304, + 292, + 546, + 400 + ], + "type": "inline_equation", + "content": "i^{th}" + }, + { + "bbox": [ + 304, + 292, + 546, + 400 + ], + "type": "text", + "content": ". Besides, to eliminate memory for convolution weight storage, XNOR operations are simplified to NOT gate or straight connection. In terms of timing violations, we pipeline the Popcount operation by adding register lines among the adder tree to reduce computation complexity in a clock cycle. The exact number of register lines depends on the MST depth, frequency and hardware platform. Thus, depending on practical implementations, we adjust this number to meet the timing requirements." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 412, + 387, + 426 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 412, + 387, + 426 + ], + "spans": [ + { + "bbox": [ + 306, + 412, + 387, + 426 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 434, + 545, + 506 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 434, + 545, + 506 + ], + "spans": [ + { + "bbox": [ + 304, + 434, + 545, + 506 + ], + "type": "text", + "content": "In this section, we conduct experiments including software and hardware implementation to show the effectiveness of the proposed method for BNN compression. Training experiments are executed with the popular datasets CIFAR-10 and ImageNet via Pytorch, while hardware implementation is performed on the Xilinx FPGA platforms." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 515, + 516, + 528 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 515, + 516, + 528 + ], + "spans": [ + { + "bbox": [ + 306, + 515, + 516, + 528 + ], + "type": "text", + "content": "5.1. Learning and hardware implementation" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 534, + 546, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 534, + 546, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 534, + 546, + 712 + ], + "type": "text", + "content": "Training implementation: Because our proposed method is independent of other BNN accuracy optimization methods, in this paper, we select training results from the ReCU approach in [33] as a case study for further compressing. In doing so, VGG-small, ResNet-18/20 models are used to evaluate on CIFAR-10 dataset, while ResNet-18/34 are used for ImageNet. Regarding training in detail, we keep the configuration as in [33], except for the learning rate of 0.1. In addition, the " + }, + { + "bbox": [ + 304, + 534, + 546, + 712 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 534, + 546, + 712 + ], + "type": "text", + "content": " value is adjusted depending on the training models, datasets, and focused objectives. Meanwhile, the " + }, + { + "bbox": [ + 304, + 534, + 546, + 712 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 304, + 534, + 546, + 712 + ], + "type": "text", + "content": " parameter is scheduled following the learning rate. In this paper, when training with CIFAR-10, we select 1e-6 for ResNet-18, 5e-6 for ResNet-20, and 4e-6 for VGG-small. Meanwhile, for ImageNet, we select 1e-6 for ResNet-18 and 1e3 for ResNet-34." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6096" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 70, + 175, + 160 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 175, + 160 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 175, + 160 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 175, + 160 + ], + "type": "image", + "image_path": "ff6d24f46fdba1ec89158f7e31442b3bb87c5439ac9bb2efbffbb5383ce29bde.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 64, + 167, + 179, + 176 + ], + "lines": [ + { + "bbox": [ + 64, + 167, + 179, + 176 + ], + "spans": [ + { + "bbox": [ + 64, + 167, + 179, + 176 + ], + "type": "text", + "content": "a) MST distances of each layer (L)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 175, + 76, + 294, + 160 + ], + "blocks": [ + { + "bbox": [ + 175, + 76, + 294, + 160 + ], + "lines": [ + { + "bbox": [ + 175, + 76, + 294, + 160 + ], + "spans": [ + { + "bbox": [ + 175, + 76, + 294, + 160 + ], + "type": "image", + "image_path": "d96762b1efc4b4120336a51095a3cb0e1f929b9dd07665213e29cf4cbf3c9772.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 208, + 167, + 274, + 176 + ], + "lines": [ + { + "bbox": [ + 208, + 167, + 274, + 176 + ], + "spans": [ + { + "bbox": [ + 208, + 167, + 274, + 176 + ], + "type": "text", + "content": "b) Accuracy curves." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 181, + 286, + 214 + ], + "lines": [ + { + "bbox": [ + 46, + 181, + 286, + 214 + ], + "spans": [ + { + "bbox": [ + 46, + 181, + 286, + 214 + ], + "type": "text", + "content": "Figure 7. MST distance and top-1 % accuracy during the training process, where the Binary VGG-small model and CIFAR-10 dataset is used for the training experiment with 600 epochs." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 57, + 214, + 277, + 285 + ], + "blocks": [ + { + "bbox": [ + 57, + 214, + 277, + 285 + ], + "lines": [ + { + "bbox": [ + 57, + 214, + 277, + 285 + ], + "spans": [ + { + "bbox": [ + 57, + 214, + 277, + 285 + ], + "type": "table", + "html": "
λMST-depth#Params (Mbit)#Bit-Ops (GOps)Top-1 Acc. mean ± std (%)
1e-797.31.3910.21792.17 ± 0.07
5e-758.30.9980.18492.09 ± 0.06
1e-654.00.8640.16591.99 ± 0.07
5e-644.00.5320.11591.14 ± 0.08
1e-542.30.4220.09890.17 ± 0.14
", + "image_path": "192b7d0c0f5edbb73ff410d5ab7790f4667cefcfafd7627d4ba15ac8a3d22447.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 293, + 286, + 315 + ], + "lines": [ + { + "bbox": [ + 46, + 293, + 286, + 315 + ], + "spans": [ + { + "bbox": [ + 46, + 293, + 286, + 315 + ], + "type": "text", + "content": "Table 2. MST depth, number of parameters, bit-Ops, and accuracy w.r.t. different values of " + }, + { + "bbox": [ + 46, + 293, + 286, + 315 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 293, + 286, + 315 + ], + "type": "text", + "content": " on CIFAR-10 VGG-small model." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 326, + 286, + 397 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 326, + 286, + 397 + ], + "spans": [ + { + "bbox": [ + 46, + 326, + 286, + 397 + ], + "type": "text", + "content": "Hardware implementation: The inference hardware architecture is implemented on a Xilinx FPGA platform called xczu3eg-sbva484 part. Before programming to FPGA, the design is run with the corresponding C/C++ model and simulated via Synopsys VCS. Finally, Vivado 2018.3 is used for the design synthesis and implementation." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 406, + 147, + 418 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 406, + 147, + 418 + ], + "spans": [ + { + "bbox": [ + 47, + 406, + 147, + 418 + ], + "type": "text", + "content": "5.2. Ablation Studies" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 425, + 286, + 449 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 425, + 286, + 449 + ], + "spans": [ + { + "bbox": [ + 46, + 425, + 286, + 449 + ], + "type": "text", + "content": "In this section, experimental results and discussion related to hyper-parameter " + }, + { + "bbox": [ + 46, + 425, + 286, + 449 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 425, + 286, + 449 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 425, + 286, + 449 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 46, + 425, + 286, + 449 + ], + "type": "text", + "content": " are described." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "spans": [ + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "type": "text", + "content": "Effect of hyper-parameter " + }, + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "type": "text", + "content": ": As explained in Sec. 4.1, an additional loss related to MST distance is added for the learning. The effect of the loss depends on the " + }, + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "type": "text", + "content": ", while the " + }, + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "type": "text", + "content": " changes following the epoch. To facilitate the evaluation, Figure 7 provides MST distance curves for all binary convolution layers and training-validation accuracy curves in the entire learning process. In the first half-time, the " + }, + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "type": "text", + "content": " is still significant, and the training focuses on MST distance optimization, while the accuracy optimization is temporarily less affected. Consequently, the MST distance of all binary convolutions is significantly down, especially for the deeper layers with more channels, while the training accuracy suddenly decreases and the validation accuracy goes down and strongly fluctuates at this time. In the second half-time, the training focuses on accuracy optimization with the lower " + }, + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 46, + 449, + 286, + 700 + ], + "type": "text", + "content": " value. Thus, the training accuracy tends to increase, while the validation accuracy rises, too, with a lower fluctuation. Although the MST distance also escalates again on all layers, these values are lower than at the initial time, especially on deeper layers. This is the reason why we can save computational costs by using this approach." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 59, + 701, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 701, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 59, + 701, + 286, + 713 + ], + "type": "text", + "content": "Effect of hyper-parameter " + }, + { + "bbox": [ + 59, + 701, + 286, + 713 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 59, + 701, + 286, + 713 + ], + "type": "text", + "content": ": The hyper-parameter " + }, + { + "bbox": [ + 59, + 701, + 286, + 713 + ], + "type": "inline_equation", + "content": "\\lambda" + } + ] + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 335, + 69, + 521, + 228 + ], + "blocks": [ + { + "bbox": [ + 335, + 69, + 521, + 228 + ], + "lines": [ + { + "bbox": [ + 335, + 69, + 521, + 228 + ], + "spans": [ + { + "bbox": [ + 335, + 69, + 521, + 228 + ], + "type": "image", + "image_path": "c8a4a7b419849b5c80518ae23408d7bd904294f01ab40ac5c33c96e40815e45f.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 239, + 545, + 262 + ], + "lines": [ + { + "bbox": [ + 305, + 239, + 545, + 262 + ], + "spans": [ + { + "bbox": [ + 305, + 239, + 545, + 262 + ], + "type": "text", + "content": "Figure 8. Number of parameters and MST depth on each convolution layer w.r.t. different " + }, + { + "bbox": [ + 305, + 239, + 545, + 262 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 305, + 239, + 545, + 262 + ], + "type": "text", + "content": " values." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "spans": [ + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "text", + "content": "helps scale down the effect of the total MST distance to the new loss function. Each model has a different number of layers and channels that directly affects the total MST distance. Therefore, depending on the model, we adjust this hyper-parameter to balance the loss for accuracy and MST distance. In this section, the VGG-small model and CIFAR-10 dataset are used to estimate how the " + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "text", + "content": " impacts the number of parameters, bit-operations, MST-depth, and accuracy with the range of " + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "text", + "content": " from 1e-7 to 1e-5. Table 2 and Figure 8 provide the number of parameters, bit-operations, MST-depth, accuracy, and the number parameters for each binary convolution layer w.r.t different " + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "text", + "content": " values. Accordingly, the number of parameters, bit-operations, and accuracy tend to be lower with higher " + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "text", + "content": " values. However, the number of parameters/bit-ops is considerably reduced at " + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "inline_equation", + "content": "3.3\\times" + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "text", + "content": ", while the accuracy degradation is acceptable with " + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "inline_equation", + "content": "2\\%" + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "text", + "content": " when increasing the " + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "text", + "content": " from 1e-7 to 1e-5. Besides, the MST depth also decreases when the " + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "text", + "content": " value increases. Especially, when increasing " + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "text", + "content": " from 1e-7 to 5e-7, the depth reduces " + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "inline_equation", + "content": "1.67\\times" + }, + { + "bbox": [ + 304, + 281, + 545, + 508 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 515, + 484, + 528 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 515, + 484, + 528 + ], + "spans": [ + { + "bbox": [ + 306, + 515, + 484, + 528 + ], + "type": "text", + "content": "5.3. Comparison with SOTA methods" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 534, + 545, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 534, + 545, + 700 + ], + "spans": [ + { + "bbox": [ + 304, + 534, + 545, + 700 + ], + "type": "text", + "content": "To demonstrate the effectiveness of the proposed method, we perform a series of training experiments with various NN models on CIFAR-10, and ImageNet, then compare them with state-of-the-art methods. Specifically, for each NN model, we provide two experimental results corresponding to two cases 1) apply both the learning optimization in Sec. 4.2 and the MST reordering to the final training result (Ours 1); 2) directly apply the MST reordering to pretrained BNN models (Ours 2). In this paper, the pre-trained BNN models we use for fine-tuning and exploring the MST are provided by Xu et al. [33]. In terms of acceleration, a neural network model is fully trained on CIFAR-10 and implemented on an FPGA hardware platform to compare with recent hardware architectures." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 317, + 701, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 701, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 317, + 701, + 545, + 713 + ], + "type": "text", + "content": "Software training comparison: For CIFAR-10, we" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6097" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 49, + 70, + 285, + 292 + ], + "blocks": [ + { + "bbox": [ + 49, + 70, + 285, + 292 + ], + "lines": [ + { + "bbox": [ + 49, + 70, + 285, + 292 + ], + "spans": [ + { + "bbox": [ + 49, + 70, + 285, + 292 + ], + "type": "table", + "html": "
N-workMethod#Params (Mbit)#Bit-Ops (GOps)Top-1 Acc. (%)
VGG smallRAD[8]4.5710.60390.0
IR-Net[24]4.5710.60390.4
RBNN[20]4.5710.60391.3
Adabin[28]4.5710.60392.3
ReCU[33]4.5710.60392.4
SNN[32]3.0470.19491.0
Ours 1|20.556|1.6110.122|0.23291.5|93.3*
ResNet 18RAD[8]10.990.54790.5
IR-Net[24]10.990.54791.5
RBNN[20]10.990.54792.2
ReCU[33]10.990.54792.8
Adabin[28]10.990.54793.1
SNN[33]7.3240.28991.0
Ours 1|20.814|4.2930.104|0.21691.6|93.2*
ResNet 20DSQ[11]0.2670.04084.1
IR-Net[24]0.2670.04086.5
RBNN[20]0.2670.04086.5
ReCU[33]0.2670.04087.4
Adabin[28]0.2670.04088.2
SNN[32]0.1780.04085.1
Ours 1|20.096|0.1160.015|0.01786.5|88.0*
", + "image_path": "b91144cd9f211e09b0293548d89a1a5e548afdc859dba744472f19d50a6f283e.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 49, + 294, + 276, + 304 + ], + "lines": [ + { + "bbox": [ + 49, + 294, + 276, + 304 + ], + "spans": [ + { + "bbox": [ + 49, + 294, + 276, + 304 + ], + "type": "text", + "content": "* Accuracy after fine-tuning is at https://github.com/z-hXu/ReCU [33]." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "spans": [ + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": "conduct experiments on three neural BNN models: RestNet-18/20 and VGG-small. we compare our results with RAD [8], IR-Net [24], Adabin [28], ReCU [33], DSQ [11], and SNN [32]. Specifically, as shown in Table 3, when comparing Ours 1 with the highest-accuracy methods on all models, our proposed method reduces " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "8.2 \\times" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " parameters and " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "4.9 \\times" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " bit-Ops with a " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "0.97\\%" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " accuracy drop on VGG-small. Meanwhile, when directly exploring the MST on the pre-trained models, Ours 2 gets " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "2.8 \\times" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " parameters and " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "2.6 \\times" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " bit-Ops reduction without accuracy degradation. On ResNet-18, Ours 1 gives " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "13.50 \\times" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " parameters, " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "5.26 \\times" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " bit-Ops reduction with a " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "1.29\\%" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " accuracy drop, while Ours 2 reduces " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "2.6 \\times" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " parameters and " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "2.5 \\times" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " bit-Ops without compromising accuracy. Additionally, we have " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "2.78 \\times" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " parameters, " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "2.67 \\times" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " bit-Ops reduction, and a " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "1\\%" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " accuracy drop with Ours 1; " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "2.3 \\times" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " parameters, " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "2.35 \\times" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " bit-Ops reduction and " + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "inline_equation", + "content": "0\\%" + }, + { + "bbox": [ + 48, + 354, + 287, + 557 + ], + "type": "text", + "content": " accuracy drop on ResNet-20." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "spans": [ + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "text", + "content": "Compared Ours 1 with the compression method SNN [32] on all models, the proposed method obtains a better compression ratio with a maximum reduction of " + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "inline_equation", + "content": "9.0 \\times" + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "text", + "content": " parameters, " + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "inline_equation", + "content": "2.78 \\times" + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "text", + "content": " bit-Ops on ResNet-18 while yielding higher accuracy and up to maximum " + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "inline_equation", + "content": "1.4\\%" + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "text", + "content": " on ResNet-20. Meanwhile, with Our 2, we reduce maximum " + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "inline_equation", + "content": "1.89 \\times" + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "text", + "content": " parameters on VGG-small, " + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "inline_equation", + "content": "2.35 \\times" + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "text", + "content": " bit-Ops on ResNet-20, while achieving higher accuracy up to maximum " + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "inline_equation", + "content": "2.9\\%" + }, + { + "bbox": [ + 48, + 558, + 286, + 664 + ], + "type": "text", + "content": " on ResNet-20." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 666, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 666, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 49, + 666, + 286, + 712 + ], + "type": "text", + "content": "For ImageNet, experiments are implemented on ResNet18/34 and comparison is performed with BNN+ [16], BiReal [23], XNOR++ [4], IR-Net [24], Adabin [28], ReCU [33], SNN [32]. According to Table 4, Ours 1 reduces " + }, + { + "bbox": [ + 49, + 666, + 286, + 712 + ], + "type": "inline_equation", + "content": "3.2 \\times" + } + ] + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 309, + 70, + 543, + 224 + ], + "blocks": [ + { + "bbox": [ + 49, + 312, + 286, + 333 + ], + "lines": [ + { + "bbox": [ + 49, + 312, + 286, + 333 + ], + "spans": [ + { + "bbox": [ + 49, + 312, + 286, + 333 + ], + "type": "text", + "content": "Table 3. Comparison with the state-of-the-art methods on CIFAR-10. The bit-width is 1 for both activation and weight." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 309, + 70, + 543, + 224 + ], + "lines": [ + { + "bbox": [ + 309, + 70, + 543, + 224 + ], + "spans": [ + { + "bbox": [ + 309, + 70, + 543, + 224 + ], + "type": "table", + "html": "
N-workMethod#Params (Mbit)#Bit-Ops (GOps)Top-1 Acc. (%)
ResNet 18BNN+[16]10.991.67753.0
Bi-Real[23]10.991.67756.4
XNOR++[4]10.991.67757.1
IR-Net[24]10.991.67758.1
Adabin[28]10.991.67763.1
ReCU[33]10.991.67761.0
SNN[32]7.320.88356.3
Ours 1|23.43|4.840.636|0.71657.0|61.2*
ResNet 34Bi-Real[23]21.093.52662.2
IR-Net[24]21.093.52662.9
Adabin[28]21.093.52666.4
ReCU[33]21.093.52665.1
SNN[32]14.061.69661.4
Ours 1|29.44|9.511.550|1.55862.9|65.4*
", + "image_path": "8a2da48c78b5cea24be55378354969824779829817fd69abe402c0a5e2d32b67.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 309, + 227, + 535, + 237 + ], + "lines": [ + { + "bbox": [ + 309, + 227, + 535, + 237 + ], + "spans": [ + { + "bbox": [ + 309, + 227, + 535, + 237 + ], + "type": "text", + "content": "* Accuracy after fine-tuning is at https://github.com/z-hXu/ReCU [33]." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 6 + }, + { + "bbox": [ + 308, + 245, + 544, + 266 + ], + "lines": [ + { + "bbox": [ + 308, + 245, + 544, + 266 + ], + "spans": [ + { + "bbox": [ + 308, + 245, + 544, + 266 + ], + "type": "text", + "content": "Table 4. Comparison with the state-of-the-art methods on ImageNet. The bit-width is 1 for both activation and weight." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "spans": [ + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": "parameters, " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "2.6 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " bit-Ops on ResNet-18; and " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "2.23 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " parameters, " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "2.27 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " bit-Ops on ResNet-34, compared to the baseline [33], while the accuracy degradation is " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "4\\%" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "2.2\\%" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " on ResNet18 and ResNet-34, respectively. Ours 2 achieves " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "2.27 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " parameters, " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "2.34 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " bit-Ops reduction on ResNet-18; and " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "2.2 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " parameters, " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "2.26 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " bit-Ops reduction without accuracy drop. Compared to SNN with the highest compression ratio recently, our proposed method with Ours 1 saves " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "2.13 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " parameters and " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "1.3 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " bit-Ops on ResNet-18, " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "1.49 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " parameters and " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "1.09 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " bit-Ops on ResNet-34, while the trained models give higher accuracy of " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "0.7\\%" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "1.5\\%" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " on ResNet-18, ResNet-34, respectively. Meanwhile, Ours 2 without accuracy drop saves up to " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "1.51 / 1.47 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " parameters and " + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "inline_equation", + "content": "1.23 / 1.08 \\times" + }, + { + "bbox": [ + 308, + 287, + 544, + 454 + ], + "type": "text", + "content": " bit-Ops on ResNet-18/34, respectively." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 308, + 455, + 544, + 633 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 455, + 544, + 633 + ], + "spans": [ + { + "bbox": [ + 308, + 455, + 544, + 633 + ], + "type": "text", + "content": "Hardware implementation comparison: Table 5 provides the hardware performance comparison with previous works using CIFAR-10 for the training. We compare the proposed architecture with FINN [30], FINN-R [3] from Xilinx, ReBNet [10] and the design in [31]. Accordingly, the proposed accelerator takes the leading place in both speed and area efficiency (FPS/LUTs). More specifically, it performs " + }, + { + "bbox": [ + 308, + 455, + 544, + 633 + ], + "type": "inline_equation", + "content": "1.6 \\times" + }, + { + "bbox": [ + 308, + 455, + 544, + 633 + ], + "type": "text", + "content": " faster than the fastest previous work (FINN), while obtaining " + }, + { + "bbox": [ + 308, + 455, + 544, + 633 + ], + "type": "inline_equation", + "content": "3.7 \\times" + }, + { + "bbox": [ + 308, + 455, + 544, + 633 + ], + "type": "text", + "content": " area efficiency with a little higher accuracy. In addition, compared to [31], our method gains over " + }, + { + "bbox": [ + 308, + 455, + 544, + 633 + ], + "type": "inline_equation", + "content": "1.81 \\times" + }, + { + "bbox": [ + 308, + 455, + 544, + 633 + ], + "type": "text", + "content": " area efficiency. Besides, to compare our method with the K-mean approach, we implement another design from the same training result with the K-mean method. According to Table 5, our method performs better " + }, + { + "bbox": [ + 308, + 455, + 544, + 633 + ], + "type": "inline_equation", + "content": "1.25 \\times" + }, + { + "bbox": [ + 308, + 455, + 544, + 633 + ], + "type": "text", + "content": " in terms of resources and area efficiency." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 308, + 646, + 377, + 657 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 646, + 377, + 657 + ], + "spans": [ + { + "bbox": [ + 308, + 646, + 377, + 657 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 308, + 666, + 544, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 666, + 544, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 666, + 544, + 712 + ], + "type": "text", + "content": "In conclusion, this paper introduces a comprehensive method for compressing BNNs, which covers the entire process from learning to hardware implementation. By utilizing the minimum spanning tree (MST), we effectively re" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 750, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 750, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 750, + 314, + 757 + ], + "type": "text", + "content": "6098" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 59, + 70, + 276, + 177 + ], + "blocks": [ + { + "bbox": [ + 59, + 70, + 276, + 177 + ], + "lines": [ + { + "bbox": [ + 59, + 70, + 276, + 177 + ], + "spans": [ + { + "bbox": [ + 59, + 70, + 276, + 177 + ], + "type": "table", + "html": "
DesignFreq (MHz)LUTsAcc. (%)FPS (K)FPS/ LUTs
FINN[30]20046,25380.1220.47
FINN[30]125365,96380.11280.35
FINN-R[3]237332,63780.11050.31
FINN-R[3]30041,73380.1200.48
FINN[3]30025,43180.11.90.07
ReBNet[10]20053,20080.660.11
[31]210290,01280.22050.70
Ours (K-mean)210201,43480.52051.01
Ours (MST)210161,29480.52051.27
", + "image_path": "605662c57c26d4ba2a2731a211c3012b906f1d01143def223e2466bd63b9138d.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 185, + 287, + 207 + ], + "lines": [ + { + "bbox": [ + 47, + 185, + 287, + 207 + ], + "spans": [ + { + "bbox": [ + 47, + 185, + 287, + 207 + ], + "type": "text", + "content": "Table 5. Hardware performance comparison with the state-of-the-art architectures on CIFAR-10." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 219, + 287, + 304 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 219, + 287, + 304 + ], + "spans": [ + { + "bbox": [ + 46, + 219, + 287, + 304 + ], + "type": "text", + "content": "duce the computation cost of binary convolution calculation. To optimize the MST during the training stage, a learning algorithm is proposed. Moreover, we present a hardware implementation for the inference task. Our experimental results demonstrate that the proposed method significantly reduces computation costs while maintaining high accuracy, making it promising for practical applications." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 316, + 162, + 330 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 316, + 162, + 330 + ], + "spans": [ + { + "bbox": [ + 47, + 316, + 162, + 330 + ], + "type": "text", + "content": "7. Acknowledgements" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 335, + 287, + 443 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 335, + 287, + 443 + ], + "spans": [ + { + "bbox": [ + 46, + 335, + 287, + 443 + ], + "type": "text", + "content": "This work was supported by the NRF grant funded by the Korea government(MSIT) (No. RS-2023-00207816), and part by IITP Grant funded by MSIT (Artificial Intelligence Innovation Hub) under Grant 2021-0-02068, (No. RS-2022-00155911, AI Convergence Innovation Human Resources Development (Kyung Hee University)), IITP No.2019-0-01287, Evolvable Deep Learning Model Generation Platform for Edge Computing and ITRC support program (IITP-2023-RS-2023-00258649)." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 456, + 106, + 468 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 456, + 106, + 468 + ], + "spans": [ + { + "bbox": [ + 47, + 456, + 106, + 468 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 477, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 11, + "blocks": [ + { + "bbox": [ + 53, + 477, + 287, + 509 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 477, + 287, + 509 + ], + "spans": [ + { + "bbox": [ + 53, + 477, + 287, + 509 + ], + "type": "text", + "content": "[1] Richard Bellman. Dynamic programming treatment of the travelling salesman problem. Journal of the ACM (JACM), 9(1):61-63, 1962. 2, 5" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 511, + 287, + 554 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 511, + 287, + 554 + ], + "spans": [ + { + "bbox": [ + 53, + 511, + 287, + 554 + ], + "type": "text", + "content": "[2] Yoshua Bengio, Nicholas Léonard, and Aaron Courville. Estimating or propagating gradients through stochastic neurons for conditional computation. arXiv preprint arXiv:1308.3432, 2013. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 557, + 287, + 621 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 557, + 287, + 621 + ], + "spans": [ + { + "bbox": [ + 53, + 557, + 287, + 621 + ], + "type": "text", + "content": "[3] Michaela Blott, Thomas B Preußer, Nicholas J Fraser, Giulio Gambardella, Kenneth O'brien, Yaman Umuroglu, Miriam Leeser, and Kees Vissers. Finn-r: An end-to-end deep-learning framework for fast exploration of quantized neural networks. ACM Transactions on Reconfigurable Technology and Systems (TRETS), 11(3):1-23, 2018. 2, 8, 9" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 624, + 287, + 656 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 624, + 287, + 656 + ], + "spans": [ + { + "bbox": [ + 53, + 624, + 287, + 656 + ], + "type": "text", + "content": "[4] Adrian Bulat and Georgios Tzimiropoulos. Xnornet++: Improved binary neural networks. arXiv preprint arXiv:1909.13863, 2019. 1, 3, 8" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 658, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 658, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 53, + 658, + 287, + 712 + ], + "type": "text", + "content": "[5] Zhaowei Cai, Xiaodong He, Jian Sun, and Nuno Vasconcelos. Deep learning with low precision by half-wave gaussian quantization. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5918-5926, 2017. 2" + } + ] + } + ], + "index": 10 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 26, + "blocks": [ + { + "bbox": [ + 311, + 73, + 546, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 73, + 546, + 116 + ], + "spans": [ + { + "bbox": [ + 311, + 73, + 546, + 116 + ], + "type": "text", + "content": "[6] Yu-Hsin Chen, Tushar Krishna, Joel S Emer, and Vivienne Sze. Eyeriss: An energy-efficient reconfigurable accelerator for deep convolutional neural networks. IEEE journal of solid-state circuits, 52(1):127-138, 2016. 1" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 311, + 118, + 547, + 171 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 118, + 547, + 171 + ], + "spans": [ + { + "bbox": [ + 311, + 118, + 547, + 171 + ], + "type": "text", + "content": "[7] Matthieu Courbariaux, Itay Hubara, Daniel Soudry, Ran El-Yaniv, and Yoshua Bengio. Binarized neural networks: Training deep neural networks with weights and activations constrained to + 1 or -1. arXiv preprint arXiv:1602.02830, 2016. 1, 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 311, + 174, + 546, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 174, + 546, + 228 + ], + "spans": [ + { + "bbox": [ + 311, + 174, + 546, + 228 + ], + "type": "text", + "content": "[8] Ruizhou Ding, Ting-Wu Chin, Zeye Liu, and Diana Marculescu. Regularizing activation distribution for training binarized deep networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 11408-11417, 2019. 8" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 311, + 230, + 546, + 273 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 230, + 546, + 273 + ], + "spans": [ + { + "bbox": [ + 311, + 230, + 546, + 273 + ], + "type": "text", + "content": "[9] Cheng Fu, Shilin Zhu, Hao Su, Ching-En Lee, and Jishen Zhao. Towards fast and energy-efficient binarized neural network inference on fpga. arXiv preprint arXiv:1810.02068, 2018. 1, 2, 3, 4" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 275, + 545, + 329 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 275, + 545, + 329 + ], + "spans": [ + { + "bbox": [ + 307, + 275, + 545, + 329 + ], + "type": "text", + "content": "[10] Mohammad Ghasemzadeh, Mohammad Samragh, and Farinaz Koushanfar. Rebnet: Residual binarized neural network. In 2018 IEEE 26th annual international symposium on field-programmable custom computing machines (FCCM), pages 57-64. IEEE, 2018. 2, 8, 9" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 331, + 545, + 396 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 331, + 545, + 396 + ], + "spans": [ + { + "bbox": [ + 307, + 331, + 545, + 396 + ], + "type": "text", + "content": "[11] Ruihao Gong, Xianglong Liu, Shenghu Jiang, Tianxiang Li, Peng Hu, Jiazhen Lin, Fengwei Yu, and Junjie Yan. Differentiable soft quantization: Bridging full-precision and low-bit neural networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4852–4861, 2019. 8" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 398, + 545, + 441 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 398, + 545, + 441 + ], + "spans": [ + { + "bbox": [ + 307, + 398, + 545, + 441 + ], + "type": "text", + "content": "[12] Song Han, Huizi Mao, and William J Dally. Deep compression: Compressing deep neural networks with pruning, trained quantization and huffman coding. arXiv preprint arXiv:1510.00149, 2015. 1" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 443, + 545, + 485 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 443, + 545, + 485 + ], + "spans": [ + { + "bbox": [ + 307, + 443, + 545, + 485 + ], + "type": "text", + "content": "[13] John A Hartigan and Manchek A Wong. Algorithm as 136: A k-means clustering algorithm. Journal of the royal statistical society. series c (applied statistics), 28(1):100-108, 1979. 2, 4" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 488, + 545, + 532 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 488, + 545, + 532 + ], + "spans": [ + { + "bbox": [ + 307, + 488, + 545, + 532 + ], + "type": "text", + "content": "[14] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 1, 2, 5" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 533, + 545, + 566 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 533, + 545, + 566 + ], + "spans": [ + { + "bbox": [ + 307, + 533, + 545, + 566 + ], + "type": "text", + "content": "[15] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, et al. Distilling the knowledge in a neural network. arXiv preprint arXiv:1503.02531, 2(7), 2015. 1" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 567, + 545, + 609 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 567, + 545, + 609 + ], + "spans": [ + { + "bbox": [ + 307, + 567, + 545, + 609 + ], + "type": "text", + "content": "[16] Itay Hubara, Matthieu Courbariaux, Daniel Soudry, Ran El-Yaniv, and Yoshua Bengio. Binarized neural networks. Advances in neural information processing systems, 29, 2016. 8" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 613, + 545, + 666 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 613, + 545, + 666 + ], + "spans": [ + { + "bbox": [ + 307, + 613, + 545, + 666 + ], + "type": "text", + "content": "[17] Hyeonuk Kim, Jaehyeong Sim, Yeongjae Choi, and Lee-Sup Kim. A kernel decomposition architecture for binary-weight convolutional neural networks. In Proceedings of the 54th Annual Design Automation Conference 2017, pages 1-6, 2017. 1, 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 668, + 545, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 668, + 545, + 690 + ], + "spans": [ + { + "bbox": [ + 307, + 668, + 545, + 690 + ], + "type": "text", + "content": "[18] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images. 2009. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 692, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 692, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 692, + 545, + 713 + ], + "type": "text", + "content": "[19] Dongsoo Lee, Se Jung Kwon, Byeongwook Kim, Yongkwon Jeon, Baeseong Park, and Jeongin Yun. Flexor: Train" + } + ] + } + ], + "index": 25 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6099" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 714 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "type": "text", + "content": "able fractional quantization. Advances in neural information processing systems, 33:1311-1321, 2020. 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 95, + 287, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 95, + 287, + 139 + ], + "spans": [ + { + "bbox": [ + 48, + 95, + 287, + 139 + ], + "type": "text", + "content": "[20] Mingbao Lin, Rongrong Ji, Zihan Xu, Baochang Zhang, Yan Wang, Yongjian Wu, Feiyue Huang, and Chia-Wen Lin. Rotated binary neural network. Advances in neural information processing systems, 33:7474-7485, 2020. 1, 3, 8" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 140, + 287, + 172 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 140, + 287, + 172 + ], + "spans": [ + { + "bbox": [ + 48, + 140, + 287, + 172 + ], + "type": "text", + "content": "[21] Xiaofan Lin, Cong Zhao, and Wei Pan. Towards accurate binary convolutional neural network. Advances in neural information processing systems, 30, 2017. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 172, + 287, + 227 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 172, + 287, + 227 + ], + "spans": [ + { + "bbox": [ + 48, + 172, + 287, + 227 + ], + "type": "text", + "content": "[22] Zechun Liu, Zhiqiang Shen, Marios Savvides, and Kwang-Ting Cheng. Reactnet: Towards precise binary neural network with generalized activation functions. In European conference on computer vision, pages 143-159. Springer, 2020. 1, 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 228, + 287, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 228, + 287, + 293 + ], + "spans": [ + { + "bbox": [ + 48, + 228, + 287, + 293 + ], + "type": "text", + "content": "[23] Zechun Liu, Baoyuan Wu, Wenhan Luo, Xin Yang, Wei Liu, and Kwang-Ting Cheng. Bi-real net: Enhancing the performance of 1-bit cnns with improved representational capability and advanced training algorithm. In Proceedings of the European conference on computer vision (ECCV), pages 722-737, 2018. 1, 3, 8" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 293, + 287, + 358 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 293, + 287, + 358 + ], + "spans": [ + { + "bbox": [ + 48, + 293, + 287, + 358 + ], + "type": "text", + "content": "[24] Haotong Qin, Ruihao Gong, Xianglong Liu, Mingzhu Shen, Ziran Wei, Fengwei Yu, and Jingkuan Song. Forward and backward information retention for accurate binary neural networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2250-2259, 2020. 3, 8" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 360, + 287, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 360, + 287, + 403 + ], + "spans": [ + { + "bbox": [ + 48, + 360, + 287, + 403 + ], + "type": "text", + "content": "[25] Mohammad Rastegari, Vicente Ordonez, Joseph Redmon, and Ali Farhadi. Xnor-net: Imagenet classification using binary convolutional neural networks. In European conference on computer vision, pages 525-542. Springer, 2016. 1, 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 404, + 287, + 459 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 404, + 287, + 459 + ], + "spans": [ + { + "bbox": [ + 48, + 404, + 287, + 459 + ], + "type": "text", + "content": "[26] Olga Russakovsky, Jia Deng, Hao Su, Jonathan Krause, Sanjeev Satheesh, Sean Ma, Zhiheng Huang, Andrej Karpathy, Aditya Khosla, Michael Bernstein, et al. Imagenet large scale visual recognition challenge. International journal of computer vision, 115(3):211-252, 2015. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 459, + 287, + 514 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 459, + 287, + 514 + ], + "spans": [ + { + "bbox": [ + 48, + 459, + 287, + 514 + ], + "type": "text", + "content": "[27] Mark Sandler, Andrew Howard, Menglong Zhu, Andrey Zh-moginov, and Liang-Chieh Chen. Mobilenetv2: Inverted residuals and linear bottlenecks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4510-4520, 2018. 1" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 514, + 287, + 558 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 514, + 287, + 558 + ], + "spans": [ + { + "bbox": [ + 48, + 514, + 287, + 558 + ], + "type": "text", + "content": "[28] Zhijun Tu, Xinghao Chen, Pengju Ren, and Yunhe Wang. Adabin: Improving binary neural networks with adaptive binary sets. In European Conference on Computer Vision, pages 379-395. Springer, 2022. 3, 8" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 559, + 287, + 581 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 559, + 287, + 581 + ], + "spans": [ + { + "bbox": [ + 48, + 559, + 287, + 581 + ], + "type": "text", + "content": "[29] William Thomas Tutte and William Thomas Tutte. Graph theory, volume 21. Cambridge university press, 2001. 4" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 581, + 287, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 581, + 287, + 646 + ], + "spans": [ + { + "bbox": [ + 48, + 581, + 287, + 646 + ], + "type": "text", + "content": "[30] Yaman Umuroglu, Nicholas J Fraser, Giulio Gambardella, Michaela Blott, Philip Leong, Magnus Jahre, and Kees Vissers. Finn: A framework for fast, scalable binarized neural network inference. In Proceedings of the 2017 ACM/SIGDA international symposium on field-programmable gate arrays, pages 65-74, 2017. 1, 2, 8, 9" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 647, + 287, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 287, + 690 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 287, + 690 + ], + "type": "text", + "content": "[31] Quang Hieu Vo, Ngoc Linh Le, Faaiz Asim, Lok-Won Kim, and Choong Seon Hong. A deep learning accelerator based on a streaming architecture for binary neural networks. IEEE Access, 10:21141-21159, 2022. 1, 2, 3, 4, 5, 6, 8, 9" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "type": "text", + "content": "[32] Yikai Wang, Yi Yang, Fuchun Sun, and Anbang Yao. Sub-bit neural networks: Learning to compress and accelerate binary" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 151 + ], + "type": "list", + "angle": 0, + "index": 17, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "text", + "content": "neural networks. In International Conference on Computer Vision (ICCV), 2021. 1, 2, 3, 8" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 95, + 545, + 151 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 95, + 545, + 151 + ], + "spans": [ + { + "bbox": [ + 307, + 95, + 545, + 151 + ], + "type": "text", + "content": "[33] Zihan Xu, Mingbao Lin, Jianzhuang Liu, Jie Chen, Ling Shao, Yue Gao, Yonghong Tian, and Rongrong Ji. Recu: Reviving the dead weights in binary neural networks. In Proceedings of the IEEE/CVF international conference on computer vision, pages 5198-5208, 2021. 1, 2, 3, 5, 6, 7, 8" + } + ] + } + ], + "index": 16 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "6100" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MULLER_ Multilayer Laplacian Resizer for Vision/540b48e0-0e9c-4eba-a984-866547201e9c_content_list.json b/2023/MULLER_ Multilayer Laplacian Resizer for Vision/540b48e0-0e9c-4eba-a984-866547201e9c_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..fe1d234583bd48657577adff075e1228f932439b --- /dev/null +++ b/2023/MULLER_ Multilayer Laplacian Resizer for Vision/540b48e0-0e9c-4eba-a984-866547201e9c_content_list.json @@ -0,0 +1,1454 @@ +[ + { + "type": "text", + "text": "MULLER: Multilayer Laplacian Resizer for Vision", + "text_level": 1, + "bbox": [ + 225, + 130, + 743, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Zhengzhong Tu, Peyman Milanfar, Hossein Talebi \nGoogle Research", + "bbox": [ + 285, + 180, + 684, + 215 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "zhengzhongtu@gmail.com", + "bbox": [ + 380, + 219, + 589, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 268, + 313, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Image resizing operation is a fundamental preprocessing module in modern computer vision. Throughout the deep learning revolution, researchers have overlooked the potential of alternative resizing methods beyond the commonly used resize that are readily available, such as nearest-neighbors, bilinear, and bicubic. The key question of our interest is whether the front-end resize affects the performance of deep vision models? In this paper, we present an extremely lightweight multilayer Laplacian resolver with only a handful of trainable parameters, dubbed MULLER resolver. MULLER has a bandpass nature in that it learns to boost details in certain frequency subbands that benefit the downstream recognition models. We show that MULLER can be easily plugged into various training pipelines, and it effectively boosts the performance of the underlying vision task with little to no extra cost. Specifically, we select a state-of-the-art vision Transformer, MaxViT [50], as the baseline, and show that, if trained with MULLER, MaxViT gains up to $0.6\\%$ top-1 accuracy, and meanwhile enjoys $36\\%$ inference cost saving to achieve similar top-1 accuracy on ImageNet-1k, as compared to the standard training scheme. Notably, MULLER's performance also scales with model size and training data size such as ImageNet-21k and JFT, and it is widely applicable to multiple vision tasks, including image classification, object detection and segmentation, as well as image quality assessment. The code is available at https://github.com/google-research/google-research/tree/master/muller.", + "bbox": [ + 76, + 301, + 473, + 739 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 768, + 209, + 784 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Most computer vision problems such as image classification, object detection, video recognition, and image/video generation have seen groundbreaking advancement by deep neural networks-based models that are trained on web-scale, human-curated datasets [11, 12, 15, 15, 24, 33, 35, 40, 41, 46, 53, 58]. In any of the underlining training infrastructures like Tensorflow [1] and PyTorch [30], image resizing", + "bbox": [ + 75, + 794, + 468, + 902 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/3e7a77c8b92bb54410178bb3d56bf75d6fbe88989d82a86de0b20bd59a5fdb9b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 514, + 268, + 879, + 406 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/48a77002fff2f276b713f09dc160eb47a9ea71ad26b521b6e741d167fcf0729d.jpg", + "image_caption": [ + "Figure 1. Top: our proposed learned resizer can push forward a strong vision Transformer MaxViT [50] by up to $0.6\\%$ top-1 accuracy on ImageNet-1K with no extra inference cost. Results for other backbones are shown in Sec. 4.2. Bottom: demonstration of the learned resizer - with detail-boosted input image, the classification accuracy of the exemplar image has improved." + ], + "image_footnote": [], + "bbox": [ + 511, + 411, + 883, + 523 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "is an essential preprocessing step which enables efficient gradient-based training of networks with millions of trainable parameters. Moreover, the factor of image size can sometimes significantly impact the performance of various tasks, particularly those requiring high-resolution prediction. Although neural architectures have been revolutionized by CNNs and Transformers, surprisingly limited attention has been paid to the role of image resizing operations.", + "bbox": [ + 496, + 671, + 893, + 792 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Resizing or rescaling refers to the process of changing the resolution of an image, while largely preserving its content for human or machine perception. There are several major reasons for using resizing: (1) The mini-batch gradient-based training scheme requires the same image resolution in a batch, (2) Resizing can help to reduce computational complexity, making it easier and faster to train", + "bbox": [ + 496, + 795, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "6877", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "and inference neural networks, (3) Smaller images consume lower memory footprint, enabling stable training of large models like Transformers with larger batch-size, (4) Resizing contributes to improving model generalization and robustness by reducing overfitting to specific image size and scales, making the models more flexible and applicable to real-world scenarios.", + "bbox": [ + 75, + 90, + 470, + 196 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Moreover, resizing is an integral component of remote inference frameworks. Typically, to maintain the bandwidth efficiency of the communication network, before sending an image to the inference server, a thumbnail generator downscales the image to a fixed resolution (e.g. 480p). The thumbnail generator can be located on the client side (e.g. smart phone), or it can be part of a cloud storage system. This means that in most cases the inference server does not have access to the original image.", + "bbox": [ + 75, + 199, + 468, + 335 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Basic resizing functions such as nearest-neighbor or bilinear interpolation have long been the go-to options with little to no deliberate consideration in most training software. While these simple methods offer greater simplicity and efficiency, they are not optimized for specific computer vision tasks and may lead to the loss of important visual features or details, which can, sometimes, result in significant performance degradation [29, 45]. To overcome this limitation, researchers have proposed learned resizers (or downsamplers) [3, 45] that leverage the deep neural networks to learn image resizing directly from data, yielding improved performance on several tasks. However, one of the main challenges with these learned resizers is that they often require a large number of parameters, and high computational overhead during training and inference. Note that this is specifically a bottleneck in remote inference where the resize (a.k.a thumbnail generator) is not in the inference server, and may have limited computational resources to run a heavy neural net resolver. Additionally, less-bounded resizers can sometimes be difficult to transfer to new tasks or datasets due to their excessive model capability.", + "bbox": [ + 75, + 339, + 470, + 656 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this paper, we introduce an incredibly lightweight learned resizer, which we call MULLER, that operates on multilayer Laplacian decomposition of images (see Fig. 2). Our method requires very few parameters and FLOPs, and does not incur any extra training cost, outperforming existing methods in terms of computational efficiency, parameter efficiency, and transferability. We show that it is the ability-to-learn that makes a better resizer, but not the capacity of the resizer - our MULLER resizer only learns four parameters and is more effective than previous complex ones using deep residual blocks [45]. We also demonstrate that our method can be used as a drop-in replacement for off-the-shelf resizing functions on several vision tasks, including classification, object detection and segmentation, and image quality assessment, resulting in significant performance improvements without any extra cost. As shown in Fig. 1,", + "bbox": [ + 75, + 659, + 470, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "for example, training with the MULLER responder achieves up to $0.6\\%$ performance gain, using a state-of-the-art backbone MaxViT [50] as the testbed. Our contributions are:", + "bbox": [ + 496, + 90, + 890, + 137 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose a surprisingly simple and lightweight resolver, that can be used as a drop-in replacement for off-the-shelf resizing functions like bilinear resizing.", + "- We demonstrate its applications to multiple computer vision tasks, including image classification, object detection and segmentation, and image quality assessment, showing superior performance over existing approaches.", + "- Extensive ablation studies, analysis, and visualization results are provided to show the robustness and generalization of the proposed resizer for various model scales, benchmarks, and tasks." + ], + "bbox": [ + 500, + 146, + 890, + 321 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 345, + 640, + 363 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Resizing in vision. Resizing is a crucial preprocessing step to train deep learning vision models. Due to their simplicity, efficiency and availability, nearest-neighbor and bilinear interpolations are the most widely used resizing methods in both training, inference, and serving. These simple approaches, however, can suffer from detail loss and artifacts, and the degraded image quality might hamper the performance of downstream visual recognition tasks, especially when the resizing factor is large.", + "bbox": [ + 496, + 372, + 890, + 507 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Some recent works have explored to use learning-based methods for image downscaling to enhance the desired content in the resized images from training data [3,4,20,32,45, 61]. For example, the authors of [3,4] proposed a residual CNN module for downscaling, and jointly trained it with an image compression network to generate \"compression-friendly\" representations. [45] introduced a CNN-based learned resizer for various computer vision tasks, including image classification and image quality assessment. Similarly, the idea of learned rescaling has been applied to other computer vision applications [20, 32, 57, 61], showing improved performance in detection and recognition.", + "bbox": [ + 496, + 508, + 890, + 688 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Image processing for machine vision. Image processing or enhancement problems such as super-resolution [19, 37], denoising [59], and deblurring [48, 49] have been longstanding challenges in computer vision. Recent works have focused on building larger-scale, diverse benchmarks, exploring novel model architectures, and improving training techniques. These works aim to produce visually pleasing outputs, often measured by conventional metrics like PSNR or SSIM [54], or through human evaluations, without considering downstream recognition performance of the output.", + "bbox": [ + 496, + 689, + 890, + 839 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "There exists a number of works relating image processing to image recognition performance, or machine-oriented image processing. Some works [17, 18, 34, 60] use image recognition accuracy as supplementary metrics besides", + "bbox": [ + 496, + 840, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "6878", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/90ccee828a535faba6416e26bc767b0ff615fb739efd224647c3cfd340377fd3.jpg", + "image_caption": [ + "Figure 2. The architecture of the proposed multilayer Laplacian resizer (MULLER). The resizer decomposes the input image into multiple layers of Laplacian residuals and then adds them back to the default resized image. The MULLER resizer is jointly trained with the downstream recognition model." + ], + "image_footnote": [], + "bbox": [ + 133, + 87, + 816, + 237 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "visual quality metrics to evaluate the performance of image restoration models. Towards recognition-aware training, [10] proposed to train super-resolution using object detection loss and show promising results over conventional methods. Other works [39, 42] introduce pre-editing networks before image compression to improve compression efficiency without sacrificing classification accuracy. Recently, Liu et al. [26] developed an approach to train the processing models under the objective of image recognition accuracy, and investigated the efficacy of popular preprocessing operations such as super-resolution, denoising, and JPEG-deblocking on improving recognition performance. More similar studies [16, 22, 23, 36] have been conducted to jointly train a processing model like denoising, dehazing, face reconstruction, together with recognition model to achieve better image processing for recognition quality.", + "bbox": [ + 75, + 311, + 472, + 554 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Proposed Approach", + "text_level": 1, + "bbox": [ + 76, + 569, + 267, + 585 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this section, we introduce our proposed multilayer Laplacian resizer (MULLER, overviewed in Fig. 2), and discuss how we employ it for training several popular vision tasks. Unlike previous proposed resizers [3, 45], we aim to keep the computational cost of the model as low as possible such that it can replace existing resizers (e.g., bilinear) without extra cost, but also there is a notable performance gain. Our proposed approach is different in that (1) it is orders of magnitude faster, hence more scalable (to large image size), (2) it only has a handful of parameters which allows for better generalization, (3) it adds almost no extra training cost to the system. We show that with learning merely a couple of parameters, training with an added resizing module performs as effective as having a heavy downscaling network with several thousand parameter counts.", + "bbox": [ + 75, + 595, + 468, + 821 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Resizer Model", + "text_level": 1, + "bbox": [ + 76, + 832, + 225, + 847 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Image resizing models can be generally formulated as:", + "bbox": [ + 96, + 856, + 457, + 872 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {y} = \\mathbf {F} _ {2} \\left(\\mathbf {R} \\left(\\mathbf {F} _ {1} (\\mathbf {x}); h ^ {\\prime}, w ^ {\\prime}\\right)\\right), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 176, + 883, + 468, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\mathbf{R}$ maps the input image $\\mathbf{x}$ of size $h\\times w$ to an output image of size $h^{\\prime}\\times w^{\\prime}$ by computing the pixel values at the target spatial locations. $\\mathbf{F}_1$ and $\\mathbf{F}_2$ denote optional pre- and post-filtering operations. Typically, $\\mathbf{F}_1$ and $\\mathbf{F}_2$ can be identity functions, and $\\mathbf{R}$ is chosen as a simple interpolation method like nearest-neighbor, bilinear, or bicubic. To learn more powerful resizing, learned resize has been proposed [3,4,45] by applying a base resizer on intermediate neural activations, wherein $\\mathbf{F}_1$ and $\\mathbf{F}_2$ are two designed CNNs applied at the original and output resolutions, respectively. Despite showing promising performance, however, these resize typically suffer from high computational complexity, and thus their net performance gain might be compromised in terms of the overall inference cost.", + "bbox": [ + 496, + 311, + 890, + 523 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Proposed MULLER Resizer", + "text_level": 1, + "bbox": [ + 498, + 530, + 754, + 546 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We are inspired by the observations that these different learned resize, if properly regularized, will often learn to enhance edges, details, or sharpness of the image to benefit downstream tasks [3, 4]. To this end, we present to date, the simplest learned resizing model, using multilayer Laplacian decomposition, that is able to achieve 'bandpassed' detail and texture manipulation with only a handful of learnable parameters. Fig. 2 shows the architecture of the proposed MULLER resize. MULLER has the following form:", + "bbox": [ + 496, + 553, + 890, + 690 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {z} = \\underbrace {\\mathbf {R} (\\mathbf {x})} _ {\\text {B a s e i m a g e}} + \\sum_ {\\ell = 1} ^ {k} \\underbrace {\\sigma \\left(\\alpha_ {\\ell} \\left(\\mathbf {R} \\left(\\left(\\mathbf {W} _ {\\ell} - \\mathbf {W} _ {\\ell + 1}\\right) \\mathbf {x}\\right) + \\beta_ {\\ell}\\right)\\right)} _ {\\text {E n h a n c e d d e t a i l s i n e a c h s u b b a n d}}, \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 506, + 696, + 890, + 744 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\mathbf{R}$ denotes the base resizer (e.g. bilinear) and $\\{\\mathbf{W}_1, \\mathbf{W}_2, \\dots, \\mathbf{W}_k\\}$ represents the low-pass filter basis. We define $\\mathbf{W}_{\\ell}$ as a positive row-stochastic matrix [27] of size $n \\times n$ , with $n$ representing the number of pixels in the vectorized input image $\\mathbf{x}$ . Note that we assume $\\mathbf{W}_{k+1} = \\mathbf{I}$ , where $\\mathbf{I}$ is the identity matrix. Each layer in Eq. (2) (see Fig. 2) uses a difference of the filters to decompose the image into different detail layers (bandpass filtering).", + "bbox": [ + 496, + 750, + 890, + 869 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Without loss of generality, we choose the Gaussian kernel as our base filter, and generate the filter bank by an iter-", + "bbox": [ + 498, + 869, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "6879", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "ative application of the same base filter as $\\mathbf{W}_{\\ell} = \\mathbf{W}^{k - \\ell +1}$ with $\\mathbf{W}$ being a Gaussian filter with standard deviation 1. Note that the iterative application of the low-pass filter results in a smoother image. The filtered subband image $(\\mathbf{W}_{\\ell} - \\mathbf{W}_{\\ell +1})\\mathbf{x}$ in brach $\\ell$ is fed into the base resizer to produce the target resolution layer. We add trainable scaling and bias parameters $(\\alpha_{\\ell},\\beta_{\\ell})$ per layer to modulate and shift the resized response. Then, a nonlinearity function $\\sigma$ (e.g., tanh) is applied on the resulting image layer, and finally the output is added to the base resized image. Note that the scaling factor $\\alpha_{\\ell}$ controls the amount of detail boosted or suppressed in layer $l$ of the resizer, and the bias parameter $\\beta_{\\ell}$ controls the mean shift.", + "bbox": [ + 75, + 89, + 472, + 286 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "It is worth pointing out that in this framework, only the scalar and the bias values in the residual layers are trainable, meaning that for $k = 3$ , there are only six trainable parameters, and the overall computational cost is only applying 4 bilinear resizers and 3 Gaussian filters. Note that the term \"Laplacian\" refers to an interpretation of the filtering structure in Fig. 2 that can be written as a summation of Laplacian operators, namely $\\mathbf{L}_{\\ell} = \\mathbf{I} - \\mathbf{W}_{\\ell}$ . More explicitly, for a linear activation, the resulting image $\\mathbf{y}$ can be expressed as a Laplacian form [43]:", + "bbox": [ + 75, + 287, + 472, + 439 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {y} = \\gamma_ {0} \\mathbf {R} (\\mathbf {x}) + \\gamma_ {1} \\mathbf {R} (\\mathbf {L} _ {1} \\mathbf {x}) + \\dots + \\gamma_ {k} \\mathbf {R} (\\mathbf {L} _ {k} \\mathbf {x}) + \\delta , \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 93, + 448, + 468, + 465 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Applications in Vision Tasks", + "text_level": 1, + "bbox": [ + 76, + 472, + 331, + 489 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "While theoretically the resizer can be a drop-in replacement of the default resizer anywhere in the data generation and machine learning pipeline, we mainly demonstrate its ability to learn more informative thumbnail images for downstream recognition and detection tasks, which account for most of the practical use cases. We showcase the impact of MULLER by jointly training it with the backbone, where the resizer takes a higher-resolution image from the data pipeline and downscales it to lower-size before feeding as the model inputs. Since the proposed resizer is strongly regularized by its design, it needs no extra intermediate loss to train. The resizer is also task agnostic as no specific changes are needed to train with it in any framework on any vision or even vision-language tasks.", + "bbox": [ + 75, + 496, + 472, + 708 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 720, + 209, + 738 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We validate the performance of our proposed MULLER resizer on several competitive vision tasks on which resolution plays an important role on performance, including image classification, object detection and segmentation, and image quality assessment. In order to showcase the impact of MULLER, our main experiments include the state-of-the-art vision Transformer model MaxViT [50] as the baseline. We first demonstrate the performance of this baseline", + "bbox": [ + 75, + 744, + 468, + 867 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "model by co-training it with MULLER. Then, we show that MULLER can be effective with other backbones such as ResNet [11], MobileNet-v2 [35] and EfficientNet-B0 [46]. In all the experiments, we use 2 layers in MULLER with Gaussian kernel size 5 and standard deviation 1. We use Tensorflow's default resizing as the base resizing. More experimental details can be found in supplementary materials.", + "bbox": [ + 496, + 90, + 890, + 198 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Main Experiments on ImageNet Classification", + "text_level": 1, + "bbox": [ + 498, + 209, + 888, + 224 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We demonstrate the efficacy of the MULLER resizer on the standard, but most competitive ImageNet-1K classification task [15]. We take a top-performing vision Transformer, MaxViT [50], as the backbone model, and pre-train it on ImageNet-1K at $224 \\times 224$ resolution for 300 epochs. Instead of directly fine-tuning at higher resolution (e.g., 384 or 512) like previous practices [8,9,24,50], we jointly fine-tune the backbone with the MULLER resizer plugged before the stem layers. We set input and output resolutions as 512 and 224 for MULLER in the ImageNet experiments.", + "bbox": [ + 496, + 233, + 890, + 383 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "ImageNet-1K. The main results on ImageNet-1K classification are shown in Tab. 1. Note that we include all the state-of-the-art models trained to their highest possible accuracy reported in the original papers. For better visualization, we draw the accuracy vs. FLOPs and accuracy vs. inference-latency scaling curves in Fig. 3, respectively. As may be seen, MaxViT powered by the MULLER resizer sets a new state-of-the-art top-1 accuracy $85.68\\%$ with only 43.9B FLOPs among all the compared models trained at 224x224. MULLER improves at an average of 0.49 accuracy across the four MaxViT variants. In terms of actual inference time, MaxViT with MULLER exceeds among all the models trained at various resolution - equivalently, it can save $36\\%$ latency to achieve $\\sim 85.7\\%$ accuracy.", + "bbox": [ + 496, + 385, + 892, + 597 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "ImageNet-21K and JFT. To demonstrate the scaling properties of the MULLER resizer with respect to data size, in Tab. 2 we report the results of the models pre-trained on ImageNet-21K and JFT-300M [38], respectively. It can be seen that with ImageNet-21k pretraining, the finetuned MaxViT with MULLER $_{512 \\rightarrow 224}$ gains $0.8\\%$ , $0.6\\%$ , and $0.7\\%$ accuracy over directly finetuning without resizer for B, L, and XL models, respectively. Similarly for JFT-300M pretraining, those numbers are $0.8\\%$ , $0.7\\%$ , and $0.7\\%$ . It indicates that when finetuning with MULLER, MaxViT scales consistently when data size increases from ImageNet-1k up to JFT-300M.", + "bbox": [ + 496, + 598, + 890, + 779 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We further observe that for larger models and larger training sets, the backbone can benefit even more through seeing larger input images. Thus, we also report the performance of training with $\\mathrm{MULLER}_{576\\rightarrow 288}$ . We can see that it further boosts the performance by an average of $0.4\\sim 0.5\\%$ across the board for both 21K and JFT. Remarkably, MaxViT-XL with $\\mathrm{MULLER}_{576\\rightarrow 288}$ achieves $89.16\\%$ top-1 accuracy with only 162.9B FLOPs.", + "bbox": [ + 496, + 780, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_footnote", + "text": "1Note that MULLER is not limited to downscaling, and in fact should the original image data be low resolution, it can learn to upscale as well.", + "bbox": [ + 75, + 875, + 468, + 902 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "6880", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "table", + "img_path": "images/6f979b410b1fed5f0abda26c9ccd68a6f8ae4f3af751d1aa132fb87a3c07b0eb.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ModelEval sizeParamsFLOPsThr (img/s)IN-1K top-1 acc
EffNetV2-S [47]38424M8.8B666.683.9
EffNetV2-M [47]48055M24.0B280.785.1
ConvNeXt-T [25]22429M4.5B77482.1
ConvNeXt-S [25]22450M8.7B447.183.1
ConvNeXt-B [25]22489M15.4B292.183.8
ConvNeXt-L [25]224198M34.4B146.884.3
ViT-B/32 [9]38486M55.4B85.977.9
ViT-B/16 [9]384307M190.7B27.376.5
Swin-T [24]22429M4.5B755.281.3
Swin-S [24]22450M8.7B436.983.0
Swin-B [24]22488M15.4B278.183.5
CSwin-B [8]22423M4.3B70182.7
CSwin-B [8]22435M6.9B43783.6
CSwin-B [8]22478M15.0B25084.2
CoAtNet-0 [7]22425M4.2B52681.6
CoAtNet-1 [7]22425M4.2B33683.3
CoAtNet-2 [7]22475M15.7B247.784.1
CoAtNet-3 [7]224168M34.7B163.384.5
MaxViT-T22431M5.6B350.483.62
+MULLER512→22422431M5.63B349.683.95
MaxViT-S22469M11.7B242.584.45
+MULLER512→22422469M11.73B241.484.95
MaxViT-B224120M23.4B133.684.95
+MULLER512→224224120M23.43B133.085.58
MaxViT-L224212M43.9B99.485.17
+MULLER512→224224212M43.93B99.385.68
", + "bbox": [ + 78, + 88, + 472, + 518 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Table 1. Performance comparison under the ImageNet-1K setting. MULLER $_{\\mathrm{A} \\rightarrow \\mathrm{B}}$ denote that MULLER resizes from A to B, where the backbone takes images of size B. FLOPs counts the total computation of the resolver and backbone. Throughput (Thr) is measured on a single V100 GPU with batch size 16, following [24,25,47]. $\\bullet$ , $\\diamond$ , and $\\diamond$ denote ConvNets, Transformers, and hybrid models, respectively.", + "bbox": [ + 75, + 529, + 468, + 636 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We also examine the generalization of the resizer across different model variants. We found that the learned weights in MULLER are very close across different variants, and the transferring results are as effective as the original training. Detailed results are in the supplementary materials. Note that we present our generalization experiments across different backbones in the next section.", + "bbox": [ + 75, + 652, + 468, + 758 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Different Backbones", + "text_level": 1, + "bbox": [ + 76, + 770, + 272, + 786 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Main results. To explore the resizer beyond the MaxViT architecture, we selected some widely used backbones including ResNet-50 [11], EfficientNet-B0 [46], and MobileNetv2 [35]. Our results are presented in Tab. 3. We also make comparisons with the resizer of Talebi et al. [45]. We observed that the proposed resizer improves the performance of the baseline backbones consistently. Also compared to", + "bbox": [ + 75, + 794, + 470, + 902 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/978247de0b4f8035fa63b6c7a95cf301ff15da7578d21d60bc27f360adfa9c59.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 506, + 92, + 883, + 306 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/d3d7c435ed39b86c6773f1fdc0ea9c12e76a14857b4ce25423ecffb23851c375.jpg", + "image_caption": [ + "Figure 3. Model FLOPs (top), and Inference Latency (bottom) performance comparison of state-of-the-art vision backbones on ImageNet-1K. We show that MaxViT trained with MULLER resizer yielded the best accuracy vs. computation and accuracy vs. inference-cost tradeoff. Note that top figure includes only $224 \\times 224$ models whereas the bottom figures include the best possible performance curves among various training size. Inference time is calculated by the throughput in Tab. 1." + ], + "image_footnote": [], + "bbox": [ + 508, + 313, + 885, + 532 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "[46], MULLER requires a significantly lower number of FLOPs (two orders-of-magnitude), and in some cases such as MobileNet-v2 and EfficientNet-B0 it outperforms [45]. These results also indicate that MULLER improves over baseline resizers low the FLOPs regime as well.", + "bbox": [ + 496, + 700, + 890, + 775 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Cross-model Generalization. In order to examine the generalizability of MULLER, we evaluate classification models with resizers that are trained with other backbones. To this end, we first present the learned resizer parameters for each backbone, and then discuss the classification performances.", + "bbox": [ + 496, + 777, + 890, + 853 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Results in Tab. 4 represent the learned MULLER parameters (see Eq. 2) for each backbone model trained on ImageNet-1k. We observed that (1) performance of the clas", + "bbox": [ + 496, + 854, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "6881", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/8eed22349c161fcf107b812a22329b20f7d2c211108814ebdef49148532e5a81.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ModelEval sizeParamsFLOPsIN-1K top-1 acc.
21K-ptJFT-pt
BiT-R-101x3 [14]384388M204.6B84.4-
BiT-R-152x4 [14]480937M840.5B85.4-
EffNetV2-L [47]480121M53.0B86.8-
EffNetV2-XL [47]512208M94.0B87.3-
ConvNeXt-L [25]384198M101.0B87.5-
ConvNeXt-XL [25]384350M179.0B87.8-
NFNet-F4+ [2]512527M367B-89.20
ViT-B/16 [9]38487M55.5B84.0-
ViT-L/16 [9]384305M191.1B85.2
ViT-L/16 [9]512305M364B-87.76
ViT-H/14 [9]518632M1021B-88.55
HaloNet-H4 [52]51285M-85.8-
SwinV2-B [24]38488M-87.1-
SwinV2-L [24]384197M-87.7-
CvT-W24 [55]384277M193.2B87.7-
R+ViT-L/16 [9]384330M--87.12
CoAtNet-3 [7]384168M107.4B87.688.52
CoAtNet-3 [7]512168M214B87.988.81
CoAtNet-4 [7]512275M360.9B88.189.11
MaxViT-B224119M23.4B86.6387.05
+MULLER512→224224119M23.4B87.4087.82
+MULLER576→288288119M40.6B87.9288.39
MaxViT-L224212M43.9B86.8687.72
+MULLER512→224224212M43.9B87.4888.43
+MULLER576→288288212M73.4B87.9488.87
MaxViT-XL224475M97.8B87.2588.06
+MULLER512→224224475M97.8B87.9088.74
+MULLER576→288288475M162.9B88.3189.16
MaxViT-B512119M138.3B88.3888.82
MaxViT-L512212M245.2B88.4689.41
MaxViT-XL512475M535.2B88.7089.53
", + "bbox": [ + 76, + 87, + 472, + 597 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "sification models are more sensitive to $\\alpha_{1}$ than $\\alpha_{2}$ , and (2) the learned bias values are relatively small, meaning the resizer does not significantly shift the mean of each residual image layer. Note that $|\\alpha_{\\ell}| > 1$ means the image details represented by the $\\ell$ -th layer are boosted, whereas $|\\alpha_{\\ell}| < 1$ has the opposite effect.", + "bbox": [ + 75, + 715, + 468, + 808 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To quantify generalizability of the resizer, we used the learned parameters in Tab. 4 to evaluate different backbones. As for different backbones, Tab. 5 shows that one model leads to classification performance that is in the average proximity of 0.15 from the best top-1 accuracy. We believe this can be explained by the fact that MULLER is a", + "bbox": [ + 75, + 809, + 468, + 901 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/1c6db74d6dad84e10fe143a7a7cfc0a6185216a806349f87bd13405a12576ba9.jpg", + "table_caption": [ + "Table 2. Performance comparison for large-scale data regimes: ImageNet-21K and JFT pretrained models. We report results using two different settings: $\\mathrm{MULLER}_{512\\rightarrow 224}$ and $\\mathrm{MULLER}_{576\\rightarrow 288}$ respectively, as we observe that on larger models and larger training sets, the backbone benefits more by seeing larger inputs." + ], + "table_footnote": [], + "table_body": "
ModelSizeFLOPstop-1 acc.
EffNet-B0 [46]2240.39B77.1
+ [45]512→2242242.63B77.9
+MULLER512→2242240.42B78.2
MobileNet-v2 [35]2240.60B70.5
+ [45]512→2242242.84B71.5
+MULLER512→2242240.63B71.8
ResNet-50 [11]2246.97B75.3
+ [45]512→2242249.33B76.2
+MULLER512→2242247.0B76.2
", + "bbox": [ + 535, + 87, + 859, + 247 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/4eeb138f1280423fde695a4de0db5459d8e234a9622777746fe389c12318aee3.jpg", + "table_caption": [ + "Table 3. Performance comparison under ImageNet-1K setting with different backbones." + ], + "table_footnote": [], + "table_body": "
Modelα1β1α2β2
EffNet-B0 [46]1.7150.088-8.410.001
MobileNet-v2 [35]1.4800.174-5.25-0.058
ResNet-50 [11]1.892-0.014-11.2950.003
", + "bbox": [ + 514, + 301, + 879, + 369 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/c86241d93a9ba2539409867ff62b6de7b59b5e12d3bd20addf42852956bfb8cd.jpg", + "table_caption": [ + "Table 4. The learned MULLER parameters for different backbone models train on ImageNet-1k." + ], + "table_footnote": [], + "table_body": "
ModelEffNet-B0MobileNet-v2ResNet-50
MULLEREffNet78.271.675.9
MULLERMobileNet78.071.876.0
MULLERResNet78.171.776.2
", + "bbox": [ + 506, + 425, + 887, + 494 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 5. Cross-model validation of the MULLER resolver for ImageNet-1K on different backbones.", + "bbox": [ + 498, + 503, + 890, + 532 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "constrained model with only 4 trainable parameters. Also, it is important to highlight that in contrast to the resizer in [45], MULLER does not require fine-tuning.", + "bbox": [ + 496, + 550, + 890, + 595 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Impact of Aliasing. It has been shown that aliasing may impact the performance of some deep vision models [29,51]. It is worth mentioning that the results presented in this section are based on anti-aliased images. More specifically, we used the AREA downscaling method in TensorFlow to produce $512^{2}$ inputs to MULLER. We observed that while removing anti-aliasing does not hamper the overall performance gain obtained by MULLER, the learned parameters may differ from Tab. 4. We will present our results without anti-aliasing in the supplementary material.", + "bbox": [ + 496, + 595, + 892, + 746 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Downstream tasks", + "text_level": 1, + "bbox": [ + 500, + 756, + 678, + 770 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Object Detection and Instance Segmentation. We evaluated the performance of MULLER on COCO2017 [21] for object bounding box detection and instance segmentation tasks with a two-stage cascaded Mask-RCNN framework [31]. We warm start the MaxViT backbone using checkpoints pretrained on ImageNet-1K, then finetune the whole model including the resizing on COCO.", + "bbox": [ + 496, + 779, + 890, + 883 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Tab. 6 summarizes the object detection and instance seg", + "bbox": [ + 519, + 886, + 890, + 901 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "6882", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/690f887d496060f1af67a9b4e1d04c9f71e96ea2143879ada47ab4fc4648d04d.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
BackboneResolutionAP\\( AP_{50} \\)\\( AP_{75} \\)\\( AP^m \\)\\( AP_{50}^m \\)\\( AP_{75}^m \\)FLOPs
•ResNet-50 [11]1280×80046.364.350.540.161.743.4739B
•X101-32 [56]1280×80048.166.552.441.663.945.2819B
•X101-64 [56]1280×80048.366.452.341.764.045.1972B
•ConvNeXt-T [25]1280×80050.469.154.843.766.547.3741B
•ConvNeXt-S [25]1280×80051.970.856.545.068.449.1827B
•ConvNeXt-B [25]1280×80052.771.357.245.668.949.5964B
○Swin-T [24]1280×80050.469.254.743.766.647.3745B
○Swin-S [24]1280×80051.970.756.345.068.248.8838B
○Swin-B [24]1280×80051.970.556.445.068.148.9982B
○UViT-T [6]896×89651.170.456.243.667.747.2613B
○UViT-S [6]896×89651.470.856.244.168.248.0744B
○UViT-B [6]896×89652.572.057.644.368.748.3975B
○MaxViT-T640×64049.969.954.642.766.646.4379B
○+MULR896→640640×64050.570.755.043.167.046.7379B
○MaxViT-S640×64050.570.255.343.367.346.8432B
○+MULR896→640640×64050.870.455.543.567.747.1432B
○MaxViT-B640×64051.671.356.144.168.547.7543B
○+MULR896→640640×64052.371.557.044.768.948.7543B
○MaxViT-T896×89652.171.956.844.669.148.4475B
○MaxViT-S896×89653.172.558.145.469.849.5595B
○MaxViT-B896×89653.472.958.145.770.350.0856B
", + "bbox": [ + 76, + 88, + 472, + 412 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "mentation results comparing state-of-the-art ConvNets and vision Transformers. AP and $\\mathrm{AP}^m$ denote box and mask average precision. We report the train and evaluation resolutions as well as their corresponding FLOPs as reference for model complexity. It may be seen that MaxViT suffers from noticeable performance drop if training resolution is lower. However, we observed that training with the MULLER resized can further improve the performance across the board. Specifically, on MaxViT-B at $640 \\times 640$ , finetuning with MULLER gains 0.7 AP and 0.6 mask AP on the COCO validation set without any FLOPs overhead.", + "bbox": [ + 75, + 501, + 468, + 667 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Image Quality Assessment. We base our experiment on the AVA dataset [28], which includes 250K images rated by amateur photographers. Each image in the dataset is associated with a histogram of ratings from an average of 200 raters. Image quality and aesthetic assessment is a task that is sensitive to downscaling [13], as downscaling may negatively impact visual quality attributes such as sharpness. We use the Earth Mover's Distance (EMD) as our training loss, similar to previous work of [44].", + "bbox": [ + 75, + 670, + 468, + 808 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Our results are shown in Tab. 7. We report the Pearson linear correlation coefficient (PLCC) of the predicted and ground truth mean ratings as our evaluation metric. As can be seen, the proposed resizer improves the performance of MaxViT beyond the existing methods such as MUSIQ [13]. Note that in contrast to MUSIQ which uses multi-scale in", + "bbox": [ + 75, + 809, + 470, + 901 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/45d292995585b974ae6956b5269b79b88dc47e62382eb6db872bf7a914bbefd6.jpg", + "table_caption": [ + "Table 6. Comparison of two-stage object detection and instance segmentation on COCO2017. All models are pretrained on ImageNet-1K." + ], + "table_footnote": [], + "table_body": "
ModelSizeParamsPLCC↑
•NIMA [44]22456M0.636
•+ [45]512→22422456M0.680
•EffNet-B0 [46]2245.3M0.642
•+ [45]512→2242245.3M0.650
•AFDC [5]22444.5M0.671
○ViT-S/32 [13]38422M0.665
○ViT-B/32 [13]38488M0.664
○MUSIQ [13]224~51227M0.720
◇MaxViT-T22431M0.707
◇+MULLER512→22422431M0.729
", + "bbox": [ + 540, + 88, + 856, + 263 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/614a192052e52b036b5bc3b16c03482abeb656c1c41a272f2cb9dafa529281c4.jpg", + "table_caption": [ + "Table 7. Image aesthetic assessment results on the AVA benchmark [28]. PLCC represents the Pearson's linear correlation coefficient." + ], + "table_footnote": [], + "table_body": "
nlayersksizestdTop-1 AccFLOPs
251.085.5824.23B
351.085.5224.24B
451.085.5024.25B
651.085.5924.27B
231.085.4824.23B
271.085.5724.24B
251.585.5624.24B
252.085.5324.24B
", + "bbox": [ + 535, + 333, + 857, + 478 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/0c48dddca52a4028d110833cceb867775a55f080b942e713a4c40e745be67485.jpg", + "table_caption": [ + "Table 8. Hyperparameter sweep for MULLER." + ], + "table_footnote": [], + "table_body": "
input sizeoutput sizeTop-1 AccFLOPs
38422485.4524.22B
51222485.5824.23B
76822485.5624.26B
51238486.4274.25B
76838486.4474.28B
76851286.68138.57B
102451286.67138.60B
", + "bbox": [ + 524, + 518, + 867, + 647 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 9. Effects of input and output size for MULLER using MaxViT-Base as test backkBone. Note that the output size is the image size seen by the backbone.", + "bbox": [ + 498, + 657, + 890, + 703 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "put augmentations, MULLER+MaxViT only requires a single low-resolution input from the resizing.", + "bbox": [ + 498, + 729, + 890, + 762 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4. Ablation", + "text_level": 1, + "bbox": [ + 500, + 771, + 604, + 786 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Hyperparameters. There are three hyperparameters in the design of MULLER: $\\{k, hsize, stddev\\}$ , which denote the number of layers, the kernel size of the Gaussian filters $\\{\\mathbf{W}_1, \\mathbf{W}_2, \\dots, \\mathbf{W}_k\\}$ , and the standard deviation of the Gaussian filters. To understand the effect of these hyperparameters, we conduct an ablation study. As shown in Tab. 8, we found that MULLER is quite insensitive to the selection", + "bbox": [ + 496, + 794, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "6883", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/8b9c5c1238018d1e12adef7cddd12a96661bfe1f16778e243d0d080f96e67335.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 107, + 88, + 330, + 222 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/a7b962ec181b2d97062e6d654a552df3ac8e697c6595e933086305a40939e6d6.jpg", + "image_caption": [ + "(a) Original" + ], + "image_footnote": [], + "bbox": [ + 107, + 222, + 331, + 354 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/e786e0e5496ae7cca9e8ea764837dfc4dd73d1e036eac00bdc68d5641c302f1c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 334, + 88, + 506, + 220 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/8134e7efcf639f24606e45fc147c20a6f0440d32eb38c749d40319061779e355.jpg", + "image_caption": [ + "(b) Default resizer" + ], + "image_footnote": [], + "bbox": [ + 334, + 222, + 506, + 354 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/c011fae887eaeb90b297ea9a748ddde12c0cdb3edacdf5d84d7aa4f09007512c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 509, + 88, + 681, + 220 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/1dbce26ee9e4edf0eddc9af9cc18ba6b6759ba29f36ba6d3ff51c8c3b1b77e1a.jpg", + "image_caption": [ + "(c) Learned resizer", + "Figure 4. Visualizations of the learned MULLER resizer for ResNet-50. Here the default resizer is an (anti-aliased) AREA resizer in Tensorflow. (d) shows the difference of the learned and the default resizers." + ], + "image_footnote": [], + "bbox": [ + 509, + 222, + 681, + 354 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/672abccec551ea0d900c31bcd304faf54d4d870d59f552714e807fe2487eb762.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 684, + 88, + 857, + 220 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/9eaf1819e7835e952cbf55e12298922016bdd0afabd7a22bb6fc2730ef235ddf.jpg", + "image_caption": [ + "(d) Difference" + ], + "image_footnote": [], + "bbox": [ + 684, + 222, + 857, + 354 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "of parameters, and thus we recommend to use a simple set of parameters to save computation.", + "bbox": [ + 75, + 422, + 468, + 454 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Effects of image size. It is known that image size can significantly affect the recognition performance. We evaluate the effect of varying input and output sizes of MULLER using MaxViT-B in Tab. 9. Note that the output size of MULLER is indeed the size seen by the backbone, so higher output size typically corresponds to improved accuracy. We observe that using higher input resolutions (e.g., $3 \\times$ ) for MULLER does not yield any further performance gain beyond the baseline setting. Nonetheless, we find that adopting a reasonably large resolution (e.g. $1.6 \\sim 2.5 \\times$ ) is necessary to achieve the expected performance. It is worth highlighting that this is perhaps impacted by the original resolution of images in the benchmark dataset.", + "bbox": [ + 75, + 457, + 470, + 652 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.5. Visualization", + "text_level": 1, + "bbox": [ + 76, + 676, + 212, + 690 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We visualize the behavior of the learned resizer in Fig. 4. As can be seen, the MULLER resizer is learned to boost details or textures of the images, while also enhancing the image contrast. These effects can preserve more visual information in the downscaled images over naive resizing, thus making the classification model learn better. As compared to the previous less-controlled resizer [45], MULLER achieves a better balance of human and machine perceptual qualities, due to the strong regularization imbued in its Laplacian-inspired design. We also point out that training MULLER with aliased inputs may produce relatively less sharper images in comparison to Fig. 4. We refer the reader to the supplementary material for visual examples.", + "bbox": [ + 75, + 703, + 468, + 900 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Concluding Remarks", + "text_level": 1, + "bbox": [ + 500, + 421, + 702, + 439 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this paper, we introduce MULLER, an extremely simple and light learned resizer, using multilayer Laplacian decomposition. The proposed resizer only contains 4 trainable parameters with negligible training and inference costs. This allows deploying the resizer as a thumbnail generator to produce optimally downscaled images for sending to remote inference servers, or alternatively as a server side resizer that reduces the inference cost without the necessity of changing the backbone architecture. We show that MULLER not only pushes forward the limit of the state-of-the-art vision Transformer MaxViT on ImageNet classification, but it also consistently improves across a range of widely used architectures, including EfficientNet, MobileNet, and ResNet. Additionally, we provide experiments to substantiate the efficacy of MULLER for various downstream tasks, such as object detection, segmentation, and image quality assessment. As compared to previous methods, MULLER enjoys remarkable generalization ability, owing to the strong regularization provided by its multilayer bandpass design. We believe that our work will inspire future research in this critically important direction: how to better preprocess images for vision tasks.", + "bbox": [ + 496, + 446, + 890, + 779 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Limitations and future works. We note that if the higher-resolution inputs fail to boost the performance of an specific task, we cannot reasonably expect the learned resizer to provide a substantial performance boost either. Another potential future direction is to train a universal learned resizer that can be a drop-in replacement of the off-the-shelf resizers in existing machine learning frameworks, without necessitating the joint re-training of the backbones.", + "bbox": [ + 496, + 779, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "6884", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Martín Abadi, Ashish Agarwal, Paul Barham, Eugene Brevdo, Zhifeng Chen, Craig Citro, Greg S Corrado, Andy Davis, Jeffrey Dean, Matthieu Devin, et al. Tensorflow: Large-scale machine learning on heterogeneous distributed systems. arXiv preprint arXiv:1603.04467, 2016. 1", + "[2] Andy Brock, Soham De, Samuel L Smith, and Karen Simonyan. High-performance large-scale image recognition without normalization. In International Conference on Machine Learning, pages 1059-1071. PMLR, 2021. 6", + "[3] Li-Heng Chen, Christos G Bampis, Zhi Li, Lukáš Krasula, and Alan C Bovik. Estimating the resize parameter in end-to-end learned image compression. arXiv preprint arXiv:2204.12022, 2022. 2, 3", + "[4] Li-Heng Chen, Christos G Bampis, Zhi Li, Joel Sole, and Alan C Bovik. A progressive architecture for learned fractional downsampling. In 2021 Picture Coding Symposium (PCS), pages 1-5. IEEE, 2021. 2, 3", + "[5] Qiuyu Chen, Wei Zhang, Ning Zhou, Peng Lei, Yi Xu, Yu Zheng, and Jianping Fan. Adaptive fractional dilated convolution network for image aesthetics assessment. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14114-14123, 2020. 7", + "[6] Wuyang Chen, Xianzhi Du, Fan Yang, Lucas Beyer, Xiaohua Zhai, Tsung-Yi Lin, Huizhong Chen, Jing Li, Xiaodan Song, Zhangyang Wang, and Denny Zhou. A simple single-scale vision transformer for object localization and instance segmentation. CoRR, abs/2112.09747, 2021. 7", + "[7] Zihang Dai, Hanxiao Liu, Quoc Le, and Mingxing Tan. Coatnet: Marrying convolution and attention for all data sizes. Advances in Neural Information Processing Systems, 34, 2021. 5, 6", + "[8] Xiaoyi Dong, Jianmin Bao, Dongdong Chen, Weiming Zhang, Nenghai Yu, Lu Yuan, Dong Chen, and Baining Guo. Cswin transformer: A general vision transformer backbone with cross-shaped windows. arXiv preprint arXiv:2107.00652, 2021. 4, 5", + "[9] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020.4,5,6", + "[10] Muhammad Haris, Greg Shakhnarovich, and Norimichi Ukita. Task-driven super resolution: Object detection in low-resolution images. In Neural Information Processing: 28th International Conference, ICONIP 2021, Sanur, Bali, Indonesia, December 8-12, 2021, Proceedings, Part V 28, pages 387-395. Springer, 2021. 3", + "[11] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 1, 4, 5, 6, 7", + "[12] Gao Huang, Zhuang Liu, Laurens Van Der Maaten, and Kilian Q Weinberger. Densely connected convolutional networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4700-4708, 2017. 1" + ], + "bbox": [ + 78, + 114, + 470, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[13] Junjie Ke, Qifei Wang, Yilin Wang, Peyman Milanfar, and Feng Yang. Musiq: Multi-scale image quality transformer. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 5148-5157, 2021. 7", + "[14] Alexander Kolesnikov, Lucas Beyer, Xiaohua Zhai, Joan Puigcerver, Jessica Yung, Sylvain Gelly, and Neil Houlsby. Big transfer (bit): General visual representation learning. In European conference on computer vision, pages 491-507. Springer, 2020. 6", + "[15] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E Hinton. Imagenet classification with deep convolutional neural networks. Advances in neural information processing systems, 25, 2012. 1, 4", + "[16] Boyi Li, Xiulian Peng, Zhangyang Wang, Jizheng Xu, and Dan Feng. End-to-end united video dehazing and detection. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 32, 2018. 3", + "[17] Boyi Li, Wenqi Ren, Dengpan Fu, Dacheng Tao, Dan Feng, Wenjun Zeng, and Zhangyang Wang. Benchmarking single-image dehazing and beyond. IEEE Transactions on Image Processing, 28(1):492-505, 2018. 2", + "[18] Siyuan Li, Iago Bruno Araujo, Wenqi Ren, Zhangyang Wang, Eric K Tokuda, Roberto Hirata Junior, Roberto Cesar-Junior, Jiawan Zhang, Xiaojie Guo, and Xiaochun Cao. Single image deraining: A comprehensive benchmark analysis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3838-3847, 2019. 2", + "[19] Yinxiao Li, Pengchong Jin, Feng Yang, Ce Liu, Ming-Hsuan Yang, and Peyman Milanfar. Comisr: Compression-informed video super-resolution. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2543-2552, 2021. 2", + "[20] Yue Li, Dong Liu, Houqiang Li, Li Li, Zhu Li, and Feng Wu. Learning a convolutional neural network for image compact-resolution. IEEE Transactions on Image Processing, 28(3):1092-1107, 2018. 2", + "[21] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In European conference on computer vision, pages 740-755. Springer, 2014. 6", + "[22] Ding Liu, Bihan Wen, Xianming Liu, Zhangyang Wang, and Thomas S Huang. When image denoising meets high-level vision tasks: A deep learning approach. arXiv preprint arXiv:1706.04284, 2017. 3", + "[23] Feng Liu, Ronghang Zhu, Dan Zeng, Qijun Zhao, and Xiaoming Liu. Disentangling features in 3d face shapes for joint face reconstruction and recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5216-5225, 2018. 3", + "[24] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10012-10022, 2021. 1, 4, 5, 6, 7", + "[25] Zhuang Liu, Hanzi Mao, Chao-Yuan Wu, Christoph Feichtenhofer, Trevor Darrell, and Saining Xie. A convnet for the 2020s. arXiv preprint arXiv:2201.03545, 2022. 5, 6, 7" + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "6885", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[26] Zhuang Liu, Tinghui Zhou, Hung-Ju Wang, Zhiqiang Shen, Bingyi Kang, Evan Shelhamer, and Trevor Darrell. Transferable recognition-aware image processing. arXiv preprint arXiv:1910.09185, 2019. 3", + "[27] Peyman Milanfar. A tour of modern image filtering: New insights and methods, both practical and theoretical. IEEE signal processing magazine, 30(1):106-128, 2012. 3", + "[28] Naila Murray, Luca Marchesotti, and Florent Perronnin. Ava: A large-scale database for aesthetic visual analysis. In 2012 IEEE conference on computer vision and pattern recognition, pages 2408-2415. IEEE, 2012. 7", + "[29] Gaurav Parmar, Richard Zhang, and Jun-Yan Zhu. On buggy resizing libraries and surprising subtleties in fid calculation. arXiv preprint arXiv:2104.11222, 2021. 2, 6", + "[30] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, Luca Antiga, et al. Pytorch: An imperative style, high-performance deep learning library. Advances in neural information processing systems, 32, 2019. 1", + "[31] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. In C. Cortes, N. Lawrence, D. Lee, M. Sugiyama, and R. Garnett, editors, Advances in Neural Information Processing Systems, volume 28. Curran Associates, Inc., 2015. 6", + "[32] Rachid Riad, Olivier Teboul, David Grangier, and Neil Zeghidour. Learning strides in convolutional neural networks. arXiv preprint arXiv:2202.01653, 2022. 2", + "[33] Avinab Saha, Sandeep Mishra, and Alan C Bovik. Reiaq: Unsupervised learning for image quality assessment in the wild. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5846-5855, 2023. 1", + "[34] Mehdi SM Sajjadi, Bernhard Scholkopf, and Michael Hirsch. Enhancenet: Single image super-resolution through automated texture synthesis. arXiv preprint arXiv:1612.07919, 2016. 2", + "[35] Mark Sandler, Andrew Howard, Menglong Zhu, Andrey Zh-moginov, and Liang-Chieh Chen. Mobilenetv2: Inverted residuals and linear bottlenecks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4510-4520, 2018. 1, 4, 5, 6", + "[36] Vivek Sharma, Ali Diba, Davy Neven, Michael S Brown, Luc Van Gool, and Rainer Stiefelhagen. Classification-driven dynamic image enhancement. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4033-4041, 2018. 3", + "[37] Wenzhe Shi, Jose Caballero, Ferenc Huszár, Johannes Totz, Andrew P Aitken, Rob Bishop, Daniel Rueckert, and Zehan Wang. Real-time single image and video super-resolution using an efficient sub-pixel convolutional neural network. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1874-1883, 2016. 2", + "[38] Chen Sun, Abhinav Shrivastava, Saurabh Singh, and Abhinav Gupta. Revisiting unreasonable effectiveness of data in deep learning era. In Proceedings of the IEEE international conference on computer vision, pages 843-852, 2017. 4" + ], + "bbox": [ + 78, + 90, + 468, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[39] Satoshi Suzuki, Motohiro Takagi, Kazuya Hayase, Takayuki Onishi, and Atsushi Shimizu. Image pre-transformation for recognition-aware image compression. In 2019 IEEE International Conference on Image Processing (ICIP), pages 2686-2690. IEEE, 2019. 3", + "[40] Christian Szegedy, Wei Liu, Yangqing Jia, Pierre Sermanet, Scott Reed, Dragomir Anguelov, Dumitru Erhan, Vincent Vanhoucke, and Andrew Rabinovich. Going deeper with convolutions. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1-9, 2015. 1", + "[41] Christian Szegedy, Vincent Vanhoucke, Sergey Ioffe, Jon Shlens, and Zbigniew Wojna. Rethinking the inception architecture for computer vision. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2818-2826, 2016. 1", + "[42] Hossein Talebi, Damien Kelly, Xiyang Luo, Ignacio Garcia Dorado, Feng Yang, Peyman Milanfar, and Michael Elad. Better compression with deep pre-editing. IEEE Transactions on Image Processing, 30:6673-6685, 2021. 3", + "[43] Hossein Talebi and Peyman Milanfar. Fast multilayer laplacian enhancement. IEEE Transactions on Computational Imaging, 2(4):496-509, 2016. 4", + "[44] Hossein Talebi and Peyman Milanfar. Nima: Neural image assessment. IEEE transactions on image processing, 27(8):3998-4011, 2018. 7", + "[45] Hossein Talebi and Peyman Milanfar. Learning to resize images for computer vision tasks. In Proceedings of the IEEE/CVF international conference on computer vision, pages 497-506, 2021. 2, 3, 5, 6, 7, 8", + "[46] Mingxing Tan and Quoc Le. Efficientnet: Rethinking model scaling for convolutional neural networks. In International conference on machine learning, pages 6105-6114. PMLR, 2019. 1, 4, 5, 6, 7", + "[47] Mingxing Tan and Quoc Le. Efficientnetv2: Smaller models and faster training. In International Conference on Machine Learning, pages 10096-10106. PMLR, 2021. 5, 6", + "[48] Xin Tao, Hongyun Gao, Xiaoyong Shen, Jue Wang, and Jiaya Jia. Scale-recurrent network for deep image deblurring. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 8174-8182, 2018. 2", + "[49] Zhengzhong Tu, Hossein Talebi, Han Zhang, Feng Yang, Peyman Milanfar, Alan Bovik, and Yinxiao Li. Maxim: Multi-axis mlp for image processing. arXiv preprint arXiv:2201.02973, 2022. 2", + "[50] Zhengzhong Tu, Hossein Talebi, Han Zhang, Feng Yang, Peyman Milanfar, Alan Bovik, and Yinxiao Li. Maxvit: Multi-axis vision transformer. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXIV, pages 459-479. Springer, 2022. 1, 2, 4", + "[51] Cristina Vasconcelos, Hugo Larochelle, Vincent Dumoulin, Rob Romijnders, Nicolas Le Roux, and Ross Goroshin. Impact of aliasing on generalization in deep convolutional networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10529-10538, 2021. 6", + "[52] Ashish Vaswani, Prajit Ramachandran, Aravind Srinivas, Niki Parmar, Blake Hechtman, and Jonathon Shlens. Scaling" + ], + "bbox": [ + 501, + 92, + 890, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "6886", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "local self-attention for parameter efficient visual backbones. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12894–12904, 2021. 6", + "[53] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. 1", + "[54] Zhou Wang. Image quality assessment: from error visibility to structural similarity. IEEE transactions on image processing, 13(4):600-612, 2004. 2", + "[55] Haiping Wu, Bin Xiao, Noel Codella, Mengchen Liu, Xiyang Dai, Lu Yuan, and Lei Zhang. Cvt: Introducing convolutions to vision transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 22-31, 2021. 6", + "[56] Saining Xie, Ross Girshick, Piotr Dólár, Zhuowen Tu, and Kaiming He. Aggregated residual transformations for deep neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1492-1500, 2017. 7", + "[57] Runsheng Xu, Jinlong Li, Xiaoyu Dong, Hongkai Yu, and Jiaqi Ma. Bridging the domain gap for multi-agent perception. arXiv preprint arXiv:2210.08451, 2022. 2", + "[58] Runsheng Xu, Hao Xiang, Zhengzhong Tu, Xin Xia, Ming-Hsuan Yang, and Jiaqi Ma. V2x-vit: Vehicle-to-everything cooperative perception with vision transformer. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXXIX, pages 107-124. Springer, 2022. 1", + "[59] Kai Zhang, Wangmeng Zuo, Yunjin Chen, Deyu Meng, and Lei Zhang. Beyond a gaussian denoiser: Residual learning of deep cnn for image denoising. IEEE transactions on image processing, 26(7):3142-3155, 2017. 2", + "[60] Richard Zhang, Phillip Isola, and Alexei A Efros. Colorful image colorization. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part III 14, pages 649-666. Springer, 2016. 2", + "[61] Chen Zhao and Bernard Ghanem. Thumbnet: One thumbnail image contains all you need for recognition. In Proceedings of the 28th ACM International Conference on Multimedia, pages 1506-1514, 2020. 2" + ], + "bbox": [ + 78, + 90, + 468, + 698 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "6887", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MULLER_ Multilayer Laplacian Resizer for Vision/540b48e0-0e9c-4eba-a984-866547201e9c_model.json b/2023/MULLER_ Multilayer Laplacian Resizer for Vision/540b48e0-0e9c-4eba-a984-866547201e9c_model.json new file mode 100644 index 0000000000000000000000000000000000000000..70126d0cd0ce5f4d2e7c42f503dc4c59ecb9fc94 --- /dev/null +++ b/2023/MULLER_ Multilayer Laplacian Resizer for Vision/540b48e0-0e9c-4eba-a984-866547201e9c_model.json @@ -0,0 +1,2169 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.226, + 0.131, + 0.745, + 0.153 + ], + "angle": 0, + "content": "MULLER: Multilayer Laplacian Resizer for Vision" + }, + { + "type": "text", + "bbox": [ + 0.286, + 0.181, + 0.685, + 0.217 + ], + "angle": 0, + "content": "Zhengzhong Tu, Peyman Milanfar, Hossein Talebi \nGoogle Research" + }, + { + "type": "text", + "bbox": [ + 0.382, + 0.22, + 0.59, + 0.234 + ], + "angle": 0, + "content": "zhengzhongtu@gmail.com" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.269, + 0.314, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.302, + 0.474, + 0.74 + ], + "angle": 0, + "content": "Image resizing operation is a fundamental preprocessing module in modern computer vision. Throughout the deep learning revolution, researchers have overlooked the potential of alternative resizing methods beyond the commonly used resize that are readily available, such as nearest-neighbors, bilinear, and bicubic. The key question of our interest is whether the front-end resize affects the performance of deep vision models? In this paper, we present an extremely lightweight multilayer Laplacian resolver with only a handful of trainable parameters, dubbed MULLER resolver. MULLER has a bandpass nature in that it learns to boost details in certain frequency subbands that benefit the downstream recognition models. We show that MULLER can be easily plugged into various training pipelines, and it effectively boosts the performance of the underlying vision task with little to no extra cost. Specifically, we select a state-of-the-art vision Transformer, MaxViT [50], as the baseline, and show that, if trained with MULLER, MaxViT gains up to \\(0.6\\%\\) top-1 accuracy, and meanwhile enjoys \\(36\\%\\) inference cost saving to achieve similar top-1 accuracy on ImageNet-1k, as compared to the standard training scheme. Notably, MULLER's performance also scales with model size and training data size such as ImageNet-21k and JFT, and it is widely applicable to multiple vision tasks, including image classification, object detection and segmentation, as well as image quality assessment. The code is available at https://github.com/google-research/google-research/tree/master/muller." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.769, + 0.21, + 0.785 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Most computer vision problems such as image classification, object detection, video recognition, and image/video generation have seen groundbreaking advancement by deep neural networks-based models that are trained on web-scale, human-curated datasets [11, 12, 15, 15, 24, 33, 35, 40, 41, 46, 53, 58]. In any of the underlining training infrastructures like Tensorflow [1] and PyTorch [30], image resizing" + }, + { + "type": "image", + "bbox": [ + 0.515, + 0.269, + 0.88, + 0.407 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.513, + 0.412, + 0.885, + 0.525 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.541, + 0.895, + 0.648 + ], + "angle": 0, + "content": "Figure 1. Top: our proposed learned resizer can push forward a strong vision Transformer MaxViT [50] by up to \\(0.6\\%\\) top-1 accuracy on ImageNet-1K with no extra inference cost. Results for other backbones are shown in Sec. 4.2. Bottom: demonstration of the learned resizer - with detail-boosted input image, the classification accuracy of the exemplar image has improved." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.672, + 0.895, + 0.793 + ], + "angle": 0, + "content": "is an essential preprocessing step which enables efficient gradient-based training of networks with millions of trainable parameters. Moreover, the factor of image size can sometimes significantly impact the performance of various tasks, particularly those requiring high-resolution prediction. Although neural architectures have been revolutionized by CNNs and Transformers, surprisingly limited attention has been paid to the role of image resizing operations." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Resizing or rescaling refers to the process of changing the resolution of an image, while largely preserving its content for human or machine perception. There are several major reasons for using resizing: (1) The mini-batch gradient-based training scheme requires the same image resolution in a batch, (2) Resizing can help to reduce computational complexity, making it easier and faster to train" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6877" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.471, + 0.198 + ], + "angle": 0, + "content": "and inference neural networks, (3) Smaller images consume lower memory footprint, enabling stable training of large models like Transformers with larger batch-size, (4) Resizing contributes to improving model generalization and robustness by reducing overfitting to specific image size and scales, making the models more flexible and applicable to real-world scenarios." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.2, + 0.47, + 0.337 + ], + "angle": 0, + "content": "Moreover, resizing is an integral component of remote inference frameworks. Typically, to maintain the bandwidth efficiency of the communication network, before sending an image to the inference server, a thumbnail generator downscales the image to a fixed resolution (e.g. 480p). The thumbnail generator can be located on the client side (e.g. smart phone), or it can be part of a cloud storage system. This means that in most cases the inference server does not have access to the original image." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.34, + 0.471, + 0.657 + ], + "angle": 0, + "content": "Basic resizing functions such as nearest-neighbor or bilinear interpolation have long been the go-to options with little to no deliberate consideration in most training software. While these simple methods offer greater simplicity and efficiency, they are not optimized for specific computer vision tasks and may lead to the loss of important visual features or details, which can, sometimes, result in significant performance degradation [29, 45]. To overcome this limitation, researchers have proposed learned resizers (or downsamplers) [3, 45] that leverage the deep neural networks to learn image resizing directly from data, yielding improved performance on several tasks. However, one of the main challenges with these learned resizers is that they often require a large number of parameters, and high computational overhead during training and inference. Note that this is specifically a bottleneck in remote inference where the resize (a.k.a thumbnail generator) is not in the inference server, and may have limited computational resources to run a heavy neural net resolver. Additionally, less-bounded resizers can sometimes be difficult to transfer to new tasks or datasets due to their excessive model capability." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.66, + 0.471, + 0.902 + ], + "angle": 0, + "content": "In this paper, we introduce an incredibly lightweight learned resizer, which we call MULLER, that operates on multilayer Laplacian decomposition of images (see Fig. 2). Our method requires very few parameters and FLOPs, and does not incur any extra training cost, outperforming existing methods in terms of computational efficiency, parameter efficiency, and transferability. We show that it is the ability-to-learn that makes a better resizer, but not the capacity of the resizer - our MULLER resizer only learns four parameters and is more effective than previous complex ones using deep residual blocks [45]. We also demonstrate that our method can be used as a drop-in replacement for off-the-shelf resizing functions on several vision tasks, including classification, object detection and segmentation, and image quality assessment, resulting in significant performance improvements without any extra cost. As shown in Fig. 1," + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.138 + ], + "angle": 0, + "content": "for example, training with the MULLER responder achieves up to \\(0.6\\%\\) performance gain, using a state-of-the-art backbone MaxViT [50] as the testbed. Our contributions are:" + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.147, + 0.892, + 0.193 + ], + "angle": 0, + "content": "- We propose a surprisingly simple and lightweight resolver, that can be used as a drop-in replacement for off-the-shelf resizing functions like bilinear resizing." + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.197, + 0.892, + 0.259 + ], + "angle": 0, + "content": "- We demonstrate its applications to multiple computer vision tasks, including image classification, object detection and segmentation, and image quality assessment, showing superior performance over existing approaches." + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.263, + 0.892, + 0.323 + ], + "angle": 0, + "content": "- Extensive ablation studies, analysis, and visualization results are provided to show the robustness and generalization of the proposed resizer for various model scales, benchmarks, and tasks." + }, + { + "type": "list", + "bbox": [ + 0.501, + 0.147, + 0.892, + 0.323 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.347, + 0.642, + 0.364 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.373, + 0.892, + 0.508 + ], + "angle": 0, + "content": "Resizing in vision. Resizing is a crucial preprocessing step to train deep learning vision models. Due to their simplicity, efficiency and availability, nearest-neighbor and bilinear interpolations are the most widely used resizing methods in both training, inference, and serving. These simple approaches, however, can suffer from detail loss and artifacts, and the degraded image quality might hamper the performance of downstream visual recognition tasks, especially when the resizing factor is large." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.509, + 0.892, + 0.689 + ], + "angle": 0, + "content": "Some recent works have explored to use learning-based methods for image downscaling to enhance the desired content in the resized images from training data [3,4,20,32,45, 61]. For example, the authors of [3,4] proposed a residual CNN module for downscaling, and jointly trained it with an image compression network to generate \"compression-friendly\" representations. [45] introduced a CNN-based learned resizer for various computer vision tasks, including image classification and image quality assessment. Similarly, the idea of learned rescaling has been applied to other computer vision applications [20, 32, 57, 61], showing improved performance in detection and recognition." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.69, + 0.892, + 0.84 + ], + "angle": 0, + "content": "Image processing for machine vision. Image processing or enhancement problems such as super-resolution [19, 37], denoising [59], and deblurring [48, 49] have been longstanding challenges in computer vision. Recent works have focused on building larger-scale, diverse benchmarks, exploring novel model architectures, and improving training techniques. These works aim to produce visually pleasing outputs, often measured by conventional metrics like PSNR or SSIM [54], or through human evaluations, without considering downstream recognition performance of the output." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.841, + 0.892, + 0.901 + ], + "angle": 0, + "content": "There exists a number of works relating image processing to image recognition performance, or machine-oriented image processing. Some works [17, 18, 34, 60] use image recognition accuracy as supplementary metrics besides" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6878" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.135, + 0.088, + 0.817, + 0.238 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.247, + 0.895, + 0.294 + ], + "angle": 0, + "content": "Figure 2. The architecture of the proposed multilayer Laplacian resizer (MULLER). The resizer decomposes the input image into multiple layers of Laplacian residuals and then adds them back to the default resized image. The MULLER resizer is jointly trained with the downstream recognition model." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.313, + 0.473, + 0.555 + ], + "angle": 0, + "content": "visual quality metrics to evaluate the performance of image restoration models. Towards recognition-aware training, [10] proposed to train super-resolution using object detection loss and show promising results over conventional methods. Other works [39, 42] introduce pre-editing networks before image compression to improve compression efficiency without sacrificing classification accuracy. Recently, Liu et al. [26] developed an approach to train the processing models under the objective of image recognition accuracy, and investigated the efficacy of popular preprocessing operations such as super-resolution, denoising, and JPEG-deblocking on improving recognition performance. More similar studies [16, 22, 23, 36] have been conducted to jointly train a processing model like denoising, dehazing, face reconstruction, together with recognition model to achieve better image processing for recognition quality." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.57, + 0.269, + 0.587 + ], + "angle": 0, + "content": "3. Proposed Approach" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.596, + 0.47, + 0.822 + ], + "angle": 0, + "content": "In this section, we introduce our proposed multilayer Laplacian resizer (MULLER, overviewed in Fig. 2), and discuss how we employ it for training several popular vision tasks. Unlike previous proposed resizers [3, 45], we aim to keep the computational cost of the model as low as possible such that it can replace existing resizers (e.g., bilinear) without extra cost, but also there is a notable performance gain. Our proposed approach is different in that (1) it is orders of magnitude faster, hence more scalable (to large image size), (2) it only has a handful of parameters which allows for better generalization, (3) it adds almost no extra training cost to the system. We show that with learning merely a couple of parameters, training with an added resizing module performs as effective as having a heavy downscaling network with several thousand parameter counts." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.833, + 0.226, + 0.848 + ], + "angle": 0, + "content": "3.1. Resizer Model" + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.857, + 0.459, + 0.873 + ], + "angle": 0, + "content": "Image resizing models can be generally formulated as:" + }, + { + "type": "equation", + "bbox": [ + 0.178, + 0.885, + 0.47, + 0.903 + ], + "angle": 0, + "content": "\\[\n\\mathbf {y} = \\mathbf {F} _ {2} \\left(\\mathbf {R} \\left(\\mathbf {F} _ {1} (\\mathbf {x}); h ^ {\\prime}, w ^ {\\prime}\\right)\\right), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.313, + 0.892, + 0.525 + ], + "angle": 0, + "content": "where \\(\\mathbf{R}\\) maps the input image \\(\\mathbf{x}\\) of size \\(h\\times w\\) to an output image of size \\(h^{\\prime}\\times w^{\\prime}\\) by computing the pixel values at the target spatial locations. \\(\\mathbf{F}_1\\) and \\(\\mathbf{F}_2\\) denote optional pre- and post-filtering operations. Typically, \\(\\mathbf{F}_1\\) and \\(\\mathbf{F}_2\\) can be identity functions, and \\(\\mathbf{R}\\) is chosen as a simple interpolation method like nearest-neighbor, bilinear, or bicubic. To learn more powerful resizing, learned resize has been proposed [3,4,45] by applying a base resizer on intermediate neural activations, wherein \\(\\mathbf{F}_1\\) and \\(\\mathbf{F}_2\\) are two designed CNNs applied at the original and output resolutions, respectively. Despite showing promising performance, however, these resize typically suffer from high computational complexity, and thus their net performance gain might be compromised in terms of the overall inference cost." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.531, + 0.755, + 0.547 + ], + "angle": 0, + "content": "3.2. Proposed MULLER Resizer" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.554, + 0.892, + 0.691 + ], + "angle": 0, + "content": "We are inspired by the observations that these different learned resize, if properly regularized, will often learn to enhance edges, details, or sharpness of the image to benefit downstream tasks [3, 4]. To this end, we present to date, the simplest learned resizing model, using multilayer Laplacian decomposition, that is able to achieve 'bandpassed' detail and texture manipulation with only a handful of learnable parameters. Fig. 2 shows the architecture of the proposed MULLER resize. MULLER has the following form:" + }, + { + "type": "equation", + "bbox": [ + 0.508, + 0.697, + 0.892, + 0.745 + ], + "angle": 0, + "content": "\\[\n\\mathbf {z} = \\underbrace {\\mathbf {R} (\\mathbf {x})} _ {\\text {B a s e i m a g e}} + \\sum_ {\\ell = 1} ^ {k} \\underbrace {\\sigma \\left(\\alpha_ {\\ell} \\left(\\mathbf {R} \\left(\\left(\\mathbf {W} _ {\\ell} - \\mathbf {W} _ {\\ell + 1}\\right) \\mathbf {x}\\right) + \\beta_ {\\ell}\\right)\\right)} _ {\\text {E n h a n c e d d e t a i l s i n e a c h s u b b a n d}}, \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.892, + 0.871 + ], + "angle": 0, + "content": "where \\(\\mathbf{R}\\) denotes the base resizer (e.g. bilinear) and \\(\\{\\mathbf{W}_1, \\mathbf{W}_2, \\dots, \\mathbf{W}_k\\}\\) represents the low-pass filter basis. We define \\(\\mathbf{W}_{\\ell}\\) as a positive row-stochastic matrix [27] of size \\(n \\times n\\), with \\(n\\) representing the number of pixels in the vectorized input image \\(\\mathbf{x}\\). Note that we assume \\(\\mathbf{W}_{k+1} = \\mathbf{I}\\), where \\(\\mathbf{I}\\) is the identity matrix. Each layer in Eq. (2) (see Fig. 2) uses a difference of the filters to decompose the image into different detail layers (bandpass filtering)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Without loss of generality, we choose the Gaussian kernel as our base filter, and generate the filter bank by an iter-" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6879" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.09, + 0.473, + 0.287 + ], + "angle": 0, + "content": "ative application of the same base filter as \\(\\mathbf{W}_{\\ell} = \\mathbf{W}^{k - \\ell +1}\\) with \\(\\mathbf{W}\\) being a Gaussian filter with standard deviation 1. Note that the iterative application of the low-pass filter results in a smoother image. The filtered subband image \\((\\mathbf{W}_{\\ell} - \\mathbf{W}_{\\ell +1})\\mathbf{x}\\) in brach \\(\\ell\\) is fed into the base resizer to produce the target resolution layer. We add trainable scaling and bias parameters \\((\\alpha_{\\ell},\\beta_{\\ell})\\) per layer to modulate and shift the resized response. Then, a nonlinearity function \\(\\sigma\\) (e.g., tanh) is applied on the resulting image layer, and finally the output is added to the base resized image. Note that the scaling factor \\(\\alpha_{\\ell}\\) controls the amount of detail boosted or suppressed in layer \\(l\\) of the resizer, and the bias parameter \\(\\beta_{\\ell}\\) controls the mean shift." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.288, + 0.473, + 0.44 + ], + "angle": 0, + "content": "It is worth pointing out that in this framework, only the scalar and the bias values in the residual layers are trainable, meaning that for \\( k = 3 \\), there are only six trainable parameters, and the overall computational cost is only applying 4 bilinear resizers and 3 Gaussian filters. Note that the term \"Laplacian\" refers to an interpretation of the filtering structure in Fig. 2 that can be written as a summation of Laplacian operators, namely \\( \\mathbf{L}_{\\ell} = \\mathbf{I} - \\mathbf{W}_{\\ell} \\). More explicitly, for a linear activation, the resulting image \\( \\mathbf{y} \\) can be expressed as a Laplacian form [43]:" + }, + { + "type": "equation", + "bbox": [ + 0.094, + 0.449, + 0.47, + 0.466 + ], + "angle": 0, + "content": "\\[\n\\mathbf {y} = \\gamma_ {0} \\mathbf {R} (\\mathbf {x}) + \\gamma_ {1} \\mathbf {R} (\\mathbf {L} _ {1} \\mathbf {x}) + \\dots + \\gamma_ {k} \\mathbf {R} (\\mathbf {L} _ {k} \\mathbf {x}) + \\delta , \\tag {3}\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.473, + 0.332, + 0.49 + ], + "angle": 0, + "content": "3.3. Applications in Vision Tasks" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.497, + 0.473, + 0.709 + ], + "angle": 0, + "content": "While theoretically the resizer can be a drop-in replacement of the default resizer anywhere in the data generation and machine learning pipeline, we mainly demonstrate its ability to learn more informative thumbnail images for downstream recognition and detection tasks, which account for most of the practical use cases. We showcase the impact of MULLER by jointly training it with the backbone, where the resizer takes a higher-resolution image from the data pipeline and downscales it to lower-size before feeding as the model inputs. Since the proposed resizer is strongly regularized by its design, it needs no extra intermediate loss to train. The resizer is also task agnostic as no specific changes are needed to train with it in any framework on any vision or even vision-language tasks." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.721, + 0.21, + 0.739 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.746, + 0.47, + 0.868 + ], + "angle": 0, + "content": "We validate the performance of our proposed MULLER resizer on several competitive vision tasks on which resolution plays an important role on performance, including image classification, object detection and segmentation, and image quality assessment. In order to showcase the impact of MULLER, our main experiments include the state-of-the-art vision Transformer model MaxViT [50] as the baseline. We first demonstrate the performance of this baseline" + }, + { + "type": "page_footnote", + "bbox": [ + 0.076, + 0.875, + 0.47, + 0.903 + ], + "angle": 0, + "content": "1Note that MULLER is not limited to downscaling, and in fact should the original image data be low resolution, it can learn to upscale as well." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.199 + ], + "angle": 0, + "content": "model by co-training it with MULLER. Then, we show that MULLER can be effective with other backbones such as ResNet [11], MobileNet-v2 [35] and EfficientNet-B0 [46]. In all the experiments, we use 2 layers in MULLER with Gaussian kernel size 5 and standard deviation 1. We use Tensorflow's default resizing as the base resizing. More experimental details can be found in supplementary materials." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.21, + 0.89, + 0.226 + ], + "angle": 0, + "content": "4.1. Main Experiments on ImageNet Classification" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.234, + 0.892, + 0.385 + ], + "angle": 0, + "content": "We demonstrate the efficacy of the MULLER resizer on the standard, but most competitive ImageNet-1K classification task [15]. We take a top-performing vision Transformer, MaxViT [50], as the backbone model, and pre-train it on ImageNet-1K at \\(224 \\times 224\\) resolution for 300 epochs. Instead of directly fine-tuning at higher resolution (e.g., 384 or 512) like previous practices [8,9,24,50], we jointly fine-tune the backbone with the MULLER resizer plugged before the stem layers. We set input and output resolutions as 512 and 224 for MULLER in the ImageNet experiments." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.386, + 0.893, + 0.598 + ], + "angle": 0, + "content": "ImageNet-1K. The main results on ImageNet-1K classification are shown in Tab. 1. Note that we include all the state-of-the-art models trained to their highest possible accuracy reported in the original papers. For better visualization, we draw the accuracy vs. FLOPs and accuracy vs. inference-latency scaling curves in Fig. 3, respectively. As may be seen, MaxViT powered by the MULLER resizer sets a new state-of-the-art top-1 accuracy \\(85.68\\%\\) with only 43.9B FLOPs among all the compared models trained at 224x224. MULLER improves at an average of 0.49 accuracy across the four MaxViT variants. In terms of actual inference time, MaxViT with MULLER exceeds among all the models trained at various resolution - equivalently, it can save \\(36\\%\\) latency to achieve \\(\\sim 85.7\\%\\) accuracy." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.599, + 0.892, + 0.78 + ], + "angle": 0, + "content": "ImageNet-21K and JFT. To demonstrate the scaling properties of the MULLER resizer with respect to data size, in Tab. 2 we report the results of the models pre-trained on ImageNet-21K and JFT-300M [38], respectively. It can be seen that with ImageNet-21k pretraining, the finetuned MaxViT with MULLER\\(_{512 \\rightarrow 224}\\) gains \\(0.8\\%\\), \\(0.6\\%\\), and \\(0.7\\%\\) accuracy over directly finetuning without resizer for B, L, and XL models, respectively. Similarly for JFT-300M pretraining, those numbers are \\(0.8\\%\\), \\(0.7\\%\\), and \\(0.7\\%\\). It indicates that when finetuning with MULLER, MaxViT scales consistently when data size increases from ImageNet-1k up to JFT-300M." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.781, + 0.892, + 0.902 + ], + "angle": 0, + "content": "We further observe that for larger models and larger training sets, the backbone can benefit even more through seeing larger input images. Thus, we also report the performance of training with \\( \\mathrm{MULLER}_{576\\rightarrow 288} \\). We can see that it further boosts the performance by an average of \\( 0.4\\sim 0.5\\% \\) across the board for both 21K and JFT. Remarkably, MaxViT-XL with \\( \\mathrm{MULLER}_{576\\rightarrow 288} \\) achieves \\( 89.16\\% \\) top-1 accuracy with only 162.9B FLOPs." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "6880" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.079, + 0.089, + 0.473, + 0.52 + ], + "angle": 0, + "content": "
ModelEval sizeParamsFLOPsThr (img/s)IN-1K top-1 acc
EffNetV2-S [47]38424M8.8B666.683.9
EffNetV2-M [47]48055M24.0B280.785.1
ConvNeXt-T [25]22429M4.5B77482.1
ConvNeXt-S [25]22450M8.7B447.183.1
ConvNeXt-B [25]22489M15.4B292.183.8
ConvNeXt-L [25]224198M34.4B146.884.3
ViT-B/32 [9]38486M55.4B85.977.9
ViT-B/16 [9]384307M190.7B27.376.5
Swin-T [24]22429M4.5B755.281.3
Swin-S [24]22450M8.7B436.983.0
Swin-B [24]22488M15.4B278.183.5
CSwin-B [8]22423M4.3B70182.7
CSwin-B [8]22435M6.9B43783.6
CSwin-B [8]22478M15.0B25084.2
CoAtNet-0 [7]22425M4.2B52681.6
CoAtNet-1 [7]22425M4.2B33683.3
CoAtNet-2 [7]22475M15.7B247.784.1
CoAtNet-3 [7]224168M34.7B163.384.5
MaxViT-T22431M5.6B350.483.62
+MULLER512→22422431M5.63B349.683.95
MaxViT-S22469M11.7B242.584.45
+MULLER512→22422469M11.73B241.484.95
MaxViT-B224120M23.4B133.684.95
+MULLER512→224224120M23.43B133.085.58
MaxViT-L224212M43.9B99.485.17
+MULLER512→224224212M43.93B99.385.68
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.53, + 0.47, + 0.637 + ], + "angle": 0, + "content": "Table 1. Performance comparison under the ImageNet-1K setting. MULLER\\(_{\\mathrm{A} \\rightarrow \\mathrm{B}}\\) denote that MULLER resizes from A to B, where the backbone takes images of size B. FLOPs counts the total computation of the resolver and backbone. Throughput (Thr) is measured on a single V100 GPU with batch size 16, following [24,25,47]. \\(\\bullet\\), \\(\\diamond\\), and \\(\\diamond\\) denote ConvNets, Transformers, and hybrid models, respectively." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.654, + 0.47, + 0.759 + ], + "angle": 0, + "content": "We also examine the generalization of the resizer across different model variants. We found that the learned weights in MULLER are very close across different variants, and the transferring results are as effective as the original training. Detailed results are in the supplementary materials. Note that we present our generalization experiments across different backbones in the next section." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.771, + 0.273, + 0.787 + ], + "angle": 0, + "content": "4.2. Different Backbones" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Main results. To explore the resizer beyond the MaxViT architecture, we selected some widely used backbones including ResNet-50 [11], EfficientNet-B0 [46], and MobileNetv2 [35]. Our results are presented in Tab. 3. We also make comparisons with the resizer of Talebi et al. [45]. We observed that the proposed resizer improves the performance of the baseline backbones consistently. Also compared to" + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.093, + 0.885, + 0.308 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.509, + 0.314, + 0.887, + 0.533 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.545, + 0.895, + 0.683 + ], + "angle": 0, + "content": "Figure 3. Model FLOPs (top), and Inference Latency (bottom) performance comparison of state-of-the-art vision backbones on ImageNet-1K. We show that MaxViT trained with MULLER resizer yielded the best accuracy vs. computation and accuracy vs. inference-cost tradeoff. Note that top figure includes only \\(224 \\times 224\\) models whereas the bottom figures include the best possible performance curves among various training size. Inference time is calculated by the throughput in Tab. 1." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.701, + 0.892, + 0.776 + ], + "angle": 0, + "content": "[46], MULLER requires a significantly lower number of FLOPs (two orders-of-magnitude), and in some cases such as MobileNet-v2 and EfficientNet-B0 it outperforms [45]. These results also indicate that MULLER improves over baseline resizers low the FLOPs regime as well." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.779, + 0.892, + 0.854 + ], + "angle": 0, + "content": "Cross-model Generalization. In order to examine the generalizability of MULLER, we evaluate classification models with resizers that are trained with other backbones. To this end, we first present the learned resizer parameters for each backbone, and then discuss the classification performances." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Results in Tab. 4 represent the learned MULLER parameters (see Eq. 2) for each backbone model trained on ImageNet-1k. We observed that (1) performance of the clas" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.956 + ], + "angle": 0, + "content": "6881" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.078, + 0.088, + 0.473, + 0.598 + ], + "angle": 0, + "content": "
ModelEval sizeParamsFLOPsIN-1K top-1 acc.
21K-ptJFT-pt
BiT-R-101x3 [14]384388M204.6B84.4-
BiT-R-152x4 [14]480937M840.5B85.4-
EffNetV2-L [47]480121M53.0B86.8-
EffNetV2-XL [47]512208M94.0B87.3-
ConvNeXt-L [25]384198M101.0B87.5-
ConvNeXt-XL [25]384350M179.0B87.8-
NFNet-F4+ [2]512527M367B-89.20
ViT-B/16 [9]38487M55.5B84.0-
ViT-L/16 [9]384305M191.1B85.2
ViT-L/16 [9]512305M364B-87.76
ViT-H/14 [9]518632M1021B-88.55
HaloNet-H4 [52]51285M-85.8-
SwinV2-B [24]38488M-87.1-
SwinV2-L [24]384197M-87.7-
CvT-W24 [55]384277M193.2B87.7-
R+ViT-L/16 [9]384330M--87.12
CoAtNet-3 [7]384168M107.4B87.688.52
CoAtNet-3 [7]512168M214B87.988.81
CoAtNet-4 [7]512275M360.9B88.189.11
MaxViT-B224119M23.4B86.6387.05
+MULLER512→224224119M23.4B87.4087.82
+MULLER576→288288119M40.6B87.9288.39
MaxViT-L224212M43.9B86.8687.72
+MULLER512→224224212M43.9B87.4888.43
+MULLER576→288288212M73.4B87.9488.87
MaxViT-XL224475M97.8B87.2588.06
+MULLER512→224224475M97.8B87.9088.74
+MULLER576→288288475M162.9B88.3189.16
MaxViT-B512119M138.3B88.3888.82
MaxViT-L512212M245.2B88.4689.41
MaxViT-XL512475M535.2B88.7089.53
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.607, + 0.47, + 0.699 + ], + "angle": 0, + "content": "Table 2. Performance comparison for large-scale data regimes: ImageNet-21K and JFT pretrained models. We report results using two different settings: \\( \\mathrm{MULLER}_{512\\rightarrow 224} \\) and \\( \\mathrm{MULLER}_{576\\rightarrow 288} \\) respectively, as we observe that on larger models and larger training sets, the backbone benefits more by seeing larger inputs." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.717, + 0.469, + 0.809 + ], + "angle": 0, + "content": "sification models are more sensitive to \\(\\alpha_{1}\\) than \\(\\alpha_{2}\\), and (2) the learned bias values are relatively small, meaning the resizer does not significantly shift the mean of each residual image layer. Note that \\(|\\alpha_{\\ell}| > 1\\) means the image details represented by the \\(\\ell\\)-th layer are boosted, whereas \\(|\\alpha_{\\ell}| < 1\\) has the opposite effect." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.47, + 0.902 + ], + "angle": 0, + "content": "To quantify generalizability of the resizer, we used the learned parameters in Tab. 4 to evaluate different backbones. As for different backbones, Tab. 5 shows that one model leads to classification performance that is in the average proximity of 0.15 from the best top-1 accuracy. We believe this can be explained by the fact that MULLER is a" + }, + { + "type": "table", + "bbox": [ + 0.536, + 0.088, + 0.86, + 0.248 + ], + "angle": 0, + "content": "
ModelSizeFLOPstop-1 acc.
EffNet-B0 [46]2240.39B77.1
+ [45]512→2242242.63B77.9
+MULLER512→2242240.42B78.2
MobileNet-v2 [35]2240.60B70.5
+ [45]512→2242242.84B71.5
+MULLER512→2242240.63B71.8
ResNet-50 [11]2246.97B75.3
+ [45]512→2242249.33B76.2
+MULLER512→2242247.0B76.2
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.257, + 0.892, + 0.289 + ], + "angle": 0, + "content": "Table 3. Performance comparison under ImageNet-1K setting with different backbones." + }, + { + "type": "table", + "bbox": [ + 0.515, + 0.302, + 0.88, + 0.371 + ], + "angle": 0, + "content": "
Modelα1β1α2β2
EffNet-B0 [46]1.7150.088-8.410.001
MobileNet-v2 [35]1.4800.174-5.25-0.058
ResNet-50 [11]1.892-0.014-11.2950.003
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.381, + 0.892, + 0.412 + ], + "angle": 0, + "content": "Table 4. The learned MULLER parameters for different backbone models train on ImageNet-1k." + }, + { + "type": "table", + "bbox": [ + 0.507, + 0.426, + 0.888, + 0.495 + ], + "angle": 0, + "content": "
ModelEffNet-B0MobileNet-v2ResNet-50
MULLEREffNet78.271.675.9
MULLERMobileNet78.071.876.0
MULLERResNet78.171.776.2
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.504, + 0.892, + 0.534 + ], + "angle": 0, + "content": "Table 5. Cross-model validation of the MULLER resolver for ImageNet-1K on different backbones." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.551, + 0.892, + 0.596 + ], + "angle": 0, + "content": "constrained model with only 4 trainable parameters. Also, it is important to highlight that in contrast to the resizer in [45], MULLER does not require fine-tuning." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.596, + 0.893, + 0.747 + ], + "angle": 0, + "content": "Impact of Aliasing. It has been shown that aliasing may impact the performance of some deep vision models [29,51]. It is worth mentioning that the results presented in this section are based on anti-aliased images. More specifically, we used the AREA downscaling method in TensorFlow to produce \\(512^{2}\\) inputs to MULLER. We observed that while removing anti-aliasing does not hamper the overall performance gain obtained by MULLER, the learned parameters may differ from Tab. 4. We will present our results without anti-aliasing in the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.757, + 0.679, + 0.771 + ], + "angle": 0, + "content": "4.3. Downstream tasks" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.892, + 0.885 + ], + "angle": 0, + "content": "Object Detection and Instance Segmentation. We evaluated the performance of MULLER on COCO2017 [21] for object bounding box detection and instance segmentation tasks with a two-stage cascaded Mask-RCNN framework [31]. We warm start the MaxViT backbone using checkpoints pretrained on ImageNet-1K, then finetune the whole model including the resizing on COCO." + }, + { + "type": "text", + "bbox": [ + 0.52, + 0.887, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Tab. 6 summarizes the object detection and instance seg" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6882" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.078, + 0.089, + 0.473, + 0.414 + ], + "angle": 0, + "content": "
BackboneResolutionAP\\( AP_{50} \\)\\( AP_{75} \\)\\( AP^m \\)\\( AP_{50}^m \\)\\( AP_{75}^m \\)FLOPs
•ResNet-50 [11]1280×80046.364.350.540.161.743.4739B
•X101-32 [56]1280×80048.166.552.441.663.945.2819B
•X101-64 [56]1280×80048.366.452.341.764.045.1972B
•ConvNeXt-T [25]1280×80050.469.154.843.766.547.3741B
•ConvNeXt-S [25]1280×80051.970.856.545.068.449.1827B
•ConvNeXt-B [25]1280×80052.771.357.245.668.949.5964B
○Swin-T [24]1280×80050.469.254.743.766.647.3745B
○Swin-S [24]1280×80051.970.756.345.068.248.8838B
○Swin-B [24]1280×80051.970.556.445.068.148.9982B
○UViT-T [6]896×89651.170.456.243.667.747.2613B
○UViT-S [6]896×89651.470.856.244.168.248.0744B
○UViT-B [6]896×89652.572.057.644.368.748.3975B
○MaxViT-T640×64049.969.954.642.766.646.4379B
○+MULR896→640640×64050.570.755.043.167.046.7379B
○MaxViT-S640×64050.570.255.343.367.346.8432B
○+MULR896→640640×64050.870.455.543.567.747.1432B
○MaxViT-B640×64051.671.356.144.168.547.7543B
○+MULR896→640640×64052.371.557.044.768.948.7543B
○MaxViT-T896×89652.171.956.844.669.148.4475B
○MaxViT-S896×89653.172.558.145.469.849.5595B
○MaxViT-B896×89653.472.958.145.770.350.0856B
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.423, + 0.471, + 0.469 + ], + "angle": 0, + "content": "Table 6. Comparison of two-stage object detection and instance segmentation on COCO2017. All models are pretrained on ImageNet-1K." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.502, + 0.47, + 0.669 + ], + "angle": 0, + "content": "mentation results comparing state-of-the-art ConvNets and vision Transformers. AP and \\(\\mathrm{AP}^m\\) denote box and mask average precision. We report the train and evaluation resolutions as well as their corresponding FLOPs as reference for model complexity. It may be seen that MaxViT suffers from noticeable performance drop if training resolution is lower. However, we observed that training with the MULLER resized can further improve the performance across the board. Specifically, on MaxViT-B at \\(640 \\times 640\\), finetuning with MULLER gains 0.7 AP and 0.6 mask AP on the COCO validation set without any FLOPs overhead." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.671, + 0.47, + 0.809 + ], + "angle": 0, + "content": "Image Quality Assessment. We base our experiment on the AVA dataset [28], which includes 250K images rated by amateur photographers. Each image in the dataset is associated with a histogram of ratings from an average of 200 raters. Image quality and aesthetic assessment is a task that is sensitive to downscaling [13], as downscaling may negatively impact visual quality attributes such as sharpness. We use the Earth Mover's Distance (EMD) as our training loss, similar to previous work of [44]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Our results are shown in Tab. 7. We report the Pearson linear correlation coefficient (PLCC) of the predicted and ground truth mean ratings as our evaluation metric. As can be seen, the proposed resizer improves the performance of MaxViT beyond the existing methods such as MUSIQ [13]. Note that in contrast to MUSIQ which uses multi-scale in" + }, + { + "type": "table", + "bbox": [ + 0.541, + 0.089, + 0.857, + 0.265 + ], + "angle": 0, + "content": "
ModelSizeParamsPLCC↑
•NIMA [44]22456M0.636
•+ [45]512→22422456M0.680
•EffNet-B0 [46]2245.3M0.642
•+ [45]512→2242245.3M0.650
•AFDC [5]22444.5M0.671
○ViT-S/32 [13]38422M0.665
○ViT-B/32 [13]38488M0.664
○MUSIQ [13]224~51227M0.720
◇MaxViT-T22431M0.707
◇+MULLER512→22422431M0.729
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.273, + 0.892, + 0.318 + ], + "angle": 0, + "content": "Table 7. Image aesthetic assessment results on the AVA benchmark [28]. PLCC represents the Pearson's linear correlation coefficient." + }, + { + "type": "table", + "bbox": [ + 0.537, + 0.334, + 0.859, + 0.479 + ], + "angle": 0, + "content": "
nlayersksizestdTop-1 AccFLOPs
251.085.5824.23B
351.085.5224.24B
451.085.5024.25B
651.085.5924.27B
231.085.4824.23B
271.085.5724.24B
251.585.5624.24B
252.085.5324.24B
" + }, + { + "type": "table_caption", + "bbox": [ + 0.531, + 0.489, + 0.862, + 0.505 + ], + "angle": 0, + "content": "Table 8. Hyperparameter sweep for MULLER." + }, + { + "type": "table", + "bbox": [ + 0.526, + 0.519, + 0.868, + 0.648 + ], + "angle": 0, + "content": "
input sizeoutput sizeTop-1 AccFLOPs
38422485.4524.22B
51222485.5824.23B
76822485.5624.26B
51238486.4274.25B
76838486.4474.28B
76851286.68138.57B
102451286.67138.60B
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.658, + 0.892, + 0.704 + ], + "angle": 0, + "content": "Table 9. Effects of input and output size for MULLER using MaxViT-Base as test backkBone. Note that the output size is the image size seen by the backbone." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.731, + 0.892, + 0.763 + ], + "angle": 0, + "content": "put augmentations, MULLER+MaxViT only requires a single low-resolution input from the resizing." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.772, + 0.605, + 0.787 + ], + "angle": 0, + "content": "4.4. Ablation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Hyperparameters. There are three hyperparameters in the design of MULLER: \\(\\{k, hsize, stddev\\}\\), which denote the number of layers, the kernel size of the Gaussian filters \\(\\{\\mathbf{W}_1, \\mathbf{W}_2, \\dots, \\mathbf{W}_k\\}\\), and the standard deviation of the Gaussian filters. To understand the effect of these hyperparameters, we conduct an ablation study. As shown in Tab. 8, we found that MULLER is quite insensitive to the selection" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6883" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.109, + 0.089, + 0.331, + 0.223 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.109, + 0.223, + 0.332, + 0.356 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.179, + 0.357, + 0.25, + 0.37 + ], + "angle": 0, + "content": "(a) Original" + }, + { + "type": "image", + "bbox": [ + 0.335, + 0.089, + 0.508, + 0.222 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.335, + 0.223, + 0.508, + 0.356 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.371, + 0.357, + 0.482, + 0.369 + ], + "angle": 0, + "content": "(b) Default resizer" + }, + { + "type": "image", + "bbox": [ + 0.51, + 0.089, + 0.683, + 0.222 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.51, + 0.223, + 0.683, + 0.356 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.54, + 0.357, + 0.654, + 0.369 + ], + "angle": 0, + "content": "(c) Learned resizer" + }, + { + "type": "image", + "bbox": [ + 0.685, + 0.089, + 0.858, + 0.222 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.685, + 0.223, + 0.858, + 0.356 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.729, + 0.357, + 0.816, + 0.369 + ], + "angle": 0, + "content": "(d) Difference" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.373, + 0.892, + 0.404 + ], + "angle": 0, + "content": "Figure 4. Visualizations of the learned MULLER resizer for ResNet-50. Here the default resizer is an (anti-aliased) AREA resizer in Tensorflow. (d) shows the difference of the learned and the default resizers." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.424, + 0.47, + 0.455 + ], + "angle": 0, + "content": "of parameters, and thus we recommend to use a simple set of parameters to save computation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.458, + 0.471, + 0.653 + ], + "angle": 0, + "content": "Effects of image size. It is known that image size can significantly affect the recognition performance. We evaluate the effect of varying input and output sizes of MULLER using MaxViT-B in Tab. 9. Note that the output size of MULLER is indeed the size seen by the backbone, so higher output size typically corresponds to improved accuracy. We observe that using higher input resolutions (e.g., \\(3 \\times\\)) for MULLER does not yield any further performance gain beyond the baseline setting. Nonetheless, we find that adopting a reasonably large resolution (e.g. \\(1.6 \\sim 2.5 \\times\\)) is necessary to achieve the expected performance. It is worth highlighting that this is perhaps impacted by the original resolution of images in the benchmark dataset." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.677, + 0.214, + 0.691 + ], + "angle": 0, + "content": "4.5. Visualization" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.704, + 0.47, + 0.901 + ], + "angle": 0, + "content": "We visualize the behavior of the learned resizer in Fig. 4. As can be seen, the MULLER resizer is learned to boost details or textures of the images, while also enhancing the image contrast. These effects can preserve more visual information in the downscaled images over naive resizing, thus making the classification model learn better. As compared to the previous less-controlled resizer [45], MULLER achieves a better balance of human and machine perceptual qualities, due to the strong regularization imbued in its Laplacian-inspired design. We also point out that training MULLER with aliased inputs may produce relatively less sharper images in comparison to Fig. 4. We refer the reader to the supplementary material for visual examples." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.422, + 0.704, + 0.44 + ], + "angle": 0, + "content": "5. Concluding Remarks" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.448, + 0.892, + 0.78 + ], + "angle": 0, + "content": "In this paper, we introduce MULLER, an extremely simple and light learned resizer, using multilayer Laplacian decomposition. The proposed resizer only contains 4 trainable parameters with negligible training and inference costs. This allows deploying the resizer as a thumbnail generator to produce optimally downscaled images for sending to remote inference servers, or alternatively as a server side resizer that reduces the inference cost without the necessity of changing the backbone architecture. We show that MULLER not only pushes forward the limit of the state-of-the-art vision Transformer MaxViT on ImageNet classification, but it also consistently improves across a range of widely used architectures, including EfficientNet, MobileNet, and ResNet. Additionally, we provide experiments to substantiate the efficacy of MULLER for various downstream tasks, such as object detection, segmentation, and image quality assessment. As compared to previous methods, MULLER enjoys remarkable generalization ability, owing to the strong regularization provided by its multilayer bandpass design. We believe that our work will inspire future research in this critically important direction: how to better preprocess images for vision tasks." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Limitations and future works. We note that if the higher-resolution inputs fail to boost the performance of an specific task, we cannot reasonably expect the learned resizer to provide a substantial performance boost either. Another potential future direction is to train a universal learned resizer that can be a drop-in replacement of the off-the-shelf resizers in existing machine learning frameworks, without necessitating the joint re-training of the backbones." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "6884" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.115, + 0.47, + 0.184 + ], + "angle": 0, + "content": "[1] Martín Abadi, Ashish Agarwal, Paul Barham, Eugene Brevdo, Zhifeng Chen, Craig Citro, Greg S Corrado, Andy Davis, Jeffrey Dean, Matthieu Devin, et al. Tensorflow: Large-scale machine learning on heterogeneous distributed systems. arXiv preprint arXiv:1603.04467, 2016. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.186, + 0.472, + 0.24 + ], + "angle": 0, + "content": "[2] Andy Brock, Soham De, Samuel L Smith, and Karen Simonyan. High-performance large-scale image recognition without normalization. In International Conference on Machine Learning, pages 1059-1071. PMLR, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.242, + 0.471, + 0.297 + ], + "angle": 0, + "content": "[3] Li-Heng Chen, Christos G Bampis, Zhi Li, Lukáš Krasula, and Alan C Bovik. Estimating the resize parameter in end-to-end learned image compression. arXiv preprint arXiv:2204.12022, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.298, + 0.471, + 0.354 + ], + "angle": 0, + "content": "[4] Li-Heng Chen, Christos G Bampis, Zhi Li, Joel Sole, and Alan C Bovik. A progressive architecture for learned fractional downsampling. In 2021 Picture Coding Symposium (PCS), pages 1-5. IEEE, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.355, + 0.471, + 0.424 + ], + "angle": 0, + "content": "[5] Qiuyu Chen, Wei Zhang, Ning Zhou, Peng Lei, Yi Xu, Yu Zheng, and Jianping Fan. Adaptive fractional dilated convolution network for image aesthetics assessment. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14114-14123, 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.425, + 0.471, + 0.493 + ], + "angle": 0, + "content": "[6] Wuyang Chen, Xianzhi Du, Fan Yang, Lucas Beyer, Xiaohua Zhai, Tsung-Yi Lin, Huizhong Chen, Jing Li, Xiaodan Song, Zhangyang Wang, and Denny Zhou. A simple single-scale vision transformer for object localization and instance segmentation. CoRR, abs/2112.09747, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.495, + 0.471, + 0.549 + ], + "angle": 0, + "content": "[7] Zihang Dai, Hanxiao Liu, Quoc Le, and Mingxing Tan. Coatnet: Marrying convolution and attention for all data sizes. Advances in Neural Information Processing Systems, 34, 2021. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.551, + 0.471, + 0.62 + ], + "angle": 0, + "content": "[8] Xiaoyi Dong, Jianmin Bao, Dongdong Chen, Weiming Zhang, Nenghai Yu, Lu Yuan, Dong Chen, and Baining Guo. Cswin transformer: A general vision transformer backbone with cross-shaped windows. arXiv preprint arXiv:2107.00652, 2021. 4, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.621, + 0.471, + 0.704 + ], + "angle": 0, + "content": "[9] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020.4,5,6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.705, + 0.47, + 0.789 + ], + "angle": 0, + "content": "[10] Muhammad Haris, Greg Shakhnarovich, and Norimichi Ukita. Task-driven super resolution: Object detection in low-resolution images. In Neural Information Processing: 28th International Conference, ICONIP 2021, Sanur, Bali, Indonesia, December 8-12, 2021, Proceedings, Part V 28, pages 387-395. Springer, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.79, + 0.47, + 0.845 + ], + "angle": 0, + "content": "[11] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 1, 4, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[12] Gao Huang, Zhuang Liu, Laurens Van Der Maaten, and Kilian Q Weinberger. Densely connected convolutional networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4700-4708, 2017. 1" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.115, + 0.472, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.148 + ], + "angle": 0, + "content": "[13] Junjie Ke, Qifei Wang, Yilin Wang, Peyman Milanfar, and Feng Yang. Musiq: Multi-scale image quality transformer. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 5148-5157, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.149, + 0.892, + 0.218 + ], + "angle": 0, + "content": "[14] Alexander Kolesnikov, Lucas Beyer, Xiaohua Zhai, Joan Puigcerver, Jessica Yung, Sylvain Gelly, and Neil Houlsby. Big transfer (bit): General visual representation learning. In European conference on computer vision, pages 491-507. Springer, 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.219, + 0.892, + 0.272 + ], + "angle": 0, + "content": "[15] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E Hinton. Imagenet classification with deep convolutional neural networks. Advances in neural information processing systems, 25, 2012. 1, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.274, + 0.892, + 0.328 + ], + "angle": 0, + "content": "[16] Boyi Li, Xiulian Peng, Zhangyang Wang, Jizheng Xu, and Dan Feng. End-to-end united video dehazing and detection. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 32, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.33, + 0.892, + 0.385 + ], + "angle": 0, + "content": "[17] Boyi Li, Wenqi Ren, Dengpan Fu, Dacheng Tao, Dan Feng, Wenjun Zeng, and Zhangyang Wang. Benchmarking single-image dehazing and beyond. IEEE Transactions on Image Processing, 28(1):492-505, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.386, + 0.892, + 0.469 + ], + "angle": 0, + "content": "[18] Siyuan Li, Iago Bruno Araujo, Wenqi Ren, Zhangyang Wang, Eric K Tokuda, Roberto Hirata Junior, Roberto Cesar-Junior, Jiawan Zhang, Xiaojie Guo, and Xiaochun Cao. Single image deraining: A comprehensive benchmark analysis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3838-3847, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.47, + 0.892, + 0.538 + ], + "angle": 0, + "content": "[19] Yinxiao Li, Pengchong Jin, Feng Yang, Ce Liu, Ming-Hsuan Yang, and Peyman Milanfar. Comisr: Compression-informed video super-resolution. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2543-2552, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.539, + 0.892, + 0.594 + ], + "angle": 0, + "content": "[20] Yue Li, Dong Liu, Houqiang Li, Li Li, Zhu Li, and Feng Wu. Learning a convolutional neural network for image compact-resolution. IEEE Transactions on Image Processing, 28(3):1092-1107, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.595, + 0.892, + 0.663 + ], + "angle": 0, + "content": "[21] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In European conference on computer vision, pages 740-755. Springer, 2014. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.665, + 0.892, + 0.718 + ], + "angle": 0, + "content": "[22] Ding Liu, Bihan Wen, Xianming Liu, Zhangyang Wang, and Thomas S Huang. When image denoising meets high-level vision tasks: A deep learning approach. arXiv preprint arXiv:1706.04284, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.72, + 0.895, + 0.789 + ], + "angle": 0, + "content": "[23] Feng Liu, Ronghang Zhu, Dan Zeng, Qijun Zhao, and Xiaoming Liu. Disentangling features in 3d face shapes for joint face reconstruction and recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5216-5225, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.79, + 0.892, + 0.859 + ], + "angle": 0, + "content": "[24] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10012-10022, 2021. 1, 4, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.86, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[25] Zhuang Liu, Hanzi Mao, Chao-Yuan Wu, Christoph Feichtenhofer, Trevor Darrell, and Saining Xie. A convnet for the 2020s. arXiv preprint arXiv:2201.03545, 2022. 5, 6, 7" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.895, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.515, + 0.957 + ], + "angle": 0, + "content": "6885" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[26] Zhuang Liu, Tinghui Zhou, Hung-Ju Wang, Zhiqiang Shen, Bingyi Kang, Evan Shelhamer, and Trevor Darrell. Transferable recognition-aware image processing. arXiv preprint arXiv:1910.09185, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.149, + 0.47, + 0.19 + ], + "angle": 0, + "content": "[27] Peyman Milanfar. A tour of modern image filtering: New insights and methods, both practical and theoretical. IEEE signal processing magazine, 30(1):106-128, 2012. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.191, + 0.469, + 0.245 + ], + "angle": 0, + "content": "[28] Naila Murray, Luca Marchesotti, and Florent Perronnin. Ava: A large-scale database for aesthetic visual analysis. In 2012 IEEE conference on computer vision and pattern recognition, pages 2408-2415. IEEE, 2012. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.247, + 0.469, + 0.287 + ], + "angle": 0, + "content": "[29] Gaurav Parmar, Richard Zhang, and Jun-Yan Zhu. On buggy resizing libraries and surprising subtleties in fid calculation. arXiv preprint arXiv:2104.11222, 2021. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.289, + 0.469, + 0.369 + ], + "angle": 0, + "content": "[30] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, Luca Antiga, et al. Pytorch: An imperative style, high-performance deep learning library. Advances in neural information processing systems, 32, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.372, + 0.469, + 0.453 + ], + "angle": 0, + "content": "[31] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. In C. Cortes, N. Lawrence, D. Lee, M. Sugiyama, and R. Garnett, editors, Advances in Neural Information Processing Systems, volume 28. Curran Associates, Inc., 2015. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.455, + 0.469, + 0.496 + ], + "angle": 0, + "content": "[32] Rachid Riad, Olivier Teboul, David Grangier, and Neil Zeghidour. Learning strides in convolutional neural networks. arXiv preprint arXiv:2202.01653, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.498, + 0.469, + 0.564 + ], + "angle": 0, + "content": "[33] Avinab Saha, Sandeep Mishra, and Alan C Bovik. Reiaq: Unsupervised learning for image quality assessment in the wild. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5846-5855, 2023. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.567, + 0.469, + 0.621 + ], + "angle": 0, + "content": "[34] Mehdi SM Sajjadi, Bernhard Scholkopf, and Michael Hirsch. Enhancenet: Single image super-resolution through automated texture synthesis. arXiv preprint arXiv:1612.07919, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.623, + 0.469, + 0.691 + ], + "angle": 0, + "content": "[35] Mark Sandler, Andrew Howard, Menglong Zhu, Andrey Zh-moginov, and Liang-Chieh Chen. Mobilenetv2: Inverted residuals and linear bottlenecks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4510-4520, 2018. 1, 4, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.693, + 0.469, + 0.761 + ], + "angle": 0, + "content": "[36] Vivek Sharma, Ali Diba, Davy Neven, Michael S Brown, Luc Van Gool, and Rainer Stiefelhagen. Classification-driven dynamic image enhancement. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4033-4041, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.763, + 0.469, + 0.844 + ], + "angle": 0, + "content": "[37] Wenzhe Shi, Jose Caballero, Ferenc Huszár, Johannes Totz, Andrew P Aitken, Rob Bishop, Daniel Rueckert, and Zehan Wang. Real-time single image and video super-resolution using an efficient sub-pixel convolutional neural network. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1874-1883, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.846, + 0.469, + 0.9 + ], + "angle": 0, + "content": "[38] Chen Sun, Abhinav Shrivastava, Saurabh Singh, and Abhinav Gupta. Revisiting unreasonable effectiveness of data in deep learning era. In Proceedings of the IEEE international conference on computer vision, pages 843-852, 2017. 4" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.16 + ], + "angle": 0, + "content": "[39] Satoshi Suzuki, Motohiro Takagi, Kazuya Hayase, Takayuki Onishi, and Atsushi Shimizu. Image pre-transformation for recognition-aware image compression. In 2019 IEEE International Conference on Image Processing (ICIP), pages 2686-2690. IEEE, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.163, + 0.892, + 0.243 + ], + "angle": 0, + "content": "[40] Christian Szegedy, Wei Liu, Yangqing Jia, Pierre Sermanet, Scott Reed, Dragomir Anguelov, Dumitru Erhan, Vincent Vanhoucke, and Andrew Rabinovich. Going deeper with convolutions. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1-9, 2015. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.246, + 0.892, + 0.313 + ], + "angle": 0, + "content": "[41] Christian Szegedy, Vincent Vanhoucke, Sergey Ioffe, Jon Shlens, and Zbigniew Wojna. Rethinking the inception architecture for computer vision. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2818-2826, 2016. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.316, + 0.892, + 0.371 + ], + "angle": 0, + "content": "[42] Hossein Talebi, Damien Kelly, Xiyang Luo, Ignacio Garcia Dorado, Feng Yang, Peyman Milanfar, and Michael Elad. Better compression with deep pre-editing. IEEE Transactions on Image Processing, 30:6673-6685, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.372, + 0.892, + 0.412 + ], + "angle": 0, + "content": "[43] Hossein Talebi and Peyman Milanfar. Fast multilayer laplacian enhancement. IEEE Transactions on Computational Imaging, 2(4):496-509, 2016. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.414, + 0.892, + 0.453 + ], + "angle": 0, + "content": "[44] Hossein Talebi and Peyman Milanfar. Nima: Neural image assessment. IEEE transactions on image processing, 27(8):3998-4011, 2018. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.456, + 0.892, + 0.509 + ], + "angle": 0, + "content": "[45] Hossein Talebi and Peyman Milanfar. Learning to resize images for computer vision tasks. In Proceedings of the IEEE/CVF international conference on computer vision, pages 497-506, 2021. 2, 3, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.511, + 0.892, + 0.565 + ], + "angle": 0, + "content": "[46] Mingxing Tan and Quoc Le. Efficientnet: Rethinking model scaling for convolutional neural networks. In International conference on machine learning, pages 6105-6114. PMLR, 2019. 1, 4, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.567, + 0.892, + 0.607 + ], + "angle": 0, + "content": "[47] Mingxing Tan and Quoc Le. Efficientnetv2: Smaller models and faster training. In International Conference on Machine Learning, pages 10096-10106. PMLR, 2021. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.609, + 0.892, + 0.663 + ], + "angle": 0, + "content": "[48] Xin Tao, Hongyun Gao, Xiaoyong Shen, Jue Wang, and Jiaya Jia. Scale-recurrent network for deep image deblurring. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 8174-8182, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.665, + 0.892, + 0.718 + ], + "angle": 0, + "content": "[49] Zhengzhong Tu, Hossein Talebi, Han Zhang, Feng Yang, Peyman Milanfar, Alan Bovik, and Yinxiao Li. Maxim: Multi-axis mlp for image processing. arXiv preprint arXiv:2201.02973, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.72, + 0.892, + 0.802 + ], + "angle": 0, + "content": "[50] Zhengzhong Tu, Hossein Talebi, Han Zhang, Feng Yang, Peyman Milanfar, Alan Bovik, and Yinxiao Li. Maxvit: Multi-axis vision transformer. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXIV, pages 459-479. Springer, 2022. 1, 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.804, + 0.892, + 0.872 + ], + "angle": 0, + "content": "[51] Cristina Vasconcelos, Hugo Larochelle, Vincent Dumoulin, Rob Romijnders, Nicolas Le Roux, and Ross Goroshin. Impact of aliasing on generalization in deep convolutional networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10529-10538, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.874, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[52] Ashish Vaswani, Prajit Ramachandran, Aravind Srinivas, Niki Parmar, Blake Hechtman, and Jonathon Shlens. Scaling" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.956 + ], + "angle": 0, + "content": "6886" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.47, + 0.146 + ], + "angle": 0, + "content": "local self-attention for parameter efficient visual backbones. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12894–12904, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.149, + 0.47, + 0.205 + ], + "angle": 0, + "content": "[53] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.207, + 0.47, + 0.248 + ], + "angle": 0, + "content": "[54] Zhou Wang. Image quality assessment: from error visibility to structural similarity. IEEE transactions on image processing, 13(4):600-612, 2004. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.249, + 0.47, + 0.319 + ], + "angle": 0, + "content": "[55] Haiping Wu, Bin Xiao, Noel Codella, Mengchen Liu, Xiyang Dai, Lu Yuan, and Lei Zhang. Cvt: Introducing convolutions to vision transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 22-31, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.32, + 0.47, + 0.387 + ], + "angle": 0, + "content": "[56] Saining Xie, Ross Girshick, Piotr Dólár, Zhuowen Tu, and Kaiming He. Aggregated residual transformations for deep neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1492-1500, 2017. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.39, + 0.47, + 0.432 + ], + "angle": 0, + "content": "[57] Runsheng Xu, Jinlong Li, Xiaoyu Dong, Hongkai Yu, and Jiaqi Ma. Bridging the domain gap for multi-agent perception. arXiv preprint arXiv:2210.08451, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.433, + 0.47, + 0.515 + ], + "angle": 0, + "content": "[58] Runsheng Xu, Hao Xiang, Zhengzhong Tu, Xin Xia, Ming-Hsuan Yang, and Jiaqi Ma. V2x-vit: Vehicle-to-everything cooperative perception with vision transformer. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXXIX, pages 107-124. Springer, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.517, + 0.47, + 0.572 + ], + "angle": 0, + "content": "[59] Kai Zhang, Wangmeng Zuo, Yunjin Chen, Deyu Meng, and Lei Zhang. Beyond a gaussian denoiser: Residual learning of deep cnn for image denoising. IEEE transactions on image processing, 26(7):3142-3155, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.574, + 0.47, + 0.643 + ], + "angle": 0, + "content": "[60] Richard Zhang, Phillip Isola, and Alexei A Efros. Colorful image colorization. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part III 14, pages 649-666. Springer, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.645, + 0.47, + 0.699 + ], + "angle": 0, + "content": "[61] Chen Zhao and Bernard Ghanem. Thumbnet: One thumbnail image contains all you need for recognition. In Proceedings of the 28th ACM International Conference on Multimedia, pages 1506-1514, 2020. 2" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.699 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "6887" + } + ] +] \ No newline at end of file diff --git a/2023/MULLER_ Multilayer Laplacian Resizer for Vision/540b48e0-0e9c-4eba-a984-866547201e9c_origin.pdf b/2023/MULLER_ Multilayer Laplacian Resizer for Vision/540b48e0-0e9c-4eba-a984-866547201e9c_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..01ac18901c9d9ca40333d3b5d428dc38f5de977c --- /dev/null +++ b/2023/MULLER_ Multilayer Laplacian Resizer for Vision/540b48e0-0e9c-4eba-a984-866547201e9c_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:19d458c4063d34455fce5e0cab205df80f570758c41bd3b8254c8b7eedfbd03b +size 1262101 diff --git a/2023/MULLER_ Multilayer Laplacian Resizer for Vision/full.md b/2023/MULLER_ Multilayer Laplacian Resizer for Vision/full.md new file mode 100644 index 0000000000000000000000000000000000000000..10ed8db9c01f59fc0a21f0f1eb6ead3169edfa3c --- /dev/null +++ b/2023/MULLER_ Multilayer Laplacian Resizer for Vision/full.md @@ -0,0 +1,289 @@ +# MULLER: Multilayer Laplacian Resizer for Vision + +Zhengzhong Tu, Peyman Milanfar, Hossein Talebi +Google Research + +zhengzhongtu@gmail.com + +# Abstract + +Image resizing operation is a fundamental preprocessing module in modern computer vision. Throughout the deep learning revolution, researchers have overlooked the potential of alternative resizing methods beyond the commonly used resize that are readily available, such as nearest-neighbors, bilinear, and bicubic. The key question of our interest is whether the front-end resize affects the performance of deep vision models? In this paper, we present an extremely lightweight multilayer Laplacian resolver with only a handful of trainable parameters, dubbed MULLER resolver. MULLER has a bandpass nature in that it learns to boost details in certain frequency subbands that benefit the downstream recognition models. We show that MULLER can be easily plugged into various training pipelines, and it effectively boosts the performance of the underlying vision task with little to no extra cost. Specifically, we select a state-of-the-art vision Transformer, MaxViT [50], as the baseline, and show that, if trained with MULLER, MaxViT gains up to $0.6\%$ top-1 accuracy, and meanwhile enjoys $36\%$ inference cost saving to achieve similar top-1 accuracy on ImageNet-1k, as compared to the standard training scheme. Notably, MULLER's performance also scales with model size and training data size such as ImageNet-21k and JFT, and it is widely applicable to multiple vision tasks, including image classification, object detection and segmentation, as well as image quality assessment. The code is available at https://github.com/google-research/google-research/tree/master/muller. + +# 1. Introduction + +Most computer vision problems such as image classification, object detection, video recognition, and image/video generation have seen groundbreaking advancement by deep neural networks-based models that are trained on web-scale, human-curated datasets [11, 12, 15, 15, 24, 33, 35, 40, 41, 46, 53, 58]. In any of the underlining training infrastructures like Tensorflow [1] and PyTorch [30], image resizing + +![](images/3e7a77c8b92bb54410178bb3d56bf75d6fbe88989d82a86de0b20bd59a5fdb9b.jpg) + +![](images/48a77002fff2f276b713f09dc160eb47a9ea71ad26b521b6e741d167fcf0729d.jpg) +Figure 1. Top: our proposed learned resizer can push forward a strong vision Transformer MaxViT [50] by up to $0.6\%$ top-1 accuracy on ImageNet-1K with no extra inference cost. Results for other backbones are shown in Sec. 4.2. Bottom: demonstration of the learned resizer - with detail-boosted input image, the classification accuracy of the exemplar image has improved. + +is an essential preprocessing step which enables efficient gradient-based training of networks with millions of trainable parameters. Moreover, the factor of image size can sometimes significantly impact the performance of various tasks, particularly those requiring high-resolution prediction. Although neural architectures have been revolutionized by CNNs and Transformers, surprisingly limited attention has been paid to the role of image resizing operations. + +Resizing or rescaling refers to the process of changing the resolution of an image, while largely preserving its content for human or machine perception. There are several major reasons for using resizing: (1) The mini-batch gradient-based training scheme requires the same image resolution in a batch, (2) Resizing can help to reduce computational complexity, making it easier and faster to train + +and inference neural networks, (3) Smaller images consume lower memory footprint, enabling stable training of large models like Transformers with larger batch-size, (4) Resizing contributes to improving model generalization and robustness by reducing overfitting to specific image size and scales, making the models more flexible and applicable to real-world scenarios. + +Moreover, resizing is an integral component of remote inference frameworks. Typically, to maintain the bandwidth efficiency of the communication network, before sending an image to the inference server, a thumbnail generator downscales the image to a fixed resolution (e.g. 480p). The thumbnail generator can be located on the client side (e.g. smart phone), or it can be part of a cloud storage system. This means that in most cases the inference server does not have access to the original image. + +Basic resizing functions such as nearest-neighbor or bilinear interpolation have long been the go-to options with little to no deliberate consideration in most training software. While these simple methods offer greater simplicity and efficiency, they are not optimized for specific computer vision tasks and may lead to the loss of important visual features or details, which can, sometimes, result in significant performance degradation [29, 45]. To overcome this limitation, researchers have proposed learned resizers (or downsamplers) [3, 45] that leverage the deep neural networks to learn image resizing directly from data, yielding improved performance on several tasks. However, one of the main challenges with these learned resizers is that they often require a large number of parameters, and high computational overhead during training and inference. Note that this is specifically a bottleneck in remote inference where the resize (a.k.a thumbnail generator) is not in the inference server, and may have limited computational resources to run a heavy neural net resolver. Additionally, less-bounded resizers can sometimes be difficult to transfer to new tasks or datasets due to their excessive model capability. + +In this paper, we introduce an incredibly lightweight learned resizer, which we call MULLER, that operates on multilayer Laplacian decomposition of images (see Fig. 2). Our method requires very few parameters and FLOPs, and does not incur any extra training cost, outperforming existing methods in terms of computational efficiency, parameter efficiency, and transferability. We show that it is the ability-to-learn that makes a better resizer, but not the capacity of the resizer - our MULLER resizer only learns four parameters and is more effective than previous complex ones using deep residual blocks [45]. We also demonstrate that our method can be used as a drop-in replacement for off-the-shelf resizing functions on several vision tasks, including classification, object detection and segmentation, and image quality assessment, resulting in significant performance improvements without any extra cost. As shown in Fig. 1, + +for example, training with the MULLER responder achieves up to $0.6\%$ performance gain, using a state-of-the-art backbone MaxViT [50] as the testbed. Our contributions are: + +- We propose a surprisingly simple and lightweight resolver, that can be used as a drop-in replacement for off-the-shelf resizing functions like bilinear resizing. +- We demonstrate its applications to multiple computer vision tasks, including image classification, object detection and segmentation, and image quality assessment, showing superior performance over existing approaches. +- Extensive ablation studies, analysis, and visualization results are provided to show the robustness and generalization of the proposed resizer for various model scales, benchmarks, and tasks. + +# 2. Related Work + +Resizing in vision. Resizing is a crucial preprocessing step to train deep learning vision models. Due to their simplicity, efficiency and availability, nearest-neighbor and bilinear interpolations are the most widely used resizing methods in both training, inference, and serving. These simple approaches, however, can suffer from detail loss and artifacts, and the degraded image quality might hamper the performance of downstream visual recognition tasks, especially when the resizing factor is large. + +Some recent works have explored to use learning-based methods for image downscaling to enhance the desired content in the resized images from training data [3,4,20,32,45, 61]. For example, the authors of [3,4] proposed a residual CNN module for downscaling, and jointly trained it with an image compression network to generate "compression-friendly" representations. [45] introduced a CNN-based learned resizer for various computer vision tasks, including image classification and image quality assessment. Similarly, the idea of learned rescaling has been applied to other computer vision applications [20, 32, 57, 61], showing improved performance in detection and recognition. + +Image processing for machine vision. Image processing or enhancement problems such as super-resolution [19, 37], denoising [59], and deblurring [48, 49] have been longstanding challenges in computer vision. Recent works have focused on building larger-scale, diverse benchmarks, exploring novel model architectures, and improving training techniques. These works aim to produce visually pleasing outputs, often measured by conventional metrics like PSNR or SSIM [54], or through human evaluations, without considering downstream recognition performance of the output. + +There exists a number of works relating image processing to image recognition performance, or machine-oriented image processing. Some works [17, 18, 34, 60] use image recognition accuracy as supplementary metrics besides + +![](images/90ccee828a535faba6416e26bc767b0ff615fb739efd224647c3cfd340377fd3.jpg) +Figure 2. The architecture of the proposed multilayer Laplacian resizer (MULLER). The resizer decomposes the input image into multiple layers of Laplacian residuals and then adds them back to the default resized image. The MULLER resizer is jointly trained with the downstream recognition model. + +visual quality metrics to evaluate the performance of image restoration models. Towards recognition-aware training, [10] proposed to train super-resolution using object detection loss and show promising results over conventional methods. Other works [39, 42] introduce pre-editing networks before image compression to improve compression efficiency without sacrificing classification accuracy. Recently, Liu et al. [26] developed an approach to train the processing models under the objective of image recognition accuracy, and investigated the efficacy of popular preprocessing operations such as super-resolution, denoising, and JPEG-deblocking on improving recognition performance. More similar studies [16, 22, 23, 36] have been conducted to jointly train a processing model like denoising, dehazing, face reconstruction, together with recognition model to achieve better image processing for recognition quality. + +# 3. Proposed Approach + +In this section, we introduce our proposed multilayer Laplacian resizer (MULLER, overviewed in Fig. 2), and discuss how we employ it for training several popular vision tasks. Unlike previous proposed resizers [3, 45], we aim to keep the computational cost of the model as low as possible such that it can replace existing resizers (e.g., bilinear) without extra cost, but also there is a notable performance gain. Our proposed approach is different in that (1) it is orders of magnitude faster, hence more scalable (to large image size), (2) it only has a handful of parameters which allows for better generalization, (3) it adds almost no extra training cost to the system. We show that with learning merely a couple of parameters, training with an added resizing module performs as effective as having a heavy downscaling network with several thousand parameter counts. + +# 3.1. Resizer Model + +Image resizing models can be generally formulated as: + +$$ +\mathbf {y} = \mathbf {F} _ {2} \left(\mathbf {R} \left(\mathbf {F} _ {1} (\mathbf {x}); h ^ {\prime}, w ^ {\prime}\right)\right), \tag {1} +$$ + +where $\mathbf{R}$ maps the input image $\mathbf{x}$ of size $h\times w$ to an output image of size $h^{\prime}\times w^{\prime}$ by computing the pixel values at the target spatial locations. $\mathbf{F}_1$ and $\mathbf{F}_2$ denote optional pre- and post-filtering operations. Typically, $\mathbf{F}_1$ and $\mathbf{F}_2$ can be identity functions, and $\mathbf{R}$ is chosen as a simple interpolation method like nearest-neighbor, bilinear, or bicubic. To learn more powerful resizing, learned resize has been proposed [3,4,45] by applying a base resizer on intermediate neural activations, wherein $\mathbf{F}_1$ and $\mathbf{F}_2$ are two designed CNNs applied at the original and output resolutions, respectively. Despite showing promising performance, however, these resize typically suffer from high computational complexity, and thus their net performance gain might be compromised in terms of the overall inference cost. + +# 3.2. Proposed MULLER Resizer + +We are inspired by the observations that these different learned resize, if properly regularized, will often learn to enhance edges, details, or sharpness of the image to benefit downstream tasks [3, 4]. To this end, we present to date, the simplest learned resizing model, using multilayer Laplacian decomposition, that is able to achieve 'bandpassed' detail and texture manipulation with only a handful of learnable parameters. Fig. 2 shows the architecture of the proposed MULLER resize. MULLER has the following form: + +$$ +\mathbf {z} = \underbrace {\mathbf {R} (\mathbf {x})} _ {\text {B a s e i m a g e}} + \sum_ {\ell = 1} ^ {k} \underbrace {\sigma \left(\alpha_ {\ell} \left(\mathbf {R} \left(\left(\mathbf {W} _ {\ell} - \mathbf {W} _ {\ell + 1}\right) \mathbf {x}\right) + \beta_ {\ell}\right)\right)} _ {\text {E n h a n c e d d e t a i l s i n e a c h s u b b a n d}}, \tag {2} +$$ + +where $\mathbf{R}$ denotes the base resizer (e.g. bilinear) and $\{\mathbf{W}_1, \mathbf{W}_2, \dots, \mathbf{W}_k\}$ represents the low-pass filter basis. We define $\mathbf{W}_{\ell}$ as a positive row-stochastic matrix [27] of size $n \times n$ , with $n$ representing the number of pixels in the vectorized input image $\mathbf{x}$ . Note that we assume $\mathbf{W}_{k+1} = \mathbf{I}$ , where $\mathbf{I}$ is the identity matrix. Each layer in Eq. (2) (see Fig. 2) uses a difference of the filters to decompose the image into different detail layers (bandpass filtering). + +Without loss of generality, we choose the Gaussian kernel as our base filter, and generate the filter bank by an iter- + +ative application of the same base filter as $\mathbf{W}_{\ell} = \mathbf{W}^{k - \ell +1}$ with $\mathbf{W}$ being a Gaussian filter with standard deviation 1. Note that the iterative application of the low-pass filter results in a smoother image. The filtered subband image $(\mathbf{W}_{\ell} - \mathbf{W}_{\ell +1})\mathbf{x}$ in brach $\ell$ is fed into the base resizer to produce the target resolution layer. We add trainable scaling and bias parameters $(\alpha_{\ell},\beta_{\ell})$ per layer to modulate and shift the resized response. Then, a nonlinearity function $\sigma$ (e.g., tanh) is applied on the resulting image layer, and finally the output is added to the base resized image. Note that the scaling factor $\alpha_{\ell}$ controls the amount of detail boosted or suppressed in layer $l$ of the resizer, and the bias parameter $\beta_{\ell}$ controls the mean shift. + +It is worth pointing out that in this framework, only the scalar and the bias values in the residual layers are trainable, meaning that for $k = 3$ , there are only six trainable parameters, and the overall computational cost is only applying 4 bilinear resizers and 3 Gaussian filters. Note that the term "Laplacian" refers to an interpretation of the filtering structure in Fig. 2 that can be written as a summation of Laplacian operators, namely $\mathbf{L}_{\ell} = \mathbf{I} - \mathbf{W}_{\ell}$ . More explicitly, for a linear activation, the resulting image $\mathbf{y}$ can be expressed as a Laplacian form [43]: + +$$ +\mathbf {y} = \gamma_ {0} \mathbf {R} (\mathbf {x}) + \gamma_ {1} \mathbf {R} (\mathbf {L} _ {1} \mathbf {x}) + \dots + \gamma_ {k} \mathbf {R} (\mathbf {L} _ {k} \mathbf {x}) + \delta , \tag {3} +$$ + +# 3.3. Applications in Vision Tasks + +While theoretically the resizer can be a drop-in replacement of the default resizer anywhere in the data generation and machine learning pipeline, we mainly demonstrate its ability to learn more informative thumbnail images for downstream recognition and detection tasks, which account for most of the practical use cases. We showcase the impact of MULLER by jointly training it with the backbone, where the resizer takes a higher-resolution image from the data pipeline and downscales it to lower-size before feeding as the model inputs. Since the proposed resizer is strongly regularized by its design, it needs no extra intermediate loss to train. The resizer is also task agnostic as no specific changes are needed to train with it in any framework on any vision or even vision-language tasks. + +# 4. Experiments + +We validate the performance of our proposed MULLER resizer on several competitive vision tasks on which resolution plays an important role on performance, including image classification, object detection and segmentation, and image quality assessment. In order to showcase the impact of MULLER, our main experiments include the state-of-the-art vision Transformer model MaxViT [50] as the baseline. We first demonstrate the performance of this baseline + +model by co-training it with MULLER. Then, we show that MULLER can be effective with other backbones such as ResNet [11], MobileNet-v2 [35] and EfficientNet-B0 [46]. In all the experiments, we use 2 layers in MULLER with Gaussian kernel size 5 and standard deviation 1. We use Tensorflow's default resizing as the base resizing. More experimental details can be found in supplementary materials. + +# 4.1. Main Experiments on ImageNet Classification + +We demonstrate the efficacy of the MULLER resizer on the standard, but most competitive ImageNet-1K classification task [15]. We take a top-performing vision Transformer, MaxViT [50], as the backbone model, and pre-train it on ImageNet-1K at $224 \times 224$ resolution for 300 epochs. Instead of directly fine-tuning at higher resolution (e.g., 384 or 512) like previous practices [8,9,24,50], we jointly fine-tune the backbone with the MULLER resizer plugged before the stem layers. We set input and output resolutions as 512 and 224 for MULLER in the ImageNet experiments. + +ImageNet-1K. The main results on ImageNet-1K classification are shown in Tab. 1. Note that we include all the state-of-the-art models trained to their highest possible accuracy reported in the original papers. For better visualization, we draw the accuracy vs. FLOPs and accuracy vs. inference-latency scaling curves in Fig. 3, respectively. As may be seen, MaxViT powered by the MULLER resizer sets a new state-of-the-art top-1 accuracy $85.68\%$ with only 43.9B FLOPs among all the compared models trained at 224x224. MULLER improves at an average of 0.49 accuracy across the four MaxViT variants. In terms of actual inference time, MaxViT with MULLER exceeds among all the models trained at various resolution - equivalently, it can save $36\%$ latency to achieve $\sim 85.7\%$ accuracy. + +ImageNet-21K and JFT. To demonstrate the scaling properties of the MULLER resizer with respect to data size, in Tab. 2 we report the results of the models pre-trained on ImageNet-21K and JFT-300M [38], respectively. It can be seen that with ImageNet-21k pretraining, the finetuned MaxViT with MULLER $_{512 \rightarrow 224}$ gains $0.8\%$ , $0.6\%$ , and $0.7\%$ accuracy over directly finetuning without resizer for B, L, and XL models, respectively. Similarly for JFT-300M pretraining, those numbers are $0.8\%$ , $0.7\%$ , and $0.7\%$ . It indicates that when finetuning with MULLER, MaxViT scales consistently when data size increases from ImageNet-1k up to JFT-300M. + +We further observe that for larger models and larger training sets, the backbone can benefit even more through seeing larger input images. Thus, we also report the performance of training with $\mathrm{MULLER}_{576\rightarrow 288}$ . We can see that it further boosts the performance by an average of $0.4\sim 0.5\%$ across the board for both 21K and JFT. Remarkably, MaxViT-XL with $\mathrm{MULLER}_{576\rightarrow 288}$ achieves $89.16\%$ top-1 accuracy with only 162.9B FLOPs. + +
ModelEval sizeParamsFLOPsThr (img/s)IN-1K top-1 acc
EffNetV2-S [47]38424M8.8B666.683.9
EffNetV2-M [47]48055M24.0B280.785.1
ConvNeXt-T [25]22429M4.5B77482.1
ConvNeXt-S [25]22450M8.7B447.183.1
ConvNeXt-B [25]22489M15.4B292.183.8
ConvNeXt-L [25]224198M34.4B146.884.3
ViT-B/32 [9]38486M55.4B85.977.9
ViT-B/16 [9]384307M190.7B27.376.5
Swin-T [24]22429M4.5B755.281.3
Swin-S [24]22450M8.7B436.983.0
Swin-B [24]22488M15.4B278.183.5
CSwin-B [8]22423M4.3B70182.7
CSwin-B [8]22435M6.9B43783.6
CSwin-B [8]22478M15.0B25084.2
CoAtNet-0 [7]22425M4.2B52681.6
CoAtNet-1 [7]22425M4.2B33683.3
CoAtNet-2 [7]22475M15.7B247.784.1
CoAtNet-3 [7]224168M34.7B163.384.5
MaxViT-T22431M5.6B350.483.62
+MULLER512→22422431M5.63B349.683.95
MaxViT-S22469M11.7B242.584.45
+MULLER512→22422469M11.73B241.484.95
MaxViT-B224120M23.4B133.684.95
+MULLER512→224224120M23.43B133.085.58
MaxViT-L224212M43.9B99.485.17
+MULLER512→224224212M43.93B99.385.68
+ +Table 1. Performance comparison under the ImageNet-1K setting. MULLER $_{\mathrm{A} \rightarrow \mathrm{B}}$ denote that MULLER resizes from A to B, where the backbone takes images of size B. FLOPs counts the total computation of the resolver and backbone. Throughput (Thr) is measured on a single V100 GPU with batch size 16, following [24,25,47]. $\bullet$ , $\diamond$ , and $\diamond$ denote ConvNets, Transformers, and hybrid models, respectively. + +We also examine the generalization of the resizer across different model variants. We found that the learned weights in MULLER are very close across different variants, and the transferring results are as effective as the original training. Detailed results are in the supplementary materials. Note that we present our generalization experiments across different backbones in the next section. + +# 4.2. Different Backbones + +Main results. To explore the resizer beyond the MaxViT architecture, we selected some widely used backbones including ResNet-50 [11], EfficientNet-B0 [46], and MobileNetv2 [35]. Our results are presented in Tab. 3. We also make comparisons with the resizer of Talebi et al. [45]. We observed that the proposed resizer improves the performance of the baseline backbones consistently. Also compared to + +![](images/978247de0b4f8035fa63b6c7a95cf301ff15da7578d21d60bc27f360adfa9c59.jpg) + +![](images/d3d7c435ed39b86c6773f1fdc0ea9c12e76a14857b4ce25423ecffb23851c375.jpg) +Figure 3. Model FLOPs (top), and Inference Latency (bottom) performance comparison of state-of-the-art vision backbones on ImageNet-1K. We show that MaxViT trained with MULLER resizer yielded the best accuracy vs. computation and accuracy vs. inference-cost tradeoff. Note that top figure includes only $224 \times 224$ models whereas the bottom figures include the best possible performance curves among various training size. Inference time is calculated by the throughput in Tab. 1. + +[46], MULLER requires a significantly lower number of FLOPs (two orders-of-magnitude), and in some cases such as MobileNet-v2 and EfficientNet-B0 it outperforms [45]. These results also indicate that MULLER improves over baseline resizers low the FLOPs regime as well. + +Cross-model Generalization. In order to examine the generalizability of MULLER, we evaluate classification models with resizers that are trained with other backbones. To this end, we first present the learned resizer parameters for each backbone, and then discuss the classification performances. + +Results in Tab. 4 represent the learned MULLER parameters (see Eq. 2) for each backbone model trained on ImageNet-1k. We observed that (1) performance of the clas + +
ModelEval sizeParamsFLOPsIN-1K top-1 acc.
21K-ptJFT-pt
BiT-R-101x3 [14]384388M204.6B84.4-
BiT-R-152x4 [14]480937M840.5B85.4-
EffNetV2-L [47]480121M53.0B86.8-
EffNetV2-XL [47]512208M94.0B87.3-
ConvNeXt-L [25]384198M101.0B87.5-
ConvNeXt-XL [25]384350M179.0B87.8-
NFNet-F4+ [2]512527M367B-89.20
ViT-B/16 [9]38487M55.5B84.0-
ViT-L/16 [9]384305M191.1B85.2
ViT-L/16 [9]512305M364B-87.76
ViT-H/14 [9]518632M1021B-88.55
HaloNet-H4 [52]51285M-85.8-
SwinV2-B [24]38488M-87.1-
SwinV2-L [24]384197M-87.7-
CvT-W24 [55]384277M193.2B87.7-
R+ViT-L/16 [9]384330M--87.12
CoAtNet-3 [7]384168M107.4B87.688.52
CoAtNet-3 [7]512168M214B87.988.81
CoAtNet-4 [7]512275M360.9B88.189.11
MaxViT-B224119M23.4B86.6387.05
+MULLER512→224224119M23.4B87.4087.82
+MULLER576→288288119M40.6B87.9288.39
MaxViT-L224212M43.9B86.8687.72
+MULLER512→224224212M43.9B87.4888.43
+MULLER576→288288212M73.4B87.9488.87
MaxViT-XL224475M97.8B87.2588.06
+MULLER512→224224475M97.8B87.9088.74
+MULLER576→288288475M162.9B88.3189.16
MaxViT-B512119M138.3B88.3888.82
MaxViT-L512212M245.2B88.4689.41
MaxViT-XL512475M535.2B88.7089.53
+ +sification models are more sensitive to $\alpha_{1}$ than $\alpha_{2}$ , and (2) the learned bias values are relatively small, meaning the resizer does not significantly shift the mean of each residual image layer. Note that $|\alpha_{\ell}| > 1$ means the image details represented by the $\ell$ -th layer are boosted, whereas $|\alpha_{\ell}| < 1$ has the opposite effect. + +To quantify generalizability of the resizer, we used the learned parameters in Tab. 4 to evaluate different backbones. As for different backbones, Tab. 5 shows that one model leads to classification performance that is in the average proximity of 0.15 from the best top-1 accuracy. We believe this can be explained by the fact that MULLER is a + +Table 2. Performance comparison for large-scale data regimes: ImageNet-21K and JFT pretrained models. We report results using two different settings: $\mathrm{MULLER}_{512\rightarrow 224}$ and $\mathrm{MULLER}_{576\rightarrow 288}$ respectively, as we observe that on larger models and larger training sets, the backbone benefits more by seeing larger inputs. + +
ModelSizeFLOPstop-1 acc.
EffNet-B0 [46]2240.39B77.1
+ [45]512→2242242.63B77.9
+MULLER512→2242240.42B78.2
MobileNet-v2 [35]2240.60B70.5
+ [45]512→2242242.84B71.5
+MULLER512→2242240.63B71.8
ResNet-50 [11]2246.97B75.3
+ [45]512→2242249.33B76.2
+MULLER512→2242247.0B76.2
+ +Table 3. Performance comparison under ImageNet-1K setting with different backbones. + +
Modelα1β1α2β2
EffNet-B0 [46]1.7150.088-8.410.001
MobileNet-v2 [35]1.4800.174-5.25-0.058
ResNet-50 [11]1.892-0.014-11.2950.003
+ +Table 4. The learned MULLER parameters for different backbone models train on ImageNet-1k. + +
ModelEffNet-B0MobileNet-v2ResNet-50
MULLEREffNet78.271.675.9
MULLERMobileNet78.071.876.0
MULLERResNet78.171.776.2
+ +Table 5. Cross-model validation of the MULLER resolver for ImageNet-1K on different backbones. + +constrained model with only 4 trainable parameters. Also, it is important to highlight that in contrast to the resizer in [45], MULLER does not require fine-tuning. + +Impact of Aliasing. It has been shown that aliasing may impact the performance of some deep vision models [29,51]. It is worth mentioning that the results presented in this section are based on anti-aliased images. More specifically, we used the AREA downscaling method in TensorFlow to produce $512^{2}$ inputs to MULLER. We observed that while removing anti-aliasing does not hamper the overall performance gain obtained by MULLER, the learned parameters may differ from Tab. 4. We will present our results without anti-aliasing in the supplementary material. + +# 4.3. Downstream tasks + +Object Detection and Instance Segmentation. We evaluated the performance of MULLER on COCO2017 [21] for object bounding box detection and instance segmentation tasks with a two-stage cascaded Mask-RCNN framework [31]. We warm start the MaxViT backbone using checkpoints pretrained on ImageNet-1K, then finetune the whole model including the resizing on COCO. + +Tab. 6 summarizes the object detection and instance seg + +
BackboneResolutionAP\( AP_{50} \)\( AP_{75} \)\( AP^m \)\( AP_{50}^m \)\( AP_{75}^m \)FLOPs
•ResNet-50 [11]1280×80046.364.350.540.161.743.4739B
•X101-32 [56]1280×80048.166.552.441.663.945.2819B
•X101-64 [56]1280×80048.366.452.341.764.045.1972B
•ConvNeXt-T [25]1280×80050.469.154.843.766.547.3741B
•ConvNeXt-S [25]1280×80051.970.856.545.068.449.1827B
•ConvNeXt-B [25]1280×80052.771.357.245.668.949.5964B
○Swin-T [24]1280×80050.469.254.743.766.647.3745B
○Swin-S [24]1280×80051.970.756.345.068.248.8838B
○Swin-B [24]1280×80051.970.556.445.068.148.9982B
○UViT-T [6]896×89651.170.456.243.667.747.2613B
○UViT-S [6]896×89651.470.856.244.168.248.0744B
○UViT-B [6]896×89652.572.057.644.368.748.3975B
○MaxViT-T640×64049.969.954.642.766.646.4379B
○+MULR896→640640×64050.570.755.043.167.046.7379B
○MaxViT-S640×64050.570.255.343.367.346.8432B
○+MULR896→640640×64050.870.455.543.567.747.1432B
○MaxViT-B640×64051.671.356.144.168.547.7543B
○+MULR896→640640×64052.371.557.044.768.948.7543B
○MaxViT-T896×89652.171.956.844.669.148.4475B
○MaxViT-S896×89653.172.558.145.469.849.5595B
○MaxViT-B896×89653.472.958.145.770.350.0856B
+ +mentation results comparing state-of-the-art ConvNets and vision Transformers. AP and $\mathrm{AP}^m$ denote box and mask average precision. We report the train and evaluation resolutions as well as their corresponding FLOPs as reference for model complexity. It may be seen that MaxViT suffers from noticeable performance drop if training resolution is lower. However, we observed that training with the MULLER resized can further improve the performance across the board. Specifically, on MaxViT-B at $640 \times 640$ , finetuning with MULLER gains 0.7 AP and 0.6 mask AP on the COCO validation set without any FLOPs overhead. + +Image Quality Assessment. We base our experiment on the AVA dataset [28], which includes 250K images rated by amateur photographers. Each image in the dataset is associated with a histogram of ratings from an average of 200 raters. Image quality and aesthetic assessment is a task that is sensitive to downscaling [13], as downscaling may negatively impact visual quality attributes such as sharpness. We use the Earth Mover's Distance (EMD) as our training loss, similar to previous work of [44]. + +Our results are shown in Tab. 7. We report the Pearson linear correlation coefficient (PLCC) of the predicted and ground truth mean ratings as our evaluation metric. As can be seen, the proposed resizer improves the performance of MaxViT beyond the existing methods such as MUSIQ [13]. Note that in contrast to MUSIQ which uses multi-scale in + +Table 6. Comparison of two-stage object detection and instance segmentation on COCO2017. All models are pretrained on ImageNet-1K. + +
ModelSizeParamsPLCC↑
•NIMA [44]22456M0.636
•+ [45]512→22422456M0.680
•EffNet-B0 [46]2245.3M0.642
•+ [45]512→2242245.3M0.650
•AFDC [5]22444.5M0.671
○ViT-S/32 [13]38422M0.665
○ViT-B/32 [13]38488M0.664
○MUSIQ [13]224~51227M0.720
◇MaxViT-T22431M0.707
◇+MULLER512→22422431M0.729
+ +Table 7. Image aesthetic assessment results on the AVA benchmark [28]. PLCC represents the Pearson's linear correlation coefficient. + +
nlayersksizestdTop-1 AccFLOPs
251.085.5824.23B
351.085.5224.24B
451.085.5024.25B
651.085.5924.27B
231.085.4824.23B
271.085.5724.24B
251.585.5624.24B
252.085.5324.24B
+ +Table 8. Hyperparameter sweep for MULLER. + +
input sizeoutput sizeTop-1 AccFLOPs
38422485.4524.22B
51222485.5824.23B
76822485.5624.26B
51238486.4274.25B
76838486.4474.28B
76851286.68138.57B
102451286.67138.60B
+ +Table 9. Effects of input and output size for MULLER using MaxViT-Base as test backkBone. Note that the output size is the image size seen by the backbone. + +put augmentations, MULLER+MaxViT only requires a single low-resolution input from the resizing. + +# 4.4. Ablation + +Hyperparameters. There are three hyperparameters in the design of MULLER: $\{k, hsize, stddev\}$ , which denote the number of layers, the kernel size of the Gaussian filters $\{\mathbf{W}_1, \mathbf{W}_2, \dots, \mathbf{W}_k\}$ , and the standard deviation of the Gaussian filters. To understand the effect of these hyperparameters, we conduct an ablation study. As shown in Tab. 8, we found that MULLER is quite insensitive to the selection + +![](images/8b9c5c1238018d1e12adef7cddd12a96661bfe1f16778e243d0d080f96e67335.jpg) + +![](images/a7b962ec181b2d97062e6d654a552df3ac8e697c6595e933086305a40939e6d6.jpg) +(a) Original + +![](images/e786e0e5496ae7cca9e8ea764837dfc4dd73d1e036eac00bdc68d5641c302f1c.jpg) + +![](images/8134e7efcf639f24606e45fc147c20a6f0440d32eb38c749d40319061779e355.jpg) +(b) Default resizer + +![](images/c011fae887eaeb90b297ea9a748ddde12c0cdb3edacdf5d84d7aa4f09007512c.jpg) + +![](images/1dbce26ee9e4edf0eddc9af9cc18ba6b6759ba29f36ba6d3ff51c8c3b1b77e1a.jpg) +(c) Learned resizer +Figure 4. Visualizations of the learned MULLER resizer for ResNet-50. Here the default resizer is an (anti-aliased) AREA resizer in Tensorflow. (d) shows the difference of the learned and the default resizers. + +![](images/672abccec551ea0d900c31bcd304faf54d4d870d59f552714e807fe2487eb762.jpg) + +![](images/9eaf1819e7835e952cbf55e12298922016bdd0afabd7a22bb6fc2730ef235ddf.jpg) +(d) Difference + +of parameters, and thus we recommend to use a simple set of parameters to save computation. + +Effects of image size. It is known that image size can significantly affect the recognition performance. We evaluate the effect of varying input and output sizes of MULLER using MaxViT-B in Tab. 9. Note that the output size of MULLER is indeed the size seen by the backbone, so higher output size typically corresponds to improved accuracy. We observe that using higher input resolutions (e.g., $3 \times$ ) for MULLER does not yield any further performance gain beyond the baseline setting. Nonetheless, we find that adopting a reasonably large resolution (e.g. $1.6 \sim 2.5 \times$ ) is necessary to achieve the expected performance. It is worth highlighting that this is perhaps impacted by the original resolution of images in the benchmark dataset. + +# 4.5. Visualization + +We visualize the behavior of the learned resizer in Fig. 4. As can be seen, the MULLER resizer is learned to boost details or textures of the images, while also enhancing the image contrast. These effects can preserve more visual information in the downscaled images over naive resizing, thus making the classification model learn better. As compared to the previous less-controlled resizer [45], MULLER achieves a better balance of human and machine perceptual qualities, due to the strong regularization imbued in its Laplacian-inspired design. We also point out that training MULLER with aliased inputs may produce relatively less sharper images in comparison to Fig. 4. We refer the reader to the supplementary material for visual examples. + +# 5. Concluding Remarks + +In this paper, we introduce MULLER, an extremely simple and light learned resizer, using multilayer Laplacian decomposition. The proposed resizer only contains 4 trainable parameters with negligible training and inference costs. This allows deploying the resizer as a thumbnail generator to produce optimally downscaled images for sending to remote inference servers, or alternatively as a server side resizer that reduces the inference cost without the necessity of changing the backbone architecture. We show that MULLER not only pushes forward the limit of the state-of-the-art vision Transformer MaxViT on ImageNet classification, but it also consistently improves across a range of widely used architectures, including EfficientNet, MobileNet, and ResNet. Additionally, we provide experiments to substantiate the efficacy of MULLER for various downstream tasks, such as object detection, segmentation, and image quality assessment. As compared to previous methods, MULLER enjoys remarkable generalization ability, owing to the strong regularization provided by its multilayer bandpass design. We believe that our work will inspire future research in this critically important direction: how to better preprocess images for vision tasks. + +Limitations and future works. We note that if the higher-resolution inputs fail to boost the performance of an specific task, we cannot reasonably expect the learned resizer to provide a substantial performance boost either. Another potential future direction is to train a universal learned resizer that can be a drop-in replacement of the off-the-shelf resizers in existing machine learning frameworks, without necessitating the joint re-training of the backbones. + +# References + +[1] Martín Abadi, Ashish Agarwal, Paul Barham, Eugene Brevdo, Zhifeng Chen, Craig Citro, Greg S Corrado, Andy Davis, Jeffrey Dean, Matthieu Devin, et al. Tensorflow: Large-scale machine learning on heterogeneous distributed systems. arXiv preprint arXiv:1603.04467, 2016. 1 +[2] Andy Brock, Soham De, Samuel L Smith, and Karen Simonyan. High-performance large-scale image recognition without normalization. In International Conference on Machine Learning, pages 1059-1071. PMLR, 2021. 6 +[3] Li-Heng Chen, Christos G Bampis, Zhi Li, Lukáš Krasula, and Alan C Bovik. Estimating the resize parameter in end-to-end learned image compression. arXiv preprint arXiv:2204.12022, 2022. 2, 3 +[4] Li-Heng Chen, Christos G Bampis, Zhi Li, Joel Sole, and Alan C Bovik. A progressive architecture for learned fractional downsampling. In 2021 Picture Coding Symposium (PCS), pages 1-5. IEEE, 2021. 2, 3 +[5] Qiuyu Chen, Wei Zhang, Ning Zhou, Peng Lei, Yi Xu, Yu Zheng, and Jianping Fan. Adaptive fractional dilated convolution network for image aesthetics assessment. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14114-14123, 2020. 7 +[6] Wuyang Chen, Xianzhi Du, Fan Yang, Lucas Beyer, Xiaohua Zhai, Tsung-Yi Lin, Huizhong Chen, Jing Li, Xiaodan Song, Zhangyang Wang, and Denny Zhou. A simple single-scale vision transformer for object localization and instance segmentation. CoRR, abs/2112.09747, 2021. 7 +[7] Zihang Dai, Hanxiao Liu, Quoc Le, and Mingxing Tan. Coatnet: Marrying convolution and attention for all data sizes. Advances in Neural Information Processing Systems, 34, 2021. 5, 6 +[8] Xiaoyi Dong, Jianmin Bao, Dongdong Chen, Weiming Zhang, Nenghai Yu, Lu Yuan, Dong Chen, and Baining Guo. Cswin transformer: A general vision transformer backbone with cross-shaped windows. arXiv preprint arXiv:2107.00652, 2021. 4, 5 +[9] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020.4,5,6 +[10] Muhammad Haris, Greg Shakhnarovich, and Norimichi Ukita. Task-driven super resolution: Object detection in low-resolution images. In Neural Information Processing: 28th International Conference, ICONIP 2021, Sanur, Bali, Indonesia, December 8-12, 2021, Proceedings, Part V 28, pages 387-395. Springer, 2021. 3 +[11] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 1, 4, 5, 6, 7 +[12] Gao Huang, Zhuang Liu, Laurens Van Der Maaten, and Kilian Q Weinberger. Densely connected convolutional networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4700-4708, 2017. 1 + +[13] Junjie Ke, Qifei Wang, Yilin Wang, Peyman Milanfar, and Feng Yang. Musiq: Multi-scale image quality transformer. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 5148-5157, 2021. 7 +[14] Alexander Kolesnikov, Lucas Beyer, Xiaohua Zhai, Joan Puigcerver, Jessica Yung, Sylvain Gelly, and Neil Houlsby. Big transfer (bit): General visual representation learning. In European conference on computer vision, pages 491-507. Springer, 2020. 6 +[15] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E Hinton. Imagenet classification with deep convolutional neural networks. Advances in neural information processing systems, 25, 2012. 1, 4 +[16] Boyi Li, Xiulian Peng, Zhangyang Wang, Jizheng Xu, and Dan Feng. End-to-end united video dehazing and detection. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 32, 2018. 3 +[17] Boyi Li, Wenqi Ren, Dengpan Fu, Dacheng Tao, Dan Feng, Wenjun Zeng, and Zhangyang Wang. Benchmarking single-image dehazing and beyond. IEEE Transactions on Image Processing, 28(1):492-505, 2018. 2 +[18] Siyuan Li, Iago Bruno Araujo, Wenqi Ren, Zhangyang Wang, Eric K Tokuda, Roberto Hirata Junior, Roberto Cesar-Junior, Jiawan Zhang, Xiaojie Guo, and Xiaochun Cao. Single image deraining: A comprehensive benchmark analysis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3838-3847, 2019. 2 +[19] Yinxiao Li, Pengchong Jin, Feng Yang, Ce Liu, Ming-Hsuan Yang, and Peyman Milanfar. Comisr: Compression-informed video super-resolution. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2543-2552, 2021. 2 +[20] Yue Li, Dong Liu, Houqiang Li, Li Li, Zhu Li, and Feng Wu. Learning a convolutional neural network for image compact-resolution. IEEE Transactions on Image Processing, 28(3):1092-1107, 2018. 2 +[21] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In European conference on computer vision, pages 740-755. Springer, 2014. 6 +[22] Ding Liu, Bihan Wen, Xianming Liu, Zhangyang Wang, and Thomas S Huang. When image denoising meets high-level vision tasks: A deep learning approach. arXiv preprint arXiv:1706.04284, 2017. 3 +[23] Feng Liu, Ronghang Zhu, Dan Zeng, Qijun Zhao, and Xiaoming Liu. Disentangling features in 3d face shapes for joint face reconstruction and recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5216-5225, 2018. 3 +[24] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10012-10022, 2021. 1, 4, 5, 6, 7 +[25] Zhuang Liu, Hanzi Mao, Chao-Yuan Wu, Christoph Feichtenhofer, Trevor Darrell, and Saining Xie. A convnet for the 2020s. arXiv preprint arXiv:2201.03545, 2022. 5, 6, 7 + +[26] Zhuang Liu, Tinghui Zhou, Hung-Ju Wang, Zhiqiang Shen, Bingyi Kang, Evan Shelhamer, and Trevor Darrell. Transferable recognition-aware image processing. arXiv preprint arXiv:1910.09185, 2019. 3 +[27] Peyman Milanfar. A tour of modern image filtering: New insights and methods, both practical and theoretical. IEEE signal processing magazine, 30(1):106-128, 2012. 3 +[28] Naila Murray, Luca Marchesotti, and Florent Perronnin. Ava: A large-scale database for aesthetic visual analysis. In 2012 IEEE conference on computer vision and pattern recognition, pages 2408-2415. IEEE, 2012. 7 +[29] Gaurav Parmar, Richard Zhang, and Jun-Yan Zhu. On buggy resizing libraries and surprising subtleties in fid calculation. arXiv preprint arXiv:2104.11222, 2021. 2, 6 +[30] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, Luca Antiga, et al. Pytorch: An imperative style, high-performance deep learning library. Advances in neural information processing systems, 32, 2019. 1 +[31] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. In C. Cortes, N. Lawrence, D. Lee, M. Sugiyama, and R. Garnett, editors, Advances in Neural Information Processing Systems, volume 28. Curran Associates, Inc., 2015. 6 +[32] Rachid Riad, Olivier Teboul, David Grangier, and Neil Zeghidour. Learning strides in convolutional neural networks. arXiv preprint arXiv:2202.01653, 2022. 2 +[33] Avinab Saha, Sandeep Mishra, and Alan C Bovik. Reiaq: Unsupervised learning for image quality assessment in the wild. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5846-5855, 2023. 1 +[34] Mehdi SM Sajjadi, Bernhard Scholkopf, and Michael Hirsch. Enhancenet: Single image super-resolution through automated texture synthesis. arXiv preprint arXiv:1612.07919, 2016. 2 +[35] Mark Sandler, Andrew Howard, Menglong Zhu, Andrey Zh-moginov, and Liang-Chieh Chen. Mobilenetv2: Inverted residuals and linear bottlenecks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4510-4520, 2018. 1, 4, 5, 6 +[36] Vivek Sharma, Ali Diba, Davy Neven, Michael S Brown, Luc Van Gool, and Rainer Stiefelhagen. Classification-driven dynamic image enhancement. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4033-4041, 2018. 3 +[37] Wenzhe Shi, Jose Caballero, Ferenc Huszár, Johannes Totz, Andrew P Aitken, Rob Bishop, Daniel Rueckert, and Zehan Wang. Real-time single image and video super-resolution using an efficient sub-pixel convolutional neural network. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1874-1883, 2016. 2 +[38] Chen Sun, Abhinav Shrivastava, Saurabh Singh, and Abhinav Gupta. Revisiting unreasonable effectiveness of data in deep learning era. In Proceedings of the IEEE international conference on computer vision, pages 843-852, 2017. 4 + +[39] Satoshi Suzuki, Motohiro Takagi, Kazuya Hayase, Takayuki Onishi, and Atsushi Shimizu. Image pre-transformation for recognition-aware image compression. In 2019 IEEE International Conference on Image Processing (ICIP), pages 2686-2690. IEEE, 2019. 3 +[40] Christian Szegedy, Wei Liu, Yangqing Jia, Pierre Sermanet, Scott Reed, Dragomir Anguelov, Dumitru Erhan, Vincent Vanhoucke, and Andrew Rabinovich. Going deeper with convolutions. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1-9, 2015. 1 +[41] Christian Szegedy, Vincent Vanhoucke, Sergey Ioffe, Jon Shlens, and Zbigniew Wojna. Rethinking the inception architecture for computer vision. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2818-2826, 2016. 1 +[42] Hossein Talebi, Damien Kelly, Xiyang Luo, Ignacio Garcia Dorado, Feng Yang, Peyman Milanfar, and Michael Elad. Better compression with deep pre-editing. IEEE Transactions on Image Processing, 30:6673-6685, 2021. 3 +[43] Hossein Talebi and Peyman Milanfar. Fast multilayer laplacian enhancement. IEEE Transactions on Computational Imaging, 2(4):496-509, 2016. 4 +[44] Hossein Talebi and Peyman Milanfar. Nima: Neural image assessment. IEEE transactions on image processing, 27(8):3998-4011, 2018. 7 +[45] Hossein Talebi and Peyman Milanfar. Learning to resize images for computer vision tasks. In Proceedings of the IEEE/CVF international conference on computer vision, pages 497-506, 2021. 2, 3, 5, 6, 7, 8 +[46] Mingxing Tan and Quoc Le. Efficientnet: Rethinking model scaling for convolutional neural networks. In International conference on machine learning, pages 6105-6114. PMLR, 2019. 1, 4, 5, 6, 7 +[47] Mingxing Tan and Quoc Le. Efficientnetv2: Smaller models and faster training. In International Conference on Machine Learning, pages 10096-10106. PMLR, 2021. 5, 6 +[48] Xin Tao, Hongyun Gao, Xiaoyong Shen, Jue Wang, and Jiaya Jia. Scale-recurrent network for deep image deblurring. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 8174-8182, 2018. 2 +[49] Zhengzhong Tu, Hossein Talebi, Han Zhang, Feng Yang, Peyman Milanfar, Alan Bovik, and Yinxiao Li. Maxim: Multi-axis mlp for image processing. arXiv preprint arXiv:2201.02973, 2022. 2 +[50] Zhengzhong Tu, Hossein Talebi, Han Zhang, Feng Yang, Peyman Milanfar, Alan Bovik, and Yinxiao Li. Maxvit: Multi-axis vision transformer. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXIV, pages 459-479. Springer, 2022. 1, 2, 4 +[51] Cristina Vasconcelos, Hugo Larochelle, Vincent Dumoulin, Rob Romijnders, Nicolas Le Roux, and Ross Goroshin. Impact of aliasing on generalization in deep convolutional networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10529-10538, 2021. 6 +[52] Ashish Vaswani, Prajit Ramachandran, Aravind Srinivas, Niki Parmar, Blake Hechtman, and Jonathon Shlens. Scaling + +local self-attention for parameter efficient visual backbones. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12894–12904, 2021. 6 +[53] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. 1 +[54] Zhou Wang. Image quality assessment: from error visibility to structural similarity. IEEE transactions on image processing, 13(4):600-612, 2004. 2 +[55] Haiping Wu, Bin Xiao, Noel Codella, Mengchen Liu, Xiyang Dai, Lu Yuan, and Lei Zhang. Cvt: Introducing convolutions to vision transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 22-31, 2021. 6 +[56] Saining Xie, Ross Girshick, Piotr Dólár, Zhuowen Tu, and Kaiming He. Aggregated residual transformations for deep neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1492-1500, 2017. 7 +[57] Runsheng Xu, Jinlong Li, Xiaoyu Dong, Hongkai Yu, and Jiaqi Ma. Bridging the domain gap for multi-agent perception. arXiv preprint arXiv:2210.08451, 2022. 2 +[58] Runsheng Xu, Hao Xiang, Zhengzhong Tu, Xin Xia, Ming-Hsuan Yang, and Jiaqi Ma. V2x-vit: Vehicle-to-everything cooperative perception with vision transformer. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXXIX, pages 107-124. Springer, 2022. 1 +[59] Kai Zhang, Wangmeng Zuo, Yunjin Chen, Deyu Meng, and Lei Zhang. Beyond a gaussian denoiser: Residual learning of deep cnn for image denoising. IEEE transactions on image processing, 26(7):3142-3155, 2017. 2 +[60] Richard Zhang, Phillip Isola, and Alexei A Efros. Colorful image colorization. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part III 14, pages 649-666. Springer, 2016. 2 +[61] Chen Zhao and Bernard Ghanem. Thumbnet: One thumbnail image contains all you need for recognition. In Proceedings of the 28th ACM International Conference on Multimedia, pages 1506-1514, 2020. 2 \ No newline at end of file diff --git a/2023/MULLER_ Multilayer Laplacian Resizer for Vision/images.zip b/2023/MULLER_ Multilayer Laplacian Resizer for Vision/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..d79f0f7497900c577bca7e941b0db8a5a340728f --- /dev/null +++ b/2023/MULLER_ Multilayer Laplacian Resizer for Vision/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:b02daf9c07cdba9a1f4e547f020f6fe217302791bee7725b5914811aba959a93 +size 919067 diff --git a/2023/MULLER_ Multilayer Laplacian Resizer for Vision/layout.json b/2023/MULLER_ Multilayer Laplacian Resizer for Vision/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..04e71426f9f573455b68631b81dad335893b6f21 --- /dev/null +++ b/2023/MULLER_ Multilayer Laplacian Resizer for Vision/layout.json @@ -0,0 +1,8104 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 138, + 103, + 455, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 138, + 103, + 455, + 121 + ], + "spans": [ + { + "bbox": [ + 138, + 103, + 455, + 121 + ], + "type": "text", + "content": "MULLER: Multilayer Laplacian Resizer for Vision" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 175, + 143, + 419, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 175, + 143, + 419, + 171 + ], + "spans": [ + { + "bbox": [ + 175, + 143, + 419, + 171 + ], + "type": "text", + "content": "Zhengzhong Tu, Peyman Milanfar, Hossein Talebi \nGoogle Research" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 233, + 174, + 361, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 233, + 174, + 361, + 185 + ], + "spans": [ + { + "bbox": [ + 233, + 174, + 361, + 185 + ], + "type": "text", + "content": "zhengzhongtu@gmail.com" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "spans": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 239, + 290, + 586 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 239, + 290, + 586 + ], + "spans": [ + { + "bbox": [ + 47, + 239, + 290, + 586 + ], + "type": "text", + "content": "Image resizing operation is a fundamental preprocessing module in modern computer vision. Throughout the deep learning revolution, researchers have overlooked the potential of alternative resizing methods beyond the commonly used resize that are readily available, such as nearest-neighbors, bilinear, and bicubic. The key question of our interest is whether the front-end resize affects the performance of deep vision models? In this paper, we present an extremely lightweight multilayer Laplacian resolver with only a handful of trainable parameters, dubbed MULLER resolver. MULLER has a bandpass nature in that it learns to boost details in certain frequency subbands that benefit the downstream recognition models. We show that MULLER can be easily plugged into various training pipelines, and it effectively boosts the performance of the underlying vision task with little to no extra cost. Specifically, we select a state-of-the-art vision Transformer, MaxViT [50], as the baseline, and show that, if trained with MULLER, MaxViT gains up to " + }, + { + "bbox": [ + 47, + 239, + 290, + 586 + ], + "type": "inline_equation", + "content": "0.6\\%" + }, + { + "bbox": [ + 47, + 239, + 290, + 586 + ], + "type": "text", + "content": " top-1 accuracy, and meanwhile enjoys " + }, + { + "bbox": [ + 47, + 239, + 290, + 586 + ], + "type": "inline_equation", + "content": "36\\%" + }, + { + "bbox": [ + 47, + 239, + 290, + 586 + ], + "type": "text", + "content": " inference cost saving to achieve similar top-1 accuracy on ImageNet-1k, as compared to the standard training scheme. Notably, MULLER's performance also scales with model size and training data size such as ImageNet-21k and JFT, and it is widely applicable to multiple vision tasks, including image classification, object detection and segmentation, as well as image quality assessment. The code is available at https://github.com/google-research/google-research/tree/master/muller." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 609, + 128, + 621 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 609, + 128, + 621 + ], + "spans": [ + { + "bbox": [ + 47, + 609, + 128, + 621 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 629, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 287, + 715 + ], + "type": "text", + "content": "Most computer vision problems such as image classification, object detection, video recognition, and image/video generation have seen groundbreaking advancement by deep neural networks-based models that are trained on web-scale, human-curated datasets [11, 12, 15, 15, 24, 33, 35, 40, 41, 46, 53, 58]. In any of the underlining training infrastructures like Tensorflow [1] and PyTorch [30], image resizing" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 315, + 213, + 538, + 322 + ], + "blocks": [ + { + "bbox": [ + 315, + 213, + 538, + 322 + ], + "lines": [ + { + "bbox": [ + 315, + 213, + 538, + 322 + ], + "spans": [ + { + "bbox": [ + 315, + 213, + 538, + 322 + ], + "type": "image", + "image_path": "3e7a77c8b92bb54410178bb3d56bf75d6fbe88989d82a86de0b20bd59a5fdb9b.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 313, + 326, + 541, + 415 + ], + "blocks": [ + { + "bbox": [ + 313, + 326, + 541, + 415 + ], + "lines": [ + { + "bbox": [ + 313, + 326, + 541, + 415 + ], + "spans": [ + { + "bbox": [ + 313, + 326, + 541, + 415 + ], + "type": "image", + "image_path": "48a77002fff2f276b713f09dc160eb47a9ea71ad26b521b6e741d167fcf0729d.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 428, + 547, + 513 + ], + "lines": [ + { + "bbox": [ + 304, + 428, + 547, + 513 + ], + "spans": [ + { + "bbox": [ + 304, + 428, + 547, + 513 + ], + "type": "text", + "content": "Figure 1. Top: our proposed learned resizer can push forward a strong vision Transformer MaxViT [50] by up to " + }, + { + "bbox": [ + 304, + 428, + 547, + 513 + ], + "type": "inline_equation", + "content": "0.6\\%" + }, + { + "bbox": [ + 304, + 428, + 547, + 513 + ], + "type": "text", + "content": " top-1 accuracy on ImageNet-1K with no extra inference cost. Results for other backbones are shown in Sec. 4.2. Bottom: demonstration of the learned resizer - with detail-boosted input image, the classification accuracy of the exemplar image has improved." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 532, + 547, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 532, + 547, + 628 + ], + "spans": [ + { + "bbox": [ + 304, + 532, + 547, + 628 + ], + "type": "text", + "content": "is an essential preprocessing step which enables efficient gradient-based training of networks with millions of trainable parameters. Moreover, the factor of image size can sometimes significantly impact the performance of various tasks, particularly those requiring high-resolution prediction. Although neural architectures have been revolutionized by CNNs and Transformers, surprisingly limited attention has been paid to the role of image resizing operations." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "type": "text", + "content": "Resizing or rescaling refers to the process of changing the resolution of an image, while largely preserving its content for human or machine perception. There are several major reasons for using resizing: (1) The mini-batch gradient-based training scheme requires the same image resolution in a batch, (2) Resizing can help to reduce computational complexity, making it easier and faster to train" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6877" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 288, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 288, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 288, + 156 + ], + "type": "text", + "content": "and inference neural networks, (3) Smaller images consume lower memory footprint, enabling stable training of large models like Transformers with larger batch-size, (4) Resizing contributes to improving model generalization and robustness by reducing overfitting to specific image size and scales, making the models more flexible and applicable to real-world scenarios." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 158, + 287, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 158, + 287, + 266 + ], + "spans": [ + { + "bbox": [ + 46, + 158, + 287, + 266 + ], + "type": "text", + "content": "Moreover, resizing is an integral component of remote inference frameworks. Typically, to maintain the bandwidth efficiency of the communication network, before sending an image to the inference server, a thumbnail generator downscales the image to a fixed resolution (e.g. 480p). The thumbnail generator can be located on the client side (e.g. smart phone), or it can be part of a cloud storage system. This means that in most cases the inference server does not have access to the original image." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 269, + 288, + 520 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 269, + 288, + 520 + ], + "spans": [ + { + "bbox": [ + 46, + 269, + 288, + 520 + ], + "type": "text", + "content": "Basic resizing functions such as nearest-neighbor or bilinear interpolation have long been the go-to options with little to no deliberate consideration in most training software. While these simple methods offer greater simplicity and efficiency, they are not optimized for specific computer vision tasks and may lead to the loss of important visual features or details, which can, sometimes, result in significant performance degradation [29, 45]. To overcome this limitation, researchers have proposed learned resizers (or downsamplers) [3, 45] that leverage the deep neural networks to learn image resizing directly from data, yielding improved performance on several tasks. However, one of the main challenges with these learned resizers is that they often require a large number of parameters, and high computational overhead during training and inference. Note that this is specifically a bottleneck in remote inference where the resize (a.k.a thumbnail generator) is not in the inference server, and may have limited computational resources to run a heavy neural net resolver. Additionally, less-bounded resizers can sometimes be difficult to transfer to new tasks or datasets due to their excessive model capability." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 522, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 522, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 522, + 288, + 714 + ], + "type": "text", + "content": "In this paper, we introduce an incredibly lightweight learned resizer, which we call MULLER, that operates on multilayer Laplacian decomposition of images (see Fig. 2). Our method requires very few parameters and FLOPs, and does not incur any extra training cost, outperforming existing methods in terms of computational efficiency, parameter efficiency, and transferability. We show that it is the ability-to-learn that makes a better resizer, but not the capacity of the resizer - our MULLER resizer only learns four parameters and is more effective than previous complex ones using deep residual blocks [45]. We also demonstrate that our method can be used as a drop-in replacement for off-the-shelf resizing functions on several vision tasks, including classification, object detection and segmentation, and image quality assessment, resulting in significant performance improvements without any extra cost. As shown in Fig. 1," + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "text", + "content": "for example, training with the MULLER responder achieves up to " + }, + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "0.6\\%" + }, + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "text", + "content": " performance gain, using a state-of-the-art backbone MaxViT [50] as the testbed. Our contributions are:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 306, + 116, + 545, + 255 + ], + "type": "list", + "angle": 0, + "index": 8, + "blocks": [ + { + "bbox": [ + 306, + 116, + 545, + 152 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 116, + 545, + 152 + ], + "spans": [ + { + "bbox": [ + 306, + 116, + 545, + 152 + ], + "type": "text", + "content": "- We propose a surprisingly simple and lightweight resolver, that can be used as a drop-in replacement for off-the-shelf resizing functions like bilinear resizing." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 156, + 545, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 156, + 545, + 205 + ], + "spans": [ + { + "bbox": [ + 306, + 156, + 545, + 205 + ], + "type": "text", + "content": "- We demonstrate its applications to multiple computer vision tasks, including image classification, object detection and segmentation, and image quality assessment, showing superior performance over existing approaches." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 208, + 545, + 255 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 208, + 545, + 255 + ], + "spans": [ + { + "bbox": [ + 306, + 208, + 545, + 255 + ], + "type": "text", + "content": "- Extensive ablation studies, analysis, and visualization results are provided to show the robustness and generalization of the proposed resizer for various model scales, benchmarks, and tasks." + } + ] + } + ], + "index": 7 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 274, + 392, + 288 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 274, + 392, + 288 + ], + "spans": [ + { + "bbox": [ + 306, + 274, + 392, + 288 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 295, + 545, + 402 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 295, + 545, + 402 + ], + "spans": [ + { + "bbox": [ + 304, + 295, + 545, + 402 + ], + "type": "text", + "content": "Resizing in vision. Resizing is a crucial preprocessing step to train deep learning vision models. Due to their simplicity, efficiency and availability, nearest-neighbor and bilinear interpolations are the most widely used resizing methods in both training, inference, and serving. These simple approaches, however, can suffer from detail loss and artifacts, and the degraded image quality might hamper the performance of downstream visual recognition tasks, especially when the resizing factor is large." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 403, + 545, + 545 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 403, + 545, + 545 + ], + "spans": [ + { + "bbox": [ + 304, + 403, + 545, + 545 + ], + "type": "text", + "content": "Some recent works have explored to use learning-based methods for image downscaling to enhance the desired content in the resized images from training data [3,4,20,32,45, 61]. For example, the authors of [3,4] proposed a residual CNN module for downscaling, and jointly trained it with an image compression network to generate \"compression-friendly\" representations. [45] introduced a CNN-based learned resizer for various computer vision tasks, including image classification and image quality assessment. Similarly, the idea of learned rescaling has been applied to other computer vision applications [20, 32, 57, 61], showing improved performance in detection and recognition." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 546, + 545, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 546, + 545, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 546, + 545, + 665 + ], + "type": "text", + "content": "Image processing for machine vision. Image processing or enhancement problems such as super-resolution [19, 37], denoising [59], and deblurring [48, 49] have been longstanding challenges in computer vision. Recent works have focused on building larger-scale, diverse benchmarks, exploring novel model architectures, and improving training techniques. These works aim to produce visually pleasing outputs, often measured by conventional metrics like PSNR or SSIM [54], or through human evaluations, without considering downstream recognition performance of the output." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 666, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 666, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 666, + 545, + 713 + ], + "type": "text", + "content": "There exists a number of works relating image processing to image recognition performance, or machine-oriented image processing. Some works [17, 18, 34, 60] use image recognition accuracy as supplementary metrics besides" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "6878" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 82, + 69, + 500, + 188 + ], + "blocks": [ + { + "bbox": [ + 82, + 69, + 500, + 188 + ], + "lines": [ + { + "bbox": [ + 82, + 69, + 500, + 188 + ], + "spans": [ + { + "bbox": [ + 82, + 69, + 500, + 188 + ], + "type": "image", + "image_path": "90ccee828a535faba6416e26bc767b0ff615fb739efd224647c3cfd340377fd3.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 195, + 547, + 232 + ], + "lines": [ + { + "bbox": [ + 46, + 195, + 547, + 232 + ], + "spans": [ + { + "bbox": [ + 46, + 195, + 547, + 232 + ], + "type": "text", + "content": "Figure 2. The architecture of the proposed multilayer Laplacian resizer (MULLER). The resizer decomposes the input image into multiple layers of Laplacian residuals and then adds them back to the default resized image. The MULLER resizer is jointly trained with the downstream recognition model." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 247, + 289, + 439 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 247, + 289, + 439 + ], + "spans": [ + { + "bbox": [ + 46, + 247, + 289, + 439 + ], + "type": "text", + "content": "visual quality metrics to evaluate the performance of image restoration models. Towards recognition-aware training, [10] proposed to train super-resolution using object detection loss and show promising results over conventional methods. Other works [39, 42] introduce pre-editing networks before image compression to improve compression efficiency without sacrificing classification accuracy. Recently, Liu et al. [26] developed an approach to train the processing models under the objective of image recognition accuracy, and investigated the efficacy of popular preprocessing operations such as super-resolution, denoising, and JPEG-deblocking on improving recognition performance. More similar studies [16, 22, 23, 36] have been conducted to jointly train a processing model like denoising, dehazing, face reconstruction, together with recognition model to achieve better image processing for recognition quality." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 451, + 164, + 464 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 451, + 164, + 464 + ], + "spans": [ + { + "bbox": [ + 47, + 451, + 164, + 464 + ], + "type": "text", + "content": "3. Proposed Approach" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 472, + 287, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 472, + 287, + 651 + ], + "spans": [ + { + "bbox": [ + 46, + 472, + 287, + 651 + ], + "type": "text", + "content": "In this section, we introduce our proposed multilayer Laplacian resizer (MULLER, overviewed in Fig. 2), and discuss how we employ it for training several popular vision tasks. Unlike previous proposed resizers [3, 45], we aim to keep the computational cost of the model as low as possible such that it can replace existing resizers (e.g., bilinear) without extra cost, but also there is a notable performance gain. Our proposed approach is different in that (1) it is orders of magnitude faster, hence more scalable (to large image size), (2) it only has a handful of parameters which allows for better generalization, (3) it adds almost no extra training cost to the system. We show that with learning merely a couple of parameters, training with an added resizing module performs as effective as having a heavy downscaling network with several thousand parameter counts." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 659, + 138, + 671 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 659, + 138, + 671 + ], + "spans": [ + { + "bbox": [ + 47, + 659, + 138, + 671 + ], + "type": "text", + "content": "3.1. Resizer Model" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 59, + 678, + 280, + 691 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 678, + 280, + 691 + ], + "spans": [ + { + "bbox": [ + 59, + 678, + 280, + 691 + ], + "type": "text", + "content": "Image resizing models can be generally formulated as:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 108, + 700, + 287, + 715 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 108, + 700, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 108, + 700, + 287, + 715 + ], + "type": "interline_equation", + "content": "\\mathbf {y} = \\mathbf {F} _ {2} \\left(\\mathbf {R} \\left(\\mathbf {F} _ {1} (\\mathbf {x}); h ^ {\\prime}, w ^ {\\prime}\\right)\\right), \\tag {1}", + "image_path": "9258a4ddc33534f0b3fe7a8a19f10a33731798b092ce8304beb6cb62ef976570.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "spans": [ + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "inline_equation", + "content": "\\mathbf{R}" + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "content": " maps the input image " + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "content": " of size " + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "inline_equation", + "content": "h\\times w" + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "content": " to an output image of size " + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "inline_equation", + "content": "h^{\\prime}\\times w^{\\prime}" + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "content": " by computing the pixel values at the target spatial locations. " + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_1" + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_2" + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "content": " denote optional pre- and post-filtering operations. Typically, " + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_1" + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_2" + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "content": " can be identity functions, and " + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "inline_equation", + "content": "\\mathbf{R}" + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "content": " is chosen as a simple interpolation method like nearest-neighbor, bilinear, or bicubic. To learn more powerful resizing, learned resize has been proposed [3,4,45] by applying a base resizer on intermediate neural activations, wherein " + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_1" + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_2" + }, + { + "bbox": [ + 304, + 247, + 545, + 415 + ], + "type": "text", + "content": " are two designed CNNs applied at the original and output resolutions, respectively. Despite showing promising performance, however, these resize typically suffer from high computational complexity, and thus their net performance gain might be compromised in terms of the overall inference cost." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 420, + 462, + 433 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 420, + 462, + 433 + ], + "spans": [ + { + "bbox": [ + 305, + 420, + 462, + 433 + ], + "type": "text", + "content": "3.2. Proposed MULLER Resizer" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 438, + 545, + 547 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 438, + 545, + 547 + ], + "spans": [ + { + "bbox": [ + 304, + 438, + 545, + 547 + ], + "type": "text", + "content": "We are inspired by the observations that these different learned resize, if properly regularized, will often learn to enhance edges, details, or sharpness of the image to benefit downstream tasks [3, 4]. To this end, we present to date, the simplest learned resizing model, using multilayer Laplacian decomposition, that is able to achieve 'bandpassed' detail and texture manipulation with only a handful of learnable parameters. Fig. 2 shows the architecture of the proposed MULLER resize. MULLER has the following form:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 310, + 552, + 545, + 590 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 552, + 545, + 590 + ], + "spans": [ + { + "bbox": [ + 310, + 552, + 545, + 590 + ], + "type": "interline_equation", + "content": "\\mathbf {z} = \\underbrace {\\mathbf {R} (\\mathbf {x})} _ {\\text {B a s e i m a g e}} + \\sum_ {\\ell = 1} ^ {k} \\underbrace {\\sigma \\left(\\alpha_ {\\ell} \\left(\\mathbf {R} \\left(\\left(\\mathbf {W} _ {\\ell} - \\mathbf {W} _ {\\ell + 1}\\right) \\mathbf {x}\\right) + \\beta_ {\\ell}\\right)\\right)} _ {\\text {E n h a n c e d d e t a i l s i n e a c h s u b b a n d}}, \\tag {2}", + "image_path": "eddf215409a1679acc23313bc516bdc010952427ae8b10a25500518761c401cc.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "inline_equation", + "content": "\\mathbf{R}" + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "text", + "content": " denotes the base resizer (e.g. bilinear) and " + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{W}_1, \\mathbf{W}_2, \\dots, \\mathbf{W}_k\\}" + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "text", + "content": " represents the low-pass filter basis. We define " + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "inline_equation", + "content": "\\mathbf{W}_{\\ell}" + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "text", + "content": " as a positive row-stochastic matrix [27] of size " + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "inline_equation", + "content": "n \\times n" + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "text", + "content": ", with " + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "text", + "content": " representing the number of pixels in the vectorized input image " + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "text", + "content": ". Note that we assume " + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "inline_equation", + "content": "\\mathbf{W}_{k+1} = \\mathbf{I}" + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "inline_equation", + "content": "\\mathbf{I}" + }, + { + "bbox": [ + 304, + 594, + 545, + 689 + ], + "type": "text", + "content": " is the identity matrix. Each layer in Eq. (2) (see Fig. 2) uses a difference of the filters to decompose the image into different detail layers (bandpass filtering)." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "content": "Without loss of generality, we choose the Gaussian kernel as our base filter, and generate the filter bank by an iter-" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6879" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "spans": [ + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "text", + "content": "ative application of the same base filter as " + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "inline_equation", + "content": "\\mathbf{W}_{\\ell} = \\mathbf{W}^{k - \\ell +1}" + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "inline_equation", + "content": "\\mathbf{W}" + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "text", + "content": " being a Gaussian filter with standard deviation 1. Note that the iterative application of the low-pass filter results in a smoother image. The filtered subband image " + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "inline_equation", + "content": "(\\mathbf{W}_{\\ell} - \\mathbf{W}_{\\ell +1})\\mathbf{x}" + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "text", + "content": " in brach " + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "inline_equation", + "content": "\\ell" + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "text", + "content": " is fed into the base resizer to produce the target resolution layer. We add trainable scaling and bias parameters " + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "inline_equation", + "content": "(\\alpha_{\\ell},\\beta_{\\ell})" + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "text", + "content": " per layer to modulate and shift the resized response. Then, a nonlinearity function " + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "text", + "content": " (e.g., tanh) is applied on the resulting image layer, and finally the output is added to the base resized image. Note that the scaling factor " + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "inline_equation", + "content": "\\alpha_{\\ell}" + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "text", + "content": " controls the amount of detail boosted or suppressed in layer " + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "text", + "content": " of the resizer, and the bias parameter " + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "inline_equation", + "content": "\\beta_{\\ell}" + }, + { + "bbox": [ + 46, + 71, + 289, + 227 + ], + "type": "text", + "content": " controls the mean shift." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 228, + 289, + 348 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 228, + 289, + 348 + ], + "spans": [ + { + "bbox": [ + 46, + 228, + 289, + 348 + ], + "type": "text", + "content": "It is worth pointing out that in this framework, only the scalar and the bias values in the residual layers are trainable, meaning that for " + }, + { + "bbox": [ + 46, + 228, + 289, + 348 + ], + "type": "inline_equation", + "content": "k = 3" + }, + { + "bbox": [ + 46, + 228, + 289, + 348 + ], + "type": "text", + "content": ", there are only six trainable parameters, and the overall computational cost is only applying 4 bilinear resizers and 3 Gaussian filters. Note that the term \"Laplacian\" refers to an interpretation of the filtering structure in Fig. 2 that can be written as a summation of Laplacian operators, namely " + }, + { + "bbox": [ + 46, + 228, + 289, + 348 + ], + "type": "inline_equation", + "content": "\\mathbf{L}_{\\ell} = \\mathbf{I} - \\mathbf{W}_{\\ell}" + }, + { + "bbox": [ + 46, + 228, + 289, + 348 + ], + "type": "text", + "content": ". More explicitly, for a linear activation, the resulting image " + }, + { + "bbox": [ + 46, + 228, + 289, + 348 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 46, + 228, + 289, + 348 + ], + "type": "text", + "content": " can be expressed as a Laplacian form [43]:" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 57, + 355, + 287, + 369 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 355, + 287, + 369 + ], + "spans": [ + { + "bbox": [ + 57, + 355, + 287, + 369 + ], + "type": "interline_equation", + "content": "\\mathbf {y} = \\gamma_ {0} \\mathbf {R} (\\mathbf {x}) + \\gamma_ {1} \\mathbf {R} (\\mathbf {L} _ {1} \\mathbf {x}) + \\dots + \\gamma_ {k} \\mathbf {R} (\\mathbf {L} _ {k} \\mathbf {x}) + \\delta , \\tag {3}", + "image_path": "f5438992e94bdd8b4d0fa6bf56f55406b89661aa0836b478283098d6115e244d.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 374, + 203, + 388 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 374, + 203, + 388 + ], + "spans": [ + { + "bbox": [ + 47, + 374, + 203, + 388 + ], + "type": "text", + "content": "3.3. Applications in Vision Tasks" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 393, + 289, + 561 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 393, + 289, + 561 + ], + "spans": [ + { + "bbox": [ + 46, + 393, + 289, + 561 + ], + "type": "text", + "content": "While theoretically the resizer can be a drop-in replacement of the default resizer anywhere in the data generation and machine learning pipeline, we mainly demonstrate its ability to learn more informative thumbnail images for downstream recognition and detection tasks, which account for most of the practical use cases. We showcase the impact of MULLER by jointly training it with the backbone, where the resizer takes a higher-resolution image from the data pipeline and downscales it to lower-size before feeding as the model inputs. Since the proposed resizer is strongly regularized by its design, it needs no extra intermediate loss to train. The resizer is also task agnostic as no specific changes are needed to train with it in any framework on any vision or even vision-language tasks." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 571, + 128, + 585 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 571, + 128, + 585 + ], + "spans": [ + { + "bbox": [ + 47, + 571, + 128, + 585 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 590, + 287, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 590, + 287, + 687 + ], + "spans": [ + { + "bbox": [ + 46, + 590, + 287, + 687 + ], + "type": "text", + "content": "We validate the performance of our proposed MULLER resizer on several competitive vision tasks on which resolution plays an important role on performance, including image classification, object detection and segmentation, and image quality assessment. In order to showcase the impact of MULLER, our main experiments include the state-of-the-art vision Transformer model MaxViT [50] as the baseline. We first demonstrate the performance of this baseline" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "type": "text", + "content": "model by co-training it with MULLER. Then, we show that MULLER can be effective with other backbones such as ResNet [11], MobileNet-v2 [35] and EfficientNet-B0 [46]. In all the experiments, we use 2 layers in MULLER with Gaussian kernel size 5 and standard deviation 1. We use Tensorflow's default resizing as the base resizing. More experimental details can be found in supplementary materials." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 166, + 544, + 178 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 166, + 544, + 178 + ], + "spans": [ + { + "bbox": [ + 305, + 166, + 544, + 178 + ], + "type": "text", + "content": "4.1. Main Experiments on ImageNet Classification" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 185, + 545, + 304 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 185, + 545, + 304 + ], + "spans": [ + { + "bbox": [ + 304, + 185, + 545, + 304 + ], + "type": "text", + "content": "We demonstrate the efficacy of the MULLER resizer on the standard, but most competitive ImageNet-1K classification task [15]. We take a top-performing vision Transformer, MaxViT [50], as the backbone model, and pre-train it on ImageNet-1K at " + }, + { + "bbox": [ + 304, + 185, + 545, + 304 + ], + "type": "inline_equation", + "content": "224 \\times 224" + }, + { + "bbox": [ + 304, + 185, + 545, + 304 + ], + "type": "text", + "content": " resolution for 300 epochs. Instead of directly fine-tuning at higher resolution (e.g., 384 or 512) like previous practices [8,9,24,50], we jointly fine-tune the backbone with the MULLER resizer plugged before the stem layers. We set input and output resolutions as 512 and 224 for MULLER in the ImageNet experiments." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 305, + 546, + 473 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 305, + 546, + 473 + ], + "spans": [ + { + "bbox": [ + 304, + 305, + 546, + 473 + ], + "type": "text", + "content": "ImageNet-1K. The main results on ImageNet-1K classification are shown in Tab. 1. Note that we include all the state-of-the-art models trained to their highest possible accuracy reported in the original papers. For better visualization, we draw the accuracy vs. FLOPs and accuracy vs. inference-latency scaling curves in Fig. 3, respectively. As may be seen, MaxViT powered by the MULLER resizer sets a new state-of-the-art top-1 accuracy " + }, + { + "bbox": [ + 304, + 305, + 546, + 473 + ], + "type": "inline_equation", + "content": "85.68\\%" + }, + { + "bbox": [ + 304, + 305, + 546, + 473 + ], + "type": "text", + "content": " with only 43.9B FLOPs among all the compared models trained at 224x224. MULLER improves at an average of 0.49 accuracy across the four MaxViT variants. In terms of actual inference time, MaxViT with MULLER exceeds among all the models trained at various resolution - equivalently, it can save " + }, + { + "bbox": [ + 304, + 305, + 546, + 473 + ], + "type": "inline_equation", + "content": "36\\%" + }, + { + "bbox": [ + 304, + 305, + 546, + 473 + ], + "type": "text", + "content": " latency to achieve " + }, + { + "bbox": [ + 304, + 305, + 546, + 473 + ], + "type": "inline_equation", + "content": "\\sim 85.7\\%" + }, + { + "bbox": [ + 304, + 305, + 546, + 473 + ], + "type": "text", + "content": " accuracy." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "spans": [ + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "text", + "content": "ImageNet-21K and JFT. To demonstrate the scaling properties of the MULLER resizer with respect to data size, in Tab. 2 we report the results of the models pre-trained on ImageNet-21K and JFT-300M [38], respectively. It can be seen that with ImageNet-21k pretraining, the finetuned MaxViT with MULLER" + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "inline_equation", + "content": "_{512 \\rightarrow 224}" + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "text", + "content": " gains " + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "inline_equation", + "content": "0.8\\%" + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "inline_equation", + "content": "0.6\\%" + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "inline_equation", + "content": "0.7\\%" + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "text", + "content": " accuracy over directly finetuning without resizer for B, L, and XL models, respectively. Similarly for JFT-300M pretraining, those numbers are " + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "inline_equation", + "content": "0.8\\%" + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "inline_equation", + "content": "0.7\\%" + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "inline_equation", + "content": "0.7\\%" + }, + { + "bbox": [ + 304, + 474, + 545, + 617 + ], + "type": "text", + "content": ". It indicates that when finetuning with MULLER, MaxViT scales consistently when data size increases from ImageNet-1k up to JFT-300M." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 618, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 618, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 618, + 545, + 714 + ], + "type": "text", + "content": "We further observe that for larger models and larger training sets, the backbone can benefit even more through seeing larger input images. Thus, we also report the performance of training with " + }, + { + "bbox": [ + 304, + 618, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathrm{MULLER}_{576\\rightarrow 288}" + }, + { + "bbox": [ + 304, + 618, + 545, + 714 + ], + "type": "text", + "content": ". We can see that it further boosts the performance by an average of " + }, + { + "bbox": [ + 304, + 618, + 545, + 714 + ], + "type": "inline_equation", + "content": "0.4\\sim 0.5\\%" + }, + { + "bbox": [ + 304, + 618, + 545, + 714 + ], + "type": "text", + "content": " across the board for both 21K and JFT. Remarkably, MaxViT-XL with " + }, + { + "bbox": [ + 304, + 618, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathrm{MULLER}_{576\\rightarrow 288}" + }, + { + "bbox": [ + 304, + 618, + 545, + 714 + ], + "type": "text", + "content": " achieves " + }, + { + "bbox": [ + 304, + 618, + 545, + 714 + ], + "type": "inline_equation", + "content": "89.16\\%" + }, + { + "bbox": [ + 304, + 618, + 545, + 714 + ], + "type": "text", + "content": " top-1 accuracy with only 162.9B FLOPs." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 46, + 693, + 287, + 715 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 693, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 693, + 287, + 715 + ], + "type": "text", + "content": "1Note that MULLER is not limited to downscaling, and in fact should the original image data be low resolution, it can learn to upscale as well." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6880" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 70, + 289, + 411 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 289, + 411 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 289, + 411 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 289, + 411 + ], + "type": "table", + "html": "
ModelEval sizeParamsFLOPsThr (img/s)IN-1K top-1 acc
EffNetV2-S [47]38424M8.8B666.683.9
EffNetV2-M [47]48055M24.0B280.785.1
ConvNeXt-T [25]22429M4.5B77482.1
ConvNeXt-S [25]22450M8.7B447.183.1
ConvNeXt-B [25]22489M15.4B292.183.8
ConvNeXt-L [25]224198M34.4B146.884.3
ViT-B/32 [9]38486M55.4B85.977.9
ViT-B/16 [9]384307M190.7B27.376.5
Swin-T [24]22429M4.5B755.281.3
Swin-S [24]22450M8.7B436.983.0
Swin-B [24]22488M15.4B278.183.5
CSwin-B [8]22423M4.3B70182.7
CSwin-B [8]22435M6.9B43783.6
CSwin-B [8]22478M15.0B25084.2
CoAtNet-0 [7]22425M4.2B52681.6
CoAtNet-1 [7]22425M4.2B33683.3
CoAtNet-2 [7]22475M15.7B247.784.1
CoAtNet-3 [7]224168M34.7B163.384.5
MaxViT-T22431M5.6B350.483.62
+MULLER512→22422431M5.63B349.683.95
MaxViT-S22469M11.7B242.584.45
+MULLER512→22422469M11.73B241.484.95
MaxViT-B224120M23.4B133.684.95
+MULLER512→224224120M23.43B133.085.58
MaxViT-L224212M43.9B99.485.17
+MULLER512→224224212M43.93B99.385.68
", + "image_path": "6f979b410b1fed5f0abda26c9ccd68a6f8ae4f3af751d1aa132fb87a3c07b0eb.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 419, + 287, + 504 + ], + "lines": [ + { + "bbox": [ + 46, + 419, + 287, + 504 + ], + "spans": [ + { + "bbox": [ + 46, + 419, + 287, + 504 + ], + "type": "text", + "content": "Table 1. Performance comparison under the ImageNet-1K setting. MULLER" + }, + { + "bbox": [ + 46, + 419, + 287, + 504 + ], + "type": "inline_equation", + "content": "_{\\mathrm{A} \\rightarrow \\mathrm{B}}" + }, + { + "bbox": [ + 46, + 419, + 287, + 504 + ], + "type": "text", + "content": " denote that MULLER resizes from A to B, where the backbone takes images of size B. FLOPs counts the total computation of the resolver and backbone. Throughput (Thr) is measured on a single V100 GPU with batch size 16, following [24,25,47]. " + }, + { + "bbox": [ + 46, + 419, + 287, + 504 + ], + "type": "inline_equation", + "content": "\\bullet" + }, + { + "bbox": [ + 46, + 419, + 287, + 504 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 419, + 287, + 504 + ], + "type": "inline_equation", + "content": "\\diamond" + }, + { + "bbox": [ + 46, + 419, + 287, + 504 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 419, + 287, + 504 + ], + "type": "inline_equation", + "content": "\\diamond" + }, + { + "bbox": [ + 46, + 419, + 287, + 504 + ], + "type": "text", + "content": " denote ConvNets, Transformers, and hybrid models, respectively." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 517, + 287, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 517, + 287, + 601 + ], + "spans": [ + { + "bbox": [ + 46, + 517, + 287, + 601 + ], + "type": "text", + "content": "We also examine the generalization of the resizer across different model variants. We found that the learned weights in MULLER are very close across different variants, and the transferring results are as effective as the original training. Detailed results are in the supplementary materials. Note that we present our generalization experiments across different backbones in the next section." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 610, + 167, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 610, + 167, + 623 + ], + "spans": [ + { + "bbox": [ + 47, + 610, + 167, + 623 + ], + "type": "text", + "content": "4.2. Different Backbones" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "content": "Main results. To explore the resizer beyond the MaxViT architecture, we selected some widely used backbones including ResNet-50 [11], EfficientNet-B0 [46], and MobileNetv2 [35]. Our results are presented in Tab. 3. We also make comparisons with the resizer of Talebi et al. [45]. We observed that the proposed resizer improves the performance of the baseline backbones consistently. Also compared to" + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 310, + 73, + 541, + 243 + ], + "blocks": [ + { + "bbox": [ + 310, + 73, + 541, + 243 + ], + "lines": [ + { + "bbox": [ + 310, + 73, + 541, + 243 + ], + "spans": [ + { + "bbox": [ + 310, + 73, + 541, + 243 + ], + "type": "image", + "image_path": "978247de0b4f8035fa63b6c7a95cf301ff15da7578d21d60bc27f360adfa9c59.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 311, + 248, + 542, + 422 + ], + "blocks": [ + { + "bbox": [ + 311, + 248, + 542, + 422 + ], + "lines": [ + { + "bbox": [ + 311, + 248, + 542, + 422 + ], + "spans": [ + { + "bbox": [ + 311, + 248, + 542, + 422 + ], + "type": "image", + "image_path": "d3d7c435ed39b86c6773f1fdc0ea9c12e76a14857b4ce25423ecffb23851c375.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 431, + 547, + 540 + ], + "lines": [ + { + "bbox": [ + 304, + 431, + 547, + 540 + ], + "spans": [ + { + "bbox": [ + 304, + 431, + 547, + 540 + ], + "type": "text", + "content": "Figure 3. Model FLOPs (top), and Inference Latency (bottom) performance comparison of state-of-the-art vision backbones on ImageNet-1K. We show that MaxViT trained with MULLER resizer yielded the best accuracy vs. computation and accuracy vs. inference-cost tradeoff. Note that top figure includes only " + }, + { + "bbox": [ + 304, + 431, + 547, + 540 + ], + "type": "inline_equation", + "content": "224 \\times 224" + }, + { + "bbox": [ + 304, + 431, + 547, + 540 + ], + "type": "text", + "content": " models whereas the bottom figures include the best possible performance curves among various training size. Inference time is calculated by the throughput in Tab. 1." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 555, + 545, + 614 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 555, + 545, + 614 + ], + "spans": [ + { + "bbox": [ + 304, + 555, + 545, + 614 + ], + "type": "text", + "content": "[46], MULLER requires a significantly lower number of FLOPs (two orders-of-magnitude), and in some cases such as MobileNet-v2 and EfficientNet-B0 it outperforms [45]. These results also indicate that MULLER improves over baseline resizers low the FLOPs regime as well." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 616, + 545, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 616, + 545, + 676 + ], + "spans": [ + { + "bbox": [ + 304, + 616, + 545, + 676 + ], + "type": "text", + "content": "Cross-model Generalization. In order to examine the generalizability of MULLER, we evaluate classification models with resizers that are trained with other backbones. To this end, we first present the learned resizer parameters for each backbone, and then discuss the classification performances." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "content": "Results in Tab. 4 represent the learned MULLER parameters (see Eq. 2) for each backbone model trained on ImageNet-1k. We observed that (1) performance of the clas" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "6881" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 47, + 69, + 289, + 473 + ], + "blocks": [ + { + "bbox": [ + 47, + 69, + 289, + 473 + ], + "lines": [ + { + "bbox": [ + 47, + 69, + 289, + 473 + ], + "spans": [ + { + "bbox": [ + 47, + 69, + 289, + 473 + ], + "type": "table", + "html": "
ModelEval sizeParamsFLOPsIN-1K top-1 acc.
21K-ptJFT-pt
BiT-R-101x3 [14]384388M204.6B84.4-
BiT-R-152x4 [14]480937M840.5B85.4-
EffNetV2-L [47]480121M53.0B86.8-
EffNetV2-XL [47]512208M94.0B87.3-
ConvNeXt-L [25]384198M101.0B87.5-
ConvNeXt-XL [25]384350M179.0B87.8-
NFNet-F4+ [2]512527M367B-89.20
ViT-B/16 [9]38487M55.5B84.0-
ViT-L/16 [9]384305M191.1B85.2
ViT-L/16 [9]512305M364B-87.76
ViT-H/14 [9]518632M1021B-88.55
HaloNet-H4 [52]51285M-85.8-
SwinV2-B [24]38488M-87.1-
SwinV2-L [24]384197M-87.7-
CvT-W24 [55]384277M193.2B87.7-
R+ViT-L/16 [9]384330M--87.12
CoAtNet-3 [7]384168M107.4B87.688.52
CoAtNet-3 [7]512168M214B87.988.81
CoAtNet-4 [7]512275M360.9B88.189.11
MaxViT-B224119M23.4B86.6387.05
+MULLER512→224224119M23.4B87.4087.82
+MULLER576→288288119M40.6B87.9288.39
MaxViT-L224212M43.9B86.8687.72
+MULLER512→224224212M43.9B87.4888.43
+MULLER576→288288212M73.4B87.9488.87
MaxViT-XL224475M97.8B87.2588.06
+MULLER512→224224475M97.8B87.9088.74
+MULLER576→288288475M162.9B88.3189.16
MaxViT-B512119M138.3B88.3888.82
MaxViT-L512212M245.2B88.4689.41
MaxViT-XL512475M535.2B88.7089.53
", + "image_path": "8eed22349c161fcf107b812a22329b20f7d2c211108814ebdef49148532e5a81.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "spans": [ + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "type": "text", + "content": "sification models are more sensitive to " + }, + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "type": "inline_equation", + "content": "\\alpha_{1}" + }, + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "type": "text", + "content": " than " + }, + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "type": "inline_equation", + "content": "\\alpha_{2}" + }, + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "type": "text", + "content": ", and (2) the learned bias values are relatively small, meaning the resizer does not significantly shift the mean of each residual image layer. Note that " + }, + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "type": "inline_equation", + "content": "|\\alpha_{\\ell}| > 1" + }, + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "type": "text", + "content": " means the image details represented by the " + }, + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "type": "inline_equation", + "content": "\\ell" + }, + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "type": "text", + "content": "-th layer are boosted, whereas " + }, + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "type": "inline_equation", + "content": "|\\alpha_{\\ell}| < 1" + }, + { + "bbox": [ + 46, + 567, + 287, + 640 + ], + "type": "text", + "content": " has the opposite effect." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 641, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 287, + 714 + ], + "type": "text", + "content": "To quantify generalizability of the resizer, we used the learned parameters in Tab. 4 to evaluate different backbones. As for different backbones, Tab. 5 shows that one model leads to classification performance that is in the average proximity of 0.15 from the best top-1 accuracy. We believe this can be explained by the fact that MULLER is a" + } + ] + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 328, + 69, + 526, + 196 + ], + "blocks": [ + { + "bbox": [ + 46, + 480, + 287, + 553 + ], + "lines": [ + { + "bbox": [ + 46, + 480, + 287, + 553 + ], + "spans": [ + { + "bbox": [ + 46, + 480, + 287, + 553 + ], + "type": "text", + "content": "Table 2. Performance comparison for large-scale data regimes: ImageNet-21K and JFT pretrained models. We report results using two different settings: " + }, + { + "bbox": [ + 46, + 480, + 287, + 553 + ], + "type": "inline_equation", + "content": "\\mathrm{MULLER}_{512\\rightarrow 224}" + }, + { + "bbox": [ + 46, + 480, + 287, + 553 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 480, + 287, + 553 + ], + "type": "inline_equation", + "content": "\\mathrm{MULLER}_{576\\rightarrow 288}" + }, + { + "bbox": [ + 46, + 480, + 287, + 553 + ], + "type": "text", + "content": " respectively, as we observe that on larger models and larger training sets, the backbone benefits more by seeing larger inputs." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 328, + 69, + 526, + 196 + ], + "lines": [ + { + "bbox": [ + 328, + 69, + 526, + 196 + ], + "spans": [ + { + "bbox": [ + 328, + 69, + 526, + 196 + ], + "type": "table", + "html": "
ModelSizeFLOPstop-1 acc.
EffNet-B0 [46]2240.39B77.1
+ [45]512→2242242.63B77.9
+MULLER512→2242240.42B78.2
MobileNet-v2 [35]2240.60B70.5
+ [45]512→2242242.84B71.5
+MULLER512→2242240.63B71.8
ResNet-50 [11]2246.97B75.3
+ [45]512→2242249.33B76.2
+MULLER512→2242247.0B76.2
", + "image_path": "1c6db74d6dad84e10fe143a7a7cfc0a6185216a806349f87bd13405a12576ba9.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 315, + 239, + 538, + 293 + ], + "blocks": [ + { + "bbox": [ + 305, + 203, + 545, + 228 + ], + "lines": [ + { + "bbox": [ + 305, + 203, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 305, + 203, + 545, + 228 + ], + "type": "text", + "content": "Table 3. Performance comparison under ImageNet-1K setting with different backbones." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 315, + 239, + 538, + 293 + ], + "lines": [ + { + "bbox": [ + 315, + 239, + 538, + 293 + ], + "spans": [ + { + "bbox": [ + 315, + 239, + 538, + 293 + ], + "type": "table", + "html": "
Modelα1β1α2β2
EffNet-B0 [46]1.7150.088-8.410.001
MobileNet-v2 [35]1.4800.174-5.25-0.058
ResNet-50 [11]1.892-0.014-11.2950.003
", + "image_path": "4eeb138f1280423fde695a4de0db5459d8e234a9622777746fe389c12318aee3.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 310, + 337, + 543, + 392 + ], + "blocks": [ + { + "bbox": [ + 305, + 301, + 545, + 326 + ], + "lines": [ + { + "bbox": [ + 305, + 301, + 545, + 326 + ], + "spans": [ + { + "bbox": [ + 305, + 301, + 545, + 326 + ], + "type": "text", + "content": "Table 4. The learned MULLER parameters for different backbone models train on ImageNet-1k." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 310, + 337, + 543, + 392 + ], + "lines": [ + { + "bbox": [ + 310, + 337, + 543, + 392 + ], + "spans": [ + { + "bbox": [ + 310, + 337, + 543, + 392 + ], + "type": "table", + "html": "
ModelEffNet-B0MobileNet-v2ResNet-50
MULLEREffNet78.271.675.9
MULLERMobileNet78.071.876.0
MULLERResNet78.171.776.2
", + "image_path": "c86241d93a9ba2539409867ff62b6de7b59b5e12d3bd20addf42852956bfb8cd.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 399, + 545, + 422 + ], + "lines": [ + { + "bbox": [ + 305, + 399, + 545, + 422 + ], + "spans": [ + { + "bbox": [ + 305, + 399, + 545, + 422 + ], + "type": "text", + "content": "Table 5. Cross-model validation of the MULLER resolver for ImageNet-1K on different backbones." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 436, + 545, + 472 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 436, + 545, + 472 + ], + "spans": [ + { + "bbox": [ + 304, + 436, + 545, + 472 + ], + "type": "text", + "content": "constrained model with only 4 trainable parameters. Also, it is important to highlight that in contrast to the resizer in [45], MULLER does not require fine-tuning." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 472, + 546, + 591 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 472, + 546, + 591 + ], + "spans": [ + { + "bbox": [ + 304, + 472, + 546, + 591 + ], + "type": "text", + "content": "Impact of Aliasing. It has been shown that aliasing may impact the performance of some deep vision models [29,51]. It is worth mentioning that the results presented in this section are based on anti-aliased images. More specifically, we used the AREA downscaling method in TensorFlow to produce " + }, + { + "bbox": [ + 304, + 472, + 546, + 591 + ], + "type": "inline_equation", + "content": "512^{2}" + }, + { + "bbox": [ + 304, + 472, + 546, + 591 + ], + "type": "text", + "content": " inputs to MULLER. We observed that while removing anti-aliasing does not hamper the overall performance gain obtained by MULLER, the learned parameters may differ from Tab. 4. We will present our results without anti-aliasing in the supplementary material." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 599, + 415, + 610 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 599, + 415, + 610 + ], + "spans": [ + { + "bbox": [ + 306, + 599, + 415, + 610 + ], + "type": "text", + "content": "4.3. Downstream tasks" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 617, + 545, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 545, + 700 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 545, + 700 + ], + "type": "text", + "content": "Object Detection and Instance Segmentation. We evaluated the performance of MULLER on COCO2017 [21] for object bounding box detection and instance segmentation tasks with a two-stage cascaded Mask-RCNN framework [31]. We warm start the MaxViT backbone using checkpoints pretrained on ImageNet-1K, then finetune the whole model including the resizing on COCO." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 318, + 702, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 318, + 702, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 318, + 702, + 545, + 714 + ], + "type": "text", + "content": "Tab. 6 summarizes the object detection and instance seg" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6882" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 47, + 70, + 289, + 327 + ], + "blocks": [ + { + "bbox": [ + 47, + 70, + 289, + 327 + ], + "lines": [ + { + "bbox": [ + 47, + 70, + 289, + 327 + ], + "spans": [ + { + "bbox": [ + 47, + 70, + 289, + 327 + ], + "type": "table", + "html": "
BackboneResolutionAP\\( AP_{50} \\)\\( AP_{75} \\)\\( AP^m \\)\\( AP_{50}^m \\)\\( AP_{75}^m \\)FLOPs
•ResNet-50 [11]1280×80046.364.350.540.161.743.4739B
•X101-32 [56]1280×80048.166.552.441.663.945.2819B
•X101-64 [56]1280×80048.366.452.341.764.045.1972B
•ConvNeXt-T [25]1280×80050.469.154.843.766.547.3741B
•ConvNeXt-S [25]1280×80051.970.856.545.068.449.1827B
•ConvNeXt-B [25]1280×80052.771.357.245.668.949.5964B
○Swin-T [24]1280×80050.469.254.743.766.647.3745B
○Swin-S [24]1280×80051.970.756.345.068.248.8838B
○Swin-B [24]1280×80051.970.556.445.068.148.9982B
○UViT-T [6]896×89651.170.456.243.667.747.2613B
○UViT-S [6]896×89651.470.856.244.168.248.0744B
○UViT-B [6]896×89652.572.057.644.368.748.3975B
○MaxViT-T640×64049.969.954.642.766.646.4379B
○+MULR896→640640×64050.570.755.043.167.046.7379B
○MaxViT-S640×64050.570.255.343.367.346.8432B
○+MULR896→640640×64050.870.455.543.567.747.1432B
○MaxViT-B640×64051.671.356.144.168.547.7543B
○+MULR896→640640×64052.371.557.044.768.948.7543B
○MaxViT-T896×89652.171.956.844.669.148.4475B
○MaxViT-S896×89653.172.558.145.469.849.5595B
○MaxViT-B896×89653.472.958.145.770.350.0856B
", + "image_path": "690f887d496060f1af67a9b4e1d04c9f71e96ea2143879ada47ab4fc4648d04d.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 397, + 287, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 397, + 287, + 529 + ], + "spans": [ + { + "bbox": [ + 46, + 397, + 287, + 529 + ], + "type": "text", + "content": "mentation results comparing state-of-the-art ConvNets and vision Transformers. AP and " + }, + { + "bbox": [ + 46, + 397, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\mathrm{AP}^m" + }, + { + "bbox": [ + 46, + 397, + 287, + 529 + ], + "type": "text", + "content": " denote box and mask average precision. We report the train and evaluation resolutions as well as their corresponding FLOPs as reference for model complexity. It may be seen that MaxViT suffers from noticeable performance drop if training resolution is lower. However, we observed that training with the MULLER resized can further improve the performance across the board. Specifically, on MaxViT-B at " + }, + { + "bbox": [ + 46, + 397, + 287, + 529 + ], + "type": "inline_equation", + "content": "640 \\times 640" + }, + { + "bbox": [ + 46, + 397, + 287, + 529 + ], + "type": "text", + "content": ", finetuning with MULLER gains 0.7 AP and 0.6 mask AP on the COCO validation set without any FLOPs overhead." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 531, + 287, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 531, + 287, + 640 + ], + "spans": [ + { + "bbox": [ + 46, + 531, + 287, + 640 + ], + "type": "text", + "content": "Image Quality Assessment. We base our experiment on the AVA dataset [28], which includes 250K images rated by amateur photographers. Each image in the dataset is associated with a histogram of ratings from an average of 200 raters. Image quality and aesthetic assessment is a task that is sensitive to downscaling [13], as downscaling may negatively impact visual quality attributes such as sharpness. We use the Earth Mover's Distance (EMD) as our training loss, similar to previous work of [44]." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "type": "text", + "content": "Our results are shown in Tab. 7. We report the Pearson linear correlation coefficient (PLCC) of the predicted and ground truth mean ratings as our evaluation metric. As can be seen, the proposed resizer improves the performance of MaxViT beyond the existing methods such as MUSIQ [13]. Note that in contrast to MUSIQ which uses multi-scale in" + } + ] + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 331, + 70, + 524, + 209 + ], + "blocks": [ + { + "bbox": [ + 46, + 335, + 288, + 371 + ], + "lines": [ + { + "bbox": [ + 46, + 335, + 288, + 371 + ], + "spans": [ + { + "bbox": [ + 46, + 335, + 288, + 371 + ], + "type": "text", + "content": "Table 6. Comparison of two-stage object detection and instance segmentation on COCO2017. All models are pretrained on ImageNet-1K." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 331, + 70, + 524, + 209 + ], + "lines": [ + { + "bbox": [ + 331, + 70, + 524, + 209 + ], + "spans": [ + { + "bbox": [ + 331, + 70, + 524, + 209 + ], + "type": "table", + "html": "
ModelSizeParamsPLCC↑
•NIMA [44]22456M0.636
•+ [45]512→22422456M0.680
•EffNet-B0 [46]2245.3M0.642
•+ [45]512→2242245.3M0.650
•AFDC [5]22444.5M0.671
○ViT-S/32 [13]38422M0.665
○ViT-B/32 [13]38488M0.664
○MUSIQ [13]224~51227M0.720
◇MaxViT-T22431M0.707
◇+MULLER512→22422431M0.729
", + "image_path": "45d292995585b974ae6956b5269b79b88dc47e62382eb6db872bf7a914bbefd6.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 328, + 264, + 525, + 379 + ], + "blocks": [ + { + "bbox": [ + 305, + 216, + 545, + 251 + ], + "lines": [ + { + "bbox": [ + 305, + 216, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 305, + 216, + 545, + 251 + ], + "type": "text", + "content": "Table 7. Image aesthetic assessment results on the AVA benchmark [28]. PLCC represents the Pearson's linear correlation coefficient." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 328, + 264, + 525, + 379 + ], + "lines": [ + { + "bbox": [ + 328, + 264, + 525, + 379 + ], + "spans": [ + { + "bbox": [ + 328, + 264, + 525, + 379 + ], + "type": "table", + "html": "
nlayersksizestdTop-1 AccFLOPs
251.085.5824.23B
351.085.5224.24B
451.085.5024.25B
651.085.5924.27B
231.085.4824.23B
271.085.5724.24B
251.585.5624.24B
252.085.5324.24B
", + "image_path": "614a192052e52b036b5bc3b16c03482abeb656c1c41a272f2cb9dafa529281c4.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 321, + 411, + 531, + 513 + ], + "blocks": [ + { + "bbox": [ + 324, + 387, + 527, + 399 + ], + "lines": [ + { + "bbox": [ + 324, + 387, + 527, + 399 + ], + "spans": [ + { + "bbox": [ + 324, + 387, + 527, + 399 + ], + "type": "text", + "content": "Table 8. Hyperparameter sweep for MULLER." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 321, + 411, + 531, + 513 + ], + "lines": [ + { + "bbox": [ + 321, + 411, + 531, + 513 + ], + "spans": [ + { + "bbox": [ + 321, + 411, + 531, + 513 + ], + "type": "table", + "html": "
input sizeoutput sizeTop-1 AccFLOPs
38422485.4524.22B
51222485.5824.23B
76822485.5624.26B
51238486.4274.25B
76838486.4474.28B
76851286.68138.57B
102451286.67138.60B
", + "image_path": "0c48dddca52a4028d110833cceb867775a55f080b942e713a4c40e745be67485.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 521, + 545, + 557 + ], + "lines": [ + { + "bbox": [ + 305, + 521, + 545, + 557 + ], + "spans": [ + { + "bbox": [ + 305, + 521, + 545, + 557 + ], + "type": "text", + "content": "Table 9. Effects of input and output size for MULLER using MaxViT-Base as test backkBone. Note that the output size is the image size seen by the backbone." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 305, + 578, + 545, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 578, + 545, + 604 + ], + "spans": [ + { + "bbox": [ + 305, + 578, + 545, + 604 + ], + "type": "text", + "content": "put augmentations, MULLER+MaxViT only requires a single low-resolution input from the resizing." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 611, + 370, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 611, + 370, + 623 + ], + "spans": [ + { + "bbox": [ + 306, + 611, + 370, + 623 + ], + "type": "text", + "content": "4.4. Ablation" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "text", + "content": "Hyperparameters. There are three hyperparameters in the design of MULLER: " + }, + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\{k, hsize, stddev\\}" + }, + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "text", + "content": ", which denote the number of layers, the kernel size of the Gaussian filters " + }, + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{W}_1, \\mathbf{W}_2, \\dots, \\mathbf{W}_k\\}" + }, + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "text", + "content": ", and the standard deviation of the Gaussian filters. To understand the effect of these hyperparameters, we conduct an ablation study. As shown in Tab. 8, we found that MULLER is quite insensitive to the selection" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6883" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 66, + 70, + 202, + 176 + ], + "blocks": [ + { + "bbox": [ + 66, + 70, + 202, + 176 + ], + "lines": [ + { + "bbox": [ + 66, + 70, + 202, + 176 + ], + "spans": [ + { + "bbox": [ + 66, + 70, + 202, + 176 + ], + "type": "image", + "image_path": "8b9c5c1238018d1e12adef7cddd12a96661bfe1f16778e243d0d080f96e67335.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 66, + 176, + 203, + 281 + ], + "blocks": [ + { + "bbox": [ + 66, + 176, + 203, + 281 + ], + "lines": [ + { + "bbox": [ + 66, + 176, + 203, + 281 + ], + "spans": [ + { + "bbox": [ + 66, + 176, + 203, + 281 + ], + "type": "image", + "image_path": "a7b962ec181b2d97062e6d654a552df3ac8e697c6595e933086305a40939e6d6.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 109, + 282, + 153, + 293 + ], + "lines": [ + { + "bbox": [ + 109, + 282, + 153, + 293 + ], + "spans": [ + { + "bbox": [ + 109, + 282, + 153, + 293 + ], + "type": "text", + "content": "(a) Original" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 205, + 70, + 310, + 175 + ], + "blocks": [ + { + "bbox": [ + 205, + 70, + 310, + 175 + ], + "lines": [ + { + "bbox": [ + 205, + 70, + 310, + 175 + ], + "spans": [ + { + "bbox": [ + 205, + 70, + 310, + 175 + ], + "type": "image", + "image_path": "e786e0e5496ae7cca9e8ea764837dfc4dd73d1e036eac00bdc68d5641c302f1c.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 205, + 176, + 310, + 281 + ], + "blocks": [ + { + "bbox": [ + 205, + 176, + 310, + 281 + ], + "lines": [ + { + "bbox": [ + 205, + 176, + 310, + 281 + ], + "spans": [ + { + "bbox": [ + 205, + 176, + 310, + 281 + ], + "type": "image", + "image_path": "8134e7efcf639f24606e45fc147c20a6f0440d32eb38c749d40319061779e355.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 227, + 282, + 294, + 292 + ], + "lines": [ + { + "bbox": [ + 227, + 282, + 294, + 292 + ], + "spans": [ + { + "bbox": [ + 227, + 282, + 294, + 292 + ], + "type": "text", + "content": "(b) Default resizer" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 312, + 70, + 417, + 175 + ], + "blocks": [ + { + "bbox": [ + 312, + 70, + 417, + 175 + ], + "lines": [ + { + "bbox": [ + 312, + 70, + 417, + 175 + ], + "spans": [ + { + "bbox": [ + 312, + 70, + 417, + 175 + ], + "type": "image", + "image_path": "c011fae887eaeb90b297ea9a748ddde12c0cdb3edacdf5d84d7aa4f09007512c.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 312, + 176, + 417, + 281 + ], + "blocks": [ + { + "bbox": [ + 312, + 176, + 417, + 281 + ], + "lines": [ + { + "bbox": [ + 312, + 176, + 417, + 281 + ], + "spans": [ + { + "bbox": [ + 312, + 176, + 417, + 281 + ], + "type": "image", + "image_path": "1dbce26ee9e4edf0eddc9af9cc18ba6b6759ba29f36ba6d3ff51c8c3b1b77e1a.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 330, + 282, + 400, + 292 + ], + "lines": [ + { + "bbox": [ + 330, + 282, + 400, + 292 + ], + "spans": [ + { + "bbox": [ + 330, + 282, + 400, + 292 + ], + "type": "text", + "content": "(c) Learned resizer" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 295, + 545, + 319 + ], + "lines": [ + { + "bbox": [ + 46, + 295, + 545, + 319 + ], + "spans": [ + { + "bbox": [ + 46, + 295, + 545, + 319 + ], + "type": "text", + "content": "Figure 4. Visualizations of the learned MULLER resizer for ResNet-50. Here the default resizer is an (anti-aliased) AREA resizer in Tensorflow. (d) shows the difference of the learned and the default resizers." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 419, + 70, + 525, + 175 + ], + "blocks": [ + { + "bbox": [ + 419, + 70, + 525, + 175 + ], + "lines": [ + { + "bbox": [ + 419, + 70, + 525, + 175 + ], + "spans": [ + { + "bbox": [ + 419, + 70, + 525, + 175 + ], + "type": "image", + "image_path": "672abccec551ea0d900c31bcd304faf54d4d870d59f552714e807fe2487eb762.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 419, + 176, + 525, + 281 + ], + "blocks": [ + { + "bbox": [ + 419, + 176, + 525, + 281 + ], + "lines": [ + { + "bbox": [ + 419, + 176, + 525, + 281 + ], + "spans": [ + { + "bbox": [ + 419, + 176, + 525, + 281 + ], + "type": "image", + "image_path": "9eaf1819e7835e952cbf55e12298922016bdd0afabd7a22bb6fc2730ef235ddf.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 446, + 282, + 499, + 292 + ], + "lines": [ + { + "bbox": [ + 446, + 282, + 499, + 292 + ], + "spans": [ + { + "bbox": [ + 446, + 282, + 499, + 292 + ], + "type": "text", + "content": "(d) Difference" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 335, + 287, + 360 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 335, + 287, + 360 + ], + "spans": [ + { + "bbox": [ + 46, + 335, + 287, + 360 + ], + "type": "text", + "content": "of parameters, and thus we recommend to use a simple set of parameters to save computation." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 362, + 288, + 517 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 362, + 288, + 517 + ], + "spans": [ + { + "bbox": [ + 46, + 362, + 288, + 517 + ], + "type": "text", + "content": "Effects of image size. It is known that image size can significantly affect the recognition performance. We evaluate the effect of varying input and output sizes of MULLER using MaxViT-B in Tab. 9. Note that the output size of MULLER is indeed the size seen by the backbone, so higher output size typically corresponds to improved accuracy. We observe that using higher input resolutions (e.g., " + }, + { + "bbox": [ + 46, + 362, + 288, + 517 + ], + "type": "inline_equation", + "content": "3 \\times" + }, + { + "bbox": [ + 46, + 362, + 288, + 517 + ], + "type": "text", + "content": ") for MULLER does not yield any further performance gain beyond the baseline setting. Nonetheless, we find that adopting a reasonably large resolution (e.g. " + }, + { + "bbox": [ + 46, + 362, + 288, + 517 + ], + "type": "inline_equation", + "content": "1.6 \\sim 2.5 \\times" + }, + { + "bbox": [ + 46, + 362, + 288, + 517 + ], + "type": "text", + "content": ") is necessary to achieve the expected performance. It is worth highlighting that this is perhaps impacted by the original resolution of images in the benchmark dataset." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 47, + 536, + 130, + 547 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 536, + 130, + 547 + ], + "spans": [ + { + "bbox": [ + 47, + 536, + 130, + 547 + ], + "type": "text", + "content": "4.5. Visualization" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 46, + 557, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 557, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 557, + 287, + 713 + ], + "type": "text", + "content": "We visualize the behavior of the learned resizer in Fig. 4. As can be seen, the MULLER resizer is learned to boost details or textures of the images, while also enhancing the image contrast. These effects can preserve more visual information in the downscaled images over naive resizing, thus making the classification model learn better. As compared to the previous less-controlled resizer [45], MULLER achieves a better balance of human and machine perceptual qualities, due to the strong regularization imbued in its Laplacian-inspired design. We also point out that training MULLER with aliased inputs may produce relatively less sharper images in comparison to Fig. 4. We refer the reader to the supplementary material for visual examples." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 334, + 430, + 348 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 334, + 430, + 348 + ], + "spans": [ + { + "bbox": [ + 306, + 334, + 430, + 348 + ], + "type": "text", + "content": "5. Concluding Remarks" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 354, + 545, + 617 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 354, + 545, + 617 + ], + "spans": [ + { + "bbox": [ + 304, + 354, + 545, + 617 + ], + "type": "text", + "content": "In this paper, we introduce MULLER, an extremely simple and light learned resizer, using multilayer Laplacian decomposition. The proposed resizer only contains 4 trainable parameters with negligible training and inference costs. This allows deploying the resizer as a thumbnail generator to produce optimally downscaled images for sending to remote inference servers, or alternatively as a server side resizer that reduces the inference cost without the necessity of changing the backbone architecture. We show that MULLER not only pushes forward the limit of the state-of-the-art vision Transformer MaxViT on ImageNet classification, but it also consistently improves across a range of widely used architectures, including EfficientNet, MobileNet, and ResNet. Additionally, we provide experiments to substantiate the efficacy of MULLER for various downstream tasks, such as object detection, segmentation, and image quality assessment. As compared to previous methods, MULLER enjoys remarkable generalization ability, owing to the strong regularization provided by its multilayer bandpass design. We believe that our work will inspire future research in this critically important direction: how to better preprocess images for vision tasks." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": "Limitations and future works. We note that if the higher-resolution inputs fail to boost the performance of an specific task, we cannot reasonably expect the learned resizer to provide a substantial performance boost either. Another potential future direction is to train a universal learned resizer that can be a drop-in replacement of the off-the-shelf resizers in existing machine learning frameworks, without necessitating the joint re-training of the backbones." + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6884" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 145 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 145 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 145 + ], + "type": "text", + "content": "[1] Martín Abadi, Ashish Agarwal, Paul Barham, Eugene Brevdo, Zhifeng Chen, Craig Citro, Greg S Corrado, Andy Davis, Jeffrey Dean, Matthieu Devin, et al. Tensorflow: Large-scale machine learning on heterogeneous distributed systems. arXiv preprint arXiv:1603.04467, 2016. 1" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 147, + 288, + 190 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 147, + 288, + 190 + ], + "spans": [ + { + "bbox": [ + 53, + 147, + 288, + 190 + ], + "type": "text", + "content": "[2] Andy Brock, Soham De, Samuel L Smith, and Karen Simonyan. High-performance large-scale image recognition without normalization. In International Conference on Machine Learning, pages 1059-1071. PMLR, 2021. 6" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 191, + 288, + 235 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 191, + 288, + 235 + ], + "spans": [ + { + "bbox": [ + 53, + 191, + 288, + 235 + ], + "type": "text", + "content": "[3] Li-Heng Chen, Christos G Bampis, Zhi Li, Lukáš Krasula, and Alan C Bovik. Estimating the resize parameter in end-to-end learned image compression. arXiv preprint arXiv:2204.12022, 2022. 2, 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 236, + 288, + 280 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 236, + 288, + 280 + ], + "spans": [ + { + "bbox": [ + 53, + 236, + 288, + 280 + ], + "type": "text", + "content": "[4] Li-Heng Chen, Christos G Bampis, Zhi Li, Joel Sole, and Alan C Bovik. A progressive architecture for learned fractional downsampling. In 2021 Picture Coding Symposium (PCS), pages 1-5. IEEE, 2021. 2, 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 281, + 288, + 335 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 281, + 288, + 335 + ], + "spans": [ + { + "bbox": [ + 53, + 281, + 288, + 335 + ], + "type": "text", + "content": "[5] Qiuyu Chen, Wei Zhang, Ning Zhou, Peng Lei, Yi Xu, Yu Zheng, and Jianping Fan. Adaptive fractional dilated convolution network for image aesthetics assessment. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14114-14123, 2020. 7" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 336, + 288, + 390 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 336, + 288, + 390 + ], + "spans": [ + { + "bbox": [ + 53, + 336, + 288, + 390 + ], + "type": "text", + "content": "[6] Wuyang Chen, Xianzhi Du, Fan Yang, Lucas Beyer, Xiaohua Zhai, Tsung-Yi Lin, Huizhong Chen, Jing Li, Xiaodan Song, Zhangyang Wang, and Denny Zhou. A simple single-scale vision transformer for object localization and instance segmentation. CoRR, abs/2112.09747, 2021. 7" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 392, + 288, + 434 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 392, + 288, + 434 + ], + "spans": [ + { + "bbox": [ + 53, + 392, + 288, + 434 + ], + "type": "text", + "content": "[7] Zihang Dai, Hanxiao Liu, Quoc Le, and Mingxing Tan. Coatnet: Marrying convolution and attention for all data sizes. Advances in Neural Information Processing Systems, 34, 2021. 5, 6" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 436, + 288, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 436, + 288, + 491 + ], + "spans": [ + { + "bbox": [ + 53, + 436, + 288, + 491 + ], + "type": "text", + "content": "[8] Xiaoyi Dong, Jianmin Bao, Dongdong Chen, Weiming Zhang, Nenghai Yu, Lu Yuan, Dong Chen, and Baining Guo. Cswin transformer: A general vision transformer backbone with cross-shaped windows. arXiv preprint arXiv:2107.00652, 2021. 4, 5" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 491, + 288, + 557 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 491, + 288, + 557 + ], + "spans": [ + { + "bbox": [ + 53, + 491, + 288, + 557 + ], + "type": "text", + "content": "[9] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020.4,5,6" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 558, + 287, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 558, + 287, + 624 + ], + "spans": [ + { + "bbox": [ + 48, + 558, + 287, + 624 + ], + "type": "text", + "content": "[10] Muhammad Haris, Greg Shakhnarovich, and Norimichi Ukita. Task-driven super resolution: Object detection in low-resolution images. In Neural Information Processing: 28th International Conference, ICONIP 2021, Sanur, Bali, Indonesia, December 8-12, 2021, Proceedings, Part V 28, pages 387-395. Springer, 2021. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 625, + 287, + 669 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 625, + 287, + 669 + ], + "spans": [ + { + "bbox": [ + 48, + 625, + 287, + 669 + ], + "type": "text", + "content": "[11] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 1, 4, 5, 6, 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "type": "text", + "content": "[12] Gao Huang, Zhuang Liu, Laurens Van Der Maaten, and Kilian Q Weinberger. Densely connected convolutional networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4700-4708, 2017. 1" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 27, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 117 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 117 + ], + "type": "text", + "content": "[13] Junjie Ke, Qifei Wang, Yilin Wang, Peyman Milanfar, and Feng Yang. Musiq: Multi-scale image quality transformer. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 5148-5157, 2021. 7" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 118, + 545, + 172 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 545, + 172 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 545, + 172 + ], + "type": "text", + "content": "[14] Alexander Kolesnikov, Lucas Beyer, Xiaohua Zhai, Joan Puigcerver, Jessica Yung, Sylvain Gelly, and Neil Houlsby. Big transfer (bit): General visual representation learning. In European conference on computer vision, pages 491-507. Springer, 2020. 6" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 173, + 545, + 215 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 173, + 545, + 215 + ], + "spans": [ + { + "bbox": [ + 307, + 173, + 545, + 215 + ], + "type": "text", + "content": "[15] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E Hinton. Imagenet classification with deep convolutional neural networks. Advances in neural information processing systems, 25, 2012. 1, 4" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 217, + 545, + 259 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 217, + 545, + 259 + ], + "spans": [ + { + "bbox": [ + 307, + 217, + 545, + 259 + ], + "type": "text", + "content": "[16] Boyi Li, Xiulian Peng, Zhangyang Wang, Jizheng Xu, and Dan Feng. End-to-end united video dehazing and detection. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 32, 2018. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 261, + 545, + 304 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 261, + 545, + 304 + ], + "spans": [ + { + "bbox": [ + 307, + 261, + 545, + 304 + ], + "type": "text", + "content": "[17] Boyi Li, Wenqi Ren, Dengpan Fu, Dacheng Tao, Dan Feng, Wenjun Zeng, and Zhangyang Wang. Benchmarking single-image dehazing and beyond. IEEE Transactions on Image Processing, 28(1):492-505, 2018. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 305, + 545, + 371 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 305, + 545, + 371 + ], + "spans": [ + { + "bbox": [ + 307, + 305, + 545, + 371 + ], + "type": "text", + "content": "[18] Siyuan Li, Iago Bruno Araujo, Wenqi Ren, Zhangyang Wang, Eric K Tokuda, Roberto Hirata Junior, Roberto Cesar-Junior, Jiawan Zhang, Xiaojie Guo, and Xiaochun Cao. Single image deraining: A comprehensive benchmark analysis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3838-3847, 2019. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 372, + 545, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 372, + 545, + 426 + ], + "spans": [ + { + "bbox": [ + 307, + 372, + 545, + 426 + ], + "type": "text", + "content": "[19] Yinxiao Li, Pengchong Jin, Feng Yang, Ce Liu, Ming-Hsuan Yang, and Peyman Milanfar. Comisr: Compression-informed video super-resolution. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2543-2552, 2021. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 426, + 545, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 426, + 545, + 470 + ], + "spans": [ + { + "bbox": [ + 307, + 426, + 545, + 470 + ], + "type": "text", + "content": "[20] Yue Li, Dong Liu, Houqiang Li, Li Li, Zhu Li, and Feng Wu. Learning a convolutional neural network for image compact-resolution. IEEE Transactions on Image Processing, 28(3):1092-1107, 2018. 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 471, + 545, + 525 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 471, + 545, + 525 + ], + "spans": [ + { + "bbox": [ + 307, + 471, + 545, + 525 + ], + "type": "text", + "content": "[21] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In European conference on computer vision, pages 740-755. Springer, 2014. 6" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 526, + 545, + 568 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 526, + 545, + 568 + ], + "spans": [ + { + "bbox": [ + 307, + 526, + 545, + 568 + ], + "type": "text", + "content": "[22] Ding Liu, Bihan Wen, Xianming Liu, Zhangyang Wang, and Thomas S Huang. When image denoising meets high-level vision tasks: A deep learning approach. arXiv preprint arXiv:1706.04284, 2017. 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 570, + 547, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 570, + 547, + 624 + ], + "spans": [ + { + "bbox": [ + 307, + 570, + 547, + 624 + ], + "type": "text", + "content": "[23] Feng Liu, Ronghang Zhu, Dan Zeng, Qijun Zhao, and Xiaoming Liu. Disentangling features in 3d face shapes for joint face reconstruction and recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5216-5225, 2018. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 625, + 545, + 680 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 625, + 545, + 680 + ], + "spans": [ + { + "bbox": [ + 307, + 625, + 545, + 680 + ], + "type": "text", + "content": "[24] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10012-10022, 2021. 1, 4, 5, 6, 7" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "type": "text", + "content": "[25] Zhuang Liu, Hanzi Mao, Chao-Yuan Wu, Christoph Feichtenhofer, Trevor Darrell, and Saining Xie. A convnet for the 2020s. arXiv preprint arXiv:2201.03545, 2022. 5, 6, 7" + } + ] + } + ], + "index": 26 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "6885" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[26] Zhuang Liu, Tinghui Zhou, Hung-Ju Wang, Zhiqiang Shen, Bingyi Kang, Evan Shelhamer, and Trevor Darrell. Transferable recognition-aware image processing. arXiv preprint arXiv:1910.09185, 2019. 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 118, + 287, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 118, + 287, + 150 + ], + "spans": [ + { + "bbox": [ + 49, + 118, + 287, + 150 + ], + "type": "text", + "content": "[27] Peyman Milanfar. A tour of modern image filtering: New insights and methods, both practical and theoretical. IEEE signal processing magazine, 30(1):106-128, 2012. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 151, + 287, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 151, + 287, + 194 + ], + "spans": [ + { + "bbox": [ + 49, + 151, + 287, + 194 + ], + "type": "text", + "content": "[28] Naila Murray, Luca Marchesotti, and Florent Perronnin. Ava: A large-scale database for aesthetic visual analysis. In 2012 IEEE conference on computer vision and pattern recognition, pages 2408-2415. IEEE, 2012. 7" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 195, + 287, + 227 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 195, + 287, + 227 + ], + "spans": [ + { + "bbox": [ + 49, + 195, + 287, + 227 + ], + "type": "text", + "content": "[29] Gaurav Parmar, Richard Zhang, and Jun-Yan Zhu. On buggy resizing libraries and surprising subtleties in fid calculation. arXiv preprint arXiv:2104.11222, 2021. 2, 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 228, + 287, + 292 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 228, + 287, + 292 + ], + "spans": [ + { + "bbox": [ + 49, + 228, + 287, + 292 + ], + "type": "text", + "content": "[30] Adam Paszke, Sam Gross, Francisco Massa, Adam Lerer, James Bradbury, Gregory Chanan, Trevor Killeen, Zeming Lin, Natalia Gimelshein, Luca Antiga, et al. Pytorch: An imperative style, high-performance deep learning library. Advances in neural information processing systems, 32, 2019. 1" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 294, + 287, + 358 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 294, + 287, + 358 + ], + "spans": [ + { + "bbox": [ + 49, + 294, + 287, + 358 + ], + "type": "text", + "content": "[31] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. In C. Cortes, N. Lawrence, D. Lee, M. Sugiyama, and R. Garnett, editors, Advances in Neural Information Processing Systems, volume 28. Curran Associates, Inc., 2015. 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 360, + 287, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 360, + 287, + 392 + ], + "spans": [ + { + "bbox": [ + 49, + 360, + 287, + 392 + ], + "type": "text", + "content": "[32] Rachid Riad, Olivier Teboul, David Grangier, and Neil Zeghidour. Learning strides in convolutional neural networks. arXiv preprint arXiv:2202.01653, 2022. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 394, + 287, + 446 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 394, + 287, + 446 + ], + "spans": [ + { + "bbox": [ + 49, + 394, + 287, + 446 + ], + "type": "text", + "content": "[33] Avinab Saha, Sandeep Mishra, and Alan C Bovik. Reiaq: Unsupervised learning for image quality assessment in the wild. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5846-5855, 2023. 1" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 449, + 287, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 449, + 287, + 491 + ], + "spans": [ + { + "bbox": [ + 49, + 449, + 287, + 491 + ], + "type": "text", + "content": "[34] Mehdi SM Sajjadi, Bernhard Scholkopf, and Michael Hirsch. Enhancenet: Single image super-resolution through automated texture synthesis. arXiv preprint arXiv:1612.07919, 2016. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 493, + 287, + 547 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 493, + 287, + 547 + ], + "spans": [ + { + "bbox": [ + 49, + 493, + 287, + 547 + ], + "type": "text", + "content": "[35] Mark Sandler, Andrew Howard, Menglong Zhu, Andrey Zh-moginov, and Liang-Chieh Chen. Mobilenetv2: Inverted residuals and linear bottlenecks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4510-4520, 2018. 1, 4, 5, 6" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 548, + 287, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 548, + 287, + 602 + ], + "spans": [ + { + "bbox": [ + 49, + 548, + 287, + 602 + ], + "type": "text", + "content": "[36] Vivek Sharma, Ali Diba, Davy Neven, Michael S Brown, Luc Van Gool, and Rainer Stiefelhagen. Classification-driven dynamic image enhancement. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4033-4041, 2018. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 49, + 604, + 287, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 604, + 287, + 668 + ], + "spans": [ + { + "bbox": [ + 49, + 604, + 287, + 668 + ], + "type": "text", + "content": "[37] Wenzhe Shi, Jose Caballero, Ferenc Huszár, Johannes Totz, Andrew P Aitken, Rob Bishop, Daniel Rueckert, and Zehan Wang. Real-time single image and video super-resolution using an efficient sub-pixel convolutional neural network. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1874-1883, 2016. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 49, + 670, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 670, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 49, + 670, + 287, + 712 + ], + "type": "text", + "content": "[38] Chen Sun, Abhinav Shrivastava, Saurabh Singh, and Abhinav Gupta. Revisiting unreasonable effectiveness of data in deep learning era. In Proceedings of the IEEE international conference on computer vision, pages 843-852, 2017. 4" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 126 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 126 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 126 + ], + "type": "text", + "content": "[39] Satoshi Suzuki, Motohiro Takagi, Kazuya Hayase, Takayuki Onishi, and Atsushi Shimizu. Image pre-transformation for recognition-aware image compression. In 2019 IEEE International Conference on Image Processing (ICIP), pages 2686-2690. IEEE, 2019. 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 129, + 545, + 192 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 129, + 545, + 192 + ], + "spans": [ + { + "bbox": [ + 307, + 129, + 545, + 192 + ], + "type": "text", + "content": "[40] Christian Szegedy, Wei Liu, Yangqing Jia, Pierre Sermanet, Scott Reed, Dragomir Anguelov, Dumitru Erhan, Vincent Vanhoucke, and Andrew Rabinovich. Going deeper with convolutions. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1-9, 2015. 1" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 194, + 545, + 247 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 194, + 545, + 247 + ], + "spans": [ + { + "bbox": [ + 308, + 194, + 545, + 247 + ], + "type": "text", + "content": "[41] Christian Szegedy, Vincent Vanhoucke, Sergey Ioffe, Jon Shlens, and Zbigniew Wojna. Rethinking the inception architecture for computer vision. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2818-2826, 2016. 1" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 250, + 545, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 250, + 545, + 293 + ], + "spans": [ + { + "bbox": [ + 308, + 250, + 545, + 293 + ], + "type": "text", + "content": "[42] Hossein Talebi, Damien Kelly, Xiyang Luo, Ignacio Garcia Dorado, Feng Yang, Peyman Milanfar, and Michael Elad. Better compression with deep pre-editing. IEEE Transactions on Image Processing, 30:6673-6685, 2021. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 294, + 545, + 326 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 294, + 545, + 326 + ], + "spans": [ + { + "bbox": [ + 308, + 294, + 545, + 326 + ], + "type": "text", + "content": "[43] Hossein Talebi and Peyman Milanfar. Fast multilayer laplacian enhancement. IEEE Transactions on Computational Imaging, 2(4):496-509, 2016. 4" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 327, + 545, + 358 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 327, + 545, + 358 + ], + "spans": [ + { + "bbox": [ + 308, + 327, + 545, + 358 + ], + "type": "text", + "content": "[44] Hossein Talebi and Peyman Milanfar. Nima: Neural image assessment. IEEE transactions on image processing, 27(8):3998-4011, 2018. 7" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 361, + 545, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 361, + 545, + 403 + ], + "spans": [ + { + "bbox": [ + 308, + 361, + 545, + 403 + ], + "type": "text", + "content": "[45] Hossein Talebi and Peyman Milanfar. Learning to resize images for computer vision tasks. In Proceedings of the IEEE/CVF international conference on computer vision, pages 497-506, 2021. 2, 3, 5, 6, 7, 8" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 404, + 545, + 447 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 404, + 545, + 447 + ], + "spans": [ + { + "bbox": [ + 308, + 404, + 545, + 447 + ], + "type": "text", + "content": "[46] Mingxing Tan and Quoc Le. Efficientnet: Rethinking model scaling for convolutional neural networks. In International conference on machine learning, pages 6105-6114. PMLR, 2019. 1, 4, 5, 6, 7" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 449, + 545, + 480 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 449, + 545, + 480 + ], + "spans": [ + { + "bbox": [ + 308, + 449, + 545, + 480 + ], + "type": "text", + "content": "[47] Mingxing Tan and Quoc Le. Efficientnetv2: Smaller models and faster training. In International Conference on Machine Learning, pages 10096-10106. PMLR, 2021. 5, 6" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 482, + 545, + 525 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 482, + 545, + 525 + ], + "spans": [ + { + "bbox": [ + 308, + 482, + 545, + 525 + ], + "type": "text", + "content": "[48] Xin Tao, Hongyun Gao, Xiaoyong Shen, Jue Wang, and Jiaya Jia. Scale-recurrent network for deep image deblurring. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 8174-8182, 2018. 2" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 526, + 545, + 568 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 526, + 545, + 568 + ], + "spans": [ + { + "bbox": [ + 308, + 526, + 545, + 568 + ], + "type": "text", + "content": "[49] Zhengzhong Tu, Hossein Talebi, Han Zhang, Feng Yang, Peyman Milanfar, Alan Bovik, and Yinxiao Li. Maxim: Multi-axis mlp for image processing. arXiv preprint arXiv:2201.02973, 2022. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 570, + 545, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 570, + 545, + 635 + ], + "spans": [ + { + "bbox": [ + 308, + 570, + 545, + 635 + ], + "type": "text", + "content": "[50] Zhengzhong Tu, Hossein Talebi, Han Zhang, Feng Yang, Peyman Milanfar, Alan Bovik, and Yinxiao Li. Maxvit: Multi-axis vision transformer. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXIV, pages 459-479. Springer, 2022. 1, 2, 4" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 636, + 545, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 636, + 545, + 690 + ], + "spans": [ + { + "bbox": [ + 308, + 636, + 545, + 690 + ], + "type": "text", + "content": "[51] Cristina Vasconcelos, Hugo Larochelle, Vincent Dumoulin, Rob Romijnders, Nicolas Le Roux, and Ross Goroshin. Impact of aliasing on generalization in deep convolutional networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10529-10538, 2021. 6" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 692, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 692, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 692, + 545, + 712 + ], + "type": "text", + "content": "[52] Ashish Vaswani, Prajit Ramachandran, Aravind Srinivas, Niki Parmar, Blake Hechtman, and Jonathon Shlens. Scaling" + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "6886" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 553 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 67, + 72, + 287, + 115 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 287, + 115 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 287, + 115 + ], + "type": "text", + "content": "local self-attention for parameter efficient visual backbones. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12894–12904, 2021. 6" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 118, + 287, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 118, + 287, + 162 + ], + "spans": [ + { + "bbox": [ + 48, + 118, + 287, + 162 + ], + "type": "text", + "content": "[53] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. 1" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 163, + 287, + 196 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 163, + 287, + 196 + ], + "spans": [ + { + "bbox": [ + 48, + 163, + 287, + 196 + ], + "type": "text", + "content": "[54] Zhou Wang. Image quality assessment: from error visibility to structural similarity. IEEE transactions on image processing, 13(4):600-612, 2004. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 197, + 287, + 252 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 197, + 287, + 252 + ], + "spans": [ + { + "bbox": [ + 48, + 197, + 287, + 252 + ], + "type": "text", + "content": "[55] Haiping Wu, Bin Xiao, Noel Codella, Mengchen Liu, Xiyang Dai, Lu Yuan, and Lei Zhang. Cvt: Introducing convolutions to vision transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 22-31, 2021. 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 253, + 287, + 306 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 253, + 287, + 306 + ], + "spans": [ + { + "bbox": [ + 48, + 253, + 287, + 306 + ], + "type": "text", + "content": "[56] Saining Xie, Ross Girshick, Piotr Dólár, Zhuowen Tu, and Kaiming He. Aggregated residual transformations for deep neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1492-1500, 2017. 7" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 308, + 287, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 308, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 48, + 308, + 287, + 342 + ], + "type": "text", + "content": "[57] Runsheng Xu, Jinlong Li, Xiaoyu Dong, Hongkai Yu, and Jiaqi Ma. Bridging the domain gap for multi-agent perception. arXiv preprint arXiv:2210.08451, 2022. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 342, + 287, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 342, + 287, + 407 + ], + "spans": [ + { + "bbox": [ + 48, + 342, + 287, + 407 + ], + "type": "text", + "content": "[58] Runsheng Xu, Hao Xiang, Zhengzhong Tu, Xin Xia, Ming-Hsuan Yang, and Jiaqi Ma. V2x-vit: Vehicle-to-everything cooperative perception with vision transformer. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXXIX, pages 107-124. Springer, 2022. 1" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 409, + 287, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 409, + 287, + 453 + ], + "spans": [ + { + "bbox": [ + 48, + 409, + 287, + 453 + ], + "type": "text", + "content": "[59] Kai Zhang, Wangmeng Zuo, Yunjin Chen, Deyu Meng, and Lei Zhang. Beyond a gaussian denoiser: Residual learning of deep cnn for image denoising. IEEE transactions on image processing, 26(7):3142-3155, 2017. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 454, + 287, + 509 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 454, + 287, + 509 + ], + "spans": [ + { + "bbox": [ + 48, + 454, + 287, + 509 + ], + "type": "text", + "content": "[60] Richard Zhang, Phillip Isola, and Alexei A Efros. Colorful image colorization. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part III 14, pages 649-666. Springer, 2016. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 510, + 287, + 553 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 510, + 287, + 553 + ], + "spans": [ + { + "bbox": [ + 48, + 510, + 287, + 553 + ], + "type": "text", + "content": "[61] Chen Zhao and Bernard Ghanem. Thumbnet: One thumbnail image contains all you need for recognition. In Proceedings of the 28th ACM International Conference on Multimedia, pages 1506-1514, 2020. 2" + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6887" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/4b78daa4-2084-48f2-bdbe-f8d1b9a4826f_content_list.json b/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/4b78daa4-2084-48f2-bdbe-f8d1b9a4826f_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..dbc0242c66a74533751ac9fbfd365a7d7cbf792c --- /dev/null +++ b/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/4b78daa4-2084-48f2-bdbe-f8d1b9a4826f_content_list.json @@ -0,0 +1,1463 @@ +[ + { + "type": "text", + "text": "MUVA: A New Large-Scale Benchmark for Multi-view Amodal Instance Segmentation in the Shopping Scenario", + "text_level": 1, + "bbox": [ + 119, + 128, + 851, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Zhixuan Li $^{1}$ Weining Ye $^{1}$ Juan Terven $^{2}$ Zachary Bennett $^{2}$ Ying Zheng $^{2}$ Tingting Jiang $^{1,*}$ Tiejun Huang $^{1,3}$", + "bbox": [ + 225, + 202, + 740, + 239 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{1}$ National Engineering Research Center of Visual Technology, National Key Laboratory for Multimedia Information Processing, School of Computer Science, Peking University, Beijing 100871, China", + "bbox": [ + 127, + 241, + 841, + 273 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{2}$ AiFi Inc., California 94010, United States", + "bbox": [ + 339, + 275, + 630, + 290 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "3 Beijing Academy of Artificial Intelligence, Beijing 100084, China {zhixuanli,ywning}@pku.edu.cn, {juan,zachary}@aifi.com, yingz@alumni.gsb.stanford.edu, {ttjiang,tjhuang}@pku.edu.cn", + "bbox": [ + 225, + 292, + 745, + 345 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 378, + 313, + 395 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Amodal Instance Segmentation (AIS) endeavors to accurately deduce complete object shapes that are partially or fully occluded. However, the inherent ill-posed nature of single-view datasets poses challenges in determining occluded shapes. A multi-view framework may help alleviate this problem, as humans often adjust their perspective when encountering occluded objects. At present, this approach has not yet been explored by existing methods and datasets. To bridge this gap, we propose a new task called Multi-view Amodal Instance Segmentation (MAIS) and introduce the MUVA dataset, the first MUlti-View AIS dataset that takes the shopping scenario as instantiation. MUVA provides comprehensive annotations, including multi-view amodal/visible segmentation masks, 3D models, and depth maps, making it the largest image-level AIS dataset in terms of both the number of images and instances. Additionally, we propose a new method for aggregating representative features across different instances and views, which demonstrates promising results in accurately predicting occluded objects from one viewpoint by leveraging information from other viewpoints. Besides, we also demonstrate that MUVA can benefit the AIS task in real-world scenarios.", + "bbox": [ + 75, + 411, + 473, + 744 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 768, + 209, + 786 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The amodal instance segmentation (AIS) task aims to determine an object's entire shape, encompassing its visible and occluded components. AIS task is more challenging than the visible instance segmentation task [23, 11]", + "bbox": [ + 75, + 795, + 468, + 856 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/9b2be6dd5e1bed2e89f851c89adf672e90b2bebd49153de9e77dcb2dcc34349d.jpg", + "image_caption": [ + "Figure 1. Comparison of the impact of ill-posed problems on amodal prediction in single-view and multi-view input settings. (a) In single-view input, ambiguity arises due to multiple candidates for the occluded object. (b) Multi-view input helps alleviate ambiguity and improves amodal prediction accuracy." + ], + "image_footnote": [], + "bbox": [ + 524, + 378, + 869, + 612 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "as it lacks occluded region appearance. Despite its complexity, the AIS task has significant implications for various industrial applications that encounter occlusion problems, such as robotic arm grasping [1], pedestrian re-identification [34, 36, 29], automatic driving [27, 28], and self-checkout systems in supermarkets [8].", + "bbox": [ + 496, + 704, + 893, + 797 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Although numerous datasets [19, 40, 8, 27, 13] and methods [19, 40, 8, 27, 13, 38, 33, 21] have been proposed since the AIS task was firstly introduced in 2016 by Li and Malik [19], current AIS datasets and methods rely on a single-view approach, suffering from the ill-posed problem. For example, as shown in Fig. 1(a), directly deducting", + "bbox": [ + 496, + 809, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding author", + "bbox": [ + 93, + 862, + 222, + 875 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "1The proposed MUVA dataset can be downloaded from this link: https://zhixuanli.github.io/project_2023_ICCVMUVA.", + "bbox": [ + 76, + 875, + 468, + 900 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "23504", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "the complete shape from a single-view image is extremely challenging due to the presence of occluded regions with multiple potential candidates. This is because distinct objects can share the same visible appearance but differ in shape within the occluded region. However, as shown in Fig. 1(b), humans tend to observe occluded objects from multiple angles to obtain accurate predictions.", + "bbox": [ + 75, + 90, + 470, + 196 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Inspired by this observation, this paper proposes a novel task called MAIS (Multi-view Amodal Instance Segmentation), which predicts amodal segmentations through multiple viewpoints. The task is designed for real-world applications, under the assumption that the number of viewpoints and field of vision is limited, and objects in the scene are closely distributed with reasonable occlusion. These assumptions contribute to the difficulty and practical significance of the MAIS task.", + "bbox": [ + 75, + 199, + 468, + 335 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To study the MAIS task, creating a multi-view AIS dataset is essential. However, annotating multi-view data based on existing or newly collected real-world data involve significant efforts and may not be accurate in identifying shapes of occluded regions. This is because manually annotated amodal masks in real-world datasets are often inaccurate and inconsistent due to the varying shape prior knowledge of annotators, as shown in Fig. 2 (copied from [40]). Therefore, using a synthetic approach would be more precise and controllable. To create a synthetic dataset, one option is to build upon existing synthetic AIS datasets [6, 13, 14]. However, these datasets lack high-quality 3D models and sufficient occlusion. To overcome the limitation, we propose to create a new synthetic dataset comprising reconstructed high-quality 3D models and sufficient occlusion by controlling the distribution of objects. As an initial step in exploring the MAIS task, we limit our dataset construction to a single scenario. Specifically, the shopping scenario is selected due to its potential for multiple camera arrangements and its tendency for severe occlusion when goods are piled up. Consequently, we introduce MUVA, a novel MUlti-View Amodal Instance Segmentation dataset. The dataset creation process follows a standard three-step approach. Initially, 3D artists construct models from images collected from on-sale items. Next, 3D models are then selected and placed in a 3D scene with careful compositions to control the occlusion degree. Finally, multi-view images are captured by six simulated cameras to simulate a real-world self-checkout setting. Each image is extensively annotated with visible/amodal segmentation masks, depth maps, occlusion orders, and 3D models.", + "bbox": [ + 75, + 338, + 470, + 806 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To our best knowledge, MUVA is the first and only multi-view AIS dataset currently available. Unlike real-world-based AIS datasets [19, 40, 8, 27], MUVA provides precise annotations in the occluded region due to its synthetic nature and known ground-truth 3D models. Besides, MUVA is also the largest image-level AIS dataset in terms", + "bbox": [ + 75, + 809, + 468, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "of both images and instances.", + "bbox": [ + 498, + 90, + 696, + 106 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To exploit the multi-view information in MUVA, we introduce MASFormer, a novel method that aggregates information across different views and instances. Through comparative experiments with existing single-view-based AIS methods, we demonstrate that MASFormer significantly outperforms these methods by effectively utilizing multiview information. Additionally, our approach can accurately predict objects that are severely occluded from one angle by incorporating information from other angles.", + "bbox": [ + 496, + 109, + 890, + 247 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/f214564f2001503276c7bc61ee05cceba21d2b41c1e1a2ed9a71b657a6733993.jpg", + "image_caption": [ + "Figure 2. Two examples of COCOA [40] dataset, displaying multiple annotated occluded regions by different annotators." + ], + "image_footnote": [], + "bbox": [ + 524, + 266, + 867, + 321 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Our contributions are summarized as follows: 1) A new task named MAIS is proposed to explore the AIS task under the multi-view setting for alleviating the ill-posed problem in the AIS task. 2) A novel dataset named MUVA is proposed for the MAIS task in the multi-view setting for shopping scenarios. To our best knowledge, MUVA is the first AIS dataset under the multi-view setting. 3) A new method named MASFormer is proposed to collect both view-level and instance-level information for solving the ill-posed problem in the AIS task. The experimental results show the efficiency of the multi-view setting over the single-view approach.", + "bbox": [ + 496, + 378, + 890, + 561 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 587, + 640, + 603 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Amodal Instance Segmentation Datasets", + "text_level": 1, + "bbox": [ + 500, + 616, + 844, + 632 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Various single-view-based AIS datasets have been proposed, including the image and video levels. (1) For the image level, most of the datasets are re-annotated manually based on the existing datasets for the visible instance segmentation (VIS) [5, 17, 30] task. For example, COCOA [40, 8], BSDSA [40], KINS [27] and D2SA [8] are extended based on the VIS datasets, including COCO [23], BSDS [25], KITTI [9] and D2S [7]. However, human annotation of occluded regions in image-level datasets may lack accuracy and consistency due to variations in the annotator's perception of amodal shape. Besides, DYCE [6] is a synthetic dataset for indoor furniture. (2) For the video level, two synthetic datasets, SAIL-VOS [13] and SAIL-VOS 3D [14] have been generated based on the GTA 3D game, containing daily-life scenes. Compared to video-level datasets with temporal consistency, MUVA exhibits higher shape variability across different viewpoints.", + "bbox": [ + 496, + 643, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "23505", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/c882e580aa6a8a90188a6f72306a6f0204727a1990f5d27f963e9f87a4db1aec.jpg", + "image_caption": [ + "Figure 3. The pipeline of dataset generation. (a) For each object, 2D images are captured from up, down, left, right, front, and back, respectively. Then 3D artists use the collected images to reconstruct the 3D models. (b) For each scene, 3D models are randomly selected and placed with different amounts and orientations. (c) For each scene, six views are used to capture the data, including the RGB images and various annotations." + ], + "image_footnote": [], + "bbox": [ + 127, + 89, + 844, + 286 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Amodal Instance Segmentation Methods", + "text_level": 1, + "bbox": [ + 76, + 375, + 424, + 388 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "AIS methods employ various cues for amodal completion and can be categorized into three types based on relevant literature. First, numerous methods are adapted from VIS methods. Li and Malik [19] use Iterative Instance Segmentation [18] to solve the amodal problem. ORCNN [8] extends Mask-RCNN for simultaneous visible and amodal segmentations. ASN [27] learns features with a proposed multi-level aggregation module. OAFformer [20] proposes to learn the occlusion discriminative queries with a transformer-base network. Second, some studies utilize the relative occlusion order between objects, including SLN [38] predicts and combines the relative orders, and Deocclusion [35] employs a self-training method to learn an ordering map for guiding the amodal completion. Third, some studies use the shape prior knowledge to help infer the shape of the occluded region, such as Amodal-VAE [24], ShapeDict [33], GIN [22] and A3D [21]. However, the multi-view information is not utilized in existing methods due to the absence of a suitable dataset. Based on the proposed MUVA dataset, this paper presents a 2D approach to leverage multi-view knowledge. Instead of using sophisticated 3D approaches like reconstruction, our 2D approach can be easily applicable to real-world scenarios without requiring 3D supervision signals.", + "bbox": [ + 75, + 398, + 472, + 762 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. MUVA: Multi-view Amodal Dataset", + "text_level": 1, + "bbox": [ + 76, + 782, + 403, + 797 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "MUVA comprises 1,801 distinct 3D objects reconstructed from multi-view photos. These objects are utilized to fabricate 4,401 scenes with diverse object placements. 26,406 RGB images are then produced from six cameras, each from differing viewpoints. The dataset includes thorough annotations, such as depth maps, 3D mod", + "bbox": [ + 75, + 810, + 468, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "els, and amodal/visible masks. The dataset split of MUVA, including train, validation and test, are shown in the supplementary material.", + "bbox": [ + 498, + 375, + 890, + 420 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Dataset Contents", + "text_level": 1, + "bbox": [ + 500, + 431, + 668, + 446 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The contents of MUVA including images and corresponding annotations are introduced below. RGB images are captured from each camera view with a resolution of $1920 \\times 1080$ . The high-quality 3D reconstructed models lead to final rendered RGB images with rich scene details and high visual quality. Six types of annotations are available for each RGB image. (1) The segmentation annotations of instances contain both visible and amodal instance masks. These are generated by the 3D simulation software, resulting in higher accuracy compared to manual annotations. Moreover, the occluded region mask annotations are more precise compared to human-annotated amodal masks which may vary between annotators. (2) Depth maps are produced to reflect the value of each pixel with regard to its distance from the relevant camera to the 3D object. The depth map registers distance for visible regions exclusively, excluding amodal regions. (3) The occlusion order specifies the list of other objects occluded by this one. (4) Accompanying high-quality 3D models are included. (5) The bounding boxes and area of both visible and amodal masks derived from corresponding masks are provided.", + "bbox": [ + 496, + 455, + 890, + 773 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Dataset Generation", + "text_level": 1, + "bbox": [ + 500, + 785, + 687, + 799 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "A universal pipeline is designed to generate the synthetic dataset MUVA in three stages: building 3D models, placing 3D models, and capturing data, as illustrated in Fig. 3.", + "bbox": [ + 498, + 809, + 890, + 854 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3D Model Building. In this stage, 3D models are created as the foundation for the 3D scene, as presented in Fig. 3 (a). This stage contains two steps: (1) capturing six differ", + "bbox": [ + 498, + 854, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "23506", + "bbox": [ + 478, + 945, + 519, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/c88e1e52f8c996ef9612c1bdc613fda68e067c6956f483df054a648f62858de0.jpg", + "image_caption": [ + "Figure 4. The histogram of the number of instances for four parent categories (bags, others, bottles, boxes) and corresponding subcategories. Non-rigid categories are noted with star stripes. Best viewed in color." + ], + "image_footnote": [], + "bbox": [ + 101, + 90, + 870, + 284 + ], + "page_idx": 3 + }, + { + "type": "table", + "img_path": "images/ccfc077a44903f135fe058ca2ca61b47bfecd03b9bec94b3f02e7897fe8dd882.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
DatasetPublicationData TypeMultiple Views# Image# InstanceScenarioSynthetic or Real3D ModelDepth# CategoriesResolution (pixels)
SAIL-VOS [13]CVPR'19video-111,6541,896,295daily lifesynthetic-✓1621M
SAIL-VOS 3D [14]CVPR'21video-237,6113,460,213daily lifesynthetic✓✓1781M
COCOA [40]CVPR'17image-5,00046,314daily lifereal--N/A0.28M
BSDSA [40]CVPR'17image-5003,739daily lifereal--N/A0.15M
DYCE [6]CVPR'18image-5,50085,975daily lifesynthetic--791M
KINS [27]CVPR'19image-14,991190,626streetreal--80.47M
D2SA [8]WACV'19image-5,60028,720shoppingreal--603M
COCOA-cls [8]WACV'19image-3,50110,562daily lifereal--800.28M
MUVAN/Aimage✓26,406198,573shoppingsynthetic✓✓202M
", + "bbox": [ + 109, + 333, + 864, + 479 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Table 1. Comparison with existing amodal instance segmentation datasets. # means the number of this item. Bold numbers denote the largest one in each column among image-level datasets.", + "bbox": [ + 75, + 488, + 892, + 517 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "ent images of each object to provide adequate information for 3D reconstruction, and (2) utilizing MAYA, a 3D modeling software, to reconstruct and manually refine the 3D objects iteratively by 3D artists. This process results in the reconstruction of 1801 distinct 3D objects, each with reconstructed shape and texture.", + "bbox": [ + 75, + 541, + 470, + 633 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3D Model Placing. This stage involves generating 3D scenes by selecting and placing 3D object models. It comprises two steps: 3D model selection and placement, as depicted in Fig. 3 (b). First, a shelf is created as a platform for scene construction, and 3D models are randomly chosen from those reconstructed in the previous stage. Second, placement settings, including object number, orientation, and position, are varied randomly to enhance diversity. The number of objects can range from less than 10 to more than 10, and their upright or flat placement is randomized. Object positions are also randomized, ensuring they are within the shelf's range. Finally, Unity3D software is used to render the scene. The physical simulation utilizes non-deformable 3D models with collision detection to prevent object penetration. The scenes were illuminated uniformly and gravity was applied to mimic realistic conditions. Creating all 1801 3D models required approximately", + "bbox": [ + 75, + 643, + 472, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "600 hours with a 20-minute time frame for each model. The cost of generating the models totaled approximately 15,000 USD at a rate of 25 USD per hour for each 3D artist.", + "bbox": [ + 496, + 541, + 893, + 585 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Data Capture. The simulated scene depicted in Fig. 3 (c) provides various types of data for sampling. Six cameras are positioned in the front to capture sparse views and simulate the self-checkout setting, ensuring the applicability of MUVA to real-life scenarios. For each view, RGB images and numerous annotations are generated.", + "bbox": [ + 496, + 588, + 893, + 678 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The above dataset generation pipeline is adaptable for creating datasets for other vision tasks, such as indoor 3D reconstruction [4] and person re-identification [31].", + "bbox": [ + 496, + 680, + 893, + 726 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Dataset Statistics", + "text_level": 1, + "bbox": [ + 500, + 739, + 669, + 753 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "MUVA dataset comprises 26,406 images with 198,573 instances categorized into four parent categories (bags, bottles, boxes, and others), and 20 sub-categories that include both rigid and non-rigid objects. The instance ratio of each category is presented in Fig. 4. The dataset contains $27.41\\%$ non-rigid objects, such as the \"Plastic Bag,\" which provides shape variations. The proposed dataset includes high-resolution images of $1920 \\times 1080$ pixels, providing rich details of the objects' edges and surfaces.", + "bbox": [ + 496, + 763, + 893, + 902 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "23507", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/59ecc73200a81a1ca44d48210edc61a7caa5cce1a99ca61c57597a2d3b22de22.jpg", + "image_caption": [ + "Figure 5. Overall architecture of our method. There are two stages in our method, including the Feature Extraction Stage and the Multi-view Aggregation Stage. The first stage aims to extract the features of each instance from all views. The second stage utilizes the relationship of features at the instance level and view level, respectively, to generate accurate predictions." + ], + "image_footnote": [], + "bbox": [ + 127, + 103, + 844, + 292 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.4. Comparison with Existing Datasets", + "text_level": 1, + "bbox": [ + 76, + 372, + 385, + 388 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Tab. 1 presents a comparison between MUVA and other AIS datasets, including video and image-level datasets such as COCOA [40], BSDSA [40], DYCE [6], KINS [27], D2SA [8] and COCOA-cls [8]. MUVA stands out as the only dataset specifically designed for the multi-view AIS task and the only synthetic image-level dataset that provides 3D models. The 3D models used to build the dataset are publicly available to support new methods for the AIS task. Additionally, MUVA and D2SA are the only two datasets for the shopping scenario. MUVA's synthetic nature leads to consistent and higher-quality annotations than human-annotated datasets. Moreover, MUVA has the largest number of images and instances among image-level datasets, and is the only dataset at the image level that contains depth maps, which can potentially help with the AIS task.", + "bbox": [ + 75, + 395, + 473, + 623 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/82e130be56a55d06674a770470c441d6d104fa6cdbed62ba50f0c7652fd45ff7.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Datasetsimplicity ↓convexity ↓
visibleamodalvisibleamodal
BSDS-A0.7180.8340.6160.643
COCO-A0.7460.8560.6580.685
KINS0.7090.8300.6100.639
MUVA0.9590.8010.9230.963
", + "bbox": [ + 112, + 636, + 444, + 726 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Table 2. Complexity is evaluated through simplicity and convexity metrics. Small values of these metrics indicate a complex dataset. A circle shape yields the maximum value of 1.0 for both metrics.", + "bbox": [ + 76, + 734, + 468, + 777 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Shape Complexity. To assess the shape complexity of mask annotations contained in MUVA, metrics proposed by COCOA [40] is used. These metrics include convexity and simplicity for both visible and amodal masks. As shown in Tab. 2, MUVA has the lowest shape simplicity (0.801) and the highest convexity (0.963) of amodal masks. The high convexity can be attributed to the presence of goods such", + "bbox": [ + 75, + 794, + 470, + 902 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "as bags, bottles, and boxes, which possess naturally convex shapes. Conversely, the low simplicity confirms that the shapes within MUVA are complex. For instance, a plastic bag with zigzagged boundaries exhibits high convexity but low simplicity.", + "bbox": [ + 496, + 372, + 893, + 449 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.5. Applications", + "text_level": 1, + "bbox": [ + 500, + 458, + 633, + 474 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "MUVA provides diverse annotations that can be used for multiple research tasks. For example, using instance IDs from different viewpoints can lead to a new task of multi-view amodal instance segmentation (MAIS), which involves matching and segmenting the same instance from multiple viewpoints. High-quality 3D models can be used for single/multiple-view 3D reconstruction. The provided relative depth order annotation allows for occlusion order prediction. Finally, the depth map from the object to the camera can be utilized for depth estimation.", + "bbox": [ + 496, + 481, + 893, + 632 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Method", + "text_level": 1, + "bbox": [ + 500, + 646, + 589, + 660 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "This paper focuses on the newly formulated multi-view amodal instance segmentation (MAIS) task. This section proposes a network designed for the MAIS task, named Multi-view Amodal Segmentation Transformer (MAS-Former). The task definition, overall architecture, and the proposed new modules are introduced in the following.", + "bbox": [ + 496, + 671, + 893, + 763 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Overview", + "text_level": 1, + "bbox": [ + 500, + 771, + 609, + 786 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Problem Definition. Given $N$ input images from $N$ viewpoints, the MAIS task aims to predict $K$ instance-level segmentation masks for interested objects in each image.", + "bbox": [ + 496, + 794, + 890, + 840 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Overall Architecture. The whole pipeline of the proposed method contains two stages, including the Feature Extraction Stage (FES) and the Multi-view Aggregation Stage (MAS). (1) The FES extracts features of each instance", + "bbox": [ + 496, + 840, + 893, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "23508", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "from all angles. (2) The MAS takes the instances' feature from FES as input and optimizes from two aspects, including aggregating all instances' features of the same view and all views' features of the same instance. Finally, the amodal instance predictions of objects in all images are generated after fusion.", + "bbox": [ + 78, + 90, + 467, + 180 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Feature Extraction Stage", + "text_level": 1, + "bbox": [ + 78, + 191, + 303, + 208 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "This stage aims to extract features from all views simultaneously. As shown in Fig. 5, the Backbone takes for $N$ images as input and extracts representative features for $K$ instances, including low-level structural details and high-level semantic information. Next, the CNN Decoder up-samples the representative features and generates multilevel features containing all objects' information. Then a Transformer Decoder is employed to output features $F_{FES}$ corresponding to all objects in all views. Bipartite matching [2] is used to find the correspondence between predictions and supervisions, to specify the view id and instance id of each feature.", + "bbox": [ + 78, + 215, + 467, + 395 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Multi-view Aggregation Stage", + "text_level": 1, + "bbox": [ + 78, + 407, + 339, + 424 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "As shown in Fig. 5, this stage aims to enhance the extracted features $F_{FES}$ from two aspects, including view-level and instance-level. Two branches are designed for the two aspects, respectively.", + "bbox": [ + 78, + 431, + 467, + 491 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "View-level Aggregation. This branch aims to utilize the relationship between features of all instances in the same view for enhancing each instance's feature quality. Firstly, for input features $F_{FES}$ including all objects in all views, an View Feature Grouping module takes features of the same view into the same group. Then the View-level Attention module learns the correlation between all instances' features in the same view. Finally, the feature of each instance is enhanced by integrating all correlated instances' features in the same view. Here the correlation between different features is computed by cosine similarity. And the self-attention [32] is used to construct this module. Please refer to our supplementary material for detailed explanations of the network. Besides, this module requires objects in different views could be identified and matched. To achieve this, for each instance, both the view id and the instance id are predicted by the network and supervised by using the bipartite matching [2] to match between the prediction and ground truth.", + "bbox": [ + 78, + 492, + 467, + 777 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Instance-level Aggregation. This module aims to use features of the same instance in all views to improve the feature quality of each instance. First, the Instance Feature Grouping module takes features of the same instance across all views to the same group. Next, for each group, the Instance-level Attention module learns correlations between features of the same instance in different views and integrates associated features by using the self-attention [32]", + "bbox": [ + 78, + 779, + 467, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "mechanism.", + "bbox": [ + 503, + 92, + 581, + 104 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Finally, a CNN-based fuse layer is used to merge the output features of two branches for the final prediction of amodal masks. With the aggregation of two branches, the feature representations of all instances can be enhanced, and more precise amodal segmentation results can be obtained.", + "bbox": [ + 503, + 107, + 890, + 181 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 503, + 200, + 629, + 217 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "This section first compares the newly proposed method MASFormer with existing single-view-based state-of-the-art AIS methods on the proposed MUVA dataset. Then the ablation studies are conducted to show the effectiveness of amount and order for the input viewpoints and components of the proposed method.", + "bbox": [ + 503, + 226, + 890, + 316 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/1609ecd625b9c222dc14a25ebc64e13e4e470a5ccdffbe006110b003fa20c639.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodPublicationAPAP50AP75AR
Mask-RCNN [11]ICCV'1717.226.618.748.8
ORCNN [8]WACV'197.825.92.124.7
SLN [38]ACM MM'196.920.25.622.9
DeepSnake [26]CVPR'207.711.97.423.8
BCNet [16]CVPR'2123.128.925.040.9
ShapeDict [33]AAAI'219.936.01.327.8
E2EC [37]CVPR'2211.815.712.925.5
Baseline (1 view)CVPR'2217.826.118.029.2
Baseline (6 views)CVPR'2222.935.522.336.4
Ours (1 view)N/A25.638.025.641.2
Ours (6 views)N/A39.455.940.351.8
", + "bbox": [ + 535, + 330, + 859, + 473 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/fdf2b7a1905c5d9beec339279d7839e42c157d357f23f1620e21481431fb63ef.jpg", + "table_caption": [ + "Table 3. Compared with state-of-the-art methods on MUVA. In each column, the best is in bold, and the second-best is underlined." + ], + "table_footnote": [], + "table_body": "
MethodResNet-50ResNet-101ResNeXt-101
MaskRCNN17.219.119.8
BCNet23.125.326.6
E2EC11.814.215.9
Ours (6 views)39.442.543.0
", + "bbox": [ + 519, + 541, + 877, + 618 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 4. Performance of methods with stronger backbones.", + "bbox": [ + 522, + 628, + 867, + 641 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Experimental Settings. The baseline method only contains the first stage FES in the proposed method MAS-Former, which is implemented following the video instance segmentation method Mask2Former [3] as an instantiation. The baseline method can take multi-view images as input and outputs amodal segmentation masks, the same as MAS-Former. ResNet-FPN-50 [12] is employed as the backbone for all methods. The results are evaluated using the AP and AR metric, commonly used to measure the precision and recall of prediction. For fairness, all experiments use the same training dataset of MUVA to train and the same validation dataset of MUVA to validate. The ground truth of all methods is the same, including the bounding boxes and masks for amodal and visible regions, image ids, and instance ids. The ground-truth camera viewpoint information and 3D models are not used for fairness.", + "bbox": [ + 503, + 657, + 890, + 898 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "23509", + "bbox": [ + 478, + 945, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/2158de3ad8dcc0542226875e4647873673e85313d756928b263050f6feef2b25.jpg", + "image_caption": [ + "Figure 6. Visualization comparisons between BCNet [16] and ours on MUVA, trained with one viewpoint (1V) and six viewpoints (6V). For masks, different colors denote different instances, and the same instance in different angles has the same color. Red circles indicate regions should be focused. Zoom in for a better view. In the first and third columns, even if a bottle is severely occluded, it can be predicted accurately by our method. Moreover, our method trained with 6 views performs better than training with a single view." + ], + "image_footnote": [], + "bbox": [ + 122, + 89, + 851, + 325 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.1. Multi-view Amodal Instance Segmentation", + "text_level": 1, + "bbox": [ + 76, + 414, + 442, + 431 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Tab. 3 shows the comparison results of some existing AIS methods on MUVA. Several state-of-the-art methods designed for single-view datasets are compared. For baseline and the proposed method MASFormer, two kinds of input are used during training, one is a single view, and the other is six. Note that the amount of training data is the same for these two settings.", + "bbox": [ + 75, + 441, + 470, + 547 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We compare the results at three levels, including one-view, one vs. six views, and six-view levels. (1) As shown in Tab. 3, when only using one view for training, our proposed method MASFormer achieves the best performance $(25.6\\% AP, 38.0\\% AP_{50}, 25.6\\% AP_{75}, 41.2\\% AR)$ on all metrics. MASFormer outperforms the best performance of single-view-based methods with $2.7\\% AP, 2.0\\% AP_{50}, 0.6\\% AP_{75}$ , and $0.2\\% AR$ . The results demonstrate the effectiveness of the proposed view-level attention module, which can learn the relationship between different instances of the same view and improve the amodal prediction with the help of a learned relationship. (2) Both ours and the baseline method achieve better performance when using six views than one view for training. The results show that even with the same training data, using more views as input for training can improve the prediction. (3) When both methods use six views for training, our method can outperform the baseline method with $16.5\\%$ AP. The results show the effectiveness of the proposed instance-level attention module, which learns and benefits from the relationship between different views of the same instance. Besides, the performance of methods with stronger backbones is shown in Tab. 4. Stronger backbones bring improvements for all", + "bbox": [ + 75, + 553, + 470, + 901 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "methods, while the proposed MASFormer still achieves the best performance. Qualitative results are shown in Fig. 6.", + "bbox": [ + 498, + 415, + 890, + 446 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/b049bc092b6d8bc9041ef9b57f1bb8de1a1d0f5f48633f5707de11d2ad488a88.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
SettingTraining DatasetTesting DatasetAP
1D2SAtrainD2SAval63.5
2MUVAtrainD2SAval41.9
3D2SAtrain + MUVAtrainD2SAval68.4
", + "bbox": [ + 509, + 458, + 888, + 523 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 5. Performance of MASFormer evaluated on the validation set of D2SA dataset and trained with different combinations of source-domain datasets for training. For the two datasets, only data of overlapped categories are used.", + "bbox": [ + 498, + 532, + 893, + 589 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.2. Generalization to Real-world Scenarios", + "text_level": 1, + "bbox": [ + 500, + 604, + 836, + 619 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In this section, we demonstrate the generalization ability of the proposed dataset and method on real-world scenarios under single-view and multi-view settings, respectively.", + "bbox": [ + 496, + 628, + 890, + 672 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Single-view Generalization. To validate generalization ability in real-world scenarios, the MUVA dataset is utilized under a single-view setting. To be specific, we employ settings of the domain generalization [39, 10, 15] task to evaluate the generalization ability of learning from a source domain, typically synthetic datasets, to out-of-distribution target domains like real-world datasets. Specifically, the MUVA synthetic dataset and real-world AIS dataset D2SA [8] are used in this study. D2SA contains 60 categories, of which 18 categories overlap with MUVA. More information about the category labels can be found in the supplementary material. The following experiments only consider data from the overlapping categories. Three settings were adopted as presented in Tab. 5. Firstly, MASFormer is trained and evaluated on the train and validation sets of", + "bbox": [ + 496, + 674, + 892, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "23510", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "D2SA datasets, demonstrating its ability to generalize well on real-world data. Secondly, MASFormer is trained on the synthetic MUVA dataset and evaluated on the real-world dataset D2SA, with results validating the generalizability of the synthetic MUVA dataset. Lastly, mixing D2SA and MUVA for training lead to a $4.9\\%$ AP improvement, indicating the benefits of using MUVA in a real-world scenario.", + "bbox": [ + 75, + 90, + 472, + 196 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/e726f945697326db7618159e11eb156c1abeeae538bdbad3711cdcfd37f2a0a1.jpg", + "image_caption": [ + "Figure 7. Qualitative results of a real-world case. Red circles indicate differences between ours and BCNet. Zoom in for a better view." + ], + "image_footnote": [], + "bbox": [ + 83, + 210, + 468, + 375 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Multi-view Generalization. Considering there is no existing multi-view real-world AIS dataset, we construct a real-world shopping scenario to obtain multi-view data for validating the generalization ability of the proposed dataset and method. Images are captured from the left, middle, and right sides, respectively. MASFormer trained with six views and BCNet are used. And the train set of MUVA is utilized for training. As shown in Fig. 7, MASFormer can obtain good amodal segmentation results, demonstrating the generalization ability of MUVA to real-world scenarios. Moreover, when compared with BCNet, MASFormer performs better consistently on all viewpoints, validating its potential for generalizing to the real-world scene.", + "bbox": [ + 75, + 438, + 468, + 633 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/cdcfc7a82622daf273c7226a98962a187c5537b6f15a5322c59ddb6ebbf9cb00.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Views Order# ViewsAPAP50AP75AR
N/A125.638.025.639.2
Fixed Order226.238.026.339.8
328.042.927.740.9
430.945.630.943.5
534.149.034.747.4
637.953.938.651.4
Random Order226.939.527.140.4
328.441.728.442.9
432.846.633.445.6
536.952.737.250.5
639.455.940.351.8
", + "bbox": [ + 94, + 646, + 454, + 806 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.3. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 849, + 230, + 867 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We conducted ablation study experiments for MAS-Former, examining the impact of the number and order of", + "bbox": [ + 76, + 869, + 470, + 900 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "input viewpoints, the effectiveness of attention modules, and computational cost.", + "bbox": [ + 496, + 90, + 888, + 119 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Viewpoints Count and Order. Tab 6 presents some combinations of the number and order of input viewpoints used for training in the proposed MASFormer method. The same amount of training data is used for all experiments. Performance consistently improves as the number of input views increases, regardless of whether their order is fixed (rows # 2 to # 6) or random (rows # 7 to # 11). These results show that using more views for training can improve performance and multi-view data is crucial for amodal instance segmentation. When the number of input views is constant, the impact of the input views' order is analyzed below. As shown in Tab. 6, results of random input order outperform fixed order ones with the equal number of input views. For example, random order improves the $AP$ metric with the following percentages compared to fixed order: $0.7\\%$ (2 views), $0.4\\%$ (3 views), $1.9\\%$ (4 views), $2.8\\%$ (5 views) and $1.5\\%$ (6 views). Results show that randomizing input image ordering of various viewpoints leads to increased training sample distribution and improved effectiveness.", + "bbox": [ + 496, + 121, + 890, + 421 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/c77b30f25e9d0e4ad5937de54c2c430af5d379d691d86b70725073794cb636ec.jpg", + "table_caption": [ + "Table 6. Effect of fixing views input order and views amount. In each column, the best is in bold, and the second-best is underlined." + ], + "table_footnote": [], + "table_body": "
IndexView-levelInstance-levelAPAP50AP75AR
122.935.522.336.4
2✓28.743.128.341.6
3✓34.149.034.747.4
4✓✓39.455.940.351.8
", + "bbox": [ + 529, + 434, + 867, + 506 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Attention Modules. Tab. 7 shows the ablation study of proposed attention modules proposed in our MASFormer method, using six input views with random order. The proposed view-level attention module improves $AP$ performance from $22.9\\%$ to $28.7\\%$ by learning feature relationships within the same view. Instance-level attention module achieves an $11.2\\%$ improvement by utilizing multi-view features of the same instance. Both attention modules combined result in a $39.4\\%$ $AP$ performance, surpassing individual settings.", + "bbox": [ + 496, + 540, + 890, + 691 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/1ecff08027f2d8610253e7b0726df536186535e116a76cb0c04b928c8c7ea17a.jpg", + "table_caption": [ + "Table 7. Effect of two attention modules in the proposed method." + ], + "table_footnote": [], + "table_body": "
MethodFrameworkGPU MemFPSTimeAP
BCNetCNN4G8.34h23.1
BaselineTransformer9G6.56h22.9
OursTransformer13G3.78h39.4
", + "bbox": [ + 532, + 704, + 864, + 765 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 8. Comparison of computational cost and the performance. Time means the training time.", + "bbox": [ + 496, + 773, + 888, + 801 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4. Computational Cost", + "text_level": 1, + "bbox": [ + 500, + 816, + 691, + 832 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Tab. 8 compares the computational cost. The ResNet50-FPN backbone is used for all methods. The FPS is the average of all images in the validation dataset. Compared to other methods, our method exhibits superior performance at", + "bbox": [ + 496, + 839, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "23511", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "the expense of higher computational cost due to the use of Transformer framework.", + "bbox": [ + 76, + 90, + 470, + 122 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Limitation and Conclusion", + "text_level": 1, + "bbox": [ + 76, + 137, + 326, + 152 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Limitations of this paper include the consideration of only one scenario, shopping, and a high computational cost of the proposed method. Future research should aim to expand the dataset to include other scenarios and develop a more efficient network that incorporates additional information such as 3D models from MUVA. As for the conclusion, this paper introduces a novel task called multi-view amodal instance segmentation (MAIS) in the shopping scenario. To facilitate research in this area, a new synthetic dataset, MUVA, is introduced along with a proposed method that utilizes multi-view information.", + "bbox": [ + 75, + 162, + 472, + 329 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgments", + "text_level": 1, + "bbox": [ + 76, + 345, + 235, + 362 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work was partially supported by the Natural Science Foundation of China under contract 62088102. This work was also partially supported by Qualcomm. We also acknowledge High-Performance Computing Platform of Peking University for providing computational resources.", + "bbox": [ + 76, + 371, + 468, + 446 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 463, + 173, + 478 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Seunghyeok Back, Joosoon Lee, Taewon Kim, Sangjun Noh, Raeyoung Kang, Seongho Bak, and Kyoobin Lee. Unseen object amodal instance segmentation via hierarchical occlusion modeling. In International Conference on Robotics and Automation, pages 5085-5092, 2022.", + "[2] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 213-229, 2020.", + "[3] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1290–1299, 2022.", + "[4] Angela Dai, Angel X Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. ScanNet: Richly-annotated 3D reconstructions of indoor scenes. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5828-5839, 2017.", + "[5] Kaiwen Duan, Song Bai, Lingxi Xie, Honggang Qi, Qingming Huang, and Qi Tian. CenterNet: Keypoint triplets for object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6569-6578, 2019.", + "[6] Kiana Ehsani, Roozbeh Mottaghi, and Ali Farhadi. SeGAN: Segmenting and generating the invisible. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6144-6153, 2018." + ], + "bbox": [ + 86, + 488, + 468, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[7] Patrick Follmann, Tobias Bottger, Philipp Hartinger, Rebecca Konig, and Markus Ulrich. MVtec D2S: Densely segmented supermarket dataset. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 569-585, 2018.", + "[8] Patrick Follmann, Rebecca König, Philipp Hartinger, Michael Klostermann, and Tobias Böttger. Learning to see the invisible: End-to-end trainable amodal instance segmentation. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1328-1336, 2019.", + "[9] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the KITTI vision benchmark suite. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3354-3361, 2012.", + "[10] Ishaan Gulrajani and David Lopez-Paz. In search of lost domain generalization. In International Conference on Learning Representations, 2021.", + "[11] Kaiming He, Georgia Gkioxari, Piotr Dólar, and Ross Girshick. Mask R-CNN. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2961-2969, 2017.", + "[12] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016.", + "[13] Yuan-Ting Hu, Hong-Shuo Chen, Kexin Hui, Jia-Bin Huang, and Alexander G Schwing. SAIL-VOS: Semantic amodal instance level video object segmentation - a synthetic dataset and baselines. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3105-3115, 2019.", + "[14] Yuan-Ting Hu, Jiahong Wang, Raymond A. Yeh, and Alexander G. Schwing. SAIL-VOS 3D: A synthetic dataset and baselines for object detection and 3D mesh reconstruction from video data. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops, pages 3359-3369, 2021.", + "[15] Xueying Jiang, Jiaxing Huang, Sheng Jin, and Shijian Lu. Domain generalization via balancing training difficulty and model capability. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2023.", + "[16] Lei Ke, Yu-Wing Tai, and Chi-Keung Tang. Deep occlusion-aware instance segmentation with overlapping bilayers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4019–4028, 2021.", + "[17] Youngwan Lee and Jongyoul Park. CenterMask: Realtime anchor-free instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13906-13915, 2020.", + "[18] Ke Li, Bharath Hariharan, and Jitendra Malik. Iterative instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3659-3667, 2016.", + "[19] Ke Li and Jitendra Malik. Amodal instance segmentation. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 677-693, 2016." + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "23512", + "bbox": [ + 478, + 944, + 519, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[20] Zhixuan Li, Ruohua Shi, Tiejun Huang, and Tingting Jiang. OAFormer: Learning occlusion distinguishable feature for amodal instance segmentation. In International Conference on Acoustics, Speech, and Signal Processing, pages 1-5, 2023.", + "[21] Zhixuan Li, Weining Ye, Tingting Jiang, and Tiejun Huang. 2D amodal instance segmentation guided by 3D shape prior. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 165-181, 2022.", + "[22] Zhixuan Li, Weining Ye, Tingting Jiang, and Tiejun Huang. GIN: Generative invariant shape prior for amodal instance segmentation. In IEEE Transactions on Multimedia, 2023.", + "[23] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dálár, and C Lawrence Zitnick. Microsoft COCO: Common objects in context. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 740-755, 2014.", + "[24] Huan Ling, David Acuna, Karsten Kreis, Seung Wook Kim, and Sanja Fidler. Variational amodal object completion. In Advances in Neural Information Processing Systems, pages 16246-16257, 2020.", + "[25] D. Martin, C. Fowlkes, D. Tal, and J. Malik. A database of human segmented natural images and its application to evaluating segmentation algorithms and measuring ecological statistics. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 416-423, 2001.", + "[26] Sida Peng, Wen Jiang, Huaijin Pi, Xiuli Li, Hujun Bao, and Xiaowei Zhou. Deep snake for real-time instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020.", + "[27] Lu Qi, Li Jiang, Shu Liu, Xiaoyong Shen, and Jiaya Jia. Amodal instance segmentation with KINS dataset. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3014-3023, 2019.", + "[28] Mennatullah Siam, Sara Elkerdawy, Martin Jagersand, and Senthil Yogamani. Deep semantic segmentation for automated driving: Taxonomy, roadmap and challenges. In IEEE International Conference on Intelligent Transportation Systems, pages 1-8, 2017.", + "[29] Xiaolin Song, Kaili Zhao, Wen-Sheng Chu, Honggang Zhang, and Jun Guo. Progressive refinement network for occluded pedestrian detection. In Proceedings of the IEEE/CVF European Conference on Computer Vision, 2020.", + "[30] Zhi Tian, Chunhua Shen, and Hao Chen. Conditional convolutions for instance segmentation. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 282-298, 2020.", + "[31] Gül Varol, Javier Romero, Xavier Martin, Naureen Mahmood, Michael Black, Ivan Laptev, and Cordelia Schmid. Learning from synthetic humans. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4627-4635, 2017.", + "[32] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Advances in Neural Information Processing Systems, pages 5998-6008, 2017." + ], + "bbox": [ + 78, + 90, + 468, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[33] Yuting Xiao, Yanyu Xu, Ziming Zhong, Weixin Luo, Jiawei Li, and Shenghua Gao. Amodal segmentation based on visible region segmentation and shape prior. In Proceedings of the AAAI Conference on Artificial Intelligence, pages 2995-3003, 2021.", + "[34] Jin Xie, Yanwei Pang, M. H. Khan, Rao Muhammad Anwer, Fahad Shahbaz Khan, and Ling Shao. Mask-guided attention network and occlusion-sensitive hard example mining for occluded pedestrian detection. IEEE Transactions on Image Processing, 30:3872-3884, 2021.", + "[35] Xiaohang Zhan, Xingang Pan, Bo Dai, Ziwei Liu, Dahua Lin, and Chen Change Loy. Self-supervised scene de- occlusion. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3784- 3792, 2020.", + "[36] Shifeng Zhang, Longyin Wen, Xiao Bian, Zhen Lei, and S. Li. Occlusion-aware R-CNN: Detecting pedestrians in a crowd. In Proceedings of the IEEE/CVF European Conference on Computer Vision, 2018.", + "[37] Tao Zhang, Shiqing Wei, and Shunping Ji. E2EC: An end-to-end contour-based method for high-quality high-speed instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4443-4452, 2022.", + "[38] Ziheng Zhang, Anpei Chen, Ling Xie, Jingyi Yu, and Shenghua Gao. Learning semantics-aware distance map with semantics layering network for amodal instance segmentation. In Proceedings of the ACM International Conference on Multimedia, pages 2124-2132, 2019.", + "[39] Kaiyang Zhou, Yongxin Yang, Yu Qiao, and Tao Xiang. Domain generalization with mixstyle. In International Conference on Learning Representations, 2021.", + "[40] Yan Zhu, Yuandong Tian, Dimitris Metaxas, and Piotr Dólar. Semantic amodal segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1464-1472, 2017." + ], + "bbox": [ + 501, + 90, + 893, + 599 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "23513", + "bbox": [ + 478, + 944, + 519, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/4b78daa4-2084-48f2-bdbe-f8d1b9a4826f_model.json b/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/4b78daa4-2084-48f2-bdbe-f8d1b9a4826f_model.json new file mode 100644 index 0000000000000000000000000000000000000000..4d06194f22d916d1a0b619a3d948a5983476a6a8 --- /dev/null +++ b/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/4b78daa4-2084-48f2-bdbe-f8d1b9a4826f_model.json @@ -0,0 +1,1914 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.12, + 0.13, + 0.852, + 0.177 + ], + "angle": 0, + "content": "MUVA: A New Large-Scale Benchmark for Multi-view Amodal Instance Segmentation in the Shopping Scenario" + }, + { + "type": "text", + "bbox": [ + 0.227, + 0.203, + 0.741, + 0.24 + ], + "angle": 0, + "content": "Zhixuan Li\\(^{1}\\) Weining Ye\\(^{1}\\) Juan Terven\\(^{2}\\) Zachary Bennett\\(^{2}\\) Ying Zheng\\(^{2}\\) Tingting Jiang\\(^{1,*}\\) Tiejun Huang\\(^{1,3}\\)" + }, + { + "type": "text", + "bbox": [ + 0.128, + 0.242, + 0.842, + 0.275 + ], + "angle": 0, + "content": "\\(^{1}\\) National Engineering Research Center of Visual Technology, National Key Laboratory for Multimedia Information Processing, School of Computer Science, Peking University, Beijing 100871, China" + }, + { + "type": "text", + "bbox": [ + 0.34, + 0.276, + 0.631, + 0.291 + ], + "angle": 0, + "content": "\\(^{2}\\) AiFi Inc., California 94010, United States" + }, + { + "type": "text", + "bbox": [ + 0.226, + 0.293, + 0.746, + 0.346 + ], + "angle": 0, + "content": "3 Beijing Academy of Artificial Intelligence, Beijing 100084, China {zhixuanli,ywning}@pku.edu.cn, {juan,zachary}@aifi.com, yingz@alumni.gsb.stanford.edu, {ttjiang,tjhuang}@pku.edu.cn" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.38, + 0.314, + 0.396 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.412, + 0.474, + 0.745 + ], + "angle": 0, + "content": "Amodal Instance Segmentation (AIS) endeavors to accurately deduce complete object shapes that are partially or fully occluded. However, the inherent ill-posed nature of single-view datasets poses challenges in determining occluded shapes. A multi-view framework may help alleviate this problem, as humans often adjust their perspective when encountering occluded objects. At present, this approach has not yet been explored by existing methods and datasets. To bridge this gap, we propose a new task called Multi-view Amodal Instance Segmentation (MAIS) and introduce the MUVA dataset, the first MUlti-View AIS dataset that takes the shopping scenario as instantiation. MUVA provides comprehensive annotations, including multi-view amodal/visible segmentation masks, 3D models, and depth maps, making it the largest image-level AIS dataset in terms of both the number of images and instances. Additionally, we propose a new method for aggregating representative features across different instances and views, which demonstrates promising results in accurately predicting occluded objects from one viewpoint by leveraging information from other viewpoints. Besides, we also demonstrate that MUVA can benefit the AIS task in real-world scenarios." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.77, + 0.21, + 0.787 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.796, + 0.47, + 0.857 + ], + "angle": 0, + "content": "The amodal instance segmentation (AIS) task aims to determine an object's entire shape, encompassing its visible and occluded components. AIS task is more challenging than the visible instance segmentation task [23, 11]" + }, + { + "type": "image", + "bbox": [ + 0.526, + 0.38, + 0.87, + 0.613 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.623, + 0.895, + 0.695 + ], + "angle": 0, + "content": "Figure 1. Comparison of the impact of ill-posed problems on amodal prediction in single-view and multi-view input settings. (a) In single-view input, ambiguity arises due to multiple candidates for the occluded object. (b) Multi-view input helps alleviate ambiguity and improves amodal prediction accuracy." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.895, + 0.798 + ], + "angle": 0, + "content": "as it lacks occluded region appearance. Despite its complexity, the AIS task has significant implications for various industrial applications that encounter occlusion problems, such as robotic arm grasping [1], pedestrian re-identification [34, 36, 29], automatic driving [27, 28], and self-checkout systems in supermarkets [8]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Although numerous datasets [19, 40, 8, 27, 13] and methods [19, 40, 8, 27, 13, 38, 33, 21] have been proposed since the AIS task was firstly introduced in 2016 by Li and Malik [19], current AIS datasets and methods rely on a single-view approach, suffering from the ill-posed problem. For example, as shown in Fig. 1(a), directly deducting" + }, + { + "type": "page_footnote", + "bbox": [ + 0.094, + 0.863, + 0.223, + 0.876 + ], + "angle": 0, + "content": "*Corresponding author" + }, + { + "type": "page_footnote", + "bbox": [ + 0.078, + 0.876, + 0.469, + 0.901 + ], + "angle": 0, + "content": "1The proposed MUVA dataset can be downloaded from this link: https://zhixuanli.github.io/project_2023_ICCVMUVA." + }, + { + "type": "list", + "bbox": [ + 0.078, + 0.863, + 0.469, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "23504" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.471, + 0.198 + ], + "angle": 0, + "content": "the complete shape from a single-view image is extremely challenging due to the presence of occluded regions with multiple potential candidates. This is because distinct objects can share the same visible appearance but differ in shape within the occluded region. However, as shown in Fig. 1(b), humans tend to observe occluded objects from multiple angles to obtain accurate predictions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.2, + 0.47, + 0.336 + ], + "angle": 0, + "content": "Inspired by this observation, this paper proposes a novel task called MAIS (Multi-view Amodal Instance Segmentation), which predicts amodal segmentations through multiple viewpoints. The task is designed for real-world applications, under the assumption that the number of viewpoints and field of vision is limited, and objects in the scene are closely distributed with reasonable occlusion. These assumptions contribute to the difficulty and practical significance of the MAIS task." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.339, + 0.471, + 0.807 + ], + "angle": 0, + "content": "To study the MAIS task, creating a multi-view AIS dataset is essential. However, annotating multi-view data based on existing or newly collected real-world data involve significant efforts and may not be accurate in identifying shapes of occluded regions. This is because manually annotated amodal masks in real-world datasets are often inaccurate and inconsistent due to the varying shape prior knowledge of annotators, as shown in Fig. 2 (copied from [40]). Therefore, using a synthetic approach would be more precise and controllable. To create a synthetic dataset, one option is to build upon existing synthetic AIS datasets [6, 13, 14]. However, these datasets lack high-quality 3D models and sufficient occlusion. To overcome the limitation, we propose to create a new synthetic dataset comprising reconstructed high-quality 3D models and sufficient occlusion by controlling the distribution of objects. As an initial step in exploring the MAIS task, we limit our dataset construction to a single scenario. Specifically, the shopping scenario is selected due to its potential for multiple camera arrangements and its tendency for severe occlusion when goods are piled up. Consequently, we introduce MUVA, a novel MUlti-View Amodal Instance Segmentation dataset. The dataset creation process follows a standard three-step approach. Initially, 3D artists construct models from images collected from on-sale items. Next, 3D models are then selected and placed in a 3D scene with careful compositions to control the occlusion degree. Finally, multi-view images are captured by six simulated cameras to simulate a real-world self-checkout setting. Each image is extensively annotated with visible/amodal segmentation masks, depth maps, occlusion orders, and 3D models." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.47, + 0.902 + ], + "angle": 0, + "content": "To our best knowledge, MUVA is the first and only multi-view AIS dataset currently available. Unlike real-world-based AIS datasets [19, 40, 8, 27], MUVA provides precise annotations in the occluded region due to its synthetic nature and known ground-truth 3D models. Besides, MUVA is also the largest image-level AIS dataset in terms" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.697, + 0.107 + ], + "angle": 0, + "content": "of both images and instances." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.11, + 0.892, + 0.248 + ], + "angle": 0, + "content": "To exploit the multi-view information in MUVA, we introduce MASFormer, a novel method that aggregates information across different views and instances. Through comparative experiments with existing single-view-based AIS methods, we demonstrate that MASFormer significantly outperforms these methods by effectively utilizing multiview information. Additionally, our approach can accurately predict objects that are severely occluded from one angle by incorporating information from other angles." + }, + { + "type": "image", + "bbox": [ + 0.525, + 0.267, + 0.868, + 0.322 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.33, + 0.892, + 0.358 + ], + "angle": 0, + "content": "Figure 2. Two examples of COCOA [40] dataset, displaying multiple annotated occluded regions by different annotators." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.38, + 0.892, + 0.562 + ], + "angle": 0, + "content": "Our contributions are summarized as follows: 1) A new task named MAIS is proposed to explore the AIS task under the multi-view setting for alleviating the ill-posed problem in the AIS task. 2) A novel dataset named MUVA is proposed for the MAIS task in the multi-view setting for shopping scenarios. To our best knowledge, MUVA is the first AIS dataset under the multi-view setting. 3) A new method named MASFormer is proposed to collect both view-level and instance-level information for solving the ill-posed problem in the AIS task. The experimental results show the efficiency of the multi-view setting over the single-view approach." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.588, + 0.642, + 0.604 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.617, + 0.845, + 0.633 + ], + "angle": 0, + "content": "2.1. Amodal Instance Segmentation Datasets" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.644, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Various single-view-based AIS datasets have been proposed, including the image and video levels. (1) For the image level, most of the datasets are re-annotated manually based on the existing datasets for the visible instance segmentation (VIS) [5, 17, 30] task. For example, COCOA [40, 8], BSDSA [40], KINS [27] and D2SA [8] are extended based on the VIS datasets, including COCO [23], BSDS [25], KITTI [9] and D2S [7]. However, human annotation of occluded regions in image-level datasets may lack accuracy and consistency due to variations in the annotator's perception of amodal shape. Besides, DYCE [6] is a synthetic dataset for indoor furniture. (2) For the video level, two synthetic datasets, SAIL-VOS [13] and SAIL-VOS 3D [14] have been generated based on the GTA 3D game, containing daily-life scenes. Compared to video-level datasets with temporal consistency, MUVA exhibits higher shape variability across different viewpoints." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "23505" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.129, + 0.09, + 0.845, + 0.287 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.297, + 0.895, + 0.352 + ], + "angle": 0, + "content": "Figure 3. The pipeline of dataset generation. (a) For each object, 2D images are captured from up, down, left, right, front, and back, respectively. Then 3D artists use the collected images to reconstruct the 3D models. (b) For each scene, 3D models are randomly selected and placed with different amounts and orientations. (c) For each scene, six views are used to capture the data, including the RGB images and various annotations." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.375, + 0.426, + 0.39 + ], + "angle": 0, + "content": "2.2. Amodal Instance Segmentation Methods" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.4, + 0.473, + 0.763 + ], + "angle": 0, + "content": "AIS methods employ various cues for amodal completion and can be categorized into three types based on relevant literature. First, numerous methods are adapted from VIS methods. Li and Malik [19] use Iterative Instance Segmentation [18] to solve the amodal problem. ORCNN [8] extends Mask-RCNN for simultaneous visible and amodal segmentations. ASN [27] learns features with a proposed multi-level aggregation module. OAFformer [20] proposes to learn the occlusion discriminative queries with a transformer-base network. Second, some studies utilize the relative occlusion order between objects, including SLN [38] predicts and combines the relative orders, and Deocclusion [35] employs a self-training method to learn an ordering map for guiding the amodal completion. Third, some studies use the shape prior knowledge to help infer the shape of the occluded region, such as Amodal-VAE [24], ShapeDict [33], GIN [22] and A3D [21]. However, the multi-view information is not utilized in existing methods due to the absence of a suitable dataset. Based on the proposed MUVA dataset, this paper presents a 2D approach to leverage multi-view knowledge. Instead of using sophisticated 3D approaches like reconstruction, our 2D approach can be easily applicable to real-world scenarios without requiring 3D supervision signals." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.783, + 0.405, + 0.799 + ], + "angle": 0, + "content": "3. MUVA: Multi-view Amodal Dataset" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.47, + 0.903 + ], + "angle": 0, + "content": "MUVA comprises 1,801 distinct 3D objects reconstructed from multi-view photos. These objects are utilized to fabricate 4,401 scenes with diverse object placements. 26,406 RGB images are then produced from six cameras, each from differing viewpoints. The dataset includes thorough annotations, such as depth maps, 3D mod" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.375, + 0.892, + 0.421 + ], + "angle": 0, + "content": "els, and amodal/visible masks. The dataset split of MUVA, including train, validation and test, are shown in the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.433, + 0.669, + 0.447 + ], + "angle": 0, + "content": "3.1. Dataset Contents" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.456, + 0.892, + 0.775 + ], + "angle": 0, + "content": "The contents of MUVA including images and corresponding annotations are introduced below. RGB images are captured from each camera view with a resolution of \\(1920 \\times 1080\\). The high-quality 3D reconstructed models lead to final rendered RGB images with rich scene details and high visual quality. Six types of annotations are available for each RGB image. (1) The segmentation annotations of instances contain both visible and amodal instance masks. These are generated by the 3D simulation software, resulting in higher accuracy compared to manual annotations. Moreover, the occluded region mask annotations are more precise compared to human-annotated amodal masks which may vary between annotators. (2) Depth maps are produced to reflect the value of each pixel with regard to its distance from the relevant camera to the 3D object. The depth map registers distance for visible regions exclusively, excluding amodal regions. (3) The occlusion order specifies the list of other objects occluded by this one. (4) Accompanying high-quality 3D models are included. (5) The bounding boxes and area of both visible and amodal masks derived from corresponding masks are provided." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.786, + 0.688, + 0.8 + ], + "angle": 0, + "content": "3.2. Dataset Generation" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.81, + 0.892, + 0.855 + ], + "angle": 0, + "content": "A universal pipeline is designed to generate the synthetic dataset MUVA in three stages: building 3D models, placing 3D models, and capturing data, as illustrated in Fig. 3." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "3D Model Building. In this stage, 3D models are created as the foundation for the 3D scene, as presented in Fig. 3 (a). This stage contains two steps: (1) capturing six differ" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.946, + 0.521, + 0.957 + ], + "angle": 0, + "content": "23506" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.102, + 0.092, + 0.872, + 0.285 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.295, + 0.895, + 0.325 + ], + "angle": 0, + "content": "Figure 4. The histogram of the number of instances for four parent categories (bags, others, bottles, boxes) and corresponding subcategories. Non-rigid categories are noted with star stripes. Best viewed in color." + }, + { + "type": "table", + "bbox": [ + 0.11, + 0.334, + 0.866, + 0.481 + ], + "angle": 0, + "content": "
DatasetPublicationData TypeMultiple Views# Image# InstanceScenarioSynthetic or Real3D ModelDepth# CategoriesResolution (pixels)
SAIL-VOS [13]CVPR'19video-111,6541,896,295daily lifesynthetic-✓1621M
SAIL-VOS 3D [14]CVPR'21video-237,6113,460,213daily lifesynthetic✓✓1781M
COCOA [40]CVPR'17image-5,00046,314daily lifereal--N/A0.28M
BSDSA [40]CVPR'17image-5003,739daily lifereal--N/A0.15M
DYCE [6]CVPR'18image-5,50085,975daily lifesynthetic--791M
KINS [27]CVPR'19image-14,991190,626streetreal--80.47M
D2SA [8]WACV'19image-5,60028,720shoppingreal--603M
COCOA-cls [8]WACV'19image-3,50110,562daily lifereal--800.28M
MUVAN/Aimage✓26,406198,573shoppingsynthetic✓✓202M
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.489, + 0.893, + 0.518 + ], + "angle": 0, + "content": "Table 1. Comparison with existing amodal instance segmentation datasets. # means the number of this item. Bold numbers denote the largest one in each column among image-level datasets." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.542, + 0.471, + 0.634 + ], + "angle": 0, + "content": "ent images of each object to provide adequate information for 3D reconstruction, and (2) utilizing MAYA, a 3D modeling software, to reconstruct and manually refine the 3D objects iteratively by 3D artists. This process results in the reconstruction of 1801 distinct 3D objects, each with reconstructed shape and texture." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.644, + 0.473, + 0.903 + ], + "angle": 0, + "content": "3D Model Placing. This stage involves generating 3D scenes by selecting and placing 3D object models. It comprises two steps: 3D model selection and placement, as depicted in Fig. 3 (b). First, a shelf is created as a platform for scene construction, and 3D models are randomly chosen from those reconstructed in the previous stage. Second, placement settings, including object number, orientation, and position, are varied randomly to enhance diversity. The number of objects can range from less than 10 to more than 10, and their upright or flat placement is randomized. Object positions are also randomized, ensuring they are within the shelf's range. Finally, Unity3D software is used to render the scene. The physical simulation utilizes non-deformable 3D models with collision detection to prevent object penetration. The scenes were illuminated uniformly and gravity was applied to mimic realistic conditions. Creating all 1801 3D models required approximately" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.542, + 0.895, + 0.587 + ], + "angle": 0, + "content": "600 hours with a 20-minute time frame for each model. The cost of generating the models totaled approximately 15,000 USD at a rate of 25 USD per hour for each 3D artist." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.589, + 0.895, + 0.679 + ], + "angle": 0, + "content": "Data Capture. The simulated scene depicted in Fig. 3 (c) provides various types of data for sampling. Six cameras are positioned in the front to capture sparse views and simulate the self-checkout setting, ensuring the applicability of MUVA to real-life scenarios. For each view, RGB images and numerous annotations are generated." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.681, + 0.895, + 0.727 + ], + "angle": 0, + "content": "The above dataset generation pipeline is adaptable for creating datasets for other vision tasks, such as indoor 3D reconstruction [4] and person re-identification [31]." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.74, + 0.67, + 0.755 + ], + "angle": 0, + "content": "3.3. Dataset Statistics" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.895, + 0.903 + ], + "angle": 0, + "content": "MUVA dataset comprises 26,406 images with 198,573 instances categorized into four parent categories (bags, bottles, boxes, and others), and 20 sub-categories that include both rigid and non-rigid objects. The instance ratio of each category is presented in Fig. 4. The dataset contains \\(27.41\\%\\) non-rigid objects, such as the \"Plastic Bag,\" which provides shape variations. The proposed dataset includes high-resolution images of \\(1920 \\times 1080\\) pixels, providing rich details of the objects' edges and surfaces." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "23507" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.129, + 0.104, + 0.845, + 0.293 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.307, + 0.895, + 0.351 + ], + "angle": 0, + "content": "Figure 5. Overall architecture of our method. There are two stages in our method, including the Feature Extraction Stage and the Multi-view Aggregation Stage. The first stage aims to extract the features of each instance from all views. The second stage utilizes the relationship of features at the instance level and view level, respectively, to generate accurate predictions." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.373, + 0.387, + 0.39 + ], + "angle": 0, + "content": "3.4. Comparison with Existing Datasets" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.396, + 0.474, + 0.624 + ], + "angle": 0, + "content": "Tab. 1 presents a comparison between MUVA and other AIS datasets, including video and image-level datasets such as COCOA [40], BSDSA [40], DYCE [6], KINS [27], D2SA [8] and COCOA-cls [8]. MUVA stands out as the only dataset specifically designed for the multi-view AIS task and the only synthetic image-level dataset that provides 3D models. The 3D models used to build the dataset are publicly available to support new methods for the AIS task. Additionally, MUVA and D2SA are the only two datasets for the shopping scenario. MUVA's synthetic nature leads to consistent and higher-quality annotations than human-annotated datasets. Moreover, MUVA has the largest number of images and instances among image-level datasets, and is the only dataset at the image level that contains depth maps, which can potentially help with the AIS task." + }, + { + "type": "table", + "bbox": [ + 0.113, + 0.637, + 0.445, + 0.727 + ], + "angle": 0, + "content": "
Datasetsimplicity ↓convexity ↓
visibleamodalvisibleamodal
BSDS-A0.7180.8340.6160.643
COCO-A0.7460.8560.6580.685
KINS0.7090.8300.6100.639
MUVA0.9590.8010.9230.963
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.735, + 0.47, + 0.778 + ], + "angle": 0, + "content": "Table 2. Complexity is evaluated through simplicity and convexity metrics. Small values of these metrics indicate a complex dataset. A circle shape yields the maximum value of 1.0 for both metrics." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Shape Complexity. To assess the shape complexity of mask annotations contained in MUVA, metrics proposed by COCOA [40] is used. These metrics include convexity and simplicity for both visible and amodal masks. As shown in Tab. 2, MUVA has the lowest shape simplicity (0.801) and the highest convexity (0.963) of amodal masks. The high convexity can be attributed to the presence of goods such" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.373, + 0.895, + 0.45 + ], + "angle": 0, + "content": "as bags, bottles, and boxes, which possess naturally convex shapes. Conversely, the low simplicity confirms that the shapes within MUVA are complex. For instance, a plastic bag with zigzagged boundaries exhibits high convexity but low simplicity." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.459, + 0.634, + 0.475 + ], + "angle": 0, + "content": "3.5. Applications" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.482, + 0.895, + 0.633 + ], + "angle": 0, + "content": "MUVA provides diverse annotations that can be used for multiple research tasks. For example, using instance IDs from different viewpoints can lead to a new task of multi-view amodal instance segmentation (MAIS), which involves matching and segmenting the same instance from multiple viewpoints. High-quality 3D models can be used for single/multiple-view 3D reconstruction. The provided relative depth order annotation allows for occlusion order prediction. Finally, the depth map from the object to the camera can be utilized for depth estimation." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.647, + 0.591, + 0.661 + ], + "angle": 0, + "content": "4. Method" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.672, + 0.894, + 0.764 + ], + "angle": 0, + "content": "This paper focuses on the newly formulated multi-view amodal instance segmentation (MAIS) task. This section proposes a network designed for the MAIS task, named Multi-view Amodal Segmentation Transformer (MAS-Former). The task definition, overall architecture, and the proposed new modules are introduced in the following." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.772, + 0.611, + 0.787 + ], + "angle": 0, + "content": "4.1. Overview" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.892, + 0.841 + ], + "angle": 0, + "content": "Problem Definition. Given \\(N\\) input images from \\(N\\) viewpoints, the MAIS task aims to predict \\(K\\) instance-level segmentation masks for interested objects in each image." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.841, + 0.894, + 0.901 + ], + "angle": 0, + "content": "Overall Architecture. The whole pipeline of the proposed method contains two stages, including the Feature Extraction Stage (FES) and the Multi-view Aggregation Stage (MAS). (1) The FES extracts features of each instance" + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "23508" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.08, + 0.092, + 0.468, + 0.181 + ], + "angle": 0, + "content": "from all angles. (2) The MAS takes the instances' feature from FES as input and optimizes from two aspects, including aggregating all instances' features of the same view and all views' features of the same instance. Finally, the amodal instance predictions of objects in all images are generated after fusion." + }, + { + "type": "title", + "bbox": [ + 0.08, + 0.193, + 0.304, + 0.209 + ], + "angle": 0, + "content": "4.2. Feature Extraction Stage" + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.217, + 0.468, + 0.396 + ], + "angle": 0, + "content": "This stage aims to extract features from all views simultaneously. As shown in Fig. 5, the Backbone takes for \\(N\\) images as input and extracts representative features for \\(K\\) instances, including low-level structural details and high-level semantic information. Next, the CNN Decoder up-samples the representative features and generates multilevel features containing all objects' information. Then a Transformer Decoder is employed to output features \\(F_{FES}\\) corresponding to all objects in all views. Bipartite matching [2] is used to find the correspondence between predictions and supervisions, to specify the view id and instance id of each feature." + }, + { + "type": "title", + "bbox": [ + 0.08, + 0.408, + 0.341, + 0.425 + ], + "angle": 0, + "content": "4.3. Multi-view Aggregation Stage" + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.432, + 0.468, + 0.492 + ], + "angle": 0, + "content": "As shown in Fig. 5, this stage aims to enhance the extracted features \\( F_{FES} \\) from two aspects, including view-level and instance-level. Two branches are designed for the two aspects, respectively." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.493, + 0.468, + 0.779 + ], + "angle": 0, + "content": "View-level Aggregation. This branch aims to utilize the relationship between features of all instances in the same view for enhancing each instance's feature quality. Firstly, for input features \\( F_{FES} \\) including all objects in all views, an View Feature Grouping module takes features of the same view into the same group. Then the View-level Attention module learns the correlation between all instances' features in the same view. Finally, the feature of each instance is enhanced by integrating all correlated instances' features in the same view. Here the correlation between different features is computed by cosine similarity. And the self-attention [32] is used to construct this module. Please refer to our supplementary material for detailed explanations of the network. Besides, this module requires objects in different views could be identified and matched. To achieve this, for each instance, both the view id and the instance id are predicted by the network and supervised by using the bipartite matching [2] to match between the prediction and ground truth." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.78, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Instance-level Aggregation. This module aims to use features of the same instance in all views to improve the feature quality of each instance. First, the Instance Feature Grouping module takes features of the same instance across all views to the same group. Next, for each group, the Instance-level Attention module learns correlations between features of the same instance in different views and integrates associated features by using the self-attention [32]" + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.093, + 0.582, + 0.105 + ], + "angle": 0, + "content": "mechanism." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.108, + 0.892, + 0.183 + ], + "angle": 0, + "content": "Finally, a CNN-based fuse layer is used to merge the output features of two branches for the final prediction of amodal masks. With the aggregation of two branches, the feature representations of all instances can be enhanced, and more precise amodal segmentation results can be obtained." + }, + { + "type": "title", + "bbox": [ + 0.504, + 0.201, + 0.63, + 0.218 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.227, + 0.892, + 0.318 + ], + "angle": 0, + "content": "This section first compares the newly proposed method MASFormer with existing single-view-based state-of-the-art AIS methods on the proposed MUVA dataset. Then the ablation studies are conducted to show the effectiveness of amount and order for the input viewpoints and components of the proposed method." + }, + { + "type": "table", + "bbox": [ + 0.536, + 0.332, + 0.86, + 0.474 + ], + "angle": 0, + "content": "
MethodPublicationAPAP50AP75AR
Mask-RCNN [11]ICCV'1717.226.618.748.8
ORCNN [8]WACV'197.825.92.124.7
SLN [38]ACM MM'196.920.25.622.9
DeepSnake [26]CVPR'207.711.97.423.8
BCNet [16]CVPR'2123.128.925.040.9
ShapeDict [33]AAAI'219.936.01.327.8
E2EC [37]CVPR'2211.815.712.925.5
Baseline (1 view)CVPR'2217.826.118.029.2
Baseline (6 views)CVPR'2222.935.522.336.4
Ours (1 view)N/A25.638.025.641.2
Ours (6 views)N/A39.455.940.351.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.504, + 0.484, + 0.891, + 0.511 + ], + "angle": 0, + "content": "Table 3. Compared with state-of-the-art methods on MUVA. In each column, the best is in bold, and the second-best is underlined." + }, + { + "type": "table", + "bbox": [ + 0.52, + 0.542, + 0.879, + 0.619 + ], + "angle": 0, + "content": "
MethodResNet-50ResNet-101ResNeXt-101
MaskRCNN17.219.119.8
BCNet23.125.326.6
E2EC11.814.215.9
Ours (6 views)39.442.543.0
" + }, + { + "type": "table_caption", + "bbox": [ + 0.524, + 0.629, + 0.869, + 0.642 + ], + "angle": 0, + "content": "Table 4. Performance of methods with stronger backbones." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.659, + 0.892, + 0.9 + ], + "angle": 0, + "content": "Experimental Settings. The baseline method only contains the first stage FES in the proposed method MAS-Former, which is implemented following the video instance segmentation method Mask2Former [3] as an instantiation. The baseline method can take multi-view images as input and outputs amodal segmentation masks, the same as MAS-Former. ResNet-FPN-50 [12] is employed as the backbone for all methods. The results are evaluated using the AP and AR metric, commonly used to measure the precision and recall of prediction. For fairness, all experiments use the same training dataset of MUVA to train and the same validation dataset of MUVA to validate. The ground truth of all methods is the same, including the bounding boxes and masks for amodal and visible regions, image ids, and instance ids. The ground-truth camera viewpoint information and 3D models are not used for fairness." + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.946, + 0.518, + 0.957 + ], + "angle": 0, + "content": "23509" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.123, + 0.09, + 0.852, + 0.327 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.335, + 0.895, + 0.391 + ], + "angle": 0, + "content": "Figure 6. Visualization comparisons between BCNet [16] and ours on MUVA, trained with one viewpoint (1V) and six viewpoints (6V). For masks, different colors denote different instances, and the same instance in different angles has the same color. Red circles indicate regions should be focused. Zoom in for a better view. In the first and third columns, even if a bottle is severely occluded, it can be predicted accurately by our method. Moreover, our method trained with 6 views performs better than training with a single view." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.415, + 0.443, + 0.433 + ], + "angle": 0, + "content": "5.1. Multi-view Amodal Instance Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.443, + 0.471, + 0.549 + ], + "angle": 0, + "content": "Tab. 3 shows the comparison results of some existing AIS methods on MUVA. Several state-of-the-art methods designed for single-view datasets are compared. For baseline and the proposed method MASFormer, two kinds of input are used during training, one is a single view, and the other is six. Note that the amount of training data is the same for these two settings." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.554, + 0.471, + 0.902 + ], + "angle": 0, + "content": "We compare the results at three levels, including one-view, one vs. six views, and six-view levels. (1) As shown in Tab. 3, when only using one view for training, our proposed method MASFormer achieves the best performance \\((25.6\\% AP, 38.0\\% AP_{50}, 25.6\\% AP_{75}, 41.2\\% AR)\\) on all metrics. MASFormer outperforms the best performance of single-view-based methods with \\(2.7\\% AP, 2.0\\% AP_{50}, 0.6\\% AP_{75}\\), and \\(0.2\\% AR\\). The results demonstrate the effectiveness of the proposed view-level attention module, which can learn the relationship between different instances of the same view and improve the amodal prediction with the help of a learned relationship. (2) Both ours and the baseline method achieve better performance when using six views than one view for training. The results show that even with the same training data, using more views as input for training can improve the prediction. (3) When both methods use six views for training, our method can outperform the baseline method with \\(16.5\\%\\) AP. The results show the effectiveness of the proposed instance-level attention module, which learns and benefits from the relationship between different views of the same instance. Besides, the performance of methods with stronger backbones is shown in Tab. 4. Stronger backbones bring improvements for all" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.416, + 0.892, + 0.448 + ], + "angle": 0, + "content": "methods, while the proposed MASFormer still achieves the best performance. Qualitative results are shown in Fig. 6." + }, + { + "type": "table", + "bbox": [ + 0.511, + 0.459, + 0.89, + 0.524 + ], + "angle": 0, + "content": "
SettingTraining DatasetTesting DatasetAP
1D2SAtrainD2SAval63.5
2MUVAtrainD2SAval41.9
3D2SAtrain + MUVAtrainD2SAval68.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.533, + 0.894, + 0.59 + ], + "angle": 0, + "content": "Table 5. Performance of MASFormer evaluated on the validation set of D2SA dataset and trained with different combinations of source-domain datasets for training. For the two datasets, only data of overlapped categories are used." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.605, + 0.838, + 0.62 + ], + "angle": 0, + "content": "5.2. Generalization to Real-world Scenarios" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.629, + 0.892, + 0.674 + ], + "angle": 0, + "content": "In this section, we demonstrate the generalization ability of the proposed dataset and method on real-world scenarios under single-view and multi-view settings, respectively." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.675, + 0.893, + 0.901 + ], + "angle": 0, + "content": "Single-view Generalization. To validate generalization ability in real-world scenarios, the MUVA dataset is utilized under a single-view setting. To be specific, we employ settings of the domain generalization [39, 10, 15] task to evaluate the generalization ability of learning from a source domain, typically synthetic datasets, to out-of-distribution target domains like real-world datasets. Specifically, the MUVA synthetic dataset and real-world AIS dataset D2SA [8] are used in this study. D2SA contains 60 categories, of which 18 categories overlap with MUVA. More information about the category labels can be found in the supplementary material. The following experiments only consider data from the overlapping categories. Three settings were adopted as presented in Tab. 5. Firstly, MASFormer is trained and evaluated on the train and validation sets of" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "23510" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.198 + ], + "angle": 0, + "content": "D2SA datasets, demonstrating its ability to generalize well on real-world data. Secondly, MASFormer is trained on the synthetic MUVA dataset and evaluated on the real-world dataset D2SA, with results validating the generalizability of the synthetic MUVA dataset. Lastly, mixing D2SA and MUVA for training lead to a \\(4.9\\%\\) AP improvement, indicating the benefits of using MUVA in a real-world scenario." + }, + { + "type": "image", + "bbox": [ + 0.084, + 0.212, + 0.47, + 0.376 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.385, + 0.471, + 0.426 + ], + "angle": 0, + "content": "Figure 7. Qualitative results of a real-world case. Red circles indicate differences between ours and BCNet. Zoom in for a better view." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.439, + 0.47, + 0.635 + ], + "angle": 0, + "content": "Multi-view Generalization. Considering there is no existing multi-view real-world AIS dataset, we construct a real-world shopping scenario to obtain multi-view data for validating the generalization ability of the proposed dataset and method. Images are captured from the left, middle, and right sides, respectively. MASFormer trained with six views and BCNet are used. And the train set of MUVA is utilized for training. As shown in Fig. 7, MASFormer can obtain good amodal segmentation results, demonstrating the generalization ability of MUVA to real-world scenarios. Moreover, when compared with BCNet, MASFormer performs better consistently on all viewpoints, validating its potential for generalizing to the real-world scene." + }, + { + "type": "table", + "bbox": [ + 0.095, + 0.647, + 0.455, + 0.807 + ], + "angle": 0, + "content": "
Views Order# ViewsAPAP50AP75AR
N/A125.638.025.639.2
Fixed Order226.238.026.339.8
328.042.927.740.9
430.945.630.943.5
534.149.034.747.4
637.953.938.651.4
Random Order226.939.527.140.4
328.441.728.442.9
432.846.633.445.6
536.952.737.250.5
639.455.940.351.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.817, + 0.47, + 0.845 + ], + "angle": 0, + "content": "Table 6. Effect of fixing views input order and views amount. In each column, the best is in bold, and the second-best is underlined." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.851, + 0.231, + 0.868 + ], + "angle": 0, + "content": "5.3. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.471, + 0.901 + ], + "angle": 0, + "content": "We conducted ablation study experiments for MAS-Former, examining the impact of the number and order of" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.89, + 0.121 + ], + "angle": 0, + "content": "input viewpoints, the effectiveness of attention modules, and computational cost." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.122, + 0.892, + 0.422 + ], + "angle": 0, + "content": "Viewpoints Count and Order. Tab 6 presents some combinations of the number and order of input viewpoints used for training in the proposed MASFormer method. The same amount of training data is used for all experiments. Performance consistently improves as the number of input views increases, regardless of whether their order is fixed (rows # 2 to # 6) or random (rows # 7 to # 11). These results show that using more views for training can improve performance and multi-view data is crucial for amodal instance segmentation. When the number of input views is constant, the impact of the input views' order is analyzed below. As shown in Tab. 6, results of random input order outperform fixed order ones with the equal number of input views. For example, random order improves the \\(AP\\) metric with the following percentages compared to fixed order: \\(0.7\\%\\) (2 views), \\(0.4\\%\\) (3 views), \\(1.9\\%\\) (4 views), \\(2.8\\%\\) (5 views) and \\(1.5\\%\\) (6 views). Results show that randomizing input image ordering of various viewpoints leads to increased training sample distribution and improved effectiveness." + }, + { + "type": "table", + "bbox": [ + 0.531, + 0.435, + 0.869, + 0.507 + ], + "angle": 0, + "content": "
IndexView-levelInstance-levelAPAP50AP75AR
122.935.522.336.4
2✓28.743.128.341.6
3✓34.149.034.747.4
4✓✓39.455.940.351.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.516, + 0.885, + 0.53 + ], + "angle": 0, + "content": "Table 7. Effect of two attention modules in the proposed method." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.541, + 0.892, + 0.692 + ], + "angle": 0, + "content": "Attention Modules. Tab. 7 shows the ablation study of proposed attention modules proposed in our MASFormer method, using six input views with random order. The proposed view-level attention module improves \\(AP\\) performance from \\(22.9\\%\\) to \\(28.7\\%\\) by learning feature relationships within the same view. Instance-level attention module achieves an \\(11.2\\%\\) improvement by utilizing multi-view features of the same instance. Both attention modules combined result in a \\(39.4\\%\\) \\(AP\\) performance, surpassing individual settings." + }, + { + "type": "table", + "bbox": [ + 0.534, + 0.705, + 0.866, + 0.766 + ], + "angle": 0, + "content": "
MethodFrameworkGPU MemFPSTimeAP
BCNetCNN4G8.34h23.1
BaselineTransformer9G6.56h22.9
OursTransformer13G3.78h39.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.775, + 0.89, + 0.803 + ], + "angle": 0, + "content": "Table 8. Comparison of computational cost and the performance. Time means the training time." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.817, + 0.692, + 0.833 + ], + "angle": 0, + "content": "5.4. Computational Cost" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Tab. 8 compares the computational cost. The ResNet50-FPN backbone is used for all methods. The FPS is the average of all images in the validation dataset. Compared to other methods, our method exhibits superior performance at" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "23511" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.472, + 0.123 + ], + "angle": 0, + "content": "the expense of higher computational cost due to the use of Transformer framework." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.138, + 0.327, + 0.154 + ], + "angle": 0, + "content": "6. Limitation and Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.164, + 0.473, + 0.33 + ], + "angle": 0, + "content": "Limitations of this paper include the consideration of only one scenario, shopping, and a high computational cost of the proposed method. Future research should aim to expand the dataset to include other scenarios and develop a more efficient network that incorporates additional information such as 3D models from MUVA. As for the conclusion, this paper introduces a novel task called multi-view amodal instance segmentation (MAIS) in the shopping scenario. To facilitate research in this area, a new synthetic dataset, MUVA, is introduced along with a proposed method that utilizes multi-view information." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.346, + 0.236, + 0.363 + ], + "angle": 0, + "content": "Acknowledgments" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.372, + 0.47, + 0.448 + ], + "angle": 0, + "content": "This work was partially supported by the Natural Science Foundation of China under contract 62088102. This work was also partially supported by Qualcomm. We also acknowledge High-Performance Computing Platform of Peking University for providing computational resources." + }, + { + "type": "title", + "bbox": [ + 0.079, + 0.464, + 0.174, + 0.479 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.489, + 0.47, + 0.559 + ], + "angle": 0, + "content": "[1] Seunghyeok Back, Joosoon Lee, Taewon Kim, Sangjun Noh, Raeyoung Kang, Seongho Bak, and Kyoobin Lee. Unseen object amodal instance segmentation via hierarchical occlusion modeling. In International Conference on Robotics and Automation, pages 5085-5092, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.561, + 0.47, + 0.629 + ], + "angle": 0, + "content": "[2] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 213-229, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.632, + 0.47, + 0.701 + ], + "angle": 0, + "content": "[3] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1290–1299, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.703, + 0.47, + 0.771 + ], + "angle": 0, + "content": "[4] Angela Dai, Angel X Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. ScanNet: Richly-annotated 3D reconstructions of indoor scenes. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5828-5839, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.774, + 0.47, + 0.842 + ], + "angle": 0, + "content": "[5] Kaiwen Duan, Song Bai, Lingxi Xie, Honggang Qi, Qingming Huang, and Qi Tian. CenterNet: Keypoint triplets for object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6569-6578, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.845, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[6] Kiana Ehsani, Roozbeh Mottaghi, and Ali Farhadi. SeGAN: Segmenting and generating the invisible. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6144-6153, 2018." + }, + { + "type": "list", + "bbox": [ + 0.087, + 0.489, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.093, + 0.892, + 0.16 + ], + "angle": 0, + "content": "[7] Patrick Follmann, Tobias Bottger, Philipp Hartinger, Rebecca Konig, and Markus Ulrich. MVtec D2S: Densely segmented supermarket dataset. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 569-585, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.511, + 0.163, + 0.892, + 0.244 + ], + "angle": 0, + "content": "[8] Patrick Follmann, Rebecca König, Philipp Hartinger, Michael Klostermann, and Tobias Böttger. Learning to see the invisible: End-to-end trainable amodal instance segmentation. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1328-1336, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.511, + 0.247, + 0.892, + 0.314 + ], + "angle": 0, + "content": "[9] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the KITTI vision benchmark suite. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3354-3361, 2012." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.316, + 0.892, + 0.357 + ], + "angle": 0, + "content": "[10] Ishaan Gulrajani and David Lopez-Paz. In search of lost domain generalization. In International Conference on Learning Representations, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.358, + 0.892, + 0.412 + ], + "angle": 0, + "content": "[11] Kaiming He, Georgia Gkioxari, Piotr Dólar, and Ross Girshick. Mask R-CNN. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2961-2969, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.414, + 0.892, + 0.468 + ], + "angle": 0, + "content": "[12] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.47, + 0.892, + 0.551 + ], + "angle": 0, + "content": "[13] Yuan-Ting Hu, Hong-Shuo Chen, Kexin Hui, Jia-Bin Huang, and Alexander G Schwing. SAIL-VOS: Semantic amodal instance level video object segmentation - a synthetic dataset and baselines. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3105-3115, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.553, + 0.892, + 0.635 + ], + "angle": 0, + "content": "[14] Yuan-Ting Hu, Jiahong Wang, Raymond A. Yeh, and Alexander G. Schwing. SAIL-VOS 3D: A synthetic dataset and baselines for object detection and 3D mesh reconstruction from video data. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops, pages 3359-3369, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.637, + 0.892, + 0.691 + ], + "angle": 0, + "content": "[15] Xueying Jiang, Jiaxing Huang, Sheng Jin, and Shijian Lu. Domain generalization via balancing training difficulty and model capability. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.692, + 0.892, + 0.748 + ], + "angle": 0, + "content": "[16] Lei Ke, Yu-Wing Tai, and Chi-Keung Tang. Deep occlusion-aware instance segmentation with overlapping bilayers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4019–4028, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.749, + 0.894, + 0.803 + ], + "angle": 0, + "content": "[17] Youngwan Lee and Jongyoul Park. CenterMask: Realtime anchor-free instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13906-13915, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.804, + 0.892, + 0.858 + ], + "angle": 0, + "content": "[18] Ke Li, Bharath Hariharan, and Jitendra Malik. Iterative instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3659-3667, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.86, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[19] Ke Li and Jitendra Malik. Amodal instance segmentation. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 677-693, 2016." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.957 + ], + "angle": 0, + "content": "23512" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.161 + ], + "angle": 0, + "content": "[20] Zhixuan Li, Ruohua Shi, Tiejun Huang, and Tingting Jiang. OAFormer: Learning occlusion distinguishable feature for amodal instance segmentation. In International Conference on Acoustics, Speech, and Signal Processing, pages 1-5, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.165, + 0.47, + 0.22 + ], + "angle": 0, + "content": "[21] Zhixuan Li, Weining Ye, Tingting Jiang, and Tiejun Huang. 2D amodal instance segmentation guided by 3D shape prior. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 165-181, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.223, + 0.47, + 0.266 + ], + "angle": 0, + "content": "[22] Zhixuan Li, Weining Ye, Tingting Jiang, and Tiejun Huang. GIN: Generative invariant shape prior for amodal instance segmentation. In IEEE Transactions on Multimedia, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.268, + 0.47, + 0.337 + ], + "angle": 0, + "content": "[23] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dálár, and C Lawrence Zitnick. Microsoft COCO: Common objects in context. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 740-755, 2014." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.339, + 0.47, + 0.394 + ], + "angle": 0, + "content": "[24] Huan Ling, David Acuna, Karsten Kreis, Seung Wook Kim, and Sanja Fidler. Variational amodal object completion. In Advances in Neural Information Processing Systems, pages 16246-16257, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.397, + 0.47, + 0.467 + ], + "angle": 0, + "content": "[25] D. Martin, C. Fowlkes, D. Tal, and J. Malik. A database of human segmented natural images and its application to evaluating segmentation algorithms and measuring ecological statistics. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 416-423, 2001." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.469, + 0.47, + 0.525 + ], + "angle": 0, + "content": "[26] Sida Peng, Wen Jiang, Huaijin Pi, Xiuli Li, Hujun Bao, and Xiaowei Zhou. Deep snake for real-time instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.527, + 0.47, + 0.582 + ], + "angle": 0, + "content": "[27] Lu Qi, Li Jiang, Shu Liu, Xiaoyong Shen, and Jiaya Jia. Amodal instance segmentation with KINS dataset. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3014-3023, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.585, + 0.47, + 0.655 + ], + "angle": 0, + "content": "[28] Mennatullah Siam, Sara Elkerdawy, Martin Jagersand, and Senthil Yogamani. Deep semantic segmentation for automated driving: Taxonomy, roadmap and challenges. In IEEE International Conference on Intelligent Transportation Systems, pages 1-8, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.657, + 0.47, + 0.713 + ], + "angle": 0, + "content": "[29] Xiaolin Song, Kaili Zhao, Wen-Sheng Chu, Honggang Zhang, and Jun Guo. Progressive refinement network for occluded pedestrian detection. In Proceedings of the IEEE/CVF European Conference on Computer Vision, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.716, + 0.47, + 0.77 + ], + "angle": 0, + "content": "[30] Zhi Tian, Chunhua Shen, and Hao Chen. Conditional convolutions for instance segmentation. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 282-298, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.773, + 0.47, + 0.843 + ], + "angle": 0, + "content": "[31] Gül Varol, Javier Romero, Xavier Martin, Naureen Mahmood, Michael Black, Ivan Laptev, and Cordelia Schmid. Learning from synthetic humans. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4627-4635, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[32] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Advances in Neural Information Processing Systems, pages 5998-6008, 2017." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.092, + 0.895, + 0.161 + ], + "angle": 0, + "content": "[33] Yuting Xiao, Yanyu Xu, Ziming Zhong, Weixin Luo, Jiawei Li, and Shenghua Gao. Amodal segmentation based on visible region segmentation and shape prior. In Proceedings of the AAAI Conference on Artificial Intelligence, pages 2995-3003, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.164, + 0.895, + 0.232 + ], + "angle": 0, + "content": "[34] Jin Xie, Yanwei Pang, M. H. Khan, Rao Muhammad Anwer, Fahad Shahbaz Khan, and Ling Shao. Mask-guided attention network and occlusion-sensitive hard example mining for occluded pedestrian detection. IEEE Transactions on Image Processing, 30:3872-3884, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.234, + 0.895, + 0.302 + ], + "angle": 0, + "content": "[35] Xiaohang Zhan, Xingang Pan, Bo Dai, Ziwei Liu, Dahua Lin, and Chen Change Loy. Self-supervised scene de- occlusion. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3784- 3792, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.304, + 0.895, + 0.359 + ], + "angle": 0, + "content": "[36] Shifeng Zhang, Longyin Wen, Xiao Bian, Zhen Lei, and S. Li. Occlusion-aware R-CNN: Detecting pedestrians in a crowd. In Proceedings of the IEEE/CVF European Conference on Computer Vision, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.361, + 0.895, + 0.429 + ], + "angle": 0, + "content": "[37] Tao Zhang, Shiqing Wei, and Shunping Ji. E2EC: An end-to-end contour-based method for high-quality high-speed instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4443-4452, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.431, + 0.895, + 0.5 + ], + "angle": 0, + "content": "[38] Ziheng Zhang, Anpei Chen, Ling Xie, Jingyi Yu, and Shenghua Gao. Learning semantics-aware distance map with semantics layering network for amodal instance segmentation. In Proceedings of the ACM International Conference on Multimedia, pages 2124-2132, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.502, + 0.895, + 0.543 + ], + "angle": 0, + "content": "[39] Kaiyang Zhou, Yongxin Yang, Yu Qiao, and Tao Xiang. Domain generalization with mixstyle. In International Conference on Learning Representations, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.545, + 0.895, + 0.6 + ], + "angle": 0, + "content": "[40] Yan Zhu, Yuandong Tian, Dimitris Metaxas, and Piotr Dólar. Semantic amodal segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1464-1472, 2017." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.092, + 0.895, + 0.6 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "23513" + } + ] +] \ No newline at end of file diff --git a/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/4b78daa4-2084-48f2-bdbe-f8d1b9a4826f_origin.pdf b/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/4b78daa4-2084-48f2-bdbe-f8d1b9a4826f_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..46ab20fd6432b8a1360fd48aebe2901d376c2bc8 --- /dev/null +++ b/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/4b78daa4-2084-48f2-bdbe-f8d1b9a4826f_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:62e7ca7ca6acc284db9cca2c46546f829de5cce2f588fa67699e4475792c26d1 +size 7789968 diff --git a/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/full.md b/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/full.md new file mode 100644 index 0000000000000000000000000000000000000000..ea7069f2c8782be13984f39a477b761f7bfc0370 --- /dev/null +++ b/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/full.md @@ -0,0 +1,262 @@ +# MUVA: A New Large-Scale Benchmark for Multi-view Amodal Instance Segmentation in the Shopping Scenario + +Zhixuan Li $^{1}$ Weining Ye $^{1}$ Juan Terven $^{2}$ Zachary Bennett $^{2}$ Ying Zheng $^{2}$ Tingting Jiang $^{1,*}$ Tiejun Huang $^{1,3}$ + +$^{1}$ National Engineering Research Center of Visual Technology, National Key Laboratory for Multimedia Information Processing, School of Computer Science, Peking University, Beijing 100871, China + +$^{2}$ AiFi Inc., California 94010, United States + +3 Beijing Academy of Artificial Intelligence, Beijing 100084, China {zhixuanli,ywning}@pku.edu.cn, {juan,zachary}@aifi.com, yingz@alumni.gsb.stanford.edu, {ttjiang,tjhuang}@pku.edu.cn + +# Abstract + +Amodal Instance Segmentation (AIS) endeavors to accurately deduce complete object shapes that are partially or fully occluded. However, the inherent ill-posed nature of single-view datasets poses challenges in determining occluded shapes. A multi-view framework may help alleviate this problem, as humans often adjust their perspective when encountering occluded objects. At present, this approach has not yet been explored by existing methods and datasets. To bridge this gap, we propose a new task called Multi-view Amodal Instance Segmentation (MAIS) and introduce the MUVA dataset, the first MUlti-View AIS dataset that takes the shopping scenario as instantiation. MUVA provides comprehensive annotations, including multi-view amodal/visible segmentation masks, 3D models, and depth maps, making it the largest image-level AIS dataset in terms of both the number of images and instances. Additionally, we propose a new method for aggregating representative features across different instances and views, which demonstrates promising results in accurately predicting occluded objects from one viewpoint by leveraging information from other viewpoints. Besides, we also demonstrate that MUVA can benefit the AIS task in real-world scenarios. + +# 1. Introduction + +The amodal instance segmentation (AIS) task aims to determine an object's entire shape, encompassing its visible and occluded components. AIS task is more challenging than the visible instance segmentation task [23, 11] + +![](images/9b2be6dd5e1bed2e89f851c89adf672e90b2bebd49153de9e77dcb2dcc34349d.jpg) +Figure 1. Comparison of the impact of ill-posed problems on amodal prediction in single-view and multi-view input settings. (a) In single-view input, ambiguity arises due to multiple candidates for the occluded object. (b) Multi-view input helps alleviate ambiguity and improves amodal prediction accuracy. + +as it lacks occluded region appearance. Despite its complexity, the AIS task has significant implications for various industrial applications that encounter occlusion problems, such as robotic arm grasping [1], pedestrian re-identification [34, 36, 29], automatic driving [27, 28], and self-checkout systems in supermarkets [8]. + +Although numerous datasets [19, 40, 8, 27, 13] and methods [19, 40, 8, 27, 13, 38, 33, 21] have been proposed since the AIS task was firstly introduced in 2016 by Li and Malik [19], current AIS datasets and methods rely on a single-view approach, suffering from the ill-posed problem. For example, as shown in Fig. 1(a), directly deducting + +the complete shape from a single-view image is extremely challenging due to the presence of occluded regions with multiple potential candidates. This is because distinct objects can share the same visible appearance but differ in shape within the occluded region. However, as shown in Fig. 1(b), humans tend to observe occluded objects from multiple angles to obtain accurate predictions. + +Inspired by this observation, this paper proposes a novel task called MAIS (Multi-view Amodal Instance Segmentation), which predicts amodal segmentations through multiple viewpoints. The task is designed for real-world applications, under the assumption that the number of viewpoints and field of vision is limited, and objects in the scene are closely distributed with reasonable occlusion. These assumptions contribute to the difficulty and practical significance of the MAIS task. + +To study the MAIS task, creating a multi-view AIS dataset is essential. However, annotating multi-view data based on existing or newly collected real-world data involve significant efforts and may not be accurate in identifying shapes of occluded regions. This is because manually annotated amodal masks in real-world datasets are often inaccurate and inconsistent due to the varying shape prior knowledge of annotators, as shown in Fig. 2 (copied from [40]). Therefore, using a synthetic approach would be more precise and controllable. To create a synthetic dataset, one option is to build upon existing synthetic AIS datasets [6, 13, 14]. However, these datasets lack high-quality 3D models and sufficient occlusion. To overcome the limitation, we propose to create a new synthetic dataset comprising reconstructed high-quality 3D models and sufficient occlusion by controlling the distribution of objects. As an initial step in exploring the MAIS task, we limit our dataset construction to a single scenario. Specifically, the shopping scenario is selected due to its potential for multiple camera arrangements and its tendency for severe occlusion when goods are piled up. Consequently, we introduce MUVA, a novel MUlti-View Amodal Instance Segmentation dataset. The dataset creation process follows a standard three-step approach. Initially, 3D artists construct models from images collected from on-sale items. Next, 3D models are then selected and placed in a 3D scene with careful compositions to control the occlusion degree. Finally, multi-view images are captured by six simulated cameras to simulate a real-world self-checkout setting. Each image is extensively annotated with visible/amodal segmentation masks, depth maps, occlusion orders, and 3D models. + +To our best knowledge, MUVA is the first and only multi-view AIS dataset currently available. Unlike real-world-based AIS datasets [19, 40, 8, 27], MUVA provides precise annotations in the occluded region due to its synthetic nature and known ground-truth 3D models. Besides, MUVA is also the largest image-level AIS dataset in terms + +of both images and instances. + +To exploit the multi-view information in MUVA, we introduce MASFormer, a novel method that aggregates information across different views and instances. Through comparative experiments with existing single-view-based AIS methods, we demonstrate that MASFormer significantly outperforms these methods by effectively utilizing multiview information. Additionally, our approach can accurately predict objects that are severely occluded from one angle by incorporating information from other angles. + +![](images/f214564f2001503276c7bc61ee05cceba21d2b41c1e1a2ed9a71b657a6733993.jpg) +Figure 2. Two examples of COCOA [40] dataset, displaying multiple annotated occluded regions by different annotators. + +Our contributions are summarized as follows: 1) A new task named MAIS is proposed to explore the AIS task under the multi-view setting for alleviating the ill-posed problem in the AIS task. 2) A novel dataset named MUVA is proposed for the MAIS task in the multi-view setting for shopping scenarios. To our best knowledge, MUVA is the first AIS dataset under the multi-view setting. 3) A new method named MASFormer is proposed to collect both view-level and instance-level information for solving the ill-posed problem in the AIS task. The experimental results show the efficiency of the multi-view setting over the single-view approach. + +# 2. Related Work + +# 2.1. Amodal Instance Segmentation Datasets + +Various single-view-based AIS datasets have been proposed, including the image and video levels. (1) For the image level, most of the datasets are re-annotated manually based on the existing datasets for the visible instance segmentation (VIS) [5, 17, 30] task. For example, COCOA [40, 8], BSDSA [40], KINS [27] and D2SA [8] are extended based on the VIS datasets, including COCO [23], BSDS [25], KITTI [9] and D2S [7]. However, human annotation of occluded regions in image-level datasets may lack accuracy and consistency due to variations in the annotator's perception of amodal shape. Besides, DYCE [6] is a synthetic dataset for indoor furniture. (2) For the video level, two synthetic datasets, SAIL-VOS [13] and SAIL-VOS 3D [14] have been generated based on the GTA 3D game, containing daily-life scenes. Compared to video-level datasets with temporal consistency, MUVA exhibits higher shape variability across different viewpoints. + +![](images/c882e580aa6a8a90188a6f72306a6f0204727a1990f5d27f963e9f87a4db1aec.jpg) +Figure 3. The pipeline of dataset generation. (a) For each object, 2D images are captured from up, down, left, right, front, and back, respectively. Then 3D artists use the collected images to reconstruct the 3D models. (b) For each scene, 3D models are randomly selected and placed with different amounts and orientations. (c) For each scene, six views are used to capture the data, including the RGB images and various annotations. + +# 2.2. Amodal Instance Segmentation Methods + +AIS methods employ various cues for amodal completion and can be categorized into three types based on relevant literature. First, numerous methods are adapted from VIS methods. Li and Malik [19] use Iterative Instance Segmentation [18] to solve the amodal problem. ORCNN [8] extends Mask-RCNN for simultaneous visible and amodal segmentations. ASN [27] learns features with a proposed multi-level aggregation module. OAFformer [20] proposes to learn the occlusion discriminative queries with a transformer-base network. Second, some studies utilize the relative occlusion order between objects, including SLN [38] predicts and combines the relative orders, and Deocclusion [35] employs a self-training method to learn an ordering map for guiding the amodal completion. Third, some studies use the shape prior knowledge to help infer the shape of the occluded region, such as Amodal-VAE [24], ShapeDict [33], GIN [22] and A3D [21]. However, the multi-view information is not utilized in existing methods due to the absence of a suitable dataset. Based on the proposed MUVA dataset, this paper presents a 2D approach to leverage multi-view knowledge. Instead of using sophisticated 3D approaches like reconstruction, our 2D approach can be easily applicable to real-world scenarios without requiring 3D supervision signals. + +# 3. MUVA: Multi-view Amodal Dataset + +MUVA comprises 1,801 distinct 3D objects reconstructed from multi-view photos. These objects are utilized to fabricate 4,401 scenes with diverse object placements. 26,406 RGB images are then produced from six cameras, each from differing viewpoints. The dataset includes thorough annotations, such as depth maps, 3D mod + +els, and amodal/visible masks. The dataset split of MUVA, including train, validation and test, are shown in the supplementary material. + +# 3.1. Dataset Contents + +The contents of MUVA including images and corresponding annotations are introduced below. RGB images are captured from each camera view with a resolution of $1920 \times 1080$ . The high-quality 3D reconstructed models lead to final rendered RGB images with rich scene details and high visual quality. Six types of annotations are available for each RGB image. (1) The segmentation annotations of instances contain both visible and amodal instance masks. These are generated by the 3D simulation software, resulting in higher accuracy compared to manual annotations. Moreover, the occluded region mask annotations are more precise compared to human-annotated amodal masks which may vary between annotators. (2) Depth maps are produced to reflect the value of each pixel with regard to its distance from the relevant camera to the 3D object. The depth map registers distance for visible regions exclusively, excluding amodal regions. (3) The occlusion order specifies the list of other objects occluded by this one. (4) Accompanying high-quality 3D models are included. (5) The bounding boxes and area of both visible and amodal masks derived from corresponding masks are provided. + +# 3.2. Dataset Generation + +A universal pipeline is designed to generate the synthetic dataset MUVA in three stages: building 3D models, placing 3D models, and capturing data, as illustrated in Fig. 3. + +3D Model Building. In this stage, 3D models are created as the foundation for the 3D scene, as presented in Fig. 3 (a). This stage contains two steps: (1) capturing six differ + +![](images/c88e1e52f8c996ef9612c1bdc613fda68e067c6956f483df054a648f62858de0.jpg) +Figure 4. The histogram of the number of instances for four parent categories (bags, others, bottles, boxes) and corresponding subcategories. Non-rigid categories are noted with star stripes. Best viewed in color. + +
DatasetPublicationData TypeMultiple Views# Image# InstanceScenarioSynthetic or Real3D ModelDepth# CategoriesResolution (pixels)
SAIL-VOS [13]CVPR'19video-111,6541,896,295daily lifesynthetic-✓1621M
SAIL-VOS 3D [14]CVPR'21video-237,6113,460,213daily lifesynthetic✓✓1781M
COCOA [40]CVPR'17image-5,00046,314daily lifereal--N/A0.28M
BSDSA [40]CVPR'17image-5003,739daily lifereal--N/A0.15M
DYCE [6]CVPR'18image-5,50085,975daily lifesynthetic--791M
KINS [27]CVPR'19image-14,991190,626streetreal--80.47M
D2SA [8]WACV'19image-5,60028,720shoppingreal--603M
COCOA-cls [8]WACV'19image-3,50110,562daily lifereal--800.28M
MUVAN/Aimage✓26,406198,573shoppingsynthetic✓✓202M
+ +Table 1. Comparison with existing amodal instance segmentation datasets. # means the number of this item. Bold numbers denote the largest one in each column among image-level datasets. + +ent images of each object to provide adequate information for 3D reconstruction, and (2) utilizing MAYA, a 3D modeling software, to reconstruct and manually refine the 3D objects iteratively by 3D artists. This process results in the reconstruction of 1801 distinct 3D objects, each with reconstructed shape and texture. + +3D Model Placing. This stage involves generating 3D scenes by selecting and placing 3D object models. It comprises two steps: 3D model selection and placement, as depicted in Fig. 3 (b). First, a shelf is created as a platform for scene construction, and 3D models are randomly chosen from those reconstructed in the previous stage. Second, placement settings, including object number, orientation, and position, are varied randomly to enhance diversity. The number of objects can range from less than 10 to more than 10, and their upright or flat placement is randomized. Object positions are also randomized, ensuring they are within the shelf's range. Finally, Unity3D software is used to render the scene. The physical simulation utilizes non-deformable 3D models with collision detection to prevent object penetration. The scenes were illuminated uniformly and gravity was applied to mimic realistic conditions. Creating all 1801 3D models required approximately + +600 hours with a 20-minute time frame for each model. The cost of generating the models totaled approximately 15,000 USD at a rate of 25 USD per hour for each 3D artist. + +Data Capture. The simulated scene depicted in Fig. 3 (c) provides various types of data for sampling. Six cameras are positioned in the front to capture sparse views and simulate the self-checkout setting, ensuring the applicability of MUVA to real-life scenarios. For each view, RGB images and numerous annotations are generated. + +The above dataset generation pipeline is adaptable for creating datasets for other vision tasks, such as indoor 3D reconstruction [4] and person re-identification [31]. + +# 3.3. Dataset Statistics + +MUVA dataset comprises 26,406 images with 198,573 instances categorized into four parent categories (bags, bottles, boxes, and others), and 20 sub-categories that include both rigid and non-rigid objects. The instance ratio of each category is presented in Fig. 4. The dataset contains $27.41\%$ non-rigid objects, such as the "Plastic Bag," which provides shape variations. The proposed dataset includes high-resolution images of $1920 \times 1080$ pixels, providing rich details of the objects' edges and surfaces. + +![](images/59ecc73200a81a1ca44d48210edc61a7caa5cce1a99ca61c57597a2d3b22de22.jpg) +Figure 5. Overall architecture of our method. There are two stages in our method, including the Feature Extraction Stage and the Multi-view Aggregation Stage. The first stage aims to extract the features of each instance from all views. The second stage utilizes the relationship of features at the instance level and view level, respectively, to generate accurate predictions. + +# 3.4. Comparison with Existing Datasets + +Tab. 1 presents a comparison between MUVA and other AIS datasets, including video and image-level datasets such as COCOA [40], BSDSA [40], DYCE [6], KINS [27], D2SA [8] and COCOA-cls [8]. MUVA stands out as the only dataset specifically designed for the multi-view AIS task and the only synthetic image-level dataset that provides 3D models. The 3D models used to build the dataset are publicly available to support new methods for the AIS task. Additionally, MUVA and D2SA are the only two datasets for the shopping scenario. MUVA's synthetic nature leads to consistent and higher-quality annotations than human-annotated datasets. Moreover, MUVA has the largest number of images and instances among image-level datasets, and is the only dataset at the image level that contains depth maps, which can potentially help with the AIS task. + +
Datasetsimplicity ↓convexity ↓
visibleamodalvisibleamodal
BSDS-A0.7180.8340.6160.643
COCO-A0.7460.8560.6580.685
KINS0.7090.8300.6100.639
MUVA0.9590.8010.9230.963
+ +Table 2. Complexity is evaluated through simplicity and convexity metrics. Small values of these metrics indicate a complex dataset. A circle shape yields the maximum value of 1.0 for both metrics. + +Shape Complexity. To assess the shape complexity of mask annotations contained in MUVA, metrics proposed by COCOA [40] is used. These metrics include convexity and simplicity for both visible and amodal masks. As shown in Tab. 2, MUVA has the lowest shape simplicity (0.801) and the highest convexity (0.963) of amodal masks. The high convexity can be attributed to the presence of goods such + +as bags, bottles, and boxes, which possess naturally convex shapes. Conversely, the low simplicity confirms that the shapes within MUVA are complex. For instance, a plastic bag with zigzagged boundaries exhibits high convexity but low simplicity. + +# 3.5. Applications + +MUVA provides diverse annotations that can be used for multiple research tasks. For example, using instance IDs from different viewpoints can lead to a new task of multi-view amodal instance segmentation (MAIS), which involves matching and segmenting the same instance from multiple viewpoints. High-quality 3D models can be used for single/multiple-view 3D reconstruction. The provided relative depth order annotation allows for occlusion order prediction. Finally, the depth map from the object to the camera can be utilized for depth estimation. + +# 4. Method + +This paper focuses on the newly formulated multi-view amodal instance segmentation (MAIS) task. This section proposes a network designed for the MAIS task, named Multi-view Amodal Segmentation Transformer (MAS-Former). The task definition, overall architecture, and the proposed new modules are introduced in the following. + +# 4.1. Overview + +Problem Definition. Given $N$ input images from $N$ viewpoints, the MAIS task aims to predict $K$ instance-level segmentation masks for interested objects in each image. + +Overall Architecture. The whole pipeline of the proposed method contains two stages, including the Feature Extraction Stage (FES) and the Multi-view Aggregation Stage (MAS). (1) The FES extracts features of each instance + +from all angles. (2) The MAS takes the instances' feature from FES as input and optimizes from two aspects, including aggregating all instances' features of the same view and all views' features of the same instance. Finally, the amodal instance predictions of objects in all images are generated after fusion. + +# 4.2. Feature Extraction Stage + +This stage aims to extract features from all views simultaneously. As shown in Fig. 5, the Backbone takes for $N$ images as input and extracts representative features for $K$ instances, including low-level structural details and high-level semantic information. Next, the CNN Decoder up-samples the representative features and generates multilevel features containing all objects' information. Then a Transformer Decoder is employed to output features $F_{FES}$ corresponding to all objects in all views. Bipartite matching [2] is used to find the correspondence between predictions and supervisions, to specify the view id and instance id of each feature. + +# 4.3. Multi-view Aggregation Stage + +As shown in Fig. 5, this stage aims to enhance the extracted features $F_{FES}$ from two aspects, including view-level and instance-level. Two branches are designed for the two aspects, respectively. + +View-level Aggregation. This branch aims to utilize the relationship between features of all instances in the same view for enhancing each instance's feature quality. Firstly, for input features $F_{FES}$ including all objects in all views, an View Feature Grouping module takes features of the same view into the same group. Then the View-level Attention module learns the correlation between all instances' features in the same view. Finally, the feature of each instance is enhanced by integrating all correlated instances' features in the same view. Here the correlation between different features is computed by cosine similarity. And the self-attention [32] is used to construct this module. Please refer to our supplementary material for detailed explanations of the network. Besides, this module requires objects in different views could be identified and matched. To achieve this, for each instance, both the view id and the instance id are predicted by the network and supervised by using the bipartite matching [2] to match between the prediction and ground truth. + +Instance-level Aggregation. This module aims to use features of the same instance in all views to improve the feature quality of each instance. First, the Instance Feature Grouping module takes features of the same instance across all views to the same group. Next, for each group, the Instance-level Attention module learns correlations between features of the same instance in different views and integrates associated features by using the self-attention [32] + +mechanism. + +Finally, a CNN-based fuse layer is used to merge the output features of two branches for the final prediction of amodal masks. With the aggregation of two branches, the feature representations of all instances can be enhanced, and more precise amodal segmentation results can be obtained. + +# 5. Experiments + +This section first compares the newly proposed method MASFormer with existing single-view-based state-of-the-art AIS methods on the proposed MUVA dataset. Then the ablation studies are conducted to show the effectiveness of amount and order for the input viewpoints and components of the proposed method. + +
MethodPublicationAPAP50AP75AR
Mask-RCNN [11]ICCV'1717.226.618.748.8
ORCNN [8]WACV'197.825.92.124.7
SLN [38]ACM MM'196.920.25.622.9
DeepSnake [26]CVPR'207.711.97.423.8
BCNet [16]CVPR'2123.128.925.040.9
ShapeDict [33]AAAI'219.936.01.327.8
E2EC [37]CVPR'2211.815.712.925.5
Baseline (1 view)CVPR'2217.826.118.029.2
Baseline (6 views)CVPR'2222.935.522.336.4
Ours (1 view)N/A25.638.025.641.2
Ours (6 views)N/A39.455.940.351.8
+ +Table 3. Compared with state-of-the-art methods on MUVA. In each column, the best is in bold, and the second-best is underlined. + +
MethodResNet-50ResNet-101ResNeXt-101
MaskRCNN17.219.119.8
BCNet23.125.326.6
E2EC11.814.215.9
Ours (6 views)39.442.543.0
+ +Table 4. Performance of methods with stronger backbones. + +Experimental Settings. The baseline method only contains the first stage FES in the proposed method MAS-Former, which is implemented following the video instance segmentation method Mask2Former [3] as an instantiation. The baseline method can take multi-view images as input and outputs amodal segmentation masks, the same as MAS-Former. ResNet-FPN-50 [12] is employed as the backbone for all methods. The results are evaluated using the AP and AR metric, commonly used to measure the precision and recall of prediction. For fairness, all experiments use the same training dataset of MUVA to train and the same validation dataset of MUVA to validate. The ground truth of all methods is the same, including the bounding boxes and masks for amodal and visible regions, image ids, and instance ids. The ground-truth camera viewpoint information and 3D models are not used for fairness. + +![](images/2158de3ad8dcc0542226875e4647873673e85313d756928b263050f6feef2b25.jpg) +Figure 6. Visualization comparisons between BCNet [16] and ours on MUVA, trained with one viewpoint (1V) and six viewpoints (6V). For masks, different colors denote different instances, and the same instance in different angles has the same color. Red circles indicate regions should be focused. Zoom in for a better view. In the first and third columns, even if a bottle is severely occluded, it can be predicted accurately by our method. Moreover, our method trained with 6 views performs better than training with a single view. + +# 5.1. Multi-view Amodal Instance Segmentation + +Tab. 3 shows the comparison results of some existing AIS methods on MUVA. Several state-of-the-art methods designed for single-view datasets are compared. For baseline and the proposed method MASFormer, two kinds of input are used during training, one is a single view, and the other is six. Note that the amount of training data is the same for these two settings. + +We compare the results at three levels, including one-view, one vs. six views, and six-view levels. (1) As shown in Tab. 3, when only using one view for training, our proposed method MASFormer achieves the best performance $(25.6\% AP, 38.0\% AP_{50}, 25.6\% AP_{75}, 41.2\% AR)$ on all metrics. MASFormer outperforms the best performance of single-view-based methods with $2.7\% AP, 2.0\% AP_{50}, 0.6\% AP_{75}$ , and $0.2\% AR$ . The results demonstrate the effectiveness of the proposed view-level attention module, which can learn the relationship between different instances of the same view and improve the amodal prediction with the help of a learned relationship. (2) Both ours and the baseline method achieve better performance when using six views than one view for training. The results show that even with the same training data, using more views as input for training can improve the prediction. (3) When both methods use six views for training, our method can outperform the baseline method with $16.5\%$ AP. The results show the effectiveness of the proposed instance-level attention module, which learns and benefits from the relationship between different views of the same instance. Besides, the performance of methods with stronger backbones is shown in Tab. 4. Stronger backbones bring improvements for all + +methods, while the proposed MASFormer still achieves the best performance. Qualitative results are shown in Fig. 6. + +
SettingTraining DatasetTesting DatasetAP
1D2SAtrainD2SAval63.5
2MUVAtrainD2SAval41.9
3D2SAtrain + MUVAtrainD2SAval68.4
+ +Table 5. Performance of MASFormer evaluated on the validation set of D2SA dataset and trained with different combinations of source-domain datasets for training. For the two datasets, only data of overlapped categories are used. + +# 5.2. Generalization to Real-world Scenarios + +In this section, we demonstrate the generalization ability of the proposed dataset and method on real-world scenarios under single-view and multi-view settings, respectively. + +Single-view Generalization. To validate generalization ability in real-world scenarios, the MUVA dataset is utilized under a single-view setting. To be specific, we employ settings of the domain generalization [39, 10, 15] task to evaluate the generalization ability of learning from a source domain, typically synthetic datasets, to out-of-distribution target domains like real-world datasets. Specifically, the MUVA synthetic dataset and real-world AIS dataset D2SA [8] are used in this study. D2SA contains 60 categories, of which 18 categories overlap with MUVA. More information about the category labels can be found in the supplementary material. The following experiments only consider data from the overlapping categories. Three settings were adopted as presented in Tab. 5. Firstly, MASFormer is trained and evaluated on the train and validation sets of + +D2SA datasets, demonstrating its ability to generalize well on real-world data. Secondly, MASFormer is trained on the synthetic MUVA dataset and evaluated on the real-world dataset D2SA, with results validating the generalizability of the synthetic MUVA dataset. Lastly, mixing D2SA and MUVA for training lead to a $4.9\%$ AP improvement, indicating the benefits of using MUVA in a real-world scenario. + +![](images/e726f945697326db7618159e11eb156c1abeeae538bdbad3711cdcfd37f2a0a1.jpg) +Figure 7. Qualitative results of a real-world case. Red circles indicate differences between ours and BCNet. Zoom in for a better view. + +Multi-view Generalization. Considering there is no existing multi-view real-world AIS dataset, we construct a real-world shopping scenario to obtain multi-view data for validating the generalization ability of the proposed dataset and method. Images are captured from the left, middle, and right sides, respectively. MASFormer trained with six views and BCNet are used. And the train set of MUVA is utilized for training. As shown in Fig. 7, MASFormer can obtain good amodal segmentation results, demonstrating the generalization ability of MUVA to real-world scenarios. Moreover, when compared with BCNet, MASFormer performs better consistently on all viewpoints, validating its potential for generalizing to the real-world scene. + +
Views Order# ViewsAPAP50AP75AR
N/A125.638.025.639.2
Fixed Order226.238.026.339.8
328.042.927.740.9
430.945.630.943.5
534.149.034.747.4
637.953.938.651.4
Random Order226.939.527.140.4
328.441.728.442.9
432.846.633.445.6
536.952.737.250.5
639.455.940.351.8
+ +# 5.3. Ablation Study + +We conducted ablation study experiments for MAS-Former, examining the impact of the number and order of + +input viewpoints, the effectiveness of attention modules, and computational cost. + +Viewpoints Count and Order. Tab 6 presents some combinations of the number and order of input viewpoints used for training in the proposed MASFormer method. The same amount of training data is used for all experiments. Performance consistently improves as the number of input views increases, regardless of whether their order is fixed (rows # 2 to # 6) or random (rows # 7 to # 11). These results show that using more views for training can improve performance and multi-view data is crucial for amodal instance segmentation. When the number of input views is constant, the impact of the input views' order is analyzed below. As shown in Tab. 6, results of random input order outperform fixed order ones with the equal number of input views. For example, random order improves the $AP$ metric with the following percentages compared to fixed order: $0.7\%$ (2 views), $0.4\%$ (3 views), $1.9\%$ (4 views), $2.8\%$ (5 views) and $1.5\%$ (6 views). Results show that randomizing input image ordering of various viewpoints leads to increased training sample distribution and improved effectiveness. + +Table 6. Effect of fixing views input order and views amount. In each column, the best is in bold, and the second-best is underlined. + +
IndexView-levelInstance-levelAPAP50AP75AR
122.935.522.336.4
2✓28.743.128.341.6
3✓34.149.034.747.4
4✓✓39.455.940.351.8
+ +Attention Modules. Tab. 7 shows the ablation study of proposed attention modules proposed in our MASFormer method, using six input views with random order. The proposed view-level attention module improves $AP$ performance from $22.9\%$ to $28.7\%$ by learning feature relationships within the same view. Instance-level attention module achieves an $11.2\%$ improvement by utilizing multi-view features of the same instance. Both attention modules combined result in a $39.4\%$ $AP$ performance, surpassing individual settings. + +Table 7. Effect of two attention modules in the proposed method. + +
MethodFrameworkGPU MemFPSTimeAP
BCNetCNN4G8.34h23.1
BaselineTransformer9G6.56h22.9
OursTransformer13G3.78h39.4
+ +Table 8. Comparison of computational cost and the performance. Time means the training time. + +# 5.4. Computational Cost + +Tab. 8 compares the computational cost. The ResNet50-FPN backbone is used for all methods. The FPS is the average of all images in the validation dataset. Compared to other methods, our method exhibits superior performance at + +the expense of higher computational cost due to the use of Transformer framework. + +# 6. Limitation and Conclusion + +Limitations of this paper include the consideration of only one scenario, shopping, and a high computational cost of the proposed method. Future research should aim to expand the dataset to include other scenarios and develop a more efficient network that incorporates additional information such as 3D models from MUVA. As for the conclusion, this paper introduces a novel task called multi-view amodal instance segmentation (MAIS) in the shopping scenario. To facilitate research in this area, a new synthetic dataset, MUVA, is introduced along with a proposed method that utilizes multi-view information. + +# Acknowledgments + +This work was partially supported by the Natural Science Foundation of China under contract 62088102. This work was also partially supported by Qualcomm. We also acknowledge High-Performance Computing Platform of Peking University for providing computational resources. + +# References + +[1] Seunghyeok Back, Joosoon Lee, Taewon Kim, Sangjun Noh, Raeyoung Kang, Seongho Bak, and Kyoobin Lee. Unseen object amodal instance segmentation via hierarchical occlusion modeling. In International Conference on Robotics and Automation, pages 5085-5092, 2022. +[2] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 213-229, 2020. +[3] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1290–1299, 2022. +[4] Angela Dai, Angel X Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. ScanNet: Richly-annotated 3D reconstructions of indoor scenes. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5828-5839, 2017. +[5] Kaiwen Duan, Song Bai, Lingxi Xie, Honggang Qi, Qingming Huang, and Qi Tian. CenterNet: Keypoint triplets for object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6569-6578, 2019. +[6] Kiana Ehsani, Roozbeh Mottaghi, and Ali Farhadi. SeGAN: Segmenting and generating the invisible. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6144-6153, 2018. + +[7] Patrick Follmann, Tobias Bottger, Philipp Hartinger, Rebecca Konig, and Markus Ulrich. MVtec D2S: Densely segmented supermarket dataset. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 569-585, 2018. +[8] Patrick Follmann, Rebecca König, Philipp Hartinger, Michael Klostermann, and Tobias Böttger. Learning to see the invisible: End-to-end trainable amodal instance segmentation. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1328-1336, 2019. +[9] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the KITTI vision benchmark suite. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3354-3361, 2012. +[10] Ishaan Gulrajani and David Lopez-Paz. In search of lost domain generalization. In International Conference on Learning Representations, 2021. +[11] Kaiming He, Georgia Gkioxari, Piotr Dólar, and Ross Girshick. Mask R-CNN. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2961-2969, 2017. +[12] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016. +[13] Yuan-Ting Hu, Hong-Shuo Chen, Kexin Hui, Jia-Bin Huang, and Alexander G Schwing. SAIL-VOS: Semantic amodal instance level video object segmentation - a synthetic dataset and baselines. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3105-3115, 2019. +[14] Yuan-Ting Hu, Jiahong Wang, Raymond A. Yeh, and Alexander G. Schwing. SAIL-VOS 3D: A synthetic dataset and baselines for object detection and 3D mesh reconstruction from video data. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops, pages 3359-3369, 2021. +[15] Xueying Jiang, Jiaxing Huang, Sheng Jin, and Shijian Lu. Domain generalization via balancing training difficulty and model capability. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2023. +[16] Lei Ke, Yu-Wing Tai, and Chi-Keung Tang. Deep occlusion-aware instance segmentation with overlapping bilayers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4019–4028, 2021. +[17] Youngwan Lee and Jongyoul Park. CenterMask: Realtime anchor-free instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13906-13915, 2020. +[18] Ke Li, Bharath Hariharan, and Jitendra Malik. Iterative instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3659-3667, 2016. +[19] Ke Li and Jitendra Malik. Amodal instance segmentation. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 677-693, 2016. + +[20] Zhixuan Li, Ruohua Shi, Tiejun Huang, and Tingting Jiang. OAFormer: Learning occlusion distinguishable feature for amodal instance segmentation. In International Conference on Acoustics, Speech, and Signal Processing, pages 1-5, 2023. +[21] Zhixuan Li, Weining Ye, Tingting Jiang, and Tiejun Huang. 2D amodal instance segmentation guided by 3D shape prior. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 165-181, 2022. +[22] Zhixuan Li, Weining Ye, Tingting Jiang, and Tiejun Huang. GIN: Generative invariant shape prior for amodal instance segmentation. In IEEE Transactions on Multimedia, 2023. +[23] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dálár, and C Lawrence Zitnick. Microsoft COCO: Common objects in context. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 740-755, 2014. +[24] Huan Ling, David Acuna, Karsten Kreis, Seung Wook Kim, and Sanja Fidler. Variational amodal object completion. In Advances in Neural Information Processing Systems, pages 16246-16257, 2020. +[25] D. Martin, C. Fowlkes, D. Tal, and J. Malik. A database of human segmented natural images and its application to evaluating segmentation algorithms and measuring ecological statistics. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 416-423, 2001. +[26] Sida Peng, Wen Jiang, Huaijin Pi, Xiuli Li, Hujun Bao, and Xiaowei Zhou. Deep snake for real-time instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. +[27] Lu Qi, Li Jiang, Shu Liu, Xiaoyong Shen, and Jiaya Jia. Amodal instance segmentation with KINS dataset. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3014-3023, 2019. +[28] Mennatullah Siam, Sara Elkerdawy, Martin Jagersand, and Senthil Yogamani. Deep semantic segmentation for automated driving: Taxonomy, roadmap and challenges. In IEEE International Conference on Intelligent Transportation Systems, pages 1-8, 2017. +[29] Xiaolin Song, Kaili Zhao, Wen-Sheng Chu, Honggang Zhang, and Jun Guo. Progressive refinement network for occluded pedestrian detection. In Proceedings of the IEEE/CVF European Conference on Computer Vision, 2020. +[30] Zhi Tian, Chunhua Shen, and Hao Chen. Conditional convolutions for instance segmentation. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 282-298, 2020. +[31] Gül Varol, Javier Romero, Xavier Martin, Naureen Mahmood, Michael Black, Ivan Laptev, and Cordelia Schmid. Learning from synthetic humans. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4627-4635, 2017. +[32] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Advances in Neural Information Processing Systems, pages 5998-6008, 2017. + +[33] Yuting Xiao, Yanyu Xu, Ziming Zhong, Weixin Luo, Jiawei Li, and Shenghua Gao. Amodal segmentation based on visible region segmentation and shape prior. In Proceedings of the AAAI Conference on Artificial Intelligence, pages 2995-3003, 2021. +[34] Jin Xie, Yanwei Pang, M. H. Khan, Rao Muhammad Anwer, Fahad Shahbaz Khan, and Ling Shao. Mask-guided attention network and occlusion-sensitive hard example mining for occluded pedestrian detection. IEEE Transactions on Image Processing, 30:3872-3884, 2021. +[35] Xiaohang Zhan, Xingang Pan, Bo Dai, Ziwei Liu, Dahua Lin, and Chen Change Loy. Self-supervised scene de- occlusion. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3784- 3792, 2020. +[36] Shifeng Zhang, Longyin Wen, Xiao Bian, Zhen Lei, and S. Li. Occlusion-aware R-CNN: Detecting pedestrians in a crowd. In Proceedings of the IEEE/CVF European Conference on Computer Vision, 2018. +[37] Tao Zhang, Shiqing Wei, and Shunping Ji. E2EC: An end-to-end contour-based method for high-quality high-speed instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4443-4452, 2022. +[38] Ziheng Zhang, Anpei Chen, Ling Xie, Jingyi Yu, and Shenghua Gao. Learning semantics-aware distance map with semantics layering network for amodal instance segmentation. In Proceedings of the ACM International Conference on Multimedia, pages 2124-2132, 2019. +[39] Kaiyang Zhou, Yongxin Yang, Yu Qiao, and Tao Xiang. Domain generalization with mixstyle. In International Conference on Learning Representations, 2021. +[40] Yan Zhu, Yuandong Tian, Dimitris Metaxas, and Piotr Dólar. Semantic amodal segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1464-1472, 2017. \ No newline at end of file diff --git a/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/images.zip b/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..1d0ad8d00af49e6b4aea6867fea8da6511c6f8b5 --- /dev/null +++ b/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:548f6b7b064960938ab6b330bb5f938e5079f911ee63fff0cf1d6140f91c8d3d +size 700734 diff --git a/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/layout.json b/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..a36b4237b7f96d50361157117931f5ceb856fad8 --- /dev/null +++ b/2023/MUVA_ A New Large-Scale Benchmark for Multi-View Amodal Instance Segmentation in the Shopping Scenario/layout.json @@ -0,0 +1,6571 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 73, + 102, + 521, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 73, + 102, + 521, + 140 + ], + "spans": [ + { + "bbox": [ + 73, + 102, + 521, + 140 + ], + "type": "text", + "content": "MUVA: A New Large-Scale Benchmark for Multi-view Amodal Instance Segmentation in the Shopping Scenario" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "spans": [ + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "text", + "content": "Zhixuan Li" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "text", + "content": " Weining Ye" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "text", + "content": " Juan Terven" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "text", + "content": " Zachary Bennett" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "text", + "content": " Ying Zheng" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "text", + "content": " Tingting Jiang" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "inline_equation", + "content": "^{1,*}" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "text", + "content": " Tiejun Huang" + }, + { + "bbox": [ + 138, + 160, + 453, + 190 + ], + "type": "inline_equation", + "content": "^{1,3}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 78, + 191, + 515, + 217 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 78, + 191, + 515, + 217 + ], + "spans": [ + { + "bbox": [ + 78, + 191, + 515, + 217 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 78, + 191, + 515, + 217 + ], + "type": "text", + "content": " National Engineering Research Center of Visual Technology, National Key Laboratory for Multimedia Information Processing, School of Computer Science, Peking University, Beijing 100871, China" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 208, + 218, + 386, + 230 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 208, + 218, + 386, + 230 + ], + "spans": [ + { + "bbox": [ + 208, + 218, + 386, + 230 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 208, + 218, + 386, + 230 + ], + "type": "text", + "content": " AiFi Inc., California 94010, United States" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 138, + 232, + 456, + 274 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 138, + 232, + 456, + 274 + ], + "spans": [ + { + "bbox": [ + 138, + 232, + 456, + 274 + ], + "type": "text", + "content": "3 Beijing Academy of Artificial Intelligence, Beijing 100084, China {zhixuanli,ywning}@pku.edu.cn, {juan,zachary}@aifi.com, yingz@alumni.gsb.stanford.edu, {ttjiang,tjhuang}@pku.edu.cn" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 143, + 300, + 192, + 313 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 300, + 192, + 313 + ], + "spans": [ + { + "bbox": [ + 143, + 300, + 192, + 313 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 326, + 290, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 326, + 290, + 590 + ], + "spans": [ + { + "bbox": [ + 46, + 326, + 290, + 590 + ], + "type": "text", + "content": "Amodal Instance Segmentation (AIS) endeavors to accurately deduce complete object shapes that are partially or fully occluded. However, the inherent ill-posed nature of single-view datasets poses challenges in determining occluded shapes. A multi-view framework may help alleviate this problem, as humans often adjust their perspective when encountering occluded objects. At present, this approach has not yet been explored by existing methods and datasets. To bridge this gap, we propose a new task called Multi-view Amodal Instance Segmentation (MAIS) and introduce the MUVA dataset, the first MUlti-View AIS dataset that takes the shopping scenario as instantiation. MUVA provides comprehensive annotations, including multi-view amodal/visible segmentation masks, 3D models, and depth maps, making it the largest image-level AIS dataset in terms of both the number of images and instances. Additionally, we propose a new method for aggregating representative features across different instances and views, which demonstrates promising results in accurately predicting occluded objects from one viewpoint by leveraging information from other viewpoints. Besides, we also demonstrate that MUVA can benefit the AIS task in real-world scenarios." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 609, + 128, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 609, + 128, + 623 + ], + "spans": [ + { + "bbox": [ + 47, + 609, + 128, + 623 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 630, + 287, + 678 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 630, + 287, + 678 + ], + "spans": [ + { + "bbox": [ + 46, + 630, + 287, + 678 + ], + "type": "text", + "content": "The amodal instance segmentation (AIS) task aims to determine an object's entire shape, encompassing its visible and occluded components. AIS task is more challenging than the visible instance segmentation task [23, 11]" + } + ] + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 321, + 300, + 532, + 485 + ], + "blocks": [ + { + "bbox": [ + 321, + 300, + 532, + 485 + ], + "lines": [ + { + "bbox": [ + 321, + 300, + 532, + 485 + ], + "spans": [ + { + "bbox": [ + 321, + 300, + 532, + 485 + ], + "type": "image", + "image_path": "9b2be6dd5e1bed2e89f851c89adf672e90b2bebd49153de9e77dcb2dcc34349d.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 493, + 547, + 550 + ], + "lines": [ + { + "bbox": [ + 304, + 493, + 547, + 550 + ], + "spans": [ + { + "bbox": [ + 304, + 493, + 547, + 550 + ], + "type": "text", + "content": "Figure 1. Comparison of the impact of ill-posed problems on amodal prediction in single-view and multi-view input settings. (a) In single-view input, ambiguity arises due to multiple candidates for the occluded object. (b) Multi-view input helps alleviate ambiguity and improves amodal prediction accuracy." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 558, + 547, + 632 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 547, + 632 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 547, + 632 + ], + "type": "text", + "content": "as it lacks occluded region appearance. Despite its complexity, the AIS task has significant implications for various industrial applications that encounter occlusion problems, such as robotic arm grasping [1], pedestrian re-identification [34, 36, 29], automatic driving [27, 28], and self-checkout systems in supermarkets [8]." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 641, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 547, + 715 + ], + "type": "text", + "content": "Although numerous datasets [19, 40, 8, 27, 13] and methods [19, 40, 8, 27, 13, 38, 33, 21] have been proposed since the AIS task was firstly introduced in 2016 by Li and Malik [19], current AIS datasets and methods rely on a single-view approach, suffering from the ill-posed problem. For example, as shown in Fig. 1(a), directly deducting" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 57, + 683, + 136, + 693 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 683, + 136, + 693 + ], + "spans": [ + { + "bbox": [ + 57, + 683, + 136, + 693 + ], + "type": "text", + "content": "*Corresponding author" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 47, + 693, + 287, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 693, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 693, + 287, + 713 + ], + "type": "text", + "content": "1The proposed MUVA dataset can be downloaded from this link: https://zhixuanli.github.io/project_2023_ICCVMUVA." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "23504" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 288, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 288, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 288, + 156 + ], + "type": "text", + "content": "the complete shape from a single-view image is extremely challenging due to the presence of occluded regions with multiple potential candidates. This is because distinct objects can share the same visible appearance but differ in shape within the occluded region. However, as shown in Fig. 1(b), humans tend to observe occluded objects from multiple angles to obtain accurate predictions." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 158, + 287, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 158, + 287, + 266 + ], + "spans": [ + { + "bbox": [ + 46, + 158, + 287, + 266 + ], + "type": "text", + "content": "Inspired by this observation, this paper proposes a novel task called MAIS (Multi-view Amodal Instance Segmentation), which predicts amodal segmentations through multiple viewpoints. The task is designed for real-world applications, under the assumption that the number of viewpoints and field of vision is limited, and objects in the scene are closely distributed with reasonable occlusion. These assumptions contribute to the difficulty and practical significance of the MAIS task." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 268, + 288, + 639 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 268, + 288, + 639 + ], + "spans": [ + { + "bbox": [ + 46, + 268, + 288, + 639 + ], + "type": "text", + "content": "To study the MAIS task, creating a multi-view AIS dataset is essential. However, annotating multi-view data based on existing or newly collected real-world data involve significant efforts and may not be accurate in identifying shapes of occluded regions. This is because manually annotated amodal masks in real-world datasets are often inaccurate and inconsistent due to the varying shape prior knowledge of annotators, as shown in Fig. 2 (copied from [40]). Therefore, using a synthetic approach would be more precise and controllable. To create a synthetic dataset, one option is to build upon existing synthetic AIS datasets [6, 13, 14]. However, these datasets lack high-quality 3D models and sufficient occlusion. To overcome the limitation, we propose to create a new synthetic dataset comprising reconstructed high-quality 3D models and sufficient occlusion by controlling the distribution of objects. As an initial step in exploring the MAIS task, we limit our dataset construction to a single scenario. Specifically, the shopping scenario is selected due to its potential for multiple camera arrangements and its tendency for severe occlusion when goods are piled up. Consequently, we introduce MUVA, a novel MUlti-View Amodal Instance Segmentation dataset. The dataset creation process follows a standard three-step approach. Initially, 3D artists construct models from images collected from on-sale items. Next, 3D models are then selected and placed in a 3D scene with careful compositions to control the occlusion degree. Finally, multi-view images are captured by six simulated cameras to simulate a real-world self-checkout setting. Each image is extensively annotated with visible/amodal segmentation masks, depth maps, occlusion orders, and 3D models." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 641, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 287, + 714 + ], + "type": "text", + "content": "To our best knowledge, MUVA is the first and only multi-view AIS dataset currently available. Unlike real-world-based AIS datasets [19, 40, 8, 27], MUVA provides precise annotations in the occluded region due to its synthetic nature and known ground-truth 3D models. Besides, MUVA is also the largest image-level AIS dataset in terms" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 305, + 72, + 426, + 84 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 426, + 84 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 426, + 84 + ], + "type": "text", + "content": "of both images and instances." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 87, + 545, + 196 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 87, + 545, + 196 + ], + "spans": [ + { + "bbox": [ + 304, + 87, + 545, + 196 + ], + "type": "text", + "content": "To exploit the multi-view information in MUVA, we introduce MASFormer, a novel method that aggregates information across different views and instances. Through comparative experiments with existing single-view-based AIS methods, we demonstrate that MASFormer significantly outperforms these methods by effectively utilizing multiview information. Additionally, our approach can accurately predict objects that are severely occluded from one angle by incorporating information from other angles." + } + ] + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 321, + 211, + 531, + 255 + ], + "blocks": [ + { + "bbox": [ + 321, + 211, + 531, + 255 + ], + "lines": [ + { + "bbox": [ + 321, + 211, + 531, + 255 + ], + "spans": [ + { + "bbox": [ + 321, + 211, + 531, + 255 + ], + "type": "image", + "image_path": "f214564f2001503276c7bc61ee05cceba21d2b41c1e1a2ed9a71b657a6733993.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 261, + 545, + 283 + ], + "lines": [ + { + "bbox": [ + 305, + 261, + 545, + 283 + ], + "spans": [ + { + "bbox": [ + 305, + 261, + 545, + 283 + ], + "type": "text", + "content": "Figure 2. Two examples of COCOA [40] dataset, displaying multiple annotated occluded regions by different annotators." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 300, + 545, + 445 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 300, + 545, + 445 + ], + "spans": [ + { + "bbox": [ + 304, + 300, + 545, + 445 + ], + "type": "text", + "content": "Our contributions are summarized as follows: 1) A new task named MAIS is proposed to explore the AIS task under the multi-view setting for alleviating the ill-posed problem in the AIS task. 2) A novel dataset named MUVA is proposed for the MAIS task in the multi-view setting for shopping scenarios. To our best knowledge, MUVA is the first AIS dataset under the multi-view setting. 3) A new method named MASFormer is proposed to collect both view-level and instance-level information for solving the ill-posed problem in the AIS task. The experimental results show the efficiency of the multi-view setting over the single-view approach." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 465, + 392, + 478 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 465, + 392, + 478 + ], + "spans": [ + { + "bbox": [ + 306, + 465, + 392, + 478 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 488, + 517, + 501 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 488, + 517, + 501 + ], + "spans": [ + { + "bbox": [ + 306, + 488, + 517, + 501 + ], + "type": "text", + "content": "2.1. Amodal Instance Segmentation Datasets" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 510, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 510, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 545, + 713 + ], + "type": "text", + "content": "Various single-view-based AIS datasets have been proposed, including the image and video levels. (1) For the image level, most of the datasets are re-annotated manually based on the existing datasets for the visible instance segmentation (VIS) [5, 17, 30] task. For example, COCOA [40, 8], BSDSA [40], KINS [27] and D2SA [8] are extended based on the VIS datasets, including COCO [23], BSDS [25], KITTI [9] and D2S [7]. However, human annotation of occluded regions in image-level datasets may lack accuracy and consistency due to variations in the annotator's perception of amodal shape. Besides, DYCE [6] is a synthetic dataset for indoor furniture. (2) For the video level, two synthetic datasets, SAIL-VOS [13] and SAIL-VOS 3D [14] have been generated based on the GTA 3D game, containing daily-life scenes. Compared to video-level datasets with temporal consistency, MUVA exhibits higher shape variability across different viewpoints." + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23505" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 78, + 71, + 517, + 227 + ], + "blocks": [ + { + "bbox": [ + 78, + 71, + 517, + 227 + ], + "lines": [ + { + "bbox": [ + 78, + 71, + 517, + 227 + ], + "spans": [ + { + "bbox": [ + 78, + 71, + 517, + 227 + ], + "type": "image", + "image_path": "c882e580aa6a8a90188a6f72306a6f0204727a1990f5d27f963e9f87a4db1aec.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 235, + 547, + 278 + ], + "lines": [ + { + "bbox": [ + 46, + 235, + 547, + 278 + ], + "spans": [ + { + "bbox": [ + 46, + 235, + 547, + 278 + ], + "type": "text", + "content": "Figure 3. The pipeline of dataset generation. (a) For each object, 2D images are captured from up, down, left, right, front, and back, respectively. Then 3D artists use the collected images to reconstruct the 3D models. (b) For each scene, 3D models are randomly selected and placed with different amounts and orientations. (c) For each scene, six views are used to capture the data, including the RGB images and various annotations." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 297, + 260, + 308 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 297, + 260, + 308 + ], + "spans": [ + { + "bbox": [ + 47, + 297, + 260, + 308 + ], + "type": "text", + "content": "2.2. Amodal Instance Segmentation Methods" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 316, + 289, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 316, + 289, + 604 + ], + "spans": [ + { + "bbox": [ + 46, + 316, + 289, + 604 + ], + "type": "text", + "content": "AIS methods employ various cues for amodal completion and can be categorized into three types based on relevant literature. First, numerous methods are adapted from VIS methods. Li and Malik [19] use Iterative Instance Segmentation [18] to solve the amodal problem. ORCNN [8] extends Mask-RCNN for simultaneous visible and amodal segmentations. ASN [27] learns features with a proposed multi-level aggregation module. OAFformer [20] proposes to learn the occlusion discriminative queries with a transformer-base network. Second, some studies utilize the relative occlusion order between objects, including SLN [38] predicts and combines the relative orders, and Deocclusion [35] employs a self-training method to learn an ordering map for guiding the amodal completion. Third, some studies use the shape prior knowledge to help infer the shape of the occluded region, such as Amodal-VAE [24], ShapeDict [33], GIN [22] and A3D [21]. However, the multi-view information is not utilized in existing methods due to the absence of a suitable dataset. Based on the proposed MUVA dataset, this paper presents a 2D approach to leverage multi-view knowledge. Instead of using sophisticated 3D approaches like reconstruction, our 2D approach can be easily applicable to real-world scenarios without requiring 3D supervision signals." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 620, + 247, + 632 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 620, + 247, + 632 + ], + "spans": [ + { + "bbox": [ + 47, + 620, + 247, + 632 + ], + "type": "text", + "content": "3. MUVA: Multi-view Amodal Dataset" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 642, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 287, + 715 + ], + "type": "text", + "content": "MUVA comprises 1,801 distinct 3D objects reconstructed from multi-view photos. These objects are utilized to fabricate 4,401 scenes with diverse object placements. 26,406 RGB images are then produced from six cameras, each from differing viewpoints. The dataset includes thorough annotations, such as depth maps, 3D mod" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 297, + 545, + 333 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 297, + 545, + 333 + ], + "spans": [ + { + "bbox": [ + 305, + 297, + 545, + 333 + ], + "type": "text", + "content": "els, and amodal/visible masks. The dataset split of MUVA, including train, validation and test, are shown in the supplementary material." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 342, + 409, + 354 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 342, + 409, + 354 + ], + "spans": [ + { + "bbox": [ + 306, + 342, + 409, + 354 + ], + "type": "text", + "content": "3.1. Dataset Contents" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 361, + 545, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 361, + 545, + 613 + ], + "spans": [ + { + "bbox": [ + 304, + 361, + 545, + 613 + ], + "type": "text", + "content": "The contents of MUVA including images and corresponding annotations are introduced below. RGB images are captured from each camera view with a resolution of " + }, + { + "bbox": [ + 304, + 361, + 545, + 613 + ], + "type": "inline_equation", + "content": "1920 \\times 1080" + }, + { + "bbox": [ + 304, + 361, + 545, + 613 + ], + "type": "text", + "content": ". The high-quality 3D reconstructed models lead to final rendered RGB images with rich scene details and high visual quality. Six types of annotations are available for each RGB image. (1) The segmentation annotations of instances contain both visible and amodal instance masks. These are generated by the 3D simulation software, resulting in higher accuracy compared to manual annotations. Moreover, the occluded region mask annotations are more precise compared to human-annotated amodal masks which may vary between annotators. (2) Depth maps are produced to reflect the value of each pixel with regard to its distance from the relevant camera to the 3D object. The depth map registers distance for visible regions exclusively, excluding amodal regions. (3) The occlusion order specifies the list of other objects occluded by this one. (4) Accompanying high-quality 3D models are included. (5) The bounding boxes and area of both visible and amodal masks derived from corresponding masks are provided." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 622, + 421, + 633 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 622, + 421, + 633 + ], + "spans": [ + { + "bbox": [ + 306, + 622, + 421, + 633 + ], + "type": "text", + "content": "3.2. Dataset Generation" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 641, + 545, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 641, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 305, + 641, + 545, + 677 + ], + "type": "text", + "content": "A universal pipeline is designed to generate the synthetic dataset MUVA in three stages: building 3D models, placing 3D models, and capturing data, as illustrated in Fig. 3." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "content": "3D Model Building. In this stage, 3D models are created as the foundation for the 3D scene, as presented in Fig. 3 (a). This stage contains two steps: (1) capturing six differ" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 749, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 318, + 757 + ], + "type": "text", + "content": "23506" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 62, + 72, + 533, + 225 + ], + "blocks": [ + { + "bbox": [ + 62, + 72, + 533, + 225 + ], + "lines": [ + { + "bbox": [ + 62, + 72, + 533, + 225 + ], + "spans": [ + { + "bbox": [ + 62, + 72, + 533, + 225 + ], + "type": "image", + "image_path": "c88e1e52f8c996ef9612c1bdc613fda68e067c6956f483df054a648f62858de0.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 233, + 547, + 257 + ], + "lines": [ + { + "bbox": [ + 46, + 233, + 547, + 257 + ], + "spans": [ + { + "bbox": [ + 46, + 233, + 547, + 257 + ], + "type": "text", + "content": "Figure 4. The histogram of the number of instances for four parent categories (bags, others, bottles, boxes) and corresponding subcategories. Non-rigid categories are noted with star stripes. Best viewed in color." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 67, + 264, + 529, + 380 + ], + "blocks": [ + { + "bbox": [ + 67, + 264, + 529, + 380 + ], + "lines": [ + { + "bbox": [ + 67, + 264, + 529, + 380 + ], + "spans": [ + { + "bbox": [ + 67, + 264, + 529, + 380 + ], + "type": "table", + "html": "
DatasetPublicationData TypeMultiple Views# Image# InstanceScenarioSynthetic or Real3D ModelDepth# CategoriesResolution (pixels)
SAIL-VOS [13]CVPR'19video-111,6541,896,295daily lifesynthetic-✓1621M
SAIL-VOS 3D [14]CVPR'21video-237,6113,460,213daily lifesynthetic✓✓1781M
COCOA [40]CVPR'17image-5,00046,314daily lifereal--N/A0.28M
BSDSA [40]CVPR'17image-5003,739daily lifereal--N/A0.15M
DYCE [6]CVPR'18image-5,50085,975daily lifesynthetic--791M
KINS [27]CVPR'19image-14,991190,626streetreal--80.47M
D2SA [8]WACV'19image-5,60028,720shoppingreal--603M
COCOA-cls [8]WACV'19image-3,50110,562daily lifereal--800.28M
MUVAN/Aimage✓26,406198,573shoppingsynthetic✓✓202M
", + "image_path": "ccfc077a44903f135fe058ca2ca61b47bfecd03b9bec94b3f02e7897fe8dd882.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 387, + 546, + 410 + ], + "lines": [ + { + "bbox": [ + 46, + 387, + 546, + 410 + ], + "spans": [ + { + "bbox": [ + 46, + 387, + 546, + 410 + ], + "type": "text", + "content": "Table 1. Comparison with existing amodal instance segmentation datasets. # means the number of this item. Bold numbers denote the largest one in each column among image-level datasets." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 429, + 288, + 502 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 429, + 288, + 502 + ], + "spans": [ + { + "bbox": [ + 46, + 429, + 288, + 502 + ], + "type": "text", + "content": "ent images of each object to provide adequate information for 3D reconstruction, and (2) utilizing MAYA, a 3D modeling software, to reconstruct and manually refine the 3D objects iteratively by 3D artists. This process results in the reconstruction of 1801 distinct 3D objects, each with reconstructed shape and texture." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 510, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 510, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 510, + 289, + 715 + ], + "type": "text", + "content": "3D Model Placing. This stage involves generating 3D scenes by selecting and placing 3D object models. It comprises two steps: 3D model selection and placement, as depicted in Fig. 3 (b). First, a shelf is created as a platform for scene construction, and 3D models are randomly chosen from those reconstructed in the previous stage. Second, placement settings, including object number, orientation, and position, are varied randomly to enhance diversity. The number of objects can range from less than 10 to more than 10, and their upright or flat placement is randomized. Object positions are also randomized, ensuring they are within the shelf's range. Finally, Unity3D software is used to render the scene. The physical simulation utilizes non-deformable 3D models with collision detection to prevent object penetration. The scenes were illuminated uniformly and gravity was applied to mimic realistic conditions. Creating all 1801 3D models required approximately" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 429, + 547, + 464 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 429, + 547, + 464 + ], + "spans": [ + { + "bbox": [ + 304, + 429, + 547, + 464 + ], + "type": "text", + "content": "600 hours with a 20-minute time frame for each model. The cost of generating the models totaled approximately 15,000 USD at a rate of 25 USD per hour for each 3D artist." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 466, + 547, + 537 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 466, + 547, + 537 + ], + "spans": [ + { + "bbox": [ + 304, + 466, + 547, + 537 + ], + "type": "text", + "content": "Data Capture. The simulated scene depicted in Fig. 3 (c) provides various types of data for sampling. Six cameras are positioned in the front to capture sparse views and simulate the self-checkout setting, ensuring the applicability of MUVA to real-life scenarios. For each view, RGB images and numerous annotations are generated." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 539, + 547, + 575 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 539, + 547, + 575 + ], + "spans": [ + { + "bbox": [ + 304, + 539, + 547, + 575 + ], + "type": "text", + "content": "The above dataset generation pipeline is adaptable for creating datasets for other vision tasks, such as indoor 3D reconstruction [4] and person re-identification [31]." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 586, + 410, + 597 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 586, + 410, + 597 + ], + "spans": [ + { + "bbox": [ + 306, + 586, + 410, + 597 + ], + "type": "text", + "content": "3.3. Dataset Statistics" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "type": "text", + "content": "MUVA dataset comprises 26,406 images with 198,573 instances categorized into four parent categories (bags, bottles, boxes, and others), and 20 sub-categories that include both rigid and non-rigid objects. The instance ratio of each category is presented in Fig. 4. The dataset contains " + }, + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "type": "inline_equation", + "content": "27.41\\%" + }, + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "type": "text", + "content": " non-rigid objects, such as the \"Plastic Bag,\" which provides shape variations. The proposed dataset includes high-resolution images of " + }, + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "type": "inline_equation", + "content": "1920 \\times 1080" + }, + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "type": "text", + "content": " pixels, providing rich details of the objects' edges and surfaces." + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "23507" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 78, + 82, + 517, + 232 + ], + "blocks": [ + { + "bbox": [ + 78, + 82, + 517, + 232 + ], + "lines": [ + { + "bbox": [ + 78, + 82, + 517, + 232 + ], + "spans": [ + { + "bbox": [ + 78, + 82, + 517, + 232 + ], + "type": "image", + "image_path": "59ecc73200a81a1ca44d48210edc61a7caa5cce1a99ca61c57597a2d3b22de22.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 243, + 547, + 277 + ], + "lines": [ + { + "bbox": [ + 46, + 243, + 547, + 277 + ], + "spans": [ + { + "bbox": [ + 46, + 243, + 547, + 277 + ], + "type": "text", + "content": "Figure 5. Overall architecture of our method. There are two stages in our method, including the Feature Extraction Stage and the Multi-view Aggregation Stage. The first stage aims to extract the features of each instance from all views. The second stage utilizes the relationship of features at the instance level and view level, respectively, to generate accurate predictions." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 295, + 236, + 308 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 295, + 236, + 308 + ], + "spans": [ + { + "bbox": [ + 47, + 295, + 236, + 308 + ], + "type": "text", + "content": "3.4. Comparison with Existing Datasets" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 313, + 290, + 494 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 313, + 290, + 494 + ], + "spans": [ + { + "bbox": [ + 46, + 313, + 290, + 494 + ], + "type": "text", + "content": "Tab. 1 presents a comparison between MUVA and other AIS datasets, including video and image-level datasets such as COCOA [40], BSDSA [40], DYCE [6], KINS [27], D2SA [8] and COCOA-cls [8]. MUVA stands out as the only dataset specifically designed for the multi-view AIS task and the only synthetic image-level dataset that provides 3D models. The 3D models used to build the dataset are publicly available to support new methods for the AIS task. Additionally, MUVA and D2SA are the only two datasets for the shopping scenario. MUVA's synthetic nature leads to consistent and higher-quality annotations than human-annotated datasets. Moreover, MUVA has the largest number of images and instances among image-level datasets, and is the only dataset at the image level that contains depth maps, which can potentially help with the AIS task." + } + ] + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 69, + 504, + 272, + 575 + ], + "blocks": [ + { + "bbox": [ + 69, + 504, + 272, + 575 + ], + "lines": [ + { + "bbox": [ + 69, + 504, + 272, + 575 + ], + "spans": [ + { + "bbox": [ + 69, + 504, + 272, + 575 + ], + "type": "table", + "html": "
Datasetsimplicity ↓convexity ↓
visibleamodalvisibleamodal
BSDS-A0.7180.8340.6160.643
COCO-A0.7460.8560.6580.685
KINS0.7090.8300.6100.639
MUVA0.9590.8010.9230.963
", + "image_path": "82e130be56a55d06674a770470c441d6d104fa6cdbed62ba50f0c7652fd45ff7.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 582, + 287, + 616 + ], + "lines": [ + { + "bbox": [ + 47, + 582, + 287, + 616 + ], + "spans": [ + { + "bbox": [ + 47, + 582, + 287, + 616 + ], + "type": "text", + "content": "Table 2. Complexity is evaluated through simplicity and convexity metrics. Small values of these metrics indicate a complex dataset. A circle shape yields the maximum value of 1.0 for both metrics." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "content": "Shape Complexity. To assess the shape complexity of mask annotations contained in MUVA, metrics proposed by COCOA [40] is used. These metrics include convexity and simplicity for both visible and amodal masks. As shown in Tab. 2, MUVA has the lowest shape simplicity (0.801) and the highest convexity (0.963) of amodal masks. The high convexity can be attributed to the presence of goods such" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 295, + 547, + 356 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 295, + 547, + 356 + ], + "spans": [ + { + "bbox": [ + 304, + 295, + 547, + 356 + ], + "type": "text", + "content": "as bags, bottles, and boxes, which possess naturally convex shapes. Conversely, the low simplicity confirms that the shapes within MUVA are complex. For instance, a plastic bag with zigzagged boundaries exhibits high convexity but low simplicity." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 363, + 388, + 376 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 363, + 388, + 376 + ], + "spans": [ + { + "bbox": [ + 306, + 363, + 388, + 376 + ], + "type": "text", + "content": "3.5. Applications" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 381, + 547, + 501 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 381, + 547, + 501 + ], + "spans": [ + { + "bbox": [ + 304, + 381, + 547, + 501 + ], + "type": "text", + "content": "MUVA provides diverse annotations that can be used for multiple research tasks. For example, using instance IDs from different viewpoints can lead to a new task of multi-view amodal instance segmentation (MAIS), which involves matching and segmenting the same instance from multiple viewpoints. High-quality 3D models can be used for single/multiple-view 3D reconstruction. The provided relative depth order annotation allows for occlusion order prediction. Finally, the depth map from the object to the camera can be utilized for depth estimation." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 512, + 361, + 523 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 512, + 361, + 523 + ], + "spans": [ + { + "bbox": [ + 306, + 512, + 361, + 523 + ], + "type": "text", + "content": "4. Method" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 532, + 547, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 532, + 547, + 605 + ], + "spans": [ + { + "bbox": [ + 304, + 532, + 547, + 605 + ], + "type": "text", + "content": "This paper focuses on the newly formulated multi-view amodal instance segmentation (MAIS) task. This section proposes a network designed for the MAIS task, named Multi-view Amodal Segmentation Transformer (MAS-Former). The task definition, overall architecture, and the proposed new modules are introduced in the following." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 611, + 373, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 611, + 373, + 623 + ], + "spans": [ + { + "bbox": [ + 306, + 611, + 373, + 623 + ], + "type": "text", + "content": "4.1. Overview" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 629, + 545, + 666 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 545, + 666 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 545, + 666 + ], + "type": "text", + "content": "Problem Definition. Given " + }, + { + "bbox": [ + 304, + 629, + 545, + 666 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 629, + 545, + 666 + ], + "type": "text", + "content": " input images from " + }, + { + "bbox": [ + 304, + 629, + 545, + 666 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 629, + 545, + 666 + ], + "type": "text", + "content": " viewpoints, the MAIS task aims to predict " + }, + { + "bbox": [ + 304, + 629, + 545, + 666 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 304, + 629, + 545, + 666 + ], + "type": "text", + "content": " instance-level segmentation masks for interested objects in each image." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 666, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 666, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 666, + 547, + 713 + ], + "type": "text", + "content": "Overall Architecture. The whole pipeline of the proposed method contains two stages, including the Feature Extraction Stage (FES) and the Multi-view Aggregation Stage (MAS). (1) The FES extracts features of each instance" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23508" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 286, + 143 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 286, + 143 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 286, + 143 + ], + "type": "text", + "content": "from all angles. (2) The MAS takes the instances' feature from FES as input and optimizes from two aspects, including aggregating all instances' features of the same view and all views' features of the same instance. Finally, the amodal instance predictions of objects in all images are generated after fusion." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 152, + 186, + 165 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 152, + 186, + 165 + ], + "spans": [ + { + "bbox": [ + 48, + 152, + 186, + 165 + ], + "type": "text", + "content": "4.2. Feature Extraction Stage" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 171, + 286, + 313 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 171, + 286, + 313 + ], + "spans": [ + { + "bbox": [ + 48, + 171, + 286, + 313 + ], + "type": "text", + "content": "This stage aims to extract features from all views simultaneously. As shown in Fig. 5, the Backbone takes for " + }, + { + "bbox": [ + 48, + 171, + 286, + 313 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 48, + 171, + 286, + 313 + ], + "type": "text", + "content": " images as input and extracts representative features for " + }, + { + "bbox": [ + 48, + 171, + 286, + 313 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 48, + 171, + 286, + 313 + ], + "type": "text", + "content": " instances, including low-level structural details and high-level semantic information. Next, the CNN Decoder up-samples the representative features and generates multilevel features containing all objects' information. Then a Transformer Decoder is employed to output features " + }, + { + "bbox": [ + 48, + 171, + 286, + 313 + ], + "type": "inline_equation", + "content": "F_{FES}" + }, + { + "bbox": [ + 48, + 171, + 286, + 313 + ], + "type": "text", + "content": " corresponding to all objects in all views. Bipartite matching [2] is used to find the correspondence between predictions and supervisions, to specify the view id and instance id of each feature." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 323, + 208, + 336 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 323, + 208, + 336 + ], + "spans": [ + { + "bbox": [ + 48, + 323, + 208, + 336 + ], + "type": "text", + "content": "4.3. Multi-view Aggregation Stage" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 342, + 286, + 389 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 342, + 286, + 389 + ], + "spans": [ + { + "bbox": [ + 48, + 342, + 286, + 389 + ], + "type": "text", + "content": "As shown in Fig. 5, this stage aims to enhance the extracted features " + }, + { + "bbox": [ + 48, + 342, + 286, + 389 + ], + "type": "inline_equation", + "content": "F_{FES}" + }, + { + "bbox": [ + 48, + 342, + 286, + 389 + ], + "type": "text", + "content": " from two aspects, including view-level and instance-level. Two branches are designed for the two aspects, respectively." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 390, + 286, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 390, + 286, + 616 + ], + "spans": [ + { + "bbox": [ + 48, + 390, + 286, + 616 + ], + "type": "text", + "content": "View-level Aggregation. This branch aims to utilize the relationship between features of all instances in the same view for enhancing each instance's feature quality. Firstly, for input features " + }, + { + "bbox": [ + 48, + 390, + 286, + 616 + ], + "type": "inline_equation", + "content": "F_{FES}" + }, + { + "bbox": [ + 48, + 390, + 286, + 616 + ], + "type": "text", + "content": " including all objects in all views, an View Feature Grouping module takes features of the same view into the same group. Then the View-level Attention module learns the correlation between all instances' features in the same view. Finally, the feature of each instance is enhanced by integrating all correlated instances' features in the same view. Here the correlation between different features is computed by cosine similarity. And the self-attention [32] is used to construct this module. Please refer to our supplementary material for detailed explanations of the network. Besides, this module requires objects in different views could be identified and matched. To achieve this, for each instance, both the view id and the instance id are predicted by the network and supervised by using the bipartite matching [2] to match between the prediction and ground truth." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 617, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 617, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 617, + 286, + 713 + ], + "type": "text", + "content": "Instance-level Aggregation. This module aims to use features of the same instance in all views to improve the feature quality of each instance. First, the Instance Feature Grouping module takes features of the same instance across all views to the same group. Next, for each group, the Instance-level Attention module learns correlations between features of the same instance in different views and integrates associated features by using the self-attention [32]" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 308, + 73, + 356, + 83 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 73, + 356, + 83 + ], + "spans": [ + { + "bbox": [ + 308, + 73, + 356, + 83 + ], + "type": "text", + "content": "mechanism." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 308, + 85, + 545, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 85, + 545, + 144 + ], + "spans": [ + { + "bbox": [ + 308, + 85, + 545, + 144 + ], + "type": "text", + "content": "Finally, a CNN-based fuse layer is used to merge the output features of two branches for the final prediction of amodal masks. With the aggregation of two branches, the feature representations of all instances can be enhanced, and more precise amodal segmentation results can be obtained." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 308, + 159, + 385, + 172 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 159, + 385, + 172 + ], + "spans": [ + { + "bbox": [ + 308, + 159, + 385, + 172 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 308, + 179, + 545, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 179, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 308, + 179, + 545, + 251 + ], + "type": "text", + "content": "This section first compares the newly proposed method MASFormer with existing single-view-based state-of-the-art AIS methods on the proposed MUVA dataset. Then the ablation studies are conducted to show the effectiveness of amount and order for the input viewpoints and components of the proposed method." + } + ] + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 328, + 262, + 526, + 375 + ], + "blocks": [ + { + "bbox": [ + 328, + 262, + 526, + 375 + ], + "lines": [ + { + "bbox": [ + 328, + 262, + 526, + 375 + ], + "spans": [ + { + "bbox": [ + 328, + 262, + 526, + 375 + ], + "type": "table", + "html": "
MethodPublicationAPAP50AP75AR
Mask-RCNN [11]ICCV'1717.226.618.748.8
ORCNN [8]WACV'197.825.92.124.7
SLN [38]ACM MM'196.920.25.622.9
DeepSnake [26]CVPR'207.711.97.423.8
BCNet [16]CVPR'2123.128.925.040.9
ShapeDict [33]AAAI'219.936.01.327.8
E2EC [37]CVPR'2211.815.712.925.5
Baseline (1 view)CVPR'2217.826.118.029.2
Baseline (6 views)CVPR'2222.935.522.336.4
Ours (1 view)N/A25.638.025.641.2
Ours (6 views)N/A39.455.940.351.8
", + "image_path": "1609ecd625b9c222dc14a25ebc64e13e4e470a5ccdffbe006110b003fa20c639.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + } + ], + "index": 11 + }, + { + "type": "table", + "bbox": [ + 318, + 429, + 537, + 490 + ], + "blocks": [ + { + "bbox": [ + 308, + 383, + 545, + 404 + ], + "lines": [ + { + "bbox": [ + 308, + 383, + 545, + 404 + ], + "spans": [ + { + "bbox": [ + 308, + 383, + 545, + 404 + ], + "type": "text", + "content": "Table 3. Compared with state-of-the-art methods on MUVA. In each column, the best is in bold, and the second-best is underlined." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 318, + 429, + 537, + 490 + ], + "lines": [ + { + "bbox": [ + 318, + 429, + 537, + 490 + ], + "spans": [ + { + "bbox": [ + 318, + 429, + 537, + 490 + ], + "type": "table", + "html": "
MethodResNet-50ResNet-101ResNeXt-101
MaskRCNN17.219.119.8
BCNet23.125.326.6
E2EC11.814.215.9
Ours (6 views)39.442.543.0
", + "image_path": "fdf2b7a1905c5d9beec339279d7839e42c157d357f23f1620e21481431fb63ef.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_body" + } + ], + "index": 13 + }, + { + "bbox": [ + 320, + 498, + 531, + 508 + ], + "lines": [ + { + "bbox": [ + 320, + 498, + 531, + 508 + ], + "spans": [ + { + "bbox": [ + 320, + 498, + 531, + 508 + ], + "type": "text", + "content": "Table 4. Performance of methods with stronger backbones." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 308, + 521, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 521, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 521, + 545, + 712 + ], + "type": "text", + "content": "Experimental Settings. The baseline method only contains the first stage FES in the proposed method MAS-Former, which is implemented following the video instance segmentation method Mask2Former [3] as an instantiation. The baseline method can take multi-view images as input and outputs amodal segmentation masks, the same as MAS-Former. ResNet-FPN-50 [12] is employed as the backbone for all methods. The results are evaluated using the AP and AR metric, commonly used to measure the precision and recall of prediction. For fairness, all experiments use the same training dataset of MUVA to train and the same validation dataset of MUVA to validate. The ground truth of all methods is the same, including the bounding boxes and masks for amodal and visible regions, image ids, and instance ids. The ground-truth camera viewpoint information and 3D models are not used for fairness." + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "text", + "content": "23509" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 75, + 71, + 521, + 258 + ], + "blocks": [ + { + "bbox": [ + 75, + 71, + 521, + 258 + ], + "lines": [ + { + "bbox": [ + 75, + 71, + 521, + 258 + ], + "spans": [ + { + "bbox": [ + 75, + 71, + 521, + 258 + ], + "type": "image", + "image_path": "2158de3ad8dcc0542226875e4647873673e85313d756928b263050f6feef2b25.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 265, + 547, + 309 + ], + "lines": [ + { + "bbox": [ + 46, + 265, + 547, + 309 + ], + "spans": [ + { + "bbox": [ + 46, + 265, + 547, + 309 + ], + "type": "text", + "content": "Figure 6. Visualization comparisons between BCNet [16] and ours on MUVA, trained with one viewpoint (1V) and six viewpoints (6V). For masks, different colors denote different instances, and the same instance in different angles has the same color. Red circles indicate regions should be focused. Zoom in for a better view. In the first and third columns, even if a bottle is severely occluded, it can be predicted accurately by our method. Moreover, our method trained with 6 views performs better than training with a single view." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 328, + 271, + 342 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 328, + 271, + 342 + ], + "spans": [ + { + "bbox": [ + 47, + 328, + 271, + 342 + ], + "type": "text", + "content": "5.1. Multi-view Amodal Instance Segmentation" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 350, + 288, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 350, + 288, + 434 + ], + "spans": [ + { + "bbox": [ + 46, + 350, + 288, + 434 + ], + "type": "text", + "content": "Tab. 3 shows the comparison results of some existing AIS methods on MUVA. Several state-of-the-art methods designed for single-view datasets are compared. For baseline and the proposed method MASFormer, two kinds of input are used during training, one is a single view, and the other is six. Note that the amount of training data is the same for these two settings." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 438, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 438, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 438, + 288, + 714 + ], + "type": "text", + "content": "We compare the results at three levels, including one-view, one vs. six views, and six-view levels. (1) As shown in Tab. 3, when only using one view for training, our proposed method MASFormer achieves the best performance " + }, + { + "bbox": [ + 46, + 438, + 288, + 714 + ], + "type": "inline_equation", + "content": "(25.6\\% AP, 38.0\\% AP_{50}, 25.6\\% AP_{75}, 41.2\\% AR)" + }, + { + "bbox": [ + 46, + 438, + 288, + 714 + ], + "type": "text", + "content": " on all metrics. MASFormer outperforms the best performance of single-view-based methods with " + }, + { + "bbox": [ + 46, + 438, + 288, + 714 + ], + "type": "inline_equation", + "content": "2.7\\% AP, 2.0\\% AP_{50}, 0.6\\% AP_{75}" + }, + { + "bbox": [ + 46, + 438, + 288, + 714 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 438, + 288, + 714 + ], + "type": "inline_equation", + "content": "0.2\\% AR" + }, + { + "bbox": [ + 46, + 438, + 288, + 714 + ], + "type": "text", + "content": ". The results demonstrate the effectiveness of the proposed view-level attention module, which can learn the relationship between different instances of the same view and improve the amodal prediction with the help of a learned relationship. (2) Both ours and the baseline method achieve better performance when using six views than one view for training. The results show that even with the same training data, using more views as input for training can improve the prediction. (3) When both methods use six views for training, our method can outperform the baseline method with " + }, + { + "bbox": [ + 46, + 438, + 288, + 714 + ], + "type": "inline_equation", + "content": "16.5\\%" + }, + { + "bbox": [ + 46, + 438, + 288, + 714 + ], + "type": "text", + "content": " AP. The results show the effectiveness of the proposed instance-level attention module, which learns and benefits from the relationship between different views of the same instance. Besides, the performance of methods with stronger backbones is shown in Tab. 4. Stronger backbones bring improvements for all" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 305, + 329, + 545, + 354 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 329, + 545, + 354 + ], + "spans": [ + { + "bbox": [ + 305, + 329, + 545, + 354 + ], + "type": "text", + "content": "methods, while the proposed MASFormer still achieves the best performance. Qualitative results are shown in Fig. 6." + } + ] + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 312, + 363, + 544, + 415 + ], + "blocks": [ + { + "bbox": [ + 312, + 363, + 544, + 415 + ], + "lines": [ + { + "bbox": [ + 312, + 363, + 544, + 415 + ], + "spans": [ + { + "bbox": [ + 312, + 363, + 544, + 415 + ], + "type": "table", + "html": "
SettingTraining DatasetTesting DatasetAP
1D2SAtrainD2SAval63.5
2MUVAtrainD2SAval41.9
3D2SAtrain + MUVAtrainD2SAval68.4
", + "image_path": "b049bc092b6d8bc9041ef9b57f1bb8de1a1d0f5f48633f5707de11d2ad488a88.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 422, + 547, + 467 + ], + "lines": [ + { + "bbox": [ + 305, + 422, + 547, + 467 + ], + "spans": [ + { + "bbox": [ + 305, + 422, + 547, + 467 + ], + "type": "text", + "content": "Table 5. Performance of MASFormer evaluated on the validation set of D2SA dataset and trained with different combinations of source-domain datasets for training. For the two datasets, only data of overlapped categories are used." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 479, + 512, + 491 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 479, + 512, + 491 + ], + "spans": [ + { + "bbox": [ + 306, + 479, + 512, + 491 + ], + "type": "text", + "content": "5.2. Generalization to Real-world Scenarios" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 498, + 545, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 498, + 545, + 533 + ], + "spans": [ + { + "bbox": [ + 304, + 498, + 545, + 533 + ], + "type": "text", + "content": "In this section, we demonstrate the generalization ability of the proposed dataset and method on real-world scenarios under single-view and multi-view settings, respectively." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 534, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 534, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 534, + 546, + 713 + ], + "type": "text", + "content": "Single-view Generalization. To validate generalization ability in real-world scenarios, the MUVA dataset is utilized under a single-view setting. To be specific, we employ settings of the domain generalization [39, 10, 15] task to evaluate the generalization ability of learning from a source domain, typically synthetic datasets, to out-of-distribution target domains like real-world datasets. Specifically, the MUVA synthetic dataset and real-world AIS dataset D2SA [8] are used in this study. D2SA contains 60 categories, of which 18 categories overlap with MUVA. More information about the category labels can be found in the supplementary material. The following experiments only consider data from the overlapping categories. Three settings were adopted as presented in Tab. 5. Firstly, MASFormer is trained and evaluated on the train and validation sets of" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "23510" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "content": "D2SA datasets, demonstrating its ability to generalize well on real-world data. Secondly, MASFormer is trained on the synthetic MUVA dataset and evaluated on the real-world dataset D2SA, with results validating the generalizability of the synthetic MUVA dataset. Lastly, mixing D2SA and MUVA for training lead to a " + }, + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "inline_equation", + "content": "4.9\\%" + }, + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "content": " AP improvement, indicating the benefits of using MUVA in a real-world scenario." + } + ] + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 51, + 167, + 287, + 297 + ], + "blocks": [ + { + "bbox": [ + 51, + 167, + 287, + 297 + ], + "lines": [ + { + "bbox": [ + 51, + 167, + 287, + 297 + ], + "spans": [ + { + "bbox": [ + 51, + 167, + 287, + 297 + ], + "type": "image", + "image_path": "e726f945697326db7618159e11eb156c1abeeae538bdbad3711cdcfd37f2a0a1.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 304, + 288, + 337 + ], + "lines": [ + { + "bbox": [ + 46, + 304, + 288, + 337 + ], + "spans": [ + { + "bbox": [ + 46, + 304, + 288, + 337 + ], + "type": "text", + "content": "Figure 7. Qualitative results of a real-world case. Red circles indicate differences between ours and BCNet. Zoom in for a better view." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 347, + 287, + 502 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 347, + 287, + 502 + ], + "spans": [ + { + "bbox": [ + 46, + 347, + 287, + 502 + ], + "type": "text", + "content": "Multi-view Generalization. Considering there is no existing multi-view real-world AIS dataset, we construct a real-world shopping scenario to obtain multi-view data for validating the generalization ability of the proposed dataset and method. Images are captured from the left, middle, and right sides, respectively. MASFormer trained with six views and BCNet are used. And the train set of MUVA is utilized for training. As shown in Fig. 7, MASFormer can obtain good amodal segmentation results, demonstrating the generalization ability of MUVA to real-world scenarios. Moreover, when compared with BCNet, MASFormer performs better consistently on all viewpoints, validating its potential for generalizing to the real-world scene." + } + ] + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 58, + 512, + 278, + 639 + ], + "blocks": [ + { + "bbox": [ + 58, + 512, + 278, + 639 + ], + "lines": [ + { + "bbox": [ + 58, + 512, + 278, + 639 + ], + "spans": [ + { + "bbox": [ + 58, + 512, + 278, + 639 + ], + "type": "table", + "html": "
Views Order# ViewsAPAP50AP75AR
N/A125.638.025.639.2
Fixed Order226.238.026.339.8
328.042.927.740.9
430.945.630.943.5
534.149.034.747.4
637.953.938.651.4
Random Order226.939.527.140.4
328.441.728.442.9
432.846.633.445.6
536.952.737.250.5
639.455.940.351.8
", + "image_path": "cdcfc7a82622daf273c7226a98962a187c5537b6f15a5322c59ddb6ebbf9cb00.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 673, + 141, + 687 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 673, + 141, + 687 + ], + "spans": [ + { + "bbox": [ + 47, + 673, + 141, + 687 + ], + "type": "text", + "content": "5.3. Ablation Study" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 689, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 288, + 713 + ], + "type": "text", + "content": "We conducted ablation study experiments for MAS-Former, examining the impact of the number and order of" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 72, + 544, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 544, + 95 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 544, + 95 + ], + "type": "text", + "content": "input viewpoints, the effectiveness of attention modules, and computational cost." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "spans": [ + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "text", + "content": "Viewpoints Count and Order. Tab 6 presents some combinations of the number and order of input viewpoints used for training in the proposed MASFormer method. The same amount of training data is used for all experiments. Performance consistently improves as the number of input views increases, regardless of whether their order is fixed (rows # 2 to # 6) or random (rows # 7 to # 11). These results show that using more views for training can improve performance and multi-view data is crucial for amodal instance segmentation. When the number of input views is constant, the impact of the input views' order is analyzed below. As shown in Tab. 6, results of random input order outperform fixed order ones with the equal number of input views. For example, random order improves the " + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "inline_equation", + "content": "AP" + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "text", + "content": " metric with the following percentages compared to fixed order: " + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "inline_equation", + "content": "0.7\\%" + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "text", + "content": " (2 views), " + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "inline_equation", + "content": "0.4\\%" + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "text", + "content": " (3 views), " + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "inline_equation", + "content": "1.9\\%" + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "text", + "content": " (4 views), " + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "inline_equation", + "content": "2.8\\%" + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "text", + "content": " (5 views) and " + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "inline_equation", + "content": "1.5\\%" + }, + { + "bbox": [ + 304, + 96, + 545, + 334 + ], + "type": "text", + "content": " (6 views). Results show that randomizing input image ordering of various viewpoints leads to increased training sample distribution and improved effectiveness." + } + ] + } + ], + "index": 9 + }, + { + "type": "table", + "bbox": [ + 324, + 344, + 531, + 401 + ], + "blocks": [ + { + "bbox": [ + 46, + 647, + 287, + 669 + ], + "lines": [ + { + "bbox": [ + 46, + 647, + 287, + 669 + ], + "spans": [ + { + "bbox": [ + 46, + 647, + 287, + 669 + ], + "type": "text", + "content": "Table 6. Effect of fixing views input order and views amount. In each column, the best is in bold, and the second-best is underlined." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 324, + 344, + 531, + 401 + ], + "lines": [ + { + "bbox": [ + 324, + 344, + 531, + 401 + ], + "spans": [ + { + "bbox": [ + 324, + 344, + 531, + 401 + ], + "type": "table", + "html": "
IndexView-levelInstance-levelAPAP50AP75AR
122.935.522.336.4
2✓28.743.128.341.6
3✓34.149.034.747.4
4✓✓39.455.940.351.8
", + "image_path": "c77b30f25e9d0e4ad5937de54c2c430af5d379d691d86b70725073794cb636ec.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "spans": [ + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "text", + "content": "Attention Modules. Tab. 7 shows the ablation study of proposed attention modules proposed in our MASFormer method, using six input views with random order. The proposed view-level attention module improves " + }, + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "inline_equation", + "content": "AP" + }, + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "text", + "content": " performance from " + }, + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "inline_equation", + "content": "22.9\\%" + }, + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "inline_equation", + "content": "28.7\\%" + }, + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "text", + "content": " by learning feature relationships within the same view. Instance-level attention module achieves an " + }, + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "inline_equation", + "content": "11.2\\%" + }, + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "text", + "content": " improvement by utilizing multi-view features of the same instance. Both attention modules combined result in a " + }, + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "inline_equation", + "content": "39.4\\%" + }, + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "inline_equation", + "content": "AP" + }, + { + "bbox": [ + 304, + 428, + 545, + 548 + ], + "type": "text", + "content": " performance, surpassing individual settings." + } + ] + } + ], + "index": 12 + }, + { + "type": "table", + "bbox": [ + 326, + 558, + 529, + 606 + ], + "blocks": [ + { + "bbox": [ + 306, + 408, + 541, + 419 + ], + "lines": [ + { + "bbox": [ + 306, + 408, + 541, + 419 + ], + "spans": [ + { + "bbox": [ + 306, + 408, + 541, + 419 + ], + "type": "text", + "content": "Table 7. Effect of two attention modules in the proposed method." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 326, + 558, + 529, + 606 + ], + "lines": [ + { + "bbox": [ + 326, + 558, + 529, + 606 + ], + "spans": [ + { + "bbox": [ + 326, + 558, + 529, + 606 + ], + "type": "table", + "html": "
MethodFrameworkGPU MemFPSTimeAP
BCNetCNN4G8.34h23.1
BaselineTransformer9G6.56h22.9
OursTransformer13G3.78h39.4
", + "image_path": "1ecff08027f2d8610253e7b0726df536186535e116a76cb0c04b928c8c7ea17a.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_body" + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 613, + 544, + 635 + ], + "lines": [ + { + "bbox": [ + 304, + 613, + 544, + 635 + ], + "spans": [ + { + "bbox": [ + 304, + 613, + 544, + 635 + ], + "type": "text", + "content": "Table 8. Comparison of computational cost and the performance. Time means the training time." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 647, + 423, + 659 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 647, + 423, + 659 + ], + "spans": [ + { + "bbox": [ + 306, + 647, + 423, + 659 + ], + "type": "text", + "content": "5.4. Computational Cost" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "Tab. 8 compares the computational cost. The ResNet50-FPN backbone is used for all methods. The FPS is the average of all images in the validation dataset. Compared to other methods, our method exhibits superior performance at" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23511" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 288, + 97 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 288, + 97 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 288, + 97 + ], + "type": "text", + "content": "the expense of higher computational cost due to the use of Transformer framework." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 109, + 200, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 109, + 200, + 121 + ], + "spans": [ + { + "bbox": [ + 47, + 109, + 200, + 121 + ], + "type": "text", + "content": "6. Limitation and Conclusion" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 129, + 289, + 261 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 129, + 289, + 261 + ], + "spans": [ + { + "bbox": [ + 46, + 129, + 289, + 261 + ], + "type": "text", + "content": "Limitations of this paper include the consideration of only one scenario, shopping, and a high computational cost of the proposed method. Future research should aim to expand the dataset to include other scenarios and develop a more efficient network that incorporates additional information such as 3D models from MUVA. As for the conclusion, this paper introduces a novel task called multi-view amodal instance segmentation (MAIS) in the shopping scenario. To facilitate research in this area, a new synthetic dataset, MUVA, is introduced along with a proposed method that utilizes multi-view information." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 274, + 144, + 287 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 274, + 144, + 287 + ], + "spans": [ + { + "bbox": [ + 47, + 274, + 144, + 287 + ], + "type": "text", + "content": "Acknowledgments" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 294, + 287, + 354 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 294, + 287, + 354 + ], + "spans": [ + { + "bbox": [ + 47, + 294, + 287, + 354 + ], + "type": "text", + "content": "This work was partially supported by the Natural Science Foundation of China under contract 62088102. This work was also partially supported by Qualcomm. We also acknowledge High-Performance Computing Platform of Peking University for providing computational resources." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 367, + 106, + 379 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 367, + 106, + 379 + ], + "spans": [ + { + "bbox": [ + 48, + 367, + 106, + 379 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 387, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 53, + 387, + 287, + 442 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 387, + 287, + 442 + ], + "spans": [ + { + "bbox": [ + 53, + 387, + 287, + 442 + ], + "type": "text", + "content": "[1] Seunghyeok Back, Joosoon Lee, Taewon Kim, Sangjun Noh, Raeyoung Kang, Seongho Bak, and Kyoobin Lee. Unseen object amodal instance segmentation via hierarchical occlusion modeling. In International Conference on Robotics and Automation, pages 5085-5092, 2022." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 444, + 287, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 444, + 287, + 498 + ], + "spans": [ + { + "bbox": [ + 53, + 444, + 287, + 498 + ], + "type": "text", + "content": "[2] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 213-229, 2020." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 500, + 287, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 500, + 287, + 555 + ], + "spans": [ + { + "bbox": [ + 53, + 500, + 287, + 555 + ], + "type": "text", + "content": "[3] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1290–1299, 2022." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 556, + 287, + 610 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 556, + 287, + 610 + ], + "spans": [ + { + "bbox": [ + 53, + 556, + 287, + 610 + ], + "type": "text", + "content": "[4] Angela Dai, Angel X Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. ScanNet: Richly-annotated 3D reconstructions of indoor scenes. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5828-5839, 2017." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 613, + 287, + 666 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 613, + 287, + 666 + ], + "spans": [ + { + "bbox": [ + 53, + 613, + 287, + 666 + ], + "type": "text", + "content": "[5] Kaiwen Duan, Song Bai, Lingxi Xie, Honggang Qi, Qingming Huang, and Qi Tian. CenterNet: Keypoint triplets for object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6569-6578, 2019." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 53, + 669, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 669, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 53, + 669, + 287, + 713 + ], + "type": "text", + "content": "[6] Kiana Ehsani, Roozbeh Mottaghi, and Ali Farhadi. SeGAN: Segmenting and generating the invisible. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6144-6153, 2018." + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 26, + "blocks": [ + { + "bbox": [ + 312, + 73, + 545, + 126 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 73, + 545, + 126 + ], + "spans": [ + { + "bbox": [ + 312, + 73, + 545, + 126 + ], + "type": "text", + "content": "[7] Patrick Follmann, Tobias Bottger, Philipp Hartinger, Rebecca Konig, and Markus Ulrich. MVtec D2S: Densely segmented supermarket dataset. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 569-585, 2018." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 312, + 129, + 545, + 193 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 129, + 545, + 193 + ], + "spans": [ + { + "bbox": [ + 312, + 129, + 545, + 193 + ], + "type": "text", + "content": "[8] Patrick Follmann, Rebecca König, Philipp Hartinger, Michael Klostermann, and Tobias Böttger. Learning to see the invisible: End-to-end trainable amodal instance segmentation. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1328-1336, 2019." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 312, + 195, + 545, + 248 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 195, + 545, + 248 + ], + "spans": [ + { + "bbox": [ + 312, + 195, + 545, + 248 + ], + "type": "text", + "content": "[9] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the KITTI vision benchmark suite. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3354-3361, 2012." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 250, + 545, + 282 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 250, + 545, + 282 + ], + "spans": [ + { + "bbox": [ + 307, + 250, + 545, + 282 + ], + "type": "text", + "content": "[10] Ishaan Gulrajani and David Lopez-Paz. In search of lost domain generalization. In International Conference on Learning Representations, 2021." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 283, + 545, + 326 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 283, + 545, + 326 + ], + "spans": [ + { + "bbox": [ + 307, + 283, + 545, + 326 + ], + "type": "text", + "content": "[11] Kaiming He, Georgia Gkioxari, Piotr Dólar, and Ross Girshick. Mask R-CNN. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2961-2969, 2017." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 327, + 545, + 370 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 327, + 545, + 370 + ], + "spans": [ + { + "bbox": [ + 308, + 327, + 545, + 370 + ], + "type": "text", + "content": "[12] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 372, + 545, + 436 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 372, + 545, + 436 + ], + "spans": [ + { + "bbox": [ + 308, + 372, + 545, + 436 + ], + "type": "text", + "content": "[13] Yuan-Ting Hu, Hong-Shuo Chen, Kexin Hui, Jia-Bin Huang, and Alexander G Schwing. SAIL-VOS: Semantic amodal instance level video object segmentation - a synthetic dataset and baselines. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3105-3115, 2019." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 437, + 545, + 502 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 437, + 545, + 502 + ], + "spans": [ + { + "bbox": [ + 308, + 437, + 545, + 502 + ], + "type": "text", + "content": "[14] Yuan-Ting Hu, Jiahong Wang, Raymond A. Yeh, and Alexander G. Schwing. SAIL-VOS 3D: A synthetic dataset and baselines for object detection and 3D mesh reconstruction from video data. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops, pages 3359-3369, 2021." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 504, + 545, + 547 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 504, + 545, + 547 + ], + "spans": [ + { + "bbox": [ + 308, + 504, + 545, + 547 + ], + "type": "text", + "content": "[15] Xueying Jiang, Jiaxing Huang, Sheng Jin, and Shijian Lu. Domain generalization via balancing training difficulty and model capability. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2023." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 548, + 545, + 592 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 548, + 545, + 592 + ], + "spans": [ + { + "bbox": [ + 308, + 548, + 545, + 592 + ], + "type": "text", + "content": "[16] Lei Ke, Yu-Wing Tai, and Chi-Keung Tang. Deep occlusion-aware instance segmentation with overlapping bilayers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4019–4028, 2021." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 593, + 547, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 593, + 547, + 635 + ], + "spans": [ + { + "bbox": [ + 308, + 593, + 547, + 635 + ], + "type": "text", + "content": "[17] Youngwan Lee and Jongyoul Park. CenterMask: Realtime anchor-free instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13906-13915, 2020." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 636, + 545, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 636, + 545, + 679 + ], + "spans": [ + { + "bbox": [ + 308, + 636, + 545, + 679 + ], + "type": "text", + "content": "[18] Ke Li, Bharath Hariharan, and Jitendra Malik. Iterative instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3659-3667, 2016." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 681, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 681, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 681, + 545, + 713 + ], + "type": "text", + "content": "[19] Ke Li and Jitendra Malik. Amodal instance segmentation. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 677-693, 2016." + } + ] + } + ], + "index": 25 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "text", + "content": "23512" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 127 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 127 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 127 + ], + "type": "text", + "content": "[20] Zhixuan Li, Ruohua Shi, Tiejun Huang, and Tingting Jiang. OAFormer: Learning occlusion distinguishable feature for amodal instance segmentation. In International Conference on Acoustics, Speech, and Signal Processing, pages 1-5, 2023." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 130, + 287, + 174 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 130, + 287, + 174 + ], + "spans": [ + { + "bbox": [ + 48, + 130, + 287, + 174 + ], + "type": "text", + "content": "[21] Zhixuan Li, Weining Ye, Tingting Jiang, and Tiejun Huang. 2D amodal instance segmentation guided by 3D shape prior. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 165-181, 2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 176, + 287, + 210 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 176, + 287, + 210 + ], + "spans": [ + { + "bbox": [ + 48, + 176, + 287, + 210 + ], + "type": "text", + "content": "[22] Zhixuan Li, Weining Ye, Tingting Jiang, and Tiejun Huang. GIN: Generative invariant shape prior for amodal instance segmentation. In IEEE Transactions on Multimedia, 2023." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 212, + 287, + 266 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 212, + 287, + 266 + ], + "spans": [ + { + "bbox": [ + 48, + 212, + 287, + 266 + ], + "type": "text", + "content": "[23] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dálár, and C Lawrence Zitnick. Microsoft COCO: Common objects in context. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 740-755, 2014." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 268, + 287, + 312 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 268, + 287, + 312 + ], + "spans": [ + { + "bbox": [ + 48, + 268, + 287, + 312 + ], + "type": "text", + "content": "[24] Huan Ling, David Acuna, Karsten Kreis, Seung Wook Kim, and Sanja Fidler. Variational amodal object completion. In Advances in Neural Information Processing Systems, pages 16246-16257, 2020." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 314, + 287, + 369 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 314, + 287, + 369 + ], + "spans": [ + { + "bbox": [ + 48, + 314, + 287, + 369 + ], + "type": "text", + "content": "[25] D. Martin, C. Fowlkes, D. Tal, and J. Malik. A database of human segmented natural images and its application to evaluating segmentation algorithms and measuring ecological statistics. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 416-423, 2001." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 371, + 287, + 415 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 371, + 287, + 415 + ], + "spans": [ + { + "bbox": [ + 48, + 371, + 287, + 415 + ], + "type": "text", + "content": "[26] Sida Peng, Wen Jiang, Huaijin Pi, Xiuli Li, Hujun Bao, and Xiaowei Zhou. Deep snake for real-time instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 417, + 287, + 460 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 417, + 287, + 460 + ], + "spans": [ + { + "bbox": [ + 48, + 417, + 287, + 460 + ], + "type": "text", + "content": "[27] Lu Qi, Li Jiang, Shu Liu, Xiaoyong Shen, and Jiaya Jia. Amodal instance segmentation with KINS dataset. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3014-3023, 2019." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 463, + 287, + 518 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 463, + 287, + 518 + ], + "spans": [ + { + "bbox": [ + 48, + 463, + 287, + 518 + ], + "type": "text", + "content": "[28] Mennatullah Siam, Sara Elkerdawy, Martin Jagersand, and Senthil Yogamani. Deep semantic segmentation for automated driving: Taxonomy, roadmap and challenges. In IEEE International Conference on Intelligent Transportation Systems, pages 1-8, 2017." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 520, + 287, + 564 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 520, + 287, + 564 + ], + "spans": [ + { + "bbox": [ + 48, + 520, + 287, + 564 + ], + "type": "text", + "content": "[29] Xiaolin Song, Kaili Zhao, Wen-Sheng Chu, Honggang Zhang, and Jun Guo. Progressive refinement network for occluded pedestrian detection. In Proceedings of the IEEE/CVF European Conference on Computer Vision, 2020." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 567, + 287, + 609 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 567, + 287, + 609 + ], + "spans": [ + { + "bbox": [ + 48, + 567, + 287, + 609 + ], + "type": "text", + "content": "[30] Zhi Tian, Chunhua Shen, and Hao Chen. Conditional convolutions for instance segmentation. In Proceedings of the IEEE/CVF European Conference on Computer Vision, pages 282-298, 2020." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 612, + 287, + 667 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 612, + 287, + 667 + ], + "spans": [ + { + "bbox": [ + 48, + 612, + 287, + 667 + ], + "type": "text", + "content": "[31] Gül Varol, Javier Romero, Xavier Martin, Naureen Mahmood, Michael Black, Ivan Laptev, and Cordelia Schmid. Learning from synthetic humans. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4627-4635, 2017." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "type": "text", + "content": "[32] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Advances in Neural Information Processing Systems, pages 5998-6008, 2017." + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 72, + 547, + 475 + ], + "type": "list", + "angle": 0, + "index": 22, + "blocks": [ + { + "bbox": [ + 307, + 72, + 547, + 127 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 72, + 547, + 127 + ], + "spans": [ + { + "bbox": [ + 307, + 72, + 547, + 127 + ], + "type": "text", + "content": "[33] Yuting Xiao, Yanyu Xu, Ziming Zhong, Weixin Luo, Jiawei Li, and Shenghua Gao. Amodal segmentation based on visible region segmentation and shape prior. In Proceedings of the AAAI Conference on Artificial Intelligence, pages 2995-3003, 2021." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 129, + 547, + 183 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 129, + 547, + 183 + ], + "spans": [ + { + "bbox": [ + 307, + 129, + 547, + 183 + ], + "type": "text", + "content": "[34] Jin Xie, Yanwei Pang, M. H. Khan, Rao Muhammad Anwer, Fahad Shahbaz Khan, and Ling Shao. Mask-guided attention network and occlusion-sensitive hard example mining for occluded pedestrian detection. IEEE Transactions on Image Processing, 30:3872-3884, 2021." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 185, + 547, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 185, + 547, + 239 + ], + "spans": [ + { + "bbox": [ + 307, + 185, + 547, + 239 + ], + "type": "text", + "content": "[35] Xiaohang Zhan, Xingang Pan, Bo Dai, Ziwei Liu, Dahua Lin, and Chen Change Loy. Self-supervised scene de- occlusion. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 3784- 3792, 2020." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 240, + 547, + 284 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 240, + 547, + 284 + ], + "spans": [ + { + "bbox": [ + 307, + 240, + 547, + 284 + ], + "type": "text", + "content": "[36] Shifeng Zhang, Longyin Wen, Xiao Bian, Zhen Lei, and S. Li. Occlusion-aware R-CNN: Detecting pedestrians in a crowd. In Proceedings of the IEEE/CVF European Conference on Computer Vision, 2018." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 285, + 547, + 339 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 285, + 547, + 339 + ], + "spans": [ + { + "bbox": [ + 307, + 285, + 547, + 339 + ], + "type": "text", + "content": "[37] Tao Zhang, Shiqing Wei, and Shunping Ji. E2EC: An end-to-end contour-based method for high-quality high-speed instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4443-4452, 2022." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 341, + 547, + 396 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 341, + 547, + 396 + ], + "spans": [ + { + "bbox": [ + 307, + 341, + 547, + 396 + ], + "type": "text", + "content": "[38] Ziheng Zhang, Anpei Chen, Ling Xie, Jingyi Yu, and Shenghua Gao. Learning semantics-aware distance map with semantics layering network for amodal instance segmentation. In Proceedings of the ACM International Conference on Multimedia, pages 2124-2132, 2019." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 397, + 547, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 397, + 547, + 430 + ], + "spans": [ + { + "bbox": [ + 307, + 397, + 547, + 430 + ], + "type": "text", + "content": "[39] Kaiyang Zhou, Yongxin Yang, Yu Qiao, and Tao Xiang. Domain generalization with mixstyle. In International Conference on Learning Representations, 2021." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 431, + 547, + 475 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 431, + 547, + 475 + ], + "spans": [ + { + "bbox": [ + 307, + 431, + 547, + 475 + ], + "type": "text", + "content": "[40] Yan Zhu, Yuandong Tian, Dimitris Metaxas, and Piotr Dólar. Semantic amodal segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1464-1472, 2017." + } + ] + } + ], + "index": 21 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "text", + "content": "23513" + } + ] + } + ], + "index": 23 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MUter_ Machine Unlearning on Adversarially Trained Models/794014c8-e2b9-40ef-b0f6-0010a00c9a4d_content_list.json b/2023/MUter_ Machine Unlearning on Adversarially Trained Models/794014c8-e2b9-40ef-b0f6-0010a00c9a4d_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..863ad3410b108c97bf4bb2337eb66ad841a0a72c --- /dev/null +++ b/2023/MUter_ Machine Unlearning on Adversarially Trained Models/794014c8-e2b9-40ef-b0f6-0010a00c9a4d_content_list.json @@ -0,0 +1,2087 @@ +[ + { + "type": "text", + "text": "MUt er: Machine Unlearning on Adversarily Trained Models", + "text_level": 1, + "bbox": [ + 188, + 181, + 781, + 201 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Junxu Liu $^{1,*}$ , Mingsheng Xue $^{2,*}$ , Jian Lou $^{3,6,\\dagger}$ , Xiaoyu Zhang $^{4}$ , Li Xiong $^{5}$ , Zhan Qin $^{3,6}$", + "bbox": [ + 184, + 225, + 781, + 241 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1Renmin University of China 2Guangzhou Institute of Technology, Xidian University 3Zhejiang University 4Xidian University 5Emory University 6ZJU-Hangzhou Global Scientific and Technological Innovation Center", + "bbox": [ + 141, + 241, + 828, + 271 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "junxu_liu@ruc.edu.cn xuemingsheng@stu.xidian.edu.cn jian.lou@zju.edu.cn", + "bbox": [ + 181, + 273, + 789, + 286 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "xiaoyuzhang@xidian.edu.cn lxiong@emory.edu qinzhan@zju.edu.cn", + "bbox": [ + 221, + 289, + 747, + 301 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 250, + 331, + 322, + 344 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Machine unlearning is an emerging task of removing the influence of selected training datapoints from a trained model upon data deletion requests, which echoes the widely enforced data regulations mandating the Right to be Forgotten. Many unlearning methods have been proposed recently, achieving significant efficiency gains over the naive baseline of retraining from scratch. However, existing methods focus exclusively on unlearning from standard training models and do not apply to adversarial training models (ATMs) despite their popularity as effective defenses against adversarial examples. During adversarial training, the training data are involved in not only an outer loop for minimizing the training loss, but also an inner loop for generating the adversarial perturbation. Such bi-level optimization greatly complicates the influence measure for the data to be deleted and renders the unlearning more challenging than standard model training with single-level optimization. This paper proposes a new approach called MUt er for unlearning from ATMs. We derive a closed-form unlearning step underpinned by a total Hessian-related data influence measure, while existing methods can mis-capture the data influence associated with the indirect Hessian part. We further alleviate the computational cost by introducing a series of approximations and conversions to avoid the most computationally demanding parts of Hessian inversions. The efficiency and effectiveness of MUt er have been validated through experiments on four datasets using both linear and neural network models.", + "bbox": [ + 100, + 359, + 473, + 709 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 102, + 736, + 226, + 750 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Machine learning (ML) models are increasingly applied to a broad range of applications, accompanied by growing concerns about their privacy and robustness issues. Both issues are actively studied in recent years [45]. On the", + "bbox": [ + 100, + 758, + 470, + 811 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "privacy side, model inversion attack [16] and membership inference attack [51] reveal that the trained ML model contains sensitive information of its training data, which can cause privacy loss for individuals contributing their data for model training. On the robustness side, adversarial example attack is one of the most well-recognized robustness attacks [24, 30, 39, 62]. It can easily fool an undefended model, e.g., standard training model (STM), to misclassify by a small adversarial perturbation on the input [9, 24, 39]. Many works focus either on the privacy [1, 35, 37, 42, 51] or on the robustness aspect [9, 33, 38, 53–56, 66], few works studied both. Yet, it is critical to consider privacy and robustness jointly [20, 27, 36, 41, 47, 48, 52] to build ML models to simultaneously meet data privacy regulations and ensure robustness against adversarial threats.", + "bbox": [ + 499, + 332, + 870, + 527 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In this paper, we target a new joint privacy-robustness problem to simultaneously meet emerging privacy regulations and ensure adversarial robustness of the model, which has not been examined before: how to efficiently and effectively remove the influence of a training datapoint from an adversarially trained model upon data deletion request?", + "bbox": [ + 497, + 529, + 868, + 606 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The privacy need is driven by the widely enacted user data regulations that enforce the Right to be Forgotten, for example, the European Union's GDPR [17], the California Consumer Privacy Act (CCPA), and Canada's proposed Consumer Privacy Protection Act (CPPA). These regulations mandate the deletion of personal data upon user requests and can even include the deletion of models and algorithms derived from the user data, e.g., the Federal Trade Commission [15]. Machine unlearning [5,8] aims to obtain an updated model with the influence of the target datapoint removed in an effective and efficient way. That is, the updated model should be similar to the model obtained by the computationally expensive retraining-from-scratch approach, while consuming less computation [21-23,26,31,43,44,58,60,61,65].", + "bbox": [ + 497, + 608, + 870, + 790 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The robustness is achieved by the adversarial training model (ATM) [3, 24, 30, 39, 59], which is a popular and effective defense for enhancing the model robustness against adversarial examples by creating and incorporating adver", + "bbox": [ + 497, + 792, + 870, + 844 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 95, + 8, + 171, + 46 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 231, + 5, + 815, + 48 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Equal contribution.", + "bbox": [ + 119, + 821, + 223, + 832 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "† Corresponding Author.", + "bbox": [ + 122, + 832, + 240, + 843 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "4892", + "bbox": [ + 468, + 875, + 500, + 885 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/6a501db60794b36cfe20ab0dcdd885488c378fbbfc9395fcfe13273a8ad874fc.jpg", + "image_caption": [ + "Figure 1: ATM has two interdependent sets of optimization variables, model parameters and adversarial perturbations (yellow arrows), both of which contain nested training data influence (blue arrows). To remove such nested data influence, ATM unlearning requires the total Hessian that consists of both direct and indirect Hessian components (green solid lines). Existing unlearning methods designed for standard training models are inapplicable to ATM unlearning, because they only use direct Hessian information during the unlearning update and do not capture sufficient data influence (red dashed lines)." + ], + "image_footnote": [], + "bbox": [ + 142, + 147, + 831, + 313 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "sarial examples into the training process. ATM is trained by a bi-level optimization with the model parameters as the outer-level variable and the adversarial perturbations as the inner-level variable. To the best of our knowledge, all existing unlearning methods focus solely on data removal from STM. As our analysis will reveal in Section 3, the existing methods cannot be applied to ATM unlearning without miscapturing the data influence to be removed, due to ATM's bi-level optimization structure.", + "bbox": [ + 100, + 410, + 473, + 527 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this paper, we propose a new unlearning approach called MUt e r: M Machine Unlearning for data removal from adversarial training models. First, we define the ATM unlearning task in accordance with the mainstream machine unlearning standard. Second, we convert it to an ATM unlearning criteria derived from the optimality condition of ATM, which facilitates the derivation of the unlearning update for ATM. Meanwhile, existing unlearning methods designed for STM cannot satisfy the ATM unlearning criteria. As illustrated in Figure 1, ATM, as a bi-level optimization, has two sets of variables: model parameters and adversarial perturbations, which are interdependent and both contain training data information. In contrast, STM, as a single-level optimization, has only one set of variables: model parameters, which have a direct influence dependence on each training datapoint. Existing unlearning methods cannot sufficiently remove data influence from ATM because they fail to account for the indirect influence on the model parameters (i.e., miss the indirect Hessian part in Figure 1). That is, due to the coupled outer-inner optimization, any updates to the outer model parameters will incur further updates for both the adversarial perturbations and the model parameters. To address this, we derive a new closed-form unlearning update for ATM, which is underpinned by the total Hessian-based", + "bbox": [ + 100, + 532, + 473, + 845 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "influence measure. Third, based on the ATM unlearning update, we propose a three-stage unlearning framework to support successive unlearning requests for ATM, which enhances efficiency by selectively storing certain computations in memory. Last, we leverage Schur complement conversion and Neumann series approximation to avoid the computationally demanding and numerical unstable computations of Hessian matrix and its inversions.", + "bbox": [ + 497, + 410, + 870, + 513 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To summarize, our main contributions are:", + "bbox": [ + 517, + 515, + 784, + 526 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1. We introduce the problem of unlearning from adversarial training models, which is a new and pressing challenge to simultaneously meet emerging privacy regulations and ensure the adversarial robustness of the model. To the best of our knowledge, it has not been studied in the existing literature.", + "2. We derive a new unlearning update tailored to ATM unlearning, which has the total Hessian-based data influence measure to sufficiently account for the interdependence between inner and outer optimizations of ATM.", + "3. We propose MUt er based on the proposed unlearning update, which supports successive unlearning requests for ATM and introduces a series of conversions and approximations for Hessian inversions to alleviate the computational cost and improve the numerical stability.", + "4. We perform a comprehensive evaluation to verify that $MUter$ achieves effective and efficient unlearning performance while maintaining the model accuracy and adversarial robustness, under two unlearning settings on four datasets." + ], + "bbox": [ + 497, + 527, + 870, + 761 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Preliminaries and Related Work", + "text_level": 1, + "bbox": [ + 499, + 771, + 778, + 786 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Setup and Notation", + "text_level": 1, + "bbox": [ + 499, + 794, + 675, + 809 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Setup. Denote the training dataset with $n$ training samples by $\\mathcal{D} = \\{(\\mathbf{x}_1,y_1),\\ldots ,(\\mathbf{x}_n,y_n)\\}$ , where for $\\forall i\\in$", + "bbox": [ + 497, + 817, + 870, + 845 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "4893", + "bbox": [ + 468, + 876, + 500, + 885 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "$\\{1,\\dots ,n\\}$ $\\mathbf{x}_i\\in \\mathbb{R}^d$ is the $d$ -dimensional feature vector, and $y_{i}\\in \\mathbb{R}$ is the corresponding response/label. Denote the loss function by $l(\\omega ,\\mathbf{x}_i)$ , where $\\omega \\in \\mathbb{R}^p$ represents the vector of the $p$ -dimensional model parameters.", + "bbox": [ + 100, + 147, + 470, + 201 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Standard Training Model (STM). Standard training model refers to the empirical risk minimization model: $\\omega_{std}^{*} = \\mathrm{argmin}_{\\omega}\\frac{1}{n}\\sum_{i = 1}^{n}l(\\omega ,\\mathbf{x}_i)$ , where $\\omega \\in \\mathbb{R}^p$ is the model parameter variable.", + "bbox": [ + 100, + 204, + 472, + 256 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Adversarial Training Model (ATM). Adversarial training model is an effective defense against robustness threats posed by the adversarial attack. In this paper, we adopt one of the most widely-used ATM variants to consider the following bi-level robust optimization formulation [30, 50],", + "bbox": [ + 100, + 258, + 472, + 321 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {\\omega} ^ {*} = \\underset {\\boldsymbol {\\omega}} {\\operatorname {a r g m i n}} \\frac {1}{n} \\sum_ {i = 1} ^ {n} \\max _ {\\delta_ {i} \\in \\mathcal {B} (\\mathbf {x} _ {i}, r)} l (\\boldsymbol {\\omega}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i}), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 152, + 330, + 472, + 359 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where the inner optimization is to find adversarial perturbation $\\delta_{i}$ from the constraint set $\\mathcal{B}(\\mathbf{x}_i,r)$ to maximize the loss and the outer optimization is to find the model parameter $\\omega$ that minimizes the loss for the adversarially perturbed examples. To make the interdependence between the outer variable $\\omega$ and the inner variable $\\delta$ more explicit, we further introduce an auxiliary function $\\delta_{i}(\\omega)$ given by", + "bbox": [ + 100, + 369, + 472, + 454 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\delta_ {i} (\\boldsymbol {\\omega}) = \\underset {\\boldsymbol {\\delta} _ {i} \\in \\mathcal {B} (\\mathbf {x} _ {i}, r)} {\\operatorname {a r g m a x}} l \\left(\\boldsymbol {\\omega}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i}\\right). \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 186, + 463, + 472, + 485 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Machine Unlearning for Adversarial Training Models. Definition 1 below specifies the ATM unlearning task in consistency with the mainstream unlearning standard. For notational simplicity, we focus on single-point removal in the paper, but the analysis and algorithms developed in the paper are generalizable to batch removal as well (please refer to Appendix B.5 for the batch removal generalization).", + "bbox": [ + 100, + 497, + 472, + 590 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Definition 1. (Machine Unlearning for Adversarial Training Models) For a trained adversarial training model as in eq.(1), let $\\forall i^{\\dagger}\\in \\{1,\\dots ,n\\}$ be the index of a datapoint to be forgotten. The ATM after machine unlearning unlearning (forgetting datapoint $i^{\\dagger}$ ) has parameter $\\omega_{-i^{\\dagger}}^{*}$ as follows,", + "bbox": [ + 100, + 598, + 472, + 660 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\omega_ {- i ^ {\\dagger}} ^ {*} = \\underset {\\omega} {\\operatorname {a r g m i n}} \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\max _ {\\delta_ {i} \\in \\mathcal {B} (\\mathbf {x} _ {i}, r)} l (\\omega , \\mathbf {x} _ {i} + \\delta_ {i}). \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 115, + 671, + 472, + 701 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Retraining-from-scratch serves as the golden standard and also a naive baseline to obtain the unlearned ATM $\\omega_{-i\\dagger}^{*}$ , which is prohibitive in computation, especially for ATM with both inner maximization and outer minimization. Hence, the goal of machine unlearning for ATM is to approximately remove $i^{\\dagger}$ 's influence with great computational efficiency improvement over retraining-from-scratch.", + "bbox": [ + 100, + 712, + 472, + 804 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Notation. For a twice differentiable $l(\\omega, \\mathbf{x} + \\delta)$ , $\\nabla_{\\omega} l(\\omega, \\mathbf{x} + \\delta)$ denotes the direct gradient of $l$ with respect to (w.r.t.) $\\omega$ and $\\partial_{\\omega \\omega} l(\\omega, \\mathbf{x} + \\delta)$ , $\\partial_{\\omega \\delta} l(\\omega, \\mathbf{x} + \\delta)$ , $\\partial_{\\delta \\omega} l(\\omega, \\mathbf{x} + \\delta)$ ,", + "bbox": [ + 100, + 806, + 472, + 845 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "$\\partial_{\\delta \\delta}l(\\omega ,\\mathbf{x} + \\delta)$ denote the second order partial derivatives w.r.t. $\\omega$ and $\\delta$ , correspondingly. The total Hessian is", + "bbox": [ + 497, + 148, + 867, + 173 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {D} _ {\\omega \\omega} l (\\omega , \\mathbf {x} + \\delta) := \\overbrace {\\partial_ {\\omega \\omega} l (\\omega , \\mathbf {x} + \\delta)} ^ {\\text {D i r e c t H e s s i a n}} - \\overbrace {\\partial_ {\\omega \\delta} \\partial_ {\\delta \\delta} ^ {- 1} \\partial_ {\\delta \\omega} l (\\omega , \\mathbf {x} + \\delta)} ^ {\\text {I n d i r e c t H e s s i a n}}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 499, + 182, + 867, + 222 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\partial_{\\omega \\delta}\\partial_{\\delta \\delta}^{-1}\\partial_{\\delta \\omega}l(\\omega ,\\mathbf{x} + \\boldsymbol {\\delta}) = \\partial_{\\omega \\delta}l(\\omega ,\\mathbf{x} + \\boldsymbol {\\delta})(\\partial_{\\delta \\delta}l(\\omega ,\\mathbf{x} + \\boldsymbol {\\delta}))^{-1}\\partial_{\\delta \\omega}l(\\omega ,\\mathbf{x} + \\boldsymbol {\\delta})$ .We also use the short hand notation $l_i^*\\coloneqq l(\\pmb {\\omega}^*,\\mathbf{x}_i + \\delta_i(\\pmb {\\omega}^*))$ and similarly introduce $\\nabla_{\\omega}l_{i}^{*},\\partial_{\\omega \\omega}l_{i}^{*},\\partial_{\\omega \\delta}l_{i}^{*},\\partial_{\\delta \\omega}l_{i}^{*},\\partial_{\\delta \\delta}l_{i}^{*}$", + "bbox": [ + 497, + 222, + 868, + 276 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 283, + 633, + 296 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We briefly review existing machine unlearning methods. They are exclusively focused on STM and are not applicable to ATM unlearning with sufficient data influence removal. We provide a brief overview of current machine unlearning methods, which are focused exclusively on unlearning for STM and are not applicable to ATM unlearning with sufficient data influence removal. Thus, it is necessary to develop a new unlearning approach specific to ATM unlearning.", + "bbox": [ + 497, + 304, + 868, + 409 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Exact Machine Unlearning. Exact unlearning methods perform exact retraining but manage to do so only on a selective portion of the dataset to avoid retraining on the entire dataset. Some exact unlearning methods are designed for specific models like Naive Bayes [8], quantized k-means [19], and random forests [6]. Recently, SISA [5] proposes a more general exact unlearning strategy. It divides the training data into multiple disjoint shards during the training phase, and retransmits only on the shard that contains the data to be removed during the unlearning phase. Later, [11] and [12] extend the SISA strategy to unlearning for recommendation systems and graph neural networks. However, the SISA strategy requires different shards to be independently updatable from each other, which is not the case for ATM due to its interdependent bi-level structure.", + "bbox": [ + 497, + 410, + 868, + 606 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Approximate Machine Unlearning. Approximate unlearning methods seek the updated model parameters to approximately satisfy the optimality condition of the objective function on the remaining data, which can be roughly divided into three categories. 1) Unlearning with direct Hessian-related terms: [22, 26, 31, 34, 40, 43, 49] propose Newton step-based unlearning updates, where the Newton curvature matrices are direct Hessian-related terms. These methods also inject Gaussian noise to further destroy the remaining data influence due to the discrepancy between the exact unlearning standard and the approximate unlearning criteria. Some works also consider to alleviate the computational cost of the Hessian. For example, [22] proposes to approximate the direct Hessian with Fisher information matrix; [43] proposes to avoid dealing with the entire direct Hessian by selecting small Hessian blocks for unlearning update. 2) Unlearning based on neural tangent kernel (NTK) theory: they approximates the training phase by NTK theory, where [23] regards", + "bbox": [ + 497, + 610, + 868, + 845 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "4894", + "bbox": [ + 468, + 876, + 500, + 885 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "the training as an approximately linear change and [21] divides the training phase into two stages, one is the linear standard training on the core dataset, and the other is the linear finetuning on the target dataset. Both works then apply direct Hessian-related unlearning updates. 3) Unlearning by tracking the Stochastic Gradient Descent (SGD) path during training: DeltaGrad [60] and unrollSGD [57] propose to track and reverse the SGD optimization path during the training phase. However, all above methods do not consider the interdependence between model parameters and adversarial perturbations of ATM, which cannot holistically capture the data influence, as will be detailed in the next section.", + "bbox": [ + 100, + 148, + 473, + 305 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3. Unlearning Update for ATM", + "text_level": 1, + "bbox": [ + 102, + 314, + 349, + 328 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "ATM Unlearning Criteria. We begin by converting eq.(3) in Definition 1 to the optimality condition form of ATM based on Danskin's Theorem [13],", + "bbox": [ + 100, + 338, + 472, + 378 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\nabla_ {\\omega} l \\left(\\omega_ {- i ^ {\\dagger}} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\omega_ {- i ^ {\\dagger}} ^ {*}\\right)\\right) = 0, \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 159, + 383, + 472, + 419 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "which provides more convenience to the follow-up ATM unlearning designs. Our goal is to find a closed-form unlearning update $\\mathcal{U}(\\boldsymbol{\\omega}^*, i^\\dagger)$ such that the unlearning model with parameter $\\boldsymbol{\\omega}^u = \\boldsymbol{\\omega}^* + \\mathcal{U}(\\boldsymbol{\\omega}^*, i^\\dagger)$ will satisfy the following ATM unlearning criteria,", + "bbox": [ + 100, + 423, + 473, + 491 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\nabla_ {\\omega} l \\left(\\omega^ {u}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\omega^ {u}\\right)\\right) \\approx 0. \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 171, + 495, + 472, + 532 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Cause of Inapplicability of Existing Approximate Unlearning Methods. Before deriving our ATM unlearning update, we recall the design rationale common to existing approximate machine unlearning methods and point out why they fail to sufficiently remove the data influence for ATM. Despite the varying forms of specific unlearning updates, existing approximate unlearning methods all exploit the trained model parameter $\\omega^{*}$ and connect it with the unlearned model $\\omega^{u}$ by first-order expansion of $\\nabla_{\\omega}l$ around $\\omega^{*}$ :", + "bbox": [ + 100, + 536, + 473, + 649 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\nabla_ {\\omega} l \\left(\\omega^ {u}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\omega^ {u}\\right)\\right) \\\\ \\approx \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\left[ \\nabla_ {\\omega} l \\left(\\omega^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\omega^ {u}\\right)\\right) \\right. \\tag {7} \\\\ \\left. + \\partial_ {\\omega} \\omega l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {u}\\right)\\right) \\left(\\boldsymbol {\\omega} ^ {u} - \\boldsymbol {\\omega} ^ {*}\\right) \\right]. \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 163, + 654, + 472, + 739 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Existing methods then obtain the updated $\\omega^u$ by letting the right hand side of eq.(7) approach 0 and exploiting the optimality condition of $\\omega^{*}$ . For example, the influence function-inspired unlearning [26, 49] has $\\mathbf{u}(\\boldsymbol{\\omega}^{*}, i^{\\dagger}) =$", + "bbox": [ + 100, + 742, + 473, + 792 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\left[ \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\underbrace {\\partial_ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {u}\\right)\\right)} _ {\\text {D i r e c t H e s s i a n - o n l y}} \\right] ^ {- 1} \\nabla_ {\\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\delta_ {i ^ {\\dagger}} \\left(\\boldsymbol {\\omega} ^ {u}\\right)\\right). \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 105, + 796, + 472, + 844 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "However, there are two obvious issues when applying the above design rationale to the ATM unlearning: 1) the conversion from eq.(7) to eq.(8) requires $\\sum_{i=1}^{n} \\nabla_{\\omega} l(\\omega^{*}, \\mathbf{x}_{i} + \\delta_{i}(\\omega^{u})) = 0$ , which does not hold in general. Rather, the optimality condition only promises $\\sum_{i=1}^{n} \\nabla_{\\omega} l(\\omega^{*}, \\mathbf{x}_{i} + \\delta_{i}(\\omega^{*})) = 0$ ; 2) the Hessian $\\partial_{\\omega \\omega} l(\\omega^{*}, \\mathbf{x}_{i} + \\delta_{i}(\\omega^{u}))$ and gradient $\\nabla_{\\omega} l(\\omega^{*}, \\mathbf{x}_{i} + \\delta_{i}(\\omega^{u}))$ in eq.(8) are not commutable without knowing $\\omega^{u}$ in advance. We point out that the root cause of both issues is that eq.(7) fails to account for the interdependence between $\\omega$ and $\\delta$ as in eq.(2).", + "bbox": [ + 497, + 148, + 870, + 277 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Proposed ATM Unlearning Update. The above root cause propels us to derive a new unlearning update that can holistically capture the nested data influence. To account for the interdependence between the adversarial perturbations and the model parameters in eq.(2), we take the complete expansion w.r.t. both $\\omega$ and $\\delta$ as in Lemma 1 below.", + "bbox": [ + 497, + 281, + 870, + 359 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Lemma 1. By expansion around both $\\omega^{*}$ and $\\delta (\\omega^{*})$ , the approximate machine unlearning model parameter $\\omega^u$ and the original model parameter $\\omega^{*}$ has the following relation,", + "bbox": [ + 497, + 366, + 870, + 407 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\nabla_ {\\boldsymbol {\\omega}} l (\\boldsymbol {\\omega} ^ {u}, \\mathbf {x} _ {i} + \\delta_ {i} (\\boldsymbol {\\omega} ^ {u})) \\\\ \\approx \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\left[ \\nabla_ {\\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {*}\\right)\\right) \\right. \\tag {9} \\\\ + \\partial_ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {*}\\right)\\right) \\left(\\boldsymbol {\\omega} ^ {u} - \\boldsymbol {\\omega} ^ {*}\\right) \\\\ \\left. + \\partial_ {\\boldsymbol {\\omega} \\delta} l (\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} (\\boldsymbol {\\omega} ^ {*})) (\\delta_ {i} (\\boldsymbol {\\omega} ^ {u}) - \\delta_ {i} (\\boldsymbol {\\omega} ^ {*})) \\right]. \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 517, + 414, + 868, + 530 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Proof. Please refer to Appendix B.1.", + "bbox": [ + 499, + 536, + 731, + 549 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/abb4a22bf9055ecd5bb11fdbd33969e720f11b20a9d7d7d195b6294f72c87c1c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 852, + 538, + 868, + 547 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The last line of eq.(9) is key to the sufficient removal of the data influence from ATM, which captures the interdependence between the adversarial perturbations and the model parameters. Based on Lemma 1, we can derive the ATM unlearning update in closed-form in Theorem 1 below.", + "bbox": [ + 497, + 558, + 870, + 624 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Theorem 1. Consider the adversarial training model with trained model parameter $\\omega^{*}$ as in eq.(1). Let $(\\mathbf{x}_{i^{\\dagger}},y_{i^{\\dagger}})$ be a datapoint in the training dataset to be forgotten. Let the machine learning update $\\mathcal{U}(\\boldsymbol {\\omega}^*,i^{\\dagger})$ take the following form", + "bbox": [ + 497, + 629, + 870, + 680 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {U} \\left(\\boldsymbol {\\omega} ^ {*}, i ^ {\\dagger}\\right) := \\left[ \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\underbrace {\\mathrm {D} _ {\\boldsymbol {\\omega} \\boldsymbol {\\omega}} l \\left(\\boldsymbol {\\omega} ^ {*} , \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {*}\\right)\\right)} _ {\\text {T o t a l H e s s i a n}} \\right] ^ {- 1} \\tag {10} \\\\ \\cdot \\left[ \\nabla_ {\\boldsymbol {\\omega}} l (\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\delta_ {i ^ {\\dagger}} (\\boldsymbol {\\omega} ^ {*})) \\right]. \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 524, + 686, + 868, + 744 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Then, the unlearning model with updated parameters $\\omega^u \\coloneqq \\omega^* + \\mathcal{U}(\\omega^*, i^\\dagger)$ satisfies the approximate unlearning criteria for the adversarial training model in eq.(6).", + "bbox": [ + 497, + 749, + 870, + 790 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Proof. Please refer to Appendix B.1.", + "bbox": [ + 499, + 796, + 732, + 809 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "It turns out that the ATM unlearning in eq.(10) requires both direct Hessian and indirect Hessian (i.e., total Hessian", + "bbox": [ + 497, + 817, + 870, + 844 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "4895", + "bbox": [ + 468, + 876, + 500, + 885 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "in eq.(4)) to sufficiently capture the data influence, while previous methods for the STM unlearning have only the direct Hessian-related part (e.g., eq.(8)). The total Hessian term also appears in the second-order bi-level optimization literature, e.g., the Complete Newton method in [64].", + "bbox": [ + 100, + 148, + 472, + 214 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "A New Influence Function. Finally, we would like to remark that eq.(10) can be used to define a new influence function as follows to measure the nested data influence of a data point for ATM. It could serve as an independent interest, for example, to measure the marginal contribution of a data point to the model for valuation in data market [46] and influence-based defense against data poisoning attacks [18].", + "bbox": [ + 100, + 218, + 473, + 309 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Definition 2. (Leave-one-out Adversarial Influence Function) For the adversarial training model given in eq.(1), the leave-one-out adversarial influence function for any $(\\mathbf{x},y)$ in the training dataset is defined as", + "bbox": [ + 100, + 320, + 472, + 368 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {I} (\\mathbf {x}, y) = - \\left[ \\frac {1}{n} \\sum_ {i = 1} ^ {n} \\mathrm {D} _ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i} ^ {*}\\right) \\right] ^ {- 1} \\nabla_ {\\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} + \\boldsymbol {\\delta} ^ {*}\\right).\n$$\n", + "text_format": "latex", + "bbox": [ + 105, + 378, + 465, + 409 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Definition 2 utilizes total Hessian instead of direct Hessian-only as in [32], which captures the interdependence between adversarial perturbations and model parameters. This is different from recent work [14] which defines the adversarial influence function as a training sample's influence difference between two models: an STM and an ATM, while Definition 2 measures a training sample's influence difference when it is in or out for a single ATM.", + "bbox": [ + 100, + 421, + 473, + 524 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Proposed Method: MUt er", + "text_level": 1, + "bbox": [ + 100, + 540, + 327, + 554 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Equipped with the ATM unlearning update, we propose MUt er, a three-stage unlearning method for ATM, which has two design considerations: 1) Support the more practical successive unlearning setting where multiple data points can be forgotten in sequence by keeping a selective variable set in memory (Sec.4.1); 2) Reduce the per-unlearning computational cost by introducing more efficient approximations and conversions to avoid direct computations of the most computational demanding Hessian inversions (Sec.4.2). The overall framework of MUt er is illustrated in Figure 2. We also present the complete algorithm in Appendix B.4.", + "bbox": [ + 100, + 562, + 470, + 706 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Three Stages of MUt er", + "text_level": 1, + "bbox": [ + 100, + 716, + 294, + 730 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Successive Unlearning Setting. Denote the indices of datapoints that have already been forgotten at timestamp $r$ by $\\{i_1^\\dagger, \\ldots, i_r^\\dagger\\}$ , the index of datapoint to be forgotten at timestamp $r + 1$ by $i_{r + 1}^\\dagger = i^\\dagger$ . Corollary 1 below extends Theorem 1 to support successive unlearning for ATM.", + "bbox": [ + 100, + 741, + 472, + 809 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Corollary 1. Considering the successive unlearning setting, let the machine unlearning update at the $r + 1$ -th timestamp", + "bbox": [ + 100, + 819, + 472, + 844 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "$\\mathfrak{U}_r(\\omega^*, i_{r+1}^\\dagger)$ take the following form", + "bbox": [ + 499, + 147, + 734, + 162 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {U} _ {r} \\left(\\boldsymbol {\\omega} ^ {*}, i _ {r + 1} ^ {\\dagger}\\right) := \\left\\{\\overbrace {\\left[ \\sum_ {i = 1} ^ {n} \\mathrm {D} _ {\\boldsymbol {\\omega} \\boldsymbol {\\omega}} l \\left(\\boldsymbol {\\omega} ^ {*} , \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i} ^ {*}\\right) \\right]} ^ {\\mathcal {M} _ {0} [ \\mathrm {D} _ {\\boldsymbol {\\omega} \\boldsymbol {\\omega}} ]} - \\right.\n$$\n", + "text_format": "latex", + "bbox": [ + 507, + 172, + 786, + 219 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\overbrace {\\left[ \\sum_ {i = i _ {1} ^ {\\dagger}} ^ {i _ {r} ^ {\\dagger}} \\mathrm {D} _ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i} ^ {*}\\right) \\right] - \\left[ \\mathrm {D} _ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i \\dagger} + \\boldsymbol {\\delta} _ {i \\dagger} ^ {*}\\right) \\right]} ^ {\\text {P a r t o f} \\mathcal {M} _ {r} [ \\mathrm {D} _ {\\omega \\omega} ]} ^ {- 1} \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 510, + 222, + 868, + 277 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\cdot \\overbrace {\\left[ \\sum_ {i = i _ {1} ^ {\\dagger}} ^ {i _ {r} ^ {\\dagger}} \\nabla_ {\\omega} l (\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i} ^ {*}) + \\nabla_ {\\omega} l (\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\boldsymbol {\\delta} _ {i ^ {\\dagger}} ^ {*}) \\right]} ^ {\\mathcal {M} _ {r} [ \\nabla_ {\\boldsymbol {\\omega}} ]}.\n$$\n", + "text_format": "latex", + "bbox": [ + 512, + 281, + 801, + 337 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Then, the unlearning model with updated parameters $\\omega_{r + 1}^{u}\\coloneqq \\omega^{*} + \\mathbf{U}_{r}(\\boldsymbol{\\omega}^{*},i_{r + 1}^{\\dagger})$ satisfies the approximate unlearning criteria for the adversarial training model in eq.(6).", + "bbox": [ + 499, + 347, + 870, + 385 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Proof. Please refer to Appendix B.2.", + "bbox": [ + 499, + 396, + 731, + 410 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Stage I. Pre-Unlearning. According to Corollary 1, it is a natural idea to pre-compute and keep in memory the total Hessian $\\left[\\sum_{i=1}^{n} \\mathsf{D}_{\\omega \\omega} l(\\boldsymbol{\\omega}^*, \\mathbf{x}_i + \\boldsymbol{\\delta}_i^*)\\right]$ once the ATM is trained and before responding to unlearning requests, since it does not depend on the new point to be removed. Thus, we initialize a memory set $\\mathcal{M}_0$ at $r = 0$ , which has three memory parts: $\\mathcal{M}_0[\\mathsf{D}_{\\omega \\omega}]$ for $\\left[\\sum_{i=1}^{n} \\mathsf{D}_{\\omega \\omega} l(\\boldsymbol{\\omega}^*, \\mathbf{x}_i + \\boldsymbol{\\delta}_i^*)\\right]$ , $\\mathcal{M}_0[\\boldsymbol{\\omega}^*]$ for $\\boldsymbol{\\omega}^*$ , and $\\mathcal{M}_0[\\nabla_{\\boldsymbol{\\omega}}]$ for $\\nabla_{\\boldsymbol{\\omega}} = \\mathbf{0}$ at $r = 0$ .", + "bbox": [ + 497, + 425, + 870, + 542 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Stage II. Unlearning. Upon receiving a new unlearning request to forget the $i^{\\dagger}$ -th datapoint at timestamp $r + 1$ , Corollary 1 indicates that it suffices to compute the total Hessian and gradient only on $i^{\\dagger}$ rather than the entire training set, once the memory is set up and maintained. We evaluate the following three parts in sequence: 1) The gradient on $i^{\\dagger} \\colon \\nabla_{\\omega} l(\\boldsymbol{\\omega}^{*}, \\mathbf{x}_{i^{\\dagger}} + \\boldsymbol{\\delta}_{i^{\\dagger}}^{*})$ ; 2) The total Hessian on $i^{\\dagger} \\colon \\mathrm{D}_{\\omega} \\omega l(\\boldsymbol{\\omega}^{*}, \\mathbf{x}_{i^{\\dagger}} + \\boldsymbol{\\delta}_{i^{\\dagger}}^{*})$ ; 3) The unlearning update $\\mathcal{U}_r(\\boldsymbol{\\omega}^*, i_{r+1}^{\\dagger})$ in eq.(11) and the updated parameters $\\boldsymbol{\\omega}_{r+1}^u$ . In addition, we can also inject Gaussian noise by $\\boldsymbol{\\omega}_{r+1}^u + \\mathbf{n}$ with $\\mathbf{n} \\sim \\mathcal{N}(0, \\sigma^2 \\mathbf{I})$ to further smooth the remaining data influence to the discrepancy between eq.(3) and eq.(6).", + "bbox": [ + 497, + 545, + 868, + 705 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Stage III. Post-Unlearning. To support subsequent unlearning requests, we update $\\mathcal{M}_{r + 1}$ based on Corollary 1:", + "bbox": [ + 499, + 707, + 868, + 733 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {M} _ {r + 1} \\left[ \\mathrm {D} _ {\\omega \\omega} \\right] = \\mathcal {M} _ {r} \\left[ \\mathrm {D} _ {\\omega \\omega} \\right] - \\mathrm {D} _ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\boldsymbol {\\delta} _ {i ^ {\\dagger}} ^ {*}\\right); \\tag {12}\n$$\n", + "text_format": "latex", + "bbox": [ + 514, + 744, + 868, + 760 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {M} _ {r + 1} [ \\nabla_ {\\omega} ] = \\mathcal {M} _ {r} [ \\nabla_ {\\omega} ] + \\nabla_ {\\omega} l \\left(\\omega^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\boldsymbol {\\delta} _ {i ^ {\\dagger}} ^ {*}\\right), \\tag {13}\n$$\n", + "text_format": "latex", + "bbox": [ + 521, + 761, + 868, + 776 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where the former is the online update for $\\left[\\sum_{i=1}^{n} \\mathrm{D}_{\\omega \\omega} l\\left(\\omega^{*}, \\mathbf{x}_{i} + \\boldsymbol{\\delta}_{i}^{*}\\right)\\right] - \\left[\\sum_{i=i_{1}^{\\dagger}}^{i_{1}^{\\dagger} + 1} \\mathrm{D}_{\\omega \\omega} l\\left(\\omega^{*}, \\mathbf{x}_{i} + \\boldsymbol{\\delta}_{i}^{*}\\right)\\right]$", + "bbox": [ + 499, + 787, + 867, + 823 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "and the latter is for $\\left[\\sum_{i = i_1}^{i_{r + 1}}\\nabla_{\\omega}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_i + \\boldsymbol{\\delta}_i^*)\\right]$ .", + "bbox": [ + 499, + 823, + 801, + 847 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "4896", + "bbox": [ + 468, + 876, + 500, + 885 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/f7186078cbb0413cac9155c9148967f6acfcd1491e6ca859ea8c76c3eaa3dce0.jpg", + "image_caption": [ + "Figure 2: The proposed MUt er framework. Stage I: the pre-unlearning stage prepares the initial memory $\\mathcal{M}_0[\\mathbb{D}_{\\omega \\omega}],\\mathcal{M}_0[\\nabla_{\\omega}],\\mathcal{M}_0[\\omega^* ]$ . Stage II: the unlearning stage computes the total Hessian and gradient on the data to be forgotten and computes the ATM unlearning update by solving a linear system. Stage II: the post-unlearning stage updates $\\mathcal{M}_{r + 1}[\\mathbb{D}_{\\omega \\omega}]$ and $\\mathcal{M}_{r + 1}[\\nabla_{\\omega}]$ to be prepared for the next unlearning request." + ], + "image_footnote": [], + "bbox": [ + 124, + 146, + 845, + 271 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Unlearning without Direct Hessian Inversions", + "text_level": 1, + "bbox": [ + 100, + 353, + 465, + 369 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We now present the approximations and conversions to circumvent the most computationally expensive and potentially numerical unstable parts in the three stages, which are three Hessian matrix inversions: (Inv-1) The total Hessian inversion of $\\left[\\mathcal{M}_r[\\mathrm{D}_{\\omega \\omega}] - \\mathrm{D}_{\\omega \\omega}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_{i^\\dagger} + \\boldsymbol{\\delta}_{i^\\dagger}^*)\\right]^{-1}$ ; (Inv-2) The partial Hessian inversion of $\\partial_{\\delta \\delta}^{-1}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_{i^\\dagger} + \\boldsymbol{\\delta}_{i^\\dagger}^*)$ inside the total Hessian in Stage II; (Inv-3) The same $\\partial_{\\delta \\delta}^{-1}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_{i^\\dagger} + \\boldsymbol{\\delta}_{i^\\dagger}^*)$ but in Stage I & III.", + "bbox": [ + 100, + 375, + 473, + 483 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Avoid Matrix Inversions (Inv-1/2) jointly by Schur Complement Conversion. After expanding the total Hessian as in eq.(4), we can reorganize $\\left[\\mathcal{M}_r[\\mathbb{D}_{\\omega \\omega}] - \\mathbb{D}_{\\omega \\omega}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_{i^\\dagger} + \\delta_{i^\\dagger}^*)\\right]$ into the following form $\\mathbf{S} = \\left[\\mathcal{M}_r[\\mathbb{D}_{\\omega \\omega}] - \\partial_{\\omega \\omega}l_{i^\\dagger}^*\\right] - \\left[-\\partial_{\\omega \\delta}\\partial_{\\delta \\delta}^{-1}\\partial_{\\delta \\omega}l_{i^\\dagger}^*\\right]$ , which can be regarded as the Schur complement of the block matrix $\\mathbf{H}$ :", + "bbox": [ + 100, + 486, + 473, + 579 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {H} = \\left[ \\begin{array}{l l} \\mathbf {H} _ {1 1} & \\mathbf {H} _ {1 2} \\\\ \\mathbf {H} _ {2 1} & \\mathbf {H} _ {2 2} \\end{array} \\right] = \\left[ \\begin{array}{c c} \\mathcal {M} _ {r} [ \\mathrm {D} _ {\\omega \\omega} ] - \\partial_ {\\omega \\omega} l _ {i ^ {\\dagger}} ^ {*} & \\partial_ {\\omega \\delta} l _ {i ^ {\\dagger}} ^ {*} \\\\ \\partial_ {\\delta \\omega} l _ {i ^ {\\dagger}} ^ {*} & - \\partial_ {\\delta \\delta} l _ {i ^ {\\dagger}} ^ {*} \\end{array} \\right]. \\tag {14}\n$$\n", + "text_format": "latex", + "bbox": [ + 107, + 587, + 470, + 629 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "By Schur complement lemma, we can find the inversion of $\\mathbf{S}$ to the inversion of $\\mathbf{H}$ , then the unlearning update is equivalent to solving a linear system, as summarized in the following Theorem.", + "bbox": [ + 100, + 638, + 470, + 692 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Theorem 2. The unlearning update $\\mathfrak{U}_r(\\omega^*, i_{r+1}^\\dagger)$ in eq.(11) can be equivalently computed by solving the linear system:", + "bbox": [ + 100, + 700, + 470, + 726 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\left[ \\begin{array}{c c} \\mathcal {M} _ {r} [ \\mathrm {D} _ {\\omega \\omega} ] - \\partial_ {\\omega \\omega} l _ {i ^ {\\dagger}} ^ {*} & \\partial_ {\\omega \\mathbf {x}} l _ {i ^ {\\dagger}} ^ {*} \\\\ \\partial_ {\\mathbf {x} \\omega} l _ {i ^ {\\dagger}} ^ {*} & - \\partial_ {\\mathbf {x x}} l _ {i ^ {\\dagger}} ^ {*} \\end{array} \\right] \\left[ \\begin{array}{c} \\Delta \\boldsymbol {\\omega} \\\\ \\Delta \\boldsymbol {\\alpha} \\end{array} \\right] = \\left[ \\begin{array}{c} \\mathcal {M} _ {r} [ \\nabla \\omega ] + \\nabla_ {\\omega} l _ {i ^ {\\dagger}} ^ {*} \\\\ \\mathbf {0} \\end{array} \\right],\n$$\n", + "text_format": "latex", + "bbox": [ + 105, + 733, + 485, + 761 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $\\Delta \\omega$ is the unlearning update $\\mathcal{U}_r(\\omega^*, i_{r+1}^\\dagger)$ and $\\Delta \\alpha$ is an auxiliary variable that can be discarded.", + "bbox": [ + 102, + 769, + 470, + 796 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The linear system in Theorem 2 can be solved by conjugate gradient or fixed point methods, which are more efficient than computing the Hessian inversions (Inv-1/2) directly.", + "bbox": [ + 100, + 804, + 472, + 844 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Avoid Matrix Inversions (Inv-3) by Neumann Series Approximation. We expand $\\partial_{\\delta \\delta}^{-1}l_i^*$ by Neumann Series: $\\partial_{\\delta \\delta}^{-1}l_i^* = \\lim_{k\\to \\infty}\\sum_{j = 0}^{k}\\left[\\mathbf{I} - \\partial_{\\mathbf{xx}}l_i^*\\right]^j$ . Then, clipping at order $k$ , we have the following approximation,", + "bbox": [ + 497, + 353, + 868, + 410 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\partial_ {\\delta \\delta} ^ {- 1} l _ {i} ^ {*} \\approx \\mathbf {I} + \\left[ \\mathbf {I} - \\partial_ {\\delta \\delta} l _ {i} ^ {*} \\right] + \\dots + \\left[ \\mathbf {I} - \\partial_ {\\delta \\delta} l _ {i} ^ {*} \\right] ^ {k}. \\tag {15}\n$$\n", + "text_format": "latex", + "bbox": [ + 519, + 418, + 868, + 437 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Each term in memory $\\mathcal{M}_r[\\mathrm{D}_{\\omega \\omega}]$ used in Stage I & III can be approximated by $\\mathrm{D}_{\\omega \\omega}l_i^* \\approx \\overline{\\mathrm{D}}_{\\omega \\omega}l_i^* :=$", + "bbox": [ + 497, + 442, + 867, + 471 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\partial_ {\\omega \\omega} l _ {i} ^ {*} - \\partial_ {\\omega \\delta} l _ {i} ^ {*} \\left(\\sum_ {j = 0} ^ {k} \\left[ \\mathbf {I} - \\partial_ {\\delta \\delta} l _ {i} ^ {*} \\right] ^ {j}\\right) \\partial_ {\\delta \\omega} l _ {i} ^ {*}. \\tag {16}\n$$\n", + "text_format": "latex", + "bbox": [ + 549, + 478, + 868, + 514 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 499, + 522, + 623, + 536 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We conduct experimental evaluations on two groups of machine learning models and four common datasets, under two typical experiment settings in the unlearning literature [21-23, 26]. Our source code, experiment details, and more experiment results can be found in Supplement.", + "bbox": [ + 497, + 543, + 868, + 610 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Experiment Setup", + "text_level": 1, + "bbox": [ + 499, + 616, + 665, + 630 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1.1 Models and Datasets", + "text_level": 1, + "bbox": [ + 499, + 636, + 685, + 648 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Linear Models. We consider two linear models: 1) Ridge Regression (RR) with least square loss; 2) Logistic Regression (LR) with logistic loss, both are regularized by squared $\\ell_2$ -norm with hyperparameter $\\lambda = 1e - 4$ .", + "bbox": [ + 497, + 659, + 868, + 712 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Neural Network Models. We utilize the Wide ResNet model (i.e., Wide ResNet 28-10 model) [63] and consider the pretraining setting [22, 26] (also similar to the mixed-privacy removal setting [21]) for the neural network model as follows. We first pretrain a model on a core dataset with adversarial training. We then finetune the model on another target dataset with adversarial finetuning [28], where all layers are frozen except the last layer. We consider unlearning requests from only the target dataset used for the adversarial finetuning.", + "bbox": [ + 497, + 713, + 868, + 844 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "4897", + "bbox": [ + 468, + 875, + 500, + 885 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Adversarial Training/Finetuning Algorithms. For outer-level, we utilize SGD to optimize the model parameters $\\omega^{*}$ ; for inner-level, we utilize both PGD [39] and FGSM [24] to generate adversarial perturbations. The experiment results by PGD are reported in the paper, while the results by FGSM and more detailed training and finetuning settings are relegated to Appendix A.1 and A.3.", + "bbox": [ + 100, + 148, + 473, + 239 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Datasets. We consider four common datasets for the two settings above: (linear models) i) MNIST- $\\mathbf{b}$ is the subset from MNIST with classes '1' and '7' for binary classification purpose; ii) Covtype is a dataset from the LIBSVM repository [10]; (neural network model with pretraining) iii) CIFAR-10 (target dataset) and the Downsampled ImageNet (core dataset) are both natural image datasets; iv) Lacuna-10 (target dataset) and Lacuna-100 (core dataset) are both face datasets. More detail can be found in Appendix A.2.", + "bbox": [ + 100, + 243, + 473, + 361 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.1.2 Baseline Unlearning Methods", + "text_level": 1, + "bbox": [ + 102, + 377, + 346, + 391 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We compare MUt er with six approximate unlearning methods (with their abbreviations in bold), all of which are originally designed for unlearning from standard training models. Since they utilize different Hessian terms in the unlearning update, for a fair comparison, we evaluate them under the same three-stage framework as MUt er but substitute in their corresponding unlearning update formulations. (1) Newton unlearning [26] and (2) Newton unlearning measured with adversarial perturbation (Newton-delta): both methods utilize the Newton step as the unlearning update, where the former computes at the original samples (i.e., $\\left[\\sum_{i = 1,i\\neq i\\dagger}^{n}\\partial_{\\omega \\omega}l(\\boldsymbol{\\omega}^{*},\\mathbf{x}_{i})\\right]^{-1}\\nabla_{\\omega}l(\\boldsymbol{\\omega}^{*},\\mathbf{x}_{i\\dagger})$ and the latter at the adversarially perturbed samples (i.e., $\\left[\\sum_{i = 1,i\\neq i\\dagger}^{n}\\partial_{\\omega \\omega}l(\\boldsymbol{\\omega}^{*},\\mathbf{x}_{i} + \\boldsymbol{\\delta}_{i}^{*})\\right]^{-1}\\nabla_{\\omega}l(\\boldsymbol{\\omega}^{*},\\mathbf{x}_{i\\dagger} + \\boldsymbol{\\delta}_{i\\dagger}^{*})$ ). Similarly, we have (3) Fisher unlearning [22] and (4) Fisher-delta, which utilize the Fisher matrix $(\\nabla_{\\omega}l\\cdot \\nabla_{\\omega}^{\\top}l)$ to approximate the direct Hessian $\\partial_{\\omega \\omega}l$ . (5) Influence function-based unlearning [32, 40] and (6) Influence-delta, which utilize the influence function for STM for the unlearning update.", + "bbox": [ + 100, + 397, + 473, + 649 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Meanwhile, we utilize (7) Retrain-from-scratch as the golden standard reference, which applies the same adversarial training/finetuning algorithms to retrain/re-finetune the model on the remaining data to obtain $\\omega_{-i\\dagger}^{*}$ in eq.(3).", + "bbox": [ + 100, + 649, + 473, + 703 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.1.3 Evaluation Metrics", + "text_level": 1, + "bbox": [ + 102, + 718, + 280, + 731 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We measure four aspects of the unlearning performance: 1) Effectiveness measures the closeness of the unlearned ATM compared to the golden standard Retrain, for which we utilize the $\\ell_2$ -norm difference between the model parameter vectors, i.e., $\\| \\boldsymbol{\\omega}^u - \\boldsymbol{\\omega}_{-i^\\dagger}^*\\|_2$ ; 2) Accuracy measures the clean accuracy of the unlearned ATM, for which we utilize the accuracy on clean test samples; 3) Robustness measures the adversarial accuracy of the unlearned ATM, for which we", + "bbox": [ + 100, + 739, + 473, + 844 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/4afe7bbf0ba6b56c8523ef5d19617b8520776a4229d1c6cd31795b8e4ec439e9.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 544, + 148, + 847, + 166 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/35c6e74f40f345acdceba95852e24680e1b867577f3afac37d3a4878759a95b2.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 515, + 174, + 680, + 286 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/9bc1066fe0a1f511b909a0cb64ffccef84ff021afe13f0e67968316982485dfb.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 687, + 173, + 855, + 286 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/4382d88274c5ed09a758410e7ce0f5f61cb6ece613f9531cf56ca4f735fc644c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 517, + 302, + 684, + 408 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/12d3b37e9d690e749d929c53e69791414955c90c0b539ae2d60891327bca19ec.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 687, + 302, + 855, + 408 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/80a7067843a62b970e9103df3197b39178d2750d33b0d1c3edfe511a450c19ca.jpg", + "image_caption": [ + "Figure 3: Evaluation results on Logistic Regression Model: Effectiveness (top), Accuracy (middle), and Robustness (bottom) on datasets MNIST-b (left column), Covtype (right column). Large plots have greater removal numbers: $1\\%$ , $2\\%$ , $\\cdots$ , $5\\%$ ; the inside small plots have fewer removal numbers: $1,2,\\cdots,5$ ." + ], + "image_footnote": [], + "bbox": [ + 515, + 422, + 678, + 530 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/754bc211380f4d6c78d872df2248456c4ccb19ef2630c0da505970a3cd0b55b1.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 685, + 423, + 855, + 530 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "utilize the accuracy on adversarial perturbed test samples; 4) Efficiency measures the unlearning time the unlearning method takes to respond the unlearning request, for which we report CPU time.", + "bbox": [ + 497, + 654, + 870, + 707 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.2. Experiment Results", + "text_level": 1, + "bbox": [ + 499, + 717, + 677, + 731 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.2.1 Results with Linear Model", + "text_level": 1, + "bbox": [ + 499, + 738, + 724, + 751 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Figure 3 reports the experiment results with logistic regression model on the MNIST-b and Covtypes datasets. More results with ridge regression are deferred to Appendix A.3.", + "bbox": [ + 497, + 761, + 870, + 800 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Effectiveness. Top row of Figure 3 shows the effectiveness comparison. All compared methods have increased model parameter distance with the increasing number of unlearning", + "bbox": [ + 497, + 804, + 870, + 845 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "4898", + "bbox": [ + 468, + 876, + 500, + 885 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/a73fdcc799b61851c5bf67004c89ee7faba69f0430875a5920da4cfaf0419553.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 117, + 150, + 290, + 268 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/83ba5f1b25738a31a57e20f15cad1bb753270bfdbe402b6182adca821842378a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 295, + 152, + 460, + 269 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/5e5d26435969fe46870b32b04bbe8957efb787ab6ad4d45938350c6dadca044e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 112, + 270, + 290, + 385 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/a81c2e680793d79c43a011598a0e0b37139e7d3bf307a330a0770ea4eb30f4ec.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 290, + 271, + 460, + 385 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/3f87baacd32401b9f056d0598dcde1102b78044f81e0add1831d7aaa73887589.jpg", + "image_caption": [ + "Figure 4: Evaluation results on Neural Network: Effectiveness (top), Accuracy (middle), and Robustness (bottom) on datasets Lacuna-10 (left column) and CIFAR-10 (right column), under removal numbers $(1,0.4\\%, 1\\%, 2\\%, 4\\%, 8\\%)$ ." + ], + "image_footnote": [], + "bbox": [ + 110, + 387, + 289, + 502 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/15861c24a1c405179ae16bb1a768abcbe8bbf5c9f3cdc673914115f8d39da6e3.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 289, + 393, + 460, + 502 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/dd78cf12c80061f42aaae032e89511cb4cdd35d05c5c4af68f0cf7dc4cce7501.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Model TypeRemoval NumberMNIST-bCovtype
FisherF-deltaMIterRetrainFisherF-deltaMIterRetrain
LR10.0020.0020.009630.0020.0020.007192
50.0100.0120.052630.0090.0110.037194
100.0190.0210.106620.0180.0220.071194
RR10.0020.0020.009640.0020.0020.006200
50.0090.0110.057650.0110.0120.032206
100.0180.0190.097650.0190.0200.064205
", + "bbox": [ + 107, + 584, + 470, + 662 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "requests, which is due to the decreased approximation capability of the approximate unlearning criteria. MUter achieves the smallest deviation from Retrain and outperforms all the compared methods, which is because its ATM unlearning update sufficiently captures the nested data influence in ATM.", + "bbox": [ + 100, + 747, + 470, + 813 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Accuracy. Middle row of Figure 3 shows the clean accuracy comparison. All unlearning methods do not show a signifi", + "bbox": [ + 100, + 817, + 472, + 844 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/a19eab8f374592a356b973b1eb9038e032ad9017eb8241fa367335ab712ea8ce.jpg", + "table_caption": [ + "Table 1: Efficiency results with linear models of logistic regression (top) and ridge regression (bottom): The unlearning time (in seconds) of Fisher, Fisher-delta, MUt er and Retrain under varying removal numbers: 1, 5, 10." + ], + "table_footnote": [], + "table_body": "
Removal NumberLacuna-10CIFAR-10
FisherF-deltaMUtErRetrainFisherF-deltaMUtErRetrain
11.471.664.189351.511.733.815224
57.768.4121.379347.548.5818.645294
1015.5116.8241.6993215.3416.4237.575260
", + "bbox": [ + 505, + 146, + 868, + 201 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 2: Efficiency results with Neural Network: The unlearning time (in seconds) of Fisher, Fisher-delta, MUt er and Retrain under varying removal numbers: 1, 5, 10.", + "bbox": [ + 497, + 211, + 870, + 250 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "cant drop in clean accuracy after data forgotten. In general, $MUtEr$ is among the methods that achieve higher accuracy and exhibits close consistency with Retrain.", + "bbox": [ + 497, + 274, + 868, + 313 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Robustness. Bottom row of Figure 3 shows the robustness comparison. When the number of forgotten requests is small, most methods have little variation in perturbed accuracy. When the forgotten number becomes larger, all baseline unlearning methods have an obvious decrease in perturbed accuracy, while MUt er still shows high perturbed accuracy and has the closest proximity to Retrain.", + "bbox": [ + 497, + 315, + 868, + 408 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Efficiency. Table 1 shows the efficiency comparison. MUt er has significant efficiency improvement over Retrain, which is the utmost desideratum of the unlearning method. In addition, we compare with Fisher and Fisher-delta, which are the most efficient methods among the six baseline methods due to the more efficient Fisher information matrix approximation. MUt er takes more CPU time because it computes the total Hessian to obtain a more holistic data influence measure, while the baseline methods compute only the (approximate) direct Hessian and omit the indirect Hessian. Thus, the small increase in CPU time is the necessary tax to pay in exchange for more effective unlearning.", + "bbox": [ + 497, + 410, + 868, + 568 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Tradeoff between deletion effectiveness, accuracy, and robustness. According to the above results, there is a tradeoff between efficient and deletion effectiveness, accuracy, and robustness. That is, $MUtEr$ takes slightly longer than direct Hessian-only unlearning methods due to the additional computation of the indirect Hessian. However, this extra computation is worthwhile as $MUtEr$ offers improved deletion effectiveness, accuracy, and robustness.", + "bbox": [ + 497, + 571, + 868, + 675 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.2.2 Results with Neural Network Model", + "text_level": 1, + "bbox": [ + 499, + 693, + 786, + 705 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Figure 4 summarizes the results of effectiveness, accuracy, and robustness on the two datasets for the neural network model with pretraining. MUt er has the smallest difference of parameter distance with Retrain, which indicates that MUt er generates the most similar unlearning model to the Retrain model. In addition, MUt er has the most consistent behaviour with Retrain in terms of clean accuracy and perturbation accuracy. In terms of efficiency, Table 2 reports the comparison with Retrain and two most efficient baseline methods Fisher and Fisher-delta. Similar to the linear", + "bbox": [ + 497, + 714, + 868, + 843 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "4899", + "bbox": [ + 468, + 876, + 500, + 885 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/25a2f5f6f29b3319475d2a42d728ad31266fce976a66d471de7e54bb1a024fe5.jpg", + "image_caption": [ + "Figure 5: Effect of Gaussian noise injection: Effectiveness (left), Accuracy (middle), and Robustness (right) versus the standard variation $\\sigma$ of Gaussian noise in log scale, under the case of removing $5\\%$ samples and on the Lacuna-10 dataset." + ], + "image_footnote": [], + "bbox": [ + 206, + 149, + 384, + 255 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/77d03821b289f247a743d56bf2ade4c7706f59c4674980356d35b3c5414a8ae3.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 396, + 150, + 574, + 255 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/ae00c2840e6e62d9da79df0ee15f1fb7eba876aecf2c9775abe499e6d22dd95c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 586, + 150, + 766, + 255 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "model case, MUt er has significant efficiency improvement over Retrain. Although MUt er costs more unlearning time than the approximate methods, it provides significantly more effective, more accurate, and more robust unlearned ATM.", + "bbox": [ + 100, + 318, + 470, + 371 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Effect of Varying Magnitudes of Gaussian Noise. Figure 5 shows the effectiveness, accuracy, and robustness comparisons under varying standard variations of Gaussian noise $(\\sigma)$ injected by $\\omega_{r + 1}^u +\\mathbf{n}$ with $\\mathbf{n}\\sim \\mathcal{N}(0,\\sigma^2\\mathbf{I})$ . All methods get worse unlearning model performance with larger $\\sigma$ , but MUt er maintains the best performance for all $\\sigma$ ’s among all compared unlearning methods.", + "bbox": [ + 100, + 374, + 473, + 465 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 102, + 477, + 215, + 491 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this paper, we studied a new joint privacy-robustness problem of machine unlearning from adversarial training models to simultaneously meet the emerging privacy regulations on Right to be Forgotten and ensure the adversarial robustness of the model. We proposed a new unlearning method called Muter, which is underpinned by a total Hessian-based measure to sufficiently capture the data influence on both model parameters and adversarial perturbations. We further introduced the Schur complement conversion and the Neumann series approximation to mitigate the computational cost. Our methods show significant enhancement in effectiveness and efficiency compared to baseline methods.", + "bbox": [ + 100, + 498, + 473, + 654 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "As future works, several directions can be further explored: 1) extending $MUter$ to other adversarial training variants like adversarial regularization; 2) further reducing the memory cost by considering low-rank/k-fact approximations to approximate the Hessian matrix, e.g., [25]; 3) studying the approximation capability of the new influence function inspired by $MUter$ , e.g., across different depths of neural networks [4]; 4) exploring the potential connection between the new influence function with proximal Bregman response function [2].", + "bbox": [ + 100, + 654, + 470, + 785 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "7. Acknowledgement", + "text_level": 1, + "bbox": [ + 102, + 796, + 272, + 809 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "The authors would like to thank the anonymous reviewers for their constructive comments. This research has been", + "bbox": [ + 100, + 817, + 470, + 844 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "funded in part by National Science Foundation of China (NSFC) 62206207, 62102300, 62072395, and U20A20178, National Key Research and Development Program of China 2020AAA0107705, National Science Foundation (NSF) CNS-2124104, CNS-2125530, and National Institute of Health (NIH) R01ES033241.", + "bbox": [ + 497, + 318, + 870, + 397 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 500, + 415, + 589, + 429 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Martin Abadi, Andy Chu, Ian Goodfellow, H Brendan McMahan, Ilya Mironov, Kunal Talwar, and Li Zhang. Deep learning with differential privacy. In Proceedings of the 2016 ACM SIGSAC conference on computer and communications security, 2016. 1", + "[2] Juhan Bae, Nathan Ng, Alston Lo, Marzyeh Ghassemi, and Roger B. Grosse. If influence functions are the answer, then what is the question? In NeurIPS, 2022. 9", + "[3] Tao Bai, Jinqi Luo, Jun Zhao, Bihan Wen, and Qian Wang. Recent advances in adversarial training for adversarial robustness. In Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence, pages 4312-4321, 8 2021. Survey Track. 1", + "[4] Samyadeep Basu, Phillip Pope, and Soheil Feizi. Influence functions in deep learning are fragile. In 9th International Conference on Learning Representations, ICLR 2021, Virtual Event, Austria, May 3-7, 2021, 2021. 9", + "[5] Lucas Bourtoule, Varun Chandrasekaran, Christopher A. Choquette-Choo, Hengrui Jia, Adelin Travers, Baiwu Zhang, David Lie, and Nicolas Papernot. Machine unlearning. In 42nd IEEE Symposium on Security and Privacy, 2021. 1, 3", + "[6] Jonathan Brophy and Daniel Lowd. Machine unlearning for random forests. In International Conference on Machine Learning, pages 1092-1104, 2021. 3", + "[7] Qiong Cao, Li Shen, Weidi Xie, Omkar M. Parkhi, and Andrew Zisserman. Vggface2: A dataset for recognising faces across pose and age. In 2018 13th IEEE International Conference on Automatic Face Gesture Recognition (FG 2018), pages 67-74, 2018. 12", + "[8] Yinzhi Cao and Junfeng Yang. Towards making systems forget with machine unlearning. In 2015 IEEE Symposium on Security and Privacy, pages 463-480. IEEE, 2015. 1, 3" + ], + "bbox": [ + 507, + 439, + 870, + 844 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "4900", + "bbox": [ + 468, + 876, + 500, + 885 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[9] Nicholas Carlini and David Wagner. Towards evaluating the robustness of neural networks. In 2017 IEEE Symposium on Security and Privacy. IEEE Computer Society, 2017. 1", + "[10] Chih-Chung Chang and Chih-Jen Lin. Libsvm: A library for support vector machines. ACM Trans. Intell. Syst. Technol., 2(3), may 2011. 7", + "[11] Chong Chen, Fei Sun, Min Zhang, and Bolin Ding. Recommendation unlearning. In Proceedings of the ACM Web Conference 2022, pages 2768-2777, 2022. 3", + "[12] Min Chen, Zhikun Zhang, Tianhao Wang, Michael Backes, Mathias Humbert, and Yang Zhang. Graph unlearning. In Proceedings of the ACM Conference on Computer and Communications Security 2022, 2022. 3", + "[13] John M Danskin. The theory of max-min and its application to weapons allocation problems, volume 5. Springer Science & Business Media, 2012. 4", + "[14] Zhun Deng, Cynthia Dwork, Jialiang Wang, and Linjun Zhang. Interpreting robust optimization via adversarial influence functions. In Proceedings of the 37th International Conference on Machine Learning, volume 119, 2020. 5", + "[15] Federal Trade Commission. California company settles ftc allegations it deceived consumers about use of facial recognition in photo storage app, January 2021. 1", + "[16] Matt Fredrikson, Somesh Jha, and Thomas Ristenpart. Model inversion attacks that exploit confidence information and basic countermeasures. In Proceedings of the 22nd ACM SIGSAC conference on computer and communications security, pages 1322-1333, 2015. 1", + "[17] Regulation (EU) 2016/679 of the European parliament and of the council of 27 April 2016, 2016. 1", + "[18] Amirata Ghorbani and James Zou. Data shapley: Equitable valuation of data for machine learning. In International Conference on Machine Learning, pages 2242-2251, 2019. 5", + "[19] Antonio A Ginart, Melody Y Guan, Gregory Valiant, and James Zou. Making ai forget you: data deletion in machine learning. In Proceedings of the 33rd International Conference on Neural Information Processing Systems, 2019. 3", + "[20] Jairo Giraldo, Alvaro Cardenas, Murat Kantarcioglu, and Jonathan Katz. Adversarial classification under differential privacy. In Network and Distributed Systems Security (NDSS) Symposium 2020, 2020. 1", + "[21] Aditya Golatkar, Alessandro Achille, Avinash Ravichandran, Marzia Polito, and Stefano Soatto. Mixed-privacy forgetting in deep networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 792–801, 2021. 1, 4, 6", + "[22] Aditya Golatkar, Alessandro Achille, and Stefano Soatto. Eternal sunshine of the spotless net: Selective forgetting in deep networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9304-9312, 2020. 1, 3, 6, 7, 12", + "[23] Aditya Golatkar, Alessandro Achille, and Stefano Soatto. Forgetting outside the box: Scrubbing deep networks of information accessible from input-output observations. In European Conference on Computer Vision, 2020. 1, 3, 6", + "[24] Ian J. Goodfellow, Jonathon Shlens, and Christian Szegedy. Explaining and harnessing adversarial examples. In Yoshua" + ], + "bbox": [ + 104, + 149, + 470, + 843 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Bengio and Yann LeCun, editors, 3rd International Conference on Learning Representations, 2015. 1, 7", + "[25] Roger Grosse, Juhan Bae, Cem Anil, Nelson Elhage, Alex Tamkin, Amirhossein Tajdini, Benoit Steiner, Dustin Li, Esin Durmus, Ethan Perez, et al. Studying large language model generalization with influence functions. arXiv preprint arXiv:2308.03296, 2023. 9", + "[26] Chuan Guo, Tom Goldstein, Awni Y. Hannun, and Laurens van der Maaten. Certified data removal from machine learning models. In Proceedings of the 37th International Conference on Machine Learning, 2020. 1, 3, 4, 6, 7", + "[27] Jamie Hayes, Borja Balle, and M Pawan Kumar. Learning to be adversarially robust and differentially private. arXiv preprint arXiv:2201.02265, 2022. 1", + "[28] Dan Hendrycks, Kimin Lee, and Mantas Mazeika. Using pre-training can improve model robustness and uncertainty. In Kamalika Chaudhuri and Ruslan Salakhutdinov, editors, Proceedings of the 36th International Conference on Machine Learning, volume 97 of Proceedings of Machine Learning Research, pages 2712-2721, 09-15 Jun 2019. 6", + "[29] Dan Hendrycks, Kimin Lee, and Mantas Mazeika. Using pre-training can improve model robustness and uncertainty. In International Conference on Machine Learning, pages 2712-2721, 2019. 12", + "[30] Ruitong Huang, Bing Xu, Dale Schuurmans, and Csaba Szepesvári. Learning with a strong adversary. CoRR, abs/1511.03034, 2015. 1, 3", + "[31] Zachary Izzo, Mary Anne Smart, Kamalika Chaudhuri, and James Zou. Approximate data deletion from machine learning models. In International Conference on Artificial Intelligence and Statistics, pages 2008-2016, 2021. 1, 3", + "[32] Pang Wei Koh and Percy Liang. Understanding black-box predictions via influence functions. In International Conference on Machine Learning, 2017. 5, 7, 12", + "[33] Haowen Lin, Jian Lou, Li Xiong, and Cyrus Shahabi. Integer-arithmetic-only certified robustness for quantized neural networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7828-7837, 2021. 1", + "[34] Shen Lin, Xiaoyu Zhang, Chenyang Chen, Xiaofeng Chen, and Willy Susilo. Erm-ktp: Knowledge-level machine unlearning via knowledge transfer. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2023. 3", + "[35] Junxu Liu, Jian Lou, Li Xiong, Jinfei Liu, and Xiaofeng Meng. Projected federated averaging with heterogeneous differential privacy. Proceedings of the VLDB Endowment, 15(4):828-840, 2021. 1", + "[36] Yang Liu, Mingyuan Fan, Cen Chen, Ximeng Liu, Zhuo Ma, Li Wang, and Jianfeng Ma. Backdoor defense with machine unlearning. In IEEE INFOCOM 2022 - IEEE Conference on Computer Communications, page 280-289, 2022. 1", + "[37] Jian Lou and Yiu-ming Cheung. An uplink communication-efficient approach to featurewise distributed sparse optimization with differential privacy. IEEE Transactions on Neural Networks and Learning Systems, 32(10):4529-4543, 2020. 1", + "[38] Jie Ma, Xiangyuan Lan, Bineng Zhong, Guorong Li, Zhenjun Tang, Xianxian Li, and Rongrong Ji. Robust tracking via" + ], + "bbox": [ + 502, + 149, + 868, + 843 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "4901", + "bbox": [ + 468, + 876, + 499, + 885 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "uncertainty-aware semantic consistency. IEEE Transactions on Circuits and Systems for Video Technology, 33(4):1740-1751, 2022. 1", + "[39] Aleksander Madry, Aleksandar Makelov, Ludwig Schmidt, Dimitris Tsipras, and Adrian Vladu. Towards deep learning models resistant to adversarial attacks. In 6th International Conference on Learning Representations, 2018. 1, 7", + "[40] Ananth Mahadevan and Michael Mathioudakis. Certifiable machine unlearning for linear models. arXiv preprint arXiv:2106.15093, 2021. 3, 7", + "[41] Neil G Marchant, Benjamin IP Rubinstein, and Scott Alfeld. Hard to forget: Poisoning attacks on certified machine unlearning. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 7691-7700, 2022. 1", + "[42] Brendan McMahan, Eider Moore, Daniel Ramage, Seth Hampson, and Blaise Aguera y Arcas. Communication-efficient learning of deep networks from decentralized data. In Artificial intelligence and statistics, 2017. 1", + "[43] Ronak Mehta, Sourav Pal, Vikas Singh, and Sathya N. Ravi. Deep unlearning via randomized conditionally independent hessian. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 10422-10431, June 2022. 1, 3", + "[44] Seth Neel, Aaron Roth, and Saeed Sharifi-Malvajerdi. Descent-to-delete: Gradient-based methods for machine unlearning. In Algorithmic Learning Theory, 2021. 1", + "[45] Nicolas Papernot, Patrick McDaniel, Arunesh Sinha, and Michael P Wellman. Sok: Security and privacy in machine learning. In 2018 IEEE European Symposium on Security and Privacy (EuroS&P), pages 399-414. IEEE, 2018. 1", + "[46] Jian Pei. A survey on data pricing: from economics to data science. IEEE Transactions on knowledge and Data Engineering, 2020. 5", + "[47] Hai Phan, My T Thai, Han Hu, Ruoming Jin, Tong Sun, and Dejing Dou. Scalable differential privacy with certified robustness in adversarial learning. In International Conference on Machine Learning, pages 7683-7694, 2020. 1", + "[48] NhatHai Phan, Minh N. Vu, Yang Liu, Ruoming Jin, Dejing Dou, Xintao Wu, and My T. Thai. Heterogeneous gaussian mechanism: Preserving differential privacy in deep learning with provable robustness. In Sarit Kraus, editor, Proceedings of the Twenty-Eighth International Joint Conference on Artificial Intelligence, pages 4753-4759, 2019. 1", + "[49] Ayush Sekhari, Jayadev Acharya, Gautam Kamath, and Ananda Theertha Suresh. Remember what you want to forget: Algorithms for machine unlearning. Advances in Neural Information Processing Systems, 34:18075-18086, 2021. 3, 4", + "[50] Uri Shaham, Yutaro Yamada, and Sahand Negahban. Understanding adversarial training: Increasing local stability of supervised models through robust optimization. Neurocomputing, 307:195-204, 2018. 3", + "[51] Reza Shokri, Marco Stronati, Congzheng Song, and Vitaly Shmatikov. Membership inference attacks against machine learning models. In 2017 IEEE Symposium on Security and Privacy, pages 3-18. IEEE, 2017. 1", + "[52] Liwei Song, Reza Shokri, and Prateek Mittal. Privacy risks of securing machine learning models against adversarial exam" + ], + "bbox": [ + 104, + 149, + 472, + 843 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "plies. In Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security, 2019. 1", + "[53] Qiheng Sun, Xiang Li, Jiayao Zhang, Li Xiong, Weiran Liu, Jinfei Liu, Zhan Qin, and Kui Ren. Shapleyfl: Robust federated learning based on shapley value. In Proceedings of the 29th ACM SIGKDD Conference on Knowledge Discovery and Data Mining, pages 2096-2108, 2023. 1", + "[54] Christian Szegedy, Wojciech Zaremba, Ilya Sutskever, Joan Bruna, Dumitru Erhan, Ian J. Goodfellow, and Rob Fergus. Intriguing properties of neural networks. In Yoshua Bengio and Yann LeCun, editors, 2nd International Conference on Learning Representations, 2014. 1", + "[55] Farnaz Tahmasebian, Jian Lou, and Li Xiong. Robustfed: a truth inference approach for robust federated learning. In Proceedings of the 31st ACM International Conference on Information & Knowledge Management, 2022. 1", + "[56] Pengfei Tang, Wenjie Wang, Jian Lou, and Li Xiong. Generating adversarial examples with distance constrained adversarial imitation networks. IEEE Transactions on Dependable and Secure Computing, 19(6):4145-4155, 2021.", + "[57] Anvith Thudi, Gabriel Deza, Varun Chandrasekaran, and Nicolas Papernot. Unrolling sgd: Understanding factors influencing machine unlearning. In 2022 IEEE 7th European Symposium on Security and Privacy (EuroS&P), pages 303-319. IEEE, 2022. 4", + "[58] Anvith Thudi, Hengrui Jia, Ilia Shumailov, and Nicolas Papernot. On the necessity of auditable algorithmic definitions for machine unlearning. In 31st USENIX Security Symposium (USENIX Security 22), pages 4007-4022, 2022. 1", + "[59] Boxi Wu, Jindong Gu, Zhifeng Li, Deng Cai, Xiaofei He, and Wei Liu. Towards efficient adversarial training on vision transformers. In European Conference on Computer Vision, pages 307-325, 2022. 1", + "[60] Yinjun Wu, Edgar Dobriban, and Susan Davidson. Deltagrad: Rapid retraining of machine learning models. In International Conference on Machine Learning, 2020. 1, 4", + "[61] Jingwen Ye, Yifang Fu, Jie Song, Xingyi Yang, Songhua Liu, Xin Jin, Mingli Song, and Xinchao Wang. Learning with recoverable forgetting. In European Conference on Computer Vision, pages 87-103, 2022. 1", + "[62] Xiaoyong Yuan, Pan He, Qile Zhu, and Xiaolin Li. Adversarial examples: Attacks and defenses for deep learning. IEEE transactions on neural networks and learning systems, 30(9):2805-2824, 2019. 1", + "[63] Sergey Zagoruyko and Nikos Komodakis. Wide residual networks. In British Machine Vision Conference, 2016. 6", + "[64] Guojun Zhang, Kaiwen Wu, Pascal Poupart, and Yaoliang Yu. Newton-type methods for minimax optimization. arXiv preprint arXiv:2006.14592, 2020. 5", + "[65] Peng-Fei Zhang, Guangdong Bai, Zi Huang, and Xin-Shun Xu. Machine unlearning for image retrieval: A generative scrubbing approach. In Proceedings of the 30th ACM International Conference on Multimedia, 2022. 1", + "[66] Xiaoyu Zhang, Yulin Jin, Tao Wang, Jian Lou, and Xiaofeng Chen. Purifier: Plug-and-play backdoor mitigation for pretrained models via anomaly activation suppression. In Proceedings of the 30th ACM International Conference on Multimedia, pages 4291-4299, 2022. 1" + ], + "bbox": [ + 502, + 149, + 868, + 840 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "4902", + "bbox": [ + 468, + 876, + 500, + 885 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MUter_ Machine Unlearning on Adversarially Trained Models/794014c8-e2b9-40ef-b0f6-0010a00c9a4d_model.json b/2023/MUter_ Machine Unlearning on Adversarially Trained Models/794014c8-e2b9-40ef-b0f6-0010a00c9a4d_model.json new file mode 100644 index 0000000000000000000000000000000000000000..43d7da876bcd2a35a4ed999b244099db279ebc06 --- /dev/null +++ b/2023/MUter_ Machine Unlearning on Adversarially Trained Models/794014c8-e2b9-40ef-b0f6-0010a00c9a4d_model.json @@ -0,0 +1,2807 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.096, + 0.009, + 0.172, + 0.047 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.232, + 0.006, + 0.816, + 0.049 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.189, + 0.182, + 0.782, + 0.202 + ], + "angle": 0, + "content": "MUt er: Machine Unlearning on Adversarily Trained Models" + }, + { + "type": "text", + "bbox": [ + 0.186, + 0.226, + 0.783, + 0.242 + ], + "angle": 0, + "content": "Junxu Liu\\(^{1,*}\\), Mingsheng Xue\\(^{2,*}\\), Jian Lou\\(^{3,6,\\dagger}\\), Xiaoyu Zhang\\(^{4}\\), Li Xiong\\(^{5}\\), Zhan Qin\\(^{3,6}\\)" + }, + { + "type": "text", + "bbox": [ + 0.142, + 0.242, + 0.83, + 0.272 + ], + "angle": 0, + "content": "1Renmin University of China 2Guangzhou Institute of Technology, Xidian University 3Zhejiang University 4Xidian University 5Emory University 6ZJU-Hangzhou Global Scientific and Technological Innovation Center" + }, + { + "type": "text", + "bbox": [ + 0.182, + 0.274, + 0.79, + 0.287 + ], + "angle": 0, + "content": "junxu_liu@ruc.edu.cn xuemingsheng@stu.xidian.edu.cn jian.lou@zju.edu.cn" + }, + { + "type": "text", + "bbox": [ + 0.223, + 0.29, + 0.748, + 0.302 + ], + "angle": 0, + "content": "xiaoyuzhang@xidian.edu.cn lxiong@emory.edu qinzhan@zju.edu.cn" + }, + { + "type": "title", + "bbox": [ + 0.251, + 0.332, + 0.324, + 0.345 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.36, + 0.474, + 0.71 + ], + "angle": 0, + "content": "Machine unlearning is an emerging task of removing the influence of selected training datapoints from a trained model upon data deletion requests, which echoes the widely enforced data regulations mandating the Right to be Forgotten. Many unlearning methods have been proposed recently, achieving significant efficiency gains over the naive baseline of retraining from scratch. However, existing methods focus exclusively on unlearning from standard training models and do not apply to adversarial training models (ATMs) despite their popularity as effective defenses against adversarial examples. During adversarial training, the training data are involved in not only an outer loop for minimizing the training loss, but also an inner loop for generating the adversarial perturbation. Such bi-level optimization greatly complicates the influence measure for the data to be deleted and renders the unlearning more challenging than standard model training with single-level optimization. This paper proposes a new approach called MUt er for unlearning from ATMs. We derive a closed-form unlearning step underpinned by a total Hessian-related data influence measure, while existing methods can mis-capture the data influence associated with the indirect Hessian part. We further alleviate the computational cost by introducing a series of approximations and conversions to avoid the most computationally demanding parts of Hessian inversions. The efficiency and effectiveness of MUt er have been validated through experiments on four datasets using both linear and neural network models." + }, + { + "type": "title", + "bbox": [ + 0.104, + 0.737, + 0.227, + 0.751 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.759, + 0.471, + 0.812 + ], + "angle": 0, + "content": "Machine learning (ML) models are increasingly applied to a broad range of applications, accompanied by growing concerns about their privacy and robustness issues. Both issues are actively studied in recent years [45]. On the" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.333, + 0.871, + 0.528 + ], + "angle": 0, + "content": "privacy side, model inversion attack [16] and membership inference attack [51] reveal that the trained ML model contains sensitive information of its training data, which can cause privacy loss for individuals contributing their data for model training. On the robustness side, adversarial example attack is one of the most well-recognized robustness attacks [24, 30, 39, 62]. It can easily fool an undefended model, e.g., standard training model (STM), to misclassify by a small adversarial perturbation on the input [9, 24, 39]. Many works focus either on the privacy [1, 35, 37, 42, 51] or on the robustness aspect [9, 33, 38, 53–56, 66], few works studied both. Yet, it is critical to consider privacy and robustness jointly [20, 27, 36, 41, 47, 48, 52] to build ML models to simultaneously meet data privacy regulations and ensure robustness against adversarial threats." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.53, + 0.87, + 0.608 + ], + "angle": 0, + "content": "In this paper, we target a new joint privacy-robustness problem to simultaneously meet emerging privacy regulations and ensure adversarial robustness of the model, which has not been examined before: how to efficiently and effectively remove the influence of a training datapoint from an adversarially trained model upon data deletion request?" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.609, + 0.871, + 0.791 + ], + "angle": 0, + "content": "The privacy need is driven by the widely enacted user data regulations that enforce the Right to be Forgotten, for example, the European Union's GDPR [17], the California Consumer Privacy Act (CCPA), and Canada's proposed Consumer Privacy Protection Act (CPPA). These regulations mandate the deletion of personal data upon user requests and can even include the deletion of models and algorithms derived from the user data, e.g., the Federal Trade Commission [15]. Machine unlearning [5,8] aims to obtain an updated model with the influence of the target datapoint removed in an effective and efficient way. That is, the updated model should be similar to the model obtained by the computationally expensive retraining-from-scratch approach, while consuming less computation [21-23,26,31,43,44,58,60,61,65]." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.793, + 0.871, + 0.845 + ], + "angle": 0, + "content": "The robustness is achieved by the adversarial training model (ATM) [3, 24, 30, 39, 59], which is a popular and effective defense for enhancing the model robustness against adversarial examples by creating and incorporating adver" + }, + { + "type": "page_footnote", + "bbox": [ + 0.12, + 0.822, + 0.224, + 0.833 + ], + "angle": 0, + "content": "*Equal contribution." + }, + { + "type": "page_footnote", + "bbox": [ + 0.123, + 0.833, + 0.242, + 0.844 + ], + "angle": 0, + "content": "† Corresponding Author." + }, + { + "type": "list", + "bbox": [ + 0.12, + 0.822, + 0.242, + 0.844 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.876, + 0.502, + 0.887 + ], + "angle": 0, + "content": "4892" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.144, + 0.148, + 0.833, + 0.314 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.102, + 0.323, + 0.871, + 0.39 + ], + "angle": 0, + "content": "Figure 1: ATM has two interdependent sets of optimization variables, model parameters and adversarial perturbations (yellow arrows), both of which contain nested training data influence (blue arrows). To remove such nested data influence, ATM unlearning requires the total Hessian that consists of both direct and indirect Hessian components (green solid lines). Existing unlearning methods designed for standard training models are inapplicable to ATM unlearning, because they only use direct Hessian information during the unlearning update and do not capture sufficient data influence (red dashed lines)." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.411, + 0.475, + 0.528 + ], + "angle": 0, + "content": "sarial examples into the training process. ATM is trained by a bi-level optimization with the model parameters as the outer-level variable and the adversarial perturbations as the inner-level variable. To the best of our knowledge, all existing unlearning methods focus solely on data removal from STM. As our analysis will reveal in Section 3, the existing methods cannot be applied to ATM unlearning without miscapturing the data influence to be removed, due to ATM's bi-level optimization structure." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.533, + 0.474, + 0.846 + ], + "angle": 0, + "content": "In this paper, we propose a new unlearning approach called MUt e r: M Machine Unlearning for data removal from adversarial training models. First, we define the ATM unlearning task in accordance with the mainstream machine unlearning standard. Second, we convert it to an ATM unlearning criteria derived from the optimality condition of ATM, which facilitates the derivation of the unlearning update for ATM. Meanwhile, existing unlearning methods designed for STM cannot satisfy the ATM unlearning criteria. As illustrated in Figure 1, ATM, as a bi-level optimization, has two sets of variables: model parameters and adversarial perturbations, which are interdependent and both contain training data information. In contrast, STM, as a single-level optimization, has only one set of variables: model parameters, which have a direct influence dependence on each training datapoint. Existing unlearning methods cannot sufficiently remove data influence from ATM because they fail to account for the indirect influence on the model parameters (i.e., miss the indirect Hessian part in Figure 1). That is, due to the coupled outer-inner optimization, any updates to the outer model parameters will incur further updates for both the adversarial perturbations and the model parameters. To address this, we derive a new closed-form unlearning update for ATM, which is underpinned by the total Hessian-based" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.411, + 0.871, + 0.514 + ], + "angle": 0, + "content": "influence measure. Third, based on the ATM unlearning update, we propose a three-stage unlearning framework to support successive unlearning requests for ATM, which enhances efficiency by selectively storing certain computations in memory. Last, we leverage Schur complement conversion and Neumann series approximation to avoid the computationally demanding and numerical unstable computations of Hessian matrix and its inversions." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.516, + 0.785, + 0.527 + ], + "angle": 0, + "content": "To summarize, our main contributions are:" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.528, + 0.87, + 0.592 + ], + "angle": 0, + "content": "1. We introduce the problem of unlearning from adversarial training models, which is a new and pressing challenge to simultaneously meet emerging privacy regulations and ensure the adversarial robustness of the model. To the best of our knowledge, it has not been studied in the existing literature." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.593, + 0.871, + 0.644 + ], + "angle": 0, + "content": "2. We derive a new unlearning update tailored to ATM unlearning, which has the total Hessian-based data influence measure to sufficiently account for the interdependence between inner and outer optimizations of ATM." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.644, + 0.871, + 0.709 + ], + "angle": 0, + "content": "3. We propose MUt er based on the proposed unlearning update, which supports successive unlearning requests for ATM and introduces a series of conversions and approximations for Hessian inversions to alleviate the computational cost and improve the numerical stability." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.71, + 0.871, + 0.762 + ], + "angle": 0, + "content": "4. We perform a comprehensive evaluation to verify that \\( MUter \\) achieves effective and efficient unlearning performance while maintaining the model accuracy and adversarial robustness, under two unlearning settings on four datasets." + }, + { + "type": "list", + "bbox": [ + 0.498, + 0.528, + 0.871, + 0.762 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.773, + 0.779, + 0.787 + ], + "angle": 0, + "content": "2. Preliminaries and Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.795, + 0.676, + 0.81 + ], + "angle": 0, + "content": "2.1. Setup and Notation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.818, + 0.871, + 0.846 + ], + "angle": 0, + "content": "Setup. Denote the training dataset with \\(n\\) training samples by \\(\\mathcal{D} = \\{(\\mathbf{x}_1,y_1),\\ldots ,(\\mathbf{x}_n,y_n)\\}\\) , where for \\(\\forall i\\in\\)" + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.877, + 0.502, + 0.887 + ], + "angle": 0, + "content": "4893" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.102, + 0.148, + 0.471, + 0.202 + ], + "angle": 0, + "content": "\\(\\{1,\\dots ,n\\}\\) \\(\\mathbf{x}_i\\in \\mathbb{R}^d\\) is the \\(d\\) -dimensional feature vector, and \\(y_{i}\\in \\mathbb{R}\\) is the corresponding response/label. Denote the loss function by \\(l(\\omega ,\\mathbf{x}_i)\\) , where \\(\\omega \\in \\mathbb{R}^p\\) represents the vector of the \\(p\\) -dimensional model parameters." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.205, + 0.473, + 0.257 + ], + "angle": 0, + "content": "Standard Training Model (STM). Standard training model refers to the empirical risk minimization model: \\(\\omega_{std}^{*} = \\mathrm{argmin}_{\\omega}\\frac{1}{n}\\sum_{i = 1}^{n}l(\\omega ,\\mathbf{x}_i)\\), where \\(\\omega \\in \\mathbb{R}^p\\) is the model parameter variable." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.26, + 0.473, + 0.322 + ], + "angle": 0, + "content": "Adversarial Training Model (ATM). Adversarial training model is an effective defense against robustness threats posed by the adversarial attack. In this paper, we adopt one of the most widely-used ATM variants to consider the following bi-level robust optimization formulation [30, 50]," + }, + { + "type": "equation", + "bbox": [ + 0.154, + 0.331, + 0.473, + 0.361 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {\\omega} ^ {*} = \\underset {\\boldsymbol {\\omega}} {\\operatorname {a r g m i n}} \\frac {1}{n} \\sum_ {i = 1} ^ {n} \\max _ {\\delta_ {i} \\in \\mathcal {B} (\\mathbf {x} _ {i}, r)} l (\\boldsymbol {\\omega}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i}), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.37, + 0.473, + 0.456 + ], + "angle": 0, + "content": "where the inner optimization is to find adversarial perturbation \\(\\delta_{i}\\) from the constraint set \\(\\mathcal{B}(\\mathbf{x}_i,r)\\) to maximize the loss and the outer optimization is to find the model parameter \\(\\omega\\) that minimizes the loss for the adversarially perturbed examples. To make the interdependence between the outer variable \\(\\omega\\) and the inner variable \\(\\delta\\) more explicit, we further introduce an auxiliary function \\(\\delta_{i}(\\omega)\\) given by" + }, + { + "type": "equation", + "bbox": [ + 0.188, + 0.464, + 0.473, + 0.486 + ], + "angle": 0, + "content": "\\[\n\\delta_ {i} (\\boldsymbol {\\omega}) = \\underset {\\boldsymbol {\\delta} _ {i} \\in \\mathcal {B} (\\mathbf {x} _ {i}, r)} {\\operatorname {a r g m a x}} l \\left(\\boldsymbol {\\omega}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i}\\right). \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.498, + 0.473, + 0.591 + ], + "angle": 0, + "content": "Machine Unlearning for Adversarial Training Models. Definition 1 below specifies the ATM unlearning task in consistency with the mainstream unlearning standard. For notational simplicity, we focus on single-point removal in the paper, but the analysis and algorithms developed in the paper are generalizable to batch removal as well (please refer to Appendix B.5 for the batch removal generalization)." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.599, + 0.473, + 0.661 + ], + "angle": 0, + "content": "Definition 1. (Machine Unlearning for Adversarial Training Models) For a trained adversarial training model as in eq.(1), let \\(\\forall i^{\\dagger}\\in \\{1,\\dots ,n\\}\\) be the index of a datapoint to be forgotten. The ATM after machine unlearning unlearning (forgetting datapoint \\(i^{\\dagger}\\)) has parameter \\(\\omega_{-i^{\\dagger}}^{*}\\) as follows," + }, + { + "type": "equation", + "bbox": [ + 0.117, + 0.672, + 0.473, + 0.703 + ], + "angle": 0, + "content": "\\[\n\\omega_ {- i ^ {\\dagger}} ^ {*} = \\underset {\\omega} {\\operatorname {a r g m i n}} \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\max _ {\\delta_ {i} \\in \\mathcal {B} (\\mathbf {x} _ {i}, r)} l (\\omega , \\mathbf {x} _ {i} + \\delta_ {i}). \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.713, + 0.473, + 0.805 + ], + "angle": 0, + "content": "Retraining-from-scratch serves as the golden standard and also a naive baseline to obtain the unlearned ATM \\(\\omega_{-i\\dagger}^{*}\\), which is prohibitive in computation, especially for ATM with both inner maximization and outer minimization. Hence, the goal of machine unlearning for ATM is to approximately remove \\(i^{\\dagger}\\)'s influence with great computational efficiency improvement over retraining-from-scratch." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.807, + 0.473, + 0.846 + ], + "angle": 0, + "content": "Notation. For a twice differentiable \\(l(\\omega, \\mathbf{x} + \\delta)\\), \\(\\nabla_{\\omega} l(\\omega, \\mathbf{x} + \\delta)\\) denotes the direct gradient of \\(l\\) with respect to (w.r.t.) \\(\\omega\\) and \\(\\partial_{\\omega \\omega} l(\\omega, \\mathbf{x} + \\delta)\\), \\(\\partial_{\\omega \\delta} l(\\omega, \\mathbf{x} + \\delta)\\), \\(\\partial_{\\delta \\omega} l(\\omega, \\mathbf{x} + \\delta)\\)," + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.149, + 0.868, + 0.174 + ], + "angle": 0, + "content": "\\(\\partial_{\\delta \\delta}l(\\omega ,\\mathbf{x} + \\delta)\\) denote the second order partial derivatives w.r.t. \\(\\omega\\) and \\(\\delta\\) , correspondingly. The total Hessian is" + }, + { + "type": "equation", + "bbox": [ + 0.5, + 0.183, + 0.868, + 0.223 + ], + "angle": 0, + "content": "\\[\n\\mathrm {D} _ {\\omega \\omega} l (\\omega , \\mathbf {x} + \\delta) := \\overbrace {\\partial_ {\\omega \\omega} l (\\omega , \\mathbf {x} + \\delta)} ^ {\\text {D i r e c t H e s s i a n}} - \\overbrace {\\partial_ {\\omega \\delta} \\partial_ {\\delta \\delta} ^ {- 1} \\partial_ {\\delta \\omega} l (\\omega , \\mathbf {x} + \\delta)} ^ {\\text {I n d i r e c t H e s s i a n}}, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.223, + 0.87, + 0.277 + ], + "angle": 0, + "content": "where \\(\\partial_{\\omega \\delta}\\partial_{\\delta \\delta}^{-1}\\partial_{\\delta \\omega}l(\\omega ,\\mathbf{x} + \\boldsymbol {\\delta}) = \\partial_{\\omega \\delta}l(\\omega ,\\mathbf{x} + \\boldsymbol {\\delta})(\\partial_{\\delta \\delta}l(\\omega ,\\mathbf{x} + \\boldsymbol {\\delta}))^{-1}\\partial_{\\delta \\omega}l(\\omega ,\\mathbf{x} + \\boldsymbol {\\delta})\\) .We also use the short hand notation \\(l_i^*\\coloneqq l(\\pmb {\\omega}^*,\\mathbf{x}_i + \\delta_i(\\pmb {\\omega}^*))\\) and similarly introduce \\(\\nabla_{\\omega}l_{i}^{*},\\partial_{\\omega \\omega}l_{i}^{*},\\partial_{\\omega \\delta}l_{i}^{*},\\partial_{\\delta \\omega}l_{i}^{*},\\partial_{\\delta \\delta}l_{i}^{*}\\)" + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.285, + 0.635, + 0.297 + ], + "angle": 0, + "content": "2.2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.305, + 0.87, + 0.41 + ], + "angle": 0, + "content": "We briefly review existing machine unlearning methods. They are exclusively focused on STM and are not applicable to ATM unlearning with sufficient data influence removal. We provide a brief overview of current machine unlearning methods, which are focused exclusively on unlearning for STM and are not applicable to ATM unlearning with sufficient data influence removal. Thus, it is necessary to develop a new unlearning approach specific to ATM unlearning." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.412, + 0.87, + 0.607 + ], + "angle": 0, + "content": "Exact Machine Unlearning. Exact unlearning methods perform exact retraining but manage to do so only on a selective portion of the dataset to avoid retraining on the entire dataset. Some exact unlearning methods are designed for specific models like Naive Bayes [8], quantized k-means [19], and random forests [6]. Recently, SISA [5] proposes a more general exact unlearning strategy. It divides the training data into multiple disjoint shards during the training phase, and retransmits only on the shard that contains the data to be removed during the unlearning phase. Later, [11] and [12] extend the SISA strategy to unlearning for recommendation systems and graph neural networks. However, the SISA strategy requires different shards to be independently updatable from each other, which is not the case for ATM due to its interdependent bi-level structure." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.611, + 0.87, + 0.846 + ], + "angle": 0, + "content": "Approximate Machine Unlearning. Approximate unlearning methods seek the updated model parameters to approximately satisfy the optimality condition of the objective function on the remaining data, which can be roughly divided into three categories. 1) Unlearning with direct Hessian-related terms: [22, 26, 31, 34, 40, 43, 49] propose Newton step-based unlearning updates, where the Newton curvature matrices are direct Hessian-related terms. These methods also inject Gaussian noise to further destroy the remaining data influence due to the discrepancy between the exact unlearning standard and the approximate unlearning criteria. Some works also consider to alleviate the computational cost of the Hessian. For example, [22] proposes to approximate the direct Hessian with Fisher information matrix; [43] proposes to avoid dealing with the entire direct Hessian by selecting small Hessian blocks for unlearning update. 2) Unlearning based on neural tangent kernel (NTK) theory: they approximates the training phase by NTK theory, where [23] regards" + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.877, + 0.501, + 0.887 + ], + "angle": 0, + "content": "4894" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.102, + 0.149, + 0.474, + 0.306 + ], + "angle": 0, + "content": "the training as an approximately linear change and [21] divides the training phase into two stages, one is the linear standard training on the core dataset, and the other is the linear finetuning on the target dataset. Both works then apply direct Hessian-related unlearning updates. 3) Unlearning by tracking the Stochastic Gradient Descent (SGD) path during training: DeltaGrad [60] and unrollSGD [57] propose to track and reverse the SGD optimization path during the training phase. However, all above methods do not consider the interdependence between model parameters and adversarial perturbations of ATM, which cannot holistically capture the data influence, as will be detailed in the next section." + }, + { + "type": "title", + "bbox": [ + 0.103, + 0.315, + 0.351, + 0.33 + ], + "angle": 0, + "content": "3. Unlearning Update for ATM" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.339, + 0.473, + 0.379 + ], + "angle": 0, + "content": "ATM Unlearning Criteria. We begin by converting eq.(3) in Definition 1 to the optimality condition form of ATM based on Danskin's Theorem [13]," + }, + { + "type": "equation", + "bbox": [ + 0.16, + 0.384, + 0.473, + 0.42 + ], + "angle": 0, + "content": "\\[\n\\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\nabla_ {\\omega} l \\left(\\omega_ {- i ^ {\\dagger}} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\omega_ {- i ^ {\\dagger}} ^ {*}\\right)\\right) = 0, \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.425, + 0.474, + 0.492 + ], + "angle": 0, + "content": "which provides more convenience to the follow-up ATM unlearning designs. Our goal is to find a closed-form unlearning update \\(\\mathcal{U}(\\boldsymbol{\\omega}^*, i^\\dagger)\\) such that the unlearning model with parameter \\(\\boldsymbol{\\omega}^u = \\boldsymbol{\\omega}^* + \\mathcal{U}(\\boldsymbol{\\omega}^*, i^\\dagger)\\) will satisfy the following ATM unlearning criteria," + }, + { + "type": "equation", + "bbox": [ + 0.172, + 0.496, + 0.473, + 0.533 + ], + "angle": 0, + "content": "\\[\n\\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\nabla_ {\\omega} l \\left(\\omega^ {u}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\omega^ {u}\\right)\\right) \\approx 0. \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.538, + 0.474, + 0.65 + ], + "angle": 0, + "content": "Cause of Inapplicability of Existing Approximate Unlearning Methods. Before deriving our ATM unlearning update, we recall the design rationale common to existing approximate machine unlearning methods and point out why they fail to sufficiently remove the data influence for ATM. Despite the varying forms of specific unlearning updates, existing approximate unlearning methods all exploit the trained model parameter \\(\\omega^{*}\\) and connect it with the unlearned model \\(\\omega^{u}\\) by first-order expansion of \\(\\nabla_{\\omega}l\\) around \\(\\omega^{*}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.164, + 0.655, + 0.473, + 0.74 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\nabla_ {\\omega} l \\left(\\omega^ {u}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\omega^ {u}\\right)\\right) \\\\ \\approx \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\left[ \\nabla_ {\\omega} l \\left(\\omega^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\omega^ {u}\\right)\\right) \\right. \\tag {7} \\\\ \\left. + \\partial_ {\\omega} \\omega l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {u}\\right)\\right) \\left(\\boldsymbol {\\omega} ^ {u} - \\boldsymbol {\\omega} ^ {*}\\right) \\right]. \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.743, + 0.474, + 0.793 + ], + "angle": 0, + "content": "Existing methods then obtain the updated \\(\\omega^u\\) by letting the right hand side of eq.(7) approach 0 and exploiting the optimality condition of \\(\\omega^{*}\\). For example, the influence function-inspired unlearning [26, 49] has \\(\\mathbf{u}(\\boldsymbol{\\omega}^{*}, i^{\\dagger}) =\\)" + }, + { + "type": "equation", + "bbox": [ + 0.106, + 0.798, + 0.473, + 0.845 + ], + "angle": 0, + "content": "\\[\n\\left[ \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\underbrace {\\partial_ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {u}\\right)\\right)} _ {\\text {D i r e c t H e s s i a n - o n l y}} \\right] ^ {- 1} \\nabla_ {\\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\delta_ {i ^ {\\dagger}} \\left(\\boldsymbol {\\omega} ^ {u}\\right)\\right). \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.149, + 0.871, + 0.279 + ], + "angle": 0, + "content": "However, there are two obvious issues when applying the above design rationale to the ATM unlearning: 1) the conversion from eq.(7) to eq.(8) requires \\(\\sum_{i=1}^{n} \\nabla_{\\omega} l(\\omega^{*}, \\mathbf{x}_{i} + \\delta_{i}(\\omega^{u})) = 0\\), which does not hold in general. Rather, the optimality condition only promises \\(\\sum_{i=1}^{n} \\nabla_{\\omega} l(\\omega^{*}, \\mathbf{x}_{i} + \\delta_{i}(\\omega^{*})) = 0\\); 2) the Hessian \\(\\partial_{\\omega \\omega} l(\\omega^{*}, \\mathbf{x}_{i} + \\delta_{i}(\\omega^{u}))\\) and gradient \\(\\nabla_{\\omega} l(\\omega^{*}, \\mathbf{x}_{i} + \\delta_{i}(\\omega^{u}))\\) in eq.(8) are not commutable without knowing \\(\\omega^{u}\\) in advance. We point out that the root cause of both issues is that eq.(7) fails to account for the interdependence between \\(\\omega\\) and \\(\\delta\\) as in eq.(2)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.282, + 0.871, + 0.36 + ], + "angle": 0, + "content": "Proposed ATM Unlearning Update. The above root cause propels us to derive a new unlearning update that can holistically capture the nested data influence. To account for the interdependence between the adversarial perturbations and the model parameters in eq.(2), we take the complete expansion w.r.t. both \\(\\omega\\) and \\(\\delta\\) as in Lemma 1 below." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.367, + 0.871, + 0.408 + ], + "angle": 0, + "content": "Lemma 1. By expansion around both \\(\\omega^{*}\\) and \\(\\delta (\\omega^{*})\\), the approximate machine unlearning model parameter \\(\\omega^u\\) and the original model parameter \\(\\omega^{*}\\) has the following relation," + }, + { + "type": "equation", + "bbox": [ + 0.518, + 0.415, + 0.869, + 0.531 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\nabla_ {\\boldsymbol {\\omega}} l (\\boldsymbol {\\omega} ^ {u}, \\mathbf {x} _ {i} + \\delta_ {i} (\\boldsymbol {\\omega} ^ {u})) \\\\ \\approx \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\left[ \\nabla_ {\\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {*}\\right)\\right) \\right. \\tag {9} \\\\ + \\partial_ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {*}\\right)\\right) \\left(\\boldsymbol {\\omega} ^ {u} - \\boldsymbol {\\omega} ^ {*}\\right) \\\\ \\left. + \\partial_ {\\boldsymbol {\\omega} \\delta} l (\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} (\\boldsymbol {\\omega} ^ {*})) (\\delta_ {i} (\\boldsymbol {\\omega} ^ {u}) - \\delta_ {i} (\\boldsymbol {\\omega} ^ {*})) \\right]. \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.538, + 0.732, + 0.551 + ], + "angle": 0, + "content": "Proof. Please refer to Appendix B.1." + }, + { + "type": "image", + "bbox": [ + 0.853, + 0.539, + 0.869, + 0.548 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.559, + 0.871, + 0.625 + ], + "angle": 0, + "content": "The last line of eq.(9) is key to the sufficient removal of the data influence from ATM, which captures the interdependence between the adversarial perturbations and the model parameters. Based on Lemma 1, we can derive the ATM unlearning update in closed-form in Theorem 1 below." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.63, + 0.871, + 0.681 + ], + "angle": 0, + "content": "Theorem 1. Consider the adversarial training model with trained model parameter \\(\\omega^{*}\\) as in eq.(1). Let \\((\\mathbf{x}_{i^{\\dagger}},y_{i^{\\dagger}})\\) be a datapoint in the training dataset to be forgotten. Let the machine learning update \\(\\mathcal{U}(\\boldsymbol {\\omega}^*,i^{\\dagger})\\) take the following form" + }, + { + "type": "equation", + "bbox": [ + 0.525, + 0.687, + 0.869, + 0.745 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {U} \\left(\\boldsymbol {\\omega} ^ {*}, i ^ {\\dagger}\\right) := \\left[ \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\underbrace {\\mathrm {D} _ {\\boldsymbol {\\omega} \\boldsymbol {\\omega}} l \\left(\\boldsymbol {\\omega} ^ {*} , \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {*}\\right)\\right)} _ {\\text {T o t a l H e s s i a n}} \\right] ^ {- 1} \\tag {10} \\\\ \\cdot \\left[ \\nabla_ {\\boldsymbol {\\omega}} l (\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\delta_ {i ^ {\\dagger}} (\\boldsymbol {\\omega} ^ {*})) \\right]. \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.871, + 0.791 + ], + "angle": 0, + "content": "Then, the unlearning model with updated parameters \\(\\omega^u \\coloneqq \\omega^* + \\mathcal{U}(\\omega^*, i^\\dagger)\\) satisfies the approximate unlearning criteria for the adversarial training model in eq.(6)." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.797, + 0.733, + 0.81 + ], + "angle": 0, + "content": "Proof. Please refer to Appendix B.1." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.818, + 0.871, + 0.845 + ], + "angle": 0, + "content": "It turns out that the ATM unlearning in eq.(10) requires both direct Hessian and indirect Hessian (i.e., total Hessian" + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.877, + 0.502, + 0.887 + ], + "angle": 0, + "content": "4895" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.102, + 0.149, + 0.473, + 0.215 + ], + "angle": 0, + "content": "in eq.(4)) to sufficiently capture the data influence, while previous methods for the STM unlearning have only the direct Hessian-related part (e.g., eq.(8)). The total Hessian term also appears in the second-order bi-level optimization literature, e.g., the Complete Newton method in [64]." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.219, + 0.474, + 0.311 + ], + "angle": 0, + "content": "A New Influence Function. Finally, we would like to remark that eq.(10) can be used to define a new influence function as follows to measure the nested data influence of a data point for ATM. It could serve as an independent interest, for example, to measure the marginal contribution of a data point to the model for valuation in data market [46] and influence-based defense against data poisoning attacks [18]." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.321, + 0.473, + 0.369 + ], + "angle": 0, + "content": "Definition 2. (Leave-one-out Adversarial Influence Function) For the adversarial training model given in eq.(1), the leave-one-out adversarial influence function for any \\((\\mathbf{x},y)\\) in the training dataset is defined as" + }, + { + "type": "equation", + "bbox": [ + 0.106, + 0.38, + 0.466, + 0.41 + ], + "angle": 0, + "content": "\\[\n\\mathcal {I} (\\mathbf {x}, y) = - \\left[ \\frac {1}{n} \\sum_ {i = 1} ^ {n} \\mathrm {D} _ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i} ^ {*}\\right) \\right] ^ {- 1} \\nabla_ {\\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} + \\boldsymbol {\\delta} ^ {*}\\right).\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.422, + 0.474, + 0.526 + ], + "angle": 0, + "content": "Definition 2 utilizes total Hessian instead of direct Hessian-only as in [32], which captures the interdependence between adversarial perturbations and model parameters. This is different from recent work [14] which defines the adversarial influence function as a training sample's influence difference between two models: an STM and an ATM, while Definition 2 measures a training sample's influence difference when it is in or out for a single ATM." + }, + { + "type": "title", + "bbox": [ + 0.102, + 0.541, + 0.328, + 0.555 + ], + "angle": 0, + "content": "4. Proposed Method: MUt er" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.564, + 0.472, + 0.707 + ], + "angle": 0, + "content": "Equipped with the ATM unlearning update, we propose MUt er, a three-stage unlearning method for ATM, which has two design considerations: 1) Support the more practical successive unlearning setting where multiple data points can be forgotten in sequence by keeping a selective variable set in memory (Sec.4.1); 2) Reduce the per-unlearning computational cost by introducing more efficient approximations and conversions to avoid direct computations of the most computational demanding Hessian inversions (Sec.4.2). The overall framework of MUt er is illustrated in Figure 2. We also present the complete algorithm in Appendix B.4." + }, + { + "type": "title", + "bbox": [ + 0.102, + 0.717, + 0.295, + 0.731 + ], + "angle": 0, + "content": "4.1. Three Stages of MUt er" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.742, + 0.473, + 0.81 + ], + "angle": 0, + "content": "Successive Unlearning Setting. Denote the indices of datapoints that have already been forgotten at timestamp \\( r \\) by \\( \\{i_1^\\dagger, \\ldots, i_r^\\dagger\\} \\), the index of datapoint to be forgotten at timestamp \\( r + 1 \\) by \\( i_{r + 1}^\\dagger = i^\\dagger \\). Corollary 1 below extends Theorem 1 to support successive unlearning for ATM." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.82, + 0.473, + 0.845 + ], + "angle": 0, + "content": "Corollary 1. Considering the successive unlearning setting, let the machine unlearning update at the \\( r + 1 \\)-th timestamp" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.148, + 0.736, + 0.163 + ], + "angle": 0, + "content": "\\(\\mathfrak{U}_r(\\omega^*, i_{r+1}^\\dagger)\\) take the following form" + }, + { + "type": "equation", + "bbox": [ + 0.508, + 0.173, + 0.788, + 0.22 + ], + "angle": 0, + "content": "\\[\n\\mathcal {U} _ {r} \\left(\\boldsymbol {\\omega} ^ {*}, i _ {r + 1} ^ {\\dagger}\\right) := \\left\\{\\overbrace {\\left[ \\sum_ {i = 1} ^ {n} \\mathrm {D} _ {\\boldsymbol {\\omega} \\boldsymbol {\\omega}} l \\left(\\boldsymbol {\\omega} ^ {*} , \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i} ^ {*}\\right) \\right]} ^ {\\mathcal {M} _ {0} [ \\mathrm {D} _ {\\boldsymbol {\\omega} \\boldsymbol {\\omega}} ]} - \\right.\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.512, + 0.223, + 0.869, + 0.279 + ], + "angle": 0, + "content": "\\[\n\\overbrace {\\left[ \\sum_ {i = i _ {1} ^ {\\dagger}} ^ {i _ {r} ^ {\\dagger}} \\mathrm {D} _ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i} ^ {*}\\right) \\right] - \\left[ \\mathrm {D} _ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i \\dagger} + \\boldsymbol {\\delta} _ {i \\dagger} ^ {*}\\right) \\right]} ^ {\\text {P a r t o f} \\mathcal {M} _ {r} [ \\mathrm {D} _ {\\omega \\omega} ]} ^ {- 1} \\tag {11}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.513, + 0.282, + 0.802, + 0.338 + ], + "angle": 0, + "content": "\\[\n\\cdot \\overbrace {\\left[ \\sum_ {i = i _ {1} ^ {\\dagger}} ^ {i _ {r} ^ {\\dagger}} \\nabla_ {\\omega} l (\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i} ^ {*}) + \\nabla_ {\\omega} l (\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\boldsymbol {\\delta} _ {i ^ {\\dagger}} ^ {*}) \\right]} ^ {\\mathcal {M} _ {r} [ \\nabla_ {\\boldsymbol {\\omega}} ]}.\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.348, + 0.871, + 0.387 + ], + "angle": 0, + "content": "Then, the unlearning model with updated parameters \\(\\omega_{r + 1}^{u}\\coloneqq \\omega^{*} + \\mathbf{U}_{r}(\\boldsymbol{\\omega}^{*},i_{r + 1}^{\\dagger})\\) satisfies the approximate unlearning criteria for the adversarial training model in eq.(6)." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.397, + 0.732, + 0.411 + ], + "angle": 0, + "content": "Proof. Please refer to Appendix B.2." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.426, + 0.871, + 0.543 + ], + "angle": 0, + "content": "Stage I. Pre-Unlearning. According to Corollary 1, it is a natural idea to pre-compute and keep in memory the total Hessian \\(\\left[\\sum_{i=1}^{n} \\mathsf{D}_{\\omega \\omega} l(\\boldsymbol{\\omega}^*, \\mathbf{x}_i + \\boldsymbol{\\delta}_i^*)\\right]\\) once the ATM is trained and before responding to unlearning requests, since it does not depend on the new point to be removed. Thus, we initialize a memory set \\(\\mathcal{M}_0\\) at \\(r = 0\\), which has three memory parts: \\(\\mathcal{M}_0[\\mathsf{D}_{\\omega \\omega}]\\) for \\(\\left[\\sum_{i=1}^{n} \\mathsf{D}_{\\omega \\omega} l(\\boldsymbol{\\omega}^*, \\mathbf{x}_i + \\boldsymbol{\\delta}_i^*)\\right]\\), \\(\\mathcal{M}_0[\\boldsymbol{\\omega}^*]\\) for \\(\\boldsymbol{\\omega}^*\\), and \\(\\mathcal{M}_0[\\nabla_{\\boldsymbol{\\omega}}]\\) for \\(\\nabla_{\\boldsymbol{\\omega}} = \\mathbf{0}\\) at \\(r = 0\\)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.546, + 0.87, + 0.706 + ], + "angle": 0, + "content": "Stage II. Unlearning. Upon receiving a new unlearning request to forget the \\(i^{\\dagger}\\)-th datapoint at timestamp \\(r + 1\\), Corollary 1 indicates that it suffices to compute the total Hessian and gradient only on \\(i^{\\dagger}\\) rather than the entire training set, once the memory is set up and maintained. We evaluate the following three parts in sequence: 1) The gradient on \\(i^{\\dagger} \\colon \\nabla_{\\omega} l(\\boldsymbol{\\omega}^{*}, \\mathbf{x}_{i^{\\dagger}} + \\boldsymbol{\\delta}_{i^{\\dagger}}^{*})\\); 2) The total Hessian on \\(i^{\\dagger} \\colon \\mathrm{D}_{\\omega} \\omega l(\\boldsymbol{\\omega}^{*}, \\mathbf{x}_{i^{\\dagger}} + \\boldsymbol{\\delta}_{i^{\\dagger}}^{*})\\); 3) The unlearning update \\(\\mathcal{U}_r(\\boldsymbol{\\omega}^*, i_{r+1}^{\\dagger})\\) in eq.(11) and the updated parameters \\(\\boldsymbol{\\omega}_{r+1}^u\\). In addition, we can also inject Gaussian noise by \\(\\boldsymbol{\\omega}_{r+1}^u + \\mathbf{n}\\) with \\(\\mathbf{n} \\sim \\mathcal{N}(0, \\sigma^2 \\mathbf{I})\\) to further smooth the remaining data influence to the discrepancy between eq.(3) and eq.(6)." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.709, + 0.87, + 0.735 + ], + "angle": 0, + "content": "Stage III. Post-Unlearning. To support subsequent unlearning requests, we update \\(\\mathcal{M}_{r + 1}\\) based on Corollary 1:" + }, + { + "type": "equation", + "bbox": [ + 0.515, + 0.745, + 0.869, + 0.761 + ], + "angle": 0, + "content": "\\[\n\\mathcal {M} _ {r + 1} \\left[ \\mathrm {D} _ {\\omega \\omega} \\right] = \\mathcal {M} _ {r} \\left[ \\mathrm {D} _ {\\omega \\omega} \\right] - \\mathrm {D} _ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\boldsymbol {\\delta} _ {i ^ {\\dagger}} ^ {*}\\right); \\tag {12}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.522, + 0.762, + 0.869, + 0.777 + ], + "angle": 0, + "content": "\\[\n\\mathcal {M} _ {r + 1} [ \\nabla_ {\\omega} ] = \\mathcal {M} _ {r} [ \\nabla_ {\\omega} ] + \\nabla_ {\\omega} l \\left(\\omega^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\boldsymbol {\\delta} _ {i ^ {\\dagger}} ^ {*}\\right), \\tag {13}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.788, + 0.868, + 0.824 + ], + "angle": 0, + "content": "where the former is the online update for \\(\\left[\\sum_{i=1}^{n} \\mathrm{D}_{\\omega \\omega} l\\left(\\omega^{*}, \\mathbf{x}_{i} + \\boldsymbol{\\delta}_{i}^{*}\\right)\\right] - \\left[\\sum_{i=i_{1}^{\\dagger}}^{i_{1}^{\\dagger} + 1} \\mathrm{D}_{\\omega \\omega} l\\left(\\omega^{*}, \\mathbf{x}_{i} + \\boldsymbol{\\delta}_{i}^{*}\\right)\\right]\\)" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.824, + 0.802, + 0.848 + ], + "angle": 0, + "content": "and the latter is for \\(\\left[\\sum_{i = i_1}^{i_{r + 1}}\\nabla_{\\omega}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_i + \\boldsymbol{\\delta}_i^*)\\right]\\)." + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.877, + 0.502, + 0.887 + ], + "angle": 0, + "content": "4896" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.126, + 0.147, + 0.846, + 0.272 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.102, + 0.28, + 0.871, + 0.335 + ], + "angle": 0, + "content": "Figure 2: The proposed MUt er framework. Stage I: the pre-unlearning stage prepares the initial memory \\(\\mathcal{M}_0[\\mathbb{D}_{\\omega \\omega}],\\mathcal{M}_0[\\nabla_{\\omega}],\\mathcal{M}_0[\\omega^* ]\\) . Stage II: the unlearning stage computes the total Hessian and gradient on the data to be forgotten and computes the ATM unlearning update by solving a linear system. Stage II: the post-unlearning stage updates \\(\\mathcal{M}_{r + 1}[\\mathbb{D}_{\\omega \\omega}]\\) and \\(\\mathcal{M}_{r + 1}[\\nabla_{\\omega}]\\) to be prepared for the next unlearning request." + }, + { + "type": "title", + "bbox": [ + 0.102, + 0.355, + 0.466, + 0.37 + ], + "angle": 0, + "content": "4.2. Unlearning without Direct Hessian Inversions" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.376, + 0.474, + 0.484 + ], + "angle": 0, + "content": "We now present the approximations and conversions to circumvent the most computationally expensive and potentially numerical unstable parts in the three stages, which are three Hessian matrix inversions: (Inv-1) The total Hessian inversion of \\(\\left[\\mathcal{M}_r[\\mathrm{D}_{\\omega \\omega}] - \\mathrm{D}_{\\omega \\omega}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_{i^\\dagger} + \\boldsymbol{\\delta}_{i^\\dagger}^*)\\right]^{-1}\\); (Inv-2) The partial Hessian inversion of \\(\\partial_{\\delta \\delta}^{-1}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_{i^\\dagger} + \\boldsymbol{\\delta}_{i^\\dagger}^*)\\) inside the total Hessian in Stage II; (Inv-3) The same \\(\\partial_{\\delta \\delta}^{-1}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_{i^\\dagger} + \\boldsymbol{\\delta}_{i^\\dagger}^*)\\) but in Stage I & III." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.487, + 0.475, + 0.58 + ], + "angle": 0, + "content": "Avoid Matrix Inversions (Inv-1/2) jointly by Schur Complement Conversion. After expanding the total Hessian as in eq.(4), we can reorganize \\(\\left[\\mathcal{M}_r[\\mathbb{D}_{\\omega \\omega}] - \\mathbb{D}_{\\omega \\omega}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_{i^\\dagger} + \\delta_{i^\\dagger}^*)\\right]\\) into the following form \\(\\mathbf{S} = \\left[\\mathcal{M}_r[\\mathbb{D}_{\\omega \\omega}] - \\partial_{\\omega \\omega}l_{i^\\dagger}^*\\right] - \\left[-\\partial_{\\omega \\delta}\\partial_{\\delta \\delta}^{-1}\\partial_{\\delta \\omega}l_{i^\\dagger}^*\\right]\\), which can be regarded as the Schur complement of the block matrix \\(\\mathbf{H}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.109, + 0.588, + 0.472, + 0.63 + ], + "angle": 0, + "content": "\\[\n\\mathbf {H} = \\left[ \\begin{array}{l l} \\mathbf {H} _ {1 1} & \\mathbf {H} _ {1 2} \\\\ \\mathbf {H} _ {2 1} & \\mathbf {H} _ {2 2} \\end{array} \\right] = \\left[ \\begin{array}{c c} \\mathcal {M} _ {r} [ \\mathrm {D} _ {\\omega \\omega} ] - \\partial_ {\\omega \\omega} l _ {i ^ {\\dagger}} ^ {*} & \\partial_ {\\omega \\delta} l _ {i ^ {\\dagger}} ^ {*} \\\\ \\partial_ {\\delta \\omega} l _ {i ^ {\\dagger}} ^ {*} & - \\partial_ {\\delta \\delta} l _ {i ^ {\\dagger}} ^ {*} \\end{array} \\right]. \\tag {14}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.64, + 0.472, + 0.693 + ], + "angle": 0, + "content": "By Schur complement lemma, we can find the inversion of \\(\\mathbf{S}\\) to the inversion of \\(\\mathbf{H}\\), then the unlearning update is equivalent to solving a linear system, as summarized in the following Theorem." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.701, + 0.472, + 0.727 + ], + "angle": 0, + "content": "Theorem 2. The unlearning update \\(\\mathfrak{U}_r(\\omega^*, i_{r+1}^\\dagger)\\) in eq.(11) can be equivalently computed by solving the linear system:" + }, + { + "type": "equation", + "bbox": [ + 0.107, + 0.734, + 0.486, + 0.762 + ], + "angle": 0, + "content": "\\[\n\\left[ \\begin{array}{c c} \\mathcal {M} _ {r} [ \\mathrm {D} _ {\\omega \\omega} ] - \\partial_ {\\omega \\omega} l _ {i ^ {\\dagger}} ^ {*} & \\partial_ {\\omega \\mathbf {x}} l _ {i ^ {\\dagger}} ^ {*} \\\\ \\partial_ {\\mathbf {x} \\omega} l _ {i ^ {\\dagger}} ^ {*} & - \\partial_ {\\mathbf {x x}} l _ {i ^ {\\dagger}} ^ {*} \\end{array} \\right] \\left[ \\begin{array}{c} \\Delta \\boldsymbol {\\omega} \\\\ \\Delta \\boldsymbol {\\alpha} \\end{array} \\right] = \\left[ \\begin{array}{c} \\mathcal {M} _ {r} [ \\nabla \\omega ] + \\nabla_ {\\omega} l _ {i ^ {\\dagger}} ^ {*} \\\\ \\mathbf {0} \\end{array} \\right],\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.103, + 0.77, + 0.471, + 0.797 + ], + "angle": 0, + "content": "where \\(\\Delta \\omega\\) is the unlearning update \\(\\mathcal{U}_r(\\omega^*, i_{r+1}^\\dagger)\\) and \\(\\Delta \\alpha\\) is an auxiliary variable that can be discarded." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.805, + 0.473, + 0.845 + ], + "angle": 0, + "content": "The linear system in Theorem 2 can be solved by conjugate gradient or fixed point methods, which are more efficient than computing the Hessian inversions (Inv-1/2) directly." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.355, + 0.869, + 0.412 + ], + "angle": 0, + "content": "Avoid Matrix Inversions (Inv-3) by Neumann Series Approximation. We expand \\(\\partial_{\\delta \\delta}^{-1}l_i^*\\) by Neumann Series: \\(\\partial_{\\delta \\delta}^{-1}l_i^* = \\lim_{k\\to \\infty}\\sum_{j = 0}^{k}\\left[\\mathbf{I} - \\partial_{\\mathbf{xx}}l_i^*\\right]^j\\). Then, clipping at order \\(k\\), we have the following approximation," + }, + { + "type": "equation", + "bbox": [ + 0.521, + 0.419, + 0.869, + 0.438 + ], + "angle": 0, + "content": "\\[\n\\partial_ {\\delta \\delta} ^ {- 1} l _ {i} ^ {*} \\approx \\mathbf {I} + \\left[ \\mathbf {I} - \\partial_ {\\delta \\delta} l _ {i} ^ {*} \\right] + \\dots + \\left[ \\mathbf {I} - \\partial_ {\\delta \\delta} l _ {i} ^ {*} \\right] ^ {k}. \\tag {15}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.444, + 0.868, + 0.472 + ], + "angle": 0, + "content": "Each term in memory \\(\\mathcal{M}_r[\\mathrm{D}_{\\omega \\omega}]\\) used in Stage I & III can be approximated by \\(\\mathrm{D}_{\\omega \\omega}l_i^* \\approx \\overline{\\mathrm{D}}_{\\omega \\omega}l_i^* :=\\)" + }, + { + "type": "equation", + "bbox": [ + 0.551, + 0.479, + 0.869, + 0.515 + ], + "angle": 0, + "content": "\\[\n\\partial_ {\\omega \\omega} l _ {i} ^ {*} - \\partial_ {\\omega \\delta} l _ {i} ^ {*} \\left(\\sum_ {j = 0} ^ {k} \\left[ \\mathbf {I} - \\partial_ {\\delta \\delta} l _ {i} ^ {*} \\right] ^ {j}\\right) \\partial_ {\\delta \\omega} l _ {i} ^ {*}. \\tag {16}\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.523, + 0.625, + 0.538 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.544, + 0.869, + 0.611 + ], + "angle": 0, + "content": "We conduct experimental evaluations on two groups of machine learning models and four common datasets, under two typical experiment settings in the unlearning literature [21-23, 26]. Our source code, experiment details, and more experiment results can be found in Supplement." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.617, + 0.667, + 0.631 + ], + "angle": 0, + "content": "5.1. Experiment Setup" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.637, + 0.687, + 0.649 + ], + "angle": 0, + "content": "5.1.1 Models and Datasets" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.66, + 0.869, + 0.713 + ], + "angle": 0, + "content": "Linear Models. We consider two linear models: 1) Ridge Regression (RR) with least square loss; 2) Logistic Regression (LR) with logistic loss, both are regularized by squared \\(\\ell_2\\)-norm with hyperparameter \\(\\lambda = 1e - 4\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.714, + 0.87, + 0.845 + ], + "angle": 0, + "content": "Neural Network Models. We utilize the Wide ResNet model (i.e., Wide ResNet 28-10 model) [63] and consider the pretraining setting [22, 26] (also similar to the mixed-privacy removal setting [21]) for the neural network model as follows. We first pretrain a model on a core dataset with adversarial training. We then finetune the model on another target dataset with adversarial finetuning [28], where all layers are frozen except the last layer. We consider unlearning requests from only the target dataset used for the adversarial finetuning." + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.876, + 0.501, + 0.887 + ], + "angle": 0, + "content": "4897" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.102, + 0.149, + 0.474, + 0.241 + ], + "angle": 0, + "content": "Adversarial Training/Finetuning Algorithms. For outer-level, we utilize SGD to optimize the model parameters \\(\\omega^{*}\\); for inner-level, we utilize both PGD [39] and FGSM [24] to generate adversarial perturbations. The experiment results by PGD are reported in the paper, while the results by FGSM and more detailed training and finetuning settings are relegated to Appendix A.1 and A.3." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.244, + 0.474, + 0.362 + ], + "angle": 0, + "content": "Datasets. We consider four common datasets for the two settings above: (linear models) i) MNIST-\\(\\mathbf{b}\\) is the subset from MNIST with classes '1' and '7' for binary classification purpose; ii) Covtype is a dataset from the LIBSVM repository [10]; (neural network model with pretraining) iii) CIFAR-10 (target dataset) and the Downsampled ImageNet (core dataset) are both natural image datasets; iv) Lacuna-10 (target dataset) and Lacuna-100 (core dataset) are both face datasets. More detail can be found in Appendix A.2." + }, + { + "type": "title", + "bbox": [ + 0.103, + 0.378, + 0.347, + 0.392 + ], + "angle": 0, + "content": "5.1.2 Baseline Unlearning Methods" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.399, + 0.475, + 0.65 + ], + "angle": 0, + "content": "We compare MUt er with six approximate unlearning methods (with their abbreviations in bold), all of which are originally designed for unlearning from standard training models. Since they utilize different Hessian terms in the unlearning update, for a fair comparison, we evaluate them under the same three-stage framework as MUt er but substitute in their corresponding unlearning update formulations. (1) Newton unlearning [26] and (2) Newton unlearning measured with adversarial perturbation (Newton-delta): both methods utilize the Newton step as the unlearning update, where the former computes at the original samples (i.e., \\(\\left[\\sum_{i = 1,i\\neq i\\dagger}^{n}\\partial_{\\omega \\omega}l(\\boldsymbol{\\omega}^{*},\\mathbf{x}_{i})\\right]^{-1}\\nabla_{\\omega}l(\\boldsymbol{\\omega}^{*},\\mathbf{x}_{i\\dagger})\\) and the latter at the adversarially perturbed samples (i.e., \\(\\left[\\sum_{i = 1,i\\neq i\\dagger}^{n}\\partial_{\\omega \\omega}l(\\boldsymbol{\\omega}^{*},\\mathbf{x}_{i} + \\boldsymbol{\\delta}_{i}^{*})\\right]^{-1}\\nabla_{\\omega}l(\\boldsymbol{\\omega}^{*},\\mathbf{x}_{i\\dagger} + \\boldsymbol{\\delta}_{i\\dagger}^{*})\\)). Similarly, we have (3) Fisher unlearning [22] and (4) Fisher-delta, which utilize the Fisher matrix \\((\\nabla_{\\omega}l\\cdot \\nabla_{\\omega}^{\\top}l)\\) to approximate the direct Hessian \\(\\partial_{\\omega \\omega}l\\). (5) Influence function-based unlearning [32, 40] and (6) Influence-delta, which utilize the influence function for STM for the unlearning update." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.65, + 0.474, + 0.704 + ], + "angle": 0, + "content": "Meanwhile, we utilize (7) Retrain-from-scratch as the golden standard reference, which applies the same adversarial training/finetuning algorithms to retrain/re-finetune the model on the remaining data to obtain \\(\\omega_{-i\\dagger}^{*}\\) in eq.(3)." + }, + { + "type": "title", + "bbox": [ + 0.103, + 0.719, + 0.281, + 0.732 + ], + "angle": 0, + "content": "5.1.3 Evaluation Metrics" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.74, + 0.474, + 0.845 + ], + "angle": 0, + "content": "We measure four aspects of the unlearning performance: 1) Effectiveness measures the closeness of the unlearned ATM compared to the golden standard Retrain, for which we utilize the \\(\\ell_2\\)-norm difference between the model parameter vectors, i.e., \\(\\| \\boldsymbol{\\omega}^u - \\boldsymbol{\\omega}_{-i^\\dagger}^*\\|_2\\); 2) Accuracy measures the clean accuracy of the unlearned ATM, for which we utilize the accuracy on clean test samples; 3) Robustness measures the adversarial accuracy of the unlearned ATM, for which we" + }, + { + "type": "image", + "bbox": [ + 0.545, + 0.149, + 0.848, + 0.167 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.517, + 0.175, + 0.682, + 0.287 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.689, + 0.174, + 0.856, + 0.287 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.518, + 0.303, + 0.685, + 0.409 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.689, + 0.303, + 0.856, + 0.409 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.517, + 0.423, + 0.68, + 0.531 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.686, + 0.424, + 0.856, + 0.531 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.552, + 0.871, + 0.631 + ], + "angle": 0, + "content": "Figure 3: Evaluation results on Logistic Regression Model: Effectiveness (top), Accuracy (middle), and Robustness (bottom) on datasets MNIST-b (left column), Covtype (right column). Large plots have greater removal numbers: \\(1\\%\\), \\(2\\%\\), \\(\\cdots\\), \\(5\\%\\); the inside small plots have fewer removal numbers: \\(1,2,\\cdots,5\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.655, + 0.871, + 0.708 + ], + "angle": 0, + "content": "utilize the accuracy on adversarial perturbed test samples; 4) Efficiency measures the unlearning time the unlearning method takes to respond the unlearning request, for which we report CPU time." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.718, + 0.678, + 0.732 + ], + "angle": 0, + "content": "5.2. Experiment Results" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.739, + 0.726, + 0.752 + ], + "angle": 0, + "content": "5.2.1 Results with Linear Model" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.762, + 0.871, + 0.801 + ], + "angle": 0, + "content": "Figure 3 reports the experiment results with logistic regression model on the MNIST-b and Covtypes datasets. More results with ridge regression are deferred to Appendix A.3." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.805, + 0.871, + 0.846 + ], + "angle": 0, + "content": "Effectiveness. Top row of Figure 3 shows the effectiveness comparison. All compared methods have increased model parameter distance with the increasing number of unlearning" + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.877, + 0.502, + 0.887 + ], + "angle": 0, + "content": "4898" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.118, + 0.151, + 0.291, + 0.269 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.296, + 0.153, + 0.462, + 0.27 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.113, + 0.271, + 0.291, + 0.387 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.291, + 0.272, + 0.462, + 0.386 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.112, + 0.388, + 0.29, + 0.503 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.29, + 0.394, + 0.462, + 0.503 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.102, + 0.519, + 0.474, + 0.572 + ], + "angle": 0, + "content": "Figure 4: Evaluation results on Neural Network: Effectiveness (top), Accuracy (middle), and Robustness (bottom) on datasets Lacuna-10 (left column) and CIFAR-10 (right column), under removal numbers \\((1,0.4\\%, 1\\%, 2\\%, 4\\%, 8\\%)\\)." + }, + { + "type": "table", + "bbox": [ + 0.109, + 0.585, + 0.472, + 0.663 + ], + "angle": 0, + "content": "
Model TypeRemoval NumberMNIST-bCovtype
FisherF-deltaMIterRetrainFisherF-deltaMIterRetrain
LR10.0020.0020.009630.0020.0020.007192
50.0100.0120.052630.0090.0110.037194
100.0190.0210.106620.0180.0220.071194
RR10.0020.0020.009640.0020.0020.006200
50.0090.0110.057650.0110.0120.032206
100.0180.0190.097650.0190.0200.064205
" + }, + { + "type": "table_caption", + "bbox": [ + 0.102, + 0.671, + 0.472, + 0.724 + ], + "angle": 0, + "content": "Table 1: Efficiency results with linear models of logistic regression (top) and ridge regression (bottom): The unlearning time (in seconds) of Fisher, Fisher-delta, MUt er and Retrain under varying removal numbers: 1, 5, 10." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.748, + 0.472, + 0.814 + ], + "angle": 0, + "content": "requests, which is due to the decreased approximation capability of the approximate unlearning criteria. MUter achieves the smallest deviation from Retrain and outperforms all the compared methods, which is because its ATM unlearning update sufficiently captures the nested data influence in ATM." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.818, + 0.473, + 0.845 + ], + "angle": 0, + "content": "Accuracy. Middle row of Figure 3 shows the clean accuracy comparison. All unlearning methods do not show a signifi" + }, + { + "type": "table", + "bbox": [ + 0.507, + 0.147, + 0.869, + 0.203 + ], + "angle": 0, + "content": "
Removal NumberLacuna-10CIFAR-10
FisherF-deltaMUtErRetrainFisherF-deltaMUtErRetrain
11.471.664.189351.511.733.815224
57.768.4121.379347.548.5818.645294
1015.5116.8241.6993215.3416.4237.575260
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.212, + 0.871, + 0.251 + ], + "angle": 0, + "content": "Table 2: Efficiency results with Neural Network: The unlearning time (in seconds) of Fisher, Fisher-delta, MUt er and Retrain under varying removal numbers: 1, 5, 10." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.275, + 0.869, + 0.314 + ], + "angle": 0, + "content": "cant drop in clean accuracy after data forgotten. In general, \\( MUtEr \\) is among the methods that achieve higher accuracy and exhibits close consistency with Retrain." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.317, + 0.869, + 0.409 + ], + "angle": 0, + "content": "Robustness. Bottom row of Figure 3 shows the robustness comparison. When the number of forgotten requests is small, most methods have little variation in perturbed accuracy. When the forgotten number becomes larger, all baseline unlearning methods have an obvious decrease in perturbed accuracy, while MUt er still shows high perturbed accuracy and has the closest proximity to Retrain." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.412, + 0.869, + 0.569 + ], + "angle": 0, + "content": "Efficiency. Table 1 shows the efficiency comparison. MUt er has significant efficiency improvement over Retrain, which is the utmost desideratum of the unlearning method. In addition, we compare with Fisher and Fisher-delta, which are the most efficient methods among the six baseline methods due to the more efficient Fisher information matrix approximation. MUt er takes more CPU time because it computes the total Hessian to obtain a more holistic data influence measure, while the baseline methods compute only the (approximate) direct Hessian and omit the indirect Hessian. Thus, the small increase in CPU time is the necessary tax to pay in exchange for more effective unlearning." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.572, + 0.87, + 0.676 + ], + "angle": 0, + "content": "Tradeoff between deletion effectiveness, accuracy, and robustness. According to the above results, there is a tradeoff between efficient and deletion effectiveness, accuracy, and robustness. That is, \\( MUtEr \\) takes slightly longer than direct Hessian-only unlearning methods due to the additional computation of the indirect Hessian. However, this extra computation is worthwhile as \\( MUtEr \\) offers improved deletion effectiveness, accuracy, and robustness." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.694, + 0.787, + 0.706 + ], + "angle": 0, + "content": "5.2.2 Results with Neural Network Model" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.715, + 0.87, + 0.844 + ], + "angle": 0, + "content": "Figure 4 summarizes the results of effectiveness, accuracy, and robustness on the two datasets for the neural network model with pretraining. MUt er has the smallest difference of parameter distance with Retrain, which indicates that MUt er generates the most similar unlearning model to the Retrain model. In addition, MUt er has the most consistent behaviour with Retrain in terms of clean accuracy and perturbation accuracy. In terms of efficiency, Table 2 reports the comparison with Retrain and two most efficient baseline methods Fisher and Fisher-delta. Similar to the linear" + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.877, + 0.502, + 0.887 + ], + "angle": 0, + "content": "4899" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.207, + 0.15, + 0.386, + 0.256 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.398, + 0.151, + 0.576, + 0.256 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.588, + 0.151, + 0.768, + 0.256 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.102, + 0.27, + 0.871, + 0.298 + ], + "angle": 0, + "content": "Figure 5: Effect of Gaussian noise injection: Effectiveness (left), Accuracy (middle), and Robustness (right) versus the standard variation \\(\\sigma\\) of Gaussian noise in log scale, under the case of removing \\(5\\%\\) samples and on the Lacuna-10 dataset." + }, + { + "type": "text", + "bbox": [ + 0.101, + 0.319, + 0.471, + 0.372 + ], + "angle": 0, + "content": "model case, MUt er has significant efficiency improvement over Retrain. Although MUt er costs more unlearning time than the approximate methods, it provides significantly more effective, more accurate, and more robust unlearned ATM." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.375, + 0.474, + 0.466 + ], + "angle": 0, + "content": "Effect of Varying Magnitudes of Gaussian Noise. Figure 5 shows the effectiveness, accuracy, and robustness comparisons under varying standard variations of Gaussian noise \\((\\sigma)\\) injected by \\(\\omega_{r + 1}^u +\\mathbf{n}\\) with \\(\\mathbf{n}\\sim \\mathcal{N}(0,\\sigma^2\\mathbf{I})\\). All methods get worse unlearning model performance with larger \\(\\sigma\\), but MUt er maintains the best performance for all \\(\\sigma\\)’s among all compared unlearning methods." + }, + { + "type": "title", + "bbox": [ + 0.103, + 0.478, + 0.216, + 0.492 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.101, + 0.499, + 0.474, + 0.655 + ], + "angle": 0, + "content": "In this paper, we studied a new joint privacy-robustness problem of machine unlearning from adversarial training models to simultaneously meet the emerging privacy regulations on Right to be Forgotten and ensure the adversarial robustness of the model. We proposed a new unlearning method called Muter, which is underpinned by a total Hessian-based measure to sufficiently capture the data influence on both model parameters and adversarial perturbations. We further introduced the Schur complement conversion and the Neumann series approximation to mitigate the computational cost. Our methods show significant enhancement in effectiveness and efficiency compared to baseline methods." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.655, + 0.472, + 0.786 + ], + "angle": 0, + "content": "As future works, several directions can be further explored: 1) extending \\( MUter \\) to other adversarial training variants like adversarial regularization; 2) further reducing the memory cost by considering low-rank/k-fact approximations to approximate the Hessian matrix, e.g., [25]; 3) studying the approximation capability of the new influence function inspired by \\( MUter \\), e.g., across different depths of neural networks [4]; 4) exploring the potential connection between the new influence function with proximal Bregman response function [2]." + }, + { + "type": "title", + "bbox": [ + 0.103, + 0.797, + 0.273, + 0.811 + ], + "angle": 0, + "content": "7. Acknowledgement" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.818, + 0.472, + 0.845 + ], + "angle": 0, + "content": "The authors would like to thank the anonymous reviewers for their constructive comments. This research has been" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.319, + 0.871, + 0.398 + ], + "angle": 0, + "content": "funded in part by National Science Foundation of China (NSFC) 62206207, 62102300, 62072395, and U20A20178, National Key Research and Development Program of China 2020AAA0107705, National Science Foundation (NSF) CNS-2124104, CNS-2125530, and National Institute of Health (NIH) R01ES033241." + }, + { + "type": "title", + "bbox": [ + 0.502, + 0.416, + 0.591, + 0.43 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.508, + 0.44, + 0.871, + 0.499 + ], + "angle": 0, + "content": "[1] Martin Abadi, Andy Chu, Ian Goodfellow, H Brendan McMahan, Ilya Mironov, Kunal Talwar, and Li Zhang. Deep learning with differential privacy. In Proceedings of the 2016 ACM SIGSAC conference on computer and communications security, 2016. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.503, + 0.87, + 0.539 + ], + "angle": 0, + "content": "[2] Juhan Bae, Nathan Ng, Alston Lo, Marzyeh Ghassemi, and Roger B. Grosse. If influence functions are the answer, then what is the question? In NeurIPS, 2022. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.542, + 0.871, + 0.602 + ], + "angle": 0, + "content": "[3] Tao Bai, Jinqi Luo, Jun Zhao, Bihan Wen, and Qian Wang. Recent advances in adversarial training for adversarial robustness. In Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence, pages 4312-4321, 8 2021. Survey Track. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.605, + 0.871, + 0.653 + ], + "angle": 0, + "content": "[4] Samyadeep Basu, Phillip Pope, and Soheil Feizi. Influence functions in deep learning are fragile. In 9th International Conference on Learning Representations, ICLR 2021, Virtual Event, Austria, May 3-7, 2021, 2021. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.656, + 0.871, + 0.704 + ], + "angle": 0, + "content": "[5] Lucas Bourtoule, Varun Chandrasekaran, Christopher A. Choquette-Choo, Hengrui Jia, Adelin Travers, Baiwu Zhang, David Lie, and Nicolas Papernot. Machine unlearning. In 42nd IEEE Symposium on Security and Privacy, 2021. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.707, + 0.871, + 0.743 + ], + "angle": 0, + "content": "[6] Jonathan Brophy and Daniel Lowd. Machine unlearning for random forests. In International Conference on Machine Learning, pages 1092-1104, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.746, + 0.871, + 0.806 + ], + "angle": 0, + "content": "[7] Qiong Cao, Li Shen, Weidi Xie, Omkar M. Parkhi, and Andrew Zisserman. Vggface2: A dataset for recognising faces across pose and age. In 2018 13th IEEE International Conference on Automatic Face Gesture Recognition (FG 2018), pages 67-74, 2018. 12" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.808, + 0.871, + 0.845 + ], + "angle": 0, + "content": "[8] Yinzhi Cao and Junfeng Yang. Towards making systems forget with machine unlearning. In 2015 IEEE Symposium on Security and Privacy, pages 463-480. IEEE, 2015. 1, 3" + }, + { + "type": "list", + "bbox": [ + 0.508, + 0.44, + 0.871, + 0.845 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.877, + 0.502, + 0.887 + ], + "angle": 0, + "content": "4900" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.112, + 0.15, + 0.471, + 0.186 + ], + "angle": 0, + "content": "[9] Nicholas Carlini and David Wagner. Towards evaluating the robustness of neural networks. In 2017 IEEE Symposium on Security and Privacy. IEEE Computer Society, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.187, + 0.472, + 0.222 + ], + "angle": 0, + "content": "[10] Chih-Chung Chang and Chih-Jen Lin. Libsvm: A library for support vector machines. ACM Trans. Intell. Syst. Technol., 2(3), may 2011. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.105, + 0.224, + 0.472, + 0.259 + ], + "angle": 0, + "content": "[11] Chong Chen, Fei Sun, Min Zhang, and Bolin Ding. Recommendation unlearning. In Proceedings of the ACM Web Conference 2022, pages 2768-2777, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.261, + 0.472, + 0.307 + ], + "angle": 0, + "content": "[12] Min Chen, Zhikun Zhang, Tianhao Wang, Michael Backes, Mathias Humbert, and Yang Zhang. Graph unlearning. In Proceedings of the ACM Conference on Computer and Communications Security 2022, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.309, + 0.471, + 0.344 + ], + "angle": 0, + "content": "[13] John M Danskin. The theory of max-min and its application to weapons allocation problems, volume 5. Springer Science & Business Media, 2012. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.346, + 0.471, + 0.393 + ], + "angle": 0, + "content": "[14] Zhun Deng, Cynthia Dwork, Jialiang Wang, and Linjun Zhang. Interpreting robust optimization via adversarial influence functions. In Proceedings of the 37th International Conference on Machine Learning, volume 119, 2020. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.395, + 0.471, + 0.43 + ], + "angle": 0, + "content": "[15] Federal Trade Commission. California company settles ftc allegations it deceived consumers about use of facial recognition in photo storage app, January 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.432, + 0.471, + 0.49 + ], + "angle": 0, + "content": "[16] Matt Fredrikson, Somesh Jha, and Thomas Ristenpart. Model inversion attacks that exploit confidence information and basic countermeasures. In Proceedings of the 22nd ACM SIGSAC conference on computer and communications security, pages 1322-1333, 2015. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.492, + 0.471, + 0.516 + ], + "angle": 0, + "content": "[17] Regulation (EU) 2016/679 of the European parliament and of the council of 27 April 2016, 2016. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.517, + 0.471, + 0.552 + ], + "angle": 0, + "content": "[18] Amirata Ghorbani and James Zou. Data shapley: Equitable valuation of data for machine learning. In International Conference on Machine Learning, pages 2242-2251, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.554, + 0.471, + 0.601 + ], + "angle": 0, + "content": "[19] Antonio A Ginart, Melody Y Guan, Gregory Valiant, and James Zou. Making ai forget you: data deletion in machine learning. In Proceedings of the 33rd International Conference on Neural Information Processing Systems, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.602, + 0.471, + 0.649 + ], + "angle": 0, + "content": "[20] Jairo Giraldo, Alvaro Cardenas, Murat Kantarcioglu, and Jonathan Katz. Adversarial classification under differential privacy. In Network and Distributed Systems Security (NDSS) Symposium 2020, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.651, + 0.471, + 0.709 + ], + "angle": 0, + "content": "[21] Aditya Golatkar, Alessandro Achille, Avinash Ravichandran, Marzia Polito, and Stefano Soatto. Mixed-privacy forgetting in deep networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 792–801, 2021. 1, 4, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.712, + 0.471, + 0.77 + ], + "angle": 0, + "content": "[22] Aditya Golatkar, Alessandro Achille, and Stefano Soatto. Eternal sunshine of the spotless net: Selective forgetting in deep networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9304-9312, 2020. 1, 3, 6, 7, 12" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.772, + 0.471, + 0.819 + ], + "angle": 0, + "content": "[23] Aditya Golatkar, Alessandro Achille, and Stefano Soatto. Forgetting outside the box: Scrubbing deep networks of information accessible from input-output observations. In European Conference on Computer Vision, 2020. 1, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.821, + 0.471, + 0.844 + ], + "angle": 0, + "content": "[24] Ian J. Goodfellow, Jonathon Shlens, and Christian Szegedy. Explaining and harnessing adversarial examples. In Yoshua" + }, + { + "type": "list", + "bbox": [ + 0.105, + 0.15, + 0.472, + 0.844 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.15, + 0.869, + 0.174 + ], + "angle": 0, + "content": "Bengio and Yann LeCun, editors, 3rd International Conference on Learning Representations, 2015. 1, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.175, + 0.869, + 0.233 + ], + "angle": 0, + "content": "[25] Roger Grosse, Juhan Bae, Cem Anil, Nelson Elhage, Alex Tamkin, Amirhossein Tajdini, Benoit Steiner, Dustin Li, Esin Durmus, Ethan Perez, et al. Studying large language model generalization with influence functions. arXiv preprint arXiv:2308.03296, 2023. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.236, + 0.868, + 0.282 + ], + "angle": 0, + "content": "[26] Chuan Guo, Tom Goldstein, Awni Y. Hannun, and Laurens van der Maaten. Certified data removal from machine learning models. In Proceedings of the 37th International Conference on Machine Learning, 2020. 1, 3, 4, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.284, + 0.868, + 0.32 + ], + "angle": 0, + "content": "[27] Jamie Hayes, Borja Balle, and M Pawan Kumar. Learning to be adversarially robust and differentially private. arXiv preprint arXiv:2201.02265, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.322, + 0.869, + 0.392 + ], + "angle": 0, + "content": "[28] Dan Hendrycks, Kimin Lee, and Mantas Mazeika. Using pre-training can improve model robustness and uncertainty. In Kamalika Chaudhuri and Ruslan Salakhutdinov, editors, Proceedings of the 36th International Conference on Machine Learning, volume 97 of Proceedings of Machine Learning Research, pages 2712-2721, 09-15 Jun 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.394, + 0.869, + 0.44 + ], + "angle": 0, + "content": "[29] Dan Hendrycks, Kimin Lee, and Mantas Mazeika. Using pre-training can improve model robustness and uncertainty. In International Conference on Machine Learning, pages 2712-2721, 2019. 12" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.443, + 0.869, + 0.478 + ], + "angle": 0, + "content": "[30] Ruitong Huang, Bing Xu, Dale Schuurmans, and Csaba Szepesvári. Learning with a strong adversary. CoRR, abs/1511.03034, 2015. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.48, + 0.868, + 0.527 + ], + "angle": 0, + "content": "[31] Zachary Izzo, Mary Anne Smart, Kamalika Chaudhuri, and James Zou. Approximate data deletion from machine learning models. In International Conference on Artificial Intelligence and Statistics, pages 2008-2016, 2021. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.529, + 0.869, + 0.563 + ], + "angle": 0, + "content": "[32] Pang Wei Koh and Percy Liang. Understanding black-box predictions via influence functions. In International Conference on Machine Learning, 2017. 5, 7, 12" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.565, + 0.869, + 0.613 + ], + "angle": 0, + "content": "[33] Haowen Lin, Jian Lou, Li Xiong, and Cyrus Shahabi. Integer-arithmetic-only certified robustness for quantized neural networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7828-7837, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.614, + 0.869, + 0.673 + ], + "angle": 0, + "content": "[34] Shen Lin, Xiaoyu Zhang, Chenyang Chen, Xiaofeng Chen, and Willy Susilo. Erm-ktp: Knowledge-level machine unlearning via knowledge transfer. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.675, + 0.869, + 0.72 + ], + "angle": 0, + "content": "[35] Junxu Liu, Jian Lou, Li Xiong, Jinfei Liu, and Xiaofeng Meng. Projected federated averaging with heterogeneous differential privacy. Proceedings of the VLDB Endowment, 15(4):828-840, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.723, + 0.869, + 0.77 + ], + "angle": 0, + "content": "[36] Yang Liu, Mingyuan Fan, Cen Chen, Ximeng Liu, Zhuo Ma, Li Wang, and Jianfeng Ma. Backdoor defense with machine unlearning. In IEEE INFOCOM 2022 - IEEE Conference on Computer Communications, page 280-289, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.772, + 0.869, + 0.819 + ], + "angle": 0, + "content": "[37] Jian Lou and Yiu-ming Cheung. An uplink communication-efficient approach to featurewise distributed sparse optimization with differential privacy. IEEE Transactions on Neural Networks and Learning Systems, 32(10):4529-4543, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.821, + 0.869, + 0.844 + ], + "angle": 0, + "content": "[38] Jie Ma, Xiangyuan Lan, Bineng Zhong, Guorong Li, Zhenjun Tang, Xianxian Li, and Rongrong Ji. Robust tracking via" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.15, + 0.869, + 0.844 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.877, + 0.5, + 0.887 + ], + "angle": 0, + "content": "4901" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.135, + 0.15, + 0.473, + 0.185 + ], + "angle": 0, + "content": "uncertainty-aware semantic consistency. IEEE Transactions on Circuits and Systems for Video Technology, 33(4):1740-1751, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.187, + 0.472, + 0.234 + ], + "angle": 0, + "content": "[39] Aleksander Madry, Aleksandar Makelov, Ludwig Schmidt, Dimitris Tsipras, and Adrian Vladu. Towards deep learning models resistant to adversarial attacks. In 6th International Conference on Learning Representations, 2018. 1, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.105, + 0.236, + 0.472, + 0.271 + ], + "angle": 0, + "content": "[40] Ananth Mahadevan and Michael Mathioudakis. Certifiable machine unlearning for linear models. arXiv preprint arXiv:2106.15093, 2021. 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.272, + 0.472, + 0.32 + ], + "angle": 0, + "content": "[41] Neil G Marchant, Benjamin IP Rubinstein, and Scott Alfeld. Hard to forget: Poisoning attacks on certified machine unlearning. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 7691-7700, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.321, + 0.472, + 0.369 + ], + "angle": 0, + "content": "[42] Brendan McMahan, Eider Moore, Daniel Ramage, Seth Hampson, and Blaise Aguera y Arcas. Communication-efficient learning of deep networks from decentralized data. In Artificial intelligence and statistics, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.37, + 0.472, + 0.428 + ], + "angle": 0, + "content": "[43] Ronak Mehta, Sourav Pal, Vikas Singh, and Sathya N. Ravi. Deep unlearning via randomized conditionally independent hessian. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 10422-10431, June 2022. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.43, + 0.472, + 0.466 + ], + "angle": 0, + "content": "[44] Seth Neel, Aaron Roth, and Saeed Sharifi-Malvajerdi. Descent-to-delete: Gradient-based methods for machine unlearning. In Algorithmic Learning Theory, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.468, + 0.472, + 0.515 + ], + "angle": 0, + "content": "[45] Nicolas Papernot, Patrick McDaniel, Arunesh Sinha, and Michael P Wellman. Sok: Security and privacy in machine learning. In 2018 IEEE European Symposium on Security and Privacy (EuroS&P), pages 399-414. IEEE, 2018. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.517, + 0.472, + 0.551 + ], + "angle": 0, + "content": "[46] Jian Pei. A survey on data pricing: from economics to data science. IEEE Transactions on knowledge and Data Engineering, 2020. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.553, + 0.472, + 0.6 + ], + "angle": 0, + "content": "[47] Hai Phan, My T Thai, Han Hu, Ruoming Jin, Tong Sun, and Dejing Dou. Scalable differential privacy with certified robustness in adversarial learning. In International Conference on Machine Learning, pages 7683-7694, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.601, + 0.472, + 0.673 + ], + "angle": 0, + "content": "[48] NhatHai Phan, Minh N. Vu, Yang Liu, Ruoming Jin, Dejing Dou, Xintao Wu, and My T. Thai. Heterogeneous gaussian mechanism: Preserving differential privacy in deep learning with provable robustness. In Sarit Kraus, editor, Proceedings of the Twenty-Eighth International Joint Conference on Artificial Intelligence, pages 4753-4759, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.674, + 0.472, + 0.721 + ], + "angle": 0, + "content": "[49] Ayush Sekhari, Jayadev Acharya, Gautam Kamath, and Ananda Theertha Suresh. Remember what you want to forget: Algorithms for machine unlearning. Advances in Neural Information Processing Systems, 34:18075-18086, 2021. 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.722, + 0.472, + 0.77 + ], + "angle": 0, + "content": "[50] Uri Shaham, Yutaro Yamada, and Sahand Negahban. Understanding adversarial training: Increasing local stability of supervised models through robust optimization. Neurocomputing, 307:195-204, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.772, + 0.472, + 0.819 + ], + "angle": 0, + "content": "[51] Reza Shokri, Marco Stronati, Congzheng Song, and Vitaly Shmatikov. Membership inference attacks against machine learning models. In 2017 IEEE Symposium on Security and Privacy, pages 3-18. IEEE, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.82, + 0.472, + 0.844 + ], + "angle": 0, + "content": "[52] Liwei Song, Reza Shokri, and Prateek Mittal. Privacy risks of securing machine learning models against adversarial exam" + }, + { + "type": "list", + "bbox": [ + 0.105, + 0.15, + 0.473, + 0.844 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.15, + 0.868, + 0.173 + ], + "angle": 0, + "content": "plies. In Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.175, + 0.869, + 0.234 + ], + "angle": 0, + "content": "[53] Qiheng Sun, Xiang Li, Jiayao Zhang, Li Xiong, Weiran Liu, Jinfei Liu, Zhan Qin, and Kui Ren. Shapleyfl: Robust federated learning based on shapley value. In Proceedings of the 29th ACM SIGKDD Conference on Knowledge Discovery and Data Mining, pages 2096-2108, 2023. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.235, + 0.869, + 0.292 + ], + "angle": 0, + "content": "[54] Christian Szegedy, Wojciech Zaremba, Ilya Sutskever, Joan Bruna, Dumitru Erhan, Ian J. Goodfellow, and Rob Fergus. Intriguing properties of neural networks. In Yoshua Bengio and Yann LeCun, editors, 2nd International Conference on Learning Representations, 2014. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.293, + 0.869, + 0.34 + ], + "angle": 0, + "content": "[55] Farnaz Tahmasebian, Jian Lou, and Li Xiong. Robustfed: a truth inference approach for robust federated learning. In Proceedings of the 31st ACM International Conference on Information & Knowledge Management, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.341, + 0.869, + 0.388 + ], + "angle": 0, + "content": "[56] Pengfei Tang, Wenjie Wang, Jian Lou, and Li Xiong. Generating adversarial examples with distance constrained adversarial imitation networks. IEEE Transactions on Dependable and Secure Computing, 19(6):4145-4155, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.389, + 0.869, + 0.446 + ], + "angle": 0, + "content": "[57] Anvith Thudi, Gabriel Deza, Varun Chandrasekaran, and Nicolas Papernot. Unrolling sgd: Understanding factors influencing machine unlearning. In 2022 IEEE 7th European Symposium on Security and Privacy (EuroS&P), pages 303-319. IEEE, 2022. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.448, + 0.869, + 0.495 + ], + "angle": 0, + "content": "[58] Anvith Thudi, Hengrui Jia, Ilia Shumailov, and Nicolas Papernot. On the necessity of auditable algorithmic definitions for machine unlearning. In 31st USENIX Security Symposium (USENIX Security 22), pages 4007-4022, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.496, + 0.869, + 0.543 + ], + "angle": 0, + "content": "[59] Boxi Wu, Jindong Gu, Zhifeng Li, Deng Cai, Xiaofei He, and Wei Liu. Towards efficient adversarial training on vision transformers. In European Conference on Computer Vision, pages 307-325, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.544, + 0.869, + 0.579 + ], + "angle": 0, + "content": "[60] Yinjun Wu, Edgar Dobriban, and Susan Davidson. Deltagrad: Rapid retraining of machine learning models. In International Conference on Machine Learning, 2020. 1, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.58, + 0.869, + 0.626 + ], + "angle": 0, + "content": "[61] Jingwen Ye, Yifang Fu, Jie Song, Xingyi Yang, Songhua Liu, Xin Jin, Mingli Song, and Xinchao Wang. Learning with recoverable forgetting. In European Conference on Computer Vision, pages 87-103, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.627, + 0.869, + 0.673 + ], + "angle": 0, + "content": "[62] Xiaoyong Yuan, Pan He, Qile Zhu, and Xiaolin Li. Adversarial examples: Attacks and defenses for deep learning. IEEE transactions on neural networks and learning systems, 30(9):2805-2824, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.674, + 0.869, + 0.697 + ], + "angle": 0, + "content": "[63] Sergey Zagoruyko and Nikos Komodakis. Wide residual networks. In British Machine Vision Conference, 2016. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.698, + 0.869, + 0.733 + ], + "angle": 0, + "content": "[64] Guojun Zhang, Kaiwen Wu, Pascal Poupart, and Yaoliang Yu. Newton-type methods for minimax optimization. arXiv preprint arXiv:2006.14592, 2020. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.734, + 0.869, + 0.78 + ], + "angle": 0, + "content": "[65] Peng-Fei Zhang, Guangdong Bai, Zi Huang, and Xin-Shun Xu. Machine unlearning for image retrieval: A generative scrubbing approach. In Proceedings of the 30th ACM International Conference on Multimedia, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.781, + 0.869, + 0.841 + ], + "angle": 0, + "content": "[66] Xiaoyu Zhang, Yulin Jin, Tao Wang, Jian Lou, and Xiaofeng Chen. Purifier: Plug-and-play backdoor mitigation for pretrained models via anomaly activation suppression. In Proceedings of the 30th ACM International Conference on Multimedia, pages 4291-4299, 2022. 1" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.15, + 0.869, + 0.841 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.877, + 0.501, + 0.887 + ], + "angle": 0, + "content": "4902" + } + ] +] \ No newline at end of file diff --git a/2023/MUter_ Machine Unlearning on Adversarially Trained Models/794014c8-e2b9-40ef-b0f6-0010a00c9a4d_origin.pdf b/2023/MUter_ Machine Unlearning on Adversarially Trained Models/794014c8-e2b9-40ef-b0f6-0010a00c9a4d_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..dbd2ab0778162af6ff1d34782751a66cf7818b13 --- /dev/null +++ b/2023/MUter_ Machine Unlearning on Adversarially Trained Models/794014c8-e2b9-40ef-b0f6-0010a00c9a4d_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:4a813de745c69048ae1295d034f91b90ec7103144909de3e280a4c9f0804e669 +size 1603212 diff --git a/2023/MUter_ Machine Unlearning on Adversarially Trained Models/full.md b/2023/MUter_ Machine Unlearning on Adversarially Trained Models/full.md new file mode 100644 index 0000000000000000000000000000000000000000..4180aabd2cc43c88b13c4e30173821e00b767f3e --- /dev/null +++ b/2023/MUter_ Machine Unlearning on Adversarially Trained Models/full.md @@ -0,0 +1,429 @@ +# MUt er: Machine Unlearning on Adversarily Trained Models + +Junxu Liu $^{1,*}$ , Mingsheng Xue $^{2,*}$ , Jian Lou $^{3,6,\dagger}$ , Xiaoyu Zhang $^{4}$ , Li Xiong $^{5}$ , Zhan Qin $^{3,6}$ + +1Renmin University of China 2Guangzhou Institute of Technology, Xidian University 3Zhejiang University 4Xidian University 5Emory University 6ZJU-Hangzhou Global Scientific and Technological Innovation Center + +junxu_liu@ruc.edu.cn xuemingsheng@stu.xidian.edu.cn jian.lou@zju.edu.cn + +xiaoyuzhang@xidian.edu.cn lxiong@emory.edu qinzhan@zju.edu.cn + +# Abstract + +Machine unlearning is an emerging task of removing the influence of selected training datapoints from a trained model upon data deletion requests, which echoes the widely enforced data regulations mandating the Right to be Forgotten. Many unlearning methods have been proposed recently, achieving significant efficiency gains over the naive baseline of retraining from scratch. However, existing methods focus exclusively on unlearning from standard training models and do not apply to adversarial training models (ATMs) despite their popularity as effective defenses against adversarial examples. During adversarial training, the training data are involved in not only an outer loop for minimizing the training loss, but also an inner loop for generating the adversarial perturbation. Such bi-level optimization greatly complicates the influence measure for the data to be deleted and renders the unlearning more challenging than standard model training with single-level optimization. This paper proposes a new approach called MUt er for unlearning from ATMs. We derive a closed-form unlearning step underpinned by a total Hessian-related data influence measure, while existing methods can mis-capture the data influence associated with the indirect Hessian part. We further alleviate the computational cost by introducing a series of approximations and conversions to avoid the most computationally demanding parts of Hessian inversions. The efficiency and effectiveness of MUt er have been validated through experiments on four datasets using both linear and neural network models. + +# 1. Introduction + +Machine learning (ML) models are increasingly applied to a broad range of applications, accompanied by growing concerns about their privacy and robustness issues. Both issues are actively studied in recent years [45]. On the + +privacy side, model inversion attack [16] and membership inference attack [51] reveal that the trained ML model contains sensitive information of its training data, which can cause privacy loss for individuals contributing their data for model training. On the robustness side, adversarial example attack is one of the most well-recognized robustness attacks [24, 30, 39, 62]. It can easily fool an undefended model, e.g., standard training model (STM), to misclassify by a small adversarial perturbation on the input [9, 24, 39]. Many works focus either on the privacy [1, 35, 37, 42, 51] or on the robustness aspect [9, 33, 38, 53–56, 66], few works studied both. Yet, it is critical to consider privacy and robustness jointly [20, 27, 36, 41, 47, 48, 52] to build ML models to simultaneously meet data privacy regulations and ensure robustness against adversarial threats. + +In this paper, we target a new joint privacy-robustness problem to simultaneously meet emerging privacy regulations and ensure adversarial robustness of the model, which has not been examined before: how to efficiently and effectively remove the influence of a training datapoint from an adversarially trained model upon data deletion request? + +The privacy need is driven by the widely enacted user data regulations that enforce the Right to be Forgotten, for example, the European Union's GDPR [17], the California Consumer Privacy Act (CCPA), and Canada's proposed Consumer Privacy Protection Act (CPPA). These regulations mandate the deletion of personal data upon user requests and can even include the deletion of models and algorithms derived from the user data, e.g., the Federal Trade Commission [15]. Machine unlearning [5,8] aims to obtain an updated model with the influence of the target datapoint removed in an effective and efficient way. That is, the updated model should be similar to the model obtained by the computationally expensive retraining-from-scratch approach, while consuming less computation [21-23,26,31,43,44,58,60,61,65]. + +The robustness is achieved by the adversarial training model (ATM) [3, 24, 30, 39, 59], which is a popular and effective defense for enhancing the model robustness against adversarial examples by creating and incorporating adver + +![](images/6a501db60794b36cfe20ab0dcdd885488c378fbbfc9395fcfe13273a8ad874fc.jpg) +Figure 1: ATM has two interdependent sets of optimization variables, model parameters and adversarial perturbations (yellow arrows), both of which contain nested training data influence (blue arrows). To remove such nested data influence, ATM unlearning requires the total Hessian that consists of both direct and indirect Hessian components (green solid lines). Existing unlearning methods designed for standard training models are inapplicable to ATM unlearning, because they only use direct Hessian information during the unlearning update and do not capture sufficient data influence (red dashed lines). + +sarial examples into the training process. ATM is trained by a bi-level optimization with the model parameters as the outer-level variable and the adversarial perturbations as the inner-level variable. To the best of our knowledge, all existing unlearning methods focus solely on data removal from STM. As our analysis will reveal in Section 3, the existing methods cannot be applied to ATM unlearning without miscapturing the data influence to be removed, due to ATM's bi-level optimization structure. + +In this paper, we propose a new unlearning approach called MUt e r: M Machine Unlearning for data removal from adversarial training models. First, we define the ATM unlearning task in accordance with the mainstream machine unlearning standard. Second, we convert it to an ATM unlearning criteria derived from the optimality condition of ATM, which facilitates the derivation of the unlearning update for ATM. Meanwhile, existing unlearning methods designed for STM cannot satisfy the ATM unlearning criteria. As illustrated in Figure 1, ATM, as a bi-level optimization, has two sets of variables: model parameters and adversarial perturbations, which are interdependent and both contain training data information. In contrast, STM, as a single-level optimization, has only one set of variables: model parameters, which have a direct influence dependence on each training datapoint. Existing unlearning methods cannot sufficiently remove data influence from ATM because they fail to account for the indirect influence on the model parameters (i.e., miss the indirect Hessian part in Figure 1). That is, due to the coupled outer-inner optimization, any updates to the outer model parameters will incur further updates for both the adversarial perturbations and the model parameters. To address this, we derive a new closed-form unlearning update for ATM, which is underpinned by the total Hessian-based + +influence measure. Third, based on the ATM unlearning update, we propose a three-stage unlearning framework to support successive unlearning requests for ATM, which enhances efficiency by selectively storing certain computations in memory. Last, we leverage Schur complement conversion and Neumann series approximation to avoid the computationally demanding and numerical unstable computations of Hessian matrix and its inversions. + +To summarize, our main contributions are: + +1. We introduce the problem of unlearning from adversarial training models, which is a new and pressing challenge to simultaneously meet emerging privacy regulations and ensure the adversarial robustness of the model. To the best of our knowledge, it has not been studied in the existing literature. +2. We derive a new unlearning update tailored to ATM unlearning, which has the total Hessian-based data influence measure to sufficiently account for the interdependence between inner and outer optimizations of ATM. +3. We propose MUt er based on the proposed unlearning update, which supports successive unlearning requests for ATM and introduces a series of conversions and approximations for Hessian inversions to alleviate the computational cost and improve the numerical stability. +4. We perform a comprehensive evaluation to verify that $MUter$ achieves effective and efficient unlearning performance while maintaining the model accuracy and adversarial robustness, under two unlearning settings on four datasets. + +# 2. Preliminaries and Related Work + +# 2.1. Setup and Notation + +Setup. Denote the training dataset with $n$ training samples by $\mathcal{D} = \{(\mathbf{x}_1,y_1),\ldots ,(\mathbf{x}_n,y_n)\}$ , where for $\forall i\in$ + +$\{1,\dots ,n\}$ $\mathbf{x}_i\in \mathbb{R}^d$ is the $d$ -dimensional feature vector, and $y_{i}\in \mathbb{R}$ is the corresponding response/label. Denote the loss function by $l(\omega ,\mathbf{x}_i)$ , where $\omega \in \mathbb{R}^p$ represents the vector of the $p$ -dimensional model parameters. + +Standard Training Model (STM). Standard training model refers to the empirical risk minimization model: $\omega_{std}^{*} = \mathrm{argmin}_{\omega}\frac{1}{n}\sum_{i = 1}^{n}l(\omega ,\mathbf{x}_i)$ , where $\omega \in \mathbb{R}^p$ is the model parameter variable. + +Adversarial Training Model (ATM). Adversarial training model is an effective defense against robustness threats posed by the adversarial attack. In this paper, we adopt one of the most widely-used ATM variants to consider the following bi-level robust optimization formulation [30, 50], + +$$ +\boldsymbol {\omega} ^ {*} = \underset {\boldsymbol {\omega}} {\operatorname {a r g m i n}} \frac {1}{n} \sum_ {i = 1} ^ {n} \max _ {\delta_ {i} \in \mathcal {B} (\mathbf {x} _ {i}, r)} l (\boldsymbol {\omega}, \mathbf {x} _ {i} + \boldsymbol {\delta} _ {i}), \tag {1} +$$ + +where the inner optimization is to find adversarial perturbation $\delta_{i}$ from the constraint set $\mathcal{B}(\mathbf{x}_i,r)$ to maximize the loss and the outer optimization is to find the model parameter $\omega$ that minimizes the loss for the adversarially perturbed examples. To make the interdependence between the outer variable $\omega$ and the inner variable $\delta$ more explicit, we further introduce an auxiliary function $\delta_{i}(\omega)$ given by + +$$ +\delta_ {i} (\boldsymbol {\omega}) = \underset {\boldsymbol {\delta} _ {i} \in \mathcal {B} (\mathbf {x} _ {i}, r)} {\operatorname {a r g m a x}} l \left(\boldsymbol {\omega}, \mathbf {x} _ {i} + \boldsymbol {\delta} _ {i}\right). \tag {2} +$$ + +Machine Unlearning for Adversarial Training Models. Definition 1 below specifies the ATM unlearning task in consistency with the mainstream unlearning standard. For notational simplicity, we focus on single-point removal in the paper, but the analysis and algorithms developed in the paper are generalizable to batch removal as well (please refer to Appendix B.5 for the batch removal generalization). + +Definition 1. (Machine Unlearning for Adversarial Training Models) For a trained adversarial training model as in eq.(1), let $\forall i^{\dagger}\in \{1,\dots ,n\}$ be the index of a datapoint to be forgotten. The ATM after machine unlearning unlearning (forgetting datapoint $i^{\dagger}$ ) has parameter $\omega_{-i^{\dagger}}^{*}$ as follows, + +$$ +\omega_ {- i ^ {\dagger}} ^ {*} = \underset {\omega} {\operatorname {a r g m i n}} \frac {1}{n - 1} \sum_ {i = 1, i \neq i ^ {\dagger}} ^ {n} \max _ {\delta_ {i} \in \mathcal {B} (\mathbf {x} _ {i}, r)} l (\omega , \mathbf {x} _ {i} + \delta_ {i}). \tag {3} +$$ + +Retraining-from-scratch serves as the golden standard and also a naive baseline to obtain the unlearned ATM $\omega_{-i\dagger}^{*}$ , which is prohibitive in computation, especially for ATM with both inner maximization and outer minimization. Hence, the goal of machine unlearning for ATM is to approximately remove $i^{\dagger}$ 's influence with great computational efficiency improvement over retraining-from-scratch. + +Notation. For a twice differentiable $l(\omega, \mathbf{x} + \delta)$ , $\nabla_{\omega} l(\omega, \mathbf{x} + \delta)$ denotes the direct gradient of $l$ with respect to (w.r.t.) $\omega$ and $\partial_{\omega \omega} l(\omega, \mathbf{x} + \delta)$ , $\partial_{\omega \delta} l(\omega, \mathbf{x} + \delta)$ , $\partial_{\delta \omega} l(\omega, \mathbf{x} + \delta)$ , + +$\partial_{\delta \delta}l(\omega ,\mathbf{x} + \delta)$ denote the second order partial derivatives w.r.t. $\omega$ and $\delta$ , correspondingly. The total Hessian is + +$$ +\mathrm {D} _ {\omega \omega} l (\omega , \mathbf {x} + \delta) := \overbrace {\partial_ {\omega \omega} l (\omega , \mathbf {x} + \delta)} ^ {\text {D i r e c t H e s s i a n}} - \overbrace {\partial_ {\omega \delta} \partial_ {\delta \delta} ^ {- 1} \partial_ {\delta \omega} l (\omega , \mathbf {x} + \delta)} ^ {\text {I n d i r e c t H e s s i a n}}, \tag {4} +$$ + +where $\partial_{\omega \delta}\partial_{\delta \delta}^{-1}\partial_{\delta \omega}l(\omega ,\mathbf{x} + \boldsymbol {\delta}) = \partial_{\omega \delta}l(\omega ,\mathbf{x} + \boldsymbol {\delta})(\partial_{\delta \delta}l(\omega ,\mathbf{x} + \boldsymbol {\delta}))^{-1}\partial_{\delta \omega}l(\omega ,\mathbf{x} + \boldsymbol {\delta})$ .We also use the short hand notation $l_i^*\coloneqq l(\pmb {\omega}^*,\mathbf{x}_i + \delta_i(\pmb {\omega}^*))$ and similarly introduce $\nabla_{\omega}l_{i}^{*},\partial_{\omega \omega}l_{i}^{*},\partial_{\omega \delta}l_{i}^{*},\partial_{\delta \omega}l_{i}^{*},\partial_{\delta \delta}l_{i}^{*}$ + +# 2.2. Related Work + +We briefly review existing machine unlearning methods. They are exclusively focused on STM and are not applicable to ATM unlearning with sufficient data influence removal. We provide a brief overview of current machine unlearning methods, which are focused exclusively on unlearning for STM and are not applicable to ATM unlearning with sufficient data influence removal. Thus, it is necessary to develop a new unlearning approach specific to ATM unlearning. + +Exact Machine Unlearning. Exact unlearning methods perform exact retraining but manage to do so only on a selective portion of the dataset to avoid retraining on the entire dataset. Some exact unlearning methods are designed for specific models like Naive Bayes [8], quantized k-means [19], and random forests [6]. Recently, SISA [5] proposes a more general exact unlearning strategy. It divides the training data into multiple disjoint shards during the training phase, and retransmits only on the shard that contains the data to be removed during the unlearning phase. Later, [11] and [12] extend the SISA strategy to unlearning for recommendation systems and graph neural networks. However, the SISA strategy requires different shards to be independently updatable from each other, which is not the case for ATM due to its interdependent bi-level structure. + +Approximate Machine Unlearning. Approximate unlearning methods seek the updated model parameters to approximately satisfy the optimality condition of the objective function on the remaining data, which can be roughly divided into three categories. 1) Unlearning with direct Hessian-related terms: [22, 26, 31, 34, 40, 43, 49] propose Newton step-based unlearning updates, where the Newton curvature matrices are direct Hessian-related terms. These methods also inject Gaussian noise to further destroy the remaining data influence due to the discrepancy between the exact unlearning standard and the approximate unlearning criteria. Some works also consider to alleviate the computational cost of the Hessian. For example, [22] proposes to approximate the direct Hessian with Fisher information matrix; [43] proposes to avoid dealing with the entire direct Hessian by selecting small Hessian blocks for unlearning update. 2) Unlearning based on neural tangent kernel (NTK) theory: they approximates the training phase by NTK theory, where [23] regards + +the training as an approximately linear change and [21] divides the training phase into two stages, one is the linear standard training on the core dataset, and the other is the linear finetuning on the target dataset. Both works then apply direct Hessian-related unlearning updates. 3) Unlearning by tracking the Stochastic Gradient Descent (SGD) path during training: DeltaGrad [60] and unrollSGD [57] propose to track and reverse the SGD optimization path during the training phase. However, all above methods do not consider the interdependence between model parameters and adversarial perturbations of ATM, which cannot holistically capture the data influence, as will be detailed in the next section. + +# 3. Unlearning Update for ATM + +ATM Unlearning Criteria. We begin by converting eq.(3) in Definition 1 to the optimality condition form of ATM based on Danskin's Theorem [13], + +$$ +\sum_ {i = 1, i \neq i ^ {\dagger}} ^ {n} \nabla_ {\omega} l \left(\omega_ {- i ^ {\dagger}} ^ {*}, \mathbf {x} _ {i} + \delta_ {i} \left(\omega_ {- i ^ {\dagger}} ^ {*}\right)\right) = 0, \tag {5} +$$ + +which provides more convenience to the follow-up ATM unlearning designs. Our goal is to find a closed-form unlearning update $\mathcal{U}(\boldsymbol{\omega}^*, i^\dagger)$ such that the unlearning model with parameter $\boldsymbol{\omega}^u = \boldsymbol{\omega}^* + \mathcal{U}(\boldsymbol{\omega}^*, i^\dagger)$ will satisfy the following ATM unlearning criteria, + +$$ +\sum_ {i = 1, i \neq i ^ {\dagger}} ^ {n} \nabla_ {\omega} l \left(\omega^ {u}, \mathbf {x} _ {i} + \delta_ {i} \left(\omega^ {u}\right)\right) \approx 0. \tag {6} +$$ + +Cause of Inapplicability of Existing Approximate Unlearning Methods. Before deriving our ATM unlearning update, we recall the design rationale common to existing approximate machine unlearning methods and point out why they fail to sufficiently remove the data influence for ATM. Despite the varying forms of specific unlearning updates, existing approximate unlearning methods all exploit the trained model parameter $\omega^{*}$ and connect it with the unlearned model $\omega^{u}$ by first-order expansion of $\nabla_{\omega}l$ around $\omega^{*}$ : + +$$ +\begin{array}{l} \frac {1}{n - 1} \sum_ {i = 1, i \neq i ^ {\dagger}} ^ {n} \nabla_ {\omega} l \left(\omega^ {u}, \mathbf {x} _ {i} + \delta_ {i} \left(\omega^ {u}\right)\right) \\ \approx \frac {1}{n - 1} \sum_ {i = 1, i \neq i ^ {\dagger}} ^ {n} \left[ \nabla_ {\omega} l \left(\omega^ {*}, \mathbf {x} _ {i} + \delta_ {i} \left(\omega^ {u}\right)\right) \right. \tag {7} \\ \left. + \partial_ {\omega} \omega l \left(\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i} + \delta_ {i} \left(\boldsymbol {\omega} ^ {u}\right)\right) \left(\boldsymbol {\omega} ^ {u} - \boldsymbol {\omega} ^ {*}\right) \right]. \\ \end{array} +$$ + +Existing methods then obtain the updated $\omega^u$ by letting the right hand side of eq.(7) approach 0 and exploiting the optimality condition of $\omega^{*}$ . For example, the influence function-inspired unlearning [26, 49] has $\mathbf{u}(\boldsymbol{\omega}^{*}, i^{\dagger}) =$ + +$$ +\left[ \sum_ {i = 1, i \neq i ^ {\dagger}} ^ {n} \underbrace {\partial_ {\omega \omega} l \left(\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i} + \delta_ {i} \left(\boldsymbol {\omega} ^ {u}\right)\right)} _ {\text {D i r e c t H e s s i a n - o n l y}} \right] ^ {- 1} \nabla_ {\omega} l \left(\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i ^ {\dagger}} + \delta_ {i ^ {\dagger}} \left(\boldsymbol {\omega} ^ {u}\right)\right). \tag {8} +$$ + +However, there are two obvious issues when applying the above design rationale to the ATM unlearning: 1) the conversion from eq.(7) to eq.(8) requires $\sum_{i=1}^{n} \nabla_{\omega} l(\omega^{*}, \mathbf{x}_{i} + \delta_{i}(\omega^{u})) = 0$ , which does not hold in general. Rather, the optimality condition only promises $\sum_{i=1}^{n} \nabla_{\omega} l(\omega^{*}, \mathbf{x}_{i} + \delta_{i}(\omega^{*})) = 0$ ; 2) the Hessian $\partial_{\omega \omega} l(\omega^{*}, \mathbf{x}_{i} + \delta_{i}(\omega^{u}))$ and gradient $\nabla_{\omega} l(\omega^{*}, \mathbf{x}_{i} + \delta_{i}(\omega^{u}))$ in eq.(8) are not commutable without knowing $\omega^{u}$ in advance. We point out that the root cause of both issues is that eq.(7) fails to account for the interdependence between $\omega$ and $\delta$ as in eq.(2). + +Proposed ATM Unlearning Update. The above root cause propels us to derive a new unlearning update that can holistically capture the nested data influence. To account for the interdependence between the adversarial perturbations and the model parameters in eq.(2), we take the complete expansion w.r.t. both $\omega$ and $\delta$ as in Lemma 1 below. + +Lemma 1. By expansion around both $\omega^{*}$ and $\delta (\omega^{*})$ , the approximate machine unlearning model parameter $\omega^u$ and the original model parameter $\omega^{*}$ has the following relation, + +$$ +\begin{array}{l} \frac {1}{n - 1} \sum_ {i = 1, i \neq i ^ {\dagger}} ^ {n} \nabla_ {\boldsymbol {\omega}} l (\boldsymbol {\omega} ^ {u}, \mathbf {x} _ {i} + \delta_ {i} (\boldsymbol {\omega} ^ {u})) \\ \approx \frac {1}{n - 1} \sum_ {i = 1, i \neq i ^ {\dagger}} ^ {n} \left[ \nabla_ {\omega} l \left(\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i} + \delta_ {i} \left(\boldsymbol {\omega} ^ {*}\right)\right) \right. \tag {9} \\ + \partial_ {\omega \omega} l \left(\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i} + \delta_ {i} \left(\boldsymbol {\omega} ^ {*}\right)\right) \left(\boldsymbol {\omega} ^ {u} - \boldsymbol {\omega} ^ {*}\right) \\ \left. + \partial_ {\boldsymbol {\omega} \delta} l (\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i} + \delta_ {i} (\boldsymbol {\omega} ^ {*})) (\delta_ {i} (\boldsymbol {\omega} ^ {u}) - \delta_ {i} (\boldsymbol {\omega} ^ {*})) \right]. \\ \end{array} +$$ + +Proof. Please refer to Appendix B.1. + +![](images/abb4a22bf9055ecd5bb11fdbd33969e720f11b20a9d7d7d195b6294f72c87c1c.jpg) + +The last line of eq.(9) is key to the sufficient removal of the data influence from ATM, which captures the interdependence between the adversarial perturbations and the model parameters. Based on Lemma 1, we can derive the ATM unlearning update in closed-form in Theorem 1 below. + +Theorem 1. Consider the adversarial training model with trained model parameter $\omega^{*}$ as in eq.(1). Let $(\mathbf{x}_{i^{\dagger}},y_{i^{\dagger}})$ be a datapoint in the training dataset to be forgotten. Let the machine learning update $\mathcal{U}(\boldsymbol {\omega}^*,i^{\dagger})$ take the following form + +$$ +\begin{array}{l} \mathcal {U} \left(\boldsymbol {\omega} ^ {*}, i ^ {\dagger}\right) := \left[ \sum_ {i = 1, i \neq i ^ {\dagger}} ^ {n} \underbrace {\mathrm {D} _ {\boldsymbol {\omega} \boldsymbol {\omega}} l \left(\boldsymbol {\omega} ^ {*} , \mathbf {x} _ {i} + \delta_ {i} \left(\boldsymbol {\omega} ^ {*}\right)\right)} _ {\text {T o t a l H e s s i a n}} \right] ^ {- 1} \tag {10} \\ \cdot \left[ \nabla_ {\boldsymbol {\omega}} l (\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i ^ {\dagger}} + \delta_ {i ^ {\dagger}} (\boldsymbol {\omega} ^ {*})) \right]. \\ \end{array} +$$ + +Then, the unlearning model with updated parameters $\omega^u \coloneqq \omega^* + \mathcal{U}(\omega^*, i^\dagger)$ satisfies the approximate unlearning criteria for the adversarial training model in eq.(6). + +Proof. Please refer to Appendix B.1. + +It turns out that the ATM unlearning in eq.(10) requires both direct Hessian and indirect Hessian (i.e., total Hessian + +in eq.(4)) to sufficiently capture the data influence, while previous methods for the STM unlearning have only the direct Hessian-related part (e.g., eq.(8)). The total Hessian term also appears in the second-order bi-level optimization literature, e.g., the Complete Newton method in [64]. + +A New Influence Function. Finally, we would like to remark that eq.(10) can be used to define a new influence function as follows to measure the nested data influence of a data point for ATM. It could serve as an independent interest, for example, to measure the marginal contribution of a data point to the model for valuation in data market [46] and influence-based defense against data poisoning attacks [18]. + +Definition 2. (Leave-one-out Adversarial Influence Function) For the adversarial training model given in eq.(1), the leave-one-out adversarial influence function for any $(\mathbf{x},y)$ in the training dataset is defined as + +$$ +\mathcal {I} (\mathbf {x}, y) = - \left[ \frac {1}{n} \sum_ {i = 1} ^ {n} \mathrm {D} _ {\omega \omega} l \left(\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i} + \boldsymbol {\delta} _ {i} ^ {*}\right) \right] ^ {- 1} \nabla_ {\omega} l \left(\boldsymbol {\omega} ^ {*}, \mathbf {x} + \boldsymbol {\delta} ^ {*}\right). +$$ + +Definition 2 utilizes total Hessian instead of direct Hessian-only as in [32], which captures the interdependence between adversarial perturbations and model parameters. This is different from recent work [14] which defines the adversarial influence function as a training sample's influence difference between two models: an STM and an ATM, while Definition 2 measures a training sample's influence difference when it is in or out for a single ATM. + +# 4. Proposed Method: MUt er + +Equipped with the ATM unlearning update, we propose MUt er, a three-stage unlearning method for ATM, which has two design considerations: 1) Support the more practical successive unlearning setting where multiple data points can be forgotten in sequence by keeping a selective variable set in memory (Sec.4.1); 2) Reduce the per-unlearning computational cost by introducing more efficient approximations and conversions to avoid direct computations of the most computational demanding Hessian inversions (Sec.4.2). The overall framework of MUt er is illustrated in Figure 2. We also present the complete algorithm in Appendix B.4. + +# 4.1. Three Stages of MUt er + +Successive Unlearning Setting. Denote the indices of datapoints that have already been forgotten at timestamp $r$ by $\{i_1^\dagger, \ldots, i_r^\dagger\}$ , the index of datapoint to be forgotten at timestamp $r + 1$ by $i_{r + 1}^\dagger = i^\dagger$ . Corollary 1 below extends Theorem 1 to support successive unlearning for ATM. + +Corollary 1. Considering the successive unlearning setting, let the machine unlearning update at the $r + 1$ -th timestamp + +$\mathfrak{U}_r(\omega^*, i_{r+1}^\dagger)$ take the following form + +$$ +\mathcal {U} _ {r} \left(\boldsymbol {\omega} ^ {*}, i _ {r + 1} ^ {\dagger}\right) := \left\{\overbrace {\left[ \sum_ {i = 1} ^ {n} \mathrm {D} _ {\boldsymbol {\omega} \boldsymbol {\omega}} l \left(\boldsymbol {\omega} ^ {*} , \mathbf {x} _ {i} + \boldsymbol {\delta} _ {i} ^ {*}\right) \right]} ^ {\mathcal {M} _ {0} [ \mathrm {D} _ {\boldsymbol {\omega} \boldsymbol {\omega}} ]} - \right. +$$ + +$$ +\overbrace {\left[ \sum_ {i = i _ {1} ^ {\dagger}} ^ {i _ {r} ^ {\dagger}} \mathrm {D} _ {\omega \omega} l \left(\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i} + \boldsymbol {\delta} _ {i} ^ {*}\right) \right] - \left[ \mathrm {D} _ {\omega \omega} l \left(\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i \dagger} + \boldsymbol {\delta} _ {i \dagger} ^ {*}\right) \right]} ^ {\text {P a r t o f} \mathcal {M} _ {r} [ \mathrm {D} _ {\omega \omega} ]} ^ {- 1} \tag {11} +$$ + +$$ +\cdot \overbrace {\left[ \sum_ {i = i _ {1} ^ {\dagger}} ^ {i _ {r} ^ {\dagger}} \nabla_ {\omega} l (\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i} + \boldsymbol {\delta} _ {i} ^ {*}) + \nabla_ {\omega} l (\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i ^ {\dagger}} + \boldsymbol {\delta} _ {i ^ {\dagger}} ^ {*}) \right]} ^ {\mathcal {M} _ {r} [ \nabla_ {\boldsymbol {\omega}} ]}. +$$ + +Then, the unlearning model with updated parameters $\omega_{r + 1}^{u}\coloneqq \omega^{*} + \mathbf{U}_{r}(\boldsymbol{\omega}^{*},i_{r + 1}^{\dagger})$ satisfies the approximate unlearning criteria for the adversarial training model in eq.(6). + +Proof. Please refer to Appendix B.2. + +Stage I. Pre-Unlearning. According to Corollary 1, it is a natural idea to pre-compute and keep in memory the total Hessian $\left[\sum_{i=1}^{n} \mathsf{D}_{\omega \omega} l(\boldsymbol{\omega}^*, \mathbf{x}_i + \boldsymbol{\delta}_i^*)\right]$ once the ATM is trained and before responding to unlearning requests, since it does not depend on the new point to be removed. Thus, we initialize a memory set $\mathcal{M}_0$ at $r = 0$ , which has three memory parts: $\mathcal{M}_0[\mathsf{D}_{\omega \omega}]$ for $\left[\sum_{i=1}^{n} \mathsf{D}_{\omega \omega} l(\boldsymbol{\omega}^*, \mathbf{x}_i + \boldsymbol{\delta}_i^*)\right]$ , $\mathcal{M}_0[\boldsymbol{\omega}^*]$ for $\boldsymbol{\omega}^*$ , and $\mathcal{M}_0[\nabla_{\boldsymbol{\omega}}]$ for $\nabla_{\boldsymbol{\omega}} = \mathbf{0}$ at $r = 0$ . + +Stage II. Unlearning. Upon receiving a new unlearning request to forget the $i^{\dagger}$ -th datapoint at timestamp $r + 1$ , Corollary 1 indicates that it suffices to compute the total Hessian and gradient only on $i^{\dagger}$ rather than the entire training set, once the memory is set up and maintained. We evaluate the following three parts in sequence: 1) The gradient on $i^{\dagger} \colon \nabla_{\omega} l(\boldsymbol{\omega}^{*}, \mathbf{x}_{i^{\dagger}} + \boldsymbol{\delta}_{i^{\dagger}}^{*})$ ; 2) The total Hessian on $i^{\dagger} \colon \mathrm{D}_{\omega} \omega l(\boldsymbol{\omega}^{*}, \mathbf{x}_{i^{\dagger}} + \boldsymbol{\delta}_{i^{\dagger}}^{*})$ ; 3) The unlearning update $\mathcal{U}_r(\boldsymbol{\omega}^*, i_{r+1}^{\dagger})$ in eq.(11) and the updated parameters $\boldsymbol{\omega}_{r+1}^u$ . In addition, we can also inject Gaussian noise by $\boldsymbol{\omega}_{r+1}^u + \mathbf{n}$ with $\mathbf{n} \sim \mathcal{N}(0, \sigma^2 \mathbf{I})$ to further smooth the remaining data influence to the discrepancy between eq.(3) and eq.(6). + +Stage III. Post-Unlearning. To support subsequent unlearning requests, we update $\mathcal{M}_{r + 1}$ based on Corollary 1: + +$$ +\mathcal {M} _ {r + 1} \left[ \mathrm {D} _ {\omega \omega} \right] = \mathcal {M} _ {r} \left[ \mathrm {D} _ {\omega \omega} \right] - \mathrm {D} _ {\omega \omega} l \left(\boldsymbol {\omega} ^ {*}, \mathbf {x} _ {i ^ {\dagger}} + \boldsymbol {\delta} _ {i ^ {\dagger}} ^ {*}\right); \tag {12} +$$ + +$$ +\mathcal {M} _ {r + 1} [ \nabla_ {\omega} ] = \mathcal {M} _ {r} [ \nabla_ {\omega} ] + \nabla_ {\omega} l \left(\omega^ {*}, \mathbf {x} _ {i ^ {\dagger}} + \boldsymbol {\delta} _ {i ^ {\dagger}} ^ {*}\right), \tag {13} +$$ + +where the former is the online update for $\left[\sum_{i=1}^{n} \mathrm{D}_{\omega \omega} l\left(\omega^{*}, \mathbf{x}_{i} + \boldsymbol{\delta}_{i}^{*}\right)\right] - \left[\sum_{i=i_{1}^{\dagger}}^{i_{1}^{\dagger} + 1} \mathrm{D}_{\omega \omega} l\left(\omega^{*}, \mathbf{x}_{i} + \boldsymbol{\delta}_{i}^{*}\right)\right]$ + +and the latter is for $\left[\sum_{i = i_1}^{i_{r + 1}}\nabla_{\omega}l(\boldsymbol{\omega}^*,\mathbf{x}_i + \boldsymbol{\delta}_i^*)\right]$ . + +![](images/f7186078cbb0413cac9155c9148967f6acfcd1491e6ca859ea8c76c3eaa3dce0.jpg) +Figure 2: The proposed MUt er framework. Stage I: the pre-unlearning stage prepares the initial memory $\mathcal{M}_0[\mathbb{D}_{\omega \omega}],\mathcal{M}_0[\nabla_{\omega}],\mathcal{M}_0[\omega^* ]$ . Stage II: the unlearning stage computes the total Hessian and gradient on the data to be forgotten and computes the ATM unlearning update by solving a linear system. Stage II: the post-unlearning stage updates $\mathcal{M}_{r + 1}[\mathbb{D}_{\omega \omega}]$ and $\mathcal{M}_{r + 1}[\nabla_{\omega}]$ to be prepared for the next unlearning request. + +# 4.2. Unlearning without Direct Hessian Inversions + +We now present the approximations and conversions to circumvent the most computationally expensive and potentially numerical unstable parts in the three stages, which are three Hessian matrix inversions: (Inv-1) The total Hessian inversion of $\left[\mathcal{M}_r[\mathrm{D}_{\omega \omega}] - \mathrm{D}_{\omega \omega}l(\boldsymbol{\omega}^*,\mathbf{x}_{i^\dagger} + \boldsymbol{\delta}_{i^\dagger}^*)\right]^{-1}$ ; (Inv-2) The partial Hessian inversion of $\partial_{\delta \delta}^{-1}l(\boldsymbol{\omega}^*,\mathbf{x}_{i^\dagger} + \boldsymbol{\delta}_{i^\dagger}^*)$ inside the total Hessian in Stage II; (Inv-3) The same $\partial_{\delta \delta}^{-1}l(\boldsymbol{\omega}^*,\mathbf{x}_{i^\dagger} + \boldsymbol{\delta}_{i^\dagger}^*)$ but in Stage I & III. + +Avoid Matrix Inversions (Inv-1/2) jointly by Schur Complement Conversion. After expanding the total Hessian as in eq.(4), we can reorganize $\left[\mathcal{M}_r[\mathbb{D}_{\omega \omega}] - \mathbb{D}_{\omega \omega}l(\boldsymbol{\omega}^*,\mathbf{x}_{i^\dagger} + \delta_{i^\dagger}^*)\right]$ into the following form $\mathbf{S} = \left[\mathcal{M}_r[\mathbb{D}_{\omega \omega}] - \partial_{\omega \omega}l_{i^\dagger}^*\right] - \left[-\partial_{\omega \delta}\partial_{\delta \delta}^{-1}\partial_{\delta \omega}l_{i^\dagger}^*\right]$ , which can be regarded as the Schur complement of the block matrix $\mathbf{H}$ : + +$$ +\mathbf {H} = \left[ \begin{array}{l l} \mathbf {H} _ {1 1} & \mathbf {H} _ {1 2} \\ \mathbf {H} _ {2 1} & \mathbf {H} _ {2 2} \end{array} \right] = \left[ \begin{array}{c c} \mathcal {M} _ {r} [ \mathrm {D} _ {\omega \omega} ] - \partial_ {\omega \omega} l _ {i ^ {\dagger}} ^ {*} & \partial_ {\omega \delta} l _ {i ^ {\dagger}} ^ {*} \\ \partial_ {\delta \omega} l _ {i ^ {\dagger}} ^ {*} & - \partial_ {\delta \delta} l _ {i ^ {\dagger}} ^ {*} \end{array} \right]. \tag {14} +$$ + +By Schur complement lemma, we can find the inversion of $\mathbf{S}$ to the inversion of $\mathbf{H}$ , then the unlearning update is equivalent to solving a linear system, as summarized in the following Theorem. + +Theorem 2. The unlearning update $\mathfrak{U}_r(\omega^*, i_{r+1}^\dagger)$ in eq.(11) can be equivalently computed by solving the linear system: + +$$ +\left[ \begin{array}{c c} \mathcal {M} _ {r} [ \mathrm {D} _ {\omega \omega} ] - \partial_ {\omega \omega} l _ {i ^ {\dagger}} ^ {*} & \partial_ {\omega \mathbf {x}} l _ {i ^ {\dagger}} ^ {*} \\ \partial_ {\mathbf {x} \omega} l _ {i ^ {\dagger}} ^ {*} & - \partial_ {\mathbf {x x}} l _ {i ^ {\dagger}} ^ {*} \end{array} \right] \left[ \begin{array}{c} \Delta \boldsymbol {\omega} \\ \Delta \boldsymbol {\alpha} \end{array} \right] = \left[ \begin{array}{c} \mathcal {M} _ {r} [ \nabla \omega ] + \nabla_ {\omega} l _ {i ^ {\dagger}} ^ {*} \\ \mathbf {0} \end{array} \right], +$$ + +where $\Delta \omega$ is the unlearning update $\mathcal{U}_r(\omega^*, i_{r+1}^\dagger)$ and $\Delta \alpha$ is an auxiliary variable that can be discarded. + +The linear system in Theorem 2 can be solved by conjugate gradient or fixed point methods, which are more efficient than computing the Hessian inversions (Inv-1/2) directly. + +Avoid Matrix Inversions (Inv-3) by Neumann Series Approximation. We expand $\partial_{\delta \delta}^{-1}l_i^*$ by Neumann Series: $\partial_{\delta \delta}^{-1}l_i^* = \lim_{k\to \infty}\sum_{j = 0}^{k}\left[\mathbf{I} - \partial_{\mathbf{xx}}l_i^*\right]^j$ . Then, clipping at order $k$ , we have the following approximation, + +$$ +\partial_ {\delta \delta} ^ {- 1} l _ {i} ^ {*} \approx \mathbf {I} + \left[ \mathbf {I} - \partial_ {\delta \delta} l _ {i} ^ {*} \right] + \dots + \left[ \mathbf {I} - \partial_ {\delta \delta} l _ {i} ^ {*} \right] ^ {k}. \tag {15} +$$ + +Each term in memory $\mathcal{M}_r[\mathrm{D}_{\omega \omega}]$ used in Stage I & III can be approximated by $\mathrm{D}_{\omega \omega}l_i^* \approx \overline{\mathrm{D}}_{\omega \omega}l_i^* :=$ + +$$ +\partial_ {\omega \omega} l _ {i} ^ {*} - \partial_ {\omega \delta} l _ {i} ^ {*} \left(\sum_ {j = 0} ^ {k} \left[ \mathbf {I} - \partial_ {\delta \delta} l _ {i} ^ {*} \right] ^ {j}\right) \partial_ {\delta \omega} l _ {i} ^ {*}. \tag {16} +$$ + +# 5. Experiments + +We conduct experimental evaluations on two groups of machine learning models and four common datasets, under two typical experiment settings in the unlearning literature [21-23, 26]. Our source code, experiment details, and more experiment results can be found in Supplement. + +# 5.1. Experiment Setup + +# 5.1.1 Models and Datasets + +Linear Models. We consider two linear models: 1) Ridge Regression (RR) with least square loss; 2) Logistic Regression (LR) with logistic loss, both are regularized by squared $\ell_2$ -norm with hyperparameter $\lambda = 1e - 4$ . + +Neural Network Models. We utilize the Wide ResNet model (i.e., Wide ResNet 28-10 model) [63] and consider the pretraining setting [22, 26] (also similar to the mixed-privacy removal setting [21]) for the neural network model as follows. We first pretrain a model on a core dataset with adversarial training. We then finetune the model on another target dataset with adversarial finetuning [28], where all layers are frozen except the last layer. We consider unlearning requests from only the target dataset used for the adversarial finetuning. + +Adversarial Training/Finetuning Algorithms. For outer-level, we utilize SGD to optimize the model parameters $\omega^{*}$ ; for inner-level, we utilize both PGD [39] and FGSM [24] to generate adversarial perturbations. The experiment results by PGD are reported in the paper, while the results by FGSM and more detailed training and finetuning settings are relegated to Appendix A.1 and A.3. + +Datasets. We consider four common datasets for the two settings above: (linear models) i) MNIST- $\mathbf{b}$ is the subset from MNIST with classes '1' and '7' for binary classification purpose; ii) Covtype is a dataset from the LIBSVM repository [10]; (neural network model with pretraining) iii) CIFAR-10 (target dataset) and the Downsampled ImageNet (core dataset) are both natural image datasets; iv) Lacuna-10 (target dataset) and Lacuna-100 (core dataset) are both face datasets. More detail can be found in Appendix A.2. + +# 5.1.2 Baseline Unlearning Methods + +We compare MUt er with six approximate unlearning methods (with their abbreviations in bold), all of which are originally designed for unlearning from standard training models. Since they utilize different Hessian terms in the unlearning update, for a fair comparison, we evaluate them under the same three-stage framework as MUt er but substitute in their corresponding unlearning update formulations. (1) Newton unlearning [26] and (2) Newton unlearning measured with adversarial perturbation (Newton-delta): both methods utilize the Newton step as the unlearning update, where the former computes at the original samples (i.e., $\left[\sum_{i = 1,i\neq i\dagger}^{n}\partial_{\omega \omega}l(\boldsymbol{\omega}^{*},\mathbf{x}_{i})\right]^{-1}\nabla_{\omega}l(\boldsymbol{\omega}^{*},\mathbf{x}_{i\dagger})$ and the latter at the adversarially perturbed samples (i.e., $\left[\sum_{i = 1,i\neq i\dagger}^{n}\partial_{\omega \omega}l(\boldsymbol{\omega}^{*},\mathbf{x}_{i} + \boldsymbol{\delta}_{i}^{*})\right]^{-1}\nabla_{\omega}l(\boldsymbol{\omega}^{*},\mathbf{x}_{i\dagger} + \boldsymbol{\delta}_{i\dagger}^{*})$ ). Similarly, we have (3) Fisher unlearning [22] and (4) Fisher-delta, which utilize the Fisher matrix $(\nabla_{\omega}l\cdot \nabla_{\omega}^{\top}l)$ to approximate the direct Hessian $\partial_{\omega \omega}l$ . (5) Influence function-based unlearning [32, 40] and (6) Influence-delta, which utilize the influence function for STM for the unlearning update. + +Meanwhile, we utilize (7) Retrain-from-scratch as the golden standard reference, which applies the same adversarial training/finetuning algorithms to retrain/re-finetune the model on the remaining data to obtain $\omega_{-i\dagger}^{*}$ in eq.(3). + +# 5.1.3 Evaluation Metrics + +We measure four aspects of the unlearning performance: 1) Effectiveness measures the closeness of the unlearned ATM compared to the golden standard Retrain, for which we utilize the $\ell_2$ -norm difference between the model parameter vectors, i.e., $\| \boldsymbol{\omega}^u - \boldsymbol{\omega}_{-i^\dagger}^*\|_2$ ; 2) Accuracy measures the clean accuracy of the unlearned ATM, for which we utilize the accuracy on clean test samples; 3) Robustness measures the adversarial accuracy of the unlearned ATM, for which we + +![](images/4afe7bbf0ba6b56c8523ef5d19617b8520776a4229d1c6cd31795b8e4ec439e9.jpg) + +![](images/35c6e74f40f345acdceba95852e24680e1b867577f3afac37d3a4878759a95b2.jpg) + +![](images/9bc1066fe0a1f511b909a0cb64ffccef84ff021afe13f0e67968316982485dfb.jpg) + +![](images/4382d88274c5ed09a758410e7ce0f5f61cb6ece613f9531cf56ca4f735fc644c.jpg) + +![](images/12d3b37e9d690e749d929c53e69791414955c90c0b539ae2d60891327bca19ec.jpg) + +![](images/80a7067843a62b970e9103df3197b39178d2750d33b0d1c3edfe511a450c19ca.jpg) +Figure 3: Evaluation results on Logistic Regression Model: Effectiveness (top), Accuracy (middle), and Robustness (bottom) on datasets MNIST-b (left column), Covtype (right column). Large plots have greater removal numbers: $1\%$ , $2\%$ , $\cdots$ , $5\%$ ; the inside small plots have fewer removal numbers: $1,2,\cdots,5$ . + +![](images/754bc211380f4d6c78d872df2248456c4ccb19ef2630c0da505970a3cd0b55b1.jpg) + +utilize the accuracy on adversarial perturbed test samples; 4) Efficiency measures the unlearning time the unlearning method takes to respond the unlearning request, for which we report CPU time. + +# 5.2. Experiment Results + +# 5.2.1 Results with Linear Model + +Figure 3 reports the experiment results with logistic regression model on the MNIST-b and Covtypes datasets. More results with ridge regression are deferred to Appendix A.3. + +Effectiveness. Top row of Figure 3 shows the effectiveness comparison. All compared methods have increased model parameter distance with the increasing number of unlearning + +![](images/a73fdcc799b61851c5bf67004c89ee7faba69f0430875a5920da4cfaf0419553.jpg) + +![](images/83ba5f1b25738a31a57e20f15cad1bb753270bfdbe402b6182adca821842378a.jpg) + +![](images/5e5d26435969fe46870b32b04bbe8957efb787ab6ad4d45938350c6dadca044e.jpg) + +![](images/a81c2e680793d79c43a011598a0e0b37139e7d3bf307a330a0770ea4eb30f4ec.jpg) + +![](images/3f87baacd32401b9f056d0598dcde1102b78044f81e0add1831d7aaa73887589.jpg) +Figure 4: Evaluation results on Neural Network: Effectiveness (top), Accuracy (middle), and Robustness (bottom) on datasets Lacuna-10 (left column) and CIFAR-10 (right column), under removal numbers $(1,0.4\%, 1\%, 2\%, 4\%, 8\%)$ . + +![](images/15861c24a1c405179ae16bb1a768abcbe8bbf5c9f3cdc673914115f8d39da6e3.jpg) + +
Model TypeRemoval NumberMNIST-bCovtype
FisherF-deltaMIterRetrainFisherF-deltaMIterRetrain
LR10.0020.0020.009630.0020.0020.007192
50.0100.0120.052630.0090.0110.037194
100.0190.0210.106620.0180.0220.071194
RR10.0020.0020.009640.0020.0020.006200
50.0090.0110.057650.0110.0120.032206
100.0180.0190.097650.0190.0200.064205
+ +requests, which is due to the decreased approximation capability of the approximate unlearning criteria. MUter achieves the smallest deviation from Retrain and outperforms all the compared methods, which is because its ATM unlearning update sufficiently captures the nested data influence in ATM. + +Accuracy. Middle row of Figure 3 shows the clean accuracy comparison. All unlearning methods do not show a signifi + +Table 1: Efficiency results with linear models of logistic regression (top) and ridge regression (bottom): The unlearning time (in seconds) of Fisher, Fisher-delta, MUt er and Retrain under varying removal numbers: 1, 5, 10. + +
Removal NumberLacuna-10CIFAR-10
FisherF-deltaMUtErRetrainFisherF-deltaMUtErRetrain
11.471.664.189351.511.733.815224
57.768.4121.379347.548.5818.645294
1015.5116.8241.6993215.3416.4237.575260
+ +Table 2: Efficiency results with Neural Network: The unlearning time (in seconds) of Fisher, Fisher-delta, MUt er and Retrain under varying removal numbers: 1, 5, 10. + +cant drop in clean accuracy after data forgotten. In general, $MUtEr$ is among the methods that achieve higher accuracy and exhibits close consistency with Retrain. + +Robustness. Bottom row of Figure 3 shows the robustness comparison. When the number of forgotten requests is small, most methods have little variation in perturbed accuracy. When the forgotten number becomes larger, all baseline unlearning methods have an obvious decrease in perturbed accuracy, while MUt er still shows high perturbed accuracy and has the closest proximity to Retrain. + +Efficiency. Table 1 shows the efficiency comparison. MUt er has significant efficiency improvement over Retrain, which is the utmost desideratum of the unlearning method. In addition, we compare with Fisher and Fisher-delta, which are the most efficient methods among the six baseline methods due to the more efficient Fisher information matrix approximation. MUt er takes more CPU time because it computes the total Hessian to obtain a more holistic data influence measure, while the baseline methods compute only the (approximate) direct Hessian and omit the indirect Hessian. Thus, the small increase in CPU time is the necessary tax to pay in exchange for more effective unlearning. + +Tradeoff between deletion effectiveness, accuracy, and robustness. According to the above results, there is a tradeoff between efficient and deletion effectiveness, accuracy, and robustness. That is, $MUtEr$ takes slightly longer than direct Hessian-only unlearning methods due to the additional computation of the indirect Hessian. However, this extra computation is worthwhile as $MUtEr$ offers improved deletion effectiveness, accuracy, and robustness. + +# 5.2.2 Results with Neural Network Model + +Figure 4 summarizes the results of effectiveness, accuracy, and robustness on the two datasets for the neural network model with pretraining. MUt er has the smallest difference of parameter distance with Retrain, which indicates that MUt er generates the most similar unlearning model to the Retrain model. In addition, MUt er has the most consistent behaviour with Retrain in terms of clean accuracy and perturbation accuracy. In terms of efficiency, Table 2 reports the comparison with Retrain and two most efficient baseline methods Fisher and Fisher-delta. Similar to the linear + +![](images/25a2f5f6f29b3319475d2a42d728ad31266fce976a66d471de7e54bb1a024fe5.jpg) +Figure 5: Effect of Gaussian noise injection: Effectiveness (left), Accuracy (middle), and Robustness (right) versus the standard variation $\sigma$ of Gaussian noise in log scale, under the case of removing $5\%$ samples and on the Lacuna-10 dataset. + +![](images/77d03821b289f247a743d56bf2ade4c7706f59c4674980356d35b3c5414a8ae3.jpg) + +![](images/ae00c2840e6e62d9da79df0ee15f1fb7eba876aecf2c9775abe499e6d22dd95c.jpg) + +model case, MUt er has significant efficiency improvement over Retrain. Although MUt er costs more unlearning time than the approximate methods, it provides significantly more effective, more accurate, and more robust unlearned ATM. + +Effect of Varying Magnitudes of Gaussian Noise. Figure 5 shows the effectiveness, accuracy, and robustness comparisons under varying standard variations of Gaussian noise $(\sigma)$ injected by $\omega_{r + 1}^u +\mathbf{n}$ with $\mathbf{n}\sim \mathcal{N}(0,\sigma^2\mathbf{I})$ . All methods get worse unlearning model performance with larger $\sigma$ , but MUt er maintains the best performance for all $\sigma$ ’s among all compared unlearning methods. + +# 6. Conclusion + +In this paper, we studied a new joint privacy-robustness problem of machine unlearning from adversarial training models to simultaneously meet the emerging privacy regulations on Right to be Forgotten and ensure the adversarial robustness of the model. We proposed a new unlearning method called Muter, which is underpinned by a total Hessian-based measure to sufficiently capture the data influence on both model parameters and adversarial perturbations. We further introduced the Schur complement conversion and the Neumann series approximation to mitigate the computational cost. Our methods show significant enhancement in effectiveness and efficiency compared to baseline methods. + +As future works, several directions can be further explored: 1) extending $MUter$ to other adversarial training variants like adversarial regularization; 2) further reducing the memory cost by considering low-rank/k-fact approximations to approximate the Hessian matrix, e.g., [25]; 3) studying the approximation capability of the new influence function inspired by $MUter$ , e.g., across different depths of neural networks [4]; 4) exploring the potential connection between the new influence function with proximal Bregman response function [2]. + +# 7. Acknowledgement + +The authors would like to thank the anonymous reviewers for their constructive comments. This research has been + +funded in part by National Science Foundation of China (NSFC) 62206207, 62102300, 62072395, and U20A20178, National Key Research and Development Program of China 2020AAA0107705, National Science Foundation (NSF) CNS-2124104, CNS-2125530, and National Institute of Health (NIH) R01ES033241. + +# References + +[1] Martin Abadi, Andy Chu, Ian Goodfellow, H Brendan McMahan, Ilya Mironov, Kunal Talwar, and Li Zhang. Deep learning with differential privacy. In Proceedings of the 2016 ACM SIGSAC conference on computer and communications security, 2016. 1 +[2] Juhan Bae, Nathan Ng, Alston Lo, Marzyeh Ghassemi, and Roger B. Grosse. If influence functions are the answer, then what is the question? In NeurIPS, 2022. 9 +[3] Tao Bai, Jinqi Luo, Jun Zhao, Bihan Wen, and Qian Wang. Recent advances in adversarial training for adversarial robustness. In Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence, pages 4312-4321, 8 2021. Survey Track. 1 +[4] Samyadeep Basu, Phillip Pope, and Soheil Feizi. Influence functions in deep learning are fragile. In 9th International Conference on Learning Representations, ICLR 2021, Virtual Event, Austria, May 3-7, 2021, 2021. 9 +[5] Lucas Bourtoule, Varun Chandrasekaran, Christopher A. Choquette-Choo, Hengrui Jia, Adelin Travers, Baiwu Zhang, David Lie, and Nicolas Papernot. Machine unlearning. In 42nd IEEE Symposium on Security and Privacy, 2021. 1, 3 +[6] Jonathan Brophy and Daniel Lowd. Machine unlearning for random forests. In International Conference on Machine Learning, pages 1092-1104, 2021. 3 +[7] Qiong Cao, Li Shen, Weidi Xie, Omkar M. Parkhi, and Andrew Zisserman. Vggface2: A dataset for recognising faces across pose and age. In 2018 13th IEEE International Conference on Automatic Face Gesture Recognition (FG 2018), pages 67-74, 2018. 12 +[8] Yinzhi Cao and Junfeng Yang. Towards making systems forget with machine unlearning. In 2015 IEEE Symposium on Security and Privacy, pages 463-480. IEEE, 2015. 1, 3 + +[9] Nicholas Carlini and David Wagner. Towards evaluating the robustness of neural networks. In 2017 IEEE Symposium on Security and Privacy. IEEE Computer Society, 2017. 1 +[10] Chih-Chung Chang and Chih-Jen Lin. Libsvm: A library for support vector machines. ACM Trans. Intell. Syst. Technol., 2(3), may 2011. 7 +[11] Chong Chen, Fei Sun, Min Zhang, and Bolin Ding. Recommendation unlearning. In Proceedings of the ACM Web Conference 2022, pages 2768-2777, 2022. 3 +[12] Min Chen, Zhikun Zhang, Tianhao Wang, Michael Backes, Mathias Humbert, and Yang Zhang. Graph unlearning. In Proceedings of the ACM Conference on Computer and Communications Security 2022, 2022. 3 +[13] John M Danskin. The theory of max-min and its application to weapons allocation problems, volume 5. Springer Science & Business Media, 2012. 4 +[14] Zhun Deng, Cynthia Dwork, Jialiang Wang, and Linjun Zhang. Interpreting robust optimization via adversarial influence functions. In Proceedings of the 37th International Conference on Machine Learning, volume 119, 2020. 5 +[15] Federal Trade Commission. California company settles ftc allegations it deceived consumers about use of facial recognition in photo storage app, January 2021. 1 +[16] Matt Fredrikson, Somesh Jha, and Thomas Ristenpart. Model inversion attacks that exploit confidence information and basic countermeasures. In Proceedings of the 22nd ACM SIGSAC conference on computer and communications security, pages 1322-1333, 2015. 1 +[17] Regulation (EU) 2016/679 of the European parliament and of the council of 27 April 2016, 2016. 1 +[18] Amirata Ghorbani and James Zou. Data shapley: Equitable valuation of data for machine learning. In International Conference on Machine Learning, pages 2242-2251, 2019. 5 +[19] Antonio A Ginart, Melody Y Guan, Gregory Valiant, and James Zou. Making ai forget you: data deletion in machine learning. In Proceedings of the 33rd International Conference on Neural Information Processing Systems, 2019. 3 +[20] Jairo Giraldo, Alvaro Cardenas, Murat Kantarcioglu, and Jonathan Katz. Adversarial classification under differential privacy. In Network and Distributed Systems Security (NDSS) Symposium 2020, 2020. 1 +[21] Aditya Golatkar, Alessandro Achille, Avinash Ravichandran, Marzia Polito, and Stefano Soatto. Mixed-privacy forgetting in deep networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 792–801, 2021. 1, 4, 6 +[22] Aditya Golatkar, Alessandro Achille, and Stefano Soatto. Eternal sunshine of the spotless net: Selective forgetting in deep networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9304-9312, 2020. 1, 3, 6, 7, 12 +[23] Aditya Golatkar, Alessandro Achille, and Stefano Soatto. Forgetting outside the box: Scrubbing deep networks of information accessible from input-output observations. In European Conference on Computer Vision, 2020. 1, 3, 6 +[24] Ian J. Goodfellow, Jonathon Shlens, and Christian Szegedy. Explaining and harnessing adversarial examples. In Yoshua + +Bengio and Yann LeCun, editors, 3rd International Conference on Learning Representations, 2015. 1, 7 +[25] Roger Grosse, Juhan Bae, Cem Anil, Nelson Elhage, Alex Tamkin, Amirhossein Tajdini, Benoit Steiner, Dustin Li, Esin Durmus, Ethan Perez, et al. Studying large language model generalization with influence functions. arXiv preprint arXiv:2308.03296, 2023. 9 +[26] Chuan Guo, Tom Goldstein, Awni Y. Hannun, and Laurens van der Maaten. Certified data removal from machine learning models. In Proceedings of the 37th International Conference on Machine Learning, 2020. 1, 3, 4, 6, 7 +[27] Jamie Hayes, Borja Balle, and M Pawan Kumar. Learning to be adversarially robust and differentially private. arXiv preprint arXiv:2201.02265, 2022. 1 +[28] Dan Hendrycks, Kimin Lee, and Mantas Mazeika. Using pre-training can improve model robustness and uncertainty. In Kamalika Chaudhuri and Ruslan Salakhutdinov, editors, Proceedings of the 36th International Conference on Machine Learning, volume 97 of Proceedings of Machine Learning Research, pages 2712-2721, 09-15 Jun 2019. 6 +[29] Dan Hendrycks, Kimin Lee, and Mantas Mazeika. Using pre-training can improve model robustness and uncertainty. In International Conference on Machine Learning, pages 2712-2721, 2019. 12 +[30] Ruitong Huang, Bing Xu, Dale Schuurmans, and Csaba Szepesvári. Learning with a strong adversary. CoRR, abs/1511.03034, 2015. 1, 3 +[31] Zachary Izzo, Mary Anne Smart, Kamalika Chaudhuri, and James Zou. Approximate data deletion from machine learning models. In International Conference on Artificial Intelligence and Statistics, pages 2008-2016, 2021. 1, 3 +[32] Pang Wei Koh and Percy Liang. Understanding black-box predictions via influence functions. In International Conference on Machine Learning, 2017. 5, 7, 12 +[33] Haowen Lin, Jian Lou, Li Xiong, and Cyrus Shahabi. Integer-arithmetic-only certified robustness for quantized neural networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7828-7837, 2021. 1 +[34] Shen Lin, Xiaoyu Zhang, Chenyang Chen, Xiaofeng Chen, and Willy Susilo. Erm-ktp: Knowledge-level machine unlearning via knowledge transfer. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2023. 3 +[35] Junxu Liu, Jian Lou, Li Xiong, Jinfei Liu, and Xiaofeng Meng. Projected federated averaging with heterogeneous differential privacy. Proceedings of the VLDB Endowment, 15(4):828-840, 2021. 1 +[36] Yang Liu, Mingyuan Fan, Cen Chen, Ximeng Liu, Zhuo Ma, Li Wang, and Jianfeng Ma. Backdoor defense with machine unlearning. In IEEE INFOCOM 2022 - IEEE Conference on Computer Communications, page 280-289, 2022. 1 +[37] Jian Lou and Yiu-ming Cheung. An uplink communication-efficient approach to featurewise distributed sparse optimization with differential privacy. IEEE Transactions on Neural Networks and Learning Systems, 32(10):4529-4543, 2020. 1 +[38] Jie Ma, Xiangyuan Lan, Bineng Zhong, Guorong Li, Zhenjun Tang, Xianxian Li, and Rongrong Ji. Robust tracking via + +uncertainty-aware semantic consistency. IEEE Transactions on Circuits and Systems for Video Technology, 33(4):1740-1751, 2022. 1 +[39] Aleksander Madry, Aleksandar Makelov, Ludwig Schmidt, Dimitris Tsipras, and Adrian Vladu. Towards deep learning models resistant to adversarial attacks. In 6th International Conference on Learning Representations, 2018. 1, 7 +[40] Ananth Mahadevan and Michael Mathioudakis. Certifiable machine unlearning for linear models. arXiv preprint arXiv:2106.15093, 2021. 3, 7 +[41] Neil G Marchant, Benjamin IP Rubinstein, and Scott Alfeld. Hard to forget: Poisoning attacks on certified machine unlearning. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 7691-7700, 2022. 1 +[42] Brendan McMahan, Eider Moore, Daniel Ramage, Seth Hampson, and Blaise Aguera y Arcas. Communication-efficient learning of deep networks from decentralized data. In Artificial intelligence and statistics, 2017. 1 +[43] Ronak Mehta, Sourav Pal, Vikas Singh, and Sathya N. Ravi. Deep unlearning via randomized conditionally independent hessian. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 10422-10431, June 2022. 1, 3 +[44] Seth Neel, Aaron Roth, and Saeed Sharifi-Malvajerdi. Descent-to-delete: Gradient-based methods for machine unlearning. In Algorithmic Learning Theory, 2021. 1 +[45] Nicolas Papernot, Patrick McDaniel, Arunesh Sinha, and Michael P Wellman. Sok: Security and privacy in machine learning. In 2018 IEEE European Symposium on Security and Privacy (EuroS&P), pages 399-414. IEEE, 2018. 1 +[46] Jian Pei. A survey on data pricing: from economics to data science. IEEE Transactions on knowledge and Data Engineering, 2020. 5 +[47] Hai Phan, My T Thai, Han Hu, Ruoming Jin, Tong Sun, and Dejing Dou. Scalable differential privacy with certified robustness in adversarial learning. In International Conference on Machine Learning, pages 7683-7694, 2020. 1 +[48] NhatHai Phan, Minh N. Vu, Yang Liu, Ruoming Jin, Dejing Dou, Xintao Wu, and My T. Thai. Heterogeneous gaussian mechanism: Preserving differential privacy in deep learning with provable robustness. In Sarit Kraus, editor, Proceedings of the Twenty-Eighth International Joint Conference on Artificial Intelligence, pages 4753-4759, 2019. 1 +[49] Ayush Sekhari, Jayadev Acharya, Gautam Kamath, and Ananda Theertha Suresh. Remember what you want to forget: Algorithms for machine unlearning. Advances in Neural Information Processing Systems, 34:18075-18086, 2021. 3, 4 +[50] Uri Shaham, Yutaro Yamada, and Sahand Negahban. Understanding adversarial training: Increasing local stability of supervised models through robust optimization. Neurocomputing, 307:195-204, 2018. 3 +[51] Reza Shokri, Marco Stronati, Congzheng Song, and Vitaly Shmatikov. Membership inference attacks against machine learning models. In 2017 IEEE Symposium on Security and Privacy, pages 3-18. IEEE, 2017. 1 +[52] Liwei Song, Reza Shokri, and Prateek Mittal. Privacy risks of securing machine learning models against adversarial exam + +plies. In Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security, 2019. 1 +[53] Qiheng Sun, Xiang Li, Jiayao Zhang, Li Xiong, Weiran Liu, Jinfei Liu, Zhan Qin, and Kui Ren. Shapleyfl: Robust federated learning based on shapley value. In Proceedings of the 29th ACM SIGKDD Conference on Knowledge Discovery and Data Mining, pages 2096-2108, 2023. 1 +[54] Christian Szegedy, Wojciech Zaremba, Ilya Sutskever, Joan Bruna, Dumitru Erhan, Ian J. Goodfellow, and Rob Fergus. Intriguing properties of neural networks. In Yoshua Bengio and Yann LeCun, editors, 2nd International Conference on Learning Representations, 2014. 1 +[55] Farnaz Tahmasebian, Jian Lou, and Li Xiong. Robustfed: a truth inference approach for robust federated learning. In Proceedings of the 31st ACM International Conference on Information & Knowledge Management, 2022. 1 +[56] Pengfei Tang, Wenjie Wang, Jian Lou, and Li Xiong. Generating adversarial examples with distance constrained adversarial imitation networks. IEEE Transactions on Dependable and Secure Computing, 19(6):4145-4155, 2021. +[57] Anvith Thudi, Gabriel Deza, Varun Chandrasekaran, and Nicolas Papernot. Unrolling sgd: Understanding factors influencing machine unlearning. In 2022 IEEE 7th European Symposium on Security and Privacy (EuroS&P), pages 303-319. IEEE, 2022. 4 +[58] Anvith Thudi, Hengrui Jia, Ilia Shumailov, and Nicolas Papernot. On the necessity of auditable algorithmic definitions for machine unlearning. In 31st USENIX Security Symposium (USENIX Security 22), pages 4007-4022, 2022. 1 +[59] Boxi Wu, Jindong Gu, Zhifeng Li, Deng Cai, Xiaofei He, and Wei Liu. Towards efficient adversarial training on vision transformers. In European Conference on Computer Vision, pages 307-325, 2022. 1 +[60] Yinjun Wu, Edgar Dobriban, and Susan Davidson. Deltagrad: Rapid retraining of machine learning models. In International Conference on Machine Learning, 2020. 1, 4 +[61] Jingwen Ye, Yifang Fu, Jie Song, Xingyi Yang, Songhua Liu, Xin Jin, Mingli Song, and Xinchao Wang. Learning with recoverable forgetting. In European Conference on Computer Vision, pages 87-103, 2022. 1 +[62] Xiaoyong Yuan, Pan He, Qile Zhu, and Xiaolin Li. Adversarial examples: Attacks and defenses for deep learning. IEEE transactions on neural networks and learning systems, 30(9):2805-2824, 2019. 1 +[63] Sergey Zagoruyko and Nikos Komodakis. Wide residual networks. In British Machine Vision Conference, 2016. 6 +[64] Guojun Zhang, Kaiwen Wu, Pascal Poupart, and Yaoliang Yu. Newton-type methods for minimax optimization. arXiv preprint arXiv:2006.14592, 2020. 5 +[65] Peng-Fei Zhang, Guangdong Bai, Zi Huang, and Xin-Shun Xu. Machine unlearning for image retrieval: A generative scrubbing approach. In Proceedings of the 30th ACM International Conference on Multimedia, 2022. 1 +[66] Xiaoyu Zhang, Yulin Jin, Tao Wang, Jian Lou, and Xiaofeng Chen. Purifier: Plug-and-play backdoor mitigation for pretrained models via anomaly activation suppression. In Proceedings of the 30th ACM International Conference on Multimedia, pages 4291-4299, 2022. 1 \ No newline at end of file diff --git a/2023/MUter_ Machine Unlearning on Adversarially Trained Models/images.zip b/2023/MUter_ Machine Unlearning on Adversarially Trained Models/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..55645ba7d6b0da1de470ad4c0f2a267b20ec7bfd --- /dev/null +++ b/2023/MUter_ Machine Unlearning on Adversarially Trained Models/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:7e859043164efa82ea3ef316a2a8ce957273a17bce8b3865527f7cb8ef81d5d3 +size 570566 diff --git a/2023/MUter_ Machine Unlearning on Adversarially Trained Models/layout.json b/2023/MUter_ Machine Unlearning on Adversarially Trained Models/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..e57d6505e85e139d825446f8e4d4443e49ac795a --- /dev/null +++ b/2023/MUter_ Machine Unlearning on Adversarially Trained Models/layout.json @@ -0,0 +1,11463 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 112, + 153, + 465, + 170 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 112, + 153, + 465, + 170 + ], + "spans": [ + { + "bbox": [ + 112, + 153, + 465, + 170 + ], + "type": "text", + "content": "MUt er: Machine Unlearning on Adversarily Trained Models" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "spans": [ + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "text", + "content": "Junxu Liu" + }, + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "inline_equation", + "content": "^{1,*}" + }, + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "text", + "content": ", Mingsheng Xue" + }, + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "inline_equation", + "content": "^{2,*}" + }, + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "text", + "content": ", Jian Lou" + }, + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "inline_equation", + "content": "^{3,6,\\dagger}" + }, + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "text", + "content": ", Xiaoyu Zhang" + }, + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "text", + "content": ", Li Xiong" + }, + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "inline_equation", + "content": "^{5}" + }, + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "text", + "content": ", Zhan Qin" + }, + { + "bbox": [ + 110, + 190, + 465, + 203 + ], + "type": "inline_equation", + "content": "^{3,6}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 84, + 203, + 493, + 229 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 84, + 203, + 493, + 229 + ], + "spans": [ + { + "bbox": [ + 84, + 203, + 493, + 229 + ], + "type": "text", + "content": "1Renmin University of China 2Guangzhou Institute of Technology, Xidian University 3Zhejiang University 4Xidian University 5Emory University 6ZJU-Hangzhou Global Scientific and Technological Innovation Center" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 108, + 230, + 470, + 241 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 108, + 230, + 470, + 241 + ], + "spans": [ + { + "bbox": [ + 108, + 230, + 470, + 241 + ], + "type": "text", + "content": "junxu_liu@ruc.edu.cn xuemingsheng@stu.xidian.edu.cn jian.lou@zju.edu.cn" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 132, + 244, + 445, + 254 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 132, + 244, + 445, + 254 + ], + "spans": [ + { + "bbox": [ + 132, + 244, + 445, + 254 + ], + "type": "text", + "content": "xiaoyuzhang@xidian.edu.cn lxiong@emory.edu qinzhan@zju.edu.cn" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 149, + 279, + 192, + 290 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 149, + 279, + 192, + 290 + ], + "spans": [ + { + "bbox": [ + 149, + 279, + 192, + 290 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 60, + 303, + 282, + 597 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 303, + 282, + 597 + ], + "spans": [ + { + "bbox": [ + 60, + 303, + 282, + 597 + ], + "type": "text", + "content": "Machine unlearning is an emerging task of removing the influence of selected training datapoints from a trained model upon data deletion requests, which echoes the widely enforced data regulations mandating the Right to be Forgotten. Many unlearning methods have been proposed recently, achieving significant efficiency gains over the naive baseline of retraining from scratch. However, existing methods focus exclusively on unlearning from standard training models and do not apply to adversarial training models (ATMs) despite their popularity as effective defenses against adversarial examples. During adversarial training, the training data are involved in not only an outer loop for minimizing the training loss, but also an inner loop for generating the adversarial perturbation. Such bi-level optimization greatly complicates the influence measure for the data to be deleted and renders the unlearning more challenging than standard model training with single-level optimization. This paper proposes a new approach called MUt er for unlearning from ATMs. We derive a closed-form unlearning step underpinned by a total Hessian-related data influence measure, while existing methods can mis-capture the data influence associated with the indirect Hessian part. We further alleviate the computational cost by introducing a series of approximations and conversions to avoid the most computationally demanding parts of Hessian inversions. The efficiency and effectiveness of MUt er have been validated through experiments on four datasets using both linear and neural network models." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 61, + 620, + 135, + 632 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 620, + 135, + 632 + ], + "spans": [ + { + "bbox": [ + 61, + 620, + 135, + 632 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 60, + 639, + 280, + 683 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 639, + 280, + 683 + ], + "spans": [ + { + "bbox": [ + 60, + 639, + 280, + 683 + ], + "type": "text", + "content": "Machine learning (ML) models are increasingly applied to a broad range of applications, accompanied by growing concerns about their privacy and robustness issues. Both issues are actively studied in recent years [45]. On the" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 297, + 280, + 518, + 444 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 280, + 518, + 444 + ], + "spans": [ + { + "bbox": [ + 297, + 280, + 518, + 444 + ], + "type": "text", + "content": "privacy side, model inversion attack [16] and membership inference attack [51] reveal that the trained ML model contains sensitive information of its training data, which can cause privacy loss for individuals contributing their data for model training. On the robustness side, adversarial example attack is one of the most well-recognized robustness attacks [24, 30, 39, 62]. It can easily fool an undefended model, e.g., standard training model (STM), to misclassify by a small adversarial perturbation on the input [9, 24, 39]. Many works focus either on the privacy [1, 35, 37, 42, 51] or on the robustness aspect [9, 33, 38, 53–56, 66], few works studied both. Yet, it is critical to consider privacy and robustness jointly [20, 27, 36, 41, 47, 48, 52] to build ML models to simultaneously meet data privacy regulations and ensure robustness against adversarial threats." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 296, + 446, + 517, + 511 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 446, + 517, + 511 + ], + "spans": [ + { + "bbox": [ + 296, + 446, + 517, + 511 + ], + "type": "text", + "content": "In this paper, we target a new joint privacy-robustness problem to simultaneously meet emerging privacy regulations and ensure adversarial robustness of the model, which has not been examined before: how to efficiently and effectively remove the influence of a training datapoint from an adversarially trained model upon data deletion request?" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 512, + 518, + 666 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 512, + 518, + 666 + ], + "spans": [ + { + "bbox": [ + 296, + 512, + 518, + 666 + ], + "type": "text", + "content": "The privacy need is driven by the widely enacted user data regulations that enforce the Right to be Forgotten, for example, the European Union's GDPR [17], the California Consumer Privacy Act (CCPA), and Canada's proposed Consumer Privacy Protection Act (CPPA). These regulations mandate the deletion of personal data upon user requests and can even include the deletion of models and algorithms derived from the user data, e.g., the Federal Trade Commission [15]. Machine unlearning [5,8] aims to obtain an updated model with the influence of the target datapoint removed in an effective and efficient way. That is, the updated model should be similar to the model obtained by the computationally expensive retraining-from-scratch approach, while consuming less computation [21-23,26,31,43,44,58,60,61,65]." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 296, + 667, + 518, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 667, + 518, + 711 + ], + "spans": [ + { + "bbox": [ + 296, + 667, + 518, + 711 + ], + "type": "text", + "content": "The robustness is achieved by the adversarial training model (ATM) [3, 24, 30, 39, 59], which is a popular and effective defense for enhancing the model robustness against adversarial examples by creating and incorporating adver" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 57, + 7, + 102, + 39 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 7, + 102, + 39 + ], + "spans": [ + { + "bbox": [ + 57, + 7, + 102, + 39 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 138, + 5, + 485, + 41 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 138, + 5, + 485, + 41 + ], + "spans": [ + { + "bbox": [ + 138, + 5, + 485, + 41 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 71, + 692, + 133, + 701 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 692, + 133, + 701 + ], + "spans": [ + { + "bbox": [ + 71, + 692, + 133, + 701 + ], + "type": "text", + "content": "*Equal contribution." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 73, + 701, + 143, + 710 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 73, + 701, + 143, + 710 + ], + "spans": [ + { + "bbox": [ + 73, + 701, + 143, + 710 + ], + "type": "text", + "content": "† Corresponding Author." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 279, + 737, + 298, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 737, + 298, + 746 + ], + "spans": [ + { + "bbox": [ + 279, + 737, + 298, + 746 + ], + "type": "text", + "content": "4892" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 85, + 124, + 495, + 264 + ], + "blocks": [ + { + "bbox": [ + 85, + 124, + 495, + 264 + ], + "lines": [ + { + "bbox": [ + 85, + 124, + 495, + 264 + ], + "spans": [ + { + "bbox": [ + 85, + 124, + 495, + 264 + ], + "type": "image", + "image_path": "6a501db60794b36cfe20ab0dcdd885488c378fbbfc9395fcfe13273a8ad874fc.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 60, + 271, + 518, + 328 + ], + "lines": [ + { + "bbox": [ + 60, + 271, + 518, + 328 + ], + "spans": [ + { + "bbox": [ + 60, + 271, + 518, + 328 + ], + "type": "text", + "content": "Figure 1: ATM has two interdependent sets of optimization variables, model parameters and adversarial perturbations (yellow arrows), both of which contain nested training data influence (blue arrows). To remove such nested data influence, ATM unlearning requires the total Hessian that consists of both direct and indirect Hessian components (green solid lines). Existing unlearning methods designed for standard training models are inapplicable to ATM unlearning, because they only use direct Hessian information during the unlearning update and do not capture sufficient data influence (red dashed lines)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 60, + 346, + 282, + 444 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 346, + 282, + 444 + ], + "spans": [ + { + "bbox": [ + 60, + 346, + 282, + 444 + ], + "type": "text", + "content": "sarial examples into the training process. ATM is trained by a bi-level optimization with the model parameters as the outer-level variable and the adversarial perturbations as the inner-level variable. To the best of our knowledge, all existing unlearning methods focus solely on data removal from STM. As our analysis will reveal in Section 3, the existing methods cannot be applied to ATM unlearning without miscapturing the data influence to be removed, due to ATM's bi-level optimization structure." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 60, + 448, + 282, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 448, + 282, + 712 + ], + "spans": [ + { + "bbox": [ + 60, + 448, + 282, + 712 + ], + "type": "text", + "content": "In this paper, we propose a new unlearning approach called MUt e r: M Machine Unlearning for data removal from adversarial training models. First, we define the ATM unlearning task in accordance with the mainstream machine unlearning standard. Second, we convert it to an ATM unlearning criteria derived from the optimality condition of ATM, which facilitates the derivation of the unlearning update for ATM. Meanwhile, existing unlearning methods designed for STM cannot satisfy the ATM unlearning criteria. As illustrated in Figure 1, ATM, as a bi-level optimization, has two sets of variables: model parameters and adversarial perturbations, which are interdependent and both contain training data information. In contrast, STM, as a single-level optimization, has only one set of variables: model parameters, which have a direct influence dependence on each training datapoint. Existing unlearning methods cannot sufficiently remove data influence from ATM because they fail to account for the indirect influence on the model parameters (i.e., miss the indirect Hessian part in Figure 1). That is, due to the coupled outer-inner optimization, any updates to the outer model parameters will incur further updates for both the adversarial perturbations and the model parameters. To address this, we derive a new closed-form unlearning update for ATM, which is underpinned by the total Hessian-based" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 296, + 346, + 518, + 432 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 346, + 518, + 432 + ], + "spans": [ + { + "bbox": [ + 296, + 346, + 518, + 432 + ], + "type": "text", + "content": "influence measure. Third, based on the ATM unlearning update, we propose a three-stage unlearning framework to support successive unlearning requests for ATM, which enhances efficiency by selectively storing certain computations in memory. Last, we leverage Schur complement conversion and Neumann series approximation to avoid the computationally demanding and numerical unstable computations of Hessian matrix and its inversions." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 308, + 434, + 467, + 443 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 434, + 467, + 443 + ], + "spans": [ + { + "bbox": [ + 308, + 434, + 467, + 443 + ], + "type": "text", + "content": "To summarize, our main contributions are:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 296, + 444, + 518, + 641 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 296, + 444, + 517, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 444, + 517, + 498 + ], + "spans": [ + { + "bbox": [ + 296, + 444, + 517, + 498 + ], + "type": "text", + "content": "1. We introduce the problem of unlearning from adversarial training models, which is a new and pressing challenge to simultaneously meet emerging privacy regulations and ensure the adversarial robustness of the model. To the best of our knowledge, it has not been studied in the existing literature." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 296, + 499, + 518, + 542 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 499, + 518, + 542 + ], + "spans": [ + { + "bbox": [ + 296, + 499, + 518, + 542 + ], + "type": "text", + "content": "2. We derive a new unlearning update tailored to ATM unlearning, which has the total Hessian-based data influence measure to sufficiently account for the interdependence between inner and outer optimizations of ATM." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 296, + 542, + 518, + 596 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 542, + 518, + 596 + ], + "spans": [ + { + "bbox": [ + 296, + 542, + 518, + 596 + ], + "type": "text", + "content": "3. We propose MUt er based on the proposed unlearning update, which supports successive unlearning requests for ATM and introduces a series of conversions and approximations for Hessian inversions to alleviate the computational cost and improve the numerical stability." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 296, + 597, + 518, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 597, + 518, + 641 + ], + "spans": [ + { + "bbox": [ + 296, + 597, + 518, + 641 + ], + "type": "text", + "content": "4. We perform a comprehensive evaluation to verify that " + }, + { + "bbox": [ + 296, + 597, + 518, + 641 + ], + "type": "inline_equation", + "content": "MUter" + }, + { + "bbox": [ + 296, + 597, + 518, + 641 + ], + "type": "text", + "content": " achieves effective and efficient unlearning performance while maintaining the model accuracy and adversarial robustness, under two unlearning settings on four datasets." + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 297, + 650, + 463, + 662 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 650, + 463, + 662 + ], + "spans": [ + { + "bbox": [ + 297, + 650, + 463, + 662 + ], + "type": "text", + "content": "2. Preliminaries and Related Work" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 297, + 669, + 402, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 669, + 402, + 682 + ], + "spans": [ + { + "bbox": [ + 297, + 669, + 402, + 682 + ], + "type": "text", + "content": "2.1. Setup and Notation" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 688, + 518, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 688, + 518, + 712 + ], + "spans": [ + { + "bbox": [ + 296, + 688, + 518, + 712 + ], + "type": "text", + "content": "Setup. Denote the training dataset with " + }, + { + "bbox": [ + 296, + 688, + 518, + 712 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 296, + 688, + 518, + 712 + ], + "type": "text", + "content": " training samples by " + }, + { + "bbox": [ + 296, + 688, + 518, + 712 + ], + "type": "inline_equation", + "content": "\\mathcal{D} = \\{(\\mathbf{x}_1,y_1),\\ldots ,(\\mathbf{x}_n,y_n)\\}" + }, + { + "bbox": [ + 296, + 688, + 518, + 712 + ], + "type": "text", + "content": " , where for " + }, + { + "bbox": [ + 296, + 688, + 518, + 712 + ], + "type": "inline_equation", + "content": "\\forall i\\in" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "spans": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "text", + "content": "4893" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "spans": [ + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "inline_equation", + "content": "\\{1,\\dots ,n\\}" + }, + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "inline_equation", + "content": "\\mathbf{x}_i\\in \\mathbb{R}^d" + }, + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "text", + "content": " is the " + }, + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "text", + "content": " -dimensional feature vector, and " + }, + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "inline_equation", + "content": "y_{i}\\in \\mathbb{R}" + }, + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "text", + "content": " is the corresponding response/label. Denote the loss function by " + }, + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "inline_equation", + "content": "l(\\omega ,\\mathbf{x}_i)" + }, + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "text", + "content": " , where " + }, + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "inline_equation", + "content": "\\omega \\in \\mathbb{R}^p" + }, + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "text", + "content": " represents the vector of the " + }, + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 60, + 124, + 280, + 170 + ], + "type": "text", + "content": " -dimensional model parameters." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 60, + 172, + 281, + 216 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 172, + 281, + 216 + ], + "spans": [ + { + "bbox": [ + 60, + 172, + 281, + 216 + ], + "type": "text", + "content": "Standard Training Model (STM). Standard training model refers to the empirical risk minimization model: " + }, + { + "bbox": [ + 60, + 172, + 281, + 216 + ], + "type": "inline_equation", + "content": "\\omega_{std}^{*} = \\mathrm{argmin}_{\\omega}\\frac{1}{n}\\sum_{i = 1}^{n}l(\\omega ,\\mathbf{x}_i)" + }, + { + "bbox": [ + 60, + 172, + 281, + 216 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 60, + 172, + 281, + 216 + ], + "type": "inline_equation", + "content": "\\omega \\in \\mathbb{R}^p" + }, + { + "bbox": [ + 60, + 172, + 281, + 216 + ], + "type": "text", + "content": " is the model parameter variable." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 60, + 218, + 281, + 271 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 218, + 281, + 271 + ], + "spans": [ + { + "bbox": [ + 60, + 218, + 281, + 271 + ], + "type": "text", + "content": "Adversarial Training Model (ATM). Adversarial training model is an effective defense against robustness threats posed by the adversarial attack. In this paper, we adopt one of the most widely-used ATM variants to consider the following bi-level robust optimization formulation [30, 50]," + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 91, + 278, + 281, + 303 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 278, + 281, + 303 + ], + "spans": [ + { + "bbox": [ + 91, + 278, + 281, + 303 + ], + "type": "interline_equation", + "content": "\\boldsymbol {\\omega} ^ {*} = \\underset {\\boldsymbol {\\omega}} {\\operatorname {a r g m i n}} \\frac {1}{n} \\sum_ {i = 1} ^ {n} \\max _ {\\delta_ {i} \\in \\mathcal {B} (\\mathbf {x} _ {i}, r)} l (\\boldsymbol {\\omega}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i}), \\tag {1}", + "image_path": "4b6a511fb6a30e38d3ef75205062cfcebb97f25b6da3955efa23c8a950e09224.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "spans": [ + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "text", + "content": "where the inner optimization is to find adversarial perturbation " + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "inline_equation", + "content": "\\delta_{i}" + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "text", + "content": " from the constraint set " + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "inline_equation", + "content": "\\mathcal{B}(\\mathbf{x}_i,r)" + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "text", + "content": " to maximize the loss and the outer optimization is to find the model parameter " + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "inline_equation", + "content": "\\omega" + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "text", + "content": " that minimizes the loss for the adversarially perturbed examples. To make the interdependence between the outer variable " + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "inline_equation", + "content": "\\omega" + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "text", + "content": " and the inner variable " + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "inline_equation", + "content": "\\delta" + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "text", + "content": " more explicit, we further introduce an auxiliary function " + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "inline_equation", + "content": "\\delta_{i}(\\omega)" + }, + { + "bbox": [ + 60, + 311, + 281, + 383 + ], + "type": "text", + "content": " given by" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 111, + 390, + 281, + 409 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 390, + 281, + 409 + ], + "spans": [ + { + "bbox": [ + 111, + 390, + 281, + 409 + ], + "type": "interline_equation", + "content": "\\delta_ {i} (\\boldsymbol {\\omega}) = \\underset {\\boldsymbol {\\delta} _ {i} \\in \\mathcal {B} (\\mathbf {x} _ {i}, r)} {\\operatorname {a r g m a x}} l \\left(\\boldsymbol {\\omega}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i}\\right). \\tag {2}", + "image_path": "0edb8c78393acc878d0a50e3ba8aea6dd4b0a97476f615bc256a1c162377aa7d.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 60, + 419, + 281, + 497 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 419, + 281, + 497 + ], + "spans": [ + { + "bbox": [ + 60, + 419, + 281, + 497 + ], + "type": "text", + "content": "Machine Unlearning for Adversarial Training Models. Definition 1 below specifies the ATM unlearning task in consistency with the mainstream unlearning standard. For notational simplicity, we focus on single-point removal in the paper, but the analysis and algorithms developed in the paper are generalizable to batch removal as well (please refer to Appendix B.5 for the batch removal generalization)." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 60, + 504, + 281, + 556 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 504, + 281, + 556 + ], + "spans": [ + { + "bbox": [ + 60, + 504, + 281, + 556 + ], + "type": "text", + "content": "Definition 1. (Machine Unlearning for Adversarial Training Models) For a trained adversarial training model as in eq.(1), let " + }, + { + "bbox": [ + 60, + 504, + 281, + 556 + ], + "type": "inline_equation", + "content": "\\forall i^{\\dagger}\\in \\{1,\\dots ,n\\}" + }, + { + "bbox": [ + 60, + 504, + 281, + 556 + ], + "type": "text", + "content": " be the index of a datapoint to be forgotten. The ATM after machine unlearning unlearning (forgetting datapoint " + }, + { + "bbox": [ + 60, + 504, + 281, + 556 + ], + "type": "inline_equation", + "content": "i^{\\dagger}" + }, + { + "bbox": [ + 60, + 504, + 281, + 556 + ], + "type": "text", + "content": ") has parameter " + }, + { + "bbox": [ + 60, + 504, + 281, + 556 + ], + "type": "inline_equation", + "content": "\\omega_{-i^{\\dagger}}^{*}" + }, + { + "bbox": [ + 60, + 504, + 281, + 556 + ], + "type": "text", + "content": " as follows," + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 69, + 565, + 281, + 591 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 565, + 281, + 591 + ], + "spans": [ + { + "bbox": [ + 69, + 565, + 281, + 591 + ], + "type": "interline_equation", + "content": "\\omega_ {- i ^ {\\dagger}} ^ {*} = \\underset {\\omega} {\\operatorname {a r g m i n}} \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\max _ {\\delta_ {i} \\in \\mathcal {B} (\\mathbf {x} _ {i}, r)} l (\\omega , \\mathbf {x} _ {i} + \\delta_ {i}). \\tag {3}", + "image_path": "14d392d789cfc54a7cceac94f7a66f6e9d22bf40eb668dbaaffcb314334e7c3d.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 60, + 600, + 281, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 600, + 281, + 677 + ], + "spans": [ + { + "bbox": [ + 60, + 600, + 281, + 677 + ], + "type": "text", + "content": "Retraining-from-scratch serves as the golden standard and also a naive baseline to obtain the unlearned ATM " + }, + { + "bbox": [ + 60, + 600, + 281, + 677 + ], + "type": "inline_equation", + "content": "\\omega_{-i\\dagger}^{*}" + }, + { + "bbox": [ + 60, + 600, + 281, + 677 + ], + "type": "text", + "content": ", which is prohibitive in computation, especially for ATM with both inner maximization and outer minimization. Hence, the goal of machine unlearning for ATM is to approximately remove " + }, + { + "bbox": [ + 60, + 600, + 281, + 677 + ], + "type": "inline_equation", + "content": "i^{\\dagger}" + }, + { + "bbox": [ + 60, + 600, + 281, + 677 + ], + "type": "text", + "content": "'s influence with great computational efficiency improvement over retraining-from-scratch." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "spans": [ + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "text", + "content": "Notation. For a twice differentiable " + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "inline_equation", + "content": "l(\\omega, \\mathbf{x} + \\delta)" + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "inline_equation", + "content": "\\nabla_{\\omega} l(\\omega, \\mathbf{x} + \\delta)" + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "text", + "content": " denotes the direct gradient of " + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "text", + "content": " with respect to (w.r.t.) " + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "inline_equation", + "content": "\\omega" + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "inline_equation", + "content": "\\partial_{\\omega \\omega} l(\\omega, \\mathbf{x} + \\delta)" + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "inline_equation", + "content": "\\partial_{\\omega \\delta} l(\\omega, \\mathbf{x} + \\delta)" + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "inline_equation", + "content": "\\partial_{\\delta \\omega} l(\\omega, \\mathbf{x} + \\delta)" + }, + { + "bbox": [ + 60, + 679, + 281, + 712 + ], + "type": "text", + "content": "," + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 125, + 516, + 146 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 125, + 516, + 146 + ], + "spans": [ + { + "bbox": [ + 296, + 125, + 516, + 146 + ], + "type": "inline_equation", + "content": "\\partial_{\\delta \\delta}l(\\omega ,\\mathbf{x} + \\delta)" + }, + { + "bbox": [ + 296, + 125, + 516, + 146 + ], + "type": "text", + "content": " denote the second order partial derivatives w.r.t. " + }, + { + "bbox": [ + 296, + 125, + 516, + 146 + ], + "type": "inline_equation", + "content": "\\omega" + }, + { + "bbox": [ + 296, + 125, + 516, + 146 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 296, + 125, + 516, + 146 + ], + "type": "inline_equation", + "content": "\\delta" + }, + { + "bbox": [ + 296, + 125, + 516, + 146 + ], + "type": "text", + "content": " , correspondingly. The total Hessian is" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 297, + 154, + 516, + 187 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 154, + 516, + 187 + ], + "spans": [ + { + "bbox": [ + 297, + 154, + 516, + 187 + ], + "type": "interline_equation", + "content": "\\mathrm {D} _ {\\omega \\omega} l (\\omega , \\mathbf {x} + \\delta) := \\overbrace {\\partial_ {\\omega \\omega} l (\\omega , \\mathbf {x} + \\delta)} ^ {\\text {D i r e c t H e s s i a n}} - \\overbrace {\\partial_ {\\omega \\delta} \\partial_ {\\delta \\delta} ^ {- 1} \\partial_ {\\delta \\omega} l (\\omega , \\mathbf {x} + \\delta)} ^ {\\text {I n d i r e c t H e s s i a n}}, \\tag {4}", + "image_path": "4c846632fd1abd0b798b89eafcc4e5f89584e5a354753f102c33eb4537640fe1.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 187, + 517, + 233 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 187, + 517, + 233 + ], + "spans": [ + { + "bbox": [ + 296, + 187, + 517, + 233 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 296, + 187, + 517, + 233 + ], + "type": "inline_equation", + "content": "\\partial_{\\omega \\delta}\\partial_{\\delta \\delta}^{-1}\\partial_{\\delta \\omega}l(\\omega ,\\mathbf{x} + \\boldsymbol {\\delta}) = \\partial_{\\omega \\delta}l(\\omega ,\\mathbf{x} + \\boldsymbol {\\delta})(\\partial_{\\delta \\delta}l(\\omega ,\\mathbf{x} + \\boldsymbol {\\delta}))^{-1}\\partial_{\\delta \\omega}l(\\omega ,\\mathbf{x} + \\boldsymbol {\\delta})" + }, + { + "bbox": [ + 296, + 187, + 517, + 233 + ], + "type": "text", + "content": " .We also use the short hand notation " + }, + { + "bbox": [ + 296, + 187, + 517, + 233 + ], + "type": "inline_equation", + "content": "l_i^*\\coloneqq l(\\pmb {\\omega}^*,\\mathbf{x}_i + \\delta_i(\\pmb {\\omega}^*))" + }, + { + "bbox": [ + 296, + 187, + 517, + 233 + ], + "type": "text", + "content": " and similarly introduce " + }, + { + "bbox": [ + 296, + 187, + 517, + 233 + ], + "type": "inline_equation", + "content": "\\nabla_{\\omega}l_{i}^{*},\\partial_{\\omega \\omega}l_{i}^{*},\\partial_{\\omega \\delta}l_{i}^{*},\\partial_{\\delta \\omega}l_{i}^{*},\\partial_{\\delta \\delta}l_{i}^{*}" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 298, + 239, + 377, + 250 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 239, + 377, + 250 + ], + "spans": [ + { + "bbox": [ + 298, + 239, + 377, + 250 + ], + "type": "text", + "content": "2.2. Related Work" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 296, + 256, + 517, + 345 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 256, + 517, + 345 + ], + "spans": [ + { + "bbox": [ + 296, + 256, + 517, + 345 + ], + "type": "text", + "content": "We briefly review existing machine unlearning methods. They are exclusively focused on STM and are not applicable to ATM unlearning with sufficient data influence removal. We provide a brief overview of current machine unlearning methods, which are focused exclusively on unlearning for STM and are not applicable to ATM unlearning with sufficient data influence removal. Thus, it is necessary to develop a new unlearning approach specific to ATM unlearning." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 296, + 346, + 517, + 511 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 346, + 517, + 511 + ], + "spans": [ + { + "bbox": [ + 296, + 346, + 517, + 511 + ], + "type": "text", + "content": "Exact Machine Unlearning. Exact unlearning methods perform exact retraining but manage to do so only on a selective portion of the dataset to avoid retraining on the entire dataset. Some exact unlearning methods are designed for specific models like Naive Bayes [8], quantized k-means [19], and random forests [6]. Recently, SISA [5] proposes a more general exact unlearning strategy. It divides the training data into multiple disjoint shards during the training phase, and retransmits only on the shard that contains the data to be removed during the unlearning phase. Later, [11] and [12] extend the SISA strategy to unlearning for recommendation systems and graph neural networks. However, the SISA strategy requires different shards to be independently updatable from each other, which is not the case for ATM due to its interdependent bi-level structure." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 296, + 514, + 517, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 514, + 517, + 712 + ], + "spans": [ + { + "bbox": [ + 296, + 514, + 517, + 712 + ], + "type": "text", + "content": "Approximate Machine Unlearning. Approximate unlearning methods seek the updated model parameters to approximately satisfy the optimality condition of the objective function on the remaining data, which can be roughly divided into three categories. 1) Unlearning with direct Hessian-related terms: [22, 26, 31, 34, 40, 43, 49] propose Newton step-based unlearning updates, where the Newton curvature matrices are direct Hessian-related terms. These methods also inject Gaussian noise to further destroy the remaining data influence due to the discrepancy between the exact unlearning standard and the approximate unlearning criteria. Some works also consider to alleviate the computational cost of the Hessian. For example, [22] proposes to approximate the direct Hessian with Fisher information matrix; [43] proposes to avoid dealing with the entire direct Hessian by selecting small Hessian blocks for unlearning update. 2) Unlearning based on neural tangent kernel (NTK) theory: they approximates the training phase by NTK theory, where [23] regards" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "spans": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "text", + "content": "4894" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 60, + 125, + 282, + 257 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 125, + 282, + 257 + ], + "spans": [ + { + "bbox": [ + 60, + 125, + 282, + 257 + ], + "type": "text", + "content": "the training as an approximately linear change and [21] divides the training phase into two stages, one is the linear standard training on the core dataset, and the other is the linear finetuning on the target dataset. Both works then apply direct Hessian-related unlearning updates. 3) Unlearning by tracking the Stochastic Gradient Descent (SGD) path during training: DeltaGrad [60] and unrollSGD [57] propose to track and reverse the SGD optimization path during the training phase. However, all above methods do not consider the interdependence between model parameters and adversarial perturbations of ATM, which cannot holistically capture the data influence, as will be detailed in the next section." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 61, + 265, + 208, + 277 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 265, + 208, + 277 + ], + "spans": [ + { + "bbox": [ + 61, + 265, + 208, + 277 + ], + "type": "text", + "content": "3. Unlearning Update for ATM" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 60, + 285, + 281, + 319 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 285, + 281, + 319 + ], + "spans": [ + { + "bbox": [ + 60, + 285, + 281, + 319 + ], + "type": "text", + "content": "ATM Unlearning Criteria. We begin by converting eq.(3) in Definition 1 to the optimality condition form of ATM based on Danskin's Theorem [13]," + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 95, + 323, + 281, + 353 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 95, + 323, + 281, + 353 + ], + "spans": [ + { + "bbox": [ + 95, + 323, + 281, + 353 + ], + "type": "interline_equation", + "content": "\\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\nabla_ {\\omega} l \\left(\\omega_ {- i ^ {\\dagger}} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\omega_ {- i ^ {\\dagger}} ^ {*}\\right)\\right) = 0, \\tag {5}", + "image_path": "b0c0bb901baca4c2ccce651dac5f613f8afedc9c674f6ea5ffdf225470d3ae74.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 60, + 357, + 282, + 414 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 357, + 282, + 414 + ], + "spans": [ + { + "bbox": [ + 60, + 357, + 282, + 414 + ], + "type": "text", + "content": "which provides more convenience to the follow-up ATM unlearning designs. Our goal is to find a closed-form unlearning update " + }, + { + "bbox": [ + 60, + 357, + 282, + 414 + ], + "type": "inline_equation", + "content": "\\mathcal{U}(\\boldsymbol{\\omega}^*, i^\\dagger)" + }, + { + "bbox": [ + 60, + 357, + 282, + 414 + ], + "type": "text", + "content": " such that the unlearning model with parameter " + }, + { + "bbox": [ + 60, + 357, + 282, + 414 + ], + "type": "inline_equation", + "content": "\\boldsymbol{\\omega}^u = \\boldsymbol{\\omega}^* + \\mathcal{U}(\\boldsymbol{\\omega}^*, i^\\dagger)" + }, + { + "bbox": [ + 60, + 357, + 282, + 414 + ], + "type": "text", + "content": " will satisfy the following ATM unlearning criteria," + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 102, + 417, + 281, + 448 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 102, + 417, + 281, + 448 + ], + "spans": [ + { + "bbox": [ + 102, + 417, + 281, + 448 + ], + "type": "interline_equation", + "content": "\\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\nabla_ {\\omega} l \\left(\\omega^ {u}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\omega^ {u}\\right)\\right) \\approx 0. \\tag {6}", + "image_path": "80b2a5e31e2977fd74773f83113e0fc59723bd5b91c413c3d1414bee1becf943.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 60, + 452, + 282, + 547 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 452, + 282, + 547 + ], + "spans": [ + { + "bbox": [ + 60, + 452, + 282, + 547 + ], + "type": "text", + "content": "Cause of Inapplicability of Existing Approximate Unlearning Methods. Before deriving our ATM unlearning update, we recall the design rationale common to existing approximate machine unlearning methods and point out why they fail to sufficiently remove the data influence for ATM. Despite the varying forms of specific unlearning updates, existing approximate unlearning methods all exploit the trained model parameter " + }, + { + "bbox": [ + 60, + 452, + 282, + 547 + ], + "type": "inline_equation", + "content": "\\omega^{*}" + }, + { + "bbox": [ + 60, + 452, + 282, + 547 + ], + "type": "text", + "content": " and connect it with the unlearned model " + }, + { + "bbox": [ + 60, + 452, + 282, + 547 + ], + "type": "inline_equation", + "content": "\\omega^{u}" + }, + { + "bbox": [ + 60, + 452, + 282, + 547 + ], + "type": "text", + "content": " by first-order expansion of " + }, + { + "bbox": [ + 60, + 452, + 282, + 547 + ], + "type": "inline_equation", + "content": "\\nabla_{\\omega}l" + }, + { + "bbox": [ + 60, + 452, + 282, + 547 + ], + "type": "text", + "content": " around " + }, + { + "bbox": [ + 60, + 452, + 282, + 547 + ], + "type": "inline_equation", + "content": "\\omega^{*}" + }, + { + "bbox": [ + 60, + 452, + 282, + 547 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 97, + 551, + 281, + 623 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 97, + 551, + 281, + 623 + ], + "spans": [ + { + "bbox": [ + 97, + 551, + 281, + 623 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\nabla_ {\\omega} l \\left(\\omega^ {u}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\omega^ {u}\\right)\\right) \\\\ \\approx \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\left[ \\nabla_ {\\omega} l \\left(\\omega^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\omega^ {u}\\right)\\right) \\right. \\tag {7} \\\\ \\left. + \\partial_ {\\omega} \\omega l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {u}\\right)\\right) \\left(\\boldsymbol {\\omega} ^ {u} - \\boldsymbol {\\omega} ^ {*}\\right) \\right]. \\\\ \\end{array}", + "image_path": "e5a5640b9c9885579b8154ed3783e86f84da0499e0373da2e6ff2cfa17308e4b.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 60, + 625, + 282, + 667 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 625, + 282, + 667 + ], + "spans": [ + { + "bbox": [ + 60, + 625, + 282, + 667 + ], + "type": "text", + "content": "Existing methods then obtain the updated " + }, + { + "bbox": [ + 60, + 625, + 282, + 667 + ], + "type": "inline_equation", + "content": "\\omega^u" + }, + { + "bbox": [ + 60, + 625, + 282, + 667 + ], + "type": "text", + "content": " by letting the right hand side of eq.(7) approach 0 and exploiting the optimality condition of " + }, + { + "bbox": [ + 60, + 625, + 282, + 667 + ], + "type": "inline_equation", + "content": "\\omega^{*}" + }, + { + "bbox": [ + 60, + 625, + 282, + 667 + ], + "type": "text", + "content": ". For example, the influence function-inspired unlearning [26, 49] has " + }, + { + "bbox": [ + 60, + 625, + 282, + 667 + ], + "type": "inline_equation", + "content": "\\mathbf{u}(\\boldsymbol{\\omega}^{*}, i^{\\dagger}) =" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 63, + 671, + 281, + 711 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 671, + 281, + 711 + ], + "spans": [ + { + "bbox": [ + 63, + 671, + 281, + 711 + ], + "type": "interline_equation", + "content": "\\left[ \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\underbrace {\\partial_ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {u}\\right)\\right)} _ {\\text {D i r e c t H e s s i a n - o n l y}} \\right] ^ {- 1} \\nabla_ {\\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\delta_ {i ^ {\\dagger}} \\left(\\boldsymbol {\\omega} ^ {u}\\right)\\right). \\tag {8}", + "image_path": "0b7f4531da23a4a69b76cb6dcd4809addf7fe0501c142563a28b65cfba80c31a.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "spans": [ + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "text", + "content": "However, there are two obvious issues when applying the above design rationale to the ATM unlearning: 1) the conversion from eq.(7) to eq.(8) requires " + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "inline_equation", + "content": "\\sum_{i=1}^{n} \\nabla_{\\omega} l(\\omega^{*}, \\mathbf{x}_{i} + \\delta_{i}(\\omega^{u})) = 0" + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "text", + "content": ", which does not hold in general. Rather, the optimality condition only promises " + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "inline_equation", + "content": "\\sum_{i=1}^{n} \\nabla_{\\omega} l(\\omega^{*}, \\mathbf{x}_{i} + \\delta_{i}(\\omega^{*})) = 0" + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "text", + "content": "; 2) the Hessian " + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "inline_equation", + "content": "\\partial_{\\omega \\omega} l(\\omega^{*}, \\mathbf{x}_{i} + \\delta_{i}(\\omega^{u}))" + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "text", + "content": " and gradient " + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "inline_equation", + "content": "\\nabla_{\\omega} l(\\omega^{*}, \\mathbf{x}_{i} + \\delta_{i}(\\omega^{u}))" + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "text", + "content": " in eq.(8) are not commutable without knowing " + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "inline_equation", + "content": "\\omega^{u}" + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "text", + "content": " in advance. We point out that the root cause of both issues is that eq.(7) fails to account for the interdependence between " + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "inline_equation", + "content": "\\omega" + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "inline_equation", + "content": "\\delta" + }, + { + "bbox": [ + 296, + 125, + 518, + 234 + ], + "type": "text", + "content": " as in eq.(2)." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 237, + 518, + 303 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 237, + 518, + 303 + ], + "spans": [ + { + "bbox": [ + 296, + 237, + 518, + 303 + ], + "type": "text", + "content": "Proposed ATM Unlearning Update. The above root cause propels us to derive a new unlearning update that can holistically capture the nested data influence. To account for the interdependence between the adversarial perturbations and the model parameters in eq.(2), we take the complete expansion w.r.t. both " + }, + { + "bbox": [ + 296, + 237, + 518, + 303 + ], + "type": "inline_equation", + "content": "\\omega" + }, + { + "bbox": [ + 296, + 237, + 518, + 303 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 296, + 237, + 518, + 303 + ], + "type": "inline_equation", + "content": "\\delta" + }, + { + "bbox": [ + 296, + 237, + 518, + 303 + ], + "type": "text", + "content": " as in Lemma 1 below." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 296, + 309, + 518, + 343 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 309, + 518, + 343 + ], + "spans": [ + { + "bbox": [ + 296, + 309, + 518, + 343 + ], + "type": "text", + "content": "Lemma 1. By expansion around both " + }, + { + "bbox": [ + 296, + 309, + 518, + 343 + ], + "type": "inline_equation", + "content": "\\omega^{*}" + }, + { + "bbox": [ + 296, + 309, + 518, + 343 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 296, + 309, + 518, + 343 + ], + "type": "inline_equation", + "content": "\\delta (\\omega^{*})" + }, + { + "bbox": [ + 296, + 309, + 518, + 343 + ], + "type": "text", + "content": ", the approximate machine unlearning model parameter " + }, + { + "bbox": [ + 296, + 309, + 518, + 343 + ], + "type": "inline_equation", + "content": "\\omega^u" + }, + { + "bbox": [ + 296, + 309, + 518, + 343 + ], + "type": "text", + "content": " and the original model parameter " + }, + { + "bbox": [ + 296, + 309, + 518, + 343 + ], + "type": "inline_equation", + "content": "\\omega^{*}" + }, + { + "bbox": [ + 296, + 309, + 518, + 343 + ], + "type": "text", + "content": " has the following relation," + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 308, + 349, + 517, + 447 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 349, + 517, + 447 + ], + "spans": [ + { + "bbox": [ + 308, + 349, + 517, + 447 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\nabla_ {\\boldsymbol {\\omega}} l (\\boldsymbol {\\omega} ^ {u}, \\mathbf {x} _ {i} + \\delta_ {i} (\\boldsymbol {\\omega} ^ {u})) \\\\ \\approx \\frac {1}{n - 1} \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\left[ \\nabla_ {\\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {*}\\right)\\right) \\right. \\tag {9} \\\\ + \\partial_ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {*}\\right)\\right) \\left(\\boldsymbol {\\omega} ^ {u} - \\boldsymbol {\\omega} ^ {*}\\right) \\\\ \\left. + \\partial_ {\\boldsymbol {\\omega} \\delta} l (\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\delta_ {i} (\\boldsymbol {\\omega} ^ {*})) (\\delta_ {i} (\\boldsymbol {\\omega} ^ {u}) - \\delta_ {i} (\\boldsymbol {\\omega} ^ {*})) \\right]. \\\\ \\end{array}", + "image_path": "9a6e5920bdbb39d0dce6792d30ad320621f713a848b9c53f52e40ce4e5fee661.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 297, + 452, + 435, + 463 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 452, + 435, + 463 + ], + "spans": [ + { + "bbox": [ + 297, + 452, + 435, + 463 + ], + "type": "text", + "content": "Proof. Please refer to Appendix B.1." + } + ] + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 507, + 453, + 517, + 461 + ], + "blocks": [ + { + "bbox": [ + 507, + 453, + 517, + 461 + ], + "lines": [ + { + "bbox": [ + 507, + 453, + 517, + 461 + ], + "spans": [ + { + "bbox": [ + 507, + 453, + 517, + 461 + ], + "type": "image", + "image_path": "abb4a22bf9055ecd5bb11fdbd33969e720f11b20a9d7d7d195b6294f72c87c1c.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + } + ], + "index": 15 + }, + { + "bbox": [ + 296, + 470, + 518, + 526 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 470, + 518, + 526 + ], + "spans": [ + { + "bbox": [ + 296, + 470, + 518, + 526 + ], + "type": "text", + "content": "The last line of eq.(9) is key to the sufficient removal of the data influence from ATM, which captures the interdependence between the adversarial perturbations and the model parameters. Based on Lemma 1, we can derive the ATM unlearning update in closed-form in Theorem 1 below." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 296, + 530, + 518, + 573 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 530, + 518, + 573 + ], + "spans": [ + { + "bbox": [ + 296, + 530, + 518, + 573 + ], + "type": "text", + "content": "Theorem 1. Consider the adversarial training model with trained model parameter " + }, + { + "bbox": [ + 296, + 530, + 518, + 573 + ], + "type": "inline_equation", + "content": "\\omega^{*}" + }, + { + "bbox": [ + 296, + 530, + 518, + 573 + ], + "type": "text", + "content": " as in eq.(1). Let " + }, + { + "bbox": [ + 296, + 530, + 518, + 573 + ], + "type": "inline_equation", + "content": "(\\mathbf{x}_{i^{\\dagger}},y_{i^{\\dagger}})" + }, + { + "bbox": [ + 296, + 530, + 518, + 573 + ], + "type": "text", + "content": " be a datapoint in the training dataset to be forgotten. Let the machine learning update " + }, + { + "bbox": [ + 296, + 530, + 518, + 573 + ], + "type": "inline_equation", + "content": "\\mathcal{U}(\\boldsymbol {\\omega}^*,i^{\\dagger})" + }, + { + "bbox": [ + 296, + 530, + 518, + 573 + ], + "type": "text", + "content": " take the following form" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 312, + 578, + 517, + 627 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 578, + 517, + 627 + ], + "spans": [ + { + "bbox": [ + 312, + 578, + 517, + 627 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {U} \\left(\\boldsymbol {\\omega} ^ {*}, i ^ {\\dagger}\\right) := \\left[ \\sum_ {i = 1, i \\neq i ^ {\\dagger}} ^ {n} \\underbrace {\\mathrm {D} _ {\\boldsymbol {\\omega} \\boldsymbol {\\omega}} l \\left(\\boldsymbol {\\omega} ^ {*} , \\mathbf {x} _ {i} + \\delta_ {i} \\left(\\boldsymbol {\\omega} ^ {*}\\right)\\right)} _ {\\text {T o t a l H e s s i a n}} \\right] ^ {- 1} \\tag {10} \\\\ \\cdot \\left[ \\nabla_ {\\boldsymbol {\\omega}} l (\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\delta_ {i ^ {\\dagger}} (\\boldsymbol {\\omega} ^ {*})) \\right]. \\\\ \\end{array}", + "image_path": "35e74dbfbcafc2737a28382e5edc4e3bcf1c5d4b8e9c3cf6458e3f3c4b2034ea.jpg" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 296, + 631, + 518, + 666 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 631, + 518, + 666 + ], + "spans": [ + { + "bbox": [ + 296, + 631, + 518, + 666 + ], + "type": "text", + "content": "Then, the unlearning model with updated parameters " + }, + { + "bbox": [ + 296, + 631, + 518, + 666 + ], + "type": "inline_equation", + "content": "\\omega^u \\coloneqq \\omega^* + \\mathcal{U}(\\omega^*, i^\\dagger)" + }, + { + "bbox": [ + 296, + 631, + 518, + 666 + ], + "type": "text", + "content": " satisfies the approximate unlearning criteria for the adversarial training model in eq.(6)." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 297, + 671, + 436, + 682 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 671, + 436, + 682 + ], + "spans": [ + { + "bbox": [ + 297, + 671, + 436, + 682 + ], + "type": "text", + "content": "Proof. Please refer to Appendix B.1." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 296, + 688, + 518, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 688, + 518, + 711 + ], + "spans": [ + { + "bbox": [ + 296, + 688, + 518, + 711 + ], + "type": "text", + "content": "It turns out that the ATM unlearning in eq.(10) requires both direct Hessian and indirect Hessian (i.e., total Hessian" + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "spans": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "text", + "content": "4895" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 60, + 125, + 281, + 181 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 125, + 281, + 181 + ], + "spans": [ + { + "bbox": [ + 60, + 125, + 281, + 181 + ], + "type": "text", + "content": "in eq.(4)) to sufficiently capture the data influence, while previous methods for the STM unlearning have only the direct Hessian-related part (e.g., eq.(8)). The total Hessian term also appears in the second-order bi-level optimization literature, e.g., the Complete Newton method in [64]." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 60, + 184, + 282, + 261 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 184, + 282, + 261 + ], + "spans": [ + { + "bbox": [ + 60, + 184, + 282, + 261 + ], + "type": "text", + "content": "A New Influence Function. Finally, we would like to remark that eq.(10) can be used to define a new influence function as follows to measure the nested data influence of a data point for ATM. It could serve as an independent interest, for example, to measure the marginal contribution of a data point to the model for valuation in data market [46] and influence-based defense against data poisoning attacks [18]." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 60, + 270, + 281, + 310 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 270, + 281, + 310 + ], + "spans": [ + { + "bbox": [ + 60, + 270, + 281, + 310 + ], + "type": "text", + "content": "Definition 2. (Leave-one-out Adversarial Influence Function) For the adversarial training model given in eq.(1), the leave-one-out adversarial influence function for any " + }, + { + "bbox": [ + 60, + 270, + 281, + 310 + ], + "type": "inline_equation", + "content": "(\\mathbf{x},y)" + }, + { + "bbox": [ + 60, + 270, + 281, + 310 + ], + "type": "text", + "content": " in the training dataset is defined as" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 63, + 319, + 277, + 345 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 319, + 277, + 345 + ], + "spans": [ + { + "bbox": [ + 63, + 319, + 277, + 345 + ], + "type": "interline_equation", + "content": "\\mathcal {I} (\\mathbf {x}, y) = - \\left[ \\frac {1}{n} \\sum_ {i = 1} ^ {n} \\mathrm {D} _ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i} ^ {*}\\right) \\right] ^ {- 1} \\nabla_ {\\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} + \\boldsymbol {\\delta} ^ {*}\\right).", + "image_path": "208e12bb0088760c44791839ce8474ef035a67cb435ce95be2497aabcba215d5.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 60, + 355, + 282, + 442 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 355, + 282, + 442 + ], + "spans": [ + { + "bbox": [ + 60, + 355, + 282, + 442 + ], + "type": "text", + "content": "Definition 2 utilizes total Hessian instead of direct Hessian-only as in [32], which captures the interdependence between adversarial perturbations and model parameters. This is different from recent work [14] which defines the adversarial influence function as a training sample's influence difference between two models: an STM and an ATM, while Definition 2 measures a training sample's influence difference when it is in or out for a single ATM." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 60, + 455, + 195, + 467 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 455, + 195, + 467 + ], + "spans": [ + { + "bbox": [ + 60, + 455, + 195, + 467 + ], + "type": "text", + "content": "4. Proposed Method: MUt er" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 60, + 474, + 280, + 595 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 474, + 280, + 595 + ], + "spans": [ + { + "bbox": [ + 60, + 474, + 280, + 595 + ], + "type": "text", + "content": "Equipped with the ATM unlearning update, we propose MUt er, a three-stage unlearning method for ATM, which has two design considerations: 1) Support the more practical successive unlearning setting where multiple data points can be forgotten in sequence by keeping a selective variable set in memory (Sec.4.1); 2) Reduce the per-unlearning computational cost by introducing more efficient approximations and conversions to avoid direct computations of the most computational demanding Hessian inversions (Sec.4.2). The overall framework of MUt er is illustrated in Figure 2. We also present the complete algorithm in Appendix B.4." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 60, + 603, + 175, + 615 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 603, + 175, + 615 + ], + "spans": [ + { + "bbox": [ + 60, + 603, + 175, + 615 + ], + "type": "text", + "content": "4.1. Three Stages of MUt er" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 60, + 624, + 281, + 682 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 624, + 281, + 682 + ], + "spans": [ + { + "bbox": [ + 60, + 624, + 281, + 682 + ], + "type": "text", + "content": "Successive Unlearning Setting. Denote the indices of datapoints that have already been forgotten at timestamp " + }, + { + "bbox": [ + 60, + 624, + 281, + 682 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 60, + 624, + 281, + 682 + ], + "type": "text", + "content": " by " + }, + { + "bbox": [ + 60, + 624, + 281, + 682 + ], + "type": "inline_equation", + "content": "\\{i_1^\\dagger, \\ldots, i_r^\\dagger\\}" + }, + { + "bbox": [ + 60, + 624, + 281, + 682 + ], + "type": "text", + "content": ", the index of datapoint to be forgotten at timestamp " + }, + { + "bbox": [ + 60, + 624, + 281, + 682 + ], + "type": "inline_equation", + "content": "r + 1" + }, + { + "bbox": [ + 60, + 624, + 281, + 682 + ], + "type": "text", + "content": " by " + }, + { + "bbox": [ + 60, + 624, + 281, + 682 + ], + "type": "inline_equation", + "content": "i_{r + 1}^\\dagger = i^\\dagger" + }, + { + "bbox": [ + 60, + 624, + 281, + 682 + ], + "type": "text", + "content": ". Corollary 1 below extends Theorem 1 to support successive unlearning for ATM." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 60, + 690, + 281, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 690, + 281, + 711 + ], + "spans": [ + { + "bbox": [ + 60, + 690, + 281, + 711 + ], + "type": "text", + "content": "Corollary 1. Considering the successive unlearning setting, let the machine unlearning update at the " + }, + { + "bbox": [ + 60, + 690, + 281, + 711 + ], + "type": "inline_equation", + "content": "r + 1" + }, + { + "bbox": [ + 60, + 690, + 281, + 711 + ], + "type": "text", + "content": "-th timestamp" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 297, + 124, + 437, + 137 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 124, + 437, + 137 + ], + "spans": [ + { + "bbox": [ + 297, + 124, + 437, + 137 + ], + "type": "inline_equation", + "content": "\\mathfrak{U}_r(\\omega^*, i_{r+1}^\\dagger)" + }, + { + "bbox": [ + 297, + 124, + 437, + 137 + ], + "type": "text", + "content": " take the following form" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 302, + 145, + 468, + 185 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 302, + 145, + 468, + 185 + ], + "spans": [ + { + "bbox": [ + 302, + 145, + 468, + 185 + ], + "type": "interline_equation", + "content": "\\mathcal {U} _ {r} \\left(\\boldsymbol {\\omega} ^ {*}, i _ {r + 1} ^ {\\dagger}\\right) := \\left\\{\\overbrace {\\left[ \\sum_ {i = 1} ^ {n} \\mathrm {D} _ {\\boldsymbol {\\omega} \\boldsymbol {\\omega}} l \\left(\\boldsymbol {\\omega} ^ {*} , \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i} ^ {*}\\right) \\right]} ^ {\\mathcal {M} _ {0} [ \\mathrm {D} _ {\\boldsymbol {\\omega} \\boldsymbol {\\omega}} ]} - \\right.", + "image_path": "4b9a80dbe9bb7019da76d5ddcc4d2cffe41980d730d7b16b01673f774858741d.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 187, + 517, + 234 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 187, + 517, + 234 + ], + "spans": [ + { + "bbox": [ + 304, + 187, + 517, + 234 + ], + "type": "interline_equation", + "content": "\\overbrace {\\left[ \\sum_ {i = i _ {1} ^ {\\dagger}} ^ {i _ {r} ^ {\\dagger}} \\mathrm {D} _ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i} ^ {*}\\right) \\right] - \\left[ \\mathrm {D} _ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i \\dagger} + \\boldsymbol {\\delta} _ {i \\dagger} ^ {*}\\right) \\right]} ^ {\\text {P a r t o f} \\mathcal {M} _ {r} [ \\mathrm {D} _ {\\omega \\omega} ]} ^ {- 1} \\tag {11}", + "image_path": "1923682ce63867fcbc679a3d0eb9dda265eab10adee271c47a2fe28d05972862.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 237, + 477, + 284 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 237, + 477, + 284 + ], + "spans": [ + { + "bbox": [ + 305, + 237, + 477, + 284 + ], + "type": "interline_equation", + "content": "\\cdot \\overbrace {\\left[ \\sum_ {i = i _ {1} ^ {\\dagger}} ^ {i _ {r} ^ {\\dagger}} \\nabla_ {\\omega} l (\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i} + \\boldsymbol {\\delta} _ {i} ^ {*}) + \\nabla_ {\\omega} l (\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\boldsymbol {\\delta} _ {i ^ {\\dagger}} ^ {*}) \\right]} ^ {\\mathcal {M} _ {r} [ \\nabla_ {\\boldsymbol {\\omega}} ]}.", + "image_path": "82249a5c83c58e8f52cb3577d6c00b7e12c7f5a0d8514e94000c5811f3c40731.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 297, + 293, + 518, + 325 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 293, + 518, + 325 + ], + "spans": [ + { + "bbox": [ + 297, + 293, + 518, + 325 + ], + "type": "text", + "content": "Then, the unlearning model with updated parameters " + }, + { + "bbox": [ + 297, + 293, + 518, + 325 + ], + "type": "inline_equation", + "content": "\\omega_{r + 1}^{u}\\coloneqq \\omega^{*} + \\mathbf{U}_{r}(\\boldsymbol{\\omega}^{*},i_{r + 1}^{\\dagger})" + }, + { + "bbox": [ + 297, + 293, + 518, + 325 + ], + "type": "text", + "content": " satisfies the approximate unlearning criteria for the adversarial training model in eq.(6)." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 297, + 334, + 435, + 346 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 334, + 435, + 346 + ], + "spans": [ + { + "bbox": [ + 297, + 334, + 435, + 346 + ], + "type": "text", + "content": "Proof. Please refer to Appendix B.2." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "spans": [ + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "text", + "content": "Stage I. Pre-Unlearning. According to Corollary 1, it is a natural idea to pre-compute and keep in memory the total Hessian " + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "inline_equation", + "content": "\\left[\\sum_{i=1}^{n} \\mathsf{D}_{\\omega \\omega} l(\\boldsymbol{\\omega}^*, \\mathbf{x}_i + \\boldsymbol{\\delta}_i^*)\\right]" + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "text", + "content": " once the ATM is trained and before responding to unlearning requests, since it does not depend on the new point to be removed. Thus, we initialize a memory set " + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_0" + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "text", + "content": " at " + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "inline_equation", + "content": "r = 0" + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "text", + "content": ", which has three memory parts: " + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_0[\\mathsf{D}_{\\omega \\omega}]" + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "text", + "content": " for " + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "inline_equation", + "content": "\\left[\\sum_{i=1}^{n} \\mathsf{D}_{\\omega \\omega} l(\\boldsymbol{\\omega}^*, \\mathbf{x}_i + \\boldsymbol{\\delta}_i^*)\\right]" + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_0[\\boldsymbol{\\omega}^*]" + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "text", + "content": " for " + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "inline_equation", + "content": "\\boldsymbol{\\omega}^*" + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_0[\\nabla_{\\boldsymbol{\\omega}}]" + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "text", + "content": " for " + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "inline_equation", + "content": "\\nabla_{\\boldsymbol{\\omega}} = \\mathbf{0}" + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "text", + "content": " at " + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "inline_equation", + "content": "r = 0" + }, + { + "bbox": [ + 296, + 358, + 518, + 457 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "spans": [ + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "text", + "content": "Stage II. Unlearning. Upon receiving a new unlearning request to forget the " + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "inline_equation", + "content": "i^{\\dagger}" + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "text", + "content": "-th datapoint at timestamp " + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "inline_equation", + "content": "r + 1" + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "text", + "content": ", Corollary 1 indicates that it suffices to compute the total Hessian and gradient only on " + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "inline_equation", + "content": "i^{\\dagger}" + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "text", + "content": " rather than the entire training set, once the memory is set up and maintained. We evaluate the following three parts in sequence: 1) The gradient on " + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "inline_equation", + "content": "i^{\\dagger} \\colon \\nabla_{\\omega} l(\\boldsymbol{\\omega}^{*}, \\mathbf{x}_{i^{\\dagger}} + \\boldsymbol{\\delta}_{i^{\\dagger}}^{*})" + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "text", + "content": "; 2) The total Hessian on " + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "inline_equation", + "content": "i^{\\dagger} \\colon \\mathrm{D}_{\\omega} \\omega l(\\boldsymbol{\\omega}^{*}, \\mathbf{x}_{i^{\\dagger}} + \\boldsymbol{\\delta}_{i^{\\dagger}}^{*})" + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "text", + "content": "; 3) The unlearning update " + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "inline_equation", + "content": "\\mathcal{U}_r(\\boldsymbol{\\omega}^*, i_{r+1}^{\\dagger})" + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "text", + "content": " in eq.(11) and the updated parameters " + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "inline_equation", + "content": "\\boldsymbol{\\omega}_{r+1}^u" + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "text", + "content": ". In addition, we can also inject Gaussian noise by " + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "inline_equation", + "content": "\\boldsymbol{\\omega}_{r+1}^u + \\mathbf{n}" + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "inline_equation", + "content": "\\mathbf{n} \\sim \\mathcal{N}(0, \\sigma^2 \\mathbf{I})" + }, + { + "bbox": [ + 296, + 459, + 517, + 594 + ], + "type": "text", + "content": " to further smooth the remaining data influence to the discrepancy between eq.(3) and eq.(6)." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 297, + 596, + 517, + 618 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 596, + 517, + 618 + ], + "spans": [ + { + "bbox": [ + 297, + 596, + 517, + 618 + ], + "type": "text", + "content": "Stage III. Post-Unlearning. To support subsequent unlearning requests, we update " + }, + { + "bbox": [ + 297, + 596, + 517, + 618 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_{r + 1}" + }, + { + "bbox": [ + 297, + 596, + 517, + 618 + ], + "type": "text", + "content": " based on Corollary 1:" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 306, + 627, + 517, + 640 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 627, + 517, + 640 + ], + "spans": [ + { + "bbox": [ + 306, + 627, + 517, + 640 + ], + "type": "interline_equation", + "content": "\\mathcal {M} _ {r + 1} \\left[ \\mathrm {D} _ {\\omega \\omega} \\right] = \\mathcal {M} _ {r} \\left[ \\mathrm {D} _ {\\omega \\omega} \\right] - \\mathrm {D} _ {\\omega \\omega} l \\left(\\boldsymbol {\\omega} ^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\boldsymbol {\\delta} _ {i ^ {\\dagger}} ^ {*}\\right); \\tag {12}", + "image_path": "e5d69c01190afb1587d606c64cbde4e66579d63fafb621c46d58b09bea6a4277.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 310, + 641, + 517, + 654 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 641, + 517, + 654 + ], + "spans": [ + { + "bbox": [ + 310, + 641, + 517, + 654 + ], + "type": "interline_equation", + "content": "\\mathcal {M} _ {r + 1} [ \\nabla_ {\\omega} ] = \\mathcal {M} _ {r} [ \\nabla_ {\\omega} ] + \\nabla_ {\\omega} l \\left(\\omega^ {*}, \\mathbf {x} _ {i ^ {\\dagger}} + \\boldsymbol {\\delta} _ {i ^ {\\dagger}} ^ {*}\\right), \\tag {13}", + "image_path": "a311de566ee6f73ae2dfddd03a98299b7f2b2739cb4d44a1b804451e6ae955fd.jpg" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 297, + 663, + 516, + 693 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 663, + 516, + 693 + ], + "spans": [ + { + "bbox": [ + 297, + 663, + 516, + 693 + ], + "type": "text", + "content": "where the former is the online update for " + }, + { + "bbox": [ + 297, + 663, + 516, + 693 + ], + "type": "inline_equation", + "content": "\\left[\\sum_{i=1}^{n} \\mathrm{D}_{\\omega \\omega} l\\left(\\omega^{*}, \\mathbf{x}_{i} + \\boldsymbol{\\delta}_{i}^{*}\\right)\\right] - \\left[\\sum_{i=i_{1}^{\\dagger}}^{i_{1}^{\\dagger} + 1} \\mathrm{D}_{\\omega \\omega} l\\left(\\omega^{*}, \\mathbf{x}_{i} + \\boldsymbol{\\delta}_{i}^{*}\\right)\\right]" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 297, + 693, + 477, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 693, + 477, + 714 + ], + "spans": [ + { + "bbox": [ + 297, + 693, + 477, + 714 + ], + "type": "text", + "content": "and the latter is for " + }, + { + "bbox": [ + 297, + 693, + 477, + 714 + ], + "type": "inline_equation", + "content": "\\left[\\sum_{i = i_1}^{i_{r + 1}}\\nabla_{\\omega}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_i + \\boldsymbol{\\delta}_i^*)\\right]" + }, + { + "bbox": [ + 297, + 693, + 477, + 714 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 22 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "spans": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "text", + "content": "4896" + } + ] + } + ], + "index": 23 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 74, + 123, + 503, + 229 + ], + "blocks": [ + { + "bbox": [ + 74, + 123, + 503, + 229 + ], + "lines": [ + { + "bbox": [ + 74, + 123, + 503, + 229 + ], + "spans": [ + { + "bbox": [ + 74, + 123, + 503, + 229 + ], + "type": "image", + "image_path": "f7186078cbb0413cac9155c9148967f6acfcd1491e6ca859ea8c76c3eaa3dce0.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 60, + 235, + 518, + 282 + ], + "lines": [ + { + "bbox": [ + 60, + 235, + 518, + 282 + ], + "spans": [ + { + "bbox": [ + 60, + 235, + 518, + 282 + ], + "type": "text", + "content": "Figure 2: The proposed MUt er framework. Stage I: the pre-unlearning stage prepares the initial memory " + }, + { + "bbox": [ + 60, + 235, + 518, + 282 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_0[\\mathbb{D}_{\\omega \\omega}],\\mathcal{M}_0[\\nabla_{\\omega}],\\mathcal{M}_0[\\omega^* ]" + }, + { + "bbox": [ + 60, + 235, + 518, + 282 + ], + "type": "text", + "content": " . Stage II: the unlearning stage computes the total Hessian and gradient on the data to be forgotten and computes the ATM unlearning update by solving a linear system. Stage II: the post-unlearning stage updates " + }, + { + "bbox": [ + 60, + 235, + 518, + 282 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_{r + 1}[\\mathbb{D}_{\\omega \\omega}]" + }, + { + "bbox": [ + 60, + 235, + 518, + 282 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 60, + 235, + 518, + 282 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_{r + 1}[\\nabla_{\\omega}]" + }, + { + "bbox": [ + 60, + 235, + 518, + 282 + ], + "type": "text", + "content": " to be prepared for the next unlearning request." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 60, + 298, + 277, + 311 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 298, + 277, + 311 + ], + "spans": [ + { + "bbox": [ + 60, + 298, + 277, + 311 + ], + "type": "text", + "content": "4.2. Unlearning without Direct Hessian Inversions" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 60, + 316, + 282, + 407 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 316, + 282, + 407 + ], + "spans": [ + { + "bbox": [ + 60, + 316, + 282, + 407 + ], + "type": "text", + "content": "We now present the approximations and conversions to circumvent the most computationally expensive and potentially numerical unstable parts in the three stages, which are three Hessian matrix inversions: (Inv-1) The total Hessian inversion of " + }, + { + "bbox": [ + 60, + 316, + 282, + 407 + ], + "type": "inline_equation", + "content": "\\left[\\mathcal{M}_r[\\mathrm{D}_{\\omega \\omega}] - \\mathrm{D}_{\\omega \\omega}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_{i^\\dagger} + \\boldsymbol{\\delta}_{i^\\dagger}^*)\\right]^{-1}" + }, + { + "bbox": [ + 60, + 316, + 282, + 407 + ], + "type": "text", + "content": "; (Inv-2) The partial Hessian inversion of " + }, + { + "bbox": [ + 60, + 316, + 282, + 407 + ], + "type": "inline_equation", + "content": "\\partial_{\\delta \\delta}^{-1}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_{i^\\dagger} + \\boldsymbol{\\delta}_{i^\\dagger}^*)" + }, + { + "bbox": [ + 60, + 316, + 282, + 407 + ], + "type": "text", + "content": " inside the total Hessian in Stage II; (Inv-3) The same " + }, + { + "bbox": [ + 60, + 316, + 282, + 407 + ], + "type": "inline_equation", + "content": "\\partial_{\\delta \\delta}^{-1}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_{i^\\dagger} + \\boldsymbol{\\delta}_{i^\\dagger}^*)" + }, + { + "bbox": [ + 60, + 316, + 282, + 407 + ], + "type": "text", + "content": " but in Stage I & III." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 60, + 410, + 282, + 488 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 410, + 282, + 488 + ], + "spans": [ + { + "bbox": [ + 60, + 410, + 282, + 488 + ], + "type": "text", + "content": "Avoid Matrix Inversions (Inv-1/2) jointly by Schur Complement Conversion. After expanding the total Hessian as in eq.(4), we can reorganize " + }, + { + "bbox": [ + 60, + 410, + 282, + 488 + ], + "type": "inline_equation", + "content": "\\left[\\mathcal{M}_r[\\mathbb{D}_{\\omega \\omega}] - \\mathbb{D}_{\\omega \\omega}l(\\boldsymbol{\\omega}^*,\\mathbf{x}_{i^\\dagger} + \\delta_{i^\\dagger}^*)\\right]" + }, + { + "bbox": [ + 60, + 410, + 282, + 488 + ], + "type": "text", + "content": " into the following form " + }, + { + "bbox": [ + 60, + 410, + 282, + 488 + ], + "type": "inline_equation", + "content": "\\mathbf{S} = \\left[\\mathcal{M}_r[\\mathbb{D}_{\\omega \\omega}] - \\partial_{\\omega \\omega}l_{i^\\dagger}^*\\right] - \\left[-\\partial_{\\omega \\delta}\\partial_{\\delta \\delta}^{-1}\\partial_{\\delta \\omega}l_{i^\\dagger}^*\\right]" + }, + { + "bbox": [ + 60, + 410, + 282, + 488 + ], + "type": "text", + "content": ", which can be regarded as the Schur complement of the block matrix " + }, + { + "bbox": [ + 60, + 410, + 282, + 488 + ], + "type": "inline_equation", + "content": "\\mathbf{H}" + }, + { + "bbox": [ + 60, + 410, + 282, + 488 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 64, + 495, + 280, + 530 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 64, + 495, + 280, + 530 + ], + "spans": [ + { + "bbox": [ + 64, + 495, + 280, + 530 + ], + "type": "interline_equation", + "content": "\\mathbf {H} = \\left[ \\begin{array}{l l} \\mathbf {H} _ {1 1} & \\mathbf {H} _ {1 2} \\\\ \\mathbf {H} _ {2 1} & \\mathbf {H} _ {2 2} \\end{array} \\right] = \\left[ \\begin{array}{c c} \\mathcal {M} _ {r} [ \\mathrm {D} _ {\\omega \\omega} ] - \\partial_ {\\omega \\omega} l _ {i ^ {\\dagger}} ^ {*} & \\partial_ {\\omega \\delta} l _ {i ^ {\\dagger}} ^ {*} \\\\ \\partial_ {\\delta \\omega} l _ {i ^ {\\dagger}} ^ {*} & - \\partial_ {\\delta \\delta} l _ {i ^ {\\dagger}} ^ {*} \\end{array} \\right]. \\tag {14}", + "image_path": "782487f1b15b0f3327a5aed36c7ac1c13f3a67f8cc6eda52ad9bf5dfcea34ee4.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 60, + 538, + 280, + 583 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 538, + 280, + 583 + ], + "spans": [ + { + "bbox": [ + 60, + 538, + 280, + 583 + ], + "type": "text", + "content": "By Schur complement lemma, we can find the inversion of " + }, + { + "bbox": [ + 60, + 538, + 280, + 583 + ], + "type": "inline_equation", + "content": "\\mathbf{S}" + }, + { + "bbox": [ + 60, + 538, + 280, + 583 + ], + "type": "text", + "content": " to the inversion of " + }, + { + "bbox": [ + 60, + 538, + 280, + 583 + ], + "type": "inline_equation", + "content": "\\mathbf{H}" + }, + { + "bbox": [ + 60, + 538, + 280, + 583 + ], + "type": "text", + "content": ", then the unlearning update is equivalent to solving a linear system, as summarized in the following Theorem." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 60, + 590, + 280, + 612 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 590, + 280, + 612 + ], + "spans": [ + { + "bbox": [ + 60, + 590, + 280, + 612 + ], + "type": "text", + "content": "Theorem 2. The unlearning update " + }, + { + "bbox": [ + 60, + 590, + 280, + 612 + ], + "type": "inline_equation", + "content": "\\mathfrak{U}_r(\\omega^*, i_{r+1}^\\dagger)" + }, + { + "bbox": [ + 60, + 590, + 280, + 612 + ], + "type": "text", + "content": " in eq.(11) can be equivalently computed by solving the linear system:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 63, + 618, + 289, + 641 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 618, + 289, + 641 + ], + "spans": [ + { + "bbox": [ + 63, + 618, + 289, + 641 + ], + "type": "interline_equation", + "content": "\\left[ \\begin{array}{c c} \\mathcal {M} _ {r} [ \\mathrm {D} _ {\\omega \\omega} ] - \\partial_ {\\omega \\omega} l _ {i ^ {\\dagger}} ^ {*} & \\partial_ {\\omega \\mathbf {x}} l _ {i ^ {\\dagger}} ^ {*} \\\\ \\partial_ {\\mathbf {x} \\omega} l _ {i ^ {\\dagger}} ^ {*} & - \\partial_ {\\mathbf {x x}} l _ {i ^ {\\dagger}} ^ {*} \\end{array} \\right] \\left[ \\begin{array}{c} \\Delta \\boldsymbol {\\omega} \\\\ \\Delta \\boldsymbol {\\alpha} \\end{array} \\right] = \\left[ \\begin{array}{c} \\mathcal {M} _ {r} [ \\nabla \\omega ] + \\nabla_ {\\omega} l _ {i ^ {\\dagger}} ^ {*} \\\\ \\mathbf {0} \\end{array} \\right],", + "image_path": "659813db89c0854fe6bdef3dab9a2b269d175e33a14e11c51591c8e88ad525e1.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 61, + 648, + 280, + 671 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 648, + 280, + 671 + ], + "spans": [ + { + "bbox": [ + 61, + 648, + 280, + 671 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 61, + 648, + 280, + 671 + ], + "type": "inline_equation", + "content": "\\Delta \\omega" + }, + { + "bbox": [ + 61, + 648, + 280, + 671 + ], + "type": "text", + "content": " is the unlearning update " + }, + { + "bbox": [ + 61, + 648, + 280, + 671 + ], + "type": "inline_equation", + "content": "\\mathcal{U}_r(\\omega^*, i_{r+1}^\\dagger)" + }, + { + "bbox": [ + 61, + 648, + 280, + 671 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 61, + 648, + 280, + 671 + ], + "type": "inline_equation", + "content": "\\Delta \\alpha" + }, + { + "bbox": [ + 61, + 648, + 280, + 671 + ], + "type": "text", + "content": " is an auxiliary variable that can be discarded." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 60, + 677, + 281, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 677, + 281, + 711 + ], + "spans": [ + { + "bbox": [ + 60, + 677, + 281, + 711 + ], + "type": "text", + "content": "The linear system in Theorem 2 can be solved by conjugate gradient or fixed point methods, which are more efficient than computing the Hessian inversions (Inv-1/2) directly." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 298, + 517, + 346 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 298, + 517, + 346 + ], + "spans": [ + { + "bbox": [ + 296, + 298, + 517, + 346 + ], + "type": "text", + "content": "Avoid Matrix Inversions (Inv-3) by Neumann Series Approximation. We expand " + }, + { + "bbox": [ + 296, + 298, + 517, + 346 + ], + "type": "inline_equation", + "content": "\\partial_{\\delta \\delta}^{-1}l_i^*" + }, + { + "bbox": [ + 296, + 298, + 517, + 346 + ], + "type": "text", + "content": " by Neumann Series: " + }, + { + "bbox": [ + 296, + 298, + 517, + 346 + ], + "type": "inline_equation", + "content": "\\partial_{\\delta \\delta}^{-1}l_i^* = \\lim_{k\\to \\infty}\\sum_{j = 0}^{k}\\left[\\mathbf{I} - \\partial_{\\mathbf{xx}}l_i^*\\right]^j" + }, + { + "bbox": [ + 296, + 298, + 517, + 346 + ], + "type": "text", + "content": ". Then, clipping at order " + }, + { + "bbox": [ + 296, + 298, + 517, + 346 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 296, + 298, + 517, + 346 + ], + "type": "text", + "content": ", we have the following approximation," + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 309, + 352, + 517, + 368 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 352, + 517, + 368 + ], + "spans": [ + { + "bbox": [ + 309, + 352, + 517, + 368 + ], + "type": "interline_equation", + "content": "\\partial_ {\\delta \\delta} ^ {- 1} l _ {i} ^ {*} \\approx \\mathbf {I} + \\left[ \\mathbf {I} - \\partial_ {\\delta \\delta} l _ {i} ^ {*} \\right] + \\dots + \\left[ \\mathbf {I} - \\partial_ {\\delta \\delta} l _ {i} ^ {*} \\right] ^ {k}. \\tag {15}", + "image_path": "3739b3301ccbabf7f164cb336a851fafbe8e4675a062891e6c099b20591c53bc.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 373, + 516, + 397 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 373, + 516, + 397 + ], + "spans": [ + { + "bbox": [ + 296, + 373, + 516, + 397 + ], + "type": "text", + "content": "Each term in memory " + }, + { + "bbox": [ + 296, + 373, + 516, + 397 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_r[\\mathrm{D}_{\\omega \\omega}]" + }, + { + "bbox": [ + 296, + 373, + 516, + 397 + ], + "type": "text", + "content": " used in Stage I & III can be approximated by " + }, + { + "bbox": [ + 296, + 373, + 516, + 397 + ], + "type": "inline_equation", + "content": "\\mathrm{D}_{\\omega \\omega}l_i^* \\approx \\overline{\\mathrm{D}}_{\\omega \\omega}l_i^* :=" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 327, + 403, + 517, + 433 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 403, + 517, + 433 + ], + "spans": [ + { + "bbox": [ + 327, + 403, + 517, + 433 + ], + "type": "interline_equation", + "content": "\\partial_ {\\omega \\omega} l _ {i} ^ {*} - \\partial_ {\\omega \\delta} l _ {i} ^ {*} \\left(\\sum_ {j = 0} ^ {k} \\left[ \\mathbf {I} - \\partial_ {\\delta \\delta} l _ {i} ^ {*} \\right] ^ {j}\\right) \\partial_ {\\delta \\omega} l _ {i} ^ {*}. \\tag {16}", + "image_path": "6008c3dc13f770967aa634f5e662524f5ca586a041b46d59de39147f412d5f50.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 297, + 440, + 371, + 452 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 440, + 371, + 452 + ], + "spans": [ + { + "bbox": [ + 297, + 440, + 371, + 452 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 296, + 458, + 517, + 514 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 458, + 517, + 514 + ], + "spans": [ + { + "bbox": [ + 296, + 458, + 517, + 514 + ], + "type": "text", + "content": "We conduct experimental evaluations on two groups of machine learning models and four common datasets, under two typical experiment settings in the unlearning literature [21-23, 26]. Our source code, experiment details, and more experiment results can be found in Supplement." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 297, + 519, + 396, + 531 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 519, + 396, + 531 + ], + "spans": [ + { + "bbox": [ + 297, + 519, + 396, + 531 + ], + "type": "text", + "content": "5.1. Experiment Setup" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 297, + 536, + 408, + 546 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 536, + 408, + 546 + ], + "spans": [ + { + "bbox": [ + 297, + 536, + 408, + 546 + ], + "type": "text", + "content": "5.1.1 Models and Datasets" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 296, + 555, + 517, + 600 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 555, + 517, + 600 + ], + "spans": [ + { + "bbox": [ + 296, + 555, + 517, + 600 + ], + "type": "text", + "content": "Linear Models. We consider two linear models: 1) Ridge Regression (RR) with least square loss; 2) Logistic Regression (LR) with logistic loss, both are regularized by squared " + }, + { + "bbox": [ + 296, + 555, + 517, + 600 + ], + "type": "inline_equation", + "content": "\\ell_2" + }, + { + "bbox": [ + 296, + 555, + 517, + 600 + ], + "type": "text", + "content": "-norm with hyperparameter " + }, + { + "bbox": [ + 296, + 555, + 517, + 600 + ], + "type": "inline_equation", + "content": "\\lambda = 1e - 4" + }, + { + "bbox": [ + 296, + 555, + 517, + 600 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 296, + 601, + 517, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 601, + 517, + 711 + ], + "spans": [ + { + "bbox": [ + 296, + 601, + 517, + 711 + ], + "type": "text", + "content": "Neural Network Models. We utilize the Wide ResNet model (i.e., Wide ResNet 28-10 model) [63] and consider the pretraining setting [22, 26] (also similar to the mixed-privacy removal setting [21]) for the neural network model as follows. We first pretrain a model on a core dataset with adversarial training. We then finetune the model on another target dataset with adversarial finetuning [28], where all layers are frozen except the last layer. We consider unlearning requests from only the target dataset used for the adversarial finetuning." + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 737, + 298, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 737, + 298, + 746 + ], + "spans": [ + { + "bbox": [ + 279, + 737, + 298, + 746 + ], + "type": "text", + "content": "4897" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "bbox": [ + 60, + 125, + 282, + 202 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 125, + 282, + 202 + ], + "spans": [ + { + "bbox": [ + 60, + 125, + 282, + 202 + ], + "type": "text", + "content": "Adversarial Training/Finetuning Algorithms. For outer-level, we utilize SGD to optimize the model parameters " + }, + { + "bbox": [ + 60, + 125, + 282, + 202 + ], + "type": "inline_equation", + "content": "\\omega^{*}" + }, + { + "bbox": [ + 60, + 125, + 282, + 202 + ], + "type": "text", + "content": "; for inner-level, we utilize both PGD [39] and FGSM [24] to generate adversarial perturbations. The experiment results by PGD are reported in the paper, while the results by FGSM and more detailed training and finetuning settings are relegated to Appendix A.1 and A.3." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 60, + 205, + 282, + 304 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 205, + 282, + 304 + ], + "spans": [ + { + "bbox": [ + 60, + 205, + 282, + 304 + ], + "type": "text", + "content": "Datasets. We consider four common datasets for the two settings above: (linear models) i) MNIST-" + }, + { + "bbox": [ + 60, + 205, + 282, + 304 + ], + "type": "inline_equation", + "content": "\\mathbf{b}" + }, + { + "bbox": [ + 60, + 205, + 282, + 304 + ], + "type": "text", + "content": " is the subset from MNIST with classes '1' and '7' for binary classification purpose; ii) Covtype is a dataset from the LIBSVM repository [10]; (neural network model with pretraining) iii) CIFAR-10 (target dataset) and the Downsampled ImageNet (core dataset) are both natural image datasets; iv) Lacuna-10 (target dataset) and Lacuna-100 (core dataset) are both face datasets. More detail can be found in Appendix A.2." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 61, + 318, + 206, + 330 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 318, + 206, + 330 + ], + "spans": [ + { + "bbox": [ + 61, + 318, + 206, + 330 + ], + "type": "text", + "content": "5.1.2 Baseline Unlearning Methods" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 60, + 335, + 282, + 547 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 335, + 282, + 547 + ], + "spans": [ + { + "bbox": [ + 60, + 335, + 282, + 547 + ], + "type": "text", + "content": "We compare MUt er with six approximate unlearning methods (with their abbreviations in bold), all of which are originally designed for unlearning from standard training models. Since they utilize different Hessian terms in the unlearning update, for a fair comparison, we evaluate them under the same three-stage framework as MUt er but substitute in their corresponding unlearning update formulations. (1) Newton unlearning [26] and (2) Newton unlearning measured with adversarial perturbation (Newton-delta): both methods utilize the Newton step as the unlearning update, where the former computes at the original samples (i.e., " + }, + { + "bbox": [ + 60, + 335, + 282, + 547 + ], + "type": "inline_equation", + "content": "\\left[\\sum_{i = 1,i\\neq i\\dagger}^{n}\\partial_{\\omega \\omega}l(\\boldsymbol{\\omega}^{*},\\mathbf{x}_{i})\\right]^{-1}\\nabla_{\\omega}l(\\boldsymbol{\\omega}^{*},\\mathbf{x}_{i\\dagger})" + }, + { + "bbox": [ + 60, + 335, + 282, + 547 + ], + "type": "text", + "content": " and the latter at the adversarially perturbed samples (i.e., " + }, + { + "bbox": [ + 60, + 335, + 282, + 547 + ], + "type": "inline_equation", + "content": "\\left[\\sum_{i = 1,i\\neq i\\dagger}^{n}\\partial_{\\omega \\omega}l(\\boldsymbol{\\omega}^{*},\\mathbf{x}_{i} + \\boldsymbol{\\delta}_{i}^{*})\\right]^{-1}\\nabla_{\\omega}l(\\boldsymbol{\\omega}^{*},\\mathbf{x}_{i\\dagger} + \\boldsymbol{\\delta}_{i\\dagger}^{*})" + }, + { + "bbox": [ + 60, + 335, + 282, + 547 + ], + "type": "text", + "content": "). Similarly, we have (3) Fisher unlearning [22] and (4) Fisher-delta, which utilize the Fisher matrix " + }, + { + "bbox": [ + 60, + 335, + 282, + 547 + ], + "type": "inline_equation", + "content": "(\\nabla_{\\omega}l\\cdot \\nabla_{\\omega}^{\\top}l)" + }, + { + "bbox": [ + 60, + 335, + 282, + 547 + ], + "type": "text", + "content": " to approximate the direct Hessian " + }, + { + "bbox": [ + 60, + 335, + 282, + 547 + ], + "type": "inline_equation", + "content": "\\partial_{\\omega \\omega}l" + }, + { + "bbox": [ + 60, + 335, + 282, + 547 + ], + "type": "text", + "content": ". (5) Influence function-based unlearning [32, 40] and (6) Influence-delta, which utilize the influence function for STM for the unlearning update." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 60, + 547, + 282, + 592 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 547, + 282, + 592 + ], + "spans": [ + { + "bbox": [ + 60, + 547, + 282, + 592 + ], + "type": "text", + "content": "Meanwhile, we utilize (7) Retrain-from-scratch as the golden standard reference, which applies the same adversarial training/finetuning algorithms to retrain/re-finetune the model on the remaining data to obtain " + }, + { + "bbox": [ + 60, + 547, + 282, + 592 + ], + "type": "inline_equation", + "content": "\\omega_{-i\\dagger}^{*}" + }, + { + "bbox": [ + 60, + 547, + 282, + 592 + ], + "type": "text", + "content": " in eq.(3)." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 61, + 605, + 167, + 616 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 605, + 167, + 616 + ], + "spans": [ + { + "bbox": [ + 61, + 605, + 167, + 616 + ], + "type": "text", + "content": "5.1.3 Evaluation Metrics" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 60, + 623, + 282, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 623, + 282, + 711 + ], + "spans": [ + { + "bbox": [ + 60, + 623, + 282, + 711 + ], + "type": "text", + "content": "We measure four aspects of the unlearning performance: 1) Effectiveness measures the closeness of the unlearned ATM compared to the golden standard Retrain, for which we utilize the " + }, + { + "bbox": [ + 60, + 623, + 282, + 711 + ], + "type": "inline_equation", + "content": "\\ell_2" + }, + { + "bbox": [ + 60, + 623, + 282, + 711 + ], + "type": "text", + "content": "-norm difference between the model parameter vectors, i.e., " + }, + { + "bbox": [ + 60, + 623, + 282, + 711 + ], + "type": "inline_equation", + "content": "\\| \\boldsymbol{\\omega}^u - \\boldsymbol{\\omega}_{-i^\\dagger}^*\\|_2" + }, + { + "bbox": [ + 60, + 623, + 282, + 711 + ], + "type": "text", + "content": "; 2) Accuracy measures the clean accuracy of the unlearned ATM, for which we utilize the accuracy on clean test samples; 3) Robustness measures the adversarial accuracy of the unlearned ATM, for which we" + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 324, + 125, + 504, + 140 + ], + "blocks": [ + { + "bbox": [ + 324, + 125, + 504, + 140 + ], + "lines": [ + { + "bbox": [ + 324, + 125, + 504, + 140 + ], + "spans": [ + { + "bbox": [ + 324, + 125, + 504, + 140 + ], + "type": "image", + "image_path": "4afe7bbf0ba6b56c8523ef5d19617b8520776a4229d1c6cd31795b8e4ec439e9.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 307, + 147, + 405, + 241 + ], + "blocks": [ + { + "bbox": [ + 307, + 147, + 405, + 241 + ], + "lines": [ + { + "bbox": [ + 307, + 147, + 405, + 241 + ], + "spans": [ + { + "bbox": [ + 307, + 147, + 405, + 241 + ], + "type": "image", + "image_path": "35c6e74f40f345acdceba95852e24680e1b867577f3afac37d3a4878759a95b2.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 409, + 146, + 509, + 241 + ], + "blocks": [ + { + "bbox": [ + 409, + 146, + 509, + 241 + ], + "lines": [ + { + "bbox": [ + 409, + 146, + 509, + 241 + ], + "spans": [ + { + "bbox": [ + 409, + 146, + 509, + 241 + ], + "type": "image", + "image_path": "9bc1066fe0a1f511b909a0cb64ffccef84ff021afe13f0e67968316982485dfb.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 308, + 255, + 407, + 344 + ], + "blocks": [ + { + "bbox": [ + 308, + 255, + 407, + 344 + ], + "lines": [ + { + "bbox": [ + 308, + 255, + 407, + 344 + ], + "spans": [ + { + "bbox": [ + 308, + 255, + 407, + 344 + ], + "type": "image", + "image_path": "4382d88274c5ed09a758410e7ce0f5f61cb6ece613f9531cf56ca4f735fc644c.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 409, + 255, + 509, + 344 + ], + "blocks": [ + { + "bbox": [ + 409, + 255, + 509, + 344 + ], + "lines": [ + { + "bbox": [ + 409, + 255, + 509, + 344 + ], + "spans": [ + { + "bbox": [ + 409, + 255, + 509, + 344 + ], + "type": "image", + "image_path": "12d3b37e9d690e749d929c53e69791414955c90c0b539ae2d60891327bca19ec.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 307, + 356, + 404, + 447 + ], + "blocks": [ + { + "bbox": [ + 307, + 356, + 404, + 447 + ], + "lines": [ + { + "bbox": [ + 307, + 356, + 404, + 447 + ], + "spans": [ + { + "bbox": [ + 307, + 356, + 404, + 447 + ], + "type": "image", + "image_path": "80a7067843a62b970e9103df3197b39178d2750d33b0d1c3edfe511a450c19ca.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "lines": [ + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "spans": [ + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "type": "text", + "content": "Figure 3: Evaluation results on Logistic Regression Model: Effectiveness (top), Accuracy (middle), and Robustness (bottom) on datasets MNIST-b (left column), Covtype (right column). Large plots have greater removal numbers: " + }, + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "type": "inline_equation", + "content": "1\\%" + }, + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "type": "inline_equation", + "content": "2\\%" + }, + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "type": "inline_equation", + "content": "\\cdots" + }, + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "type": "inline_equation", + "content": "5\\%" + }, + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "type": "text", + "content": "; the inside small plots have fewer removal numbers: " + }, + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "type": "inline_equation", + "content": "1,2,\\cdots,5" + }, + { + "bbox": [ + 296, + 464, + 518, + 531 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 408, + 357, + 509, + 447 + ], + "blocks": [ + { + "bbox": [ + 408, + 357, + 509, + 447 + ], + "lines": [ + { + "bbox": [ + 408, + 357, + 509, + 447 + ], + "spans": [ + { + "bbox": [ + 408, + 357, + 509, + 447 + ], + "type": "image", + "image_path": "754bc211380f4d6c78d872df2248456c4ccb19ef2630c0da505970a3cd0b55b1.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + } + ], + "index": 13 + }, + { + "bbox": [ + 296, + 551, + 518, + 596 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 551, + 518, + 596 + ], + "spans": [ + { + "bbox": [ + 296, + 551, + 518, + 596 + ], + "type": "text", + "content": "utilize the accuracy on adversarial perturbed test samples; 4) Efficiency measures the unlearning time the unlearning method takes to respond the unlearning request, for which we report CPU time." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 297, + 604, + 403, + 616 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 604, + 403, + 616 + ], + "spans": [ + { + "bbox": [ + 297, + 604, + 403, + 616 + ], + "type": "text", + "content": "5.2. Experiment Results" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 297, + 622, + 431, + 633 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 622, + 431, + 633 + ], + "spans": [ + { + "bbox": [ + 297, + 622, + 431, + 633 + ], + "type": "text", + "content": "5.2.1 Results with Linear Model" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 296, + 641, + 518, + 674 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 641, + 518, + 674 + ], + "spans": [ + { + "bbox": [ + 296, + 641, + 518, + 674 + ], + "type": "text", + "content": "Figure 3 reports the experiment results with logistic regression model on the MNIST-b and Covtypes datasets. More results with ridge regression are deferred to Appendix A.3." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 296, + 677, + 518, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 677, + 518, + 712 + ], + "spans": [ + { + "bbox": [ + 296, + 677, + 518, + 712 + ], + "type": "text", + "content": "Effectiveness. Top row of Figure 3 shows the effectiveness comparison. All compared methods have increased model parameter distance with the increasing number of unlearning" + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "spans": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "text", + "content": "4898" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 70, + 127, + 173, + 226 + ], + "blocks": [ + { + "bbox": [ + 70, + 127, + 173, + 226 + ], + "lines": [ + { + "bbox": [ + 70, + 127, + 173, + 226 + ], + "spans": [ + { + "bbox": [ + 70, + 127, + 173, + 226 + ], + "type": "image", + "image_path": "a73fdcc799b61851c5bf67004c89ee7faba69f0430875a5920da4cfaf0419553.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 176, + 128, + 274, + 227 + ], + "blocks": [ + { + "bbox": [ + 176, + 128, + 274, + 227 + ], + "lines": [ + { + "bbox": [ + 176, + 128, + 274, + 227 + ], + "spans": [ + { + "bbox": [ + 176, + 128, + 274, + 227 + ], + "type": "image", + "image_path": "83ba5f1b25738a31a57e20f15cad1bb753270bfdbe402b6182adca821842378a.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 67, + 228, + 173, + 325 + ], + "blocks": [ + { + "bbox": [ + 67, + 228, + 173, + 325 + ], + "lines": [ + { + "bbox": [ + 67, + 228, + 173, + 325 + ], + "spans": [ + { + "bbox": [ + 67, + 228, + 173, + 325 + ], + "type": "image", + "image_path": "5e5d26435969fe46870b32b04bbe8957efb787ab6ad4d45938350c6dadca044e.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 173, + 229, + 274, + 325 + ], + "blocks": [ + { + "bbox": [ + 173, + 229, + 274, + 325 + ], + "lines": [ + { + "bbox": [ + 173, + 229, + 274, + 325 + ], + "spans": [ + { + "bbox": [ + 173, + 229, + 274, + 325 + ], + "type": "image", + "image_path": "a81c2e680793d79c43a011598a0e0b37139e7d3bf307a330a0770ea4eb30f4ec.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 66, + 326, + 172, + 423 + ], + "blocks": [ + { + "bbox": [ + 66, + 326, + 172, + 423 + ], + "lines": [ + { + "bbox": [ + 66, + 326, + 172, + 423 + ], + "spans": [ + { + "bbox": [ + 66, + 326, + 172, + 423 + ], + "type": "image", + "image_path": "3f87baacd32401b9f056d0598dcde1102b78044f81e0add1831d7aaa73887589.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 60, + 436, + 282, + 481 + ], + "lines": [ + { + "bbox": [ + 60, + 436, + 282, + 481 + ], + "spans": [ + { + "bbox": [ + 60, + 436, + 282, + 481 + ], + "type": "text", + "content": "Figure 4: Evaluation results on Neural Network: Effectiveness (top), Accuracy (middle), and Robustness (bottom) on datasets Lacuna-10 (left column) and CIFAR-10 (right column), under removal numbers " + }, + { + "bbox": [ + 60, + 436, + 282, + 481 + ], + "type": "inline_equation", + "content": "(1,0.4\\%, 1\\%, 2\\%, 4\\%, 8\\%)" + }, + { + "bbox": [ + 60, + 436, + 282, + 481 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 172, + 331, + 274, + 423 + ], + "blocks": [ + { + "bbox": [ + 172, + 331, + 274, + 423 + ], + "lines": [ + { + "bbox": [ + 172, + 331, + 274, + 423 + ], + "spans": [ + { + "bbox": [ + 172, + 331, + 274, + 423 + ], + "type": "image", + "image_path": "15861c24a1c405179ae16bb1a768abcbe8bbf5c9f3cdc673914115f8d39da6e3.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 64, + 492, + 280, + 558 + ], + "blocks": [ + { + "bbox": [ + 64, + 492, + 280, + 558 + ], + "lines": [ + { + "bbox": [ + 64, + 492, + 280, + 558 + ], + "spans": [ + { + "bbox": [ + 64, + 492, + 280, + 558 + ], + "type": "table", + "html": "
Model TypeRemoval NumberMNIST-bCovtype
FisherF-deltaMIterRetrainFisherF-deltaMIterRetrain
LR10.0020.0020.009630.0020.0020.007192
50.0100.0120.052630.0090.0110.037194
100.0190.0210.106620.0180.0220.071194
RR10.0020.0020.009640.0020.0020.006200
50.0090.0110.057650.0110.0120.032206
100.0180.0190.097650.0190.0200.064205
", + "image_path": "dd78cf12c80061f42aaae032e89511cb4cdd35d05c5c4af68f0cf7dc4cce7501.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 60, + 629, + 280, + 685 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 629, + 280, + 685 + ], + "spans": [ + { + "bbox": [ + 60, + 629, + 280, + 685 + ], + "type": "text", + "content": "requests, which is due to the decreased approximation capability of the approximate unlearning criteria. MUter achieves the smallest deviation from Retrain and outperforms all the compared methods, which is because its ATM unlearning update sufficiently captures the nested data influence in ATM." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 60, + 688, + 281, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 688, + 281, + 711 + ], + "spans": [ + { + "bbox": [ + 60, + 688, + 281, + 711 + ], + "type": "text", + "content": "Accuracy. Middle row of Figure 3 shows the clean accuracy comparison. All unlearning methods do not show a signifi" + } + ] + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 301, + 123, + 517, + 170 + ], + "blocks": [ + { + "bbox": [ + 60, + 564, + 280, + 609 + ], + "lines": [ + { + "bbox": [ + 60, + 564, + 280, + 609 + ], + "spans": [ + { + "bbox": [ + 60, + 564, + 280, + 609 + ], + "type": "text", + "content": "Table 1: Efficiency results with linear models of logistic regression (top) and ridge regression (bottom): The unlearning time (in seconds) of Fisher, Fisher-delta, MUt er and Retrain under varying removal numbers: 1, 5, 10." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 301, + 123, + 517, + 170 + ], + "lines": [ + { + "bbox": [ + 301, + 123, + 517, + 170 + ], + "spans": [ + { + "bbox": [ + 301, + 123, + 517, + 170 + ], + "type": "table", + "html": "
Removal NumberLacuna-10CIFAR-10
FisherF-deltaMUtErRetrainFisherF-deltaMUtErRetrain
11.471.664.189351.511.733.815224
57.768.4121.379347.548.5818.645294
1015.5116.8241.6993215.3416.4237.575260
", + "image_path": "a19eab8f374592a356b973b1eb9038e032ad9017eb8241fa367335ab712ea8ce.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 296, + 178, + 518, + 211 + ], + "lines": [ + { + "bbox": [ + 296, + 178, + 518, + 211 + ], + "spans": [ + { + "bbox": [ + 296, + 178, + 518, + 211 + ], + "type": "text", + "content": "Table 2: Efficiency results with Neural Network: The unlearning time (in seconds) of Fisher, Fisher-delta, MUt er and Retrain under varying removal numbers: 1, 5, 10." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 296, + 231, + 517, + 264 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 231, + 517, + 264 + ], + "spans": [ + { + "bbox": [ + 296, + 231, + 517, + 264 + ], + "type": "text", + "content": "cant drop in clean accuracy after data forgotten. In general, " + }, + { + "bbox": [ + 296, + 231, + 517, + 264 + ], + "type": "inline_equation", + "content": "MUtEr" + }, + { + "bbox": [ + 296, + 231, + 517, + 264 + ], + "type": "text", + "content": " is among the methods that achieve higher accuracy and exhibits close consistency with Retrain." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 296, + 266, + 517, + 344 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 266, + 517, + 344 + ], + "spans": [ + { + "bbox": [ + 296, + 266, + 517, + 344 + ], + "type": "text", + "content": "Robustness. Bottom row of Figure 3 shows the robustness comparison. When the number of forgotten requests is small, most methods have little variation in perturbed accuracy. When the forgotten number becomes larger, all baseline unlearning methods have an obvious decrease in perturbed accuracy, while MUt er still shows high perturbed accuracy and has the closest proximity to Retrain." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 296, + 346, + 517, + 479 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 346, + 517, + 479 + ], + "spans": [ + { + "bbox": [ + 296, + 346, + 517, + 479 + ], + "type": "text", + "content": "Efficiency. Table 1 shows the efficiency comparison. MUt er has significant efficiency improvement over Retrain, which is the utmost desideratum of the unlearning method. In addition, we compare with Fisher and Fisher-delta, which are the most efficient methods among the six baseline methods due to the more efficient Fisher information matrix approximation. MUt er takes more CPU time because it computes the total Hessian to obtain a more holistic data influence measure, while the baseline methods compute only the (approximate) direct Hessian and omit the indirect Hessian. Thus, the small increase in CPU time is the necessary tax to pay in exchange for more effective unlearning." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 296, + 481, + 517, + 569 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 481, + 517, + 569 + ], + "spans": [ + { + "bbox": [ + 296, + 481, + 517, + 569 + ], + "type": "text", + "content": "Tradeoff between deletion effectiveness, accuracy, and robustness. According to the above results, there is a tradeoff between efficient and deletion effectiveness, accuracy, and robustness. That is, " + }, + { + "bbox": [ + 296, + 481, + 517, + 569 + ], + "type": "inline_equation", + "content": "MUtEr" + }, + { + "bbox": [ + 296, + 481, + 517, + 569 + ], + "type": "text", + "content": " takes slightly longer than direct Hessian-only unlearning methods due to the additional computation of the indirect Hessian. However, this extra computation is worthwhile as " + }, + { + "bbox": [ + 296, + 481, + 517, + 569 + ], + "type": "inline_equation", + "content": "MUtEr" + }, + { + "bbox": [ + 296, + 481, + 517, + 569 + ], + "type": "text", + "content": " offers improved deletion effectiveness, accuracy, and robustness." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 297, + 584, + 468, + 594 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 584, + 468, + 594 + ], + "spans": [ + { + "bbox": [ + 297, + 584, + 468, + 594 + ], + "type": "text", + "content": "5.2.2 Results with Neural Network Model" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 296, + 602, + 517, + 710 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 602, + 517, + 710 + ], + "spans": [ + { + "bbox": [ + 296, + 602, + 517, + 710 + ], + "type": "text", + "content": "Figure 4 summarizes the results of effectiveness, accuracy, and robustness on the two datasets for the neural network model with pretraining. MUt er has the smallest difference of parameter distance with Retrain, which indicates that MUt er generates the most similar unlearning model to the Retrain model. In addition, MUt er has the most consistent behaviour with Retrain in terms of clean accuracy and perturbation accuracy. In terms of efficiency, Table 2 reports the comparison with Retrain and two most efficient baseline methods Fisher and Fisher-delta. Similar to the linear" + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "spans": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "text", + "content": "4899" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 123, + 126, + 229, + 215 + ], + "blocks": [ + { + "bbox": [ + 123, + 126, + 229, + 215 + ], + "lines": [ + { + "bbox": [ + 123, + 126, + 229, + 215 + ], + "spans": [ + { + "bbox": [ + 123, + 126, + 229, + 215 + ], + "type": "image", + "image_path": "25a2f5f6f29b3319475d2a42d728ad31266fce976a66d471de7e54bb1a024fe5.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 60, + 227, + 518, + 250 + ], + "lines": [ + { + "bbox": [ + 60, + 227, + 518, + 250 + ], + "spans": [ + { + "bbox": [ + 60, + 227, + 518, + 250 + ], + "type": "text", + "content": "Figure 5: Effect of Gaussian noise injection: Effectiveness (left), Accuracy (middle), and Robustness (right) versus the standard variation " + }, + { + "bbox": [ + 60, + 227, + 518, + 250 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 60, + 227, + 518, + 250 + ], + "type": "text", + "content": " of Gaussian noise in log scale, under the case of removing " + }, + { + "bbox": [ + 60, + 227, + 518, + 250 + ], + "type": "inline_equation", + "content": "5\\%" + }, + { + "bbox": [ + 60, + 227, + 518, + 250 + ], + "type": "text", + "content": " samples and on the Lacuna-10 dataset." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 236, + 127, + 342, + 215 + ], + "blocks": [ + { + "bbox": [ + 236, + 127, + 342, + 215 + ], + "lines": [ + { + "bbox": [ + 236, + 127, + 342, + 215 + ], + "spans": [ + { + "bbox": [ + 236, + 127, + 342, + 215 + ], + "type": "image", + "image_path": "77d03821b289f247a743d56bf2ade4c7706f59c4674980356d35b3c5414a8ae3.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 349, + 127, + 456, + 215 + ], + "blocks": [ + { + "bbox": [ + 349, + 127, + 456, + 215 + ], + "lines": [ + { + "bbox": [ + 349, + 127, + 456, + 215 + ], + "spans": [ + { + "bbox": [ + 349, + 127, + 456, + 215 + ], + "type": "image", + "image_path": "ae00c2840e6e62d9da79df0ee15f1fb7eba876aecf2c9775abe499e6d22dd95c.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 60, + 268, + 280, + 313 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 268, + 280, + 313 + ], + "spans": [ + { + "bbox": [ + 60, + 268, + 280, + 313 + ], + "type": "text", + "content": "model case, MUt er has significant efficiency improvement over Retrain. Although MUt er costs more unlearning time than the approximate methods, it provides significantly more effective, more accurate, and more robust unlearned ATM." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "spans": [ + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "type": "text", + "content": "Effect of Varying Magnitudes of Gaussian Noise. Figure 5 shows the effectiveness, accuracy, and robustness comparisons under varying standard variations of Gaussian noise " + }, + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "type": "inline_equation", + "content": "(\\sigma)" + }, + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "type": "text", + "content": " injected by " + }, + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "type": "inline_equation", + "content": "\\omega_{r + 1}^u +\\mathbf{n}" + }, + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "type": "inline_equation", + "content": "\\mathbf{n}\\sim \\mathcal{N}(0,\\sigma^2\\mathbf{I})" + }, + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "type": "text", + "content": ". All methods get worse unlearning model performance with larger " + }, + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "type": "text", + "content": ", but MUt er maintains the best performance for all " + }, + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 60, + 315, + 282, + 392 + ], + "type": "text", + "content": "’s among all compared unlearning methods." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 61, + 402, + 128, + 414 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 402, + 128, + 414 + ], + "spans": [ + { + "bbox": [ + 61, + 402, + 128, + 414 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 60, + 420, + 282, + 551 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 420, + 282, + 551 + ], + "spans": [ + { + "bbox": [ + 60, + 420, + 282, + 551 + ], + "type": "text", + "content": "In this paper, we studied a new joint privacy-robustness problem of machine unlearning from adversarial training models to simultaneously meet the emerging privacy regulations on Right to be Forgotten and ensure the adversarial robustness of the model. We proposed a new unlearning method called Muter, which is underpinned by a total Hessian-based measure to sufficiently capture the data influence on both model parameters and adversarial perturbations. We further introduced the Schur complement conversion and the Neumann series approximation to mitigate the computational cost. Our methods show significant enhancement in effectiveness and efficiency compared to baseline methods." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 60, + 551, + 280, + 661 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 551, + 280, + 661 + ], + "spans": [ + { + "bbox": [ + 60, + 551, + 280, + 661 + ], + "type": "text", + "content": "As future works, several directions can be further explored: 1) extending " + }, + { + "bbox": [ + 60, + 551, + 280, + 661 + ], + "type": "inline_equation", + "content": "MUter" + }, + { + "bbox": [ + 60, + 551, + 280, + 661 + ], + "type": "text", + "content": " to other adversarial training variants like adversarial regularization; 2) further reducing the memory cost by considering low-rank/k-fact approximations to approximate the Hessian matrix, e.g., [25]; 3) studying the approximation capability of the new influence function inspired by " + }, + { + "bbox": [ + 60, + 551, + 280, + 661 + ], + "type": "inline_equation", + "content": "MUter" + }, + { + "bbox": [ + 60, + 551, + 280, + 661 + ], + "type": "text", + "content": ", e.g., across different depths of neural networks [4]; 4) exploring the potential connection between the new influence function with proximal Bregman response function [2]." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 61, + 671, + 162, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 671, + 162, + 682 + ], + "spans": [ + { + "bbox": [ + 61, + 671, + 162, + 682 + ], + "type": "text", + "content": "7. Acknowledgement" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 60, + 688, + 280, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 688, + 280, + 711 + ], + "spans": [ + { + "bbox": [ + 60, + 688, + 280, + 711 + ], + "type": "text", + "content": "The authors would like to thank the anonymous reviewers for their constructive comments. This research has been" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 268, + 518, + 335 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 268, + 518, + 335 + ], + "spans": [ + { + "bbox": [ + 296, + 268, + 518, + 335 + ], + "type": "text", + "content": "funded in part by National Science Foundation of China (NSFC) 62206207, 62102300, 62072395, and U20A20178, National Key Research and Development Program of China 2020AAA0107705, National Science Foundation (NSF) CNS-2124104, CNS-2125530, and National Institute of Health (NIH) R01ES033241." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 298, + 350, + 351, + 362 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 350, + 351, + 362 + ], + "spans": [ + { + "bbox": [ + 298, + 350, + 351, + 362 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 302, + 370, + 518, + 711 + ], + "type": "list", + "angle": 0, + "index": 21, + "blocks": [ + { + "bbox": [ + 302, + 370, + 518, + 420 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 302, + 370, + 518, + 420 + ], + "spans": [ + { + "bbox": [ + 302, + 370, + 518, + 420 + ], + "type": "text", + "content": "[1] Martin Abadi, Andy Chu, Ian Goodfellow, H Brendan McMahan, Ilya Mironov, Kunal Talwar, and Li Zhang. Deep learning with differential privacy. In Proceedings of the 2016 ACM SIGSAC conference on computer and communications security, 2016. 1" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 302, + 423, + 517, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 302, + 423, + 517, + 453 + ], + "spans": [ + { + "bbox": [ + 302, + 423, + 517, + 453 + ], + "type": "text", + "content": "[2] Juhan Bae, Nathan Ng, Alston Lo, Marzyeh Ghassemi, and Roger B. Grosse. If influence functions are the answer, then what is the question? In NeurIPS, 2022. 9" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 302, + 456, + 518, + 506 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 302, + 456, + 518, + 506 + ], + "spans": [ + { + "bbox": [ + 302, + 456, + 518, + 506 + ], + "type": "text", + "content": "[3] Tao Bai, Jinqi Luo, Jun Zhao, Bihan Wen, and Qian Wang. Recent advances in adversarial training for adversarial robustness. In Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence, pages 4312-4321, 8 2021. Survey Track. 1" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 302, + 509, + 518, + 549 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 302, + 509, + 518, + 549 + ], + "spans": [ + { + "bbox": [ + 302, + 509, + 518, + 549 + ], + "type": "text", + "content": "[4] Samyadeep Basu, Phillip Pope, and Soheil Feizi. Influence functions in deep learning are fragile. In 9th International Conference on Learning Representations, ICLR 2021, Virtual Event, Austria, May 3-7, 2021, 2021. 9" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 302, + 552, + 518, + 592 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 302, + 552, + 518, + 592 + ], + "spans": [ + { + "bbox": [ + 302, + 552, + 518, + 592 + ], + "type": "text", + "content": "[5] Lucas Bourtoule, Varun Chandrasekaran, Christopher A. Choquette-Choo, Hengrui Jia, Adelin Travers, Baiwu Zhang, David Lie, and Nicolas Papernot. Machine unlearning. In 42nd IEEE Symposium on Security and Privacy, 2021. 1, 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 302, + 595, + 518, + 625 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 302, + 595, + 518, + 625 + ], + "spans": [ + { + "bbox": [ + 302, + 595, + 518, + 625 + ], + "type": "text", + "content": "[6] Jonathan Brophy and Daniel Lowd. Machine unlearning for random forests. In International Conference on Machine Learning, pages 1092-1104, 2021. 3" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 302, + 628, + 518, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 302, + 628, + 518, + 678 + ], + "spans": [ + { + "bbox": [ + 302, + 628, + 518, + 678 + ], + "type": "text", + "content": "[7] Qiong Cao, Li Shen, Weidi Xie, Omkar M. Parkhi, and Andrew Zisserman. Vggface2: A dataset for recognising faces across pose and age. In 2018 13th IEEE International Conference on Automatic Face Gesture Recognition (FG 2018), pages 67-74, 2018. 12" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 302, + 680, + 518, + 711 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 302, + 680, + 518, + 711 + ], + "spans": [ + { + "bbox": [ + 302, + 680, + 518, + 711 + ], + "type": "text", + "content": "[8] Yinzhi Cao and Junfeng Yang. Towards making systems forget with machine unlearning. In 2015 IEEE Symposium on Security and Privacy, pages 463-480. IEEE, 2015. 1, 3" + } + ] + } + ], + "index": 20 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "spans": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "text", + "content": "4900" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 62, + 126, + 280, + 710 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 66, + 126, + 280, + 156 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 126, + 280, + 156 + ], + "spans": [ + { + "bbox": [ + 66, + 126, + 280, + 156 + ], + "type": "text", + "content": "[9] Nicholas Carlini and David Wagner. Towards evaluating the robustness of neural networks. In 2017 IEEE Symposium on Security and Privacy. IEEE Computer Society, 2017. 1" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 63, + 157, + 280, + 186 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 157, + 280, + 186 + ], + "spans": [ + { + "bbox": [ + 63, + 157, + 280, + 186 + ], + "type": "text", + "content": "[10] Chih-Chung Chang and Chih-Jen Lin. Libsvm: A library for support vector machines. ACM Trans. Intell. Syst. Technol., 2(3), may 2011. 7" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 62, + 188, + 280, + 218 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 188, + 280, + 218 + ], + "spans": [ + { + "bbox": [ + 62, + 188, + 280, + 218 + ], + "type": "text", + "content": "[11] Chong Chen, Fei Sun, Min Zhang, and Bolin Ding. Recommendation unlearning. In Proceedings of the ACM Web Conference 2022, pages 2768-2777, 2022. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 63, + 219, + 280, + 258 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 219, + 280, + 258 + ], + "spans": [ + { + "bbox": [ + 63, + 219, + 280, + 258 + ], + "type": "text", + "content": "[12] Min Chen, Zhikun Zhang, Tianhao Wang, Michael Backes, Mathias Humbert, and Yang Zhang. Graph unlearning. In Proceedings of the ACM Conference on Computer and Communications Security 2022, 2022. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 63, + 260, + 280, + 289 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 260, + 280, + 289 + ], + "spans": [ + { + "bbox": [ + 63, + 260, + 280, + 289 + ], + "type": "text", + "content": "[13] John M Danskin. The theory of max-min and its application to weapons allocation problems, volume 5. Springer Science & Business Media, 2012. 4" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 63, + 291, + 280, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 291, + 280, + 330 + ], + "spans": [ + { + "bbox": [ + 63, + 291, + 280, + 330 + ], + "type": "text", + "content": "[14] Zhun Deng, Cynthia Dwork, Jialiang Wang, and Linjun Zhang. Interpreting robust optimization via adversarial influence functions. In Proceedings of the 37th International Conference on Machine Learning, volume 119, 2020. 5" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 63, + 332, + 280, + 362 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 332, + 280, + 362 + ], + "spans": [ + { + "bbox": [ + 63, + 332, + 280, + 362 + ], + "type": "text", + "content": "[15] Federal Trade Commission. California company settles ftc allegations it deceived consumers about use of facial recognition in photo storage app, January 2021. 1" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 63, + 363, + 280, + 412 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 363, + 280, + 412 + ], + "spans": [ + { + "bbox": [ + 63, + 363, + 280, + 412 + ], + "type": "text", + "content": "[16] Matt Fredrikson, Somesh Jha, and Thomas Ristenpart. Model inversion attacks that exploit confidence information and basic countermeasures. In Proceedings of the 22nd ACM SIGSAC conference on computer and communications security, pages 1322-1333, 2015. 1" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 63, + 414, + 280, + 434 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 414, + 280, + 434 + ], + "spans": [ + { + "bbox": [ + 63, + 414, + 280, + 434 + ], + "type": "text", + "content": "[17] Regulation (EU) 2016/679 of the European parliament and of the council of 27 April 2016, 2016. 1" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 63, + 435, + 280, + 464 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 435, + 280, + 464 + ], + "spans": [ + { + "bbox": [ + 63, + 435, + 280, + 464 + ], + "type": "text", + "content": "[18] Amirata Ghorbani and James Zou. Data shapley: Equitable valuation of data for machine learning. In International Conference on Machine Learning, pages 2242-2251, 2019. 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 63, + 466, + 280, + 506 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 466, + 280, + 506 + ], + "spans": [ + { + "bbox": [ + 63, + 466, + 280, + 506 + ], + "type": "text", + "content": "[19] Antonio A Ginart, Melody Y Guan, Gregory Valiant, and James Zou. Making ai forget you: data deletion in machine learning. In Proceedings of the 33rd International Conference on Neural Information Processing Systems, 2019. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 63, + 506, + 280, + 546 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 506, + 280, + 546 + ], + "spans": [ + { + "bbox": [ + 63, + 506, + 280, + 546 + ], + "type": "text", + "content": "[20] Jairo Giraldo, Alvaro Cardenas, Murat Kantarcioglu, and Jonathan Katz. Adversarial classification under differential privacy. In Network and Distributed Systems Security (NDSS) Symposium 2020, 2020. 1" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 63, + 548, + 280, + 596 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 548, + 280, + 596 + ], + "spans": [ + { + "bbox": [ + 63, + 548, + 280, + 596 + ], + "type": "text", + "content": "[21] Aditya Golatkar, Alessandro Achille, Avinash Ravichandran, Marzia Polito, and Stefano Soatto. Mixed-privacy forgetting in deep networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 792–801, 2021. 1, 4, 6" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 63, + 599, + 280, + 648 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 599, + 280, + 648 + ], + "spans": [ + { + "bbox": [ + 63, + 599, + 280, + 648 + ], + "type": "text", + "content": "[22] Aditya Golatkar, Alessandro Achille, and Stefano Soatto. Eternal sunshine of the spotless net: Selective forgetting in deep networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9304-9312, 2020. 1, 3, 6, 7, 12" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 63, + 650, + 280, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 650, + 280, + 689 + ], + "spans": [ + { + "bbox": [ + 63, + 650, + 280, + 689 + ], + "type": "text", + "content": "[23] Aditya Golatkar, Alessandro Achille, and Stefano Soatto. Forgetting outside the box: Scrubbing deep networks of information accessible from input-output observations. In European Conference on Computer Vision, 2020. 1, 3, 6" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 63, + 691, + 280, + 710 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 691, + 280, + 710 + ], + "spans": [ + { + "bbox": [ + 63, + 691, + 280, + 710 + ], + "type": "text", + "content": "[24] Ian J. Goodfellow, Jonathon Shlens, and Christian Szegedy. Explaining and harnessing adversarial examples. In Yoshua" + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 299, + 126, + 517, + 710 + ], + "type": "list", + "angle": 0, + "index": 32, + "blocks": [ + { + "bbox": [ + 317, + 126, + 517, + 146 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 126, + 517, + 146 + ], + "spans": [ + { + "bbox": [ + 317, + 126, + 517, + 146 + ], + "type": "text", + "content": "Bengio and Yann LeCun, editors, 3rd International Conference on Learning Representations, 2015. 1, 7" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 299, + 147, + 517, + 196 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 147, + 517, + 196 + ], + "spans": [ + { + "bbox": [ + 299, + 147, + 517, + 196 + ], + "type": "text", + "content": "[25] Roger Grosse, Juhan Bae, Cem Anil, Nelson Elhage, Alex Tamkin, Amirhossein Tajdini, Benoit Steiner, Dustin Li, Esin Durmus, Ethan Perez, et al. Studying large language model generalization with influence functions. arXiv preprint arXiv:2308.03296, 2023. 9" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 299, + 198, + 516, + 237 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 198, + 516, + 237 + ], + "spans": [ + { + "bbox": [ + 299, + 198, + 516, + 237 + ], + "type": "text", + "content": "[26] Chuan Guo, Tom Goldstein, Awni Y. Hannun, and Laurens van der Maaten. Certified data removal from machine learning models. In Proceedings of the 37th International Conference on Machine Learning, 2020. 1, 3, 4, 6, 7" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 299, + 239, + 516, + 269 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 239, + 516, + 269 + ], + "spans": [ + { + "bbox": [ + 299, + 239, + 516, + 269 + ], + "type": "text", + "content": "[27] Jamie Hayes, Borja Balle, and M Pawan Kumar. Learning to be adversarially robust and differentially private. arXiv preprint arXiv:2201.02265, 2022. 1" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 299, + 271, + 517, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 271, + 517, + 330 + ], + "spans": [ + { + "bbox": [ + 299, + 271, + 517, + 330 + ], + "type": "text", + "content": "[28] Dan Hendrycks, Kimin Lee, and Mantas Mazeika. Using pre-training can improve model robustness and uncertainty. In Kamalika Chaudhuri and Ruslan Salakhutdinov, editors, Proceedings of the 36th International Conference on Machine Learning, volume 97 of Proceedings of Machine Learning Research, pages 2712-2721, 09-15 Jun 2019. 6" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 299, + 331, + 517, + 370 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 331, + 517, + 370 + ], + "spans": [ + { + "bbox": [ + 299, + 331, + 517, + 370 + ], + "type": "text", + "content": "[29] Dan Hendrycks, Kimin Lee, and Mantas Mazeika. Using pre-training can improve model robustness and uncertainty. In International Conference on Machine Learning, pages 2712-2721, 2019. 12" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 299, + 373, + 517, + 402 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 373, + 517, + 402 + ], + "spans": [ + { + "bbox": [ + 299, + 373, + 517, + 402 + ], + "type": "text", + "content": "[30] Ruitong Huang, Bing Xu, Dale Schuurmans, and Csaba Szepesvári. Learning with a strong adversary. CoRR, abs/1511.03034, 2015. 1, 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 299, + 404, + 516, + 443 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 404, + 516, + 443 + ], + "spans": [ + { + "bbox": [ + 299, + 404, + 516, + 443 + ], + "type": "text", + "content": "[31] Zachary Izzo, Mary Anne Smart, Kamalika Chaudhuri, and James Zou. Approximate data deletion from machine learning models. In International Conference on Artificial Intelligence and Statistics, pages 2008-2016, 2021. 1, 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 299, + 445, + 517, + 474 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 445, + 517, + 474 + ], + "spans": [ + { + "bbox": [ + 299, + 445, + 517, + 474 + ], + "type": "text", + "content": "[32] Pang Wei Koh and Percy Liang. Understanding black-box predictions via influence functions. In International Conference on Machine Learning, 2017. 5, 7, 12" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 299, + 475, + 517, + 516 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 475, + 517, + 516 + ], + "spans": [ + { + "bbox": [ + 299, + 475, + 517, + 516 + ], + "type": "text", + "content": "[33] Haowen Lin, Jian Lou, Li Xiong, and Cyrus Shahabi. Integer-arithmetic-only certified robustness for quantized neural networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7828-7837, 2021. 1" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 299, + 516, + 517, + 566 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 516, + 517, + 566 + ], + "spans": [ + { + "bbox": [ + 299, + 516, + 517, + 566 + ], + "type": "text", + "content": "[34] Shen Lin, Xiaoyu Zhang, Chenyang Chen, Xiaofeng Chen, and Willy Susilo. Erm-ktp: Knowledge-level machine unlearning via knowledge transfer. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2023. 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 299, + 568, + 517, + 606 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 568, + 517, + 606 + ], + "spans": [ + { + "bbox": [ + 299, + 568, + 517, + 606 + ], + "type": "text", + "content": "[35] Junxu Liu, Jian Lou, Li Xiong, Jinfei Liu, and Xiaofeng Meng. Projected federated averaging with heterogeneous differential privacy. Proceedings of the VLDB Endowment, 15(4):828-840, 2021. 1" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 299, + 608, + 517, + 648 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 608, + 517, + 648 + ], + "spans": [ + { + "bbox": [ + 299, + 608, + 517, + 648 + ], + "type": "text", + "content": "[36] Yang Liu, Mingyuan Fan, Cen Chen, Ximeng Liu, Zhuo Ma, Li Wang, and Jianfeng Ma. Backdoor defense with machine unlearning. In IEEE INFOCOM 2022 - IEEE Conference on Computer Communications, page 280-289, 2022. 1" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 299, + 650, + 517, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 650, + 517, + 689 + ], + "spans": [ + { + "bbox": [ + 299, + 650, + 517, + 689 + ], + "type": "text", + "content": "[37] Jian Lou and Yiu-ming Cheung. An uplink communication-efficient approach to featurewise distributed sparse optimization with differential privacy. IEEE Transactions on Neural Networks and Learning Systems, 32(10):4529-4543, 2020. 1" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 299, + 691, + 517, + 710 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 691, + 517, + 710 + ], + "spans": [ + { + "bbox": [ + 299, + 691, + 517, + 710 + ], + "type": "text", + "content": "[38] Jie Ma, Xiangyuan Lan, Bineng Zhong, Guorong Li, Zhenjun Tang, Xianxian Li, and Rongrong Ji. Robust tracking via" + } + ] + } + ], + "index": 31 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 738, + 297, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 738, + 297, + 746 + ], + "spans": [ + { + "bbox": [ + 279, + 738, + 297, + 746 + ], + "type": "text", + "content": "4901" + } + ] + } + ], + "index": 33 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 62, + 126, + 281, + 710 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 80, + 126, + 281, + 155 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 80, + 126, + 281, + 155 + ], + "spans": [ + { + "bbox": [ + 80, + 126, + 281, + 155 + ], + "type": "text", + "content": "uncertainty-aware semantic consistency. IEEE Transactions on Circuits and Systems for Video Technology, 33(4):1740-1751, 2022. 1" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 63, + 157, + 280, + 197 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 157, + 280, + 197 + ], + "spans": [ + { + "bbox": [ + 63, + 157, + 280, + 197 + ], + "type": "text", + "content": "[39] Aleksander Madry, Aleksandar Makelov, Ludwig Schmidt, Dimitris Tsipras, and Adrian Vladu. Towards deep learning models resistant to adversarial attacks. In 6th International Conference on Learning Representations, 2018. 1, 7" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 62, + 198, + 280, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 198, + 280, + 228 + ], + "spans": [ + { + "bbox": [ + 62, + 198, + 280, + 228 + ], + "type": "text", + "content": "[40] Ananth Mahadevan and Michael Mathioudakis. Certifiable machine unlearning for linear models. arXiv preprint arXiv:2106.15093, 2021. 3, 7" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 63, + 229, + 280, + 269 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 229, + 280, + 269 + ], + "spans": [ + { + "bbox": [ + 63, + 229, + 280, + 269 + ], + "type": "text", + "content": "[41] Neil G Marchant, Benjamin IP Rubinstein, and Scott Alfeld. Hard to forget: Poisoning attacks on certified machine unlearning. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 7691-7700, 2022. 1" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 63, + 270, + 280, + 310 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 270, + 280, + 310 + ], + "spans": [ + { + "bbox": [ + 63, + 270, + 280, + 310 + ], + "type": "text", + "content": "[42] Brendan McMahan, Eider Moore, Daniel Ramage, Seth Hampson, and Blaise Aguera y Arcas. Communication-efficient learning of deep networks from decentralized data. In Artificial intelligence and statistics, 2017. 1" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 63, + 311, + 280, + 360 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 311, + 280, + 360 + ], + "spans": [ + { + "bbox": [ + 63, + 311, + 280, + 360 + ], + "type": "text", + "content": "[43] Ronak Mehta, Sourav Pal, Vikas Singh, and Sathya N. Ravi. Deep unlearning via randomized conditionally independent hessian. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 10422-10431, June 2022. 1, 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 63, + 362, + 280, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 362, + 280, + 392 + ], + "spans": [ + { + "bbox": [ + 63, + 362, + 280, + 392 + ], + "type": "text", + "content": "[44] Seth Neel, Aaron Roth, and Saeed Sharifi-Malvajerdi. Descent-to-delete: Gradient-based methods for machine unlearning. In Algorithmic Learning Theory, 2021. 1" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 63, + 394, + 280, + 433 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 394, + 280, + 433 + ], + "spans": [ + { + "bbox": [ + 63, + 394, + 280, + 433 + ], + "type": "text", + "content": "[45] Nicolas Papernot, Patrick McDaniel, Arunesh Sinha, and Michael P Wellman. Sok: Security and privacy in machine learning. In 2018 IEEE European Symposium on Security and Privacy (EuroS&P), pages 399-414. IEEE, 2018. 1" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 63, + 435, + 280, + 463 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 435, + 280, + 463 + ], + "spans": [ + { + "bbox": [ + 63, + 435, + 280, + 463 + ], + "type": "text", + "content": "[46] Jian Pei. A survey on data pricing: from economics to data science. IEEE Transactions on knowledge and Data Engineering, 2020. 5" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 63, + 465, + 280, + 505 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 465, + 280, + 505 + ], + "spans": [ + { + "bbox": [ + 63, + 465, + 280, + 505 + ], + "type": "text", + "content": "[47] Hai Phan, My T Thai, Han Hu, Ruoming Jin, Tong Sun, and Dejing Dou. Scalable differential privacy with certified robustness in adversarial learning. In International Conference on Machine Learning, pages 7683-7694, 2020. 1" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 63, + 506, + 280, + 566 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 506, + 280, + 566 + ], + "spans": [ + { + "bbox": [ + 63, + 506, + 280, + 566 + ], + "type": "text", + "content": "[48] NhatHai Phan, Minh N. Vu, Yang Liu, Ruoming Jin, Dejing Dou, Xintao Wu, and My T. Thai. Heterogeneous gaussian mechanism: Preserving differential privacy in deep learning with provable robustness. In Sarit Kraus, editor, Proceedings of the Twenty-Eighth International Joint Conference on Artificial Intelligence, pages 4753-4759, 2019. 1" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 63, + 567, + 280, + 607 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 567, + 280, + 607 + ], + "spans": [ + { + "bbox": [ + 63, + 567, + 280, + 607 + ], + "type": "text", + "content": "[49] Ayush Sekhari, Jayadev Acharya, Gautam Kamath, and Ananda Theertha Suresh. Remember what you want to forget: Algorithms for machine unlearning. Advances in Neural Information Processing Systems, 34:18075-18086, 2021. 3, 4" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 63, + 607, + 280, + 648 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 607, + 280, + 648 + ], + "spans": [ + { + "bbox": [ + 63, + 607, + 280, + 648 + ], + "type": "text", + "content": "[50] Uri Shaham, Yutaro Yamada, and Sahand Negahban. Understanding adversarial training: Increasing local stability of supervised models through robust optimization. Neurocomputing, 307:195-204, 2018. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 63, + 650, + 280, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 650, + 280, + 689 + ], + "spans": [ + { + "bbox": [ + 63, + 650, + 280, + 689 + ], + "type": "text", + "content": "[51] Reza Shokri, Marco Stronati, Congzheng Song, and Vitaly Shmatikov. Membership inference attacks against machine learning models. In 2017 IEEE Symposium on Security and Privacy, pages 3-18. IEEE, 2017. 1" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 63, + 690, + 280, + 710 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 690, + 280, + 710 + ], + "spans": [ + { + "bbox": [ + 63, + 690, + 280, + 710 + ], + "type": "text", + "content": "[52] Liwei Song, Reza Shokri, and Prateek Mittal. Privacy risks of securing machine learning models against adversarial exam" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 299, + 126, + 517, + 708 + ], + "type": "list", + "angle": 0, + "index": 31, + "blocks": [ + { + "bbox": [ + 317, + 126, + 516, + 145 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 126, + 516, + 145 + ], + "spans": [ + { + "bbox": [ + 317, + 126, + 516, + 145 + ], + "type": "text", + "content": "plies. In Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security, 2019. 1" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 299, + 147, + 517, + 197 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 147, + 517, + 197 + ], + "spans": [ + { + "bbox": [ + 299, + 147, + 517, + 197 + ], + "type": "text", + "content": "[53] Qiheng Sun, Xiang Li, Jiayao Zhang, Li Xiong, Weiran Liu, Jinfei Liu, Zhan Qin, and Kui Ren. Shapleyfl: Robust federated learning based on shapley value. In Proceedings of the 29th ACM SIGKDD Conference on Knowledge Discovery and Data Mining, pages 2096-2108, 2023. 1" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 299, + 197, + 517, + 245 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 197, + 517, + 245 + ], + "spans": [ + { + "bbox": [ + 299, + 197, + 517, + 245 + ], + "type": "text", + "content": "[54] Christian Szegedy, Wojciech Zaremba, Ilya Sutskever, Joan Bruna, Dumitru Erhan, Ian J. Goodfellow, and Rob Fergus. Intriguing properties of neural networks. In Yoshua Bengio and Yann LeCun, editors, 2nd International Conference on Learning Representations, 2014. 1" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 299, + 246, + 517, + 286 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 246, + 517, + 286 + ], + "spans": [ + { + "bbox": [ + 299, + 246, + 517, + 286 + ], + "type": "text", + "content": "[55] Farnaz Tahmasebian, Jian Lou, and Li Xiong. Robustfed: a truth inference approach for robust federated learning. In Proceedings of the 31st ACM International Conference on Information & Knowledge Management, 2022. 1" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 299, + 287, + 517, + 326 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 287, + 517, + 326 + ], + "spans": [ + { + "bbox": [ + 299, + 287, + 517, + 326 + ], + "type": "text", + "content": "[56] Pengfei Tang, Wenjie Wang, Jian Lou, and Li Xiong. Generating adversarial examples with distance constrained adversarial imitation networks. IEEE Transactions on Dependable and Secure Computing, 19(6):4145-4155, 2021." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 299, + 327, + 517, + 375 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 327, + 517, + 375 + ], + "spans": [ + { + "bbox": [ + 299, + 327, + 517, + 375 + ], + "type": "text", + "content": "[57] Anvith Thudi, Gabriel Deza, Varun Chandrasekaran, and Nicolas Papernot. Unrolling sgd: Understanding factors influencing machine unlearning. In 2022 IEEE 7th European Symposium on Security and Privacy (EuroS&P), pages 303-319. IEEE, 2022. 4" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 299, + 377, + 517, + 416 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 377, + 517, + 416 + ], + "spans": [ + { + "bbox": [ + 299, + 377, + 517, + 416 + ], + "type": "text", + "content": "[58] Anvith Thudi, Hengrui Jia, Ilia Shumailov, and Nicolas Papernot. On the necessity of auditable algorithmic definitions for machine unlearning. In 31st USENIX Security Symposium (USENIX Security 22), pages 4007-4022, 2022. 1" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 299, + 417, + 517, + 457 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 417, + 517, + 457 + ], + "spans": [ + { + "bbox": [ + 299, + 417, + 517, + 457 + ], + "type": "text", + "content": "[59] Boxi Wu, Jindong Gu, Zhifeng Li, Deng Cai, Xiaofei He, and Wei Liu. Towards efficient adversarial training on vision transformers. In European Conference on Computer Vision, pages 307-325, 2022. 1" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 299, + 458, + 517, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 458, + 517, + 487 + ], + "spans": [ + { + "bbox": [ + 299, + 458, + 517, + 487 + ], + "type": "text", + "content": "[60] Yinjun Wu, Edgar Dobriban, and Susan Davidson. Deltagrad: Rapid retraining of machine learning models. In International Conference on Machine Learning, 2020. 1, 4" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 299, + 488, + 517, + 527 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 488, + 517, + 527 + ], + "spans": [ + { + "bbox": [ + 299, + 488, + 517, + 527 + ], + "type": "text", + "content": "[61] Jingwen Ye, Yifang Fu, Jie Song, Xingyi Yang, Songhua Liu, Xin Jin, Mingli Song, and Xinchao Wang. Learning with recoverable forgetting. In European Conference on Computer Vision, pages 87-103, 2022. 1" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 299, + 527, + 517, + 566 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 527, + 517, + 566 + ], + "spans": [ + { + "bbox": [ + 299, + 527, + 517, + 566 + ], + "type": "text", + "content": "[62] Xiaoyong Yuan, Pan He, Qile Zhu, and Xiaolin Li. Adversarial examples: Attacks and defenses for deep learning. IEEE transactions on neural networks and learning systems, 30(9):2805-2824, 2019. 1" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 299, + 567, + 517, + 586 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 567, + 517, + 586 + ], + "spans": [ + { + "bbox": [ + 299, + 567, + 517, + 586 + ], + "type": "text", + "content": "[63] Sergey Zagoruyko and Nikos Komodakis. Wide residual networks. In British Machine Vision Conference, 2016. 6" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 299, + 587, + 517, + 617 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 587, + 517, + 617 + ], + "spans": [ + { + "bbox": [ + 299, + 587, + 517, + 617 + ], + "type": "text", + "content": "[64] Guojun Zhang, Kaiwen Wu, Pascal Poupart, and Yaoliang Yu. Newton-type methods for minimax optimization. arXiv preprint arXiv:2006.14592, 2020. 5" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 299, + 618, + 517, + 656 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 618, + 517, + 656 + ], + "spans": [ + { + "bbox": [ + 299, + 618, + 517, + 656 + ], + "type": "text", + "content": "[65] Peng-Fei Zhang, Guangdong Bai, Zi Huang, and Xin-Shun Xu. Machine unlearning for image retrieval: A generative scrubbing approach. In Proceedings of the 30th ACM International Conference on Multimedia, 2022. 1" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 299, + 657, + 517, + 708 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 657, + 517, + 708 + ], + "spans": [ + { + "bbox": [ + 299, + 657, + 517, + 708 + ], + "type": "text", + "content": "[66] Xiaoyu Zhang, Yulin Jin, Tao Wang, Jian Lou, and Xiaofeng Chen. Purifier: Plug-and-play backdoor mitigation for pretrained models via anomaly activation suppression. In Proceedings of the 30th ACM International Conference on Multimedia, pages 4291-4299, 2022. 1" + } + ] + } + ], + "index": 30 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "spans": [ + { + "bbox": [ + 279, + 738, + 298, + 746 + ], + "type": "text", + "content": "4902" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/0f77204f-207d-45fd-9794-f340dac7f292_content_list.json b/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/0f77204f-207d-45fd-9794-f340dac7f292_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..55881552f9bab24cfa9b2c83c70af84988a89e4f --- /dev/null +++ b/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/0f77204f-207d-45fd-9794-f340dac7f292_content_list.json @@ -0,0 +1,1623 @@ +[ + { + "type": "text", + "text": "MV-DeepSDF: Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving", + "text_level": 1, + "bbox": [ + 156, + 130, + 818, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Yibo Liu $^{1,2}$ , Kelly Zhu $^{1,3}$ , Guile Wu $^{1}$ , Yuan Ren $^{1}$ , Bingbing Liu $^{1}$ , Yang Liu $^{1}$ , Jinjun Shan $^{2}$ $^{1}$ Huawei Noah's Ark Lab, $^{2}$ York University, $^{3}$ University of Toronto", + "bbox": [ + 132, + 202, + 836, + 239 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{yorklyb, jjshan}@yorku.ca, kellyk.zhu@mail.utoronto.ca \n{guile.wu, yuan.ren3, liu.bingbing, yang.liu9}@huawei.com", + "bbox": [ + 230, + 241, + 736, + 273 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 308, + 313, + 325 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Reconstructing 3D vehicles from noisy and sparse partial point clouds is of great significance to autonomous driving. Most existing 3D reconstruction methods cannot be directly applied to this problem because they are elaborately designed to deal with dense inputs with trivial noise. In this work, we propose a novel framework, dubbed MV-DeepSDF, which estimates the optimal Signed Distance Function (SDF) shape representation from multisweep point clouds to reconstruct vehicles in the wild. Although there have been some SDF-based implicit modeling methods, they only focus on single-view-based reconstruction, resulting in low fidelity. In contrast, we first analyze multi-sweep consistency and complementarity in the latent feature space and propose to transform the implicit space shape estimation problem into an element-to-set feature extraction problem. Then, we devise a new architecture to extract individual element-level representations and aggregate them to generate a set-level predicted latent code. This set-level latent code is an expression of the optimal 3D shape in the implicit space, and can be subsequently decoded to a continuous SDF of the vehicle. In this way, our approach learns consistent and complementary information among multi-sweeps for 3D vehicle reconstruction. We conduct thorough experiments on two real-world autonomous driving datasets (Waymo and KITTI) to demonstrate the superiority of our approach over state-of-the-art alternative methods both qualitatively and quantitatively.", + "bbox": [ + 76, + 342, + 473, + 750 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 782, + 209, + 797 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "3D vehicle reconstruction from sparse and partial point clouds is a fundamental need in the autonomous driving industry [12, 17]. It aims to infer the 3D structure of vehicles at arbitrary resolutions in the wild, which is of great significance to many downstream tasks in autonomous driving. Despite the many 3D reconstruction methods", + "bbox": [ + 75, + 809, + 470, + 901 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/874358cfe3f7daf165f03b2f783a448991beac9a618f340f6a9ce7612a90a3b7.jpg", + "image_caption": [ + "Figure 1. An illustration of the motivation of the proposed approach. Our approach takes multi-sweep point clouds as input and simplifies 3D vehicle reconstruction from multi-sweeps into an element-to-set feature extraction problem. In this way, we infer an optimal estimation of the 3D shape described in the abstract implicit space for 3D vehicle reconstruction in autonomous driving." + ], + "image_footnote": [], + "bbox": [ + 504, + 308, + 893, + 415 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "[28, 35, 26, 39, 41, 1, 19, 4], most of them focus on image-based inputs [28, 35, 26, 39, 41], dense point cloud inputs [19, 31, 11], or their combination [1, 4, 9] and thus, cannot be directly applied to this problem.", + "bbox": [ + 496, + 532, + 893, + 594 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Recently, [12] has shown promising performance in applying implicit modeling to tackle this problem. Contrary to explicit modeling methods [32, 33, 47, 49, 43, 42, 10, 2, 38] that directly represent 3D object shape structure with points, voxels, or meshes, implicit modeling maps the 3D shape to a low-dimensional latent space and learns the projection from the latent space to a continuous function that describes the 3D shape. This presents two significant advantages: 1) the 3D shape can be stored as a low-dimensional memory-saving latent code [31, 11, 12, 6]; 2) the trained network outputs a continuous function in the 3D space which supports mesh extraction at any resolution [31]. To this end, we also choose to employ implicit modeling in our approach.", + "bbox": [ + 496, + 595, + 895, + 792 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "However, previous point cloud-based implicit modeling methods [31, 11, 12] mainly focus on recovering 3D shapes from a single-view partial point cloud and fail to leverage the multi-sweep information of vehicles. As a result, when noise or annotation errors exist in an individual sweep, single-view methods usually produce low fidelity results. In real-world datasets (e.g., [36, 15]), multi-sweep", + "bbox": [ + 496, + 795, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "8306", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/acd7e7eb2dd647e7a79fcc94f31d1ee273b2517b306db0ad51afc76a748c7b6d.jpg", + "image_caption": [ + "Figure 2. The framework of the proposed MV-DeepSDF. Farthest Point Sampling (FPS) [33] is applied to the raw point clouds for preprocessing and DeepSDF [31] is employed to generate a latent code for each observation. We then extract global features from the standardized point clouds (refer to yellow block) and concatenate the global features with the latent codes as element-level representations. Next, the element-level representations are transformed into a set-level predicted latent code (refer to red block). Finally, we employ a pre-trained DeepSDF decoder [31] to project the predicted latent code to the SDF of the vehicle in 3D space and recover the 3D mesh. Note that the decoder used in the final step (refer to white trapezoid) is identical to that of DeepSDF (refer to green block)." + ], + "image_footnote": [], + "bbox": [ + 78, + 87, + 893, + 313 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "point clouds are usually available and contain richer shape information because of the various viewing angles offered by multiple observations [17]. Although there are some existing 3D reconstruction methods from multi-view point clouds [17, 19, 3, 34], implicit modeling with multi-sweep point clouds remains an unsolved problem.", + "bbox": [ + 75, + 426, + 468, + 516 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this work, we propose a novel framework, dubbed MV-DeepSDF, to exploit multi-sweep point clouds and implicitly generate high-fidelity 3D reconstructions of vehicles for autonomous driving. An illustration of the motivation for our proposed approach is depicted in Figure 1. Specifically, to shed light on the importance of exploring multi-sweep point clouds for 3D vehicle reconstruction, we first analyze multi-sweep consistency and complementarity in the latent feature space. We then propose to consider the problem of shape estimation in the implicit space as an element-to-set feature extraction problem, where a set represents a collection of multi-sweeps and an element represents a sparse and partial point cloud. Next, we devise a new architecture to simultaneously extract a global feature and latent code for each element in the multi-sweep and concatenate them as element-level representations. These element-level representations are then transformed into a set-level predicted latent code with the aid of average pooling and mapping. This set-level latent code is an optimal estimation of the 3D shape described in the abstract implicit space, which we subsequently decode to a continuous SDF of the vehicle with a pre-trained DeepSDF decoder [31] and recover the 3D mesh from the SDF. The contributions of this work are threefold:", + "bbox": [ + 75, + 517, + 470, + 878 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We analyze multi-sweep consistency and complement", + "bbox": [ + 93, + 885, + 470, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "tarity in the latent feature space and transform the problem of shape estimation in the implicit space into an element-to-set feature extraction problem. This simplifies 3D vehicle reconstruction from multi-sweep point clouds into an optimal estimation of the 3D shape described in the abstract implicit space.", + "bbox": [ + 529, + 426, + 890, + 517 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose a novel MV-DeepSDF framework (see Figure 2) for implicit modeling with multi-sweep point clouds. A new architecture is constructed to extract the element-level representations and generate the set-level predicted latent code.", + "- We qualitatively and quantitatively demonstrate the superior performance of our approach over the state-of-the-art alternative methods through extensive experiments on real-world datasets [36, 15]." + ], + "bbox": [ + 514, + 531, + 893, + 681 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 699, + 640, + 714 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Explicit Modeling-Based 3D Reconstruction", + "text_level": 1, + "bbox": [ + 500, + 724, + 872, + 741 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Conventional 3D explicit modeling can be classified into three categories, namely point-based [32, 33, 47, 49, 43], voxel-based [42, 10], and mesh-based [2, 38]. Point-based methods, such as Point Completion Network (PCN) [49], GRNet [43], and PoinTr [47], output a point cloud with limited resolution since the number of points is fixed and not suitable for generating watertight surfaces due to lack of topology description. Voxel-based methods [42, 10] describe volumes by subdividing the space into a 3D grid, but they are memory and compute intensive, leading to slow", + "bbox": [ + 496, + 750, + 890, + 901 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "8307", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "training and low resolution representations [31]. Mesh-based methods only generate meshes with simple topologies [40] given by a fixed reference template from the same object class and cannot guarantee watertight surfaces [22, 16]. In contrast, we propose implicit modeling with multi-sweep point clouds in a novel MV-DeepSDF framework, which estimates the optimal SDF shape representation for reconstructing 3D structures of vehicles in autonomous driving.", + "bbox": [ + 75, + 90, + 472, + 227 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Implicit Modeling-Based 3D Reconstruction", + "text_level": 1, + "bbox": [ + 76, + 238, + 452, + 255 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Implicit modeling [27, 31, 11, 12] uses function-based decision boundaries to implicitly define surfaces for 3D representations. DeepSDF [31] is a classical approach to implicit modeling. It estimates the Signed Distance Function (SDF) of an object from a partial point cloud, where the SDF specifies whether a querying position is inside or outside the surface of the object and the distance of the querying position from the surface. There have been some improved versions [11, 12, 6, 45] of DeepSDF, but these methods only focus on 3D reconstruction from a single-view point cloud and thus, generally produce low fidelity results when noise or annotation errors exist in an individual sweep. In contrast, we propose a novel framework for implicit modeling with multi-sweep point clouds. We analyze multi-sweep consistency and complementarity in the latent feature space and propose to resolve this problem by an optimal estimation of the 3D shape described in the abstract implicit space. Moreover, other implicit modeling-based methods, such as Neural Radiance Fields (NeRF) [28], Point-NeRF [44], Direct Voxel Grid Optimization [35], NeuS [41], NEAT [26], and [1, 4, 9] exist, but they all require image input and cannot deal with only LiDAR data.", + "bbox": [ + 75, + 261, + 472, + 609 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.3. Multi-View 3D Reconstruction", + "text_level": 1, + "bbox": [ + 76, + 619, + 349, + 636 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3D reconstruction from multi-view point clouds can be categorized into conventional approaches [3, 34, 29] and deep learning-based approaches [17, 19, 5]. Conventional geometric approaches, such as Iterative Closest Point (ICP), TSDF [29], and [3, 34], only leverage multi-view observations geometrically, so the resulting completion is merely an aligned stack of partial point clouds and cannot produce watertight shapes unless the sensor fully loops around the object. In deep learning-based approaches, [17] proposes a weakly-supervised framework to directly learn 3D shape completion from multi-view LiDAR sweeps, but its reconstruction result is not watertight. [19] presents a shape completion framework using a multi-view depth map-based shape representation approach, while [5] designs a network to use multiple partial point clouds encoded into the latent space to estimate the optimal shape of the object. However, the output of these networks [19, 5] are point-based repre", + "bbox": [ + 75, + 643, + 472, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "sentations and in contrast with continuous field functions such as SDFs [31], lack continuity in 3D space. Moreover, some methods, such as [13, 14, 46], exist for reconstructing vehicle shapes from multiple observations, but [13] relies on stereo images and motion priors to regularize the shape estimation of vehicles, [14] requires multi-view camera images to build semantic maps which contain 3D vehicle shapes, and [46] requires inputs to follow a time sequence to track and reconstruct 3D objects. In contrast, our approach simplifies 3D vehicle reconstruction from multisweep point clouds into an optimal estimation of the 3D shape described in the abstract implicit space, which supports mesh extraction at any resolution and can deal with noise and annotation errors that exist in an individual sweep.", + "bbox": [ + 496, + 90, + 893, + 303 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Methodology", + "text_level": 1, + "bbox": [ + 500, + 316, + 635, + 333 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Preliminaries", + "text_level": 1, + "bbox": [ + 500, + 340, + 640, + 354 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this section, we introduce preliminaries regarding DeepSDF [31] since our approach utilizes its framework for extracting the latent code and decoding the continuous SDF for 3D mesh generation. Formally, when adopting the DeepSDF decoder into the shape completion task, points of partial point clouds are taken as given surface points and the SDF value is defined as the distance from the querying point to the surface of the object. Interior and exterior querying points are sampled along the normals of the surface points and the SDF value is computed for each querying point. Suppose the set of newly sampled interior and exterior points is denoted as $\\mathcal{P}_{\\mathcal{M}}$ , where $M$ is the number of points. Define the $m$ th point in $\\mathcal{P}_{\\mathcal{M}}$ as $\\pmb{x}_m$ and its corresponding SDF value as $s_m$ . In the domain of DeepSDF [31], a 3D shape can be represented by a latent code $z \\in \\mathbb{R}^{256}$ in the latent space. The complete shape is obtained by optimizing $z$ via Maximum a Posterior estimation:", + "bbox": [ + 496, + 363, + 893, + 621 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {z} = \\frac {1}{\\sigma^ {2}} \\| z \\| _ {2} ^ {2} + \\underset {\\boldsymbol {z}} {\\arg \\min } \\sum_ {m = 1} ^ {M} \\mathcal {L} _ {1} \\left(f _ {\\theta} \\left(\\boldsymbol {z}, \\boldsymbol {x} _ {m}\\right), s _ {m}\\right), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 514, + 631, + 890, + 671 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\mathcal{L}_1$ represents the clamped $\\mathcal{L}_1$ distance and $\\sigma$ is a regularization hyperparameter. Once the optimal latent code $\\hat{\\boldsymbol{z}}$ is determined, the complete 3D shape can be recovered by finding the zero-SDF-value isosurface through the DeepSDF decoder $f(\\cdot)$ , which is defined as:", + "bbox": [ + 496, + 681, + 893, + 757 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {s} = f _ {\\theta} (\\hat {\\boldsymbol {z}}, \\boldsymbol {x}), \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 643, + 768, + 890, + 785 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\theta$ represents the parameters of the decoder, $\\pmb{x} \\in \\mathbb{R}^3$ denotes the 3D coordinates of the querying point, and $\\hat{s}$ denotes the estimated SDF value given by $f(\\cdot)$ . Here, the sign of $\\hat{s}$ , either positive or negative, indicates whether the point lies on the exterior or interior of the surface, respectively. Thus, the surface of the object can be implicitly represented by the isosurface composed of points with zero SDF values.", + "bbox": [ + 496, + 794, + 893, + 902 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "8308", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Despite its simplicity and efficiency, DeepSDF only takes the given surface points into consideration when generating 3D shapes (i.e., Eq. (1)). This can lead to suboptimal reconstruction results in areas not captured by the partial point clouds since DeepSDF will reconstruct arbitrarily based on prior knowledge learned during training. For instance, referencing the ground truth of Case 1 in Figure 3, the reconstruction results of DeepSDF for Cases 2, 3, and 4 only demonstrate high fidelity in areas with well-captured surface points. The missing areas are reconstructed arbitrarily. To resolve this problem, we analyze multi-sweep consistency and complementarity in the latent feature space and propose implicit modeling with multi-sweep point clouds in MV-DeepSDF.", + "bbox": [ + 75, + 90, + 472, + 303 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Approach Overview", + "text_level": 1, + "bbox": [ + 76, + 313, + 267, + 329 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "As shown in Figure 2, there are three main steps in MV-DeepSDF, namely preprocessing, optimal latent code prediction, and 3D mesh extraction.", + "bbox": [ + 75, + 335, + 468, + 381 + ], + "page_idx": 3 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1) Preprocessing. First, we carry out Farthest Point Sampling (FPS) [33] to sample a fixed number of points on each raw partial point cloud since our global feature extractor requires standardized point clouds as input. For FPS, the number of centroids is set as 256.", + "2) Optimal Latent Code Prediction. The post-FPS point clouds are used as input into the global feature extractor (yellow block in Figure 2) to extract global features for each individual point cloud. Meanwhile, the original point clouds are used to extract latent codes for each partial point cloud through the pre-trained DeepSDF (green block in Figure 2). Then, as shown in the red block of Figure 2, the global features and latent codes are concatenated as element-level representations, followed by an average pooling operation to aggregate the information into a single instance tensor. Finally, this instance tensor is transformed into the predicted latent code by a fully-connected layer as the set-level representation.", + "3) 3D Mesh Extraction. The predicted latent code is converted to an SDF using a pre-trained DeepSDF decoder [31]. The isosurface composed of querying points with zero SDF values represents the surface of the instance and the implicit surface can be rasterized to a 3D mesh using Marching Cubes [24]. Since the SDF is a continuous function, it supports 3D mesh extraction at any resolution." + ], + "bbox": [ + 75, + 382, + 468, + 760 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Consistency and Complementarity Analysis", + "text_level": 1, + "bbox": [ + 76, + 770, + 449, + 787 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Background. In literature [37, 50], multi-view consistency refers to the consistency of describing the same instance from different viewpoint observations and multi-view complementarity refers to the complementary information of the same instance provided by different observations. Existing methods mainly explore multi-view consistency and complementarity for 3D reconstruction with par", + "bbox": [ + 75, + 794, + 468, + 901 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/d98b3d4102529c6d45a9201561ab4f13c29f0577e2ea222a69168be1c16f3a27.jpg", + "image_caption": [ + "Figure 3. The 3D reconstruction results of DeepSDF [31] (row 2) using different point clouds (row 1). All point clouds are sampled from the same CAD model of ShapeNetV2 [7]. Case 1 shows the complete dense point cloud used to train the DeepSDF decoder, while Cases 2, 3, and 4 show the partial point clouds." + ], + "image_footnote": [], + "bbox": [ + 506, + 89, + 879, + 189 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "tial point clouds in explicit modeling [34, 3].", + "bbox": [ + 498, + 291, + 795, + 306 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "However, existing methods are not applicable for exploring multi-sweep/-view consistency and complementarity in implicit modeling because the abstract feature space operates differently than the explicit space. In implicit modeling, point clouds are expressed as low-dimensional feature vectors (a.k.a. latent vectors) in the latent feature space and the latent vectors are generated through a non-linear learning process that projects the 3D space to the feature space through a deep neural network [31, 32, 33, 49].", + "bbox": [ + 496, + 306, + 890, + 443 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Theoretical Analysis. Despite these differences, we can still explore multi-sweep consistency and complementarity in the latent feature space for implicit modeling. Inspired by [25], consider a total of $B$ observations. The latent code for the $i$ th observation, denoted by $z_{i}$ , can be represented as:", + "bbox": [ + 496, + 460, + 892, + 549 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {z} _ {i} = \\boldsymbol {z} _ {i, c} + \\boldsymbol {z} _ {i, s} + \\boldsymbol {e} _ {i}, \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 619, + 551, + 890, + 566 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $i = \\{1,\\dots ,B\\}$ $z_{i,c}$ is the consistent component, $z_{i,s}$ is the specific component, and $e_i$ is the error component. In this work, $z_{i,c}$ and $z_{i,s}$ can be defined as follows:", + "bbox": [ + 498, + 574, + 890, + 619 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {z} _ {i, c} = \\boldsymbol {z} _ {i} \\cap \\boldsymbol {z} _ {g t} \\quad \\text {a n d} \\quad \\left(\\boldsymbol {z} _ {i, s} + \\boldsymbol {e} _ {i}\\right) = \\boldsymbol {z} _ {g t} - \\boldsymbol {z} _ {i}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 524, + 647, + 890, + 662 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbf{z}_{gt}$ is the latent code corresponding to the ground truth shape and '∩' and '−' represent the similarity and difference in information captured by the two feature vectors, respectively. Now, consider any two consistent components $\\mathbf{z}_{i,c}$ and $\\mathbf{z}_{j,c}$ . In the first case where $\\mathbf{z}_{i,c} \\cap \\mathbf{z}_{j,c} = \\emptyset$ , the two components contain completely different consistent information, which is complementary. In the second case where $\\mathbf{z}_{i,c} \\cap \\mathbf{z}_{j,c} \\neq \\emptyset$ , but $\\mathbf{z}_{i,c} \\nsubseteq \\mathbf{z}_{j,c}$ and $\\mathbf{z}_{j,c} \\nsubseteq \\mathbf{z}_{i,c}$ , the two components contain some different information, which can be aggregated as complementary information to approach the ground truth. In the final case where $\\mathbf{z}_{i,c} \\cap \\mathbf{z}_{j,c} \\neq \\emptyset$ , but $\\mathbf{z}_{i,c} \\subseteq \\mathbf{z}_{j,c}$ or $\\mathbf{z}_{j,c} \\subseteq \\mathbf{z}_{i,c}$ , either $\\mathbf{z}_{i,c}$ or $\\mathbf{z}_{j,c}$ contains redundant information from the other component. While redundant, this will not adversely impact complementary aggregation. Thus, to make the optimal $\\hat{\\mathbf{z}}$ approach the ground", + "bbox": [ + 496, + 674, + 892, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "8309", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "truth $z_{gt}$ , it is desired to aggregate all consistent and complementary information among all individual features:", + "bbox": [ + 76, + 90, + 468, + 121 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {z} = z _ {1, c} \\cup z _ {2, c} \\dots \\cup z _ {B, c} + p, \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 166, + 133, + 468, + 150 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\cup$ refers to the complementary aggregation of information among features and $p$ denotes the predicted information for regions not captured in the multi-sweeps (e.g., the side of the vehicle not captured by the multi-sweeps as shown in the Cases 3 and 4 of Figure 3). In summary, with implicit modeling, we can learn the optimal latent code $\\hat{z}$ by aggregating consistent (Eqs. (3)-(4)) and complementary (Eq. (5)) information among multi-sweeps.", + "bbox": [ + 76, + 162, + 468, + 282 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.4. Architecture Design of MV-DeepSDF", + "text_level": 1, + "bbox": [ + 76, + 292, + 397, + 309 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To take advantage of multi-sweep consistency and complementarity in the latent feature space, we design a new architecture for implicit modeling. Our proposed architecture uses multi-sweep point clouds as model input and generates an optimal estimation of the 3D shape in the implicit space (a.k.a. the optimal latent code) as the output. The functionality of the network can be formulated as:", + "bbox": [ + 76, + 316, + 468, + 421 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\ng _ {\\alpha} (\\boldsymbol {Z}, \\boldsymbol {P}) = \\hat {\\boldsymbol {z}} \\rightarrow \\boldsymbol {z} _ {g t}, \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 192, + 434, + 468, + 450 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $g(\\cdot)$ denotes the desired network with associated parameters $\\alpha, Z = \\{z_1, \\dots, z_B\\}$ denotes the set of latent codes, $B$ represents the number of observations or latent codes, $P = \\{\\mathcal{P}_1, \\dots, \\mathcal{P}_B\\}$ denotes the set of multi-view point clouds, and $\\hat{z} \\in \\mathbb{R}^{256}$ and $z_{gt} \\in \\mathbb{R}^{256}$ represent the estimated optimal and ground truth latent codes, respectively. Hence, the goal is converted into learning a network to make $\\hat{z}$ approach $z_{gt}$ for subsequent reconstructions. To this end, we devise a new architecture to realize the functionality required by simultaneously learning global features and latent codes for generating predicted latent codes.", + "bbox": [ + 75, + 462, + 468, + 628 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Specifically, inspired by PointNet [32], a pioneering work for 3D classification and segmentation, we transform the problem of shape estimation in the implicit space into an element-to-set feature extraction problem. Given a point cloud containing a set of 3D points, where all 3D points consistently describe a single object since they all belong to the same instance, we can learn a global feature for each point cloud that aggregates complementary features from each individual 3D point. However, only learning a global feature cannot be used for 3D reconstruction, so we propose to abstract the pipeline of PointNet (see Figure 4(a)) into a generalized process (see Figure 4(b)). As shown in Figure 4(a), PointNet first computes 3D point features using a shared MLP on each 3D point and then transforms these point features into a single global feature through max pooling. Now, suppose there exists a set composed of multiple elements. The goal of the generalized pipeline is to extract a feature for the entire set by aggregating all elements. To this", + "bbox": [ + 75, + 628, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/8655a99fe17b13bed1cc115fd249231c3ead10cf94e87828c2ebf5cfd65ea4e2.jpg", + "image_caption": [ + "Figure 4. Comparison of three pipelines. (a) The pipeline of PointNet [32]. (b) The pipeline of an abstract generalized process to extract the set feature from the elements. (c) The proposed pipeline to extract the instance feature from multi-sweep point clouds." + ], + "image_footnote": [], + "bbox": [ + 501, + 88, + 890, + 214 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "end, we propose two generalized operations. As shown in Figure 4(b), we define operation 1 as the computation of the element features (e.g., the shared MLP in PointNet) and operation 2 as the transformation of the element features into a set feature (e.g., the max pooling operation in PointNet).", + "bbox": [ + 496, + 305, + 890, + 380 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Using this generalized process, we can now devise our architecture to simultaneously learn global features and latent codes for generating predicted latent codes. First, we construct a global feature extractor (see yellow block in Figure 2) for learning a global feature for each point cloud that aggregates complementary features from each individual 3D point. The architecture of this feature extractor is inspired by the PCN encoder [49], a variant of PointNet [32]. This block is a stack of four PointNet [32] encoders with 128, 256, 512, and 1024 units, respectively. Since this architecture is inspired by the PCN encoder [49] and its global feature extraction operation is applied to every individual point cloud, we name it shared PCN. Meanwhile, to exploit the implicit information of each element, we employ a pre-trained DeepSDF [31] model (as denoted by Eq. (1)) to generate a latent code for each partial point cloud. Next, we concatenate the global features and latent codes to generate the element-level representations. Then, we employ average pooling and mapping to aggregate the element-level representations into a set-level predicted latent code. As shown in Figure 4(c), operation 1 of our pipeline consists of a global feature extractor and a pre-trained DeepSDF model, while operation 2 consists of concatenation, average pooling, and mapping. This pipeline realizes a symmetric operation on unordered multi-sweep point clouds.", + "bbox": [ + 496, + 382, + 892, + 760 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.5. Model Training of MV-DeepSDF", + "text_level": 1, + "bbox": [ + 500, + 773, + 785, + 789 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We adopt a curriculum learning strategy for model training, which consists of two stages.", + "bbox": [ + 500, + 797, + 888, + 827 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Stage One. In stage one, we pre-train the DeepSDF decoder using watertight CAD models belonging to the car taxonomy of the ShapeNetV2 dataset [7]. The latent code $z$", + "bbox": [ + 498, + 854, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "8310", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "and parameters of the decoder $\\theta$ are jointly optimized as:", + "bbox": [ + 76, + 90, + 452, + 107 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\underset {\\theta , \\left\\{\\boldsymbol {z} _ {j} \\right\\} _ {j = 1} ^ {J}} {\\arg \\min } \\sum_ {j = 1} ^ {J} \\left(\\frac {1}{\\sigma^ {2}} \\left\\| \\boldsymbol {z} _ {j} \\right\\| _ {2} ^ {2} + \\sum_ {k = 1} ^ {K} \\mathcal {L} _ {1} \\left(f _ {\\theta} \\left(\\boldsymbol {z} _ {j}, \\boldsymbol {x} _ {k}\\right), s _ {k}\\right)\\right), \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 86, + 116, + 468, + 171 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $J$ represents the number of 3D shapes used for training and $K$ represents the number of points for each shape. During this stage, the decoder gains prior knowledge of vehicle shapes and once trained, the decoder remains fixed for the latent code generation step of our pipeline. Please refer to [31] for the details of the training at this step.", + "bbox": [ + 75, + 172, + 468, + 263 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Training Dataset Preparation for Stage Two. As shown in Eq. (6), ground truth latent codes, partial point clouds, and their corresponding latent codes are required for training the reconstruction network. However, real-world datasets, such as Waymo [36] and KITTI [15], do not contain ground truth shapes, so it is necessary to use a synthetic dataset [7] for generating the training data. To resolve this problem, we utilize the latent codes of the training shapes (e.g., the complete dense point cloud shown in Case 1 of Figure 3) as ground truth latent codes in the second stage of model training. As for the partial point clouds, the domain gap between training instances and in-the-wild instances directly determines the ability of our network to generalize to real-world datasets. To reduce the domain gap, we adopt PCGen [23] as our partial point cloud generation method. PCGen places a virtual LiDAR with real-world parameters (resolution and sampling pattern) around the vehicle and simulates the point cloud captured by the virtual LiDAR. This differs from the method used by DeepSDF [31], where a simulated depth camera is used as the virtual sensor instead of a LiDAR. A visual comparison of the real-world point cloud and simulated partial point clouds obtained using various methods is given in Figure 5. As shown in Figure 5, the partial point clouds of PCGen [23] are visually closer to the in-the-wild LiDAR sweeps of Waymo [36] and KITTI [15] than those of the virtual depth camera approach [31], which only raycasts evenly in the inclination and azimuth directions. Apart from this visual superiority, the advantages of generating partial point clouds with PCGen can also be observed through the improved generalization ability of our network. See experiments for further details.", + "bbox": [ + 75, + 281, + 472, + 750 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "When generating training data from ShapeNetV2 [7], we randomly sample one side of the vehicle to accurately reflect the real-world scan of a LiDAR on an ego-vehicle. In this way, we produce six partial point clouds for each vehicle. The virtual LiDAR pose for each partial point cloud is generated using a set of restrictions. These restrictions are set by considering the possible relative poses of an ego vehicle's LiDAR in the coordinate system of the other vehicle. In particular, $\\theta \\in [0^{\\circ}, 180^{\\circ}]$ or $\\theta \\in [-180^{\\circ}, 0^{\\circ}]$ , $r \\in [3, 15]$ , and $h \\in [0.8, 1.2]$ are used, where $\\theta$ represents the azimuth,", + "bbox": [ + 75, + 750, + 472, + 902 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/30f16c703f4b656e8cd24191236d3e2ffc85da5d9a635d276f612e95c5a0088c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 519, + 88, + 694, + 171 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/f4c86d858ccb74fdc389d952f3babf758bf13160c0d7362dad6fc71a34885111.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 700, + 89, + 875, + 171 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/2751cdca10a3d5ed7d1d8229aaab772a1213df621f962171f15d1a2be7fe2f44.jpg", + "image_caption": [ + "(c)", + "(d)", + "(e)", + "Figure 5. Visual comparison of in-the-wild partial point clouds and raycasted point clouds. (a) A partial point cloud from the Waymo tracking dataset [36]. (b) The raycasted point cloud generated by PCGen [23] using the LiDAR parameters of Waymo. (c) A partial point cloud from the KITTI tracking dataset [15]. (d) The raycasted point cloud generated by PCGen [23] using the LiDAR parameters of KITTI. (e) The raycasted point cloud obtained from the virtual depth camera approach used by DeepSDF [31]." + ], + "image_footnote": [], + "bbox": [ + 620, + 172, + 777, + 212 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "$r$ represents the distance between the LiDAR and the vehicle, and $h$ represents the height of the LiDAR to the ground. $\\theta, r,$ and $h$ describes the pose of the virtual LiDAR with respect to the frame of the other vehicle. Both $r$ and $h$ are expressed in the normalized space, where the size of the vehicle is normalized into the range $[-1, 1]$ . Finally, we generate a latent code for each partial point cloud using Eq. (1).", + "bbox": [ + 496, + 367, + 890, + 474 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Stage Two. In stage two, the network is trained to reconstruct 3D vehicles from multi-view partial point clouds and their corresponding latent codes. Consider the $c$ th vehicle instance. Let $P_{B,c}$ represent the set of partial point clouds, $Z_{B,c}$ represent the set of latent codes corresponding to the multi-view point clouds, and $z_{gt,c}$ represent the ground truth latent code acquired from stage one. Furthermore, let $g(\\cdot)$ represent the function of the implicit shape prediction network (refer to yellow and red blocks in Figure 2) and $\\alpha$ represent the parameters of the model. The training objective of stage two can be defined as:", + "bbox": [ + 496, + 493, + 892, + 660 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\underset {\\alpha} {\\arg \\min } \\sum_ {c = 1} ^ {C} \\mathcal {L} _ {2} \\left(g _ {\\alpha} \\left(\\boldsymbol {Z} _ {B, c}, \\boldsymbol {P} _ {B, c}\\right), \\boldsymbol {z} _ {g t, c}\\right), \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 557, + 672, + 890, + 712 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $C$ represents the number of instances employed for training and $\\mathcal{L}_2$ is the Mean Squared Error loss. The training details are presented in Sec. 4.1.", + "bbox": [ + 496, + 723, + 893, + 771 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 500, + 784, + 633, + 801 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this section, we present qualitative and quantitative results on two real-world autonomous driving datasets, namely Waymo [36] and KITTI [15]. The multi-sweep point clouds for Waymo are collected from 136 unique vehicle instances of Waymo Open Dataset's tracking data [36], while those for KITTI are extracted from 233 vehicle in", + "bbox": [ + 496, + 810, + 893, + 898 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "8311", + "bbox": [ + 480, + 944, + 514, + 957 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/468cb5d1e2e84e3ea597ed086246a8b1ec77fd0131991a6d33b9438fea42ba94.jpg", + "image_caption": [ + "Figure 6. Visual comparison with the state-of-the-art methods (DeepSDF [31], C-DeepSDF [11], MendNet [12], and AdaPoinTr [48]) on the Waymo [36] dataset. DeepSDF+MS and MendNet+MS indicate the models with multi-sweep input." + ], + "image_footnote": [], + "bbox": [ + 80, + 89, + 890, + 262 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "stances of KITTI's tracking dataset [15]. Due to page limitations, experiment details and some results (e.g., the results on the synthetic dataset ShapeNetV2 [7]) are discussed in the supplementary material.", + "bbox": [ + 75, + 321, + 468, + 383 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.1. Implementation Details", + "text_level": 1, + "bbox": [ + 76, + 390, + 294, + 406 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Architecture Details. Our global feature extractor, named shared PCN, is a variant of the PCN encoder [49]. The embedded shared MLP layers are identical to those of PointNet [32], which are implemented using 1D convolution layers. Moreover, since DeepSDF [31] normalizes the latent codes into the range $[-1, 1]$ , we add a tanh layer after the last shared MLP to normalize the global features into the same range as the latent codes. The decoder is identical to that of DeepSDF [31]. We report results based on an implementation with Python and PyTorch, but our approach also supports implementation with MindSpore [20].", + "bbox": [ + 75, + 414, + 470, + 580 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Training Details. In the first stage of training, we follow the same method as presented in DeepSDF [31] to train the decoder using watertight CAD models from the car taxonomy of ShapeNetV2 [7]. Once trained, the decoder is fixed and projects a 256-dimensional latent code to an SDF in 3D space. In the second stage, we train the model for 20 epochs using the Adam optimizer [21] with a learning rate of 1e-5. The batch size is set to 1, allowing the model to simultaneously see all 6 frames of the given instance at each iteration. Since both the output of the model and the supervision are 1D vectors, the loss computation is very fast. It only takes 10 minutes to train our network on a single NVIDIA GeForce RTX 2080 GPU during stage two. However, the DeepSDF decoder [31] used to prepare the training dataset for stage two through latent code generation is a more time-consuming process.", + "bbox": [ + 75, + 597, + 468, + 839 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.2. Evaluation Protocol", + "text_level": 1, + "bbox": [ + 76, + 847, + 266, + 861 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Metrics. Since an in-the-wild instance does not have a ground truth 3D shape, we follow [12] to evaluate the recon", + "bbox": [ + 75, + 869, + 468, + 900 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "struction results. In particular, the multiple LiDAR sweeps are stacked to construct the ground truth points set $\\pmb{X}$ . Moreover, we sample 30,000 points on the surface of each reconstructed mesh to generate the reconstruction points set $\\pmb{Y}$ . We employ Asymmetric Chamfer Distance (ACD) [12], which is the sum of the squared distance of each ground truth point to the nearest point in the reconstructed point set, to evaluate reconstruction results on real-world datasets:", + "bbox": [ + 496, + 321, + 890, + 441 + ], + "page_idx": 6 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {A C D} \\left(\\boldsymbol {X}, \\boldsymbol {Y}\\right) = \\sum_ {\\boldsymbol {x} \\in \\boldsymbol {X}} \\min _ {\\boldsymbol {y} \\in \\boldsymbol {Y}} \\| x - \\boldsymbol {y} \\| _ {2} ^ {2}. \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 571, + 448, + 890, + 479 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "For ACD, a smaller value is preferred. In addition, we compute the recall of the ground truth points from the reconstructed shape, which is defined as:", + "bbox": [ + 496, + 486, + 890, + 531 + ], + "page_idx": 6 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {R e c a l l} (\\boldsymbol {X}, \\boldsymbol {Y}) = \\frac {1}{| \\boldsymbol {X} |} \\sum_ {x \\in \\boldsymbol {X}} \\left[ \\min _ {y \\in \\boldsymbol {Y}} \\| x - y \\| _ {2} ^ {2} < = t \\right], \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 509, + 537, + 890, + 574 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "where the threshold $t$ is set as 0.1, following [12].", + "bbox": [ + 500, + 580, + 826, + 595 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Competitors. We compare our approach with four state-of-the-art methods, including three implicit modeling-based methods (DeepSDF [31], C-DeepSDF [11], and MendNet [12]) and AdaPoinTr [48], which is built upon PoinTr++ [47], the winner of Multi-View Partial Point Cloud Challenge 2021 on Completion and Registration [30]. Training data for DeepSDF and C-DeepSDF are generated following the original papers, while MendNet uses PCGen [23] to generate training data. The pipeline of AdaPoinTr [48] requires online generation of partial point clouds using the virtual depth camera approach and since it is not trivial to replace this process with PCGen, AdaPoinTr is trained using the default setup without PCGen. Note that with multi-sweep point clouds, competitors generate multiple reconstruction results (one for each partial point cloud), so we compare with the best single-shot reconstruction result, which is the mesh with the minimum ACD among the multiple single-shot reconstructed meshes. Furthermore, we report the results of DeepSDF and MendNet with multi-sweep", + "bbox": [ + 496, + 613, + 892, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "8312", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/cf73b2e96ff7708ab265aa1ac7cb23fba8a3f707607d85073d9d2251289df6d2.jpg", + "table_caption": [], + "table_footnote": [ + "Table 1. Comparison with the state-of-the-art methods on Waymo. ACD $\\downarrow$ is multiplied by $10^{3}$ . Recall $\\uparrow$ is presented as a percentage. *AdaPoinTr is trained with the default setup without PCGen on the large-scale ShapeNet-55 [47] following the original paper [48], and then fine-tuned on the car taxonomy of ShapeNetV2 in our experiments. Other methods are only trained with the car taxonomy of ShapeNetV2." + ], + "table_body": "
Method \\ MetricACDmean ↓ACDmedian ↓Recall ↑
DeepSDF [31]6.265.8193.51
DeepSDF+MS5.125.0995.57
C-DeepSDF [11]6.215.6493.98
MendNet [12]4.924.7995.39
MendNet+MS4.854.7795.76
AdaPoinTr*[48]4.794.7495.95
Ours-VDC4.764.5596.05
Ours3.362.2696.84
", + "bbox": [ + 83, + 88, + 462, + 217 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "inputs (denoted as DeepSDF+MS and MendNet+MS), in which we stack the partial point clouds of multi-sweeps into a single point cloud and perform single-shot-based reconstruction on this stacked point cloud. For our approach, in addition to the default setup which generates the training dataset using PCGen (denoted as Ours), we also adapt our approach to use training data generated by the virtual depth camera approach [31] (denoted as Ours-VDC).", + "bbox": [ + 76, + 339, + 467, + 459 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.3. Results on Waymo", + "text_level": 1, + "bbox": [ + 76, + 469, + 254, + 484 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "The qualitative and quantitative comparisons of our approach with the state-of-the-art methods are presented in Figure 6 and Table 1, respectively. Overall, our approach achieves the best reconstruction results both qualitatively and quantitatively. Specifically, from Figure 6 and Table 1, we can see that DeepSDF [31] and C-DeepSDF [11] are sensitive to noise, resulting in low fidelity. MendNet [12] generates more stable results than DeepSDF and C-DeepSDF, but its reconstruction meshes contain some irregular holes on the surface (see sixth column of Figure 6). Although AdaPoinTr [48] outputs point clouds with good fidelity, it expresses the shape with a limited resolution and thus fails to describe continuous local details (see seventh column of Figure 6).", + "bbox": [ + 76, + 492, + 467, + 703 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Compared with vanilla DeepSDF and MendNet, DeepSDF+MS and MendNet+MS yield messier surfaces/structures (see fourth and eighth columns of Figure 6), despite their better metric scores. This shows that even though transforming all partial point clouds into a single frame does benefit information aggregation, it also accumulates noise and annotation errors in the process. Hence, due to noise in real-world data, it is not practical to geometrically stack multi-sweep point clouds and directly perform single-shot-based reconstruction. In comparison, our approach generates smooth watertight shapes (see last two columns of Figure 6) with high fidelity (see Table 1). Furthermore, Ours outperforms Ours-VDC, which indicates", + "bbox": [ + 76, + 704, + 467, + 898 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/83965e8d867b2d2664ba18ba8b2f3149a6b4eed1b7b0e37cf00a56a3ff686555.jpg", + "table_caption": [], + "table_footnote": [ + "Table 2. Comparison with the state-of-the-art methods on KITTI. ACD $\\downarrow$ is multiplied by ${10}^{3}$ . Recall $\\uparrow$ is presented as a percentage." + ], + "table_body": "
Method \\ MetricACDmean ↓ACDmedian ↓Recall ↑
DeepSDF [31]6.816.1780.65
DeepSDF+MS6.115.8382.73
C-DeepSDF [11]6.735.9980.77
MendNet [12]5.945.6483.84
MendNet+MS5.835.6184.26
AdaPoinTr [48]5.895.6784.20
Ours-VDC5.755.2484.39
Ours4.273.0185.88
", + "bbox": [ + 506, + 89, + 885, + 217 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "that using PCGen to prepare training partial point clouds (refer to Figure 5) reduces the domain gap between training and in-the-wild instances.", + "bbox": [ + 498, + 271, + 890, + 315 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.4. Results on KITTI", + "text_level": 1, + "bbox": [ + 500, + 327, + 671, + 343 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "The qualitative and quantitative comparisons of our approach against the state-of-the-art methods are presented in Figure 7 and Table 2, respectively. From these results, we can also observe the superior performance of our approach over the state-of-the-art competitors. Specifically, qualitatively, as shown in Figure 7, our approaches (Ours and Ours-VDC) are more robust to noise when compared to DeepSDF [31], DeepSDF+MS, and C-DeepSDF [11] and generate smoother, watertight surfaces compared to MendNet [12], AdaPoinTr [48], and MendNet+MS. Quantitatively, as shown in Table 2, Ours yields the best ACD and Recall results, while Ours-VDC performs the second best.", + "bbox": [ + 496, + 351, + 890, + 532 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.5. Ablation Study", + "text_level": 1, + "bbox": [ + 500, + 544, + 653, + 559 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "To verify the effectiveness of the main components of our approach, we carry out a series of experiments on Waymo [36] as shown in Table 3. The first row of Table 3 refers to the baseline model of our approach, which is a shared PCN encoder (Enc.) (yellow block in Figure 2) followed by an average pooling layer (Avg.). This architecture is similar to that of MendNet [12], which adds two stacked PointNet encoders [32] to the DeepSDF decoder. In the second row, we directly use bitwise multiplication to merge the global features $(\\mathrm{B} \\times 256$ , instead of $\\mathrm{B} \\times 1024)$ and the latent codes $(\\mathrm{B} \\times 256)$ . However, this results in obvious performance degradation, which shows that directly merging the global features and latent codes obtained from multi-sweep information does not bring improvement to our baseline model. In comparison, in the third row, we add our proposed components, namely the input of latent codes (Dep.), concatenation (Con.), and mapping (Map.), to the baseline model, but with max pooling. This brings significant performance improvement compared to the first and second rows. Then, in the last row, we further replace max pooling with average pooling, which includes all proposed components of this work. This yields the best results.", + "bbox": [ + 496, + 568, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "8313", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/18f87ca6b80bdaed4bb7c8ec381d474b6a20ba3ca66c6d70847942fa6993c4db.jpg", + "image_caption": [ + "Figure 7. Visual comparison with the state-of-the-art methods (DeepSDF [31], C-DeepSDF [11], MendNet [12], and AdaPoinTr [48]) on the KITTI [15] dataset. DeepSDF+MS and MendNet+MS indicate the models with multi-sweep input." + ], + "image_footnote": [], + "bbox": [ + 83, + 89, + 890, + 262 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/dc1b8de9766d03ee2e3024b190de68a4a14c41b1cd1c8d0ef546e96cc9391c10.jpg", + "table_caption": [], + "table_footnote": [ + "Table 3. The ablation study of the proposed framework. Refer to Figure 4(b) to see the definitions of operations 1 and 2. Enc.: the shared PCN encoder; Dep.: latent code generation through DeepSDF as input; Mer.: the operation to merge global features and latent codes; Map.: the mapping conducted by the fully-connected layer; Con.: the concatenation; Mul.: the bitwise multiplication; Avg.: average pooling; Max.: max pooling. ACD $\\downarrow$ is multiplied by $10^{3}$ . Recall $\\uparrow$ is presented as a percentage." + ], + "table_body": "
Operation 1Operation 2Metric
Enc.Dep.Mer.PoolMap.ACD ↓Recall ↑
✓Avg.4.8995.50
✓✓Mul.Avg.7.3384.93
✓✓Con.Max.✓4.3596.61
✓✓Con.Avg.✓3.3696.84
", + "bbox": [ + 84, + 318, + 460, + 407 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "4.6. Extension to Other Taxonomies", + "text_level": 1, + "bbox": [ + 76, + 544, + 354, + 558 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "It is straightforward to extend the proposed shape completion framework to other taxonomies. Suppose that we want to extend MV-DeepSDF to perform shape completion on sofas. First, a new DeepSDF decoder [31] needs to be pre-trained using watertight CAD models from the sofa taxonomy of ShapeNetV2 [7] or another synthetic dataset. Then, PCGen [23] or another sampling technique (e.g., the approaches proposed in [31, 47]) can be used to generate partial point clouds for each sofa instance. These partial point clouds are then passed into the pre-trained DeepSDF decoder [31] to produce their corresponding latent codes. Finally, the partial point clouds and latent codes can be used together to train MV-DeepSDF. Following the pipeline above, we evaluate on indoor sofas of ShapeNetV2 and outdoor cyclists of Waymo and show that our method is versatile and extendible to other taxonomies (see Figure 8).", + "bbox": [ + 75, + 566, + 468, + 808 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "While existing datasets, such as ScanNet [8] and Semantic3D [18], provide real-world point cloud data for many taxonomies, the availability of tracking data for multisweep scans is still fairly limited to the autonomous driving industry. Hence, it is necessary to first obtain the corresponding multi-sweep tracking labels for the desired class", + "bbox": [ + 75, + 810, + 470, + 901 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/c4cb8880ef53068dcf8ed84513b605e3aac76208b6df9007a5488ed48d7d2f16.jpg", + "image_caption": [ + "DeepSDF" + ], + "image_footnote": [], + "bbox": [ + 526, + 335, + 607, + 367 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/a875898f1b839db6763c802e3a3a8a78f181d0a0411b55198939f8d323fdada3.jpg", + "image_caption": [ + "Ours" + ], + "image_footnote": [], + "bbox": [ + 622, + 338, + 704, + 369 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/7e5ebe97fcaccc30098413a0ea2f79925b9794c31ed7eb0f6025987cd27b1331.jpg", + "image_caption": [ + "DeepSDF", + "Figure 8. Visual comparison of DeepSDF and MV-DeepSDF on the indoor sofa of ShapeNetV2 and the outdoor cyclist of Waymo." + ], + "image_footnote": [], + "bbox": [ + 723, + 321, + 784, + 375 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/08de1cbce990fce5abfa5b29c3e4924de05892e5dee43379958883d6205407c4.jpg", + "image_caption": [ + "Ours" + ], + "image_footnote": [], + "bbox": [ + 810, + 321, + 857, + 375 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "when choosing to adopt MV-DeepSDF on a new taxonomy.", + "bbox": [ + 500, + 446, + 888, + 463 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 474, + 617, + 489 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this work, we propose a new MV-DeepSDF framework to facilitate implicit modeling with multi-sweep point clouds for autonomous driving. The main idea is to abstract 3D vehicle reconstruction from multi-sweeps into an element-to-set feature extraction problem. Namely, we consider the multi-sweeps of a vehicle as elements composing a set and infer the set feature, which is an optimal estimation of the 3D shape described in the abstract implicit space. In particular, we present a theoretical analysis of multi-sweep consistency and complementarity in the latent feature space. Guided by this analysis, we design a new architecture to optimally estimate the Signed Distance Function shape of a vehicle from its in-the-wild multi-sweep point clouds. Qualitative and quantitative evaluations on both real-world and synthetic datasets show the superiority of our approach over the state-of-the-art methods.", + "bbox": [ + 496, + 500, + 890, + 739 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Limitation. Despite promising results, our approach still relies on a synthetic 3D dataset to gain prior knowledge of 3D shapes for reconstruction. Exploring reconstruction by learning directly from real data is worthy of further study.", + "bbox": [ + 496, + 741, + 890, + 801 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgments", + "text_level": 1, + "bbox": [ + 500, + 815, + 658, + 830 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "The authors gratefully acknowledge the support of MindSpore, CANN, and Ascend AI Processor. The authors would also like to thank Andrew Yang and Hunter Schofield for their assistance.", + "bbox": [ + 496, + 839, + 890, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "8314", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Dejan Azinović, Ricardo Martin-Brualla, Dan B Goldman, Matthias Nießner, and Justus Thies. Neural rgb-d surface reconstruction. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6290-6301, 2022.", + "[2] Heli Ben-Hamu, Haggai Maron, Itay Kezurer, Gal Avineri, and Yaron Lipman. Multi-chart generative surface modeling. ACM Transactions on Graphics, 37(6):1-15, 2018.", + "[3] Paul J Besl and Neil D McKay. Method for registration of 3-d shapes. In Sensor fusion IV: control paradigms and data structures, volume 1611, pages 586-606. Spie, 1992.", + "[4] Hongrui Cai, Wanquan Feng, Xuetao Feng, Yan Wang, and Juyong Zhang. Neural surface reconstruction of dynamic scenes with monocular rgb-d camera. In Proc. of Conference on Neural Information Processing Systems, 2022.", + "[5] Yingjie Cai, Kwan-Yee Lin, Chao Zhang, Qiang Wang, Xiaogang Wang, and Hongsheng Li. Learning a structured latent space for unsupervised point cloud completion. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5543-5553, 2022.", + "[6] Rohan Chabra, Jan E Lenssen, Eddy Ilg, Tanner Schmidt, Julian Straub, Steven Lovegrove, and Richard Newcombe. Deep local shapes: Learning local sdf priors for detailed 3d reconstruction. In Proc. of European Conference on Computer Vision, pages 608-625. Springer, 2020.", + "[7] Angel X Chang, Thomas Funkhouser, Leonidas Guibas, Pat Hanrahan, Qixing Huang, Zimo Li, Silvio Savarese, Manolis Savva, Shuran Song, Hao Su, et al. Shapenet: An information-rich 3d model repository. arXiv preprint arXiv:1512.03012, 2015.", + "[8] Angela Dai, Angel X Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 5828-5839, 2017.", + "[9] Angela Dai, Christian Diller, and Matthias Nießner. Sg-nn: Sparse generative neural networks for self-supervised scene completion of rgb-d scans. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 849–858, 2020.", + "[10] Angela Dai, Charles Ruizhongtai Qi, and Matthias Nießner. Shape completion using 3d-encoder-predictor cnns and shape synthesis. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 5868-5877, 2017.", + "[11] Yueqi Duan, Haidong Zhu, He Wang, Li Yi, Ram Nevata, and Leonidas J Guibas. Curriculum deepsdf. In Proc. of European Conference on Computer Vision, pages 51-67. Springer, 2020.", + "[12] Shivam Duggal, Zihao Wang, Wei-Chiu Ma, Sivabalan Manivasagam, Justin Liang, Shenlong Wang, and Raquel Urtasun. Mending neural implicit modeling for 3d vehicle reconstruction in the wild. In Proc. of IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1900-1909, 2022." + ], + "bbox": [ + 78, + 114, + 467, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[13] Francis Engelmann, Jörg Stuckler, and Bastian Leibe. Samp: shape and motion priors for 4d vehicle reconstruction. In Proc. of IEEE Winter Conference on Applications of Computer Vision, pages 400-408. IEEE, 2017.", + "[14] Qiaojun Feng, Yue Meng, Mo Shan, and Nikolay Atanasov. Localization and mapping using instance-specific mesh models. In Proc. of IEEE/RSJ International Conference on Intelligent Robots and Systems, pages 4985-4991. IEEE, 2019.", + "[15] Andreas Geiger, Philip Lenz, Christoph Stiller, and Raquel Urtasun. Vision meets robotics: The kitti dataset. The International Journal of Robotics Research, 32(11):1231-1237, 2013.", + "[16] Thibault Groueix, Matthew Fisher, Vladimir G Kim, Bryan C Russell, and Mathieu Aubry. A papier-mâché approach to learning 3d surface generation. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 216-224, 2018.", + "[17] Jiayuan Gu, Wei-Chiu Ma, Sivabalan Manivasagam, Wenyuan Zeng, Zihao Wang, Yuwen Xiong, Hao Su, and Raquel Urtasun. Weakly-supervised 3d shape completion in the wild. In Proc. of European Conference on Computer Vision, pages 283-299. Springer, 2020.", + "[18] Timo Hackel, Nikolay Savinov, Lubor Ladicky, Jan D Wegner, Konrad Schindler, and Marc Pollefeys. Semantic3d. net: A new large-scale point cloud classification benchmark. arXiv preprint arXiv:1704.03847, 2017.", + "[19] Tao Hu, Zhizhong Han, Abhinav Shrivastava, and Matthias Zwicker. Render4completion: Synthesizing multi-view depth maps for 3d shape completion. In Proc. of the IEEE/CVF International Conference on Computer Vision Workshops, pages 0–0, 2019.", + "[20] Huawei. Mindspace. https://www.mindspore.cn/, 2020.", + "[21] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. In Proc. of the International Conference on Learning Representations (Poster), 2015.", + "[22] Chen Kong, Chen-Hsuan Lin, and Simon Lucey. Using locally corresponding cad models for dense 3d reconstructions from a single image. In Proc. the IEEE conference on computer vision and pattern recognition, pages 4857-4865, 2017.", + "[23] Chenqi Li, Yuan Ren, and Bingbing Liu. Pcgen: Point cloud generator for lidar simulation. In Proc. of International Conference on Robotics and Automation, 2023.", + "[24] William E Lorensen and Harvey E Cline. Marching cubes: A high resolution 3d surface construction algorithm. ACM siggraph computer graphics, 21(4):163-169, 1987.", + "[25] Shirui Luo, Changqing Zhang, Wei Zhang, and Xiaochun Cao. Consistent and specific multi-view subspace clustering. In Proc. of the AAAI conference on artificial intelligence, volume 32, 2018.", + "[26] Xiaoxu Meng, Weikai Chen, and Bo Yang. Neat: Learning neural implicit surfaces with arbitrary topologies from multi-view images. Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, June 2023.", + "[27] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks:" + ], + "bbox": [ + 501, + 92, + 890, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "8315", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Learning 3d reconstruction in function space. In Proc. of IEEE Conf. on Computer Vision and Pattern Recognition, 2019.", + "[28] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021.", + "[29] Richard A Newcombe, Shahram Izadi, Otmar Hilliges, David Molyneaux, David Kim, Andrew J Davison, Pushmeet Kohi, Jamie Shotton, Steve Hodges, and Andrew Fitzgibbon. Kinectfusion: Real-time dense surface mapping and tracking. In Proc. IEEE international symposium on mixed and augmented reality, pages 127-136. Ieee, 2011.", + "[30] Liang Pan, Tong Wu, Zhongang Cai, Ziwei Liu, Xumin Yu, Yongming Rao, Jiwen Lu, Jie Zhou, Mingye Xu, Xiaoyuan Luo, et al. Multi-view partial (mvp) point cloud challenge 2021 on completion and registration: Methods and results. arXiv preprint arXiv:2112.12053, 2021.", + "[31] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. Deepsdf: Learning continuous signed distance functions for shape representation. In Proc. of the IEEE/CVF conference on computer vision and pattern recognition, pages 165-174, 2019.", + "[32] Charles R Qi, Hao Su, Kaichun Mo, and Leonidas J Guibas. Pointnet: Deep learning on point sets for 3d classification and segmentation. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 652-660, 2017.", + "[33] Charles Ruizhongtai Qi, Li Yi, Hao Su, and Leonidas J Guibas. Pointnet++: Deep hierarchical feature learning on point sets in a metric space. Advances in neural information processing systems, 30, 2017.", + "[34] Radu Bogdan Rusu, Nico Blodow, and Michael Beetz. Fast point feature histograms (fpfh) for 3d registration. In Proc. of IEEE international conference on robotics and automation, pages 3212-3217. IEEE, 2009.", + "[35] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5459-5469, 2022.", + "[36] Pei Sun, Henrik Kretzschmar, Xerxes Dotiwalla, Aurelien Chouard, Vijaysai Patnaik, Paul Tsui, James Guo, Yin Zhou, Yuning Chai, Benjamin Caine, et al. Scalability in perception for autonomous driving: Waymo open dataset. In Proc. of the IEEE/CVF conference on computer vision and pattern recognition, pages 2446-2454, 2020.", + "[37] Shubham Tulsiani, Alexei A Efros, and Jitendra Malik. Multi-view consistency as supervisory signal for learning shape and pose prediction. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 2897-2905, 2018.", + "[38] Nitika Verma, Edmond Boyer, and Jakob Verbeek. Feastnet: Feature-steered graph convolutions for 3d shape analysis. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 2598-2606, 2018.", + "[39] Dan Wang, Xinrui Cui, Xun Chen, Zhengxia Zou, Tianyang Shi, Septimiu Salcudean, Z Jane Wang, and Rabab Ward." + ], + "bbox": [ + 78, + 90, + 470, + 900 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Multi-view 3d reconstruction with transformers. In Proc. of the IEEE/CVF International Conference on Computer Vision, pages 5722-5731, 2021.", + "[40] Nanyang Wang, Yinda Zhang, Zhuwen Li, Yanwei Fu, Wei Liu, and Yu-Gang Jiang. Pixel2mesh: Generating 3d mesh models from single rgb images. In Proc. of the European conference on computer vision, pages 52-67, 2018.", + "[41] Peng Wang, Lingjie Liu, Yuan Liu, Christian Theobalt, Taku Komura, and Wenping Wang. Neus: Learning neural implicit surfaces by volume rendering for multi-view reconstruction. arXiv preprint arXiv:2106.10689, 2021.", + "[42] Xiaogang Wang, Marcelo H Ang, and Gim Hee Lee. Voxel-based network for shape completion by leveraging edge generation. In Proc. of the IEEE/CVF international conference on computer vision, pages 13189-13198, 2021.", + "[43] Haozhe Xie, Hongxun Yao, Shangchen Zhou, Jiageng Mao, Shengping Zhang, and Wenxiu Sun. Grnet: Gridding residual network for dense point cloud completion. In Proc. of the European conference on computer vision, pages 365-381. Springer, 2020.", + "[44] Qiangeng Xu, Zexiang Xu, Julien Philip, Sai Bi, Zhixin Shu, Kalyan Sunkavalli, and Ulrich Neumann. Point-nerf: Point-based neural radiance fields. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5438-5448, 2022.", + "[45] Jianglong Ye, Yuntao Chen, Naiyan Wang, and Xiaolong Wang. Gifs: Neural implicit function for general shape representation. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12829-12839, 2022.", + "[46] Jianglong Ye, Yuntao Chen, Naiyan Wang, and Xiaolong Wang. Online adaptation for implicit object tracking and shape reconstruction in the wild. IEEE Robotics and Automation Letters, 7(4):8909-8916, 2022.", + "[47] Xumin Yu, Yongming Rao, Ziyi Wang, Zuyan Liu, Jiwen Lu, and Jie Zhou. Pointr: Diverse point cloud completion with geometry-aware transformers. In Proc. of the IEEE/CVF international conference on computer vision, pages 12498-12507, 2021.", + "[48] Xumin Yu, Yongming Rao, Ziyi Wang, Jiwen Lu, and Jie Zhou. Adapointr: Diverse point cloud completion with adaptive geometry-aware transformers. arXiv preprint arXiv:2301.04545, 2023.", + "[49] Wentao Yuan, Tejas Khot, David Held, Christoph Mertz, and Martial Hebert. Pcn: Point completion network. In Proc. of International Conference on 3D Vision, pages 728-737, 2018.", + "[50] Changqing Zhang, Zongbo Han, Huazhu Fu, Joey Tianyi Zhou, Qinghua Hu, et al. Cpm-nets: Cross partial multiview networks. Advances in Neural Information Processing Systems, 32, 2019." + ], + "bbox": [ + 501, + 92, + 890, + 811 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "8316", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/0f77204f-207d-45fd-9794-f340dac7f292_model.json b/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/0f77204f-207d-45fd-9794-f340dac7f292_model.json new file mode 100644 index 0000000000000000000000000000000000000000..fe3a079da968b2a4eacc5d116f76c6af51faa6b2 --- /dev/null +++ b/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/0f77204f-207d-45fd-9794-f340dac7f292_model.json @@ -0,0 +1,2301 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.157, + 0.131, + 0.819, + 0.177 + ], + "angle": 0, + "content": "MV-DeepSDF: Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving" + }, + { + "type": "text", + "bbox": [ + 0.133, + 0.203, + 0.838, + 0.24 + ], + "angle": 0, + "content": "Yibo Liu\\(^{1,2}\\), Kelly Zhu\\(^{1,3}\\), Guile Wu\\(^{1}\\), Yuan Ren\\(^{1}\\), Bingbing Liu\\(^{1}\\), Yang Liu\\(^{1}\\), Jinjun Shan\\(^{2}\\) \n\\(^{1}\\)Huawei Noah's Ark Lab, \\(^{2}\\)York University, \\(^{3}\\)University of Toronto" + }, + { + "type": "text", + "bbox": [ + 0.232, + 0.242, + 0.738, + 0.275 + ], + "angle": 0, + "content": "{yorklyb, jjshan}@yorku.ca, kellyk.zhu@mail.utoronto.ca \n{guile.wu, yuan.ren3, liu.bingbing, yang.liu9}@huawei.com" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.309, + 0.314, + 0.327 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.343, + 0.474, + 0.751 + ], + "angle": 0, + "content": "Reconstructing 3D vehicles from noisy and sparse partial point clouds is of great significance to autonomous driving. Most existing 3D reconstruction methods cannot be directly applied to this problem because they are elaborately designed to deal with dense inputs with trivial noise. In this work, we propose a novel framework, dubbed MV-DeepSDF, which estimates the optimal Signed Distance Function (SDF) shape representation from multisweep point clouds to reconstruct vehicles in the wild. Although there have been some SDF-based implicit modeling methods, they only focus on single-view-based reconstruction, resulting in low fidelity. In contrast, we first analyze multi-sweep consistency and complementarity in the latent feature space and propose to transform the implicit space shape estimation problem into an element-to-set feature extraction problem. Then, we devise a new architecture to extract individual element-level representations and aggregate them to generate a set-level predicted latent code. This set-level latent code is an expression of the optimal 3D shape in the implicit space, and can be subsequently decoded to a continuous SDF of the vehicle. In this way, our approach learns consistent and complementary information among multi-sweeps for 3D vehicle reconstruction. We conduct thorough experiments on two real-world autonomous driving datasets (Waymo and KITTI) to demonstrate the superiority of our approach over state-of-the-art alternative methods both qualitatively and quantitatively." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.784, + 0.21, + 0.799 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.471, + 0.902 + ], + "angle": 0, + "content": "3D vehicle reconstruction from sparse and partial point clouds is a fundamental need in the autonomous driving industry [12, 17]. It aims to infer the 3D structure of vehicles at arbitrary resolutions in the wild, which is of great significance to many downstream tasks in autonomous driving. Despite the many 3D reconstruction methods" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.309, + 0.895, + 0.416 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.421, + 0.895, + 0.506 + ], + "angle": 0, + "content": "Figure 1. An illustration of the motivation of the proposed approach. Our approach takes multi-sweep point clouds as input and simplifies 3D vehicle reconstruction from multi-sweeps into an element-to-set feature extraction problem. In this way, we infer an optimal estimation of the 3D shape described in the abstract implicit space for 3D vehicle reconstruction in autonomous driving." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.534, + 0.895, + 0.595 + ], + "angle": 0, + "content": "[28, 35, 26, 39, 41, 1, 19, 4], most of them focus on image-based inputs [28, 35, 26, 39, 41], dense point cloud inputs [19, 31, 11], or their combination [1, 4, 9] and thus, cannot be directly applied to this problem." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.597, + 0.896, + 0.793 + ], + "angle": 0, + "content": "Recently, [12] has shown promising performance in applying implicit modeling to tackle this problem. Contrary to explicit modeling methods [32, 33, 47, 49, 43, 42, 10, 2, 38] that directly represent 3D object shape structure with points, voxels, or meshes, implicit modeling maps the 3D shape to a low-dimensional latent space and learns the projection from the latent space to a continuous function that describes the 3D shape. This presents two significant advantages: 1) the 3D shape can be stored as a low-dimensional memory-saving latent code [31, 11, 12, 6]; 2) the trained network outputs a continuous function in the 3D space which supports mesh extraction at any resolution [31]. To this end, we also choose to employ implicit modeling in our approach." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.895, + 0.903 + ], + "angle": 0, + "content": "However, previous point cloud-based implicit modeling methods [31, 11, 12] mainly focus on recovering 3D shapes from a single-view partial point cloud and fail to leverage the multi-sweep information of vehicles. As a result, when noise or annotation errors exist in an individual sweep, single-view methods usually produce low fidelity results. In real-world datasets (e.g., [36, 15]), multi-sweep" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8306" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.08, + 0.088, + 0.895, + 0.314 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.318, + 0.895, + 0.404 + ], + "angle": 0, + "content": "Figure 2. The framework of the proposed MV-DeepSDF. Farthest Point Sampling (FPS) [33] is applied to the raw point clouds for preprocessing and DeepSDF [31] is employed to generate a latent code for each observation. We then extract global features from the standardized point clouds (refer to yellow block) and concatenate the global features with the latent codes as element-level representations. Next, the element-level representations are transformed into a set-level predicted latent code (refer to red block). Finally, we employ a pre-trained DeepSDF decoder [31] to project the predicted latent code to the SDF of the vehicle in 3D space and recover the 3D mesh. Note that the decoder used in the final step (refer to white trapezoid) is identical to that of DeepSDF (refer to green block)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.427, + 0.47, + 0.517 + ], + "angle": 0, + "content": "point clouds are usually available and contain richer shape information because of the various viewing angles offered by multiple observations [17]. Although there are some existing 3D reconstruction methods from multi-view point clouds [17, 19, 3, 34], implicit modeling with multi-sweep point clouds remains an unsolved problem." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.518, + 0.471, + 0.879 + ], + "angle": 0, + "content": "In this work, we propose a novel framework, dubbed MV-DeepSDF, to exploit multi-sweep point clouds and implicitly generate high-fidelity 3D reconstructions of vehicles for autonomous driving. An illustration of the motivation for our proposed approach is depicted in Figure 1. Specifically, to shed light on the importance of exploring multi-sweep point clouds for 3D vehicle reconstruction, we first analyze multi-sweep consistency and complementarity in the latent feature space. We then propose to consider the problem of shape estimation in the implicit space as an element-to-set feature extraction problem, where a set represents a collection of multi-sweeps and an element represents a sparse and partial point cloud. Next, we devise a new architecture to simultaneously extract a global feature and latent code for each element in the multi-sweep and concatenate them as element-level representations. These element-level representations are then transformed into a set-level predicted latent code with the aid of average pooling and mapping. This set-level latent code is an optimal estimation of the 3D shape described in the abstract implicit space, which we subsequently decode to a continuous SDF of the vehicle with a pre-trained DeepSDF decoder [31] and recover the 3D mesh from the SDF. The contributions of this work are threefold:" + }, + { + "type": "text", + "bbox": [ + 0.094, + 0.886, + 0.471, + 0.902 + ], + "angle": 0, + "content": "We analyze multi-sweep consistency and complement" + }, + { + "type": "text", + "bbox": [ + 0.531, + 0.427, + 0.892, + 0.518 + ], + "angle": 0, + "content": "tarity in the latent feature space and transform the problem of shape estimation in the implicit space into an element-to-set feature extraction problem. This simplifies 3D vehicle reconstruction from multi-sweep point clouds into an optimal estimation of the 3D shape described in the abstract implicit space." + }, + { + "type": "text", + "bbox": [ + 0.516, + 0.532, + 0.892, + 0.608 + ], + "angle": 0, + "content": "- We propose a novel MV-DeepSDF framework (see Figure 2) for implicit modeling with multi-sweep point clouds. A new architecture is constructed to extract the element-level representations and generate the set-level predicted latent code." + }, + { + "type": "text", + "bbox": [ + 0.516, + 0.622, + 0.894, + 0.683 + ], + "angle": 0, + "content": "- We qualitatively and quantitatively demonstrate the superior performance of our approach over the state-of-the-art alternative methods through extensive experiments on real-world datasets [36, 15]." + }, + { + "type": "list", + "bbox": [ + 0.516, + 0.532, + 0.894, + 0.683 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.7, + 0.642, + 0.715 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.726, + 0.874, + 0.742 + ], + "angle": 0, + "content": "2.1. Explicit Modeling-Based 3D Reconstruction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Conventional 3D explicit modeling can be classified into three categories, namely point-based [32, 33, 47, 49, 43], voxel-based [42, 10], and mesh-based [2, 38]. Point-based methods, such as Point Completion Network (PCN) [49], GRNet [43], and PoinTr [47], output a point cloud with limited resolution since the number of points is fixed and not suitable for generating watertight surfaces due to lack of topology description. Voxel-based methods [42, 10] describe volumes by subdividing the space into a 3D grid, but they are memory and compute intensive, leading to slow" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8307" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.228 + ], + "angle": 0, + "content": "training and low resolution representations [31]. Mesh-based methods only generate meshes with simple topologies [40] given by a fixed reference template from the same object class and cannot guarantee watertight surfaces [22, 16]. In contrast, we propose implicit modeling with multi-sweep point clouds in a novel MV-DeepSDF framework, which estimates the optimal SDF shape representation for reconstructing 3D structures of vehicles in autonomous driving." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.239, + 0.453, + 0.256 + ], + "angle": 0, + "content": "2.2. Implicit Modeling-Based 3D Reconstruction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.262, + 0.473, + 0.61 + ], + "angle": 0, + "content": "Implicit modeling [27, 31, 11, 12] uses function-based decision boundaries to implicitly define surfaces for 3D representations. DeepSDF [31] is a classical approach to implicit modeling. It estimates the Signed Distance Function (SDF) of an object from a partial point cloud, where the SDF specifies whether a querying position is inside or outside the surface of the object and the distance of the querying position from the surface. There have been some improved versions [11, 12, 6, 45] of DeepSDF, but these methods only focus on 3D reconstruction from a single-view point cloud and thus, generally produce low fidelity results when noise or annotation errors exist in an individual sweep. In contrast, we propose a novel framework for implicit modeling with multi-sweep point clouds. We analyze multi-sweep consistency and complementarity in the latent feature space and propose to resolve this problem by an optimal estimation of the 3D shape described in the abstract implicit space. Moreover, other implicit modeling-based methods, such as Neural Radiance Fields (NeRF) [28], Point-NeRF [44], Direct Voxel Grid Optimization [35], NeuS [41], NEAT [26], and [1, 4, 9] exist, but they all require image input and cannot deal with only LiDAR data." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.621, + 0.35, + 0.637 + ], + "angle": 0, + "content": "2.3. Multi-View 3D Reconstruction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.644, + 0.473, + 0.903 + ], + "angle": 0, + "content": "3D reconstruction from multi-view point clouds can be categorized into conventional approaches [3, 34, 29] and deep learning-based approaches [17, 19, 5]. Conventional geometric approaches, such as Iterative Closest Point (ICP), TSDF [29], and [3, 34], only leverage multi-view observations geometrically, so the resulting completion is merely an aligned stack of partial point clouds and cannot produce watertight shapes unless the sensor fully loops around the object. In deep learning-based approaches, [17] proposes a weakly-supervised framework to directly learn 3D shape completion from multi-view LiDAR sweeps, but its reconstruction result is not watertight. [19] presents a shape completion framework using a multi-view depth map-based shape representation approach, while [5] designs a network to use multiple partial point clouds encoded into the latent space to estimate the optimal shape of the object. However, the output of these networks [19, 5] are point-based repre" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.895, + 0.304 + ], + "angle": 0, + "content": "sentations and in contrast with continuous field functions such as SDFs [31], lack continuity in 3D space. Moreover, some methods, such as [13, 14, 46], exist for reconstructing vehicle shapes from multiple observations, but [13] relies on stereo images and motion priors to regularize the shape estimation of vehicles, [14] requires multi-view camera images to build semantic maps which contain 3D vehicle shapes, and [46] requires inputs to follow a time sequence to track and reconstruct 3D objects. In contrast, our approach simplifies 3D vehicle reconstruction from multisweep point clouds into an optimal estimation of the 3D shape described in the abstract implicit space, which supports mesh extraction at any resolution and can deal with noise and annotation errors that exist in an individual sweep." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.317, + 0.637, + 0.334 + ], + "angle": 0, + "content": "3. Methodology" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.341, + 0.642, + 0.356 + ], + "angle": 0, + "content": "3.1. Preliminaries" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.364, + 0.895, + 0.622 + ], + "angle": 0, + "content": "In this section, we introduce preliminaries regarding DeepSDF [31] since our approach utilizes its framework for extracting the latent code and decoding the continuous SDF for 3D mesh generation. Formally, when adopting the DeepSDF decoder into the shape completion task, points of partial point clouds are taken as given surface points and the SDF value is defined as the distance from the querying point to the surface of the object. Interior and exterior querying points are sampled along the normals of the surface points and the SDF value is computed for each querying point. Suppose the set of newly sampled interior and exterior points is denoted as \\(\\mathcal{P}_{\\mathcal{M}}\\), where \\(M\\) is the number of points. Define the \\(m\\)th point in \\(\\mathcal{P}_{\\mathcal{M}}\\) as \\(\\pmb{x}_m\\) and its corresponding SDF value as \\(s_m\\). In the domain of DeepSDF [31], a 3D shape can be represented by a latent code \\(z \\in \\mathbb{R}^{256}\\) in the latent space. The complete shape is obtained by optimizing \\(z\\) via Maximum a Posterior estimation:" + }, + { + "type": "equation", + "bbox": [ + 0.516, + 0.632, + 0.892, + 0.672 + ], + "angle": 0, + "content": "\\[\n\\hat {z} = \\frac {1}{\\sigma^ {2}} \\| z \\| _ {2} ^ {2} + \\underset {\\boldsymbol {z}} {\\arg \\min } \\sum_ {m = 1} ^ {M} \\mathcal {L} _ {1} \\left(f _ {\\theta} \\left(\\boldsymbol {z}, \\boldsymbol {x} _ {m}\\right), s _ {m}\\right), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.682, + 0.895, + 0.758 + ], + "angle": 0, + "content": "where \\(\\mathcal{L}_1\\) represents the clamped \\(\\mathcal{L}_1\\) distance and \\(\\sigma\\) is a regularization hyperparameter. Once the optimal latent code \\(\\hat{\\boldsymbol{z}}\\) is determined, the complete 3D shape can be recovered by finding the zero-SDF-value isosurface through the DeepSDF decoder \\(f(\\cdot)\\), which is defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.645, + 0.769, + 0.892, + 0.786 + ], + "angle": 0, + "content": "\\[\n\\hat {s} = f _ {\\theta} (\\hat {\\boldsymbol {z}}, \\boldsymbol {x}), \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.895, + 0.903 + ], + "angle": 0, + "content": "where \\(\\theta\\) represents the parameters of the decoder, \\(\\pmb{x} \\in \\mathbb{R}^3\\) denotes the 3D coordinates of the querying point, and \\(\\hat{s}\\) denotes the estimated SDF value given by \\(f(\\cdot)\\). Here, the sign of \\(\\hat{s}\\), either positive or negative, indicates whether the point lies on the exterior or interior of the surface, respectively. Thus, the surface of the object can be implicitly represented by the isosurface composed of points with zero SDF values." + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8308" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.304 + ], + "angle": 0, + "content": "Despite its simplicity and efficiency, DeepSDF only takes the given surface points into consideration when generating 3D shapes (i.e., Eq. (1)). This can lead to suboptimal reconstruction results in areas not captured by the partial point clouds since DeepSDF will reconstruct arbitrarily based on prior knowledge learned during training. For instance, referencing the ground truth of Case 1 in Figure 3, the reconstruction results of DeepSDF for Cases 2, 3, and 4 only demonstrate high fidelity in areas with well-captured surface points. The missing areas are reconstructed arbitrarily. To resolve this problem, we analyze multi-sweep consistency and complementarity in the latent feature space and propose implicit modeling with multi-sweep point clouds in MV-DeepSDF." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.314, + 0.269, + 0.33 + ], + "angle": 0, + "content": "3.2. Approach Overview" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.337, + 0.47, + 0.382 + ], + "angle": 0, + "content": "As shown in Figure 2, there are three main steps in MV-DeepSDF, namely preprocessing, optimal latent code prediction, and 3D mesh extraction." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.383, + 0.47, + 0.457 + ], + "angle": 0, + "content": "1) Preprocessing. First, we carry out Farthest Point Sampling (FPS) [33] to sample a fixed number of points on each raw partial point cloud since our global feature extractor requires standardized point clouds as input. For FPS, the number of centroids is set as 256." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.459, + 0.47, + 0.653 + ], + "angle": 0, + "content": "2) Optimal Latent Code Prediction. The post-FPS point clouds are used as input into the global feature extractor (yellow block in Figure 2) to extract global features for each individual point cloud. Meanwhile, the original point clouds are used to extract latent codes for each partial point cloud through the pre-trained DeepSDF (green block in Figure 2). Then, as shown in the red block of Figure 2, the global features and latent codes are concatenated as element-level representations, followed by an average pooling operation to aggregate the information into a single instance tensor. Finally, this instance tensor is transformed into the predicted latent code by a fully-connected layer as the set-level representation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.656, + 0.47, + 0.761 + ], + "angle": 0, + "content": "3) 3D Mesh Extraction. The predicted latent code is converted to an SDF using a pre-trained DeepSDF decoder [31]. The isosurface composed of querying points with zero SDF values represents the surface of the instance and the implicit surface can be rasterized to a 3D mesh using Marching Cubes [24]. Since the SDF is a continuous function, it supports 3D mesh extraction at any resolution." + }, + { + "type": "list", + "bbox": [ + 0.076, + 0.383, + 0.47, + 0.761 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.771, + 0.45, + 0.789 + ], + "angle": 0, + "content": "3.3. Consistency and Complementarity Analysis" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.469, + 0.902 + ], + "angle": 0, + "content": "Background. In literature [37, 50], multi-view consistency refers to the consistency of describing the same instance from different viewpoint observations and multi-view complementarity refers to the complementary information of the same instance provided by different observations. Existing methods mainly explore multi-view consistency and complementarity for 3D reconstruction with par" + }, + { + "type": "image", + "bbox": [ + 0.507, + 0.09, + 0.88, + 0.19 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.198, + 0.895, + 0.269 + ], + "angle": 0, + "content": "Figure 3. The 3D reconstruction results of DeepSDF [31] (row 2) using different point clouds (row 1). All point clouds are sampled from the same CAD model of ShapeNetV2 [7]. Case 1 shows the complete dense point cloud used to train the DeepSDF decoder, while Cases 2, 3, and 4 show the partial point clouds." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.292, + 0.797, + 0.307 + ], + "angle": 0, + "content": "tial point clouds in explicit modeling [34, 3]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.308, + 0.892, + 0.444 + ], + "angle": 0, + "content": "However, existing methods are not applicable for exploring multi-sweep/-view consistency and complementarity in implicit modeling because the abstract feature space operates differently than the explicit space. In implicit modeling, point clouds are expressed as low-dimensional feature vectors (a.k.a. latent vectors) in the latent feature space and the latent vectors are generated through a non-linear learning process that projects the 3D space to the feature space through a deep neural network [31, 32, 33, 49]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.462, + 0.893, + 0.55 + ], + "angle": 0, + "content": "Theoretical Analysis. Despite these differences, we can still explore multi-sweep consistency and complementarity in the latent feature space for implicit modeling. Inspired by [25], consider a total of \\(B\\) observations. The latent code for the \\(i\\)th observation, denoted by \\(z_{i}\\), can be represented as:" + }, + { + "type": "equation", + "bbox": [ + 0.62, + 0.553, + 0.891, + 0.568 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {z} _ {i} = \\boldsymbol {z} _ {i, c} + \\boldsymbol {z} _ {i, s} + \\boldsymbol {e} _ {i}, \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.575, + 0.892, + 0.621 + ], + "angle": 0, + "content": "where \\(i = \\{1,\\dots ,B\\}\\) \\(z_{i,c}\\) is the consistent component, \\(z_{i,s}\\) is the specific component, and \\(e_i\\) is the error component. In this work, \\(z_{i,c}\\) and \\(z_{i,s}\\) can be defined as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.525, + 0.648, + 0.892, + 0.664 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {z} _ {i, c} = \\boldsymbol {z} _ {i} \\cap \\boldsymbol {z} _ {g t} \\quad \\text {a n d} \\quad \\left(\\boldsymbol {z} _ {i, s} + \\boldsymbol {e} _ {i}\\right) = \\boldsymbol {z} _ {g t} - \\boldsymbol {z} _ {i}, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.675, + 0.893, + 0.902 + ], + "angle": 0, + "content": "where \\( \\mathbf{z}_{gt} \\) is the latent code corresponding to the ground truth shape and '∩' and '−' represent the similarity and difference in information captured by the two feature vectors, respectively. Now, consider any two consistent components \\( \\mathbf{z}_{i,c} \\) and \\( \\mathbf{z}_{j,c} \\). In the first case where \\( \\mathbf{z}_{i,c} \\cap \\mathbf{z}_{j,c} = \\emptyset \\), the two components contain completely different consistent information, which is complementary. In the second case where \\( \\mathbf{z}_{i,c} \\cap \\mathbf{z}_{j,c} \\neq \\emptyset \\), but \\( \\mathbf{z}_{i,c} \\nsubseteq \\mathbf{z}_{j,c} \\) and \\( \\mathbf{z}_{j,c} \\nsubseteq \\mathbf{z}_{i,c} \\), the two components contain some different information, which can be aggregated as complementary information to approach the ground truth. In the final case where \\( \\mathbf{z}_{i,c} \\cap \\mathbf{z}_{j,c} \\neq \\emptyset \\), but \\( \\mathbf{z}_{i,c} \\subseteq \\mathbf{z}_{j,c} \\) or \\( \\mathbf{z}_{j,c} \\subseteq \\mathbf{z}_{i,c} \\), either \\( \\mathbf{z}_{i,c} \\) or \\( \\mathbf{z}_{j,c} \\) contains redundant information from the other component. While redundant, this will not adversely impact complementary aggregation. Thus, to make the optimal \\( \\hat{\\mathbf{z}} \\) approach the ground" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8309" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.122 + ], + "angle": 0, + "content": "truth \\( z_{gt} \\), it is desired to aggregate all consistent and complementary information among all individual features:" + }, + { + "type": "equation", + "bbox": [ + 0.167, + 0.135, + 0.469, + 0.151 + ], + "angle": 0, + "content": "\\[\n\\hat {z} = z _ {1, c} \\cup z _ {2, c} \\dots \\cup z _ {B, c} + p, \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.163, + 0.469, + 0.284 + ], + "angle": 0, + "content": "where \\(\\cup\\) refers to the complementary aggregation of information among features and \\(p\\) denotes the predicted information for regions not captured in the multi-sweeps (e.g., the side of the vehicle not captured by the multi-sweeps as shown in the Cases 3 and 4 of Figure 3). In summary, with implicit modeling, we can learn the optimal latent code \\(\\hat{z}\\) by aggregating consistent (Eqs. (3)-(4)) and complementary (Eq. (5)) information among multi-sweeps." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.293, + 0.398, + 0.31 + ], + "angle": 0, + "content": "3.4. Architecture Design of MV-DeepSDF" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.317, + 0.469, + 0.422 + ], + "angle": 0, + "content": "To take advantage of multi-sweep consistency and complementarity in the latent feature space, we design a new architecture for implicit modeling. Our proposed architecture uses multi-sweep point clouds as model input and generates an optimal estimation of the 3D shape in the implicit space (a.k.a. the optimal latent code) as the output. The functionality of the network can be formulated as:" + }, + { + "type": "equation", + "bbox": [ + 0.194, + 0.435, + 0.469, + 0.452 + ], + "angle": 0, + "content": "\\[\ng _ {\\alpha} (\\boldsymbol {Z}, \\boldsymbol {P}) = \\hat {\\boldsymbol {z}} \\rightarrow \\boldsymbol {z} _ {g t}, \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.463, + 0.469, + 0.629 + ], + "angle": 0, + "content": "where \\( g(\\cdot) \\) denotes the desired network with associated parameters \\( \\alpha, Z = \\{z_1, \\dots, z_B\\} \\) denotes the set of latent codes, \\( B \\) represents the number of observations or latent codes, \\( P = \\{\\mathcal{P}_1, \\dots, \\mathcal{P}_B\\} \\) denotes the set of multi-view point clouds, and \\( \\hat{z} \\in \\mathbb{R}^{256} \\) and \\( z_{gt} \\in \\mathbb{R}^{256} \\) represent the estimated optimal and ground truth latent codes, respectively. Hence, the goal is converted into learning a network to make \\( \\hat{z} \\) approach \\( z_{gt} \\) for subsequent reconstructions. To this end, we devise a new architecture to realize the functionality required by simultaneously learning global features and latent codes for generating predicted latent codes." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.63, + 0.469, + 0.901 + ], + "angle": 0, + "content": "Specifically, inspired by PointNet [32], a pioneering work for 3D classification and segmentation, we transform the problem of shape estimation in the implicit space into an element-to-set feature extraction problem. Given a point cloud containing a set of 3D points, where all 3D points consistently describe a single object since they all belong to the same instance, we can learn a global feature for each point cloud that aggregates complementary features from each individual 3D point. However, only learning a global feature cannot be used for 3D reconstruction, so we propose to abstract the pipeline of PointNet (see Figure 4(a)) into a generalized process (see Figure 4(b)). As shown in Figure 4(a), PointNet first computes 3D point features using a shared MLP on each 3D point and then transforms these point features into a single global feature through max pooling. Now, suppose there exists a set composed of multiple elements. The goal of the generalized pipeline is to extract a feature for the entire set by aggregating all elements. To this" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.089, + 0.892, + 0.215 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.222, + 0.892, + 0.278 + ], + "angle": 0, + "content": "Figure 4. Comparison of three pipelines. (a) The pipeline of PointNet [32]. (b) The pipeline of an abstract generalized process to extract the set feature from the elements. (c) The proposed pipeline to extract the instance feature from multi-sweep point clouds." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.306, + 0.892, + 0.381 + ], + "angle": 0, + "content": "end, we propose two generalized operations. As shown in Figure 4(b), we define operation 1 as the computation of the element features (e.g., the shared MLP in PointNet) and operation 2 as the transformation of the element features into a set feature (e.g., the max pooling operation in PointNet)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.383, + 0.893, + 0.761 + ], + "angle": 0, + "content": "Using this generalized process, we can now devise our architecture to simultaneously learn global features and latent codes for generating predicted latent codes. First, we construct a global feature extractor (see yellow block in Figure 2) for learning a global feature for each point cloud that aggregates complementary features from each individual 3D point. The architecture of this feature extractor is inspired by the PCN encoder [49], a variant of PointNet [32]. This block is a stack of four PointNet [32] encoders with 128, 256, 512, and 1024 units, respectively. Since this architecture is inspired by the PCN encoder [49] and its global feature extraction operation is applied to every individual point cloud, we name it shared PCN. Meanwhile, to exploit the implicit information of each element, we employ a pre-trained DeepSDF [31] model (as denoted by Eq. (1)) to generate a latent code for each partial point cloud. Next, we concatenate the global features and latent codes to generate the element-level representations. Then, we employ average pooling and mapping to aggregate the element-level representations into a set-level predicted latent code. As shown in Figure 4(c), operation 1 of our pipeline consists of a global feature extractor and a pre-trained DeepSDF model, while operation 2 consists of concatenation, average pooling, and mapping. This pipeline realizes a symmetric operation on unordered multi-sweep point clouds." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.774, + 0.787, + 0.79 + ], + "angle": 0, + "content": "3.5. Model Training of MV-DeepSDF" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.799, + 0.89, + 0.828 + ], + "angle": 0, + "content": "We adopt a curriculum learning strategy for model training, which consists of two stages." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Stage One. In stage one, we pre-train the DeepSDF decoder using watertight CAD models belonging to the car taxonomy of the ShapeNetV2 dataset [7]. The latent code \\( z \\)" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8310" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.454, + 0.108 + ], + "angle": 0, + "content": "and parameters of the decoder \\(\\theta\\) are jointly optimized as:" + }, + { + "type": "equation", + "bbox": [ + 0.088, + 0.117, + 0.469, + 0.172 + ], + "angle": 0, + "content": "\\[\n\\underset {\\theta , \\left\\{\\boldsymbol {z} _ {j} \\right\\} _ {j = 1} ^ {J}} {\\arg \\min } \\sum_ {j = 1} ^ {J} \\left(\\frac {1}{\\sigma^ {2}} \\left\\| \\boldsymbol {z} _ {j} \\right\\| _ {2} ^ {2} + \\sum_ {k = 1} ^ {K} \\mathcal {L} _ {1} \\left(f _ {\\theta} \\left(\\boldsymbol {z} _ {j}, \\boldsymbol {x} _ {k}\\right), s _ {k}\\right)\\right), \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.173, + 0.47, + 0.264 + ], + "angle": 0, + "content": "where \\( J \\) represents the number of 3D shapes used for training and \\( K \\) represents the number of points for each shape. During this stage, the decoder gains prior knowledge of vehicle shapes and once trained, the decoder remains fixed for the latent code generation step of our pipeline. Please refer to [31] for the details of the training at this step." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.282, + 0.473, + 0.75 + ], + "angle": 0, + "content": "Training Dataset Preparation for Stage Two. As shown in Eq. (6), ground truth latent codes, partial point clouds, and their corresponding latent codes are required for training the reconstruction network. However, real-world datasets, such as Waymo [36] and KITTI [15], do not contain ground truth shapes, so it is necessary to use a synthetic dataset [7] for generating the training data. To resolve this problem, we utilize the latent codes of the training shapes (e.g., the complete dense point cloud shown in Case 1 of Figure 3) as ground truth latent codes in the second stage of model training. As for the partial point clouds, the domain gap between training instances and in-the-wild instances directly determines the ability of our network to generalize to real-world datasets. To reduce the domain gap, we adopt PCGen [23] as our partial point cloud generation method. PCGen places a virtual LiDAR with real-world parameters (resolution and sampling pattern) around the vehicle and simulates the point cloud captured by the virtual LiDAR. This differs from the method used by DeepSDF [31], where a simulated depth camera is used as the virtual sensor instead of a LiDAR. A visual comparison of the real-world point cloud and simulated partial point clouds obtained using various methods is given in Figure 5. As shown in Figure 5, the partial point clouds of PCGen [23] are visually closer to the in-the-wild LiDAR sweeps of Waymo [36] and KITTI [15] than those of the virtual depth camera approach [31], which only raycasts evenly in the inclination and azimuth directions. Apart from this visual superiority, the advantages of generating partial point clouds with PCGen can also be observed through the improved generalization ability of our network. See experiments for further details." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.473, + 0.904 + ], + "angle": 0, + "content": "When generating training data from ShapeNetV2 [7], we randomly sample one side of the vehicle to accurately reflect the real-world scan of a LiDAR on an ego-vehicle. In this way, we produce six partial point clouds for each vehicle. The virtual LiDAR pose for each partial point cloud is generated using a set of restrictions. These restrictions are set by considering the possible relative poses of an ego vehicle's LiDAR in the coordinate system of the other vehicle. In particular, \\(\\theta \\in [0^{\\circ}, 180^{\\circ}]\\) or \\(\\theta \\in [-180^{\\circ}, 0^{\\circ}]\\), \\(r \\in [3, 15]\\), and \\(h \\in [0.8, 1.2]\\) are used, where \\(\\theta\\) represents the azimuth," + }, + { + "type": "image", + "bbox": [ + 0.52, + 0.089, + 0.695, + 0.172 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.6, + 0.173, + 0.621, + 0.183 + ], + "angle": 0, + "content": "(c)" + }, + { + "type": "image", + "bbox": [ + 0.702, + 0.09, + 0.877, + 0.172 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.779, + 0.173, + 0.799, + 0.183 + ], + "angle": 0, + "content": "(d)" + }, + { + "type": "image", + "bbox": [ + 0.621, + 0.173, + 0.779, + 0.213 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.691, + 0.212, + 0.709, + 0.223 + ], + "angle": 0, + "content": "(e)" + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.231, + 0.895, + 0.344 + ], + "angle": 0, + "content": "Figure 5. Visual comparison of in-the-wild partial point clouds and raycasted point clouds. (a) A partial point cloud from the Waymo tracking dataset [36]. (b) The raycasted point cloud generated by PCGen [23] using the LiDAR parameters of Waymo. (c) A partial point cloud from the KITTI tracking dataset [15]. (d) The raycasted point cloud generated by PCGen [23] using the LiDAR parameters of KITTI. (e) The raycasted point cloud obtained from the virtual depth camera approach used by DeepSDF [31]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.368, + 0.892, + 0.476 + ], + "angle": 0, + "content": "\\(r\\) represents the distance between the LiDAR and the vehicle, and \\(h\\) represents the height of the LiDAR to the ground. \\(\\theta, r,\\) and \\(h\\) describes the pose of the virtual LiDAR with respect to the frame of the other vehicle. Both \\(r\\) and \\(h\\) are expressed in the normalized space, where the size of the vehicle is normalized into the range \\([-1, 1]\\). Finally, we generate a latent code for each partial point cloud using Eq. (1)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.494, + 0.893, + 0.661 + ], + "angle": 0, + "content": "Stage Two. In stage two, the network is trained to reconstruct 3D vehicles from multi-view partial point clouds and their corresponding latent codes. Consider the \\( c \\)th vehicle instance. Let \\( P_{B,c} \\) represent the set of partial point clouds, \\( Z_{B,c} \\) represent the set of latent codes corresponding to the multi-view point clouds, and \\( z_{gt,c} \\) represent the ground truth latent code acquired from stage one. Furthermore, let \\( g(\\cdot) \\) represent the function of the implicit shape prediction network (refer to yellow and red blocks in Figure 2) and \\( \\alpha \\) represent the parameters of the model. The training objective of stage two can be defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.558, + 0.673, + 0.892, + 0.713 + ], + "angle": 0, + "content": "\\[\n\\underset {\\alpha} {\\arg \\min } \\sum_ {c = 1} ^ {C} \\mathcal {L} _ {2} \\left(g _ {\\alpha} \\left(\\boldsymbol {Z} _ {B, c}, \\boldsymbol {P} _ {B, c}\\right), \\boldsymbol {z} _ {g t, c}\\right), \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.724, + 0.895, + 0.772 + ], + "angle": 0, + "content": "where \\(C\\) represents the number of instances employed for training and \\(\\mathcal{L}_2\\) is the Mean Squared Error loss. The training details are presented in Sec. 4.1." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.785, + 0.634, + 0.803 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.894, + 0.9 + ], + "angle": 0, + "content": "In this section, we present qualitative and quantitative results on two real-world autonomous driving datasets, namely Waymo [36] and KITTI [15]. The multi-sweep point clouds for Waymo are collected from 136 unique vehicle instances of Waymo Open Dataset's tracking data [36], while those for KITTI are extracted from 233 vehicle in" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.515, + 0.958 + ], + "angle": 0, + "content": "8311" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.09, + 0.891, + 0.263 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.27, + 0.893, + 0.298 + ], + "angle": 0, + "content": "Figure 6. Visual comparison with the state-of-the-art methods (DeepSDF [31], C-DeepSDF [11], MendNet [12], and AdaPoinTr [48]) on the Waymo [36] dataset. DeepSDF+MS and MendNet+MS indicate the models with multi-sweep input." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.323, + 0.47, + 0.384 + ], + "angle": 0, + "content": "stances of KITTI's tracking dataset [15]. Due to page limitations, experiment details and some results (e.g., the results on the synthetic dataset ShapeNetV2 [7]) are discussed in the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.391, + 0.295, + 0.407 + ], + "angle": 0, + "content": "4.1. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.415, + 0.471, + 0.581 + ], + "angle": 0, + "content": "Architecture Details. Our global feature extractor, named shared PCN, is a variant of the PCN encoder [49]. The embedded shared MLP layers are identical to those of PointNet [32], which are implemented using 1D convolution layers. Moreover, since DeepSDF [31] normalizes the latent codes into the range \\([-1, 1]\\), we add a tanh layer after the last shared MLP to normalize the global features into the same range as the latent codes. The decoder is identical to that of DeepSDF [31]. We report results based on an implementation with Python and PyTorch, but our approach also supports implementation with MindSpore [20]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.598, + 0.47, + 0.84 + ], + "angle": 0, + "content": "Training Details. In the first stage of training, we follow the same method as presented in DeepSDF [31] to train the decoder using watertight CAD models from the car taxonomy of ShapeNetV2 [7]. Once trained, the decoder is fixed and projects a 256-dimensional latent code to an SDF in 3D space. In the second stage, we train the model for 20 epochs using the Adam optimizer [21] with a learning rate of 1e-5. The batch size is set to 1, allowing the model to simultaneously see all 6 frames of the given instance at each iteration. Since both the output of the model and the supervision are 1D vectors, the loss computation is very fast. It only takes 10 minutes to train our network on a single NVIDIA GeForce RTX 2080 GPU during stage two. However, the DeepSDF decoder [31] used to prepare the training dataset for stage two through latent code generation is a more time-consuming process." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.848, + 0.267, + 0.862 + ], + "angle": 0, + "content": "4.2. Evaluation Protocol" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.871, + 0.469, + 0.901 + ], + "angle": 0, + "content": "Metrics. Since an in-the-wild instance does not have a ground truth 3D shape, we follow [12] to evaluate the recon" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.323, + 0.892, + 0.442 + ], + "angle": 0, + "content": "struction results. In particular, the multiple LiDAR sweeps are stacked to construct the ground truth points set \\( \\pmb{X} \\). Moreover, we sample 30,000 points on the surface of each reconstructed mesh to generate the reconstruction points set \\( \\pmb{Y} \\). We employ Asymmetric Chamfer Distance (ACD) [12], which is the sum of the squared distance of each ground truth point to the nearest point in the reconstructed point set, to evaluate reconstruction results on real-world datasets:" + }, + { + "type": "equation", + "bbox": [ + 0.573, + 0.449, + 0.892, + 0.48 + ], + "angle": 0, + "content": "\\[\n\\operatorname {A C D} \\left(\\boldsymbol {X}, \\boldsymbol {Y}\\right) = \\sum_ {\\boldsymbol {x} \\in \\boldsymbol {X}} \\min _ {\\boldsymbol {y} \\in \\boldsymbol {Y}} \\| x - \\boldsymbol {y} \\| _ {2} ^ {2}. \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.487, + 0.891, + 0.532 + ], + "angle": 0, + "content": "For ACD, a smaller value is preferred. In addition, we compute the recall of the ground truth points from the reconstructed shape, which is defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.51, + 0.538, + 0.892, + 0.575 + ], + "angle": 0, + "content": "\\[\n\\operatorname {R e c a l l} (\\boldsymbol {X}, \\boldsymbol {Y}) = \\frac {1}{| \\boldsymbol {X} |} \\sum_ {x \\in \\boldsymbol {X}} \\left[ \\min _ {y \\in \\boldsymbol {Y}} \\| x - y \\| _ {2} ^ {2} < = t \\right], \\tag {10}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.581, + 0.828, + 0.596 + ], + "angle": 0, + "content": "where the threshold \\(t\\) is set as 0.1, following [12]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.614, + 0.893, + 0.901 + ], + "angle": 0, + "content": "Competitors. We compare our approach with four state-of-the-art methods, including three implicit modeling-based methods (DeepSDF [31], C-DeepSDF [11], and MendNet [12]) and AdaPoinTr [48], which is built upon PoinTr++ [47], the winner of Multi-View Partial Point Cloud Challenge 2021 on Completion and Registration [30]. Training data for DeepSDF and C-DeepSDF are generated following the original papers, while MendNet uses PCGen [23] to generate training data. The pipeline of AdaPoinTr [48] requires online generation of partial point clouds using the virtual depth camera approach and since it is not trivial to replace this process with PCGen, AdaPoinTr is trained using the default setup without PCGen. Note that with multi-sweep point clouds, competitors generate multiple reconstruction results (one for each partial point cloud), so we compare with the best single-shot reconstruction result, which is the mesh with the minimum ACD among the multiple single-shot reconstructed meshes. Furthermore, we report the results of DeepSDF and MendNet with multi-sweep" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8312" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.084, + 0.089, + 0.464, + 0.218 + ], + "angle": 0, + "content": "
Method \\ MetricACDmean ↓ACDmedian ↓Recall ↑
DeepSDF [31]6.265.8193.51
DeepSDF+MS5.125.0995.57
C-DeepSDF [11]6.215.6493.98
MendNet [12]4.924.7995.39
MendNet+MS4.854.7795.76
AdaPoinTr*[48]4.794.7495.95
Ours-VDC4.764.5596.05
Ours3.362.2696.84
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.077, + 0.218, + 0.468, + 0.314 + ], + "angle": 0, + "content": "Table 1. Comparison with the state-of-the-art methods on Waymo. ACD \\(\\downarrow\\) is multiplied by \\(10^{3}\\). Recall \\(\\uparrow\\) is presented as a percentage. *AdaPoinTr is trained with the default setup without PCGen on the large-scale ShapeNet-55 [47] following the original paper [48], and then fine-tuned on the car taxonomy of ShapeNetV2 in our experiments. Other methods are only trained with the car taxonomy of ShapeNetV2." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.34, + 0.468, + 0.46 + ], + "angle": 0, + "content": "inputs (denoted as DeepSDF+MS and MendNet+MS), in which we stack the partial point clouds of multi-sweeps into a single point cloud and perform single-shot-based reconstruction on this stacked point cloud. For our approach, in addition to the default setup which generates the training dataset using PCGen (denoted as Ours), we also adapt our approach to use training data generated by the virtual depth camera approach [31] (denoted as Ours-VDC)." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.47, + 0.255, + 0.485 + ], + "angle": 0, + "content": "4.3. Results on Waymo" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.493, + 0.468, + 0.704 + ], + "angle": 0, + "content": "The qualitative and quantitative comparisons of our approach with the state-of-the-art methods are presented in Figure 6 and Table 1, respectively. Overall, our approach achieves the best reconstruction results both qualitatively and quantitatively. Specifically, from Figure 6 and Table 1, we can see that DeepSDF [31] and C-DeepSDF [11] are sensitive to noise, resulting in low fidelity. MendNet [12] generates more stable results than DeepSDF and C-DeepSDF, but its reconstruction meshes contain some irregular holes on the surface (see sixth column of Figure 6). Although AdaPoinTr [48] outputs point clouds with good fidelity, it expresses the shape with a limited resolution and thus fails to describe continuous local details (see seventh column of Figure 6)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.705, + 0.468, + 0.9 + ], + "angle": 0, + "content": "Compared with vanilla DeepSDF and MendNet, DeepSDF+MS and MendNet+MS yield messier surfaces/structures (see fourth and eighth columns of Figure 6), despite their better metric scores. This shows that even though transforming all partial point clouds into a single frame does benefit information aggregation, it also accumulates noise and annotation errors in the process. Hence, due to noise in real-world data, it is not practical to geometrically stack multi-sweep point clouds and directly perform single-shot-based reconstruction. In comparison, our approach generates smooth watertight shapes (see last two columns of Figure 6) with high fidelity (see Table 1). Furthermore, Ours outperforms Ours-VDC, which indicates" + }, + { + "type": "table", + "bbox": [ + 0.507, + 0.09, + 0.886, + 0.218 + ], + "angle": 0, + "content": "
Method \\ MetricACDmean ↓ACDmedian ↓Recall ↑
DeepSDF [31]6.816.1780.65
DeepSDF+MS6.115.8382.73
C-DeepSDF [11]6.735.9980.77
MendNet [12]5.945.6483.84
MendNet+MS5.835.6184.26
AdaPoinTr [48]5.895.6784.20
Ours-VDC5.755.2484.39
Ours4.273.0185.88
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.5, + 0.218, + 0.89, + 0.245 + ], + "angle": 0, + "content": "Table 2. Comparison with the state-of-the-art methods on KITTI. ACD \\( \\downarrow \\) is multiplied by \\( {10}^{3} \\) . Recall \\( \\uparrow \\) is presented as a percentage." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.272, + 0.892, + 0.316 + ], + "angle": 0, + "content": "that using PCGen to prepare training partial point clouds (refer to Figure 5) reduces the domain gap between training and in-the-wild instances." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.328, + 0.673, + 0.344 + ], + "angle": 0, + "content": "4.4. Results on KITTI" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.352, + 0.892, + 0.533 + ], + "angle": 0, + "content": "The qualitative and quantitative comparisons of our approach against the state-of-the-art methods are presented in Figure 7 and Table 2, respectively. From these results, we can also observe the superior performance of our approach over the state-of-the-art competitors. Specifically, qualitatively, as shown in Figure 7, our approaches (Ours and Ours-VDC) are more robust to noise when compared to DeepSDF [31], DeepSDF+MS, and C-DeepSDF [11] and generate smoother, watertight surfaces compared to MendNet [12], AdaPoinTr [48], and MendNet+MS. Quantitatively, as shown in Table 2, Ours yields the best ACD and Recall results, while Ours-VDC performs the second best." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.545, + 0.654, + 0.56 + ], + "angle": 0, + "content": "4.5. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.569, + 0.892, + 0.901 + ], + "angle": 0, + "content": "To verify the effectiveness of the main components of our approach, we carry out a series of experiments on Waymo [36] as shown in Table 3. The first row of Table 3 refers to the baseline model of our approach, which is a shared PCN encoder (Enc.) (yellow block in Figure 2) followed by an average pooling layer (Avg.). This architecture is similar to that of MendNet [12], which adds two stacked PointNet encoders [32] to the DeepSDF decoder. In the second row, we directly use bitwise multiplication to merge the global features \\((\\mathrm{B} \\times 256\\), instead of \\(\\mathrm{B} \\times 1024)\\) and the latent codes \\((\\mathrm{B} \\times 256)\\). However, this results in obvious performance degradation, which shows that directly merging the global features and latent codes obtained from multi-sweep information does not bring improvement to our baseline model. In comparison, in the third row, we add our proposed components, namely the input of latent codes (Dep.), concatenation (Con.), and mapping (Map.), to the baseline model, but with max pooling. This brings significant performance improvement compared to the first and second rows. Then, in the last row, we further replace max pooling with average pooling, which includes all proposed components of this work. This yields the best results." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8313" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.09, + 0.892, + 0.263 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.267, + 0.893, + 0.297 + ], + "angle": 0, + "content": "Figure 7. Visual comparison with the state-of-the-art methods (DeepSDF [31], C-DeepSDF [11], MendNet [12], and AdaPoinTr [48]) on the KITTI [15] dataset. DeepSDF+MS and MendNet+MS indicate the models with multi-sweep input." + }, + { + "type": "table", + "bbox": [ + 0.086, + 0.319, + 0.462, + 0.408 + ], + "angle": 0, + "content": "
Operation 1Operation 2Metric
Enc.Dep.Mer.PoolMap.ACD ↓Recall ↑
✓Avg.4.8995.50
✓✓Mul.Avg.7.3384.93
✓✓Con.Max.✓4.3596.61
✓✓Con.Avg.✓3.3696.84
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.076, + 0.408, + 0.468, + 0.519 + ], + "angle": 0, + "content": "Table 3. The ablation study of the proposed framework. Refer to Figure 4(b) to see the definitions of operations 1 and 2. Enc.: the shared PCN encoder; Dep.: latent code generation through DeepSDF as input; Mer.: the operation to merge global features and latent codes; Map.: the mapping conducted by the fully-connected layer; Con.: the concatenation; Mul.: the bitwise multiplication; Avg.: average pooling; Max.: max pooling. ACD \\(\\downarrow\\) is multiplied by \\(10^{3}\\). Recall \\(\\uparrow\\) is presented as a percentage." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.545, + 0.355, + 0.559 + ], + "angle": 0, + "content": "4.6. Extension to Other Taxonomies" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.568, + 0.47, + 0.809 + ], + "angle": 0, + "content": "It is straightforward to extend the proposed shape completion framework to other taxonomies. Suppose that we want to extend MV-DeepSDF to perform shape completion on sofas. First, a new DeepSDF decoder [31] needs to be pre-trained using watertight CAD models from the sofa taxonomy of ShapeNetV2 [7] or another synthetic dataset. Then, PCGen [23] or another sampling technique (e.g., the approaches proposed in [31, 47]) can be used to generate partial point clouds for each sofa instance. These partial point clouds are then passed into the pre-trained DeepSDF decoder [31] to produce their corresponding latent codes. Finally, the partial point clouds and latent codes can be used together to train MV-DeepSDF. Following the pipeline above, we evaluate on indoor sofas of ShapeNetV2 and outdoor cyclists of Waymo and show that our method is versatile and extendible to other taxonomies (see Figure 8)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.471, + 0.902 + ], + "angle": 0, + "content": "While existing datasets, such as ScanNet [8] and Semantic3D [18], provide real-world point cloud data for many taxonomies, the availability of tracking data for multisweep scans is still fairly limited to the autonomous driving industry. Hence, it is necessary to first obtain the corresponding multi-sweep tracking labels for the desired class" + }, + { + "type": "image", + "bbox": [ + 0.527, + 0.337, + 0.609, + 0.368 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.542, + 0.377, + 0.599, + 0.39 + ], + "angle": 0, + "content": "DeepSDF" + }, + { + "type": "image", + "bbox": [ + 0.623, + 0.339, + 0.705, + 0.371 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.655, + 0.378, + 0.683, + 0.389 + ], + "angle": 0, + "content": "Ours" + }, + { + "type": "image", + "bbox": [ + 0.725, + 0.323, + 0.785, + 0.375 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.727, + 0.378, + 0.782, + 0.389 + ], + "angle": 0, + "content": "DeepSDF" + }, + { + "type": "image", + "bbox": [ + 0.812, + 0.323, + 0.858, + 0.375 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.826, + 0.378, + 0.854, + 0.388 + ], + "angle": 0, + "content": "Ours" + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.398, + 0.892, + 0.426 + ], + "angle": 0, + "content": "Figure 8. Visual comparison of DeepSDF and MV-DeepSDF on the indoor sofa of ShapeNetV2 and the outdoor cyclist of Waymo." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.448, + 0.89, + 0.464 + ], + "angle": 0, + "content": "when choosing to adopt MV-DeepSDF on a new taxonomy." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.476, + 0.618, + 0.491 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.501, + 0.892, + 0.741 + ], + "angle": 0, + "content": "In this work, we propose a new MV-DeepSDF framework to facilitate implicit modeling with multi-sweep point clouds for autonomous driving. The main idea is to abstract 3D vehicle reconstruction from multi-sweeps into an element-to-set feature extraction problem. Namely, we consider the multi-sweeps of a vehicle as elements composing a set and infer the set feature, which is an optimal estimation of the 3D shape described in the abstract implicit space. In particular, we present a theoretical analysis of multi-sweep consistency and complementarity in the latent feature space. Guided by this analysis, we design a new architecture to optimally estimate the Signed Distance Function shape of a vehicle from its in-the-wild multi-sweep point clouds. Qualitative and quantitative evaluations on both real-world and synthetic datasets show the superiority of our approach over the state-of-the-art methods." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.742, + 0.892, + 0.803 + ], + "angle": 0, + "content": "Limitation. Despite promising results, our approach still relies on a synthetic 3D dataset to gain prior knowledge of 3D shapes for reconstruction. Exploring reconstruction by learning directly from real data is worthy of further study." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.816, + 0.659, + 0.832 + ], + "angle": 0, + "content": "Acknowledgments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.9 + ], + "angle": 0, + "content": "The authors gratefully acknowledge the support of MindSpore, CANN, and Ascend AI Processor. The authors would also like to thank Andrew Yang and Hunter Schofield for their assistance." + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8314" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.468, + 0.184 + ], + "angle": 0, + "content": "[1] Dejan Azinović, Ricardo Martin-Brualla, Dan B Goldman, Matthias Nießner, and Justus Thies. Neural rgb-d surface reconstruction. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6290-6301, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.187, + 0.468, + 0.228 + ], + "angle": 0, + "content": "[2] Heli Ben-Hamu, Haggai Maron, Itay Kezurer, Gal Avineri, and Yaron Lipman. Multi-chart generative surface modeling. ACM Transactions on Graphics, 37(6):1-15, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.231, + 0.468, + 0.273 + ], + "angle": 0, + "content": "[3] Paul J Besl and Neil D McKay. Method for registration of 3-d shapes. In Sensor fusion IV: control paradigms and data structures, volume 1611, pages 586-606. Spie, 1992." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.275, + 0.468, + 0.33 + ], + "angle": 0, + "content": "[4] Hongrui Cai, Wanquan Feng, Xuetao Feng, Yan Wang, and Juyong Zhang. Neural surface reconstruction of dynamic scenes with monocular rgb-d camera. In Proc. of Conference on Neural Information Processing Systems, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.332, + 0.468, + 0.401 + ], + "angle": 0, + "content": "[5] Yingjie Cai, Kwan-Yee Lin, Chao Zhang, Qiang Wang, Xiaogang Wang, and Hongsheng Li. Learning a structured latent space for unsupervised point cloud completion. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5543-5553, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.403, + 0.468, + 0.473 + ], + "angle": 0, + "content": "[6] Rohan Chabra, Jan E Lenssen, Eddy Ilg, Tanner Schmidt, Julian Straub, Steven Lovegrove, and Richard Newcombe. Deep local shapes: Learning local sdf priors for detailed 3d reconstruction. In Proc. of European Conference on Computer Vision, pages 608-625. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.475, + 0.468, + 0.543 + ], + "angle": 0, + "content": "[7] Angel X Chang, Thomas Funkhouser, Leonidas Guibas, Pat Hanrahan, Qixing Huang, Zimo Li, Silvio Savarese, Manolis Savva, Shuran Song, Hao Su, et al. Shapenet: An information-rich 3d model repository. arXiv preprint arXiv:1512.03012, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.546, + 0.468, + 0.615 + ], + "angle": 0, + "content": "[8] Angela Dai, Angel X Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 5828-5839, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.618, + 0.468, + 0.686 + ], + "angle": 0, + "content": "[9] Angela Dai, Christian Diller, and Matthias Nießner. Sg-nn: Sparse generative neural networks for self-supervised scene completion of rgb-d scans. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 849–858, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.689, + 0.468, + 0.757 + ], + "angle": 0, + "content": "[10] Angela Dai, Charles Ruizhongtai Qi, and Matthias Nießner. Shape completion using 3d-encoder-predictor cnns and shape synthesis. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 5868-5877, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.76, + 0.468, + 0.816 + ], + "angle": 0, + "content": "[11] Yueqi Duan, Haidong Zhu, He Wang, Li Yi, Ram Nevata, and Leonidas J Guibas. Curriculum deepsdf. In Proc. of European Conference on Computer Vision, pages 51-67. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.468, + 0.899 + ], + "angle": 0, + "content": "[12] Shivam Duggal, Zihao Wang, Wei-Chiu Ma, Sivabalan Manivasagam, Justin Liang, Shenlong Wang, and Raquel Urtasun. Mending neural implicit modeling for 3d vehicle reconstruction in the wild. In Proc. of IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1900-1909, 2022." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.468, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "[13] Francis Engelmann, Jörg Stuckler, and Bastian Leibe. Samp: shape and motion priors for 4d vehicle reconstruction. In Proc. of IEEE Winter Conference on Applications of Computer Vision, pages 400-408. IEEE, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.149, + 0.892, + 0.216 + ], + "angle": 0, + "content": "[14] Qiaojun Feng, Yue Meng, Mo Shan, and Nikolay Atanasov. Localization and mapping using instance-specific mesh models. In Proc. of IEEE/RSJ International Conference on Intelligent Robots and Systems, pages 4985-4991. IEEE, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.218, + 0.892, + 0.272 + ], + "angle": 0, + "content": "[15] Andreas Geiger, Philip Lenz, Christoph Stiller, and Raquel Urtasun. Vision meets robotics: The kitti dataset. The International Journal of Robotics Research, 32(11):1231-1237, 2013." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.274, + 0.892, + 0.342 + ], + "angle": 0, + "content": "[16] Thibault Groueix, Matthew Fisher, Vladimir G Kim, Bryan C Russell, and Mathieu Aubry. A papier-mâché approach to learning 3d surface generation. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 216-224, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.344, + 0.892, + 0.412 + ], + "angle": 0, + "content": "[17] Jiayuan Gu, Wei-Chiu Ma, Sivabalan Manivasagam, Wenyuan Zeng, Zihao Wang, Yuwen Xiong, Hao Su, and Raquel Urtasun. Weakly-supervised 3d shape completion in the wild. In Proc. of European Conference on Computer Vision, pages 283-299. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.414, + 0.892, + 0.467 + ], + "angle": 0, + "content": "[18] Timo Hackel, Nikolay Savinov, Lubor Ladicky, Jan D Wegner, Konrad Schindler, and Marc Pollefeys. Semantic3d. net: A new large-scale point cloud classification benchmark. arXiv preprint arXiv:1704.03847, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.469, + 0.892, + 0.537 + ], + "angle": 0, + "content": "[19] Tao Hu, Zhizhong Han, Abhinav Shrivastava, and Matthias Zwicker. Render4completion: Synthesizing multi-view depth maps for 3d shape completion. In Proc. of the IEEE/CVF International Conference on Computer Vision Workshops, pages 0–0, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.539, + 0.892, + 0.563 + ], + "angle": 0, + "content": "[20] Huawei. Mindspace. https://www.mindspore.cn/, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.567, + 0.892, + 0.607 + ], + "angle": 0, + "content": "[21] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. In Proc. of the International Conference on Learning Representations (Poster), 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.609, + 0.892, + 0.675 + ], + "angle": 0, + "content": "[22] Chen Kong, Chen-Hsuan Lin, and Simon Lucey. Using locally corresponding cad models for dense 3d reconstructions from a single image. In Proc. the IEEE conference on computer vision and pattern recognition, pages 4857-4865, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.678, + 0.892, + 0.718 + ], + "angle": 0, + "content": "[23] Chenqi Li, Yuan Ren, and Bingbing Liu. Pcgen: Point cloud generator for lidar simulation. In Proc. of International Conference on Robotics and Automation, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.72, + 0.892, + 0.76 + ], + "angle": 0, + "content": "[24] William E Lorensen and Harvey E Cline. Marching cubes: A high resolution 3d surface construction algorithm. ACM siggraph computer graphics, 21(4):163-169, 1987." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.762, + 0.892, + 0.815 + ], + "angle": 0, + "content": "[25] Shirui Luo, Changqing Zhang, Wei Zhang, and Xiaochun Cao. Consistent and specific multi-view subspace clustering. In Proc. of the AAAI conference on artificial intelligence, volume 32, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.818, + 0.892, + 0.871 + ], + "angle": 0, + "content": "[26] Xiaoxu Meng, Weikai Chen, and Bo Yang. Neat: Learning neural implicit surfaces with arbitrary topologies from multi-view images. Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, June 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.873, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[27] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks:" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.515, + 0.956 + ], + "angle": 0, + "content": "8315" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.471, + 0.133 + ], + "angle": 0, + "content": "Learning 3d reconstruction in function space. In Proc. of IEEE Conf. on Computer Vision and Pattern Recognition, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.47, + 0.191 + ], + "angle": 0, + "content": "[28] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.193, + 0.471, + 0.276 + ], + "angle": 0, + "content": "[29] Richard A Newcombe, Shahram Izadi, Otmar Hilliges, David Molyneaux, David Kim, Andrew J Davison, Pushmeet Kohi, Jamie Shotton, Steve Hodges, and Andrew Fitzgibbon. Kinectfusion: Real-time dense surface mapping and tracking. In Proc. IEEE international symposium on mixed and augmented reality, pages 127-136. Ieee, 2011." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.278, + 0.47, + 0.346 + ], + "angle": 0, + "content": "[30] Liang Pan, Tong Wu, Zhongang Cai, Ziwei Liu, Xumin Yu, Yongming Rao, Jiwen Lu, Jie Zhou, Mingye Xu, Xiaoyuan Luo, et al. Multi-view partial (mvp) point cloud challenge 2021 on completion and registration: Methods and results. arXiv preprint arXiv:2112.12053, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.349, + 0.471, + 0.417 + ], + "angle": 0, + "content": "[31] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. Deepsdf: Learning continuous signed distance functions for shape representation. In Proc. of the IEEE/CVF conference on computer vision and pattern recognition, pages 165-174, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.419, + 0.47, + 0.475 + ], + "angle": 0, + "content": "[32] Charles R Qi, Hao Su, Kaichun Mo, and Leonidas J Guibas. Pointnet: Deep learning on point sets for 3d classification and segmentation. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 652-660, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.477, + 0.47, + 0.532 + ], + "angle": 0, + "content": "[33] Charles Ruizhongtai Qi, Li Yi, Hao Su, and Leonidas J Guibas. Pointnet++: Deep hierarchical feature learning on point sets in a metric space. Advances in neural information processing systems, 30, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.533, + 0.471, + 0.588 + ], + "angle": 0, + "content": "[34] Radu Bogdan Rusu, Nico Blodow, and Michael Beetz. Fast point feature histograms (fpfh) for 3d registration. In Proc. of IEEE international conference on robotics and automation, pages 3212-3217. IEEE, 2009." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.59, + 0.47, + 0.658 + ], + "angle": 0, + "content": "[35] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5459-5469, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.661, + 0.471, + 0.743 + ], + "angle": 0, + "content": "[36] Pei Sun, Henrik Kretzschmar, Xerxes Dotiwalla, Aurelien Chouard, Vijaysai Patnaik, Paul Tsui, James Guo, Yin Zhou, Yuning Chai, Benjamin Caine, et al. Scalability in perception for autonomous driving: Waymo open dataset. In Proc. of the IEEE/CVF conference on computer vision and pattern recognition, pages 2446-2454, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.745, + 0.47, + 0.813 + ], + "angle": 0, + "content": "[37] Shubham Tulsiani, Alexei A Efros, and Jitendra Malik. Multi-view consistency as supervisory signal for learning shape and pose prediction. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 2897-2905, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.816, + 0.47, + 0.871 + ], + "angle": 0, + "content": "[38] Nitika Verma, Edmond Boyer, and Jakob Verbeek. Feastnet: Feature-steered graph convolutions for 3d shape analysis. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 2598-2606, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[39] Dan Wang, Xinrui Cui, Xun Chen, Zhengxia Zou, Tianyang Shi, Septimiu Salcudean, Z Jane Wang, and Rabab Ward." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "Multi-view 3d reconstruction with transformers. In Proc. of the IEEE/CVF International Conference on Computer Vision, pages 5722-5731, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[40] Nanyang Wang, Yinda Zhang, Zhuwen Li, Yanwei Fu, Wei Liu, and Yu-Gang Jiang. Pixel2mesh: Generating 3d mesh models from single rgb images. In Proc. of the European conference on computer vision, pages 52-67, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.193, + 0.892, + 0.247 + ], + "angle": 0, + "content": "[41] Peng Wang, Lingjie Liu, Yuan Liu, Christian Theobalt, Taku Komura, and Wenping Wang. Neus: Learning neural implicit surfaces by volume rendering for multi-view reconstruction. arXiv preprint arXiv:2106.10689, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.249, + 0.892, + 0.304 + ], + "angle": 0, + "content": "[42] Xiaogang Wang, Marcelo H Ang, and Gim Hee Lee. Voxel-based network for shape completion by leveraging edge generation. In Proc. of the IEEE/CVF international conference on computer vision, pages 13189-13198, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.305, + 0.892, + 0.374 + ], + "angle": 0, + "content": "[43] Haozhe Xie, Hongxun Yao, Shangchen Zhou, Jiageng Mao, Shengping Zhang, and Wenxiu Sun. Grnet: Gridding residual network for dense point cloud completion. In Proc. of the European conference on computer vision, pages 365-381. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.376, + 0.892, + 0.444 + ], + "angle": 0, + "content": "[44] Qiangeng Xu, Zexiang Xu, Julien Philip, Sai Bi, Zhixin Shu, Kalyan Sunkavalli, and Ulrich Neumann. Point-nerf: Point-based neural radiance fields. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5438-5448, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.446, + 0.892, + 0.514 + ], + "angle": 0, + "content": "[45] Jianglong Ye, Yuntao Chen, Naiyan Wang, and Xiaolong Wang. Gifs: Neural implicit function for general shape representation. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12829-12839, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.517, + 0.892, + 0.572 + ], + "angle": 0, + "content": "[46] Jianglong Ye, Yuntao Chen, Naiyan Wang, and Xiaolong Wang. Online adaptation for implicit object tracking and shape reconstruction in the wild. IEEE Robotics and Automation Letters, 7(4):8909-8916, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.574, + 0.892, + 0.641 + ], + "angle": 0, + "content": "[47] Xumin Yu, Yongming Rao, Ziyi Wang, Zuyan Liu, Jiwen Lu, and Jie Zhou. Pointr: Diverse point cloud completion with geometry-aware transformers. In Proc. of the IEEE/CVF international conference on computer vision, pages 12498-12507, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.644, + 0.892, + 0.698 + ], + "angle": 0, + "content": "[48] Xumin Yu, Yongming Rao, Ziyi Wang, Jiwen Lu, and Jie Zhou. Adapointr: Diverse point cloud completion with adaptive geometry-aware transformers. arXiv preprint arXiv:2301.04545, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.7, + 0.892, + 0.755 + ], + "angle": 0, + "content": "[49] Wentao Yuan, Tejas Khot, David Held, Christoph Mertz, and Martial Hebert. Pcn: Point completion network. In Proc. of International Conference on 3D Vision, pages 728-737, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.757, + 0.892, + 0.812 + ], + "angle": 0, + "content": "[50] Changqing Zhang, Zongbo Han, Huazhu Fu, Joey Tianyi Zhou, Qinghua Hu, et al. Cpm-nets: Cross partial multiview networks. Advances in Neural Information Processing Systems, 32, 2019." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.812 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8316" + } + ] +] \ No newline at end of file diff --git a/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/0f77204f-207d-45fd-9794-f340dac7f292_origin.pdf b/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/0f77204f-207d-45fd-9794-f340dac7f292_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..911f26d03a8b36e6935290fa5481bfb8b0464483 --- /dev/null +++ b/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/0f77204f-207d-45fd-9794-f340dac7f292_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:8b8050ef364fee08731fda01b00feafa7f45d972081186a45a529b494ea4e9df +size 8118334 diff --git a/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/full.md b/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/full.md new file mode 100644 index 0000000000000000000000000000000000000000..56ed4fe3a87516e2a5bacc2bc64278f31c50258c --- /dev/null +++ b/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/full.md @@ -0,0 +1,330 @@ +# MV-DeepSDF: Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving + +Yibo Liu $^{1,2}$ , Kelly Zhu $^{1,3}$ , Guile Wu $^{1}$ , Yuan Ren $^{1}$ , Bingbing Liu $^{1}$ , Yang Liu $^{1}$ , Jinjun Shan $^{2}$ $^{1}$ Huawei Noah's Ark Lab, $^{2}$ York University, $^{3}$ University of Toronto + +{yorklyb, jjshan}@yorku.ca, kellyk.zhu@mail.utoronto.ca +{guile.wu, yuan.ren3, liu.bingbing, yang.liu9}@huawei.com + +# Abstract + +Reconstructing 3D vehicles from noisy and sparse partial point clouds is of great significance to autonomous driving. Most existing 3D reconstruction methods cannot be directly applied to this problem because they are elaborately designed to deal with dense inputs with trivial noise. In this work, we propose a novel framework, dubbed MV-DeepSDF, which estimates the optimal Signed Distance Function (SDF) shape representation from multisweep point clouds to reconstruct vehicles in the wild. Although there have been some SDF-based implicit modeling methods, they only focus on single-view-based reconstruction, resulting in low fidelity. In contrast, we first analyze multi-sweep consistency and complementarity in the latent feature space and propose to transform the implicit space shape estimation problem into an element-to-set feature extraction problem. Then, we devise a new architecture to extract individual element-level representations and aggregate them to generate a set-level predicted latent code. This set-level latent code is an expression of the optimal 3D shape in the implicit space, and can be subsequently decoded to a continuous SDF of the vehicle. In this way, our approach learns consistent and complementary information among multi-sweeps for 3D vehicle reconstruction. We conduct thorough experiments on two real-world autonomous driving datasets (Waymo and KITTI) to demonstrate the superiority of our approach over state-of-the-art alternative methods both qualitatively and quantitatively. + +# 1. Introduction + +3D vehicle reconstruction from sparse and partial point clouds is a fundamental need in the autonomous driving industry [12, 17]. It aims to infer the 3D structure of vehicles at arbitrary resolutions in the wild, which is of great significance to many downstream tasks in autonomous driving. Despite the many 3D reconstruction methods + +![](images/874358cfe3f7daf165f03b2f783a448991beac9a618f340f6a9ce7612a90a3b7.jpg) +Figure 1. An illustration of the motivation of the proposed approach. Our approach takes multi-sweep point clouds as input and simplifies 3D vehicle reconstruction from multi-sweeps into an element-to-set feature extraction problem. In this way, we infer an optimal estimation of the 3D shape described in the abstract implicit space for 3D vehicle reconstruction in autonomous driving. + +[28, 35, 26, 39, 41, 1, 19, 4], most of them focus on image-based inputs [28, 35, 26, 39, 41], dense point cloud inputs [19, 31, 11], or their combination [1, 4, 9] and thus, cannot be directly applied to this problem. + +Recently, [12] has shown promising performance in applying implicit modeling to tackle this problem. Contrary to explicit modeling methods [32, 33, 47, 49, 43, 42, 10, 2, 38] that directly represent 3D object shape structure with points, voxels, or meshes, implicit modeling maps the 3D shape to a low-dimensional latent space and learns the projection from the latent space to a continuous function that describes the 3D shape. This presents two significant advantages: 1) the 3D shape can be stored as a low-dimensional memory-saving latent code [31, 11, 12, 6]; 2) the trained network outputs a continuous function in the 3D space which supports mesh extraction at any resolution [31]. To this end, we also choose to employ implicit modeling in our approach. + +However, previous point cloud-based implicit modeling methods [31, 11, 12] mainly focus on recovering 3D shapes from a single-view partial point cloud and fail to leverage the multi-sweep information of vehicles. As a result, when noise or annotation errors exist in an individual sweep, single-view methods usually produce low fidelity results. In real-world datasets (e.g., [36, 15]), multi-sweep + +![](images/acd7e7eb2dd647e7a79fcc94f31d1ee273b2517b306db0ad51afc76a748c7b6d.jpg) +Figure 2. The framework of the proposed MV-DeepSDF. Farthest Point Sampling (FPS) [33] is applied to the raw point clouds for preprocessing and DeepSDF [31] is employed to generate a latent code for each observation. We then extract global features from the standardized point clouds (refer to yellow block) and concatenate the global features with the latent codes as element-level representations. Next, the element-level representations are transformed into a set-level predicted latent code (refer to red block). Finally, we employ a pre-trained DeepSDF decoder [31] to project the predicted latent code to the SDF of the vehicle in 3D space and recover the 3D mesh. Note that the decoder used in the final step (refer to white trapezoid) is identical to that of DeepSDF (refer to green block). + +point clouds are usually available and contain richer shape information because of the various viewing angles offered by multiple observations [17]. Although there are some existing 3D reconstruction methods from multi-view point clouds [17, 19, 3, 34], implicit modeling with multi-sweep point clouds remains an unsolved problem. + +In this work, we propose a novel framework, dubbed MV-DeepSDF, to exploit multi-sweep point clouds and implicitly generate high-fidelity 3D reconstructions of vehicles for autonomous driving. An illustration of the motivation for our proposed approach is depicted in Figure 1. Specifically, to shed light on the importance of exploring multi-sweep point clouds for 3D vehicle reconstruction, we first analyze multi-sweep consistency and complementarity in the latent feature space. We then propose to consider the problem of shape estimation in the implicit space as an element-to-set feature extraction problem, where a set represents a collection of multi-sweeps and an element represents a sparse and partial point cloud. Next, we devise a new architecture to simultaneously extract a global feature and latent code for each element in the multi-sweep and concatenate them as element-level representations. These element-level representations are then transformed into a set-level predicted latent code with the aid of average pooling and mapping. This set-level latent code is an optimal estimation of the 3D shape described in the abstract implicit space, which we subsequently decode to a continuous SDF of the vehicle with a pre-trained DeepSDF decoder [31] and recover the 3D mesh from the SDF. The contributions of this work are threefold: + +We analyze multi-sweep consistency and complement + +tarity in the latent feature space and transform the problem of shape estimation in the implicit space into an element-to-set feature extraction problem. This simplifies 3D vehicle reconstruction from multi-sweep point clouds into an optimal estimation of the 3D shape described in the abstract implicit space. + +- We propose a novel MV-DeepSDF framework (see Figure 2) for implicit modeling with multi-sweep point clouds. A new architecture is constructed to extract the element-level representations and generate the set-level predicted latent code. +- We qualitatively and quantitatively demonstrate the superior performance of our approach over the state-of-the-art alternative methods through extensive experiments on real-world datasets [36, 15]. + +# 2. Related Work + +# 2.1. Explicit Modeling-Based 3D Reconstruction + +Conventional 3D explicit modeling can be classified into three categories, namely point-based [32, 33, 47, 49, 43], voxel-based [42, 10], and mesh-based [2, 38]. Point-based methods, such as Point Completion Network (PCN) [49], GRNet [43], and PoinTr [47], output a point cloud with limited resolution since the number of points is fixed and not suitable for generating watertight surfaces due to lack of topology description. Voxel-based methods [42, 10] describe volumes by subdividing the space into a 3D grid, but they are memory and compute intensive, leading to slow + +training and low resolution representations [31]. Mesh-based methods only generate meshes with simple topologies [40] given by a fixed reference template from the same object class and cannot guarantee watertight surfaces [22, 16]. In contrast, we propose implicit modeling with multi-sweep point clouds in a novel MV-DeepSDF framework, which estimates the optimal SDF shape representation for reconstructing 3D structures of vehicles in autonomous driving. + +# 2.2. Implicit Modeling-Based 3D Reconstruction + +Implicit modeling [27, 31, 11, 12] uses function-based decision boundaries to implicitly define surfaces for 3D representations. DeepSDF [31] is a classical approach to implicit modeling. It estimates the Signed Distance Function (SDF) of an object from a partial point cloud, where the SDF specifies whether a querying position is inside or outside the surface of the object and the distance of the querying position from the surface. There have been some improved versions [11, 12, 6, 45] of DeepSDF, but these methods only focus on 3D reconstruction from a single-view point cloud and thus, generally produce low fidelity results when noise or annotation errors exist in an individual sweep. In contrast, we propose a novel framework for implicit modeling with multi-sweep point clouds. We analyze multi-sweep consistency and complementarity in the latent feature space and propose to resolve this problem by an optimal estimation of the 3D shape described in the abstract implicit space. Moreover, other implicit modeling-based methods, such as Neural Radiance Fields (NeRF) [28], Point-NeRF [44], Direct Voxel Grid Optimization [35], NeuS [41], NEAT [26], and [1, 4, 9] exist, but they all require image input and cannot deal with only LiDAR data. + +# 2.3. Multi-View 3D Reconstruction + +3D reconstruction from multi-view point clouds can be categorized into conventional approaches [3, 34, 29] and deep learning-based approaches [17, 19, 5]. Conventional geometric approaches, such as Iterative Closest Point (ICP), TSDF [29], and [3, 34], only leverage multi-view observations geometrically, so the resulting completion is merely an aligned stack of partial point clouds and cannot produce watertight shapes unless the sensor fully loops around the object. In deep learning-based approaches, [17] proposes a weakly-supervised framework to directly learn 3D shape completion from multi-view LiDAR sweeps, but its reconstruction result is not watertight. [19] presents a shape completion framework using a multi-view depth map-based shape representation approach, while [5] designs a network to use multiple partial point clouds encoded into the latent space to estimate the optimal shape of the object. However, the output of these networks [19, 5] are point-based repre + +sentations and in contrast with continuous field functions such as SDFs [31], lack continuity in 3D space. Moreover, some methods, such as [13, 14, 46], exist for reconstructing vehicle shapes from multiple observations, but [13] relies on stereo images and motion priors to regularize the shape estimation of vehicles, [14] requires multi-view camera images to build semantic maps which contain 3D vehicle shapes, and [46] requires inputs to follow a time sequence to track and reconstruct 3D objects. In contrast, our approach simplifies 3D vehicle reconstruction from multisweep point clouds into an optimal estimation of the 3D shape described in the abstract implicit space, which supports mesh extraction at any resolution and can deal with noise and annotation errors that exist in an individual sweep. + +# 3. Methodology + +# 3.1. Preliminaries + +In this section, we introduce preliminaries regarding DeepSDF [31] since our approach utilizes its framework for extracting the latent code and decoding the continuous SDF for 3D mesh generation. Formally, when adopting the DeepSDF decoder into the shape completion task, points of partial point clouds are taken as given surface points and the SDF value is defined as the distance from the querying point to the surface of the object. Interior and exterior querying points are sampled along the normals of the surface points and the SDF value is computed for each querying point. Suppose the set of newly sampled interior and exterior points is denoted as $\mathcal{P}_{\mathcal{M}}$ , where $M$ is the number of points. Define the $m$ th point in $\mathcal{P}_{\mathcal{M}}$ as $\pmb{x}_m$ and its corresponding SDF value as $s_m$ . In the domain of DeepSDF [31], a 3D shape can be represented by a latent code $z \in \mathbb{R}^{256}$ in the latent space. The complete shape is obtained by optimizing $z$ via Maximum a Posterior estimation: + +$$ +\hat {z} = \frac {1}{\sigma^ {2}} \| z \| _ {2} ^ {2} + \underset {\boldsymbol {z}} {\arg \min } \sum_ {m = 1} ^ {M} \mathcal {L} _ {1} \left(f _ {\theta} \left(\boldsymbol {z}, \boldsymbol {x} _ {m}\right), s _ {m}\right), \tag {1} +$$ + +where $\mathcal{L}_1$ represents the clamped $\mathcal{L}_1$ distance and $\sigma$ is a regularization hyperparameter. Once the optimal latent code $\hat{\boldsymbol{z}}$ is determined, the complete 3D shape can be recovered by finding the zero-SDF-value isosurface through the DeepSDF decoder $f(\cdot)$ , which is defined as: + +$$ +\hat {s} = f _ {\theta} (\hat {\boldsymbol {z}}, \boldsymbol {x}), \tag {2} +$$ + +where $\theta$ represents the parameters of the decoder, $\pmb{x} \in \mathbb{R}^3$ denotes the 3D coordinates of the querying point, and $\hat{s}$ denotes the estimated SDF value given by $f(\cdot)$ . Here, the sign of $\hat{s}$ , either positive or negative, indicates whether the point lies on the exterior or interior of the surface, respectively. Thus, the surface of the object can be implicitly represented by the isosurface composed of points with zero SDF values. + +Despite its simplicity and efficiency, DeepSDF only takes the given surface points into consideration when generating 3D shapes (i.e., Eq. (1)). This can lead to suboptimal reconstruction results in areas not captured by the partial point clouds since DeepSDF will reconstruct arbitrarily based on prior knowledge learned during training. For instance, referencing the ground truth of Case 1 in Figure 3, the reconstruction results of DeepSDF for Cases 2, 3, and 4 only demonstrate high fidelity in areas with well-captured surface points. The missing areas are reconstructed arbitrarily. To resolve this problem, we analyze multi-sweep consistency and complementarity in the latent feature space and propose implicit modeling with multi-sweep point clouds in MV-DeepSDF. + +# 3.2. Approach Overview + +As shown in Figure 2, there are three main steps in MV-DeepSDF, namely preprocessing, optimal latent code prediction, and 3D mesh extraction. + +1) Preprocessing. First, we carry out Farthest Point Sampling (FPS) [33] to sample a fixed number of points on each raw partial point cloud since our global feature extractor requires standardized point clouds as input. For FPS, the number of centroids is set as 256. +2) Optimal Latent Code Prediction. The post-FPS point clouds are used as input into the global feature extractor (yellow block in Figure 2) to extract global features for each individual point cloud. Meanwhile, the original point clouds are used to extract latent codes for each partial point cloud through the pre-trained DeepSDF (green block in Figure 2). Then, as shown in the red block of Figure 2, the global features and latent codes are concatenated as element-level representations, followed by an average pooling operation to aggregate the information into a single instance tensor. Finally, this instance tensor is transformed into the predicted latent code by a fully-connected layer as the set-level representation. +3) 3D Mesh Extraction. The predicted latent code is converted to an SDF using a pre-trained DeepSDF decoder [31]. The isosurface composed of querying points with zero SDF values represents the surface of the instance and the implicit surface can be rasterized to a 3D mesh using Marching Cubes [24]. Since the SDF is a continuous function, it supports 3D mesh extraction at any resolution. + +# 3.3. Consistency and Complementarity Analysis + +Background. In literature [37, 50], multi-view consistency refers to the consistency of describing the same instance from different viewpoint observations and multi-view complementarity refers to the complementary information of the same instance provided by different observations. Existing methods mainly explore multi-view consistency and complementarity for 3D reconstruction with par + +![](images/d98b3d4102529c6d45a9201561ab4f13c29f0577e2ea222a69168be1c16f3a27.jpg) +Figure 3. The 3D reconstruction results of DeepSDF [31] (row 2) using different point clouds (row 1). All point clouds are sampled from the same CAD model of ShapeNetV2 [7]. Case 1 shows the complete dense point cloud used to train the DeepSDF decoder, while Cases 2, 3, and 4 show the partial point clouds. + +tial point clouds in explicit modeling [34, 3]. + +However, existing methods are not applicable for exploring multi-sweep/-view consistency and complementarity in implicit modeling because the abstract feature space operates differently than the explicit space. In implicit modeling, point clouds are expressed as low-dimensional feature vectors (a.k.a. latent vectors) in the latent feature space and the latent vectors are generated through a non-linear learning process that projects the 3D space to the feature space through a deep neural network [31, 32, 33, 49]. + +Theoretical Analysis. Despite these differences, we can still explore multi-sweep consistency and complementarity in the latent feature space for implicit modeling. Inspired by [25], consider a total of $B$ observations. The latent code for the $i$ th observation, denoted by $z_{i}$ , can be represented as: + +$$ +\boldsymbol {z} _ {i} = \boldsymbol {z} _ {i, c} + \boldsymbol {z} _ {i, s} + \boldsymbol {e} _ {i}, \tag {3} +$$ + +where $i = \{1,\dots ,B\}$ $z_{i,c}$ is the consistent component, $z_{i,s}$ is the specific component, and $e_i$ is the error component. In this work, $z_{i,c}$ and $z_{i,s}$ can be defined as follows: + +$$ +\boldsymbol {z} _ {i, c} = \boldsymbol {z} _ {i} \cap \boldsymbol {z} _ {g t} \quad \text {a n d} \quad \left(\boldsymbol {z} _ {i, s} + \boldsymbol {e} _ {i}\right) = \boldsymbol {z} _ {g t} - \boldsymbol {z} _ {i}, \tag {4} +$$ + +where $\mathbf{z}_{gt}$ is the latent code corresponding to the ground truth shape and '∩' and '−' represent the similarity and difference in information captured by the two feature vectors, respectively. Now, consider any two consistent components $\mathbf{z}_{i,c}$ and $\mathbf{z}_{j,c}$ . In the first case where $\mathbf{z}_{i,c} \cap \mathbf{z}_{j,c} = \emptyset$ , the two components contain completely different consistent information, which is complementary. In the second case where $\mathbf{z}_{i,c} \cap \mathbf{z}_{j,c} \neq \emptyset$ , but $\mathbf{z}_{i,c} \nsubseteq \mathbf{z}_{j,c}$ and $\mathbf{z}_{j,c} \nsubseteq \mathbf{z}_{i,c}$ , the two components contain some different information, which can be aggregated as complementary information to approach the ground truth. In the final case where $\mathbf{z}_{i,c} \cap \mathbf{z}_{j,c} \neq \emptyset$ , but $\mathbf{z}_{i,c} \subseteq \mathbf{z}_{j,c}$ or $\mathbf{z}_{j,c} \subseteq \mathbf{z}_{i,c}$ , either $\mathbf{z}_{i,c}$ or $\mathbf{z}_{j,c}$ contains redundant information from the other component. While redundant, this will not adversely impact complementary aggregation. Thus, to make the optimal $\hat{\mathbf{z}}$ approach the ground + +truth $z_{gt}$ , it is desired to aggregate all consistent and complementary information among all individual features: + +$$ +\hat {z} = z _ {1, c} \cup z _ {2, c} \dots \cup z _ {B, c} + p, \tag {5} +$$ + +where $\cup$ refers to the complementary aggregation of information among features and $p$ denotes the predicted information for regions not captured in the multi-sweeps (e.g., the side of the vehicle not captured by the multi-sweeps as shown in the Cases 3 and 4 of Figure 3). In summary, with implicit modeling, we can learn the optimal latent code $\hat{z}$ by aggregating consistent (Eqs. (3)-(4)) and complementary (Eq. (5)) information among multi-sweeps. + +# 3.4. Architecture Design of MV-DeepSDF + +To take advantage of multi-sweep consistency and complementarity in the latent feature space, we design a new architecture for implicit modeling. Our proposed architecture uses multi-sweep point clouds as model input and generates an optimal estimation of the 3D shape in the implicit space (a.k.a. the optimal latent code) as the output. The functionality of the network can be formulated as: + +$$ +g _ {\alpha} (\boldsymbol {Z}, \boldsymbol {P}) = \hat {\boldsymbol {z}} \rightarrow \boldsymbol {z} _ {g t}, \tag {6} +$$ + +where $g(\cdot)$ denotes the desired network with associated parameters $\alpha, Z = \{z_1, \dots, z_B\}$ denotes the set of latent codes, $B$ represents the number of observations or latent codes, $P = \{\mathcal{P}_1, \dots, \mathcal{P}_B\}$ denotes the set of multi-view point clouds, and $\hat{z} \in \mathbb{R}^{256}$ and $z_{gt} \in \mathbb{R}^{256}$ represent the estimated optimal and ground truth latent codes, respectively. Hence, the goal is converted into learning a network to make $\hat{z}$ approach $z_{gt}$ for subsequent reconstructions. To this end, we devise a new architecture to realize the functionality required by simultaneously learning global features and latent codes for generating predicted latent codes. + +Specifically, inspired by PointNet [32], a pioneering work for 3D classification and segmentation, we transform the problem of shape estimation in the implicit space into an element-to-set feature extraction problem. Given a point cloud containing a set of 3D points, where all 3D points consistently describe a single object since they all belong to the same instance, we can learn a global feature for each point cloud that aggregates complementary features from each individual 3D point. However, only learning a global feature cannot be used for 3D reconstruction, so we propose to abstract the pipeline of PointNet (see Figure 4(a)) into a generalized process (see Figure 4(b)). As shown in Figure 4(a), PointNet first computes 3D point features using a shared MLP on each 3D point and then transforms these point features into a single global feature through max pooling. Now, suppose there exists a set composed of multiple elements. The goal of the generalized pipeline is to extract a feature for the entire set by aggregating all elements. To this + +![](images/8655a99fe17b13bed1cc115fd249231c3ead10cf94e87828c2ebf5cfd65ea4e2.jpg) +Figure 4. Comparison of three pipelines. (a) The pipeline of PointNet [32]. (b) The pipeline of an abstract generalized process to extract the set feature from the elements. (c) The proposed pipeline to extract the instance feature from multi-sweep point clouds. + +end, we propose two generalized operations. As shown in Figure 4(b), we define operation 1 as the computation of the element features (e.g., the shared MLP in PointNet) and operation 2 as the transformation of the element features into a set feature (e.g., the max pooling operation in PointNet). + +Using this generalized process, we can now devise our architecture to simultaneously learn global features and latent codes for generating predicted latent codes. First, we construct a global feature extractor (see yellow block in Figure 2) for learning a global feature for each point cloud that aggregates complementary features from each individual 3D point. The architecture of this feature extractor is inspired by the PCN encoder [49], a variant of PointNet [32]. This block is a stack of four PointNet [32] encoders with 128, 256, 512, and 1024 units, respectively. Since this architecture is inspired by the PCN encoder [49] and its global feature extraction operation is applied to every individual point cloud, we name it shared PCN. Meanwhile, to exploit the implicit information of each element, we employ a pre-trained DeepSDF [31] model (as denoted by Eq. (1)) to generate a latent code for each partial point cloud. Next, we concatenate the global features and latent codes to generate the element-level representations. Then, we employ average pooling and mapping to aggregate the element-level representations into a set-level predicted latent code. As shown in Figure 4(c), operation 1 of our pipeline consists of a global feature extractor and a pre-trained DeepSDF model, while operation 2 consists of concatenation, average pooling, and mapping. This pipeline realizes a symmetric operation on unordered multi-sweep point clouds. + +# 3.5. Model Training of MV-DeepSDF + +We adopt a curriculum learning strategy for model training, which consists of two stages. + +Stage One. In stage one, we pre-train the DeepSDF decoder using watertight CAD models belonging to the car taxonomy of the ShapeNetV2 dataset [7]. The latent code $z$ + +and parameters of the decoder $\theta$ are jointly optimized as: + +$$ +\underset {\theta , \left\{\boldsymbol {z} _ {j} \right\} _ {j = 1} ^ {J}} {\arg \min } \sum_ {j = 1} ^ {J} \left(\frac {1}{\sigma^ {2}} \left\| \boldsymbol {z} _ {j} \right\| _ {2} ^ {2} + \sum_ {k = 1} ^ {K} \mathcal {L} _ {1} \left(f _ {\theta} \left(\boldsymbol {z} _ {j}, \boldsymbol {x} _ {k}\right), s _ {k}\right)\right), \tag {7} +$$ + +where $J$ represents the number of 3D shapes used for training and $K$ represents the number of points for each shape. During this stage, the decoder gains prior knowledge of vehicle shapes and once trained, the decoder remains fixed for the latent code generation step of our pipeline. Please refer to [31] for the details of the training at this step. + +Training Dataset Preparation for Stage Two. As shown in Eq. (6), ground truth latent codes, partial point clouds, and their corresponding latent codes are required for training the reconstruction network. However, real-world datasets, such as Waymo [36] and KITTI [15], do not contain ground truth shapes, so it is necessary to use a synthetic dataset [7] for generating the training data. To resolve this problem, we utilize the latent codes of the training shapes (e.g., the complete dense point cloud shown in Case 1 of Figure 3) as ground truth latent codes in the second stage of model training. As for the partial point clouds, the domain gap between training instances and in-the-wild instances directly determines the ability of our network to generalize to real-world datasets. To reduce the domain gap, we adopt PCGen [23] as our partial point cloud generation method. PCGen places a virtual LiDAR with real-world parameters (resolution and sampling pattern) around the vehicle and simulates the point cloud captured by the virtual LiDAR. This differs from the method used by DeepSDF [31], where a simulated depth camera is used as the virtual sensor instead of a LiDAR. A visual comparison of the real-world point cloud and simulated partial point clouds obtained using various methods is given in Figure 5. As shown in Figure 5, the partial point clouds of PCGen [23] are visually closer to the in-the-wild LiDAR sweeps of Waymo [36] and KITTI [15] than those of the virtual depth camera approach [31], which only raycasts evenly in the inclination and azimuth directions. Apart from this visual superiority, the advantages of generating partial point clouds with PCGen can also be observed through the improved generalization ability of our network. See experiments for further details. + +When generating training data from ShapeNetV2 [7], we randomly sample one side of the vehicle to accurately reflect the real-world scan of a LiDAR on an ego-vehicle. In this way, we produce six partial point clouds for each vehicle. The virtual LiDAR pose for each partial point cloud is generated using a set of restrictions. These restrictions are set by considering the possible relative poses of an ego vehicle's LiDAR in the coordinate system of the other vehicle. In particular, $\theta \in [0^{\circ}, 180^{\circ}]$ or $\theta \in [-180^{\circ}, 0^{\circ}]$ , $r \in [3, 15]$ , and $h \in [0.8, 1.2]$ are used, where $\theta$ represents the azimuth, + +![](images/30f16c703f4b656e8cd24191236d3e2ffc85da5d9a635d276f612e95c5a0088c.jpg) + +![](images/f4c86d858ccb74fdc389d952f3babf758bf13160c0d7362dad6fc71a34885111.jpg) + +![](images/2751cdca10a3d5ed7d1d8229aaab772a1213df621f962171f15d1a2be7fe2f44.jpg) +(c) +(d) +(e) +Figure 5. Visual comparison of in-the-wild partial point clouds and raycasted point clouds. (a) A partial point cloud from the Waymo tracking dataset [36]. (b) The raycasted point cloud generated by PCGen [23] using the LiDAR parameters of Waymo. (c) A partial point cloud from the KITTI tracking dataset [15]. (d) The raycasted point cloud generated by PCGen [23] using the LiDAR parameters of KITTI. (e) The raycasted point cloud obtained from the virtual depth camera approach used by DeepSDF [31]. + +$r$ represents the distance between the LiDAR and the vehicle, and $h$ represents the height of the LiDAR to the ground. $\theta, r,$ and $h$ describes the pose of the virtual LiDAR with respect to the frame of the other vehicle. Both $r$ and $h$ are expressed in the normalized space, where the size of the vehicle is normalized into the range $[-1, 1]$ . Finally, we generate a latent code for each partial point cloud using Eq. (1). + +Stage Two. In stage two, the network is trained to reconstruct 3D vehicles from multi-view partial point clouds and their corresponding latent codes. Consider the $c$ th vehicle instance. Let $P_{B,c}$ represent the set of partial point clouds, $Z_{B,c}$ represent the set of latent codes corresponding to the multi-view point clouds, and $z_{gt,c}$ represent the ground truth latent code acquired from stage one. Furthermore, let $g(\cdot)$ represent the function of the implicit shape prediction network (refer to yellow and red blocks in Figure 2) and $\alpha$ represent the parameters of the model. The training objective of stage two can be defined as: + +$$ +\underset {\alpha} {\arg \min } \sum_ {c = 1} ^ {C} \mathcal {L} _ {2} \left(g _ {\alpha} \left(\boldsymbol {Z} _ {B, c}, \boldsymbol {P} _ {B, c}\right), \boldsymbol {z} _ {g t, c}\right), \tag {8} +$$ + +where $C$ represents the number of instances employed for training and $\mathcal{L}_2$ is the Mean Squared Error loss. The training details are presented in Sec. 4.1. + +# 4. Experiments + +In this section, we present qualitative and quantitative results on two real-world autonomous driving datasets, namely Waymo [36] and KITTI [15]. The multi-sweep point clouds for Waymo are collected from 136 unique vehicle instances of Waymo Open Dataset's tracking data [36], while those for KITTI are extracted from 233 vehicle in + +![](images/468cb5d1e2e84e3ea597ed086246a8b1ec77fd0131991a6d33b9438fea42ba94.jpg) +Figure 6. Visual comparison with the state-of-the-art methods (DeepSDF [31], C-DeepSDF [11], MendNet [12], and AdaPoinTr [48]) on the Waymo [36] dataset. DeepSDF+MS and MendNet+MS indicate the models with multi-sweep input. + +stances of KITTI's tracking dataset [15]. Due to page limitations, experiment details and some results (e.g., the results on the synthetic dataset ShapeNetV2 [7]) are discussed in the supplementary material. + +# 4.1. Implementation Details + +Architecture Details. Our global feature extractor, named shared PCN, is a variant of the PCN encoder [49]. The embedded shared MLP layers are identical to those of PointNet [32], which are implemented using 1D convolution layers. Moreover, since DeepSDF [31] normalizes the latent codes into the range $[-1, 1]$ , we add a tanh layer after the last shared MLP to normalize the global features into the same range as the latent codes. The decoder is identical to that of DeepSDF [31]. We report results based on an implementation with Python and PyTorch, but our approach also supports implementation with MindSpore [20]. + +Training Details. In the first stage of training, we follow the same method as presented in DeepSDF [31] to train the decoder using watertight CAD models from the car taxonomy of ShapeNetV2 [7]. Once trained, the decoder is fixed and projects a 256-dimensional latent code to an SDF in 3D space. In the second stage, we train the model for 20 epochs using the Adam optimizer [21] with a learning rate of 1e-5. The batch size is set to 1, allowing the model to simultaneously see all 6 frames of the given instance at each iteration. Since both the output of the model and the supervision are 1D vectors, the loss computation is very fast. It only takes 10 minutes to train our network on a single NVIDIA GeForce RTX 2080 GPU during stage two. However, the DeepSDF decoder [31] used to prepare the training dataset for stage two through latent code generation is a more time-consuming process. + +# 4.2. Evaluation Protocol + +Metrics. Since an in-the-wild instance does not have a ground truth 3D shape, we follow [12] to evaluate the recon + +struction results. In particular, the multiple LiDAR sweeps are stacked to construct the ground truth points set $\pmb{X}$ . Moreover, we sample 30,000 points on the surface of each reconstructed mesh to generate the reconstruction points set $\pmb{Y}$ . We employ Asymmetric Chamfer Distance (ACD) [12], which is the sum of the squared distance of each ground truth point to the nearest point in the reconstructed point set, to evaluate reconstruction results on real-world datasets: + +$$ +\operatorname {A C D} \left(\boldsymbol {X}, \boldsymbol {Y}\right) = \sum_ {\boldsymbol {x} \in \boldsymbol {X}} \min _ {\boldsymbol {y} \in \boldsymbol {Y}} \| x - \boldsymbol {y} \| _ {2} ^ {2}. \tag {9} +$$ + +For ACD, a smaller value is preferred. In addition, we compute the recall of the ground truth points from the reconstructed shape, which is defined as: + +$$ +\operatorname {R e c a l l} (\boldsymbol {X}, \boldsymbol {Y}) = \frac {1}{| \boldsymbol {X} |} \sum_ {x \in \boldsymbol {X}} \left[ \min _ {y \in \boldsymbol {Y}} \| x - y \| _ {2} ^ {2} < = t \right], \tag {10} +$$ + +where the threshold $t$ is set as 0.1, following [12]. + +Competitors. We compare our approach with four state-of-the-art methods, including three implicit modeling-based methods (DeepSDF [31], C-DeepSDF [11], and MendNet [12]) and AdaPoinTr [48], which is built upon PoinTr++ [47], the winner of Multi-View Partial Point Cloud Challenge 2021 on Completion and Registration [30]. Training data for DeepSDF and C-DeepSDF are generated following the original papers, while MendNet uses PCGen [23] to generate training data. The pipeline of AdaPoinTr [48] requires online generation of partial point clouds using the virtual depth camera approach and since it is not trivial to replace this process with PCGen, AdaPoinTr is trained using the default setup without PCGen. Note that with multi-sweep point clouds, competitors generate multiple reconstruction results (one for each partial point cloud), so we compare with the best single-shot reconstruction result, which is the mesh with the minimum ACD among the multiple single-shot reconstructed meshes. Furthermore, we report the results of DeepSDF and MendNet with multi-sweep + +
Method \ MetricACDmean ↓ACDmedian ↓Recall ↑
DeepSDF [31]6.265.8193.51
DeepSDF+MS5.125.0995.57
C-DeepSDF [11]6.215.6493.98
MendNet [12]4.924.7995.39
MendNet+MS4.854.7795.76
AdaPoinTr*[48]4.794.7495.95
Ours-VDC4.764.5596.05
Ours3.362.2696.84
+ +Table 1. Comparison with the state-of-the-art methods on Waymo. ACD $\downarrow$ is multiplied by $10^{3}$ . Recall $\uparrow$ is presented as a percentage. *AdaPoinTr is trained with the default setup without PCGen on the large-scale ShapeNet-55 [47] following the original paper [48], and then fine-tuned on the car taxonomy of ShapeNetV2 in our experiments. Other methods are only trained with the car taxonomy of ShapeNetV2. + +inputs (denoted as DeepSDF+MS and MendNet+MS), in which we stack the partial point clouds of multi-sweeps into a single point cloud and perform single-shot-based reconstruction on this stacked point cloud. For our approach, in addition to the default setup which generates the training dataset using PCGen (denoted as Ours), we also adapt our approach to use training data generated by the virtual depth camera approach [31] (denoted as Ours-VDC). + +# 4.3. Results on Waymo + +The qualitative and quantitative comparisons of our approach with the state-of-the-art methods are presented in Figure 6 and Table 1, respectively. Overall, our approach achieves the best reconstruction results both qualitatively and quantitatively. Specifically, from Figure 6 and Table 1, we can see that DeepSDF [31] and C-DeepSDF [11] are sensitive to noise, resulting in low fidelity. MendNet [12] generates more stable results than DeepSDF and C-DeepSDF, but its reconstruction meshes contain some irregular holes on the surface (see sixth column of Figure 6). Although AdaPoinTr [48] outputs point clouds with good fidelity, it expresses the shape with a limited resolution and thus fails to describe continuous local details (see seventh column of Figure 6). + +Compared with vanilla DeepSDF and MendNet, DeepSDF+MS and MendNet+MS yield messier surfaces/structures (see fourth and eighth columns of Figure 6), despite their better metric scores. This shows that even though transforming all partial point clouds into a single frame does benefit information aggregation, it also accumulates noise and annotation errors in the process. Hence, due to noise in real-world data, it is not practical to geometrically stack multi-sweep point clouds and directly perform single-shot-based reconstruction. In comparison, our approach generates smooth watertight shapes (see last two columns of Figure 6) with high fidelity (see Table 1). Furthermore, Ours outperforms Ours-VDC, which indicates + +
Method \ MetricACDmean ↓ACDmedian ↓Recall ↑
DeepSDF [31]6.816.1780.65
DeepSDF+MS6.115.8382.73
C-DeepSDF [11]6.735.9980.77
MendNet [12]5.945.6483.84
MendNet+MS5.835.6184.26
AdaPoinTr [48]5.895.6784.20
Ours-VDC5.755.2484.39
Ours4.273.0185.88
+ +Table 2. Comparison with the state-of-the-art methods on KITTI. ACD $\downarrow$ is multiplied by ${10}^{3}$ . Recall $\uparrow$ is presented as a percentage. + +that using PCGen to prepare training partial point clouds (refer to Figure 5) reduces the domain gap between training and in-the-wild instances. + +# 4.4. Results on KITTI + +The qualitative and quantitative comparisons of our approach against the state-of-the-art methods are presented in Figure 7 and Table 2, respectively. From these results, we can also observe the superior performance of our approach over the state-of-the-art competitors. Specifically, qualitatively, as shown in Figure 7, our approaches (Ours and Ours-VDC) are more robust to noise when compared to DeepSDF [31], DeepSDF+MS, and C-DeepSDF [11] and generate smoother, watertight surfaces compared to MendNet [12], AdaPoinTr [48], and MendNet+MS. Quantitatively, as shown in Table 2, Ours yields the best ACD and Recall results, while Ours-VDC performs the second best. + +# 4.5. Ablation Study + +To verify the effectiveness of the main components of our approach, we carry out a series of experiments on Waymo [36] as shown in Table 3. The first row of Table 3 refers to the baseline model of our approach, which is a shared PCN encoder (Enc.) (yellow block in Figure 2) followed by an average pooling layer (Avg.). This architecture is similar to that of MendNet [12], which adds two stacked PointNet encoders [32] to the DeepSDF decoder. In the second row, we directly use bitwise multiplication to merge the global features $(\mathrm{B} \times 256$ , instead of $\mathrm{B} \times 1024)$ and the latent codes $(\mathrm{B} \times 256)$ . However, this results in obvious performance degradation, which shows that directly merging the global features and latent codes obtained from multi-sweep information does not bring improvement to our baseline model. In comparison, in the third row, we add our proposed components, namely the input of latent codes (Dep.), concatenation (Con.), and mapping (Map.), to the baseline model, but with max pooling. This brings significant performance improvement compared to the first and second rows. Then, in the last row, we further replace max pooling with average pooling, which includes all proposed components of this work. This yields the best results. + +![](images/18f87ca6b80bdaed4bb7c8ec381d474b6a20ba3ca66c6d70847942fa6993c4db.jpg) +Figure 7. Visual comparison with the state-of-the-art methods (DeepSDF [31], C-DeepSDF [11], MendNet [12], and AdaPoinTr [48]) on the KITTI [15] dataset. DeepSDF+MS and MendNet+MS indicate the models with multi-sweep input. + +
Operation 1Operation 2Metric
Enc.Dep.Mer.PoolMap.ACD ↓Recall ↑
✓Avg.4.8995.50
✓✓Mul.Avg.7.3384.93
✓✓Con.Max.✓4.3596.61
✓✓Con.Avg.✓3.3696.84
+ +Table 3. The ablation study of the proposed framework. Refer to Figure 4(b) to see the definitions of operations 1 and 2. Enc.: the shared PCN encoder; Dep.: latent code generation through DeepSDF as input; Mer.: the operation to merge global features and latent codes; Map.: the mapping conducted by the fully-connected layer; Con.: the concatenation; Mul.: the bitwise multiplication; Avg.: average pooling; Max.: max pooling. ACD $\downarrow$ is multiplied by $10^{3}$ . Recall $\uparrow$ is presented as a percentage. + +# 4.6. Extension to Other Taxonomies + +It is straightforward to extend the proposed shape completion framework to other taxonomies. Suppose that we want to extend MV-DeepSDF to perform shape completion on sofas. First, a new DeepSDF decoder [31] needs to be pre-trained using watertight CAD models from the sofa taxonomy of ShapeNetV2 [7] or another synthetic dataset. Then, PCGen [23] or another sampling technique (e.g., the approaches proposed in [31, 47]) can be used to generate partial point clouds for each sofa instance. These partial point clouds are then passed into the pre-trained DeepSDF decoder [31] to produce their corresponding latent codes. Finally, the partial point clouds and latent codes can be used together to train MV-DeepSDF. Following the pipeline above, we evaluate on indoor sofas of ShapeNetV2 and outdoor cyclists of Waymo and show that our method is versatile and extendible to other taxonomies (see Figure 8). + +While existing datasets, such as ScanNet [8] and Semantic3D [18], provide real-world point cloud data for many taxonomies, the availability of tracking data for multisweep scans is still fairly limited to the autonomous driving industry. Hence, it is necessary to first obtain the corresponding multi-sweep tracking labels for the desired class + +![](images/c4cb8880ef53068dcf8ed84513b605e3aac76208b6df9007a5488ed48d7d2f16.jpg) +DeepSDF + +![](images/a875898f1b839db6763c802e3a3a8a78f181d0a0411b55198939f8d323fdada3.jpg) +Ours + +![](images/7e5ebe97fcaccc30098413a0ea2f79925b9794c31ed7eb0f6025987cd27b1331.jpg) +DeepSDF +Figure 8. Visual comparison of DeepSDF and MV-DeepSDF on the indoor sofa of ShapeNetV2 and the outdoor cyclist of Waymo. + +![](images/08de1cbce990fce5abfa5b29c3e4924de05892e5dee43379958883d6205407c4.jpg) +Ours + +when choosing to adopt MV-DeepSDF on a new taxonomy. + +# 5. Conclusion + +In this work, we propose a new MV-DeepSDF framework to facilitate implicit modeling with multi-sweep point clouds for autonomous driving. The main idea is to abstract 3D vehicle reconstruction from multi-sweeps into an element-to-set feature extraction problem. Namely, we consider the multi-sweeps of a vehicle as elements composing a set and infer the set feature, which is an optimal estimation of the 3D shape described in the abstract implicit space. In particular, we present a theoretical analysis of multi-sweep consistency and complementarity in the latent feature space. Guided by this analysis, we design a new architecture to optimally estimate the Signed Distance Function shape of a vehicle from its in-the-wild multi-sweep point clouds. Qualitative and quantitative evaluations on both real-world and synthetic datasets show the superiority of our approach over the state-of-the-art methods. + +Limitation. Despite promising results, our approach still relies on a synthetic 3D dataset to gain prior knowledge of 3D shapes for reconstruction. Exploring reconstruction by learning directly from real data is worthy of further study. + +# Acknowledgments + +The authors gratefully acknowledge the support of MindSpore, CANN, and Ascend AI Processor. The authors would also like to thank Andrew Yang and Hunter Schofield for their assistance. + +# References + +[1] Dejan Azinović, Ricardo Martin-Brualla, Dan B Goldman, Matthias Nießner, and Justus Thies. Neural rgb-d surface reconstruction. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6290-6301, 2022. +[2] Heli Ben-Hamu, Haggai Maron, Itay Kezurer, Gal Avineri, and Yaron Lipman. Multi-chart generative surface modeling. ACM Transactions on Graphics, 37(6):1-15, 2018. +[3] Paul J Besl and Neil D McKay. Method for registration of 3-d shapes. In Sensor fusion IV: control paradigms and data structures, volume 1611, pages 586-606. Spie, 1992. +[4] Hongrui Cai, Wanquan Feng, Xuetao Feng, Yan Wang, and Juyong Zhang. Neural surface reconstruction of dynamic scenes with monocular rgb-d camera. In Proc. of Conference on Neural Information Processing Systems, 2022. +[5] Yingjie Cai, Kwan-Yee Lin, Chao Zhang, Qiang Wang, Xiaogang Wang, and Hongsheng Li. Learning a structured latent space for unsupervised point cloud completion. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5543-5553, 2022. +[6] Rohan Chabra, Jan E Lenssen, Eddy Ilg, Tanner Schmidt, Julian Straub, Steven Lovegrove, and Richard Newcombe. Deep local shapes: Learning local sdf priors for detailed 3d reconstruction. In Proc. of European Conference on Computer Vision, pages 608-625. Springer, 2020. +[7] Angel X Chang, Thomas Funkhouser, Leonidas Guibas, Pat Hanrahan, Qixing Huang, Zimo Li, Silvio Savarese, Manolis Savva, Shuran Song, Hao Su, et al. Shapenet: An information-rich 3d model repository. arXiv preprint arXiv:1512.03012, 2015. +[8] Angela Dai, Angel X Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 5828-5839, 2017. +[9] Angela Dai, Christian Diller, and Matthias Nießner. Sg-nn: Sparse generative neural networks for self-supervised scene completion of rgb-d scans. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 849–858, 2020. +[10] Angela Dai, Charles Ruizhongtai Qi, and Matthias Nießner. Shape completion using 3d-encoder-predictor cnns and shape synthesis. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 5868-5877, 2017. +[11] Yueqi Duan, Haidong Zhu, He Wang, Li Yi, Ram Nevata, and Leonidas J Guibas. Curriculum deepsdf. In Proc. of European Conference on Computer Vision, pages 51-67. Springer, 2020. +[12] Shivam Duggal, Zihao Wang, Wei-Chiu Ma, Sivabalan Manivasagam, Justin Liang, Shenlong Wang, and Raquel Urtasun. Mending neural implicit modeling for 3d vehicle reconstruction in the wild. In Proc. of IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1900-1909, 2022. + +[13] Francis Engelmann, Jörg Stuckler, and Bastian Leibe. Samp: shape and motion priors for 4d vehicle reconstruction. In Proc. of IEEE Winter Conference on Applications of Computer Vision, pages 400-408. IEEE, 2017. +[14] Qiaojun Feng, Yue Meng, Mo Shan, and Nikolay Atanasov. Localization and mapping using instance-specific mesh models. In Proc. of IEEE/RSJ International Conference on Intelligent Robots and Systems, pages 4985-4991. IEEE, 2019. +[15] Andreas Geiger, Philip Lenz, Christoph Stiller, and Raquel Urtasun. Vision meets robotics: The kitti dataset. The International Journal of Robotics Research, 32(11):1231-1237, 2013. +[16] Thibault Groueix, Matthew Fisher, Vladimir G Kim, Bryan C Russell, and Mathieu Aubry. A papier-mâché approach to learning 3d surface generation. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 216-224, 2018. +[17] Jiayuan Gu, Wei-Chiu Ma, Sivabalan Manivasagam, Wenyuan Zeng, Zihao Wang, Yuwen Xiong, Hao Su, and Raquel Urtasun. Weakly-supervised 3d shape completion in the wild. In Proc. of European Conference on Computer Vision, pages 283-299. Springer, 2020. +[18] Timo Hackel, Nikolay Savinov, Lubor Ladicky, Jan D Wegner, Konrad Schindler, and Marc Pollefeys. Semantic3d. net: A new large-scale point cloud classification benchmark. arXiv preprint arXiv:1704.03847, 2017. +[19] Tao Hu, Zhizhong Han, Abhinav Shrivastava, and Matthias Zwicker. Render4completion: Synthesizing multi-view depth maps for 3d shape completion. In Proc. of the IEEE/CVF International Conference on Computer Vision Workshops, pages 0–0, 2019. +[20] Huawei. Mindspace. https://www.mindspore.cn/, 2020. +[21] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. In Proc. of the International Conference on Learning Representations (Poster), 2015. +[22] Chen Kong, Chen-Hsuan Lin, and Simon Lucey. Using locally corresponding cad models for dense 3d reconstructions from a single image. In Proc. the IEEE conference on computer vision and pattern recognition, pages 4857-4865, 2017. +[23] Chenqi Li, Yuan Ren, and Bingbing Liu. Pcgen: Point cloud generator for lidar simulation. In Proc. of International Conference on Robotics and Automation, 2023. +[24] William E Lorensen and Harvey E Cline. Marching cubes: A high resolution 3d surface construction algorithm. ACM siggraph computer graphics, 21(4):163-169, 1987. +[25] Shirui Luo, Changqing Zhang, Wei Zhang, and Xiaochun Cao. Consistent and specific multi-view subspace clustering. In Proc. of the AAAI conference on artificial intelligence, volume 32, 2018. +[26] Xiaoxu Meng, Weikai Chen, and Bo Yang. Neat: Learning neural implicit surfaces with arbitrary topologies from multi-view images. Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, June 2023. +[27] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: + +Learning 3d reconstruction in function space. In Proc. of IEEE Conf. on Computer Vision and Pattern Recognition, 2019. +[28] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021. +[29] Richard A Newcombe, Shahram Izadi, Otmar Hilliges, David Molyneaux, David Kim, Andrew J Davison, Pushmeet Kohi, Jamie Shotton, Steve Hodges, and Andrew Fitzgibbon. Kinectfusion: Real-time dense surface mapping and tracking. In Proc. IEEE international symposium on mixed and augmented reality, pages 127-136. Ieee, 2011. +[30] Liang Pan, Tong Wu, Zhongang Cai, Ziwei Liu, Xumin Yu, Yongming Rao, Jiwen Lu, Jie Zhou, Mingye Xu, Xiaoyuan Luo, et al. Multi-view partial (mvp) point cloud challenge 2021 on completion and registration: Methods and results. arXiv preprint arXiv:2112.12053, 2021. +[31] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. Deepsdf: Learning continuous signed distance functions for shape representation. In Proc. of the IEEE/CVF conference on computer vision and pattern recognition, pages 165-174, 2019. +[32] Charles R Qi, Hao Su, Kaichun Mo, and Leonidas J Guibas. Pointnet: Deep learning on point sets for 3d classification and segmentation. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 652-660, 2017. +[33] Charles Ruizhongtai Qi, Li Yi, Hao Su, and Leonidas J Guibas. Pointnet++: Deep hierarchical feature learning on point sets in a metric space. Advances in neural information processing systems, 30, 2017. +[34] Radu Bogdan Rusu, Nico Blodow, and Michael Beetz. Fast point feature histograms (fpfh) for 3d registration. In Proc. of IEEE international conference on robotics and automation, pages 3212-3217. IEEE, 2009. +[35] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5459-5469, 2022. +[36] Pei Sun, Henrik Kretzschmar, Xerxes Dotiwalla, Aurelien Chouard, Vijaysai Patnaik, Paul Tsui, James Guo, Yin Zhou, Yuning Chai, Benjamin Caine, et al. Scalability in perception for autonomous driving: Waymo open dataset. In Proc. of the IEEE/CVF conference on computer vision and pattern recognition, pages 2446-2454, 2020. +[37] Shubham Tulsiani, Alexei A Efros, and Jitendra Malik. Multi-view consistency as supervisory signal for learning shape and pose prediction. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 2897-2905, 2018. +[38] Nitika Verma, Edmond Boyer, and Jakob Verbeek. Feastnet: Feature-steered graph convolutions for 3d shape analysis. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 2598-2606, 2018. +[39] Dan Wang, Xinrui Cui, Xun Chen, Zhengxia Zou, Tianyang Shi, Septimiu Salcudean, Z Jane Wang, and Rabab Ward. + +Multi-view 3d reconstruction with transformers. In Proc. of the IEEE/CVF International Conference on Computer Vision, pages 5722-5731, 2021. +[40] Nanyang Wang, Yinda Zhang, Zhuwen Li, Yanwei Fu, Wei Liu, and Yu-Gang Jiang. Pixel2mesh: Generating 3d mesh models from single rgb images. In Proc. of the European conference on computer vision, pages 52-67, 2018. +[41] Peng Wang, Lingjie Liu, Yuan Liu, Christian Theobalt, Taku Komura, and Wenping Wang. Neus: Learning neural implicit surfaces by volume rendering for multi-view reconstruction. arXiv preprint arXiv:2106.10689, 2021. +[42] Xiaogang Wang, Marcelo H Ang, and Gim Hee Lee. Voxel-based network for shape completion by leveraging edge generation. In Proc. of the IEEE/CVF international conference on computer vision, pages 13189-13198, 2021. +[43] Haozhe Xie, Hongxun Yao, Shangchen Zhou, Jiageng Mao, Shengping Zhang, and Wenxiu Sun. Grnet: Gridding residual network for dense point cloud completion. In Proc. of the European conference on computer vision, pages 365-381. Springer, 2020. +[44] Qiangeng Xu, Zexiang Xu, Julien Philip, Sai Bi, Zhixin Shu, Kalyan Sunkavalli, and Ulrich Neumann. Point-nerf: Point-based neural radiance fields. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5438-5448, 2022. +[45] Jianglong Ye, Yuntao Chen, Naiyan Wang, and Xiaolong Wang. Gifs: Neural implicit function for general shape representation. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12829-12839, 2022. +[46] Jianglong Ye, Yuntao Chen, Naiyan Wang, and Xiaolong Wang. Online adaptation for implicit object tracking and shape reconstruction in the wild. IEEE Robotics and Automation Letters, 7(4):8909-8916, 2022. +[47] Xumin Yu, Yongming Rao, Ziyi Wang, Zuyan Liu, Jiwen Lu, and Jie Zhou. Pointr: Diverse point cloud completion with geometry-aware transformers. In Proc. of the IEEE/CVF international conference on computer vision, pages 12498-12507, 2021. +[48] Xumin Yu, Yongming Rao, Ziyi Wang, Jiwen Lu, and Jie Zhou. Adapointr: Diverse point cloud completion with adaptive geometry-aware transformers. arXiv preprint arXiv:2301.04545, 2023. +[49] Wentao Yuan, Tejas Khot, David Held, Christoph Mertz, and Martial Hebert. Pcn: Point completion network. In Proc. of International Conference on 3D Vision, pages 728-737, 2018. +[50] Changqing Zhang, Zongbo Han, Huazhu Fu, Joey Tianyi Zhou, Qinghua Hu, et al. Cpm-nets: Cross partial multiview networks. Advances in Neural Information Processing Systems, 32, 2019. \ No newline at end of file diff --git a/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/images.zip b/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..d8fc540a92026992053a4844ca04bb5b017da157 --- /dev/null +++ b/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:22361ba422e6693aa7ac28d5d70267b234da36cc47e8a3cbcb56f0031a903fe4 +size 521528 diff --git a/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/layout.json b/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..9c3031a89b8a7c3c9106819808e92a3c4b56e8aa --- /dev/null +++ b/2023/MV-DeepSDF_ Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving/layout.json @@ -0,0 +1,9049 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 96, + 103, + 501, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 96, + 103, + 501, + 140 + ], + "spans": [ + { + "bbox": [ + 96, + 103, + 501, + 140 + ], + "type": "text", + "content": "MV-DeepSDF: Implicit Modeling with Multi-Sweep Point Clouds for 3D Vehicle Reconstruction in Autonomous Driving" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "spans": [ + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "text", + "content": "Yibo Liu" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "inline_equation", + "content": "^{1,2}" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "text", + "content": ", Kelly Zhu" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "inline_equation", + "content": "^{1,3}" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "text", + "content": ", Guile Wu" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "text", + "content": ", Yuan Ren" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "text", + "content": ", Bingbing Liu" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "text", + "content": ", Yang Liu" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "text", + "content": ", Jinjun Shan" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "text", + "content": "Huawei Noah's Ark Lab, " + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "text", + "content": "York University, " + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 81, + 160, + 512, + 190 + ], + "type": "text", + "content": "University of Toronto" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 141, + 191, + 451, + 217 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 141, + 191, + 451, + 217 + ], + "spans": [ + { + "bbox": [ + 141, + 191, + 451, + 217 + ], + "type": "text", + "content": "{yorklyb, jjshan}@yorku.ca, kellyk.zhu@mail.utoronto.ca \n{guile.wu, yuan.ren3, liu.bingbing, yang.liu9}@huawei.com" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 244, + 192, + 258 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 244, + 192, + 258 + ], + "spans": [ + { + "bbox": [ + 143, + 244, + 192, + 258 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 271, + 290, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 271, + 290, + 594 + ], + "spans": [ + { + "bbox": [ + 47, + 271, + 290, + 594 + ], + "type": "text", + "content": "Reconstructing 3D vehicles from noisy and sparse partial point clouds is of great significance to autonomous driving. Most existing 3D reconstruction methods cannot be directly applied to this problem because they are elaborately designed to deal with dense inputs with trivial noise. In this work, we propose a novel framework, dubbed MV-DeepSDF, which estimates the optimal Signed Distance Function (SDF) shape representation from multisweep point clouds to reconstruct vehicles in the wild. Although there have been some SDF-based implicit modeling methods, they only focus on single-view-based reconstruction, resulting in low fidelity. In contrast, we first analyze multi-sweep consistency and complementarity in the latent feature space and propose to transform the implicit space shape estimation problem into an element-to-set feature extraction problem. Then, we devise a new architecture to extract individual element-level representations and aggregate them to generate a set-level predicted latent code. This set-level latent code is an expression of the optimal 3D shape in the implicit space, and can be subsequently decoded to a continuous SDF of the vehicle. In this way, our approach learns consistent and complementary information among multi-sweeps for 3D vehicle reconstruction. We conduct thorough experiments on two real-world autonomous driving datasets (Waymo and KITTI) to demonstrate the superiority of our approach over state-of-the-art alternative methods both qualitatively and quantitatively." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 620, + 128, + 632 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 620, + 128, + 632 + ], + "spans": [ + { + "bbox": [ + 47, + 620, + 128, + 632 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "type": "text", + "content": "3D vehicle reconstruction from sparse and partial point clouds is a fundamental need in the autonomous driving industry [12, 17]. It aims to infer the 3D structure of vehicles at arbitrary resolutions in the wild, which is of great significance to many downstream tasks in autonomous driving. Despite the many 3D reconstruction methods" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 309, + 244, + 547, + 329 + ], + "blocks": [ + { + "bbox": [ + 309, + 244, + 547, + 329 + ], + "lines": [ + { + "bbox": [ + 309, + 244, + 547, + 329 + ], + "spans": [ + { + "bbox": [ + 309, + 244, + 547, + 329 + ], + "type": "image", + "image_path": "874358cfe3f7daf165f03b2f783a448991beac9a618f340f6a9ce7612a90a3b7.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 333, + 547, + 400 + ], + "lines": [ + { + "bbox": [ + 304, + 333, + 547, + 400 + ], + "spans": [ + { + "bbox": [ + 304, + 333, + 547, + 400 + ], + "type": "text", + "content": "Figure 1. An illustration of the motivation of the proposed approach. Our approach takes multi-sweep point clouds as input and simplifies 3D vehicle reconstruction from multi-sweeps into an element-to-set feature extraction problem. In this way, we infer an optimal estimation of the 3D shape described in the abstract implicit space for 3D vehicle reconstruction in autonomous driving." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 422, + 547, + 471 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 422, + 547, + 471 + ], + "spans": [ + { + "bbox": [ + 304, + 422, + 547, + 471 + ], + "type": "text", + "content": "[28, 35, 26, 39, 41, 1, 19, 4], most of them focus on image-based inputs [28, 35, 26, 39, 41], dense point cloud inputs [19, 31, 11], or their combination [1, 4, 9] and thus, cannot be directly applied to this problem." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 472, + 548, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 472, + 548, + 628 + ], + "spans": [ + { + "bbox": [ + 304, + 472, + 548, + 628 + ], + "type": "text", + "content": "Recently, [12] has shown promising performance in applying implicit modeling to tackle this problem. Contrary to explicit modeling methods [32, 33, 47, 49, 43, 42, 10, 2, 38] that directly represent 3D object shape structure with points, voxels, or meshes, implicit modeling maps the 3D shape to a low-dimensional latent space and learns the projection from the latent space to a continuous function that describes the 3D shape. This presents two significant advantages: 1) the 3D shape can be stored as a low-dimensional memory-saving latent code [31, 11, 12, 6]; 2) the trained network outputs a continuous function in the 3D space which supports mesh extraction at any resolution [31]. To this end, we also choose to employ implicit modeling in our approach." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "type": "text", + "content": "However, previous point cloud-based implicit modeling methods [31, 11, 12] mainly focus on recovering 3D shapes from a single-view partial point cloud and fail to leverage the multi-sweep information of vehicles. As a result, when noise or annotation errors exist in an individual sweep, single-view methods usually produce low fidelity results. In real-world datasets (e.g., [36, 15]), multi-sweep" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8306" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 48, + 69, + 547, + 248 + ], + "blocks": [ + { + "bbox": [ + 48, + 69, + 547, + 248 + ], + "lines": [ + { + "bbox": [ + 48, + 69, + 547, + 248 + ], + "spans": [ + { + "bbox": [ + 48, + 69, + 547, + 248 + ], + "type": "image", + "image_path": "acd7e7eb2dd647e7a79fcc94f31d1ee273b2517b306db0ad51afc76a748c7b6d.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 251, + 547, + 319 + ], + "lines": [ + { + "bbox": [ + 46, + 251, + 547, + 319 + ], + "spans": [ + { + "bbox": [ + 46, + 251, + 547, + 319 + ], + "type": "text", + "content": "Figure 2. The framework of the proposed MV-DeepSDF. Farthest Point Sampling (FPS) [33] is applied to the raw point clouds for preprocessing and DeepSDF [31] is employed to generate a latent code for each observation. We then extract global features from the standardized point clouds (refer to yellow block) and concatenate the global features with the latent codes as element-level representations. Next, the element-level representations are transformed into a set-level predicted latent code (refer to red block). Finally, we employ a pre-trained DeepSDF decoder [31] to project the predicted latent code to the SDF of the vehicle in 3D space and recover the 3D mesh. Note that the decoder used in the final step (refer to white trapezoid) is identical to that of DeepSDF (refer to green block)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 338, + 287, + 409 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 338, + 287, + 409 + ], + "spans": [ + { + "bbox": [ + 46, + 338, + 287, + 409 + ], + "type": "text", + "content": "point clouds are usually available and contain richer shape information because of the various viewing angles offered by multiple observations [17]. Although there are some existing 3D reconstruction methods from multi-view point clouds [17, 19, 3, 34], implicit modeling with multi-sweep point clouds remains an unsolved problem." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 410, + 288, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 410, + 288, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 410, + 288, + 696 + ], + "type": "text", + "content": "In this work, we propose a novel framework, dubbed MV-DeepSDF, to exploit multi-sweep point clouds and implicitly generate high-fidelity 3D reconstructions of vehicles for autonomous driving. An illustration of the motivation for our proposed approach is depicted in Figure 1. Specifically, to shed light on the importance of exploring multi-sweep point clouds for 3D vehicle reconstruction, we first analyze multi-sweep consistency and complementarity in the latent feature space. We then propose to consider the problem of shape estimation in the implicit space as an element-to-set feature extraction problem, where a set represents a collection of multi-sweeps and an element represents a sparse and partial point cloud. Next, we devise a new architecture to simultaneously extract a global feature and latent code for each element in the multi-sweep and concatenate them as element-level representations. These element-level representations are then transformed into a set-level predicted latent code with the aid of average pooling and mapping. This set-level latent code is an optimal estimation of the 3D shape described in the abstract implicit space, which we subsequently decode to a continuous SDF of the vehicle with a pre-trained DeepSDF decoder [31] and recover the 3D mesh from the SDF. The contributions of this work are threefold:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 57, + 701, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 701, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 57, + 701, + 288, + 714 + ], + "type": "text", + "content": "We analyze multi-sweep consistency and complement" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 324, + 338, + 545, + 410 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 324, + 338, + 545, + 410 + ], + "spans": [ + { + "bbox": [ + 324, + 338, + 545, + 410 + ], + "type": "text", + "content": "tarity in the latent feature space and transform the problem of shape estimation in the implicit space into an element-to-set feature extraction problem. This simplifies 3D vehicle reconstruction from multi-sweep point clouds into an optimal estimation of the 3D shape described in the abstract implicit space." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 315, + 421, + 547, + 540 + ], + "type": "list", + "angle": 0, + "index": 8, + "blocks": [ + { + "bbox": [ + 315, + 421, + 545, + 481 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 421, + 545, + 481 + ], + "spans": [ + { + "bbox": [ + 315, + 421, + 545, + 481 + ], + "type": "text", + "content": "- We propose a novel MV-DeepSDF framework (see Figure 2) for implicit modeling with multi-sweep point clouds. A new architecture is constructed to extract the element-level representations and generate the set-level predicted latent code." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 315, + 492, + 547, + 540 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 492, + 547, + 540 + ], + "spans": [ + { + "bbox": [ + 315, + 492, + 547, + 540 + ], + "type": "text", + "content": "- We qualitatively and quantitatively demonstrate the superior performance of our approach over the state-of-the-art alternative methods through extensive experiments on real-world datasets [36, 15]." + } + ] + } + ], + "index": 7 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 554, + 392, + 566 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 554, + 392, + 566 + ], + "spans": [ + { + "bbox": [ + 306, + 554, + 392, + 566 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 574, + 534, + 587 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 574, + 534, + 587 + ], + "spans": [ + { + "bbox": [ + 306, + 574, + 534, + 587 + ], + "type": "text", + "content": "2.1. Explicit Modeling-Based 3D Reconstruction" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "type": "text", + "content": "Conventional 3D explicit modeling can be classified into three categories, namely point-based [32, 33, 47, 49, 43], voxel-based [42, 10], and mesh-based [2, 38]. Point-based methods, such as Point Completion Network (PCN) [49], GRNet [43], and PoinTr [47], output a point cloud with limited resolution since the number of points is fixed and not suitable for generating watertight surfaces due to lack of topology description. Voxel-based methods [42, 10] describe volumes by subdividing the space into a 3D grid, but they are memory and compute intensive, leading to slow" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8307" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 180 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 180 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 180 + ], + "type": "text", + "content": "training and low resolution representations [31]. Mesh-based methods only generate meshes with simple topologies [40] given by a fixed reference template from the same object class and cannot guarantee watertight surfaces [22, 16]. In contrast, we propose implicit modeling with multi-sweep point clouds in a novel MV-DeepSDF framework, which estimates the optimal SDF shape representation for reconstructing 3D structures of vehicles in autonomous driving." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 189, + 277, + 202 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 189, + 277, + 202 + ], + "spans": [ + { + "bbox": [ + 47, + 189, + 277, + 202 + ], + "type": "text", + "content": "2.2. Implicit Modeling-Based 3D Reconstruction" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 207, + 289, + 483 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 207, + 289, + 483 + ], + "spans": [ + { + "bbox": [ + 46, + 207, + 289, + 483 + ], + "type": "text", + "content": "Implicit modeling [27, 31, 11, 12] uses function-based decision boundaries to implicitly define surfaces for 3D representations. DeepSDF [31] is a classical approach to implicit modeling. It estimates the Signed Distance Function (SDF) of an object from a partial point cloud, where the SDF specifies whether a querying position is inside or outside the surface of the object and the distance of the querying position from the surface. There have been some improved versions [11, 12, 6, 45] of DeepSDF, but these methods only focus on 3D reconstruction from a single-view point cloud and thus, generally produce low fidelity results when noise or annotation errors exist in an individual sweep. In contrast, we propose a novel framework for implicit modeling with multi-sweep point clouds. We analyze multi-sweep consistency and complementarity in the latent feature space and propose to resolve this problem by an optimal estimation of the 3D shape described in the abstract implicit space. Moreover, other implicit modeling-based methods, such as Neural Radiance Fields (NeRF) [28], Point-NeRF [44], Direct Voxel Grid Optimization [35], NeuS [41], NEAT [26], and [1, 4, 9] exist, but they all require image input and cannot deal with only LiDAR data." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 491, + 214, + 504 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 491, + 214, + 504 + ], + "spans": [ + { + "bbox": [ + 47, + 491, + 214, + 504 + ], + "type": "text", + "content": "2.3. Multi-View 3D Reconstruction" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 510, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 510, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 510, + 289, + 715 + ], + "type": "text", + "content": "3D reconstruction from multi-view point clouds can be categorized into conventional approaches [3, 34, 29] and deep learning-based approaches [17, 19, 5]. Conventional geometric approaches, such as Iterative Closest Point (ICP), TSDF [29], and [3, 34], only leverage multi-view observations geometrically, so the resulting completion is merely an aligned stack of partial point clouds and cannot produce watertight shapes unless the sensor fully loops around the object. In deep learning-based approaches, [17] proposes a weakly-supervised framework to directly learn 3D shape completion from multi-view LiDAR sweeps, but its reconstruction result is not watertight. [19] presents a shape completion framework using a multi-view depth map-based shape representation approach, while [5] designs a network to use multiple partial point clouds encoded into the latent space to estimate the optimal shape of the object. However, the output of these networks [19, 5] are point-based repre" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "text", + "content": "sentations and in contrast with continuous field functions such as SDFs [31], lack continuity in 3D space. Moreover, some methods, such as [13, 14, 46], exist for reconstructing vehicle shapes from multiple observations, but [13] relies on stereo images and motion priors to regularize the shape estimation of vehicles, [14] requires multi-view camera images to build semantic maps which contain 3D vehicle shapes, and [46] requires inputs to follow a time sequence to track and reconstruct 3D objects. In contrast, our approach simplifies 3D vehicle reconstruction from multisweep point clouds into an optimal estimation of the 3D shape described in the abstract implicit space, which supports mesh extraction at any resolution and can deal with noise and annotation errors that exist in an individual sweep." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 251, + 389, + 264 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 251, + 389, + 264 + ], + "spans": [ + { + "bbox": [ + 306, + 251, + 389, + 264 + ], + "type": "text", + "content": "3. Methodology" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 270, + 392, + 281 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 270, + 392, + 281 + ], + "spans": [ + { + "bbox": [ + 306, + 270, + 392, + 281 + ], + "type": "text", + "content": "3.1. Preliminaries" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "spans": [ + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "text", + "content": "In this section, we introduce preliminaries regarding DeepSDF [31] since our approach utilizes its framework for extracting the latent code and decoding the continuous SDF for 3D mesh generation. Formally, when adopting the DeepSDF decoder into the shape completion task, points of partial point clouds are taken as given surface points and the SDF value is defined as the distance from the querying point to the surface of the object. Interior and exterior querying points are sampled along the normals of the surface points and the SDF value is computed for each querying point. Suppose the set of newly sampled interior and exterior points is denoted as " + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "inline_equation", + "content": "\\mathcal{P}_{\\mathcal{M}}" + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "text", + "content": " is the number of points. Define the " + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "text", + "content": "th point in " + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "inline_equation", + "content": "\\mathcal{P}_{\\mathcal{M}}" + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "inline_equation", + "content": "\\pmb{x}_m" + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "text", + "content": " and its corresponding SDF value as " + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "inline_equation", + "content": "s_m" + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "text", + "content": ". In the domain of DeepSDF [31], a 3D shape can be represented by a latent code " + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "inline_equation", + "content": "z \\in \\mathbb{R}^{256}" + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "text", + "content": " in the latent space. The complete shape is obtained by optimizing " + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 304, + 288, + 547, + 492 + ], + "type": "text", + "content": " via Maximum a Posterior estimation:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 315, + 500, + 545, + 532 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 500, + 545, + 532 + ], + "spans": [ + { + "bbox": [ + 315, + 500, + 545, + 532 + ], + "type": "interline_equation", + "content": "\\hat {z} = \\frac {1}{\\sigma^ {2}} \\| z \\| _ {2} ^ {2} + \\underset {\\boldsymbol {z}} {\\arg \\min } \\sum_ {m = 1} ^ {M} \\mathcal {L} _ {1} \\left(f _ {\\theta} \\left(\\boldsymbol {z}, \\boldsymbol {x} _ {m}\\right), s _ {m}\\right), \\tag {1}", + "image_path": "809e762577548a668cabf91ec225a8391da6c4965c8d5e31faa1532fb73da80a.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "spans": [ + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_1" + }, + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "type": "text", + "content": " represents the clamped " + }, + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_1" + }, + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "type": "text", + "content": " distance and " + }, + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "type": "text", + "content": " is a regularization hyperparameter. Once the optimal latent code " + }, + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "type": "inline_equation", + "content": "\\hat{\\boldsymbol{z}}" + }, + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "type": "text", + "content": " is determined, the complete 3D shape can be recovered by finding the zero-SDF-value isosurface through the DeepSDF decoder " + }, + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "type": "inline_equation", + "content": "f(\\cdot)" + }, + { + "bbox": [ + 304, + 540, + 547, + 600 + ], + "type": "text", + "content": ", which is defined as:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 394, + 609, + 545, + 622 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 394, + 609, + 545, + 622 + ], + "spans": [ + { + "bbox": [ + 394, + 609, + 545, + 622 + ], + "type": "interline_equation", + "content": "\\hat {s} = f _ {\\theta} (\\hat {\\boldsymbol {z}}, \\boldsymbol {x}), \\tag {2}", + "image_path": "36cd1dd6ece46841291442f89c33d42dea993cff2fe44ce473d591e66a86eefb.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": " represents the parameters of the decoder, " + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\pmb{x} \\in \\mathbb{R}^3" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": " denotes the 3D coordinates of the querying point, and " + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\hat{s}" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": " denotes the estimated SDF value given by " + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "inline_equation", + "content": "f(\\cdot)" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": ". Here, the sign of " + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\hat{s}" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": ", either positive or negative, indicates whether the point lies on the exterior or interior of the surface, respectively. Thus, the surface of the object can be implicitly represented by the isosurface composed of points with zero SDF values." + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "8308" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 240 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 240 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 240 + ], + "type": "text", + "content": "Despite its simplicity and efficiency, DeepSDF only takes the given surface points into consideration when generating 3D shapes (i.e., Eq. (1)). This can lead to suboptimal reconstruction results in areas not captured by the partial point clouds since DeepSDF will reconstruct arbitrarily based on prior knowledge learned during training. For instance, referencing the ground truth of Case 1 in Figure 3, the reconstruction results of DeepSDF for Cases 2, 3, and 4 only demonstrate high fidelity in areas with well-captured surface points. The missing areas are reconstructed arbitrarily. To resolve this problem, we analyze multi-sweep consistency and complementarity in the latent feature space and propose implicit modeling with multi-sweep point clouds in MV-DeepSDF." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 248, + 164, + 261 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 248, + 164, + 261 + ], + "spans": [ + { + "bbox": [ + 47, + 248, + 164, + 261 + ], + "type": "text", + "content": "3.2. Approach Overview" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 266, + 287, + 302 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 266, + 287, + 302 + ], + "spans": [ + { + "bbox": [ + 46, + 266, + 287, + 302 + ], + "type": "text", + "content": "As shown in Figure 2, there are three main steps in MV-DeepSDF, namely preprocessing, optimal latent code prediction, and 3D mesh extraction." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 303, + 287, + 602 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 47, + 303, + 287, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 303, + 287, + 361 + ], + "spans": [ + { + "bbox": [ + 47, + 303, + 287, + 361 + ], + "type": "text", + "content": "1) Preprocessing. First, we carry out Farthest Point Sampling (FPS) [33] to sample a fixed number of points on each raw partial point cloud since our global feature extractor requires standardized point clouds as input. For FPS, the number of centroids is set as 256." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 363, + 287, + 517 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 363, + 287, + 517 + ], + "spans": [ + { + "bbox": [ + 46, + 363, + 287, + 517 + ], + "type": "text", + "content": "2) Optimal Latent Code Prediction. The post-FPS point clouds are used as input into the global feature extractor (yellow block in Figure 2) to extract global features for each individual point cloud. Meanwhile, the original point clouds are used to extract latent codes for each partial point cloud through the pre-trained DeepSDF (green block in Figure 2). Then, as shown in the red block of Figure 2, the global features and latent codes are concatenated as element-level representations, followed by an average pooling operation to aggregate the information into a single instance tensor. Finally, this instance tensor is transformed into the predicted latent code by a fully-connected layer as the set-level representation." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 519, + 287, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 519, + 287, + 602 + ], + "spans": [ + { + "bbox": [ + 46, + 519, + 287, + 602 + ], + "type": "text", + "content": "3) 3D Mesh Extraction. The predicted latent code is converted to an SDF using a pre-trained DeepSDF decoder [31]. The isosurface composed of querying points with zero SDF values represents the surface of the instance and the implicit surface can be rasterized to a 3D mesh using Marching Cubes [24]. Since the SDF is a continuous function, it supports 3D mesh extraction at any resolution." + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 47, + 610, + 275, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 610, + 275, + 624 + ], + "spans": [ + { + "bbox": [ + 47, + 610, + 275, + 624 + ], + "type": "text", + "content": "3.3. Consistency and Complementarity Analysis" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 629, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 287, + 714 + ], + "type": "text", + "content": "Background. In literature [37, 50], multi-view consistency refers to the consistency of describing the same instance from different viewpoint observations and multi-view complementarity refers to the complementary information of the same instance provided by different observations. Existing methods mainly explore multi-view consistency and complementarity for 3D reconstruction with par" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 310, + 71, + 538, + 150 + ], + "blocks": [ + { + "bbox": [ + 310, + 71, + 538, + 150 + ], + "lines": [ + { + "bbox": [ + 310, + 71, + 538, + 150 + ], + "spans": [ + { + "bbox": [ + 310, + 71, + 538, + 150 + ], + "type": "image", + "image_path": "d98b3d4102529c6d45a9201561ab4f13c29f0577e2ea222a69168be1c16f3a27.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 156, + 547, + 213 + ], + "lines": [ + { + "bbox": [ + 305, + 156, + 547, + 213 + ], + "spans": [ + { + "bbox": [ + 305, + 156, + 547, + 213 + ], + "type": "text", + "content": "Figure 3. The 3D reconstruction results of DeepSDF [31] (row 2) using different point clouds (row 1). All point clouds are sampled from the same CAD model of ShapeNetV2 [7]. Case 1 shows the complete dense point cloud used to train the DeepSDF decoder, while Cases 2, 3, and 4 show the partial point clouds." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 231, + 487, + 243 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 231, + 487, + 243 + ], + "spans": [ + { + "bbox": [ + 305, + 231, + 487, + 243 + ], + "type": "text", + "content": "tial point clouds in explicit modeling [34, 3]." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 243, + 545, + 351 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 243, + 545, + 351 + ], + "spans": [ + { + "bbox": [ + 304, + 243, + 545, + 351 + ], + "type": "text", + "content": "However, existing methods are not applicable for exploring multi-sweep/-view consistency and complementarity in implicit modeling because the abstract feature space operates differently than the explicit space. In implicit modeling, point clouds are expressed as low-dimensional feature vectors (a.k.a. latent vectors) in the latent feature space and the latent vectors are generated through a non-linear learning process that projects the 3D space to the feature space through a deep neural network [31, 32, 33, 49]." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 365, + 546, + 435 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 365, + 546, + 435 + ], + "spans": [ + { + "bbox": [ + 304, + 365, + 546, + 435 + ], + "type": "text", + "content": "Theoretical Analysis. Despite these differences, we can still explore multi-sweep consistency and complementarity in the latent feature space for implicit modeling. Inspired by [25], consider a total of " + }, + { + "bbox": [ + 304, + 365, + 546, + 435 + ], + "type": "inline_equation", + "content": "B" + }, + { + "bbox": [ + 304, + 365, + 546, + 435 + ], + "type": "text", + "content": " observations. The latent code for the " + }, + { + "bbox": [ + 304, + 365, + 546, + 435 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 365, + 546, + 435 + ], + "type": "text", + "content": "th observation, denoted by " + }, + { + "bbox": [ + 304, + 365, + 546, + 435 + ], + "type": "inline_equation", + "content": "z_{i}" + }, + { + "bbox": [ + 304, + 365, + 546, + 435 + ], + "type": "text", + "content": ", can be represented as:" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 379, + 437, + 545, + 449 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 379, + 437, + 545, + 449 + ], + "spans": [ + { + "bbox": [ + 379, + 437, + 545, + 449 + ], + "type": "interline_equation", + "content": "\\boldsymbol {z} _ {i} = \\boldsymbol {z} _ {i, c} + \\boldsymbol {z} _ {i, s} + \\boldsymbol {e} _ {i}, \\tag {3}", + "image_path": "8f1fe53da8b6009a15bd69976ed0730356cbe725bc2ea7376f8b94ad60bf5baa.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "spans": [ + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "inline_equation", + "content": "i = \\{1,\\dots ,B\\}" + }, + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "inline_equation", + "content": "z_{i,c}" + }, + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "text", + "content": " is the consistent component, " + }, + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "inline_equation", + "content": "z_{i,s}" + }, + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "text", + "content": " is the specific component, and " + }, + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "inline_equation", + "content": "e_i" + }, + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "text", + "content": " is the error component. In this work, " + }, + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "inline_equation", + "content": "z_{i,c}" + }, + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "inline_equation", + "content": "z_{i,s}" + }, + { + "bbox": [ + 305, + 455, + 545, + 491 + ], + "type": "text", + "content": " can be defined as follows:" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 321, + 513, + 545, + 525 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 321, + 513, + 545, + 525 + ], + "spans": [ + { + "bbox": [ + 321, + 513, + 545, + 525 + ], + "type": "interline_equation", + "content": "\\boldsymbol {z} _ {i, c} = \\boldsymbol {z} _ {i} \\cap \\boldsymbol {z} _ {g t} \\quad \\text {a n d} \\quad \\left(\\boldsymbol {z} _ {i, s} + \\boldsymbol {e} _ {i}\\right) = \\boldsymbol {z} _ {g t} - \\boldsymbol {z} _ {i}, \\tag {4}", + "image_path": "41b35b5380ac205ef7c6074844d83fec38929be4615808633c42701a90d3ddb5.jpg" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{gt}" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": " is the latent code corresponding to the ground truth shape and '∩' and '−' represent the similarity and difference in information captured by the two feature vectors, respectively. Now, consider any two consistent components " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{i,c}" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{j,c}" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": ". In the first case where " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{i,c} \\cap \\mathbf{z}_{j,c} = \\emptyset" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": ", the two components contain completely different consistent information, which is complementary. In the second case where " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{i,c} \\cap \\mathbf{z}_{j,c} \\neq \\emptyset" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": ", but " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{i,c} \\nsubseteq \\mathbf{z}_{j,c}" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{j,c} \\nsubseteq \\mathbf{z}_{i,c}" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": ", the two components contain some different information, which can be aggregated as complementary information to approach the ground truth. In the final case where " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{i,c} \\cap \\mathbf{z}_{j,c} \\neq \\emptyset" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": ", but " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{i,c} \\subseteq \\mathbf{z}_{j,c}" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{j,c} \\subseteq \\mathbf{z}_{i,c}" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": ", either " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{i,c}" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{j,c}" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": " contains redundant information from the other component. While redundant, this will not adversely impact complementary aggregation. Thus, to make the optimal " + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{z}}" + }, + { + "bbox": [ + 304, + 534, + 546, + 714 + ], + "type": "text", + "content": " approach the ground" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "8309" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "type": "text", + "content": "truth " + }, + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "type": "inline_equation", + "content": "z_{gt}" + }, + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "type": "text", + "content": ", it is desired to aggregate all consistent and complementary information among all individual features:" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 102, + 106, + 287, + 119 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 102, + 106, + 287, + 119 + ], + "spans": [ + { + "bbox": [ + 102, + 106, + 287, + 119 + ], + "type": "interline_equation", + "content": "\\hat {z} = z _ {1, c} \\cup z _ {2, c} \\dots \\cup z _ {B, c} + p, \\tag {5}", + "image_path": "6e8f8ed72d3b4383b0148d5cacfe301c124bbbf42254090710bf4dc3baa006fc.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 129, + 287, + 224 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 129, + 287, + 224 + ], + "spans": [ + { + "bbox": [ + 47, + 129, + 287, + 224 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 129, + 287, + 224 + ], + "type": "inline_equation", + "content": "\\cup" + }, + { + "bbox": [ + 47, + 129, + 287, + 224 + ], + "type": "text", + "content": " refers to the complementary aggregation of information among features and " + }, + { + "bbox": [ + 47, + 129, + 287, + 224 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 47, + 129, + 287, + 224 + ], + "type": "text", + "content": " denotes the predicted information for regions not captured in the multi-sweeps (e.g., the side of the vehicle not captured by the multi-sweeps as shown in the Cases 3 and 4 of Figure 3). In summary, with implicit modeling, we can learn the optimal latent code " + }, + { + "bbox": [ + 47, + 129, + 287, + 224 + ], + "type": "inline_equation", + "content": "\\hat{z}" + }, + { + "bbox": [ + 47, + 129, + 287, + 224 + ], + "type": "text", + "content": " by aggregating consistent (Eqs. (3)-(4)) and complementary (Eq. (5)) information among multi-sweeps." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 232, + 243, + 245 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 232, + 243, + 245 + ], + "spans": [ + { + "bbox": [ + 47, + 232, + 243, + 245 + ], + "type": "text", + "content": "3.4. Architecture Design of MV-DeepSDF" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 251, + 287, + 334 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 251, + 287, + 334 + ], + "spans": [ + { + "bbox": [ + 47, + 251, + 287, + 334 + ], + "type": "text", + "content": "To take advantage of multi-sweep consistency and complementarity in the latent feature space, we design a new architecture for implicit modeling. Our proposed architecture uses multi-sweep point clouds as model input and generates an optimal estimation of the 3D shape in the implicit space (a.k.a. the optimal latent code) as the output. The functionality of the network can be formulated as:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 118, + 344, + 287, + 357 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 118, + 344, + 287, + 357 + ], + "spans": [ + { + "bbox": [ + 118, + 344, + 287, + 357 + ], + "type": "interline_equation", + "content": "g _ {\\alpha} (\\boldsymbol {Z}, \\boldsymbol {P}) = \\hat {\\boldsymbol {z}} \\rightarrow \\boldsymbol {z} _ {g t}, \\tag {6}", + "image_path": "9f9281c5898535f47ec5ea6497ef450ce5b273bf0919c58f5882211415e5f3c6.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "spans": [ + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "inline_equation", + "content": "g(\\cdot)" + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "text", + "content": " denotes the desired network with associated parameters " + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "inline_equation", + "content": "\\alpha, Z = \\{z_1, \\dots, z_B\\}" + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "text", + "content": " denotes the set of latent codes, " + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "inline_equation", + "content": "B" + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "text", + "content": " represents the number of observations or latent codes, " + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "inline_equation", + "content": "P = \\{\\mathcal{P}_1, \\dots, \\mathcal{P}_B\\}" + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "text", + "content": " denotes the set of multi-view point clouds, and " + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "inline_equation", + "content": "\\hat{z} \\in \\mathbb{R}^{256}" + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "inline_equation", + "content": "z_{gt} \\in \\mathbb{R}^{256}" + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "text", + "content": " represent the estimated optimal and ground truth latent codes, respectively. Hence, the goal is converted into learning a network to make " + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "inline_equation", + "content": "\\hat{z}" + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "text", + "content": " approach " + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "inline_equation", + "content": "z_{gt}" + }, + { + "bbox": [ + 46, + 366, + 287, + 498 + ], + "type": "text", + "content": " for subsequent reconstructions. To this end, we devise a new architecture to realize the functionality required by simultaneously learning global features and latent codes for generating predicted latent codes." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "type": "text", + "content": "Specifically, inspired by PointNet [32], a pioneering work for 3D classification and segmentation, we transform the problem of shape estimation in the implicit space into an element-to-set feature extraction problem. Given a point cloud containing a set of 3D points, where all 3D points consistently describe a single object since they all belong to the same instance, we can learn a global feature for each point cloud that aggregates complementary features from each individual 3D point. However, only learning a global feature cannot be used for 3D reconstruction, so we propose to abstract the pipeline of PointNet (see Figure 4(a)) into a generalized process (see Figure 4(b)). As shown in Figure 4(a), PointNet first computes 3D point features using a shared MLP on each 3D point and then transforms these point features into a single global feature through max pooling. Now, suppose there exists a set composed of multiple elements. The goal of the generalized pipeline is to extract a feature for the entire set by aggregating all elements. To this" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 307, + 70, + 545, + 170 + ], + "blocks": [ + { + "bbox": [ + 307, + 70, + 545, + 170 + ], + "lines": [ + { + "bbox": [ + 307, + 70, + 545, + 170 + ], + "spans": [ + { + "bbox": [ + 307, + 70, + 545, + 170 + ], + "type": "image", + "image_path": "8655a99fe17b13bed1cc115fd249231c3ead10cf94e87828c2ebf5cfd65ea4e2.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 175, + 545, + 220 + ], + "lines": [ + { + "bbox": [ + 305, + 175, + 545, + 220 + ], + "spans": [ + { + "bbox": [ + 305, + 175, + 545, + 220 + ], + "type": "text", + "content": "Figure 4. Comparison of three pipelines. (a) The pipeline of PointNet [32]. (b) The pipeline of an abstract generalized process to extract the set feature from the elements. (c) The proposed pipeline to extract the instance feature from multi-sweep point clouds." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 242, + 545, + 301 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 242, + 545, + 301 + ], + "spans": [ + { + "bbox": [ + 304, + 242, + 545, + 301 + ], + "type": "text", + "content": "end, we propose two generalized operations. As shown in Figure 4(b), we define operation 1 as the computation of the element features (e.g., the shared MLP in PointNet) and operation 2 as the transformation of the element features into a set feature (e.g., the max pooling operation in PointNet)." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 303, + 546, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 303, + 546, + 602 + ], + "spans": [ + { + "bbox": [ + 304, + 303, + 546, + 602 + ], + "type": "text", + "content": "Using this generalized process, we can now devise our architecture to simultaneously learn global features and latent codes for generating predicted latent codes. First, we construct a global feature extractor (see yellow block in Figure 2) for learning a global feature for each point cloud that aggregates complementary features from each individual 3D point. The architecture of this feature extractor is inspired by the PCN encoder [49], a variant of PointNet [32]. This block is a stack of four PointNet [32] encoders with 128, 256, 512, and 1024 units, respectively. Since this architecture is inspired by the PCN encoder [49] and its global feature extraction operation is applied to every individual point cloud, we name it shared PCN. Meanwhile, to exploit the implicit information of each element, we employ a pre-trained DeepSDF [31] model (as denoted by Eq. (1)) to generate a latent code for each partial point cloud. Next, we concatenate the global features and latent codes to generate the element-level representations. Then, we employ average pooling and mapping to aggregate the element-level representations into a set-level predicted latent code. As shown in Figure 4(c), operation 1 of our pipeline consists of a global feature extractor and a pre-trained DeepSDF model, while operation 2 consists of concatenation, average pooling, and mapping. This pipeline realizes a symmetric operation on unordered multi-sweep point clouds." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 613, + 481, + 625 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 613, + 481, + 625 + ], + "spans": [ + { + "bbox": [ + 306, + 613, + 481, + 625 + ], + "type": "text", + "content": "3.5. Model Training of MV-DeepSDF" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 632, + 544, + 655 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 632, + 544, + 655 + ], + "spans": [ + { + "bbox": [ + 306, + 632, + 544, + 655 + ], + "type": "text", + "content": "We adopt a curriculum learning strategy for model training, which consists of two stages." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "content": "Stage One. In stage one, we pre-train the DeepSDF decoder using watertight CAD models belonging to the car taxonomy of the ShapeNetV2 dataset [7]. The latent code " + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "inline_equation", + "content": "z" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8310" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 277, + 85 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 277, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 277, + 85 + ], + "type": "text", + "content": "and parameters of the decoder " + }, + { + "bbox": [ + 47, + 72, + 277, + 85 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 47, + 72, + 277, + 85 + ], + "type": "text", + "content": " are jointly optimized as:" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 53, + 92, + 287, + 136 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 92, + 287, + 136 + ], + "spans": [ + { + "bbox": [ + 53, + 92, + 287, + 136 + ], + "type": "interline_equation", + "content": "\\underset {\\theta , \\left\\{\\boldsymbol {z} _ {j} \\right\\} _ {j = 1} ^ {J}} {\\arg \\min } \\sum_ {j = 1} ^ {J} \\left(\\frac {1}{\\sigma^ {2}} \\left\\| \\boldsymbol {z} _ {j} \\right\\| _ {2} ^ {2} + \\sum_ {k = 1} ^ {K} \\mathcal {L} _ {1} \\left(f _ {\\theta} \\left(\\boldsymbol {z} _ {j}, \\boldsymbol {x} _ {k}\\right), s _ {k}\\right)\\right), \\tag {7}", + "image_path": "ae9e376675334eb691f93f0c49a53854ac542ee56144b49732c3409783e42d01.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 137, + 287, + 209 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 137, + 287, + 209 + ], + "spans": [ + { + "bbox": [ + 46, + 137, + 287, + 209 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 137, + 287, + 209 + ], + "type": "inline_equation", + "content": "J" + }, + { + "bbox": [ + 46, + 137, + 287, + 209 + ], + "type": "text", + "content": " represents the number of 3D shapes used for training and " + }, + { + "bbox": [ + 46, + 137, + 287, + 209 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 46, + 137, + 287, + 209 + ], + "type": "text", + "content": " represents the number of points for each shape. During this stage, the decoder gains prior knowledge of vehicle shapes and once trained, the decoder remains fixed for the latent code generation step of our pipeline. Please refer to [31] for the details of the training at this step." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 223, + 289, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 223, + 289, + 594 + ], + "spans": [ + { + "bbox": [ + 46, + 223, + 289, + 594 + ], + "type": "text", + "content": "Training Dataset Preparation for Stage Two. As shown in Eq. (6), ground truth latent codes, partial point clouds, and their corresponding latent codes are required for training the reconstruction network. However, real-world datasets, such as Waymo [36] and KITTI [15], do not contain ground truth shapes, so it is necessary to use a synthetic dataset [7] for generating the training data. To resolve this problem, we utilize the latent codes of the training shapes (e.g., the complete dense point cloud shown in Case 1 of Figure 3) as ground truth latent codes in the second stage of model training. As for the partial point clouds, the domain gap between training instances and in-the-wild instances directly determines the ability of our network to generalize to real-world datasets. To reduce the domain gap, we adopt PCGen [23] as our partial point cloud generation method. PCGen places a virtual LiDAR with real-world parameters (resolution and sampling pattern) around the vehicle and simulates the point cloud captured by the virtual LiDAR. This differs from the method used by DeepSDF [31], where a simulated depth camera is used as the virtual sensor instead of a LiDAR. A visual comparison of the real-world point cloud and simulated partial point clouds obtained using various methods is given in Figure 5. As shown in Figure 5, the partial point clouds of PCGen [23] are visually closer to the in-the-wild LiDAR sweeps of Waymo [36] and KITTI [15] than those of the virtual depth camera approach [31], which only raycasts evenly in the inclination and azimuth directions. Apart from this visual superiority, the advantages of generating partial point clouds with PCGen can also be observed through the improved generalization ability of our network. See experiments for further details." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": "When generating training data from ShapeNetV2 [7], we randomly sample one side of the vehicle to accurately reflect the real-world scan of a LiDAR on an ego-vehicle. In this way, we produce six partial point clouds for each vehicle. The virtual LiDAR pose for each partial point cloud is generated using a set of restrictions. These restrictions are set by considering the possible relative poses of an ego vehicle's LiDAR in the coordinate system of the other vehicle. In particular, " + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\theta \\in [0^{\\circ}, 180^{\\circ}]" + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\theta \\in [-180^{\\circ}, 0^{\\circ}]" + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "r \\in [3, 15]" + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "h \\in [0.8, 1.2]" + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": " are used, where " + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": " represents the azimuth," + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 318, + 70, + 425, + 136 + ], + "blocks": [ + { + "bbox": [ + 318, + 70, + 425, + 136 + ], + "lines": [ + { + "bbox": [ + 318, + 70, + 425, + 136 + ], + "spans": [ + { + "bbox": [ + 318, + 70, + 425, + 136 + ], + "type": "image", + "image_path": "30f16c703f4b656e8cd24191236d3e2ffc85da5d9a635d276f612e95c5a0088c.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 429, + 71, + 536, + 136 + ], + "blocks": [ + { + "bbox": [ + 429, + 71, + 536, + 136 + ], + "lines": [ + { + "bbox": [ + 429, + 71, + 536, + 136 + ], + "spans": [ + { + "bbox": [ + 429, + 71, + 536, + 136 + ], + "type": "image", + "image_path": "f4c86d858ccb74fdc389d952f3babf758bf13160c0d7362dad6fc71a34885111.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 380, + 137, + 476, + 168 + ], + "blocks": [ + { + "bbox": [ + 367, + 137, + 380, + 144 + ], + "lines": [ + { + "bbox": [ + 367, + 137, + 380, + 144 + ], + "spans": [ + { + "bbox": [ + 367, + 137, + 380, + 144 + ], + "type": "text", + "content": "(c)" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 476, + 137, + 488, + 144 + ], + "lines": [ + { + "bbox": [ + 476, + 137, + 488, + 144 + ], + "spans": [ + { + "bbox": [ + 476, + 137, + 488, + 144 + ], + "type": "text", + "content": "(d)" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 380, + 137, + 476, + 168 + ], + "lines": [ + { + "bbox": [ + 380, + 137, + 476, + 168 + ], + "spans": [ + { + "bbox": [ + 380, + 137, + 476, + 168 + ], + "type": "image", + "image_path": "2751cdca10a3d5ed7d1d8229aaab772a1213df621f962171f15d1a2be7fe2f44.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 422, + 167, + 433, + 176 + ], + "lines": [ + { + "bbox": [ + 422, + 167, + 433, + 176 + ], + "spans": [ + { + "bbox": [ + 422, + 167, + 433, + 176 + ], + "type": "text", + "content": "(e)" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 304, + 182, + 547, + 272 + ], + "lines": [ + { + "bbox": [ + 304, + 182, + 547, + 272 + ], + "spans": [ + { + "bbox": [ + 304, + 182, + 547, + 272 + ], + "type": "text", + "content": "Figure 5. Visual comparison of in-the-wild partial point clouds and raycasted point clouds. (a) A partial point cloud from the Waymo tracking dataset [36]. (b) The raycasted point cloud generated by PCGen [23] using the LiDAR parameters of Waymo. (c) A partial point cloud from the KITTI tracking dataset [15]. (d) The raycasted point cloud generated by PCGen [23] using the LiDAR parameters of KITTI. (e) The raycasted point cloud obtained from the virtual depth camera approach used by DeepSDF [31]." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "spans": [ + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "text", + "content": " represents the distance between the LiDAR and the vehicle, and " + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "inline_equation", + "content": "h" + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "text", + "content": " represents the height of the LiDAR to the ground. " + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "inline_equation", + "content": "\\theta, r," + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "inline_equation", + "content": "h" + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "text", + "content": " describes the pose of the virtual LiDAR with respect to the frame of the other vehicle. Both " + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "inline_equation", + "content": "h" + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "text", + "content": " are expressed in the normalized space, where the size of the vehicle is normalized into the range " + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "inline_equation", + "content": "[-1, 1]" + }, + { + "bbox": [ + 304, + 291, + 545, + 376 + ], + "type": "text", + "content": ". Finally, we generate a latent code for each partial point cloud using Eq. (1)." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "spans": [ + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "text", + "content": "Stage Two. In stage two, the network is trained to reconstruct 3D vehicles from multi-view partial point clouds and their corresponding latent codes. Consider the " + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "inline_equation", + "content": "c" + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "text", + "content": "th vehicle instance. Let " + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "inline_equation", + "content": "P_{B,c}" + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "text", + "content": " represent the set of partial point clouds, " + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "inline_equation", + "content": "Z_{B,c}" + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "text", + "content": " represent the set of latent codes corresponding to the multi-view point clouds, and " + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "inline_equation", + "content": "z_{gt,c}" + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "text", + "content": " represent the ground truth latent code acquired from stage one. Furthermore, let " + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "inline_equation", + "content": "g(\\cdot)" + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "text", + "content": " represent the function of the implicit shape prediction network (refer to yellow and red blocks in Figure 2) and " + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 391, + 546, + 523 + ], + "type": "text", + "content": " represent the parameters of the model. The training objective of stage two can be defined as:" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 341, + 533, + 545, + 564 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 341, + 533, + 545, + 564 + ], + "spans": [ + { + "bbox": [ + 341, + 533, + 545, + 564 + ], + "type": "interline_equation", + "content": "\\underset {\\alpha} {\\arg \\min } \\sum_ {c = 1} ^ {C} \\mathcal {L} _ {2} \\left(g _ {\\alpha} \\left(\\boldsymbol {Z} _ {B, c}, \\boldsymbol {P} _ {B, c}\\right), \\boldsymbol {z} _ {g t, c}\\right), \\tag {8}", + "image_path": "aa2e4fedc096b3e6bd255eb9cbca60d9d850cf0ac24fd9ac07d2cfe929444f9c.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 573, + 547, + 611 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 573, + 547, + 611 + ], + "spans": [ + { + "bbox": [ + 304, + 573, + 547, + 611 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 573, + 547, + 611 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 304, + 573, + 547, + 611 + ], + "type": "text", + "content": " represents the number of instances employed for training and " + }, + { + "bbox": [ + 304, + 573, + 547, + 611 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_2" + }, + { + "bbox": [ + 304, + 573, + 547, + 611 + ], + "type": "text", + "content": " is the Mean Squared Error loss. The training details are presented in Sec. 4.1." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 621, + 388, + 635 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 621, + 388, + 635 + ], + "spans": [ + { + "bbox": [ + 306, + 621, + 388, + 635 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 642, + 547, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 547, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 547, + 712 + ], + "type": "text", + "content": "In this section, we present qualitative and quantitative results on two real-world autonomous driving datasets, namely Waymo [36] and KITTI [15]. The multi-sweep point clouds for Waymo are collected from 136 unique vehicle instances of Waymo Open Dataset's tracking data [36], while those for KITTI are extracted from 233 vehicle in" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 758 + ], + "type": "text", + "content": "8311" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 71, + 545, + 208 + ], + "blocks": [ + { + "bbox": [ + 49, + 71, + 545, + 208 + ], + "lines": [ + { + "bbox": [ + 49, + 71, + 545, + 208 + ], + "spans": [ + { + "bbox": [ + 49, + 71, + 545, + 208 + ], + "type": "image", + "image_path": "468cb5d1e2e84e3ea597ed086246a8b1ec77fd0131991a6d33b9438fea42ba94.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 213, + 546, + 236 + ], + "lines": [ + { + "bbox": [ + 46, + 213, + 546, + 236 + ], + "spans": [ + { + "bbox": [ + 46, + 213, + 546, + 236 + ], + "type": "text", + "content": "Figure 6. Visual comparison with the state-of-the-art methods (DeepSDF [31], C-DeepSDF [11], MendNet [12], and AdaPoinTr [48]) on the Waymo [36] dataset. DeepSDF+MS and MendNet+MS indicate the models with multi-sweep input." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 255, + 287, + 304 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 255, + 287, + 304 + ], + "spans": [ + { + "bbox": [ + 46, + 255, + 287, + 304 + ], + "type": "text", + "content": "stances of KITTI's tracking dataset [15]. Due to page limitations, experiment details and some results (e.g., the results on the synthetic dataset ShapeNetV2 [7]) are discussed in the supplementary material." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 309, + 180, + 322 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 309, + 180, + 322 + ], + "spans": [ + { + "bbox": [ + 47, + 309, + 180, + 322 + ], + "type": "text", + "content": "4.1. Implementation Details" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 328, + 288, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 328, + 288, + 460 + ], + "spans": [ + { + "bbox": [ + 46, + 328, + 288, + 460 + ], + "type": "text", + "content": "Architecture Details. Our global feature extractor, named shared PCN, is a variant of the PCN encoder [49]. The embedded shared MLP layers are identical to those of PointNet [32], which are implemented using 1D convolution layers. Moreover, since DeepSDF [31] normalizes the latent codes into the range " + }, + { + "bbox": [ + 46, + 328, + 288, + 460 + ], + "type": "inline_equation", + "content": "[-1, 1]" + }, + { + "bbox": [ + 46, + 328, + 288, + 460 + ], + "type": "text", + "content": ", we add a tanh layer after the last shared MLP to normalize the global features into the same range as the latent codes. The decoder is identical to that of DeepSDF [31]. We report results based on an implementation with Python and PyTorch, but our approach also supports implementation with MindSpore [20]." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 473, + 287, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 473, + 287, + 665 + ], + "spans": [ + { + "bbox": [ + 46, + 473, + 287, + 665 + ], + "type": "text", + "content": "Training Details. In the first stage of training, we follow the same method as presented in DeepSDF [31] to train the decoder using watertight CAD models from the car taxonomy of ShapeNetV2 [7]. Once trained, the decoder is fixed and projects a 256-dimensional latent code to an SDF in 3D space. In the second stage, we train the model for 20 epochs using the Adam optimizer [21] with a learning rate of 1e-5. The batch size is set to 1, allowing the model to simultaneously see all 6 frames of the given instance at each iteration. Since both the output of the model and the supervision are 1D vectors, the loss computation is very fast. It only takes 10 minutes to train our network on a single NVIDIA GeForce RTX 2080 GPU during stage two. However, the DeepSDF decoder [31] used to prepare the training dataset for stage two through latent code generation is a more time-consuming process." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 671, + 163, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 671, + 163, + 682 + ], + "spans": [ + { + "bbox": [ + 47, + 671, + 163, + 682 + ], + "type": "text", + "content": "4.2. Evaluation Protocol" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 689, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 689, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 689, + 287, + 713 + ], + "type": "text", + "content": "Metrics. Since an in-the-wild instance does not have a ground truth 3D shape, we follow [12] to evaluate the recon" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 255, + 545, + 350 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 255, + 545, + 350 + ], + "spans": [ + { + "bbox": [ + 304, + 255, + 545, + 350 + ], + "type": "text", + "content": "struction results. In particular, the multiple LiDAR sweeps are stacked to construct the ground truth points set " + }, + { + "bbox": [ + 304, + 255, + 545, + 350 + ], + "type": "inline_equation", + "content": "\\pmb{X}" + }, + { + "bbox": [ + 304, + 255, + 545, + 350 + ], + "type": "text", + "content": ". Moreover, we sample 30,000 points on the surface of each reconstructed mesh to generate the reconstruction points set " + }, + { + "bbox": [ + 304, + 255, + 545, + 350 + ], + "type": "inline_equation", + "content": "\\pmb{Y}" + }, + { + "bbox": [ + 304, + 255, + 545, + 350 + ], + "type": "text", + "content": ". We employ Asymmetric Chamfer Distance (ACD) [12], which is the sum of the squared distance of each ground truth point to the nearest point in the reconstructed point set, to evaluate reconstruction results on real-world datasets:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 350, + 355, + 545, + 380 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 350, + 355, + 545, + 380 + ], + "spans": [ + { + "bbox": [ + 350, + 355, + 545, + 380 + ], + "type": "interline_equation", + "content": "\\operatorname {A C D} \\left(\\boldsymbol {X}, \\boldsymbol {Y}\\right) = \\sum_ {\\boldsymbol {x} \\in \\boldsymbol {X}} \\min _ {\\boldsymbol {y} \\in \\boldsymbol {Y}} \\| x - \\boldsymbol {y} \\| _ {2} ^ {2}. \\tag {9}", + "image_path": "6c59749aca0554227b4588d66884532b18ce19003f07b4a0a17c0a71f239f57a.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 385, + 545, + 421 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 385, + 545, + 421 + ], + "spans": [ + { + "bbox": [ + 304, + 385, + 545, + 421 + ], + "type": "text", + "content": "For ACD, a smaller value is preferred. In addition, we compute the recall of the ground truth points from the reconstructed shape, which is defined as:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 312, + 426, + 545, + 455 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 426, + 545, + 455 + ], + "spans": [ + { + "bbox": [ + 312, + 426, + 545, + 455 + ], + "type": "interline_equation", + "content": "\\operatorname {R e c a l l} (\\boldsymbol {X}, \\boldsymbol {Y}) = \\frac {1}{| \\boldsymbol {X} |} \\sum_ {x \\in \\boldsymbol {X}} \\left[ \\min _ {y \\in \\boldsymbol {Y}} \\| x - y \\| _ {2} ^ {2} < = t \\right], \\tag {10}", + "image_path": "7aa0cbd6d7bace6c7e1006269108bbe19b2485ce1b679442ef5d63eb93f838a4.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 460, + 506, + 472 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 460, + 506, + 472 + ], + "spans": [ + { + "bbox": [ + 306, + 460, + 506, + 472 + ], + "type": "text", + "content": "where the threshold " + }, + { + "bbox": [ + 306, + 460, + 506, + 472 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 306, + 460, + 506, + 472 + ], + "type": "text", + "content": " is set as 0.1, following [12]." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 486, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 486, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 486, + 546, + 713 + ], + "type": "text", + "content": "Competitors. We compare our approach with four state-of-the-art methods, including three implicit modeling-based methods (DeepSDF [31], C-DeepSDF [11], and MendNet [12]) and AdaPoinTr [48], which is built upon PoinTr++ [47], the winner of Multi-View Partial Point Cloud Challenge 2021 on Completion and Registration [30]. Training data for DeepSDF and C-DeepSDF are generated following the original papers, while MendNet uses PCGen [23] to generate training data. The pipeline of AdaPoinTr [48] requires online generation of partial point clouds using the virtual depth camera approach and since it is not trivial to replace this process with PCGen, AdaPoinTr is trained using the default setup without PCGen. Note that with multi-sweep point clouds, competitors generate multiple reconstruction results (one for each partial point cloud), so we compare with the best single-shot reconstruction result, which is the mesh with the minimum ACD among the multiple single-shot reconstructed meshes. Furthermore, we report the results of DeepSDF and MendNet with multi-sweep" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "8312" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 51, + 70, + 283, + 172 + ], + "blocks": [ + { + "bbox": [ + 51, + 70, + 283, + 172 + ], + "lines": [ + { + "bbox": [ + 51, + 70, + 283, + 172 + ], + "spans": [ + { + "bbox": [ + 51, + 70, + 283, + 172 + ], + "type": "table", + "html": "
Method \\ MetricACDmean ↓ACDmedian ↓Recall ↑
DeepSDF [31]6.265.8193.51
DeepSDF+MS5.125.0995.57
C-DeepSDF [11]6.215.6493.98
MendNet [12]4.924.7995.39
MendNet+MS4.854.7795.76
AdaPoinTr*[48]4.794.7495.95
Ours-VDC4.764.5596.05
Ours3.362.2696.84
", + "image_path": "cf73b2e96ff7708ab265aa1ac7cb23fba8a3f707607d85073d9d2251289df6d2.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 47, + 172, + 286, + 248 + ], + "lines": [ + { + "bbox": [ + 47, + 172, + 286, + 248 + ], + "spans": [ + { + "bbox": [ + 47, + 172, + 286, + 248 + ], + "type": "text", + "content": "Table 1. Comparison with the state-of-the-art methods on Waymo. ACD " + }, + { + "bbox": [ + 47, + 172, + 286, + 248 + ], + "type": "inline_equation", + "content": "\\downarrow" + }, + { + "bbox": [ + 47, + 172, + 286, + 248 + ], + "type": "text", + "content": " is multiplied by " + }, + { + "bbox": [ + 47, + 172, + 286, + 248 + ], + "type": "inline_equation", + "content": "10^{3}" + }, + { + "bbox": [ + 47, + 172, + 286, + 248 + ], + "type": "text", + "content": ". Recall " + }, + { + "bbox": [ + 47, + 172, + 286, + 248 + ], + "type": "inline_equation", + "content": "\\uparrow" + }, + { + "bbox": [ + 47, + 172, + 286, + 248 + ], + "type": "text", + "content": " is presented as a percentage. *AdaPoinTr is trained with the default setup without PCGen on the large-scale ShapeNet-55 [47] following the original paper [48], and then fine-tuned on the car taxonomy of ShapeNetV2 in our experiments. Other methods are only trained with the car taxonomy of ShapeNetV2." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 269, + 286, + 364 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 269, + 286, + 364 + ], + "spans": [ + { + "bbox": [ + 47, + 269, + 286, + 364 + ], + "type": "text", + "content": "inputs (denoted as DeepSDF+MS and MendNet+MS), in which we stack the partial point clouds of multi-sweeps into a single point cloud and perform single-shot-based reconstruction on this stacked point cloud. For our approach, in addition to the default setup which generates the training dataset using PCGen (denoted as Ours), we also adapt our approach to use training data generated by the virtual depth camera approach [31] (denoted as Ours-VDC)." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 372, + 156, + 384 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 372, + 156, + 384 + ], + "spans": [ + { + "bbox": [ + 47, + 372, + 156, + 384 + ], + "type": "text", + "content": "4.3. Results on Waymo" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 390, + 286, + 557 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 390, + 286, + 557 + ], + "spans": [ + { + "bbox": [ + 47, + 390, + 286, + 557 + ], + "type": "text", + "content": "The qualitative and quantitative comparisons of our approach with the state-of-the-art methods are presented in Figure 6 and Table 1, respectively. Overall, our approach achieves the best reconstruction results both qualitatively and quantitatively. Specifically, from Figure 6 and Table 1, we can see that DeepSDF [31] and C-DeepSDF [11] are sensitive to noise, resulting in low fidelity. MendNet [12] generates more stable results than DeepSDF and C-DeepSDF, but its reconstruction meshes contain some irregular holes on the surface (see sixth column of Figure 6). Although AdaPoinTr [48] outputs point clouds with good fidelity, it expresses the shape with a limited resolution and thus fails to describe continuous local details (see seventh column of Figure 6)." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 558, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 558, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 47, + 558, + 286, + 712 + ], + "type": "text", + "content": "Compared with vanilla DeepSDF and MendNet, DeepSDF+MS and MendNet+MS yield messier surfaces/structures (see fourth and eighth columns of Figure 6), despite their better metric scores. This shows that even though transforming all partial point clouds into a single frame does benefit information aggregation, it also accumulates noise and annotation errors in the process. Hence, due to noise in real-world data, it is not practical to geometrically stack multi-sweep point clouds and directly perform single-shot-based reconstruction. In comparison, our approach generates smooth watertight shapes (see last two columns of Figure 6) with high fidelity (see Table 1). Furthermore, Ours outperforms Ours-VDC, which indicates" + } + ] + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 310, + 71, + 542, + 172 + ], + "blocks": [ + { + "bbox": [ + 310, + 71, + 542, + 172 + ], + "lines": [ + { + "bbox": [ + 310, + 71, + 542, + 172 + ], + "spans": [ + { + "bbox": [ + 310, + 71, + 542, + 172 + ], + "type": "table", + "html": "
Method \\ MetricACDmean ↓ACDmedian ↓Recall ↑
DeepSDF [31]6.816.1780.65
DeepSDF+MS6.115.8382.73
C-DeepSDF [11]6.735.9980.77
MendNet [12]5.945.6483.84
MendNet+MS5.835.6184.26
AdaPoinTr [48]5.895.6784.20
Ours-VDC5.755.2484.39
Ours4.273.0185.88
", + "image_path": "83965e8d867b2d2664ba18ba8b2f3149a6b4eed1b7b0e37cf00a56a3ff686555.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 306, + 172, + 544, + 194 + ], + "lines": [ + { + "bbox": [ + 306, + 172, + 544, + 194 + ], + "spans": [ + { + "bbox": [ + 306, + 172, + 544, + 194 + ], + "type": "text", + "content": "Table 2. Comparison with the state-of-the-art methods on KITTI. ACD " + }, + { + "bbox": [ + 306, + 172, + 544, + 194 + ], + "type": "inline_equation", + "content": "\\downarrow" + }, + { + "bbox": [ + 306, + 172, + 544, + 194 + ], + "type": "text", + "content": " is multiplied by " + }, + { + "bbox": [ + 306, + 172, + 544, + 194 + ], + "type": "inline_equation", + "content": "{10}^{3}" + }, + { + "bbox": [ + 306, + 172, + 544, + 194 + ], + "type": "text", + "content": " . Recall " + }, + { + "bbox": [ + 306, + 172, + 544, + 194 + ], + "type": "inline_equation", + "content": "\\uparrow" + }, + { + "bbox": [ + 306, + 172, + 544, + 194 + ], + "type": "text", + "content": " is presented as a percentage." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 215, + 545, + 250 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 215, + 545, + 250 + ], + "spans": [ + { + "bbox": [ + 305, + 215, + 545, + 250 + ], + "type": "text", + "content": "that using PCGen to prepare training partial point clouds (refer to Figure 5) reduces the domain gap between training and in-the-wild instances." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 259, + 411, + 272 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 259, + 411, + 272 + ], + "spans": [ + { + "bbox": [ + 306, + 259, + 411, + 272 + ], + "type": "text", + "content": "4.4. Results on KITTI" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 278, + 545, + 422 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 278, + 545, + 422 + ], + "spans": [ + { + "bbox": [ + 304, + 278, + 545, + 422 + ], + "type": "text", + "content": "The qualitative and quantitative comparisons of our approach against the state-of-the-art methods are presented in Figure 7 and Table 2, respectively. From these results, we can also observe the superior performance of our approach over the state-of-the-art competitors. Specifically, qualitatively, as shown in Figure 7, our approaches (Ours and Ours-VDC) are more robust to noise when compared to DeepSDF [31], DeepSDF+MS, and C-DeepSDF [11] and generate smoother, watertight surfaces compared to MendNet [12], AdaPoinTr [48], and MendNet+MS. Quantitatively, as shown in Table 2, Ours yields the best ACD and Recall results, while Ours-VDC performs the second best." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 431, + 400, + 443 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 431, + 400, + 443 + ], + "spans": [ + { + "bbox": [ + 306, + 431, + 400, + 443 + ], + "type": "text", + "content": "4.5. Ablation Study" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 450, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 450, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 450, + 545, + 713 + ], + "type": "text", + "content": "To verify the effectiveness of the main components of our approach, we carry out a series of experiments on Waymo [36] as shown in Table 3. The first row of Table 3 refers to the baseline model of our approach, which is a shared PCN encoder (Enc.) (yellow block in Figure 2) followed by an average pooling layer (Avg.). This architecture is similar to that of MendNet [12], which adds two stacked PointNet encoders [32] to the DeepSDF decoder. In the second row, we directly use bitwise multiplication to merge the global features " + }, + { + "bbox": [ + 304, + 450, + 545, + 713 + ], + "type": "inline_equation", + "content": "(\\mathrm{B} \\times 256" + }, + { + "bbox": [ + 304, + 450, + 545, + 713 + ], + "type": "text", + "content": ", instead of " + }, + { + "bbox": [ + 304, + 450, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathrm{B} \\times 1024)" + }, + { + "bbox": [ + 304, + 450, + 545, + 713 + ], + "type": "text", + "content": " and the latent codes " + }, + { + "bbox": [ + 304, + 450, + 545, + 713 + ], + "type": "inline_equation", + "content": "(\\mathrm{B} \\times 256)" + }, + { + "bbox": [ + 304, + 450, + 545, + 713 + ], + "type": "text", + "content": ". However, this results in obvious performance degradation, which shows that directly merging the global features and latent codes obtained from multi-sweep information does not bring improvement to our baseline model. In comparison, in the third row, we add our proposed components, namely the input of latent codes (Dep.), concatenation (Con.), and mapping (Map.), to the baseline model, but with max pooling. This brings significant performance improvement compared to the first and second rows. Then, in the last row, we further replace max pooling with average pooling, which includes all proposed components of this work. This yields the best results." + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8313" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 71, + 545, + 208 + ], + "blocks": [ + { + "bbox": [ + 51, + 71, + 545, + 208 + ], + "lines": [ + { + "bbox": [ + 51, + 71, + 545, + 208 + ], + "spans": [ + { + "bbox": [ + 51, + 71, + 545, + 208 + ], + "type": "image", + "image_path": "18f87ca6b80bdaed4bb7c8ec381d474b6a20ba3ca66c6d70847942fa6993c4db.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 211, + 546, + 235 + ], + "lines": [ + { + "bbox": [ + 46, + 211, + 546, + 235 + ], + "spans": [ + { + "bbox": [ + 46, + 211, + 546, + 235 + ], + "type": "text", + "content": "Figure 7. Visual comparison with the state-of-the-art methods (DeepSDF [31], C-DeepSDF [11], MendNet [12], and AdaPoinTr [48]) on the KITTI [15] dataset. DeepSDF+MS and MendNet+MS indicate the models with multi-sweep input." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 52, + 252, + 282, + 323 + ], + "blocks": [ + { + "bbox": [ + 52, + 252, + 282, + 323 + ], + "lines": [ + { + "bbox": [ + 52, + 252, + 282, + 323 + ], + "spans": [ + { + "bbox": [ + 52, + 252, + 282, + 323 + ], + "type": "table", + "html": "
Operation 1Operation 2Metric
Enc.Dep.Mer.PoolMap.ACD ↓Recall ↑
✓Avg.4.8995.50
✓✓Mul.Avg.7.3384.93
✓✓Con.Max.✓4.3596.61
✓✓Con.Avg.✓3.3696.84
", + "image_path": "dc1b8de9766d03ee2e3024b190de68a4a14c41b1cd1c8d0ef546e96cc9391c10.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 46, + 323, + 286, + 411 + ], + "lines": [ + { + "bbox": [ + 46, + 323, + 286, + 411 + ], + "spans": [ + { + "bbox": [ + 46, + 323, + 286, + 411 + ], + "type": "text", + "content": "Table 3. The ablation study of the proposed framework. Refer to Figure 4(b) to see the definitions of operations 1 and 2. Enc.: the shared PCN encoder; Dep.: latent code generation through DeepSDF as input; Mer.: the operation to merge global features and latent codes; Map.: the mapping conducted by the fully-connected layer; Con.: the concatenation; Mul.: the bitwise multiplication; Avg.: average pooling; Max.: max pooling. ACD " + }, + { + "bbox": [ + 46, + 323, + 286, + 411 + ], + "type": "inline_equation", + "content": "\\downarrow" + }, + { + "bbox": [ + 46, + 323, + 286, + 411 + ], + "type": "text", + "content": " is multiplied by " + }, + { + "bbox": [ + 46, + 323, + 286, + 411 + ], + "type": "inline_equation", + "content": "10^{3}" + }, + { + "bbox": [ + 46, + 323, + 286, + 411 + ], + "type": "text", + "content": ". Recall " + }, + { + "bbox": [ + 46, + 323, + 286, + 411 + ], + "type": "inline_equation", + "content": "\\uparrow" + }, + { + "bbox": [ + 46, + 323, + 286, + 411 + ], + "type": "text", + "content": " is presented as a percentage." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 431, + 217, + 442 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 431, + 217, + 442 + ], + "spans": [ + { + "bbox": [ + 47, + 431, + 217, + 442 + ], + "type": "text", + "content": "4.6. Extension to Other Taxonomies" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 449, + 287, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 449, + 287, + 640 + ], + "spans": [ + { + "bbox": [ + 46, + 449, + 287, + 640 + ], + "type": "text", + "content": "It is straightforward to extend the proposed shape completion framework to other taxonomies. Suppose that we want to extend MV-DeepSDF to perform shape completion on sofas. First, a new DeepSDF decoder [31] needs to be pre-trained using watertight CAD models from the sofa taxonomy of ShapeNetV2 [7] or another synthetic dataset. Then, PCGen [23] or another sampling technique (e.g., the approaches proposed in [31, 47]) can be used to generate partial point clouds for each sofa instance. These partial point clouds are then passed into the pre-trained DeepSDF decoder [31] to produce their corresponding latent codes. Finally, the partial point clouds and latent codes can be used together to train MV-DeepSDF. Following the pipeline above, we evaluate on indoor sofas of ShapeNetV2 and outdoor cyclists of Waymo and show that our method is versatile and extendible to other taxonomies (see Figure 8)." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 642, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 288, + 714 + ], + "type": "text", + "content": "While existing datasets, such as ScanNet [8] and Semantic3D [18], provide real-world point cloud data for many taxonomies, the availability of tracking data for multisweep scans is still fairly limited to the autonomous driving industry. Hence, it is necessary to first obtain the corresponding multi-sweep tracking labels for the desired class" + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 322, + 266, + 372, + 291 + ], + "blocks": [ + { + "bbox": [ + 322, + 266, + 372, + 291 + ], + "lines": [ + { + "bbox": [ + 322, + 266, + 372, + 291 + ], + "spans": [ + { + "bbox": [ + 322, + 266, + 372, + 291 + ], + "type": "image", + "image_path": "c4cb8880ef53068dcf8ed84513b605e3aac76208b6df9007a5488ed48d7d2f16.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 331, + 298, + 366, + 308 + ], + "lines": [ + { + "bbox": [ + 331, + 298, + 366, + 308 + ], + "spans": [ + { + "bbox": [ + 331, + 298, + 366, + 308 + ], + "type": "text", + "content": "DeepSDF" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 381, + 268, + 431, + 293 + ], + "blocks": [ + { + "bbox": [ + 381, + 268, + 431, + 293 + ], + "lines": [ + { + "bbox": [ + 381, + 268, + 431, + 293 + ], + "spans": [ + { + "bbox": [ + 381, + 268, + 431, + 293 + ], + "type": "image", + "image_path": "a875898f1b839db6763c802e3a3a8a78f181d0a0411b55198939f8d323fdada3.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 400, + 299, + 417, + 308 + ], + "lines": [ + { + "bbox": [ + 400, + 299, + 417, + 308 + ], + "spans": [ + { + "bbox": [ + 400, + 299, + 417, + 308 + ], + "type": "text", + "content": "Ours" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 443, + 255, + 480, + 297 + ], + "blocks": [ + { + "bbox": [ + 443, + 255, + 480, + 297 + ], + "lines": [ + { + "bbox": [ + 443, + 255, + 480, + 297 + ], + "spans": [ + { + "bbox": [ + 443, + 255, + 480, + 297 + ], + "type": "image", + "image_path": "7e5ebe97fcaccc30098413a0ea2f79925b9794c31ed7eb0f6025987cd27b1331.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 444, + 299, + 478, + 308 + ], + "lines": [ + { + "bbox": [ + 444, + 299, + 478, + 308 + ], + "spans": [ + { + "bbox": [ + 444, + 299, + 478, + 308 + ], + "type": "text", + "content": "DeepSDF" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 306, + 315, + 545, + 337 + ], + "lines": [ + { + "bbox": [ + 306, + 315, + 545, + 337 + ], + "spans": [ + { + "bbox": [ + 306, + 315, + 545, + 337 + ], + "type": "text", + "content": "Figure 8. Visual comparison of DeepSDF and MV-DeepSDF on the indoor sofa of ShapeNetV2 and the outdoor cyclist of Waymo." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 496, + 255, + 525, + 297 + ], + "blocks": [ + { + "bbox": [ + 496, + 255, + 525, + 297 + ], + "lines": [ + { + "bbox": [ + 496, + 255, + 525, + 297 + ], + "spans": [ + { + "bbox": [ + 496, + 255, + 525, + 297 + ], + "type": "image", + "image_path": "08de1cbce990fce5abfa5b29c3e4924de05892e5dee43379958883d6205407c4.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 505, + 299, + 522, + 307 + ], + "lines": [ + { + "bbox": [ + 505, + 299, + 522, + 307 + ], + "spans": [ + { + "bbox": [ + 505, + 299, + 522, + 307 + ], + "type": "text", + "content": "Ours" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 354, + 544, + 367 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 354, + 544, + 367 + ], + "spans": [ + { + "bbox": [ + 306, + 354, + 544, + 367 + ], + "type": "text", + "content": "when choosing to adopt MV-DeepSDF on a new taxonomy." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 376, + 378, + 388 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 376, + 378, + 388 + ], + "spans": [ + { + "bbox": [ + 306, + 376, + 378, + 388 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 396, + 545, + 586 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 396, + 545, + 586 + ], + "spans": [ + { + "bbox": [ + 304, + 396, + 545, + 586 + ], + "type": "text", + "content": "In this work, we propose a new MV-DeepSDF framework to facilitate implicit modeling with multi-sweep point clouds for autonomous driving. The main idea is to abstract 3D vehicle reconstruction from multi-sweeps into an element-to-set feature extraction problem. Namely, we consider the multi-sweeps of a vehicle as elements composing a set and infer the set feature, which is an optimal estimation of the 3D shape described in the abstract implicit space. In particular, we present a theoretical analysis of multi-sweep consistency and complementarity in the latent feature space. Guided by this analysis, we design a new architecture to optimally estimate the Signed Distance Function shape of a vehicle from its in-the-wild multi-sweep point clouds. Qualitative and quantitative evaluations on both real-world and synthetic datasets show the superiority of our approach over the state-of-the-art methods." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 587, + 545, + 635 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 587, + 545, + 635 + ], + "spans": [ + { + "bbox": [ + 304, + 587, + 545, + 635 + ], + "type": "text", + "content": "Limitation. Despite promising results, our approach still relies on a synthetic 3D dataset to gain prior knowledge of 3D shapes for reconstruction. Exploring reconstruction by learning directly from real data is worthy of further study." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 646, + 403, + 658 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 646, + 403, + 658 + ], + "spans": [ + { + "bbox": [ + 306, + 646, + 403, + 658 + ], + "type": "text", + "content": "Acknowledgments" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "text", + "content": "The authors gratefully acknowledge the support of MindSpore, CANN, and Ascend AI Processor. The authors would also like to thank Andrew Yang and Hunter Schofield for their assistance." + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "8314" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 286, + 712 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 53, + 91, + 286, + 145 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 286, + 145 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 286, + 145 + ], + "type": "text", + "content": "[1] Dejan Azinović, Ricardo Martin-Brualla, Dan B Goldman, Matthias Nießner, and Justus Thies. Neural rgb-d surface reconstruction. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6290-6301, 2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 148, + 286, + 180 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 148, + 286, + 180 + ], + "spans": [ + { + "bbox": [ + 53, + 148, + 286, + 180 + ], + "type": "text", + "content": "[2] Heli Ben-Hamu, Haggai Maron, Itay Kezurer, Gal Avineri, and Yaron Lipman. Multi-chart generative surface modeling. ACM Transactions on Graphics, 37(6):1-15, 2018." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 182, + 286, + 216 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 182, + 286, + 216 + ], + "spans": [ + { + "bbox": [ + 53, + 182, + 286, + 216 + ], + "type": "text", + "content": "[3] Paul J Besl and Neil D McKay. Method for registration of 3-d shapes. In Sensor fusion IV: control paradigms and data structures, volume 1611, pages 586-606. Spie, 1992." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 217, + 286, + 261 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 217, + 286, + 261 + ], + "spans": [ + { + "bbox": [ + 53, + 217, + 286, + 261 + ], + "type": "text", + "content": "[4] Hongrui Cai, Wanquan Feng, Xuetao Feng, Yan Wang, and Juyong Zhang. Neural surface reconstruction of dynamic scenes with monocular rgb-d camera. In Proc. of Conference on Neural Information Processing Systems, 2022." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 262, + 286, + 317 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 262, + 286, + 317 + ], + "spans": [ + { + "bbox": [ + 53, + 262, + 286, + 317 + ], + "type": "text", + "content": "[5] Yingjie Cai, Kwan-Yee Lin, Chao Zhang, Qiang Wang, Xiaogang Wang, and Hongsheng Li. Learning a structured latent space for unsupervised point cloud completion. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5543-5553, 2022." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 319, + 286, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 319, + 286, + 374 + ], + "spans": [ + { + "bbox": [ + 53, + 319, + 286, + 374 + ], + "type": "text", + "content": "[6] Rohan Chabra, Jan E Lenssen, Eddy Ilg, Tanner Schmidt, Julian Straub, Steven Lovegrove, and Richard Newcombe. Deep local shapes: Learning local sdf priors for detailed 3d reconstruction. In Proc. of European Conference on Computer Vision, pages 608-625. Springer, 2020." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 376, + 286, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 376, + 286, + 430 + ], + "spans": [ + { + "bbox": [ + 53, + 376, + 286, + 430 + ], + "type": "text", + "content": "[7] Angel X Chang, Thomas Funkhouser, Leonidas Guibas, Pat Hanrahan, Qixing Huang, Zimo Li, Silvio Savarese, Manolis Savva, Shuran Song, Hao Su, et al. Shapenet: An information-rich 3d model repository. arXiv preprint arXiv:1512.03012, 2015." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 432, + 286, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 432, + 286, + 487 + ], + "spans": [ + { + "bbox": [ + 53, + 432, + 286, + 487 + ], + "type": "text", + "content": "[8] Angela Dai, Angel X Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 5828-5839, 2017." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 489, + 286, + 543 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 489, + 286, + 543 + ], + "spans": [ + { + "bbox": [ + 53, + 489, + 286, + 543 + ], + "type": "text", + "content": "[9] Angela Dai, Christian Diller, and Matthias Nießner. Sg-nn: Sparse generative neural networks for self-supervised scene completion of rgb-d scans. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 849–858, 2020." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 545, + 286, + 599 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 545, + 286, + 599 + ], + "spans": [ + { + "bbox": [ + 48, + 545, + 286, + 599 + ], + "type": "text", + "content": "[10] Angela Dai, Charles Ruizhongtai Qi, and Matthias Nießner. Shape completion using 3d-encoder-predictor cnns and shape synthesis. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 5868-5877, 2017." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 601, + 286, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 601, + 286, + 646 + ], + "spans": [ + { + "bbox": [ + 48, + 601, + 286, + 646 + ], + "type": "text", + "content": "[11] Yueqi Duan, Haidong Zhu, He Wang, Li Yi, Ram Nevata, and Leonidas J Guibas. Curriculum deepsdf. In Proc. of European Conference on Computer Vision, pages 51-67. Springer, 2020." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 647, + 286, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 286, + 712 + ], + "type": "text", + "content": "[12] Shivam Duggal, Zihao Wang, Wei-Chiu Ma, Sivabalan Manivasagam, Justin Liang, Shenlong Wang, and Raquel Urtasun. Mending neural implicit modeling for 3d vehicle reconstruction in the wild. In Proc. of IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1900-1909, 2022." + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "text", + "content": "[13] Francis Engelmann, Jörg Stuckler, and Bastian Leibe. Samp: shape and motion priors for 4d vehicle reconstruction. In Proc. of IEEE Winter Conference on Applications of Computer Vision, pages 400-408. IEEE, 2017." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 118, + 545, + 171 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 545, + 171 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 545, + 171 + ], + "type": "text", + "content": "[14] Qiaojun Feng, Yue Meng, Mo Shan, and Nikolay Atanasov. Localization and mapping using instance-specific mesh models. In Proc. of IEEE/RSJ International Conference on Intelligent Robots and Systems, pages 4985-4991. IEEE, 2019." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 172, + 545, + 215 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 172, + 545, + 215 + ], + "spans": [ + { + "bbox": [ + 307, + 172, + 545, + 215 + ], + "type": "text", + "content": "[15] Andreas Geiger, Philip Lenz, Christoph Stiller, and Raquel Urtasun. Vision meets robotics: The kitti dataset. The International Journal of Robotics Research, 32(11):1231-1237, 2013." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 217, + 545, + 270 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 217, + 545, + 270 + ], + "spans": [ + { + "bbox": [ + 307, + 217, + 545, + 270 + ], + "type": "text", + "content": "[16] Thibault Groueix, Matthew Fisher, Vladimir G Kim, Bryan C Russell, and Mathieu Aubry. A papier-mâché approach to learning 3d surface generation. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 216-224, 2018." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 272, + 545, + 326 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 272, + 545, + 326 + ], + "spans": [ + { + "bbox": [ + 307, + 272, + 545, + 326 + ], + "type": "text", + "content": "[17] Jiayuan Gu, Wei-Chiu Ma, Sivabalan Manivasagam, Wenyuan Zeng, Zihao Wang, Yuwen Xiong, Hao Su, and Raquel Urtasun. Weakly-supervised 3d shape completion in the wild. In Proc. of European Conference on Computer Vision, pages 283-299. Springer, 2020." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 327, + 545, + 369 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 327, + 545, + 369 + ], + "spans": [ + { + "bbox": [ + 307, + 327, + 545, + 369 + ], + "type": "text", + "content": "[18] Timo Hackel, Nikolay Savinov, Lubor Ladicky, Jan D Wegner, Konrad Schindler, and Marc Pollefeys. Semantic3d. net: A new large-scale point cloud classification benchmark. arXiv preprint arXiv:1704.03847, 2017." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 371, + 545, + 425 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 371, + 545, + 425 + ], + "spans": [ + { + "bbox": [ + 307, + 371, + 545, + 425 + ], + "type": "text", + "content": "[19] Tao Hu, Zhizhong Han, Abhinav Shrivastava, and Matthias Zwicker. Render4completion: Synthesizing multi-view depth maps for 3d shape completion. In Proc. of the IEEE/CVF International Conference on Computer Vision Workshops, pages 0–0, 2019." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 426, + 545, + 445 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 426, + 545, + 445 + ], + "spans": [ + { + "bbox": [ + 307, + 426, + 545, + 445 + ], + "type": "text", + "content": "[20] Huawei. Mindspace. https://www.mindspore.cn/, 2020." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 449, + 545, + 480 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 449, + 545, + 480 + ], + "spans": [ + { + "bbox": [ + 307, + 449, + 545, + 480 + ], + "type": "text", + "content": "[21] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. In Proc. of the International Conference on Learning Representations (Poster), 2015." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 482, + 545, + 534 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 482, + 545, + 534 + ], + "spans": [ + { + "bbox": [ + 307, + 482, + 545, + 534 + ], + "type": "text", + "content": "[22] Chen Kong, Chen-Hsuan Lin, and Simon Lucey. Using locally corresponding cad models for dense 3d reconstructions from a single image. In Proc. the IEEE conference on computer vision and pattern recognition, pages 4857-4865, 2017." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 536, + 545, + 568 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 536, + 545, + 568 + ], + "spans": [ + { + "bbox": [ + 307, + 536, + 545, + 568 + ], + "type": "text", + "content": "[23] Chenqi Li, Yuan Ren, and Bingbing Liu. Pcgen: Point cloud generator for lidar simulation. In Proc. of International Conference on Robotics and Automation, 2023." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 570, + 545, + 601 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 570, + 545, + 601 + ], + "spans": [ + { + "bbox": [ + 307, + 570, + 545, + 601 + ], + "type": "text", + "content": "[24] William E Lorensen and Harvey E Cline. Marching cubes: A high resolution 3d surface construction algorithm. ACM siggraph computer graphics, 21(4):163-169, 1987." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 603, + 545, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 603, + 545, + 645 + ], + "spans": [ + { + "bbox": [ + 307, + 603, + 545, + 645 + ], + "type": "text", + "content": "[25] Shirui Luo, Changqing Zhang, Wei Zhang, and Xiaochun Cao. Consistent and specific multi-view subspace clustering. In Proc. of the AAAI conference on artificial intelligence, volume 32, 2018." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 647, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 647, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 307, + 647, + 545, + 689 + ], + "type": "text", + "content": "[26] Xiaoxu Meng, Weikai Chen, and Bo Yang. Neat: Learning neural implicit surfaces with arbitrary topologies from multi-view images. Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, June 2023." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 691, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 691, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 691, + 545, + 712 + ], + "type": "text", + "content": "[27] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks:" + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8315" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 66, + 72, + 288, + 105 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 288, + 105 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 288, + 105 + ], + "type": "text", + "content": "Learning 3d reconstruction in function space. In Proc. of IEEE Conf. on Computer Vision and Pattern Recognition, 2019." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 287, + 151 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 287, + 151 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 287, + 151 + ], + "type": "text", + "content": "[28] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 152, + 288, + 218 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 152, + 288, + 218 + ], + "spans": [ + { + "bbox": [ + 48, + 152, + 288, + 218 + ], + "type": "text", + "content": "[29] Richard A Newcombe, Shahram Izadi, Otmar Hilliges, David Molyneaux, David Kim, Andrew J Davison, Pushmeet Kohi, Jamie Shotton, Steve Hodges, and Andrew Fitzgibbon. Kinectfusion: Real-time dense surface mapping and tracking. In Proc. IEEE international symposium on mixed and augmented reality, pages 127-136. Ieee, 2011." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 220, + 287, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 220, + 287, + 274 + ], + "spans": [ + { + "bbox": [ + 48, + 220, + 287, + 274 + ], + "type": "text", + "content": "[30] Liang Pan, Tong Wu, Zhongang Cai, Ziwei Liu, Xumin Yu, Yongming Rao, Jiwen Lu, Jie Zhou, Mingye Xu, Xiaoyuan Luo, et al. Multi-view partial (mvp) point cloud challenge 2021 on completion and registration: Methods and results. arXiv preprint arXiv:2112.12053, 2021." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 276, + 288, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 276, + 288, + 330 + ], + "spans": [ + { + "bbox": [ + 48, + 276, + 288, + 330 + ], + "type": "text", + "content": "[31] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. Deepsdf: Learning continuous signed distance functions for shape representation. In Proc. of the IEEE/CVF conference on computer vision and pattern recognition, pages 165-174, 2019." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 331, + 287, + 376 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 331, + 287, + 376 + ], + "spans": [ + { + "bbox": [ + 48, + 331, + 287, + 376 + ], + "type": "text", + "content": "[32] Charles R Qi, Hao Su, Kaichun Mo, and Leonidas J Guibas. Pointnet: Deep learning on point sets for 3d classification and segmentation. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 652-660, 2017." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 377, + 287, + 421 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 377, + 287, + 421 + ], + "spans": [ + { + "bbox": [ + 48, + 377, + 287, + 421 + ], + "type": "text", + "content": "[33] Charles Ruizhongtai Qi, Li Yi, Hao Su, and Leonidas J Guibas. Pointnet++: Deep hierarchical feature learning on point sets in a metric space. Advances in neural information processing systems, 30, 2017." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 422, + 288, + 465 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 422, + 288, + 465 + ], + "spans": [ + { + "bbox": [ + 48, + 422, + 288, + 465 + ], + "type": "text", + "content": "[34] Radu Bogdan Rusu, Nico Blodow, and Michael Beetz. Fast point feature histograms (fpfh) for 3d registration. In Proc. of IEEE international conference on robotics and automation, pages 3212-3217. IEEE, 2009." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 467, + 287, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 467, + 287, + 521 + ], + "spans": [ + { + "bbox": [ + 48, + 467, + 287, + 521 + ], + "type": "text", + "content": "[35] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5459-5469, 2022." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 523, + 288, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 523, + 288, + 588 + ], + "spans": [ + { + "bbox": [ + 48, + 523, + 288, + 588 + ], + "type": "text", + "content": "[36] Pei Sun, Henrik Kretzschmar, Xerxes Dotiwalla, Aurelien Chouard, Vijaysai Patnaik, Paul Tsui, James Guo, Yin Zhou, Yuning Chai, Benjamin Caine, et al. Scalability in perception for autonomous driving: Waymo open dataset. In Proc. of the IEEE/CVF conference on computer vision and pattern recognition, pages 2446-2454, 2020." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 590, + 287, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 590, + 287, + 643 + ], + "spans": [ + { + "bbox": [ + 48, + 590, + 287, + 643 + ], + "type": "text", + "content": "[37] Shubham Tulsiani, Alexei A Efros, and Jitendra Malik. Multi-view consistency as supervisory signal for learning shape and pose prediction. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 2897-2905, 2018." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 646, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 646, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 646, + 287, + 689 + ], + "type": "text", + "content": "[38] Nitika Verma, Edmond Boyer, and Jakob Verbeek. Feastnet: Feature-steered graph convolutions for 3d shape analysis. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 2598-2606, 2018." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "text", + "content": "[39] Dan Wang, Xinrui Cui, Xun Chen, Zhengxia Zou, Tianyang Shi, Septimiu Salcudean, Z Jane Wang, and Rabab Ward." + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 643 + ], + "type": "list", + "angle": 0, + "index": 26, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "type": "text", + "content": "Multi-view 3d reconstruction with transformers. In Proc. of the IEEE/CVF International Conference on Computer Vision, pages 5722-5731, 2021." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "type": "text", + "content": "[40] Nanyang Wang, Yinda Zhang, Zhuwen Li, Yanwei Fu, Wei Liu, and Yu-Gang Jiang. Pixel2mesh: Generating 3d mesh models from single rgb images. In Proc. of the European conference on computer vision, pages 52-67, 2018." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 152, + 545, + 195 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 195 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 195 + ], + "type": "text", + "content": "[41] Peng Wang, Lingjie Liu, Yuan Liu, Christian Theobalt, Taku Komura, and Wenping Wang. Neus: Learning neural implicit surfaces by volume rendering for multi-view reconstruction. arXiv preprint arXiv:2106.10689, 2021." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 197, + 545, + 240 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 197, + 545, + 240 + ], + "spans": [ + { + "bbox": [ + 307, + 197, + 545, + 240 + ], + "type": "text", + "content": "[42] Xiaogang Wang, Marcelo H Ang, and Gim Hee Lee. Voxel-based network for shape completion by leveraging edge generation. In Proc. of the IEEE/CVF international conference on computer vision, pages 13189-13198, 2021." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 241, + 545, + 296 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 241, + 545, + 296 + ], + "spans": [ + { + "bbox": [ + 307, + 241, + 545, + 296 + ], + "type": "text", + "content": "[43] Haozhe Xie, Hongxun Yao, Shangchen Zhou, Jiageng Mao, Shengping Zhang, and Wenxiu Sun. Grnet: Gridding residual network for dense point cloud completion. In Proc. of the European conference on computer vision, pages 365-381. Springer, 2020." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 297, + 545, + 351 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 297, + 545, + 351 + ], + "spans": [ + { + "bbox": [ + 307, + 297, + 545, + 351 + ], + "type": "text", + "content": "[44] Qiangeng Xu, Zexiang Xu, Julien Philip, Sai Bi, Zhixin Shu, Kalyan Sunkavalli, and Ulrich Neumann. Point-nerf: Point-based neural radiance fields. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5438-5448, 2022." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 353, + 545, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 353, + 545, + 407 + ], + "spans": [ + { + "bbox": [ + 307, + 353, + 545, + 407 + ], + "type": "text", + "content": "[45] Jianglong Ye, Yuntao Chen, Naiyan Wang, and Xiaolong Wang. Gifs: Neural implicit function for general shape representation. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12829-12839, 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 409, + 545, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 409, + 545, + 453 + ], + "spans": [ + { + "bbox": [ + 307, + 409, + 545, + 453 + ], + "type": "text", + "content": "[46] Jianglong Ye, Yuntao Chen, Naiyan Wang, and Xiaolong Wang. Online adaptation for implicit object tracking and shape reconstruction in the wild. IEEE Robotics and Automation Letters, 7(4):8909-8916, 2022." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 454, + 545, + 507 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 454, + 545, + 507 + ], + "spans": [ + { + "bbox": [ + 307, + 454, + 545, + 507 + ], + "type": "text", + "content": "[47] Xumin Yu, Yongming Rao, Ziyi Wang, Zuyan Liu, Jiwen Lu, and Jie Zhou. Pointr: Diverse point cloud completion with geometry-aware transformers. In Proc. of the IEEE/CVF international conference on computer vision, pages 12498-12507, 2021." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 510, + 545, + 552 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 510, + 545, + 552 + ], + "spans": [ + { + "bbox": [ + 307, + 510, + 545, + 552 + ], + "type": "text", + "content": "[48] Xumin Yu, Yongming Rao, Ziyi Wang, Jiwen Lu, and Jie Zhou. Adapointr: Diverse point cloud completion with adaptive geometry-aware transformers. arXiv preprint arXiv:2301.04545, 2023." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 554, + 545, + 597 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 554, + 545, + 597 + ], + "spans": [ + { + "bbox": [ + 307, + 554, + 545, + 597 + ], + "type": "text", + "content": "[49] Wentao Yuan, Tejas Khot, David Held, Christoph Mertz, and Martial Hebert. Pcn: Point completion network. In Proc. of International Conference on 3D Vision, pages 728-737, 2018." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 599, + 545, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 599, + 545, + 643 + ], + "spans": [ + { + "bbox": [ + 307, + 599, + 545, + 643 + ], + "type": "text", + "content": "[50] Changqing Zhang, Zongbo Han, Huazhu Fu, Joey Tianyi Zhou, Qinghua Hu, et al. Cpm-nets: Cross partial multiview networks. Advances in Neural Information Processing Systems, 32, 2019." + } + ] + } + ], + "index": 25 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "8316" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/59188c7c-19e6-4a92-b752-2ffcc7690379_content_list.json b/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/59188c7c-19e6-4a92-b752-2ffcc7690379_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..107ad1164cab1215ee5eb82e8b2b6427b681d060 --- /dev/null +++ b/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/59188c7c-19e6-4a92-b752-2ffcc7690379_content_list.json @@ -0,0 +1,1505 @@ +[ + { + "type": "text", + "text": "MV-Map: Offboard HD Map Generation with Multi-view Consistency", + "text_level": 1, + "bbox": [ + 129, + 130, + 839, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Ziyang Xie\\*1,2 Ziqi Pang\\*1 Yu-Xiong Wang $^{1}$ $^{1}$ University of Illinois Urbana-Champaign $^{2}$ Fudan University \n{ziyang8, ziqip2, yxw}@illinois.edu", + "bbox": [ + 223, + 179, + 746, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 268, + 313, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "While bird's-eye-view (BEV) perception models can be helpful in building high-definition maps (HD maps) with less human labor, their results are often unreliable and demonstrate noticeable inconsistencies in the predicted HD maps from different viewpoints. This is because BEV perception is typically set up in an \"onboard\" manner, which restricts the computation and prevents algorithms from simultaneously reasoning multiple views. This paper overcomes these limitations and advocates a more practical \"offboard\" HD map generation setup that removes the computation constraints, based on the fact that HD maps are commonly reusable infrastructures built offline in data centers. To this end, we propose a novel offboard pipeline called MV-Map that capitalizes multi-view consistency and can handle an arbitrary number of frames with the key design of a \"region-centric\" framework. In MV-Map, the target HD maps are created by aggregating all the frames of onboard predictions, weighted by the confidence scores assigned by an \"uncertainty network.\" To further enhance multi-view consistency, we augment the uncertainty network with the global 3D structure optimized by a voxelized neural radiance field (Voxel-NeRF). Extensive experiments on nuScenes show that our MV-Map significantly improves the quality of HD maps, further highlighting the importance of offboard methods for HD map generation. Our code and model are available at https://github.com/ZiYang-xie/MV-Map.", + "bbox": [ + 76, + 301, + 473, + 709 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 741, + 209, + 756 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "High-definition maps (HD maps) play a crucial role in ensuring the safe navigation of autonomous vehicles, by providing essential positional and semantic information about road elements. Ideally, one would expect the process of constructing HD maps to be as simple as collecting numerous sensory data while driving and then utilizing an automatic algorithm to extract the road elements,", + "bbox": [ + 75, + 767, + 468, + 875 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/d6e579133b4ba25187e6ef94d00293d806862783f46e358bdcd855b6214fe12d.jpg", + "image_caption": [ + "Figure 1: Current onboard methods generate unreliable HD map predictions that are inconsistent across multiple views, due to occlusions or viewpoint changes. By contrast, our offboard pipeline constructs a unified and multi-view consistent HD map with clearer lanes. Our key design is a region-centric framework that aggregates single-frame information for each target HD map region." + ], + "image_footnote": [], + "bbox": [ + 506, + 268, + 888, + 445 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "as illustrated in Fig. 1. However, the mainstream solutions generally involve human annotators, as seen in widely-used datasets [3, 4, 8, 39]. This design is based on the consideration of the infrastructure role and high re-usability of HD maps, which can serve autonomous vehicles for virtually infinite times after a single construction process before any environmental changes. Even so, the expense of manual annotation obstructs the expansion of autonomous driving to new locations, and we aim to develop reliable algorithms that can decrease or replace the need for human labor in HD map construction.", + "bbox": [ + 496, + 579, + 892, + 744 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Towards this goal, there have been recent attempts that automatically generate HD maps using bird's-eye-view (BEV) perception [11, 13, 15]. However, their results are often unreliable, as illustrated by noticeable inconsistencies in the predicted HD maps from different viewpoints (a representative example is in Fig. 1). We argue that multi-view consistency is an intrinsic property of HD maps, because the rigid and static HD maps shouldn't change significantly after simply switching viewpoints. The violations of consistency arise from the fact that existing BEV perception", + "bbox": [ + 496, + 750, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "* Equal contribution.", + "bbox": [ + 94, + 886, + 205, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "8658", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/37ba0b646d97a46811ffa293b1afa6d51c06d8788d81fe62c60951f31aabc4b1.jpg", + "image_caption": [ + "Figure 2: Our Voxel-NeRF reconstructs high-quality 3D structure of the scene. As in the rendering result, the lanes and pedestrian crossings (highlighted) are clear." + ], + "image_footnote": [], + "bbox": [ + 86, + 89, + 467, + 186 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "algorithms do not account for all the views explicitly and thus do not align their predictions. This issue further boils down to their onboard setting, where the models are only allowed to access computing devices onboard in autonomous vehicles and can only handle a single frame or a few neighboring frames.", + "bbox": [ + 75, + 262, + 467, + 353 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Given such limitations of the onboard setup, we underline a critical yet under-explored offboard setup that removes the computation constraints. Our offboard setting aligns well with the infrastructure role of HD maps: constructing HD maps can and should utilize powerful data centers to maximize the fidelity of predictions, thus ensuring the safety and reliability of the virtually infinite usages of HD maps. By aggregating information from diverse viewpoints and enhancing consistency, our offboard generation provides a natural improvement. As shown in Fig. 1, having multiple views of a shared region offers richer geometric and semantic cues, as well as improves the completeness of scene understanding, particularly regarding frequent occlusions in urban traffic.", + "bbox": [ + 75, + 354, + 467, + 565 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "With HD map construction primarily relying on vision information to infer the semantics, which is different from the previous offboard studies depending on point clouds, we are the first to explore a vision-oriented offboard perception framework to our best knowledge. To this end, we propose Multi-view Map (MV-Map) that leverages information from every frame's viewpoint and generates a unified HD map consistent with all of them. In contrast to the frame-centric design in current onboard methods that merges a fixed number of frames on the input level, we propose a region-centric design inspired by \"offboard 3D detection\" [30] to fully utilize the data from diverse views. Notably, our design can connect every HD map region with an arbitrary number of input frames covering its area. The pipeline of our framework involves extracting all the HD map patches predicted by an off-the-shelf onboard model related to that HD map region, and then fusing the patches into a final result that agrees with all the views, as illustrated in the arrows in Fig. 1. To give more weight to reliable frames, such as those with a clear view of the target region, we introduce an \"uncertainty network\" as a key component, which assigns confidence scores to onboard results and performs a weighted", + "bbox": [ + 75, + 568, + 468, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "average of HD map patches guided by the confidence.", + "bbox": [ + 498, + 90, + 854, + 106 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We further enhance the consensus among all the frames by augmenting the uncertainty network with cross-view consistency information. Our key insight is to learn a coherent 3D structure from diverse views and provide it as an auxiliary input to the uncertainty network. For this purpose, we exploit neural radiance fields (NeRFs) [22], a state-of-the-art approach that represents 3D structures of scenes. As shown in Fig. 2, our NeRF model synthesizes a high-quality scene structure. Compared with alternative 3D reconstruction strategies like structure from motion (e.g., COLMAP [34]), NeRF is more preferred from a practical perspective, because its runtime grows linearly with the frame number, whereas COLMAP increases quadratically. Moreover, NeRF is fully self-supervised and does not require additional annotations, unlike multi-view stereo methods such as MVSNet [44]. To improve the scalability of NeRF, we leverage a voxelized variant of NeRF (VoxelNeRF) to promote efficiency and propose loss functions that implicitly guide the concentration of NeRF on the near-ground geometry related to HD map generation. Additionally, we highlight NeRF's flexibility and scalability to an arbitrary number of views, making it critical in offboard HD map generation.", + "bbox": [ + 496, + 108, + 890, + 455 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To summarize, we make the following contributions:", + "bbox": [ + 517, + 455, + 867, + 470 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1. We are the first to study the problem of learning to generate HD maps offboard, and we are also the first vision-oriented offboard study to our best knowledge.", + "2. We propose an effective region-centric framework MV-Map that can generate a multi-view consistent HD map from an arbitrarily large number of frames.", + "3. We introduce and extend Voxel-NeRF to encode the 3D structure from all frames for HD map generation tasks, further guiding the fusion for multi-view consistency." + ], + "bbox": [ + 500, + 473, + 890, + 609 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Large-scale experiments on nuScenes [3] show that MV-Map significantly improves HD map quality. Notably, MV-Map can effectively utilize an increasing number of input frames, making it attractive for real-world applications.", + "bbox": [ + 498, + 609, + 890, + 671 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 688, + 640, + 704 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Offboard 3D perception. The need for large-volume training data encourages developing offboard algorithms. Existing studies mainly focus on predicting 3D bounding boxes [24, 28, 30, 43]. The most representative work on \"offboard 3D detection\" [30] extracts multi-frame point clouds in object tracks and refines the 3D bounding boxes with the \"4D\" data. Its success heavily relies on the absolute 3D positions of point clouds, where simply overlaying Li-DAR points can construct denser surfaces of objects. However, in HD map generation that relies on images, it is not straightforward to accumulate imagery data in the 3D space. To overcome this limitation, we propose region-centric fu", + "bbox": [ + 496, + 719, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "8659", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "sion to aggregate multi-frame information and utilize multiview reconstruction, e.g. NeRF, to encode global geometry. Our study is also the first vision-oriented offboard pipeline.", + "bbox": [ + 76, + 90, + 468, + 137 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "BEV segmentation and HD map construction. Onboard HD map construction is closely related to BEV segmentation, as in HDMapNet [13]. The major challenge in BEV segmentation is to map the image features to the 3D world. The conventional approach leverages inverse perspective warping [1, 2, 6, 27, 31]. BEV perception methods either apply attention to capture the transformation [15, 19], incorporate depth information [12, 14, 26, 29], or directly query the features from voxels [11]. To better support downstream applications, some recent methods [16, 18] have developed special decoders to generate vectorized HD maps. Unlike these onboard methods, our proposition is a general offboard pipeline that utilizes any off-the-shelf segmentation models as an internal component and refines its results with multi-view consistent fusion. In this sense, neural map prior [41] and NeMO [47] also propose to perform long-term temporal fusion, but they primarily focus on an onboard setting and cannot fully leverage the multi-view consistency from long video sequences. Compared with them, our MV-Map is an offboard framework and explicitly accounts for the geometry of diverse views by reconstructing the 3D structure of the scene.", + "bbox": [ + 76, + 140, + 472, + 473 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Neural radiance fields. NeRF [22] has shown outstanding capability in 3D reconstruction. Recent work [20, 32, 37, 40] has extended NeRF into large unbounded scenes, such as city-scale NeRF with ego-centric camera settings [32, 37, 40] and improvement from depth-supervised methods [5, 25, 38, 42]. With NeRF's ability to optimize 3D structures from numerous views, it becomes an ideal method to enforce multi-view consistency for offboard perception. However, as we are the first to adapt NeRF for HD map generation, some important modifications are made. First, we adopt voxel-based NeRF [10, 17, 23, 35, 36] to accelerate the NeRF training by voxelizing the space and encoding the parameters for each position in the voxels. This allows us to reconstruct a huge scene from nuScenes within minutes. In addition, we propose a \"total-variance loss\" to enhance NeRF's concentration on the near-ground geometry, which also reflects the shift of concentration from pixel quality to downstream HD map generation.", + "bbox": [ + 76, + 477, + 472, + 765 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Offboard HD Map Generation", + "text_level": 1, + "bbox": [ + 76, + 779, + 359, + 797 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Given a sequence of sensory data, the goal of HD map generation is to predict the positions and semantics of road elements in the BEV space, including road dividers, road boundaries, and pedestrian crossings.", + "bbox": [ + 76, + 806, + 468, + 867 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Problem statement. We consider the input of HD map generation as $\\mathcal{D} = \\{(I_i, P_i)\\}_{i=1}^N$ , where $I_i$ denotes the $i$ -th", + "bbox": [ + 76, + 869, + 468, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "sensor frame, $P_{i}$ is the set of associated sensor poses, and $N$ is the total number of frames in the database representing diverse views of a scene captured by a moving ego vehicle. The output is denoted as $\\mathcal{M} = \\{M_i\\}_{i=1}^N$ , where $M_{i}$ is the HD map for the region nearby the ego vehicle on frame $i$ . Following HDMapNet [13], we define $M_{i}$ as a local semantic map on BEV. Note that the aforementioned formulation is agnostic to sensor types. In the main paper, we mainly focus on vision-oriented HD map generation, and we extend it to leveraging additional LiDAR data in Sec. 5.6. Specifically, every frame $I_{i}$ contains $K = 6$ RGB images $\\{I_{i,j}\\}_{j=1}^{K}$ on nuScenes [3], and $P_{i} = \\{P_{i,j}\\}_{j=1}^{K}$ comprises of the intrinsic and extrinsic matrices of corresponding cameras.", + "bbox": [ + 496, + 90, + 890, + 289 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Offboard vs. onboard settings. Compared with the conventional onboard setup, our offboard setup offers greater flexibility in terms of speed and computation resources. Onboard HD map generation algorithms are often constrained by efficiency requirements and cannot use all the $N$ frames in a single run. By contrast, offboard algorithms are allowed to have access to all the $N$ frames, and can then leverage the offline setting and abundant computation resources to generate HD maps of higher quality.", + "bbox": [ + 496, + 292, + 892, + 430 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "From frame-centric to region-centric designs. There are different strategies to utilize the temporal data from $N$ frames, similar to offboard 3D detection [30]. A direct solution is frame-centric [30], in which we naively increase the number of frames for existing onboard HD map construction methods, typically BEV segmentation models, and extend them to long sequences. While previous work [13, 15] has illustrated the benefit of longer temporal horizons, a multi-frame BEV segmentation model can only handle a fixed number of input frames, and increasing the frame number requires a linear growth in GPU capacity. Therefore, simply scaling up the input frames of existing onboard models is not an effective way of exploiting the offboard data, which often have varying and large frame numbers.", + "bbox": [ + 496, + 433, + 892, + 645 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To overcome the limitations of the frame-centric design, we propose a novel region-centric design that adaptively aggregates information from an arbitrary number of available frames for each HD map region. Our design is inspired by the object-centric notion in 3D detection [30], but extends to the task of HD map construction. Doing so enables the consensus across frames captured from different viewpoints.", + "bbox": [ + 496, + 645, + 890, + 751 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4. Method: Multi-view Map", + "text_level": 1, + "bbox": [ + 500, + 765, + 738, + 784 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Overview. Fig. 3 illustrates the overall framework of our Multi-view Map (MV-Map). An onboard HD map model processes every frame $(I_i, P_i)$ and generates its corresponding BEV feature map $F_i$ and HD map semantics $S_i$ (Sec. 4.1). Then, an uncertainty network assesses the reliability of the single-frame information $F_i$ for every region on the HD map (Sec. 4.2). Meanwhile, a voxelized NeRF", + "bbox": [ + 496, + 794, + 892, + 902 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "8660", + "bbox": [ + 482, + 944, + 516, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/95d95c64fca981a4691a46e46e3f4e5446098ce12c95f0d9c648c73e57cf5db6.jpg", + "image_caption": [ + "Figure 3: Offboard pipeline of MV-Map. Given an arbitrary number of input frames, MV-Map first leverages an off-the-shelf onboard model to generate BEV features and semantic maps for each frame. Then an uncertainty network predicts their corresponding confidence maps and guides the region-centric aggregation of a unified HD map. Our pipeline further develops a Voxel-NeRF tailored to 3D structures related to HD maps to augment MV-Map with multi-view geometry." + ], + "image_footnote": [], + "bbox": [ + 143, + 88, + 823, + 270 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "$f_{\\mathrm{NeRF}}$ optimizes a global 3D structure from all $N$ frames and provides multi-view consistency information to the uncertainty network (Sec. 4.3). The final prediction for every region on the HD map is produced by a weighted average of the single-frame semantics $S_{i}$ , which enables handling an arbitrary number of frames.", + "bbox": [ + 75, + 353, + 472, + 445 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Onboard Model", + "text_level": 1, + "bbox": [ + 76, + 455, + 238, + 469 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The onboard model is the entry point of our pipeline. Most existing HD map generation methods follow an encoder-decoder design. The encoder generates a BEV feature map $F_{i}$ from the input $(I_i, P_i)$ as $\\mathsf{Encoder}(I_i, P_i) \\to F_i$ , and the decoder converts the feature map $F_{i}$ into a semantic map $S_{i}$ as $\\mathsf{Decoder}(F_i) \\to S_i$ .", + "bbox": [ + 75, + 478, + 468, + 569 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Since our pipeline only requires the BEV feature map $F_{i}$ to activate the subsequent modules, MV-Map is agnostic to specific encoder-decoder designs. Without the loss of generality, we mainly adopt the encoder in SimpleBEV [11] and use a lightweight convolutional decoder. Results based on additional models are in Table D (Supplementary).", + "bbox": [ + 75, + 570, + 470, + 661 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Encoder. For each frame, a convolutional backbone first converts $K$ images $\\{I_{i,j}\\}_{j = 1}^{K}$ into 2D image feature maps $\\{F_{i,j}^{2\\mathrm{D}}\\}_{j = 1}^{K}$ . The features are then lifted into the 3D world, through a set of voxels that are pre-defined by the encoder with shape $X\\times Y\\times Z$ centered around the ego vehicle: the 2D features are bi-linearly sampled for every voxel based on their projected locations on the images, leading to a voxelized 3D feature map $F_{i}^{3\\mathrm{D}}$ . Finally, reducing the Z-axis of $F_{i}^{3\\mathrm{D}}$ produces a BEV feature map $F_{i}$ with shape $X\\times Y\\times C$ , where $C$ is the feature dimension.", + "bbox": [ + 76, + 664, + 470, + 816 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Decoder. Our decoder is a fully-convolutional segmentation head that predicts the logits of semantics from every BEV grid in $F_{i}$ . It generates the surrounding HD map as the semantic segmentation result $S_{i}$ with shape $X \\times Y$ .", + "bbox": [ + 75, + 820, + 468, + 881 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Region-centric extension. Our region-centric design", + "bbox": [ + 76, + 885, + 468, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "considers each BEV grid as an HD map region. If a grid is covered in $N'$ frames, it receives $N'$ features and predictions from different viewpoints. MV-Map then fuses information from $N'$ view-specific frames to create a multi-view consistent feature for this region, detailed as below.", + "bbox": [ + 496, + 353, + 890, + 429 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.2. Global Aggregation via Uncertainty Network", + "text_level": 1, + "bbox": [ + 498, + 435, + 880, + 452 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Region-centric uncertainty-aware fusion. Our region-centric offboard pipeline learns to aggregate the $N$ frames of independent HD map predictions $\\{S_i\\}_{i=1}^N$ into a multiview consistent prediction for each region. Our key design is to introduce an uncertainty network. For the HD map predictions from all viewpoints, the uncertainty network assigns a confidence score to each BEV grid, resulting in $N \\times X \\times Y$ scores that reflect the pairwise reliability of a viewpoint contributing to an HD map region. Specifically, the uncertainty network takes the BEV features $\\{F_i\\}_{i=1}^N$ as input and generates the confidence maps $\\{C_i\\}_{i=1}^N$ , with $C_i$ of shape $X \\times Y$ . In Sec. 4.3, we will describe how we further incorporate global geometry encoded by Voxel-NeRF into the uncertainty network. The architecture of our uncertainty network is illustrated in Fig. 4, adopting a UNet-like [33] structure for predicting densely on every voxel.", + "bbox": [ + 496, + 458, + 890, + 700 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We then aggregate the per-frame semantics and confidence into a final HD map. Suppose an arbitrary target position $(x^w, y^w)$ is specified in the world coordinate system, we transform it to the local coordinate system of every frame with poses $\\{P_i\\}_{i=1}^N$ and sample the semantic maps and confidence scores at corresponding locations. Finally, the prediction for $(x^w, y^w)$ is obtained by a weighted average of per-frame semantics according to their confidence.", + "bbox": [ + 496, + 700, + 890, + 821 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "KL-divergence loss for enhanced uncertainty learning. In addition to generating confidence scores, we add a multi-layer perceptron (MLP) head to the uncertainty network to infer the KL-divergence between the predicted and ground truth semantics, as shown in Fig. 4. Intuitively, learning to", + "bbox": [ + 496, + 825, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "8661", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/0b30b1c42cc3b0917bbfad8d8486595a4bc29e5bba017992e56e89067004e97b.jpg", + "image_caption": [ + "Figure 4: Architecture of uncertainty network, which takes as input the feature map and the augmented 3D positions from NeRF for each voxel (Sec. 4.3). It outputs the confidence maps for region-centric fusion and, optionally, the predicted KL-divergence for the KL-divergence loss (detailed in Sec. 4.2)." + ], + "image_footnote": [], + "bbox": [ + 86, + 95, + 433, + 224 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "regress the KL-divergence value between the predicted and ground truth HD maps augments the confidence score of the uncertainty network, because a smaller KL-divergence value indicates better quality of map construction and the uncertainty network should assign higher confidence accordingly. During training, we encourage the inferred divergence $\\mathrm{KL}^U$ to be close to the true divergence $\\mathrm{KL}^G$ between semantics $S_{i}$ and $S_{i}$ 's ground truth, formally,", + "bbox": [ + 75, + 329, + 468, + 450 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {K L}} = \\frac {1}{X Y} \\sum_ {x = 1} ^ {X} \\sum_ {y = 1} ^ {Y} \\| \\mathrm {K L} ^ {G} [ x, y ] - \\mathrm {K L} ^ {U} [ x, y ] \\| _ {2} ^ {2}. \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 101, + 459, + 468, + 501 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We train the uncertainty network with both a cross-entropy loss between the fusion result and the ground truth semantics at each location $(x^w, y^w)$ [13] and our auxiliary KL-divergence loss in Eqn. 1. Given that the weighted average operation is differentiable, the gradients from both of the loss terms can be back-propagated to the confidence scores for updating the uncertainty network.", + "bbox": [ + 75, + 510, + 468, + 617 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.3. Voxel-NeRF for Multi-view Consistency", + "text_level": 1, + "bbox": [ + 76, + 619, + 418, + 636 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "MV-Map further leverages a voxelized NeRF to effectively construct a unified 3D structure of the scene from the $N$ frames, which is incorporated with the uncertainty network to improve the multi-view consistency of HD maps.", + "bbox": [ + 76, + 640, + 468, + 700 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Voxel-NeRF for traffic scenes. NeRF [22] represents a 3D scene as a continuous function $f_{\\mathrm{NeRF}}:(\\mathbf{x},\\theta)\\to (\\mathbf{c},\\sigma)$ , which maps every point $x$ in the 3D space to its color $c$ and density $\\sigma$ , relative to the viewing direction $\\theta$ . By explicitly encoding camera projection in the neural rendering process, the learned NeRF model $f_{\\mathrm{NeRF}}$ encodes the 3D geometry of the corresponding scene from input images. Despite the success of the vanilla NeRF, applying it to autonomous driving datasets poses significant challenges, because of the unbounded nature of the scenes and the huge quantities of data involved (e.g., 850 scenes on nuScenes [3]). Therefore, we introduce a voxelized NeRF based on DVGO [36] for better training speed and scalability. Our Voxel-NeRF captures", + "bbox": [ + 75, + 704, + 470, + 901 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "multi-view consistent geometry for outdoor scenes, instead of small objects as in conventional NeRFs. To achieve this, we initialize voxel grids with shape $X_{s} \\times Y_{s} \\times Z_{s}$ to cover the entire scene, which is larger than $X \\times Y \\times Z$ used in onboard models for single-frame areas. For each camera ray, the neural rendering operation in Voxel-NeRF concurrently queries every voxel intersected by the ray. This concurrent querying of voxels significantly accelerates the training of our Voxel-NeRF, from hours to minutes for any scene in nuScenes, enabling a reasonable computation budget for MV-Map. More details can be found in Sec. 5.", + "bbox": [ + 496, + 90, + 890, + 257 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Augmenting uncertainty network. Conceptually, the predicted semantics at a position is more reliable when it resides on the object surfaces. Once NeRF produces a multiview consistent structure, we can compute the distance between each voxel center and its closest surface. Such a clue can be exploited to evaluate the reliability of semantic maps. To this end, for an arbitrary $(x,y)$ on BEV, we first recover all the voxel center locations at the BEV coordinate $(x,y)$ as $L_{\\mathrm{Voxel}} = \\{(x,y,z_i)\\}_{i=1}^Z$ and then compute their corresponding pixel locations on the images $L_{\\mathrm{Image}} = \\{(x_i^p,y_i^p)\\}_{i=1}^Z$ . By volume rendering along the camera rays crossing these pixels, $f_{\\mathrm{NeRF}}$ reconstructs the 3D positions of these pixels, denoted as $L_{\\mathrm{NeRF}} = \\{(x_i^R,y_i^R,z_i^R)\\}_{i=1}^Z$ , which are generally the intersections between their camera rays and surfaces. (Ray casting details are in Sec. B.2 (Supplementary).) By calculating $\\Delta L_{\\mathrm{N/V}} = \\{(x_i^R - x,y_i^R - y,z_i^R - z_i)\\}_{i=1}^Z$ , we assess the consistency between voxel centers and the global 3D structure. Finally, we employ an MLP upon $\\Delta L_{\\mathrm{N/V}}$ and concatenate its output with the BEV feature, which is then used as the augmented input to the uncertainty network, which is the \"augmented 3D positions\" in Fig. 4.", + "bbox": [ + 496, + 260, + 892, + 579 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Dedicating NeRF for HD maps with total-variance loss. Note that our objective is to facilitate HD map generation, rather than optimizing rendering quality. With the majority of HD map elements situated on the ground, we modify the NeRF to focus less on the quality of pixels in the air. To this end, we introduce a simple yet effective \"total-variance loss\" that guides the optimization of near-ground geometry implicitly. This total-variance loss $\\mathcal{L}_{\\mathrm{TV}}$ is obtained by accumulating the total-variance $\\mathrm{TV}(\\cdot)$ at each BEV position:", + "bbox": [ + 498, + 580, + 888, + 717 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {T V}} = - \\frac {1}{X _ {s} Y _ {s}} \\sum_ {x = 1} ^ {X _ {s}} \\sum_ {y = 1} ^ {Y _ {s}} \\operatorname {T V} (x, y). \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 581, + 738, + 890, + 781 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Here the total-variance $\\mathrm{TV}(\\cdot)$ is defined as the L2-norm of the differences of occupancies along the Z-axis, given by", + "bbox": [ + 498, + 789, + 893, + 821 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {T V} (x, y) = \\| O [ x, y, 2: Z _ {s} ] - O [ x, y, 1: Z _ {s} - 1 ] \\| _ {2}, \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 514, + 844, + 890, + 862 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $O[x,y,z]$ represents the density of voxel $(x,y,z)$ predicted by NeRF and $\\| \\cdot \\|_2$ denotes the L2-norm.", + "bbox": [ + 496, + 869, + 890, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "8662", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/b52e6d48935f145a5619ccd3b852eed03f5e4a483c6021deb33864189440dcb0.jpg", + "table_caption": [ + "Table 1: Comparison with state-of-the-art vision-based HD map generation methods on nuScenes [3]. “*” means the results reported in HDMapNet [13]. “Average Fusion” is an offboard baseline explained in Sec. 5.2. The quantitative results indicate that our MV-Map has significant benefits to HD map generation and outperforms offboard baseline approaches." + ], + "table_footnote": [], + "table_body": "
SetupMethodmIoU (Short-range / Long-range)
DividerPed CrossingBoundaryAll
OnboardIPM(B)*25.5 / -12.1 / -27.1 / -21.6 / -
IPM(B+C)*38.6 / -19.3 / -39.3 / -32.4 / -
VPN*36.5 / -15.8 / -35.6 / -29.3 / -
Lift-Splat-Shoot [29]*38.3 / -14.9 / -39.3 / -30.8 / -
HMapNet [13]40.6 / 33.918.7 / 19.439.5 / 34.932.9 / 29.4
Onboard Model (Ours)46.4 / 39.329.7 / 26.448.1 / 39.141.4 / 35.0
OffboardAverage Fusion48.86 / 42.8331.55 / 24.7551.98 / 43.9144.13 / 37.16
MV-Map (Ours)50.87 / 48.1534.52 / 33.3455.64 / 50.2847.01 / 43.92
", + "bbox": [ + 200, + 138, + 767, + 284 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We emphasize the \"negative\" sign in Eqn. 2. It indicates \"maximizing\" the variance, because an accurate ground plane has a peak distribution of voxel occupancy on the Z-axis instead of a uniform one. TV-loss enables Voxel-NeRF to assign larger densities to the ground plane than transient objects, leading to high-quality 3D structures as in Fig. 2.", + "bbox": [ + 75, + 295, + 470, + 387 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.4. Training and Inference", + "text_level": 1, + "bbox": [ + 76, + 401, + 290, + 417 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The procedure of our offboard pipeline follows three steps: (1) we adopt an existing onboard model, (2) train Voxel-NeRF on sequences, and (3) train and infer the uncertainty network. We describe these steps in order and leave detailed configurations in Sec. G (Supplementary).", + "bbox": [ + 75, + 424, + 468, + 501 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Onboard model. As MV-Map is agnostic to the choice of onboard models (Sec. 4.1), here we adopt an off-the-shelf BEV segmentation model and freeze its parameters during both training and inference stages of the offboard pipeline.", + "bbox": [ + 75, + 506, + 470, + 569 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Voxel-NeRF. We train the Voxel-NeRF for all sequences in our training and validation datasets, using both conventional photometric loss and our total-variance loss (Sec. 4.3). Note that our NeRF training is entirely self-supervised and does not require any annotations.", + "bbox": [ + 75, + 573, + 468, + 650 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Uncertainty network. The region-centric design enables the uncertainty network to handle varying frame numbers of offboard data. In practice, however, the GPU capacities and batching during training limit the network to a fixed and restricted frame number. To overcome this issue, we adopt the solution from video-based tasks (e.g., 2D multi-object tracking [21, 46]), where models are trained on short video clips but are inferred iteratively on unbounded sequences.", + "bbox": [ + 75, + 656, + 468, + 777 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Similarly, given the input $N$ frames of a scene, the uncertainty network is trained with samples containing $M(M < N)$ adjacent frames to fit into limited GPU memory. The loss is a weighted sum of our KL-divergence loss and a BEV segmentation loss (Sec. 4.2). During inference, we apply the uncertainty network to all the $N$ frames independently and use region-centric aggregation to fuse single-frame semantics into a unified HD map.", + "bbox": [ + 75, + 780, + 470, + 902 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 500, + 294, + 633, + 310 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Dataset and Implementation Details", + "text_level": 1, + "bbox": [ + 500, + 315, + 812, + 330 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Dataset. We conduct experiments on a large-scale autonomous driving dataset: nuScenes [3]. It contains 850 videos with 28,130 and 6,019 frames for training and validation, respectively. On each timestamp, six surrounding cameras collect high-resolution images as input.", + "bbox": [ + 496, + 338, + 890, + 415 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Evaluation metrics. Following prior work [13], we compute the intersection-over-union (IoU) for HD map categories: divider, pedestrian crossing, and road boundaries. To highlight the challenge of predicting a scene-scale HD map, our evaluation adopts both a short-range setting [13] covering $60\\mathrm{m} \\times 30\\mathrm{m}$ and a new long-range setting covering $100\\mathrm{m} \\times 100\\mathrm{m}$ , which aligns with the common perception range in self-driving [7, 9]. Without further mentioning, we conduct our ablation studies under the more challenging long-range setting.", + "bbox": [ + 496, + 417, + 892, + 569 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Implementation details. We follow the training and inference settings in Sec. 4.4 and discuss the details in Sec. G (Supplementary). We emphasize that MV-Map is scalable to large volumes of offboard data. Within 15 minutes on a single A40 GPU, our Voxel-NeRF can optimize the 3D structure from each nuScenes sequence, which typically has over 1k images covering regions with an average length of $\\sim 300\\mathrm{m}$ , less than 1 second per frame. In comparison, the common multi-view stereo baseline of COLMAP [34] may take several hours or even days. Notably, this is because COLMAP spent most of the time in feature matching, which is pairwise across frames and $\\mathcal{O}(N^2)$ regarding the frame number $N$ . In comparison, the time complexity of NeRF is $\\mathcal{O}(N)$ . Moreover, our uncertainty network is trained on the samples with $M = 5$ adjacent frames to fit into our GPU memory, but it can jointly handle all the frames ( $\\sim 40$ ) in a nuScenes sequence during the inference stage, as explained in Sec. 4.4.", + "bbox": [ + 496, + 571, + 892, + 844 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.2. Comparison with State-of-the-Art Methods", + "text_level": 1, + "bbox": [ + 500, + 849, + 867, + 866 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "As our work represents the first study on offboard HD map generation, there are no readily available competing", + "bbox": [ + 500, + 869, + 890, + 901 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "8663", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/24eae29a54f63f3a2c8bc4a4aae1e805c07db84ba1161c89adffbe719c61db92.jpg", + "table_caption": [ + "Table 2: MV-Map significantly improves vectorized HD map quality over both the onboard VectorMapNet [18] model and the recent temporal fusion method Neural Map Prior [41] (NMP). $(\\dagger$ means the performance reported in NMP; $\\ddagger$ means the performance from VectorMapNet's officially released checkpoint.)" + ], + "table_footnote": [], + "table_body": "
MethodsmAP
DividerPed CrossingBoundaryAll
VectorMapNet†47.336.139.340.9
+NMP49.642.941.944.8
ΔmAP+2.3+6.8+2.6+3.9
VectorMapNet‡47.739.838.942.1
+MV-Map55.046.245.548.9
Δ mAP+7.3+6.4+6.6+6.7
", + "bbox": [ + 107, + 184, + 434, + 292 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "methods. Additionally, our MV-Map can utilize any off-the-shelf onboard model as its internal component. To ensure a meaningful and fair comparison, we organize the experimental results and analysis in Table 1 as follows.", + "bbox": [ + 75, + 297, + 468, + 358 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "First, our onboard model adopts the simple-yet-effective design from SimpleBEV [11]. As shown in the \" onboard\" rows, our onboard model already consistently outperforms previous baselines in both short-range and long-range settings. Second, our MV-Map brings a significant improvement of $\\sim 7\\%$ mIoU compared with our already effective onboard model. Notably, our offboard method is better than HDMapNet [13] by around $50\\%$ with over $15\\%$ IoU increase on all the categories. Finally, we develop an offboard baseline algorithm called \"Average Fusion.\" It does not consider the quality of different viewpoints and performs region-centric aggregation by equally averaging the single-frame semantic maps. Compared with \"Average fusion,\" our MV-Map still improves the HD map quality by a large margin of over $\\sim 7\\%$ mIoU under the long-range setting.", + "bbox": [ + 75, + 359, + 468, + 585 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.3. Comparison on Vectorized HD Maps", + "text_level": 1, + "bbox": [ + 76, + 590, + 397, + 606 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We further extend our MV-Map to vectorized HD map generation to demonstrate its wide compatibility. In Table 2, we apply MV-Map to VectorMapNet [18], one of the state-of-the-art onboard models generating vectorized HD maps. Specifically, our MV-Map performs uncertainty-aware fusion on the frozen BEV features of an open-sourced VectorMapNet model. The results show that MV-Map improves the HD Map generation quality by a large margin of over $\\sim 7$ mAP, proving its effectiveness in constructing high-quality HD maps. We further compare MV-Map with the recent neural map prior (NMP) [41], which also capitalizes long-term temporal fusion for global HD map generation in Table 2. In the experiments, We adopt the same metric (mAP) as VectorMapNet [18]. As clearly illustrated, our offboard MV-Map pipeline is better in both absolute (48.9 mAP vs. 44.8 mAP) and relative improvements (6.8 mAP vs. 3.9 mAP).", + "bbox": [ + 75, + 609, + 468, + 864 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/aeff25dfcfe46748f80cd6fd3eac9f608a748a46e5ae9bf1a78e430081f1ac9a.jpg", + "table_caption": [ + "Table 3: The components in MV-Map effectively improve HD map generation step by step. We analyze the uncertainty network (UN) and KL-divergence loss $(\\mathcal{L}_{\\mathrm{KL}})$ discussed in Sec. 4.2, and Voxel-NeRF (NeRF) and totalvariance loss $(\\mathcal{L}_{\\mathrm{TV}})$ discussed in Sec. 4.3." + ], + "table_footnote": [], + "table_body": "
IDOffboard ComponentmIoU
UN\\( \\mathcal{L}_{\\text{KL}} \\)NeRF\\( \\mathcal{L}_{\\text{TV}} \\)DividerCrossingBoundaryAll
1Onboard Model39.3026.4439.1034.95
2Average fusion42.8324.7543.9137.16
3✓46.9030.3049.0742.09
4✓✓47.3831.1149.5342.67
5✓✓✓47.6432.3649.6743.22
6✓✓✓48.0132.6550.1243.59
7✓✓✓✓48.1533.3450.2843.92
", + "bbox": [ + 506, + 169, + 888, + 284 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.4. Ablation Studies", + "text_level": 1, + "bbox": [ + 500, + 306, + 663, + 321 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "MV-Map Components. We quantify the improvement from each offboard module in Table 3. (1) Region-centric fusion baseline. Beginning from the onboard model (row 1), we first apply average fusion (row 2) to it (discussed in Sec. 5.2) as a baseline. The improvement indicates that our region-centric design indeed helps by fusing numerous frames into a unified HD map. (2) Uncertainty network. Replacing the average fusion (row 2) with the uncertainty network (row 3) enables larger contributions from more reliable frames and the $\\sim 5\\%$ increase in mIoU validates that assessing quality is critical for better HD map quality. (3) KL-divergence loss. The $\\sim 0.5\\%$ mIoU on using KL-divergence loss or not (row 3 and row 4) supports that explicitly supervising the uncertainty network with KL-divergence effectively improves the region-centric fusion to rely on frames with higher quality. (4) Voxel-NeRF. Adding NeRF to a full-fledged uncertainty network further improves the mIoU (row 4 and row 5). In the category-level analysis, we highlight that NeRF is critical for the fusion especially on the challenging structures with smaller regions, e.g., pedestrian crossings. This evidence validates the importance of global geometry in multi-view consistency. (5) Total-variance loss. Utilizing it further boosts the performance in all the scenarios, validating our effort to dedicate NeRFs for the downstream HD map generation.", + "bbox": [ + 496, + 335, + 890, + 714 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Scaling to more frames. We demonstrate that our fusion strategy can handle and significantly benefit from a larger number of frames, which is critical for offboard HD map generation. We evaluate our offboard framework under varied input frames in Fig. 5. MV-Map can utilize all the keyframes (40 frames) in nuScenes and this number is only bounded by the sequence length. As clearly shown in the blue curve of Fig. 5, MV-Map benefits from more frames, indicating its scalability for offboard scenarios, especially compared with the average fusion baseline, whose performance drops after using more than 15 frames. This indicates that our region-centric fusion strategy is able to", + "bbox": [ + 496, + 719, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_footnote", + "text": "$^{1}$ NMP is not included for semantic HD map comparison in Sec. 5.2 because it adopts a different resolution for rasterized HD maps.", + "bbox": [ + 75, + 875, + 468, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "8664", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/f8ccfd58057f755d85868db82752e779100ba64f07cbe7c9d987cc9512a8beee.jpg", + "image_caption": [ + "Figure 5: Our MV-Map can significantly benefit from more input frames, which is attractive for offboard applications. Notably, the performance of the \"average fusion\" baseline saturates and even decreases with more input frames." + ], + "image_footnote": [], + "bbox": [ + 107, + 90, + 441, + 265 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/c4885b7a41cc4c5b87b1b581e9334bd2b9af6ec538b2cc2bd412a16176c6b361.jpg", + "image_caption": [ + "Figure 6: Qualitative comparison in the long-range settings. HD map generated offboard has significantly better quality by fixing the artifacts of the onboard model." + ], + "image_footnote": [], + "bbox": [ + 83, + 327, + 464, + 555 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "reason the complementary regions among the frames, instead of blindly averaging them all.", + "bbox": [ + 75, + 633, + 468, + 664 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Qualitative comparison. We visualize the generated HD maps in Fig. 6. As clearly shown, MV-Map corrects the artifacts from onboard models and achieves better completeness and details. In addition, the HD maps generated offboard have high fidelity compared with the ground truth, especially in the center regions covered by more frames.", + "bbox": [ + 75, + 667, + 468, + 758 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Analyzing KL-divergence and confidence scores. We empirically analyze the output of the uncertainty network in Fig. 7. As for the confidence scores, we observe that they indeed decrease the contributions of unreliable regions, such as the part with occlusion in Fig. 7a, highlighted with solid circles. The invisible area has much smaller confidence than its nearby regions. Additionally, we transfer the KL-divergence prediction head to the validation set and find the predictions reasonably correlate with the confidence scores,", + "bbox": [ + 75, + 763, + 470, + 901 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/cb82f8c971dc62d190b3c944ba60267ae396f7b132aa1fd0aeb6aa10d9e4acfe.jpg", + "image_caption": [ + "Figure 7: (a) The confidence scores predicted by the uncertainty network capture the challenging regions (solid circles) as the occluded region has significantly smaller confidence values than its nearby regions. Darker colors indicate smaller confidence values. (b) Predicted KL divergence between the prediction and ground truth label captures the connection with the predicted confidence scores (dashed circles). The region with a dashed circle has a much larger predicted KL-divergence value than its nearby regions. Accordingly, this area exhibits smaller confidence scores. Darker colors mean smaller KL-divergence values." + ], + "image_footnote": [], + "bbox": [ + 506, + 90, + 888, + 284 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "as in Fig. 7b. We notice that the regions with higher KL-divergence values (Fig. 7b) also have lower confidences (Fig. 7a), highlighted with the dashed circles.", + "bbox": [ + 496, + 479, + 890, + 525 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Using geometric information from data-driven priors. Our Voxel-NeRF offers geometric information in a fully self-supervised manner. Meanwhile, our MV-Map framework is general and can leverage alternative approaches for providing geometric information, such as learning data-driven priors from large-scale datasets. We investigate this type of approach here and consider representative monocular depth estimators that are learned off-the-shelf in a supervised manner. Specifically, we replace the rendering process of Voxel-NeRF with the results from NeWCRFs [45] (details in Sec. G, Supplementary). As in Table 4, monocular depth can improve the uncertainty fusion as well (row 2 and row 3). We further notice that NeRF performs slightly better because it encodes multiple views consistently in a shared 3D structure, while monocular depth considers each view independently and suffers from scale variation across frames. Encouraged by the benefits of these two distinct types of geometric information, future work is to combine NeRF with learnable priors into our framework.", + "bbox": [ + 496, + 530, + 890, + 816 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.5. Globally Consistent HD Map Generation", + "text_level": 1, + "bbox": [ + 498, + 830, + 851, + 847 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Our offboard MV-Map can handle numerous frames. Its application is to expand the range of HD map generation from a local region around the ego-vehicle to a global re", + "bbox": [ + 498, + 854, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "8665", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/55429bb0e6b5838c37e918a69ecaf9b7f40fe7327e076b975cb4ce9c85958b86.jpg", + "image_caption": [ + "Figure 8: Visualization of a unified, scene-scale HD map through our MV-Map. It can fuse numerous frames and generate global-scale HD maps with high quality. It is also robust under different weather conditions and complex road topology." + ], + "image_footnote": [], + "bbox": [ + 163, + 89, + 803, + 265 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/c1496fa20e64101c0d3615fd6888ee060962fa684c81caca2fcaa7bf32fdaec0.jpg", + "table_caption": [ + "Table 4: MV-Map is a general framework: In addition to NeRF, MV-Map can benefit from data-driven priors of geometric information; here we use monocular depth estimation [45] as an example. \"UN-Only:\" using the uncertainty network without augmentation of 3D structural information. Then we separately incorporate mono-depth or NeRF to it." + ], + "table_footnote": [], + "table_body": "
MethodsmIoU
DividerPed CrossingBoundaryAll
Average Fusion42.8324.7543.9137.16
MV-Map (UN-Only)47.3831.1149.5342.67
MV-Map (Mono-Depth)48.0432.9650.0843.69
MV-Map (NeRF)48.1533.3450.2843.92
", + "bbox": [ + 80, + 415, + 465, + 503 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/addba26e036399e1a23647aba3d4ac1b5e4ab4b52f2034aeeb3bd6a3476736ed.jpg", + "table_caption": [ + "Table 5: Performance of incorporating the LiDAR modality in MV-Map, evaluated under the long-range setting on the validation set. As a general framework, MV-Map can exploit multi-modality as input and improve the performance consistently and significantly." + ], + "table_footnote": [], + "table_body": "
MethodsmIoU (Long-range)
DividerPed CrossingBoundaryAll
Onboard41.6327.1341.6536.80
MV-Map50.7232.9954.6346.11
", + "bbox": [ + 83, + 594, + 460, + 667 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "gion covering all the input frames, which saves the labor in stitching multiple local predictions in the real world. Our global maps in Fig. 8 demonstrate high fidelity for complex topology in two challenging scenes. While some regions do not match the ground truth, we argue that these regions fall outside the collected frames and perception ranges, which are beyond the scope of offboard algorithms.", + "bbox": [ + 75, + 680, + 468, + 787 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5.6. Generalizability of MV-Map with LiDAR", + "text_level": 1, + "bbox": [ + 76, + 800, + 429, + 816 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "To demonstrate the generalizability of our framework, we analyze incorporating the LiDAR sensor into MV-Map. In the main paper, we focused on cameras, because they contribute primarily to HD map generation as shown in HDMapNet [13]. On the other hand, LiDARs are also", + "bbox": [ + 75, + 824, + 468, + 902 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "widely used for their accurate distance sensing and their ability to enhance localization, which motivates our investigation here. We first describe the design of utilizing the extra LiDAR modality and then analyze the results. Extra details are explained in Sec. C (Supplementary).", + "bbox": [ + 496, + 321, + 892, + 398 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 404, + 617, + 419 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Regarding the infrastructure role of HD maps, we propose a novel offboard HD map generation setup to address the unreliability of onboard BEV perception. By removing the computation constraints, the models are allowed to reason all the frames altogether and construct multi-view consistent HD maps. Concretely, we propose an offboard HD map generation framework called MV-Map. To address numerous frames, MV-Map designs region-centric aggregation to unify the HD maps from all the frames. The key design is an uncertainty network that weighs the contribution of different frames and utilizes a Voxel-NeRF to provide multi-view consistent 3D structural information. Experiments validate that MV-Map is scalable to large volumes of offboard data and significantly improves the HD map quality. We hope that our framework can become an effective augmentor for onboard algorithms and also inspire future research on offboard problems.", + "bbox": [ + 496, + 422, + 892, + 679 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Limitations and future work. Although our Voxel-NeRF improves the offboard pipeline in a scalable way, several challenges still present, including moving objects in traffic scenes and exploiting data-driven priors for better geometric information. In addition, we seek to connect our work with auto-labeling and compare it with human annotation quality, so as to explore more potential applications such as autonomous vehicle navigation and urban planning.", + "bbox": [ + 496, + 681, + 892, + 803 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement. This work was supported in part by NSF Grant 2106825, NIFA Award 2020-67021-32799, the Jump ARCHES endowment, the NCSA Fellows program, the Illinois-Inspers Partnership, and the Amazon Research Award. This work used NVIDIA GPUs at NCSA Delta through allocations CIS220014 and CIS230012 from the ACCESS program.", + "bbox": [ + 496, + 803, + 893, + 901 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "8666", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Mohamed Aly. Real time detection of lane markers in urban streets. In IEEE Intelligent Vehicles Symposium, 2008. 3", + "[2] Massimo Bertozzi and Alberto Broggi. Real-time lane and obstacle detection on the GOLD system. In IEEE Intelligent Vehicles Symposium, 1996. 3", + "[3] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuScenes: A multimodal dataset for autonomous driving. In CVPR, 2020. 1, 2, 3, 5, 6", + "[4] Ming-Fang Chang, John W Lambert, Patsorn Sangkloy, Jagjeet Singh, Slawomir Bak, Andrew Hartnett, De Wang, Peter Carr, Simon Lucey, Deva Ramanan, and James Hays. Argo-verse: 3D tracking and forecasting with rich maps. In CVPR, 2019. 1", + "[5] Kangle Deng, Andrew Liu, Jun-Yan Zhu, and Deva Ramanan. Depth-supervised NeRF: Fewer views and faster training for free. In CVPR, 2022. 3", + "[6] Liuuyuan Deng, Ming Yang, Hao Li, Tianyi Li, Bing Hu, and Chunxiang Wang. Restricted deformable convolution-based road scene semantic segmentation using surround view cameras. In ITSC, 2020. 3", + "[7] Hao Dong, Xianjing Zhang, Xuan Jiang, Jun Zhang, Jintao Xu, Rui Ai, Weihao Gu, Huimin Lu, Juho Kannala, and Xieyuanli Chen. SuperFusion: Multilevel LiDAR-camera fusion for long-range HD map generation and prediction. arXiv preprint arXiv:2211.15656, 2022. 6", + "[8] Scott Ettinger, Shuyang Cheng, Benjamin Caine, Chenxi Liu, Hang Zhao, Sabeek Pradhan, Yuning Chai, Ben Sapp, Charles R. Qi, Yin Zhou, Zoey Yang, Aur'elien Chouard, Pei Sun, Jiquan Ngiam, Vijay Vasudevan, Alexander McCauley, Jonathon Shlens, and Dragomir Anguelov. Large scale interactive motion forecasting for autonomous driving: The Waymo open motion dataset. In ICCV, 2021. 1", + "[9] Lue Fan, Yuxue Yang, Feng Wang, Naiyan Wang, and Zhaoxiang Zhang. Super sparse 3D object detection. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2023. 6", + "[10] Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, 2022. 3", + "[11] Adam W Harley, Zhaoyuan Fang, Jie Li, Rares Ambrus, and Katerina Fragkiadaki. Simple-BEV: What really matters for multi-sensor BEV perception? In ICRA, 2023. 1, 3, 4, 7", + "[12] Anthony Hu, Zak Murez, Nikhil Mohan, Sofia Dudas, Jeffrey Hawke, Vijay Badrinarayanan, Roberto Cipolla, and Alex Kendall. FIERY: Future instance prediction in Bird's-Eye View from surround monocular cameras. In ICCV, 2021. 3", + "[13] Qi Li, Yue Wang, Yilun Wang, and Hang Zhao. HDMapNet: An online hd map construction and evaluation framework. In ICRA, 2022. 1, 3, 5, 6, 7, 9", + "[14] Yinhao Li, Zheng Ge, Guanyi Yu, Jinrong Yang, Zengran Wang, Yukang Shi, Jianjian Sun, and Zeming Li. BEVDepth: Acquisition of reliable depth for multi-view 3D object detection. In AAAI, 2023. 3" + ], + "bbox": [ + 78, + 114, + 468, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[15] Zhiqi Li, Wenhai Wang, Hongyang Li, Enze Xie, Chonghao Sima, Tong Lu, Yu Qiao, and Jifeng Dai. BEVFormer: Learning Bird's-Eye-View representation from multi-camera images via spatiotemporal transformers. In ECCV, 2022. 1, 3", + "[16] Benchcheng Liao, Shaoyu Chen, Xinggang Wang, Tianheng Cheng, Qian Zhang, Wenyu Liu, and Chang Huang. MapTR: Structured modeling and learning for online vectorized HD map construction. In ICLR, 2023. 3", + "[17] Lingjie Liu, Jiatao Gu, Kyaw Zaw Lin, Tat-Seng Chua, and Christian Theobalt. Neural sparse voxel fields. In NeurIPS, 2020. 3", + "[18] Yicheng Liu, Yuan Yuantian, Yue Wang, Yilun Wang, and Hang Zhao. VectorMapNet: End-to-end vectorized HD map learning. In ICML, 2023. 3, 7", + "[19] Zhijian Liu, Haotian Tang, Alexander Amini, Xingyu Yang, Huizi Mao, Daniela Rus, and Song Han. BEVFusion: Multi-task multi-sensor fusion with unified Bird's-Eye View representation. In ICRA, 2023. 3", + "[20] Ricardo Martin-Brualla, Noha Radwan, Mehdi S. M. Sajjadi, Jonathan T. Barron, Alexey Dosovitskiy, and Daniel Duckworth. NeRF in the wild: Neural radiance fields for unconstrained photo collections. In CVPR, 2021. 3", + "[21] Tim Meinhardt, Alexander Kirillov, Laura Leal-Taixe, and Christoph Feichtenhofer. TrackFormer: Multi-object tracking with transformers. In CVPR, 2022. 6", + "[22] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan Barron, Ravi Ramamoorthi, and Ren Ng. NeRF: Representing scenes as neural radiance fields for view synthesis. In ECCV, 2020. 2, 3, 5", + "[23] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Trans. Graph., 2022. 3", + "[24] Mahyar Najibi, Jingwei Ji, Yin Zhou, Charles R Qi, Xinchen Yan, Scott Ettinger, and Dragomir Anguelov. Motion inspired unsupervised perception and prediction in autonomous driving. In ECCV, 2022. 2", + "[25] Thomas Neff, Pascal Stadlbauer, Mathias Parger, Andreas Kurz, Joerg H. Mueller, Chakravarty R. Alla Chaitanya, Anton S. Kaplanyan, and Markus Steinberger. DONeRF: Towards real-time rendering of compact neural radiance fields using depth oracle networks. In Computer Graphics Forum, 2021. 3", + "[26] Mong H. Ng, Kaahan Radia, Jianfei Chen, Dequan Wang, Ionel Gog, and Joseph E Gonzalez. BEV-Seg: Bird's Eye View semantic segmentation using geometry and semantic point cloud. arXiv preprint arXiv:2006.11436, 2020. 3", + "[27] Bowen Pan, Jiankai Sun, Ho Yin Tiga Leung, Alex Andonian, and Bolei Zhou. Cross-view semantic segmentation for sensing surroundings. IEEE Robotics and Automation Letters, 2020. 3", + "[28] Ziqi Pang, Zhichao Li, and Naiyan Wang. Model-free vehicle tracking and state estimation in point cloud sequences. In IROS, 2021. 2", + "[29] Jonah Philion and Sanja Fidler. Lift, Splat, Shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3D. In ECCV, 2020. 3, 6" + ], + "bbox": [ + 501, + 92, + 890, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "8667", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[30] Charles R Qi, Yin Zhou, Mahyar Najibi, Pei Sun, Khoa Vo, Boyang Deng, and Dragomir Anguelov. Offboard 3D object detection from point cloud sequences. In CVPR, 2021. 2, 3", + "[31] Lennart Reiher, Bastian Lampe, and Lutz Eckstein. A Sim2Real deep learning approach for the transformation of images from multiple vehicle-mounted cameras to a semantically segmented image in Bird's Eye View. In ITSC, 2020. 3", + "[32] Konstantinos Rematas, Andrew Liu, Pratul P. Srinivasan, Jonathan T. Barron, Andrea Tagliasacchi, Tom Funkhouser, and Vittorio Ferrari. Urban radiance fields. In CVPR, 2022. 3", + "[33] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In Medical Image Computing and Computer-Assisted Intervention (MICCAI), 2015. 4", + "[34] Johannes Lutz Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In CVPR, 2016. 2, 6", + "[35] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In CVPR, 2022. 3", + "[36] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Improved direct voxel grid optimization for radiance fields reconstruction. arXiv preprint arXiv:2206.05085, 2022. 3, 5", + "[37] Matthew Tancik, Vincent Casser, Xinchen Yan, Sabeek Pradhan, Ben Mildenhall, Pratul Srinivasan, Jonathan T. Barron, and Henrik Kretzschmar. Block-NeRF: Scalable large scene neural view synthesis. In CVPR, 2022. 3", + "[38] Yi Wei, Shaohui Liu, Yongming Rao, Wang Zhao, Jiwen Lu, and Jie Zhou. NerfingMVS: Guided optimization of neural radiance fields for indoor multi-view stereo. In ICCV, 2021. 3", + "[39] Benjamin Wilson, William Qi, Tanmay Agarwal, John Lambert, Jagjeet Singh, Siddhesh Khandelwal, Bowen Pan, Ratnesh Kumar, Andrew Hartnett, Jhony Kaesemodel Pontes, Deva Ramanan, Peter Carr, and James Hays. Argoverse 2: Next generation datasets for self-driving perception and forecasting. In Proceedings of the Neural Information Processing Systems Track on Datasets and Benchmarks (NeurIPS Datasets and Benchmarks 2021, 2023. 1", + "[40] Ziyang Xie, Junge Zhang, Wenye Li, Feihu Zhang, and Li Zhang. S-NeRF: Neural radiance fields for street views. In ICLR, 2023. 3", + "[41] Xuan Xiong, Yicheng Liu, Tianyuan Yuan, Yue Wang, Yilun Wang, and Hang Zhao. Neural map prior for autonomous driving. In CVPR, 2023. 3, 7", + "[42] Qiangeng Xu, Zexiang Xu, Julien Philip, Sai Bi, Zhixin Shu, Kalyan Sunkavalli, and Ulrich Neumann. Point-NeRF: Point-based neural radiance fields. In CVPR, 2022. 3", + "[43] Bin Yang, Min Bai, Ming Liang, Wenyuan Zeng, and Raquel Urtasun. Auto4D: Learning to label 4D objects from sequential point clouds. arXiv preprint arXiv:2101.06586, 2021. 2", + "[44] Yao Yao, Zixin Luo, Shiwei Li, Tian Fang, and Long Quan. MVSNet: Depth inference for unstructured multiview stereo. In ECCV, 2018. 2", + "[45] Weihao Yuan, Xiaodong Gu, Zuozhuo Dai, Siyu Zhu, and Ping Tan. NeWCRFs: Neural window fully-connected CRFs for monocular depth estimation. In CVPR, 2022. 8, 9" + ], + "bbox": [ + 78, + 90, + 470, + 900 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[46] Fangao Zeng, Bin Dong, Yuang Zhang, Tiancai Wang, Xi-angyu Zhang, and Yichen Wei. MOTR: End-to-end multiple-object tracking with transformer. In ECCV, 2022. 6", + "[47] Xi Zhu, Xiya Cao, Zhiwei Dong, Caifa Zhou, Qiangbo Liu, Wei Li, and Yongliang Wang. Nemo: Neural map growing system for spatiotemporal fusion in bird's-eye-view and bdd-map benchmark. arXiv preprint arXiv:2306.04540, 2023. 3" + ], + "bbox": [ + 501, + 90, + 890, + 191 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "8668", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/59188c7c-19e6-4a92-b752-2ffcc7690379_model.json b/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/59188c7c-19e6-4a92-b752-2ffcc7690379_model.json new file mode 100644 index 0000000000000000000000000000000000000000..e8fb63b59c0239c0ca2505af998a4bff9f82baf7 --- /dev/null +++ b/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/59188c7c-19e6-4a92-b752-2ffcc7690379_model.json @@ -0,0 +1,2081 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.13, + 0.131, + 0.84, + 0.154 + ], + "angle": 0, + "content": "MV-Map: Offboard HD Map Generation with Multi-view Consistency" + }, + { + "type": "text", + "bbox": [ + 0.224, + 0.18, + 0.748, + 0.234 + ], + "angle": 0, + "content": "Ziyang Xie\\*1,2 Ziqi Pang\\*1 Yu-Xiong Wang\\(^{1}\\) \n\\(^{1}\\)University of Illinois Urbana-Champaign \\(^{2}\\)Fudan University \n{ziyang8, ziqip2, yxw}@illinois.edu" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.269, + 0.314, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.302, + 0.474, + 0.71 + ], + "angle": 0, + "content": "While bird's-eye-view (BEV) perception models can be helpful in building high-definition maps (HD maps) with less human labor, their results are often unreliable and demonstrate noticeable inconsistencies in the predicted HD maps from different viewpoints. This is because BEV perception is typically set up in an \"onboard\" manner, which restricts the computation and prevents algorithms from simultaneously reasoning multiple views. This paper overcomes these limitations and advocates a more practical \"offboard\" HD map generation setup that removes the computation constraints, based on the fact that HD maps are commonly reusable infrastructures built offline in data centers. To this end, we propose a novel offboard pipeline called MV-Map that capitalizes multi-view consistency and can handle an arbitrary number of frames with the key design of a \"region-centric\" framework. In MV-Map, the target HD maps are created by aggregating all the frames of onboard predictions, weighted by the confidence scores assigned by an \"uncertainty network.\" To further enhance multi-view consistency, we augment the uncertainty network with the global 3D structure optimized by a voxelized neural radiance field (Voxel-NeRF). Extensive experiments on nuScenes show that our MV-Map significantly improves the quality of HD maps, further highlighting the importance of offboard methods for HD map generation. Our code and model are available at https://github.com/ZiYang-xie/MV-Map." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.742, + 0.21, + 0.757 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.768, + 0.47, + 0.875 + ], + "angle": 0, + "content": "High-definition maps (HD maps) play a crucial role in ensuring the safe navigation of autonomous vehicles, by providing essential positional and semantic information about road elements. Ideally, one would expect the process of constructing HD maps to be as simple as collecting numerous sensory data while driving and then utilizing an automatic algorithm to extract the road elements," + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.269, + 0.889, + 0.446 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.455, + 0.893, + 0.561 + ], + "angle": 0, + "content": "Figure 1: Current onboard methods generate unreliable HD map predictions that are inconsistent across multiple views, due to occlusions or viewpoint changes. By contrast, our offboard pipeline constructs a unified and multi-view consistent HD map with clearer lanes. Our key design is a region-centric framework that aggregates single-frame information for each target HD map region." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.58, + 0.893, + 0.746 + ], + "angle": 0, + "content": "as illustrated in Fig. 1. However, the mainstream solutions generally involve human annotators, as seen in widely-used datasets [3, 4, 8, 39]. This design is based on the consideration of the infrastructure role and high re-usability of HD maps, which can serve autonomous vehicles for virtually infinite times after a single construction process before any environmental changes. Even so, the expense of manual annotation obstructs the expansion of autonomous driving to new locations, and we aim to develop reliable algorithms that can decrease or replace the need for human labor in HD map construction." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Towards this goal, there have been recent attempts that automatically generate HD maps using bird's-eye-view (BEV) perception [11, 13, 15]. However, their results are often unreliable, as illustrated by noticeable inconsistencies in the predicted HD maps from different viewpoints (a representative example is in Fig. 1). We argue that multi-view consistency is an intrinsic property of HD maps, because the rigid and static HD maps shouldn't change significantly after simply switching viewpoints. The violations of consistency arise from the fact that existing BEV perception" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.206, + 0.9 + ], + "angle": 0, + "content": "* Equal contribution." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8658" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.088, + 0.09, + 0.468, + 0.187 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.201, + 0.47, + 0.248 + ], + "angle": 0, + "content": "Figure 2: Our Voxel-NeRF reconstructs high-quality 3D structure of the scene. As in the rendering result, the lanes and pedestrian crossings (highlighted) are clear." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.263, + 0.468, + 0.354 + ], + "angle": 0, + "content": "algorithms do not account for all the views explicitly and thus do not align their predictions. This issue further boils down to their onboard setting, where the models are only allowed to access computing devices onboard in autonomous vehicles and can only handle a single frame or a few neighboring frames." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.356, + 0.468, + 0.566 + ], + "angle": 0, + "content": "Given such limitations of the onboard setup, we underline a critical yet under-explored offboard setup that removes the computation constraints. Our offboard setting aligns well with the infrastructure role of HD maps: constructing HD maps can and should utilize powerful data centers to maximize the fidelity of predictions, thus ensuring the safety and reliability of the virtually infinite usages of HD maps. By aggregating information from diverse viewpoints and enhancing consistency, our offboard generation provides a natural improvement. As shown in Fig. 1, having multiple views of a shared region offers richer geometric and semantic cues, as well as improves the completeness of scene understanding, particularly regarding frequent occlusions in urban traffic." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.569, + 0.47, + 0.902 + ], + "angle": 0, + "content": "With HD map construction primarily relying on vision information to infer the semantics, which is different from the previous offboard studies depending on point clouds, we are the first to explore a vision-oriented offboard perception framework to our best knowledge. To this end, we propose Multi-view Map (MV-Map) that leverages information from every frame's viewpoint and generates a unified HD map consistent with all of them. In contrast to the frame-centric design in current onboard methods that merges a fixed number of frames on the input level, we propose a region-centric design inspired by \"offboard 3D detection\" [30] to fully utilize the data from diverse views. Notably, our design can connect every HD map region with an arbitrary number of input frames covering its area. The pipeline of our framework involves extracting all the HD map patches predicted by an off-the-shelf onboard model related to that HD map region, and then fusing the patches into a final result that agrees with all the views, as illustrated in the arrows in Fig. 1. To give more weight to reliable frames, such as those with a clear view of the target region, we introduce an \"uncertainty network\" as a key component, which assigns confidence scores to onboard results and performs a weighted" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.856, + 0.107 + ], + "angle": 0, + "content": "average of HD map patches guided by the confidence." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.109, + 0.892, + 0.456 + ], + "angle": 0, + "content": "We further enhance the consensus among all the frames by augmenting the uncertainty network with cross-view consistency information. Our key insight is to learn a coherent 3D structure from diverse views and provide it as an auxiliary input to the uncertainty network. For this purpose, we exploit neural radiance fields (NeRFs) [22], a state-of-the-art approach that represents 3D structures of scenes. As shown in Fig. 2, our NeRF model synthesizes a high-quality scene structure. Compared with alternative 3D reconstruction strategies like structure from motion (e.g., COLMAP [34]), NeRF is more preferred from a practical perspective, because its runtime grows linearly with the frame number, whereas COLMAP increases quadratically. Moreover, NeRF is fully self-supervised and does not require additional annotations, unlike multi-view stereo methods such as MVSNet [44]. To improve the scalability of NeRF, we leverage a voxelized variant of NeRF (VoxelNeRF) to promote efficiency and propose loss functions that implicitly guide the concentration of NeRF on the near-ground geometry related to HD map generation. Additionally, we highlight NeRF's flexibility and scalability to an arbitrary number of views, making it critical in offboard HD map generation." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.457, + 0.868, + 0.472 + ], + "angle": 0, + "content": "To summarize, we make the following contributions:" + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.474, + 0.891, + 0.518 + ], + "angle": 0, + "content": "1. We are the first to study the problem of learning to generate HD maps offboard, and we are also the first vision-oriented offboard study to our best knowledge." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.519, + 0.891, + 0.564 + ], + "angle": 0, + "content": "2. We propose an effective region-centric framework MV-Map that can generate a multi-view consistent HD map from an arbitrarily large number of frames." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.564, + 0.891, + 0.61 + ], + "angle": 0, + "content": "3. We introduce and extend Voxel-NeRF to encode the 3D structure from all frames for HD map generation tasks, further guiding the fusion for multi-view consistency." + }, + { + "type": "list", + "bbox": [ + 0.5, + 0.474, + 0.891, + 0.61 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.611, + 0.892, + 0.672 + ], + "angle": 0, + "content": "Large-scale experiments on nuScenes [3] show that MV-Map significantly improves HD map quality. Notably, MV-Map can effectively utilize an increasing number of input frames, making it attractive for real-world applications." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.689, + 0.641, + 0.705 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Offboard 3D perception. The need for large-volume training data encourages developing offboard algorithms. Existing studies mainly focus on predicting 3D bounding boxes [24, 28, 30, 43]. The most representative work on \"offboard 3D detection\" [30] extracts multi-frame point clouds in object tracks and refines the 3D bounding boxes with the \"4D\" data. Its success heavily relies on the absolute 3D positions of point clouds, where simply overlaying Li-DAR points can construct denser surfaces of objects. However, in HD map generation that relies on images, it is not straightforward to accumulate imagery data in the 3D space. To overcome this limitation, we propose region-centric fu" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8659" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.138 + ], + "angle": 0, + "content": "sion to aggregate multi-frame information and utilize multiview reconstruction, e.g. NeRF, to encode global geometry. Our study is also the first vision-oriented offboard pipeline." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.141, + 0.473, + 0.474 + ], + "angle": 0, + "content": "BEV segmentation and HD map construction. Onboard HD map construction is closely related to BEV segmentation, as in HDMapNet [13]. The major challenge in BEV segmentation is to map the image features to the 3D world. The conventional approach leverages inverse perspective warping [1, 2, 6, 27, 31]. BEV perception methods either apply attention to capture the transformation [15, 19], incorporate depth information [12, 14, 26, 29], or directly query the features from voxels [11]. To better support downstream applications, some recent methods [16, 18] have developed special decoders to generate vectorized HD maps. Unlike these onboard methods, our proposition is a general offboard pipeline that utilizes any off-the-shelf segmentation models as an internal component and refines its results with multi-view consistent fusion. In this sense, neural map prior [41] and NeMO [47] also propose to perform long-term temporal fusion, but they primarily focus on an onboard setting and cannot fully leverage the multi-view consistency from long video sequences. Compared with them, our MV-Map is an offboard framework and explicitly accounts for the geometry of diverse views by reconstructing the 3D structure of the scene." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.478, + 0.473, + 0.766 + ], + "angle": 0, + "content": "Neural radiance fields. NeRF [22] has shown outstanding capability in 3D reconstruction. Recent work [20, 32, 37, 40] has extended NeRF into large unbounded scenes, such as city-scale NeRF with ego-centric camera settings [32, 37, 40] and improvement from depth-supervised methods [5, 25, 38, 42]. With NeRF's ability to optimize 3D structures from numerous views, it becomes an ideal method to enforce multi-view consistency for offboard perception. However, as we are the first to adapt NeRF for HD map generation, some important modifications are made. First, we adopt voxel-based NeRF [10, 17, 23, 35, 36] to accelerate the NeRF training by voxelizing the space and encoding the parameters for each position in the voxels. This allows us to reconstruct a huge scene from nuScenes within minutes. In addition, we propose a \"total-variance loss\" to enhance NeRF's concentration on the near-ground geometry, which also reflects the shift of concentration from pixel quality to downstream HD map generation." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.78, + 0.36, + 0.798 + ], + "angle": 0, + "content": "3. Offboard HD Map Generation" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.807, + 0.47, + 0.868 + ], + "angle": 0, + "content": "Given a sequence of sensory data, the goal of HD map generation is to predict the positions and semantics of road elements in the BEV space, including road dividers, road boundaries, and pedestrian crossings." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Problem statement. We consider the input of HD map generation as \\(\\mathcal{D} = \\{(I_i, P_i)\\}_{i=1}^N\\), where \\(I_i\\) denotes the \\(i\\)-th" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.29 + ], + "angle": 0, + "content": "sensor frame, \\( P_{i} \\) is the set of associated sensor poses, and \\( N \\) is the total number of frames in the database representing diverse views of a scene captured by a moving ego vehicle. The output is denoted as \\( \\mathcal{M} = \\{M_i\\}_{i=1}^N \\), where \\( M_{i} \\) is the HD map for the region nearby the ego vehicle on frame \\( i \\). Following HDMapNet [13], we define \\( M_{i} \\) as a local semantic map on BEV. Note that the aforementioned formulation is agnostic to sensor types. In the main paper, we mainly focus on vision-oriented HD map generation, and we extend it to leveraging additional LiDAR data in Sec. 5.6. Specifically, every frame \\( I_{i} \\) contains \\( K = 6 \\) RGB images \\( \\{I_{i,j}\\}_{j=1}^{K} \\) on nuScenes [3], and \\( P_{i} = \\{P_{i,j}\\}_{j=1}^{K} \\) comprises of the intrinsic and extrinsic matrices of corresponding cameras." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.294, + 0.893, + 0.431 + ], + "angle": 0, + "content": "Offboard vs. onboard settings. Compared with the conventional onboard setup, our offboard setup offers greater flexibility in terms of speed and computation resources. Onboard HD map generation algorithms are often constrained by efficiency requirements and cannot use all the \\(N\\) frames in a single run. By contrast, offboard algorithms are allowed to have access to all the \\(N\\) frames, and can then leverage the offline setting and abundant computation resources to generate HD maps of higher quality." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.434, + 0.893, + 0.646 + ], + "angle": 0, + "content": "From frame-centric to region-centric designs. There are different strategies to utilize the temporal data from \\(N\\) frames, similar to offboard 3D detection [30]. A direct solution is frame-centric [30], in which we naively increase the number of frames for existing onboard HD map construction methods, typically BEV segmentation models, and extend them to long sequences. While previous work [13, 15] has illustrated the benefit of longer temporal horizons, a multi-frame BEV segmentation model can only handle a fixed number of input frames, and increasing the frame number requires a linear growth in GPU capacity. Therefore, simply scaling up the input frames of existing onboard models is not an effective way of exploiting the offboard data, which often have varying and large frame numbers." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.646, + 0.892, + 0.752 + ], + "angle": 0, + "content": "To overcome the limitations of the frame-centric design, we propose a novel region-centric design that adaptively aggregates information from an arbitrary number of available frames for each HD map region. Our design is inspired by the object-centric notion in 3D detection [30], but extends to the task of HD map construction. Doing so enables the consensus across frames captured from different viewpoints." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.766, + 0.74, + 0.785 + ], + "angle": 0, + "content": "4. Method: Multi-view Map" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.893, + 0.903 + ], + "angle": 0, + "content": "Overview. Fig. 3 illustrates the overall framework of our Multi-view Map (MV-Map). An onboard HD map model processes every frame \\((I_i, P_i)\\) and generates its corresponding BEV feature map \\(F_i\\) and HD map semantics \\(S_i\\) (Sec. 4.1). Then, an uncertainty network assesses the reliability of the single-frame information \\(F_i\\) for every region on the HD map (Sec. 4.2). Meanwhile, a voxelized NeRF" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.517, + 0.957 + ], + "angle": 0, + "content": "8660" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.145, + 0.089, + 0.825, + 0.271 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.075, + 0.277, + 0.895, + 0.34 + ], + "angle": 0, + "content": "Figure 3: Offboard pipeline of MV-Map. Given an arbitrary number of input frames, MV-Map first leverages an off-the-shelf onboard model to generate BEV features and semantic maps for each frame. Then an uncertainty network predicts their corresponding confidence maps and guides the region-centric aggregation of a unified HD map. Our pipeline further develops a Voxel-NeRF tailored to 3D structures related to HD maps to augment MV-Map with multi-view geometry." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.354, + 0.473, + 0.446 + ], + "angle": 0, + "content": "\\(f_{\\mathrm{NeRF}}\\) optimizes a global 3D structure from all \\(N\\) frames and provides multi-view consistency information to the uncertainty network (Sec. 4.3). The final prediction for every region on the HD map is produced by a weighted average of the single-frame semantics \\(S_{i}\\), which enables handling an arbitrary number of frames." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.456, + 0.24, + 0.47 + ], + "angle": 0, + "content": "4.1. Onboard Model" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.479, + 0.47, + 0.57 + ], + "angle": 0, + "content": "The onboard model is the entry point of our pipeline. Most existing HD map generation methods follow an encoder-decoder design. The encoder generates a BEV feature map \\( F_{i} \\) from the input \\( (I_i, P_i) \\) as \\( \\mathsf{Encoder}(I_i, P_i) \\to F_i \\), and the decoder converts the feature map \\( F_{i} \\) into a semantic map \\( S_{i} \\) as \\( \\mathsf{Decoder}(F_i) \\to S_i \\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.571, + 0.471, + 0.662 + ], + "angle": 0, + "content": "Since our pipeline only requires the BEV feature map \\( F_{i} \\) to activate the subsequent modules, MV-Map is agnostic to specific encoder-decoder designs. Without the loss of generality, we mainly adopt the encoder in SimpleBEV [11] and use a lightweight convolutional decoder. Results based on additional models are in Table D (Supplementary)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.665, + 0.471, + 0.817 + ], + "angle": 0, + "content": "Encoder. For each frame, a convolutional backbone first converts \\(K\\) images \\(\\{I_{i,j}\\}_{j = 1}^{K}\\) into 2D image feature maps \\(\\{F_{i,j}^{2\\mathrm{D}}\\}_{j = 1}^{K}\\). The features are then lifted into the 3D world, through a set of voxels that are pre-defined by the encoder with shape \\(X\\times Y\\times Z\\) centered around the ego vehicle: the 2D features are bi-linearly sampled for every voxel based on their projected locations on the images, leading to a voxelized 3D feature map \\(F_{i}^{3\\mathrm{D}}\\). Finally, reducing the Z-axis of \\(F_{i}^{3\\mathrm{D}}\\) produces a BEV feature map \\(F_{i}\\) with shape \\(X\\times Y\\times C\\), where \\(C\\) is the feature dimension." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.821, + 0.47, + 0.882 + ], + "angle": 0, + "content": "Decoder. Our decoder is a fully-convolutional segmentation head that predicts the logits of semantics from every BEV grid in \\( F_{i} \\). It generates the surrounding HD map as the semantic segmentation result \\( S_{i} \\) with shape \\( X \\times Y \\)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.886, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Region-centric extension. Our region-centric design" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.354, + 0.892, + 0.43 + ], + "angle": 0, + "content": "considers each BEV grid as an HD map region. If a grid is covered in \\( N' \\) frames, it receives \\( N' \\) features and predictions from different viewpoints. MV-Map then fuses information from \\( N' \\) view-specific frames to create a multi-view consistent feature for this region, detailed as below." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.436, + 0.882, + 0.453 + ], + "angle": 0, + "content": "4.2. Global Aggregation via Uncertainty Network" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.459, + 0.892, + 0.701 + ], + "angle": 0, + "content": "Region-centric uncertainty-aware fusion. Our region-centric offboard pipeline learns to aggregate the \\(N\\) frames of independent HD map predictions \\(\\{S_i\\}_{i=1}^N\\) into a multiview consistent prediction for each region. Our key design is to introduce an uncertainty network. For the HD map predictions from all viewpoints, the uncertainty network assigns a confidence score to each BEV grid, resulting in \\(N \\times X \\times Y\\) scores that reflect the pairwise reliability of a viewpoint contributing to an HD map region. Specifically, the uncertainty network takes the BEV features \\(\\{F_i\\}_{i=1}^N\\) as input and generates the confidence maps \\(\\{C_i\\}_{i=1}^N\\), with \\(C_i\\) of shape \\(X \\times Y\\). In Sec. 4.3, we will describe how we further incorporate global geometry encoded by Voxel-NeRF into the uncertainty network. The architecture of our uncertainty network is illustrated in Fig. 4, adopting a UNet-like [33] structure for predicting densely on every voxel." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.701, + 0.892, + 0.822 + ], + "angle": 0, + "content": "We then aggregate the per-frame semantics and confidence into a final HD map. Suppose an arbitrary target position \\((x^w, y^w)\\) is specified in the world coordinate system, we transform it to the local coordinate system of every frame with poses \\(\\{P_i\\}_{i=1}^N\\) and sample the semantic maps and confidence scores at corresponding locations. Finally, the prediction for \\((x^w, y^w)\\) is obtained by a weighted average of per-frame semantics according to their confidence." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.892, + 0.902 + ], + "angle": 0, + "content": "KL-divergence loss for enhanced uncertainty learning. In addition to generating confidence scores, we add a multi-layer perceptron (MLP) head to the uncertainty network to infer the KL-divergence between the predicted and ground truth semantics, as shown in Fig. 4. Intuitively, learning to" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "8661" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.088, + 0.096, + 0.434, + 0.226 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.229, + 0.473, + 0.32 + ], + "angle": 0, + "content": "Figure 4: Architecture of uncertainty network, which takes as input the feature map and the augmented 3D positions from NeRF for each voxel (Sec. 4.3). It outputs the confidence maps for region-centric fusion and, optionally, the predicted KL-divergence for the KL-divergence loss (detailed in Sec. 4.2)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.33, + 0.47, + 0.452 + ], + "angle": 0, + "content": "regress the KL-divergence value between the predicted and ground truth HD maps augments the confidence score of the uncertainty network, because a smaller KL-divergence value indicates better quality of map construction and the uncertainty network should assign higher confidence accordingly. During training, we encourage the inferred divergence \\(\\mathrm{KL}^U\\) to be close to the true divergence \\(\\mathrm{KL}^G\\) between semantics \\(S_{i}\\) and \\(S_{i}\\)'s ground truth, formally," + }, + { + "type": "equation", + "bbox": [ + 0.102, + 0.46, + 0.47, + 0.502 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {K L}} = \\frac {1}{X Y} \\sum_ {x = 1} ^ {X} \\sum_ {y = 1} ^ {Y} \\| \\mathrm {K L} ^ {G} [ x, y ] - \\mathrm {K L} ^ {U} [ x, y ] \\| _ {2} ^ {2}. \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.511, + 0.47, + 0.618 + ], + "angle": 0, + "content": "We train the uncertainty network with both a cross-entropy loss between the fusion result and the ground truth semantics at each location \\((x^w, y^w)\\) [13] and our auxiliary KL-divergence loss in Eqn. 1. Given that the weighted average operation is differentiable, the gradients from both of the loss terms can be back-propagated to the confidence scores for updating the uncertainty network." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.621, + 0.419, + 0.637 + ], + "angle": 0, + "content": "4.3. Voxel-NeRF for Multi-view Consistency" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.641, + 0.47, + 0.702 + ], + "angle": 0, + "content": "MV-Map further leverages a voxelized NeRF to effectively construct a unified 3D structure of the scene from the \\(N\\) frames, which is incorporated with the uncertainty network to improve the multi-view consistency of HD maps." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.705, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Voxel-NeRF for traffic scenes. NeRF [22] represents a 3D scene as a continuous function \\( f_{\\mathrm{NeRF}}:(\\mathbf{x},\\theta)\\to (\\mathbf{c},\\sigma) \\), which maps every point \\( x \\) in the 3D space to its color \\( c \\) and density \\( \\sigma \\), relative to the viewing direction \\( \\theta \\). By explicitly encoding camera projection in the neural rendering process, the learned NeRF model \\( f_{\\mathrm{NeRF}} \\) encodes the 3D geometry of the corresponding scene from input images. Despite the success of the vanilla NeRF, applying it to autonomous driving datasets poses significant challenges, because of the unbounded nature of the scenes and the huge quantities of data involved (e.g., 850 scenes on nuScenes [3]). Therefore, we introduce a voxelized NeRF based on DVGO [36] for better training speed and scalability. Our Voxel-NeRF captures" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.258 + ], + "angle": 0, + "content": "multi-view consistent geometry for outdoor scenes, instead of small objects as in conventional NeRFs. To achieve this, we initialize voxel grids with shape \\( X_{s} \\times Y_{s} \\times Z_{s} \\) to cover the entire scene, which is larger than \\( X \\times Y \\times Z \\) used in onboard models for single-frame areas. For each camera ray, the neural rendering operation in Voxel-NeRF concurrently queries every voxel intersected by the ray. This concurrent querying of voxels significantly accelerates the training of our Voxel-NeRF, from hours to minutes for any scene in nuScenes, enabling a reasonable computation budget for MV-Map. More details can be found in Sec. 5." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.261, + 0.893, + 0.58 + ], + "angle": 0, + "content": "Augmenting uncertainty network. Conceptually, the predicted semantics at a position is more reliable when it resides on the object surfaces. Once NeRF produces a multiview consistent structure, we can compute the distance between each voxel center and its closest surface. Such a clue can be exploited to evaluate the reliability of semantic maps. To this end, for an arbitrary \\((x,y)\\) on BEV, we first recover all the voxel center locations at the BEV coordinate \\((x,y)\\) as \\(L_{\\mathrm{Voxel}} = \\{(x,y,z_i)\\}_{i=1}^Z\\) and then compute their corresponding pixel locations on the images \\(L_{\\mathrm{Image}} = \\{(x_i^p,y_i^p)\\}_{i=1}^Z\\). By volume rendering along the camera rays crossing these pixels, \\(f_{\\mathrm{NeRF}}\\) reconstructs the 3D positions of these pixels, denoted as \\(L_{\\mathrm{NeRF}} = \\{(x_i^R,y_i^R,z_i^R)\\}_{i=1}^Z\\), which are generally the intersections between their camera rays and surfaces. (Ray casting details are in Sec. B.2 (Supplementary).) By calculating \\(\\Delta L_{\\mathrm{N/V}} = \\{(x_i^R - x,y_i^R - y,z_i^R - z_i)\\}_{i=1}^Z\\), we assess the consistency between voxel centers and the global 3D structure. Finally, we employ an MLP upon \\(\\Delta L_{\\mathrm{N/V}}\\) and concatenate its output with the BEV feature, which is then used as the augmented input to the uncertainty network, which is the \"augmented 3D positions\" in Fig. 4." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.582, + 0.89, + 0.718 + ], + "angle": 0, + "content": "Dedicating NeRF for HD maps with total-variance loss. Note that our objective is to facilitate HD map generation, rather than optimizing rendering quality. With the majority of HD map elements situated on the ground, we modify the NeRF to focus less on the quality of pixels in the air. To this end, we introduce a simple yet effective \"total-variance loss\" that guides the optimization of near-ground geometry implicitly. This total-variance loss \\(\\mathcal{L}_{\\mathrm{TV}}\\) is obtained by accumulating the total-variance \\(\\mathrm{TV}(\\cdot)\\) at each BEV position:" + }, + { + "type": "equation", + "bbox": [ + 0.582, + 0.739, + 0.892, + 0.782 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {T V}} = - \\frac {1}{X _ {s} Y _ {s}} \\sum_ {x = 1} ^ {X _ {s}} \\sum_ {y = 1} ^ {Y _ {s}} \\operatorname {T V} (x, y). \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.79, + 0.894, + 0.822 + ], + "angle": 0, + "content": "Here the total-variance \\(\\mathrm{TV}(\\cdot)\\) is defined as the L2-norm of the differences of occupancies along the Z-axis, given by" + }, + { + "type": "equation", + "bbox": [ + 0.515, + 0.845, + 0.892, + 0.863 + ], + "angle": 0, + "content": "\\[\n\\operatorname {T V} (x, y) = \\| O [ x, y, 2: Z _ {s} ] - O [ x, y, 1: Z _ {s} - 1 ] \\| _ {2}, \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.87, + 0.892, + 0.902 + ], + "angle": 0, + "content": "where \\( O[x,y,z] \\) represents the density of voxel \\( (x,y,z) \\) predicted by NeRF and \\( \\| \\cdot \\|_2 \\) denotes the L2-norm." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8662" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.089, + 0.895, + 0.137 + ], + "angle": 0, + "content": "Table 1: Comparison with state-of-the-art vision-based HD map generation methods on nuScenes [3]. “*” means the results reported in HDMapNet [13]. “Average Fusion” is an offboard baseline explained in Sec. 5.2. The quantitative results indicate that our MV-Map has significant benefits to HD map generation and outperforms offboard baseline approaches." + }, + { + "type": "table", + "bbox": [ + 0.202, + 0.14, + 0.768, + 0.285 + ], + "angle": 0, + "content": "
SetupMethodmIoU (Short-range / Long-range)
DividerPed CrossingBoundaryAll
OnboardIPM(B)*25.5 / -12.1 / -27.1 / -21.6 / -
IPM(B+C)*38.6 / -19.3 / -39.3 / -32.4 / -
VPN*36.5 / -15.8 / -35.6 / -29.3 / -
Lift-Splat-Shoot [29]*38.3 / -14.9 / -39.3 / -30.8 / -
HMapNet [13]40.6 / 33.918.7 / 19.439.5 / 34.932.9 / 29.4
Onboard Model (Ours)46.4 / 39.329.7 / 26.448.1 / 39.141.4 / 35.0
OffboardAverage Fusion48.86 / 42.8331.55 / 24.7551.98 / 43.9144.13 / 37.16
MV-Map (Ours)50.87 / 48.1534.52 / 33.3455.64 / 50.2847.01 / 43.92
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.296, + 0.471, + 0.388 + ], + "angle": 0, + "content": "We emphasize the \"negative\" sign in Eqn. 2. It indicates \"maximizing\" the variance, because an accurate ground plane has a peak distribution of voxel occupancy on the Z-axis instead of a uniform one. TV-loss enables Voxel-NeRF to assign larger densities to the ground plane than transient objects, leading to high-quality 3D structures as in Fig. 2." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.402, + 0.292, + 0.418 + ], + "angle": 0, + "content": "4.4. Training and Inference" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.425, + 0.47, + 0.502 + ], + "angle": 0, + "content": "The procedure of our offboard pipeline follows three steps: (1) we adopt an existing onboard model, (2) train Voxel-NeRF on sequences, and (3) train and infer the uncertainty network. We describe these steps in order and leave detailed configurations in Sec. G (Supplementary)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.507, + 0.472, + 0.57 + ], + "angle": 0, + "content": "Onboard model. As MV-Map is agnostic to the choice of onboard models (Sec. 4.1), here we adopt an off-the-shelf BEV segmentation model and freeze its parameters during both training and inference stages of the offboard pipeline." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.574, + 0.47, + 0.651 + ], + "angle": 0, + "content": "Voxel-NeRF. We train the Voxel-NeRF for all sequences in our training and validation datasets, using both conventional photometric loss and our total-variance loss (Sec. 4.3). Note that our NeRF training is entirely self-supervised and does not require any annotations." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.657, + 0.47, + 0.779 + ], + "angle": 0, + "content": "Uncertainty network. The region-centric design enables the uncertainty network to handle varying frame numbers of offboard data. In practice, however, the GPU capacities and batching during training limit the network to a fixed and restricted frame number. To overcome this issue, we adopt the solution from video-based tasks (e.g., 2D multi-object tracking [21, 46]), where models are trained on short video clips but are inferred iteratively on unbounded sequences." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.781, + 0.471, + 0.904 + ], + "angle": 0, + "content": "Similarly, given the input \\( N \\) frames of a scene, the uncertainty network is trained with samples containing \\( M(M < N) \\) adjacent frames to fit into limited GPU memory. The loss is a weighted sum of our KL-divergence loss and a BEV segmentation loss (Sec. 4.2). During inference, we apply the uncertainty network to all the \\( N \\) frames independently and use region-centric aggregation to fuse single-frame semantics into a unified HD map." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.295, + 0.634, + 0.311 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.316, + 0.813, + 0.332 + ], + "angle": 0, + "content": "5.1. Dataset and Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.339, + 0.892, + 0.416 + ], + "angle": 0, + "content": "Dataset. We conduct experiments on a large-scale autonomous driving dataset: nuScenes [3]. It contains 850 videos with 28,130 and 6,019 frames for training and validation, respectively. On each timestamp, six surrounding cameras collect high-resolution images as input." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.418, + 0.893, + 0.57 + ], + "angle": 0, + "content": "Evaluation metrics. Following prior work [13], we compute the intersection-over-union (IoU) for HD map categories: divider, pedestrian crossing, and road boundaries. To highlight the challenge of predicting a scene-scale HD map, our evaluation adopts both a short-range setting [13] covering \\(60\\mathrm{m} \\times 30\\mathrm{m}\\) and a new long-range setting covering \\(100\\mathrm{m} \\times 100\\mathrm{m}\\), which aligns with the common perception range in self-driving [7, 9]. Without further mentioning, we conduct our ablation studies under the more challenging long-range setting." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.572, + 0.893, + 0.845 + ], + "angle": 0, + "content": "Implementation details. We follow the training and inference settings in Sec. 4.4 and discuss the details in Sec. G (Supplementary). We emphasize that MV-Map is scalable to large volumes of offboard data. Within 15 minutes on a single A40 GPU, our Voxel-NeRF can optimize the 3D structure from each nuScenes sequence, which typically has over 1k images covering regions with an average length of \\(\\sim 300\\mathrm{m}\\), less than 1 second per frame. In comparison, the common multi-view stereo baseline of COLMAP [34] may take several hours or even days. Notably, this is because COLMAP spent most of the time in feature matching, which is pairwise across frames and \\(\\mathcal{O}(N^2)\\) regarding the frame number \\(N\\). In comparison, the time complexity of NeRF is \\(\\mathcal{O}(N)\\). Moreover, our uncertainty network is trained on the samples with \\(M = 5\\) adjacent frames to fit into our GPU memory, but it can jointly handle all the frames (\\(\\sim 40\\)) in a nuScenes sequence during the inference stage, as explained in Sec. 4.4." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.851, + 0.869, + 0.867 + ], + "angle": 0, + "content": "5.2. Comparison with State-of-the-Art Methods" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.892, + 0.902 + ], + "angle": 0, + "content": "As our work represents the first study on offboard HD map generation, there are no readily available competing" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8663" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.089, + 0.472, + 0.18 + ], + "angle": 0, + "content": "Table 2: MV-Map significantly improves vectorized HD map quality over both the onboard VectorMapNet [18] model and the recent temporal fusion method Neural Map Prior [41] (NMP). \\((\\dagger\\) means the performance reported in NMP; \\(\\ddagger\\) means the performance from VectorMapNet's officially released checkpoint.)" + }, + { + "type": "table", + "bbox": [ + 0.109, + 0.185, + 0.436, + 0.294 + ], + "angle": 0, + "content": "
MethodsmAP
DividerPed CrossingBoundaryAll
VectorMapNet†47.336.139.340.9
+NMP49.642.941.944.8
ΔmAP+2.3+6.8+2.6+3.9
VectorMapNet‡47.739.838.942.1
+MV-Map55.046.245.548.9
Δ mAP+7.3+6.4+6.6+6.7
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.299, + 0.47, + 0.359 + ], + "angle": 0, + "content": "methods. Additionally, our MV-Map can utilize any off-the-shelf onboard model as its internal component. To ensure a meaningful and fair comparison, we organize the experimental results and analysis in Table 1 as follows." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.36, + 0.47, + 0.587 + ], + "angle": 0, + "content": "First, our onboard model adopts the simple-yet-effective design from SimpleBEV [11]. As shown in the \" onboard\" rows, our onboard model already consistently outperforms previous baselines in both short-range and long-range settings. Second, our MV-Map brings a significant improvement of \\(\\sim 7\\%\\) mIoU compared with our already effective onboard model. Notably, our offboard method is better than HDMapNet [13] by around \\(50\\%\\) with over \\(15\\%\\) IoU increase on all the categories. Finally, we develop an offboard baseline algorithm called \"Average Fusion.\" It does not consider the quality of different viewpoints and performs region-centric aggregation by equally averaging the single-frame semantic maps. Compared with \"Average fusion,\" our MV-Map still improves the HD map quality by a large margin of over \\(\\sim 7\\%\\) mIoU under the long-range setting." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.591, + 0.398, + 0.607 + ], + "angle": 0, + "content": "5.3. Comparison on Vectorized HD Maps" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.611, + 0.47, + 0.866 + ], + "angle": 0, + "content": "We further extend our MV-Map to vectorized HD map generation to demonstrate its wide compatibility. In Table 2, we apply MV-Map to VectorMapNet [18], one of the state-of-the-art onboard models generating vectorized HD maps. Specifically, our MV-Map performs uncertainty-aware fusion on the frozen BEV features of an open-sourced VectorMapNet model. The results show that MV-Map improves the HD Map generation quality by a large margin of over \\(\\sim 7\\) mAP, proving its effectiveness in constructing high-quality HD maps. We further compare MV-Map with the recent neural map prior (NMP) [41], which also capitalizes long-term temporal fusion for global HD map generation in Table 2. In the experiments, We adopt the same metric (mAP) as VectorMapNet [18]. As clearly illustrated, our offboard MV-Map pipeline is better in both absolute (48.9 mAP vs. 44.8 mAP) and relative improvements (6.8 mAP vs. 3.9 mAP)." + }, + { + "type": "page_footnote", + "bbox": [ + 0.076, + 0.875, + 0.47, + 0.903 + ], + "angle": 0, + "content": "\\(^{1}\\)NMP is not included for semantic HD map comparison in Sec. 5.2 because it adopts a different resolution for rasterized HD maps." + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.089, + 0.892, + 0.165 + ], + "angle": 0, + "content": "Table 3: The components in MV-Map effectively improve HD map generation step by step. We analyze the uncertainty network (UN) and KL-divergence loss \\((\\mathcal{L}_{\\mathrm{KL}})\\) discussed in Sec. 4.2, and Voxel-NeRF (NeRF) and totalvariance loss \\((\\mathcal{L}_{\\mathrm{TV}})\\) discussed in Sec. 4.3." + }, + { + "type": "table", + "bbox": [ + 0.507, + 0.17, + 0.89, + 0.285 + ], + "angle": 0, + "content": "
IDOffboard ComponentmIoU
UN\\( \\mathcal{L}_{\\text{KL}} \\)NeRF\\( \\mathcal{L}_{\\text{TV}} \\)DividerCrossingBoundaryAll
1Onboard Model39.3026.4439.1034.95
2Average fusion42.8324.7543.9137.16
3✓46.9030.3049.0742.09
4✓✓47.3831.1149.5342.67
5✓✓✓47.6432.3649.6743.22
6✓✓✓48.0132.6550.1243.59
7✓✓✓✓48.1533.3450.2843.92
" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.308, + 0.665, + 0.323 + ], + "angle": 0, + "content": "5.4. Ablation Studies" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.337, + 0.892, + 0.715 + ], + "angle": 0, + "content": "MV-Map Components. We quantify the improvement from each offboard module in Table 3. (1) Region-centric fusion baseline. Beginning from the onboard model (row 1), we first apply average fusion (row 2) to it (discussed in Sec. 5.2) as a baseline. The improvement indicates that our region-centric design indeed helps by fusing numerous frames into a unified HD map. (2) Uncertainty network. Replacing the average fusion (row 2) with the uncertainty network (row 3) enables larger contributions from more reliable frames and the \\(\\sim 5\\%\\) increase in mIoU validates that assessing quality is critical for better HD map quality. (3) KL-divergence loss. The \\(\\sim 0.5\\%\\) mIoU on using KL-divergence loss or not (row 3 and row 4) supports that explicitly supervising the uncertainty network with KL-divergence effectively improves the region-centric fusion to rely on frames with higher quality. (4) Voxel-NeRF. Adding NeRF to a full-fledged uncertainty network further improves the mIoU (row 4 and row 5). In the category-level analysis, we highlight that NeRF is critical for the fusion especially on the challenging structures with smaller regions, e.g., pedestrian crossings. This evidence validates the importance of global geometry in multi-view consistency. (5) Total-variance loss. Utilizing it further boosts the performance in all the scenarios, validating our effort to dedicate NeRFs for the downstream HD map generation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Scaling to more frames. We demonstrate that our fusion strategy can handle and significantly benefit from a larger number of frames, which is critical for offboard HD map generation. We evaluate our offboard framework under varied input frames in Fig. 5. MV-Map can utilize all the keyframes (40 frames) in nuScenes and this number is only bounded by the sequence length. As clearly shown in the blue curve of Fig. 5, MV-Map benefits from more frames, indicating its scalability for offboard scenarios, especially compared with the average fusion baseline, whose performance drops after using more than 15 frames. This indicates that our region-centric fusion strategy is able to" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8664" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.108, + 0.092, + 0.442, + 0.266 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.266, + 0.47, + 0.326 + ], + "angle": 0, + "content": "Figure 5: Our MV-Map can significantly benefit from more input frames, which is attractive for offboard applications. Notably, the performance of the \"average fusion\" baseline saturates and even decreases with more input frames." + }, + { + "type": "image", + "bbox": [ + 0.084, + 0.328, + 0.465, + 0.556 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.572, + 0.47, + 0.618 + ], + "angle": 0, + "content": "Figure 6: Qualitative comparison in the long-range settings. HD map generated offboard has significantly better quality by fixing the artifacts of the onboard model." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.634, + 0.47, + 0.665 + ], + "angle": 0, + "content": "reason the complementary regions among the frames, instead of blindly averaging them all." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.669, + 0.47, + 0.76 + ], + "angle": 0, + "content": "Qualitative comparison. We visualize the generated HD maps in Fig. 6. As clearly shown, MV-Map corrects the artifacts from onboard models and achieves better completeness and details. In addition, the HD maps generated offboard have high fidelity compared with the ground truth, especially in the center regions covered by more frames." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Analyzing KL-divergence and confidence scores. We empirically analyze the output of the uncertainty network in Fig. 7. As for the confidence scores, we observe that they indeed decrease the contributions of unreliable regions, such as the part with occlusion in Fig. 7a, highlighted with solid circles. The invisible area has much smaller confidence than its nearby regions. Additionally, we transfer the KL-divergence prediction head to the validation set and find the predictions reasonably correlate with the confidence scores," + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.092, + 0.889, + 0.285 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.299, + 0.892, + 0.466 + ], + "angle": 0, + "content": "Figure 7: (a) The confidence scores predicted by the uncertainty network capture the challenging regions (solid circles) as the occluded region has significantly smaller confidence values than its nearby regions. Darker colors indicate smaller confidence values. (b) Predicted KL divergence between the prediction and ground truth label captures the connection with the predicted confidence scores (dashed circles). The region with a dashed circle has a much larger predicted KL-divergence value than its nearby regions. Accordingly, this area exhibits smaller confidence scores. Darker colors mean smaller KL-divergence values." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.48, + 0.892, + 0.526 + ], + "angle": 0, + "content": "as in Fig. 7b. We notice that the regions with higher KL-divergence values (Fig. 7b) also have lower confidences (Fig. 7a), highlighted with the dashed circles." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.531, + 0.892, + 0.818 + ], + "angle": 0, + "content": "Using geometric information from data-driven priors. Our Voxel-NeRF offers geometric information in a fully self-supervised manner. Meanwhile, our MV-Map framework is general and can leverage alternative approaches for providing geometric information, such as learning data-driven priors from large-scale datasets. We investigate this type of approach here and consider representative monocular depth estimators that are learned off-the-shelf in a supervised manner. Specifically, we replace the rendering process of Voxel-NeRF with the results from NeWCRFs [45] (details in Sec. G, Supplementary). As in Table 4, monocular depth can improve the uncertainty fusion as well (row 2 and row 3). We further notice that NeRF performs slightly better because it encodes multiple views consistently in a shared 3D structure, while monocular depth considers each view independently and suffers from scale variation across frames. Encouraged by the benefits of these two distinct types of geometric information, future work is to combine NeRF with learnable priors into our framework." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.831, + 0.852, + 0.848 + ], + "angle": 0, + "content": "5.5. Globally Consistent HD Map Generation" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Our offboard MV-Map can handle numerous frames. Its application is to expand the range of HD map generation from a local region around the ego-vehicle to a global re" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8665" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.164, + 0.09, + 0.805, + 0.266 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.276, + 0.893, + 0.308 + ], + "angle": 0, + "content": "Figure 8: Visualization of a unified, scene-scale HD map through our MV-Map. It can fuse numerous frames and generate global-scale HD maps with high quality. It is also robust under different weather conditions and complex road topology." + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.32, + 0.47, + 0.412 + ], + "angle": 0, + "content": "Table 4: MV-Map is a general framework: In addition to NeRF, MV-Map can benefit from data-driven priors of geometric information; here we use monocular depth estimation [45] as an example. \"UN-Only:\" using the uncertainty network without augmentation of 3D structural information. Then we separately incorporate mono-depth or NeRF to it." + }, + { + "type": "table", + "bbox": [ + 0.081, + 0.416, + 0.467, + 0.504 + ], + "angle": 0, + "content": "
MethodsmIoU
DividerPed CrossingBoundaryAll
Average Fusion42.8324.7543.9137.16
MV-Map (UN-Only)47.3831.1149.5342.67
MV-Map (Mono-Depth)48.0432.9650.0843.69
MV-Map (NeRF)48.1533.3450.2843.92
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.514, + 0.47, + 0.59 + ], + "angle": 0, + "content": "Table 5: Performance of incorporating the LiDAR modality in MV-Map, evaluated under the long-range setting on the validation set. As a general framework, MV-Map can exploit multi-modality as input and improve the performance consistently and significantly." + }, + { + "type": "table", + "bbox": [ + 0.084, + 0.595, + 0.462, + 0.668 + ], + "angle": 0, + "content": "
MethodsmIoU (Long-range)
DividerPed CrossingBoundaryAll
Onboard41.6327.1341.6536.80
MV-Map50.7232.9954.6346.11
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.681, + 0.47, + 0.788 + ], + "angle": 0, + "content": "gion covering all the input frames, which saves the labor in stitching multiple local predictions in the real world. Our global maps in Fig. 8 demonstrate high fidelity for complex topology in two challenging scenes. While some regions do not match the ground truth, we argue that these regions fall outside the collected frames and perception ranges, which are beyond the scope of offboard algorithms." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.801, + 0.43, + 0.817 + ], + "angle": 0, + "content": "5.6. Generalizability of MV-Map with LiDAR" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.47, + 0.903 + ], + "angle": 0, + "content": "To demonstrate the generalizability of our framework, we analyze incorporating the LiDAR sensor into MV-Map. In the main paper, we focused on cameras, because they contribute primarily to HD map generation as shown in HDMapNet [13]. On the other hand, LiDARs are also" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.322, + 0.893, + 0.4 + ], + "angle": 0, + "content": "widely used for their accurate distance sensing and their ability to enhance localization, which motivates our investigation here. We first describe the design of utilizing the extra LiDAR modality and then analyze the results. Extra details are explained in Sec. C (Supplementary)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.405, + 0.619, + 0.42 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.423, + 0.893, + 0.68 + ], + "angle": 0, + "content": "Regarding the infrastructure role of HD maps, we propose a novel offboard HD map generation setup to address the unreliability of onboard BEV perception. By removing the computation constraints, the models are allowed to reason all the frames altogether and construct multi-view consistent HD maps. Concretely, we propose an offboard HD map generation framework called MV-Map. To address numerous frames, MV-Map designs region-centric aggregation to unify the HD maps from all the frames. The key design is an uncertainty network that weighs the contribution of different frames and utilizes a Voxel-NeRF to provide multi-view consistent 3D structural information. Experiments validate that MV-Map is scalable to large volumes of offboard data and significantly improves the HD map quality. We hope that our framework can become an effective augmentor for onboard algorithms and also inspire future research on offboard problems." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.683, + 0.893, + 0.804 + ], + "angle": 0, + "content": "Limitations and future work. Although our Voxel-NeRF improves the offboard pipeline in a scalable way, several challenges still present, including moving objects in traffic scenes and exploiting data-driven priors for better geometric information. In addition, we seek to connect our work with auto-labeling and compare it with human annotation quality, so as to explore more potential applications such as autonomous vehicle navigation and urban planning." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.804, + 0.894, + 0.902 + ], + "angle": 0, + "content": "Acknowledgement. This work was supported in part by NSF Grant 2106825, NIFA Award 2020-67021-32799, the Jump ARCHES endowment, the NCSA Fellows program, the Illinois-Inspers Partnership, and the Amazon Research Award. This work used NVIDIA GPUs at NCSA Delta through allocations CIS220014 and CIS230012 from the ACCESS program." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8666" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.115, + 0.468, + 0.143 + ], + "angle": 0, + "content": "[1] Mohamed Aly. Real time detection of lane markers in urban streets. In IEEE Intelligent Vehicles Symposium, 2008. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.145, + 0.469, + 0.185 + ], + "angle": 0, + "content": "[2] Massimo Bertozzi and Alberto Broggi. Real-time lane and obstacle detection on the GOLD system. In IEEE Intelligent Vehicles Symposium, 1996. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.187, + 0.469, + 0.254 + ], + "angle": 0, + "content": "[3] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuScenes: A multimodal dataset for autonomous driving. In CVPR, 2020. 1, 2, 3, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.256, + 0.469, + 0.324 + ], + "angle": 0, + "content": "[4] Ming-Fang Chang, John W Lambert, Patsorn Sangkloy, Jagjeet Singh, Slawomir Bak, Andrew Hartnett, De Wang, Peter Carr, Simon Lucey, Deva Ramanan, and James Hays. Argo-verse: 3D tracking and forecasting with rich maps. In CVPR, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.326, + 0.469, + 0.367 + ], + "angle": 0, + "content": "[5] Kangle Deng, Andrew Liu, Jun-Yan Zhu, and Deva Ramanan. Depth-supervised NeRF: Fewer views and faster training for free. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.369, + 0.469, + 0.422 + ], + "angle": 0, + "content": "[6] Liuuyuan Deng, Ming Yang, Hao Li, Tianyi Li, Bing Hu, and Chunxiang Wang. Restricted deformable convolution-based road scene semantic segmentation using surround view cameras. In ITSC, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.424, + 0.469, + 0.493 + ], + "angle": 0, + "content": "[7] Hao Dong, Xianjing Zhang, Xuan Jiang, Jun Zhang, Jintao Xu, Rui Ai, Weihao Gu, Huimin Lu, Juho Kannala, and Xieyuanli Chen. SuperFusion: Multilevel LiDAR-camera fusion for long-range HD map generation and prediction. arXiv preprint arXiv:2211.15656, 2022. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.495, + 0.469, + 0.591 + ], + "angle": 0, + "content": "[8] Scott Ettinger, Shuyang Cheng, Benjamin Caine, Chenxi Liu, Hang Zhao, Sabeek Pradhan, Yuning Chai, Ben Sapp, Charles R. Qi, Yin Zhou, Zoey Yang, Aur'elien Chouard, Pei Sun, Jiquan Ngiam, Vijay Vasudevan, Alexander McCauley, Jonathon Shlens, and Dragomir Anguelov. Large scale interactive motion forecasting for autonomous driving: The Waymo open motion dataset. In ICCV, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.593, + 0.469, + 0.646 + ], + "angle": 0, + "content": "[9] Lue Fan, Yuxue Yang, Feng Wang, Naiyan Wang, and Zhaoxiang Zhang. Super sparse 3D object detection. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2023. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.649, + 0.469, + 0.689 + ], + "angle": 0, + "content": "[10] Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.691, + 0.469, + 0.732 + ], + "angle": 0, + "content": "[11] Adam W Harley, Zhaoyuan Fang, Jie Li, Rares Ambrus, and Katerina Fragkiadaki. Simple-BEV: What really matters for multi-sensor BEV perception? In ICRA, 2023. 1, 3, 4, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.734, + 0.469, + 0.8 + ], + "angle": 0, + "content": "[12] Anthony Hu, Zak Murez, Nikhil Mohan, Sofia Dudas, Jeffrey Hawke, Vijay Badrinarayanan, Roberto Cipolla, and Alex Kendall. FIERY: Future instance prediction in Bird's-Eye View from surround monocular cameras. In ICCV, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.803, + 0.469, + 0.843 + ], + "angle": 0, + "content": "[13] Qi Li, Yue Wang, Yilun Wang, and Hang Zhao. HDMapNet: An online hd map construction and evaluation framework. In ICRA, 2022. 1, 3, 5, 6, 7, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.469, + 0.899 + ], + "angle": 0, + "content": "[14] Yinhao Li, Zheng Ge, Guanyi Yu, Jinrong Yang, Zengran Wang, Yukang Shi, Jianjian Sun, and Zeming Li. BEVDepth: Acquisition of reliable depth for multi-view 3D object detection. In AAAI, 2023. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.115, + 0.469, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.16 + ], + "angle": 0, + "content": "[15] Zhiqi Li, Wenhai Wang, Hongyang Li, Enze Xie, Chonghao Sima, Tong Lu, Yu Qiao, and Jifeng Dai. BEVFormer: Learning Bird's-Eye-View representation from multi-camera images via spatiotemporal transformers. In ECCV, 2022. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.164, + 0.892, + 0.218 + ], + "angle": 0, + "content": "[16] Benchcheng Liao, Shaoyu Chen, Xinggang Wang, Tianheng Cheng, Qian Zhang, Wenyu Liu, and Chang Huang. MapTR: Structured modeling and learning for online vectorized HD map construction. In ICLR, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.221, + 0.892, + 0.26 + ], + "angle": 0, + "content": "[17] Lingjie Liu, Jiatao Gu, Kyaw Zaw Lin, Tat-Seng Chua, and Christian Theobalt. Neural sparse voxel fields. In NeurIPS, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.263, + 0.892, + 0.304 + ], + "angle": 0, + "content": "[18] Yicheng Liu, Yuan Yuantian, Yue Wang, Yilun Wang, and Hang Zhao. VectorMapNet: End-to-end vectorized HD map learning. In ICML, 2023. 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.306, + 0.892, + 0.36 + ], + "angle": 0, + "content": "[19] Zhijian Liu, Haotian Tang, Alexander Amini, Xingyu Yang, Huizi Mao, Daniela Rus, and Song Han. BEVFusion: Multi-task multi-sensor fusion with unified Bird's-Eye View representation. In ICRA, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.363, + 0.892, + 0.417 + ], + "angle": 0, + "content": "[20] Ricardo Martin-Brualla, Noha Radwan, Mehdi S. M. Sajjadi, Jonathan T. Barron, Alexey Dosovitskiy, and Daniel Duckworth. NeRF in the wild: Neural radiance fields for unconstrained photo collections. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.42, + 0.892, + 0.46 + ], + "angle": 0, + "content": "[21] Tim Meinhardt, Alexander Kirillov, Laura Leal-Taixe, and Christoph Feichtenhofer. TrackFormer: Multi-object tracking with transformers. In CVPR, 2022. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.463, + 0.892, + 0.516 + ], + "angle": 0, + "content": "[22] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan Barron, Ravi Ramamoorthi, and Ren Ng. NeRF: Representing scenes as neural radiance fields for view synthesis. In ECCV, 2020. 2, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.519, + 0.892, + 0.56 + ], + "angle": 0, + "content": "[23] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Trans. Graph., 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.563, + 0.892, + 0.616 + ], + "angle": 0, + "content": "[24] Mahyar Najibi, Jingwei Ji, Yin Zhou, Charles R Qi, Xinchen Yan, Scott Ettinger, and Dragomir Anguelov. Motion inspired unsupervised perception and prediction in autonomous driving. In ECCV, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.619, + 0.892, + 0.699 + ], + "angle": 0, + "content": "[25] Thomas Neff, Pascal Stadlbauer, Mathias Parger, Andreas Kurz, Joerg H. Mueller, Chakravarty R. Alla Chaitanya, Anton S. Kaplanyan, and Markus Steinberger. DONeRF: Towards real-time rendering of compact neural radiance fields using depth oracle networks. In Computer Graphics Forum, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.704, + 0.892, + 0.758 + ], + "angle": 0, + "content": "[26] Mong H. Ng, Kaahan Radia, Jianfei Chen, Dequan Wang, Ionel Gog, and Joseph E Gonzalez. BEV-Seg: Bird's Eye View semantic segmentation using geometry and semantic point cloud. arXiv preprint arXiv:2006.11436, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.761, + 0.892, + 0.813 + ], + "angle": 0, + "content": "[27] Bowen Pan, Jiankai Sun, Ho Yin Tiga Leung, Alex Andonian, and Bolei Zhou. Cross-view semantic segmentation for sensing surroundings. IEEE Robotics and Automation Letters, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.817, + 0.892, + 0.857 + ], + "angle": 0, + "content": "[28] Ziqi Pang, Zhichao Li, and Naiyan Wang. Model-free vehicle tracking and state estimation in point cloud sequences. In IROS, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.86, + 0.892, + 0.899 + ], + "angle": 0, + "content": "[29] Jonah Philion and Sanja Fidler. Lift, Splat, Shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3D. In ECCV, 2020. 3, 6" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8667" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.134 + ], + "angle": 0, + "content": "[30] Charles R Qi, Yin Zhou, Mahyar Najibi, Pei Sun, Khoa Vo, Boyang Deng, and Dragomir Anguelov. Offboard 3D object detection from point cloud sequences. In CVPR, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.134, + 0.471, + 0.203 + ], + "angle": 0, + "content": "[31] Lennart Reiher, Bastian Lampe, and Lutz Eckstein. A Sim2Real deep learning approach for the transformation of images from multiple vehicle-mounted cameras to a semantically segmented image in Bird's Eye View. In ITSC, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.204, + 0.471, + 0.258 + ], + "angle": 0, + "content": "[32] Konstantinos Rematas, Andrew Liu, Pratul P. Srinivasan, Jonathan T. Barron, Andrea Tagliasacchi, Tom Funkhouser, and Vittorio Ferrari. Urban radiance fields. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.259, + 0.471, + 0.315 + ], + "angle": 0, + "content": "[33] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In Medical Image Computing and Computer-Assisted Intervention (MICCAI), 2015. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.316, + 0.471, + 0.343 + ], + "angle": 0, + "content": "[34] Johannes Lutz Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In CVPR, 2016. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.343, + 0.471, + 0.385 + ], + "angle": 0, + "content": "[35] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.385, + 0.471, + 0.427 + ], + "angle": 0, + "content": "[36] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Improved direct voxel grid optimization for radiance fields reconstruction. arXiv preprint arXiv:2206.05085, 2022. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.427, + 0.471, + 0.482 + ], + "angle": 0, + "content": "[37] Matthew Tancik, Vincent Casser, Xinchen Yan, Sabeek Pradhan, Ben Mildenhall, Pratul Srinivasan, Jonathan T. Barron, and Henrik Kretzschmar. Block-NeRF: Scalable large scene neural view synthesis. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.484, + 0.471, + 0.537 + ], + "angle": 0, + "content": "[38] Yi Wei, Shaohui Liu, Yongming Rao, Wang Zhao, Jiwen Lu, and Jie Zhou. NerfingMVS: Guided optimization of neural radiance fields for indoor multi-view stereo. In ICCV, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.538, + 0.471, + 0.649 + ], + "angle": 0, + "content": "[39] Benjamin Wilson, William Qi, Tanmay Agarwal, John Lambert, Jagjeet Singh, Siddhesh Khandelwal, Bowen Pan, Ratnesh Kumar, Andrew Hartnett, Jhony Kaesemodel Pontes, Deva Ramanan, Peter Carr, and James Hays. Argoverse 2: Next generation datasets for self-driving perception and forecasting. In Proceedings of the Neural Information Processing Systems Track on Datasets and Benchmarks (NeurIPS Datasets and Benchmarks 2021, 2023. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.649, + 0.471, + 0.69 + ], + "angle": 0, + "content": "[40] Ziyang Xie, Junge Zhang, Wenye Li, Feihu Zhang, and Li Zhang. S-NeRF: Neural radiance fields for street views. In ICLR, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.691, + 0.471, + 0.733 + ], + "angle": 0, + "content": "[41] Xuan Xiong, Yicheng Liu, Tianyuan Yuan, Yue Wang, Yilun Wang, and Hang Zhao. Neural map prior for autonomous driving. In CVPR, 2023. 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.734, + 0.471, + 0.775 + ], + "angle": 0, + "content": "[42] Qiangeng Xu, Zexiang Xu, Julien Philip, Sai Bi, Zhixin Shu, Kalyan Sunkavalli, and Ulrich Neumann. Point-NeRF: Point-based neural radiance fields. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.776, + 0.471, + 0.817 + ], + "angle": 0, + "content": "[43] Bin Yang, Min Bai, Ming Liang, Wenyuan Zeng, and Raquel Urtasun. Auto4D: Learning to label 4D objects from sequential point clouds. arXiv preprint arXiv:2101.06586, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.471, + 0.858 + ], + "angle": 0, + "content": "[44] Yao Yao, Zixin Luo, Shiwei Li, Tian Fang, and Long Quan. MVSNet: Depth inference for unstructured multiview stereo. In ECCV, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.859, + 0.471, + 0.901 + ], + "angle": 0, + "content": "[45] Weihao Yuan, Xiaodong Gu, Zuozhuo Dai, Siyu Zhu, and Ping Tan. NeWCRFs: Neural window fully-connected CRFs for monocular depth estimation. In CVPR, 2022. 8, 9" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.092, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[46] Fangao Zeng, Bin Dong, Yuang Zhang, Tiancai Wang, Xi-angyu Zhang, and Yichen Wei. MOTR: End-to-end multiple-object tracking with transformer. In ECCV, 2022. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.192 + ], + "angle": 0, + "content": "[47] Xi Zhu, Xiya Cao, Zhiwei Dong, Caifa Zhou, Qiangbo Liu, Wei Li, and Yongliang Wang. Nemo: Neural map growing system for spatiotemporal fusion in bird's-eye-view and bdd-map benchmark. arXiv preprint arXiv:2306.04540, 2023. 3" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.092, + 0.892, + 0.192 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8668" + } + ] +] \ No newline at end of file diff --git a/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/59188c7c-19e6-4a92-b752-2ffcc7690379_origin.pdf b/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/59188c7c-19e6-4a92-b752-2ffcc7690379_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..89b70f2ac8eb1ef078842b992ff8537cf0b2b454 --- /dev/null +++ b/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/59188c7c-19e6-4a92-b752-2ffcc7690379_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:dbcc8a997587920dd066d31b20ebe4e7b49d46d6f691903b54d5c9bbc1214aba +size 7308176 diff --git a/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/full.md b/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/full.md new file mode 100644 index 0000000000000000000000000000000000000000..4938e8299d7514685572300d0ac845eb1f706988 --- /dev/null +++ b/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/full.md @@ -0,0 +1,287 @@ +# MV-Map: Offboard HD Map Generation with Multi-view Consistency + +Ziyang Xie\*1,2 Ziqi Pang\*1 Yu-Xiong Wang $^{1}$ $^{1}$ University of Illinois Urbana-Champaign $^{2}$ Fudan University +{ziyang8, ziqip2, yxw}@illinois.edu + +# Abstract + +While bird's-eye-view (BEV) perception models can be helpful in building high-definition maps (HD maps) with less human labor, their results are often unreliable and demonstrate noticeable inconsistencies in the predicted HD maps from different viewpoints. This is because BEV perception is typically set up in an "onboard" manner, which restricts the computation and prevents algorithms from simultaneously reasoning multiple views. This paper overcomes these limitations and advocates a more practical "offboard" HD map generation setup that removes the computation constraints, based on the fact that HD maps are commonly reusable infrastructures built offline in data centers. To this end, we propose a novel offboard pipeline called MV-Map that capitalizes multi-view consistency and can handle an arbitrary number of frames with the key design of a "region-centric" framework. In MV-Map, the target HD maps are created by aggregating all the frames of onboard predictions, weighted by the confidence scores assigned by an "uncertainty network." To further enhance multi-view consistency, we augment the uncertainty network with the global 3D structure optimized by a voxelized neural radiance field (Voxel-NeRF). Extensive experiments on nuScenes show that our MV-Map significantly improves the quality of HD maps, further highlighting the importance of offboard methods for HD map generation. Our code and model are available at https://github.com/ZiYang-xie/MV-Map. + +# 1. Introduction + +High-definition maps (HD maps) play a crucial role in ensuring the safe navigation of autonomous vehicles, by providing essential positional and semantic information about road elements. Ideally, one would expect the process of constructing HD maps to be as simple as collecting numerous sensory data while driving and then utilizing an automatic algorithm to extract the road elements, + +![](images/d6e579133b4ba25187e6ef94d00293d806862783f46e358bdcd855b6214fe12d.jpg) +Figure 1: Current onboard methods generate unreliable HD map predictions that are inconsistent across multiple views, due to occlusions or viewpoint changes. By contrast, our offboard pipeline constructs a unified and multi-view consistent HD map with clearer lanes. Our key design is a region-centric framework that aggregates single-frame information for each target HD map region. + +as illustrated in Fig. 1. However, the mainstream solutions generally involve human annotators, as seen in widely-used datasets [3, 4, 8, 39]. This design is based on the consideration of the infrastructure role and high re-usability of HD maps, which can serve autonomous vehicles for virtually infinite times after a single construction process before any environmental changes. Even so, the expense of manual annotation obstructs the expansion of autonomous driving to new locations, and we aim to develop reliable algorithms that can decrease or replace the need for human labor in HD map construction. + +Towards this goal, there have been recent attempts that automatically generate HD maps using bird's-eye-view (BEV) perception [11, 13, 15]. However, their results are often unreliable, as illustrated by noticeable inconsistencies in the predicted HD maps from different viewpoints (a representative example is in Fig. 1). We argue that multi-view consistency is an intrinsic property of HD maps, because the rigid and static HD maps shouldn't change significantly after simply switching viewpoints. The violations of consistency arise from the fact that existing BEV perception + +![](images/37ba0b646d97a46811ffa293b1afa6d51c06d8788d81fe62c60951f31aabc4b1.jpg) +Figure 2: Our Voxel-NeRF reconstructs high-quality 3D structure of the scene. As in the rendering result, the lanes and pedestrian crossings (highlighted) are clear. + +algorithms do not account for all the views explicitly and thus do not align their predictions. This issue further boils down to their onboard setting, where the models are only allowed to access computing devices onboard in autonomous vehicles and can only handle a single frame or a few neighboring frames. + +Given such limitations of the onboard setup, we underline a critical yet under-explored offboard setup that removes the computation constraints. Our offboard setting aligns well with the infrastructure role of HD maps: constructing HD maps can and should utilize powerful data centers to maximize the fidelity of predictions, thus ensuring the safety and reliability of the virtually infinite usages of HD maps. By aggregating information from diverse viewpoints and enhancing consistency, our offboard generation provides a natural improvement. As shown in Fig. 1, having multiple views of a shared region offers richer geometric and semantic cues, as well as improves the completeness of scene understanding, particularly regarding frequent occlusions in urban traffic. + +With HD map construction primarily relying on vision information to infer the semantics, which is different from the previous offboard studies depending on point clouds, we are the first to explore a vision-oriented offboard perception framework to our best knowledge. To this end, we propose Multi-view Map (MV-Map) that leverages information from every frame's viewpoint and generates a unified HD map consistent with all of them. In contrast to the frame-centric design in current onboard methods that merges a fixed number of frames on the input level, we propose a region-centric design inspired by "offboard 3D detection" [30] to fully utilize the data from diverse views. Notably, our design can connect every HD map region with an arbitrary number of input frames covering its area. The pipeline of our framework involves extracting all the HD map patches predicted by an off-the-shelf onboard model related to that HD map region, and then fusing the patches into a final result that agrees with all the views, as illustrated in the arrows in Fig. 1. To give more weight to reliable frames, such as those with a clear view of the target region, we introduce an "uncertainty network" as a key component, which assigns confidence scores to onboard results and performs a weighted + +average of HD map patches guided by the confidence. + +We further enhance the consensus among all the frames by augmenting the uncertainty network with cross-view consistency information. Our key insight is to learn a coherent 3D structure from diverse views and provide it as an auxiliary input to the uncertainty network. For this purpose, we exploit neural radiance fields (NeRFs) [22], a state-of-the-art approach that represents 3D structures of scenes. As shown in Fig. 2, our NeRF model synthesizes a high-quality scene structure. Compared with alternative 3D reconstruction strategies like structure from motion (e.g., COLMAP [34]), NeRF is more preferred from a practical perspective, because its runtime grows linearly with the frame number, whereas COLMAP increases quadratically. Moreover, NeRF is fully self-supervised and does not require additional annotations, unlike multi-view stereo methods such as MVSNet [44]. To improve the scalability of NeRF, we leverage a voxelized variant of NeRF (VoxelNeRF) to promote efficiency and propose loss functions that implicitly guide the concentration of NeRF on the near-ground geometry related to HD map generation. Additionally, we highlight NeRF's flexibility and scalability to an arbitrary number of views, making it critical in offboard HD map generation. + +To summarize, we make the following contributions: + +1. We are the first to study the problem of learning to generate HD maps offboard, and we are also the first vision-oriented offboard study to our best knowledge. +2. We propose an effective region-centric framework MV-Map that can generate a multi-view consistent HD map from an arbitrarily large number of frames. +3. We introduce and extend Voxel-NeRF to encode the 3D structure from all frames for HD map generation tasks, further guiding the fusion for multi-view consistency. + +Large-scale experiments on nuScenes [3] show that MV-Map significantly improves HD map quality. Notably, MV-Map can effectively utilize an increasing number of input frames, making it attractive for real-world applications. + +# 2. Related Work + +Offboard 3D perception. The need for large-volume training data encourages developing offboard algorithms. Existing studies mainly focus on predicting 3D bounding boxes [24, 28, 30, 43]. The most representative work on "offboard 3D detection" [30] extracts multi-frame point clouds in object tracks and refines the 3D bounding boxes with the "4D" data. Its success heavily relies on the absolute 3D positions of point clouds, where simply overlaying Li-DAR points can construct denser surfaces of objects. However, in HD map generation that relies on images, it is not straightforward to accumulate imagery data in the 3D space. To overcome this limitation, we propose region-centric fu + +sion to aggregate multi-frame information and utilize multiview reconstruction, e.g. NeRF, to encode global geometry. Our study is also the first vision-oriented offboard pipeline. + +BEV segmentation and HD map construction. Onboard HD map construction is closely related to BEV segmentation, as in HDMapNet [13]. The major challenge in BEV segmentation is to map the image features to the 3D world. The conventional approach leverages inverse perspective warping [1, 2, 6, 27, 31]. BEV perception methods either apply attention to capture the transformation [15, 19], incorporate depth information [12, 14, 26, 29], or directly query the features from voxels [11]. To better support downstream applications, some recent methods [16, 18] have developed special decoders to generate vectorized HD maps. Unlike these onboard methods, our proposition is a general offboard pipeline that utilizes any off-the-shelf segmentation models as an internal component and refines its results with multi-view consistent fusion. In this sense, neural map prior [41] and NeMO [47] also propose to perform long-term temporal fusion, but they primarily focus on an onboard setting and cannot fully leverage the multi-view consistency from long video sequences. Compared with them, our MV-Map is an offboard framework and explicitly accounts for the geometry of diverse views by reconstructing the 3D structure of the scene. + +Neural radiance fields. NeRF [22] has shown outstanding capability in 3D reconstruction. Recent work [20, 32, 37, 40] has extended NeRF into large unbounded scenes, such as city-scale NeRF with ego-centric camera settings [32, 37, 40] and improvement from depth-supervised methods [5, 25, 38, 42]. With NeRF's ability to optimize 3D structures from numerous views, it becomes an ideal method to enforce multi-view consistency for offboard perception. However, as we are the first to adapt NeRF for HD map generation, some important modifications are made. First, we adopt voxel-based NeRF [10, 17, 23, 35, 36] to accelerate the NeRF training by voxelizing the space and encoding the parameters for each position in the voxels. This allows us to reconstruct a huge scene from nuScenes within minutes. In addition, we propose a "total-variance loss" to enhance NeRF's concentration on the near-ground geometry, which also reflects the shift of concentration from pixel quality to downstream HD map generation. + +# 3. Offboard HD Map Generation + +Given a sequence of sensory data, the goal of HD map generation is to predict the positions and semantics of road elements in the BEV space, including road dividers, road boundaries, and pedestrian crossings. + +Problem statement. We consider the input of HD map generation as $\mathcal{D} = \{(I_i, P_i)\}_{i=1}^N$ , where $I_i$ denotes the $i$ -th + +sensor frame, $P_{i}$ is the set of associated sensor poses, and $N$ is the total number of frames in the database representing diverse views of a scene captured by a moving ego vehicle. The output is denoted as $\mathcal{M} = \{M_i\}_{i=1}^N$ , where $M_{i}$ is the HD map for the region nearby the ego vehicle on frame $i$ . Following HDMapNet [13], we define $M_{i}$ as a local semantic map on BEV. Note that the aforementioned formulation is agnostic to sensor types. In the main paper, we mainly focus on vision-oriented HD map generation, and we extend it to leveraging additional LiDAR data in Sec. 5.6. Specifically, every frame $I_{i}$ contains $K = 6$ RGB images $\{I_{i,j}\}_{j=1}^{K}$ on nuScenes [3], and $P_{i} = \{P_{i,j}\}_{j=1}^{K}$ comprises of the intrinsic and extrinsic matrices of corresponding cameras. + +Offboard vs. onboard settings. Compared with the conventional onboard setup, our offboard setup offers greater flexibility in terms of speed and computation resources. Onboard HD map generation algorithms are often constrained by efficiency requirements and cannot use all the $N$ frames in a single run. By contrast, offboard algorithms are allowed to have access to all the $N$ frames, and can then leverage the offline setting and abundant computation resources to generate HD maps of higher quality. + +From frame-centric to region-centric designs. There are different strategies to utilize the temporal data from $N$ frames, similar to offboard 3D detection [30]. A direct solution is frame-centric [30], in which we naively increase the number of frames for existing onboard HD map construction methods, typically BEV segmentation models, and extend them to long sequences. While previous work [13, 15] has illustrated the benefit of longer temporal horizons, a multi-frame BEV segmentation model can only handle a fixed number of input frames, and increasing the frame number requires a linear growth in GPU capacity. Therefore, simply scaling up the input frames of existing onboard models is not an effective way of exploiting the offboard data, which often have varying and large frame numbers. + +To overcome the limitations of the frame-centric design, we propose a novel region-centric design that adaptively aggregates information from an arbitrary number of available frames for each HD map region. Our design is inspired by the object-centric notion in 3D detection [30], but extends to the task of HD map construction. Doing so enables the consensus across frames captured from different viewpoints. + +# 4. Method: Multi-view Map + +Overview. Fig. 3 illustrates the overall framework of our Multi-view Map (MV-Map). An onboard HD map model processes every frame $(I_i, P_i)$ and generates its corresponding BEV feature map $F_i$ and HD map semantics $S_i$ (Sec. 4.1). Then, an uncertainty network assesses the reliability of the single-frame information $F_i$ for every region on the HD map (Sec. 4.2). Meanwhile, a voxelized NeRF + +![](images/95d95c64fca981a4691a46e46e3f4e5446098ce12c95f0d9c648c73e57cf5db6.jpg) +Figure 3: Offboard pipeline of MV-Map. Given an arbitrary number of input frames, MV-Map first leverages an off-the-shelf onboard model to generate BEV features and semantic maps for each frame. Then an uncertainty network predicts their corresponding confidence maps and guides the region-centric aggregation of a unified HD map. Our pipeline further develops a Voxel-NeRF tailored to 3D structures related to HD maps to augment MV-Map with multi-view geometry. + +$f_{\mathrm{NeRF}}$ optimizes a global 3D structure from all $N$ frames and provides multi-view consistency information to the uncertainty network (Sec. 4.3). The final prediction for every region on the HD map is produced by a weighted average of the single-frame semantics $S_{i}$ , which enables handling an arbitrary number of frames. + +# 4.1. Onboard Model + +The onboard model is the entry point of our pipeline. Most existing HD map generation methods follow an encoder-decoder design. The encoder generates a BEV feature map $F_{i}$ from the input $(I_i, P_i)$ as $\mathsf{Encoder}(I_i, P_i) \to F_i$ , and the decoder converts the feature map $F_{i}$ into a semantic map $S_{i}$ as $\mathsf{Decoder}(F_i) \to S_i$ . + +Since our pipeline only requires the BEV feature map $F_{i}$ to activate the subsequent modules, MV-Map is agnostic to specific encoder-decoder designs. Without the loss of generality, we mainly adopt the encoder in SimpleBEV [11] and use a lightweight convolutional decoder. Results based on additional models are in Table D (Supplementary). + +Encoder. For each frame, a convolutional backbone first converts $K$ images $\{I_{i,j}\}_{j = 1}^{K}$ into 2D image feature maps $\{F_{i,j}^{2\mathrm{D}}\}_{j = 1}^{K}$ . The features are then lifted into the 3D world, through a set of voxels that are pre-defined by the encoder with shape $X\times Y\times Z$ centered around the ego vehicle: the 2D features are bi-linearly sampled for every voxel based on their projected locations on the images, leading to a voxelized 3D feature map $F_{i}^{3\mathrm{D}}$ . Finally, reducing the Z-axis of $F_{i}^{3\mathrm{D}}$ produces a BEV feature map $F_{i}$ with shape $X\times Y\times C$ , where $C$ is the feature dimension. + +Decoder. Our decoder is a fully-convolutional segmentation head that predicts the logits of semantics from every BEV grid in $F_{i}$ . It generates the surrounding HD map as the semantic segmentation result $S_{i}$ with shape $X \times Y$ . + +Region-centric extension. Our region-centric design + +considers each BEV grid as an HD map region. If a grid is covered in $N'$ frames, it receives $N'$ features and predictions from different viewpoints. MV-Map then fuses information from $N'$ view-specific frames to create a multi-view consistent feature for this region, detailed as below. + +# 4.2. Global Aggregation via Uncertainty Network + +Region-centric uncertainty-aware fusion. Our region-centric offboard pipeline learns to aggregate the $N$ frames of independent HD map predictions $\{S_i\}_{i=1}^N$ into a multiview consistent prediction for each region. Our key design is to introduce an uncertainty network. For the HD map predictions from all viewpoints, the uncertainty network assigns a confidence score to each BEV grid, resulting in $N \times X \times Y$ scores that reflect the pairwise reliability of a viewpoint contributing to an HD map region. Specifically, the uncertainty network takes the BEV features $\{F_i\}_{i=1}^N$ as input and generates the confidence maps $\{C_i\}_{i=1}^N$ , with $C_i$ of shape $X \times Y$ . In Sec. 4.3, we will describe how we further incorporate global geometry encoded by Voxel-NeRF into the uncertainty network. The architecture of our uncertainty network is illustrated in Fig. 4, adopting a UNet-like [33] structure for predicting densely on every voxel. + +We then aggregate the per-frame semantics and confidence into a final HD map. Suppose an arbitrary target position $(x^w, y^w)$ is specified in the world coordinate system, we transform it to the local coordinate system of every frame with poses $\{P_i\}_{i=1}^N$ and sample the semantic maps and confidence scores at corresponding locations. Finally, the prediction for $(x^w, y^w)$ is obtained by a weighted average of per-frame semantics according to their confidence. + +KL-divergence loss for enhanced uncertainty learning. In addition to generating confidence scores, we add a multi-layer perceptron (MLP) head to the uncertainty network to infer the KL-divergence between the predicted and ground truth semantics, as shown in Fig. 4. Intuitively, learning to + +![](images/0b30b1c42cc3b0917bbfad8d8486595a4bc29e5bba017992e56e89067004e97b.jpg) +Figure 4: Architecture of uncertainty network, which takes as input the feature map and the augmented 3D positions from NeRF for each voxel (Sec. 4.3). It outputs the confidence maps for region-centric fusion and, optionally, the predicted KL-divergence for the KL-divergence loss (detailed in Sec. 4.2). + +regress the KL-divergence value between the predicted and ground truth HD maps augments the confidence score of the uncertainty network, because a smaller KL-divergence value indicates better quality of map construction and the uncertainty network should assign higher confidence accordingly. During training, we encourage the inferred divergence $\mathrm{KL}^U$ to be close to the true divergence $\mathrm{KL}^G$ between semantics $S_{i}$ and $S_{i}$ 's ground truth, formally, + +$$ +\mathcal {L} _ {\mathrm {K L}} = \frac {1}{X Y} \sum_ {x = 1} ^ {X} \sum_ {y = 1} ^ {Y} \| \mathrm {K L} ^ {G} [ x, y ] - \mathrm {K L} ^ {U} [ x, y ] \| _ {2} ^ {2}. \tag {1} +$$ + +We train the uncertainty network with both a cross-entropy loss between the fusion result and the ground truth semantics at each location $(x^w, y^w)$ [13] and our auxiliary KL-divergence loss in Eqn. 1. Given that the weighted average operation is differentiable, the gradients from both of the loss terms can be back-propagated to the confidence scores for updating the uncertainty network. + +# 4.3. Voxel-NeRF for Multi-view Consistency + +MV-Map further leverages a voxelized NeRF to effectively construct a unified 3D structure of the scene from the $N$ frames, which is incorporated with the uncertainty network to improve the multi-view consistency of HD maps. + +Voxel-NeRF for traffic scenes. NeRF [22] represents a 3D scene as a continuous function $f_{\mathrm{NeRF}}:(\mathbf{x},\theta)\to (\mathbf{c},\sigma)$ , which maps every point $x$ in the 3D space to its color $c$ and density $\sigma$ , relative to the viewing direction $\theta$ . By explicitly encoding camera projection in the neural rendering process, the learned NeRF model $f_{\mathrm{NeRF}}$ encodes the 3D geometry of the corresponding scene from input images. Despite the success of the vanilla NeRF, applying it to autonomous driving datasets poses significant challenges, because of the unbounded nature of the scenes and the huge quantities of data involved (e.g., 850 scenes on nuScenes [3]). Therefore, we introduce a voxelized NeRF based on DVGO [36] for better training speed and scalability. Our Voxel-NeRF captures + +multi-view consistent geometry for outdoor scenes, instead of small objects as in conventional NeRFs. To achieve this, we initialize voxel grids with shape $X_{s} \times Y_{s} \times Z_{s}$ to cover the entire scene, which is larger than $X \times Y \times Z$ used in onboard models for single-frame areas. For each camera ray, the neural rendering operation in Voxel-NeRF concurrently queries every voxel intersected by the ray. This concurrent querying of voxels significantly accelerates the training of our Voxel-NeRF, from hours to minutes for any scene in nuScenes, enabling a reasonable computation budget for MV-Map. More details can be found in Sec. 5. + +Augmenting uncertainty network. Conceptually, the predicted semantics at a position is more reliable when it resides on the object surfaces. Once NeRF produces a multiview consistent structure, we can compute the distance between each voxel center and its closest surface. Such a clue can be exploited to evaluate the reliability of semantic maps. To this end, for an arbitrary $(x,y)$ on BEV, we first recover all the voxel center locations at the BEV coordinate $(x,y)$ as $L_{\mathrm{Voxel}} = \{(x,y,z_i)\}_{i=1}^Z$ and then compute their corresponding pixel locations on the images $L_{\mathrm{Image}} = \{(x_i^p,y_i^p)\}_{i=1}^Z$ . By volume rendering along the camera rays crossing these pixels, $f_{\mathrm{NeRF}}$ reconstructs the 3D positions of these pixels, denoted as $L_{\mathrm{NeRF}} = \{(x_i^R,y_i^R,z_i^R)\}_{i=1}^Z$ , which are generally the intersections between their camera rays and surfaces. (Ray casting details are in Sec. B.2 (Supplementary).) By calculating $\Delta L_{\mathrm{N/V}} = \{(x_i^R - x,y_i^R - y,z_i^R - z_i)\}_{i=1}^Z$ , we assess the consistency between voxel centers and the global 3D structure. Finally, we employ an MLP upon $\Delta L_{\mathrm{N/V}}$ and concatenate its output with the BEV feature, which is then used as the augmented input to the uncertainty network, which is the "augmented 3D positions" in Fig. 4. + +Dedicating NeRF for HD maps with total-variance loss. Note that our objective is to facilitate HD map generation, rather than optimizing rendering quality. With the majority of HD map elements situated on the ground, we modify the NeRF to focus less on the quality of pixels in the air. To this end, we introduce a simple yet effective "total-variance loss" that guides the optimization of near-ground geometry implicitly. This total-variance loss $\mathcal{L}_{\mathrm{TV}}$ is obtained by accumulating the total-variance $\mathrm{TV}(\cdot)$ at each BEV position: + +$$ +\mathcal {L} _ {\mathrm {T V}} = - \frac {1}{X _ {s} Y _ {s}} \sum_ {x = 1} ^ {X _ {s}} \sum_ {y = 1} ^ {Y _ {s}} \operatorname {T V} (x, y). \tag {2} +$$ + +Here the total-variance $\mathrm{TV}(\cdot)$ is defined as the L2-norm of the differences of occupancies along the Z-axis, given by + +$$ +\operatorname {T V} (x, y) = \| O [ x, y, 2: Z _ {s} ] - O [ x, y, 1: Z _ {s} - 1 ] \| _ {2}, \tag {3} +$$ + +where $O[x,y,z]$ represents the density of voxel $(x,y,z)$ predicted by NeRF and $\| \cdot \|_2$ denotes the L2-norm. + +Table 1: Comparison with state-of-the-art vision-based HD map generation methods on nuScenes [3]. “*” means the results reported in HDMapNet [13]. “Average Fusion” is an offboard baseline explained in Sec. 5.2. The quantitative results indicate that our MV-Map has significant benefits to HD map generation and outperforms offboard baseline approaches. + +
SetupMethodmIoU (Short-range / Long-range)
DividerPed CrossingBoundaryAll
OnboardIPM(B)*25.5 / -12.1 / -27.1 / -21.6 / -
IPM(B+C)*38.6 / -19.3 / -39.3 / -32.4 / -
VPN*36.5 / -15.8 / -35.6 / -29.3 / -
Lift-Splat-Shoot [29]*38.3 / -14.9 / -39.3 / -30.8 / -
HMapNet [13]40.6 / 33.918.7 / 19.439.5 / 34.932.9 / 29.4
Onboard Model (Ours)46.4 / 39.329.7 / 26.448.1 / 39.141.4 / 35.0
OffboardAverage Fusion48.86 / 42.8331.55 / 24.7551.98 / 43.9144.13 / 37.16
MV-Map (Ours)50.87 / 48.1534.52 / 33.3455.64 / 50.2847.01 / 43.92
+ +We emphasize the "negative" sign in Eqn. 2. It indicates "maximizing" the variance, because an accurate ground plane has a peak distribution of voxel occupancy on the Z-axis instead of a uniform one. TV-loss enables Voxel-NeRF to assign larger densities to the ground plane than transient objects, leading to high-quality 3D structures as in Fig. 2. + +# 4.4. Training and Inference + +The procedure of our offboard pipeline follows three steps: (1) we adopt an existing onboard model, (2) train Voxel-NeRF on sequences, and (3) train and infer the uncertainty network. We describe these steps in order and leave detailed configurations in Sec. G (Supplementary). + +Onboard model. As MV-Map is agnostic to the choice of onboard models (Sec. 4.1), here we adopt an off-the-shelf BEV segmentation model and freeze its parameters during both training and inference stages of the offboard pipeline. + +Voxel-NeRF. We train the Voxel-NeRF for all sequences in our training and validation datasets, using both conventional photometric loss and our total-variance loss (Sec. 4.3). Note that our NeRF training is entirely self-supervised and does not require any annotations. + +Uncertainty network. The region-centric design enables the uncertainty network to handle varying frame numbers of offboard data. In practice, however, the GPU capacities and batching during training limit the network to a fixed and restricted frame number. To overcome this issue, we adopt the solution from video-based tasks (e.g., 2D multi-object tracking [21, 46]), where models are trained on short video clips but are inferred iteratively on unbounded sequences. + +Similarly, given the input $N$ frames of a scene, the uncertainty network is trained with samples containing $M(M < N)$ adjacent frames to fit into limited GPU memory. The loss is a weighted sum of our KL-divergence loss and a BEV segmentation loss (Sec. 4.2). During inference, we apply the uncertainty network to all the $N$ frames independently and use region-centric aggregation to fuse single-frame semantics into a unified HD map. + +# 5. Experiments + +# 5.1. Dataset and Implementation Details + +Dataset. We conduct experiments on a large-scale autonomous driving dataset: nuScenes [3]. It contains 850 videos with 28,130 and 6,019 frames for training and validation, respectively. On each timestamp, six surrounding cameras collect high-resolution images as input. + +Evaluation metrics. Following prior work [13], we compute the intersection-over-union (IoU) for HD map categories: divider, pedestrian crossing, and road boundaries. To highlight the challenge of predicting a scene-scale HD map, our evaluation adopts both a short-range setting [13] covering $60\mathrm{m} \times 30\mathrm{m}$ and a new long-range setting covering $100\mathrm{m} \times 100\mathrm{m}$ , which aligns with the common perception range in self-driving [7, 9]. Without further mentioning, we conduct our ablation studies under the more challenging long-range setting. + +Implementation details. We follow the training and inference settings in Sec. 4.4 and discuss the details in Sec. G (Supplementary). We emphasize that MV-Map is scalable to large volumes of offboard data. Within 15 minutes on a single A40 GPU, our Voxel-NeRF can optimize the 3D structure from each nuScenes sequence, which typically has over 1k images covering regions with an average length of $\sim 300\mathrm{m}$ , less than 1 second per frame. In comparison, the common multi-view stereo baseline of COLMAP [34] may take several hours or even days. Notably, this is because COLMAP spent most of the time in feature matching, which is pairwise across frames and $\mathcal{O}(N^2)$ regarding the frame number $N$ . In comparison, the time complexity of NeRF is $\mathcal{O}(N)$ . Moreover, our uncertainty network is trained on the samples with $M = 5$ adjacent frames to fit into our GPU memory, but it can jointly handle all the frames ( $\sim 40$ ) in a nuScenes sequence during the inference stage, as explained in Sec. 4.4. + +# 5.2. Comparison with State-of-the-Art Methods + +As our work represents the first study on offboard HD map generation, there are no readily available competing + +Table 2: MV-Map significantly improves vectorized HD map quality over both the onboard VectorMapNet [18] model and the recent temporal fusion method Neural Map Prior [41] (NMP). $(\dagger$ means the performance reported in NMP; $\ddagger$ means the performance from VectorMapNet's officially released checkpoint.) + +
MethodsmAP
DividerPed CrossingBoundaryAll
VectorMapNet†47.336.139.340.9
+NMP49.642.941.944.8
ΔmAP+2.3+6.8+2.6+3.9
VectorMapNet‡47.739.838.942.1
+MV-Map55.046.245.548.9
Δ mAP+7.3+6.4+6.6+6.7
+ +methods. Additionally, our MV-Map can utilize any off-the-shelf onboard model as its internal component. To ensure a meaningful and fair comparison, we organize the experimental results and analysis in Table 1 as follows. + +First, our onboard model adopts the simple-yet-effective design from SimpleBEV [11]. As shown in the " onboard" rows, our onboard model already consistently outperforms previous baselines in both short-range and long-range settings. Second, our MV-Map brings a significant improvement of $\sim 7\%$ mIoU compared with our already effective onboard model. Notably, our offboard method is better than HDMapNet [13] by around $50\%$ with over $15\%$ IoU increase on all the categories. Finally, we develop an offboard baseline algorithm called "Average Fusion." It does not consider the quality of different viewpoints and performs region-centric aggregation by equally averaging the single-frame semantic maps. Compared with "Average fusion," our MV-Map still improves the HD map quality by a large margin of over $\sim 7\%$ mIoU under the long-range setting. + +# 5.3. Comparison on Vectorized HD Maps + +We further extend our MV-Map to vectorized HD map generation to demonstrate its wide compatibility. In Table 2, we apply MV-Map to VectorMapNet [18], one of the state-of-the-art onboard models generating vectorized HD maps. Specifically, our MV-Map performs uncertainty-aware fusion on the frozen BEV features of an open-sourced VectorMapNet model. The results show that MV-Map improves the HD Map generation quality by a large margin of over $\sim 7$ mAP, proving its effectiveness in constructing high-quality HD maps. We further compare MV-Map with the recent neural map prior (NMP) [41], which also capitalizes long-term temporal fusion for global HD map generation in Table 2. In the experiments, We adopt the same metric (mAP) as VectorMapNet [18]. As clearly illustrated, our offboard MV-Map pipeline is better in both absolute (48.9 mAP vs. 44.8 mAP) and relative improvements (6.8 mAP vs. 3.9 mAP). + +Table 3: The components in MV-Map effectively improve HD map generation step by step. We analyze the uncertainty network (UN) and KL-divergence loss $(\mathcal{L}_{\mathrm{KL}})$ discussed in Sec. 4.2, and Voxel-NeRF (NeRF) and totalvariance loss $(\mathcal{L}_{\mathrm{TV}})$ discussed in Sec. 4.3. + +
IDOffboard ComponentmIoU
UN\( \mathcal{L}_{\text{KL}} \)NeRF\( \mathcal{L}_{\text{TV}} \)DividerCrossingBoundaryAll
1Onboard Model39.3026.4439.1034.95
2Average fusion42.8324.7543.9137.16
3✓46.9030.3049.0742.09
4✓✓47.3831.1149.5342.67
5✓✓✓47.6432.3649.6743.22
6✓✓✓48.0132.6550.1243.59
7✓✓✓✓48.1533.3450.2843.92
+ +# 5.4. Ablation Studies + +MV-Map Components. We quantify the improvement from each offboard module in Table 3. (1) Region-centric fusion baseline. Beginning from the onboard model (row 1), we first apply average fusion (row 2) to it (discussed in Sec. 5.2) as a baseline. The improvement indicates that our region-centric design indeed helps by fusing numerous frames into a unified HD map. (2) Uncertainty network. Replacing the average fusion (row 2) with the uncertainty network (row 3) enables larger contributions from more reliable frames and the $\sim 5\%$ increase in mIoU validates that assessing quality is critical for better HD map quality. (3) KL-divergence loss. The $\sim 0.5\%$ mIoU on using KL-divergence loss or not (row 3 and row 4) supports that explicitly supervising the uncertainty network with KL-divergence effectively improves the region-centric fusion to rely on frames with higher quality. (4) Voxel-NeRF. Adding NeRF to a full-fledged uncertainty network further improves the mIoU (row 4 and row 5). In the category-level analysis, we highlight that NeRF is critical for the fusion especially on the challenging structures with smaller regions, e.g., pedestrian crossings. This evidence validates the importance of global geometry in multi-view consistency. (5) Total-variance loss. Utilizing it further boosts the performance in all the scenarios, validating our effort to dedicate NeRFs for the downstream HD map generation. + +Scaling to more frames. We demonstrate that our fusion strategy can handle and significantly benefit from a larger number of frames, which is critical for offboard HD map generation. We evaluate our offboard framework under varied input frames in Fig. 5. MV-Map can utilize all the keyframes (40 frames) in nuScenes and this number is only bounded by the sequence length. As clearly shown in the blue curve of Fig. 5, MV-Map benefits from more frames, indicating its scalability for offboard scenarios, especially compared with the average fusion baseline, whose performance drops after using more than 15 frames. This indicates that our region-centric fusion strategy is able to + +![](images/f8ccfd58057f755d85868db82752e779100ba64f07cbe7c9d987cc9512a8beee.jpg) +Figure 5: Our MV-Map can significantly benefit from more input frames, which is attractive for offboard applications. Notably, the performance of the "average fusion" baseline saturates and even decreases with more input frames. + +![](images/c4885b7a41cc4c5b87b1b581e9334bd2b9af6ec538b2cc2bd412a16176c6b361.jpg) +Figure 6: Qualitative comparison in the long-range settings. HD map generated offboard has significantly better quality by fixing the artifacts of the onboard model. + +reason the complementary regions among the frames, instead of blindly averaging them all. + +Qualitative comparison. We visualize the generated HD maps in Fig. 6. As clearly shown, MV-Map corrects the artifacts from onboard models and achieves better completeness and details. In addition, the HD maps generated offboard have high fidelity compared with the ground truth, especially in the center regions covered by more frames. + +Analyzing KL-divergence and confidence scores. We empirically analyze the output of the uncertainty network in Fig. 7. As for the confidence scores, we observe that they indeed decrease the contributions of unreliable regions, such as the part with occlusion in Fig. 7a, highlighted with solid circles. The invisible area has much smaller confidence than its nearby regions. Additionally, we transfer the KL-divergence prediction head to the validation set and find the predictions reasonably correlate with the confidence scores, + +![](images/cb82f8c971dc62d190b3c944ba60267ae396f7b132aa1fd0aeb6aa10d9e4acfe.jpg) +Figure 7: (a) The confidence scores predicted by the uncertainty network capture the challenging regions (solid circles) as the occluded region has significantly smaller confidence values than its nearby regions. Darker colors indicate smaller confidence values. (b) Predicted KL divergence between the prediction and ground truth label captures the connection with the predicted confidence scores (dashed circles). The region with a dashed circle has a much larger predicted KL-divergence value than its nearby regions. Accordingly, this area exhibits smaller confidence scores. Darker colors mean smaller KL-divergence values. + +as in Fig. 7b. We notice that the regions with higher KL-divergence values (Fig. 7b) also have lower confidences (Fig. 7a), highlighted with the dashed circles. + +Using geometric information from data-driven priors. Our Voxel-NeRF offers geometric information in a fully self-supervised manner. Meanwhile, our MV-Map framework is general and can leverage alternative approaches for providing geometric information, such as learning data-driven priors from large-scale datasets. We investigate this type of approach here and consider representative monocular depth estimators that are learned off-the-shelf in a supervised manner. Specifically, we replace the rendering process of Voxel-NeRF with the results from NeWCRFs [45] (details in Sec. G, Supplementary). As in Table 4, monocular depth can improve the uncertainty fusion as well (row 2 and row 3). We further notice that NeRF performs slightly better because it encodes multiple views consistently in a shared 3D structure, while monocular depth considers each view independently and suffers from scale variation across frames. Encouraged by the benefits of these two distinct types of geometric information, future work is to combine NeRF with learnable priors into our framework. + +# 5.5. Globally Consistent HD Map Generation + +Our offboard MV-Map can handle numerous frames. Its application is to expand the range of HD map generation from a local region around the ego-vehicle to a global re + +![](images/55429bb0e6b5838c37e918a69ecaf9b7f40fe7327e076b975cb4ce9c85958b86.jpg) +Figure 8: Visualization of a unified, scene-scale HD map through our MV-Map. It can fuse numerous frames and generate global-scale HD maps with high quality. It is also robust under different weather conditions and complex road topology. + +Table 4: MV-Map is a general framework: In addition to NeRF, MV-Map can benefit from data-driven priors of geometric information; here we use monocular depth estimation [45] as an example. "UN-Only:" using the uncertainty network without augmentation of 3D structural information. Then we separately incorporate mono-depth or NeRF to it. + +
MethodsmIoU
DividerPed CrossingBoundaryAll
Average Fusion42.8324.7543.9137.16
MV-Map (UN-Only)47.3831.1149.5342.67
MV-Map (Mono-Depth)48.0432.9650.0843.69
MV-Map (NeRF)48.1533.3450.2843.92
+ +Table 5: Performance of incorporating the LiDAR modality in MV-Map, evaluated under the long-range setting on the validation set. As a general framework, MV-Map can exploit multi-modality as input and improve the performance consistently and significantly. + +
MethodsmIoU (Long-range)
DividerPed CrossingBoundaryAll
Onboard41.6327.1341.6536.80
MV-Map50.7232.9954.6346.11
+ +gion covering all the input frames, which saves the labor in stitching multiple local predictions in the real world. Our global maps in Fig. 8 demonstrate high fidelity for complex topology in two challenging scenes. While some regions do not match the ground truth, we argue that these regions fall outside the collected frames and perception ranges, which are beyond the scope of offboard algorithms. + +# 5.6. Generalizability of MV-Map with LiDAR + +To demonstrate the generalizability of our framework, we analyze incorporating the LiDAR sensor into MV-Map. In the main paper, we focused on cameras, because they contribute primarily to HD map generation as shown in HDMapNet [13]. On the other hand, LiDARs are also + +widely used for their accurate distance sensing and their ability to enhance localization, which motivates our investigation here. We first describe the design of utilizing the extra LiDAR modality and then analyze the results. Extra details are explained in Sec. C (Supplementary). + +# 6. Conclusion + +Regarding the infrastructure role of HD maps, we propose a novel offboard HD map generation setup to address the unreliability of onboard BEV perception. By removing the computation constraints, the models are allowed to reason all the frames altogether and construct multi-view consistent HD maps. Concretely, we propose an offboard HD map generation framework called MV-Map. To address numerous frames, MV-Map designs region-centric aggregation to unify the HD maps from all the frames. The key design is an uncertainty network that weighs the contribution of different frames and utilizes a Voxel-NeRF to provide multi-view consistent 3D structural information. Experiments validate that MV-Map is scalable to large volumes of offboard data and significantly improves the HD map quality. We hope that our framework can become an effective augmentor for onboard algorithms and also inspire future research on offboard problems. + +Limitations and future work. Although our Voxel-NeRF improves the offboard pipeline in a scalable way, several challenges still present, including moving objects in traffic scenes and exploiting data-driven priors for better geometric information. In addition, we seek to connect our work with auto-labeling and compare it with human annotation quality, so as to explore more potential applications such as autonomous vehicle navigation and urban planning. + +Acknowledgement. This work was supported in part by NSF Grant 2106825, NIFA Award 2020-67021-32799, the Jump ARCHES endowment, the NCSA Fellows program, the Illinois-Inspers Partnership, and the Amazon Research Award. This work used NVIDIA GPUs at NCSA Delta through allocations CIS220014 and CIS230012 from the ACCESS program. + +# References + +[1] Mohamed Aly. Real time detection of lane markers in urban streets. In IEEE Intelligent Vehicles Symposium, 2008. 3 +[2] Massimo Bertozzi and Alberto Broggi. Real-time lane and obstacle detection on the GOLD system. In IEEE Intelligent Vehicles Symposium, 1996. 3 +[3] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuScenes: A multimodal dataset for autonomous driving. In CVPR, 2020. 1, 2, 3, 5, 6 +[4] Ming-Fang Chang, John W Lambert, Patsorn Sangkloy, Jagjeet Singh, Slawomir Bak, Andrew Hartnett, De Wang, Peter Carr, Simon Lucey, Deva Ramanan, and James Hays. Argo-verse: 3D tracking and forecasting with rich maps. In CVPR, 2019. 1 +[5] Kangle Deng, Andrew Liu, Jun-Yan Zhu, and Deva Ramanan. Depth-supervised NeRF: Fewer views and faster training for free. In CVPR, 2022. 3 +[6] Liuuyuan Deng, Ming Yang, Hao Li, Tianyi Li, Bing Hu, and Chunxiang Wang. Restricted deformable convolution-based road scene semantic segmentation using surround view cameras. In ITSC, 2020. 3 +[7] Hao Dong, Xianjing Zhang, Xuan Jiang, Jun Zhang, Jintao Xu, Rui Ai, Weihao Gu, Huimin Lu, Juho Kannala, and Xieyuanli Chen. SuperFusion: Multilevel LiDAR-camera fusion for long-range HD map generation and prediction. arXiv preprint arXiv:2211.15656, 2022. 6 +[8] Scott Ettinger, Shuyang Cheng, Benjamin Caine, Chenxi Liu, Hang Zhao, Sabeek Pradhan, Yuning Chai, Ben Sapp, Charles R. Qi, Yin Zhou, Zoey Yang, Aur'elien Chouard, Pei Sun, Jiquan Ngiam, Vijay Vasudevan, Alexander McCauley, Jonathon Shlens, and Dragomir Anguelov. Large scale interactive motion forecasting for autonomous driving: The Waymo open motion dataset. In ICCV, 2021. 1 +[9] Lue Fan, Yuxue Yang, Feng Wang, Naiyan Wang, and Zhaoxiang Zhang. Super sparse 3D object detection. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2023. 6 +[10] Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, 2022. 3 +[11] Adam W Harley, Zhaoyuan Fang, Jie Li, Rares Ambrus, and Katerina Fragkiadaki. Simple-BEV: What really matters for multi-sensor BEV perception? In ICRA, 2023. 1, 3, 4, 7 +[12] Anthony Hu, Zak Murez, Nikhil Mohan, Sofia Dudas, Jeffrey Hawke, Vijay Badrinarayanan, Roberto Cipolla, and Alex Kendall. FIERY: Future instance prediction in Bird's-Eye View from surround monocular cameras. In ICCV, 2021. 3 +[13] Qi Li, Yue Wang, Yilun Wang, and Hang Zhao. HDMapNet: An online hd map construction and evaluation framework. In ICRA, 2022. 1, 3, 5, 6, 7, 9 +[14] Yinhao Li, Zheng Ge, Guanyi Yu, Jinrong Yang, Zengran Wang, Yukang Shi, Jianjian Sun, and Zeming Li. BEVDepth: Acquisition of reliable depth for multi-view 3D object detection. In AAAI, 2023. 3 + +[15] Zhiqi Li, Wenhai Wang, Hongyang Li, Enze Xie, Chonghao Sima, Tong Lu, Yu Qiao, and Jifeng Dai. BEVFormer: Learning Bird's-Eye-View representation from multi-camera images via spatiotemporal transformers. In ECCV, 2022. 1, 3 +[16] Benchcheng Liao, Shaoyu Chen, Xinggang Wang, Tianheng Cheng, Qian Zhang, Wenyu Liu, and Chang Huang. MapTR: Structured modeling and learning for online vectorized HD map construction. In ICLR, 2023. 3 +[17] Lingjie Liu, Jiatao Gu, Kyaw Zaw Lin, Tat-Seng Chua, and Christian Theobalt. Neural sparse voxel fields. In NeurIPS, 2020. 3 +[18] Yicheng Liu, Yuan Yuantian, Yue Wang, Yilun Wang, and Hang Zhao. VectorMapNet: End-to-end vectorized HD map learning. In ICML, 2023. 3, 7 +[19] Zhijian Liu, Haotian Tang, Alexander Amini, Xingyu Yang, Huizi Mao, Daniela Rus, and Song Han. BEVFusion: Multi-task multi-sensor fusion with unified Bird's-Eye View representation. In ICRA, 2023. 3 +[20] Ricardo Martin-Brualla, Noha Radwan, Mehdi S. M. Sajjadi, Jonathan T. Barron, Alexey Dosovitskiy, and Daniel Duckworth. NeRF in the wild: Neural radiance fields for unconstrained photo collections. In CVPR, 2021. 3 +[21] Tim Meinhardt, Alexander Kirillov, Laura Leal-Taixe, and Christoph Feichtenhofer. TrackFormer: Multi-object tracking with transformers. In CVPR, 2022. 6 +[22] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan Barron, Ravi Ramamoorthi, and Ren Ng. NeRF: Representing scenes as neural radiance fields for view synthesis. In ECCV, 2020. 2, 3, 5 +[23] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Trans. Graph., 2022. 3 +[24] Mahyar Najibi, Jingwei Ji, Yin Zhou, Charles R Qi, Xinchen Yan, Scott Ettinger, and Dragomir Anguelov. Motion inspired unsupervised perception and prediction in autonomous driving. In ECCV, 2022. 2 +[25] Thomas Neff, Pascal Stadlbauer, Mathias Parger, Andreas Kurz, Joerg H. Mueller, Chakravarty R. Alla Chaitanya, Anton S. Kaplanyan, and Markus Steinberger. DONeRF: Towards real-time rendering of compact neural radiance fields using depth oracle networks. In Computer Graphics Forum, 2021. 3 +[26] Mong H. Ng, Kaahan Radia, Jianfei Chen, Dequan Wang, Ionel Gog, and Joseph E Gonzalez. BEV-Seg: Bird's Eye View semantic segmentation using geometry and semantic point cloud. arXiv preprint arXiv:2006.11436, 2020. 3 +[27] Bowen Pan, Jiankai Sun, Ho Yin Tiga Leung, Alex Andonian, and Bolei Zhou. Cross-view semantic segmentation for sensing surroundings. IEEE Robotics and Automation Letters, 2020. 3 +[28] Ziqi Pang, Zhichao Li, and Naiyan Wang. Model-free vehicle tracking and state estimation in point cloud sequences. In IROS, 2021. 2 +[29] Jonah Philion and Sanja Fidler. Lift, Splat, Shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3D. In ECCV, 2020. 3, 6 + +[30] Charles R Qi, Yin Zhou, Mahyar Najibi, Pei Sun, Khoa Vo, Boyang Deng, and Dragomir Anguelov. Offboard 3D object detection from point cloud sequences. In CVPR, 2021. 2, 3 +[31] Lennart Reiher, Bastian Lampe, and Lutz Eckstein. A Sim2Real deep learning approach for the transformation of images from multiple vehicle-mounted cameras to a semantically segmented image in Bird's Eye View. In ITSC, 2020. 3 +[32] Konstantinos Rematas, Andrew Liu, Pratul P. Srinivasan, Jonathan T. Barron, Andrea Tagliasacchi, Tom Funkhouser, and Vittorio Ferrari. Urban radiance fields. In CVPR, 2022. 3 +[33] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In Medical Image Computing and Computer-Assisted Intervention (MICCAI), 2015. 4 +[34] Johannes Lutz Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In CVPR, 2016. 2, 6 +[35] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In CVPR, 2022. 3 +[36] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Improved direct voxel grid optimization for radiance fields reconstruction. arXiv preprint arXiv:2206.05085, 2022. 3, 5 +[37] Matthew Tancik, Vincent Casser, Xinchen Yan, Sabeek Pradhan, Ben Mildenhall, Pratul Srinivasan, Jonathan T. Barron, and Henrik Kretzschmar. Block-NeRF: Scalable large scene neural view synthesis. In CVPR, 2022. 3 +[38] Yi Wei, Shaohui Liu, Yongming Rao, Wang Zhao, Jiwen Lu, and Jie Zhou. NerfingMVS: Guided optimization of neural radiance fields for indoor multi-view stereo. In ICCV, 2021. 3 +[39] Benjamin Wilson, William Qi, Tanmay Agarwal, John Lambert, Jagjeet Singh, Siddhesh Khandelwal, Bowen Pan, Ratnesh Kumar, Andrew Hartnett, Jhony Kaesemodel Pontes, Deva Ramanan, Peter Carr, and James Hays. Argoverse 2: Next generation datasets for self-driving perception and forecasting. In Proceedings of the Neural Information Processing Systems Track on Datasets and Benchmarks (NeurIPS Datasets and Benchmarks 2021, 2023. 1 +[40] Ziyang Xie, Junge Zhang, Wenye Li, Feihu Zhang, and Li Zhang. S-NeRF: Neural radiance fields for street views. In ICLR, 2023. 3 +[41] Xuan Xiong, Yicheng Liu, Tianyuan Yuan, Yue Wang, Yilun Wang, and Hang Zhao. Neural map prior for autonomous driving. In CVPR, 2023. 3, 7 +[42] Qiangeng Xu, Zexiang Xu, Julien Philip, Sai Bi, Zhixin Shu, Kalyan Sunkavalli, and Ulrich Neumann. Point-NeRF: Point-based neural radiance fields. In CVPR, 2022. 3 +[43] Bin Yang, Min Bai, Ming Liang, Wenyuan Zeng, and Raquel Urtasun. Auto4D: Learning to label 4D objects from sequential point clouds. arXiv preprint arXiv:2101.06586, 2021. 2 +[44] Yao Yao, Zixin Luo, Shiwei Li, Tian Fang, and Long Quan. MVSNet: Depth inference for unstructured multiview stereo. In ECCV, 2018. 2 +[45] Weihao Yuan, Xiaodong Gu, Zuozhuo Dai, Siyu Zhu, and Ping Tan. NeWCRFs: Neural window fully-connected CRFs for monocular depth estimation. In CVPR, 2022. 8, 9 + +[46] Fangao Zeng, Bin Dong, Yuang Zhang, Tiancai Wang, Xi-angyu Zhang, and Yichen Wei. MOTR: End-to-end multiple-object tracking with transformer. In ECCV, 2022. 6 +[47] Xi Zhu, Xiya Cao, Zhiwei Dong, Caifa Zhou, Qiangbo Liu, Wei Li, and Yongliang Wang. Nemo: Neural map growing system for spatiotemporal fusion in bird's-eye-view and bdd-map benchmark. arXiv preprint arXiv:2306.04540, 2023. 3 \ No newline at end of file diff --git a/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/images.zip b/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..d7bab72057904d25cba94311bd0359c613d368b3 --- /dev/null +++ b/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:97fcfb64381ee59071b11bb7ca97076ae94937b99e54ffc9ae6d3eb3a41110aa +size 504994 diff --git a/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/layout.json b/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..feea29c91251e47755c385468ab100e766d90de9 --- /dev/null +++ b/2023/MV-Map_ Offboard HD-Map Generation with Multi-view Consistency/layout.json @@ -0,0 +1,8517 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 79, + 103, + 514, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 79, + 103, + 514, + 121 + ], + "spans": [ + { + "bbox": [ + 79, + 103, + 514, + 121 + ], + "type": "text", + "content": "MV-Map: Offboard HD Map Generation with Multi-view Consistency" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 137, + 142, + 457, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 137, + 142, + 457, + 185 + ], + "spans": [ + { + "bbox": [ + 137, + 142, + 457, + 185 + ], + "type": "text", + "content": "Ziyang Xie\\*1,2 Ziqi Pang\\*1 Yu-Xiong Wang" + }, + { + "bbox": [ + 137, + 142, + 457, + 185 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 137, + 142, + 457, + 185 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 137, + 142, + 457, + 185 + ], + "type": "text", + "content": "University of Illinois Urbana-Champaign " + }, + { + "bbox": [ + 137, + 142, + 457, + 185 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 137, + 142, + 457, + 185 + ], + "type": "text", + "content": "Fudan University \n{ziyang8, ziqip2, yxw}@illinois.edu" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "spans": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 239, + 290, + 562 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 239, + 290, + 562 + ], + "spans": [ + { + "bbox": [ + 47, + 239, + 290, + 562 + ], + "type": "text", + "content": "While bird's-eye-view (BEV) perception models can be helpful in building high-definition maps (HD maps) with less human labor, their results are often unreliable and demonstrate noticeable inconsistencies in the predicted HD maps from different viewpoints. This is because BEV perception is typically set up in an \"onboard\" manner, which restricts the computation and prevents algorithms from simultaneously reasoning multiple views. This paper overcomes these limitations and advocates a more practical \"offboard\" HD map generation setup that removes the computation constraints, based on the fact that HD maps are commonly reusable infrastructures built offline in data centers. To this end, we propose a novel offboard pipeline called MV-Map that capitalizes multi-view consistency and can handle an arbitrary number of frames with the key design of a \"region-centric\" framework. In MV-Map, the target HD maps are created by aggregating all the frames of onboard predictions, weighted by the confidence scores assigned by an \"uncertainty network.\" To further enhance multi-view consistency, we augment the uncertainty network with the global 3D structure optimized by a voxelized neural radiance field (Voxel-NeRF). Extensive experiments on nuScenes show that our MV-Map significantly improves the quality of HD maps, further highlighting the importance of offboard methods for HD map generation. Our code and model are available at https://github.com/ZiYang-xie/MV-Map." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 587, + 128, + 599 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 587, + 128, + 599 + ], + "spans": [ + { + "bbox": [ + 47, + 587, + 128, + 599 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 608, + 287, + 693 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 608, + 287, + 693 + ], + "spans": [ + { + "bbox": [ + 46, + 608, + 287, + 693 + ], + "type": "text", + "content": "High-definition maps (HD maps) play a crucial role in ensuring the safe navigation of autonomous vehicles, by providing essential positional and semantic information about road elements. Ideally, one would expect the process of constructing HD maps to be as simple as collecting numerous sensory data while driving and then utilizing an automatic algorithm to extract the road elements," + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 310, + 213, + 544, + 353 + ], + "blocks": [ + { + "bbox": [ + 310, + 213, + 544, + 353 + ], + "lines": [ + { + "bbox": [ + 310, + 213, + 544, + 353 + ], + "spans": [ + { + "bbox": [ + 310, + 213, + 544, + 353 + ], + "type": "image", + "image_path": "d6e579133b4ba25187e6ef94d00293d806862783f46e358bdcd855b6214fe12d.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 360, + 546, + 444 + ], + "lines": [ + { + "bbox": [ + 305, + 360, + 546, + 444 + ], + "spans": [ + { + "bbox": [ + 305, + 360, + 546, + 444 + ], + "type": "text", + "content": "Figure 1: Current onboard methods generate unreliable HD map predictions that are inconsistent across multiple views, due to occlusions or viewpoint changes. By contrast, our offboard pipeline constructs a unified and multi-view consistent HD map with clearer lanes. Our key design is a region-centric framework that aggregates single-frame information for each target HD map region." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 459, + 546, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 459, + 546, + 590 + ], + "spans": [ + { + "bbox": [ + 304, + 459, + 546, + 590 + ], + "type": "text", + "content": "as illustrated in Fig. 1. However, the mainstream solutions generally involve human annotators, as seen in widely-used datasets [3, 4, 8, 39]. This design is based on the consideration of the infrastructure role and high re-usability of HD maps, which can serve autonomous vehicles for virtually infinite times after a single construction process before any environmental changes. Even so, the expense of manual annotation obstructs the expansion of autonomous driving to new locations, and we aim to develop reliable algorithms that can decrease or replace the need for human labor in HD map construction." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": "Towards this goal, there have been recent attempts that automatically generate HD maps using bird's-eye-view (BEV) perception [11, 13, 15]. However, their results are often unreliable, as illustrated by noticeable inconsistencies in the predicted HD maps from different viewpoints (a representative example is in Fig. 1). We argue that multi-view consistency is an intrinsic property of HD maps, because the rigid and static HD maps shouldn't change significantly after simply switching viewpoints. The violations of consistency arise from the fact that existing BEV perception" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 702, + 126, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 126, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 126, + 712 + ], + "type": "text", + "content": "* Equal contribution." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8658" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 71, + 286, + 148 + ], + "blocks": [ + { + "bbox": [ + 53, + 71, + 286, + 148 + ], + "lines": [ + { + "bbox": [ + 53, + 71, + 286, + 148 + ], + "spans": [ + { + "bbox": [ + 53, + 71, + 286, + 148 + ], + "type": "image", + "image_path": "37ba0b646d97a46811ffa293b1afa6d51c06d8788d81fe62c60951f31aabc4b1.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 159, + 287, + 196 + ], + "lines": [ + { + "bbox": [ + 46, + 159, + 287, + 196 + ], + "spans": [ + { + "bbox": [ + 46, + 159, + 287, + 196 + ], + "type": "text", + "content": "Figure 2: Our Voxel-NeRF reconstructs high-quality 3D structure of the scene. As in the rendering result, the lanes and pedestrian crossings (highlighted) are clear." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 208, + 286, + 280 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 208, + 286, + 280 + ], + "spans": [ + { + "bbox": [ + 46, + 208, + 286, + 280 + ], + "type": "text", + "content": "algorithms do not account for all the views explicitly and thus do not align their predictions. This issue further boils down to their onboard setting, where the models are only allowed to access computing devices onboard in autonomous vehicles and can only handle a single frame or a few neighboring frames." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 281, + 286, + 448 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 281, + 286, + 448 + ], + "spans": [ + { + "bbox": [ + 46, + 281, + 286, + 448 + ], + "type": "text", + "content": "Given such limitations of the onboard setup, we underline a critical yet under-explored offboard setup that removes the computation constraints. Our offboard setting aligns well with the infrastructure role of HD maps: constructing HD maps can and should utilize powerful data centers to maximize the fidelity of predictions, thus ensuring the safety and reliability of the virtually infinite usages of HD maps. By aggregating information from diverse viewpoints and enhancing consistency, our offboard generation provides a natural improvement. As shown in Fig. 1, having multiple views of a shared region offers richer geometric and semantic cues, as well as improves the completeness of scene understanding, particularly regarding frequent occlusions in urban traffic." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 450, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 450, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 450, + 287, + 714 + ], + "type": "text", + "content": "With HD map construction primarily relying on vision information to infer the semantics, which is different from the previous offboard studies depending on point clouds, we are the first to explore a vision-oriented offboard perception framework to our best knowledge. To this end, we propose Multi-view Map (MV-Map) that leverages information from every frame's viewpoint and generates a unified HD map consistent with all of them. In contrast to the frame-centric design in current onboard methods that merges a fixed number of frames on the input level, we propose a region-centric design inspired by \"offboard 3D detection\" [30] to fully utilize the data from diverse views. Notably, our design can connect every HD map region with an arbitrary number of input frames covering its area. The pipeline of our framework involves extracting all the HD map patches predicted by an off-the-shelf onboard model related to that HD map region, and then fusing the patches into a final result that agrees with all the views, as illustrated in the arrows in Fig. 1. To give more weight to reliable frames, such as those with a clear view of the target region, we introduce an \"uncertainty network\" as a key component, which assigns confidence scores to onboard results and performs a weighted" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 305, + 72, + 523, + 84 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 523, + 84 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 523, + 84 + ], + "type": "text", + "content": "average of HD map patches guided by the confidence." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 86, + 545, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 86, + 545, + 361 + ], + "spans": [ + { + "bbox": [ + 304, + 86, + 545, + 361 + ], + "type": "text", + "content": "We further enhance the consensus among all the frames by augmenting the uncertainty network with cross-view consistency information. Our key insight is to learn a coherent 3D structure from diverse views and provide it as an auxiliary input to the uncertainty network. For this purpose, we exploit neural radiance fields (NeRFs) [22], a state-of-the-art approach that represents 3D structures of scenes. As shown in Fig. 2, our NeRF model synthesizes a high-quality scene structure. Compared with alternative 3D reconstruction strategies like structure from motion (e.g., COLMAP [34]), NeRF is more preferred from a practical perspective, because its runtime grows linearly with the frame number, whereas COLMAP increases quadratically. Moreover, NeRF is fully self-supervised and does not require additional annotations, unlike multi-view stereo methods such as MVSNet [44]. To improve the scalability of NeRF, we leverage a voxelized variant of NeRF (VoxelNeRF) to promote efficiency and propose loss functions that implicitly guide the concentration of NeRF on the near-ground geometry related to HD map generation. Additionally, we highlight NeRF's flexibility and scalability to an arbitrary number of views, making it critical in offboard HD map generation." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 361, + 531, + 373 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 361, + 531, + 373 + ], + "spans": [ + { + "bbox": [ + 317, + 361, + 531, + 373 + ], + "type": "text", + "content": "To summarize, we make the following contributions:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 375, + 545, + 483 + ], + "type": "list", + "angle": 0, + "index": 11, + "blocks": [ + { + "bbox": [ + 306, + 375, + 545, + 410 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 375, + 545, + 410 + ], + "spans": [ + { + "bbox": [ + 306, + 375, + 545, + 410 + ], + "type": "text", + "content": "1. We are the first to study the problem of learning to generate HD maps offboard, and we are also the first vision-oriented offboard study to our best knowledge." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 411, + 545, + 446 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 411, + 545, + 446 + ], + "spans": [ + { + "bbox": [ + 306, + 411, + 545, + 446 + ], + "type": "text", + "content": "2. We propose an effective region-centric framework MV-Map that can generate a multi-view consistent HD map from an arbitrarily large number of frames." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 446, + 545, + 483 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 446, + 545, + 483 + ], + "spans": [ + { + "bbox": [ + 306, + 446, + 545, + 483 + ], + "type": "text", + "content": "3. We introduce and extend Voxel-NeRF to encode the 3D structure from all frames for HD map generation tasks, further guiding the fusion for multi-view consistency." + } + ] + } + ], + "index": 10 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 305, + 483, + 545, + 532 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 483, + 545, + 532 + ], + "spans": [ + { + "bbox": [ + 305, + 483, + 545, + 532 + ], + "type": "text", + "content": "Large-scale experiments on nuScenes [3] show that MV-Map significantly improves HD map quality. Notably, MV-Map can effectively utilize an increasing number of input frames, making it attractive for real-world applications." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 545, + 392, + 558 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 545, + 392, + 558 + ], + "spans": [ + { + "bbox": [ + 306, + 545, + 392, + 558 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "type": "text", + "content": "Offboard 3D perception. The need for large-volume training data encourages developing offboard algorithms. Existing studies mainly focus on predicting 3D bounding boxes [24, 28, 30, 43]. The most representative work on \"offboard 3D detection\" [30] extracts multi-frame point clouds in object tracks and refines the 3D bounding boxes with the \"4D\" data. Its success heavily relies on the absolute 3D positions of point clouds, where simply overlaying Li-DAR points can construct denser surfaces of objects. However, in HD map generation that relies on images, it is not straightforward to accumulate imagery data in the 3D space. To overcome this limitation, we propose region-centric fu" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8659" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 109 + ], + "type": "text", + "content": "sion to aggregate multi-frame information and utilize multiview reconstruction, e.g. NeRF, to encode global geometry. Our study is also the first vision-oriented offboard pipeline." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 111, + 289, + 375 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 111, + 289, + 375 + ], + "spans": [ + { + "bbox": [ + 47, + 111, + 289, + 375 + ], + "type": "text", + "content": "BEV segmentation and HD map construction. Onboard HD map construction is closely related to BEV segmentation, as in HDMapNet [13]. The major challenge in BEV segmentation is to map the image features to the 3D world. The conventional approach leverages inverse perspective warping [1, 2, 6, 27, 31]. BEV perception methods either apply attention to capture the transformation [15, 19], incorporate depth information [12, 14, 26, 29], or directly query the features from voxels [11]. To better support downstream applications, some recent methods [16, 18] have developed special decoders to generate vectorized HD maps. Unlike these onboard methods, our proposition is a general offboard pipeline that utilizes any off-the-shelf segmentation models as an internal component and refines its results with multi-view consistent fusion. In this sense, neural map prior [41] and NeMO [47] also propose to perform long-term temporal fusion, but they primarily focus on an onboard setting and cannot fully leverage the multi-view consistency from long video sequences. Compared with them, our MV-Map is an offboard framework and explicitly accounts for the geometry of diverse views by reconstructing the 3D structure of the scene." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 378, + 289, + 606 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 378, + 289, + 606 + ], + "spans": [ + { + "bbox": [ + 47, + 378, + 289, + 606 + ], + "type": "text", + "content": "Neural radiance fields. NeRF [22] has shown outstanding capability in 3D reconstruction. Recent work [20, 32, 37, 40] has extended NeRF into large unbounded scenes, such as city-scale NeRF with ego-centric camera settings [32, 37, 40] and improvement from depth-supervised methods [5, 25, 38, 42]. With NeRF's ability to optimize 3D structures from numerous views, it becomes an ideal method to enforce multi-view consistency for offboard perception. However, as we are the first to adapt NeRF for HD map generation, some important modifications are made. First, we adopt voxel-based NeRF [10, 17, 23, 35, 36] to accelerate the NeRF training by voxelizing the space and encoding the parameters for each position in the voxels. This allows us to reconstruct a huge scene from nuScenes within minutes. In addition, we propose a \"total-variance loss\" to enhance NeRF's concentration on the near-ground geometry, which also reflects the shift of concentration from pixel quality to downstream HD map generation." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 617, + 220, + 632 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 617, + 220, + 632 + ], + "spans": [ + { + "bbox": [ + 47, + 617, + 220, + 632 + ], + "type": "text", + "content": "3. Offboard HD Map Generation" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 639, + 287, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 639, + 287, + 687 + ], + "spans": [ + { + "bbox": [ + 47, + 639, + 287, + 687 + ], + "type": "text", + "content": "Given a sequence of sensory data, the goal of HD map generation is to predict the positions and semantics of road elements in the BEV space, including road dividers, road boundaries, and pedestrian crossings." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "text", + "content": "Problem statement. We consider the input of HD map generation as " + }, + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{D} = \\{(I_i, P_i)\\}_{i=1}^N" + }, + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "inline_equation", + "content": "I_i" + }, + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "text", + "content": " denotes the " + }, + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "text", + "content": "-th" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "text", + "content": "sensor frame, " + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "inline_equation", + "content": "P_{i}" + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "text", + "content": " is the set of associated sensor poses, and " + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "text", + "content": " is the total number of frames in the database representing diverse views of a scene captured by a moving ego vehicle. The output is denoted as " + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "inline_equation", + "content": "\\mathcal{M} = \\{M_i\\}_{i=1}^N" + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "inline_equation", + "content": "M_{i}" + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "text", + "content": " is the HD map for the region nearby the ego vehicle on frame " + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "text", + "content": ". Following HDMapNet [13], we define " + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "inline_equation", + "content": "M_{i}" + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "text", + "content": " as a local semantic map on BEV. Note that the aforementioned formulation is agnostic to sensor types. In the main paper, we mainly focus on vision-oriented HD map generation, and we extend it to leveraging additional LiDAR data in Sec. 5.6. Specifically, every frame " + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "inline_equation", + "content": "I_{i}" + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "text", + "content": " contains " + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "inline_equation", + "content": "K = 6" + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "text", + "content": " RGB images " + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "inline_equation", + "content": "\\{I_{i,j}\\}_{j=1}^{K}" + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "text", + "content": " on nuScenes [3], and " + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "inline_equation", + "content": "P_{i} = \\{P_{i,j}\\}_{j=1}^{K}" + }, + { + "bbox": [ + 304, + 72, + 545, + 229 + ], + "type": "text", + "content": " comprises of the intrinsic and extrinsic matrices of corresponding cameras." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 232, + 546, + 341 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 232, + 546, + 341 + ], + "spans": [ + { + "bbox": [ + 304, + 232, + 546, + 341 + ], + "type": "text", + "content": "Offboard vs. onboard settings. Compared with the conventional onboard setup, our offboard setup offers greater flexibility in terms of speed and computation resources. Onboard HD map generation algorithms are often constrained by efficiency requirements and cannot use all the " + }, + { + "bbox": [ + 304, + 232, + 546, + 341 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 232, + 546, + 341 + ], + "type": "text", + "content": " frames in a single run. By contrast, offboard algorithms are allowed to have access to all the " + }, + { + "bbox": [ + 304, + 232, + 546, + 341 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 232, + 546, + 341 + ], + "type": "text", + "content": " frames, and can then leverage the offline setting and abundant computation resources to generate HD maps of higher quality." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 343, + 546, + 511 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 343, + 546, + 511 + ], + "spans": [ + { + "bbox": [ + 304, + 343, + 546, + 511 + ], + "type": "text", + "content": "From frame-centric to region-centric designs. There are different strategies to utilize the temporal data from " + }, + { + "bbox": [ + 304, + 343, + 546, + 511 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 343, + 546, + 511 + ], + "type": "text", + "content": " frames, similar to offboard 3D detection [30]. A direct solution is frame-centric [30], in which we naively increase the number of frames for existing onboard HD map construction methods, typically BEV segmentation models, and extend them to long sequences. While previous work [13, 15] has illustrated the benefit of longer temporal horizons, a multi-frame BEV segmentation model can only handle a fixed number of input frames, and increasing the frame number requires a linear growth in GPU capacity. Therefore, simply scaling up the input frames of existing onboard models is not an effective way of exploiting the offboard data, which often have varying and large frame numbers." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 511, + 545, + 595 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 511, + 545, + 595 + ], + "spans": [ + { + "bbox": [ + 304, + 511, + 545, + 595 + ], + "type": "text", + "content": "To overcome the limitations of the frame-centric design, we propose a novel region-centric design that adaptively aggregates information from an arbitrary number of available frames for each HD map region. Our design is inspired by the object-centric notion in 3D detection [30], but extends to the task of HD map construction. Doing so enables the consensus across frames captured from different viewpoints." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 606, + 452, + 621 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 606, + 452, + 621 + ], + "spans": [ + { + "bbox": [ + 306, + 606, + 452, + 621 + ], + "type": "text", + "content": "4. Method: Multi-view Map" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "type": "text", + "content": "Overview. Fig. 3 illustrates the overall framework of our Multi-view Map (MV-Map). An onboard HD map model processes every frame " + }, + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "type": "inline_equation", + "content": "(I_i, P_i)" + }, + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "type": "text", + "content": " and generates its corresponding BEV feature map " + }, + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "type": "inline_equation", + "content": "F_i" + }, + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "type": "text", + "content": " and HD map semantics " + }, + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "type": "inline_equation", + "content": "S_i" + }, + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "type": "text", + "content": " (Sec. 4.1). Then, an uncertainty network assesses the reliability of the single-frame information " + }, + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "type": "inline_equation", + "content": "F_i" + }, + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "type": "text", + "content": " for every region on the HD map (Sec. 4.2). Meanwhile, a voxelized NeRF" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 316, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 316, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 316, + 757 + ], + "type": "text", + "content": "8660" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 88, + 70, + 504, + 214 + ], + "blocks": [ + { + "bbox": [ + 88, + 70, + 504, + 214 + ], + "lines": [ + { + "bbox": [ + 88, + 70, + 504, + 214 + ], + "spans": [ + { + "bbox": [ + 88, + 70, + 504, + 214 + ], + "type": "image", + "image_path": "95d95c64fca981a4691a46e46e3f4e5446098ce12c95f0d9c648c73e57cf5db6.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 219, + 547, + 269 + ], + "lines": [ + { + "bbox": [ + 45, + 219, + 547, + 269 + ], + "spans": [ + { + "bbox": [ + 45, + 219, + 547, + 269 + ], + "type": "text", + "content": "Figure 3: Offboard pipeline of MV-Map. Given an arbitrary number of input frames, MV-Map first leverages an off-the-shelf onboard model to generate BEV features and semantic maps for each frame. Then an uncertainty network predicts their corresponding confidence maps and guides the region-centric aggregation of a unified HD map. Our pipeline further develops a Voxel-NeRF tailored to 3D structures related to HD maps to augment MV-Map with multi-view geometry." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 280, + 289, + 353 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 280, + 289, + 353 + ], + "spans": [ + { + "bbox": [ + 46, + 280, + 289, + 353 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{NeRF}}" + }, + { + "bbox": [ + 46, + 280, + 289, + 353 + ], + "type": "text", + "content": " optimizes a global 3D structure from all " + }, + { + "bbox": [ + 46, + 280, + 289, + 353 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 280, + 289, + 353 + ], + "type": "text", + "content": " frames and provides multi-view consistency information to the uncertainty network (Sec. 4.3). The final prediction for every region on the HD map is produced by a weighted average of the single-frame semantics " + }, + { + "bbox": [ + 46, + 280, + 289, + 353 + ], + "type": "inline_equation", + "content": "S_{i}" + }, + { + "bbox": [ + 46, + 280, + 289, + 353 + ], + "type": "text", + "content": ", which enables handling an arbitrary number of frames." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 361, + 146, + 372 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 361, + 146, + 372 + ], + "spans": [ + { + "bbox": [ + 47, + 361, + 146, + 372 + ], + "type": "text", + "content": "4.1. Onboard Model" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "spans": [ + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "text", + "content": "The onboard model is the entry point of our pipeline. Most existing HD map generation methods follow an encoder-decoder design. The encoder generates a BEV feature map " + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "inline_equation", + "content": "F_{i}" + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "text", + "content": " from the input " + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "inline_equation", + "content": "(I_i, P_i)" + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "inline_equation", + "content": "\\mathsf{Encoder}(I_i, P_i) \\to F_i" + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "text", + "content": ", and the decoder converts the feature map " + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "inline_equation", + "content": "F_{i}" + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "text", + "content": " into a semantic map " + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "inline_equation", + "content": "S_{i}" + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "inline_equation", + "content": "\\mathsf{Decoder}(F_i) \\to S_i" + }, + { + "bbox": [ + 46, + 379, + 287, + 451 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 452, + 288, + 524 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 452, + 288, + 524 + ], + "spans": [ + { + "bbox": [ + 46, + 452, + 288, + 524 + ], + "type": "text", + "content": "Since our pipeline only requires the BEV feature map " + }, + { + "bbox": [ + 46, + 452, + 288, + 524 + ], + "type": "inline_equation", + "content": "F_{i}" + }, + { + "bbox": [ + 46, + 452, + 288, + 524 + ], + "type": "text", + "content": " to activate the subsequent modules, MV-Map is agnostic to specific encoder-decoder designs. Without the loss of generality, we mainly adopt the encoder in SimpleBEV [11] and use a lightweight convolutional decoder. Results based on additional models are in Table D (Supplementary)." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "spans": [ + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "text", + "content": "Encoder. For each frame, a convolutional backbone first converts " + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "text", + "content": " images " + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "inline_equation", + "content": "\\{I_{i,j}\\}_{j = 1}^{K}" + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "text", + "content": " into 2D image feature maps " + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "inline_equation", + "content": "\\{F_{i,j}^{2\\mathrm{D}}\\}_{j = 1}^{K}" + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "text", + "content": ". The features are then lifted into the 3D world, through a set of voxels that are pre-defined by the encoder with shape " + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "inline_equation", + "content": "X\\times Y\\times Z" + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "text", + "content": " centered around the ego vehicle: the 2D features are bi-linearly sampled for every voxel based on their projected locations on the images, leading to a voxelized 3D feature map " + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "inline_equation", + "content": "F_{i}^{3\\mathrm{D}}" + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "text", + "content": ". Finally, reducing the Z-axis of " + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "inline_equation", + "content": "F_{i}^{3\\mathrm{D}}" + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "text", + "content": " produces a BEV feature map " + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "inline_equation", + "content": "F_{i}" + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "text", + "content": " with shape " + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "inline_equation", + "content": "X\\times Y\\times C" + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 47, + 526, + 288, + 647 + ], + "type": "text", + "content": " is the feature dimension." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 650, + 287, + 698 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 650, + 287, + 698 + ], + "spans": [ + { + "bbox": [ + 46, + 650, + 287, + 698 + ], + "type": "text", + "content": "Decoder. Our decoder is a fully-convolutional segmentation head that predicts the logits of semantics from every BEV grid in " + }, + { + "bbox": [ + 46, + 650, + 287, + 698 + ], + "type": "inline_equation", + "content": "F_{i}" + }, + { + "bbox": [ + 46, + 650, + 287, + 698 + ], + "type": "text", + "content": ". It generates the surrounding HD map as the semantic segmentation result " + }, + { + "bbox": [ + 46, + 650, + 287, + 698 + ], + "type": "inline_equation", + "content": "S_{i}" + }, + { + "bbox": [ + 46, + 650, + 287, + 698 + ], + "type": "text", + "content": " with shape " + }, + { + "bbox": [ + 46, + 650, + 287, + 698 + ], + "type": "inline_equation", + "content": "X \\times Y" + }, + { + "bbox": [ + 46, + 650, + 287, + 698 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 701, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 701, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 47, + 701, + 287, + 714 + ], + "type": "text", + "content": "Region-centric extension. Our region-centric design" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 280, + 545, + 340 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 280, + 545, + 340 + ], + "spans": [ + { + "bbox": [ + 304, + 280, + 545, + 340 + ], + "type": "text", + "content": "considers each BEV grid as an HD map region. If a grid is covered in " + }, + { + "bbox": [ + 304, + 280, + 545, + 340 + ], + "type": "inline_equation", + "content": "N'" + }, + { + "bbox": [ + 304, + 280, + 545, + 340 + ], + "type": "text", + "content": " frames, it receives " + }, + { + "bbox": [ + 304, + 280, + 545, + 340 + ], + "type": "inline_equation", + "content": "N'" + }, + { + "bbox": [ + 304, + 280, + 545, + 340 + ], + "type": "text", + "content": " features and predictions from different viewpoints. MV-Map then fuses information from " + }, + { + "bbox": [ + 304, + 280, + 545, + 340 + ], + "type": "inline_equation", + "content": "N'" + }, + { + "bbox": [ + 304, + 280, + 545, + 340 + ], + "type": "text", + "content": " view-specific frames to create a multi-view consistent feature for this region, detailed as below." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 345, + 539, + 358 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 345, + 539, + 358 + ], + "spans": [ + { + "bbox": [ + 305, + 345, + 539, + 358 + ], + "type": "text", + "content": "4.2. Global Aggregation via Uncertainty Network" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "text", + "content": "Region-centric uncertainty-aware fusion. Our region-centric offboard pipeline learns to aggregate the " + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "text", + "content": " frames of independent HD map predictions " + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "inline_equation", + "content": "\\{S_i\\}_{i=1}^N" + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "text", + "content": " into a multiview consistent prediction for each region. Our key design is to introduce an uncertainty network. For the HD map predictions from all viewpoints, the uncertainty network assigns a confidence score to each BEV grid, resulting in " + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "inline_equation", + "content": "N \\times X \\times Y" + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "text", + "content": " scores that reflect the pairwise reliability of a viewpoint contributing to an HD map region. Specifically, the uncertainty network takes the BEV features " + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "inline_equation", + "content": "\\{F_i\\}_{i=1}^N" + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "text", + "content": " as input and generates the confidence maps " + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "inline_equation", + "content": "\\{C_i\\}_{i=1}^N" + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "text", + "content": ", with " + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "inline_equation", + "content": "C_i" + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "text", + "content": " of shape " + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "inline_equation", + "content": "X \\times Y" + }, + { + "bbox": [ + 304, + 363, + 545, + 555 + ], + "type": "text", + "content": ". In Sec. 4.3, we will describe how we further incorporate global geometry encoded by Voxel-NeRF into the uncertainty network. The architecture of our uncertainty network is illustrated in Fig. 4, adopting a UNet-like [33] structure for predicting densely on every voxel." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 555, + 545, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 555, + 545, + 651 + ], + "spans": [ + { + "bbox": [ + 304, + 555, + 545, + 651 + ], + "type": "text", + "content": "We then aggregate the per-frame semantics and confidence into a final HD map. Suppose an arbitrary target position " + }, + { + "bbox": [ + 304, + 555, + 545, + 651 + ], + "type": "inline_equation", + "content": "(x^w, y^w)" + }, + { + "bbox": [ + 304, + 555, + 545, + 651 + ], + "type": "text", + "content": " is specified in the world coordinate system, we transform it to the local coordinate system of every frame with poses " + }, + { + "bbox": [ + 304, + 555, + 545, + 651 + ], + "type": "inline_equation", + "content": "\\{P_i\\}_{i=1}^N" + }, + { + "bbox": [ + 304, + 555, + 545, + 651 + ], + "type": "text", + "content": " and sample the semantic maps and confidence scores at corresponding locations. Finally, the prediction for " + }, + { + "bbox": [ + 304, + 555, + 545, + 651 + ], + "type": "inline_equation", + "content": "(x^w, y^w)" + }, + { + "bbox": [ + 304, + 555, + 545, + 651 + ], + "type": "text", + "content": " is obtained by a weighted average of per-frame semantics according to their confidence." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 654, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 545, + 714 + ], + "type": "text", + "content": "KL-divergence loss for enhanced uncertainty learning. In addition to generating confidence scores, we add a multi-layer perceptron (MLP) head to the uncertainty network to infer the KL-divergence between the predicted and ground truth semantics, as shown in Fig. 4. Intuitively, learning to" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "8661" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 76, + 265, + 178 + ], + "blocks": [ + { + "bbox": [ + 53, + 76, + 265, + 178 + ], + "lines": [ + { + "bbox": [ + 53, + 76, + 265, + 178 + ], + "spans": [ + { + "bbox": [ + 53, + 76, + 265, + 178 + ], + "type": "image", + "image_path": "0b30b1c42cc3b0917bbfad8d8486595a4bc29e5bba017992e56e89067004e97b.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 181, + 289, + 253 + ], + "lines": [ + { + "bbox": [ + 46, + 181, + 289, + 253 + ], + "spans": [ + { + "bbox": [ + 46, + 181, + 289, + 253 + ], + "type": "text", + "content": "Figure 4: Architecture of uncertainty network, which takes as input the feature map and the augmented 3D positions from NeRF for each voxel (Sec. 4.3). It outputs the confidence maps for region-centric fusion and, optionally, the predicted KL-divergence for the KL-divergence loss (detailed in Sec. 4.2)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 261, + 287, + 357 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 261, + 287, + 357 + ], + "spans": [ + { + "bbox": [ + 46, + 261, + 287, + 357 + ], + "type": "text", + "content": "regress the KL-divergence value between the predicted and ground truth HD maps augments the confidence score of the uncertainty network, because a smaller KL-divergence value indicates better quality of map construction and the uncertainty network should assign higher confidence accordingly. During training, we encourage the inferred divergence " + }, + { + "bbox": [ + 46, + 261, + 287, + 357 + ], + "type": "inline_equation", + "content": "\\mathrm{KL}^U" + }, + { + "bbox": [ + 46, + 261, + 287, + 357 + ], + "type": "text", + "content": " to be close to the true divergence " + }, + { + "bbox": [ + 46, + 261, + 287, + 357 + ], + "type": "inline_equation", + "content": "\\mathrm{KL}^G" + }, + { + "bbox": [ + 46, + 261, + 287, + 357 + ], + "type": "text", + "content": " between semantics " + }, + { + "bbox": [ + 46, + 261, + 287, + 357 + ], + "type": "inline_equation", + "content": "S_{i}" + }, + { + "bbox": [ + 46, + 261, + 287, + 357 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 261, + 287, + 357 + ], + "type": "inline_equation", + "content": "S_{i}" + }, + { + "bbox": [ + 46, + 261, + 287, + 357 + ], + "type": "text", + "content": "'s ground truth, formally," + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 62, + 364, + 287, + 397 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 364, + 287, + 397 + ], + "spans": [ + { + "bbox": [ + 62, + 364, + 287, + 397 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {K L}} = \\frac {1}{X Y} \\sum_ {x = 1} ^ {X} \\sum_ {y = 1} ^ {Y} \\| \\mathrm {K L} ^ {G} [ x, y ] - \\mathrm {K L} ^ {U} [ x, y ] \\| _ {2} ^ {2}. \\tag {1}", + "image_path": "ff4e1d2fcb47942b4f27461cb4a964178e02926aa1d7276c6fcc2cf2e0be52ba.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 404, + 287, + 489 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 404, + 287, + 489 + ], + "spans": [ + { + "bbox": [ + 46, + 404, + 287, + 489 + ], + "type": "text", + "content": "We train the uncertainty network with both a cross-entropy loss between the fusion result and the ground truth semantics at each location " + }, + { + "bbox": [ + 46, + 404, + 287, + 489 + ], + "type": "inline_equation", + "content": "(x^w, y^w)" + }, + { + "bbox": [ + 46, + 404, + 287, + 489 + ], + "type": "text", + "content": " [13] and our auxiliary KL-divergence loss in Eqn. 1. Given that the weighted average operation is differentiable, the gradients from both of the loss terms can be back-propagated to the confidence scores for updating the uncertainty network." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 491, + 256, + 504 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 491, + 256, + 504 + ], + "spans": [ + { + "bbox": [ + 47, + 491, + 256, + 504 + ], + "type": "text", + "content": "4.3. Voxel-NeRF for Multi-view Consistency" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 507, + 287, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 507, + 287, + 555 + ], + "spans": [ + { + "bbox": [ + 47, + 507, + 287, + 555 + ], + "type": "text", + "content": "MV-Map further leverages a voxelized NeRF to effectively construct a unified 3D structure of the scene from the " + }, + { + "bbox": [ + 47, + 507, + 287, + 555 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 47, + 507, + 287, + 555 + ], + "type": "text", + "content": " frames, which is incorporated with the uncertainty network to improve the multi-view consistency of HD maps." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "text", + "content": "Voxel-NeRF for traffic scenes. NeRF [22] represents a 3D scene as a continuous function " + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{NeRF}}:(\\mathbf{x},\\theta)\\to (\\mathbf{c},\\sigma)" + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "text", + "content": ", which maps every point " + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "text", + "content": " in the 3D space to its color " + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "inline_equation", + "content": "c" + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "text", + "content": " and density " + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "text", + "content": ", relative to the viewing direction " + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "text", + "content": ". By explicitly encoding camera projection in the neural rendering process, the learned NeRF model " + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{NeRF}}" + }, + { + "bbox": [ + 46, + 558, + 288, + 714 + ], + "type": "text", + "content": " encodes the 3D geometry of the corresponding scene from input images. Despite the success of the vanilla NeRF, applying it to autonomous driving datasets poses significant challenges, because of the unbounded nature of the scenes and the huge quantities of data involved (e.g., 850 scenes on nuScenes [3]). Therefore, we introduce a voxelized NeRF based on DVGO [36] for better training speed and scalability. Our Voxel-NeRF captures" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "type": "text", + "content": "multi-view consistent geometry for outdoor scenes, instead of small objects as in conventional NeRFs. To achieve this, we initialize voxel grids with shape " + }, + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "type": "inline_equation", + "content": "X_{s} \\times Y_{s} \\times Z_{s}" + }, + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "type": "text", + "content": " to cover the entire scene, which is larger than " + }, + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "type": "inline_equation", + "content": "X \\times Y \\times Z" + }, + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "type": "text", + "content": " used in onboard models for single-frame areas. For each camera ray, the neural rendering operation in Voxel-NeRF concurrently queries every voxel intersected by the ray. This concurrent querying of voxels significantly accelerates the training of our Voxel-NeRF, from hours to minutes for any scene in nuScenes, enabling a reasonable computation budget for MV-Map. More details can be found in Sec. 5." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "spans": [ + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "text", + "content": "Augmenting uncertainty network. Conceptually, the predicted semantics at a position is more reliable when it resides on the object surfaces. Once NeRF produces a multiview consistent structure, we can compute the distance between each voxel center and its closest surface. Such a clue can be exploited to evaluate the reliability of semantic maps. To this end, for an arbitrary " + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "inline_equation", + "content": "(x,y)" + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "text", + "content": " on BEV, we first recover all the voxel center locations at the BEV coordinate " + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "inline_equation", + "content": "(x,y)" + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{Voxel}} = \\{(x,y,z_i)\\}_{i=1}^Z" + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "text", + "content": " and then compute their corresponding pixel locations on the images " + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{Image}} = \\{(x_i^p,y_i^p)\\}_{i=1}^Z" + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "text", + "content": ". By volume rendering along the camera rays crossing these pixels, " + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{NeRF}}" + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "text", + "content": " reconstructs the 3D positions of these pixels, denoted as " + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{NeRF}} = \\{(x_i^R,y_i^R,z_i^R)\\}_{i=1}^Z" + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "text", + "content": ", which are generally the intersections between their camera rays and surfaces. (Ray casting details are in Sec. B.2 (Supplementary).) By calculating " + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "inline_equation", + "content": "\\Delta L_{\\mathrm{N/V}} = \\{(x_i^R - x,y_i^R - y,z_i^R - z_i)\\}_{i=1}^Z" + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "text", + "content": ", we assess the consistency between voxel centers and the global 3D structure. Finally, we employ an MLP upon " + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "inline_equation", + "content": "\\Delta L_{\\mathrm{N/V}}" + }, + { + "bbox": [ + 304, + 206, + 546, + 459 + ], + "type": "text", + "content": " and concatenate its output with the BEV feature, which is then used as the augmented input to the uncertainty network, which is the \"augmented 3D positions\" in Fig. 4." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 460, + 544, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 460, + 544, + 568 + ], + "spans": [ + { + "bbox": [ + 305, + 460, + 544, + 568 + ], + "type": "text", + "content": "Dedicating NeRF for HD maps with total-variance loss. Note that our objective is to facilitate HD map generation, rather than optimizing rendering quality. With the majority of HD map elements situated on the ground, we modify the NeRF to focus less on the quality of pixels in the air. To this end, we introduce a simple yet effective \"total-variance loss\" that guides the optimization of near-ground geometry implicitly. This total-variance loss " + }, + { + "bbox": [ + 305, + 460, + 544, + 568 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{TV}}" + }, + { + "bbox": [ + 305, + 460, + 544, + 568 + ], + "type": "text", + "content": " is obtained by accumulating the total-variance " + }, + { + "bbox": [ + 305, + 460, + 544, + 568 + ], + "type": "inline_equation", + "content": "\\mathrm{TV}(\\cdot)" + }, + { + "bbox": [ + 305, + 460, + 544, + 568 + ], + "type": "text", + "content": " at each BEV position:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 356, + 585, + 545, + 619 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 356, + 585, + 545, + 619 + ], + "spans": [ + { + "bbox": [ + 356, + 585, + 545, + 619 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {T V}} = - \\frac {1}{X _ {s} Y _ {s}} \\sum_ {x = 1} ^ {X _ {s}} \\sum_ {y = 1} ^ {Y _ {s}} \\operatorname {T V} (x, y). \\tag {2}", + "image_path": "b9db5030b619e20022841a6d30bb27706c193c7a05c7f78012c3fafaea0907d4.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 625, + 547, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 625, + 547, + 651 + ], + "spans": [ + { + "bbox": [ + 305, + 625, + 547, + 651 + ], + "type": "text", + "content": "Here the total-variance " + }, + { + "bbox": [ + 305, + 625, + 547, + 651 + ], + "type": "inline_equation", + "content": "\\mathrm{TV}(\\cdot)" + }, + { + "bbox": [ + 305, + 625, + 547, + 651 + ], + "type": "text", + "content": " is defined as the L2-norm of the differences of occupancies along the Z-axis, given by" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 315, + 669, + 545, + 683 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 669, + 545, + 683 + ], + "spans": [ + { + "bbox": [ + 315, + 669, + 545, + 683 + ], + "type": "interline_equation", + "content": "\\operatorname {T V} (x, y) = \\| O [ x, y, 2: Z _ {s} ] - O [ x, y, 1: Z _ {s} - 1 ] \\| _ {2}, \\tag {3}", + "image_path": "81d99a5cfa07c8c884d9e02ea5e779452eba8fa8597a17dcae835c656ea7d550.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "inline_equation", + "content": "O[x,y,z]" + }, + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "text", + "content": " represents the density of voxel " + }, + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "inline_equation", + "content": "(x,y,z)" + }, + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "text", + "content": " predicted by NeRF and " + }, + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\| \\cdot \\|_2" + }, + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "text", + "content": " denotes the L2-norm." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8662" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 123, + 110, + 470, + 225 + ], + "blocks": [ + { + "bbox": [ + 46, + 70, + 547, + 108 + ], + "lines": [ + { + "bbox": [ + 46, + 70, + 547, + 108 + ], + "spans": [ + { + "bbox": [ + 46, + 70, + 547, + 108 + ], + "type": "text", + "content": "Table 1: Comparison with state-of-the-art vision-based HD map generation methods on nuScenes [3]. “*” means the results reported in HDMapNet [13]. “Average Fusion” is an offboard baseline explained in Sec. 5.2. The quantitative results indicate that our MV-Map has significant benefits to HD map generation and outperforms offboard baseline approaches." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 123, + 110, + 470, + 225 + ], + "lines": [ + { + "bbox": [ + 123, + 110, + 470, + 225 + ], + "spans": [ + { + "bbox": [ + 123, + 110, + 470, + 225 + ], + "type": "table", + "html": "
SetupMethodmIoU (Short-range / Long-range)
DividerPed CrossingBoundaryAll
OnboardIPM(B)*25.5 / -12.1 / -27.1 / -21.6 / -
IPM(B+C)*38.6 / -19.3 / -39.3 / -32.4 / -
VPN*36.5 / -15.8 / -35.6 / -29.3 / -
Lift-Splat-Shoot [29]*38.3 / -14.9 / -39.3 / -30.8 / -
HMapNet [13]40.6 / 33.918.7 / 19.439.5 / 34.932.9 / 29.4
Onboard Model (Ours)46.4 / 39.329.7 / 26.448.1 / 39.141.4 / 35.0
OffboardAverage Fusion48.86 / 42.8331.55 / 24.7551.98 / 43.9144.13 / 37.16
MV-Map (Ours)50.87 / 48.1534.52 / 33.3455.64 / 50.2847.01 / 43.92
", + "image_path": "b52e6d48935f145a5619ccd3b852eed03f5e4a483c6021deb33864189440dcb0.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 234, + 288, + 307 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 234, + 288, + 307 + ], + "spans": [ + { + "bbox": [ + 46, + 234, + 288, + 307 + ], + "type": "text", + "content": "We emphasize the \"negative\" sign in Eqn. 2. It indicates \"maximizing\" the variance, because an accurate ground plane has a peak distribution of voxel occupancy on the Z-axis instead of a uniform one. TV-loss enables Voxel-NeRF to assign larger densities to the ground plane than transient objects, leading to high-quality 3D structures as in Fig. 2." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 318, + 178, + 331 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 318, + 178, + 331 + ], + "spans": [ + { + "bbox": [ + 47, + 318, + 178, + 331 + ], + "type": "text", + "content": "4.4. Training and Inference" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 336, + 287, + 397 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 336, + 287, + 397 + ], + "spans": [ + { + "bbox": [ + 46, + 336, + 287, + 397 + ], + "type": "text", + "content": "The procedure of our offboard pipeline follows three steps: (1) we adopt an existing onboard model, (2) train Voxel-NeRF on sequences, and (3) train and infer the uncertainty network. We describe these steps in order and leave detailed configurations in Sec. G (Supplementary)." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 401, + 288, + 451 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 401, + 288, + 451 + ], + "spans": [ + { + "bbox": [ + 46, + 401, + 288, + 451 + ], + "type": "text", + "content": "Onboard model. As MV-Map is agnostic to the choice of onboard models (Sec. 4.1), here we adopt an off-the-shelf BEV segmentation model and freeze its parameters during both training and inference stages of the offboard pipeline." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 454, + 287, + 515 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 454, + 287, + 515 + ], + "spans": [ + { + "bbox": [ + 46, + 454, + 287, + 515 + ], + "type": "text", + "content": "Voxel-NeRF. We train the Voxel-NeRF for all sequences in our training and validation datasets, using both conventional photometric loss and our total-variance loss (Sec. 4.3). Note that our NeRF training is entirely self-supervised and does not require any annotations." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 520, + 287, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 520, + 287, + 616 + ], + "spans": [ + { + "bbox": [ + 46, + 520, + 287, + 616 + ], + "type": "text", + "content": "Uncertainty network. The region-centric design enables the uncertainty network to handle varying frame numbers of offboard data. In practice, however, the GPU capacities and batching during training limit the network to a fixed and restricted frame number. To overcome this issue, we adopt the solution from video-based tasks (e.g., 2D multi-object tracking [21, 46]), where models are trained on short video clips but are inferred iteratively on unbounded sequences." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 618, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 618, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 618, + 288, + 715 + ], + "type": "text", + "content": "Similarly, given the input " + }, + { + "bbox": [ + 46, + 618, + 288, + 715 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 618, + 288, + 715 + ], + "type": "text", + "content": " frames of a scene, the uncertainty network is trained with samples containing " + }, + { + "bbox": [ + 46, + 618, + 288, + 715 + ], + "type": "inline_equation", + "content": "M(M < N)" + }, + { + "bbox": [ + 46, + 618, + 288, + 715 + ], + "type": "text", + "content": " adjacent frames to fit into limited GPU memory. The loss is a weighted sum of our KL-divergence loss and a BEV segmentation loss (Sec. 4.2). During inference, we apply the uncertainty network to all the " + }, + { + "bbox": [ + 46, + 618, + 288, + 715 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 618, + 288, + 715 + ], + "type": "text", + "content": " frames independently and use region-centric aggregation to fuse single-frame semantics into a unified HD map." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 233, + 388, + 246 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 233, + 388, + 246 + ], + "spans": [ + { + "bbox": [ + 306, + 233, + 388, + 246 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 250, + 497, + 262 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 250, + 497, + 262 + ], + "spans": [ + { + "bbox": [ + 306, + 250, + 497, + 262 + ], + "type": "text", + "content": "5.1. Dataset and Implementation Details" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 268, + 545, + 329 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 268, + 545, + 329 + ], + "spans": [ + { + "bbox": [ + 304, + 268, + 545, + 329 + ], + "type": "text", + "content": "Dataset. We conduct experiments on a large-scale autonomous driving dataset: nuScenes [3]. It contains 850 videos with 28,130 and 6,019 frames for training and validation, respectively. On each timestamp, six surrounding cameras collect high-resolution images as input." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 331, + 546, + 451 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 331, + 546, + 451 + ], + "spans": [ + { + "bbox": [ + 304, + 331, + 546, + 451 + ], + "type": "text", + "content": "Evaluation metrics. Following prior work [13], we compute the intersection-over-union (IoU) for HD map categories: divider, pedestrian crossing, and road boundaries. To highlight the challenge of predicting a scene-scale HD map, our evaluation adopts both a short-range setting [13] covering " + }, + { + "bbox": [ + 304, + 331, + 546, + 451 + ], + "type": "inline_equation", + "content": "60\\mathrm{m} \\times 30\\mathrm{m}" + }, + { + "bbox": [ + 304, + 331, + 546, + 451 + ], + "type": "text", + "content": " and a new long-range setting covering " + }, + { + "bbox": [ + 304, + 331, + 546, + 451 + ], + "type": "inline_equation", + "content": "100\\mathrm{m} \\times 100\\mathrm{m}" + }, + { + "bbox": [ + 304, + 331, + 546, + 451 + ], + "type": "text", + "content": ", which aligns with the common perception range in self-driving [7, 9]. Without further mentioning, we conduct our ablation studies under the more challenging long-range setting." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "spans": [ + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "text", + "content": "Implementation details. We follow the training and inference settings in Sec. 4.4 and discuss the details in Sec. G (Supplementary). We emphasize that MV-Map is scalable to large volumes of offboard data. Within 15 minutes on a single A40 GPU, our Voxel-NeRF can optimize the 3D structure from each nuScenes sequence, which typically has over 1k images covering regions with an average length of " + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "inline_equation", + "content": "\\sim 300\\mathrm{m}" + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "text", + "content": ", less than 1 second per frame. In comparison, the common multi-view stereo baseline of COLMAP [34] may take several hours or even days. Notably, this is because COLMAP spent most of the time in feature matching, which is pairwise across frames and " + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "inline_equation", + "content": "\\mathcal{O}(N^2)" + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "text", + "content": " regarding the frame number " + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "text", + "content": ". In comparison, the time complexity of NeRF is " + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "inline_equation", + "content": "\\mathcal{O}(N)" + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "text", + "content": ". Moreover, our uncertainty network is trained on the samples with " + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "inline_equation", + "content": "M = 5" + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "text", + "content": " adjacent frames to fit into our GPU memory, but it can jointly handle all the frames (" + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "inline_equation", + "content": "\\sim 40" + }, + { + "bbox": [ + 304, + 453, + 546, + 669 + ], + "type": "text", + "content": ") in a nuScenes sequence during the inference stage, as explained in Sec. 4.4." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 673, + 531, + 686 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 673, + 531, + 686 + ], + "spans": [ + { + "bbox": [ + 306, + 673, + 531, + 686 + ], + "type": "text", + "content": "5.2. Comparison with State-of-the-Art Methods" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 689, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 714 + ], + "type": "text", + "content": "As our work represents the first study on offboard HD map generation, there are no readily available competing" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8663" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 66, + 146, + 266, + 232 + ], + "blocks": [ + { + "bbox": [ + 46, + 70, + 288, + 142 + ], + "lines": [ + { + "bbox": [ + 46, + 70, + 288, + 142 + ], + "spans": [ + { + "bbox": [ + 46, + 70, + 288, + 142 + ], + "type": "text", + "content": "Table 2: MV-Map significantly improves vectorized HD map quality over both the onboard VectorMapNet [18] model and the recent temporal fusion method Neural Map Prior [41] (NMP). " + }, + { + "bbox": [ + 46, + 70, + 288, + 142 + ], + "type": "inline_equation", + "content": "(\\dagger" + }, + { + "bbox": [ + 46, + 70, + 288, + 142 + ], + "type": "text", + "content": " means the performance reported in NMP; " + }, + { + "bbox": [ + 46, + 70, + 288, + 142 + ], + "type": "inline_equation", + "content": "\\ddagger" + }, + { + "bbox": [ + 46, + 70, + 288, + 142 + ], + "type": "text", + "content": " means the performance from VectorMapNet's officially released checkpoint.)" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 66, + 146, + 266, + 232 + ], + "lines": [ + { + "bbox": [ + 66, + 146, + 266, + 232 + ], + "spans": [ + { + "bbox": [ + 66, + 146, + 266, + 232 + ], + "type": "table", + "html": "
MethodsmAP
DividerPed CrossingBoundaryAll
VectorMapNet†47.336.139.340.9
+NMP49.642.941.944.8
ΔmAP+2.3+6.8+2.6+3.9
VectorMapNet‡47.739.838.942.1
+MV-Map55.046.245.548.9
Δ mAP+7.3+6.4+6.6+6.7
", + "image_path": "24eae29a54f63f3a2c8bc4a4aae1e805c07db84ba1161c89adffbe719c61db92.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 236, + 287, + 284 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 236, + 287, + 284 + ], + "spans": [ + { + "bbox": [ + 46, + 236, + 287, + 284 + ], + "type": "text", + "content": "methods. Additionally, our MV-Map can utilize any off-the-shelf onboard model as its internal component. To ensure a meaningful and fair comparison, we organize the experimental results and analysis in Table 1 as follows." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 285, + 287, + 464 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 285, + 287, + 464 + ], + "spans": [ + { + "bbox": [ + 46, + 285, + 287, + 464 + ], + "type": "text", + "content": "First, our onboard model adopts the simple-yet-effective design from SimpleBEV [11]. As shown in the \" onboard\" rows, our onboard model already consistently outperforms previous baselines in both short-range and long-range settings. Second, our MV-Map brings a significant improvement of " + }, + { + "bbox": [ + 46, + 285, + 287, + 464 + ], + "type": "inline_equation", + "content": "\\sim 7\\%" + }, + { + "bbox": [ + 46, + 285, + 287, + 464 + ], + "type": "text", + "content": " mIoU compared with our already effective onboard model. Notably, our offboard method is better than HDMapNet [13] by around " + }, + { + "bbox": [ + 46, + 285, + 287, + 464 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 46, + 285, + 287, + 464 + ], + "type": "text", + "content": " with over " + }, + { + "bbox": [ + 46, + 285, + 287, + 464 + ], + "type": "inline_equation", + "content": "15\\%" + }, + { + "bbox": [ + 46, + 285, + 287, + 464 + ], + "type": "text", + "content": " IoU increase on all the categories. Finally, we develop an offboard baseline algorithm called \"Average Fusion.\" It does not consider the quality of different viewpoints and performs region-centric aggregation by equally averaging the single-frame semantic maps. Compared with \"Average fusion,\" our MV-Map still improves the HD map quality by a large margin of over " + }, + { + "bbox": [ + 46, + 285, + 287, + 464 + ], + "type": "inline_equation", + "content": "\\sim 7\\%" + }, + { + "bbox": [ + 46, + 285, + 287, + 464 + ], + "type": "text", + "content": " mIoU under the long-range setting." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 468, + 243, + 480 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 468, + 243, + 480 + ], + "spans": [ + { + "bbox": [ + 47, + 468, + 243, + 480 + ], + "type": "text", + "content": "5.3. Comparison on Vectorized HD Maps" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 483, + 287, + 685 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 483, + 287, + 685 + ], + "spans": [ + { + "bbox": [ + 46, + 483, + 287, + 685 + ], + "type": "text", + "content": "We further extend our MV-Map to vectorized HD map generation to demonstrate its wide compatibility. In Table 2, we apply MV-Map to VectorMapNet [18], one of the state-of-the-art onboard models generating vectorized HD maps. Specifically, our MV-Map performs uncertainty-aware fusion on the frozen BEV features of an open-sourced VectorMapNet model. The results show that MV-Map improves the HD Map generation quality by a large margin of over " + }, + { + "bbox": [ + 46, + 483, + 287, + 685 + ], + "type": "inline_equation", + "content": "\\sim 7" + }, + { + "bbox": [ + 46, + 483, + 287, + 685 + ], + "type": "text", + "content": " mAP, proving its effectiveness in constructing high-quality HD maps. We further compare MV-Map with the recent neural map prior (NMP) [41], which also capitalizes long-term temporal fusion for global HD map generation in Table 2. In the experiments, We adopt the same metric (mAP) as VectorMapNet [18]. As clearly illustrated, our offboard MV-Map pipeline is better in both absolute (48.9 mAP vs. 44.8 mAP) and relative improvements (6.8 mAP vs. 3.9 mAP)." + } + ] + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 310, + 134, + 544, + 225 + ], + "blocks": [ + { + "bbox": [ + 304, + 70, + 545, + 130 + ], + "lines": [ + { + "bbox": [ + 304, + 70, + 545, + 130 + ], + "spans": [ + { + "bbox": [ + 304, + 70, + 545, + 130 + ], + "type": "text", + "content": "Table 3: The components in MV-Map effectively improve HD map generation step by step. We analyze the uncertainty network (UN) and KL-divergence loss " + }, + { + "bbox": [ + 304, + 70, + 545, + 130 + ], + "type": "inline_equation", + "content": "(\\mathcal{L}_{\\mathrm{KL}})" + }, + { + "bbox": [ + 304, + 70, + 545, + 130 + ], + "type": "text", + "content": " discussed in Sec. 4.2, and Voxel-NeRF (NeRF) and totalvariance loss " + }, + { + "bbox": [ + 304, + 70, + 545, + 130 + ], + "type": "inline_equation", + "content": "(\\mathcal{L}_{\\mathrm{TV}})" + }, + { + "bbox": [ + 304, + 70, + 545, + 130 + ], + "type": "text", + "content": " discussed in Sec. 4.3." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 310, + 134, + 544, + 225 + ], + "lines": [ + { + "bbox": [ + 310, + 134, + 544, + 225 + ], + "spans": [ + { + "bbox": [ + 310, + 134, + 544, + 225 + ], + "type": "table", + "html": "
IDOffboard ComponentmIoU
UN\\( \\mathcal{L}_{\\text{KL}} \\)NeRF\\( \\mathcal{L}_{\\text{TV}} \\)DividerCrossingBoundaryAll
1Onboard Model39.3026.4439.1034.95
2Average fusion42.8324.7543.9137.16
3✓46.9030.3049.0742.09
4✓✓47.3831.1149.5342.67
5✓✓✓47.6432.3649.6743.22
6✓✓✓48.0132.6550.1243.59
7✓✓✓✓48.1533.3450.2843.92
", + "image_path": "aeff25dfcfe46748f80cd6fd3eac9f608a748a46e5ae9bf1a78e430081f1ac9a.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 243, + 406, + 255 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 243, + 406, + 255 + ], + "spans": [ + { + "bbox": [ + 306, + 243, + 406, + 255 + ], + "type": "text", + "content": "5.4. Ablation Studies" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 266, + 545, + 566 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 266, + 545, + 566 + ], + "spans": [ + { + "bbox": [ + 304, + 266, + 545, + 566 + ], + "type": "text", + "content": "MV-Map Components. We quantify the improvement from each offboard module in Table 3. (1) Region-centric fusion baseline. Beginning from the onboard model (row 1), we first apply average fusion (row 2) to it (discussed in Sec. 5.2) as a baseline. The improvement indicates that our region-centric design indeed helps by fusing numerous frames into a unified HD map. (2) Uncertainty network. Replacing the average fusion (row 2) with the uncertainty network (row 3) enables larger contributions from more reliable frames and the " + }, + { + "bbox": [ + 304, + 266, + 545, + 566 + ], + "type": "inline_equation", + "content": "\\sim 5\\%" + }, + { + "bbox": [ + 304, + 266, + 545, + 566 + ], + "type": "text", + "content": " increase in mIoU validates that assessing quality is critical for better HD map quality. (3) KL-divergence loss. The " + }, + { + "bbox": [ + 304, + 266, + 545, + 566 + ], + "type": "inline_equation", + "content": "\\sim 0.5\\%" + }, + { + "bbox": [ + 304, + 266, + 545, + 566 + ], + "type": "text", + "content": " mIoU on using KL-divergence loss or not (row 3 and row 4) supports that explicitly supervising the uncertainty network with KL-divergence effectively improves the region-centric fusion to rely on frames with higher quality. (4) Voxel-NeRF. Adding NeRF to a full-fledged uncertainty network further improves the mIoU (row 4 and row 5). In the category-level analysis, we highlight that NeRF is critical for the fusion especially on the challenging structures with smaller regions, e.g., pedestrian crossings. This evidence validates the importance of global geometry in multi-view consistency. (5) Total-variance loss. Utilizing it further boosts the performance in all the scenarios, validating our effort to dedicate NeRFs for the downstream HD map generation." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "type": "text", + "content": "Scaling to more frames. We demonstrate that our fusion strategy can handle and significantly benefit from a larger number of frames, which is critical for offboard HD map generation. We evaluate our offboard framework under varied input frames in Fig. 5. MV-Map can utilize all the keyframes (40 frames) in nuScenes and this number is only bounded by the sequence length. As clearly shown in the blue curve of Fig. 5, MV-Map benefits from more frames, indicating its scalability for offboard scenarios, especially compared with the average fusion baseline, whose performance drops after using more than 15 frames. This indicates that our region-centric fusion strategy is able to" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 46, + 693, + 287, + 715 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 693, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 693, + 287, + 715 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 46, + 693, + 287, + 715 + ], + "type": "text", + "content": "NMP is not included for semantic HD map comparison in Sec. 5.2 because it adopts a different resolution for rasterized HD maps." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8664" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 66, + 72, + 270, + 210 + ], + "blocks": [ + { + "bbox": [ + 66, + 72, + 270, + 210 + ], + "lines": [ + { + "bbox": [ + 66, + 72, + 270, + 210 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 270, + 210 + ], + "type": "image", + "image_path": "f8ccfd58057f755d85868db82752e779100ba64f07cbe7c9d987cc9512a8beee.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 210, + 287, + 258 + ], + "lines": [ + { + "bbox": [ + 46, + 210, + 287, + 258 + ], + "spans": [ + { + "bbox": [ + 46, + 210, + 287, + 258 + ], + "type": "text", + "content": "Figure 5: Our MV-Map can significantly benefit from more input frames, which is attractive for offboard applications. Notably, the performance of the \"average fusion\" baseline saturates and even decreases with more input frames." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 51, + 259, + 284, + 440 + ], + "blocks": [ + { + "bbox": [ + 51, + 259, + 284, + 440 + ], + "lines": [ + { + "bbox": [ + 51, + 259, + 284, + 440 + ], + "spans": [ + { + "bbox": [ + 51, + 259, + 284, + 440 + ], + "type": "image", + "image_path": "c4885b7a41cc4c5b87b1b581e9334bd2b9af6ec538b2cc2bd412a16176c6b361.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 453, + 287, + 489 + ], + "lines": [ + { + "bbox": [ + 46, + 453, + 287, + 489 + ], + "spans": [ + { + "bbox": [ + 46, + 453, + 287, + 489 + ], + "type": "text", + "content": "Figure 6: Qualitative comparison in the long-range settings. HD map generated offboard has significantly better quality by fixing the artifacts of the onboard model." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 502, + 287, + 526 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 502, + 287, + 526 + ], + "spans": [ + { + "bbox": [ + 46, + 502, + 287, + 526 + ], + "type": "text", + "content": "reason the complementary regions among the frames, instead of blindly averaging them all." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 529, + 287, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 529, + 287, + 601 + ], + "spans": [ + { + "bbox": [ + 46, + 529, + 287, + 601 + ], + "type": "text", + "content": "Qualitative comparison. We visualize the generated HD maps in Fig. 6. As clearly shown, MV-Map corrects the artifacts from onboard models and achieves better completeness and details. In addition, the HD maps generated offboard have high fidelity compared with the ground truth, especially in the center regions covered by more frames." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "content": "Analyzing KL-divergence and confidence scores. We empirically analyze the output of the uncertainty network in Fig. 7. As for the confidence scores, we observe that they indeed decrease the contributions of unreliable regions, such as the part with occlusion in Fig. 7a, highlighted with solid circles. The invisible area has much smaller confidence than its nearby regions. Additionally, we transfer the KL-divergence prediction head to the validation set and find the predictions reasonably correlate with the confidence scores," + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 310, + 72, + 544, + 225 + ], + "blocks": [ + { + "bbox": [ + 310, + 72, + 544, + 225 + ], + "lines": [ + { + "bbox": [ + 310, + 72, + 544, + 225 + ], + "spans": [ + { + "bbox": [ + 310, + 72, + 544, + 225 + ], + "type": "image", + "image_path": "cb82f8c971dc62d190b3c944ba60267ae396f7b132aa1fd0aeb6aa10d9e4acfe.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 236, + 545, + 369 + ], + "lines": [ + { + "bbox": [ + 304, + 236, + 545, + 369 + ], + "spans": [ + { + "bbox": [ + 304, + 236, + 545, + 369 + ], + "type": "text", + "content": "Figure 7: (a) The confidence scores predicted by the uncertainty network capture the challenging regions (solid circles) as the occluded region has significantly smaller confidence values than its nearby regions. Darker colors indicate smaller confidence values. (b) Predicted KL divergence between the prediction and ground truth label captures the connection with the predicted confidence scores (dashed circles). The region with a dashed circle has a much larger predicted KL-divergence value than its nearby regions. Accordingly, this area exhibits smaller confidence scores. Darker colors mean smaller KL-divergence values." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 380, + 545, + 416 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 380, + 545, + 416 + ], + "spans": [ + { + "bbox": [ + 304, + 380, + 545, + 416 + ], + "type": "text", + "content": "as in Fig. 7b. We notice that the regions with higher KL-divergence values (Fig. 7b) also have lower confidences (Fig. 7a), highlighted with the dashed circles." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 420, + 545, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 420, + 545, + 647 + ], + "spans": [ + { + "bbox": [ + 304, + 420, + 545, + 647 + ], + "type": "text", + "content": "Using geometric information from data-driven priors. Our Voxel-NeRF offers geometric information in a fully self-supervised manner. Meanwhile, our MV-Map framework is general and can leverage alternative approaches for providing geometric information, such as learning data-driven priors from large-scale datasets. We investigate this type of approach here and consider representative monocular depth estimators that are learned off-the-shelf in a supervised manner. Specifically, we replace the rendering process of Voxel-NeRF with the results from NeWCRFs [45] (details in Sec. G, Supplementary). As in Table 4, monocular depth can improve the uncertainty fusion as well (row 2 and row 3). We further notice that NeRF performs slightly better because it encodes multiple views consistently in a shared 3D structure, while monocular depth considers each view independently and suffers from scale variation across frames. Encouraged by the benefits of these two distinct types of geometric information, future work is to combine NeRF with learnable priors into our framework." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 658, + 521, + 671 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 658, + 521, + 671 + ], + "spans": [ + { + "bbox": [ + 305, + 658, + 521, + 671 + ], + "type": "text", + "content": "5.5. Globally Consistent HD Map Generation" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "content": "Our offboard MV-Map can handle numerous frames. Its application is to expand the range of HD map generation from a local region around the ego-vehicle to a global re" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8665" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 100, + 71, + 492, + 210 + ], + "blocks": [ + { + "bbox": [ + 100, + 71, + 492, + 210 + ], + "lines": [ + { + "bbox": [ + 100, + 71, + 492, + 210 + ], + "spans": [ + { + "bbox": [ + 100, + 71, + 492, + 210 + ], + "type": "image", + "image_path": "55429bb0e6b5838c37e918a69ecaf9b7f40fe7327e076b975cb4ce9c85958b86.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 218, + 546, + 243 + ], + "lines": [ + { + "bbox": [ + 46, + 218, + 546, + 243 + ], + "spans": [ + { + "bbox": [ + 46, + 218, + 546, + 243 + ], + "type": "text", + "content": "Figure 8: Visualization of a unified, scene-scale HD map through our MV-Map. It can fuse numerous frames and generate global-scale HD maps with high quality. It is also robust under different weather conditions and complex road topology." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 49, + 329, + 285, + 399 + ], + "blocks": [ + { + "bbox": [ + 46, + 253, + 287, + 326 + ], + "lines": [ + { + "bbox": [ + 46, + 253, + 287, + 326 + ], + "spans": [ + { + "bbox": [ + 46, + 253, + 287, + 326 + ], + "type": "text", + "content": "Table 4: MV-Map is a general framework: In addition to NeRF, MV-Map can benefit from data-driven priors of geometric information; here we use monocular depth estimation [45] as an example. \"UN-Only:\" using the uncertainty network without augmentation of 3D structural information. Then we separately incorporate mono-depth or NeRF to it." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 49, + 329, + 285, + 399 + ], + "lines": [ + { + "bbox": [ + 49, + 329, + 285, + 399 + ], + "spans": [ + { + "bbox": [ + 49, + 329, + 285, + 399 + ], + "type": "table", + "html": "
MethodsmIoU
DividerPed CrossingBoundaryAll
Average Fusion42.8324.7543.9137.16
MV-Map (UN-Only)47.3831.1149.5342.67
MV-Map (Mono-Depth)48.0432.9650.0843.69
MV-Map (NeRF)48.1533.3450.2843.92
", + "image_path": "c1496fa20e64101c0d3615fd6888ee060962fa684c81caca2fcaa7bf32fdaec0.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_body" + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 51, + 471, + 282, + 529 + ], + "blocks": [ + { + "bbox": [ + 46, + 407, + 287, + 467 + ], + "lines": [ + { + "bbox": [ + 46, + 407, + 287, + 467 + ], + "spans": [ + { + "bbox": [ + 46, + 407, + 287, + 467 + ], + "type": "text", + "content": "Table 5: Performance of incorporating the LiDAR modality in MV-Map, evaluated under the long-range setting on the validation set. As a general framework, MV-Map can exploit multi-modality as input and improve the performance consistently and significantly." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 51, + 471, + 282, + 529 + ], + "lines": [ + { + "bbox": [ + 51, + 471, + 282, + 529 + ], + "spans": [ + { + "bbox": [ + 51, + 471, + 282, + 529 + ], + "type": "table", + "html": "
MethodsmIoU (Long-range)
DividerPed CrossingBoundaryAll
Onboard41.6327.1341.6536.80
MV-Map50.7232.9954.6346.11
", + "image_path": "addba26e036399e1a23647aba3d4ac1b5e4ab4b52f2034aeeb3bd6a3476736ed.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 539, + 287, + 624 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 539, + 287, + 624 + ], + "spans": [ + { + "bbox": [ + 46, + 539, + 287, + 624 + ], + "type": "text", + "content": "gion covering all the input frames, which saves the labor in stitching multiple local predictions in the real world. Our global maps in Fig. 8 demonstrate high fidelity for complex topology in two challenging scenes. While some regions do not match the ground truth, we argue that these regions fall outside the collected frames and perception ranges, which are beyond the scope of offboard algorithms." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 634, + 263, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 634, + 263, + 647 + ], + "spans": [ + { + "bbox": [ + 47, + 634, + 263, + 647 + ], + "type": "text", + "content": "5.6. Generalizability of MV-Map with LiDAR" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "type": "text", + "content": "To demonstrate the generalizability of our framework, we analyze incorporating the LiDAR sensor into MV-Map. In the main paper, we focused on cameras, because they contribute primarily to HD map generation as shown in HDMapNet [13]. On the other hand, LiDARs are also" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 255, + 546, + 316 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 255, + 546, + 316 + ], + "spans": [ + { + "bbox": [ + 304, + 255, + 546, + 316 + ], + "type": "text", + "content": "widely used for their accurate distance sensing and their ability to enhance localization, which motivates our investigation here. We first describe the design of utilizing the extra LiDAR modality and then analyze the results. Extra details are explained in Sec. C (Supplementary)." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 320, + 378, + 332 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 320, + 378, + 332 + ], + "spans": [ + { + "bbox": [ + 306, + 320, + 378, + 332 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 335, + 546, + 538 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 335, + 546, + 538 + ], + "spans": [ + { + "bbox": [ + 304, + 335, + 546, + 538 + ], + "type": "text", + "content": "Regarding the infrastructure role of HD maps, we propose a novel offboard HD map generation setup to address the unreliability of onboard BEV perception. By removing the computation constraints, the models are allowed to reason all the frames altogether and construct multi-view consistent HD maps. Concretely, we propose an offboard HD map generation framework called MV-Map. To address numerous frames, MV-Map designs region-centric aggregation to unify the HD maps from all the frames. The key design is an uncertainty network that weighs the contribution of different frames and utilizes a Voxel-NeRF to provide multi-view consistent 3D structural information. Experiments validate that MV-Map is scalable to large volumes of offboard data and significantly improves the HD map quality. We hope that our framework can become an effective augmentor for onboard algorithms and also inspire future research on offboard problems." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 540, + 546, + 636 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 540, + 546, + 636 + ], + "spans": [ + { + "bbox": [ + 304, + 540, + 546, + 636 + ], + "type": "text", + "content": "Limitations and future work. Although our Voxel-NeRF improves the offboard pipeline in a scalable way, several challenges still present, including moving objects in traffic scenes and exploiting data-driven priors for better geometric information. In addition, we seek to connect our work with auto-labeling and compare it with human annotation quality, so as to explore more potential applications such as autonomous vehicle navigation and urban planning." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 636, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 636, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 636, + 547, + 714 + ], + "type": "text", + "content": "Acknowledgement. This work was supported in part by NSF Grant 2106825, NIFA Award 2020-67021-32799, the Jump ARCHES endowment, the NCSA Fellows program, the Illinois-Inspers Partnership, and the Amazon Research Award. This work used NVIDIA GPUs at NCSA Delta through allocations CIS220014 and CIS230012 from the ACCESS program." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8666" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 53, + 91, + 286, + 113 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 286, + 113 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 286, + 113 + ], + "type": "text", + "content": "[1] Mohamed Aly. Real time detection of lane markers in urban streets. In IEEE Intelligent Vehicles Symposium, 2008. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 114, + 287, + 146 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 114, + 287, + 146 + ], + "spans": [ + { + "bbox": [ + 53, + 114, + 287, + 146 + ], + "type": "text", + "content": "[2] Massimo Bertozzi and Alberto Broggi. Real-time lane and obstacle detection on the GOLD system. In IEEE Intelligent Vehicles Symposium, 1996. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 148, + 287, + 201 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 148, + 287, + 201 + ], + "spans": [ + { + "bbox": [ + 53, + 148, + 287, + 201 + ], + "type": "text", + "content": "[3] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuScenes: A multimodal dataset for autonomous driving. In CVPR, 2020. 1, 2, 3, 5, 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 202, + 287, + 256 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 202, + 287, + 256 + ], + "spans": [ + { + "bbox": [ + 53, + 202, + 287, + 256 + ], + "type": "text", + "content": "[4] Ming-Fang Chang, John W Lambert, Patsorn Sangkloy, Jagjeet Singh, Slawomir Bak, Andrew Hartnett, De Wang, Peter Carr, Simon Lucey, Deva Ramanan, and James Hays. Argo-verse: 3D tracking and forecasting with rich maps. In CVPR, 2019. 1" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 258, + 287, + 290 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 258, + 287, + 290 + ], + "spans": [ + { + "bbox": [ + 53, + 258, + 287, + 290 + ], + "type": "text", + "content": "[5] Kangle Deng, Andrew Liu, Jun-Yan Zhu, and Deva Ramanan. Depth-supervised NeRF: Fewer views and faster training for free. In CVPR, 2022. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 292, + 287, + 334 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 292, + 287, + 334 + ], + "spans": [ + { + "bbox": [ + 53, + 292, + 287, + 334 + ], + "type": "text", + "content": "[6] Liuuyuan Deng, Ming Yang, Hao Li, Tianyi Li, Bing Hu, and Chunxiang Wang. Restricted deformable convolution-based road scene semantic segmentation using surround view cameras. In ITSC, 2020. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 335, + 287, + 390 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 335, + 287, + 390 + ], + "spans": [ + { + "bbox": [ + 53, + 335, + 287, + 390 + ], + "type": "text", + "content": "[7] Hao Dong, Xianjing Zhang, Xuan Jiang, Jun Zhang, Jintao Xu, Rui Ai, Weihao Gu, Huimin Lu, Juho Kannala, and Xieyuanli Chen. SuperFusion: Multilevel LiDAR-camera fusion for long-range HD map generation and prediction. arXiv preprint arXiv:2211.15656, 2022. 6" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 392, + 287, + 468 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 392, + 287, + 468 + ], + "spans": [ + { + "bbox": [ + 53, + 392, + 287, + 468 + ], + "type": "text", + "content": "[8] Scott Ettinger, Shuyang Cheng, Benjamin Caine, Chenxi Liu, Hang Zhao, Sabeek Pradhan, Yuning Chai, Ben Sapp, Charles R. Qi, Yin Zhou, Zoey Yang, Aur'elien Chouard, Pei Sun, Jiquan Ngiam, Vijay Vasudevan, Alexander McCauley, Jonathon Shlens, and Dragomir Anguelov. Large scale interactive motion forecasting for autonomous driving: The Waymo open motion dataset. In ICCV, 2021. 1" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 469, + 287, + 511 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 469, + 287, + 511 + ], + "spans": [ + { + "bbox": [ + 53, + 469, + 287, + 511 + ], + "type": "text", + "content": "[9] Lue Fan, Yuxue Yang, Feng Wang, Naiyan Wang, and Zhaoxiang Zhang. Super sparse 3D object detection. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2023. 6" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 514, + 287, + 545 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 514, + 287, + 545 + ], + "spans": [ + { + "bbox": [ + 48, + 514, + 287, + 545 + ], + "type": "text", + "content": "[10] Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, 2022. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 547, + 287, + 579 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 547, + 287, + 579 + ], + "spans": [ + { + "bbox": [ + 48, + 547, + 287, + 579 + ], + "type": "text", + "content": "[11] Adam W Harley, Zhaoyuan Fang, Jie Li, Rares Ambrus, and Katerina Fragkiadaki. Simple-BEV: What really matters for multi-sensor BEV perception? In ICRA, 2023. 1, 3, 4, 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 581, + 287, + 633 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 581, + 287, + 633 + ], + "spans": [ + { + "bbox": [ + 48, + 581, + 287, + 633 + ], + "type": "text", + "content": "[12] Anthony Hu, Zak Murez, Nikhil Mohan, Sofia Dudas, Jeffrey Hawke, Vijay Badrinarayanan, Roberto Cipolla, and Alex Kendall. FIERY: Future instance prediction in Bird's-Eye View from surround monocular cameras. In ICCV, 2021. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 635, + 287, + 667 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 635, + 287, + 667 + ], + "spans": [ + { + "bbox": [ + 48, + 635, + 287, + 667 + ], + "type": "text", + "content": "[13] Qi Li, Yue Wang, Yilun Wang, and Hang Zhao. HDMapNet: An online hd map construction and evaluation framework. In ICRA, 2022. 1, 3, 5, 6, 7, 9" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 670, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 287, + 712 + ], + "type": "text", + "content": "[14] Yinhao Li, Zheng Ge, Guanyi Yu, Jinrong Yang, Zengran Wang, Yukang Shi, Jianjian Sun, and Zeming Li. BEVDepth: Acquisition of reliable depth for multi-view 3D object detection. In AAAI, 2023. 3" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 31, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 126 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 126 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 126 + ], + "type": "text", + "content": "[15] Zhiqi Li, Wenhai Wang, Hongyang Li, Enze Xie, Chonghao Sima, Tong Lu, Yu Qiao, and Jifeng Dai. BEVFormer: Learning Bird's-Eye-View representation from multi-camera images via spatiotemporal transformers. In ECCV, 2022. 1, 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 129, + 545, + 172 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 129, + 545, + 172 + ], + "spans": [ + { + "bbox": [ + 307, + 129, + 545, + 172 + ], + "type": "text", + "content": "[16] Benchcheng Liao, Shaoyu Chen, Xinggang Wang, Tianheng Cheng, Qian Zhang, Wenyu Liu, and Chang Huang. MapTR: Structured modeling and learning for online vectorized HD map construction. In ICLR, 2023. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 175, + 545, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 175, + 545, + 205 + ], + "spans": [ + { + "bbox": [ + 307, + 175, + 545, + 205 + ], + "type": "text", + "content": "[17] Lingjie Liu, Jiatao Gu, Kyaw Zaw Lin, Tat-Seng Chua, and Christian Theobalt. Neural sparse voxel fields. In NeurIPS, 2020. 3" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 208, + 545, + 240 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 208, + 545, + 240 + ], + "spans": [ + { + "bbox": [ + 307, + 208, + 545, + 240 + ], + "type": "text", + "content": "[18] Yicheng Liu, Yuan Yuantian, Yue Wang, Yilun Wang, and Hang Zhao. VectorMapNet: End-to-end vectorized HD map learning. In ICML, 2023. 3, 7" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 242, + 545, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 242, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 307, + 242, + 545, + 285 + ], + "type": "text", + "content": "[19] Zhijian Liu, Haotian Tang, Alexander Amini, Xingyu Yang, Huizi Mao, Daniela Rus, and Song Han. BEVFusion: Multi-task multi-sensor fusion with unified Bird's-Eye View representation. In ICRA, 2023. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 287, + 545, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 287, + 545, + 330 + ], + "spans": [ + { + "bbox": [ + 307, + 287, + 545, + 330 + ], + "type": "text", + "content": "[20] Ricardo Martin-Brualla, Noha Radwan, Mehdi S. M. Sajjadi, Jonathan T. Barron, Alexey Dosovitskiy, and Daniel Duckworth. NeRF in the wild: Neural radiance fields for unconstrained photo collections. In CVPR, 2021. 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 332, + 545, + 364 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 332, + 545, + 364 + ], + "spans": [ + { + "bbox": [ + 307, + 332, + 545, + 364 + ], + "type": "text", + "content": "[21] Tim Meinhardt, Alexander Kirillov, Laura Leal-Taixe, and Christoph Feichtenhofer. TrackFormer: Multi-object tracking with transformers. In CVPR, 2022. 6" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 366, + 545, + 408 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 366, + 545, + 408 + ], + "spans": [ + { + "bbox": [ + 307, + 366, + 545, + 408 + ], + "type": "text", + "content": "[22] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan Barron, Ravi Ramamoorthi, and Ren Ng. NeRF: Representing scenes as neural radiance fields for view synthesis. In ECCV, 2020. 2, 3, 5" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 411, + 545, + 443 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 411, + 545, + 443 + ], + "spans": [ + { + "bbox": [ + 307, + 411, + 545, + 443 + ], + "type": "text", + "content": "[23] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Trans. Graph., 2022. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 445, + 545, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 445, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 307, + 445, + 545, + 487 + ], + "type": "text", + "content": "[24] Mahyar Najibi, Jingwei Ji, Yin Zhou, Charles R Qi, Xinchen Yan, Scott Ettinger, and Dragomir Anguelov. Motion inspired unsupervised perception and prediction in autonomous driving. In ECCV, 2022. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 490, + 545, + 553 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 490, + 545, + 553 + ], + "spans": [ + { + "bbox": [ + 307, + 490, + 545, + 553 + ], + "type": "text", + "content": "[25] Thomas Neff, Pascal Stadlbauer, Mathias Parger, Andreas Kurz, Joerg H. Mueller, Chakravarty R. Alla Chaitanya, Anton S. Kaplanyan, and Markus Steinberger. DONeRF: Towards real-time rendering of compact neural radiance fields using depth oracle networks. In Computer Graphics Forum, 2021. 3" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 557, + 545, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 557, + 545, + 600 + ], + "spans": [ + { + "bbox": [ + 307, + 557, + 545, + 600 + ], + "type": "text", + "content": "[26] Mong H. Ng, Kaahan Radia, Jianfei Chen, Dequan Wang, Ionel Gog, and Joseph E Gonzalez. BEV-Seg: Bird's Eye View semantic segmentation using geometry and semantic point cloud. arXiv preprint arXiv:2006.11436, 2020. 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 602, + 545, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 602, + 545, + 643 + ], + "spans": [ + { + "bbox": [ + 307, + 602, + 545, + 643 + ], + "type": "text", + "content": "[27] Bowen Pan, Jiankai Sun, Ho Yin Tiga Leung, Alex Andonian, and Bolei Zhou. Cross-view semantic segmentation for sensing surroundings. IEEE Robotics and Automation Letters, 2020. 3" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 647, + 545, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 647, + 545, + 678 + ], + "spans": [ + { + "bbox": [ + 307, + 647, + 545, + 678 + ], + "type": "text", + "content": "[28] Ziqi Pang, Zhichao Li, and Naiyan Wang. Model-free vehicle tracking and state estimation in point cloud sequences. In IROS, 2021. 2" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 681, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 681, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 681, + 545, + 712 + ], + "type": "text", + "content": "[29] Jonah Philion and Sanja Fidler. Lift, Splat, Shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3D. In ECCV, 2020. 3, 6" + } + ] + } + ], + "index": 30 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8667" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "type": "text", + "content": "[30] Charles R Qi, Yin Zhou, Mahyar Najibi, Pei Sun, Khoa Vo, Boyang Deng, and Dragomir Anguelov. Offboard 3D object detection from point cloud sequences. In CVPR, 2021. 2, 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 106, + 288, + 160 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 106, + 288, + 160 + ], + "spans": [ + { + "bbox": [ + 48, + 106, + 288, + 160 + ], + "type": "text", + "content": "[31] Lennart Reiher, Bastian Lampe, and Lutz Eckstein. A Sim2Real deep learning approach for the transformation of images from multiple vehicle-mounted cameras to a semantically segmented image in Bird's Eye View. In ITSC, 2020. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 161, + 288, + 204 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 161, + 288, + 204 + ], + "spans": [ + { + "bbox": [ + 48, + 161, + 288, + 204 + ], + "type": "text", + "content": "[32] Konstantinos Rematas, Andrew Liu, Pratul P. Srinivasan, Jonathan T. Barron, Andrea Tagliasacchi, Tom Funkhouser, and Vittorio Ferrari. Urban radiance fields. In CVPR, 2022. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 205, + 288, + 249 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 205, + 288, + 249 + ], + "spans": [ + { + "bbox": [ + 48, + 205, + 288, + 249 + ], + "type": "text", + "content": "[33] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In Medical Image Computing and Computer-Assisted Intervention (MICCAI), 2015. 4" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 250, + 288, + 271 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 250, + 288, + 271 + ], + "spans": [ + { + "bbox": [ + 48, + 250, + 288, + 271 + ], + "type": "text", + "content": "[34] Johannes Lutz Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In CVPR, 2016. 2, 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 271, + 288, + 304 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 271, + 288, + 304 + ], + "spans": [ + { + "bbox": [ + 48, + 271, + 288, + 304 + ], + "type": "text", + "content": "[35] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In CVPR, 2022. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 304, + 288, + 338 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 304, + 288, + 338 + ], + "spans": [ + { + "bbox": [ + 48, + 304, + 288, + 338 + ], + "type": "text", + "content": "[36] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Improved direct voxel grid optimization for radiance fields reconstruction. arXiv preprint arXiv:2206.05085, 2022. 3, 5" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 338, + 288, + 381 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 338, + 288, + 381 + ], + "spans": [ + { + "bbox": [ + 48, + 338, + 288, + 381 + ], + "type": "text", + "content": "[37] Matthew Tancik, Vincent Casser, Xinchen Yan, Sabeek Pradhan, Ben Mildenhall, Pratul Srinivasan, Jonathan T. Barron, and Henrik Kretzschmar. Block-NeRF: Scalable large scene neural view synthesis. In CVPR, 2022. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 383, + 288, + 425 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 383, + 288, + 425 + ], + "spans": [ + { + "bbox": [ + 48, + 383, + 288, + 425 + ], + "type": "text", + "content": "[38] Yi Wei, Shaohui Liu, Yongming Rao, Wang Zhao, Jiwen Lu, and Jie Zhou. NerfingMVS: Guided optimization of neural radiance fields for indoor multi-view stereo. In ICCV, 2021. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 426, + 288, + 514 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 426, + 288, + 514 + ], + "spans": [ + { + "bbox": [ + 48, + 426, + 288, + 514 + ], + "type": "text", + "content": "[39] Benjamin Wilson, William Qi, Tanmay Agarwal, John Lambert, Jagjeet Singh, Siddhesh Khandelwal, Bowen Pan, Ratnesh Kumar, Andrew Hartnett, Jhony Kaesemodel Pontes, Deva Ramanan, Peter Carr, and James Hays. Argoverse 2: Next generation datasets for self-driving perception and forecasting. In Proceedings of the Neural Information Processing Systems Track on Datasets and Benchmarks (NeurIPS Datasets and Benchmarks 2021, 2023. 1" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 514, + 288, + 546 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 514, + 288, + 546 + ], + "spans": [ + { + "bbox": [ + 48, + 514, + 288, + 546 + ], + "type": "text", + "content": "[40] Ziyang Xie, Junge Zhang, Wenye Li, Feihu Zhang, and Li Zhang. S-NeRF: Neural radiance fields for street views. In ICLR, 2023. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 547, + 288, + 580 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 547, + 288, + 580 + ], + "spans": [ + { + "bbox": [ + 48, + 547, + 288, + 580 + ], + "type": "text", + "content": "[41] Xuan Xiong, Yicheng Liu, Tianyuan Yuan, Yue Wang, Yilun Wang, and Hang Zhao. Neural map prior for autonomous driving. In CVPR, 2023. 3, 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 581, + 288, + 613 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 581, + 288, + 613 + ], + "spans": [ + { + "bbox": [ + 48, + 581, + 288, + 613 + ], + "type": "text", + "content": "[42] Qiangeng Xu, Zexiang Xu, Julien Philip, Sai Bi, Zhixin Shu, Kalyan Sunkavalli, and Ulrich Neumann. Point-NeRF: Point-based neural radiance fields. In CVPR, 2022. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 614, + 288, + 647 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 614, + 288, + 647 + ], + "spans": [ + { + "bbox": [ + 48, + 614, + 288, + 647 + ], + "type": "text", + "content": "[43] Bin Yang, Min Bai, Ming Liang, Wenyuan Zeng, and Raquel Urtasun. Auto4D: Learning to label 4D objects from sequential point clouds. arXiv preprint arXiv:2101.06586, 2021. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 647, + 288, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 288, + 679 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 288, + 679 + ], + "type": "text", + "content": "[44] Yao Yao, Zixin Luo, Shiwei Li, Tian Fang, and Long Quan. MVSNet: Depth inference for unstructured multiview stereo. In ECCV, 2018. 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 680, + 288, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 680, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 680, + 288, + 713 + ], + "type": "text", + "content": "[45] Weihao Yuan, Xiaodong Gu, Zuozhuo Dai, Siyu Zhu, and Ping Tan. NeWCRFs: Neural window fully-connected CRFs for monocular depth estimation. In CVPR, 2022. 8, 9" + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 72, + 545, + 152 + ], + "type": "list", + "angle": 0, + "index": 19, + "blocks": [ + { + "bbox": [ + 307, + 72, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 72, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 72, + 545, + 106 + ], + "type": "text", + "content": "[46] Fangao Zeng, Bin Dong, Yuang Zhang, Tiancai Wang, Xi-angyu Zhang, and Yichen Wei. MOTR: End-to-end multiple-object tracking with transformer. In ECCV, 2022. 6" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 107, + 545, + 152 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 152 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 152 + ], + "type": "text", + "content": "[47] Xi Zhu, Xiya Cao, Zhiwei Dong, Caifa Zhou, Qiangbo Liu, Wei Li, and Yongliang Wang. Nemo: Neural map growing system for spatiotemporal fusion in bird's-eye-view and bdd-map benchmark. arXiv preprint arXiv:2306.04540, 2023. 3" + } + ] + } + ], + "index": 18 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8668" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/0b36b82c-cf6a-406b-8b06-65bc02693944_content_list.json b/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/0b36b82c-cf6a-406b-8b06-65bc02693944_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..d0f37ddeeab04638723a13b886e21c92055aadd0 --- /dev/null +++ b/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/0b36b82c-cf6a-406b-8b06-65bc02693944_content_list.json @@ -0,0 +1,1705 @@ +[ + { + "type": "text", + "text": "MVPSNet: Fast Generalizable Multi-view Photometric Stereo", + "text_level": 1, + "bbox": [ + 173, + 130, + 797, + 151 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Dongxu Zhao $^{1}$ Daniel Lichy $^{2}$ Pierre-Nicolas Perrin $^{1}$ Jan-Michael Frahm $^{1}$ Soumyadip Sengupta $^{1}$", + "bbox": [ + 84, + 191, + 880, + 212 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1University of North Carolina at Chapel Hill 2University of Maryland, College Park", + "bbox": [ + 143, + 222, + 823, + 241 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{dongxuzl, pnperrin, jmf, ronisen}@cs.unc.edu dlichy@umd.edu", + "bbox": [ + 204, + 243, + 764, + 258 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 304, + 313, + 320 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "We propose a fast and generalizable solution to Multiview Photometric Stereo (MVPS), called MVPSNet. The key to our approach is a feature extraction network that effectively combines images from the same view captured under multiple lighting conditions to extract geometric features from shading cues for stereo matching. We demonstrate these features, termed 'Light Aggregated Feature Maps' (LAFM), are effective for feature matching even in textureless regions, where traditional multi-view stereo methods often fail. Our method produces similar reconstruction results to PS-NeRF, a state-of-the-art MVPS method that optimizes a neural network per-scene, while being $411 \\times$ faster (105 seconds vs. 12 hours) in inference. Additionally, we introduce a new synthetic dataset for MVPS, sMVPS, which is shown to be effective for training a generalizable MVPS method.", + "bbox": [ + 73, + 335, + 472, + 577 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 603, + 209, + 619 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "3D reconstruction of an object can be achieved either through camera viewpoint variations, Multi-view Stereo (MVS), or by lighting direction variations, Photometric Stereo (PS). Both MVS and PS have relative strengths and weaknesses. While MVS succeeds in obtaining accurate global shapes, it suffers in textureless regions due to poor feature matching, often resulting in reconstructions that lack local details. On the other hand, PS produces accurate local details, even in textureless regions, by using shading information but fails to reconstruct accurate global shapes. In this paper, we focus on the problem of Multi-view Photometric Stereo (MVPS) where both camera viewpoint and lighting direction variations are used to accurately reconstruct global and local details of a 3D shape, even in textureless regions.", + "bbox": [ + 73, + 628, + 468, + 854 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "3D reconstruction techniques that produce high-quality results using only viewpoint variations (MVS) rely on test-time optimization, often by training neural networks per", + "bbox": [ + 75, + 854, + 468, + 901 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "scene [53, 64, 66]. These methods are computationally inefficient, typically taking hours of computing time on a high-end GPU for each object. Existing MVs methods [20, 56, 62] that focus on computational efficiency employ feed-forward neural networks that are efficient but fail to produce high-quality details, especially in textureless regions. Existing MVPS approaches can produce high-quality reconstructions but require computationally inefficient per-scene training or optimization [27, 28, 29, 61]. Sometimes additional manual efforts and carefully crafted refinement steps are also needed [34, 47]. In contrast, we propose an efficient feed-forward neural architecture, MVPSNet, that can generalize to unseen objects and achieve similar reconstruction quality to that of per-scene optimization techniques while being computationally efficient during inference.", + "bbox": [ + 496, + 304, + 893, + 546 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "We design MVPSNet by taking inspiration from various deep MVS architectures [7, 14, 18, 20, 62] that are generalizable, computationally efficient, and can operate on high-resolution images. However, these approaches often fail in textureless regions, and their reconstructed meshes often lack details. We choose the CasMVsNet [20] architecture as our feature matching module, which has been repeatedly used by various MVS pipelines [7, 14, 18] for its simplicity and efficiency, and augment it to effectively incorporate lighting variation cues for better prediction of 3D shapes. In this way, we propose a feed-forward generalizable approach to Multi-view Photometric Stereo.", + "bbox": [ + 496, + 549, + 893, + 731 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "We introduce a multi-scale feature representation, called Light Aggregated Feature Maps (LAFM), whose role is to extract detailed geometric features from images by utilizing lighting variations. For brevity, we define Multi-light Images as a collection of images taken from the same viewpoint under different directional lighting conditions. Our intuition is that LAFM can efficiently aggregate shading patterns from multi-light images, by creating an 'artificial shading texture' in the textureless region. Multi-scale LAFM will then be used to construct a sequence of cost volumes to match features across sparse views in order to", + "bbox": [ + 496, + 734, + 895, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 805, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "12525", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "predict a depth map for a reference view. We also predict surface normals from LAFM for each viewpoint, enabling LAFM to capture features related to high-frequency local details. The predicted surface normal can be used in addition to the depth maps to produce a more detailed mesh than using the depth maps alone.", + "bbox": [ + 75, + 90, + 468, + 181 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To train the proposed MVPSNet architecture, we introduce a new synthetic MVPS dataset, sMVPS dataset. It consists of shapes from sculpture dataset [57] and random compositions of primitive shapes generated by [60]. We render these shapes with spatially varying Cook-Torrance BRDF under different camera viewpoints and lighting directions. We train MVPSNet on these rendered images with ground-truth supervision over predicted depth and surface normal maps. The trained model generalizes to real-world test scenes from DiLiGenT-MV [34] dataset. We show that simply re-training CasMVsNet on our dataset improves reconstruction quality over the pre-trained model on DiLiGenT-MV by $32\\%$ , proving the effectiveness of our synthetic MVPS dataset for generalization.", + "bbox": [ + 75, + 181, + 470, + 393 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We evaluate our approach on the only publicly available MVPS benchmark, the DiLiGenT-MV [34] dataset. Compared to the state-of-the-art MVPS technique, PS-NeRF [61], which optimizes a neural network per-scene, our proposed MVPSNet is $\\sim 411\\times$ faster (105 seconds vs 12 hours) while producing similar reconstruction quality (L1 Chamfer distance of 0.82 vs 0.81, F-score on L2 distance of 0.985 vs 0.983). We further show that adding LAFM significantly improves reconstruction quality over CasMVSNet by $34\\%$ in L1 Chamfer distance. We also observe that refining the reconstructed mesh derived from depth maps with predicted surface normals from LAFM improves reconstruction quality as shown in Fig 3.", + "bbox": [ + 75, + 393, + 470, + 589 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In summary, the key contributions of this paper include: - Light Aggregated Feature Maps (LAFM) that can efficiently utilize multi-light images to extract detailed geometric features, especially in textureless regions. The surface normal predicted from LAFM also improves mesh reconstruction quality. - A synthetic MVPS dataset for training generalizable MVPS methods, which also improves Cas-MVSNet by $32\\%$ . - A fast and generalizable Multi-view Photometric Stereo pipeline that is $411\\times$ faster while producing similar reconstruction accuracy compared to state-of-the-art per-scene optimization approach [61].", + "bbox": [ + 75, + 589, + 468, + 755 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related work", + "text_level": 1, + "bbox": [ + 76, + 768, + 215, + 786 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Multi-view Stereo (MVS). MVS is a 3D reconstruction technique that utilizes multiple images captured from different viewpoints. While various techniques for MVS have been proposed, one commonly used approach that is relevant to our work involves constructing cost volumes similar to Plane Sweeping Algorithm [13] and then predicting per-view depth maps [21, 25, 41, 59, 62, 63] or disparity", + "bbox": [ + 75, + 794, + 467, + 902 + ], + "page_idx": 1 + }, + { + "type": "table", + "img_path": "images/49f252500429201f351fdbd5958129fcdf8924839e2bda44c49244466ef8821e.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodGeneralizableMesh Reconstruction
PJ16 [47]XBase mesh+displacement map
LZ20 [34]X3D points+PSR [30]+Optimization [44]
BKW22 [29]XMLP+Marching Cube [40]
BKC22 [27]XMLP+Marching Cube [40]
PS-NeRF [61]XMLP+MISE [42]
BKW23 [28]XMLP+Marching Cube [40]
Ours✓3D Points+Screened Poisson [31]
", + "bbox": [ + 509, + 88, + 883, + 174 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Table 1. Comparison of our method with prior MVPS methods.", + "bbox": [ + 500, + 183, + 875, + 196 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "maps [23]. To create a cost volume, features are matched across neighboring viewpoints, and the quality of the features plays a critical role in the final reconstruction quality. Traditional methods [5, 16, 17, 19, 26, 50, 54, 55] use human-defined or hand-crafted image processing operators to extract feature maps. With recent advances in deep learning, features learned from deep neural networks have been proven to be effective.", + "bbox": [ + 496, + 228, + 890, + 348 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The most relevant previous works are MVSNet [62] and its variations. MVSNet [62] uses homography to warp feature maps and a 3D CNN to regularize cost volumes. CasMVSNet [21] outperforms MVSNet in terms of accuracy and efficiency by building the 3D cost volume in a cascaded manner. TransMVSNet [15] builds upon CasMVSNet and adopts a transformer to consider intra-image and inter-image feature interactions, which further improves the results of CasMVSNet.", + "bbox": [ + 496, + 351, + 892, + 487 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Photometric Stereo (PS). PS (introduced in [58]) uses lighting variation to reconstruct 3D shapes from a single viewpoint (see [52] for surveys). Calibrated PS approaches, like Chen et al. [10], train a neural network to predict surface normals using data with known lightings. Uncalibrated PS approaches [8, 9, 11] first predict the lighting parameters before solving for surface normals. While most PS works use a large number of images for inference, some use fewer [24, 38], or even one image [6, 35, 36, 51] (often called Shape from Shading). PS approaches are mostly based on feed-forward networks that generalize and can produce near real-time inference with low computational cost [37].", + "bbox": [ + 496, + 489, + 892, + 671 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Multi-view Photometric Stereo (MVPS). MVPS was initially proposed in [22] by combining PS with object silhouettes to reconstruct textureless shiny objects with fine details. However, this method only works well for specific parametric BRDF models [27]. Later, Li et al. [34, 68] propose to get iso-depth contours from PS images and sparse 3D points using structure-from-motion, which are propagated to recover a complete 3D shape. Park et al. [46, 47] use a planar mesh parameterization technique to parameterize a coarse mesh from MVS and take advantage of this 2D parameter domain to perform MVPS. Some of these traditional MVPS methods achieve high-quality results, but they require an initial 3D reconstruction and their performance is sensitive to it. Besides, they consist of multiple steps, so careful execution or expert interventions are often needed to", + "bbox": [ + 496, + 674, + 892, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "12526", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/6911031e21945bca173a6154e01d13dc53a995dc430952499b2012169efb6715.jpg", + "image_caption": [ + "Figure 1. Overview of our network architecture. (a) Light Informed Feature Extractor (LIFE) produces a multi-scale feature representation; (b) Light Aggregated Feature Maps (LAFM) Extractor aggregates these features across images of varying lighting conditions but same view; and (c) LAFM is used to create cost volumes and predict depth maps, similar to CasMVSNet [21], in addition to normal map." + ], + "image_footnote": [], + "bbox": [ + 101, + 88, + 321, + 333 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/d95403bcd3b4219a6a8dce8c49c8505fe7927ee77ed320b502b3d0a23426d26d.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 323, + 88, + 566, + 333 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/49d73e923de6170f4d63a0b10ec766f3f63222806a5910c6638ebbc67d16d910.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 566, + 88, + 870, + 333 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "get good results [34, 47]. In contrast, our proposed method trains a neural network end-to-end and the inference only requires one feed-forward pass of the trained network.", + "bbox": [ + 75, + 415, + 468, + 460 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Recently, inspired by NeRF [43], various algorithms have been proposed that optimize a neural network perscene for MVPS. Kaya et al. [29] train a deep PS network first and condition the color rendering in NeRF [43] on normals predicted from PS. The reconstructed mesh, however, exhibits multiple artifacts. The authors in [27] propose to train a deep PS network and a deep MVS network extended with uncertainty estimation separately, and use these to fit the SDF represented by an MLP. To further enable reconstruction on anisotropic and glossy objects, Kaya et al. [28] add a neural volume rendering module to the SDF MLP in [27] to better fuse PS and MVS measurements. PS-NeRF [61] solves the task of jointly estimating the geometry, materials and lights. It first regularizes the gradient of a UNISURF [45] with estimated normals from PS, and then uses separate MLPs to explicitly model surface normal, BRDF, lights, and visibility which are optimized based on a shadow-aware differentiable rendering layer. Recent works have also used physically based differentiable rendering either inside a NeRF framework [3] or separately for optimization [65]. While per-scene optimization methods often generate precise reconstruction results, they have to optimize an individual model for each object separately, which is computationally inefficient. Thus, we propose a solution to Multi-view Photometric Stereo training on a new synthetic MVPS dataset, which is generalizable and can achieve similar results as SOTA per-scene optimization methods.", + "bbox": [ + 75, + 477, + 472, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Our approach", + "text_level": 1, + "bbox": [ + 500, + 414, + 643, + 431 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Problem setup", + "text_level": 1, + "bbox": [ + 500, + 439, + 648, + 455 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We focus on the problem of calibrated multi-view photometric stereo, i.e. the locations of the light sources and the cameras are known a priori (calibrated prior to capture). The input data consists of a set of multi-light images of an object captured from multiple views.", + "bbox": [ + 496, + 462, + 890, + 537 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Concretely, for the $i$ -th view we have $M_{i}$ images with varying lighting directions $l_{ij}$ , denoted as $I_{ij}$ . We refer to the collection $\\{I_{i1}, \\dots, I_{iM_i}\\}$ as the multi-light images for the $i$ -th view. For each view, we are given camera intrinsic matrix $K_{i}$ and camera extrinsic parameters in the form of a rotation matrix, $R_{i}$ , and a translation vector, $t_i$ . Similar to virtually all MVS methods, we assume that we are provided with the depth range for each view.", + "bbox": [ + 496, + 537, + 892, + 657 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Motivation", + "text_level": 1, + "bbox": [ + 500, + 665, + 622, + 680 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Our approach follows a long line of work in Multi-view Stereo which uses Plane Sweep to construct a cost volume and predicts a depth map aligned with a reference image. Recent advances in Plane Sweep Stereo using deep neural networks, especially CasMVSNet [21], have proven to be generalizable across scenes and can predict high-resolution reconstruction in a matter of seconds. In contrast to previous Multi-view Photometric Stereo approaches, which optimize a neural network per scene, our goal is to produce a generalizable solution. Thus we aim to build upon the Plane Sweep stereo architecture proposed in CasMVSNet [21].", + "bbox": [ + 496, + 688, + 890, + 853 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "CasMVSNet learns a deep image feature encoder for extracting representative features that can aid in feature matching across multiple views and create better cost vol", + "bbox": [ + 496, + 854, + 892, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "12527", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "umes. However, these features are often ambiguous for non-textured regions and fail to preserve the geometric details. We believe incorporating lighting variations along with viewpoint variations can lead to better features, which in turn will produce better cost volumes and depth maps.", + "bbox": [ + 75, + 90, + 468, + 167 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To this end, we introduce 'Light Aggregated Feature Maps' (LAFM), whose goal is to extract detailed geometric features, even for textureless regions, by jointly learning to aggregate feature maps over all images captured from a single viewpoint and multiple lighting directions. To obtain effective features that capture geometric details we use LAFM to regress surface normals. We show that LAFM provide superior information for stereo-matching than single-lighting feature maps (as used in CasMVSNet) and thus provide a better reconstruction. We also show that surface normals predicted using LAFM can be used during mesh reconstruction to improve quality over depth maps alone.", + "bbox": [ + 75, + 167, + 468, + 348 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Our approach proceeds in three stages. We first extract multi-scale feature representation from each image, along with its lighting directions, using a shared neural network, 'Light Informed Feature Extractor' (LIFE). To aggregate features extracted by LIFE across all images under the same viewpoint but different lighting conditions, we use max-pooling operation. We can then create a cost volume for the reference view by matching LAFM of the reference view with all the LAFM from neighboring views. Finally, for each reference view, we predict a depth map using cost volume regularization and a surface normal map from the LAFM. We train our system in a multi-task learning framework with supervised losses over depth and normal predictions. In the following sections, we provide the details of our MVPSNet pipeline. An overview of MVPSNet architecture is illustrated in Figure 1.", + "bbox": [ + 75, + 349, + 470, + 592 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Light Aggregated Feature Maps (LAFM)", + "text_level": 1, + "bbox": [ + 76, + 603, + 428, + 619 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We introduce Light Aggregated Feature Maps (LAFM) that provide geometrically distinct multi-scale features for cost volume creation in a Plane Sweep Stereo approach. Our key observation is that the multi-light images provide us with important information for feature matching. For textureless regions, the variation in shading (including cast and attached shadows) created by different lighting directions can be interpreted as 'artificial' textures. Thus the role of LAFM for textureless regions is to capture the variation in shading as an 'artificial' texture that can be used for feature matching across different viewpoints. We also use LAFM to predict surface normal maps, enabling it to capture geometric details required for producing high-quality normal maps. Hence LAFM can capture better features for textureless regions and for reconstructing details, which were absent in the usual deep image features used in deep multi-view stereo algorithms.", + "bbox": [ + 75, + 627, + 468, + 883 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We first define a multi-scale feature extractor, Light In", + "bbox": [ + 96, + 885, + 467, + 900 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "formed Feature Extractor (LIFE), that takes an image $I_{ij}$ associated with its lighting direction $l_{ij}$ as input and produces feature maps at three different scales $F_{ij}^{1}, F_{ij}^{2}, F_{ij}^{3}$ at resolutions $1/4, 1/2, 1$ of the input resolution, and another feature map $NF_{ij}$ that will be used for normal prediction. The network architecture of LIFE is shown in Fig. 1(a) and will be discussed in details in the supplementary material.", + "bbox": [ + 496, + 90, + 890, + 196 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nN F _ {i j}, F _ {i j} ^ {1}, F _ {i j} ^ {2}, F _ {i j} ^ {3} = L I F E \\left(I _ {i j}, l _ {i j}; \\theta\\right) \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 562, + 205, + 890, + 223 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Note $l_{ij}$ is of the same resolution as $I_{ij}$ by simply repeating the same 3-dimensional lighting vector at each pixel.", + "bbox": [ + 496, + 222, + 890, + 252 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Then we extract these multi-scale features for every image captured under the same viewpoint and different lighting conditions, $\\{I_{i1},\\dots,I_{iM_i}\\}$ , using the same shared encoder LIFE. Let the feature maps obtained from these images be denoted as: $\\{NF_{ij},F_{ij}^{1},F_{ij}^{2},F_{ij}^{3}\\}$ , $j = 1,\\dots,M_i$ . We create 'Light Aggregated Feature Maps' (LAFM) from these multi-scale feature representations by performing a max-pooling operation for each scale. Pooling operations can handle various numbers of input feature maps and are order-agnostic. Moreover, max-pooling helps save the most prominent feature across all views and ignores non-activated features, which automatically handles shadows casted by directional lights [10].", + "bbox": [ + 496, + 253, + 890, + 448 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nF _ {i} ^ {s} = \\max _ {j} F _ {i j} ^ {s}, \\quad \\forall s = 1, 2, 3 \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 599, + 449, + 890, + 472 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nN F _ {i} = \\max _ {j} N F _ {i j}. \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 589, + 476, + 890, + 498 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Thus for multi-light images we obtain LAFM as $LF_{i} = \\{NF_{i},F_{i}^{1},F_{i}^{2},F_{i}^{3}\\}$", + "bbox": [ + 500, + 498, + 890, + 527 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The features at 3 scales $F_{i}^{1}, F_{i}^{2}, F_{i}^{3}$ are then used to build cost volumes using differentiable homography warping, which we will talk about in detail in Section 3.4. The normal feature $NF_{i}$ is fed into a lightweight normal regression network to predict per-view normal map, as shown in Figure 1(c). With the supervision from normal information and depth information, our LAFM benefit from the advantages of both MVS and PS which are good at global shape modeling and high-frequency component reconstruction, respectively.", + "bbox": [ + 496, + 529, + 890, + 680 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.4. Cost volume and depth map prediction", + "text_level": 1, + "bbox": [ + 500, + 693, + 833, + 709 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Given Light Aggregated Feature Maps (LAFM), $LF_{i}$ for each view $i$ , we aim to build a cost volume for each reference view by selecting a set of source views with sufficient overlap. We adopt the multi-scale cost volume construction proposed in CasMVSNet [21], where the plane sweep is first performed at a low resolution and then at higher resolutions. Depth estimated from the previous step is used for generating depth proposals for the next step. Multi-scale cost volume reconstruction and depth map prediction follow the following steps.", + "bbox": [ + 496, + 717, + 890, + 868 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Step 1: Depth hypothesis generation. We generate hypothesis depths for each pixel based on the lower resolution", + "bbox": [ + 498, + 869, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "12528", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "depth estimated at the previous resolution. We store these in $h$ , where", + "bbox": [ + 75, + 90, + 468, + 119 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nh (u, v, w) = U p \\left(D ^ {s - 1}\\right) (u, v) + \\Delta_ {s} \\left(\\frac {w}{N _ {s} - 1} - \\frac {1}{2}\\right). \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 89, + 119, + 468, + 148 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Here $h(u,v,w)$ is the $w$ -th depth hypothesis at pixel $(u,v)$ . $Up(D^{s - 1})$ is the depth map at the previous lower resolution upsampled to the current resolution. $\\Delta_s$ is the length of the depth interval we are searching at scale $s$ . $N_{s}$ is the number of hypothesis depths at the current scale.", + "bbox": [ + 75, + 147, + 468, + 222 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Step 2: Cost volume construction. Building cost volume is a way of robustly searching for matches between a point $(u, v)$ in the reference image $I_r$ and a point on the corresponding epipolar line in the source image $I_{s_k}$ . Concretely, consider a pixel $(u, v)$ in the reference image. For every hypothesis depth $d$ , we get a corresponding point in the source image on the epipolar line for $(u, v)$ . We denote this point by $(u', v') = \\mathrm{warp}_{rs_k}(u, v, d)$ where", + "bbox": [ + 75, + 222, + 468, + 345 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\left[ \\begin{array}{l} u ^ {\\prime} \\\\ v ^ {\\prime} \\\\ 1 \\end{array} \\right] \\sim K _ {s _ {k}} R _ {s _ {k}} ^ {T} \\left[ \\left(R _ {r} K _ {r} ^ {- 1} d \\left[ \\begin{array}{l} u \\\\ v \\\\ 1 \\end{array} \\right] + t _ {r}\\right) - t _ {s} \\right]. \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 94, + 347, + 468, + 393 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We then construct a per-image volume:", + "bbox": [ + 96, + 397, + 356, + 411 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nF _ {i} \\operatorname {v o l} _ {i} ^ {s} (u, v, w) = F _ {i} ^ {s} \\left(w a r p (u, v, h (u, v, w))\\right), \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 116, + 411, + 468, + 428 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $i$ runs over the reference and source views i.e. $i \\in \\{r, s_1, \\dots, s_k\\}$ . These volumes are then aggregated into a single cost volume by taking their variance, which checks for the photo-consistency of the depth proposal $d$ for pixel $(u, v)$ in the reference image and the corresponding pixels in the warped sources images $s_k$ :", + "bbox": [ + 76, + 426, + 468, + 516 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {a g g} _ {-} \\operatorname {v o l} ^ {s} (u, v, w) = \\operatorname {v a r} _ {i} \\left(\\mathrm {F} _ {-} \\operatorname {v o l} (\\mathrm {u}, \\mathrm {v}, \\mathrm {w}) _ {i} ^ {s}\\right). \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 135, + 517, + 468, + 532 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Step 3: Cost regularization. In this step we pass the aggregated volume through a 3D convolutional network and take a softmax to convert it to a match probability, using", + "bbox": [ + 75, + 532, + 468, + 578 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {p r o b} _ {-} \\operatorname {v o l} = \\operatorname {s o f t} _ {-} \\max _ {w} \\left(\\operatorname {r e g} _ {-} \\operatorname {n e t} ^ {s} \\left(\\operatorname {a g g} _ {-} \\operatorname {v o l} ^ {s}\\right)\\right). \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 125, + 578, + 468, + 593 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Step 4: Regression. We take the expectation of the hypothesis depths over the match probability given by the probability volume to obtain the depth at the current scale, which enables sub-pixel estimation.", + "bbox": [ + 75, + 593, + 468, + 652 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nD ^ {s} (u, v) = \\sum_ {w} \\operatorname {p r o b} _ {-} \\operatorname {v o l} (u, v, w) h (u, v, w). \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 125, + 652, + 468, + 681 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "This whole process is summarized in algorithm 1", + "bbox": [ + 96, + 681, + 419, + 695 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Algorithm 1 MVPSNet Algorithm", + "text_level": 1, + "bbox": [ + 78, + 710, + 310, + 724 + ], + "page_idx": 4 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "1: $NF_{ij},F_{ij}^{1},F_{ij}^{2},F_{ij}^{3} = \\mathrm{LIFE}(I_{ij},l_{ij};\\theta)$", + "2: $NF_{i} = \\max_{j}NF_{ij};F_{i}^{s} = \\max_{j}F_{ij}^{s}\\quad \\forall s = 1,2,3.$", + "3: $N_{i} =$ normal_regression_net $(NF_{i})$", + "4: $D^0 (u,v) = (\\max_{-}\\mathrm{depth} + \\min_{-}\\mathrm{depth}) / 2$", + "5: for $s = 1$ to 3 do", + "6: $h(u,v,w) = Up(D^{s - 1})(u,v) + \\Delta_s(\\frac{w}{N_s - 1} -\\frac{1}{2})$", + "7: $\\mathrm{F\\_vol}_i^s (u,v,w) = F_i^s (warp(u,v,h(u,\\bar{v},w)))$", + "8: $\\mathrm{agg\\_vol}^s (u,v,w) = \\mathrm{var}_i(\\mathrm{F\\_vol}_i^s)$", + "9: prob_vol = soft_max_w(reg_net^s(agg_vol^s))", + "10: $D^{s}(u,v) = \\sum_{w}\\mathrm{prob\\_vol}(u,v,w)h(u,v,w)$", + "11: end for" + ], + "bbox": [ + 83, + 727, + 447, + 893 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/7f52ef90ed05c68cde359925a5676c48272332c0e235541284eef42d5954a149.jpg", + "image_caption": [ + "Figure 2. Example images from proposed synthetic MVPS dataset." + ], + "image_footnote": [], + "bbox": [ + 506, + 89, + 866, + 213 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Once we have depth and surface normal for each view, our mesh reconstruction pipeline consists of three steps: depth filtering, lifting depth and normal maps to a point cloud, and reconstructing the mesh using Screened Poisson [31] (See supplementary materials for details).", + "bbox": [ + 496, + 266, + 890, + 342 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.5. Synthetic MVPS dataset", + "text_level": 1, + "bbox": [ + 500, + 349, + 723, + 366 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "A key component of our method is that we can learn better features for stereo matching, especially in textureless regions, by learning features that incorporate multi-lighting cues. However, there is no existing MVPS dataset that is large enough for neural network training. Therefore, we generate a large-scale synthetic dataset, sMVPS, consisting of two sub-datasets, sMVPS-sculpture (800 train scenes/4 test scenes) and sMVPS-random (1000 train scenes/20 test scenes).", + "bbox": [ + 496, + 373, + 890, + 508 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "sMVPS-sculpture consists of objects from the sculpture dataset [57] while sMVPS-random includes objects composed of random primitives from [60]. The objects were generated following the method of [39] with spatially varying Cook-Torrance BRDF. We render images from 20 viewpoints surrounding the object approximately every $18^{\\circ}$ plus random jitter in position. For each view we render 10 randomly chosen directional light sources sampled uniformly on a $45^{\\circ}$ spherical cap centered at the camera's optical axis. In addition to the images, we render ground truth normals, depth, albedo, and roughness.", + "bbox": [ + 496, + 508, + 890, + 675 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.6. Training MVPSNet", + "text_level": 1, + "bbox": [ + 500, + 683, + 686, + 699 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We train MVPSNet with supervised loss over surface normal and depth using the ground-truth created within synthetic sMVPS dataset. For each reference view, we use 2 source views. And we randomly choose 3 lights out of 10 to train our model. The total loss is defined as:", + "bbox": [ + 496, + 705, + 890, + 781 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nL _ {m v p s} = \\lambda_ {d} \\cdot L _ {d} + \\lambda_ {n} \\cdot L _ {n}, \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 575, + 782, + 890, + 797 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nL _ {d} = \\sum_ {s = 1} ^ {3} \\lambda_ {d s} \\cdot L _ {d s}, \\forall s = 1, 2, 3 \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 599, + 801, + 890, + 842 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $L_{ds}$ and $L_{n}$ refer to the depth loss for scale $s$ and normal loss, respectively. For loss weights, we set $\\lambda_{n} = 1$ and $\\lambda_{d} = 10$ . The weights of each scale, $\\lambda_{ds} = 1$ , for $s = 1,2,3$ .", + "bbox": [ + 496, + 840, + 890, + 898 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "12529", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/13a47b1ec3332ec8176d4ece34eeac8ec02c9017eaad6f334ee9495469b877b7.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Per-scene optimizationGeneralizable
CategoryManual EffortStandaloneSingle-view PSMVSMVPS
MethodPJ16 [47]LZ20 [34]BKW22 [29]BKC22 [27]PS-NeRF [61]PS- Transformer [24]CasMVSNet [21]- RTTransMVSNet [15]- RTOurs
BEAR2.540.731.011.010.763.171.471.480.80
BUDDHA1.120.972.681.150.864.091.261.101.07
COW1.140.391.090.760.753.041.271.050.77
POT23.210.671.541.400.763.051.461.050.82
READING1.300.661.970.840.923.600.750.760.66
AVERAGE1.860.691.661.030.813.391.241.090.82
Recon. Time/object--7 hrs?12 hrs?22s52s105s
", + "bbox": [ + 83, + 88, + 885, + 232 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/fd73c5fab5567fc0c86b2c1287b1eed6dd4312257cf85fe755c4f0bd90bbd811.jpg", + "table_caption": [ + "Table 2. L1 Chamfer Distance in mm (lower is better) between reconstructed mesh and GT after ICP. 'RT' denotes trained on our synthetic MVPS dataset. For non-manual methods, the best result is shown in bold, 2nd best as underline. LZ20 & PJ16 involve carefully crafted steps, manual efforts in finding correspondence, and an initial mesh or point cloud." + ], + "table_footnote": [], + "table_body": "
Per-scene optimizationGeneralizable
CategoryManual EffortStandaloneSingle-view PSMVSMVPS
MethodPJ16 [47]LZ20 [34]BKW22 [29]BKC22 [27]BKW23* [28]PS-NeRF [61]PS- Transformer [24]CasMVSNet [21]-RTTransMVSNet [15]-RTOurs
BEAR0.5510.9860.9280.9340.9650.9950.0780.9110.8820.991
BUDDHA0.9400.9360.6870.9260.9930.9830.0660.9190.9630.958
COW0.9180.9900.9370.9860.9870.9860.1400.9140.9410.993
POT20.4840.9850.9090.8890.9910.9910.1010.9010.9640.994
READING0.9050.9750.8100.9710.9750.9610.9610.9800.9780.988
AVERAGE0.7600.9740.8540.9410.9820.9830.2690.9250.9460.985
Recon. Time/object--7 hrs??12 hrs?22s52s105s
", + "bbox": [ + 78, + 299, + 901, + 452 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 3. F-score with L2 distance and 1mm threshold (higher is better) between reconstructed mesh and GT after ICP. -RT' denotes trained on our synthetic MVPS dataset. For non-manual methods, the best result is shown in bold, 2nd best as underline. LZ20 & PJ16 involve carefully crafted steps, manual efforts in finding correspondence, and an initial mesh or point cloud. BKW23* code not available, results from the paper.", + "bbox": [ + 78, + 459, + 892, + 515 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 80, + 539, + 207, + 555 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Dataset. We evaluate our method and conduct ablation study on DiLiGenT-MV [34] dataset, which is the only benchmark dataset for MVPS tasks and widely used by all previous approaches. It contains images of 5 objects with diverse materials captured from 20 views. For each view, the object is illuminated by one of 96 calibrated point light sources at one time, which gives us 96 images with varying lighting conditions.", + "bbox": [ + 78, + 565, + 467, + 686 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Evaluation metrics. We evaluate the quality of recovered meshes using L1 Chamfer distance from PyTorch3D [33,48] and F-score [32] with L2 distance and 1mm threshold distance. The distances in both metrics are computed between the vertices of two meshes and the units are mm.", + "bbox": [ + 78, + 686, + 467, + 762 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Evaluation details. Ground truth meshes and meshes of PJ16 [47] and LZ20 [34] are included in the DiLiGenTMV dataset [34]. We thank the authors of BKW22 [29] and BKC22 [27] for providing us with their reconstructed meshes. For PS-NeRF [61] we use its publicly available mesh extraction code from stage 1 and unscale the extracted mesh to the scale of the ground truth as suggested in the code. The code or reconstructed meshes of BKW23 [28] was not released, so we only include their reported F-score", + "bbox": [ + 78, + 763, + 467, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "on L2 distance in Table 3. To compare with PS-Transformer [24], we get normal maps from their pretrained model and integrate normals into depth maps, followed by a depth fusion step after rescaling all depth maps to the ground truth depth scales. To compare with CasMVSNet [21] and TransMVSNet [15], we consider both the pretrained models on DTU dataset [1] and models retrained on our synthetic dataset, dubbed as CasMVSNet-RT and TransMVSNet-RT. Images from 5 views are used to generate each single-view depth map and all 20 depth maps are fused together for 3D reconstruction. For ours, we take images from 5 views and 10 lightings conditions for each view, along with corresponding light directions, as input to generate single-view depth maps and all 20 depth maps are fused as other methods. Since there is no image showing the bottoms of objects in DiLiGenT-MV [34], following BKW22 [29] and BKC22 [27], we remove points that are located lower than $+5$ on the z-axis from all reconstructed meshes and the ground truth. Similar to most previous approaches [27, 29, 34, 47] we also perform a rigid registration using Iterative Closest Point (ICP) [2, 4, 12, 67] between the ground-truth and each reconstructed mesh for a fair comparison.", + "bbox": [ + 501, + 539, + 890, + 872 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "12530", + "bbox": [ + 480, + 946, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/b7358e50f9cc2649ba1d451cfdc3d4b64676127dd60e31b45c67178b20333f11.jpg", + "image_caption": [ + "Figure 3. Qualitative comparison of our method with existing approaches (red arrows highlight artifacts) and ablation studies." + ], + "image_footnote": [], + "bbox": [ + 91, + 89, + 888, + 643 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/87e65c0db4fe9ab90dc99a499cc3269318b4d346fced512954c093814cbb4675.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodCasMVSNetCasMVSNet-RTOurs(train 1 light/view)Ours(train 3 light/view)
BEAR2.001.471.310.80
BUDDHA1.441.261.261.07
COW2.731.271.060.77
POT21.891.461.070.82
READING1.070.750.770.66
AVERAGE1.831.241.090.82
", + "bbox": [ + 86, + 667, + 459, + 785 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 4. Ablation: Results are improved by retraining CasMVSNet [20] on proposed synthetic dataset (sMVPS). LAFM help in aggregating features across lighting variations, Ours (train 3 light/view) vs Ours (train 1 light/view), and is more accurate than CasMVSNet features, Ours (train 1 light/view) vs CasMVSNet-RT.", + "bbox": [ + 75, + 796, + 468, + 878 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.1. Comparison with existing approaches", + "text_level": 1, + "bbox": [ + 500, + 669, + 823, + 686 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We compare our algorithm with approaches that require per-scene optimization or training and with feed-forward generalizable methods. The quantitative result is shown in Table 2 and 3. We also show visual comparison of meshes from representative methods in Figure 3.", + "bbox": [ + 496, + 698, + 890, + 773 + ], + "page_idx": 6 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "(i) Per-scene Optimization. Per-Scene optimization methods can also be categorized into:", + "(a) Manual Efforts Needed. We compare with two traditional multi-stage MVPS methods, PJ16 [47] and LZ20 [34], which require manual efforts. We outperform PJ16 [47] with a clear margin. Although LZ20 [34] achieves better results than ours, note that both methods, PJ16 & LZ20, consist of multiple steps with carefully crafted geo-" + ], + "bbox": [ + 496, + 780, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "12531", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "metric modeling. Besides, they require an initial mesh [47] or point cloud [34] to build upon and their performance is sensitive to the initialization quality. When the initialization step fails in large textureless regions, LZ20 [34] incorporates manual labeling to establish correspondence across views. In contrast, our pipeline is completely automatic without any manual efforts, does not involve any carefully crafted multi-stage approach, and does not require separate hyper-parameters for individual object.", + "bbox": [ + 75, + 90, + 472, + 227 + ], + "page_idx": 7 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "(b) Standalone Methods. Recent deep learning-based MVPS methods, including BKW22 [27], BKC22 [29], BKW23 [28] and PS-NeRF [61], are simpler and easier to adopt. However, like traditional methods [34, 47], they still optimize one model for each object individually, resulting in low computational efficiency. In contrast, although our model is trained only on synthetic data, we outperform some per-scene optimized methods [27, 29] and get comparable results as state-of-the-art, PS-NeRF [61]. Furthermore, even though PS-NeRF [61] recovers high-quality meshes with details, its recovered surfaces contain iso-contour pattern artifacts, e.g. see the red arrows in Fig. 3 on BUDDHA and COW, and sometimes incorrect shapes, e.g. READING. Note that, we could not report L1 Chamfer distance on BKW23 [28], since the code is unavailable, but we show in Table 3 that our method is slightly better than BKW23 on F-score.", + "(ii) Generalizable. We compare our method with two categories of generalizable methods:", + "(a) Single-view Photometric Stereo. PS-Transformer [24] is a state-of-the-art PS network, which takes multiple images with the same viewpoint but different lighting conditions as input and generates single-view normal map prediction. To get 3D reconstruction, we integrate each normal map into a depth map and fuse them together. Since the integrated depths are of arbitrary scale, we rescale them to the range of ground truth depth. Inherently, PS methods struggle with global shape modeling and it is challenging to stitch multi-view integrated depth of arbitrary scale, so PS-Transformer [24] doesn't perform well on full-view recovery.", + "(b) Multi-view Stereo. We also compare our method with CasMVSNet [21] and TransMVSNet [15], both of which use a single lighting image from each view. For fairness, we retrain both methods using our synthetic dataset with suggested hyper-parameters in original papers. We observe that lighting information can largely improve both accuracy and quality, quantitatively and qualitatively. On textureless objects, e.g. BEAR, and textureless regions, e.g. belly of BUDDHA, MVS alone gets noisy and rough surfaces. Moreover, our meshes have more high-frequency details that MVS alone may struggle with, e.g. the texture on POT2. This is because our LAFM are supervised with normal maps so they can learn the high-frequency components." + ], + "bbox": [ + 75, + 229, + 472, + 901 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.2. Computational efficiency", + "text_level": 1, + "bbox": [ + 500, + 90, + 728, + 107 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "While our method outperforms some per-scene optimized methods [27, 29] and produces comparable results to state-of-the-arts [28, 61], the key advantage of our method is that it is fast, generalizable, and computationally efficient. Thus we analyze the inference time of the MVPS algorithms compared in this paper to the best of our abilities.", + "bbox": [ + 496, + 113, + 890, + 204 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "- LZ20 [34]: This algorithm takes 117 minutes per object, without considering the time required for initializing a point cloud or any manual efforts. - BKW22 [29]: takes 7 hours to train per object. - BKC22 [27], BKW23 [28]: Since the authors did not mention the time required for training these algorithms it is not possible to provide an exact estimate. However, these approaches are based on MLPs, which take hours to train. - PS-NeRF [61]: takes 12 hours to train per object. - CasMVSNet [20]:, in contrast, takes only 22 seconds per object, including obtaining depth maps for each view using 5 views (1 reference view and 4 source views) and 1 lighting per view (5 images processed for estimating a depth map), fusing depth maps from all 20 views to a point cloud, computing normals for vertices in the point cloud and adopting Screened Poisson [31] to recover a mesh from the point cloud. - MVPSNet (Ours): takes a total of 105 seconds to create a mesh, including steps of obtaining depth maps for each view using 5 views (1 reference view and 4 source views) and 10 lightings per view (50 images processed in total), fusing depth maps from all 20 views to a point cloud, and adopting Screened Poisson [31] to recover a mesh from the point cloud.", + "bbox": [ + 496, + 205, + 892, + 535 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In summary, we are around $240\\times$ faster than BKW22 [29] and around $411.4\\times$ faster than PS-NeRF [61] ignoring their mesh extraction time.", + "bbox": [ + 498, + 536, + 890, + 580 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.3. Ablation study", + "text_level": 1, + "bbox": [ + 500, + 590, + 648, + 606 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "The key contribution of this work includes: (a) our synthetic sMVPS dataset, including sMVPS-sculpture and sMVPS-random, and (b) 'Light Augmented Feature Maps' (LAFM) for more accurate mesh reconstruction. Here we design experiments to analyze impacts of these contributions.", + "bbox": [ + 496, + 613, + 890, + 702 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Synthetic Data (sMVPS-sculpture and sMVPS-random). To illustrate the effectiveness of our synthetic data, we evaluate the performance of a CasMVSNet [21] model trained on DTU dataset [1], and compare it with the CasMVSNet-RT model trained on our sMVPS dataset. The L1 Chamfer distance metric is reported in Table 4. We observe that training on our synthetic dataset improves reconstruction quality by $32.2\\%$ , proving the effectiveness of our proposed data for MVPS reconstructions. See supplementary materials for comparison between pretrained TransMVSNet [15] and TransMVSNet-RT trained on our synthetic dataset.", + "bbox": [ + 496, + 704, + 890, + 883 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Light Augmented Feature Maps (LAFM). LAFM play", + "bbox": [ + 517, + 885, + 890, + 901 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "12532", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/20b838ee429b093a37875e55078ba8c08657b2e5d3042307c9cd13ac78222d0d.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
# of lightings141020304096
3 viewpoints1.2370.8830.8550.8630.8650.8710.892
5 viewpoints1.2440.8560.8230.8310.8400.8470.878
", + "bbox": [ + 91, + 89, + 455, + 135 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 5. Averaged Chamfer-L1 distance (mm) of DiLiGenT-MV. The network is trained with 3 views and 3 lightings per view.", + "bbox": [ + 76, + 143, + 468, + 174 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "two key roles in our approach: (i) they aggregate features from images captured with multiple lighting conditions but the same viewpoints, and (ii) they are trained with surface normal loss which helps to preserve high-frequency details in the features. The predicted surface normals are used to further refine the reconstructed mesh.", + "bbox": [ + 75, + 198, + 468, + 287 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "For understanding the impact of (i), we train our proposed MVPSNet with just a single lighting image per view instead of 3 lightings. Thus LAFM are only aggregated across 1 image per view. In Table 4 we observe that using a single lighting per view ('Ours (train 1 light/view)') produces worse results (1.09 vs 0.82) than using 3 lightings per view ('Ours (train 3 light/view)'). However, even using a single lighting per view produces better performance than CasMVSNet-RT (1.09 vs 1.24), which is also trained on single lighting per view. This shows that LAFM are effective in both extracting accurate information from just a single image and aggregating shading information across multiple images with varying illumination.", + "bbox": [ + 75, + 289, + 468, + 486 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "For understanding the impact of (ii), we train our proposed MVPSNet without any surface normal loss, 'Ours (w/o normal loss). We observe 'Ours (w/o normal loss)' is quantitatively comparable to 'Ours (w/normal loss)', 0.79 vs 0.82 in L1 chamfer distance and 0.985 vs 0.985 in F-score. However, in Fig. 3 we observe that the meshes produced by 'Ours (w/o normal loss)' are significantly noisier as shown with red arrows.", + "bbox": [ + 75, + 486, + 468, + 608 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "4.4. Effects on different numbers of viewpoints and lighting conditions", + "text_level": 1, + "bbox": [ + 76, + 617, + 468, + 648 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We also test the effects of the number of viewpoints and the number of lighting conditions used at inference time. The results of different combinations are shown in Table 5. We target at using sparse views to estimate depth maps, so we only test on 3 and 5 views. The results prove that although trained on 3 views, our model is able to utilize the extra information provided more views. For lighting conditions, the result gets better initially as images under more lighting conditions are provided, but then it gets slightly worse after around 10 lighting conditions.", + "bbox": [ + 75, + 655, + 468, + 806 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "4.5. Result on real-world captures", + "text_level": 1, + "bbox": [ + 76, + 816, + 341, + 834 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We include the result on real-world captures using a simple at-home setup, which requires no special equipment. As shown in Fig 4, a user captures MVPS imagery by attaching a flashlight with a string to the tripod to move lights in", + "bbox": [ + 75, + 839, + 468, + 902 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "a circle around the camera. In our example, images from 5 viewpoints with 3 lighting conditions per view are captured.", + "bbox": [ + 498, + 90, + 890, + 121 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We automatically calibrate camera and lighting conditions using COLMAP [49, 50] and SDPSNet [8] separately. The room isn't strictly dark and contains some ambient lighting. We generate the foreground mask with an off-the-shelf segmentation algorithm. The result shows that our method produces good reconstruction and improves over CasMVSNet [20] in both details and global shapes.", + "bbox": [ + 496, + 123, + 893, + 229 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/3a5134a584e674b95ae10235d0e4b0643041cebbba543b386fa6e85cc526151c.jpg", + "image_caption": [ + "Figure 4. Results of uncalibrated in-the-wild MVPS captures." + ], + "image_footnote": [], + "bbox": [ + 529, + 244, + 717, + 421 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/abd62f8bb1edf6326e63237a3027ca5e728cec033b55a24dcec58a9573654d80.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 718, + 244, + 864, + 421 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 473, + 619, + 489 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this work, we propose a fast and generalizable approach for MVPS. We introduce Light Aggregated Feature Maps that leverage shading cues from images with the same view under multiple lighting conditions to produce richer features in textureless regions. Being trained with normal estimation, LAFM also enable higher quality reconstruction than traditional MVS methods with only little compromise to speed. When trained on the synthetic sMVPS dataset we propose, our method produces results comparable to SOTA method that is about 400x slower at inference time.", + "bbox": [ + 496, + 500, + 890, + 650 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 500, + 670, + 596, + 686 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Henrik Aanæs, Rasmus Ramsbøl Jensen, George Vogiatzis, Engin Tola, and Anders Bjorholm Dahl. Large-scale data for multiple-view stereopsis. International Journal of Computer Vision, 120:153-168, 2016.", + "[2] K. S. Arun, T. S. Huang, and S. D. Blostein. Least-squares fitting of two 3-d point sets. IEEE Transactions on Pattern Analysis and Machine Intelligence, PAMI-9(5):698-700, 1987.", + "[3] Meghna Asthana, William AP Smith, and Patrik Huber. Neural apparent brdf fields for multiview photometric stereo. arXiv preprint arXiv:2207.06793, 2022.", + "[4] Paul J Besl and Neil D McKay. Method for registration of 3-d shapes. In Sensor fusion IV: control paradigms and data structures, volume 1611, pages 586-606. Spie, 1992." + ], + "bbox": [ + 506, + 696, + 893, + 901 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "12533", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[5] Michael Bleyer, Christoph Rhemann, and Carsten Rother. Patchmatch stereo-stereo matching with slanted support windows. In *Bmvc*, volume 11, pages 1-11, 2011.", + "[6] Mark Boss, Varun Jampani, Kihwan Kim, Hendrik P.A. Lensch, and Jan Kautz. Two-shot spatially-varying brdf and shape estimation. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2020.", + "[7] Chenjie Cao, Xinlin Ren, and Yanwei Fu. Mvsformer: Learning robust image representations via transformers and temperature-based depth for multi-view stereo. arXiv preprint arXiv:2208.02541, 2022.", + "[8] Guanying Chen, Kai Han, Boxin Shi, Yasuyuki Matsushita, and Kwan-Yee K Wong. Self-calibrating deep photometric stereo networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 8739-8747, 2019.", + "[9] Guanying Chen, Kai Han, Boxin Shi, Yasuyuki Matsushita, and Kwan-Yee Kenneth Wong. Deep photometric stereo for non-lambertian surfaces. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020.", + "[10] Guanying Chen, Kai Han, and Kwan-Yee K Wong. Ps-fcn: A flexible learning framework for photometric stereo. In Proceedings of the European Conference on Computer Vision (ECCV), pages 3-18, 2018.", + "[11] Guanying Chen, Michael Waechter, Boxin Shi, Kwan-Yee K Wong, and Yasuyuki Matsushita. What is learned in deep uncalibrated photometric stereo? In European Conference on Computer Vision, 2020.", + "[12] Yang Chen and Gérard Medioni. Object modelling by registration of multiple range images. Image and vision computing, 10(3):145-155, 1992.", + "[13] Robert T Collins. A space-sweep approach to true multi-image matching. In Proceedings CVPR IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 358-363. IEEE, 1996.", + "[14] Yikang Ding, Wentao Yuan, Qingtian Zhu, Haotian Zhang, Xiangyue Liu, Yuanjiang Wang, and Xiao Liu. Transmvsnet: Global context-aware multi-view stereo network with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8585-8594, 2022.", + "[15] Yikang Ding, Wentao Yuan, Qingtian Zhu, Haotian Zhang, Xiangyue Liu, Yuanjiang Wang, and Xiao Liu. Transmvsnet: Global context-aware multi-view stereo network with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8585-8594, 2022.", + "[16] Yasutaka Furukawa, Brian Curless, Steven M Seitz, and Richard Szeliski. Towards internet-scale multi-view stereo. In 2010 IEEE computer society conference on computer vision and pattern recognition, pages 1434-1441. IEEE, 2010.", + "[17] Yasutaka Furukawa and Jean Ponce. Accurate, dense, and robust multiview stereopsis. IEEE transactions on pattern analysis and machine intelligence, 32(8):1362-1376, 2009.", + "[18] Khang Truong Giang, Soohwan Song, and Sungho Jo. Curvature-guided dynamic scale networks for multi-view stereo. arXiv preprint arXiv:2112.05999, 2021." + ], + "bbox": [ + 78, + 90, + 467, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[19] Michael Goesele, Noah Snavely, Brian Curless, Hugues Hoppe, and Steven M Seitz. Multi-view stereo for community photo collections. In 2007 IEEE 11th International Conference on Computer Vision, pages 1-8. IEEE, 2007.", + "[20] Xiaodong Gu, Zhiwen Fan, Siyu Zhu, Zuozhuo Dai, Feitong Tan, and Ping Tan. Cascade cost volume for high-resolution multi-view stereo and stereo matching. 2019.", + "[21] Xiaodong Gu, Zhiwen Fan, Siyu Zhu, Zuozhuo Dai, Feitong Tan, and Ping Tan. Cascade cost volume for high-resolution multi-view stereo and stereo matching. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2495-2504, 2020.", + "[22] Carlos Hernandez, George Vogiatzis, and Roberto Cipolla. Multiview photometric stereo. IEEE Transactions on Pattern Analysis and Machine Intelligence, 30(3):548-554, 2008.", + "[23] Po-Han Huang, Kevin Matzen, Johannes Kopf, Narendra Ahuja, and Jia-Bin Huang. Deepmvs: Learning multi-view stereopsis. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 2821-2830, 2018.", + "[24] Satoshi Ikehata. Ps-transformer: Learning sparse photometric stereo network using self-attention mechanism. arXiv preprint arXiv:2211.11386, 2022.", + "[25] Mengqi Ji, Juergen Gall, Haitian Zheng, Yebin Liu, and Lu Fang. Surfacenet: An end-to-end 3d neural network for multiview stereopsis. In Proceedings of the IEEE International Conference on Computer Vision, pages 2307-2315, 2017.", + "[26] Sing Bing Kang, Richard Szeliski, and Jinxiang Chai. Handling occlusions in dense multi-view stereo. In Proceedings of the 2001 IEEE Computer Society Conference on Computer Vision and Pattern Recognition. CVPR 2001, volume 1, pages I-I. IEEE, 2001.", + "[27] Berk Kaya, Suryansh Kumar, Carlos Oliveira, Vittorio Ferrari, and Luc Van Gool. Uncertainty-aware deep multi-view photometric stereo. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12601-12611, 2022.", + "[28] Berk Kaya, Suryansh Kumar, Carlos Oliveira, Vittorio Ferrari, and Luc Van Gool. Multi-view photometric stereo revisited. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 3126-3135, 2023.", + "[29] Berk Kaya, Suryansh Kumar, Francesco Sarno, Vittorio Ferrari, and Luc Van Gool. Neural radiance fields approach to deep multi-view photometric stereo. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1965-1977, 2022.", + "[30] Michael Kazhdan, Matthew Bolitho, and Hugues Hoppe. Poisson surface reconstruction. In Proceedings of the fourth Eurographics symposium on Geometry processing, volume 7, page 0, 2006.", + "[31] Michael Kazhdan and Hugues Hoppe. Screened poisson surface reconstruction. ACM Transactions on Graphics (ToG), 32(3):1-13, 2013.", + "[32] Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: Benchmarking large-scale scene reconstruction. ACM Transactions on Graphics (ToG), 36(4):1-13, 2017." + ], + "bbox": [ + 501, + 92, + 890, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "12534", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[33] Christoph Lassner and Michael Zollhöfer. Pulsar: Efficient sphere-based neural rendering. arXiv:2004.07484, 2020.", + "[34] Min Li, Zhenglong Zhou, Zhe Wu, Boxin Shi, Changyu Diao, and Ping Tan. Multi-view photometric stereo: A robust solution and benchmark dataset for spatially varying isotropic materials. IEEE Transactions on Image Processing, 29:4159-4173, 2020.", + "[35] Zhengqin Li, Zexiang Xu, Ravi Ramamoorthi, Kalyan Sunkavalli, and Manmohan Chandraker. Learning to reconstruct shape and spatially-varying reflectance from a single image. In SIGGRAPH Asia 2018 Technical Papers, page 269. ACM, 2018.", + "[36] Daniel Lichy, Soumyadip Sengupta, and David W Jacobs. Fast light-weight near-field photometric stereo. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12612-12621, 2022.", + "[37] Daniel Lichy, Soumyadip Sengupta, and David W. Jacobs. Fast light-weight near-field photometric stereo. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 12612-12621, June 2022.", + "[38] Daniel Lichy, Jiaye Wu, Soumyadip Sengupta, and David W. Jacobs. Shape and material capture at home. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 6123-6133, June 2021.", + "[39] Daniel Lichy, Jiaye Wu, Soumyadip Sengupta, and David W Jacobs. Shape and material capture at home. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6123-6133, 2021.", + "[40] William E Lorensen and Harvey E Cline. Marching cubes: A high resolution 3d surface construction algorithm. ACM siggraph computer graphics, 21(4):163-169, 1987.", + "[41] Keyang Luo, Tao Guan, Lili Ju, Haipeng Huang, and Yawei Luo. P-mvsnet: Learning patch-wise matching confidence aggregation for multi-view stereo. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10452-10461, 2019.", + "[42] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3d reconstruction in function space. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 4460-4470, 2019.", + "[43] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021.", + "[44] Diego Nehab, Szymon Rusinkiewicz, James Davis, and Ravi Ramamoorthi. Efficiently combining positions and normals for precise 3d geometry. ACM transactions on graphics (TOG), 24(3):536-543, 2005.", + "[45] Michael Oechsle, Songyou Peng, and Andreas Geiger. Unisurf: Unifying neural implicit surfaces and radiance fields for multi-view reconstruction. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 5589-5599, 2021.", + "[46] Jaesik Park, Sudipta N Sinha, Yasuyuki Matsushita, Yu-Wing Tai, and In So Kweon. Multiview photometric stereo" + ], + "bbox": [ + 78, + 90, + 468, + 900 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "using planar mesh parameterization. In Proceedings of the IEEE International Conference on Computer Vision, pages 1161-1168, 2013.", + "[47] Jaesik Park, Sudipta N Sinha, Yasuyuki Matsushita, Yu-Wing Tai, and In So Kweon. Robust multiview photometric stereo using planar mesh parameterization. IEEE transactions on pattern analysis and machine intelligence, 39(8):1591-1604, 2016.", + "[48] Nikhila Ravi, Jeremy Reizenstein, David Novotny, Taylor Gordon, Wan-Yen Lo, Justin Johnson, and Georgia Gkioxari. Accelerating 3d deep learning with pytorch3d. arXiv:2007.08501, 2020.", + "[49] Johannes L Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4104-4113, 2016.", + "[50] Johannes L Schonberger, Enliang Zheng, Jan-Michael Frahm, and Marc Pollefeys. Pixelwise view selection for unstructured multi-view stereo. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part III 14, pages 501-518. Springer, 2016.", + "[51] Soumyadip Sengupta, Angjoo Kanazawa, Carlos D Castillo, and David W Jacobs. Sfsnet: Learning shape, reflectance and illuminance of facesin the wild'. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 6296-6305, 2018.", + "[52] Boxin Shi, Zhe Wu Mo, Dinglong Duan, Sai-Kit Yeung, and Ping Tan. A benchmark dataset and evaluation for non-lambertian and uncalibrated photometric stereo. IEEE Trans. on Pattern Analysis and Machine Intelligence (TPAMI), 41(2):271-284, 2019.", + "[53] Pratul P Srinivasan, Boyang Deng, Xiuming Zhang, Matthew Tancik, Ben Mildenhall, and Jonathan T Barron. Nerv: Neural reflectance and visibility fields for relighting and view synthesis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7495-7504, 2021.", + "[54] Christoph Strecha, Rik Fransens, and Luc Van Gool. Wide-baseline stereo from multiple views: a probabilistic account. In Proceedings of the 2004 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 2004. CVPR 2004., volume 1, pages I-I. IEEE, 2004.", + "[55] Christoph Strecha, Rik Fransens, and Luc Van Gool. Combined depth and outlier estimation in multi-view stereo. In 2006 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'06), volume 2, pages 2394-2401. IEEE, 2006.", + "[56] Jiaming Sun, Yiming Xie, Linghao Chen, Xiaowei Zhou, and Hujun Bao. NeuralRecon: Real-time coherent 3D reconstruction from monocular video. CVPR, 2021.", + "[57] Olivia Wiles and Andrew Zisserman. Silnet: Single- and multi-view reconstruction by learning from silhouettes. In British Machine Vision Conference 2017, BMVC 2017, London, UK, September 4-7, 2017. BMVA Press, 2017.", + "[58] Robert J Woodham. Photometric method for determining surface orientation from multiple images. Optical engineering, 19(1):139-144, 1980." + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "12535", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[59] Qingshan Xu and Wenbing Tao. Learning inverse depth regression for multi-view stereo with correlation cost volume. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 12508-12515, 2020.", + "[60] Zexiang Xu, Kalyan Sunkavalli, Sunil Hadap, and Ravi Ramamoorthi. Deep image-based relighting from optimal sparse samples. ACM Transactions on Graphics (TOG), 37(4):126, 2018.", + "[61] Wenqi Yang, Guanying Chen, Chaofeng Chen, Zhenfang Chen, and Kwan-Yee K Wong. Ps-nerf: Neural inverse rendering for multi-view photometric stereo. arXiv preprint arXiv:2207.11406, 2022.", + "[62] Yao Yao, Zixin Luo, Shiwei Li, Tian Fang, and Long Quan. Mvsnet: Depth inference for unstructured multi-view stereo. In Proceedings of the European conference on computer vision (ECCV), pages 767-783, 2018.", + "[63] Yao Yao, Zixin Luo, Shiwei Li, Tianwei Shen, Tian Fang, and Long Quan. Recurrent mvvsnet for high-resolution multiview stereo depth inference. Computer Vision and Pattern Recognition (CVPR), 2019.", + "[64] Lior Yariv, Yoni Kasten, Dror Moran, Meirav Galun, Matan Atzmon, Basri Ronen, and Yaron Lipman. Multiview neural surface reconstruction by disentangling geometry and appearance. Advances in Neural Information Processing Systems, 33:2492-2502, 2020.", + "[65] Kai Zhang, Fujun Luan, Qianqian Wang, Kavita Bala, and Noah Snavely. Physg: Inverse rendering with spherical gaussians for physics-based material editing and relighting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5453-5462, 2021.", + "[66] Xiuming Zhang, Pratul P Srinivasan, Boyang Deng, Paul Debevec, William T Freeman, and Jonathan T Barron. Nerfactor: Neural factorization of shape and reflectance under an unknown illumination. ACM Transactions on Graphics (TOG), 40(6):1-18, 2021.", + "[67] Zhengyou Zhang. Iterative point matching for registration of free-form curves and surfaces. International journal of computer vision, 13(2):119-152, 1994.", + "[68] Zhenglong Zhou, Zhe Wu, and Ping Tan. Multi-view photometric stereo with spatially varying isotropic materials. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1482-1489, 2013." + ], + "bbox": [ + 78, + 90, + 468, + 684 + ], + "page_idx": 11 + }, + { + "type": "page_number", + "text": "12536", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 11 + } +] \ No newline at end of file diff --git a/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/0b36b82c-cf6a-406b-8b06-65bc02693944_model.json b/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/0b36b82c-cf6a-406b-8b06-65bc02693944_model.json new file mode 100644 index 0000000000000000000000000000000000000000..a5a8b6cc485862e22c35423ec9e5aba64fbd92d7 --- /dev/null +++ b/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/0b36b82c-cf6a-406b-8b06-65bc02693944_model.json @@ -0,0 +1,2556 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.807, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.174, + 0.131, + 0.798, + 0.152 + ], + "angle": 0, + "content": "MVPSNet: Fast Generalizable Multi-view Photometric Stereo" + }, + { + "type": "text", + "bbox": [ + 0.085, + 0.193, + 0.882, + 0.213 + ], + "angle": 0, + "content": "Dongxu Zhao\\(^{1}\\) Daniel Lichy\\(^{2}\\) Pierre-Nicolas Perrin\\(^{1}\\) Jan-Michael Frahm\\(^{1}\\) Soumyadip Sengupta\\(^{1}\\)" + }, + { + "type": "text", + "bbox": [ + 0.145, + 0.223, + 0.825, + 0.242 + ], + "angle": 0, + "content": "1University of North Carolina at Chapel Hill 2University of Maryland, College Park" + }, + { + "type": "text", + "bbox": [ + 0.205, + 0.244, + 0.765, + 0.26 + ], + "angle": 0, + "content": "{dongxuzl, pnperrin, jmf, ronisen}@cs.unc.edu dlichy@umd.edu" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.305, + 0.314, + 0.321 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.337, + 0.473, + 0.578 + ], + "angle": 0, + "content": "We propose a fast and generalizable solution to Multiview Photometric Stereo (MVPS), called MVPSNet. The key to our approach is a feature extraction network that effectively combines images from the same view captured under multiple lighting conditions to extract geometric features from shading cues for stereo matching. We demonstrate these features, termed 'Light Aggregated Feature Maps' (LAFM), are effective for feature matching even in textureless regions, where traditional multi-view stereo methods often fail. Our method produces similar reconstruction results to PS-NeRF, a state-of-the-art MVPS method that optimizes a neural network per-scene, while being \\(411 \\times\\) faster (105 seconds vs. 12 hours) in inference. Additionally, we introduce a new synthetic dataset for MVPS, sMVPS, which is shown to be effective for training a generalizable MVPS method." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.604, + 0.21, + 0.62 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.629, + 0.47, + 0.856 + ], + "angle": 0, + "content": "3D reconstruction of an object can be achieved either through camera viewpoint variations, Multi-view Stereo (MVS), or by lighting direction variations, Photometric Stereo (PS). Both MVS and PS have relative strengths and weaknesses. While MVS succeeds in obtaining accurate global shapes, it suffers in textureless regions due to poor feature matching, often resulting in reconstructions that lack local details. On the other hand, PS produces accurate local details, even in textureless regions, by using shading information but fails to reconstruct accurate global shapes. In this paper, we focus on the problem of Multi-view Photometric Stereo (MVPS) where both camera viewpoint and lighting direction variations are used to accurately reconstruct global and local details of a 3D shape, even in textureless regions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.47, + 0.902 + ], + "angle": 0, + "content": "3D reconstruction techniques that produce high-quality results using only viewpoint variations (MVS) rely on test-time optimization, often by training neural networks per" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.305, + 0.895, + 0.547 + ], + "angle": 0, + "content": "scene [53, 64, 66]. These methods are computationally inefficient, typically taking hours of computing time on a high-end GPU for each object. Existing MVs methods [20, 56, 62] that focus on computational efficiency employ feed-forward neural networks that are efficient but fail to produce high-quality details, especially in textureless regions. Existing MVPS approaches can produce high-quality reconstructions but require computationally inefficient per-scene training or optimization [27, 28, 29, 61]. Sometimes additional manual efforts and carefully crafted refinement steps are also needed [34, 47]. In contrast, we propose an efficient feed-forward neural architecture, MVPSNet, that can generalize to unseen objects and achieve similar reconstruction quality to that of per-scene optimization techniques while being computationally efficient during inference." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.55, + 0.895, + 0.732 + ], + "angle": 0, + "content": "We design MVPSNet by taking inspiration from various deep MVS architectures [7, 14, 18, 20, 62] that are generalizable, computationally efficient, and can operate on high-resolution images. However, these approaches often fail in textureless regions, and their reconstructed meshes often lack details. We choose the CasMVsNet [20] architecture as our feature matching module, which has been repeatedly used by various MVS pipelines [7, 14, 18] for its simplicity and efficiency, and augment it to effectively incorporate lighting variation cues for better prediction of 3D shapes. In this way, we propose a feed-forward generalizable approach to Multi-view Photometric Stereo." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.897, + 0.903 + ], + "angle": 0, + "content": "We introduce a multi-scale feature representation, called Light Aggregated Feature Maps (LAFM), whose role is to extract detailed geometric features from images by utilizing lighting variations. For brevity, we define Multi-light Images as a collection of images taken from the same viewpoint under different directional lighting conditions. Our intuition is that LAFM can efficiently aggregate shading patterns from multi-light images, by creating an 'artificial shading texture' in the textureless region. Multi-scale LAFM will then be used to construct a sequence of cost volumes to match features across sparse views in order to" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "12525" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.182 + ], + "angle": 0, + "content": "predict a depth map for a reference view. We also predict surface normals from LAFM for each viewpoint, enabling LAFM to capture features related to high-frequency local details. The predicted surface normal can be used in addition to the depth maps to produce a more detailed mesh than using the depth maps alone." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.183, + 0.471, + 0.394 + ], + "angle": 0, + "content": "To train the proposed MVPSNet architecture, we introduce a new synthetic MVPS dataset, sMVPS dataset. It consists of shapes from sculpture dataset [57] and random compositions of primitive shapes generated by [60]. We render these shapes with spatially varying Cook-Torrance BRDF under different camera viewpoints and lighting directions. We train MVPSNet on these rendered images with ground-truth supervision over predicted depth and surface normal maps. The trained model generalizes to real-world test scenes from DiLiGenT-MV [34] dataset. We show that simply re-training CasMVsNet on our dataset improves reconstruction quality over the pre-trained model on DiLiGenT-MV by \\(32\\%\\), proving the effectiveness of our synthetic MVPS dataset for generalization." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.394, + 0.471, + 0.59 + ], + "angle": 0, + "content": "We evaluate our approach on the only publicly available MVPS benchmark, the DiLiGenT-MV [34] dataset. Compared to the state-of-the-art MVPS technique, PS-NeRF [61], which optimizes a neural network per-scene, our proposed MVPSNet is \\(\\sim 411\\times\\) faster (105 seconds vs 12 hours) while producing similar reconstruction quality (L1 Chamfer distance of 0.82 vs 0.81, F-score on L2 distance of 0.985 vs 0.983). We further show that adding LAFM significantly improves reconstruction quality over CasMVSNet by \\(34\\%\\) in L1 Chamfer distance. We also observe that refining the reconstructed mesh derived from depth maps with predicted surface normals from LAFM improves reconstruction quality as shown in Fig 3." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.59, + 0.47, + 0.756 + ], + "angle": 0, + "content": "In summary, the key contributions of this paper include: - Light Aggregated Feature Maps (LAFM) that can efficiently utilize multi-light images to extract detailed geometric features, especially in textureless regions. The surface normal predicted from LAFM also improves mesh reconstruction quality. - A synthetic MVPS dataset for training generalizable MVPS methods, which also improves Cas-MVSNet by \\(32\\%\\). - A fast and generalizable Multi-view Photometric Stereo pipeline that is \\(411\\times\\) faster while producing similar reconstruction accuracy compared to state-of-the-art per-scene optimization approach [61]." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.77, + 0.216, + 0.787 + ], + "angle": 0, + "content": "2. Related work" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.468, + 0.903 + ], + "angle": 0, + "content": "Multi-view Stereo (MVS). MVS is a 3D reconstruction technique that utilizes multiple images captured from different viewpoints. While various techniques for MVS have been proposed, one commonly used approach that is relevant to our work involves constructing cost volumes similar to Plane Sweeping Algorithm [13] and then predicting per-view depth maps [21, 25, 41, 59, 62, 63] or disparity" + }, + { + "type": "table", + "bbox": [ + 0.51, + 0.089, + 0.885, + 0.175 + ], + "angle": 0, + "content": "
MethodGeneralizableMesh Reconstruction
PJ16 [47]XBase mesh+displacement map
LZ20 [34]X3D points+PSR [30]+Optimization [44]
BKW22 [29]XMLP+Marching Cube [40]
BKC22 [27]XMLP+Marching Cube [40]
PS-NeRF [61]XMLP+MISE [42]
BKW23 [28]XMLP+Marching Cube [40]
Ours✓3D Points+Screened Poisson [31]
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.184, + 0.877, + 0.198 + ], + "angle": 0, + "content": "Table 1. Comparison of our method with prior MVPS methods." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.229, + 0.892, + 0.349 + ], + "angle": 0, + "content": "maps [23]. To create a cost volume, features are matched across neighboring viewpoints, and the quality of the features plays a critical role in the final reconstruction quality. Traditional methods [5, 16, 17, 19, 26, 50, 54, 55] use human-defined or hand-crafted image processing operators to extract feature maps. With recent advances in deep learning, features learned from deep neural networks have been proven to be effective." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.352, + 0.893, + 0.488 + ], + "angle": 0, + "content": "The most relevant previous works are MVSNet [62] and its variations. MVSNet [62] uses homography to warp feature maps and a 3D CNN to regularize cost volumes. CasMVSNet [21] outperforms MVSNet in terms of accuracy and efficiency by building the 3D cost volume in a cascaded manner. TransMVSNet [15] builds upon CasMVSNet and adopts a transformer to consider intra-image and inter-image feature interactions, which further improves the results of CasMVSNet." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.491, + 0.893, + 0.672 + ], + "angle": 0, + "content": "Photometric Stereo (PS). PS (introduced in [58]) uses lighting variation to reconstruct 3D shapes from a single viewpoint (see [52] for surveys). Calibrated PS approaches, like Chen et al. [10], train a neural network to predict surface normals using data with known lightings. Uncalibrated PS approaches [8, 9, 11] first predict the lighting parameters before solving for surface normals. While most PS works use a large number of images for inference, some use fewer [24, 38], or even one image [6, 35, 36, 51] (often called Shape from Shading). PS approaches are mostly based on feed-forward networks that generalize and can produce near real-time inference with low computational cost [37]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.675, + 0.893, + 0.901 + ], + "angle": 0, + "content": "Multi-view Photometric Stereo (MVPS). MVPS was initially proposed in [22] by combining PS with object silhouettes to reconstruct textureless shiny objects with fine details. However, this method only works well for specific parametric BRDF models [27]. Later, Li et al. [34, 68] propose to get iso-depth contours from PS images and sparse 3D points using structure-from-motion, which are propagated to recover a complete 3D shape. Park et al. [46, 47] use a planar mesh parameterization technique to parameterize a coarse mesh from MVS and take advantage of this 2D parameter domain to perform MVPS. Some of these traditional MVPS methods achieve high-quality results, but they require an initial 3D reconstruction and their performance is sensitive to it. Besides, they consist of multiple steps, so careful execution or expert interventions are often needed to" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "12526" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.102, + 0.089, + 0.323, + 0.334 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.324, + 0.089, + 0.568, + 0.334 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.568, + 0.089, + 0.871, + 0.334 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.349, + 0.894, + 0.392 + ], + "angle": 0, + "content": "Figure 1. Overview of our network architecture. (a) Light Informed Feature Extractor (LIFE) produces a multi-scale feature representation; (b) Light Aggregated Feature Maps (LAFM) Extractor aggregates these features across images of varying lighting conditions but same view; and (c) LAFM is used to create cost volumes and predict depth maps, similar to CasMVSNet [21], in addition to normal map." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.416, + 0.47, + 0.462 + ], + "angle": 0, + "content": "get good results [34, 47]. In contrast, our proposed method trains a neural network end-to-end and the inference only requires one feed-forward pass of the trained network." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.478, + 0.473, + 0.901 + ], + "angle": 0, + "content": "Recently, inspired by NeRF [43], various algorithms have been proposed that optimize a neural network perscene for MVPS. Kaya et al. [29] train a deep PS network first and condition the color rendering in NeRF [43] on normals predicted from PS. The reconstructed mesh, however, exhibits multiple artifacts. The authors in [27] propose to train a deep PS network and a deep MVS network extended with uncertainty estimation separately, and use these to fit the SDF represented by an MLP. To further enable reconstruction on anisotropic and glossy objects, Kaya et al. [28] add a neural volume rendering module to the SDF MLP in [27] to better fuse PS and MVS measurements. PS-NeRF [61] solves the task of jointly estimating the geometry, materials and lights. It first regularizes the gradient of a UNISURF [45] with estimated normals from PS, and then uses separate MLPs to explicitly model surface normal, BRDF, lights, and visibility which are optimized based on a shadow-aware differentiable rendering layer. Recent works have also used physically based differentiable rendering either inside a NeRF framework [3] or separately for optimization [65]. While per-scene optimization methods often generate precise reconstruction results, they have to optimize an individual model for each object separately, which is computationally inefficient. Thus, we propose a solution to Multi-view Photometric Stereo training on a new synthetic MVPS dataset, which is generalizable and can achieve similar results as SOTA per-scene optimization methods." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.415, + 0.644, + 0.433 + ], + "angle": 0, + "content": "3. Our approach" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.44, + 0.649, + 0.457 + ], + "angle": 0, + "content": "3.1. Problem setup" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.463, + 0.892, + 0.538 + ], + "angle": 0, + "content": "We focus on the problem of calibrated multi-view photometric stereo, i.e. the locations of the light sources and the cameras are known a priori (calibrated prior to capture). The input data consists of a set of multi-light images of an object captured from multiple views." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.539, + 0.893, + 0.659 + ], + "angle": 0, + "content": "Concretely, for the \\(i\\)-th view we have \\(M_{i}\\) images with varying lighting directions \\(l_{ij}\\), denoted as \\(I_{ij}\\). We refer to the collection \\(\\{I_{i1}, \\dots, I_{iM_i}\\}\\) as the multi-light images for the \\(i\\)-th view. For each view, we are given camera intrinsic matrix \\(K_{i}\\) and camera extrinsic parameters in the form of a rotation matrix, \\(R_{i}\\), and a translation vector, \\(t_i\\). Similar to virtually all MVS methods, we assume that we are provided with the depth range for each view." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.666, + 0.623, + 0.681 + ], + "angle": 0, + "content": "3.2. Motivation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.689, + 0.892, + 0.854 + ], + "angle": 0, + "content": "Our approach follows a long line of work in Multi-view Stereo which uses Plane Sweep to construct a cost volume and predicts a depth map aligned with a reference image. Recent advances in Plane Sweep Stereo using deep neural networks, especially CasMVSNet [21], have proven to be generalizable across scenes and can predict high-resolution reconstruction in a matter of seconds. In contrast to previous Multi-view Photometric Stereo approaches, which optimize a neural network per scene, our goal is to produce a generalizable solution. Thus we aim to build upon the Plane Sweep stereo architecture proposed in CasMVSNet [21]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.893, + 0.901 + ], + "angle": 0, + "content": "CasMVSNet learns a deep image feature encoder for extracting representative features that can aid in feature matching across multiple views and create better cost vol" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "12527" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.168 + ], + "angle": 0, + "content": "umes. However, these features are often ambiguous for non-textured regions and fail to preserve the geometric details. We believe incorporating lighting variations along with viewpoint variations can lead to better features, which in turn will produce better cost volumes and depth maps." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.168, + 0.47, + 0.349 + ], + "angle": 0, + "content": "To this end, we introduce 'Light Aggregated Feature Maps' (LAFM), whose goal is to extract detailed geometric features, even for textureless regions, by jointly learning to aggregate feature maps over all images captured from a single viewpoint and multiple lighting directions. To obtain effective features that capture geometric details we use LAFM to regress surface normals. We show that LAFM provide superior information for stereo-matching than single-lighting feature maps (as used in CasMVSNet) and thus provide a better reconstruction. We also show that surface normals predicted using LAFM can be used during mesh reconstruction to improve quality over depth maps alone." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.35, + 0.471, + 0.593 + ], + "angle": 0, + "content": "Our approach proceeds in three stages. We first extract multi-scale feature representation from each image, along with its lighting directions, using a shared neural network, 'Light Informed Feature Extractor' (LIFE). To aggregate features extracted by LIFE across all images under the same viewpoint but different lighting conditions, we use max-pooling operation. We can then create a cost volume for the reference view by matching LAFM of the reference view with all the LAFM from neighboring views. Finally, for each reference view, we predict a depth map using cost volume regularization and a surface normal map from the LAFM. We train our system in a multi-task learning framework with supervised losses over depth and normal predictions. In the following sections, we provide the details of our MVPSNet pipeline. An overview of MVPSNet architecture is illustrated in Figure 1." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.604, + 0.429, + 0.621 + ], + "angle": 0, + "content": "3.3. Light Aggregated Feature Maps (LAFM)" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.628, + 0.47, + 0.884 + ], + "angle": 0, + "content": "We introduce Light Aggregated Feature Maps (LAFM) that provide geometrically distinct multi-scale features for cost volume creation in a Plane Sweep Stereo approach. Our key observation is that the multi-light images provide us with important information for feature matching. For textureless regions, the variation in shading (including cast and attached shadows) created by different lighting directions can be interpreted as 'artificial' textures. Thus the role of LAFM for textureless regions is to capture the variation in shading as an 'artificial' texture that can be used for feature matching across different viewpoints. We also use LAFM to predict surface normal maps, enabling it to capture geometric details required for producing high-quality normal maps. Hence LAFM can capture better features for textureless regions and for reconstructing details, which were absent in the usual deep image features used in deep multi-view stereo algorithms." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.886, + 0.468, + 0.901 + ], + "angle": 0, + "content": "We first define a multi-scale feature extractor, Light In" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.198 + ], + "angle": 0, + "content": "formed Feature Extractor (LIFE), that takes an image \\( I_{ij} \\) associated with its lighting direction \\( l_{ij} \\) as input and produces feature maps at three different scales \\( F_{ij}^{1}, F_{ij}^{2}, F_{ij}^{3} \\) at resolutions \\( 1/4, 1/2, 1 \\) of the input resolution, and another feature map \\( NF_{ij} \\) that will be used for normal prediction. The network architecture of LIFE is shown in Fig. 1(a) and will be discussed in details in the supplementary material." + }, + { + "type": "equation", + "bbox": [ + 0.563, + 0.206, + 0.891, + 0.224 + ], + "angle": 0, + "content": "\\[\nN F _ {i j}, F _ {i j} ^ {1}, F _ {i j} ^ {2}, F _ {i j} ^ {3} = L I F E \\left(I _ {i j}, l _ {i j}; \\theta\\right) \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.223, + 0.891, + 0.253 + ], + "angle": 0, + "content": "Note \\(l_{ij}\\) is of the same resolution as \\(I_{ij}\\) by simply repeating the same 3-dimensional lighting vector at each pixel." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.254, + 0.892, + 0.449 + ], + "angle": 0, + "content": "Then we extract these multi-scale features for every image captured under the same viewpoint and different lighting conditions, \\(\\{I_{i1},\\dots,I_{iM_i}\\}\\), using the same shared encoder LIFE. Let the feature maps obtained from these images be denoted as: \\(\\{NF_{ij},F_{ij}^{1},F_{ij}^{2},F_{ij}^{3}\\}\\), \\(j = 1,\\dots,M_i\\). We create 'Light Aggregated Feature Maps' (LAFM) from these multi-scale feature representations by performing a max-pooling operation for each scale. Pooling operations can handle various numbers of input feature maps and are order-agnostic. Moreover, max-pooling helps save the most prominent feature across all views and ignores non-activated features, which automatically handles shadows casted by directional lights [10]." + }, + { + "type": "equation", + "bbox": [ + 0.601, + 0.45, + 0.891, + 0.473 + ], + "angle": 0, + "content": "\\[\nF _ {i} ^ {s} = \\max _ {j} F _ {i j} ^ {s}, \\quad \\forall s = 1, 2, 3 \\tag {2}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.59, + 0.477, + 0.891, + 0.499 + ], + "angle": 0, + "content": "\\[\nN F _ {i} = \\max _ {j} N F _ {i j}. \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.499, + 0.891, + 0.529 + ], + "angle": 0, + "content": "Thus for multi-light images we obtain LAFM as \\(LF_{i} = \\{NF_{i},F_{i}^{1},F_{i}^{2},F_{i}^{3}\\}\\)" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.53, + 0.892, + 0.681 + ], + "angle": 0, + "content": "The features at 3 scales \\( F_{i}^{1}, F_{i}^{2}, F_{i}^{3} \\) are then used to build cost volumes using differentiable homography warping, which we will talk about in detail in Section 3.4. The normal feature \\( NF_{i} \\) is fed into a lightweight normal regression network to predict per-view normal map, as shown in Figure 1(c). With the supervision from normal information and depth information, our LAFM benefit from the advantages of both MVS and PS which are good at global shape modeling and high-frequency component reconstruction, respectively." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.694, + 0.834, + 0.71 + ], + "angle": 0, + "content": "3.4. Cost volume and depth map prediction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.718, + 0.892, + 0.869 + ], + "angle": 0, + "content": "Given Light Aggregated Feature Maps (LAFM), \\(LF_{i}\\) for each view \\(i\\), we aim to build a cost volume for each reference view by selecting a set of source views with sufficient overlap. We adopt the multi-scale cost volume construction proposed in CasMVSNet [21], where the plane sweep is first performed at a low resolution and then at higher resolutions. Depth estimated from the previous step is used for generating depth proposals for the next step. Multi-scale cost volume reconstruction and depth map prediction follow the following steps." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Step 1: Depth hypothesis generation. We generate hypothesis depths for each pixel based on the lower resolution" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "12528" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.12 + ], + "angle": 0, + "content": "depth estimated at the previous resolution. We store these in \\(h\\), where" + }, + { + "type": "equation", + "bbox": [ + 0.091, + 0.12, + 0.469, + 0.149 + ], + "angle": 0, + "content": "\\[\nh (u, v, w) = U p \\left(D ^ {s - 1}\\right) (u, v) + \\Delta_ {s} \\left(\\frac {w}{N _ {s} - 1} - \\frac {1}{2}\\right). \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.148, + 0.469, + 0.223 + ], + "angle": 0, + "content": "Here \\( h(u,v,w) \\) is the \\( w \\)-th depth hypothesis at pixel \\( (u,v) \\). \\( Up(D^{s - 1}) \\) is the depth map at the previous lower resolution upsampled to the current resolution. \\( \\Delta_s \\) is the length of the depth interval we are searching at scale \\( s \\). \\( N_{s} \\) is the number of hypothesis depths at the current scale." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.223, + 0.469, + 0.346 + ], + "angle": 0, + "content": "Step 2: Cost volume construction. Building cost volume is a way of robustly searching for matches between a point \\((u, v)\\) in the reference image \\(I_r\\) and a point on the corresponding epipolar line in the source image \\(I_{s_k}\\). Concretely, consider a pixel \\((u, v)\\) in the reference image. For every hypothesis depth \\(d\\), we get a corresponding point in the source image on the epipolar line for \\((u, v)\\). We denote this point by \\((u', v') = \\mathrm{warp}_{rs_k}(u, v, d)\\) where" + }, + { + "type": "equation", + "bbox": [ + 0.095, + 0.348, + 0.469, + 0.394 + ], + "angle": 0, + "content": "\\[\n\\left[ \\begin{array}{l} u ^ {\\prime} \\\\ v ^ {\\prime} \\\\ 1 \\end{array} \\right] \\sim K _ {s _ {k}} R _ {s _ {k}} ^ {T} \\left[ \\left(R _ {r} K _ {r} ^ {- 1} d \\left[ \\begin{array}{l} u \\\\ v \\\\ 1 \\end{array} \\right] + t _ {r}\\right) - t _ {s} \\right]. \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.398, + 0.357, + 0.412 + ], + "angle": 0, + "content": "We then construct a per-image volume:" + }, + { + "type": "equation", + "bbox": [ + 0.117, + 0.412, + 0.469, + 0.429 + ], + "angle": 0, + "content": "\\[\nF _ {i} \\operatorname {v o l} _ {i} ^ {s} (u, v, w) = F _ {i} ^ {s} \\left(w a r p (u, v, h (u, v, w))\\right), \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.428, + 0.469, + 0.517 + ], + "angle": 0, + "content": "where \\(i\\) runs over the reference and source views i.e. \\(i \\in \\{r, s_1, \\dots, s_k\\}\\). These volumes are then aggregated into a single cost volume by taking their variance, which checks for the photo-consistency of the depth proposal \\(d\\) for pixel \\((u, v)\\) in the reference image and the corresponding pixels in the warped sources images \\(s_k\\):" + }, + { + "type": "equation", + "bbox": [ + 0.136, + 0.518, + 0.469, + 0.534 + ], + "angle": 0, + "content": "\\[\n\\operatorname {a g g} _ {-} \\operatorname {v o l} ^ {s} (u, v, w) = \\operatorname {v a r} _ {i} \\left(\\mathrm {F} _ {-} \\operatorname {v o l} (\\mathrm {u}, \\mathrm {v}, \\mathrm {w}) _ {i} ^ {s}\\right). \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.534, + 0.469, + 0.579 + ], + "angle": 0, + "content": "Step 3: Cost regularization. In this step we pass the aggregated volume through a 3D convolutional network and take a softmax to convert it to a match probability, using" + }, + { + "type": "equation", + "bbox": [ + 0.127, + 0.579, + 0.469, + 0.594 + ], + "angle": 0, + "content": "\\[\n\\operatorname {p r o b} _ {-} \\operatorname {v o l} = \\operatorname {s o f t} _ {-} \\max _ {w} \\left(\\operatorname {r e g} _ {-} \\operatorname {n e t} ^ {s} \\left(\\operatorname {a g g} _ {-} \\operatorname {v o l} ^ {s}\\right)\\right). \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.594, + 0.469, + 0.653 + ], + "angle": 0, + "content": "Step 4: Regression. We take the expectation of the hypothesis depths over the match probability given by the probability volume to obtain the depth at the current scale, which enables sub-pixel estimation." + }, + { + "type": "equation", + "bbox": [ + 0.126, + 0.653, + 0.469, + 0.682 + ], + "angle": 0, + "content": "\\[\nD ^ {s} (u, v) = \\sum_ {w} \\operatorname {p r o b} _ {-} \\operatorname {v o l} (u, v, w) h (u, v, w). \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.682, + 0.421, + 0.696 + ], + "angle": 0, + "content": "This whole process is summarized in algorithm 1" + }, + { + "type": "title", + "bbox": [ + 0.08, + 0.711, + 0.312, + 0.726 + ], + "angle": 0, + "content": "Algorithm 1 MVPSNet Algorithm" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.728, + 0.36, + 0.746 + ], + "angle": 0, + "content": "1: \\(NF_{ij},F_{ij}^{1},F_{ij}^{2},F_{ij}^{3} = \\mathrm{LIFE}(I_{ij},l_{ij};\\theta)\\)" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.746, + 0.448, + 0.761 + ], + "angle": 0, + "content": "2: \\(NF_{i} = \\max_{j}NF_{ij};F_{i}^{s} = \\max_{j}F_{ij}^{s}\\quad \\forall s = 1,2,3.\\)" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.761, + 0.338, + 0.775 + ], + "angle": 0, + "content": "3: \\(N_{i} =\\) normal_regression_net \\((NF_{i})\\)" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.775, + 0.377, + 0.79 + ], + "angle": 0, + "content": "4: \\(D^0 (u,v) = (\\max_{-}\\mathrm{depth} + \\min_{-}\\mathrm{depth}) / 2\\)" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.791, + 0.218, + 0.803 + ], + "angle": 0, + "content": "5: for \\( s = 1 \\) to 3 do" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.804, + 0.443, + 0.822 + ], + "angle": 0, + "content": "6: \\(h(u,v,w) = Up(D^{s - 1})(u,v) + \\Delta_s(\\frac{w}{N_s - 1} -\\frac{1}{2})\\)" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.822, + 0.426, + 0.836 + ], + "angle": 0, + "content": "7: \\(\\mathrm{F\\_vol}_i^s (u,v,w) = F_i^s (warp(u,v,h(u,\\bar{v},w)))\\)" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.836, + 0.341, + 0.851 + ], + "angle": 0, + "content": "8: \\(\\mathrm{agg\\_vol}^s (u,v,w) = \\mathrm{var}_i(\\mathrm{F\\_vol}_i^s)\\)" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.851, + 0.403, + 0.866 + ], + "angle": 0, + "content": "9: prob_vol = soft_max_w(reg_net^s(agg_vol^s))" + }, + { + "type": "ref_text", + "bbox": [ + 0.085, + 0.866, + 0.416, + 0.881 + ], + "angle": 0, + "content": "10: \\(D^{s}(u,v) = \\sum_{w}\\mathrm{prob\\_vol}(u,v,w)h(u,v,w)\\)" + }, + { + "type": "ref_text", + "bbox": [ + 0.084, + 0.882, + 0.16, + 0.894 + ], + "angle": 0, + "content": "11: end for" + }, + { + "type": "list", + "bbox": [ + 0.084, + 0.728, + 0.448, + 0.894 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.507, + 0.09, + 0.867, + 0.214 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.23, + 0.892, + 0.244 + ], + "angle": 0, + "content": "Figure 2. Example images from proposed synthetic MVPS dataset." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.267, + 0.892, + 0.343 + ], + "angle": 0, + "content": "Once we have depth and surface normal for each view, our mesh reconstruction pipeline consists of three steps: depth filtering, lifting depth and normal maps to a point cloud, and reconstructing the mesh using Screened Poisson [31] (See supplementary materials for details)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.351, + 0.724, + 0.367 + ], + "angle": 0, + "content": "3.5. Synthetic MVPS dataset" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.374, + 0.892, + 0.509 + ], + "angle": 0, + "content": "A key component of our method is that we can learn better features for stereo matching, especially in textureless regions, by learning features that incorporate multi-lighting cues. However, there is no existing MVPS dataset that is large enough for neural network training. Therefore, we generate a large-scale synthetic dataset, sMVPS, consisting of two sub-datasets, sMVPS-sculpture (800 train scenes/4 test scenes) and sMVPS-random (1000 train scenes/20 test scenes)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.51, + 0.892, + 0.676 + ], + "angle": 0, + "content": "sMVPS-sculpture consists of objects from the sculpture dataset [57] while sMVPS-random includes objects composed of random primitives from [60]. The objects were generated following the method of [39] with spatially varying Cook-Torrance BRDF. We render images from 20 viewpoints surrounding the object approximately every \\(18^{\\circ}\\) plus random jitter in position. For each view we render 10 randomly chosen directional light sources sampled uniformly on a \\(45^{\\circ}\\) spherical cap centered at the camera's optical axis. In addition to the images, we render ground truth normals, depth, albedo, and roughness." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.684, + 0.687, + 0.7 + ], + "angle": 0, + "content": "3.6. Training MVPSNet" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.707, + 0.892, + 0.782 + ], + "angle": 0, + "content": "We train MVPSNet with supervised loss over surface normal and depth using the ground-truth created within synthetic sMVPS dataset. For each reference view, we use 2 source views. And we randomly choose 3 lights out of 10 to train our model. The total loss is defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.576, + 0.783, + 0.891, + 0.799 + ], + "angle": 0, + "content": "\\[\nL _ {m v p s} = \\lambda_ {d} \\cdot L _ {d} + \\lambda_ {n} \\cdot L _ {n}, \\tag {10}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.601, + 0.803, + 0.891, + 0.843 + ], + "angle": 0, + "content": "\\[\nL _ {d} = \\sum_ {s = 1} ^ {3} \\lambda_ {d s} \\cdot L _ {d s}, \\forall s = 1, 2, 3 \\tag {11}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.841, + 0.892, + 0.9 + ], + "angle": 0, + "content": "where \\(L_{ds}\\) and \\(L_{n}\\) refer to the depth loss for scale \\(s\\) and normal loss, respectively. For loss weights, we set \\(\\lambda_{n} = 1\\) and \\(\\lambda_{d} = 10\\). The weights of each scale, \\(\\lambda_{ds} = 1\\), for \\(s = 1,2,3\\)." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "12529" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.084, + 0.089, + 0.887, + 0.233 + ], + "angle": 0, + "content": "
Per-scene optimizationGeneralizable
CategoryManual EffortStandaloneSingle-view PSMVSMVPS
MethodPJ16 [47]LZ20 [34]BKW22 [29]BKC22 [27]PS-NeRF [61]PS- Transformer [24]CasMVSNet [21]- RTTransMVSNet [15]- RTOurs
BEAR2.540.731.011.010.763.171.471.480.80
BUDDHA1.120.972.681.150.864.091.261.101.07
COW1.140.391.090.760.753.041.271.050.77
POT23.210.671.541.400.763.051.461.050.82
READING1.300.661.970.840.923.600.750.760.66
AVERAGE1.860.691.661.030.813.391.241.090.82
Recon. Time/object--7 hrs?12 hrs?22s52s105s
" + }, + { + "type": "table_caption", + "bbox": [ + 0.08, + 0.243, + 0.893, + 0.285 + ], + "angle": 0, + "content": "Table 2. L1 Chamfer Distance in mm (lower is better) between reconstructed mesh and GT after ICP. 'RT' denotes trained on our synthetic MVPS dataset. For non-manual methods, the best result is shown in bold, 2nd best as underline. LZ20 & PJ16 involve carefully crafted steps, manual efforts in finding correspondence, and an initial mesh or point cloud." + }, + { + "type": "table", + "bbox": [ + 0.08, + 0.3, + 0.902, + 0.453 + ], + "angle": 0, + "content": "
Per-scene optimizationGeneralizable
CategoryManual EffortStandaloneSingle-view PSMVSMVPS
MethodPJ16 [47]LZ20 [34]BKW22 [29]BKC22 [27]BKW23* [28]PS-NeRF [61]PS- Transformer [24]CasMVSNet [21]-RTTransMVSNet [15]-RTOurs
BEAR0.5510.9860.9280.9340.9650.9950.0780.9110.8820.991
BUDDHA0.9400.9360.6870.9260.9930.9830.0660.9190.9630.958
COW0.9180.9900.9370.9860.9870.9860.1400.9140.9410.993
POT20.4840.9850.9090.8890.9910.9910.1010.9010.9640.994
READING0.9050.9750.8100.9710.9750.9610.9610.9800.9780.988
AVERAGE0.7600.9740.8540.9410.9820.9830.2690.9250.9460.985
Recon. Time/object--7 hrs??12 hrs?22s52s105s
" + }, + { + "type": "table_caption", + "bbox": [ + 0.08, + 0.46, + 0.893, + 0.516 + ], + "angle": 0, + "content": "Table 3. F-score with L2 distance and 1mm threshold (higher is better) between reconstructed mesh and GT after ICP. -RT' denotes trained on our synthetic MVPS dataset. For non-manual methods, the best result is shown in bold, 2nd best as underline. LZ20 & PJ16 involve carefully crafted steps, manual efforts in finding correspondence, and an initial mesh or point cloud. BKW23* code not available, results from the paper." + }, + { + "type": "title", + "bbox": [ + 0.081, + 0.54, + 0.208, + 0.556 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.566, + 0.468, + 0.687 + ], + "angle": 0, + "content": "Dataset. We evaluate our method and conduct ablation study on DiLiGenT-MV [34] dataset, which is the only benchmark dataset for MVPS tasks and widely used by all previous approaches. It contains images of 5 objects with diverse materials captured from 20 views. For each view, the object is illuminated by one of 96 calibrated point light sources at one time, which gives us 96 images with varying lighting conditions." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.688, + 0.468, + 0.763 + ], + "angle": 0, + "content": "Evaluation metrics. We evaluate the quality of recovered meshes using L1 Chamfer distance from PyTorch3D [33,48] and F-score [32] with L2 distance and 1mm threshold distance. The distances in both metrics are computed between the vertices of two meshes and the units are mm." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.765, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Evaluation details. Ground truth meshes and meshes of PJ16 [47] and LZ20 [34] are included in the DiLiGenTMV dataset [34]. We thank the authors of BKW22 [29] and BKC22 [27] for providing us with their reconstructed meshes. For PS-NeRF [61] we use its publicly available mesh extraction code from stage 1 and unscale the extracted mesh to the scale of the ground truth as suggested in the code. The code or reconstructed meshes of BKW23 [28] was not released, so we only include their reported F-score" + }, + { + "type": "text", + "bbox": [ + 0.503, + 0.54, + 0.892, + 0.873 + ], + "angle": 0, + "content": "on L2 distance in Table 3. To compare with PS-Transformer [24], we get normal maps from their pretrained model and integrate normals into depth maps, followed by a depth fusion step after rescaling all depth maps to the ground truth depth scales. To compare with CasMVSNet [21] and TransMVSNet [15], we consider both the pretrained models on DTU dataset [1] and models retrained on our synthetic dataset, dubbed as CasMVSNet-RT and TransMVSNet-RT. Images from 5 views are used to generate each single-view depth map and all 20 depth maps are fused together for 3D reconstruction. For ours, we take images from 5 views and 10 lightings conditions for each view, along with corresponding light directions, as input to generate single-view depth maps and all 20 depth maps are fused as other methods. Since there is no image showing the bottoms of objects in DiLiGenT-MV [34], following BKW22 [29] and BKC22 [27], we remove points that are located lower than \\(+5\\) on the z-axis from all reconstructed meshes and the ground truth. Similar to most previous approaches [27, 29, 34, 47] we also perform a rigid registration using Iterative Closest Point (ICP) [2, 4, 12, 67] between the ground-truth and each reconstructed mesh for a fair comparison." + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.947, + 0.518, + 0.957 + ], + "angle": 0, + "content": "12530" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.092, + 0.09, + 0.889, + 0.645 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.114, + 0.651, + 0.855, + 0.665 + ], + "angle": 0, + "content": "Figure 3. Qualitative comparison of our method with existing approaches (red arrows highlight artifacts) and ablation studies." + }, + { + "type": "table", + "bbox": [ + 0.088, + 0.669, + 0.46, + 0.786 + ], + "angle": 0, + "content": "
MethodCasMVSNetCasMVSNet-RTOurs(train 1 light/view)Ours(train 3 light/view)
BEAR2.001.471.310.80
BUDDHA1.441.261.261.07
COW2.731.271.060.77
POT21.891.461.070.82
READING1.070.750.770.66
AVERAGE1.831.241.090.82
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.797, + 0.47, + 0.879 + ], + "angle": 0, + "content": "Table 4. Ablation: Results are improved by retraining CasMVSNet [20] on proposed synthetic dataset (sMVPS). LAFM help in aggregating features across lighting variations, Ours (train 3 light/view) vs Ours (train 1 light/view), and is more accurate than CasMVSNet features, Ours (train 1 light/view) vs CasMVSNet-RT." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.67, + 0.825, + 0.687 + ], + "angle": 0, + "content": "4.1. Comparison with existing approaches" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.699, + 0.892, + 0.775 + ], + "angle": 0, + "content": "We compare our algorithm with approaches that require per-scene optimization or training and with feed-forward generalizable methods. The quantitative result is shown in Table 2 and 3. We also show visual comparison of meshes from representative methods in Figure 3." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.781, + 0.892, + 0.81 + ], + "angle": 0, + "content": "(i) Per-scene Optimization. Per-Scene optimization methods can also be categorized into:" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.892, + 0.901 + ], + "angle": 0, + "content": "(a) Manual Efforts Needed. We compare with two traditional multi-stage MVPS methods, PJ16 [47] and LZ20 [34], which require manual efforts. We outperform PJ16 [47] with a clear margin. Although LZ20 [34] achieves better results than ours, note that both methods, PJ16 & LZ20, consist of multiple steps with carefully crafted geo-" + }, + { + "type": "list", + "bbox": [ + 0.498, + 0.781, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.518, + 0.957 + ], + "angle": 0, + "content": "12531" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.228 + ], + "angle": 0, + "content": "metric modeling. Besides, they require an initial mesh [47] or point cloud [34] to build upon and their performance is sensitive to the initialization quality. When the initialization step fails in large textureless regions, LZ20 [34] incorporates manual labeling to establish correspondence across views. In contrast, our pipeline is completely automatic without any manual efforts, does not involve any carefully crafted multi-stage approach, and does not require separate hyper-parameters for individual object." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.23, + 0.473, + 0.487 + ], + "angle": 0, + "content": "(b) Standalone Methods. Recent deep learning-based MVPS methods, including BKW22 [27], BKC22 [29], BKW23 [28] and PS-NeRF [61], are simpler and easier to adopt. However, like traditional methods [34, 47], they still optimize one model for each object individually, resulting in low computational efficiency. In contrast, although our model is trained only on synthetic data, we outperform some per-scene optimized methods [27, 29] and get comparable results as state-of-the-art, PS-NeRF [61]. Furthermore, even though PS-NeRF [61] recovers high-quality meshes with details, its recovered surfaces contain iso-contour pattern artifacts, e.g. see the red arrows in Fig. 3 on BUDDHA and COW, and sometimes incorrect shapes, e.g. READING. Note that, we could not report L1 Chamfer distance on BKW23 [28], since the code is unavailable, but we show in Table 3 that our method is slightly better than BKW23 on F-score." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.491, + 0.47, + 0.52 + ], + "angle": 0, + "content": "(ii) Generalizable. We compare our method with two categories of generalizable methods:" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.52, + 0.47, + 0.702 + ], + "angle": 0, + "content": "(a) Single-view Photometric Stereo. PS-Transformer [24] is a state-of-the-art PS network, which takes multiple images with the same viewpoint but different lighting conditions as input and generates single-view normal map prediction. To get 3D reconstruction, we integrate each normal map into a depth map and fuse them together. Since the integrated depths are of arbitrary scale, we rescale them to the range of ground truth depth. Inherently, PS methods struggle with global shape modeling and it is challenging to stitch multi-view integrated depth of arbitrary scale, so PS-Transformer [24] doesn't perform well on full-view recovery." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.704, + 0.471, + 0.902 + ], + "angle": 0, + "content": "(b) Multi-view Stereo. We also compare our method with CasMVSNet [21] and TransMVSNet [15], both of which use a single lighting image from each view. For fairness, we retrain both methods using our synthetic dataset with suggested hyper-parameters in original papers. We observe that lighting information can largely improve both accuracy and quality, quantitatively and qualitatively. On textureless objects, e.g. BEAR, and textureless regions, e.g. belly of BUDDHA, MVS alone gets noisy and rough surfaces. Moreover, our meshes have more high-frequency details that MVS alone may struggle with, e.g. the texture on POT2. This is because our LAFM are supervised with normal maps so they can learn the high-frequency components." + }, + { + "type": "list", + "bbox": [ + 0.076, + 0.23, + 0.473, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.091, + 0.729, + 0.108 + ], + "angle": 0, + "content": "4.2. Computational efficiency" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.114, + 0.892, + 0.205 + ], + "angle": 0, + "content": "While our method outperforms some per-scene optimized methods [27, 29] and produces comparable results to state-of-the-arts [28, 61], the key advantage of our method is that it is fast, generalizable, and computationally efficient. Thus we analyze the inference time of the MVPS algorithms compared in this paper to the best of our abilities." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.206, + 0.893, + 0.536 + ], + "angle": 0, + "content": "- LZ20 [34]: This algorithm takes 117 minutes per object, without considering the time required for initializing a point cloud or any manual efforts. - BKW22 [29]: takes 7 hours to train per object. - BKC22 [27], BKW23 [28]: Since the authors did not mention the time required for training these algorithms it is not possible to provide an exact estimate. However, these approaches are based on MLPs, which take hours to train. - PS-NeRF [61]: takes 12 hours to train per object. - CasMVSNet [20]:, in contrast, takes only 22 seconds per object, including obtaining depth maps for each view using 5 views (1 reference view and 4 source views) and 1 lighting per view (5 images processed for estimating a depth map), fusing depth maps from all 20 views to a point cloud, computing normals for vertices in the point cloud and adopting Screened Poisson [31] to recover a mesh from the point cloud. - MVPSNet (Ours): takes a total of 105 seconds to create a mesh, including steps of obtaining depth maps for each view using 5 views (1 reference view and 4 source views) and 10 lightings per view (50 images processed in total), fusing depth maps from all 20 views to a point cloud, and adopting Screened Poisson [31] to recover a mesh from the point cloud." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.537, + 0.892, + 0.582 + ], + "angle": 0, + "content": "In summary, we are around \\(240\\times\\) faster than BKW22 [29] and around \\(411.4\\times\\) faster than PS-NeRF [61] ignoring their mesh extraction time." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.591, + 0.65, + 0.607 + ], + "angle": 0, + "content": "4.3. Ablation study" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.614, + 0.892, + 0.703 + ], + "angle": 0, + "content": "The key contribution of this work includes: (a) our synthetic sMVPS dataset, including sMVPS-sculpture and sMVPS-random, and (b) 'Light Augmented Feature Maps' (LAFM) for more accurate mesh reconstruction. Here we design experiments to analyze impacts of these contributions." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.892, + 0.884 + ], + "angle": 0, + "content": "Synthetic Data (sMVPS-sculpture and sMVPS-random). To illustrate the effectiveness of our synthetic data, we evaluate the performance of a CasMVSNet [21] model trained on DTU dataset [1], and compare it with the CasMVSNet-RT model trained on our sMVPS dataset. The L1 Chamfer distance metric is reported in Table 4. We observe that training on our synthetic dataset improves reconstruction quality by \\(32.2\\%\\), proving the effectiveness of our proposed data for MVPS reconstructions. See supplementary materials for comparison between pretrained TransMVSNet [15] and TransMVSNet-RT trained on our synthetic dataset." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.886, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Light Augmented Feature Maps (LAFM). LAFM play" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "12532" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.093, + 0.09, + 0.457, + 0.136 + ], + "angle": 0, + "content": "
# of lightings141020304096
3 viewpoints1.2370.8830.8550.8630.8650.8710.892
5 viewpoints1.2440.8560.8230.8310.8400.8470.878
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.145, + 0.47, + 0.175 + ], + "angle": 0, + "content": "Table 5. Averaged Chamfer-L1 distance (mm) of DiLiGenT-MV. The network is trained with 3 views and 3 lightings per view." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.199, + 0.469, + 0.289 + ], + "angle": 0, + "content": "two key roles in our approach: (i) they aggregate features from images captured with multiple lighting conditions but the same viewpoints, and (ii) they are trained with surface normal loss which helps to preserve high-frequency details in the features. The predicted surface normals are used to further refine the reconstructed mesh." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.29, + 0.469, + 0.487 + ], + "angle": 0, + "content": "For understanding the impact of (i), we train our proposed MVPSNet with just a single lighting image per view instead of 3 lightings. Thus LAFM are only aggregated across 1 image per view. In Table 4 we observe that using a single lighting per view ('Ours (train 1 light/view)') produces worse results (1.09 vs 0.82) than using 3 lightings per view ('Ours (train 3 light/view)'). However, even using a single lighting per view produces better performance than CasMVSNet-RT (1.09 vs 1.24), which is also trained on single lighting per view. This shows that LAFM are effective in both extracting accurate information from just a single image and aggregating shading information across multiple images with varying illumination." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.487, + 0.47, + 0.609 + ], + "angle": 0, + "content": "For understanding the impact of (ii), we train our proposed MVPSNet without any surface normal loss, 'Ours (w/o normal loss). We observe 'Ours (w/o normal loss)' is quantitatively comparable to 'Ours (w/normal loss)', 0.79 vs 0.82 in L1 chamfer distance and 0.985 vs 0.985 in F-score. However, in Fig. 3 we observe that the meshes produced by 'Ours (w/o normal loss)' are significantly noisier as shown with red arrows." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.618, + 0.47, + 0.65 + ], + "angle": 0, + "content": "4.4. Effects on different numbers of viewpoints and lighting conditions" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.656, + 0.47, + 0.807 + ], + "angle": 0, + "content": "We also test the effects of the number of viewpoints and the number of lighting conditions used at inference time. The results of different combinations are shown in Table 5. We target at using sparse views to estimate depth maps, so we only test on 3 and 5 views. The results prove that although trained on 3 views, our model is able to utilize the extra information provided more views. For lighting conditions, the result gets better initially as images under more lighting conditions are provided, but then it gets slightly worse after around 10 lighting conditions." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.817, + 0.342, + 0.835 + ], + "angle": 0, + "content": "4.5. Result on real-world captures" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.47, + 0.903 + ], + "angle": 0, + "content": "We include the result on real-world captures using a simple at-home setup, which requires no special equipment. As shown in Fig 4, a user captures MVPS imagery by attaching a flashlight with a string to the tripod to move lights in" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.122 + ], + "angle": 0, + "content": "a circle around the camera. In our example, images from 5 viewpoints with 3 lighting conditions per view are captured." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.124, + 0.894, + 0.231 + ], + "angle": 0, + "content": "We automatically calibrate camera and lighting conditions using COLMAP [49, 50] and SDPSNet [8] separately. The room isn't strictly dark and contains some ambient lighting. We generate the foreground mask with an off-the-shelf segmentation algorithm. The result shows that our method produces good reconstruction and improves over CasMVSNet [20] in both details and global shapes." + }, + { + "type": "image", + "bbox": [ + 0.53, + 0.246, + 0.718, + 0.422 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.72, + 0.246, + 0.865, + 0.422 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.424, + 0.866, + 0.438 + ], + "angle": 0, + "content": "Figure 4. Results of uncalibrated in-the-wild MVPS captures." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.474, + 0.62, + 0.49 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.501, + 0.892, + 0.651 + ], + "angle": 0, + "content": "In this work, we propose a fast and generalizable approach for MVPS. We introduce Light Aggregated Feature Maps that leverage shading cues from images with the same view under multiple lighting conditions to produce richer features in textureless regions. Being trained with normal estimation, LAFM also enable higher quality reconstruction than traditional MVS methods with only little compromise to speed. When trained on the synthetic sMVPS dataset we propose, our method produces results comparable to SOTA method that is about 400x slower at inference time." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.671, + 0.597, + 0.687 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.508, + 0.697, + 0.892, + 0.753 + ], + "angle": 0, + "content": "[1] Henrik Aanæs, Rasmus Ramsbøl Jensen, George Vogiatzis, Engin Tola, and Anders Bjorholm Dahl. Large-scale data for multiple-view stereopsis. International Journal of Computer Vision, 120:153-168, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.756, + 0.894, + 0.811 + ], + "angle": 0, + "content": "[2] K. S. Arun, T. S. Huang, and S. D. Blostein. Least-squares fitting of two 3-d point sets. IEEE Transactions on Pattern Analysis and Machine Intelligence, PAMI-9(5):698-700, 1987." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.814, + 0.892, + 0.856 + ], + "angle": 0, + "content": "[3] Meghna Asthana, William AP Smith, and Patrik Huber. Neural apparent brdf fields for multiview photometric stereo. arXiv preprint arXiv:2207.06793, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.859, + 0.895, + 0.902 + ], + "angle": 0, + "content": "[4] Paul J Besl and Neil D McKay. Method for registration of 3-d shapes. In Sensor fusion IV: control paradigms and data structures, volume 1611, pages 586-606. Spie, 1992." + }, + { + "type": "list", + "bbox": [ + 0.508, + 0.697, + 0.895, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "12533" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.092, + 0.468, + 0.134 + ], + "angle": 0, + "content": "[5] Michael Bleyer, Christoph Rhemann, and Carsten Rother. Patchmatch stereo-stereo matching with slanted support windows. In *Bmvc*, volume 11, pages 1-11, 2011." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.136, + 0.468, + 0.19 + ], + "angle": 0, + "content": "[6] Mark Boss, Varun Jampani, Kihwan Kim, Hendrik P.A. Lensch, and Jan Kautz. Two-shot spatially-varying brdf and shape estimation. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.192, + 0.468, + 0.248 + ], + "angle": 0, + "content": "[7] Chenjie Cao, Xinlin Ren, and Yanwei Fu. Mvsformer: Learning robust image representations via transformers and temperature-based depth for multi-view stereo. arXiv preprint arXiv:2208.02541, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.25, + 0.468, + 0.317 + ], + "angle": 0, + "content": "[8] Guanying Chen, Kai Han, Boxin Shi, Yasuyuki Matsushita, and Kwan-Yee K Wong. Self-calibrating deep photometric stereo networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 8739-8747, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.32, + 0.468, + 0.375 + ], + "angle": 0, + "content": "[9] Guanying Chen, Kai Han, Boxin Shi, Yasuyuki Matsushita, and Kwan-Yee Kenneth Wong. Deep photometric stereo for non-lambertian surfaces. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.377, + 0.468, + 0.432 + ], + "angle": 0, + "content": "[10] Guanying Chen, Kai Han, and Kwan-Yee K Wong. Ps-fcn: A flexible learning framework for photometric stereo. In Proceedings of the European Conference on Computer Vision (ECCV), pages 3-18, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.434, + 0.468, + 0.489 + ], + "angle": 0, + "content": "[11] Guanying Chen, Michael Waechter, Boxin Shi, Kwan-Yee K Wong, and Yasuyuki Matsushita. What is learned in deep uncalibrated photometric stereo? In European Conference on Computer Vision, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.491, + 0.468, + 0.532 + ], + "angle": 0, + "content": "[12] Yang Chen and Gérard Medioni. Object modelling by registration of multiple range images. Image and vision computing, 10(3):145-155, 1992." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.534, + 0.468, + 0.589 + ], + "angle": 0, + "content": "[13] Robert T Collins. A space-sweep approach to true multi-image matching. In Proceedings CVPR IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 358-363. IEEE, 1996." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.591, + 0.468, + 0.672 + ], + "angle": 0, + "content": "[14] Yikang Ding, Wentao Yuan, Qingtian Zhu, Haotian Zhang, Xiangyue Liu, Yuanjiang Wang, and Xiao Liu. Transmvsnet: Global context-aware multi-view stereo network with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8585-8594, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.675, + 0.468, + 0.757 + ], + "angle": 0, + "content": "[15] Yikang Ding, Wentao Yuan, Qingtian Zhu, Haotian Zhang, Xiangyue Liu, Yuanjiang Wang, and Xiao Liu. Transmvsnet: Global context-aware multi-view stereo network with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8585-8594, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.759, + 0.468, + 0.815 + ], + "angle": 0, + "content": "[16] Yasutaka Furukawa, Brian Curless, Steven M Seitz, and Richard Szeliski. Towards internet-scale multi-view stereo. In 2010 IEEE computer society conference on computer vision and pattern recognition, pages 1434-1441. IEEE, 2010." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.817, + 0.468, + 0.857 + ], + "angle": 0, + "content": "[17] Yasutaka Furukawa and Jean Ponce. Accurate, dense, and robust multiview stereopsis. IEEE transactions on pattern analysis and machine intelligence, 32(8):1362-1376, 2009." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.859, + 0.468, + 0.9 + ], + "angle": 0, + "content": "[18] Khang Truong Giang, Soohwan Song, and Sungho Jo. Curvature-guided dynamic scale networks for multi-view stereo. arXiv preprint arXiv:2112.05999, 2021." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.468, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.148 + ], + "angle": 0, + "content": "[19] Michael Goesele, Noah Snavely, Brian Curless, Hugues Hoppe, and Steven M Seitz. Multi-view stereo for community photo collections. In 2007 IEEE 11th International Conference on Computer Vision, pages 1-8. IEEE, 2007." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.151, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[20] Xiaodong Gu, Zhiwen Fan, Siyu Zhu, Zuozhuo Dai, Feitong Tan, and Ping Tan. Cascade cost volume for high-resolution multi-view stereo and stereo matching. 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.193, + 0.892, + 0.261 + ], + "angle": 0, + "content": "[21] Xiaodong Gu, Zhiwen Fan, Siyu Zhu, Zuozhuo Dai, Feitong Tan, and Ping Tan. Cascade cost volume for high-resolution multi-view stereo and stereo matching. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2495-2504, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.264, + 0.892, + 0.304 + ], + "angle": 0, + "content": "[22] Carlos Hernandez, George Vogiatzis, and Roberto Cipolla. Multiview photometric stereo. IEEE Transactions on Pattern Analysis and Machine Intelligence, 30(3):548-554, 2008." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.307, + 0.892, + 0.374 + ], + "angle": 0, + "content": "[23] Po-Han Huang, Kevin Matzen, Johannes Kopf, Narendra Ahuja, and Jia-Bin Huang. Deepmvs: Learning multi-view stereopsis. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 2821-2830, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.377, + 0.892, + 0.418 + ], + "angle": 0, + "content": "[24] Satoshi Ikehata. Ps-transformer: Learning sparse photometric stereo network using self-attention mechanism. arXiv preprint arXiv:2211.11386, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.421, + 0.892, + 0.475 + ], + "angle": 0, + "content": "[25] Mengqi Ji, Juergen Gall, Haitian Zheng, Yebin Liu, and Lu Fang. Surfacenet: An end-to-end 3d neural network for multiview stereopsis. In Proceedings of the IEEE International Conference on Computer Vision, pages 2307-2315, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.477, + 0.892, + 0.545 + ], + "angle": 0, + "content": "[26] Sing Bing Kang, Richard Szeliski, and Jinxiang Chai. Handling occlusions in dense multi-view stereo. In Proceedings of the 2001 IEEE Computer Society Conference on Computer Vision and Pattern Recognition. CVPR 2001, volume 1, pages I-I. IEEE, 2001." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.548, + 0.892, + 0.616 + ], + "angle": 0, + "content": "[27] Berk Kaya, Suryansh Kumar, Carlos Oliveira, Vittorio Ferrari, and Luc Van Gool. Uncertainty-aware deep multi-view photometric stereo. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12601-12611, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.619, + 0.892, + 0.673 + ], + "angle": 0, + "content": "[28] Berk Kaya, Suryansh Kumar, Carlos Oliveira, Vittorio Ferrari, and Luc Van Gool. Multi-view photometric stereo revisited. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 3126-3135, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.676, + 0.892, + 0.743 + ], + "angle": 0, + "content": "[29] Berk Kaya, Suryansh Kumar, Francesco Sarno, Vittorio Ferrari, and Luc Van Gool. Neural radiance fields approach to deep multi-view photometric stereo. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1965-1977, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.746, + 0.892, + 0.801 + ], + "angle": 0, + "content": "[30] Michael Kazhdan, Matthew Bolitho, and Hugues Hoppe. Poisson surface reconstruction. In Proceedings of the fourth Eurographics symposium on Geometry processing, volume 7, page 0, 2006." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.803, + 0.892, + 0.843 + ], + "angle": 0, + "content": "[31] Michael Kazhdan and Hugues Hoppe. Screened poisson surface reconstruction. ACM Transactions on Graphics (ToG), 32(3):1-13, 2013." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.846, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[32] Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: Benchmarking large-scale scene reconstruction. ACM Transactions on Graphics (ToG), 36(4):1-13, 2017." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "12534" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.12 + ], + "angle": 0, + "content": "[33] Christoph Lassner and Michael Zollhöfer. Pulsar: Efficient sphere-based neural rendering. arXiv:2004.07484, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.469, + 0.191 + ], + "angle": 0, + "content": "[34] Min Li, Zhenglong Zhou, Zhe Wu, Boxin Shi, Changyu Diao, and Ping Tan. Multi-view photometric stereo: A robust solution and benchmark dataset for spatially varying isotropic materials. IEEE Transactions on Image Processing, 29:4159-4173, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.192, + 0.469, + 0.261 + ], + "angle": 0, + "content": "[35] Zhengqin Li, Zexiang Xu, Ravi Ramamoorthi, Kalyan Sunkavalli, and Manmohan Chandraker. Learning to reconstruct shape and spatially-varying reflectance from a single image. In SIGGRAPH Asia 2018 Technical Papers, page 269. ACM, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.263, + 0.469, + 0.319 + ], + "angle": 0, + "content": "[36] Daniel Lichy, Soumyadip Sengupta, and David W Jacobs. Fast light-weight near-field photometric stereo. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12612-12621, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.321, + 0.469, + 0.388 + ], + "angle": 0, + "content": "[37] Daniel Lichy, Soumyadip Sengupta, and David W. Jacobs. Fast light-weight near-field photometric stereo. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 12612-12621, June 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.391, + 0.469, + 0.446 + ], + "angle": 0, + "content": "[38] Daniel Lichy, Jiaye Wu, Soumyadip Sengupta, and David W. Jacobs. Shape and material capture at home. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 6123-6133, June 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.448, + 0.469, + 0.503 + ], + "angle": 0, + "content": "[39] Daniel Lichy, Jiaye Wu, Soumyadip Sengupta, and David W Jacobs. Shape and material capture at home. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6123-6133, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.505, + 0.469, + 0.546 + ], + "angle": 0, + "content": "[40] William E Lorensen and Harvey E Cline. Marching cubes: A high resolution 3d surface construction algorithm. ACM siggraph computer graphics, 21(4):163-169, 1987." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.548, + 0.469, + 0.616 + ], + "angle": 0, + "content": "[41] Keyang Luo, Tao Guan, Lili Ju, Haipeng Huang, and Yawei Luo. P-mvsnet: Learning patch-wise matching confidence aggregation for multi-view stereo. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10452-10461, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.619, + 0.469, + 0.687 + ], + "angle": 0, + "content": "[42] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3d reconstruction in function space. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 4460-4470, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.689, + 0.469, + 0.744 + ], + "angle": 0, + "content": "[43] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.746, + 0.469, + 0.8 + ], + "angle": 0, + "content": "[44] Diego Nehab, Szymon Rusinkiewicz, James Davis, and Ravi Ramamoorthi. Efficiently combining positions and normals for precise 3d geometry. ACM transactions on graphics (TOG), 24(3):536-543, 2005." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.803, + 0.469, + 0.871 + ], + "angle": 0, + "content": "[45] Michael Oechsle, Songyou Peng, and Andreas Geiger. Unisurf: Unifying neural implicit surfaces and radiance fields for multi-view reconstruction. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 5589-5599, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[46] Jaesik Park, Sudipta N Sinha, Yasuyuki Matsushita, Yu-Wing Tai, and In So Kweon. Multiview photometric stereo" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.133 + ], + "angle": 0, + "content": "using planar mesh parameterization. In Proceedings of the IEEE International Conference on Computer Vision, pages 1161-1168, 2013." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.135, + 0.892, + 0.203 + ], + "angle": 0, + "content": "[47] Jaesik Park, Sudipta N Sinha, Yasuyuki Matsushita, Yu-Wing Tai, and In So Kweon. Robust multiview photometric stereo using planar mesh parameterization. IEEE transactions on pattern analysis and machine intelligence, 39(8):1591-1604, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.205, + 0.892, + 0.259 + ], + "angle": 0, + "content": "[48] Nikhila Ravi, Jeremy Reizenstein, David Novotny, Taylor Gordon, Wan-Yen Lo, Justin Johnson, and Georgia Gkioxari. Accelerating 3d deep learning with pytorch3d. arXiv:2007.08501, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.261, + 0.892, + 0.314 + ], + "angle": 0, + "content": "[49] Johannes L Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4104-4113, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.316, + 0.892, + 0.399 + ], + "angle": 0, + "content": "[50] Johannes L Schonberger, Enliang Zheng, Jan-Michael Frahm, and Marc Pollefeys. Pixelwise view selection for unstructured multi-view stereo. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part III 14, pages 501-518. Springer, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.4, + 0.892, + 0.468 + ], + "angle": 0, + "content": "[51] Soumyadip Sengupta, Angjoo Kanazawa, Carlos D Castillo, and David W Jacobs. Sfsnet: Learning shape, reflectance and illuminance of facesin the wild'. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 6296-6305, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.47, + 0.892, + 0.537 + ], + "angle": 0, + "content": "[52] Boxin Shi, Zhe Wu Mo, Dinglong Duan, Sai-Kit Yeung, and Ping Tan. A benchmark dataset and evaluation for non-lambertian and uncalibrated photometric stereo. IEEE Trans. on Pattern Analysis and Machine Intelligence (TPAMI), 41(2):271-284, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.539, + 0.892, + 0.621 + ], + "angle": 0, + "content": "[53] Pratul P Srinivasan, Boyang Deng, Xiuming Zhang, Matthew Tancik, Ben Mildenhall, and Jonathan T Barron. Nerv: Neural reflectance and visibility fields for relighting and view synthesis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7495-7504, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.623, + 0.892, + 0.691 + ], + "angle": 0, + "content": "[54] Christoph Strecha, Rik Fransens, and Luc Van Gool. Wide-baseline stereo from multiple views: a probabilistic account. In Proceedings of the 2004 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 2004. CVPR 2004., volume 1, pages I-I. IEEE, 2004." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.692, + 0.892, + 0.761 + ], + "angle": 0, + "content": "[55] Christoph Strecha, Rik Fransens, and Luc Van Gool. Combined depth and outlier estimation in multi-view stereo. In 2006 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'06), volume 2, pages 2394-2401. IEEE, 2006." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.762, + 0.892, + 0.802 + ], + "angle": 0, + "content": "[56] Jiaming Sun, Yiming Xie, Linghao Chen, Xiaowei Zhou, and Hujun Bao. NeuralRecon: Real-time coherent 3D reconstruction from monocular video. CVPR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.804, + 0.892, + 0.858 + ], + "angle": 0, + "content": "[57] Olivia Wiles and Andrew Zisserman. Silnet: Single- and multi-view reconstruction by learning from silhouettes. In British Machine Vision Conference 2017, BMVC 2017, London, UK, September 4-7, 2017. BMVA Press, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.86, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[58] Robert J Woodham. Photometric method for determining surface orientation from multiple images. Optical engineering, 19(1):139-144, 1980." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.957 + ], + "angle": 0, + "content": "12535" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[59] Qingshan Xu and Wenbing Tao. Learning inverse depth regression for multi-view stereo with correlation cost volume. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 12508-12515, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.149, + 0.468, + 0.204 + ], + "angle": 0, + "content": "[60] Zexiang Xu, Kalyan Sunkavalli, Sunil Hadap, and Ravi Ramamoorthi. Deep image-based relighting from optimal sparse samples. ACM Transactions on Graphics (TOG), 37(4):126, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.207, + 0.468, + 0.26 + ], + "angle": 0, + "content": "[61] Wenqi Yang, Guanying Chen, Chaofeng Chen, Zhenfang Chen, and Kwan-Yee K Wong. Ps-nerf: Neural inverse rendering for multi-view photometric stereo. arXiv preprint arXiv:2207.11406, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.263, + 0.468, + 0.318 + ], + "angle": 0, + "content": "[62] Yao Yao, Zixin Luo, Shiwei Li, Tian Fang, and Long Quan. Mvsnet: Depth inference for unstructured multi-view stereo. In Proceedings of the European conference on computer vision (ECCV), pages 767-783, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.32, + 0.468, + 0.374 + ], + "angle": 0, + "content": "[63] Yao Yao, Zixin Luo, Shiwei Li, Tianwei Shen, Tian Fang, and Long Quan. Recurrent mvvsnet for high-resolution multiview stereo depth inference. Computer Vision and Pattern Recognition (CVPR), 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.376, + 0.468, + 0.444 + ], + "angle": 0, + "content": "[64] Lior Yariv, Yoni Kasten, Dror Moran, Meirav Galun, Matan Atzmon, Basri Ronen, and Yaron Lipman. Multiview neural surface reconstruction by disentangling geometry and appearance. Advances in Neural Information Processing Systems, 33:2492-2502, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.446, + 0.468, + 0.515 + ], + "angle": 0, + "content": "[65] Kai Zhang, Fujun Luan, Qianqian Wang, Kavita Bala, and Noah Snavely. Physg: Inverse rendering with spherical gaussians for physics-based material editing and relighting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5453-5462, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.517, + 0.468, + 0.585 + ], + "angle": 0, + "content": "[66] Xiuming Zhang, Pratul P Srinivasan, Boyang Deng, Paul Debevec, William T Freeman, and Jonathan T Barron. Nerfactor: Neural factorization of shape and reflectance under an unknown illumination. ACM Transactions on Graphics (TOG), 40(6):1-18, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.587, + 0.468, + 0.628 + ], + "angle": 0, + "content": "[67] Zhengyou Zhang. Iterative point matching for registration of free-form curves and surfaces. International journal of computer vision, 13(2):119-152, 1994." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.63, + 0.468, + 0.685 + ], + "angle": 0, + "content": "[68] Zhenglong Zhou, Zhe Wu, and Ping Tan. Multi-view photometric stereo with spatially varying isotropic materials. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1482-1489, 2013." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.685 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.957 + ], + "angle": 0, + "content": "12536" + } + ] +] \ No newline at end of file diff --git a/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/0b36b82c-cf6a-406b-8b06-65bc02693944_origin.pdf b/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/0b36b82c-cf6a-406b-8b06-65bc02693944_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..d098cfdf7fa818856479607f074e193e7a2cb980 --- /dev/null +++ b/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/0b36b82c-cf6a-406b-8b06-65bc02693944_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:032117bd61acc8052a9bfedb7fa8312c8e035daa2a1a13374b8dca6b2d7f6961 +size 5540915 diff --git a/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/full.md b/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/full.md new file mode 100644 index 0000000000000000000000000000000000000000..5f9e79e31a64b109918d094512008dbe043a32b7 --- /dev/null +++ b/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/full.md @@ -0,0 +1,354 @@ +# MVPSNet: Fast Generalizable Multi-view Photometric Stereo + +Dongxu Zhao $^{1}$ Daniel Lichy $^{2}$ Pierre-Nicolas Perrin $^{1}$ Jan-Michael Frahm $^{1}$ Soumyadip Sengupta $^{1}$ + +1University of North Carolina at Chapel Hill 2University of Maryland, College Park + +{dongxuzl, pnperrin, jmf, ronisen}@cs.unc.edu dlichy@umd.edu + +# Abstract + +We propose a fast and generalizable solution to Multiview Photometric Stereo (MVPS), called MVPSNet. The key to our approach is a feature extraction network that effectively combines images from the same view captured under multiple lighting conditions to extract geometric features from shading cues for stereo matching. We demonstrate these features, termed 'Light Aggregated Feature Maps' (LAFM), are effective for feature matching even in textureless regions, where traditional multi-view stereo methods often fail. Our method produces similar reconstruction results to PS-NeRF, a state-of-the-art MVPS method that optimizes a neural network per-scene, while being $411 \times$ faster (105 seconds vs. 12 hours) in inference. Additionally, we introduce a new synthetic dataset for MVPS, sMVPS, which is shown to be effective for training a generalizable MVPS method. + +# 1. Introduction + +3D reconstruction of an object can be achieved either through camera viewpoint variations, Multi-view Stereo (MVS), or by lighting direction variations, Photometric Stereo (PS). Both MVS and PS have relative strengths and weaknesses. While MVS succeeds in obtaining accurate global shapes, it suffers in textureless regions due to poor feature matching, often resulting in reconstructions that lack local details. On the other hand, PS produces accurate local details, even in textureless regions, by using shading information but fails to reconstruct accurate global shapes. In this paper, we focus on the problem of Multi-view Photometric Stereo (MVPS) where both camera viewpoint and lighting direction variations are used to accurately reconstruct global and local details of a 3D shape, even in textureless regions. + +3D reconstruction techniques that produce high-quality results using only viewpoint variations (MVS) rely on test-time optimization, often by training neural networks per + +scene [53, 64, 66]. These methods are computationally inefficient, typically taking hours of computing time on a high-end GPU for each object. Existing MVs methods [20, 56, 62] that focus on computational efficiency employ feed-forward neural networks that are efficient but fail to produce high-quality details, especially in textureless regions. Existing MVPS approaches can produce high-quality reconstructions but require computationally inefficient per-scene training or optimization [27, 28, 29, 61]. Sometimes additional manual efforts and carefully crafted refinement steps are also needed [34, 47]. In contrast, we propose an efficient feed-forward neural architecture, MVPSNet, that can generalize to unseen objects and achieve similar reconstruction quality to that of per-scene optimization techniques while being computationally efficient during inference. + +We design MVPSNet by taking inspiration from various deep MVS architectures [7, 14, 18, 20, 62] that are generalizable, computationally efficient, and can operate on high-resolution images. However, these approaches often fail in textureless regions, and their reconstructed meshes often lack details. We choose the CasMVsNet [20] architecture as our feature matching module, which has been repeatedly used by various MVS pipelines [7, 14, 18] for its simplicity and efficiency, and augment it to effectively incorporate lighting variation cues for better prediction of 3D shapes. In this way, we propose a feed-forward generalizable approach to Multi-view Photometric Stereo. + +We introduce a multi-scale feature representation, called Light Aggregated Feature Maps (LAFM), whose role is to extract detailed geometric features from images by utilizing lighting variations. For brevity, we define Multi-light Images as a collection of images taken from the same viewpoint under different directional lighting conditions. Our intuition is that LAFM can efficiently aggregate shading patterns from multi-light images, by creating an 'artificial shading texture' in the textureless region. Multi-scale LAFM will then be used to construct a sequence of cost volumes to match features across sparse views in order to + +predict a depth map for a reference view. We also predict surface normals from LAFM for each viewpoint, enabling LAFM to capture features related to high-frequency local details. The predicted surface normal can be used in addition to the depth maps to produce a more detailed mesh than using the depth maps alone. + +To train the proposed MVPSNet architecture, we introduce a new synthetic MVPS dataset, sMVPS dataset. It consists of shapes from sculpture dataset [57] and random compositions of primitive shapes generated by [60]. We render these shapes with spatially varying Cook-Torrance BRDF under different camera viewpoints and lighting directions. We train MVPSNet on these rendered images with ground-truth supervision over predicted depth and surface normal maps. The trained model generalizes to real-world test scenes from DiLiGenT-MV [34] dataset. We show that simply re-training CasMVsNet on our dataset improves reconstruction quality over the pre-trained model on DiLiGenT-MV by $32\%$ , proving the effectiveness of our synthetic MVPS dataset for generalization. + +We evaluate our approach on the only publicly available MVPS benchmark, the DiLiGenT-MV [34] dataset. Compared to the state-of-the-art MVPS technique, PS-NeRF [61], which optimizes a neural network per-scene, our proposed MVPSNet is $\sim 411\times$ faster (105 seconds vs 12 hours) while producing similar reconstruction quality (L1 Chamfer distance of 0.82 vs 0.81, F-score on L2 distance of 0.985 vs 0.983). We further show that adding LAFM significantly improves reconstruction quality over CasMVSNet by $34\%$ in L1 Chamfer distance. We also observe that refining the reconstructed mesh derived from depth maps with predicted surface normals from LAFM improves reconstruction quality as shown in Fig 3. + +In summary, the key contributions of this paper include: - Light Aggregated Feature Maps (LAFM) that can efficiently utilize multi-light images to extract detailed geometric features, especially in textureless regions. The surface normal predicted from LAFM also improves mesh reconstruction quality. - A synthetic MVPS dataset for training generalizable MVPS methods, which also improves Cas-MVSNet by $32\%$ . - A fast and generalizable Multi-view Photometric Stereo pipeline that is $411\times$ faster while producing similar reconstruction accuracy compared to state-of-the-art per-scene optimization approach [61]. + +# 2. Related work + +Multi-view Stereo (MVS). MVS is a 3D reconstruction technique that utilizes multiple images captured from different viewpoints. While various techniques for MVS have been proposed, one commonly used approach that is relevant to our work involves constructing cost volumes similar to Plane Sweeping Algorithm [13] and then predicting per-view depth maps [21, 25, 41, 59, 62, 63] or disparity + +
MethodGeneralizableMesh Reconstruction
PJ16 [47]XBase mesh+displacement map
LZ20 [34]X3D points+PSR [30]+Optimization [44]
BKW22 [29]XMLP+Marching Cube [40]
BKC22 [27]XMLP+Marching Cube [40]
PS-NeRF [61]XMLP+MISE [42]
BKW23 [28]XMLP+Marching Cube [40]
Ours✓3D Points+Screened Poisson [31]
+ +Table 1. Comparison of our method with prior MVPS methods. + +maps [23]. To create a cost volume, features are matched across neighboring viewpoints, and the quality of the features plays a critical role in the final reconstruction quality. Traditional methods [5, 16, 17, 19, 26, 50, 54, 55] use human-defined or hand-crafted image processing operators to extract feature maps. With recent advances in deep learning, features learned from deep neural networks have been proven to be effective. + +The most relevant previous works are MVSNet [62] and its variations. MVSNet [62] uses homography to warp feature maps and a 3D CNN to regularize cost volumes. CasMVSNet [21] outperforms MVSNet in terms of accuracy and efficiency by building the 3D cost volume in a cascaded manner. TransMVSNet [15] builds upon CasMVSNet and adopts a transformer to consider intra-image and inter-image feature interactions, which further improves the results of CasMVSNet. + +Photometric Stereo (PS). PS (introduced in [58]) uses lighting variation to reconstruct 3D shapes from a single viewpoint (see [52] for surveys). Calibrated PS approaches, like Chen et al. [10], train a neural network to predict surface normals using data with known lightings. Uncalibrated PS approaches [8, 9, 11] first predict the lighting parameters before solving for surface normals. While most PS works use a large number of images for inference, some use fewer [24, 38], or even one image [6, 35, 36, 51] (often called Shape from Shading). PS approaches are mostly based on feed-forward networks that generalize and can produce near real-time inference with low computational cost [37]. + +Multi-view Photometric Stereo (MVPS). MVPS was initially proposed in [22] by combining PS with object silhouettes to reconstruct textureless shiny objects with fine details. However, this method only works well for specific parametric BRDF models [27]. Later, Li et al. [34, 68] propose to get iso-depth contours from PS images and sparse 3D points using structure-from-motion, which are propagated to recover a complete 3D shape. Park et al. [46, 47] use a planar mesh parameterization technique to parameterize a coarse mesh from MVS and take advantage of this 2D parameter domain to perform MVPS. Some of these traditional MVPS methods achieve high-quality results, but they require an initial 3D reconstruction and their performance is sensitive to it. Besides, they consist of multiple steps, so careful execution or expert interventions are often needed to + +![](images/6911031e21945bca173a6154e01d13dc53a995dc430952499b2012169efb6715.jpg) +Figure 1. Overview of our network architecture. (a) Light Informed Feature Extractor (LIFE) produces a multi-scale feature representation; (b) Light Aggregated Feature Maps (LAFM) Extractor aggregates these features across images of varying lighting conditions but same view; and (c) LAFM is used to create cost volumes and predict depth maps, similar to CasMVSNet [21], in addition to normal map. + +![](images/d95403bcd3b4219a6a8dce8c49c8505fe7927ee77ed320b502b3d0a23426d26d.jpg) + +![](images/49d73e923de6170f4d63a0b10ec766f3f63222806a5910c6638ebbc67d16d910.jpg) + +get good results [34, 47]. In contrast, our proposed method trains a neural network end-to-end and the inference only requires one feed-forward pass of the trained network. + +Recently, inspired by NeRF [43], various algorithms have been proposed that optimize a neural network perscene for MVPS. Kaya et al. [29] train a deep PS network first and condition the color rendering in NeRF [43] on normals predicted from PS. The reconstructed mesh, however, exhibits multiple artifacts. The authors in [27] propose to train a deep PS network and a deep MVS network extended with uncertainty estimation separately, and use these to fit the SDF represented by an MLP. To further enable reconstruction on anisotropic and glossy objects, Kaya et al. [28] add a neural volume rendering module to the SDF MLP in [27] to better fuse PS and MVS measurements. PS-NeRF [61] solves the task of jointly estimating the geometry, materials and lights. It first regularizes the gradient of a UNISURF [45] with estimated normals from PS, and then uses separate MLPs to explicitly model surface normal, BRDF, lights, and visibility which are optimized based on a shadow-aware differentiable rendering layer. Recent works have also used physically based differentiable rendering either inside a NeRF framework [3] or separately for optimization [65]. While per-scene optimization methods often generate precise reconstruction results, they have to optimize an individual model for each object separately, which is computationally inefficient. Thus, we propose a solution to Multi-view Photometric Stereo training on a new synthetic MVPS dataset, which is generalizable and can achieve similar results as SOTA per-scene optimization methods. + +# 3. Our approach + +# 3.1. Problem setup + +We focus on the problem of calibrated multi-view photometric stereo, i.e. the locations of the light sources and the cameras are known a priori (calibrated prior to capture). The input data consists of a set of multi-light images of an object captured from multiple views. + +Concretely, for the $i$ -th view we have $M_{i}$ images with varying lighting directions $l_{ij}$ , denoted as $I_{ij}$ . We refer to the collection $\{I_{i1}, \dots, I_{iM_i}\}$ as the multi-light images for the $i$ -th view. For each view, we are given camera intrinsic matrix $K_{i}$ and camera extrinsic parameters in the form of a rotation matrix, $R_{i}$ , and a translation vector, $t_i$ . Similar to virtually all MVS methods, we assume that we are provided with the depth range for each view. + +# 3.2. Motivation + +Our approach follows a long line of work in Multi-view Stereo which uses Plane Sweep to construct a cost volume and predicts a depth map aligned with a reference image. Recent advances in Plane Sweep Stereo using deep neural networks, especially CasMVSNet [21], have proven to be generalizable across scenes and can predict high-resolution reconstruction in a matter of seconds. In contrast to previous Multi-view Photometric Stereo approaches, which optimize a neural network per scene, our goal is to produce a generalizable solution. Thus we aim to build upon the Plane Sweep stereo architecture proposed in CasMVSNet [21]. + +CasMVSNet learns a deep image feature encoder for extracting representative features that can aid in feature matching across multiple views and create better cost vol + +umes. However, these features are often ambiguous for non-textured regions and fail to preserve the geometric details. We believe incorporating lighting variations along with viewpoint variations can lead to better features, which in turn will produce better cost volumes and depth maps. + +To this end, we introduce 'Light Aggregated Feature Maps' (LAFM), whose goal is to extract detailed geometric features, even for textureless regions, by jointly learning to aggregate feature maps over all images captured from a single viewpoint and multiple lighting directions. To obtain effective features that capture geometric details we use LAFM to regress surface normals. We show that LAFM provide superior information for stereo-matching than single-lighting feature maps (as used in CasMVSNet) and thus provide a better reconstruction. We also show that surface normals predicted using LAFM can be used during mesh reconstruction to improve quality over depth maps alone. + +Our approach proceeds in three stages. We first extract multi-scale feature representation from each image, along with its lighting directions, using a shared neural network, 'Light Informed Feature Extractor' (LIFE). To aggregate features extracted by LIFE across all images under the same viewpoint but different lighting conditions, we use max-pooling operation. We can then create a cost volume for the reference view by matching LAFM of the reference view with all the LAFM from neighboring views. Finally, for each reference view, we predict a depth map using cost volume regularization and a surface normal map from the LAFM. We train our system in a multi-task learning framework with supervised losses over depth and normal predictions. In the following sections, we provide the details of our MVPSNet pipeline. An overview of MVPSNet architecture is illustrated in Figure 1. + +# 3.3. Light Aggregated Feature Maps (LAFM) + +We introduce Light Aggregated Feature Maps (LAFM) that provide geometrically distinct multi-scale features for cost volume creation in a Plane Sweep Stereo approach. Our key observation is that the multi-light images provide us with important information for feature matching. For textureless regions, the variation in shading (including cast and attached shadows) created by different lighting directions can be interpreted as 'artificial' textures. Thus the role of LAFM for textureless regions is to capture the variation in shading as an 'artificial' texture that can be used for feature matching across different viewpoints. We also use LAFM to predict surface normal maps, enabling it to capture geometric details required for producing high-quality normal maps. Hence LAFM can capture better features for textureless regions and for reconstructing details, which were absent in the usual deep image features used in deep multi-view stereo algorithms. + +We first define a multi-scale feature extractor, Light In + +formed Feature Extractor (LIFE), that takes an image $I_{ij}$ associated with its lighting direction $l_{ij}$ as input and produces feature maps at three different scales $F_{ij}^{1}, F_{ij}^{2}, F_{ij}^{3}$ at resolutions $1/4, 1/2, 1$ of the input resolution, and another feature map $NF_{ij}$ that will be used for normal prediction. The network architecture of LIFE is shown in Fig. 1(a) and will be discussed in details in the supplementary material. + +$$ +N F _ {i j}, F _ {i j} ^ {1}, F _ {i j} ^ {2}, F _ {i j} ^ {3} = L I F E \left(I _ {i j}, l _ {i j}; \theta\right) \tag {1} +$$ + +Note $l_{ij}$ is of the same resolution as $I_{ij}$ by simply repeating the same 3-dimensional lighting vector at each pixel. + +Then we extract these multi-scale features for every image captured under the same viewpoint and different lighting conditions, $\{I_{i1},\dots,I_{iM_i}\}$ , using the same shared encoder LIFE. Let the feature maps obtained from these images be denoted as: $\{NF_{ij},F_{ij}^{1},F_{ij}^{2},F_{ij}^{3}\}$ , $j = 1,\dots,M_i$ . We create 'Light Aggregated Feature Maps' (LAFM) from these multi-scale feature representations by performing a max-pooling operation for each scale. Pooling operations can handle various numbers of input feature maps and are order-agnostic. Moreover, max-pooling helps save the most prominent feature across all views and ignores non-activated features, which automatically handles shadows casted by directional lights [10]. + +$$ +F _ {i} ^ {s} = \max _ {j} F _ {i j} ^ {s}, \quad \forall s = 1, 2, 3 \tag {2} +$$ + +$$ +N F _ {i} = \max _ {j} N F _ {i j}. \tag {3} +$$ + +Thus for multi-light images we obtain LAFM as $LF_{i} = \{NF_{i},F_{i}^{1},F_{i}^{2},F_{i}^{3}\}$ + +The features at 3 scales $F_{i}^{1}, F_{i}^{2}, F_{i}^{3}$ are then used to build cost volumes using differentiable homography warping, which we will talk about in detail in Section 3.4. The normal feature $NF_{i}$ is fed into a lightweight normal regression network to predict per-view normal map, as shown in Figure 1(c). With the supervision from normal information and depth information, our LAFM benefit from the advantages of both MVS and PS which are good at global shape modeling and high-frequency component reconstruction, respectively. + +# 3.4. Cost volume and depth map prediction + +Given Light Aggregated Feature Maps (LAFM), $LF_{i}$ for each view $i$ , we aim to build a cost volume for each reference view by selecting a set of source views with sufficient overlap. We adopt the multi-scale cost volume construction proposed in CasMVSNet [21], where the plane sweep is first performed at a low resolution and then at higher resolutions. Depth estimated from the previous step is used for generating depth proposals for the next step. Multi-scale cost volume reconstruction and depth map prediction follow the following steps. + +Step 1: Depth hypothesis generation. We generate hypothesis depths for each pixel based on the lower resolution + +depth estimated at the previous resolution. We store these in $h$ , where + +$$ +h (u, v, w) = U p \left(D ^ {s - 1}\right) (u, v) + \Delta_ {s} \left(\frac {w}{N _ {s} - 1} - \frac {1}{2}\right). \tag {4} +$$ + +Here $h(u,v,w)$ is the $w$ -th depth hypothesis at pixel $(u,v)$ . $Up(D^{s - 1})$ is the depth map at the previous lower resolution upsampled to the current resolution. $\Delta_s$ is the length of the depth interval we are searching at scale $s$ . $N_{s}$ is the number of hypothesis depths at the current scale. + +Step 2: Cost volume construction. Building cost volume is a way of robustly searching for matches between a point $(u, v)$ in the reference image $I_r$ and a point on the corresponding epipolar line in the source image $I_{s_k}$ . Concretely, consider a pixel $(u, v)$ in the reference image. For every hypothesis depth $d$ , we get a corresponding point in the source image on the epipolar line for $(u, v)$ . We denote this point by $(u', v') = \mathrm{warp}_{rs_k}(u, v, d)$ where + +$$ +\left[ \begin{array}{l} u ^ {\prime} \\ v ^ {\prime} \\ 1 \end{array} \right] \sim K _ {s _ {k}} R _ {s _ {k}} ^ {T} \left[ \left(R _ {r} K _ {r} ^ {- 1} d \left[ \begin{array}{l} u \\ v \\ 1 \end{array} \right] + t _ {r}\right) - t _ {s} \right]. \tag {5} +$$ + +We then construct a per-image volume: + +$$ +F _ {i} \operatorname {v o l} _ {i} ^ {s} (u, v, w) = F _ {i} ^ {s} \left(w a r p (u, v, h (u, v, w))\right), \tag {6} +$$ + +where $i$ runs over the reference and source views i.e. $i \in \{r, s_1, \dots, s_k\}$ . These volumes are then aggregated into a single cost volume by taking their variance, which checks for the photo-consistency of the depth proposal $d$ for pixel $(u, v)$ in the reference image and the corresponding pixels in the warped sources images $s_k$ : + +$$ +\operatorname {a g g} _ {-} \operatorname {v o l} ^ {s} (u, v, w) = \operatorname {v a r} _ {i} \left(\mathrm {F} _ {-} \operatorname {v o l} (\mathrm {u}, \mathrm {v}, \mathrm {w}) _ {i} ^ {s}\right). \tag {7} +$$ + +Step 3: Cost regularization. In this step we pass the aggregated volume through a 3D convolutional network and take a softmax to convert it to a match probability, using + +$$ +\operatorname {p r o b} _ {-} \operatorname {v o l} = \operatorname {s o f t} _ {-} \max _ {w} \left(\operatorname {r e g} _ {-} \operatorname {n e t} ^ {s} \left(\operatorname {a g g} _ {-} \operatorname {v o l} ^ {s}\right)\right). \tag {8} +$$ + +Step 4: Regression. We take the expectation of the hypothesis depths over the match probability given by the probability volume to obtain the depth at the current scale, which enables sub-pixel estimation. + +$$ +D ^ {s} (u, v) = \sum_ {w} \operatorname {p r o b} _ {-} \operatorname {v o l} (u, v, w) h (u, v, w). \tag {9} +$$ + +This whole process is summarized in algorithm 1 + +# Algorithm 1 MVPSNet Algorithm + +1: $NF_{ij},F_{ij}^{1},F_{ij}^{2},F_{ij}^{3} = \mathrm{LIFE}(I_{ij},l_{ij};\theta)$ +2: $NF_{i} = \max_{j}NF_{ij};F_{i}^{s} = \max_{j}F_{ij}^{s}\quad \forall s = 1,2,3.$ +3: $N_{i} =$ normal_regression_net $(NF_{i})$ +4: $D^0 (u,v) = (\max_{-}\mathrm{depth} + \min_{-}\mathrm{depth}) / 2$ +5: for $s = 1$ to 3 do +6: $h(u,v,w) = Up(D^{s - 1})(u,v) + \Delta_s(\frac{w}{N_s - 1} -\frac{1}{2})$ +7: $\mathrm{F\_vol}_i^s (u,v,w) = F_i^s (warp(u,v,h(u,\bar{v},w)))$ +8: $\mathrm{agg\_vol}^s (u,v,w) = \mathrm{var}_i(\mathrm{F\_vol}_i^s)$ +9: prob_vol = soft_max_w(reg_net^s(agg_vol^s)) +10: $D^{s}(u,v) = \sum_{w}\mathrm{prob\_vol}(u,v,w)h(u,v,w)$ +11: end for + +![](images/7f52ef90ed05c68cde359925a5676c48272332c0e235541284eef42d5954a149.jpg) +Figure 2. Example images from proposed synthetic MVPS dataset. + +Once we have depth and surface normal for each view, our mesh reconstruction pipeline consists of three steps: depth filtering, lifting depth and normal maps to a point cloud, and reconstructing the mesh using Screened Poisson [31] (See supplementary materials for details). + +# 3.5. Synthetic MVPS dataset + +A key component of our method is that we can learn better features for stereo matching, especially in textureless regions, by learning features that incorporate multi-lighting cues. However, there is no existing MVPS dataset that is large enough for neural network training. Therefore, we generate a large-scale synthetic dataset, sMVPS, consisting of two sub-datasets, sMVPS-sculpture (800 train scenes/4 test scenes) and sMVPS-random (1000 train scenes/20 test scenes). + +sMVPS-sculpture consists of objects from the sculpture dataset [57] while sMVPS-random includes objects composed of random primitives from [60]. The objects were generated following the method of [39] with spatially varying Cook-Torrance BRDF. We render images from 20 viewpoints surrounding the object approximately every $18^{\circ}$ plus random jitter in position. For each view we render 10 randomly chosen directional light sources sampled uniformly on a $45^{\circ}$ spherical cap centered at the camera's optical axis. In addition to the images, we render ground truth normals, depth, albedo, and roughness. + +# 3.6. Training MVPSNet + +We train MVPSNet with supervised loss over surface normal and depth using the ground-truth created within synthetic sMVPS dataset. For each reference view, we use 2 source views. And we randomly choose 3 lights out of 10 to train our model. The total loss is defined as: + +$$ +L _ {m v p s} = \lambda_ {d} \cdot L _ {d} + \lambda_ {n} \cdot L _ {n}, \tag {10} +$$ + +$$ +L _ {d} = \sum_ {s = 1} ^ {3} \lambda_ {d s} \cdot L _ {d s}, \forall s = 1, 2, 3 \tag {11} +$$ + +where $L_{ds}$ and $L_{n}$ refer to the depth loss for scale $s$ and normal loss, respectively. For loss weights, we set $\lambda_{n} = 1$ and $\lambda_{d} = 10$ . The weights of each scale, $\lambda_{ds} = 1$ , for $s = 1,2,3$ . + +
Per-scene optimizationGeneralizable
CategoryManual EffortStandaloneSingle-view PSMVSMVPS
MethodPJ16 [47]LZ20 [34]BKW22 [29]BKC22 [27]PS-NeRF [61]PS- Transformer [24]CasMVSNet [21]- RTTransMVSNet [15]- RTOurs
BEAR2.540.731.011.010.763.171.471.480.80
BUDDHA1.120.972.681.150.864.091.261.101.07
COW1.140.391.090.760.753.041.271.050.77
POT23.210.671.541.400.763.051.461.050.82
READING1.300.661.970.840.923.600.750.760.66
AVERAGE1.860.691.661.030.813.391.241.090.82
Recon. Time/object--7 hrs?12 hrs?22s52s105s
+ +Table 2. L1 Chamfer Distance in mm (lower is better) between reconstructed mesh and GT after ICP. 'RT' denotes trained on our synthetic MVPS dataset. For non-manual methods, the best result is shown in bold, 2nd best as underline. LZ20 & PJ16 involve carefully crafted steps, manual efforts in finding correspondence, and an initial mesh or point cloud. + +
Per-scene optimizationGeneralizable
CategoryManual EffortStandaloneSingle-view PSMVSMVPS
MethodPJ16 [47]LZ20 [34]BKW22 [29]BKC22 [27]BKW23* [28]PS-NeRF [61]PS- Transformer [24]CasMVSNet [21]-RTTransMVSNet [15]-RTOurs
BEAR0.5510.9860.9280.9340.9650.9950.0780.9110.8820.991
BUDDHA0.9400.9360.6870.9260.9930.9830.0660.9190.9630.958
COW0.9180.9900.9370.9860.9870.9860.1400.9140.9410.993
POT20.4840.9850.9090.8890.9910.9910.1010.9010.9640.994
READING0.9050.9750.8100.9710.9750.9610.9610.9800.9780.988
AVERAGE0.7600.9740.8540.9410.9820.9830.2690.9250.9460.985
Recon. Time/object--7 hrs??12 hrs?22s52s105s
+ +Table 3. F-score with L2 distance and 1mm threshold (higher is better) between reconstructed mesh and GT after ICP. -RT' denotes trained on our synthetic MVPS dataset. For non-manual methods, the best result is shown in bold, 2nd best as underline. LZ20 & PJ16 involve carefully crafted steps, manual efforts in finding correspondence, and an initial mesh or point cloud. BKW23* code not available, results from the paper. + +# 4. Experiments + +Dataset. We evaluate our method and conduct ablation study on DiLiGenT-MV [34] dataset, which is the only benchmark dataset for MVPS tasks and widely used by all previous approaches. It contains images of 5 objects with diverse materials captured from 20 views. For each view, the object is illuminated by one of 96 calibrated point light sources at one time, which gives us 96 images with varying lighting conditions. + +Evaluation metrics. We evaluate the quality of recovered meshes using L1 Chamfer distance from PyTorch3D [33,48] and F-score [32] with L2 distance and 1mm threshold distance. The distances in both metrics are computed between the vertices of two meshes and the units are mm. + +Evaluation details. Ground truth meshes and meshes of PJ16 [47] and LZ20 [34] are included in the DiLiGenTMV dataset [34]. We thank the authors of BKW22 [29] and BKC22 [27] for providing us with their reconstructed meshes. For PS-NeRF [61] we use its publicly available mesh extraction code from stage 1 and unscale the extracted mesh to the scale of the ground truth as suggested in the code. The code or reconstructed meshes of BKW23 [28] was not released, so we only include their reported F-score + +on L2 distance in Table 3. To compare with PS-Transformer [24], we get normal maps from their pretrained model and integrate normals into depth maps, followed by a depth fusion step after rescaling all depth maps to the ground truth depth scales. To compare with CasMVSNet [21] and TransMVSNet [15], we consider both the pretrained models on DTU dataset [1] and models retrained on our synthetic dataset, dubbed as CasMVSNet-RT and TransMVSNet-RT. Images from 5 views are used to generate each single-view depth map and all 20 depth maps are fused together for 3D reconstruction. For ours, we take images from 5 views and 10 lightings conditions for each view, along with corresponding light directions, as input to generate single-view depth maps and all 20 depth maps are fused as other methods. Since there is no image showing the bottoms of objects in DiLiGenT-MV [34], following BKW22 [29] and BKC22 [27], we remove points that are located lower than $+5$ on the z-axis from all reconstructed meshes and the ground truth. Similar to most previous approaches [27, 29, 34, 47] we also perform a rigid registration using Iterative Closest Point (ICP) [2, 4, 12, 67] between the ground-truth and each reconstructed mesh for a fair comparison. + +![](images/b7358e50f9cc2649ba1d451cfdc3d4b64676127dd60e31b45c67178b20333f11.jpg) +Figure 3. Qualitative comparison of our method with existing approaches (red arrows highlight artifacts) and ablation studies. + +
MethodCasMVSNetCasMVSNet-RTOurs(train 1 light/view)Ours(train 3 light/view)
BEAR2.001.471.310.80
BUDDHA1.441.261.261.07
COW2.731.271.060.77
POT21.891.461.070.82
READING1.070.750.770.66
AVERAGE1.831.241.090.82
+ +Table 4. Ablation: Results are improved by retraining CasMVSNet [20] on proposed synthetic dataset (sMVPS). LAFM help in aggregating features across lighting variations, Ours (train 3 light/view) vs Ours (train 1 light/view), and is more accurate than CasMVSNet features, Ours (train 1 light/view) vs CasMVSNet-RT. + +# 4.1. Comparison with existing approaches + +We compare our algorithm with approaches that require per-scene optimization or training and with feed-forward generalizable methods. The quantitative result is shown in Table 2 and 3. We also show visual comparison of meshes from representative methods in Figure 3. + +(i) Per-scene Optimization. Per-Scene optimization methods can also be categorized into: +(a) Manual Efforts Needed. We compare with two traditional multi-stage MVPS methods, PJ16 [47] and LZ20 [34], which require manual efforts. We outperform PJ16 [47] with a clear margin. Although LZ20 [34] achieves better results than ours, note that both methods, PJ16 & LZ20, consist of multiple steps with carefully crafted geo- + +metric modeling. Besides, they require an initial mesh [47] or point cloud [34] to build upon and their performance is sensitive to the initialization quality. When the initialization step fails in large textureless regions, LZ20 [34] incorporates manual labeling to establish correspondence across views. In contrast, our pipeline is completely automatic without any manual efforts, does not involve any carefully crafted multi-stage approach, and does not require separate hyper-parameters for individual object. + +(b) Standalone Methods. Recent deep learning-based MVPS methods, including BKW22 [27], BKC22 [29], BKW23 [28] and PS-NeRF [61], are simpler and easier to adopt. However, like traditional methods [34, 47], they still optimize one model for each object individually, resulting in low computational efficiency. In contrast, although our model is trained only on synthetic data, we outperform some per-scene optimized methods [27, 29] and get comparable results as state-of-the-art, PS-NeRF [61]. Furthermore, even though PS-NeRF [61] recovers high-quality meshes with details, its recovered surfaces contain iso-contour pattern artifacts, e.g. see the red arrows in Fig. 3 on BUDDHA and COW, and sometimes incorrect shapes, e.g. READING. Note that, we could not report L1 Chamfer distance on BKW23 [28], since the code is unavailable, but we show in Table 3 that our method is slightly better than BKW23 on F-score. +(ii) Generalizable. We compare our method with two categories of generalizable methods: +(a) Single-view Photometric Stereo. PS-Transformer [24] is a state-of-the-art PS network, which takes multiple images with the same viewpoint but different lighting conditions as input and generates single-view normal map prediction. To get 3D reconstruction, we integrate each normal map into a depth map and fuse them together. Since the integrated depths are of arbitrary scale, we rescale them to the range of ground truth depth. Inherently, PS methods struggle with global shape modeling and it is challenging to stitch multi-view integrated depth of arbitrary scale, so PS-Transformer [24] doesn't perform well on full-view recovery. +(b) Multi-view Stereo. We also compare our method with CasMVSNet [21] and TransMVSNet [15], both of which use a single lighting image from each view. For fairness, we retrain both methods using our synthetic dataset with suggested hyper-parameters in original papers. We observe that lighting information can largely improve both accuracy and quality, quantitatively and qualitatively. On textureless objects, e.g. BEAR, and textureless regions, e.g. belly of BUDDHA, MVS alone gets noisy and rough surfaces. Moreover, our meshes have more high-frequency details that MVS alone may struggle with, e.g. the texture on POT2. This is because our LAFM are supervised with normal maps so they can learn the high-frequency components. + +# 4.2. Computational efficiency + +While our method outperforms some per-scene optimized methods [27, 29] and produces comparable results to state-of-the-arts [28, 61], the key advantage of our method is that it is fast, generalizable, and computationally efficient. Thus we analyze the inference time of the MVPS algorithms compared in this paper to the best of our abilities. + +- LZ20 [34]: This algorithm takes 117 minutes per object, without considering the time required for initializing a point cloud or any manual efforts. - BKW22 [29]: takes 7 hours to train per object. - BKC22 [27], BKW23 [28]: Since the authors did not mention the time required for training these algorithms it is not possible to provide an exact estimate. However, these approaches are based on MLPs, which take hours to train. - PS-NeRF [61]: takes 12 hours to train per object. - CasMVSNet [20]:, in contrast, takes only 22 seconds per object, including obtaining depth maps for each view using 5 views (1 reference view and 4 source views) and 1 lighting per view (5 images processed for estimating a depth map), fusing depth maps from all 20 views to a point cloud, computing normals for vertices in the point cloud and adopting Screened Poisson [31] to recover a mesh from the point cloud. - MVPSNet (Ours): takes a total of 105 seconds to create a mesh, including steps of obtaining depth maps for each view using 5 views (1 reference view and 4 source views) and 10 lightings per view (50 images processed in total), fusing depth maps from all 20 views to a point cloud, and adopting Screened Poisson [31] to recover a mesh from the point cloud. + +In summary, we are around $240\times$ faster than BKW22 [29] and around $411.4\times$ faster than PS-NeRF [61] ignoring their mesh extraction time. + +# 4.3. Ablation study + +The key contribution of this work includes: (a) our synthetic sMVPS dataset, including sMVPS-sculpture and sMVPS-random, and (b) 'Light Augmented Feature Maps' (LAFM) for more accurate mesh reconstruction. Here we design experiments to analyze impacts of these contributions. + +Synthetic Data (sMVPS-sculpture and sMVPS-random). To illustrate the effectiveness of our synthetic data, we evaluate the performance of a CasMVSNet [21] model trained on DTU dataset [1], and compare it with the CasMVSNet-RT model trained on our sMVPS dataset. The L1 Chamfer distance metric is reported in Table 4. We observe that training on our synthetic dataset improves reconstruction quality by $32.2\%$ , proving the effectiveness of our proposed data for MVPS reconstructions. See supplementary materials for comparison between pretrained TransMVSNet [15] and TransMVSNet-RT trained on our synthetic dataset. + +Light Augmented Feature Maps (LAFM). LAFM play + +
# of lightings141020304096
3 viewpoints1.2370.8830.8550.8630.8650.8710.892
5 viewpoints1.2440.8560.8230.8310.8400.8470.878
+ +Table 5. Averaged Chamfer-L1 distance (mm) of DiLiGenT-MV. The network is trained with 3 views and 3 lightings per view. + +two key roles in our approach: (i) they aggregate features from images captured with multiple lighting conditions but the same viewpoints, and (ii) they are trained with surface normal loss which helps to preserve high-frequency details in the features. The predicted surface normals are used to further refine the reconstructed mesh. + +For understanding the impact of (i), we train our proposed MVPSNet with just a single lighting image per view instead of 3 lightings. Thus LAFM are only aggregated across 1 image per view. In Table 4 we observe that using a single lighting per view ('Ours (train 1 light/view)') produces worse results (1.09 vs 0.82) than using 3 lightings per view ('Ours (train 3 light/view)'). However, even using a single lighting per view produces better performance than CasMVSNet-RT (1.09 vs 1.24), which is also trained on single lighting per view. This shows that LAFM are effective in both extracting accurate information from just a single image and aggregating shading information across multiple images with varying illumination. + +For understanding the impact of (ii), we train our proposed MVPSNet without any surface normal loss, 'Ours (w/o normal loss). We observe 'Ours (w/o normal loss)' is quantitatively comparable to 'Ours (w/normal loss)', 0.79 vs 0.82 in L1 chamfer distance and 0.985 vs 0.985 in F-score. However, in Fig. 3 we observe that the meshes produced by 'Ours (w/o normal loss)' are significantly noisier as shown with red arrows. + +# 4.4. Effects on different numbers of viewpoints and lighting conditions + +We also test the effects of the number of viewpoints and the number of lighting conditions used at inference time. The results of different combinations are shown in Table 5. We target at using sparse views to estimate depth maps, so we only test on 3 and 5 views. The results prove that although trained on 3 views, our model is able to utilize the extra information provided more views. For lighting conditions, the result gets better initially as images under more lighting conditions are provided, but then it gets slightly worse after around 10 lighting conditions. + +# 4.5. Result on real-world captures + +We include the result on real-world captures using a simple at-home setup, which requires no special equipment. As shown in Fig 4, a user captures MVPS imagery by attaching a flashlight with a string to the tripod to move lights in + +a circle around the camera. In our example, images from 5 viewpoints with 3 lighting conditions per view are captured. + +We automatically calibrate camera and lighting conditions using COLMAP [49, 50] and SDPSNet [8] separately. The room isn't strictly dark and contains some ambient lighting. We generate the foreground mask with an off-the-shelf segmentation algorithm. The result shows that our method produces good reconstruction and improves over CasMVSNet [20] in both details and global shapes. + +![](images/3a5134a584e674b95ae10235d0e4b0643041cebbba543b386fa6e85cc526151c.jpg) +Figure 4. Results of uncalibrated in-the-wild MVPS captures. + +![](images/abd62f8bb1edf6326e63237a3027ca5e728cec033b55a24dcec58a9573654d80.jpg) + +# 5. Conclusion + +In this work, we propose a fast and generalizable approach for MVPS. We introduce Light Aggregated Feature Maps that leverage shading cues from images with the same view under multiple lighting conditions to produce richer features in textureless regions. Being trained with normal estimation, LAFM also enable higher quality reconstruction than traditional MVS methods with only little compromise to speed. When trained on the synthetic sMVPS dataset we propose, our method produces results comparable to SOTA method that is about 400x slower at inference time. + +# References + +[1] Henrik Aanæs, Rasmus Ramsbøl Jensen, George Vogiatzis, Engin Tola, and Anders Bjorholm Dahl. Large-scale data for multiple-view stereopsis. International Journal of Computer Vision, 120:153-168, 2016. +[2] K. S. Arun, T. S. Huang, and S. D. Blostein. Least-squares fitting of two 3-d point sets. IEEE Transactions on Pattern Analysis and Machine Intelligence, PAMI-9(5):698-700, 1987. +[3] Meghna Asthana, William AP Smith, and Patrik Huber. Neural apparent brdf fields for multiview photometric stereo. arXiv preprint arXiv:2207.06793, 2022. +[4] Paul J Besl and Neil D McKay. Method for registration of 3-d shapes. In Sensor fusion IV: control paradigms and data structures, volume 1611, pages 586-606. Spie, 1992. + +[5] Michael Bleyer, Christoph Rhemann, and Carsten Rother. Patchmatch stereo-stereo matching with slanted support windows. In *Bmvc*, volume 11, pages 1-11, 2011. +[6] Mark Boss, Varun Jampani, Kihwan Kim, Hendrik P.A. Lensch, and Jan Kautz. Two-shot spatially-varying brdf and shape estimation. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2020. +[7] Chenjie Cao, Xinlin Ren, and Yanwei Fu. Mvsformer: Learning robust image representations via transformers and temperature-based depth for multi-view stereo. arXiv preprint arXiv:2208.02541, 2022. +[8] Guanying Chen, Kai Han, Boxin Shi, Yasuyuki Matsushita, and Kwan-Yee K Wong. Self-calibrating deep photometric stereo networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 8739-8747, 2019. +[9] Guanying Chen, Kai Han, Boxin Shi, Yasuyuki Matsushita, and Kwan-Yee Kenneth Wong. Deep photometric stereo for non-lambertian surfaces. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020. +[10] Guanying Chen, Kai Han, and Kwan-Yee K Wong. Ps-fcn: A flexible learning framework for photometric stereo. In Proceedings of the European Conference on Computer Vision (ECCV), pages 3-18, 2018. +[11] Guanying Chen, Michael Waechter, Boxin Shi, Kwan-Yee K Wong, and Yasuyuki Matsushita. What is learned in deep uncalibrated photometric stereo? In European Conference on Computer Vision, 2020. +[12] Yang Chen and Gérard Medioni. Object modelling by registration of multiple range images. Image and vision computing, 10(3):145-155, 1992. +[13] Robert T Collins. A space-sweep approach to true multi-image matching. In Proceedings CVPR IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 358-363. IEEE, 1996. +[14] Yikang Ding, Wentao Yuan, Qingtian Zhu, Haotian Zhang, Xiangyue Liu, Yuanjiang Wang, and Xiao Liu. Transmvsnet: Global context-aware multi-view stereo network with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8585-8594, 2022. +[15] Yikang Ding, Wentao Yuan, Qingtian Zhu, Haotian Zhang, Xiangyue Liu, Yuanjiang Wang, and Xiao Liu. Transmvsnet: Global context-aware multi-view stereo network with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8585-8594, 2022. +[16] Yasutaka Furukawa, Brian Curless, Steven M Seitz, and Richard Szeliski. Towards internet-scale multi-view stereo. In 2010 IEEE computer society conference on computer vision and pattern recognition, pages 1434-1441. IEEE, 2010. +[17] Yasutaka Furukawa and Jean Ponce. Accurate, dense, and robust multiview stereopsis. IEEE transactions on pattern analysis and machine intelligence, 32(8):1362-1376, 2009. +[18] Khang Truong Giang, Soohwan Song, and Sungho Jo. Curvature-guided dynamic scale networks for multi-view stereo. arXiv preprint arXiv:2112.05999, 2021. + +[19] Michael Goesele, Noah Snavely, Brian Curless, Hugues Hoppe, and Steven M Seitz. Multi-view stereo for community photo collections. In 2007 IEEE 11th International Conference on Computer Vision, pages 1-8. IEEE, 2007. +[20] Xiaodong Gu, Zhiwen Fan, Siyu Zhu, Zuozhuo Dai, Feitong Tan, and Ping Tan. Cascade cost volume for high-resolution multi-view stereo and stereo matching. 2019. +[21] Xiaodong Gu, Zhiwen Fan, Siyu Zhu, Zuozhuo Dai, Feitong Tan, and Ping Tan. Cascade cost volume for high-resolution multi-view stereo and stereo matching. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2495-2504, 2020. +[22] Carlos Hernandez, George Vogiatzis, and Roberto Cipolla. Multiview photometric stereo. IEEE Transactions on Pattern Analysis and Machine Intelligence, 30(3):548-554, 2008. +[23] Po-Han Huang, Kevin Matzen, Johannes Kopf, Narendra Ahuja, and Jia-Bin Huang. Deepmvs: Learning multi-view stereopsis. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 2821-2830, 2018. +[24] Satoshi Ikehata. Ps-transformer: Learning sparse photometric stereo network using self-attention mechanism. arXiv preprint arXiv:2211.11386, 2022. +[25] Mengqi Ji, Juergen Gall, Haitian Zheng, Yebin Liu, and Lu Fang. Surfacenet: An end-to-end 3d neural network for multiview stereopsis. In Proceedings of the IEEE International Conference on Computer Vision, pages 2307-2315, 2017. +[26] Sing Bing Kang, Richard Szeliski, and Jinxiang Chai. Handling occlusions in dense multi-view stereo. In Proceedings of the 2001 IEEE Computer Society Conference on Computer Vision and Pattern Recognition. CVPR 2001, volume 1, pages I-I. IEEE, 2001. +[27] Berk Kaya, Suryansh Kumar, Carlos Oliveira, Vittorio Ferrari, and Luc Van Gool. Uncertainty-aware deep multi-view photometric stereo. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12601-12611, 2022. +[28] Berk Kaya, Suryansh Kumar, Carlos Oliveira, Vittorio Ferrari, and Luc Van Gool. Multi-view photometric stereo revisited. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 3126-3135, 2023. +[29] Berk Kaya, Suryansh Kumar, Francesco Sarno, Vittorio Ferrari, and Luc Van Gool. Neural radiance fields approach to deep multi-view photometric stereo. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1965-1977, 2022. +[30] Michael Kazhdan, Matthew Bolitho, and Hugues Hoppe. Poisson surface reconstruction. In Proceedings of the fourth Eurographics symposium on Geometry processing, volume 7, page 0, 2006. +[31] Michael Kazhdan and Hugues Hoppe. Screened poisson surface reconstruction. ACM Transactions on Graphics (ToG), 32(3):1-13, 2013. +[32] Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: Benchmarking large-scale scene reconstruction. ACM Transactions on Graphics (ToG), 36(4):1-13, 2017. + +[33] Christoph Lassner and Michael Zollhöfer. Pulsar: Efficient sphere-based neural rendering. arXiv:2004.07484, 2020. +[34] Min Li, Zhenglong Zhou, Zhe Wu, Boxin Shi, Changyu Diao, and Ping Tan. Multi-view photometric stereo: A robust solution and benchmark dataset for spatially varying isotropic materials. IEEE Transactions on Image Processing, 29:4159-4173, 2020. +[35] Zhengqin Li, Zexiang Xu, Ravi Ramamoorthi, Kalyan Sunkavalli, and Manmohan Chandraker. Learning to reconstruct shape and spatially-varying reflectance from a single image. In SIGGRAPH Asia 2018 Technical Papers, page 269. ACM, 2018. +[36] Daniel Lichy, Soumyadip Sengupta, and David W Jacobs. Fast light-weight near-field photometric stereo. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12612-12621, 2022. +[37] Daniel Lichy, Soumyadip Sengupta, and David W. Jacobs. Fast light-weight near-field photometric stereo. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 12612-12621, June 2022. +[38] Daniel Lichy, Jiaye Wu, Soumyadip Sengupta, and David W. Jacobs. Shape and material capture at home. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 6123-6133, June 2021. +[39] Daniel Lichy, Jiaye Wu, Soumyadip Sengupta, and David W Jacobs. Shape and material capture at home. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6123-6133, 2021. +[40] William E Lorensen and Harvey E Cline. Marching cubes: A high resolution 3d surface construction algorithm. ACM siggraph computer graphics, 21(4):163-169, 1987. +[41] Keyang Luo, Tao Guan, Lili Ju, Haipeng Huang, and Yawei Luo. P-mvsnet: Learning patch-wise matching confidence aggregation for multi-view stereo. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10452-10461, 2019. +[42] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3d reconstruction in function space. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 4460-4470, 2019. +[43] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021. +[44] Diego Nehab, Szymon Rusinkiewicz, James Davis, and Ravi Ramamoorthi. Efficiently combining positions and normals for precise 3d geometry. ACM transactions on graphics (TOG), 24(3):536-543, 2005. +[45] Michael Oechsle, Songyou Peng, and Andreas Geiger. Unisurf: Unifying neural implicit surfaces and radiance fields for multi-view reconstruction. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 5589-5599, 2021. +[46] Jaesik Park, Sudipta N Sinha, Yasuyuki Matsushita, Yu-Wing Tai, and In So Kweon. Multiview photometric stereo + +using planar mesh parameterization. In Proceedings of the IEEE International Conference on Computer Vision, pages 1161-1168, 2013. +[47] Jaesik Park, Sudipta N Sinha, Yasuyuki Matsushita, Yu-Wing Tai, and In So Kweon. Robust multiview photometric stereo using planar mesh parameterization. IEEE transactions on pattern analysis and machine intelligence, 39(8):1591-1604, 2016. +[48] Nikhila Ravi, Jeremy Reizenstein, David Novotny, Taylor Gordon, Wan-Yen Lo, Justin Johnson, and Georgia Gkioxari. Accelerating 3d deep learning with pytorch3d. arXiv:2007.08501, 2020. +[49] Johannes L Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4104-4113, 2016. +[50] Johannes L Schonberger, Enliang Zheng, Jan-Michael Frahm, and Marc Pollefeys. Pixelwise view selection for unstructured multi-view stereo. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part III 14, pages 501-518. Springer, 2016. +[51] Soumyadip Sengupta, Angjoo Kanazawa, Carlos D Castillo, and David W Jacobs. Sfsnet: Learning shape, reflectance and illuminance of facesin the wild'. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 6296-6305, 2018. +[52] Boxin Shi, Zhe Wu Mo, Dinglong Duan, Sai-Kit Yeung, and Ping Tan. A benchmark dataset and evaluation for non-lambertian and uncalibrated photometric stereo. IEEE Trans. on Pattern Analysis and Machine Intelligence (TPAMI), 41(2):271-284, 2019. +[53] Pratul P Srinivasan, Boyang Deng, Xiuming Zhang, Matthew Tancik, Ben Mildenhall, and Jonathan T Barron. Nerv: Neural reflectance and visibility fields for relighting and view synthesis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7495-7504, 2021. +[54] Christoph Strecha, Rik Fransens, and Luc Van Gool. Wide-baseline stereo from multiple views: a probabilistic account. In Proceedings of the 2004 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 2004. CVPR 2004., volume 1, pages I-I. IEEE, 2004. +[55] Christoph Strecha, Rik Fransens, and Luc Van Gool. Combined depth and outlier estimation in multi-view stereo. In 2006 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'06), volume 2, pages 2394-2401. IEEE, 2006. +[56] Jiaming Sun, Yiming Xie, Linghao Chen, Xiaowei Zhou, and Hujun Bao. NeuralRecon: Real-time coherent 3D reconstruction from monocular video. CVPR, 2021. +[57] Olivia Wiles and Andrew Zisserman. Silnet: Single- and multi-view reconstruction by learning from silhouettes. In British Machine Vision Conference 2017, BMVC 2017, London, UK, September 4-7, 2017. BMVA Press, 2017. +[58] Robert J Woodham. Photometric method for determining surface orientation from multiple images. Optical engineering, 19(1):139-144, 1980. + +[59] Qingshan Xu and Wenbing Tao. Learning inverse depth regression for multi-view stereo with correlation cost volume. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 12508-12515, 2020. +[60] Zexiang Xu, Kalyan Sunkavalli, Sunil Hadap, and Ravi Ramamoorthi. Deep image-based relighting from optimal sparse samples. ACM Transactions on Graphics (TOG), 37(4):126, 2018. +[61] Wenqi Yang, Guanying Chen, Chaofeng Chen, Zhenfang Chen, and Kwan-Yee K Wong. Ps-nerf: Neural inverse rendering for multi-view photometric stereo. arXiv preprint arXiv:2207.11406, 2022. +[62] Yao Yao, Zixin Luo, Shiwei Li, Tian Fang, and Long Quan. Mvsnet: Depth inference for unstructured multi-view stereo. In Proceedings of the European conference on computer vision (ECCV), pages 767-783, 2018. +[63] Yao Yao, Zixin Luo, Shiwei Li, Tianwei Shen, Tian Fang, and Long Quan. Recurrent mvvsnet for high-resolution multiview stereo depth inference. Computer Vision and Pattern Recognition (CVPR), 2019. +[64] Lior Yariv, Yoni Kasten, Dror Moran, Meirav Galun, Matan Atzmon, Basri Ronen, and Yaron Lipman. Multiview neural surface reconstruction by disentangling geometry and appearance. Advances in Neural Information Processing Systems, 33:2492-2502, 2020. +[65] Kai Zhang, Fujun Luan, Qianqian Wang, Kavita Bala, and Noah Snavely. Physg: Inverse rendering with spherical gaussians for physics-based material editing and relighting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5453-5462, 2021. +[66] Xiuming Zhang, Pratul P Srinivasan, Boyang Deng, Paul Debevec, William T Freeman, and Jonathan T Barron. Nerfactor: Neural factorization of shape and reflectance under an unknown illumination. ACM Transactions on Graphics (TOG), 40(6):1-18, 2021. +[67] Zhengyou Zhang. Iterative point matching for registration of free-form curves and surfaces. International journal of computer vision, 13(2):119-152, 1994. +[68] Zhenglong Zhou, Zhe Wu, and Ping Tan. Multi-view photometric stereo with spatially varying isotropic materials. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1482-1489, 2013. \ No newline at end of file diff --git a/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/images.zip b/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..0d218cb5dd771ffb4cf12570149c88e42a983a10 --- /dev/null +++ b/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:9cb54107abc65b6d2538d7683220ea5d02ba093ace6a8ef847d147b1136d1a30 +size 572087 diff --git a/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/layout.json b/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..8b1a8b420436d0708db9be83f58ffbcfb1829424 --- /dev/null +++ b/2023/MVPSNet_ Fast Generalizable Multi-view Photometric Stereo/layout.json @@ -0,0 +1,9177 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 106, + 103, + 488, + 120 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 106, + 103, + 488, + 120 + ], + "spans": [ + { + "bbox": [ + 106, + 103, + 488, + 120 + ], + "type": "text", + "content": "MVPSNet: Fast Generalizable Multi-view Photometric Stereo" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 52, + 152, + 539, + 168 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 152, + 539, + 168 + ], + "spans": [ + { + "bbox": [ + 52, + 152, + 539, + 168 + ], + "type": "text", + "content": "Dongxu Zhao" + }, + { + "bbox": [ + 52, + 152, + 539, + 168 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 52, + 152, + 539, + 168 + ], + "type": "text", + "content": " Daniel Lichy" + }, + { + "bbox": [ + 52, + 152, + 539, + 168 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 152, + 539, + 168 + ], + "type": "text", + "content": " Pierre-Nicolas Perrin" + }, + { + "bbox": [ + 52, + 152, + 539, + 168 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 52, + 152, + 539, + 168 + ], + "type": "text", + "content": " Jan-Michael Frahm" + }, + { + "bbox": [ + 52, + 152, + 539, + 168 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 52, + 152, + 539, + 168 + ], + "type": "text", + "content": " Soumyadip Sengupta" + }, + { + "bbox": [ + 52, + 152, + 539, + 168 + ], + "type": "inline_equation", + "content": "^{1}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 88, + 176, + 504, + 191 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 88, + 176, + 504, + 191 + ], + "spans": [ + { + "bbox": [ + 88, + 176, + 504, + 191 + ], + "type": "text", + "content": "1University of North Carolina at Chapel Hill 2University of Maryland, College Park" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 125, + 193, + 468, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 125, + 193, + 468, + 205 + ], + "spans": [ + { + "bbox": [ + 125, + 193, + 468, + 205 + ], + "type": "text", + "content": "{dongxuzl, pnperrin, jmf, ronisen}@cs.unc.edu dlichy@umd.edu" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 143, + 241, + 192, + 254 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 241, + 192, + 254 + ], + "spans": [ + { + "bbox": [ + 143, + 241, + 192, + 254 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 45, + 266, + 289, + 457 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 266, + 289, + 457 + ], + "spans": [ + { + "bbox": [ + 45, + 266, + 289, + 457 + ], + "type": "text", + "content": "We propose a fast and generalizable solution to Multiview Photometric Stereo (MVPS), called MVPSNet. The key to our approach is a feature extraction network that effectively combines images from the same view captured under multiple lighting conditions to extract geometric features from shading cues for stereo matching. We demonstrate these features, termed 'Light Aggregated Feature Maps' (LAFM), are effective for feature matching even in textureless regions, where traditional multi-view stereo methods often fail. Our method produces similar reconstruction results to PS-NeRF, a state-of-the-art MVPS method that optimizes a neural network per-scene, while being " + }, + { + "bbox": [ + 45, + 266, + 289, + 457 + ], + "type": "inline_equation", + "content": "411 \\times" + }, + { + "bbox": [ + 45, + 266, + 289, + 457 + ], + "type": "text", + "content": " faster (105 seconds vs. 12 hours) in inference. Additionally, we introduce a new synthetic dataset for MVPS, sMVPS, which is shown to be effective for training a generalizable MVPS method." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 478, + 128, + 491 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 478, + 128, + 491 + ], + "spans": [ + { + "bbox": [ + 47, + 478, + 128, + 491 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 45, + 498, + 287, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 498, + 287, + 677 + ], + "spans": [ + { + "bbox": [ + 45, + 498, + 287, + 677 + ], + "type": "text", + "content": "3D reconstruction of an object can be achieved either through camera viewpoint variations, Multi-view Stereo (MVS), or by lighting direction variations, Photometric Stereo (PS). Both MVS and PS have relative strengths and weaknesses. While MVS succeeds in obtaining accurate global shapes, it suffers in textureless regions due to poor feature matching, often resulting in reconstructions that lack local details. On the other hand, PS produces accurate local details, even in textureless regions, by using shading information but fails to reconstruct accurate global shapes. In this paper, we focus on the problem of Multi-view Photometric Stereo (MVPS) where both camera viewpoint and lighting direction variations are used to accurately reconstruct global and local details of a 3D shape, even in textureless regions." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": "3D reconstruction techniques that produce high-quality results using only viewpoint variations (MVS) rely on test-time optimization, often by training neural networks per" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 241, + 547, + 433 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 241, + 547, + 433 + ], + "spans": [ + { + "bbox": [ + 304, + 241, + 547, + 433 + ], + "type": "text", + "content": "scene [53, 64, 66]. These methods are computationally inefficient, typically taking hours of computing time on a high-end GPU for each object. Existing MVs methods [20, 56, 62] that focus on computational efficiency employ feed-forward neural networks that are efficient but fail to produce high-quality details, especially in textureless regions. Existing MVPS approaches can produce high-quality reconstructions but require computationally inefficient per-scene training or optimization [27, 28, 29, 61]. Sometimes additional manual efforts and carefully crafted refinement steps are also needed [34, 47]. In contrast, we propose an efficient feed-forward neural architecture, MVPSNet, that can generalize to unseen objects and achieve similar reconstruction quality to that of per-scene optimization techniques while being computationally efficient during inference." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 435, + 547, + 579 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 435, + 547, + 579 + ], + "spans": [ + { + "bbox": [ + 304, + 435, + 547, + 579 + ], + "type": "text", + "content": "We design MVPSNet by taking inspiration from various deep MVS architectures [7, 14, 18, 20, 62] that are generalizable, computationally efficient, and can operate on high-resolution images. However, these approaches often fail in textureless regions, and their reconstructed meshes often lack details. We choose the CasMVsNet [20] architecture as our feature matching module, which has been repeatedly used by various MVS pipelines [7, 14, 18] for its simplicity and efficiency, and augment it to effectively incorporate lighting variation cues for better prediction of 3D shapes. In this way, we propose a feed-forward generalizable approach to Multi-view Photometric Stereo." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 582, + 548, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 548, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 548, + 715 + ], + "type": "text", + "content": "We introduce a multi-scale feature representation, called Light Aggregated Feature Maps (LAFM), whose role is to extract detailed geometric features from images by utilizing lighting variations. For brevity, we define Multi-light Images as a collection of images taken from the same viewpoint under different directional lighting conditions. Our intuition is that LAFM can efficiently aggregate shading patterns from multi-light images, by creating an 'artificial shading texture' in the textureless region. Multi-scale LAFM will then be used to construct a sequence of cost volumes to match features across sparse views in order to" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 493, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 493, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 493, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "12525" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 144 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 144 + ], + "type": "text", + "content": "predict a depth map for a reference view. We also predict surface normals from LAFM for each viewpoint, enabling LAFM to capture features related to high-frequency local details. The predicted surface normal can be used in addition to the depth maps to produce a more detailed mesh than using the depth maps alone." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 144, + 288, + 312 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 144, + 288, + 312 + ], + "spans": [ + { + "bbox": [ + 46, + 144, + 288, + 312 + ], + "type": "text", + "content": "To train the proposed MVPSNet architecture, we introduce a new synthetic MVPS dataset, sMVPS dataset. It consists of shapes from sculpture dataset [57] and random compositions of primitive shapes generated by [60]. We render these shapes with spatially varying Cook-Torrance BRDF under different camera viewpoints and lighting directions. We train MVPSNet on these rendered images with ground-truth supervision over predicted depth and surface normal maps. The trained model generalizes to real-world test scenes from DiLiGenT-MV [34] dataset. We show that simply re-training CasMVsNet on our dataset improves reconstruction quality over the pre-trained model on DiLiGenT-MV by " + }, + { + "bbox": [ + 46, + 144, + 288, + 312 + ], + "type": "inline_equation", + "content": "32\\%" + }, + { + "bbox": [ + 46, + 144, + 288, + 312 + ], + "type": "text", + "content": ", proving the effectiveness of our synthetic MVPS dataset for generalization." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 312, + 288, + 467 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 312, + 288, + 467 + ], + "spans": [ + { + "bbox": [ + 46, + 312, + 288, + 467 + ], + "type": "text", + "content": "We evaluate our approach on the only publicly available MVPS benchmark, the DiLiGenT-MV [34] dataset. Compared to the state-of-the-art MVPS technique, PS-NeRF [61], which optimizes a neural network per-scene, our proposed MVPSNet is " + }, + { + "bbox": [ + 46, + 312, + 288, + 467 + ], + "type": "inline_equation", + "content": "\\sim 411\\times" + }, + { + "bbox": [ + 46, + 312, + 288, + 467 + ], + "type": "text", + "content": " faster (105 seconds vs 12 hours) while producing similar reconstruction quality (L1 Chamfer distance of 0.82 vs 0.81, F-score on L2 distance of 0.985 vs 0.983). We further show that adding LAFM significantly improves reconstruction quality over CasMVSNet by " + }, + { + "bbox": [ + 46, + 312, + 288, + 467 + ], + "type": "inline_equation", + "content": "34\\%" + }, + { + "bbox": [ + 46, + 312, + 288, + 467 + ], + "type": "text", + "content": " in L1 Chamfer distance. We also observe that refining the reconstructed mesh derived from depth maps with predicted surface normals from LAFM improves reconstruction quality as shown in Fig 3." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 467, + 287, + 598 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 467, + 287, + 598 + ], + "spans": [ + { + "bbox": [ + 46, + 467, + 287, + 598 + ], + "type": "text", + "content": "In summary, the key contributions of this paper include: - Light Aggregated Feature Maps (LAFM) that can efficiently utilize multi-light images to extract detailed geometric features, especially in textureless regions. The surface normal predicted from LAFM also improves mesh reconstruction quality. - A synthetic MVPS dataset for training generalizable MVPS methods, which also improves Cas-MVSNet by " + }, + { + "bbox": [ + 46, + 467, + 287, + 598 + ], + "type": "inline_equation", + "content": "32\\%" + }, + { + "bbox": [ + 46, + 467, + 287, + 598 + ], + "type": "text", + "content": ". - A fast and generalizable Multi-view Photometric Stereo pipeline that is " + }, + { + "bbox": [ + 46, + 467, + 287, + 598 + ], + "type": "inline_equation", + "content": "411\\times" + }, + { + "bbox": [ + 46, + 467, + 287, + 598 + ], + "type": "text", + "content": " faster while producing similar reconstruction accuracy compared to state-of-the-art per-scene optimization approach [61]." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 609, + 132, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 609, + 132, + 623 + ], + "spans": [ + { + "bbox": [ + 47, + 609, + 132, + 623 + ], + "type": "text", + "content": "2. Related work" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 629, + 286, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 286, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 286, + 715 + ], + "type": "text", + "content": "Multi-view Stereo (MVS). MVS is a 3D reconstruction technique that utilizes multiple images captured from different viewpoints. While various techniques for MVS have been proposed, one commonly used approach that is relevant to our work involves constructing cost volumes similar to Plane Sweeping Algorithm [13] and then predicting per-view depth maps [21, 25, 41, 59, 62, 63] or disparity" + } + ] + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 312, + 70, + 541, + 138 + ], + "blocks": [ + { + "bbox": [ + 312, + 70, + 541, + 138 + ], + "lines": [ + { + "bbox": [ + 312, + 70, + 541, + 138 + ], + "spans": [ + { + "bbox": [ + 312, + 70, + 541, + 138 + ], + "type": "table", + "html": "
MethodGeneralizableMesh Reconstruction
PJ16 [47]XBase mesh+displacement map
LZ20 [34]X3D points+PSR [30]+Optimization [44]
BKW22 [29]XMLP+Marching Cube [40]
BKC22 [27]XMLP+Marching Cube [40]
PS-NeRF [61]XMLP+MISE [42]
BKW23 [28]XMLP+Marching Cube [40]
Ours✓3D Points+Screened Poisson [31]
", + "image_path": "49f252500429201f351fdbd5958129fcdf8924839e2bda44c49244466ef8821e.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 145, + 536, + 156 + ], + "lines": [ + { + "bbox": [ + 306, + 145, + 536, + 156 + ], + "spans": [ + { + "bbox": [ + 306, + 145, + 536, + 156 + ], + "type": "text", + "content": "Table 1. Comparison of our method with prior MVPS methods." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 181, + 545, + 276 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 181, + 545, + 276 + ], + "spans": [ + { + "bbox": [ + 304, + 181, + 545, + 276 + ], + "type": "text", + "content": "maps [23]. To create a cost volume, features are matched across neighboring viewpoints, and the quality of the features plays a critical role in the final reconstruction quality. Traditional methods [5, 16, 17, 19, 26, 50, 54, 55] use human-defined or hand-crafted image processing operators to extract feature maps. With recent advances in deep learning, features learned from deep neural networks have been proven to be effective." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 278, + 546, + 386 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 278, + 546, + 386 + ], + "spans": [ + { + "bbox": [ + 304, + 278, + 546, + 386 + ], + "type": "text", + "content": "The most relevant previous works are MVSNet [62] and its variations. MVSNet [62] uses homography to warp feature maps and a 3D CNN to regularize cost volumes. CasMVSNet [21] outperforms MVSNet in terms of accuracy and efficiency by building the 3D cost volume in a cascaded manner. TransMVSNet [15] builds upon CasMVSNet and adopts a transformer to consider intra-image and inter-image feature interactions, which further improves the results of CasMVSNet." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 388, + 546, + 532 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 388, + 546, + 532 + ], + "spans": [ + { + "bbox": [ + 304, + 388, + 546, + 532 + ], + "type": "text", + "content": "Photometric Stereo (PS). PS (introduced in [58]) uses lighting variation to reconstruct 3D shapes from a single viewpoint (see [52] for surveys). Calibrated PS approaches, like Chen et al. [10], train a neural network to predict surface normals using data with known lightings. Uncalibrated PS approaches [8, 9, 11] first predict the lighting parameters before solving for surface normals. While most PS works use a large number of images for inference, some use fewer [24, 38], or even one image [6, 35, 36, 51] (often called Shape from Shading). PS approaches are mostly based on feed-forward networks that generalize and can produce near real-time inference with low computational cost [37]." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 534, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 534, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 534, + 546, + 713 + ], + "type": "text", + "content": "Multi-view Photometric Stereo (MVPS). MVPS was initially proposed in [22] by combining PS with object silhouettes to reconstruct textureless shiny objects with fine details. However, this method only works well for specific parametric BRDF models [27]. Later, Li et al. [34, 68] propose to get iso-depth contours from PS images and sparse 3D points using structure-from-motion, which are propagated to recover a complete 3D shape. Park et al. [46, 47] use a planar mesh parameterization technique to parameterize a coarse mesh from MVS and take advantage of this 2D parameter domain to perform MVPS. Some of these traditional MVPS methods achieve high-quality results, but they require an initial 3D reconstruction and their performance is sensitive to it. Besides, they consist of multiple steps, so careful execution or expert interventions are often needed to" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "12526" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 62, + 70, + 197, + 264 + ], + "blocks": [ + { + "bbox": [ + 62, + 70, + 197, + 264 + ], + "lines": [ + { + "bbox": [ + 62, + 70, + 197, + 264 + ], + "spans": [ + { + "bbox": [ + 62, + 70, + 197, + 264 + ], + "type": "image", + "image_path": "6911031e21945bca173a6154e01d13dc53a995dc430952499b2012169efb6715.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 276, + 547, + 310 + ], + "lines": [ + { + "bbox": [ + 46, + 276, + 547, + 310 + ], + "spans": [ + { + "bbox": [ + 46, + 276, + 547, + 310 + ], + "type": "text", + "content": "Figure 1. Overview of our network architecture. (a) Light Informed Feature Extractor (LIFE) produces a multi-scale feature representation; (b) Light Aggregated Feature Maps (LAFM) Extractor aggregates these features across images of varying lighting conditions but same view; and (c) LAFM is used to create cost volumes and predict depth maps, similar to CasMVSNet [21], in addition to normal map." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 198, + 70, + 347, + 264 + ], + "blocks": [ + { + "bbox": [ + 198, + 70, + 347, + 264 + ], + "lines": [ + { + "bbox": [ + 198, + 70, + 347, + 264 + ], + "spans": [ + { + "bbox": [ + 198, + 70, + 347, + 264 + ], + "type": "image", + "image_path": "d95403bcd3b4219a6a8dce8c49c8505fe7927ee77ed320b502b3d0a23426d26d.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 347, + 70, + 533, + 264 + ], + "blocks": [ + { + "bbox": [ + 347, + 70, + 533, + 264 + ], + "lines": [ + { + "bbox": [ + 347, + 70, + 533, + 264 + ], + "spans": [ + { + "bbox": [ + 347, + 70, + 533, + 264 + ], + "type": "image", + "image_path": "49d73e923de6170f4d63a0b10ec766f3f63222806a5910c6638ebbc67d16d910.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 329, + 287, + 365 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 329, + 287, + 365 + ], + "spans": [ + { + "bbox": [ + 46, + 329, + 287, + 365 + ], + "type": "text", + "content": "get good results [34, 47]. In contrast, our proposed method trains a neural network end-to-end and the inference only requires one feed-forward pass of the trained network." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 378, + 289, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 378, + 289, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 378, + 289, + 713 + ], + "type": "text", + "content": "Recently, inspired by NeRF [43], various algorithms have been proposed that optimize a neural network perscene for MVPS. Kaya et al. [29] train a deep PS network first and condition the color rendering in NeRF [43] on normals predicted from PS. The reconstructed mesh, however, exhibits multiple artifacts. The authors in [27] propose to train a deep PS network and a deep MVS network extended with uncertainty estimation separately, and use these to fit the SDF represented by an MLP. To further enable reconstruction on anisotropic and glossy objects, Kaya et al. [28] add a neural volume rendering module to the SDF MLP in [27] to better fuse PS and MVS measurements. PS-NeRF [61] solves the task of jointly estimating the geometry, materials and lights. It first regularizes the gradient of a UNISURF [45] with estimated normals from PS, and then uses separate MLPs to explicitly model surface normal, BRDF, lights, and visibility which are optimized based on a shadow-aware differentiable rendering layer. Recent works have also used physically based differentiable rendering either inside a NeRF framework [3] or separately for optimization [65]. While per-scene optimization methods often generate precise reconstruction results, they have to optimize an individual model for each object separately, which is computationally inefficient. Thus, we propose a solution to Multi-view Photometric Stereo training on a new synthetic MVPS dataset, which is generalizable and can achieve similar results as SOTA per-scene optimization methods." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 328, + 394, + 342 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 328, + 394, + 342 + ], + "spans": [ + { + "bbox": [ + 306, + 328, + 394, + 342 + ], + "type": "text", + "content": "3. Our approach" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 348, + 397, + 361 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 348, + 397, + 361 + ], + "spans": [ + { + "bbox": [ + 306, + 348, + 397, + 361 + ], + "type": "text", + "content": "3.1. Problem setup" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 366, + 545, + 426 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 366, + 545, + 426 + ], + "spans": [ + { + "bbox": [ + 304, + 366, + 545, + 426 + ], + "type": "text", + "content": "We focus on the problem of calibrated multi-view photometric stereo, i.e. the locations of the light sources and the cameras are known a priori (calibrated prior to capture). The input data consists of a set of multi-light images of an object captured from multiple views." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "spans": [ + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "text", + "content": "Concretely, for the " + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "text", + "content": "-th view we have " + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "inline_equation", + "content": "M_{i}" + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "text", + "content": " images with varying lighting directions " + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "inline_equation", + "content": "l_{ij}" + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "text", + "content": ", denoted as " + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "inline_equation", + "content": "I_{ij}" + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "text", + "content": ". We refer to the collection " + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "inline_equation", + "content": "\\{I_{i1}, \\dots, I_{iM_i}\\}" + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "text", + "content": " as the multi-light images for the " + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "text", + "content": "-th view. For each view, we are given camera intrinsic matrix " + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "inline_equation", + "content": "K_{i}" + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "text", + "content": " and camera extrinsic parameters in the form of a rotation matrix, " + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "inline_equation", + "content": "R_{i}" + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "text", + "content": ", and a translation vector, " + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "inline_equation", + "content": "t_i" + }, + { + "bbox": [ + 304, + 426, + 546, + 521 + ], + "type": "text", + "content": ". Similar to virtually all MVS methods, we assume that we are provided with the depth range for each view." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 527, + 381, + 539 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 527, + 381, + 539 + ], + "spans": [ + { + "bbox": [ + 306, + 527, + 381, + 539 + ], + "type": "text", + "content": "3.2. Motivation" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 545, + 545, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 545, + 545, + 676 + ], + "spans": [ + { + "bbox": [ + 304, + 545, + 545, + 676 + ], + "type": "text", + "content": "Our approach follows a long line of work in Multi-view Stereo which uses Plane Sweep to construct a cost volume and predicts a depth map aligned with a reference image. Recent advances in Plane Sweep Stereo using deep neural networks, especially CasMVSNet [21], have proven to be generalizable across scenes and can predict high-resolution reconstruction in a matter of seconds. In contrast to previous Multi-view Photometric Stereo approaches, which optimize a neural network per scene, our goal is to produce a generalizable solution. Thus we aim to build upon the Plane Sweep stereo architecture proposed in CasMVSNet [21]." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 677, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 546, + 713 + ], + "type": "text", + "content": "CasMVSNet learns a deep image feature encoder for extracting representative features that can aid in feature matching across multiple views and create better cost vol" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "12527" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 133 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 133 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 133 + ], + "type": "text", + "content": "umes. However, these features are often ambiguous for non-textured regions and fail to preserve the geometric details. We believe incorporating lighting variations along with viewpoint variations can lead to better features, which in turn will produce better cost volumes and depth maps." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 133, + 287, + 276 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 133, + 287, + 276 + ], + "spans": [ + { + "bbox": [ + 46, + 133, + 287, + 276 + ], + "type": "text", + "content": "To this end, we introduce 'Light Aggregated Feature Maps' (LAFM), whose goal is to extract detailed geometric features, even for textureless regions, by jointly learning to aggregate feature maps over all images captured from a single viewpoint and multiple lighting directions. To obtain effective features that capture geometric details we use LAFM to regress surface normals. We show that LAFM provide superior information for stereo-matching than single-lighting feature maps (as used in CasMVSNet) and thus provide a better reconstruction. We also show that surface normals predicted using LAFM can be used during mesh reconstruction to improve quality over depth maps alone." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 277, + 288, + 469 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 277, + 288, + 469 + ], + "spans": [ + { + "bbox": [ + 46, + 277, + 288, + 469 + ], + "type": "text", + "content": "Our approach proceeds in three stages. We first extract multi-scale feature representation from each image, along with its lighting directions, using a shared neural network, 'Light Informed Feature Extractor' (LIFE). To aggregate features extracted by LIFE across all images under the same viewpoint but different lighting conditions, we use max-pooling operation. We can then create a cost volume for the reference view by matching LAFM of the reference view with all the LAFM from neighboring views. Finally, for each reference view, we predict a depth map using cost volume regularization and a surface normal map from the LAFM. We train our system in a multi-task learning framework with supervised losses over depth and normal predictions. In the following sections, we provide the details of our MVPSNet pipeline. An overview of MVPSNet architecture is illustrated in Figure 1." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 478, + 262, + 491 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 478, + 262, + 491 + ], + "spans": [ + { + "bbox": [ + 47, + 478, + 262, + 491 + ], + "type": "text", + "content": "3.3. Light Aggregated Feature Maps (LAFM)" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 497, + 287, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 497, + 287, + 700 + ], + "spans": [ + { + "bbox": [ + 46, + 497, + 287, + 700 + ], + "type": "text", + "content": "We introduce Light Aggregated Feature Maps (LAFM) that provide geometrically distinct multi-scale features for cost volume creation in a Plane Sweep Stereo approach. Our key observation is that the multi-light images provide us with important information for feature matching. For textureless regions, the variation in shading (including cast and attached shadows) created by different lighting directions can be interpreted as 'artificial' textures. Thus the role of LAFM for textureless regions is to capture the variation in shading as an 'artificial' texture that can be used for feature matching across different viewpoints. We also use LAFM to predict surface normal maps, enabling it to capture geometric details required for producing high-quality normal maps. Hence LAFM can capture better features for textureless regions and for reconstructing details, which were absent in the usual deep image features used in deep multi-view stereo algorithms." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 59, + 701, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 701, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 59, + 701, + 286, + 713 + ], + "type": "text", + "content": "We first define a multi-scale feature extractor, Light In" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": "formed Feature Extractor (LIFE), that takes an image " + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "I_{ij}" + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": " associated with its lighting direction " + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "l_{ij}" + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": " as input and produces feature maps at three different scales " + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "F_{ij}^{1}, F_{ij}^{2}, F_{ij}^{3}" + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": " at resolutions " + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "1/4, 1/2, 1" + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": " of the input resolution, and another feature map " + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "NF_{ij}" + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": " that will be used for normal prediction. The network architecture of LIFE is shown in Fig. 1(a) and will be discussed in details in the supplementary material." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 344, + 163, + 545, + 177 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 344, + 163, + 545, + 177 + ], + "spans": [ + { + "bbox": [ + 344, + 163, + 545, + 177 + ], + "type": "interline_equation", + "content": "N F _ {i j}, F _ {i j} ^ {1}, F _ {i j} ^ {2}, F _ {i j} ^ {3} = L I F E \\left(I _ {i j}, l _ {i j}; \\theta\\right) \\tag {1}", + "image_path": "8ba61edd10c2ccdc3f466d6576fddfd511c226c9ac47ad7ce1d948540955253d.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 176, + 545, + 200 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 176, + 545, + 200 + ], + "spans": [ + { + "bbox": [ + 304, + 176, + 545, + 200 + ], + "type": "text", + "content": "Note " + }, + { + "bbox": [ + 304, + 176, + 545, + 200 + ], + "type": "inline_equation", + "content": "l_{ij}" + }, + { + "bbox": [ + 304, + 176, + 545, + 200 + ], + "type": "text", + "content": " is of the same resolution as " + }, + { + "bbox": [ + 304, + 176, + 545, + 200 + ], + "type": "inline_equation", + "content": "I_{ij}" + }, + { + "bbox": [ + 304, + 176, + 545, + 200 + ], + "type": "text", + "content": " by simply repeating the same 3-dimensional lighting vector at each pixel." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 201, + 545, + 355 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 201, + 545, + 355 + ], + "spans": [ + { + "bbox": [ + 304, + 201, + 545, + 355 + ], + "type": "text", + "content": "Then we extract these multi-scale features for every image captured under the same viewpoint and different lighting conditions, " + }, + { + "bbox": [ + 304, + 201, + 545, + 355 + ], + "type": "inline_equation", + "content": "\\{I_{i1},\\dots,I_{iM_i}\\}" + }, + { + "bbox": [ + 304, + 201, + 545, + 355 + ], + "type": "text", + "content": ", using the same shared encoder LIFE. Let the feature maps obtained from these images be denoted as: " + }, + { + "bbox": [ + 304, + 201, + 545, + 355 + ], + "type": "inline_equation", + "content": "\\{NF_{ij},F_{ij}^{1},F_{ij}^{2},F_{ij}^{3}\\}" + }, + { + "bbox": [ + 304, + 201, + 545, + 355 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 201, + 545, + 355 + ], + "type": "inline_equation", + "content": "j = 1,\\dots,M_i" + }, + { + "bbox": [ + 304, + 201, + 545, + 355 + ], + "type": "text", + "content": ". We create 'Light Aggregated Feature Maps' (LAFM) from these multi-scale feature representations by performing a max-pooling operation for each scale. Pooling operations can handle various numbers of input feature maps and are order-agnostic. Moreover, max-pooling helps save the most prominent feature across all views and ignores non-activated features, which automatically handles shadows casted by directional lights [10]." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 367, + 356, + 545, + 374 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 367, + 356, + 545, + 374 + ], + "spans": [ + { + "bbox": [ + 367, + 356, + 545, + 374 + ], + "type": "interline_equation", + "content": "F _ {i} ^ {s} = \\max _ {j} F _ {i j} ^ {s}, \\quad \\forall s = 1, 2, 3 \\tag {2}", + "image_path": "6d773902725469b346b4f4ec5db44732f3d9c8974b9b9527c56e7dbdd0d272f1.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 361, + 377, + 545, + 395 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 361, + 377, + 545, + 395 + ], + "spans": [ + { + "bbox": [ + 361, + 377, + 545, + 395 + ], + "type": "interline_equation", + "content": "N F _ {i} = \\max _ {j} N F _ {i j}. \\tag {3}", + "image_path": "839f211292660ac835dbf316eb44d4d54c159799e9af50f58d1bfa38176e5664.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 395, + 545, + 418 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 395, + 545, + 418 + ], + "spans": [ + { + "bbox": [ + 306, + 395, + 545, + 418 + ], + "type": "text", + "content": "Thus for multi-light images we obtain LAFM as " + }, + { + "bbox": [ + 306, + 395, + 545, + 418 + ], + "type": "inline_equation", + "content": "LF_{i} = \\{NF_{i},F_{i}^{1},F_{i}^{2},F_{i}^{3}\\}" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 419, + 545, + 539 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 419, + 545, + 539 + ], + "spans": [ + { + "bbox": [ + 304, + 419, + 545, + 539 + ], + "type": "text", + "content": "The features at 3 scales " + }, + { + "bbox": [ + 304, + 419, + 545, + 539 + ], + "type": "inline_equation", + "content": "F_{i}^{1}, F_{i}^{2}, F_{i}^{3}" + }, + { + "bbox": [ + 304, + 419, + 545, + 539 + ], + "type": "text", + "content": " are then used to build cost volumes using differentiable homography warping, which we will talk about in detail in Section 3.4. The normal feature " + }, + { + "bbox": [ + 304, + 419, + 545, + 539 + ], + "type": "inline_equation", + "content": "NF_{i}" + }, + { + "bbox": [ + 304, + 419, + 545, + 539 + ], + "type": "text", + "content": " is fed into a lightweight normal regression network to predict per-view normal map, as shown in Figure 1(c). With the supervision from normal information and depth information, our LAFM benefit from the advantages of both MVS and PS which are good at global shape modeling and high-frequency component reconstruction, respectively." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 549, + 510, + 562 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 549, + 510, + 562 + ], + "spans": [ + { + "bbox": [ + 306, + 549, + 510, + 562 + ], + "type": "text", + "content": "3.4. Cost volume and depth map prediction" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 568, + 545, + 688 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 568, + 545, + 688 + ], + "spans": [ + { + "bbox": [ + 304, + 568, + 545, + 688 + ], + "type": "text", + "content": "Given Light Aggregated Feature Maps (LAFM), " + }, + { + "bbox": [ + 304, + 568, + 545, + 688 + ], + "type": "inline_equation", + "content": "LF_{i}" + }, + { + "bbox": [ + 304, + 568, + 545, + 688 + ], + "type": "text", + "content": " for each view " + }, + { + "bbox": [ + 304, + 568, + 545, + 688 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 568, + 545, + 688 + ], + "type": "text", + "content": ", we aim to build a cost volume for each reference view by selecting a set of source views with sufficient overlap. We adopt the multi-scale cost volume construction proposed in CasMVSNet [21], where the plane sweep is first performed at a low resolution and then at higher resolutions. Depth estimated from the previous step is used for generating depth proposals for the next step. Multi-scale cost volume reconstruction and depth map prediction follow the following steps." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "content": "Step 1: Depth hypothesis generation. We generate hypothesis depths for each pixel based on the lower resolution" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "12528" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 95 + ], + "type": "text", + "content": "depth estimated at the previous resolution. We store these in " + }, + { + "bbox": [ + 46, + 72, + 287, + 95 + ], + "type": "inline_equation", + "content": "h" + }, + { + "bbox": [ + 46, + 72, + 287, + 95 + ], + "type": "text", + "content": ", where" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 55, + 95, + 287, + 118 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 95, + 287, + 118 + ], + "spans": [ + { + "bbox": [ + 55, + 95, + 287, + 118 + ], + "type": "interline_equation", + "content": "h (u, v, w) = U p \\left(D ^ {s - 1}\\right) (u, v) + \\Delta_ {s} \\left(\\frac {w}{N _ {s} - 1} - \\frac {1}{2}\\right). \\tag {4}", + "image_path": "d2d947a2ba0f88114e59c8d9e17e487b9782a9473385568fc420ceafda279d8a.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "spans": [ + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "text", + "content": "Here " + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "inline_equation", + "content": "h(u,v,w)" + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "text", + "content": " is the " + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "text", + "content": "-th depth hypothesis at pixel " + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "inline_equation", + "content": "(u,v)" + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "inline_equation", + "content": "Up(D^{s - 1})" + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "text", + "content": " is the depth map at the previous lower resolution upsampled to the current resolution. " + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "inline_equation", + "content": "\\Delta_s" + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "text", + "content": " is the length of the depth interval we are searching at scale " + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "inline_equation", + "content": "N_{s}" + }, + { + "bbox": [ + 46, + 117, + 287, + 176 + ], + "type": "text", + "content": " is the number of hypothesis depths at the current scale." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "spans": [ + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "text", + "content": "Step 2: Cost volume construction. Building cost volume is a way of robustly searching for matches between a point " + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "inline_equation", + "content": "(u, v)" + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "text", + "content": " in the reference image " + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "inline_equation", + "content": "I_r" + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "text", + "content": " and a point on the corresponding epipolar line in the source image " + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "inline_equation", + "content": "I_{s_k}" + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "text", + "content": ". Concretely, consider a pixel " + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "inline_equation", + "content": "(u, v)" + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "text", + "content": " in the reference image. For every hypothesis depth " + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "text", + "content": ", we get a corresponding point in the source image on the epipolar line for " + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "inline_equation", + "content": "(u, v)" + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "text", + "content": ". We denote this point by " + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "inline_equation", + "content": "(u', v') = \\mathrm{warp}_{rs_k}(u, v, d)" + }, + { + "bbox": [ + 46, + 176, + 287, + 274 + ], + "type": "text", + "content": " where" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 58, + 275, + 287, + 312 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 275, + 287, + 312 + ], + "spans": [ + { + "bbox": [ + 58, + 275, + 287, + 312 + ], + "type": "interline_equation", + "content": "\\left[ \\begin{array}{l} u ^ {\\prime} \\\\ v ^ {\\prime} \\\\ 1 \\end{array} \\right] \\sim K _ {s _ {k}} R _ {s _ {k}} ^ {T} \\left[ \\left(R _ {r} K _ {r} ^ {- 1} d \\left[ \\begin{array}{l} u \\\\ v \\\\ 1 \\end{array} \\right] + t _ {r}\\right) - t _ {s} \\right]. \\tag {5}", + "image_path": "c2c05d9042b901069a4dec4e568d66870a907f8825a05517ead3185e94262148.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 59, + 315, + 218, + 326 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 315, + 218, + 326 + ], + "spans": [ + { + "bbox": [ + 59, + 315, + 218, + 326 + ], + "type": "text", + "content": "We then construct a per-image volume:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 71, + 326, + 287, + 339 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 326, + 287, + 339 + ], + "spans": [ + { + "bbox": [ + 71, + 326, + 287, + 339 + ], + "type": "interline_equation", + "content": "F _ {i} \\operatorname {v o l} _ {i} ^ {s} (u, v, w) = F _ {i} ^ {s} \\left(w a r p (u, v, h (u, v, w))\\right), \\tag {6}", + "image_path": "617e550f851c1001ab3dcf6ddade29ad970351e7516a6934687ccb36833ca7aa.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "spans": [ + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "type": "text", + "content": " runs over the reference and source views i.e. " + }, + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "type": "inline_equation", + "content": "i \\in \\{r, s_1, \\dots, s_k\\}" + }, + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "type": "text", + "content": ". These volumes are then aggregated into a single cost volume by taking their variance, which checks for the photo-consistency of the depth proposal " + }, + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "type": "text", + "content": " for pixel " + }, + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "type": "inline_equation", + "content": "(u, v)" + }, + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "type": "text", + "content": " in the reference image and the corresponding pixels in the warped sources images " + }, + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "type": "inline_equation", + "content": "s_k" + }, + { + "bbox": [ + 47, + 338, + 287, + 409 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 83, + 410, + 287, + 422 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 83, + 410, + 287, + 422 + ], + "spans": [ + { + "bbox": [ + 83, + 410, + 287, + 422 + ], + "type": "interline_equation", + "content": "\\operatorname {a g g} _ {-} \\operatorname {v o l} ^ {s} (u, v, w) = \\operatorname {v a r} _ {i} \\left(\\mathrm {F} _ {-} \\operatorname {v o l} (\\mathrm {u}, \\mathrm {v}, \\mathrm {w}) _ {i} ^ {s}\\right). \\tag {7}", + "image_path": "d867944ec1bb13f7441ae2c45bb541e01161eb82bf4eaf7764a885c4e4248d9c.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 422, + 287, + 458 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 422, + 287, + 458 + ], + "spans": [ + { + "bbox": [ + 46, + 422, + 287, + 458 + ], + "type": "text", + "content": "Step 3: Cost regularization. In this step we pass the aggregated volume through a 3D convolutional network and take a softmax to convert it to a match probability, using" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 77, + 458, + 287, + 470 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 77, + 458, + 287, + 470 + ], + "spans": [ + { + "bbox": [ + 77, + 458, + 287, + 470 + ], + "type": "interline_equation", + "content": "\\operatorname {p r o b} _ {-} \\operatorname {v o l} = \\operatorname {s o f t} _ {-} \\max _ {w} \\left(\\operatorname {r e g} _ {-} \\operatorname {n e t} ^ {s} \\left(\\operatorname {a g g} _ {-} \\operatorname {v o l} ^ {s}\\right)\\right). \\tag {8}", + "image_path": "4cc6065017566a25550c047f92d4ff6bdb8f3ebf4d15ebe2746832fabe35d397.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 470, + 287, + 517 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 470, + 287, + 517 + ], + "spans": [ + { + "bbox": [ + 46, + 470, + 287, + 517 + ], + "type": "text", + "content": "Step 4: Regression. We take the expectation of the hypothesis depths over the match probability given by the probability volume to obtain the depth at the current scale, which enables sub-pixel estimation." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 77, + 517, + 287, + 540 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 77, + 517, + 287, + 540 + ], + "spans": [ + { + "bbox": [ + 77, + 517, + 287, + 540 + ], + "type": "interline_equation", + "content": "D ^ {s} (u, v) = \\sum_ {w} \\operatorname {p r o b} _ {-} \\operatorname {v o l} (u, v, w) h (u, v, w). \\tag {9}", + "image_path": "8d1f9a1a580b7e522eda31d9ccb47de6cd3fb998bb2864376ccb9d7b56024e18.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 59, + 540, + 257, + 551 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 540, + 257, + 551 + ], + "spans": [ + { + "bbox": [ + 59, + 540, + 257, + 551 + ], + "type": "text", + "content": "This whole process is summarized in algorithm 1" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 563, + 190, + 574 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 563, + 190, + 574 + ], + "spans": [ + { + "bbox": [ + 48, + 563, + 190, + 574 + ], + "type": "text", + "content": "Algorithm 1 MVPSNet Algorithm" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 51, + 576, + 274, + 708 + ], + "type": "list", + "angle": 0, + "index": 26, + "blocks": [ + { + "bbox": [ + 53, + 576, + 220, + 590 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 576, + 220, + 590 + ], + "spans": [ + { + "bbox": [ + 53, + 576, + 220, + 590 + ], + "type": "text", + "content": "1: " + }, + { + "bbox": [ + 53, + 576, + 220, + 590 + ], + "type": "inline_equation", + "content": "NF_{ij},F_{ij}^{1},F_{ij}^{2},F_{ij}^{3} = \\mathrm{LIFE}(I_{ij},l_{ij};\\theta)" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 53, + 590, + 274, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 590, + 274, + 602 + ], + "spans": [ + { + "bbox": [ + 53, + 590, + 274, + 602 + ], + "type": "text", + "content": "2: " + }, + { + "bbox": [ + 53, + 590, + 274, + 602 + ], + "type": "inline_equation", + "content": "NF_{i} = \\max_{j}NF_{ij};F_{i}^{s} = \\max_{j}F_{ij}^{s}\\quad \\forall s = 1,2,3." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 53, + 602, + 206, + 613 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 602, + 206, + 613 + ], + "spans": [ + { + "bbox": [ + 53, + 602, + 206, + 613 + ], + "type": "text", + "content": "3: " + }, + { + "bbox": [ + 53, + 602, + 206, + 613 + ], + "type": "inline_equation", + "content": "N_{i} =" + }, + { + "bbox": [ + 53, + 602, + 206, + 613 + ], + "type": "text", + "content": " normal_regression_net " + }, + { + "bbox": [ + 53, + 602, + 206, + 613 + ], + "type": "inline_equation", + "content": "(NF_{i})" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 53, + 613, + 230, + 625 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 613, + 230, + 625 + ], + "spans": [ + { + "bbox": [ + 53, + 613, + 230, + 625 + ], + "type": "text", + "content": "4: " + }, + { + "bbox": [ + 53, + 613, + 230, + 625 + ], + "type": "inline_equation", + "content": "D^0 (u,v) = (\\max_{-}\\mathrm{depth} + \\min_{-}\\mathrm{depth}) / 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 53, + 626, + 133, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 626, + 133, + 635 + ], + "spans": [ + { + "bbox": [ + 53, + 626, + 133, + 635 + ], + "type": "text", + "content": "5: for " + }, + { + "bbox": [ + 53, + 626, + 133, + 635 + ], + "type": "inline_equation", + "content": "s = 1" + }, + { + "bbox": [ + 53, + 626, + 133, + 635 + ], + "type": "text", + "content": " to 3 do" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 53, + 636, + 271, + 651 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 636, + 271, + 651 + ], + "spans": [ + { + "bbox": [ + 53, + 636, + 271, + 651 + ], + "type": "text", + "content": "6: " + }, + { + "bbox": [ + 53, + 636, + 271, + 651 + ], + "type": "inline_equation", + "content": "h(u,v,w) = Up(D^{s - 1})(u,v) + \\Delta_s(\\frac{w}{N_s - 1} -\\frac{1}{2})" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 53, + 651, + 260, + 662 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 651, + 260, + 662 + ], + "spans": [ + { + "bbox": [ + 53, + 651, + 260, + 662 + ], + "type": "text", + "content": "7: " + }, + { + "bbox": [ + 53, + 651, + 260, + 662 + ], + "type": "inline_equation", + "content": "\\mathrm{F\\_vol}_i^s (u,v,w) = F_i^s (warp(u,v,h(u,\\bar{v},w)))" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 53, + 662, + 208, + 673 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 662, + 208, + 673 + ], + "spans": [ + { + "bbox": [ + 53, + 662, + 208, + 673 + ], + "type": "text", + "content": "8: " + }, + { + "bbox": [ + 53, + 662, + 208, + 673 + ], + "type": "inline_equation", + "content": "\\mathrm{agg\\_vol}^s (u,v,w) = \\mathrm{var}_i(\\mathrm{F\\_vol}_i^s)" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 53, + 673, + 246, + 685 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 673, + 246, + 685 + ], + "spans": [ + { + "bbox": [ + 53, + 673, + 246, + 685 + ], + "type": "text", + "content": "9: prob_vol = soft_max_w(reg_net^s(agg_vol^s))" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 52, + 685, + 254, + 697 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 685, + 254, + 697 + ], + "spans": [ + { + "bbox": [ + 52, + 685, + 254, + 697 + ], + "type": "text", + "content": "10: " + }, + { + "bbox": [ + 52, + 685, + 254, + 697 + ], + "type": "inline_equation", + "content": "D^{s}(u,v) = \\sum_{w}\\mathrm{prob\\_vol}(u,v,w)h(u,v,w)" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 51, + 698, + 97, + 708 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 698, + 97, + 708 + ], + "spans": [ + { + "bbox": [ + 51, + 698, + 97, + 708 + ], + "type": "text", + "content": "11: end for" + } + ] + } + ], + "index": 25 + } + ], + "sub_type": "ref_text" + }, + { + "type": "image", + "bbox": [ + 310, + 71, + 530, + 169 + ], + "blocks": [ + { + "bbox": [ + 310, + 71, + 530, + 169 + ], + "lines": [ + { + "bbox": [ + 310, + 71, + 530, + 169 + ], + "spans": [ + { + "bbox": [ + 310, + 71, + 530, + 169 + ], + "type": "image", + "image_path": "7f52ef90ed05c68cde359925a5676c48272332c0e235541284eef42d5954a149.jpg" + } + ] + } + ], + "index": 27, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 306, + 182, + 545, + 193 + ], + "lines": [ + { + "bbox": [ + 306, + 182, + 545, + 193 + ], + "spans": [ + { + "bbox": [ + 306, + 182, + 545, + 193 + ], + "type": "text", + "content": "Figure 2. Example images from proposed synthetic MVPS dataset." + } + ] + } + ], + "index": 28, + "angle": 0, + "type": "image_caption" + } + ], + "index": 27 + }, + { + "bbox": [ + 304, + 211, + 545, + 271 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 211, + 545, + 271 + ], + "spans": [ + { + "bbox": [ + 304, + 211, + 545, + 271 + ], + "type": "text", + "content": "Once we have depth and surface normal for each view, our mesh reconstruction pipeline consists of three steps: depth filtering, lifting depth and normal maps to a point cloud, and reconstructing the mesh using Screened Poisson [31] (See supplementary materials for details)." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 306, + 277, + 443, + 290 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 277, + 443, + 290 + ], + "spans": [ + { + "bbox": [ + 306, + 277, + 443, + 290 + ], + "type": "text", + "content": "3.5. Synthetic MVPS dataset" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 304, + 296, + 545, + 403 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 296, + 545, + 403 + ], + "spans": [ + { + "bbox": [ + 304, + 296, + 545, + 403 + ], + "type": "text", + "content": "A key component of our method is that we can learn better features for stereo matching, especially in textureless regions, by learning features that incorporate multi-lighting cues. However, there is no existing MVPS dataset that is large enough for neural network training. Therefore, we generate a large-scale synthetic dataset, sMVPS, consisting of two sub-datasets, sMVPS-sculpture (800 train scenes/4 test scenes) and sMVPS-random (1000 train scenes/20 test scenes)." + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 304, + 403, + 545, + 535 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 403, + 545, + 535 + ], + "spans": [ + { + "bbox": [ + 304, + 403, + 545, + 535 + ], + "type": "text", + "content": "sMVPS-sculpture consists of objects from the sculpture dataset [57] while sMVPS-random includes objects composed of random primitives from [60]. The objects were generated following the method of [39] with spatially varying Cook-Torrance BRDF. We render images from 20 viewpoints surrounding the object approximately every " + }, + { + "bbox": [ + 304, + 403, + 545, + 535 + ], + "type": "inline_equation", + "content": "18^{\\circ}" + }, + { + "bbox": [ + 304, + 403, + 545, + 535 + ], + "type": "text", + "content": " plus random jitter in position. For each view we render 10 randomly chosen directional light sources sampled uniformly on a " + }, + { + "bbox": [ + 304, + 403, + 545, + 535 + ], + "type": "inline_equation", + "content": "45^{\\circ}" + }, + { + "bbox": [ + 304, + 403, + 545, + 535 + ], + "type": "text", + "content": " spherical cap centered at the camera's optical axis. In addition to the images, we render ground truth normals, depth, albedo, and roughness." + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 306, + 541, + 420, + 554 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 541, + 420, + 554 + ], + "spans": [ + { + "bbox": [ + 306, + 541, + 420, + 554 + ], + "type": "text", + "content": "3.6. Training MVPSNet" + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 304, + 559, + 545, + 619 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 559, + 545, + 619 + ], + "spans": [ + { + "bbox": [ + 304, + 559, + 545, + 619 + ], + "type": "text", + "content": "We train MVPSNet with supervised loss over surface normal and depth using the ground-truth created within synthetic sMVPS dataset. For each reference view, we use 2 source views. And we randomly choose 3 lights out of 10 to train our model. The total loss is defined as:" + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 352, + 620, + 545, + 632 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 352, + 620, + 545, + 632 + ], + "spans": [ + { + "bbox": [ + 352, + 620, + 545, + 632 + ], + "type": "interline_equation", + "content": "L _ {m v p s} = \\lambda_ {d} \\cdot L _ {d} + \\lambda_ {n} \\cdot L _ {n}, \\tag {10}", + "image_path": "b01c92bff01ca855eec76db8eaa066f1a77695870b98c56ad9906f525699cdde.jpg" + } + ] + } + ], + "index": 35 + }, + { + "bbox": [ + 367, + 635, + 545, + 667 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 367, + 635, + 545, + 667 + ], + "spans": [ + { + "bbox": [ + 367, + 635, + 545, + 667 + ], + "type": "interline_equation", + "content": "L _ {d} = \\sum_ {s = 1} ^ {3} \\lambda_ {d s} \\cdot L _ {d s}, \\forall s = 1, 2, 3 \\tag {11}", + "image_path": "a908dfa1b80ff2e05f8f4f41bb466fe092b62e9e1cefe18573ac24d8bbe43923.jpg" + } + ] + } + ], + "index": 36 + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "inline_equation", + "content": "L_{ds}" + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "inline_equation", + "content": "L_{n}" + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "text", + "content": " refer to the depth loss for scale " + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "text", + "content": " and normal loss, respectively. For loss weights, we set " + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "inline_equation", + "content": "\\lambda_{n} = 1" + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "inline_equation", + "content": "\\lambda_{d} = 10" + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "text", + "content": ". The weights of each scale, " + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "inline_equation", + "content": "\\lambda_{ds} = 1" + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "text", + "content": ", for " + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "inline_equation", + "content": "s = 1,2,3" + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 37 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "12529" + } + ] + } + ], + "index": 38 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 51, + 70, + 542, + 184 + ], + "blocks": [ + { + "bbox": [ + 51, + 70, + 542, + 184 + ], + "lines": [ + { + "bbox": [ + 51, + 70, + 542, + 184 + ], + "spans": [ + { + "bbox": [ + 51, + 70, + 542, + 184 + ], + "type": "table", + "html": "
Per-scene optimizationGeneralizable
CategoryManual EffortStandaloneSingle-view PSMVSMVPS
MethodPJ16 [47]LZ20 [34]BKW22 [29]BKC22 [27]PS-NeRF [61]PS- Transformer [24]CasMVSNet [21]- RTTransMVSNet [15]- RTOurs
BEAR2.540.731.011.010.763.171.471.480.80
BUDDHA1.120.972.681.150.864.091.261.101.07
COW1.140.391.090.760.753.041.271.050.77
POT23.210.671.541.400.763.051.461.050.82
READING1.300.661.970.840.923.600.750.760.66
AVERAGE1.860.691.661.030.813.391.241.090.82
Recon. Time/object--7 hrs?12 hrs?22s52s105s
", + "image_path": "13a47b1ec3332ec8176d4ece34eeac8ec02c9017eaad6f334ee9495469b877b7.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 48, + 237, + 552, + 358 + ], + "blocks": [ + { + "bbox": [ + 48, + 192, + 546, + 225 + ], + "lines": [ + { + "bbox": [ + 48, + 192, + 546, + 225 + ], + "spans": [ + { + "bbox": [ + 48, + 192, + 546, + 225 + ], + "type": "text", + "content": "Table 2. L1 Chamfer Distance in mm (lower is better) between reconstructed mesh and GT after ICP. 'RT' denotes trained on our synthetic MVPS dataset. For non-manual methods, the best result is shown in bold, 2nd best as underline. LZ20 & PJ16 involve carefully crafted steps, manual efforts in finding correspondence, and an initial mesh or point cloud." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 237, + 552, + 358 + ], + "lines": [ + { + "bbox": [ + 48, + 237, + 552, + 358 + ], + "spans": [ + { + "bbox": [ + 48, + 237, + 552, + 358 + ], + "type": "table", + "html": "
Per-scene optimizationGeneralizable
CategoryManual EffortStandaloneSingle-view PSMVSMVPS
MethodPJ16 [47]LZ20 [34]BKW22 [29]BKC22 [27]BKW23* [28]PS-NeRF [61]PS- Transformer [24]CasMVSNet [21]-RTTransMVSNet [15]-RTOurs
BEAR0.5510.9860.9280.9340.9650.9950.0780.9110.8820.991
BUDDHA0.9400.9360.6870.9260.9930.9830.0660.9190.9630.958
COW0.9180.9900.9370.9860.9870.9860.1400.9140.9410.993
POT20.4840.9850.9090.8890.9910.9910.1010.9010.9640.994
READING0.9050.9750.8100.9710.9750.9610.9610.9800.9780.988
AVERAGE0.7600.9740.8540.9410.9820.9830.2690.9250.9460.985
Recon. Time/object--7 hrs??12 hrs?22s52s105s
", + "image_path": "fd73c5fab5567fc0c86b2c1287b1eed6dd4312257cf85fe755c4f0bd90bbd811.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 364, + 546, + 408 + ], + "lines": [ + { + "bbox": [ + 48, + 364, + 546, + 408 + ], + "spans": [ + { + "bbox": [ + 48, + 364, + 546, + 408 + ], + "type": "text", + "content": "Table 3. F-score with L2 distance and 1mm threshold (higher is better) between reconstructed mesh and GT after ICP. -RT' denotes trained on our synthetic MVPS dataset. For non-manual methods, the best result is shown in bold, 2nd best as underline. LZ20 & PJ16 involve carefully crafted steps, manual efforts in finding correspondence, and an initial mesh or point cloud. BKW23* code not available, results from the paper." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 49, + 427, + 127, + 440 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 427, + 127, + 440 + ], + "spans": [ + { + "bbox": [ + 49, + 427, + 127, + 440 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 448, + 286, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 448, + 286, + 544 + ], + "spans": [ + { + "bbox": [ + 48, + 448, + 286, + 544 + ], + "type": "text", + "content": "Dataset. We evaluate our method and conduct ablation study on DiLiGenT-MV [34] dataset, which is the only benchmark dataset for MVPS tasks and widely used by all previous approaches. It contains images of 5 objects with diverse materials captured from 20 views. For each view, the object is illuminated by one of 96 calibrated point light sources at one time, which gives us 96 images with varying lighting conditions." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 544, + 286, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 544, + 286, + 604 + ], + "spans": [ + { + "bbox": [ + 48, + 544, + 286, + 604 + ], + "type": "text", + "content": "Evaluation metrics. We evaluate the quality of recovered meshes using L1 Chamfer distance from PyTorch3D [33,48] and F-score [32] with L2 distance and 1mm threshold distance. The distances in both metrics are computed between the vertices of two meshes and the units are mm." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 605, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 605, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 605, + 286, + 713 + ], + "type": "text", + "content": "Evaluation details. Ground truth meshes and meshes of PJ16 [47] and LZ20 [34] are included in the DiLiGenTMV dataset [34]. We thank the authors of BKW22 [29] and BKC22 [27] for providing us with their reconstructed meshes. For PS-NeRF [61] we use its publicly available mesh extraction code from stage 1 and unscale the extracted mesh to the scale of the ground truth as suggested in the code. The code or reconstructed meshes of BKW23 [28] was not released, so we only include their reported F-score" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 307, + 427, + 545, + 691 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 427, + 545, + 691 + ], + "spans": [ + { + "bbox": [ + 307, + 427, + 545, + 691 + ], + "type": "text", + "content": "on L2 distance in Table 3. To compare with PS-Transformer [24], we get normal maps from their pretrained model and integrate normals into depth maps, followed by a depth fusion step after rescaling all depth maps to the ground truth depth scales. To compare with CasMVSNet [21] and TransMVSNet [15], we consider both the pretrained models on DTU dataset [1] and models retrained on our synthetic dataset, dubbed as CasMVSNet-RT and TransMVSNet-RT. Images from 5 views are used to generate each single-view depth map and all 20 depth maps are fused together for 3D reconstruction. For ours, we take images from 5 views and 10 lightings conditions for each view, along with corresponding light directions, as input to generate single-view depth maps and all 20 depth maps are fused as other methods. Since there is no image showing the bottoms of objects in DiLiGenT-MV [34], following BKW22 [29] and BKC22 [27], we remove points that are located lower than " + }, + { + "bbox": [ + 307, + 427, + 545, + 691 + ], + "type": "inline_equation", + "content": "+5" + }, + { + "bbox": [ + 307, + 427, + 545, + 691 + ], + "type": "text", + "content": " on the z-axis from all reconstructed meshes and the ground truth. Similar to most previous approaches [27, 29, 34, 47] we also perform a rigid registration using Iterative Closest Point (ICP) [2, 4, 12, 67] between the ground-truth and each reconstructed mesh for a fair comparison." + } + ] + } + ], + "index": 8 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 750, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 750, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 750, + 317, + 757 + ], + "type": "text", + "content": "12530" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 56, + 71, + 544, + 510 + ], + "blocks": [ + { + "bbox": [ + 56, + 71, + 544, + 510 + ], + "lines": [ + { + "bbox": [ + 56, + 71, + 544, + 510 + ], + "spans": [ + { + "bbox": [ + 56, + 71, + 544, + 510 + ], + "type": "image", + "image_path": "b7358e50f9cc2649ba1d451cfdc3d4b64676127dd60e31b45c67178b20333f11.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 69, + 515, + 523, + 526 + ], + "lines": [ + { + "bbox": [ + 69, + 515, + 523, + 526 + ], + "spans": [ + { + "bbox": [ + 69, + 515, + 523, + 526 + ], + "type": "text", + "content": "Figure 3. Qualitative comparison of our method with existing approaches (red arrows highlight artifacts) and ablation studies." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 53, + 529, + 281, + 622 + ], + "blocks": [ + { + "bbox": [ + 53, + 529, + 281, + 622 + ], + "lines": [ + { + "bbox": [ + 53, + 529, + 281, + 622 + ], + "spans": [ + { + "bbox": [ + 53, + 529, + 281, + 622 + ], + "type": "table", + "html": "
MethodCasMVSNetCasMVSNet-RTOurs(train 1 light/view)Ours(train 3 light/view)
BEAR2.001.471.310.80
BUDDHA1.441.261.261.07
COW2.731.271.060.77
POT21.891.461.070.82
READING1.070.750.770.66
AVERAGE1.831.241.090.82
", + "image_path": "87e65c0db4fe9ab90dc99a499cc3269318b4d346fced512954c093814cbb4675.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 631, + 287, + 696 + ], + "lines": [ + { + "bbox": [ + 46, + 631, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 631, + 287, + 696 + ], + "type": "text", + "content": "Table 4. Ablation: Results are improved by retraining CasMVSNet [20] on proposed synthetic dataset (sMVPS). LAFM help in aggregating features across lighting variations, Ours (train 3 light/view) vs Ours (train 1 light/view), and is more accurate than CasMVSNet features, Ours (train 1 light/view) vs CasMVSNet-RT." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 530, + 504, + 544 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 530, + 504, + 544 + ], + "spans": [ + { + "bbox": [ + 306, + 530, + 504, + 544 + ], + "type": "text", + "content": "4.1. Comparison with existing approaches" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 553, + 545, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 553, + 545, + 613 + ], + "spans": [ + { + "bbox": [ + 304, + 553, + 545, + 613 + ], + "type": "text", + "content": "We compare our algorithm with approaches that require per-scene optimization or training and with feed-forward generalizable methods. The quantitative result is shown in Table 2 and 3. We also show visual comparison of meshes from representative methods in Figure 3." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 618, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 8, + "blocks": [ + { + "bbox": [ + 304, + 618, + 545, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 618, + 545, + 641 + ], + "spans": [ + { + "bbox": [ + 304, + 618, + 545, + 641 + ], + "type": "text", + "content": "(i) Per-scene Optimization. Per-Scene optimization methods can also be categorized into:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": "(a) Manual Efforts Needed. We compare with two traditional multi-stage MVPS methods, PJ16 [47] and LZ20 [34], which require manual efforts. We outperform PJ16 [47] with a clear margin. Although LZ20 [34] achieves better results than ours, note that both methods, PJ16 & LZ20, consist of multiple steps with carefully crafted geo-" + } + ] + } + ], + "index": 7 + } + ], + "sub_type": "text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "12531" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 180 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 180 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 180 + ], + "type": "text", + "content": "metric modeling. Besides, they require an initial mesh [47] or point cloud [34] to build upon and their performance is sensitive to the initialization quality. When the initialization step fails in large textureless regions, LZ20 [34] incorporates manual labeling to establish correspondence across views. In contrast, our pipeline is completely automatic without any manual efforts, does not involve any carefully crafted multi-stage approach, and does not require separate hyper-parameters for individual object." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 182, + 289, + 714 + ], + "type": "list", + "angle": 0, + "index": 5, + "blocks": [ + { + "bbox": [ + 46, + 182, + 289, + 385 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 182, + 289, + 385 + ], + "spans": [ + { + "bbox": [ + 46, + 182, + 289, + 385 + ], + "type": "text", + "content": "(b) Standalone Methods. Recent deep learning-based MVPS methods, including BKW22 [27], BKC22 [29], BKW23 [28] and PS-NeRF [61], are simpler and easier to adopt. However, like traditional methods [34, 47], they still optimize one model for each object individually, resulting in low computational efficiency. In contrast, although our model is trained only on synthetic data, we outperform some per-scene optimized methods [27, 29] and get comparable results as state-of-the-art, PS-NeRF [61]. Furthermore, even though PS-NeRF [61] recovers high-quality meshes with details, its recovered surfaces contain iso-contour pattern artifacts, e.g. see the red arrows in Fig. 3 on BUDDHA and COW, and sometimes incorrect shapes, e.g. READING. Note that, we could not report L1 Chamfer distance on BKW23 [28], since the code is unavailable, but we show in Table 3 that our method is slightly better than BKW23 on F-score." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 388, + 287, + 411 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 388, + 287, + 411 + ], + "spans": [ + { + "bbox": [ + 47, + 388, + 287, + 411 + ], + "type": "text", + "content": "(ii) Generalizable. We compare our method with two categories of generalizable methods:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 411, + 287, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 411, + 287, + 555 + ], + "spans": [ + { + "bbox": [ + 46, + 411, + 287, + 555 + ], + "type": "text", + "content": "(a) Single-view Photometric Stereo. PS-Transformer [24] is a state-of-the-art PS network, which takes multiple images with the same viewpoint but different lighting conditions as input and generates single-view normal map prediction. To get 3D reconstruction, we integrate each normal map into a depth map and fuse them together. Since the integrated depths are of arbitrary scale, we rescale them to the range of ground truth depth. Inherently, PS methods struggle with global shape modeling and it is challenging to stitch multi-view integrated depth of arbitrary scale, so PS-Transformer [24] doesn't perform well on full-view recovery." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 557, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 557, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 557, + 288, + 714 + ], + "type": "text", + "content": "(b) Multi-view Stereo. We also compare our method with CasMVSNet [21] and TransMVSNet [15], both of which use a single lighting image from each view. For fairness, we retrain both methods using our synthetic dataset with suggested hyper-parameters in original papers. We observe that lighting information can largely improve both accuracy and quality, quantitatively and qualitatively. On textureless objects, e.g. BEAR, and textureless regions, e.g. belly of BUDDHA, MVS alone gets noisy and rough surfaces. Moreover, our meshes have more high-frequency details that MVS alone may struggle with, e.g. the texture on POT2. This is because our LAFM are supervised with normal maps so they can learn the high-frequency components." + } + ] + } + ], + "index": 4 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 72, + 446, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 446, + 85 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 446, + 85 + ], + "type": "text", + "content": "4.2. Computational efficiency" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 90, + 545, + 162 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 90, + 545, + 162 + ], + "spans": [ + { + "bbox": [ + 304, + 90, + 545, + 162 + ], + "type": "text", + "content": "While our method outperforms some per-scene optimized methods [27, 29] and produces comparable results to state-of-the-arts [28, 61], the key advantage of our method is that it is fast, generalizable, and computationally efficient. Thus we analyze the inference time of the MVPS algorithms compared in this paper to the best of our abilities." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 163, + 546, + 424 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 163, + 546, + 424 + ], + "spans": [ + { + "bbox": [ + 304, + 163, + 546, + 424 + ], + "type": "text", + "content": "- LZ20 [34]: This algorithm takes 117 minutes per object, without considering the time required for initializing a point cloud or any manual efforts. - BKW22 [29]: takes 7 hours to train per object. - BKC22 [27], BKW23 [28]: Since the authors did not mention the time required for training these algorithms it is not possible to provide an exact estimate. However, these approaches are based on MLPs, which take hours to train. - PS-NeRF [61]: takes 12 hours to train per object. - CasMVSNet [20]:, in contrast, takes only 22 seconds per object, including obtaining depth maps for each view using 5 views (1 reference view and 4 source views) and 1 lighting per view (5 images processed for estimating a depth map), fusing depth maps from all 20 views to a point cloud, computing normals for vertices in the point cloud and adopting Screened Poisson [31] to recover a mesh from the point cloud. - MVPSNet (Ours): takes a total of 105 seconds to create a mesh, including steps of obtaining depth maps for each view using 5 views (1 reference view and 4 source views) and 10 lightings per view (50 images processed in total), fusing depth maps from all 20 views to a point cloud, and adopting Screened Poisson [31] to recover a mesh from the point cloud." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 425, + 545, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 425, + 545, + 460 + ], + "spans": [ + { + "bbox": [ + 305, + 425, + 545, + 460 + ], + "type": "text", + "content": "In summary, we are around " + }, + { + "bbox": [ + 305, + 425, + 545, + 460 + ], + "type": "inline_equation", + "content": "240\\times" + }, + { + "bbox": [ + 305, + 425, + 545, + 460 + ], + "type": "text", + "content": " faster than BKW22 [29] and around " + }, + { + "bbox": [ + 305, + 425, + 545, + 460 + ], + "type": "inline_equation", + "content": "411.4\\times" + }, + { + "bbox": [ + 305, + 425, + 545, + 460 + ], + "type": "text", + "content": " faster than PS-NeRF [61] ignoring their mesh extraction time." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 468, + 397, + 480 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 468, + 397, + 480 + ], + "spans": [ + { + "bbox": [ + 306, + 468, + 397, + 480 + ], + "type": "text", + "content": "4.3. Ablation study" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 486, + 545, + 556 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 486, + 545, + 556 + ], + "spans": [ + { + "bbox": [ + 304, + 486, + 545, + 556 + ], + "type": "text", + "content": "The key contribution of this work includes: (a) our synthetic sMVPS dataset, including sMVPS-sculpture and sMVPS-random, and (b) 'Light Augmented Feature Maps' (LAFM) for more accurate mesh reconstruction. Here we design experiments to analyze impacts of these contributions." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 558, + 545, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 545, + 700 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 545, + 700 + ], + "type": "text", + "content": "Synthetic Data (sMVPS-sculpture and sMVPS-random). To illustrate the effectiveness of our synthetic data, we evaluate the performance of a CasMVSNet [21] model trained on DTU dataset [1], and compare it with the CasMVSNet-RT model trained on our sMVPS dataset. The L1 Chamfer distance metric is reported in Table 4. We observe that training on our synthetic dataset improves reconstruction quality by " + }, + { + "bbox": [ + 304, + 558, + 545, + 700 + ], + "type": "inline_equation", + "content": "32.2\\%" + }, + { + "bbox": [ + 304, + 558, + 545, + 700 + ], + "type": "text", + "content": ", proving the effectiveness of our proposed data for MVPS reconstructions. See supplementary materials for comparison between pretrained TransMVSNet [15] and TransMVSNet-RT trained on our synthetic dataset." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "type": "text", + "content": "Light Augmented Feature Maps (LAFM). LAFM play" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "12532" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 56, + 71, + 279, + 107 + ], + "blocks": [ + { + "bbox": [ + 56, + 71, + 279, + 107 + ], + "lines": [ + { + "bbox": [ + 56, + 71, + 279, + 107 + ], + "spans": [ + { + "bbox": [ + 56, + 71, + 279, + 107 + ], + "type": "table", + "html": "
# of lightings141020304096
3 viewpoints1.2370.8830.8550.8630.8650.8710.892
5 viewpoints1.2440.8560.8230.8310.8400.8470.878
", + "image_path": "20b838ee429b093a37875e55078ba8c08657b2e5d3042307c9cd13ac78222d0d.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 114, + 287, + 138 + ], + "lines": [ + { + "bbox": [ + 47, + 114, + 287, + 138 + ], + "spans": [ + { + "bbox": [ + 47, + 114, + 287, + 138 + ], + "type": "text", + "content": "Table 5. Averaged Chamfer-L1 distance (mm) of DiLiGenT-MV. The network is trained with 3 views and 3 lightings per view." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 157, + 287, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 157, + 287, + 228 + ], + "spans": [ + { + "bbox": [ + 46, + 157, + 287, + 228 + ], + "type": "text", + "content": "two key roles in our approach: (i) they aggregate features from images captured with multiple lighting conditions but the same viewpoints, and (ii) they are trained with surface normal loss which helps to preserve high-frequency details in the features. The predicted surface normals are used to further refine the reconstructed mesh." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 229, + 287, + 385 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 229, + 287, + 385 + ], + "spans": [ + { + "bbox": [ + 46, + 229, + 287, + 385 + ], + "type": "text", + "content": "For understanding the impact of (i), we train our proposed MVPSNet with just a single lighting image per view instead of 3 lightings. Thus LAFM are only aggregated across 1 image per view. In Table 4 we observe that using a single lighting per view ('Ours (train 1 light/view)') produces worse results (1.09 vs 0.82) than using 3 lightings per view ('Ours (train 3 light/view)'). However, even using a single lighting per view produces better performance than CasMVSNet-RT (1.09 vs 1.24), which is also trained on single lighting per view. This shows that LAFM are effective in both extracting accurate information from just a single image and aggregating shading information across multiple images with varying illumination." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 385, + 287, + 482 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 385, + 287, + 482 + ], + "spans": [ + { + "bbox": [ + 46, + 385, + 287, + 482 + ], + "type": "text", + "content": "For understanding the impact of (ii), we train our proposed MVPSNet without any surface normal loss, 'Ours (w/o normal loss). We observe 'Ours (w/o normal loss)' is quantitatively comparable to 'Ours (w/normal loss)', 0.79 vs 0.82 in L1 chamfer distance and 0.985 vs 0.985 in F-score. However, in Fig. 3 we observe that the meshes produced by 'Ours (w/o normal loss)' are significantly noisier as shown with red arrows." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 489, + 287, + 514 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 489, + 287, + 514 + ], + "spans": [ + { + "bbox": [ + 47, + 489, + 287, + 514 + ], + "type": "text", + "content": "4.4. Effects on different numbers of viewpoints and lighting conditions" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 519, + 287, + 639 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 519, + 287, + 639 + ], + "spans": [ + { + "bbox": [ + 46, + 519, + 287, + 639 + ], + "type": "text", + "content": "We also test the effects of the number of viewpoints and the number of lighting conditions used at inference time. The results of different combinations are shown in Table 5. We target at using sparse views to estimate depth maps, so we only test on 3 and 5 views. The results prove that although trained on 3 views, our model is able to utilize the extra information provided more views. For lighting conditions, the result gets better initially as images under more lighting conditions are provided, but then it gets slightly worse after around 10 lighting conditions." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 647, + 209, + 661 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 647, + 209, + 661 + ], + "spans": [ + { + "bbox": [ + 47, + 647, + 209, + 661 + ], + "type": "text", + "content": "4.5. Result on real-world captures" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 665, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 287, + 715 + ], + "type": "text", + "content": "We include the result on real-world captures using a simple at-home setup, which requires no special equipment. As shown in Fig 4, a user captures MVPS imagery by attaching a flashlight with a string to the tripod to move lights in" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 72, + 545, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 96 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 96 + ], + "type": "text", + "content": "a circle around the camera. In our example, images from 5 viewpoints with 3 lighting conditions per view are captured." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 98, + 547, + 182 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 98, + 547, + 182 + ], + "spans": [ + { + "bbox": [ + 304, + 98, + 547, + 182 + ], + "type": "text", + "content": "We automatically calibrate camera and lighting conditions using COLMAP [49, 50] and SDPSNet [8] separately. The room isn't strictly dark and contains some ambient lighting. We generate the foreground mask with an off-the-shelf segmentation algorithm. The result shows that our method produces good reconstruction and improves over CasMVSNet [20] in both details and global shapes." + } + ] + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 324, + 194, + 439, + 334 + ], + "blocks": [ + { + "bbox": [ + 324, + 194, + 439, + 334 + ], + "lines": [ + { + "bbox": [ + 324, + 194, + 439, + 334 + ], + "spans": [ + { + "bbox": [ + 324, + 194, + 439, + 334 + ], + "type": "image", + "image_path": "3a5134a584e674b95ae10235d0e4b0643041cebbba543b386fa6e85cc526151c.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 306, + 335, + 529, + 346 + ], + "lines": [ + { + "bbox": [ + 306, + 335, + 529, + 346 + ], + "spans": [ + { + "bbox": [ + 306, + 335, + 529, + 346 + ], + "type": "text", + "content": "Figure 4. Results of uncalibrated in-the-wild MVPS captures." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 440, + 194, + 529, + 334 + ], + "blocks": [ + { + "bbox": [ + 440, + 194, + 529, + 334 + ], + "lines": [ + { + "bbox": [ + 440, + 194, + 529, + 334 + ], + "spans": [ + { + "bbox": [ + 440, + 194, + 529, + 334 + ], + "type": "image", + "image_path": "abd62f8bb1edf6326e63237a3027ca5e728cec033b55a24dcec58a9573654d80.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 375, + 379, + 388 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 375, + 379, + 388 + ], + "spans": [ + { + "bbox": [ + 306, + 375, + 379, + 388 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 396, + 545, + 515 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 396, + 545, + 515 + ], + "spans": [ + { + "bbox": [ + 304, + 396, + 545, + 515 + ], + "type": "text", + "content": "In this work, we propose a fast and generalizable approach for MVPS. We introduce Light Aggregated Feature Maps that leverage shading cues from images with the same view under multiple lighting conditions to produce richer features in textureless regions. Being trained with normal estimation, LAFM also enable higher quality reconstruction than traditional MVS methods with only little compromise to speed. When trained on the synthetic sMVPS dataset we propose, our method produces results comparable to SOTA method that is about 400x slower at inference time." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 531, + 365, + 544 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 531, + 365, + 544 + ], + "spans": [ + { + "bbox": [ + 306, + 531, + 365, + 544 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 310, + 552, + 547, + 714 + ], + "type": "list", + "angle": 0, + "index": 21, + "blocks": [ + { + "bbox": [ + 310, + 552, + 545, + 596 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 552, + 545, + 596 + ], + "spans": [ + { + "bbox": [ + 310, + 552, + 545, + 596 + ], + "type": "text", + "content": "[1] Henrik Aanæs, Rasmus Ramsbøl Jensen, George Vogiatzis, Engin Tola, and Anders Bjorholm Dahl. Large-scale data for multiple-view stereopsis. International Journal of Computer Vision, 120:153-168, 2016." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 311, + 598, + 547, + 642 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 598, + 547, + 642 + ], + "spans": [ + { + "bbox": [ + 311, + 598, + 547, + 642 + ], + "type": "text", + "content": "[2] K. S. Arun, T. S. Huang, and S. D. Blostein. Least-squares fitting of two 3-d point sets. IEEE Transactions on Pattern Analysis and Machine Intelligence, PAMI-9(5):698-700, 1987." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 311, + 644, + 545, + 677 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 644, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 311, + 644, + 545, + 677 + ], + "type": "text", + "content": "[3] Meghna Asthana, William AP Smith, and Patrik Huber. Neural apparent brdf fields for multiview photometric stereo. arXiv preprint arXiv:2207.06793, 2022." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 311, + 680, + 547, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 680, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 311, + 680, + 547, + 714 + ], + "type": "text", + "content": "[4] Paul J Besl and Neil D McKay. Method for registration of 3-d shapes. In Sensor fusion IV: control paradigms and data structures, volume 1611, pages 586-606. Spie, 1992." + } + ] + } + ], + "index": 20 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "12533" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 286, + 712 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 53, + 72, + 286, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 72, + 286, + 106 + ], + "spans": [ + { + "bbox": [ + 53, + 72, + 286, + 106 + ], + "type": "text", + "content": "[5] Michael Bleyer, Christoph Rhemann, and Carsten Rother. Patchmatch stereo-stereo matching with slanted support windows. In *Bmvc*, volume 11, pages 1-11, 2011." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 53, + 107, + 286, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 107, + 286, + 150 + ], + "spans": [ + { + "bbox": [ + 53, + 107, + 286, + 150 + ], + "type": "text", + "content": "[6] Mark Boss, Varun Jampani, Kihwan Kim, Hendrik P.A. Lensch, and Jan Kautz. Two-shot spatially-varying brdf and shape estimation. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2020." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 152, + 286, + 196 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 152, + 286, + 196 + ], + "spans": [ + { + "bbox": [ + 53, + 152, + 286, + 196 + ], + "type": "text", + "content": "[7] Chenjie Cao, Xinlin Ren, and Yanwei Fu. Mvsformer: Learning robust image representations via transformers and temperature-based depth for multi-view stereo. arXiv preprint arXiv:2208.02541, 2022." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 198, + 286, + 251 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 198, + 286, + 251 + ], + "spans": [ + { + "bbox": [ + 53, + 198, + 286, + 251 + ], + "type": "text", + "content": "[8] Guanying Chen, Kai Han, Boxin Shi, Yasuyuki Matsushita, and Kwan-Yee K Wong. Self-calibrating deep photometric stereo networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 8739-8747, 2019." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 253, + 286, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 253, + 286, + 297 + ], + "spans": [ + { + "bbox": [ + 53, + 253, + 286, + 297 + ], + "type": "text", + "content": "[9] Guanying Chen, Kai Han, Boxin Shi, Yasuyuki Matsushita, and Kwan-Yee Kenneth Wong. Deep photometric stereo for non-lambertian surfaces. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 298, + 286, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 298, + 286, + 342 + ], + "spans": [ + { + "bbox": [ + 48, + 298, + 286, + 342 + ], + "type": "text", + "content": "[10] Guanying Chen, Kai Han, and Kwan-Yee K Wong. Ps-fcn: A flexible learning framework for photometric stereo. In Proceedings of the European Conference on Computer Vision (ECCV), pages 3-18, 2018." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 343, + 286, + 387 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 343, + 286, + 387 + ], + "spans": [ + { + "bbox": [ + 48, + 343, + 286, + 387 + ], + "type": "text", + "content": "[11] Guanying Chen, Michael Waechter, Boxin Shi, Kwan-Yee K Wong, and Yasuyuki Matsushita. What is learned in deep uncalibrated photometric stereo? In European Conference on Computer Vision, 2020." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 388, + 286, + 421 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 388, + 286, + 421 + ], + "spans": [ + { + "bbox": [ + 48, + 388, + 286, + 421 + ], + "type": "text", + "content": "[12] Yang Chen and Gérard Medioni. Object modelling by registration of multiple range images. Image and vision computing, 10(3):145-155, 1992." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 422, + 286, + 466 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 422, + 286, + 466 + ], + "spans": [ + { + "bbox": [ + 48, + 422, + 286, + 466 + ], + "type": "text", + "content": "[13] Robert T Collins. A space-sweep approach to true multi-image matching. In Proceedings CVPR IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 358-363. IEEE, 1996." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 468, + 286, + 532 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 468, + 286, + 532 + ], + "spans": [ + { + "bbox": [ + 48, + 468, + 286, + 532 + ], + "type": "text", + "content": "[14] Yikang Ding, Wentao Yuan, Qingtian Zhu, Haotian Zhang, Xiangyue Liu, Yuanjiang Wang, and Xiao Liu. Transmvsnet: Global context-aware multi-view stereo network with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8585-8594, 2022." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 534, + 286, + 599 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 534, + 286, + 599 + ], + "spans": [ + { + "bbox": [ + 48, + 534, + 286, + 599 + ], + "type": "text", + "content": "[15] Yikang Ding, Wentao Yuan, Qingtian Zhu, Haotian Zhang, Xiangyue Liu, Yuanjiang Wang, and Xiao Liu. Transmvsnet: Global context-aware multi-view stereo network with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8585-8594, 2022." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 601, + 286, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 601, + 286, + 645 + ], + "spans": [ + { + "bbox": [ + 48, + 601, + 286, + 645 + ], + "type": "text", + "content": "[16] Yasutaka Furukawa, Brian Curless, Steven M Seitz, and Richard Szeliski. Towards internet-scale multi-view stereo. In 2010 IEEE computer society conference on computer vision and pattern recognition, pages 1434-1441. IEEE, 2010." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 647, + 286, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 286, + 678 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 286, + 678 + ], + "type": "text", + "content": "[17] Yasutaka Furukawa and Jean Ponce. Accurate, dense, and robust multiview stereopsis. IEEE transactions on pattern analysis and machine intelligence, 32(8):1362-1376, 2009." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 680, + 286, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 680, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 680, + 286, + 712 + ], + "type": "text", + "content": "[18] Khang Truong Giang, Soohwan Song, and Sungho Jo. Curvature-guided dynamic scale networks for multi-view stereo. arXiv preprint arXiv:2112.05999, 2021." + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 117 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 117 + ], + "type": "text", + "content": "[19] Michael Goesele, Noah Snavely, Brian Curless, Hugues Hoppe, and Steven M Seitz. Multi-view stereo for community photo collections. In 2007 IEEE 11th International Conference on Computer Vision, pages 1-8. IEEE, 2007." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 119, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 119, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 119, + 545, + 150 + ], + "type": "text", + "content": "[20] Xiaodong Gu, Zhiwen Fan, Siyu Zhu, Zuozhuo Dai, Feitong Tan, and Ping Tan. Cascade cost volume for high-resolution multi-view stereo and stereo matching. 2019." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 152, + 545, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 206 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 206 + ], + "type": "text", + "content": "[21] Xiaodong Gu, Zhiwen Fan, Siyu Zhu, Zuozhuo Dai, Feitong Tan, and Ping Tan. Cascade cost volume for high-resolution multi-view stereo and stereo matching. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2495-2504, 2020." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 209, + 545, + 240 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 209, + 545, + 240 + ], + "spans": [ + { + "bbox": [ + 307, + 209, + 545, + 240 + ], + "type": "text", + "content": "[22] Carlos Hernandez, George Vogiatzis, and Roberto Cipolla. Multiview photometric stereo. IEEE Transactions on Pattern Analysis and Machine Intelligence, 30(3):548-554, 2008." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 243, + 545, + 296 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 243, + 545, + 296 + ], + "spans": [ + { + "bbox": [ + 307, + 243, + 545, + 296 + ], + "type": "text", + "content": "[23] Po-Han Huang, Kevin Matzen, Johannes Kopf, Narendra Ahuja, and Jia-Bin Huang. Deepmvs: Learning multi-view stereopsis. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 2821-2830, 2018." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 298, + 545, + 331 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 298, + 545, + 331 + ], + "spans": [ + { + "bbox": [ + 307, + 298, + 545, + 331 + ], + "type": "text", + "content": "[24] Satoshi Ikehata. Ps-transformer: Learning sparse photometric stereo network using self-attention mechanism. arXiv preprint arXiv:2211.11386, 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 333, + 545, + 376 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 333, + 545, + 376 + ], + "spans": [ + { + "bbox": [ + 307, + 333, + 545, + 376 + ], + "type": "text", + "content": "[25] Mengqi Ji, Juergen Gall, Haitian Zheng, Yebin Liu, and Lu Fang. Surfacenet: An end-to-end 3d neural network for multiview stereopsis. In Proceedings of the IEEE International Conference on Computer Vision, pages 2307-2315, 2017." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 377, + 545, + 431 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 377, + 545, + 431 + ], + "spans": [ + { + "bbox": [ + 307, + 377, + 545, + 431 + ], + "type": "text", + "content": "[26] Sing Bing Kang, Richard Szeliski, and Jinxiang Chai. Handling occlusions in dense multi-view stereo. In Proceedings of the 2001 IEEE Computer Society Conference on Computer Vision and Pattern Recognition. CVPR 2001, volume 1, pages I-I. IEEE, 2001." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 434, + 545, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 434, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 307, + 434, + 545, + 487 + ], + "type": "text", + "content": "[27] Berk Kaya, Suryansh Kumar, Carlos Oliveira, Vittorio Ferrari, and Luc Van Gool. Uncertainty-aware deep multi-view photometric stereo. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12601-12611, 2022." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 490, + 545, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 490, + 545, + 533 + ], + "spans": [ + { + "bbox": [ + 307, + 490, + 545, + 533 + ], + "type": "text", + "content": "[28] Berk Kaya, Suryansh Kumar, Carlos Oliveira, Vittorio Ferrari, and Luc Van Gool. Multi-view photometric stereo revisited. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 3126-3135, 2023." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 535, + 545, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 535, + 545, + 588 + ], + "spans": [ + { + "bbox": [ + 307, + 535, + 545, + 588 + ], + "type": "text", + "content": "[29] Berk Kaya, Suryansh Kumar, Francesco Sarno, Vittorio Ferrari, and Luc Van Gool. Neural radiance fields approach to deep multi-view photometric stereo. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1965-1977, 2022." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 590, + 545, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 590, + 545, + 634 + ], + "spans": [ + { + "bbox": [ + 307, + 590, + 545, + 634 + ], + "type": "text", + "content": "[30] Michael Kazhdan, Matthew Bolitho, and Hugues Hoppe. Poisson surface reconstruction. In Proceedings of the fourth Eurographics symposium on Geometry processing, volume 7, page 0, 2006." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 635, + 545, + 667 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 635, + 545, + 667 + ], + "spans": [ + { + "bbox": [ + 307, + 635, + 545, + 667 + ], + "type": "text", + "content": "[31] Michael Kazhdan and Hugues Hoppe. Screened poisson surface reconstruction. ACM Transactions on Graphics (ToG), 32(3):1-13, 2013." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 670, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 670, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 670, + 545, + 712 + ], + "type": "text", + "content": "[32] Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: Benchmarking large-scale scene reconstruction. ACM Transactions on Graphics (ToG), 36(4):1-13, 2017." + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "12534" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 95 + ], + "type": "text", + "content": "[33] Christoph Lassner and Michael Zollhöfer. Pulsar: Efficient sphere-based neural rendering. arXiv:2004.07484, 2020." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 151 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 151 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 151 + ], + "type": "text", + "content": "[34] Min Li, Zhenglong Zhou, Zhe Wu, Boxin Shi, Changyu Diao, and Ping Tan. Multi-view photometric stereo: A robust solution and benchmark dataset for spatially varying isotropic materials. IEEE Transactions on Image Processing, 29:4159-4173, 2020." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 152, + 287, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 152, + 287, + 206 + ], + "spans": [ + { + "bbox": [ + 48, + 152, + 287, + 206 + ], + "type": "text", + "content": "[35] Zhengqin Li, Zexiang Xu, Ravi Ramamoorthi, Kalyan Sunkavalli, and Manmohan Chandraker. Learning to reconstruct shape and spatially-varying reflectance from a single image. In SIGGRAPH Asia 2018 Technical Papers, page 269. ACM, 2018." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 208, + 287, + 252 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 208, + 287, + 252 + ], + "spans": [ + { + "bbox": [ + 48, + 208, + 287, + 252 + ], + "type": "text", + "content": "[36] Daniel Lichy, Soumyadip Sengupta, and David W Jacobs. Fast light-weight near-field photometric stereo. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12612-12621, 2022." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 254, + 287, + 307 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 254, + 287, + 307 + ], + "spans": [ + { + "bbox": [ + 48, + 254, + 287, + 307 + ], + "type": "text", + "content": "[37] Daniel Lichy, Soumyadip Sengupta, and David W. Jacobs. Fast light-weight near-field photometric stereo. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 12612-12621, June 2022." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 309, + 287, + 353 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 309, + 287, + 353 + ], + "spans": [ + { + "bbox": [ + 48, + 309, + 287, + 353 + ], + "type": "text", + "content": "[38] Daniel Lichy, Jiaye Wu, Soumyadip Sengupta, and David W. Jacobs. Shape and material capture at home. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 6123-6133, June 2021." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 354, + 287, + 398 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 354, + 287, + 398 + ], + "spans": [ + { + "bbox": [ + 48, + 354, + 287, + 398 + ], + "type": "text", + "content": "[39] Daniel Lichy, Jiaye Wu, Soumyadip Sengupta, and David W Jacobs. Shape and material capture at home. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6123-6133, 2021." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 399, + 287, + 432 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 399, + 287, + 432 + ], + "spans": [ + { + "bbox": [ + 48, + 399, + 287, + 432 + ], + "type": "text", + "content": "[40] William E Lorensen and Harvey E Cline. Marching cubes: A high resolution 3d surface construction algorithm. ACM siggraph computer graphics, 21(4):163-169, 1987." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 434, + 287, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 434, + 287, + 487 + ], + "spans": [ + { + "bbox": [ + 48, + 434, + 287, + 487 + ], + "type": "text", + "content": "[41] Keyang Luo, Tao Guan, Lili Ju, Haipeng Huang, and Yawei Luo. P-mvsnet: Learning patch-wise matching confidence aggregation for multi-view stereo. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10452-10461, 2019." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 490, + 287, + 544 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 490, + 287, + 544 + ], + "spans": [ + { + "bbox": [ + 48, + 490, + 287, + 544 + ], + "type": "text", + "content": "[42] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3d reconstruction in function space. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 4460-4470, 2019." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 545, + 287, + 589 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 545, + 287, + 589 + ], + "spans": [ + { + "bbox": [ + 48, + 545, + 287, + 589 + ], + "type": "text", + "content": "[43] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 590, + 287, + 633 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 590, + 287, + 633 + ], + "spans": [ + { + "bbox": [ + 48, + 590, + 287, + 633 + ], + "type": "text", + "content": "[44] Diego Nehab, Szymon Rusinkiewicz, James Davis, and Ravi Ramamoorthi. Efficiently combining positions and normals for precise 3d geometry. ACM transactions on graphics (TOG), 24(3):536-543, 2005." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 635, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 635, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 635, + 287, + 689 + ], + "type": "text", + "content": "[45] Michael Oechsle, Songyou Peng, and Andreas Geiger. Unisurf: Unifying neural implicit surfaces and radiance fields for multi-view reconstruction. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 5589-5599, 2021." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "text", + "content": "[46] Jaesik Park, Sudipta N Sinha, Yasuyuki Matsushita, Yu-Wing Tai, and In So Kweon. Multiview photometric stereo" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 105 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 105 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 105 + ], + "type": "text", + "content": "using planar mesh parameterization. In Proceedings of the IEEE International Conference on Computer Vision, pages 1161-1168, 2013." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 106, + 545, + 160 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 106, + 545, + 160 + ], + "spans": [ + { + "bbox": [ + 307, + 106, + 545, + 160 + ], + "type": "text", + "content": "[47] Jaesik Park, Sudipta N Sinha, Yasuyuki Matsushita, Yu-Wing Tai, and In So Kweon. Robust multiview photometric stereo using planar mesh parameterization. IEEE transactions on pattern analysis and machine intelligence, 39(8):1591-1604, 2016." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 162, + 545, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 162, + 545, + 205 + ], + "spans": [ + { + "bbox": [ + 307, + 162, + 545, + 205 + ], + "type": "text", + "content": "[48] Nikhila Ravi, Jeremy Reizenstein, David Novotny, Taylor Gordon, Wan-Yen Lo, Justin Johnson, and Georgia Gkioxari. Accelerating 3d deep learning with pytorch3d. arXiv:2007.08501, 2020." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 206, + 545, + 248 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 206, + 545, + 248 + ], + "spans": [ + { + "bbox": [ + 307, + 206, + 545, + 248 + ], + "type": "text", + "content": "[49] Johannes L Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4104-4113, 2016." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 250, + 545, + 316 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 250, + 545, + 316 + ], + "spans": [ + { + "bbox": [ + 307, + 250, + 545, + 316 + ], + "type": "text", + "content": "[50] Johannes L Schonberger, Enliang Zheng, Jan-Michael Frahm, and Marc Pollefeys. Pixelwise view selection for unstructured multi-view stereo. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part III 14, pages 501-518. Springer, 2016." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 316, + 545, + 370 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 316, + 545, + 370 + ], + "spans": [ + { + "bbox": [ + 307, + 316, + 545, + 370 + ], + "type": "text", + "content": "[51] Soumyadip Sengupta, Angjoo Kanazawa, Carlos D Castillo, and David W Jacobs. Sfsnet: Learning shape, reflectance and illuminance of facesin the wild'. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 6296-6305, 2018." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 372, + 545, + 425 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 372, + 545, + 425 + ], + "spans": [ + { + "bbox": [ + 307, + 372, + 545, + 425 + ], + "type": "text", + "content": "[52] Boxin Shi, Zhe Wu Mo, Dinglong Duan, Sai-Kit Yeung, and Ping Tan. A benchmark dataset and evaluation for non-lambertian and uncalibrated photometric stereo. IEEE Trans. on Pattern Analysis and Machine Intelligence (TPAMI), 41(2):271-284, 2019." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 426, + 545, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 426, + 545, + 491 + ], + "spans": [ + { + "bbox": [ + 307, + 426, + 545, + 491 + ], + "type": "text", + "content": "[53] Pratul P Srinivasan, Boyang Deng, Xiuming Zhang, Matthew Tancik, Ben Mildenhall, and Jonathan T Barron. Nerv: Neural reflectance and visibility fields for relighting and view synthesis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7495-7504, 2021." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 493, + 545, + 547 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 493, + 545, + 547 + ], + "spans": [ + { + "bbox": [ + 307, + 493, + 545, + 547 + ], + "type": "text", + "content": "[54] Christoph Strecha, Rik Fransens, and Luc Van Gool. Wide-baseline stereo from multiple views: a probabilistic account. In Proceedings of the 2004 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 2004. CVPR 2004., volume 1, pages I-I. IEEE, 2004." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 548, + 545, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 548, + 545, + 602 + ], + "spans": [ + { + "bbox": [ + 307, + 548, + 545, + 602 + ], + "type": "text", + "content": "[55] Christoph Strecha, Rik Fransens, and Luc Van Gool. Combined depth and outlier estimation in multi-view stereo. In 2006 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'06), volume 2, pages 2394-2401. IEEE, 2006." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 603, + 545, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 603, + 545, + 635 + ], + "spans": [ + { + "bbox": [ + 307, + 603, + 545, + 635 + ], + "type": "text", + "content": "[56] Jiaming Sun, Yiming Xie, Linghao Chen, Xiaowei Zhou, and Hujun Bao. NeuralRecon: Real-time coherent 3D reconstruction from monocular video. CVPR, 2021." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 636, + 545, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 636, + 545, + 679 + ], + "spans": [ + { + "bbox": [ + 307, + 636, + 545, + 679 + ], + "type": "text", + "content": "[57] Olivia Wiles and Andrew Zisserman. Silnet: Single- and multi-view reconstruction by learning from silhouettes. In British Machine Vision Conference 2017, BMVC 2017, London, UK, September 4-7, 2017. BMVA Press, 2017." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "type": "text", + "content": "[58] Robert J Woodham. Photometric method for determining surface orientation from multiple images. Optical engineering, 19(1):139-144, 1980." + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "12535" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 542 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[59] Qingshan Xu and Wenbing Tao. Learning inverse depth regression for multi-view stereo with correlation cost volume. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 12508-12515, 2020." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 118, + 286, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 118, + 286, + 161 + ], + "spans": [ + { + "bbox": [ + 49, + 118, + 286, + 161 + ], + "type": "text", + "content": "[60] Zexiang Xu, Kalyan Sunkavalli, Sunil Hadap, and Ravi Ramamoorthi. Deep image-based relighting from optimal sparse samples. ACM Transactions on Graphics (TOG), 37(4):126, 2018." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 163, + 286, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 163, + 286, + 205 + ], + "spans": [ + { + "bbox": [ + 49, + 163, + 286, + 205 + ], + "type": "text", + "content": "[61] Wenqi Yang, Guanying Chen, Chaofeng Chen, Zhenfang Chen, and Kwan-Yee K Wong. Ps-nerf: Neural inverse rendering for multi-view photometric stereo. arXiv preprint arXiv:2207.11406, 2022." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 208, + 286, + 251 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 208, + 286, + 251 + ], + "spans": [ + { + "bbox": [ + 49, + 208, + 286, + 251 + ], + "type": "text", + "content": "[62] Yao Yao, Zixin Luo, Shiwei Li, Tian Fang, and Long Quan. Mvsnet: Depth inference for unstructured multi-view stereo. In Proceedings of the European conference on computer vision (ECCV), pages 767-783, 2018." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 253, + 286, + 296 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 253, + 286, + 296 + ], + "spans": [ + { + "bbox": [ + 49, + 253, + 286, + 296 + ], + "type": "text", + "content": "[63] Yao Yao, Zixin Luo, Shiwei Li, Tianwei Shen, Tian Fang, and Long Quan. Recurrent mvvsnet for high-resolution multiview stereo depth inference. Computer Vision and Pattern Recognition (CVPR), 2019." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 297, + 286, + 351 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 297, + 286, + 351 + ], + "spans": [ + { + "bbox": [ + 49, + 297, + 286, + 351 + ], + "type": "text", + "content": "[64] Lior Yariv, Yoni Kasten, Dror Moran, Meirav Galun, Matan Atzmon, Basri Ronen, and Yaron Lipman. Multiview neural surface reconstruction by disentangling geometry and appearance. Advances in Neural Information Processing Systems, 33:2492-2502, 2020." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 353, + 286, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 353, + 286, + 407 + ], + "spans": [ + { + "bbox": [ + 49, + 353, + 286, + 407 + ], + "type": "text", + "content": "[65] Kai Zhang, Fujun Luan, Qianqian Wang, Kavita Bala, and Noah Snavely. Physg: Inverse rendering with spherical gaussians for physics-based material editing and relighting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5453-5462, 2021." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 409, + 286, + 463 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 409, + 286, + 463 + ], + "spans": [ + { + "bbox": [ + 49, + 409, + 286, + 463 + ], + "type": "text", + "content": "[66] Xiuming Zhang, Pratul P Srinivasan, Boyang Deng, Paul Debevec, William T Freeman, and Jonathan T Barron. Nerfactor: Neural factorization of shape and reflectance under an unknown illumination. ACM Transactions on Graphics (TOG), 40(6):1-18, 2021." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 464, + 286, + 497 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 464, + 286, + 497 + ], + "spans": [ + { + "bbox": [ + 49, + 464, + 286, + 497 + ], + "type": "text", + "content": "[67] Zhengyou Zhang. Iterative point matching for registration of free-form curves and surfaces. International journal of computer vision, 13(2):119-152, 1994." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 498, + 286, + 542 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 498, + 286, + 542 + ], + "spans": [ + { + "bbox": [ + 49, + 498, + 286, + 542 + ], + "type": "text", + "content": "[68] Zhenglong Zhou, Zhe Wu, and Ping Tan. Multi-view photometric stereo with spatially varying isotropic materials. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1482-1489, 2013." + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "12536" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 11 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/40801689-afc7-4c4a-b4e3-8cbca2d70a56_content_list.json b/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/40801689-afc7-4c4a-b4e3-8cbca2d70a56_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..e2007bfb5155374415be7bfa6e5674c9e6c19fe8 --- /dev/null +++ b/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/40801689-afc7-4c4a-b4e3-8cbca2d70a56_content_list.json @@ -0,0 +1,1735 @@ +[ + { + "type": "text", + "text": "MagicFusion: Boosting Text-to-Image Generation Performance by Fusing Diffusion Models", + "text_level": 1, + "bbox": [ + 166, + 130, + 805, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Jing Zhao $^{1*}$ , Heliang Zheng $^{2}$ , Chaoyue Wang $^{2}$ , Long Lan $^{1}$ , Wenjing Yang $^{1\\dagger}$", + "bbox": [ + 189, + 209, + 785, + 229 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{1}$ National University of Defense Technology, Changsha, China,", + "bbox": [ + 240, + 229, + 738, + 248 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{2}$ JD Explore Academy, Beijing, China", + "bbox": [ + 336, + 247, + 640, + 265 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{zhaojing,long.lan,wenjing.yang}@nudt.edu.cn,zhenghllj@gmail.com,chaoyue.wang@outlook.com", + "bbox": [ + 86, + 267, + 890, + 282 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/c53a296ef2f0ac2479375b6f989d973ad745e0409f3bdd1aa7efe795781ff089.jpg", + "image_caption": [ + "Figure 1: \"MagicFusion\". Given two diffusion models, our method can preserve the strengths of each individual model. (a) A general model [27] + a fine-grained car model to achieve fine-grained generation with complex scenes. (b) A general model + a DreamBooth model [28] to recontextualize specific objects with well-preserved details. (c) A general model + a cartoon model to generate creative scenes with photorealistic fidelity." + ], + "image_footnote": [], + "bbox": [ + 78, + 315, + 330, + 593 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/4015815acb025edfc67f3fa82bc8d01d1b7f9971da5177fda74d2f01126cc2fd.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 341, + 315, + 576, + 592 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/5e1ee9391e257e3bdb144457538a57f38401c9c775794644b5b98f50ab16a968.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 586, + 315, + 893, + 592 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 665, + 313, + 680 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The advent of open-source AI communities has produced a cornucopia of powerful text-guided diffusion models that are trained on various datasets. While few explorations have been conducted on ensembling such models to combine their strengths. In this work, we propose a simple yet effective method called Saliency-aware Noise Blending (SNB) that can empower the fused text-guided diffusion models to achieve more controllable generation. Specifically, we experimentally find that the responses of classifier-free guidance are highly related to the saliency of generated images. Thus we propose to trust different mod", + "bbox": [ + 73, + 696, + 470, + 863 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "els in their areas of expertise by blending the predicted noises of two diffusion models in a saliency-aware manner. SNB is training-free and can be completed within a DDIM sampling process. Additionally, it can automatically align the semantics of two noise spaces without requiring additional annotations such as masks. Extensive experiments show the impressive effectiveness of SNB in various applications. The project page is available at https://magicfusion.github.io/.", + "bbox": [ + 500, + 666, + 893, + 801 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 500, + 829, + 632, + 845 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In recent years, significant progress has been made in image generation [29, 6, 24, 23, 27, 20, 29, 5] thanks to breakthroughs in diffusion models [32, 29, 33] and large-", + "bbox": [ + 500, + 854, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Work done during an internship at JD Explore Academy.", + "bbox": [ + 94, + 875, + 401, + 887 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "† Corresponding authors.", + "bbox": [ + 96, + 887, + 225, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "22592", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "scale training [24, 20, 29, 5], as well as the contributions of open-source AI communities. Pre-trained large models have become an invaluable resource in this field. One of the most exciting developments has been text-guided diffusion models [24, 20, 29, 27]. A wide range of powerful text-guided diffusion models trained on various datasets has been publicly released. For example, general models (e.g., stable diffusion v1-4, v1-5, v2-1, etc. [27]) trained on large-scale multimodal datasets like LAION 5B [31], as well as more specialized models (e.g., Anything-v3) trained on cartoon and anime datasets or fine-grained categories such as cars [38]. There are even fine-tuned models designed for specific objects [28]. The vast amounts of data and computational cost have enabled these models to achieve impressive capabilities in various fields. However, few explorations have been conducted on ensembling such models to combine their strengths.", + "bbox": [ + 75, + 90, + 472, + 348 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Some works propose to add special symbols or signature phrases when fine-tuning models on new datasets [1]. This approach enables the model to generate novel image distributions while retaining its ability to generate from the original data distribution. However, there has been limited discussion on how to effectively combine the generation capabilities of these two distributions. One intuitive method for integrating the capabilities of two models involves taking a weighted average of their predicted noises [2]. However, such kind of fusions often fails to fully preserve the strengths of each model. Blended diffusion [3] proposes to spatially blend a noisy image and a predicted one, which has been explored in image editing tasks. However, this typically requires specifying a mask to edit particular objects, and few discussions have been conducted to blend the noises of two diffusion models.", + "bbox": [ + 75, + 351, + 472, + 592 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this work, we propose a simple yet effective method called Saliency-aware Noise Blending (SNB) that can empower the fused text-guided diffusion models to achieve more controllable generation. Specifically, we integrate two diffusion models by spatially blending the predicted noises. Our insight is to trust different models in their areas of expertise, thus the strengths of each individual model can be preserved. To obtain diffusion models' areas of expertise, we revisit the classifier-free guidance [13], which is widely adopted in text-guided diffusion models to enhance the difference between a given text and a null text in the predicted noise space. We experimentally find that the responses of classifier-free guidance are highly related to the saliency of generated images. To this end, we propose Saliency-aware Noise Blending that blends the predicted noises of two diffusion models based on their responses to classifier-free guidance.", + "bbox": [ + 75, + 595, + 472, + 852 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "SNB is training-free and can be completed within a DDIM sampling [33] process. Additionally, it can automatically align the semantics of two noise spaces without", + "bbox": [ + 76, + 854, + 470, + 902 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "requiring additional annotations such as masks. Our main contributions can be summarised as follows:", + "bbox": [ + 498, + 90, + 890, + 119 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose to fuse two well-trained diffusion models to achieve more powerful image generation, which is a novel and valuable topic.", + "- We propose a simple yet effective Saliency-aware Noise Blending method for text-guided diffusion models fusion, which can preserve the strengths of each individual model.", + "- We conduct extensive experiments on three challenging applications (i.e., a general model + a cartoon model, a fine-grained car model, and a Dream-Booth [28] model), and prove that SNB can significantly empower pre-trained diffusion models." + ], + "bbox": [ + 517, + 121, + 890, + 301 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The remainder of the paper is organized as follows. We describe related work in Section 2 and introduce our proposed SNB method in Section 3. An evaluation of three applications is presented in Section 4, followed by the results and comparisons with other methods in Section 5. Finally, a comprehensive summary of the paper is presented and an analysis of the limitations is provided in Section 6.", + "bbox": [ + 496, + 303, + 890, + 409 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Works", + "text_level": 1, + "bbox": [ + 500, + 424, + 650, + 439 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Text-to-image synthesis", + "text_level": 1, + "bbox": [ + 500, + 450, + 717, + 465 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Text-guided image generation plays a significant role in image generation [43, 16, 7, 12, 36, 15, 17, 21, 22, 24, 42]. Previous works mainly focus on GAN-based [10] models and small-scale image-text datasets [45, 34, 37, 41, 40]. Since Transformer-based autoregressive models [8, 24] were proposed, more and more attention has been attracted to large-scale training. The emergence of denoising diffusion models is another milestone, which significantly boosts the generation fidelity [23, 30, 20, 27]. Notably, Stable Diffusion [27] is publicly released, enabling a large number of variants that are fine-tuned on different datasets. The vast amounts of data and computational cost have enabled these models to achieve impressive capabilities in various fields. However, few explorations have been conducted on assembling such models to combine their strengths.", + "bbox": [ + 496, + 473, + 890, + 700 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. Model Ensembling", + "text_level": 1, + "bbox": [ + 500, + 710, + 681, + 726 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Model ensembling is a powerful technique to distill the knowledge of multiple models and boost the performance, which is widely obtained in image understanding tasks, i.e., classification problems [44, 26, 11, 39], regression problems [19, 25] and clustering [35]. White such methods are hard to be adapted to generative models due to the large and complex image pixel space. Vision-aided GAN [14] proposes ensembling pre-trained vision models as a loss to guide the optimization of a generator. eDiff-I [4] proposes to ensemble different denoisers in different timesteps to improve the overall performance of image generation. In this", + "bbox": [ + 496, + 734, + 890, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "22593", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/4901b11e721ec37d70191db2a3f1e3d05d47a795f806d673ff60f866bb004624.jpg", + "image_caption": [ + "Figure 2: An overview of our Saliency-aware Noise Blending (SNB). Given two diffusion models, we first design a \"Noise to salience map\" module to obtain salience maps. After that, we can generate saliency-aware masks based on the salience maps. Finally, we blend the diffusion models in the noise space according to the mask. $(^{*})\\hat{\\epsilon}_{g}$ and $\\hat{\\epsilon}_e$ are noises instead of noisy images, and we add the image here just for visualization." + ], + "image_footnote": [], + "bbox": [ + 81, + 95, + 890, + 349 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "work, we propose to ensemble different pre-trained diffusion models in a novel dimension, i.e., spatial, which can be applied to various scenarios.", + "bbox": [ + 75, + 444, + 470, + 491 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Method", + "text_level": 1, + "bbox": [ + 76, + 503, + 171, + 518 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this section, we introduce our proposed saliency-aware noise blending. Specifically, we first review the widely obtained classifier-free guidance, after that, we revisit such guidance and experimentally find that the classifier-free guidance is secretly a saliency indicator. Based on the salience map, we can obtain a saliency-aware mask, which is further used to guide the blending of the noise of two diffusion models. Figure 2 show the whole pipeline, and more details can be found in the following.", + "bbox": [ + 75, + 527, + 468, + 666 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Preliminaries", + "text_level": 1, + "bbox": [ + 76, + 672, + 217, + 688 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Given a pre-trained text-guided diffusion model, we can generate images by a DDPM/DDIM sampling process, which progressively converts a Gaussian noise into an image for $T$ timesteps. Take the DDIM sampling for example, a denoising step can be denoted as:", + "bbox": [ + 75, + 696, + 468, + 773 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nx _ {t - 1} = \\sqrt {\\bar {\\alpha} _ {t - 1}} \\left(\\frac {x _ {t} - \\sqrt {1 - \\bar {\\alpha} _ {t}} \\hat {\\epsilon}}{\\sqrt {\\bar {\\alpha} _ {t}}}\\right) + \\sqrt {1 - \\bar {\\alpha} _ {t - 1}} \\hat {\\epsilon}, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 96, + 781, + 468, + 816 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $t$ indicates the timestep, $x$ is the noisy image, $\\bar{\\alpha}$ is related to a pre-defined variance schedule, and $\\hat{\\epsilon}$ is the predicted noise. The predicted noise can be re-modulated by classifier-free guidance [13], which is designed to extrapolate the output of the model in the direction of $\\epsilon_{\\theta}(x_t|c)$ and", + "bbox": [ + 75, + 824, + 470, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "away from $\\epsilon_{\\theta}(x_t|\\varnothing)$ as follows:", + "bbox": [ + 498, + 444, + 712, + 460 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {\\epsilon} = \\epsilon_ {\\theta} \\left(x _ {t} | \\varnothing\\right) + s \\cdot \\left(\\epsilon_ {\\theta} \\left(x _ {t} \\mid c\\right) - \\epsilon_ {\\theta} \\left(x _ {t} | \\varnothing\\right)\\right), \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 553, + 465, + 890, + 483 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\epsilon_{\\theta}$ is the pretrained model, $c$ is the text condition, $\\varnothing$ is a null text, $s$ is the guidance weight and increasing $s > 1$ strengthens the effect of guidance.", + "bbox": [ + 498, + 488, + 892, + 532 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Noise to Salience Map", + "text_level": 1, + "bbox": [ + 500, + 540, + 705, + 556 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We experimentally find that the classifier-free guidance introduced above is secretly a saliency indicator. Specifically, $\\epsilon_{\\theta}(x_t|c) - \\epsilon_{\\theta}(x_t|\\varnothing)$ in Eqn. 2 indicates the difference between a conditional prediction and an unconditional prediction, thus the objects and scenes appeared in the text condition would be emphasized with a large value, especially when we adopt a large guidance scale $s$ (e.g., 10-100). We visualize the re-modulated noises of Eqn. 2 and find that the important region does have high responses. To this end, we propose to obtain a salience map by the following operation:", + "bbox": [ + 496, + 564, + 890, + 717 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\Lambda \\left(\\epsilon_ {t}\\right) = \\operatorname {B l u r} \\left(\\operatorname {A b s} \\left(\\epsilon_ {\\theta} \\left(x _ {t} \\mid c\\right) - \\epsilon_ {\\theta} \\left(x _ {t} \\mid \\varnothing\\right)\\right)\\right) \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 553, + 729, + 890, + 746 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\Lambda (\\epsilon_t)$ represents the salience map, $Abs(\\cdot)$ calculates the absolute value of the input variables, and $Blur(\\cdot)$ is used to smooth the high-frequency noise, which can eliminate local interference responses and leverage the coherence of adjacent regions.", + "bbox": [ + 496, + 750, + 893, + 825 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.3. Saliency-aware Blending", + "text_level": 1, + "bbox": [ + 500, + 832, + 725, + 848 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The above discussions are all about a single diffusion model, and now let us move to the next stage, i.e., obtaining a blending mask based on two models' salience maps.", + "bbox": [ + 498, + 854, + 890, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "22594", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Given a general model and an expert model, we can obtain the corresponding salience maps by Eqn. 3, which are denoted as $\\Lambda^g$ and $\\Lambda^e$ , respectively. We first normalize these salience maps by the softmax function:", + "bbox": [ + 76, + 90, + 468, + 151 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\Lambda^ {g ^ {\\prime}} = \\operatorname {s o f t m a x} (k ^ {g} * \\Lambda^ {g}) \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 181, + 162, + 467, + 189 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\Lambda^ {e ^ {\\prime}} = \\operatorname {s o f t m a x} \\left(k ^ {e} * \\Lambda^ {e}\\right),\n$$\n", + "text_format": "latex", + "bbox": [ + 184, + 186, + 362, + 204 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $k^g$ and $k^e$ are hyper-parameters, i.e., temperature of the softmax. Note that the softmax here ensures the sum of each salience map to be a constant (i.e., 1), which means each model must focus on some regions instead of having a high response everywhere. When we integrate a general model and an expert model, the salience map of the general model tends to cover multiple objects to compose the whole scene, while the expert model tends to have a higher response to a specific object. Thus we obtain a blending mask $\\mathcal{M}$ by comparing these two salience maps:", + "bbox": [ + 76, + 215, + 470, + 367 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {M} = \\arg \\max \\left(\\Lambda^ {g ^ {\\prime}}, \\Lambda^ {e ^ {\\prime}}\\right) \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 189, + 378, + 468, + 398 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The saliency-aware mask is an effective guide to perform noise blending, which consists of binary values of 0 and 1, corresponding to the noise $\\epsilon_{g}$ and $\\epsilon_{e}$ respectively. We can obtain the fused noise as follows:", + "bbox": [ + 76, + 407, + 468, + 465 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {\\epsilon} = \\mathcal {M} \\odot \\hat {\\epsilon} _ {g} + (1 - \\mathcal {M}) \\odot \\hat {\\epsilon} _ {e}, \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 169, + 484, + 468, + 500 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\odot$ denotes Hadamard (element-wise) Product, and we omit $t$ for simplicity. In the specific implementation process, the fusion strategy is executed only when $t \\leq t_s$ , ensuring that the fusion results possess the fundamental structure of images generated by the general model. Algorithm 1 summarizes the process of the saliency-aware noise blending algorithm.", + "bbox": [ + 76, + 507, + 468, + 612 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Additional explanations on the three applications. In the three applications (i.e., a general model + a fine-grained model, a DreamBooth model, and a cartoon model) of this work, the expert model of the former two focuses on a specific object, while the last one contributes to the global structure of the generated image. In the last application, the cartoon model tends to focus on low-frequency structure and the general model focuses on high-frequency details. Thus the blended mask is not object-level, and we remove the blur operation in Eqn. 3 to facilitate such blending.", + "bbox": [ + 76, + 614, + 468, + 763 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Clarification of technique novelty. The overall process of this algorithm is quite simple, yet it is non-trivial by solving two challenges. Firstly, we leverage the classifier-free guidance to automatically identify each model's areas of expertise. The introduction of the hyper-parameter $k$ provides improved controllability for blending the two sources of images, thereby enabling greater creativity and flexibility in image generation based on SNB. Secondly, the task of obtaining saliency response values that are closely linked", + "bbox": [ + 76, + 763, + 468, + 900 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Algorithm 1 Saliency-aware Noise Blending", + "bbox": [ + 500, + 90, + 799, + 106 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Input: Two pre-trained models $\\epsilon_{\\theta_g}$ and $\\epsilon_{\\theta_e}$ , along with two prompts, $y_{g}$ and $y_{e}$ . gradient scale $s$ in Eq.(2). Hyperparameters $k^a$ and $k^b$ in Eq. (4) and fusion time $t_s$ .", + "bbox": [ + 500, + 109, + 890, + 155 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Output: The fused image $x_0$", + "bbox": [ + 500, + 156, + 697, + 170 + ], + "page_idx": 3 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1: $x_{T}\\sim \\mathcal{N}(0,I)$", + "2: for $t$ from $T$ to 0 do", + "3: if $t > t_{s}$ then", + "4: $\\epsilon_{t} = \\epsilon_{t_{g}}$", + "5: else", + "6: $\\epsilon_{t_q} = \\epsilon_{\\theta_q}(x_t|c_g),\\epsilon_{t_e} = \\epsilon_{\\theta_e}(x_t|c_e)$", + "7: get $\\Lambda^g (\\epsilon_{t_g})$ and $\\Lambda^{e}(\\epsilon_{t_{e}})$ according to Eq.(3).", + "8: get $\\Lambda^{g'}(\\epsilon_{t_g})$ and $\\Lambda^{e'}(\\epsilon_{t_e})$ via Eq. (4).", + "9: $\\mathcal{M} = \\arg \\max (\\Lambda^{a'},\\Lambda^{b'})$", + "10: get the noise generated by classifier-free guidance $\\hat{\\epsilon}_{t_g}$ and $\\hat{\\epsilon}_{t_e}$ via Eq.(2).", + "11: $\\epsilon_{t} = \\mathcal{M}\\odot \\hat{\\epsilon}_{t_{g}} + (1 - \\mathcal{M})\\odot \\hat{\\epsilon}_{t_{e}}$", + "12: end if", + "13: $x_{t - 1}\\gets \\epsilon_t$ via Eq.(1)", + "14: end for", + "15: return $x_0$ ." + ], + "bbox": [ + 504, + 171, + 890, + 416 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "to prompt content is highly non-trivial. Secondly, in each sampling step, the two models take as input the blended $x_{t}$ , enabling automatic semantic alignment of the two models' noise space. We believe our exploration would contribute to the community and benefit the leveraging of pre-trained diffusion models.", + "bbox": [ + 496, + 446, + 890, + 537 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. Applications", + "text_level": 1, + "bbox": [ + 500, + 553, + 629, + 570 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In order to evaluate the effectiveness of our proposed method, we conduct experiments on three challenging applications. 1) Fine-grained Fusion, i.e., fusing a general and a fine-grained model to achieve fine-grained generation with complex scenes. 2) Recontextualization, i.e., fusing a general and a DreamBooth [28] model allows for the recontextualization of specific objects with well-preserved details. 3) Cross-domain Fusion, i.e., fusing a general and a cartoon model to combine the creative advantages of the cartoon model to generate complex scenes and the photorealistic fidelity of the general model. These experiments will allow us to evaluate the performance of our method across a range of scenarios and provide valuable insights into the strengths and limitations of our approach.", + "bbox": [ + 496, + 579, + 890, + 790 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Application 1: Fine-grained Fusion", + "text_level": 1, + "bbox": [ + 498, + 800, + 805, + 816 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The stable diffusion model [27] trained on large-scale multimodal datasets like LAION 5B [31] has shown impressive performance on general text-to-image synthesis. In our experiments, we use the publicly released stable diffusion v1-4. Meanwhile, fine-grained car models trained on (an", + "bbox": [ + 496, + 824, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "22595", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/937320c0d3cdb1c35ca2a49f8f451d29728488b2ea6e569a57a8c9642b862dd1.jpg", + "image_caption": [ + "Figure 3: Application 1: visualization results of Fine-grained Fusion. Our method enables fine-grained generation with complex scenes." + ], + "image_footnote": [], + "bbox": [ + 81, + 89, + 890, + 460 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "extension of) CompCars [38] can generate fine-grained car images with specific colors, viewpoints, types, brands, and models.", + "bbox": [ + 75, + 523, + 468, + 568 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "For instance, a scene description like \"a photo of a red car in a snowy forest\" can be fed into the general model, resulting in a corresponding image as shown in the first left column of Figure 3. Similarly, a specific car description like \"red hatchback Audi (imported) Audi A1 2010 e-tron\" can be fed into the car model, generating an Audi car that matches the prompt. To fuse the noise of the two models during the denoising sampling process, we propose the SNB method, which can produce a fused image of a red Audi hatchback car in a snowy forest. The fusion results of the general model and the fine-grained car model are illustrated in Figure 3, showing the ability to replace the car in the scene with a specific one while retaining the original scene unchanged. Notably, our SNB does not require additional annotations to specify the car's position in the original image, enabling automatic semantic alignment.", + "bbox": [ + 75, + 571, + 470, + 815 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Application 2: Recontextualization", + "text_level": 1, + "bbox": [ + 76, + 829, + 382, + 847 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Recontextualization, or named personalizing text-to-image generation, is proposed in previous works [9, 28], which aims to generate a creative scene for a specific ob", + "bbox": [ + 76, + 854, + 468, + 901 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "ject/concept. DreamBooth [28] proposes to fine-tune a diffusion model on several given images together with a placeholder word to enable the model to generate a specific object/concept. In this application, we integrate a general and a DreamBooth [28] model to allow for the recontextualization of specific objects with well-preserved details.", + "bbox": [ + 496, + 523, + 890, + 614 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Specifically, we first fine-tune the general model using multiple images of the target object. Thus the fine-tuned model can represent the specific object with the placeholder \"[ ]\" in the prompt. Next, we get through a sentence that describes a complex scene and \"a photo of a [ ] < class >\" into SNB to integrate the general model and the Dream-Booth model. Results can be found in Figure 4. It can be observed that our method can put a specific object with rich details into a complex scene.", + "bbox": [ + 496, + 616, + 892, + 753 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.3. Application 3: Cross-domain Fusion", + "text_level": 1, + "bbox": [ + 498, + 768, + 815, + 786 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Different models have distinct advantages when it comes to generating images with specific styles. For example, cartoon models are particularly skilled at creative composition and can generate scenes that are rarely observed in real-world scenarios. When we strive to generate images with unique and imaginative compositions, we can integrate a cartoon model to generate a distinctive scene and a general", + "bbox": [ + 496, + 794, + 890, + 902 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "22596", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/6d5663e63b0bb0ef7dce7909f563feb1179132e938474ae411e2b8de8d6738ef.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 83, + 89, + 197, + 191 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/3fe875f2c4c09105dfb6af345ec447f3e2f6fb7b54a526f1ced8f96496f8dcc5.jpg", + "image_caption": [ + "[ ] on a rock with snow mountain in the background." + ], + "image_footnote": [], + "bbox": [ + 207, + 90, + 429, + 189 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/4a13bb59ebb65187504b8c7a648e8172e9fe90be8e909bb89ed50696eeb80ce5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 437, + 90, + 658, + 188 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/45b7ac88bda42a346c6adec4f1179715b1976a88e4a5ddfa3fc7a4afa5dff9d4.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 666, + 90, + 887, + 188 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/c71c22d7f9458505e133dfb564f0c5cf05987c3f6fad3e94a7e064f9af3873b2.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 83, + 199, + 196, + 299 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/6801c958173bf18ccf56787924811b40b3d72c0cd2cc27cd0d45048ef1d1a539.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 209, + 213, + 429, + 299 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/d407e9c57a1a1c9095c780b0804526436a5ceee96559329458cca4f8efbb06ee.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 437, + 199, + 658, + 299 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/deb8230afd6a20a9f1ad36dada99a65bd123866ccaba6b615427a2a3e2c19138.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 666, + 199, + 887, + 299 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/71df950b17e0627e13ff035d8262d89f858a78b290bec10ef0ceda65ddac58e0.jpg", + "image_caption": [ + "Figure 4: Application 2: visualization results of Recontextualization. Our method can recontextualize specific objects in complex scenes with well-preserved details." + ], + "image_footnote": [], + "bbox": [ + 83, + 311, + 199, + 409 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/d8b30b64a3a857632cc673cb51f7427ffa2012c80958ecf25cd94d4525d4fc71.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 209, + 309, + 429, + 407 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/548757c867aaadd4b4b46ab6481f07a745e855ddd38473cdbd288106aaeeacc3.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 437, + 309, + 658, + 407 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/868be75c33ed82c789b69b490e3012336ada6357c27e4796dd39d0a837e9975c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 666, + 309, + 885, + 407 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/956420edf4cd12814549833214ed1303273b823ddcb130ac5c3a91f9cebe68a9.jpg", + "image_caption": [ + "Figure 5: Application 3: visualization results of Cross-domain Fusion. Our method can combine the creative advantages of the cartoon model to generate complex scenes and the photorealistic fidelity of the general model." + ], + "image_footnote": [], + "bbox": [ + 84, + 460, + 890, + 645 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "model to make the content more realistic.", + "bbox": [ + 76, + 710, + 352, + 724 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this application, the same textual description of a scene is fed into both the general and the cartoon models. This allows us to generate two sets of noise that correspond to the same content but different styles during the sampling process. By fusing these two sets of noise, SNB generates images that exhibit both a creative composition and realistic content. As shown in Figure 5, our proposed SNB provides a powerful tool for achieving the balance of creative and realistic, and we believe that such a tool has the potential to benefit a wide range of applications in various fields, such as art and AI-aided design.", + "bbox": [ + 75, + 734, + 470, + 901 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Results and Comparisons", + "text_level": 1, + "bbox": [ + 500, + 709, + 738, + 727 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Compared to the General Model", + "text_level": 1, + "bbox": [ + 500, + 737, + 785, + 753 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The stable diffusion model is a widely used and versatile generative model in computer vision that can generate a diverse range of images based on prompts. However, when the prompts contain multiple content subjects, the general model's generation performance can become challenging, especially when the combination of these subjects is rare in real-world scenes. This limitation can result in missing subjects in the generated images, as observed in Application 1, where the general model fails to capture both the car and", + "bbox": [ + 496, + 763, + 893, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "22597", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/71060445afd3f71a4bf54c6bd4631a7adc56eb14aa6e71bd7e79b00f927803de.jpg", + "image_caption": [ + "Figure 6: Compared to the general model. The general model fails to precisely generate fine-grained objects and tends to miss some objects when the prompt is full of details." + ], + "image_footnote": [], + "bbox": [ + 83, + 92, + 890, + 272 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1ff4c252e02dde5cca65df01afa591d1d19ab5b6075f95fcc2bdffc1252de5b2.jpg", + "image_caption": [ + "Figure 7: Compared to DreamBooth [28]. Dreambooth struggles with preserving the details of the given objects, especially for complex and lengthy prompts." + ], + "image_footnote": [], + "bbox": [ + 81, + 323, + 890, + 506 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "the seagulls in the same scene. A similar issue is observed in Application 3 (Figure 1), where the general model cannot produce scenes that are uncommon in real-life, such as a lion wearing a crown (Figure 6). In addition, the general model has difficulty understanding the semantics of certain prompts, as observed in the case of \"a bee is making honey\" in Figure 5, where the model only combines the bee and honey in the same scene.", + "bbox": [ + 75, + 565, + 468, + 685 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "The proposed SNB can address these limitations, which integrates a specialized model, such as a model that focuses on cars in Application 1, or a cartoon model in Application 3, to improve the accuracy and realism of image generation. By leveraging the strengths of both the general and specialized models, our proposed approach can generate visually appealing and semantically rich images. This approach has the potential to advance the field of computer vision by enabling more sophisticated and realistic image generation.", + "bbox": [ + 75, + 686, + 468, + 823 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.2. Compared to Dreambooth", + "text_level": 1, + "bbox": [ + 76, + 832, + 316, + 848 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Dreambooth [28] presents an approach for synthesizing novel renditions of a given subject using a few images of the subject and the guidance of a text prompt, i.e., recon", + "bbox": [ + 75, + 854, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "textualization. However, it is challenging for Dreambooth to handle certain creative scene compositions, such as “a [] backpack on the moon.” Our empirical investigation reveals that Dreambooth struggles with integrating specific subjects into the scene, particularly in cases where the scenario is uncommon in reality. As illustrated in Figure 7, Dreambooth frequently produces images that either lack or exhibit inconsistencies in terms of specific subjects in such scenarios. In contrast, our approach excels at integrating a specific subject into the scene while maintaining fidelity to the prompt. Although Dreambooth can generate contextually relevant images for brief prompts like “a [] bag on a garden bench,” it may not accurately capture the finer details of the subject, such as the graphic texture of the bag. In contrast, our approach not only generates images that adhere to the prompt but also reproduces subject details with greater accuracy.", + "bbox": [ + 496, + 565, + 890, + 821 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.3. Compared to Annotated Masks", + "text_level": 1, + "bbox": [ + 500, + 832, + 777, + 848 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Blended-Diffusion [3] firstly propose to blend the noisy image in each sampling step based on a given mask for image editing. Such a method can neither handle applica", + "bbox": [ + 496, + 854, + 892, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "22598", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/ead9e6c9fb6b83d2cd1eee80a6c546e77a66ba3a7fb4c1b600e0984aad70b902.jpg", + "image_caption": [ + "Figure 8: Compared to annotated masks. Our saliency-aware mask achieves better composing performance, e.g., generating snow on the car." + ], + "image_footnote": [], + "bbox": [ + 81, + 88, + 467, + 279 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/167a05b5a8a58f35dcc27a0fef827436dbd354ea44169497c68330caa77a02a4.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 490, + 88, + 890, + 277 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/f0a07eba5f8255da381de24fb4ea593582c56421c753f472ef8e471d5bd363fe.jpg", + "image_caption": [ + "Cross-domain Fusion: A bee is making honey" + ], + "image_footnote": [], + "bbox": [ + 81, + 325, + 467, + 531 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/b7c16dcb7dc76be9b258e11c5e7e462f5d89e23ad68ac22dc40e05f4c46b52cf.jpg", + "image_caption": [ + "Recontextualization: [ ] on the sofa in the living room, decorated with green plants and sunny", + "Figure 9: Compared to weighted sum. Directly averaging the two noises cannot well preserve each model's strengths and leads to cluttered image content." + ], + "image_footnote": [], + "bbox": [ + 498, + 327, + 890, + 532 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "tions like cross-domain fusion nor perform well on a mixed object and scene content, such as \"a car in a snowy forest.\" As depicted in Figure 8, a comparison between our method and a mask-based approach demonstrates that our SNB method accurately preserves detailed subject features influenced by the scene, like the snow on the car's hood and wheels. In contrast, the mask-based method replaces the entire car area, resulting in a loss of subject details within the scene. Overall, our SNB yields more natural and realistic results when editing or replacing scene content, particularly in scenarios with mixed object and scene content.", + "bbox": [ + 75, + 628, + 472, + 795 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4. Compared to Weighted Sum", + "text_level": 1, + "bbox": [ + 76, + 813, + 331, + 830 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "The success of SNB hinges upon its ability to create a high-quality mask based on the noise generated by the two models, which is then used to determine content coverage and retention. As shown in Figure 9, the experimental re", + "bbox": [ + 75, + 839, + 470, + 902 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "sults of SNB and the fusion method that directly averages the two noises differ significantly. When the weighted sum of two noises is used, the resulting image content appears cluttered and lacks the desired semantic alignment. In contrast, our SNB method outperforms the direct averaging method by achieving precise semantic alignment, resulting in more accurate and realistic image content.", + "bbox": [ + 496, + 628, + 892, + 737 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "It is worth noting that, CDM [18] is belong to the case of weighted sum, which treats two noises equally in different regions, while we trust different models in different regions by designing a saliency-aware fusion mechanism. We further show the comparison results with CDM in Fig. 10. CDM fails to generate accurate car images in the case of complex prompts (left) and tends to produce conceptually mixed images or exhibits unstable performance (right). In contrast, our proposed method can accurately generate specified images of cars as well as vivid depictions", + "bbox": [ + 496, + 750, + 893, + 902 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "22599", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/5300f61b98b2de7dcef81ecc4a3c08aecb1aeffb169b99faff5671702cc92ae3.jpg", + "image_caption": [ + "Figure 10: Comparisons with CDM. In the case of complex prompts (left), CDM fails to generate accurate car images. Moreover, CDM tends to produce conceptually mixed images (mid) or exhibits unstable performance (right)." + ], + "image_footnote": [], + "bbox": [ + 80, + 87, + 467, + 253 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/d3a684bef9f0796a0e62c29eb5a87e88f04cf1cc6cf8f3c109b527f7ef35456c.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Text-Image SimilarityImage Similarity
App. 1 ↑App. 3 ↑App. 2 ↑
Ours31.1832.760.8401
Baseline29.5631.010.7582
", + "bbox": [ + 84, + 332, + 460, + 400 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/48eebedbcc82f8b4aa5357607260d712c44d5effc86d85b3d26123412d2e0d4c.jpg", + "table_caption": [ + "Table 1: The CLIP-based Quantitative Metrics." + ], + "table_footnote": [], + "table_body": "
App. 1App. 2App. 3
Ours better81.4%84.7%79.3%
", + "bbox": [ + 96, + 433, + 450, + 469 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 2: Human evaluations.", + "bbox": [ + 176, + 472, + 367, + 484 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "of lions wearing crowns. Overall, our method demonstrates significantly better performance compared to CDM.", + "bbox": [ + 76, + 516, + 467, + 546 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5.5.Quantitative Metrics", + "text_level": 1, + "bbox": [ + 76, + 558, + 272, + 574 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We conducted quantitative evaluations for three corresponding applications. Specifically, we generated 5k test samples for each application to calculate the CLIP-based score. For application 1 and application 3, we measured the similarity between the generated images and the corresponding prompts in terms of Text-Image Similarity; for application 2, we calculated the similarity between the recontextualized images and the input images, which is referred to as Image Similarity. The evaluation results are presented in Table 1. Stable diffusion serves as the baseline for application 1 and application 3, while Dreambooth [28] serves as the baseline for application 2. Based on the results, it can be concluded that our method has demonstrated improved performance across all three applications.", + "bbox": [ + 75, + 582, + 468, + 792 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In addition, we also conducted 500 human evaluations for each application and presented the results in Table 2. In application 1 and application 3, we compare our model to stable diffusion, and in application 2, we compare it to Dreambooth. The data indicate that for all three applications, the majority of the participants regarded the images generated by our method as superior in quality.", + "bbox": [ + 75, + 795, + 468, + 901 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/0ed7c819e06ef13978e427a7e5b24dc22ee47eb4d3f04f2646edd9ab6f1cf61f.jpg", + "image_caption": [ + "Figure 11: Failure cases. Misalignments may appear due to the various car size." + ], + "image_footnote": [], + "bbox": [ + 501, + 87, + 890, + 282 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 343, + 617, + 359 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this work, we study the problem of integrating pretrained text-guided diffusion models to achieve more controllable generation. We propose a simple yet effective Saliency-aware Noise Blending (SNB) to preserve the strengths of each individual model. Extensive experiments on three challenging applications (i.e., a general model + a cartoon model, a fine-grained car model, and a Dream-Booth model) show that SNB can significantly empower pre-trained diffusion models. With the rapid development of pre-trained large generative models, we believe our work is of great value.", + "bbox": [ + 496, + 368, + 890, + 532 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Limitations. Although our method has demonstrated significant performance improvements, it may not be applicable in certain scenarios. The advantage of SNB is its ability to form automatic masks based on saliency response values; however, when the difference in object size between the two merged images is too large, semantic alignment can be difficult to achieve. As shown in Figure 11, when the general model produces cars that are either too large or too small, the results display misaligned semantic positions. In the future, we will keep on studying the integration of different large generative models and extend our method to more general settings.", + "bbox": [ + 496, + 534, + 890, + 715 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgments", + "text_level": 1, + "bbox": [ + 500, + 729, + 658, + 746 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work was partially supported by the National Natural Science Foundation of China: No. 91948303-1, 611803375, No. 61803375, No. 12002380, No. 62106278, No. 62101575, No. 61906210; the Postgraduate Scientific Research Innovation Project of Hunan Province: QL20210018 and the National Key R&D Program of China (2021ZD0140301).", + "bbox": [ + 496, + 753, + 890, + 859 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "22600", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Fine-tuned stable diffusion model trained on screenshots from a popular animation studio. https://huggingface.co/nitrosocke/mo-di-diffusion.2022.", + "[2] Merging two diffusion models. https://stable-diffusion-art.com/models/#merging_two_models. 2022.", + "[3] Omri Avrahami, Dani Lischinski, and Ohad Fried. Blended diffusion for text-driven editing of natural images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18208-18218, 2022.", + "[4] Yogesh Balaji, Seungjun Nah, Xun Huang, Arash Vahdat, Jiaming Song, Karsten Kreis, Miika Aittala, Timo Aila, Samuli Laine, Bryan Catanzaro, et al. eDIFF-I: Text-to-image diffusion models with an ensemble of expert denoisers. arXiv preprint arXiv:2211.01324, 2022.", + "[5] Huiwen Chang, Han Zhang, Jarred Barber, AJ Maschinot, Jose Lezama, Lu Jiang, Ming-Hsuan Yang, Kevin Murphy, William T Freeman, Michael Rubinstein, et al. Muse: Text-to-image generation via masked generative transformers. arXiv preprint arXiv:2301.00704, 2023.", + "[6] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Advances in Neural Information Processing Systems, 34:8780-8794, 2021.", + "[7] Ming Ding, Zhuoyi Yang, Wenyi Hong, Wendi Zheng, Chang Zhou, Da Yin, Junyang Lin, Xu Zou, Zhou Shao, Hongxia Yang, et al. Cogview: Mastering text-to-image generation via transformers. Advances in Neural Information Processing Systems, 34:19822-19835, 2021.", + "[8] Patrick Esser, Robin Rombach, and Bjorn Ommer. Taming transformers for high-resolution image synthesis. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 12873-12883, 2021.", + "[9] Rinon Gal, Yuval Alaluf, Yuval Atzmon, Or Patashnik, Amit H Bermano, Gal Chechik, and Daniel Cohen-Or. An image is worth one word: Personalizing text-to-image generation using textual inversion. arXiv preprint arXiv:2208.01618, 2022.", + "[10] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. Journal of Japan Society for Fuzzy Theory and Intelligent Informatics, 2014.", + "[11] D Gopika and B Azhagusundari. An analysis on ensemble methods in classification tasks. 2014.", + "[12] Tobias Hinz, Stefan Heinrich, and Stefan Wermter. Semantic object accuracy for generative text-to-image synthesis. IEEE transactions on pattern analysis and machine intelligence, 44(3):1552-1565, 2020.", + "[13] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. arXiv preprint arXiv:2207.12598, 2022.", + "[14] Nupur Kumari, Richard Zhang, Eli Shechtman, and Jun-Yan Zhu. Ensembling off-the-shelf models for gan training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10651-10662, 2022.", + "[15] Bowen Li, Xiaojuan Qi, Thomas Lukasiewicz, and Philip Torr. Controllable text-to-image generation. Advances in Neural Information Processing Systems, 32, 2019." + ], + "bbox": [ + 78, + 114, + 467, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[16] Gang Li, Heliang Zheng, Chaoyue Wang, Chang Li, Changwen Zheng, and Dacheng Tao. 3ddesigner: Towards photorealistic 3d object generation and editing with text-guided diffusion models. arXiv preprint arXiv:2211.14108, 2022.", + "[17] Wenbo Li, Pengchuan Zhang, Lei Zhang, Qiuyuan Huang, Xiaodong He, Siwei Lyu, and Jianfeng Gao. Object-driven text-to-image synthesis via adversarial training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12174-12182, 2019.", + "[18] Nan Liu, Shuang Li, Yilun Du, Antonio Torralba, and Joshua B. Tenenbaum. Compositional visual generation with composable diffusion models. In ECCV (17), volume 13677 of Lecture Notes in Computer Science, pages 423-439. Springer, 2022.", + "[19] Joao Mendes-Moreira, Carlos Soares, Alipio Mário Jorge, and Jorge Freire De Sousa. Ensemble approaches for regression: A survey. Acm computing surveys (csur), 45(1):1-40, 2012.", + "[20] Alex Nichol, Prafulla Dhariwal, Aditya Ramesh, Pranav Shyam, Pamela Mishkin, Bob McGrew, Ilya Sutskever, and Mark Chen. Glide: Towards photorealistic image generation and editing with text-guided diffusion models. arXiv preprint arXiv:2112.10741, 2021.", + "[21] Tingting Qiao, Jing Zhang, Duanqing Xu, and Dacheng Tao. Learn, imagine and create: Text-to-image generation from prior knowledge. Advances in neural information processing systems, 32, 2019.", + "[22] Tingting Qiao, Jing Zhang, Duanqing Xu, and Dacheng Tao. Mirrorgan: Learning text-to-image generation by redescription. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1505-1514, 2019.", + "[23] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022.", + "[24] Aditya Ramesh, Mikhail Pavlov, Gabriel Goh, Scott Gray, Chelsea Voss, Alec Radford, Mark Chen, and Ilya Sutskever. Zero-shot text-to-image generation. In International Conference on Machine Learning, pages 8821-8831. PMLR, 2021.", + "[25] Ye Ren, PN Suganthan, and N Srikanth. Ensemble methods for wind and solar power forecasting—a state-of-the-art review. Renewable and Sustainable Energy Reviews, 50:82-91, 2015.", + "[26] Lior Rokach. Ensemble-based classifiers. Artificial intelligence review, 33:1-39, 2010.", + "[27] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684-10695, 2022.", + "[28] Nataniel Ruiz, Yuanzhen Li, Varun Jampani, Yael Pritch, Michael Rubinstein, and Kfir Aberman. Dreambooth: Fine tuning text-to-image diffusion models for subject-driven generation. arXiv preprint arXiv:2208.12242, 2022.", + "[29] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed" + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "22601", + "bbox": [ + 478, + 945, + 517, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022.", + "[30] Chitwan Saharia, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022.", + "[31] Christoph Schuhmann, Romain Beaumont, Richard Vencu, Cade Gordon, Ross Wightman, Mehdi Cherti, Theo Coombes, Aarush Katta, Clayton Mullis, Mitchell Wortsman, et al. Laion-5b: An open large-scale dataset for training next generation image-text models. arXiv preprint arXiv:2210.08402, 2022.", + "[32] Jascha Sohl-Dickstein, Eric Weiss, Niru Maheswaranathan, and Surya Ganguli. Deep unsupervised learning using nonequilibrium thermodynamics. In International Conference on Machine Learning, pages 2256-2265. PMLR, 2015.", + "[33] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. arXiv preprint arXiv:2010.02502, 2020.", + "[34] Ming Tao, Hao Tang, Songsong Wu, Nicu Sebe, Xiao-Yuan Jing, Fei Wu, and Bingkun Bao. Df-gan: Deep fusion generative adversarial networks for text-to-image synthesis. arXiv preprint arXiv:2008.05865, 2020.", + "[35] Sandro Vega-Pons and José Ruiz-Shulcloper. A survey of clustering ensemble algorithms. International Journal of Pattern Recognition and Artificial Intelligence, 25(03):337-372, 2011.", + "[36] Huikai Wu, Shuai Zheng, Junge Zhang, and Kaiqi Huang. Gp-gan: Towards realistic high-resolution image blending. In Proceedings of the 27th ACM international conference on multimedia, pages 2487-2495, 2019.", + "[37] Tao Xu, Pengchuan Zhang, Qiuyuan Huang, Han Zhang, Zhe Gan, Xiaolei Huang, and Xiaodong He. Attngan: Fine-grained text to image generation with attentional generative adversarial networks. Cornell University - arXiv, 2017.", + "[38] Linjie Yang, Ping Luo, Chen Change Loy, and Xiaou Tang. A large-scale car dataset for fine-grained categorization and verification. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3973-3981, 2015.", + "[39] Pengyi Yang, Yee Hwa Yang, Bing B Zhou, and Albert Y Zomaya. A review of ensemble methods in bioinformatics. Current Bioinformatics, 5(4):296-308, 2010.", + "[40] Hui Ye, Xiulong Yang, Martin Takac, Rajshekhar Sunderraman, and Shihao Ji. Improving text-to-image synthesis using contrastive learning. arXiv preprint arXiv:2107.02423, 2021.", + "[41] Han Zhang, Jing Yu Koh, Jason Baldridge, Honglak Lee, and Yinfei Yang. Cross-modal contrastive learning for text-to-image generation. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 833-842, 2021." + ], + "bbox": [ + 78, + 90, + 470, + 898 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[42] Zizhao Zhang, Yuanpu Xie, and Lin Yang. Photographic text-to-image synthesis with a hierarchically-nested adversarial network. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 6199-6208, 2018.", + "[43] Jing Zhao, Heliang Zheng, Chaoyue Wang, Long Lan, Wanrong Huang, and Wenjing Yang. Null-text guidance in diffusion models is secretly a cartoon-style creator. arXiv preprint arXiv:2305.06710, 2023.", + "[44] Ying Zhao, Jun Gao, and Xuezhi Yang. A survey of neural network ensembles. In 2005 international conference on neural networks and brain, volume 1, pages 438-442. IEEE, 2005.", + "[45] Minfeng Zhu, Pingbo Pan, Wei Chen, and Yi Yang. Dm-gan: Dynamic memory generative adversarial networks for text-to-image synthesis. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 5802-5810, 2019." + ], + "bbox": [ + 501, + 92, + 892, + 344 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "22602", + "bbox": [ + 478, + 945, + 519, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/40801689-afc7-4c4a-b4e3-8cbca2d70a56_model.json b/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/40801689-afc7-4c4a-b4e3-8cbca2d70a56_model.json new file mode 100644 index 0000000000000000000000000000000000000000..599226c6d84d216b4dc0ab55c6dabd206de6e36b --- /dev/null +++ b/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/40801689-afc7-4c4a-b4e3-8cbca2d70a56_model.json @@ -0,0 +1,2444 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.167, + 0.131, + 0.806, + 0.177 + ], + "angle": 0, + "content": "MagicFusion: Boosting Text-to-Image Generation Performance by Fusing Diffusion Models" + }, + { + "type": "text", + "bbox": [ + 0.19, + 0.21, + 0.786, + 0.231 + ], + "angle": 0, + "content": "Jing Zhao\\(^{1*}\\), Heliang Zheng\\(^{2}\\), Chaoyue Wang\\(^{2}\\), Long Lan\\(^{1}\\), Wenjing Yang\\(^{1\\dagger}\\)" + }, + { + "type": "text", + "bbox": [ + 0.241, + 0.23, + 0.739, + 0.249 + ], + "angle": 0, + "content": "\\(^{1}\\)National University of Defense Technology, Changsha, China," + }, + { + "type": "text", + "bbox": [ + 0.338, + 0.248, + 0.642, + 0.266 + ], + "angle": 0, + "content": "\\(^{2}\\)JD Explore Academy, Beijing, China" + }, + { + "type": "text", + "bbox": [ + 0.088, + 0.268, + 0.892, + 0.283 + ], + "angle": 0, + "content": "{zhaojing,long.lan,wenjing.yang}@nudt.edu.cn,zhenghllj@gmail.com,chaoyue.wang@outlook.com" + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.316, + 0.331, + 0.594 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.342, + 0.316, + 0.577, + 0.593 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.587, + 0.316, + 0.895, + 0.593 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.075, + 0.604, + 0.895, + 0.665 + ], + "angle": 0, + "content": "Figure 1: \"MagicFusion\". Given two diffusion models, our method can preserve the strengths of each individual model. (a) A general model [27] + a fine-grained car model to achieve fine-grained generation with complex scenes. (b) A general model + a DreamBooth model [28] to recontextualize specific objects with well-preserved details. (c) A general model + a cartoon model to generate creative scenes with photorealistic fidelity." + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.666, + 0.314, + 0.681 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.697, + 0.471, + 0.864 + ], + "angle": 0, + "content": "The advent of open-source AI communities has produced a cornucopia of powerful text-guided diffusion models that are trained on various datasets. While few explorations have been conducted on ensembling such models to combine their strengths. In this work, we propose a simple yet effective method called Saliency-aware Noise Blending (SNB) that can empower the fused text-guided diffusion models to achieve more controllable generation. Specifically, we experimentally find that the responses of classifier-free guidance are highly related to the saliency of generated images. Thus we propose to trust different mod" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.667, + 0.894, + 0.803 + ], + "angle": 0, + "content": "els in their areas of expertise by blending the predicted noises of two diffusion models in a saliency-aware manner. SNB is training-free and can be completed within a DDIM sampling process. Additionally, it can automatically align the semantics of two noise spaces without requiring additional annotations such as masks. Extensive experiments show the impressive effectiveness of SNB in various applications. The project page is available at https://magicfusion.github.io/." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.83, + 0.633, + 0.846 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.856, + 0.894, + 0.903 + ], + "angle": 0, + "content": "In recent years, significant progress has been made in image generation [29, 6, 24, 23, 27, 20, 29, 5] thanks to breakthroughs in diffusion models [32, 29, 33] and large-" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.875, + 0.402, + 0.888 + ], + "angle": 0, + "content": "*Work done during an internship at JD Explore Academy." + }, + { + "type": "page_footnote", + "bbox": [ + 0.098, + 0.888, + 0.227, + 0.9 + ], + "angle": 0, + "content": "† Corresponding authors." + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.875, + 0.402, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "22592" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.349 + ], + "angle": 0, + "content": "scale training [24, 20, 29, 5], as well as the contributions of open-source AI communities. Pre-trained large models have become an invaluable resource in this field. One of the most exciting developments has been text-guided diffusion models [24, 20, 29, 27]. A wide range of powerful text-guided diffusion models trained on various datasets has been publicly released. For example, general models (e.g., stable diffusion v1-4, v1-5, v2-1, etc. [27]) trained on large-scale multimodal datasets like LAION 5B [31], as well as more specialized models (e.g., Anything-v3) trained on cartoon and anime datasets or fine-grained categories such as cars [38]. There are even fine-tuned models designed for specific objects [28]. The vast amounts of data and computational cost have enabled these models to achieve impressive capabilities in various fields. However, few explorations have been conducted on ensembling such models to combine their strengths." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.352, + 0.473, + 0.593 + ], + "angle": 0, + "content": "Some works propose to add special symbols or signature phrases when fine-tuning models on new datasets [1]. This approach enables the model to generate novel image distributions while retaining its ability to generate from the original data distribution. However, there has been limited discussion on how to effectively combine the generation capabilities of these two distributions. One intuitive method for integrating the capabilities of two models involves taking a weighted average of their predicted noises [2]. However, such kind of fusions often fails to fully preserve the strengths of each model. Blended diffusion [3] proposes to spatially blend a noisy image and a predicted one, which has been explored in image editing tasks. However, this typically requires specifying a mask to edit particular objects, and few discussions have been conducted to blend the noises of two diffusion models." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.596, + 0.473, + 0.853 + ], + "angle": 0, + "content": "In this work, we propose a simple yet effective method called Saliency-aware Noise Blending (SNB) that can empower the fused text-guided diffusion models to achieve more controllable generation. Specifically, we integrate two diffusion models by spatially blending the predicted noises. Our insight is to trust different models in their areas of expertise, thus the strengths of each individual model can be preserved. To obtain diffusion models' areas of expertise, we revisit the classifier-free guidance [13], which is widely adopted in text-guided diffusion models to enhance the difference between a given text and a null text in the predicted noise space. We experimentally find that the responses of classifier-free guidance are highly related to the saliency of generated images. To this end, we propose Saliency-aware Noise Blending that blends the predicted noises of two diffusion models based on their responses to classifier-free guidance." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.472, + 0.903 + ], + "angle": 0, + "content": "SNB is training-free and can be completed within a DDIM sampling [33] process. Additionally, it can automatically align the semantics of two noise spaces without" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.121 + ], + "angle": 0, + "content": "requiring additional annotations such as masks. Our main contributions can be summarised as follows:" + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.122, + 0.892, + 0.167 + ], + "angle": 0, + "content": "- We propose to fuse two well-trained diffusion models to achieve more powerful image generation, which is a novel and valuable topic." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.168, + 0.892, + 0.227 + ], + "angle": 0, + "content": "- We propose a simple yet effective Saliency-aware Noise Blending method for text-guided diffusion models fusion, which can preserve the strengths of each individual model." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.228, + 0.892, + 0.303 + ], + "angle": 0, + "content": "- We conduct extensive experiments on three challenging applications (i.e., a general model + a cartoon model, a fine-grained car model, and a Dream-Booth [28] model), and prove that SNB can significantly empower pre-trained diffusion models." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.122, + 0.892, + 0.303 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.304, + 0.892, + 0.41 + ], + "angle": 0, + "content": "The remainder of the paper is organized as follows. We describe related work in Section 2 and introduce our proposed SNB method in Section 3. An evaluation of three applications is presented in Section 4, followed by the results and comparisons with other methods in Section 5. Finally, a comprehensive summary of the paper is presented and an analysis of the limitations is provided in Section 6." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.425, + 0.651, + 0.44 + ], + "angle": 0, + "content": "2. Related Works" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.451, + 0.718, + 0.466 + ], + "angle": 0, + "content": "2.1. Text-to-image synthesis" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.474, + 0.892, + 0.701 + ], + "angle": 0, + "content": "Text-guided image generation plays a significant role in image generation [43, 16, 7, 12, 36, 15, 17, 21, 22, 24, 42]. Previous works mainly focus on GAN-based [10] models and small-scale image-text datasets [45, 34, 37, 41, 40]. Since Transformer-based autoregressive models [8, 24] were proposed, more and more attention has been attracted to large-scale training. The emergence of denoising diffusion models is another milestone, which significantly boosts the generation fidelity [23, 30, 20, 27]. Notably, Stable Diffusion [27] is publicly released, enabling a large number of variants that are fine-tuned on different datasets. The vast amounts of data and computational cost have enabled these models to achieve impressive capabilities in various fields. However, few explorations have been conducted on assembling such models to combine their strengths." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.711, + 0.682, + 0.727 + ], + "angle": 0, + "content": "2.2. Model Ensembling" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Model ensembling is a powerful technique to distill the knowledge of multiple models and boost the performance, which is widely obtained in image understanding tasks, i.e., classification problems [44, 26, 11, 39], regression problems [19, 25] and clustering [35]. White such methods are hard to be adapted to generative models due to the large and complex image pixel space. Vision-aided GAN [14] proposes ensembling pre-trained vision models as a loss to guide the optimization of a generator. eDiff-I [4] proposes to ensemble different denoisers in different timesteps to improve the overall performance of image generation. In this" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "22593" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.096, + 0.892, + 0.351 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.357, + 0.895, + 0.419 + ], + "angle": 0, + "content": "Figure 2: An overview of our Saliency-aware Noise Blending (SNB). Given two diffusion models, we first design a \"Noise to salience map\" module to obtain salience maps. After that, we can generate saliency-aware masks based on the salience maps. Finally, we blend the diffusion models in the noise space according to the mask. \\((^{*})\\hat{\\epsilon}_{g}\\) and \\(\\hat{\\epsilon}_e\\) are noises instead of noisy images, and we add the image here just for visualization." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.445, + 0.471, + 0.492 + ], + "angle": 0, + "content": "work, we propose to ensemble different pre-trained diffusion models in a novel dimension, i.e., spatial, which can be applied to various scenarios." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.504, + 0.172, + 0.519 + ], + "angle": 0, + "content": "3. Method" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.529, + 0.47, + 0.667 + ], + "angle": 0, + "content": "In this section, we introduce our proposed saliency-aware noise blending. Specifically, we first review the widely obtained classifier-free guidance, after that, we revisit such guidance and experimentally find that the classifier-free guidance is secretly a saliency indicator. Based on the salience map, we can obtain a saliency-aware mask, which is further used to guide the blending of the noise of two diffusion models. Figure 2 show the whole pipeline, and more details can be found in the following." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.674, + 0.218, + 0.689 + ], + "angle": 0, + "content": "3.1. Preliminaries" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.697, + 0.47, + 0.775 + ], + "angle": 0, + "content": "Given a pre-trained text-guided diffusion model, we can generate images by a DDPM/DDIM sampling process, which progressively converts a Gaussian noise into an image for \\( T \\) timesteps. Take the DDIM sampling for example, a denoising step can be denoted as:" + }, + { + "type": "equation", + "bbox": [ + 0.098, + 0.782, + 0.47, + 0.817 + ], + "angle": 0, + "content": "\\[\nx _ {t - 1} = \\sqrt {\\bar {\\alpha} _ {t - 1}} \\left(\\frac {x _ {t} - \\sqrt {1 - \\bar {\\alpha} _ {t}} \\hat {\\epsilon}}{\\sqrt {\\bar {\\alpha} _ {t}}}\\right) + \\sqrt {1 - \\bar {\\alpha} _ {t - 1}} \\hat {\\epsilon}, \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.471, + 0.903 + ], + "angle": 0, + "content": "where \\(t\\) indicates the timestep, \\(x\\) is the noisy image, \\(\\bar{\\alpha}\\) is related to a pre-defined variance schedule, and \\(\\hat{\\epsilon}\\) is the predicted noise. The predicted noise can be re-modulated by classifier-free guidance [13], which is designed to extrapolate the output of the model in the direction of \\(\\epsilon_{\\theta}(x_t|c)\\) and" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.445, + 0.714, + 0.461 + ], + "angle": 0, + "content": "away from \\(\\epsilon_{\\theta}(x_t|\\varnothing)\\) as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.555, + 0.466, + 0.892, + 0.484 + ], + "angle": 0, + "content": "\\[\n\\hat {\\epsilon} = \\epsilon_ {\\theta} \\left(x _ {t} | \\varnothing\\right) + s \\cdot \\left(\\epsilon_ {\\theta} \\left(x _ {t} \\mid c\\right) - \\epsilon_ {\\theta} \\left(x _ {t} | \\varnothing\\right)\\right), \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.489, + 0.893, + 0.534 + ], + "angle": 0, + "content": "where \\(\\epsilon_{\\theta}\\) is the pretrained model, \\(c\\) is the text condition, \\(\\varnothing\\) is a null text, \\(s\\) is the guidance weight and increasing \\(s > 1\\) strengthens the effect of guidance." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.541, + 0.707, + 0.558 + ], + "angle": 0, + "content": "3.2. Noise to Salience Map" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.565, + 0.892, + 0.718 + ], + "angle": 0, + "content": "We experimentally find that the classifier-free guidance introduced above is secretly a saliency indicator. Specifically, \\(\\epsilon_{\\theta}(x_t|c) - \\epsilon_{\\theta}(x_t|\\varnothing)\\) in Eqn. 2 indicates the difference between a conditional prediction and an unconditional prediction, thus the objects and scenes appeared in the text condition would be emphasized with a large value, especially when we adopt a large guidance scale \\(s\\) (e.g., 10-100). We visualize the re-modulated noises of Eqn. 2 and find that the important region does have high responses. To this end, we propose to obtain a salience map by the following operation:" + }, + { + "type": "equation", + "bbox": [ + 0.554, + 0.73, + 0.891, + 0.747 + ], + "angle": 0, + "content": "\\[\n\\Lambda \\left(\\epsilon_ {t}\\right) = \\operatorname {B l u r} \\left(\\operatorname {A b s} \\left(\\epsilon_ {\\theta} \\left(x _ {t} \\mid c\\right) - \\epsilon_ {\\theta} \\left(x _ {t} \\mid \\varnothing\\right)\\right)\\right) \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.894, + 0.826 + ], + "angle": 0, + "content": "where \\(\\Lambda (\\epsilon_t)\\) represents the salience map, \\(Abs(\\cdot)\\) calculates the absolute value of the input variables, and \\(Blur(\\cdot)\\) is used to smooth the high-frequency noise, which can eliminate local interference responses and leverage the coherence of adjacent regions." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.833, + 0.727, + 0.849 + ], + "angle": 0, + "content": "3.3. Saliency-aware Blending" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.902 + ], + "angle": 0, + "content": "The above discussions are all about a single diffusion model, and now let us move to the next stage, i.e., obtaining a blending mask based on two models' salience maps." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "22594" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.152 + ], + "angle": 0, + "content": "Given a general model and an expert model, we can obtain the corresponding salience maps by Eqn. 3, which are denoted as \\(\\Lambda^g\\) and \\(\\Lambda^e\\), respectively. We first normalize these salience maps by the softmax function:" + }, + { + "type": "equation", + "bbox": [ + 0.183, + 0.164, + 0.468, + 0.19 + ], + "angle": 0, + "content": "\\[\n\\Lambda^ {g ^ {\\prime}} = \\operatorname {s o f t m a x} (k ^ {g} * \\Lambda^ {g}) \\tag {4}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.185, + 0.187, + 0.364, + 0.205 + ], + "angle": 0, + "content": "\\[\n\\Lambda^ {e ^ {\\prime}} = \\operatorname {s o f t m a x} \\left(k ^ {e} * \\Lambda^ {e}\\right),\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.216, + 0.471, + 0.368 + ], + "angle": 0, + "content": "where \\( k^g \\) and \\( k^e \\) are hyper-parameters, i.e., temperature of the softmax. Note that the softmax here ensures the sum of each salience map to be a constant (i.e., 1), which means each model must focus on some regions instead of having a high response everywhere. When we integrate a general model and an expert model, the salience map of the general model tends to cover multiple objects to compose the whole scene, while the expert model tends to have a higher response to a specific object. Thus we obtain a blending mask \\( \\mathcal{M} \\) by comparing these two salience maps:" + }, + { + "type": "equation", + "bbox": [ + 0.19, + 0.38, + 0.469, + 0.4 + ], + "angle": 0, + "content": "\\[\n\\mathcal {M} = \\arg \\max \\left(\\Lambda^ {g ^ {\\prime}}, \\Lambda^ {e ^ {\\prime}}\\right) \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.408, + 0.469, + 0.467 + ], + "angle": 0, + "content": "The saliency-aware mask is an effective guide to perform noise blending, which consists of binary values of 0 and 1, corresponding to the noise \\(\\epsilon_{g}\\) and \\(\\epsilon_{e}\\) respectively. We can obtain the fused noise as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.17, + 0.485, + 0.469, + 0.501 + ], + "angle": 0, + "content": "\\[\n\\hat {\\epsilon} = \\mathcal {M} \\odot \\hat {\\epsilon} _ {g} + (1 - \\mathcal {M}) \\odot \\hat {\\epsilon} _ {e}, \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.508, + 0.469, + 0.613 + ], + "angle": 0, + "content": "where \\(\\odot\\) denotes Hadamard (element-wise) Product, and we omit \\(t\\) for simplicity. In the specific implementation process, the fusion strategy is executed only when \\(t \\leq t_s\\), ensuring that the fusion results possess the fundamental structure of images generated by the general model. Algorithm 1 summarizes the process of the saliency-aware noise blending algorithm." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.615, + 0.469, + 0.764 + ], + "angle": 0, + "content": "Additional explanations on the three applications. In the three applications (i.e., a general model + a fine-grained model, a DreamBooth model, and a cartoon model) of this work, the expert model of the former two focuses on a specific object, while the last one contributes to the global structure of the generated image. In the last application, the cartoon model tends to focus on low-frequency structure and the general model focuses on high-frequency details. Thus the blended mask is not object-level, and we remove the blur operation in Eqn. 3 to facilitate such blending." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.765, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Clarification of technique novelty. The overall process of this algorithm is quite simple, yet it is non-trivial by solving two challenges. Firstly, we leverage the classifier-free guidance to automatically identify each model's areas of expertise. The introduction of the hyper-parameter \\( k \\) provides improved controllability for blending the two sources of images, thereby enabling greater creativity and flexibility in image generation based on SNB. Secondly, the task of obtaining saliency response values that are closely linked" + }, + { + "type": "code_caption", + "bbox": [ + 0.501, + 0.092, + 0.8, + 0.107 + ], + "angle": 0, + "content": "Algorithm 1 Saliency-aware Noise Blending" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.11, + 0.892, + 0.156 + ], + "angle": 0, + "content": "Input: Two pre-trained models \\(\\epsilon_{\\theta_g}\\) and \\(\\epsilon_{\\theta_e}\\), along with two prompts, \\(y_{g}\\) and \\(y_{e}\\). gradient scale \\(s\\) in Eq.(2). Hyperparameters \\(k^a\\) and \\(k^b\\) in Eq. (4) and fusion time \\(t_s\\)." + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.157, + 0.698, + 0.171 + ], + "angle": 0, + "content": "Output: The fused image \\( x_0 \\)" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.172, + 0.626, + 0.186 + ], + "angle": 0, + "content": "1: \\(x_{T}\\sim \\mathcal{N}(0,I)\\)" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.187, + 0.67, + 0.2 + ], + "angle": 0, + "content": "2: for \\( t \\) from \\( T \\) to 0 do" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.202, + 0.64, + 0.216 + ], + "angle": 0, + "content": "3: if \\( t > t_{s} \\) then" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.219, + 0.617, + 0.233 + ], + "angle": 0, + "content": "4: \\(\\epsilon_{t} = \\epsilon_{t_{g}}\\)" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.234, + 0.576, + 0.244 + ], + "angle": 0, + "content": "5: else" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.246, + 0.784, + 0.262 + ], + "angle": 0, + "content": "6: \\(\\epsilon_{t_q} = \\epsilon_{\\theta_q}(x_t|c_g),\\epsilon_{t_e} = \\epsilon_{\\theta_e}(x_t|c_e)\\)" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.263, + 0.855, + 0.278 + ], + "angle": 0, + "content": "7: get \\(\\Lambda^g (\\epsilon_{t_g})\\) and \\(\\Lambda^{e}(\\epsilon_{t_{e}})\\) according to Eq.(3)." + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.279, + 0.808, + 0.296 + ], + "angle": 0, + "content": "8: get \\(\\Lambda^{g'}(\\epsilon_{t_g})\\) and \\(\\Lambda^{e'}(\\epsilon_{t_e})\\) via Eq. (4)." + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.297, + 0.727, + 0.312 + ], + "angle": 0, + "content": "9: \\(\\mathcal{M} = \\arg \\max (\\Lambda^{a'},\\Lambda^{b'})\\)" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.313, + 0.891, + 0.342 + ], + "angle": 0, + "content": "10: get the noise generated by classifier-free guidance \\(\\hat{\\epsilon}_{t_g}\\) and \\(\\hat{\\epsilon}_{t_e}\\) via Eq.(2)." + }, + { + "type": "text", + "bbox": [ + 0.506, + 0.343, + 0.775, + 0.358 + ], + "angle": 0, + "content": "11: \\(\\epsilon_{t} = \\mathcal{M}\\odot \\hat{\\epsilon}_{t_{g}} + (1 - \\mathcal{M})\\odot \\hat{\\epsilon}_{t_{e}}\\)" + }, + { + "type": "text", + "bbox": [ + 0.507, + 0.359, + 0.59, + 0.37 + ], + "angle": 0, + "content": "12: end if" + }, + { + "type": "text", + "bbox": [ + 0.507, + 0.373, + 0.688, + 0.387 + ], + "angle": 0, + "content": "13: \\(x_{t - 1}\\gets \\epsilon_t\\) via Eq.(1)" + }, + { + "type": "text", + "bbox": [ + 0.507, + 0.389, + 0.583, + 0.4 + ], + "angle": 0, + "content": "14: end for" + }, + { + "type": "text", + "bbox": [ + 0.507, + 0.404, + 0.606, + 0.417 + ], + "angle": 0, + "content": "15: return \\( x_0 \\)." + }, + { + "type": "list", + "bbox": [ + 0.506, + 0.172, + 0.891, + 0.417 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.448, + 0.892, + 0.538 + ], + "angle": 0, + "content": "to prompt content is highly non-trivial. Secondly, in each sampling step, the two models take as input the blended \\( x_{t} \\), enabling automatic semantic alignment of the two models' noise space. We believe our exploration would contribute to the community and benefit the leveraging of pre-trained diffusion models." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.554, + 0.63, + 0.571 + ], + "angle": 0, + "content": "4. Applications" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.58, + 0.892, + 0.791 + ], + "angle": 0, + "content": "In order to evaluate the effectiveness of our proposed method, we conduct experiments on three challenging applications. 1) Fine-grained Fusion, i.e., fusing a general and a fine-grained model to achieve fine-grained generation with complex scenes. 2) Recontextualization, i.e., fusing a general and a DreamBooth [28] model allows for the recontextualization of specific objects with well-preserved details. 3) Cross-domain Fusion, i.e., fusing a general and a cartoon model to combine the creative advantages of the cartoon model to generate complex scenes and the photorealistic fidelity of the general model. These experiments will allow us to evaluate the performance of our method across a range of scenarios and provide valuable insights into the strengths and limitations of our approach." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.801, + 0.807, + 0.818 + ], + "angle": 0, + "content": "4.1. Application 1: Fine-grained Fusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "The stable diffusion model [27] trained on large-scale multimodal datasets like LAION 5B [31] has shown impressive performance on general text-to-image synthesis. In our experiments, we use the publicly released stable diffusion v1-4. Meanwhile, fine-grained car models trained on (an" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "22595" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.09, + 0.891, + 0.462 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.467, + 0.893, + 0.498 + ], + "angle": 0, + "content": "Figure 3: Application 1: visualization results of Fine-grained Fusion. Our method enables fine-grained generation with complex scenes." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.524, + 0.47, + 0.569 + ], + "angle": 0, + "content": "extension of) CompCars [38] can generate fine-grained car images with specific colors, viewpoints, types, brands, and models." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.572, + 0.471, + 0.816 + ], + "angle": 0, + "content": "For instance, a scene description like \"a photo of a red car in a snowy forest\" can be fed into the general model, resulting in a corresponding image as shown in the first left column of Figure 3. Similarly, a specific car description like \"red hatchback Audi (imported) Audi A1 2010 e-tron\" can be fed into the car model, generating an Audi car that matches the prompt. To fuse the noise of the two models during the denoising sampling process, we propose the SNB method, which can produce a fused image of a red Audi hatchback car in a snowy forest. The fusion results of the general model and the fine-grained car model are illustrated in Figure 3, showing the ability to replace the car in the scene with a specific one while retaining the original scene unchanged. Notably, our SNB does not require additional annotations to specify the car's position in the original image, enabling automatic semantic alignment." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.83, + 0.383, + 0.848 + ], + "angle": 0, + "content": "4.2. Application 2: Recontextualization" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Recontextualization, or named personalizing text-to-image generation, is proposed in previous works [9, 28], which aims to generate a creative scene for a specific ob" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.524, + 0.892, + 0.616 + ], + "angle": 0, + "content": "ject/concept. DreamBooth [28] proposes to fine-tune a diffusion model on several given images together with a placeholder word to enable the model to generate a specific object/concept. In this application, we integrate a general and a DreamBooth [28] model to allow for the recontextualization of specific objects with well-preserved details." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.617, + 0.893, + 0.754 + ], + "angle": 0, + "content": "Specifically, we first fine-tune the general model using multiple images of the target object. Thus the fine-tuned model can represent the specific object with the placeholder \"[ ]\" in the prompt. Next, we get through a sentence that describes a complex scene and \"a photo of a [ ] < class >\" into SNB to integrate the general model and the Dream-Booth model. Results can be found in Figure 4. It can be observed that our method can put a specific object with rich details into a complex scene." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.77, + 0.816, + 0.787 + ], + "angle": 0, + "content": "4.3. Application 3: Cross-domain Fusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Different models have distinct advantages when it comes to generating images with specific styles. For example, cartoon models are particularly skilled at creative composition and can generate scenes that are rarely observed in real-world scenarios. When we strive to generate images with unique and imaginative compositions, we can integrate a cartoon model to generate a distinctive scene and a general" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "22596" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.09, + 0.198, + 0.192 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.209, + 0.091, + 0.431, + 0.19 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.439, + 0.091, + 0.66, + 0.189 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.668, + 0.091, + 0.888, + 0.189 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.084, + 0.2, + 0.197, + 0.3 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.21, + 0.2, + 0.433, + 0.21 + ], + "angle": 0, + "content": "[ ] on a rock with snow mountain in the background." + }, + { + "type": "image", + "bbox": [ + 0.21, + 0.214, + 0.43, + 0.3 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.439, + 0.2, + 0.659, + 0.3 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.668, + 0.2, + 0.888, + 0.3 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.084, + 0.312, + 0.2, + 0.41 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.21, + 0.31, + 0.43, + 0.409 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.439, + 0.31, + 0.659, + 0.409 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.668, + 0.31, + 0.887, + 0.409 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.414, + 0.893, + 0.445 + ], + "angle": 0, + "content": "Figure 4: Application 2: visualization results of Recontextualization. Our method can recontextualize specific objects in complex scenes with well-preserved details." + }, + { + "type": "image", + "bbox": [ + 0.085, + 0.462, + 0.891, + 0.646 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.654, + 0.895, + 0.686 + ], + "angle": 0, + "content": "Figure 5: Application 3: visualization results of Cross-domain Fusion. Our method can combine the creative advantages of the cartoon model to generate complex scenes and the photorealistic fidelity of the general model." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.711, + 0.353, + 0.725 + ], + "angle": 0, + "content": "model to make the content more realistic." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.471, + 0.902 + ], + "angle": 0, + "content": "In this application, the same textual description of a scene is fed into both the general and the cartoon models. This allows us to generate two sets of noise that correspond to the same content but different styles during the sampling process. By fusing these two sets of noise, SNB generates images that exhibit both a creative composition and realistic content. As shown in Figure 5, our proposed SNB provides a powerful tool for achieving the balance of creative and realistic, and we believe that such a tool has the potential to benefit a wide range of applications in various fields, such as art and AI-aided design." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.71, + 0.74, + 0.728 + ], + "angle": 0, + "content": "5. Results and Comparisons" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.738, + 0.787, + 0.755 + ], + "angle": 0, + "content": "5.1. Compared to the General Model" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.894, + 0.903 + ], + "angle": 0, + "content": "The stable diffusion model is a widely used and versatile generative model in computer vision that can generate a diverse range of images based on prompts. However, when the prompts contain multiple content subjects, the general model's generation performance can become challenging, especially when the combination of these subjects is rare in real-world scenes. This limitation can result in missing subjects in the generated images, as observed in Application 1, where the general model fails to capture both the car and" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "22597" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.093, + 0.891, + 0.273 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.279, + 0.893, + 0.311 + ], + "angle": 0, + "content": "Figure 6: Compared to the general model. The general model fails to precisely generate fine-grained objects and tends to miss some objects when the prompt is full of details." + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.324, + 0.891, + 0.507 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.509, + 0.893, + 0.54 + ], + "angle": 0, + "content": "Figure 7: Compared to DreamBooth [28]. Dreambooth struggles with preserving the details of the given objects, especially for complex and lengthy prompts." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.566, + 0.47, + 0.686 + ], + "angle": 0, + "content": "the seagulls in the same scene. A similar issue is observed in Application 3 (Figure 1), where the general model cannot produce scenes that are uncommon in real-life, such as a lion wearing a crown (Figure 6). In addition, the general model has difficulty understanding the semantics of certain prompts, as observed in the case of \"a bee is making honey\" in Figure 5, where the model only combines the bee and honey in the same scene." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.687, + 0.47, + 0.824 + ], + "angle": 0, + "content": "The proposed SNB can address these limitations, which integrates a specialized model, such as a model that focuses on cars in Application 1, or a cartoon model in Application 3, to improve the accuracy and realism of image generation. By leveraging the strengths of both the general and specialized models, our proposed approach can generate visually appealing and semantically rich images. This approach has the potential to advance the field of computer vision by enabling more sophisticated and realistic image generation." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.833, + 0.317, + 0.849 + ], + "angle": 0, + "content": "5.2. Compared to Dreambooth" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Dreambooth [28] presents an approach for synthesizing novel renditions of a given subject using a few images of the subject and the guidance of a text prompt, i.e., recon" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.566, + 0.892, + 0.822 + ], + "angle": 0, + "content": "textualization. However, it is challenging for Dreambooth to handle certain creative scene compositions, such as “a [] backpack on the moon.” Our empirical investigation reveals that Dreambooth struggles with integrating specific subjects into the scene, particularly in cases where the scenario is uncommon in reality. As illustrated in Figure 7, Dreambooth frequently produces images that either lack or exhibit inconsistencies in terms of specific subjects in such scenarios. In contrast, our approach excels at integrating a specific subject into the scene while maintaining fidelity to the prompt. Although Dreambooth can generate contextually relevant images for brief prompts like “a [] bag on a garden bench,” it may not accurately capture the finer details of the subject, such as the graphic texture of the bag. In contrast, our approach not only generates images that adhere to the prompt but also reproduces subject details with greater accuracy." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.833, + 0.779, + 0.849 + ], + "angle": 0, + "content": "5.3. Compared to Annotated Masks" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.893, + 0.903 + ], + "angle": 0, + "content": "Blended-Diffusion [3] firstly propose to blend the noisy image in each sampling step based on a given mask for image editing. Such a method can neither handle applica" + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "22598" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.089, + 0.468, + 0.28 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.491, + 0.089, + 0.892, + 0.278 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.282, + 0.893, + 0.311 + ], + "angle": 0, + "content": "Figure 8: Compared to annotated masks. Our saliency-aware mask achieves better composing performance, e.g., generating snow on the car." + }, + { + "type": "image", + "bbox": [ + 0.083, + 0.327, + 0.468, + 0.532 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.144, + 0.54, + 0.43, + 0.555 + ], + "angle": 0, + "content": "Cross-domain Fusion: A bee is making honey" + }, + { + "type": "image", + "bbox": [ + 0.499, + 0.328, + 0.891, + 0.533 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.527, + 0.54, + 0.866, + 0.567 + ], + "angle": 0, + "content": "Recontextualization: [ ] on the sofa in the living room, decorated with green plants and sunny" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.573, + 0.893, + 0.604 + ], + "angle": 0, + "content": "Figure 9: Compared to weighted sum. Directly averaging the two noises cannot well preserve each model's strengths and leads to cluttered image content." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.63, + 0.473, + 0.796 + ], + "angle": 0, + "content": "tions like cross-domain fusion nor perform well on a mixed object and scene content, such as \"a car in a snowy forest.\" As depicted in Figure 8, a comparison between our method and a mask-based approach demonstrates that our SNB method accurately preserves detailed subject features influenced by the scene, like the snow on the car's hood and wheels. In contrast, the mask-based method replaces the entire car area, resulting in a loss of subject details within the scene. Overall, our SNB yields more natural and realistic results when editing or replacing scene content, particularly in scenarios with mixed object and scene content." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.814, + 0.332, + 0.831 + ], + "angle": 0, + "content": "5.4. Compared to Weighted Sum" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.471, + 0.903 + ], + "angle": 0, + "content": "The success of SNB hinges upon its ability to create a high-quality mask based on the noise generated by the two models, which is then used to determine content coverage and retention. As shown in Figure 9, the experimental re" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.63, + 0.893, + 0.738 + ], + "angle": 0, + "content": "sults of SNB and the fusion method that directly averages the two noises differ significantly. When the weighted sum of two noises is used, the resulting image content appears cluttered and lacks the desired semantic alignment. In contrast, our SNB method outperforms the direct averaging method by achieving precise semantic alignment, resulting in more accurate and realistic image content." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.895, + 0.903 + ], + "angle": 0, + "content": "It is worth noting that, CDM [18] is belong to the case of weighted sum, which treats two noises equally in different regions, while we trust different models in different regions by designing a saliency-aware fusion mechanism. We further show the comparison results with CDM in Fig. 10. CDM fails to generate accurate car images in the case of complex prompts (left) and tends to produce conceptually mixed images or exhibits unstable performance (right). In contrast, our proposed method can accurately generate specified images of cars as well as vivid depictions" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "22599" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.088, + 0.468, + 0.254 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.257, + 0.468, + 0.318 + ], + "angle": 0, + "content": "Figure 10: Comparisons with CDM. In the case of complex prompts (left), CDM fails to generate accurate car images. Moreover, CDM tends to produce conceptually mixed images (mid) or exhibits unstable performance (right)." + }, + { + "type": "table", + "bbox": [ + 0.086, + 0.333, + 0.462, + 0.401 + ], + "angle": 0, + "content": "
Text-Image SimilarityImage Similarity
App. 1 ↑App. 3 ↑App. 2 ↑
Ours31.1832.760.8401
Baseline29.5631.010.7582
" + }, + { + "type": "table_caption", + "bbox": [ + 0.117, + 0.403, + 0.428, + 0.417 + ], + "angle": 0, + "content": "Table 1: The CLIP-based Quantitative Metrics." + }, + { + "type": "table", + "bbox": [ + 0.097, + 0.434, + 0.451, + 0.47 + ], + "angle": 0, + "content": "
App. 1App. 2App. 3
Ours better81.4%84.7%79.3%
" + }, + { + "type": "table_caption", + "bbox": [ + 0.178, + 0.473, + 0.368, + 0.486 + ], + "angle": 0, + "content": "Table 2: Human evaluations." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.517, + 0.468, + 0.547 + ], + "angle": 0, + "content": "of lions wearing crowns. Overall, our method demonstrates significantly better performance compared to CDM." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.559, + 0.274, + 0.575 + ], + "angle": 0, + "content": "5.5.Quantitative Metrics" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.583, + 0.469, + 0.794 + ], + "angle": 0, + "content": "We conducted quantitative evaluations for three corresponding applications. Specifically, we generated 5k test samples for each application to calculate the CLIP-based score. For application 1 and application 3, we measured the similarity between the generated images and the corresponding prompts in terms of Text-Image Similarity; for application 2, we calculated the similarity between the recontextualized images and the input images, which is referred to as Image Similarity. The evaluation results are presented in Table 1. Stable diffusion serves as the baseline for application 1 and application 3, while Dreambooth [28] serves as the baseline for application 2. Based on the results, it can be concluded that our method has demonstrated improved performance across all three applications." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.796, + 0.469, + 0.902 + ], + "angle": 0, + "content": "In addition, we also conducted 500 human evaluations for each application and presented the results in Table 2. In application 1 and application 3, we compare our model to stable diffusion, and in application 2, we compare it to Dreambooth. The data indicate that for all three applications, the majority of the participants regarded the images generated by our method as superior in quality." + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.088, + 0.892, + 0.284 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.288, + 0.892, + 0.318 + ], + "angle": 0, + "content": "Figure 11: Failure cases. Misalignments may appear due to the various car size." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.344, + 0.619, + 0.36 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.369, + 0.892, + 0.534 + ], + "angle": 0, + "content": "In this work, we study the problem of integrating pretrained text-guided diffusion models to achieve more controllable generation. We propose a simple yet effective Saliency-aware Noise Blending (SNB) to preserve the strengths of each individual model. Extensive experiments on three challenging applications (i.e., a general model + a cartoon model, a fine-grained car model, and a Dream-Booth model) show that SNB can significantly empower pre-trained diffusion models. With the rapid development of pre-trained large generative models, we believe our work is of great value." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.535, + 0.892, + 0.717 + ], + "angle": 0, + "content": "Limitations. Although our method has demonstrated significant performance improvements, it may not be applicable in certain scenarios. The advantage of SNB is its ability to form automatic masks based on saliency response values; however, when the difference in object size between the two merged images is too large, semantic alignment can be difficult to achieve. As shown in Figure 11, when the general model produces cars that are either too large or too small, the results display misaligned semantic positions. In the future, we will keep on studying the integration of different large generative models and extend our method to more general settings." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.731, + 0.659, + 0.747 + ], + "angle": 0, + "content": "Acknowledgments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.755, + 0.892, + 0.861 + ], + "angle": 0, + "content": "This work was partially supported by the National Natural Science Foundation of China: No. 91948303-1, 611803375, No. 61803375, No. 12002380, No. 62106278, No. 62101575, No. 61906210; the Postgraduate Scientific Research Innovation Project of Hunan Province: QL20210018 and the National Key R&D Program of China (2021ZD0140301)." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "22600" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.115, + 0.468, + 0.156 + ], + "angle": 0, + "content": "[1] Fine-tuned stable diffusion model trained on screenshots from a popular animation studio. https://huggingface.co/nitrosocke/mo-di-diffusion.2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.157, + 0.468, + 0.185 + ], + "angle": 0, + "content": "[2] Merging two diffusion models. https://stable-diffusion-art.com/models/#merging_two_models. 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.187, + 0.468, + 0.241 + ], + "angle": 0, + "content": "[3] Omri Avrahami, Dani Lischinski, and Ohad Fried. Blended diffusion for text-driven editing of natural images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18208-18218, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.243, + 0.468, + 0.311 + ], + "angle": 0, + "content": "[4] Yogesh Balaji, Seungjun Nah, Xun Huang, Arash Vahdat, Jiaming Song, Karsten Kreis, Miika Aittala, Timo Aila, Samuli Laine, Bryan Catanzaro, et al. eDIFF-I: Text-to-image diffusion models with an ensemble of expert denoisers. arXiv preprint arXiv:2211.01324, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.312, + 0.468, + 0.381 + ], + "angle": 0, + "content": "[5] Huiwen Chang, Han Zhang, Jarred Barber, AJ Maschinot, Jose Lezama, Lu Jiang, Ming-Hsuan Yang, Kevin Murphy, William T Freeman, Michael Rubinstein, et al. Muse: Text-to-image generation via masked generative transformers. arXiv preprint arXiv:2301.00704, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.382, + 0.468, + 0.422 + ], + "angle": 0, + "content": "[6] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Advances in Neural Information Processing Systems, 34:8780-8794, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.424, + 0.468, + 0.493 + ], + "angle": 0, + "content": "[7] Ming Ding, Zhuoyi Yang, Wenyi Hong, Wendi Zheng, Chang Zhou, Da Yin, Junyang Lin, Xu Zou, Zhou Shao, Hongxia Yang, et al. Cogview: Mastering text-to-image generation via transformers. Advances in Neural Information Processing Systems, 34:19822-19835, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.494, + 0.468, + 0.549 + ], + "angle": 0, + "content": "[8] Patrick Esser, Robin Rombach, and Bjorn Ommer. Taming transformers for high-resolution image synthesis. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 12873-12883, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.55, + 0.468, + 0.618 + ], + "angle": 0, + "content": "[9] Rinon Gal, Yuval Alaluf, Yuval Atzmon, Or Patashnik, Amit H Bermano, Gal Chechik, and Daniel Cohen-Or. An image is worth one word: Personalizing text-to-image generation using textual inversion. arXiv preprint arXiv:2208.01618, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.62, + 0.468, + 0.688 + ], + "angle": 0, + "content": "[10] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. Journal of Japan Society for Fuzzy Theory and Intelligent Informatics, 2014." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.69, + 0.468, + 0.717 + ], + "angle": 0, + "content": "[11] D Gopika and B Azhagusundari. An analysis on ensemble methods in classification tasks. 2014." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.719, + 0.468, + 0.773 + ], + "angle": 0, + "content": "[12] Tobias Hinz, Stefan Heinrich, and Stefan Wermter. Semantic object accuracy for generative text-to-image synthesis. IEEE transactions on pattern analysis and machine intelligence, 44(3):1552-1565, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.775, + 0.468, + 0.802 + ], + "angle": 0, + "content": "[13] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. arXiv preprint arXiv:2207.12598, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.804, + 0.468, + 0.858 + ], + "angle": 0, + "content": "[14] Nupur Kumari, Richard Zhang, Eli Shechtman, and Jun-Yan Zhu. Ensembling off-the-shelf models for gan training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10651-10662, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.86, + 0.468, + 0.9 + ], + "angle": 0, + "content": "[15] Bowen Li, Xiaojuan Qi, Thomas Lukasiewicz, and Philip Torr. Controllable text-to-image generation. Advances in Neural Information Processing Systems, 32, 2019." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.115, + 0.468, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "[16] Gang Li, Heliang Zheng, Chaoyue Wang, Chang Li, Changwen Zheng, and Dacheng Tao. 3ddesigner: Towards photorealistic 3d object generation and editing with text-guided diffusion models. arXiv preprint arXiv:2211.14108, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.15, + 0.892, + 0.218 + ], + "angle": 0, + "content": "[17] Wenbo Li, Pengchuan Zhang, Lei Zhang, Qiuyuan Huang, Xiaodong He, Siwei Lyu, and Jianfeng Gao. Object-driven text-to-image synthesis via adversarial training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12174-12182, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.221, + 0.892, + 0.289 + ], + "angle": 0, + "content": "[18] Nan Liu, Shuang Li, Yilun Du, Antonio Torralba, and Joshua B. Tenenbaum. Compositional visual generation with composable diffusion models. In ECCV (17), volume 13677 of Lecture Notes in Computer Science, pages 423-439. Springer, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.291, + 0.892, + 0.345 + ], + "angle": 0, + "content": "[19] Joao Mendes-Moreira, Carlos Soares, Alipio Mário Jorge, and Jorge Freire De Sousa. Ensemble approaches for regression: A survey. Acm computing surveys (csur), 45(1):1-40, 2012." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.348, + 0.892, + 0.416 + ], + "angle": 0, + "content": "[20] Alex Nichol, Prafulla Dhariwal, Aditya Ramesh, Pranav Shyam, Pamela Mishkin, Bob McGrew, Ilya Sutskever, and Mark Chen. Glide: Towards photorealistic image generation and editing with text-guided diffusion models. arXiv preprint arXiv:2112.10741, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.418, + 0.892, + 0.473 + ], + "angle": 0, + "content": "[21] Tingting Qiao, Jing Zhang, Duanqing Xu, and Dacheng Tao. Learn, imagine and create: Text-to-image generation from prior knowledge. Advances in neural information processing systems, 32, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.476, + 0.892, + 0.543 + ], + "angle": 0, + "content": "[22] Tingting Qiao, Jing Zhang, Duanqing Xu, and Dacheng Tao. Mirrorgan: Learning text-to-image generation by redescription. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1505-1514, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.546, + 0.892, + 0.599 + ], + "angle": 0, + "content": "[23] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.603, + 0.892, + 0.657 + ], + "angle": 0, + "content": "[24] Aditya Ramesh, Mikhail Pavlov, Gabriel Goh, Scott Gray, Chelsea Voss, Alec Radford, Mark Chen, and Ilya Sutskever. Zero-shot text-to-image generation. In International Conference on Machine Learning, pages 8821-8831. PMLR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.66, + 0.892, + 0.713 + ], + "angle": 0, + "content": "[25] Ye Ren, PN Suganthan, and N Srikanth. Ensemble methods for wind and solar power forecasting—a state-of-the-art review. Renewable and Sustainable Energy Reviews, 50:82-91, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.716, + 0.892, + 0.743 + ], + "angle": 0, + "content": "[26] Lior Rokach. Ensemble-based classifiers. Artificial intelligence review, 33:1-39, 2010." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.746, + 0.892, + 0.814 + ], + "angle": 0, + "content": "[27] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684-10695, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.817, + 0.892, + 0.871 + ], + "angle": 0, + "content": "[28] Nataniel Ruiz, Yuanzhen Li, Varun Jampani, Yael Pritch, Michael Rubinstein, and Kfir Aberman. Dreambooth: Fine tuning text-to-image diffusion models for subject-driven generation. arXiv preprint arXiv:2208.12242, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.873, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[29] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.946, + 0.518, + 0.957 + ], + "angle": 0, + "content": "22601" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.148 + ], + "angle": 0, + "content": "Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.151, + 0.47, + 0.234 + ], + "angle": 0, + "content": "[30] Chitwan Saharia, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.236, + 0.471, + 0.319 + ], + "angle": 0, + "content": "[31] Christoph Schuhmann, Romain Beaumont, Richard Vencu, Cade Gordon, Ross Wightman, Mehdi Cherti, Theo Coombes, Aarush Katta, Clayton Mullis, Mitchell Wortsman, et al. Laion-5b: An open large-scale dataset for training next generation image-text models. arXiv preprint arXiv:2210.08402, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.322, + 0.47, + 0.378 + ], + "angle": 0, + "content": "[32] Jascha Sohl-Dickstein, Eric Weiss, Niru Maheswaranathan, and Surya Ganguli. Deep unsupervised learning using nonequilibrium thermodynamics. In International Conference on Machine Learning, pages 2256-2265. PMLR, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.381, + 0.47, + 0.421 + ], + "angle": 0, + "content": "[33] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. arXiv preprint arXiv:2010.02502, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.424, + 0.47, + 0.48 + ], + "angle": 0, + "content": "[34] Ming Tao, Hao Tang, Songsong Wu, Nicu Sebe, Xiao-Yuan Jing, Fei Wu, and Bingkun Bao. Df-gan: Deep fusion generative adversarial networks for text-to-image synthesis. arXiv preprint arXiv:2008.05865, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.483, + 0.471, + 0.537 + ], + "angle": 0, + "content": "[35] Sandro Vega-Pons and José Ruiz-Shulcloper. A survey of clustering ensemble algorithms. International Journal of Pattern Recognition and Artificial Intelligence, 25(03):337-372, 2011." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.541, + 0.469, + 0.596 + ], + "angle": 0, + "content": "[36] Huikai Wu, Shuai Zheng, Junge Zhang, and Kaiqi Huang. Gp-gan: Towards realistic high-resolution image blending. In Proceedings of the 27th ACM international conference on multimedia, pages 2487-2495, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.599, + 0.47, + 0.655 + ], + "angle": 0, + "content": "[37] Tao Xu, Pengchuan Zhang, Qiuyuan Huang, Han Zhang, Zhe Gan, Xiaolei Huang, and Xiaodong He. Attngan: Fine-grained text to image generation with attentional generative adversarial networks. Cornell University - arXiv, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.657, + 0.47, + 0.725 + ], + "angle": 0, + "content": "[38] Linjie Yang, Ping Luo, Chen Change Loy, and Xiaou Tang. A large-scale car dataset for fine-grained categorization and verification. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3973-3981, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.729, + 0.47, + 0.771 + ], + "angle": 0, + "content": "[39] Pengyi Yang, Yee Hwa Yang, Bing B Zhou, and Albert Y Zomaya. A review of ensemble methods in bioinformatics. Current Bioinformatics, 5(4):296-308, 2010." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.774, + 0.47, + 0.828 + ], + "angle": 0, + "content": "[40] Hui Ye, Xiulong Yang, Martin Takac, Rajshekhar Sunderraman, and Shihao Ji. Improving text-to-image synthesis using contrastive learning. arXiv preprint arXiv:2107.02423, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.831, + 0.47, + 0.9 + ], + "angle": 0, + "content": "[41] Han Zhang, Jing Yu Koh, Jason Baldridge, Honglak Lee, and Yinfei Yang. Cross-modal contrastive learning for text-to-image generation. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 833-842, 2021." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.893, + 0.16 + ], + "angle": 0, + "content": "[42] Zizhao Zhang, Yuanpu Xie, and Lin Yang. Photographic text-to-image synthesis with a hierarchically-nested adversarial network. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 6199-6208, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.164, + 0.893, + 0.218 + ], + "angle": 0, + "content": "[43] Jing Zhao, Heliang Zheng, Chaoyue Wang, Long Lan, Wanrong Huang, and Wenjing Yang. Null-text guidance in diffusion models is secretly a cartoon-style creator. arXiv preprint arXiv:2305.06710, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.221, + 0.893, + 0.274 + ], + "angle": 0, + "content": "[44] Ying Zhao, Jun Gao, and Xuezhi Yang. A survey of neural network ensembles. In 2005 international conference on neural networks and brain, volume 1, pages 438-442. IEEE, 2005." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.277, + 0.893, + 0.345 + ], + "angle": 0, + "content": "[45] Minfeng Zhu, Pingbo Pan, Wei Chen, and Yi Yang. Dm-gan: Dynamic memory generative adversarial networks for text-to-image synthesis. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 5802-5810, 2019." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.893, + 0.345 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.946, + 0.52, + 0.957 + ], + "angle": 0, + "content": "22602" + } + ] +] \ No newline at end of file diff --git a/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/40801689-afc7-4c4a-b4e3-8cbca2d70a56_origin.pdf b/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/40801689-afc7-4c4a-b4e3-8cbca2d70a56_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..1460e6c4a0e3c1b15fde57d5ee97b96277cbe697 --- /dev/null +++ b/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/40801689-afc7-4c4a-b4e3-8cbca2d70a56_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:a3aa244577bf4055a76d1900606ad26d29f35cff917bce0e46b9d48ebe120c89 +size 8679303 diff --git a/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/full.md b/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/full.md new file mode 100644 index 0000000000000000000000000000000000000000..2a6a8915045acc6824f0f10d90d9f5d2f36d6dc9 --- /dev/null +++ b/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/full.md @@ -0,0 +1,337 @@ +# MagicFusion: Boosting Text-to-Image Generation Performance by Fusing Diffusion Models + +Jing Zhao $^{1*}$ , Heliang Zheng $^{2}$ , Chaoyue Wang $^{2}$ , Long Lan $^{1}$ , Wenjing Yang $^{1\dagger}$ + +$^{1}$ National University of Defense Technology, Changsha, China, + +$^{2}$ JD Explore Academy, Beijing, China + +{zhaojing,long.lan,wenjing.yang}@nudt.edu.cn,zhenghllj@gmail.com,chaoyue.wang@outlook.com + +![](images/c53a296ef2f0ac2479375b6f989d973ad745e0409f3bdd1aa7efe795781ff089.jpg) +Figure 1: "MagicFusion". Given two diffusion models, our method can preserve the strengths of each individual model. (a) A general model [27] + a fine-grained car model to achieve fine-grained generation with complex scenes. (b) A general model + a DreamBooth model [28] to recontextualize specific objects with well-preserved details. (c) A general model + a cartoon model to generate creative scenes with photorealistic fidelity. + +![](images/4015815acb025edfc67f3fa82bc8d01d1b7f9971da5177fda74d2f01126cc2fd.jpg) + +![](images/5e1ee9391e257e3bdb144457538a57f38401c9c775794644b5b98f50ab16a968.jpg) + +# Abstract + +The advent of open-source AI communities has produced a cornucopia of powerful text-guided diffusion models that are trained on various datasets. While few explorations have been conducted on ensembling such models to combine their strengths. In this work, we propose a simple yet effective method called Saliency-aware Noise Blending (SNB) that can empower the fused text-guided diffusion models to achieve more controllable generation. Specifically, we experimentally find that the responses of classifier-free guidance are highly related to the saliency of generated images. Thus we propose to trust different mod + +els in their areas of expertise by blending the predicted noises of two diffusion models in a saliency-aware manner. SNB is training-free and can be completed within a DDIM sampling process. Additionally, it can automatically align the semantics of two noise spaces without requiring additional annotations such as masks. Extensive experiments show the impressive effectiveness of SNB in various applications. The project page is available at https://magicfusion.github.io/. + +# 1. Introduction + +In recent years, significant progress has been made in image generation [29, 6, 24, 23, 27, 20, 29, 5] thanks to breakthroughs in diffusion models [32, 29, 33] and large- + +scale training [24, 20, 29, 5], as well as the contributions of open-source AI communities. Pre-trained large models have become an invaluable resource in this field. One of the most exciting developments has been text-guided diffusion models [24, 20, 29, 27]. A wide range of powerful text-guided diffusion models trained on various datasets has been publicly released. For example, general models (e.g., stable diffusion v1-4, v1-5, v2-1, etc. [27]) trained on large-scale multimodal datasets like LAION 5B [31], as well as more specialized models (e.g., Anything-v3) trained on cartoon and anime datasets or fine-grained categories such as cars [38]. There are even fine-tuned models designed for specific objects [28]. The vast amounts of data and computational cost have enabled these models to achieve impressive capabilities in various fields. However, few explorations have been conducted on ensembling such models to combine their strengths. + +Some works propose to add special symbols or signature phrases when fine-tuning models on new datasets [1]. This approach enables the model to generate novel image distributions while retaining its ability to generate from the original data distribution. However, there has been limited discussion on how to effectively combine the generation capabilities of these two distributions. One intuitive method for integrating the capabilities of two models involves taking a weighted average of their predicted noises [2]. However, such kind of fusions often fails to fully preserve the strengths of each model. Blended diffusion [3] proposes to spatially blend a noisy image and a predicted one, which has been explored in image editing tasks. However, this typically requires specifying a mask to edit particular objects, and few discussions have been conducted to blend the noises of two diffusion models. + +In this work, we propose a simple yet effective method called Saliency-aware Noise Blending (SNB) that can empower the fused text-guided diffusion models to achieve more controllable generation. Specifically, we integrate two diffusion models by spatially blending the predicted noises. Our insight is to trust different models in their areas of expertise, thus the strengths of each individual model can be preserved. To obtain diffusion models' areas of expertise, we revisit the classifier-free guidance [13], which is widely adopted in text-guided diffusion models to enhance the difference between a given text and a null text in the predicted noise space. We experimentally find that the responses of classifier-free guidance are highly related to the saliency of generated images. To this end, we propose Saliency-aware Noise Blending that blends the predicted noises of two diffusion models based on their responses to classifier-free guidance. + +SNB is training-free and can be completed within a DDIM sampling [33] process. Additionally, it can automatically align the semantics of two noise spaces without + +requiring additional annotations such as masks. Our main contributions can be summarised as follows: + +- We propose to fuse two well-trained diffusion models to achieve more powerful image generation, which is a novel and valuable topic. +- We propose a simple yet effective Saliency-aware Noise Blending method for text-guided diffusion models fusion, which can preserve the strengths of each individual model. +- We conduct extensive experiments on three challenging applications (i.e., a general model + a cartoon model, a fine-grained car model, and a Dream-Booth [28] model), and prove that SNB can significantly empower pre-trained diffusion models. + +The remainder of the paper is organized as follows. We describe related work in Section 2 and introduce our proposed SNB method in Section 3. An evaluation of three applications is presented in Section 4, followed by the results and comparisons with other methods in Section 5. Finally, a comprehensive summary of the paper is presented and an analysis of the limitations is provided in Section 6. + +# 2. Related Works + +# 2.1. Text-to-image synthesis + +Text-guided image generation plays a significant role in image generation [43, 16, 7, 12, 36, 15, 17, 21, 22, 24, 42]. Previous works mainly focus on GAN-based [10] models and small-scale image-text datasets [45, 34, 37, 41, 40]. Since Transformer-based autoregressive models [8, 24] were proposed, more and more attention has been attracted to large-scale training. The emergence of denoising diffusion models is another milestone, which significantly boosts the generation fidelity [23, 30, 20, 27]. Notably, Stable Diffusion [27] is publicly released, enabling a large number of variants that are fine-tuned on different datasets. The vast amounts of data and computational cost have enabled these models to achieve impressive capabilities in various fields. However, few explorations have been conducted on assembling such models to combine their strengths. + +# 2.2. Model Ensembling + +Model ensembling is a powerful technique to distill the knowledge of multiple models and boost the performance, which is widely obtained in image understanding tasks, i.e., classification problems [44, 26, 11, 39], regression problems [19, 25] and clustering [35]. White such methods are hard to be adapted to generative models due to the large and complex image pixel space. Vision-aided GAN [14] proposes ensembling pre-trained vision models as a loss to guide the optimization of a generator. eDiff-I [4] proposes to ensemble different denoisers in different timesteps to improve the overall performance of image generation. In this + +![](images/4901b11e721ec37d70191db2a3f1e3d05d47a795f806d673ff60f866bb004624.jpg) +Figure 2: An overview of our Saliency-aware Noise Blending (SNB). Given two diffusion models, we first design a "Noise to salience map" module to obtain salience maps. After that, we can generate saliency-aware masks based on the salience maps. Finally, we blend the diffusion models in the noise space according to the mask. $(^{*})\hat{\epsilon}_{g}$ and $\hat{\epsilon}_e$ are noises instead of noisy images, and we add the image here just for visualization. + +work, we propose to ensemble different pre-trained diffusion models in a novel dimension, i.e., spatial, which can be applied to various scenarios. + +# 3. Method + +In this section, we introduce our proposed saliency-aware noise blending. Specifically, we first review the widely obtained classifier-free guidance, after that, we revisit such guidance and experimentally find that the classifier-free guidance is secretly a saliency indicator. Based on the salience map, we can obtain a saliency-aware mask, which is further used to guide the blending of the noise of two diffusion models. Figure 2 show the whole pipeline, and more details can be found in the following. + +# 3.1. Preliminaries + +Given a pre-trained text-guided diffusion model, we can generate images by a DDPM/DDIM sampling process, which progressively converts a Gaussian noise into an image for $T$ timesteps. Take the DDIM sampling for example, a denoising step can be denoted as: + +$$ +x _ {t - 1} = \sqrt {\bar {\alpha} _ {t - 1}} \left(\frac {x _ {t} - \sqrt {1 - \bar {\alpha} _ {t}} \hat {\epsilon}}{\sqrt {\bar {\alpha} _ {t}}}\right) + \sqrt {1 - \bar {\alpha} _ {t - 1}} \hat {\epsilon}, \tag {1} +$$ + +where $t$ indicates the timestep, $x$ is the noisy image, $\bar{\alpha}$ is related to a pre-defined variance schedule, and $\hat{\epsilon}$ is the predicted noise. The predicted noise can be re-modulated by classifier-free guidance [13], which is designed to extrapolate the output of the model in the direction of $\epsilon_{\theta}(x_t|c)$ and + +away from $\epsilon_{\theta}(x_t|\varnothing)$ as follows: + +$$ +\hat {\epsilon} = \epsilon_ {\theta} \left(x _ {t} | \varnothing\right) + s \cdot \left(\epsilon_ {\theta} \left(x _ {t} \mid c\right) - \epsilon_ {\theta} \left(x _ {t} | \varnothing\right)\right), \tag {2} +$$ + +where $\epsilon_{\theta}$ is the pretrained model, $c$ is the text condition, $\varnothing$ is a null text, $s$ is the guidance weight and increasing $s > 1$ strengthens the effect of guidance. + +# 3.2. Noise to Salience Map + +We experimentally find that the classifier-free guidance introduced above is secretly a saliency indicator. Specifically, $\epsilon_{\theta}(x_t|c) - \epsilon_{\theta}(x_t|\varnothing)$ in Eqn. 2 indicates the difference between a conditional prediction and an unconditional prediction, thus the objects and scenes appeared in the text condition would be emphasized with a large value, especially when we adopt a large guidance scale $s$ (e.g., 10-100). We visualize the re-modulated noises of Eqn. 2 and find that the important region does have high responses. To this end, we propose to obtain a salience map by the following operation: + +$$ +\Lambda \left(\epsilon_ {t}\right) = \operatorname {B l u r} \left(\operatorname {A b s} \left(\epsilon_ {\theta} \left(x _ {t} \mid c\right) - \epsilon_ {\theta} \left(x _ {t} \mid \varnothing\right)\right)\right) \tag {3} +$$ + +where $\Lambda (\epsilon_t)$ represents the salience map, $Abs(\cdot)$ calculates the absolute value of the input variables, and $Blur(\cdot)$ is used to smooth the high-frequency noise, which can eliminate local interference responses and leverage the coherence of adjacent regions. + +# 3.3. Saliency-aware Blending + +The above discussions are all about a single diffusion model, and now let us move to the next stage, i.e., obtaining a blending mask based on two models' salience maps. + +Given a general model and an expert model, we can obtain the corresponding salience maps by Eqn. 3, which are denoted as $\Lambda^g$ and $\Lambda^e$ , respectively. We first normalize these salience maps by the softmax function: + +$$ +\Lambda^ {g ^ {\prime}} = \operatorname {s o f t m a x} (k ^ {g} * \Lambda^ {g}) \tag {4} +$$ + +$$ +\Lambda^ {e ^ {\prime}} = \operatorname {s o f t m a x} \left(k ^ {e} * \Lambda^ {e}\right), +$$ + +where $k^g$ and $k^e$ are hyper-parameters, i.e., temperature of the softmax. Note that the softmax here ensures the sum of each salience map to be a constant (i.e., 1), which means each model must focus on some regions instead of having a high response everywhere. When we integrate a general model and an expert model, the salience map of the general model tends to cover multiple objects to compose the whole scene, while the expert model tends to have a higher response to a specific object. Thus we obtain a blending mask $\mathcal{M}$ by comparing these two salience maps: + +$$ +\mathcal {M} = \arg \max \left(\Lambda^ {g ^ {\prime}}, \Lambda^ {e ^ {\prime}}\right) \tag {5} +$$ + +The saliency-aware mask is an effective guide to perform noise blending, which consists of binary values of 0 and 1, corresponding to the noise $\epsilon_{g}$ and $\epsilon_{e}$ respectively. We can obtain the fused noise as follows: + +$$ +\hat {\epsilon} = \mathcal {M} \odot \hat {\epsilon} _ {g} + (1 - \mathcal {M}) \odot \hat {\epsilon} _ {e}, \tag {6} +$$ + +where $\odot$ denotes Hadamard (element-wise) Product, and we omit $t$ for simplicity. In the specific implementation process, the fusion strategy is executed only when $t \leq t_s$ , ensuring that the fusion results possess the fundamental structure of images generated by the general model. Algorithm 1 summarizes the process of the saliency-aware noise blending algorithm. + +Additional explanations on the three applications. In the three applications (i.e., a general model + a fine-grained model, a DreamBooth model, and a cartoon model) of this work, the expert model of the former two focuses on a specific object, while the last one contributes to the global structure of the generated image. In the last application, the cartoon model tends to focus on low-frequency structure and the general model focuses on high-frequency details. Thus the blended mask is not object-level, and we remove the blur operation in Eqn. 3 to facilitate such blending. + +Clarification of technique novelty. The overall process of this algorithm is quite simple, yet it is non-trivial by solving two challenges. Firstly, we leverage the classifier-free guidance to automatically identify each model's areas of expertise. The introduction of the hyper-parameter $k$ provides improved controllability for blending the two sources of images, thereby enabling greater creativity and flexibility in image generation based on SNB. Secondly, the task of obtaining saliency response values that are closely linked + +Algorithm 1 Saliency-aware Noise Blending + +Input: Two pre-trained models $\epsilon_{\theta_g}$ and $\epsilon_{\theta_e}$ , along with two prompts, $y_{g}$ and $y_{e}$ . gradient scale $s$ in Eq.(2). Hyperparameters $k^a$ and $k^b$ in Eq. (4) and fusion time $t_s$ . + +Output: The fused image $x_0$ + +1: $x_{T}\sim \mathcal{N}(0,I)$ +2: for $t$ from $T$ to 0 do +3: if $t > t_{s}$ then +4: $\epsilon_{t} = \epsilon_{t_{g}}$ +5: else +6: $\epsilon_{t_q} = \epsilon_{\theta_q}(x_t|c_g),\epsilon_{t_e} = \epsilon_{\theta_e}(x_t|c_e)$ +7: get $\Lambda^g (\epsilon_{t_g})$ and $\Lambda^{e}(\epsilon_{t_{e}})$ according to Eq.(3). +8: get $\Lambda^{g'}(\epsilon_{t_g})$ and $\Lambda^{e'}(\epsilon_{t_e})$ via Eq. (4). +9: $\mathcal{M} = \arg \max (\Lambda^{a'},\Lambda^{b'})$ +10: get the noise generated by classifier-free guidance $\hat{\epsilon}_{t_g}$ and $\hat{\epsilon}_{t_e}$ via Eq.(2). +11: $\epsilon_{t} = \mathcal{M}\odot \hat{\epsilon}_{t_{g}} + (1 - \mathcal{M})\odot \hat{\epsilon}_{t_{e}}$ +12: end if +13: $x_{t - 1}\gets \epsilon_t$ via Eq.(1) +14: end for +15: return $x_0$ . + +to prompt content is highly non-trivial. Secondly, in each sampling step, the two models take as input the blended $x_{t}$ , enabling automatic semantic alignment of the two models' noise space. We believe our exploration would contribute to the community and benefit the leveraging of pre-trained diffusion models. + +# 4. Applications + +In order to evaluate the effectiveness of our proposed method, we conduct experiments on three challenging applications. 1) Fine-grained Fusion, i.e., fusing a general and a fine-grained model to achieve fine-grained generation with complex scenes. 2) Recontextualization, i.e., fusing a general and a DreamBooth [28] model allows for the recontextualization of specific objects with well-preserved details. 3) Cross-domain Fusion, i.e., fusing a general and a cartoon model to combine the creative advantages of the cartoon model to generate complex scenes and the photorealistic fidelity of the general model. These experiments will allow us to evaluate the performance of our method across a range of scenarios and provide valuable insights into the strengths and limitations of our approach. + +# 4.1. Application 1: Fine-grained Fusion + +The stable diffusion model [27] trained on large-scale multimodal datasets like LAION 5B [31] has shown impressive performance on general text-to-image synthesis. In our experiments, we use the publicly released stable diffusion v1-4. Meanwhile, fine-grained car models trained on (an + +![](images/937320c0d3cdb1c35ca2a49f8f451d29728488b2ea6e569a57a8c9642b862dd1.jpg) +Figure 3: Application 1: visualization results of Fine-grained Fusion. Our method enables fine-grained generation with complex scenes. + +extension of) CompCars [38] can generate fine-grained car images with specific colors, viewpoints, types, brands, and models. + +For instance, a scene description like "a photo of a red car in a snowy forest" can be fed into the general model, resulting in a corresponding image as shown in the first left column of Figure 3. Similarly, a specific car description like "red hatchback Audi (imported) Audi A1 2010 e-tron" can be fed into the car model, generating an Audi car that matches the prompt. To fuse the noise of the two models during the denoising sampling process, we propose the SNB method, which can produce a fused image of a red Audi hatchback car in a snowy forest. The fusion results of the general model and the fine-grained car model are illustrated in Figure 3, showing the ability to replace the car in the scene with a specific one while retaining the original scene unchanged. Notably, our SNB does not require additional annotations to specify the car's position in the original image, enabling automatic semantic alignment. + +# 4.2. Application 2: Recontextualization + +Recontextualization, or named personalizing text-to-image generation, is proposed in previous works [9, 28], which aims to generate a creative scene for a specific ob + +ject/concept. DreamBooth [28] proposes to fine-tune a diffusion model on several given images together with a placeholder word to enable the model to generate a specific object/concept. In this application, we integrate a general and a DreamBooth [28] model to allow for the recontextualization of specific objects with well-preserved details. + +Specifically, we first fine-tune the general model using multiple images of the target object. Thus the fine-tuned model can represent the specific object with the placeholder "[ ]" in the prompt. Next, we get through a sentence that describes a complex scene and "a photo of a [ ] < class >" into SNB to integrate the general model and the Dream-Booth model. Results can be found in Figure 4. It can be observed that our method can put a specific object with rich details into a complex scene. + +# 4.3. Application 3: Cross-domain Fusion + +Different models have distinct advantages when it comes to generating images with specific styles. For example, cartoon models are particularly skilled at creative composition and can generate scenes that are rarely observed in real-world scenarios. When we strive to generate images with unique and imaginative compositions, we can integrate a cartoon model to generate a distinctive scene and a general + +![](images/6d5663e63b0bb0ef7dce7909f563feb1179132e938474ae411e2b8de8d6738ef.jpg) + +![](images/3fe875f2c4c09105dfb6af345ec447f3e2f6fb7b54a526f1ced8f96496f8dcc5.jpg) +[ ] on a rock with snow mountain in the background. + +![](images/4a13bb59ebb65187504b8c7a648e8172e9fe90be8e909bb89ed50696eeb80ce5.jpg) + +![](images/45b7ac88bda42a346c6adec4f1179715b1976a88e4a5ddfa3fc7a4afa5dff9d4.jpg) + +![](images/c71c22d7f9458505e133dfb564f0c5cf05987c3f6fad3e94a7e064f9af3873b2.jpg) + +![](images/6801c958173bf18ccf56787924811b40b3d72c0cd2cc27cd0d45048ef1d1a539.jpg) + +![](images/d407e9c57a1a1c9095c780b0804526436a5ceee96559329458cca4f8efbb06ee.jpg) + +![](images/deb8230afd6a20a9f1ad36dada99a65bd123866ccaba6b615427a2a3e2c19138.jpg) + +![](images/71df950b17e0627e13ff035d8262d89f858a78b290bec10ef0ceda65ddac58e0.jpg) +Figure 4: Application 2: visualization results of Recontextualization. Our method can recontextualize specific objects in complex scenes with well-preserved details. + +![](images/d8b30b64a3a857632cc673cb51f7427ffa2012c80958ecf25cd94d4525d4fc71.jpg) + +![](images/548757c867aaadd4b4b46ab6481f07a745e855ddd38473cdbd288106aaeeacc3.jpg) + +![](images/868be75c33ed82c789b69b490e3012336ada6357c27e4796dd39d0a837e9975c.jpg) + +![](images/956420edf4cd12814549833214ed1303273b823ddcb130ac5c3a91f9cebe68a9.jpg) +Figure 5: Application 3: visualization results of Cross-domain Fusion. Our method can combine the creative advantages of the cartoon model to generate complex scenes and the photorealistic fidelity of the general model. + +model to make the content more realistic. + +In this application, the same textual description of a scene is fed into both the general and the cartoon models. This allows us to generate two sets of noise that correspond to the same content but different styles during the sampling process. By fusing these two sets of noise, SNB generates images that exhibit both a creative composition and realistic content. As shown in Figure 5, our proposed SNB provides a powerful tool for achieving the balance of creative and realistic, and we believe that such a tool has the potential to benefit a wide range of applications in various fields, such as art and AI-aided design. + +# 5. Results and Comparisons + +# 5.1. Compared to the General Model + +The stable diffusion model is a widely used and versatile generative model in computer vision that can generate a diverse range of images based on prompts. However, when the prompts contain multiple content subjects, the general model's generation performance can become challenging, especially when the combination of these subjects is rare in real-world scenes. This limitation can result in missing subjects in the generated images, as observed in Application 1, where the general model fails to capture both the car and + +![](images/71060445afd3f71a4bf54c6bd4631a7adc56eb14aa6e71bd7e79b00f927803de.jpg) +Figure 6: Compared to the general model. The general model fails to precisely generate fine-grained objects and tends to miss some objects when the prompt is full of details. + +![](images/1ff4c252e02dde5cca65df01afa591d1d19ab5b6075f95fcc2bdffc1252de5b2.jpg) +Figure 7: Compared to DreamBooth [28]. Dreambooth struggles with preserving the details of the given objects, especially for complex and lengthy prompts. + +the seagulls in the same scene. A similar issue is observed in Application 3 (Figure 1), where the general model cannot produce scenes that are uncommon in real-life, such as a lion wearing a crown (Figure 6). In addition, the general model has difficulty understanding the semantics of certain prompts, as observed in the case of "a bee is making honey" in Figure 5, where the model only combines the bee and honey in the same scene. + +The proposed SNB can address these limitations, which integrates a specialized model, such as a model that focuses on cars in Application 1, or a cartoon model in Application 3, to improve the accuracy and realism of image generation. By leveraging the strengths of both the general and specialized models, our proposed approach can generate visually appealing and semantically rich images. This approach has the potential to advance the field of computer vision by enabling more sophisticated and realistic image generation. + +# 5.2. Compared to Dreambooth + +Dreambooth [28] presents an approach for synthesizing novel renditions of a given subject using a few images of the subject and the guidance of a text prompt, i.e., recon + +textualization. However, it is challenging for Dreambooth to handle certain creative scene compositions, such as “a [] backpack on the moon.” Our empirical investigation reveals that Dreambooth struggles with integrating specific subjects into the scene, particularly in cases where the scenario is uncommon in reality. As illustrated in Figure 7, Dreambooth frequently produces images that either lack or exhibit inconsistencies in terms of specific subjects in such scenarios. In contrast, our approach excels at integrating a specific subject into the scene while maintaining fidelity to the prompt. Although Dreambooth can generate contextually relevant images for brief prompts like “a [] bag on a garden bench,” it may not accurately capture the finer details of the subject, such as the graphic texture of the bag. In contrast, our approach not only generates images that adhere to the prompt but also reproduces subject details with greater accuracy. + +# 5.3. Compared to Annotated Masks + +Blended-Diffusion [3] firstly propose to blend the noisy image in each sampling step based on a given mask for image editing. Such a method can neither handle applica + +![](images/ead9e6c9fb6b83d2cd1eee80a6c546e77a66ba3a7fb4c1b600e0984aad70b902.jpg) +Figure 8: Compared to annotated masks. Our saliency-aware mask achieves better composing performance, e.g., generating snow on the car. + +![](images/167a05b5a8a58f35dcc27a0fef827436dbd354ea44169497c68330caa77a02a4.jpg) + +![](images/f0a07eba5f8255da381de24fb4ea593582c56421c753f472ef8e471d5bd363fe.jpg) +Cross-domain Fusion: A bee is making honey + +![](images/b7c16dcb7dc76be9b258e11c5e7e462f5d89e23ad68ac22dc40e05f4c46b52cf.jpg) +Recontextualization: [ ] on the sofa in the living room, decorated with green plants and sunny +Figure 9: Compared to weighted sum. Directly averaging the two noises cannot well preserve each model's strengths and leads to cluttered image content. + +tions like cross-domain fusion nor perform well on a mixed object and scene content, such as "a car in a snowy forest." As depicted in Figure 8, a comparison between our method and a mask-based approach demonstrates that our SNB method accurately preserves detailed subject features influenced by the scene, like the snow on the car's hood and wheels. In contrast, the mask-based method replaces the entire car area, resulting in a loss of subject details within the scene. Overall, our SNB yields more natural and realistic results when editing or replacing scene content, particularly in scenarios with mixed object and scene content. + +# 5.4. Compared to Weighted Sum + +The success of SNB hinges upon its ability to create a high-quality mask based on the noise generated by the two models, which is then used to determine content coverage and retention. As shown in Figure 9, the experimental re + +sults of SNB and the fusion method that directly averages the two noises differ significantly. When the weighted sum of two noises is used, the resulting image content appears cluttered and lacks the desired semantic alignment. In contrast, our SNB method outperforms the direct averaging method by achieving precise semantic alignment, resulting in more accurate and realistic image content. + +It is worth noting that, CDM [18] is belong to the case of weighted sum, which treats two noises equally in different regions, while we trust different models in different regions by designing a saliency-aware fusion mechanism. We further show the comparison results with CDM in Fig. 10. CDM fails to generate accurate car images in the case of complex prompts (left) and tends to produce conceptually mixed images or exhibits unstable performance (right). In contrast, our proposed method can accurately generate specified images of cars as well as vivid depictions + +![](images/5300f61b98b2de7dcef81ecc4a3c08aecb1aeffb169b99faff5671702cc92ae3.jpg) +Figure 10: Comparisons with CDM. In the case of complex prompts (left), CDM fails to generate accurate car images. Moreover, CDM tends to produce conceptually mixed images (mid) or exhibits unstable performance (right). + +
Text-Image SimilarityImage Similarity
App. 1 ↑App. 3 ↑App. 2 ↑
Ours31.1832.760.8401
Baseline29.5631.010.7582
+ +Table 1: The CLIP-based Quantitative Metrics. + +
App. 1App. 2App. 3
Ours better81.4%84.7%79.3%
+ +Table 2: Human evaluations. + +of lions wearing crowns. Overall, our method demonstrates significantly better performance compared to CDM. + +# 5.5.Quantitative Metrics + +We conducted quantitative evaluations for three corresponding applications. Specifically, we generated 5k test samples for each application to calculate the CLIP-based score. For application 1 and application 3, we measured the similarity between the generated images and the corresponding prompts in terms of Text-Image Similarity; for application 2, we calculated the similarity between the recontextualized images and the input images, which is referred to as Image Similarity. The evaluation results are presented in Table 1. Stable diffusion serves as the baseline for application 1 and application 3, while Dreambooth [28] serves as the baseline for application 2. Based on the results, it can be concluded that our method has demonstrated improved performance across all three applications. + +In addition, we also conducted 500 human evaluations for each application and presented the results in Table 2. In application 1 and application 3, we compare our model to stable diffusion, and in application 2, we compare it to Dreambooth. The data indicate that for all three applications, the majority of the participants regarded the images generated by our method as superior in quality. + +![](images/0ed7c819e06ef13978e427a7e5b24dc22ee47eb4d3f04f2646edd9ab6f1cf61f.jpg) +Figure 11: Failure cases. Misalignments may appear due to the various car size. + +# 6. Conclusion + +In this work, we study the problem of integrating pretrained text-guided diffusion models to achieve more controllable generation. We propose a simple yet effective Saliency-aware Noise Blending (SNB) to preserve the strengths of each individual model. Extensive experiments on three challenging applications (i.e., a general model + a cartoon model, a fine-grained car model, and a Dream-Booth model) show that SNB can significantly empower pre-trained diffusion models. With the rapid development of pre-trained large generative models, we believe our work is of great value. + +Limitations. Although our method has demonstrated significant performance improvements, it may not be applicable in certain scenarios. The advantage of SNB is its ability to form automatic masks based on saliency response values; however, when the difference in object size between the two merged images is too large, semantic alignment can be difficult to achieve. As shown in Figure 11, when the general model produces cars that are either too large or too small, the results display misaligned semantic positions. In the future, we will keep on studying the integration of different large generative models and extend our method to more general settings. + +# Acknowledgments + +This work was partially supported by the National Natural Science Foundation of China: No. 91948303-1, 611803375, No. 61803375, No. 12002380, No. 62106278, No. 62101575, No. 61906210; the Postgraduate Scientific Research Innovation Project of Hunan Province: QL20210018 and the National Key R&D Program of China (2021ZD0140301). + +# References + +[1] Fine-tuned stable diffusion model trained on screenshots from a popular animation studio. https://huggingface.co/nitrosocke/mo-di-diffusion.2022. +[2] Merging two diffusion models. https://stable-diffusion-art.com/models/#merging_two_models. 2022. +[3] Omri Avrahami, Dani Lischinski, and Ohad Fried. Blended diffusion for text-driven editing of natural images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18208-18218, 2022. +[4] Yogesh Balaji, Seungjun Nah, Xun Huang, Arash Vahdat, Jiaming Song, Karsten Kreis, Miika Aittala, Timo Aila, Samuli Laine, Bryan Catanzaro, et al. eDIFF-I: Text-to-image diffusion models with an ensemble of expert denoisers. arXiv preprint arXiv:2211.01324, 2022. +[5] Huiwen Chang, Han Zhang, Jarred Barber, AJ Maschinot, Jose Lezama, Lu Jiang, Ming-Hsuan Yang, Kevin Murphy, William T Freeman, Michael Rubinstein, et al. Muse: Text-to-image generation via masked generative transformers. arXiv preprint arXiv:2301.00704, 2023. +[6] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Advances in Neural Information Processing Systems, 34:8780-8794, 2021. +[7] Ming Ding, Zhuoyi Yang, Wenyi Hong, Wendi Zheng, Chang Zhou, Da Yin, Junyang Lin, Xu Zou, Zhou Shao, Hongxia Yang, et al. Cogview: Mastering text-to-image generation via transformers. Advances in Neural Information Processing Systems, 34:19822-19835, 2021. +[8] Patrick Esser, Robin Rombach, and Bjorn Ommer. Taming transformers for high-resolution image synthesis. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 12873-12883, 2021. +[9] Rinon Gal, Yuval Alaluf, Yuval Atzmon, Or Patashnik, Amit H Bermano, Gal Chechik, and Daniel Cohen-Or. An image is worth one word: Personalizing text-to-image generation using textual inversion. arXiv preprint arXiv:2208.01618, 2022. +[10] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. Journal of Japan Society for Fuzzy Theory and Intelligent Informatics, 2014. +[11] D Gopika and B Azhagusundari. An analysis on ensemble methods in classification tasks. 2014. +[12] Tobias Hinz, Stefan Heinrich, and Stefan Wermter. Semantic object accuracy for generative text-to-image synthesis. IEEE transactions on pattern analysis and machine intelligence, 44(3):1552-1565, 2020. +[13] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. arXiv preprint arXiv:2207.12598, 2022. +[14] Nupur Kumari, Richard Zhang, Eli Shechtman, and Jun-Yan Zhu. Ensembling off-the-shelf models for gan training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10651-10662, 2022. +[15] Bowen Li, Xiaojuan Qi, Thomas Lukasiewicz, and Philip Torr. Controllable text-to-image generation. Advances in Neural Information Processing Systems, 32, 2019. + +[16] Gang Li, Heliang Zheng, Chaoyue Wang, Chang Li, Changwen Zheng, and Dacheng Tao. 3ddesigner: Towards photorealistic 3d object generation and editing with text-guided diffusion models. arXiv preprint arXiv:2211.14108, 2022. +[17] Wenbo Li, Pengchuan Zhang, Lei Zhang, Qiuyuan Huang, Xiaodong He, Siwei Lyu, and Jianfeng Gao. Object-driven text-to-image synthesis via adversarial training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12174-12182, 2019. +[18] Nan Liu, Shuang Li, Yilun Du, Antonio Torralba, and Joshua B. Tenenbaum. Compositional visual generation with composable diffusion models. In ECCV (17), volume 13677 of Lecture Notes in Computer Science, pages 423-439. Springer, 2022. +[19] Joao Mendes-Moreira, Carlos Soares, Alipio Mário Jorge, and Jorge Freire De Sousa. Ensemble approaches for regression: A survey. Acm computing surveys (csur), 45(1):1-40, 2012. +[20] Alex Nichol, Prafulla Dhariwal, Aditya Ramesh, Pranav Shyam, Pamela Mishkin, Bob McGrew, Ilya Sutskever, and Mark Chen. Glide: Towards photorealistic image generation and editing with text-guided diffusion models. arXiv preprint arXiv:2112.10741, 2021. +[21] Tingting Qiao, Jing Zhang, Duanqing Xu, and Dacheng Tao. Learn, imagine and create: Text-to-image generation from prior knowledge. Advances in neural information processing systems, 32, 2019. +[22] Tingting Qiao, Jing Zhang, Duanqing Xu, and Dacheng Tao. Mirrorgan: Learning text-to-image generation by redescription. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1505-1514, 2019. +[23] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022. +[24] Aditya Ramesh, Mikhail Pavlov, Gabriel Goh, Scott Gray, Chelsea Voss, Alec Radford, Mark Chen, and Ilya Sutskever. Zero-shot text-to-image generation. In International Conference on Machine Learning, pages 8821-8831. PMLR, 2021. +[25] Ye Ren, PN Suganthan, and N Srikanth. Ensemble methods for wind and solar power forecasting—a state-of-the-art review. Renewable and Sustainable Energy Reviews, 50:82-91, 2015. +[26] Lior Rokach. Ensemble-based classifiers. Artificial intelligence review, 33:1-39, 2010. +[27] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684-10695, 2022. +[28] Nataniel Ruiz, Yuanzhen Li, Varun Jampani, Yael Pritch, Michael Rubinstein, and Kfir Aberman. Dreambooth: Fine tuning text-to-image diffusion models for subject-driven generation. arXiv preprint arXiv:2208.12242, 2022. +[29] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed + +Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022. +[30] Chitwan Saharia, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022. +[31] Christoph Schuhmann, Romain Beaumont, Richard Vencu, Cade Gordon, Ross Wightman, Mehdi Cherti, Theo Coombes, Aarush Katta, Clayton Mullis, Mitchell Wortsman, et al. Laion-5b: An open large-scale dataset for training next generation image-text models. arXiv preprint arXiv:2210.08402, 2022. +[32] Jascha Sohl-Dickstein, Eric Weiss, Niru Maheswaranathan, and Surya Ganguli. Deep unsupervised learning using nonequilibrium thermodynamics. In International Conference on Machine Learning, pages 2256-2265. PMLR, 2015. +[33] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. arXiv preprint arXiv:2010.02502, 2020. +[34] Ming Tao, Hao Tang, Songsong Wu, Nicu Sebe, Xiao-Yuan Jing, Fei Wu, and Bingkun Bao. Df-gan: Deep fusion generative adversarial networks for text-to-image synthesis. arXiv preprint arXiv:2008.05865, 2020. +[35] Sandro Vega-Pons and José Ruiz-Shulcloper. A survey of clustering ensemble algorithms. International Journal of Pattern Recognition and Artificial Intelligence, 25(03):337-372, 2011. +[36] Huikai Wu, Shuai Zheng, Junge Zhang, and Kaiqi Huang. Gp-gan: Towards realistic high-resolution image blending. In Proceedings of the 27th ACM international conference on multimedia, pages 2487-2495, 2019. +[37] Tao Xu, Pengchuan Zhang, Qiuyuan Huang, Han Zhang, Zhe Gan, Xiaolei Huang, and Xiaodong He. Attngan: Fine-grained text to image generation with attentional generative adversarial networks. Cornell University - arXiv, 2017. +[38] Linjie Yang, Ping Luo, Chen Change Loy, and Xiaou Tang. A large-scale car dataset for fine-grained categorization and verification. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3973-3981, 2015. +[39] Pengyi Yang, Yee Hwa Yang, Bing B Zhou, and Albert Y Zomaya. A review of ensemble methods in bioinformatics. Current Bioinformatics, 5(4):296-308, 2010. +[40] Hui Ye, Xiulong Yang, Martin Takac, Rajshekhar Sunderraman, and Shihao Ji. Improving text-to-image synthesis using contrastive learning. arXiv preprint arXiv:2107.02423, 2021. +[41] Han Zhang, Jing Yu Koh, Jason Baldridge, Honglak Lee, and Yinfei Yang. Cross-modal contrastive learning for text-to-image generation. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 833-842, 2021. + +[42] Zizhao Zhang, Yuanpu Xie, and Lin Yang. Photographic text-to-image synthesis with a hierarchically-nested adversarial network. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 6199-6208, 2018. +[43] Jing Zhao, Heliang Zheng, Chaoyue Wang, Long Lan, Wanrong Huang, and Wenjing Yang. Null-text guidance in diffusion models is secretly a cartoon-style creator. arXiv preprint arXiv:2305.06710, 2023. +[44] Ying Zhao, Jun Gao, and Xuezhi Yang. A survey of neural network ensembles. In 2005 international conference on neural networks and brain, volume 1, pages 438-442. IEEE, 2005. +[45] Minfeng Zhu, Pingbo Pan, Wei Chen, and Yi Yang. Dm-gan: Dynamic memory generative adversarial networks for text-to-image synthesis. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 5802-5810, 2019. \ No newline at end of file diff --git a/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/images.zip b/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..02ef7ffec2a8d51971ce3384c0c3afc674de7076 --- /dev/null +++ b/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:28dc4fd3d0e1bde06a9261fa426a0a92b6da820b7643aabe55a6697dcf0ce900 +size 1287829 diff --git a/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/layout.json b/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..519f9497aa1975b1f539ad05384d86ba60c00089 --- /dev/null +++ b/2023/MagicFusion_ Boosting Text-to-Image Generation Performance by Fusing Diffusion Models/layout.json @@ -0,0 +1,8755 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 102, + 103, + 493, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 102, + 103, + 493, + 140 + ], + "spans": [ + { + "bbox": [ + 102, + 103, + 493, + 140 + ], + "type": "text", + "content": "MagicFusion: Boosting Text-to-Image Generation Performance by Fusing Diffusion Models" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 116, + 166, + 481, + 182 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 116, + 166, + 481, + 182 + ], + "spans": [ + { + "bbox": [ + 116, + 166, + 481, + 182 + ], + "type": "text", + "content": "Jing Zhao" + }, + { + "bbox": [ + 116, + 166, + 481, + 182 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 116, + 166, + 481, + 182 + ], + "type": "text", + "content": ", Heliang Zheng" + }, + { + "bbox": [ + 116, + 166, + 481, + 182 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 116, + 166, + 481, + 182 + ], + "type": "text", + "content": ", Chaoyue Wang" + }, + { + "bbox": [ + 116, + 166, + 481, + 182 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 116, + 166, + 481, + 182 + ], + "type": "text", + "content": ", Long Lan" + }, + { + "bbox": [ + 116, + 166, + 481, + 182 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 116, + 166, + 481, + 182 + ], + "type": "text", + "content": ", Wenjing Yang" + }, + { + "bbox": [ + 116, + 166, + 481, + 182 + ], + "type": "inline_equation", + "content": "^{1\\dagger}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 147, + 182, + 452, + 197 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 147, + 182, + 452, + 197 + ], + "spans": [ + { + "bbox": [ + 147, + 182, + 452, + 197 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 147, + 182, + 452, + 197 + ], + "type": "text", + "content": "National University of Defense Technology, Changsha, China," + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 206, + 196, + 392, + 210 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 206, + 196, + 392, + 210 + ], + "spans": [ + { + "bbox": [ + 206, + 196, + 392, + 210 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 206, + 196, + 392, + 210 + ], + "type": "text", + "content": "JD Explore Academy, Beijing, China" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 212, + 545, + 224 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 212, + 545, + 224 + ], + "spans": [ + { + "bbox": [ + 53, + 212, + 545, + 224 + ], + "type": "text", + "content": "{zhaojing,long.lan,wenjing.yang}@nudt.edu.cn,zhenghllj@gmail.com,chaoyue.wang@outlook.com" + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 48, + 250, + 202, + 470 + ], + "blocks": [ + { + "bbox": [ + 48, + 250, + 202, + 470 + ], + "lines": [ + { + "bbox": [ + 48, + 250, + 202, + 470 + ], + "spans": [ + { + "bbox": [ + 48, + 250, + 202, + 470 + ], + "type": "image", + "image_path": "c53a296ef2f0ac2479375b6f989d973ad745e0409f3bdd1aa7efe795781ff089.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 478, + 547, + 526 + ], + "lines": [ + { + "bbox": [ + 45, + 478, + 547, + 526 + ], + "spans": [ + { + "bbox": [ + 45, + 478, + 547, + 526 + ], + "type": "text", + "content": "Figure 1: \"MagicFusion\". Given two diffusion models, our method can preserve the strengths of each individual model. (a) A general model [27] + a fine-grained car model to achieve fine-grained generation with complex scenes. (b) A general model + a DreamBooth model [28] to recontextualize specific objects with well-preserved details. (c) A general model + a cartoon model to generate creative scenes with photorealistic fidelity." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 209, + 250, + 353, + 469 + ], + "blocks": [ + { + "bbox": [ + 209, + 250, + 353, + 469 + ], + "lines": [ + { + "bbox": [ + 209, + 250, + 353, + 469 + ], + "spans": [ + { + "bbox": [ + 209, + 250, + 353, + 469 + ], + "type": "image", + "image_path": "4015815acb025edfc67f3fa82bc8d01d1b7f9971da5177fda74d2f01126cc2fd.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 359, + 250, + 547, + 469 + ], + "blocks": [ + { + "bbox": [ + 359, + 250, + 547, + 469 + ], + "lines": [ + { + "bbox": [ + 359, + 250, + 547, + 469 + ], + "spans": [ + { + "bbox": [ + 359, + 250, + 547, + 469 + ], + "type": "image", + "image_path": "5e1ee9391e257e3bdb144457538a57f38401c9c775794644b5b98f50ab16a968.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 143, + 527, + 192, + 539 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 527, + 192, + 539 + ], + "spans": [ + { + "bbox": [ + 143, + 527, + 192, + 539 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 45, + 552, + 288, + 684 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 552, + 288, + 684 + ], + "spans": [ + { + "bbox": [ + 45, + 552, + 288, + 684 + ], + "type": "text", + "content": "The advent of open-source AI communities has produced a cornucopia of powerful text-guided diffusion models that are trained on various datasets. While few explorations have been conducted on ensembling such models to combine their strengths. In this work, we propose a simple yet effective method called Saliency-aware Noise Blending (SNB) that can empower the fused text-guided diffusion models to achieve more controllable generation. Specifically, we experimentally find that the responses of classifier-free guidance are highly related to the saliency of generated images. Thus we propose to trust different mod" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 528, + 547, + 635 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 528, + 547, + 635 + ], + "spans": [ + { + "bbox": [ + 306, + 528, + 547, + 635 + ], + "type": "text", + "content": "els in their areas of expertise by blending the predicted noises of two diffusion models in a saliency-aware manner. SNB is training-free and can be completed within a DDIM sampling process. Additionally, it can automatically align the semantics of two noise spaces without requiring additional annotations such as masks. Extensive experiments show the impressive effectiveness of SNB in various applications. The project page is available at https://magicfusion.github.io/." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 657, + 387, + 670 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 657, + 387, + 670 + ], + "spans": [ + { + "bbox": [ + 306, + 657, + 387, + 670 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 677, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 677, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 306, + 677, + 547, + 715 + ], + "type": "text", + "content": "In recent years, significant progress has been made in image generation [29, 6, 24, 23, 27, 20, 29, 5] thanks to breakthroughs in diffusion models [32, 29, 33] and large-" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 693, + 246, + 703 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 693, + 246, + 703 + ], + "spans": [ + { + "bbox": [ + 58, + 693, + 246, + 703 + ], + "type": "text", + "content": "*Work done during an internship at JD Explore Academy." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "type": "text", + "content": "† Corresponding authors." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "22592" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 276 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 276 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 276 + ], + "type": "text", + "content": "scale training [24, 20, 29, 5], as well as the contributions of open-source AI communities. Pre-trained large models have become an invaluable resource in this field. One of the most exciting developments has been text-guided diffusion models [24, 20, 29, 27]. A wide range of powerful text-guided diffusion models trained on various datasets has been publicly released. For example, general models (e.g., stable diffusion v1-4, v1-5, v2-1, etc. [27]) trained on large-scale multimodal datasets like LAION 5B [31], as well as more specialized models (e.g., Anything-v3) trained on cartoon and anime datasets or fine-grained categories such as cars [38]. There are even fine-tuned models designed for specific objects [28]. The vast amounts of data and computational cost have enabled these models to achieve impressive capabilities in various fields. However, few explorations have been conducted on ensembling such models to combine their strengths." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 278, + 289, + 469 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 278, + 289, + 469 + ], + "spans": [ + { + "bbox": [ + 46, + 278, + 289, + 469 + ], + "type": "text", + "content": "Some works propose to add special symbols or signature phrases when fine-tuning models on new datasets [1]. This approach enables the model to generate novel image distributions while retaining its ability to generate from the original data distribution. However, there has been limited discussion on how to effectively combine the generation capabilities of these two distributions. One intuitive method for integrating the capabilities of two models involves taking a weighted average of their predicted noises [2]. However, such kind of fusions often fails to fully preserve the strengths of each model. Blended diffusion [3] proposes to spatially blend a noisy image and a predicted one, which has been explored in image editing tasks. However, this typically requires specifying a mask to edit particular objects, and few discussions have been conducted to blend the noises of two diffusion models." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 472, + 289, + 675 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 472, + 289, + 675 + ], + "spans": [ + { + "bbox": [ + 46, + 472, + 289, + 675 + ], + "type": "text", + "content": "In this work, we propose a simple yet effective method called Saliency-aware Noise Blending (SNB) that can empower the fused text-guided diffusion models to achieve more controllable generation. Specifically, we integrate two diffusion models by spatially blending the predicted noises. Our insight is to trust different models in their areas of expertise, thus the strengths of each individual model can be preserved. To obtain diffusion models' areas of expertise, we revisit the classifier-free guidance [13], which is widely adopted in text-guided diffusion models to enhance the difference between a given text and a null text in the predicted noise space. We experimentally find that the responses of classifier-free guidance are highly related to the saliency of generated images. To this end, we propose Saliency-aware Noise Blending that blends the predicted noises of two diffusion models based on their responses to classifier-free guidance." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 677, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 288, + 715 + ], + "type": "text", + "content": "SNB is training-free and can be completed within a DDIM sampling [33] process. Additionally, it can automatically align the semantics of two noise spaces without" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 305, + 72, + 545, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 95 + ], + "type": "text", + "content": "requiring additional annotations such as masks. Our main contributions can be summarised as follows:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 317, + 96, + 545, + 239 + ], + "type": "list", + "angle": 0, + "index": 8, + "blocks": [ + { + "bbox": [ + 317, + 96, + 545, + 132 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 96, + 545, + 132 + ], + "spans": [ + { + "bbox": [ + 317, + 96, + 545, + 132 + ], + "type": "text", + "content": "- We propose to fuse two well-trained diffusion models to achieve more powerful image generation, which is a novel and valuable topic." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 317, + 133, + 545, + 179 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 133, + 545, + 179 + ], + "spans": [ + { + "bbox": [ + 317, + 133, + 545, + 179 + ], + "type": "text", + "content": "- We propose a simple yet effective Saliency-aware Noise Blending method for text-guided diffusion models fusion, which can preserve the strengths of each individual model." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 180, + 545, + 239 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 180, + 545, + 239 + ], + "spans": [ + { + "bbox": [ + 317, + 180, + 545, + 239 + ], + "type": "text", + "content": "- We conduct extensive experiments on three challenging applications (i.e., a general model + a cartoon model, a fine-grained car model, and a Dream-Booth [28] model), and prove that SNB can significantly empower pre-trained diffusion models." + } + ] + } + ], + "index": 7 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 304, + 240, + 545, + 324 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 240, + 545, + 324 + ], + "spans": [ + { + "bbox": [ + 304, + 240, + 545, + 324 + ], + "type": "text", + "content": "The remainder of the paper is organized as follows. We describe related work in Section 2 and introduce our proposed SNB method in Section 3. An evaluation of three applications is presented in Section 4, followed by the results and comparisons with other methods in Section 5. Finally, a comprehensive summary of the paper is presented and an analysis of the limitations is provided in Section 6." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 336, + 398, + 348 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 336, + 398, + 348 + ], + "spans": [ + { + "bbox": [ + 306, + 336, + 398, + 348 + ], + "type": "text", + "content": "2. Related Works" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 357, + 439, + 369 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 357, + 439, + 369 + ], + "spans": [ + { + "bbox": [ + 306, + 357, + 439, + 369 + ], + "type": "text", + "content": "2.1. Text-to-image synthesis" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 375, + 545, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 375, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 304, + 375, + 545, + 555 + ], + "type": "text", + "content": "Text-guided image generation plays a significant role in image generation [43, 16, 7, 12, 36, 15, 17, 21, 22, 24, 42]. Previous works mainly focus on GAN-based [10] models and small-scale image-text datasets [45, 34, 37, 41, 40]. Since Transformer-based autoregressive models [8, 24] were proposed, more and more attention has been attracted to large-scale training. The emergence of denoising diffusion models is another milestone, which significantly boosts the generation fidelity [23, 30, 20, 27]. Notably, Stable Diffusion [27] is publicly released, enabling a large number of variants that are fine-tuned on different datasets. The vast amounts of data and computational cost have enabled these models to achieve impressive capabilities in various fields. However, few explorations have been conducted on assembling such models to combine their strengths." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 563, + 417, + 575 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 563, + 417, + 575 + ], + "spans": [ + { + "bbox": [ + 306, + 563, + 417, + 575 + ], + "type": "text", + "content": "2.2. Model Ensembling" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 582, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 545, + 715 + ], + "type": "text", + "content": "Model ensembling is a powerful technique to distill the knowledge of multiple models and boost the performance, which is widely obtained in image understanding tasks, i.e., classification problems [44, 26, 11, 39], regression problems [19, 25] and clustering [35]. White such methods are hard to be adapted to generative models due to the large and complex image pixel space. Vision-aided GAN [14] proposes ensembling pre-trained vision models as a loss to guide the optimization of a generator. eDiff-I [4] proposes to ensemble different denoisers in different timesteps to improve the overall performance of image generation. In this" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "22593" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 76, + 545, + 277 + ], + "blocks": [ + { + "bbox": [ + 50, + 76, + 545, + 277 + ], + "lines": [ + { + "bbox": [ + 50, + 76, + 545, + 277 + ], + "spans": [ + { + "bbox": [ + 50, + 76, + 545, + 277 + ], + "type": "image", + "image_path": "4901b11e721ec37d70191db2a3f1e3d05d47a795f806d673ff60f866bb004624.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 282, + 547, + 331 + ], + "lines": [ + { + "bbox": [ + 46, + 282, + 547, + 331 + ], + "spans": [ + { + "bbox": [ + 46, + 282, + 547, + 331 + ], + "type": "text", + "content": "Figure 2: An overview of our Saliency-aware Noise Blending (SNB). Given two diffusion models, we first design a \"Noise to salience map\" module to obtain salience maps. After that, we can generate saliency-aware masks based on the salience maps. Finally, we blend the diffusion models in the noise space according to the mask. " + }, + { + "bbox": [ + 46, + 282, + 547, + 331 + ], + "type": "inline_equation", + "content": "(^{*})\\hat{\\epsilon}_{g}" + }, + { + "bbox": [ + 46, + 282, + 547, + 331 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 282, + 547, + 331 + ], + "type": "inline_equation", + "content": "\\hat{\\epsilon}_e" + }, + { + "bbox": [ + 46, + 282, + 547, + 331 + ], + "type": "text", + "content": " are noises instead of noisy images, and we add the image here just for visualization." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 352, + 288, + 389 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 352, + 288, + 389 + ], + "spans": [ + { + "bbox": [ + 46, + 352, + 288, + 389 + ], + "type": "text", + "content": "work, we propose to ensemble different pre-trained diffusion models in a novel dimension, i.e., spatial, which can be applied to various scenarios." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 399, + 105, + 411 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 399, + 105, + 411 + ], + "spans": [ + { + "bbox": [ + 47, + 399, + 105, + 411 + ], + "type": "text", + "content": "3. Method" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 418, + 287, + 528 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 418, + 287, + 528 + ], + "spans": [ + { + "bbox": [ + 46, + 418, + 287, + 528 + ], + "type": "text", + "content": "In this section, we introduce our proposed saliency-aware noise blending. Specifically, we first review the widely obtained classifier-free guidance, after that, we revisit such guidance and experimentally find that the classifier-free guidance is secretly a saliency indicator. Based on the salience map, we can obtain a saliency-aware mask, which is further used to guide the blending of the noise of two diffusion models. Figure 2 show the whole pipeline, and more details can be found in the following." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 533, + 133, + 545 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 533, + 133, + 545 + ], + "spans": [ + { + "bbox": [ + 47, + 533, + 133, + 545 + ], + "type": "text", + "content": "3.1. Preliminaries" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "spans": [ + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "text", + "content": "Given a pre-trained text-guided diffusion model, we can generate images by a DDPM/DDIM sampling process, which progressively converts a Gaussian noise into an image for " + }, + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "text", + "content": " timesteps. Take the DDIM sampling for example, a denoising step can be denoted as:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 59, + 619, + 287, + 647 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 619, + 287, + 647 + ], + "spans": [ + { + "bbox": [ + 59, + 619, + 287, + 647 + ], + "type": "interline_equation", + "content": "x _ {t - 1} = \\sqrt {\\bar {\\alpha} _ {t - 1}} \\left(\\frac {x _ {t} - \\sqrt {1 - \\bar {\\alpha} _ {t}} \\hat {\\epsilon}}{\\sqrt {\\bar {\\alpha} _ {t}}}\\right) + \\sqrt {1 - \\bar {\\alpha} _ {t - 1}} \\hat {\\epsilon}, \\tag {1}", + "image_path": "ef3aa363e11fc538ce06b82c7e2f92cfdbf206c93b345b23faad6210522e248e.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "content": " indicates the timestep, " + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "content": " is the noisy image, " + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\bar{\\alpha}" + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "content": " is related to a pre-defined variance schedule, and " + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\hat{\\epsilon}" + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "content": " is the predicted noise. The predicted noise can be re-modulated by classifier-free guidance [13], which is designed to extrapolate the output of the model in the direction of " + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\epsilon_{\\theta}(x_t|c)" + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "content": " and" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 352, + 436, + 365 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 352, + 436, + 365 + ], + "spans": [ + { + "bbox": [ + 305, + 352, + 436, + 365 + ], + "type": "text", + "content": "away from " + }, + { + "bbox": [ + 305, + 352, + 436, + 365 + ], + "type": "inline_equation", + "content": "\\epsilon_{\\theta}(x_t|\\varnothing)" + }, + { + "bbox": [ + 305, + 352, + 436, + 365 + ], + "type": "text", + "content": " as follows:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 339, + 369, + 545, + 383 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 339, + 369, + 545, + 383 + ], + "spans": [ + { + "bbox": [ + 339, + 369, + 545, + 383 + ], + "type": "interline_equation", + "content": "\\hat {\\epsilon} = \\epsilon_ {\\theta} \\left(x _ {t} | \\varnothing\\right) + s \\cdot \\left(\\epsilon_ {\\theta} \\left(x _ {t} \\mid c\\right) - \\epsilon_ {\\theta} \\left(x _ {t} | \\varnothing\\right)\\right), \\tag {2}", + "image_path": "72883d573a475cece3e7cdc2b7af81d7ec2d38003d1d4583a1e7072bb0076d80.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "spans": [ + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "type": "inline_equation", + "content": "\\epsilon_{\\theta}" + }, + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "type": "text", + "content": " is the pretrained model, " + }, + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "type": "inline_equation", + "content": "c" + }, + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "type": "text", + "content": " is the text condition, " + }, + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "type": "inline_equation", + "content": "\\varnothing" + }, + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "type": "text", + "content": " is a null text, " + }, + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "type": "text", + "content": " is the guidance weight and increasing " + }, + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "type": "inline_equation", + "content": "s > 1" + }, + { + "bbox": [ + 305, + 387, + 546, + 422 + ], + "type": "text", + "content": " strengthens the effect of guidance." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 428, + 432, + 441 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 428, + 432, + 441 + ], + "spans": [ + { + "bbox": [ + 306, + 428, + 432, + 441 + ], + "type": "text", + "content": "3.2. Noise to Salience Map" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 447, + 545, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 447, + 545, + 568 + ], + "spans": [ + { + "bbox": [ + 304, + 447, + 545, + 568 + ], + "type": "text", + "content": "We experimentally find that the classifier-free guidance introduced above is secretly a saliency indicator. Specifically, " + }, + { + "bbox": [ + 304, + 447, + 545, + 568 + ], + "type": "inline_equation", + "content": "\\epsilon_{\\theta}(x_t|c) - \\epsilon_{\\theta}(x_t|\\varnothing)" + }, + { + "bbox": [ + 304, + 447, + 545, + 568 + ], + "type": "text", + "content": " in Eqn. 2 indicates the difference between a conditional prediction and an unconditional prediction, thus the objects and scenes appeared in the text condition would be emphasized with a large value, especially when we adopt a large guidance scale " + }, + { + "bbox": [ + 304, + 447, + 545, + 568 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 304, + 447, + 545, + 568 + ], + "type": "text", + "content": " (e.g., 10-100). We visualize the re-modulated noises of Eqn. 2 and find that the important region does have high responses. To this end, we propose to obtain a salience map by the following operation:" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 339, + 578, + 545, + 591 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 339, + 578, + 545, + 591 + ], + "spans": [ + { + "bbox": [ + 339, + 578, + 545, + 591 + ], + "type": "interline_equation", + "content": "\\Lambda \\left(\\epsilon_ {t}\\right) = \\operatorname {B l u r} \\left(\\operatorname {A b s} \\left(\\epsilon_ {\\theta} \\left(x _ {t} \\mid c\\right) - \\epsilon_ {\\theta} \\left(x _ {t} \\mid \\varnothing\\right)\\right)\\right) \\tag {3}", + "image_path": "9d2df2637483b7a5f95498a82f8385e9315088f88a3e59762b074b963bcceaec.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 594, + 547, + 654 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 547, + 654 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 547, + 654 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 594, + 547, + 654 + ], + "type": "inline_equation", + "content": "\\Lambda (\\epsilon_t)" + }, + { + "bbox": [ + 304, + 594, + 547, + 654 + ], + "type": "text", + "content": " represents the salience map, " + }, + { + "bbox": [ + 304, + 594, + 547, + 654 + ], + "type": "inline_equation", + "content": "Abs(\\cdot)" + }, + { + "bbox": [ + 304, + 594, + 547, + 654 + ], + "type": "text", + "content": " calculates the absolute value of the input variables, and " + }, + { + "bbox": [ + 304, + 594, + 547, + 654 + ], + "type": "inline_equation", + "content": "Blur(\\cdot)" + }, + { + "bbox": [ + 304, + 594, + 547, + 654 + ], + "type": "text", + "content": " is used to smooth the high-frequency noise, which can eliminate local interference responses and leverage the coherence of adjacent regions." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 659, + 444, + 672 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 659, + 444, + 672 + ], + "spans": [ + { + "bbox": [ + 306, + 659, + 444, + 672 + ], + "type": "text", + "content": "3.3. Saliency-aware Blending" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 305, + 677, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 714 + ], + "type": "text", + "content": "The above discussions are all about a single diffusion model, and now let us move to the next stage, i.e., obtaining a blending mask based on two models' salience maps." + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "22594" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 120 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 120 + ], + "type": "text", + "content": "Given a general model and an expert model, we can obtain the corresponding salience maps by Eqn. 3, which are denoted as " + }, + { + "bbox": [ + 47, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "\\Lambda^g" + }, + { + "bbox": [ + 47, + 72, + 287, + 120 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "\\Lambda^e" + }, + { + "bbox": [ + 47, + 72, + 287, + 120 + ], + "type": "text", + "content": ", respectively. We first normalize these salience maps by the softmax function:" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 111, + 129, + 286, + 150 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 129, + 286, + 150 + ], + "spans": [ + { + "bbox": [ + 111, + 129, + 286, + 150 + ], + "type": "interline_equation", + "content": "\\Lambda^ {g ^ {\\prime}} = \\operatorname {s o f t m a x} (k ^ {g} * \\Lambda^ {g}) \\tag {4}", + "image_path": "30c36f3c4f82c4d24daa2ed8961d36943302940c45e2031ac914a19f2aac6b43.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 113, + 148, + 222, + 162 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 113, + 148, + 222, + 162 + ], + "spans": [ + { + "bbox": [ + 113, + 148, + 222, + 162 + ], + "type": "interline_equation", + "content": "\\Lambda^ {e ^ {\\prime}} = \\operatorname {s o f t m a x} \\left(k ^ {e} * \\Lambda^ {e}\\right),", + "image_path": "fc929944bbb063797b8d9e80aa8dc48b64eb2ba7cee209503a6e41aeb002a8d3.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 171, + 288, + 291 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 171, + 288, + 291 + ], + "spans": [ + { + "bbox": [ + 47, + 171, + 288, + 291 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 171, + 288, + 291 + ], + "type": "inline_equation", + "content": "k^g" + }, + { + "bbox": [ + 47, + 171, + 288, + 291 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 171, + 288, + 291 + ], + "type": "inline_equation", + "content": "k^e" + }, + { + "bbox": [ + 47, + 171, + 288, + 291 + ], + "type": "text", + "content": " are hyper-parameters, i.e., temperature of the softmax. Note that the softmax here ensures the sum of each salience map to be a constant (i.e., 1), which means each model must focus on some regions instead of having a high response everywhere. When we integrate a general model and an expert model, the salience map of the general model tends to cover multiple objects to compose the whole scene, while the expert model tends to have a higher response to a specific object. Thus we obtain a blending mask " + }, + { + "bbox": [ + 47, + 171, + 288, + 291 + ], + "type": "inline_equation", + "content": "\\mathcal{M}" + }, + { + "bbox": [ + 47, + 171, + 288, + 291 + ], + "type": "text", + "content": " by comparing these two salience maps:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 116, + 300, + 287, + 316 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 116, + 300, + 287, + 316 + ], + "spans": [ + { + "bbox": [ + 116, + 300, + 287, + 316 + ], + "type": "interline_equation", + "content": "\\mathcal {M} = \\arg \\max \\left(\\Lambda^ {g ^ {\\prime}}, \\Lambda^ {e ^ {\\prime}}\\right) \\tag {5}", + "image_path": "456a87d9b201b31d96c082d4c35a2d22cca3d637eaf7e490fe70250d4bb68f6a.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 323, + 287, + 369 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 323, + 287, + 369 + ], + "spans": [ + { + "bbox": [ + 47, + 323, + 287, + 369 + ], + "type": "text", + "content": "The saliency-aware mask is an effective guide to perform noise blending, which consists of binary values of 0 and 1, corresponding to the noise " + }, + { + "bbox": [ + 47, + 323, + 287, + 369 + ], + "type": "inline_equation", + "content": "\\epsilon_{g}" + }, + { + "bbox": [ + 47, + 323, + 287, + 369 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 323, + 287, + 369 + ], + "type": "inline_equation", + "content": "\\epsilon_{e}" + }, + { + "bbox": [ + 47, + 323, + 287, + 369 + ], + "type": "text", + "content": " respectively. We can obtain the fused noise as follows:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 104, + 384, + 287, + 396 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 104, + 384, + 287, + 396 + ], + "spans": [ + { + "bbox": [ + 104, + 384, + 287, + 396 + ], + "type": "interline_equation", + "content": "\\hat {\\epsilon} = \\mathcal {M} \\odot \\hat {\\epsilon} _ {g} + (1 - \\mathcal {M}) \\odot \\hat {\\epsilon} _ {e}, \\tag {6}", + "image_path": "d105b4df64e4413a77ff9319adafc005ea29bea40149ad0b9b9ff2bb0082a637.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 402, + 287, + 485 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 402, + 287, + 485 + ], + "spans": [ + { + "bbox": [ + 47, + 402, + 287, + 485 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 402, + 287, + 485 + ], + "type": "inline_equation", + "content": "\\odot" + }, + { + "bbox": [ + 47, + 402, + 287, + 485 + ], + "type": "text", + "content": " denotes Hadamard (element-wise) Product, and we omit " + }, + { + "bbox": [ + 47, + 402, + 287, + 485 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 47, + 402, + 287, + 485 + ], + "type": "text", + "content": " for simplicity. In the specific implementation process, the fusion strategy is executed only when " + }, + { + "bbox": [ + 47, + 402, + 287, + 485 + ], + "type": "inline_equation", + "content": "t \\leq t_s" + }, + { + "bbox": [ + 47, + 402, + 287, + 485 + ], + "type": "text", + "content": ", ensuring that the fusion results possess the fundamental structure of images generated by the general model. Algorithm 1 summarizes the process of the saliency-aware noise blending algorithm." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 487, + 287, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 487, + 287, + 605 + ], + "spans": [ + { + "bbox": [ + 47, + 487, + 287, + 605 + ], + "type": "text", + "content": "Additional explanations on the three applications. In the three applications (i.e., a general model + a fine-grained model, a DreamBooth model, and a cartoon model) of this work, the expert model of the former two focuses on a specific object, while the last one contributes to the global structure of the generated image. In the last application, the cartoon model tends to focus on low-frequency structure and the general model focuses on high-frequency details. Thus the blended mask is not object-level, and we remove the blur operation in Eqn. 3 to facilitate such blending." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 605, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 605, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 605, + 287, + 713 + ], + "type": "text", + "content": "Clarification of technique novelty. The overall process of this algorithm is quite simple, yet it is non-trivial by solving two challenges. Firstly, we leverage the classifier-free guidance to automatically identify each model's areas of expertise. The introduction of the hyper-parameter " + }, + { + "bbox": [ + 47, + 605, + 287, + 713 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 47, + 605, + 287, + 713 + ], + "type": "text", + "content": " provides improved controllability for blending the two sources of images, thereby enabling greater creativity and flexibility in image generation based on SNB. Secondly, the task of obtaining saliency response values that are closely linked" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 72, + 489, + 84 + ], + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 489, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 489, + 84 + ], + "type": "text", + "content": "Algorithm 1 Saliency-aware Noise Blending" + } + ] + } + ], + "index": 10, + "type": "text" + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "spans": [ + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "text", + "content": "Input: Two pre-trained models " + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "inline_equation", + "content": "\\epsilon_{\\theta_g}" + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "inline_equation", + "content": "\\epsilon_{\\theta_e}" + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "text", + "content": ", along with two prompts, " + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "inline_equation", + "content": "y_{g}" + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "inline_equation", + "content": "y_{e}" + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "text", + "content": ". gradient scale " + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "text", + "content": " in Eq.(2). Hyperparameters " + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "inline_equation", + "content": "k^a" + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "inline_equation", + "content": "k^b" + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "text", + "content": " in Eq. (4) and fusion time " + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "inline_equation", + "content": "t_s" + }, + { + "bbox": [ + 306, + 87, + 545, + 123 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 124, + 427, + 135 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 124, + 427, + 135 + ], + "spans": [ + { + "bbox": [ + 306, + 124, + 427, + 135 + ], + "type": "text", + "content": "Output: The fused image " + }, + { + "bbox": [ + 306, + 124, + 427, + 135 + ], + "type": "inline_equation", + "content": "x_0" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 309, + 136, + 545, + 330 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 312, + 136, + 383, + 147 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 136, + 383, + 147 + ], + "spans": [ + { + "bbox": [ + 312, + 136, + 383, + 147 + ], + "type": "text", + "content": "1: " + }, + { + "bbox": [ + 312, + 136, + 383, + 147 + ], + "type": "inline_equation", + "content": "x_{T}\\sim \\mathcal{N}(0,I)" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 312, + 148, + 410, + 158 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 148, + 410, + 158 + ], + "spans": [ + { + "bbox": [ + 312, + 148, + 410, + 158 + ], + "type": "text", + "content": "2: for " + }, + { + "bbox": [ + 312, + 148, + 410, + 158 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 312, + 148, + 410, + 158 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 312, + 148, + 410, + 158 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 312, + 148, + 410, + 158 + ], + "type": "text", + "content": " to 0 do" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 312, + 159, + 391, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 159, + 391, + 171 + ], + "spans": [ + { + "bbox": [ + 312, + 159, + 391, + 171 + ], + "type": "text", + "content": "3: if " + }, + { + "bbox": [ + 312, + 159, + 391, + 171 + ], + "type": "inline_equation", + "content": "t > t_{s}" + }, + { + "bbox": [ + 312, + 159, + 391, + 171 + ], + "type": "text", + "content": " then" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 312, + 173, + 377, + 184 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 173, + 377, + 184 + ], + "spans": [ + { + "bbox": [ + 312, + 173, + 377, + 184 + ], + "type": "text", + "content": "4: " + }, + { + "bbox": [ + 312, + 173, + 377, + 184 + ], + "type": "inline_equation", + "content": "\\epsilon_{t} = \\epsilon_{t_{g}}" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 312, + 185, + 352, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 185, + 352, + 193 + ], + "spans": [ + { + "bbox": [ + 312, + 185, + 352, + 193 + ], + "type": "text", + "content": "5: else" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 312, + 194, + 479, + 207 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 194, + 479, + 207 + ], + "spans": [ + { + "bbox": [ + 312, + 194, + 479, + 207 + ], + "type": "text", + "content": "6: " + }, + { + "bbox": [ + 312, + 194, + 479, + 207 + ], + "type": "inline_equation", + "content": "\\epsilon_{t_q} = \\epsilon_{\\theta_q}(x_t|c_g),\\epsilon_{t_e} = \\epsilon_{\\theta_e}(x_t|c_e)" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 312, + 208, + 523, + 220 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 208, + 523, + 220 + ], + "spans": [ + { + "bbox": [ + 312, + 208, + 523, + 220 + ], + "type": "text", + "content": "7: get " + }, + { + "bbox": [ + 312, + 208, + 523, + 220 + ], + "type": "inline_equation", + "content": "\\Lambda^g (\\epsilon_{t_g})" + }, + { + "bbox": [ + 312, + 208, + 523, + 220 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 312, + 208, + 523, + 220 + ], + "type": "inline_equation", + "content": "\\Lambda^{e}(\\epsilon_{t_{e}})" + }, + { + "bbox": [ + 312, + 208, + 523, + 220 + ], + "type": "text", + "content": " according to Eq.(3)." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 312, + 220, + 494, + 234 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 220, + 494, + 234 + ], + "spans": [ + { + "bbox": [ + 312, + 220, + 494, + 234 + ], + "type": "text", + "content": "8: get " + }, + { + "bbox": [ + 312, + 220, + 494, + 234 + ], + "type": "inline_equation", + "content": "\\Lambda^{g'}(\\epsilon_{t_g})" + }, + { + "bbox": [ + 312, + 220, + 494, + 234 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 312, + 220, + 494, + 234 + ], + "type": "inline_equation", + "content": "\\Lambda^{e'}(\\epsilon_{t_e})" + }, + { + "bbox": [ + 312, + 220, + 494, + 234 + ], + "type": "text", + "content": " via Eq. (4)." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 312, + 235, + 444, + 247 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 235, + 444, + 247 + ], + "spans": [ + { + "bbox": [ + 312, + 235, + 444, + 247 + ], + "type": "text", + "content": "9: " + }, + { + "bbox": [ + 312, + 235, + 444, + 247 + ], + "type": "inline_equation", + "content": "\\mathcal{M} = \\arg \\max (\\Lambda^{a'},\\Lambda^{b'})" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 312, + 247, + 545, + 270 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 247, + 545, + 270 + ], + "spans": [ + { + "bbox": [ + 312, + 247, + 545, + 270 + ], + "type": "text", + "content": "10: get the noise generated by classifier-free guidance " + }, + { + "bbox": [ + 312, + 247, + 545, + 270 + ], + "type": "inline_equation", + "content": "\\hat{\\epsilon}_{t_g}" + }, + { + "bbox": [ + 312, + 247, + 545, + 270 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 312, + 247, + 545, + 270 + ], + "type": "inline_equation", + "content": "\\hat{\\epsilon}_{t_e}" + }, + { + "bbox": [ + 312, + 247, + 545, + 270 + ], + "type": "text", + "content": " via Eq.(2)." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 309, + 271, + 474, + 283 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 271, + 474, + 283 + ], + "spans": [ + { + "bbox": [ + 309, + 271, + 474, + 283 + ], + "type": "text", + "content": "11: " + }, + { + "bbox": [ + 309, + 271, + 474, + 283 + ], + "type": "inline_equation", + "content": "\\epsilon_{t} = \\mathcal{M}\\odot \\hat{\\epsilon}_{t_{g}} + (1 - \\mathcal{M})\\odot \\hat{\\epsilon}_{t_{e}}" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 310, + 284, + 361, + 293 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 284, + 361, + 293 + ], + "spans": [ + { + "bbox": [ + 310, + 284, + 361, + 293 + ], + "type": "text", + "content": "12: end if" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 310, + 295, + 421, + 306 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 295, + 421, + 306 + ], + "spans": [ + { + "bbox": [ + 310, + 295, + 421, + 306 + ], + "type": "text", + "content": "13: " + }, + { + "bbox": [ + 310, + 295, + 421, + 306 + ], + "type": "inline_equation", + "content": "x_{t - 1}\\gets \\epsilon_t" + }, + { + "bbox": [ + 310, + 295, + 421, + 306 + ], + "type": "text", + "content": " via Eq.(1)" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 310, + 308, + 356, + 316 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 308, + 356, + 316 + ], + "spans": [ + { + "bbox": [ + 310, + 308, + 356, + 316 + ], + "type": "text", + "content": "14: end for" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 310, + 319, + 370, + 330 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 319, + 370, + 330 + ], + "spans": [ + { + "bbox": [ + 310, + 319, + 370, + 330 + ], + "type": "text", + "content": "15: return " + }, + { + "bbox": [ + 310, + 319, + 370, + 330 + ], + "type": "inline_equation", + "content": "x_0" + }, + { + "bbox": [ + 310, + 319, + 370, + 330 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 304, + 354, + 545, + 426 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 354, + 545, + 426 + ], + "spans": [ + { + "bbox": [ + 304, + 354, + 545, + 426 + ], + "type": "text", + "content": "to prompt content is highly non-trivial. Secondly, in each sampling step, the two models take as input the blended " + }, + { + "bbox": [ + 304, + 354, + 545, + 426 + ], + "type": "inline_equation", + "content": "x_{t}" + }, + { + "bbox": [ + 304, + 354, + 545, + 426 + ], + "type": "text", + "content": ", enabling automatic semantic alignment of the two models' noise space. We believe our exploration would contribute to the community and benefit the leveraging of pre-trained diffusion models." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 306, + 438, + 385, + 452 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 438, + 385, + 452 + ], + "spans": [ + { + "bbox": [ + 306, + 438, + 385, + 452 + ], + "type": "text", + "content": "4. Applications" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 304, + 459, + 545, + 626 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 459, + 545, + 626 + ], + "spans": [ + { + "bbox": [ + 304, + 459, + 545, + 626 + ], + "type": "text", + "content": "In order to evaluate the effectiveness of our proposed method, we conduct experiments on three challenging applications. 1) Fine-grained Fusion, i.e., fusing a general and a fine-grained model to achieve fine-grained generation with complex scenes. 2) Recontextualization, i.e., fusing a general and a DreamBooth [28] model allows for the recontextualization of specific objects with well-preserved details. 3) Cross-domain Fusion, i.e., fusing a general and a cartoon model to combine the creative advantages of the cartoon model to generate complex scenes and the photorealistic fidelity of the general model. These experiments will allow us to evaluate the performance of our method across a range of scenarios and provide valuable insights into the strengths and limitations of our approach." + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 305, + 634, + 493, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 634, + 493, + 647 + ], + "spans": [ + { + "bbox": [ + 305, + 634, + 493, + 647 + ], + "type": "text", + "content": "4.1. Application 1: Fine-grained Fusion" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "The stable diffusion model [27] trained on large-scale multimodal datasets like LAION 5B [31] has shown impressive performance on general text-to-image synthesis. In our experiments, we use the publicly released stable diffusion v1-4. Meanwhile, fine-grained car models trained on (an" + } + ] + } + ], + "index": 33 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "22595" + } + ] + } + ], + "index": 34 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 71, + 545, + 365 + ], + "blocks": [ + { + "bbox": [ + 50, + 71, + 545, + 365 + ], + "lines": [ + { + "bbox": [ + 50, + 71, + 545, + 365 + ], + "spans": [ + { + "bbox": [ + 50, + 71, + 545, + 365 + ], + "type": "image", + "image_path": "937320c0d3cdb1c35ca2a49f8f451d29728488b2ea6e569a57a8c9642b862dd1.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 369, + 546, + 394 + ], + "lines": [ + { + "bbox": [ + 46, + 369, + 546, + 394 + ], + "spans": [ + { + "bbox": [ + 46, + 369, + 546, + 394 + ], + "type": "text", + "content": "Figure 3: Application 1: visualization results of Fine-grained Fusion. Our method enables fine-grained generation with complex scenes." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 415, + 287, + 450 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 415, + 287, + 450 + ], + "spans": [ + { + "bbox": [ + 46, + 415, + 287, + 450 + ], + "type": "text", + "content": "extension of) CompCars [38] can generate fine-grained car images with specific colors, viewpoints, types, brands, and models." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 453, + 288, + 646 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 453, + 288, + 646 + ], + "spans": [ + { + "bbox": [ + 46, + 453, + 288, + 646 + ], + "type": "text", + "content": "For instance, a scene description like \"a photo of a red car in a snowy forest\" can be fed into the general model, resulting in a corresponding image as shown in the first left column of Figure 3. Similarly, a specific car description like \"red hatchback Audi (imported) Audi A1 2010 e-tron\" can be fed into the car model, generating an Audi car that matches the prompt. To fuse the noise of the two models during the denoising sampling process, we propose the SNB method, which can produce a fused image of a red Audi hatchback car in a snowy forest. The fusion results of the general model and the fine-grained car model are illustrated in Figure 3, showing the ability to replace the car in the scene with a specific one while retaining the original scene unchanged. Notably, our SNB does not require additional annotations to specify the car's position in the original image, enabling automatic semantic alignment." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 657, + 234, + 671 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 657, + 234, + 671 + ], + "spans": [ + { + "bbox": [ + 47, + 657, + 234, + 671 + ], + "type": "text", + "content": "4.2. Application 2: Recontextualization" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 677, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 287, + 714 + ], + "type": "text", + "content": "Recontextualization, or named personalizing text-to-image generation, is proposed in previous works [9, 28], which aims to generate a creative scene for a specific ob" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 415, + 545, + 487 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 415, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 304, + 415, + 545, + 487 + ], + "type": "text", + "content": "ject/concept. DreamBooth [28] proposes to fine-tune a diffusion model on several given images together with a placeholder word to enable the model to generate a specific object/concept. In this application, we integrate a general and a DreamBooth [28] model to allow for the recontextualization of specific objects with well-preserved details." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 488, + 546, + 597 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 488, + 546, + 597 + ], + "spans": [ + { + "bbox": [ + 304, + 488, + 546, + 597 + ], + "type": "text", + "content": "Specifically, we first fine-tune the general model using multiple images of the target object. Thus the fine-tuned model can represent the specific object with the placeholder \"[ ]\" in the prompt. Next, we get through a sentence that describes a complex scene and \"a photo of a [ ] < class >\" into SNB to integrate the general model and the Dream-Booth model. Results can be found in Figure 4. It can be observed that our method can put a specific object with rich details into a complex scene." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 609, + 499, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 609, + 499, + 623 + ], + "spans": [ + { + "bbox": [ + 305, + 609, + 499, + 623 + ], + "type": "text", + "content": "4.3. Application 3: Cross-domain Fusion" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 629, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 545, + 715 + ], + "type": "text", + "content": "Different models have distinct advantages when it comes to generating images with specific styles. For example, cartoon models are particularly skilled at creative composition and can generate scenes that are rarely observed in real-world scenarios. When we strive to generate images with unique and imaginative compositions, we can integrate a cartoon model to generate a distinctive scene and a general" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "22596" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 71, + 121, + 152 + ], + "blocks": [ + { + "bbox": [ + 51, + 71, + 121, + 152 + ], + "lines": [ + { + "bbox": [ + 51, + 71, + 121, + 152 + ], + "spans": [ + { + "bbox": [ + 51, + 71, + 121, + 152 + ], + "type": "image", + "image_path": "6d5663e63b0bb0ef7dce7909f563feb1179132e938474ae411e2b8de8d6738ef.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 127, + 72, + 263, + 150 + ], + "blocks": [ + { + "bbox": [ + 127, + 72, + 263, + 150 + ], + "lines": [ + { + "bbox": [ + 127, + 72, + 263, + 150 + ], + "spans": [ + { + "bbox": [ + 127, + 72, + 263, + 150 + ], + "type": "image", + "image_path": "3fe875f2c4c09105dfb6af345ec447f3e2f6fb7b54a526f1ced8f96496f8dcc5.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 128, + 158, + 264, + 166 + ], + "lines": [ + { + "bbox": [ + 128, + 158, + 264, + 166 + ], + "spans": [ + { + "bbox": [ + 128, + 158, + 264, + 166 + ], + "type": "text", + "content": "[ ] on a rock with snow mountain in the background." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 268, + 72, + 403, + 149 + ], + "blocks": [ + { + "bbox": [ + 268, + 72, + 403, + 149 + ], + "lines": [ + { + "bbox": [ + 268, + 72, + 403, + 149 + ], + "spans": [ + { + "bbox": [ + 268, + 72, + 403, + 149 + ], + "type": "image", + "image_path": "4a13bb59ebb65187504b8c7a648e8172e9fe90be8e909bb89ed50696eeb80ce5.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 408, + 72, + 543, + 149 + ], + "blocks": [ + { + "bbox": [ + 408, + 72, + 543, + 149 + ], + "lines": [ + { + "bbox": [ + 408, + 72, + 543, + 149 + ], + "spans": [ + { + "bbox": [ + 408, + 72, + 543, + 149 + ], + "type": "image", + "image_path": "45b7ac88bda42a346c6adec4f1179715b1976a88e4a5ddfa3fc7a4afa5dff9d4.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 51, + 158, + 120, + 237 + ], + "blocks": [ + { + "bbox": [ + 51, + 158, + 120, + 237 + ], + "lines": [ + { + "bbox": [ + 51, + 158, + 120, + 237 + ], + "spans": [ + { + "bbox": [ + 51, + 158, + 120, + 237 + ], + "type": "image", + "image_path": "c71c22d7f9458505e133dfb564f0c5cf05987c3f6fad3e94a7e064f9af3873b2.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 128, + 169, + 263, + 237 + ], + "blocks": [ + { + "bbox": [ + 128, + 169, + 263, + 237 + ], + "lines": [ + { + "bbox": [ + 128, + 169, + 263, + 237 + ], + "spans": [ + { + "bbox": [ + 128, + 169, + 263, + 237 + ], + "type": "image", + "image_path": "6801c958173bf18ccf56787924811b40b3d72c0cd2cc27cd0d45048ef1d1a539.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 268, + 158, + 403, + 237 + ], + "blocks": [ + { + "bbox": [ + 268, + 158, + 403, + 237 + ], + "lines": [ + { + "bbox": [ + 268, + 158, + 403, + 237 + ], + "spans": [ + { + "bbox": [ + 268, + 158, + 403, + 237 + ], + "type": "image", + "image_path": "d407e9c57a1a1c9095c780b0804526436a5ceee96559329458cca4f8efbb06ee.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 408, + 158, + 543, + 237 + ], + "blocks": [ + { + "bbox": [ + 408, + 158, + 543, + 237 + ], + "lines": [ + { + "bbox": [ + 408, + 158, + 543, + 237 + ], + "spans": [ + { + "bbox": [ + 408, + 158, + 543, + 237 + ], + "type": "image", + "image_path": "deb8230afd6a20a9f1ad36dada99a65bd123866ccaba6b615427a2a3e2c19138.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 51, + 247, + 122, + 324 + ], + "blocks": [ + { + "bbox": [ + 51, + 247, + 122, + 324 + ], + "lines": [ + { + "bbox": [ + 51, + 247, + 122, + 324 + ], + "spans": [ + { + "bbox": [ + 51, + 247, + 122, + 324 + ], + "type": "image", + "image_path": "71df950b17e0627e13ff035d8262d89f858a78b290bec10ef0ceda65ddac58e0.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 327, + 546, + 352 + ], + "lines": [ + { + "bbox": [ + 46, + 327, + 546, + 352 + ], + "spans": [ + { + "bbox": [ + 46, + 327, + 546, + 352 + ], + "type": "text", + "content": "Figure 4: Application 2: visualization results of Recontextualization. Our method can recontextualize specific objects in complex scenes with well-preserved details." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 128, + 245, + 263, + 323 + ], + "blocks": [ + { + "bbox": [ + 128, + 245, + 263, + 323 + ], + "lines": [ + { + "bbox": [ + 128, + 245, + 263, + 323 + ], + "spans": [ + { + "bbox": [ + 128, + 245, + 263, + 323 + ], + "type": "image", + "image_path": "d8b30b64a3a857632cc673cb51f7427ffa2012c80958ecf25cd94d4525d4fc71.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 268, + 245, + 403, + 323 + ], + "blocks": [ + { + "bbox": [ + 268, + 245, + 403, + 323 + ], + "lines": [ + { + "bbox": [ + 268, + 245, + 403, + 323 + ], + "spans": [ + { + "bbox": [ + 268, + 245, + 403, + 323 + ], + "type": "image", + "image_path": "548757c867aaadd4b4b46ab6481f07a745e855ddd38473cdbd288106aaeeacc3.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 408, + 245, + 542, + 323 + ], + "blocks": [ + { + "bbox": [ + 408, + 245, + 542, + 323 + ], + "lines": [ + { + "bbox": [ + 408, + 245, + 542, + 323 + ], + "spans": [ + { + "bbox": [ + 408, + 245, + 542, + 323 + ], + "type": "image", + "image_path": "868be75c33ed82c789b69b490e3012336ada6357c27e4796dd39d0a837e9975c.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 52, + 365, + 545, + 511 + ], + "blocks": [ + { + "bbox": [ + 52, + 365, + 545, + 511 + ], + "lines": [ + { + "bbox": [ + 52, + 365, + 545, + 511 + ], + "spans": [ + { + "bbox": [ + 52, + 365, + 545, + 511 + ], + "type": "image", + "image_path": "956420edf4cd12814549833214ed1303273b823ddcb130ac5c3a91f9cebe68a9.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 517, + 547, + 543 + ], + "lines": [ + { + "bbox": [ + 46, + 517, + 547, + 543 + ], + "spans": [ + { + "bbox": [ + 46, + 517, + 547, + 543 + ], + "type": "text", + "content": "Figure 5: Application 3: visualization results of Cross-domain Fusion. Our method can combine the creative advantages of the cartoon model to generate complex scenes and the photorealistic fidelity of the general model." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "bbox": [ + 47, + 563, + 216, + 574 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 563, + 216, + 574 + ], + "spans": [ + { + "bbox": [ + 47, + 563, + 216, + 574 + ], + "type": "text", + "content": "model to make the content more realistic." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": "In this application, the same textual description of a scene is fed into both the general and the cartoon models. This allows us to generate two sets of noise that correspond to the same content but different styles during the sampling process. By fusing these two sets of noise, SNB generates images that exhibit both a creative composition and realistic content. As shown in Figure 5, our proposed SNB provides a powerful tool for achieving the balance of creative and realistic, and we believe that such a tool has the potential to benefit a wide range of applications in various fields, such as art and AI-aided design." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 562, + 452, + 576 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 562, + 452, + 576 + ], + "spans": [ + { + "bbox": [ + 306, + 562, + 452, + 576 + ], + "type": "text", + "content": "5. Results and Comparisons" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 306, + 584, + 481, + 597 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 584, + 481, + 597 + ], + "spans": [ + { + "bbox": [ + 306, + 584, + 481, + 597 + ], + "type": "text", + "content": "5.1. Compared to the General Model" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "type": "text", + "content": "The stable diffusion model is a widely used and versatile generative model in computer vision that can generate a diverse range of images based on prompts. However, when the prompts contain multiple content subjects, the general model's generation performance can become challenging, especially when the combination of these subjects is rare in real-world scenes. This limitation can result in missing subjects in the generated images, as observed in Application 1, where the general model fails to capture both the car and" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "22597" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 73, + 545, + 216 + ], + "blocks": [ + { + "bbox": [ + 51, + 73, + 545, + 216 + ], + "lines": [ + { + "bbox": [ + 51, + 73, + 545, + 216 + ], + "spans": [ + { + "bbox": [ + 51, + 73, + 545, + 216 + ], + "type": "image", + "image_path": "71060445afd3f71a4bf54c6bd4631a7adc56eb14aa6e71bd7e79b00f927803de.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 220, + 546, + 246 + ], + "lines": [ + { + "bbox": [ + 46, + 220, + 546, + 246 + ], + "spans": [ + { + "bbox": [ + 46, + 220, + 546, + 246 + ], + "type": "text", + "content": "Figure 6: Compared to the general model. The general model fails to precisely generate fine-grained objects and tends to miss some objects when the prompt is full of details." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 50, + 256, + 545, + 401 + ], + "blocks": [ + { + "bbox": [ + 50, + 256, + 545, + 401 + ], + "lines": [ + { + "bbox": [ + 50, + 256, + 545, + 401 + ], + "spans": [ + { + "bbox": [ + 50, + 256, + 545, + 401 + ], + "type": "image", + "image_path": "1ff4c252e02dde5cca65df01afa591d1d19ab5b6075f95fcc2bdffc1252de5b2.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 403, + 546, + 427 + ], + "lines": [ + { + "bbox": [ + 46, + 403, + 546, + 427 + ], + "spans": [ + { + "bbox": [ + 46, + 403, + 546, + 427 + ], + "type": "text", + "content": "Figure 7: Compared to DreamBooth [28]. Dreambooth struggles with preserving the details of the given objects, especially for complex and lengthy prompts." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 448, + 287, + 543 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 448, + 287, + 543 + ], + "spans": [ + { + "bbox": [ + 46, + 448, + 287, + 543 + ], + "type": "text", + "content": "the seagulls in the same scene. A similar issue is observed in Application 3 (Figure 1), where the general model cannot produce scenes that are uncommon in real-life, such as a lion wearing a crown (Figure 6). In addition, the general model has difficulty understanding the semantics of certain prompts, as observed in the case of \"a bee is making honey\" in Figure 5, where the model only combines the bee and honey in the same scene." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 544, + 287, + 652 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 544, + 287, + 652 + ], + "spans": [ + { + "bbox": [ + 46, + 544, + 287, + 652 + ], + "type": "text", + "content": "The proposed SNB can address these limitations, which integrates a specialized model, such as a model that focuses on cars in Application 1, or a cartoon model in Application 3, to improve the accuracy and realism of image generation. By leveraging the strengths of both the general and specialized models, our proposed approach can generate visually appealing and semantically rich images. This approach has the potential to advance the field of computer vision by enabling more sophisticated and realistic image generation." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 659, + 194, + 672 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 659, + 194, + 672 + ], + "spans": [ + { + "bbox": [ + 47, + 659, + 194, + 672 + ], + "type": "text", + "content": "5.2. Compared to Dreambooth" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "content": "Dreambooth [28] presents an approach for synthesizing novel renditions of a given subject using a few images of the subject and the guidance of a text prompt, i.e., recon" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 448, + 545, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 448, + 545, + 651 + ], + "spans": [ + { + "bbox": [ + 304, + 448, + 545, + 651 + ], + "type": "text", + "content": "textualization. However, it is challenging for Dreambooth to handle certain creative scene compositions, such as “a [] backpack on the moon.” Our empirical investigation reveals that Dreambooth struggles with integrating specific subjects into the scene, particularly in cases where the scenario is uncommon in reality. As illustrated in Figure 7, Dreambooth frequently produces images that either lack or exhibit inconsistencies in terms of specific subjects in such scenarios. In contrast, our approach excels at integrating a specific subject into the scene while maintaining fidelity to the prompt. Although Dreambooth can generate contextually relevant images for brief prompts like “a [] bag on a garden bench,” it may not accurately capture the finer details of the subject, such as the graphic texture of the bag. In contrast, our approach not only generates images that adhere to the prompt but also reproduces subject details with greater accuracy." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 659, + 476, + 672 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 659, + 476, + 672 + ], + "spans": [ + { + "bbox": [ + 306, + 659, + 476, + 672 + ], + "type": "text", + "content": "5.3. Compared to Annotated Masks" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 677, + 546, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 546, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 546, + 715 + ], + "type": "text", + "content": "Blended-Diffusion [3] firstly propose to blend the noisy image in each sampling step based on a given mask for image editing. Such a method can neither handle applica" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "22598" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 70, + 286, + 221 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 286, + 221 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 286, + 221 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 286, + 221 + ], + "type": "image", + "image_path": "ead9e6c9fb6b83d2cd1eee80a6c546e77a66ba3a7fb4c1b600e0984aad70b902.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 223, + 546, + 246 + ], + "lines": [ + { + "bbox": [ + 46, + 223, + 546, + 246 + ], + "spans": [ + { + "bbox": [ + 46, + 223, + 546, + 246 + ], + "type": "text", + "content": "Figure 8: Compared to annotated masks. Our saliency-aware mask achieves better composing performance, e.g., generating snow on the car." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 300, + 70, + 545, + 220 + ], + "blocks": [ + { + "bbox": [ + 300, + 70, + 545, + 220 + ], + "lines": [ + { + "bbox": [ + 300, + 70, + 545, + 220 + ], + "spans": [ + { + "bbox": [ + 300, + 70, + 545, + 220 + ], + "type": "image", + "image_path": "167a05b5a8a58f35dcc27a0fef827436dbd354ea44169497c68330caa77a02a4.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 50, + 258, + 286, + 421 + ], + "blocks": [ + { + "bbox": [ + 50, + 258, + 286, + 421 + ], + "lines": [ + { + "bbox": [ + 50, + 258, + 286, + 421 + ], + "spans": [ + { + "bbox": [ + 50, + 258, + 286, + 421 + ], + "type": "image", + "image_path": "f0a07eba5f8255da381de24fb4ea593582c56421c753f472ef8e471d5bd363fe.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 88, + 427, + 263, + 439 + ], + "lines": [ + { + "bbox": [ + 88, + 427, + 263, + 439 + ], + "spans": [ + { + "bbox": [ + 88, + 427, + 263, + 439 + ], + "type": "text", + "content": "Cross-domain Fusion: A bee is making honey" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 305, + 259, + 545, + 422 + ], + "blocks": [ + { + "bbox": [ + 305, + 259, + 545, + 422 + ], + "lines": [ + { + "bbox": [ + 305, + 259, + 545, + 422 + ], + "spans": [ + { + "bbox": [ + 305, + 259, + 545, + 422 + ], + "type": "image", + "image_path": "b7c16dcb7dc76be9b258e11c5e7e462f5d89e23ad68ac22dc40e05f4c46b52cf.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 322, + 427, + 529, + 449 + ], + "lines": [ + { + "bbox": [ + 322, + 427, + 529, + 449 + ], + "spans": [ + { + "bbox": [ + 322, + 427, + 529, + 449 + ], + "type": "text", + "content": "Recontextualization: [ ] on the sofa in the living room, decorated with green plants and sunny" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 453, + 546, + 478 + ], + "lines": [ + { + "bbox": [ + 46, + 453, + 546, + 478 + ], + "spans": [ + { + "bbox": [ + 46, + 453, + 546, + 478 + ], + "type": "text", + "content": "Figure 9: Compared to weighted sum. Directly averaging the two noises cannot well preserve each model's strengths and leads to cluttered image content." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 498, + 289, + 630 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 498, + 289, + 630 + ], + "spans": [ + { + "bbox": [ + 46, + 498, + 289, + 630 + ], + "type": "text", + "content": "tions like cross-domain fusion nor perform well on a mixed object and scene content, such as \"a car in a snowy forest.\" As depicted in Figure 8, a comparison between our method and a mask-based approach demonstrates that our SNB method accurately preserves detailed subject features influenced by the scene, like the snow on the car's hood and wheels. In contrast, the mask-based method replaces the entire car area, resulting in a loss of subject details within the scene. Overall, our SNB yields more natural and realistic results when editing or replacing scene content, particularly in scenarios with mixed object and scene content." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 644, + 203, + 658 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 644, + 203, + 658 + ], + "spans": [ + { + "bbox": [ + 47, + 644, + 203, + 658 + ], + "type": "text", + "content": "5.4. Compared to Weighted Sum" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "content": "The success of SNB hinges upon its ability to create a high-quality mask based on the noise generated by the two models, which is then used to determine content coverage and retention. As shown in Figure 9, the experimental re" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 498, + 546, + 584 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 498, + 546, + 584 + ], + "spans": [ + { + "bbox": [ + 304, + 498, + 546, + 584 + ], + "type": "text", + "content": "sults of SNB and the fusion method that directly averages the two noises differ significantly. When the weighted sum of two noises is used, the resulting image content appears cluttered and lacks the desired semantic alignment. In contrast, our SNB method outperforms the direct averaging method by achieving precise semantic alignment, resulting in more accurate and realistic image content." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": "It is worth noting that, CDM [18] is belong to the case of weighted sum, which treats two noises equally in different regions, while we trust different models in different regions by designing a saliency-aware fusion mechanism. We further show the comparison results with CDM in Fig. 10. CDM fails to generate accurate car images in the case of complex prompts (left) and tends to produce conceptually mixed images or exhibits unstable performance (right). In contrast, our proposed method can accurately generate specified images of cars as well as vivid depictions" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "22599" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 69, + 286, + 201 + ], + "blocks": [ + { + "bbox": [ + 49, + 69, + 286, + 201 + ], + "lines": [ + { + "bbox": [ + 49, + 69, + 286, + 201 + ], + "spans": [ + { + "bbox": [ + 49, + 69, + 286, + 201 + ], + "type": "image", + "image_path": "5300f61b98b2de7dcef81ecc4a3c08aecb1aeffb169b99faff5671702cc92ae3.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 203, + 286, + 251 + ], + "lines": [ + { + "bbox": [ + 47, + 203, + 286, + 251 + ], + "spans": [ + { + "bbox": [ + 47, + 203, + 286, + 251 + ], + "type": "text", + "content": "Figure 10: Comparisons with CDM. In the case of complex prompts (left), CDM fails to generate accurate car images. Moreover, CDM tends to produce conceptually mixed images (mid) or exhibits unstable performance (right)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 52, + 263, + 282, + 317 + ], + "blocks": [ + { + "bbox": [ + 52, + 263, + 282, + 317 + ], + "lines": [ + { + "bbox": [ + 52, + 263, + 282, + 317 + ], + "spans": [ + { + "bbox": [ + 52, + 263, + 282, + 317 + ], + "type": "table", + "html": "
Text-Image SimilarityImage Similarity
App. 1 ↑App. 3 ↑App. 2 ↑
Ours31.1832.760.8401
Baseline29.5631.010.7582
", + "image_path": "d3a684bef9f0796a0e62c29eb5a87e88f04cf1cc6cf8f3c109b527f7ef35456c.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 59, + 343, + 276, + 372 + ], + "blocks": [ + { + "bbox": [ + 71, + 319, + 261, + 330 + ], + "lines": [ + { + "bbox": [ + 71, + 319, + 261, + 330 + ], + "spans": [ + { + "bbox": [ + 71, + 319, + 261, + 330 + ], + "type": "text", + "content": "Table 1: The CLIP-based Quantitative Metrics." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 59, + 343, + 276, + 372 + ], + "lines": [ + { + "bbox": [ + 59, + 343, + 276, + 372 + ], + "spans": [ + { + "bbox": [ + 59, + 343, + 276, + 372 + ], + "type": "table", + "html": "
App. 1App. 2App. 3
Ours better81.4%84.7%79.3%
", + "image_path": "48eebedbcc82f8b4aa5357607260d712c44d5effc86d85b3d26123412d2e0d4c.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 108, + 374, + 225, + 384 + ], + "lines": [ + { + "bbox": [ + 108, + 374, + 225, + 384 + ], + "spans": [ + { + "bbox": [ + 108, + 374, + 225, + 384 + ], + "type": "text", + "content": "Table 2: Human evaluations." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 47, + 409, + 286, + 433 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 409, + 286, + 433 + ], + "spans": [ + { + "bbox": [ + 47, + 409, + 286, + 433 + ], + "type": "text", + "content": "of lions wearing crowns. Overall, our method demonstrates significantly better performance compared to CDM." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 442, + 167, + 455 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 442, + 167, + 455 + ], + "spans": [ + { + "bbox": [ + 47, + 442, + 167, + 455 + ], + "type": "text", + "content": "5.5.Quantitative Metrics" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 461, + 287, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 461, + 287, + 628 + ], + "spans": [ + { + "bbox": [ + 46, + 461, + 287, + 628 + ], + "type": "text", + "content": "We conducted quantitative evaluations for three corresponding applications. Specifically, we generated 5k test samples for each application to calculate the CLIP-based score. For application 1 and application 3, we measured the similarity between the generated images and the corresponding prompts in terms of Text-Image Similarity; for application 2, we calculated the similarity between the recontextualized images and the input images, which is referred to as Image Similarity. The evaluation results are presented in Table 1. Stable diffusion serves as the baseline for application 1 and application 3, while Dreambooth [28] serves as the baseline for application 2. Based on the results, it can be concluded that our method has demonstrated improved performance across all three applications." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 630, + 287, + 714 + ], + "type": "text", + "content": "In addition, we also conducted 500 human evaluations for each application and presented the results in Table 2. In application 1 and application 3, we compare our model to stable diffusion, and in application 2, we compare it to Dreambooth. The data indicate that for all three applications, the majority of the participants regarded the images generated by our method as superior in quality." + } + ] + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 307, + 69, + 545, + 224 + ], + "blocks": [ + { + "bbox": [ + 307, + 69, + 545, + 224 + ], + "lines": [ + { + "bbox": [ + 307, + 69, + 545, + 224 + ], + "spans": [ + { + "bbox": [ + 307, + 69, + 545, + 224 + ], + "type": "image", + "image_path": "0ed7c819e06ef13978e427a7e5b24dc22ee47eb4d3f04f2646edd9ab6f1cf61f.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 228, + 545, + 251 + ], + "lines": [ + { + "bbox": [ + 305, + 228, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 305, + 228, + 545, + 251 + ], + "type": "text", + "content": "Figure 11: Failure cases. Misalignments may appear due to the various car size." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 272, + 378, + 285 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 272, + 378, + 285 + ], + "spans": [ + { + "bbox": [ + 306, + 272, + 378, + 285 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 292, + 545, + 422 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 292, + 545, + 422 + ], + "spans": [ + { + "bbox": [ + 304, + 292, + 545, + 422 + ], + "type": "text", + "content": "In this work, we study the problem of integrating pretrained text-guided diffusion models to achieve more controllable generation. We propose a simple yet effective Saliency-aware Noise Blending (SNB) to preserve the strengths of each individual model. Extensive experiments on three challenging applications (i.e., a general model + a cartoon model, a fine-grained car model, and a Dream-Booth model) show that SNB can significantly empower pre-trained diffusion models. With the rapid development of pre-trained large generative models, we believe our work is of great value." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 423, + 545, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 423, + 545, + 567 + ], + "spans": [ + { + "bbox": [ + 304, + 423, + 545, + 567 + ], + "type": "text", + "content": "Limitations. Although our method has demonstrated significant performance improvements, it may not be applicable in certain scenarios. The advantage of SNB is its ability to form automatic masks based on saliency response values; however, when the difference in object size between the two merged images is too large, semantic alignment can be difficult to achieve. As shown in Figure 11, when the general model produces cars that are either too large or too small, the results display misaligned semantic positions. In the future, we will keep on studying the integration of different large generative models and extend our method to more general settings." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 578, + 403, + 591 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 578, + 403, + 591 + ], + "spans": [ + { + "bbox": [ + 306, + 578, + 403, + 591 + ], + "type": "text", + "content": "Acknowledgments" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 597, + 545, + 681 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 597, + 545, + 681 + ], + "spans": [ + { + "bbox": [ + 304, + 597, + 545, + 681 + ], + "type": "text", + "content": "This work was partially supported by the National Natural Science Foundation of China: No. 91948303-1, 611803375, No. 61803375, No. 12002380, No. 62106278, No. 62101575, No. 61906210; the Postgraduate Scientific Research Innovation Project of Hunan Province: QL20210018 and the National Key R&D Program of China (2021ZD0140301)." + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "22600" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 286, + 712 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 53, + 91, + 286, + 123 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 286, + 123 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 286, + 123 + ], + "type": "text", + "content": "[1] Fine-tuned stable diffusion model trained on screenshots from a popular animation studio. https://huggingface.co/nitrosocke/mo-di-diffusion.2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 124, + 286, + 146 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 124, + 286, + 146 + ], + "spans": [ + { + "bbox": [ + 53, + 124, + 286, + 146 + ], + "type": "text", + "content": "[2] Merging two diffusion models. https://stable-diffusion-art.com/models/#merging_two_models. 2022." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 148, + 286, + 190 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 148, + 286, + 190 + ], + "spans": [ + { + "bbox": [ + 53, + 148, + 286, + 190 + ], + "type": "text", + "content": "[3] Omri Avrahami, Dani Lischinski, and Ohad Fried. Blended diffusion for text-driven editing of natural images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18208-18218, 2022." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 192, + 286, + 246 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 192, + 286, + 246 + ], + "spans": [ + { + "bbox": [ + 53, + 192, + 286, + 246 + ], + "type": "text", + "content": "[4] Yogesh Balaji, Seungjun Nah, Xun Huang, Arash Vahdat, Jiaming Song, Karsten Kreis, Miika Aittala, Timo Aila, Samuli Laine, Bryan Catanzaro, et al. eDIFF-I: Text-to-image diffusion models with an ensemble of expert denoisers. arXiv preprint arXiv:2211.01324, 2022." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 247, + 286, + 301 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 247, + 286, + 301 + ], + "spans": [ + { + "bbox": [ + 53, + 247, + 286, + 301 + ], + "type": "text", + "content": "[5] Huiwen Chang, Han Zhang, Jarred Barber, AJ Maschinot, Jose Lezama, Lu Jiang, Ming-Hsuan Yang, Kevin Murphy, William T Freeman, Michael Rubinstein, et al. Muse: Text-to-image generation via masked generative transformers. arXiv preprint arXiv:2301.00704, 2023." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 302, + 286, + 334 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 302, + 286, + 334 + ], + "spans": [ + { + "bbox": [ + 53, + 302, + 286, + 334 + ], + "type": "text", + "content": "[6] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Advances in Neural Information Processing Systems, 34:8780-8794, 2021." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 335, + 286, + 390 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 335, + 286, + 390 + ], + "spans": [ + { + "bbox": [ + 53, + 335, + 286, + 390 + ], + "type": "text", + "content": "[7] Ming Ding, Zhuoyi Yang, Wenyi Hong, Wendi Zheng, Chang Zhou, Da Yin, Junyang Lin, Xu Zou, Zhou Shao, Hongxia Yang, et al. Cogview: Mastering text-to-image generation via transformers. Advances in Neural Information Processing Systems, 34:19822-19835, 2021." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 391, + 286, + 434 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 391, + 286, + 434 + ], + "spans": [ + { + "bbox": [ + 53, + 391, + 286, + 434 + ], + "type": "text", + "content": "[8] Patrick Esser, Robin Rombach, and Bjorn Ommer. Taming transformers for high-resolution image synthesis. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 12873-12883, 2021." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 435, + 286, + 489 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 435, + 286, + 489 + ], + "spans": [ + { + "bbox": [ + 53, + 435, + 286, + 489 + ], + "type": "text", + "content": "[9] Rinon Gal, Yuval Alaluf, Yuval Atzmon, Or Patashnik, Amit H Bermano, Gal Chechik, and Daniel Cohen-Or. An image is worth one word: Personalizing text-to-image generation using textual inversion. arXiv preprint arXiv:2208.01618, 2022." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 491, + 286, + 544 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 491, + 286, + 544 + ], + "spans": [ + { + "bbox": [ + 48, + 491, + 286, + 544 + ], + "type": "text", + "content": "[10] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. Journal of Japan Society for Fuzzy Theory and Intelligent Informatics, 2014." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 546, + 286, + 567 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 546, + 286, + 567 + ], + "spans": [ + { + "bbox": [ + 48, + 546, + 286, + 567 + ], + "type": "text", + "content": "[11] D Gopika and B Azhagusundari. An analysis on ensemble methods in classification tasks. 2014." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 569, + 286, + 612 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 569, + 286, + 612 + ], + "spans": [ + { + "bbox": [ + 48, + 569, + 286, + 612 + ], + "type": "text", + "content": "[12] Tobias Hinz, Stefan Heinrich, and Stefan Wermter. Semantic object accuracy for generative text-to-image synthesis. IEEE transactions on pattern analysis and machine intelligence, 44(3):1552-1565, 2020." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 613, + 286, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 613, + 286, + 635 + ], + "spans": [ + { + "bbox": [ + 48, + 613, + 286, + 635 + ], + "type": "text", + "content": "[13] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. arXiv preprint arXiv:2207.12598, 2022." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 636, + 286, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 636, + 286, + 679 + ], + "spans": [ + { + "bbox": [ + 48, + 636, + 286, + 679 + ], + "type": "text", + "content": "[14] Nupur Kumari, Richard Zhang, Eli Shechtman, and Jun-Yan Zhu. Ensembling off-the-shelf models for gan training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10651-10662, 2022." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 681, + 286, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 681, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 681, + 286, + 712 + ], + "type": "text", + "content": "[15] Bowen Li, Xiaojuan Qi, Thomas Lukasiewicz, and Philip Torr. Controllable text-to-image generation. Advances in Neural Information Processing Systems, 32, 2019." + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 31, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "text", + "content": "[16] Gang Li, Heliang Zheng, Chaoyue Wang, Chang Li, Changwen Zheng, and Dacheng Tao. 3ddesigner: Towards photorealistic 3d object generation and editing with text-guided diffusion models. arXiv preprint arXiv:2211.14108, 2022." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 118, + 545, + 172 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 545, + 172 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 545, + 172 + ], + "type": "text", + "content": "[17] Wenbo Li, Pengchuan Zhang, Lei Zhang, Qiuyuan Huang, Xiaodong He, Siwei Lyu, and Jianfeng Gao. Object-driven text-to-image synthesis via adversarial training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12174-12182, 2019." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 175, + 545, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 175, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 307, + 175, + 545, + 228 + ], + "type": "text", + "content": "[18] Nan Liu, Shuang Li, Yilun Du, Antonio Torralba, and Joshua B. Tenenbaum. Compositional visual generation with composable diffusion models. In ECCV (17), volume 13677 of Lecture Notes in Computer Science, pages 423-439. Springer, 2022." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 230, + 545, + 273 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 230, + 545, + 273 + ], + "spans": [ + { + "bbox": [ + 308, + 230, + 545, + 273 + ], + "type": "text", + "content": "[19] Joao Mendes-Moreira, Carlos Soares, Alipio Mário Jorge, and Jorge Freire De Sousa. Ensemble approaches for regression: A survey. Acm computing surveys (csur), 45(1):1-40, 2012." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 275, + 545, + 329 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 275, + 545, + 329 + ], + "spans": [ + { + "bbox": [ + 308, + 275, + 545, + 329 + ], + "type": "text", + "content": "[20] Alex Nichol, Prafulla Dhariwal, Aditya Ramesh, Pranav Shyam, Pamela Mishkin, Bob McGrew, Ilya Sutskever, and Mark Chen. Glide: Towards photorealistic image generation and editing with text-guided diffusion models. arXiv preprint arXiv:2112.10741, 2021." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 331, + 545, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 331, + 545, + 374 + ], + "spans": [ + { + "bbox": [ + 308, + 331, + 545, + 374 + ], + "type": "text", + "content": "[21] Tingting Qiao, Jing Zhang, Duanqing Xu, and Dacheng Tao. Learn, imagine and create: Text-to-image generation from prior knowledge. Advances in neural information processing systems, 32, 2019." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 376, + 545, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 376, + 545, + 430 + ], + "spans": [ + { + "bbox": [ + 308, + 376, + 545, + 430 + ], + "type": "text", + "content": "[22] Tingting Qiao, Jing Zhang, Duanqing Xu, and Dacheng Tao. Mirrorgan: Learning text-to-image generation by redescription. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1505-1514, 2019." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 432, + 545, + 474 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 432, + 545, + 474 + ], + "spans": [ + { + "bbox": [ + 308, + 432, + 545, + 474 + ], + "type": "text", + "content": "[23] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 477, + 545, + 520 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 477, + 545, + 520 + ], + "spans": [ + { + "bbox": [ + 308, + 477, + 545, + 520 + ], + "type": "text", + "content": "[24] Aditya Ramesh, Mikhail Pavlov, Gabriel Goh, Scott Gray, Chelsea Voss, Alec Radford, Mark Chen, and Ilya Sutskever. Zero-shot text-to-image generation. In International Conference on Machine Learning, pages 8821-8831. PMLR, 2021." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 522, + 545, + 564 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 522, + 545, + 564 + ], + "spans": [ + { + "bbox": [ + 308, + 522, + 545, + 564 + ], + "type": "text", + "content": "[25] Ye Ren, PN Suganthan, and N Srikanth. Ensemble methods for wind and solar power forecasting—a state-of-the-art review. Renewable and Sustainable Energy Reviews, 50:82-91, 2015." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 567, + 545, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 567, + 545, + 588 + ], + "spans": [ + { + "bbox": [ + 308, + 567, + 545, + 588 + ], + "type": "text", + "content": "[26] Lior Rokach. Ensemble-based classifiers. Artificial intelligence review, 33:1-39, 2010." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 590, + 545, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 590, + 545, + 644 + ], + "spans": [ + { + "bbox": [ + 308, + 590, + 545, + 644 + ], + "type": "text", + "content": "[27] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684-10695, 2022." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 647, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 647, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 647, + 545, + 689 + ], + "type": "text", + "content": "[28] Nataniel Ruiz, Yuanzhen Li, Varun Jampani, Yael Pritch, Michael Rubinstein, and Kfir Aberman. Dreambooth: Fine tuning text-to-image diffusion models for subject-driven generation. arXiv preprint arXiv:2208.12242, 2022." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "text", + "content": "[29] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed" + } + ] + } + ], + "index": 30 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "text", + "content": "22601" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 712 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 117 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 117 + ], + "type": "text", + "content": "Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 119, + 287, + 185 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 119, + 287, + 185 + ], + "spans": [ + { + "bbox": [ + 48, + 119, + 287, + 185 + ], + "type": "text", + "content": "[30] Chitwan Saharia, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 186, + 288, + 252 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 186, + 288, + 252 + ], + "spans": [ + { + "bbox": [ + 48, + 186, + 288, + 252 + ], + "type": "text", + "content": "[31] Christoph Schuhmann, Romain Beaumont, Richard Vencu, Cade Gordon, Ross Wightman, Mehdi Cherti, Theo Coombes, Aarush Katta, Clayton Mullis, Mitchell Wortsman, et al. Laion-5b: An open large-scale dataset for training next generation image-text models. arXiv preprint arXiv:2210.08402, 2022." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 255, + 287, + 299 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 255, + 287, + 299 + ], + "spans": [ + { + "bbox": [ + 48, + 255, + 287, + 299 + ], + "type": "text", + "content": "[32] Jascha Sohl-Dickstein, Eric Weiss, Niru Maheswaranathan, and Surya Ganguli. Deep unsupervised learning using nonequilibrium thermodynamics. In International Conference on Machine Learning, pages 2256-2265. PMLR, 2015." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 301, + 287, + 333 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 301, + 287, + 333 + ], + "spans": [ + { + "bbox": [ + 48, + 301, + 287, + 333 + ], + "type": "text", + "content": "[33] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. arXiv preprint arXiv:2010.02502, 2020." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 335, + 287, + 380 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 335, + 287, + 380 + ], + "spans": [ + { + "bbox": [ + 48, + 335, + 287, + 380 + ], + "type": "text", + "content": "[34] Ming Tao, Hao Tang, Songsong Wu, Nicu Sebe, Xiao-Yuan Jing, Fei Wu, and Bingkun Bao. Df-gan: Deep fusion generative adversarial networks for text-to-image synthesis. arXiv preprint arXiv:2008.05865, 2020." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 382, + 288, + 425 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 382, + 288, + 425 + ], + "spans": [ + { + "bbox": [ + 48, + 382, + 288, + 425 + ], + "type": "text", + "content": "[35] Sandro Vega-Pons and José Ruiz-Shulcloper. A survey of clustering ensemble algorithms. International Journal of Pattern Recognition and Artificial Intelligence, 25(03):337-372, 2011." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 428, + 287, + 472 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 428, + 287, + 472 + ], + "spans": [ + { + "bbox": [ + 48, + 428, + 287, + 472 + ], + "type": "text", + "content": "[36] Huikai Wu, Shuai Zheng, Junge Zhang, and Kaiqi Huang. Gp-gan: Towards realistic high-resolution image blending. In Proceedings of the 27th ACM international conference on multimedia, pages 2487-2495, 2019." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 474, + 287, + 518 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 474, + 287, + 518 + ], + "spans": [ + { + "bbox": [ + 48, + 474, + 287, + 518 + ], + "type": "text", + "content": "[37] Tao Xu, Pengchuan Zhang, Qiuyuan Huang, Han Zhang, Zhe Gan, Xiaolei Huang, and Xiaodong He. Attngan: Fine-grained text to image generation with attentional generative adversarial networks. Cornell University - arXiv, 2017." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 520, + 287, + 574 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 520, + 287, + 574 + ], + "spans": [ + { + "bbox": [ + 48, + 520, + 287, + 574 + ], + "type": "text", + "content": "[38] Linjie Yang, Ping Luo, Chen Change Loy, and Xiaou Tang. A large-scale car dataset for fine-grained categorization and verification. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3973-3981, 2015." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 577, + 287, + 610 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 577, + 287, + 610 + ], + "spans": [ + { + "bbox": [ + 48, + 577, + 287, + 610 + ], + "type": "text", + "content": "[39] Pengyi Yang, Yee Hwa Yang, Bing B Zhou, and Albert Y Zomaya. A review of ensemble methods in bioinformatics. Current Bioinformatics, 5(4):296-308, 2010." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 613, + 287, + 655 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 613, + 287, + 655 + ], + "spans": [ + { + "bbox": [ + 48, + 613, + 287, + 655 + ], + "type": "text", + "content": "[40] Hui Ye, Xiulong Yang, Martin Takac, Rajshekhar Sunderraman, and Shihao Ji. Improving text-to-image synthesis using contrastive learning. arXiv preprint arXiv:2107.02423, 2021." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 658, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 658, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 658, + 287, + 712 + ], + "type": "text", + "content": "[41] Han Zhang, Jing Yu Koh, Jason Baldridge, Honglak Lee, and Yinfei Yang. Cross-modal contrastive learning for text-to-image generation. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 833-842, 2021." + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 546, + 273 + ], + "type": "list", + "angle": 0, + "index": 18, + "blocks": [ + { + "bbox": [ + 307, + 73, + 546, + 126 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 546, + 126 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 546, + 126 + ], + "type": "text", + "content": "[42] Zizhao Zhang, Yuanpu Xie, and Lin Yang. Photographic text-to-image synthesis with a hierarchically-nested adversarial network. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 6199-6208, 2018." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 129, + 546, + 172 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 129, + 546, + 172 + ], + "spans": [ + { + "bbox": [ + 307, + 129, + 546, + 172 + ], + "type": "text", + "content": "[43] Jing Zhao, Heliang Zheng, Chaoyue Wang, Long Lan, Wanrong Huang, and Wenjing Yang. Null-text guidance in diffusion models is secretly a cartoon-style creator. arXiv preprint arXiv:2305.06710, 2023." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 175, + 546, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 175, + 546, + 217 + ], + "spans": [ + { + "bbox": [ + 307, + 175, + 546, + 217 + ], + "type": "text", + "content": "[44] Ying Zhao, Jun Gao, and Xuezhi Yang. A survey of neural network ensembles. In 2005 international conference on neural networks and brain, volume 1, pages 438-442. IEEE, 2005." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 219, + 546, + 273 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 219, + 546, + 273 + ], + "spans": [ + { + "bbox": [ + 307, + 219, + 546, + 273 + ], + "type": "text", + "content": "[45] Minfeng Zhu, Pingbo Pan, Wei Chen, and Yi Yang. Dm-gan: Dynamic memory generative adversarial networks for text-to-image synthesis. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 5802-5810, 2019." + } + ] + } + ], + "index": 17 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 749, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 318, + 757 + ], + "type": "text", + "content": "22602" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/d0a41b80-a701-4955-834c-d42058b2d111_content_list.json b/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/d0a41b80-a701-4955-834c-d42058b2d111_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..9bceab017aa9a0b7bec48a0f9e8f54a5ada25a24 --- /dev/null +++ b/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/d0a41b80-a701-4955-834c-d42058b2d111_content_list.json @@ -0,0 +1,1786 @@ +[ + { + "type": "text", + "text": "Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding", + "text_level": 1, + "bbox": [ + 115, + 144, + 852, + 186 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Ziyang Yuan $^{1*}$ Yiming Zhu $^{1,2*}$ Yu Li $^{2\\dagger}$ Hongyu Liu $^{3}$ Chun Yuan $^{1\\dagger}$", + "bbox": [ + 196, + 211, + 791, + 228 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{1}$ Tsinghua Shenzhen International Graduate School $^{2}$ International Digital Economy Academy (IDEA) $^{3}$ Hong Kong University of Science and Technology", + "bbox": [ + 87, + 228, + 909, + 260 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "https://eg3d-goae.github.io", + "bbox": [ + 376, + 262, + 618, + 274 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/ff4e090a71aaba990dfbc75a0a5c1a02ec427b18c727a3c606c60c5cc096ee83.jpg", + "image_caption": [ + "Figure 1: The inversion and editing results of our method on human portraits and cat images. The novel view synthesized images demonstrate that our method can achieve high-quality inversion and editing given a single image input." + ], + "image_footnote": [], + "bbox": [ + 99, + 290, + 868, + 501 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 552, + 310, + 565 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "3D GAN inversion aims to achieve high reconstruction fidelity and reasonable 3D geometry simultaneously from a single image input. However, existing 3D GAN inversion methods rely on time-consuming optimization for each individual case. In this work, we introduce a novel encoder-based inversion framework based on EG3D, one of the most widely-used 3D GAN models. We leverage the inherent properties of EG3D's latent space to design a discriminator and a background depth regularization. This enables us to train a geometry-aware encoder capable of converting the input image into corresponding latent code. Additionally, we explore the feature space of EG3D and develop an adaptive refinement stage that improves the representation ability of features in EG3D to enhance the recovery of fine-grained textural details. Finally, we propose an occlusion-aware fusion operation to prevent distortion in unobserved regions. Our method achieves impressive results comparable to optimization-based methods while operating up to 500 times faster. Our framework is well-suited for applications such as semantic editing.", + "bbox": [ + 75, + 571, + 468, + 847 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 500, + 552, + 630, + 565 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Recent advances in 3D-aware generative adversarial networks (GAN) (e.g. [5, 6, 14, 32]) have integrated neural radiance fields (NeRF) [27] into style-based generation, resulting in remarkable success in generating highly realistic 3D portraits. Similar to 2D GAN inversion techniques, 3D GAN inversion also projects images into the latent space of pre-trained 3D GAN models. However, in addition to pursuing faithful image reconstruction and preserving fined details, 3D GAN inversion also aims for accurate 3D geometry, which is critical for generating realistic and consistent multi-view images. This ability to ensure the correctness of 3D geometry is a crucial advantage of 3D GAN inversion over its 2D counterpart.", + "bbox": [ + 497, + 574, + 890, + 755 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Some optimization-based methods, such as [21, 47, 49], first invert the image to a latent code to obtain a coarse 3D shape. They then synthesize pseudo-multi-view images with this shape using a warping process. These pseudo images are used as supervision to optimize the parameters of the 3D GAN for more precise 3D geometry and better detail preservation. While these iterative optimization-based pipelines can prevent shape collapse and produce accurate", + "bbox": [ + 497, + 755, + 892, + 866 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 129, + 49, + 200, + 84 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 253, + 48, + 789, + 86 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "* Equal contributions; † Corresponding author.", + "bbox": [ + 100, + 853, + 349, + 866 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "2437", + "bbox": [ + 468, + 885, + 500, + 897 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "results, the optimization process needs to be performed for each individual case, which is time-consuming and impractical for many applications.", + "bbox": [ + 75, + 125, + 468, + 167 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Several encoder-based methods [22, 23] leverage a pretrained 3D GAN to generate proxy data by randomly sampling latent codes and camera poses. They then employ these paired proxy data to train an encoder in a self-supervised fashion and further refine features in 3D GAN. These encoder-based techniques offer higher efficiency but lower high-fidelity reconstruction ability. Moreover, due to a domain gap between the paired proxy data and real images, the encoder may invert the in-the-wild images to unsuitable latent codes. To address this issue, we study the properties of the latent space in 3D GAN and develop a geometry-aware encoder that predicts the latent code incorporating these properties. Furthermore, since the latent code can not preserve details of input images well, we explore the characteristics of feature space in 3D GAN to help our method improve the performance in reconstructing the original appearance. The latent and feature spaces are widely discussed in 2D GAN inversion [11, 24, 42].", + "bbox": [ + 75, + 169, + 468, + 419 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "This paper presents a novel encoder-based method for inverting 3D images generated by EG3D [5], a well-known and high-quality 3D GAN. Our approach is simple yet effective and is based on the discovery of a specific latent space within EG3D, which we call the canonical latent space $\\mathcal{W}_c$ . We find that latent codes belonging to this space can produce human faces with superior 3D shape and texture quality following two principles. Firstly, the input pose before the mapping network of EG3D must be a static canonical pose throughout the generation process. Secondly, the depth of the background should fall within a fixed range. Based on this, we propose using an encoder to invert the image into this canonical latent space using a proposed latent code discriminator and depth regularization. Although our encoder produces a suitable latent code that preserves the reasonable 3D shape of the input image, but the code is low dimension, making it challenging to capture texture details. To address this, similar to the 2D GAN inversion [3, 45], we refine the selected features in EG3D based on the residual between the input image and reconstruction image with predicted latent code. Meanwhile, we also find there is a canonical feature space $\\mathcal{F}_c$ in EG3D, so we design an alignment module to project the refined feature to the canonical feature space. Moreover, we introduce an occlusion-aware fusion operation to avoid texture and shape distortions in reconstructing invisible regions.", + "bbox": [ + 75, + 421, + 468, + 781 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We conduct comprehensive experiments to evaluate the efficiency and effectiveness of our method, and the results demonstrate that our method achieves high-quality inversion comparable to optimization-based methods and superior to other encoder-based methods. We also demonstrate our approach is effective in 3D-aware editing applications.", + "bbox": [ + 75, + 783, + 468, + 866 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "See Fig. 1 for some examples of inversion and editing of human portraits and cat faces obtained by our method. Our contribution can be summarised as following:", + "bbox": [ + 497, + 125, + 892, + 168 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We conduct an exploration on the latent space and feature space of EG3D and discover the presence of a canonical attribute.", + "- Based on our analysis of the characteristics of the canonical latent space, we propose a geometry-aware encoder by utilizing a canonical latent discriminator and depth regularization.", + "- We introduce an alignment module based on the canonical feature space and an occlusion-aware method to refine the selected features of the generator and supplement high-quality details.", + "- The proposed method exhibits competitive performance with existing methods in human portraits, both qualitatively and quantitatively. Additionally, our method can also generalize to the cat faces and is effective in 3D editing tasks." + ], + "bbox": [ + 517, + 175, + 890, + 404 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 499, + 418, + 640, + 432 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Generative 3D-Aware Image Synthesis.", + "text_level": 1, + "bbox": [ + 499, + 441, + 833, + 456 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Generative Adversarial Network [13] made significant advancements in generating both 2D photorealistic images [19, 20] and 3D-Aware consistent images. In 3D-aware image generation, some works build 3D GAN based on explicit 3D representations, such as point-cloud [41], voxel [28, 29, 43], and mesh [12, 15, 17]. However, these models often fail to generate high-resolution 3D scenes with high-quality details.", + "bbox": [ + 497, + 461, + 890, + 572 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Since NeRF [27] achieved outstanding multi-view image synthesis, a sequence of works has begun to use implicit 3D representation and volume rendering for 3D generation [5, 6, 10, 14, 30, 32]. Pi-GAN [6] is the first attempt at using GAN to generate NeRF for 3D-aware image synthesis. After that, StyleNeRF [14] proposes a view-consistent upsampling module to generate high-resolution images. StyleSDF [32] combines an SDF-based volume renderer and a 2D CNN network to obtain geometry information. GRAM [10] introduces 2D manifolds to regulate point sampling strategy in volume rendering. EG3D [5] leverages StyleGAN2 [20]'s structure and designs a computationally efficient 3D representation called tri-plane. It can synthesize high-resolution view-consistent images and produces high-quality 3D geometry. We explore EG3D's latent space and build our inversion encoder based on EG3D.", + "bbox": [ + 497, + 573, + 890, + 793 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. GAN Inversion", + "text_level": 1, + "bbox": [ + 499, + 802, + 653, + 817 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "GAN Inversion is an inverse process of the generation that projects the given image to corresponding latent code for faithful reconstruction from the source image. Thus,", + "bbox": [ + 497, + 824, + 890, + 866 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "2438", + "bbox": [ + 468, + 885, + 500, + 897 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/dd8a273f71849cc80a28a40c177d163c1ab973c17154fd15b150f6595884c7f2.jpg", + "image_caption": [ + "Figure 2: Recap of EG3D. $z, p$ denotes a Gaussian sample and a pose condition. The relation of $w, F$ , and tri-plane is illustrated." + ], + "image_footnote": [], + "bbox": [ + 87, + 122, + 458, + 214 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "the image editing process can be conducted by semantic editing on the latent code [33, 37, 51]. In 2D GAN, inversion methods are mainly divided into three categories. Optimization-based methods [1, 8, 46] optimize the generator's latent code or parameters both, achieve high reconstruction quality, but are time-consuming. Encoder-based methods [2, 35, 42] train an encoder to project input images to the latent codes. These methods can get faster inference than optimization-based methods but unsatisfactory inversion fidelity. Hybrid methods [4, 36, 51] use an encoder to get a latent as initialization, then optimize the latent code and generator parameters, which is still time-consuming.", + "bbox": [ + 75, + 283, + 468, + 448 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Unlike 2D methods, 3D GAN Inversion should also consider multi-view-consistence. Directly transferring 2D methods to the 3D inversion is prone to suffering geometry collapse and artifacts. To solve it, Pose Opt. [21] jointly optimizes camera pose, latent codes, and generator parameters. HFGI3D [47] is an optimization-based method that extracts mesh to create pseudo-multi-view supervision. Meanwhile, encoder methods are also gradually developing. IDE-3D [40] uses semantic segmentation to re-train EG3D and learns an encoder for inversion to edit images. NeRF-3DE [23] uses identity contrastive learning to train a based encoder and then trains a refining encoder for better details. E3DGE [22] trains a base encoder to learn coarse shape and texture and supplements local details with pixel-aligned features. However, existing encoder-based methods [22, 23] rely on synthetic paired data and may not generalize well to real-world scenarios. None of the state-of-the-art methods can handle time efficiency and 3D inversion quality simultaneously.", + "bbox": [ + 75, + 451, + 470, + 714 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. EG3D Exploration", + "text_level": 1, + "bbox": [ + 75, + 730, + 258, + 745 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this section, we first briefly review the EG3D model. Then, we explore and analyze the properties of latent space and feature space in EG3D.", + "bbox": [ + 75, + 754, + 468, + 796 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The pipeline of EG3D is shown in Fig 2. It first combines a Gaussian vector $z$ and a pose condition $p$ as input and builds a mapper to generate a latent code $w$ , this process can be denoted as $w = \\text{mapping}(z, p)$ . Then this latent code $w$ will be sent to each layer of a style-based hierarchical gen", + "bbox": [ + 75, + 796, + 468, + 866 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "erator to obtain the feature maps $F$ . These feature maps are enlarged layer by layer. The last layer's feature map reshape to tri-plane, an efficient 3D representation consists of three axis-aligned feature planes $(F_{xy}, F_{xz}, F_{yz})$ . With this efficient 3D representation, EG3D samples point features from the tri-plane to synthesize multi-view images or depths by a rendering decoder $R_{dec}$ with volume rendering [27]. Similar to the 2D GAN, the latent code $w$ belongs to a latent space $\\mathcal{W}$ , and all feature maps in the generator construct the $\\mathcal{F}$ space.", + "bbox": [ + 497, + 125, + 890, + 264 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Canonical Latent Space $\\mathcal{W}_c$", + "text_level": 1, + "bbox": [ + 497, + 277, + 744, + 293 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In order to investigate the properties of the latent space $\\mathcal{W}$ and its relationship with pose conditioning, we adopt a fixed $z$ and sample various pose conditions to generate corresponding latent code $w$ . Fig. 3 illustrates that when $w$ is conditioned on an unsuitable pose $p$ far away from the canonical pose, the generated 3D shapes fail to generalize to other views synthesis. Only when the pose condition is canonical can the synthesized images maintain shape and texture consistency across multiple views. Meanwhile, we find a clear depth gap between the face and background regions when generating good results with the canonical pose condition. Under canonical pose, the depth of the background is restricted to a fixed range, while the face and background regions are confused for the other pose conditions.", + "bbox": [ + 497, + 301, + 890, + 507 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "These observations lead us to identify a specific subspace of $\\mathcal{W}$ intuitively, which we call canonical latent space, denoted as $\\mathcal{W}_c$ , that is responsible for ensuring reasonable 3D shape and texture across multiple views. There are two principles of this canonical latent space. Firstly, the input pose before the mapping network of EG3D must be a static canonical pose. Secondly, the depth of the background should fall within a fixed range to distinguish the face and background regions. Based on these findings, we propose that a high-quality 3D-GAN inversion method should first retrieve a $w$ latent code in $\\mathcal{W}_c$ to ensure the best possible image synthesis results.", + "bbox": [ + 497, + 510, + 892, + 676 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Canonical Feature Space $\\mathcal{F}_c$", + "text_level": 1, + "bbox": [ + 497, + 690, + 749, + 706 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To analyze the characteristics of $\\mathcal{F}$ space, we generate the latent codes with different pose conditions to synthesize multiple tri-planes. We visualize the tri-plane as illustrated in Fig 3. The tri-plane also represents a canonical view when the pose condition is canonical (i.e., the columns $\\mathrm{g} \\sim \\mathrm{i}$ in row $\\mathrm{L}_2$ ). It indicates that there is also a specific subspace of $\\mathcal{F}$ , we call it canonical feature space, denoted as $\\mathcal{F}_c$ , and the canonical latent space $\\mathcal{W}_c$ produces the canonical feature space $\\mathcal{F}_c$ with the generator layers. The $\\mathcal{F}_c$ can supply sufficient facial information for rendering multi-view images.", + "bbox": [ + 497, + 713, + 890, + 866 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "2439", + "bbox": [ + 468, + 885, + 500, + 897 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/de5cd014efd237fc56102bee1b6e8ef4ca24f9fb81acddfdcfe8d6b23a5a3ee9.jpg", + "image_caption": [ + "Figure 3: Illustration of canonical Pose condition. We synthesize multi-view images for three pose conditions $p$ , including left, right, and canonical. As shown in a $\\sim$ c, the canonical pose condition in row $L_2$ has no distortion face shape. Moreover, depth maps in row $L_2$ demonstrate that images on the canonical pose condition have significant foreground and background differences. In contrast, flattened shape depth maps in rows $L_1$ and $L_3$ have foreground and background confusion. Columns $g \\sim i$ reveal the tri-plane is also related to the pose condition." + ], + "image_footnote": [], + "bbox": [ + 78, + 106, + 361, + 328 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/2a8c83275cf93259cce48a9c9c7a81e64fc91c8b5a1253cf572403cd3a7983d2.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 368, + 106, + 616, + 328 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/dbccfbbc7ec4150e734c740ab84ba1015919e167031e77aa31ecd59b4d154d8c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 621, + 106, + 889, + 324 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. Method", + "text_level": 1, + "bbox": [ + 75, + 415, + 168, + 429 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The pipeline of our method is shown in Fig. 4. We first project the input image $I$ to the latent code $w^{+} \\subset \\mathbb{R}^{14 \\times 512}$ with our encoder, where $w^{+} = (w_{0}, w_{1}, \\dots, w_{13})$ is an extension of latent code $w$ and can preserve the details better as mentioned in 2D GAN inversion [35, 42]. Then we calculate the residual between $I$ and the generated image $I_{w^{+}}$ based on $w^{+}$ to refine the features of the generator. In the following Sec. 4.1 and Sec. 4.2, we will describe how we ensure the latent code $w^{+}$ and refined feature belong to the canonical space, respectively. Furthermore, we introduce an occlusion-aware mix tri-plane in Sec. 4.3 to avoid the distortion of invisible regions reconstruction. In Sec. 4.4, we exhibit how to perform 3D semantic editing with our inversion method.", + "bbox": [ + 75, + 438, + 473, + 631 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Geometry-aware Encoder", + "text_level": 1, + "bbox": [ + 75, + 641, + 312, + 656 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We design a geometry-aware encoder to obtain the latent code $w^{+}$ given the input image $I$ and corresponding rendering camera pose $c$ . We generate the inverted latent code $w^{+}$ according to the backbone's pyramid feature progressively. It is worth noting that we choose Swin-transformer [25] as the backbone and further add attention modules at different scale feature layers for different level latent codes (more details of encoder architecture are in supplementary materials). After projecting the input image to the latent code $w^{+}$ , we can synthesize the tri-plane $w^{+}$ through EG3D generator $G$ and use rendering decoder $R_{dec}$ to get the reconstruction image $I_{w^{+}}$ under the rendering camera pose $c$ .", + "bbox": [ + 75, + 662, + 468, + 828 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nw ^ {+} = E (I), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 205, + 839, + 468, + 859 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nI _ {w ^ {+}} = R _ {d e c} (G (w ^ {+}), c)\n$$\n", + "text_format": "latex", + "bbox": [ + 203, + 856, + 342, + 869 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To make the inverted $w^{+}$ not deviate far from the canonical space $\\mathcal{W}_c$ discussed in Sec. 3.1, we use a canonical latent discriminator [31] to discriminate between $w_{c} \\in \\mathcal{W}_{c}$ and $w^{+}$ . The canonical latent discriminator, denoted as $\\mathcal{D}_{\\mathcal{W}_c}$ , is trained in an adversarial scheme with the non-saturating GAN loss [13] and $R_{1}$ regularization [26], the loss of adversarial learning process can be written as below:", + "bbox": [ + 499, + 416, + 892, + 514 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {L} _ {\\mathrm {a d v}} ^ {\\mathcal {D} \\mathcal {W} _ {c}} = - \\mathbb {E} [ \\log \\mathcal {D} _ {\\mathcal {W} _ {c}} (w _ {c}) ] - \\mathbb {E} [ \\log (1 - \\mathcal {D} _ {\\mathcal {W} _ {c}} (w _ {i})) ] (2) \\\\ + \\frac {\\gamma}{2} \\mathbb {E} \\left[ \\| \\nabla \\mathcal {D} _ {\\mathcal {W} _ {c}} \\left(w _ {c}\\right) \\| _ {2} \\right], \\\\ \\mathcal {L} _ {\\mathrm {a d v}} ^ {E} = - \\mathbb {E} \\left[ \\log \\mathcal {D} _ {\\mathcal {W} _ {c}} \\left(w _ {i}\\right) \\right], (3) \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 510, + 524, + 890, + 603 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\gamma$ is the weight of $R_{1}$ regularization, the $\\mathcal{L}_{\\mathrm{adv}}^{\\mathcal{D}_{\\mathcal{W}_c}}$ and $\\mathcal{L}_{\\mathrm{adv}}^{E}$ are the loss for the latent discriminator $\\mathcal{D}_{\\mathcal{W}_c}$ and encoder respectively. $\\mathcal{D}_{\\mathcal{W}_c}$ operates on $w_{c}$ and each entry $w_{i}$ of $w^{+}$ .", + "bbox": [ + 499, + 611, + 890, + 667 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "As discussed in Sec. 3.1, the background depth of an integrated face should be limited in a range. To estimate the background depth, we first random sample 0.1 million front images with the canonical pose condition, then we obtain the depth maps and background regions of these images. We use the parsing method [52] to get a binary mask $M$ where $M = 1$ indicates the background region and 0 otherwise. Finally, we calculate the average depth $D_{avg}$ of background regions of these samples, and we set the $D_{avg}$ as a regularization to constrain the background depth during inversion, the background regularization can be written as below:", + "bbox": [ + 497, + 669, + 890, + 834 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {B G} = \\left\\| D \\odot M - D _ {\\text {a v g}} \\odot M \\right\\| _ {2}. \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 578, + 851, + 890, + 866 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "2440", + "bbox": [ + 468, + 885, + 500, + 897 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/27ea64ea00de07ed3c1a11bf130ff831174d290515212f0bdfb90d8307e367ab.jpg", + "image_caption": [ + "Figure 4: Overview of our method. Our framework could be divided into two parts. (1) $\\mathcal{W}$ space inversion. We design an encoder $E$ to invert input image $I$ into $w^{+}$ latent codes. The $w^{+}$ latent codes are fed into a pre-trained EG3D generator $G$ to get tri-plane $_{w^{+}}$ and rendered into reconstruction image $I_{w^{+}}$ . (2) Complement the $\\mathcal{F}$ space. We calculate the image residual $\\Delta I$ between the input image and its reconstruction and propose AFA module to refine the F latent maps. The modified latent maps $F^{*}$ are transformed into tri-plane $_{mix}$ by occlusion-aware mix and rendered into the fine detailed inversion image $I_{F^{*}}$ ." + ], + "image_footnote": [], + "bbox": [ + 144, + 108, + 830, + 294 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Here, $D$ and $M$ are the depth map and background mask inverted image under the front-view pose.", + "bbox": [ + 75, + 375, + 468, + 402 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In addition, we use reconstruction loss function $\\mathcal{L}_{rec}$ follow pSp [35] in the training stage. The $\\mathcal{L}_{rec}$ is composed by pixel-wise $\\mathcal{L}_2$ loss, perceptual loss $\\mathcal{L}_{LPIPS}$ [50], and facial identity similarity loss $\\mathcal{L}_{ID}$ with pre-trained ArcFace network [9]:", + "bbox": [ + 75, + 403, + 468, + 472 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {r e c} = \\left\\| I _ {w ^ {+}} - I \\right\\| _ {2} + \\mathcal {L} _ {L P I P S} \\left(I _ {w ^ {+}}, I\\right) + \\mathcal {L} _ {I D} \\left(I _ {w ^ {+}}, I\\right). \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 87, + 479, + 468, + 494 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Adaptive Feature Alignment", + "text_level": 1, + "bbox": [ + 75, + 500, + 332, + 514 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "It is non-trivial to restore fine-detailed texture with only a highly compressed $w$ latent code. Thus, adjusting high-dimension feature maps in the $\\mathcal{F}$ space is natural to achieve high-fidelity inversion as mentioned in related 2D GAN inversion methods [3, 11, 45]. Moreover, it is worth noting that the feature maps $F$ generated with our inverted $w^{+}$ are in the canonical feature space $\\mathcal{F}_c$ .", + "bbox": [ + 75, + 520, + 468, + 617 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We calculate the residual $\\Delta I$ between $I$ and $I_{w^{+}}$ and hope to refine the feature maps to eliminate this residual. However, directly setting the residual as input and predicting the refined feature maps with a CNN to modify $F$ is invalid. This is because the residual is highly entangled with the view of the input image, while $F$ is in $\\mathcal{F}_c$ . When the view is not canonical, the refined feature maps with this residual can not project to the $\\mathcal{F}_c$ space simply. Thus, aligning the residual feature maps to the $\\mathcal{F}_c$ space is necessary to synthesize high-quality images, as mentioned in Sec. 3.2.", + "bbox": [ + 75, + 617, + 468, + 755 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "According to the above analysis, we propose an adaptive feature alignment (AFA) module that enables automatic canonical space alignment by cross-attention mechanism, as shown in Fig 5. First, we use a CNN to capture the feature $F_{\\Delta I}$ of $\\Delta I$ , and we take $F_{\\Delta I}$ as the key $K$ , value $V$ , and the feature map $F$ as a query $Q$ . Then, we utilize cross-attention modules to align the $F_{\\Delta I}$ with $F$ and output a feature $F_{\\text{align}}$ . Since the $F$ is already in the canonical feature", + "bbox": [ + 75, + 756, + 468, + 866 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/2dbb1e67ed2d33a6228061091285998fc37361098f40d10f876460efa53932b4.jpg", + "image_caption": [ + "Figure 5: The Architecture of AFA Module. We use a CNN to capture the feature $F_{\\Delta I}$ of residual image $\\Delta I$ , and align the $F_{\\Delta I}$ to $F$ with cross attention module. Finally, we refine the $F$ with the aligned feature $F_{\\text{align}}$ ." + ], + "image_footnote": [], + "bbox": [ + 502, + 375, + 889, + 458 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "space $\\mathcal{F}_c$ , and the feature $F_{align}$ can also have the properties of $\\mathcal{F}_c$ space. Finally, we use the $F_{align}$ to predict the scale map $\\gamma$ and translation map $\\beta$ to refine the $F$ with Feature-wise Linear Modulation (FiLM) [34]. The whole process of our AFA module can be formulated as follows:", + "bbox": [ + 497, + 527, + 890, + 595 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nF _ {\\Delta I} = C N N (\\Delta I),\n$$\n", + "text_format": "latex", + "bbox": [ + 559, + 603, + 699, + 619 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nQ, K, V = W _ {Q} F, W _ {K} F _ {\\Delta I}, W _ {V} F _ {\\Delta I},\n$$\n", + "text_format": "latex", + "bbox": [ + 559, + 621, + 811, + 636 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nF _ {\\text {a l i g n}} = \\text {A t t e n t i o n} (Q, K, V), \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 559, + 638, + 890, + 654 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\gamma , \\beta = C o n v _ {\\gamma} (F _ {a l i g n}), C o n v _ {\\beta} (F _ {a l i g n}),\n$$\n", + "text_format": "latex", + "bbox": [ + 559, + 655, + 828, + 671 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nF ^ {*} = \\gamma \\odot F + \\beta ,\n$$\n", + "text_format": "latex", + "bbox": [ + 561, + 673, + 685, + 688 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $W_{Q}, W_{K}, W_{V}$ are learnable projection heads and $d$ is the dimension of feature, the $F^{*}$ is the final output of our AFA module. With this adaptive alignment, we achieve a detailed complement of $\\mathcal{F}_c$ space. Note that we adopt $\\mathcal{L}_{total}$ and a $\\mathcal{L}_2$ regularization loss on $\\Delta F = F^{*} - F$ when training the AFA module.", + "bbox": [ + 497, + 698, + 890, + 780 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.3. Occlusion-aware Mix Tri-plane", + "text_level": 1, + "bbox": [ + 497, + 789, + 774, + 804 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The image residual $\\Delta I$ only contains information in the visible area of the input view. Using single-view residuals to modify the entire $F$ will lead to distortion at the occlusion region. To solve this problem, we propose the Occlusion-", + "bbox": [ + 497, + 809, + 890, + 866 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "2441", + "bbox": [ + 468, + 885, + 500, + 897 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "aware Mix Tri-plane.", + "bbox": [ + 75, + 125, + 218, + 138 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The tri-plane contains all points in the 3D space which are divided into visible points set and occlusion points set according to the input view. Here, we define the 3D points viewed in the input image in tri-plane as the visible points set $\\mathcal{V}_{(x,y,z)}$ , points in the occlusion regions as occlusion points set $\\mathcal{O}_{(x,y,z)}$ . We can get the depth map $D$ under the input view, and the two points set can be defined by:", + "bbox": [ + 75, + 138, + 468, + 229 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {V} _ {(x, y, z)} = \\left\\{\\left[ x, y, z \\right] ^ {T}: \\left[ x, y, z \\right] ^ {T} = \\pi D (u, v) \\mathcal {K} ^ {- 1} \\left[ u, v, 1 \\right] ^ {T} \\right\\}, \\\\ \\mathcal {O} _ {(x, y, z)} = \\mathbb {R} ^ {3} \\backslash \\mathcal {V} _ {(x, y, z)}, \\tag {7} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 87, + 238, + 468, + 281 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $[u,v,1]$ is the pixel homogeneous coordinate of the input image, $\\pi$ is the extrinsic camera parameter matrix of the input view, $D(u,v)$ is the depth of pixel $[u,v]$ , $\\mathcal{K}$ is the intrinsic camera parameter matrix.", + "bbox": [ + 75, + 283, + 468, + 337 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "After determining the visible area, we can supplement the refined details of the input view to the tri-plane. We define the occlusion-aware mix tri-plane as follows:", + "bbox": [ + 75, + 339, + 468, + 378 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\operatorname {t r i - p l a n e} _ {w ^ {+}} = G \\left(w ^ {+}\\right), \\\\ \\operatorname {t r i - p l a n e} _ {F ^ {*}} = G \\left(F ^ {*}\\right), (8) \\\\ \\left. \\operatorname {t r i - p l a n e} _ {\\text {m i x}} = \\operatorname {t r i - p l a n e} _ {F ^ {*}} \\right| _ {(x, y, z) \\in \\mathcal {V}} (6) \\\\ + \\operatorname {t r i - p l a n e} _ {w +} | _ {(x, y, z) \\in \\mathcal {O}}, \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 142, + 390, + 468, + 459 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $w^{+}$ is the latent code learned from the encoder, and $F^{*}$ is the refined feature map. Finally, we use tri-planes mix with rendering decoder to synthesize images under different views when inference.", + "bbox": [ + 75, + 470, + 468, + 524 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.4. Editing", + "text_level": 1, + "bbox": [ + 75, + 536, + 171, + 549 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To achieve 3D-consistent editing, we need to modify both $w^{+}$ and $F^{*}$ . We first get the edited latent code $\\hat{w}^{+}$ through classic latent code editing methods [33, 37]. Then for $F^{*}$ , we follow FS [48] to extract the features $F^{\\hat{w}^{+}}$ and $F^{w}$ from the generator convolution layer with input $\\hat{w}^{+}$ and $w$ , respectively. Finally, we calculate the difference between these two features and add it to the $F^{*}$ to get the edited features $\\hat{F^{*}}$ :", + "bbox": [ + 75, + 557, + 468, + 668 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {F} ^ {*} = F ^ {*} + F ^ {\\hat {w} ^ {+}} - F ^ {w}. \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 189, + 680, + 468, + 695 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "With the modified $\\hat{w}^{+}$ and $\\hat{F}^{*}$ , we use the method in section 4.3 to get edited mix tri-plane, and use rendering decoder to synthesize 3D-consistent edited images.", + "bbox": [ + 75, + 710, + 468, + 752 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.5. Losses.", + "text_level": 1, + "bbox": [ + 75, + 762, + 166, + 776 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In the first training stage, we use the loss function mentioned in Sec 4.1. For the input view reconstruction, the loss $\\mathcal{L}_{rec}$ is computed by:", + "bbox": [ + 75, + 783, + 468, + 826 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {r e c} = \\lambda_ {1} \\| I _ {w ^ {+}} - I \\| _ {2} + \\lambda_ {2} \\mathcal {L} _ {L P I P S} \\left(I _ {w ^ {+}}, I\\right) + \\lambda_ {3} \\mathcal {L} _ {I D} \\left(I _ {w ^ {+}}, I\\right), \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 77, + 838, + 467, + 866 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $\\lambda_{1} = 1.0, \\lambda_{2} = 0.8, \\lambda_{3} = 0.25$ . The total loss for training our encoder and the canonical latent discriminator can be written as:", + "bbox": [ + 497, + 125, + 890, + 166 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {t o t a l}} ^ {E} = \\mathcal {L} _ {\\mathrm {a d v}} ^ {\\mathcal {D} w _ {c}} + \\lambda_ {4} \\mathcal {L} _ {\\mathrm {a d v}} ^ {E} + \\lambda_ {5} \\mathcal {L} _ {B G} + \\mathcal {L} _ {\\text {r e c}}, \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 532, + 172, + 890, + 188 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $R_{1}$ regularization weight $\\gamma = 10$ , $\\lambda_4 = 0.05$ , $\\lambda_5 = 5.0$ . Moreover, we apply regularization on $\\Delta w^{+} = (w_{1} - w_{0}, w_{2} - w_{0}, \\dots, w_{13} - w_{0})$ by $\\mathcal{L}_2$ norm, i.e. $\\mathcal{L}_{w^+} = \\lambda_6\\| \\Delta w^+\\|_2$ , where $\\lambda_6 = 0.001$ .", + "bbox": [ + 497, + 194, + 890, + 250 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Once the loss in the first stage is converged, we freeze the encoder parameters and drop the canonical latent discriminator and losses $\\mathcal{L}_{\\mathrm{adv}}^{\\mathcal{D}_{\\mathcal{W}_c}},\\mathcal{L}_{\\mathrm{adv}}^E,\\mathcal{L}_{w^+}$ , but add a $\\mathcal{L}_2$ regularization on $\\Delta F = F^{*} - F$ with $\\lambda_7 = 0.0001$ for training the AFA module, i.e. $\\mathcal{L}_{\\Delta F} = \\lambda_7\\| \\Delta F\\| _2$ . We apply the loss settings to both human data and cat data.", + "bbox": [ + 497, + 250, + 890, + 334 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "For re-implemented pSp [35] and e4e [42], we train it with the same loss weight in our settings, and train them until the losses converge.", + "bbox": [ + 497, + 334, + 890, + 375 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 499, + 385, + 631, + 402 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Experiment setup. We evaluate our method on human faces and cat faces. For human faces, we use FFHQ [1] dataset for training, and CelebA-HQ [18] and MEAD [44] for evaluation. For the cat faces, we use AFHQ-CAT [7] for training and evaluation. In addition, we employ the pretrained EG3D generator and obtain the corresponding camera parameters of each image following the official implementation in EG3D.", + "bbox": [ + 497, + 409, + 890, + 517 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Baselines. We compare our method with encoder (IDE-3D [40]) and optimization-based (PTI [36] and Pose Opt. [21]) baselines in these two aspects. Moreover, we build two encoder baselines imitating the state-of-the-art StyleGAN inverters, pSp [35] and e4e [42], and present the model structure in the supplementary.", + "bbox": [ + 497, + 519, + 890, + 603 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Qualitative analysis", + "text_level": 1, + "bbox": [ + 499, + 609, + 687, + 624 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Source View Inversion Results. Fig. 6 shows the inversion performance comparison between ours and other methods. Our method's hair details and facial similarity are obviously competitive with optimization methods and surpass all the encoder-based methods.", + "bbox": [ + 497, + 630, + 890, + 698 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Novel View Synthesis Results. The comparison results are shown in Fig. 6. Inspecting the eye gaze direction and person's identity preservation when changing to novel views can reveal the differences. It can be seen that on some extreme side-face camera poses, some optimization methods produce artifacts and geometry distortions. Our method can keep synthesizing 3D-consistent images faithful to the person's identity in the input.", + "bbox": [ + 497, + 699, + 890, + 809 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.2.Quantitative analysis", + "text_level": 1, + "bbox": [ + 499, + 817, + 697, + 831 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We calculate the mean square error (MSE), LPIPS [50], and FID [16] between the source image and its inversion.", + "bbox": [ + 499, + 838, + 890, + 866 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "2442", + "bbox": [ + 468, + 885, + 500, + 897 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/e2aedef42d3dfd5ad3f27e244d833b216f9797f8614bd06b88fc97cd5145c3ef.jpg", + "image_caption": [ + "Figure 6: Visual comparison of inversion and novel-view synthesized results between our method and others. Our method surpasses all the encoder-based methods and is competitive with optimization methods in recovering texture details, i.e., our method prevents the eye orientation from changing with the camera view and artifacts in the novel view." + ], + "image_footnote": [], + "bbox": [ + 119, + 122, + 848, + 433 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/7ed9ca1a0815559e447bb0cdb84a25c49b0aff9b13e6e89f242325dd778c6b33.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
CategoryMethodReconstruction QualityNovel View Quality
Input Viewyaw=±60°yaw=0°
MSE ↓LPIPS ↓FID ↓ID ↑Geo. Err. ↓Time (s) ↓LPIPS ↓FID ↓ID ↑Geo. Err. ↓LPIPS ↓FID ↓ID ↑Geo. Err. ↓
OptimizationPTI [36]0.01630.091818.00.84170.0850115.20.292669.80.6210.14810.192553.50.7180.1006
Pose Opt. [21]0.01640.087917.50.83900.0759219.70.44771320.3210.17630.243660.20.6050.1504
Encoder-basedIDE-3D [40]0.10560.280643.60.71940.18350.06590.331779.00.5050.29140.307463.70.5130.2528
pSp-3D [35]0.07260.208231.20.78170.18460.12840.322365.70.5910.12870.313265.20.6710.1789
e4e-3D [42]0.08080.228133.00.73590.11610.13030.249557.70.5880.12690.239453.80.6530.1305
Ours-w+0.06970.198130.90.78730.11000.09630.230352.20.6550.09430.237254.10.6850.0955
Ours0.03010.125720.50.87520.09870.22620.219250.90.7000.09500.220451.70.7430.0944
", + "bbox": [ + 80, + 492, + 892, + 614 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 1: Comparison with state-of-the-art methods on inversion performance. The numbers in bold are the best performance of the optimization and encoder-based methods, respectively. Metrics of Reconstruction Quality are calculated under the input view. Metrics of Novel View Quality are the average of multi-view. The yaw angle is the source view angle.", + "bbox": [ + 75, + 623, + 894, + 668 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We adopt a pre-trained face key point detector parsenet [52] to calculate the identity similarity. To measure the geometry properties, we followed [5, 38], utilizing a pre-trained 3D face reconstruction model to extract a \"pseudo\" ground truth depth map from the source image. Then, we obtain the depth of inversion and normalize all depth maps to zero means and unit variance to calculate geometry error (Geo. Err.) by using average $\\mathcal{L}_2$ distance.", + "bbox": [ + 75, + 688, + 470, + 802 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Source View Inversion Results. Table 1 presents the quantitative comparison of the input view image reconstruction on CelebA-HQ test dataset. Our method is two orders of magnitude faster than the optimized methods with similar", + "bbox": [ + 75, + 809, + 472, + 866 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "performance, which is notably better than other encoder-based methods.", + "bbox": [ + 497, + 688, + 890, + 717 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Novel View Synthesis Results. In order to measure the multi-view consistency and the synthesized quality, we evaluate our method and baselines with a multi-view dataset, MEAD [44]. Each person in MEAD has five images with increasing yaw angles. We select one angle as the input view, invert the input image and synthesize the other four novel views. Then we use the same metrics to calculate the difference between the synthesized images and the ground truth. The quantitative comparison between the novel view synthesized results and the ground truth in dif", + "bbox": [ + 497, + 726, + 892, + 866 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "2443", + "bbox": [ + 468, + 885, + 500, + 897 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/afc3c8a45e15f98589850b01d19d5a8f464c0808a207e00edd3903f4754095cb.jpg", + "image_caption": [ + "Figure 7: Ablation of Geometry-aware Encoder. All images are synthesized only with $w^{+}$ . Without both modules, $w^{+}$ fails to generate integrated 3D geometry and texture. The $L_{BG}$ helps distinguish foreground and background. With $\\mathcal{D}_{\\mathcal{W}_c}$ , we can get good inversion under the input view but fail under the novel view. With both modules, $w^{+}$ can obtain an integrated side face of the woman, which is occlusion under the input view." + ], + "image_footnote": [], + "bbox": [ + 80, + 125, + 467, + 305 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "ferent views is shown in Table 1. Our method shows similar performance with PTI when the input image is a front face $(\\mathrm{yaw} = 0^{\\circ})$ . When inverting side faces, the difficulty of inversion increases drastically when the yaw angle increases. We calculated the metrics of the largest yaw angle in MEAD $(\\mathrm{yaw} = \\pm 60^{\\circ})$ , and our model has robust performance when the test yaw angle varies. However, the performance of optimization methods degrades remarkably at an extreme angle.", + "bbox": [ + 75, + 442, + 468, + 553 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.3. Ablation Analysis", + "text_level": 1, + "bbox": [ + 75, + 565, + 250, + 579 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We present ablation studies with qualitative analysis of our proposed method below, and the corresponding numerical ablation results are in our supplementary.", + "bbox": [ + 75, + 587, + 468, + 628 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Geometry-aware Encoder. We conduct ablation experiments and make qualitative comparisons to verify that our proposed canonical latent discriminator $(\\mathcal{D}_{\\mathcal{W}_c})$ and background regularization $(\\mathcal{L}_{BG})$ contribute to restoring 3D geometry. Generally, recovering the geometry from a side face input is more challenging and we test such a case. As shown in Fig. 7, only if we adopt the canonical discriminator and the background regularization could we obtain a satisfactory foreground and background geometry.", + "bbox": [ + 75, + 629, + 468, + 754 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Adaptive Feature Alignment. We proposed Adaptive Feature Alignment (AFA) to refine the $F$ latent map and add texture details from the source view. Fig. 8 demonstrates that we can recover more details with AFA.", + "bbox": [ + 75, + 754, + 468, + 809 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Occlusion-aware Mix Tri-plane. To verify the necessity of our proposed occlusion-aware mix tri-plane, we ablate this operation and visualize the novel view results in Fig. 9. The occlusion map shows the spatial position of surface points", + "bbox": [ + 75, + 809, + 468, + 866 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/02bd75f9518dbefc9cff5c37265c55a26824a8b6103f1a00864d81db79de6410.jpg", + "image_caption": [ + "Figure 8: Ablation of Adaptive Feature Alignment. We replace AFA with a CNN network and obtain the results. Without feature alignment, it is difficult to reconstruct the hair and facial details." + ], + "image_footnote": [], + "bbox": [ + 502, + 124, + 695, + 178 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/7adb34605baa08408b4fc2ea44bd3c6b22a1997e5a1bd72712d05fc7125d63f5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 697, + 124, + 889, + 176 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/bd1412f2e7b937d752ef20e257b2b0a8f83c0ed011341d344c2e8dc0ad8182e6.jpg", + "image_caption": [ + "Figure 9: Ablation of Occlusion-aware mix tri-plane. We visualize the occlusion regions $\\mathcal{O}_{(x,y,z)}$ of the input view in the last column (black points). The green arrow points out $\\mathcal{O}_{(x,y,z)}$ in the novel view, and it is obvious that the occlusion-aware mix tri-plane can avoid artifacts." + ], + "image_footnote": [], + "bbox": [ + 502, + 241, + 890, + 388 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/c1f26b2e765a19c8c7b24a1e0582fe0bcbc967fa3d287666524b2c8a77e89703.jpg", + "image_caption": [ + "Figure 10: Editing result under novel views. We add three different attributes to three faces. Our method generates both realistic editing and 3D-consistent novel views." + ], + "image_footnote": [], + "bbox": [ + 502, + 467, + 890, + 676 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "in ray sampling, the visible region in the original view is white, and the occlusion region is black. Without the mix tri-plane, the occlusion area from the source view is easy to produce artifacts in novel views.", + "bbox": [ + 497, + 739, + 890, + 794 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4. Image Editing Results", + "text_level": 1, + "bbox": [ + 499, + 802, + 705, + 817 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In GAN inversion-based image manipulation, the editability and the reconstruction trade-off widely exists in both 2D and 3D scenarios. We validate the editing method", + "bbox": [ + 497, + 824, + 890, + 866 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "2444", + "bbox": [ + 468, + 885, + 500, + 897 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/dd3ce5e5ff80b88a81039421bb32462b9379d2ceb475a8b1590846ef195aa0ee.jpg", + "image_caption": [ + "Figure 11: Results of our encoder in other 3D GANs." + ], + "image_footnote": [], + "bbox": [ + 77, + 122, + 894, + 261 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/d5923d486c39afd4dda648367c316e3755cb99ab0d07da60fcec752063f7823b.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MSE ↓LPIPS ↓FID ↓MSE ↓LPIPS ↓FID ↓
w/o AFA0.05860.231713.43w/ AFA0.03670.174510.82
", + "bbox": [ + 78, + 283, + 467, + 311 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 2: Ablation of AFA on ShapeNet Cars.", + "bbox": [ + 115, + 314, + 430, + 328 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "mentioned in Sec. 4.4 and display the multi-view edited results in Fig. 10. We choose three different edit directions, 'Young' to reduce person's age, 'Unhappy' to change emotion, and 'Glasses' to add accessories. It is noticeable that our method not only restores the geometric and texture information of the input image but also ensures the editing consistency of multi-view. The edited results demonstrate that our inversion method can be well applied to the facial image editing tasks.", + "bbox": [ + 75, + 342, + 468, + 467 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/6b816134e4a44946b9b5ed091e2151b5ae6970cbc52852231505cebbc2bab88b.jpg", + "image_caption": [ + "Figure 12: (a) Tri-plane canonical feature space. (b) Results of our method on ShapeNet Cars datasets. Best viewed zoomed in and in color." + ], + "image_footnote": [], + "bbox": [ + 142, + 478, + 411, + 676 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Generalization", + "text_level": 1, + "bbox": [ + 75, + 739, + 226, + 754 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Our method can be adapted to other 3D GANs (e.g., EpiGRAF [39] and StyleSDF [32]) and it works also with categories where pose estimation and canonicalization are more difficult (e.g., Shapenet cars).", + "bbox": [ + 75, + 762, + 468, + 819 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Extension to other 3D GANs. We choose EG3D as our base 3D GAN due to its superior performance, but our method can also be applied to other 3D GANs. The canon-", + "bbox": [ + 75, + 824, + 470, + 866 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "ical space, which plays a vital role in 3D GAN inversion, is commonly presented in the latent space (i.e., $w^{+}$ space) of 3D GANs. By inverting images into the canonical space, we preserve geometry and achieve high-fidelity reconstruction, as demonstrated in our experiments on EpiGRAF [39] and StyleSDF [32] in Fig. 11. The results of w/o $\\mathcal{D}_{\\mathcal{W}_c}, L_{BG}$ mean that we only use the base encoder without the canonical latent discriminator and the background depth regularization. In contrast, w/ $\\mathcal{D}_{\\mathcal{W}_c}, L_{BG}$ is our full encoder model. The noticeable performance gap proves the powerful inversion ability of our method. Our method explores the canonical space's characteristics, ensuring distortion-free shape generation and exceptional performance in image 3D inversion.", + "bbox": [ + 497, + 286, + 890, + 480 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Extension to ShapeNet Cars. Fig. 12 shows (a) the canonical space and (b) the inversion results on ShapeNet Cars. Even without identity loss, our method can achieve good performance(see the Col.3,5 of (b)). As the tri-plane is canonical, without the AFA module, the residual feature can not align with the canonical feature space (see the Col. 2,4 of (b) and Table 2).", + "bbox": [ + 497, + 486, + 892, + 583 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "7. Conclusion", + "text_level": 1, + "bbox": [ + 499, + 585, + 618, + 599 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this work, we explore the inherent property of EG3D's latent space and find that the key to achieve high-quality shape and texture inversion is inverting input images to the canonical space. In light of this, we design an efficient geometry-aware encoder with an adaptive feature alignment module and demonstrate their effectiveness. Besides, we propose an occlusion-aware mix tri-plane to avoid invisible region distortion in novel views. Extensive experiments demonstrate that our method has competitive inversion performance with optimization-based methods, but operates two orders of magnitude faster. In addition, our method is demonstrated to be a powerful tool for realistic and 3D view-consistent editing of facial images.", + "bbox": [ + 497, + 602, + 890, + 781 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "8. Acknowledgement", + "text_level": 1, + "bbox": [ + 499, + 783, + 680, + 798 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work was supported by the National Key R&D Program of China (2022YFB4701400/4701402), SZSTC Grant (JCYJ20190809172201639, WDZC20200820200655001), Shenzhen Key Laboratory (ZDSYS20210623092001004), and Beijing Key Lab of Networked Multimedia.", + "bbox": [ + 497, + 796, + 890, + 866 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "2445", + "bbox": [ + 468, + 885, + 500, + 897 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 124, + 171, + 138 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Rameen Abdul, Yipeng Qin, and Peter Wonka. Image2stylegan: How to embed images into the stylegan latent space? In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4432-4441, 2019. 3, 6", + "[2] Yuval Alaluf, Or Patashnik, and Daniel Cohen-Or. Restyle: A residual-based stylegan encoder via iterative refinement. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6711–6720, 2021. 3", + "[3] Yuval Alaluf, Omer Tov, Ron Mokady, Rinon Gal, and Amit Bermano. Hyperstyle: Stylegan inversion with hypernetworks for real image editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18511-18521, 2022. 2, 5", + "[4] Lucy Chai, Jun-Yan Zhu, Eli Shechtman, Phillip Isola, and Richard Zhang. Ensembling with deep generative views. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14997-15007, 2021. 3", + "[5] Eric R Chan, Connor Z Lin, Matthew A Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas J Guibas, Jonathan Tremblay, Sameh Khamis, et al. Efficient geometry-aware 3d generative adversarial networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 16123-16133, 2022. 1, 2, 7", + "[6] Eric R Chan, Marco Monteiro, Petr Kellnhofer, Jiajun Wu, and Gordon Wetzstein. pi-gan: Periodic implicit generative adversarial networks for 3d-aware image synthesis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5799-5809, 2021. 1, 2", + "[7] Yunjoy Choi, Youngjung Uh, Jaejun Yoo, and Jung-Woo Ha. Stargan v2: Diverse image synthesis for multiple domains. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8188-8197, 2020. 6", + "[8] Edo Collins, Raja Bala, Bob Price, and Sabine Susstrunk. Editing in style: Uncovering the local semantics of gans. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5771-5780, 2020. 3", + "[9] Jiankang Deng, Jia Guo, Niannan Xue, and Stefanos Zafeiriou. Arcface: Additive angular margin loss for deep face recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4690-4699, 2019. 5", + "[10] Yu Deng, Jiaolong Yang, Jianfeng Xiang, and Xin Tong. Gram: Generative radiance manifolds for 3d-aware image generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10673-10683, 2022. 2", + "[11] Tan M Dinh, Anh Tuan Tran, Rang Nguyen, and Binh-Son Hua. Hyperinverter: Improving stylegan inversion via hypernetwork. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11389-11398, 2022. 2, 5", + "[12] Shubham Goel, Angjoo Kanazawa, and Jitendra Malik. Shape and viewpoint without keypoints. In European Conference on Computer Vision, 2020. 2", + "[13] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and" + ], + "bbox": [ + 78, + 147, + 470, + 866 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Yoshua Bengio. Generative adversarial nets. In Advances in Neural Information Processing Systems, 2014. 2, 4", + "[14] Jiatao Gu, Lingjie Liu, Peng Wang, and Christian Theobalt. Stylenerf: A style-based 3d-aware generator for high-resolution image synthesis. arXiv preprint arXiv:2110.08985, 2021. 1, 2", + "[15] Paul Henderson, Vagia Tsiminaki, and Christoph H Lampert. Leveraging 2d data to learn textured 3d mesh generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. 2", + "[16] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in Neural Information Processing Systems, 30, 2017. 6", + "[17] Angjoo Kanazawa, Shubham Tulsiani, Alexei A. Efros, and Jitendra Malik. Learning category-specific mesh reconstruction from image collections. In European Conference on Computer Vision, 2018. 2", + "[18] Tero Karras, Timo Aila, Samuli Laine, and Jaakko Lehtinen. Progressive growing of GANs for improved quality, stability, and variation. In International Conference On Learning Representations, 2018. 6", + "[19] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2019. 2", + "[20] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of StyleGAN. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2020. 2", + "[21] Jaehoon Ko, Kyusun Cho, Daewon Choi, Kwangrok Ryoo, and Seungryong Kim. 3d gan inversion with pose optimization. arXiv preprint arXiv:2210.07301, 2022. 1, 3, 6, 7", + "[22] Yushi Lan, Xuyi Meng, Shuai Yang, Chen Change Loy, and Bo Dai. Self-supervised geometry-aware encoder for style-based 3d gan inversion. arXiv preprint arXiv:2212.07409, 2022. 2, 3", + "[23] Yu-Jhe Li, Tao Xu, Bichen Wu, Ningyuan Zheng, Xiaoliang Dai, Albert Pumarola, Peizhao Zhang, Peter Vajda, and Kris Kitani. 3d-aware encoding for style-based neural radiance fields. arXiv preprint arXiv:2211.06583, 2022. 2, 3", + "[24] Hongyu Liu, Yibing Song, and Qifeng Chen. Delving stylegan inversion for image editing: A foundation latent space viewpoint. arXiv preprint arXiv:2211.11448, 2022. 2", + "[25] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10012-10022, 2021. 4", + "[26] Lars Mescheder, Andreas Geiger, and Sebastian Nowozin. Which training methods for gans do actually converge? In International Conference on Machine Learning, pages 3481-3490. PMLR, 2018. 4", + "[27] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf:" + ], + "bbox": [ + 502, + 125, + 890, + 866 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "2446", + "bbox": [ + 468, + 887, + 500, + 897 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Representing scenes as neural radiance fields for view synthesis. In European Conference on Computer Vision, 2020. 1, 2, 3", + "[28] Thu Nguyen-Phuoc, Chuan Li, Lucas Theis, Christian Richardt, and Yong-Liang Yang. Hologan: Unsupervised learning of 3d representations from natural images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7588-7597, 2019. 2", + "[29] Thu H Nguyen-Phuoc, Christian Richardt, Long Mai, Yongliang Yang, and Niloy Mitra. Blockgan: Learning 3d object-aware scene representations from unlabelled images. Advances in Neural Information Processing Systems, 33:6767-6778, 2020. 2", + "[30] Michael Niemeyer and Andreas Geiger. Giraffe: Representing scenes as compositional generative neural feature fields. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11453-11464, 2021. 2", + "[31] Yotam Nitzan, Amit Bermano, Yangyan Li, and Daniel Cohen-Or. Face identity disentanglement via latent space mapping. arXiv preprint arXiv:2005.07728, 2020. 4", + "[32] Roy Or-El, Xuan Luo, Mengyi Shan, Eli Shechtman, Jeong Joon Park, and Ira Kemelmacher-Shlizerman. Stylesdf: High-resolution 3d-consistent image and geometry generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13503–13513, 2022. 1, 2, 9", + "[33] Or Patashnik, Zongze Wu, Eli Shechtman, Daniel Cohen-Or, and Dani Lischinski. Styleclip: Text-driven manipulation of stylegan imagery. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2085–2094, 2021. 3, 6", + "[34] Ethan Perez, Florian Strub, Harm De Vries, Vincent Dumoulin, and Aaron Courville. Film: Visual reasoning with a general conditioning layer. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 32, 2018. 5", + "[35] Elad Richardson, Yuval Alaluf, Or Patashnik, Yotam Nitzan, Yaniv Azar, Stav Shapiro, and Daniel Cohen-Or. Encoding in style: a stylegan encoder for image-to-image translation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2287–2296, 2021. 3, 4, 5, 6, 7", + "[36] Daniel Roich, Ron Mokady, Amit H Bermano, and Daniel Cohen-Or. Pivotal tuning for latent-based editing of real images. ACM Transactions on Graphics (TOG), 42(1):1-13, 2022. 3, 6, 7", + "[37] Yujun Shen, Jinjin Gu, Xiaou Tang, and Bolei Zhou. Interpreting the latent space of gans for semantic face editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9243-9252, 2020. 3, 6", + "[38] Yichun Shi, Divyansh Aggarwal, and Anil K Jain. Lifting 2d stylegan for 3d-aware face generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6258-6266, 2021. 7", + "[39] Ivan Skorokhodov, Sergey Tulyakov, Yiqun Wang, and Peter Wonka. Epigraph: Rethinking training of 3d gans. arXiv preprint arXiv:2206.10535, 2022. 9" + ], + "bbox": [ + 78, + 125, + 468, + 865 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[40] Jingxiang Sun, Xuan Wang, Yichun Shi, Lizhen Wang, Jue Wang, and Yebin Liu. Ide-3d: Interactive disentangled editing for high-resolution 3d-aware portrait synthesis. arXiv preprint arXiv:2205.15517, 2022. 3, 6, 7", + "[41] Maxim Tatarchenko, Alexey Dosovitskiy, and Thomas Brox. Multi-view 3D models from single images with a convolutional network. In European Conference on Computer Vision, 2016. 2", + "[42] Omer Tov, Yuval Alaluf, Yotam Nitzan, Or Patashnik, and Daniel Cohen-Or. Designing an encoder for stylegan image manipulation. ACM Transactions on Graphics (TOG), 40(4):1-14, 2021. 2, 3, 4, 6, 7", + "[43] Shubham Tulsiani, Hao Su, Leonidas J. Guibas, Alexei A. Efros, and Jitendra Malik. Learning shape abstractions by assembling volumetric primitives. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2017. 2", + "[44] Kaisiyuan Wang, Qianyi Wu, Linsen Song, Zhuoqian Yang, Wayne Wu, Chen Qian, Ran He, Yu Qiao, and Chen Change Loy. Mead: A large-scale audio-visual dataset for emotional talking-face generation. In European Conference on Computer Vision, pages 700–717. Springer, 2020. 6, 7", + "[45] Tengfei Wang, Yong Zhang, Yanbo Fan, Jue Wang, and Qifeng Chen. High-fidelity gan inversion for image attribute editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11379-11388, 2022. 2, 5", + "[46] Zongze Wu, Dani Lischinski, and Eli Shechtman. Stylespace analysis: Disentangled controls for stylegan image generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12863-12872, 2021. 3", + "[47] Jiaxin Xie, Hao Ouyang, Jingtan Piao, Chenyang Lei, and Qifeng Chen. High-fidelity 3d gan inversion by pseudomulti-view optimization. arXiv preprint arXiv:2211.15662, 2022.1.3", + "[48] Xu Yao, Alasdair Newson, Yann Gousseau, and Pierre Hellier. A style-based gan encoder for high fidelity reconstruction of images and videos. European Conference on Computer Vision, 2022. 6", + "[49] Fei Yin, Yong Zhang, Xuan Wang, Tengfei Wang, Xiaoyu Li, Yuan Gong, Yanbo Fan, Xiaodong Cun, Ying Shan, Cengiz Oztireli, et al. 3d gan inversion with facial symmetry prior. arXiv preprint arXiv:2211.16927, 2022. 1", + "[50] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 586-595, 2018. 5, 6", + "[51] Jiapeng Zhu, Yujun Shen, Deli Zhao, and Bolei Zhou. Indomain gan inversion for real image editing. In European Conference on Computer Vision, pages 592-608. Springer, 2020. 3", + "[52] zllrunning. faceParsing.pytorch. https://github.com/zllrunning/faceParsing.PyTorch/, 2019.4.7" + ], + "bbox": [ + 502, + 127, + 890, + 847 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "2447", + "bbox": [ + 468, + 887, + 500, + 897 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/d0a41b80-a701-4955-834c-d42058b2d111_model.json b/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/d0a41b80-a701-4955-834c-d42058b2d111_model.json new file mode 100644 index 0000000000000000000000000000000000000000..cf9f2c2b491539281a8ff8544c6eeb62d449c3f7 --- /dev/null +++ b/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/d0a41b80-a701-4955-834c-d42058b2d111_model.json @@ -0,0 +1,2411 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.13, + 0.051, + 0.201, + 0.085 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.254, + 0.049, + 0.79, + 0.087 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.117, + 0.145, + 0.853, + 0.187 + ], + "angle": 0, + "content": "Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding" + }, + { + "type": "text", + "bbox": [ + 0.198, + 0.212, + 0.793, + 0.229 + ], + "angle": 0, + "content": "Ziyang Yuan\\(^{1*}\\) Yiming Zhu\\(^{1,2*}\\) Yu Li\\(^{2\\dagger}\\) Hongyu Liu\\(^{3}\\) Chun Yuan\\(^{1\\dagger}\\)" + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.229, + 0.91, + 0.261 + ], + "angle": 0, + "content": "\\(^{1}\\)Tsinghua Shenzhen International Graduate School \\(^{2}\\)International Digital Economy Academy (IDEA) \\(^{3}\\)Hong Kong University of Science and Technology" + }, + { + "type": "text", + "bbox": [ + 0.377, + 0.263, + 0.62, + 0.275 + ], + "angle": 0, + "content": "https://eg3d-goae.github.io" + }, + { + "type": "image", + "bbox": [ + 0.1, + 0.291, + 0.87, + 0.502 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.513, + 0.89, + 0.542 + ], + "angle": 0, + "content": "Figure 1: The inversion and editing results of our method on human portraits and cat images. The novel view synthesized images demonstrate that our method can achieve high-quality inversion and editing given a single image input." + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.553, + 0.312, + 0.566 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.572, + 0.47, + 0.848 + ], + "angle": 0, + "content": "3D GAN inversion aims to achieve high reconstruction fidelity and reasonable 3D geometry simultaneously from a single image input. However, existing 3D GAN inversion methods rely on time-consuming optimization for each individual case. In this work, we introduce a novel encoder-based inversion framework based on EG3D, one of the most widely-used 3D GAN models. We leverage the inherent properties of EG3D's latent space to design a discriminator and a background depth regularization. This enables us to train a geometry-aware encoder capable of converting the input image into corresponding latent code. Additionally, we explore the feature space of EG3D and develop an adaptive refinement stage that improves the representation ability of features in EG3D to enhance the recovery of fine-grained textural details. Finally, we propose an occlusion-aware fusion operation to prevent distortion in unobserved regions. Our method achieves impressive results comparable to optimization-based methods while operating up to 500 times faster. Our framework is well-suited for applications such as semantic editing." + }, + { + "type": "page_footnote", + "bbox": [ + 0.101, + 0.854, + 0.351, + 0.867 + ], + "angle": 0, + "content": "* Equal contributions; † Corresponding author." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.553, + 0.631, + 0.566 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.576, + 0.892, + 0.756 + ], + "angle": 0, + "content": "Recent advances in 3D-aware generative adversarial networks (GAN) (e.g. [5, 6, 14, 32]) have integrated neural radiance fields (NeRF) [27] into style-based generation, resulting in remarkable success in generating highly realistic 3D portraits. Similar to 2D GAN inversion techniques, 3D GAN inversion also projects images into the latent space of pre-trained 3D GAN models. However, in addition to pursuing faithful image reconstruction and preserving fined details, 3D GAN inversion also aims for accurate 3D geometry, which is critical for generating realistic and consistent multi-view images. This ability to ensure the correctness of 3D geometry is a crucial advantage of 3D GAN inversion over its 2D counterpart." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.756, + 0.893, + 0.868 + ], + "angle": 0, + "content": "Some optimization-based methods, such as [21, 47, 49], first invert the image to a latent code to obtain a coarse 3D shape. They then synthesize pseudo-multi-view images with this shape using a warping process. These pseudo images are used as supervision to optimize the parameters of the 3D GAN for more precise 3D geometry and better detail preservation. While these iterative optimization-based pipelines can prevent shape collapse and produce accurate" + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.887, + 0.501, + 0.898 + ], + "angle": 0, + "content": "2437" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.127, + 0.47, + 0.168 + ], + "angle": 0, + "content": "results, the optimization process needs to be performed for each individual case, which is time-consuming and impractical for many applications." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.171, + 0.47, + 0.42 + ], + "angle": 0, + "content": "Several encoder-based methods [22, 23] leverage a pretrained 3D GAN to generate proxy data by randomly sampling latent codes and camera poses. They then employ these paired proxy data to train an encoder in a self-supervised fashion and further refine features in 3D GAN. These encoder-based techniques offer higher efficiency but lower high-fidelity reconstruction ability. Moreover, due to a domain gap between the paired proxy data and real images, the encoder may invert the in-the-wild images to unsuitable latent codes. To address this issue, we study the properties of the latent space in 3D GAN and develop a geometry-aware encoder that predicts the latent code incorporating these properties. Furthermore, since the latent code can not preserve details of input images well, we explore the characteristics of feature space in 3D GAN to help our method improve the performance in reconstructing the original appearance. The latent and feature spaces are widely discussed in 2D GAN inversion [11, 24, 42]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.422, + 0.47, + 0.782 + ], + "angle": 0, + "content": "This paper presents a novel encoder-based method for inverting 3D images generated by EG3D [5], a well-known and high-quality 3D GAN. Our approach is simple yet effective and is based on the discovery of a specific latent space within EG3D, which we call the canonical latent space \\(\\mathcal{W}_c\\). We find that latent codes belonging to this space can produce human faces with superior 3D shape and texture quality following two principles. Firstly, the input pose before the mapping network of EG3D must be a static canonical pose throughout the generation process. Secondly, the depth of the background should fall within a fixed range. Based on this, we propose using an encoder to invert the image into this canonical latent space using a proposed latent code discriminator and depth regularization. Although our encoder produces a suitable latent code that preserves the reasonable 3D shape of the input image, but the code is low dimension, making it challenging to capture texture details. To address this, similar to the 2D GAN inversion [3, 45], we refine the selected features in EG3D based on the residual between the input image and reconstruction image with predicted latent code. Meanwhile, we also find there is a canonical feature space \\(\\mathcal{F}_c\\) in EG3D, so we design an alignment module to project the refined feature to the canonical feature space. Moreover, we introduce an occlusion-aware fusion operation to avoid texture and shape distortions in reconstructing invisible regions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.784, + 0.47, + 0.868 + ], + "angle": 0, + "content": "We conduct comprehensive experiments to evaluate the efficiency and effectiveness of our method, and the results demonstrate that our method achieves high-quality inversion comparable to optimization-based methods and superior to other encoder-based methods. We also demonstrate our approach is effective in 3D-aware editing applications." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.127, + 0.894, + 0.169 + ], + "angle": 0, + "content": "See Fig. 1 for some examples of inversion and editing of human portraits and cat faces obtained by our method. Our contribution can be summarised as following:" + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.176, + 0.891, + 0.217 + ], + "angle": 0, + "content": "- We conduct an exploration on the latent space and feature space of EG3D and discover the presence of a canonical attribute." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.221, + 0.892, + 0.276 + ], + "angle": 0, + "content": "- Based on our analysis of the characteristics of the canonical latent space, we propose a geometry-aware encoder by utilizing a canonical latent discriminator and depth regularization." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.279, + 0.892, + 0.334 + ], + "angle": 0, + "content": "- We introduce an alignment module based on the canonical feature space and an occlusion-aware method to refine the selected features of the generator and supplement high-quality details." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.338, + 0.892, + 0.406 + ], + "angle": 0, + "content": "- The proposed method exhibits competitive performance with existing methods in human portraits, both qualitatively and quantitatively. Additionally, our method can also generalize to the cat faces and is effective in 3D editing tasks." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.176, + 0.892, + 0.406 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.419, + 0.642, + 0.433 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.442, + 0.835, + 0.457 + ], + "angle": 0, + "content": "2.1. Generative 3D-Aware Image Synthesis." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.463, + 0.892, + 0.573 + ], + "angle": 0, + "content": "Generative Adversarial Network [13] made significant advancements in generating both 2D photorealistic images [19, 20] and 3D-Aware consistent images. In 3D-aware image generation, some works build 3D GAN based on explicit 3D representations, such as point-cloud [41], voxel [28, 29, 43], and mesh [12, 15, 17]. However, these models often fail to generate high-resolution 3D scenes with high-quality details." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.574, + 0.892, + 0.794 + ], + "angle": 0, + "content": "Since NeRF [27] achieved outstanding multi-view image synthesis, a sequence of works has begun to use implicit 3D representation and volume rendering for 3D generation [5, 6, 10, 14, 30, 32]. Pi-GAN [6] is the first attempt at using GAN to generate NeRF for 3D-aware image synthesis. After that, StyleNeRF [14] proposes a view-consistent upsampling module to generate high-resolution images. StyleSDF [32] combines an SDF-based volume renderer and a 2D CNN network to obtain geometry information. GRAM [10] introduces 2D manifolds to regulate point sampling strategy in volume rendering. EG3D [5] leverages StyleGAN2 [20]'s structure and designs a computationally efficient 3D representation called tri-plane. It can synthesize high-resolution view-consistent images and produces high-quality 3D geometry. We explore EG3D's latent space and build our inversion encoder based on EG3D." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.804, + 0.655, + 0.818 + ], + "angle": 0, + "content": "2.2. GAN Inversion" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.825, + 0.892, + 0.867 + ], + "angle": 0, + "content": "GAN Inversion is an inverse process of the generation that projects the given image to corresponding latent code for faithful reconstruction from the source image. Thus," + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.887, + 0.502, + 0.898 + ], + "angle": 0, + "content": "2438" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.089, + 0.123, + 0.46, + 0.216 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.216, + 0.47, + 0.256 + ], + "angle": 0, + "content": "Figure 2: Recap of EG3D. \\( z, p \\) denotes a Gaussian sample and a pose condition. The relation of \\( w, F \\), and tri-plane is illustrated." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.284, + 0.47, + 0.45 + ], + "angle": 0, + "content": "the image editing process can be conducted by semantic editing on the latent code [33, 37, 51]. In 2D GAN, inversion methods are mainly divided into three categories. Optimization-based methods [1, 8, 46] optimize the generator's latent code or parameters both, achieve high reconstruction quality, but are time-consuming. Encoder-based methods [2, 35, 42] train an encoder to project input images to the latent codes. These methods can get faster inference than optimization-based methods but unsatisfactory inversion fidelity. Hybrid methods [4, 36, 51] use an encoder to get a latent as initialization, then optimize the latent code and generator parameters, which is still time-consuming." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.452, + 0.471, + 0.716 + ], + "angle": 0, + "content": "Unlike 2D methods, 3D GAN Inversion should also consider multi-view-consistence. Directly transferring 2D methods to the 3D inversion is prone to suffering geometry collapse and artifacts. To solve it, Pose Opt. [21] jointly optimizes camera pose, latent codes, and generator parameters. HFGI3D [47] is an optimization-based method that extracts mesh to create pseudo-multi-view supervision. Meanwhile, encoder methods are also gradually developing. IDE-3D [40] uses semantic segmentation to re-train EG3D and learns an encoder for inversion to edit images. NeRF-3DE [23] uses identity contrastive learning to train a based encoder and then trains a refining encoder for better details. E3DGE [22] trains a base encoder to learn coarse shape and texture and supplements local details with pixel-aligned features. However, existing encoder-based methods [22, 23] rely on synthetic paired data and may not generalize well to real-world scenarios. None of the state-of-the-art methods can handle time efficiency and 3D inversion quality simultaneously." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.731, + 0.26, + 0.746 + ], + "angle": 0, + "content": "3. EG3D Exploration" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.755, + 0.469, + 0.797 + ], + "angle": 0, + "content": "In this section, we first briefly review the EG3D model. Then, we explore and analyze the properties of latent space and feature space in EG3D." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.797, + 0.469, + 0.867 + ], + "angle": 0, + "content": "The pipeline of EG3D is shown in Fig 2. It first combines a Gaussian vector \\( z \\) and a pose condition \\( p \\) as input and builds a mapper to generate a latent code \\( w \\), this process can be denoted as \\( w = \\text{mapping}(z, p) \\). Then this latent code \\( w \\) will be sent to each layer of a style-based hierarchical gen" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.127, + 0.892, + 0.266 + ], + "angle": 0, + "content": "erator to obtain the feature maps \\( F \\). These feature maps are enlarged layer by layer. The last layer's feature map reshape to tri-plane, an efficient 3D representation consists of three axis-aligned feature planes \\( (F_{xy}, F_{xz}, F_{yz}) \\). With this efficient 3D representation, EG3D samples point features from the tri-plane to synthesize multi-view images or depths by a rendering decoder \\( R_{dec} \\) with volume rendering [27]. Similar to the 2D GAN, the latent code \\( w \\) belongs to a latent space \\( \\mathcal{W} \\), and all feature maps in the generator construct the \\( \\mathcal{F} \\) space." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.279, + 0.746, + 0.294 + ], + "angle": 0, + "content": "3.1. Canonical Latent Space \\(\\mathcal{W}_c\\)" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.302, + 0.892, + 0.508 + ], + "angle": 0, + "content": "In order to investigate the properties of the latent space \\(\\mathcal{W}\\) and its relationship with pose conditioning, we adopt a fixed \\(z\\) and sample various pose conditions to generate corresponding latent code \\(w\\). Fig. 3 illustrates that when \\(w\\) is conditioned on an unsuitable pose \\(p\\) far away from the canonical pose, the generated 3D shapes fail to generalize to other views synthesis. Only when the pose condition is canonical can the synthesized images maintain shape and texture consistency across multiple views. Meanwhile, we find a clear depth gap between the face and background regions when generating good results with the canonical pose condition. Under canonical pose, the depth of the background is restricted to a fixed range, while the face and background regions are confused for the other pose conditions." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.511, + 0.893, + 0.678 + ], + "angle": 0, + "content": "These observations lead us to identify a specific subspace of \\(\\mathcal{W}\\) intuitively, which we call canonical latent space, denoted as \\(\\mathcal{W}_c\\), that is responsible for ensuring reasonable 3D shape and texture across multiple views. There are two principles of this canonical latent space. Firstly, the input pose before the mapping network of EG3D must be a static canonical pose. Secondly, the depth of the background should fall within a fixed range to distinguish the face and background regions. Based on these findings, we propose that a high-quality 3D-GAN inversion method should first retrieve a \\(w\\) latent code in \\(\\mathcal{W}_c\\) to ensure the best possible image synthesis results." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.691, + 0.75, + 0.707 + ], + "angle": 0, + "content": "3.2. Canonical Feature Space \\(\\mathcal{F}_c\\)" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.714, + 0.892, + 0.867 + ], + "angle": 0, + "content": "To analyze the characteristics of \\(\\mathcal{F}\\) space, we generate the latent codes with different pose conditions to synthesize multiple tri-planes. We visualize the tri-plane as illustrated in Fig 3. The tri-plane also represents a canonical view when the pose condition is canonical (i.e., the columns \\(\\mathrm{g} \\sim \\mathrm{i}\\) in row \\(\\mathrm{L}_2\\)). It indicates that there is also a specific subspace of \\(\\mathcal{F}\\), we call it canonical feature space, denoted as \\(\\mathcal{F}_c\\), and the canonical latent space \\(\\mathcal{W}_c\\) produces the canonical feature space \\(\\mathcal{F}_c\\) with the generator layers. The \\(\\mathcal{F}_c\\) can supply sufficient facial information for rendering multi-view images." + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.887, + 0.502, + 0.898 + ], + "angle": 0, + "content": "2439" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.08, + 0.107, + 0.362, + 0.33 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.369, + 0.108, + 0.618, + 0.33 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.623, + 0.107, + 0.89, + 0.325 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.333, + 0.893, + 0.404 + ], + "angle": 0, + "content": "Figure 3: Illustration of canonical Pose condition. We synthesize multi-view images for three pose conditions \\( p \\), including left, right, and canonical. As shown in a \\( \\sim \\)c, the canonical pose condition in row \\( L_2 \\) has no distortion face shape. Moreover, depth maps in row \\( L_2 \\) demonstrate that images on the canonical pose condition have significant foreground and background differences. In contrast, flattened shape depth maps in rows \\( L_1 \\) and \\( L_3 \\) have foreground and background confusion. Columns \\( g \\sim i \\) reveal the tri-plane is also related to the pose condition." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.416, + 0.169, + 0.43 + ], + "angle": 0, + "content": "4. Method" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.439, + 0.474, + 0.633 + ], + "angle": 0, + "content": "The pipeline of our method is shown in Fig. 4. We first project the input image \\(I\\) to the latent code \\(w^{+} \\subset \\mathbb{R}^{14 \\times 512}\\) with our encoder, where \\(w^{+} = (w_{0}, w_{1}, \\dots, w_{13})\\) is an extension of latent code \\(w\\) and can preserve the details better as mentioned in 2D GAN inversion [35, 42]. Then we calculate the residual between \\(I\\) and the generated image \\(I_{w^{+}}\\) based on \\(w^{+}\\) to refine the features of the generator. In the following Sec. 4.1 and Sec. 4.2, we will describe how we ensure the latent code \\(w^{+}\\) and refined feature belong to the canonical space, respectively. Furthermore, we introduce an occlusion-aware mix tri-plane in Sec. 4.3 to avoid the distortion of invisible regions reconstruction. In Sec. 4.4, we exhibit how to perform 3D semantic editing with our inversion method." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.642, + 0.314, + 0.657 + ], + "angle": 0, + "content": "4.1. Geometry-aware Encoder" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.663, + 0.47, + 0.83 + ], + "angle": 0, + "content": "We design a geometry-aware encoder to obtain the latent code \\( w^{+} \\) given the input image \\( I \\) and corresponding rendering camera pose \\( c \\). We generate the inverted latent code \\( w^{+} \\) according to the backbone's pyramid feature progressively. It is worth noting that we choose Swin-transformer [25] as the backbone and further add attention modules at different scale feature layers for different level latent codes (more details of encoder architecture are in supplementary materials). After projecting the input image to the latent code \\( w^{+} \\), we can synthesize the tri-plane \\( w^{+} \\) through EG3D generator \\( G \\) and use rendering decoder \\( R_{dec} \\) to get the reconstruction image \\( I_{w^{+}} \\) under the rendering camera pose \\( c \\)." + }, + { + "type": "equation", + "bbox": [ + 0.206, + 0.84, + 0.469, + 0.86 + ], + "angle": 0, + "content": "\\[\nw ^ {+} = E (I), \\tag {1}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.205, + 0.857, + 0.343, + 0.87 + ], + "angle": 0, + "content": "\\[\nI _ {w ^ {+}} = R _ {d e c} (G (w ^ {+}), c)\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.417, + 0.893, + 0.515 + ], + "angle": 0, + "content": "To make the inverted \\( w^{+} \\) not deviate far from the canonical space \\( \\mathcal{W}_c \\) discussed in Sec. 3.1, we use a canonical latent discriminator [31] to discriminate between \\( w_{c} \\in \\mathcal{W}_{c} \\) and \\( w^{+} \\). The canonical latent discriminator, denoted as \\( \\mathcal{D}_{\\mathcal{W}_c} \\), is trained in an adversarial scheme with the non-saturating GAN loss [13] and \\( R_{1} \\) regularization [26], the loss of adversarial learning process can be written as below:" + }, + { + "type": "equation", + "bbox": [ + 0.511, + 0.526, + 0.891, + 0.604 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {L} _ {\\mathrm {a d v}} ^ {\\mathcal {D} \\mathcal {W} _ {c}} = - \\mathbb {E} [ \\log \\mathcal {D} _ {\\mathcal {W} _ {c}} (w _ {c}) ] - \\mathbb {E} [ \\log (1 - \\mathcal {D} _ {\\mathcal {W} _ {c}} (w _ {i})) ] (2) \\\\ + \\frac {\\gamma}{2} \\mathbb {E} \\left[ \\| \\nabla \\mathcal {D} _ {\\mathcal {W} _ {c}} \\left(w _ {c}\\right) \\| _ {2} \\right], \\\\ \\mathcal {L} _ {\\mathrm {a d v}} ^ {E} = - \\mathbb {E} \\left[ \\log \\mathcal {D} _ {\\mathcal {W} _ {c}} \\left(w _ {i}\\right) \\right], (3) \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.612, + 0.892, + 0.668 + ], + "angle": 0, + "content": "where \\(\\gamma\\) is the weight of \\(R_{1}\\) regularization, the \\(\\mathcal{L}_{\\mathrm{adv}}^{\\mathcal{D}_{\\mathcal{W}_c}}\\) and \\(\\mathcal{L}_{\\mathrm{adv}}^{E}\\) are the loss for the latent discriminator \\(\\mathcal{D}_{\\mathcal{W}_c}\\) and encoder respectively. \\(\\mathcal{D}_{\\mathcal{W}_c}\\) operates on \\(w_{c}\\) and each entry \\(w_{i}\\) of \\(w^{+}\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.67, + 0.892, + 0.835 + ], + "angle": 0, + "content": "As discussed in Sec. 3.1, the background depth of an integrated face should be limited in a range. To estimate the background depth, we first random sample 0.1 million front images with the canonical pose condition, then we obtain the depth maps and background regions of these images. We use the parsing method [52] to get a binary mask \\( M \\) where \\( M = 1 \\) indicates the background region and 0 otherwise. Finally, we calculate the average depth \\( D_{avg} \\) of background regions of these samples, and we set the \\( D_{avg} \\) as a regularization to constrain the background depth during inversion, the background regularization can be written as below:" + }, + { + "type": "equation", + "bbox": [ + 0.579, + 0.852, + 0.891, + 0.868 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {B G} = \\left\\| D \\odot M - D _ {\\text {a v g}} \\odot M \\right\\| _ {2}. \\tag {4}\n\\]" + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.887, + 0.502, + 0.898 + ], + "angle": 0, + "content": "2440" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.146, + 0.109, + 0.831, + 0.295 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.296, + 0.892, + 0.366 + ], + "angle": 0, + "content": "Figure 4: Overview of our method. Our framework could be divided into two parts. (1) \\(\\mathcal{W}\\) space inversion. We design an encoder \\(E\\) to invert input image \\(I\\) into \\(w^{+}\\) latent codes. The \\(w^{+}\\) latent codes are fed into a pre-trained EG3D generator \\(G\\) to get tri-plane\\(_{w^{+}}\\) and rendered into reconstruction image \\(I_{w^{+}}\\). (2) Complement the \\(\\mathcal{F}\\) space. We calculate the image residual \\(\\Delta I\\) between the input image and its reconstruction and propose AFA module to refine the F latent maps. The modified latent maps \\(F^{*}\\) are transformed into tri-plane\\(_{mix}\\) by occlusion-aware mix and rendered into the fine detailed inversion image \\(I_{F^{*}}\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.376, + 0.469, + 0.403 + ], + "angle": 0, + "content": "Here, \\(D\\) and \\(M\\) are the depth map and background mask inverted image under the front-view pose." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.404, + 0.469, + 0.473 + ], + "angle": 0, + "content": "In addition, we use reconstruction loss function \\(\\mathcal{L}_{rec}\\) follow pSp [35] in the training stage. The \\(\\mathcal{L}_{rec}\\) is composed by pixel-wise \\(\\mathcal{L}_2\\) loss, perceptual loss \\(\\mathcal{L}_{LPIPS}\\) [50], and facial identity similarity loss \\(\\mathcal{L}_{ID}\\) with pre-trained ArcFace network [9]:" + }, + { + "type": "equation", + "bbox": [ + 0.088, + 0.48, + 0.469, + 0.495 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {r e c} = \\left\\| I _ {w ^ {+}} - I \\right\\| _ {2} + \\mathcal {L} _ {L P I P S} \\left(I _ {w ^ {+}}, I\\right) + \\mathcal {L} _ {I D} \\left(I _ {w ^ {+}}, I\\right). \\tag {5}\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.5, + 0.334, + 0.515 + ], + "angle": 0, + "content": "4.2. Adaptive Feature Alignment" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.521, + 0.469, + 0.618 + ], + "angle": 0, + "content": "It is non-trivial to restore fine-detailed texture with only a highly compressed \\( w \\) latent code. Thus, adjusting high-dimension feature maps in the \\( \\mathcal{F} \\) space is natural to achieve high-fidelity inversion as mentioned in related 2D GAN inversion methods [3, 11, 45]. Moreover, it is worth noting that the feature maps \\( F \\) generated with our inverted \\( w^{+} \\) are in the canonical feature space \\( \\mathcal{F}_c \\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.618, + 0.469, + 0.756 + ], + "angle": 0, + "content": "We calculate the residual \\(\\Delta I\\) between \\(I\\) and \\(I_{w^{+}}\\) and hope to refine the feature maps to eliminate this residual. However, directly setting the residual as input and predicting the refined feature maps with a CNN to modify \\(F\\) is invalid. This is because the residual is highly entangled with the view of the input image, while \\(F\\) is in \\(\\mathcal{F}_c\\). When the view is not canonical, the refined feature maps with this residual can not project to the \\(\\mathcal{F}_c\\) space simply. Thus, aligning the residual feature maps to the \\(\\mathcal{F}_c\\) space is necessary to synthesize high-quality images, as mentioned in Sec. 3.2." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.757, + 0.469, + 0.867 + ], + "angle": 0, + "content": "According to the above analysis, we propose an adaptive feature alignment (AFA) module that enables automatic canonical space alignment by cross-attention mechanism, as shown in Fig 5. First, we use a CNN to capture the feature \\( F_{\\Delta I} \\) of \\( \\Delta I \\), and we take \\( F_{\\Delta I} \\) as the key \\( K \\), value \\( V \\), and the feature map \\( F \\) as a query \\( Q \\). Then, we utilize cross-attention modules to align the \\( F_{\\Delta I} \\) with \\( F \\) and output a feature \\( F_{\\text{align}} \\). Since the \\( F \\) is already in the canonical feature" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.376, + 0.89, + 0.459 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.461, + 0.892, + 0.518 + ], + "angle": 0, + "content": "Figure 5: The Architecture of AFA Module. We use a CNN to capture the feature \\( F_{\\Delta I} \\) of residual image \\( \\Delta I \\), and align the \\( F_{\\Delta I} \\) to \\( F \\) with cross attention module. Finally, we refine the \\( F \\) with the aligned feature \\( F_{\\text{align}} \\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.528, + 0.892, + 0.596 + ], + "angle": 0, + "content": "space \\(\\mathcal{F}_c\\), and the feature \\(F_{align}\\) can also have the properties of \\(\\mathcal{F}_c\\) space. Finally, we use the \\(F_{align}\\) to predict the scale map \\(\\gamma\\) and translation map \\(\\beta\\) to refine the \\(F\\) with Feature-wise Linear Modulation (FiLM) [34]. The whole process of our AFA module can be formulated as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.561, + 0.604, + 0.7, + 0.62 + ], + "angle": 0, + "content": "\\[\nF _ {\\Delta I} = C N N (\\Delta I),\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.561, + 0.622, + 0.812, + 0.637 + ], + "angle": 0, + "content": "\\[\nQ, K, V = W _ {Q} F, W _ {K} F _ {\\Delta I}, W _ {V} F _ {\\Delta I},\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.561, + 0.64, + 0.891, + 0.655 + ], + "angle": 0, + "content": "\\[\nF _ {\\text {a l i g n}} = \\text {A t t e n t i o n} (Q, K, V), \\tag {6}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.561, + 0.656, + 0.83, + 0.672 + ], + "angle": 0, + "content": "\\[\n\\gamma , \\beta = C o n v _ {\\gamma} (F _ {a l i g n}), C o n v _ {\\beta} (F _ {a l i g n}),\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.562, + 0.674, + 0.686, + 0.689 + ], + "angle": 0, + "content": "\\[\nF ^ {*} = \\gamma \\odot F + \\beta ,\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.699, + 0.892, + 0.781 + ], + "angle": 0, + "content": "where \\( W_{Q}, W_{K}, W_{V} \\) are learnable projection heads and \\( d \\) is the dimension of feature, the \\( F^{*} \\) is the final output of our AFA module. With this adaptive alignment, we achieve a detailed complement of \\( \\mathcal{F}_c \\) space. Note that we adopt \\( \\mathcal{L}_{total} \\) and a \\( \\mathcal{L}_2 \\) regularization loss on \\( \\Delta F = F^{*} - F \\) when training the AFA module." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.79, + 0.776, + 0.805 + ], + "angle": 0, + "content": "4.3. Occlusion-aware Mix Tri-plane" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.892, + 0.867 + ], + "angle": 0, + "content": "The image residual \\(\\Delta I\\) only contains information in the visible area of the input view. Using single-view residuals to modify the entire \\(F\\) will lead to distortion at the occlusion region. To solve this problem, we propose the Occlusion-" + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.887, + 0.501, + 0.898 + ], + "angle": 0, + "content": "2441" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.127, + 0.22, + 0.139 + ], + "angle": 0, + "content": "aware Mix Tri-plane." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.14, + 0.469, + 0.23 + ], + "angle": 0, + "content": "The tri-plane contains all points in the 3D space which are divided into visible points set and occlusion points set according to the input view. Here, we define the 3D points viewed in the input image in tri-plane as the visible points set \\(\\mathcal{V}_{(x,y,z)}\\), points in the occlusion regions as occlusion points set \\(\\mathcal{O}_{(x,y,z)}\\). We can get the depth map \\(D\\) under the input view, and the two points set can be defined by:" + }, + { + "type": "equation", + "bbox": [ + 0.088, + 0.239, + 0.469, + 0.282 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {V} _ {(x, y, z)} = \\left\\{\\left[ x, y, z \\right] ^ {T}: \\left[ x, y, z \\right] ^ {T} = \\pi D (u, v) \\mathcal {K} ^ {- 1} \\left[ u, v, 1 \\right] ^ {T} \\right\\}, \\\\ \\mathcal {O} _ {(x, y, z)} = \\mathbb {R} ^ {3} \\backslash \\mathcal {V} _ {(x, y, z)}, \\tag {7} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.284, + 0.47, + 0.338 + ], + "angle": 0, + "content": "where \\([u,v,1]\\) is the pixel homogeneous coordinate of the input image, \\(\\pi\\) is the extrinsic camera parameter matrix of the input view, \\(D(u,v)\\) is the depth of pixel \\([u,v]\\), \\(\\mathcal{K}\\) is the intrinsic camera parameter matrix." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.34, + 0.469, + 0.38 + ], + "angle": 0, + "content": "After determining the visible area, we can supplement the refined details of the input view to the tri-plane. We define the occlusion-aware mix tri-plane as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.143, + 0.391, + 0.469, + 0.46 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\operatorname {t r i - p l a n e} _ {w ^ {+}} = G \\left(w ^ {+}\\right), \\\\ \\operatorname {t r i - p l a n e} _ {F ^ {*}} = G \\left(F ^ {*}\\right), (8) \\\\ \\left. \\operatorname {t r i - p l a n e} _ {\\text {m i x}} = \\operatorname {t r i - p l a n e} _ {F ^ {*}} \\right| _ {(x, y, z) \\in \\mathcal {V}} (6) \\\\ + \\operatorname {t r i - p l a n e} _ {w +} | _ {(x, y, z) \\in \\mathcal {O}}, \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.471, + 0.469, + 0.526 + ], + "angle": 0, + "content": "where \\( w^{+} \\) is the latent code learned from the encoder, and \\( F^{*} \\) is the refined feature map. Finally, we use tri-planes mix with rendering decoder to synthesize images under different views when inference." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.537, + 0.172, + 0.551 + ], + "angle": 0, + "content": "4.4. Editing" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.558, + 0.469, + 0.669 + ], + "angle": 0, + "content": "To achieve 3D-consistent editing, we need to modify both \\( w^{+} \\) and \\( F^{*} \\). We first get the edited latent code \\( \\hat{w}^{+} \\) through classic latent code editing methods [33, 37]. Then for \\( F^{*} \\), we follow FS [48] to extract the features \\( F^{\\hat{w}^{+}} \\) and \\( F^{w} \\) from the generator convolution layer with input \\( \\hat{w}^{+} \\) and \\( w \\), respectively. Finally, we calculate the difference between these two features and add it to the \\( F^{*} \\) to get the edited features \\( \\hat{F^{*}} \\):" + }, + { + "type": "equation", + "bbox": [ + 0.19, + 0.681, + 0.469, + 0.696 + ], + "angle": 0, + "content": "\\[\n\\hat {F} ^ {*} = F ^ {*} + F ^ {\\hat {w} ^ {+}} - F ^ {w}. \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.711, + 0.469, + 0.754 + ], + "angle": 0, + "content": "With the modified \\(\\hat{w}^{+}\\) and \\(\\hat{F}^{*}\\), we use the method in section 4.3 to get edited mix tri-plane, and use rendering decoder to synthesize 3D-consistent edited images." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.763, + 0.168, + 0.777 + ], + "angle": 0, + "content": "4.5. Losses." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.785, + 0.469, + 0.827 + ], + "angle": 0, + "content": "In the first training stage, we use the loss function mentioned in Sec 4.1. For the input view reconstruction, the loss \\(\\mathcal{L}_{rec}\\) is computed by:" + }, + { + "type": "equation", + "bbox": [ + 0.078, + 0.839, + 0.468, + 0.867 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {r e c} = \\lambda_ {1} \\| I _ {w ^ {+}} - I \\| _ {2} + \\lambda_ {2} \\mathcal {L} _ {L P I P S} \\left(I _ {w ^ {+}}, I\\right) + \\lambda_ {3} \\mathcal {L} _ {I D} \\left(I _ {w ^ {+}}, I\\right), \\tag {10}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.127, + 0.892, + 0.167 + ], + "angle": 0, + "content": "where \\(\\lambda_{1} = 1.0, \\lambda_{2} = 0.8, \\lambda_{3} = 0.25\\). The total loss for training our encoder and the canonical latent discriminator can be written as:" + }, + { + "type": "equation", + "bbox": [ + 0.534, + 0.173, + 0.891, + 0.19 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {t o t a l}} ^ {E} = \\mathcal {L} _ {\\mathrm {a d v}} ^ {\\mathcal {D} w _ {c}} + \\lambda_ {4} \\mathcal {L} _ {\\mathrm {a d v}} ^ {E} + \\lambda_ {5} \\mathcal {L} _ {B G} + \\mathcal {L} _ {\\text {r e c}}, \\tag {11}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.195, + 0.892, + 0.251 + ], + "angle": 0, + "content": "where \\(R_{1}\\) regularization weight \\(\\gamma = 10\\), \\(\\lambda_4 = 0.05\\), \\(\\lambda_5 = 5.0\\). Moreover, we apply regularization on \\(\\Delta w^{+} = (w_{1} - w_{0}, w_{2} - w_{0}, \\dots, w_{13} - w_{0})\\) by \\(\\mathcal{L}_2\\) norm, i.e. \\(\\mathcal{L}_{w^+} = \\lambda_6\\| \\Delta w^+\\|_2\\), where \\(\\lambda_6 = 0.001\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.251, + 0.892, + 0.335 + ], + "angle": 0, + "content": "Once the loss in the first stage is converged, we freeze the encoder parameters and drop the canonical latent discriminator and losses \\(\\mathcal{L}_{\\mathrm{adv}}^{\\mathcal{D}_{\\mathcal{W}_c}},\\mathcal{L}_{\\mathrm{adv}}^E,\\mathcal{L}_{w^+}\\), but add a \\(\\mathcal{L}_2\\) regularization on \\(\\Delta F = F^{*} - F\\) with \\(\\lambda_7 = 0.0001\\) for training the AFA module, i.e. \\(\\mathcal{L}_{\\Delta F} = \\lambda_7\\| \\Delta F\\| _2\\). We apply the loss settings to both human data and cat data." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.335, + 0.892, + 0.376 + ], + "angle": 0, + "content": "For re-implemented pSp [35] and e4e [42], we train it with the same loss weight in our settings, and train them until the losses converge." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.387, + 0.632, + 0.403 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.41, + 0.892, + 0.519 + ], + "angle": 0, + "content": "Experiment setup. We evaluate our method on human faces and cat faces. For human faces, we use FFHQ [1] dataset for training, and CelebA-HQ [18] and MEAD [44] for evaluation. For the cat faces, we use AFHQ-CAT [7] for training and evaluation. In addition, we employ the pretrained EG3D generator and obtain the corresponding camera parameters of each image following the official implementation in EG3D." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.52, + 0.892, + 0.604 + ], + "angle": 0, + "content": "Baselines. We compare our method with encoder (IDE-3D [40]) and optimization-based (PTI [36] and Pose Opt. [21]) baselines in these two aspects. Moreover, we build two encoder baselines imitating the state-of-the-art StyleGAN inverters, pSp [35] and e4e [42], and present the model structure in the supplementary." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.61, + 0.688, + 0.625 + ], + "angle": 0, + "content": "5.1. Qualitative analysis" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.631, + 0.892, + 0.699 + ], + "angle": 0, + "content": "Source View Inversion Results. Fig. 6 shows the inversion performance comparison between ours and other methods. Our method's hair details and facial similarity are obviously competitive with optimization methods and surpass all the encoder-based methods." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.7, + 0.892, + 0.811 + ], + "angle": 0, + "content": "Novel View Synthesis Results. The comparison results are shown in Fig. 6. Inspecting the eye gaze direction and person's identity preservation when changing to novel views can reveal the differences. It can be seen that on some extreme side-face camera poses, some optimization methods produce artifacts and geometry distortions. Our method can keep synthesizing 3D-consistent images faithful to the person's identity in the input." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.818, + 0.698, + 0.832 + ], + "angle": 0, + "content": "5.2.Quantitative analysis" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.839, + 0.892, + 0.867 + ], + "angle": 0, + "content": "We calculate the mean square error (MSE), LPIPS [50], and FID [16] between the source image and its inversion." + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.887, + 0.502, + 0.898 + ], + "angle": 0, + "content": "2442" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.121, + 0.123, + 0.85, + 0.434 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.438, + 0.896, + 0.482 + ], + "angle": 0, + "content": "Figure 6: Visual comparison of inversion and novel-view synthesized results between our method and others. Our method surpasses all the encoder-based methods and is competitive with optimization methods in recovering texture details, i.e., our method prevents the eye orientation from changing with the camera view and artifacts in the novel view." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.493, + 0.893, + 0.615 + ], + "angle": 0, + "content": "
CategoryMethodReconstruction QualityNovel View Quality
Input Viewyaw=±60°yaw=0°
MSE ↓LPIPS ↓FID ↓ID ↑Geo. Err. ↓Time (s) ↓LPIPS ↓FID ↓ID ↑Geo. Err. ↓LPIPS ↓FID ↓ID ↑Geo. Err. ↓
OptimizationPTI [36]0.01630.091818.00.84170.0850115.20.292669.80.6210.14810.192553.50.7180.1006
Pose Opt. [21]0.01640.087917.50.83900.0759219.70.44771320.3210.17630.243660.20.6050.1504
Encoder-basedIDE-3D [40]0.10560.280643.60.71940.18350.06590.331779.00.5050.29140.307463.70.5130.2528
pSp-3D [35]0.07260.208231.20.78170.18460.12840.322365.70.5910.12870.313265.20.6710.1789
e4e-3D [42]0.08080.228133.00.73590.11610.13030.249557.70.5880.12690.239453.80.6530.1305
Ours-w+0.06970.198130.90.78730.11000.09630.230352.20.6550.09430.237254.10.6850.0955
Ours0.03010.125720.50.87520.09870.22620.219250.90.7000.09500.220451.70.7430.0944
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.624, + 0.895, + 0.669 + ], + "angle": 0, + "content": "Table 1: Comparison with state-of-the-art methods on inversion performance. The numbers in bold are the best performance of the optimization and encoder-based methods, respectively. Metrics of Reconstruction Quality are calculated under the input view. Metrics of Novel View Quality are the average of multi-view. The yaw angle is the source view angle." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.689, + 0.471, + 0.803 + ], + "angle": 0, + "content": "We adopt a pre-trained face key point detector parsenet [52] to calculate the identity similarity. To measure the geometry properties, we followed [5, 38], utilizing a pre-trained 3D face reconstruction model to extract a \"pseudo\" ground truth depth map from the source image. Then, we obtain the depth of inversion and normalize all depth maps to zero means and unit variance to calculate geometry error (Geo. Err.) by using average \\(\\mathcal{L}_2\\) distance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.473, + 0.868 + ], + "angle": 0, + "content": "Source View Inversion Results. Table 1 presents the quantitative comparison of the input view image reconstruction on CelebA-HQ test dataset. Our method is two orders of magnitude faster than the optimized methods with similar" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.69, + 0.892, + 0.718 + ], + "angle": 0, + "content": "performance, which is notably better than other encoder-based methods." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.728, + 0.893, + 0.868 + ], + "angle": 0, + "content": "Novel View Synthesis Results. In order to measure the multi-view consistency and the synthesized quality, we evaluate our method and baselines with a multi-view dataset, MEAD [44]. Each person in MEAD has five images with increasing yaw angles. We select one angle as the input view, invert the input image and synthesize the other four novel views. Then we use the same metrics to calculate the difference between the synthesized images and the ground truth. The quantitative comparison between the novel view synthesized results and the ground truth in dif" + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.887, + 0.502, + 0.898 + ], + "angle": 0, + "content": "2443" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.126, + 0.468, + 0.306 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.317, + 0.471, + 0.428 + ], + "angle": 0, + "content": "Figure 7: Ablation of Geometry-aware Encoder. All images are synthesized only with \\( w^{+} \\). Without both modules, \\( w^{+} \\) fails to generate integrated 3D geometry and texture. The \\( L_{BG} \\) helps distinguish foreground and background. With \\( \\mathcal{D}_{\\mathcal{W}_c} \\), we can get good inversion under the input view but fail under the novel view. With both modules, \\( w^{+} \\) can obtain an integrated side face of the woman, which is occlusion under the input view." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.444, + 0.47, + 0.554 + ], + "angle": 0, + "content": "ferent views is shown in Table 1. Our method shows similar performance with PTI when the input image is a front face \\((\\mathrm{yaw} = 0^{\\circ})\\). When inverting side faces, the difficulty of inversion increases drastically when the yaw angle increases. We calculated the metrics of the largest yaw angle in MEAD \\((\\mathrm{yaw} = \\pm 60^{\\circ})\\), and our model has robust performance when the test yaw angle varies. However, the performance of optimization methods degrades remarkably at an extreme angle." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.566, + 0.251, + 0.58 + ], + "angle": 0, + "content": "5.3. Ablation Analysis" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.588, + 0.47, + 0.629 + ], + "angle": 0, + "content": "We present ablation studies with qualitative analysis of our proposed method below, and the corresponding numerical ablation results are in our supplementary." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.63, + 0.469, + 0.755 + ], + "angle": 0, + "content": "Geometry-aware Encoder. We conduct ablation experiments and make qualitative comparisons to verify that our proposed canonical latent discriminator \\((\\mathcal{D}_{\\mathcal{W}_c})\\) and background regularization \\((\\mathcal{L}_{BG})\\) contribute to restoring 3D geometry. Generally, recovering the geometry from a side face input is more challenging and we test such a case. As shown in Fig. 7, only if we adopt the canonical discriminator and the background regularization could we obtain a satisfactory foreground and background geometry." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.755, + 0.469, + 0.81 + ], + "angle": 0, + "content": "Adaptive Feature Alignment. We proposed Adaptive Feature Alignment (AFA) to refine the \\(F\\) latent map and add texture details from the source view. Fig. 8 demonstrates that we can recover more details with AFA." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.47, + 0.867 + ], + "angle": 0, + "content": "Occlusion-aware Mix Tri-plane. To verify the necessity of our proposed occlusion-aware mix tri-plane, we ablate this operation and visualize the novel view results in Fig. 9. The occlusion map shows the spatial position of surface points" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.125, + 0.696, + 0.179 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.698, + 0.125, + 0.89, + 0.178 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.184, + 0.892, + 0.238 + ], + "angle": 0, + "content": "Figure 8: Ablation of Adaptive Feature Alignment. We replace AFA with a CNN network and obtain the results. Without feature alignment, it is difficult to reconstruct the hair and facial details." + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.242, + 0.892, + 0.389 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.395, + 0.892, + 0.464 + ], + "angle": 0, + "content": "Figure 9: Ablation of Occlusion-aware mix tri-plane. We visualize the occlusion regions \\(\\mathcal{O}_{(x,y,z)}\\) of the input view in the last column (black points). The green arrow points out \\(\\mathcal{O}_{(x,y,z)}\\) in the novel view, and it is obvious that the occlusion-aware mix tri-plane can avoid artifacts." + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.469, + 0.891, + 0.677 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.683, + 0.892, + 0.725 + ], + "angle": 0, + "content": "Figure 10: Editing result under novel views. We add three different attributes to three faces. Our method generates both realistic editing and 3D-consistent novel views." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.74, + 0.892, + 0.795 + ], + "angle": 0, + "content": "in ray sampling, the visible region in the original view is white, and the occlusion region is black. Without the mix tri-plane, the occlusion area from the source view is easy to produce artifacts in novel views." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.804, + 0.707, + 0.818 + ], + "angle": 0, + "content": "5.4. Image Editing Results" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.825, + 0.892, + 0.867 + ], + "angle": 0, + "content": "In GAN inversion-based image manipulation, the editability and the reconstruction trade-off widely exists in both 2D and 3D scenarios. We validate the editing method" + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.887, + 0.502, + 0.898 + ], + "angle": 0, + "content": "2444" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.078, + 0.123, + 0.895, + 0.262 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.3, + 0.265, + 0.668, + 0.279 + ], + "angle": 0, + "content": "Figure 11: Results of our encoder in other 3D GANs." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.285, + 0.468, + 0.312 + ], + "angle": 0, + "content": "
MSE ↓LPIPS ↓FID ↓MSE ↓LPIPS ↓FID ↓
w/o AFA0.05860.231713.43w/ AFA0.03670.174510.82
" + }, + { + "type": "table_caption", + "bbox": [ + 0.116, + 0.315, + 0.431, + 0.33 + ], + "angle": 0, + "content": "Table 2: Ablation of AFA on ShapeNet Cars." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.343, + 0.47, + 0.468 + ], + "angle": 0, + "content": "mentioned in Sec. 4.4 and display the multi-view edited results in Fig. 10. We choose three different edit directions, 'Young' to reduce person's age, 'Unhappy' to change emotion, and 'Glasses' to add accessories. It is noticeable that our method not only restores the geometric and texture information of the input image but also ensures the editing consistency of multi-view. The edited results demonstrate that our inversion method can be well applied to the facial image editing tasks." + }, + { + "type": "image", + "bbox": [ + 0.143, + 0.479, + 0.413, + 0.678 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.688, + 0.47, + 0.73 + ], + "angle": 0, + "content": "Figure 12: (a) Tri-plane canonical feature space. (b) Results of our method on ShapeNet Cars datasets. Best viewed zoomed in and in color." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.74, + 0.227, + 0.755 + ], + "angle": 0, + "content": "6. Generalization" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.763, + 0.47, + 0.82 + ], + "angle": 0, + "content": "Our method can be adapted to other 3D GANs (e.g., EpiGRAF [39] and StyleSDF [32]) and it works also with categories where pose estimation and canonicalization are more difficult (e.g., Shapenet cars)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.471, + 0.867 + ], + "angle": 0, + "content": "Extension to other 3D GANs. We choose EG3D as our base 3D GAN due to its superior performance, but our method can also be applied to other 3D GANs. The canon-" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.287, + 0.892, + 0.481 + ], + "angle": 0, + "content": "ical space, which plays a vital role in 3D GAN inversion, is commonly presented in the latent space (i.e., \\( w^{+} \\)space) of 3D GANs. By inverting images into the canonical space, we preserve geometry and achieve high-fidelity reconstruction, as demonstrated in our experiments on EpiGRAF [39] and StyleSDF [32] in Fig. 11. The results of w/o \\( \\mathcal{D}_{\\mathcal{W}_c}, L_{BG} \\) mean that we only use the base encoder without the canonical latent discriminator and the background depth regularization. In contrast, w/ \\( \\mathcal{D}_{\\mathcal{W}_c}, L_{BG} \\) is our full encoder model. The noticeable performance gap proves the powerful inversion ability of our method. Our method explores the canonical space's characteristics, ensuring distortion-free shape generation and exceptional performance in image 3D inversion." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.488, + 0.893, + 0.584 + ], + "angle": 0, + "content": "Extension to ShapeNet Cars. Fig. 12 shows (a) the canonical space and (b) the inversion results on ShapeNet Cars. Even without identity loss, our method can achieve good performance(see the Col.3,5 of (b)). As the tri-plane is canonical, without the AFA module, the residual feature can not align with the canonical feature space (see the Col. 2,4 of (b) and Table 2)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.586, + 0.619, + 0.6 + ], + "angle": 0, + "content": "7. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.603, + 0.892, + 0.782 + ], + "angle": 0, + "content": "In this work, we explore the inherent property of EG3D's latent space and find that the key to achieve high-quality shape and texture inversion is inverting input images to the canonical space. In light of this, we design an efficient geometry-aware encoder with an adaptive feature alignment module and demonstrate their effectiveness. Besides, we propose an occlusion-aware mix tri-plane to avoid invisible region distortion in novel views. Extensive experiments demonstrate that our method has competitive inversion performance with optimization-based methods, but operates two orders of magnitude faster. In addition, our method is demonstrated to be a powerful tool for realistic and 3D view-consistent editing of facial images." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.785, + 0.681, + 0.799 + ], + "angle": 0, + "content": "8. Acknowledgement" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.798, + 0.892, + 0.867 + ], + "angle": 0, + "content": "This work was supported by the National Key R&D Program of China (2022YFB4701400/4701402), SZSTC Grant (JCYJ20190809172201639, WDZC20200820200655001), Shenzhen Key Laboratory (ZDSYS20210623092001004), and Beijing Key Lab of Networked Multimedia." + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.887, + 0.502, + 0.898 + ], + "angle": 0, + "content": "2445" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.125, + 0.173, + 0.139 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.148, + 0.47, + 0.199 + ], + "angle": 0, + "content": "[1] Rameen Abdul, Yipeng Qin, and Peter Wonka. Image2stylegan: How to embed images into the stylegan latent space? In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4432-4441, 2019. 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.2, + 0.472, + 0.25 + ], + "angle": 0, + "content": "[2] Yuval Alaluf, Or Patashnik, and Daniel Cohen-Or. Restyle: A residual-based stylegan encoder via iterative refinement. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6711–6720, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.251, + 0.471, + 0.315 + ], + "angle": 0, + "content": "[3] Yuval Alaluf, Omer Tov, Ron Mokady, Rinon Gal, and Amit Bermano. Hyperstyle: Stylegan inversion with hypernetworks for real image editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18511-18521, 2022. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.315, + 0.47, + 0.366 + ], + "angle": 0, + "content": "[4] Lucy Chai, Jun-Yan Zhu, Eli Shechtman, Phillip Isola, and Richard Zhang. Ensembling with deep generative views. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14997-15007, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.367, + 0.47, + 0.442 + ], + "angle": 0, + "content": "[5] Eric R Chan, Connor Z Lin, Matthew A Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas J Guibas, Jonathan Tremblay, Sameh Khamis, et al. Efficient geometry-aware 3d generative adversarial networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 16123-16133, 2022. 1, 2, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.444, + 0.469, + 0.507 + ], + "angle": 0, + "content": "[6] Eric R Chan, Marco Monteiro, Petr Kellnhofer, Jiajun Wu, and Gordon Wetzstein. pi-gan: Periodic implicit generative adversarial networks for 3d-aware image synthesis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5799-5809, 2021. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.508, + 0.469, + 0.558 + ], + "angle": 0, + "content": "[7] Yunjoy Choi, Youngjung Uh, Jaejun Yoo, and Jung-Woo Ha. Stargan v2: Diverse image synthesis for multiple domains. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8188-8197, 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.559, + 0.469, + 0.609 + ], + "angle": 0, + "content": "[8] Edo Collins, Raja Bala, Bob Price, and Sabine Susstrunk. Editing in style: Uncovering the local semantics of gans. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5771-5780, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.61, + 0.469, + 0.673 + ], + "angle": 0, + "content": "[9] Jiankang Deng, Jia Guo, Niannan Xue, and Stefanos Zafeiriou. Arcface: Additive angular margin loss for deep face recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4690-4699, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.674, + 0.469, + 0.736 + ], + "angle": 0, + "content": "[10] Yu Deng, Jiaolong Yang, Jianfeng Xiang, and Xin Tong. Gram: Generative radiance manifolds for 3d-aware image generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10673-10683, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.738, + 0.469, + 0.8 + ], + "angle": 0, + "content": "[11] Tan M Dinh, Anh Tuan Tran, Rang Nguyen, and Binh-Son Hua. Hyperinverter: Improving stylegan inversion via hypernetwork. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11389-11398, 2022. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.802, + 0.469, + 0.841 + ], + "angle": 0, + "content": "[12] Shubham Goel, Angjoo Kanazawa, and Jitendra Malik. Shape and viewpoint without keypoints. In European Conference on Computer Vision, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.841, + 0.469, + 0.867 + ], + "angle": 0, + "content": "[13] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.148, + 0.472, + 0.867 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.127, + 0.892, + 0.153 + ], + "angle": 0, + "content": "Yoshua Bengio. Generative adversarial nets. In Advances in Neural Information Processing Systems, 2014. 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.154, + 0.892, + 0.204 + ], + "angle": 0, + "content": "[14] Jiatao Gu, Lingjie Liu, Peng Wang, and Christian Theobalt. Stylenerf: A style-based 3d-aware generator for high-resolution image synthesis. arXiv preprint arXiv:2110.08985, 2021. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.206, + 0.892, + 0.256 + ], + "angle": 0, + "content": "[15] Paul Henderson, Vagia Tsiminaki, and Christoph H Lampert. Leveraging 2d data to learn textured 3d mesh generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.258, + 0.892, + 0.32 + ], + "angle": 0, + "content": "[16] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in Neural Information Processing Systems, 30, 2017. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.322, + 0.892, + 0.373 + ], + "angle": 0, + "content": "[17] Angjoo Kanazawa, Shubham Tulsiani, Alexei A. Efros, and Jitendra Malik. Learning category-specific mesh reconstruction from image collections. In European Conference on Computer Vision, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.374, + 0.892, + 0.424 + ], + "angle": 0, + "content": "[18] Tero Karras, Timo Aila, Samuli Laine, and Jaakko Lehtinen. Progressive growing of GANs for improved quality, stability, and variation. In International Conference On Learning Representations, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.426, + 0.892, + 0.476 + ], + "angle": 0, + "content": "[19] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.478, + 0.892, + 0.54 + ], + "angle": 0, + "content": "[20] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of StyleGAN. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.542, + 0.892, + 0.58 + ], + "angle": 0, + "content": "[21] Jaehoon Ko, Kyusun Cho, Daewon Choi, Kwangrok Ryoo, and Seungryong Kim. 3d gan inversion with pose optimization. arXiv preprint arXiv:2210.07301, 2022. 1, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.581, + 0.892, + 0.631 + ], + "angle": 0, + "content": "[22] Yushi Lan, Xuyi Meng, Shuai Yang, Chen Change Loy, and Bo Dai. Self-supervised geometry-aware encoder for style-based 3d gan inversion. arXiv preprint arXiv:2212.07409, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.633, + 0.892, + 0.684 + ], + "angle": 0, + "content": "[23] Yu-Jhe Li, Tao Xu, Bichen Wu, Ningyuan Zheng, Xiaoliang Dai, Albert Pumarola, Peizhao Zhang, Peter Vajda, and Kris Kitani. 3d-aware encoding for style-based neural radiance fields. arXiv preprint arXiv:2211.06583, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.685, + 0.892, + 0.723 + ], + "angle": 0, + "content": "[24] Hongyu Liu, Yibing Song, and Qifeng Chen. Delving stylegan inversion for image editing: A foundation latent space viewpoint. arXiv preprint arXiv:2211.11448, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.724, + 0.892, + 0.788 + ], + "angle": 0, + "content": "[25] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10012-10022, 2021. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.789, + 0.892, + 0.839 + ], + "angle": 0, + "content": "[26] Lars Mescheder, Andreas Geiger, and Sebastian Nowozin. Which training methods for gans do actually converge? In International Conference on Machine Learning, pages 3481-3490. PMLR, 2018. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.84, + 0.892, + 0.867 + ], + "angle": 0, + "content": "[27] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf:" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.127, + 0.892, + 0.867 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.888, + 0.502, + 0.898 + ], + "angle": 0, + "content": "2446" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.127, + 0.469, + 0.164 + ], + "angle": 0, + "content": "Representing scenes as neural radiance fields for view synthesis. In European Conference on Computer Vision, 2020. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.166, + 0.469, + 0.228 + ], + "angle": 0, + "content": "[28] Thu Nguyen-Phuoc, Chuan Li, Lucas Theis, Christian Richardt, and Yong-Liang Yang. Hologan: Unsupervised learning of 3d representations from natural images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7588-7597, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.23, + 0.469, + 0.292 + ], + "angle": 0, + "content": "[29] Thu H Nguyen-Phuoc, Christian Richardt, Long Mai, Yongliang Yang, and Niloy Mitra. Blockgan: Learning 3d object-aware scene representations from unlabelled images. Advances in Neural Information Processing Systems, 33:6767-6778, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.294, + 0.469, + 0.355 + ], + "angle": 0, + "content": "[30] Michael Niemeyer and Andreas Geiger. Giraffe: Representing scenes as compositional generative neural feature fields. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11453-11464, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.357, + 0.469, + 0.395 + ], + "angle": 0, + "content": "[31] Yotam Nitzan, Amit Bermano, Yangyan Li, and Daniel Cohen-Or. Face identity disentanglement via latent space mapping. arXiv preprint arXiv:2005.07728, 2020. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.396, + 0.469, + 0.47 + ], + "angle": 0, + "content": "[32] Roy Or-El, Xuan Luo, Mengyi Shan, Eli Shechtman, Jeong Joon Park, and Ira Kemelmacher-Shlizerman. Stylesdf: High-resolution 3d-consistent image and geometry generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13503–13513, 2022. 1, 2, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.472, + 0.469, + 0.534 + ], + "angle": 0, + "content": "[33] Or Patashnik, Zongze Wu, Eli Shechtman, Daniel Cohen-Or, and Dani Lischinski. Styleclip: Text-driven manipulation of stylegan imagery. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2085–2094, 2021. 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.536, + 0.469, + 0.585 + ], + "angle": 0, + "content": "[34] Ethan Perez, Florian Strub, Harm De Vries, Vincent Dumoulin, and Aaron Courville. Film: Visual reasoning with a general conditioning layer. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 32, 2018. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.587, + 0.469, + 0.661 + ], + "angle": 0, + "content": "[35] Elad Richardson, Yuval Alaluf, Or Patashnik, Yotam Nitzan, Yaniv Azar, Stav Shapiro, and Daniel Cohen-Or. Encoding in style: a stylegan encoder for image-to-image translation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2287–2296, 2021. 3, 4, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.663, + 0.469, + 0.712 + ], + "angle": 0, + "content": "[36] Daniel Roich, Ron Mokady, Amit H Bermano, and Daniel Cohen-Or. Pivotal tuning for latent-based editing of real images. ACM Transactions on Graphics (TOG), 42(1):1-13, 2022. 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.714, + 0.469, + 0.775 + ], + "angle": 0, + "content": "[37] Yujun Shen, Jinjin Gu, Xiaou Tang, and Bolei Zhou. Interpreting the latent space of gans for semantic face editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9243-9252, 2020. 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.778, + 0.469, + 0.828 + ], + "angle": 0, + "content": "[38] Yichun Shi, Divyansh Aggarwal, and Anil K Jain. Lifting 2d stylegan for 3d-aware face generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6258-6266, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.829, + 0.469, + 0.866 + ], + "angle": 0, + "content": "[39] Ivan Skorokhodov, Sergey Tulyakov, Yiqun Wang, and Peter Wonka. Epigraph: Rethinking training of 3d gans. arXiv preprint arXiv:2206.10535, 2022. 9" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.127, + 0.469, + 0.866 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.128, + 0.892, + 0.178 + ], + "angle": 0, + "content": "[40] Jingxiang Sun, Xuan Wang, Yichun Shi, Lizhen Wang, Jue Wang, and Yebin Liu. Ide-3d: Interactive disentangled editing for high-resolution 3d-aware portrait synthesis. arXiv preprint arXiv:2205.15517, 2022. 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.18, + 0.892, + 0.228 + ], + "angle": 0, + "content": "[41] Maxim Tatarchenko, Alexey Dosovitskiy, and Thomas Brox. Multi-view 3D models from single images with a convolutional network. In European Conference on Computer Vision, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.231, + 0.892, + 0.28 + ], + "angle": 0, + "content": "[42] Omer Tov, Yuval Alaluf, Yotam Nitzan, Or Patashnik, and Daniel Cohen-Or. Designing an encoder for stylegan image manipulation. ACM Transactions on Graphics (TOG), 40(4):1-14, 2021. 2, 3, 4, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.283, + 0.892, + 0.344 + ], + "angle": 0, + "content": "[43] Shubham Tulsiani, Hao Su, Leonidas J. Guibas, Alexei A. Efros, and Jitendra Malik. Learning shape abstractions by assembling volumetric primitives. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.347, + 0.892, + 0.41 + ], + "angle": 0, + "content": "[44] Kaisiyuan Wang, Qianyi Wu, Linsen Song, Zhuoqian Yang, Wayne Wu, Chen Qian, Ran He, Yu Qiao, and Chen Change Loy. Mead: A large-scale audio-visual dataset for emotional talking-face generation. In European Conference on Computer Vision, pages 700–717. Springer, 2020. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.412, + 0.892, + 0.473 + ], + "angle": 0, + "content": "[45] Tengfei Wang, Yong Zhang, Yanbo Fan, Jue Wang, and Qifeng Chen. High-fidelity gan inversion for image attribute editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11379-11388, 2022. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.476, + 0.892, + 0.538 + ], + "angle": 0, + "content": "[46] Zongze Wu, Dani Lischinski, and Eli Shechtman. Stylespace analysis: Disentangled controls for stylegan image generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12863-12872, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.541, + 0.892, + 0.589 + ], + "angle": 0, + "content": "[47] Jiaxin Xie, Hao Ouyang, Jingtan Piao, Chenyang Lei, and Qifeng Chen. High-fidelity 3d gan inversion by pseudomulti-view optimization. arXiv preprint arXiv:2211.15662, 2022.1.3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.593, + 0.892, + 0.642 + ], + "angle": 0, + "content": "[48] Xu Yao, Alasdair Newson, Yann Gousseau, and Pierre Hellier. A style-based gan encoder for high fidelity reconstruction of images and videos. European Conference on Computer Vision, 2022. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.644, + 0.892, + 0.694 + ], + "angle": 0, + "content": "[49] Fei Yin, Yong Zhang, Xuan Wang, Tengfei Wang, Xiaoyu Li, Yuan Gong, Yanbo Fan, Xiaodong Cun, Ying Shan, Cengiz Oztireli, et al. 3d gan inversion with facial symmetry prior. arXiv preprint arXiv:2211.16927, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.696, + 0.892, + 0.759 + ], + "angle": 0, + "content": "[50] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 586-595, 2018. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.761, + 0.892, + 0.809 + ], + "angle": 0, + "content": "[51] Jiapeng Zhu, Yujun Shen, Deli Zhao, and Bolei Zhou. Indomain gan inversion for real image editing. In European Conference on Computer Vision, pages 592-608. Springer, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.812, + 0.888, + 0.848 + ], + "angle": 0, + "content": "[52] zllrunning. faceParsing.pytorch. https://github.com/zllrunning/faceParsing.PyTorch/, 2019.4.7" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.128, + 0.892, + 0.848 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.469, + 0.888, + 0.501, + 0.898 + ], + "angle": 0, + "content": "2447" + } + ] +] \ No newline at end of file diff --git a/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/d0a41b80-a701-4955-834c-d42058b2d111_origin.pdf b/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/d0a41b80-a701-4955-834c-d42058b2d111_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..175f7c4fc9fcb05321539e4a1fa2ca9c602afdd8 --- /dev/null +++ b/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/d0a41b80-a701-4955-834c-d42058b2d111_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:ad2606f8253e180fa04a0f4c5811a5b428deb4c177ddd625771452646f231f59 +size 3776304 diff --git a/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/full.md b/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/full.md new file mode 100644 index 0000000000000000000000000000000000000000..2fc64b0e5e6d9857ad6b35b14e11182dba6ea0ca --- /dev/null +++ b/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/full.md @@ -0,0 +1,360 @@ +# Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding + +Ziyang Yuan $^{1*}$ Yiming Zhu $^{1,2*}$ Yu Li $^{2\dagger}$ Hongyu Liu $^{3}$ Chun Yuan $^{1\dagger}$ + +$^{1}$ Tsinghua Shenzhen International Graduate School $^{2}$ International Digital Economy Academy (IDEA) $^{3}$ Hong Kong University of Science and Technology + +https://eg3d-goae.github.io + +![](images/ff4e090a71aaba990dfbc75a0a5c1a02ec427b18c727a3c606c60c5cc096ee83.jpg) +Figure 1: The inversion and editing results of our method on human portraits and cat images. The novel view synthesized images demonstrate that our method can achieve high-quality inversion and editing given a single image input. + +# Abstract + +3D GAN inversion aims to achieve high reconstruction fidelity and reasonable 3D geometry simultaneously from a single image input. However, existing 3D GAN inversion methods rely on time-consuming optimization for each individual case. In this work, we introduce a novel encoder-based inversion framework based on EG3D, one of the most widely-used 3D GAN models. We leverage the inherent properties of EG3D's latent space to design a discriminator and a background depth regularization. This enables us to train a geometry-aware encoder capable of converting the input image into corresponding latent code. Additionally, we explore the feature space of EG3D and develop an adaptive refinement stage that improves the representation ability of features in EG3D to enhance the recovery of fine-grained textural details. Finally, we propose an occlusion-aware fusion operation to prevent distortion in unobserved regions. Our method achieves impressive results comparable to optimization-based methods while operating up to 500 times faster. Our framework is well-suited for applications such as semantic editing. + +# 1. Introduction + +Recent advances in 3D-aware generative adversarial networks (GAN) (e.g. [5, 6, 14, 32]) have integrated neural radiance fields (NeRF) [27] into style-based generation, resulting in remarkable success in generating highly realistic 3D portraits. Similar to 2D GAN inversion techniques, 3D GAN inversion also projects images into the latent space of pre-trained 3D GAN models. However, in addition to pursuing faithful image reconstruction and preserving fined details, 3D GAN inversion also aims for accurate 3D geometry, which is critical for generating realistic and consistent multi-view images. This ability to ensure the correctness of 3D geometry is a crucial advantage of 3D GAN inversion over its 2D counterpart. + +Some optimization-based methods, such as [21, 47, 49], first invert the image to a latent code to obtain a coarse 3D shape. They then synthesize pseudo-multi-view images with this shape using a warping process. These pseudo images are used as supervision to optimize the parameters of the 3D GAN for more precise 3D geometry and better detail preservation. While these iterative optimization-based pipelines can prevent shape collapse and produce accurate + +results, the optimization process needs to be performed for each individual case, which is time-consuming and impractical for many applications. + +Several encoder-based methods [22, 23] leverage a pretrained 3D GAN to generate proxy data by randomly sampling latent codes and camera poses. They then employ these paired proxy data to train an encoder in a self-supervised fashion and further refine features in 3D GAN. These encoder-based techniques offer higher efficiency but lower high-fidelity reconstruction ability. Moreover, due to a domain gap between the paired proxy data and real images, the encoder may invert the in-the-wild images to unsuitable latent codes. To address this issue, we study the properties of the latent space in 3D GAN and develop a geometry-aware encoder that predicts the latent code incorporating these properties. Furthermore, since the latent code can not preserve details of input images well, we explore the characteristics of feature space in 3D GAN to help our method improve the performance in reconstructing the original appearance. The latent and feature spaces are widely discussed in 2D GAN inversion [11, 24, 42]. + +This paper presents a novel encoder-based method for inverting 3D images generated by EG3D [5], a well-known and high-quality 3D GAN. Our approach is simple yet effective and is based on the discovery of a specific latent space within EG3D, which we call the canonical latent space $\mathcal{W}_c$ . We find that latent codes belonging to this space can produce human faces with superior 3D shape and texture quality following two principles. Firstly, the input pose before the mapping network of EG3D must be a static canonical pose throughout the generation process. Secondly, the depth of the background should fall within a fixed range. Based on this, we propose using an encoder to invert the image into this canonical latent space using a proposed latent code discriminator and depth regularization. Although our encoder produces a suitable latent code that preserves the reasonable 3D shape of the input image, but the code is low dimension, making it challenging to capture texture details. To address this, similar to the 2D GAN inversion [3, 45], we refine the selected features in EG3D based on the residual between the input image and reconstruction image with predicted latent code. Meanwhile, we also find there is a canonical feature space $\mathcal{F}_c$ in EG3D, so we design an alignment module to project the refined feature to the canonical feature space. Moreover, we introduce an occlusion-aware fusion operation to avoid texture and shape distortions in reconstructing invisible regions. + +We conduct comprehensive experiments to evaluate the efficiency and effectiveness of our method, and the results demonstrate that our method achieves high-quality inversion comparable to optimization-based methods and superior to other encoder-based methods. We also demonstrate our approach is effective in 3D-aware editing applications. + +See Fig. 1 for some examples of inversion and editing of human portraits and cat faces obtained by our method. Our contribution can be summarised as following: + +- We conduct an exploration on the latent space and feature space of EG3D and discover the presence of a canonical attribute. +- Based on our analysis of the characteristics of the canonical latent space, we propose a geometry-aware encoder by utilizing a canonical latent discriminator and depth regularization. +- We introduce an alignment module based on the canonical feature space and an occlusion-aware method to refine the selected features of the generator and supplement high-quality details. +- The proposed method exhibits competitive performance with existing methods in human portraits, both qualitatively and quantitatively. Additionally, our method can also generalize to the cat faces and is effective in 3D editing tasks. + +# 2. Related Work + +# 2.1. Generative 3D-Aware Image Synthesis. + +Generative Adversarial Network [13] made significant advancements in generating both 2D photorealistic images [19, 20] and 3D-Aware consistent images. In 3D-aware image generation, some works build 3D GAN based on explicit 3D representations, such as point-cloud [41], voxel [28, 29, 43], and mesh [12, 15, 17]. However, these models often fail to generate high-resolution 3D scenes with high-quality details. + +Since NeRF [27] achieved outstanding multi-view image synthesis, a sequence of works has begun to use implicit 3D representation and volume rendering for 3D generation [5, 6, 10, 14, 30, 32]. Pi-GAN [6] is the first attempt at using GAN to generate NeRF for 3D-aware image synthesis. After that, StyleNeRF [14] proposes a view-consistent upsampling module to generate high-resolution images. StyleSDF [32] combines an SDF-based volume renderer and a 2D CNN network to obtain geometry information. GRAM [10] introduces 2D manifolds to regulate point sampling strategy in volume rendering. EG3D [5] leverages StyleGAN2 [20]'s structure and designs a computationally efficient 3D representation called tri-plane. It can synthesize high-resolution view-consistent images and produces high-quality 3D geometry. We explore EG3D's latent space and build our inversion encoder based on EG3D. + +# 2.2. GAN Inversion + +GAN Inversion is an inverse process of the generation that projects the given image to corresponding latent code for faithful reconstruction from the source image. Thus, + +![](images/dd8a273f71849cc80a28a40c177d163c1ab973c17154fd15b150f6595884c7f2.jpg) +Figure 2: Recap of EG3D. $z, p$ denotes a Gaussian sample and a pose condition. The relation of $w, F$ , and tri-plane is illustrated. + +the image editing process can be conducted by semantic editing on the latent code [33, 37, 51]. In 2D GAN, inversion methods are mainly divided into three categories. Optimization-based methods [1, 8, 46] optimize the generator's latent code or parameters both, achieve high reconstruction quality, but are time-consuming. Encoder-based methods [2, 35, 42] train an encoder to project input images to the latent codes. These methods can get faster inference than optimization-based methods but unsatisfactory inversion fidelity. Hybrid methods [4, 36, 51] use an encoder to get a latent as initialization, then optimize the latent code and generator parameters, which is still time-consuming. + +Unlike 2D methods, 3D GAN Inversion should also consider multi-view-consistence. Directly transferring 2D methods to the 3D inversion is prone to suffering geometry collapse and artifacts. To solve it, Pose Opt. [21] jointly optimizes camera pose, latent codes, and generator parameters. HFGI3D [47] is an optimization-based method that extracts mesh to create pseudo-multi-view supervision. Meanwhile, encoder methods are also gradually developing. IDE-3D [40] uses semantic segmentation to re-train EG3D and learns an encoder for inversion to edit images. NeRF-3DE [23] uses identity contrastive learning to train a based encoder and then trains a refining encoder for better details. E3DGE [22] trains a base encoder to learn coarse shape and texture and supplements local details with pixel-aligned features. However, existing encoder-based methods [22, 23] rely on synthetic paired data and may not generalize well to real-world scenarios. None of the state-of-the-art methods can handle time efficiency and 3D inversion quality simultaneously. + +# 3. EG3D Exploration + +In this section, we first briefly review the EG3D model. Then, we explore and analyze the properties of latent space and feature space in EG3D. + +The pipeline of EG3D is shown in Fig 2. It first combines a Gaussian vector $z$ and a pose condition $p$ as input and builds a mapper to generate a latent code $w$ , this process can be denoted as $w = \text{mapping}(z, p)$ . Then this latent code $w$ will be sent to each layer of a style-based hierarchical gen + +erator to obtain the feature maps $F$ . These feature maps are enlarged layer by layer. The last layer's feature map reshape to tri-plane, an efficient 3D representation consists of three axis-aligned feature planes $(F_{xy}, F_{xz}, F_{yz})$ . With this efficient 3D representation, EG3D samples point features from the tri-plane to synthesize multi-view images or depths by a rendering decoder $R_{dec}$ with volume rendering [27]. Similar to the 2D GAN, the latent code $w$ belongs to a latent space $\mathcal{W}$ , and all feature maps in the generator construct the $\mathcal{F}$ space. + +# 3.1. Canonical Latent Space $\mathcal{W}_c$ + +In order to investigate the properties of the latent space $\mathcal{W}$ and its relationship with pose conditioning, we adopt a fixed $z$ and sample various pose conditions to generate corresponding latent code $w$ . Fig. 3 illustrates that when $w$ is conditioned on an unsuitable pose $p$ far away from the canonical pose, the generated 3D shapes fail to generalize to other views synthesis. Only when the pose condition is canonical can the synthesized images maintain shape and texture consistency across multiple views. Meanwhile, we find a clear depth gap between the face and background regions when generating good results with the canonical pose condition. Under canonical pose, the depth of the background is restricted to a fixed range, while the face and background regions are confused for the other pose conditions. + +These observations lead us to identify a specific subspace of $\mathcal{W}$ intuitively, which we call canonical latent space, denoted as $\mathcal{W}_c$ , that is responsible for ensuring reasonable 3D shape and texture across multiple views. There are two principles of this canonical latent space. Firstly, the input pose before the mapping network of EG3D must be a static canonical pose. Secondly, the depth of the background should fall within a fixed range to distinguish the face and background regions. Based on these findings, we propose that a high-quality 3D-GAN inversion method should first retrieve a $w$ latent code in $\mathcal{W}_c$ to ensure the best possible image synthesis results. + +# 3.2. Canonical Feature Space $\mathcal{F}_c$ + +To analyze the characteristics of $\mathcal{F}$ space, we generate the latent codes with different pose conditions to synthesize multiple tri-planes. We visualize the tri-plane as illustrated in Fig 3. The tri-plane also represents a canonical view when the pose condition is canonical (i.e., the columns $\mathrm{g} \sim \mathrm{i}$ in row $\mathrm{L}_2$ ). It indicates that there is also a specific subspace of $\mathcal{F}$ , we call it canonical feature space, denoted as $\mathcal{F}_c$ , and the canonical latent space $\mathcal{W}_c$ produces the canonical feature space $\mathcal{F}_c$ with the generator layers. The $\mathcal{F}_c$ can supply sufficient facial information for rendering multi-view images. + +![](images/de5cd014efd237fc56102bee1b6e8ef4ca24f9fb81acddfdcfe8d6b23a5a3ee9.jpg) +Figure 3: Illustration of canonical Pose condition. We synthesize multi-view images for three pose conditions $p$ , including left, right, and canonical. As shown in a $\sim$ c, the canonical pose condition in row $L_2$ has no distortion face shape. Moreover, depth maps in row $L_2$ demonstrate that images on the canonical pose condition have significant foreground and background differences. In contrast, flattened shape depth maps in rows $L_1$ and $L_3$ have foreground and background confusion. Columns $g \sim i$ reveal the tri-plane is also related to the pose condition. + +![](images/2a8c83275cf93259cce48a9c9c7a81e64fc91c8b5a1253cf572403cd3a7983d2.jpg) + +![](images/dbccfbbc7ec4150e734c740ab84ba1015919e167031e77aa31ecd59b4d154d8c.jpg) + +# 4. Method + +The pipeline of our method is shown in Fig. 4. We first project the input image $I$ to the latent code $w^{+} \subset \mathbb{R}^{14 \times 512}$ with our encoder, where $w^{+} = (w_{0}, w_{1}, \dots, w_{13})$ is an extension of latent code $w$ and can preserve the details better as mentioned in 2D GAN inversion [35, 42]. Then we calculate the residual between $I$ and the generated image $I_{w^{+}}$ based on $w^{+}$ to refine the features of the generator. In the following Sec. 4.1 and Sec. 4.2, we will describe how we ensure the latent code $w^{+}$ and refined feature belong to the canonical space, respectively. Furthermore, we introduce an occlusion-aware mix tri-plane in Sec. 4.3 to avoid the distortion of invisible regions reconstruction. In Sec. 4.4, we exhibit how to perform 3D semantic editing with our inversion method. + +# 4.1. Geometry-aware Encoder + +We design a geometry-aware encoder to obtain the latent code $w^{+}$ given the input image $I$ and corresponding rendering camera pose $c$ . We generate the inverted latent code $w^{+}$ according to the backbone's pyramid feature progressively. It is worth noting that we choose Swin-transformer [25] as the backbone and further add attention modules at different scale feature layers for different level latent codes (more details of encoder architecture are in supplementary materials). After projecting the input image to the latent code $w^{+}$ , we can synthesize the tri-plane $w^{+}$ through EG3D generator $G$ and use rendering decoder $R_{dec}$ to get the reconstruction image $I_{w^{+}}$ under the rendering camera pose $c$ . + +$$ +w ^ {+} = E (I), \tag {1} +$$ + +$$ +I _ {w ^ {+}} = R _ {d e c} (G (w ^ {+}), c) +$$ + +To make the inverted $w^{+}$ not deviate far from the canonical space $\mathcal{W}_c$ discussed in Sec. 3.1, we use a canonical latent discriminator [31] to discriminate between $w_{c} \in \mathcal{W}_{c}$ and $w^{+}$ . The canonical latent discriminator, denoted as $\mathcal{D}_{\mathcal{W}_c}$ , is trained in an adversarial scheme with the non-saturating GAN loss [13] and $R_{1}$ regularization [26], the loss of adversarial learning process can be written as below: + +$$ +\begin{array}{l} \mathcal {L} _ {\mathrm {a d v}} ^ {\mathcal {D} \mathcal {W} _ {c}} = - \mathbb {E} [ \log \mathcal {D} _ {\mathcal {W} _ {c}} (w _ {c}) ] - \mathbb {E} [ \log (1 - \mathcal {D} _ {\mathcal {W} _ {c}} (w _ {i})) ] (2) \\ + \frac {\gamma}{2} \mathbb {E} \left[ \| \nabla \mathcal {D} _ {\mathcal {W} _ {c}} \left(w _ {c}\right) \| _ {2} \right], \\ \mathcal {L} _ {\mathrm {a d v}} ^ {E} = - \mathbb {E} \left[ \log \mathcal {D} _ {\mathcal {W} _ {c}} \left(w _ {i}\right) \right], (3) \\ \end{array} +$$ + +where $\gamma$ is the weight of $R_{1}$ regularization, the $\mathcal{L}_{\mathrm{adv}}^{\mathcal{D}_{\mathcal{W}_c}}$ and $\mathcal{L}_{\mathrm{adv}}^{E}$ are the loss for the latent discriminator $\mathcal{D}_{\mathcal{W}_c}$ and encoder respectively. $\mathcal{D}_{\mathcal{W}_c}$ operates on $w_{c}$ and each entry $w_{i}$ of $w^{+}$ . + +As discussed in Sec. 3.1, the background depth of an integrated face should be limited in a range. To estimate the background depth, we first random sample 0.1 million front images with the canonical pose condition, then we obtain the depth maps and background regions of these images. We use the parsing method [52] to get a binary mask $M$ where $M = 1$ indicates the background region and 0 otherwise. Finally, we calculate the average depth $D_{avg}$ of background regions of these samples, and we set the $D_{avg}$ as a regularization to constrain the background depth during inversion, the background regularization can be written as below: + +$$ +\mathcal {L} _ {B G} = \left\| D \odot M - D _ {\text {a v g}} \odot M \right\| _ {2}. \tag {4} +$$ + +![](images/27ea64ea00de07ed3c1a11bf130ff831174d290515212f0bdfb90d8307e367ab.jpg) +Figure 4: Overview of our method. Our framework could be divided into two parts. (1) $\mathcal{W}$ space inversion. We design an encoder $E$ to invert input image $I$ into $w^{+}$ latent codes. The $w^{+}$ latent codes are fed into a pre-trained EG3D generator $G$ to get tri-plane $_{w^{+}}$ and rendered into reconstruction image $I_{w^{+}}$ . (2) Complement the $\mathcal{F}$ space. We calculate the image residual $\Delta I$ between the input image and its reconstruction and propose AFA module to refine the F latent maps. The modified latent maps $F^{*}$ are transformed into tri-plane $_{mix}$ by occlusion-aware mix and rendered into the fine detailed inversion image $I_{F^{*}}$ . + +Here, $D$ and $M$ are the depth map and background mask inverted image under the front-view pose. + +In addition, we use reconstruction loss function $\mathcal{L}_{rec}$ follow pSp [35] in the training stage. The $\mathcal{L}_{rec}$ is composed by pixel-wise $\mathcal{L}_2$ loss, perceptual loss $\mathcal{L}_{LPIPS}$ [50], and facial identity similarity loss $\mathcal{L}_{ID}$ with pre-trained ArcFace network [9]: + +$$ +\mathcal {L} _ {r e c} = \left\| I _ {w ^ {+}} - I \right\| _ {2} + \mathcal {L} _ {L P I P S} \left(I _ {w ^ {+}}, I\right) + \mathcal {L} _ {I D} \left(I _ {w ^ {+}}, I\right). \tag {5} +$$ + +# 4.2. Adaptive Feature Alignment + +It is non-trivial to restore fine-detailed texture with only a highly compressed $w$ latent code. Thus, adjusting high-dimension feature maps in the $\mathcal{F}$ space is natural to achieve high-fidelity inversion as mentioned in related 2D GAN inversion methods [3, 11, 45]. Moreover, it is worth noting that the feature maps $F$ generated with our inverted $w^{+}$ are in the canonical feature space $\mathcal{F}_c$ . + +We calculate the residual $\Delta I$ between $I$ and $I_{w^{+}}$ and hope to refine the feature maps to eliminate this residual. However, directly setting the residual as input and predicting the refined feature maps with a CNN to modify $F$ is invalid. This is because the residual is highly entangled with the view of the input image, while $F$ is in $\mathcal{F}_c$ . When the view is not canonical, the refined feature maps with this residual can not project to the $\mathcal{F}_c$ space simply. Thus, aligning the residual feature maps to the $\mathcal{F}_c$ space is necessary to synthesize high-quality images, as mentioned in Sec. 3.2. + +According to the above analysis, we propose an adaptive feature alignment (AFA) module that enables automatic canonical space alignment by cross-attention mechanism, as shown in Fig 5. First, we use a CNN to capture the feature $F_{\Delta I}$ of $\Delta I$ , and we take $F_{\Delta I}$ as the key $K$ , value $V$ , and the feature map $F$ as a query $Q$ . Then, we utilize cross-attention modules to align the $F_{\Delta I}$ with $F$ and output a feature $F_{\text{align}}$ . Since the $F$ is already in the canonical feature + +![](images/2dbb1e67ed2d33a6228061091285998fc37361098f40d10f876460efa53932b4.jpg) +Figure 5: The Architecture of AFA Module. We use a CNN to capture the feature $F_{\Delta I}$ of residual image $\Delta I$ , and align the $F_{\Delta I}$ to $F$ with cross attention module. Finally, we refine the $F$ with the aligned feature $F_{\text{align}}$ . + +space $\mathcal{F}_c$ , and the feature $F_{align}$ can also have the properties of $\mathcal{F}_c$ space. Finally, we use the $F_{align}$ to predict the scale map $\gamma$ and translation map $\beta$ to refine the $F$ with Feature-wise Linear Modulation (FiLM) [34]. The whole process of our AFA module can be formulated as follows: + +$$ +F _ {\Delta I} = C N N (\Delta I), +$$ + +$$ +Q, K, V = W _ {Q} F, W _ {K} F _ {\Delta I}, W _ {V} F _ {\Delta I}, +$$ + +$$ +F _ {\text {a l i g n}} = \text {A t t e n t i o n} (Q, K, V), \tag {6} +$$ + +$$ +\gamma , \beta = C o n v _ {\gamma} (F _ {a l i g n}), C o n v _ {\beta} (F _ {a l i g n}), +$$ + +$$ +F ^ {*} = \gamma \odot F + \beta , +$$ + +where $W_{Q}, W_{K}, W_{V}$ are learnable projection heads and $d$ is the dimension of feature, the $F^{*}$ is the final output of our AFA module. With this adaptive alignment, we achieve a detailed complement of $\mathcal{F}_c$ space. Note that we adopt $\mathcal{L}_{total}$ and a $\mathcal{L}_2$ regularization loss on $\Delta F = F^{*} - F$ when training the AFA module. + +# 4.3. Occlusion-aware Mix Tri-plane + +The image residual $\Delta I$ only contains information in the visible area of the input view. Using single-view residuals to modify the entire $F$ will lead to distortion at the occlusion region. To solve this problem, we propose the Occlusion- + +aware Mix Tri-plane. + +The tri-plane contains all points in the 3D space which are divided into visible points set and occlusion points set according to the input view. Here, we define the 3D points viewed in the input image in tri-plane as the visible points set $\mathcal{V}_{(x,y,z)}$ , points in the occlusion regions as occlusion points set $\mathcal{O}_{(x,y,z)}$ . We can get the depth map $D$ under the input view, and the two points set can be defined by: + +$$ +\begin{array}{l} \mathcal {V} _ {(x, y, z)} = \left\{\left[ x, y, z \right] ^ {T}: \left[ x, y, z \right] ^ {T} = \pi D (u, v) \mathcal {K} ^ {- 1} \left[ u, v, 1 \right] ^ {T} \right\}, \\ \mathcal {O} _ {(x, y, z)} = \mathbb {R} ^ {3} \backslash \mathcal {V} _ {(x, y, z)}, \tag {7} \\ \end{array} +$$ + +where $[u,v,1]$ is the pixel homogeneous coordinate of the input image, $\pi$ is the extrinsic camera parameter matrix of the input view, $D(u,v)$ is the depth of pixel $[u,v]$ , $\mathcal{K}$ is the intrinsic camera parameter matrix. + +After determining the visible area, we can supplement the refined details of the input view to the tri-plane. We define the occlusion-aware mix tri-plane as follows: + +$$ +\begin{array}{l} \operatorname {t r i - p l a n e} _ {w ^ {+}} = G \left(w ^ {+}\right), \\ \operatorname {t r i - p l a n e} _ {F ^ {*}} = G \left(F ^ {*}\right), (8) \\ \left. \operatorname {t r i - p l a n e} _ {\text {m i x}} = \operatorname {t r i - p l a n e} _ {F ^ {*}} \right| _ {(x, y, z) \in \mathcal {V}} (6) \\ + \operatorname {t r i - p l a n e} _ {w +} | _ {(x, y, z) \in \mathcal {O}}, \\ \end{array} +$$ + +where $w^{+}$ is the latent code learned from the encoder, and $F^{*}$ is the refined feature map. Finally, we use tri-planes mix with rendering decoder to synthesize images under different views when inference. + +# 4.4. Editing + +To achieve 3D-consistent editing, we need to modify both $w^{+}$ and $F^{*}$ . We first get the edited latent code $\hat{w}^{+}$ through classic latent code editing methods [33, 37]. Then for $F^{*}$ , we follow FS [48] to extract the features $F^{\hat{w}^{+}}$ and $F^{w}$ from the generator convolution layer with input $\hat{w}^{+}$ and $w$ , respectively. Finally, we calculate the difference between these two features and add it to the $F^{*}$ to get the edited features $\hat{F^{*}}$ : + +$$ +\hat {F} ^ {*} = F ^ {*} + F ^ {\hat {w} ^ {+}} - F ^ {w}. \tag {9} +$$ + +With the modified $\hat{w}^{+}$ and $\hat{F}^{*}$ , we use the method in section 4.3 to get edited mix tri-plane, and use rendering decoder to synthesize 3D-consistent edited images. + +# 4.5. Losses. + +In the first training stage, we use the loss function mentioned in Sec 4.1. For the input view reconstruction, the loss $\mathcal{L}_{rec}$ is computed by: + +$$ +\mathcal {L} _ {r e c} = \lambda_ {1} \| I _ {w ^ {+}} - I \| _ {2} + \lambda_ {2} \mathcal {L} _ {L P I P S} \left(I _ {w ^ {+}}, I\right) + \lambda_ {3} \mathcal {L} _ {I D} \left(I _ {w ^ {+}}, I\right), \tag {10} +$$ + +where $\lambda_{1} = 1.0, \lambda_{2} = 0.8, \lambda_{3} = 0.25$ . The total loss for training our encoder and the canonical latent discriminator can be written as: + +$$ +\mathcal {L} _ {\text {t o t a l}} ^ {E} = \mathcal {L} _ {\mathrm {a d v}} ^ {\mathcal {D} w _ {c}} + \lambda_ {4} \mathcal {L} _ {\mathrm {a d v}} ^ {E} + \lambda_ {5} \mathcal {L} _ {B G} + \mathcal {L} _ {\text {r e c}}, \tag {11} +$$ + +where $R_{1}$ regularization weight $\gamma = 10$ , $\lambda_4 = 0.05$ , $\lambda_5 = 5.0$ . Moreover, we apply regularization on $\Delta w^{+} = (w_{1} - w_{0}, w_{2} - w_{0}, \dots, w_{13} - w_{0})$ by $\mathcal{L}_2$ norm, i.e. $\mathcal{L}_{w^+} = \lambda_6\| \Delta w^+\|_2$ , where $\lambda_6 = 0.001$ . + +Once the loss in the first stage is converged, we freeze the encoder parameters and drop the canonical latent discriminator and losses $\mathcal{L}_{\mathrm{adv}}^{\mathcal{D}_{\mathcal{W}_c}},\mathcal{L}_{\mathrm{adv}}^E,\mathcal{L}_{w^+}$ , but add a $\mathcal{L}_2$ regularization on $\Delta F = F^{*} - F$ with $\lambda_7 = 0.0001$ for training the AFA module, i.e. $\mathcal{L}_{\Delta F} = \lambda_7\| \Delta F\| _2$ . We apply the loss settings to both human data and cat data. + +For re-implemented pSp [35] and e4e [42], we train it with the same loss weight in our settings, and train them until the losses converge. + +# 5. Experiments + +Experiment setup. We evaluate our method on human faces and cat faces. For human faces, we use FFHQ [1] dataset for training, and CelebA-HQ [18] and MEAD [44] for evaluation. For the cat faces, we use AFHQ-CAT [7] for training and evaluation. In addition, we employ the pretrained EG3D generator and obtain the corresponding camera parameters of each image following the official implementation in EG3D. + +Baselines. We compare our method with encoder (IDE-3D [40]) and optimization-based (PTI [36] and Pose Opt. [21]) baselines in these two aspects. Moreover, we build two encoder baselines imitating the state-of-the-art StyleGAN inverters, pSp [35] and e4e [42], and present the model structure in the supplementary. + +# 5.1. Qualitative analysis + +Source View Inversion Results. Fig. 6 shows the inversion performance comparison between ours and other methods. Our method's hair details and facial similarity are obviously competitive with optimization methods and surpass all the encoder-based methods. + +Novel View Synthesis Results. The comparison results are shown in Fig. 6. Inspecting the eye gaze direction and person's identity preservation when changing to novel views can reveal the differences. It can be seen that on some extreme side-face camera poses, some optimization methods produce artifacts and geometry distortions. Our method can keep synthesizing 3D-consistent images faithful to the person's identity in the input. + +# 5.2.Quantitative analysis + +We calculate the mean square error (MSE), LPIPS [50], and FID [16] between the source image and its inversion. + +![](images/e2aedef42d3dfd5ad3f27e244d833b216f9797f8614bd06b88fc97cd5145c3ef.jpg) +Figure 6: Visual comparison of inversion and novel-view synthesized results between our method and others. Our method surpasses all the encoder-based methods and is competitive with optimization methods in recovering texture details, i.e., our method prevents the eye orientation from changing with the camera view and artifacts in the novel view. + +
CategoryMethodReconstruction QualityNovel View Quality
Input Viewyaw=±60°yaw=0°
MSE ↓LPIPS ↓FID ↓ID ↑Geo. Err. ↓Time (s) ↓LPIPS ↓FID ↓ID ↑Geo. Err. ↓LPIPS ↓FID ↓ID ↑Geo. Err. ↓
OptimizationPTI [36]0.01630.091818.00.84170.0850115.20.292669.80.6210.14810.192553.50.7180.1006
Pose Opt. [21]0.01640.087917.50.83900.0759219.70.44771320.3210.17630.243660.20.6050.1504
Encoder-basedIDE-3D [40]0.10560.280643.60.71940.18350.06590.331779.00.5050.29140.307463.70.5130.2528
pSp-3D [35]0.07260.208231.20.78170.18460.12840.322365.70.5910.12870.313265.20.6710.1789
e4e-3D [42]0.08080.228133.00.73590.11610.13030.249557.70.5880.12690.239453.80.6530.1305
Ours-w+0.06970.198130.90.78730.11000.09630.230352.20.6550.09430.237254.10.6850.0955
Ours0.03010.125720.50.87520.09870.22620.219250.90.7000.09500.220451.70.7430.0944
+ +Table 1: Comparison with state-of-the-art methods on inversion performance. The numbers in bold are the best performance of the optimization and encoder-based methods, respectively. Metrics of Reconstruction Quality are calculated under the input view. Metrics of Novel View Quality are the average of multi-view. The yaw angle is the source view angle. + +We adopt a pre-trained face key point detector parsenet [52] to calculate the identity similarity. To measure the geometry properties, we followed [5, 38], utilizing a pre-trained 3D face reconstruction model to extract a "pseudo" ground truth depth map from the source image. Then, we obtain the depth of inversion and normalize all depth maps to zero means and unit variance to calculate geometry error (Geo. Err.) by using average $\mathcal{L}_2$ distance. + +Source View Inversion Results. Table 1 presents the quantitative comparison of the input view image reconstruction on CelebA-HQ test dataset. Our method is two orders of magnitude faster than the optimized methods with similar + +performance, which is notably better than other encoder-based methods. + +Novel View Synthesis Results. In order to measure the multi-view consistency and the synthesized quality, we evaluate our method and baselines with a multi-view dataset, MEAD [44]. Each person in MEAD has five images with increasing yaw angles. We select one angle as the input view, invert the input image and synthesize the other four novel views. Then we use the same metrics to calculate the difference between the synthesized images and the ground truth. The quantitative comparison between the novel view synthesized results and the ground truth in dif + +![](images/afc3c8a45e15f98589850b01d19d5a8f464c0808a207e00edd3903f4754095cb.jpg) +Figure 7: Ablation of Geometry-aware Encoder. All images are synthesized only with $w^{+}$ . Without both modules, $w^{+}$ fails to generate integrated 3D geometry and texture. The $L_{BG}$ helps distinguish foreground and background. With $\mathcal{D}_{\mathcal{W}_c}$ , we can get good inversion under the input view but fail under the novel view. With both modules, $w^{+}$ can obtain an integrated side face of the woman, which is occlusion under the input view. + +ferent views is shown in Table 1. Our method shows similar performance with PTI when the input image is a front face $(\mathrm{yaw} = 0^{\circ})$ . When inverting side faces, the difficulty of inversion increases drastically when the yaw angle increases. We calculated the metrics of the largest yaw angle in MEAD $(\mathrm{yaw} = \pm 60^{\circ})$ , and our model has robust performance when the test yaw angle varies. However, the performance of optimization methods degrades remarkably at an extreme angle. + +# 5.3. Ablation Analysis + +We present ablation studies with qualitative analysis of our proposed method below, and the corresponding numerical ablation results are in our supplementary. + +Geometry-aware Encoder. We conduct ablation experiments and make qualitative comparisons to verify that our proposed canonical latent discriminator $(\mathcal{D}_{\mathcal{W}_c})$ and background regularization $(\mathcal{L}_{BG})$ contribute to restoring 3D geometry. Generally, recovering the geometry from a side face input is more challenging and we test such a case. As shown in Fig. 7, only if we adopt the canonical discriminator and the background regularization could we obtain a satisfactory foreground and background geometry. + +Adaptive Feature Alignment. We proposed Adaptive Feature Alignment (AFA) to refine the $F$ latent map and add texture details from the source view. Fig. 8 demonstrates that we can recover more details with AFA. + +Occlusion-aware Mix Tri-plane. To verify the necessity of our proposed occlusion-aware mix tri-plane, we ablate this operation and visualize the novel view results in Fig. 9. The occlusion map shows the spatial position of surface points + +![](images/02bd75f9518dbefc9cff5c37265c55a26824a8b6103f1a00864d81db79de6410.jpg) +Figure 8: Ablation of Adaptive Feature Alignment. We replace AFA with a CNN network and obtain the results. Without feature alignment, it is difficult to reconstruct the hair and facial details. + +![](images/7adb34605baa08408b4fc2ea44bd3c6b22a1997e5a1bd72712d05fc7125d63f5.jpg) + +![](images/bd1412f2e7b937d752ef20e257b2b0a8f83c0ed011341d344c2e8dc0ad8182e6.jpg) +Figure 9: Ablation of Occlusion-aware mix tri-plane. We visualize the occlusion regions $\mathcal{O}_{(x,y,z)}$ of the input view in the last column (black points). The green arrow points out $\mathcal{O}_{(x,y,z)}$ in the novel view, and it is obvious that the occlusion-aware mix tri-plane can avoid artifacts. + +![](images/c1f26b2e765a19c8c7b24a1e0582fe0bcbc967fa3d287666524b2c8a77e89703.jpg) +Figure 10: Editing result under novel views. We add three different attributes to three faces. Our method generates both realistic editing and 3D-consistent novel views. + +in ray sampling, the visible region in the original view is white, and the occlusion region is black. Without the mix tri-plane, the occlusion area from the source view is easy to produce artifacts in novel views. + +# 5.4. Image Editing Results + +In GAN inversion-based image manipulation, the editability and the reconstruction trade-off widely exists in both 2D and 3D scenarios. We validate the editing method + +![](images/dd3ce5e5ff80b88a81039421bb32462b9379d2ceb475a8b1590846ef195aa0ee.jpg) +Figure 11: Results of our encoder in other 3D GANs. + +
MSE ↓LPIPS ↓FID ↓MSE ↓LPIPS ↓FID ↓
w/o AFA0.05860.231713.43w/ AFA0.03670.174510.82
+ +Table 2: Ablation of AFA on ShapeNet Cars. + +mentioned in Sec. 4.4 and display the multi-view edited results in Fig. 10. We choose three different edit directions, 'Young' to reduce person's age, 'Unhappy' to change emotion, and 'Glasses' to add accessories. It is noticeable that our method not only restores the geometric and texture information of the input image but also ensures the editing consistency of multi-view. The edited results demonstrate that our inversion method can be well applied to the facial image editing tasks. + +![](images/6b816134e4a44946b9b5ed091e2151b5ae6970cbc52852231505cebbc2bab88b.jpg) +Figure 12: (a) Tri-plane canonical feature space. (b) Results of our method on ShapeNet Cars datasets. Best viewed zoomed in and in color. + +# 6. Generalization + +Our method can be adapted to other 3D GANs (e.g., EpiGRAF [39] and StyleSDF [32]) and it works also with categories where pose estimation and canonicalization are more difficult (e.g., Shapenet cars). + +Extension to other 3D GANs. We choose EG3D as our base 3D GAN due to its superior performance, but our method can also be applied to other 3D GANs. The canon- + +ical space, which plays a vital role in 3D GAN inversion, is commonly presented in the latent space (i.e., $w^{+}$ space) of 3D GANs. By inverting images into the canonical space, we preserve geometry and achieve high-fidelity reconstruction, as demonstrated in our experiments on EpiGRAF [39] and StyleSDF [32] in Fig. 11. The results of w/o $\mathcal{D}_{\mathcal{W}_c}, L_{BG}$ mean that we only use the base encoder without the canonical latent discriminator and the background depth regularization. In contrast, w/ $\mathcal{D}_{\mathcal{W}_c}, L_{BG}$ is our full encoder model. The noticeable performance gap proves the powerful inversion ability of our method. Our method explores the canonical space's characteristics, ensuring distortion-free shape generation and exceptional performance in image 3D inversion. + +Extension to ShapeNet Cars. Fig. 12 shows (a) the canonical space and (b) the inversion results on ShapeNet Cars. Even without identity loss, our method can achieve good performance(see the Col.3,5 of (b)). As the tri-plane is canonical, without the AFA module, the residual feature can not align with the canonical feature space (see the Col. 2,4 of (b) and Table 2). + +# 7. Conclusion + +In this work, we explore the inherent property of EG3D's latent space and find that the key to achieve high-quality shape and texture inversion is inverting input images to the canonical space. In light of this, we design an efficient geometry-aware encoder with an adaptive feature alignment module and demonstrate their effectiveness. Besides, we propose an occlusion-aware mix tri-plane to avoid invisible region distortion in novel views. Extensive experiments demonstrate that our method has competitive inversion performance with optimization-based methods, but operates two orders of magnitude faster. In addition, our method is demonstrated to be a powerful tool for realistic and 3D view-consistent editing of facial images. + +# 8. Acknowledgement + +This work was supported by the National Key R&D Program of China (2022YFB4701400/4701402), SZSTC Grant (JCYJ20190809172201639, WDZC20200820200655001), Shenzhen Key Laboratory (ZDSYS20210623092001004), and Beijing Key Lab of Networked Multimedia. + +# References + +[1] Rameen Abdul, Yipeng Qin, and Peter Wonka. Image2stylegan: How to embed images into the stylegan latent space? In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4432-4441, 2019. 3, 6 +[2] Yuval Alaluf, Or Patashnik, and Daniel Cohen-Or. Restyle: A residual-based stylegan encoder via iterative refinement. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6711–6720, 2021. 3 +[3] Yuval Alaluf, Omer Tov, Ron Mokady, Rinon Gal, and Amit Bermano. Hyperstyle: Stylegan inversion with hypernetworks for real image editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18511-18521, 2022. 2, 5 +[4] Lucy Chai, Jun-Yan Zhu, Eli Shechtman, Phillip Isola, and Richard Zhang. Ensembling with deep generative views. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14997-15007, 2021. 3 +[5] Eric R Chan, Connor Z Lin, Matthew A Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas J Guibas, Jonathan Tremblay, Sameh Khamis, et al. Efficient geometry-aware 3d generative adversarial networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 16123-16133, 2022. 1, 2, 7 +[6] Eric R Chan, Marco Monteiro, Petr Kellnhofer, Jiajun Wu, and Gordon Wetzstein. pi-gan: Periodic implicit generative adversarial networks for 3d-aware image synthesis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5799-5809, 2021. 1, 2 +[7] Yunjoy Choi, Youngjung Uh, Jaejun Yoo, and Jung-Woo Ha. Stargan v2: Diverse image synthesis for multiple domains. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8188-8197, 2020. 6 +[8] Edo Collins, Raja Bala, Bob Price, and Sabine Susstrunk. Editing in style: Uncovering the local semantics of gans. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5771-5780, 2020. 3 +[9] Jiankang Deng, Jia Guo, Niannan Xue, and Stefanos Zafeiriou. Arcface: Additive angular margin loss for deep face recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4690-4699, 2019. 5 +[10] Yu Deng, Jiaolong Yang, Jianfeng Xiang, and Xin Tong. Gram: Generative radiance manifolds for 3d-aware image generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10673-10683, 2022. 2 +[11] Tan M Dinh, Anh Tuan Tran, Rang Nguyen, and Binh-Son Hua. Hyperinverter: Improving stylegan inversion via hypernetwork. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11389-11398, 2022. 2, 5 +[12] Shubham Goel, Angjoo Kanazawa, and Jitendra Malik. Shape and viewpoint without keypoints. In European Conference on Computer Vision, 2020. 2 +[13] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and + +Yoshua Bengio. Generative adversarial nets. In Advances in Neural Information Processing Systems, 2014. 2, 4 +[14] Jiatao Gu, Lingjie Liu, Peng Wang, and Christian Theobalt. Stylenerf: A style-based 3d-aware generator for high-resolution image synthesis. arXiv preprint arXiv:2110.08985, 2021. 1, 2 +[15] Paul Henderson, Vagia Tsiminaki, and Christoph H Lampert. Leveraging 2d data to learn textured 3d mesh generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. 2 +[16] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in Neural Information Processing Systems, 30, 2017. 6 +[17] Angjoo Kanazawa, Shubham Tulsiani, Alexei A. Efros, and Jitendra Malik. Learning category-specific mesh reconstruction from image collections. In European Conference on Computer Vision, 2018. 2 +[18] Tero Karras, Timo Aila, Samuli Laine, and Jaakko Lehtinen. Progressive growing of GANs for improved quality, stability, and variation. In International Conference On Learning Representations, 2018. 6 +[19] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2019. 2 +[20] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of StyleGAN. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2020. 2 +[21] Jaehoon Ko, Kyusun Cho, Daewon Choi, Kwangrok Ryoo, and Seungryong Kim. 3d gan inversion with pose optimization. arXiv preprint arXiv:2210.07301, 2022. 1, 3, 6, 7 +[22] Yushi Lan, Xuyi Meng, Shuai Yang, Chen Change Loy, and Bo Dai. Self-supervised geometry-aware encoder for style-based 3d gan inversion. arXiv preprint arXiv:2212.07409, 2022. 2, 3 +[23] Yu-Jhe Li, Tao Xu, Bichen Wu, Ningyuan Zheng, Xiaoliang Dai, Albert Pumarola, Peizhao Zhang, Peter Vajda, and Kris Kitani. 3d-aware encoding for style-based neural radiance fields. arXiv preprint arXiv:2211.06583, 2022. 2, 3 +[24] Hongyu Liu, Yibing Song, and Qifeng Chen. Delving stylegan inversion for image editing: A foundation latent space viewpoint. arXiv preprint arXiv:2211.11448, 2022. 2 +[25] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10012-10022, 2021. 4 +[26] Lars Mescheder, Andreas Geiger, and Sebastian Nowozin. Which training methods for gans do actually converge? In International Conference on Machine Learning, pages 3481-3490. PMLR, 2018. 4 +[27] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: + +Representing scenes as neural radiance fields for view synthesis. In European Conference on Computer Vision, 2020. 1, 2, 3 +[28] Thu Nguyen-Phuoc, Chuan Li, Lucas Theis, Christian Richardt, and Yong-Liang Yang. Hologan: Unsupervised learning of 3d representations from natural images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7588-7597, 2019. 2 +[29] Thu H Nguyen-Phuoc, Christian Richardt, Long Mai, Yongliang Yang, and Niloy Mitra. Blockgan: Learning 3d object-aware scene representations from unlabelled images. Advances in Neural Information Processing Systems, 33:6767-6778, 2020. 2 +[30] Michael Niemeyer and Andreas Geiger. Giraffe: Representing scenes as compositional generative neural feature fields. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11453-11464, 2021. 2 +[31] Yotam Nitzan, Amit Bermano, Yangyan Li, and Daniel Cohen-Or. Face identity disentanglement via latent space mapping. arXiv preprint arXiv:2005.07728, 2020. 4 +[32] Roy Or-El, Xuan Luo, Mengyi Shan, Eli Shechtman, Jeong Joon Park, and Ira Kemelmacher-Shlizerman. Stylesdf: High-resolution 3d-consistent image and geometry generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13503–13513, 2022. 1, 2, 9 +[33] Or Patashnik, Zongze Wu, Eli Shechtman, Daniel Cohen-Or, and Dani Lischinski. Styleclip: Text-driven manipulation of stylegan imagery. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2085–2094, 2021. 3, 6 +[34] Ethan Perez, Florian Strub, Harm De Vries, Vincent Dumoulin, and Aaron Courville. Film: Visual reasoning with a general conditioning layer. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 32, 2018. 5 +[35] Elad Richardson, Yuval Alaluf, Or Patashnik, Yotam Nitzan, Yaniv Azar, Stav Shapiro, and Daniel Cohen-Or. Encoding in style: a stylegan encoder for image-to-image translation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2287–2296, 2021. 3, 4, 5, 6, 7 +[36] Daniel Roich, Ron Mokady, Amit H Bermano, and Daniel Cohen-Or. Pivotal tuning for latent-based editing of real images. ACM Transactions on Graphics (TOG), 42(1):1-13, 2022. 3, 6, 7 +[37] Yujun Shen, Jinjin Gu, Xiaou Tang, and Bolei Zhou. Interpreting the latent space of gans for semantic face editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9243-9252, 2020. 3, 6 +[38] Yichun Shi, Divyansh Aggarwal, and Anil K Jain. Lifting 2d stylegan for 3d-aware face generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6258-6266, 2021. 7 +[39] Ivan Skorokhodov, Sergey Tulyakov, Yiqun Wang, and Peter Wonka. Epigraph: Rethinking training of 3d gans. arXiv preprint arXiv:2206.10535, 2022. 9 + +[40] Jingxiang Sun, Xuan Wang, Yichun Shi, Lizhen Wang, Jue Wang, and Yebin Liu. Ide-3d: Interactive disentangled editing for high-resolution 3d-aware portrait synthesis. arXiv preprint arXiv:2205.15517, 2022. 3, 6, 7 +[41] Maxim Tatarchenko, Alexey Dosovitskiy, and Thomas Brox. Multi-view 3D models from single images with a convolutional network. In European Conference on Computer Vision, 2016. 2 +[42] Omer Tov, Yuval Alaluf, Yotam Nitzan, Or Patashnik, and Daniel Cohen-Or. Designing an encoder for stylegan image manipulation. ACM Transactions on Graphics (TOG), 40(4):1-14, 2021. 2, 3, 4, 6, 7 +[43] Shubham Tulsiani, Hao Su, Leonidas J. Guibas, Alexei A. Efros, and Jitendra Malik. Learning shape abstractions by assembling volumetric primitives. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2017. 2 +[44] Kaisiyuan Wang, Qianyi Wu, Linsen Song, Zhuoqian Yang, Wayne Wu, Chen Qian, Ran He, Yu Qiao, and Chen Change Loy. Mead: A large-scale audio-visual dataset for emotional talking-face generation. In European Conference on Computer Vision, pages 700–717. Springer, 2020. 6, 7 +[45] Tengfei Wang, Yong Zhang, Yanbo Fan, Jue Wang, and Qifeng Chen. High-fidelity gan inversion for image attribute editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11379-11388, 2022. 2, 5 +[46] Zongze Wu, Dani Lischinski, and Eli Shechtman. Stylespace analysis: Disentangled controls for stylegan image generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12863-12872, 2021. 3 +[47] Jiaxin Xie, Hao Ouyang, Jingtan Piao, Chenyang Lei, and Qifeng Chen. High-fidelity 3d gan inversion by pseudomulti-view optimization. arXiv preprint arXiv:2211.15662, 2022.1.3 +[48] Xu Yao, Alasdair Newson, Yann Gousseau, and Pierre Hellier. A style-based gan encoder for high fidelity reconstruction of images and videos. European Conference on Computer Vision, 2022. 6 +[49] Fei Yin, Yong Zhang, Xuan Wang, Tengfei Wang, Xiaoyu Li, Yuan Gong, Yanbo Fan, Xiaodong Cun, Ying Shan, Cengiz Oztireli, et al. 3d gan inversion with facial symmetry prior. arXiv preprint arXiv:2211.16927, 2022. 1 +[50] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 586-595, 2018. 5, 6 +[51] Jiapeng Zhu, Yujun Shen, Deli Zhao, and Bolei Zhou. Indomain gan inversion for real image editing. In European Conference on Computer Vision, pages 592-608. Springer, 2020. 3 +[52] zllrunning. faceParsing.pytorch. https://github.com/zllrunning/faceParsing.PyTorch/, 2019.4.7 \ No newline at end of file diff --git a/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/images.zip b/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..991f43584e20d37e6092c322c6aaae66164daadf --- /dev/null +++ b/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:d36049c2385731e9d61843c5bb59cc6cec4a6a3bc629133f402282f0a7751ccd +size 821642 diff --git a/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/layout.json b/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..a8af463d37c7961eaf8affe33155c1a6e7620318 --- /dev/null +++ b/2023/Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding/layout.json @@ -0,0 +1,11474 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 69, + 122, + 507, + 157 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 122, + 507, + 157 + ], + "spans": [ + { + "bbox": [ + 69, + 122, + 507, + 157 + ], + "type": "text", + "content": "Make Encoder Great Again in 3D GAN Inversion through Geometry and Occlusion-Aware Encoding" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 117, + 178, + 471, + 192 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 117, + 178, + 471, + 192 + ], + "spans": [ + { + "bbox": [ + 117, + 178, + 471, + 192 + ], + "type": "text", + "content": "Ziyang Yuan" + }, + { + "bbox": [ + 117, + 178, + 471, + 192 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 117, + 178, + 471, + 192 + ], + "type": "text", + "content": " Yiming Zhu" + }, + { + "bbox": [ + 117, + 178, + 471, + 192 + ], + "type": "inline_equation", + "content": "^{1,2*}" + }, + { + "bbox": [ + 117, + 178, + 471, + 192 + ], + "type": "text", + "content": " Yu Li" + }, + { + "bbox": [ + 117, + 178, + 471, + 192 + ], + "type": "inline_equation", + "content": "^{2\\dagger}" + }, + { + "bbox": [ + 117, + 178, + 471, + 192 + ], + "type": "text", + "content": " Hongyu Liu" + }, + { + "bbox": [ + 117, + 178, + 471, + 192 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 117, + 178, + 471, + 192 + ], + "type": "text", + "content": " Chun Yuan" + }, + { + "bbox": [ + 117, + 178, + 471, + 192 + ], + "type": "inline_equation", + "content": "^{1\\dagger}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 52, + 192, + 541, + 219 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 192, + 541, + 219 + ], + "spans": [ + { + "bbox": [ + 52, + 192, + 541, + 219 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 52, + 192, + 541, + 219 + ], + "type": "text", + "content": "Tsinghua Shenzhen International Graduate School " + }, + { + "bbox": [ + 52, + 192, + 541, + 219 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 192, + 541, + 219 + ], + "type": "text", + "content": "International Digital Economy Academy (IDEA) " + }, + { + "bbox": [ + 52, + 192, + 541, + 219 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 52, + 192, + 541, + 219 + ], + "type": "text", + "content": "Hong Kong University of Science and Technology" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 224, + 221, + 368, + 231 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 224, + 221, + 368, + 231 + ], + "spans": [ + { + "bbox": [ + 224, + 221, + 368, + 231 + ], + "type": "text", + "content": "https://eg3d-goae.github.io" + } + ] + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 59, + 245, + 517, + 422 + ], + "blocks": [ + { + "bbox": [ + 59, + 245, + 517, + 422 + ], + "lines": [ + { + "bbox": [ + 59, + 245, + 517, + 422 + ], + "spans": [ + { + "bbox": [ + 59, + 245, + 517, + 422 + ], + "type": "image", + "image_path": "ff4e090a71aaba990dfbc75a0a5c1a02ec427b18c727a3c606c60c5cc096ee83.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 431, + 529, + 456 + ], + "lines": [ + { + "bbox": [ + 45, + 431, + 529, + 456 + ], + "spans": [ + { + "bbox": [ + 45, + 431, + 529, + 456 + ], + "type": "text", + "content": "Figure 1: The inversion and editing results of our method on human portraits and cat images. The novel view synthesized images demonstrate that our method can achieve high-quality inversion and editing given a single image input." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "bbox": [ + 139, + 465, + 185, + 476 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 139, + 465, + 185, + 476 + ], + "spans": [ + { + "bbox": [ + 139, + 465, + 185, + 476 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 45, + 481, + 279, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 481, + 279, + 714 + ], + "spans": [ + { + "bbox": [ + 45, + 481, + 279, + 714 + ], + "type": "text", + "content": "3D GAN inversion aims to achieve high reconstruction fidelity and reasonable 3D geometry simultaneously from a single image input. However, existing 3D GAN inversion methods rely on time-consuming optimization for each individual case. In this work, we introduce a novel encoder-based inversion framework based on EG3D, one of the most widely-used 3D GAN models. We leverage the inherent properties of EG3D's latent space to design a discriminator and a background depth regularization. This enables us to train a geometry-aware encoder capable of converting the input image into corresponding latent code. Additionally, we explore the feature space of EG3D and develop an adaptive refinement stage that improves the representation ability of features in EG3D to enhance the recovery of fine-grained textural details. Finally, we propose an occlusion-aware fusion operation to prevent distortion in unobserved regions. Our method achieves impressive results comparable to optimization-based methods while operating up to 500 times faster. Our framework is well-suited for applications such as semantic editing." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 298, + 465, + 375, + 476 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 465, + 375, + 476 + ], + "spans": [ + { + "bbox": [ + 298, + 465, + 375, + 476 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 296, + 484, + 530, + 636 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 484, + 530, + 636 + ], + "spans": [ + { + "bbox": [ + 296, + 484, + 530, + 636 + ], + "type": "text", + "content": "Recent advances in 3D-aware generative adversarial networks (GAN) (e.g. [5, 6, 14, 32]) have integrated neural radiance fields (NeRF) [27] into style-based generation, resulting in remarkable success in generating highly realistic 3D portraits. Similar to 2D GAN inversion techniques, 3D GAN inversion also projects images into the latent space of pre-trained 3D GAN models. However, in addition to pursuing faithful image reconstruction and preserving fined details, 3D GAN inversion also aims for accurate 3D geometry, which is critical for generating realistic and consistent multi-view images. This ability to ensure the correctness of 3D geometry is a crucial advantage of 3D GAN inversion over its 2D counterpart." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 636, + 531, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 636, + 531, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 636, + 531, + 730 + ], + "type": "text", + "content": "Some optimization-based methods, such as [21, 47, 49], first invert the image to a latent code to obtain a coarse 3D shape. They then synthesize pseudo-multi-view images with this shape using a warping process. These pseudo images are used as supervision to optimize the parameters of the 3D GAN for more precise 3D geometry and better detail preservation. While these iterative optimization-based pipelines can prevent shape collapse and produce accurate" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 77, + 42, + 119, + 71 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 77, + 42, + 119, + 71 + ], + "spans": [ + { + "bbox": [ + 77, + 42, + 119, + 71 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 151, + 41, + 470, + 73 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 151, + 41, + 470, + 73 + ], + "spans": [ + { + "bbox": [ + 151, + 41, + 470, + 73 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 60, + 719, + 208, + 730 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 719, + 208, + 730 + ], + "spans": [ + { + "bbox": [ + 60, + 719, + 208, + 730 + ], + "type": "text", + "content": "* Equal contributions; † Corresponding author." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "spans": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "text", + "content": "2437" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 45, + 106, + 279, + 141 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 106, + 279, + 141 + ], + "spans": [ + { + "bbox": [ + 45, + 106, + 279, + 141 + ], + "type": "text", + "content": "results, the optimization process needs to be performed for each individual case, which is time-consuming and impractical for many applications." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 45, + 143, + 279, + 353 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 143, + 279, + 353 + ], + "spans": [ + { + "bbox": [ + 45, + 143, + 279, + 353 + ], + "type": "text", + "content": "Several encoder-based methods [22, 23] leverage a pretrained 3D GAN to generate proxy data by randomly sampling latent codes and camera poses. They then employ these paired proxy data to train an encoder in a self-supervised fashion and further refine features in 3D GAN. These encoder-based techniques offer higher efficiency but lower high-fidelity reconstruction ability. Moreover, due to a domain gap between the paired proxy data and real images, the encoder may invert the in-the-wild images to unsuitable latent codes. To address this issue, we study the properties of the latent space in 3D GAN and develop a geometry-aware encoder that predicts the latent code incorporating these properties. Furthermore, since the latent code can not preserve details of input images well, we explore the characteristics of feature space in 3D GAN to help our method improve the performance in reconstructing the original appearance. The latent and feature spaces are widely discussed in 2D GAN inversion [11, 24, 42]." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 45, + 355, + 279, + 658 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 355, + 279, + 658 + ], + "spans": [ + { + "bbox": [ + 45, + 355, + 279, + 658 + ], + "type": "text", + "content": "This paper presents a novel encoder-based method for inverting 3D images generated by EG3D [5], a well-known and high-quality 3D GAN. Our approach is simple yet effective and is based on the discovery of a specific latent space within EG3D, which we call the canonical latent space " + }, + { + "bbox": [ + 45, + 355, + 279, + 658 + ], + "type": "inline_equation", + "content": "\\mathcal{W}_c" + }, + { + "bbox": [ + 45, + 355, + 279, + 658 + ], + "type": "text", + "content": ". We find that latent codes belonging to this space can produce human faces with superior 3D shape and texture quality following two principles. Firstly, the input pose before the mapping network of EG3D must be a static canonical pose throughout the generation process. Secondly, the depth of the background should fall within a fixed range. Based on this, we propose using an encoder to invert the image into this canonical latent space using a proposed latent code discriminator and depth regularization. Although our encoder produces a suitable latent code that preserves the reasonable 3D shape of the input image, but the code is low dimension, making it challenging to capture texture details. To address this, similar to the 2D GAN inversion [3, 45], we refine the selected features in EG3D based on the residual between the input image and reconstruction image with predicted latent code. Meanwhile, we also find there is a canonical feature space " + }, + { + "bbox": [ + 45, + 355, + 279, + 658 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_c" + }, + { + "bbox": [ + 45, + 355, + 279, + 658 + ], + "type": "text", + "content": " in EG3D, so we design an alignment module to project the refined feature to the canonical feature space. Moreover, we introduce an occlusion-aware fusion operation to avoid texture and shape distortions in reconstructing invisible regions." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 660, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 660, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 660, + 279, + 730 + ], + "type": "text", + "content": "We conduct comprehensive experiments to evaluate the efficiency and effectiveness of our method, and the results demonstrate that our method achieves high-quality inversion comparable to optimization-based methods and superior to other encoder-based methods. We also demonstrate our approach is effective in 3D-aware editing applications." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 296, + 106, + 531, + 142 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 106, + 531, + 142 + ], + "spans": [ + { + "bbox": [ + 296, + 106, + 531, + 142 + ], + "type": "text", + "content": "See Fig. 1 for some examples of inversion and editing of human portraits and cat faces obtained by our method. Our contribution can be summarised as following:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 308, + 148, + 530, + 341 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 308, + 148, + 530, + 182 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 148, + 530, + 182 + ], + "spans": [ + { + "bbox": [ + 308, + 148, + 530, + 182 + ], + "type": "text", + "content": "- We conduct an exploration on the latent space and feature space of EG3D and discover the presence of a canonical attribute." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 308, + 186, + 530, + 232 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 186, + 530, + 232 + ], + "spans": [ + { + "bbox": [ + 308, + 186, + 530, + 232 + ], + "type": "text", + "content": "- Based on our analysis of the characteristics of the canonical latent space, we propose a geometry-aware encoder by utilizing a canonical latent discriminator and depth regularization." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 308, + 234, + 530, + 281 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 234, + 530, + 281 + ], + "spans": [ + { + "bbox": [ + 308, + 234, + 530, + 281 + ], + "type": "text", + "content": "- We introduce an alignment module based on the canonical feature space and an occlusion-aware method to refine the selected features of the generator and supplement high-quality details." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 308, + 284, + 530, + 341 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 284, + 530, + 341 + ], + "spans": [ + { + "bbox": [ + 308, + 284, + 530, + 341 + ], + "type": "text", + "content": "- The proposed method exhibits competitive performance with existing methods in human portraits, both qualitatively and quantitatively. Additionally, our method can also generalize to the cat faces and is effective in 3D editing tasks." + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 297, + 352, + 381, + 364 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 352, + 381, + 364 + ], + "spans": [ + { + "bbox": [ + 297, + 352, + 381, + 364 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 297, + 372, + 496, + 384 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 372, + 496, + 384 + ], + "spans": [ + { + "bbox": [ + 297, + 372, + 496, + 384 + ], + "type": "text", + "content": "2.1. Generative 3D-Aware Image Synthesis." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 296, + 389, + 530, + 482 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 389, + 530, + 482 + ], + "spans": [ + { + "bbox": [ + 296, + 389, + 530, + 482 + ], + "type": "text", + "content": "Generative Adversarial Network [13] made significant advancements in generating both 2D photorealistic images [19, 20] and 3D-Aware consistent images. In 3D-aware image generation, some works build 3D GAN based on explicit 3D representations, such as point-cloud [41], voxel [28, 29, 43], and mesh [12, 15, 17]. However, these models often fail to generate high-resolution 3D scenes with high-quality details." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 483, + 530, + 668 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 483, + 530, + 668 + ], + "spans": [ + { + "bbox": [ + 296, + 483, + 530, + 668 + ], + "type": "text", + "content": "Since NeRF [27] achieved outstanding multi-view image synthesis, a sequence of works has begun to use implicit 3D representation and volume rendering for 3D generation [5, 6, 10, 14, 30, 32]. Pi-GAN [6] is the first attempt at using GAN to generate NeRF for 3D-aware image synthesis. After that, StyleNeRF [14] proposes a view-consistent upsampling module to generate high-resolution images. StyleSDF [32] combines an SDF-based volume renderer and a 2D CNN network to obtain geometry information. GRAM [10] introduces 2D manifolds to regulate point sampling strategy in volume rendering. EG3D [5] leverages StyleGAN2 [20]'s structure and designs a computationally efficient 3D representation called tri-plane. It can synthesize high-resolution view-consistent images and produces high-quality 3D geometry. We explore EG3D's latent space and build our inversion encoder based on EG3D." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 297, + 676, + 389, + 688 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 676, + 389, + 688 + ], + "spans": [ + { + "bbox": [ + 297, + 676, + 389, + 688 + ], + "type": "text", + "content": "2.2. GAN Inversion" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 296, + 694, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 694, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 694, + 530, + 730 + ], + "type": "text", + "content": "GAN Inversion is an inverse process of the generation that projects the given image to corresponding latent code for faithful reconstruction from the source image. Thus," + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "spans": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "text", + "content": "2438" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 52, + 103, + 273, + 181 + ], + "blocks": [ + { + "bbox": [ + 52, + 103, + 273, + 181 + ], + "lines": [ + { + "bbox": [ + 52, + 103, + 273, + 181 + ], + "spans": [ + { + "bbox": [ + 52, + 103, + 273, + 181 + ], + "type": "image", + "image_path": "dd8a273f71849cc80a28a40c177d163c1ab973c17154fd15b150f6595884c7f2.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 181, + 279, + 215 + ], + "lines": [ + { + "bbox": [ + 45, + 181, + 279, + 215 + ], + "spans": [ + { + "bbox": [ + 45, + 181, + 279, + 215 + ], + "type": "text", + "content": "Figure 2: Recap of EG3D. " + }, + { + "bbox": [ + 45, + 181, + 279, + 215 + ], + "type": "inline_equation", + "content": "z, p" + }, + { + "bbox": [ + 45, + 181, + 279, + 215 + ], + "type": "text", + "content": " denotes a Gaussian sample and a pose condition. The relation of " + }, + { + "bbox": [ + 45, + 181, + 279, + 215 + ], + "type": "inline_equation", + "content": "w, F" + }, + { + "bbox": [ + 45, + 181, + 279, + 215 + ], + "type": "text", + "content": ", and tri-plane is illustrated." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 45, + 239, + 279, + 378 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 239, + 279, + 378 + ], + "spans": [ + { + "bbox": [ + 45, + 239, + 279, + 378 + ], + "type": "text", + "content": "the image editing process can be conducted by semantic editing on the latent code [33, 37, 51]. In 2D GAN, inversion methods are mainly divided into three categories. Optimization-based methods [1, 8, 46] optimize the generator's latent code or parameters both, achieve high reconstruction quality, but are time-consuming. Encoder-based methods [2, 35, 42] train an encoder to project input images to the latent codes. These methods can get faster inference than optimization-based methods but unsatisfactory inversion fidelity. Hybrid methods [4, 36, 51] use an encoder to get a latent as initialization, then optimize the latent code and generator parameters, which is still time-consuming." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 380, + 280, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 380, + 280, + 602 + ], + "spans": [ + { + "bbox": [ + 45, + 380, + 280, + 602 + ], + "type": "text", + "content": "Unlike 2D methods, 3D GAN Inversion should also consider multi-view-consistence. Directly transferring 2D methods to the 3D inversion is prone to suffering geometry collapse and artifacts. To solve it, Pose Opt. [21] jointly optimizes camera pose, latent codes, and generator parameters. HFGI3D [47] is an optimization-based method that extracts mesh to create pseudo-multi-view supervision. Meanwhile, encoder methods are also gradually developing. IDE-3D [40] uses semantic segmentation to re-train EG3D and learns an encoder for inversion to edit images. NeRF-3DE [23] uses identity contrastive learning to train a based encoder and then trains a refining encoder for better details. E3DGE [22] trains a base encoder to learn coarse shape and texture and supplements local details with pixel-aligned features. However, existing encoder-based methods [22, 23] rely on synthetic paired data and may not generalize well to real-world scenarios. None of the state-of-the-art methods can handle time efficiency and 3D inversion quality simultaneously." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 45, + 615, + 154, + 628 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 615, + 154, + 628 + ], + "spans": [ + { + "bbox": [ + 45, + 615, + 154, + 628 + ], + "type": "text", + "content": "3. EG3D Exploration" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 635, + 279, + 671 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 635, + 279, + 671 + ], + "spans": [ + { + "bbox": [ + 45, + 635, + 279, + 671 + ], + "type": "text", + "content": "In this section, we first briefly review the EG3D model. Then, we explore and analyze the properties of latent space and feature space in EG3D." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "text", + "content": "The pipeline of EG3D is shown in Fig 2. It first combines a Gaussian vector " + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "text", + "content": " and a pose condition " + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "text", + "content": " as input and builds a mapper to generate a latent code " + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "text", + "content": ", this process can be denoted as " + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "inline_equation", + "content": "w = \\text{mapping}(z, p)" + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "text", + "content": ". Then this latent code " + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "text", + "content": " will be sent to each layer of a style-based hierarchical gen" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "spans": [ + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "text", + "content": "erator to obtain the feature maps " + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "text", + "content": ". These feature maps are enlarged layer by layer. The last layer's feature map reshape to tri-plane, an efficient 3D representation consists of three axis-aligned feature planes " + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "inline_equation", + "content": "(F_{xy}, F_{xz}, F_{yz})" + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "text", + "content": ". With this efficient 3D representation, EG3D samples point features from the tri-plane to synthesize multi-view images or depths by a rendering decoder " + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "inline_equation", + "content": "R_{dec}" + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "text", + "content": " with volume rendering [27]. Similar to the 2D GAN, the latent code " + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "text", + "content": " belongs to a latent space " + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "inline_equation", + "content": "\\mathcal{W}" + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "text", + "content": ", and all feature maps in the generator construct the " + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 296, + 106, + 530, + 223 + ], + "type": "text", + "content": " space." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 296, + 234, + 443, + 247 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 234, + 443, + 247 + ], + "spans": [ + { + "bbox": [ + 296, + 234, + 443, + 247 + ], + "type": "text", + "content": "3.1. Canonical Latent Space " + }, + { + "bbox": [ + 296, + 234, + 443, + 247 + ], + "type": "inline_equation", + "content": "\\mathcal{W}_c" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "spans": [ + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "type": "text", + "content": "In order to investigate the properties of the latent space " + }, + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "type": "inline_equation", + "content": "\\mathcal{W}" + }, + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "type": "text", + "content": " and its relationship with pose conditioning, we adopt a fixed " + }, + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "type": "text", + "content": " and sample various pose conditions to generate corresponding latent code " + }, + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "type": "text", + "content": ". Fig. 3 illustrates that when " + }, + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "type": "text", + "content": " is conditioned on an unsuitable pose " + }, + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 296, + 254, + 530, + 427 + ], + "type": "text", + "content": " far away from the canonical pose, the generated 3D shapes fail to generalize to other views synthesis. Only when the pose condition is canonical can the synthesized images maintain shape and texture consistency across multiple views. Meanwhile, we find a clear depth gap between the face and background regions when generating good results with the canonical pose condition. Under canonical pose, the depth of the background is restricted to a fixed range, while the face and background regions are confused for the other pose conditions." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 430, + 531, + 570 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 430, + 531, + 570 + ], + "spans": [ + { + "bbox": [ + 296, + 430, + 531, + 570 + ], + "type": "text", + "content": "These observations lead us to identify a specific subspace of " + }, + { + "bbox": [ + 296, + 430, + 531, + 570 + ], + "type": "inline_equation", + "content": "\\mathcal{W}" + }, + { + "bbox": [ + 296, + 430, + 531, + 570 + ], + "type": "text", + "content": " intuitively, which we call canonical latent space, denoted as " + }, + { + "bbox": [ + 296, + 430, + 531, + 570 + ], + "type": "inline_equation", + "content": "\\mathcal{W}_c" + }, + { + "bbox": [ + 296, + 430, + 531, + 570 + ], + "type": "text", + "content": ", that is responsible for ensuring reasonable 3D shape and texture across multiple views. There are two principles of this canonical latent space. Firstly, the input pose before the mapping network of EG3D must be a static canonical pose. Secondly, the depth of the background should fall within a fixed range to distinguish the face and background regions. Based on these findings, we propose that a high-quality 3D-GAN inversion method should first retrieve a " + }, + { + "bbox": [ + 296, + 430, + 531, + 570 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 296, + 430, + 531, + 570 + ], + "type": "text", + "content": " latent code in " + }, + { + "bbox": [ + 296, + 430, + 531, + 570 + ], + "type": "inline_equation", + "content": "\\mathcal{W}_c" + }, + { + "bbox": [ + 296, + 430, + 531, + 570 + ], + "type": "text", + "content": " to ensure the best possible image synthesis results." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 581, + 446, + 595 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 581, + 446, + 595 + ], + "spans": [ + { + "bbox": [ + 296, + 581, + 446, + 595 + ], + "type": "text", + "content": "3.2. Canonical Feature Space " + }, + { + "bbox": [ + 296, + 581, + 446, + 595 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_c" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "text", + "content": "To analyze the characteristics of " + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "text", + "content": " space, we generate the latent codes with different pose conditions to synthesize multiple tri-planes. We visualize the tri-plane as illustrated in Fig 3. The tri-plane also represents a canonical view when the pose condition is canonical (i.e., the columns " + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "inline_equation", + "content": "\\mathrm{g} \\sim \\mathrm{i}" + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "text", + "content": " in row " + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "inline_equation", + "content": "\\mathrm{L}_2" + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "text", + "content": "). It indicates that there is also a specific subspace of " + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "text", + "content": ", we call it canonical feature space, denoted as " + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_c" + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "text", + "content": ", and the canonical latent space " + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "inline_equation", + "content": "\\mathcal{W}_c" + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "text", + "content": " produces the canonical feature space " + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_c" + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "text", + "content": " with the generator layers. The " + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_c" + }, + { + "bbox": [ + 296, + 601, + 530, + 730 + ], + "type": "text", + "content": " can supply sufficient facial information for rendering multi-view images." + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "spans": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "text", + "content": "2439" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 47, + 90, + 215, + 277 + ], + "blocks": [ + { + "bbox": [ + 47, + 90, + 215, + 277 + ], + "lines": [ + { + "bbox": [ + 47, + 90, + 215, + 277 + ], + "spans": [ + { + "bbox": [ + 47, + 90, + 215, + 277 + ], + "type": "image", + "image_path": "de5cd014efd237fc56102bee1b6e8ef4ca24f9fb81acddfdcfe8d6b23a5a3ee9.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "lines": [ + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "spans": [ + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "text", + "content": "Figure 3: Illustration of canonical Pose condition. We synthesize multi-view images for three pose conditions " + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "text", + "content": ", including left, right, and canonical. As shown in a " + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "inline_equation", + "content": "\\sim" + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "text", + "content": "c, the canonical pose condition in row " + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "inline_equation", + "content": "L_2" + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "text", + "content": " has no distortion face shape. Moreover, depth maps in row " + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "inline_equation", + "content": "L_2" + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "text", + "content": " demonstrate that images on the canonical pose condition have significant foreground and background differences. In contrast, flattened shape depth maps in rows " + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "inline_equation", + "content": "L_1" + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "inline_equation", + "content": "L_3" + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "text", + "content": " have foreground and background confusion. Columns " + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "inline_equation", + "content": "g \\sim i" + }, + { + "bbox": [ + 45, + 280, + 531, + 340 + ], + "type": "text", + "content": " reveal the tri-plane is also related to the pose condition." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 219, + 90, + 367, + 277 + ], + "blocks": [ + { + "bbox": [ + 219, + 90, + 367, + 277 + ], + "lines": [ + { + "bbox": [ + 219, + 90, + 367, + 277 + ], + "spans": [ + { + "bbox": [ + 219, + 90, + 367, + 277 + ], + "type": "image", + "image_path": "2a8c83275cf93259cce48a9c9c7a81e64fc91c8b5a1253cf572403cd3a7983d2.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 370, + 90, + 529, + 273 + ], + "blocks": [ + { + "bbox": [ + 370, + 90, + 529, + 273 + ], + "lines": [ + { + "bbox": [ + 370, + 90, + 529, + 273 + ], + "spans": [ + { + "bbox": [ + 370, + 90, + 529, + 273 + ], + "type": "image", + "image_path": "dbccfbbc7ec4150e734c740ab84ba1015919e167031e77aa31ecd59b4d154d8c.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 350, + 100, + 362 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 350, + 100, + 362 + ], + "spans": [ + { + "bbox": [ + 45, + 350, + 100, + 362 + ], + "type": "text", + "content": "4. Method" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "spans": [ + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "text", + "content": "The pipeline of our method is shown in Fig. 4. We first project the input image " + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "text", + "content": " to the latent code " + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "inline_equation", + "content": "w^{+} \\subset \\mathbb{R}^{14 \\times 512}" + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "text", + "content": " with our encoder, where " + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "inline_equation", + "content": "w^{+} = (w_{0}, w_{1}, \\dots, w_{13})" + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "text", + "content": " is an extension of latent code " + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "text", + "content": " and can preserve the details better as mentioned in 2D GAN inversion [35, 42]. Then we calculate the residual between " + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "text", + "content": " and the generated image " + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "inline_equation", + "content": "I_{w^{+}}" + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "text", + "content": " based on " + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "text", + "content": " to refine the features of the generator. In the following Sec. 4.1 and Sec. 4.2, we will describe how we ensure the latent code " + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 369, + 282, + 532 + ], + "type": "text", + "content": " and refined feature belong to the canonical space, respectively. Furthermore, we introduce an occlusion-aware mix tri-plane in Sec. 4.3 to avoid the distortion of invisible regions reconstruction. In Sec. 4.4, we exhibit how to perform 3D semantic editing with our inversion method." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 540, + 186, + 553 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 540, + 186, + 553 + ], + "spans": [ + { + "bbox": [ + 45, + 540, + 186, + 553 + ], + "type": "text", + "content": "4.1. Geometry-aware Encoder" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "spans": [ + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "text", + "content": "We design a geometry-aware encoder to obtain the latent code " + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "text", + "content": " given the input image " + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "text", + "content": " and corresponding rendering camera pose " + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "inline_equation", + "content": "c" + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "text", + "content": ". We generate the inverted latent code " + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "text", + "content": " according to the backbone's pyramid feature progressively. It is worth noting that we choose Swin-transformer [25] as the backbone and further add attention modules at different scale feature layers for different level latent codes (more details of encoder architecture are in supplementary materials). After projecting the input image to the latent code " + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "text", + "content": ", we can synthesize the tri-plane " + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "text", + "content": " through EG3D generator " + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "inline_equation", + "content": "G" + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "text", + "content": " and use rendering decoder " + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "inline_equation", + "content": "R_{dec}" + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "text", + "content": " to get the reconstruction image " + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "inline_equation", + "content": "I_{w^{+}}" + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "text", + "content": " under the rendering camera pose " + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "inline_equation", + "content": "c" + }, + { + "bbox": [ + 45, + 558, + 279, + 698 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 122, + 707, + 279, + 724 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 122, + 707, + 279, + 724 + ], + "spans": [ + { + "bbox": [ + 122, + 707, + 279, + 724 + ], + "type": "interline_equation", + "content": "w ^ {+} = E (I), \\tag {1}", + "image_path": "0d924f13f468561266bd7754ba1b3e844bdf08583bf3df5c8969f624c1bd9388.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 121, + 721, + 204, + 732 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 121, + 721, + 204, + 732 + ], + "spans": [ + { + "bbox": [ + 121, + 721, + 204, + 732 + ], + "type": "interline_equation", + "content": "I _ {w ^ {+}} = R _ {d e c} (G (w ^ {+}), c)", + "image_path": "f40a619a9b9efda8645f12133a20a51dace36c0059873ad99e8fb40cc75ff529.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "spans": [ + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "text", + "content": "To make the inverted " + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "text", + "content": " not deviate far from the canonical space " + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "inline_equation", + "content": "\\mathcal{W}_c" + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "text", + "content": " discussed in Sec. 3.1, we use a canonical latent discriminator [31] to discriminate between " + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "inline_equation", + "content": "w_{c} \\in \\mathcal{W}_{c}" + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "text", + "content": ". The canonical latent discriminator, denoted as " + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{\\mathcal{W}_c}" + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "text", + "content": ", is trained in an adversarial scheme with the non-saturating GAN loss [13] and " + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "inline_equation", + "content": "R_{1}" + }, + { + "bbox": [ + 297, + 351, + 531, + 433 + ], + "type": "text", + "content": " regularization [26], the loss of adversarial learning process can be written as below:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 442, + 530, + 508 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 442, + 530, + 508 + ], + "spans": [ + { + "bbox": [ + 304, + 442, + 530, + 508 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {L} _ {\\mathrm {a d v}} ^ {\\mathcal {D} \\mathcal {W} _ {c}} = - \\mathbb {E} [ \\log \\mathcal {D} _ {\\mathcal {W} _ {c}} (w _ {c}) ] - \\mathbb {E} [ \\log (1 - \\mathcal {D} _ {\\mathcal {W} _ {c}} (w _ {i})) ] (2) \\\\ + \\frac {\\gamma}{2} \\mathbb {E} \\left[ \\| \\nabla \\mathcal {D} _ {\\mathcal {W} _ {c}} \\left(w _ {c}\\right) \\| _ {2} \\right], \\\\ \\mathcal {L} _ {\\mathrm {a d v}} ^ {E} = - \\mathbb {E} \\left[ \\log \\mathcal {D} _ {\\mathcal {W} _ {c}} \\left(w _ {i}\\right) \\right], (3) \\\\ \\end{array}", + "image_path": "fa27192a29a8639d0868c822d8f1f955a73919a115fb8f2932a1ae0b6f663207.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "spans": [ + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "text", + "content": " is the weight of " + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "inline_equation", + "content": "R_{1}" + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "text", + "content": " regularization, the " + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{adv}}^{\\mathcal{D}_{\\mathcal{W}_c}}" + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{adv}}^{E}" + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "text", + "content": " are the loss for the latent discriminator " + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{\\mathcal{W}_c}" + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "text", + "content": " and encoder respectively. " + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{\\mathcal{W}_c}" + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "text", + "content": " operates on " + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "inline_equation", + "content": "w_{c}" + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "text", + "content": " and each entry " + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "inline_equation", + "content": "w_{i}" + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "text", + "content": " of " + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 297, + 515, + 530, + 562 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 564, + 530, + 703 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 564, + 530, + 703 + ], + "spans": [ + { + "bbox": [ + 296, + 564, + 530, + 703 + ], + "type": "text", + "content": "As discussed in Sec. 3.1, the background depth of an integrated face should be limited in a range. To estimate the background depth, we first random sample 0.1 million front images with the canonical pose condition, then we obtain the depth maps and background regions of these images. We use the parsing method [52] to get a binary mask " + }, + { + "bbox": [ + 296, + 564, + 530, + 703 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 296, + 564, + 530, + 703 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 296, + 564, + 530, + 703 + ], + "type": "inline_equation", + "content": "M = 1" + }, + { + "bbox": [ + 296, + 564, + 530, + 703 + ], + "type": "text", + "content": " indicates the background region and 0 otherwise. Finally, we calculate the average depth " + }, + { + "bbox": [ + 296, + 564, + 530, + 703 + ], + "type": "inline_equation", + "content": "D_{avg}" + }, + { + "bbox": [ + 296, + 564, + 530, + 703 + ], + "type": "text", + "content": " of background regions of these samples, and we set the " + }, + { + "bbox": [ + 296, + 564, + 530, + 703 + ], + "type": "inline_equation", + "content": "D_{avg}" + }, + { + "bbox": [ + 296, + 564, + 530, + 703 + ], + "type": "text", + "content": " as a regularization to constrain the background depth during inversion, the background regularization can be written as below:" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 344, + 717, + 530, + 730 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 344, + 717, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 344, + 717, + 530, + 730 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {B G} = \\left\\| D \\odot M - D _ {\\text {a v g}} \\odot M \\right\\| _ {2}. \\tag {4}", + "image_path": "855c33c6db8c9d91e9ea5d3ed715b76214453800f8b689097105d6c75dd5b4c6.jpg" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "spans": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "text", + "content": "2440" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 86, + 91, + 494, + 248 + ], + "blocks": [ + { + "bbox": [ + 86, + 91, + 494, + 248 + ], + "lines": [ + { + "bbox": [ + 86, + 91, + 494, + 248 + ], + "spans": [ + { + "bbox": [ + 86, + 91, + 494, + 248 + ], + "type": "image", + "image_path": "27ea64ea00de07ed3c1a11bf130ff831174d290515212f0bdfb90d8307e367ab.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "lines": [ + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "spans": [ + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": "Figure 4: Overview of our method. Our framework could be divided into two parts. (1) " + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "\\mathcal{W}" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": " space inversion. We design an encoder " + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "E" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": " to invert input image " + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": " into " + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": " latent codes. The " + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": " latent codes are fed into a pre-trained EG3D generator " + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "G" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": " to get tri-plane" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "_{w^{+}}" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": " and rendered into reconstruction image " + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "I_{w^{+}}" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": ". (2) Complement the " + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": " space. We calculate the image residual " + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "\\Delta I" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": " between the input image and its reconstruction and propose AFA module to refine the F latent maps. The modified latent maps " + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "F^{*}" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": " are transformed into tri-plane" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "_{mix}" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": " by occlusion-aware mix and rendered into the fine detailed inversion image " + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "inline_equation", + "content": "I_{F^{*}}" + }, + { + "bbox": [ + 45, + 249, + 530, + 308 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 45, + 316, + 279, + 339 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 316, + 279, + 339 + ], + "spans": [ + { + "bbox": [ + 45, + 316, + 279, + 339 + ], + "type": "text", + "content": "Here, " + }, + { + "bbox": [ + 45, + 316, + 279, + 339 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 45, + 316, + 279, + 339 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 45, + 316, + 279, + 339 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 45, + 316, + 279, + 339 + ], + "type": "text", + "content": " are the depth map and background mask inverted image under the front-view pose." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "spans": [ + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "type": "text", + "content": "In addition, we use reconstruction loss function " + }, + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{rec}" + }, + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "type": "text", + "content": " follow pSp [35] in the training stage. The " + }, + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{rec}" + }, + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "type": "text", + "content": " is composed by pixel-wise " + }, + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_2" + }, + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "type": "text", + "content": " loss, perceptual loss " + }, + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{LPIPS}" + }, + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "type": "text", + "content": " [50], and facial identity similarity loss " + }, + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{ID}" + }, + { + "bbox": [ + 45, + 340, + 279, + 398 + ], + "type": "text", + "content": " with pre-trained ArcFace network [9]:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 52, + 404, + 279, + 416 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 404, + 279, + 416 + ], + "spans": [ + { + "bbox": [ + 52, + 404, + 279, + 416 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {r e c} = \\left\\| I _ {w ^ {+}} - I \\right\\| _ {2} + \\mathcal {L} _ {L P I P S} \\left(I _ {w ^ {+}}, I\\right) + \\mathcal {L} _ {I D} \\left(I _ {w ^ {+}}, I\\right). \\tag {5}", + "image_path": "eefdb2b1de9aa73b0e247683486e999b1a4b9b3d19ab3e3d05e24c76c29121a0.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 421, + 198, + 433 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 421, + 198, + 433 + ], + "spans": [ + { + "bbox": [ + 45, + 421, + 198, + 433 + ], + "type": "text", + "content": "4.2. Adaptive Feature Alignment" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "spans": [ + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "type": "text", + "content": "It is non-trivial to restore fine-detailed texture with only a highly compressed " + }, + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "type": "text", + "content": " latent code. Thus, adjusting high-dimension feature maps in the " + }, + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "type": "text", + "content": " space is natural to achieve high-fidelity inversion as mentioned in related 2D GAN inversion methods [3, 11, 45]. Moreover, it is worth noting that the feature maps " + }, + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "type": "text", + "content": " generated with our inverted " + }, + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "type": "text", + "content": " are in the canonical feature space " + }, + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_c" + }, + { + "bbox": [ + 45, + 438, + 279, + 520 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "spans": [ + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "text", + "content": "We calculate the residual " + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "inline_equation", + "content": "\\Delta I" + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "text", + "content": " between " + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "inline_equation", + "content": "I_{w^{+}}" + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "text", + "content": " and hope to refine the feature maps to eliminate this residual. However, directly setting the residual as input and predicting the refined feature maps with a CNN to modify " + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "text", + "content": " is invalid. This is because the residual is highly entangled with the view of the input image, while " + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "text", + "content": " is in " + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_c" + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "text", + "content": ". When the view is not canonical, the refined feature maps with this residual can not project to the " + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_c" + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "text", + "content": " space simply. Thus, aligning the residual feature maps to the " + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_c" + }, + { + "bbox": [ + 45, + 520, + 279, + 636 + ], + "type": "text", + "content": " space is necessary to synthesize high-quality images, as mentioned in Sec. 3.2." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "content": "According to the above analysis, we propose an adaptive feature alignment (AFA) module that enables automatic canonical space alignment by cross-attention mechanism, as shown in Fig 5. First, we use a CNN to capture the feature " + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "inline_equation", + "content": "F_{\\Delta I}" + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "content": " of " + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "inline_equation", + "content": "\\Delta I" + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "content": ", and we take " + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "inline_equation", + "content": "F_{\\Delta I}" + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "content": " as the key " + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "content": ", value " + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "inline_equation", + "content": "V" + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "content": ", and the feature map " + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "content": " as a query " + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "content": ". Then, we utilize cross-attention modules to align the " + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "inline_equation", + "content": "F_{\\Delta I}" + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "content": " and output a feature " + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "inline_equation", + "content": "F_{\\text{align}}" + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "content": ". Since the " + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 45, + 637, + 279, + 730 + ], + "type": "text", + "content": " is already in the canonical feature" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 299, + 316, + 529, + 386 + ], + "blocks": [ + { + "bbox": [ + 299, + 316, + 529, + 386 + ], + "lines": [ + { + "bbox": [ + 299, + 316, + 529, + 386 + ], + "spans": [ + { + "bbox": [ + 299, + 316, + 529, + 386 + ], + "type": "image", + "image_path": "2dbb1e67ed2d33a6228061091285998fc37361098f40d10f876460efa53932b4.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "lines": [ + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "spans": [ + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "text", + "content": "Figure 5: The Architecture of AFA Module. We use a CNN to capture the feature " + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "inline_equation", + "content": "F_{\\Delta I}" + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "text", + "content": " of residual image " + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "inline_equation", + "content": "\\Delta I" + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "text", + "content": ", and align the " + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "inline_equation", + "content": "F_{\\Delta I}" + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "text", + "content": " with cross attention module. Finally, we refine the " + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "text", + "content": " with the aligned feature " + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "inline_equation", + "content": "F_{\\text{align}}" + }, + { + "bbox": [ + 296, + 388, + 530, + 436 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "spans": [ + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "text", + "content": "space " + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_c" + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "text", + "content": ", and the feature " + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "inline_equation", + "content": "F_{align}" + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "text", + "content": " can also have the properties of " + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_c" + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "text", + "content": " space. Finally, we use the " + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "inline_equation", + "content": "F_{align}" + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "text", + "content": " to predict the scale map " + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "text", + "content": " and translation map " + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "text", + "content": " to refine the " + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 296, + 444, + 530, + 501 + ], + "type": "text", + "content": " with Feature-wise Linear Modulation (FiLM) [34]. The whole process of our AFA module can be formulated as follows:" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 333, + 508, + 416, + 522 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 333, + 508, + 416, + 522 + ], + "spans": [ + { + "bbox": [ + 333, + 508, + 416, + 522 + ], + "type": "interline_equation", + "content": "F _ {\\Delta I} = C N N (\\Delta I),", + "image_path": "ce72b8692007c3ee3d072a4ccd3cfc620a86dfd00304af6162eea9489414c5d5.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 333, + 523, + 483, + 536 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 333, + 523, + 483, + 536 + ], + "spans": [ + { + "bbox": [ + 333, + 523, + 483, + 536 + ], + "type": "interline_equation", + "content": "Q, K, V = W _ {Q} F, W _ {K} F _ {\\Delta I}, W _ {V} F _ {\\Delta I},", + "image_path": "2f375a6085c052a9bba814f46a579fc37b35025ecc11a16f14b9eded61ea0011.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 333, + 538, + 530, + 551 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 333, + 538, + 530, + 551 + ], + "spans": [ + { + "bbox": [ + 333, + 538, + 530, + 551 + ], + "type": "interline_equation", + "content": "F _ {\\text {a l i g n}} = \\text {A t t e n t i o n} (Q, K, V), \\tag {6}", + "image_path": "268f045c43ba7003957c34fc27976d46542e56504b8655d5864683f4c2984d68.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 333, + 552, + 493, + 565 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 333, + 552, + 493, + 565 + ], + "spans": [ + { + "bbox": [ + 333, + 552, + 493, + 565 + ], + "type": "interline_equation", + "content": "\\gamma , \\beta = C o n v _ {\\gamma} (F _ {a l i g n}), C o n v _ {\\beta} (F _ {a l i g n}),", + "image_path": "ffa26ef2573f76f6a35a30a649ee377557826fac934ab3c6510d33bfe07d702c.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 334, + 567, + 408, + 580 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 334, + 567, + 408, + 580 + ], + "spans": [ + { + "bbox": [ + 334, + 567, + 408, + 580 + ], + "type": "interline_equation", + "content": "F ^ {*} = \\gamma \\odot F + \\beta ,", + "image_path": "4b6e7a2fc73e7609736c4d79ae74f8f171cd1ce26ea5162e8370505f5ba158b1.jpg" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "spans": [ + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "inline_equation", + "content": "W_{Q}, W_{K}, W_{V}" + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "text", + "content": " are learnable projection heads and " + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "text", + "content": " is the dimension of feature, the " + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "inline_equation", + "content": "F^{*}" + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "text", + "content": " is the final output of our AFA module. With this adaptive alignment, we achieve a detailed complement of " + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "inline_equation", + "content": "\\mathcal{F}_c" + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "text", + "content": " space. Note that we adopt " + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{total}" + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "text", + "content": " and a " + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_2" + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "text", + "content": " regularization loss on " + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "inline_equation", + "content": "\\Delta F = F^{*} - F" + }, + { + "bbox": [ + 296, + 588, + 530, + 657 + ], + "type": "text", + "content": " when training the AFA module." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 296, + 665, + 461, + 677 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 665, + 461, + 677 + ], + "spans": [ + { + "bbox": [ + 296, + 665, + 461, + 677 + ], + "type": "text", + "content": "4.3. Occlusion-aware Mix Tri-plane" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 296, + 682, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 682, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 682, + 530, + 730 + ], + "type": "text", + "content": "The image residual " + }, + { + "bbox": [ + 296, + 682, + 530, + 730 + ], + "type": "inline_equation", + "content": "\\Delta I" + }, + { + "bbox": [ + 296, + 682, + 530, + 730 + ], + "type": "text", + "content": " only contains information in the visible area of the input view. Using single-view residuals to modify the entire " + }, + { + "bbox": [ + 296, + 682, + 530, + 730 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 296, + 682, + 530, + 730 + ], + "type": "text", + "content": " will lead to distortion at the occlusion region. To solve this problem, we propose the Occlusion-" + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "spans": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "text", + "content": "2441" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 45, + 106, + 130, + 117 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 106, + 130, + 117 + ], + "spans": [ + { + "bbox": [ + 45, + 106, + 130, + 117 + ], + "type": "text", + "content": "aware Mix Tri-plane." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 45, + 117, + 279, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 117, + 279, + 193 + ], + "spans": [ + { + "bbox": [ + 45, + 117, + 279, + 193 + ], + "type": "text", + "content": "The tri-plane contains all points in the 3D space which are divided into visible points set and occlusion points set according to the input view. Here, we define the 3D points viewed in the input image in tri-plane as the visible points set " + }, + { + "bbox": [ + 45, + 117, + 279, + 193 + ], + "type": "inline_equation", + "content": "\\mathcal{V}_{(x,y,z)}" + }, + { + "bbox": [ + 45, + 117, + 279, + 193 + ], + "type": "text", + "content": ", points in the occlusion regions as occlusion points set " + }, + { + "bbox": [ + 45, + 117, + 279, + 193 + ], + "type": "inline_equation", + "content": "\\mathcal{O}_{(x,y,z)}" + }, + { + "bbox": [ + 45, + 117, + 279, + 193 + ], + "type": "text", + "content": ". We can get the depth map " + }, + { + "bbox": [ + 45, + 117, + 279, + 193 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 45, + 117, + 279, + 193 + ], + "type": "text", + "content": " under the input view, and the two points set can be defined by:" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 52, + 201, + 279, + 237 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 201, + 279, + 237 + ], + "spans": [ + { + "bbox": [ + 52, + 201, + 279, + 237 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {V} _ {(x, y, z)} = \\left\\{\\left[ x, y, z \\right] ^ {T}: \\left[ x, y, z \\right] ^ {T} = \\pi D (u, v) \\mathcal {K} ^ {- 1} \\left[ u, v, 1 \\right] ^ {T} \\right\\}, \\\\ \\mathcal {O} _ {(x, y, z)} = \\mathbb {R} ^ {3} \\backslash \\mathcal {V} _ {(x, y, z)}, \\tag {7} \\\\ \\end{array}", + "image_path": "7a4cf4bb67b5bf6815e757303abf3885c860c2eda104603b2c380145d9cc0b19.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "spans": [ + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "type": "inline_equation", + "content": "[u,v,1]" + }, + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "type": "text", + "content": " is the pixel homogeneous coordinate of the input image, " + }, + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "type": "inline_equation", + "content": "\\pi" + }, + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "type": "text", + "content": " is the extrinsic camera parameter matrix of the input view, " + }, + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "type": "inline_equation", + "content": "D(u,v)" + }, + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "type": "text", + "content": " is the depth of pixel " + }, + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "type": "inline_equation", + "content": "[u,v]" + }, + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "type": "inline_equation", + "content": "\\mathcal{K}" + }, + { + "bbox": [ + 45, + 239, + 279, + 284 + ], + "type": "text", + "content": " is the intrinsic camera parameter matrix." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 45, + 286, + 279, + 319 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 286, + 279, + 319 + ], + "spans": [ + { + "bbox": [ + 45, + 286, + 279, + 319 + ], + "type": "text", + "content": "After determining the visible area, we can supplement the refined details of the input view to the tri-plane. We define the occlusion-aware mix tri-plane as follows:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 85, + 329, + 279, + 387 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 85, + 329, + 279, + 387 + ], + "spans": [ + { + "bbox": [ + 85, + 329, + 279, + 387 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\operatorname {t r i - p l a n e} _ {w ^ {+}} = G \\left(w ^ {+}\\right), \\\\ \\operatorname {t r i - p l a n e} _ {F ^ {*}} = G \\left(F ^ {*}\\right), (8) \\\\ \\left. \\operatorname {t r i - p l a n e} _ {\\text {m i x}} = \\operatorname {t r i - p l a n e} _ {F ^ {*}} \\right| _ {(x, y, z) \\in \\mathcal {V}} (6) \\\\ + \\operatorname {t r i - p l a n e} _ {w +} | _ {(x, y, z) \\in \\mathcal {O}}, \\\\ \\end{array}", + "image_path": "65092fe5ea09786b0cc94a65b55c7c07ee4956d55b226db4b639b0538ad52f84.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 396, + 279, + 442 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 396, + 279, + 442 + ], + "spans": [ + { + "bbox": [ + 45, + 396, + 279, + 442 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 45, + 396, + 279, + 442 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 396, + 279, + 442 + ], + "type": "text", + "content": " is the latent code learned from the encoder, and " + }, + { + "bbox": [ + 45, + 396, + 279, + 442 + ], + "type": "inline_equation", + "content": "F^{*}" + }, + { + "bbox": [ + 45, + 396, + 279, + 442 + ], + "type": "text", + "content": " is the refined feature map. Finally, we use tri-planes mix with rendering decoder to synthesize images under different views when inference." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 45, + 452, + 102, + 463 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 452, + 102, + 463 + ], + "spans": [ + { + "bbox": [ + 45, + 452, + 102, + 463 + ], + "type": "text", + "content": "4.4. Editing" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "spans": [ + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "text", + "content": "To achieve 3D-consistent editing, we need to modify both " + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "inline_equation", + "content": "F^{*}" + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "text", + "content": ". We first get the edited latent code " + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "inline_equation", + "content": "\\hat{w}^{+}" + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "text", + "content": " through classic latent code editing methods [33, 37]. Then for " + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "inline_equation", + "content": "F^{*}" + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "text", + "content": ", we follow FS [48] to extract the features " + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "inline_equation", + "content": "F^{\\hat{w}^{+}}" + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "inline_equation", + "content": "F^{w}" + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "text", + "content": " from the generator convolution layer with input " + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "inline_equation", + "content": "\\hat{w}^{+}" + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "text", + "content": ", respectively. Finally, we calculate the difference between these two features and add it to the " + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "inline_equation", + "content": "F^{*}" + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "text", + "content": " to get the edited features " + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "inline_equation", + "content": "\\hat{F^{*}}" + }, + { + "bbox": [ + 45, + 469, + 279, + 563 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 113, + 573, + 279, + 586 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 113, + 573, + 279, + 586 + ], + "spans": [ + { + "bbox": [ + 113, + 573, + 279, + 586 + ], + "type": "interline_equation", + "content": "\\hat {F} ^ {*} = F ^ {*} + F ^ {\\hat {w} ^ {+}} - F ^ {w}. \\tag {9}", + "image_path": "fe33786bf2de5042a561a1d43871634b25e6fc02af07a1c117e21d6cfd70e874.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 45, + 598, + 279, + 634 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 598, + 279, + 634 + ], + "spans": [ + { + "bbox": [ + 45, + 598, + 279, + 634 + ], + "type": "text", + "content": "With the modified " + }, + { + "bbox": [ + 45, + 598, + 279, + 634 + ], + "type": "inline_equation", + "content": "\\hat{w}^{+}" + }, + { + "bbox": [ + 45, + 598, + 279, + 634 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 45, + 598, + 279, + 634 + ], + "type": "inline_equation", + "content": "\\hat{F}^{*}" + }, + { + "bbox": [ + 45, + 598, + 279, + 634 + ], + "type": "text", + "content": ", we use the method in section 4.3 to get edited mix tri-plane, and use rendering decoder to synthesize 3D-consistent edited images." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 45, + 642, + 99, + 654 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 642, + 99, + 654 + ], + "spans": [ + { + "bbox": [ + 45, + 642, + 99, + 654 + ], + "type": "text", + "content": "4.5. Losses." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 45, + 660, + 279, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 660, + 279, + 696 + ], + "spans": [ + { + "bbox": [ + 45, + 660, + 279, + 696 + ], + "type": "text", + "content": "In the first training stage, we use the loss function mentioned in Sec 4.1. For the input view reconstruction, the loss " + }, + { + "bbox": [ + 45, + 660, + 279, + 696 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{rec}" + }, + { + "bbox": [ + 45, + 660, + 279, + 696 + ], + "type": "text", + "content": " is computed by:" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 706, + 278, + 730 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 706, + 278, + 730 + ], + "spans": [ + { + "bbox": [ + 46, + 706, + 278, + 730 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {r e c} = \\lambda_ {1} \\| I _ {w ^ {+}} - I \\| _ {2} + \\lambda_ {2} \\mathcal {L} _ {L P I P S} \\left(I _ {w ^ {+}}, I\\right) + \\lambda_ {3} \\mathcal {L} _ {I D} \\left(I _ {w ^ {+}}, I\\right), \\tag {10}", + "image_path": "c414284497f586551e10eca6612f90bcae1cbe0d1a5395703dac1cc4b0fc9416.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 296, + 106, + 530, + 140 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 106, + 530, + 140 + ], + "spans": [ + { + "bbox": [ + 296, + 106, + 530, + 140 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 296, + 106, + 530, + 140 + ], + "type": "inline_equation", + "content": "\\lambda_{1} = 1.0, \\lambda_{2} = 0.8, \\lambda_{3} = 0.25" + }, + { + "bbox": [ + 296, + 106, + 530, + 140 + ], + "type": "text", + "content": ". The total loss for training our encoder and the canonical latent discriminator can be written as:" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 317, + 145, + 530, + 159 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 145, + 530, + 159 + ], + "spans": [ + { + "bbox": [ + 317, + 145, + 530, + 159 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {t o t a l}} ^ {E} = \\mathcal {L} _ {\\mathrm {a d v}} ^ {\\mathcal {D} w _ {c}} + \\lambda_ {4} \\mathcal {L} _ {\\mathrm {a d v}} ^ {E} + \\lambda_ {5} \\mathcal {L} _ {B G} + \\mathcal {L} _ {\\text {r e c}}, \\tag {11}", + "image_path": "009d8059676c43643329fd6e992d327613d833e29a9873510b8cbe36ac1efcc1.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "spans": [ + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "inline_equation", + "content": "R_{1}" + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "text", + "content": " regularization weight " + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "inline_equation", + "content": "\\gamma = 10" + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "inline_equation", + "content": "\\lambda_4 = 0.05" + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "inline_equation", + "content": "\\lambda_5 = 5.0" + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "text", + "content": ". Moreover, we apply regularization on " + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "inline_equation", + "content": "\\Delta w^{+} = (w_{1} - w_{0}, w_{2} - w_{0}, \\dots, w_{13} - w_{0})" + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "text", + "content": " by " + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_2" + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "text", + "content": " norm, i.e. " + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{w^+} = \\lambda_6\\| \\Delta w^+\\|_2" + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "inline_equation", + "content": "\\lambda_6 = 0.001" + }, + { + "bbox": [ + 296, + 164, + 530, + 211 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "spans": [ + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "type": "text", + "content": "Once the loss in the first stage is converged, we freeze the encoder parameters and drop the canonical latent discriminator and losses " + }, + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{adv}}^{\\mathcal{D}_{\\mathcal{W}_c}},\\mathcal{L}_{\\mathrm{adv}}^E,\\mathcal{L}_{w^+}" + }, + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "type": "text", + "content": ", but add a " + }, + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_2" + }, + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "type": "text", + "content": " regularization on " + }, + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "type": "inline_equation", + "content": "\\Delta F = F^{*} - F" + }, + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "type": "inline_equation", + "content": "\\lambda_7 = 0.0001" + }, + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "type": "text", + "content": " for training the AFA module, i.e. " + }, + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\Delta F} = \\lambda_7\\| \\Delta F\\| _2" + }, + { + "bbox": [ + 296, + 211, + 530, + 282 + ], + "type": "text", + "content": ". We apply the loss settings to both human data and cat data." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 296, + 282, + 530, + 316 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 282, + 530, + 316 + ], + "spans": [ + { + "bbox": [ + 296, + 282, + 530, + 316 + ], + "type": "text", + "content": "For re-implemented pSp [35] and e4e [42], we train it with the same loss weight in our settings, and train them until the losses converge." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 297, + 325, + 376, + 339 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 325, + 376, + 339 + ], + "spans": [ + { + "bbox": [ + 297, + 325, + 376, + 339 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 296, + 345, + 530, + 436 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 345, + 530, + 436 + ], + "spans": [ + { + "bbox": [ + 296, + 345, + 530, + 436 + ], + "type": "text", + "content": "Experiment setup. We evaluate our method on human faces and cat faces. For human faces, we use FFHQ [1] dataset for training, and CelebA-HQ [18] and MEAD [44] for evaluation. For the cat faces, we use AFHQ-CAT [7] for training and evaluation. In addition, we employ the pretrained EG3D generator and obtain the corresponding camera parameters of each image following the official implementation in EG3D." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 296, + 437, + 530, + 508 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 437, + 530, + 508 + ], + "spans": [ + { + "bbox": [ + 296, + 437, + 530, + 508 + ], + "type": "text", + "content": "Baselines. We compare our method with encoder (IDE-3D [40]) and optimization-based (PTI [36] and Pose Opt. [21]) baselines in these two aspects. Moreover, we build two encoder baselines imitating the state-of-the-art StyleGAN inverters, pSp [35] and e4e [42], and present the model structure in the supplementary." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 297, + 513, + 409, + 526 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 513, + 409, + 526 + ], + "spans": [ + { + "bbox": [ + 297, + 513, + 409, + 526 + ], + "type": "text", + "content": "5.1. Qualitative analysis" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 296, + 531, + 530, + 588 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 531, + 530, + 588 + ], + "spans": [ + { + "bbox": [ + 296, + 531, + 530, + 588 + ], + "type": "text", + "content": "Source View Inversion Results. Fig. 6 shows the inversion performance comparison between ours and other methods. Our method's hair details and facial similarity are obviously competitive with optimization methods and surpass all the encoder-based methods." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 296, + 589, + 530, + 682 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 589, + 530, + 682 + ], + "spans": [ + { + "bbox": [ + 296, + 589, + 530, + 682 + ], + "type": "text", + "content": "Novel View Synthesis Results. The comparison results are shown in Fig. 6. Inspecting the eye gaze direction and person's identity preservation when changing to novel views can reveal the differences. It can be seen that on some extreme side-face camera poses, some optimization methods produce artifacts and geometry distortions. Our method can keep synthesizing 3D-consistent images faithful to the person's identity in the input." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 297, + 688, + 415, + 700 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 688, + 415, + 700 + ], + "spans": [ + { + "bbox": [ + 297, + 688, + 415, + 700 + ], + "type": "text", + "content": "5.2.Quantitative analysis" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 297, + 706, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 706, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 297, + 706, + 530, + 730 + ], + "type": "text", + "content": "We calculate the mean square error (MSE), LPIPS [50], and FID [16] between the source image and its inversion." + } + ] + } + ], + "index": 26 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "spans": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "text", + "content": "2442" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 71, + 103, + 505, + 365 + ], + "blocks": [ + { + "bbox": [ + 71, + 103, + 505, + 365 + ], + "lines": [ + { + "bbox": [ + 71, + 103, + 505, + 365 + ], + "spans": [ + { + "bbox": [ + 71, + 103, + 505, + 365 + ], + "type": "image", + "image_path": "e2aedef42d3dfd5ad3f27e244d833b216f9797f8614bd06b88fc97cd5145c3ef.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 368, + 533, + 405 + ], + "lines": [ + { + "bbox": [ + 45, + 368, + 533, + 405 + ], + "spans": [ + { + "bbox": [ + 45, + 368, + 533, + 405 + ], + "type": "text", + "content": "Figure 6: Visual comparison of inversion and novel-view synthesized results between our method and others. Our method surpasses all the encoder-based methods and is competitive with optimization methods in recovering texture details, i.e., our method prevents the eye orientation from changing with the camera view and artifacts in the novel view." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 48, + 415, + 531, + 517 + ], + "blocks": [ + { + "bbox": [ + 48, + 415, + 531, + 517 + ], + "lines": [ + { + "bbox": [ + 48, + 415, + 531, + 517 + ], + "spans": [ + { + "bbox": [ + 48, + 415, + 531, + 517 + ], + "type": "table", + "html": "
CategoryMethodReconstruction QualityNovel View Quality
Input Viewyaw=±60°yaw=0°
MSE ↓LPIPS ↓FID ↓ID ↑Geo. Err. ↓Time (s) ↓LPIPS ↓FID ↓ID ↑Geo. Err. ↓LPIPS ↓FID ↓ID ↑Geo. Err. ↓
OptimizationPTI [36]0.01630.091818.00.84170.0850115.20.292669.80.6210.14810.192553.50.7180.1006
Pose Opt. [21]0.01640.087917.50.83900.0759219.70.44771320.3210.17630.243660.20.6050.1504
Encoder-basedIDE-3D [40]0.10560.280643.60.71940.18350.06590.331779.00.5050.29140.307463.70.5130.2528
pSp-3D [35]0.07260.208231.20.78170.18460.12840.322365.70.5910.12870.313265.20.6710.1789
e4e-3D [42]0.08080.228133.00.73590.11610.13030.249557.70.5880.12690.239453.80.6530.1305
Ours-w+0.06970.198130.90.78730.11000.09630.230352.20.6550.09430.237254.10.6850.0955
Ours0.03010.125720.50.87520.09870.22620.219250.90.7000.09500.220451.70.7430.0944
", + "image_path": "7ed9ca1a0815559e447bb0cdb84a25c49b0aff9b13e6e89f242325dd778c6b33.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 525, + 532, + 563 + ], + "lines": [ + { + "bbox": [ + 45, + 525, + 532, + 563 + ], + "spans": [ + { + "bbox": [ + 45, + 525, + 532, + 563 + ], + "type": "text", + "content": "Table 1: Comparison with state-of-the-art methods on inversion performance. The numbers in bold are the best performance of the optimization and encoder-based methods, respectively. Metrics of Reconstruction Quality are calculated under the input view. Metrics of Novel View Quality are the average of multi-view. The yaw angle is the source view angle." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 45, + 580, + 280, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 580, + 280, + 676 + ], + "spans": [ + { + "bbox": [ + 45, + 580, + 280, + 676 + ], + "type": "text", + "content": "We adopt a pre-trained face key point detector parsenet [52] to calculate the identity similarity. To measure the geometry properties, we followed [5, 38], utilizing a pre-trained 3D face reconstruction model to extract a \"pseudo\" ground truth depth map from the source image. Then, we obtain the depth of inversion and normalize all depth maps to zero means and unit variance to calculate geometry error (Geo. Err.) by using average " + }, + { + "bbox": [ + 45, + 580, + 280, + 676 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_2" + }, + { + "bbox": [ + 45, + 580, + 280, + 676 + ], + "type": "text", + "content": " distance." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 682, + 281, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 682, + 281, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 682, + 281, + 730 + ], + "type": "text", + "content": "Source View Inversion Results. Table 1 presents the quantitative comparison of the input view image reconstruction on CelebA-HQ test dataset. Our method is two orders of magnitude faster than the optimized methods with similar" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 296, + 580, + 530, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 580, + 530, + 604 + ], + "spans": [ + { + "bbox": [ + 296, + 580, + 530, + 604 + ], + "type": "text", + "content": "performance, which is notably better than other encoder-based methods." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 296, + 612, + 531, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 612, + 531, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 612, + 531, + 730 + ], + "type": "text", + "content": "Novel View Synthesis Results. In order to measure the multi-view consistency and the synthesized quality, we evaluate our method and baselines with a multi-view dataset, MEAD [44]. Each person in MEAD has five images with increasing yaw angles. We select one angle as the input view, invert the input image and synthesize the other four novel views. Then we use the same metrics to calculate the difference between the synthesized images and the ground truth. The quantitative comparison between the novel view synthesized results and the ground truth in dif" + } + ] + } + ], + "index": 7 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "spans": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "text", + "content": "2443" + } + ] + } + ], + "index": 8 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 48, + 106, + 278, + 257 + ], + "blocks": [ + { + "bbox": [ + 48, + 106, + 278, + 257 + ], + "lines": [ + { + "bbox": [ + 48, + 106, + 278, + 257 + ], + "spans": [ + { + "bbox": [ + 48, + 106, + 278, + 257 + ], + "type": "image", + "image_path": "afc3c8a45e15f98589850b01d19d5a8f464c0808a207e00edd3903f4754095cb.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "lines": [ + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "spans": [ + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "type": "text", + "content": "Figure 7: Ablation of Geometry-aware Encoder. All images are synthesized only with " + }, + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "type": "text", + "content": ". Without both modules, " + }, + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "type": "text", + "content": " fails to generate integrated 3D geometry and texture. The " + }, + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "type": "inline_equation", + "content": "L_{BG}" + }, + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "type": "text", + "content": " helps distinguish foreground and background. With " + }, + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{\\mathcal{W}_c}" + }, + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "type": "text", + "content": ", we can get good inversion under the input view but fail under the novel view. With both modules, " + }, + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 45, + 266, + 280, + 360 + ], + "type": "text", + "content": " can obtain an integrated side face of the woman, which is occlusion under the input view." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 45, + 373, + 279, + 466 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 373, + 279, + 466 + ], + "spans": [ + { + "bbox": [ + 45, + 373, + 279, + 466 + ], + "type": "text", + "content": "ferent views is shown in Table 1. Our method shows similar performance with PTI when the input image is a front face " + }, + { + "bbox": [ + 45, + 373, + 279, + 466 + ], + "type": "inline_equation", + "content": "(\\mathrm{yaw} = 0^{\\circ})" + }, + { + "bbox": [ + 45, + 373, + 279, + 466 + ], + "type": "text", + "content": ". When inverting side faces, the difficulty of inversion increases drastically when the yaw angle increases. We calculated the metrics of the largest yaw angle in MEAD " + }, + { + "bbox": [ + 45, + 373, + 279, + 466 + ], + "type": "inline_equation", + "content": "(\\mathrm{yaw} = \\pm 60^{\\circ})" + }, + { + "bbox": [ + 45, + 373, + 279, + 466 + ], + "type": "text", + "content": ", and our model has robust performance when the test yaw angle varies. However, the performance of optimization methods degrades remarkably at an extreme angle." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 476, + 149, + 488 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 476, + 149, + 488 + ], + "spans": [ + { + "bbox": [ + 45, + 476, + 149, + 488 + ], + "type": "text", + "content": "5.3. Ablation Analysis" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 45, + 495, + 279, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 495, + 279, + 529 + ], + "spans": [ + { + "bbox": [ + 45, + 495, + 279, + 529 + ], + "type": "text", + "content": "We present ablation studies with qualitative analysis of our proposed method below, and the corresponding numerical ablation results are in our supplementary." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 530, + 279, + 635 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 530, + 279, + 635 + ], + "spans": [ + { + "bbox": [ + 45, + 530, + 279, + 635 + ], + "type": "text", + "content": "Geometry-aware Encoder. We conduct ablation experiments and make qualitative comparisons to verify that our proposed canonical latent discriminator " + }, + { + "bbox": [ + 45, + 530, + 279, + 635 + ], + "type": "inline_equation", + "content": "(\\mathcal{D}_{\\mathcal{W}_c})" + }, + { + "bbox": [ + 45, + 530, + 279, + 635 + ], + "type": "text", + "content": " and background regularization " + }, + { + "bbox": [ + 45, + 530, + 279, + 635 + ], + "type": "inline_equation", + "content": "(\\mathcal{L}_{BG})" + }, + { + "bbox": [ + 45, + 530, + 279, + 635 + ], + "type": "text", + "content": " contribute to restoring 3D geometry. Generally, recovering the geometry from a side face input is more challenging and we test such a case. As shown in Fig. 7, only if we adopt the canonical discriminator and the background regularization could we obtain a satisfactory foreground and background geometry." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 635, + 279, + 682 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 635, + 279, + 682 + ], + "spans": [ + { + "bbox": [ + 45, + 635, + 279, + 682 + ], + "type": "text", + "content": "Adaptive Feature Alignment. We proposed Adaptive Feature Alignment (AFA) to refine the " + }, + { + "bbox": [ + 45, + 635, + 279, + 682 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 45, + 635, + 279, + 682 + ], + "type": "text", + "content": " latent map and add texture details from the source view. Fig. 8 demonstrates that we can recover more details with AFA." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 45, + 682, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 682, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 682, + 279, + 730 + ], + "type": "text", + "content": "Occlusion-aware Mix Tri-plane. To verify the necessity of our proposed occlusion-aware mix tri-plane, we ablate this operation and visualize the novel view results in Fig. 9. The occlusion map shows the spatial position of surface points" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 299, + 105, + 414, + 150 + ], + "blocks": [ + { + "bbox": [ + 299, + 105, + 414, + 150 + ], + "lines": [ + { + "bbox": [ + 299, + 105, + 414, + 150 + ], + "spans": [ + { + "bbox": [ + 299, + 105, + 414, + 150 + ], + "type": "image", + "image_path": "02bd75f9518dbefc9cff5c37265c55a26824a8b6103f1a00864d81db79de6410.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 296, + 154, + 530, + 200 + ], + "lines": [ + { + "bbox": [ + 296, + 154, + 530, + 200 + ], + "spans": [ + { + "bbox": [ + 296, + 154, + 530, + 200 + ], + "type": "text", + "content": "Figure 8: Ablation of Adaptive Feature Alignment. We replace AFA with a CNN network and obtain the results. Without feature alignment, it is difficult to reconstruct the hair and facial details." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 415, + 105, + 529, + 149 + ], + "blocks": [ + { + "bbox": [ + 415, + 105, + 529, + 149 + ], + "lines": [ + { + "bbox": [ + 415, + 105, + 529, + 149 + ], + "spans": [ + { + "bbox": [ + 415, + 105, + 529, + 149 + ], + "type": "image", + "image_path": "7adb34605baa08408b4fc2ea44bd3c6b22a1997e5a1bd72712d05fc7125d63f5.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 299, + 203, + 530, + 327 + ], + "blocks": [ + { + "bbox": [ + 299, + 203, + 530, + 327 + ], + "lines": [ + { + "bbox": [ + 299, + 203, + 530, + 327 + ], + "spans": [ + { + "bbox": [ + 299, + 203, + 530, + 327 + ], + "type": "image", + "image_path": "bd1412f2e7b937d752ef20e257b2b0a8f83c0ed011341d344c2e8dc0ad8182e6.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 296, + 332, + 530, + 390 + ], + "lines": [ + { + "bbox": [ + 296, + 332, + 530, + 390 + ], + "spans": [ + { + "bbox": [ + 296, + 332, + 530, + 390 + ], + "type": "text", + "content": "Figure 9: Ablation of Occlusion-aware mix tri-plane. We visualize the occlusion regions " + }, + { + "bbox": [ + 296, + 332, + 530, + 390 + ], + "type": "inline_equation", + "content": "\\mathcal{O}_{(x,y,z)}" + }, + { + "bbox": [ + 296, + 332, + 530, + 390 + ], + "type": "text", + "content": " of the input view in the last column (black points). The green arrow points out " + }, + { + "bbox": [ + 296, + 332, + 530, + 390 + ], + "type": "inline_equation", + "content": "\\mathcal{O}_{(x,y,z)}" + }, + { + "bbox": [ + 296, + 332, + 530, + 390 + ], + "type": "text", + "content": " in the novel view, and it is obvious that the occlusion-aware mix tri-plane can avoid artifacts." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 299, + 394, + 530, + 570 + ], + "blocks": [ + { + "bbox": [ + 299, + 394, + 530, + 570 + ], + "lines": [ + { + "bbox": [ + 299, + 394, + 530, + 570 + ], + "spans": [ + { + "bbox": [ + 299, + 394, + 530, + 570 + ], + "type": "image", + "image_path": "c1f26b2e765a19c8c7b24a1e0582fe0bcbc967fa3d287666524b2c8a77e89703.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 296, + 575, + 530, + 610 + ], + "lines": [ + { + "bbox": [ + 296, + 575, + 530, + 610 + ], + "spans": [ + { + "bbox": [ + 296, + 575, + 530, + 610 + ], + "type": "text", + "content": "Figure 10: Editing result under novel views. We add three different attributes to three faces. Our method generates both realistic editing and 3D-consistent novel views." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "bbox": [ + 296, + 623, + 530, + 669 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 623, + 530, + 669 + ], + "spans": [ + { + "bbox": [ + 296, + 623, + 530, + 669 + ], + "type": "text", + "content": "in ray sampling, the visible region in the original view is white, and the occlusion region is black. Without the mix tri-plane, the occlusion area from the source view is easy to produce artifacts in novel views." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 297, + 676, + 420, + 688 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 676, + 420, + 688 + ], + "spans": [ + { + "bbox": [ + 297, + 676, + 420, + 688 + ], + "type": "text", + "content": "5.4. Image Editing Results" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 296, + 694, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 694, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 694, + 530, + 730 + ], + "type": "text", + "content": "In GAN inversion-based image manipulation, the editability and the reconstruction trade-off widely exists in both 2D and 3D scenarios. We validate the editing method" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "spans": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "text", + "content": "2444" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 46, + 103, + 532, + 220 + ], + "blocks": [ + { + "bbox": [ + 46, + 103, + 532, + 220 + ], + "lines": [ + { + "bbox": [ + 46, + 103, + 532, + 220 + ], + "spans": [ + { + "bbox": [ + 46, + 103, + 532, + 220 + ], + "type": "image", + "image_path": "dd3ce5e5ff80b88a81039421bb32462b9379d2ceb475a8b1590846ef195aa0ee.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 178, + 223, + 397, + 234 + ], + "lines": [ + { + "bbox": [ + 178, + 223, + 397, + 234 + ], + "spans": [ + { + "bbox": [ + 178, + 223, + 397, + 234 + ], + "type": "text", + "content": "Figure 11: Results of our encoder in other 3D GANs." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 47, + 239, + 278, + 262 + ], + "blocks": [ + { + "bbox": [ + 47, + 239, + 278, + 262 + ], + "lines": [ + { + "bbox": [ + 47, + 239, + 278, + 262 + ], + "spans": [ + { + "bbox": [ + 47, + 239, + 278, + 262 + ], + "type": "table", + "html": "
MSE ↓LPIPS ↓FID ↓MSE ↓LPIPS ↓FID ↓
w/o AFA0.05860.231713.43w/ AFA0.03670.174510.82
", + "image_path": "d5923d486c39afd4dda648367c316e3755cb99ab0d07da60fcec752063f7823b.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 69, + 265, + 256, + 277 + ], + "lines": [ + { + "bbox": [ + 69, + 265, + 256, + 277 + ], + "spans": [ + { + "bbox": [ + 69, + 265, + 256, + 277 + ], + "type": "text", + "content": "Table 2: Ablation of AFA on ShapeNet Cars." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 45, + 288, + 279, + 394 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 288, + 279, + 394 + ], + "spans": [ + { + "bbox": [ + 45, + 288, + 279, + 394 + ], + "type": "text", + "content": "mentioned in Sec. 4.4 and display the multi-view edited results in Fig. 10. We choose three different edit directions, 'Young' to reduce person's age, 'Unhappy' to change emotion, and 'Glasses' to add accessories. It is noticeable that our method not only restores the geometric and texture information of the input image but also ensures the editing consistency of multi-view. The edited results demonstrate that our inversion method can be well applied to the facial image editing tasks." + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 85, + 403, + 245, + 570 + ], + "blocks": [ + { + "bbox": [ + 85, + 403, + 245, + 570 + ], + "lines": [ + { + "bbox": [ + 85, + 403, + 245, + 570 + ], + "spans": [ + { + "bbox": [ + 85, + 403, + 245, + 570 + ], + "type": "image", + "image_path": "6b816134e4a44946b9b5ed091e2151b5ae6970cbc52852231505cebbc2bab88b.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 579, + 279, + 614 + ], + "lines": [ + { + "bbox": [ + 45, + 579, + 279, + 614 + ], + "spans": [ + { + "bbox": [ + 45, + 579, + 279, + 614 + ], + "type": "text", + "content": "Figure 12: (a) Tri-plane canonical feature space. (b) Results of our method on ShapeNet Cars datasets. Best viewed zoomed in and in color." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 623, + 135, + 635 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 623, + 135, + 635 + ], + "spans": [ + { + "bbox": [ + 45, + 623, + 135, + 635 + ], + "type": "text", + "content": "6. Generalization" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 45, + 642, + 279, + 690 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 642, + 279, + 690 + ], + "spans": [ + { + "bbox": [ + 45, + 642, + 279, + 690 + ], + "type": "text", + "content": "Our method can be adapted to other 3D GANs (e.g., EpiGRAF [39] and StyleSDF [32]) and it works also with categories where pose estimation and canonicalization are more difficult (e.g., Shapenet cars)." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 45, + 694, + 280, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 694, + 280, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 694, + 280, + 730 + ], + "type": "text", + "content": "Extension to other 3D GANs. We choose EG3D as our base 3D GAN due to its superior performance, but our method can also be applied to other 3D GANs. The canon-" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 241, + 530, + 405 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 241, + 530, + 405 + ], + "spans": [ + { + "bbox": [ + 296, + 241, + 530, + 405 + ], + "type": "text", + "content": "ical space, which plays a vital role in 3D GAN inversion, is commonly presented in the latent space (i.e., " + }, + { + "bbox": [ + 296, + 241, + 530, + 405 + ], + "type": "inline_equation", + "content": "w^{+}" + }, + { + "bbox": [ + 296, + 241, + 530, + 405 + ], + "type": "text", + "content": "space) of 3D GANs. By inverting images into the canonical space, we preserve geometry and achieve high-fidelity reconstruction, as demonstrated in our experiments on EpiGRAF [39] and StyleSDF [32] in Fig. 11. The results of w/o " + }, + { + "bbox": [ + 296, + 241, + 530, + 405 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{\\mathcal{W}_c}, L_{BG}" + }, + { + "bbox": [ + 296, + 241, + 530, + 405 + ], + "type": "text", + "content": " mean that we only use the base encoder without the canonical latent discriminator and the background depth regularization. In contrast, w/ " + }, + { + "bbox": [ + 296, + 241, + 530, + 405 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{\\mathcal{W}_c}, L_{BG}" + }, + { + "bbox": [ + 296, + 241, + 530, + 405 + ], + "type": "text", + "content": " is our full encoder model. The noticeable performance gap proves the powerful inversion ability of our method. Our method explores the canonical space's characteristics, ensuring distortion-free shape generation and exceptional performance in image 3D inversion." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 410, + 531, + 491 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 410, + 531, + 491 + ], + "spans": [ + { + "bbox": [ + 296, + 410, + 531, + 491 + ], + "type": "text", + "content": "Extension to ShapeNet Cars. Fig. 12 shows (a) the canonical space and (b) the inversion results on ShapeNet Cars. Even without identity loss, our method can achieve good performance(see the Col.3,5 of (b)). As the tri-plane is canonical, without the AFA module, the residual feature can not align with the canonical feature space (see the Col. 2,4 of (b) and Table 2)." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 297, + 493, + 368, + 505 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 493, + 368, + 505 + ], + "spans": [ + { + "bbox": [ + 297, + 493, + 368, + 505 + ], + "type": "text", + "content": "7. Conclusion" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 507, + 530, + 658 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 507, + 530, + 658 + ], + "spans": [ + { + "bbox": [ + 296, + 507, + 530, + 658 + ], + "type": "text", + "content": "In this work, we explore the inherent property of EG3D's latent space and find that the key to achieve high-quality shape and texture inversion is inverting input images to the canonical space. In light of this, we design an efficient geometry-aware encoder with an adaptive feature alignment module and demonstrate their effectiveness. Besides, we propose an occlusion-aware mix tri-plane to avoid invisible region distortion in novel views. Extensive experiments demonstrate that our method has competitive inversion performance with optimization-based methods, but operates two orders of magnitude faster. In addition, our method is demonstrated to be a powerful tool for realistic and 3D view-consistent editing of facial images." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 297, + 660, + 405, + 672 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 660, + 405, + 672 + ], + "spans": [ + { + "bbox": [ + 297, + 660, + 405, + 672 + ], + "type": "text", + "content": "8. Acknowledgement" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 296, + 671, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 671, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 671, + 530, + 730 + ], + "type": "text", + "content": "This work was supported by the National Key R&D Program of China (2022YFB4701400/4701402), SZSTC Grant (JCYJ20190809172201639, WDZC20200820200655001), Shenzhen Key Laboratory (ZDSYS20210623092001004), and Beijing Key Lab of Networked Multimedia." + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "spans": [ + { + "bbox": [ + 279, + 746, + 298, + 756 + ], + "type": "text", + "content": "2445" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 105, + 102, + 117 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 105, + 102, + 117 + ], + "spans": [ + { + "bbox": [ + 47, + 105, + 102, + 117 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 124, + 280, + 730 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 51, + 124, + 279, + 167 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 124, + 279, + 167 + ], + "spans": [ + { + "bbox": [ + 51, + 124, + 279, + 167 + ], + "type": "text", + "content": "[1] Rameen Abdul, Yipeng Qin, and Peter Wonka. Image2stylegan: How to embed images into the stylegan latent space? In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4432-4441, 2019. 3, 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 51, + 168, + 280, + 210 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 168, + 280, + 210 + ], + "spans": [ + { + "bbox": [ + 51, + 168, + 280, + 210 + ], + "type": "text", + "content": "[2] Yuval Alaluf, Or Patashnik, and Daniel Cohen-Or. Restyle: A residual-based stylegan encoder via iterative refinement. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6711–6720, 2021. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 51, + 211, + 280, + 265 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 211, + 280, + 265 + ], + "spans": [ + { + "bbox": [ + 51, + 211, + 280, + 265 + ], + "type": "text", + "content": "[3] Yuval Alaluf, Omer Tov, Ron Mokady, Rinon Gal, and Amit Bermano. Hyperstyle: Stylegan inversion with hypernetworks for real image editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18511-18521, 2022. 2, 5" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 51, + 265, + 279, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 265, + 279, + 308 + ], + "spans": [ + { + "bbox": [ + 51, + 265, + 279, + 308 + ], + "type": "text", + "content": "[4] Lucy Chai, Jun-Yan Zhu, Eli Shechtman, Phillip Isola, and Richard Zhang. Ensembling with deep generative views. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14997-15007, 2021. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 51, + 309, + 279, + 372 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 309, + 279, + 372 + ], + "spans": [ + { + "bbox": [ + 51, + 309, + 279, + 372 + ], + "type": "text", + "content": "[5] Eric R Chan, Connor Z Lin, Matthew A Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas J Guibas, Jonathan Tremblay, Sameh Khamis, et al. Efficient geometry-aware 3d generative adversarial networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 16123-16133, 2022. 1, 2, 7" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 51, + 373, + 279, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 373, + 279, + 426 + ], + "spans": [ + { + "bbox": [ + 51, + 373, + 279, + 426 + ], + "type": "text", + "content": "[6] Eric R Chan, Marco Monteiro, Petr Kellnhofer, Jiajun Wu, and Gordon Wetzstein. pi-gan: Periodic implicit generative adversarial networks for 3d-aware image synthesis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5799-5809, 2021. 1, 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 51, + 427, + 279, + 469 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 427, + 279, + 469 + ], + "spans": [ + { + "bbox": [ + 51, + 427, + 279, + 469 + ], + "type": "text", + "content": "[7] Yunjoy Choi, Youngjung Uh, Jaejun Yoo, and Jung-Woo Ha. Stargan v2: Diverse image synthesis for multiple domains. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8188-8197, 2020. 6" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 51, + 470, + 279, + 512 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 470, + 279, + 512 + ], + "spans": [ + { + "bbox": [ + 51, + 470, + 279, + 512 + ], + "type": "text", + "content": "[8] Edo Collins, Raja Bala, Bob Price, and Sabine Susstrunk. Editing in style: Uncovering the local semantics of gans. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5771-5780, 2020. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 51, + 513, + 279, + 566 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 513, + 279, + 566 + ], + "spans": [ + { + "bbox": [ + 51, + 513, + 279, + 566 + ], + "type": "text", + "content": "[9] Jiankang Deng, Jia Guo, Niannan Xue, and Stefanos Zafeiriou. Arcface: Additive angular margin loss for deep face recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4690-4699, 2019. 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 567, + 279, + 619 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 567, + 279, + 619 + ], + "spans": [ + { + "bbox": [ + 47, + 567, + 279, + 619 + ], + "type": "text", + "content": "[10] Yu Deng, Jiaolong Yang, Jianfeng Xiang, and Xin Tong. Gram: Generative radiance manifolds for 3d-aware image generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10673-10683, 2022. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 621, + 279, + 673 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 621, + 279, + 673 + ], + "spans": [ + { + "bbox": [ + 47, + 621, + 279, + 673 + ], + "type": "text", + "content": "[11] Tan M Dinh, Anh Tuan Tran, Rang Nguyen, and Binh-Son Hua. Hyperinverter: Improving stylegan inversion via hypernetwork. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11389-11398, 2022. 2, 5" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 675, + 279, + 708 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 675, + 279, + 708 + ], + "spans": [ + { + "bbox": [ + 47, + 675, + 279, + 708 + ], + "type": "text", + "content": "[12] Shubham Goel, Angjoo Kanazawa, and Jitendra Malik. Shape and viewpoint without keypoints. In European Conference on Computer Vision, 2020. 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 47, + 708, + 279, + 730 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 708, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 47, + 708, + 279, + 730 + ], + "type": "text", + "content": "[13] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 299, + 106, + 530, + 730 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 317, + 106, + 530, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 106, + 530, + 128 + ], + "spans": [ + { + "bbox": [ + 317, + 106, + 530, + 128 + ], + "type": "text", + "content": "Yoshua Bengio. Generative adversarial nets. In Advances in Neural Information Processing Systems, 2014. 2, 4" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 299, + 129, + 530, + 171 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 129, + 530, + 171 + ], + "spans": [ + { + "bbox": [ + 299, + 129, + 530, + 171 + ], + "type": "text", + "content": "[14] Jiatao Gu, Lingjie Liu, Peng Wang, and Christian Theobalt. Stylenerf: A style-based 3d-aware generator for high-resolution image synthesis. arXiv preprint arXiv:2110.08985, 2021. 1, 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 299, + 173, + 530, + 215 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 173, + 530, + 215 + ], + "spans": [ + { + "bbox": [ + 299, + 173, + 530, + 215 + ], + "type": "text", + "content": "[15] Paul Henderson, Vagia Tsiminaki, and Christoph H Lampert. Leveraging 2d data to learn textured 3d mesh generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 299, + 217, + 530, + 269 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 217, + 530, + 269 + ], + "spans": [ + { + "bbox": [ + 299, + 217, + 530, + 269 + ], + "type": "text", + "content": "[16] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in Neural Information Processing Systems, 30, 2017. 6" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 299, + 271, + 530, + 314 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 271, + 530, + 314 + ], + "spans": [ + { + "bbox": [ + 299, + 271, + 530, + 314 + ], + "type": "text", + "content": "[17] Angjoo Kanazawa, Shubham Tulsiani, Alexei A. Efros, and Jitendra Malik. Learning category-specific mesh reconstruction from image collections. In European Conference on Computer Vision, 2018. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 299, + 314, + 530, + 357 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 314, + 530, + 357 + ], + "spans": [ + { + "bbox": [ + 299, + 314, + 530, + 357 + ], + "type": "text", + "content": "[18] Tero Karras, Timo Aila, Samuli Laine, and Jaakko Lehtinen. Progressive growing of GANs for improved quality, stability, and variation. In International Conference On Learning Representations, 2018. 6" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 299, + 358, + 530, + 400 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 358, + 530, + 400 + ], + "spans": [ + { + "bbox": [ + 299, + 358, + 530, + 400 + ], + "type": "text", + "content": "[19] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2019. 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 299, + 402, + 530, + 454 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 402, + 530, + 454 + ], + "spans": [ + { + "bbox": [ + 299, + 402, + 530, + 454 + ], + "type": "text", + "content": "[20] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of StyleGAN. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2020. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 299, + 456, + 530, + 488 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 456, + 530, + 488 + ], + "spans": [ + { + "bbox": [ + 299, + 456, + 530, + 488 + ], + "type": "text", + "content": "[21] Jaehoon Ko, Kyusun Cho, Daewon Choi, Kwangrok Ryoo, and Seungryong Kim. 3d gan inversion with pose optimization. arXiv preprint arXiv:2210.07301, 2022. 1, 3, 6, 7" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 299, + 489, + 530, + 531 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 489, + 530, + 531 + ], + "spans": [ + { + "bbox": [ + 299, + 489, + 530, + 531 + ], + "type": "text", + "content": "[22] Yushi Lan, Xuyi Meng, Shuai Yang, Chen Change Loy, and Bo Dai. Self-supervised geometry-aware encoder for style-based 3d gan inversion. arXiv preprint arXiv:2212.07409, 2022. 2, 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 299, + 532, + 530, + 575 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 532, + 530, + 575 + ], + "spans": [ + { + "bbox": [ + 299, + 532, + 530, + 575 + ], + "type": "text", + "content": "[23] Yu-Jhe Li, Tao Xu, Bichen Wu, Ningyuan Zheng, Xiaoliang Dai, Albert Pumarola, Peizhao Zhang, Peter Vajda, and Kris Kitani. 3d-aware encoding for style-based neural radiance fields. arXiv preprint arXiv:2211.06583, 2022. 2, 3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 299, + 576, + 530, + 608 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 576, + 530, + 608 + ], + "spans": [ + { + "bbox": [ + 299, + 576, + 530, + 608 + ], + "type": "text", + "content": "[24] Hongyu Liu, Yibing Song, and Qifeng Chen. Delving stylegan inversion for image editing: A foundation latent space viewpoint. arXiv preprint arXiv:2211.11448, 2022. 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 299, + 609, + 530, + 663 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 609, + 530, + 663 + ], + "spans": [ + { + "bbox": [ + 299, + 609, + 530, + 663 + ], + "type": "text", + "content": "[25] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10012-10022, 2021. 4" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 299, + 664, + 530, + 706 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 664, + 530, + 706 + ], + "spans": [ + { + "bbox": [ + 299, + 664, + 530, + 706 + ], + "type": "text", + "content": "[26] Lars Mescheder, Andreas Geiger, and Sebastian Nowozin. Which training methods for gans do actually converge? In International Conference on Machine Learning, pages 3481-3490. PMLR, 2018. 4" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 299, + 707, + 530, + 730 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 707, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 299, + 707, + 530, + 730 + ], + "type": "text", + "content": "[27] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf:" + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 747, + 298, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 747, + 298, + 756 + ], + "spans": [ + { + "bbox": [ + 279, + 747, + 298, + 756 + ], + "type": "text", + "content": "2446" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 106, + 279, + 729 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 65, + 106, + 279, + 138 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 106, + 279, + 138 + ], + "spans": [ + { + "bbox": [ + 65, + 106, + 279, + 138 + ], + "type": "text", + "content": "Representing scenes as neural radiance fields for view synthesis. In European Conference on Computer Vision, 2020. 1, 2, 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 139, + 279, + 191 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 139, + 279, + 191 + ], + "spans": [ + { + "bbox": [ + 47, + 139, + 279, + 191 + ], + "type": "text", + "content": "[28] Thu Nguyen-Phuoc, Chuan Li, Lucas Theis, Christian Richardt, and Yong-Liang Yang. Hologan: Unsupervised learning of 3d representations from natural images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7588-7597, 2019. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 193, + 279, + 245 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 193, + 279, + 245 + ], + "spans": [ + { + "bbox": [ + 48, + 193, + 279, + 245 + ], + "type": "text", + "content": "[29] Thu H Nguyen-Phuoc, Christian Richardt, Long Mai, Yongliang Yang, and Niloy Mitra. Blockgan: Learning 3d object-aware scene representations from unlabelled images. Advances in Neural Information Processing Systems, 33:6767-6778, 2020. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 247, + 279, + 298 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 247, + 279, + 298 + ], + "spans": [ + { + "bbox": [ + 48, + 247, + 279, + 298 + ], + "type": "text", + "content": "[30] Michael Niemeyer and Andreas Geiger. Giraffe: Representing scenes as compositional generative neural feature fields. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11453-11464, 2021. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 300, + 279, + 332 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 300, + 279, + 332 + ], + "spans": [ + { + "bbox": [ + 48, + 300, + 279, + 332 + ], + "type": "text", + "content": "[31] Yotam Nitzan, Amit Bermano, Yangyan Li, and Daniel Cohen-Or. Face identity disentanglement via latent space mapping. arXiv preprint arXiv:2005.07728, 2020. 4" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 333, + 279, + 395 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 333, + 279, + 395 + ], + "spans": [ + { + "bbox": [ + 48, + 333, + 279, + 395 + ], + "type": "text", + "content": "[32] Roy Or-El, Xuan Luo, Mengyi Shan, Eli Shechtman, Jeong Joon Park, and Ira Kemelmacher-Shlizerman. Stylesdf: High-resolution 3d-consistent image and geometry generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13503–13513, 2022. 1, 2, 9" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 397, + 279, + 449 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 397, + 279, + 449 + ], + "spans": [ + { + "bbox": [ + 48, + 397, + 279, + 449 + ], + "type": "text", + "content": "[33] Or Patashnik, Zongze Wu, Eli Shechtman, Daniel Cohen-Or, and Dani Lischinski. Styleclip: Text-driven manipulation of stylegan imagery. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2085–2094, 2021. 3, 6" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 451, + 279, + 492 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 451, + 279, + 492 + ], + "spans": [ + { + "bbox": [ + 48, + 451, + 279, + 492 + ], + "type": "text", + "content": "[34] Ethan Perez, Florian Strub, Harm De Vries, Vincent Dumoulin, and Aaron Courville. Film: Visual reasoning with a general conditioning layer. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 32, 2018. 5" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 494, + 279, + 556 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 494, + 279, + 556 + ], + "spans": [ + { + "bbox": [ + 48, + 494, + 279, + 556 + ], + "type": "text", + "content": "[35] Elad Richardson, Yuval Alaluf, Or Patashnik, Yotam Nitzan, Yaniv Azar, Stav Shapiro, and Daniel Cohen-Or. Encoding in style: a stylegan encoder for image-to-image translation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2287–2296, 2021. 3, 4, 5, 6, 7" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 558, + 279, + 599 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 558, + 279, + 599 + ], + "spans": [ + { + "bbox": [ + 48, + 558, + 279, + 599 + ], + "type": "text", + "content": "[36] Daniel Roich, Ron Mokady, Amit H Bermano, and Daniel Cohen-Or. Pivotal tuning for latent-based editing of real images. ACM Transactions on Graphics (TOG), 42(1):1-13, 2022. 3, 6, 7" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 601, + 279, + 652 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 601, + 279, + 652 + ], + "spans": [ + { + "bbox": [ + 48, + 601, + 279, + 652 + ], + "type": "text", + "content": "[37] Yujun Shen, Jinjin Gu, Xiaou Tang, and Bolei Zhou. Interpreting the latent space of gans for semantic face editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9243-9252, 2020. 3, 6" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 655, + 279, + 697 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 655, + 279, + 697 + ], + "spans": [ + { + "bbox": [ + 48, + 655, + 279, + 697 + ], + "type": "text", + "content": "[38] Yichun Shi, Divyansh Aggarwal, and Anil K Jain. Lifting 2d stylegan for 3d-aware face generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 6258-6266, 2021. 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 698, + 279, + 729 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 698, + 279, + 729 + ], + "spans": [ + { + "bbox": [ + 48, + 698, + 279, + 729 + ], + "type": "text", + "content": "[39] Ivan Skorokhodov, Sergey Tulyakov, Yiqun Wang, and Peter Wonka. Epigraph: Rethinking training of 3d gans. arXiv preprint arXiv:2206.10535, 2022. 9" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 299, + 107, + 530, + 714 + ], + "type": "list", + "angle": 0, + "index": 27, + "blocks": [ + { + "bbox": [ + 299, + 107, + 530, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 107, + 530, + 149 + ], + "spans": [ + { + "bbox": [ + 299, + 107, + 530, + 149 + ], + "type": "text", + "content": "[40] Jingxiang Sun, Xuan Wang, Yichun Shi, Lizhen Wang, Jue Wang, and Yebin Liu. Ide-3d: Interactive disentangled editing for high-resolution 3d-aware portrait synthesis. arXiv preprint arXiv:2205.15517, 2022. 3, 6, 7" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 299, + 151, + 530, + 191 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 151, + 530, + 191 + ], + "spans": [ + { + "bbox": [ + 299, + 151, + 530, + 191 + ], + "type": "text", + "content": "[41] Maxim Tatarchenko, Alexey Dosovitskiy, and Thomas Brox. Multi-view 3D models from single images with a convolutional network. In European Conference on Computer Vision, 2016. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 299, + 194, + 530, + 235 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 194, + 530, + 235 + ], + "spans": [ + { + "bbox": [ + 299, + 194, + 530, + 235 + ], + "type": "text", + "content": "[42] Omer Tov, Yuval Alaluf, Yotam Nitzan, Or Patashnik, and Daniel Cohen-Or. Designing an encoder for stylegan image manipulation. ACM Transactions on Graphics (TOG), 40(4):1-14, 2021. 2, 3, 4, 6, 7" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 299, + 238, + 530, + 289 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 238, + 530, + 289 + ], + "spans": [ + { + "bbox": [ + 299, + 238, + 530, + 289 + ], + "type": "text", + "content": "[43] Shubham Tulsiani, Hao Su, Leonidas J. Guibas, Alexei A. Efros, and Jitendra Malik. Learning shape abstractions by assembling volumetric primitives. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2017. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 299, + 292, + 530, + 345 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 292, + 530, + 345 + ], + "spans": [ + { + "bbox": [ + 299, + 292, + 530, + 345 + ], + "type": "text", + "content": "[44] Kaisiyuan Wang, Qianyi Wu, Linsen Song, Zhuoqian Yang, Wayne Wu, Chen Qian, Ran He, Yu Qiao, and Chen Change Loy. Mead: A large-scale audio-visual dataset for emotional talking-face generation. In European Conference on Computer Vision, pages 700–717. Springer, 2020. 6, 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 299, + 346, + 530, + 398 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 346, + 530, + 398 + ], + "spans": [ + { + "bbox": [ + 299, + 346, + 530, + 398 + ], + "type": "text", + "content": "[45] Tengfei Wang, Yong Zhang, Yanbo Fan, Jue Wang, and Qifeng Chen. High-fidelity gan inversion for image attribute editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11379-11388, 2022. 2, 5" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 299, + 400, + 530, + 452 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 400, + 530, + 452 + ], + "spans": [ + { + "bbox": [ + 299, + 400, + 530, + 452 + ], + "type": "text", + "content": "[46] Zongze Wu, Dani Lischinski, and Eli Shechtman. Stylespace analysis: Disentangled controls for stylegan image generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12863-12872, 2021. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 299, + 455, + 530, + 495 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 455, + 530, + 495 + ], + "spans": [ + { + "bbox": [ + 299, + 455, + 530, + 495 + ], + "type": "text", + "content": "[47] Jiaxin Xie, Hao Ouyang, Jingtan Piao, Chenyang Lei, and Qifeng Chen. High-fidelity 3d gan inversion by pseudomulti-view optimization. arXiv preprint arXiv:2211.15662, 2022.1.3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 299, + 499, + 530, + 540 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 499, + 530, + 540 + ], + "spans": [ + { + "bbox": [ + 299, + 499, + 530, + 540 + ], + "type": "text", + "content": "[48] Xu Yao, Alasdair Newson, Yann Gousseau, and Pierre Hellier. A style-based gan encoder for high fidelity reconstruction of images and videos. European Conference on Computer Vision, 2022. 6" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 299, + 542, + 530, + 584 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 542, + 530, + 584 + ], + "spans": [ + { + "bbox": [ + 299, + 542, + 530, + 584 + ], + "type": "text", + "content": "[49] Fei Yin, Yong Zhang, Xuan Wang, Tengfei Wang, Xiaoyu Li, Yuan Gong, Yanbo Fan, Xiaodong Cun, Ying Shan, Cengiz Oztireli, et al. 3d gan inversion with facial symmetry prior. arXiv preprint arXiv:2211.16927, 2022. 1" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 299, + 586, + 530, + 639 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 586, + 530, + 639 + ], + "spans": [ + { + "bbox": [ + 299, + 586, + 530, + 639 + ], + "type": "text", + "content": "[50] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 586-595, 2018. 5, 6" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 299, + 640, + 530, + 681 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 640, + 530, + 681 + ], + "spans": [ + { + "bbox": [ + 299, + 640, + 530, + 681 + ], + "type": "text", + "content": "[51] Jiapeng Zhu, Yujun Shen, Deli Zhao, and Bolei Zhou. Indomain gan inversion for real image editing. In European Conference on Computer Vision, pages 592-608. Springer, 2020. 3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 299, + 683, + 528, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 683, + 528, + 714 + ], + "spans": [ + { + "bbox": [ + 299, + 683, + 528, + 714 + ], + "type": "text", + "content": "[52] zllrunning. faceParsing.pytorch. https://github.com/zllrunning/faceParsing.PyTorch/, 2019.4.7" + } + ] + } + ], + "index": 26 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 279, + 747, + 298, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 279, + 747, + 298, + 756 + ], + "spans": [ + { + "bbox": [ + 279, + 747, + 298, + 756 + ], + "type": "text", + "content": "2447" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/0b6ce6f5-40a5-4972-8f2c-3c7fc7288f3d_content_list.json b/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/0b6ce6f5-40a5-4972-8f2c-3c7fc7288f3d_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..a48093036c0eca8833cbdd2427689310637a14f1 --- /dev/null +++ b/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/0b6ce6f5-40a5-4972-8f2c-3c7fc7288f3d_content_list.json @@ -0,0 +1,1534 @@ +[ + { + "type": "text", + "text": "Make-An-Animation: Large-Scale Text-conditional 3D Human Motion Generation", + "text_level": 1, + "bbox": [ + 181, + 130, + 789, + 174 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Samaneh Azadi", + "bbox": [ + 127, + 203, + 256, + 220 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Akbar Shah", + "bbox": [ + 299, + 203, + 395, + 220 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Thomas Hayes Meta AI", + "bbox": [ + 437, + 203, + 557, + 237 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Devi Parikh", + "bbox": [ + 599, + 203, + 697, + 220 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Sonal Gupta", + "bbox": [ + 738, + 203, + 841, + 222 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 273, + 313, + 289 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Text-guided human motion generation has drawn significant interest because of its impactful applications spanning animation and robotics. Recently, application of diffusion models for motion generation has enabled improvements in the quality of generated motions. However, existing approaches are limited by their reliance on relatively small-scale motion capture data, leading to poor performance on more diverse, in-the-wild prompts. In this paper, we introduce Make-An-Animation, a text-conditioned human motion generation model which learns more diverse poses and prompts from large-scale image-text datasets, enabling significant improvement in performance over prior works. Make-An-Animation is trained in two stages. First, we train on a curated large-scale dataset of (text, static pseudo-pose) pairs extracted from image-text datasets. Second, we fine-tune on motion capture data, adding additional layers to model the temporal dimension. Unlike prior diffusion models for motion generation, Make-An-Animation uses a U-Net architecture similar to recent text-to-video generation models. Human evaluation of motion realism and alignment with input text shows that our model reaches state-of-the-art performance on text-to-motion generation. Generated samples can be viewed at https://azadis.github.io/make-an-animation.", + "bbox": [ + 76, + 305, + 473, + 667 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 693, + 209, + 709 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "As the world shifts towards virtual spaces, and as embodied agents become more capable, it will be increasingly important to be able to generate plausible human motion. Speech or text are perhaps the most natural ways to prompt generative models, which is one reason behind the explosion in text-to-x generation research. Human motion generation from text has diverse applications both in virtual and real worlds. For instance, it enables control of robots with speech, faster video game development, creation of special effects featuring humans, as well as novel metaverse user-interaction modes whereby users can control the actions of their or others' avatars via voice or text.", + "bbox": [ + 75, + 719, + 470, + 900 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/3317ca5bee291c7b6c3d5d776e32d9bf3a832d6b06166be90aece8cfd0b7dfe4.jpg", + "image_caption": [ + "A person is chopping down a tree with an axe." + ], + "image_footnote": [], + "bbox": [ + 501, + 300, + 901, + 426 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/57caa933c66f5502d33fed499cda001669effa970a7266ab9769aa6b2dc2a21b.jpg", + "image_caption": [ + "A person is ice skating.", + "Figure 1. Samples generated by Make-An-Animation for text conditional motion generation. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. In the top image, for a better visualization, frames are distributed horizontally." + ], + "image_footnote": [], + "bbox": [ + 501, + 459, + 901, + 597 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Text-conditioned human motion generation is challenging for a number of reasons. Firstly, there exists a huge diversity of human motions and text descriptions which describe those motions (i.e., the task is many-to-many distribution matching). Secondly, because motion capture data is expensive to acquire, human motion datasets are limited in scale and diversity.", + "bbox": [ + 496, + 731, + 893, + 837 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Recently, text-to-motion generation has seen rapid improvements in the quality and diversity of poses generated. In particular, diffusion models, which have yielded impressive results in text-conditioned image and video genera", + "bbox": [ + 496, + 839, + 893, + 900 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "15039", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "tion, have proven effective in generating human body poses [35, 16, 38]. However, these models struggle with in-the-wild prompts that are outside of the distribution of motion capture data.", + "bbox": [ + 75, + 90, + 468, + 151 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To address these shortcomings, we present Make-An-Animation, a text-conditioned human motion generation model which learns to map diverse human poses to natural language descriptions through in-the-wild image-text datasets and significantly improves on prior state-of-the-art models which only rely on motion capture data.", + "bbox": [ + 75, + 151, + 468, + 242 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Core to our approach is a large-scale dataset of human poses extracted from image-text datasets. Our key observation is that we should not be limited to learning human motion from motion capture data when we have access to large-scale in-the-wild video and images of human poses. So, to address the limited scale and diversity of motion capture datasets, we extract a large-scale Text Pseudo-Pose (TPP) dataset from image-text datasets filtered for images containing humans. This TPP dataset contains 35M (text, static pose) pairs.", + "bbox": [ + 75, + 242, + 467, + 393 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Make-An-Animation is trained in two stages: (1) We train a text-conditioned static 3D pose generation diffusion model on the TPP dataset. In this stage, Make-An-Animation learns the distribution of human poses and their alignment with text. (2) Then, we extend the pre-trained diffusion model to motion generation via the addition of temporal convolution and attention layers which model the new temporal dimension and train on widely-used motion capture data. In this second stage, the model learns motion, i.e., how to connect poses in a temporally coherent manner. Crucially, it does not have to re-learn the distribution of feasible poses or their alignment with text.", + "bbox": [ + 75, + 393, + 467, + 574 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The Make-An-Animation architecture is a U-Net, similar to recent text-to-video diffusion models. We condition the U-Net on text representations extracted from a language model trained on large-scale language data. We represent human motion as a sequence of 3D SMPL body parameters, with a 6D continuous SMPL representation for 21 body joints and the root orient. We additionally represent the global position per frame via a 3D vector indicating the position in each of the $x, y, z$ dimensions.", + "bbox": [ + 75, + 575, + 467, + 710 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Through human evaluation on a collected set of 400 diverse text prompts, we demonstrate that our method outperforms prior works in terms of generated pose realism and text alignment.", + "bbox": [ + 75, + 710, + 467, + 771 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To summarize, our main contributions are:", + "bbox": [ + 96, + 772, + 379, + 786 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We present Make-An-Animation - a text-conditioned human motion generation model which improves on prior state-of-the-art models, especially on diverse, in-the-wild text prompts.", + "- We show, for the first time, how to leverage large-scale image datasets to learn in-the-wild human poses" + ], + "bbox": [ + 94, + 797, + 467, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "for generation. We show through ablations that pretraining on our collected Text Pseudo-Pose dataset significantly improves the generalization to prompts outside the distribution of widely-used motion capture datasets while showing a comparable performance on the mocap test set.", + "bbox": [ + 529, + 90, + 890, + 181 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "- We present a U-Net architecture for human motion generation which leverages a language model pretrained on large-scale language data and naturally extends a static text-to-pose generation diffusion model to motion generation via the addition of temporal convolution and attention layers.", + "bbox": [ + 517, + 190, + 890, + 281 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Works", + "text_level": 1, + "bbox": [ + 500, + 301, + 648, + 316 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Human pose and motion generation Prior works in human pose and motion synthesis have explored generative models either unconditionally [36, 40, 25], or conditioned on various input signals such as a prior motion [20, 29], an action class [11, 23, 5], or music [17, 18].", + "bbox": [ + 498, + 325, + 890, + 402 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Using text descriptions as a guidance in pose and motion synthesis has been a more recent research direction where many existing works use 2D keypoints as pose representations. [41] selects a base pose from 8 clusters based on an input text fed to a GAN model to generate a human image. [39] uses a GAN to generate a set of heatmaps for body keypoints conditioned on the text input. [28] proposes a coarse-to-fine approach where a refinement stage is introduced on top of the initial coarse estimate of the keypoints heatmaps. Different from the above methods, [3] uses SMPL to represent a 3D body pose, generated by an LSTM GAN from a text input.", + "bbox": [ + 496, + 402, + 890, + 582 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Many existing works approach text-to-motion by learning to align text and pose or motion embeddings in the feature space. JL2P [1] proposes to learn the joint embedding of text and pose using an autoencoder with curriculum learning. [7] proposes a two-stream model to encode upper and lower body motions separately. AvatarCLIP [15] uses a pre-trained VPoser model to generate candidate poses, which are then used to optimize a motion VAE. Motion-CLIP [34] trains an auto-encoder while simultaneously reconstructing motion and aligning the motion manifold with CLIP's latent space. TEMOS [24] trains a joint latent space through separate text and motion transformer encoders, allowing non-deterministic motion sampling. T2M [9] also uses a VAE model, but encodes motion as snippets and introduces an extra sampling for motion length conditioned on the input text.", + "bbox": [ + 496, + 584, + 890, + 824 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Leveraging recent advancements in diffusion models, Motion Diffusion Model (MDM) [35], MotionDiffuse [38], and FLAME [16] adopt a diffusion process from text to motion with a transformer, which can significantly improve the diversity of synthesized samples. MDM and MotionDiffuse", + "bbox": [ + 496, + 825, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "15040", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/1d8f6f235d9b2aa47cf74a16dc92d1ce491df36c91bf2b01d8d4a8ebf03bd5ca.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 86, + 88, + 385, + 383 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/14df4dd0c11dcd1907f5156daa839d7796466c23136fedd1b4f28e772206869a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 401, + 88, + 632, + 378 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/f0d48255d8e997126ec0cb6c968e7aae51da4d1d40c6e1ff5beefe480b04ea24.jpg", + "image_caption": [ + "Figure 2. Make-An-Animation Model Architecture. Our diffusion model is built on a U-Net architecture inspired by recent image and video generation models. The U-Net consists of a sequence of Residual Blocks with 1x1 2D-convolution layers and Attention Blocks with cross-attention on textual information. To model the temporal dimension, we add 1D temporal convolution layers after each 1x1 2D-convolution, as well as temporal attention layers after each cross-attention layer. These temporal layers (greyed out in the figure) are only added in the motion fine-tuning stage." + ], + "image_footnote": [], + "bbox": [ + 643, + 89, + 888, + 395 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "are trained on HumanML3D [9] which partially limits their choice of representation to stick figures for text-to-motion generation, while our curated large-scale dataset provides millions of SMPL pose labels. MDM supports converting poses from stick figures to SMPL bodies only through an optimization SIMPLIFY-X[22] procedure that often results in unrealistic body poses.", + "bbox": [ + 75, + 493, + 470, + 602 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Diffusion generative models Diffusion models are a class a generative model based on the thermodynamic stochastic diffusion process. In the forward diffusion process, a sample is drawn from the data distribution and is gradually noised by a diffusion process. A neural network learns the reverse process to gradually denoise the sample.", + "bbox": [ + 75, + 627, + 468, + 718 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Diffusion models have recently enabled rapid advancements in image generation. [13] first demonstrated diffusion models for unconditional image generation. In comparison to GANs [8] and VAEs, diffusion models have shown superior training stability, avoid mode dropout, and yield stronger performance. Adapting diffusion models for conditional generation, [6] introduced classifier-guided diffusion. More recently, classifier free guidance [14] has been introduced to enable conditioning without the need for a separate classifier. Imagen [30] showed that conditioning on text embeddings extracted from a pre-trained language model enhanced text alignment, and that perfor", + "bbox": [ + 75, + 719, + 470, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "mance improved with text encoder size. Our U-Net architecture shares similarities withImagen. Namely, Make-An-Animation uses the same text encoder, T5-XXL [26], and a similar U-Net architecture. Other improvements have been suggested to improve training stability and performance, such as learning the reverse diffusion variances [21] and v-parameterization [31]. Our method leverages both of these improvements.", + "bbox": [ + 496, + 493, + 893, + 616 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Text-to-3D Human Motion Generation", + "text_level": 1, + "bbox": [ + 498, + 626, + 848, + 642 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Dataset", + "text_level": 1, + "bbox": [ + 500, + 650, + 596, + 666 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3D Human motion datasets. We use the AMASS dataset of 3D human motions [19] and its textual annotations from the HumanML3D dataset [10]. We borrow the original SMPL annotations from AMASS instead of the processed data from HumanML3D dataset since (1) we found their motion representation contains redundant information, and (2) an extra optimization step would be required to convert their motion representations to the original SMPL format resulting in a degradation in the quality and speed of motion generation in the SMPL format. Similar to HumanML3D, we double the size of the dataset by mirroring the motions and editing the textual description accordingly, resulting in 26850 motion examples in the training set. Additionally, we benefit from the GTA-Human dataset [4] built from an open-world action game providing SMPL annotations over", + "bbox": [ + 496, + 672, + 893, + 902 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "15041", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/4410f0feb8eabebd5f78beed0648e0da6755be18aa084f368bd1773f3420905a.jpg", + "image_caption": [ + "Figure 3. A few examples from our collected TPP dataset." + ], + "image_footnote": [], + "bbox": [ + 83, + 90, + 178, + 170 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/dfdfb1c0f5e6d3f07251f6f6cf241937d78912177e753452a9d88f383b65d1fc.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 184, + 90, + 272, + 169 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/703290c9fd07ed1eaaed5db90d3dab7ae757ced27c0f9f76c8adf5974b75afb3.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 284, + 95, + 372, + 169 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/cae0220e04cd165447855d36513db42a2945aa190626041302df17b2831754a4.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 379, + 95, + 475, + 169 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "laid on the virtual humans for 20000 motion samples. This dataset does not have any textual annotation, thus we use it for an unconditional training of our model simultaneous to its text-conditional training.", + "bbox": [ + 75, + 215, + 468, + 275 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Since the existing mocap datasets are limited in the number of samples and their diversity, we also collected a large-scale dataset of in-the-wild human poses from image datasets as follows.", + "bbox": [ + 75, + 276, + 468, + 335 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Large-scale Text Pseudo-Pose (TPP) dataset. Similar to [2], we have collected a dataset containing 35M pairs of human poses and their text descriptions from a few large-scale image-text datasets. We processed all images by running Detectron2 keypoint detector to find images with a single human, then extracted their 3D pseudo-pose SMPL annotations using a pre-trained PyMAF-X model [37]. We used the publicly available captions without any processing. This large-scale data overcomes the limitations of the existing mocap datasets by providing a wide variety of human poses and a huge number of (text, 3D pose) sample pairs despite being noisy. We do not extract any face or hand expressions from the aforementioned datasets. A few examples of the (pseudo-pose, text) pairs are shown in Figure 3.", + "bbox": [ + 75, + 354, + 468, + 580 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Diffusion Models Background", + "text_level": 1, + "bbox": [ + 76, + 590, + 344, + 606 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Diffusion models are a class of generative model that convert Gaussian noise into samples from a learned distribution by iterative denoising. The forward process is a Gaussian noisin processing following a Markove chain, $\\{x_{t}\\}_{t = 0}^{T}$ where $x_0$ is drawn from the data distribution, in our case a set of 3D SMPL body poses. We can express the forward process as $q(x_{t}|x_{t - 1}) = \\mathcal{N}(\\sqrt{\\alpha_{t}} x_{t - 1},(1 - \\alpha_{t})\\mathbf{I})$ where $\\alpha_{t}\\in (0,1)$ . As is standard in training diffusion models, we learn to reverse the forward process by minimizing a noise-prediction loss [13]:", + "bbox": [ + 75, + 613, + 468, + 765 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {s i m p l e}} = \\mathbb {E} _ {\\epsilon \\sim \\mathcal {N} (0, \\mathbf {I}), t \\sim U [ 1, T ]} \\left[ \\| \\epsilon_ {t} - \\epsilon_ {\\theta} (x _ {t}, c, t) \\| _ {2} ^ {2} \\right] \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 94, + 773, + 468, + 800 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $c$ is the optional conditioning for the diffusion model, which in our cases are text descriptions.", + "bbox": [ + 75, + 809, + 467, + 840 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In addition to this simple loss, we follow [21, 27] and optimize the hybrid loss, which also uses a loss $L_{vlb}$ that adds a constraint on the estimated variational lower bound (VLB). The $L_{vlb}$ term is applied the same way as in [21].", + "bbox": [ + 75, + 839, + 468, + 901 + ], + "page_idx": 3 + }, + { + "type": "table", + "img_path": "images/6523353753481331ddf8199b00fe3cdd2559ff1912157f02069458f57b777df9.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodR-Precision ↑FID ↓Diversity ↑
Real0.797±0.0020.002±0.0029.5±0.65
J2LP[[1]]0.486±.00211.02±.0467.676±.058
MDM[[35]]0.611±.0070.544±.0449.559±.086
T2M[[9]]0.740±.0031.067±.0029.188±.002
MAA0.6755±.0020.7740±0.0078.23±0.064
", + "bbox": [ + 517, + 88, + 875, + 204 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Table 1. Quantitative results on the HumanML3D test set. We run our evaluation 20 times and $\\pm$ indicates the $95\\%$ confidence interval.", + "bbox": [ + 498, + 205, + 890, + 247 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We follow [12, 31] and parameterize our models using $v$ -parameterization ( $v_{t} = \\alpha_{t}\\epsilon - \\sigma_{t}x$ ) rather than predicting $\\epsilon$ or $x$ .", + "bbox": [ + 498, + 258, + 890, + 304 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Make-An-Animation", + "text_level": 1, + "bbox": [ + 500, + 315, + 696, + 330 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We represent an avatar body pose, $P$ , via 3D SMPL body parameters and an avatar motion as a sequence of body poses for $N$ frames, $[P_1, P_2, \\dots, P_N]$ . We use 6D continuous SMPL representation for 21 body joints and the root orient. We additionally represent the global position per frame via a 3D vector indicating the avatar's position in each of the $x, y, z$ dimensions, resulting in each $P_i \\in \\mathbb{R}^{135}$ . Make-An-Animation is built from three major components: (1) a pre-trained language model trained on a large-scale language data (T5-XXL [26]), (2) a text-to-3D diffusion based pose generation model trained on our collected TPP dataset, and (3) a set of temporal convolution and attention layers extending the static pose generation model to the temporal dimension for motion generation and capturing the dependencies between the frames.", + "bbox": [ + 496, + 339, + 890, + 565 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We follow [12] and use v-prediction parameterization $(v_{t} = \\alpha_{t}\\epsilon -\\sigma_{t}x)$ to train our pose and motion diffusion models for numerical stability. Our denoising model in the above U-Net architecture operates on all motion frames at the same time resulting in a higher temporal coherence in the generated motions compared to the autoregressive frameworks [35] and does not require any specific loss on the motion velocity for a smooth motion synthesis. We also benefit from classifier free guidance [14] at inference by conditioning our model on a null text during training for $10\\%$ of the time.", + "bbox": [ + 498, + 566, + 890, + 732 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3.1 Text-to-3D Pose Generation", + "text_level": 1, + "bbox": [ + 500, + 753, + 746, + 768 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We train a U-Net based diffusion model to generate 3D SMPL pose parameters conditioning on text embeddings from a large frozen language model [26]. Inspired by the image and video generation models [32], we reshape the pose inputs to $B \\times C \\times 1 \\times 1$ with $B$ and $C$ indicating batch size and channel dimension of 135, respectively. Our U-Net model is built from a sequence of (1) Residual blocks with 1x1 2D-convolution layers conditioned on the diffu", + "bbox": [ + 496, + 779, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "15042", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/9f38604501a931b869b823c882a6b8880d19bf2531644212a9f1d40b01b75c3e.jpg", + "image_caption": [ + "(a) Which motion corresponds better with the textual description?" + ], + "image_footnote": [], + "bbox": [ + 101, + 114, + 449, + 253 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/7c1d16a5fe0d6266594b338413ad1fc8fd92871303265f7e08511d782cf62e6a.jpg", + "image_caption": [ + "(b) Which motion is more realistic?", + "Figure 4. Human Evaluation. Here we compare each baseline against our model, MAA, in terms of text alignment and motion realism. The results are reported as the percentage of the majority vote raters that preferred our method to each baseline on our curated 400 prompts set." + ], + "image_footnote": [], + "bbox": [ + 509, + 116, + 844, + 253 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/817dea198838115243d293082e25f811218002fb5459034c461035860edba322.jpg", + "image_caption": [ + "Figure 5. Ablation Study. Here we compare each ablated model against our model, MAA, in terms text alignment and motion realism. The results are reported as the percentage of the majority vote raters that preferred our method to each baseline on our curated 400 prompts set." + ], + "image_footnote": [], + "bbox": [ + 94, + 361, + 439, + 498 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "sion time-step embedding and text embedding, and (2) Attention Blocks attending to the textual information and the diffusion time-step. We train this network on our large-scale TPP dataset where we set translation parameters to zero in all training examples, i.e., human at the center of the scene.", + "bbox": [ + 75, + 599, + 468, + 676 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.3.2 Temporal and Attention Layers", + "text_level": 1, + "bbox": [ + 76, + 695, + 352, + 710 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In order to expand the aforementioned pose generation model to learn the temporal dimension for motion generation, we modify the convolutional and attention layers of the U-Net as follows.", + "bbox": [ + 75, + 719, + 468, + 777 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We reshape the input motion sequence to a tensor of shape $B \\times C \\times N \\times 1 \\times 1$ , where $C$ is the length of the pose representation and $N$ is the number of frames. Inspired by [32, 12], we stack a 1D temporal convolution layer following each 1x1 2D-convolution. This allows us to train the new 1D temporal layers from scratch while loading the pre-trained convolution weights from the pose generation model. We set the kernel size of these temporal convolution", + "bbox": [ + 75, + 780, + 470, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "layers to 3 opposed to the unit kernel size of the 2D convolutions. We apply a similar dimension decomposition strategy to the attention layers, where we stack a newly initialized temporal attention layer to each pre-trained attention block from the pose generation network. For the temporal attention layers we utilize a Rotary Position Embedding [33].", + "bbox": [ + 496, + 349, + 890, + 441 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 500, + 452, + 633, + 469 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We compare the performance of our motion generation model with the existing state-of-the-art text-to-human-motion generation models through human evaluation on 400 crowd-sourced prompts and automatic metrics on the HumanML3D test set.", + "bbox": [ + 496, + 478, + 890, + 551 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Automatic Metrics", + "text_level": 1, + "bbox": [ + 500, + 560, + 679, + 574 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We perform an automatic evaluation on the HumanML3D test set in terms of Fréchet Distance (FID), R-Precision and Diversity scores. FID measures both diversity and quality of the samples comparing its distribution with the ground truth test set while R-Precision measures faithfulness between each generated motion and its input prompt. Diversity measures the variance of the generated motions across all descriptions. To compute the above scores, a motion encoder was jointly trained with a text encoder via a contrastive loss by [9]. We use the same encoder to extract text and motion embeddings. Since this model has been trained and optimized on the 263-dimensional pose representation vector, we transform both the ground-truth SMPL data and our generated samples similarly following the transformations provided by [11] before computing the above metrics. We upsample our generations to 196 frames and keep that fixed for the ground truth samples and our outputs while computing the above metrics. Opposed to our baselines, we have not optimized our model on the 263-dimensional motion representation, but achieve a comparable performance in all metrics as reported in Table 1.", + "bbox": [ + 496, + 583, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "15043", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Human Evaluation", + "text_level": 1, + "bbox": [ + 76, + 90, + 261, + 104 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To evaluate the generalization ability of our model in synthesizing more challenging human poses and motions, we collected an evaluation set from Amazon Mechanical Turk (AMT) that consists of 400 prompts. We asked annotators for prompts that described an action along with some context of the scene. We filtered out prompts based on ethical concerns to remove any references to children or NSFW content. These prompts were selected without generating any poses or images for them, and were kept fixed for all of our evaluations. This test set is released here1. We generated animated poses from all models with no translation to measure the correctness and quality of the body pose and motion. We show raters a text description and the corresponding rendered avatars from two models and ask them which output better matches the input text. For each comparison, we use the majority vote from 7 different annotators on 400 prompts as the final result, reported in Figure 4. This study confirms the superiority of our model and the impact of our large-scale TPP dataset in human motion generation and overcoming the limitations of the mocap datasets. A few motion samples generated by our model are shown in Figure 8 and more are included on our webpage1.", + "bbox": [ + 75, + 114, + 473, + 448 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Ablation Studies", + "text_level": 1, + "bbox": [ + 76, + 458, + 243, + 472 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To disentangle and study the impact of our U-Net architecture versus the impact on our TPP dataset on our results, we implemented and trained an alternative diffusion model as a decoder-only transformer with a causal attention mask to generate 3D pose representations from text. This model operates on a sequence of tokenized captions and their text embeddings, the diffusion time-step embedding, the noised body pose and root orient representations, and two final pose and orientation queries to predict the unnoised pose and root orientation, respectively. We pre-trained this model on our TPP dataset, then expanded the model for motion synthesis via adding three additional tokens per frame for pose, root orient, and translation paramters. We trained this model on the mocap datasets described in Sec 3.1 and compared its performance with our U-Net model via Amazon Mechanical Turk. As a result, $58\\%$ of the raters preferred the generations from our U-Net architecture. This experiment confirms the superiority of the U-Net model versus its auto-regressive alternatives. We also ablated the impact of temporal attention modules on the final quality of the samples resulting in $54\\%$ of the users preferring samples from a U-Net with temporal attention.", + "bbox": [ + 75, + 481, + 472, + 813 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Training with the GTA data unconditionally made the convergence of the model faster although it didn't impact the samples' quality after convergence.", + "bbox": [ + 75, + 814, + 470, + 859 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Additionally, we experimented with training our U-Net", + "bbox": [ + 96, + 859, + 470, + 876 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/99d8ae57a92f5c1b873b17f8455473633da3c82464e90b08ee1bce94f8b55f27.jpg", + "image_caption": [ + "A person is playing football in playground" + ], + "image_footnote": [], + "bbox": [ + 584, + 98, + 861, + 202 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/770a6c7a92c302d46258861724fc1dbada72027158d24c0c39cf24683b5f9c21.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 584, + 207, + 861, + 315 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/5550d41fb7701fde2559aaee472deda3fa78cda78910aef9649ec4e0fda5bfeb.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 584, + 316, + 861, + 420 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/b147549a7d3b0619e62349fce672b863c3c8086476f733cf4d2d4bf1f3e95ee9.jpg", + "image_caption": [ + "A person dancing in the street" + ], + "image_footnote": [], + "bbox": [ + 584, + 455, + 861, + 559 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/e6d1195e1ea003346f3a827ff592fa77cecdffbceb1559cf6afe573801f29ea8.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 584, + 565, + 861, + 666 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/b8765ec569532be7bdfd53cbc8ed37a49db2993571219f219a488acca0877fea.jpg", + "image_caption": [ + "Figure 6. Diverse samples generated by Make-An-Animation for text conditional motion generation. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. For a better visualization, frames are down-sampled along the temporal dimension and distributed horizontally." + ], + "image_footnote": [], + "bbox": [ + 584, + 667, + 861, + 768 + ], + "page_idx": 5 + }, + { + "type": "page_footnote", + "text": "1 https://azadis.github.io/make-an-animation", + "bbox": [ + 94, + 886, + 328, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "15044", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/ca571b6c0bd8a486c30d92d6e17e4ab78f20054460a9aaac50b42d15fa1eaeff.jpg", + "image_caption": [ + "MAA Generations", + "A person wrestles a bear in the forest" + ], + "image_footnote": [], + "bbox": [ + 80, + 113, + 467, + 258 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/84f7f6cd8a5319c361eed8fe9ffd976008a42a8d528300270e0e335e00be6b35.jpg", + "image_caption": [ + "Nearest Neighbour Example", + "a person puts both arms into the air" + ], + "image_footnote": [], + "bbox": [ + 503, + 114, + 890, + 258 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/b421531488792713fad60a3b93fbaff18d581ca8fe2f06fadf104a235358bebc.jpg", + "image_caption": [ + "A person is practicing the flute" + ], + "image_footnote": [], + "bbox": [ + 78, + 292, + 467, + 434 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/d981404c575242b5fd968461147e9fcfaf3b16f747c2d4f2082bf32689ca74b7.jpg", + "image_caption": [ + "a person clapping with his hands" + ], + "image_footnote": [], + "bbox": [ + 503, + 292, + 890, + 435 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/ecfe3bf181726948b0aa5d32657a80aa31ab14ac3ce87253b3ff91a8b0575518.jpg", + "image_caption": [ + "A person is sawing a branch off of a tree", + "Figure 7. Left: samples generated by Make-An-Animation for text conditional motion generation. Right: The nearest neighbor example for each of the generated samples found from the mocap training set based on motion and text clip similarity scores. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. For a better visualization, frames are distributed horizontally." + ], + "image_footnote": [], + "bbox": [ + 78, + 463, + 467, + 604 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/b9f83de2b62046177c659e6d7cc6d30e46f2576fe90dd30f6d2b196df5bf45db.jpg", + "image_caption": [ + "a man raises his hands to his chest, claps them together, then lowers them back to his sides" + ], + "image_footnote": [], + "bbox": [ + 503, + 463, + 890, + 604 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "model on the mocap training set from scratch and without pre-training. However, we observed stability and convergence issues in this setting even with various learning rates and warming up updates. The pre-training stage on the large-scale dataset was therefore a stable solution resulting in high quality motion samples in the end. All ablation results are summarized in Figure 5.", + "bbox": [ + 75, + 717, + 468, + 823 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4. Qualitative Studies", + "text_level": 1, + "bbox": [ + 76, + 832, + 259, + 848 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In Figure 7, we visualize the generalization capability of our model in synthesizing novel motions. We investigate the existence of similar prompts or motions in the train", + "bbox": [ + 75, + 854, + 468, + 900 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "ing data for each synthesized motion via a nearest neighbor search. We extract the motion embedding and text embedding for each sample in our test set of prompts as well as our mocap training data using a pre-trained motionCLIP model [34, 16] that has learned a joint motion and language embedding space. For each synthesized motion, we find the top 6 motions and prompts from the training data with the highest cosine similarity scores. As shown in the figure, our model has generalized to new motions that did not exist in the training data. In addition, Figure 6 illustrates multiple diverse motions generated by our model for different text prompt.", + "bbox": [ + 496, + 717, + 890, + 898 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "15045", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/bfa30e679e5c72d388a9e401992ec85602fa91aafd101aea0de0bfbd322f6648.jpg", + "image_caption": [ + "A person is doing a handstand on a cactus" + ], + "image_footnote": [], + "bbox": [ + 80, + 95, + 459, + 247 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/ba5d9b87d012d84495342e7dfc2e0c1a4705f2f8fe094567fea5724c6828f1af.jpg", + "image_caption": [ + "A person kicks a soccer ball" + ], + "image_footnote": [], + "bbox": [ + 513, + 125, + 890, + 247 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/82f978aeb2350eb6eea71114941428390649b20eb978ac7c916327d4436546c5.jpg", + "image_caption": [ + "A person is rowing a small dingy in a river" + ], + "image_footnote": [], + "bbox": [ + 80, + 276, + 455, + 414 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/f04008afad21d8211f0c71bef053c4cacdf8e04167f8b9594ebc4f05b2dc14d8.jpg", + "image_caption": [ + "A person is playing tennis at the Recreation Center" + ], + "image_footnote": [], + "bbox": [ + 513, + 267, + 890, + 415 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/5dc2504192f488274b3f3e703945552b165baf030730221d0a6297a57d25f19a.jpg", + "image_caption": [ + "A volleyball player bumps a ball up" + ], + "image_footnote": [], + "bbox": [ + 80, + 441, + 455, + 580 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/4d044153d9b28e995fec65730adaa4a28808b80184f62ae4a8ce2ebfc54b7270.jpg", + "image_caption": [ + "A photographer is looking through the camera" + ], + "image_footnote": [], + "bbox": [ + 513, + 444, + 890, + 580 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/f4e92455eb3fbdd47409027ff835b39d5151e7be18247c48047b98e0b7c2d3ef.jpg", + "image_caption": [ + "A person is shoveling the driveway after a blizzard" + ], + "image_footnote": [], + "bbox": [ + 80, + 604, + 450, + 737 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/5c21ffc224a3bc82285b3aae5aff2d43ff2727d36f32df654872bfcf8c4162e9.jpg", + "image_caption": [ + "A person is sitting down on the ground", + "Figure 8. Samples generated by Make-An-Animation for text conditional motion generation. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. For a better visualization, frames are distributed horizontally." + ], + "image_footnote": [], + "bbox": [ + 513, + 617, + 890, + 737 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 816, + 194, + 832 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Current text-to-motion models are hindered by relatively small-scale motion capture datasets, as evident by their poor performance on more diverse, in-the-wild prompts.", + "bbox": [ + 75, + 854, + 468, + 902 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Motivated by this shortcoming, we present Make-An-Animation, a human motion generation model trained on a collection of large-scale static pseudo-pose and motion capture data. As we demonstrate through our ablations and human studies comparing to prior works, pre-training on the", + "bbox": [ + 498, + 818, + 893, + 895 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "15046", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "large-scale TPP dataset significantly improves performance on captions outside of the distribution of motion capture data. Furthermore, our novel U-Net architecture enables a seamless transition between static pose pre-training and dynamic pose (i.e., motion) fine-tuning. Altogether, this work paves the way to leverage large-scale image and video datasets for learning generation of human 3D pose parameters.", + "bbox": [ + 75, + 90, + 472, + 210 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 501, + 90, + 596, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Chaitanya Ahuja and Louis-Philippe Morency. Language2pose: Natural language grounded pose forecasting. IEEE International Conference on 3D Vision (3DV), pages 719-728, 2019.", + "[2] Samaneh Azadi, Thomas Hayes, Akbar Shah, Guan Pang, Devi Parikh, and Sonal Gupta. Text-conditional contextualized avatars for zero-shot personalization. arXiv preprint arXiv:2304.07410, 2023.", + "[3] Rania Briq, Pratika Kochar, and Juergen Gall. Towards better adversarial synthesis of human images from text. arXiv preprint arXiv:2107.01869, 2021.", + "[4] Zhongang Cai, Mingyuan Zhang, Jiawei Ren, Chen Wei, Daxuan Ren, Zhengyu Lin, Haiyu Zhao, Lei Yang, and Zwei Liu. Playing for 3d human recovery. arXiv preprint arXiv:2110.07588, 2021.", + "[5] Pablo Cervantes, Yusuke Sekikawa, Ikuro Sato, and Koichi Shinoda. Implicit neural representations for variable length human motion generation. European Conference on Computer Vision (ECCV), 2022.", + "[6] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Advances in Neural Information Processing Systems (NeurIPS), 34, 2021.", + "[7] Anindita Ghosh, Noshaba Cheema, Cennet Oguz, Christian Theobalt, and Philipp Slusallek. Synthesis of compositional animations from textual descriptions. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 1396-1406, October 2021.", + "[8] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In Advances in Neural Information Processing Systems, 2014.", + "[9] Chuan Guo, Shihao Zou, Xinxin Zuo, Sen Wang, Wei Ji, Xingyu Li, and Li Cheng. Generating diverse and natural 3d human motions from text. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 5152-5161, June 2022.", + "[10] Chuan Guo, Shihao Zou, Xinxin Zuo, Sen Wang, Wei Ji, Xingyu Li, and Li Cheng. Generating diverse and natural 3d human motions from text. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 5152-5161, June 2022.", + "[11] Chuan Guo, Xinxin Zuo, Sen Wang, Shihao Zou, Qingyao Sun, Annan Deng, Minglun Gong, and Li Cheng. Action2motion: Conditioned generation of 3d human motions. Proceedings of the 28th ACM International Conference on Multimedia, pages 2021-2029, 2020.", + "[12] Jonathan Ho, William Chan, Chitwan Saharia, Jay Whang, Ruiqi Gao, Alexey Gritsenko, Diederik P Kingma, Ben Poole, Mohammad Norouzi, David J Fleet, et al. Imagen video: High definition video generation with diffusion models. arXiv preprint arXiv:2210.02303, 2022.", + "[13] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Advances in Neural Information Processing Systems (NeurIPS), 33, 2020.", + "[14] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. arXiv preprint arXiv:2207.12598, 2022." + ], + "bbox": [ + 501, + 114, + 893, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "15047", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[15] Fangzhou Hong, Mingyuan Zhang, Liang Pan, Zhongang Cai, Lei Yang, and Ziwei Liu. Avatarclip: Zero-shot text-driven generation and animation of 3d avatars. ACM Transactions on Graphics (TOG), 41(4):1-19, 2022.", + "[16] Jihoon Kim, Jiseob Kim, and Sungjoon Choi. Flame: Freeform language-based motion synthesis & editing. arXiv preprint arXiv:2209.00349, 2022.", + "[17] Hsin-Ying Lee, Xiaodong Yang, Ming-Yu Liu, Ting-Chun Wang, Yu-Ding Lu, Ming-Hsuan Yang, and Jan Kautz. Dancing to music. Advances in Neural Information Processing Systems (NeurIPS), 32, 2019.", + "[18] Ruilong Li, Shan Yang, David A. Ross, and Angjoo Kanazawa. Ai choreographer: Music conditioned 3d dance generation with aist++. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), 2021.", + "[19] Naureen Mahmood, Nima Ghorbani, Nikolaus F. Troje, Gerard Pons-Moll, and Michael J. Black. AMASS: Archive of motion capture as surface shapes. In International Conference on Computer Vision, pages 5442-5451, Oct. 2019.", + "[20] Julieta Martinez, Michael J. Black, and Javier Romero. On human motion prediction using recurrent neural networks. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2017.", + "[21] Alexander Quinn Nichol and Prafulla Dhariwal. Improved denoising diffusion probabilistic models. In International Conference on Machine Learning, pages 8162-8171. PMLR, 2021.", + "[22] Georgios Pavlakos, Vasileios Choutas, Nima Ghorbani, Timo Bolkart, Ahmed A. A. Osman, Dimitrios Tzionas, and Michael J. Black. Expressive body capture: 3d hands, face, and body from a single image. In Conference on Computer Vision and Pattern Recognition (CVPR), 2019.", + "[23] Mathis Petrovich, Michael J. Black, and Gül Varol. Action-conditioned 3D human motion synthesis with transformer VAE. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 10985-10995, October 2021.", + "[24] Mathis Petrovich, Michael J. Black, and Gül Varol. Temos: Generating diverse human motions from textual descriptions. European Conference on Computer Vision (ECCV), 2022.", + "[25] Sigal Raab, Inbal Leibovitch, Peizhuo Li, Kfir Aberman, Olga Sorkine-Hornung, and Daniel Cohen-Or. Modi: Unconditional motion synthesis from diverse data. arXiv preprint arXiv:2206.08010, 2022.", + "[26] Colin Raffel, Noam Shazeer, Adam Roberts, Katherine Lee, Sharan Narang, Michael Matena, Yanqi Zhou, Wei Li, and Peter J. Liu. Exploring the limits of transfer learning with a unified text-to-text transformer. JMLR, 2020.", + "[27] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022.", + "[28] Prasun Roy, Subhankar Ghosh, Saumik Bhattacharya, Umapada Pal, and Michael Blumenstein. Tips: Text-induced pose synthesis. European Conference on Computer Vision (ECCV), 2022." + ], + "bbox": [ + 78, + 90, + 468, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[29] Alejandro Hernandez Ruiz, Juergen Gall, and Francesc Moreno-Noguer. Human motion prediction via spatiotemporal inpainting. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), 2019.", + "[30] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S. Sara Mahdavi, Rapha Gontijo Lopes, Tim Salimans, Jonathan Ho, David J Fleet, and Mohammad Norouzi. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022.", + "[31] T. Salimans and J Ho. Progressive distillation for fast sampling of diffusion models. International Conference on Learning Representations, 2022.", + "[32] Uriel Singer, Adam Polyak, Thomas Hayes, Xi Yin, Jie An, Songyang Zhang, Qiyuan Hu, Harry Yang, Oron Ashual, Oran Gafni, et al. Make-a-video: Text-to-video generation without text-video data. arXiv preprint arXiv:2209.14792, 2022.", + "[33] Jianlin Su, Yu Lu, Shengfeng Pan, Ahmed Murtadha, Bo Wen, and Yunfeng Liu. Roformer: Enhanced transformer with rotary position embedding. arXiv preprint arXiv:2104.09864, 2021.", + "[34] Guy Tevet, Brian Gordon, Amir Hertz, Amit H. Bermano, and Daniel Cohen-Or. Motionclip: Exposing human motion generation to clip space. European Conference on Computer Vision (ECCV), 2022.", + "[35] Guy Tevet, Sigal Raab, Brian Gordon, Yonatan Shafir, Amit H Bermano, and Daniel Cohen-Or. Human motion diffusion model. arXiv preprint arXiv:2209.14916, 2022.", + "[36] Sijie Yan, Zhizhong Li, Yuanjun Xiong, Huahan Yan, and Dahua Lin. Convolutional sequence generation for skeleton-based action synthesis. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 4393-4401, 2019.", + "[37] Hongwen Zhang, Yating Tian, Yuxiang Zhang, Mengcheng Li, Liang An, Zhenan Sun, and Yebin Liu. Pymaf-x: Towards well-aligned full-body model regression from monocular images. arXiv preprint arXiv:2207.06400, 2022.", + "[38] Mingyuan Zhang, Zhongang Cai, Liang Pan, Fangzhou Hong, Xinying Guo, Lei Yang, and Ziwei Liu. Motiondiffuse: Text-driven human motion generation with diffusion model. arXiv preprint arXiv:2208.15001, 2022.", + "[39] Yifei Zhang, Rania Briq, Julian Tanke, and Juergen Gall. Adversarial synthesis of human pose from text. 42nd DAGM German Conference of Pattern Recognition, pages 145-158, 2021.", + "[40] Rui Zhao, Hui Su, and Qiang Ji. Bayesian adversarial human motion synthesis. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 6224-6233, 2020.", + "[41] Xingran Zhou, Siyu Huang, Bin Li, Yingming Li, Jiachen Li, and Zhongfei Zhang. Text guided person image synthesis. Proceedings IEEE Conf. on Computer Vision and Pattern Recognition (CVPR), 2019." + ], + "bbox": [ + 503, + 92, + 890, + 867 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "15048", + "bbox": [ + 480, + 945, + 519, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/0b6ce6f5-40a5-4972-8f2c-3c7fc7288f3d_model.json b/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/0b6ce6f5-40a5-4972-8f2c-3c7fc7288f3d_model.json new file mode 100644 index 0000000000000000000000000000000000000000..973dcfdd533bab91e678ee1bde97e709602ea868 --- /dev/null +++ b/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/0b6ce6f5-40a5-4972-8f2c-3c7fc7288f3d_model.json @@ -0,0 +1,2167 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.182, + 0.131, + 0.79, + 0.175 + ], + "angle": 0, + "content": "Make-An-Animation: Large-Scale Text-conditional 3D Human Motion Generation" + }, + { + "type": "text", + "bbox": [ + 0.129, + 0.204, + 0.258, + 0.221 + ], + "angle": 0, + "content": "Samaneh Azadi" + }, + { + "type": "text", + "bbox": [ + 0.3, + 0.204, + 0.396, + 0.221 + ], + "angle": 0, + "content": "Akbar Shah" + }, + { + "type": "text", + "bbox": [ + 0.438, + 0.204, + 0.558, + 0.238 + ], + "angle": 0, + "content": "Thomas Hayes Meta AI" + }, + { + "type": "text", + "bbox": [ + 0.601, + 0.204, + 0.698, + 0.221 + ], + "angle": 0, + "content": "Devi Parikh" + }, + { + "type": "text", + "bbox": [ + 0.739, + 0.204, + 0.842, + 0.223 + ], + "angle": 0, + "content": "Sonal Gupta" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.274, + 0.314, + 0.29 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.306, + 0.474, + 0.668 + ], + "angle": 0, + "content": "Text-guided human motion generation has drawn significant interest because of its impactful applications spanning animation and robotics. Recently, application of diffusion models for motion generation has enabled improvements in the quality of generated motions. However, existing approaches are limited by their reliance on relatively small-scale motion capture data, leading to poor performance on more diverse, in-the-wild prompts. In this paper, we introduce Make-An-Animation, a text-conditioned human motion generation model which learns more diverse poses and prompts from large-scale image-text datasets, enabling significant improvement in performance over prior works. Make-An-Animation is trained in two stages. First, we train on a curated large-scale dataset of (text, static pseudo-pose) pairs extracted from image-text datasets. Second, we fine-tune on motion capture data, adding additional layers to model the temporal dimension. Unlike prior diffusion models for motion generation, Make-An-Animation uses a U-Net architecture similar to recent text-to-video generation models. Human evaluation of motion realism and alignment with input text shows that our model reaches state-of-the-art performance on text-to-motion generation. Generated samples can be viewed at https://azadis.github.io/make-an-animation." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.694, + 0.21, + 0.71 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.471, + 0.901 + ], + "angle": 0, + "content": "As the world shifts towards virtual spaces, and as embodied agents become more capable, it will be increasingly important to be able to generate plausible human motion. Speech or text are perhaps the most natural ways to prompt generative models, which is one reason behind the explosion in text-to-x generation research. Human motion generation from text has diverse applications both in virtual and real worlds. For instance, it enables control of robots with speech, faster video game development, creation of special effects featuring humans, as well as novel metaverse user-interaction modes whereby users can control the actions of their or others' avatars via voice or text." + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.301, + 0.903, + 0.427 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.596, + 0.433, + 0.838, + 0.445 + ], + "angle": 0, + "content": "A person is chopping down a tree with an axe." + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.46, + 0.902, + 0.598 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.654, + 0.604, + 0.774, + 0.616 + ], + "angle": 0, + "content": "A person is ice skating." + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.632, + 0.895, + 0.702 + ], + "angle": 0, + "content": "Figure 1. Samples generated by Make-An-Animation for text conditional motion generation. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. In the top image, for a better visualization, frames are distributed horizontally." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.732, + 0.894, + 0.838 + ], + "angle": 0, + "content": "Text-conditioned human motion generation is challenging for a number of reasons. Firstly, there exists a huge diversity of human motions and text descriptions which describe those motions (i.e., the task is many-to-many distribution matching). Secondly, because motion capture data is expensive to acquire, human motion datasets are limited in scale and diversity." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.894, + 0.901 + ], + "angle": 0, + "content": "Recently, text-to-motion generation has seen rapid improvements in the quality and diversity of poses generated. In particular, diffusion models, which have yielded impressive results in text-conditioned image and video genera" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "15039" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.152 + ], + "angle": 0, + "content": "tion, have proven effective in generating human body poses [35, 16, 38]. However, these models struggle with in-the-wild prompts that are outside of the distribution of motion capture data." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.152, + 0.47, + 0.243 + ], + "angle": 0, + "content": "To address these shortcomings, we present Make-An-Animation, a text-conditioned human motion generation model which learns to map diverse human poses to natural language descriptions through in-the-wild image-text datasets and significantly improves on prior state-of-the-art models which only rely on motion capture data." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.243, + 0.468, + 0.394 + ], + "angle": 0, + "content": "Core to our approach is a large-scale dataset of human poses extracted from image-text datasets. Our key observation is that we should not be limited to learning human motion from motion capture data when we have access to large-scale in-the-wild video and images of human poses. So, to address the limited scale and diversity of motion capture datasets, we extract a large-scale Text Pseudo-Pose (TPP) dataset from image-text datasets filtered for images containing humans. This TPP dataset contains 35M (text, static pose) pairs." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.395, + 0.468, + 0.575 + ], + "angle": 0, + "content": "Make-An-Animation is trained in two stages: (1) We train a text-conditioned static 3D pose generation diffusion model on the TPP dataset. In this stage, Make-An-Animation learns the distribution of human poses and their alignment with text. (2) Then, we extend the pre-trained diffusion model to motion generation via the addition of temporal convolution and attention layers which model the new temporal dimension and train on widely-used motion capture data. In this second stage, the model learns motion, i.e., how to connect poses in a temporally coherent manner. Crucially, it does not have to re-learn the distribution of feasible poses or their alignment with text." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.576, + 0.468, + 0.711 + ], + "angle": 0, + "content": "The Make-An-Animation architecture is a U-Net, similar to recent text-to-video diffusion models. We condition the U-Net on text representations extracted from a language model trained on large-scale language data. We represent human motion as a sequence of 3D SMPL body parameters, with a 6D continuous SMPL representation for 21 body joints and the root orient. We additionally represent the global position per frame via a 3D vector indicating the position in each of the \\(x, y, z\\) dimensions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.712, + 0.468, + 0.772 + ], + "angle": 0, + "content": "Through human evaluation on a collected set of 400 diverse text prompts, we demonstrate that our method outperforms prior works in terms of generated pose realism and text alignment." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.773, + 0.38, + 0.787 + ], + "angle": 0, + "content": "To summarize, our main contributions are:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.799, + 0.468, + 0.859 + ], + "angle": 0, + "content": "- We present Make-An-Animation - a text-conditioned human motion generation model which improves on prior state-of-the-art models, especially on diverse, in-the-wild text prompts." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.871, + 0.468, + 0.901 + ], + "angle": 0, + "content": "- We show, for the first time, how to leverage large-scale image datasets to learn in-the-wild human poses" + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.799, + 0.468, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.531, + 0.092, + 0.892, + 0.182 + ], + "angle": 0, + "content": "for generation. We show through ablations that pretraining on our collected Text Pseudo-Pose dataset significantly improves the generalization to prompts outside the distribution of widely-used motion capture datasets while showing a comparable performance on the mocap test set." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.191, + 0.892, + 0.282 + ], + "angle": 0, + "content": "- We present a U-Net architecture for human motion generation which leverages a language model pretrained on large-scale language data and naturally extends a static text-to-pose generation diffusion model to motion generation via the addition of temporal convolution and attention layers." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.302, + 0.65, + 0.318 + ], + "angle": 0, + "content": "2. Related Works" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.327, + 0.892, + 0.403 + ], + "angle": 0, + "content": "Human pose and motion generation Prior works in human pose and motion synthesis have explored generative models either unconditionally [36, 40, 25], or conditioned on various input signals such as a prior motion [20, 29], an action class [11, 23, 5], or music [17, 18]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.403, + 0.892, + 0.583 + ], + "angle": 0, + "content": "Using text descriptions as a guidance in pose and motion synthesis has been a more recent research direction where many existing works use 2D keypoints as pose representations. [41] selects a base pose from 8 clusters based on an input text fed to a GAN model to generate a human image. [39] uses a GAN to generate a set of heatmaps for body keypoints conditioned on the text input. [28] proposes a coarse-to-fine approach where a refinement stage is introduced on top of the initial coarse estimate of the keypoints heatmaps. Different from the above methods, [3] uses SMPL to represent a 3D body pose, generated by an LSTM GAN from a text input." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.585, + 0.892, + 0.825 + ], + "angle": 0, + "content": "Many existing works approach text-to-motion by learning to align text and pose or motion embeddings in the feature space. JL2P [1] proposes to learn the joint embedding of text and pose using an autoencoder with curriculum learning. [7] proposes a two-stream model to encode upper and lower body motions separately. AvatarCLIP [15] uses a pre-trained VPoser model to generate candidate poses, which are then used to optimize a motion VAE. Motion-CLIP [34] trains an auto-encoder while simultaneously reconstructing motion and aligning the motion manifold with CLIP's latent space. TEMOS [24] trains a joint latent space through separate text and motion transformer encoders, allowing non-deterministic motion sampling. T2M [9] also uses a VAE model, but encodes motion as snippets and introduces an extra sampling for motion length conditioned on the input text." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Leveraging recent advancements in diffusion models, Motion Diffusion Model (MDM) [35], MotionDiffuse [38], and FLAME [16] adopt a diffusion process from text to motion with a transformer, which can significantly improve the diversity of synthesized samples. MDM and MotionDiffuse" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "15040" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.087, + 0.089, + 0.387, + 0.385 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.403, + 0.089, + 0.633, + 0.38 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.645, + 0.09, + 0.889, + 0.396 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.399, + 0.895, + 0.471 + ], + "angle": 0, + "content": "Figure 2. Make-An-Animation Model Architecture. Our diffusion model is built on a U-Net architecture inspired by recent image and video generation models. The U-Net consists of a sequence of Residual Blocks with 1x1 2D-convolution layers and Attention Blocks with cross-attention on textual information. To model the temporal dimension, we add 1D temporal convolution layers after each 1x1 2D-convolution, as well as temporal attention layers after each cross-attention layer. These temporal layers (greyed out in the figure) are only added in the motion fine-tuning stage." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.494, + 0.471, + 0.603 + ], + "angle": 0, + "content": "are trained on HumanML3D [9] which partially limits their choice of representation to stick figures for text-to-motion generation, while our curated large-scale dataset provides millions of SMPL pose labels. MDM supports converting poses from stick figures to SMPL bodies only through an optimization SIMPLIFY-X[22] procedure that often results in unrealistic body poses." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.628, + 0.47, + 0.719 + ], + "angle": 0, + "content": "Diffusion generative models Diffusion models are a class a generative model based on the thermodynamic stochastic diffusion process. In the forward diffusion process, a sample is drawn from the data distribution and is gradually noised by a diffusion process. A neural network learns the reverse process to gradually denoise the sample." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Diffusion models have recently enabled rapid advancements in image generation. [13] first demonstrated diffusion models for unconditional image generation. In comparison to GANs [8] and VAEs, diffusion models have shown superior training stability, avoid mode dropout, and yield stronger performance. Adapting diffusion models for conditional generation, [6] introduced classifier-guided diffusion. More recently, classifier free guidance [14] has been introduced to enable conditioning without the need for a separate classifier. Imagen [30] showed that conditioning on text embeddings extracted from a pre-trained language model enhanced text alignment, and that perfor" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.494, + 0.895, + 0.617 + ], + "angle": 0, + "content": "mance improved with text encoder size. Our U-Net architecture shares similarities withImagen. Namely, Make-An-Animation uses the same text encoder, T5-XXL [26], and a similar U-Net architecture. Other improvements have been suggested to improve training stability and performance, such as learning the reverse diffusion variances [21] and v-parameterization [31]. Our method leverages both of these improvements." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.627, + 0.849, + 0.643 + ], + "angle": 0, + "content": "3. Text-to-3D Human Motion Generation" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.651, + 0.597, + 0.667 + ], + "angle": 0, + "content": "3.1. Dataset" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.674, + 0.895, + 0.903 + ], + "angle": 0, + "content": "3D Human motion datasets. We use the AMASS dataset of 3D human motions [19] and its textual annotations from the HumanML3D dataset [10]. We borrow the original SMPL annotations from AMASS instead of the processed data from HumanML3D dataset since (1) we found their motion representation contains redundant information, and (2) an extra optimization step would be required to convert their motion representations to the original SMPL format resulting in a degradation in the quality and speed of motion generation in the SMPL format. Similar to HumanML3D, we double the size of the dataset by mirroring the motions and editing the textual description accordingly, resulting in 26850 motion examples in the training set. Additionally, we benefit from the GTA-Human dataset [4] built from an open-world action game providing SMPL annotations over" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "15041" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.092, + 0.179, + 0.171 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.186, + 0.092, + 0.274, + 0.17 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.285, + 0.097, + 0.374, + 0.17 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.38, + 0.097, + 0.477, + 0.17 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.1, + 0.177, + 0.445, + 0.192 + ], + "angle": 0, + "content": "Figure 3. A few examples from our collected TPP dataset." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.216, + 0.47, + 0.276 + ], + "angle": 0, + "content": "laid on the virtual humans for 20000 motion samples. This dataset does not have any textual annotation, thus we use it for an unconditional training of our model simultaneous to its text-conditional training." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.277, + 0.469, + 0.337 + ], + "angle": 0, + "content": "Since the existing mocap datasets are limited in the number of samples and their diversity, we also collected a large-scale dataset of in-the-wild human poses from image datasets as follows." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.355, + 0.47, + 0.581 + ], + "angle": 0, + "content": "Large-scale Text Pseudo-Pose (TPP) dataset. Similar to [2], we have collected a dataset containing 35M pairs of human poses and their text descriptions from a few large-scale image-text datasets. We processed all images by running Detectron2 keypoint detector to find images with a single human, then extracted their 3D pseudo-pose SMPL annotations using a pre-trained PyMAF-X model [37]. We used the publicly available captions without any processing. This large-scale data overcomes the limitations of the existing mocap datasets by providing a wide variety of human poses and a huge number of (text, 3D pose) sample pairs despite being noisy. We do not extract any face or hand expressions from the aforementioned datasets. A few examples of the (pseudo-pose, text) pairs are shown in Figure 3." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.591, + 0.345, + 0.607 + ], + "angle": 0, + "content": "3.2. Diffusion Models Background" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.614, + 0.469, + 0.766 + ], + "angle": 0, + "content": "Diffusion models are a class of generative model that convert Gaussian noise into samples from a learned distribution by iterative denoising. The forward process is a Gaussian noisin processing following a Markove chain, \\(\\{x_{t}\\}_{t = 0}^{T}\\) where \\(x_0\\) is drawn from the data distribution, in our case a set of 3D SMPL body poses. We can express the forward process as \\(q(x_{t}|x_{t - 1}) = \\mathcal{N}(\\sqrt{\\alpha_{t}} x_{t - 1},(1 - \\alpha_{t})\\mathbf{I})\\) where \\(\\alpha_{t}\\in (0,1)\\). As is standard in training diffusion models, we learn to reverse the forward process by minimizing a noise-prediction loss [13]:" + }, + { + "type": "equation", + "bbox": [ + 0.096, + 0.775, + 0.47, + 0.801 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {s i m p l e}} = \\mathbb {E} _ {\\epsilon \\sim \\mathcal {N} (0, \\mathbf {I}), t \\sim U [ 1, T ]} \\left[ \\| \\epsilon_ {t} - \\epsilon_ {\\theta} (x _ {t}, c, t) \\| _ {2} ^ {2} \\right] \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.468, + 0.841 + ], + "angle": 0, + "content": "where \\(c\\) is the optional conditioning for the diffusion model, which in our cases are text descriptions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.469, + 0.902 + ], + "angle": 0, + "content": "In addition to this simple loss, we follow [21, 27] and optimize the hybrid loss, which also uses a loss \\( L_{vlb} \\) that adds a constraint on the estimated variational lower bound (VLB). The \\( L_{vlb} \\) term is applied the same way as in [21]." + }, + { + "type": "table", + "bbox": [ + 0.518, + 0.089, + 0.877, + 0.205 + ], + "angle": 0, + "content": "
MethodR-Precision ↑FID ↓Diversity ↑
Real0.797±0.0020.002±0.0029.5±0.65
J2LP[[1]]0.486±.00211.02±.0467.676±.058
MDM[[35]]0.611±.0070.544±.0449.559±.086
T2M[[9]]0.740±.0031.067±.0029.188±.002
MAA0.6755±.0020.7740±0.0078.23±0.064
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.206, + 0.892, + 0.248 + ], + "angle": 0, + "content": "Table 1. Quantitative results on the HumanML3D test set. We run our evaluation 20 times and \\(\\pm\\) indicates the \\(95\\%\\) confidence interval." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.259, + 0.892, + 0.305 + ], + "angle": 0, + "content": "We follow [12, 31] and parameterize our models using \\( v \\)-parameterization (\\( v_{t} = \\alpha_{t}\\epsilon - \\sigma_{t}x \\)) rather than predicting \\( \\epsilon \\) or \\( x \\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.316, + 0.697, + 0.331 + ], + "angle": 0, + "content": "3.3. Make-An-Animation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.34, + 0.892, + 0.566 + ], + "angle": 0, + "content": "We represent an avatar body pose, \\( P \\), via 3D SMPL body parameters and an avatar motion as a sequence of body poses for \\( N \\) frames, \\( [P_1, P_2, \\dots, P_N] \\). We use 6D continuous SMPL representation for 21 body joints and the root orient. We additionally represent the global position per frame via a 3D vector indicating the avatar's position in each of the \\( x, y, z \\) dimensions, resulting in each \\( P_i \\in \\mathbb{R}^{135} \\). Make-An-Animation is built from three major components: (1) a pre-trained language model trained on a large-scale language data (T5-XXL [26]), (2) a text-to-3D diffusion based pose generation model trained on our collected TPP dataset, and (3) a set of temporal convolution and attention layers extending the static pose generation model to the temporal dimension for motion generation and capturing the dependencies between the frames." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.567, + 0.892, + 0.733 + ], + "angle": 0, + "content": "We follow [12] and use v-prediction parameterization \\((v_{t} = \\alpha_{t}\\epsilon -\\sigma_{t}x)\\) to train our pose and motion diffusion models for numerical stability. Our denoising model in the above U-Net architecture operates on all motion frames at the same time resulting in a higher temporal coherence in the generated motions compared to the autoregressive frameworks [35] and does not require any specific loss on the motion velocity for a smooth motion synthesis. We also benefit from classifier free guidance [14] at inference by conditioning our model on a null text during training for \\(10\\%\\) of the time." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.755, + 0.747, + 0.77 + ], + "angle": 0, + "content": "3.3.1 Text-to-3D Pose Generation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.892, + 0.901 + ], + "angle": 0, + "content": "We train a U-Net based diffusion model to generate 3D SMPL pose parameters conditioning on text embeddings from a large frozen language model [26]. Inspired by the image and video generation models [32], we reshape the pose inputs to \\( B \\times C \\times 1 \\times 1 \\) with \\( B \\) and \\( C \\) indicating batch size and channel dimension of 135, respectively. Our U-Net model is built from a sequence of (1) Residual blocks with 1x1 2D-convolution layers conditioned on the diffu" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "15042" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.102, + 0.116, + 0.45, + 0.254 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.117, + 0.258, + 0.457, + 0.27 + ], + "angle": 0, + "content": "(a) Which motion corresponds better with the textual description?" + }, + { + "type": "image", + "bbox": [ + 0.511, + 0.117, + 0.846, + 0.255 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.587, + 0.258, + 0.761, + 0.269 + ], + "angle": 0, + "content": "(b) Which motion is more realistic?" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.286, + 0.895, + 0.327 + ], + "angle": 0, + "content": "Figure 4. Human Evaluation. Here we compare each baseline against our model, MAA, in terms of text alignment and motion realism. The results are reported as the percentage of the majority vote raters that preferred our method to each baseline on our curated 400 prompts set." + }, + { + "type": "image", + "bbox": [ + 0.096, + 0.362, + 0.441, + 0.499 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.506, + 0.471, + 0.576 + ], + "angle": 0, + "content": "Figure 5. Ablation Study. Here we compare each ablated model against our model, MAA, in terms text alignment and motion realism. The results are reported as the percentage of the majority vote raters that preferred our method to each baseline on our curated 400 prompts set." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.601, + 0.47, + 0.678 + ], + "angle": 0, + "content": "sion time-step embedding and text embedding, and (2) Attention Blocks attending to the textual information and the diffusion time-step. We train this network on our large-scale TPP dataset where we set translation parameters to zero in all training examples, i.e., human at the center of the scene." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.696, + 0.353, + 0.712 + ], + "angle": 0, + "content": "3.3.2 Temporal and Attention Layers" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.47, + 0.779 + ], + "angle": 0, + "content": "In order to expand the aforementioned pose generation model to learn the temporal dimension for motion generation, we modify the convolutional and attention layers of the U-Net as follows." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.781, + 0.471, + 0.901 + ], + "angle": 0, + "content": "We reshape the input motion sequence to a tensor of shape \\( B \\times C \\times N \\times 1 \\times 1 \\), where \\( C \\) is the length of the pose representation and \\( N \\) is the number of frames. Inspired by [32, 12], we stack a 1D temporal convolution layer following each 1x1 2D-convolution. This allows us to train the new 1D temporal layers from scratch while loading the pre-trained convolution weights from the pose generation model. We set the kernel size of these temporal convolution" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.351, + 0.892, + 0.442 + ], + "angle": 0, + "content": "layers to 3 opposed to the unit kernel size of the 2D convolutions. We apply a similar dimension decomposition strategy to the attention layers, where we stack a newly initialized temporal attention layer to each pre-trained attention block from the pose generation network. For the temporal attention layers we utilize a Rotary Position Embedding [33]." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.453, + 0.634, + 0.47 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.479, + 0.892, + 0.553 + ], + "angle": 0, + "content": "We compare the performance of our motion generation model with the existing state-of-the-art text-to-human-motion generation models through human evaluation on 400 crowd-sourced prompts and automatic metrics on the HumanML3D test set." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.561, + 0.681, + 0.575 + ], + "angle": 0, + "content": "4.1. Automatic Metrics" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.584, + 0.892, + 0.901 + ], + "angle": 0, + "content": "We perform an automatic evaluation on the HumanML3D test set in terms of Fréchet Distance (FID), R-Precision and Diversity scores. FID measures both diversity and quality of the samples comparing its distribution with the ground truth test set while R-Precision measures faithfulness between each generated motion and its input prompt. Diversity measures the variance of the generated motions across all descriptions. To compute the above scores, a motion encoder was jointly trained with a text encoder via a contrastive loss by [9]. We use the same encoder to extract text and motion embeddings. Since this model has been trained and optimized on the 263-dimensional pose representation vector, we transform both the ground-truth SMPL data and our generated samples similarly following the transformations provided by [11] before computing the above metrics. We upsample our generations to 196 frames and keep that fixed for the ground truth samples and our outputs while computing the above metrics. Opposed to our baselines, we have not optimized our model on the 263-dimensional motion representation, but achieve a comparable performance in all metrics as reported in Table 1." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "15043" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.077, + 0.091, + 0.262, + 0.106 + ], + "angle": 0, + "content": "4.2. Human Evaluation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.115, + 0.474, + 0.449 + ], + "angle": 0, + "content": "To evaluate the generalization ability of our model in synthesizing more challenging human poses and motions, we collected an evaluation set from Amazon Mechanical Turk (AMT) that consists of 400 prompts. We asked annotators for prompts that described an action along with some context of the scene. We filtered out prompts based on ethical concerns to remove any references to children or NSFW content. These prompts were selected without generating any poses or images for them, and were kept fixed for all of our evaluations. This test set is released here1. We generated animated poses from all models with no translation to measure the correctness and quality of the body pose and motion. We show raters a text description and the corresponding rendered avatars from two models and ask them which output better matches the input text. For each comparison, we use the majority vote from 7 different annotators on 400 prompts as the final result, reported in Figure 4. This study confirms the superiority of our model and the impact of our large-scale TPP dataset in human motion generation and overcoming the limitations of the mocap datasets. A few motion samples generated by our model are shown in Figure 8 and more are included on our webpage1." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.459, + 0.245, + 0.473 + ], + "angle": 0, + "content": "4.3. Ablation Studies" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.482, + 0.473, + 0.814 + ], + "angle": 0, + "content": "To disentangle and study the impact of our U-Net architecture versus the impact on our TPP dataset on our results, we implemented and trained an alternative diffusion model as a decoder-only transformer with a causal attention mask to generate 3D pose representations from text. This model operates on a sequence of tokenized captions and their text embeddings, the diffusion time-step embedding, the noised body pose and root orient representations, and two final pose and orientation queries to predict the unnoised pose and root orientation, respectively. We pre-trained this model on our TPP dataset, then expanded the model for motion synthesis via adding three additional tokens per frame for pose, root orient, and translation paramters. We trained this model on the mocap datasets described in Sec 3.1 and compared its performance with our U-Net model via Amazon Mechanical Turk. As a result, \\(58\\%\\) of the raters preferred the generations from our U-Net architecture. This experiment confirms the superiority of the U-Net model versus its auto-regressive alternatives. We also ablated the impact of temporal attention modules on the final quality of the samples resulting in \\(54\\%\\) of the users preferring samples from a U-Net with temporal attention." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.815, + 0.471, + 0.86 + ], + "angle": 0, + "content": "Training with the GTA data unconditionally made the convergence of the model faster although it didn't impact the samples' quality after convergence." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.861, + 0.471, + 0.877 + ], + "angle": 0, + "content": "Additionally, we experimented with training our U-Net" + }, + { + "type": "image_caption", + "bbox": [ + 0.547, + 0.184, + 0.565, + 0.344 + ], + "angle": 270, + "content": "A person is playing football in playground" + }, + { + "type": "image", + "bbox": [ + 0.585, + 0.099, + 0.862, + 0.203 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.586, + 0.208, + 0.862, + 0.316 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.585, + 0.318, + 0.862, + 0.421 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.549, + 0.57, + 0.565, + 0.687 + ], + "angle": 270, + "content": "A person dancing in the street" + }, + { + "type": "image", + "bbox": [ + 0.586, + 0.457, + 0.862, + 0.56 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.586, + 0.566, + 0.862, + 0.667 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.586, + 0.669, + 0.862, + 0.77 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.773, + 0.895, + 0.857 + ], + "angle": 0, + "content": "Figure 6. Diverse samples generated by Make-An-Animation for text conditional motion generation. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. For a better visualization, frames are down-sampled along the temporal dimension and distributed horizontally." + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.33, + 0.901 + ], + "angle": 0, + "content": "1 https://azadis.github.io/make-an-animation" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "15044" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.189, + 0.093, + 0.3, + 0.104 + ], + "angle": 0, + "content": "MAA Generations" + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.114, + 0.468, + 0.26 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.154, + 0.261, + 0.347, + 0.272 + ], + "angle": 0, + "content": "A person wrestles a bear in the forest" + }, + { + "type": "image_caption", + "bbox": [ + 0.596, + 0.093, + 0.768, + 0.105 + ], + "angle": 0, + "content": "Nearest Neighbour Example" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.116, + 0.892, + 0.259 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.607, + 0.26, + 0.793, + 0.27 + ], + "angle": 0, + "content": "a person puts both arms into the air" + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.294, + 0.468, + 0.435 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.185, + 0.437, + 0.343, + 0.448 + ], + "angle": 0, + "content": "A person is practicing the flute" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.294, + 0.892, + 0.436 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.61, + 0.437, + 0.779, + 0.448 + ], + "angle": 0, + "content": "a person clapping with his hands" + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.464, + 0.468, + 0.605 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.154, + 0.611, + 0.38, + 0.623 + ], + "angle": 0, + "content": "A person is sawing a branch off of a tree" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.464, + 0.891, + 0.606 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.524, + 0.609, + 0.875, + 0.632 + ], + "angle": 0, + "content": "a man raises his hands to his chest, claps them together, then lowers them back to his sides" + }, + { + "type": "image_caption", + "bbox": [ + 0.075, + 0.637, + 0.893, + 0.692 + ], + "angle": 0, + "content": "Figure 7. Left: samples generated by Make-An-Animation for text conditional motion generation. Right: The nearest neighbor example for each of the generated samples found from the mocap training set based on motion and text clip similarity scores. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. For a better visualization, frames are distributed horizontally." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.718, + 0.469, + 0.824 + ], + "angle": 0, + "content": "model on the mocap training set from scratch and without pre-training. However, we observed stability and convergence issues in this setting even with various learning rates and warming up updates. The pre-training stage on the large-scale dataset was therefore a stable solution resulting in high quality motion samples in the end. All ablation results are summarized in Figure 5." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.833, + 0.26, + 0.849 + ], + "angle": 0, + "content": "4.4. Qualitative Studies" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.47, + 0.901 + ], + "angle": 0, + "content": "In Figure 7, we visualize the generalization capability of our model in synthesizing novel motions. We investigate the existence of similar prompts or motions in the train" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.718, + 0.892, + 0.9 + ], + "angle": 0, + "content": "ing data for each synthesized motion via a nearest neighbor search. We extract the motion embedding and text embedding for each sample in our test set of prompts as well as our mocap training data using a pre-trained motionCLIP model [34, 16] that has learned a joint motion and language embedding space. For each synthesized motion, we find the top 6 motions and prompts from the training data with the highest cosine similarity scores. As shown in the figure, our model has generalized to new motions that did not exist in the training data. In addition, Figure 6 illustrates multiple diverse motions generated by our model for different text prompt." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "15045" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.097, + 0.46, + 0.248 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.154, + 0.251, + 0.37, + 0.262 + ], + "angle": 0, + "content": "A person is doing a handstand on a cactus" + }, + { + "type": "image", + "bbox": [ + 0.514, + 0.125, + 0.892, + 0.248 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.621, + 0.249, + 0.763, + 0.26 + ], + "angle": 0, + "content": "A person kicks a soccer ball" + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.277, + 0.457, + 0.415 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.142, + 0.417, + 0.356, + 0.429 + ], + "angle": 0, + "content": "A person is rowing a small dingy in a river" + }, + { + "type": "image", + "bbox": [ + 0.514, + 0.268, + 0.891, + 0.416 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.557, + 0.417, + 0.818, + 0.429 + ], + "angle": 0, + "content": "A person is playing tennis at the Recreation Center" + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.443, + 0.457, + 0.581 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.166, + 0.583, + 0.345, + 0.594 + ], + "angle": 0, + "content": "A volleyball player bumps a ball up" + }, + { + "type": "image", + "bbox": [ + 0.514, + 0.445, + 0.891, + 0.581 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.576, + 0.583, + 0.814, + 0.595 + ], + "angle": 0, + "content": "A photographer is looking through the camera" + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.605, + 0.452, + 0.738 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.121, + 0.739, + 0.378, + 0.75 + ], + "angle": 0, + "content": "A person is shoveling the driveway after a blizzard" + }, + { + "type": "image", + "bbox": [ + 0.514, + 0.618, + 0.891, + 0.738 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.595, + 0.739, + 0.796, + 0.75 + ], + "angle": 0, + "content": "A person is sitting down on the ground" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.766, + 0.893, + 0.794 + ], + "angle": 0, + "content": "Figure 8. Samples generated by Make-An-Animation for text conditional motion generation. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. For a better visualization, frames are distributed horizontally." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.818, + 0.195, + 0.833 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Current text-to-motion models are hindered by relatively small-scale motion capture datasets, as evident by their poor performance on more diverse, in-the-wild prompts." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.819, + 0.894, + 0.896 + ], + "angle": 0, + "content": "Motivated by this shortcoming, we present Make-An-Animation, a human motion generation model trained on a collection of large-scale static pseudo-pose and motion capture data. As we demonstrate through our ablations and human studies comparing to prior works, pre-training on the" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "15046" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.212 + ], + "angle": 0, + "content": "large-scale TPP dataset significantly improves performance on captions outside of the distribution of motion capture data. Furthermore, our novel U-Net architecture enables a seamless transition between static pose pre-training and dynamic pose (i.e., motion) fine-tuning. Altogether, this work paves the way to leverage large-scale image and video datasets for learning generation of human 3D pose parameters." + }, + { + "type": "title", + "bbox": [ + 0.502, + 0.091, + 0.597, + 0.105 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.115, + 0.892, + 0.169 + ], + "angle": 0, + "content": "[1] Chaitanya Ahuja and Louis-Philippe Morency. Language2pose: Natural language grounded pose forecasting. IEEE International Conference on 3D Vision (3DV), pages 719-728, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.171, + 0.894, + 0.225 + ], + "angle": 0, + "content": "[2] Samaneh Azadi, Thomas Hayes, Akbar Shah, Guan Pang, Devi Parikh, and Sonal Gupta. Text-conditional contextualized avatars for zero-shot personalization. arXiv preprint arXiv:2304.07410, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.228, + 0.895, + 0.268 + ], + "angle": 0, + "content": "[3] Rania Briq, Pratika Kochar, and Juergen Gall. Towards better adversarial synthesis of human images from text. arXiv preprint arXiv:2107.01869, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.271, + 0.895, + 0.323 + ], + "angle": 0, + "content": "[4] Zhongang Cai, Mingyuan Zhang, Jiawei Ren, Chen Wei, Daxuan Ren, Zhengyu Lin, Haiyu Zhao, Lei Yang, and Zwei Liu. Playing for 3d human recovery. arXiv preprint arXiv:2110.07588, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.326, + 0.895, + 0.38 + ], + "angle": 0, + "content": "[5] Pablo Cervantes, Yusuke Sekikawa, Ikuro Sato, and Koichi Shinoda. Implicit neural representations for variable length human motion generation. European Conference on Computer Vision (ECCV), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.382, + 0.892, + 0.424 + ], + "angle": 0, + "content": "[6] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Advances in Neural Information Processing Systems (NeurIPS), 34, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.425, + 0.892, + 0.493 + ], + "angle": 0, + "content": "[7] Anindita Ghosh, Noshaba Cheema, Cennet Oguz, Christian Theobalt, and Philipp Slusallek. Synthesis of compositional animations from textual descriptions. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 1396-1406, October 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.495, + 0.892, + 0.549 + ], + "angle": 0, + "content": "[8] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In Advances in Neural Information Processing Systems, 2014." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.551, + 0.892, + 0.62 + ], + "angle": 0, + "content": "[9] Chuan Guo, Shihao Zou, Xinxin Zuo, Sen Wang, Wei Ji, Xingyu Li, and Li Cheng. Generating diverse and natural 3d human motions from text. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 5152-5161, June 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.621, + 0.892, + 0.689 + ], + "angle": 0, + "content": "[10] Chuan Guo, Shihao Zou, Xinxin Zuo, Sen Wang, Wei Ji, Xingyu Li, and Li Cheng. Generating diverse and natural 3d human motions from text. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 5152-5161, June 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.691, + 0.892, + 0.759 + ], + "angle": 0, + "content": "[11] Chuan Guo, Xinxin Zuo, Sen Wang, Shihao Zou, Qingyao Sun, Annan Deng, Minglun Gong, and Li Cheng. Action2motion: Conditioned generation of 3d human motions. Proceedings of the 28th ACM International Conference on Multimedia, pages 2021-2029, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.761, + 0.892, + 0.829 + ], + "angle": 0, + "content": "[12] Jonathan Ho, William Chan, Chitwan Saharia, Jay Whang, Ruiqi Gao, Alexey Gritsenko, Diederik P Kingma, Ben Poole, Mohammad Norouzi, David J Fleet, et al. Imagen video: High definition video generation with diffusion models. arXiv preprint arXiv:2210.02303, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.831, + 0.892, + 0.871 + ], + "angle": 0, + "content": "[13] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Advances in Neural Information Processing Systems (NeurIPS), 33, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.873, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[14] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. arXiv preprint arXiv:2207.12598, 2022." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.115, + 0.895, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.956 + ], + "angle": 0, + "content": "15047" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[15] Fangzhou Hong, Mingyuan Zhang, Liang Pan, Zhongang Cai, Lei Yang, and Ziwei Liu. Avatarclip: Zero-shot text-driven generation and animation of 3d avatars. ACM Transactions on Graphics (TOG), 41(4):1-19, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.151, + 0.47, + 0.192 + ], + "angle": 0, + "content": "[16] Jihoon Kim, Jiseob Kim, and Sungjoon Choi. Flame: Freeform language-based motion synthesis & editing. arXiv preprint arXiv:2209.00349, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.195, + 0.469, + 0.249 + ], + "angle": 0, + "content": "[17] Hsin-Ying Lee, Xiaodong Yang, Ming-Yu Liu, Ting-Chun Wang, Yu-Ding Lu, Ming-Hsuan Yang, and Jan Kautz. Dancing to music. Advances in Neural Information Processing Systems (NeurIPS), 32, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.253, + 0.469, + 0.308 + ], + "angle": 0, + "content": "[18] Ruilong Li, Shan Yang, David A. Ross, and Angjoo Kanazawa. Ai choreographer: Music conditioned 3d dance generation with aist++. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.311, + 0.469, + 0.365 + ], + "angle": 0, + "content": "[19] Naureen Mahmood, Nima Ghorbani, Nikolaus F. Troje, Gerard Pons-Moll, and Michael J. Black. AMASS: Archive of motion capture as surface shapes. In International Conference on Computer Vision, pages 5442-5451, Oct. 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.369, + 0.469, + 0.423 + ], + "angle": 0, + "content": "[20] Julieta Martinez, Michael J. Black, and Javier Romero. On human motion prediction using recurrent neural networks. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.427, + 0.469, + 0.48 + ], + "angle": 0, + "content": "[21] Alexander Quinn Nichol and Prafulla Dhariwal. Improved denoising diffusion probabilistic models. In International Conference on Machine Learning, pages 8162-8171. PMLR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.485, + 0.469, + 0.553 + ], + "angle": 0, + "content": "[22] Georgios Pavlakos, Vasileios Choutas, Nima Ghorbani, Timo Bolkart, Ahmed A. A. Osman, Dimitrios Tzionas, and Michael J. Black. Expressive body capture: 3d hands, face, and body from a single image. In Conference on Computer Vision and Pattern Recognition (CVPR), 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.557, + 0.469, + 0.624 + ], + "angle": 0, + "content": "[23] Mathis Petrovich, Michael J. Black, and Gül Varol. Action-conditioned 3D human motion synthesis with transformer VAE. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 10985-10995, October 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.629, + 0.469, + 0.669 + ], + "angle": 0, + "content": "[24] Mathis Petrovich, Michael J. Black, and Gül Varol. Temos: Generating diverse human motions from textual descriptions. European Conference on Computer Vision (ECCV), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.673, + 0.469, + 0.727 + ], + "angle": 0, + "content": "[25] Sigal Raab, Inbal Leibovitch, Peizhuo Li, Kfir Aberman, Olga Sorkine-Hornung, and Daniel Cohen-Or. Modi: Unconditional motion synthesis from diverse data. arXiv preprint arXiv:2206.08010, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.731, + 0.469, + 0.784 + ], + "angle": 0, + "content": "[26] Colin Raffel, Noam Shazeer, Adam Roberts, Katherine Lee, Sharan Narang, Michael Matena, Yanqi Zhou, Wei Li, and Peter J. Liu. Exploring the limits of transfer learning with a unified text-to-text transformer. JMLR, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.788, + 0.469, + 0.841 + ], + "angle": 0, + "content": "[27] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.846, + 0.469, + 0.9 + ], + "angle": 0, + "content": "[28] Prasun Roy, Subhankar Ghosh, Saumik Bhattacharya, Umapada Pal, and Michael Blumenstein. Tips: Text-induced pose synthesis. European Conference on Computer Vision (ECCV), 2022." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "[29] Alejandro Hernandez Ruiz, Juergen Gall, and Francesc Moreno-Noguer. Human motion prediction via spatiotemporal inpainting. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.15, + 0.892, + 0.245 + ], + "angle": 0, + "content": "[30] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S. Sara Mahdavi, Rapha Gontijo Lopes, Tim Salimans, Jonathan Ho, David J Fleet, and Mohammad Norouzi. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.249, + 0.892, + 0.288 + ], + "angle": 0, + "content": "[31] T. Salimans and J Ho. Progressive distillation for fast sampling of diffusion models. International Conference on Learning Representations, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.291, + 0.892, + 0.357 + ], + "angle": 0, + "content": "[32] Uriel Singer, Adam Polyak, Thomas Hayes, Xi Yin, Jie An, Songyang Zhang, Qiyuan Hu, Harry Yang, Oron Ashual, Oran Gafni, et al. Make-a-video: Text-to-video generation without text-video data. arXiv preprint arXiv:2209.14792, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.362, + 0.892, + 0.414 + ], + "angle": 0, + "content": "[33] Jianlin Su, Yu Lu, Shengfeng Pan, Ahmed Murtadha, Bo Wen, and Yunfeng Liu. Roformer: Enhanced transformer with rotary position embedding. arXiv preprint arXiv:2104.09864, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.418, + 0.892, + 0.471 + ], + "angle": 0, + "content": "[34] Guy Tevet, Brian Gordon, Amir Hertz, Amit H. Bermano, and Daniel Cohen-Or. Motionclip: Exposing human motion generation to clip space. European Conference on Computer Vision (ECCV), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.475, + 0.892, + 0.514 + ], + "angle": 0, + "content": "[35] Guy Tevet, Sigal Raab, Brian Gordon, Yonatan Shafir, Amit H Bermano, and Daniel Cohen-Or. Human motion diffusion model. arXiv preprint arXiv:2209.14916, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.518, + 0.892, + 0.584 + ], + "angle": 0, + "content": "[36] Sijie Yan, Zhizhong Li, Yuanjun Xiong, Huahan Yan, and Dahua Lin. Convolutional sequence generation for skeleton-based action synthesis. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 4393-4401, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.588, + 0.892, + 0.642 + ], + "angle": 0, + "content": "[37] Hongwen Zhang, Yating Tian, Yuxiang Zhang, Mengcheng Li, Liang An, Zhenan Sun, and Yebin Liu. Pymaf-x: Towards well-aligned full-body model regression from monocular images. arXiv preprint arXiv:2207.06400, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.645, + 0.892, + 0.698 + ], + "angle": 0, + "content": "[38] Mingyuan Zhang, Zhongang Cai, Liang Pan, Fangzhou Hong, Xinying Guo, Lei Yang, and Ziwei Liu. Motiondiffuse: Text-driven human motion generation with diffusion model. arXiv preprint arXiv:2208.15001, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.701, + 0.892, + 0.754 + ], + "angle": 0, + "content": "[39] Yifei Zhang, Rania Briq, Julian Tanke, and Juergen Gall. Adversarial synthesis of human pose from text. 42nd DAGM German Conference of Pattern Recognition, pages 145-158, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.758, + 0.892, + 0.811 + ], + "angle": 0, + "content": "[40] Rui Zhao, Hui Su, and Qiang Ji. Bayesian adversarial human motion synthesis. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 6224-6233, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.814, + 0.892, + 0.868 + ], + "angle": 0, + "content": "[41] Xingran Zhou, Siyu Huang, Bin Li, Yingming Li, Jiachen Li, and Zhongfei Zhang. Text guided person image synthesis. Proceedings IEEE Conf. on Computer Vision and Pattern Recognition (CVPR), 2019." + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.868 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.52, + 0.957 + ], + "angle": 0, + "content": "15048" + } + ] +] \ No newline at end of file diff --git a/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/0b6ce6f5-40a5-4972-8f2c-3c7fc7288f3d_origin.pdf b/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/0b6ce6f5-40a5-4972-8f2c-3c7fc7288f3d_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..57d3d8d9c8f56c75e3410e1fbe5468fa10517626 --- /dev/null +++ b/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/0b6ce6f5-40a5-4972-8f2c-3c7fc7288f3d_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:f8e6140fcfdb45f38cdae0dbf213dcdec24c76a4e8435205f0ea77b402552acb +size 3090830 diff --git a/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/full.md b/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/full.md new file mode 100644 index 0000000000000000000000000000000000000000..118c5379045e9deec6c94bcd4ab446b92d67bcdf --- /dev/null +++ b/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/full.md @@ -0,0 +1,288 @@ +# Make-An-Animation: Large-Scale Text-conditional 3D Human Motion Generation + +Samaneh Azadi + +Akbar Shah + +Thomas Hayes Meta AI + +Devi Parikh + +Sonal Gupta + +# Abstract + +Text-guided human motion generation has drawn significant interest because of its impactful applications spanning animation and robotics. Recently, application of diffusion models for motion generation has enabled improvements in the quality of generated motions. However, existing approaches are limited by their reliance on relatively small-scale motion capture data, leading to poor performance on more diverse, in-the-wild prompts. In this paper, we introduce Make-An-Animation, a text-conditioned human motion generation model which learns more diverse poses and prompts from large-scale image-text datasets, enabling significant improvement in performance over prior works. Make-An-Animation is trained in two stages. First, we train on a curated large-scale dataset of (text, static pseudo-pose) pairs extracted from image-text datasets. Second, we fine-tune on motion capture data, adding additional layers to model the temporal dimension. Unlike prior diffusion models for motion generation, Make-An-Animation uses a U-Net architecture similar to recent text-to-video generation models. Human evaluation of motion realism and alignment with input text shows that our model reaches state-of-the-art performance on text-to-motion generation. Generated samples can be viewed at https://azadis.github.io/make-an-animation. + +# 1. Introduction + +As the world shifts towards virtual spaces, and as embodied agents become more capable, it will be increasingly important to be able to generate plausible human motion. Speech or text are perhaps the most natural ways to prompt generative models, which is one reason behind the explosion in text-to-x generation research. Human motion generation from text has diverse applications both in virtual and real worlds. For instance, it enables control of robots with speech, faster video game development, creation of special effects featuring humans, as well as novel metaverse user-interaction modes whereby users can control the actions of their or others' avatars via voice or text. + +![](images/3317ca5bee291c7b6c3d5d776e32d9bf3a832d6b06166be90aece8cfd0b7dfe4.jpg) +A person is chopping down a tree with an axe. + +![](images/57caa933c66f5502d33fed499cda001669effa970a7266ab9769aa6b2dc2a21b.jpg) +A person is ice skating. +Figure 1. Samples generated by Make-An-Animation for text conditional motion generation. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. In the top image, for a better visualization, frames are distributed horizontally. + +Text-conditioned human motion generation is challenging for a number of reasons. Firstly, there exists a huge diversity of human motions and text descriptions which describe those motions (i.e., the task is many-to-many distribution matching). Secondly, because motion capture data is expensive to acquire, human motion datasets are limited in scale and diversity. + +Recently, text-to-motion generation has seen rapid improvements in the quality and diversity of poses generated. In particular, diffusion models, which have yielded impressive results in text-conditioned image and video genera + +tion, have proven effective in generating human body poses [35, 16, 38]. However, these models struggle with in-the-wild prompts that are outside of the distribution of motion capture data. + +To address these shortcomings, we present Make-An-Animation, a text-conditioned human motion generation model which learns to map diverse human poses to natural language descriptions through in-the-wild image-text datasets and significantly improves on prior state-of-the-art models which only rely on motion capture data. + +Core to our approach is a large-scale dataset of human poses extracted from image-text datasets. Our key observation is that we should not be limited to learning human motion from motion capture data when we have access to large-scale in-the-wild video and images of human poses. So, to address the limited scale and diversity of motion capture datasets, we extract a large-scale Text Pseudo-Pose (TPP) dataset from image-text datasets filtered for images containing humans. This TPP dataset contains 35M (text, static pose) pairs. + +Make-An-Animation is trained in two stages: (1) We train a text-conditioned static 3D pose generation diffusion model on the TPP dataset. In this stage, Make-An-Animation learns the distribution of human poses and their alignment with text. (2) Then, we extend the pre-trained diffusion model to motion generation via the addition of temporal convolution and attention layers which model the new temporal dimension and train on widely-used motion capture data. In this second stage, the model learns motion, i.e., how to connect poses in a temporally coherent manner. Crucially, it does not have to re-learn the distribution of feasible poses or their alignment with text. + +The Make-An-Animation architecture is a U-Net, similar to recent text-to-video diffusion models. We condition the U-Net on text representations extracted from a language model trained on large-scale language data. We represent human motion as a sequence of 3D SMPL body parameters, with a 6D continuous SMPL representation for 21 body joints and the root orient. We additionally represent the global position per frame via a 3D vector indicating the position in each of the $x, y, z$ dimensions. + +Through human evaluation on a collected set of 400 diverse text prompts, we demonstrate that our method outperforms prior works in terms of generated pose realism and text alignment. + +To summarize, our main contributions are: + +- We present Make-An-Animation - a text-conditioned human motion generation model which improves on prior state-of-the-art models, especially on diverse, in-the-wild text prompts. +- We show, for the first time, how to leverage large-scale image datasets to learn in-the-wild human poses + +for generation. We show through ablations that pretraining on our collected Text Pseudo-Pose dataset significantly improves the generalization to prompts outside the distribution of widely-used motion capture datasets while showing a comparable performance on the mocap test set. + +- We present a U-Net architecture for human motion generation which leverages a language model pretrained on large-scale language data and naturally extends a static text-to-pose generation diffusion model to motion generation via the addition of temporal convolution and attention layers. + +# 2. Related Works + +Human pose and motion generation Prior works in human pose and motion synthesis have explored generative models either unconditionally [36, 40, 25], or conditioned on various input signals such as a prior motion [20, 29], an action class [11, 23, 5], or music [17, 18]. + +Using text descriptions as a guidance in pose and motion synthesis has been a more recent research direction where many existing works use 2D keypoints as pose representations. [41] selects a base pose from 8 clusters based on an input text fed to a GAN model to generate a human image. [39] uses a GAN to generate a set of heatmaps for body keypoints conditioned on the text input. [28] proposes a coarse-to-fine approach where a refinement stage is introduced on top of the initial coarse estimate of the keypoints heatmaps. Different from the above methods, [3] uses SMPL to represent a 3D body pose, generated by an LSTM GAN from a text input. + +Many existing works approach text-to-motion by learning to align text and pose or motion embeddings in the feature space. JL2P [1] proposes to learn the joint embedding of text and pose using an autoencoder with curriculum learning. [7] proposes a two-stream model to encode upper and lower body motions separately. AvatarCLIP [15] uses a pre-trained VPoser model to generate candidate poses, which are then used to optimize a motion VAE. Motion-CLIP [34] trains an auto-encoder while simultaneously reconstructing motion and aligning the motion manifold with CLIP's latent space. TEMOS [24] trains a joint latent space through separate text and motion transformer encoders, allowing non-deterministic motion sampling. T2M [9] also uses a VAE model, but encodes motion as snippets and introduces an extra sampling for motion length conditioned on the input text. + +Leveraging recent advancements in diffusion models, Motion Diffusion Model (MDM) [35], MotionDiffuse [38], and FLAME [16] adopt a diffusion process from text to motion with a transformer, which can significantly improve the diversity of synthesized samples. MDM and MotionDiffuse + +![](images/1d8f6f235d9b2aa47cf74a16dc92d1ce491df36c91bf2b01d8d4a8ebf03bd5ca.jpg) + +![](images/14df4dd0c11dcd1907f5156daa839d7796466c23136fedd1b4f28e772206869a.jpg) + +![](images/f0d48255d8e997126ec0cb6c968e7aae51da4d1d40c6e1ff5beefe480b04ea24.jpg) +Figure 2. Make-An-Animation Model Architecture. Our diffusion model is built on a U-Net architecture inspired by recent image and video generation models. The U-Net consists of a sequence of Residual Blocks with 1x1 2D-convolution layers and Attention Blocks with cross-attention on textual information. To model the temporal dimension, we add 1D temporal convolution layers after each 1x1 2D-convolution, as well as temporal attention layers after each cross-attention layer. These temporal layers (greyed out in the figure) are only added in the motion fine-tuning stage. + +are trained on HumanML3D [9] which partially limits their choice of representation to stick figures for text-to-motion generation, while our curated large-scale dataset provides millions of SMPL pose labels. MDM supports converting poses from stick figures to SMPL bodies only through an optimization SIMPLIFY-X[22] procedure that often results in unrealistic body poses. + +Diffusion generative models Diffusion models are a class a generative model based on the thermodynamic stochastic diffusion process. In the forward diffusion process, a sample is drawn from the data distribution and is gradually noised by a diffusion process. A neural network learns the reverse process to gradually denoise the sample. + +Diffusion models have recently enabled rapid advancements in image generation. [13] first demonstrated diffusion models for unconditional image generation. In comparison to GANs [8] and VAEs, diffusion models have shown superior training stability, avoid mode dropout, and yield stronger performance. Adapting diffusion models for conditional generation, [6] introduced classifier-guided diffusion. More recently, classifier free guidance [14] has been introduced to enable conditioning without the need for a separate classifier. Imagen [30] showed that conditioning on text embeddings extracted from a pre-trained language model enhanced text alignment, and that perfor + +mance improved with text encoder size. Our U-Net architecture shares similarities withImagen. Namely, Make-An-Animation uses the same text encoder, T5-XXL [26], and a similar U-Net architecture. Other improvements have been suggested to improve training stability and performance, such as learning the reverse diffusion variances [21] and v-parameterization [31]. Our method leverages both of these improvements. + +# 3. Text-to-3D Human Motion Generation + +# 3.1. Dataset + +3D Human motion datasets. We use the AMASS dataset of 3D human motions [19] and its textual annotations from the HumanML3D dataset [10]. We borrow the original SMPL annotations from AMASS instead of the processed data from HumanML3D dataset since (1) we found their motion representation contains redundant information, and (2) an extra optimization step would be required to convert their motion representations to the original SMPL format resulting in a degradation in the quality and speed of motion generation in the SMPL format. Similar to HumanML3D, we double the size of the dataset by mirroring the motions and editing the textual description accordingly, resulting in 26850 motion examples in the training set. Additionally, we benefit from the GTA-Human dataset [4] built from an open-world action game providing SMPL annotations over + +![](images/4410f0feb8eabebd5f78beed0648e0da6755be18aa084f368bd1773f3420905a.jpg) +Figure 3. A few examples from our collected TPP dataset. + +![](images/dfdfb1c0f5e6d3f07251f6f6cf241937d78912177e753452a9d88f383b65d1fc.jpg) + +![](images/703290c9fd07ed1eaaed5db90d3dab7ae757ced27c0f9f76c8adf5974b75afb3.jpg) + +![](images/cae0220e04cd165447855d36513db42a2945aa190626041302df17b2831754a4.jpg) + +laid on the virtual humans for 20000 motion samples. This dataset does not have any textual annotation, thus we use it for an unconditional training of our model simultaneous to its text-conditional training. + +Since the existing mocap datasets are limited in the number of samples and their diversity, we also collected a large-scale dataset of in-the-wild human poses from image datasets as follows. + +Large-scale Text Pseudo-Pose (TPP) dataset. Similar to [2], we have collected a dataset containing 35M pairs of human poses and their text descriptions from a few large-scale image-text datasets. We processed all images by running Detectron2 keypoint detector to find images with a single human, then extracted their 3D pseudo-pose SMPL annotations using a pre-trained PyMAF-X model [37]. We used the publicly available captions without any processing. This large-scale data overcomes the limitations of the existing mocap datasets by providing a wide variety of human poses and a huge number of (text, 3D pose) sample pairs despite being noisy. We do not extract any face or hand expressions from the aforementioned datasets. A few examples of the (pseudo-pose, text) pairs are shown in Figure 3. + +# 3.2. Diffusion Models Background + +Diffusion models are a class of generative model that convert Gaussian noise into samples from a learned distribution by iterative denoising. The forward process is a Gaussian noisin processing following a Markove chain, $\{x_{t}\}_{t = 0}^{T}$ where $x_0$ is drawn from the data distribution, in our case a set of 3D SMPL body poses. We can express the forward process as $q(x_{t}|x_{t - 1}) = \mathcal{N}(\sqrt{\alpha_{t}} x_{t - 1},(1 - \alpha_{t})\mathbf{I})$ where $\alpha_{t}\in (0,1)$ . As is standard in training diffusion models, we learn to reverse the forward process by minimizing a noise-prediction loss [13]: + +$$ +\mathcal {L} _ {\text {s i m p l e}} = \mathbb {E} _ {\epsilon \sim \mathcal {N} (0, \mathbf {I}), t \sim U [ 1, T ]} \left[ \| \epsilon_ {t} - \epsilon_ {\theta} (x _ {t}, c, t) \| _ {2} ^ {2} \right] \tag {1} +$$ + +where $c$ is the optional conditioning for the diffusion model, which in our cases are text descriptions. + +In addition to this simple loss, we follow [21, 27] and optimize the hybrid loss, which also uses a loss $L_{vlb}$ that adds a constraint on the estimated variational lower bound (VLB). The $L_{vlb}$ term is applied the same way as in [21]. + +
MethodR-Precision ↑FID ↓Diversity ↑
Real0.797±0.0020.002±0.0029.5±0.65
J2LP[[1]]0.486±.00211.02±.0467.676±.058
MDM[[35]]0.611±.0070.544±.0449.559±.086
T2M[[9]]0.740±.0031.067±.0029.188±.002
MAA0.6755±.0020.7740±0.0078.23±0.064
+ +Table 1. Quantitative results on the HumanML3D test set. We run our evaluation 20 times and $\pm$ indicates the $95\%$ confidence interval. + +We follow [12, 31] and parameterize our models using $v$ -parameterization ( $v_{t} = \alpha_{t}\epsilon - \sigma_{t}x$ ) rather than predicting $\epsilon$ or $x$ . + +# 3.3. Make-An-Animation + +We represent an avatar body pose, $P$ , via 3D SMPL body parameters and an avatar motion as a sequence of body poses for $N$ frames, $[P_1, P_2, \dots, P_N]$ . We use 6D continuous SMPL representation for 21 body joints and the root orient. We additionally represent the global position per frame via a 3D vector indicating the avatar's position in each of the $x, y, z$ dimensions, resulting in each $P_i \in \mathbb{R}^{135}$ . Make-An-Animation is built from three major components: (1) a pre-trained language model trained on a large-scale language data (T5-XXL [26]), (2) a text-to-3D diffusion based pose generation model trained on our collected TPP dataset, and (3) a set of temporal convolution and attention layers extending the static pose generation model to the temporal dimension for motion generation and capturing the dependencies between the frames. + +We follow [12] and use v-prediction parameterization $(v_{t} = \alpha_{t}\epsilon -\sigma_{t}x)$ to train our pose and motion diffusion models for numerical stability. Our denoising model in the above U-Net architecture operates on all motion frames at the same time resulting in a higher temporal coherence in the generated motions compared to the autoregressive frameworks [35] and does not require any specific loss on the motion velocity for a smooth motion synthesis. We also benefit from classifier free guidance [14] at inference by conditioning our model on a null text during training for $10\%$ of the time. + +# 3.3.1 Text-to-3D Pose Generation + +We train a U-Net based diffusion model to generate 3D SMPL pose parameters conditioning on text embeddings from a large frozen language model [26]. Inspired by the image and video generation models [32], we reshape the pose inputs to $B \times C \times 1 \times 1$ with $B$ and $C$ indicating batch size and channel dimension of 135, respectively. Our U-Net model is built from a sequence of (1) Residual blocks with 1x1 2D-convolution layers conditioned on the diffu + +![](images/9f38604501a931b869b823c882a6b8880d19bf2531644212a9f1d40b01b75c3e.jpg) +(a) Which motion corresponds better with the textual description? + +![](images/7c1d16a5fe0d6266594b338413ad1fc8fd92871303265f7e08511d782cf62e6a.jpg) +(b) Which motion is more realistic? +Figure 4. Human Evaluation. Here we compare each baseline against our model, MAA, in terms of text alignment and motion realism. The results are reported as the percentage of the majority vote raters that preferred our method to each baseline on our curated 400 prompts set. + +![](images/817dea198838115243d293082e25f811218002fb5459034c461035860edba322.jpg) +Figure 5. Ablation Study. Here we compare each ablated model against our model, MAA, in terms text alignment and motion realism. The results are reported as the percentage of the majority vote raters that preferred our method to each baseline on our curated 400 prompts set. + +sion time-step embedding and text embedding, and (2) Attention Blocks attending to the textual information and the diffusion time-step. We train this network on our large-scale TPP dataset where we set translation parameters to zero in all training examples, i.e., human at the center of the scene. + +# 3.3.2 Temporal and Attention Layers + +In order to expand the aforementioned pose generation model to learn the temporal dimension for motion generation, we modify the convolutional and attention layers of the U-Net as follows. + +We reshape the input motion sequence to a tensor of shape $B \times C \times N \times 1 \times 1$ , where $C$ is the length of the pose representation and $N$ is the number of frames. Inspired by [32, 12], we stack a 1D temporal convolution layer following each 1x1 2D-convolution. This allows us to train the new 1D temporal layers from scratch while loading the pre-trained convolution weights from the pose generation model. We set the kernel size of these temporal convolution + +layers to 3 opposed to the unit kernel size of the 2D convolutions. We apply a similar dimension decomposition strategy to the attention layers, where we stack a newly initialized temporal attention layer to each pre-trained attention block from the pose generation network. For the temporal attention layers we utilize a Rotary Position Embedding [33]. + +# 4. Experiments + +We compare the performance of our motion generation model with the existing state-of-the-art text-to-human-motion generation models through human evaluation on 400 crowd-sourced prompts and automatic metrics on the HumanML3D test set. + +# 4.1. Automatic Metrics + +We perform an automatic evaluation on the HumanML3D test set in terms of Fréchet Distance (FID), R-Precision and Diversity scores. FID measures both diversity and quality of the samples comparing its distribution with the ground truth test set while R-Precision measures faithfulness between each generated motion and its input prompt. Diversity measures the variance of the generated motions across all descriptions. To compute the above scores, a motion encoder was jointly trained with a text encoder via a contrastive loss by [9]. We use the same encoder to extract text and motion embeddings. Since this model has been trained and optimized on the 263-dimensional pose representation vector, we transform both the ground-truth SMPL data and our generated samples similarly following the transformations provided by [11] before computing the above metrics. We upsample our generations to 196 frames and keep that fixed for the ground truth samples and our outputs while computing the above metrics. Opposed to our baselines, we have not optimized our model on the 263-dimensional motion representation, but achieve a comparable performance in all metrics as reported in Table 1. + +# 4.2. Human Evaluation + +To evaluate the generalization ability of our model in synthesizing more challenging human poses and motions, we collected an evaluation set from Amazon Mechanical Turk (AMT) that consists of 400 prompts. We asked annotators for prompts that described an action along with some context of the scene. We filtered out prompts based on ethical concerns to remove any references to children or NSFW content. These prompts were selected without generating any poses or images for them, and were kept fixed for all of our evaluations. This test set is released here1. We generated animated poses from all models with no translation to measure the correctness and quality of the body pose and motion. We show raters a text description and the corresponding rendered avatars from two models and ask them which output better matches the input text. For each comparison, we use the majority vote from 7 different annotators on 400 prompts as the final result, reported in Figure 4. This study confirms the superiority of our model and the impact of our large-scale TPP dataset in human motion generation and overcoming the limitations of the mocap datasets. A few motion samples generated by our model are shown in Figure 8 and more are included on our webpage1. + +# 4.3. Ablation Studies + +To disentangle and study the impact of our U-Net architecture versus the impact on our TPP dataset on our results, we implemented and trained an alternative diffusion model as a decoder-only transformer with a causal attention mask to generate 3D pose representations from text. This model operates on a sequence of tokenized captions and their text embeddings, the diffusion time-step embedding, the noised body pose and root orient representations, and two final pose and orientation queries to predict the unnoised pose and root orientation, respectively. We pre-trained this model on our TPP dataset, then expanded the model for motion synthesis via adding three additional tokens per frame for pose, root orient, and translation paramters. We trained this model on the mocap datasets described in Sec 3.1 and compared its performance with our U-Net model via Amazon Mechanical Turk. As a result, $58\%$ of the raters preferred the generations from our U-Net architecture. This experiment confirms the superiority of the U-Net model versus its auto-regressive alternatives. We also ablated the impact of temporal attention modules on the final quality of the samples resulting in $54\%$ of the users preferring samples from a U-Net with temporal attention. + +Training with the GTA data unconditionally made the convergence of the model faster although it didn't impact the samples' quality after convergence. + +Additionally, we experimented with training our U-Net + +![](images/99d8ae57a92f5c1b873b17f8455473633da3c82464e90b08ee1bce94f8b55f27.jpg) +A person is playing football in playground + +![](images/770a6c7a92c302d46258861724fc1dbada72027158d24c0c39cf24683b5f9c21.jpg) + +![](images/5550d41fb7701fde2559aaee472deda3fa78cda78910aef9649ec4e0fda5bfeb.jpg) + +![](images/b147549a7d3b0619e62349fce672b863c3c8086476f733cf4d2d4bf1f3e95ee9.jpg) +A person dancing in the street + +![](images/e6d1195e1ea003346f3a827ff592fa77cecdffbceb1559cf6afe573801f29ea8.jpg) + +![](images/b8765ec569532be7bdfd53cbc8ed37a49db2993571219f219a488acca0877fea.jpg) +Figure 6. Diverse samples generated by Make-An-Animation for text conditional motion generation. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. For a better visualization, frames are down-sampled along the temporal dimension and distributed horizontally. + +![](images/ca571b6c0bd8a486c30d92d6e17e4ab78f20054460a9aaac50b42d15fa1eaeff.jpg) +MAA Generations +A person wrestles a bear in the forest + +![](images/84f7f6cd8a5319c361eed8fe9ffd976008a42a8d528300270e0e335e00be6b35.jpg) +Nearest Neighbour Example +a person puts both arms into the air + +![](images/b421531488792713fad60a3b93fbaff18d581ca8fe2f06fadf104a235358bebc.jpg) +A person is practicing the flute + +![](images/d981404c575242b5fd968461147e9fcfaf3b16f747c2d4f2082bf32689ca74b7.jpg) +a person clapping with his hands + +![](images/ecfe3bf181726948b0aa5d32657a80aa31ab14ac3ce87253b3ff91a8b0575518.jpg) +A person is sawing a branch off of a tree +Figure 7. Left: samples generated by Make-An-Animation for text conditional motion generation. Right: The nearest neighbor example for each of the generated samples found from the mocap training set based on motion and text clip similarity scores. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. For a better visualization, frames are distributed horizontally. + +![](images/b9f83de2b62046177c659e6d7cc6d30e46f2576fe90dd30f6d2b196df5bf45db.jpg) +a man raises his hands to his chest, claps them together, then lowers them back to his sides + +model on the mocap training set from scratch and without pre-training. However, we observed stability and convergence issues in this setting even with various learning rates and warming up updates. The pre-training stage on the large-scale dataset was therefore a stable solution resulting in high quality motion samples in the end. All ablation results are summarized in Figure 5. + +# 4.4. Qualitative Studies + +In Figure 7, we visualize the generalization capability of our model in synthesizing novel motions. We investigate the existence of similar prompts or motions in the train + +ing data for each synthesized motion via a nearest neighbor search. We extract the motion embedding and text embedding for each sample in our test set of prompts as well as our mocap training data using a pre-trained motionCLIP model [34, 16] that has learned a joint motion and language embedding space. For each synthesized motion, we find the top 6 motions and prompts from the training data with the highest cosine similarity scores. As shown in the figure, our model has generalized to new motions that did not exist in the training data. In addition, Figure 6 illustrates multiple diverse motions generated by our model for different text prompt. + +![](images/bfa30e679e5c72d388a9e401992ec85602fa91aafd101aea0de0bfbd322f6648.jpg) +A person is doing a handstand on a cactus + +![](images/ba5d9b87d012d84495342e7dfc2e0c1a4705f2f8fe094567fea5724c6828f1af.jpg) +A person kicks a soccer ball + +![](images/82f978aeb2350eb6eea71114941428390649b20eb978ac7c916327d4436546c5.jpg) +A person is rowing a small dingy in a river + +![](images/f04008afad21d8211f0c71bef053c4cacdf8e04167f8b9594ebc4f05b2dc14d8.jpg) +A person is playing tennis at the Recreation Center + +![](images/5dc2504192f488274b3f3e703945552b165baf030730221d0a6297a57d25f19a.jpg) +A volleyball player bumps a ball up + +![](images/4d044153d9b28e995fec65730adaa4a28808b80184f62ae4a8ce2ebfc54b7270.jpg) +A photographer is looking through the camera + +![](images/f4e92455eb3fbdd47409027ff835b39d5151e7be18247c48047b98e0b7c2d3ef.jpg) +A person is shoveling the driveway after a blizzard + +![](images/5c21ffc224a3bc82285b3aae5aff2d43ff2727d36f32df654872bfcf8c4162e9.jpg) +A person is sitting down on the ground +Figure 8. Samples generated by Make-An-Animation for text conditional motion generation. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. For a better visualization, frames are distributed horizontally. + +# 5. Conclusion + +Current text-to-motion models are hindered by relatively small-scale motion capture datasets, as evident by their poor performance on more diverse, in-the-wild prompts. + +Motivated by this shortcoming, we present Make-An-Animation, a human motion generation model trained on a collection of large-scale static pseudo-pose and motion capture data. As we demonstrate through our ablations and human studies comparing to prior works, pre-training on the + +large-scale TPP dataset significantly improves performance on captions outside of the distribution of motion capture data. Furthermore, our novel U-Net architecture enables a seamless transition between static pose pre-training and dynamic pose (i.e., motion) fine-tuning. Altogether, this work paves the way to leverage large-scale image and video datasets for learning generation of human 3D pose parameters. + +# References + +[1] Chaitanya Ahuja and Louis-Philippe Morency. Language2pose: Natural language grounded pose forecasting. IEEE International Conference on 3D Vision (3DV), pages 719-728, 2019. +[2] Samaneh Azadi, Thomas Hayes, Akbar Shah, Guan Pang, Devi Parikh, and Sonal Gupta. Text-conditional contextualized avatars for zero-shot personalization. arXiv preprint arXiv:2304.07410, 2023. +[3] Rania Briq, Pratika Kochar, and Juergen Gall. Towards better adversarial synthesis of human images from text. arXiv preprint arXiv:2107.01869, 2021. +[4] Zhongang Cai, Mingyuan Zhang, Jiawei Ren, Chen Wei, Daxuan Ren, Zhengyu Lin, Haiyu Zhao, Lei Yang, and Zwei Liu. Playing for 3d human recovery. arXiv preprint arXiv:2110.07588, 2021. +[5] Pablo Cervantes, Yusuke Sekikawa, Ikuro Sato, and Koichi Shinoda. Implicit neural representations for variable length human motion generation. European Conference on Computer Vision (ECCV), 2022. +[6] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Advances in Neural Information Processing Systems (NeurIPS), 34, 2021. +[7] Anindita Ghosh, Noshaba Cheema, Cennet Oguz, Christian Theobalt, and Philipp Slusallek. Synthesis of compositional animations from textual descriptions. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 1396-1406, October 2021. +[8] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In Advances in Neural Information Processing Systems, 2014. +[9] Chuan Guo, Shihao Zou, Xinxin Zuo, Sen Wang, Wei Ji, Xingyu Li, and Li Cheng. Generating diverse and natural 3d human motions from text. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 5152-5161, June 2022. +[10] Chuan Guo, Shihao Zou, Xinxin Zuo, Sen Wang, Wei Ji, Xingyu Li, and Li Cheng. Generating diverse and natural 3d human motions from text. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 5152-5161, June 2022. +[11] Chuan Guo, Xinxin Zuo, Sen Wang, Shihao Zou, Qingyao Sun, Annan Deng, Minglun Gong, and Li Cheng. Action2motion: Conditioned generation of 3d human motions. Proceedings of the 28th ACM International Conference on Multimedia, pages 2021-2029, 2020. +[12] Jonathan Ho, William Chan, Chitwan Saharia, Jay Whang, Ruiqi Gao, Alexey Gritsenko, Diederik P Kingma, Ben Poole, Mohammad Norouzi, David J Fleet, et al. Imagen video: High definition video generation with diffusion models. arXiv preprint arXiv:2210.02303, 2022. +[13] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Advances in Neural Information Processing Systems (NeurIPS), 33, 2020. +[14] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. arXiv preprint arXiv:2207.12598, 2022. + +[15] Fangzhou Hong, Mingyuan Zhang, Liang Pan, Zhongang Cai, Lei Yang, and Ziwei Liu. Avatarclip: Zero-shot text-driven generation and animation of 3d avatars. ACM Transactions on Graphics (TOG), 41(4):1-19, 2022. +[16] Jihoon Kim, Jiseob Kim, and Sungjoon Choi. Flame: Freeform language-based motion synthesis & editing. arXiv preprint arXiv:2209.00349, 2022. +[17] Hsin-Ying Lee, Xiaodong Yang, Ming-Yu Liu, Ting-Chun Wang, Yu-Ding Lu, Ming-Hsuan Yang, and Jan Kautz. Dancing to music. Advances in Neural Information Processing Systems (NeurIPS), 32, 2019. +[18] Ruilong Li, Shan Yang, David A. Ross, and Angjoo Kanazawa. Ai choreographer: Music conditioned 3d dance generation with aist++. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), 2021. +[19] Naureen Mahmood, Nima Ghorbani, Nikolaus F. Troje, Gerard Pons-Moll, and Michael J. Black. AMASS: Archive of motion capture as surface shapes. In International Conference on Computer Vision, pages 5442-5451, Oct. 2019. +[20] Julieta Martinez, Michael J. Black, and Javier Romero. On human motion prediction using recurrent neural networks. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2017. +[21] Alexander Quinn Nichol and Prafulla Dhariwal. Improved denoising diffusion probabilistic models. In International Conference on Machine Learning, pages 8162-8171. PMLR, 2021. +[22] Georgios Pavlakos, Vasileios Choutas, Nima Ghorbani, Timo Bolkart, Ahmed A. A. Osman, Dimitrios Tzionas, and Michael J. Black. Expressive body capture: 3d hands, face, and body from a single image. In Conference on Computer Vision and Pattern Recognition (CVPR), 2019. +[23] Mathis Petrovich, Michael J. Black, and Gül Varol. Action-conditioned 3D human motion synthesis with transformer VAE. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 10985-10995, October 2021. +[24] Mathis Petrovich, Michael J. Black, and Gül Varol. Temos: Generating diverse human motions from textual descriptions. European Conference on Computer Vision (ECCV), 2022. +[25] Sigal Raab, Inbal Leibovitch, Peizhuo Li, Kfir Aberman, Olga Sorkine-Hornung, and Daniel Cohen-Or. Modi: Unconditional motion synthesis from diverse data. arXiv preprint arXiv:2206.08010, 2022. +[26] Colin Raffel, Noam Shazeer, Adam Roberts, Katherine Lee, Sharan Narang, Michael Matena, Yanqi Zhou, Wei Li, and Peter J. Liu. Exploring the limits of transfer learning with a unified text-to-text transformer. JMLR, 2020. +[27] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022. +[28] Prasun Roy, Subhankar Ghosh, Saumik Bhattacharya, Umapada Pal, and Michael Blumenstein. Tips: Text-induced pose synthesis. European Conference on Computer Vision (ECCV), 2022. + +[29] Alejandro Hernandez Ruiz, Juergen Gall, and Francesc Moreno-Noguer. Human motion prediction via spatiotemporal inpainting. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), 2019. +[30] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S. Sara Mahdavi, Rapha Gontijo Lopes, Tim Salimans, Jonathan Ho, David J Fleet, and Mohammad Norouzi. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022. +[31] T. Salimans and J Ho. Progressive distillation for fast sampling of diffusion models. International Conference on Learning Representations, 2022. +[32] Uriel Singer, Adam Polyak, Thomas Hayes, Xi Yin, Jie An, Songyang Zhang, Qiyuan Hu, Harry Yang, Oron Ashual, Oran Gafni, et al. Make-a-video: Text-to-video generation without text-video data. arXiv preprint arXiv:2209.14792, 2022. +[33] Jianlin Su, Yu Lu, Shengfeng Pan, Ahmed Murtadha, Bo Wen, and Yunfeng Liu. Roformer: Enhanced transformer with rotary position embedding. arXiv preprint arXiv:2104.09864, 2021. +[34] Guy Tevet, Brian Gordon, Amir Hertz, Amit H. Bermano, and Daniel Cohen-Or. Motionclip: Exposing human motion generation to clip space. European Conference on Computer Vision (ECCV), 2022. +[35] Guy Tevet, Sigal Raab, Brian Gordon, Yonatan Shafir, Amit H Bermano, and Daniel Cohen-Or. Human motion diffusion model. arXiv preprint arXiv:2209.14916, 2022. +[36] Sijie Yan, Zhizhong Li, Yuanjun Xiong, Huahan Yan, and Dahua Lin. Convolutional sequence generation for skeleton-based action synthesis. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 4393-4401, 2019. +[37] Hongwen Zhang, Yating Tian, Yuxiang Zhang, Mengcheng Li, Liang An, Zhenan Sun, and Yebin Liu. Pymaf-x: Towards well-aligned full-body model regression from monocular images. arXiv preprint arXiv:2207.06400, 2022. +[38] Mingyuan Zhang, Zhongang Cai, Liang Pan, Fangzhou Hong, Xinying Guo, Lei Yang, and Ziwei Liu. Motiondiffuse: Text-driven human motion generation with diffusion model. arXiv preprint arXiv:2208.15001, 2022. +[39] Yifei Zhang, Rania Briq, Julian Tanke, and Juergen Gall. Adversarial synthesis of human pose from text. 42nd DAGM German Conference of Pattern Recognition, pages 145-158, 2021. +[40] Rui Zhao, Hui Su, and Qiang Ji. Bayesian adversarial human motion synthesis. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 6224-6233, 2020. +[41] Xingran Zhou, Siyu Huang, Bin Li, Yingming Li, Jiachen Li, and Zhongfei Zhang. Text guided person image synthesis. Proceedings IEEE Conf. on Computer Vision and Pattern Recognition (CVPR), 2019. \ No newline at end of file diff --git a/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/images.zip b/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..e38b9a73ad227c512d414772f97d153544a8410d --- /dev/null +++ b/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:36d888b1bc8ce8b9afb4d32509937d3b7a8e2a3cc44342dad8b58a058bb0473c +size 530056 diff --git a/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/layout.json b/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..a81e13ed5693b8360f1eeac8a8a3218730432c21 --- /dev/null +++ b/2023/Make-An-Animation_ Large-Scale Text-conditional 3D Human Motion Generation/layout.json @@ -0,0 +1,7453 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 111, + 103, + 483, + 138 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 103, + 483, + 138 + ], + "spans": [ + { + "bbox": [ + 111, + 103, + 483, + 138 + ], + "type": "text", + "content": "Make-An-Animation: Large-Scale Text-conditional 3D Human Motion Generation" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 78, + 161, + 157, + 175 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 78, + 161, + 157, + 175 + ], + "spans": [ + { + "bbox": [ + 78, + 161, + 157, + 175 + ], + "type": "text", + "content": "Samaneh Azadi" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 183, + 161, + 242, + 175 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 183, + 161, + 242, + 175 + ], + "spans": [ + { + "bbox": [ + 183, + 161, + 242, + 175 + ], + "type": "text", + "content": "Akbar Shah" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 268, + 161, + 341, + 188 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 268, + 161, + 341, + 188 + ], + "spans": [ + { + "bbox": [ + 268, + 161, + 341, + 188 + ], + "type": "text", + "content": "Thomas Hayes Meta AI" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 367, + 161, + 427, + 175 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 367, + 161, + 427, + 175 + ], + "spans": [ + { + "bbox": [ + 367, + 161, + 427, + 175 + ], + "type": "text", + "content": "Devi Parikh" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 452, + 161, + 515, + 176 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 452, + 161, + 515, + 176 + ], + "spans": [ + { + "bbox": [ + 452, + 161, + 515, + 176 + ], + "type": "text", + "content": "Sonal Gupta" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 143, + 217, + 192, + 229 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 217, + 192, + 229 + ], + "spans": [ + { + "bbox": [ + 143, + 217, + 192, + 229 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 242, + 290, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 242, + 290, + 529 + ], + "spans": [ + { + "bbox": [ + 47, + 242, + 290, + 529 + ], + "type": "text", + "content": "Text-guided human motion generation has drawn significant interest because of its impactful applications spanning animation and robotics. Recently, application of diffusion models for motion generation has enabled improvements in the quality of generated motions. However, existing approaches are limited by their reliance on relatively small-scale motion capture data, leading to poor performance on more diverse, in-the-wild prompts. In this paper, we introduce Make-An-Animation, a text-conditioned human motion generation model which learns more diverse poses and prompts from large-scale image-text datasets, enabling significant improvement in performance over prior works. Make-An-Animation is trained in two stages. First, we train on a curated large-scale dataset of (text, static pseudo-pose) pairs extracted from image-text datasets. Second, we fine-tune on motion capture data, adding additional layers to model the temporal dimension. Unlike prior diffusion models for motion generation, Make-An-Animation uses a U-Net architecture similar to recent text-to-video generation models. Human evaluation of motion realism and alignment with input text shows that our model reaches state-of-the-art performance on text-to-motion generation. Generated samples can be viewed at https://azadis.github.io/make-an-animation." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 549, + 128, + 562 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 549, + 128, + 562 + ], + "spans": [ + { + "bbox": [ + 47, + 549, + 128, + 562 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 570, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 288, + 713 + ], + "type": "text", + "content": "As the world shifts towards virtual spaces, and as embodied agents become more capable, it will be increasingly important to be able to generate plausible human motion. Speech or text are perhaps the most natural ways to prompt generative models, which is one reason behind the explosion in text-to-x generation research. Human motion generation from text has diverse applications both in virtual and real worlds. For instance, it enables control of robots with speech, faster video game development, creation of special effects featuring humans, as well as novel metaverse user-interaction modes whereby users can control the actions of their or others' avatars via voice or text." + } + ] + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 307, + 238, + 552, + 338 + ], + "blocks": [ + { + "bbox": [ + 307, + 238, + 552, + 338 + ], + "lines": [ + { + "bbox": [ + 307, + 238, + 552, + 338 + ], + "spans": [ + { + "bbox": [ + 307, + 238, + 552, + 338 + ], + "type": "image", + "image_path": "3317ca5bee291c7b6c3d5d776e32d9bf3a832d6b06166be90aece8cfd0b7dfe4.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 364, + 342, + 512, + 352 + ], + "lines": [ + { + "bbox": [ + 364, + 342, + 512, + 352 + ], + "spans": [ + { + "bbox": [ + 364, + 342, + 512, + 352 + ], + "type": "text", + "content": "A person is chopping down a tree with an axe." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 307, + 364, + 552, + 473 + ], + "blocks": [ + { + "bbox": [ + 307, + 364, + 552, + 473 + ], + "lines": [ + { + "bbox": [ + 307, + 364, + 552, + 473 + ], + "spans": [ + { + "bbox": [ + 307, + 364, + 552, + 473 + ], + "type": "image", + "image_path": "57caa933c66f5502d33fed499cda001669effa970a7266ab9769aa6b2dc2a21b.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 400, + 478, + 473, + 487 + ], + "lines": [ + { + "bbox": [ + 400, + 478, + 473, + 487 + ], + "spans": [ + { + "bbox": [ + 400, + 478, + 473, + 487 + ], + "type": "text", + "content": "A person is ice skating." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 305, + 500, + 547, + 555 + ], + "lines": [ + { + "bbox": [ + 305, + 500, + 547, + 555 + ], + "spans": [ + { + "bbox": [ + 305, + 500, + 547, + 555 + ], + "type": "text", + "content": "Figure 1. Samples generated by Make-An-Animation for text conditional motion generation. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. In the top image, for a better visualization, frames are distributed horizontally." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 579, + 547, + 663 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 579, + 547, + 663 + ], + "spans": [ + { + "bbox": [ + 304, + 579, + 547, + 663 + ], + "type": "text", + "content": "Text-conditioned human motion generation is challenging for a number of reasons. Firstly, there exists a huge diversity of human motions and text descriptions which describe those motions (i.e., the task is many-to-many distribution matching). Secondly, because motion capture data is expensive to acquire, human motion datasets are limited in scale and diversity." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "content": "Recently, text-to-motion generation has seen rapid improvements in the quality and diversity of poses generated. In particular, diffusion models, which have yielded impressive results in text-conditioned image and video genera" + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "15039" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": "tion, have proven effective in generating human body poses [35, 16, 38]. However, these models struggle with in-the-wild prompts that are outside of the distribution of motion capture data." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 120, + 287, + 192 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 120, + 287, + 192 + ], + "spans": [ + { + "bbox": [ + 46, + 120, + 287, + 192 + ], + "type": "text", + "content": "To address these shortcomings, we present Make-An-Animation, a text-conditioned human motion generation model which learns to map diverse human poses to natural language descriptions through in-the-wild image-text datasets and significantly improves on prior state-of-the-art models which only rely on motion capture data." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 192, + 286, + 312 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 192, + 286, + 312 + ], + "spans": [ + { + "bbox": [ + 46, + 192, + 286, + 312 + ], + "type": "text", + "content": "Core to our approach is a large-scale dataset of human poses extracted from image-text datasets. Our key observation is that we should not be limited to learning human motion from motion capture data when we have access to large-scale in-the-wild video and images of human poses. So, to address the limited scale and diversity of motion capture datasets, we extract a large-scale Text Pseudo-Pose (TPP) dataset from image-text datasets filtered for images containing humans. This TPP dataset contains 35M (text, static pose) pairs." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 312, + 286, + 455 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 312, + 286, + 455 + ], + "spans": [ + { + "bbox": [ + 46, + 312, + 286, + 455 + ], + "type": "text", + "content": "Make-An-Animation is trained in two stages: (1) We train a text-conditioned static 3D pose generation diffusion model on the TPP dataset. In this stage, Make-An-Animation learns the distribution of human poses and their alignment with text. (2) Then, we extend the pre-trained diffusion model to motion generation via the addition of temporal convolution and attention layers which model the new temporal dimension and train on widely-used motion capture data. In this second stage, the model learns motion, i.e., how to connect poses in a temporally coherent manner. Crucially, it does not have to re-learn the distribution of feasible poses or their alignment with text." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 456, + 286, + 563 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 456, + 286, + 563 + ], + "spans": [ + { + "bbox": [ + 46, + 456, + 286, + 563 + ], + "type": "text", + "content": "The Make-An-Animation architecture is a U-Net, similar to recent text-to-video diffusion models. We condition the U-Net on text representations extracted from a language model trained on large-scale language data. We represent human motion as a sequence of 3D SMPL body parameters, with a 6D continuous SMPL representation for 21 body joints and the root orient. We additionally represent the global position per frame via a 3D vector indicating the position in each of the " + }, + { + "bbox": [ + 46, + 456, + 286, + 563 + ], + "type": "inline_equation", + "content": "x, y, z" + }, + { + "bbox": [ + 46, + 456, + 286, + 563 + ], + "type": "text", + "content": " dimensions." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 563, + 286, + 611 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 563, + 286, + 611 + ], + "spans": [ + { + "bbox": [ + 46, + 563, + 286, + 611 + ], + "type": "text", + "content": "Through human evaluation on a collected set of 400 diverse text prompts, we demonstrate that our method outperforms prior works in terms of generated pose realism and text alignment." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 59, + 612, + 232, + 623 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 612, + 232, + 623 + ], + "spans": [ + { + "bbox": [ + 59, + 612, + 232, + 623 + ], + "type": "text", + "content": "To summarize, our main contributions are:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 58, + 632, + 286, + 713 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 58, + 632, + 286, + 680 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 632, + 286, + 680 + ], + "spans": [ + { + "bbox": [ + 58, + 632, + 286, + 680 + ], + "type": "text", + "content": "- We present Make-An-Animation - a text-conditioned human motion generation model which improves on prior state-of-the-art models, especially on diverse, in-the-wild text prompts." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 58, + 689, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 689, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 58, + 689, + 286, + 713 + ], + "type": "text", + "content": "- We show, for the first time, how to leverage large-scale image datasets to learn in-the-wild human poses" + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 324, + 72, + 545, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 324, + 72, + 545, + 144 + ], + "spans": [ + { + "bbox": [ + 324, + 72, + 545, + 144 + ], + "type": "text", + "content": "for generation. We show through ablations that pretraining on our collected Text Pseudo-Pose dataset significantly improves the generalization to prompts outside the distribution of widely-used motion capture datasets while showing a comparable performance on the mocap test set." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 317, + 151, + 545, + 223 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 151, + 545, + 223 + ], + "spans": [ + { + "bbox": [ + 317, + 151, + 545, + 223 + ], + "type": "text", + "content": "- We present a U-Net architecture for human motion generation which leverages a language model pretrained on large-scale language data and naturally extends a static text-to-pose generation diffusion model to motion generation via the addition of temporal convolution and attention layers." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 239, + 397, + 251 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 239, + 397, + 251 + ], + "spans": [ + { + "bbox": [ + 306, + 239, + 397, + 251 + ], + "type": "text", + "content": "2. Related Works" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 258, + 545, + 319 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 258, + 545, + 319 + ], + "spans": [ + { + "bbox": [ + 305, + 258, + 545, + 319 + ], + "type": "text", + "content": "Human pose and motion generation Prior works in human pose and motion synthesis have explored generative models either unconditionally [36, 40, 25], or conditioned on various input signals such as a prior motion [20, 29], an action class [11, 23, 5], or music [17, 18]." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 319, + 545, + 461 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 319, + 545, + 461 + ], + "spans": [ + { + "bbox": [ + 304, + 319, + 545, + 461 + ], + "type": "text", + "content": "Using text descriptions as a guidance in pose and motion synthesis has been a more recent research direction where many existing works use 2D keypoints as pose representations. [41] selects a base pose from 8 clusters based on an input text fed to a GAN model to generate a human image. [39] uses a GAN to generate a set of heatmaps for body keypoints conditioned on the text input. [28] proposes a coarse-to-fine approach where a refinement stage is introduced on top of the initial coarse estimate of the keypoints heatmaps. Different from the above methods, [3] uses SMPL to represent a 3D body pose, generated by an LSTM GAN from a text input." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 463, + 545, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 463, + 545, + 653 + ], + "spans": [ + { + "bbox": [ + 304, + 463, + 545, + 653 + ], + "type": "text", + "content": "Many existing works approach text-to-motion by learning to align text and pose or motion embeddings in the feature space. JL2P [1] proposes to learn the joint embedding of text and pose using an autoencoder with curriculum learning. [7] proposes a two-stream model to encode upper and lower body motions separately. AvatarCLIP [15] uses a pre-trained VPoser model to generate candidate poses, which are then used to optimize a motion VAE. Motion-CLIP [34] trains an auto-encoder while simultaneously reconstructing motion and aligning the motion manifold with CLIP's latent space. TEMOS [24] trains a joint latent space through separate text and motion transformer encoders, allowing non-deterministic motion sampling. T2M [9] also uses a VAE model, but encodes motion as snippets and introduces an extra sampling for motion length conditioned on the input text." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": "Leveraging recent advancements in diffusion models, Motion Diffusion Model (MDM) [35], MotionDiffuse [38], and FLAME [16] adopt a diffusion process from text to motion with a transformer, which can significantly improve the diversity of synthesized samples. MDM and MotionDiffuse" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "15040" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 70, + 236, + 304 + ], + "blocks": [ + { + "bbox": [ + 53, + 70, + 236, + 304 + ], + "lines": [ + { + "bbox": [ + 53, + 70, + 236, + 304 + ], + "spans": [ + { + "bbox": [ + 53, + 70, + 236, + 304 + ], + "type": "image", + "image_path": "1d8f6f235d9b2aa47cf74a16dc92d1ce491df36c91bf2b01d8d4a8ebf03bd5ca.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 246, + 70, + 387, + 300 + ], + "blocks": [ + { + "bbox": [ + 246, + 70, + 387, + 300 + ], + "lines": [ + { + "bbox": [ + 246, + 70, + 387, + 300 + ], + "spans": [ + { + "bbox": [ + 246, + 70, + 387, + 300 + ], + "type": "image", + "image_path": "14df4dd0c11dcd1907f5156daa839d7796466c23136fedd1b4f28e772206869a.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 394, + 71, + 544, + 313 + ], + "blocks": [ + { + "bbox": [ + 394, + 71, + 544, + 313 + ], + "lines": [ + { + "bbox": [ + 394, + 71, + 544, + 313 + ], + "spans": [ + { + "bbox": [ + 394, + 71, + 544, + 313 + ], + "type": "image", + "image_path": "f0d48255d8e997126ec0cb6c968e7aae51da4d1d40c6e1ff5beefe480b04ea24.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 316, + 547, + 373 + ], + "lines": [ + { + "bbox": [ + 46, + 316, + 547, + 373 + ], + "spans": [ + { + "bbox": [ + 46, + 316, + 547, + 373 + ], + "type": "text", + "content": "Figure 2. Make-An-Animation Model Architecture. Our diffusion model is built on a U-Net architecture inspired by recent image and video generation models. The U-Net consists of a sequence of Residual Blocks with 1x1 2D-convolution layers and Attention Blocks with cross-attention on textual information. To model the temporal dimension, we add 1D temporal convolution layers after each 1x1 2D-convolution, as well as temporal attention layers after each cross-attention layer. These temporal layers (greyed out in the figure) are only added in the motion fine-tuning stage." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 391, + 288, + 477 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 391, + 288, + 477 + ], + "spans": [ + { + "bbox": [ + 46, + 391, + 288, + 477 + ], + "type": "text", + "content": "are trained on HumanML3D [9] which partially limits their choice of representation to stick figures for text-to-motion generation, while our curated large-scale dataset provides millions of SMPL pose labels. MDM supports converting poses from stick figures to SMPL bodies only through an optimization SIMPLIFY-X[22] procedure that often results in unrealistic body poses." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 497, + 287, + 569 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 497, + 287, + 569 + ], + "spans": [ + { + "bbox": [ + 46, + 497, + 287, + 569 + ], + "type": "text", + "content": "Diffusion generative models Diffusion models are a class a generative model based on the thermodynamic stochastic diffusion process. In the forward diffusion process, a sample is drawn from the data distribution and is gradually noised by a diffusion process. A neural network learns the reverse process to gradually denoise the sample." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 570, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 288, + 715 + ], + "type": "text", + "content": "Diffusion models have recently enabled rapid advancements in image generation. [13] first demonstrated diffusion models for unconditional image generation. In comparison to GANs [8] and VAEs, diffusion models have shown superior training stability, avoid mode dropout, and yield stronger performance. Adapting diffusion models for conditional generation, [6] introduced classifier-guided diffusion. More recently, classifier free guidance [14] has been introduced to enable conditioning without the need for a separate classifier. Imagen [30] showed that conditioning on text embeddings extracted from a pre-trained language model enhanced text alignment, and that perfor" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 391, + 547, + 488 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 391, + 547, + 488 + ], + "spans": [ + { + "bbox": [ + 304, + 391, + 547, + 488 + ], + "type": "text", + "content": "mance improved with text encoder size. Our U-Net architecture shares similarities withImagen. Namely, Make-An-Animation uses the same text encoder, T5-XXL [26], and a similar U-Net architecture. Other improvements have been suggested to improve training stability and performance, such as learning the reverse diffusion variances [21] and v-parameterization [31]. Our method leverages both of these improvements." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 496, + 519, + 509 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 496, + 519, + 509 + ], + "spans": [ + { + "bbox": [ + 305, + 496, + 519, + 509 + ], + "type": "text", + "content": "3. Text-to-3D Human Motion Generation" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 515, + 365, + 528 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 515, + 365, + 528 + ], + "spans": [ + { + "bbox": [ + 306, + 515, + 365, + 528 + ], + "type": "text", + "content": "3.1. Dataset" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 533, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 547, + 715 + ], + "type": "text", + "content": "3D Human motion datasets. We use the AMASS dataset of 3D human motions [19] and its textual annotations from the HumanML3D dataset [10]. We borrow the original SMPL annotations from AMASS instead of the processed data from HumanML3D dataset since (1) we found their motion representation contains redundant information, and (2) an extra optimization step would be required to convert their motion representations to the original SMPL format resulting in a degradation in the quality and speed of motion generation in the SMPL format. Similar to HumanML3D, we double the size of the dataset by mirroring the motions and editing the textual description accordingly, resulting in 26850 motion examples in the training set. Additionally, we benefit from the GTA-Human dataset [4] built from an open-world action game providing SMPL annotations over" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15041" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 72, + 109, + 135 + ], + "blocks": [ + { + "bbox": [ + 51, + 72, + 109, + 135 + ], + "lines": [ + { + "bbox": [ + 51, + 72, + 109, + 135 + ], + "spans": [ + { + "bbox": [ + 51, + 72, + 109, + 135 + ], + "type": "image", + "image_path": "4410f0feb8eabebd5f78beed0648e0da6755be18aa084f368bd1773f3420905a.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 61, + 140, + 272, + 152 + ], + "lines": [ + { + "bbox": [ + 61, + 140, + 272, + 152 + ], + "spans": [ + { + "bbox": [ + 61, + 140, + 272, + 152 + ], + "type": "text", + "content": "Figure 3. A few examples from our collected TPP dataset." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 113, + 72, + 167, + 134 + ], + "blocks": [ + { + "bbox": [ + 113, + 72, + 167, + 134 + ], + "lines": [ + { + "bbox": [ + 113, + 72, + 167, + 134 + ], + "spans": [ + { + "bbox": [ + 113, + 72, + 167, + 134 + ], + "type": "image", + "image_path": "dfdfb1c0f5e6d3f07251f6f6cf241937d78912177e753452a9d88f383b65d1fc.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 174, + 76, + 228, + 134 + ], + "blocks": [ + { + "bbox": [ + 174, + 76, + 228, + 134 + ], + "lines": [ + { + "bbox": [ + 174, + 76, + 228, + 134 + ], + "spans": [ + { + "bbox": [ + 174, + 76, + 228, + 134 + ], + "type": "image", + "image_path": "703290c9fd07ed1eaaed5db90d3dab7ae757ced27c0f9f76c8adf5974b75afb3.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 232, + 76, + 291, + 134 + ], + "blocks": [ + { + "bbox": [ + 232, + 76, + 291, + 134 + ], + "lines": [ + { + "bbox": [ + 232, + 76, + 291, + 134 + ], + "spans": [ + { + "bbox": [ + 232, + 76, + 291, + 134 + ], + "type": "image", + "image_path": "cae0220e04cd165447855d36513db42a2945aa190626041302df17b2831754a4.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 171, + 287, + 218 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 171, + 287, + 218 + ], + "spans": [ + { + "bbox": [ + 46, + 171, + 287, + 218 + ], + "type": "text", + "content": "laid on the virtual humans for 20000 motion samples. This dataset does not have any textual annotation, thus we use it for an unconditional training of our model simultaneous to its text-conditional training." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 219, + 287, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 219, + 287, + 266 + ], + "spans": [ + { + "bbox": [ + 46, + 219, + 287, + 266 + ], + "type": "text", + "content": "Since the existing mocap datasets are limited in the number of samples and their diversity, we also collected a large-scale dataset of in-the-wild human poses from image datasets as follows." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 281, + 287, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 281, + 287, + 460 + ], + "spans": [ + { + "bbox": [ + 46, + 281, + 287, + 460 + ], + "type": "text", + "content": "Large-scale Text Pseudo-Pose (TPP) dataset. Similar to [2], we have collected a dataset containing 35M pairs of human poses and their text descriptions from a few large-scale image-text datasets. We processed all images by running Detectron2 keypoint detector to find images with a single human, then extracted their 3D pseudo-pose SMPL annotations using a pre-trained PyMAF-X model [37]. We used the publicly available captions without any processing. This large-scale data overcomes the limitations of the existing mocap datasets by providing a wide variety of human poses and a huge number of (text, 3D pose) sample pairs despite being noisy. We do not extract any face or hand expressions from the aforementioned datasets. A few examples of the (pseudo-pose, text) pairs are shown in Figure 3." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 468, + 211, + 480 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 468, + 211, + 480 + ], + "spans": [ + { + "bbox": [ + 47, + 468, + 211, + 480 + ], + "type": "text", + "content": "3.2. Diffusion Models Background" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 486, + 287, + 606 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 486, + 287, + 606 + ], + "spans": [ + { + "bbox": [ + 46, + 486, + 287, + 606 + ], + "type": "text", + "content": "Diffusion models are a class of generative model that convert Gaussian noise into samples from a learned distribution by iterative denoising. The forward process is a Gaussian noisin processing following a Markove chain, " + }, + { + "bbox": [ + 46, + 486, + 287, + 606 + ], + "type": "inline_equation", + "content": "\\{x_{t}\\}_{t = 0}^{T}" + }, + { + "bbox": [ + 46, + 486, + 287, + 606 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 46, + 486, + 287, + 606 + ], + "type": "inline_equation", + "content": "x_0" + }, + { + "bbox": [ + 46, + 486, + 287, + 606 + ], + "type": "text", + "content": " is drawn from the data distribution, in our case a set of 3D SMPL body poses. We can express the forward process as " + }, + { + "bbox": [ + 46, + 486, + 287, + 606 + ], + "type": "inline_equation", + "content": "q(x_{t}|x_{t - 1}) = \\mathcal{N}(\\sqrt{\\alpha_{t}} x_{t - 1},(1 - \\alpha_{t})\\mathbf{I})" + }, + { + "bbox": [ + 46, + 486, + 287, + 606 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 46, + 486, + 287, + 606 + ], + "type": "inline_equation", + "content": "\\alpha_{t}\\in (0,1)" + }, + { + "bbox": [ + 46, + 486, + 287, + 606 + ], + "type": "text", + "content": ". As is standard in training diffusion models, we learn to reverse the forward process by minimizing a noise-prediction loss [13]:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 58, + 613, + 287, + 634 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 613, + 287, + 634 + ], + "spans": [ + { + "bbox": [ + 58, + 613, + 287, + 634 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {s i m p l e}} = \\mathbb {E} _ {\\epsilon \\sim \\mathcal {N} (0, \\mathbf {I}), t \\sim U [ 1, T ]} \\left[ \\| \\epsilon_ {t} - \\epsilon_ {\\theta} (x _ {t}, c, t) \\| _ {2} ^ {2} \\right] \\tag {1}", + "image_path": "948232149c56eef0409c2440badf69d97295ac6668c36e22a9a0b664b6c9fe23.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 641, + 286, + 666 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 286, + 666 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 286, + 666 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 641, + 286, + 666 + ], + "type": "inline_equation", + "content": "c" + }, + { + "bbox": [ + 46, + 641, + 286, + 666 + ], + "type": "text", + "content": " is the optional conditioning for the diffusion model, which in our cases are text descriptions." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "content": "In addition to this simple loss, we follow [21, 27] and optimize the hybrid loss, which also uses a loss " + }, + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "inline_equation", + "content": "L_{vlb}" + }, + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "content": " that adds a constraint on the estimated variational lower bound (VLB). The " + }, + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "inline_equation", + "content": "L_{vlb}" + }, + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "content": " term is applied the same way as in [21]." + } + ] + } + ], + "index": 12 + }, + { + "type": "table", + "bbox": [ + 317, + 70, + 536, + 162 + ], + "blocks": [ + { + "bbox": [ + 317, + 70, + 536, + 162 + ], + "lines": [ + { + "bbox": [ + 317, + 70, + 536, + 162 + ], + "spans": [ + { + "bbox": [ + 317, + 70, + 536, + 162 + ], + "type": "table", + "html": "
MethodR-Precision ↑FID ↓Diversity ↑
Real0.797±0.0020.002±0.0029.5±0.65
J2LP[[1]]0.486±.00211.02±.0467.676±.058
MDM[[35]]0.611±.0070.544±.0449.559±.086
T2M[[9]]0.740±.0031.067±.0029.188±.002
MAA0.6755±.0020.7740±0.0078.23±0.064
", + "image_path": "6523353753481331ddf8199b00fe3cdd2559ff1912157f02069458f57b777df9.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_body" + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 163, + 545, + 196 + ], + "lines": [ + { + "bbox": [ + 305, + 163, + 545, + 196 + ], + "spans": [ + { + "bbox": [ + 305, + 163, + 545, + 196 + ], + "type": "text", + "content": "Table 1. Quantitative results on the HumanML3D test set. We run our evaluation 20 times and " + }, + { + "bbox": [ + 305, + 163, + 545, + 196 + ], + "type": "inline_equation", + "content": "\\pm" + }, + { + "bbox": [ + 305, + 163, + 545, + 196 + ], + "type": "text", + "content": " indicates the " + }, + { + "bbox": [ + 305, + 163, + 545, + 196 + ], + "type": "inline_equation", + "content": "95\\%" + }, + { + "bbox": [ + 305, + 163, + 545, + 196 + ], + "type": "text", + "content": " confidence interval." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 305, + 205, + 545, + 241 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 205, + 545, + 241 + ], + "spans": [ + { + "bbox": [ + 305, + 205, + 545, + 241 + ], + "type": "text", + "content": "We follow [12, 31] and parameterize our models using " + }, + { + "bbox": [ + 305, + 205, + 545, + 241 + ], + "type": "inline_equation", + "content": "v" + }, + { + "bbox": [ + 305, + 205, + 545, + 241 + ], + "type": "text", + "content": "-parameterization (" + }, + { + "bbox": [ + 305, + 205, + 545, + 241 + ], + "type": "inline_equation", + "content": "v_{t} = \\alpha_{t}\\epsilon - \\sigma_{t}x" + }, + { + "bbox": [ + 305, + 205, + 545, + 241 + ], + "type": "text", + "content": ") rather than predicting " + }, + { + "bbox": [ + 305, + 205, + 545, + 241 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 305, + 205, + 545, + 241 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 305, + 205, + 545, + 241 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 305, + 205, + 545, + 241 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 250, + 426, + 262 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 250, + 426, + 262 + ], + "spans": [ + { + "bbox": [ + 306, + 250, + 426, + 262 + ], + "type": "text", + "content": "3.3. Make-An-Animation" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "spans": [ + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "type": "text", + "content": "We represent an avatar body pose, " + }, + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "type": "text", + "content": ", via 3D SMPL body parameters and an avatar motion as a sequence of body poses for " + }, + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "type": "text", + "content": " frames, " + }, + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "type": "inline_equation", + "content": "[P_1, P_2, \\dots, P_N]" + }, + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "type": "text", + "content": ". We use 6D continuous SMPL representation for 21 body joints and the root orient. We additionally represent the global position per frame via a 3D vector indicating the avatar's position in each of the " + }, + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "type": "inline_equation", + "content": "x, y, z" + }, + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "type": "text", + "content": " dimensions, resulting in each " + }, + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "type": "inline_equation", + "content": "P_i \\in \\mathbb{R}^{135}" + }, + { + "bbox": [ + 304, + 269, + 545, + 448 + ], + "type": "text", + "content": ". Make-An-Animation is built from three major components: (1) a pre-trained language model trained on a large-scale language data (T5-XXL [26]), (2) a text-to-3D diffusion based pose generation model trained on our collected TPP dataset, and (3) a set of temporal convolution and attention layers extending the static pose generation model to the temporal dimension for motion generation and capturing the dependencies between the frames." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 449, + 545, + 580 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 449, + 545, + 580 + ], + "spans": [ + { + "bbox": [ + 305, + 449, + 545, + 580 + ], + "type": "text", + "content": "We follow [12] and use v-prediction parameterization " + }, + { + "bbox": [ + 305, + 449, + 545, + 580 + ], + "type": "inline_equation", + "content": "(v_{t} = \\alpha_{t}\\epsilon -\\sigma_{t}x)" + }, + { + "bbox": [ + 305, + 449, + 545, + 580 + ], + "type": "text", + "content": " to train our pose and motion diffusion models for numerical stability. Our denoising model in the above U-Net architecture operates on all motion frames at the same time resulting in a higher temporal coherence in the generated motions compared to the autoregressive frameworks [35] and does not require any specific loss on the motion velocity for a smooth motion synthesis. We also benefit from classifier free guidance [14] at inference by conditioning our model on a null text during training for " + }, + { + "bbox": [ + 305, + 449, + 545, + 580 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 305, + 449, + 545, + 580 + ], + "type": "text", + "content": " of the time." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 306, + 597, + 457, + 609 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 597, + 457, + 609 + ], + "spans": [ + { + "bbox": [ + 306, + 597, + 457, + 609 + ], + "type": "text", + "content": "3.3.1 Text-to-3D Pose Generation" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": "We train a U-Net based diffusion model to generate 3D SMPL pose parameters conditioning on text embeddings from a large frozen language model [26]. Inspired by the image and video generation models [32], we reshape the pose inputs to " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "B \\times C \\times 1 \\times 1" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "B" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": " indicating batch size and channel dimension of 135, respectively. Our U-Net model is built from a sequence of (1) Residual blocks with 1x1 2D-convolution layers conditioned on the diffu" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15042" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 62, + 91, + 275, + 201 + ], + "blocks": [ + { + "bbox": [ + 62, + 91, + 275, + 201 + ], + "lines": [ + { + "bbox": [ + 62, + 91, + 275, + 201 + ], + "spans": [ + { + "bbox": [ + 62, + 91, + 275, + 201 + ], + "type": "image", + "image_path": "9f38604501a931b869b823c882a6b8880d19bf2531644212a9f1d40b01b75c3e.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 71, + 204, + 279, + 213 + ], + "lines": [ + { + "bbox": [ + 71, + 204, + 279, + 213 + ], + "spans": [ + { + "bbox": [ + 71, + 204, + 279, + 213 + ], + "type": "text", + "content": "(a) Which motion corresponds better with the textual description?" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 312, + 92, + 517, + 201 + ], + "blocks": [ + { + "bbox": [ + 312, + 92, + 517, + 201 + ], + "lines": [ + { + "bbox": [ + 312, + 92, + 517, + 201 + ], + "spans": [ + { + "bbox": [ + 312, + 92, + 517, + 201 + ], + "type": "image", + "image_path": "7c1d16a5fe0d6266594b338413ad1fc8fd92871303265f7e08511d782cf62e6a.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 359, + 204, + 465, + 213 + ], + "lines": [ + { + "bbox": [ + 359, + 204, + 465, + 213 + ], + "spans": [ + { + "bbox": [ + 359, + 204, + 465, + 213 + ], + "type": "text", + "content": "(b) Which motion is more realistic?" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 226, + 547, + 258 + ], + "lines": [ + { + "bbox": [ + 46, + 226, + 547, + 258 + ], + "spans": [ + { + "bbox": [ + 46, + 226, + 547, + 258 + ], + "type": "text", + "content": "Figure 4. Human Evaluation. Here we compare each baseline against our model, MAA, in terms of text alignment and motion realism. The results are reported as the percentage of the majority vote raters that preferred our method to each baseline on our curated 400 prompts set." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 58, + 286, + 269, + 395 + ], + "blocks": [ + { + "bbox": [ + 58, + 286, + 269, + 395 + ], + "lines": [ + { + "bbox": [ + 58, + 286, + 269, + 395 + ], + "spans": [ + { + "bbox": [ + 58, + 286, + 269, + 395 + ], + "type": "image", + "image_path": "817dea198838115243d293082e25f811218002fb5459034c461035860edba322.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 400, + 288, + 456 + ], + "lines": [ + { + "bbox": [ + 46, + 400, + 288, + 456 + ], + "spans": [ + { + "bbox": [ + 46, + 400, + 288, + 456 + ], + "type": "text", + "content": "Figure 5. Ablation Study. Here we compare each ablated model against our model, MAA, in terms text alignment and motion realism. The results are reported as the percentage of the majority vote raters that preferred our method to each baseline on our curated 400 prompts set." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 475, + 287, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 475, + 287, + 536 + ], + "spans": [ + { + "bbox": [ + 46, + 475, + 287, + 536 + ], + "type": "text", + "content": "sion time-step embedding and text embedding, and (2) Attention Blocks attending to the textual information and the diffusion time-step. We train this network on our large-scale TPP dataset where we set translation parameters to zero in all training examples, i.e., human at the center of the scene." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 551, + 216, + 563 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 551, + 216, + 563 + ], + "spans": [ + { + "bbox": [ + 47, + 551, + 216, + 563 + ], + "type": "text", + "content": "3.3.2 Temporal and Attention Layers" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 570, + 287, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 287, + 616 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 287, + 616 + ], + "type": "text", + "content": "In order to expand the aforementioned pose generation model to learn the temporal dimension for motion generation, we modify the convolutional and attention layers of the U-Net as follows." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": "We reshape the input motion sequence to a tensor of shape " + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "inline_equation", + "content": "B \\times C \\times N \\times 1 \\times 1" + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": " is the length of the pose representation and " + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": " is the number of frames. Inspired by [32, 12], we stack a 1D temporal convolution layer following each 1x1 2D-convolution. This allows us to train the new 1D temporal layers from scratch while loading the pre-trained convolution weights from the pose generation model. We set the kernel size of these temporal convolution" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 277, + 545, + 350 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 277, + 545, + 350 + ], + "spans": [ + { + "bbox": [ + 304, + 277, + 545, + 350 + ], + "type": "text", + "content": "layers to 3 opposed to the unit kernel size of the 2D convolutions. We apply a similar dimension decomposition strategy to the attention layers, where we stack a newly initialized temporal attention layer to each pre-trained attention block from the pose generation network. For the temporal attention layers we utilize a Rotary Position Embedding [33]." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 358, + 388, + 372 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 358, + 388, + 372 + ], + "spans": [ + { + "bbox": [ + 306, + 358, + 388, + 372 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 379, + 545, + 437 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 379, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 304, + 379, + 545, + 437 + ], + "type": "text", + "content": "We compare the performance of our motion generation model with the existing state-of-the-art text-to-human-motion generation models through human evaluation on 400 crowd-sourced prompts and automatic metrics on the HumanML3D test set." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 444, + 416, + 455 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 444, + 416, + 455 + ], + "spans": [ + { + "bbox": [ + 306, + 444, + 416, + 455 + ], + "type": "text", + "content": "4.1. Automatic Metrics" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 462, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 462, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 462, + 545, + 713 + ], + "type": "text", + "content": "We perform an automatic evaluation on the HumanML3D test set in terms of Fréchet Distance (FID), R-Precision and Diversity scores. FID measures both diversity and quality of the samples comparing its distribution with the ground truth test set while R-Precision measures faithfulness between each generated motion and its input prompt. Diversity measures the variance of the generated motions across all descriptions. To compute the above scores, a motion encoder was jointly trained with a text encoder via a contrastive loss by [9]. We use the same encoder to extract text and motion embeddings. Since this model has been trained and optimized on the 263-dimensional pose representation vector, we transform both the ground-truth SMPL data and our generated samples similarly following the transformations provided by [11] before computing the above metrics. We upsample our generations to 196 frames and keep that fixed for the ground truth samples and our outputs while computing the above metrics. Opposed to our baselines, we have not optimized our model on the 263-dimensional motion representation, but achieve a comparable performance in all metrics as reported in Table 1." + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15043" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 160, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 160, + 83 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 160, + 83 + ], + "type": "text", + "content": "4.2. Human Evaluation" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 91, + 290, + 355 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 91, + 290, + 355 + ], + "spans": [ + { + "bbox": [ + 46, + 91, + 290, + 355 + ], + "type": "text", + "content": "To evaluate the generalization ability of our model in synthesizing more challenging human poses and motions, we collected an evaluation set from Amazon Mechanical Turk (AMT) that consists of 400 prompts. We asked annotators for prompts that described an action along with some context of the scene. We filtered out prompts based on ethical concerns to remove any references to children or NSFW content. These prompts were selected without generating any poses or images for them, and were kept fixed for all of our evaluations. This test set is released here1. We generated animated poses from all models with no translation to measure the correctness and quality of the body pose and motion. We show raters a text description and the corresponding rendered avatars from two models and ask them which output better matches the input text. For each comparison, we use the majority vote from 7 different annotators on 400 prompts as the final result, reported in Figure 4. This study confirms the superiority of our model and the impact of our large-scale TPP dataset in human motion generation and overcoming the limitations of the mocap datasets. A few motion samples generated by our model are shown in Figure 8 and more are included on our webpage1." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 363, + 149, + 374 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 363, + 149, + 374 + ], + "spans": [ + { + "bbox": [ + 47, + 363, + 149, + 374 + ], + "type": "text", + "content": "4.3. Ablation Studies" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 381, + 289, + 644 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 381, + 289, + 644 + ], + "spans": [ + { + "bbox": [ + 46, + 381, + 289, + 644 + ], + "type": "text", + "content": "To disentangle and study the impact of our U-Net architecture versus the impact on our TPP dataset on our results, we implemented and trained an alternative diffusion model as a decoder-only transformer with a causal attention mask to generate 3D pose representations from text. This model operates on a sequence of tokenized captions and their text embeddings, the diffusion time-step embedding, the noised body pose and root orient representations, and two final pose and orientation queries to predict the unnoised pose and root orientation, respectively. We pre-trained this model on our TPP dataset, then expanded the model for motion synthesis via adding three additional tokens per frame for pose, root orient, and translation paramters. We trained this model on the mocap datasets described in Sec 3.1 and compared its performance with our U-Net model via Amazon Mechanical Turk. As a result, " + }, + { + "bbox": [ + 46, + 381, + 289, + 644 + ], + "type": "inline_equation", + "content": "58\\%" + }, + { + "bbox": [ + 46, + 381, + 289, + 644 + ], + "type": "text", + "content": " of the raters preferred the generations from our U-Net architecture. This experiment confirms the superiority of the U-Net model versus its auto-regressive alternatives. We also ablated the impact of temporal attention modules on the final quality of the samples resulting in " + }, + { + "bbox": [ + 46, + 381, + 289, + 644 + ], + "type": "inline_equation", + "content": "54\\%" + }, + { + "bbox": [ + 46, + 381, + 289, + 644 + ], + "type": "text", + "content": " of the users preferring samples from a U-Net with temporal attention." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 645, + 288, + 681 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 645, + 288, + 681 + ], + "spans": [ + { + "bbox": [ + 46, + 645, + 288, + 681 + ], + "type": "text", + "content": "Training with the GTA data unconditionally made the convergence of the model faster although it didn't impact the samples' quality after convergence." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 59, + 681, + 288, + 694 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 681, + 288, + 694 + ], + "spans": [ + { + "bbox": [ + 59, + 681, + 288, + 694 + ], + "type": "text", + "content": "Additionally, we experimented with training our U-Net" + } + ] + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 358, + 78, + 527, + 160 + ], + "blocks": [ + { + "bbox": [ + 334, + 145, + 345, + 272 + ], + "lines": [ + { + "bbox": [ + 334, + 145, + 345, + 272 + ], + "spans": [ + { + "bbox": [ + 334, + 145, + 345, + 272 + ], + "type": "text", + "content": "A person is playing football in playground" + } + ] + } + ], + "index": 6, + "angle": 270, + "type": "image_caption" + }, + { + "bbox": [ + 358, + 78, + 527, + 160 + ], + "lines": [ + { + "bbox": [ + 358, + 78, + 527, + 160 + ], + "spans": [ + { + "bbox": [ + 358, + 78, + 527, + 160 + ], + "type": "image", + "image_path": "99d8ae57a92f5c1b873b17f8455473633da3c82464e90b08ee1bce94f8b55f27.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 358, + 164, + 527, + 250 + ], + "blocks": [ + { + "bbox": [ + 358, + 164, + 527, + 250 + ], + "lines": [ + { + "bbox": [ + 358, + 164, + 527, + 250 + ], + "spans": [ + { + "bbox": [ + 358, + 164, + 527, + 250 + ], + "type": "image", + "image_path": "770a6c7a92c302d46258861724fc1dbada72027158d24c0c39cf24683b5f9c21.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 358, + 251, + 527, + 333 + ], + "blocks": [ + { + "bbox": [ + 358, + 251, + 527, + 333 + ], + "lines": [ + { + "bbox": [ + 358, + 251, + 527, + 333 + ], + "spans": [ + { + "bbox": [ + 358, + 251, + 527, + 333 + ], + "type": "image", + "image_path": "5550d41fb7701fde2559aaee472deda3fa78cda78910aef9649ec4e0fda5bfeb.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 358, + 361, + 527, + 443 + ], + "blocks": [ + { + "bbox": [ + 335, + 451, + 345, + 544 + ], + "lines": [ + { + "bbox": [ + 335, + 451, + 345, + 544 + ], + "spans": [ + { + "bbox": [ + 335, + 451, + 345, + 544 + ], + "type": "text", + "content": "A person dancing in the street" + } + ] + } + ], + "index": 10, + "angle": 270, + "type": "image_caption" + }, + { + "bbox": [ + 358, + 361, + 527, + 443 + ], + "lines": [ + { + "bbox": [ + 358, + 361, + 527, + 443 + ], + "spans": [ + { + "bbox": [ + 358, + 361, + 527, + 443 + ], + "type": "image", + "image_path": "b147549a7d3b0619e62349fce672b863c3c8086476f733cf4d2d4bf1f3e95ee9.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 358, + 448, + 527, + 528 + ], + "blocks": [ + { + "bbox": [ + 358, + 448, + 527, + 528 + ], + "lines": [ + { + "bbox": [ + 358, + 448, + 527, + 528 + ], + "spans": [ + { + "bbox": [ + 358, + 448, + 527, + 528 + ], + "type": "image", + "image_path": "e6d1195e1ea003346f3a827ff592fa77cecdffbceb1559cf6afe573801f29ea8.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 358, + 529, + 527, + 609 + ], + "blocks": [ + { + "bbox": [ + 358, + 529, + 527, + 609 + ], + "lines": [ + { + "bbox": [ + 358, + 529, + 527, + 609 + ], + "spans": [ + { + "bbox": [ + 358, + 529, + 527, + 609 + ], + "type": "image", + "image_path": "b8765ec569532be7bdfd53cbc8ed37a49db2993571219f219a488acca0877fea.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 612, + 547, + 678 + ], + "lines": [ + { + "bbox": [ + 304, + 612, + 547, + 678 + ], + "spans": [ + { + "bbox": [ + 304, + 612, + 547, + 678 + ], + "type": "text", + "content": "Figure 6. Diverse samples generated by Make-An-Animation for text conditional motion generation. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. For a better visualization, frames are down-sampled along the temporal dimension and distributed horizontally." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 58, + 702, + 201, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 201, + 713 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 201, + 713 + ], + "type": "text", + "content": "1 https://azadis.github.io/make-an-animation" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "15044" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 90, + 286, + 205 + ], + "blocks": [ + { + "bbox": [ + 115, + 73, + 183, + 82 + ], + "lines": [ + { + "bbox": [ + 115, + 73, + 183, + 82 + ], + "spans": [ + { + "bbox": [ + 115, + 73, + 183, + 82 + ], + "type": "text", + "content": "MAA Generations" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 49, + 90, + 286, + 205 + ], + "lines": [ + { + "bbox": [ + 49, + 90, + 286, + 205 + ], + "spans": [ + { + "bbox": [ + 49, + 90, + 286, + 205 + ], + "type": "image", + "image_path": "ca571b6c0bd8a486c30d92d6e17e4ab78f20054460a9aaac50b42d15fa1eaeff.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 94, + 206, + 212, + 215 + ], + "lines": [ + { + "bbox": [ + 94, + 206, + 212, + 215 + ], + "spans": [ + { + "bbox": [ + 94, + 206, + 212, + 215 + ], + "type": "text", + "content": "A person wrestles a bear in the forest" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 308, + 91, + 545, + 205 + ], + "blocks": [ + { + "bbox": [ + 364, + 73, + 470, + 83 + ], + "lines": [ + { + "bbox": [ + 364, + 73, + 470, + 83 + ], + "spans": [ + { + "bbox": [ + 364, + 73, + 470, + 83 + ], + "type": "text", + "content": "Nearest Neighbour Example" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 308, + 91, + 545, + 205 + ], + "lines": [ + { + "bbox": [ + 308, + 91, + 545, + 205 + ], + "spans": [ + { + "bbox": [ + 308, + 91, + 545, + 205 + ], + "type": "image", + "image_path": "84f7f6cd8a5319c361eed8fe9ffd976008a42a8d528300270e0e335e00be6b35.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 371, + 205, + 485, + 213 + ], + "lines": [ + { + "bbox": [ + 371, + 205, + 485, + 213 + ], + "spans": [ + { + "bbox": [ + 371, + 205, + 485, + 213 + ], + "type": "text", + "content": "a person puts both arms into the air" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 48, + 232, + 286, + 344 + ], + "blocks": [ + { + "bbox": [ + 48, + 232, + 286, + 344 + ], + "lines": [ + { + "bbox": [ + 48, + 232, + 286, + 344 + ], + "spans": [ + { + "bbox": [ + 48, + 232, + 286, + 344 + ], + "type": "image", + "image_path": "b421531488792713fad60a3b93fbaff18d581ca8fe2f06fadf104a235358bebc.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 113, + 346, + 209, + 354 + ], + "lines": [ + { + "bbox": [ + 113, + 346, + 209, + 354 + ], + "spans": [ + { + "bbox": [ + 113, + 346, + 209, + 354 + ], + "type": "text", + "content": "A person is practicing the flute" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 308, + 232, + 545, + 345 + ], + "blocks": [ + { + "bbox": [ + 308, + 232, + 545, + 345 + ], + "lines": [ + { + "bbox": [ + 308, + 232, + 545, + 345 + ], + "spans": [ + { + "bbox": [ + 308, + 232, + 545, + 345 + ], + "type": "image", + "image_path": "d981404c575242b5fd968461147e9fcfaf3b16f747c2d4f2082bf32689ca74b7.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 373, + 346, + 476, + 354 + ], + "lines": [ + { + "bbox": [ + 373, + 346, + 476, + 354 + ], + "spans": [ + { + "bbox": [ + 373, + 346, + 476, + 354 + ], + "type": "text", + "content": "a person clapping with his hands" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 48, + 367, + 286, + 479 + ], + "blocks": [ + { + "bbox": [ + 48, + 367, + 286, + 479 + ], + "lines": [ + { + "bbox": [ + 48, + 367, + 286, + 479 + ], + "spans": [ + { + "bbox": [ + 48, + 367, + 286, + 479 + ], + "type": "image", + "image_path": "ecfe3bf181726948b0aa5d32657a80aa31ab14ac3ce87253b3ff91a8b0575518.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 94, + 483, + 232, + 493 + ], + "lines": [ + { + "bbox": [ + 94, + 483, + 232, + 493 + ], + "spans": [ + { + "bbox": [ + 94, + 483, + 232, + 493 + ], + "type": "text", + "content": "A person is sawing a branch off of a tree" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 45, + 504, + 546, + 548 + ], + "lines": [ + { + "bbox": [ + 45, + 504, + 546, + 548 + ], + "spans": [ + { + "bbox": [ + 45, + 504, + 546, + 548 + ], + "type": "text", + "content": "Figure 7. Left: samples generated by Make-An-Animation for text conditional motion generation. Right: The nearest neighbor example for each of the generated samples found from the mocap training set based on motion and text clip similarity scores. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. For a better visualization, frames are distributed horizontally." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 308, + 367, + 545, + 479 + ], + "blocks": [ + { + "bbox": [ + 308, + 367, + 545, + 479 + ], + "lines": [ + { + "bbox": [ + 308, + 367, + 545, + 479 + ], + "spans": [ + { + "bbox": [ + 308, + 367, + 545, + 479 + ], + "type": "image", + "image_path": "b9f83de2b62046177c659e6d7cc6d30e46f2576fe90dd30f6d2b196df5bf45db.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 320, + 482, + 535, + 500 + ], + "lines": [ + { + "bbox": [ + 320, + 482, + 535, + 500 + ], + "spans": [ + { + "bbox": [ + 320, + 482, + 535, + 500 + ], + "type": "text", + "content": "a man raises his hands to his chest, claps them together, then lowers them back to his sides" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 568, + 287, + 652 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 568, + 287, + 652 + ], + "spans": [ + { + "bbox": [ + 46, + 568, + 287, + 652 + ], + "type": "text", + "content": "model on the mocap training set from scratch and without pre-training. However, we observed stability and convergence issues in this setting even with various learning rates and warming up updates. The pre-training stage on the large-scale dataset was therefore a stable solution resulting in high quality motion samples in the end. All ablation results are summarized in Figure 5." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 47, + 659, + 159, + 672 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 659, + 159, + 672 + ], + "spans": [ + { + "bbox": [ + 47, + 659, + 159, + 672 + ], + "type": "text", + "content": "4.4. Qualitative Studies" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "type": "text", + "content": "In Figure 7, we visualize the generalization capability of our model in synthesizing novel motions. We investigate the existence of similar prompts or motions in the train" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 568, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 568, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 568, + 545, + 712 + ], + "type": "text", + "content": "ing data for each synthesized motion via a nearest neighbor search. We extract the motion embedding and text embedding for each sample in our test set of prompts as well as our mocap training data using a pre-trained motionCLIP model [34, 16] that has learned a joint motion and language embedding space. For each synthesized motion, we find the top 6 motions and prompts from the training data with the highest cosine similarity scores. As shown in the figure, our model has generalized to new motions that did not exist in the training data. In addition, Figure 6 illustrates multiple diverse motions generated by our model for different text prompt." + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15045" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 76, + 281, + 196 + ], + "blocks": [ + { + "bbox": [ + 49, + 76, + 281, + 196 + ], + "lines": [ + { + "bbox": [ + 49, + 76, + 281, + 196 + ], + "spans": [ + { + "bbox": [ + 49, + 76, + 281, + 196 + ], + "type": "image", + "image_path": "bfa30e679e5c72d388a9e401992ec85602fa91aafd101aea0de0bfbd322f6648.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 94, + 198, + 226, + 207 + ], + "lines": [ + { + "bbox": [ + 94, + 198, + 226, + 207 + ], + "spans": [ + { + "bbox": [ + 94, + 198, + 226, + 207 + ], + "type": "text", + "content": "A person is doing a handstand on a cactus" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 314, + 99, + 545, + 196 + ], + "blocks": [ + { + "bbox": [ + 314, + 99, + 545, + 196 + ], + "lines": [ + { + "bbox": [ + 314, + 99, + 545, + 196 + ], + "spans": [ + { + "bbox": [ + 314, + 99, + 545, + 196 + ], + "type": "image", + "image_path": "ba5d9b87d012d84495342e7dfc2e0c1a4705f2f8fe094567fea5724c6828f1af.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 380, + 197, + 466, + 205 + ], + "lines": [ + { + "bbox": [ + 380, + 197, + 466, + 205 + ], + "spans": [ + { + "bbox": [ + 380, + 197, + 466, + 205 + ], + "type": "text", + "content": "A person kicks a soccer ball" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 49, + 219, + 279, + 328 + ], + "blocks": [ + { + "bbox": [ + 49, + 219, + 279, + 328 + ], + "lines": [ + { + "bbox": [ + 49, + 219, + 279, + 328 + ], + "spans": [ + { + "bbox": [ + 49, + 219, + 279, + 328 + ], + "type": "image", + "image_path": "82f978aeb2350eb6eea71114941428390649b20eb978ac7c916327d4436546c5.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 86, + 330, + 217, + 339 + ], + "lines": [ + { + "bbox": [ + 86, + 330, + 217, + 339 + ], + "spans": [ + { + "bbox": [ + 86, + 330, + 217, + 339 + ], + "type": "text", + "content": "A person is rowing a small dingy in a river" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 314, + 212, + 545, + 329 + ], + "blocks": [ + { + "bbox": [ + 314, + 212, + 545, + 329 + ], + "lines": [ + { + "bbox": [ + 314, + 212, + 545, + 329 + ], + "spans": [ + { + "bbox": [ + 314, + 212, + 545, + 329 + ], + "type": "image", + "image_path": "f04008afad21d8211f0c71bef053c4cacdf8e04167f8b9594ebc4f05b2dc14d8.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 340, + 330, + 500, + 339 + ], + "lines": [ + { + "bbox": [ + 340, + 330, + 500, + 339 + ], + "spans": [ + { + "bbox": [ + 340, + 330, + 500, + 339 + ], + "type": "text", + "content": "A person is playing tennis at the Recreation Center" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 49, + 350, + 279, + 460 + ], + "blocks": [ + { + "bbox": [ + 49, + 350, + 279, + 460 + ], + "lines": [ + { + "bbox": [ + 49, + 350, + 279, + 460 + ], + "spans": [ + { + "bbox": [ + 49, + 350, + 279, + 460 + ], + "type": "image", + "image_path": "5dc2504192f488274b3f3e703945552b165baf030730221d0a6297a57d25f19a.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 101, + 461, + 211, + 470 + ], + "lines": [ + { + "bbox": [ + 101, + 461, + 211, + 470 + ], + "spans": [ + { + "bbox": [ + 101, + 461, + 211, + 470 + ], + "type": "text", + "content": "A volleyball player bumps a ball up" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 314, + 352, + 545, + 460 + ], + "blocks": [ + { + "bbox": [ + 314, + 352, + 545, + 460 + ], + "lines": [ + { + "bbox": [ + 314, + 352, + 545, + 460 + ], + "spans": [ + { + "bbox": [ + 314, + 352, + 545, + 460 + ], + "type": "image", + "image_path": "4d044153d9b28e995fec65730adaa4a28808b80184f62ae4a8ce2ebfc54b7270.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 352, + 461, + 498, + 471 + ], + "lines": [ + { + "bbox": [ + 352, + 461, + 498, + 471 + ], + "spans": [ + { + "bbox": [ + 352, + 461, + 498, + 471 + ], + "type": "text", + "content": "A photographer is looking through the camera" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 49, + 479, + 276, + 584 + ], + "blocks": [ + { + "bbox": [ + 49, + 479, + 276, + 584 + ], + "lines": [ + { + "bbox": [ + 49, + 479, + 276, + 584 + ], + "spans": [ + { + "bbox": [ + 49, + 479, + 276, + 584 + ], + "type": "image", + "image_path": "f4e92455eb3fbdd47409027ff835b39d5151e7be18247c48047b98e0b7c2d3ef.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 74, + 585, + 231, + 594 + ], + "lines": [ + { + "bbox": [ + 74, + 585, + 231, + 594 + ], + "spans": [ + { + "bbox": [ + 74, + 585, + 231, + 594 + ], + "type": "text", + "content": "A person is shoveling the driveway after a blizzard" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 314, + 489, + 545, + 584 + ], + "blocks": [ + { + "bbox": [ + 314, + 489, + 545, + 584 + ], + "lines": [ + { + "bbox": [ + 314, + 489, + 545, + 584 + ], + "spans": [ + { + "bbox": [ + 314, + 489, + 545, + 584 + ], + "type": "image", + "image_path": "5c21ffc224a3bc82285b3aae5aff2d43ff2727d36f32df654872bfcf8c4162e9.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 364, + 585, + 487, + 594 + ], + "lines": [ + { + "bbox": [ + 364, + 585, + 487, + 594 + ], + "spans": [ + { + "bbox": [ + 364, + 585, + 487, + 594 + ], + "type": "text", + "content": "A person is sitting down on the ground" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 606, + 546, + 628 + ], + "lines": [ + { + "bbox": [ + 46, + 606, + 546, + 628 + ], + "spans": [ + { + "bbox": [ + 46, + 606, + 546, + 628 + ], + "type": "text", + "content": "Figure 8. Samples generated by Make-An-Animation for text conditional motion generation. The lighting of the body models represents progress across time. Darker color indicates later frames in the sequence. For a better visualization, frames are distributed horizontally." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "bbox": [ + 47, + 647, + 119, + 659 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 647, + 119, + 659 + ], + "spans": [ + { + "bbox": [ + 47, + 647, + 119, + 659 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 46, + 677, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 287, + 715 + ], + "type": "text", + "content": "Current text-to-motion models are hindered by relatively small-scale motion capture datasets, as evident by their poor performance on more diverse, in-the-wild prompts." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 305, + 648, + 547, + 709 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 648, + 547, + 709 + ], + "spans": [ + { + "bbox": [ + 305, + 648, + 547, + 709 + ], + "type": "text", + "content": "Motivated by this shortcoming, we present Make-An-Animation, a human motion generation model trained on a collection of large-scale static pseudo-pose and motion capture data. As we demonstrate through our ablations and human studies comparing to prior works, pre-training on the" + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15046" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 167 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 167 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 167 + ], + "type": "text", + "content": "large-scale TPP dataset significantly improves performance on captions outside of the distribution of motion capture data. Furthermore, our novel U-Net architecture enables a seamless transition between static pose pre-training and dynamic pose (i.e., motion) fine-tuning. Altogether, this work paves the way to leverage large-scale image and video datasets for learning generation of human 3D pose parameters." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 307, + 72, + 365, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 72, + 365, + 83 + ], + "spans": [ + { + "bbox": [ + 307, + 72, + 365, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 307, + 91, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 311, + 91, + 545, + 133 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 91, + 545, + 133 + ], + "spans": [ + { + "bbox": [ + 311, + 91, + 545, + 133 + ], + "type": "text", + "content": "[1] Chaitanya Ahuja and Louis-Philippe Morency. Language2pose: Natural language grounded pose forecasting. IEEE International Conference on 3D Vision (3DV), pages 719-728, 2019." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 311, + 135, + 547, + 178 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 135, + 547, + 178 + ], + "spans": [ + { + "bbox": [ + 311, + 135, + 547, + 178 + ], + "type": "text", + "content": "[2] Samaneh Azadi, Thomas Hayes, Akbar Shah, Guan Pang, Devi Parikh, and Sonal Gupta. Text-conditional contextualized avatars for zero-shot personalization. arXiv preprint arXiv:2304.07410, 2023." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 311, + 180, + 547, + 212 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 180, + 547, + 212 + ], + "spans": [ + { + "bbox": [ + 311, + 180, + 547, + 212 + ], + "type": "text", + "content": "[3] Rania Briq, Pratika Kochar, and Juergen Gall. Towards better adversarial synthesis of human images from text. arXiv preprint arXiv:2107.01869, 2021." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 311, + 214, + 547, + 255 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 214, + 547, + 255 + ], + "spans": [ + { + "bbox": [ + 311, + 214, + 547, + 255 + ], + "type": "text", + "content": "[4] Zhongang Cai, Mingyuan Zhang, Jiawei Ren, Chen Wei, Daxuan Ren, Zhengyu Lin, Haiyu Zhao, Lei Yang, and Zwei Liu. Playing for 3d human recovery. arXiv preprint arXiv:2110.07588, 2021." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 311, + 258, + 547, + 300 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 258, + 547, + 300 + ], + "spans": [ + { + "bbox": [ + 311, + 258, + 547, + 300 + ], + "type": "text", + "content": "[5] Pablo Cervantes, Yusuke Sekikawa, Ikuro Sato, and Koichi Shinoda. Implicit neural representations for variable length human motion generation. European Conference on Computer Vision (ECCV), 2022." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 311, + 302, + 545, + 335 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 302, + 545, + 335 + ], + "spans": [ + { + "bbox": [ + 311, + 302, + 545, + 335 + ], + "type": "text", + "content": "[6] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Advances in Neural Information Processing Systems (NeurIPS), 34, 2021." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 311, + 336, + 545, + 390 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 336, + 545, + 390 + ], + "spans": [ + { + "bbox": [ + 311, + 336, + 545, + 390 + ], + "type": "text", + "content": "[7] Anindita Ghosh, Noshaba Cheema, Cennet Oguz, Christian Theobalt, and Philipp Slusallek. Synthesis of compositional animations from textual descriptions. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 1396-1406, October 2021." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 311, + 392, + 545, + 434 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 392, + 545, + 434 + ], + "spans": [ + { + "bbox": [ + 311, + 392, + 545, + 434 + ], + "type": "text", + "content": "[8] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In Advances in Neural Information Processing Systems, 2014." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 311, + 436, + 545, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 436, + 545, + 491 + ], + "spans": [ + { + "bbox": [ + 311, + 436, + 545, + 491 + ], + "type": "text", + "content": "[9] Chuan Guo, Shihao Zou, Xinxin Zuo, Sen Wang, Wei Ji, Xingyu Li, and Li Cheng. Generating diverse and natural 3d human motions from text. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 5152-5161, June 2022." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 307, + 491, + 545, + 545 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 491, + 545, + 545 + ], + "spans": [ + { + "bbox": [ + 307, + 491, + 545, + 545 + ], + "type": "text", + "content": "[10] Chuan Guo, Shihao Zou, Xinxin Zuo, Sen Wang, Wei Ji, Xingyu Li, and Li Cheng. Generating diverse and natural 3d human motions from text. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 5152-5161, June 2022." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 307, + 547, + 545, + 601 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 547, + 545, + 601 + ], + "spans": [ + { + "bbox": [ + 307, + 547, + 545, + 601 + ], + "type": "text", + "content": "[11] Chuan Guo, Xinxin Zuo, Sen Wang, Shihao Zou, Qingyao Sun, Annan Deng, Minglun Gong, and Li Cheng. Action2motion: Conditioned generation of 3d human motions. Proceedings of the 28th ACM International Conference on Multimedia, pages 2021-2029, 2020." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 307, + 602, + 545, + 656 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 602, + 545, + 656 + ], + "spans": [ + { + "bbox": [ + 307, + 602, + 545, + 656 + ], + "type": "text", + "content": "[12] Jonathan Ho, William Chan, Chitwan Saharia, Jay Whang, Ruiqi Gao, Alexey Gritsenko, Diederik P Kingma, Ben Poole, Mohammad Norouzi, David J Fleet, et al. Imagen video: High definition video generation with diffusion models. arXiv preprint arXiv:2210.02303, 2022." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 307, + 658, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 658, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 307, + 658, + 545, + 689 + ], + "type": "text", + "content": "[13] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Advances in Neural Information Processing Systems (NeurIPS), 33, 2020." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 691, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 691, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 691, + 545, + 713 + ], + "type": "text", + "content": "[14] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. arXiv preprint arXiv:2207.12598, 2022." + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "15047" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[15] Fangzhou Hong, Mingyuan Zhang, Liang Pan, Zhongang Cai, Lei Yang, and Ziwei Liu. Avatarclip: Zero-shot text-driven generation and animation of 3d avatars. ACM Transactions on Graphics (TOG), 41(4):1-19, 2022." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 119, + 287, + 152 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 119, + 287, + 152 + ], + "spans": [ + { + "bbox": [ + 49, + 119, + 287, + 152 + ], + "type": "text", + "content": "[16] Jihoon Kim, Jiseob Kim, and Sungjoon Choi. Flame: Freeform language-based motion synthesis & editing. arXiv preprint arXiv:2209.00349, 2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 154, + 287, + 197 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 154, + 287, + 197 + ], + "spans": [ + { + "bbox": [ + 49, + 154, + 287, + 197 + ], + "type": "text", + "content": "[17] Hsin-Ying Lee, Xiaodong Yang, Ming-Yu Liu, Ting-Chun Wang, Yu-Ding Lu, Ming-Hsuan Yang, and Jan Kautz. Dancing to music. Advances in Neural Information Processing Systems (NeurIPS), 32, 2019." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 200, + 287, + 243 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 200, + 287, + 243 + ], + "spans": [ + { + "bbox": [ + 49, + 200, + 287, + 243 + ], + "type": "text", + "content": "[18] Ruilong Li, Shan Yang, David A. Ross, and Angjoo Kanazawa. Ai choreographer: Music conditioned 3d dance generation with aist++. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), 2021." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 246, + 287, + 289 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 246, + 287, + 289 + ], + "spans": [ + { + "bbox": [ + 49, + 246, + 287, + 289 + ], + "type": "text", + "content": "[19] Naureen Mahmood, Nima Ghorbani, Nikolaus F. Troje, Gerard Pons-Moll, and Michael J. Black. AMASS: Archive of motion capture as surface shapes. In International Conference on Computer Vision, pages 5442-5451, Oct. 2019." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 292, + 287, + 335 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 292, + 287, + 335 + ], + "spans": [ + { + "bbox": [ + 49, + 292, + 287, + 335 + ], + "type": "text", + "content": "[20] Julieta Martinez, Michael J. Black, and Javier Romero. On human motion prediction using recurrent neural networks. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2017." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 338, + 287, + 380 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 338, + 287, + 380 + ], + "spans": [ + { + "bbox": [ + 49, + 338, + 287, + 380 + ], + "type": "text", + "content": "[21] Alexander Quinn Nichol and Prafulla Dhariwal. Improved denoising diffusion probabilistic models. In International Conference on Machine Learning, pages 8162-8171. PMLR, 2021." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 384, + 287, + 437 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 384, + 287, + 437 + ], + "spans": [ + { + "bbox": [ + 49, + 384, + 287, + 437 + ], + "type": "text", + "content": "[22] Georgios Pavlakos, Vasileios Choutas, Nima Ghorbani, Timo Bolkart, Ahmed A. A. Osman, Dimitrios Tzionas, and Michael J. Black. Expressive body capture: 3d hands, face, and body from a single image. In Conference on Computer Vision and Pattern Recognition (CVPR), 2019." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 441, + 287, + 494 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 441, + 287, + 494 + ], + "spans": [ + { + "bbox": [ + 49, + 441, + 287, + 494 + ], + "type": "text", + "content": "[23] Mathis Petrovich, Michael J. Black, and Gül Varol. Action-conditioned 3D human motion synthesis with transformer VAE. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 10985-10995, October 2021." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 498, + 287, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 498, + 287, + 529 + ], + "spans": [ + { + "bbox": [ + 49, + 498, + 287, + 529 + ], + "type": "text", + "content": "[24] Mathis Petrovich, Michael J. Black, and Gül Varol. Temos: Generating diverse human motions from textual descriptions. European Conference on Computer Vision (ECCV), 2022." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 533, + 287, + 575 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 533, + 287, + 575 + ], + "spans": [ + { + "bbox": [ + 49, + 533, + 287, + 575 + ], + "type": "text", + "content": "[25] Sigal Raab, Inbal Leibovitch, Peizhuo Li, Kfir Aberman, Olga Sorkine-Hornung, and Daniel Cohen-Or. Modi: Unconditional motion synthesis from diverse data. arXiv preprint arXiv:2206.08010, 2022." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 49, + 578, + 287, + 620 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 578, + 287, + 620 + ], + "spans": [ + { + "bbox": [ + 49, + 578, + 287, + 620 + ], + "type": "text", + "content": "[26] Colin Raffel, Noam Shazeer, Adam Roberts, Katherine Lee, Sharan Narang, Michael Matena, Yanqi Zhou, Wei Li, and Peter J. Liu. Exploring the limits of transfer learning with a unified text-to-text transformer. JMLR, 2020." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 49, + 624, + 287, + 666 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 624, + 287, + 666 + ], + "spans": [ + { + "bbox": [ + 49, + 624, + 287, + 666 + ], + "type": "text", + "content": "[27] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 49, + 670, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 670, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 49, + 670, + 287, + 712 + ], + "type": "text", + "content": "[28] Prasun Roy, Subhankar Ghosh, Saumik Bhattacharya, Umapada Pal, and Michael Blumenstein. Tips: Text-induced pose synthesis. European Conference on Computer Vision (ECCV), 2022." + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 687 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 308, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 308, + 73, + 545, + 116 + ], + "type": "text", + "content": "[29] Alejandro Hernandez Ruiz, Juergen Gall, and Francesc Moreno-Noguer. Human motion prediction via spatiotemporal inpainting. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), 2019." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 118, + 545, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 118, + 545, + 194 + ], + "spans": [ + { + "bbox": [ + 308, + 118, + 545, + 194 + ], + "type": "text", + "content": "[30] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S. Sara Mahdavi, Rapha Gontijo Lopes, Tim Salimans, Jonathan Ho, David J Fleet, and Mohammad Norouzi. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 197, + 545, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 197, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 308, + 197, + 545, + 228 + ], + "type": "text", + "content": "[31] T. Salimans and J Ho. Progressive distillation for fast sampling of diffusion models. International Conference on Learning Representations, 2022." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 230, + 545, + 282 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 230, + 545, + 282 + ], + "spans": [ + { + "bbox": [ + 308, + 230, + 545, + 282 + ], + "type": "text", + "content": "[32] Uriel Singer, Adam Polyak, Thomas Hayes, Xi Yin, Jie An, Songyang Zhang, Qiyuan Hu, Harry Yang, Oron Ashual, Oran Gafni, et al. Make-a-video: Text-to-video generation without text-video data. arXiv preprint arXiv:2209.14792, 2022." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 286, + 545, + 327 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 286, + 545, + 327 + ], + "spans": [ + { + "bbox": [ + 308, + 286, + 545, + 327 + ], + "type": "text", + "content": "[33] Jianlin Su, Yu Lu, Shengfeng Pan, Ahmed Murtadha, Bo Wen, and Yunfeng Liu. Roformer: Enhanced transformer with rotary position embedding. arXiv preprint arXiv:2104.09864, 2021." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 331, + 545, + 373 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 331, + 545, + 373 + ], + "spans": [ + { + "bbox": [ + 308, + 331, + 545, + 373 + ], + "type": "text", + "content": "[34] Guy Tevet, Brian Gordon, Amir Hertz, Amit H. Bermano, and Daniel Cohen-Or. Motionclip: Exposing human motion generation to clip space. European Conference on Computer Vision (ECCV), 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 376, + 545, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 376, + 545, + 407 + ], + "spans": [ + { + "bbox": [ + 308, + 376, + 545, + 407 + ], + "type": "text", + "content": "[35] Guy Tevet, Sigal Raab, Brian Gordon, Yonatan Shafir, Amit H Bermano, and Daniel Cohen-Or. Human motion diffusion model. arXiv preprint arXiv:2209.14916, 2022." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 410, + 545, + 462 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 410, + 545, + 462 + ], + "spans": [ + { + "bbox": [ + 308, + 410, + 545, + 462 + ], + "type": "text", + "content": "[36] Sijie Yan, Zhizhong Li, Yuanjun Xiong, Huahan Yan, and Dahua Lin. Convolutional sequence generation for skeleton-based action synthesis. Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 4393-4401, 2019." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 465, + 545, + 508 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 465, + 545, + 508 + ], + "spans": [ + { + "bbox": [ + 308, + 465, + 545, + 508 + ], + "type": "text", + "content": "[37] Hongwen Zhang, Yating Tian, Yuxiang Zhang, Mengcheng Li, Liang An, Zhenan Sun, and Yebin Liu. Pymaf-x: Towards well-aligned full-body model regression from monocular images. arXiv preprint arXiv:2207.06400, 2022." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 510, + 545, + 552 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 510, + 545, + 552 + ], + "spans": [ + { + "bbox": [ + 308, + 510, + 545, + 552 + ], + "type": "text", + "content": "[38] Mingyuan Zhang, Zhongang Cai, Liang Pan, Fangzhou Hong, Xinying Guo, Lei Yang, and Ziwei Liu. Motiondiffuse: Text-driven human motion generation with diffusion model. arXiv preprint arXiv:2208.15001, 2022." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 555, + 545, + 597 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 555, + 545, + 597 + ], + "spans": [ + { + "bbox": [ + 308, + 555, + 545, + 597 + ], + "type": "text", + "content": "[39] Yifei Zhang, Rania Briq, Julian Tanke, and Juergen Gall. Adversarial synthesis of human pose from text. 42nd DAGM German Conference of Pattern Recognition, pages 145-158, 2021." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 600, + 545, + 642 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 600, + 545, + 642 + ], + "spans": [ + { + "bbox": [ + 308, + 600, + 545, + 642 + ], + "type": "text", + "content": "[40] Rui Zhao, Hui Su, and Qiang Ji. Bayesian adversarial human motion synthesis. Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 6224-6233, 2020." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 644, + 545, + 687 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 644, + 545, + 687 + ], + "spans": [ + { + "bbox": [ + 308, + 644, + 545, + 687 + ], + "type": "text", + "content": "[41] Xingran Zhou, Siyu Huang, Bin Li, Yingming Li, Jiachen Li, and Zhongfei Zhang. Text guided person image synthesis. Proceedings IEEE Conf. on Computer Vision and Pattern Recognition (CVPR), 2019." + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "text", + "content": "15048" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/3c32b216-e73e-471f-8cad-0ce51b8a9a7c_content_list.json b/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/3c32b216-e73e-471f-8cad-0ce51b8a9a7c_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..980b12b001742173ec0dc802244852aa7e03dc32 --- /dev/null +++ b/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/3c32b216-e73e-471f-8cad-0ce51b8a9a7c_content_list.json @@ -0,0 +1,2065 @@ +[ + { + "type": "text", + "text": "Make-It-3D: High-Fidelity 3D Creation from A Single Image with Diffusion Prior", + "text_level": 1, + "bbox": [ + 76, + 152, + 898, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Junshu Tang $^{1\\dagger}$ Tengfei Wang $^{2\\dagger}$ Bo Zhang $^{3‡}$ Ting Zhang $^{3}$", + "bbox": [ + 233, + 202, + 733, + 222 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Ran Yi $^{1}$ Lizhuang Ma $^{1\\ddagger}$ Dong Chen $^{3}$", + "bbox": [ + 333, + 223, + 656, + 239 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{1}$ Shanghai Jiao Tong University $^{2}$ HKUST $^{3}$ Microsoft Research", + "bbox": [ + 220, + 241, + 750, + 260 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "https://make-it-3d.github.io/", + "bbox": [ + 310, + 263, + 656, + 280 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/e54bedeb393467444c8b6236dc07517aec8c9ad89da743d7aa84311408eceb5c.jpg", + "image_caption": [ + "Reference" + ], + "image_footnote": [], + "bbox": [ + 81, + 287, + 189, + 452 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/d6988a0e37b398c91d743993ae325f8abaf3009b5cd63f6585e4ddaba4694c33.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 202, + 292, + 274, + 372 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/06d8e89be7e724c061996062c71feb68bbecd45286463d1415674c6c1804fa61.jpg", + "image_caption": [ + "Normal" + ], + "image_footnote": [], + "bbox": [ + 189, + 378, + 292, + 452 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/c8ddbe1d4ca6ed848a8c7d2d8f64ec292e21e007c1f295d9ef81a729ad6b266e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 308, + 292, + 377, + 372 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/7315f1d333501f5ee13361beca23f10de0377066f33f35bbcefc56c6a42d8850.jpg", + "image_caption": [ + "Figure 1: Make-It-3D can create high-fidelity 3D content from only a single image. We show the normal map and novel-view renderings of created 3D content, showcasing fine geometry and faithful textures with stunning quality at novel views." + ], + "image_footnote": [], + "bbox": [ + 294, + 378, + 398, + 453 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/deee086095831a77801779b79f040b80ab1e5dd32ad409e107ad8a56e47989cb.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 410, + 292, + 475, + 372 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/46467de6d7a713ed4f9f698b7fdf55131b9076b7319b701e60af864fa2169988.jpg", + "image_caption": [ + "Novel Views" + ], + "image_footnote": [], + "bbox": [ + 398, + 380, + 500, + 453 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/c44196c384e8057e4868b8725f5fcc8ed870cb91b7156a49cfb588d89d497ee2.jpg", + "image_caption": [ + "Reference" + ], + "image_footnote": [], + "bbox": [ + 498, + 287, + 607, + 452 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/b466c4cbe7820bf5365c701cd8f1b6e36bd3fedfa392a00c24a7abb50d45a98c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 622, + 287, + 679, + 372 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/7b449617522578647040ecfede2f1e60e4035daa8dcc27830f52bc386266f428.jpg", + "image_caption": [ + "Normal" + ], + "image_footnote": [], + "bbox": [ + 617, + 372, + 697, + 452 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/1528522dda3176fdd420078451dc2aafc08d8debb7c77d0e3f117de9112d6c53.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 705, + 289, + 759, + 372 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/8ea39c7950b4dc4d78171a37214866f44d905eec2216782355e74c31012ec1d8.jpg", + "image_caption": [ + "Novel Views" + ], + "image_footnote": [], + "bbox": [ + 702, + 372, + 782, + 452 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/4b4ac5070eafd52ae7825894c666cd449c231a143244024f4b022565aa462d14.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 792, + 287, + 843, + 372 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/91113be4f7afec537cc6ef0069c12164fed42fd03dcaeb032e41fa4b02d48104.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 784, + 375, + 885, + 452 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 510, + 313, + 526 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In this work, we investigate the problem of creating high-fidelity 3D content from only a single image. This is inherently challenging: it essentially involves estimating the underlying 3D geometry while simultaneously hallucinating unseen textures. To address this challenge, we leverage prior knowledge from a well-trained 2D diffusion model to act as 3D-aware supervision for 3D creation. Our approach, Make-It-3D, employs a two-stage optimization pipeline: the first stage optimizes a neural radiance field by incorporating constraints from the reference image at the frontal view and diffusion prior at novel views; the second stage transforms the coarse model into textured point clouds and further elevates the realism with diffusion prior while leveraging the high-quality textures from the reference image. Extensive experiments demonstrate that our method outperforms prior works by a large margin, resulting in faithful reconstructions and impressive visual quality. Our method presents the first attempt to achieve high-quality 3D creation from a single image for general objects and enables various applications such as text-to-3D creation and texture editing.", + "bbox": [ + 73, + 532, + 472, + 849 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 501, + 510, + 630, + 526 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Given a single image as in Figure 1, how would the object portrayed in the image look like from a different perspective? Humans possess an innate ability to effortlessly imagine 3D geometry and hallucinate the appearance of novel views with a glance at the picture based on their prior knowledge about the world. In this work, we aim to achieve a similar goal: creating high-fidelity 3D content from a real or artificially generated single image. This will open up new avenues for artistic expression and creativity, such as bringing 3D effects to the fantasy images given by the cutting-edge 2D generative models like Stable Diffusion [38]. By offering a more accessible and automated way to create visually stunning 3D content, we hope to engage a broader audience with the world of 3D modeling with ease.", + "bbox": [ + 496, + 537, + 890, + 748 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The creation of 3D objects from a single image presents a significant challenge due to the limited information that can be inferred from a single viewpoint. One categories of works aim to produce 3D photo effect [28, 41, 11, 47] in the manner of image-based rendering or single-view 3D reconstruction with neural rendering [54, 56, 37]. However, these methods often struggle with reconstructing fine geometry and fall short of rendering in large views. Another line of research [26, 51, 59, 55] projects the input image into the latent space of the pretrained 3D-aware generative networks.", + "bbox": [ + 496, + 750, + 892, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "$\\dagger$ Work is done during the internship at Microsoft Research.", + "bbox": [ + 94, + 875, + 408, + 887 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "$\\ddagger$ Corresponding authors.", + "bbox": [ + 96, + 887, + 225, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "22819", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Despite their impressive performance, the existing 3D generative networks mainly model objects from a specific class and are therefore incapable of handling general 3D objects. In our case, we aim for general 3D creation from an arbitrary image, yet constructing a sufficiently large and diverse dataset for estimating the novel views or building a powerful 3D foundation model for general objects remains insurmountable.", + "bbox": [ + 75, + 90, + 472, + 210 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Unlike the scarcity of 3D models, images are much more readily available, and recent advancements in diffusion models have sparked a revolution in 2D image generation [34, 39, 38, 52, 4]. Interestingly, we observed that well-trained image diffusion models can generate images under various views, which implies that they have already incorporated 3D knowledge. This has motivated us to explore the possibility of cultivating prior knowledge in a 2D diffusion model to reconstruct 3D objects. With diffusion prior, we propose Make-It-3D, a two-stage 3D content creation method that can generate a high-fidelity 3D object with superior quality from only one image.", + "bbox": [ + 75, + 214, + 472, + 397 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In the first stage, we leverage diffusion prior to optimize a neural radiance field (NeRF) [23] by applying score distillation sampling (SDS) [32], and constrain this optimization with reference-view supervision. Different from prior text-to-3D works [32, 18, 22], we focus on image-based 3D creation so that we need to prioritize the faithfulness to the reference image. However, we observed that while 3D models generated with SDS match text prompts well, they often fail to align faithfully with reference images since textual descriptions do not capture all object details. To address this issue, we go beyond SDS by simultaneously maximizing the image-level similarity between the reference and the novel view rendering denoised by a diffusion model. Also, as images inherently capture more geometry-related information than textual descriptions, we can thus incorporate the depth of the reference image as an extra geometry prior to alleviate the shape ambiguity of NeRF optimization.", + "bbox": [ + 75, + 398, + 472, + 656 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "While the first stage generates a coarse model with plausible geometry, its appearance often deviates from the quality of the reference, exhibiting over-smooth textures and saturated colors [32]. This has limited its overall realism, and it is imperative to further bridge the gap between coarse model and reference image. As texture is more critical than geometry for human perception in the context of high-quality rendering, we choose to prioritize texture enhancement in the second stage, while inheriting the geometry from the first stage. We refine the model by leveraging the availability of ground-truth textures for regions that are observable in the reference image. To achieve this, we export the coarse NeRF model to textured point clouds and project reference textures onto their corresponding areas in the point clouds. We then utilize diffusion prior to enhance the texture of the remaining points by jointly optimizing", + "bbox": [ + 75, + 659, + 472, + 902 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "the point feature and a point cloud renderer, resulting in a clearly improved texture of the generated 3D model.", + "bbox": [ + 496, + 90, + 890, + 121 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "With diffusion prior as multi-view supervision, our approach can be applied to general objects without being limited to specific categories. To evaluate the method, we create a benchmark consisting of 400 images including both real images and generated images from 2D diffusion. We evaluate the proposed method on public DTU dataset [1] and our benchmark, and extensive experiments show a clear improvement over previous works. Furthermore, our method enables a range of applications beyond image-to-3D creation such as texture editing and high-quality text-to-3D creation. Our main contributions are summarized as:", + "bbox": [ + 496, + 121, + 893, + 286 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose Make-It-3D, a framework to create a high-fidelity 3D object from a single image, using a 2D diffusion model as 3D-aware prior. It does not require multi-view images for training and can be applied to any input image, whether it is real or generated.", + "- With a two-stage creation scheme, Make-It-3D represents the first work to achieve high-fidelity 3D creation for general objects. The resulting 3D models exhibit detailed geometry and realistic textures that accurately conform to the reference images.", + "- Beyond image-to-3D creation, our method enables multiple applications such as high-quality text-to-3D creation and texture editing." + ], + "bbox": [ + 517, + 287, + 890, + 483 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 497, + 640, + 513 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Novel view synthesis from a few images. Early attempts [14, 6, 45, 31] usually require dense observations of a scene from uniformly sampled poses. Recent emergence of implicit representations [42, 23] significantly advances the synthesis quality of novel views, whereas they tend to find a degenerate solution when given only very few input views. To enable novel view from sparse input views, a growing body of works [20, 46, 27] hence turn to extra prior knowledge as additional regularizations. PixelNeRF [59] predicts a continuous neural representation conditioned on the input images rather than only leveraging input views for supervision. DietNeRF [10] penalizes a semantic consistency loss by minimizing distance between CLIP [33] features of different views. With recent rapid progress of diffusion models, 3DiM [53] introduces a pose-conditional diffusion model that generates a novel view conditioned on a source view and a target pose. RenderDiffusion [3] presents a diffusion model for 3D generation that incorporates a triplane rendering mode into the denoiser.", + "bbox": [ + 496, + 523, + 890, + 809 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Single-image 3D photography. Synthesizing novel views from a single image is quite challenging as it is a highly ill-posed problem, requiring precise geometry estimation and disocclusion of both geometry and texture. Increasing effort has been dedicated to this problem [62, 7, 19, 29, 31, 36, 28, 44], many of which can only handle specific types. Among", + "bbox": [ + 496, + 810, + 893, + 901 + ], + "page_idx": 1 + }, + { + "type": "footer", + "text": "22820", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/7d774c4c5614db15c5362007b10d97d916661e68ae59ce0811427f18556af359.jpg", + "image_caption": [ + "1. Coarse Stage", + "Reference" + ], + "image_footnote": [], + "bbox": [ + 117, + 111, + 261, + 220 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/4593f30bc501fcd83b611a5c949cd88093b26139172d144ed030f4bb4a496634.jpg", + "image_caption": [ + "Neural Radiance Field" + ], + "image_footnote": [], + "bbox": [ + 290, + 106, + 439, + 214 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/d8d9f51668e36cb6a078665b44ec8697780ff6c4c010b9ea84f5da4d7e386fb0.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 454, + 143, + 483, + 157 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/bb8be0325ef351153c5332449b2a77a15c68becfaee3d7a7b9d862a0be6ff756.jpg", + "image_caption": [ + "Novel" + ], + "image_footnote": [], + "bbox": [ + 449, + 189, + 480, + 207 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/2c38c99e723df4fcfbb294b96af57eedf2b7a181f62f923ada079a2ed5ff1ecd.jpg", + "image_caption": [ + "Reference" + ], + "image_footnote": [], + "bbox": [ + 488, + 99, + 552, + 159 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/d29f64a74478541c3423fc56a17e6a485f568ba8ded840576ea2e279f61a303f.jpg", + "image_caption": [ + "view", + "views", + "A brown teddy bear sitting on a ground." + ], + "image_footnote": [], + "bbox": [ + 491, + 167, + 558, + 232 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/823a480f4417fbd883ff5da354595ff480597c601dbb23141667a9e92f715c69.jpg", + "image_caption": [ + "$\\mathcal{L}_{ref}, \\mathcal{L}_{depth}$" + ], + "image_footnote": [], + "bbox": [ + 558, + 101, + 620, + 159 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/b57e40bb396b9b7ceb0c48c3f46ec07eb1505c26b7a1224cf96318c237867545.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 563, + 167, + 629, + 233 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/05fb9987fe16058162735ea7722eafa54434db1ed553242514b073246989dd1e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 633, + 132, + 674, + 145 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/a9c7c4e002951609e3fcf1df9fbe116a7abc06333719a8584cd93622c26fd75a.jpg", + "image_caption": [ + "Estimated", + "Depth" + ], + "image_footnote": [], + "bbox": [ + 697, + 97, + 779, + 160 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/3c577e15e791eec6d36cd64ea1af85ca419e68fc15fbec4265d02e27bd1f6c2f.jpg", + "image_caption": [ + "Masked", + "Reference" + ], + "image_footnote": [], + "bbox": [ + 787, + 103, + 857, + 162 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/845a25496e250705aeaf72b1d3b2515720a2b6262aa0a7b564225c5045527477.jpg", + "image_caption": [ + "2. Refine Stage", + "Image Caption Model" + ], + "image_footnote": [], + "bbox": [ + 142, + 305, + 225, + 369 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/d4b886cfe4224543edf80ae17a93c703c4d6fe8816392eba84a6b88e6a3420b3.jpg", + "image_caption": [ + "Figure 2: Overview architecture. We propose a two-stage framework for creating a high-quality 3D model from a reference image with diffusion prior (Sec. 3.1). At the coarse stage, we optimize a NeRF for reconstructing the geometry of the reference image (Sec. 3.2). We further build textured point clouds from NeRF and the reference image, and jointly optimize the texture of invisible points and a learnable deferred renderer to generate realistic and view-consistent textures (Sec. 3.3)." + ], + "image_footnote": [], + "bbox": [ + 143, + 371, + 227, + 434 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/2caf905e558ed575170d96a958fe7fd2f966219bed7d7357b5dc26682bde9913.jpg", + "image_caption": [ + "Invisible Points", + "#", + "#", + "Textured Point Clouds" + ], + "image_footnote": [], + "bbox": [ + 325, + 310, + 437, + 415 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/f6a4055fb428f0e0099ad9a27f22ddd56b49ba8895c347752ce93e838ab6d98a.jpg", + "image_caption": [ + "#" + ], + "image_footnote": [], + "bbox": [ + 454, + 339, + 467, + 345 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/ebd11aedfb73f6f632ced0e7d7e00415ea6fb13d7f5e433b8b68e24578864de9.jpg", + "image_caption": [ + "XX", + "Descriptors" + ], + "image_footnote": [], + "bbox": [ + 454, + 347, + 468, + 356 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/1f924942d4ec7baea6a12190aa438f2b4563f4ae640fddceb162d6df64f89704.jpg", + "image_caption": [ + "Z-buffer & Rasterization", + "Deferred Renderer" + ], + "image_footnote": [], + "bbox": [ + 575, + 303, + 705, + 433 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/94ea0028c0a1a7f7a0422a876bac7a8002d8c38d97f7271bc6c368aa0a088ba8.jpg", + "image_caption": [ + "Enhanced Output" + ], + "image_footnote": [], + "bbox": [ + 709, + 295, + 849, + 426 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "them, a number of methods rely on layered representations such as layered depth images [40, 48, 41] and multi-plane images (MPIs) [43, 47, 17, 8]. For example, [47] predicts MPIs for view synthesis from single image without requiring ground truth 3D. [41] generates a 3D photo from a given RGB-D input through layered depth image with inpainted color and depth. Yet such a solution is limited by the number of planes and sensitive to discontinuities. Subsequent efforts generalize MPIs to continuous 3D representations such as NeRF [15] and latent 3D point cloud [54].", + "bbox": [ + 75, + 526, + 468, + 678 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Lift 2D pretrained model to 3D. With the emergence of recent advances in modeling natural image manifold, how to exploit such powerful 2D pretrained model to recover 3D object structure has received considerable research interest. [30] attempts to reconstruct the 3D shape using pretrained 2D GANs. Subsequently, some works [9, 13, 24] explore zero-shot text-guided 3D content creation utilizing the guidance from CLIP [33]. Recent efforts such as DreamFusion [32], Magic3D [18] and Score Jacobian Chaining [50] explore text-to-3D generation by exploiting a score distillation sampling (SDS) loss derived from a 2D text-to-image diffusion model instead, showing impressive results. LatentNeRF [22] proposes to use a shape prior to guide and assist the 3D generation directly in the latent space", + "bbox": [ + 75, + 688, + 470, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "of the diffusion model. Prior works NeuralLift-360 [57] and NeRDi [5] also leverage the generative prior for 3D reconstruction from a single view. Yet the reconstructed 3D model has limited quality and is poorly aligned with the input image. In contrast, we propose a two-stage 3D synthesis framework with a relaxed SDS loss, yielding high-quality 3D representation faithful to the given input image.", + "bbox": [ + 496, + 526, + 890, + 633 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Method", + "text_level": 1, + "bbox": [ + 500, + 647, + 589, + 662 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Generating novel views for general scenes or objects from only a single image is inherently challenging due to the difficulty of inferring both geometry and missing texture. We therefore tackle this challenge by cultivating the dark knowledge of pretrained 2D diffusion models. Specifically, given an input image $\\pmb{x}$ , we first hallucinate its underlying 3D representation, neural radiance field (NeRF), whose rendering appears as a plausible sample to a pretrained denoising diffusion model, and we constrain this optimization process with the texture and depth supervision at the reference view. To further improve the rendering realism, we keep the learned geometry and enhance the textures with the reference image. As such, in the second stage, we lift the input image to textured point clouds and focus on refining the color of the points occluded in the reference view.", + "bbox": [ + 496, + 674, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "22821", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We leverage prior knowledge of the text-to-image generative model and the text-image contrastive model for both stages. In this way, we achieve a faithful 3D representation of the input image with restored high-fidelity texture and geometry. The proposed two-stage 3D learning framework is illustrated in Figure 2. We will subsequently brief the preliminaries and then detail our method.", + "bbox": [ + 75, + 90, + 472, + 196 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.1. Preliminaries", + "text_level": 1, + "bbox": [ + 76, + 205, + 218, + 220 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Recent findings show that pretrained 2D generative models offer rich 3D geometry knowledge for their 2D generation samples. Notably, DreamFusion [32] uses a text-to-image diffusion model to guide the optimization of the 3D representation. Let $\\mathcal{G}_{\\theta}(\\beta)$ be the rendered image at the given viewpoint $\\beta$ , where $\\mathcal{G}$ is the differentiable rendering function for the 3D representation parameterized by $\\theta$ and is amenable to choice. DreamFusion optimizes the neural radiance field such that its multi-view renderings look like high-quality samples from a frozen diffusion model.", + "bbox": [ + 75, + 229, + 468, + 378 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Specifically, a diffusion model $\\epsilon_{\\phi}$ introduces a random amount of noise $\\epsilon$ to the rendered image $\\pmb{x}_0 \\coloneqq \\mathcal{G}_{\\theta}(\\beta)$ at different timestep $t$ , i.e., $\\pmb{x}_t = \\alpha_t \\pmb{x}_0 + \\sigma_t \\pmb{\\epsilon}$ , where $\\epsilon \\sim \\mathcal{N}(\\mathbf{0}, \\mathbf{I})$ ; $\\alpha_t$ and $\\sigma_t$ define a noise schedule whose log signal-to-noise ratio $\\lambda_t = \\log[\\alpha_t^2 / \\sigma_t^2]$ linearly decreases with the timestep $t$ . A pretrained text-conditioned diffusion model is trained to reverse this noising process given the text embedding $\\pmb{y}$ . To optimize the 3D representation parameters to render images as close as good generation samples, a score distillation sampling (SDS) loss $\\mathcal{L}_{\\mathrm{SDS}}$ is introduced to push rendered images toward higher density region conditioned on the text embedding. Specifically, $\\mathcal{L}_{\\mathrm{SDS}}$ computes the difference of predicted noise and the added noise as per-pixel gradient which is used to update the scene parameters, i.e.,", + "bbox": [ + 75, + 380, + 472, + 592 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\nabla_ {\\theta} \\mathcal {L} _ {\\mathrm {S D S}} (\\phi , \\mathcal {G} _ {\\theta}) = \\mathbb {E} _ {t, \\epsilon} \\left[ w (t) \\left(\\epsilon_ {\\phi} \\left(\\boldsymbol {x} _ {t}; \\boldsymbol {y}, t\\right) - \\epsilon\\right) \\frac {\\partial \\boldsymbol {x}}{\\partial \\theta} \\right], \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 86, + 599, + 468, + 636 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $w(t)$ is a weight function of different noise levels. It can be proved that this loss essentially measures the similarity between the image and the text prompt. The diffusion model acts as a critic and the gradient of $\\mathcal{L}_{\\mathrm{SDS}}$ will not be back-propagated through the diffusion network, resulting in efficient computation. As training proceeds, the NeRF parameters are updated during which the 3D object gradually reveals its texture and geometry. In practice, it is found that using a diffusion model with a strong classifier-free guidance leads to higher-quality 3D samples.", + "bbox": [ + 75, + 643, + 468, + 794 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "While DreamFusion uses the Imagen [39] to reverse the noising process at the pixel level, we use the publicly available Stable Diffusion [38] that models the latent space of the VQ-VAE [49] with an encoder $\\mathcal{E}$ and a decoder $\\mathcal{D}$ . Hence, the used diffusion model digests the latent $z_0 \\coloneqq \\mathcal{E}(\\mathcal{G}_{\\theta}(\\beta))$ and the reconstructed latent $\\hat{z}_0$ can be mapped to image space through $\\hat{\\boldsymbol{x}} = \\mathcal{D}(\\hat{z}_0)$ .", + "bbox": [ + 75, + 795, + 470, + 901 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/fbf2adf1b329cc31af3ac5e4dce2323c42cbb509632637866c1b95eea0f08402.jpg", + "image_caption": [ + "Figure 3: Analysis on the coarse stage. Baseline is a naive solution using only $\\mathcal{L}_{\\mathrm{SDS}}$ and $\\mathcal{L}_{\\mathrm{ref}}$ , and it does not match the reference well. With $\\mathcal{L}_{\\mathrm{CLIP-D}}$ , the result aligns better with the reference. The depth prior further improves faithfulness." + ], + "image_footnote": [], + "bbox": [ + 500, + 88, + 890, + 185 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Coarse Stage: Single-view 3D Reconstruction", + "text_level": 1, + "bbox": [ + 498, + 273, + 883, + 290 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "As the first stage, we reconstruct a coarse NeRF from the single reference image $\\pmb{x}$ with the diffusion prior constraining the novel views. Our optimization is expected to meet the following requirements simultaneously: 1) the optimized 3D representation should closely resemble the rendering appearance of the input observation $\\pmb{x}$ at the reference view; 2) the novel view renderings should demonstrate consistent semantics with the input and appear as plausible as possible; 3) the generated 3D model should exhibit compelling geometry. In view of these, we randomly sample the camera poses around the reference view and enforce constraints upon the rendered images $\\mathcal{G}_{\\theta}$ for both the reference view and unseen views.", + "bbox": [ + 496, + 297, + 890, + 492 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Reference view per-pixel loss. To encourage consistent appearance with the input image, we penalize the pixel-wise difference between the rendering and the input image at the reference view $\\beta_{\\mathrm{ref}}$ :", + "bbox": [ + 496, + 494, + 890, + 554 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {r e f}} = \\left\\| \\boldsymbol {x} \\odot \\boldsymbol {m} - \\mathcal {G} _ {\\theta} \\left(\\beta_ {\\text {r e f}}\\right) \\right\\| _ {1}. \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 594, + 563, + 890, + 580 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Here we apply the foreground matting mask $\\pmb{m}$ to segment out the foreground as we empirically find that this eases the geometry reconstruction, which conforms to [58].", + "bbox": [ + 496, + 589, + 890, + 635 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Diffusion prior. Optimizing with the aforementioned losses can be unstable and may lead to implausible results, due to the ill-posed nature of the problem. In order to encourage semantically plausible results, additional constraints are needed on the novel view rendering. To tackle this challenge, we resort to the diffusion prior. Prior works on text-to-3D [32, 18] applied $\\mathcal{L}_{\\mathrm{SDS}}$ to leverage text-conditioned diffusion models as 3D-aware prior. To utilize $\\mathcal{L}_{\\mathrm{SDS}}$ in our case, we use an image captioning model [16], to generate a detailed text description $y$ for the reference image. With the text prompt $y$ , we can perform the SDS on the latent space of Stable Diffusion,", + "bbox": [ + 496, + 635, + 890, + 816 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\nabla_ {\\theta} \\mathcal {L} _ {\\mathrm {S D S}} (\\phi , \\mathcal {G} _ {\\theta}) = \\mathbb {E} _ {t, \\epsilon} \\left[ w (t) \\left(\\epsilon_ {\\phi} \\left(\\boldsymbol {z} _ {t}; \\boldsymbol {y}, t\\right) - \\epsilon\\right) \\frac {\\partial \\boldsymbol {z}}{\\partial \\boldsymbol {x}} \\frac {\\partial \\boldsymbol {x}}{\\partial \\theta} \\right], \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 506, + 824, + 890, + 869 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where the noisy latent $\\mathbf{z}_t$ is obtained from a novel view rendering $\\mathbf{x}$ by Stable Diffusion encoder.", + "bbox": [ + 496, + 869, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "footer", + "text": "22822", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/26f77c84ab863be0135e9b89c18a1d55a9552c2754e805f517d3606f57f445ca.jpg", + "image_caption": [ + "Figure 4: $360^{\\circ}$ object reconstruction from real images." + ], + "image_footnote": [], + "bbox": [ + 81, + 88, + 155, + 213 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/dbf70d1db83d4527533f4ccd8f62d019ffeecaa77d68edad489c0fd85ffdff66.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 165, + 88, + 225, + 213 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/a4cb6bc2e0b8f21893de5df3776fd5a67672e9957df9c4d06fba5f0f66bfb677.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 236, + 107, + 300, + 212 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/3b180ad83095ad02186250d25a705636024d2d71ba80b6f486f321f0d2b77f74.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 303, + 88, + 385, + 212 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/55e8c7f061168dbb1898b9fa4577ac3c7dee7584dbb9567a295a411fea9fb6a7.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 392, + 106, + 467, + 210 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "However, as discussed before, $\\mathcal{L}_{\\mathrm{SDS}}$ essentially measures the similarity between the image and the given text prompt. While $\\mathcal{L}_{\\mathrm{SDS}}$ can generate 3D models that are faithful to the text prompt, they do not align perfectly with the reference image (see baseline in Figure 3), since text prompts cannot capture all object details. We go beyond this by a diffusion CLIP loss, denoted as $\\mathcal{L}_{\\mathrm{CLIP-D}}$ , that additionally enforces the generated model to match the reference image:", + "bbox": [ + 75, + 258, + 468, + 380 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {C L I P - D}} (\\mathcal {X}, \\mathcal {G} _ {\\theta} (\\beta)) = - \\mathcal {E} _ {\\mathrm {C L I P}} (\\mathcal {X}) \\cdot \\mathcal {E} _ {\\mathrm {C L I P}} (\\hat {\\mathcal {X}} _ {0} (\\beta , t)), \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 91, + 387, + 468, + 405 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathcal{E}_{\\mathrm{CLIP}}(\\cdot)$ is a CLIP image encoder [33]. Rather than directly measuring CLIP loss on the rendered images $\\mathcal{G}_{\\theta}(\\beta)$ , we encode the novel view rendering $\\mathcal{G}_{\\theta}(\\beta)$ to noisy latent $z_{t}$ and then denoise it to a clean image $\\tilde{\\mathcal{X}}_0(\\beta, t)$ with 2D diffusion. By imposing the similarity loss on denoised images sampled from diffusion models, we encourage the rendering to align with the reference image, while resembling high-quality samples from a frozen diffusion.", + "bbox": [ + 75, + 411, + 468, + 531 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In detail, we do not optimize $\\mathcal{L}_{\\mathrm{CLIP - D}}$ and $\\mathcal{L}_{\\mathrm{SDS}}$ at the same time. We use $\\mathcal{L}_{\\mathrm{CLIP - D}}$ at small timesteps and switch to $\\mathcal{L}_{\\mathrm{SDS}}$ at large timesteps. More details and analysis are in the Supplement. Combining $\\mathcal{L}_{\\mathrm{SDS}}$ and $\\mathcal{L}_{\\mathrm{CLIP - D}}$ , our diffusion prior ensures that the resulting 3D model appears visually appealing and plausible while also conforming to the given image (see Figure 3).", + "bbox": [ + 75, + 532, + 468, + 637 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Depth prior. Nonetheless, even if the rendered image appears meaningful to the diffusion model, there still exists shape ambiguity that brings about issues such as sunken faces, over-flat geometry [32] or depth ambiguity (see Figure 3). We mitigate these by leveraging depth prior learned from abundant external images and directly enforcing the supervision in 3D. To be specific, we utilize an off-the-shelf single-view depth estimator [35] to estimate the depth $d$ for the input image. While the estimated depth may not accurately characterize the geometric detail, it suffices to ensure plausible geometry and resolve most of the ambiguity. To account for the inaccuracy and the scale mismatch in $d$ , akin to [5], we regularize the negative Pearson correlation between the estimated depth and the depth $d(\\beta_{\\mathrm{ref}})$ modeled by NeRF at the reference viewpoint, i.e.,", + "bbox": [ + 75, + 638, + 468, + 864 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {d e p t h}} = - \\frac {\\operatorname {C o v} \\left(d \\left(\\beta_ {\\text {r e f}}\\right) , d\\right)}{\\operatorname {V a r} \\left(d \\left(\\beta_ {\\text {r e f}}\\right)\\right) \\operatorname {V a r} (d)}, \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 166, + 869, + 468, + 905 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/ab569120f2bab3c1c7de48391a26dbab8ddb9afb5a180b49b6c85f922573e99c.jpg", + "image_caption": [ + "Figure 5: Illustration of textured point cloud building. We aim at building dense points and texturing visible points using reference image, and invisible points from NeRF." + ], + "image_footnote": [], + "bbox": [ + 501, + 88, + 890, + 239 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathrm{Cov}(\\cdot)$ denotes the covariance, $\\mathrm{Var}(\\cdot)$ computes the standard deviation. With this regularization, the NeRF depth estimation is encouraged to be linearly correlated with the depth prior.", + "bbox": [ + 496, + 306, + 890, + 368 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Overall training. The overall loss can be formulated as a combination of $\\mathcal{L}_{\\mathrm{ref}}$ , $\\mathcal{L}_{\\mathrm{SDS}}$ , $\\mathcal{L}_{\\mathrm{CLIP-D}}$ and $\\mathcal{L}_{\\mathrm{depth}}$ . To stabilize the optimization process, we adopt a progressive training strategy, where we start with a narrow range of views near the reference view and gradually expand the range during training. With progressive training, we can achieve a $360^{\\circ}$ reconstruction of an object, as shown in Figure 4.", + "bbox": [ + 496, + 368, + 890, + 474 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.3. Refine Stage: Neural Texture Enhancement", + "text_level": 1, + "bbox": [ + 500, + 484, + 870, + 500 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "After the coarse stage, we obtained a 3D model with plausible geometry, but it often displays coarse textures that can bottleneck the overall quality in Figure 6. Further refinement is thus desired for high-fidelity 3D models. Given that humans are more discerning when it comes to texture quality than geometry, we prioritize texture enhancement while preserving the geometry of the coarse model.", + "bbox": [ + 496, + 507, + 890, + 612 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Our key insight for texture enhancement is that for a novel view, certain pixels can be observable in both the novel and reference views. Consequently, we can exploit this overlap to project the high-quality texture of the reference image onto the corresponding areas of the 3D representation. We then focus on enhancing the textures of regions that are occluded in the reference view.", + "bbox": [ + 496, + 614, + 890, + 717 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "While NeRF is a suitable representation in the coarse stage as it can handle topological changes continuously, projecting the reference image onto it is challenging. We thus opt to export the neural radiance field to an explicit representation, specifically point clouds. Compared to the noisy mesh exported by marching cube, point clouds offer a cleaner and more straightforward projection.", + "bbox": [ + 496, + 719, + 890, + 824 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Textured point cloud building. A naive attempt to build point clouds is to render multi-view RGBD images from NeRF and lift them to textured points in 3D space. However, we found this simple method leads to noisy point clouds due to the conflict among different views: a 3D point", + "bbox": [ + 496, + 825, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "22823", + "bbox": [ + 478, + 924, + 517, + 935 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/23e1283002c06d3509ca3c7e501a61071643f0fd5d1f7ac298add0ea93177e9c.jpg", + "image_caption": [ + "Figure 6: Visualization of neural texture enhancement. We project the reference textures to the coarse model and enhance the remaining regions to high-frequency details consistent with the reference. Best viewed with zoom-in." + ], + "image_footnote": [], + "bbox": [ + 81, + 87, + 171, + 238 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/0064eb298ac99a1797db5c3614d9cdfc828af6475530710b86a1b8e0a1c620c5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 176, + 88, + 238, + 237 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/28c8e40a82f7dbb0a1fd180b1141b4b8d51a058b4e9ea7966e11f52eee04055f.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 248, + 88, + 313, + 238 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/b5b20907eeaf38e9a96ded160117cb4d4b7f0427982cc9648212e2ef623392d9.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 316, + 88, + 388, + 238 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/640a42b89ce2436a79964101e526c1ae65be753033ac5cdf6dea04b168d815ce.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 392, + 88, + 465, + 238 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "may possess different RGB colors in NeRF rendering under different views [55]. We thus propose an iterative strategy to build clean point clouds from multi-view observations.", + "bbox": [ + 75, + 323, + 468, + 369 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "As in Figure 5, we first build point clouds from the reference view $\\beta_{\\mathrm{ref}}$ according to the rendered depth $\\mathcal{D}(\\beta_{\\mathrm{ref}})$ and alpha mask $M(\\beta_{\\mathrm{ref}})$ of NeRF,", + "bbox": [ + 75, + 369, + 468, + 415 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\nV \\left(\\beta_ {\\text {r e f}}\\right) = R _ {\\text {r e f}} K ^ {- 1} \\mathcal {P} \\left(\\mathcal {D} \\left(\\beta_ {\\text {r e f}}\\right) * M \\left(\\beta_ {\\text {r e f}}\\right)\\right), \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 129, + 429, + 468, + 446 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $R_{\\mathrm{ref}}$ and $K$ are the extrinsic and intrinsic matrices of the camera, and $\\mathcal{P}$ denotes depth-to-point projection. These points are visible under the reference view and thus colorized with ground-truth textures. For the projection of the remaining views $\\beta_{i}$ , it is important to avoid introducing points that overlap with existing points but have conflicting colors. To this end, we project the existing points $V(\\beta_{\\mathrm{ref}})$ to the novel view $\\beta_{i}$ to yield a mask indicating the presence of existing points. With this mask as guidance, we only lift those points $V(\\beta_{i})$ that have not been observed yet, as shown in Figure 5. These invisible points are then initialized with coarse textures from NeRF rendering $\\mathcal{G}(\\beta_{i})$ and integrated into the dense point clouds.", + "bbox": [ + 75, + 460, + 468, + 657 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Deferred point cloud rendering. So far, we have built a set of textured point clouds $V = \\{V(\\beta_{\\mathrm{ref}}), V(\\beta_1), \\dots, V(\\beta_N)\\}$ . Though $V(\\beta_{\\mathrm{ref}})$ already have high-fidelity textures projected from the reference image, the other points that are occluded in the reference view still suffer smooth textures from the coarse NeRF, as shown in Figure 6. To enhance the texture, we optimize the texture of the other points and constrain novel-view rendering with diffusion prior. Specifically, we optimize a 19-dimensional descriptor $F$ for each point, whose first three dimensions are initialized with the initial RGB colors. To avoid noisy colors and bleeding artifacts [2], we adopt a multi-scale deferred rendering scheme. In particular, given a novel view $\\beta$ , we rasterize the point cloud $\\mathbf{V}$ for $K$ times to obtain $K$ feature maps $I_i$ with varying sizes of $[W/2^i, H/2^i]$ , where $i \\in [0, K)$ . These feature maps are then concatenated and rendered into an image $\\mathbf{I}$", + "bbox": [ + 75, + 659, + 470, + 900 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/320c58fd42b6c3500f9fa038c3c30a89239309828917520b38f7e96ece55e715.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ViewsLPIPS↓Contextual↓CLIP↑
DietNeRF [10]30.18315.3464.90%
SinNeRF [56]10.20594.2873.24%
DreamFusion+ [32]10.40752.1582.81%
Point-E [26]1-2.2371.31%
3D-Photo [41]103.4387.65%
Ours-coarse10.14271.7487.50%
Ours-enhanced10.09081.5995.65%
", + "bbox": [ + 504, + 88, + 888, + 215 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/e002da114dd743fc6402672427069eb4567e76f476bf3bd0fb22d5d99491dfb6.jpg", + "table_caption": [ + "Table 1: Quantitative comparison on DTU. We compute LPIPS under the reference view, and other two metrics under novel views. LPIPS of Point-E is not reported due to the lack of a defined reference view." + ], + "table_footnote": [], + "table_body": "
LPIPS↓Contextual↓CLIP↑
DreamFusion+ [32]0.56493.0784.08%
Point-E [26]-5.3764.36%
Ours-coarse0.23541.9889.06%
Ours-enhanced0.07801.3395.12%
", + "bbox": [ + 529, + 281, + 862, + 368 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2: Quantitative comparison on the test benchmark.", + "bbox": [ + 508, + 371, + 880, + 385 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "using a U-Net renderer $\\mathcal{R}_{\\theta}$ [2] that is jointly optimized:", + "bbox": [ + 500, + 402, + 864, + 417 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\nI _ {i} (\\beta) = \\mathcal {S} (i, V, F, \\beta), i \\in [ 0, K),\n$$\n", + "text_format": "latex", + "bbox": [ + 562, + 429, + 790, + 446 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {I} (\\beta) = \\mathcal {R} _ {\\theta} \\left(I _ {0} (\\beta), I _ {1} (\\beta), \\dots , I _ {K - 1} (\\beta)\\right), \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 563, + 441, + 890, + 465 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $S$ is a differentiable point rasterizer. The objective of the texture enhancement process is similar to that of the geometry creation discussed in Sec. 3.2, but we additionally include a regularization term that penalizes large differences between the optimized texture and the initial texture. With the texture enhancement process, fine-detailed texture is generated on the occluded points.", + "bbox": [ + 500, + 474, + 890, + 580 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 500, + 595, + 632, + 612 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Implementation Details", + "text_level": 1, + "bbox": [ + 500, + 619, + 715, + 635 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "NeRF rendering. We use the multi-scale hash encoding from Instant-NGP [25] to implement the NeRF representation in the coarse optimization stage, which enables neural rendering at a computational cost. Similar to Instant-NGP, we maintain an occupancy grid to enable efficient ray sampling by skipping empty space. Additionally, we adopt several shading augmentations on the rendered images, such as Lambertian and normal shading, akin to [32].", + "bbox": [ + 496, + 643, + 890, + 763 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Point cloud rendering. For deferred rendering, we use a 2D U-Net architecture with gated convolutions [60]. The dimension of the point descriptor is 19, where the first 3 dimensions are initialized RGB colors and the remaining dimensions are randomly initialized. We also set a learnable descriptor for the background.", + "bbox": [ + 496, + 765, + 890, + 854 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Camera setting. Following the camera sampling method used in [32], we randomly sample novel views with a $75\\%$ probability and sample the pre-defined reference view with", + "bbox": [ + 496, + 854, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "22824", + "bbox": [ + 478, + 924, + 517, + 935 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/b29d69849552ba288a44102b49a494deaaa36e5028fa66d0b446221edd1ff428.jpg", + "image_caption": [ + "Figure 7: Qualitative comparison on the test benchmark with two diffusion-based 3D content creation models, Dreamfusion and Point-E. We show our results with high-fidelity geometry and texture. The results of Dreamfusion are from its website." + ], + "image_footnote": [], + "bbox": [ + 76, + 85, + 890, + 383 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/be88b9d2a005b48ff33408552c42bb60f9a21679ceeb1fbe3b4522725ffb05da.jpg", + "image_caption": [ + "Figure 8: Qualitative comparison of novel view synthesis on DTU with state of the arts. Our method generates sharper and more plausible details in both geometry and texture." + ], + "image_footnote": [], + "bbox": [ + 76, + 434, + 890, + 575 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "a $25\\%$ probability. We also randomly enlarge the FOV when rendering with NeRF, following [18].", + "bbox": [ + 75, + 627, + 468, + 657 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Score distillation sampling. We randomly sample $t$ from 0.2 to 0.6, and set $w(t)$ as a uniform weighting depending on the timestep. We also use classifier-free guidance with a guidance weight $\\omega : \\hat{\\epsilon}_{\\phi}(z_t; y, t) = (1 + \\omega)\\epsilon_{\\phi}(z_t; y, t) - \\omega \\epsilon_{\\phi}(z_t; t)$ . Our method aims to align the created 3D model with the input image, and we use a guidance weight $\\omega = 10$ . Training speed. We use Adam [12] with a learning rate of 0.001 for both stages. The coarse stage is trained for 5,000 iterations at a rendering resolution of $100 \\times 100$ . The refine stage then takes another 5,000 iterations at a rendering resolution of $800 \\times 800$ . The entire training process takes approximately 2 hours on a single Tesla 32GB V100 GPU.", + "bbox": [ + 75, + 657, + 468, + 838 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Test Benchmark. To the best of our knowledge, we are the first method focusing on high-fidelity 3D creation from an arbitrary image. So we build a test benchmark consisting of 400 images, comprising both real images and images gener-", + "bbox": [ + 75, + 839, + 468, + 901 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/cfda69fecdaf4fed94eaa7b1a8514ef2414c16ab197f6209b2b5cba75b996730.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Preference RateGeometry QualityTexture QualityFidelity to Input
Ours/DreamFusion+88.2%/11.8%95.6%/4.4%96.5%/3.5%
", + "bbox": [ + 509, + 625, + 880, + 657 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 3: Preference rate of geometry quality, texture quality, and fidelity to the input image.", + "bbox": [ + 500, + 660, + 890, + 691 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "ated by Stable Diffusion [38]. Each image in the benchmark is accompanied by a foreground alpha mask, an estimated depth map, and a text prompt. The text prompts for real images are obtained from an image caption model [16]. We will make this test benchmark publicly available.", + "bbox": [ + 496, + 712, + 890, + 789 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.2. Comparisons with the State of the Arts", + "text_level": 1, + "bbox": [ + 498, + 800, + 834, + 816 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Baselines. We compare our method with five representative baselines. 1) DietNeRF [10], a few-shot NeRF. We train it with three input views. 2) SinNeRF [56], a single-view NeRF method. 3) DreamFusion [32]. As it is originally conditioned on text prompts, we also modify it with image", + "bbox": [ + 496, + 824, + 890, + 901 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "22825", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/fdb1db10dd726034626928f6b704f9db1937de2efdf114b83d3bfdda716c4fbb.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 80, + 88, + 468, + 238 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/c9c001c947f2e50eb0c46dc1766dc2509c6b90ede199331059904a1856d7a1f6.jpg", + "image_caption": [ + "Figure 9: Make-It-3D enables high-fidelity 3D creation on real complex scenes.", + "Figure 10: Make-It-3D generates diverse and visually stunning 3D models given a text description." + ], + "image_footnote": [], + "bbox": [ + 78, + 276, + 467, + 463 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "reconstruction loss at the reference view, referred as Dream-Fusion+ for fair comparison. 4) Point-E [26], point cloud generation conditioned on image. 5) 3D-Photo [41], depth-based image warping and inpainting method.", + "bbox": [ + 76, + 518, + 468, + 579 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Qualitative comparison. We first compare our method with 3D generation baselines, where DreamFusion and DreamFusion+ leverage 2D diffusion as 3D prior and PointE is a 3D diffusion model. As shown in Figure 7, their generated models fail to align faithfully with the reference image and suffer smooth textures. In contrast, our method produces high-fidelity 3D models with fine geometry and realistic textures. Figure 8 shows additional comparison on novel view synthesis. SinNeRF and DietNeRF encounter difficulties in reconstructing complex objects due to the lack of multi-view supervision. 3D-Photo fails to reconstruct underlying geometry and produces visible artifacts in large views. In comparison, our method achieves remarkably faithful geometry and visually pleasing textures under novel views.", + "bbox": [ + 76, + 580, + 468, + 806 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Quantitative comparison. A compelling generated 3D model should closely resemble the input image at the reference view, and demonstrate consistent semantics with the reference under novel views. We evaluate these two aspects using the following metrics: 1) LPIPS [61], which assesses the reconstruction quality at the reference view, 2) context-", + "bbox": [ + 76, + 809, + 468, + 900 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/b235b34f868e43e6ec4d9f89e1bdf638b2b702ce1248534aeae001dc1700b358.jpg", + "image_caption": [ + "Figure 11: Make-It-3D achieves 3D-aware texture modification such as tattoo drawing and stylization." + ], + "image_footnote": [], + "bbox": [ + 522, + 87, + 870, + 329 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "tual distance [21], which measures pixel-level similarity between novel-view rendering and the reference, and 3) CLIP score [33], which evaluates the semantic similarity between the novel view and the reference. As shown in Table 1 and Table 2, our approach substantially outperforms baselines in terms of both reference-view and novel-view quality.", + "bbox": [ + 498, + 382, + 890, + 473 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "User study. In order to obtain the user's subjective evaluation of the plausibility of the results, we conduct a user study on 30 participants. In the study, we use 25 pairs of results generated by our method and Dreamfusion+, respectively. All results are presented side-by-side and in a random order to participants. Based on the ratings in Table 3, our method outperformed Dreamfusion+ in all aspects.", + "bbox": [ + 498, + 474, + 890, + 580 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Applications", + "text_level": 1, + "bbox": [ + 500, + 599, + 629, + 616 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Real scene modeling. As shown in Figure 9, Make-It-3D can successfully convert a single photo of a complex scene to a 3D model, such as buildings and landscapes. This empowers users to model a scene with ease, which could be difficult for some traditional 3D modeling techniques.", + "bbox": [ + 498, + 625, + 890, + 700 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "High-quality text-to-3D generation with diversity. Prior arts [32, 18] often produce models with limited diversity and excessively smooth textures. To perform high-quality text-to-3D creation, we first convert the text prompt to a reference image using 2D diffusion, and proceed with our image-based 3D creation method. As shown in Figure 10, Make-It-3D is capable of producing diverse examples from a text prompt that exhibit stunning quality.", + "bbox": [ + 498, + 702, + 890, + 823 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "3D-aware texture modification. Make-It-3D enables view-consistent texture editing by manipulating the reference image in the refine stage while freezing the geometry. Figure 11 shows that we can add a tattoo and apply stylization to the generated 3D model.", + "bbox": [ + 498, + 824, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "22826", + "bbox": [ + 478, + 924, + 517, + 935 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Conclusions", + "text_level": 1, + "bbox": [ + 76, + 90, + 204, + 104 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We introduce Make-It-3D, a novel two-stage method for creating high-fidelity 3D content from one single image. Leveraging diffusion prior as 3D-aware supervision, the generated 3D models exhibit faithful geometry and realistic textures with the diffusion CLIP loss and textured point cloud enhancement. Make-It-3D is applicable to general objects, empowering versatile fascinating applications. We believe our method takes a big step in extending the success of 2D content creation to 3D, providing users with a fresh 3D creation experience.", + "bbox": [ + 75, + 114, + 472, + 267 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "7. Acknowledgement", + "text_level": 1, + "bbox": [ + 76, + 282, + 256, + 301 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "The research is supported by National Natural Science Foundation of China (61972157, 72192821), Shanghai Municipal Science and Technology Major Project (2021SHZDZX0102), Shanghai Science and Technology Commission (21511101200), Shanghai Sailing Program (22YF1420300, 23YF1410500) and Young Elite Scientists Sponsorship Program by CAST (2022QNRC001).", + "bbox": [ + 75, + 309, + 468, + 416 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 431, + 174, + 448 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Henrik Aanaes, Rasmus Ramsbøl Jensen, George Vogiatzis, Engin Tola, and Anders Bjorholm Dahl. Large-scale data for multiple-view stereopsis. International Journal of Computer Vision, pages 1-16, 2016. 2", + "[2] Kara-Ali Aliev, Artem Sevastopolsky, Maria Kolos, Dmitry Ulyanov, and Victor Lempitsky. Neural point-based graphics. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XXII 16, pages 696-712. Springer, 2020. 6", + "[3] Titas Anciukevicius, Zexiang Xu, Matthew Fisher, Paul Henderson, Hakan Bilen, Niloy J Mitra, and Paul Guerrero. Renderdiffusion: Image diffusion for 3d reconstruction, inpainting and generation. arXiv preprint arXiv:2211.09869, 2022. 2", + "[4] Yogesh Balaji, Seungjun Nah, Xun Huang, Arash Vahdat, Jiaming Song, Karsten Kreis, Miika Aittala, Timo Aila, Samuli Laine, Bryan Catanzaro, Tero Karras, and Ming-Yu Liu. ediff-i: Text-to-image diffusion models with an ensemble of expert denoisers. ArXiv, abs/2211.01324, 2022. 2", + "[5] Congyue Deng, Chiyu Jiang, Charles R Qi, Xinchen Yan, Yin Zhou, Leonidas Guibas, Dragomir Anguelov, et al. Nerdi: Single-view nerf synthesis with language-guided diffusion as general image priors. arXiv preprint arXiv:2212.03267, 2022. 3, 5", + "[6] Steven J Gortler, Radek Grzesczuk, Richard Szeliski, and Michael F Cohen. The lumigraph. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, pages 43-54, 1996. 2", + "[7] Tewodros Habtegebrial, Kiran Varanasi, Christian Bailer, and Didier Stricker. Fast view synthesis with deep stereo vision. arXiv preprint arXiv:1804.09690, 2018. 2" + ], + "bbox": [ + 86, + 458, + 468, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[8] Yuxuan Han, Ruicheng Wang, and Jiaolong Yang. Single-view synthesis in the wild with learned adaptive multiplane images. In ACM SIGGRAPH 2022 Conference Proceedings, pages 1-8, 2022. 3", + "[9] Ajay Jain, Ben Mildenhall, Jonathan T Barron, Pieter Abbeel, and Ben Poole. Zero-shot text-guided object generation with dream fields. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 867-876, 2022. 3", + "[10] Ajay Jain, Matthew Tancik, and Pieter Abbeel. Putting nerf on a diet: Semantically consistent few-shot view synthesis. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 5885-5894, 2021. 2, 6, 7", + "[11] Varun Jampani, Huiwen Chang, Kyle Sargent, Abhishek Kar, Richard Tucker, Michael Krainin, Dominik Kaeser, William T Freeman, David Salesin, Brian Curless, et al. Slide: Single image 3d photography with soft layering and depth-aware inpainting. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 12518-12527, 2021. 1", + "[12] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014.7", + "[13] Han-Hung Lee and Angel X Chang. Understanding pure clip guidance for voxel grid nerf models. arXiv preprint arXiv:2209.15172, 2022. 3", + "[14] Marc Levoy and Pat Hanrahan. Light field rendering. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, pages 31-42, 1996. 2", + "[15] Jiaxin Li, Zijian Feng, Qi She, Henghui Ding, Changhu Wang, and Gim Hee Lee. Mine: Towards continuous depth spi with nerf for novel view synthesis. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 12578-12588, 2021. 3", + "[16] Junnan Li, Dongxu Li, Silvio Savarese, and Steven Hoi. Blip-2: Bootstrapping language-image pre-training with frozen image encoders and large language models. arXiv preprint arXiv:2301.12597, 2023. 4, 7", + "[17] Qinbo Li and Nima Khademi Kalantari. Synthesizing light field from a single image with variable mpi and two network fusion. ACM Trans. Graph., 39(6):229-1, 2020. 3", + "[18] Chen-Hsuan Lin, Jun Gao, Luming Tang, Towaki Takikawa, Xiaohui Zeng, Xun Huang, Karsten Kreis, Sanja Fidler, Ming-Yu Liu, and Tsung-Yi Lin. Magic3d: High-resolution text-to-3d content creation. arXiv preprint arXiv:2211.10440, 2022. 2, 3, 4, 7, 8", + "[19] Miaomiao Liu, Xuming He, and Mathieu Salzmann. Geometry-aware deep network for single-image novel view synthesis. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4616-4624, 2018. 2", + "[20] Stephen Lombardi, Tomas Simon, Jason Saragih, Gabriel Schwartz, Andreas Lehrmann, and Yaser Sheikh. Neural volumes: Learning dynamic renderable volumes from images. arXiv preprint arXiv:1906.07751, 2019. 2", + "[21] Roey Mechrez, Itamar Talmi, and Lihi Zelnik-Manor. The contextual loss for image transformation with non-aligned" + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "22827", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "data. In Proceedings of the European conference on computer vision (ECCV), pages 768-783, 2018. 8", + "[22] Gal Metzer, Elad Richardson, Or Patashnik, Raja Giryes, and Daniel Cohen-Or. Latent-nerf for shape-guided generation of 3d shapes and textures. arXiv preprint arXiv:2211.07600, 2022. 2, 3", + "[23] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021. 2", + "[24] Nasir Mohammad Khalid, Tianhao Xie, Eugene Belilovsky, and Tiberiu Popa. Clip-mesh: Generating textured meshes from text using pretrained image-text models. In SIGGRAPH Asia 2022 Conference Papers, pages 1-8, 2022. 3", + "[25] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Transactions on Graphics (ToG), 41(4):1-15, 2022. 6", + "[26] Alex Nichol, Heewoo Jun, Prafulla Dhariwal, Pamela Mishkin, and Mark Chen. Point-e: A system for generating 3d point clouds from complex prompts. arXiv preprint arXiv:2212.08751, 2022. 1, 6, 8", + "[27] Michael Niemeyer, Jonathan T Barron, Ben Mildenhall, Mehdi SM Sajjadi, Andreas Geiger, and Noha Radwan. Regnerf: Regularizing neural radiance fields for view synthesis from sparse inputs. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5480-5490, 2022. 2", + "[28] Simon Niklaus, Long Mai, Jimei Yang, and Feng Liu. 3d ken burns effect from a single image. ACM Transactions on Graphics (ToG), 38(6):1-15, 2019. 1, 2", + "[29] Kyle Olszewski, Sergey Tulyakov, Oliver Woodford, Hao Li, and Linjie Luo. Transformable bottleneck networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7648-7657, 2019. 2", + "[30] Xingang Pan, Bo Dai, Ziwei Liu, Chen Change Loy, and Ping Luo. Do 2d gans know 3d shape? unsupervised 3d shape reconstruction from 2d image gans. arXiv preprint arXiv:2011.00844, 2020. 3", + "[31] Eunbyung Park, Jimei Yang, Ersin Yumer, Duygu Ceylan, and Alexander C Berg. Transformation-grounded image generation network for novel 3d view synthesis. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3500-3509, 2017. 2", + "[32] Ben Poole, Ajay Jain, Jonathan T Barron, and Ben Mildenhall. Dreamfusion: Text-to-3d using 2d diffusion. arXiv preprint arXiv:2209.14988, 2022. 2, 3, 4, 5, 6, 7, 8", + "[33] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International conference on machine learning, pages 8748-8763. PMLR, 2021. 2, 3, 5, 8", + "[34] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022. 2" + ], + "bbox": [ + 78, + 90, + 468, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[35] René Ranftl, Alexey Bochkovskiy, and Vladlen Koltun. Vision transformers for dense prediction. ArXiv preprint, 2021. 5", + "[36] Konstantinos Rematas, Chuong H Nguyen, Tobias Ritschel, Mario Fritz, and Tinne Tuytelaars. Novel views of objects from a single image. IEEE transactions on pattern analysis and machine intelligence, 39(8):1576-1590, 2016. 2", + "[37] Chris Rockwell, David F. Fouhey, and Justin Johnson. Pixelsynth: Generating a 3d-consistent experience from a single image. In ICCV, 2021. 1", + "[38] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684-10695, 2022. 1, 2, 4, 7", + "[39] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022. 2, 4", + "[40] Jonathan Shade, Steven Gortler, Li-wei He, and Richard Szeliski. Layered depth images. In Proceedings of the 25th annual conference on Computer graphics and interactive techniques, pages 231–242, 1998. 3", + "[41] Meng-Li Shih, Shih-Yang Su, Johannes Kopf, and Jia-Bin Huang. 3d photography using context-aware layered depth inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8028-8038, 2020. 1, 3, 6, 8", + "[42] Vincent Sitzmann, Michael Zollhöfer, and Gordon Wetzstein. Scene representation networks: Continuous 3d-structure-aware neural scene representations. Advances in Neural Information Processing Systems, 32, 2019. 2", + "[43] Pratul P Srinivasan, Richard Tucker, Jonathan T Barron, Ravi Ramamoorthi, Ren Ng, and Noah Snively. Pushing the boundaries of view extrapolation with multiplane images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 175-184, 2019. 3", + "[44] Pratul P Srinivasan, Tongzhou Wang, Ashwin Sreelal, Ravi Ramamoorthi, and Ren Ng. Learning to synthesize a 4d rgbd light field from a single image. In Proceedings of the IEEE International Conference on Computer Vision, pages 2243-2251, 2017. 2", + "[45] Shao-Hua Sun, Minyoung Huh, Yuan-Hong Liao, Ning Zhang, and Joseph J Lim. Multi-view to novel view: Synthesizing novel views with self-learned confidence. In Proceedings of the European Conference on Computer Vision (ECCV), pages 155–171, 2018. 2", + "[46] Alex Trevithick and Bo Yang. Grf: Learning a general radiance field for 3d representation and rendering. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 15182-15192, 2021. 2", + "[47] Richard Tucker and Noah Snively. Single-view view synthesis with multiplane images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 551-560, 2020. 1, 3" + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "22828", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[48] Shubham Tulsiani, Richard Tucker, and Noah Snavely. Layer-structured 3d scene inference via view synthesis. In Proceedings of the European Conference on Computer Vision (ECCV), pages 302–317, 2018. 3", + "[49] Aaron Van Den Oord, Oriol Vinyals, et al. Neural discrete representation learning. Advances in neural information processing systems, 30, 2017. 4", + "[50] Haochen Wang, Xiaodan Du, Jiahao Li, Raymond A Yeh, and Greg Shakhnarovich. Score jacobian chaining: Lifting pretrained 2d diffusion models for 3d generation. arXiv preprint arXiv:2212.00774, 2022. 3", + "[51] Tengfei Wang, Bo Zhang, Ting Zhang, Shuyang Gu, Jianmin Bao, Tadas Baltrusaitis, Jingjing Shen, Dong Chen, Fang Wen, Qifeng Chen, et al. Rodin: A generative model for sculpting 3d digital avatars using diffusion. CVPR, 2023. 1", + "[52] Tengfei Wang, Ting Zhang, Bo Zhang, Hao Ouyang, Dong Chen, Qifeng Chen, and Fang Wen. Pretraining is all you need for image-to-image translation. In arXiv, 2022. 2", + "[53] Daniel Watson, William Chan, Ricardo Martin-Brualla, Jonathan Ho, Andrea Tagliasacchi, and Mohammad Norouzi. Novel view synthesis with diffusion models. arXiv preprint arXiv:2210.04628, 2022. 2", + "[54] Olivia Wiles, Georgia Gkioxari, Richard Szeliski, and Justin Johnson. Synsin: End-to-end view synthesis from a single image. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7467-7477, 2020. 1, 3", + "[55] Jiaxin Xie, Hao Ouyang, Jingtan Piao, Chenyang Lei, and Qifeng Chen. High-fidelity 3d gan inversion by pseudomulti-view optimization. CVPR, 2023. 1, 6", + "[56] Dejia Xu, Yifan Jiang, Peihao Wang, Zhiwen Fan, Humphrey Shi, and Zhangyang Wang. Sinnerf: Training neural radiance fields on complex scenes from a single image. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXII, pages 736-753. Springer, 2022. 1, 6, 7", + "[57] Dejia Xu, Yifan Jiang, Peihao Wang, Zhiwen Fan, Yi Wang, and Zhangyang Wang. Neurallift-360: Lifting an in-the-wild 2d photo to a 3d object with $360^{\\circ}$ views. 2022. 3", + "[58] Lior Yariv, Yoni Kasten, Dror Moran, Meirav Galun, Matan Atzmon, Basri Ronen, and Yaron Lipman. Multiview neural surface reconstruction by disentangling geometry and appearance. Advances in Neural Information Processing Systems, 33:2492-2502, 2020. 4", + "[59] Alex Yu, Vickie Ye, Matthew Tancik, and Angjoo Kanazawa. pixelnerf: Neural radiance fields from one or few images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4578-4587, 2021. 1, 2", + "[60] Jiahui Yu, Zhe Lin, Jamei Yang, Xiaohui Shen, Xin Lu, and Thomas S Huang. Free-form image inpainting with gated convolution. In Proceedings of the IEEE/CVF international conference on computer vision, pages 4471-4480, 2019. 6", + "[61] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 586-595, 2018. 8" + ], + "bbox": [ + 78, + 90, + 468, + 898 + ], + "page_idx": 10 + }, + { + "type": "ref_text", + "text": "[62] Tinghui Zhou, Shubham Tulsiani, Weilun Sun, Jitendra Malik, and Alexei A Efros. View synthesis by appearance flow. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part IV 14, pages 286-301. Springer, 2016. 2", + "bbox": [ + 501, + 92, + 890, + 161 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "22829", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/3c32b216-e73e-471f-8cad-0ce51b8a9a7c_model.json b/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/3c32b216-e73e-471f-8cad-0ce51b8a9a7c_model.json new file mode 100644 index 0000000000000000000000000000000000000000..8bb07fbe5a99b4e54bb266a6c1ca4a4963b17368 --- /dev/null +++ b/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/3c32b216-e73e-471f-8cad-0ce51b8a9a7c_model.json @@ -0,0 +1,3005 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.153, + 0.9, + 0.177 + ], + "angle": 0, + "content": "Make-It-3D: High-Fidelity 3D Creation from A Single Image with Diffusion Prior" + }, + { + "type": "text", + "bbox": [ + 0.235, + 0.203, + 0.735, + 0.223 + ], + "angle": 0, + "content": "Junshu Tang\\(^{1\\dagger}\\) Tengfei Wang\\(^{2\\dagger}\\) Bo Zhang\\(^{3‡}\\) Ting Zhang\\(^{3}\\)" + }, + { + "type": "text", + "bbox": [ + 0.334, + 0.224, + 0.658, + 0.241 + ], + "angle": 0, + "content": "Ran Yi\\(^{1}\\) Lizhuang Ma\\(^{1\\ddagger}\\) Dong Chen\\(^{3}\\)" + }, + { + "type": "text", + "bbox": [ + 0.221, + 0.242, + 0.75, + 0.261 + ], + "angle": 0, + "content": "\\(^{1}\\)Shanghai Jiao Tong University \\(^{2}\\)HKUST \\(^{3}\\)Microsoft Research" + }, + { + "type": "text", + "bbox": [ + 0.312, + 0.264, + 0.658, + 0.281 + ], + "angle": 0, + "content": "https://make-it-3d.github.io/" + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.288, + 0.191, + 0.453 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.104, + 0.455, + 0.168, + 0.467 + ], + "angle": 0, + "content": "Reference" + }, + { + "type": "image", + "bbox": [ + 0.203, + 0.293, + 0.275, + 0.373 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.191, + 0.379, + 0.294, + 0.453 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.223, + 0.455, + 0.272, + 0.467 + ], + "angle": 0, + "content": "Normal" + }, + { + "type": "image", + "bbox": [ + 0.309, + 0.293, + 0.378, + 0.373 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.295, + 0.38, + 0.399, + 0.454 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.361, + 0.455, + 0.44, + 0.467 + ], + "angle": 0, + "content": "Novel Views" + }, + { + "type": "image", + "bbox": [ + 0.411, + 0.293, + 0.477, + 0.373 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.4, + 0.381, + 0.501, + 0.454 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.499, + 0.289, + 0.608, + 0.453 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.525, + 0.455, + 0.589, + 0.467 + ], + "angle": 0, + "content": "Reference" + }, + { + "type": "image", + "bbox": [ + 0.624, + 0.289, + 0.681, + 0.373 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.618, + 0.373, + 0.699, + 0.453 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.629, + 0.455, + 0.678, + 0.467 + ], + "angle": 0, + "content": "Normal" + }, + { + "type": "image", + "bbox": [ + 0.707, + 0.29, + 0.761, + 0.373 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.703, + 0.373, + 0.783, + 0.453 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.747, + 0.455, + 0.825, + 0.467 + ], + "angle": 0, + "content": "Novel Views" + }, + { + "type": "image", + "bbox": [ + 0.794, + 0.289, + 0.844, + 0.373 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.785, + 0.375, + 0.887, + 0.453 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.473, + 0.892, + 0.504 + ], + "angle": 0, + "content": "Figure 1: Make-It-3D can create high-fidelity 3D content from only a single image. We show the normal map and novel-view renderings of created 3D content, showcasing fine geometry and faithful textures with stunning quality at novel views." + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.511, + 0.314, + 0.527 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.533, + 0.473, + 0.851 + ], + "angle": 0, + "content": "In this work, we investigate the problem of creating high-fidelity 3D content from only a single image. This is inherently challenging: it essentially involves estimating the underlying 3D geometry while simultaneously hallucinating unseen textures. To address this challenge, we leverage prior knowledge from a well-trained 2D diffusion model to act as 3D-aware supervision for 3D creation. Our approach, Make-It-3D, employs a two-stage optimization pipeline: the first stage optimizes a neural radiance field by incorporating constraints from the reference image at the frontal view and diffusion prior at novel views; the second stage transforms the coarse model into textured point clouds and further elevates the realism with diffusion prior while leveraging the high-quality textures from the reference image. Extensive experiments demonstrate that our method outperforms prior works by a large margin, resulting in faithful reconstructions and impressive visual quality. Our method presents the first attempt to achieve high-quality 3D creation from a single image for general objects and enables various applications such as text-to-3D creation and texture editing." + }, + { + "type": "title", + "bbox": [ + 0.502, + 0.511, + 0.632, + 0.527 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.538, + 0.892, + 0.749 + ], + "angle": 0, + "content": "Given a single image as in Figure 1, how would the object portrayed in the image look like from a different perspective? Humans possess an innate ability to effortlessly imagine 3D geometry and hallucinate the appearance of novel views with a glance at the picture based on their prior knowledge about the world. In this work, we aim to achieve a similar goal: creating high-fidelity 3D content from a real or artificially generated single image. This will open up new avenues for artistic expression and creativity, such as bringing 3D effects to the fantasy images given by the cutting-edge 2D generative models like Stable Diffusion [38]. By offering a more accessible and automated way to create visually stunning 3D content, we hope to engage a broader audience with the world of 3D modeling with ease." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.893, + 0.902 + ], + "angle": 0, + "content": "The creation of 3D objects from a single image presents a significant challenge due to the limited information that can be inferred from a single viewpoint. One categories of works aim to produce 3D photo effect [28, 41, 11, 47] in the manner of image-based rendering or single-view 3D reconstruction with neural rendering [54, 56, 37]. However, these methods often struggle with reconstructing fine geometry and fall short of rendering in large views. Another line of research [26, 51, 59, 55] projects the input image into the latent space of the pretrained 3D-aware generative networks." + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.875, + 0.409, + 0.888 + ], + "angle": 0, + "content": "\\(\\dagger\\)Work is done during the internship at Microsoft Research." + }, + { + "type": "page_footnote", + "bbox": [ + 0.098, + 0.888, + 0.227, + 0.9 + ], + "angle": 0, + "content": "\\(\\ddagger\\) Corresponding authors." + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.875, + 0.409, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.925, + 0.52, + 0.937 + ], + "angle": 0, + "content": "22819" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.212 + ], + "angle": 0, + "content": "Despite their impressive performance, the existing 3D generative networks mainly model objects from a specific class and are therefore incapable of handling general 3D objects. In our case, we aim for general 3D creation from an arbitrary image, yet constructing a sufficiently large and diverse dataset for estimating the novel views or building a powerful 3D foundation model for general objects remains insurmountable." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.215, + 0.473, + 0.398 + ], + "angle": 0, + "content": "Unlike the scarcity of 3D models, images are much more readily available, and recent advancements in diffusion models have sparked a revolution in 2D image generation [34, 39, 38, 52, 4]. Interestingly, we observed that well-trained image diffusion models can generate images under various views, which implies that they have already incorporated 3D knowledge. This has motivated us to explore the possibility of cultivating prior knowledge in a 2D diffusion model to reconstruct 3D objects. With diffusion prior, we propose Make-It-3D, a two-stage 3D content creation method that can generate a high-fidelity 3D object with superior quality from only one image." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.4, + 0.473, + 0.657 + ], + "angle": 0, + "content": "In the first stage, we leverage diffusion prior to optimize a neural radiance field (NeRF) [23] by applying score distillation sampling (SDS) [32], and constrain this optimization with reference-view supervision. Different from prior text-to-3D works [32, 18, 22], we focus on image-based 3D creation so that we need to prioritize the faithfulness to the reference image. However, we observed that while 3D models generated with SDS match text prompts well, they often fail to align faithfully with reference images since textual descriptions do not capture all object details. To address this issue, we go beyond SDS by simultaneously maximizing the image-level similarity between the reference and the novel view rendering denoised by a diffusion model. Also, as images inherently capture more geometry-related information than textual descriptions, we can thus incorporate the depth of the reference image as an extra geometry prior to alleviate the shape ambiguity of NeRF optimization." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.66, + 0.473, + 0.903 + ], + "angle": 0, + "content": "While the first stage generates a coarse model with plausible geometry, its appearance often deviates from the quality of the reference, exhibiting over-smooth textures and saturated colors [32]. This has limited its overall realism, and it is imperative to further bridge the gap between coarse model and reference image. As texture is more critical than geometry for human perception in the context of high-quality rendering, we choose to prioritize texture enhancement in the second stage, while inheriting the geometry from the first stage. We refine the model by leveraging the availability of ground-truth textures for regions that are observable in the reference image. To achieve this, we export the coarse NeRF model to textured point clouds and project reference textures onto their corresponding areas in the point clouds. We then utilize diffusion prior to enhance the texture of the remaining points by jointly optimizing" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.122 + ], + "angle": 0, + "content": "the point feature and a point cloud renderer, resulting in a clearly improved texture of the generated 3D model." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.122, + 0.894, + 0.287 + ], + "angle": 0, + "content": "With diffusion prior as multi-view supervision, our approach can be applied to general objects without being limited to specific categories. To evaluate the method, we create a benchmark consisting of 400 images including both real images and generated images from 2D diffusion. We evaluate the proposed method on public DTU dataset [1] and our benchmark, and extensive experiments show a clear improvement over previous works. Furthermore, our method enables a range of applications beyond image-to-3D creation such as texture editing and high-quality text-to-3D creation. Our main contributions are summarized as:" + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.288, + 0.892, + 0.363 + ], + "angle": 0, + "content": "- We propose Make-It-3D, a framework to create a high-fidelity 3D object from a single image, using a 2D diffusion model as 3D-aware prior. It does not require multi-view images for training and can be applied to any input image, whether it is real or generated." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.364, + 0.892, + 0.438 + ], + "angle": 0, + "content": "- With a two-stage creation scheme, Make-It-3D represents the first work to achieve high-fidelity 3D creation for general objects. The resulting 3D models exhibit detailed geometry and realistic textures that accurately conform to the reference images." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.44, + 0.892, + 0.484 + ], + "angle": 0, + "content": "- Beyond image-to-3D creation, our method enables multiple applications such as high-quality text-to-3D creation and texture editing." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.288, + 0.892, + 0.484 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.498, + 0.642, + 0.514 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.524, + 0.892, + 0.81 + ], + "angle": 0, + "content": "Novel view synthesis from a few images. Early attempts [14, 6, 45, 31] usually require dense observations of a scene from uniformly sampled poses. Recent emergence of implicit representations [42, 23] significantly advances the synthesis quality of novel views, whereas they tend to find a degenerate solution when given only very few input views. To enable novel view from sparse input views, a growing body of works [20, 46, 27] hence turn to extra prior knowledge as additional regularizations. PixelNeRF [59] predicts a continuous neural representation conditioned on the input images rather than only leveraging input views for supervision. DietNeRF [10] penalizes a semantic consistency loss by minimizing distance between CLIP [33] features of different views. With recent rapid progress of diffusion models, 3DiM [53] introduces a pose-conditional diffusion model that generates a novel view conditioned on a source view and a target pose. RenderDiffusion [3] presents a diffusion model for 3D generation that incorporates a triplane rendering mode into the denoiser." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.894, + 0.902 + ], + "angle": 0, + "content": "Single-image 3D photography. Synthesizing novel views from a single image is quite challenging as it is a highly ill-posed problem, requiring precise geometry estimation and disocclusion of both geometry and texture. Increasing effort has been dedicated to this problem [62, 7, 19, 29, 31, 36, 28, 44], many of which can only handle specific types. Among" + }, + { + "type": "footer", + "bbox": [ + 0.48, + 0.925, + 0.521, + 0.937 + ], + "angle": 0, + "content": "22820" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.124, + 0.096, + 0.226, + 0.109 + ], + "angle": 0, + "content": "1. Coarse Stage" + }, + { + "type": "image", + "bbox": [ + 0.119, + 0.112, + 0.262, + 0.221 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.158, + 0.222, + 0.223, + 0.233 + ], + "angle": 0, + "content": "Reference" + }, + { + "type": "image", + "bbox": [ + 0.291, + 0.107, + 0.441, + 0.215 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.298, + 0.216, + 0.442, + 0.228 + ], + "angle": 0, + "content": "Neural Radiance Field" + }, + { + "type": "image", + "bbox": [ + 0.455, + 0.144, + 0.484, + 0.159 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.447, + 0.162, + 0.489, + 0.171 + ], + "angle": 0, + "content": "Reference" + }, + { + "type": "image_caption", + "bbox": [ + 0.458, + 0.171, + 0.48, + 0.177 + ], + "angle": 0, + "content": "view" + }, + { + "type": "image", + "bbox": [ + 0.45, + 0.19, + 0.482, + 0.208 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.455, + 0.212, + 0.482, + 0.22 + ], + "angle": 0, + "content": "Novel" + }, + { + "type": "image_caption", + "bbox": [ + 0.456, + 0.221, + 0.482, + 0.229 + ], + "angle": 0, + "content": "views" + }, + { + "type": "image", + "bbox": [ + 0.49, + 0.101, + 0.553, + 0.16 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.493, + 0.169, + 0.56, + 0.233 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.56, + 0.102, + 0.622, + 0.16 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.565, + 0.169, + 0.63, + 0.234 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.623, + 0.118, + 0.692, + 0.131 + ], + "angle": 0, + "content": "\\(\\mathcal{L}_{ref}, \\mathcal{L}_{depth}\\)" + }, + { + "type": "image", + "bbox": [ + 0.634, + 0.133, + 0.676, + 0.146 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.698, + 0.098, + 0.781, + 0.161 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.719, + 0.163, + 0.762, + 0.171 + ], + "angle": 0, + "content": "Estimated" + }, + { + "type": "image_caption", + "bbox": [ + 0.719, + 0.172, + 0.753, + 0.18 + ], + "angle": 0, + "content": "Depth" + }, + { + "type": "image", + "bbox": [ + 0.789, + 0.104, + 0.859, + 0.163 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.798, + 0.164, + 0.836, + 0.171 + ], + "angle": 0, + "content": "Masked" + }, + { + "type": "image_caption", + "bbox": [ + 0.795, + 0.172, + 0.838, + 0.18 + ], + "angle": 0, + "content": "Reference" + }, + { + "type": "image_caption", + "bbox": [ + 0.121, + 0.292, + 0.221, + 0.304 + ], + "angle": 0, + "content": "2. Refine Stage" + }, + { + "type": "image", + "bbox": [ + 0.143, + 0.306, + 0.226, + 0.37 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.144, + 0.372, + 0.228, + 0.435 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.219, + 0.256, + 0.288, + 0.276 + ], + "angle": 0, + "content": "Image Caption Model" + }, + { + "type": "image_caption", + "bbox": [ + 0.329, + 0.253, + 0.474, + 0.278 + ], + "angle": 0, + "content": "A brown teddy bear sitting on a ground." + }, + { + "type": "image_caption", + "bbox": [ + 0.378, + 0.297, + 0.441, + 0.307 + ], + "angle": 0, + "content": "Invisible Points" + }, + { + "type": "image", + "bbox": [ + 0.326, + 0.311, + 0.438, + 0.416 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.452, + 0.312, + 0.522, + 0.32 + ], + "angle": 0, + "content": "#" + }, + { + "type": "image_caption", + "bbox": [ + 0.452, + 0.321, + 0.522, + 0.329 + ], + "angle": 0, + "content": "#" + }, + { + "type": "image_caption", + "bbox": [ + 0.455, + 0.331, + 0.522, + 0.339 + ], + "angle": 0, + "content": "#" + }, + { + "type": "image", + "bbox": [ + 0.455, + 0.34, + 0.468, + 0.347 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.455, + 0.348, + 0.47, + 0.357 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.455, + 0.36, + 0.47, + 0.367 + ], + "angle": 0, + "content": "XX" + }, + { + "type": "image_caption", + "bbox": [ + 0.475, + 0.36, + 0.523, + 0.368 + ], + "angle": 0, + "content": "Descriptors" + }, + { + "type": "image_caption", + "bbox": [ + 0.307, + 0.418, + 0.452, + 0.43 + ], + "angle": 0, + "content": "Textured Point Clouds" + }, + { + "type": "image_caption", + "bbox": [ + 0.544, + 0.304, + 0.562, + 0.427 + ], + "angle": 270, + "content": "Z-buffer & Rasterization" + }, + { + "type": "image", + "bbox": [ + 0.576, + 0.304, + 0.706, + 0.434 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.612, + 0.433, + 0.692, + 0.44 + ], + "angle": 0, + "content": "Deferred Renderer" + }, + { + "type": "image", + "bbox": [ + 0.71, + 0.296, + 0.851, + 0.427 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.724, + 0.427, + 0.838, + 0.439 + ], + "angle": 0, + "content": "Enhanced Output" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.45, + 0.892, + 0.511 + ], + "angle": 0, + "content": "Figure 2: Overview architecture. We propose a two-stage framework for creating a high-quality 3D model from a reference image with diffusion prior (Sec. 3.1). At the coarse stage, we optimize a NeRF for reconstructing the geometry of the reference image (Sec. 3.2). We further build textured point clouds from NeRF and the reference image, and jointly optimize the texture of invisible points and a learnable deferred renderer to generate realistic and view-consistent textures (Sec. 3.3)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.527, + 0.47, + 0.679 + ], + "angle": 0, + "content": "them, a number of methods rely on layered representations such as layered depth images [40, 48, 41] and multi-plane images (MPIs) [43, 47, 17, 8]. For example, [47] predicts MPIs for view synthesis from single image without requiring ground truth 3D. [41] generates a 3D photo from a given RGB-D input through layered depth image with inpainted color and depth. Yet such a solution is limited by the number of planes and sensitive to discontinuities. Subsequent efforts generalize MPIs to continuous 3D representations such as NeRF [15] and latent 3D point cloud [54]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.689, + 0.471, + 0.901 + ], + "angle": 0, + "content": "Lift 2D pretrained model to 3D. With the emergence of recent advances in modeling natural image manifold, how to exploit such powerful 2D pretrained model to recover 3D object structure has received considerable research interest. [30] attempts to reconstruct the 3D shape using pretrained 2D GANs. Subsequently, some works [9, 13, 24] explore zero-shot text-guided 3D content creation utilizing the guidance from CLIP [33]. Recent efforts such as DreamFusion [32], Magic3D [18] and Score Jacobian Chaining [50] explore text-to-3D generation by exploiting a score distillation sampling (SDS) loss derived from a 2D text-to-image diffusion model instead, showing impressive results. LatentNeRF [22] proposes to use a shape prior to guide and assist the 3D generation directly in the latent space" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.527, + 0.892, + 0.634 + ], + "angle": 0, + "content": "of the diffusion model. Prior works NeuralLift-360 [57] and NeRDi [5] also leverage the generative prior for 3D reconstruction from a single view. Yet the reconstructed 3D model has limited quality and is poorly aligned with the input image. In contrast, we propose a two-stage 3D synthesis framework with a relaxed SDS loss, yielding high-quality 3D representation faithful to the given input image." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.648, + 0.591, + 0.664 + ], + "angle": 0, + "content": "3. Method" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.675, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Generating novel views for general scenes or objects from only a single image is inherently challenging due to the difficulty of inferring both geometry and missing texture. We therefore tackle this challenge by cultivating the dark knowledge of pretrained 2D diffusion models. Specifically, given an input image \\( \\pmb{x} \\), we first hallucinate its underlying 3D representation, neural radiance field (NeRF), whose rendering appears as a plausible sample to a pretrained denoising diffusion model, and we constrain this optimization process with the texture and depth supervision at the reference view. To further improve the rendering realism, we keep the learned geometry and enhance the textures with the reference image. As such, in the second stage, we lift the input image to textured point clouds and focus on refining the color of the points occluded in the reference view." + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.518, + 0.937 + ], + "angle": 0, + "content": "22821" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.198 + ], + "angle": 0, + "content": "We leverage prior knowledge of the text-to-image generative model and the text-image contrastive model for both stages. In this way, we achieve a faithful 3D representation of the input image with restored high-fidelity texture and geometry. The proposed two-stage 3D learning framework is illustrated in Figure 2. We will subsequently brief the preliminaries and then detail our method." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.206, + 0.22, + 0.221 + ], + "angle": 0, + "content": "3.1. Preliminaries" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.23, + 0.47, + 0.38 + ], + "angle": 0, + "content": "Recent findings show that pretrained 2D generative models offer rich 3D geometry knowledge for their 2D generation samples. Notably, DreamFusion [32] uses a text-to-image diffusion model to guide the optimization of the 3D representation. Let \\(\\mathcal{G}_{\\theta}(\\beta)\\) be the rendered image at the given viewpoint \\(\\beta\\), where \\(\\mathcal{G}\\) is the differentiable rendering function for the 3D representation parameterized by \\(\\theta\\) and is amenable to choice. DreamFusion optimizes the neural radiance field such that its multi-view renderings look like high-quality samples from a frozen diffusion model." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.381, + 0.473, + 0.593 + ], + "angle": 0, + "content": "Specifically, a diffusion model \\(\\epsilon_{\\phi}\\) introduces a random amount of noise \\(\\epsilon\\) to the rendered image \\(\\pmb{x}_0 \\coloneqq \\mathcal{G}_{\\theta}(\\beta)\\) at different timestep \\(t\\), i.e., \\(\\pmb{x}_t = \\alpha_t \\pmb{x}_0 + \\sigma_t \\pmb{\\epsilon}\\), where \\(\\epsilon \\sim \\mathcal{N}(\\mathbf{0}, \\mathbf{I})\\); \\(\\alpha_t\\) and \\(\\sigma_t\\) define a noise schedule whose log signal-to-noise ratio \\(\\lambda_t = \\log[\\alpha_t^2 / \\sigma_t^2]\\) linearly decreases with the timestep \\(t\\). A pretrained text-conditioned diffusion model is trained to reverse this noising process given the text embedding \\(\\pmb{y}\\). To optimize the 3D representation parameters to render images as close as good generation samples, a score distillation sampling (SDS) loss \\(\\mathcal{L}_{\\mathrm{SDS}}\\) is introduced to push rendered images toward higher density region conditioned on the text embedding. Specifically, \\(\\mathcal{L}_{\\mathrm{SDS}}\\) computes the difference of predicted noise and the added noise as per-pixel gradient which is used to update the scene parameters, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.087, + 0.601, + 0.47, + 0.637 + ], + "angle": 0, + "content": "\\[\n\\nabla_ {\\theta} \\mathcal {L} _ {\\mathrm {S D S}} (\\phi , \\mathcal {G} _ {\\theta}) = \\mathbb {E} _ {t, \\epsilon} \\left[ w (t) \\left(\\epsilon_ {\\phi} \\left(\\boldsymbol {x} _ {t}; \\boldsymbol {y}, t\\right) - \\epsilon\\right) \\frac {\\partial \\boldsymbol {x}}{\\partial \\theta} \\right], \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.644, + 0.47, + 0.795 + ], + "angle": 0, + "content": "where \\( w(t) \\) is a weight function of different noise levels. It can be proved that this loss essentially measures the similarity between the image and the text prompt. The diffusion model acts as a critic and the gradient of \\( \\mathcal{L}_{\\mathrm{SDS}} \\) will not be back-propagated through the diffusion network, resulting in efficient computation. As training proceeds, the NeRF parameters are updated during which the 3D object gradually reveals its texture and geometry. In practice, it is found that using a diffusion model with a strong classifier-free guidance leads to higher-quality 3D samples." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.796, + 0.471, + 0.902 + ], + "angle": 0, + "content": "While DreamFusion uses the Imagen [39] to reverse the noising process at the pixel level, we use the publicly available Stable Diffusion [38] that models the latent space of the VQ-VAE [49] with an encoder \\(\\mathcal{E}\\) and a decoder \\(\\mathcal{D}\\). Hence, the used diffusion model digests the latent \\(z_0 \\coloneqq \\mathcal{E}(\\mathcal{G}_{\\theta}(\\beta))\\) and the reconstructed latent \\(\\hat{z}_0\\) can be mapped to image space through \\(\\hat{\\boldsymbol{x}} = \\mathcal{D}(\\hat{z}_0)\\)." + }, + { + "type": "image", + "bbox": [ + 0.501, + 0.089, + 0.892, + 0.186 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.19, + 0.894, + 0.251 + ], + "angle": 0, + "content": "Figure 3: Analysis on the coarse stage. Baseline is a naive solution using only \\(\\mathcal{L}_{\\mathrm{SDS}}\\) and \\(\\mathcal{L}_{\\mathrm{ref}}\\), and it does not match the reference well. With \\(\\mathcal{L}_{\\mathrm{CLIP-D}}\\), the result aligns better with the reference. The depth prior further improves faithfulness." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.275, + 0.885, + 0.291 + ], + "angle": 0, + "content": "3.2. Coarse Stage: Single-view 3D Reconstruction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.298, + 0.892, + 0.493 + ], + "angle": 0, + "content": "As the first stage, we reconstruct a coarse NeRF from the single reference image \\( \\pmb{x} \\) with the diffusion prior constraining the novel views. Our optimization is expected to meet the following requirements simultaneously: 1) the optimized 3D representation should closely resemble the rendering appearance of the input observation \\( \\pmb{x} \\) at the reference view; 2) the novel view renderings should demonstrate consistent semantics with the input and appear as plausible as possible; 3) the generated 3D model should exhibit compelling geometry. In view of these, we randomly sample the camera poses around the reference view and enforce constraints upon the rendered images \\( \\mathcal{G}_{\\theta} \\) for both the reference view and unseen views." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.495, + 0.892, + 0.555 + ], + "angle": 0, + "content": "Reference view per-pixel loss. To encourage consistent appearance with the input image, we penalize the pixel-wise difference between the rendering and the input image at the reference view \\(\\beta_{\\mathrm{ref}}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.596, + 0.564, + 0.892, + 0.581 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {r e f}} = \\left\\| \\boldsymbol {x} \\odot \\boldsymbol {m} - \\mathcal {G} _ {\\theta} \\left(\\beta_ {\\text {r e f}}\\right) \\right\\| _ {1}. \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.59, + 0.892, + 0.636 + ], + "angle": 0, + "content": "Here we apply the foreground matting mask \\( \\pmb{m} \\) to segment out the foreground as we empirically find that this eases the geometry reconstruction, which conforms to [58]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.636, + 0.892, + 0.817 + ], + "angle": 0, + "content": "Diffusion prior. Optimizing with the aforementioned losses can be unstable and may lead to implausible results, due to the ill-posed nature of the problem. In order to encourage semantically plausible results, additional constraints are needed on the novel view rendering. To tackle this challenge, we resort to the diffusion prior. Prior works on text-to-3D [32, 18] applied \\(\\mathcal{L}_{\\mathrm{SDS}}\\) to leverage text-conditioned diffusion models as 3D-aware prior. To utilize \\(\\mathcal{L}_{\\mathrm{SDS}}\\) in our case, we use an image captioning model [16], to generate a detailed text description \\(y\\) for the reference image. With the text prompt \\(y\\), we can perform the SDS on the latent space of Stable Diffusion," + }, + { + "type": "equation", + "bbox": [ + 0.508, + 0.825, + 0.892, + 0.871 + ], + "angle": 0, + "content": "\\[\n\\nabla_ {\\theta} \\mathcal {L} _ {\\mathrm {S D S}} (\\phi , \\mathcal {G} _ {\\theta}) = \\mathbb {E} _ {t, \\epsilon} \\left[ w (t) \\left(\\epsilon_ {\\phi} \\left(\\boldsymbol {z} _ {t}; \\boldsymbol {y}, t\\right) - \\epsilon\\right) \\frac {\\partial \\boldsymbol {z}}{\\partial \\boldsymbol {x}} \\frac {\\partial \\boldsymbol {x}}{\\partial \\theta} \\right], \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "where the noisy latent \\( \\mathbf{z}_t \\) is obtained from a novel view rendering \\( \\mathbf{x} \\) by Stable Diffusion encoder." + }, + { + "type": "footer", + "bbox": [ + 0.479, + 0.925, + 0.521, + 0.937 + ], + "angle": 0, + "content": "22822" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.089, + 0.156, + 0.214 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.166, + 0.089, + 0.226, + 0.214 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.238, + 0.108, + 0.301, + 0.213 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.305, + 0.089, + 0.386, + 0.213 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.393, + 0.107, + 0.468, + 0.212 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.092, + 0.22, + 0.454, + 0.236 + ], + "angle": 0, + "content": "Figure 4: \\(360^{\\circ}\\) object reconstruction from real images." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.259, + 0.47, + 0.381 + ], + "angle": 0, + "content": "However, as discussed before, \\(\\mathcal{L}_{\\mathrm{SDS}}\\) essentially measures the similarity between the image and the given text prompt. While \\(\\mathcal{L}_{\\mathrm{SDS}}\\) can generate 3D models that are faithful to the text prompt, they do not align perfectly with the reference image (see baseline in Figure 3), since text prompts cannot capture all object details. We go beyond this by a diffusion CLIP loss, denoted as \\(\\mathcal{L}_{\\mathrm{CLIP-D}}\\), that additionally enforces the generated model to match the reference image:" + }, + { + "type": "equation", + "bbox": [ + 0.093, + 0.388, + 0.47, + 0.406 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {C L I P - D}} (\\mathcal {X}, \\mathcal {G} _ {\\theta} (\\beta)) = - \\mathcal {E} _ {\\mathrm {C L I P}} (\\mathcal {X}) \\cdot \\mathcal {E} _ {\\mathrm {C L I P}} (\\hat {\\mathcal {X}} _ {0} (\\beta , t)), \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.412, + 0.469, + 0.532 + ], + "angle": 0, + "content": "where \\(\\mathcal{E}_{\\mathrm{CLIP}}(\\cdot)\\) is a CLIP image encoder [33]. Rather than directly measuring CLIP loss on the rendered images \\(\\mathcal{G}_{\\theta}(\\beta)\\), we encode the novel view rendering \\(\\mathcal{G}_{\\theta}(\\beta)\\) to noisy latent \\(z_{t}\\) and then denoise it to a clean image \\(\\tilde{\\mathcal{X}}_0(\\beta, t)\\) with 2D diffusion. By imposing the similarity loss on denoised images sampled from diffusion models, we encourage the rendering to align with the reference image, while resembling high-quality samples from a frozen diffusion." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.533, + 0.469, + 0.638 + ], + "angle": 0, + "content": "In detail, we do not optimize \\(\\mathcal{L}_{\\mathrm{CLIP - D}}\\) and \\(\\mathcal{L}_{\\mathrm{SDS}}\\) at the same time. We use \\(\\mathcal{L}_{\\mathrm{CLIP - D}}\\) at small timesteps and switch to \\(\\mathcal{L}_{\\mathrm{SDS}}\\) at large timesteps. More details and analysis are in the Supplement. Combining \\(\\mathcal{L}_{\\mathrm{SDS}}\\) and \\(\\mathcal{L}_{\\mathrm{CLIP - D}}\\), our diffusion prior ensures that the resulting 3D model appears visually appealing and plausible while also conforming to the given image (see Figure 3)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.639, + 0.47, + 0.866 + ], + "angle": 0, + "content": "Depth prior. Nonetheless, even if the rendered image appears meaningful to the diffusion model, there still exists shape ambiguity that brings about issues such as sunken faces, over-flat geometry [32] or depth ambiguity (see Figure 3). We mitigate these by leveraging depth prior learned from abundant external images and directly enforcing the supervision in 3D. To be specific, we utilize an off-the-shelf single-view depth estimator [35] to estimate the depth \\(d\\) for the input image. While the estimated depth may not accurately characterize the geometric detail, it suffices to ensure plausible geometry and resolve most of the ambiguity. To account for the inaccuracy and the scale mismatch in \\(d\\), akin to [5], we regularize the negative Pearson correlation between the estimated depth and the depth \\(d(\\beta_{\\mathrm{ref}})\\) modeled by NeRF at the reference viewpoint, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.168, + 0.871, + 0.469, + 0.906 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {d e p t h}} = - \\frac {\\operatorname {C o v} \\left(d \\left(\\beta_ {\\text {r e f}}\\right) , d\\right)}{\\operatorname {V a r} \\left(d \\left(\\beta_ {\\text {r e f}}\\right)\\right) \\operatorname {V a r} (d)}, \\tag {5}\n\\]" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.089, + 0.892, + 0.24 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.247, + 0.892, + 0.293 + ], + "angle": 0, + "content": "Figure 5: Illustration of textured point cloud building. We aim at building dense points and texturing visible points using reference image, and invisible points from NeRF." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.308, + 0.892, + 0.369 + ], + "angle": 0, + "content": "where \\(\\mathrm{Cov}(\\cdot)\\) denotes the covariance, \\(\\mathrm{Var}(\\cdot)\\) computes the standard deviation. With this regularization, the NeRF depth estimation is encouraged to be linearly correlated with the depth prior." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.369, + 0.892, + 0.475 + ], + "angle": 0, + "content": "Overall training. The overall loss can be formulated as a combination of \\(\\mathcal{L}_{\\mathrm{ref}}\\), \\(\\mathcal{L}_{\\mathrm{SDS}}\\), \\(\\mathcal{L}_{\\mathrm{CLIP-D}}\\) and \\(\\mathcal{L}_{\\mathrm{depth}}\\). To stabilize the optimization process, we adopt a progressive training strategy, where we start with a narrow range of views near the reference view and gradually expand the range during training. With progressive training, we can achieve a \\(360^{\\circ}\\) reconstruction of an object, as shown in Figure 4." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.485, + 0.871, + 0.501 + ], + "angle": 0, + "content": "3.3. Refine Stage: Neural Texture Enhancement" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.508, + 0.892, + 0.613 + ], + "angle": 0, + "content": "After the coarse stage, we obtained a 3D model with plausible geometry, but it often displays coarse textures that can bottleneck the overall quality in Figure 6. Further refinement is thus desired for high-fidelity 3D models. Given that humans are more discerning when it comes to texture quality than geometry, we prioritize texture enhancement while preserving the geometry of the coarse model." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.615, + 0.892, + 0.718 + ], + "angle": 0, + "content": "Our key insight for texture enhancement is that for a novel view, certain pixels can be observable in both the novel and reference views. Consequently, we can exploit this overlap to project the high-quality texture of the reference image onto the corresponding areas of the 3D representation. We then focus on enhancing the textures of regions that are occluded in the reference view." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.892, + 0.825 + ], + "angle": 0, + "content": "While NeRF is a suitable representation in the coarse stage as it can handle topological changes continuously, projecting the reference image onto it is challenging. We thus opt to export the neural radiance field to an explicit representation, specifically point clouds. Compared to the noisy mesh exported by marching cube, point clouds offer a cleaner and more straightforward projection." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Textured point cloud building. A naive attempt to build point clouds is to render multi-view RGBD images from NeRF and lift them to textured points in 3D space. However, we found this simple method leads to noisy point clouds due to the conflict among different views: a 3D point" + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.518, + 0.936 + ], + "angle": 0, + "content": "22823" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.088, + 0.172, + 0.239 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.177, + 0.089, + 0.24, + 0.238 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.249, + 0.089, + 0.315, + 0.239 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.318, + 0.089, + 0.39, + 0.239 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.393, + 0.089, + 0.466, + 0.239 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.244, + 0.47, + 0.304 + ], + "angle": 0, + "content": "Figure 6: Visualization of neural texture enhancement. We project the reference textures to the coarse model and enhance the remaining regions to high-frequency details consistent with the reference. Best viewed with zoom-in." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.324, + 0.469, + 0.37 + ], + "angle": 0, + "content": "may possess different RGB colors in NeRF rendering under different views [55]. We thus propose an iterative strategy to build clean point clouds from multi-view observations." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.371, + 0.469, + 0.416 + ], + "angle": 0, + "content": "As in Figure 5, we first build point clouds from the reference view \\(\\beta_{\\mathrm{ref}}\\) according to the rendered depth \\(\\mathcal{D}(\\beta_{\\mathrm{ref}})\\) and alpha mask \\(M(\\beta_{\\mathrm{ref}})\\) of NeRF," + }, + { + "type": "equation", + "bbox": [ + 0.13, + 0.43, + 0.469, + 0.448 + ], + "angle": 0, + "content": "\\[\nV \\left(\\beta_ {\\text {r e f}}\\right) = R _ {\\text {r e f}} K ^ {- 1} \\mathcal {P} \\left(\\mathcal {D} \\left(\\beta_ {\\text {r e f}}\\right) * M \\left(\\beta_ {\\text {r e f}}\\right)\\right), \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.462, + 0.47, + 0.658 + ], + "angle": 0, + "content": "where \\( R_{\\mathrm{ref}} \\) and \\( K \\) are the extrinsic and intrinsic matrices of the camera, and \\( \\mathcal{P} \\) denotes depth-to-point projection. These points are visible under the reference view and thus colorized with ground-truth textures. For the projection of the remaining views \\( \\beta_{i} \\), it is important to avoid introducing points that overlap with existing points but have conflicting colors. To this end, we project the existing points \\( V(\\beta_{\\mathrm{ref}}) \\) to the novel view \\( \\beta_{i} \\) to yield a mask indicating the presence of existing points. With this mask as guidance, we only lift those points \\( V(\\beta_{i}) \\) that have not been observed yet, as shown in Figure 5. These invisible points are then initialized with coarse textures from NeRF rendering \\( \\mathcal{G}(\\beta_{i}) \\) and integrated into the dense point clouds." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.66, + 0.471, + 0.901 + ], + "angle": 0, + "content": "Deferred point cloud rendering. So far, we have built a set of textured point clouds \\( V = \\{V(\\beta_{\\mathrm{ref}}), V(\\beta_1), \\dots, V(\\beta_N)\\} \\). Though \\( V(\\beta_{\\mathrm{ref}}) \\) already have high-fidelity textures projected from the reference image, the other points that are occluded in the reference view still suffer smooth textures from the coarse NeRF, as shown in Figure 6. To enhance the texture, we optimize the texture of the other points and constrain novel-view rendering with diffusion prior. Specifically, we optimize a 19-dimensional descriptor \\( F \\) for each point, whose first three dimensions are initialized with the initial RGB colors. To avoid noisy colors and bleeding artifacts [2], we adopt a multi-scale deferred rendering scheme. In particular, given a novel view \\( \\beta \\), we rasterize the point cloud \\( \\mathbf{V} \\) for \\( K \\) times to obtain \\( K \\) feature maps \\( I_i \\) with varying sizes of \\( [W/2^i, H/2^i] \\), where \\( i \\in [0, K) \\). These feature maps are then concatenated and rendered into an image \\( \\mathbf{I} \\)" + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.089, + 0.89, + 0.216 + ], + "angle": 0, + "content": "
ViewsLPIPS↓Contextual↓CLIP↑
DietNeRF [10]30.18315.3464.90%
SinNeRF [56]10.20594.2873.24%
DreamFusion+ [32]10.40752.1582.81%
Point-E [26]1-2.2371.31%
3D-Photo [41]103.4387.65%
Ours-coarse10.14271.7487.50%
Ours-enhanced10.09081.5995.65%
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.218, + 0.892, + 0.276 + ], + "angle": 0, + "content": "Table 1: Quantitative comparison on DTU. We compute LPIPS under the reference view, and other two metrics under novel views. LPIPS of Point-E is not reported due to the lack of a defined reference view." + }, + { + "type": "table", + "bbox": [ + 0.53, + 0.282, + 0.863, + 0.369 + ], + "angle": 0, + "content": "
LPIPS↓Contextual↓CLIP↑
DreamFusion+ [32]0.56493.0784.08%
Point-E [26]-5.3764.36%
Ours-coarse0.23541.9889.06%
Ours-enhanced0.07801.3395.12%
" + }, + { + "type": "table_caption", + "bbox": [ + 0.509, + 0.372, + 0.882, + 0.386 + ], + "angle": 0, + "content": "Table 2: Quantitative comparison on the test benchmark." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.403, + 0.866, + 0.418 + ], + "angle": 0, + "content": "using a U-Net renderer \\(\\mathcal{R}_{\\theta}\\) [2] that is jointly optimized:" + }, + { + "type": "equation", + "bbox": [ + 0.563, + 0.43, + 0.791, + 0.447 + ], + "angle": 0, + "content": "\\[\nI _ {i} (\\beta) = \\mathcal {S} (i, V, F, \\beta), i \\in [ 0, K),\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.565, + 0.442, + 0.891, + 0.466 + ], + "angle": 0, + "content": "\\[\n\\mathbf {I} (\\beta) = \\mathcal {R} _ {\\theta} \\left(I _ {0} (\\beta), I _ {1} (\\beta), \\dots , I _ {K - 1} (\\beta)\\right), \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.476, + 0.892, + 0.582 + ], + "angle": 0, + "content": "where \\( S \\) is a differentiable point rasterizer. The objective of the texture enhancement process is similar to that of the geometry creation discussed in Sec. 3.2, but we additionally include a regularization term that penalizes large differences between the optimized texture and the initial texture. With the texture enhancement process, fine-detailed texture is generated on the occluded points." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.596, + 0.633, + 0.613 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.621, + 0.716, + 0.636 + ], + "angle": 0, + "content": "4.1. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.644, + 0.892, + 0.765 + ], + "angle": 0, + "content": "NeRF rendering. We use the multi-scale hash encoding from Instant-NGP [25] to implement the NeRF representation in the coarse optimization stage, which enables neural rendering at a computational cost. Similar to Instant-NGP, we maintain an occupancy grid to enable efficient ray sampling by skipping empty space. Additionally, we adopt several shading augmentations on the rendered images, such as Lambertian and normal shading, akin to [32]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.766, + 0.892, + 0.856 + ], + "angle": 0, + "content": "Point cloud rendering. For deferred rendering, we use a 2D U-Net architecture with gated convolutions [60]. The dimension of the point descriptor is 19, where the first 3 dimensions are initialized RGB colors and the remaining dimensions are randomly initialized. We also set a learnable descriptor for the background." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Camera setting. Following the camera sampling method used in [32], we randomly sample novel views with a \\(75\\%\\) probability and sample the pre-defined reference view with" + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.519, + 0.936 + ], + "angle": 0, + "content": "22824" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.078, + 0.086, + 0.891, + 0.384 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.39, + 0.893, + 0.422 + ], + "angle": 0, + "content": "Figure 7: Qualitative comparison on the test benchmark with two diffusion-based 3D content creation models, Dreamfusion and Point-E. We show our results with high-fidelity geometry and texture. The results of Dreamfusion are from its website." + }, + { + "type": "image", + "bbox": [ + 0.078, + 0.435, + 0.891, + 0.576 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.581, + 0.893, + 0.612 + ], + "angle": 0, + "content": "Figure 8: Qualitative comparison of novel view synthesis on DTU with state of the arts. Our method generates sharper and more plausible details in both geometry and texture." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.628, + 0.47, + 0.658 + ], + "angle": 0, + "content": "a \\(25\\%\\) probability. We also randomly enlarge the FOV when rendering with NeRF, following [18]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.659, + 0.47, + 0.839 + ], + "angle": 0, + "content": "Score distillation sampling. We randomly sample \\( t \\) from 0.2 to 0.6, and set \\( w(t) \\) as a uniform weighting depending on the timestep. We also use classifier-free guidance with a guidance weight \\( \\omega : \\hat{\\epsilon}_{\\phi}(z_t; y, t) = (1 + \\omega)\\epsilon_{\\phi}(z_t; y, t) - \\omega \\epsilon_{\\phi}(z_t; t) \\). Our method aims to align the created 3D model with the input image, and we use a guidance weight \\( \\omega = 10 \\). Training speed. We use Adam [12] with a learning rate of 0.001 for both stages. The coarse stage is trained for 5,000 iterations at a rendering resolution of \\( 100 \\times 100 \\). The refine stage then takes another 5,000 iterations at a rendering resolution of \\( 800 \\times 800 \\). The entire training process takes approximately 2 hours on a single Tesla 32GB V100 GPU." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Test Benchmark. To the best of our knowledge, we are the first method focusing on high-fidelity 3D creation from an arbitrary image. So we build a test benchmark consisting of 400 images, comprising both real images and images gener-" + }, + { + "type": "table", + "bbox": [ + 0.511, + 0.626, + 0.882, + 0.659 + ], + "angle": 0, + "content": "
Preference RateGeometry QualityTexture QualityFidelity to Input
Ours/DreamFusion+88.2%/11.8%95.6%/4.4%96.5%/3.5%
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.661, + 0.892, + 0.692 + ], + "angle": 0, + "content": "Table 3: Preference rate of geometry quality, texture quality, and fidelity to the input image." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.713, + 0.892, + 0.79 + ], + "angle": 0, + "content": "ated by Stable Diffusion [38]. Each image in the benchmark is accompanied by a foreground alpha mask, an estimated depth map, and a text prompt. The text prompts for real images are obtained from an image caption model [16]. We will make this test benchmark publicly available." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.801, + 0.836, + 0.817 + ], + "angle": 0, + "content": "4.2. Comparisons with the State of the Arts" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Baselines. We compare our method with five representative baselines. 1) DietNeRF [10], a few-shot NeRF. We train it with three input views. 2) SinNeRF [56], a single-view NeRF method. 3) DreamFusion [32]. As it is originally conditioned on text prompts, we also modify it with image" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.925, + 0.519, + 0.937 + ], + "angle": 0, + "content": "22825" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.089, + 0.47, + 0.239 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.246, + 0.47, + 0.276 + ], + "angle": 0, + "content": "Figure 9: Make-It-3D enables high-fidelity 3D creation on real complex scenes." + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.277, + 0.468, + 0.464 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.47, + 0.469, + 0.501 + ], + "angle": 0, + "content": "Figure 10: Make-It-3D generates diverse and visually stunning 3D models given a text description." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.52, + 0.469, + 0.58 + ], + "angle": 0, + "content": "reconstruction loss at the reference view, referred as Dream-Fusion+ for fair comparison. 4) Point-E [26], point cloud generation conditioned on image. 5) 3D-Photo [41], depth-based image warping and inpainting method." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.582, + 0.47, + 0.807 + ], + "angle": 0, + "content": "Qualitative comparison. We first compare our method with 3D generation baselines, where DreamFusion and DreamFusion+ leverage 2D diffusion as 3D prior and PointE is a 3D diffusion model. As shown in Figure 7, their generated models fail to align faithfully with the reference image and suffer smooth textures. In contrast, our method produces high-fidelity 3D models with fine geometry and realistic textures. Figure 8 shows additional comparison on novel view synthesis. SinNeRF and DietNeRF encounter difficulties in reconstructing complex objects due to the lack of multi-view supervision. 3D-Photo fails to reconstruct underlying geometry and produces visible artifacts in large views. In comparison, our method achieves remarkably faithful geometry and visually pleasing textures under novel views." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.81, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Quantitative comparison. A compelling generated 3D model should closely resemble the input image at the reference view, and demonstrate consistent semantics with the reference under novel views. We evaluate these two aspects using the following metrics: 1) LPIPS [61], which assesses the reconstruction quality at the reference view, 2) context-" + }, + { + "type": "image", + "bbox": [ + 0.523, + 0.088, + 0.871, + 0.33 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.337, + 0.892, + 0.368 + ], + "angle": 0, + "content": "Figure 11: Make-It-3D achieves 3D-aware texture modification such as tattoo drawing and stylization." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.383, + 0.892, + 0.474 + ], + "angle": 0, + "content": "tual distance [21], which measures pixel-level similarity between novel-view rendering and the reference, and 3) CLIP score [33], which evaluates the semantic similarity between the novel view and the reference. As shown in Table 1 and Table 2, our approach substantially outperforms baselines in terms of both reference-view and novel-view quality." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.476, + 0.892, + 0.581 + ], + "angle": 0, + "content": "User study. In order to obtain the user's subjective evaluation of the plausibility of the results, we conduct a user study on 30 participants. In the study, we use 25 pairs of results generated by our method and Dreamfusion+, respectively. All results are presented side-by-side and in a random order to participants. Based on the ratings in Table 3, our method outperformed Dreamfusion+ in all aspects." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.6, + 0.63, + 0.617 + ], + "angle": 0, + "content": "5. Applications" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.626, + 0.892, + 0.702 + ], + "angle": 0, + "content": "Real scene modeling. As shown in Figure 9, Make-It-3D can successfully convert a single photo of a complex scene to a 3D model, such as buildings and landscapes. This empowers users to model a scene with ease, which could be difficult for some traditional 3D modeling techniques." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.703, + 0.892, + 0.824 + ], + "angle": 0, + "content": "High-quality text-to-3D generation with diversity. Prior arts [32, 18] often produce models with limited diversity and excessively smooth textures. To perform high-quality text-to-3D creation, we first convert the text prompt to a reference image using 2D diffusion, and proceed with our image-based 3D creation method. As shown in Figure 10, Make-It-3D is capable of producing diverse examples from a text prompt that exhibit stunning quality." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "3D-aware texture modification. Make-It-3D enables view-consistent texture editing by manipulating the reference image in the refine stage while freezing the geometry. Figure 11 shows that we can add a tattoo and apply stylization to the generated 3D model." + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.519, + 0.936 + ], + "angle": 0, + "content": "22826" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.091, + 0.205, + 0.106 + ], + "angle": 0, + "content": "6. Conclusions" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.116, + 0.473, + 0.268 + ], + "angle": 0, + "content": "We introduce Make-It-3D, a novel two-stage method for creating high-fidelity 3D content from one single image. Leveraging diffusion prior as 3D-aware supervision, the generated 3D models exhibit faithful geometry and realistic textures with the diffusion CLIP loss and textured point cloud enhancement. Make-It-3D is applicable to general objects, empowering versatile fascinating applications. We believe our method takes a big step in extending the success of 2D content creation to 3D, providing users with a fresh 3D creation experience." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.284, + 0.258, + 0.302 + ], + "angle": 0, + "content": "7. Acknowledgement" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.31, + 0.47, + 0.417 + ], + "angle": 0, + "content": "The research is supported by National Natural Science Foundation of China (61972157, 72192821), Shanghai Municipal Science and Technology Major Project (2021SHZDZX0102), Shanghai Science and Technology Commission (21511101200), Shanghai Sailing Program (22YF1420300, 23YF1410500) and Young Elite Scientists Sponsorship Program by CAST (2022QNRC001)." + }, + { + "type": "title", + "bbox": [ + 0.079, + 0.433, + 0.175, + 0.449 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.459, + 0.47, + 0.514 + ], + "angle": 0, + "content": "[1] Henrik Aanaes, Rasmus Ramsbøl Jensen, George Vogiatzis, Engin Tola, and Anders Bjorholm Dahl. Large-scale data for multiple-view stereopsis. International Journal of Computer Vision, pages 1-16, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.516, + 0.47, + 0.585 + ], + "angle": 0, + "content": "[2] Kara-Ali Aliev, Artem Sevastopolsky, Maria Kolos, Dmitry Ulyanov, and Victor Lempitsky. Neural point-based graphics. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XXII 16, pages 696-712. Springer, 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.588, + 0.47, + 0.655 + ], + "angle": 0, + "content": "[3] Titas Anciukevicius, Zexiang Xu, Matthew Fisher, Paul Henderson, Hakan Bilen, Niloy J Mitra, and Paul Guerrero. Renderdiffusion: Image diffusion for 3d reconstruction, inpainting and generation. arXiv preprint arXiv:2211.09869, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.659, + 0.469, + 0.728 + ], + "angle": 0, + "content": "[4] Yogesh Balaji, Seungjun Nah, Xun Huang, Arash Vahdat, Jiaming Song, Karsten Kreis, Miika Aittala, Timo Aila, Samuli Laine, Bryan Catanzaro, Tero Karras, and Ming-Yu Liu. ediff-i: Text-to-image diffusion models with an ensemble of expert denoisers. ArXiv, abs/2211.01324, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.73, + 0.469, + 0.799 + ], + "angle": 0, + "content": "[5] Congyue Deng, Chiyu Jiang, Charles R Qi, Xinchen Yan, Yin Zhou, Leonidas Guibas, Dragomir Anguelov, et al. Nerdi: Single-view nerf synthesis with language-guided diffusion as general image priors. arXiv preprint arXiv:2212.03267, 2022. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.802, + 0.469, + 0.857 + ], + "angle": 0, + "content": "[6] Steven J Gortler, Radek Grzesczuk, Richard Szeliski, and Michael F Cohen. The lumigraph. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, pages 43-54, 1996. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.86, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[7] Tewodros Habtegebrial, Kiran Varanasi, Christian Bailer, and Didier Stricker. Fast view synthesis with deep stereo vision. arXiv preprint arXiv:1804.09690, 2018. 2" + }, + { + "type": "list", + "bbox": [ + 0.087, + 0.459, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.093, + 0.892, + 0.148 + ], + "angle": 0, + "content": "[8] Yuxuan Han, Ruicheng Wang, and Jiaolong Yang. Single-view synthesis in the wild with learned adaptive multiplane images. In ACM SIGGRAPH 2022 Conference Proceedings, pages 1-8, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.511, + 0.151, + 0.894, + 0.218 + ], + "angle": 0, + "content": "[9] Ajay Jain, Ben Mildenhall, Jonathan T Barron, Pieter Abbeel, and Ben Poole. Zero-shot text-guided object generation with dream fields. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 867-876, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.221, + 0.894, + 0.276 + ], + "angle": 0, + "content": "[10] Ajay Jain, Matthew Tancik, and Pieter Abbeel. Putting nerf on a diet: Semantically consistent few-shot view synthesis. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 5885-5894, 2021. 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.278, + 0.892, + 0.373 + ], + "angle": 0, + "content": "[11] Varun Jampani, Huiwen Chang, Kyle Sargent, Abhishek Kar, Richard Tucker, Michael Krainin, Dominik Kaeser, William T Freeman, David Salesin, Brian Curless, et al. Slide: Single image 3d photography with soft layering and depth-aware inpainting. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 12518-12527, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.376, + 0.892, + 0.415 + ], + "angle": 0, + "content": "[12] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014.7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.419, + 0.892, + 0.459 + ], + "angle": 0, + "content": "[13] Han-Hung Lee and Angel X Chang. Understanding pure clip guidance for voxel grid nerf models. arXiv preprint arXiv:2209.15172, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.462, + 0.892, + 0.503 + ], + "angle": 0, + "content": "[14] Marc Levoy and Pat Hanrahan. Light field rendering. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, pages 31-42, 1996. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.505, + 0.894, + 0.573 + ], + "angle": 0, + "content": "[15] Jiaxin Li, Zijian Feng, Qi She, Henghui Ding, Changhu Wang, and Gim Hee Lee. Mine: Towards continuous depth spi with nerf for novel view synthesis. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 12578-12588, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.576, + 0.892, + 0.631 + ], + "angle": 0, + "content": "[16] Junnan Li, Dongxu Li, Silvio Savarese, and Steven Hoi. Blip-2: Bootstrapping language-image pre-training with frozen image encoders and large language models. arXiv preprint arXiv:2301.12597, 2023. 4, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.633, + 0.892, + 0.673 + ], + "angle": 0, + "content": "[17] Qinbo Li and Nima Khademi Kalantari. Synthesizing light field from a single image with variable mpi and two network fusion. ACM Trans. Graph., 39(6):229-1, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.676, + 0.892, + 0.743 + ], + "angle": 0, + "content": "[18] Chen-Hsuan Lin, Jun Gao, Luming Tang, Towaki Takikawa, Xiaohui Zeng, Xun Huang, Karsten Kreis, Sanja Fidler, Ming-Yu Liu, and Tsung-Yi Lin. Magic3d: High-resolution text-to-3d content creation. arXiv preprint arXiv:2211.10440, 2022. 2, 3, 4, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.746, + 0.892, + 0.813 + ], + "angle": 0, + "content": "[19] Miaomiao Liu, Xuming He, and Mathieu Salzmann. Geometry-aware deep network for single-image novel view synthesis. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4616-4624, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.817, + 0.892, + 0.871 + ], + "angle": 0, + "content": "[20] Stephen Lombardi, Tomas Simon, Jason Saragih, Gabriel Schwartz, Andreas Lehrmann, and Yaser Sheikh. Neural volumes: Learning dynamic renderable volumes from images. arXiv preprint arXiv:1906.07751, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.874, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[21] Roey Mechrez, Itamar Talmi, and Lihi Zelnik-Manor. The contextual loss for image transformation with non-aligned" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.519, + 0.937 + ], + "angle": 0, + "content": "22827" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.469, + 0.12 + ], + "angle": 0, + "content": "data. In Proceedings of the European conference on computer vision (ECCV), pages 768-783, 2018. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.121, + 0.47, + 0.175 + ], + "angle": 0, + "content": "[22] Gal Metzer, Elad Richardson, Or Patashnik, Raja Giryes, and Daniel Cohen-Or. Latent-nerf for shape-guided generation of 3d shapes and textures. arXiv preprint arXiv:2211.07600, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.177, + 0.469, + 0.244 + ], + "angle": 0, + "content": "[23] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.246, + 0.469, + 0.302 + ], + "angle": 0, + "content": "[24] Nasir Mohammad Khalid, Tianhao Xie, Eugene Belilovsky, and Tiberiu Popa. Clip-mesh: Generating textured meshes from text using pretrained image-text models. In SIGGRAPH Asia 2022 Conference Papers, pages 1-8, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.303, + 0.469, + 0.357 + ], + "angle": 0, + "content": "[25] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Transactions on Graphics (ToG), 41(4):1-15, 2022. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.359, + 0.469, + 0.412 + ], + "angle": 0, + "content": "[26] Alex Nichol, Heewoo Jun, Prafulla Dhariwal, Pamela Mishkin, and Mark Chen. Point-e: A system for generating 3d point clouds from complex prompts. arXiv preprint arXiv:2212.08751, 2022. 1, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.414, + 0.469, + 0.496 + ], + "angle": 0, + "content": "[27] Michael Niemeyer, Jonathan T Barron, Ben Mildenhall, Mehdi SM Sajjadi, Andreas Geiger, and Noha Radwan. Regnerf: Regularizing neural radiance fields for view synthesis from sparse inputs. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5480-5490, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.498, + 0.469, + 0.538 + ], + "angle": 0, + "content": "[28] Simon Niklaus, Long Mai, Jimei Yang, and Feng Liu. 3d ken burns effect from a single image. ACM Transactions on Graphics (ToG), 38(6):1-15, 2019. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.539, + 0.469, + 0.594 + ], + "angle": 0, + "content": "[29] Kyle Olszewski, Sergey Tulyakov, Oliver Woodford, Hao Li, and Linjie Luo. Transformable bottleneck networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7648-7657, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.595, + 0.469, + 0.649 + ], + "angle": 0, + "content": "[30] Xingang Pan, Bo Dai, Ziwei Liu, Chen Change Loy, and Ping Luo. Do 2d gans know 3d shape? unsupervised 3d shape reconstruction from 2d image gans. arXiv preprint arXiv:2011.00844, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.651, + 0.469, + 0.719 + ], + "angle": 0, + "content": "[31] Eunbyung Park, Jimei Yang, Ersin Yumer, Duygu Ceylan, and Alexander C Berg. Transformation-grounded image generation network for novel 3d view synthesis. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3500-3509, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.721, + 0.469, + 0.762 + ], + "angle": 0, + "content": "[32] Ben Poole, Ajay Jain, Jonathan T Barron, and Ben Mildenhall. Dreamfusion: Text-to-3d using 2d diffusion. arXiv preprint arXiv:2209.14988, 2022. 2, 3, 4, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.763, + 0.469, + 0.844 + ], + "angle": 0, + "content": "[33] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International conference on machine learning, pages 8748-8763. PMLR, 2021. 2, 3, 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.469, + 0.899 + ], + "angle": 0, + "content": "[34] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022. 2" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.133 + ], + "angle": 0, + "content": "[35] René Ranftl, Alexey Bochkovskiy, and Vladlen Koltun. Vision transformers for dense prediction. ArXiv preprint, 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.191 + ], + "angle": 0, + "content": "[36] Konstantinos Rematas, Chuong H Nguyen, Tobias Ritschel, Mario Fritz, and Tinne Tuytelaars. Novel views of objects from a single image. IEEE transactions on pattern analysis and machine intelligence, 39(8):1576-1590, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.193, + 0.892, + 0.234 + ], + "angle": 0, + "content": "[37] Chris Rockwell, David F. Fouhey, and Justin Johnson. Pixelsynth: Generating a 3d-consistent experience from a single image. In ICCV, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.236, + 0.892, + 0.305 + ], + "angle": 0, + "content": "[38] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684-10695, 2022. 1, 2, 4, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.307, + 0.892, + 0.39 + ], + "angle": 0, + "content": "[39] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022. 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.392, + 0.892, + 0.447 + ], + "angle": 0, + "content": "[40] Jonathan Shade, Steven Gortler, Li-wei He, and Richard Szeliski. Layered depth images. In Proceedings of the 25th annual conference on Computer graphics and interactive techniques, pages 231–242, 1998. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.449, + 0.892, + 0.516 + ], + "angle": 0, + "content": "[41] Meng-Li Shih, Shih-Yang Su, Johannes Kopf, and Jia-Bin Huang. 3d photography using context-aware layered depth inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8028-8038, 2020. 1, 3, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.519, + 0.892, + 0.574 + ], + "angle": 0, + "content": "[42] Vincent Sitzmann, Michael Zollhöfer, and Gordon Wetzstein. Scene representation networks: Continuous 3d-structure-aware neural scene representations. Advances in Neural Information Processing Systems, 32, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.577, + 0.892, + 0.646 + ], + "angle": 0, + "content": "[43] Pratul P Srinivasan, Richard Tucker, Jonathan T Barron, Ravi Ramamoorthi, Ren Ng, and Noah Snively. Pushing the boundaries of view extrapolation with multiplane images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 175-184, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.647, + 0.892, + 0.716 + ], + "angle": 0, + "content": "[44] Pratul P Srinivasan, Tongzhou Wang, Ashwin Sreelal, Ravi Ramamoorthi, and Ren Ng. Learning to synthesize a 4d rgbd light field from a single image. In Proceedings of the IEEE International Conference on Computer Vision, pages 2243-2251, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.718, + 0.892, + 0.786 + ], + "angle": 0, + "content": "[45] Shao-Hua Sun, Minyoung Huh, Yuan-Hong Liao, Ning Zhang, and Joseph J Lim. Multi-view to novel view: Synthesizing novel views with self-learned confidence. In Proceedings of the European Conference on Computer Vision (ECCV), pages 155–171, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.789, + 0.892, + 0.844 + ], + "angle": 0, + "content": "[46] Alex Trevithick and Bo Yang. Grf: Learning a general radiance field for 3d representation and rendering. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 15182-15192, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.846, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[47] Richard Tucker and Noah Snively. Single-view view synthesis with multiplane images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 551-560, 2020. 1, 3" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.519, + 0.937 + ], + "angle": 0, + "content": "22828" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[48] Shubham Tulsiani, Richard Tucker, and Noah Snavely. Layer-structured 3d scene inference via view synthesis. In Proceedings of the European Conference on Computer Vision (ECCV), pages 302–317, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.149, + 0.469, + 0.189 + ], + "angle": 0, + "content": "[49] Aaron Van Den Oord, Oriol Vinyals, et al. Neural discrete representation learning. Advances in neural information processing systems, 30, 2017. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.191, + 0.469, + 0.245 + ], + "angle": 0, + "content": "[50] Haochen Wang, Xiaodan Du, Jiahao Li, Raymond A Yeh, and Greg Shakhnarovich. Score jacobian chaining: Lifting pretrained 2d diffusion models for 3d generation. arXiv preprint arXiv:2212.00774, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.247, + 0.469, + 0.302 + ], + "angle": 0, + "content": "[51] Tengfei Wang, Bo Zhang, Ting Zhang, Shuyang Gu, Jianmin Bao, Tadas Baltrusaitis, Jingjing Shen, Dong Chen, Fang Wen, Qifeng Chen, et al. Rodin: A generative model for sculpting 3d digital avatars using diffusion. CVPR, 2023. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.303, + 0.469, + 0.343 + ], + "angle": 0, + "content": "[52] Tengfei Wang, Ting Zhang, Bo Zhang, Hao Ouyang, Dong Chen, Qifeng Chen, and Fang Wen. Pretraining is all you need for image-to-image translation. In arXiv, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.344, + 0.469, + 0.399 + ], + "angle": 0, + "content": "[53] Daniel Watson, William Chan, Ricardo Martin-Brualla, Jonathan Ho, Andrea Tagliasacchi, and Mohammad Norouzi. Novel view synthesis with diffusion models. arXiv preprint arXiv:2210.04628, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.401, + 0.469, + 0.468 + ], + "angle": 0, + "content": "[54] Olivia Wiles, Georgia Gkioxari, Richard Szeliski, and Justin Johnson. Synsin: End-to-end view synthesis from a single image. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7467-7477, 2020. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.47, + 0.469, + 0.51 + ], + "angle": 0, + "content": "[55] Jiaxin Xie, Hao Ouyang, Jingtan Piao, Chenyang Lei, and Qifeng Chen. High-fidelity 3d gan inversion by pseudomulti-view optimization. CVPR, 2023. 1, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.512, + 0.469, + 0.594 + ], + "angle": 0, + "content": "[56] Dejia Xu, Yifan Jiang, Peihao Wang, Zhiwen Fan, Humphrey Shi, and Zhangyang Wang. Sinnerf: Training neural radiance fields on complex scenes from a single image. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXII, pages 736-753. Springer, 2022. 1, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.596, + 0.469, + 0.636 + ], + "angle": 0, + "content": "[57] Dejia Xu, Yifan Jiang, Peihao Wang, Zhiwen Fan, Yi Wang, and Zhangyang Wang. Neurallift-360: Lifting an in-the-wild 2d photo to a 3d object with \\(360^{\\circ}\\) views. 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.638, + 0.469, + 0.704 + ], + "angle": 0, + "content": "[58] Lior Yariv, Yoni Kasten, Dror Moran, Meirav Galun, Matan Atzmon, Basri Ronen, and Yaron Lipman. Multiview neural surface reconstruction by disentangling geometry and appearance. Advances in Neural Information Processing Systems, 33:2492-2502, 2020. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.707, + 0.469, + 0.773 + ], + "angle": 0, + "content": "[59] Alex Yu, Vickie Ye, Matthew Tancik, and Angjoo Kanazawa. pixelnerf: Neural radiance fields from one or few images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4578-4587, 2021. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.776, + 0.469, + 0.831 + ], + "angle": 0, + "content": "[60] Jiahui Yu, Zhe Lin, Jamei Yang, Xiaohui Shen, Xin Lu, and Thomas S Huang. Free-form image inpainting with gated convolution. In Proceedings of the IEEE/CVF international conference on computer vision, pages 4471-4480, 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.833, + 0.469, + 0.9 + ], + "angle": 0, + "content": "[61] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 586-595, 2018. 8" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.162 + ], + "angle": 0, + "content": "[62] Tinghui Zhou, Shubham Tulsiani, Weilun Sun, Jitendra Malik, and Alexei A Efros. View synthesis by appearance flow. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part IV 14, pages 286-301. Springer, 2016. 2" + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.519, + 0.937 + ], + "angle": 0, + "content": "22829" + } + ] +] \ No newline at end of file diff --git a/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/3c32b216-e73e-471f-8cad-0ce51b8a9a7c_origin.pdf b/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/3c32b216-e73e-471f-8cad-0ce51b8a9a7c_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..a637b667339ed25324e74b68c2920c3ffecce653 --- /dev/null +++ b/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/3c32b216-e73e-471f-8cad-0ce51b8a9a7c_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:ab38c83a6ee77770cfd28c83af038814fd8df02c1c1f0fcfd692cff2695ee69a +size 8523684 diff --git a/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/full.md b/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/full.md new file mode 100644 index 0000000000000000000000000000000000000000..0bec5226c7d51a7925af66dea444ce48dcae3f9e --- /dev/null +++ b/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/full.md @@ -0,0 +1,412 @@ +# Make-It-3D: High-Fidelity 3D Creation from A Single Image with Diffusion Prior + +Junshu Tang $^{1\dagger}$ Tengfei Wang $^{2\dagger}$ Bo Zhang $^{3‡}$ Ting Zhang $^{3}$ + +Ran Yi $^{1}$ Lizhuang Ma $^{1\ddagger}$ Dong Chen $^{3}$ + +$^{1}$ Shanghai Jiao Tong University $^{2}$ HKUST $^{3}$ Microsoft Research + +https://make-it-3d.github.io/ + +![](images/e54bedeb393467444c8b6236dc07517aec8c9ad89da743d7aa84311408eceb5c.jpg) +Reference + +![](images/d6988a0e37b398c91d743993ae325f8abaf3009b5cd63f6585e4ddaba4694c33.jpg) + +![](images/06d8e89be7e724c061996062c71feb68bbecd45286463d1415674c6c1804fa61.jpg) +Normal + +![](images/c8ddbe1d4ca6ed848a8c7d2d8f64ec292e21e007c1f295d9ef81a729ad6b266e.jpg) + +![](images/7315f1d333501f5ee13361beca23f10de0377066f33f35bbcefc56c6a42d8850.jpg) +Figure 1: Make-It-3D can create high-fidelity 3D content from only a single image. We show the normal map and novel-view renderings of created 3D content, showcasing fine geometry and faithful textures with stunning quality at novel views. + +![](images/deee086095831a77801779b79f040b80ab1e5dd32ad409e107ad8a56e47989cb.jpg) + +![](images/46467de6d7a713ed4f9f698b7fdf55131b9076b7319b701e60af864fa2169988.jpg) +Novel Views + +![](images/c44196c384e8057e4868b8725f5fcc8ed870cb91b7156a49cfb588d89d497ee2.jpg) +Reference + +![](images/b466c4cbe7820bf5365c701cd8f1b6e36bd3fedfa392a00c24a7abb50d45a98c.jpg) + +![](images/7b449617522578647040ecfede2f1e60e4035daa8dcc27830f52bc386266f428.jpg) +Normal + +![](images/1528522dda3176fdd420078451dc2aafc08d8debb7c77d0e3f117de9112d6c53.jpg) + +![](images/8ea39c7950b4dc4d78171a37214866f44d905eec2216782355e74c31012ec1d8.jpg) +Novel Views + +![](images/4b4ac5070eafd52ae7825894c666cd449c231a143244024f4b022565aa462d14.jpg) + +![](images/91113be4f7afec537cc6ef0069c12164fed42fd03dcaeb032e41fa4b02d48104.jpg) + +# Abstract + +In this work, we investigate the problem of creating high-fidelity 3D content from only a single image. This is inherently challenging: it essentially involves estimating the underlying 3D geometry while simultaneously hallucinating unseen textures. To address this challenge, we leverage prior knowledge from a well-trained 2D diffusion model to act as 3D-aware supervision for 3D creation. Our approach, Make-It-3D, employs a two-stage optimization pipeline: the first stage optimizes a neural radiance field by incorporating constraints from the reference image at the frontal view and diffusion prior at novel views; the second stage transforms the coarse model into textured point clouds and further elevates the realism with diffusion prior while leveraging the high-quality textures from the reference image. Extensive experiments demonstrate that our method outperforms prior works by a large margin, resulting in faithful reconstructions and impressive visual quality. Our method presents the first attempt to achieve high-quality 3D creation from a single image for general objects and enables various applications such as text-to-3D creation and texture editing. + +# 1. Introduction + +Given a single image as in Figure 1, how would the object portrayed in the image look like from a different perspective? Humans possess an innate ability to effortlessly imagine 3D geometry and hallucinate the appearance of novel views with a glance at the picture based on their prior knowledge about the world. In this work, we aim to achieve a similar goal: creating high-fidelity 3D content from a real or artificially generated single image. This will open up new avenues for artistic expression and creativity, such as bringing 3D effects to the fantasy images given by the cutting-edge 2D generative models like Stable Diffusion [38]. By offering a more accessible and automated way to create visually stunning 3D content, we hope to engage a broader audience with the world of 3D modeling with ease. + +The creation of 3D objects from a single image presents a significant challenge due to the limited information that can be inferred from a single viewpoint. One categories of works aim to produce 3D photo effect [28, 41, 11, 47] in the manner of image-based rendering or single-view 3D reconstruction with neural rendering [54, 56, 37]. However, these methods often struggle with reconstructing fine geometry and fall short of rendering in large views. Another line of research [26, 51, 59, 55] projects the input image into the latent space of the pretrained 3D-aware generative networks. + +Despite their impressive performance, the existing 3D generative networks mainly model objects from a specific class and are therefore incapable of handling general 3D objects. In our case, we aim for general 3D creation from an arbitrary image, yet constructing a sufficiently large and diverse dataset for estimating the novel views or building a powerful 3D foundation model for general objects remains insurmountable. + +Unlike the scarcity of 3D models, images are much more readily available, and recent advancements in diffusion models have sparked a revolution in 2D image generation [34, 39, 38, 52, 4]. Interestingly, we observed that well-trained image diffusion models can generate images under various views, which implies that they have already incorporated 3D knowledge. This has motivated us to explore the possibility of cultivating prior knowledge in a 2D diffusion model to reconstruct 3D objects. With diffusion prior, we propose Make-It-3D, a two-stage 3D content creation method that can generate a high-fidelity 3D object with superior quality from only one image. + +In the first stage, we leverage diffusion prior to optimize a neural radiance field (NeRF) [23] by applying score distillation sampling (SDS) [32], and constrain this optimization with reference-view supervision. Different from prior text-to-3D works [32, 18, 22], we focus on image-based 3D creation so that we need to prioritize the faithfulness to the reference image. However, we observed that while 3D models generated with SDS match text prompts well, they often fail to align faithfully with reference images since textual descriptions do not capture all object details. To address this issue, we go beyond SDS by simultaneously maximizing the image-level similarity between the reference and the novel view rendering denoised by a diffusion model. Also, as images inherently capture more geometry-related information than textual descriptions, we can thus incorporate the depth of the reference image as an extra geometry prior to alleviate the shape ambiguity of NeRF optimization. + +While the first stage generates a coarse model with plausible geometry, its appearance often deviates from the quality of the reference, exhibiting over-smooth textures and saturated colors [32]. This has limited its overall realism, and it is imperative to further bridge the gap between coarse model and reference image. As texture is more critical than geometry for human perception in the context of high-quality rendering, we choose to prioritize texture enhancement in the second stage, while inheriting the geometry from the first stage. We refine the model by leveraging the availability of ground-truth textures for regions that are observable in the reference image. To achieve this, we export the coarse NeRF model to textured point clouds and project reference textures onto their corresponding areas in the point clouds. We then utilize diffusion prior to enhance the texture of the remaining points by jointly optimizing + +the point feature and a point cloud renderer, resulting in a clearly improved texture of the generated 3D model. + +With diffusion prior as multi-view supervision, our approach can be applied to general objects without being limited to specific categories. To evaluate the method, we create a benchmark consisting of 400 images including both real images and generated images from 2D diffusion. We evaluate the proposed method on public DTU dataset [1] and our benchmark, and extensive experiments show a clear improvement over previous works. Furthermore, our method enables a range of applications beyond image-to-3D creation such as texture editing and high-quality text-to-3D creation. Our main contributions are summarized as: + +- We propose Make-It-3D, a framework to create a high-fidelity 3D object from a single image, using a 2D diffusion model as 3D-aware prior. It does not require multi-view images for training and can be applied to any input image, whether it is real or generated. +- With a two-stage creation scheme, Make-It-3D represents the first work to achieve high-fidelity 3D creation for general objects. The resulting 3D models exhibit detailed geometry and realistic textures that accurately conform to the reference images. +- Beyond image-to-3D creation, our method enables multiple applications such as high-quality text-to-3D creation and texture editing. + +# 2. Related Work + +Novel view synthesis from a few images. Early attempts [14, 6, 45, 31] usually require dense observations of a scene from uniformly sampled poses. Recent emergence of implicit representations [42, 23] significantly advances the synthesis quality of novel views, whereas they tend to find a degenerate solution when given only very few input views. To enable novel view from sparse input views, a growing body of works [20, 46, 27] hence turn to extra prior knowledge as additional regularizations. PixelNeRF [59] predicts a continuous neural representation conditioned on the input images rather than only leveraging input views for supervision. DietNeRF [10] penalizes a semantic consistency loss by minimizing distance between CLIP [33] features of different views. With recent rapid progress of diffusion models, 3DiM [53] introduces a pose-conditional diffusion model that generates a novel view conditioned on a source view and a target pose. RenderDiffusion [3] presents a diffusion model for 3D generation that incorporates a triplane rendering mode into the denoiser. + +Single-image 3D photography. Synthesizing novel views from a single image is quite challenging as it is a highly ill-posed problem, requiring precise geometry estimation and disocclusion of both geometry and texture. Increasing effort has been dedicated to this problem [62, 7, 19, 29, 31, 36, 28, 44], many of which can only handle specific types. Among + +![](images/7d774c4c5614db15c5362007b10d97d916661e68ae59ce0811427f18556af359.jpg) +1. Coarse Stage +Reference + +![](images/4593f30bc501fcd83b611a5c949cd88093b26139172d144ed030f4bb4a496634.jpg) +Neural Radiance Field + +![](images/d8d9f51668e36cb6a078665b44ec8697780ff6c4c010b9ea84f5da4d7e386fb0.jpg) + +![](images/bb8be0325ef351153c5332449b2a77a15c68becfaee3d7a7b9d862a0be6ff756.jpg) +Novel + +![](images/2c38c99e723df4fcfbb294b96af57eedf2b7a181f62f923ada079a2ed5ff1ecd.jpg) +Reference + +![](images/d29f64a74478541c3423fc56a17e6a485f568ba8ded840576ea2e279f61a303f.jpg) +view +views +A brown teddy bear sitting on a ground. + +![](images/823a480f4417fbd883ff5da354595ff480597c601dbb23141667a9e92f715c69.jpg) +$\mathcal{L}_{ref}, \mathcal{L}_{depth}$ + +![](images/b57e40bb396b9b7ceb0c48c3f46ec07eb1505c26b7a1224cf96318c237867545.jpg) + +![](images/05fb9987fe16058162735ea7722eafa54434db1ed553242514b073246989dd1e.jpg) + +![](images/a9c7c4e002951609e3fcf1df9fbe116a7abc06333719a8584cd93622c26fd75a.jpg) +Estimated +Depth + +![](images/3c577e15e791eec6d36cd64ea1af85ca419e68fc15fbec4265d02e27bd1f6c2f.jpg) +Masked +Reference + +![](images/845a25496e250705aeaf72b1d3b2515720a2b6262aa0a7b564225c5045527477.jpg) +2. Refine Stage +Image Caption Model + +![](images/d4b886cfe4224543edf80ae17a93c703c4d6fe8816392eba84a6b88e6a3420b3.jpg) +Figure 2: Overview architecture. We propose a two-stage framework for creating a high-quality 3D model from a reference image with diffusion prior (Sec. 3.1). At the coarse stage, we optimize a NeRF for reconstructing the geometry of the reference image (Sec. 3.2). We further build textured point clouds from NeRF and the reference image, and jointly optimize the texture of invisible points and a learnable deferred renderer to generate realistic and view-consistent textures (Sec. 3.3). + +![](images/2caf905e558ed575170d96a958fe7fd2f966219bed7d7357b5dc26682bde9913.jpg) +Invisible Points +# +# +Textured Point Clouds + +![](images/f6a4055fb428f0e0099ad9a27f22ddd56b49ba8895c347752ce93e838ab6d98a.jpg) +# + +![](images/ebd11aedfb73f6f632ced0e7d7e00415ea6fb13d7f5e433b8b68e24578864de9.jpg) +XX +Descriptors + +![](images/1f924942d4ec7baea6a12190aa438f2b4563f4ae640fddceb162d6df64f89704.jpg) +Z-buffer & Rasterization +Deferred Renderer + +![](images/94ea0028c0a1a7f7a0422a876bac7a8002d8c38d97f7271bc6c368aa0a088ba8.jpg) +Enhanced Output + +them, a number of methods rely on layered representations such as layered depth images [40, 48, 41] and multi-plane images (MPIs) [43, 47, 17, 8]. For example, [47] predicts MPIs for view synthesis from single image without requiring ground truth 3D. [41] generates a 3D photo from a given RGB-D input through layered depth image with inpainted color and depth. Yet such a solution is limited by the number of planes and sensitive to discontinuities. Subsequent efforts generalize MPIs to continuous 3D representations such as NeRF [15] and latent 3D point cloud [54]. + +Lift 2D pretrained model to 3D. With the emergence of recent advances in modeling natural image manifold, how to exploit such powerful 2D pretrained model to recover 3D object structure has received considerable research interest. [30] attempts to reconstruct the 3D shape using pretrained 2D GANs. Subsequently, some works [9, 13, 24] explore zero-shot text-guided 3D content creation utilizing the guidance from CLIP [33]. Recent efforts such as DreamFusion [32], Magic3D [18] and Score Jacobian Chaining [50] explore text-to-3D generation by exploiting a score distillation sampling (SDS) loss derived from a 2D text-to-image diffusion model instead, showing impressive results. LatentNeRF [22] proposes to use a shape prior to guide and assist the 3D generation directly in the latent space + +of the diffusion model. Prior works NeuralLift-360 [57] and NeRDi [5] also leverage the generative prior for 3D reconstruction from a single view. Yet the reconstructed 3D model has limited quality and is poorly aligned with the input image. In contrast, we propose a two-stage 3D synthesis framework with a relaxed SDS loss, yielding high-quality 3D representation faithful to the given input image. + +# 3. Method + +Generating novel views for general scenes or objects from only a single image is inherently challenging due to the difficulty of inferring both geometry and missing texture. We therefore tackle this challenge by cultivating the dark knowledge of pretrained 2D diffusion models. Specifically, given an input image $\pmb{x}$ , we first hallucinate its underlying 3D representation, neural radiance field (NeRF), whose rendering appears as a plausible sample to a pretrained denoising diffusion model, and we constrain this optimization process with the texture and depth supervision at the reference view. To further improve the rendering realism, we keep the learned geometry and enhance the textures with the reference image. As such, in the second stage, we lift the input image to textured point clouds and focus on refining the color of the points occluded in the reference view. + +We leverage prior knowledge of the text-to-image generative model and the text-image contrastive model for both stages. In this way, we achieve a faithful 3D representation of the input image with restored high-fidelity texture and geometry. The proposed two-stage 3D learning framework is illustrated in Figure 2. We will subsequently brief the preliminaries and then detail our method. + +# 3.1. Preliminaries + +Recent findings show that pretrained 2D generative models offer rich 3D geometry knowledge for their 2D generation samples. Notably, DreamFusion [32] uses a text-to-image diffusion model to guide the optimization of the 3D representation. Let $\mathcal{G}_{\theta}(\beta)$ be the rendered image at the given viewpoint $\beta$ , where $\mathcal{G}$ is the differentiable rendering function for the 3D representation parameterized by $\theta$ and is amenable to choice. DreamFusion optimizes the neural radiance field such that its multi-view renderings look like high-quality samples from a frozen diffusion model. + +Specifically, a diffusion model $\epsilon_{\phi}$ introduces a random amount of noise $\epsilon$ to the rendered image $\pmb{x}_0 \coloneqq \mathcal{G}_{\theta}(\beta)$ at different timestep $t$ , i.e., $\pmb{x}_t = \alpha_t \pmb{x}_0 + \sigma_t \pmb{\epsilon}$ , where $\epsilon \sim \mathcal{N}(\mathbf{0}, \mathbf{I})$ ; $\alpha_t$ and $\sigma_t$ define a noise schedule whose log signal-to-noise ratio $\lambda_t = \log[\alpha_t^2 / \sigma_t^2]$ linearly decreases with the timestep $t$ . A pretrained text-conditioned diffusion model is trained to reverse this noising process given the text embedding $\pmb{y}$ . To optimize the 3D representation parameters to render images as close as good generation samples, a score distillation sampling (SDS) loss $\mathcal{L}_{\mathrm{SDS}}$ is introduced to push rendered images toward higher density region conditioned on the text embedding. Specifically, $\mathcal{L}_{\mathrm{SDS}}$ computes the difference of predicted noise and the added noise as per-pixel gradient which is used to update the scene parameters, i.e., + +$$ +\nabla_ {\theta} \mathcal {L} _ {\mathrm {S D S}} (\phi , \mathcal {G} _ {\theta}) = \mathbb {E} _ {t, \epsilon} \left[ w (t) \left(\epsilon_ {\phi} \left(\boldsymbol {x} _ {t}; \boldsymbol {y}, t\right) - \epsilon\right) \frac {\partial \boldsymbol {x}}{\partial \theta} \right], \tag {1} +$$ + +where $w(t)$ is a weight function of different noise levels. It can be proved that this loss essentially measures the similarity between the image and the text prompt. The diffusion model acts as a critic and the gradient of $\mathcal{L}_{\mathrm{SDS}}$ will not be back-propagated through the diffusion network, resulting in efficient computation. As training proceeds, the NeRF parameters are updated during which the 3D object gradually reveals its texture and geometry. In practice, it is found that using a diffusion model with a strong classifier-free guidance leads to higher-quality 3D samples. + +While DreamFusion uses the Imagen [39] to reverse the noising process at the pixel level, we use the publicly available Stable Diffusion [38] that models the latent space of the VQ-VAE [49] with an encoder $\mathcal{E}$ and a decoder $\mathcal{D}$ . Hence, the used diffusion model digests the latent $z_0 \coloneqq \mathcal{E}(\mathcal{G}_{\theta}(\beta))$ and the reconstructed latent $\hat{z}_0$ can be mapped to image space through $\hat{\boldsymbol{x}} = \mathcal{D}(\hat{z}_0)$ . + +![](images/fbf2adf1b329cc31af3ac5e4dce2323c42cbb509632637866c1b95eea0f08402.jpg) +Figure 3: Analysis on the coarse stage. Baseline is a naive solution using only $\mathcal{L}_{\mathrm{SDS}}$ and $\mathcal{L}_{\mathrm{ref}}$ , and it does not match the reference well. With $\mathcal{L}_{\mathrm{CLIP-D}}$ , the result aligns better with the reference. The depth prior further improves faithfulness. + +# 3.2. Coarse Stage: Single-view 3D Reconstruction + +As the first stage, we reconstruct a coarse NeRF from the single reference image $\pmb{x}$ with the diffusion prior constraining the novel views. Our optimization is expected to meet the following requirements simultaneously: 1) the optimized 3D representation should closely resemble the rendering appearance of the input observation $\pmb{x}$ at the reference view; 2) the novel view renderings should demonstrate consistent semantics with the input and appear as plausible as possible; 3) the generated 3D model should exhibit compelling geometry. In view of these, we randomly sample the camera poses around the reference view and enforce constraints upon the rendered images $\mathcal{G}_{\theta}$ for both the reference view and unseen views. + +Reference view per-pixel loss. To encourage consistent appearance with the input image, we penalize the pixel-wise difference between the rendering and the input image at the reference view $\beta_{\mathrm{ref}}$ : + +$$ +\mathcal {L} _ {\text {r e f}} = \left\| \boldsymbol {x} \odot \boldsymbol {m} - \mathcal {G} _ {\theta} \left(\beta_ {\text {r e f}}\right) \right\| _ {1}. \tag {2} +$$ + +Here we apply the foreground matting mask $\pmb{m}$ to segment out the foreground as we empirically find that this eases the geometry reconstruction, which conforms to [58]. + +Diffusion prior. Optimizing with the aforementioned losses can be unstable and may lead to implausible results, due to the ill-posed nature of the problem. In order to encourage semantically plausible results, additional constraints are needed on the novel view rendering. To tackle this challenge, we resort to the diffusion prior. Prior works on text-to-3D [32, 18] applied $\mathcal{L}_{\mathrm{SDS}}$ to leverage text-conditioned diffusion models as 3D-aware prior. To utilize $\mathcal{L}_{\mathrm{SDS}}$ in our case, we use an image captioning model [16], to generate a detailed text description $y$ for the reference image. With the text prompt $y$ , we can perform the SDS on the latent space of Stable Diffusion, + +$$ +\nabla_ {\theta} \mathcal {L} _ {\mathrm {S D S}} (\phi , \mathcal {G} _ {\theta}) = \mathbb {E} _ {t, \epsilon} \left[ w (t) \left(\epsilon_ {\phi} \left(\boldsymbol {z} _ {t}; \boldsymbol {y}, t\right) - \epsilon\right) \frac {\partial \boldsymbol {z}}{\partial \boldsymbol {x}} \frac {\partial \boldsymbol {x}}{\partial \theta} \right], \tag {3} +$$ + +where the noisy latent $\mathbf{z}_t$ is obtained from a novel view rendering $\mathbf{x}$ by Stable Diffusion encoder. + +![](images/26f77c84ab863be0135e9b89c18a1d55a9552c2754e805f517d3606f57f445ca.jpg) +Figure 4: $360^{\circ}$ object reconstruction from real images. + +![](images/dbf70d1db83d4527533f4ccd8f62d019ffeecaa77d68edad489c0fd85ffdff66.jpg) + +![](images/a4cb6bc2e0b8f21893de5df3776fd5a67672e9957df9c4d06fba5f0f66bfb677.jpg) + +![](images/3b180ad83095ad02186250d25a705636024d2d71ba80b6f486f321f0d2b77f74.jpg) + +![](images/55e8c7f061168dbb1898b9fa4577ac3c7dee7584dbb9567a295a411fea9fb6a7.jpg) + +However, as discussed before, $\mathcal{L}_{\mathrm{SDS}}$ essentially measures the similarity between the image and the given text prompt. While $\mathcal{L}_{\mathrm{SDS}}$ can generate 3D models that are faithful to the text prompt, they do not align perfectly with the reference image (see baseline in Figure 3), since text prompts cannot capture all object details. We go beyond this by a diffusion CLIP loss, denoted as $\mathcal{L}_{\mathrm{CLIP-D}}$ , that additionally enforces the generated model to match the reference image: + +$$ +\mathcal {L} _ {\mathrm {C L I P - D}} (\mathcal {X}, \mathcal {G} _ {\theta} (\beta)) = - \mathcal {E} _ {\mathrm {C L I P}} (\mathcal {X}) \cdot \mathcal {E} _ {\mathrm {C L I P}} (\hat {\mathcal {X}} _ {0} (\beta , t)), \tag {4} +$$ + +where $\mathcal{E}_{\mathrm{CLIP}}(\cdot)$ is a CLIP image encoder [33]. Rather than directly measuring CLIP loss on the rendered images $\mathcal{G}_{\theta}(\beta)$ , we encode the novel view rendering $\mathcal{G}_{\theta}(\beta)$ to noisy latent $z_{t}$ and then denoise it to a clean image $\tilde{\mathcal{X}}_0(\beta, t)$ with 2D diffusion. By imposing the similarity loss on denoised images sampled from diffusion models, we encourage the rendering to align with the reference image, while resembling high-quality samples from a frozen diffusion. + +In detail, we do not optimize $\mathcal{L}_{\mathrm{CLIP - D}}$ and $\mathcal{L}_{\mathrm{SDS}}$ at the same time. We use $\mathcal{L}_{\mathrm{CLIP - D}}$ at small timesteps and switch to $\mathcal{L}_{\mathrm{SDS}}$ at large timesteps. More details and analysis are in the Supplement. Combining $\mathcal{L}_{\mathrm{SDS}}$ and $\mathcal{L}_{\mathrm{CLIP - D}}$ , our diffusion prior ensures that the resulting 3D model appears visually appealing and plausible while also conforming to the given image (see Figure 3). + +Depth prior. Nonetheless, even if the rendered image appears meaningful to the diffusion model, there still exists shape ambiguity that brings about issues such as sunken faces, over-flat geometry [32] or depth ambiguity (see Figure 3). We mitigate these by leveraging depth prior learned from abundant external images and directly enforcing the supervision in 3D. To be specific, we utilize an off-the-shelf single-view depth estimator [35] to estimate the depth $d$ for the input image. While the estimated depth may not accurately characterize the geometric detail, it suffices to ensure plausible geometry and resolve most of the ambiguity. To account for the inaccuracy and the scale mismatch in $d$ , akin to [5], we regularize the negative Pearson correlation between the estimated depth and the depth $d(\beta_{\mathrm{ref}})$ modeled by NeRF at the reference viewpoint, i.e., + +$$ +\mathcal {L} _ {\text {d e p t h}} = - \frac {\operatorname {C o v} \left(d \left(\beta_ {\text {r e f}}\right) , d\right)}{\operatorname {V a r} \left(d \left(\beta_ {\text {r e f}}\right)\right) \operatorname {V a r} (d)}, \tag {5} +$$ + +![](images/ab569120f2bab3c1c7de48391a26dbab8ddb9afb5a180b49b6c85f922573e99c.jpg) +Figure 5: Illustration of textured point cloud building. We aim at building dense points and texturing visible points using reference image, and invisible points from NeRF. + +where $\mathrm{Cov}(\cdot)$ denotes the covariance, $\mathrm{Var}(\cdot)$ computes the standard deviation. With this regularization, the NeRF depth estimation is encouraged to be linearly correlated with the depth prior. + +Overall training. The overall loss can be formulated as a combination of $\mathcal{L}_{\mathrm{ref}}$ , $\mathcal{L}_{\mathrm{SDS}}$ , $\mathcal{L}_{\mathrm{CLIP-D}}$ and $\mathcal{L}_{\mathrm{depth}}$ . To stabilize the optimization process, we adopt a progressive training strategy, where we start with a narrow range of views near the reference view and gradually expand the range during training. With progressive training, we can achieve a $360^{\circ}$ reconstruction of an object, as shown in Figure 4. + +# 3.3. Refine Stage: Neural Texture Enhancement + +After the coarse stage, we obtained a 3D model with plausible geometry, but it often displays coarse textures that can bottleneck the overall quality in Figure 6. Further refinement is thus desired for high-fidelity 3D models. Given that humans are more discerning when it comes to texture quality than geometry, we prioritize texture enhancement while preserving the geometry of the coarse model. + +Our key insight for texture enhancement is that for a novel view, certain pixels can be observable in both the novel and reference views. Consequently, we can exploit this overlap to project the high-quality texture of the reference image onto the corresponding areas of the 3D representation. We then focus on enhancing the textures of regions that are occluded in the reference view. + +While NeRF is a suitable representation in the coarse stage as it can handle topological changes continuously, projecting the reference image onto it is challenging. We thus opt to export the neural radiance field to an explicit representation, specifically point clouds. Compared to the noisy mesh exported by marching cube, point clouds offer a cleaner and more straightforward projection. + +Textured point cloud building. A naive attempt to build point clouds is to render multi-view RGBD images from NeRF and lift them to textured points in 3D space. However, we found this simple method leads to noisy point clouds due to the conflict among different views: a 3D point + +![](images/23e1283002c06d3509ca3c7e501a61071643f0fd5d1f7ac298add0ea93177e9c.jpg) +Figure 6: Visualization of neural texture enhancement. We project the reference textures to the coarse model and enhance the remaining regions to high-frequency details consistent with the reference. Best viewed with zoom-in. + +![](images/0064eb298ac99a1797db5c3614d9cdfc828af6475530710b86a1b8e0a1c620c5.jpg) + +![](images/28c8e40a82f7dbb0a1fd180b1141b4b8d51a058b4e9ea7966e11f52eee04055f.jpg) + +![](images/b5b20907eeaf38e9a96ded160117cb4d4b7f0427982cc9648212e2ef623392d9.jpg) + +![](images/640a42b89ce2436a79964101e526c1ae65be753033ac5cdf6dea04b168d815ce.jpg) + +may possess different RGB colors in NeRF rendering under different views [55]. We thus propose an iterative strategy to build clean point clouds from multi-view observations. + +As in Figure 5, we first build point clouds from the reference view $\beta_{\mathrm{ref}}$ according to the rendered depth $\mathcal{D}(\beta_{\mathrm{ref}})$ and alpha mask $M(\beta_{\mathrm{ref}})$ of NeRF, + +$$ +V \left(\beta_ {\text {r e f}}\right) = R _ {\text {r e f}} K ^ {- 1} \mathcal {P} \left(\mathcal {D} \left(\beta_ {\text {r e f}}\right) * M \left(\beta_ {\text {r e f}}\right)\right), \tag {6} +$$ + +where $R_{\mathrm{ref}}$ and $K$ are the extrinsic and intrinsic matrices of the camera, and $\mathcal{P}$ denotes depth-to-point projection. These points are visible under the reference view and thus colorized with ground-truth textures. For the projection of the remaining views $\beta_{i}$ , it is important to avoid introducing points that overlap with existing points but have conflicting colors. To this end, we project the existing points $V(\beta_{\mathrm{ref}})$ to the novel view $\beta_{i}$ to yield a mask indicating the presence of existing points. With this mask as guidance, we only lift those points $V(\beta_{i})$ that have not been observed yet, as shown in Figure 5. These invisible points are then initialized with coarse textures from NeRF rendering $\mathcal{G}(\beta_{i})$ and integrated into the dense point clouds. + +Deferred point cloud rendering. So far, we have built a set of textured point clouds $V = \{V(\beta_{\mathrm{ref}}), V(\beta_1), \dots, V(\beta_N)\}$ . Though $V(\beta_{\mathrm{ref}})$ already have high-fidelity textures projected from the reference image, the other points that are occluded in the reference view still suffer smooth textures from the coarse NeRF, as shown in Figure 6. To enhance the texture, we optimize the texture of the other points and constrain novel-view rendering with diffusion prior. Specifically, we optimize a 19-dimensional descriptor $F$ for each point, whose first three dimensions are initialized with the initial RGB colors. To avoid noisy colors and bleeding artifacts [2], we adopt a multi-scale deferred rendering scheme. In particular, given a novel view $\beta$ , we rasterize the point cloud $\mathbf{V}$ for $K$ times to obtain $K$ feature maps $I_i$ with varying sizes of $[W/2^i, H/2^i]$ , where $i \in [0, K)$ . These feature maps are then concatenated and rendered into an image $\mathbf{I}$ + +
ViewsLPIPS↓Contextual↓CLIP↑
DietNeRF [10]30.18315.3464.90%
SinNeRF [56]10.20594.2873.24%
DreamFusion+ [32]10.40752.1582.81%
Point-E [26]1-2.2371.31%
3D-Photo [41]103.4387.65%
Ours-coarse10.14271.7487.50%
Ours-enhanced10.09081.5995.65%
+ +Table 1: Quantitative comparison on DTU. We compute LPIPS under the reference view, and other two metrics under novel views. LPIPS of Point-E is not reported due to the lack of a defined reference view. + +
LPIPS↓Contextual↓CLIP↑
DreamFusion+ [32]0.56493.0784.08%
Point-E [26]-5.3764.36%
Ours-coarse0.23541.9889.06%
Ours-enhanced0.07801.3395.12%
+ +Table 2: Quantitative comparison on the test benchmark. + +using a U-Net renderer $\mathcal{R}_{\theta}$ [2] that is jointly optimized: + +$$ +I _ {i} (\beta) = \mathcal {S} (i, V, F, \beta), i \in [ 0, K), +$$ + +$$ +\mathbf {I} (\beta) = \mathcal {R} _ {\theta} \left(I _ {0} (\beta), I _ {1} (\beta), \dots , I _ {K - 1} (\beta)\right), \tag {7} +$$ + +where $S$ is a differentiable point rasterizer. The objective of the texture enhancement process is similar to that of the geometry creation discussed in Sec. 3.2, but we additionally include a regularization term that penalizes large differences between the optimized texture and the initial texture. With the texture enhancement process, fine-detailed texture is generated on the occluded points. + +# 4. Experiments + +# 4.1. Implementation Details + +NeRF rendering. We use the multi-scale hash encoding from Instant-NGP [25] to implement the NeRF representation in the coarse optimization stage, which enables neural rendering at a computational cost. Similar to Instant-NGP, we maintain an occupancy grid to enable efficient ray sampling by skipping empty space. Additionally, we adopt several shading augmentations on the rendered images, such as Lambertian and normal shading, akin to [32]. + +Point cloud rendering. For deferred rendering, we use a 2D U-Net architecture with gated convolutions [60]. The dimension of the point descriptor is 19, where the first 3 dimensions are initialized RGB colors and the remaining dimensions are randomly initialized. We also set a learnable descriptor for the background. + +Camera setting. Following the camera sampling method used in [32], we randomly sample novel views with a $75\%$ probability and sample the pre-defined reference view with + +![](images/b29d69849552ba288a44102b49a494deaaa36e5028fa66d0b446221edd1ff428.jpg) +Figure 7: Qualitative comparison on the test benchmark with two diffusion-based 3D content creation models, Dreamfusion and Point-E. We show our results with high-fidelity geometry and texture. The results of Dreamfusion are from its website. + +![](images/be88b9d2a005b48ff33408552c42bb60f9a21679ceeb1fbe3b4522725ffb05da.jpg) +Figure 8: Qualitative comparison of novel view synthesis on DTU with state of the arts. Our method generates sharper and more plausible details in both geometry and texture. + +a $25\%$ probability. We also randomly enlarge the FOV when rendering with NeRF, following [18]. + +Score distillation sampling. We randomly sample $t$ from 0.2 to 0.6, and set $w(t)$ as a uniform weighting depending on the timestep. We also use classifier-free guidance with a guidance weight $\omega : \hat{\epsilon}_{\phi}(z_t; y, t) = (1 + \omega)\epsilon_{\phi}(z_t; y, t) - \omega \epsilon_{\phi}(z_t; t)$ . Our method aims to align the created 3D model with the input image, and we use a guidance weight $\omega = 10$ . Training speed. We use Adam [12] with a learning rate of 0.001 for both stages. The coarse stage is trained for 5,000 iterations at a rendering resolution of $100 \times 100$ . The refine stage then takes another 5,000 iterations at a rendering resolution of $800 \times 800$ . The entire training process takes approximately 2 hours on a single Tesla 32GB V100 GPU. + +Test Benchmark. To the best of our knowledge, we are the first method focusing on high-fidelity 3D creation from an arbitrary image. So we build a test benchmark consisting of 400 images, comprising both real images and images gener- + +
Preference RateGeometry QualityTexture QualityFidelity to Input
Ours/DreamFusion+88.2%/11.8%95.6%/4.4%96.5%/3.5%
+ +Table 3: Preference rate of geometry quality, texture quality, and fidelity to the input image. + +ated by Stable Diffusion [38]. Each image in the benchmark is accompanied by a foreground alpha mask, an estimated depth map, and a text prompt. The text prompts for real images are obtained from an image caption model [16]. We will make this test benchmark publicly available. + +# 4.2. Comparisons with the State of the Arts + +Baselines. We compare our method with five representative baselines. 1) DietNeRF [10], a few-shot NeRF. We train it with three input views. 2) SinNeRF [56], a single-view NeRF method. 3) DreamFusion [32]. As it is originally conditioned on text prompts, we also modify it with image + +![](images/fdb1db10dd726034626928f6b704f9db1937de2efdf114b83d3bfdda716c4fbb.jpg) + +![](images/c9c001c947f2e50eb0c46dc1766dc2509c6b90ede199331059904a1856d7a1f6.jpg) +Figure 9: Make-It-3D enables high-fidelity 3D creation on real complex scenes. +Figure 10: Make-It-3D generates diverse and visually stunning 3D models given a text description. + +reconstruction loss at the reference view, referred as Dream-Fusion+ for fair comparison. 4) Point-E [26], point cloud generation conditioned on image. 5) 3D-Photo [41], depth-based image warping and inpainting method. + +Qualitative comparison. We first compare our method with 3D generation baselines, where DreamFusion and DreamFusion+ leverage 2D diffusion as 3D prior and PointE is a 3D diffusion model. As shown in Figure 7, their generated models fail to align faithfully with the reference image and suffer smooth textures. In contrast, our method produces high-fidelity 3D models with fine geometry and realistic textures. Figure 8 shows additional comparison on novel view synthesis. SinNeRF and DietNeRF encounter difficulties in reconstructing complex objects due to the lack of multi-view supervision. 3D-Photo fails to reconstruct underlying geometry and produces visible artifacts in large views. In comparison, our method achieves remarkably faithful geometry and visually pleasing textures under novel views. + +Quantitative comparison. A compelling generated 3D model should closely resemble the input image at the reference view, and demonstrate consistent semantics with the reference under novel views. We evaluate these two aspects using the following metrics: 1) LPIPS [61], which assesses the reconstruction quality at the reference view, 2) context- + +![](images/b235b34f868e43e6ec4d9f89e1bdf638b2b702ce1248534aeae001dc1700b358.jpg) +Figure 11: Make-It-3D achieves 3D-aware texture modification such as tattoo drawing and stylization. + +tual distance [21], which measures pixel-level similarity between novel-view rendering and the reference, and 3) CLIP score [33], which evaluates the semantic similarity between the novel view and the reference. As shown in Table 1 and Table 2, our approach substantially outperforms baselines in terms of both reference-view and novel-view quality. + +User study. In order to obtain the user's subjective evaluation of the plausibility of the results, we conduct a user study on 30 participants. In the study, we use 25 pairs of results generated by our method and Dreamfusion+, respectively. All results are presented side-by-side and in a random order to participants. Based on the ratings in Table 3, our method outperformed Dreamfusion+ in all aspects. + +# 5. Applications + +Real scene modeling. As shown in Figure 9, Make-It-3D can successfully convert a single photo of a complex scene to a 3D model, such as buildings and landscapes. This empowers users to model a scene with ease, which could be difficult for some traditional 3D modeling techniques. + +High-quality text-to-3D generation with diversity. Prior arts [32, 18] often produce models with limited diversity and excessively smooth textures. To perform high-quality text-to-3D creation, we first convert the text prompt to a reference image using 2D diffusion, and proceed with our image-based 3D creation method. As shown in Figure 10, Make-It-3D is capable of producing diverse examples from a text prompt that exhibit stunning quality. + +3D-aware texture modification. Make-It-3D enables view-consistent texture editing by manipulating the reference image in the refine stage while freezing the geometry. Figure 11 shows that we can add a tattoo and apply stylization to the generated 3D model. + +# 6. Conclusions + +We introduce Make-It-3D, a novel two-stage method for creating high-fidelity 3D content from one single image. Leveraging diffusion prior as 3D-aware supervision, the generated 3D models exhibit faithful geometry and realistic textures with the diffusion CLIP loss and textured point cloud enhancement. Make-It-3D is applicable to general objects, empowering versatile fascinating applications. We believe our method takes a big step in extending the success of 2D content creation to 3D, providing users with a fresh 3D creation experience. + +# 7. Acknowledgement + +The research is supported by National Natural Science Foundation of China (61972157, 72192821), Shanghai Municipal Science and Technology Major Project (2021SHZDZX0102), Shanghai Science and Technology Commission (21511101200), Shanghai Sailing Program (22YF1420300, 23YF1410500) and Young Elite Scientists Sponsorship Program by CAST (2022QNRC001). + +# References + +[1] Henrik Aanaes, Rasmus Ramsbøl Jensen, George Vogiatzis, Engin Tola, and Anders Bjorholm Dahl. Large-scale data for multiple-view stereopsis. International Journal of Computer Vision, pages 1-16, 2016. 2 +[2] Kara-Ali Aliev, Artem Sevastopolsky, Maria Kolos, Dmitry Ulyanov, and Victor Lempitsky. Neural point-based graphics. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XXII 16, pages 696-712. Springer, 2020. 6 +[3] Titas Anciukevicius, Zexiang Xu, Matthew Fisher, Paul Henderson, Hakan Bilen, Niloy J Mitra, and Paul Guerrero. Renderdiffusion: Image diffusion for 3d reconstruction, inpainting and generation. arXiv preprint arXiv:2211.09869, 2022. 2 +[4] Yogesh Balaji, Seungjun Nah, Xun Huang, Arash Vahdat, Jiaming Song, Karsten Kreis, Miika Aittala, Timo Aila, Samuli Laine, Bryan Catanzaro, Tero Karras, and Ming-Yu Liu. ediff-i: Text-to-image diffusion models with an ensemble of expert denoisers. ArXiv, abs/2211.01324, 2022. 2 +[5] Congyue Deng, Chiyu Jiang, Charles R Qi, Xinchen Yan, Yin Zhou, Leonidas Guibas, Dragomir Anguelov, et al. Nerdi: Single-view nerf synthesis with language-guided diffusion as general image priors. arXiv preprint arXiv:2212.03267, 2022. 3, 5 +[6] Steven J Gortler, Radek Grzesczuk, Richard Szeliski, and Michael F Cohen. The lumigraph. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, pages 43-54, 1996. 2 +[7] Tewodros Habtegebrial, Kiran Varanasi, Christian Bailer, and Didier Stricker. Fast view synthesis with deep stereo vision. arXiv preprint arXiv:1804.09690, 2018. 2 + +[8] Yuxuan Han, Ruicheng Wang, and Jiaolong Yang. Single-view synthesis in the wild with learned adaptive multiplane images. In ACM SIGGRAPH 2022 Conference Proceedings, pages 1-8, 2022. 3 +[9] Ajay Jain, Ben Mildenhall, Jonathan T Barron, Pieter Abbeel, and Ben Poole. Zero-shot text-guided object generation with dream fields. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 867-876, 2022. 3 +[10] Ajay Jain, Matthew Tancik, and Pieter Abbeel. Putting nerf on a diet: Semantically consistent few-shot view synthesis. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 5885-5894, 2021. 2, 6, 7 +[11] Varun Jampani, Huiwen Chang, Kyle Sargent, Abhishek Kar, Richard Tucker, Michael Krainin, Dominik Kaeser, William T Freeman, David Salesin, Brian Curless, et al. Slide: Single image 3d photography with soft layering and depth-aware inpainting. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 12518-12527, 2021. 1 +[12] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014.7 +[13] Han-Hung Lee and Angel X Chang. Understanding pure clip guidance for voxel grid nerf models. arXiv preprint arXiv:2209.15172, 2022. 3 +[14] Marc Levoy and Pat Hanrahan. Light field rendering. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, pages 31-42, 1996. 2 +[15] Jiaxin Li, Zijian Feng, Qi She, Henghui Ding, Changhu Wang, and Gim Hee Lee. Mine: Towards continuous depth spi with nerf for novel view synthesis. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 12578-12588, 2021. 3 +[16] Junnan Li, Dongxu Li, Silvio Savarese, and Steven Hoi. Blip-2: Bootstrapping language-image pre-training with frozen image encoders and large language models. arXiv preprint arXiv:2301.12597, 2023. 4, 7 +[17] Qinbo Li and Nima Khademi Kalantari. Synthesizing light field from a single image with variable mpi and two network fusion. ACM Trans. Graph., 39(6):229-1, 2020. 3 +[18] Chen-Hsuan Lin, Jun Gao, Luming Tang, Towaki Takikawa, Xiaohui Zeng, Xun Huang, Karsten Kreis, Sanja Fidler, Ming-Yu Liu, and Tsung-Yi Lin. Magic3d: High-resolution text-to-3d content creation. arXiv preprint arXiv:2211.10440, 2022. 2, 3, 4, 7, 8 +[19] Miaomiao Liu, Xuming He, and Mathieu Salzmann. Geometry-aware deep network for single-image novel view synthesis. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4616-4624, 2018. 2 +[20] Stephen Lombardi, Tomas Simon, Jason Saragih, Gabriel Schwartz, Andreas Lehrmann, and Yaser Sheikh. Neural volumes: Learning dynamic renderable volumes from images. arXiv preprint arXiv:1906.07751, 2019. 2 +[21] Roey Mechrez, Itamar Talmi, and Lihi Zelnik-Manor. The contextual loss for image transformation with non-aligned + +data. In Proceedings of the European conference on computer vision (ECCV), pages 768-783, 2018. 8 +[22] Gal Metzer, Elad Richardson, Or Patashnik, Raja Giryes, and Daniel Cohen-Or. Latent-nerf for shape-guided generation of 3d shapes and textures. arXiv preprint arXiv:2211.07600, 2022. 2, 3 +[23] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021. 2 +[24] Nasir Mohammad Khalid, Tianhao Xie, Eugene Belilovsky, and Tiberiu Popa. Clip-mesh: Generating textured meshes from text using pretrained image-text models. In SIGGRAPH Asia 2022 Conference Papers, pages 1-8, 2022. 3 +[25] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Transactions on Graphics (ToG), 41(4):1-15, 2022. 6 +[26] Alex Nichol, Heewoo Jun, Prafulla Dhariwal, Pamela Mishkin, and Mark Chen. Point-e: A system for generating 3d point clouds from complex prompts. arXiv preprint arXiv:2212.08751, 2022. 1, 6, 8 +[27] Michael Niemeyer, Jonathan T Barron, Ben Mildenhall, Mehdi SM Sajjadi, Andreas Geiger, and Noha Radwan. Regnerf: Regularizing neural radiance fields for view synthesis from sparse inputs. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5480-5490, 2022. 2 +[28] Simon Niklaus, Long Mai, Jimei Yang, and Feng Liu. 3d ken burns effect from a single image. ACM Transactions on Graphics (ToG), 38(6):1-15, 2019. 1, 2 +[29] Kyle Olszewski, Sergey Tulyakov, Oliver Woodford, Hao Li, and Linjie Luo. Transformable bottleneck networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7648-7657, 2019. 2 +[30] Xingang Pan, Bo Dai, Ziwei Liu, Chen Change Loy, and Ping Luo. Do 2d gans know 3d shape? unsupervised 3d shape reconstruction from 2d image gans. arXiv preprint arXiv:2011.00844, 2020. 3 +[31] Eunbyung Park, Jimei Yang, Ersin Yumer, Duygu Ceylan, and Alexander C Berg. Transformation-grounded image generation network for novel 3d view synthesis. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3500-3509, 2017. 2 +[32] Ben Poole, Ajay Jain, Jonathan T Barron, and Ben Mildenhall. Dreamfusion: Text-to-3d using 2d diffusion. arXiv preprint arXiv:2209.14988, 2022. 2, 3, 4, 5, 6, 7, 8 +[33] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International conference on machine learning, pages 8748-8763. PMLR, 2021. 2, 3, 5, 8 +[34] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022. 2 + +[35] René Ranftl, Alexey Bochkovskiy, and Vladlen Koltun. Vision transformers for dense prediction. ArXiv preprint, 2021. 5 +[36] Konstantinos Rematas, Chuong H Nguyen, Tobias Ritschel, Mario Fritz, and Tinne Tuytelaars. Novel views of objects from a single image. IEEE transactions on pattern analysis and machine intelligence, 39(8):1576-1590, 2016. 2 +[37] Chris Rockwell, David F. Fouhey, and Justin Johnson. Pixelsynth: Generating a 3d-consistent experience from a single image. In ICCV, 2021. 1 +[38] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684-10695, 2022. 1, 2, 4, 7 +[39] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022. 2, 4 +[40] Jonathan Shade, Steven Gortler, Li-wei He, and Richard Szeliski. Layered depth images. In Proceedings of the 25th annual conference on Computer graphics and interactive techniques, pages 231–242, 1998. 3 +[41] Meng-Li Shih, Shih-Yang Su, Johannes Kopf, and Jia-Bin Huang. 3d photography using context-aware layered depth inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8028-8038, 2020. 1, 3, 6, 8 +[42] Vincent Sitzmann, Michael Zollhöfer, and Gordon Wetzstein. Scene representation networks: Continuous 3d-structure-aware neural scene representations. Advances in Neural Information Processing Systems, 32, 2019. 2 +[43] Pratul P Srinivasan, Richard Tucker, Jonathan T Barron, Ravi Ramamoorthi, Ren Ng, and Noah Snively. Pushing the boundaries of view extrapolation with multiplane images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 175-184, 2019. 3 +[44] Pratul P Srinivasan, Tongzhou Wang, Ashwin Sreelal, Ravi Ramamoorthi, and Ren Ng. Learning to synthesize a 4d rgbd light field from a single image. In Proceedings of the IEEE International Conference on Computer Vision, pages 2243-2251, 2017. 2 +[45] Shao-Hua Sun, Minyoung Huh, Yuan-Hong Liao, Ning Zhang, and Joseph J Lim. Multi-view to novel view: Synthesizing novel views with self-learned confidence. In Proceedings of the European Conference on Computer Vision (ECCV), pages 155–171, 2018. 2 +[46] Alex Trevithick and Bo Yang. Grf: Learning a general radiance field for 3d representation and rendering. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 15182-15192, 2021. 2 +[47] Richard Tucker and Noah Snively. Single-view view synthesis with multiplane images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 551-560, 2020. 1, 3 + +[48] Shubham Tulsiani, Richard Tucker, and Noah Snavely. Layer-structured 3d scene inference via view synthesis. In Proceedings of the European Conference on Computer Vision (ECCV), pages 302–317, 2018. 3 +[49] Aaron Van Den Oord, Oriol Vinyals, et al. Neural discrete representation learning. Advances in neural information processing systems, 30, 2017. 4 +[50] Haochen Wang, Xiaodan Du, Jiahao Li, Raymond A Yeh, and Greg Shakhnarovich. Score jacobian chaining: Lifting pretrained 2d diffusion models for 3d generation. arXiv preprint arXiv:2212.00774, 2022. 3 +[51] Tengfei Wang, Bo Zhang, Ting Zhang, Shuyang Gu, Jianmin Bao, Tadas Baltrusaitis, Jingjing Shen, Dong Chen, Fang Wen, Qifeng Chen, et al. Rodin: A generative model for sculpting 3d digital avatars using diffusion. CVPR, 2023. 1 +[52] Tengfei Wang, Ting Zhang, Bo Zhang, Hao Ouyang, Dong Chen, Qifeng Chen, and Fang Wen. Pretraining is all you need for image-to-image translation. In arXiv, 2022. 2 +[53] Daniel Watson, William Chan, Ricardo Martin-Brualla, Jonathan Ho, Andrea Tagliasacchi, and Mohammad Norouzi. Novel view synthesis with diffusion models. arXiv preprint arXiv:2210.04628, 2022. 2 +[54] Olivia Wiles, Georgia Gkioxari, Richard Szeliski, and Justin Johnson. Synsin: End-to-end view synthesis from a single image. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7467-7477, 2020. 1, 3 +[55] Jiaxin Xie, Hao Ouyang, Jingtan Piao, Chenyang Lei, and Qifeng Chen. High-fidelity 3d gan inversion by pseudomulti-view optimization. CVPR, 2023. 1, 6 +[56] Dejia Xu, Yifan Jiang, Peihao Wang, Zhiwen Fan, Humphrey Shi, and Zhangyang Wang. Sinnerf: Training neural radiance fields on complex scenes from a single image. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXII, pages 736-753. Springer, 2022. 1, 6, 7 +[57] Dejia Xu, Yifan Jiang, Peihao Wang, Zhiwen Fan, Yi Wang, and Zhangyang Wang. Neurallift-360: Lifting an in-the-wild 2d photo to a 3d object with $360^{\circ}$ views. 2022. 3 +[58] Lior Yariv, Yoni Kasten, Dror Moran, Meirav Galun, Matan Atzmon, Basri Ronen, and Yaron Lipman. Multiview neural surface reconstruction by disentangling geometry and appearance. Advances in Neural Information Processing Systems, 33:2492-2502, 2020. 4 +[59] Alex Yu, Vickie Ye, Matthew Tancik, and Angjoo Kanazawa. pixelnerf: Neural radiance fields from one or few images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4578-4587, 2021. 1, 2 +[60] Jiahui Yu, Zhe Lin, Jamei Yang, Xiaohui Shen, Xin Lu, and Thomas S Huang. Free-form image inpainting with gated convolution. In Proceedings of the IEEE/CVF international conference on computer vision, pages 4471-4480, 2019. 6 +[61] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 586-595, 2018. 8 + +[62] Tinghui Zhou, Shubham Tulsiani, Weilun Sun, Jitendra Malik, and Alexei A Efros. View synthesis by appearance flow. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part IV 14, pages 286-301. Springer, 2016. 2 \ No newline at end of file diff --git a/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/images.zip b/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..70fa492ce73f6b98751835489a3436533d9bc2b7 --- /dev/null +++ b/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:5c02eaa14c92bdf97a0d56352e221adb8112fc58aca54faf639be4e1fd943367 +size 778334 diff --git a/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/layout.json b/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..f4173425437ec06f8865d5720d756db16f2b3d39 --- /dev/null +++ b/2023/Make-It-3D_ High-fidelity 3D Creation from A Single Image with Diffusion Prior/layout.json @@ -0,0 +1,11678 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 47, + 121, + 550, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 121, + 550, + 140 + ], + "spans": [ + { + "bbox": [ + 47, + 121, + 550, + 140 + ], + "type": "text", + "content": "Make-It-3D: High-Fidelity 3D Creation from A Single Image with Diffusion Prior" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 143, + 160, + 449, + 176 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 160, + 449, + 176 + ], + "spans": [ + { + "bbox": [ + 143, + 160, + 449, + 176 + ], + "type": "text", + "content": "Junshu Tang" + }, + { + "bbox": [ + 143, + 160, + 449, + 176 + ], + "type": "inline_equation", + "content": "^{1\\dagger}" + }, + { + "bbox": [ + 143, + 160, + 449, + 176 + ], + "type": "text", + "content": " Tengfei Wang" + }, + { + "bbox": [ + 143, + 160, + 449, + 176 + ], + "type": "inline_equation", + "content": "^{2\\dagger}" + }, + { + "bbox": [ + 143, + 160, + 449, + 176 + ], + "type": "text", + "content": " Bo Zhang" + }, + { + "bbox": [ + 143, + 160, + 449, + 176 + ], + "type": "inline_equation", + "content": "^{3‡}" + }, + { + "bbox": [ + 143, + 160, + 449, + 176 + ], + "type": "text", + "content": " Ting Zhang" + }, + { + "bbox": [ + 143, + 160, + 449, + 176 + ], + "type": "inline_equation", + "content": "^{3}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 204, + 177, + 402, + 190 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 204, + 177, + 402, + 190 + ], + "spans": [ + { + "bbox": [ + 204, + 177, + 402, + 190 + ], + "type": "text", + "content": "Ran Yi" + }, + { + "bbox": [ + 204, + 177, + 402, + 190 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 204, + 177, + 402, + 190 + ], + "type": "text", + "content": " Lizhuang Ma" + }, + { + "bbox": [ + 204, + 177, + 402, + 190 + ], + "type": "inline_equation", + "content": "^{1\\ddagger}" + }, + { + "bbox": [ + 204, + 177, + 402, + 190 + ], + "type": "text", + "content": " Dong Chen" + }, + { + "bbox": [ + 204, + 177, + 402, + 190 + ], + "type": "inline_equation", + "content": "^{3}" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 135, + 191, + 459, + 206 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 135, + 191, + 459, + 206 + ], + "spans": [ + { + "bbox": [ + 135, + 191, + 459, + 206 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 135, + 191, + 459, + 206 + ], + "type": "text", + "content": "Shanghai Jiao Tong University " + }, + { + "bbox": [ + 135, + 191, + 459, + 206 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 135, + 191, + 459, + 206 + ], + "type": "text", + "content": "HKUST " + }, + { + "bbox": [ + 135, + 191, + 459, + 206 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 135, + 191, + 459, + 206 + ], + "type": "text", + "content": "Microsoft Research" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 190, + 209, + 402, + 222 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 190, + 209, + 402, + 222 + ], + "spans": [ + { + "bbox": [ + 190, + 209, + 402, + 222 + ], + "type": "text", + "content": "https://make-it-3d.github.io/" + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 50, + 228, + 116, + 358 + ], + "blocks": [ + { + "bbox": [ + 50, + 228, + 116, + 358 + ], + "lines": [ + { + "bbox": [ + 50, + 228, + 116, + 358 + ], + "spans": [ + { + "bbox": [ + 50, + 228, + 116, + 358 + ], + "type": "image", + "image_path": "e54bedeb393467444c8b6236dc07517aec8c9ad89da743d7aa84311408eceb5c.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 63, + 360, + 102, + 369 + ], + "lines": [ + { + "bbox": [ + 63, + 360, + 102, + 369 + ], + "spans": [ + { + "bbox": [ + 63, + 360, + 102, + 369 + ], + "type": "text", + "content": "Reference" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 124, + 232, + 168, + 295 + ], + "blocks": [ + { + "bbox": [ + 124, + 232, + 168, + 295 + ], + "lines": [ + { + "bbox": [ + 124, + 232, + 168, + 295 + ], + "spans": [ + { + "bbox": [ + 124, + 232, + 168, + 295 + ], + "type": "image", + "image_path": "d6988a0e37b398c91d743993ae325f8abaf3009b5cd63f6585e4ddaba4694c33.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 116, + 300, + 179, + 358 + ], + "blocks": [ + { + "bbox": [ + 116, + 300, + 179, + 358 + ], + "lines": [ + { + "bbox": [ + 116, + 300, + 179, + 358 + ], + "spans": [ + { + "bbox": [ + 116, + 300, + 179, + 358 + ], + "type": "image", + "image_path": "06d8e89be7e724c061996062c71feb68bbecd45286463d1415674c6c1804fa61.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 136, + 360, + 166, + 369 + ], + "lines": [ + { + "bbox": [ + 136, + 360, + 166, + 369 + ], + "spans": [ + { + "bbox": [ + 136, + 360, + 166, + 369 + ], + "type": "text", + "content": "Normal" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 189, + 232, + 231, + 295 + ], + "blocks": [ + { + "bbox": [ + 189, + 232, + 231, + 295 + ], + "lines": [ + { + "bbox": [ + 189, + 232, + 231, + 295 + ], + "spans": [ + { + "bbox": [ + 189, + 232, + 231, + 295 + ], + "type": "image", + "image_path": "c8ddbe1d4ca6ed848a8c7d2d8f64ec292e21e007c1f295d9ef81a729ad6b266e.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 180, + 300, + 244, + 359 + ], + "blocks": [ + { + "bbox": [ + 180, + 300, + 244, + 359 + ], + "lines": [ + { + "bbox": [ + 180, + 300, + 244, + 359 + ], + "spans": [ + { + "bbox": [ + 180, + 300, + 244, + 359 + ], + "type": "image", + "image_path": "7315f1d333501f5ee13361beca23f10de0377066f33f35bbcefc56c6a42d8850.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 374, + 545, + 399 + ], + "lines": [ + { + "bbox": [ + 46, + 374, + 545, + 399 + ], + "spans": [ + { + "bbox": [ + 46, + 374, + 545, + 399 + ], + "type": "text", + "content": "Figure 1: Make-It-3D can create high-fidelity 3D content from only a single image. We show the normal map and novel-view renderings of created 3D content, showcasing fine geometry and faithful textures with stunning quality at novel views." + } + ] + } + ], + "index": 27, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 251, + 232, + 291, + 295 + ], + "blocks": [ + { + "bbox": [ + 251, + 232, + 291, + 295 + ], + "lines": [ + { + "bbox": [ + 251, + 232, + 291, + 295 + ], + "spans": [ + { + "bbox": [ + 251, + 232, + 291, + 295 + ], + "type": "image", + "image_path": "deee086095831a77801779b79f040b80ab1e5dd32ad409e107ad8a56e47989cb.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 244, + 301, + 306, + 359 + ], + "blocks": [ + { + "bbox": [ + 220, + 360, + 269, + 369 + ], + "lines": [ + { + "bbox": [ + 220, + 360, + 269, + 369 + ], + "spans": [ + { + "bbox": [ + 220, + 360, + 269, + 369 + ], + "type": "text", + "content": "Novel Views" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 244, + 301, + 306, + 359 + ], + "lines": [ + { + "bbox": [ + 244, + 301, + 306, + 359 + ], + "spans": [ + { + "bbox": [ + 244, + 301, + 306, + 359 + ], + "type": "image", + "image_path": "46467de6d7a713ed4f9f698b7fdf55131b9076b7319b701e60af864fa2169988.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 305, + 228, + 372, + 358 + ], + "blocks": [ + { + "bbox": [ + 305, + 228, + 372, + 358 + ], + "lines": [ + { + "bbox": [ + 305, + 228, + 372, + 358 + ], + "spans": [ + { + "bbox": [ + 305, + 228, + 372, + 358 + ], + "type": "image", + "image_path": "c44196c384e8057e4868b8725f5fcc8ed870cb91b7156a49cfb588d89d497ee2.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 321, + 360, + 360, + 369 + ], + "lines": [ + { + "bbox": [ + 321, + 360, + 360, + 369 + ], + "spans": [ + { + "bbox": [ + 321, + 360, + 360, + 369 + ], + "type": "text", + "content": "Reference" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_caption" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 381, + 228, + 416, + 295 + ], + "blocks": [ + { + "bbox": [ + 381, + 228, + 416, + 295 + ], + "lines": [ + { + "bbox": [ + 381, + 228, + 416, + 295 + ], + "spans": [ + { + "bbox": [ + 381, + 228, + 416, + 295 + ], + "type": "image", + "image_path": "b466c4cbe7820bf5365c701cd8f1b6e36bd3fedfa392a00c24a7abb50d45a98c.jpg" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_body" + } + ], + "index": 19 + }, + { + "type": "image", + "bbox": [ + 378, + 295, + 427, + 358 + ], + "blocks": [ + { + "bbox": [ + 378, + 295, + 427, + 358 + ], + "lines": [ + { + "bbox": [ + 378, + 295, + 427, + 358 + ], + "spans": [ + { + "bbox": [ + 378, + 295, + 427, + 358 + ], + "type": "image", + "image_path": "7b449617522578647040ecfede2f1e60e4035daa8dcc27830f52bc386266f428.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 384, + 360, + 414, + 369 + ], + "lines": [ + { + "bbox": [ + 384, + 360, + 414, + 369 + ], + "spans": [ + { + "bbox": [ + 384, + 360, + 414, + 369 + ], + "type": "text", + "content": "Normal" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_caption" + } + ], + "index": 20 + }, + { + "type": "image", + "bbox": [ + 432, + 229, + 465, + 295 + ], + "blocks": [ + { + "bbox": [ + 432, + 229, + 465, + 295 + ], + "lines": [ + { + "bbox": [ + 432, + 229, + 465, + 295 + ], + "spans": [ + { + "bbox": [ + 432, + 229, + 465, + 295 + ], + "type": "image", + "image_path": "1528522dda3176fdd420078451dc2aafc08d8debb7c77d0e3f117de9112d6c53.jpg" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_body" + } + ], + "index": 22 + }, + { + "type": "image", + "bbox": [ + 430, + 295, + 479, + 358 + ], + "blocks": [ + { + "bbox": [ + 430, + 295, + 479, + 358 + ], + "lines": [ + { + "bbox": [ + 430, + 295, + 479, + 358 + ], + "spans": [ + { + "bbox": [ + 430, + 295, + 479, + 358 + ], + "type": "image", + "image_path": "8ea39c7950b4dc4d78171a37214866f44d905eec2216782355e74c31012ec1d8.jpg" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 457, + 360, + 504, + 369 + ], + "lines": [ + { + "bbox": [ + 457, + 360, + 504, + 369 + ], + "spans": [ + { + "bbox": [ + 457, + 360, + 504, + 369 + ], + "type": "text", + "content": "Novel Views" + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_caption" + } + ], + "index": 23 + }, + { + "type": "image", + "bbox": [ + 485, + 228, + 516, + 295 + ], + "blocks": [ + { + "bbox": [ + 485, + 228, + 516, + 295 + ], + "lines": [ + { + "bbox": [ + 485, + 228, + 516, + 295 + ], + "spans": [ + { + "bbox": [ + 485, + 228, + 516, + 295 + ], + "type": "image", + "image_path": "4b4ac5070eafd52ae7825894c666cd449c231a143244024f4b022565aa462d14.jpg" + } + ] + } + ], + "index": 25, + "angle": 0, + "type": "image_body" + } + ], + "index": 25 + }, + { + "type": "image", + "bbox": [ + 480, + 297, + 542, + 358 + ], + "blocks": [ + { + "bbox": [ + 480, + 297, + 542, + 358 + ], + "lines": [ + { + "bbox": [ + 480, + 297, + 542, + 358 + ], + "spans": [ + { + "bbox": [ + 480, + 297, + 542, + 358 + ], + "type": "image", + "image_path": "91113be4f7afec537cc6ef0069c12164fed42fd03dcaeb032e41fa4b02d48104.jpg" + } + ] + } + ], + "index": 26, + "angle": 0, + "type": "image_body" + } + ], + "index": 26 + }, + { + "bbox": [ + 143, + 404, + 192, + 417 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 404, + 192, + 417 + ], + "spans": [ + { + "bbox": [ + 143, + 404, + 192, + 417 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 45, + 422, + 289, + 673 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 422, + 289, + 673 + ], + "spans": [ + { + "bbox": [ + 45, + 422, + 289, + 673 + ], + "type": "text", + "content": "In this work, we investigate the problem of creating high-fidelity 3D content from only a single image. This is inherently challenging: it essentially involves estimating the underlying 3D geometry while simultaneously hallucinating unseen textures. To address this challenge, we leverage prior knowledge from a well-trained 2D diffusion model to act as 3D-aware supervision for 3D creation. Our approach, Make-It-3D, employs a two-stage optimization pipeline: the first stage optimizes a neural radiance field by incorporating constraints from the reference image at the frontal view and diffusion prior at novel views; the second stage transforms the coarse model into textured point clouds and further elevates the realism with diffusion prior while leveraging the high-quality textures from the reference image. Extensive experiments demonstrate that our method outperforms prior works by a large margin, resulting in faithful reconstructions and impressive visual quality. Our method presents the first attempt to achieve high-quality 3D creation from a single image for general objects and enables various applications such as text-to-3D creation and texture editing." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 404, + 386, + 417 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 404, + 386, + 417 + ], + "spans": [ + { + "bbox": [ + 307, + 404, + 386, + 417 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 304, + 426, + 545, + 593 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 426, + 545, + 593 + ], + "spans": [ + { + "bbox": [ + 304, + 426, + 545, + 593 + ], + "type": "text", + "content": "Given a single image as in Figure 1, how would the object portrayed in the image look like from a different perspective? Humans possess an innate ability to effortlessly imagine 3D geometry and hallucinate the appearance of novel views with a glance at the picture based on their prior knowledge about the world. In this work, we aim to achieve a similar goal: creating high-fidelity 3D content from a real or artificially generated single image. This will open up new avenues for artistic expression and creativity, such as bringing 3D effects to the fantasy images given by the cutting-edge 2D generative models like Stable Diffusion [38]. By offering a more accessible and automated way to create visually stunning 3D content, we hope to engage a broader audience with the world of 3D modeling with ease." + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 304, + 594, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 546, + 714 + ], + "type": "text", + "content": "The creation of 3D objects from a single image presents a significant challenge due to the limited information that can be inferred from a single viewpoint. One categories of works aim to produce 3D photo effect [28, 41, 11, 47] in the manner of image-based rendering or single-view 3D reconstruction with neural rendering [54, 56, 37]. However, these methods often struggle with reconstructing fine geometry and fall short of rendering in large views. Another line of research [26, 51, 59, 55] projects the input image into the latent space of the pretrained 3D-aware generative networks." + } + ] + } + ], + "index": 32 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 693, + 250, + 703 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 693, + 250, + 703 + ], + "spans": [ + { + "bbox": [ + 58, + 693, + 250, + 703 + ], + "type": "inline_equation", + "content": "\\dagger" + }, + { + "bbox": [ + 58, + 693, + 250, + 703 + ], + "type": "text", + "content": "Work is done during the internship at Microsoft Research." + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "type": "inline_equation", + "content": "\\ddagger" + }, + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "type": "text", + "content": " Corresponding authors." + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "22819" + } + ] + } + ], + "index": 36 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 167 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 167 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 167 + ], + "type": "text", + "content": "Despite their impressive performance, the existing 3D generative networks mainly model objects from a specific class and are therefore incapable of handling general 3D objects. In our case, we aim for general 3D creation from an arbitrary image, yet constructing a sufficiently large and diverse dataset for estimating the novel views or building a powerful 3D foundation model for general objects remains insurmountable." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 170, + 289, + 315 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 170, + 289, + 315 + ], + "spans": [ + { + "bbox": [ + 46, + 170, + 289, + 315 + ], + "type": "text", + "content": "Unlike the scarcity of 3D models, images are much more readily available, and recent advancements in diffusion models have sparked a revolution in 2D image generation [34, 39, 38, 52, 4]. Interestingly, we observed that well-trained image diffusion models can generate images under various views, which implies that they have already incorporated 3D knowledge. This has motivated us to explore the possibility of cultivating prior knowledge in a 2D diffusion model to reconstruct 3D objects. With diffusion prior, we propose Make-It-3D, a two-stage 3D content creation method that can generate a high-fidelity 3D object with superior quality from only one image." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 316, + 289, + 520 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 316, + 289, + 520 + ], + "spans": [ + { + "bbox": [ + 46, + 316, + 289, + 520 + ], + "type": "text", + "content": "In the first stage, we leverage diffusion prior to optimize a neural radiance field (NeRF) [23] by applying score distillation sampling (SDS) [32], and constrain this optimization with reference-view supervision. Different from prior text-to-3D works [32, 18, 22], we focus on image-based 3D creation so that we need to prioritize the faithfulness to the reference image. However, we observed that while 3D models generated with SDS match text prompts well, they often fail to align faithfully with reference images since textual descriptions do not capture all object details. To address this issue, we go beyond SDS by simultaneously maximizing the image-level similarity between the reference and the novel view rendering denoised by a diffusion model. Also, as images inherently capture more geometry-related information than textual descriptions, we can thus incorporate the depth of the reference image as an extra geometry prior to alleviate the shape ambiguity of NeRF optimization." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 522, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 522, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 522, + 289, + 715 + ], + "type": "text", + "content": "While the first stage generates a coarse model with plausible geometry, its appearance often deviates from the quality of the reference, exhibiting over-smooth textures and saturated colors [32]. This has limited its overall realism, and it is imperative to further bridge the gap between coarse model and reference image. As texture is more critical than geometry for human perception in the context of high-quality rendering, we choose to prioritize texture enhancement in the second stage, while inheriting the geometry from the first stage. We refine the model by leveraging the availability of ground-truth textures for regions that are observable in the reference image. To achieve this, we export the coarse NeRF model to textured point clouds and project reference textures onto their corresponding areas in the point clouds. We then utilize diffusion prior to enhance the texture of the remaining points by jointly optimizing" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 304, + 72, + 545, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 96 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 96 + ], + "type": "text", + "content": "the point feature and a point cloud renderer, resulting in a clearly improved texture of the generated 3D model." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 96, + 547, + 227 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 96, + 547, + 227 + ], + "spans": [ + { + "bbox": [ + 304, + 96, + 547, + 227 + ], + "type": "text", + "content": "With diffusion prior as multi-view supervision, our approach can be applied to general objects without being limited to specific categories. To evaluate the method, we create a benchmark consisting of 400 images including both real images and generated images from 2D diffusion. We evaluate the proposed method on public DTU dataset [1] and our benchmark, and extensive experiments show a clear improvement over previous works. Furthermore, our method enables a range of applications beyond image-to-3D creation such as texture editing and high-quality text-to-3D creation. Our main contributions are summarized as:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 317, + 228, + 545, + 383 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 317, + 228, + 545, + 287 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 228, + 545, + 287 + ], + "spans": [ + { + "bbox": [ + 317, + 228, + 545, + 287 + ], + "type": "text", + "content": "- We propose Make-It-3D, a framework to create a high-fidelity 3D object from a single image, using a 2D diffusion model as 3D-aware prior. It does not require multi-view images for training and can be applied to any input image, whether it is real or generated." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 288, + 545, + 346 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 288, + 545, + 346 + ], + "spans": [ + { + "bbox": [ + 317, + 288, + 545, + 346 + ], + "type": "text", + "content": "- With a two-stage creation scheme, Make-It-3D represents the first work to achieve high-fidelity 3D creation for general objects. The resulting 3D models exhibit detailed geometry and realistic textures that accurately conform to the reference images." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 348, + 545, + 383 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 348, + 545, + 383 + ], + "spans": [ + { + "bbox": [ + 317, + 348, + 545, + 383 + ], + "type": "text", + "content": "- Beyond image-to-3D creation, our method enables multiple applications such as high-quality text-to-3D creation and texture editing." + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 394, + 392, + 407 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 394, + 392, + 407 + ], + "spans": [ + { + "bbox": [ + 306, + 394, + 392, + 407 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 415, + 545, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 415, + 545, + 641 + ], + "spans": [ + { + "bbox": [ + 304, + 415, + 545, + 641 + ], + "type": "text", + "content": "Novel view synthesis from a few images. Early attempts [14, 6, 45, 31] usually require dense observations of a scene from uniformly sampled poses. Recent emergence of implicit representations [42, 23] significantly advances the synthesis quality of novel views, whereas they tend to find a degenerate solution when given only very few input views. To enable novel view from sparse input views, a growing body of works [20, 46, 27] hence turn to extra prior knowledge as additional regularizations. PixelNeRF [59] predicts a continuous neural representation conditioned on the input images rather than only leveraging input views for supervision. DietNeRF [10] penalizes a semantic consistency loss by minimizing distance between CLIP [33] features of different views. With recent rapid progress of diffusion models, 3DiM [53] introduces a pose-conditional diffusion model that generates a novel view conditioned on a source view and a target pose. RenderDiffusion [3] presents a diffusion model for 3D generation that incorporates a triplane rendering mode into the denoiser." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 642, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 547, + 714 + ], + "type": "text", + "content": "Single-image 3D photography. Synthesizing novel views from a single image is quite challenging as it is a highly ill-posed problem, requiring precise geometry estimation and disocclusion of both geometry and texture. Increasing effort has been dedicated to this problem [62, 7, 19, 29, 31, 36, 28, 44], many of which can only handle specific types. Among" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "footer", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "22820" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 72, + 88, + 160, + 175 + ], + "blocks": [ + { + "bbox": [ + 75, + 76, + 138, + 86 + ], + "lines": [ + { + "bbox": [ + 75, + 76, + 138, + 86 + ], + "spans": [ + { + "bbox": [ + 75, + 76, + 138, + 86 + ], + "type": "text", + "content": "1. Coarse Stage" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 72, + 88, + 160, + 175 + ], + "lines": [ + { + "bbox": [ + 72, + 88, + 160, + 175 + ], + "spans": [ + { + "bbox": [ + 72, + 88, + 160, + 175 + ], + "type": "image", + "image_path": "7d774c4c5614db15c5362007b10d97d916661e68ae59ce0811427f18556af359.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 96, + 175, + 136, + 184 + ], + "lines": [ + { + "bbox": [ + 96, + 175, + 136, + 184 + ], + "spans": [ + { + "bbox": [ + 96, + 175, + 136, + 184 + ], + "type": "text", + "content": "Reference" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 178, + 84, + 269, + 170 + ], + "blocks": [ + { + "bbox": [ + 178, + 84, + 269, + 170 + ], + "lines": [ + { + "bbox": [ + 178, + 84, + 269, + 170 + ], + "spans": [ + { + "bbox": [ + 178, + 84, + 269, + 170 + ], + "type": "image", + "image_path": "4593f30bc501fcd83b611a5c949cd88093b26139172d144ed030f4bb4a496634.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 182, + 171, + 270, + 180 + ], + "lines": [ + { + "bbox": [ + 182, + 171, + 270, + 180 + ], + "spans": [ + { + "bbox": [ + 182, + 171, + 270, + 180 + ], + "type": "text", + "content": "Neural Radiance Field" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 278, + 114, + 296, + 125 + ], + "blocks": [ + { + "bbox": [ + 278, + 114, + 296, + 125 + ], + "lines": [ + { + "bbox": [ + 278, + 114, + 296, + 125 + ], + "spans": [ + { + "bbox": [ + 278, + 114, + 296, + 125 + ], + "type": "image", + "image_path": "d8d9f51668e36cb6a078665b44ec8697780ff6c4c010b9ea84f5da4d7e386fb0.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 275, + 150, + 294, + 164 + ], + "blocks": [ + { + "bbox": [ + 275, + 150, + 294, + 164 + ], + "lines": [ + { + "bbox": [ + 275, + 150, + 294, + 164 + ], + "spans": [ + { + "bbox": [ + 275, + 150, + 294, + 164 + ], + "type": "image", + "image_path": "bb8be0325ef351153c5332449b2a77a15c68becfaee3d7a7b9d862a0be6ff756.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 278, + 167, + 294, + 174 + ], + "lines": [ + { + "bbox": [ + 278, + 167, + 294, + 174 + ], + "spans": [ + { + "bbox": [ + 278, + 167, + 294, + 174 + ], + "type": "text", + "content": "Novel" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 299, + 79, + 338, + 126 + ], + "blocks": [ + { + "bbox": [ + 273, + 128, + 299, + 135 + ], + "lines": [ + { + "bbox": [ + 273, + 128, + 299, + 135 + ], + "spans": [ + { + "bbox": [ + 273, + 128, + 299, + 135 + ], + "type": "text", + "content": "Reference" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 299, + 79, + 338, + 126 + ], + "lines": [ + { + "bbox": [ + 299, + 79, + 338, + 126 + ], + "spans": [ + { + "bbox": [ + 299, + 79, + 338, + 126 + ], + "type": "image", + "image_path": "2c38c99e723df4fcfbb294b96af57eedf2b7a181f62f923ada079a2ed5ff1ecd.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 301, + 133, + 342, + 184 + ], + "blocks": [ + { + "bbox": [ + 280, + 135, + 293, + 140 + ], + "lines": [ + { + "bbox": [ + 280, + 135, + 293, + 140 + ], + "spans": [ + { + "bbox": [ + 280, + 135, + 293, + 140 + ], + "type": "text", + "content": "view" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 279, + 175, + 294, + 181 + ], + "lines": [ + { + "bbox": [ + 279, + 175, + 294, + 181 + ], + "spans": [ + { + "bbox": [ + 279, + 175, + 294, + 181 + ], + "type": "text", + "content": "views" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 301, + 133, + 342, + 184 + ], + "lines": [ + { + "bbox": [ + 301, + 133, + 342, + 184 + ], + "spans": [ + { + "bbox": [ + 301, + 133, + 342, + 184 + ], + "type": "image", + "image_path": "d29f64a74478541c3423fc56a17e6a485f568ba8ded840576ea2e279f61a303f.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 201, + 200, + 290, + 220 + ], + "lines": [ + { + "bbox": [ + 201, + 200, + 290, + 220 + ], + "spans": [ + { + "bbox": [ + 201, + 200, + 290, + 220 + ], + "type": "text", + "content": "A brown teddy bear sitting on a ground." + } + ] + } + ], + "index": 27, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 342, + 80, + 380, + 126 + ], + "blocks": [ + { + "bbox": [ + 342, + 80, + 380, + 126 + ], + "lines": [ + { + "bbox": [ + 342, + 80, + 380, + 126 + ], + "spans": [ + { + "bbox": [ + 342, + 80, + 380, + 126 + ], + "type": "image", + "image_path": "823a480f4417fbd883ff5da354595ff480597c601dbb23141667a9e92f715c69.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 381, + 93, + 423, + 103 + ], + "lines": [ + { + "bbox": [ + 381, + 93, + 423, + 103 + ], + "spans": [ + { + "bbox": [ + 381, + 93, + 423, + 103 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{ref}, \\mathcal{L}_{depth}" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 345, + 133, + 385, + 185 + ], + "blocks": [ + { + "bbox": [ + 345, + 133, + 385, + 185 + ], + "lines": [ + { + "bbox": [ + 345, + 133, + 385, + 185 + ], + "spans": [ + { + "bbox": [ + 345, + 133, + 385, + 185 + ], + "type": "image", + "image_path": "b57e40bb396b9b7ceb0c48c3f46ec07eb1505c26b7a1224cf96318c237867545.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 388, + 105, + 413, + 115 + ], + "blocks": [ + { + "bbox": [ + 388, + 105, + 413, + 115 + ], + "lines": [ + { + "bbox": [ + 388, + 105, + 413, + 115 + ], + "spans": [ + { + "bbox": [ + 388, + 105, + 413, + 115 + ], + "type": "image", + "image_path": "05fb9987fe16058162735ea7722eafa54434db1ed553242514b073246989dd1e.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 427, + 77, + 477, + 127 + ], + "blocks": [ + { + "bbox": [ + 427, + 77, + 477, + 127 + ], + "lines": [ + { + "bbox": [ + 427, + 77, + 477, + 127 + ], + "spans": [ + { + "bbox": [ + 427, + 77, + 477, + 127 + ], + "type": "image", + "image_path": "a9c7c4e002951609e3fcf1df9fbe116a7abc06333719a8584cd93622c26fd75a.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 440, + 129, + 466, + 135 + ], + "lines": [ + { + "bbox": [ + 440, + 129, + 466, + 135 + ], + "spans": [ + { + "bbox": [ + 440, + 129, + 466, + 135 + ], + "type": "text", + "content": "Estimated" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 440, + 136, + 460, + 142 + ], + "lines": [ + { + "bbox": [ + 440, + 136, + 460, + 142 + ], + "spans": [ + { + "bbox": [ + 440, + 136, + 460, + 142 + ], + "type": "text", + "content": "Depth" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 482, + 82, + 525, + 129 + ], + "blocks": [ + { + "bbox": [ + 482, + 82, + 525, + 129 + ], + "lines": [ + { + "bbox": [ + 482, + 82, + 525, + 129 + ], + "spans": [ + { + "bbox": [ + 482, + 82, + 525, + 129 + ], + "type": "image", + "image_path": "3c577e15e791eec6d36cd64ea1af85ca419e68fc15fbec4265d02e27bd1f6c2f.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 488, + 129, + 511, + 135 + ], + "lines": [ + { + "bbox": [ + 488, + 129, + 511, + 135 + ], + "spans": [ + { + "bbox": [ + 488, + 129, + 511, + 135 + ], + "type": "text", + "content": "Masked" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 486, + 136, + 512, + 142 + ], + "lines": [ + { + "bbox": [ + 486, + 136, + 512, + 142 + ], + "spans": [ + { + "bbox": [ + 486, + 136, + 512, + 142 + ], + "type": "text", + "content": "Reference" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_caption" + } + ], + "index": 20 + }, + { + "type": "image", + "bbox": [ + 87, + 242, + 138, + 293 + ], + "blocks": [ + { + "bbox": [ + 74, + 231, + 135, + 240 + ], + "lines": [ + { + "bbox": [ + 74, + 231, + 135, + 240 + ], + "spans": [ + { + "bbox": [ + 74, + 231, + 135, + 240 + ], + "type": "text", + "content": "2. Refine Stage" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 87, + 242, + 138, + 293 + ], + "lines": [ + { + "bbox": [ + 87, + 242, + 138, + 293 + ], + "spans": [ + { + "bbox": [ + 87, + 242, + 138, + 293 + ], + "type": "image", + "image_path": "845a25496e250705aeaf72b1d3b2515720a2b6262aa0a7b564225c5045527477.jpg" + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 134, + 202, + 176, + 218 + ], + "lines": [ + { + "bbox": [ + 134, + 202, + 176, + 218 + ], + "spans": [ + { + "bbox": [ + 134, + 202, + 176, + 218 + ], + "type": "text", + "content": "Image Caption Model" + } + ] + } + ], + "index": 26, + "angle": 0, + "type": "image_caption" + } + ], + "index": 24 + }, + { + "type": "image", + "bbox": [ + 88, + 294, + 139, + 344 + ], + "blocks": [ + { + "bbox": [ + 88, + 294, + 139, + 344 + ], + "lines": [ + { + "bbox": [ + 88, + 294, + 139, + 344 + ], + "spans": [ + { + "bbox": [ + 88, + 294, + 139, + 344 + ], + "type": "image", + "image_path": "d4b886cfe4224543edf80ae17a93c703c4d6fe8816392eba84a6b88e6a3420b3.jpg" + } + ] + } + ], + "index": 25, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 356, + 545, + 404 + ], + "lines": [ + { + "bbox": [ + 46, + 356, + 545, + 404 + ], + "spans": [ + { + "bbox": [ + 46, + 356, + 545, + 404 + ], + "type": "text", + "content": "Figure 2: Overview architecture. We propose a two-stage framework for creating a high-quality 3D model from a reference image with diffusion prior (Sec. 3.1). At the coarse stage, we optimize a NeRF for reconstructing the geometry of the reference image (Sec. 3.2). We further build textured point clouds from NeRF and the reference image, and jointly optimize the texture of invisible points and a learnable deferred renderer to generate realistic and view-consistent textures (Sec. 3.3)." + } + ] + } + ], + "index": 43, + "angle": 0, + "type": "image_caption" + } + ], + "index": 25 + }, + { + "type": "image", + "bbox": [ + 199, + 246, + 268, + 329 + ], + "blocks": [ + { + "bbox": [ + 231, + 235, + 269, + 243 + ], + "lines": [ + { + "bbox": [ + 231, + 235, + 269, + 243 + ], + "spans": [ + { + "bbox": [ + 231, + 235, + 269, + 243 + ], + "type": "text", + "content": "Invisible Points" + } + ] + } + ], + "index": 28, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 199, + 246, + 268, + 329 + ], + "lines": [ + { + "bbox": [ + 199, + 246, + 268, + 329 + ], + "spans": [ + { + "bbox": [ + 199, + 246, + 268, + 329 + ], + "type": "image", + "image_path": "2caf905e558ed575170d96a958fe7fd2f966219bed7d7357b5dc26682bde9913.jpg" + } + ] + } + ], + "index": 29, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 276, + 247, + 319, + 253 + ], + "lines": [ + { + "bbox": [ + 276, + 247, + 319, + 253 + ], + "spans": [ + { + "bbox": [ + 276, + 247, + 319, + 253 + ], + "type": "text", + "content": "#" + } + ] + } + ], + "index": 30, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 276, + 254, + 319, + 260 + ], + "lines": [ + { + "bbox": [ + 276, + 254, + 319, + 260 + ], + "spans": [ + { + "bbox": [ + 276, + 254, + 319, + 260 + ], + "type": "text", + "content": "#" + } + ] + } + ], + "index": 31, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 187, + 331, + 276, + 340 + ], + "lines": [ + { + "bbox": [ + 187, + 331, + 276, + 340 + ], + "spans": [ + { + "bbox": [ + 187, + 331, + 276, + 340 + ], + "type": "text", + "content": "Textured Point Clouds" + } + ] + } + ], + "index": 37, + "angle": 0, + "type": "image_caption" + } + ], + "index": 29 + }, + { + "type": "image", + "bbox": [ + 278, + 269, + 286, + 274 + ], + "blocks": [ + { + "bbox": [ + 278, + 262, + 319, + 268 + ], + "lines": [ + { + "bbox": [ + 278, + 262, + 319, + 268 + ], + "spans": [ + { + "bbox": [ + 278, + 262, + 319, + 268 + ], + "type": "text", + "content": "#" + } + ] + } + ], + "index": 32, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 278, + 269, + 286, + 274 + ], + "lines": [ + { + "bbox": [ + 278, + 269, + 286, + 274 + ], + "spans": [ + { + "bbox": [ + 278, + 269, + 286, + 274 + ], + "type": "image", + "image_path": "f6a4055fb428f0e0099ad9a27f22ddd56b49ba8895c347752ce93e838ab6d98a.jpg" + } + ] + } + ], + "index": 33, + "angle": 0, + "type": "image_body" + } + ], + "index": 33 + }, + { + "type": "image", + "bbox": [ + 278, + 275, + 287, + 282 + ], + "blocks": [ + { + "bbox": [ + 278, + 275, + 287, + 282 + ], + "lines": [ + { + "bbox": [ + 278, + 275, + 287, + 282 + ], + "spans": [ + { + "bbox": [ + 278, + 275, + 287, + 282 + ], + "type": "image", + "image_path": "ebd11aedfb73f6f632ced0e7d7e00415ea6fb13d7f5e433b8b68e24578864de9.jpg" + } + ] + } + ], + "index": 34, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 278, + 285, + 287, + 290 + ], + "lines": [ + { + "bbox": [ + 278, + 285, + 287, + 290 + ], + "spans": [ + { + "bbox": [ + 278, + 285, + 287, + 290 + ], + "type": "text", + "content": "XX" + } + ] + } + ], + "index": 35, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 290, + 285, + 320, + 291 + ], + "lines": [ + { + "bbox": [ + 290, + 285, + 320, + 291 + ], + "spans": [ + { + "bbox": [ + 290, + 285, + 320, + 291 + ], + "type": "text", + "content": "Descriptors" + } + ] + } + ], + "index": 36, + "angle": 0, + "type": "image_caption" + } + ], + "index": 34 + }, + { + "type": "image", + "bbox": [ + 352, + 240, + 432, + 343 + ], + "blocks": [ + { + "bbox": [ + 332, + 240, + 343, + 338 + ], + "lines": [ + { + "bbox": [ + 332, + 240, + 343, + 338 + ], + "spans": [ + { + "bbox": [ + 332, + 240, + 343, + 338 + ], + "type": "text", + "content": "Z-buffer & Rasterization" + } + ] + } + ], + "index": 38, + "angle": 270, + "type": "image_caption" + }, + { + "bbox": [ + 352, + 240, + 432, + 343 + ], + "lines": [ + { + "bbox": [ + 352, + 240, + 432, + 343 + ], + "spans": [ + { + "bbox": [ + 352, + 240, + 432, + 343 + ], + "type": "image", + "image_path": "1f924942d4ec7baea6a12190aa438f2b4563f4ae640fddceb162d6df64f89704.jpg" + } + ] + } + ], + "index": 39, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 374, + 342, + 423, + 348 + ], + "lines": [ + { + "bbox": [ + 374, + 342, + 423, + 348 + ], + "spans": [ + { + "bbox": [ + 374, + 342, + 423, + 348 + ], + "type": "text", + "content": "Deferred Renderer" + } + ] + } + ], + "index": 40, + "angle": 0, + "type": "image_caption" + } + ], + "index": 39 + }, + { + "type": "image", + "bbox": [ + 434, + 234, + 520, + 338 + ], + "blocks": [ + { + "bbox": [ + 434, + 234, + 520, + 338 + ], + "lines": [ + { + "bbox": [ + 434, + 234, + 520, + 338 + ], + "spans": [ + { + "bbox": [ + 434, + 234, + 520, + 338 + ], + "type": "image", + "image_path": "94ea0028c0a1a7f7a0422a876bac7a8002d8c38d97f7271bc6c368aa0a088ba8.jpg" + } + ] + } + ], + "index": 41, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 443, + 338, + 512, + 347 + ], + "lines": [ + { + "bbox": [ + 443, + 338, + 512, + 347 + ], + "spans": [ + { + "bbox": [ + 443, + 338, + 512, + 347 + ], + "type": "text", + "content": "Enhanced Output" + } + ] + } + ], + "index": 42, + "angle": 0, + "type": "image_caption" + } + ], + "index": 41 + }, + { + "bbox": [ + 46, + 417, + 287, + 537 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 417, + 287, + 537 + ], + "spans": [ + { + "bbox": [ + 46, + 417, + 287, + 537 + ], + "type": "text", + "content": "them, a number of methods rely on layered representations such as layered depth images [40, 48, 41] and multi-plane images (MPIs) [43, 47, 17, 8]. For example, [47] predicts MPIs for view synthesis from single image without requiring ground truth 3D. [41] generates a 3D photo from a given RGB-D input through layered depth image with inpainted color and depth. Yet such a solution is limited by the number of planes and sensitive to discontinuities. Subsequent efforts generalize MPIs to continuous 3D representations such as NeRF [15] and latent 3D point cloud [54]." + } + ] + } + ], + "index": 44 + }, + { + "bbox": [ + 46, + 545, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 545, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 545, + 288, + 713 + ], + "type": "text", + "content": "Lift 2D pretrained model to 3D. With the emergence of recent advances in modeling natural image manifold, how to exploit such powerful 2D pretrained model to recover 3D object structure has received considerable research interest. [30] attempts to reconstruct the 3D shape using pretrained 2D GANs. Subsequently, some works [9, 13, 24] explore zero-shot text-guided 3D content creation utilizing the guidance from CLIP [33]. Recent efforts such as DreamFusion [32], Magic3D [18] and Score Jacobian Chaining [50] explore text-to-3D generation by exploiting a score distillation sampling (SDS) loss derived from a 2D text-to-image diffusion model instead, showing impressive results. LatentNeRF [22] proposes to use a shape prior to guide and assist the 3D generation directly in the latent space" + } + ] + } + ], + "index": 45 + }, + { + "bbox": [ + 304, + 417, + 545, + 502 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 417, + 545, + 502 + ], + "spans": [ + { + "bbox": [ + 304, + 417, + 545, + 502 + ], + "type": "text", + "content": "of the diffusion model. Prior works NeuralLift-360 [57] and NeRDi [5] also leverage the generative prior for 3D reconstruction from a single view. Yet the reconstructed 3D model has limited quality and is poorly aligned with the input image. In contrast, we propose a two-stage 3D synthesis framework with a relaxed SDS loss, yielding high-quality 3D representation faithful to the given input image." + } + ] + } + ], + "index": 46 + }, + { + "bbox": [ + 306, + 513, + 361, + 525 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 513, + 361, + 525 + ], + "spans": [ + { + "bbox": [ + 306, + 513, + 361, + 525 + ], + "type": "text", + "content": "3. Method" + } + ] + } + ], + "index": 47 + }, + { + "bbox": [ + 304, + 534, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 534, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 534, + 545, + 713 + ], + "type": "text", + "content": "Generating novel views for general scenes or objects from only a single image is inherently challenging due to the difficulty of inferring both geometry and missing texture. We therefore tackle this challenge by cultivating the dark knowledge of pretrained 2D diffusion models. Specifically, given an input image " + }, + { + "bbox": [ + 304, + 534, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\pmb{x}" + }, + { + "bbox": [ + 304, + 534, + 545, + 713 + ], + "type": "text", + "content": ", we first hallucinate its underlying 3D representation, neural radiance field (NeRF), whose rendering appears as a plausible sample to a pretrained denoising diffusion model, and we constrain this optimization process with the texture and depth supervision at the reference view. To further improve the rendering realism, we keep the learned geometry and enhance the textures with the reference image. As such, in the second stage, we lift the input image to textured point clouds and focus on refining the color of the points occluded in the reference view." + } + ] + } + ], + "index": 48 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "22821" + } + ] + } + ], + "index": 49 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "content": "We leverage prior knowledge of the text-to-image generative model and the text-image contrastive model for both stages. In this way, we achieve a faithful 3D representation of the input image with restored high-fidelity texture and geometry. The proposed two-stage 3D learning framework is illustrated in Figure 2. We will subsequently brief the preliminaries and then detail our method." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 163, + 134, + 175 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 163, + 134, + 175 + ], + "spans": [ + { + "bbox": [ + 47, + 163, + 134, + 175 + ], + "type": "text", + "content": "3.1. Preliminaries" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 182, + 287, + 300 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 182, + 287, + 300 + ], + "spans": [ + { + "bbox": [ + 46, + 182, + 287, + 300 + ], + "type": "text", + "content": "Recent findings show that pretrained 2D generative models offer rich 3D geometry knowledge for their 2D generation samples. Notably, DreamFusion [32] uses a text-to-image diffusion model to guide the optimization of the 3D representation. Let " + }, + { + "bbox": [ + 46, + 182, + 287, + 300 + ], + "type": "inline_equation", + "content": "\\mathcal{G}_{\\theta}(\\beta)" + }, + { + "bbox": [ + 46, + 182, + 287, + 300 + ], + "type": "text", + "content": " be the rendered image at the given viewpoint " + }, + { + "bbox": [ + 46, + 182, + 287, + 300 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 46, + 182, + 287, + 300 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 182, + 287, + 300 + ], + "type": "inline_equation", + "content": "\\mathcal{G}" + }, + { + "bbox": [ + 46, + 182, + 287, + 300 + ], + "type": "text", + "content": " is the differentiable rendering function for the 3D representation parameterized by " + }, + { + "bbox": [ + 46, + 182, + 287, + 300 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 182, + 287, + 300 + ], + "type": "text", + "content": " and is amenable to choice. DreamFusion optimizes the neural radiance field such that its multi-view renderings look like high-quality samples from a frozen diffusion model." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "spans": [ + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": "Specifically, a diffusion model " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\epsilon_{\\phi}" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": " introduces a random amount of noise " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": " to the rendered image " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\pmb{x}_0 \\coloneqq \\mathcal{G}_{\\theta}(\\beta)" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": " at different timestep " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": ", i.e., " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\pmb{x}_t = \\alpha_t \\pmb{x}_0 + \\sigma_t \\pmb{\\epsilon}" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\epsilon \\sim \\mathcal{N}(\\mathbf{0}, \\mathbf{I})" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": "; " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\alpha_t" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\sigma_t" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": " define a noise schedule whose log signal-to-noise ratio " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\lambda_t = \\log[\\alpha_t^2 / \\sigma_t^2]" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": " linearly decreases with the timestep " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": ". A pretrained text-conditioned diffusion model is trained to reverse this noising process given the text embedding " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\pmb{y}" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": ". To optimize the 3D representation parameters to render images as close as good generation samples, a score distillation sampling (SDS) loss " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{SDS}}" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": " is introduced to push rendered images toward higher density region conditioned on the text embedding. Specifically, " + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{SDS}}" + }, + { + "bbox": [ + 46, + 301, + 289, + 469 + ], + "type": "text", + "content": " computes the difference of predicted noise and the added noise as per-pixel gradient which is used to update the scene parameters, i.e.," + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 475, + 287, + 504 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 475, + 287, + 504 + ], + "spans": [ + { + "bbox": [ + 53, + 475, + 287, + 504 + ], + "type": "interline_equation", + "content": "\\nabla_ {\\theta} \\mathcal {L} _ {\\mathrm {S D S}} (\\phi , \\mathcal {G} _ {\\theta}) = \\mathbb {E} _ {t, \\epsilon} \\left[ w (t) \\left(\\epsilon_ {\\phi} \\left(\\boldsymbol {x} _ {t}; \\boldsymbol {y}, t\\right) - \\epsilon\\right) \\frac {\\partial \\boldsymbol {x}}{\\partial \\theta} \\right], \\tag {1}", + "image_path": "a308dd9387345ff11ada2fdf904636eb452837a14daa60fd75cbb86860d9eea4.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 510, + 287, + 629 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 510, + 287, + 629 + ], + "spans": [ + { + "bbox": [ + 46, + 510, + 287, + 629 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 510, + 287, + 629 + ], + "type": "inline_equation", + "content": "w(t)" + }, + { + "bbox": [ + 46, + 510, + 287, + 629 + ], + "type": "text", + "content": " is a weight function of different noise levels. It can be proved that this loss essentially measures the similarity between the image and the text prompt. The diffusion model acts as a critic and the gradient of " + }, + { + "bbox": [ + 46, + 510, + 287, + 629 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{SDS}}" + }, + { + "bbox": [ + 46, + 510, + 287, + 629 + ], + "type": "text", + "content": " will not be back-propagated through the diffusion network, resulting in efficient computation. As training proceeds, the NeRF parameters are updated during which the 3D object gradually reveals its texture and geometry. In practice, it is found that using a diffusion model with a strong classifier-free guidance leads to higher-quality 3D samples." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "type": "text", + "content": "While DreamFusion uses the Imagen [39] to reverse the noising process at the pixel level, we use the publicly available Stable Diffusion [38] that models the latent space of the VQ-VAE [49] with an encoder " + }, + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathcal{E}" + }, + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "type": "text", + "content": " and a decoder " + }, + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "type": "text", + "content": ". Hence, the used diffusion model digests the latent " + }, + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "type": "inline_equation", + "content": "z_0 \\coloneqq \\mathcal{E}(\\mathcal{G}_{\\theta}(\\beta))" + }, + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "type": "text", + "content": " and the reconstructed latent " + }, + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\hat{z}_0" + }, + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "type": "text", + "content": " can be mapped to image space through " + }, + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\hat{\\boldsymbol{x}} = \\mathcal{D}(\\hat{z}_0)" + }, + { + "bbox": [ + 46, + 630, + 288, + 714 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 306, + 70, + 545, + 147 + ], + "blocks": [ + { + "bbox": [ + 306, + 70, + 545, + 147 + ], + "lines": [ + { + "bbox": [ + 306, + 70, + 545, + 147 + ], + "spans": [ + { + "bbox": [ + 306, + 70, + 545, + 147 + ], + "type": "image", + "image_path": "fbf2adf1b329cc31af3ac5e4dce2323c42cbb509632637866c1b95eea0f08402.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 150, + 547, + 198 + ], + "lines": [ + { + "bbox": [ + 304, + 150, + 547, + 198 + ], + "spans": [ + { + "bbox": [ + 304, + 150, + 547, + 198 + ], + "type": "text", + "content": "Figure 3: Analysis on the coarse stage. Baseline is a naive solution using only " + }, + { + "bbox": [ + 304, + 150, + 547, + 198 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{SDS}}" + }, + { + "bbox": [ + 304, + 150, + 547, + 198 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 150, + 547, + 198 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{ref}}" + }, + { + "bbox": [ + 304, + 150, + 547, + 198 + ], + "type": "text", + "content": ", and it does not match the reference well. With " + }, + { + "bbox": [ + 304, + 150, + 547, + 198 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{CLIP-D}}" + }, + { + "bbox": [ + 304, + 150, + 547, + 198 + ], + "type": "text", + "content": ", the result aligns better with the reference. The depth prior further improves faithfulness." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 217, + 541, + 230 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 217, + 541, + 230 + ], + "spans": [ + { + "bbox": [ + 305, + 217, + 541, + 230 + ], + "type": "text", + "content": "3.2. Coarse Stage: Single-view 3D Reconstruction" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 236, + 545, + 390 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 236, + 545, + 390 + ], + "spans": [ + { + "bbox": [ + 304, + 236, + 545, + 390 + ], + "type": "text", + "content": "As the first stage, we reconstruct a coarse NeRF from the single reference image " + }, + { + "bbox": [ + 304, + 236, + 545, + 390 + ], + "type": "inline_equation", + "content": "\\pmb{x}" + }, + { + "bbox": [ + 304, + 236, + 545, + 390 + ], + "type": "text", + "content": " with the diffusion prior constraining the novel views. Our optimization is expected to meet the following requirements simultaneously: 1) the optimized 3D representation should closely resemble the rendering appearance of the input observation " + }, + { + "bbox": [ + 304, + 236, + 545, + 390 + ], + "type": "inline_equation", + "content": "\\pmb{x}" + }, + { + "bbox": [ + 304, + 236, + 545, + 390 + ], + "type": "text", + "content": " at the reference view; 2) the novel view renderings should demonstrate consistent semantics with the input and appear as plausible as possible; 3) the generated 3D model should exhibit compelling geometry. In view of these, we randomly sample the camera poses around the reference view and enforce constraints upon the rendered images " + }, + { + "bbox": [ + 304, + 236, + 545, + 390 + ], + "type": "inline_equation", + "content": "\\mathcal{G}_{\\theta}" + }, + { + "bbox": [ + 304, + 236, + 545, + 390 + ], + "type": "text", + "content": " for both the reference view and unseen views." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 392, + 545, + 439 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 392, + 545, + 439 + ], + "spans": [ + { + "bbox": [ + 304, + 392, + 545, + 439 + ], + "type": "text", + "content": "Reference view per-pixel loss. To encourage consistent appearance with the input image, we penalize the pixel-wise difference between the rendering and the input image at the reference view " + }, + { + "bbox": [ + 304, + 392, + 545, + 439 + ], + "type": "inline_equation", + "content": "\\beta_{\\mathrm{ref}}" + }, + { + "bbox": [ + 304, + 392, + 545, + 439 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 364, + 446, + 545, + 460 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 364, + 446, + 545, + 460 + ], + "spans": [ + { + "bbox": [ + 364, + 446, + 545, + 460 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {r e f}} = \\left\\| \\boldsymbol {x} \\odot \\boldsymbol {m} - \\mathcal {G} _ {\\theta} \\left(\\beta_ {\\text {r e f}}\\right) \\right\\| _ {1}. \\tag {2}", + "image_path": "9b91599ba4126a9746b09bce62e025ae2e58a36adf6f2d9285ff300ed546c2b7.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 467, + 545, + 503 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 467, + 545, + 503 + ], + "spans": [ + { + "bbox": [ + 304, + 467, + 545, + 503 + ], + "type": "text", + "content": "Here we apply the foreground matting mask " + }, + { + "bbox": [ + 304, + 467, + 545, + 503 + ], + "type": "inline_equation", + "content": "\\pmb{m}" + }, + { + "bbox": [ + 304, + 467, + 545, + 503 + ], + "type": "text", + "content": " to segment out the foreground as we empirically find that this eases the geometry reconstruction, which conforms to [58]." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 503, + 545, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 503, + 545, + 647 + ], + "spans": [ + { + "bbox": [ + 304, + 503, + 545, + 647 + ], + "type": "text", + "content": "Diffusion prior. Optimizing with the aforementioned losses can be unstable and may lead to implausible results, due to the ill-posed nature of the problem. In order to encourage semantically plausible results, additional constraints are needed on the novel view rendering. To tackle this challenge, we resort to the diffusion prior. Prior works on text-to-3D [32, 18] applied " + }, + { + "bbox": [ + 304, + 503, + 545, + 647 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{SDS}}" + }, + { + "bbox": [ + 304, + 503, + 545, + 647 + ], + "type": "text", + "content": " to leverage text-conditioned diffusion models as 3D-aware prior. To utilize " + }, + { + "bbox": [ + 304, + 503, + 545, + 647 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{SDS}}" + }, + { + "bbox": [ + 304, + 503, + 545, + 647 + ], + "type": "text", + "content": " in our case, we use an image captioning model [16], to generate a detailed text description " + }, + { + "bbox": [ + 304, + 503, + 545, + 647 + ], + "type": "inline_equation", + "content": "y" + }, + { + "bbox": [ + 304, + 503, + 545, + 647 + ], + "type": "text", + "content": " for the reference image. With the text prompt " + }, + { + "bbox": [ + 304, + 503, + 545, + 647 + ], + "type": "inline_equation", + "content": "y" + }, + { + "bbox": [ + 304, + 503, + 545, + 647 + ], + "type": "text", + "content": ", we can perform the SDS on the latent space of Stable Diffusion," + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 310, + 653, + 545, + 689 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 653, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 310, + 653, + 545, + 689 + ], + "type": "interline_equation", + "content": "\\nabla_ {\\theta} \\mathcal {L} _ {\\mathrm {S D S}} (\\phi , \\mathcal {G} _ {\\theta}) = \\mathbb {E} _ {t, \\epsilon} \\left[ w (t) \\left(\\epsilon_ {\\phi} \\left(\\boldsymbol {z} _ {t}; \\boldsymbol {y}, t\\right) - \\epsilon\\right) \\frac {\\partial \\boldsymbol {z}}{\\partial \\boldsymbol {x}} \\frac {\\partial \\boldsymbol {x}}{\\partial \\theta} \\right], \\tag {3}", + "image_path": "98256a8122e14f21479d7e0e459dcec564045f777f6cebc09ed8d11c8dbddc00.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 689, + 545, + 713 + ], + "type": "text", + "content": "where the noisy latent " + }, + { + "bbox": [ + 304, + 689, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_t" + }, + { + "bbox": [ + 304, + 689, + 545, + 713 + ], + "type": "text", + "content": " is obtained from a novel view rendering " + }, + { + "bbox": [ + 304, + 689, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 304, + 689, + 545, + 713 + ], + "type": "text", + "content": " by Stable Diffusion encoder." + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "footer", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "22822" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 70, + 95, + 169 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 95, + 169 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 95, + 169 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 95, + 169 + ], + "type": "image", + "image_path": "26f77c84ab863be0135e9b89c18a1d55a9552c2754e805f517d3606f57f445ca.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 56, + 174, + 277, + 186 + ], + "lines": [ + { + "bbox": [ + 56, + 174, + 277, + 186 + ], + "spans": [ + { + "bbox": [ + 56, + 174, + 277, + 186 + ], + "type": "text", + "content": "Figure 4: " + }, + { + "bbox": [ + 56, + 174, + 277, + 186 + ], + "type": "inline_equation", + "content": "360^{\\circ}" + }, + { + "bbox": [ + 56, + 174, + 277, + 186 + ], + "type": "text", + "content": " object reconstruction from real images." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 101, + 70, + 138, + 169 + ], + "blocks": [ + { + "bbox": [ + 101, + 70, + 138, + 169 + ], + "lines": [ + { + "bbox": [ + 101, + 70, + 138, + 169 + ], + "spans": [ + { + "bbox": [ + 101, + 70, + 138, + 169 + ], + "type": "image", + "image_path": "dbf70d1db83d4527533f4ccd8f62d019ffeecaa77d68edad489c0fd85ffdff66.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 145, + 85, + 184, + 168 + ], + "blocks": [ + { + "bbox": [ + 145, + 85, + 184, + 168 + ], + "lines": [ + { + "bbox": [ + 145, + 85, + 184, + 168 + ], + "spans": [ + { + "bbox": [ + 145, + 85, + 184, + 168 + ], + "type": "image", + "image_path": "a4cb6bc2e0b8f21893de5df3776fd5a67672e9957df9c4d06fba5f0f66bfb677.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 186, + 70, + 236, + 168 + ], + "blocks": [ + { + "bbox": [ + 186, + 70, + 236, + 168 + ], + "lines": [ + { + "bbox": [ + 186, + 70, + 236, + 168 + ], + "spans": [ + { + "bbox": [ + 186, + 70, + 236, + 168 + ], + "type": "image", + "image_path": "3b180ad83095ad02186250d25a705636024d2d71ba80b6f486f321f0d2b77f74.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 240, + 84, + 286, + 167 + ], + "blocks": [ + { + "bbox": [ + 240, + 84, + 286, + 167 + ], + "lines": [ + { + "bbox": [ + 240, + 84, + 286, + 167 + ], + "spans": [ + { + "bbox": [ + 240, + 84, + 286, + 167 + ], + "type": "image", + "image_path": "55e8c7f061168dbb1898b9fa4577ac3c7dee7584dbb9567a295a411fea9fb6a7.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 205, + 287, + 301 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 205, + 287, + 301 + ], + "spans": [ + { + "bbox": [ + 46, + 205, + 287, + 301 + ], + "type": "text", + "content": "However, as discussed before, " + }, + { + "bbox": [ + 46, + 205, + 287, + 301 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{SDS}}" + }, + { + "bbox": [ + 46, + 205, + 287, + 301 + ], + "type": "text", + "content": " essentially measures the similarity between the image and the given text prompt. While " + }, + { + "bbox": [ + 46, + 205, + 287, + 301 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{SDS}}" + }, + { + "bbox": [ + 46, + 205, + 287, + 301 + ], + "type": "text", + "content": " can generate 3D models that are faithful to the text prompt, they do not align perfectly with the reference image (see baseline in Figure 3), since text prompts cannot capture all object details. We go beyond this by a diffusion CLIP loss, denoted as " + }, + { + "bbox": [ + 46, + 205, + 287, + 301 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{CLIP-D}}" + }, + { + "bbox": [ + 46, + 205, + 287, + 301 + ], + "type": "text", + "content": ", that additionally enforces the generated model to match the reference image:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 56, + 307, + 287, + 321 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 307, + 287, + 321 + ], + "spans": [ + { + "bbox": [ + 56, + 307, + 287, + 321 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {C L I P - D}} (\\mathcal {X}, \\mathcal {G} _ {\\theta} (\\beta)) = - \\mathcal {E} _ {\\mathrm {C L I P}} (\\mathcal {X}) \\cdot \\mathcal {E} _ {\\mathrm {C L I P}} (\\hat {\\mathcal {X}} _ {0} (\\beta , t)), \\tag {4}", + "image_path": "26f8b23fef727e24691fdb8d40033f054e75b16ca7ddf999c51fb1bc400987fd.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "spans": [ + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "type": "inline_equation", + "content": "\\mathcal{E}_{\\mathrm{CLIP}}(\\cdot)" + }, + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "type": "text", + "content": " is a CLIP image encoder [33]. Rather than directly measuring CLIP loss on the rendered images " + }, + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "type": "inline_equation", + "content": "\\mathcal{G}_{\\theta}(\\beta)" + }, + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "type": "text", + "content": ", we encode the novel view rendering " + }, + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "type": "inline_equation", + "content": "\\mathcal{G}_{\\theta}(\\beta)" + }, + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "type": "text", + "content": " to noisy latent " + }, + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "type": "inline_equation", + "content": "z_{t}" + }, + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "type": "text", + "content": " and then denoise it to a clean image " + }, + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "type": "inline_equation", + "content": "\\tilde{\\mathcal{X}}_0(\\beta, t)" + }, + { + "bbox": [ + 46, + 326, + 287, + 421 + ], + "type": "text", + "content": " with 2D diffusion. By imposing the similarity loss on denoised images sampled from diffusion models, we encourage the rendering to align with the reference image, while resembling high-quality samples from a frozen diffusion." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "spans": [ + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "text", + "content": "In detail, we do not optimize " + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{CLIP - D}}" + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{SDS}}" + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "text", + "content": " at the same time. We use " + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{CLIP - D}}" + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "text", + "content": " at small timesteps and switch to " + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{SDS}}" + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "text", + "content": " at large timesteps. More details and analysis are in the Supplement. Combining " + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{SDS}}" + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{CLIP - D}}" + }, + { + "bbox": [ + 46, + 422, + 287, + 505 + ], + "type": "text", + "content": ", our diffusion prior ensures that the resulting 3D model appears visually appealing and plausible while also conforming to the given image (see Figure 3)." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 506, + 287, + 685 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 506, + 287, + 685 + ], + "spans": [ + { + "bbox": [ + 46, + 506, + 287, + 685 + ], + "type": "text", + "content": "Depth prior. Nonetheless, even if the rendered image appears meaningful to the diffusion model, there still exists shape ambiguity that brings about issues such as sunken faces, over-flat geometry [32] or depth ambiguity (see Figure 3). We mitigate these by leveraging depth prior learned from abundant external images and directly enforcing the supervision in 3D. To be specific, we utilize an off-the-shelf single-view depth estimator [35] to estimate the depth " + }, + { + "bbox": [ + 46, + 506, + 287, + 685 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 506, + 287, + 685 + ], + "type": "text", + "content": " for the input image. While the estimated depth may not accurately characterize the geometric detail, it suffices to ensure plausible geometry and resolve most of the ambiguity. To account for the inaccuracy and the scale mismatch in " + }, + { + "bbox": [ + 46, + 506, + 287, + 685 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 506, + 287, + 685 + ], + "type": "text", + "content": ", akin to [5], we regularize the negative Pearson correlation between the estimated depth and the depth " + }, + { + "bbox": [ + 46, + 506, + 287, + 685 + ], + "type": "inline_equation", + "content": "d(\\beta_{\\mathrm{ref}})" + }, + { + "bbox": [ + 46, + 506, + 287, + 685 + ], + "type": "text", + "content": " modeled by NeRF at the reference viewpoint, i.e.," + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 102, + 689, + 287, + 717 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 102, + 689, + 287, + 717 + ], + "spans": [ + { + "bbox": [ + 102, + 689, + 287, + 717 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {d e p t h}} = - \\frac {\\operatorname {C o v} \\left(d \\left(\\beta_ {\\text {r e f}}\\right) , d\\right)}{\\operatorname {V a r} \\left(d \\left(\\beta_ {\\text {r e f}}\\right)\\right) \\operatorname {V a r} (d)}, \\tag {5}", + "image_path": "f32013a09ab73874fe48b0c5e77a725321139e622d6d9dd4a65c569cf78fd30b.jpg" + } + ] + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 307, + 70, + 545, + 190 + ], + "blocks": [ + { + "bbox": [ + 307, + 70, + 545, + 190 + ], + "lines": [ + { + "bbox": [ + 307, + 70, + 545, + 190 + ], + "spans": [ + { + "bbox": [ + 307, + 70, + 545, + 190 + ], + "type": "image", + "image_path": "ab569120f2bab3c1c7de48391a26dbab8ddb9afb5a180b49b6c85f922573e99c.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 195, + 545, + 232 + ], + "lines": [ + { + "bbox": [ + 304, + 195, + 545, + 232 + ], + "spans": [ + { + "bbox": [ + 304, + 195, + 545, + 232 + ], + "type": "text", + "content": "Figure 5: Illustration of textured point cloud building. We aim at building dense points and texturing visible points using reference image, and invisible points from NeRF." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 243, + 545, + 292 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 243, + 545, + 292 + ], + "spans": [ + { + "bbox": [ + 304, + 243, + 545, + 292 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 243, + 545, + 292 + ], + "type": "inline_equation", + "content": "\\mathrm{Cov}(\\cdot)" + }, + { + "bbox": [ + 304, + 243, + 545, + 292 + ], + "type": "text", + "content": " denotes the covariance, " + }, + { + "bbox": [ + 304, + 243, + 545, + 292 + ], + "type": "inline_equation", + "content": "\\mathrm{Var}(\\cdot)" + }, + { + "bbox": [ + 304, + 243, + 545, + 292 + ], + "type": "text", + "content": " computes the standard deviation. With this regularization, the NeRF depth estimation is encouraged to be linearly correlated with the depth prior." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "spans": [ + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "type": "text", + "content": "Overall training. The overall loss can be formulated as a combination of " + }, + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{ref}}" + }, + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{SDS}}" + }, + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{CLIP-D}}" + }, + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{depth}}" + }, + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "type": "text", + "content": ". To stabilize the optimization process, we adopt a progressive training strategy, where we start with a narrow range of views near the reference view and gradually expand the range during training. With progressive training, we can achieve a " + }, + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "type": "inline_equation", + "content": "360^{\\circ}" + }, + { + "bbox": [ + 304, + 292, + 545, + 376 + ], + "type": "text", + "content": " reconstruction of an object, as shown in Figure 4." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 384, + 533, + 396 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 384, + 533, + 396 + ], + "spans": [ + { + "bbox": [ + 306, + 384, + 533, + 396 + ], + "type": "text", + "content": "3.3. Refine Stage: Neural Texture Enhancement" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 402, + 545, + 485 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 402, + 545, + 485 + ], + "spans": [ + { + "bbox": [ + 304, + 402, + 545, + 485 + ], + "type": "text", + "content": "After the coarse stage, we obtained a 3D model with plausible geometry, but it often displays coarse textures that can bottleneck the overall quality in Figure 6. Further refinement is thus desired for high-fidelity 3D models. Given that humans are more discerning when it comes to texture quality than geometry, we prioritize texture enhancement while preserving the geometry of the coarse model." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 487, + 545, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 487, + 545, + 568 + ], + "spans": [ + { + "bbox": [ + 304, + 487, + 545, + 568 + ], + "type": "text", + "content": "Our key insight for texture enhancement is that for a novel view, certain pixels can be observable in both the novel and reference views. Consequently, we can exploit this overlap to project the high-quality texture of the reference image onto the corresponding areas of the 3D representation. We then focus on enhancing the textures of regions that are occluded in the reference view." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 570, + 545, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 545, + 653 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 545, + 653 + ], + "type": "text", + "content": "While NeRF is a suitable representation in the coarse stage as it can handle topological changes continuously, projecting the reference image onto it is challenging. We thus opt to export the neural radiance field to an explicit representation, specifically point clouds. Compared to the noisy mesh exported by marching cube, point clouds offer a cleaner and more straightforward projection." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": "Textured point cloud building. A naive attempt to build point clouds is to render multi-view RGBD images from NeRF and lift them to textured points in 3D space. However, we found this simple method leads to noisy point clouds due to the conflict among different views: a 3D point" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 741 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 741 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 741 + ], + "type": "text", + "content": "22823" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 69, + 105, + 189 + ], + "blocks": [ + { + "bbox": [ + 50, + 69, + 105, + 189 + ], + "lines": [ + { + "bbox": [ + 50, + 69, + 105, + 189 + ], + "spans": [ + { + "bbox": [ + 50, + 69, + 105, + 189 + ], + "type": "image", + "image_path": "23e1283002c06d3509ca3c7e501a61071643f0fd5d1f7ac298add0ea93177e9c.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 193, + 287, + 240 + ], + "lines": [ + { + "bbox": [ + 46, + 193, + 287, + 240 + ], + "spans": [ + { + "bbox": [ + 46, + 193, + 287, + 240 + ], + "type": "text", + "content": "Figure 6: Visualization of neural texture enhancement. We project the reference textures to the coarse model and enhance the remaining regions to high-frequency details consistent with the reference. Best viewed with zoom-in." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 108, + 70, + 146, + 188 + ], + "blocks": [ + { + "bbox": [ + 108, + 70, + 146, + 188 + ], + "lines": [ + { + "bbox": [ + 108, + 70, + 146, + 188 + ], + "spans": [ + { + "bbox": [ + 108, + 70, + 146, + 188 + ], + "type": "image", + "image_path": "0064eb298ac99a1797db5c3614d9cdfc828af6475530710b86a1b8e0a1c620c5.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 152, + 70, + 192, + 189 + ], + "blocks": [ + { + "bbox": [ + 152, + 70, + 192, + 189 + ], + "lines": [ + { + "bbox": [ + 152, + 70, + 192, + 189 + ], + "spans": [ + { + "bbox": [ + 152, + 70, + 192, + 189 + ], + "type": "image", + "image_path": "28c8e40a82f7dbb0a1fd180b1141b4b8d51a058b4e9ea7966e11f52eee04055f.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 194, + 70, + 238, + 189 + ], + "blocks": [ + { + "bbox": [ + 194, + 70, + 238, + 189 + ], + "lines": [ + { + "bbox": [ + 194, + 70, + 238, + 189 + ], + "spans": [ + { + "bbox": [ + 194, + 70, + 238, + 189 + ], + "type": "image", + "image_path": "b5b20907eeaf38e9a96ded160117cb4d4b7f0427982cc9648212e2ef623392d9.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 240, + 70, + 285, + 189 + ], + "blocks": [ + { + "bbox": [ + 240, + 70, + 285, + 189 + ], + "lines": [ + { + "bbox": [ + 240, + 70, + 285, + 189 + ], + "spans": [ + { + "bbox": [ + 240, + 70, + 285, + 189 + ], + "type": "image", + "image_path": "640a42b89ce2436a79964101e526c1ae65be753033ac5cdf6dea04b168d815ce.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 256, + 287, + 293 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 256, + 287, + 293 + ], + "spans": [ + { + "bbox": [ + 46, + 256, + 287, + 293 + ], + "type": "text", + "content": "may possess different RGB colors in NeRF rendering under different views [55]. We thus propose an iterative strategy to build clean point clouds from multi-view observations." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 293, + 287, + 329 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 293, + 287, + 329 + ], + "spans": [ + { + "bbox": [ + 46, + 293, + 287, + 329 + ], + "type": "text", + "content": "As in Figure 5, we first build point clouds from the reference view " + }, + { + "bbox": [ + 46, + 293, + 287, + 329 + ], + "type": "inline_equation", + "content": "\\beta_{\\mathrm{ref}}" + }, + { + "bbox": [ + 46, + 293, + 287, + 329 + ], + "type": "text", + "content": " according to the rendered depth " + }, + { + "bbox": [ + 46, + 293, + 287, + 329 + ], + "type": "inline_equation", + "content": "\\mathcal{D}(\\beta_{\\mathrm{ref}})" + }, + { + "bbox": [ + 46, + 293, + 287, + 329 + ], + "type": "text", + "content": " and alpha mask " + }, + { + "bbox": [ + 46, + 293, + 287, + 329 + ], + "type": "inline_equation", + "content": "M(\\beta_{\\mathrm{ref}})" + }, + { + "bbox": [ + 46, + 293, + 287, + 329 + ], + "type": "text", + "content": " of NeRF," + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 79, + 340, + 287, + 354 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 79, + 340, + 287, + 354 + ], + "spans": [ + { + "bbox": [ + 79, + 340, + 287, + 354 + ], + "type": "interline_equation", + "content": "V \\left(\\beta_ {\\text {r e f}}\\right) = R _ {\\text {r e f}} K ^ {- 1} \\mathcal {P} \\left(\\mathcal {D} \\left(\\beta_ {\\text {r e f}}\\right) * M \\left(\\beta_ {\\text {r e f}}\\right)\\right), \\tag {6}", + "image_path": "241b65df14adbc79239de16debb62104a2ef450497879b856e783f3775885f53.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "spans": [ + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "inline_equation", + "content": "R_{\\mathrm{ref}}" + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "text", + "content": " are the extrinsic and intrinsic matrices of the camera, and " + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "inline_equation", + "content": "\\mathcal{P}" + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "text", + "content": " denotes depth-to-point projection. These points are visible under the reference view and thus colorized with ground-truth textures. For the projection of the remaining views " + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "inline_equation", + "content": "\\beta_{i}" + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "text", + "content": ", it is important to avoid introducing points that overlap with existing points but have conflicting colors. To this end, we project the existing points " + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "inline_equation", + "content": "V(\\beta_{\\mathrm{ref}})" + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "text", + "content": " to the novel view " + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "inline_equation", + "content": "\\beta_{i}" + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "text", + "content": " to yield a mask indicating the presence of existing points. With this mask as guidance, we only lift those points " + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "inline_equation", + "content": "V(\\beta_{i})" + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "text", + "content": " that have not been observed yet, as shown in Figure 5. These invisible points are then initialized with coarse textures from NeRF rendering " + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "inline_equation", + "content": "\\mathcal{G}(\\beta_{i})" + }, + { + "bbox": [ + 46, + 365, + 287, + 521 + ], + "type": "text", + "content": " and integrated into the dense point clouds." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "content": "Deferred point cloud rendering. So far, we have built a set of textured point clouds " + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "inline_equation", + "content": "V = \\{V(\\beta_{\\mathrm{ref}}), V(\\beta_1), \\dots, V(\\beta_N)\\}" + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "content": ". Though " + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "inline_equation", + "content": "V(\\beta_{\\mathrm{ref}})" + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "content": " already have high-fidelity textures projected from the reference image, the other points that are occluded in the reference view still suffer smooth textures from the coarse NeRF, as shown in Figure 6. To enhance the texture, we optimize the texture of the other points and constrain novel-view rendering with diffusion prior. Specifically, we optimize a 19-dimensional descriptor " + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "content": " for each point, whose first three dimensions are initialized with the initial RGB colors. To avoid noisy colors and bleeding artifacts [2], we adopt a multi-scale deferred rendering scheme. In particular, given a novel view " + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "content": ", we rasterize the point cloud " + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{V}" + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "content": " for " + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "content": " times to obtain " + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "content": " feature maps " + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "inline_equation", + "content": "I_i" + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "content": " with varying sizes of " + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "inline_equation", + "content": "[W/2^i, H/2^i]" + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "inline_equation", + "content": "i \\in [0, K)" + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "content": ". These feature maps are then concatenated and rendered into an image " + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{I}" + } + ] + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 309, + 70, + 544, + 171 + ], + "blocks": [ + { + "bbox": [ + 309, + 70, + 544, + 171 + ], + "lines": [ + { + "bbox": [ + 309, + 70, + 544, + 171 + ], + "spans": [ + { + "bbox": [ + 309, + 70, + 544, + 171 + ], + "type": "table", + "html": "
ViewsLPIPS↓Contextual↓CLIP↑
DietNeRF [10]30.18315.3464.90%
SinNeRF [56]10.20594.2873.24%
DreamFusion+ [32]10.40752.1582.81%
Point-E [26]1-2.2371.31%
3D-Photo [41]103.4387.65%
Ours-coarse10.14271.7487.50%
Ours-enhanced10.09081.5995.65%
", + "image_path": "320c58fd42b6c3500f9fa038c3c30a89239309828917520b38f7e96ece55e715.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + } + ], + "index": 11 + }, + { + "type": "table", + "bbox": [ + 324, + 223, + 528, + 292 + ], + "blocks": [ + { + "bbox": [ + 305, + 172, + 545, + 218 + ], + "lines": [ + { + "bbox": [ + 305, + 172, + 545, + 218 + ], + "spans": [ + { + "bbox": [ + 305, + 172, + 545, + 218 + ], + "type": "text", + "content": "Table 1: Quantitative comparison on DTU. We compute LPIPS under the reference view, and other two metrics under novel views. LPIPS of Point-E is not reported due to the lack of a defined reference view." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 324, + 223, + 528, + 292 + ], + "lines": [ + { + "bbox": [ + 324, + 223, + 528, + 292 + ], + "spans": [ + { + "bbox": [ + 324, + 223, + 528, + 292 + ], + "type": "table", + "html": "
LPIPS↓Contextual↓CLIP↑
DreamFusion+ [32]0.56493.0784.08%
Point-E [26]-5.3764.36%
Ours-coarse0.23541.9889.06%
Ours-enhanced0.07801.3395.12%
", + "image_path": "e002da114dd743fc6402672427069eb4567e76f476bf3bd0fb22d5d99491dfb6.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_body" + } + ], + "index": 13 + }, + { + "bbox": [ + 311, + 294, + 539, + 305 + ], + "lines": [ + { + "bbox": [ + 311, + 294, + 539, + 305 + ], + "spans": [ + { + "bbox": [ + 311, + 294, + 539, + 305 + ], + "type": "text", + "content": "Table 2: Quantitative comparison on the test benchmark." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 319, + 529, + 331 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 319, + 529, + 331 + ], + "spans": [ + { + "bbox": [ + 306, + 319, + 529, + 331 + ], + "type": "text", + "content": "using a U-Net renderer " + }, + { + "bbox": [ + 306, + 319, + 529, + 331 + ], + "type": "inline_equation", + "content": "\\mathcal{R}_{\\theta}" + }, + { + "bbox": [ + 306, + 319, + 529, + 331 + ], + "type": "text", + "content": " [2] that is jointly optimized:" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 344, + 340, + 484, + 354 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 344, + 340, + 484, + 354 + ], + "spans": [ + { + "bbox": [ + 344, + 340, + 484, + 354 + ], + "type": "interline_equation", + "content": "I _ {i} (\\beta) = \\mathcal {S} (i, V, F, \\beta), i \\in [ 0, K),", + "image_path": "11d3f9db53b63f66237ca9dfde9095cf805e37c13460cee3682f5b341f4359c0.jpg" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 345, + 350, + 545, + 369 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 345, + 350, + 545, + 369 + ], + "spans": [ + { + "bbox": [ + 345, + 350, + 545, + 369 + ], + "type": "interline_equation", + "content": "\\mathbf {I} (\\beta) = \\mathcal {R} _ {\\theta} \\left(I _ {0} (\\beta), I _ {1} (\\beta), \\dots , I _ {K - 1} (\\beta)\\right), \\tag {7}", + "image_path": "681e29acdd96195802c708f393e178cb50c1d2723064cac60057ff6348a2042f.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 376, + 545, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 376, + 545, + 460 + ], + "spans": [ + { + "bbox": [ + 306, + 376, + 545, + 460 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 306, + 376, + 545, + 460 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 306, + 376, + 545, + 460 + ], + "type": "text", + "content": " is a differentiable point rasterizer. The objective of the texture enhancement process is similar to that of the geometry creation discussed in Sec. 3.2, but we additionally include a regularization term that penalizes large differences between the optimized texture and the initial texture. With the texture enhancement process, fine-detailed texture is generated on the occluded points." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 306, + 472, + 387, + 485 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 472, + 387, + 485 + ], + "spans": [ + { + "bbox": [ + 306, + 472, + 387, + 485 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 491, + 438, + 503 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 491, + 438, + 503 + ], + "spans": [ + { + "bbox": [ + 306, + 491, + 438, + 503 + ], + "type": "text", + "content": "4.1. Implementation Details" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 510, + 545, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 510, + 545, + 605 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 545, + 605 + ], + "type": "text", + "content": "NeRF rendering. We use the multi-scale hash encoding from Instant-NGP [25] to implement the NeRF representation in the coarse optimization stage, which enables neural rendering at a computational cost. Similar to Instant-NGP, we maintain an occupancy grid to enable efficient ray sampling by skipping empty space. Additionally, we adopt several shading augmentations on the rendered images, such as Lambertian and normal shading, akin to [32]." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 606, + 545, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 606, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 304, + 606, + 545, + 677 + ], + "type": "text", + "content": "Point cloud rendering. For deferred rendering, we use a 2D U-Net architecture with gated convolutions [60]. The dimension of the point descriptor is 19, where the first 3 dimensions are initialized RGB colors and the remaining dimensions are randomly initialized. We also set a learnable descriptor for the background." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "content": "Camera setting. Following the camera sampling method used in [32], we randomly sample novel views with a " + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "content": " probability and sample the pre-defined reference view with" + } + ] + } + ], + "index": 23 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 741 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 741 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 741 + ], + "type": "text", + "content": "22824" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 47, + 68, + 545, + 304 + ], + "blocks": [ + { + "bbox": [ + 47, + 68, + 545, + 304 + ], + "lines": [ + { + "bbox": [ + 47, + 68, + 545, + 304 + ], + "spans": [ + { + "bbox": [ + 47, + 68, + 545, + 304 + ], + "type": "image", + "image_path": "b29d69849552ba288a44102b49a494deaaa36e5028fa66d0b446221edd1ff428.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 308, + 546, + 334 + ], + "lines": [ + { + "bbox": [ + 46, + 308, + 546, + 334 + ], + "spans": [ + { + "bbox": [ + 46, + 308, + 546, + 334 + ], + "type": "text", + "content": "Figure 7: Qualitative comparison on the test benchmark with two diffusion-based 3D content creation models, Dreamfusion and Point-E. We show our results with high-fidelity geometry and texture. The results of Dreamfusion are from its website." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 47, + 344, + 545, + 456 + ], + "blocks": [ + { + "bbox": [ + 47, + 344, + 545, + 456 + ], + "lines": [ + { + "bbox": [ + 47, + 344, + 545, + 456 + ], + "spans": [ + { + "bbox": [ + 47, + 344, + 545, + 456 + ], + "type": "image", + "image_path": "be88b9d2a005b48ff33408552c42bb60f9a21679ceeb1fbe3b4522725ffb05da.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 460, + 546, + 484 + ], + "lines": [ + { + "bbox": [ + 46, + 460, + 546, + 484 + ], + "spans": [ + { + "bbox": [ + 46, + 460, + 546, + 484 + ], + "type": "text", + "content": "Figure 8: Qualitative comparison of novel view synthesis on DTU with state of the arts. Our method generates sharper and more plausible details in both geometry and texture." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 497, + 287, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 497, + 287, + 521 + ], + "spans": [ + { + "bbox": [ + 46, + 497, + 287, + 521 + ], + "type": "text", + "content": "a " + }, + { + "bbox": [ + 46, + 497, + 287, + 521 + ], + "type": "inline_equation", + "content": "25\\%" + }, + { + "bbox": [ + 46, + 497, + 287, + 521 + ], + "type": "text", + "content": " probability. We also randomly enlarge the FOV when rendering with NeRF, following [18]." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "spans": [ + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "text", + "content": "Score distillation sampling. We randomly sample " + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "text", + "content": " from 0.2 to 0.6, and set " + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "inline_equation", + "content": "w(t)" + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "text", + "content": " as a uniform weighting depending on the timestep. We also use classifier-free guidance with a guidance weight " + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "inline_equation", + "content": "\\omega : \\hat{\\epsilon}_{\\phi}(z_t; y, t) = (1 + \\omega)\\epsilon_{\\phi}(z_t; y, t) - \\omega \\epsilon_{\\phi}(z_t; t)" + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "text", + "content": ". Our method aims to align the created 3D model with the input image, and we use a guidance weight " + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "inline_equation", + "content": "\\omega = 10" + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "text", + "content": ". Training speed. We use Adam [12] with a learning rate of 0.001 for both stages. The coarse stage is trained for 5,000 iterations at a rendering resolution of " + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "inline_equation", + "content": "100 \\times 100" + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "text", + "content": ". The refine stage then takes another 5,000 iterations at a rendering resolution of " + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "inline_equation", + "content": "800 \\times 800" + }, + { + "bbox": [ + 46, + 521, + 287, + 664 + ], + "type": "text", + "content": ". The entire training process takes approximately 2 hours on a single Tesla 32GB V100 GPU." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "content": "Test Benchmark. To the best of our knowledge, we are the first method focusing on high-fidelity 3D creation from an arbitrary image. So we build a test benchmark consisting of 400 images, comprising both real images and images gener-" + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 312, + 495, + 539, + 521 + ], + "blocks": [ + { + "bbox": [ + 312, + 495, + 539, + 521 + ], + "lines": [ + { + "bbox": [ + 312, + 495, + 539, + 521 + ], + "spans": [ + { + "bbox": [ + 312, + 495, + 539, + 521 + ], + "type": "table", + "html": "
Preference RateGeometry QualityTexture QualityFidelity to Input
Ours/DreamFusion+88.2%/11.8%95.6%/4.4%96.5%/3.5%
", + "image_path": "cfda69fecdaf4fed94eaa7b1a8514ef2414c16ab197f6209b2b5cba75b996730.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 523, + 545, + 548 + ], + "lines": [ + { + "bbox": [ + 306, + 523, + 545, + 548 + ], + "spans": [ + { + "bbox": [ + 306, + 523, + 545, + 548 + ], + "type": "text", + "content": "Table 3: Preference rate of geometry quality, texture quality, and fidelity to the input image." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 564, + 545, + 625 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 564, + 545, + 625 + ], + "spans": [ + { + "bbox": [ + 304, + 564, + 545, + 625 + ], + "type": "text", + "content": "ated by Stable Diffusion [38]. Each image in the benchmark is accompanied by a foreground alpha mask, an estimated depth map, and a text prompt. The text prompts for real images are obtained from an image caption model [16]. We will make this test benchmark publicly available." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 634, + 511, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 634, + 511, + 647 + ], + "spans": [ + { + "bbox": [ + 305, + 634, + 511, + 647 + ], + "type": "text", + "content": "4.2. Comparisons with the State of the Arts" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 653, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 714 + ], + "type": "text", + "content": "Baselines. We compare our method with five representative baselines. 1) DietNeRF [10], a few-shot NeRF. We train it with three input views. 2) SinNeRF [56], a single-view NeRF method. 3) DreamFusion [32]. As it is originally conditioned on text prompts, we also modify it with image" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "22825" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 70, + 287, + 189 + ], + "blocks": [ + { + "bbox": [ + 49, + 70, + 287, + 189 + ], + "lines": [ + { + "bbox": [ + 49, + 70, + 287, + 189 + ], + "spans": [ + { + "bbox": [ + 49, + 70, + 287, + 189 + ], + "type": "image", + "image_path": "fdb1db10dd726034626928f6b704f9db1937de2efdf114b83d3bfdda716c4fbb.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 48, + 219, + 286, + 367 + ], + "blocks": [ + { + "bbox": [ + 47, + 194, + 287, + 218 + ], + "lines": [ + { + "bbox": [ + 47, + 194, + 287, + 218 + ], + "spans": [ + { + "bbox": [ + 47, + 194, + 287, + 218 + ], + "type": "text", + "content": "Figure 9: Make-It-3D enables high-fidelity 3D creation on real complex scenes." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 48, + 219, + 286, + 367 + ], + "lines": [ + { + "bbox": [ + 48, + 219, + 286, + 367 + ], + "spans": [ + { + "bbox": [ + 48, + 219, + 286, + 367 + ], + "type": "image", + "image_path": "c9c001c947f2e50eb0c46dc1766dc2509c6b90ede199331059904a1856d7a1f6.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 372, + 287, + 396 + ], + "lines": [ + { + "bbox": [ + 47, + 372, + 287, + 396 + ], + "spans": [ + { + "bbox": [ + 47, + 372, + 287, + 396 + ], + "type": "text", + "content": "Figure 10: Make-It-3D generates diverse and visually stunning 3D models given a text description." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 411, + 287, + 459 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 411, + 287, + 459 + ], + "spans": [ + { + "bbox": [ + 47, + 411, + 287, + 459 + ], + "type": "text", + "content": "reconstruction loss at the reference view, referred as Dream-Fusion+ for fair comparison. 4) Point-E [26], point cloud generation conditioned on image. 5) 3D-Photo [41], depth-based image warping and inpainting method." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 460, + 287, + 639 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 460, + 287, + 639 + ], + "spans": [ + { + "bbox": [ + 47, + 460, + 287, + 639 + ], + "type": "text", + "content": "Qualitative comparison. We first compare our method with 3D generation baselines, where DreamFusion and DreamFusion+ leverage 2D diffusion as 3D prior and PointE is a 3D diffusion model. As shown in Figure 7, their generated models fail to align faithfully with the reference image and suffer smooth textures. In contrast, our method produces high-fidelity 3D models with fine geometry and realistic textures. Figure 8 shows additional comparison on novel view synthesis. SinNeRF and DietNeRF encounter difficulties in reconstructing complex objects due to the lack of multi-view supervision. 3D-Photo fails to reconstruct underlying geometry and produces visible artifacts in large views. In comparison, our method achieves remarkably faithful geometry and visually pleasing textures under novel views." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 641, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 641, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 641, + 287, + 713 + ], + "type": "text", + "content": "Quantitative comparison. A compelling generated 3D model should closely resemble the input image at the reference view, and demonstrate consistent semantics with the reference under novel views. We evaluate these two aspects using the following metrics: 1) LPIPS [61], which assesses the reconstruction quality at the reference view, 2) context-" + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 320, + 69, + 533, + 261 + ], + "blocks": [ + { + "bbox": [ + 320, + 69, + 533, + 261 + ], + "lines": [ + { + "bbox": [ + 320, + 69, + 533, + 261 + ], + "spans": [ + { + "bbox": [ + 320, + 69, + 533, + 261 + ], + "type": "image", + "image_path": "b235b34f868e43e6ec4d9f89e1bdf638b2b702ce1248534aeae001dc1700b358.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 306, + 266, + 545, + 291 + ], + "lines": [ + { + "bbox": [ + 306, + 266, + 545, + 291 + ], + "spans": [ + { + "bbox": [ + 306, + 266, + 545, + 291 + ], + "type": "text", + "content": "Figure 11: Make-It-3D achieves 3D-aware texture modification such as tattoo drawing and stylization." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 303, + 545, + 375 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 303, + 545, + 375 + ], + "spans": [ + { + "bbox": [ + 305, + 303, + 545, + 375 + ], + "type": "text", + "content": "tual distance [21], which measures pixel-level similarity between novel-view rendering and the reference, and 3) CLIP score [33], which evaluates the semantic similarity between the novel view and the reference. As shown in Table 1 and Table 2, our approach substantially outperforms baselines in terms of both reference-view and novel-view quality." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 376, + 545, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 376, + 545, + 460 + ], + "spans": [ + { + "bbox": [ + 305, + 376, + 545, + 460 + ], + "type": "text", + "content": "User study. In order to obtain the user's subjective evaluation of the plausibility of the results, we conduct a user study on 30 participants. In the study, we use 25 pairs of results generated by our method and Dreamfusion+, respectively. All results are presented side-by-side and in a random order to participants. Based on the ratings in Table 3, our method outperformed Dreamfusion+ in all aspects." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 475, + 385, + 488 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 475, + 385, + 488 + ], + "spans": [ + { + "bbox": [ + 306, + 475, + 385, + 488 + ], + "type": "text", + "content": "5. Applications" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 495, + 545, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 495, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 305, + 495, + 545, + 555 + ], + "type": "text", + "content": "Real scene modeling. As shown in Figure 9, Make-It-3D can successfully convert a single photo of a complex scene to a 3D model, such as buildings and landscapes. This empowers users to model a scene with ease, which could be difficult for some traditional 3D modeling techniques." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 556, + 545, + 652 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 556, + 545, + 652 + ], + "spans": [ + { + "bbox": [ + 305, + 556, + 545, + 652 + ], + "type": "text", + "content": "High-quality text-to-3D generation with diversity. Prior arts [32, 18] often produce models with limited diversity and excessively smooth textures. To perform high-quality text-to-3D creation, we first convert the text prompt to a reference image using 2D diffusion, and proceed with our image-based 3D creation method. As shown in Figure 10, Make-It-3D is capable of producing diverse examples from a text prompt that exhibit stunning quality." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 653, + 545, + 713 + ], + "type": "text", + "content": "3D-aware texture modification. Make-It-3D enables view-consistent texture editing by manipulating the reference image in the refine stage while freezing the geometry. Figure 11 shows that we can add a tattoo and apply stylization to the generated 3D model." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 741 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 741 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 741 + ], + "type": "text", + "content": "22826" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 125, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 125, + 83 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 125, + 83 + ], + "type": "text", + "content": "6. Conclusions" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 91, + 289, + 212 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 91, + 289, + 212 + ], + "spans": [ + { + "bbox": [ + 46, + 91, + 289, + 212 + ], + "type": "text", + "content": "We introduce Make-It-3D, a novel two-stage method for creating high-fidelity 3D content from one single image. Leveraging diffusion prior as 3D-aware supervision, the generated 3D models exhibit faithful geometry and realistic textures with the diffusion CLIP loss and textured point cloud enhancement. Make-It-3D is applicable to general objects, empowering versatile fascinating applications. We believe our method takes a big step in extending the success of 2D content creation to 3D, providing users with a fresh 3D creation experience." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 224, + 157, + 239 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 224, + 157, + 239 + ], + "spans": [ + { + "bbox": [ + 47, + 224, + 157, + 239 + ], + "type": "text", + "content": "7. Acknowledgement" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 245, + 287, + 330 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 245, + 287, + 330 + ], + "spans": [ + { + "bbox": [ + 46, + 245, + 287, + 330 + ], + "type": "text", + "content": "The research is supported by National Natural Science Foundation of China (61972157, 72192821), Shanghai Municipal Science and Technology Major Project (2021SHZDZX0102), Shanghai Science and Technology Commission (21511101200), Shanghai Sailing Program (22YF1420300, 23YF1410500) and Young Elite Scientists Sponsorship Program by CAST (2022QNRC001)." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 342, + 107, + 355 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 342, + 107, + 355 + ], + "spans": [ + { + "bbox": [ + 48, + 342, + 107, + 355 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 363, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 53, + 363, + 287, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 363, + 287, + 407 + ], + "spans": [ + { + "bbox": [ + 53, + 363, + 287, + 407 + ], + "type": "text", + "content": "[1] Henrik Aanaes, Rasmus Ramsbøl Jensen, George Vogiatzis, Engin Tola, and Anders Bjorholm Dahl. Large-scale data for multiple-view stereopsis. International Journal of Computer Vision, pages 1-16, 2016. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 408, + 287, + 463 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 408, + 287, + 463 + ], + "spans": [ + { + "bbox": [ + 53, + 408, + 287, + 463 + ], + "type": "text", + "content": "[2] Kara-Ali Aliev, Artem Sevastopolsky, Maria Kolos, Dmitry Ulyanov, and Victor Lempitsky. Neural point-based graphics. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XXII 16, pages 696-712. Springer, 2020. 6" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 465, + 287, + 518 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 465, + 287, + 518 + ], + "spans": [ + { + "bbox": [ + 53, + 465, + 287, + 518 + ], + "type": "text", + "content": "[3] Titas Anciukevicius, Zexiang Xu, Matthew Fisher, Paul Henderson, Hakan Bilen, Niloy J Mitra, and Paul Guerrero. Renderdiffusion: Image diffusion for 3d reconstruction, inpainting and generation. arXiv preprint arXiv:2211.09869, 2022. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 521, + 287, + 576 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 521, + 287, + 576 + ], + "spans": [ + { + "bbox": [ + 53, + 521, + 287, + 576 + ], + "type": "text", + "content": "[4] Yogesh Balaji, Seungjun Nah, Xun Huang, Arash Vahdat, Jiaming Song, Karsten Kreis, Miika Aittala, Timo Aila, Samuli Laine, Bryan Catanzaro, Tero Karras, and Ming-Yu Liu. ediff-i: Text-to-image diffusion models with an ensemble of expert denoisers. ArXiv, abs/2211.01324, 2022. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 578, + 287, + 632 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 578, + 287, + 632 + ], + "spans": [ + { + "bbox": [ + 53, + 578, + 287, + 632 + ], + "type": "text", + "content": "[5] Congyue Deng, Chiyu Jiang, Charles R Qi, Xinchen Yan, Yin Zhou, Leonidas Guibas, Dragomir Anguelov, et al. Nerdi: Single-view nerf synthesis with language-guided diffusion as general image priors. arXiv preprint arXiv:2212.03267, 2022. 3, 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 635, + 287, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 635, + 287, + 678 + ], + "spans": [ + { + "bbox": [ + 53, + 635, + 287, + 678 + ], + "type": "text", + "content": "[6] Steven J Gortler, Radek Grzesczuk, Richard Szeliski, and Michael F Cohen. The lumigraph. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, pages 43-54, 1996. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 53, + 681, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 681, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 53, + 681, + 287, + 713 + ], + "type": "text", + "content": "[7] Tewodros Habtegebrial, Kiran Varanasi, Christian Bailer, and Didier Stricker. Fast view synthesis with deep stereo vision. arXiv preprint arXiv:1804.09690, 2018. 2" + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 27, + "blocks": [ + { + "bbox": [ + 312, + 73, + 545, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 73, + 545, + 117 + ], + "spans": [ + { + "bbox": [ + 312, + 73, + 545, + 117 + ], + "type": "text", + "content": "[8] Yuxuan Han, Ruicheng Wang, and Jiaolong Yang. Single-view synthesis in the wild with learned adaptive multiplane images. In ACM SIGGRAPH 2022 Conference Proceedings, pages 1-8, 2022. 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 312, + 119, + 547, + 172 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 119, + 547, + 172 + ], + "spans": [ + { + "bbox": [ + 312, + 119, + 547, + 172 + ], + "type": "text", + "content": "[9] Ajay Jain, Ben Mildenhall, Jonathan T Barron, Pieter Abbeel, and Ben Poole. Zero-shot text-guided object generation with dream fields. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 867-876, 2022. 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 175, + 547, + 218 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 175, + 547, + 218 + ], + "spans": [ + { + "bbox": [ + 307, + 175, + 547, + 218 + ], + "type": "text", + "content": "[10] Ajay Jain, Matthew Tancik, and Pieter Abbeel. Putting nerf on a diet: Semantically consistent few-shot view synthesis. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 5885-5894, 2021. 2, 6, 7" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 220, + 545, + 295 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 220, + 545, + 295 + ], + "spans": [ + { + "bbox": [ + 307, + 220, + 545, + 295 + ], + "type": "text", + "content": "[11] Varun Jampani, Huiwen Chang, Kyle Sargent, Abhishek Kar, Richard Tucker, Michael Krainin, Dominik Kaeser, William T Freeman, David Salesin, Brian Curless, et al. Slide: Single image 3d photography with soft layering and depth-aware inpainting. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 12518-12527, 2021. 1" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 297, + 545, + 328 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 297, + 545, + 328 + ], + "spans": [ + { + "bbox": [ + 308, + 297, + 545, + 328 + ], + "type": "text", + "content": "[12] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014.7" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 331, + 545, + 363 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 331, + 545, + 363 + ], + "spans": [ + { + "bbox": [ + 308, + 331, + 545, + 363 + ], + "type": "text", + "content": "[13] Han-Hung Lee and Angel X Chang. Understanding pure clip guidance for voxel grid nerf models. arXiv preprint arXiv:2209.15172, 2022. 3" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 365, + 545, + 398 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 365, + 545, + 398 + ], + "spans": [ + { + "bbox": [ + 308, + 365, + 545, + 398 + ], + "type": "text", + "content": "[14] Marc Levoy and Pat Hanrahan. Light field rendering. In Proceedings of the 23rd annual conference on Computer graphics and interactive techniques, pages 31-42, 1996. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 399, + 547, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 399, + 547, + 453 + ], + "spans": [ + { + "bbox": [ + 308, + 399, + 547, + 453 + ], + "type": "text", + "content": "[15] Jiaxin Li, Zijian Feng, Qi She, Henghui Ding, Changhu Wang, and Gim Hee Lee. Mine: Towards continuous depth spi with nerf for novel view synthesis. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 12578-12588, 2021. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 456, + 545, + 499 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 456, + 545, + 499 + ], + "spans": [ + { + "bbox": [ + 308, + 456, + 545, + 499 + ], + "type": "text", + "content": "[16] Junnan Li, Dongxu Li, Silvio Savarese, and Steven Hoi. Blip-2: Bootstrapping language-image pre-training with frozen image encoders and large language models. arXiv preprint arXiv:2301.12597, 2023. 4, 7" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 501, + 545, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 501, + 545, + 533 + ], + "spans": [ + { + "bbox": [ + 308, + 501, + 545, + 533 + ], + "type": "text", + "content": "[17] Qinbo Li and Nima Khademi Kalantari. Synthesizing light field from a single image with variable mpi and two network fusion. ACM Trans. Graph., 39(6):229-1, 2020. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 535, + 545, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 535, + 545, + 588 + ], + "spans": [ + { + "bbox": [ + 308, + 535, + 545, + 588 + ], + "type": "text", + "content": "[18] Chen-Hsuan Lin, Jun Gao, Luming Tang, Towaki Takikawa, Xiaohui Zeng, Xun Huang, Karsten Kreis, Sanja Fidler, Ming-Yu Liu, and Tsung-Yi Lin. Magic3d: High-resolution text-to-3d content creation. arXiv preprint arXiv:2211.10440, 2022. 2, 3, 4, 7, 8" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 590, + 545, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 590, + 545, + 643 + ], + "spans": [ + { + "bbox": [ + 308, + 590, + 545, + 643 + ], + "type": "text", + "content": "[19] Miaomiao Liu, Xuming He, and Mathieu Salzmann. Geometry-aware deep network for single-image novel view synthesis. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4616-4624, 2018. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 647, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 647, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 647, + 545, + 689 + ], + "type": "text", + "content": "[20] Stephen Lombardi, Tomas Simon, Jason Saragih, Gabriel Schwartz, Andreas Lehrmann, and Yaser Sheikh. Neural volumes: Learning dynamic renderable volumes from images. arXiv preprint arXiv:1906.07751, 2019. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 692, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 692, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 692, + 545, + 713 + ], + "type": "text", + "content": "[21] Roey Mechrez, Itamar Talmi, and Lihi Zelnik-Manor. The contextual loss for image transformation with non-aligned" + } + ] + } + ], + "index": 26 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "22827" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "type": "text", + "content": "data. In Proceedings of the European conference on computer vision (ECCV), pages 768-783, 2018. 8" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 95, + 287, + 138 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 95, + 287, + 138 + ], + "spans": [ + { + "bbox": [ + 48, + 95, + 287, + 138 + ], + "type": "text", + "content": "[22] Gal Metzer, Elad Richardson, Or Patashnik, Raja Giryes, and Daniel Cohen-Or. Latent-nerf for shape-guided generation of 3d shapes and textures. arXiv preprint arXiv:2211.07600, 2022. 2, 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 140, + 287, + 193 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 140, + 287, + 193 + ], + "spans": [ + { + "bbox": [ + 48, + 140, + 287, + 193 + ], + "type": "text", + "content": "[23] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. Communications of the ACM, 65(1):99-106, 2021. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 194, + 287, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 194, + 287, + 239 + ], + "spans": [ + { + "bbox": [ + 48, + 194, + 287, + 239 + ], + "type": "text", + "content": "[24] Nasir Mohammad Khalid, Tianhao Xie, Eugene Belilovsky, and Tiberiu Popa. Clip-mesh: Generating textured meshes from text using pretrained image-text models. In SIGGRAPH Asia 2022 Conference Papers, pages 1-8, 2022. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 239, + 287, + 282 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 239, + 287, + 282 + ], + "spans": [ + { + "bbox": [ + 48, + 239, + 287, + 282 + ], + "type": "text", + "content": "[25] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Transactions on Graphics (ToG), 41(4):1-15, 2022. 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 284, + 287, + 326 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 284, + 287, + 326 + ], + "spans": [ + { + "bbox": [ + 48, + 284, + 287, + 326 + ], + "type": "text", + "content": "[26] Alex Nichol, Heewoo Jun, Prafulla Dhariwal, Pamela Mishkin, and Mark Chen. Point-e: A system for generating 3d point clouds from complex prompts. arXiv preprint arXiv:2212.08751, 2022. 1, 6, 8" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 327, + 287, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 327, + 287, + 392 + ], + "spans": [ + { + "bbox": [ + 48, + 327, + 287, + 392 + ], + "type": "text", + "content": "[27] Michael Niemeyer, Jonathan T Barron, Ben Mildenhall, Mehdi SM Sajjadi, Andreas Geiger, and Noha Radwan. Regnerf: Regularizing neural radiance fields for view synthesis from sparse inputs. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5480-5490, 2022. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 394, + 287, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 394, + 287, + 426 + ], + "spans": [ + { + "bbox": [ + 48, + 394, + 287, + 426 + ], + "type": "text", + "content": "[28] Simon Niklaus, Long Mai, Jimei Yang, and Feng Liu. 3d ken burns effect from a single image. ACM Transactions on Graphics (ToG), 38(6):1-15, 2019. 1, 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 426, + 287, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 426, + 287, + 470 + ], + "spans": [ + { + "bbox": [ + 48, + 426, + 287, + 470 + ], + "type": "text", + "content": "[29] Kyle Olszewski, Sergey Tulyakov, Oliver Woodford, Hao Li, and Linjie Luo. Transformable bottleneck networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7648-7657, 2019. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 471, + 287, + 514 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 471, + 287, + 514 + ], + "spans": [ + { + "bbox": [ + 48, + 471, + 287, + 514 + ], + "type": "text", + "content": "[30] Xingang Pan, Bo Dai, Ziwei Liu, Chen Change Loy, and Ping Luo. Do 2d gans know 3d shape? unsupervised 3d shape reconstruction from 2d image gans. arXiv preprint arXiv:2011.00844, 2020. 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 515, + 287, + 569 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 515, + 287, + 569 + ], + "spans": [ + { + "bbox": [ + 48, + 515, + 287, + 569 + ], + "type": "text", + "content": "[31] Eunbyung Park, Jimei Yang, Ersin Yumer, Duygu Ceylan, and Alexander C Berg. Transformation-grounded image generation network for novel 3d view synthesis. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3500-3509, 2017. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 571, + 287, + 603 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 571, + 287, + 603 + ], + "spans": [ + { + "bbox": [ + 48, + 571, + 287, + 603 + ], + "type": "text", + "content": "[32] Ben Poole, Ajay Jain, Jonathan T Barron, and Ben Mildenhall. Dreamfusion: Text-to-3d using 2d diffusion. arXiv preprint arXiv:2209.14988, 2022. 2, 3, 4, 5, 6, 7, 8" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 604, + 287, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 604, + 287, + 668 + ], + "spans": [ + { + "bbox": [ + 48, + 604, + 287, + 668 + ], + "type": "text", + "content": "[33] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International conference on machine learning, pages 8748-8763. PMLR, 2021. 2, 3, 5, 8" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 670, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 287, + 712 + ], + "type": "text", + "content": "[34] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022. 2" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 105 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 105 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 105 + ], + "type": "text", + "content": "[35] René Ranftl, Alexey Bochkovskiy, and Vladlen Koltun. Vision transformers for dense prediction. ArXiv preprint, 2021. 5" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 107, + 545, + 151 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 151 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 151 + ], + "type": "text", + "content": "[36] Konstantinos Rematas, Chuong H Nguyen, Tobias Ritschel, Mario Fritz, and Tinne Tuytelaars. Novel views of objects from a single image. IEEE transactions on pattern analysis and machine intelligence, 39(8):1576-1590, 2016. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 152, + 545, + 185 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 185 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 185 + ], + "type": "text", + "content": "[37] Chris Rockwell, David F. Fouhey, and Justin Johnson. Pixelsynth: Generating a 3d-consistent experience from a single image. In ICCV, 2021. 1" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 186, + 545, + 241 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 186, + 545, + 241 + ], + "spans": [ + { + "bbox": [ + 308, + 186, + 545, + 241 + ], + "type": "text", + "content": "[38] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684-10695, 2022. 1, 2, 4, 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 243, + 545, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 243, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 308, + 243, + 545, + 308 + ], + "type": "text", + "content": "[39] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022. 2, 4" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 310, + 545, + 354 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 310, + 545, + 354 + ], + "spans": [ + { + "bbox": [ + 308, + 310, + 545, + 354 + ], + "type": "text", + "content": "[40] Jonathan Shade, Steven Gortler, Li-wei He, and Richard Szeliski. Layered depth images. In Proceedings of the 25th annual conference on Computer graphics and interactive techniques, pages 231–242, 1998. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 355, + 545, + 408 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 355, + 545, + 408 + ], + "spans": [ + { + "bbox": [ + 308, + 355, + 545, + 408 + ], + "type": "text", + "content": "[41] Meng-Li Shih, Shih-Yang Su, Johannes Kopf, and Jia-Bin Huang. 3d photography using context-aware layered depth inpainting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8028-8038, 2020. 1, 3, 6, 8" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 411, + 545, + 454 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 411, + 545, + 454 + ], + "spans": [ + { + "bbox": [ + 308, + 411, + 545, + 454 + ], + "type": "text", + "content": "[42] Vincent Sitzmann, Michael Zollhöfer, and Gordon Wetzstein. Scene representation networks: Continuous 3d-structure-aware neural scene representations. Advances in Neural Information Processing Systems, 32, 2019. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 456, + 545, + 511 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 456, + 545, + 511 + ], + "spans": [ + { + "bbox": [ + 308, + 456, + 545, + 511 + ], + "type": "text", + "content": "[43] Pratul P Srinivasan, Richard Tucker, Jonathan T Barron, Ravi Ramamoorthi, Ren Ng, and Noah Snively. Pushing the boundaries of view extrapolation with multiplane images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 175-184, 2019. 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 512, + 545, + 567 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 512, + 545, + 567 + ], + "spans": [ + { + "bbox": [ + 308, + 512, + 545, + 567 + ], + "type": "text", + "content": "[44] Pratul P Srinivasan, Tongzhou Wang, Ashwin Sreelal, Ravi Ramamoorthi, and Ren Ng. Learning to synthesize a 4d rgbd light field from a single image. In Proceedings of the IEEE International Conference on Computer Vision, pages 2243-2251, 2017. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 568, + 545, + 622 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 568, + 545, + 622 + ], + "spans": [ + { + "bbox": [ + 308, + 568, + 545, + 622 + ], + "type": "text", + "content": "[45] Shao-Hua Sun, Minyoung Huh, Yuan-Hong Liao, Ning Zhang, and Joseph J Lim. Multi-view to novel view: Synthesizing novel views with self-learned confidence. In Proceedings of the European Conference on Computer Vision (ECCV), pages 155–171, 2018. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 624, + 545, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 624, + 545, + 668 + ], + "spans": [ + { + "bbox": [ + 308, + 624, + 545, + 668 + ], + "type": "text", + "content": "[46] Alex Trevithick and Bo Yang. Grf: Learning a general radiance field for 3d representation and rendering. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 15182-15192, 2021. 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 670, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 670, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 670, + 545, + 713 + ], + "type": "text", + "content": "[47] Richard Tucker and Noah Snively. Single-view view synthesis with multiplane images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 551-560, 2020. 1, 3" + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "22828" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[48] Shubham Tulsiani, Richard Tucker, and Noah Snavely. Layer-structured 3d scene inference via view synthesis. In Proceedings of the European Conference on Computer Vision (ECCV), pages 302–317, 2018. 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 118, + 287, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 118, + 287, + 149 + ], + "spans": [ + { + "bbox": [ + 49, + 118, + 287, + 149 + ], + "type": "text", + "content": "[49] Aaron Van Den Oord, Oriol Vinyals, et al. Neural discrete representation learning. Advances in neural information processing systems, 30, 2017. 4" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 151, + 287, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 151, + 287, + 194 + ], + "spans": [ + { + "bbox": [ + 49, + 151, + 287, + 194 + ], + "type": "text", + "content": "[50] Haochen Wang, Xiaodan Du, Jiahao Li, Raymond A Yeh, and Greg Shakhnarovich. Score jacobian chaining: Lifting pretrained 2d diffusion models for 3d generation. arXiv preprint arXiv:2212.00774, 2022. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 195, + 287, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 195, + 287, + 239 + ], + "spans": [ + { + "bbox": [ + 49, + 195, + 287, + 239 + ], + "type": "text", + "content": "[51] Tengfei Wang, Bo Zhang, Ting Zhang, Shuyang Gu, Jianmin Bao, Tadas Baltrusaitis, Jingjing Shen, Dong Chen, Fang Wen, Qifeng Chen, et al. Rodin: A generative model for sculpting 3d digital avatars using diffusion. CVPR, 2023. 1" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 239, + 287, + 271 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 239, + 287, + 271 + ], + "spans": [ + { + "bbox": [ + 49, + 239, + 287, + 271 + ], + "type": "text", + "content": "[52] Tengfei Wang, Ting Zhang, Bo Zhang, Hao Ouyang, Dong Chen, Qifeng Chen, and Fang Wen. Pretraining is all you need for image-to-image translation. In arXiv, 2022. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 272, + 287, + 316 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 272, + 287, + 316 + ], + "spans": [ + { + "bbox": [ + 49, + 272, + 287, + 316 + ], + "type": "text", + "content": "[53] Daniel Watson, William Chan, Ricardo Martin-Brualla, Jonathan Ho, Andrea Tagliasacchi, and Mohammad Norouzi. Novel view synthesis with diffusion models. arXiv preprint arXiv:2210.04628, 2022. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 317, + 287, + 370 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 317, + 287, + 370 + ], + "spans": [ + { + "bbox": [ + 49, + 317, + 287, + 370 + ], + "type": "text", + "content": "[54] Olivia Wiles, Georgia Gkioxari, Richard Szeliski, and Justin Johnson. Synsin: End-to-end view synthesis from a single image. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7467-7477, 2020. 1, 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 372, + 287, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 372, + 287, + 403 + ], + "spans": [ + { + "bbox": [ + 49, + 372, + 287, + 403 + ], + "type": "text", + "content": "[55] Jiaxin Xie, Hao Ouyang, Jingtan Piao, Chenyang Lei, and Qifeng Chen. High-fidelity 3d gan inversion by pseudomulti-view optimization. CVPR, 2023. 1, 6" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 405, + 287, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 405, + 287, + 470 + ], + "spans": [ + { + "bbox": [ + 49, + 405, + 287, + 470 + ], + "type": "text", + "content": "[56] Dejia Xu, Yifan Jiang, Peihao Wang, Zhiwen Fan, Humphrey Shi, and Zhangyang Wang. Sinnerf: Training neural radiance fields on complex scenes from a single image. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXII, pages 736-753. Springer, 2022. 1, 6, 7" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 472, + 287, + 503 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 472, + 287, + 503 + ], + "spans": [ + { + "bbox": [ + 49, + 472, + 287, + 503 + ], + "type": "text", + "content": "[57] Dejia Xu, Yifan Jiang, Peihao Wang, Zhiwen Fan, Yi Wang, and Zhangyang Wang. Neurallift-360: Lifting an in-the-wild 2d photo to a 3d object with " + }, + { + "bbox": [ + 49, + 472, + 287, + 503 + ], + "type": "inline_equation", + "content": "360^{\\circ}" + }, + { + "bbox": [ + 49, + 472, + 287, + 503 + ], + "type": "text", + "content": " views. 2022. 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 505, + 287, + 557 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 505, + 287, + 557 + ], + "spans": [ + { + "bbox": [ + 49, + 505, + 287, + 557 + ], + "type": "text", + "content": "[58] Lior Yariv, Yoni Kasten, Dror Moran, Meirav Galun, Matan Atzmon, Basri Ronen, and Yaron Lipman. Multiview neural surface reconstruction by disentangling geometry and appearance. Advances in Neural Information Processing Systems, 33:2492-2502, 2020. 4" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 49, + 559, + 287, + 612 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 559, + 287, + 612 + ], + "spans": [ + { + "bbox": [ + 49, + 559, + 287, + 612 + ], + "type": "text", + "content": "[59] Alex Yu, Vickie Ye, Matthew Tancik, and Angjoo Kanazawa. pixelnerf: Neural radiance fields from one or few images. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4578-4587, 2021. 1, 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 49, + 614, + 287, + 658 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 614, + 287, + 658 + ], + "spans": [ + { + "bbox": [ + 49, + 614, + 287, + 658 + ], + "type": "text", + "content": "[60] Jiahui Yu, Zhe Lin, Jamei Yang, Xiaohui Shen, Xin Lu, and Thomas S Huang. Free-form image inpainting with gated convolution. In Proceedings of the IEEE/CVF international conference on computer vision, pages 4471-4480, 2019. 6" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 49, + 659, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 659, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 49, + 659, + 287, + 712 + ], + "type": "text", + "content": "[61] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 586-595, 2018. 8" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 128 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 128 + ], + "type": "text", + "content": "[62] Tinghui Zhou, Shubham Tulsiani, Weilun Sun, Jitendra Malik, and Alexei A Efros. View synthesis by appearance flow. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part IV 14, pages 286-301. Springer, 2016. 2" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "22829" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/4fa47878-d18c-4c5d-89a6-b50ae3093aaf_content_list.json b/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/4fa47878-d18c-4c5d-89a6-b50ae3093aaf_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..e2982b57e9c5bd5100de4d1a3dc92586db113065 --- /dev/null +++ b/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/4fa47878-d18c-4c5d-89a6-b50ae3093aaf_content_list.json @@ -0,0 +1,1275 @@ +[ + { + "type": "text", + "text": "Manipulate by Seeing: Creating Manipulation Controllers from Pre-Trained Representations", + "text_level": 1, + "bbox": [ + 148, + 130, + 821, + 174 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Jianren Wang* Sudeep Dasari* Mohan Kumar Srirama Shubham Tulsiani Abhinav Gupta", + "bbox": [ + 63, + 203, + 919, + 223 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Carnegie Mellon University", + "bbox": [ + 385, + 238, + 620, + 257 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 228, + 291, + 316, + 306 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The field of visual representation learning has seen explosive growth in the past years, but its benefits in robotics have been surprisingly limited so far. Prior work uses generic visual representations as a basis to learn (task-specific) robot action policies (e.g., via behavior cloning). While the visual representations do accelerate learning, they are primarily used to encode visual observations. Thus, action information has to be derived purely from robot data, which is expensive to collect! In this work, we present a scalable alternative where the visual representations can help directly infer robot actions. We observe that vision encoders express relationships between image observations as distances (e.g., via embedding dot product) that could be used to efficiently plan robot behavior. We operationalize this insight and develop a simple algorithm for acquiring a distance function and dynamics predictor, by finetuning a pre-trained representation on human collected video sequences. The final method is able to substantially outperform traditional robot learning baselines (e.g., $70\\%$ success v.s. $50\\%$ for behavior cloning on pick-place) on a suite of diverse real-world manipulation tasks. It can also generalize to novel objects, without using any robot demonstrations during train time. For visualizations of the learned policies please check: https://agi-labs.github.io/manipulate-by-seeing/.", + "bbox": [ + 76, + 321, + 473, + 717 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 744, + 227, + 762 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The lack of suitable, large-scale data-sets is a major bottleneck in robot learning. Due to the physical nature of data collection, robotics data-sets are: (a) hard to scale; (b) collected in sterile, non-realistic environments (e.g. robotics lab); (c) too homogeneous (e.g. toy objects with fixed backgrounds/lighting). In contrast, vision data-sets contain diverse tasks, objects,", + "bbox": [ + 75, + 770, + 468, + 878 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/6539cafe82d4a0cd000cfd89ebcd050b34681416a30c0dabc063f42b2c8cb00b.jpg", + "image_caption": [ + "Figure 1: This paper proposes to solve a range of manipulation tasks (e.g. pushing) by learning a functional distance metric within the embedding space of a pretrained network. This distance function - in combination with a learned dynamics model - can be used to greedily plan for robot actions that reach a goal state. Our experiments reveal that the proposed method can outperform SOTA robot learning methods across four diverse manipulation tasks." + ], + "image_footnote": [], + "bbox": [ + 501, + 290, + 890, + 474 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "and settings (e.g. Ego4D [14]). Therefore, recent approaches have explored transferring priors from large scale vision data-sets to robotics settings. What is the right way to accomplish this?", + "bbox": [ + 496, + 654, + 892, + 717 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Prior work uses vision data-sets to pre-train representations [31, 29, 32] that encode image observations as state vectors (i.e. $s = R(i)$ ). This visual representation is then simply used as an input for a controller learned from robot data - e.g. a policy $\\pi(a|s)$ , trained with expert data via Behavior Cloning [35], or a Value function $V(s)$ , trained using exploratory roll-outs via Reinforcement Learning [43]. Is this approach the most efficient way to use pre-trained representations? We argue that pre-trained networks can do more than just represent states, since their latent space already encodes semantic, task-level information - e.g. by plac", + "bbox": [ + 496, + 719, + 893, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Denotes equal contribution.", + "bbox": [ + 94, + 886, + 272, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "3859", + "bbox": [ + 482, + 924, + 514, + 936 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "ing semantically similar states more closely together. Leveraging this structure to infer actions, could enable us to use significantly less robotic data during train time.", + "bbox": [ + 75, + 90, + 468, + 150 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Our paper achieves this by fine-tuning a pre-trained representation into: (a) a one-step dynamics module, $F(s,a)$ , that predicts how the robot's next state given the current state/action; and (b) a \"functional distance module\", $d(s,g)$ , that calculates how close the robot is to achieving its goal $g$ in the state $s$ . The distance function is learned with limited human demonstration data, using a contrastive learning objective (see Fig. 2). Both $d$ and $F$ are used in conjunction to greedily plan robot actions (see Fig. 1 for intuition). Our experiments demonstrate that this approach works better than policy learning (via Behavior Cloning), because the pre-trained representation itself does the heavy lifting (thanks to its structure) and we entirely dodge the challenge of multi-modal, sequential action prediction. Furthermore, our learned distance function is both stable and easy to train, which allows it to easily scale and generalize to new scenarios.", + "bbox": [ + 75, + 152, + 470, + 422 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To summarize, we show a simple approach for exploiting the information hidden in pre-trained visual representations. Our contributions include:", + "bbox": [ + 76, + 425, + 468, + 470 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- Developing a simple algorithm for acquiring a distance function and dynamics model by fine-tuning a pre-trained visual representation on minimal (human collected) data.", + "- Creating an effective manipulation controller that substantially outperforms State-of-the-Art (SOTA) prior methods from the robot learning community (e.g. Behavior Cloning [35], Offline-RL [20], etc.).", + "- Demonstrating that our approach can handle four realistic manipulation tasks, generalize to new objects and settings, and solve challenging scenarios w/ multi-modal action distributions." + ], + "bbox": [ + 93, + 483, + 468, + 707 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 76, + 723, + 241, + 739 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Behavior Cloning This paper adopts the Learning from Demonstration (LfD) problem setting [4, 7, 36], where a robot must acquire manipulation behaviors given expert demonstration trajectories. A standard approach in this space is to learn a policy $(\\pi)$ via Behavior Cloning [35] (BC), which directly optimizes $\\pi$ to match the expert's action distribution. While conceptually simple, realistic action distributions are difficult to model, since they are inherently multi-modal and even small errors compound over time. Thus, policy", + "bbox": [ + 75, + 750, + 470, + 902 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "learning requires extensive intensive network engineering (e.g. transformer architectures [10, 9], multi-modal prediction heads [41, 27], etc.) and/or human-in-the-loop data collection algorithms [35, 18] to work in practice. Instead of learning a policy, we learn a functional distance metric that captures the how “close” a state is to reaching a target goal. This lets us build a manipulation controller using a simple greedy planner during test time, without any explicit action prediction!", + "bbox": [ + 496, + 90, + 893, + 227 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Offline RL Broadly speaking, the field of Reinforcement Learning [43] (RL) seeks to learn a value/advantage/Q function by assuming access to a reward signal, which \"evaluates\" a state (e.g. $+1$ reward for reaching goal). RL algorithms usually require environment interaction to learn, though the field of Offline-RL [25] seeks to extend these systems to learn from offline trajectories. While these approaches have created some impressive robotics demos ranging from locomotion [24, 22] to dexterous manipulation [2, 16, 11], RL methods are data hungry [33, 2], difficult to implement, require extreme \"reward engineering\" (e.g. MetaWorld [49] reward functions are 50 lines!), hampered by unstable learning dynamics [21], and poorly generalize in realistic robotic manipulation settings [12]. In contrast, our method learns a proxy for value functions (i.e. distances) purely from offline data, using representation learning algorithms (from the vision field) that are much more stable.", + "bbox": [ + 496, + 250, + 893, + 537 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Learning Visual Rewards Our distance learning approach is analogous to learning visual rewards. Prior work learned success classifiers [40, 47, 46] and/or video similarity metrics [39, 5, 37, 6, 8] from expert video demonstrations. Once learned, these modules were used to parameterize reward functions that could be used to train policies [1], and/or as cost functions for planners [3]. However, these papers mostly consider simple settings (e.g. simulation) or require the test setting to exactly match train time. This is because the learned reward functions are often noisy and/or poorly generalize to new scenes. In contrast, our learned distance metric is stable and can easily adapt to new scenarios, thanks to the pre-trained network's latent structure. This allows us to solve diverse tasks during test time on a real robot, using a simple (and fast) shooting method planner.", + "bbox": [ + 496, + 560, + 893, + 818 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Distance Learning for Navigation Finally, prior work from Hahn et. al. [15] explored distance learning to solve visual navigation tasks from offline video data. Our work is inspired from this approach, but makes", + "bbox": [ + 496, + 839, + 893, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "3860", + "bbox": [ + 482, + 924, + 516, + 936 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "three key innovations in order to apply it to (more challenging) robotic manipulation tasks. First, we simplify the network architecture to operate in representation space instead of using a graph network. Second, we learn the distances using a self-supervised contrastive loss, instead of relying on hand-defined objectives. And third, we add a dynamics function that proves to be critical for effective manipulation (see Table. 3).", + "bbox": [ + 75, + 90, + 472, + 213 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Methods", + "text_level": 1, + "bbox": [ + 76, + 227, + 191, + 243 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Preliminaries This paper considers learning goal-conditioned manipulation behaviors from image observations. The robot agent is provided a goal observation $(I_g) - \\mathrm{e.g.}$ target object in robot gripper - and an observation $(I_t)$ for the current time-step $t$ . The robot must process these observations and decide an action to take $(a_{t})$ . Note that all observations $(I)$ are wrist-mounted RGB camera images with no depth or proprioceptive data. Additionally, the actions $(a)$ are specified as arbitrary $SE(3)$ transforms for the robot's end-effector (more in Supplement B.1). Our goal is to learn a robotic manipulation controller, using a set of training trajectories $\\mathcal{D} = \\{\\tau_1,\\dots ,\\tau_N\\}$ , where $\\tau_{i} = \\{I_{g},I_{1},a_{1},\\ldots ,a_{T - 1},I_{T}\\}$ . The test and train settings are visualized in Fig. 4.", + "bbox": [ + 75, + 253, + 472, + 481 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Our Approach Our method leverages a pre-trained representation network, $R$ , to encode observations, $i_{t} = R(I_{t})$ , and enable control via distance learning. Specifically, we use contrastive representation learning methods [30, 28] to learn a distance metric, $d(i_j,i_k)$ within the pre-trained embedding space. The key idea is to use this distance metric to select which of the possible future state is closest to the goal state. But how do we predict possible future states? We explicitly learn a dynamics function, $F(i_{t},a_{t})$ that predicts future state for a possible action $a_{t}$ . During test time, we predict multiple future states using different possible action and select the one which is closest to goal state. The following sections describe the learned dynamics module (see Sec. 3.1), distance learning method (see Sec. 3.2), and test-time controller for robot deployment (see Sec. 3.4) in detail. Fig. 2 provides a visual depiction of our training algorithm. Pseudo-code and hyper-parameters are presented in Supplement A.3.", + "bbox": [ + 75, + 502, + 472, + 791 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Dynamics Prediction", + "text_level": 1, + "bbox": [ + 76, + 801, + 274, + 816 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "An ideal dynamics function would perfectly capture how a robot's actions effects its environment. In our setting, this translates to predicting the next observation embedding, given the current embedding and commanded action: $F(i_{t},a_{t}) = i_{t + 1}$ . Thus, $F$ can", + "bbox": [ + 75, + 824, + 470, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "be learned via regression by minimizing reconstruction loss in embedding space: $\\mathcal{L}_F = ||F(i_t,a_t) - i_{t + 1}||_2$ (see Fig. 2, left). This module has two primary uses: (1) during training it acts as a physically grounded regularizer that relays action information into the embedding space, and (2) during test time it enables the robot to plan actions in embedding space. As you will see, both properties are leveraged extensively in the rest of our method.", + "bbox": [ + 496, + 90, + 893, + 227 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Learning Task-Centric Distances", + "text_level": 1, + "bbox": [ + 500, + 237, + 790, + 253 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Our distance module $d(i_j, i_k)$ seeks to learn functional distances that encode task-centric reasoning (e.g. must reach for object before pushing it) alongside important physical priors (e.g. object is to the left so move left). How can we learn such a distance space? Since we have access to expert trajectories $\\tau$ , we know that the next state sequentially visited by the expert $(i_{t+1})$ is closer to the goal state $(i_g)$ than arbitrary states $(\\hat{i})$ reachable from $i_t$ - i.e. $d(i_{t+1}, i_g) << d(\\hat{i}, i_g)$ .", + "bbox": [ + 496, + 260, + 890, + 398 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Our insight is that a distance metric with these properties can be learned via contrastive learning. Specifically, we define $d(i_j,i_k) = -\\cos (i_j,i_k)$ , where $\\cos$ is cosine similarity, and sample a observation-state-goal tuples $(i_t,a_t,i_g)$ , alongside random noise action candidates $\\hat{a}^1,\\dots ,\\hat{a}^n$ sampled from $\\mathcal{D}$ . We apply NCE loss and get:", + "bbox": [ + 496, + 400, + 890, + 503 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {d} = \\frac {e x p (- d (F (i _ {t} , a _ {t}) , i _ {g}))}{e x p (- d (F (i _ {t} , a _ {t}) , i _ {g})) + \\Sigma_ {j} e x p (- d (F (i _ {t} , \\hat {a} ^ {j}) , i _ {g}))}\n$$\n", + "text_format": "latex", + "bbox": [ + 501, + 516, + 890, + 550 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "This loss creates a warped embedding space where $i_{t+1}$ (hallucinated by $F(i_t, a_t)$ ) is pushed closer towards the goal state $i_g$ , than other arbitrary states reachable from $i_t$ (again hallucinated by $F$ ). This process is shown visually in Fig. 2 (right), and precisely satisfies our criteria for good distance functions.", + "bbox": [ + 496, + 559, + 890, + 650 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.3. Training Details", + "text_level": 1, + "bbox": [ + 500, + 661, + 661, + 678 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Both modules are trained jointly resulting in a final loss: $\\mathcal{L} = \\lambda_d\\mathcal{L}_d + \\lambda_F\\mathcal{L}_F$ . Note that $F$ is implemented as small neural networks with 2 hidden layers, while $d$ does not require any extra learned networks since its implemented via contrastive loss in the metric space. The shared representation network, $R$ , we use is ResNet-18 initialized by R3M weights. The ADAM [19] stochastic gradient descent optimizer and back-propagation are used to train the network end-to-end. Please refer to Supplement A.3. for additional details.", + "bbox": [ + 496, + 684, + 890, + 835 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.4. Test Time Robot Deployment", + "text_level": 1, + "bbox": [ + 500, + 845, + 761, + 863 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "During test time our learned modules must be able to solve real manipulation tasks when deployed on", + "bbox": [ + 498, + 869, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "3861", + "bbox": [ + 482, + 924, + 513, + 936 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/32f761e924347836ca27401d5c09e7df302aec3f4171515ac4a5a774f87e7248.jpg", + "image_caption": [ + "Figure 2: We visualize the loss functions used to train our method. The dynamics function is trained via reconstruction loss in embedding space (left). The distance function is trained via contrastive learning, with positive anchors chosen by predicting the next state using the ground truth action, $F(i_{t},a_{t})$ , and predicting negative pairs chosen using noisy actions $F(i_{t},\\hat{a}^{j})$ ." + ], + "image_footnote": [], + "bbox": [ + 80, + 85, + 395, + 354 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/e72a925803eadf711bbeeaba45553b5648caa668defcebe0c95d8ffda2fdb103.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 398, + 85, + 890, + 349 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "robot hardware. Thus, we develop a simple inference policy that solves for robot actions using our learned distance and dynamics function. First, a cost function $C_g(i) = d(i,i_g)$ is parameterized given a goal observation $I_{g}$ and the learned distance function. $C_g$ encodes how far an arbitrary image observation is from the goal image. The optimal action, $a_{t}^{*}$ , will take the robot closest to the goal, hence: $a_{t}^{*} = \\mathbf{argmin}_{a}C_{g}(F(i_{t},a))$ . Note that we use the dynamics function $F$ to predict the next state, since we do not know the real $i_{t + 1}^{*}$ during test time. The cost minimization is performed using the shooting method: random candidate actions, $a_1,\\ldots ,a_N$ , are sampled from $\\mathcal{D}$ , passed through the dynamics function, and the action with minimum cost $C_g(F(i_t,a_i))$ is executed on the robot. This process is illustrated in Fig. 1. Policy execution ends once the distance between the current state and the goal falls below a threshold value: $C_g(i_t) < \\lambda$ . While a more complicated planner could've been used, this solution was adopted due to its speed, simplicity, lack of hyperparameters, and good empirical performance.", + "bbox": [ + 75, + 450, + 472, + 768 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The final detail to discuss is gripper control for prehensile tasks (e.g. pick and place). Since the gripper status is binary (open/close) and highly correlated with the current state (i.e. close when object in hand), it makes more sense to handle it implicitly rather than as part of the action command $a_{t}$ . Thus, we trained a gripper action classifier $\\mathcal{G}(i_t)\\in [0,1]$ that predicts the probability of closing the gripper given the current", + "bbox": [ + 75, + 779, + 468, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "image embedding. This is also implemented by adding a single layer to ResNet-18 initialized by R3M weights and can be trained using a small amount $(< 100)$ of human labelled images from the train dataset $\\mathcal{D}$ . As a result, our system can seamlessly handle gripper control in prehensile tasks, without requiring gripper labels for every frame in $\\mathcal{D}$ !", + "bbox": [ + 496, + 450, + 892, + 555 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. Experimental Setup", + "text_level": 1, + "bbox": [ + 500, + 568, + 720, + 585 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Our method is tested on four different manipulation tasks (see Fig. 3) that require a mix of high-level reasoning (e.g. go to object before target), low level precision (must carefully grab knob to turn it), and time-time generalization (e.g. push novel object). We collect behavior data for each task from human demonstrators as described below. The trained policies are deployed on a real Franka Pandas robot (see Fig. 4, right). Additional details on the hardware setup and control stack are presented in Supplement B.1.", + "bbox": [ + 496, + 594, + 893, + 744 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Tasks", + "text_level": 1, + "bbox": [ + 500, + 753, + 578, + 768 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We now introduce the tasks used in our experiments (pictured in Fig. 3), and provide more details on their train and test conditions:", + "bbox": [ + 500, + 777, + 890, + 821 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Pushing For this task (see Fig. 3a) the robot must approach a novel object placed on the table and push it to the goal location (marked by target printout). Training: Our method was trained on a dataset of", + "bbox": [ + 496, + 839, + 893, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "3862", + "bbox": [ + 482, + 924, + 514, + 936 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/35a211cc8cb76b0991a26470b1cd2874927bded007aee8718ee9872a7c06c8ce.jpg", + "image_caption": [ + "(a) Pushing" + ], + "image_footnote": [], + "bbox": [ + 84, + 88, + 281, + 203 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/47d95f914e85a5422d588c3490040c63cd4d8567afd47eed5d3035afd28fa48c.jpg", + "image_caption": [ + "(b) Pick and Place", + "Figure 3: Our method is tested on 4 different manipulation tasks (pictured above). These tasks test different skill axis, ranging from task-level reasoning (e.g. detect target, move to object before goal, etc.) to fine-grained motor control (e.g. grab top of knob to turn)." + ], + "image_footnote": [], + "bbox": [ + 282, + 88, + 480, + 203 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/7a835bb50752f27737dfb01a7e97828ac3ccc28fbe9827a599d4760db54f73b3.jpg", + "image_caption": [ + "(c) Door Opening" + ], + "image_footnote": [], + "bbox": [ + 482, + 88, + 679, + 203 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/d7899741b36d8f2259b203af305fe17a144a3690eaae68b6b571561702b70fd2.jpg", + "image_caption": [ + "(d) Knob Turning" + ], + "image_footnote": [], + "bbox": [ + 681, + 88, + 880, + 203 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/bd1a213a787e7f17cde1cd7006fdff6eaa84d3258431ffd949eca61a437763ac.jpg", + "image_caption": [ + "Low-Cost Human Videos Transferred to Robot", + "Figure 4: In our problem setting we use a low-cost reacher grabber tool (left) to collect training demonstrations. These demonstrations are used to acquire a robot controller purely through distance/representation learning. The final system is deployed on a robot (right) to solve various tasks at test-time." + ], + "image_footnote": [], + "bbox": [ + 78, + 327, + 470, + 467 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "100 demonstrations with diverse objects and randomized targets. Testing: During test time, the method was evaluated using 20 trails that involved unseen objects and new target printouts placed in randomly sampled positions. A trail is deemed successful if the robot pushes the object onto the target. This is the only task that did not require gripper control.", + "bbox": [ + 75, + 595, + 468, + 703 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Pick and Place This task (see Fig. 3b) is analogous to the pushing task (described above), except the robot must now pick the object up from its initial location and place it in a target bowl. This task requires more precision than pushing, since grasping an object is harder than localizing it. Training: We collect a dataset of 400 demonstrations for training, using randomized train objects and target bowls. Testing: The method is evaluated using 20 trails that used novel objects and unseen target bowls (i.e. analogous to pushing). A trail is successful if the robot places an object into the target.", + "bbox": [ + 75, + 719, + 470, + 901 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Door Opening The opening task (see Fig. 3c) requires the robot to approach a handle, grasp it, and then pull the door open. While conceptually simple, this task requires a great deal of precision, since the commanded actions must (almost) exactly match the direction of the door hinge. Training: We created a toy kitchen setting for this task, and collected 100 demonstrations of opening the door when starting from various initial positions. Testing: We evaluated on 20 real world test trials, where the robot's initial position and the door's initial state (e.g. position and hinge angle) were randomized. A trial was deemed successful if the door is opened fully.", + "bbox": [ + 496, + 304, + 893, + 502 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Knob Turning In this final task (see Fig. 3d) the robot must approach a knob in the toy kitchen, and then turn it clock-wise. Similar to the opening task, knob turning requires very precise motor control, since the robot must grab the knob at exactly the right location and carefully rotate in order to turn. Training: We collect a dataset of 100 knob turning demonstrations. Testing: The method is evaluated on 20 trials, with randomized robot/knob initial positions. Success is determined by if the knob is turned far enough to cause an audible \"click.\"", + "bbox": [ + 496, + 518, + 893, + 686 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Robot-Free Data Collection", + "text_level": 1, + "bbox": [ + 500, + 696, + 746, + 710 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "A major strength of our setup is that training data $(\\mathcal{D})$ can come from a different agent than the test time robot. We leverage this property to collect videos directly from humans operating a low-cost grabber stick (see Fig. 4, left), and use structure from motion [38] to recover actions. This allows us to collect demonstrations without an expensive tele-op setup [50, 23] or time-intensive kinesthetic demonstrations (i.e. manually moving the robot by hand). While based on prior work, our stick setup makes two important contributions: it is easier build and use than the highly instrumented setup in Song et. al. [42], and it provides higher", + "bbox": [ + 496, + 719, + 893, + 902 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "3863", + "bbox": [ + 482, + 924, + 514, + 936 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/8398b4afcf5be3c6f62a7c638a54e947fbf983308453f164d06f921b3c078d57.jpg", + "image_caption": [ + "Figure 5: Trajectories executed on the robot using our learned distance function. For each task, we show the $1^{st}$ person view (top) and $3^{rd}$ person view images (bottom). We show the learned visual embedding can encode functional distances between states for challenging tasks, like pushing, pick and place, door opening, and knob turning." + ], + "image_footnote": [], + "bbox": [ + 84, + 87, + 893, + 648 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "quality images and action labels than the GoPro used in Young et. al. [48]. Please refer to Supplement A.2 for more information on our training and testing setups. We will release our dataset publicly.", + "bbox": [ + 75, + 746, + 470, + 809 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 76, + 827, + 228, + 845 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The following experiments seek to validate our distance learning framework on real control tasks (described above), and give some fundamental insights", + "bbox": [ + 75, + 854, + 470, + 902 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "as to why they work. First, our baseline study (see Sec. 5.1) compares our method against representative SOTA techniques in the field. In addition, in Sec. 5.2 we analyze a specific scenario with highly multi-modal actions, where our model especially shines. Finally, the ablation study (see Sec. 5.3) investigates which components of our system are actually needed for good performance.", + "bbox": [ + 496, + 746, + 893, + 867 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "3864", + "bbox": [ + 482, + 924, + 514, + 936 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/9483390e884922a6ff730ef68a2153aa8d0594ef7e1a9084d875926f2607b67d.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
TaskOursBC [35, 48]IBC [13]IQL [20]
Pushing85%70%70%65%
Pick and Place60%30%30%45%
Door Opening55%40%45%50%
Knob Turning40%20%20%35%
", + "bbox": [ + 78, + 89, + 462, + 167 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/5fd876afc676a6c143269ecf5e3dce3942a7b5051e824604a7818fae6f8c1ff9.jpg", + "table_caption": [ + "Table 1: We compare success rates for our method versus the baselines on all four manipulation tasks. Our distance learning method outperforms a suite of representative robot learning baselines." + ], + "table_footnote": [], + "table_body": "
# DemosPushingPick and Place
OursBCIBCOursBCIBC
5070%50%40%0%0%0%
10085%70%70%10%10%0%
20090%80%100%20%20%10%
400100%100%100%60%30%30%
600100%100%100%70%50%40%
", + "bbox": [ + 78, + 252, + 464, + 354 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 2: We compare our distance learning method versus the behavior cloning baselines (BC [35, 48] and IBC [13]) when trained on varying amounts of data. Distance learning is able to learn faster than the baselines and scale better with data.", + "bbox": [ + 75, + 364, + 468, + 441 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.1. Baseline Study", + "text_level": 1, + "bbox": [ + 76, + 467, + 227, + 483 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We first note that our paper uses only demonstration data and no online data. Therefore, we compare our method against three SOTA baselines - ranging from standard behavior cloning, to energy based modeling, and Offline Reinforcement Learning (RL) - that cover a wide range of prior LfD work. The baseline methods are described briefly below. To make the comparisons fair, we parameterize all neural networks with the same R3M representation backbone used by our method, and tune hyper-parameters for best possible performance. Please check Supplement B.2 for in depth details.", + "bbox": [ + 75, + 489, + 468, + 657 + ], + "page_idx": 6 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- Behavior Cloning [35, 48] (BC): BC learns a policy (via regression) that directly predicts actions from image observations: $\\min_{\\pi}||\\pi(I_t,I_g) - a_t||_2$ . This provides a strong comparison point for a whole class of LfD methods that focus on learning motor policies directly.", + "- Implicit Behavior Cloning [13] (IBC): IBC learns an energy based model that can predict actions during test time via optimization: $a_{t} = \\operatorname{argmin}_{a} E(a, I_{t}, I_{g})$ . This method is conceptually very similar to behavior cloning, but has the potential to better handle multi-modal action distributions and discontinuous actions.", + "- Implicit Q-Learning [20] (IQL): IQL is an" + ], + "bbox": [ + 93, + 667, + 468, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "offline-RL baseline that learns a Q function $Q(s,a) = Q((I_t,I_g),a_t)$ , alongside a policy that maximizes it $\\pi (I_t,I_g) = \\arg \\max_aQ(s,a)$ . Note that IQL's training process requires us to annotate our offline trajectories $\\mathcal{D}$ with a reward signal $r_t$ for each time-step. While this can be done automatically in our setting (Supplement B.2), this is an additional assumption that could be very burdensome in the general case.", + "bbox": [ + 529, + 90, + 890, + 227 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Our method is compared against the baselines on all four of our tasks (see Sec. 4.1). Results are reported in Table 1. Note how our distance learning approach achieves the highest success rates on all of four tasks. In addition, our method is much simpler than the strongest baseline (IQL), which requires an expert defined reward signal and uses a more complicated learning algorithm. The final test time performance is visualized in Fig. 5 and on our website: https://agilabs.github.io/manipulate-by-seeing/.", + "bbox": [ + 496, + 234, + 893, + 387 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Data Scaling A common cited strength of BC (versus RL) is its ability to continuously improve with additional expert data. Can our method do the same? Table 2 compares our distance learning method versus the BC/IBC baselines (on pushing/pick-place tasks), when trained on various amounts of data. Note how our method both learns faster than BC/IBC, and continuously scales with added demonstrations. This suggests that distance learning is a powerful alternative to BC on robotic manipulation tasks, no matter how much training data is available.", + "bbox": [ + 496, + 401, + 893, + 568 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.2. Multi-Modality Experiment", + "text_level": 1, + "bbox": [ + 500, + 575, + 751, + 590 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "A common challenge in policy learning is effectively handling multi-modal action predictions. We propose a simple test scenario that allows us to test our method in this setting without any other confounding variables. Specifically, we create a \"obstacle pushing\" task where the robot must push an object to the target without disturbing an obstacle placed in the middle (see Fig. 6). Observe that there are two equally valid ways that the robot could push the block; to the left or to the right. We collect a training dataset of 100 demos, equally split between going left and right. This creates action multi-modality where the agent must arbitrarily choose between two scenarios in order to successfully perform the task, but will fail if it simply averages the actions and pushes the block forward (into the obstacle). We expect that standard BC will fall into this failure mode, since it is trained using standard L2 action regression. In contrast, our method should still work since the low distance states will move the robot either to the left or right state, thus allowing it to make a discrete choice.", + "bbox": [ + 496, + 598, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "3865", + "bbox": [ + 482, + 924, + 514, + 936 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/eee2abf71c645549d93ea0e946d29a3a02e616b71efbba8900beafd4e890dd0d.jpg", + "image_caption": [ + "Figure 6: Our method can solve tasks with highly multi-modal action distributions that are difficult for the baselines. In this example, our distance learning controller successfully pushes the block around the obstacle, while Behavior Cloning learns to incorrectly push the block forward (i.e. predicts mean action)." + ], + "image_footnote": [], + "bbox": [ + 117, + 89, + 426, + 328 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "To verify this hypothesis, we test our method, the BC baseline, and IQL (the strongest non-BC baseline) on 20 trials in this task setting. Success is judged similarly as to pushing (see Sec. 4.1), with the added condition that the robot should not push the obstacles into the target. Our method achieves a $95\\%$ success rate, versus $0\\%$ for BC and $90\\%$ for IQL in this setting! As expected, our method is able to greatly improve upon BC in this setting, because it explicitly avoids action prediction. While IQL should not suffer as badly from multi-modality, thanks to its learned value function, our method is still able to outperform it despite being simpler algorithmically and trained without reward signal.", + "bbox": [ + 75, + 458, + 468, + 667 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.3. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 680, + 228, + 696 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Our final experiment removes components of our method in order to determine which parts were most crucial for control performance. The representation ablation replaces the R3M backbone in our neural network with a pre-trained ImageNet representation (using same ResNet-18 architecture for both). We expect the ImageNet weights to be weaker, since they were trained on a smaller dataset that did not include egocentric videos (ImageNet vs Ego4D used by R3M). Additionally, the dynamics ablation removes the dynamics module during training, thus leaving the distance model/embeddings without any physical grounding. This is similar to the method from Hahn et. al. [15] (see", + "bbox": [ + 75, + 704, + 468, + 902 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/a0ec1a5ede47a1b7f02678a1c6a7b61553a2dd654ddc389933dcac40ea4815a4.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
OursImageNet Repr.No Dynamics [15]
Pushing90%40%60%
Pick and Place60%40%35%
Door Opening55%45%50%
Knob Turning40%15%40%
", + "bbox": [ + 501, + 89, + 885, + 162 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 3: This table compares success rates for our method versus the ablations on the all four tasks. As you can see, removing the dynamics module from our method during training and training with a weaker representation both result in worse performance.", + "bbox": [ + 496, + 175, + 890, + 250 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Sec. 2), with an added dynamics module. We expect this ablation to perform worse on manipulation tasks, because dynamics is more important in this setting v.s. visual navigation.", + "bbox": [ + 496, + 277, + 890, + 339 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "The two ablations are evaluated and compared against our method on all four test tasks (see Table 3). We find that our method strongly outperforms both of our baselines, which suggests that our intuition outline above is correct. In particular, we conclude that stronger representations can directly stronger control performance using our method. Additionally, this shows that the dynamics grounding is important to ensure that our learned distances transfer onto real robot hardware during test time, especially in manipulation tasks that involve object interactions/contact.", + "bbox": [ + 496, + 339, + 890, + 505 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Discussion", + "text_level": 1, + "bbox": [ + 500, + 521, + 629, + 537 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "This paper demonstrates that neural image representations can be more than just state representations: a simple metric defined within the embedding space can help infer robot actions. We leverage this insight to learn a distance function and dynamics function using minimal low-cost human data. These modules parameterize a robotic planner that is validated across 4 representative manipulation tasks. Despite its simplicity, our method is able to outperform standard imitation learning and offline-RL methods in the robot learning field. This is especially true in situations involving multi-modal action distributions, where our method entirely outclasses a standard BC baseline. Finally, the ablation study demonstrates that stronger representations directly result in stronger control performance, and that dynamics grounding is important for our scheme to work in practice.", + "bbox": [ + 496, + 547, + 890, + 804 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Future Work We hope that this paper inspires future work in the space of representation learning and robotics. Follow up works should improve visual representations specifically for robotics, by more precisely capturing fine-grained interactions between gripper/-", + "bbox": [ + 496, + 824, + 890, + 902 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "3866", + "bbox": [ + 482, + 924, + 514, + 936 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "hand and objects. This could improve performance on tasks like knob turning, where the pre-trained R3M encoder often struggled to detect small shifts of the gripper relative to the knob. We also hope that our contrastive learning method could be extended to learn entirely without action labels. This would allow us to train on large scale manipulation datasets (e.g. YouTube videos) and transfer the results directly to the control setting. Finally, it would be ideal if data collected using our low-cost stick (see Fig. 4) could be used with a stronger, more reliable (commercial) gripper, despite the domain gap. This would enable us to solve more tasks during test time.", + "bbox": [ + 75, + 90, + 472, + 287 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 303, + 184, + 318 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Pieter Abbeel and Andrew Y Ng. Apprenticeship learning via inverse reinforcement learning. In Proceedings of the twenty-first international conference on Machine learning, page 1, 2004.", + "[2] OpenAI: Marcin Andrychowicz, Bowen Baker, Maciek Chociej, Rafal Jozefowicz, Bob McGrew, Jakub Pachocki, Arthur Petron, Matthias Plappert, Glenn Powell, Alex Ray, et al. Learning dexterous in-hand manipulation. The International Journal of Robotics Research, 39(1):3-20, 2020.", + "[3] Daniel Angelov, Yordan Hristov, Michael Burke, and Subramanian Ramamoorthy. Composing diverse policies for temporally extended tasks. IEEE Robotics and Automation Letters, 5(2):2658-2665, 2020.", + "[4] Brenna D Argall, Sonia Chernova, Manuela Veloso, and Brett Browning. A survey of robot learning from demonstration. Robotics and autonomous systems, 57(5):469-483, 2009.", + "[5] Yusuf Aytar, Tobias Pfaff, David Budden, Thomas Paine, Ziyu Wang, and Nando De Freitas. Playing hard exploration games by watching youtube. Advances in neural information processing systems, 31, 2018.", + "[6] Shikhar Bahl, Abhinav Gupta, and Deepak Pathak. Human-to-robot imitation in the wild. RSS, 2022.", + "[7] Aude Billard, Sylvain Calinon, Ruediger Dillmann, and Stefan Schaal. Survey: Robot programming by demonstration. Handbook of robotics, 59(BOOK_CHAP), 2008.", + "[8] Annie S Chen, Suraj Nair, and Chelsea Finn. Learning generalizable robotic reward functions from\" in-the-wild\" human videos. arXiv preprint arXiv:2103.16817, 2021.", + "[9] Lili Chen, Kevin Lu, Aravind Rajeswaran, Kimin Lee, Aditya Grover, Misha Laskin, Pieter Abbeel, Aravind Srinivas, and Igor Mordatch. Decision transformer: Reinforcement learning via sequence modeling. Advances in neural information processing systems, 34:15084-15097, 2021.", + "[10] Sudeep Dasari and Abhinav Gupta. Transformers for one-shot imitation learning. In CoRL 2020, 2020." + ], + "bbox": [ + 78, + 328, + 470, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[11] Sudeep Dasari, Abhinav Gupta, and Vikash Kumar. Learning dexterous manipulation from exemplar object trajectories and pre-grasps. In IEEE International Conference on Robotics and Automation 2023, 2023.", + "[12] Sudeep Dasari, Jianren Wang, Joyce Hong, Shikhar Bahl, Yixin Lin, Austin Wang, Abitha Thankaraj, Karanbir Chahal, Berk Calli, Saurabh Gupta, et al. Rb2: Robotic manipulation benchmarking with a twist. arXiv preprint arXiv:2203.08098, 2022.", + "[13] Pete Florence, Corey Lynch, Andy Zeng, Oscar Ramirez, Ayzaan Wahid, Laura Downs, Adrian Wong, Johnny Lee, Igor Mordatch, and Jonathan Tompson. Implicit behavioral cloning. Conference on Robot Learning (CoRL), 2021.", + "[14] Kristen Grauman, Andrew Westbury, Eugene Byrne, Zachary Chavis, Antonino Furnari, Rohit Girdhar, Jackson Hamburger, Hao Jiang, Miao Liu, Xingyu Liu, et al. Ego4d: Around the world in 3,000 hours of egocentric video. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18995-19012, 2022.", + "[15] Meera Hahn, Devendra Singh Chaplot, Shubham Tulsiani, Mustafa Mukadam, James M Rehg, and Abhinav Gupta. No rl, no simulation: Learning to navigate without navigating. Advances in Neural Information Processing Systems, 34:26661-26673, 2021.", + "[16] Ankur Handa, Arthur Allshire, Viktor Makoviychuk, Aleksei Petrenko, Ritvik Singh, Jingzhou Liu, Denys Makoviichuk, Karl Van Wyk, Alexander Zhurkevich, Balakumar Sundaralingam, Yashraj Narang, Jean-Francois Lafleche, Dieter Fox, and Gavriel State. Dextreme: Transfer of agile in-hand manipulation from simulation to reality. arXiv, 2022.", + "[17] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016.", + "[18] Eric Jang, Alex Irpan, Mohi Khansari, Daniel Kappler, Frederik Ebert, Corey Lynch, Sergey Levine, and Chelsea Finn. Bc-z: Zero-shot task generalization with robotic imitation learning. In Conference on Robot Learning, pages 991-1002. PMLR, 2022.", + "[19] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014.", + "[20] Ilya Kostrikov, Ashvin Nair, and Sergey Levine. Offline reinforcement learning with implicit q-learning. arXiv preprint arXiv:2110.06169, 2021.", + "[21] Aviral Kumar, Rishabh Agarwal, Dibya Ghosh, and Sergey Levine. Implicit under-parameterization inhibits data-efficient deep reinforcement learning. arXiv preprint arXiv:2010.14498, 2020.", + "[22] Ashish Kumar, Zipeng Fu, Deepak Pathak, and Jitendra Malik. Rma: Rapid motor adaptation for legged robots. arXiv preprint arXiv:2107.04034, 2021.", + "[23] Vikash Kumar and Emanuel Todorov. Mujoco haptix: A virtual reality system for hand manipulation. In" + ], + "bbox": [ + 503, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "3867", + "bbox": [ + 482, + 925, + 514, + 936 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Humanoid Robots (Humanoids), 2015 IEEE-RAS 15th International Conference on, pages 657-663. IEEE, 2015.", + "[24] Joonho Lee, Jemin Hwangbo, Lorenz Wellhausen, Vladlen Koltun, and Marco Hutter. Learning quadrupedal locomotion over challenging terrain. Science robotics, 5(47):eabc5986, 2020.", + "[25] Sergey Levine, Aviral Kumar, George Tucker, and Justin Fu. Offline reinforcement learning: Tutorial, review, and perspectives on open problems. arXiv preprint arXiv:2005.01643, 2020.", + "[26] Yixin Lin and Austin Wang. Polymetis: a real-time pytorch controller manager. In https://github.com/facebookresearch/polymetis, 2021.", + "[27] Corey Lynch, Mohi Khansari, Ted Xiao, Vikash Kumar, Jonathan Tompson, Sergey Levine, and Pierre Sermanet. Learning latent plans from play. In Conference on robot learning, pages 1113-1132. PMLR, 2020.", + "[28] Andriy Mnih and Koray Kavukcuoglu. Learning word embeddings efficiently with noise-contrastive estimation. Advances in neural information processing systems, 26, 2013.", + "[29] Suraj Nair, Aravind Rajeswaran, Vikash Kumar, Chelsea Finn, and Abhinav Gupta. R3m: A universal visual representation for robot manipulation. CoRL, 2022.", + "[30] Aaron van den Oord, Yazhe Li, and Oriol Vinyals. Representation learning with contrastive predictive coding. arXiv preprint arXiv:1807.03748, 2018.", + "[31] Simone Parisi, Aravind Rajeswaran, Senthil Purushwalkam, and Abhinav Gupta. The unsurprising effectiveness of pre-trained vision models for control. arXiv preprint arXiv:2203.03580, 2022.", + "[32] Ilija Radosavovic, Tete Xiao, Stephen James, Pieter Abbeel, Jitendra Malik, and Trevor Darrell. Realworld robot learning with masked visual pre-training. CoRL, 2022.", + "[33] Aravind Rajeswaran, Vikash Kumar, Abhishek Gupta, Giulia Vezzani, John Schulman, Emanuel Todorov, and Sergey Levine. Learning complex dexterous manipulation with deep reinforcement learning and demonstrations. arXiv preprint arXiv:1709.10087, 2017.", + "[34] Frank Rosenblatt. Principles of neurodynamics. perceptrons and the theory of brain mechanisms. Technical report, Cornell Aeronautical Lab Inc Buffalo NY, 1961.", + "[35] Stéphane Ross, Geoffrey Gordon, and Drew Bagnell. A reduction of imitation learning and structured prediction to no-regret online learning. In Proceedings of the fourteenth international conference on artificial intelligence and statistics, pages 627-635, 2011.", + "[36] Stefan Schaal. Is imitation learning the route to humanoid robots? Trends in cognitive sciences, 3(6):233-242, 1999.", + "[37] Karl Schmeckpeper, Oleh Rybkin, Kostas Daniilidis, Sergey Levine, and Chelsea Finn. Reinforcement learning with videos: Combining offline observations with" + ], + "bbox": [ + 78, + 90, + 470, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "interaction. In Conference on Robot Learning, pages 339-354. PMLR, 2021.", + "[38] Johannes Lutz Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In Conference on Computer Vision and Pattern Recognition (CVPR), 2016.", + "[39] Pierre Sermanet, Corey Lynch, Yevgen Chebotar, Jasmine Hsu, Eric Jang, Stefan Schaal, Sergey Levine, and Google Brain. Time-contrastive networks: Self-supervised learning from video. In 2018 IEEE international conference on robotics and automation (ICRA), pages 1134–1141. IEEE, 2018.", + "[40] Pierre Sermanet, Kelvin Xu, and Sergey Levine. Unsupervised perceptual rewards for imitation learning. arXiv preprint arXiv:1612.06699, 2016.", + "[41] Nur Muhammad Mahi Shafiullah, Zichen Jeff Cui, Ariuntuya Altanzaya, and Lerrel Pinto. Behavior transformers: Cloning $k$ modes with one stone. In Thirty-Sixth Conference on Neural Information Processing Systems, 2022.", + "[42] Shuran Song, Andy Zeng, Johnny Lee, and Thomas Funkhouser. Grasping in the wild: Learning 6 dof closed-loop grasping from low-cost demonstrations. Robotics and Automation Letters, 2020.", + "[43] Richard S Sutton and Andrew G Barto. Reinforcement learning: An introduction. MIT press, 2018.", + "[44] Michita Imai Takuma Seno. d3rlpy: An offline deep reinforcement library. In NeurIPS 2021 Offline Reinforcement Learning Workshop, December 2021.", + "[45] Emanuel Todorov, Tom Erez, and Yuval Tassa. Mu-joco: A physics engine for model-based control. In 2012 IEEE/RSJ international conference on intelligent robots and systems, pages 5026-5033. IEEE, 2012.", + "[46] Faraz Torabi, Garrett Warnell, and Peter Stone. Generative adversarial imitation from observation. arXiv preprint arXiv:1807.06158, 2018.", + "[47] Annie Xie, Avi Singh, Sergey Levine, and Chelsea Finn. Few-shot goal inference for visuomotor learning and planning. In Conference on Robot Learning, pages 40-52. PMLR, 2018.", + "[48] Sarah Young, Dhiraj Gandhi, Shubham Tulsiani, Abhinav Gupta, Pieter Abbeel, and Lerrel Pinto. Visual imitation made easy. In Conference on Robot Learning, pages 1992-2005. PMLR, 2021.", + "[49] Tianhe Yu, Deirdre Quillen, Zhanpeng He, Ryan Julian, Karol Hausman, Chelsea Finn, and Sergey Levine. Meta-world: A benchmark and evaluation for multi-task and meta reinforcement learning. In _Conference on Robot Learning (CoRL)_, 2019.", + "[50] Tianhao Zhang, Zoe McCarthy, Owen Jow, Dennis Lee, Xi Chen, Ken Goldberg, and Pieter Abbeel. Deep imitation learning for complex manipulation tasks from virtual reality teleoperation. In 2018 IEEE International Conference on Robotics and Automation (ICRA), pages 5628-5635. IEEE, 2018." + ], + "bbox": [ + 503, + 92, + 890, + 869 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "3868", + "bbox": [ + 482, + 925, + 514, + 936 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/4fa47878-d18c-4c5d-89a6-b50ae3093aaf_model.json b/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/4fa47878-d18c-4c5d-89a6-b50ae3093aaf_model.json new file mode 100644 index 0000000000000000000000000000000000000000..1107b86c24f308e74ebfb988986c01218e8f8cf0 --- /dev/null +++ b/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/4fa47878-d18c-4c5d-89a6-b50ae3093aaf_model.json @@ -0,0 +1,1925 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.149, + 0.131, + 0.823, + 0.175 + ], + "angle": 0, + "content": "Manipulate by Seeing: Creating Manipulation Controllers from Pre-Trained Representations" + }, + { + "type": "text", + "bbox": [ + 0.065, + 0.204, + 0.92, + 0.224 + ], + "angle": 0, + "content": "Jianren Wang* Sudeep Dasari* Mohan Kumar Srirama Shubham Tulsiani Abhinav Gupta" + }, + { + "type": "text", + "bbox": [ + 0.386, + 0.239, + 0.621, + 0.258 + ], + "angle": 0, + "content": "Carnegie Mellon University" + }, + { + "type": "title", + "bbox": [ + 0.23, + 0.292, + 0.318, + 0.308 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.323, + 0.474, + 0.718 + ], + "angle": 0, + "content": "The field of visual representation learning has seen explosive growth in the past years, but its benefits in robotics have been surprisingly limited so far. Prior work uses generic visual representations as a basis to learn (task-specific) robot action policies (e.g., via behavior cloning). While the visual representations do accelerate learning, they are primarily used to encode visual observations. Thus, action information has to be derived purely from robot data, which is expensive to collect! In this work, we present a scalable alternative where the visual representations can help directly infer robot actions. We observe that vision encoders express relationships between image observations as distances (e.g., via embedding dot product) that could be used to efficiently plan robot behavior. We operationalize this insight and develop a simple algorithm for acquiring a distance function and dynamics predictor, by finetuning a pre-trained representation on human collected video sequences. The final method is able to substantially outperform traditional robot learning baselines (e.g., \\(70\\%\\) success v.s. \\(50\\%\\) for behavior cloning on pick-place) on a suite of diverse real-world manipulation tasks. It can also generalize to novel objects, without using any robot demonstrations during train time. For visualizations of the learned policies please check: https://agi-labs.github.io/manipulate-by-seeing/." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.746, + 0.228, + 0.763 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.771, + 0.47, + 0.879 + ], + "angle": 0, + "content": "The lack of suitable, large-scale data-sets is a major bottleneck in robot learning. Due to the physical nature of data collection, robotics data-sets are: (a) hard to scale; (b) collected in sterile, non-realistic environments (e.g. robotics lab); (c) too homogeneous (e.g. toy objects with fixed backgrounds/lighting). In contrast, vision data-sets contain diverse tasks, objects," + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.291, + 0.892, + 0.476 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.486, + 0.895, + 0.622 + ], + "angle": 0, + "content": "Figure 1: This paper proposes to solve a range of manipulation tasks (e.g. pushing) by learning a functional distance metric within the embedding space of a pretrained network. This distance function - in combination with a learned dynamics model - can be used to greedily plan for robot actions that reach a goal state. Our experiments reveal that the proposed method can outperform SOTA robot learning methods across four diverse manipulation tasks." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.655, + 0.893, + 0.718 + ], + "angle": 0, + "content": "and settings (e.g. Ego4D [14]). Therefore, recent approaches have explored transferring priors from large scale vision data-sets to robotics settings. What is the right way to accomplish this?" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.895, + 0.902 + ], + "angle": 0, + "content": "Prior work uses vision data-sets to pre-train representations [31, 29, 32] that encode image observations as state vectors (i.e. \\( s = R(i) \\)). This visual representation is then simply used as an input for a controller learned from robot data - e.g. a policy \\( \\pi(a|s) \\), trained with expert data via Behavior Cloning [35], or a Value function \\( V(s) \\), trained using exploratory roll-outs via Reinforcement Learning [43]. Is this approach the most efficient way to use pre-trained representations? We argue that pre-trained networks can do more than just represent states, since their latent space already encodes semantic, task-level information - e.g. by plac" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.274, + 0.9 + ], + "angle": 0, + "content": "*Denotes equal contribution." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.925, + 0.516, + 0.937 + ], + "angle": 0, + "content": "3859" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.151 + ], + "angle": 0, + "content": "ing semantically similar states more closely together. Leveraging this structure to infer actions, could enable us to use significantly less robotic data during train time." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.153, + 0.471, + 0.424 + ], + "angle": 0, + "content": "Our paper achieves this by fine-tuning a pre-trained representation into: (a) a one-step dynamics module, \\( F(s,a) \\), that predicts how the robot's next state given the current state/action; and (b) a \"functional distance module\", \\( d(s,g) \\), that calculates how close the robot is to achieving its goal \\( g \\) in the state \\( s \\). The distance function is learned with limited human demonstration data, using a contrastive learning objective (see Fig. 2). Both \\( d \\) and \\( F \\) are used in conjunction to greedily plan robot actions (see Fig. 1 for intuition). Our experiments demonstrate that this approach works better than policy learning (via Behavior Cloning), because the pre-trained representation itself does the heavy lifting (thanks to its structure) and we entirely dodge the challenge of multi-modal, sequential action prediction. Furthermore, our learned distance function is both stable and easy to train, which allows it to easily scale and generalize to new scenarios." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.426, + 0.47, + 0.471 + ], + "angle": 0, + "content": "To summarize, we show a simple approach for exploiting the information hidden in pre-trained visual representations. Our contributions include:" + }, + { + "type": "text", + "bbox": [ + 0.094, + 0.484, + 0.47, + 0.545 + ], + "angle": 0, + "content": "- Developing a simple algorithm for acquiring a distance function and dynamics model by fine-tuning a pre-trained visual representation on minimal (human collected) data." + }, + { + "type": "text", + "bbox": [ + 0.094, + 0.558, + 0.47, + 0.635 + ], + "angle": 0, + "content": "- Creating an effective manipulation controller that substantially outperforms State-of-the-Art (SOTA) prior methods from the robot learning community (e.g. Behavior Cloning [35], Offline-RL [20], etc.)." + }, + { + "type": "text", + "bbox": [ + 0.094, + 0.647, + 0.47, + 0.708 + ], + "angle": 0, + "content": "- Demonstrating that our approach can handle four realistic manipulation tasks, generalize to new objects and settings, and solve challenging scenarios w/ multi-modal action distributions." + }, + { + "type": "list", + "bbox": [ + 0.094, + 0.484, + 0.47, + 0.708 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.724, + 0.242, + 0.74 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Behavior Cloning This paper adopts the Learning from Demonstration (LfD) problem setting [4, 7, 36], where a robot must acquire manipulation behaviors given expert demonstration trajectories. A standard approach in this space is to learn a policy \\((\\pi)\\) via Behavior Cloning [35] (BC), which directly optimizes \\(\\pi\\) to match the expert's action distribution. While conceptually simple, realistic action distributions are difficult to model, since they are inherently multi-modal and even small errors compound over time. Thus, policy" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.895, + 0.228 + ], + "angle": 0, + "content": "learning requires extensive intensive network engineering (e.g. transformer architectures [10, 9], multi-modal prediction heads [41, 27], etc.) and/or human-in-the-loop data collection algorithms [35, 18] to work in practice. Instead of learning a policy, we learn a functional distance metric that captures the how “close” a state is to reaching a target goal. This lets us build a manipulation controller using a simple greedy planner during test time, without any explicit action prediction!" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.25, + 0.895, + 0.538 + ], + "angle": 0, + "content": "Offline RL Broadly speaking, the field of Reinforcement Learning [43] (RL) seeks to learn a value/advantage/Q function by assuming access to a reward signal, which \"evaluates\" a state (e.g. \\(+1\\) reward for reaching goal). RL algorithms usually require environment interaction to learn, though the field of Offline-RL [25] seeks to extend these systems to learn from offline trajectories. While these approaches have created some impressive robotics demos ranging from locomotion [24, 22] to dexterous manipulation [2, 16, 11], RL methods are data hungry [33, 2], difficult to implement, require extreme \"reward engineering\" (e.g. MetaWorld [49] reward functions are 50 lines!), hampered by unstable learning dynamics [21], and poorly generalize in realistic robotic manipulation settings [12]. In contrast, our method learns a proxy for value functions (i.e. distances) purely from offline data, using representation learning algorithms (from the vision field) that are much more stable." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.561, + 0.895, + 0.819 + ], + "angle": 0, + "content": "Learning Visual Rewards Our distance learning approach is analogous to learning visual rewards. Prior work learned success classifiers [40, 47, 46] and/or video similarity metrics [39, 5, 37, 6, 8] from expert video demonstrations. Once learned, these modules were used to parameterize reward functions that could be used to train policies [1], and/or as cost functions for planners [3]. However, these papers mostly consider simple settings (e.g. simulation) or require the test setting to exactly match train time. This is because the learned reward functions are often noisy and/or poorly generalize to new scenes. In contrast, our learned distance metric is stable and can easily adapt to new scenarios, thanks to the pre-trained network's latent structure. This allows us to solve diverse tasks during test time on a real robot, using a simple (and fast) shooting method planner." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Distance Learning for Navigation Finally, prior work from Hahn et. al. [15] explored distance learning to solve visual navigation tasks from offline video data. Our work is inspired from this approach, but makes" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.925, + 0.517, + 0.937 + ], + "angle": 0, + "content": "3860" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.214 + ], + "angle": 0, + "content": "three key innovations in order to apply it to (more challenging) robotic manipulation tasks. First, we simplify the network architecture to operate in representation space instead of using a graph network. Second, we learn the distances using a self-supervised contrastive loss, instead of relying on hand-defined objectives. And third, we add a dynamics function that proves to be critical for effective manipulation (see Table. 3)." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.228, + 0.192, + 0.244 + ], + "angle": 0, + "content": "3. Methods" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.254, + 0.473, + 0.482 + ], + "angle": 0, + "content": "Preliminaries This paper considers learning goal-conditioned manipulation behaviors from image observations. The robot agent is provided a goal observation \\((I_g) - \\mathrm{e.g.}\\) target object in robot gripper - and an observation \\((I_t)\\) for the current time-step \\(t\\). The robot must process these observations and decide an action to take \\((a_{t})\\). Note that all observations \\((I)\\) are wrist-mounted RGB camera images with no depth or proprioceptive data. Additionally, the actions \\((a)\\) are specified as arbitrary \\(SE(3)\\) transforms for the robot's end-effector (more in Supplement B.1). Our goal is to learn a robotic manipulation controller, using a set of training trajectories \\(\\mathcal{D} = \\{\\tau_1,\\dots ,\\tau_N\\}\\), where \\(\\tau_{i} = \\{I_{g},I_{1},a_{1},\\ldots ,a_{T - 1},I_{T}\\}\\). The test and train settings are visualized in Fig. 4." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.503, + 0.473, + 0.792 + ], + "angle": 0, + "content": "Our Approach Our method leverages a pre-trained representation network, \\( R \\), to encode observations, \\( i_{t} = R(I_{t}) \\), and enable control via distance learning. Specifically, we use contrastive representation learning methods [30, 28] to learn a distance metric, \\( d(i_j,i_k) \\) within the pre-trained embedding space. The key idea is to use this distance metric to select which of the possible future state is closest to the goal state. But how do we predict possible future states? We explicitly learn a dynamics function, \\( F(i_{t},a_{t}) \\) that predicts future state for a possible action \\( a_{t} \\). During test time, we predict multiple future states using different possible action and select the one which is closest to goal state. The following sections describe the learned dynamics module (see Sec. 3.1), distance learning method (see Sec. 3.2), and test-time controller for robot deployment (see Sec. 3.4) in detail. Fig. 2 provides a visual depiction of our training algorithm. Pseudo-code and hyper-parameters are presented in Supplement A.3." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.802, + 0.275, + 0.817 + ], + "angle": 0, + "content": "3.1. Dynamics Prediction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.471, + 0.903 + ], + "angle": 0, + "content": "An ideal dynamics function would perfectly capture how a robot's actions effects its environment. In our setting, this translates to predicting the next observation embedding, given the current embedding and commanded action: \\( F(i_{t},a_{t}) = i_{t + 1} \\). Thus, \\( F \\) can" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.895, + 0.228 + ], + "angle": 0, + "content": "be learned via regression by minimizing reconstruction loss in embedding space: \\(\\mathcal{L}_F = ||F(i_t,a_t) - i_{t + 1}||_2\\) (see Fig. 2, left). This module has two primary uses: (1) during training it acts as a physically grounded regularizer that relays action information into the embedding space, and (2) during test time it enables the robot to plan actions in embedding space. As you will see, both properties are leveraged extensively in the rest of our method." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.238, + 0.792, + 0.254 + ], + "angle": 0, + "content": "3.2. Learning Task-Centric Distances" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.261, + 0.892, + 0.4 + ], + "angle": 0, + "content": "Our distance module \\( d(i_j, i_k) \\) seeks to learn functional distances that encode task-centric reasoning (e.g. must reach for object before pushing it) alongside important physical priors (e.g. object is to the left so move left). How can we learn such a distance space? Since we have access to expert trajectories \\( \\tau \\), we know that the next state sequentially visited by the expert \\( (i_{t+1}) \\) is closer to the goal state \\( (i_g) \\) than arbitrary states \\( (\\hat{i}) \\) reachable from \\( i_t \\) - i.e. \\( d(i_{t+1}, i_g) << d(\\hat{i}, i_g) \\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.401, + 0.892, + 0.505 + ], + "angle": 0, + "content": "Our insight is that a distance metric with these properties can be learned via contrastive learning. Specifically, we define \\( d(i_j,i_k) = -\\cos (i_j,i_k) \\), where \\( \\cos \\) is cosine similarity, and sample a observation-state-goal tuples \\( (i_t,a_t,i_g) \\), alongside random noise action candidates \\( \\hat{a}^1,\\dots ,\\hat{a}^n \\) sampled from \\( \\mathcal{D} \\). We apply NCE loss and get:" + }, + { + "type": "equation", + "bbox": [ + 0.502, + 0.517, + 0.891, + 0.551 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {d} = \\frac {e x p (- d (F (i _ {t} , a _ {t}) , i _ {g}))}{e x p (- d (F (i _ {t} , a _ {t}) , i _ {g})) + \\Sigma_ {j} e x p (- d (F (i _ {t} , \\hat {a} ^ {j}) , i _ {g}))}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.56, + 0.892, + 0.651 + ], + "angle": 0, + "content": "This loss creates a warped embedding space where \\( i_{t+1} \\) (hallucinated by \\( F(i_t, a_t) \\)) is pushed closer towards the goal state \\( i_g \\), than other arbitrary states reachable from \\( i_t \\) (again hallucinated by \\( F \\)). This process is shown visually in Fig. 2 (right), and precisely satisfies our criteria for good distance functions." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.662, + 0.662, + 0.679 + ], + "angle": 0, + "content": "3.3. Training Details" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.685, + 0.892, + 0.837 + ], + "angle": 0, + "content": "Both modules are trained jointly resulting in a final loss: \\(\\mathcal{L} = \\lambda_d\\mathcal{L}_d + \\lambda_F\\mathcal{L}_F\\). Note that \\(F\\) is implemented as small neural networks with 2 hidden layers, while \\(d\\) does not require any extra learned networks since its implemented via contrastive loss in the metric space. The shared representation network, \\(R\\), we use is ResNet-18 initialized by R3M weights. The ADAM [19] stochastic gradient descent optimizer and back-propagation are used to train the network end-to-end. Please refer to Supplement A.3. for additional details." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.847, + 0.762, + 0.864 + ], + "angle": 0, + "content": "3.4. Test Time Robot Deployment" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "During test time our learned modules must be able to solve real manipulation tasks when deployed on" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.925, + 0.514, + 0.937 + ], + "angle": 0, + "content": "3861" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.087, + 0.396, + 0.355 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.399, + 0.087, + 0.892, + 0.351 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.363, + 0.893, + 0.424 + ], + "angle": 0, + "content": "Figure 2: We visualize the loss functions used to train our method. The dynamics function is trained via reconstruction loss in embedding space (left). The distance function is trained via contrastive learning, with positive anchors chosen by predicting the next state using the ground truth action, \\( F(i_{t},a_{t}) \\), and predicting negative pairs chosen using noisy actions \\( F(i_{t},\\hat{a}^{j}) \\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.451, + 0.473, + 0.769 + ], + "angle": 0, + "content": "robot hardware. Thus, we develop a simple inference policy that solves for robot actions using our learned distance and dynamics function. First, a cost function \\( C_g(i) = d(i,i_g) \\) is parameterized given a goal observation \\( I_{g} \\) and the learned distance function. \\( C_g \\) encodes how far an arbitrary image observation is from the goal image. The optimal action, \\( a_{t}^{*} \\), will take the robot closest to the goal, hence: \\( a_{t}^{*} = \\mathbf{argmin}_{a}C_{g}(F(i_{t},a)) \\). Note that we use the dynamics function \\( F \\) to predict the next state, since we do not know the real \\( i_{t + 1}^{*} \\) during test time. The cost minimization is performed using the shooting method: random candidate actions, \\( a_1,\\ldots ,a_N \\), are sampled from \\( \\mathcal{D} \\), passed through the dynamics function, and the action with minimum cost \\( C_g(F(i_t,a_i)) \\) is executed on the robot. This process is illustrated in Fig. 1. Policy execution ends once the distance between the current state and the goal falls below a threshold value: \\( C_g(i_t) < \\lambda \\). While a more complicated planner could've been used, this solution was adopted due to its speed, simplicity, lack of hyperparameters, and good empirical performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.47, + 0.903 + ], + "angle": 0, + "content": "The final detail to discuss is gripper control for prehensile tasks (e.g. pick and place). Since the gripper status is binary (open/close) and highly correlated with the current state (i.e. close when object in hand), it makes more sense to handle it implicitly rather than as part of the action command \\( a_{t} \\). Thus, we trained a gripper action classifier \\( \\mathcal{G}(i_t)\\in [0,1] \\) that predicts the probability of closing the gripper given the current" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.451, + 0.893, + 0.556 + ], + "angle": 0, + "content": "image embedding. This is also implemented by adding a single layer to ResNet-18 initialized by R3M weights and can be trained using a small amount \\((< 100)\\) of human labelled images from the train dataset \\(\\mathcal{D}\\). As a result, our system can seamlessly handle gripper control in prehensile tasks, without requiring gripper labels for every frame in \\(\\mathcal{D}\\)!" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.569, + 0.722, + 0.587 + ], + "angle": 0, + "content": "4. Experimental Setup" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.595, + 0.895, + 0.746 + ], + "angle": 0, + "content": "Our method is tested on four different manipulation tasks (see Fig. 3) that require a mix of high-level reasoning (e.g. go to object before target), low level precision (must carefully grab knob to turn it), and time-time generalization (e.g. push novel object). We collect behavior data for each task from human demonstrators as described below. The trained policies are deployed on a real Franka Pandas robot (see Fig. 4, right). Additional details on the hardware setup and control stack are presented in Supplement B.1." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.755, + 0.58, + 0.769 + ], + "angle": 0, + "content": "4.1. Tasks" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.778, + 0.892, + 0.823 + ], + "angle": 0, + "content": "We now introduce the tasks used in our experiments (pictured in Fig. 3), and provide more details on their train and test conditions:" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Pushing For this task (see Fig. 3a) the robot must approach a novel object placed on the table and push it to the goal location (marked by target printout). Training: Our method was trained on a dataset of" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.925, + 0.516, + 0.937 + ], + "angle": 0, + "content": "3862" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.085, + 0.089, + 0.282, + 0.204 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.144, + 0.214, + 0.224, + 0.228 + ], + "angle": 0, + "content": "(a) Pushing" + }, + { + "type": "image", + "bbox": [ + 0.284, + 0.089, + 0.481, + 0.204 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.321, + 0.214, + 0.446, + 0.227 + ], + "angle": 0, + "content": "(b) Pick and Place" + }, + { + "type": "image", + "bbox": [ + 0.483, + 0.089, + 0.681, + 0.204 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.524, + 0.214, + 0.643, + 0.228 + ], + "angle": 0, + "content": "(c) Door Opening" + }, + { + "type": "image", + "bbox": [ + 0.683, + 0.089, + 0.882, + 0.204 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.723, + 0.214, + 0.843, + 0.228 + ], + "angle": 0, + "content": "(d) Knob Turning" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.236, + 0.893, + 0.281 + ], + "angle": 0, + "content": "Figure 3: Our method is tested on 4 different manipulation tasks (pictured above). These tasks test different skill axis, ranging from task-level reasoning (e.g. detect target, move to object before goal, etc.) to fine-grained motor control (e.g. grab top of knob to turn)." + }, + { + "type": "image_caption", + "bbox": [ + 0.096, + 0.31, + 0.453, + 0.325 + ], + "angle": 0, + "content": "Low-Cost Human Videos Transferred to Robot" + }, + { + "type": "image", + "bbox": [ + 0.079, + 0.328, + 0.471, + 0.468 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.479, + 0.47, + 0.571 + ], + "angle": 0, + "content": "Figure 4: In our problem setting we use a low-cost reacher grabber tool (left) to collect training demonstrations. These demonstrations are used to acquire a robot controller purely through distance/representation learning. The final system is deployed on a robot (right) to solve various tasks at test-time." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.597, + 0.47, + 0.704 + ], + "angle": 0, + "content": "100 demonstrations with diverse objects and randomized targets. Testing: During test time, the method was evaluated using 20 trails that involved unseen objects and new target printouts placed in randomly sampled positions. A trail is deemed successful if the robot pushes the object onto the target. This is the only task that did not require gripper control." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Pick and Place This task (see Fig. 3b) is analogous to the pushing task (described above), except the robot must now pick the object up from its initial location and place it in a target bowl. This task requires more precision than pushing, since grasping an object is harder than localizing it. Training: We collect a dataset of 400 demonstrations for training, using randomized train objects and target bowls. Testing: The method is evaluated using 20 trails that used novel objects and unseen target bowls (i.e. analogous to pushing). A trail is successful if the robot places an object into the target." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.305, + 0.895, + 0.503 + ], + "angle": 0, + "content": "Door Opening The opening task (see Fig. 3c) requires the robot to approach a handle, grasp it, and then pull the door open. While conceptually simple, this task requires a great deal of precision, since the commanded actions must (almost) exactly match the direction of the door hinge. Training: We created a toy kitchen setting for this task, and collected 100 demonstrations of opening the door when starting from various initial positions. Testing: We evaluated on 20 real world test trials, where the robot's initial position and the door's initial state (e.g. position and hinge angle) were randomized. A trial was deemed successful if the door is opened fully." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.52, + 0.895, + 0.687 + ], + "angle": 0, + "content": "Knob Turning In this final task (see Fig. 3d) the robot must approach a knob in the toy kitchen, and then turn it clock-wise. Similar to the opening task, knob turning requires very precise motor control, since the robot must grab the knob at exactly the right location and carefully rotate in order to turn. Training: We collect a dataset of 100 knob turning demonstrations. Testing: The method is evaluated on 20 trials, with randomized robot/knob initial positions. Success is determined by if the knob is turned far enough to cause an audible \"click.\"" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.697, + 0.748, + 0.711 + ], + "angle": 0, + "content": "4.2. Robot-Free Data Collection" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.894, + 0.903 + ], + "angle": 0, + "content": "A major strength of our setup is that training data \\((\\mathcal{D})\\) can come from a different agent than the test time robot. We leverage this property to collect videos directly from humans operating a low-cost grabber stick (see Fig. 4, left), and use structure from motion [38] to recover actions. This allows us to collect demonstrations without an expensive tele-op setup [50, 23] or time-intensive kinesthetic demonstrations (i.e. manually moving the robot by hand). While based on prior work, our stick setup makes two important contributions: it is easier build and use than the highly instrumented setup in Song et. al. [42], and it provides higher" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.925, + 0.516, + 0.937 + ], + "angle": 0, + "content": "3863" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.086, + 0.088, + 0.895, + 0.65 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.659, + 0.895, + 0.722 + ], + "angle": 0, + "content": "Figure 5: Trajectories executed on the robot using our learned distance function. For each task, we show the \\(1^{st}\\) person view (top) and \\(3^{rd}\\) person view images (bottom). We show the learned visual embedding can encode functional distances between states for challenging tasks, like pushing, pick and place, door opening, and knob turning." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.747, + 0.471, + 0.81 + ], + "angle": 0, + "content": "quality images and action labels than the GoPro used in Young et. al. [48]. Please refer to Supplement A.2 for more information on our training and testing setups. We will release our dataset publicly." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.828, + 0.229, + 0.846 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.471, + 0.903 + ], + "angle": 0, + "content": "The following experiments seek to validate our distance learning framework on real control tasks (described above), and give some fundamental insights" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.747, + 0.895, + 0.868 + ], + "angle": 0, + "content": "as to why they work. First, our baseline study (see Sec. 5.1) compares our method against representative SOTA techniques in the field. In addition, in Sec. 5.2 we analyze a specific scenario with highly multi-modal actions, where our model especially shines. Finally, the ablation study (see Sec. 5.3) investigates which components of our system are actually needed for good performance." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.925, + 0.516, + 0.937 + ], + "angle": 0, + "content": "3864" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.08, + 0.09, + 0.464, + 0.168 + ], + "angle": 0, + "content": "
TaskOursBC [35, 48]IBC [13]IQL [20]
Pushing85%70%70%65%
Pick and Place60%30%30%45%
Door Opening55%40%45%50%
Knob Turning40%20%20%35%
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.179, + 0.47, + 0.242 + ], + "angle": 0, + "content": "Table 1: We compare success rates for our method versus the baselines on all four manipulation tasks. Our distance learning method outperforms a suite of representative robot learning baselines." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.253, + 0.465, + 0.356 + ], + "angle": 0, + "content": "
# DemosPushingPick and Place
OursBCIBCOursBCIBC
5070%50%40%0%0%0%
10085%70%70%10%10%0%
20090%80%100%20%20%10%
400100%100%100%60%30%30%
600100%100%100%70%50%40%
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.366, + 0.47, + 0.442 + ], + "angle": 0, + "content": "Table 2: We compare our distance learning method versus the behavior cloning baselines (BC [35, 48] and IBC [13]) when trained on varying amounts of data. Distance learning is able to learn faster than the baselines and scale better with data." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.468, + 0.228, + 0.484 + ], + "angle": 0, + "content": "5.1. Baseline Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.491, + 0.47, + 0.658 + ], + "angle": 0, + "content": "We first note that our paper uses only demonstration data and no online data. Therefore, we compare our method against three SOTA baselines - ranging from standard behavior cloning, to energy based modeling, and Offline Reinforcement Learning (RL) - that cover a wide range of prior LfD work. The baseline methods are described briefly below. To make the comparisons fair, we parameterize all neural networks with the same R3M representation backbone used by our method, and tune hyper-parameters for best possible performance. Please check Supplement B.2 for in depth details." + }, + { + "type": "text", + "bbox": [ + 0.094, + 0.669, + 0.47, + 0.761 + ], + "angle": 0, + "content": "- Behavior Cloning [35, 48] (BC): BC learns a policy (via regression) that directly predicts actions from image observations: \\(\\min_{\\pi}||\\pi(I_t,I_g) - a_t||_2\\). This provides a strong comparison point for a whole class of LfD methods that focus on learning motor policies directly." + }, + { + "type": "text", + "bbox": [ + 0.094, + 0.77, + 0.47, + 0.877 + ], + "angle": 0, + "content": "- Implicit Behavior Cloning [13] (IBC): IBC learns an energy based model that can predict actions during test time via optimization: \\( a_{t} = \\operatorname{argmin}_{a} E(a, I_{t}, I_{g}) \\). This method is conceptually very similar to behavior cloning, but has the potential to better handle multi-modal action distributions and discontinuous actions." + }, + { + "type": "text", + "bbox": [ + 0.094, + 0.885, + 0.47, + 0.903 + ], + "angle": 0, + "content": "- Implicit Q-Learning [20] (IQL): IQL is an" + }, + { + "type": "list", + "bbox": [ + 0.094, + 0.669, + 0.47, + 0.903 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.531, + 0.091, + 0.892, + 0.228 + ], + "angle": 0, + "content": "offline-RL baseline that learns a Q function \\(Q(s,a) = Q((I_t,I_g),a_t)\\), alongside a policy that maximizes it \\(\\pi (I_t,I_g) = \\arg \\max_aQ(s,a)\\). Note that IQL's training process requires us to annotate our offline trajectories \\(\\mathcal{D}\\) with a reward signal \\(r_t\\) for each time-step. While this can be done automatically in our setting (Supplement B.2), this is an additional assumption that could be very burdensome in the general case." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.235, + 0.895, + 0.388 + ], + "angle": 0, + "content": "Our method is compared against the baselines on all four of our tasks (see Sec. 4.1). Results are reported in Table 1. Note how our distance learning approach achieves the highest success rates on all of four tasks. In addition, our method is much simpler than the strongest baseline (IQL), which requires an expert defined reward signal and uses a more complicated learning algorithm. The final test time performance is visualized in Fig. 5 and on our website: https://agilabs.github.io/manipulate-by-seeing/." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.402, + 0.895, + 0.569 + ], + "angle": 0, + "content": "Data Scaling A common cited strength of BC (versus RL) is its ability to continuously improve with additional expert data. Can our method do the same? Table 2 compares our distance learning method versus the BC/IBC baselines (on pushing/pick-place tasks), when trained on various amounts of data. Note how our method both learns faster than BC/IBC, and continuously scales with added demonstrations. This suggests that distance learning is a powerful alternative to BC on robotic manipulation tasks, no matter how much training data is available." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.576, + 0.753, + 0.592 + ], + "angle": 0, + "content": "5.2. Multi-Modality Experiment" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.599, + 0.892, + 0.901 + ], + "angle": 0, + "content": "A common challenge in policy learning is effectively handling multi-modal action predictions. We propose a simple test scenario that allows us to test our method in this setting without any other confounding variables. Specifically, we create a \"obstacle pushing\" task where the robot must push an object to the target without disturbing an obstacle placed in the middle (see Fig. 6). Observe that there are two equally valid ways that the robot could push the block; to the left or to the right. We collect a training dataset of 100 demos, equally split between going left and right. This creates action multi-modality where the agent must arbitrarily choose between two scenarios in order to successfully perform the task, but will fail if it simply averages the actions and pushes the block forward (into the obstacle). We expect that standard BC will fall into this failure mode, since it is trained using standard L2 action regression. In contrast, our method should still work since the low distance states will move the robot either to the left or right state, thus allowing it to make a discrete choice." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.925, + 0.516, + 0.937 + ], + "angle": 0, + "content": "3865" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.119, + 0.09, + 0.428, + 0.329 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.34, + 0.47, + 0.432 + ], + "angle": 0, + "content": "Figure 6: Our method can solve tasks with highly multi-modal action distributions that are difficult for the baselines. In this example, our distance learning controller successfully pushes the block around the obstacle, while Behavior Cloning learns to incorrectly push the block forward (i.e. predicts mean action)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.459, + 0.47, + 0.669 + ], + "angle": 0, + "content": "To verify this hypothesis, we test our method, the BC baseline, and IQL (the strongest non-BC baseline) on 20 trials in this task setting. Success is judged similarly as to pushing (see Sec. 4.1), with the added condition that the robot should not push the obstacles into the target. Our method achieves a \\(95\\%\\) success rate, versus \\(0\\%\\) for BC and \\(90\\%\\) for IQL in this setting! As expected, our method is able to greatly improve upon BC in this setting, because it explicitly avoids action prediction. While IQL should not suffer as badly from multi-modality, thanks to its learned value function, our method is still able to outperform it despite being simpler algorithmically and trained without reward signal." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.681, + 0.229, + 0.697 + ], + "angle": 0, + "content": "5.3. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.705, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Our final experiment removes components of our method in order to determine which parts were most crucial for control performance. The representation ablation replaces the R3M backbone in our neural network with a pre-trained ImageNet representation (using same ResNet-18 architecture for both). We expect the ImageNet weights to be weaker, since they were trained on a smaller dataset that did not include egocentric videos (ImageNet vs Ego4D used by R3M). Additionally, the dynamics ablation removes the dynamics module during training, thus leaving the distance model/embeddings without any physical grounding. This is similar to the method from Hahn et. al. [15] (see" + }, + { + "type": "table", + "bbox": [ + 0.503, + 0.09, + 0.887, + 0.164 + ], + "angle": 0, + "content": "
OursImageNet Repr.No Dynamics [15]
Pushing90%40%60%
Pick and Place60%40%35%
Door Opening55%45%50%
Knob Turning40%15%40%
" + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.176, + 0.892, + 0.251 + ], + "angle": 0, + "content": "Table 3: This table compares success rates for our method versus the ablations on the all four tasks. As you can see, removing the dynamics module from our method during training and training with a weaker representation both result in worse performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.279, + 0.892, + 0.34 + ], + "angle": 0, + "content": "Sec. 2), with an added dynamics module. We expect this ablation to perform worse on manipulation tasks, because dynamics is more important in this setting v.s. visual navigation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.34, + 0.892, + 0.506 + ], + "angle": 0, + "content": "The two ablations are evaluated and compared against our method on all four test tasks (see Table 3). We find that our method strongly outperforms both of our baselines, which suggests that our intuition outline above is correct. In particular, we conclude that stronger representations can directly stronger control performance using our method. Additionally, this shows that the dynamics grounding is important to ensure that our learned distances transfer onto real robot hardware during test time, especially in manipulation tasks that involve object interactions/contact." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.522, + 0.63, + 0.538 + ], + "angle": 0, + "content": "6. Discussion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.548, + 0.892, + 0.805 + ], + "angle": 0, + "content": "This paper demonstrates that neural image representations can be more than just state representations: a simple metric defined within the embedding space can help infer robot actions. We leverage this insight to learn a distance function and dynamics function using minimal low-cost human data. These modules parameterize a robotic planner that is validated across 4 representative manipulation tasks. Despite its simplicity, our method is able to outperform standard imitation learning and offline-RL methods in the robot learning field. This is especially true in situations involving multi-modal action distributions, where our method entirely outclasses a standard BC baseline. Finally, the ablation study demonstrates that stronger representations directly result in stronger control performance, and that dynamics grounding is important for our scheme to work in practice." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Future Work We hope that this paper inspires future work in the space of representation learning and robotics. Follow up works should improve visual representations specifically for robotics, by more precisely capturing fine-grained interactions between gripper/-" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.925, + 0.516, + 0.937 + ], + "angle": 0, + "content": "3866" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.288 + ], + "angle": 0, + "content": "hand and objects. This could improve performance on tasks like knob turning, where the pre-trained R3M encoder often struggled to detect small shifts of the gripper relative to the knob. We also hope that our contrastive learning method could be extended to learn entirely without action labels. This would allow us to train on large scale manipulation datasets (e.g. YouTube videos) and transfer the results directly to the control setting. Finally, it would be ideal if data collected using our low-cost stick (see Fig. 4) could be used with a stronger, more reliable (commercial) gripper, despite the domain gap. This would enable us to solve more tasks during test time." + }, + { + "type": "title", + "bbox": [ + 0.079, + 0.304, + 0.186, + 0.319 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.329, + 0.47, + 0.385 + ], + "angle": 0, + "content": "[1] Pieter Abbeel and Andrew Y Ng. Apprenticeship learning via inverse reinforcement learning. In Proceedings of the twenty-first international conference on Machine learning, page 1, 2004." + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.387, + 0.472, + 0.47 + ], + "angle": 0, + "content": "[2] OpenAI: Marcin Andrychowicz, Bowen Baker, Maciek Chociej, Rafal Jozefowicz, Bob McGrew, Jakub Pachocki, Arthur Petron, Matthias Plappert, Glenn Powell, Alex Ray, et al. Learning dexterous in-hand manipulation. The International Journal of Robotics Research, 39(1):3-20, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.089, + 0.472, + 0.472, + 0.527 + ], + "angle": 0, + "content": "[3] Daniel Angelov, Yordan Hristov, Michael Burke, and Subramanian Ramamoorthy. Composing diverse policies for temporally extended tasks. IEEE Robotics and Automation Letters, 5(2):2658-2665, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.089, + 0.529, + 0.47, + 0.584 + ], + "angle": 0, + "content": "[4] Brenna D Argall, Sonia Chernova, Manuela Veloso, and Brett Browning. A survey of robot learning from demonstration. Robotics and autonomous systems, 57(5):469-483, 2009." + }, + { + "type": "ref_text", + "bbox": [ + 0.089, + 0.586, + 0.47, + 0.642 + ], + "angle": 0, + "content": "[5] Yusuf Aytar, Tobias Pfaff, David Budden, Thomas Paine, Ziyu Wang, and Nando De Freitas. Playing hard exploration games by watching youtube. Advances in neural information processing systems, 31, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.089, + 0.644, + 0.468, + 0.672 + ], + "angle": 0, + "content": "[6] Shikhar Bahl, Abhinav Gupta, and Deepak Pathak. Human-to-robot imitation in the wild. RSS, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.089, + 0.673, + 0.468, + 0.729 + ], + "angle": 0, + "content": "[7] Aude Billard, Sylvain Calinon, Ruediger Dillmann, and Stefan Schaal. Survey: Robot programming by demonstration. Handbook of robotics, 59(BOOK_CHAP), 2008." + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.731, + 0.468, + 0.785 + ], + "angle": 0, + "content": "[8] Annie S Chen, Suraj Nair, and Chelsea Finn. Learning generalizable robotic reward functions from\" in-the-wild\" human videos. arXiv preprint arXiv:2103.16817, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.788, + 0.468, + 0.87 + ], + "angle": 0, + "content": "[9] Lili Chen, Kevin Lu, Aravind Rajeswaran, Kimin Lee, Aditya Grover, Misha Laskin, Pieter Abbeel, Aravind Srinivas, and Igor Mordatch. Decision transformer: Reinforcement learning via sequence modeling. Advances in neural information processing systems, 34:15084-15097, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.468, + 0.901 + ], + "angle": 0, + "content": "[10] Sudeep Dasari and Abhinav Gupta. Transformers for one-shot imitation learning. In CoRL 2020, 2020." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.329, + 0.472, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "[11] Sudeep Dasari, Abhinav Gupta, and Vikash Kumar. Learning dexterous manipulation from exemplar object trajectories and pre-grasps. In IEEE International Conference on Robotics and Automation 2023, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.15, + 0.892, + 0.219 + ], + "angle": 0, + "content": "[12] Sudeep Dasari, Jianren Wang, Joyce Hong, Shikhar Bahl, Yixin Lin, Austin Wang, Abitha Thankaraj, Karanbir Chahal, Berk Calli, Saurabh Gupta, et al. Rb2: Robotic manipulation benchmarking with a twist. arXiv preprint arXiv:2203.08098, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.221, + 0.892, + 0.29 + ], + "angle": 0, + "content": "[13] Pete Florence, Corey Lynch, Andy Zeng, Oscar Ramirez, Ayzaan Wahid, Laura Downs, Adrian Wong, Johnny Lee, Igor Mordatch, and Jonathan Tompson. Implicit behavioral cloning. Conference on Robot Learning (CoRL), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.292, + 0.892, + 0.387 + ], + "angle": 0, + "content": "[14] Kristen Grauman, Andrew Westbury, Eugene Byrne, Zachary Chavis, Antonino Furnari, Rohit Girdhar, Jackson Hamburger, Hao Jiang, Miao Liu, Xingyu Liu, et al. Ego4d: Around the world in 3,000 hours of egocentric video. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18995-19012, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.39, + 0.892, + 0.459 + ], + "angle": 0, + "content": "[15] Meera Hahn, Devendra Singh Chaplot, Shubham Tulsiani, Mustafa Mukadam, James M Rehg, and Abhinav Gupta. No rl, no simulation: Learning to navigate without navigating. Advances in Neural Information Processing Systems, 34:26661-26673, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.461, + 0.892, + 0.558 + ], + "angle": 0, + "content": "[16] Ankur Handa, Arthur Allshire, Viktor Makoviychuk, Aleksei Petrenko, Ritvik Singh, Jingzhou Liu, Denys Makoviichuk, Karl Van Wyk, Alexander Zhurkevich, Balakumar Sundaralingam, Yashraj Narang, Jean-Francois Lafleche, Dieter Fox, and Gavriel State. Dextreme: Transfer of agile in-hand manipulation from simulation to reality. arXiv, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.56, + 0.892, + 0.615 + ], + "angle": 0, + "content": "[17] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.616, + 0.892, + 0.685 + ], + "angle": 0, + "content": "[18] Eric Jang, Alex Irpan, Mohi Khansari, Daniel Kappler, Frederik Ebert, Corey Lynch, Sergey Levine, and Chelsea Finn. Bc-z: Zero-shot task generalization with robotic imitation learning. In Conference on Robot Learning, pages 991-1002. PMLR, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.687, + 0.892, + 0.728 + ], + "angle": 0, + "content": "[19] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.73, + 0.892, + 0.771 + ], + "angle": 0, + "content": "[20] Ilya Kostrikov, Ashvin Nair, and Sergey Levine. Offline reinforcement learning with implicit q-learning. arXiv preprint arXiv:2110.06169, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.773, + 0.892, + 0.829 + ], + "angle": 0, + "content": "[21] Aviral Kumar, Rishabh Agarwal, Dibya Ghosh, and Sergey Levine. Implicit under-parameterization inhibits data-efficient deep reinforcement learning. arXiv preprint arXiv:2010.14498, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.831, + 0.892, + 0.871 + ], + "angle": 0, + "content": "[22] Ashish Kumar, Zipeng Fu, Deepak Pathak, and Jitendra Malik. Rma: Rapid motor adaptation for legged robots. arXiv preprint arXiv:2107.04034, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.873, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[23] Vikash Kumar and Emanuel Todorov. Mujoco haptix: A virtual reality system for hand manipulation. In" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.926, + 0.516, + 0.937 + ], + "angle": 0, + "content": "3867" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.133 + ], + "angle": 0, + "content": "Humanoid Robots (Humanoids), 2015 IEEE-RAS 15th International Conference on, pages 657-663. IEEE, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.134, + 0.47, + 0.189 + ], + "angle": 0, + "content": "[24] Joonho Lee, Jemin Hwangbo, Lorenz Wellhausen, Vladlen Koltun, and Marco Hutter. Learning quadrupedal locomotion over challenging terrain. Science robotics, 5(47):eabc5986, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.19, + 0.471, + 0.245 + ], + "angle": 0, + "content": "[25] Sergey Levine, Aviral Kumar, George Tucker, and Justin Fu. Offline reinforcement learning: Tutorial, review, and perspectives on open problems. arXiv preprint arXiv:2005.01643, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.246, + 0.471, + 0.288 + ], + "angle": 0, + "content": "[26] Yixin Lin and Austin Wang. Polymetis: a real-time pytorch controller manager. In https://github.com/facebookresearch/polymetis, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.289, + 0.471, + 0.343 + ], + "angle": 0, + "content": "[27] Corey Lynch, Mohi Khansari, Ted Xiao, Vikash Kumar, Jonathan Tompson, Sergey Levine, and Pierre Sermanet. Learning latent plans from play. In Conference on robot learning, pages 1113-1132. PMLR, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.344, + 0.471, + 0.399 + ], + "angle": 0, + "content": "[28] Andriy Mnih and Koray Kavukcuoglu. Learning word embeddings efficiently with noise-contrastive estimation. Advances in neural information processing systems, 26, 2013." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.4, + 0.471, + 0.453 + ], + "angle": 0, + "content": "[29] Suraj Nair, Aravind Rajeswaran, Vikash Kumar, Chelsea Finn, and Abhinav Gupta. R3m: A universal visual representation for robot manipulation. CoRL, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.455, + 0.471, + 0.496 + ], + "angle": 0, + "content": "[30] Aaron van den Oord, Yazhe Li, and Oriol Vinyals. Representation learning with contrastive predictive coding. arXiv preprint arXiv:1807.03748, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.497, + 0.471, + 0.552 + ], + "angle": 0, + "content": "[31] Simone Parisi, Aravind Rajeswaran, Senthil Purushwalkam, and Abhinav Gupta. The unsurprising effectiveness of pre-trained vision models for control. arXiv preprint arXiv:2203.03580, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.553, + 0.471, + 0.607 + ], + "angle": 0, + "content": "[32] Ilija Radosavovic, Tete Xiao, Stephen James, Pieter Abbeel, Jitendra Malik, and Trevor Darrell. Realworld robot learning with masked visual pre-training. CoRL, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.609, + 0.471, + 0.69 + ], + "angle": 0, + "content": "[33] Aravind Rajeswaran, Vikash Kumar, Abhishek Gupta, Giulia Vezzani, John Schulman, Emanuel Todorov, and Sergey Levine. Learning complex dexterous manipulation with deep reinforcement learning and demonstrations. arXiv preprint arXiv:1709.10087, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.692, + 0.471, + 0.746 + ], + "angle": 0, + "content": "[34] Frank Rosenblatt. Principles of neurodynamics. perceptrons and the theory of brain mechanisms. Technical report, Cornell Aeronautical Lab Inc Buffalo NY, 1961." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.748, + 0.471, + 0.816 + ], + "angle": 0, + "content": "[35] Stéphane Ross, Geoffrey Gordon, and Drew Bagnell. A reduction of imitation learning and structured prediction to no-regret online learning. In Proceedings of the fourteenth international conference on artificial intelligence and statistics, pages 627-635, 2011." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.818, + 0.471, + 0.858 + ], + "angle": 0, + "content": "[36] Stefan Schaal. Is imitation learning the route to humanoid robots? Trends in cognitive sciences, 3(6):233-242, 1999." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.859, + 0.471, + 0.901 + ], + "angle": 0, + "content": "[37] Karl Schmeckpeper, Oleh Rybkin, Kostas Daniilidis, Sergey Levine, and Chelsea Finn. Reinforcement learning with videos: Combining offline observations with" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "interaction. In Conference on Robot Learning, pages 339-354. PMLR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.122, + 0.892, + 0.176 + ], + "angle": 0, + "content": "[38] Johannes Lutz Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In Conference on Computer Vision and Pattern Recognition (CVPR), 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.179, + 0.892, + 0.261 + ], + "angle": 0, + "content": "[39] Pierre Sermanet, Corey Lynch, Yevgen Chebotar, Jasmine Hsu, Eric Jang, Stefan Schaal, Sergey Levine, and Google Brain. Time-contrastive networks: Self-supervised learning from video. In 2018 IEEE international conference on robotics and automation (ICRA), pages 1134–1141. IEEE, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.262, + 0.892, + 0.304 + ], + "angle": 0, + "content": "[40] Pierre Sermanet, Kelvin Xu, and Sergey Levine. Unsupervised perceptual rewards for imitation learning. arXiv preprint arXiv:1612.06699, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.305, + 0.892, + 0.374 + ], + "angle": 0, + "content": "[41] Nur Muhammad Mahi Shafiullah, Zichen Jeff Cui, Ariuntuya Altanzaya, and Lerrel Pinto. Behavior transformers: Cloning \\(k\\) modes with one stone. In Thirty-Sixth Conference on Neural Information Processing Systems, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.375, + 0.892, + 0.431 + ], + "angle": 0, + "content": "[42] Shuran Song, Andy Zeng, Johnny Lee, and Thomas Funkhouser. Grasping in the wild: Learning 6 dof closed-loop grasping from low-cost demonstrations. Robotics and Automation Letters, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.432, + 0.892, + 0.46 + ], + "angle": 0, + "content": "[43] Richard S Sutton and Andrew G Barto. Reinforcement learning: An introduction. MIT press, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.461, + 0.892, + 0.503 + ], + "angle": 0, + "content": "[44] Michita Imai Takuma Seno. d3rlpy: An offline deep reinforcement library. In NeurIPS 2021 Offline Reinforcement Learning Workshop, December 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.504, + 0.892, + 0.56 + ], + "angle": 0, + "content": "[45] Emanuel Todorov, Tom Erez, and Yuval Tassa. Mu-joco: A physics engine for model-based control. In 2012 IEEE/RSJ international conference on intelligent robots and systems, pages 5026-5033. IEEE, 2012." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.56, + 0.892, + 0.602 + ], + "angle": 0, + "content": "[46] Faraz Torabi, Garrett Warnell, and Peter Stone. Generative adversarial imitation from observation. arXiv preprint arXiv:1807.06158, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.603, + 0.892, + 0.658 + ], + "angle": 0, + "content": "[47] Annie Xie, Avi Singh, Sergey Levine, and Chelsea Finn. Few-shot goal inference for visuomotor learning and planning. In Conference on Robot Learning, pages 40-52. PMLR, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.66, + 0.892, + 0.715 + ], + "angle": 0, + "content": "[48] Sarah Young, Dhiraj Gandhi, Shubham Tulsiani, Abhinav Gupta, Pieter Abbeel, and Lerrel Pinto. Visual imitation made easy. In Conference on Robot Learning, pages 1992-2005. PMLR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.716, + 0.892, + 0.786 + ], + "angle": 0, + "content": "[49] Tianhe Yu, Deirdre Quillen, Zhanpeng He, Ryan Julian, Karol Hausman, Chelsea Finn, and Sergey Levine. Meta-world: A benchmark and evaluation for multi-task and meta reinforcement learning. In _Conference on Robot Learning (CoRL)_, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.786, + 0.892, + 0.87 + ], + "angle": 0, + "content": "[50] Tianhao Zhang, Zoe McCarthy, Owen Jow, Dennis Lee, Xi Chen, Ken Goldberg, and Pieter Abbeel. Deep imitation learning for complex manipulation tasks from virtual reality teleoperation. In 2018 IEEE International Conference on Robotics and Automation (ICRA), pages 5628-5635. IEEE, 2018." + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.87 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.926, + 0.516, + 0.937 + ], + "angle": 0, + "content": "3868" + } + ] +] \ No newline at end of file diff --git a/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/4fa47878-d18c-4c5d-89a6-b50ae3093aaf_origin.pdf b/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/4fa47878-d18c-4c5d-89a6-b50ae3093aaf_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..c65bb3abf61dc7315fdf6d5ad821f24153b8346d --- /dev/null +++ b/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/4fa47878-d18c-4c5d-89a6-b50ae3093aaf_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:83baa7a9f6a47990e57156f98c7f276837488dc43dc2731f16327a118dbcdcbf +size 740295 diff --git a/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/full.md b/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/full.md new file mode 100644 index 0000000000000000000000000000000000000000..499c8fbd803002c3e996c1ae643ebd64f0b89cc8 --- /dev/null +++ b/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/full.md @@ -0,0 +1,246 @@ +# Manipulate by Seeing: Creating Manipulation Controllers from Pre-Trained Representations + +Jianren Wang* Sudeep Dasari* Mohan Kumar Srirama Shubham Tulsiani Abhinav Gupta + +Carnegie Mellon University + +# Abstract + +The field of visual representation learning has seen explosive growth in the past years, but its benefits in robotics have been surprisingly limited so far. Prior work uses generic visual representations as a basis to learn (task-specific) robot action policies (e.g., via behavior cloning). While the visual representations do accelerate learning, they are primarily used to encode visual observations. Thus, action information has to be derived purely from robot data, which is expensive to collect! In this work, we present a scalable alternative where the visual representations can help directly infer robot actions. We observe that vision encoders express relationships between image observations as distances (e.g., via embedding dot product) that could be used to efficiently plan robot behavior. We operationalize this insight and develop a simple algorithm for acquiring a distance function and dynamics predictor, by finetuning a pre-trained representation on human collected video sequences. The final method is able to substantially outperform traditional robot learning baselines (e.g., $70\%$ success v.s. $50\%$ for behavior cloning on pick-place) on a suite of diverse real-world manipulation tasks. It can also generalize to novel objects, without using any robot demonstrations during train time. For visualizations of the learned policies please check: https://agi-labs.github.io/manipulate-by-seeing/. + +# 1. Introduction + +The lack of suitable, large-scale data-sets is a major bottleneck in robot learning. Due to the physical nature of data collection, robotics data-sets are: (a) hard to scale; (b) collected in sterile, non-realistic environments (e.g. robotics lab); (c) too homogeneous (e.g. toy objects with fixed backgrounds/lighting). In contrast, vision data-sets contain diverse tasks, objects, + +![](images/6539cafe82d4a0cd000cfd89ebcd050b34681416a30c0dabc063f42b2c8cb00b.jpg) +Figure 1: This paper proposes to solve a range of manipulation tasks (e.g. pushing) by learning a functional distance metric within the embedding space of a pretrained network. This distance function - in combination with a learned dynamics model - can be used to greedily plan for robot actions that reach a goal state. Our experiments reveal that the proposed method can outperform SOTA robot learning methods across four diverse manipulation tasks. + +and settings (e.g. Ego4D [14]). Therefore, recent approaches have explored transferring priors from large scale vision data-sets to robotics settings. What is the right way to accomplish this? + +Prior work uses vision data-sets to pre-train representations [31, 29, 32] that encode image observations as state vectors (i.e. $s = R(i)$ ). This visual representation is then simply used as an input for a controller learned from robot data - e.g. a policy $\pi(a|s)$ , trained with expert data via Behavior Cloning [35], or a Value function $V(s)$ , trained using exploratory roll-outs via Reinforcement Learning [43]. Is this approach the most efficient way to use pre-trained representations? We argue that pre-trained networks can do more than just represent states, since their latent space already encodes semantic, task-level information - e.g. by plac + +ing semantically similar states more closely together. Leveraging this structure to infer actions, could enable us to use significantly less robotic data during train time. + +Our paper achieves this by fine-tuning a pre-trained representation into: (a) a one-step dynamics module, $F(s,a)$ , that predicts how the robot's next state given the current state/action; and (b) a "functional distance module", $d(s,g)$ , that calculates how close the robot is to achieving its goal $g$ in the state $s$ . The distance function is learned with limited human demonstration data, using a contrastive learning objective (see Fig. 2). Both $d$ and $F$ are used in conjunction to greedily plan robot actions (see Fig. 1 for intuition). Our experiments demonstrate that this approach works better than policy learning (via Behavior Cloning), because the pre-trained representation itself does the heavy lifting (thanks to its structure) and we entirely dodge the challenge of multi-modal, sequential action prediction. Furthermore, our learned distance function is both stable and easy to train, which allows it to easily scale and generalize to new scenarios. + +To summarize, we show a simple approach for exploiting the information hidden in pre-trained visual representations. Our contributions include: + +- Developing a simple algorithm for acquiring a distance function and dynamics model by fine-tuning a pre-trained visual representation on minimal (human collected) data. +- Creating an effective manipulation controller that substantially outperforms State-of-the-Art (SOTA) prior methods from the robot learning community (e.g. Behavior Cloning [35], Offline-RL [20], etc.). +- Demonstrating that our approach can handle four realistic manipulation tasks, generalize to new objects and settings, and solve challenging scenarios w/ multi-modal action distributions. + +# 2. Related Work + +Behavior Cloning This paper adopts the Learning from Demonstration (LfD) problem setting [4, 7, 36], where a robot must acquire manipulation behaviors given expert demonstration trajectories. A standard approach in this space is to learn a policy $(\pi)$ via Behavior Cloning [35] (BC), which directly optimizes $\pi$ to match the expert's action distribution. While conceptually simple, realistic action distributions are difficult to model, since they are inherently multi-modal and even small errors compound over time. Thus, policy + +learning requires extensive intensive network engineering (e.g. transformer architectures [10, 9], multi-modal prediction heads [41, 27], etc.) and/or human-in-the-loop data collection algorithms [35, 18] to work in practice. Instead of learning a policy, we learn a functional distance metric that captures the how “close” a state is to reaching a target goal. This lets us build a manipulation controller using a simple greedy planner during test time, without any explicit action prediction! + +Offline RL Broadly speaking, the field of Reinforcement Learning [43] (RL) seeks to learn a value/advantage/Q function by assuming access to a reward signal, which "evaluates" a state (e.g. $+1$ reward for reaching goal). RL algorithms usually require environment interaction to learn, though the field of Offline-RL [25] seeks to extend these systems to learn from offline trajectories. While these approaches have created some impressive robotics demos ranging from locomotion [24, 22] to dexterous manipulation [2, 16, 11], RL methods are data hungry [33, 2], difficult to implement, require extreme "reward engineering" (e.g. MetaWorld [49] reward functions are 50 lines!), hampered by unstable learning dynamics [21], and poorly generalize in realistic robotic manipulation settings [12]. In contrast, our method learns a proxy for value functions (i.e. distances) purely from offline data, using representation learning algorithms (from the vision field) that are much more stable. + +Learning Visual Rewards Our distance learning approach is analogous to learning visual rewards. Prior work learned success classifiers [40, 47, 46] and/or video similarity metrics [39, 5, 37, 6, 8] from expert video demonstrations. Once learned, these modules were used to parameterize reward functions that could be used to train policies [1], and/or as cost functions for planners [3]. However, these papers mostly consider simple settings (e.g. simulation) or require the test setting to exactly match train time. This is because the learned reward functions are often noisy and/or poorly generalize to new scenes. In contrast, our learned distance metric is stable and can easily adapt to new scenarios, thanks to the pre-trained network's latent structure. This allows us to solve diverse tasks during test time on a real robot, using a simple (and fast) shooting method planner. + +Distance Learning for Navigation Finally, prior work from Hahn et. al. [15] explored distance learning to solve visual navigation tasks from offline video data. Our work is inspired from this approach, but makes + +three key innovations in order to apply it to (more challenging) robotic manipulation tasks. First, we simplify the network architecture to operate in representation space instead of using a graph network. Second, we learn the distances using a self-supervised contrastive loss, instead of relying on hand-defined objectives. And third, we add a dynamics function that proves to be critical for effective manipulation (see Table. 3). + +# 3. Methods + +Preliminaries This paper considers learning goal-conditioned manipulation behaviors from image observations. The robot agent is provided a goal observation $(I_g) - \mathrm{e.g.}$ target object in robot gripper - and an observation $(I_t)$ for the current time-step $t$ . The robot must process these observations and decide an action to take $(a_{t})$ . Note that all observations $(I)$ are wrist-mounted RGB camera images with no depth or proprioceptive data. Additionally, the actions $(a)$ are specified as arbitrary $SE(3)$ transforms for the robot's end-effector (more in Supplement B.1). Our goal is to learn a robotic manipulation controller, using a set of training trajectories $\mathcal{D} = \{\tau_1,\dots ,\tau_N\}$ , where $\tau_{i} = \{I_{g},I_{1},a_{1},\ldots ,a_{T - 1},I_{T}\}$ . The test and train settings are visualized in Fig. 4. + +Our Approach Our method leverages a pre-trained representation network, $R$ , to encode observations, $i_{t} = R(I_{t})$ , and enable control via distance learning. Specifically, we use contrastive representation learning methods [30, 28] to learn a distance metric, $d(i_j,i_k)$ within the pre-trained embedding space. The key idea is to use this distance metric to select which of the possible future state is closest to the goal state. But how do we predict possible future states? We explicitly learn a dynamics function, $F(i_{t},a_{t})$ that predicts future state for a possible action $a_{t}$ . During test time, we predict multiple future states using different possible action and select the one which is closest to goal state. The following sections describe the learned dynamics module (see Sec. 3.1), distance learning method (see Sec. 3.2), and test-time controller for robot deployment (see Sec. 3.4) in detail. Fig. 2 provides a visual depiction of our training algorithm. Pseudo-code and hyper-parameters are presented in Supplement A.3. + +# 3.1. Dynamics Prediction + +An ideal dynamics function would perfectly capture how a robot's actions effects its environment. In our setting, this translates to predicting the next observation embedding, given the current embedding and commanded action: $F(i_{t},a_{t}) = i_{t + 1}$ . Thus, $F$ can + +be learned via regression by minimizing reconstruction loss in embedding space: $\mathcal{L}_F = ||F(i_t,a_t) - i_{t + 1}||_2$ (see Fig. 2, left). This module has two primary uses: (1) during training it acts as a physically grounded regularizer that relays action information into the embedding space, and (2) during test time it enables the robot to plan actions in embedding space. As you will see, both properties are leveraged extensively in the rest of our method. + +# 3.2. Learning Task-Centric Distances + +Our distance module $d(i_j, i_k)$ seeks to learn functional distances that encode task-centric reasoning (e.g. must reach for object before pushing it) alongside important physical priors (e.g. object is to the left so move left). How can we learn such a distance space? Since we have access to expert trajectories $\tau$ , we know that the next state sequentially visited by the expert $(i_{t+1})$ is closer to the goal state $(i_g)$ than arbitrary states $(\hat{i})$ reachable from $i_t$ - i.e. $d(i_{t+1}, i_g) << d(\hat{i}, i_g)$ . + +Our insight is that a distance metric with these properties can be learned via contrastive learning. Specifically, we define $d(i_j,i_k) = -\cos (i_j,i_k)$ , where $\cos$ is cosine similarity, and sample a observation-state-goal tuples $(i_t,a_t,i_g)$ , alongside random noise action candidates $\hat{a}^1,\dots ,\hat{a}^n$ sampled from $\mathcal{D}$ . We apply NCE loss and get: + +$$ +\mathcal {L} _ {d} = \frac {e x p (- d (F (i _ {t} , a _ {t}) , i _ {g}))}{e x p (- d (F (i _ {t} , a _ {t}) , i _ {g})) + \Sigma_ {j} e x p (- d (F (i _ {t} , \hat {a} ^ {j}) , i _ {g}))} +$$ + +This loss creates a warped embedding space where $i_{t+1}$ (hallucinated by $F(i_t, a_t)$ ) is pushed closer towards the goal state $i_g$ , than other arbitrary states reachable from $i_t$ (again hallucinated by $F$ ). This process is shown visually in Fig. 2 (right), and precisely satisfies our criteria for good distance functions. + +# 3.3. Training Details + +Both modules are trained jointly resulting in a final loss: $\mathcal{L} = \lambda_d\mathcal{L}_d + \lambda_F\mathcal{L}_F$ . Note that $F$ is implemented as small neural networks with 2 hidden layers, while $d$ does not require any extra learned networks since its implemented via contrastive loss in the metric space. The shared representation network, $R$ , we use is ResNet-18 initialized by R3M weights. The ADAM [19] stochastic gradient descent optimizer and back-propagation are used to train the network end-to-end. Please refer to Supplement A.3. for additional details. + +# 3.4. Test Time Robot Deployment + +During test time our learned modules must be able to solve real manipulation tasks when deployed on + +![](images/32f761e924347836ca27401d5c09e7df302aec3f4171515ac4a5a774f87e7248.jpg) +Figure 2: We visualize the loss functions used to train our method. The dynamics function is trained via reconstruction loss in embedding space (left). The distance function is trained via contrastive learning, with positive anchors chosen by predicting the next state using the ground truth action, $F(i_{t},a_{t})$ , and predicting negative pairs chosen using noisy actions $F(i_{t},\hat{a}^{j})$ . + +![](images/e72a925803eadf711bbeeaba45553b5648caa668defcebe0c95d8ffda2fdb103.jpg) + +robot hardware. Thus, we develop a simple inference policy that solves for robot actions using our learned distance and dynamics function. First, a cost function $C_g(i) = d(i,i_g)$ is parameterized given a goal observation $I_{g}$ and the learned distance function. $C_g$ encodes how far an arbitrary image observation is from the goal image. The optimal action, $a_{t}^{*}$ , will take the robot closest to the goal, hence: $a_{t}^{*} = \mathbf{argmin}_{a}C_{g}(F(i_{t},a))$ . Note that we use the dynamics function $F$ to predict the next state, since we do not know the real $i_{t + 1}^{*}$ during test time. The cost minimization is performed using the shooting method: random candidate actions, $a_1,\ldots ,a_N$ , are sampled from $\mathcal{D}$ , passed through the dynamics function, and the action with minimum cost $C_g(F(i_t,a_i))$ is executed on the robot. This process is illustrated in Fig. 1. Policy execution ends once the distance between the current state and the goal falls below a threshold value: $C_g(i_t) < \lambda$ . While a more complicated planner could've been used, this solution was adopted due to its speed, simplicity, lack of hyperparameters, and good empirical performance. + +The final detail to discuss is gripper control for prehensile tasks (e.g. pick and place). Since the gripper status is binary (open/close) and highly correlated with the current state (i.e. close when object in hand), it makes more sense to handle it implicitly rather than as part of the action command $a_{t}$ . Thus, we trained a gripper action classifier $\mathcal{G}(i_t)\in [0,1]$ that predicts the probability of closing the gripper given the current + +image embedding. This is also implemented by adding a single layer to ResNet-18 initialized by R3M weights and can be trained using a small amount $(< 100)$ of human labelled images from the train dataset $\mathcal{D}$ . As a result, our system can seamlessly handle gripper control in prehensile tasks, without requiring gripper labels for every frame in $\mathcal{D}$ ! + +# 4. Experimental Setup + +Our method is tested on four different manipulation tasks (see Fig. 3) that require a mix of high-level reasoning (e.g. go to object before target), low level precision (must carefully grab knob to turn it), and time-time generalization (e.g. push novel object). We collect behavior data for each task from human demonstrators as described below. The trained policies are deployed on a real Franka Pandas robot (see Fig. 4, right). Additional details on the hardware setup and control stack are presented in Supplement B.1. + +# 4.1. Tasks + +We now introduce the tasks used in our experiments (pictured in Fig. 3), and provide more details on their train and test conditions: + +Pushing For this task (see Fig. 3a) the robot must approach a novel object placed on the table and push it to the goal location (marked by target printout). Training: Our method was trained on a dataset of + +![](images/35a211cc8cb76b0991a26470b1cd2874927bded007aee8718ee9872a7c06c8ce.jpg) +(a) Pushing + +![](images/47d95f914e85a5422d588c3490040c63cd4d8567afd47eed5d3035afd28fa48c.jpg) +(b) Pick and Place +Figure 3: Our method is tested on 4 different manipulation tasks (pictured above). These tasks test different skill axis, ranging from task-level reasoning (e.g. detect target, move to object before goal, etc.) to fine-grained motor control (e.g. grab top of knob to turn). + +![](images/7a835bb50752f27737dfb01a7e97828ac3ccc28fbe9827a599d4760db54f73b3.jpg) +(c) Door Opening + +![](images/d7899741b36d8f2259b203af305fe17a144a3690eaae68b6b571561702b70fd2.jpg) +(d) Knob Turning + +![](images/bd1a213a787e7f17cde1cd7006fdff6eaa84d3258431ffd949eca61a437763ac.jpg) +Low-Cost Human Videos Transferred to Robot +Figure 4: In our problem setting we use a low-cost reacher grabber tool (left) to collect training demonstrations. These demonstrations are used to acquire a robot controller purely through distance/representation learning. The final system is deployed on a robot (right) to solve various tasks at test-time. + +100 demonstrations with diverse objects and randomized targets. Testing: During test time, the method was evaluated using 20 trails that involved unseen objects and new target printouts placed in randomly sampled positions. A trail is deemed successful if the robot pushes the object onto the target. This is the only task that did not require gripper control. + +Pick and Place This task (see Fig. 3b) is analogous to the pushing task (described above), except the robot must now pick the object up from its initial location and place it in a target bowl. This task requires more precision than pushing, since grasping an object is harder than localizing it. Training: We collect a dataset of 400 demonstrations for training, using randomized train objects and target bowls. Testing: The method is evaluated using 20 trails that used novel objects and unseen target bowls (i.e. analogous to pushing). A trail is successful if the robot places an object into the target. + +Door Opening The opening task (see Fig. 3c) requires the robot to approach a handle, grasp it, and then pull the door open. While conceptually simple, this task requires a great deal of precision, since the commanded actions must (almost) exactly match the direction of the door hinge. Training: We created a toy kitchen setting for this task, and collected 100 demonstrations of opening the door when starting from various initial positions. Testing: We evaluated on 20 real world test trials, where the robot's initial position and the door's initial state (e.g. position and hinge angle) were randomized. A trial was deemed successful if the door is opened fully. + +Knob Turning In this final task (see Fig. 3d) the robot must approach a knob in the toy kitchen, and then turn it clock-wise. Similar to the opening task, knob turning requires very precise motor control, since the robot must grab the knob at exactly the right location and carefully rotate in order to turn. Training: We collect a dataset of 100 knob turning demonstrations. Testing: The method is evaluated on 20 trials, with randomized robot/knob initial positions. Success is determined by if the knob is turned far enough to cause an audible "click." + +# 4.2. Robot-Free Data Collection + +A major strength of our setup is that training data $(\mathcal{D})$ can come from a different agent than the test time robot. We leverage this property to collect videos directly from humans operating a low-cost grabber stick (see Fig. 4, left), and use structure from motion [38] to recover actions. This allows us to collect demonstrations without an expensive tele-op setup [50, 23] or time-intensive kinesthetic demonstrations (i.e. manually moving the robot by hand). While based on prior work, our stick setup makes two important contributions: it is easier build and use than the highly instrumented setup in Song et. al. [42], and it provides higher + +![](images/8398b4afcf5be3c6f62a7c638a54e947fbf983308453f164d06f921b3c078d57.jpg) +Figure 5: Trajectories executed on the robot using our learned distance function. For each task, we show the $1^{st}$ person view (top) and $3^{rd}$ person view images (bottom). We show the learned visual embedding can encode functional distances between states for challenging tasks, like pushing, pick and place, door opening, and knob turning. + +quality images and action labels than the GoPro used in Young et. al. [48]. Please refer to Supplement A.2 for more information on our training and testing setups. We will release our dataset publicly. + +# 5. Experiments + +The following experiments seek to validate our distance learning framework on real control tasks (described above), and give some fundamental insights + +as to why they work. First, our baseline study (see Sec. 5.1) compares our method against representative SOTA techniques in the field. In addition, in Sec. 5.2 we analyze a specific scenario with highly multi-modal actions, where our model especially shines. Finally, the ablation study (see Sec. 5.3) investigates which components of our system are actually needed for good performance. + +
TaskOursBC [35, 48]IBC [13]IQL [20]
Pushing85%70%70%65%
Pick and Place60%30%30%45%
Door Opening55%40%45%50%
Knob Turning40%20%20%35%
+ +Table 1: We compare success rates for our method versus the baselines on all four manipulation tasks. Our distance learning method outperforms a suite of representative robot learning baselines. + +
# DemosPushingPick and Place
OursBCIBCOursBCIBC
5070%50%40%0%0%0%
10085%70%70%10%10%0%
20090%80%100%20%20%10%
400100%100%100%60%30%30%
600100%100%100%70%50%40%
+ +Table 2: We compare our distance learning method versus the behavior cloning baselines (BC [35, 48] and IBC [13]) when trained on varying amounts of data. Distance learning is able to learn faster than the baselines and scale better with data. + +# 5.1. Baseline Study + +We first note that our paper uses only demonstration data and no online data. Therefore, we compare our method against three SOTA baselines - ranging from standard behavior cloning, to energy based modeling, and Offline Reinforcement Learning (RL) - that cover a wide range of prior LfD work. The baseline methods are described briefly below. To make the comparisons fair, we parameterize all neural networks with the same R3M representation backbone used by our method, and tune hyper-parameters for best possible performance. Please check Supplement B.2 for in depth details. + +- Behavior Cloning [35, 48] (BC): BC learns a policy (via regression) that directly predicts actions from image observations: $\min_{\pi}||\pi(I_t,I_g) - a_t||_2$ . This provides a strong comparison point for a whole class of LfD methods that focus on learning motor policies directly. +- Implicit Behavior Cloning [13] (IBC): IBC learns an energy based model that can predict actions during test time via optimization: $a_{t} = \operatorname{argmin}_{a} E(a, I_{t}, I_{g})$ . This method is conceptually very similar to behavior cloning, but has the potential to better handle multi-modal action distributions and discontinuous actions. +- Implicit Q-Learning [20] (IQL): IQL is an + +offline-RL baseline that learns a Q function $Q(s,a) = Q((I_t,I_g),a_t)$ , alongside a policy that maximizes it $\pi (I_t,I_g) = \arg \max_aQ(s,a)$ . Note that IQL's training process requires us to annotate our offline trajectories $\mathcal{D}$ with a reward signal $r_t$ for each time-step. While this can be done automatically in our setting (Supplement B.2), this is an additional assumption that could be very burdensome in the general case. + +Our method is compared against the baselines on all four of our tasks (see Sec. 4.1). Results are reported in Table 1. Note how our distance learning approach achieves the highest success rates on all of four tasks. In addition, our method is much simpler than the strongest baseline (IQL), which requires an expert defined reward signal and uses a more complicated learning algorithm. The final test time performance is visualized in Fig. 5 and on our website: https://agilabs.github.io/manipulate-by-seeing/. + +Data Scaling A common cited strength of BC (versus RL) is its ability to continuously improve with additional expert data. Can our method do the same? Table 2 compares our distance learning method versus the BC/IBC baselines (on pushing/pick-place tasks), when trained on various amounts of data. Note how our method both learns faster than BC/IBC, and continuously scales with added demonstrations. This suggests that distance learning is a powerful alternative to BC on robotic manipulation tasks, no matter how much training data is available. + +# 5.2. Multi-Modality Experiment + +A common challenge in policy learning is effectively handling multi-modal action predictions. We propose a simple test scenario that allows us to test our method in this setting without any other confounding variables. Specifically, we create a "obstacle pushing" task where the robot must push an object to the target without disturbing an obstacle placed in the middle (see Fig. 6). Observe that there are two equally valid ways that the robot could push the block; to the left or to the right. We collect a training dataset of 100 demos, equally split between going left and right. This creates action multi-modality where the agent must arbitrarily choose between two scenarios in order to successfully perform the task, but will fail if it simply averages the actions and pushes the block forward (into the obstacle). We expect that standard BC will fall into this failure mode, since it is trained using standard L2 action regression. In contrast, our method should still work since the low distance states will move the robot either to the left or right state, thus allowing it to make a discrete choice. + +![](images/eee2abf71c645549d93ea0e946d29a3a02e616b71efbba8900beafd4e890dd0d.jpg) +Figure 6: Our method can solve tasks with highly multi-modal action distributions that are difficult for the baselines. In this example, our distance learning controller successfully pushes the block around the obstacle, while Behavior Cloning learns to incorrectly push the block forward (i.e. predicts mean action). + +To verify this hypothesis, we test our method, the BC baseline, and IQL (the strongest non-BC baseline) on 20 trials in this task setting. Success is judged similarly as to pushing (see Sec. 4.1), with the added condition that the robot should not push the obstacles into the target. Our method achieves a $95\%$ success rate, versus $0\%$ for BC and $90\%$ for IQL in this setting! As expected, our method is able to greatly improve upon BC in this setting, because it explicitly avoids action prediction. While IQL should not suffer as badly from multi-modality, thanks to its learned value function, our method is still able to outperform it despite being simpler algorithmically and trained without reward signal. + +# 5.3. Ablation Study + +Our final experiment removes components of our method in order to determine which parts were most crucial for control performance. The representation ablation replaces the R3M backbone in our neural network with a pre-trained ImageNet representation (using same ResNet-18 architecture for both). We expect the ImageNet weights to be weaker, since they were trained on a smaller dataset that did not include egocentric videos (ImageNet vs Ego4D used by R3M). Additionally, the dynamics ablation removes the dynamics module during training, thus leaving the distance model/embeddings without any physical grounding. This is similar to the method from Hahn et. al. [15] (see + +
OursImageNet Repr.No Dynamics [15]
Pushing90%40%60%
Pick and Place60%40%35%
Door Opening55%45%50%
Knob Turning40%15%40%
+ +Table 3: This table compares success rates for our method versus the ablations on the all four tasks. As you can see, removing the dynamics module from our method during training and training with a weaker representation both result in worse performance. + +Sec. 2), with an added dynamics module. We expect this ablation to perform worse on manipulation tasks, because dynamics is more important in this setting v.s. visual navigation. + +The two ablations are evaluated and compared against our method on all four test tasks (see Table 3). We find that our method strongly outperforms both of our baselines, which suggests that our intuition outline above is correct. In particular, we conclude that stronger representations can directly stronger control performance using our method. Additionally, this shows that the dynamics grounding is important to ensure that our learned distances transfer onto real robot hardware during test time, especially in manipulation tasks that involve object interactions/contact. + +# 6. Discussion + +This paper demonstrates that neural image representations can be more than just state representations: a simple metric defined within the embedding space can help infer robot actions. We leverage this insight to learn a distance function and dynamics function using minimal low-cost human data. These modules parameterize a robotic planner that is validated across 4 representative manipulation tasks. Despite its simplicity, our method is able to outperform standard imitation learning and offline-RL methods in the robot learning field. This is especially true in situations involving multi-modal action distributions, where our method entirely outclasses a standard BC baseline. Finally, the ablation study demonstrates that stronger representations directly result in stronger control performance, and that dynamics grounding is important for our scheme to work in practice. + +Future Work We hope that this paper inspires future work in the space of representation learning and robotics. Follow up works should improve visual representations specifically for robotics, by more precisely capturing fine-grained interactions between gripper/- + +hand and objects. This could improve performance on tasks like knob turning, where the pre-trained R3M encoder often struggled to detect small shifts of the gripper relative to the knob. We also hope that our contrastive learning method could be extended to learn entirely without action labels. This would allow us to train on large scale manipulation datasets (e.g. YouTube videos) and transfer the results directly to the control setting. Finally, it would be ideal if data collected using our low-cost stick (see Fig. 4) could be used with a stronger, more reliable (commercial) gripper, despite the domain gap. This would enable us to solve more tasks during test time. + +# References + +[1] Pieter Abbeel and Andrew Y Ng. Apprenticeship learning via inverse reinforcement learning. In Proceedings of the twenty-first international conference on Machine learning, page 1, 2004. +[2] OpenAI: Marcin Andrychowicz, Bowen Baker, Maciek Chociej, Rafal Jozefowicz, Bob McGrew, Jakub Pachocki, Arthur Petron, Matthias Plappert, Glenn Powell, Alex Ray, et al. Learning dexterous in-hand manipulation. The International Journal of Robotics Research, 39(1):3-20, 2020. +[3] Daniel Angelov, Yordan Hristov, Michael Burke, and Subramanian Ramamoorthy. Composing diverse policies for temporally extended tasks. IEEE Robotics and Automation Letters, 5(2):2658-2665, 2020. +[4] Brenna D Argall, Sonia Chernova, Manuela Veloso, and Brett Browning. A survey of robot learning from demonstration. Robotics and autonomous systems, 57(5):469-483, 2009. +[5] Yusuf Aytar, Tobias Pfaff, David Budden, Thomas Paine, Ziyu Wang, and Nando De Freitas. Playing hard exploration games by watching youtube. Advances in neural information processing systems, 31, 2018. +[6] Shikhar Bahl, Abhinav Gupta, and Deepak Pathak. Human-to-robot imitation in the wild. RSS, 2022. +[7] Aude Billard, Sylvain Calinon, Ruediger Dillmann, and Stefan Schaal. Survey: Robot programming by demonstration. Handbook of robotics, 59(BOOK_CHAP), 2008. +[8] Annie S Chen, Suraj Nair, and Chelsea Finn. Learning generalizable robotic reward functions from" in-the-wild" human videos. arXiv preprint arXiv:2103.16817, 2021. +[9] Lili Chen, Kevin Lu, Aravind Rajeswaran, Kimin Lee, Aditya Grover, Misha Laskin, Pieter Abbeel, Aravind Srinivas, and Igor Mordatch. Decision transformer: Reinforcement learning via sequence modeling. Advances in neural information processing systems, 34:15084-15097, 2021. +[10] Sudeep Dasari and Abhinav Gupta. Transformers for one-shot imitation learning. In CoRL 2020, 2020. + +[11] Sudeep Dasari, Abhinav Gupta, and Vikash Kumar. Learning dexterous manipulation from exemplar object trajectories and pre-grasps. In IEEE International Conference on Robotics and Automation 2023, 2023. +[12] Sudeep Dasari, Jianren Wang, Joyce Hong, Shikhar Bahl, Yixin Lin, Austin Wang, Abitha Thankaraj, Karanbir Chahal, Berk Calli, Saurabh Gupta, et al. Rb2: Robotic manipulation benchmarking with a twist. arXiv preprint arXiv:2203.08098, 2022. +[13] Pete Florence, Corey Lynch, Andy Zeng, Oscar Ramirez, Ayzaan Wahid, Laura Downs, Adrian Wong, Johnny Lee, Igor Mordatch, and Jonathan Tompson. Implicit behavioral cloning. Conference on Robot Learning (CoRL), 2021. +[14] Kristen Grauman, Andrew Westbury, Eugene Byrne, Zachary Chavis, Antonino Furnari, Rohit Girdhar, Jackson Hamburger, Hao Jiang, Miao Liu, Xingyu Liu, et al. Ego4d: Around the world in 3,000 hours of egocentric video. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18995-19012, 2022. +[15] Meera Hahn, Devendra Singh Chaplot, Shubham Tulsiani, Mustafa Mukadam, James M Rehg, and Abhinav Gupta. No rl, no simulation: Learning to navigate without navigating. Advances in Neural Information Processing Systems, 34:26661-26673, 2021. +[16] Ankur Handa, Arthur Allshire, Viktor Makoviychuk, Aleksei Petrenko, Ritvik Singh, Jingzhou Liu, Denys Makoviichuk, Karl Van Wyk, Alexander Zhurkevich, Balakumar Sundaralingam, Yashraj Narang, Jean-Francois Lafleche, Dieter Fox, and Gavriel State. Dextreme: Transfer of agile in-hand manipulation from simulation to reality. arXiv, 2022. +[17] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. +[18] Eric Jang, Alex Irpan, Mohi Khansari, Daniel Kappler, Frederik Ebert, Corey Lynch, Sergey Levine, and Chelsea Finn. Bc-z: Zero-shot task generalization with robotic imitation learning. In Conference on Robot Learning, pages 991-1002. PMLR, 2022. +[19] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. +[20] Ilya Kostrikov, Ashvin Nair, and Sergey Levine. Offline reinforcement learning with implicit q-learning. arXiv preprint arXiv:2110.06169, 2021. +[21] Aviral Kumar, Rishabh Agarwal, Dibya Ghosh, and Sergey Levine. Implicit under-parameterization inhibits data-efficient deep reinforcement learning. arXiv preprint arXiv:2010.14498, 2020. +[22] Ashish Kumar, Zipeng Fu, Deepak Pathak, and Jitendra Malik. Rma: Rapid motor adaptation for legged robots. arXiv preprint arXiv:2107.04034, 2021. +[23] Vikash Kumar and Emanuel Todorov. Mujoco haptix: A virtual reality system for hand manipulation. In + +Humanoid Robots (Humanoids), 2015 IEEE-RAS 15th International Conference on, pages 657-663. IEEE, 2015. +[24] Joonho Lee, Jemin Hwangbo, Lorenz Wellhausen, Vladlen Koltun, and Marco Hutter. Learning quadrupedal locomotion over challenging terrain. Science robotics, 5(47):eabc5986, 2020. +[25] Sergey Levine, Aviral Kumar, George Tucker, and Justin Fu. Offline reinforcement learning: Tutorial, review, and perspectives on open problems. arXiv preprint arXiv:2005.01643, 2020. +[26] Yixin Lin and Austin Wang. Polymetis: a real-time pytorch controller manager. In https://github.com/facebookresearch/polymetis, 2021. +[27] Corey Lynch, Mohi Khansari, Ted Xiao, Vikash Kumar, Jonathan Tompson, Sergey Levine, and Pierre Sermanet. Learning latent plans from play. In Conference on robot learning, pages 1113-1132. PMLR, 2020. +[28] Andriy Mnih and Koray Kavukcuoglu. Learning word embeddings efficiently with noise-contrastive estimation. Advances in neural information processing systems, 26, 2013. +[29] Suraj Nair, Aravind Rajeswaran, Vikash Kumar, Chelsea Finn, and Abhinav Gupta. R3m: A universal visual representation for robot manipulation. CoRL, 2022. +[30] Aaron van den Oord, Yazhe Li, and Oriol Vinyals. Representation learning with contrastive predictive coding. arXiv preprint arXiv:1807.03748, 2018. +[31] Simone Parisi, Aravind Rajeswaran, Senthil Purushwalkam, and Abhinav Gupta. The unsurprising effectiveness of pre-trained vision models for control. arXiv preprint arXiv:2203.03580, 2022. +[32] Ilija Radosavovic, Tete Xiao, Stephen James, Pieter Abbeel, Jitendra Malik, and Trevor Darrell. Realworld robot learning with masked visual pre-training. CoRL, 2022. +[33] Aravind Rajeswaran, Vikash Kumar, Abhishek Gupta, Giulia Vezzani, John Schulman, Emanuel Todorov, and Sergey Levine. Learning complex dexterous manipulation with deep reinforcement learning and demonstrations. arXiv preprint arXiv:1709.10087, 2017. +[34] Frank Rosenblatt. Principles of neurodynamics. perceptrons and the theory of brain mechanisms. Technical report, Cornell Aeronautical Lab Inc Buffalo NY, 1961. +[35] Stéphane Ross, Geoffrey Gordon, and Drew Bagnell. A reduction of imitation learning and structured prediction to no-regret online learning. In Proceedings of the fourteenth international conference on artificial intelligence and statistics, pages 627-635, 2011. +[36] Stefan Schaal. Is imitation learning the route to humanoid robots? Trends in cognitive sciences, 3(6):233-242, 1999. +[37] Karl Schmeckpeper, Oleh Rybkin, Kostas Daniilidis, Sergey Levine, and Chelsea Finn. Reinforcement learning with videos: Combining offline observations with + +interaction. In Conference on Robot Learning, pages 339-354. PMLR, 2021. +[38] Johannes Lutz Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In Conference on Computer Vision and Pattern Recognition (CVPR), 2016. +[39] Pierre Sermanet, Corey Lynch, Yevgen Chebotar, Jasmine Hsu, Eric Jang, Stefan Schaal, Sergey Levine, and Google Brain. Time-contrastive networks: Self-supervised learning from video. In 2018 IEEE international conference on robotics and automation (ICRA), pages 1134–1141. IEEE, 2018. +[40] Pierre Sermanet, Kelvin Xu, and Sergey Levine. Unsupervised perceptual rewards for imitation learning. arXiv preprint arXiv:1612.06699, 2016. +[41] Nur Muhammad Mahi Shafiullah, Zichen Jeff Cui, Ariuntuya Altanzaya, and Lerrel Pinto. Behavior transformers: Cloning $k$ modes with one stone. In Thirty-Sixth Conference on Neural Information Processing Systems, 2022. +[42] Shuran Song, Andy Zeng, Johnny Lee, and Thomas Funkhouser. Grasping in the wild: Learning 6 dof closed-loop grasping from low-cost demonstrations. Robotics and Automation Letters, 2020. +[43] Richard S Sutton and Andrew G Barto. Reinforcement learning: An introduction. MIT press, 2018. +[44] Michita Imai Takuma Seno. d3rlpy: An offline deep reinforcement library. In NeurIPS 2021 Offline Reinforcement Learning Workshop, December 2021. +[45] Emanuel Todorov, Tom Erez, and Yuval Tassa. Mu-joco: A physics engine for model-based control. In 2012 IEEE/RSJ international conference on intelligent robots and systems, pages 5026-5033. IEEE, 2012. +[46] Faraz Torabi, Garrett Warnell, and Peter Stone. Generative adversarial imitation from observation. arXiv preprint arXiv:1807.06158, 2018. +[47] Annie Xie, Avi Singh, Sergey Levine, and Chelsea Finn. Few-shot goal inference for visuomotor learning and planning. In Conference on Robot Learning, pages 40-52. PMLR, 2018. +[48] Sarah Young, Dhiraj Gandhi, Shubham Tulsiani, Abhinav Gupta, Pieter Abbeel, and Lerrel Pinto. Visual imitation made easy. In Conference on Robot Learning, pages 1992-2005. PMLR, 2021. +[49] Tianhe Yu, Deirdre Quillen, Zhanpeng He, Ryan Julian, Karol Hausman, Chelsea Finn, and Sergey Levine. Meta-world: A benchmark and evaluation for multi-task and meta reinforcement learning. In _Conference on Robot Learning (CoRL)_, 2019. +[50] Tianhao Zhang, Zoe McCarthy, Owen Jow, Dennis Lee, Xi Chen, Ken Goldberg, and Pieter Abbeel. Deep imitation learning for complex manipulation tasks from virtual reality teleoperation. In 2018 IEEE International Conference on Robotics and Automation (ICRA), pages 5628-5635. IEEE, 2018. \ No newline at end of file diff --git a/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/images.zip b/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..afcf2f2b7baa36453dd49f9643e6249780483c26 --- /dev/null +++ b/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:f727ad0f50611478aa8582fe499b1ede90c951f88b3b29b798eaffdaf8f63da3 +size 514408 diff --git a/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/layout.json b/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..8e345bf5b11891911b45d5075add7e3599151484 --- /dev/null +++ b/2023/Manipulate by Seeing_ Creating Manipulation Controllers from Pre-Trained Representations/layout.json @@ -0,0 +1,7531 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 91, + 103, + 503, + 138 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 103, + 503, + 138 + ], + "spans": [ + { + "bbox": [ + 91, + 103, + 503, + 138 + ], + "type": "text", + "content": "Manipulate by Seeing: Creating Manipulation Controllers from Pre-Trained Representations" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 39, + 161, + 563, + 177 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 39, + 161, + 563, + 177 + ], + "spans": [ + { + "bbox": [ + 39, + 161, + 563, + 177 + ], + "type": "text", + "content": "Jianren Wang* Sudeep Dasari* Mohan Kumar Srirama Shubham Tulsiani Abhinav Gupta" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 236, + 189, + 380, + 204 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 236, + 189, + 380, + 204 + ], + "spans": [ + { + "bbox": [ + 236, + 189, + 380, + 204 + ], + "type": "text", + "content": "Carnegie Mellon University" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 140, + 231, + 194, + 243 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 140, + 231, + 194, + 243 + ], + "spans": [ + { + "bbox": [ + 140, + 231, + 194, + 243 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 255, + 290, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 255, + 290, + 568 + ], + "spans": [ + { + "bbox": [ + 47, + 255, + 290, + 568 + ], + "type": "text", + "content": "The field of visual representation learning has seen explosive growth in the past years, but its benefits in robotics have been surprisingly limited so far. Prior work uses generic visual representations as a basis to learn (task-specific) robot action policies (e.g., via behavior cloning). While the visual representations do accelerate learning, they are primarily used to encode visual observations. Thus, action information has to be derived purely from robot data, which is expensive to collect! In this work, we present a scalable alternative where the visual representations can help directly infer robot actions. We observe that vision encoders express relationships between image observations as distances (e.g., via embedding dot product) that could be used to efficiently plan robot behavior. We operationalize this insight and develop a simple algorithm for acquiring a distance function and dynamics predictor, by finetuning a pre-trained representation on human collected video sequences. The final method is able to substantially outperform traditional robot learning baselines (e.g., " + }, + { + "bbox": [ + 47, + 255, + 290, + 568 + ], + "type": "inline_equation", + "content": "70\\%" + }, + { + "bbox": [ + 47, + 255, + 290, + 568 + ], + "type": "text", + "content": " success v.s. " + }, + { + "bbox": [ + 47, + 255, + 290, + 568 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 47, + 255, + 290, + 568 + ], + "type": "text", + "content": " for behavior cloning on pick-place) on a suite of diverse real-world manipulation tasks. It can also generalize to novel objects, without using any robot demonstrations during train time. For visualizations of the learned policies please check: https://agi-labs.github.io/manipulate-by-seeing/." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 590, + 139, + 604 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 590, + 139, + 604 + ], + "spans": [ + { + "bbox": [ + 47, + 590, + 139, + 604 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 610, + 287, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 610, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 610, + 287, + 696 + ], + "type": "text", + "content": "The lack of suitable, large-scale data-sets is a major bottleneck in robot learning. Due to the physical nature of data collection, robotics data-sets are: (a) hard to scale; (b) collected in sterile, non-realistic environments (e.g. robotics lab); (c) too homogeneous (e.g. toy objects with fixed backgrounds/lighting). In contrast, vision data-sets contain diverse tasks, objects," + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 307, + 230, + 545, + 376 + ], + "blocks": [ + { + "bbox": [ + 307, + 230, + 545, + 376 + ], + "lines": [ + { + "bbox": [ + 307, + 230, + 545, + 376 + ], + "spans": [ + { + "bbox": [ + 307, + 230, + 545, + 376 + ], + "type": "image", + "image_path": "6539cafe82d4a0cd000cfd89ebcd050b34681416a30c0dabc063f42b2c8cb00b.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 384, + 547, + 492 + ], + "lines": [ + { + "bbox": [ + 304, + 384, + 547, + 492 + ], + "spans": [ + { + "bbox": [ + 304, + 384, + 547, + 492 + ], + "type": "text", + "content": "Figure 1: This paper proposes to solve a range of manipulation tasks (e.g. pushing) by learning a functional distance metric within the embedding space of a pretrained network. This distance function - in combination with a learned dynamics model - can be used to greedily plan for robot actions that reach a goal state. Our experiments reveal that the proposed method can outperform SOTA robot learning methods across four diverse manipulation tasks." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 518, + 546, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 518, + 546, + 568 + ], + "spans": [ + { + "bbox": [ + 304, + 518, + 546, + 568 + ], + "type": "text", + "content": "and settings (e.g. Ego4D [14]). Therefore, recent approaches have explored transferring priors from large scale vision data-sets to robotics settings. What is the right way to accomplish this?" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 570, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 547, + 714 + ], + "type": "text", + "content": "Prior work uses vision data-sets to pre-train representations [31, 29, 32] that encode image observations as state vectors (i.e. " + }, + { + "bbox": [ + 304, + 570, + 547, + 714 + ], + "type": "inline_equation", + "content": "s = R(i)" + }, + { + "bbox": [ + 304, + 570, + 547, + 714 + ], + "type": "text", + "content": "). This visual representation is then simply used as an input for a controller learned from robot data - e.g. a policy " + }, + { + "bbox": [ + 304, + 570, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\pi(a|s)" + }, + { + "bbox": [ + 304, + 570, + 547, + 714 + ], + "type": "text", + "content": ", trained with expert data via Behavior Cloning [35], or a Value function " + }, + { + "bbox": [ + 304, + 570, + 547, + 714 + ], + "type": "inline_equation", + "content": "V(s)" + }, + { + "bbox": [ + 304, + 570, + 547, + 714 + ], + "type": "text", + "content": ", trained using exploratory roll-outs via Reinforcement Learning [43]. Is this approach the most efficient way to use pre-trained representations? We argue that pre-trained networks can do more than just represent states, since their latent space already encodes semantic, task-level information - e.g. by plac" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 702, + 167, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 167, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 167, + 712 + ], + "type": "text", + "content": "*Denotes equal contribution." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "spans": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "type": "text", + "content": "3859" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 119 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 119 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 119 + ], + "type": "text", + "content": "ing semantically similar states more closely together. Leveraging this structure to infer actions, could enable us to use significantly less robotic data during train time." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "spans": [ + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "text", + "content": "Our paper achieves this by fine-tuning a pre-trained representation into: (a) a one-step dynamics module, " + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "inline_equation", + "content": "F(s,a)" + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "text", + "content": ", that predicts how the robot's next state given the current state/action; and (b) a \"functional distance module\", " + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "inline_equation", + "content": "d(s,g)" + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "text", + "content": ", that calculates how close the robot is to achieving its goal " + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "inline_equation", + "content": "g" + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "text", + "content": " in the state " + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "text", + "content": ". The distance function is learned with limited human demonstration data, using a contrastive learning objective (see Fig. 2). Both " + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 46, + 121, + 288, + 335 + ], + "type": "text", + "content": " are used in conjunction to greedily plan robot actions (see Fig. 1 for intuition). Our experiments demonstrate that this approach works better than policy learning (via Behavior Cloning), because the pre-trained representation itself does the heavy lifting (thanks to its structure) and we entirely dodge the challenge of multi-modal, sequential action prediction. Furthermore, our learned distance function is both stable and easy to train, which allows it to easily scale and generalize to new scenarios." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 337, + 287, + 373 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 337, + 287, + 373 + ], + "spans": [ + { + "bbox": [ + 47, + 337, + 287, + 373 + ], + "type": "text", + "content": "To summarize, we show a simple approach for exploiting the information hidden in pre-trained visual representations. Our contributions include:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 57, + 383, + 287, + 560 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 57, + 383, + 287, + 431 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 383, + 287, + 431 + ], + "spans": [ + { + "bbox": [ + 57, + 383, + 287, + 431 + ], + "type": "text", + "content": "- Developing a simple algorithm for acquiring a distance function and dynamics model by fine-tuning a pre-trained visual representation on minimal (human collected) data." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 57, + 441, + 287, + 502 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 441, + 287, + 502 + ], + "spans": [ + { + "bbox": [ + 57, + 441, + 287, + 502 + ], + "type": "text", + "content": "- Creating an effective manipulation controller that substantially outperforms State-of-the-Art (SOTA) prior methods from the robot learning community (e.g. Behavior Cloning [35], Offline-RL [20], etc.)." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 57, + 512, + 287, + 560 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 512, + 287, + 560 + ], + "spans": [ + { + "bbox": [ + 57, + 512, + 287, + 560 + ], + "type": "text", + "content": "- Demonstrating that our approach can handle four realistic manipulation tasks, generalize to new objects and settings, and solve challenging scenarios w/ multi-modal action distributions." + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 47, + 573, + 148, + 586 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 573, + 148, + 586 + ], + "spans": [ + { + "bbox": [ + 47, + 573, + 148, + 586 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "type": "text", + "content": "Behavior Cloning This paper adopts the Learning from Demonstration (LfD) problem setting [4, 7, 36], where a robot must acquire manipulation behaviors given expert demonstration trajectories. A standard approach in this space is to learn a policy " + }, + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "type": "inline_equation", + "content": "(\\pi)" + }, + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "type": "text", + "content": " via Behavior Cloning [35] (BC), which directly optimizes " + }, + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\pi" + }, + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "type": "text", + "content": " to match the expert's action distribution. While conceptually simple, realistic action distributions are difficult to model, since they are inherently multi-modal and even small errors compound over time. Thus, policy" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 72, + 547, + 180 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 180 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 180 + ], + "type": "text", + "content": "learning requires extensive intensive network engineering (e.g. transformer architectures [10, 9], multi-modal prediction heads [41, 27], etc.) and/or human-in-the-loop data collection algorithms [35, 18] to work in practice. Instead of learning a policy, we learn a functional distance metric that captures the how “close” a state is to reaching a target goal. This lets us build a manipulation controller using a simple greedy planner during test time, without any explicit action prediction!" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 198, + 547, + 426 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 198, + 547, + 426 + ], + "spans": [ + { + "bbox": [ + 304, + 198, + 547, + 426 + ], + "type": "text", + "content": "Offline RL Broadly speaking, the field of Reinforcement Learning [43] (RL) seeks to learn a value/advantage/Q function by assuming access to a reward signal, which \"evaluates\" a state (e.g. " + }, + { + "bbox": [ + 304, + 198, + 547, + 426 + ], + "type": "inline_equation", + "content": "+1" + }, + { + "bbox": [ + 304, + 198, + 547, + 426 + ], + "type": "text", + "content": " reward for reaching goal). RL algorithms usually require environment interaction to learn, though the field of Offline-RL [25] seeks to extend these systems to learn from offline trajectories. While these approaches have created some impressive robotics demos ranging from locomotion [24, 22] to dexterous manipulation [2, 16, 11], RL methods are data hungry [33, 2], difficult to implement, require extreme \"reward engineering\" (e.g. MetaWorld [49] reward functions are 50 lines!), hampered by unstable learning dynamics [21], and poorly generalize in realistic robotic manipulation settings [12]. In contrast, our method learns a proxy for value functions (i.e. distances) purely from offline data, using representation learning algorithms (from the vision field) that are much more stable." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 444, + 547, + 648 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 444, + 547, + 648 + ], + "spans": [ + { + "bbox": [ + 304, + 444, + 547, + 648 + ], + "type": "text", + "content": "Learning Visual Rewards Our distance learning approach is analogous to learning visual rewards. Prior work learned success classifiers [40, 47, 46] and/or video similarity metrics [39, 5, 37, 6, 8] from expert video demonstrations. Once learned, these modules were used to parameterize reward functions that could be used to train policies [1], and/or as cost functions for planners [3]. However, these papers mostly consider simple settings (e.g. simulation) or require the test setting to exactly match train time. This is because the learned reward functions are often noisy and/or poorly generalize to new scenes. In contrast, our learned distance metric is stable and can easily adapt to new scenarios, thanks to the pre-trained network's latent structure. This allows us to solve diverse tasks during test time on a real robot, using a simple (and fast) shooting method planner." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 665, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 547, + 715 + ], + "type": "text", + "content": "Distance Learning for Navigation Finally, prior work from Hahn et. al. [15] explored distance learning to solve visual navigation tasks from offline video data. Our work is inspired from this approach, but makes" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 732, + 316, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 732, + 316, + 742 + ], + "spans": [ + { + "bbox": [ + 295, + 732, + 316, + 742 + ], + "type": "text", + "content": "3860" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 169 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 169 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 169 + ], + "type": "text", + "content": "three key innovations in order to apply it to (more challenging) robotic manipulation tasks. First, we simplify the network architecture to operate in representation space instead of using a graph network. Second, we learn the distances using a self-supervised contrastive loss, instead of relying on hand-defined objectives. And third, we add a dynamics function that proves to be critical for effective manipulation (see Table. 3)." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 180, + 117, + 193 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 180, + 117, + 193 + ], + "spans": [ + { + "bbox": [ + 47, + 180, + 117, + 193 + ], + "type": "text", + "content": "3. Methods" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "spans": [ + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "text", + "content": "Preliminaries This paper considers learning goal-conditioned manipulation behaviors from image observations. The robot agent is provided a goal observation " + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "inline_equation", + "content": "(I_g) - \\mathrm{e.g.}" + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "text", + "content": " target object in robot gripper - and an observation " + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "inline_equation", + "content": "(I_t)" + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "text", + "content": " for the current time-step " + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "text", + "content": ". The robot must process these observations and decide an action to take " + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "inline_equation", + "content": "(a_{t})" + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "text", + "content": ". Note that all observations " + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "inline_equation", + "content": "(I)" + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "text", + "content": " are wrist-mounted RGB camera images with no depth or proprioceptive data. Additionally, the actions " + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "inline_equation", + "content": "(a)" + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "text", + "content": " are specified as arbitrary " + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "inline_equation", + "content": "SE(3)" + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "text", + "content": " transforms for the robot's end-effector (more in Supplement B.1). Our goal is to learn a robotic manipulation controller, using a set of training trajectories " + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "inline_equation", + "content": "\\mathcal{D} = \\{\\tau_1,\\dots ,\\tau_N\\}" + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "inline_equation", + "content": "\\tau_{i} = \\{I_{g},I_{1},a_{1},\\ldots ,a_{T - 1},I_{T}\\}" + }, + { + "bbox": [ + 46, + 201, + 289, + 381 + ], + "type": "text", + "content": ". The test and train settings are visualized in Fig. 4." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "spans": [ + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "type": "text", + "content": "Our Approach Our method leverages a pre-trained representation network, " + }, + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "type": "inline_equation", + "content": "R" + }, + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "type": "text", + "content": ", to encode observations, " + }, + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "type": "inline_equation", + "content": "i_{t} = R(I_{t})" + }, + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "type": "text", + "content": ", and enable control via distance learning. Specifically, we use contrastive representation learning methods [30, 28] to learn a distance metric, " + }, + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "type": "inline_equation", + "content": "d(i_j,i_k)" + }, + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "type": "text", + "content": " within the pre-trained embedding space. The key idea is to use this distance metric to select which of the possible future state is closest to the goal state. But how do we predict possible future states? We explicitly learn a dynamics function, " + }, + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "type": "inline_equation", + "content": "F(i_{t},a_{t})" + }, + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "type": "text", + "content": " that predicts future state for a possible action " + }, + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "type": "inline_equation", + "content": "a_{t}" + }, + { + "bbox": [ + 46, + 398, + 289, + 627 + ], + "type": "text", + "content": ". During test time, we predict multiple future states using different possible action and select the one which is closest to goal state. The following sections describe the learned dynamics module (see Sec. 3.1), distance learning method (see Sec. 3.2), and test-time controller for robot deployment (see Sec. 3.4) in detail. Fig. 2 provides a visual depiction of our training algorithm. Pseudo-code and hyper-parameters are presented in Supplement A.3." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 635, + 168, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 635, + 168, + 647 + ], + "spans": [ + { + "bbox": [ + 47, + 635, + 168, + 647 + ], + "type": "text", + "content": "3.1. Dynamics Prediction" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "content": "An ideal dynamics function would perfectly capture how a robot's actions effects its environment. In our setting, this translates to predicting the next observation embedding, given the current embedding and commanded action: " + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "inline_equation", + "content": "F(i_{t},a_{t}) = i_{t + 1}" + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "content": ". Thus, " + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 46, + 653, + 288, + 715 + ], + "type": "text", + "content": " can" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 72, + 547, + 180 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 180 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 180 + ], + "type": "text", + "content": "be learned via regression by minimizing reconstruction loss in embedding space: " + }, + { + "bbox": [ + 304, + 72, + 547, + 180 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_F = ||F(i_t,a_t) - i_{t + 1}||_2" + }, + { + "bbox": [ + 304, + 72, + 547, + 180 + ], + "type": "text", + "content": " (see Fig. 2, left). This module has two primary uses: (1) during training it acts as a physically grounded regularizer that relays action information into the embedding space, and (2) during test time it enables the robot to plan actions in embedding space. As you will see, both properties are leveraged extensively in the rest of our method." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 188, + 484, + 201 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 188, + 484, + 201 + ], + "spans": [ + { + "bbox": [ + 306, + 188, + 484, + 201 + ], + "type": "text", + "content": "3.2. Learning Task-Centric Distances" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "spans": [ + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "text", + "content": "Our distance module " + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "inline_equation", + "content": "d(i_j, i_k)" + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "text", + "content": " seeks to learn functional distances that encode task-centric reasoning (e.g. must reach for object before pushing it) alongside important physical priors (e.g. object is to the left so move left). How can we learn such a distance space? Since we have access to expert trajectories " + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "text", + "content": ", we know that the next state sequentially visited by the expert " + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "inline_equation", + "content": "(i_{t+1})" + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "text", + "content": " is closer to the goal state " + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "inline_equation", + "content": "(i_g)" + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "text", + "content": " than arbitrary states " + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "inline_equation", + "content": "(\\hat{i})" + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "text", + "content": " reachable from " + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "inline_equation", + "content": "i_t" + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "text", + "content": " - i.e. " + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "inline_equation", + "content": "d(i_{t+1}, i_g) << d(\\hat{i}, i_g)" + }, + { + "bbox": [ + 304, + 206, + 545, + 316 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "spans": [ + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "type": "text", + "content": "Our insight is that a distance metric with these properties can be learned via contrastive learning. Specifically, we define " + }, + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "type": "inline_equation", + "content": "d(i_j,i_k) = -\\cos (i_j,i_k)" + }, + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "type": "inline_equation", + "content": "\\cos" + }, + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "type": "text", + "content": " is cosine similarity, and sample a observation-state-goal tuples " + }, + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "type": "inline_equation", + "content": "(i_t,a_t,i_g)" + }, + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "type": "text", + "content": ", alongside random noise action candidates " + }, + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "type": "inline_equation", + "content": "\\hat{a}^1,\\dots ,\\hat{a}^n" + }, + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "type": "text", + "content": " sampled from " + }, + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 304, + 317, + 545, + 399 + ], + "type": "text", + "content": ". We apply NCE loss and get:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 307, + 409, + 545, + 436 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 409, + 545, + 436 + ], + "spans": [ + { + "bbox": [ + 307, + 409, + 545, + 436 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {d} = \\frac {e x p (- d (F (i _ {t} , a _ {t}) , i _ {g}))}{e x p (- d (F (i _ {t} , a _ {t}) , i _ {g})) + \\Sigma_ {j} e x p (- d (F (i _ {t} , \\hat {a} ^ {j}) , i _ {g}))}", + "image_path": "85a20b981ad841cfb5fa4558adf9bdcc3f40d7803dcc37ca9b056d8e0e931567.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "spans": [ + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "type": "text", + "content": "This loss creates a warped embedding space where " + }, + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "type": "inline_equation", + "content": "i_{t+1}" + }, + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "type": "text", + "content": " (hallucinated by " + }, + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "type": "inline_equation", + "content": "F(i_t, a_t)" + }, + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "type": "text", + "content": ") is pushed closer towards the goal state " + }, + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "type": "inline_equation", + "content": "i_g" + }, + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "type": "text", + "content": ", than other arbitrary states reachable from " + }, + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "type": "inline_equation", + "content": "i_t" + }, + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "type": "text", + "content": " (again hallucinated by " + }, + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 304, + 443, + 545, + 515 + ], + "type": "text", + "content": "). This process is shown visually in Fig. 2 (right), and precisely satisfies our criteria for good distance functions." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 524, + 405, + 537 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 524, + 405, + 537 + ], + "spans": [ + { + "bbox": [ + 306, + 524, + 405, + 537 + ], + "type": "text", + "content": "3.3. Training Details" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 542, + 545, + 662 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 542, + 545, + 662 + ], + "spans": [ + { + "bbox": [ + 304, + 542, + 545, + 662 + ], + "type": "text", + "content": "Both modules are trained jointly resulting in a final loss: " + }, + { + "bbox": [ + 304, + 542, + 545, + 662 + ], + "type": "inline_equation", + "content": "\\mathcal{L} = \\lambda_d\\mathcal{L}_d + \\lambda_F\\mathcal{L}_F" + }, + { + "bbox": [ + 304, + 542, + 545, + 662 + ], + "type": "text", + "content": ". Note that " + }, + { + "bbox": [ + 304, + 542, + 545, + 662 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 304, + 542, + 545, + 662 + ], + "type": "text", + "content": " is implemented as small neural networks with 2 hidden layers, while " + }, + { + "bbox": [ + 304, + 542, + 545, + 662 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 304, + 542, + 545, + 662 + ], + "type": "text", + "content": " does not require any extra learned networks since its implemented via contrastive loss in the metric space. The shared representation network, " + }, + { + "bbox": [ + 304, + 542, + 545, + 662 + ], + "type": "inline_equation", + "content": "R" + }, + { + "bbox": [ + 304, + 542, + 545, + 662 + ], + "type": "text", + "content": ", we use is ResNet-18 initialized by R3M weights. The ADAM [19] stochastic gradient descent optimizer and back-propagation are used to train the network end-to-end. Please refer to Supplement A.3. for additional details." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 670, + 466, + 684 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 670, + 466, + 684 + ], + "spans": [ + { + "bbox": [ + 306, + 670, + 466, + 684 + ], + "type": "text", + "content": "3.4. Test Time Robot Deployment" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "content": "During test time our learned modules must be able to solve real manipulation tasks when deployed on" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 732, + 314, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 732, + 314, + 742 + ], + "spans": [ + { + "bbox": [ + 295, + 732, + 314, + 742 + ], + "type": "text", + "content": "3861" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 68, + 242, + 281 + ], + "blocks": [ + { + "bbox": [ + 49, + 68, + 242, + 281 + ], + "lines": [ + { + "bbox": [ + 49, + 68, + 242, + 281 + ], + "spans": [ + { + "bbox": [ + 49, + 68, + 242, + 281 + ], + "type": "image", + "image_path": "32f761e924347836ca27401d5c09e7df302aec3f4171515ac4a5a774f87e7248.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 287, + 546, + 335 + ], + "lines": [ + { + "bbox": [ + 46, + 287, + 546, + 335 + ], + "spans": [ + { + "bbox": [ + 46, + 287, + 546, + 335 + ], + "type": "text", + "content": "Figure 2: We visualize the loss functions used to train our method. The dynamics function is trained via reconstruction loss in embedding space (left). The distance function is trained via contrastive learning, with positive anchors chosen by predicting the next state using the ground truth action, " + }, + { + "bbox": [ + 46, + 287, + 546, + 335 + ], + "type": "inline_equation", + "content": "F(i_{t},a_{t})" + }, + { + "bbox": [ + 46, + 287, + 546, + 335 + ], + "type": "text", + "content": ", and predicting negative pairs chosen using noisy actions " + }, + { + "bbox": [ + 46, + 287, + 546, + 335 + ], + "type": "inline_equation", + "content": "F(i_{t},\\hat{a}^{j})" + }, + { + "bbox": [ + 46, + 287, + 546, + 335 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 244, + 68, + 545, + 277 + ], + "blocks": [ + { + "bbox": [ + 244, + 68, + 545, + 277 + ], + "lines": [ + { + "bbox": [ + 244, + 68, + 545, + 277 + ], + "spans": [ + { + "bbox": [ + 244, + 68, + 545, + 277 + ], + "type": "image", + "image_path": "e72a925803eadf711bbeeaba45553b5648caa668defcebe0c95d8ffda2fdb103.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "spans": [ + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "content": "robot hardware. Thus, we develop a simple inference policy that solves for robot actions using our learned distance and dynamics function. First, a cost function " + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "inline_equation", + "content": "C_g(i) = d(i,i_g)" + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "content": " is parameterized given a goal observation " + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "inline_equation", + "content": "I_{g}" + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "content": " and the learned distance function. " + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "inline_equation", + "content": "C_g" + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "content": " encodes how far an arbitrary image observation is from the goal image. The optimal action, " + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "inline_equation", + "content": "a_{t}^{*}" + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "content": ", will take the robot closest to the goal, hence: " + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "inline_equation", + "content": "a_{t}^{*} = \\mathbf{argmin}_{a}C_{g}(F(i_{t},a))" + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "content": ". Note that we use the dynamics function " + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "content": " to predict the next state, since we do not know the real " + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "inline_equation", + "content": "i_{t + 1}^{*}" + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "content": " during test time. The cost minimization is performed using the shooting method: random candidate actions, " + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "inline_equation", + "content": "a_1,\\ldots ,a_N" + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "content": ", are sampled from " + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "content": ", passed through the dynamics function, and the action with minimum cost " + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "inline_equation", + "content": "C_g(F(i_t,a_i))" + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "content": " is executed on the robot. This process is illustrated in Fig. 1. Policy execution ends once the distance between the current state and the goal falls below a threshold value: " + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "inline_equation", + "content": "C_g(i_t) < \\lambda" + }, + { + "bbox": [ + 46, + 357, + 289, + 609 + ], + "type": "text", + "content": ". While a more complicated planner could've been used, this solution was adopted due to its speed, simplicity, lack of hyperparameters, and good empirical performance." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "text", + "content": "The final detail to discuss is gripper control for prehensile tasks (e.g. pick and place). Since the gripper status is binary (open/close) and highly correlated with the current state (i.e. close when object in hand), it makes more sense to handle it implicitly rather than as part of the action command " + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "inline_equation", + "content": "a_{t}" + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "text", + "content": ". Thus, we trained a gripper action classifier " + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{G}(i_t)\\in [0,1]" + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "text", + "content": " that predicts the probability of closing the gripper given the current" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 357, + 546, + 440 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 357, + 546, + 440 + ], + "spans": [ + { + "bbox": [ + 304, + 357, + 546, + 440 + ], + "type": "text", + "content": "image embedding. This is also implemented by adding a single layer to ResNet-18 initialized by R3M weights and can be trained using a small amount " + }, + { + "bbox": [ + 304, + 357, + 546, + 440 + ], + "type": "inline_equation", + "content": "(< 100)" + }, + { + "bbox": [ + 304, + 357, + 546, + 440 + ], + "type": "text", + "content": " of human labelled images from the train dataset " + }, + { + "bbox": [ + 304, + 357, + 546, + 440 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 304, + 357, + 546, + 440 + ], + "type": "text", + "content": ". As a result, our system can seamlessly handle gripper control in prehensile tasks, without requiring gripper labels for every frame in " + }, + { + "bbox": [ + 304, + 357, + 546, + 440 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 304, + 357, + 546, + 440 + ], + "type": "text", + "content": "!" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 450, + 441, + 464 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 450, + 441, + 464 + ], + "spans": [ + { + "bbox": [ + 306, + 450, + 441, + 464 + ], + "type": "text", + "content": "4. Experimental Setup" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 471, + 547, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 471, + 547, + 590 + ], + "spans": [ + { + "bbox": [ + 304, + 471, + 547, + 590 + ], + "type": "text", + "content": "Our method is tested on four different manipulation tasks (see Fig. 3) that require a mix of high-level reasoning (e.g. go to object before target), low level precision (must carefully grab knob to turn it), and time-time generalization (e.g. push novel object). We collect behavior data for each task from human demonstrators as described below. The trained policies are deployed on a real Franka Pandas robot (see Fig. 4, right). Additional details on the hardware setup and control stack are presented in Supplement B.1." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 597, + 354, + 609 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 597, + 354, + 609 + ], + "spans": [ + { + "bbox": [ + 306, + 597, + 354, + 609 + ], + "type": "text", + "content": "4.1. Tasks" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 616, + 545, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 616, + 545, + 651 + ], + "spans": [ + { + "bbox": [ + 306, + 616, + 545, + 651 + ], + "type": "text", + "content": "We now introduce the tasks used in our experiments (pictured in Fig. 3), and provide more details on their train and test conditions:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "content": "Pushing For this task (see Fig. 3a) the robot must approach a novel object placed on the table and push it to the goal location (marked by target printout). Training: Our method was trained on a dataset of" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "spans": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "type": "text", + "content": "3862" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 52, + 70, + 172, + 161 + ], + "blocks": [ + { + "bbox": [ + 52, + 70, + 172, + 161 + ], + "lines": [ + { + "bbox": [ + 52, + 70, + 172, + 161 + ], + "spans": [ + { + "bbox": [ + 52, + 70, + 172, + 161 + ], + "type": "image", + "image_path": "35a211cc8cb76b0991a26470b1cd2874927bded007aee8718ee9872a7c06c8ce.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 88, + 169, + 137, + 180 + ], + "lines": [ + { + "bbox": [ + 88, + 169, + 137, + 180 + ], + "spans": [ + { + "bbox": [ + 88, + 169, + 137, + 180 + ], + "type": "text", + "content": "(a) Pushing" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 173, + 70, + 294, + 161 + ], + "blocks": [ + { + "bbox": [ + 173, + 70, + 294, + 161 + ], + "lines": [ + { + "bbox": [ + 173, + 70, + 294, + 161 + ], + "spans": [ + { + "bbox": [ + 173, + 70, + 294, + 161 + ], + "type": "image", + "image_path": "47d95f914e85a5422d588c3490040c63cd4d8567afd47eed5d3035afd28fa48c.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 196, + 169, + 272, + 179 + ], + "lines": [ + { + "bbox": [ + 196, + 169, + 272, + 179 + ], + "spans": [ + { + "bbox": [ + 196, + 169, + 272, + 179 + ], + "type": "text", + "content": "(b) Pick and Place" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 186, + 546, + 222 + ], + "lines": [ + { + "bbox": [ + 46, + 186, + 546, + 222 + ], + "spans": [ + { + "bbox": [ + 46, + 186, + 546, + 222 + ], + "type": "text", + "content": "Figure 3: Our method is tested on 4 different manipulation tasks (pictured above). These tasks test different skill axis, ranging from task-level reasoning (e.g. detect target, move to object before goal, etc.) to fine-grained motor control (e.g. grab top of knob to turn)." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 295, + 70, + 416, + 161 + ], + "blocks": [ + { + "bbox": [ + 295, + 70, + 416, + 161 + ], + "lines": [ + { + "bbox": [ + 295, + 70, + 416, + 161 + ], + "spans": [ + { + "bbox": [ + 295, + 70, + 416, + 161 + ], + "type": "image", + "image_path": "7a835bb50752f27737dfb01a7e97828ac3ccc28fbe9827a599d4760db54f73b3.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 320, + 169, + 393, + 180 + ], + "lines": [ + { + "bbox": [ + 320, + 169, + 393, + 180 + ], + "spans": [ + { + "bbox": [ + 320, + 169, + 393, + 180 + ], + "type": "text", + "content": "(c) Door Opening" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 417, + 70, + 539, + 161 + ], + "blocks": [ + { + "bbox": [ + 417, + 70, + 539, + 161 + ], + "lines": [ + { + "bbox": [ + 417, + 70, + 539, + 161 + ], + "spans": [ + { + "bbox": [ + 417, + 70, + 539, + 161 + ], + "type": "image", + "image_path": "d7899741b36d8f2259b203af305fe17a144a3690eaae68b6b571561702b70fd2.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 442, + 169, + 515, + 180 + ], + "lines": [ + { + "bbox": [ + 442, + 169, + 515, + 180 + ], + "spans": [ + { + "bbox": [ + 442, + 169, + 515, + 180 + ], + "type": "text", + "content": "(d) Knob Turning" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 48, + 259, + 288, + 370 + ], + "blocks": [ + { + "bbox": [ + 58, + 245, + 277, + 257 + ], + "lines": [ + { + "bbox": [ + 58, + 245, + 277, + 257 + ], + "spans": [ + { + "bbox": [ + 58, + 245, + 277, + 257 + ], + "type": "text", + "content": "Low-Cost Human Videos Transferred to Robot" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 48, + 259, + 288, + 370 + ], + "lines": [ + { + "bbox": [ + 48, + 259, + 288, + 370 + ], + "spans": [ + { + "bbox": [ + 48, + 259, + 288, + 370 + ], + "type": "image", + "image_path": "bd1a213a787e7f17cde1cd7006fdff6eaa84d3258431ffd949eca61a437763ac.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 379, + 287, + 452 + ], + "lines": [ + { + "bbox": [ + 46, + 379, + 287, + 452 + ], + "spans": [ + { + "bbox": [ + 46, + 379, + 287, + 452 + ], + "type": "text", + "content": "Figure 4: In our problem setting we use a low-cost reacher grabber tool (left) to collect training demonstrations. These demonstrations are used to acquire a robot controller purely through distance/representation learning. The final system is deployed on a robot (right) to solve various tasks at test-time." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 472, + 287, + 557 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 472, + 287, + 557 + ], + "spans": [ + { + "bbox": [ + 46, + 472, + 287, + 557 + ], + "type": "text", + "content": "100 demonstrations with diverse objects and randomized targets. Testing: During test time, the method was evaluated using 20 trails that involved unseen objects and new target printouts placed in randomly sampled positions. A trail is deemed successful if the robot pushes the object onto the target. This is the only task that did not require gripper control." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "type": "text", + "content": "Pick and Place This task (see Fig. 3b) is analogous to the pushing task (described above), except the robot must now pick the object up from its initial location and place it in a target bowl. This task requires more precision than pushing, since grasping an object is harder than localizing it. Training: We collect a dataset of 400 demonstrations for training, using randomized train objects and target bowls. Testing: The method is evaluated using 20 trails that used novel objects and unseen target bowls (i.e. analogous to pushing). A trail is successful if the robot places an object into the target." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 241, + 547, + 398 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 241, + 547, + 398 + ], + "spans": [ + { + "bbox": [ + 304, + 241, + 547, + 398 + ], + "type": "text", + "content": "Door Opening The opening task (see Fig. 3c) requires the robot to approach a handle, grasp it, and then pull the door open. While conceptually simple, this task requires a great deal of precision, since the commanded actions must (almost) exactly match the direction of the door hinge. Training: We created a toy kitchen setting for this task, and collected 100 demonstrations of opening the door when starting from various initial positions. Testing: We evaluated on 20 real world test trials, where the robot's initial position and the door's initial state (e.g. position and hinge angle) were randomized. A trial was deemed successful if the door is opened fully." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 411, + 547, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 411, + 547, + 544 + ], + "spans": [ + { + "bbox": [ + 304, + 411, + 547, + 544 + ], + "type": "text", + "content": "Knob Turning In this final task (see Fig. 3d) the robot must approach a knob in the toy kitchen, and then turn it clock-wise. Similar to the opening task, knob turning requires very precise motor control, since the robot must grab the knob at exactly the right location and carefully rotate in order to turn. Training: We collect a dataset of 100 knob turning demonstrations. Testing: The method is evaluated on 20 trials, with randomized robot/knob initial positions. Success is determined by if the knob is turned far enough to cause an audible \"click.\"" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 552, + 457, + 563 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 552, + 457, + 563 + ], + "spans": [ + { + "bbox": [ + 306, + 552, + 457, + 563 + ], + "type": "text", + "content": "4.2. Robot-Free Data Collection" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 570, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 547, + 715 + ], + "type": "text", + "content": "A major strength of our setup is that training data " + }, + { + "bbox": [ + 304, + 570, + 547, + 715 + ], + "type": "inline_equation", + "content": "(\\mathcal{D})" + }, + { + "bbox": [ + 304, + 570, + 547, + 715 + ], + "type": "text", + "content": " can come from a different agent than the test time robot. We leverage this property to collect videos directly from humans operating a low-cost grabber stick (see Fig. 4, left), and use structure from motion [38] to recover actions. This allows us to collect demonstrations without an expensive tele-op setup [50, 23] or time-intensive kinesthetic demonstrations (i.e. manually moving the robot by hand). While based on prior work, our stick setup makes two important contributions: it is easier build and use than the highly instrumented setup in Song et. al. [42], and it provides higher" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "spans": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "type": "text", + "content": "3863" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 52, + 69, + 547, + 514 + ], + "blocks": [ + { + "bbox": [ + 52, + 69, + 547, + 514 + ], + "lines": [ + { + "bbox": [ + 52, + 69, + 547, + 514 + ], + "spans": [ + { + "bbox": [ + 52, + 69, + 547, + 514 + ], + "type": "image", + "image_path": "8398b4afcf5be3c6f62a7c638a54e947fbf983308453f164d06f921b3c078d57.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 521, + 547, + 571 + ], + "lines": [ + { + "bbox": [ + 46, + 521, + 547, + 571 + ], + "spans": [ + { + "bbox": [ + 46, + 521, + 547, + 571 + ], + "type": "text", + "content": "Figure 5: Trajectories executed on the robot using our learned distance function. For each task, we show the " + }, + { + "bbox": [ + 46, + 521, + 547, + 571 + ], + "type": "inline_equation", + "content": "1^{st}" + }, + { + "bbox": [ + 46, + 521, + 547, + 571 + ], + "type": "text", + "content": " person view (top) and " + }, + { + "bbox": [ + 46, + 521, + 547, + 571 + ], + "type": "inline_equation", + "content": "3^{rd}" + }, + { + "bbox": [ + 46, + 521, + 547, + 571 + ], + "type": "text", + "content": " person view images (bottom). We show the learned visual embedding can encode functional distances between states for challenging tasks, like pushing, pick and place, door opening, and knob turning." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 591, + 288, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 591, + 288, + 641 + ], + "spans": [ + { + "bbox": [ + 46, + 591, + 288, + 641 + ], + "type": "text", + "content": "quality images and action labels than the GoPro used in Young et. al. [48]. Please refer to Supplement A.2 for more information on our training and testing setups. We will release our dataset publicly." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 655, + 140, + 670 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 655, + 140, + 670 + ], + "spans": [ + { + "bbox": [ + 47, + 655, + 140, + 670 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "content": "The following experiments seek to validate our distance learning framework on real control tasks (described above), and give some fundamental insights" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 591, + 547, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 591, + 547, + 687 + ], + "spans": [ + { + "bbox": [ + 304, + 591, + 547, + 687 + ], + "type": "text", + "content": "as to why they work. First, our baseline study (see Sec. 5.1) compares our method against representative SOTA techniques in the field. In addition, in Sec. 5.2 we analyze a specific scenario with highly multi-modal actions, where our model especially shines. Finally, the ablation study (see Sec. 5.3) investigates which components of our system are actually needed for good performance." + } + ] + } + ], + "index": 5 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "spans": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "type": "text", + "content": "3864" + } + ] + } + ], + "index": 6 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 71, + 283, + 133 + ], + "blocks": [ + { + "bbox": [ + 48, + 71, + 283, + 133 + ], + "lines": [ + { + "bbox": [ + 48, + 71, + 283, + 133 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 283, + 133 + ], + "type": "table", + "html": "
TaskOursBC [35, 48]IBC [13]IQL [20]
Pushing85%70%70%65%
Pick and Place60%30%30%45%
Door Opening55%40%45%50%
Knob Turning40%20%20%35%
", + "image_path": "9483390e884922a6ff730ef68a2153aa8d0594ef7e1a9084d875926f2607b67d.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 48, + 200, + 284, + 281 + ], + "blocks": [ + { + "bbox": [ + 46, + 141, + 287, + 191 + ], + "lines": [ + { + "bbox": [ + 46, + 141, + 287, + 191 + ], + "spans": [ + { + "bbox": [ + 46, + 141, + 287, + 191 + ], + "type": "text", + "content": "Table 1: We compare success rates for our method versus the baselines on all four manipulation tasks. Our distance learning method outperforms a suite of representative robot learning baselines." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 200, + 284, + 281 + ], + "lines": [ + { + "bbox": [ + 48, + 200, + 284, + 281 + ], + "spans": [ + { + "bbox": [ + 48, + 200, + 284, + 281 + ], + "type": "table", + "html": "
# DemosPushingPick and Place
OursBCIBCOursBCIBC
5070%50%40%0%0%0%
10085%70%70%10%10%0%
20090%80%100%20%20%10%
400100%100%100%60%30%30%
600100%100%100%70%50%40%
", + "image_path": "5fd876afc676a6c143269ecf5e3dce3942a7b5051e824604a7818fae6f8c1ff9.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 289, + 287, + 350 + ], + "lines": [ + { + "bbox": [ + 46, + 289, + 287, + 350 + ], + "spans": [ + { + "bbox": [ + 46, + 289, + 287, + 350 + ], + "type": "text", + "content": "Table 2: We compare our distance learning method versus the behavior cloning baselines (BC [35, 48] and IBC [13]) when trained on varying amounts of data. Distance learning is able to learn faster than the baselines and scale better with data." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 47, + 370, + 139, + 383 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 370, + 139, + 383 + ], + "spans": [ + { + "bbox": [ + 47, + 370, + 139, + 383 + ], + "type": "text", + "content": "5.1. Baseline Study" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 388, + 287, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 388, + 287, + 521 + ], + "spans": [ + { + "bbox": [ + 46, + 388, + 287, + 521 + ], + "type": "text", + "content": "We first note that our paper uses only demonstration data and no online data. Therefore, we compare our method against three SOTA baselines - ranging from standard behavior cloning, to energy based modeling, and Offline Reinforcement Learning (RL) - that cover a wide range of prior LfD work. The baseline methods are described briefly below. To make the comparisons fair, we parameterize all neural networks with the same R3M representation backbone used by our method, and tune hyper-parameters for best possible performance. Please check Supplement B.2 for in depth details." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 57, + 529, + 287, + 715 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 57, + 529, + 287, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 529, + 287, + 602 + ], + "spans": [ + { + "bbox": [ + 57, + 529, + 287, + 602 + ], + "type": "text", + "content": "- Behavior Cloning [35, 48] (BC): BC learns a policy (via regression) that directly predicts actions from image observations: " + }, + { + "bbox": [ + 57, + 529, + 287, + 602 + ], + "type": "inline_equation", + "content": "\\min_{\\pi}||\\pi(I_t,I_g) - a_t||_2" + }, + { + "bbox": [ + 57, + 529, + 287, + 602 + ], + "type": "text", + "content": ". This provides a strong comparison point for a whole class of LfD methods that focus on learning motor policies directly." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 57, + 609, + 287, + 694 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 609, + 287, + 694 + ], + "spans": [ + { + "bbox": [ + 57, + 609, + 287, + 694 + ], + "type": "text", + "content": "- Implicit Behavior Cloning [13] (IBC): IBC learns an energy based model that can predict actions during test time via optimization: " + }, + { + "bbox": [ + 57, + 609, + 287, + 694 + ], + "type": "inline_equation", + "content": "a_{t} = \\operatorname{argmin}_{a} E(a, I_{t}, I_{g})" + }, + { + "bbox": [ + 57, + 609, + 287, + 694 + ], + "type": "text", + "content": ". This method is conceptually very similar to behavior cloning, but has the potential to better handle multi-modal action distributions and discontinuous actions." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 57, + 700, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 700, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 57, + 700, + 287, + 715 + ], + "type": "text", + "content": "- Implicit Q-Learning [20] (IQL): IQL is an" + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 324, + 72, + 545, + 180 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 324, + 72, + 545, + 180 + ], + "spans": [ + { + "bbox": [ + 324, + 72, + 545, + 180 + ], + "type": "text", + "content": "offline-RL baseline that learns a Q function " + }, + { + "bbox": [ + 324, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "Q(s,a) = Q((I_t,I_g),a_t)" + }, + { + "bbox": [ + 324, + 72, + 545, + 180 + ], + "type": "text", + "content": ", alongside a policy that maximizes it " + }, + { + "bbox": [ + 324, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "\\pi (I_t,I_g) = \\arg \\max_aQ(s,a)" + }, + { + "bbox": [ + 324, + 72, + 545, + 180 + ], + "type": "text", + "content": ". Note that IQL's training process requires us to annotate our offline trajectories " + }, + { + "bbox": [ + 324, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 324, + 72, + 545, + 180 + ], + "type": "text", + "content": " with a reward signal " + }, + { + "bbox": [ + 324, + 72, + 545, + 180 + ], + "type": "inline_equation", + "content": "r_t" + }, + { + "bbox": [ + 324, + 72, + 545, + 180 + ], + "type": "text", + "content": " for each time-step. While this can be done automatically in our setting (Supplement B.2), this is an additional assumption that could be very burdensome in the general case." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 186, + 547, + 307 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 186, + 547, + 307 + ], + "spans": [ + { + "bbox": [ + 304, + 186, + 547, + 307 + ], + "type": "text", + "content": "Our method is compared against the baselines on all four of our tasks (see Sec. 4.1). Results are reported in Table 1. Note how our distance learning approach achieves the highest success rates on all of four tasks. In addition, our method is much simpler than the strongest baseline (IQL), which requires an expert defined reward signal and uses a more complicated learning algorithm. The final test time performance is visualized in Fig. 5 and on our website: https://agilabs.github.io/manipulate-by-seeing/." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 318, + 547, + 450 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 318, + 547, + 450 + ], + "spans": [ + { + "bbox": [ + 304, + 318, + 547, + 450 + ], + "type": "text", + "content": "Data Scaling A common cited strength of BC (versus RL) is its ability to continuously improve with additional expert data. Can our method do the same? Table 2 compares our distance learning method versus the BC/IBC baselines (on pushing/pick-place tasks), when trained on various amounts of data. Note how our method both learns faster than BC/IBC, and continuously scales with added demonstrations. This suggests that distance learning is a powerful alternative to BC on robotic manipulation tasks, no matter how much training data is available." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 456, + 460, + 468 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 456, + 460, + 468 + ], + "spans": [ + { + "bbox": [ + 306, + 456, + 460, + 468 + ], + "type": "text", + "content": "5.2. Multi-Modality Experiment" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 474, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 474, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 474, + 545, + 713 + ], + "type": "text", + "content": "A common challenge in policy learning is effectively handling multi-modal action predictions. We propose a simple test scenario that allows us to test our method in this setting without any other confounding variables. Specifically, we create a \"obstacle pushing\" task where the robot must push an object to the target without disturbing an obstacle placed in the middle (see Fig. 6). Observe that there are two equally valid ways that the robot could push the block; to the left or to the right. We collect a training dataset of 100 demos, equally split between going left and right. This creates action multi-modality where the agent must arbitrarily choose between two scenarios in order to successfully perform the task, but will fail if it simply averages the actions and pushes the block forward (into the obstacle). We expect that standard BC will fall into this failure mode, since it is trained using standard L2 action regression. In contrast, our method should still work since the low distance states will move the robot either to the left or right state, thus allowing it to make a discrete choice." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "spans": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "type": "text", + "content": "3865" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 72, + 71, + 261, + 260 + ], + "blocks": [ + { + "bbox": [ + 72, + 71, + 261, + 260 + ], + "lines": [ + { + "bbox": [ + 72, + 71, + 261, + 260 + ], + "spans": [ + { + "bbox": [ + 72, + 71, + 261, + 260 + ], + "type": "image", + "image_path": "eee2abf71c645549d93ea0e946d29a3a02e616b71efbba8900beafd4e890dd0d.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 269, + 287, + 342 + ], + "lines": [ + { + "bbox": [ + 46, + 269, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 46, + 269, + 287, + 342 + ], + "type": "text", + "content": "Figure 6: Our method can solve tasks with highly multi-modal action distributions that are difficult for the baselines. In this example, our distance learning controller successfully pushes the block around the obstacle, while Behavior Cloning learns to incorrectly push the block forward (i.e. predicts mean action)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 363, + 287, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 363, + 287, + 529 + ], + "spans": [ + { + "bbox": [ + 46, + 363, + 287, + 529 + ], + "type": "text", + "content": "To verify this hypothesis, we test our method, the BC baseline, and IQL (the strongest non-BC baseline) on 20 trials in this task setting. Success is judged similarly as to pushing (see Sec. 4.1), with the added condition that the robot should not push the obstacles into the target. Our method achieves a " + }, + { + "bbox": [ + 46, + 363, + 287, + 529 + ], + "type": "inline_equation", + "content": "95\\%" + }, + { + "bbox": [ + 46, + 363, + 287, + 529 + ], + "type": "text", + "content": " success rate, versus " + }, + { + "bbox": [ + 46, + 363, + 287, + 529 + ], + "type": "inline_equation", + "content": "0\\%" + }, + { + "bbox": [ + 46, + 363, + 287, + 529 + ], + "type": "text", + "content": " for BC and " + }, + { + "bbox": [ + 46, + 363, + 287, + 529 + ], + "type": "inline_equation", + "content": "90\\%" + }, + { + "bbox": [ + 46, + 363, + 287, + 529 + ], + "type": "text", + "content": " for IQL in this setting! As expected, our method is able to greatly improve upon BC in this setting, because it explicitly avoids action prediction. While IQL should not suffer as badly from multi-modality, thanks to its learned value function, our method is still able to outperform it despite being simpler algorithmically and trained without reward signal." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 539, + 140, + 552 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 539, + 140, + 552 + ], + "spans": [ + { + "bbox": [ + 47, + 539, + 140, + 552 + ], + "type": "text", + "content": "5.3. Ablation Study" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 558, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 558, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 558, + 287, + 715 + ], + "type": "text", + "content": "Our final experiment removes components of our method in order to determine which parts were most crucial for control performance. The representation ablation replaces the R3M backbone in our neural network with a pre-trained ImageNet representation (using same ResNet-18 architecture for both). We expect the ImageNet weights to be weaker, since they were trained on a smaller dataset that did not include egocentric videos (ImageNet vs Ego4D used by R3M). Additionally, the dynamics ablation removes the dynamics module during training, thus leaving the distance model/embeddings without any physical grounding. This is similar to the method from Hahn et. al. [15] (see" + } + ] + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 307, + 71, + 542, + 129 + ], + "blocks": [ + { + "bbox": [ + 307, + 71, + 542, + 129 + ], + "lines": [ + { + "bbox": [ + 307, + 71, + 542, + 129 + ], + "spans": [ + { + "bbox": [ + 307, + 71, + 542, + 129 + ], + "type": "table", + "html": "
OursImageNet Repr.No Dynamics [15]
Pushing90%40%60%
Pick and Place60%40%35%
Door Opening55%45%50%
Knob Turning40%15%40%
", + "image_path": "a0ec1a5ede47a1b7f02678a1c6a7b61553a2dd654ddc389933dcac40ea4815a4.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 139, + 545, + 198 + ], + "lines": [ + { + "bbox": [ + 304, + 139, + 545, + 198 + ], + "spans": [ + { + "bbox": [ + 304, + 139, + 545, + 198 + ], + "type": "text", + "content": "Table 3: This table compares success rates for our method versus the ablations on the all four tasks. As you can see, removing the dynamics module from our method during training and training with a weaker representation both result in worse performance." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 220, + 545, + 269 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 220, + 545, + 269 + ], + "spans": [ + { + "bbox": [ + 304, + 220, + 545, + 269 + ], + "type": "text", + "content": "Sec. 2), with an added dynamics module. We expect this ablation to perform worse on manipulation tasks, because dynamics is more important in this setting v.s. visual navigation." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 269, + 545, + 400 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 269, + 545, + 400 + ], + "spans": [ + { + "bbox": [ + 304, + 269, + 545, + 400 + ], + "type": "text", + "content": "The two ablations are evaluated and compared against our method on all four test tasks (see Table 3). We find that our method strongly outperforms both of our baselines, which suggests that our intuition outline above is correct. In particular, we conclude that stronger representations can directly stronger control performance using our method. Additionally, this shows that the dynamics grounding is important to ensure that our learned distances transfer onto real robot hardware during test time, especially in manipulation tasks that involve object interactions/contact." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 413, + 385, + 426 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 413, + 385, + 426 + ], + "spans": [ + { + "bbox": [ + 306, + 413, + 385, + 426 + ], + "type": "text", + "content": "6. Discussion" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 434, + 545, + 637 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 434, + 545, + 637 + ], + "spans": [ + { + "bbox": [ + 304, + 434, + 545, + 637 + ], + "type": "text", + "content": "This paper demonstrates that neural image representations can be more than just state representations: a simple metric defined within the embedding space can help infer robot actions. We leverage this insight to learn a distance function and dynamics function using minimal low-cost human data. These modules parameterize a robotic planner that is validated across 4 representative manipulation tasks. Despite its simplicity, our method is able to outperform standard imitation learning and offline-RL methods in the robot learning field. This is especially true in situations involving multi-modal action distributions, where our method entirely outclasses a standard BC baseline. Finally, the ablation study demonstrates that stronger representations directly result in stronger control performance, and that dynamics grounding is important for our scheme to work in practice." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 653, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 715 + ], + "type": "text", + "content": "Future Work We hope that this paper inspires future work in the space of representation learning and robotics. Follow up works should improve visual representations specifically for robotics, by more precisely capturing fine-grained interactions between gripper/-" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "spans": [ + { + "bbox": [ + 295, + 732, + 315, + 742 + ], + "type": "text", + "content": "3866" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "text", + "content": "hand and objects. This could improve performance on tasks like knob turning, where the pre-trained R3M encoder often struggled to detect small shifts of the gripper relative to the knob. We also hope that our contrastive learning method could be extended to learn entirely without action labels. This would allow us to train on large scale manipulation datasets (e.g. YouTube videos) and transfer the results directly to the control setting. Finally, it would be ideal if data collected using our low-cost stick (see Fig. 4) could be used with a stronger, more reliable (commercial) gripper, despite the domain gap. This would enable us to solve more tasks during test time." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 240, + 113, + 252 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 240, + 113, + 252 + ], + "spans": [ + { + "bbox": [ + 48, + 240, + 113, + 252 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 260, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 53, + 260, + 287, + 304 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 260, + 287, + 304 + ], + "spans": [ + { + "bbox": [ + 53, + 260, + 287, + 304 + ], + "type": "text", + "content": "[1] Pieter Abbeel and Andrew Y Ng. Apprenticeship learning via inverse reinforcement learning. In Proceedings of the twenty-first international conference on Machine learning, page 1, 2004." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 306, + 288, + 372 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 306, + 288, + 372 + ], + "spans": [ + { + "bbox": [ + 53, + 306, + 288, + 372 + ], + "type": "text", + "content": "[2] OpenAI: Marcin Andrychowicz, Bowen Baker, Maciek Chociej, Rafal Jozefowicz, Bob McGrew, Jakub Pachocki, Arthur Petron, Matthias Plappert, Glenn Powell, Alex Ray, et al. Learning dexterous in-hand manipulation. The International Journal of Robotics Research, 39(1):3-20, 2020." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 54, + 373, + 288, + 417 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 373, + 288, + 417 + ], + "spans": [ + { + "bbox": [ + 54, + 373, + 288, + 417 + ], + "type": "text", + "content": "[3] Daniel Angelov, Yordan Hristov, Michael Burke, and Subramanian Ramamoorthy. Composing diverse policies for temporally extended tasks. IEEE Robotics and Automation Letters, 5(2):2658-2665, 2020." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 54, + 418, + 287, + 462 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 418, + 287, + 462 + ], + "spans": [ + { + "bbox": [ + 54, + 418, + 287, + 462 + ], + "type": "text", + "content": "[4] Brenna D Argall, Sonia Chernova, Manuela Veloso, and Brett Browning. A survey of robot learning from demonstration. Robotics and autonomous systems, 57(5):469-483, 2009." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 54, + 464, + 287, + 508 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 464, + 287, + 508 + ], + "spans": [ + { + "bbox": [ + 54, + 464, + 287, + 508 + ], + "type": "text", + "content": "[5] Yusuf Aytar, Tobias Pfaff, David Budden, Thomas Paine, Ziyu Wang, and Nando De Freitas. Playing hard exploration games by watching youtube. Advances in neural information processing systems, 31, 2018." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 54, + 510, + 286, + 532 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 510, + 286, + 532 + ], + "spans": [ + { + "bbox": [ + 54, + 510, + 286, + 532 + ], + "type": "text", + "content": "[6] Shikhar Bahl, Abhinav Gupta, and Deepak Pathak. Human-to-robot imitation in the wild. RSS, 2022." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 54, + 533, + 286, + 577 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 533, + 286, + 577 + ], + "spans": [ + { + "bbox": [ + 54, + 533, + 286, + 577 + ], + "type": "text", + "content": "[7] Aude Billard, Sylvain Calinon, Ruediger Dillmann, and Stefan Schaal. Survey: Robot programming by demonstration. Handbook of robotics, 59(BOOK_CHAP), 2008." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 578, + 286, + 621 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 578, + 286, + 621 + ], + "spans": [ + { + "bbox": [ + 53, + 578, + 286, + 621 + ], + "type": "text", + "content": "[8] Annie S Chen, Suraj Nair, and Chelsea Finn. Learning generalizable robotic reward functions from\" in-the-wild\" human videos. arXiv preprint arXiv:2103.16817, 2021." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 624, + 286, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 624, + 286, + 689 + ], + "spans": [ + { + "bbox": [ + 53, + 624, + 286, + 689 + ], + "type": "text", + "content": "[9] Lili Chen, Kevin Lu, Aravind Rajeswaran, Kimin Lee, Aditya Grover, Misha Laskin, Pieter Abbeel, Aravind Srinivas, and Igor Mordatch. Decision transformer: Reinforcement learning via sequence modeling. Advances in neural information processing systems, 34:15084-15097, 2021." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 691, + 286, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 286, + 713 + ], + "type": "text", + "content": "[10] Sudeep Dasari and Abhinav Gupta. Transformers for one-shot imitation learning. In CoRL 2020, 2020." + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 26, + "blocks": [ + { + "bbox": [ + 308, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 308, + 73, + 545, + 116 + ], + "type": "text", + "content": "[11] Sudeep Dasari, Abhinav Gupta, and Vikash Kumar. Learning dexterous manipulation from exemplar object trajectories and pre-grasps. In IEEE International Conference on Robotics and Automation 2023, 2023." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 308, + 118, + 545, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 118, + 545, + 173 + ], + "spans": [ + { + "bbox": [ + 308, + 118, + 545, + 173 + ], + "type": "text", + "content": "[12] Sudeep Dasari, Jianren Wang, Joyce Hong, Shikhar Bahl, Yixin Lin, Austin Wang, Abitha Thankaraj, Karanbir Chahal, Berk Calli, Saurabh Gupta, et al. Rb2: Robotic manipulation benchmarking with a twist. arXiv preprint arXiv:2203.08098, 2022." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 308, + 175, + 545, + 229 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 175, + 545, + 229 + ], + "spans": [ + { + "bbox": [ + 308, + 175, + 545, + 229 + ], + "type": "text", + "content": "[13] Pete Florence, Corey Lynch, Andy Zeng, Oscar Ramirez, Ayzaan Wahid, Laura Downs, Adrian Wong, Johnny Lee, Igor Mordatch, and Jonathan Tompson. Implicit behavioral cloning. Conference on Robot Learning (CoRL), 2021." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 231, + 545, + 306 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 231, + 545, + 306 + ], + "spans": [ + { + "bbox": [ + 308, + 231, + 545, + 306 + ], + "type": "text", + "content": "[14] Kristen Grauman, Andrew Westbury, Eugene Byrne, Zachary Chavis, Antonino Furnari, Rohit Girdhar, Jackson Hamburger, Hao Jiang, Miao Liu, Xingyu Liu, et al. Ego4d: Around the world in 3,000 hours of egocentric video. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18995-19012, 2022." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 308, + 545, + 363 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 308, + 545, + 363 + ], + "spans": [ + { + "bbox": [ + 308, + 308, + 545, + 363 + ], + "type": "text", + "content": "[15] Meera Hahn, Devendra Singh Chaplot, Shubham Tulsiani, Mustafa Mukadam, James M Rehg, and Abhinav Gupta. No rl, no simulation: Learning to navigate without navigating. Advances in Neural Information Processing Systems, 34:26661-26673, 2021." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 365, + 545, + 441 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 365, + 545, + 441 + ], + "spans": [ + { + "bbox": [ + 308, + 365, + 545, + 441 + ], + "type": "text", + "content": "[16] Ankur Handa, Arthur Allshire, Viktor Makoviychuk, Aleksei Petrenko, Ritvik Singh, Jingzhou Liu, Denys Makoviichuk, Karl Van Wyk, Alexander Zhurkevich, Balakumar Sundaralingam, Yashraj Narang, Jean-Francois Lafleche, Dieter Fox, and Gavriel State. Dextreme: Transfer of agile in-hand manipulation from simulation to reality. arXiv, 2022." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 443, + 545, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 443, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 308, + 443, + 545, + 487 + ], + "type": "text", + "content": "[17] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 487, + 545, + 542 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 487, + 545, + 542 + ], + "spans": [ + { + "bbox": [ + 308, + 487, + 545, + 542 + ], + "type": "text", + "content": "[18] Eric Jang, Alex Irpan, Mohi Khansari, Daniel Kappler, Frederik Ebert, Corey Lynch, Sergey Levine, and Chelsea Finn. Bc-z: Zero-shot task generalization with robotic imitation learning. In Conference on Robot Learning, pages 991-1002. PMLR, 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 544, + 545, + 576 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 544, + 545, + 576 + ], + "spans": [ + { + "bbox": [ + 308, + 544, + 545, + 576 + ], + "type": "text", + "content": "[19] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 578, + 545, + 610 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 578, + 545, + 610 + ], + "spans": [ + { + "bbox": [ + 308, + 578, + 545, + 610 + ], + "type": "text", + "content": "[20] Ilya Kostrikov, Ashvin Nair, and Sergey Levine. Offline reinforcement learning with implicit q-learning. arXiv preprint arXiv:2110.06169, 2021." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 612, + 545, + 656 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 612, + 545, + 656 + ], + "spans": [ + { + "bbox": [ + 308, + 612, + 545, + 656 + ], + "type": "text", + "content": "[21] Aviral Kumar, Rishabh Agarwal, Dibya Ghosh, and Sergey Levine. Implicit under-parameterization inhibits data-efficient deep reinforcement learning. arXiv preprint arXiv:2010.14498, 2020." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 658, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 658, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 658, + 545, + 689 + ], + "type": "text", + "content": "[22] Ashish Kumar, Zipeng Fu, Deepak Pathak, and Jitendra Malik. Rma: Rapid motor adaptation for legged robots. arXiv preprint arXiv:2107.04034, 2021." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "text", + "content": "[23] Vikash Kumar and Emanuel Todorov. Mujoco haptix: A virtual reality system for hand manipulation. In" + } + ] + } + ], + "index": 25 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 733, + 315, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 733, + 315, + 742 + ], + "spans": [ + { + "bbox": [ + 295, + 733, + 315, + 742 + ], + "type": "text", + "content": "3867" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 105 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 105 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 105 + ], + "type": "text", + "content": "Humanoid Robots (Humanoids), 2015 IEEE-RAS 15th International Conference on, pages 657-663. IEEE, 2015." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 106, + 287, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 106, + 287, + 149 + ], + "spans": [ + { + "bbox": [ + 48, + 106, + 287, + 149 + ], + "type": "text", + "content": "[24] Joonho Lee, Jemin Hwangbo, Lorenz Wellhausen, Vladlen Koltun, and Marco Hutter. Learning quadrupedal locomotion over challenging terrain. Science robotics, 5(47):eabc5986, 2020." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 150, + 288, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 150, + 288, + 194 + ], + "spans": [ + { + "bbox": [ + 49, + 150, + 288, + 194 + ], + "type": "text", + "content": "[25] Sergey Levine, Aviral Kumar, George Tucker, and Justin Fu. Offline reinforcement learning: Tutorial, review, and perspectives on open problems. arXiv preprint arXiv:2005.01643, 2020." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 194, + 288, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 194, + 288, + 228 + ], + "spans": [ + { + "bbox": [ + 49, + 194, + 288, + 228 + ], + "type": "text", + "content": "[26] Yixin Lin and Austin Wang. Polymetis: a real-time pytorch controller manager. In https://github.com/facebookresearch/polymetis, 2021." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 228, + 288, + 271 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 228, + 288, + 271 + ], + "spans": [ + { + "bbox": [ + 49, + 228, + 288, + 271 + ], + "type": "text", + "content": "[27] Corey Lynch, Mohi Khansari, Ted Xiao, Vikash Kumar, Jonathan Tompson, Sergey Levine, and Pierre Sermanet. Learning latent plans from play. In Conference on robot learning, pages 1113-1132. PMLR, 2020." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 272, + 288, + 316 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 272, + 288, + 316 + ], + "spans": [ + { + "bbox": [ + 49, + 272, + 288, + 316 + ], + "type": "text", + "content": "[28] Andriy Mnih and Koray Kavukcuoglu. Learning word embeddings efficiently with noise-contrastive estimation. Advances in neural information processing systems, 26, 2013." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 316, + 288, + 358 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 316, + 288, + 358 + ], + "spans": [ + { + "bbox": [ + 49, + 316, + 288, + 358 + ], + "type": "text", + "content": "[29] Suraj Nair, Aravind Rajeswaran, Vikash Kumar, Chelsea Finn, and Abhinav Gupta. R3m: A universal visual representation for robot manipulation. CoRL, 2022." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 360, + 288, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 360, + 288, + 392 + ], + "spans": [ + { + "bbox": [ + 49, + 360, + 288, + 392 + ], + "type": "text", + "content": "[30] Aaron van den Oord, Yazhe Li, and Oriol Vinyals. Representation learning with contrastive predictive coding. arXiv preprint arXiv:1807.03748, 2018." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 393, + 288, + 437 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 393, + 288, + 437 + ], + "spans": [ + { + "bbox": [ + 49, + 393, + 288, + 437 + ], + "type": "text", + "content": "[31] Simone Parisi, Aravind Rajeswaran, Senthil Purushwalkam, and Abhinav Gupta. The unsurprising effectiveness of pre-trained vision models for control. arXiv preprint arXiv:2203.03580, 2022." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 437, + 288, + 480 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 437, + 288, + 480 + ], + "spans": [ + { + "bbox": [ + 49, + 437, + 288, + 480 + ], + "type": "text", + "content": "[32] Ilija Radosavovic, Tete Xiao, Stephen James, Pieter Abbeel, Jitendra Malik, and Trevor Darrell. Realworld robot learning with masked visual pre-training. CoRL, 2022." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 482, + 288, + 546 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 482, + 288, + 546 + ], + "spans": [ + { + "bbox": [ + 49, + 482, + 288, + 546 + ], + "type": "text", + "content": "[33] Aravind Rajeswaran, Vikash Kumar, Abhishek Gupta, Giulia Vezzani, John Schulman, Emanuel Todorov, and Sergey Levine. Learning complex dexterous manipulation with deep reinforcement learning and demonstrations. arXiv preprint arXiv:1709.10087, 2017." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 49, + 548, + 288, + 590 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 548, + 288, + 590 + ], + "spans": [ + { + "bbox": [ + 49, + 548, + 288, + 590 + ], + "type": "text", + "content": "[34] Frank Rosenblatt. Principles of neurodynamics. perceptrons and the theory of brain mechanisms. Technical report, Cornell Aeronautical Lab Inc Buffalo NY, 1961." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 49, + 592, + 288, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 592, + 288, + 646 + ], + "spans": [ + { + "bbox": [ + 49, + 592, + 288, + 646 + ], + "type": "text", + "content": "[35] Stéphane Ross, Geoffrey Gordon, and Drew Bagnell. A reduction of imitation learning and structured prediction to no-regret online learning. In Proceedings of the fourteenth international conference on artificial intelligence and statistics, pages 627-635, 2011." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 49, + 647, + 288, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 647, + 288, + 679 + ], + "spans": [ + { + "bbox": [ + 49, + 647, + 288, + 679 + ], + "type": "text", + "content": "[36] Stefan Schaal. Is imitation learning the route to humanoid robots? Trends in cognitive sciences, 3(6):233-242, 1999." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 49, + 680, + 288, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 680, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 49, + 680, + 288, + 713 + ], + "type": "text", + "content": "[37] Karl Schmeckpeper, Oleh Rybkin, Kostas Daniilidis, Sergey Levine, and Chelsea Finn. Reinforcement learning with videos: Combining offline observations with" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 689 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "text", + "content": "interaction. In Conference on Robot Learning, pages 339-354. PMLR, 2021." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 96, + 545, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 96, + 545, + 139 + ], + "spans": [ + { + "bbox": [ + 308, + 96, + 545, + 139 + ], + "type": "text", + "content": "[38] Johannes Lutz Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In Conference on Computer Vision and Pattern Recognition (CVPR), 2016." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 141, + 545, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 141, + 545, + 206 + ], + "spans": [ + { + "bbox": [ + 308, + 141, + 545, + 206 + ], + "type": "text", + "content": "[39] Pierre Sermanet, Corey Lynch, Yevgen Chebotar, Jasmine Hsu, Eric Jang, Stefan Schaal, Sergey Levine, and Google Brain. Time-contrastive networks: Self-supervised learning from video. In 2018 IEEE international conference on robotics and automation (ICRA), pages 1134–1141. IEEE, 2018." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 207, + 545, + 240 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 207, + 545, + 240 + ], + "spans": [ + { + "bbox": [ + 308, + 207, + 545, + 240 + ], + "type": "text", + "content": "[40] Pierre Sermanet, Kelvin Xu, and Sergey Levine. Unsupervised perceptual rewards for imitation learning. arXiv preprint arXiv:1612.06699, 2016." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 241, + 545, + 296 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 241, + 545, + 296 + ], + "spans": [ + { + "bbox": [ + 308, + 241, + 545, + 296 + ], + "type": "text", + "content": "[41] Nur Muhammad Mahi Shafiullah, Zichen Jeff Cui, Ariuntuya Altanzaya, and Lerrel Pinto. Behavior transformers: Cloning " + }, + { + "bbox": [ + 308, + 241, + 545, + 296 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 308, + 241, + 545, + 296 + ], + "type": "text", + "content": " modes with one stone. In Thirty-Sixth Conference on Neural Information Processing Systems, 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 297, + 545, + 341 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 297, + 545, + 341 + ], + "spans": [ + { + "bbox": [ + 308, + 297, + 545, + 341 + ], + "type": "text", + "content": "[42] Shuran Song, Andy Zeng, Johnny Lee, and Thomas Funkhouser. Grasping in the wild: Learning 6 dof closed-loop grasping from low-cost demonstrations. Robotics and Automation Letters, 2020." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 342, + 545, + 364 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 342, + 545, + 364 + ], + "spans": [ + { + "bbox": [ + 308, + 342, + 545, + 364 + ], + "type": "text", + "content": "[43] Richard S Sutton and Andrew G Barto. Reinforcement learning: An introduction. MIT press, 2018." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 365, + 545, + 398 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 365, + 545, + 398 + ], + "spans": [ + { + "bbox": [ + 308, + 365, + 545, + 398 + ], + "type": "text", + "content": "[44] Michita Imai Takuma Seno. d3rlpy: An offline deep reinforcement library. In NeurIPS 2021 Offline Reinforcement Learning Workshop, December 2021." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 399, + 545, + 443 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 399, + 545, + 443 + ], + "spans": [ + { + "bbox": [ + 308, + 399, + 545, + 443 + ], + "type": "text", + "content": "[45] Emanuel Todorov, Tom Erez, and Yuval Tassa. Mu-joco: A physics engine for model-based control. In 2012 IEEE/RSJ international conference on intelligent robots and systems, pages 5026-5033. IEEE, 2012." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 443, + 545, + 476 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 443, + 545, + 476 + ], + "spans": [ + { + "bbox": [ + 308, + 443, + 545, + 476 + ], + "type": "text", + "content": "[46] Faraz Torabi, Garrett Warnell, and Peter Stone. Generative adversarial imitation from observation. arXiv preprint arXiv:1807.06158, 2018." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 477, + 545, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 477, + 545, + 521 + ], + "spans": [ + { + "bbox": [ + 308, + 477, + 545, + 521 + ], + "type": "text", + "content": "[47] Annie Xie, Avi Singh, Sergey Levine, and Chelsea Finn. Few-shot goal inference for visuomotor learning and planning. In Conference on Robot Learning, pages 40-52. PMLR, 2018." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 522, + 545, + 566 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 522, + 545, + 566 + ], + "spans": [ + { + "bbox": [ + 308, + 522, + 545, + 566 + ], + "type": "text", + "content": "[48] Sarah Young, Dhiraj Gandhi, Shubham Tulsiani, Abhinav Gupta, Pieter Abbeel, and Lerrel Pinto. Visual imitation made easy. In Conference on Robot Learning, pages 1992-2005. PMLR, 2021." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 567, + 545, + 622 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 567, + 545, + 622 + ], + "spans": [ + { + "bbox": [ + 308, + 567, + 545, + 622 + ], + "type": "text", + "content": "[49] Tianhe Yu, Deirdre Quillen, Zhanpeng He, Ryan Julian, Karol Hausman, Chelsea Finn, and Sergey Levine. Meta-world: A benchmark and evaluation for multi-task and meta reinforcement learning. In _Conference on Robot Learning (CoRL)_, 2019." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 622, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 622, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 622, + 545, + 689 + ], + "type": "text", + "content": "[50] Tianhao Zhang, Zoe McCarthy, Owen Jow, Dennis Lee, Xi Chen, Ken Goldberg, and Pieter Abbeel. Deep imitation learning for complex manipulation tasks from virtual reality teleoperation. In 2018 IEEE International Conference on Robotics and Automation (ICRA), pages 5628-5635. IEEE, 2018." + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 733, + 315, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 733, + 315, + 742 + ], + "spans": [ + { + "bbox": [ + 295, + 733, + 315, + 742 + ], + "type": "text", + "content": "3868" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/8472e89b-fe96-412d-8c9c-414b2c42d2f3_content_list.json b/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/8472e89b-fe96-412d-8c9c-414b2c42d2f3_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..8df4eaa8f6be4ffe55c2e8ea9b91b4636e902783 --- /dev/null +++ b/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/8472e89b-fe96-412d-8c9c-414b2c42d2f3_content_list.json @@ -0,0 +1,1242 @@ +[ + { + "type": "text", + "text": "MapFormer: Boosting Change Detection by Using Pre-change Information", + "text_level": 1, + "bbox": [ + 107, + 130, + 864, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Maximilian Bernhard, Niklas Strauß, Matthias Schubert LMU Munich, MCML", + "bbox": [ + 261, + 180, + 707, + 215 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{bernhard,strauss, schubert}@dbs.ifi.lmu.de", + "bbox": [ + 299, + 218, + 671, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 268, + 313, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Change detection in remote sensing imagery is essential for a variety of applications such as urban planning, disaster management, and climate research. However, existing methods for identifying semantically changed areas overlook the availability of semantic information in the form of existing maps describing features of the earth's surface. In this paper, we leverage this information for change detection in bi-temporal images. We show that the simple integration of the additional information via concatenation of latent representations suffices to significantly outperform state-of-the-art change detection methods. Motivated by this observation, we propose the new task of Conditional Change Detection, where pre-change semantic information is used as input next to bi-temporal images. To fully exploit the extra information, we propose MapFormer, a novel architecture based on a multi-modal feature fusion module that allows for feature processing conditioned on the available semantic information. We further employ a supervised, cross-modal contrastive loss to guide the learning of visual representations. Our approach outperforms existing change detection methods by an absolute $11.7\\%$ and $18.4\\%$ in terms of binary change IoU on DynamicEarthNet and HRSCD, respectively. Furthermore, we demonstrate the robustness of our approach to the quality of the pre-change semantic information and the absence pre-change imagery. The code is available at https://github.com/mxbh/mapformer.", + "bbox": [ + 75, + 301, + 473, + 709 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 739, + 209, + 753 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Earth observation data has become increasingly available in recent years, providing valuable insights into various fields such as climate research, disaster management, and urban planning. In the course of this, enormous efforts have been made towards creating rich semantic maps of the earth. For instance, OpenStreetMap provides vast amounts of data containing manual annotations around the globe. In addition, deep learning techniques are nowadays used to produce semantic map data at a large scale, e.g., [23]", + "bbox": [ + 75, + 763, + 468, + 902 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/e571ddac50674f8ec2c15b94217361d0051c77c0670b625f0cd376216b1dc01d.jpg", + "image_caption": [ + "Figure 1: Advantage of our approach over existing change detection methods (represented by ChangeFormer [2] here) on a sample of DynamicEarthNet [26]. Employing semantic pre-change information allows to extract better features and improves change detection quality." + ], + "image_footnote": [], + "bbox": [ + 506, + 268, + 888, + 529 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "generated building footprints for the entire African continent. As a result, we live in a world that has been extensively mapped. However, we live in a constantly changing world where the earth's surface is subject to various influences. These influences can be natural, e.g., earthquakes, extreme weather, floods, wildfires, and changes in vegetation, but also directly caused by humans, e.g., building construction, deforestation, and agriculture. In fact, the impact of civilization on our planet has never been higher than in recent years, with drastic consequences for ecosystems and wildlife [9, 24]. Therefore, monitoring changes in the earth's surface with up-to-date earth observation data is becoming increasingly important.", + "bbox": [ + 496, + 654, + 892, + 851 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In technical terms, this challenge is addressed by the task of change detection, where bi-temporal images are compared in order to segment pixels that have semanti-", + "bbox": [ + 498, + 854, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "16837", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "cally changed. Today, deep-learning-based methods for change detection achieve state-of-the-art performance [14, 15]. However, the research community so far mostly ignored the fact that existing semantic information like maps may be employed for change detection. To the best of our knowledge, semantic map information has been considered an additional input next to bi-temporal images for detecting change only for the specific task of updating road networks [3]. Although this approach is only possible if semantic information for the area of interest is available, we argue that maps are available for most parts of the world today. Alternatively, pre-trained neural networks can be used to generate a map containing the features of interest. Furthermore, when updating a map, a pre-change version of the map has to be available in the first place.", + "bbox": [ + 75, + 90, + 472, + 316 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this paper, we tap into this direction in a general way and establish the novel task of Conditional Change Detection (see Figure 1). We demonstrate that the usage of semantic information in form of a pixelwise map has a strong impact on change detection by showing that a simple baseline (concatenating bi-temporal image features and map features) is already able to outperform state-of-the-art change detection methods, which do not use semantic pre-change information. Furthermore, we propose MapFormer, a novel architecture to fully exploit the additional information. At its core, we integrate a newly designed multi-modal feature fusion module based on the idea that the pre-change semantics should dynamically influence the processing of hidden features. Additionally, we apply a supervised contrastive loss on the learned image features, guiding the image encoder during training and further improving the performance. We also show that our approach can be applied without bi-temporal imagery, detecting change by only processing a pre-change map and current imagery. We call this task Cross-modal Change Detection. We conduct experiments on the publicly available and challenging datasets DynamicEarthNet [26] and HRSCD [8].", + "bbox": [ + 75, + 318, + 472, + 648 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To sum up, our main contributions are as follows:", + "bbox": [ + 96, + 650, + 423, + 664 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We investigate the novel tasks of Conditional Change Detection and Cross-modal Change Detection and introduce simple baselines that outperform state-of-the-art change detection methods.", + "- We propose MapFormer, a novel architecture consisting of a multi-modal feature fusion module and a supervised contrastive loss, allowing us to effectively merge image features and semantic information.", + "- We conduct detailed experiments and ablations demonstrating our approach's consistent performance gains, robustness, and practicability." + ], + "bbox": [ + 94, + 671, + 467, + 833 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 76, + 845, + 218, + 859 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Change detection in remote sensing images has attracted much attention over the last years, resulting in numerous", + "bbox": [ + 76, + 869, + 467, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "publications in this field [14, 15, 19, 2, 11, 12, 33, 18, 20]. Most state-of-the-art methods employ deep learning and introduce various sophisticated ways of merging bi-temporal image features. For instance, [7] proposes a series of fully convolutional architectures for change detection that rely on different fusion mechanisms for the bi-temporal image features. Furthermore, [12] uses NestedUNet [34] in combination with channel attention. With the introduction of transformer architectures into computer vision [10, 4, 29], recent architectures for change detection also utilize attention blocks. BiT [5] was the first of these methods, combining a CNN backbone with cross-attention layers in the decoder head. Subsequently, works like CDViT [22], ChangeFormer [2], FHD [19], and Changer [11] use the attention mechanism in various forms, pushing the state-of-the-art in bi-temporal change detection even further. Our general architecture is inspired by ChangeFormer and FHD, which adopt the MiT backbone and the MLP head from SegFormer [29] and add specialized mechanisms to fuse the bi-temporal image features.", + "bbox": [ + 496, + 90, + 890, + 392 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "LEVIR-CD [6], DSIFN-CD [31], WHU [13], and S2Looking [21] are common benchmark datasets for bi-temporal change detection, where networks are provided with co-registered, bi-temporal images as input and have to predict a pixelwise, binary change mask. Recently, a new dataset for change detection has been published with DynamicEarthNet [26], which surpasses previous datasets in terms of volume and diversity. In addition, models have to predict semantic segmentation masks containing the land cover classes next to the binary change masks for this dataset. However, none of these methods or datasets consider inputs other than bi- or multi-temporal images. Thus, previous approaches ignore the fact that pre-change semantic information for the area of interest is often available. For semantic segmentation on the other hand, it has been shown that semantic maps extracted from geographic information systems (GIS) can be effectively used to improve segmentation quality [1, 16]. In a change detection setting, only for the specific task of road network extraction [3] challenged the community to come up with solutions for updating road networks when pre-change road networks are given. Consequently, their approach considers graph data as input and output. In contrast, we consider the pixelwise change detection task when pre-change semantic information in the form of a pixelwise map is available and show that this paradigm opens up exciting new possibilities.", + "bbox": [ + 496, + 393, + 890, + 785 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "3. Conditional Change Detection", + "text_level": 1, + "bbox": [ + 500, + 799, + 774, + 816 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We consider two points in time $t_1$ (pre-change) and $t_2$ (post-change). Correspondingly, we have two image versions $I^{(1)}$ and $I^{(2)}$ for the same geographic location at $t_1$ and $t_2$ , respectively. The ground-truth binary mask $b$ indicates which pixels in the images have changed semanti", + "bbox": [ + 496, + 825, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "16838", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "table", + "img_path": "images/efd761a5f26420abe3d7817f0a274122e9d9eca33fb8551894d6ce308a559f14.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
TaskInput I(1)I(2)m(1)Output b m(2)
Bi-temp. Bin. Change Det. (BCD)✓✓✓
Bi-temp. Sem. Change Det. (SCD)✓✓✓
[ new]Conditional BCD✓✓✓
[ new]Conditional SCD✓✓✓
[ new]Cross-modal BCD✓✓
[ new]Cross-modal SCD✓✓
", + "bbox": [ + 78, + 88, + 470, + 215 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Table 1: Inputs and outputs for different change detection tasks.", + "bbox": [ + 75, + 224, + 468, + 253 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "cally between $t_1$ and $t_2$ . Furthermore, we consider semantic maps $m^{(1)}$ and $m^{(2)}$ containing the semantic class $c \\in \\mathcal{C}$ for each pixel in $I^{(1)}$ and $I^{(2)}$ , respectively. Thus, $b$ can be obtained from $m^{(1)}$ and $m^{(2)}$ via a pixelwise inequality operation. As we propose new tasks in this paper (Conditional Change Detection and Cross-modal Change Detection), we provide a differentiated description of the existing and novel tasks here. An overview can be seen in Table 1.", + "bbox": [ + 75, + 281, + 468, + 402 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Existing Tasks In general, change detection tasks differ in two aspects: input and output. We can distinguish w.r.t. the output between binary and semantic change detection (BCD and SCD) for every combination of inputs. In BCD, the goal is to predict the binary change mask $\\hat{b}$ , indicating which pixels have changed semantically. SCD was recently proposed in [26] and constitutes an extension of BCD. Here, not only the binary change mask $\\hat{b}$ is predicted, but also the semantic segmentation $\\hat{m}^{(2)}$ of the post-change image $I^{(2)}$ . This allows us to tell which regions have changed and how they have changed. The corresponding evaluation metric $SCS$ proposed in [26] combines the binary change IoU $BC$ and the semantic change metric $SC$ as their arithmetic mean. The semantic change metric $SC$ is the standard mIoU from semantic segmentation, except that it is computed only on the pixels that have changed, i.e.", + "bbox": [ + 75, + 402, + 470, + 645 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nS C = \\frac {1}{| \\mathcal {C} |} \\sum_ {c \\in \\mathcal {C}} \\frac {| \\{b = 1 \\} \\cap \\{m ^ {(2)} = c \\} \\cap \\{\\hat {m} ^ {(2)} = c \\} |}{| \\{b = 1 \\} \\cap (\\{m ^ {(2)} = c \\} \\cup \\{\\hat {m} ^ {(2)} = c \\}) |},\n$$\n", + "text_format": "latex", + "bbox": [ + 81, + 654, + 464, + 693 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nB C = I o U (b, \\hat {b}) \\quad \\text {a n d} \\quad S C S = \\frac {B C + S C}{2} \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 83, + 696, + 468, + 724 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Regarding the input, the existing settings consider bi-temporal images $I^{(1)}$ and $I^{(2)}$ . Thus, we will refer to the existing tasks as bi-temporal BCD and bi-temporal SCD.", + "bbox": [ + 75, + 734, + 468, + 779 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Conditional Change Detection While the aforementioned change detection tasks assume bi-temporal images as input, semantic information in the form of a segmentation map $m^{(1)}$ at $t_1$ may be employed additionally. That is, given pre- and post-change images together with pre-change semantic information $m^{(1)}$ , the goal is to predict the binary change mask $\\hat{b}$ for Conditional BCD (as well as the semantic segmentation map $\\hat{m}^{(2)}$ for Conditional SCD).", + "bbox": [ + 75, + 780, + 470, + 901 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Cross-modal Change Detection When pre-change semantic maps are available, change detection can also be conducted without bi-temporal, but solely uni-temporal imagery. In this case, only comparing the semantic information $m^{(1)}$ and the current imagery $I^{(2)}$ can suffice to detect semantic changes. In other words, this setting corresponds to Conditional Change Detection with uni-temporal images. We call this task Cross-modal Change Detection as the change has to be detected across different modalities (semantic pre-change map and post-change image).", + "bbox": [ + 496, + 90, + 893, + 243 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4. MapFormer", + "text_level": 1, + "bbox": [ + 498, + 257, + 629, + 273 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4.1. Overall Architecture", + "text_level": 1, + "bbox": [ + 498, + 282, + 696, + 297 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To handle these new tasks, we propose a framework, which is inspired by [19, 2] (see Figure 2). We feed the images $I^{(1)}$ and $I^{(2)}$ through the same backbone to obtain multi-scale feature maps $f^{(1)}$ and $f^{(2)}$ . For each scale, we have a separate fusion module (see Section 4.2) that handles the features from $f^{(1)}$ and $f^{(2)}$ at the corresponding scale. In addition to the image features, in our setting, we also feed semantic information in the form of an encoded map $g^{(1)}$ into the fusion modules. These map features are obtained from $m^{(1)}$ via a shallow encoder (see Section 4.4). The outputs of the fusion modules are then multi-scale features $f$ , containing information of both points in time $t_1$ and $t_2$ . Thus, we can use them in a prediction head to output the binary change map $\\hat{b}$ . In terms of architecture, this prediction head is a standard semantic segmentation head [29]. Furthermore, we apply a contrastive loss on the image features $f^{(1)}$ and $f^{(2)}$ , which helps the model to learn semantically more meaningful representations (see Section 4.3).", + "bbox": [ + 496, + 306, + 892, + 578 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "For many applications, it may be interesting to determine into which semantic class a pixel has changed. In this case, we also need to derive a semantic segmentation map $\\hat{m}^{(2)}$ for $I^{(2)}$ . We can accomplish this either by feeding the unitemporal features $f^{(2)}$ into a separate head for semantic segmentation or by predicting both $\\hat{b}$ and $\\hat{m}^{(2)}$ based on the merged features $f$ . We analyze both variants in Section 5.5. Training a semantic segmentation head on uni-temporal image features also allows applying the trained model without pre-change information as we can use the predicted semantic segmentation $\\hat{m}^{(1)}$ instead of $m^{(1)}$ . Results for this setting are provided in Section 5.3. Furthermore, for Cross-modal Change Detection, the design of our fusion module (described next) enables us to omit the image features $f^{(1)}$ from $I^{(1)}$ . We evaluate this setting in Section 5.4.", + "bbox": [ + 496, + 579, + 893, + 805 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4.2. Multi-modal Feature Fusion", + "text_level": 1, + "bbox": [ + 498, + 816, + 754, + 830 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The main challenge in bi-temporal change detection is to design an effective method for fusing the bi-temporal image features. In the case of Conditional (and Cross-modal) Change Detection, we additionally have to bring together", + "bbox": [ + 496, + 839, + 893, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "16839", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/074a10110bb3b7794f64e422b247497d9e12c3d442a445a87c2155037dfc802f.jpg", + "image_caption": [ + "Figure 2: The proposed MapFormer framework consists of two main components: a novel fusion module, which combines inputs from different points in time and modalities, and a contrastive loss module, which is only used during training." + ], + "image_footnote": [], + "bbox": [ + 138, + 88, + 854, + 300 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/c49cdb411da3fc8dd0179dade9c79825fee0ef4c769bec92907a13aa3867c444.jpg", + "image_caption": [ + "Figure 3: Our multi-modal feature fusion module for fusing bi-temporal image features and semantic input features." + ], + "image_footnote": [], + "bbox": [ + 78, + 373, + 455, + 489 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "different modalities, i.e., the image features and the available semantic information. To this end, we propose a novel multi-modal feature fusion module. Subsequently, we follow [19, 29] and assume that the spatial context is encoded within the backbone, so we only consider pointwise operations, treating each spatial location separately.", + "bbox": [ + 75, + 564, + 468, + 656 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "A standard way of merging multi-modal features is a simple concatenation along the channel dimension. However, we argue that the semantic information in our setting can be used more effectively if we use it to modulate the features dynamically. Thus, the given information should influence the processing of image features and thereby improve perception. Such data-dependent feature processing can be achieved by dynamically predicting the weights of one or more layers from the features themselves [30, 25]. While such techniques are powerful, they come at a significant computational cost. In fact, applying a method like DynamicMLP [30] to a segmentation task like ours by predicting dynamic weights for each pixel separately is intractable without drastically reducing the number of channels (or the spatial resolution). Therefore, we resort to a restricted attention-style approach. More precisely, to keep", + "bbox": [ + 75, + 659, + 470, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "the computational cost tractable, we restrict the attention to a set of $K$ values for each output dimension, thereby greatly reducing the complexity compared to unrestricted attention.", + "bbox": [ + 496, + 369, + 890, + 415 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "A visualization of our proposed multi-modal feature fusion module can be seen in Figure 3. First, we concatenate the bi-temporal features $f_{(i,j)}^{(1)}$ and $f_{(i,j)}^{(2)}$ and the map feature $g_{(i,j)}^{(1)}$ for each spatial location $(i,j)$ . This concatenated feature is fed through $K$ separate MLPs (implemented with grouped, pointwise convolutions) to obtain $K$ joint representations $(h_{k(i,j)})_{k=1\\dots K}$ with $D_f$ channels. Here, $D_f$ refers to the dimensionality of $f_{(i,j)}^{(t)}, t = 1,2$ , and $K$ is a hyperparameter for tuning the semantic variety. These $K$ joint representations $(h_{k(i,j)})_{k=1\\dots K}$ can be interpreted as views, encoding different aspects of the same spatial location. To associate the map information $g_{(i,j)}^{(1)}$ with these views, we employ a channelwise attention mechanism. In particular, we compute attention weights by feeding the map features $g_{(i,j)}^{(1)}$ into an additional MLP. The result of shape $K\\times D_f$ is softmaxed over the $K$ -dimension providing a matrix of attention scores with entries $a_{(i,j,k,d)}$ for location $(i,j)$ . Thus, each channel of the module output $f_{(i,j)}$ separately attends to the $K$ joint representations $(h_{k(i,j)})_{k=1\\dots K}$ . In mathematical terms, we compute", + "bbox": [ + 496, + 416, + 892, + 734 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nf _ {(i, j)} = \\left(\\sum_ {k = 1 \\dots K} a _ {(i, j, k, d)} h _ {k (i, j, d)}\\right) _ {d = 1 \\dots D _ {f}} \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 545, + 741, + 890, + 787 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The merged features $f_{(i,j)}$ are then collected for the different scales of the backbone feature maps and passed to the prediction head.", + "bbox": [ + 496, + 792, + 890, + 839 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.3. Contrastive Loss", + "text_level": 1, + "bbox": [ + 500, + 847, + 666, + 861 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "For unchanged areas, we want $f^{(1)}, f^{(2)}$ , and $g^{(1)}$ to encode the same semantic concepts. For changed areas how-", + "bbox": [ + 496, + 869, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "16840", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "ever, the encoded information in $f^{(1)}$ and $g^{(1)}$ should be similar, while $f^{(2)}$ should be dissimilar from the two. Based on this observation, we design a supervised contrastive loss that forces the network to learn better image features. More precisely, we apply a learnable projection $\\pi$ to map $f^{(1)}$ and $f^{(2)}$ into the feature space of $g^{(1)}$ . Then, we compute our contrastive loss as follows:", + "bbox": [ + 75, + 89, + 472, + 196 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {L} _ {(i, j)} ^ {(c o n t r)} = - \\operatorname {s i m} \\left(g _ {(i, j)} ^ {(1)}, \\pi \\left(f _ {(i, j)} ^ {(1)}\\right)\\right) \\tag {3} \\\\ + \\left\\{ \\begin{array}{l l} - \\operatorname {s i m} \\left(g _ {(i, j)} ^ {(1)}, \\pi \\big (f _ {(i, j)} ^ {(2)} \\big)\\right), & b _ {(i, j)} = 0 \\\\ \\max \\left(\\operatorname {s i m} \\left(g _ {(i, j)} ^ {(1)}, \\pi \\big (f _ {(i, j)} ^ {(2)} \\big)\\right), 0\\right), & b _ {(i, j)} = 1. \\end{array} \\right. \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 76, + 199, + 472, + 275 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Here, $\\operatorname{sim}(\\cdot, \\cdot)$ denotes the cosine similarity, and the loss is ultimately aggregated over all pixel locations $(i,j)$ . Interestingly, we found it beneficial not to use a projection for $g^{(1)}$ and also not to backpropagate gradients coming from the contrastive loss through $g^{(1)}$ . Details can be found in Section 5.3.", + "bbox": [ + 75, + 279, + 470, + 369 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.4. Architecture Details", + "text_level": 1, + "bbox": [ + 76, + 377, + 267, + 392 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Like [19], we use the MixVisionTransformer from [29] as image encoder backbone. Due to the spatial attention in the encoder, the features $f_{(i,j)}^{(t)}$ are already contextualized, and a pointwise prediction head after a pointwise fusion module suffices to produce high-quality predictions. We leave SegFormer's prediction head unchanged and solely plug in our proposed feature fusion module between the backbone and the head. Thus, our module can be easily combined with other architectures. Inside our feature fusion module, the merged features $(h_k)_{k=1\\dots K}$ are produced by $K$ two-layer MLPs, while the attention weights $a$ are predicted from $g^{(1)}$ via a linear layer. To encode the semantic information $m^{(1)}$ into $g^{(1)}$ , we use a three-layer CNN with a pointwise convolution followed by two convolutions with a kernel size of five and a dilation of two to increase the receptive field. When fusing the encoded map $g^{(1)}$ , we use bilinear interpolation to comply with the different spatial resolutions of the different scales of the image feature maps. The projection head $\\pi$ for the contrastive loss is a pointwise MLP head in the style of SegFormer's prediction head. The overall training loss is the sum of our contrastive loss and the cross-entropy loss for the binary change map (as well as the semantic segmentation in SCD).", + "bbox": [ + 75, + 400, + 472, + 750 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 76, + 762, + 209, + 779 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.1. Datasets", + "text_level": 1, + "bbox": [ + 76, + 786, + 179, + 801 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Since Conditional Change Detection requires semantic segmentation maps, which are not included in commonly used benchmark datasets such as LEVIR-CD [6], DSIFN-CD [31], and S2Looking [21], we conduct our experiments on DynamicEarthNet [26] and HRSCD [8]. DynamicEarthNet is a recent dataset consisting of daily images of 75 areas", + "bbox": [ + 75, + 809, + 470, + 902 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "of interest (AOIs) over a span of two years. Ground-truth annotations containing the seven land use classes \"impervious surface\", \"agriculture\", \"forest & other vegetation\", \"wetlands\", \"soil\", \"water\", and \"snow & ice\" are only available for the first day of each month and 55 AOIs. As our setting assumes semantic information as input, we only use the images with available annotations and selected 35, 10, and 10 AOIs for training, validation, and testing, respectively. Following [26], we omit the class \"snow & ice\" from the evaluation because it only occurs in two AOIs. Targets for binary change detection were created by applying a pixelwise inequality on pairs of ground-truth semantic maps.", + "bbox": [ + 496, + 90, + 890, + 272 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The High-Resolution Semantic Change Detection (HRSCD) dataset was proposed in [8]. It contains 291 pairs of images, where the first was acquired in 2005/2006 and the second in 2012. Semantic ground-truth segmentation maps and binary change segmentation maps are available for all samples. The semantic classes are \"artificial surface\", \"agricultural area\", \"forest\", \"wetland\", and \"water\". We selected 191, 50, and 50 pairs for training, validation, and testing, respectively. Further details on both datasets can be found in the supplementary material.", + "bbox": [ + 496, + 273, + 890, + 425 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.2. Baselines", + "text_level": 1, + "bbox": [ + 500, + 438, + 607, + 452 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "As baselines derived from semantic segmentation models, we employ SegFormer [29], Swin + UPerNet [17, 28], and SETR-PUP [32] for change detection by taking the pixelwise inequality of the predicted semantic segmentations $\\hat{m}^{(1)}$ and $\\hat{m}^{(2)}$ as binary change prediction. The concatenation baseline for bi-temporal BCD resembles the SegFormer architecture, but concatenates the image features $f^{(1)}$ and $f^{(2)}$ before passing them to a head that directly predicts the binary change map. These baselines can be easily reused for Conditional BCD. For the semantic segmentation baselines, we apply the pixelwise inequality to $m^{(1)}$ and $\\hat{m}^{(2)}$ instead of $\\hat{m}^{(1)}$ and $\\hat{m}^{(2)}$ . For the concatenation baseline, we concatenate map features $g^{(1)}$ extracted by a map encoder as described in Section 4.4 to the image features $f^{(1)}$ and $f^{(2)}$ . As state-of-the-art methods for bi-temporal BCD, we select FHD [19], ChangerEx [11], and ChangeFormer [2] as they are recent and have been shown to perform best on the common benchmarks. We also extend these methods for Conditional BCD by concatenating map features to merged bi-temporal image features. Further, we consider another baseline for Conditional BCD, which has a separate concatenation-based BCD head for every semantic class such that the final change prediction can be taken from the head corresponding to the pre-change semantic class for every pixel. To have a strong competitor for our feature fusion module, we also use a pixel-wise Dynamic MLP-C [30] for fusing semantic input with image features. For training details as well as a comparison of model sizes, we refer to the supplementary material.", + "bbox": [ + 496, + 462, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "16841", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/6921e73ea79b31815e685e6221a48709c8228484b353c639b378c185c6583b28.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodDynENetHRSCD
F1IoUF1IoU
Bi-temporal BCD:
SegFormer [29]20.311.317.89.7
Swin + UPerNet [17, 28]20.111.117.69.7
SETR-PUP [32]19.410.814.88.0
Concatenation20.711.641.225.9
FHD [19]17.29.445.229.2
ChangerEx [11]21.111.837.022.7
ChangeFormer [2]20.711.545.729.6
MapFormerK=10 (w/o m(1))28.616.743.928.2
Conditional BCD:
SegFormer [29]21.211.95.62.8
Swin + UPerNet [17, 28]21.812.25.62.8
SETR-PUP [32]20.811.65.42.8
Concatenation33.520.162.145.1
FHD [19] + Concat.33.219.961.244.1
ChangerEx [11] + Concat.30.918.358.141.0
ChangeFormer [2] + Concat.31.418.661.544.4
Classwise CD-Heads37.022.762.345.3
DynamicMLP [30]34.520.862.745.7
MapFormerK=534.821.164.948.0
MapFormerK=1038.023.564.547.7
MapFormerK=1536.422.264.547.6
Ablations (MapFormerK=10):
w/o constrastive34.520.963.846.8
w/o stop-gradient36.722.562.545.4
w/ map proj.35.821.860.745.9
high-level info29.817.664.447.5
low-res. info30.417.960.343.2
", + "bbox": [ + 78, + 88, + 468, + 554 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2: (Conditional) Binary Change Detection as well as ablations. Our method performs best and is still highly competitive without ground-truth semantic input.", + "bbox": [ + 75, + 564, + 468, + 612 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.3. Binary Change Detection", + "text_level": 1, + "bbox": [ + 76, + 645, + 307, + 662 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Overall Performance In BCD, there is only a single objective (binary change IoU); thus, our approach can be best compared to other methods. In Table 2, we present BCD results for baselines, state-of-the-art methods, and our method. It is evident that Conditional BCD greatly outperforms all existing bi-temporal methods - even with the simple concatenation baseline (11.8% vs. 20.1% and 29.6% vs. 45.1% IoU, resp.). MapFormer further pushes the performance on both datasets to 23.5% and 48.0% IoU, respectively. Particularly, our method also outperforms DynamicMLP [30], a state-of-the-art method for multi-modal feature fusion. This holds for all tested values of our only hyperparameter $K$ and even without our contrastive loss (see Ablations). Remarkably, when MapFormer is applied without the true map $m^{(1)}$ , but only predicted segmentation", + "bbox": [ + 75, + 672, + 470, + 902 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "maps $\\hat{m}^{(1)}$ ( $w / o m^{(1)}$ ), the performance is still highly competitive, even achieving by far the best performance among the bi-temporal methods on DynamicEarthNet with an IoU of $16.7\\%$ . Furthermore, it is noteworthy that the semantic segmentation baselines SegFormer, Swin + UPerNet and SETR perform poorly in Conditional BCD, especially on HRSCD. We attribute this to the fact that every misclassified pixel leads to a false positive change prediction in this setup, causing a very low precision. In bi-temporal BCD, identical classification errors in $\\hat{m}^{(1)}$ and $\\hat{m}^{(2)}$ may still lead to true negative change predictions.", + "bbox": [ + 496, + 89, + 893, + 258 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Ablations In the lower part of Table 2, we present several ablation experiments to analyze MapFormer's contributing factors and robustness. First, we study the effect of our design choices in the contrastive loss module. When the contrastive loss is completely omitted (w/o contrastive), performance drops on both datasets by $2.6\\%$ and $0.9\\%$ IoU, respectively. Furthermore, we compare MapFormer with modifications where we omitted the stop-gradient operation on the map features $g^{(1)}$ (w/o stop-gradient) and a version where we included a linear projection layer to map $g^{(1)}$ to the joint embedding space with $\\pi \\left(f^{(t)}\\right)$ (w/ map proj.). Both variants do not reach the performance of our proposed method. Thus, we conclude that gradients coming from the contrastive loss flowing through the map features $g^{(1)}$ have a detrimental effect on their representation.", + "bbox": [ + 496, + 276, + 893, + 505 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Finally, we investigate the effect of the quality of the semantic information $m^{(1)}$ . To this end, we merge some classes in the pre-change maps to simulate that only high-level semantic information is available (high-level info). For DynamicEarthNet, we merge the classes \"agriculture\", \"forest & other vegetation\" and \"soil\" as well as \"wetlands\", \"water\" and \"snow & ice\" into two high-level classes, respectively. For HRSCD, we solely distinguish between \"artificial\" and \"rest\". Apparently, this high-level information still suffices to generate better change predictions than the bi-temporal change detection methods. However, we observe a significant performance drop on DynamicEarthNet (5.9% IoU), while the performance only degrades marginally on HRSCD (0.2% IoU). Furthermore, we simulate low-resolution semantic information by downsampling with a factor of 32 (low-res. info). Here, we can see that the performance of our method degrades with the low-resolution input (by 5.6% and 4.8% IoU, resp.). Nevertheless, it is still clearly superior to the bi-temporal change detection methods. In conclusion, our results show that the semantic input quality correlates to the Conditional Change Detection performance. However, low-quality input still suffices to achieve significantly better results than methods not relying on this kind of information. Further ablations can be found in the supplementary material.", + "bbox": [ + 496, + 523, + 893, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "16842", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/dfc982cb6bd2e300e3490025c0208595d212f4d590ecde0f5edfdc2a0ca1ce58.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodDynENetHRSCD
F1IoUF1IoU
SegFormer21.211.95.62.8
Swin+UPerNet21.812.25.62.8
SETR-PUP20.811.65.42.8
Concatenation31.818.961.544.4
MapFormer32.019.062.145.0
", + "bbox": [ + 78, + 88, + 352, + 200 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/40b678ad7c98b01f22cecfb240e4470b58bfa450c2d4ea18b6d93e1f189ef5e1.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodDynamicEarthNetHRSCD
BCSCSCSmIoUBCSCSCSmIoU
SegFormer11.331.521.439.79.720.315.052.7
Swin + UperNet11.128.019.641.49.720.915.353.1
SETR-PUP10.826.318.538.58.521.714.950.5
MapFormer (sem. seg. on f(2))23.029.026.039.948.021.534.752.9
MapFormer (sem. seg. on f)23.113.118.161.548.212.530.472.3
MapFormer (Cross-modal)20.430.725.540.345.621.733.549.9
", + "bbox": [ + 364, + 88, + 890, + 213 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 3: Cross-modal Binary Change Detection. MapFormer and the concatenation baseline outperform SegFormer.", + "bbox": [ + 76, + 209, + 356, + 255 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 4: (Conditional) Semantic Change Detection. Predicting $\\hat{m}^{(2)}$ based on $f^{(2)}$ yields the best results w.r.t. the main objective SCS.", + "bbox": [ + 359, + 224, + 890, + 255 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.4. Cross-modal Binary Change Detection", + "text_level": 1, + "bbox": [ + 76, + 281, + 410, + 297 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We also evaluate MapFormer on the task of Cross-modal BCD, i.e. change detection when only post-change imagery and pre-change map information are given (see Table 3). Here, the concatenation baseline omits the pre-change image features $f^{(1)}$ . The semantic segmentation baselines are identical to the ones for Conditional BCD in Table 2 as they do not utilize $\\hat{m}^{(1)}$ . Again, we can see that MapFormer performs best, although the margin to the concatenation baseline is rather small (0.1% and 0.6% IoU, resp.). However, comparing the results with those in Table 2, we observe that bi-temporal methods are greatly outperformed in this setting as well, and the performance is still relatively close to Conditional BCD, which relies on bi-temporal images. This highlights the value of semantic input for change detection and shows that bi-temporal images are not critical for change detection when pre-change maps are available.", + "bbox": [ + 75, + 305, + 470, + 547 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.5. Semantic Change Detection", + "text_level": 1, + "bbox": [ + 76, + 559, + 326, + 574 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "For semantic change detection, one can integrate additional semantic segmentation heads into our framework. We provide the results for Conditional SCD and Cross-modal SCD in Table 4. Here, we follow the notation of [26] and denote the binary change IoU with BC (instead of IoU in Tables 2,3). In the first three rows of Table 4, we reuse the semantic segmentation baselines of Table 2. The fourth and fifth rows correspond to MapFormer, with the semantic segmentation outputs being predicted from the uni-temporal image features (sem. seg. on $f^{(2)}$ ) and the merged features (sem. seg. on $f$ ), respectively. Apparently, the version with a segmentation head applied on $f^{(2)}$ performs better w.r.t. BC, SC, and SCS, whereas the joint version is superior w.r.t. mIoU. Our reasoning is that the imbalance between changed and unchanged areas in the data causes the model using $f$ to tend to repeat the given semantic information, which is not accessible through $f^{(2)}$ . This hurts the performance on changed pixels (SC), but leads to higher overall mIoU. In the last row of Table 4, we show the results for MapFormer solely based on uni-temporal images (Cross-modal), using $f^{(2)}$ for semantic segmentation. Sim", + "bbox": [ + 75, + 583, + 470, + 901 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "ilar to our observations for BCD, this model is competitive to its counterpart for Conditional SCD (25.5% vs. 26.0% and 33.5% vs. 34.7% SCS, resp.). This implies that $m^{(1)}$ has a stronger impact on the performance than $I^{(1)}$ .", + "bbox": [ + 496, + 282, + 890, + 343 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.6. Qualitative Results", + "text_level": 1, + "bbox": [ + 500, + 373, + 683, + 388 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "The first row of Figure 4 (a) depicts inputs and ground-truth targets for a sample of DynamicEarthNet. The second row shows the binary change predictions of several methods for this sample. We can see that SegFormer suffers from many false positive predictions, while the other state-of-the-art methods struggle to detect the changed areas. In contrast, MapFormer produces a convincing change mask where only small details are missing.", + "bbox": [ + 496, + 402, + 890, + 525 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In Figure 4 (b), we visualize the attention weights of MapFormer for this sample. The visualizations correspond to the argmax over the $K$ -dimension of the attention weights $a_{(\\cdot ,\\cdot ,k,d)}$ for six different channels $d$ . In other words, the colors in each visualization show which of the features $(h_k)_{k = 1\\dots K}$ receive most attention for the selected channels. Comparing them, we can see that the maps focus on different aspects of the semantic information $m_{1}$ . For example, the first attention map mostly resembles the original map $m^{(1)}$ , whereas the second and third visualizations resemble more coarse versions of $m_{1}$ . On the other hand, the fourth map focuses more on small and thin segments such as roads. The remaining two attention maps seem to aim at separating the features for specific semantic classes.", + "bbox": [ + 496, + 531, + 890, + 743 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "To provide further insight, we compare t-SNE [27] visualizations of the hidden features of MapFormer and FHD in Figure 4 (c). Each point in the visualization represents the hidden feature for one pixel in the sample depicted in subfigure (a). For MapFormer, the feature space is much less entangled, and the semantic classes of the pixels and the binary change ground truth can be separated from other pixels relatively well. In contrast, the FHD representations for different semantic and binary change classes are highly mixed, leading to prediction errors.", + "bbox": [ + 496, + 750, + 890, + 901 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "16843", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/965499b0b5853f4d37485dbc7f6d85670cdccce1f7a1cdb0afdd1570476e1e13.jpg", + "image_caption": [ + "(a) Binary change prediction for different methods." + ], + "image_footnote": [], + "bbox": [ + 122, + 93, + 844, + 362 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/f215da9a06252f105cb9e52c661bb414e15bfb7ae7fcbd70f204f2010b59bc09.jpg", + "image_caption": [ + "(b) Visualization of attentions weights. Colors encode which of the representations $(h_k)_{k = 1\\dots K}$ received most attention for six selected channels $d$ , exhibiting a focus on different aspects of the features for different $k$ and $d$ ." + ], + "image_footnote": [], + "bbox": [ + 125, + 383, + 841, + 479 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/9e7969a859e4c0f6a7d292f789443c3a71f8b5c83e03d4eda5b3fb343c5a6578.jpg", + "image_caption": [ + "(c.1) FHD [sem. classes]" + ], + "image_footnote": [], + "bbox": [ + 138, + 521, + 269, + 617 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/41cfe88567adb453994f51abce1fe291fd594f3cb352c35e15e0a7ea3cc07ac3.jpg", + "image_caption": [ + "(c.2) FHD [bin. change]" + ], + "image_footnote": [], + "bbox": [ + 326, + 521, + 455, + 617 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/e204a0bb457111d50ea4db0e365d630094409670f240db1abe0b506bd29a8dea.jpg", + "image_caption": [ + "(c.3) MapFormer [sem. classes] (c.4) MapFormer [bin. change]", + "(c) t-SNE [27] visualizations of hidden features of FHD and our model. In the plots (c.1) and (c.3), colors correspond to the semantic classes of $m1$ , whereas in (c.2) and (c.4), colors encode the binary change ground truth $b$ (change, no change)." + ], + "image_footnote": [], + "bbox": [ + 514, + 521, + 643, + 618 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/efff98210e2b4190a39c6e3f1f7963755cf9f4a1b9791b847df15afec3e40c5e.jpg", + "image_caption": [ + "Figure 4: Qualitative results and insights for a sample of DynamicEarthNet." + ], + "image_footnote": [], + "bbox": [ + 702, + 521, + 830, + 617 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 729, + 194, + 746 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this paper, we have introduced Conditional Change Detection, a new paradigm for change detection. We have shown that using available pre-change semantic information as input leads to significant improvements over existing methods for change detection. This holds even for a simple baseline that solely relies on feature concatenation. To further improve the performance, we have proposed MapFormer, a novel architecture outperforming its competitors in all considered settings. A limitation of our approach is", + "bbox": [ + 75, + 763, + 470, + 902 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "the requirement of semantic pre-change information. In the future, we plan to mitigate this dependency by leveraging pre-trained models to generate pre-change maps via transfer learning. Further, we see room for improvement w.r.t. the semantic segmentation pipeline of our approach if more sophisticated techniques are integrated for this purpose. We hope this work will lead to further research following the avenue of Conditional Change Detection. In particular, we believe that more diverse datasets, more sophisticated methods, and other settings, such as uni-temporal supervision as in [33], will greatly benefit this line of research.", + "bbox": [ + 496, + 732, + 890, + 898 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "16844", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Nicolas Audebert, Bertrand Le Saux, and Sébastien Lefèvre. Joint learning from earth observation and openstreetmap data to get faster better semantic maps. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 67-75, 2017. 2", + "[2] Wele Gedara Chaminda Bandara and Vishal M Patel. A transformer-based siamese network for change detection. arXiv preprint arXiv:2201.01293, 2022. 1, 2, 3, 5, 6", + "[3] Favyen Bastani and Samuel Madden. Beyond road extraction: A dataset for map update using aerial images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 11905-11914, 2021. 2", + "[4] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In European conference on computer vision, pages 213-229. Springer, 2020. 2", + "[5] Hao Chen, Zipeng Qi, and Zhenwei Shi. Remote sensing image change detection with transformers. IEEE Transactions on Geoscience and Remote Sensing, 60:1-14, 2021. 2", + "[6] Hao Chen and Zhenwei Shi. A spatial-temporal attention-based method and a new dataset for remote sensing image change detection. Remote Sensing, 12(10):1662, 2020. 2, 5", + "[7] Rodrigo Caye Daudt, Bertr Le Saux, and Alexandre Boulch. Fully convolutional siamese networks for change detection. In 2018 25th IEEE International Conference on Image Processing (ICIP), pages 4063-4067. IEEE, 2018. 2", + "[8] Rodrigo Caye Daudt, Bertrand Le Saux, Alexandre Boulch, and Yann Gousseau. Multitask learning for large-scale semantic change detection. Computer Vision and Image Understanding, 187:102783, 2019. 2, 5", + "[9] Sandra Díaz, Josef Settele, Eduardo S Brondízio, Hien T Ngo, John Agard, Almut Arneth, Patricia Balvanera, Kate A Brauman, Stuart HM Butchart, Kai MA Chan, et al. Pervasive human-driven decline of life on earth points to the need for transformative change. Science, 366(6471):eaax3100, 2019. 1", + "[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020. 2", + "[11] Sheng Fang, Kaiyu Li, and Zhe Li. Changer: Feature interaction is what you need for change detection. arXiv preprint arXiv:2209.08290, 2022. 2, 5, 6", + "[12] Sheng Fang, Kaiyu Li, Jinyuan Shao, and Zhe Li. Snunet-cd: A densely connected siamese network for change detection of vhr images. IEEE Geoscience and Remote Sensing Letters, 19:1-5, 2021. 2", + "[13] Shunping Ji, Shiqing Wei, and Meng Lu. Fully convolutional networks for multisource building extraction from an open aerial and satellite imagery data set. IEEE Transactions on Geoscience and Remote Sensing, 57(1):574-586, 2018. 2", + "[14] Huiwei Jiang, Min Peng, Yuanjun Zhong, Haofeng Xie, Zemin Hao, Jingming Lin, Xiaoli Ma, and Xiangyun Hu. A survey on deep learning-based change detection from" + ], + "bbox": [ + 78, + 114, + 468, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "high-resolution remote sensing images. Remote Sensing, 14(7):1552, 2022. 2", + "[15] Lazhar Khelifi and Max Mignotte. Deep learning for change detection in remote sensing images: Comprehensive review and meta-analysis. IEEE Access, 8:126385-126400, 2020. 2", + "[16] Weijia Li, Conghui He, Jiarui Fang, Juepeng Zheng, Haohuan Fu, and Le Yu. Semantic segmentation-based building footprint extraction using very high-resolution satellite images and multi-source gis data. Remote Sensing, 11(4):403, 2019. 2", + "[17] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF international conference on computer vision, pages 10012-10022, 2021. 5, 6", + "[18] Hyeoncheol Noh, Jingi Ju, Minseok Seo, Jongchan Park, and Dong-Geol Choi. Unsupervised change detection based on image reconstruction loss. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1352–1361, 2022. 2", + "[19] Gensheng Pei and Lulu Zhang. Feature hierarchical differentiation for remote sensing image change detection. IEEE Geoscience and Remote Sensing Letters, 2022. 2, 3, 4, 5, 6", + "[20] Minseok Seo, Hakjin Lee, Yongjin Jeon, and Junghoon Seo. Self-pair: Synthesizing changes from single source for object change detection in remote sensing imagery. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 6374-6383, 2023. 2", + "[21] Li Shen, Yao Lu, Hao Chen, Hao Wei, Donghai Xie, Jiabao Yue, Rui Chen, Shouye Lv, and Bitao Jiang. S2looking: A satellite side-looking dataset for building change detection. Remote Sensing, 13(24):5094, 2021. 2, 5", + "[22] Nian Shi, Keming Chen, and Guangyao Zhou. A divided spatial and temporal context network for remote sensing change detection. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 15:4897-4908, 2022. 2", + "[23] Wojciech Sirko, Sergii Kashubin, Marvin Ritter, Abigail Annkah, Yasser Salah Eddine Bouchareb, Yann Dauphin, Daniel Keysers, Maxim Neumann, Moustapha Cisse, and John Quinn. Continental-scale building detection from high resolution satellite imagery. arXiv preprint arXiv:2107.12283, 2021. 1", + "[24] D. M. Theobald, C. Kennedy, B. Chen, J. Oakleaf, S. Baruch-Mordo, and J. Kiesecker. Earth transformed: detailed mapping of global human modification from 1990 to 2017. Earth System Science Data, 12(3):1953-1972, 2020. 1", + "[25] Zhi Tian, Chunhua Shen, and Hao Chen. Conditional convolutions for instance segmentation. In European conference on computer vision, pages 282-298. Springer, 2020. 4", + "[26] Aysim Toker, Lukas Kondmann, Mark Weber, Marvin Eisenberger, Andrés Camero, Jingliang Hu, Ariadna Pregel Hoderlein, Caglar Şenaras, Timothy Davis, Daniel Cremers, et al. Dynamicearthnet: Daily multi-spectral satellite dataset for semantic change segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 21158-21167, 2022. 1, 2, 3, 5, 7" + ], + "bbox": [ + 503, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "16845", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[27] Laurens Van der Maaten and Geoffrey Hinton. Visualizing data using t-sne. Journal of machine learning research, 9(11), 2008. 7, 8", + "[28] Tete Xiao, Yingcheng Liu, Bolei Zhou, Yuning Jiang, and Jian Sun. Unified perceptual parsing for scene understanding. In Proceedings of the European conference on computer vision (ECCV), pages 418-434, 2018. 5, 6", + "[29] Enze Xie, Wenhai Wang, Zhiding Yu, Anima Anandkumar, Jose M Alvarez, and Ping Luo. Segformer: Simple and efficient design for semantic segmentation with transformers. Advances in Neural Information Processing Systems, 34:12077-12090, 2021. 2, 3, 4, 5, 6", + "[30] Lingfeng Yang, Xiang Li, Renjie Song, Borui Zhao, Jun-tian Tao, Shihao Zhou, Jiajun Liang, and Jian Yang. Dynamic mlp for fine-grained image classification by leveraging geographical and temporal information. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10945-10954, 2022. 4, 5, 6", + "[31] Chenxiao Zhang, Peng Yue, Deodato Tapete, Liangcun Jiang, Boyi Shangguan, Li Huang, and Guangchao Liu. A deeply supervised image fusion network for change detection in high resolution bi-temporal remote sensing images. ISPRS Journal of Photogrammetry and Remote Sensing, 166:183-200, 2020. 2, 5", + "[32] Sixiao Zheng, Jiachen Lu, Hengshuang Zhao, Xiatian Zhu, Zekun Luo, Yabiao Wang, Yanwei Fu, Jianfeng Feng, Tao Xiang, Philip HS Torr, et al. Rethinking semantic segmentation from a sequence-to-sequence perspective with transformers. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 6881-6890, 2021. 5, 6", + "[33] Zhuo Zheng, Ailong Ma, Liangpei Zhang, and Yanfei Zhong. Change is everywhere: Single-temporal supervised object change detection in remote sensing imagery. In Proceedings of the IEEE/CVF international conference on computer vision, pages 15193-15202, 2021. 2, 8", + "[34] Zongwei Zhou, Md Mahfuzur Rahman Siddiquee, Nima Tajbakhsh, and Jianming Liang. Unet++: A nested u-net architecture for medical image segmentation. In Deep learning in medical image analysis and multimodal learning for clinical decision support, pages 3-11. Springer, 2018. 2" + ], + "bbox": [ + 78, + 90, + 468, + 667 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "16846", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/8472e89b-fe96-412d-8c9c-414b2c42d2f3_model.json b/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/8472e89b-fe96-412d-8c9c-414b2c42d2f3_model.json new file mode 100644 index 0000000000000000000000000000000000000000..9fd7b07dfab546a12c702fb94dbf67735f076800 --- /dev/null +++ b/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/8472e89b-fe96-412d-8c9c-414b2c42d2f3_model.json @@ -0,0 +1,1672 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.109, + 0.131, + 0.865, + 0.154 + ], + "angle": 0, + "content": "MapFormer: Boosting Change Detection by Using Pre-change Information" + }, + { + "type": "text", + "bbox": [ + 0.263, + 0.181, + 0.709, + 0.216 + ], + "angle": 0, + "content": "Maximilian Bernhard, Niklas Strauß, Matthias Schubert LMU Munich, MCML" + }, + { + "type": "text", + "bbox": [ + 0.3, + 0.219, + 0.672, + 0.234 + ], + "angle": 0, + "content": "{bernhard,strauss, schubert}@dbs.ifi.lmu.de" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.269, + 0.314, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.302, + 0.474, + 0.71 + ], + "angle": 0, + "content": "Change detection in remote sensing imagery is essential for a variety of applications such as urban planning, disaster management, and climate research. However, existing methods for identifying semantically changed areas overlook the availability of semantic information in the form of existing maps describing features of the earth's surface. In this paper, we leverage this information for change detection in bi-temporal images. We show that the simple integration of the additional information via concatenation of latent representations suffices to significantly outperform state-of-the-art change detection methods. Motivated by this observation, we propose the new task of Conditional Change Detection, where pre-change semantic information is used as input next to bi-temporal images. To fully exploit the extra information, we propose MapFormer, a novel architecture based on a multi-modal feature fusion module that allows for feature processing conditioned on the available semantic information. We further employ a supervised, cross-modal contrastive loss to guide the learning of visual representations. Our approach outperforms existing change detection methods by an absolute \\(11.7\\%\\) and \\(18.4\\%\\) in terms of binary change IoU on DynamicEarthNet and HRSCD, respectively. Furthermore, we demonstrate the robustness of our approach to the quality of the pre-change semantic information and the absence pre-change imagery. The code is available at https://github.com/mxbh/mapformer." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.74, + 0.21, + 0.755 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Earth observation data has become increasingly available in recent years, providing valuable insights into various fields such as climate research, disaster management, and urban planning. In the course of this, enormous efforts have been made towards creating rich semantic maps of the earth. For instance, OpenStreetMap provides vast amounts of data containing manual annotations around the globe. In addition, deep learning techniques are nowadays used to produce semantic map data at a large scale, e.g., [23]" + }, + { + "type": "image", + "bbox": [ + 0.507, + 0.27, + 0.889, + 0.53 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.543, + 0.894, + 0.62 + ], + "angle": 0, + "content": "Figure 1: Advantage of our approach over existing change detection methods (represented by ChangeFormer [2] here) on a sample of DynamicEarthNet [26]. Employing semantic pre-change information allows to extract better features and improves change detection quality." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.655, + 0.893, + 0.852 + ], + "angle": 0, + "content": "generated building footprints for the entire African continent. As a result, we live in a world that has been extensively mapped. However, we live in a constantly changing world where the earth's surface is subject to various influences. These influences can be natural, e.g., earthquakes, extreme weather, floods, wildfires, and changes in vegetation, but also directly caused by humans, e.g., building construction, deforestation, and agriculture. In fact, the impact of civilization on our planet has never been higher than in recent years, with drastic consequences for ecosystems and wildlife [9, 24]. Therefore, monitoring changes in the earth's surface with up-to-date earth observation data is becoming increasingly important." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.894, + 0.903 + ], + "angle": 0, + "content": "In technical terms, this challenge is addressed by the task of change detection, where bi-temporal images are compared in order to segment pixels that have semanti-" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "16837" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.318 + ], + "angle": 0, + "content": "cally changed. Today, deep-learning-based methods for change detection achieve state-of-the-art performance [14, 15]. However, the research community so far mostly ignored the fact that existing semantic information like maps may be employed for change detection. To the best of our knowledge, semantic map information has been considered an additional input next to bi-temporal images for detecting change only for the specific task of updating road networks [3]. Although this approach is only possible if semantic information for the area of interest is available, we argue that maps are available for most parts of the world today. Alternatively, pre-trained neural networks can be used to generate a map containing the features of interest. Furthermore, when updating a map, a pre-change version of the map has to be available in the first place." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.319, + 0.473, + 0.65 + ], + "angle": 0, + "content": "In this paper, we tap into this direction in a general way and establish the novel task of Conditional Change Detection (see Figure 1). We demonstrate that the usage of semantic information in form of a pixelwise map has a strong impact on change detection by showing that a simple baseline (concatenating bi-temporal image features and map features) is already able to outperform state-of-the-art change detection methods, which do not use semantic pre-change information. Furthermore, we propose MapFormer, a novel architecture to fully exploit the additional information. At its core, we integrate a newly designed multi-modal feature fusion module based on the idea that the pre-change semantics should dynamically influence the processing of hidden features. Additionally, we apply a supervised contrastive loss on the learned image features, guiding the image encoder during training and further improving the performance. We also show that our approach can be applied without bi-temporal imagery, detecting change by only processing a pre-change map and current imagery. We call this task Cross-modal Change Detection. We conduct experiments on the publicly available and challenging datasets DynamicEarthNet [26] and HRSCD [8]." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.651, + 0.424, + 0.665 + ], + "angle": 0, + "content": "To sum up, our main contributions are as follows:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.672, + 0.468, + 0.731 + ], + "angle": 0, + "content": "- We investigate the novel tasks of Conditional Change Detection and Cross-modal Change Detection and introduce simple baselines that outperform state-of-the-art change detection methods." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.731, + 0.468, + 0.789 + ], + "angle": 0, + "content": "- We propose MapFormer, a novel architecture consisting of a multi-modal feature fusion module and a supervised contrastive loss, allowing us to effectively merge image features and semantic information." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.789, + 0.468, + 0.834 + ], + "angle": 0, + "content": "- We conduct detailed experiments and ablations demonstrating our approach's consistent performance gains, robustness, and practicability." + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.672, + 0.468, + 0.834 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.846, + 0.219, + 0.86 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.871, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Change detection in remote sensing images has attracted much attention over the last years, resulting in numerous" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.393 + ], + "angle": 0, + "content": "publications in this field [14, 15, 19, 2, 11, 12, 33, 18, 20]. Most state-of-the-art methods employ deep learning and introduce various sophisticated ways of merging bi-temporal image features. For instance, [7] proposes a series of fully convolutional architectures for change detection that rely on different fusion mechanisms for the bi-temporal image features. Furthermore, [12] uses NestedUNet [34] in combination with channel attention. With the introduction of transformer architectures into computer vision [10, 4, 29], recent architectures for change detection also utilize attention blocks. BiT [5] was the first of these methods, combining a CNN backbone with cross-attention layers in the decoder head. Subsequently, works like CDViT [22], ChangeFormer [2], FHD [19], and Changer [11] use the attention mechanism in various forms, pushing the state-of-the-art in bi-temporal change detection even further. Our general architecture is inspired by ChangeFormer and FHD, which adopt the MiT backbone and the MLP head from SegFormer [29] and add specialized mechanisms to fuse the bi-temporal image features." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.394, + 0.892, + 0.786 + ], + "angle": 0, + "content": "LEVIR-CD [6], DSIFN-CD [31], WHU [13], and S2Looking [21] are common benchmark datasets for bi-temporal change detection, where networks are provided with co-registered, bi-temporal images as input and have to predict a pixelwise, binary change mask. Recently, a new dataset for change detection has been published with DynamicEarthNet [26], which surpasses previous datasets in terms of volume and diversity. In addition, models have to predict semantic segmentation masks containing the land cover classes next to the binary change masks for this dataset. However, none of these methods or datasets consider inputs other than bi- or multi-temporal images. Thus, previous approaches ignore the fact that pre-change semantic information for the area of interest is often available. For semantic segmentation on the other hand, it has been shown that semantic maps extracted from geographic information systems (GIS) can be effectively used to improve segmentation quality [1, 16]. In a change detection setting, only for the specific task of road network extraction [3] challenged the community to come up with solutions for updating road networks when pre-change road networks are given. Consequently, their approach considers graph data as input and output. In contrast, we consider the pixelwise change detection task when pre-change semantic information in the form of a pixelwise map is available and show that this paradigm opens up exciting new possibilities." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.8, + 0.776, + 0.817 + ], + "angle": 0, + "content": "3. Conditional Change Detection" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.892, + 0.901 + ], + "angle": 0, + "content": "We consider two points in time \\( t_1 \\) (pre-change) and \\( t_2 \\) (post-change). Correspondingly, we have two image versions \\( I^{(1)} \\) and \\( I^{(2)} \\) for the same geographic location at \\( t_1 \\) and \\( t_2 \\), respectively. The ground-truth binary mask \\( b \\) indicates which pixels in the images have changed semanti" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.956 + ], + "angle": 0, + "content": "16838" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.08, + 0.089, + 0.472, + 0.216 + ], + "angle": 0, + "content": "
TaskInput I(1)I(2)m(1)Output b m(2)
Bi-temp. Bin. Change Det. (BCD)✓✓✓
Bi-temp. Sem. Change Det. (SCD)✓✓✓
[ new]Conditional BCD✓✓✓
[ new]Conditional SCD✓✓✓
[ new]Cross-modal BCD✓✓
[ new]Cross-modal SCD✓✓
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.226, + 0.47, + 0.255 + ], + "angle": 0, + "content": "Table 1: Inputs and outputs for different change detection tasks." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.282, + 0.47, + 0.403 + ], + "angle": 0, + "content": "cally between \\( t_1 \\) and \\( t_2 \\). Furthermore, we consider semantic maps \\( m^{(1)} \\) and \\( m^{(2)} \\) containing the semantic class \\( c \\in \\mathcal{C} \\) for each pixel in \\( I^{(1)} \\) and \\( I^{(2)} \\), respectively. Thus, \\( b \\) can be obtained from \\( m^{(1)} \\) and \\( m^{(2)} \\) via a pixelwise inequality operation. As we propose new tasks in this paper (Conditional Change Detection and Cross-modal Change Detection), we provide a differentiated description of the existing and novel tasks here. An overview can be seen in Table 1." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.404, + 0.471, + 0.646 + ], + "angle": 0, + "content": "Existing Tasks In general, change detection tasks differ in two aspects: input and output. We can distinguish w.r.t. the output between binary and semantic change detection (BCD and SCD) for every combination of inputs. In BCD, the goal is to predict the binary change mask \\(\\hat{b}\\), indicating which pixels have changed semantically. SCD was recently proposed in [26] and constitutes an extension of BCD. Here, not only the binary change mask \\(\\hat{b}\\) is predicted, but also the semantic segmentation \\(\\hat{m}^{(2)}\\) of the post-change image \\(I^{(2)}\\). This allows us to tell which regions have changed and how they have changed. The corresponding evaluation metric \\(SCS\\) proposed in [26] combines the binary change IoU \\(BC\\) and the semantic change metric \\(SC\\) as their arithmetic mean. The semantic change metric \\(SC\\) is the standard mIoU from semantic segmentation, except that it is computed only on the pixels that have changed, i.e." + }, + { + "type": "equation", + "bbox": [ + 0.082, + 0.655, + 0.465, + 0.694 + ], + "angle": 0, + "content": "\\[\nS C = \\frac {1}{| \\mathcal {C} |} \\sum_ {c \\in \\mathcal {C}} \\frac {| \\{b = 1 \\} \\cap \\{m ^ {(2)} = c \\} \\cap \\{\\hat {m} ^ {(2)} = c \\} |}{| \\{b = 1 \\} \\cap (\\{m ^ {(2)} = c \\} \\cup \\{\\hat {m} ^ {(2)} = c \\}) |},\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.084, + 0.697, + 0.47, + 0.726 + ], + "angle": 0, + "content": "\\[\nB C = I o U (b, \\hat {b}) \\quad \\text {a n d} \\quad S C S = \\frac {B C + S C}{2} \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.47, + 0.78 + ], + "angle": 0, + "content": "Regarding the input, the existing settings consider bi-temporal images \\( I^{(1)} \\) and \\( I^{(2)} \\). Thus, we will refer to the existing tasks as bi-temporal BCD and bi-temporal SCD." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.781, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Conditional Change Detection While the aforementioned change detection tasks assume bi-temporal images as input, semantic information in the form of a segmentation map \\( m^{(1)} \\) at \\( t_1 \\) may be employed additionally. That is, given pre- and post-change images together with pre-change semantic information \\( m^{(1)} \\), the goal is to predict the binary change mask \\( \\hat{b} \\) for Conditional BCD (as well as the semantic segmentation map \\( \\hat{m}^{(2)} \\) for Conditional SCD)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.894, + 0.244 + ], + "angle": 0, + "content": "Cross-modal Change Detection When pre-change semantic maps are available, change detection can also be conducted without bi-temporal, but solely uni-temporal imagery. In this case, only comparing the semantic information \\( m^{(1)} \\) and the current imagery \\( I^{(2)} \\) can suffice to detect semantic changes. In other words, this setting corresponds to Conditional Change Detection with uni-temporal images. We call this task Cross-modal Change Detection as the change has to be detected across different modalities (semantic pre-change map and post-change image)." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.258, + 0.63, + 0.275 + ], + "angle": 0, + "content": "4. MapFormer" + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.283, + 0.697, + 0.298 + ], + "angle": 0, + "content": "4.1. Overall Architecture" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.307, + 0.893, + 0.579 + ], + "angle": 0, + "content": "To handle these new tasks, we propose a framework, which is inspired by [19, 2] (see Figure 2). We feed the images \\( I^{(1)} \\) and \\( I^{(2)} \\) through the same backbone to obtain multi-scale feature maps \\( f^{(1)} \\) and \\( f^{(2)} \\). For each scale, we have a separate fusion module (see Section 4.2) that handles the features from \\( f^{(1)} \\) and \\( f^{(2)} \\) at the corresponding scale. In addition to the image features, in our setting, we also feed semantic information in the form of an encoded map \\( g^{(1)} \\) into the fusion modules. These map features are obtained from \\( m^{(1)} \\) via a shallow encoder (see Section 4.4). The outputs of the fusion modules are then multi-scale features \\( f \\), containing information of both points in time \\( t_1 \\) and \\( t_2 \\). Thus, we can use them in a prediction head to output the binary change map \\( \\hat{b} \\). In terms of architecture, this prediction head is a standard semantic segmentation head [29]. Furthermore, we apply a contrastive loss on the image features \\( f^{(1)} \\) and \\( f^{(2)} \\), which helps the model to learn semantically more meaningful representations (see Section 4.3)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.58, + 0.894, + 0.806 + ], + "angle": 0, + "content": "For many applications, it may be interesting to determine into which semantic class a pixel has changed. In this case, we also need to derive a semantic segmentation map \\(\\hat{m}^{(2)}\\) for \\(I^{(2)}\\). We can accomplish this either by feeding the unitemporal features \\(f^{(2)}\\) into a separate head for semantic segmentation or by predicting both \\(\\hat{b}\\) and \\(\\hat{m}^{(2)}\\) based on the merged features \\(f\\). We analyze both variants in Section 5.5. Training a semantic segmentation head on uni-temporal image features also allows applying the trained model without pre-change information as we can use the predicted semantic segmentation \\(\\hat{m}^{(1)}\\) instead of \\(m^{(1)}\\). Results for this setting are provided in Section 5.3. Furthermore, for Cross-modal Change Detection, the design of our fusion module (described next) enables us to omit the image features \\(f^{(1)}\\) from \\(I^{(1)}\\). We evaluate this setting in Section 5.4." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.817, + 0.755, + 0.832 + ], + "angle": 0, + "content": "4.2. Multi-modal Feature Fusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.894, + 0.902 + ], + "angle": 0, + "content": "The main challenge in bi-temporal change detection is to design an effective method for fusing the bi-temporal image features. In the case of Conditional (and Cross-modal) Change Detection, we additionally have to bring together" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "16839" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.139, + 0.089, + 0.855, + 0.301 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.314, + 0.895, + 0.349 + ], + "angle": 0, + "content": "Figure 2: The proposed MapFormer framework consists of two main components: a novel fusion module, which combines inputs from different points in time and modalities, and a contrastive loss module, which is only used during training." + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.374, + 0.456, + 0.49 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.501, + 0.471, + 0.534 + ], + "angle": 0, + "content": "Figure 3: Our multi-modal feature fusion module for fusing bi-temporal image features and semantic input features." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.565, + 0.47, + 0.657 + ], + "angle": 0, + "content": "different modalities, i.e., the image features and the available semantic information. To this end, we propose a novel multi-modal feature fusion module. Subsequently, we follow [19, 29] and assume that the spatial context is encoded within the backbone, so we only consider pointwise operations, treating each spatial location separately." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.66, + 0.471, + 0.903 + ], + "angle": 0, + "content": "A standard way of merging multi-modal features is a simple concatenation along the channel dimension. However, we argue that the semantic information in our setting can be used more effectively if we use it to modulate the features dynamically. Thus, the given information should influence the processing of image features and thereby improve perception. Such data-dependent feature processing can be achieved by dynamically predicting the weights of one or more layers from the features themselves [30, 25]. While such techniques are powerful, they come at a significant computational cost. In fact, applying a method like DynamicMLP [30] to a segmentation task like ours by predicting dynamic weights for each pixel separately is intractable without drastically reducing the number of channels (or the spatial resolution). Therefore, we resort to a restricted attention-style approach. More precisely, to keep" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.371, + 0.892, + 0.416 + ], + "angle": 0, + "content": "the computational cost tractable, we restrict the attention to a set of \\( K \\) values for each output dimension, thereby greatly reducing the complexity compared to unrestricted attention." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.417, + 0.893, + 0.735 + ], + "angle": 0, + "content": "A visualization of our proposed multi-modal feature fusion module can be seen in Figure 3. First, we concatenate the bi-temporal features \\( f_{(i,j)}^{(1)} \\) and \\( f_{(i,j)}^{(2)} \\) and the map feature \\( g_{(i,j)}^{(1)} \\) for each spatial location \\( (i,j) \\). This concatenated feature is fed through \\( K \\) separate MLPs (implemented with grouped, pointwise convolutions) to obtain \\( K \\) joint representations \\( (h_{k(i,j)})_{k=1\\dots K} \\) with \\( D_f \\) channels. Here, \\( D_f \\) refers to the dimensionality of \\( f_{(i,j)}^{(t)}, t = 1,2 \\), and \\( K \\) is a hyperparameter for tuning the semantic variety. These \\( K \\) joint representations \\( (h_{k(i,j)})_{k=1\\dots K} \\) can be interpreted as views, encoding different aspects of the same spatial location. To associate the map information \\( g_{(i,j)}^{(1)} \\) with these views, we employ a channelwise attention mechanism. In particular, we compute attention weights by feeding the map features \\( g_{(i,j)}^{(1)} \\) into an additional MLP. The result of shape \\( K\\times D_f \\) is softmaxed over the \\( K \\)-dimension providing a matrix of attention scores with entries \\( a_{(i,j,k,d)} \\) for location \\( (i,j) \\). Thus, each channel of the module output \\( f_{(i,j)} \\) separately attends to the \\( K \\) joint representations \\( (h_{k(i,j)})_{k=1\\dots K} \\). In mathematical terms, we compute" + }, + { + "type": "equation", + "bbox": [ + 0.547, + 0.742, + 0.892, + 0.788 + ], + "angle": 0, + "content": "\\[\nf _ {(i, j)} = \\left(\\sum_ {k = 1 \\dots K} a _ {(i, j, k, d)} h _ {k (i, j, d)}\\right) _ {d = 1 \\dots D _ {f}} \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.794, + 0.892, + 0.84 + ], + "angle": 0, + "content": "The merged features \\( f_{(i,j)} \\) are then collected for the different scales of the backbone feature maps and passed to the prediction head." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.848, + 0.667, + 0.862 + ], + "angle": 0, + "content": "4.3. Contrastive Loss" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.87, + 0.892, + 0.902 + ], + "angle": 0, + "content": "For unchanged areas, we want \\( f^{(1)}, f^{(2)} \\), and \\( g^{(1)} \\) to encode the same semantic concepts. For changed areas how-" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "16840" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.09, + 0.473, + 0.198 + ], + "angle": 0, + "content": "ever, the encoded information in \\( f^{(1)} \\) and \\( g^{(1)} \\) should be similar, while \\( f^{(2)} \\) should be dissimilar from the two. Based on this observation, we design a supervised contrastive loss that forces the network to learn better image features. More precisely, we apply a learnable projection \\( \\pi \\) to map \\( f^{(1)} \\) and \\( f^{(2)} \\) into the feature space of \\( g^{(1)} \\). Then, we compute our contrastive loss as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.078, + 0.2, + 0.473, + 0.276 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {L} _ {(i, j)} ^ {(c o n t r)} = - \\operatorname {s i m} \\left(g _ {(i, j)} ^ {(1)}, \\pi \\left(f _ {(i, j)} ^ {(1)}\\right)\\right) \\tag {3} \\\\ + \\left\\{ \\begin{array}{l l} - \\operatorname {s i m} \\left(g _ {(i, j)} ^ {(1)}, \\pi \\big (f _ {(i, j)} ^ {(2)} \\big)\\right), & b _ {(i, j)} = 0 \\\\ \\max \\left(\\operatorname {s i m} \\left(g _ {(i, j)} ^ {(1)}, \\pi \\big (f _ {(i, j)} ^ {(2)} \\big)\\right), 0\\right), & b _ {(i, j)} = 1. \\end{array} \\right. \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.28, + 0.471, + 0.371 + ], + "angle": 0, + "content": "Here, \\( \\operatorname{sim}(\\cdot, \\cdot) \\) denotes the cosine similarity, and the loss is ultimately aggregated over all pixel locations \\( (i,j) \\). Interestingly, we found it beneficial not to use a projection for \\( g^{(1)} \\) and also not to backpropagate gradients coming from the contrastive loss through \\( g^{(1)} \\). Details can be found in Section 5.3." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.378, + 0.269, + 0.393 + ], + "angle": 0, + "content": "4.4. Architecture Details" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.401, + 0.473, + 0.751 + ], + "angle": 0, + "content": "Like [19], we use the MixVisionTransformer from [29] as image encoder backbone. Due to the spatial attention in the encoder, the features \\( f_{(i,j)}^{(t)} \\) are already contextualized, and a pointwise prediction head after a pointwise fusion module suffices to produce high-quality predictions. We leave SegFormer's prediction head unchanged and solely plug in our proposed feature fusion module between the backbone and the head. Thus, our module can be easily combined with other architectures. Inside our feature fusion module, the merged features \\( (h_k)_{k=1\\dots K} \\) are produced by \\( K \\) two-layer MLPs, while the attention weights \\( a \\) are predicted from \\( g^{(1)} \\) via a linear layer. To encode the semantic information \\( m^{(1)} \\) into \\( g^{(1)} \\), we use a three-layer CNN with a pointwise convolution followed by two convolutions with a kernel size of five and a dilation of two to increase the receptive field. When fusing the encoded map \\( g^{(1)} \\), we use bilinear interpolation to comply with the different spatial resolutions of the different scales of the image feature maps. The projection head \\( \\pi \\) for the contrastive loss is a pointwise MLP head in the style of SegFormer's prediction head. The overall training loss is the sum of our contrastive loss and the cross-entropy loss for the binary change map (as well as the semantic segmentation in SCD)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.763, + 0.21, + 0.78 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.787, + 0.18, + 0.802 + ], + "angle": 0, + "content": "5.1. Datasets" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Since Conditional Change Detection requires semantic segmentation maps, which are not included in commonly used benchmark datasets such as LEVIR-CD [6], DSIFN-CD [31], and S2Looking [21], we conduct our experiments on DynamicEarthNet [26] and HRSCD [8]. DynamicEarthNet is a recent dataset consisting of daily images of 75 areas" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.273 + ], + "angle": 0, + "content": "of interest (AOIs) over a span of two years. Ground-truth annotations containing the seven land use classes \"impervious surface\", \"agriculture\", \"forest & other vegetation\", \"wetlands\", \"soil\", \"water\", and \"snow & ice\" are only available for the first day of each month and 55 AOIs. As our setting assumes semantic information as input, we only use the images with available annotations and selected 35, 10, and 10 AOIs for training, validation, and testing, respectively. Following [26], we omit the class \"snow & ice\" from the evaluation because it only occurs in two AOIs. Targets for binary change detection were created by applying a pixelwise inequality on pairs of ground-truth semantic maps." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.274, + 0.892, + 0.426 + ], + "angle": 0, + "content": "The High-Resolution Semantic Change Detection (HRSCD) dataset was proposed in [8]. It contains 291 pairs of images, where the first was acquired in 2005/2006 and the second in 2012. Semantic ground-truth segmentation maps and binary change segmentation maps are available for all samples. The semantic classes are \"artificial surface\", \"agricultural area\", \"forest\", \"wetland\", and \"water\". We selected 191, 50, and 50 pairs for training, validation, and testing, respectively. Further details on both datasets can be found in the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.439, + 0.608, + 0.453 + ], + "angle": 0, + "content": "5.2. Baselines" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.463, + 0.892, + 0.901 + ], + "angle": 0, + "content": "As baselines derived from semantic segmentation models, we employ SegFormer [29], Swin + UPerNet [17, 28], and SETR-PUP [32] for change detection by taking the pixelwise inequality of the predicted semantic segmentations \\(\\hat{m}^{(1)}\\) and \\(\\hat{m}^{(2)}\\) as binary change prediction. The concatenation baseline for bi-temporal BCD resembles the SegFormer architecture, but concatenates the image features \\(f^{(1)}\\) and \\(f^{(2)}\\) before passing them to a head that directly predicts the binary change map. These baselines can be easily reused for Conditional BCD. For the semantic segmentation baselines, we apply the pixelwise inequality to \\(m^{(1)}\\) and \\(\\hat{m}^{(2)}\\) instead of \\(\\hat{m}^{(1)}\\) and \\(\\hat{m}^{(2)}\\). For the concatenation baseline, we concatenate map features \\(g^{(1)}\\) extracted by a map encoder as described in Section 4.4 to the image features \\(f^{(1)}\\) and \\(f^{(2)}\\). As state-of-the-art methods for bi-temporal BCD, we select FHD [19], ChangerEx [11], and ChangeFormer [2] as they are recent and have been shown to perform best on the common benchmarks. We also extend these methods for Conditional BCD by concatenating map features to merged bi-temporal image features. Further, we consider another baseline for Conditional BCD, which has a separate concatenation-based BCD head for every semantic class such that the final change prediction can be taken from the head corresponding to the pre-change semantic class for every pixel. To have a strong competitor for our feature fusion module, we also use a pixel-wise Dynamic MLP-C [30] for fusing semantic input with image features. For training details as well as a comparison of model sizes, we refer to the supplementary material." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "16841" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.08, + 0.089, + 0.47, + 0.555 + ], + "angle": 0, + "content": "
MethodDynENetHRSCD
F1IoUF1IoU
Bi-temporal BCD:
SegFormer [29]20.311.317.89.7
Swin + UPerNet [17, 28]20.111.117.69.7
SETR-PUP [32]19.410.814.88.0
Concatenation20.711.641.225.9
FHD [19]17.29.445.229.2
ChangerEx [11]21.111.837.022.7
ChangeFormer [2]20.711.545.729.6
MapFormerK=10 (w/o m(1))28.616.743.928.2
Conditional BCD:
SegFormer [29]21.211.95.62.8
Swin + UPerNet [17, 28]21.812.25.62.8
SETR-PUP [32]20.811.65.42.8
Concatenation33.520.162.145.1
FHD [19] + Concat.33.219.961.244.1
ChangerEx [11] + Concat.30.918.358.141.0
ChangeFormer [2] + Concat.31.418.661.544.4
Classwise CD-Heads37.022.762.345.3
DynamicMLP [30]34.520.862.745.7
MapFormerK=534.821.164.948.0
MapFormerK=1038.023.564.547.7
MapFormerK=1536.422.264.547.6
Ablations (MapFormerK=10):
w/o constrastive34.520.963.846.8
w/o stop-gradient36.722.562.545.4
w/ map proj.35.821.860.745.9
high-level info29.817.664.447.5
low-res. info30.417.960.343.2
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.565, + 0.47, + 0.613 + ], + "angle": 0, + "content": "Table 2: (Conditional) Binary Change Detection as well as ablations. Our method performs best and is still highly competitive without ground-truth semantic input." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.646, + 0.308, + 0.663 + ], + "angle": 0, + "content": "5.3. Binary Change Detection" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.674, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Overall Performance In BCD, there is only a single objective (binary change IoU); thus, our approach can be best compared to other methods. In Table 2, we present BCD results for baselines, state-of-the-art methods, and our method. It is evident that Conditional BCD greatly outperforms all existing bi-temporal methods - even with the simple concatenation baseline (11.8% vs. 20.1% and 29.6% vs. 45.1% IoU, resp.). MapFormer further pushes the performance on both datasets to 23.5% and 48.0% IoU, respectively. Particularly, our method also outperforms DynamicMLP [30], a state-of-the-art method for multi-modal feature fusion. This holds for all tested values of our only hyperparameter \\( K \\) and even without our contrastive loss (see Ablations). Remarkably, when MapFormer is applied without the true map \\( m^{(1)} \\), but only predicted segmentation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.09, + 0.895, + 0.26 + ], + "angle": 0, + "content": "maps \\(\\hat{m}^{(1)}\\) (\\(w / o m^{(1)}\\)), the performance is still highly competitive, even achieving by far the best performance among the bi-temporal methods on DynamicEarthNet with an IoU of \\(16.7\\%\\). Furthermore, it is noteworthy that the semantic segmentation baselines SegFormer, Swin + UPerNet and SETR perform poorly in Conditional BCD, especially on HRSCD. We attribute this to the fact that every misclassified pixel leads to a false positive change prediction in this setup, causing a very low precision. In bi-temporal BCD, identical classification errors in \\(\\hat{m}^{(1)}\\) and \\(\\hat{m}^{(2)}\\) may still lead to true negative change predictions." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.277, + 0.895, + 0.506 + ], + "angle": 0, + "content": "Ablations In the lower part of Table 2, we present several ablation experiments to analyze MapFormer's contributing factors and robustness. First, we study the effect of our design choices in the contrastive loss module. When the contrastive loss is completely omitted (w/o contrastive), performance drops on both datasets by \\(2.6\\%\\) and \\(0.9\\%\\) IoU, respectively. Furthermore, we compare MapFormer with modifications where we omitted the stop-gradient operation on the map features \\(g^{(1)}\\) (w/o stop-gradient) and a version where we included a linear projection layer to map \\(g^{(1)}\\) to the joint embedding space with \\(\\pi \\left(f^{(t)}\\right)\\) (w/ map proj.). Both variants do not reach the performance of our proposed method. Thus, we conclude that gradients coming from the contrastive loss flowing through the map features \\(g^{(1)}\\) have a detrimental effect on their representation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.524, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Finally, we investigate the effect of the quality of the semantic information \\( m^{(1)} \\). To this end, we merge some classes in the pre-change maps to simulate that only high-level semantic information is available (high-level info). For DynamicEarthNet, we merge the classes \"agriculture\", \"forest & other vegetation\" and \"soil\" as well as \"wetlands\", \"water\" and \"snow & ice\" into two high-level classes, respectively. For HRSCD, we solely distinguish between \"artificial\" and \"rest\". Apparently, this high-level information still suffices to generate better change predictions than the bi-temporal change detection methods. However, we observe a significant performance drop on DynamicEarthNet (5.9% IoU), while the performance only degrades marginally on HRSCD (0.2% IoU). Furthermore, we simulate low-resolution semantic information by downsampling with a factor of 32 (low-res. info). Here, we can see that the performance of our method degrades with the low-resolution input (by 5.6% and 4.8% IoU, resp.). Nevertheless, it is still clearly superior to the bi-temporal change detection methods. In conclusion, our results show that the semantic input quality correlates to the Conditional Change Detection performance. However, low-quality input still suffices to achieve significantly better results than methods not relying on this kind of information. Further ablations can be found in the supplementary material." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "16842" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.079, + 0.089, + 0.353, + 0.201 + ], + "angle": 0, + "content": "
MethodDynENetHRSCD
F1IoUF1IoU
SegFormer21.211.95.62.8
Swin+UPerNet21.812.25.62.8
SETR-PUP20.811.65.42.8
Concatenation31.818.961.544.4
MapFormer32.019.062.145.0
" + }, + { + "type": "table", + "bbox": [ + 0.365, + 0.089, + 0.892, + 0.214 + ], + "angle": 0, + "content": "
MethodDynamicEarthNetHRSCD
BCSCSCSmIoUBCSCSCSmIoU
SegFormer11.331.521.439.79.720.315.052.7
Swin + UperNet11.128.019.641.49.720.915.353.1
SETR-PUP10.826.318.538.58.521.714.950.5
MapFormer (sem. seg. on f(2))23.029.026.039.948.021.534.752.9
MapFormer (sem. seg. on f)23.113.118.161.548.212.530.472.3
MapFormer (Cross-modal)20.430.725.540.345.621.733.549.9
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.21, + 0.357, + 0.256 + ], + "angle": 0, + "content": "Table 3: Cross-modal Binary Change Detection. MapFormer and the concatenation baseline outperform SegFormer." + }, + { + "type": "table_caption", + "bbox": [ + 0.36, + 0.225, + 0.892, + 0.256 + ], + "angle": 0, + "content": "Table 4: (Conditional) Semantic Change Detection. Predicting \\(\\hat{m}^{(2)}\\) based on \\(f^{(2)}\\) yields the best results w.r.t. the main objective SCS." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.282, + 0.411, + 0.299 + ], + "angle": 0, + "content": "5.4. Cross-modal Binary Change Detection" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.306, + 0.471, + 0.549 + ], + "angle": 0, + "content": "We also evaluate MapFormer on the task of Cross-modal BCD, i.e. change detection when only post-change imagery and pre-change map information are given (see Table 3). Here, the concatenation baseline omits the pre-change image features \\( f^{(1)} \\). The semantic segmentation baselines are identical to the ones for Conditional BCD in Table 2 as they do not utilize \\( \\hat{m}^{(1)} \\). Again, we can see that MapFormer performs best, although the margin to the concatenation baseline is rather small (0.1% and 0.6% IoU, resp.). However, comparing the results with those in Table 2, we observe that bi-temporal methods are greatly outperformed in this setting as well, and the performance is still relatively close to Conditional BCD, which relies on bi-temporal images. This highlights the value of semantic input for change detection and shows that bi-temporal images are not critical for change detection when pre-change maps are available." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.56, + 0.327, + 0.575 + ], + "angle": 0, + "content": "5.5. Semantic Change Detection" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.584, + 0.471, + 0.902 + ], + "angle": 0, + "content": "For semantic change detection, one can integrate additional semantic segmentation heads into our framework. We provide the results for Conditional SCD and Cross-modal SCD in Table 4. Here, we follow the notation of [26] and denote the binary change IoU with BC (instead of IoU in Tables 2,3). In the first three rows of Table 4, we reuse the semantic segmentation baselines of Table 2. The fourth and fifth rows correspond to MapFormer, with the semantic segmentation outputs being predicted from the uni-temporal image features (sem. seg. on \\( f^{(2)} \\)) and the merged features (sem. seg. on \\( f \\)), respectively. Apparently, the version with a segmentation head applied on \\( f^{(2)} \\) performs better w.r.t. BC, SC, and SCS, whereas the joint version is superior w.r.t. mIoU. Our reasoning is that the imbalance between changed and unchanged areas in the data causes the model using \\( f \\) to tend to repeat the given semantic information, which is not accessible through \\( f^{(2)} \\). This hurts the performance on changed pixels (SC), but leads to higher overall mIoU. In the last row of Table 4, we show the results for MapFormer solely based on uni-temporal images (Cross-modal), using \\( f^{(2)} \\) for semantic segmentation. Sim" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.283, + 0.892, + 0.344 + ], + "angle": 0, + "content": "ilar to our observations for BCD, this model is competitive to its counterpart for Conditional SCD (25.5% vs. 26.0% and 33.5% vs. 34.7% SCS, resp.). This implies that \\( m^{(1)} \\) has a stronger impact on the performance than \\( I^{(1)} \\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.374, + 0.684, + 0.39 + ], + "angle": 0, + "content": "5.6. Qualitative Results" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.404, + 0.892, + 0.526 + ], + "angle": 0, + "content": "The first row of Figure 4 (a) depicts inputs and ground-truth targets for a sample of DynamicEarthNet. The second row shows the binary change predictions of several methods for this sample. We can see that SegFormer suffers from many false positive predictions, while the other state-of-the-art methods struggle to detect the changed areas. In contrast, MapFormer produces a convincing change mask where only small details are missing." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.532, + 0.892, + 0.744 + ], + "angle": 0, + "content": "In Figure 4 (b), we visualize the attention weights of MapFormer for this sample. The visualizations correspond to the argmax over the \\(K\\)-dimension of the attention weights \\(a_{(\\cdot ,\\cdot ,k,d)}\\) for six different channels \\(d\\). In other words, the colors in each visualization show which of the features \\((h_k)_{k = 1\\dots K}\\) receive most attention for the selected channels. Comparing them, we can see that the maps focus on different aspects of the semantic information \\(m_{1}\\). For example, the first attention map mostly resembles the original map \\(m^{(1)}\\), whereas the second and third visualizations resemble more coarse versions of \\(m_{1}\\). On the other hand, the fourth map focuses more on small and thin segments such as roads. The remaining two attention maps seem to aim at separating the features for specific semantic classes." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.892, + 0.902 + ], + "angle": 0, + "content": "To provide further insight, we compare t-SNE [27] visualizations of the hidden features of MapFormer and FHD in Figure 4 (c). Each point in the visualization represents the hidden feature for one pixel in the sample depicted in subfigure (a). For MapFormer, the feature space is much less entangled, and the semantic classes of the pixels and the binary change ground truth can be separated from other pixels relatively well. In contrast, the FHD representations for different semantic and binary change classes are highly mixed, leading to prediction errors." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16843" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.123, + 0.094, + 0.845, + 0.363 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.334, + 0.367, + 0.637, + 0.381 + ], + "angle": 0, + "content": "(a) Binary change prediction for different methods." + }, + { + "type": "image", + "bbox": [ + 0.126, + 0.384, + 0.842, + 0.48 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.109, + 0.488, + 0.86, + 0.517 + ], + "angle": 0, + "content": "(b) Visualization of attentions weights. Colors encode which of the representations \\((h_k)_{k = 1\\dots K}\\) received most attention for six selected channels \\(d\\), exhibiting a focus on different aspects of the features for different \\(k\\) and \\(d\\)." + }, + { + "type": "image", + "bbox": [ + 0.139, + 0.522, + 0.27, + 0.618 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.129, + 0.63, + 0.278, + 0.643 + ], + "angle": 0, + "content": "(c.1) FHD [sem. classes]" + }, + { + "type": "image", + "bbox": [ + 0.328, + 0.522, + 0.457, + 0.618 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.319, + 0.63, + 0.464, + 0.643 + ], + "angle": 0, + "content": "(c.2) FHD [bin. change]" + }, + { + "type": "image", + "bbox": [ + 0.516, + 0.522, + 0.644, + 0.619 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.485, + 0.63, + 0.86, + 0.644 + ], + "angle": 0, + "content": "(c.3) MapFormer [sem. classes] (c.4) MapFormer [bin. change]" + }, + { + "type": "image", + "bbox": [ + 0.704, + 0.522, + 0.831, + 0.618 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.084, + 0.65, + 0.885, + 0.679 + ], + "angle": 0, + "content": "(c) t-SNE [27] visualizations of hidden features of FHD and our model. In the plots (c.1) and (c.3), colors correspond to the semantic classes of \\( m1 \\), whereas in (c.2) and (c.4), colors encode the binary change ground truth \\( b \\) (change, no change)." + }, + { + "type": "image_caption", + "bbox": [ + 0.234, + 0.69, + 0.735, + 0.707 + ], + "angle": 0, + "content": "Figure 4: Qualitative results and insights for a sample of DynamicEarthNet." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.731, + 0.196, + 0.747 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.903 + ], + "angle": 0, + "content": "In this paper, we have introduced Conditional Change Detection, a new paradigm for change detection. We have shown that using available pre-change semantic information as input leads to significant improvements over existing methods for change detection. This holds even for a simple baseline that solely relies on feature concatenation. To further improve the performance, we have proposed MapFormer, a novel architecture outperforming its competitors in all considered settings. A limitation of our approach is" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.733, + 0.892, + 0.9 + ], + "angle": 0, + "content": "the requirement of semantic pre-change information. In the future, we plan to mitigate this dependency by leveraging pre-trained models to generate pre-change maps via transfer learning. Further, we see room for improvement w.r.t. the semantic segmentation pipeline of our approach if more sophisticated techniques are integrated for this purpose. We hope this work will lead to further research following the avenue of Conditional Change Detection. In particular, we believe that more diverse datasets, more sophisticated methods, and other settings, such as uni-temporal supervision as in [33], will greatly benefit this line of research." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16844" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.115, + 0.47, + 0.184 + ], + "angle": 0, + "content": "[1] Nicolas Audebert, Bertrand Le Saux, and Sébastien Lefèvre. Joint learning from earth observation and openstreetmap data to get faster better semantic maps. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 67-75, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.185, + 0.47, + 0.227 + ], + "angle": 0, + "content": "[2] Wele Gedara Chaminda Bandara and Vishal M Patel. A transformer-based siamese network for change detection. arXiv preprint arXiv:2201.01293, 2022. 1, 2, 3, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.228, + 0.47, + 0.282 + ], + "angle": 0, + "content": "[3] Favyen Bastani and Samuel Madden. Beyond road extraction: A dataset for map update using aerial images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 11905-11914, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.284, + 0.47, + 0.34 + ], + "angle": 0, + "content": "[4] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In European conference on computer vision, pages 213-229. Springer, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.341, + 0.47, + 0.382 + ], + "angle": 0, + "content": "[5] Hao Chen, Zipeng Qi, and Zhenwei Shi. Remote sensing image change detection with transformers. IEEE Transactions on Geoscience and Remote Sensing, 60:1-14, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.383, + 0.47, + 0.424 + ], + "angle": 0, + "content": "[6] Hao Chen and Zhenwei Shi. A spatial-temporal attention-based method and a new dataset for remote sensing image change detection. Remote Sensing, 12(10):1662, 2020. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.425, + 0.47, + 0.48 + ], + "angle": 0, + "content": "[7] Rodrigo Caye Daudt, Bertr Le Saux, and Alexandre Boulch. Fully convolutional siamese networks for change detection. In 2018 25th IEEE International Conference on Image Processing (ICIP), pages 4063-4067. IEEE, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.481, + 0.47, + 0.536 + ], + "angle": 0, + "content": "[8] Rodrigo Caye Daudt, Bertrand Le Saux, Alexandre Boulch, and Yann Gousseau. Multitask learning for large-scale semantic change detection. Computer Vision and Image Understanding, 187:102783, 2019. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.537, + 0.47, + 0.619 + ], + "angle": 0, + "content": "[9] Sandra Díaz, Josef Settele, Eduardo S Brondízio, Hien T Ngo, John Agard, Almut Arneth, Patricia Balvanera, Kate A Brauman, Stuart HM Butchart, Kai MA Chan, et al. Pervasive human-driven decline of life on earth points to the need for transformative change. Science, 366(6471):eaax3100, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.621, + 0.47, + 0.703 + ], + "angle": 0, + "content": "[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.705, + 0.47, + 0.746 + ], + "angle": 0, + "content": "[11] Sheng Fang, Kaiyu Li, and Zhe Li. Changer: Feature interaction is what you need for change detection. arXiv preprint arXiv:2209.08290, 2022. 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.747, + 0.47, + 0.801 + ], + "angle": 0, + "content": "[12] Sheng Fang, Kaiyu Li, Jinyuan Shao, and Zhe Li. Snunet-cd: A densely connected siamese network for change detection of vhr images. IEEE Geoscience and Remote Sensing Letters, 19:1-5, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.803, + 0.47, + 0.858 + ], + "angle": 0, + "content": "[13] Shunping Ji, Shiqing Wei, and Meng Lu. Fully convolutional networks for multisource building extraction from an open aerial and satellite imagery data set. IEEE Transactions on Geoscience and Remote Sensing, 57(1):574-586, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.86, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[14] Huiwei Jiang, Min Peng, Yuanjun Zhong, Haofeng Xie, Zemin Hao, Jingming Lin, Xiaoli Ma, and Xiangyun Hu. A survey on deep learning-based change detection from" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.115, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "high-resolution remote sensing images. Remote Sensing, 14(7):1552, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.121, + 0.892, + 0.162 + ], + "angle": 0, + "content": "[15] Lazhar Khelifi and Max Mignotte. Deep learning for change detection in remote sensing images: Comprehensive review and meta-analysis. IEEE Access, 8:126385-126400, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.163, + 0.892, + 0.231 + ], + "angle": 0, + "content": "[16] Weijia Li, Conghui He, Jiarui Fang, Juepeng Zheng, Haohuan Fu, and Le Yu. Semantic segmentation-based building footprint extraction using very high-resolution satellite images and multi-source gis data. Remote Sensing, 11(4):403, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.232, + 0.892, + 0.302 + ], + "angle": 0, + "content": "[17] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF international conference on computer vision, pages 10012-10022, 2021. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.302, + 0.892, + 0.372 + ], + "angle": 0, + "content": "[18] Hyeoncheol Noh, Jingi Ju, Minseok Seo, Jongchan Park, and Dong-Geol Choi. Unsupervised change detection based on image reconstruction loss. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1352–1361, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.372, + 0.892, + 0.413 + ], + "angle": 0, + "content": "[19] Gensheng Pei and Lulu Zhang. Feature hierarchical differentiation for remote sensing image change detection. IEEE Geoscience and Remote Sensing Letters, 2022. 2, 3, 4, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.414, + 0.892, + 0.483 + ], + "angle": 0, + "content": "[20] Minseok Seo, Hakjin Lee, Yongjin Jeon, and Junghoon Seo. Self-pair: Synthesizing changes from single source for object change detection in remote sensing imagery. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 6374-6383, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.484, + 0.892, + 0.538 + ], + "angle": 0, + "content": "[21] Li Shen, Yao Lu, Hao Chen, Hao Wei, Donghai Xie, Jiabao Yue, Rui Chen, Shouye Lv, and Bitao Jiang. S2looking: A satellite side-looking dataset for building change detection. Remote Sensing, 13(24):5094, 2021. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.539, + 0.892, + 0.608 + ], + "angle": 0, + "content": "[22] Nian Shi, Keming Chen, and Guangyao Zhou. A divided spatial and temporal context network for remote sensing change detection. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 15:4897-4908, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.609, + 0.892, + 0.691 + ], + "angle": 0, + "content": "[23] Wojciech Sirko, Sergii Kashubin, Marvin Ritter, Abigail Annkah, Yasser Salah Eddine Bouchareb, Yann Dauphin, Daniel Keysers, Maxim Neumann, Moustapha Cisse, and John Quinn. Continental-scale building detection from high resolution satellite imagery. arXiv preprint arXiv:2107.12283, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.692, + 0.892, + 0.761 + ], + "angle": 0, + "content": "[24] D. M. Theobald, C. Kennedy, B. Chen, J. Oakleaf, S. Baruch-Mordo, and J. Kiesecker. Earth transformed: detailed mapping of global human modification from 1990 to 2017. Earth System Science Data, 12(3):1953-1972, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.762, + 0.892, + 0.803 + ], + "angle": 0, + "content": "[25] Zhi Tian, Chunhua Shen, and Hao Chen. Conditional convolutions for instance segmentation. In European conference on computer vision, pages 282-298. Springer, 2020. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.804, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[26] Aysim Toker, Lukas Kondmann, Mark Weber, Marvin Eisenberger, Andrés Camero, Jingliang Hu, Ariadna Pregel Hoderlein, Caglar Şenaras, Timothy Davis, Daniel Cremers, et al. Dynamicearthnet: Daily multi-spectral satellite dataset for semantic change segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 21158-21167, 2022. 1, 2, 3, 5, 7" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16845" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.468, + 0.133 + ], + "angle": 0, + "content": "[27] Laurens Van der Maaten and Geoffrey Hinton. Visualizing data using t-sne. Journal of machine learning research, 9(11), 2008. 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.136, + 0.469, + 0.19 + ], + "angle": 0, + "content": "[28] Tete Xiao, Yingcheng Liu, Bolei Zhou, Yuning Jiang, and Jian Sun. Unified perceptual parsing for scene understanding. In Proceedings of the European conference on computer vision (ECCV), pages 418-434, 2018. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.193, + 0.469, + 0.261 + ], + "angle": 0, + "content": "[29] Enze Xie, Wenhai Wang, Zhiding Yu, Anima Anandkumar, Jose M Alvarez, and Ping Luo. Segformer: Simple and efficient design for semantic segmentation with transformers. Advances in Neural Information Processing Systems, 34:12077-12090, 2021. 2, 3, 4, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.264, + 0.469, + 0.345 + ], + "angle": 0, + "content": "[30] Lingfeng Yang, Xiang Li, Renjie Song, Borui Zhao, Jun-tian Tao, Shihao Zhou, Jiajun Liang, and Jian Yang. Dynamic mlp for fine-grained image classification by leveraging geographical and temporal information. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10945-10954, 2022. 4, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.348, + 0.469, + 0.429 + ], + "angle": 0, + "content": "[31] Chenxiao Zhang, Peng Yue, Deodato Tapete, Liangcun Jiang, Boyi Shangguan, Li Huang, and Guangchao Liu. A deeply supervised image fusion network for change detection in high resolution bi-temporal remote sensing images. ISPRS Journal of Photogrammetry and Remote Sensing, 166:183-200, 2020. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.432, + 0.469, + 0.527 + ], + "angle": 0, + "content": "[32] Sixiao Zheng, Jiachen Lu, Hengshuang Zhao, Xiatian Zhu, Zekun Luo, Yabiao Wang, Yanwei Fu, Jianfeng Feng, Tao Xiang, Philip HS Torr, et al. Rethinking semantic segmentation from a sequence-to-sequence perspective with transformers. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 6881-6890, 2021. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.53, + 0.469, + 0.598 + ], + "angle": 0, + "content": "[33] Zhuo Zheng, Ailong Ma, Liangpei Zhang, and Yanfei Zhong. Change is everywhere: Single-temporal supervised object change detection in remote sensing imagery. In Proceedings of the IEEE/CVF international conference on computer vision, pages 15193-15202, 2021. 2, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.601, + 0.469, + 0.669 + ], + "angle": 0, + "content": "[34] Zongwei Zhou, Md Mahfuzur Rahman Siddiquee, Nima Tajbakhsh, and Jianming Liang. Unet++: A nested u-net architecture for medical image segmentation. In Deep learning in medical image analysis and multimodal learning for clinical decision support, pages 3-11. Springer, 2018. 2" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.669 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.956 + ], + "angle": 0, + "content": "16846" + } + ] +] \ No newline at end of file diff --git a/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/8472e89b-fe96-412d-8c9c-414b2c42d2f3_origin.pdf b/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/8472e89b-fe96-412d-8c9c-414b2c42d2f3_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..a47fbf9de759c344bac1374ba8129c54445d6f2e --- /dev/null +++ b/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/8472e89b-fe96-412d-8c9c-414b2c42d2f3_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:e7fbafc500cba5836dad855b44d386690247eb9f3abc9f1aba76958140f3451e +size 2097275 diff --git a/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/full.md b/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/full.md new file mode 100644 index 0000000000000000000000000000000000000000..89c5a0143d285c8b88cb16e6ab6271c13cec926c --- /dev/null +++ b/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/full.md @@ -0,0 +1,231 @@ +# MapFormer: Boosting Change Detection by Using Pre-change Information + +Maximilian Bernhard, Niklas Strauß, Matthias Schubert LMU Munich, MCML + +{bernhard,strauss, schubert}@dbs.ifi.lmu.de + +# Abstract + +Change detection in remote sensing imagery is essential for a variety of applications such as urban planning, disaster management, and climate research. However, existing methods for identifying semantically changed areas overlook the availability of semantic information in the form of existing maps describing features of the earth's surface. In this paper, we leverage this information for change detection in bi-temporal images. We show that the simple integration of the additional information via concatenation of latent representations suffices to significantly outperform state-of-the-art change detection methods. Motivated by this observation, we propose the new task of Conditional Change Detection, where pre-change semantic information is used as input next to bi-temporal images. To fully exploit the extra information, we propose MapFormer, a novel architecture based on a multi-modal feature fusion module that allows for feature processing conditioned on the available semantic information. We further employ a supervised, cross-modal contrastive loss to guide the learning of visual representations. Our approach outperforms existing change detection methods by an absolute $11.7\%$ and $18.4\%$ in terms of binary change IoU on DynamicEarthNet and HRSCD, respectively. Furthermore, we demonstrate the robustness of our approach to the quality of the pre-change semantic information and the absence pre-change imagery. The code is available at https://github.com/mxbh/mapformer. + +# 1. Introduction + +Earth observation data has become increasingly available in recent years, providing valuable insights into various fields such as climate research, disaster management, and urban planning. In the course of this, enormous efforts have been made towards creating rich semantic maps of the earth. For instance, OpenStreetMap provides vast amounts of data containing manual annotations around the globe. In addition, deep learning techniques are nowadays used to produce semantic map data at a large scale, e.g., [23] + +![](images/e571ddac50674f8ec2c15b94217361d0051c77c0670b625f0cd376216b1dc01d.jpg) +Figure 1: Advantage of our approach over existing change detection methods (represented by ChangeFormer [2] here) on a sample of DynamicEarthNet [26]. Employing semantic pre-change information allows to extract better features and improves change detection quality. + +generated building footprints for the entire African continent. As a result, we live in a world that has been extensively mapped. However, we live in a constantly changing world where the earth's surface is subject to various influences. These influences can be natural, e.g., earthquakes, extreme weather, floods, wildfires, and changes in vegetation, but also directly caused by humans, e.g., building construction, deforestation, and agriculture. In fact, the impact of civilization on our planet has never been higher than in recent years, with drastic consequences for ecosystems and wildlife [9, 24]. Therefore, monitoring changes in the earth's surface with up-to-date earth observation data is becoming increasingly important. + +In technical terms, this challenge is addressed by the task of change detection, where bi-temporal images are compared in order to segment pixels that have semanti- + +cally changed. Today, deep-learning-based methods for change detection achieve state-of-the-art performance [14, 15]. However, the research community so far mostly ignored the fact that existing semantic information like maps may be employed for change detection. To the best of our knowledge, semantic map information has been considered an additional input next to bi-temporal images for detecting change only for the specific task of updating road networks [3]. Although this approach is only possible if semantic information for the area of interest is available, we argue that maps are available for most parts of the world today. Alternatively, pre-trained neural networks can be used to generate a map containing the features of interest. Furthermore, when updating a map, a pre-change version of the map has to be available in the first place. + +In this paper, we tap into this direction in a general way and establish the novel task of Conditional Change Detection (see Figure 1). We demonstrate that the usage of semantic information in form of a pixelwise map has a strong impact on change detection by showing that a simple baseline (concatenating bi-temporal image features and map features) is already able to outperform state-of-the-art change detection methods, which do not use semantic pre-change information. Furthermore, we propose MapFormer, a novel architecture to fully exploit the additional information. At its core, we integrate a newly designed multi-modal feature fusion module based on the idea that the pre-change semantics should dynamically influence the processing of hidden features. Additionally, we apply a supervised contrastive loss on the learned image features, guiding the image encoder during training and further improving the performance. We also show that our approach can be applied without bi-temporal imagery, detecting change by only processing a pre-change map and current imagery. We call this task Cross-modal Change Detection. We conduct experiments on the publicly available and challenging datasets DynamicEarthNet [26] and HRSCD [8]. + +To sum up, our main contributions are as follows: + +- We investigate the novel tasks of Conditional Change Detection and Cross-modal Change Detection and introduce simple baselines that outperform state-of-the-art change detection methods. +- We propose MapFormer, a novel architecture consisting of a multi-modal feature fusion module and a supervised contrastive loss, allowing us to effectively merge image features and semantic information. +- We conduct detailed experiments and ablations demonstrating our approach's consistent performance gains, robustness, and practicability. + +# 2. Related Work + +Change detection in remote sensing images has attracted much attention over the last years, resulting in numerous + +publications in this field [14, 15, 19, 2, 11, 12, 33, 18, 20]. Most state-of-the-art methods employ deep learning and introduce various sophisticated ways of merging bi-temporal image features. For instance, [7] proposes a series of fully convolutional architectures for change detection that rely on different fusion mechanisms for the bi-temporal image features. Furthermore, [12] uses NestedUNet [34] in combination with channel attention. With the introduction of transformer architectures into computer vision [10, 4, 29], recent architectures for change detection also utilize attention blocks. BiT [5] was the first of these methods, combining a CNN backbone with cross-attention layers in the decoder head. Subsequently, works like CDViT [22], ChangeFormer [2], FHD [19], and Changer [11] use the attention mechanism in various forms, pushing the state-of-the-art in bi-temporal change detection even further. Our general architecture is inspired by ChangeFormer and FHD, which adopt the MiT backbone and the MLP head from SegFormer [29] and add specialized mechanisms to fuse the bi-temporal image features. + +LEVIR-CD [6], DSIFN-CD [31], WHU [13], and S2Looking [21] are common benchmark datasets for bi-temporal change detection, where networks are provided with co-registered, bi-temporal images as input and have to predict a pixelwise, binary change mask. Recently, a new dataset for change detection has been published with DynamicEarthNet [26], which surpasses previous datasets in terms of volume and diversity. In addition, models have to predict semantic segmentation masks containing the land cover classes next to the binary change masks for this dataset. However, none of these methods or datasets consider inputs other than bi- or multi-temporal images. Thus, previous approaches ignore the fact that pre-change semantic information for the area of interest is often available. For semantic segmentation on the other hand, it has been shown that semantic maps extracted from geographic information systems (GIS) can be effectively used to improve segmentation quality [1, 16]. In a change detection setting, only for the specific task of road network extraction [3] challenged the community to come up with solutions for updating road networks when pre-change road networks are given. Consequently, their approach considers graph data as input and output. In contrast, we consider the pixelwise change detection task when pre-change semantic information in the form of a pixelwise map is available and show that this paradigm opens up exciting new possibilities. + +# 3. Conditional Change Detection + +We consider two points in time $t_1$ (pre-change) and $t_2$ (post-change). Correspondingly, we have two image versions $I^{(1)}$ and $I^{(2)}$ for the same geographic location at $t_1$ and $t_2$ , respectively. The ground-truth binary mask $b$ indicates which pixels in the images have changed semanti + +
TaskInput I(1)I(2)m(1)Output b m(2)
Bi-temp. Bin. Change Det. (BCD)✓✓✓
Bi-temp. Sem. Change Det. (SCD)✓✓✓
[ new]Conditional BCD✓✓✓
[ new]Conditional SCD✓✓✓
[ new]Cross-modal BCD✓✓
[ new]Cross-modal SCD✓✓
+ +Table 1: Inputs and outputs for different change detection tasks. + +cally between $t_1$ and $t_2$ . Furthermore, we consider semantic maps $m^{(1)}$ and $m^{(2)}$ containing the semantic class $c \in \mathcal{C}$ for each pixel in $I^{(1)}$ and $I^{(2)}$ , respectively. Thus, $b$ can be obtained from $m^{(1)}$ and $m^{(2)}$ via a pixelwise inequality operation. As we propose new tasks in this paper (Conditional Change Detection and Cross-modal Change Detection), we provide a differentiated description of the existing and novel tasks here. An overview can be seen in Table 1. + +Existing Tasks In general, change detection tasks differ in two aspects: input and output. We can distinguish w.r.t. the output between binary and semantic change detection (BCD and SCD) for every combination of inputs. In BCD, the goal is to predict the binary change mask $\hat{b}$ , indicating which pixels have changed semantically. SCD was recently proposed in [26] and constitutes an extension of BCD. Here, not only the binary change mask $\hat{b}$ is predicted, but also the semantic segmentation $\hat{m}^{(2)}$ of the post-change image $I^{(2)}$ . This allows us to tell which regions have changed and how they have changed. The corresponding evaluation metric $SCS$ proposed in [26] combines the binary change IoU $BC$ and the semantic change metric $SC$ as their arithmetic mean. The semantic change metric $SC$ is the standard mIoU from semantic segmentation, except that it is computed only on the pixels that have changed, i.e. + +$$ +S C = \frac {1}{| \mathcal {C} |} \sum_ {c \in \mathcal {C}} \frac {| \{b = 1 \} \cap \{m ^ {(2)} = c \} \cap \{\hat {m} ^ {(2)} = c \} |}{| \{b = 1 \} \cap (\{m ^ {(2)} = c \} \cup \{\hat {m} ^ {(2)} = c \}) |}, +$$ + +$$ +B C = I o U (b, \hat {b}) \quad \text {a n d} \quad S C S = \frac {B C + S C}{2} \tag {1} +$$ + +Regarding the input, the existing settings consider bi-temporal images $I^{(1)}$ and $I^{(2)}$ . Thus, we will refer to the existing tasks as bi-temporal BCD and bi-temporal SCD. + +Conditional Change Detection While the aforementioned change detection tasks assume bi-temporal images as input, semantic information in the form of a segmentation map $m^{(1)}$ at $t_1$ may be employed additionally. That is, given pre- and post-change images together with pre-change semantic information $m^{(1)}$ , the goal is to predict the binary change mask $\hat{b}$ for Conditional BCD (as well as the semantic segmentation map $\hat{m}^{(2)}$ for Conditional SCD). + +Cross-modal Change Detection When pre-change semantic maps are available, change detection can also be conducted without bi-temporal, but solely uni-temporal imagery. In this case, only comparing the semantic information $m^{(1)}$ and the current imagery $I^{(2)}$ can suffice to detect semantic changes. In other words, this setting corresponds to Conditional Change Detection with uni-temporal images. We call this task Cross-modal Change Detection as the change has to be detected across different modalities (semantic pre-change map and post-change image). + +# 4. MapFormer + +# 4.1. Overall Architecture + +To handle these new tasks, we propose a framework, which is inspired by [19, 2] (see Figure 2). We feed the images $I^{(1)}$ and $I^{(2)}$ through the same backbone to obtain multi-scale feature maps $f^{(1)}$ and $f^{(2)}$ . For each scale, we have a separate fusion module (see Section 4.2) that handles the features from $f^{(1)}$ and $f^{(2)}$ at the corresponding scale. In addition to the image features, in our setting, we also feed semantic information in the form of an encoded map $g^{(1)}$ into the fusion modules. These map features are obtained from $m^{(1)}$ via a shallow encoder (see Section 4.4). The outputs of the fusion modules are then multi-scale features $f$ , containing information of both points in time $t_1$ and $t_2$ . Thus, we can use them in a prediction head to output the binary change map $\hat{b}$ . In terms of architecture, this prediction head is a standard semantic segmentation head [29]. Furthermore, we apply a contrastive loss on the image features $f^{(1)}$ and $f^{(2)}$ , which helps the model to learn semantically more meaningful representations (see Section 4.3). + +For many applications, it may be interesting to determine into which semantic class a pixel has changed. In this case, we also need to derive a semantic segmentation map $\hat{m}^{(2)}$ for $I^{(2)}$ . We can accomplish this either by feeding the unitemporal features $f^{(2)}$ into a separate head for semantic segmentation or by predicting both $\hat{b}$ and $\hat{m}^{(2)}$ based on the merged features $f$ . We analyze both variants in Section 5.5. Training a semantic segmentation head on uni-temporal image features also allows applying the trained model without pre-change information as we can use the predicted semantic segmentation $\hat{m}^{(1)}$ instead of $m^{(1)}$ . Results for this setting are provided in Section 5.3. Furthermore, for Cross-modal Change Detection, the design of our fusion module (described next) enables us to omit the image features $f^{(1)}$ from $I^{(1)}$ . We evaluate this setting in Section 5.4. + +# 4.2. Multi-modal Feature Fusion + +The main challenge in bi-temporal change detection is to design an effective method for fusing the bi-temporal image features. In the case of Conditional (and Cross-modal) Change Detection, we additionally have to bring together + +![](images/074a10110bb3b7794f64e422b247497d9e12c3d442a445a87c2155037dfc802f.jpg) +Figure 2: The proposed MapFormer framework consists of two main components: a novel fusion module, which combines inputs from different points in time and modalities, and a contrastive loss module, which is only used during training. + +![](images/c49cdb411da3fc8dd0179dade9c79825fee0ef4c769bec92907a13aa3867c444.jpg) +Figure 3: Our multi-modal feature fusion module for fusing bi-temporal image features and semantic input features. + +different modalities, i.e., the image features and the available semantic information. To this end, we propose a novel multi-modal feature fusion module. Subsequently, we follow [19, 29] and assume that the spatial context is encoded within the backbone, so we only consider pointwise operations, treating each spatial location separately. + +A standard way of merging multi-modal features is a simple concatenation along the channel dimension. However, we argue that the semantic information in our setting can be used more effectively if we use it to modulate the features dynamically. Thus, the given information should influence the processing of image features and thereby improve perception. Such data-dependent feature processing can be achieved by dynamically predicting the weights of one or more layers from the features themselves [30, 25]. While such techniques are powerful, they come at a significant computational cost. In fact, applying a method like DynamicMLP [30] to a segmentation task like ours by predicting dynamic weights for each pixel separately is intractable without drastically reducing the number of channels (or the spatial resolution). Therefore, we resort to a restricted attention-style approach. More precisely, to keep + +the computational cost tractable, we restrict the attention to a set of $K$ values for each output dimension, thereby greatly reducing the complexity compared to unrestricted attention. + +A visualization of our proposed multi-modal feature fusion module can be seen in Figure 3. First, we concatenate the bi-temporal features $f_{(i,j)}^{(1)}$ and $f_{(i,j)}^{(2)}$ and the map feature $g_{(i,j)}^{(1)}$ for each spatial location $(i,j)$ . This concatenated feature is fed through $K$ separate MLPs (implemented with grouped, pointwise convolutions) to obtain $K$ joint representations $(h_{k(i,j)})_{k=1\dots K}$ with $D_f$ channels. Here, $D_f$ refers to the dimensionality of $f_{(i,j)}^{(t)}, t = 1,2$ , and $K$ is a hyperparameter for tuning the semantic variety. These $K$ joint representations $(h_{k(i,j)})_{k=1\dots K}$ can be interpreted as views, encoding different aspects of the same spatial location. To associate the map information $g_{(i,j)}^{(1)}$ with these views, we employ a channelwise attention mechanism. In particular, we compute attention weights by feeding the map features $g_{(i,j)}^{(1)}$ into an additional MLP. The result of shape $K\times D_f$ is softmaxed over the $K$ -dimension providing a matrix of attention scores with entries $a_{(i,j,k,d)}$ for location $(i,j)$ . Thus, each channel of the module output $f_{(i,j)}$ separately attends to the $K$ joint representations $(h_{k(i,j)})_{k=1\dots K}$ . In mathematical terms, we compute + +$$ +f _ {(i, j)} = \left(\sum_ {k = 1 \dots K} a _ {(i, j, k, d)} h _ {k (i, j, d)}\right) _ {d = 1 \dots D _ {f}} \tag {2} +$$ + +The merged features $f_{(i,j)}$ are then collected for the different scales of the backbone feature maps and passed to the prediction head. + +# 4.3. Contrastive Loss + +For unchanged areas, we want $f^{(1)}, f^{(2)}$ , and $g^{(1)}$ to encode the same semantic concepts. For changed areas how- + +ever, the encoded information in $f^{(1)}$ and $g^{(1)}$ should be similar, while $f^{(2)}$ should be dissimilar from the two. Based on this observation, we design a supervised contrastive loss that forces the network to learn better image features. More precisely, we apply a learnable projection $\pi$ to map $f^{(1)}$ and $f^{(2)}$ into the feature space of $g^{(1)}$ . Then, we compute our contrastive loss as follows: + +$$ +\begin{array}{l} \mathcal {L} _ {(i, j)} ^ {(c o n t r)} = - \operatorname {s i m} \left(g _ {(i, j)} ^ {(1)}, \pi \left(f _ {(i, j)} ^ {(1)}\right)\right) \tag {3} \\ + \left\{ \begin{array}{l l} - \operatorname {s i m} \left(g _ {(i, j)} ^ {(1)}, \pi \big (f _ {(i, j)} ^ {(2)} \big)\right), & b _ {(i, j)} = 0 \\ \max \left(\operatorname {s i m} \left(g _ {(i, j)} ^ {(1)}, \pi \big (f _ {(i, j)} ^ {(2)} \big)\right), 0\right), & b _ {(i, j)} = 1. \end{array} \right. \\ \end{array} +$$ + +Here, $\operatorname{sim}(\cdot, \cdot)$ denotes the cosine similarity, and the loss is ultimately aggregated over all pixel locations $(i,j)$ . Interestingly, we found it beneficial not to use a projection for $g^{(1)}$ and also not to backpropagate gradients coming from the contrastive loss through $g^{(1)}$ . Details can be found in Section 5.3. + +# 4.4. Architecture Details + +Like [19], we use the MixVisionTransformer from [29] as image encoder backbone. Due to the spatial attention in the encoder, the features $f_{(i,j)}^{(t)}$ are already contextualized, and a pointwise prediction head after a pointwise fusion module suffices to produce high-quality predictions. We leave SegFormer's prediction head unchanged and solely plug in our proposed feature fusion module between the backbone and the head. Thus, our module can be easily combined with other architectures. Inside our feature fusion module, the merged features $(h_k)_{k=1\dots K}$ are produced by $K$ two-layer MLPs, while the attention weights $a$ are predicted from $g^{(1)}$ via a linear layer. To encode the semantic information $m^{(1)}$ into $g^{(1)}$ , we use a three-layer CNN with a pointwise convolution followed by two convolutions with a kernel size of five and a dilation of two to increase the receptive field. When fusing the encoded map $g^{(1)}$ , we use bilinear interpolation to comply with the different spatial resolutions of the different scales of the image feature maps. The projection head $\pi$ for the contrastive loss is a pointwise MLP head in the style of SegFormer's prediction head. The overall training loss is the sum of our contrastive loss and the cross-entropy loss for the binary change map (as well as the semantic segmentation in SCD). + +# 5. Experiments + +# 5.1. Datasets + +Since Conditional Change Detection requires semantic segmentation maps, which are not included in commonly used benchmark datasets such as LEVIR-CD [6], DSIFN-CD [31], and S2Looking [21], we conduct our experiments on DynamicEarthNet [26] and HRSCD [8]. DynamicEarthNet is a recent dataset consisting of daily images of 75 areas + +of interest (AOIs) over a span of two years. Ground-truth annotations containing the seven land use classes "impervious surface", "agriculture", "forest & other vegetation", "wetlands", "soil", "water", and "snow & ice" are only available for the first day of each month and 55 AOIs. As our setting assumes semantic information as input, we only use the images with available annotations and selected 35, 10, and 10 AOIs for training, validation, and testing, respectively. Following [26], we omit the class "snow & ice" from the evaluation because it only occurs in two AOIs. Targets for binary change detection were created by applying a pixelwise inequality on pairs of ground-truth semantic maps. + +The High-Resolution Semantic Change Detection (HRSCD) dataset was proposed in [8]. It contains 291 pairs of images, where the first was acquired in 2005/2006 and the second in 2012. Semantic ground-truth segmentation maps and binary change segmentation maps are available for all samples. The semantic classes are "artificial surface", "agricultural area", "forest", "wetland", and "water". We selected 191, 50, and 50 pairs for training, validation, and testing, respectively. Further details on both datasets can be found in the supplementary material. + +# 5.2. Baselines + +As baselines derived from semantic segmentation models, we employ SegFormer [29], Swin + UPerNet [17, 28], and SETR-PUP [32] for change detection by taking the pixelwise inequality of the predicted semantic segmentations $\hat{m}^{(1)}$ and $\hat{m}^{(2)}$ as binary change prediction. The concatenation baseline for bi-temporal BCD resembles the SegFormer architecture, but concatenates the image features $f^{(1)}$ and $f^{(2)}$ before passing them to a head that directly predicts the binary change map. These baselines can be easily reused for Conditional BCD. For the semantic segmentation baselines, we apply the pixelwise inequality to $m^{(1)}$ and $\hat{m}^{(2)}$ instead of $\hat{m}^{(1)}$ and $\hat{m}^{(2)}$ . For the concatenation baseline, we concatenate map features $g^{(1)}$ extracted by a map encoder as described in Section 4.4 to the image features $f^{(1)}$ and $f^{(2)}$ . As state-of-the-art methods for bi-temporal BCD, we select FHD [19], ChangerEx [11], and ChangeFormer [2] as they are recent and have been shown to perform best on the common benchmarks. We also extend these methods for Conditional BCD by concatenating map features to merged bi-temporal image features. Further, we consider another baseline for Conditional BCD, which has a separate concatenation-based BCD head for every semantic class such that the final change prediction can be taken from the head corresponding to the pre-change semantic class for every pixel. To have a strong competitor for our feature fusion module, we also use a pixel-wise Dynamic MLP-C [30] for fusing semantic input with image features. For training details as well as a comparison of model sizes, we refer to the supplementary material. + +
MethodDynENetHRSCD
F1IoUF1IoU
Bi-temporal BCD:
SegFormer [29]20.311.317.89.7
Swin + UPerNet [17, 28]20.111.117.69.7
SETR-PUP [32]19.410.814.88.0
Concatenation20.711.641.225.9
FHD [19]17.29.445.229.2
ChangerEx [11]21.111.837.022.7
ChangeFormer [2]20.711.545.729.6
MapFormerK=10 (w/o m(1))28.616.743.928.2
Conditional BCD:
SegFormer [29]21.211.95.62.8
Swin + UPerNet [17, 28]21.812.25.62.8
SETR-PUP [32]20.811.65.42.8
Concatenation33.520.162.145.1
FHD [19] + Concat.33.219.961.244.1
ChangerEx [11] + Concat.30.918.358.141.0
ChangeFormer [2] + Concat.31.418.661.544.4
Classwise CD-Heads37.022.762.345.3
DynamicMLP [30]34.520.862.745.7
MapFormerK=534.821.164.948.0
MapFormerK=1038.023.564.547.7
MapFormerK=1536.422.264.547.6
Ablations (MapFormerK=10):
w/o constrastive34.520.963.846.8
w/o stop-gradient36.722.562.545.4
w/ map proj.35.821.860.745.9
high-level info29.817.664.447.5
low-res. info30.417.960.343.2
+ +Table 2: (Conditional) Binary Change Detection as well as ablations. Our method performs best and is still highly competitive without ground-truth semantic input. + +# 5.3. Binary Change Detection + +Overall Performance In BCD, there is only a single objective (binary change IoU); thus, our approach can be best compared to other methods. In Table 2, we present BCD results for baselines, state-of-the-art methods, and our method. It is evident that Conditional BCD greatly outperforms all existing bi-temporal methods - even with the simple concatenation baseline (11.8% vs. 20.1% and 29.6% vs. 45.1% IoU, resp.). MapFormer further pushes the performance on both datasets to 23.5% and 48.0% IoU, respectively. Particularly, our method also outperforms DynamicMLP [30], a state-of-the-art method for multi-modal feature fusion. This holds for all tested values of our only hyperparameter $K$ and even without our contrastive loss (see Ablations). Remarkably, when MapFormer is applied without the true map $m^{(1)}$ , but only predicted segmentation + +maps $\hat{m}^{(1)}$ ( $w / o m^{(1)}$ ), the performance is still highly competitive, even achieving by far the best performance among the bi-temporal methods on DynamicEarthNet with an IoU of $16.7\%$ . Furthermore, it is noteworthy that the semantic segmentation baselines SegFormer, Swin + UPerNet and SETR perform poorly in Conditional BCD, especially on HRSCD. We attribute this to the fact that every misclassified pixel leads to a false positive change prediction in this setup, causing a very low precision. In bi-temporal BCD, identical classification errors in $\hat{m}^{(1)}$ and $\hat{m}^{(2)}$ may still lead to true negative change predictions. + +Ablations In the lower part of Table 2, we present several ablation experiments to analyze MapFormer's contributing factors and robustness. First, we study the effect of our design choices in the contrastive loss module. When the contrastive loss is completely omitted (w/o contrastive), performance drops on both datasets by $2.6\%$ and $0.9\%$ IoU, respectively. Furthermore, we compare MapFormer with modifications where we omitted the stop-gradient operation on the map features $g^{(1)}$ (w/o stop-gradient) and a version where we included a linear projection layer to map $g^{(1)}$ to the joint embedding space with $\pi \left(f^{(t)}\right)$ (w/ map proj.). Both variants do not reach the performance of our proposed method. Thus, we conclude that gradients coming from the contrastive loss flowing through the map features $g^{(1)}$ have a detrimental effect on their representation. + +Finally, we investigate the effect of the quality of the semantic information $m^{(1)}$ . To this end, we merge some classes in the pre-change maps to simulate that only high-level semantic information is available (high-level info). For DynamicEarthNet, we merge the classes "agriculture", "forest & other vegetation" and "soil" as well as "wetlands", "water" and "snow & ice" into two high-level classes, respectively. For HRSCD, we solely distinguish between "artificial" and "rest". Apparently, this high-level information still suffices to generate better change predictions than the bi-temporal change detection methods. However, we observe a significant performance drop on DynamicEarthNet (5.9% IoU), while the performance only degrades marginally on HRSCD (0.2% IoU). Furthermore, we simulate low-resolution semantic information by downsampling with a factor of 32 (low-res. info). Here, we can see that the performance of our method degrades with the low-resolution input (by 5.6% and 4.8% IoU, resp.). Nevertheless, it is still clearly superior to the bi-temporal change detection methods. In conclusion, our results show that the semantic input quality correlates to the Conditional Change Detection performance. However, low-quality input still suffices to achieve significantly better results than methods not relying on this kind of information. Further ablations can be found in the supplementary material. + +
MethodDynENetHRSCD
F1IoUF1IoU
SegFormer21.211.95.62.8
Swin+UPerNet21.812.25.62.8
SETR-PUP20.811.65.42.8
Concatenation31.818.961.544.4
MapFormer32.019.062.145.0
+ +
MethodDynamicEarthNetHRSCD
BCSCSCSmIoUBCSCSCSmIoU
SegFormer11.331.521.439.79.720.315.052.7
Swin + UperNet11.128.019.641.49.720.915.353.1
SETR-PUP10.826.318.538.58.521.714.950.5
MapFormer (sem. seg. on f(2))23.029.026.039.948.021.534.752.9
MapFormer (sem. seg. on f)23.113.118.161.548.212.530.472.3
MapFormer (Cross-modal)20.430.725.540.345.621.733.549.9
+ +Table 3: Cross-modal Binary Change Detection. MapFormer and the concatenation baseline outperform SegFormer. + +Table 4: (Conditional) Semantic Change Detection. Predicting $\hat{m}^{(2)}$ based on $f^{(2)}$ yields the best results w.r.t. the main objective SCS. + +# 5.4. Cross-modal Binary Change Detection + +We also evaluate MapFormer on the task of Cross-modal BCD, i.e. change detection when only post-change imagery and pre-change map information are given (see Table 3). Here, the concatenation baseline omits the pre-change image features $f^{(1)}$ . The semantic segmentation baselines are identical to the ones for Conditional BCD in Table 2 as they do not utilize $\hat{m}^{(1)}$ . Again, we can see that MapFormer performs best, although the margin to the concatenation baseline is rather small (0.1% and 0.6% IoU, resp.). However, comparing the results with those in Table 2, we observe that bi-temporal methods are greatly outperformed in this setting as well, and the performance is still relatively close to Conditional BCD, which relies on bi-temporal images. This highlights the value of semantic input for change detection and shows that bi-temporal images are not critical for change detection when pre-change maps are available. + +# 5.5. Semantic Change Detection + +For semantic change detection, one can integrate additional semantic segmentation heads into our framework. We provide the results for Conditional SCD and Cross-modal SCD in Table 4. Here, we follow the notation of [26] and denote the binary change IoU with BC (instead of IoU in Tables 2,3). In the first three rows of Table 4, we reuse the semantic segmentation baselines of Table 2. The fourth and fifth rows correspond to MapFormer, with the semantic segmentation outputs being predicted from the uni-temporal image features (sem. seg. on $f^{(2)}$ ) and the merged features (sem. seg. on $f$ ), respectively. Apparently, the version with a segmentation head applied on $f^{(2)}$ performs better w.r.t. BC, SC, and SCS, whereas the joint version is superior w.r.t. mIoU. Our reasoning is that the imbalance between changed and unchanged areas in the data causes the model using $f$ to tend to repeat the given semantic information, which is not accessible through $f^{(2)}$ . This hurts the performance on changed pixels (SC), but leads to higher overall mIoU. In the last row of Table 4, we show the results for MapFormer solely based on uni-temporal images (Cross-modal), using $f^{(2)}$ for semantic segmentation. Sim + +ilar to our observations for BCD, this model is competitive to its counterpart for Conditional SCD (25.5% vs. 26.0% and 33.5% vs. 34.7% SCS, resp.). This implies that $m^{(1)}$ has a stronger impact on the performance than $I^{(1)}$ . + +# 5.6. Qualitative Results + +The first row of Figure 4 (a) depicts inputs and ground-truth targets for a sample of DynamicEarthNet. The second row shows the binary change predictions of several methods for this sample. We can see that SegFormer suffers from many false positive predictions, while the other state-of-the-art methods struggle to detect the changed areas. In contrast, MapFormer produces a convincing change mask where only small details are missing. + +In Figure 4 (b), we visualize the attention weights of MapFormer for this sample. The visualizations correspond to the argmax over the $K$ -dimension of the attention weights $a_{(\cdot ,\cdot ,k,d)}$ for six different channels $d$ . In other words, the colors in each visualization show which of the features $(h_k)_{k = 1\dots K}$ receive most attention for the selected channels. Comparing them, we can see that the maps focus on different aspects of the semantic information $m_{1}$ . For example, the first attention map mostly resembles the original map $m^{(1)}$ , whereas the second and third visualizations resemble more coarse versions of $m_{1}$ . On the other hand, the fourth map focuses more on small and thin segments such as roads. The remaining two attention maps seem to aim at separating the features for specific semantic classes. + +To provide further insight, we compare t-SNE [27] visualizations of the hidden features of MapFormer and FHD in Figure 4 (c). Each point in the visualization represents the hidden feature for one pixel in the sample depicted in subfigure (a). For MapFormer, the feature space is much less entangled, and the semantic classes of the pixels and the binary change ground truth can be separated from other pixels relatively well. In contrast, the FHD representations for different semantic and binary change classes are highly mixed, leading to prediction errors. + +![](images/965499b0b5853f4d37485dbc7f6d85670cdccce1f7a1cdb0afdd1570476e1e13.jpg) +(a) Binary change prediction for different methods. + +![](images/f215da9a06252f105cb9e52c661bb414e15bfb7ae7fcbd70f204f2010b59bc09.jpg) +(b) Visualization of attentions weights. Colors encode which of the representations $(h_k)_{k = 1\dots K}$ received most attention for six selected channels $d$ , exhibiting a focus on different aspects of the features for different $k$ and $d$ . + +![](images/9e7969a859e4c0f6a7d292f789443c3a71f8b5c83e03d4eda5b3fb343c5a6578.jpg) +(c.1) FHD [sem. classes] + +![](images/41cfe88567adb453994f51abce1fe291fd594f3cb352c35e15e0a7ea3cc07ac3.jpg) +(c.2) FHD [bin. change] + +![](images/e204a0bb457111d50ea4db0e365d630094409670f240db1abe0b506bd29a8dea.jpg) +(c.3) MapFormer [sem. classes] (c.4) MapFormer [bin. change] +(c) t-SNE [27] visualizations of hidden features of FHD and our model. In the plots (c.1) and (c.3), colors correspond to the semantic classes of $m1$ , whereas in (c.2) and (c.4), colors encode the binary change ground truth $b$ (change, no change). + +![](images/efff98210e2b4190a39c6e3f1f7963755cf9f4a1b9791b847df15afec3e40c5e.jpg) +Figure 4: Qualitative results and insights for a sample of DynamicEarthNet. + +# 6. Conclusion + +In this paper, we have introduced Conditional Change Detection, a new paradigm for change detection. We have shown that using available pre-change semantic information as input leads to significant improvements over existing methods for change detection. This holds even for a simple baseline that solely relies on feature concatenation. To further improve the performance, we have proposed MapFormer, a novel architecture outperforming its competitors in all considered settings. A limitation of our approach is + +the requirement of semantic pre-change information. In the future, we plan to mitigate this dependency by leveraging pre-trained models to generate pre-change maps via transfer learning. Further, we see room for improvement w.r.t. the semantic segmentation pipeline of our approach if more sophisticated techniques are integrated for this purpose. We hope this work will lead to further research following the avenue of Conditional Change Detection. In particular, we believe that more diverse datasets, more sophisticated methods, and other settings, such as uni-temporal supervision as in [33], will greatly benefit this line of research. + +# References + +[1] Nicolas Audebert, Bertrand Le Saux, and Sébastien Lefèvre. Joint learning from earth observation and openstreetmap data to get faster better semantic maps. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 67-75, 2017. 2 +[2] Wele Gedara Chaminda Bandara and Vishal M Patel. A transformer-based siamese network for change detection. arXiv preprint arXiv:2201.01293, 2022. 1, 2, 3, 5, 6 +[3] Favyen Bastani and Samuel Madden. Beyond road extraction: A dataset for map update using aerial images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 11905-11914, 2021. 2 +[4] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In European conference on computer vision, pages 213-229. Springer, 2020. 2 +[5] Hao Chen, Zipeng Qi, and Zhenwei Shi. Remote sensing image change detection with transformers. IEEE Transactions on Geoscience and Remote Sensing, 60:1-14, 2021. 2 +[6] Hao Chen and Zhenwei Shi. A spatial-temporal attention-based method and a new dataset for remote sensing image change detection. Remote Sensing, 12(10):1662, 2020. 2, 5 +[7] Rodrigo Caye Daudt, Bertr Le Saux, and Alexandre Boulch. Fully convolutional siamese networks for change detection. In 2018 25th IEEE International Conference on Image Processing (ICIP), pages 4063-4067. IEEE, 2018. 2 +[8] Rodrigo Caye Daudt, Bertrand Le Saux, Alexandre Boulch, and Yann Gousseau. Multitask learning for large-scale semantic change detection. Computer Vision and Image Understanding, 187:102783, 2019. 2, 5 +[9] Sandra Díaz, Josef Settele, Eduardo S Brondízio, Hien T Ngo, John Agard, Almut Arneth, Patricia Balvanera, Kate A Brauman, Stuart HM Butchart, Kai MA Chan, et al. Pervasive human-driven decline of life on earth points to the need for transformative change. Science, 366(6471):eaax3100, 2019. 1 +[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020. 2 +[11] Sheng Fang, Kaiyu Li, and Zhe Li. Changer: Feature interaction is what you need for change detection. arXiv preprint arXiv:2209.08290, 2022. 2, 5, 6 +[12] Sheng Fang, Kaiyu Li, Jinyuan Shao, and Zhe Li. Snunet-cd: A densely connected siamese network for change detection of vhr images. IEEE Geoscience and Remote Sensing Letters, 19:1-5, 2021. 2 +[13] Shunping Ji, Shiqing Wei, and Meng Lu. Fully convolutional networks for multisource building extraction from an open aerial and satellite imagery data set. IEEE Transactions on Geoscience and Remote Sensing, 57(1):574-586, 2018. 2 +[14] Huiwei Jiang, Min Peng, Yuanjun Zhong, Haofeng Xie, Zemin Hao, Jingming Lin, Xiaoli Ma, and Xiangyun Hu. A survey on deep learning-based change detection from + +high-resolution remote sensing images. Remote Sensing, 14(7):1552, 2022. 2 +[15] Lazhar Khelifi and Max Mignotte. Deep learning for change detection in remote sensing images: Comprehensive review and meta-analysis. IEEE Access, 8:126385-126400, 2020. 2 +[16] Weijia Li, Conghui He, Jiarui Fang, Juepeng Zheng, Haohuan Fu, and Le Yu. Semantic segmentation-based building footprint extraction using very high-resolution satellite images and multi-source gis data. Remote Sensing, 11(4):403, 2019. 2 +[17] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF international conference on computer vision, pages 10012-10022, 2021. 5, 6 +[18] Hyeoncheol Noh, Jingi Ju, Minseok Seo, Jongchan Park, and Dong-Geol Choi. Unsupervised change detection based on image reconstruction loss. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1352–1361, 2022. 2 +[19] Gensheng Pei and Lulu Zhang. Feature hierarchical differentiation for remote sensing image change detection. IEEE Geoscience and Remote Sensing Letters, 2022. 2, 3, 4, 5, 6 +[20] Minseok Seo, Hakjin Lee, Yongjin Jeon, and Junghoon Seo. Self-pair: Synthesizing changes from single source for object change detection in remote sensing imagery. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 6374-6383, 2023. 2 +[21] Li Shen, Yao Lu, Hao Chen, Hao Wei, Donghai Xie, Jiabao Yue, Rui Chen, Shouye Lv, and Bitao Jiang. S2looking: A satellite side-looking dataset for building change detection. Remote Sensing, 13(24):5094, 2021. 2, 5 +[22] Nian Shi, Keming Chen, and Guangyao Zhou. A divided spatial and temporal context network for remote sensing change detection. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 15:4897-4908, 2022. 2 +[23] Wojciech Sirko, Sergii Kashubin, Marvin Ritter, Abigail Annkah, Yasser Salah Eddine Bouchareb, Yann Dauphin, Daniel Keysers, Maxim Neumann, Moustapha Cisse, and John Quinn. Continental-scale building detection from high resolution satellite imagery. arXiv preprint arXiv:2107.12283, 2021. 1 +[24] D. M. Theobald, C. Kennedy, B. Chen, J. Oakleaf, S. Baruch-Mordo, and J. Kiesecker. Earth transformed: detailed mapping of global human modification from 1990 to 2017. Earth System Science Data, 12(3):1953-1972, 2020. 1 +[25] Zhi Tian, Chunhua Shen, and Hao Chen. Conditional convolutions for instance segmentation. In European conference on computer vision, pages 282-298. Springer, 2020. 4 +[26] Aysim Toker, Lukas Kondmann, Mark Weber, Marvin Eisenberger, Andrés Camero, Jingliang Hu, Ariadna Pregel Hoderlein, Caglar Şenaras, Timothy Davis, Daniel Cremers, et al. Dynamicearthnet: Daily multi-spectral satellite dataset for semantic change segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 21158-21167, 2022. 1, 2, 3, 5, 7 + +[27] Laurens Van der Maaten and Geoffrey Hinton. Visualizing data using t-sne. Journal of machine learning research, 9(11), 2008. 7, 8 +[28] Tete Xiao, Yingcheng Liu, Bolei Zhou, Yuning Jiang, and Jian Sun. Unified perceptual parsing for scene understanding. In Proceedings of the European conference on computer vision (ECCV), pages 418-434, 2018. 5, 6 +[29] Enze Xie, Wenhai Wang, Zhiding Yu, Anima Anandkumar, Jose M Alvarez, and Ping Luo. Segformer: Simple and efficient design for semantic segmentation with transformers. Advances in Neural Information Processing Systems, 34:12077-12090, 2021. 2, 3, 4, 5, 6 +[30] Lingfeng Yang, Xiang Li, Renjie Song, Borui Zhao, Jun-tian Tao, Shihao Zhou, Jiajun Liang, and Jian Yang. Dynamic mlp for fine-grained image classification by leveraging geographical and temporal information. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10945-10954, 2022. 4, 5, 6 +[31] Chenxiao Zhang, Peng Yue, Deodato Tapete, Liangcun Jiang, Boyi Shangguan, Li Huang, and Guangchao Liu. A deeply supervised image fusion network for change detection in high resolution bi-temporal remote sensing images. ISPRS Journal of Photogrammetry and Remote Sensing, 166:183-200, 2020. 2, 5 +[32] Sixiao Zheng, Jiachen Lu, Hengshuang Zhao, Xiatian Zhu, Zekun Luo, Yabiao Wang, Yanwei Fu, Jianfeng Feng, Tao Xiang, Philip HS Torr, et al. Rethinking semantic segmentation from a sequence-to-sequence perspective with transformers. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 6881-6890, 2021. 5, 6 +[33] Zhuo Zheng, Ailong Ma, Liangpei Zhang, and Yanfei Zhong. Change is everywhere: Single-temporal supervised object change detection in remote sensing imagery. In Proceedings of the IEEE/CVF international conference on computer vision, pages 15193-15202, 2021. 2, 8 +[34] Zongwei Zhou, Md Mahfuzur Rahman Siddiquee, Nima Tajbakhsh, and Jianming Liang. Unet++: A nested u-net architecture for medical image segmentation. In Deep learning in medical image analysis and multimodal learning for clinical decision support, pages 3-11. Springer, 2018. 2 \ No newline at end of file diff --git a/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/images.zip b/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..9d9c61c065d8f04d0759685697e2148dbc70ac42 --- /dev/null +++ b/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:a735927caeb712e97fbf9ebe2ff4e08d2aecf8d2e223972a151c4a36be4ce3db +size 620862 diff --git a/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/layout.json b/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..0503f17659202169e8d0c6022d611d5fd530d4c4 --- /dev/null +++ b/2023/MapFormer_ Boosting Change Detection by Using Pre-change Information/layout.json @@ -0,0 +1,8274 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 66, + 103, + 529, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 103, + 529, + 121 + ], + "spans": [ + { + "bbox": [ + 66, + 103, + 529, + 121 + ], + "type": "text", + "content": "MapFormer: Boosting Change Detection by Using Pre-change Information" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 160, + 143, + 433, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 160, + 143, + 433, + 171 + ], + "spans": [ + { + "bbox": [ + 160, + 143, + 433, + 171 + ], + "type": "text", + "content": "Maximilian Bernhard, Niklas Strauß, Matthias Schubert LMU Munich, MCML" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 183, + 173, + 411, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 183, + 173, + 411, + 185 + ], + "spans": [ + { + "bbox": [ + 183, + 173, + 411, + 185 + ], + "type": "text", + "content": "{bernhard,strauss, schubert}@dbs.ifi.lmu.de" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "spans": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 239, + 290, + 562 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 239, + 290, + 562 + ], + "spans": [ + { + "bbox": [ + 46, + 239, + 290, + 562 + ], + "type": "text", + "content": "Change detection in remote sensing imagery is essential for a variety of applications such as urban planning, disaster management, and climate research. However, existing methods for identifying semantically changed areas overlook the availability of semantic information in the form of existing maps describing features of the earth's surface. In this paper, we leverage this information for change detection in bi-temporal images. We show that the simple integration of the additional information via concatenation of latent representations suffices to significantly outperform state-of-the-art change detection methods. Motivated by this observation, we propose the new task of Conditional Change Detection, where pre-change semantic information is used as input next to bi-temporal images. To fully exploit the extra information, we propose MapFormer, a novel architecture based on a multi-modal feature fusion module that allows for feature processing conditioned on the available semantic information. We further employ a supervised, cross-modal contrastive loss to guide the learning of visual representations. Our approach outperforms existing change detection methods by an absolute " + }, + { + "bbox": [ + 46, + 239, + 290, + 562 + ], + "type": "inline_equation", + "content": "11.7\\%" + }, + { + "bbox": [ + 46, + 239, + 290, + 562 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 239, + 290, + 562 + ], + "type": "inline_equation", + "content": "18.4\\%" + }, + { + "bbox": [ + 46, + 239, + 290, + 562 + ], + "type": "text", + "content": " in terms of binary change IoU on DynamicEarthNet and HRSCD, respectively. Furthermore, we demonstrate the robustness of our approach to the quality of the pre-change semantic information and the absence pre-change imagery. The code is available at https://github.com/mxbh/mapformer." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 586, + 128, + 597 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 586, + 128, + 597 + ], + "spans": [ + { + "bbox": [ + 47, + 586, + 128, + 597 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 605, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 287, + 715 + ], + "type": "text", + "content": "Earth observation data has become increasingly available in recent years, providing valuable insights into various fields such as climate research, disaster management, and urban planning. In the course of this, enormous efforts have been made towards creating rich semantic maps of the earth. For instance, OpenStreetMap provides vast amounts of data containing manual annotations around the globe. In addition, deep learning techniques are nowadays used to produce semantic map data at a large scale, e.g., [23]" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 310, + 213, + 544, + 419 + ], + "blocks": [ + { + "bbox": [ + 310, + 213, + 544, + 419 + ], + "lines": [ + { + "bbox": [ + 310, + 213, + 544, + 419 + ], + "spans": [ + { + "bbox": [ + 310, + 213, + 544, + 419 + ], + "type": "image", + "image_path": "e571ddac50674f8ec2c15b94217361d0051c77c0670b625f0cd376216b1dc01d.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 430, + 547, + 491 + ], + "lines": [ + { + "bbox": [ + 305, + 430, + 547, + 491 + ], + "spans": [ + { + "bbox": [ + 305, + 430, + 547, + 491 + ], + "type": "text", + "content": "Figure 1: Advantage of our approach over existing change detection methods (represented by ChangeFormer [2] here) on a sample of DynamicEarthNet [26]. Employing semantic pre-change information allows to extract better features and improves change detection quality." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 518, + 546, + 674 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 518, + 546, + 674 + ], + "spans": [ + { + "bbox": [ + 304, + 518, + 546, + 674 + ], + "type": "text", + "content": "generated building footprints for the entire African continent. As a result, we live in a world that has been extensively mapped. However, we live in a constantly changing world where the earth's surface is subject to various influences. These influences can be natural, e.g., earthquakes, extreme weather, floods, wildfires, and changes in vegetation, but also directly caused by humans, e.g., building construction, deforestation, and agriculture. In fact, the impact of civilization on our planet has never been higher than in recent years, with drastic consequences for ecosystems and wildlife [9, 24]. Therefore, monitoring changes in the earth's surface with up-to-date earth observation data is becoming increasingly important." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 677, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 547, + 715 + ], + "type": "text", + "content": "In technical terms, this challenge is addressed by the task of change detection, where bi-temporal images are compared in order to segment pixels that have semanti-" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "16837" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 251 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 251 + ], + "type": "text", + "content": "cally changed. Today, deep-learning-based methods for change detection achieve state-of-the-art performance [14, 15]. However, the research community so far mostly ignored the fact that existing semantic information like maps may be employed for change detection. To the best of our knowledge, semantic map information has been considered an additional input next to bi-temporal images for detecting change only for the specific task of updating road networks [3]. Although this approach is only possible if semantic information for the area of interest is available, we argue that maps are available for most parts of the world today. Alternatively, pre-trained neural networks can be used to generate a map containing the features of interest. Furthermore, when updating a map, a pre-change version of the map has to be available in the first place." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 252, + 289, + 514 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 252, + 289, + 514 + ], + "spans": [ + { + "bbox": [ + 46, + 252, + 289, + 514 + ], + "type": "text", + "content": "In this paper, we tap into this direction in a general way and establish the novel task of Conditional Change Detection (see Figure 1). We demonstrate that the usage of semantic information in form of a pixelwise map has a strong impact on change detection by showing that a simple baseline (concatenating bi-temporal image features and map features) is already able to outperform state-of-the-art change detection methods, which do not use semantic pre-change information. Furthermore, we propose MapFormer, a novel architecture to fully exploit the additional information. At its core, we integrate a newly designed multi-modal feature fusion module based on the idea that the pre-change semantics should dynamically influence the processing of hidden features. Additionally, we apply a supervised contrastive loss on the learned image features, guiding the image encoder during training and further improving the performance. We also show that our approach can be applied without bi-temporal imagery, detecting change by only processing a pre-change map and current imagery. We call this task Cross-modal Change Detection. We conduct experiments on the publicly available and challenging datasets DynamicEarthNet [26] and HRSCD [8]." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 59, + 515, + 259, + 526 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 515, + 259, + 526 + ], + "spans": [ + { + "bbox": [ + 59, + 515, + 259, + 526 + ], + "type": "text", + "content": "To sum up, our main contributions are as follows:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 58, + 532, + 286, + 660 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 58, + 532, + 286, + 578 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 532, + 286, + 578 + ], + "spans": [ + { + "bbox": [ + 58, + 532, + 286, + 578 + ], + "type": "text", + "content": "- We investigate the novel tasks of Conditional Change Detection and Cross-modal Change Detection and introduce simple baselines that outperform state-of-the-art change detection methods." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 58, + 578, + 286, + 624 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 578, + 286, + 624 + ], + "spans": [ + { + "bbox": [ + 58, + 578, + 286, + 624 + ], + "type": "text", + "content": "- We propose MapFormer, a novel architecture consisting of a multi-modal feature fusion module and a supervised contrastive loss, allowing us to effectively merge image features and semantic information." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 58, + 624, + 286, + 660 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 624, + 286, + 660 + ], + "spans": [ + { + "bbox": [ + 58, + 624, + 286, + 660 + ], + "type": "text", + "content": "- We conduct detailed experiments and ablations demonstrating our approach's consistent performance gains, robustness, and practicability." + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 47, + 670, + 134, + 681 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 670, + 134, + 681 + ], + "spans": [ + { + "bbox": [ + 47, + 670, + 134, + 681 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 689, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 286, + 713 + ], + "type": "text", + "content": "Change detection in remote sensing images has attracted much attention over the last years, resulting in numerous" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 72, + 545, + 311 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 311 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 311 + ], + "type": "text", + "content": "publications in this field [14, 15, 19, 2, 11, 12, 33, 18, 20]. Most state-of-the-art methods employ deep learning and introduce various sophisticated ways of merging bi-temporal image features. For instance, [7] proposes a series of fully convolutional architectures for change detection that rely on different fusion mechanisms for the bi-temporal image features. Furthermore, [12] uses NestedUNet [34] in combination with channel attention. With the introduction of transformer architectures into computer vision [10, 4, 29], recent architectures for change detection also utilize attention blocks. BiT [5] was the first of these methods, combining a CNN backbone with cross-attention layers in the decoder head. Subsequently, works like CDViT [22], ChangeFormer [2], FHD [19], and Changer [11] use the attention mechanism in various forms, pushing the state-of-the-art in bi-temporal change detection even further. Our general architecture is inspired by ChangeFormer and FHD, which adopt the MiT backbone and the MLP head from SegFormer [29] and add specialized mechanisms to fuse the bi-temporal image features." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 312, + 545, + 622 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 312, + 545, + 622 + ], + "spans": [ + { + "bbox": [ + 304, + 312, + 545, + 622 + ], + "type": "text", + "content": "LEVIR-CD [6], DSIFN-CD [31], WHU [13], and S2Looking [21] are common benchmark datasets for bi-temporal change detection, where networks are provided with co-registered, bi-temporal images as input and have to predict a pixelwise, binary change mask. Recently, a new dataset for change detection has been published with DynamicEarthNet [26], which surpasses previous datasets in terms of volume and diversity. In addition, models have to predict semantic segmentation masks containing the land cover classes next to the binary change masks for this dataset. However, none of these methods or datasets consider inputs other than bi- or multi-temporal images. Thus, previous approaches ignore the fact that pre-change semantic information for the area of interest is often available. For semantic segmentation on the other hand, it has been shown that semantic maps extracted from geographic information systems (GIS) can be effectively used to improve segmentation quality [1, 16]. In a change detection setting, only for the specific task of road network extraction [3] challenged the community to come up with solutions for updating road networks when pre-change road networks are given. Consequently, their approach considers graph data as input and output. In contrast, we consider the pixelwise change detection task when pre-change semantic information in the form of a pixelwise map is available and show that this paradigm opens up exciting new possibilities." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 633, + 474, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 633, + 474, + 647 + ], + "spans": [ + { + "bbox": [ + 306, + 633, + 474, + 647 + ], + "type": "text", + "content": "3. Conditional Change Detection" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": "We consider two points in time " + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "inline_equation", + "content": "t_1" + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": " (pre-change) and " + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "inline_equation", + "content": "t_2" + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": " (post-change). Correspondingly, we have two image versions " + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "inline_equation", + "content": "I^{(1)}" + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "inline_equation", + "content": "I^{(2)}" + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": " for the same geographic location at " + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "inline_equation", + "content": "t_1" + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "inline_equation", + "content": "t_2" + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": ", respectively. The ground-truth binary mask " + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "inline_equation", + "content": "b" + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": " indicates which pixels in the images have changed semanti" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16838" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 70, + 288, + 171 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 288, + 171 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 288, + 171 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 288, + 171 + ], + "type": "table", + "html": "
TaskInput I(1)I(2)m(1)Output b m(2)
Bi-temp. Bin. Change Det. (BCD)✓✓✓
Bi-temp. Sem. Change Det. (SCD)✓✓✓
[ new]Conditional BCD✓✓✓
[ new]Conditional SCD✓✓✓
[ new]Cross-modal BCD✓✓
[ new]Cross-modal SCD✓✓
", + "image_path": "efd761a5f26420abe3d7817f0a274122e9d9eca33fb8551894d6ce308a559f14.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 178, + 287, + 201 + ], + "lines": [ + { + "bbox": [ + 46, + 178, + 287, + 201 + ], + "spans": [ + { + "bbox": [ + 46, + 178, + 287, + 201 + ], + "type": "text", + "content": "Table 1: Inputs and outputs for different change detection tasks." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "spans": [ + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "text", + "content": "cally between " + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "inline_equation", + "content": "t_1" + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "inline_equation", + "content": "t_2" + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "text", + "content": ". Furthermore, we consider semantic maps " + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "inline_equation", + "content": "m^{(2)}" + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "text", + "content": " containing the semantic class " + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "inline_equation", + "content": "c \\in \\mathcal{C}" + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "text", + "content": " for each pixel in " + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "inline_equation", + "content": "I^{(1)}" + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "inline_equation", + "content": "I^{(2)}" + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "text", + "content": ", respectively. Thus, " + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "inline_equation", + "content": "b" + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "text", + "content": " can be obtained from " + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "inline_equation", + "content": "m^{(2)}" + }, + { + "bbox": [ + 46, + 223, + 287, + 319 + ], + "type": "text", + "content": " via a pixelwise inequality operation. As we propose new tasks in this paper (Conditional Change Detection and Cross-modal Change Detection), we provide a differentiated description of the existing and novel tasks here. An overview can be seen in Table 1." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "spans": [ + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "text", + "content": "Existing Tasks In general, change detection tasks differ in two aspects: input and output. We can distinguish w.r.t. the output between binary and semantic change detection (BCD and SCD) for every combination of inputs. In BCD, the goal is to predict the binary change mask " + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "inline_equation", + "content": "\\hat{b}" + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "text", + "content": ", indicating which pixels have changed semantically. SCD was recently proposed in [26] and constitutes an extension of BCD. Here, not only the binary change mask " + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "inline_equation", + "content": "\\hat{b}" + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "text", + "content": " is predicted, but also the semantic segmentation " + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(2)}" + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "text", + "content": " of the post-change image " + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "inline_equation", + "content": "I^{(2)}" + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "text", + "content": ". This allows us to tell which regions have changed and how they have changed. The corresponding evaluation metric " + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "inline_equation", + "content": "SCS" + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "text", + "content": " proposed in [26] combines the binary change IoU " + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "inline_equation", + "content": "BC" + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "text", + "content": " and the semantic change metric " + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "inline_equation", + "content": "SC" + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "text", + "content": " as their arithmetic mean. The semantic change metric " + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "inline_equation", + "content": "SC" + }, + { + "bbox": [ + 46, + 319, + 288, + 511 + ], + "type": "text", + "content": " is the standard mIoU from semantic segmentation, except that it is computed only on the pixels that have changed, i.e." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 50, + 518, + 284, + 549 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 50, + 518, + 284, + 549 + ], + "spans": [ + { + "bbox": [ + 50, + 518, + 284, + 549 + ], + "type": "interline_equation", + "content": "S C = \\frac {1}{| \\mathcal {C} |} \\sum_ {c \\in \\mathcal {C}} \\frac {| \\{b = 1 \\} \\cap \\{m ^ {(2)} = c \\} \\cap \\{\\hat {m} ^ {(2)} = c \\} |}{| \\{b = 1 \\} \\cap (\\{m ^ {(2)} = c \\} \\cup \\{\\hat {m} ^ {(2)} = c \\}) |},", + "image_path": "c4026f68fb0c475f34bcdd2494c0598abd41e0b6594afb6ab5a2ede7b8b2e6e4.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 51, + 552, + 287, + 574 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 552, + 287, + 574 + ], + "spans": [ + { + "bbox": [ + 51, + 552, + 287, + 574 + ], + "type": "interline_equation", + "content": "B C = I o U (b, \\hat {b}) \\quad \\text {a n d} \\quad S C S = \\frac {B C + S C}{2} \\tag {1}", + "image_path": "2a08638b0a22f8af3bb68b98f357507b1e1ec3003dc92dd25ba109e687bebc6b.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 582, + 287, + 617 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 287, + 617 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 287, + 617 + ], + "type": "text", + "content": "Regarding the input, the existing settings consider bi-temporal images " + }, + { + "bbox": [ + 46, + 582, + 287, + 617 + ], + "type": "inline_equation", + "content": "I^{(1)}" + }, + { + "bbox": [ + 46, + 582, + 287, + 617 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 582, + 287, + 617 + ], + "type": "inline_equation", + "content": "I^{(2)}" + }, + { + "bbox": [ + 46, + 582, + 287, + 617 + ], + "type": "text", + "content": ". Thus, we will refer to the existing tasks as bi-temporal BCD and bi-temporal SCD." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "type": "text", + "content": "Conditional Change Detection While the aforementioned change detection tasks assume bi-temporal images as input, semantic information in the form of a segmentation map " + }, + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "type": "text", + "content": " at " + }, + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "type": "inline_equation", + "content": "t_1" + }, + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "type": "text", + "content": " may be employed additionally. That is, given pre- and post-change images together with pre-change semantic information " + }, + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "type": "text", + "content": ", the goal is to predict the binary change mask " + }, + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\hat{b}" + }, + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "type": "text", + "content": " for Conditional BCD (as well as the semantic segmentation map " + }, + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(2)}" + }, + { + "bbox": [ + 46, + 618, + 288, + 714 + ], + "type": "text", + "content": " for Conditional SCD)." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 72, + 547, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 193 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 193 + ], + "type": "text", + "content": "Cross-modal Change Detection When pre-change semantic maps are available, change detection can also be conducted without bi-temporal, but solely uni-temporal imagery. In this case, only comparing the semantic information " + }, + { + "bbox": [ + 304, + 72, + 547, + 193 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 304, + 72, + 547, + 193 + ], + "type": "text", + "content": " and the current imagery " + }, + { + "bbox": [ + 304, + 72, + 547, + 193 + ], + "type": "inline_equation", + "content": "I^{(2)}" + }, + { + "bbox": [ + 304, + 72, + 547, + 193 + ], + "type": "text", + "content": " can suffice to detect semantic changes. In other words, this setting corresponds to Conditional Change Detection with uni-temporal images. We call this task Cross-modal Change Detection as the change has to be detected across different modalities (semantic pre-change map and post-change image)." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 204, + 385, + 217 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 204, + 385, + 217 + ], + "spans": [ + { + "bbox": [ + 305, + 204, + 385, + 217 + ], + "type": "text", + "content": "4. MapFormer" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 224, + 426, + 236 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 224, + 426, + 236 + ], + "spans": [ + { + "bbox": [ + 305, + 224, + 426, + 236 + ], + "type": "text", + "content": "4.1. Overall Architecture" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "spans": [ + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": "To handle these new tasks, we propose a framework, which is inspired by [19, 2] (see Figure 2). We feed the images " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "I^{(1)}" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "I^{(2)}" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": " through the same backbone to obtain multi-scale feature maps " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "f^{(1)}" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": ". For each scale, we have a separate fusion module (see Section 4.2) that handles the features from " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "f^{(1)}" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": " at the corresponding scale. In addition to the image features, in our setting, we also feed semantic information in the form of an encoded map " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": " into the fusion modules. These map features are obtained from " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": " via a shallow encoder (see Section 4.4). The outputs of the fusion modules are then multi-scale features " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": ", containing information of both points in time " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "t_1" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "t_2" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": ". Thus, we can use them in a prediction head to output the binary change map " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "\\hat{b}" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": ". In terms of architecture, this prediction head is a standard semantic segmentation head [29]. Furthermore, we apply a contrastive loss on the image features " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "f^{(1)}" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 304, + 243, + 546, + 458 + ], + "type": "text", + "content": ", which helps the model to learn semantically more meaningful representations (see Section 4.3)." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "spans": [ + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "text", + "content": "For many applications, it may be interesting to determine into which semantic class a pixel has changed. In this case, we also need to derive a semantic segmentation map " + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(2)}" + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "text", + "content": " for " + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "inline_equation", + "content": "I^{(2)}" + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "text", + "content": ". We can accomplish this either by feeding the unitemporal features " + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "text", + "content": " into a separate head for semantic segmentation or by predicting both " + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "inline_equation", + "content": "\\hat{b}" + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(2)}" + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "text", + "content": " based on the merged features " + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "text", + "content": ". We analyze both variants in Section 5.5. Training a semantic segmentation head on uni-temporal image features also allows applying the trained model without pre-change information as we can use the predicted semantic segmentation " + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(1)}" + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "text", + "content": " instead of " + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "text", + "content": ". Results for this setting are provided in Section 5.3. Furthermore, for Cross-modal Change Detection, the design of our fusion module (described next) enables us to omit the image features " + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "inline_equation", + "content": "f^{(1)}" + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "inline_equation", + "content": "I^{(1)}" + }, + { + "bbox": [ + 304, + 459, + 547, + 638 + ], + "type": "text", + "content": ". We evaluate this setting in Section 5.4." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 647, + 462, + 658 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 647, + 462, + 658 + ], + "spans": [ + { + "bbox": [ + 305, + 647, + 462, + 658 + ], + "type": "text", + "content": "4.2. Multi-modal Feature Fusion" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "type": "text", + "content": "The main challenge in bi-temporal change detection is to design an effective method for fusing the bi-temporal image features. In the case of Conditional (and Cross-modal) Change Detection, we additionally have to bring together" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "16839" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 85, + 70, + 523, + 238 + ], + "blocks": [ + { + "bbox": [ + 85, + 70, + 523, + 238 + ], + "lines": [ + { + "bbox": [ + 85, + 70, + 523, + 238 + ], + "spans": [ + { + "bbox": [ + 85, + 70, + 523, + 238 + ], + "type": "image", + "image_path": "074a10110bb3b7794f64e422b247497d9e12c3d442a445a87c2155037dfc802f.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 248, + 547, + 276 + ], + "lines": [ + { + "bbox": [ + 46, + 248, + 547, + 276 + ], + "spans": [ + { + "bbox": [ + 46, + 248, + 547, + 276 + ], + "type": "text", + "content": "Figure 2: The proposed MapFormer framework consists of two main components: a novel fusion module, which combines inputs from different points in time and modalities, and a contrastive loss module, which is only used during training." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 48, + 296, + 279, + 388 + ], + "blocks": [ + { + "bbox": [ + 48, + 296, + 279, + 388 + ], + "lines": [ + { + "bbox": [ + 48, + 296, + 279, + 388 + ], + "spans": [ + { + "bbox": [ + 48, + 296, + 279, + 388 + ], + "type": "image", + "image_path": "c49cdb411da3fc8dd0179dade9c79825fee0ef4c769bec92907a13aa3867c444.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 396, + 288, + 422 + ], + "lines": [ + { + "bbox": [ + 46, + 396, + 288, + 422 + ], + "spans": [ + { + "bbox": [ + 46, + 396, + 288, + 422 + ], + "type": "text", + "content": "Figure 3: Our multi-modal feature fusion module for fusing bi-temporal image features and semantic input features." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 447, + 287, + 520 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 447, + 287, + 520 + ], + "spans": [ + { + "bbox": [ + 46, + 447, + 287, + 520 + ], + "type": "text", + "content": "different modalities, i.e., the image features and the available semantic information. To this end, we propose a novel multi-modal feature fusion module. Subsequently, we follow [19, 29] and assume that the spatial context is encoded within the backbone, so we only consider pointwise operations, treating each spatial location separately." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 522, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 522, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 522, + 288, + 715 + ], + "type": "text", + "content": "A standard way of merging multi-modal features is a simple concatenation along the channel dimension. However, we argue that the semantic information in our setting can be used more effectively if we use it to modulate the features dynamically. Thus, the given information should influence the processing of image features and thereby improve perception. Such data-dependent feature processing can be achieved by dynamically predicting the weights of one or more layers from the features themselves [30, 25]. While such techniques are powerful, they come at a significant computational cost. In fact, applying a method like DynamicMLP [30] to a segmentation task like ours by predicting dynamic weights for each pixel separately is intractable without drastically reducing the number of channels (or the spatial resolution). Therefore, we resort to a restricted attention-style approach. More precisely, to keep" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 293, + 545, + 329 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 293, + 545, + 329 + ], + "spans": [ + { + "bbox": [ + 304, + 293, + 545, + 329 + ], + "type": "text", + "content": "the computational cost tractable, we restrict the attention to a set of " + }, + { + "bbox": [ + 304, + 293, + 545, + 329 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 304, + 293, + 545, + 329 + ], + "type": "text", + "content": " values for each output dimension, thereby greatly reducing the complexity compared to unrestricted attention." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "spans": [ + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": "A visualization of our proposed multi-modal feature fusion module can be seen in Figure 3. First, we concatenate the bi-temporal features " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "f_{(i,j)}^{(1)}" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "f_{(i,j)}^{(2)}" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " and the map feature " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "g_{(i,j)}^{(1)}" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " for each spatial location " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "(i,j)" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": ". This concatenated feature is fed through " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " separate MLPs (implemented with grouped, pointwise convolutions) to obtain " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " joint representations " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "(h_{k(i,j)})_{k=1\\dots K}" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "D_f" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " channels. Here, " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "D_f" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " refers to the dimensionality of " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "f_{(i,j)}^{(t)}, t = 1,2" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " is a hyperparameter for tuning the semantic variety. These " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " joint representations " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "(h_{k(i,j)})_{k=1\\dots K}" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " can be interpreted as views, encoding different aspects of the same spatial location. To associate the map information " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "g_{(i,j)}^{(1)}" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " with these views, we employ a channelwise attention mechanism. In particular, we compute attention weights by feeding the map features " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "g_{(i,j)}^{(1)}" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " into an additional MLP. The result of shape " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "K\\times D_f" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " is softmaxed over the " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": "-dimension providing a matrix of attention scores with entries " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "a_{(i,j,k,d)}" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " for location " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "(i,j)" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": ". Thus, each channel of the module output " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "f_{(i,j)}" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " separately attends to the " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": " joint representations " + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "inline_equation", + "content": "(h_{k(i,j)})_{k=1\\dots K}" + }, + { + "bbox": [ + 304, + 330, + 546, + 582 + ], + "type": "text", + "content": ". In mathematical terms, we compute" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 334, + 587, + 545, + 624 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 334, + 587, + 545, + 624 + ], + "spans": [ + { + "bbox": [ + 334, + 587, + 545, + 624 + ], + "type": "interline_equation", + "content": "f _ {(i, j)} = \\left(\\sum_ {k = 1 \\dots K} a _ {(i, j, k, d)} h _ {k (i, j, d)}\\right) _ {d = 1 \\dots D _ {f}} \\tag {2}", + "image_path": "c0f26f737d0e860c0b0d08620894db004d6ddbc4844fc37dc1e9b0f09bdce82c.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 628, + 545, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 628, + 545, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 628, + 545, + 665 + ], + "type": "text", + "content": "The merged features " + }, + { + "bbox": [ + 304, + 628, + 545, + 665 + ], + "type": "inline_equation", + "content": "f_{(i,j)}" + }, + { + "bbox": [ + 304, + 628, + 545, + 665 + ], + "type": "text", + "content": " are then collected for the different scales of the backbone feature maps and passed to the prediction head." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 671, + 408, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 671, + 408, + 682 + ], + "spans": [ + { + "bbox": [ + 306, + 671, + 408, + 682 + ], + "type": "text", + "content": "4.3. Contrastive Loss" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "text", + "content": "For unchanged areas, we want " + }, + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "inline_equation", + "content": "f^{(1)}, f^{(2)}" + }, + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 304, + 689, + 545, + 714 + ], + "type": "text", + "content": " to encode the same semantic concepts. For changed areas how-" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "16840" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "text", + "content": "ever, the encoded information in " + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "inline_equation", + "content": "f^{(1)}" + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "text", + "content": " should be similar, while " + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "text", + "content": " should be dissimilar from the two. Based on this observation, we design a supervised contrastive loss that forces the network to learn better image features. More precisely, we apply a learnable projection " + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "inline_equation", + "content": "\\pi" + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "text", + "content": " to map " + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "inline_equation", + "content": "f^{(1)}" + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "text", + "content": " into the feature space of " + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 46, + 71, + 289, + 156 + ], + "type": "text", + "content": ". Then, we compute our contrastive loss as follows:" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 158, + 289, + 218 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 158, + 289, + 218 + ], + "spans": [ + { + "bbox": [ + 47, + 158, + 289, + 218 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {L} _ {(i, j)} ^ {(c o n t r)} = - \\operatorname {s i m} \\left(g _ {(i, j)} ^ {(1)}, \\pi \\left(f _ {(i, j)} ^ {(1)}\\right)\\right) \\tag {3} \\\\ + \\left\\{ \\begin{array}{l l} - \\operatorname {s i m} \\left(g _ {(i, j)} ^ {(1)}, \\pi \\big (f _ {(i, j)} ^ {(2)} \\big)\\right), & b _ {(i, j)} = 0 \\\\ \\max \\left(\\operatorname {s i m} \\left(g _ {(i, j)} ^ {(1)}, \\pi \\big (f _ {(i, j)} ^ {(2)} \\big)\\right), 0\\right), & b _ {(i, j)} = 1. \\end{array} \\right. \\\\ \\end{array}", + "image_path": "d081fc4f3dae5f6ca29886145eb14591a3352c03bc10e98db43d21d61158cc8b.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 221, + 288, + 293 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 221, + 288, + 293 + ], + "spans": [ + { + "bbox": [ + 46, + 221, + 288, + 293 + ], + "type": "text", + "content": "Here, " + }, + { + "bbox": [ + 46, + 221, + 288, + 293 + ], + "type": "inline_equation", + "content": "\\operatorname{sim}(\\cdot, \\cdot)" + }, + { + "bbox": [ + 46, + 221, + 288, + 293 + ], + "type": "text", + "content": " denotes the cosine similarity, and the loss is ultimately aggregated over all pixel locations " + }, + { + "bbox": [ + 46, + 221, + 288, + 293 + ], + "type": "inline_equation", + "content": "(i,j)" + }, + { + "bbox": [ + 46, + 221, + 288, + 293 + ], + "type": "text", + "content": ". Interestingly, we found it beneficial not to use a projection for " + }, + { + "bbox": [ + 46, + 221, + 288, + 293 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 46, + 221, + 288, + 293 + ], + "type": "text", + "content": " and also not to backpropagate gradients coming from the contrastive loss through " + }, + { + "bbox": [ + 46, + 221, + 288, + 293 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 46, + 221, + 288, + 293 + ], + "type": "text", + "content": ". Details can be found in Section 5.3." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 299, + 164, + 311 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 299, + 164, + 311 + ], + "spans": [ + { + "bbox": [ + 47, + 299, + 164, + 311 + ], + "type": "text", + "content": "4.4. Architecture Details" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "spans": [ + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "text", + "content": "Like [19], we use the MixVisionTransformer from [29] as image encoder backbone. Due to the spatial attention in the encoder, the features " + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "inline_equation", + "content": "f_{(i,j)}^{(t)}" + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "text", + "content": " are already contextualized, and a pointwise prediction head after a pointwise fusion module suffices to produce high-quality predictions. We leave SegFormer's prediction head unchanged and solely plug in our proposed feature fusion module between the backbone and the head. Thus, our module can be easily combined with other architectures. Inside our feature fusion module, the merged features " + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "inline_equation", + "content": "(h_k)_{k=1\\dots K}" + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "text", + "content": " are produced by " + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "text", + "content": " two-layer MLPs, while the attention weights " + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "inline_equation", + "content": "a" + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "text", + "content": " are predicted from " + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "text", + "content": " via a linear layer. To encode the semantic information " + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "text", + "content": " into " + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "text", + "content": ", we use a three-layer CNN with a pointwise convolution followed by two convolutions with a kernel size of five and a dilation of two to increase the receptive field. When fusing the encoded map " + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "text", + "content": ", we use bilinear interpolation to comply with the different spatial resolutions of the different scales of the image feature maps. The projection head " + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "inline_equation", + "content": "\\pi" + }, + { + "bbox": [ + 46, + 317, + 289, + 594 + ], + "type": "text", + "content": " for the contrastive loss is a pointwise MLP head in the style of SegFormer's prediction head. The overall training loss is the sum of our contrastive loss and the cross-entropy loss for the binary change map (as well as the semantic segmentation in SCD)." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 604, + 128, + 617 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 604, + 128, + 617 + ], + "spans": [ + { + "bbox": [ + 47, + 604, + 128, + 617 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 623, + 110, + 635 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 623, + 110, + 635 + ], + "spans": [ + { + "bbox": [ + 47, + 623, + 110, + 635 + ], + "type": "text", + "content": "5.1. Datasets" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "text", + "content": "Since Conditional Change Detection requires semantic segmentation maps, which are not included in commonly used benchmark datasets such as LEVIR-CD [6], DSIFN-CD [31], and S2Looking [21], we conduct our experiments on DynamicEarthNet [26] and HRSCD [8]. DynamicEarthNet is a recent dataset consisting of daily images of 75 areas" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 72, + 545, + 216 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 216 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 216 + ], + "type": "text", + "content": "of interest (AOIs) over a span of two years. Ground-truth annotations containing the seven land use classes \"impervious surface\", \"agriculture\", \"forest & other vegetation\", \"wetlands\", \"soil\", \"water\", and \"snow & ice\" are only available for the first day of each month and 55 AOIs. As our setting assumes semantic information as input, we only use the images with available annotations and selected 35, 10, and 10 AOIs for training, validation, and testing, respectively. Following [26], we omit the class \"snow & ice\" from the evaluation because it only occurs in two AOIs. Targets for binary change detection were created by applying a pixelwise inequality on pairs of ground-truth semantic maps." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 217, + 545, + 337 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 217, + 545, + 337 + ], + "spans": [ + { + "bbox": [ + 304, + 217, + 545, + 337 + ], + "type": "text", + "content": "The High-Resolution Semantic Change Detection (HRSCD) dataset was proposed in [8]. It contains 291 pairs of images, where the first was acquired in 2005/2006 and the second in 2012. Semantic ground-truth segmentation maps and binary change segmentation maps are available for all samples. The semantic classes are \"artificial surface\", \"agricultural area\", \"forest\", \"wetland\", and \"water\". We selected 191, 50, and 50 pairs for training, validation, and testing, respectively. Further details on both datasets can be found in the supplementary material." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 347, + 372, + 358 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 347, + 372, + 358 + ], + "spans": [ + { + "bbox": [ + 306, + 347, + 372, + 358 + ], + "type": "text", + "content": "5.2. Baselines" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "content": "As baselines derived from semantic segmentation models, we employ SegFormer [29], Swin + UPerNet [17, 28], and SETR-PUP [32] for change detection by taking the pixelwise inequality of the predicted semantic segmentations " + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(1)}" + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(2)}" + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "content": " as binary change prediction. The concatenation baseline for bi-temporal BCD resembles the SegFormer architecture, but concatenates the image features " + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "inline_equation", + "content": "f^{(1)}" + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "content": " before passing them to a head that directly predicts the binary change map. These baselines can be easily reused for Conditional BCD. For the semantic segmentation baselines, we apply the pixelwise inequality to " + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(2)}" + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "content": " instead of " + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(1)}" + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(2)}" + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "content": ". For the concatenation baseline, we concatenate map features " + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "content": " extracted by a map encoder as described in Section 4.4 to the image features " + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "inline_equation", + "content": "f^{(1)}" + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 304, + 366, + 545, + 713 + ], + "type": "text", + "content": ". As state-of-the-art methods for bi-temporal BCD, we select FHD [19], ChangerEx [11], and ChangeFormer [2] as they are recent and have been shown to perform best on the common benchmarks. We also extend these methods for Conditional BCD by concatenating map features to merged bi-temporal image features. Further, we consider another baseline for Conditional BCD, which has a separate concatenation-based BCD head for every semantic class such that the final change prediction can be taken from the head corresponding to the pre-change semantic class for every pixel. To have a strong competitor for our feature fusion module, we also use a pixel-wise Dynamic MLP-C [30] for fusing semantic input with image features. For training details as well as a comparison of model sizes, we refer to the supplementary material." + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16841" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 70, + 287, + 439 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 287, + 439 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 287, + 439 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 287, + 439 + ], + "type": "table", + "html": "
MethodDynENetHRSCD
F1IoUF1IoU
Bi-temporal BCD:
SegFormer [29]20.311.317.89.7
Swin + UPerNet [17, 28]20.111.117.69.7
SETR-PUP [32]19.410.814.88.0
Concatenation20.711.641.225.9
FHD [19]17.29.445.229.2
ChangerEx [11]21.111.837.022.7
ChangeFormer [2]20.711.545.729.6
MapFormerK=10 (w/o m(1))28.616.743.928.2
Conditional BCD:
SegFormer [29]21.211.95.62.8
Swin + UPerNet [17, 28]21.812.25.62.8
SETR-PUP [32]20.811.65.42.8
Concatenation33.520.162.145.1
FHD [19] + Concat.33.219.961.244.1
ChangerEx [11] + Concat.30.918.358.141.0
ChangeFormer [2] + Concat.31.418.661.544.4
Classwise CD-Heads37.022.762.345.3
DynamicMLP [30]34.520.862.745.7
MapFormerK=534.821.164.948.0
MapFormerK=1038.023.564.547.7
MapFormerK=1536.422.264.547.6
Ablations (MapFormerK=10):
w/o constrastive34.520.963.846.8
w/o stop-gradient36.722.562.545.4
w/ map proj.35.821.860.745.9
high-level info29.817.664.447.5
low-res. info30.417.960.343.2
", + "image_path": "6921e73ea79b31815e685e6221a48709c8228484b353c639b378c185c6583b28.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 447, + 287, + 485 + ], + "lines": [ + { + "bbox": [ + 46, + 447, + 287, + 485 + ], + "spans": [ + { + "bbox": [ + 46, + 447, + 287, + 485 + ], + "type": "text", + "content": "Table 2: (Conditional) Binary Change Detection as well as ablations. Our method performs best and is still highly competitive without ground-truth semantic input." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 47, + 511, + 188, + 525 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 511, + 188, + 525 + ], + "spans": [ + { + "bbox": [ + 47, + 511, + 188, + 525 + ], + "type": "text", + "content": "5.3. Binary Change Detection" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 533, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 533, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 533, + 288, + 715 + ], + "type": "text", + "content": "Overall Performance In BCD, there is only a single objective (binary change IoU); thus, our approach can be best compared to other methods. In Table 2, we present BCD results for baselines, state-of-the-art methods, and our method. It is evident that Conditional BCD greatly outperforms all existing bi-temporal methods - even with the simple concatenation baseline (11.8% vs. 20.1% and 29.6% vs. 45.1% IoU, resp.). MapFormer further pushes the performance on both datasets to 23.5% and 48.0% IoU, respectively. Particularly, our method also outperforms DynamicMLP [30], a state-of-the-art method for multi-modal feature fusion. This holds for all tested values of our only hyperparameter " + }, + { + "bbox": [ + 46, + 533, + 288, + 715 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 46, + 533, + 288, + 715 + ], + "type": "text", + "content": " and even without our contrastive loss (see Ablations). Remarkably, when MapFormer is applied without the true map " + }, + { + "bbox": [ + 46, + 533, + 288, + 715 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 46, + 533, + 288, + 715 + ], + "type": "text", + "content": ", but only predicted segmentation" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "spans": [ + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "type": "text", + "content": "maps " + }, + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(1)}" + }, + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "type": "text", + "content": " (" + }, + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "type": "inline_equation", + "content": "w / o m^{(1)}" + }, + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "type": "text", + "content": "), the performance is still highly competitive, even achieving by far the best performance among the bi-temporal methods on DynamicEarthNet with an IoU of " + }, + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "type": "inline_equation", + "content": "16.7\\%" + }, + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "type": "text", + "content": ". Furthermore, it is noteworthy that the semantic segmentation baselines SegFormer, Swin + UPerNet and SETR perform poorly in Conditional BCD, especially on HRSCD. We attribute this to the fact that every misclassified pixel leads to a false positive change prediction in this setup, causing a very low precision. In bi-temporal BCD, identical classification errors in " + }, + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(1)}" + }, + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(2)}" + }, + { + "bbox": [ + 304, + 71, + 547, + 205 + ], + "type": "text", + "content": " may still lead to true negative change predictions." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "spans": [ + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "text", + "content": "Ablations In the lower part of Table 2, we present several ablation experiments to analyze MapFormer's contributing factors and robustness. First, we study the effect of our design choices in the contrastive loss module. When the contrastive loss is completely omitted (w/o contrastive), performance drops on both datasets by " + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "inline_equation", + "content": "2.6\\%" + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "inline_equation", + "content": "0.9\\%" + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "text", + "content": " IoU, respectively. Furthermore, we compare MapFormer with modifications where we omitted the stop-gradient operation on the map features " + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "text", + "content": " (w/o stop-gradient) and a version where we included a linear projection layer to map " + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "text", + "content": " to the joint embedding space with " + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "inline_equation", + "content": "\\pi \\left(f^{(t)}\\right)" + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "text", + "content": " (w/ map proj.). Both variants do not reach the performance of our proposed method. Thus, we conclude that gradients coming from the contrastive loss flowing through the map features " + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "inline_equation", + "content": "g^{(1)}" + }, + { + "bbox": [ + 304, + 219, + 547, + 400 + ], + "type": "text", + "content": " have a detrimental effect on their representation." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 415, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 415, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 415, + 547, + 715 + ], + "type": "text", + "content": "Finally, we investigate the effect of the quality of the semantic information " + }, + { + "bbox": [ + 304, + 415, + 547, + 715 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 304, + 415, + 547, + 715 + ], + "type": "text", + "content": ". To this end, we merge some classes in the pre-change maps to simulate that only high-level semantic information is available (high-level info). For DynamicEarthNet, we merge the classes \"agriculture\", \"forest & other vegetation\" and \"soil\" as well as \"wetlands\", \"water\" and \"snow & ice\" into two high-level classes, respectively. For HRSCD, we solely distinguish between \"artificial\" and \"rest\". Apparently, this high-level information still suffices to generate better change predictions than the bi-temporal change detection methods. However, we observe a significant performance drop on DynamicEarthNet (5.9% IoU), while the performance only degrades marginally on HRSCD (0.2% IoU). Furthermore, we simulate low-resolution semantic information by downsampling with a factor of 32 (low-res. info). Here, we can see that the performance of our method degrades with the low-resolution input (by 5.6% and 4.8% IoU, resp.). Nevertheless, it is still clearly superior to the bi-temporal change detection methods. In conclusion, our results show that the semantic input quality correlates to the Conditional Change Detection performance. However, low-quality input still suffices to achieve significantly better results than methods not relying on this kind of information. Further ablations can be found in the supplementary material." + } + ] + } + ], + "index": 6 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "16842" + } + ] + } + ], + "index": 7 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 70, + 216, + 159 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 216, + 159 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 216, + 159 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 216, + 159 + ], + "type": "table", + "html": "
MethodDynENetHRSCD
F1IoUF1IoU
SegFormer21.211.95.62.8
Swin+UPerNet21.812.25.62.8
SETR-PUP20.811.65.42.8
Concatenation31.818.961.544.4
MapFormer32.019.062.145.0
", + "image_path": "dfc982cb6bd2e300e3490025c0208595d212f4d590ecde0f5edfdc2a0ca1ce58.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 223, + 70, + 545, + 169 + ], + "blocks": [ + { + "bbox": [ + 223, + 70, + 545, + 169 + ], + "lines": [ + { + "bbox": [ + 223, + 70, + 545, + 169 + ], + "spans": [ + { + "bbox": [ + 223, + 70, + 545, + 169 + ], + "type": "table", + "html": "
MethodDynamicEarthNetHRSCD
BCSCSCSmIoUBCSCSCSmIoU
SegFormer11.331.521.439.79.720.315.052.7
Swin + UperNet11.128.019.641.49.720.915.353.1
SETR-PUP10.826.318.538.58.521.714.950.5
MapFormer (sem. seg. on f(2))23.029.026.039.948.021.534.752.9
MapFormer (sem. seg. on f)23.113.118.161.548.212.530.472.3
MapFormer (Cross-modal)20.430.725.540.345.621.733.549.9
", + "image_path": "40b678ad7c98b01f22cecfb240e4470b58bfa450c2d4ea18b6d93e1f189ef5e1.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 166, + 218, + 202 + ], + "lines": [ + { + "bbox": [ + 47, + 166, + 218, + 202 + ], + "spans": [ + { + "bbox": [ + 47, + 166, + 218, + 202 + ], + "type": "text", + "content": "Table 3: Cross-modal Binary Change Detection. MapFormer and the concatenation baseline outperform SegFormer." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 220, + 178, + 545, + 202 + ], + "lines": [ + { + "bbox": [ + 220, + 178, + 545, + 202 + ], + "spans": [ + { + "bbox": [ + 220, + 178, + 545, + 202 + ], + "type": "text", + "content": "Table 4: (Conditional) Semantic Change Detection. Predicting " + }, + { + "bbox": [ + 220, + 178, + 545, + 202 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(2)}" + }, + { + "bbox": [ + 220, + 178, + 545, + 202 + ], + "type": "text", + "content": " based on " + }, + { + "bbox": [ + 220, + 178, + 545, + 202 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 220, + 178, + 545, + 202 + ], + "type": "text", + "content": " yields the best results w.r.t. the main objective SCS." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 47, + 223, + 251, + 236 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 223, + 251, + 236 + ], + "spans": [ + { + "bbox": [ + 47, + 223, + 251, + 236 + ], + "type": "text", + "content": "5.4. Cross-modal Binary Change Detection" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 242, + 288, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 242, + 288, + 434 + ], + "spans": [ + { + "bbox": [ + 46, + 242, + 288, + 434 + ], + "type": "text", + "content": "We also evaluate MapFormer on the task of Cross-modal BCD, i.e. change detection when only post-change imagery and pre-change map information are given (see Table 3). Here, the concatenation baseline omits the pre-change image features " + }, + { + "bbox": [ + 46, + 242, + 288, + 434 + ], + "type": "inline_equation", + "content": "f^{(1)}" + }, + { + "bbox": [ + 46, + 242, + 288, + 434 + ], + "type": "text", + "content": ". The semantic segmentation baselines are identical to the ones for Conditional BCD in Table 2 as they do not utilize " + }, + { + "bbox": [ + 46, + 242, + 288, + 434 + ], + "type": "inline_equation", + "content": "\\hat{m}^{(1)}" + }, + { + "bbox": [ + 46, + 242, + 288, + 434 + ], + "type": "text", + "content": ". Again, we can see that MapFormer performs best, although the margin to the concatenation baseline is rather small (0.1% and 0.6% IoU, resp.). However, comparing the results with those in Table 2, we observe that bi-temporal methods are greatly outperformed in this setting as well, and the performance is still relatively close to Conditional BCD, which relies on bi-temporal images. This highlights the value of semantic input for change detection and shows that bi-temporal images are not critical for change detection when pre-change maps are available." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 443, + 200, + 455 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 443, + 200, + 455 + ], + "spans": [ + { + "bbox": [ + 47, + 443, + 200, + 455 + ], + "type": "text", + "content": "5.5. Semantic Change Detection" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "text", + "content": "For semantic change detection, one can integrate additional semantic segmentation heads into our framework. We provide the results for Conditional SCD and Cross-modal SCD in Table 4. Here, we follow the notation of [26] and denote the binary change IoU with BC (instead of IoU in Tables 2,3). In the first three rows of Table 4, we reuse the semantic segmentation baselines of Table 2. The fourth and fifth rows correspond to MapFormer, with the semantic segmentation outputs being predicted from the uni-temporal image features (sem. seg. on " + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "text", + "content": ") and the merged features (sem. seg. on " + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "text", + "content": "), respectively. Apparently, the version with a segmentation head applied on " + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "text", + "content": " performs better w.r.t. BC, SC, and SCS, whereas the joint version is superior w.r.t. mIoU. Our reasoning is that the imbalance between changed and unchanged areas in the data causes the model using " + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "text", + "content": " to tend to repeat the given semantic information, which is not accessible through " + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "text", + "content": ". This hurts the performance on changed pixels (SC), but leads to higher overall mIoU. In the last row of Table 4, we show the results for MapFormer solely based on uni-temporal images (Cross-modal), using " + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "inline_equation", + "content": "f^{(2)}" + }, + { + "bbox": [ + 46, + 462, + 288, + 714 + ], + "type": "text", + "content": " for semantic segmentation. Sim" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 224, + 545, + 272 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 224, + 545, + 272 + ], + "spans": [ + { + "bbox": [ + 304, + 224, + 545, + 272 + ], + "type": "text", + "content": "ilar to our observations for BCD, this model is competitive to its counterpart for Conditional SCD (25.5% vs. 26.0% and 33.5% vs. 34.7% SCS, resp.). This implies that " + }, + { + "bbox": [ + 304, + 224, + 545, + 272 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 304, + 224, + 545, + 272 + ], + "type": "text", + "content": " has a stronger impact on the performance than " + }, + { + "bbox": [ + 304, + 224, + 545, + 272 + ], + "type": "inline_equation", + "content": "I^{(1)}" + }, + { + "bbox": [ + 304, + 224, + 545, + 272 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 296, + 418, + 308 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 296, + 418, + 308 + ], + "spans": [ + { + "bbox": [ + 306, + 296, + 418, + 308 + ], + "type": "text", + "content": "5.6. Qualitative Results" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 319, + 545, + 416 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 319, + 545, + 416 + ], + "spans": [ + { + "bbox": [ + 304, + 319, + 545, + 416 + ], + "type": "text", + "content": "The first row of Figure 4 (a) depicts inputs and ground-truth targets for a sample of DynamicEarthNet. The second row shows the binary change predictions of several methods for this sample. We can see that SegFormer suffers from many false positive predictions, while the other state-of-the-art methods struggle to detect the changed areas. In contrast, MapFormer produces a convincing change mask where only small details are missing." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "spans": [ + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "text", + "content": "In Figure 4 (b), we visualize the attention weights of MapFormer for this sample. The visualizations correspond to the argmax over the " + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "text", + "content": "-dimension of the attention weights " + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "inline_equation", + "content": "a_{(\\cdot ,\\cdot ,k,d)}" + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "text", + "content": " for six different channels " + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "text", + "content": ". In other words, the colors in each visualization show which of the features " + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "inline_equation", + "content": "(h_k)_{k = 1\\dots K}" + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "text", + "content": " receive most attention for the selected channels. Comparing them, we can see that the maps focus on different aspects of the semantic information " + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "inline_equation", + "content": "m_{1}" + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "text", + "content": ". For example, the first attention map mostly resembles the original map " + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "inline_equation", + "content": "m^{(1)}" + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "text", + "content": ", whereas the second and third visualizations resemble more coarse versions of " + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "inline_equation", + "content": "m_{1}" + }, + { + "bbox": [ + 304, + 421, + 545, + 589 + ], + "type": "text", + "content": ". On the other hand, the fourth map focuses more on small and thin segments such as roads. The remaining two attention maps seem to aim at separating the features for specific semantic classes." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "type": "text", + "content": "To provide further insight, we compare t-SNE [27] visualizations of the hidden features of MapFormer and FHD in Figure 4 (c). Each point in the visualization represents the hidden feature for one pixel in the sample depicted in subfigure (a). For MapFormer, the feature space is much less entangled, and the semantic classes of the pixels and the binary change ground truth can be separated from other pixels relatively well. In contrast, the FHD representations for different semantic and binary change classes are highly mixed, leading to prediction errors." + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16843" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 75, + 74, + 517, + 287 + ], + "blocks": [ + { + "bbox": [ + 75, + 74, + 517, + 287 + ], + "lines": [ + { + "bbox": [ + 75, + 74, + 517, + 287 + ], + "spans": [ + { + "bbox": [ + 75, + 74, + 517, + 287 + ], + "type": "image", + "image_path": "965499b0b5853f4d37485dbc7f6d85670cdccce1f7a1cdb0afdd1570476e1e13.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 204, + 290, + 389, + 301 + ], + "lines": [ + { + "bbox": [ + 204, + 290, + 389, + 301 + ], + "spans": [ + { + "bbox": [ + 204, + 290, + 389, + 301 + ], + "type": "text", + "content": "(a) Binary change prediction for different methods." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 77, + 304, + 515, + 380 + ], + "blocks": [ + { + "bbox": [ + 77, + 304, + 515, + 380 + ], + "lines": [ + { + "bbox": [ + 77, + 304, + 515, + 380 + ], + "spans": [ + { + "bbox": [ + 77, + 304, + 515, + 380 + ], + "type": "image", + "image_path": "f215da9a06252f105cb9e52c661bb414e15bfb7ae7fcbd70f204f2010b59bc09.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 66, + 386, + 526, + 409 + ], + "lines": [ + { + "bbox": [ + 66, + 386, + 526, + 409 + ], + "spans": [ + { + "bbox": [ + 66, + 386, + 526, + 409 + ], + "type": "text", + "content": "(b) Visualization of attentions weights. Colors encode which of the representations " + }, + { + "bbox": [ + 66, + 386, + 526, + 409 + ], + "type": "inline_equation", + "content": "(h_k)_{k = 1\\dots K}" + }, + { + "bbox": [ + 66, + 386, + 526, + 409 + ], + "type": "text", + "content": " received most attention for six selected channels " + }, + { + "bbox": [ + 66, + 386, + 526, + 409 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 66, + 386, + 526, + 409 + ], + "type": "text", + "content": ", exhibiting a focus on different aspects of the features for different " + }, + { + "bbox": [ + 66, + 386, + 526, + 409 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 66, + 386, + 526, + 409 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 66, + 386, + 526, + 409 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 66, + 386, + 526, + 409 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 85, + 413, + 165, + 489 + ], + "blocks": [ + { + "bbox": [ + 85, + 413, + 165, + 489 + ], + "lines": [ + { + "bbox": [ + 85, + 413, + 165, + 489 + ], + "spans": [ + { + "bbox": [ + 85, + 413, + 165, + 489 + ], + "type": "image", + "image_path": "9e7969a859e4c0f6a7d292f789443c3a71f8b5c83e03d4eda5b3fb343c5a6578.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 78, + 498, + 170, + 509 + ], + "lines": [ + { + "bbox": [ + 78, + 498, + 170, + 509 + ], + "spans": [ + { + "bbox": [ + 78, + 498, + 170, + 509 + ], + "type": "text", + "content": "(c.1) FHD [sem. classes]" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 200, + 413, + 279, + 489 + ], + "blocks": [ + { + "bbox": [ + 200, + 413, + 279, + 489 + ], + "lines": [ + { + "bbox": [ + 200, + 413, + 279, + 489 + ], + "spans": [ + { + "bbox": [ + 200, + 413, + 279, + 489 + ], + "type": "image", + "image_path": "41cfe88567adb453994f51abce1fe291fd594f3cb352c35e15e0a7ea3cc07ac3.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 195, + 498, + 283, + 509 + ], + "lines": [ + { + "bbox": [ + 195, + 498, + 283, + 509 + ], + "spans": [ + { + "bbox": [ + 195, + 498, + 283, + 509 + ], + "type": "text", + "content": "(c.2) FHD [bin. change]" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 315, + 413, + 394, + 490 + ], + "blocks": [ + { + "bbox": [ + 315, + 413, + 394, + 490 + ], + "lines": [ + { + "bbox": [ + 315, + 413, + 394, + 490 + ], + "spans": [ + { + "bbox": [ + 315, + 413, + 394, + 490 + ], + "type": "image", + "image_path": "e204a0bb457111d50ea4db0e365d630094409670f240db1abe0b506bd29a8dea.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 296, + 498, + 526, + 510 + ], + "lines": [ + { + "bbox": [ + 296, + 498, + 526, + 510 + ], + "spans": [ + { + "bbox": [ + 296, + 498, + 526, + 510 + ], + "type": "text", + "content": "(c.3) MapFormer [sem. classes] (c.4) MapFormer [bin. change]" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 51, + 514, + 541, + 537 + ], + "lines": [ + { + "bbox": [ + 51, + 514, + 541, + 537 + ], + "spans": [ + { + "bbox": [ + 51, + 514, + 541, + 537 + ], + "type": "text", + "content": "(c) t-SNE [27] visualizations of hidden features of FHD and our model. In the plots (c.1) and (c.3), colors correspond to the semantic classes of " + }, + { + "bbox": [ + 51, + 514, + 541, + 537 + ], + "type": "inline_equation", + "content": "m1" + }, + { + "bbox": [ + 51, + 514, + 541, + 537 + ], + "type": "text", + "content": ", whereas in (c.2) and (c.4), colors encode the binary change ground truth " + }, + { + "bbox": [ + 51, + 514, + 541, + 537 + ], + "type": "inline_equation", + "content": "b" + }, + { + "bbox": [ + 51, + 514, + 541, + 537 + ], + "type": "text", + "content": " (change, no change)." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 430, + 413, + 508, + 489 + ], + "blocks": [ + { + "bbox": [ + 430, + 413, + 508, + 489 + ], + "lines": [ + { + "bbox": [ + 430, + 413, + 508, + 489 + ], + "spans": [ + { + "bbox": [ + 430, + 413, + 508, + 489 + ], + "type": "image", + "image_path": "efff98210e2b4190a39c6e3f1f7963755cf9f4a1b9791b847df15afec3e40c5e.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 143, + 546, + 449, + 559 + ], + "lines": [ + { + "bbox": [ + 143, + 546, + 449, + 559 + ], + "spans": [ + { + "bbox": [ + 143, + 546, + 449, + 559 + ], + "type": "text", + "content": "Figure 4: Qualitative results and insights for a sample of DynamicEarthNet." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 578, + 119, + 591 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 578, + 119, + 591 + ], + "spans": [ + { + "bbox": [ + 47, + 578, + 119, + 591 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "content": "In this paper, we have introduced Conditional Change Detection, a new paradigm for change detection. We have shown that using available pre-change semantic information as input leads to significant improvements over existing methods for change detection. This holds even for a simple baseline that solely relies on feature concatenation. To further improve the performance, we have proposed MapFormer, a novel architecture outperforming its competitors in all considered settings. A limitation of our approach is" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 580, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 580, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 580, + 545, + 712 + ], + "type": "text", + "content": "the requirement of semantic pre-change information. In the future, we plan to mitigate this dependency by leveraging pre-trained models to generate pre-change maps via transfer learning. Further, we see room for improvement w.r.t. the semantic segmentation pipeline of our approach if more sophisticated techniques are integrated for this purpose. We hope this work will lead to further research following the avenue of Conditional Change Detection. In particular, we believe that more diverse datasets, more sophisticated methods, and other settings, such as uni-temporal supervision as in [33], will greatly benefit this line of research." + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16844" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 145 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 145 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 145 + ], + "type": "text", + "content": "[1] Nicolas Audebert, Bertrand Le Saux, and Sébastien Lefèvre. Joint learning from earth observation and openstreetmap data to get faster better semantic maps. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 67-75, 2017. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 146, + 287, + 179 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 146, + 287, + 179 + ], + "spans": [ + { + "bbox": [ + 53, + 146, + 287, + 179 + ], + "type": "text", + "content": "[2] Wele Gedara Chaminda Bandara and Vishal M Patel. A transformer-based siamese network for change detection. arXiv preprint arXiv:2201.01293, 2022. 1, 2, 3, 5, 6" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 180, + 287, + 223 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 180, + 287, + 223 + ], + "spans": [ + { + "bbox": [ + 53, + 180, + 287, + 223 + ], + "type": "text", + "content": "[3] Favyen Bastani and Samuel Madden. Beyond road extraction: A dataset for map update using aerial images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 11905-11914, 2021. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 224, + 287, + 269 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 224, + 287, + 269 + ], + "spans": [ + { + "bbox": [ + 53, + 224, + 287, + 269 + ], + "type": "text", + "content": "[4] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In European conference on computer vision, pages 213-229. Springer, 2020. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 270, + 287, + 302 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 270, + 287, + 302 + ], + "spans": [ + { + "bbox": [ + 53, + 270, + 287, + 302 + ], + "type": "text", + "content": "[5] Hao Chen, Zipeng Qi, and Zhenwei Shi. Remote sensing image change detection with transformers. IEEE Transactions on Geoscience and Remote Sensing, 60:1-14, 2021. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 303, + 287, + 335 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 303, + 287, + 335 + ], + "spans": [ + { + "bbox": [ + 53, + 303, + 287, + 335 + ], + "type": "text", + "content": "[6] Hao Chen and Zhenwei Shi. A spatial-temporal attention-based method and a new dataset for remote sensing image change detection. Remote Sensing, 12(10):1662, 2020. 2, 5" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 336, + 287, + 380 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 336, + 287, + 380 + ], + "spans": [ + { + "bbox": [ + 53, + 336, + 287, + 380 + ], + "type": "text", + "content": "[7] Rodrigo Caye Daudt, Bertr Le Saux, and Alexandre Boulch. Fully convolutional siamese networks for change detection. In 2018 25th IEEE International Conference on Image Processing (ICIP), pages 4063-4067. IEEE, 2018. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 380, + 287, + 424 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 380, + 287, + 424 + ], + "spans": [ + { + "bbox": [ + 53, + 380, + 287, + 424 + ], + "type": "text", + "content": "[8] Rodrigo Caye Daudt, Bertrand Le Saux, Alexandre Boulch, and Yann Gousseau. Multitask learning for large-scale semantic change detection. Computer Vision and Image Understanding, 187:102783, 2019. 2, 5" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 425, + 287, + 490 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 425, + 287, + 490 + ], + "spans": [ + { + "bbox": [ + 53, + 425, + 287, + 490 + ], + "type": "text", + "content": "[9] Sandra Díaz, Josef Settele, Eduardo S Brondízio, Hien T Ngo, John Agard, Almut Arneth, Patricia Balvanera, Kate A Brauman, Stuart HM Butchart, Kai MA Chan, et al. Pervasive human-driven decline of life on earth points to the need for transformative change. Science, 366(6471):eaax3100, 2019. 1" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 491, + 287, + 556 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 491, + 287, + 556 + ], + "spans": [ + { + "bbox": [ + 48, + 491, + 287, + 556 + ], + "type": "text", + "content": "[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 558, + 287, + 590 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 558, + 287, + 590 + ], + "spans": [ + { + "bbox": [ + 48, + 558, + 287, + 590 + ], + "type": "text", + "content": "[11] Sheng Fang, Kaiyu Li, and Zhe Li. Changer: Feature interaction is what you need for change detection. arXiv preprint arXiv:2209.08290, 2022. 2, 5, 6" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 591, + 287, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 591, + 287, + 634 + ], + "spans": [ + { + "bbox": [ + 48, + 591, + 287, + 634 + ], + "type": "text", + "content": "[12] Sheng Fang, Kaiyu Li, Jinyuan Shao, and Zhe Li. Snunet-cd: A densely connected siamese network for change detection of vhr images. IEEE Geoscience and Remote Sensing Letters, 19:1-5, 2021. 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 635, + 287, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 635, + 287, + 679 + ], + "spans": [ + { + "bbox": [ + 48, + 635, + 287, + 679 + ], + "type": "text", + "content": "[13] Shunping Ji, Shiqing Wei, and Meng Lu. Fully convolutional networks for multisource building extraction from an open aerial and satellite imagery data set. IEEE Transactions on Geoscience and Remote Sensing, 57(1):574-586, 2018. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "type": "text", + "content": "[14] Huiwei Jiang, Min Peng, Yuanjun Zhong, Haofeng Xie, Zemin Hao, Jingming Lin, Xiaoli Ma, and Xiangyun Hu. A survey on deep learning-based change detection from" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "text", + "content": "high-resolution remote sensing images. Remote Sensing, 14(7):1552, 2022. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 95, + 545, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 95, + 545, + 128 + ], + "spans": [ + { + "bbox": [ + 308, + 95, + 545, + 128 + ], + "type": "text", + "content": "[15] Lazhar Khelifi and Max Mignotte. Deep learning for change detection in remote sensing images: Comprehensive review and meta-analysis. IEEE Access, 8:126385-126400, 2020. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 129, + 545, + 182 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 129, + 545, + 182 + ], + "spans": [ + { + "bbox": [ + 308, + 129, + 545, + 182 + ], + "type": "text", + "content": "[16] Weijia Li, Conghui He, Jiarui Fang, Juepeng Zheng, Haohuan Fu, and Le Yu. Semantic segmentation-based building footprint extraction using very high-resolution satellite images and multi-source gis data. Remote Sensing, 11(4):403, 2019. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 183, + 545, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 183, + 545, + 239 + ], + "spans": [ + { + "bbox": [ + 308, + 183, + 545, + 239 + ], + "type": "text", + "content": "[17] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF international conference on computer vision, pages 10012-10022, 2021. 5, 6" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 239, + 545, + 294 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 239, + 545, + 294 + ], + "spans": [ + { + "bbox": [ + 308, + 239, + 545, + 294 + ], + "type": "text", + "content": "[18] Hyeoncheol Noh, Jingi Ju, Minseok Seo, Jongchan Park, and Dong-Geol Choi. Unsupervised change detection based on image reconstruction loss. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1352–1361, 2022. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 294, + 545, + 327 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 294, + 545, + 327 + ], + "spans": [ + { + "bbox": [ + 308, + 294, + 545, + 327 + ], + "type": "text", + "content": "[19] Gensheng Pei and Lulu Zhang. Feature hierarchical differentiation for remote sensing image change detection. IEEE Geoscience and Remote Sensing Letters, 2022. 2, 3, 4, 5, 6" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 327, + 545, + 382 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 327, + 545, + 382 + ], + "spans": [ + { + "bbox": [ + 308, + 327, + 545, + 382 + ], + "type": "text", + "content": "[20] Minseok Seo, Hakjin Lee, Yongjin Jeon, and Junghoon Seo. Self-pair: Synthesizing changes from single source for object change detection in remote sensing imagery. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 6374-6383, 2023. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 383, + 545, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 383, + 545, + 426 + ], + "spans": [ + { + "bbox": [ + 308, + 383, + 545, + 426 + ], + "type": "text", + "content": "[21] Li Shen, Yao Lu, Hao Chen, Hao Wei, Donghai Xie, Jiabao Yue, Rui Chen, Shouye Lv, and Bitao Jiang. S2looking: A satellite side-looking dataset for building change detection. Remote Sensing, 13(24):5094, 2021. 2, 5" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 426, + 545, + 481 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 426, + 545, + 481 + ], + "spans": [ + { + "bbox": [ + 308, + 426, + 545, + 481 + ], + "type": "text", + "content": "[22] Nian Shi, Keming Chen, and Guangyao Zhou. A divided spatial and temporal context network for remote sensing change detection. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 15:4897-4908, 2022. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 482, + 545, + 547 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 482, + 545, + 547 + ], + "spans": [ + { + "bbox": [ + 308, + 482, + 545, + 547 + ], + "type": "text", + "content": "[23] Wojciech Sirko, Sergii Kashubin, Marvin Ritter, Abigail Annkah, Yasser Salah Eddine Bouchareb, Yann Dauphin, Daniel Keysers, Maxim Neumann, Moustapha Cisse, and John Quinn. Continental-scale building detection from high resolution satellite imagery. arXiv preprint arXiv:2107.12283, 2021. 1" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 548, + 545, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 548, + 545, + 602 + ], + "spans": [ + { + "bbox": [ + 308, + 548, + 545, + 602 + ], + "type": "text", + "content": "[24] D. M. Theobald, C. Kennedy, B. Chen, J. Oakleaf, S. Baruch-Mordo, and J. Kiesecker. Earth transformed: detailed mapping of global human modification from 1990 to 2017. Earth System Science Data, 12(3):1953-1972, 2020. 1" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 603, + 545, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 603, + 545, + 635 + ], + "spans": [ + { + "bbox": [ + 308, + 603, + 545, + 635 + ], + "type": "text", + "content": "[25] Zhi Tian, Chunhua Shen, and Hao Chen. Conditional convolutions for instance segmentation. In European conference on computer vision, pages 282-298. Springer, 2020. 4" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 636, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 636, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 636, + 545, + 713 + ], + "type": "text", + "content": "[26] Aysim Toker, Lukas Kondmann, Mark Weber, Marvin Eisenberger, Andrés Camero, Jingliang Hu, Ariadna Pregel Hoderlein, Caglar Şenaras, Timothy Davis, Daniel Cremers, et al. Dynamicearthnet: Daily multi-spectral satellite dataset for semantic change segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 21158-21167, 2022. 1, 2, 3, 5, 7" + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16845" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 529 + ], + "type": "list", + "angle": 0, + "index": 8, + "blocks": [ + { + "bbox": [ + 48, + 72, + 286, + 105 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 286, + 105 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 286, + 105 + ], + "type": "text", + "content": "[27] Laurens Van der Maaten and Geoffrey Hinton. Visualizing data using t-sne. Journal of machine learning research, 9(11), 2008. 7, 8" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 107, + 287, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 107, + 287, + 150 + ], + "spans": [ + { + "bbox": [ + 49, + 107, + 287, + 150 + ], + "type": "text", + "content": "[28] Tete Xiao, Yingcheng Liu, Bolei Zhou, Yuning Jiang, and Jian Sun. Unified perceptual parsing for scene understanding. In Proceedings of the European conference on computer vision (ECCV), pages 418-434, 2018. 5, 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 152, + 287, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 152, + 287, + 206 + ], + "spans": [ + { + "bbox": [ + 49, + 152, + 287, + 206 + ], + "type": "text", + "content": "[29] Enze Xie, Wenhai Wang, Zhiding Yu, Anima Anandkumar, Jose M Alvarez, and Ping Luo. Segformer: Simple and efficient design for semantic segmentation with transformers. Advances in Neural Information Processing Systems, 34:12077-12090, 2021. 2, 3, 4, 5, 6" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 209, + 287, + 273 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 209, + 287, + 273 + ], + "spans": [ + { + "bbox": [ + 49, + 209, + 287, + 273 + ], + "type": "text", + "content": "[30] Lingfeng Yang, Xiang Li, Renjie Song, Borui Zhao, Jun-tian Tao, Shihao Zhou, Jiajun Liang, and Jian Yang. Dynamic mlp for fine-grained image classification by leveraging geographical and temporal information. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10945-10954, 2022. 4, 5, 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 275, + 287, + 339 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 275, + 287, + 339 + ], + "spans": [ + { + "bbox": [ + 49, + 275, + 287, + 339 + ], + "type": "text", + "content": "[31] Chenxiao Zhang, Peng Yue, Deodato Tapete, Liangcun Jiang, Boyi Shangguan, Li Huang, and Guangchao Liu. A deeply supervised image fusion network for change detection in high resolution bi-temporal remote sensing images. ISPRS Journal of Photogrammetry and Remote Sensing, 166:183-200, 2020. 2, 5" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 342, + 287, + 417 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 342, + 287, + 417 + ], + "spans": [ + { + "bbox": [ + 49, + 342, + 287, + 417 + ], + "type": "text", + "content": "[32] Sixiao Zheng, Jiachen Lu, Hengshuang Zhao, Xiatian Zhu, Zekun Luo, Yabiao Wang, Yanwei Fu, Jianfeng Feng, Tao Xiang, Philip HS Torr, et al. Rethinking semantic segmentation from a sequence-to-sequence perspective with transformers. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 6881-6890, 2021. 5, 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 419, + 287, + 473 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 419, + 287, + 473 + ], + "spans": [ + { + "bbox": [ + 49, + 419, + 287, + 473 + ], + "type": "text", + "content": "[33] Zhuo Zheng, Ailong Ma, Liangpei Zhang, and Yanfei Zhong. Change is everywhere: Single-temporal supervised object change detection in remote sensing imagery. In Proceedings of the IEEE/CVF international conference on computer vision, pages 15193-15202, 2021. 2, 8" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 475, + 287, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 475, + 287, + 529 + ], + "spans": [ + { + "bbox": [ + 49, + 475, + 287, + 529 + ], + "type": "text", + "content": "[34] Zongwei Zhou, Md Mahfuzur Rahman Siddiquee, Nima Tajbakhsh, and Jianming Liang. Unet++: A nested u-net architecture for medical image segmentation. In Deep learning in medical image analysis and multimodal learning for clinical decision support, pages 3-11. Springer, 2018. 2" + } + ] + } + ], + "index": 7 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "16846" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/80d4c617-535f-4e51-ba9c-d279342878ed_content_list.json b/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/80d4c617-535f-4e51-ba9c-d279342878ed_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..2498f3746440716f9a8cc4a9cb6afe0c47d6e4ab --- /dev/null +++ b/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/80d4c617-535f-4e51-ba9c-d279342878ed_content_list.json @@ -0,0 +1,2146 @@ +[ + { + "type": "text", + "text": "MapPrior: Bird's-Eye View Map Layout Estimation with Generative Models", + "text_level": 1, + "bbox": [ + 98, + 130, + 870, + 151 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Xiyue Zhu1 Vlas Zyrianov1 Zhijian Liu2 Shenlong Wang1 \n1University of Illinois at Urbana-Champaign 2MIT", + "bbox": [ + 212, + 179, + 754, + 218 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "https://mapprior.github.io", + "bbox": [ + 354, + 234, + 612, + 251 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 286, + 313, + 301 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Despite tremendous advancements in bird's-eye view (BEV) perception, existing models fall short in generating realistic and coherent semantic map layouts, and they fail to account for uncertainties arising from partial sensor information (such as occlusion or limited coverage). In this work, we introduce MapPrior, a novel BEV perception framework that combines a traditional discriminative BEV perception model with a learned generative model for semantic map layouts. Our MapPrior delivers predictions with better accuracy, realism and uncertainty awareness. We evaluate our model on the large-scale nuScenes benchmark. At the time of submission, MapPrior outperforms the strongest competing method, with significantly improved MMD and ECE scores in camera- and LiDAR-based BEV perception. Furthermore, our method can be used to perpetually generate layouts with unconditional sampling.", + "bbox": [ + 75, + 318, + 473, + 561 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 588, + 209, + 603 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Accurately understanding the surrounding environment of autonomous vehicles is crucial to guarantee the safety of riders and other traffic participants. Among various perception approaches, Bird's-Eye View (BEV) perception has drawn significant attention in recent years thanks to its capacity to densely model scene layouts and its tight coupling with downstream planning [80, 56, 49].", + "bbox": [ + 75, + 613, + 470, + 719 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Existing perception models encounter two challenges. The first challenge pertains to the limitations of observations, particularly in distant or occluded regions, resulting in inaccurate predictions. This may manifest in choppy, out-of-distribution, or missing map elements. The second challenge is that most existing models do not consider uncertainty and diversity in possible road layouts. Taking Fig. 1 as an example, the state-of-the-art LiDAR perception model [80] generates incoherent lane markings and sidewalks with massive gaps and cannot quantify the uncertainty and multi-modality as it only produces a single prediction per input.", + "bbox": [ + 75, + 719, + 470, + 885 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "This paper presents MapPrior, a novel BEV perception", + "bbox": [ + 96, + 885, + 468, + 901 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/75dd5875b84a2d5682ff0c4150c54471eab0faa1d3c6591af1a4bac819ae2778.jpg", + "image_caption": [ + "Figure 1: Existing predictive BEV perception models do not provide realistic scene structures (e.g., the lane and sidewalks have gaps and are not straight). In contrast, our MapPrior is able to accurately recover the layout with a learned prior. These results are validated with a quantitative comparison, showing our method's superior accuracy, realism and uncertainty awareness." + ], + "image_footnote": [], + "bbox": [ + 506, + 285, + 890, + 494 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "method that is accurate, realistic, and uncertainty-aware. At the heart of our method is a novel combination of the standard discriminative BEV perception model with a learned deep generative traffic layout prior. Incorporating generative modeling in this predictive task attempts to address the two aforementioned challenges – modeling the data distribution improves realism, and using a sampling process allows generating multiple realistic predictions. Combining our generative model with a discriminative perception model ensures that our method retains a strong predictive ability.", + "bbox": [ + 496, + 641, + 893, + 792 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Our approach comprises two steps, namely the prediction and generative steps. In the prediction step, we use an off-the-shelf BEV perception model [49] to make an initial layout estimate of the traffic scene from sensory input. In the generative step, we use our MapPrior model and initial estimate to sample one or multiple refined layouts. We perform sampling in a learned discrete latent space using a condi-", + "bbox": [ + 496, + 795, + 895, + 900 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "8228", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "tional transformer that is provided with the initial prediction. Finally, the generated tokens are passed into a decoder to output the final layout prediction, which is diverse, realistic, and coherent with the input. The encoder, decoder, and codebook of the MapPrior are trained from real-world map data in an unsupervised way.", + "bbox": [ + 75, + 90, + 470, + 181 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We benchmark our method on the nuScenes dataset against various state-of-the-art BEV perception methods with varying modalities. Our results show that MapPrior outperforms existing methods in terms of accuracy (as reflected by mean intersection-over-union), realism (as reflected by maximum-mean discrepancy), and uncertainty awareness (as reflected by expected calibration error). Furthermore, we demonstrate the unconditional generation capabilities of MapPrior by generating a realistic and consistent HD map of a $30\\mathrm{km}$ -long road.", + "bbox": [ + 75, + 181, + 470, + 333 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 76, + 345, + 218, + 361 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Self-driving perception aims to interpret sensory input and establish a representation of the surrounding environment from onboard sensors. It is a critical component for ensuring the safety and efficiency of autonomous vehicles, and various methods have been proposed to improve accuracy and robustness [71, 39]. Traditional approaches for self-driving perception involve multiple (isolated) subtasks, such as localizing against a pre-scanned environment [40, 4], object detection and tracking [38, 80, 68, 44, 50], image segmentation [62, 85, 10] and trajectory prediction [23, 64, 84, 43, 7, 82].", + "bbox": [ + 75, + 371, + 470, + 537 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Recently, there has been a growing interest in a unified Bird's Eye View (BEV) perception, both in academia [60, 87, 56, 76, 8, 50] and industry [26]. This approach aims to produce a top-down semantic layout of the traffic scene from sensory input, which is efficient, informative, and compact. Notably, the top-down layout is closely linked to downstream 2D motion planning for wheeled robots, making BEV perception particularly suitable for self-driving navigation.", + "bbox": [ + 75, + 537, + 470, + 672 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Various BEV perception modules have been studied in robotics and computer science to improve perception accuracy. These approaches typically take LiDAR [80, 38, 51, 67], multi-view camera [60, 87, 56, 76, 11, 46, 26, 59, 21], or both [81, 75, 49, 2, 57] as input, and output segmentations for road elements and detections for dynamic traffic participants like cars, cyclists or pedestrians. The majority of these methods are supervised and rely on predictive networks like CNNs [59, 67, 80, 38, 44, 60, 56] and transformers [2, 57, 11, 46, 51, 87, 21, 26, 27]. Despite their success, there are still unresolved challenges. For example, real-world traffic layouts are highly structured, with straight lane marks, strong topological relationships, and sharp road element boundaries. But such structures have proven difficult to preserve in the BEV perception output map, even", + "bbox": [ + 75, + 674, + 470, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "with state-of-the-art methods, as shown in Fig. 1. This can harm the realism of perception output and the practicality of the resulting map for motion planning. Additionally, most networks make a single layout estimation without diversity or calibrated uncertainty, leaving the autonomy vulnerable to catastrophic failure.", + "bbox": [ + 496, + 90, + 890, + 181 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "HDMapNet [42], VectorMapNet [47], and others [52, 8] have been proposed to address the issue of layout structure by introducing a vectorized output map format with implicitly structured priors. However, this approach fails to account for all layer types and still produces significant artifacts in regions with limited observations. Very recently, calibrated confidence scores have been investigated to address the aforementioned uncertainty issue [37, 13], but the inherent multi-modal uncertainty in BEV perception remains under-explored.", + "bbox": [ + 496, + 181, + 893, + 332 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In contrast, our approach leverages generative modeling as a map prior, which encodes the rich structure of the traffic scene. Our conditional generative modeling also allows us to sample multiple diverse outputs for the same input. Consequently, our results are more accurate and realistic with better multi-modal uncertainty modeling.", + "bbox": [ + 496, + 333, + 893, + 425 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Generative models. Our approach to generative BEV perception involves learning a map prior and performing conditional sampling using deep generative models. Generative models learn to capture the underlying structure of the data distribution and create new, diverse samples. Several well-known approaches include VAEs (variational autoencoders) [34, 73], which use variational inference to learn a latent space model, and autoregressive models [55], which decompose the generation problem into simpler conditional generation tasks. GANs (generative adversarial networks) [20, 83, 1, 31, 28, 72, 5] use an adversarial loss to train networks to convert noise into samples. Flow-based models [33, 15] exploit an invertible process to sample from a proposal distribution. Recently, diffusion models [14, 24] have been developed that generate samples through a denoising-diffusion process. Our method leverages vector-quantized generative models [74, 18, 9], which use a discrete-valued latent space representation that is powerful, structure-preserving, and efficient for conditional sampling. Specifically, we build our map prior on top of this approach to capture the discrete structure of the map data and generate high-quality samples.", + "bbox": [ + 496, + 441, + 893, + 776 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Generative approach for vision. Our approach belongs to the broader category of generative modeling approaches in computer vision [79, 53, 58, 69], which includes Markov random fields (MRFs), factor graphs, energy-based models, deep generative models, among others. These practices date back to the 1970s. In contrast to discriminative or predictive approaches, generative approaches often tackle the task", + "bbox": [ + 496, + 794, + 893, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "8229", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/ea864e38c632ef366352e51153a39bf086dcb0821989689642279a77c040e984.jpg", + "image_caption": [ + "Figure 2: MapPrior first makes use of an off-the-shelf perception model to generate an initial noisy estimate from the sensory input. It then encodes the noisy estimate into a discrete latent code using a generative encoder and generates various samples through a transformer-based controlled synthesis. Finally, MapPrior decodes these samples into outputs with a decoder." + ], + "image_footnote": [], + "bbox": [ + 80, + 88, + 893, + 252 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "as a marginal sampling or MAP inference problem, which is more effective at utilizing strong prior knowledge and modeling uncertainty. Representative works can be seen in low-level vision [19, 89], optical flow [70, 63], and image segmentation [66, 35, 86]. Generative approaches with conditional sampling have often been investigated in vision tasks involving multimodality or uncertainty, such as image editing [88, 28, 12, 54], image segmentation [41] and stereo estimation [16, 77]. However, few studies have explored their use in self-driving perception, despite its inherent multimodal uncertainty nature.", + "bbox": [ + 75, + 340, + 473, + 507 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Approach", + "text_level": 1, + "bbox": [ + 76, + 522, + 187, + 539 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The objective of this research is to develop a method that can generate a precise, realistic, and uncertainty-aware map layout from sensory input in one or a few modalities. To achieve this, we introduce a new framework named MapPrior that combines the predictive capability of discriminative models with the capacity of generative models to capture structures and uncertainties. We present a two-stage conditional sampling framework to explain our approach and detail the implementation of each module. Additionally, we discuss our design decisions, the learning process, and how our approach relates to previous methods.", + "bbox": [ + 75, + 547, + 472, + 715 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Overview", + "text_level": 1, + "bbox": [ + 76, + 726, + 187, + 739 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "**Formulation.** We formulate the probabilistic BEV perception problem as a conditional sampling task. Given the sensory input $\\mathbf{x} \\in \\mathcal{X}$ (which could be from a camera, LiDAR or multiple sensors), we aim to find one or multiple plausible traffic layouts $\\mathbf{y} \\in \\mathcal{Y}$ from the top-down bird's-eye view. The traffic layout $\\mathbf{y}$ is a multi-layer binary map centered at the ego vehicle. Conventional methods [49, 80, 56, 81, 76] rely on a deterministic predictive network $\\mathbf{y} = f_{\\theta}(\\mathbf{x})$ to provide a single output estimation. We propose, instead, to use a generative vector-quantized latent space model to model", + "bbox": [ + 75, + 750, + 472, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "the uncertainty and diversity. Specifically, we aim to design a conditional probability model $p_{\\theta}(\\mathbf{y}|\\mathbf{x})$ that can sample our desired output $\\mathbf{y}$ from a distribution. This allows us to explicitly model uncertainty and generate multiple plausible traffic layouts.", + "bbox": [ + 496, + 340, + 893, + 417 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Motivation. Intuitively speaking, the objective of a predictive perception model is to produce a coherent semantic layout that best represents the sensory input. However, this training objective does not necessarily optimize for structure preservation or realism. For example, minor defects in lane markers might not significantly affect cross-entropy, but could drastically impact downstream modules due to topological changes. On the other hand, a generative prior model, such as a GAN, is trained to capture realism in structures. The advantage of such a model is that it can be trained on HD map collections, without paired data, in an unsupervised manner. This insight inspires our proposed solution, which combines a predictive model with a generative model to tackle the conditional sampling task with both coherence and realism in mind.", + "bbox": [ + 496, + 440, + 895, + 667 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Inference", + "text_level": 1, + "bbox": [ + 500, + 680, + 609, + 694 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In our framework, the distribution $p_{\\theta}(\\mathbf{y}|\\mathbf{x})$ is defined implicitly using a latent model $\\mathbf{z}$ . The framework comprises of a predictive stage and a generative stage. During the predictive stage, the perception module $F(\\mathbf{x})$ generates an initial noisy estimate $\\mathbf{y}'$ for input $\\mathbf{x}$ . For the generative stage, we take inspiration from recent successful techniques in vector-quantized generation [18, 9, 61] for conditional sampling and use a VQGAN-like model to generate multiple realistic samples. To achieve this, we encode the noisy estimate $\\mathbf{y}'$ into a discrete latent code $\\mathbf{z}'$ using a generative encoder $E(\\mathbf{y}')$ . This latent code $\\mathbf{z}'$ and the sensory input $\\mathbf{x}$ then guide the generative synthesis process through a transformer-based controlled synthesis in the latent space, producing various", + "bbox": [ + 496, + 704, + 893, + 902 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "8230", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "samples $\\{\\mathbf{z}^{(k)}\\sim p(\\mathbf{z}|\\mathbf{z}',\\mathbf{x})\\}$ . Finally, these samples are decoded into multiple output samples using a decoder $G(\\cdot)$ : $\\mathbf{y}^{(k)} = G(\\mathbf{z}^{(k)})$ , which provides our final layout estimation samples. Fig. 2 depicts the overall inference framework.", + "bbox": [ + 75, + 89, + 470, + 151 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Predictive stage. The predictive stage aims to establish reliable initial layout estimation that can act as a guiding control during the conditional sampling stage. To achieve this, we have incorporated a predictive sensory backbone, VoxelNet [78, 80] for LiDAR and Swin Transformer [48] for multi-view camera inputs. The sensory backbone networks first extract features from the sensory space and then project them into bird's eye view features. For the LiDAR input, a 3D convolution backbone is utilized as a feature extractor, and the LiDAR features are flattened along the height dimension to project them to BEV. In contrast, for the camera input, a hierarchical transformer is used as a feature extractor for each view, and monocular depth estimation and view transformation are applied to project the features to BEV. The predictive model employs a convolutional segmentation head to generate the layout estimates, denoted by $\\mathbf{y}' = F(\\mathbf{x})$ . It should be noted that the resulting BEV map achieves a reasonable intersection-over-union score (IoU). However, as Fig. 1 highlights, the model suffers from unrealistic structures, missing road elements, and noise, particularly in regions with limited observations.", + "bbox": [ + 75, + 169, + 472, + 487 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Generative stage. To enhance the quality and diversity of our perception, we incorporate a generative map prior in the second stage for conditional generation. The generative map prior is built on a VQGAN architecture [18], which consists of three learnable components: the encoder $E$ , the decoder $G$ , and the codebook $\\mathcal{C} = \\{\\mathbf{c}_j\\}$ with $j$ being the code index. The encoder transforms a traffic layout into a latent feature map, where each element of the spatial map is chosen from one of the codes in the codebook as follows:", + "bbox": [ + 75, + 505, + 470, + 640 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {z} _ {t} (\\mathbf {y}) = \\underset {\\mathbf {c} _ {j} \\in \\mathcal {Z}} {\\arg \\max } \\| \\mathbf {c} _ {j} - E _ {t} (\\mathbf {y}) \\| _ {2} ^ {2}, \\quad \\forall t \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 140, + 651, + 468, + 679 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $t$ is the $t$ -th entry of the feature map $\\mathbf{z}$ . The decoder then transforms the latent code back to the layout map space: $G(\\mathbf{z}(\\mathbf{y}))$ . Sampling from this prior can be done by randomly drawing a latent code and decoding it into a layout map. The discrete-valued auto-encoder architecture greatly regularizes the output space in a structured manner, preventing it from producing unrealistic reconstructions, as shown in Fig 1.", + "bbox": [ + 75, + 689, + 468, + 795 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "During conditional sampling at inference, we first encode the noisy estimate $\\mathbf{y}'$ into a discrete latent code $\\mathbf{z}'$ using a generative encoder $E$ . This latent code $\\mathbf{z}'$ and the sensory input $\\mathbf{x}$ are then used as guidance by a transformer $T(\\mathbf{z}',\\mathbf{x})$ for the generative synthesis of the latent space, producing various samples $\\mathbf{z}^{(k)}\\sim p(\\mathbf{z}|\\mathbf{z}',\\mathbf{x}) = T(\\mathbf{z}',\\mathbf{x})$ . Specifically, we use an autoregressive scheme to progressively sample", + "bbox": [ + 75, + 796, + 470, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "each code, i.e. $p(\\mathbf{z}|\\mathbf{z}',\\mathbf{x}) = \\prod_{t}p(\\mathbf{z}_{t}|\\mathbf{z}_{< t}^{(k)},\\mathbf{z}',\\mathbf{x})$ . At the $t$ -th step, the transformer takes as input the current latent code $\\mathbf{z}_{< t}$ , the guidance code $\\mathbf{z}'$ as well as encoded sensory feature $\\mathbf{x}$ as input tokens, and outputs the next token's probability over the codebook $p(\\mathbf{z}_t|\\mathbf{z}_{< t}^{(k)},\\mathbf{z}',\\mathbf{x})$ :", + "bbox": [ + 496, + 89, + 890, + 170 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {z} _ {t} ^ {(k)} \\sim p \\left(\\mathbf {z} _ {t} \\mid \\mathbf {z} _ {< t} ^ {(k)}, \\mathbf {z} ^ {\\prime}, \\mathbf {x}\\right) \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 616, + 181, + 890, + 200 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $p(\\mathbf{z}_t|\\mathbf{z}_{< t}^{(k)},\\mathbf{z}',\\mathbf{x})$ is the conditional probability estimated from the transformer. We use nucleus sampling [25] to get multiple diverse $\\mathbf{z}^{(k)}$ , which trades-off between sampling quality and diversity. Finally, these samples are decoded into multiple output samples using a decoder $G(\\cdot)$ : $\\mathbf{y}^{(k)} = G(\\mathbf{z}^{(k)})$ , which provides our final layout estimation samples. Formally speaking, the entire second stage can be written as follows:", + "bbox": [ + 496, + 214, + 893, + 335 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {y} ^ {(k)} = G \\left(\\mathbf {z} ^ {(k)}\\right) \\text {w h e r e} \\mathbf {z} ^ {(k)} \\sim p \\left(\\mathbf {z} \\mid \\mathbf {z} ^ {\\prime}, \\mathbf {x}\\right). \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 553, + 347, + 890, + 364 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "One-step generation. To enhance inference speed, we introduce a one-step variant of MapPrior, which generates a single sample rather than multiple diverse ones. It also produces tokens in a single step, bypassing the autoregressive sampling strategy:", + "bbox": [ + 496, + 396, + 890, + 472 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {y} = G (\\mathbf {z}) \\text {w h e r e} \\mathbf {z} \\sim p (\\mathbf {z} | \\mathbf {x}). \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 591, + 484, + 890, + 500 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "This provides an effective way to trade off between the generation quality and efficiency.", + "bbox": [ + 496, + 512, + 893, + 542 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Learning", + "text_level": 1, + "bbox": [ + 500, + 551, + 607, + 568 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The training process consists of three individual components. Firstly, the perception module, denoted as $F$ , is learned to produce a reliable initial layout estimation. Secondly, the encoder, decoder, and codebook (denoted as $E$ , $G$ , and $C$ , respectively) are jointly trained to represent a strong map prior model. Lastly, given a fixed map prior model, the conditional sampling transformer $T$ is learned to sample high-quality final results. In the following, we will provide a detailed description of each component's training procedure.", + "bbox": [ + 496, + 575, + 893, + 712 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Training the perception module. To train the perception module $F$ , we follow the standard practice adopted in prior works [49, 56] and employ a binary cross-entropy loss. The objective function is defined as follows: $\\min_F - [\\mathbf{y}_{\\mathrm{gt}}\\log \\mathbf{y}']$ where $\\mathbf{y}_{\\mathrm{gt}}$ denotes the ground-truth label, and $\\mathbf{y}' = F(\\mathbf{x})$ is the corresponding prediction given the input $\\mathbf{x}$ .", + "bbox": [ + 496, + 729, + 893, + 821 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Training the map prior model. The training procedure for the map prior model involves jointly optimizing the encoder $E$ , decoder $G$ , and the fixed-size codebook $C$ in an end-to-end fashion. We use a vector-quantized auto-encoder", + "bbox": [ + 496, + 839, + 893, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "8231", + "bbox": [ + 480, + 944, + 513, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/953c05ee9133618fc0e66d6f33e24a50dc149a602caf085862d1ca357f929e74.jpg", + "image_caption": [ + "Figure 3: MapPrior can be exploited in a progressive manner to generate perpetual traffic layouts. At each step, we choose a local area to sample to fill unexplored regions and expand the frontiers." + ], + "image_footnote": [], + "bbox": [ + 78, + 87, + 197, + 193 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/cca346dd01809a0c68ebecc0918edce15d9b156e94b831f6d2894d5cec8b12c8.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 205, + 85, + 349, + 191 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/c074f79466bfcba57c21d94e5c6673eafd21f7d16ae0e1251f0236e2ed10e88a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 357, + 85, + 620, + 191 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/0e5be95741a3e5cd1d220944ef867e075e81ea614b7a2ab1bbd4d1d8897d2b8c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 629, + 88, + 890, + 191 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "to reconstruct the input data $\\mathbf{y}$ through $\\hat{\\mathbf{y}} = G(\\mathbf{z}(\\mathbf{y}_i))$ following Eq. 1. The following losses are minimized:", + "bbox": [ + 75, + 260, + 470, + 291 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\min _ {E, G, \\mathcal {C}} \\max _ {D} \\mathcal {L} _ {\\text {r e c o n}} + \\lambda_ {\\text {G A N}} \\mathcal {L} _ {\\text {G A N}} + \\mathcal {L} _ {\\text {l a t e n t}}. \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 127, + 300, + 470, + 321 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The first term, $\\mathcal{L}_{\\mathrm{recon}}$ , is the reconstruction loss, which is designed to maximize the agreement between the input $\\mathbf{y}$ and the reconstructed output:", + "bbox": [ + 76, + 330, + 468, + 375 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {r e c o n}} = \\left\\| \\hat {\\mathbf {y}} - \\mathbf {y} \\right\\| ^ {2}. \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 202, + 382, + 470, + 400 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In addition to the reconstruction loss, the second term is a GAN loss inspired by VQGAN [18] to encourage the reconstructed output to be realistic with a clear local structure and topology. A local discriminator $D(\\cdot)$ is trained to differentiate between real and reconstructed BEV layout using cross-entropy loss, and the $\\mathcal{L}_{\\mathrm{GAN}}$ loss aims to make the reconstructed image as realistic as possible through fooling the discriminator:", + "bbox": [ + 75, + 407, + 470, + 527 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {G A N}} = \\log D (\\mathbf {y}) + \\log (1 - D (\\hat {\\mathbf {y}})), \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 145, + 537, + 468, + 555 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathbf{y}$ is a real sample and $\\hat{\\mathbf{y}}$ is a reconstructed sample. Following VQGAN [18], this loss is rescaled by", + "bbox": [ + 75, + 561, + 468, + 593 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\lambda_ {\\mathrm {G A N}} = g _ {\\mathrm {r e c}} / \\left(g _ {\\mathrm {G A N}} + \\sigma\\right), \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 184, + 601, + 468, + 619 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $g_{\\mathrm{rec}}$ and $g_{\\mathrm{GAN}}$ are gradients of $\\mathcal{L}_{\\mathrm{rec}}$ and $\\mathcal{L}_{\\mathrm{GAN}}$ with respect to the last layer of the generator.", + "bbox": [ + 75, + 626, + 468, + 655 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The last term promotes the expressiveness of the codebook. We expect the latent feature $E(\\mathbf{y})$ to be close to its nearest codebook token and vice versa. Thus, the latent loss is defined as", + "bbox": [ + 75, + 656, + 468, + 715 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {l a t e n t}} = \\left\\| \\mathbf {z} - \\operatorname {s g} [ E (\\mathbf {y}) ] \\right\\| ^ {2} + \\left\\| \\operatorname {s g} [ \\mathbf {z} ] - E (\\mathbf {y}) \\right\\| ^ {2}, \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 112, + 724, + 468, + 742 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathrm{sg}[\\cdot ]$ is a gradient detach operator.", + "bbox": [ + 76, + 750, + 346, + 766 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Training the conditional sampler. Our conditional sampling transformer, denoted as $T$ , is trained in the latent code space to sample high-likelihood latent codes given input controlling guidance. Given a paired input and output $(\\mathbf{x},\\mathbf{y})$ and fixed perception module $F$ , map prior model $E,G,C$ , the transformer is trained using the following objective:", + "bbox": [ + 75, + 782, + 470, + 873 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\min _ {T} \\mathcal {L} _ {\\mathrm {C E}} + \\mathcal {L} _ {\\text {o u t}}. \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 210, + 882, + 468, + 904 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The first loss, $\\mathcal{L}_{\\mathrm{CE}}$ , optimizes the transformer to maximize the estimated probability of the latent code of the ground-truth layout. We use a cross-entropy loss between the transformer's estimated probability $T(\\mathbf{z}',\\mathbf{x})$ and the ground-truth sample $\\mathbf{y}$ :", + "bbox": [ + 498, + 260, + 893, + 335 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {C E}} = \\sum_ {t} \\sum_ {i} \\mathbf {y} _ {i, t} \\log T _ {i, t} \\left(\\mathbf {z} ^ {\\prime}, \\mathbf {x}\\right), \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 578, + 347, + 892, + 378 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where, $i$ represents the $i$ -th output label, and $t$ represents the $t$ -th autoregressive step.", + "bbox": [ + 498, + 388, + 890, + 417 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Although making the latent code closer to the ground-truth map's latent code is essential, it is not sufficient to ensure high output fidelity. Hence, we include an additional reconstruction output loss that encourages the transformer to favor samples that produce high-accuracy layouts. Similar to the reconstruction loss in auto-encoding training, an L2 reconstruction loss is used:", + "bbox": [ + 496, + 417, + 892, + 522 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {o u t}} = \\left\\| \\mathbf {y} - \\hat {\\mathbf {y}} \\right\\| _ {2} ^ {2}, \\tag {12}\n$$\n", + "text_format": "latex", + "bbox": [ + 632, + 534, + 892, + 551 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathbf{y}$ is the true map and $\\hat{\\mathbf{y}}$ is the predicted map. Note that codebook selection in latent code space is non-differentiable; thus, we use Gumbel-Softmax [29] to ensure differentiability in practice throughout the training processes.", + "bbox": [ + 496, + 563, + 893, + 623 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.4. Discussions", + "text_level": 1, + "bbox": [ + 500, + 632, + 624, + 646 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Uncertainty quantification. Our latent transformer offers diverse results $\\mathbf{y}^{(k)}$ by using a conditional sampling scheme. By estimating the variance of $\\mathbf{y}^{(k)}$ , we can estimate the uncertainty map for our results. By using the average of $\\mathbf{y}^{(k)}$ , we aggregate the diverse result samples to a more stable and better calibrated results.", + "bbox": [ + 496, + 655, + 893, + 744 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Perpetual layout generation. Our trained map prior enables the continuous generation of realistic and varied driving sequences, which are extremely valuable for content creation and autonomous driving simulations. We use a progressive generation strategy, which builds upon prior works [3, 17, 45, 65, 18, 9]. The strategy involves iteratively expanding our visual horizon and generating new content by leveraging our map prior model to fill in the previously unseen areas. We illustrate this process in Fig. 3.", + "bbox": [ + 496, + 763, + 893, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "8232", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/6cbba0f7ff5284bda1741d56e27055e23055c2780b2abc46218a98071460892c.jpg", + "table_caption": [ + "Table 1: Quantitative results of BEV map segmentation on nuScenes. Our MapPrior achieves better accuracy (IoU), realism (MMD) and uncertainty awareness (ECE) than discriminative BEV perception baselines." + ], + "table_footnote": [], + "table_body": "
ModalityIoU (↑)MMD (↓)ECE (↓)
DrivablePed. XWalkwayStop LineCarparkDividerMean
OFT [60]C74.035.345.927.535.933.942.154.50.045
LSS [56]C75.438.846.330.339.136.544.443.20.041
BEVFusion-C [49]C81.754.858.447.450.746.456.639.60.038
MapPrior-CC81.754.658.346.753.345.156.728.40.026
MapPrior-C (1 step)C81.654.658.446.853.945.156.728.7-
PointPillars [38]L72.043.153.129.727.737.543.8153.00.111
BEVFusion-L [80, 49]L75.648.457.536.531.741.948.6115.20.090
MapPrior-LL81.049.758.037.538.242.451.135.80.038
MapPrior-L (1 step)L80.149.057.837.833.042.550.050.2-
PointPainting [75]C+L75.948.557.136.924.541.949.1109.80.099
MVP [81]C+L76.148.757.036.933.042.249.0115.30.096
BEVFusion [49]C+L85.560.567.652.057.053.762.721.60.038
MapPrior-CLC+L85.361.467.151.760.053.363.128.00.020
MapPrior-CL (1 step)C+L85.361.367.051.759.653.163.028.1-
", + "bbox": [ + 80, + 130, + 890, + 388 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 425, + 209, + 443 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We evaluate our MapPrior on BEV map segmentation and generation tasks for both LiDAR and camera modalities. We evaluate our approach to generate an accurate and realistic traffic layout both quantitatively and qualitatively in Sec. 4.2. We show how output loss and BEV features can affect our performance in Tab. 2. We finally estimate how our model can generate diverse samples and how our model is calibrated using the diverse samples in Fig. 5 and 6. Specifically, we are interested in seeing how using a generative prior affects accuracy (reflected by mIoU), realism (reflected by MMD), and model calibration (reflected by ECE).", + "bbox": [ + 75, + 450, + 473, + 618 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Experimental Setup", + "text_level": 1, + "bbox": [ + 76, + 628, + 267, + 645 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Datasets. We evaluate our model on nuScenes [6], a large-scale outdoor autonomous driving dataset containing 1000 driving scenes, consisting of 700 scenes for training, 150 for validation, and 150 scenes for testing. It has around 40,000 annotated key-frames, each with six monocular camera images encompassing a 360-degree FoV (used by camera models), and a 32-beam LiDAR scan (used by LiDAR models). We follow the train/validation split provided by nuScenes. We evaluate all models on the validation set following common practices in BEV layout estimation [49, 56]. The ground truth segmentation map is provided by nuScenes and was labeled manually [6]. We rasterized the map layers from the nuScenes map into the ego frame.", + "bbox": [ + 75, + 652, + 470, + 849 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Metrics. We provide quantitative results for both segmentation and generative tasks. For BEV map segmentation,", + "bbox": [ + 75, + 869, + 472, + 902 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "our metric is the Intersection-over-Union (IoU score) for six map classes (drivable area, pedestrian crossing, walkway, stop line, car-parking area, and lane divider), as well as the mean IoU averaged over all six map classes. Since different classes may overlap, we separately compare the IoU score for each class. For all baseline predictive models, we choose the best threshold that maximizes IoU for comparison to ensure no bias is introduced due to the suboptimal threshold selection. For MapPrior, we simply use 0.5 as the threshold.", + "bbox": [ + 496, + 426, + 893, + 561 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To evaluate generated map layout realism, we use the maximum mean discrepancy (MMD) metric. MMD effectively measures the distance between two distributions of two sets of samples by measuring the squared difference of their mean in different spaces:", + "bbox": [ + 496, + 563, + 893, + 638 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathrm {M M D} = \\sum_ {i} ^ {n} \\sum_ {i ^ {\\prime}} ^ {n} k (\\mathbf {x} _ {i}, \\mathbf {x} _ {i ^ {\\prime}}) / n ^ {2} + \\sum_ {j} ^ {m} \\sum_ {j ^ {\\prime}} ^ {m} k (\\mathbf {x} _ {j}, \\mathbf {x} _ {j ^ {\\prime}}) / m ^ {2} \\\\ - 2 \\cdot \\sum_ {i} ^ {n} \\sum_ {j} ^ {m} k \\left(\\mathbf {x} _ {i}, \\mathbf {x} _ {j}\\right) / n m. \\tag {13} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 504, + 647, + 890, + 744 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To evaluate a set of predicted layouts, we compare it with a set of ground truth layouts from nuScenes.", + "bbox": [ + 496, + 746, + 890, + 775 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To evaluate uncertainty in our diversity results, we use Expected Calibration Error (ECE) [36, 22]. ECE compares output probabilities to model accuracy. It splits the results into several bins and measures a weighted average discrepancy between accuracy and confidence within each bin:", + "bbox": [ + 496, + 776, + 893, + 852 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {E C E} = \\sum_ {b} ^ {B} n _ {b} | \\operatorname {a c c} (b) - \\operatorname {c o n f} (b) | / n, \\tag {14}\n$$\n", + "text_format": "latex", + "bbox": [ + 570, + 861, + 893, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "8233", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/8c0a7cd2ec75e19801d69437c071be755b8dba191b69914ad980e8322936f809.jpg", + "image_caption": [ + "LiDAR" + ], + "image_footnote": [], + "bbox": [ + 91, + 87, + 197, + 248 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c6056e214c5e7ad83f84a11833a522ce91be20bd4309524ee214f31e0d2237b6.jpg", + "image_caption": [ + "PointPillars" + ], + "image_footnote": [], + "bbox": [ + 212, + 88, + 370, + 248 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/91e9b2d302669c58fc7b2a539837ba5fd40a41af99df56172a922038615ffe52.jpg", + "image_caption": [ + "BEVFusion-L" + ], + "image_footnote": [], + "bbox": [ + 385, + 88, + 542, + 250 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/59a64753780a79c0d7b7d9e81693a0c999777c379f5f8125a530f956e3aba46a.jpg", + "image_caption": [ + "MapPrior-L (Ours)" + ], + "image_footnote": [], + "bbox": [ + 558, + 88, + 714, + 250 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/821ca6780cdf4b03e11c80221f178af8630bc5c138ca0fc20418c995106d8855.jpg", + "image_caption": [ + "Ground Truth" + ], + "image_footnote": [], + "bbox": [ + 733, + 88, + 885, + 250 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/3b004600bd4c1323365e21a3afa15a06d6a61252d7a09e58d8e80ac180ac310e.jpg", + "image_caption": [ + "Camera" + ], + "image_footnote": [], + "bbox": [ + 91, + 285, + 197, + 339 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/d4f3cb944cbccd6bec267d3c2352aaf29f95d9c19f45aecaaf682c914b0025a7.jpg", + "image_caption": [ + "LSS" + ], + "image_footnote": [], + "bbox": [ + 215, + 268, + 370, + 349 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/7d5c983dc468668b9c00dfeca3308d9d1abf3d45bda8c6afad51e49a9caf4198.jpg", + "image_caption": [ + "BEVFusion-C" + ], + "image_footnote": [], + "bbox": [ + 385, + 270, + 542, + 349 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/03c37265a3456af4e3481128b0c1bf03f54f4e6935a7c62f5178e76355360829.jpg", + "image_caption": [ + "MapPrior-C (Ours)" + ], + "image_footnote": [], + "bbox": [ + 558, + 270, + 714, + 349 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c1619230200892b0940f88f483493b5dd77e80f150431ee1ed19cd075f44d580.jpg", + "image_caption": [ + "Ground Truth" + ], + "image_footnote": [], + "bbox": [ + 733, + 270, + 887, + 349 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c105640b6fbfec181b3a8bad34335c909a84df41f252be75113bf336096f4633.jpg", + "image_caption": [ + "LiDAR" + ], + "image_footnote": [], + "bbox": [ + 91, + 373, + 194, + 450 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/d86c05ac6253002579e4dfbf6d49c953b0d943a0cc897e4464eac1002b6ba57c.jpg", + "image_caption": [ + "Camera" + ], + "image_footnote": [], + "bbox": [ + 222, + 382, + 346, + 441 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/7a7434b0aadebd182e7ec8587e88bd28cef3fb2a8640ce61279bbc34f43d8115.jpg", + "image_caption": [ + "BEVFusion-CL" + ], + "image_footnote": [], + "bbox": [ + 388, + 369, + 542, + 449 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/5a2968f5a77acc40447164e0f8b6da72c064db29f42f328f1c152df7797271c4.jpg", + "image_caption": [ + "MapPrior-CL (Ours)" + ], + "image_footnote": [], + "bbox": [ + 563, + 369, + 717, + 449 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/ad1364e78541555d8ca3946ecdb59ce51a9525c567e783f93e0d822aabbb166c.jpg", + "image_caption": [ + "Ground Truth" + ], + "image_footnote": [], + "bbox": [ + 738, + 369, + 892, + 449 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/6a89fa43641c322d2b06e5ec347db4dea8b7add94db677290eae51de8bd95f96.jpg", + "image_caption": [ + "Figure 4: Qualitative results of BEV map segmentation on nuScenes. Discriminative BEV perception baselines produce results with clear artifacts (e.g., lane markings are discontinuous, roads and pedestrian walkways have unrealistic gaps, etc.). In contrast, our MapPrior produces semantic map layouts that are clean, realistic, and in-distribution." + ], + "image_footnote": [], + "bbox": [ + 86, + 547, + 210, + 643 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/04f60e24881c3e2c2fcf8aeaace46a1ad8b9dd74188d036439cbf2dbce2cf6f3.jpg", + "image_caption": [ + "Input" + ], + "image_footnote": [], + "bbox": [ + 86, + 645, + 210, + 738 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/e5e48dccf8aca33770969d1ea6f6fae01a0231033930f7a2ed982897cd680ef1.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 223, + 570, + 348, + 628 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/0544d9923024765b5bbe5c09d25563d7a95a7e70e8b2742f7abd7e304205e927.jpg", + "image_caption": [ + "GT" + ], + "image_footnote": [], + "bbox": [ + 223, + 642, + 349, + 739 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/e72a1a1e7221652d0c2f5a07befa49eed0c07fb61420f9911088fb271af0de4c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 359, + 570, + 483, + 628 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c8c4c631599a0ea43c374d792df7fe1bacff4faa433e871ca382a49974a218a4.jpg", + "image_caption": [ + "Our Sample 1" + ], + "image_footnote": [], + "bbox": [ + 359, + 643, + 485, + 738 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c2328f4c083ac74f2c2a991d1014b839d6f93caca949c146b6ec7a90159fdbed.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 496, + 569, + 620, + 628 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/225cf090e1996ed4cdd3121d861aa83f2b8417261eb64ecfd93cc7a20e7acf02.jpg", + "image_caption": [ + "Our Sample 2" + ], + "image_footnote": [], + "bbox": [ + 496, + 643, + 620, + 738 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/0a3e9d834cf49ab30040649b7970ed1690dc6669521882bbaaf0674a53ddb1a3.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 633, + 569, + 756, + 630 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/e0a1ae028c9ca7ecd9a704888f1276391f3ea02ddd47db34de9fa42d326b775e.jpg", + "image_caption": [ + "Our Sample 3", + "Figure 5: Qualitative results of diversity on NuScenes." + ], + "image_footnote": [], + "bbox": [ + 635, + 643, + 756, + 738 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/a7159444af1fcc0bdfc49e41d8b459001c907787a889b5e736fe00efd4e23d2e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 772, + 549, + 893, + 643 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/6197df6b885b76d0627b30d1661d1dc12fbc18fa526987ef51cb8ad08044ae2a.jpg", + "image_caption": [ + "Uncertainty Map" + ], + "image_footnote": [], + "bbox": [ + 772, + 643, + 893, + 738 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "where acc is the empirical accuracy, and conf is the estimated confidence for each bin, $n_b$ is the # of samples per each bin and $n$ is the total # of samples. ECE is an important metric in BEV map segmentation, as ignoring uncertainties can lead to bad consequences in driving planning. We gener", + "bbox": [ + 75, + 810, + 470, + 886 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "ate 15 diverse outputs for every instance and use the mean as the confidence. The baseline model is trained end-to-end with cross-entropy loss, so the predictions produced by the softmax function are assumed to be the pseudo probabilities.", + "bbox": [ + 500, + 810, + 893, + 869 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "8234", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/4923dbae83ba9d325b35ff0f5a967f0c89c3a518cf70478d1aab7ed98c7044a7.jpg", + "image_caption": [ + "LiDAR" + ], + "image_footnote": [], + "bbox": [ + 86, + 87, + 189, + 246 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/36bd2ed41022c4b45941e5e0b362513f447d1de006d59ce9a94862f6d85355fd.jpg", + "image_caption": [ + "Prediction" + ], + "image_footnote": [], + "bbox": [ + 202, + 87, + 305, + 244 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/007f185348c48b58927f8ca278f458835c16eb4625a6379e33692aa2ab4bff99.jpg", + "image_caption": [ + "Uncertainty", + "BEVFusion-C" + ], + "image_footnote": [], + "bbox": [ + 320, + 87, + 423, + 244 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/dc5aaf86de4d38714bface5b89d7901bd31514f2effdb6580628cb1438e871ce.jpg", + "image_caption": [ + "Error Map", + "Figure 6: Prediction, uncertainty, and error map comparison between BEVFusion-C and MapPrior. BEVFusion generates a misguided uncertainty boundary by giving high weight to areas where map elements are unlikely to be. In comparison, MapPrior's uncertainty is constrained to map element boundaries. This is further confirmed with the error map, where MapPrior's uncertainty map closely matches the error map." + ], + "image_footnote": [], + "bbox": [ + 437, + 87, + 540, + 244 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/e5cdc9ad14a4d8f2babf0ae2a67e60ef3e14e81ef65dff7a611f96ef0d7ffb85.jpg", + "image_caption": [ + "Prediction" + ], + "image_footnote": [], + "bbox": [ + 553, + 87, + 656, + 244 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/2e0d8852bf49a33ce7b9dd9e0cda87589ed9864567521be4667122d23cf8c05c.jpg", + "image_caption": [ + "Uncertainty", + "MapPrior" + ], + "image_footnote": [], + "bbox": [ + 669, + 87, + 772, + 244 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/866965474c9d5def163e49624c80ddd3e183bb1da3ca001d82c9b8387564d88a.jpg", + "image_caption": [ + "Error Map" + ], + "image_footnote": [], + "bbox": [ + 787, + 87, + 890, + 244 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/1de20aea8f05c9c46b0c044a8cbb1f6dd90be5b50db7915ceaad8c82824b5543.jpg", + "table_caption": [ + "Table 2: Ablation studies for MapPrior on nuScenes." + ], + "table_footnote": [], + "table_body": "
Output Loss LoutT(z') or T(z', x)mIoU (↑)MMD (↓)
-T(z')45.633.3
✓T(z')49.045.6
✓T(z', x)51.135.8
", + "bbox": [ + 84, + 409, + 460, + 481 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Baselines. For LiDAR-only segmentation, we use Point-Pillars [38], and BEVFusion-L [49, 80] as our baselines. To the best of our knowledge, BEVFusion-L is the current state-of-the-art method in LiDAR-based BEV map segmentation.", + "bbox": [ + 75, + 520, + 470, + 580 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "For camera-only segmentation, our baseline model are LSS [56], OFT [60], and BEVFusion-C [49]. Among them, BEVFusion-C is the current state-of-the-art model with a significantly higher IoU score than other methods. We use open-source code from BEVFusion. We also provide results of multi-modal models [49, 75, 81] for reference.", + "bbox": [ + 75, + 580, + 468, + 672 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Implementation details. Following [49], we perform segmentation in a $[-50\\mathrm{m}, 50\\mathrm{m}] \\times [-50\\mathrm{m}, 50\\mathrm{m}]$ region around the ego car with a resolution of 0.5 meters/pixel, resulting in a final image size of $200 \\times 200$ . Since map classes may overlap, our model performs binary segmentation for all classes. The encoder and decoder comprise four downsampling and four upsampling blocks processing a series of 128-256-512-256-128 channels. Each block comprises 2 reset blocks and one convolution and uses sigmoid activation and GroupNorm. The resolution of the latent space is [12,12].", + "bbox": [ + 75, + 688, + 470, + 839 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "For the generative step, we train a minGPT [30] transformer conditioned on the generated sequence, extracted BEV features, and the initial noisy map. We train the whole model using Adam [32] with a learning rate of 9.0e-6. The", + "bbox": [ + 75, + 839, + 470, + 901 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "transformer's BEV feature encoder for the transformer has a similar structure to the model encoder consisting of 3 down-sampling blocks. The BEV feature encoder converts the original BEV features shaped [128, 128] into latent space tokens shaped [12, 12]. We apply a multiplier of 100 on the output loss to balance the magnitude of different losses.", + "bbox": [ + 496, + 383, + 893, + 474 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.2. Map Segmentation as Generation", + "text_level": 1, + "bbox": [ + 500, + 482, + 794, + 498 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Quantitative results. We show our quantitative results for map segmentation in Tab. 1. The results show that MapPrior achieves state-of-the-art performance. Comparing with BEVFusion-L, our MapPrior-L offers $2.5\\%$ improvement in mIoU, which is brought purely by our proposed generative stage. Furthermore, MapPrior provides a substantial improvement in the MMD score compared to baselines. MMD is a metric of distance between the generated layout predictions and the ground truth distribution. This shows that MapPrior's outputs closely match the ground truth data distribution. In addition, this stark difference in MapPrior's MMD performance compared to the baselines implies that the realism metric and precision metric are not closely coupled. It is possible to achieve higher IoU while generating non-realistic samples, or vice versa. Our approach simultaneously pushes the limit of the two.", + "bbox": [ + 496, + 505, + 893, + 744 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Moreover, inference speed is vital for MapPrior. Using an RTX A6000 GPU, we compared the inference speeds of our model and BEVFusion in terms of frames per second (FPS). Our findings are presented in Tab. 3. These results indicate that one-step MapPrior is significantly closer to real-time performance compared to the standard MapPrior, with only a minor trade-off in IoU for increased uncertainty awareness.", + "bbox": [ + 496, + 747, + 893, + 853 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Qualitative results. We show our qualitative results in Fig. 4. Compared to other methods, MapPrior can consist", + "bbox": [ + 498, + 869, + 893, + 901 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "8235", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/2b991d78bdfd586d60cb83d7c6a8fe1597c651151e1d79e7bb8489f387f11cdc.jpg", + "image_caption": [ + "Figure 7: Results for perpetual traffic scene generation. Two road subsections are shown here." + ], + "image_footnote": [], + "bbox": [ + 138, + 85, + 831, + 214 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/4f7fc4bd874aa545cda7707971eaf0013ea513cb52d72bcf4e206ee218887927.jpg", + "table_caption": [ + "Table 3: Performance of one-step MapPrior." + ], + "table_footnote": [], + "table_body": "
ModalitymIoU (↑)MMD (↓)FPS
BEVFusion-C [49]C56.639.68.85
MapPrior-CC56.728.40.60
MapPrior-C (1 step)C56.728.74.26
BEVFusion-L [80, 49]L48.6115.27.52
MapPrior-LL51.135.80.57
MapPrior-L (1 step)L50.050.24.88
BEVFusion [49]C+L62.721.65.52
MapPrior-CLC+L63.128.00.55
MapPrior-CL (1 step)C+L63.028.13.61
", + "bbox": [ + 78, + 279, + 470, + 448 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "tently generate coherent and realistic class predictions within the entire map region. Our model has a more coherent divider layout, whereas the baseline methods usually have broken/missing lane dividers. In the baseline methods, the stopline is often jagged and appears disconnected from the road. In distant areas from the ego car, our model tries to make a plausible layout estimate when other methods fail due to limited observations (this is especially noticeable in the pedestrian walkways). The edges from our method are also more smooth, resulting in a more realistic estimation.", + "bbox": [ + 75, + 473, + 468, + 623 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Diversity and uncertainty calibration. We show that our model can produce a better-calibrated layout with diversity. In Fig. 5, we show that our model can generate multiple diverse and feasible layouts, All of which are realistic.", + "bbox": [ + 75, + 648, + 468, + 708 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "By aggregating the diverse samples, our model can produce a calibrated uncertainty map. We show our results in Fig. 6. Compared to the baselines (which are unable to generate multiple samples), our uncertainty map aligns with the error map much more accurately. ECE scores in Tab. 1 further validate this quantitatively.", + "bbox": [ + 75, + 709, + 468, + 801 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Perpetual generation. We show our qualitative results for generating 'infinite' roads in Fig. 7. We have generated a single $30\\mathrm{km}$ long road. Due to size constraints, we are only able to show a subsection. The generated traffic scene contains a highway with intermittent intersections resembling a", + "bbox": [ + 75, + 825, + 470, + 902 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "road layout in a city. We provide the entire road as a gif in our supplementary materials.", + "bbox": [ + 496, + 255, + 890, + 286 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "4.3. Discussions", + "text_level": 1, + "bbox": [ + 500, + 292, + 624, + 306 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Ablation studies. To justify our design, we provide ablation studies in Tab. 2. L2 loss at the output end changes the model's optimization target. It puts more weight on generating accurate results as opposed to generating i.i.d. data. Therefore, the model achieves a higher IoU score at the cost of a slightly worse MMD. Providing the transformer with BEV features boosts the performance by around $3\\%$ in the IoU score, and decreases MMD by around $21\\%$ .", + "bbox": [ + 496, + 316, + 893, + 436 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Inference speed. Inference speed is essential for MapPrior, especially given the real-time demands of autonomous driving. While transformers offer remarkable generative abilities, they inherently slow down performance due to their sequential token generation process. Moreover, the need for MapPrior to produce diverse outcomes further curtails its inference speed. To address this, we introduced the one-step variant of MapPrior, which predicts a single sample for each input and generates all tokens simultaneously. As evidenced in Tab. 3, the one-step MapPrior registers a marginally worse MMD score and falls short in uncertainty awareness. Nonetheless, the one-step MapPrior markedly outpaces the standard MapPrior in speed.", + "bbox": [ + 496, + 454, + 893, + 650 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 661, + 617, + 676 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This paper presents MapPrior, a novel generative method for performing BEV perception. The core idea is to leverage a learned generative prior over traffic layouts to provide diverse and accurate layout estimations, which potentially enable more informed decision-making and motion planning. Our experiments show that our approach produces more realistic scene layouts, enhances accuracy, and better calibrates uncertainty compared to current methods.", + "bbox": [ + 496, + 686, + 893, + 808 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement. The project is partially funded by the Illinois Smart Transportation Initiative STII-21-07, an Amazon Research Award, an Intel Research Gift, and an IBM IIDAI grant. We also thank NVIDIA for the Academic Hardware Grant. VZ is supported by the Frontier Fellowship.", + "bbox": [ + 496, + 825, + 893, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "8236", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 174, + 106 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Martin Arjovsky, Soumith Chintala, and Léon Bottou. Wasserstein generative adversarial networks. In ICML, 2017. 2", + "[2] Xuyang Bai, Zeyu Hu, Xinge Zhu, Qingqiu Huang, Yilun Chen, Hongbo Fu, and Chiew-Lan Tai. Transfusion: Robust lidar-camera fusion for 3d object detection with transformers. In CVPR, 2022. 2", + "[3] Connelly Barnes, Eli Shechtman, Adam Finkelstein, and Dan B Goldman. PatchMatch: A randomized correspondence algorithm for structural image editing. 2009. 5", + "[4] Ioan Andrei Barsan, Shenlong Wang, Andrei Pokrovsky, and Raquel Urtasun. Learning to localize using a lidar intensity map. In CoRL, 2018. 2", + "[5] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. In ICLR, 2019. 2", + "[6] Holger Caesar, Varun Bankiti, Alex H. Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In CVPR, 2020. 6", + "[7] Sergio Casas, Wenjie Luo, and Raquel Urtasun. Intentnet: Learning to predict intention from raw sensor data. In CoRL, 2018. 2", + "[8] Sergio Casas, Abbas Sadat, and Raquel Urtasun. Mp3: A unified model to map, perceive, predict and plan. In CVPR, 2021. 2", + "[9] Huiwen Chang, Han Zhang, Lu Jiang, Ce Liu, and William T. Freeman. Maskgit: Masked generative image transformer. In CVPR, 2022. 2, 3, 5", + "[10] Bowen Cheng, Alexander G. Schwing, and Alexander Kirillov. Per-pixel classification is not all you need for semantic segmentation. In NeurIPS, 2021. 2", + "[11] Kashyap Chitta, Aditya Prakash, and Andreas Geiger. Neat: Neural attention fields for end-to-end autonomous driving. In CVPR, 2021. 2", + "[12] Min Jin Chong and David Forsyth. Jojogan: One shot face stylization. In ECCV, 2022. 3", + "[13] Laurene Claussmann, Marc Revilloud, Dominique Gruyer, and Sébastien Glaser. A review of motion planning for highway autonomous driving. 2020. 2", + "[14] Prafulla Dhariwal and Alex Nichol. Diffusion models beat gans on image synthesis. In NeurIPS, 2021. 2", + "[15] Laurent Dinh, David Krueger, and Yoshua Bengio. Nice: Non-linear independent components estimation. In ICLR (Workshop), 2014. 2", + "[16] Shivam Duggal, Shenlong Wang, Wei-Chiu Ma, Rui Hu, and Raquel Urtasun. Deepruner: Learning efficient stereo matching via differentiable patchmatch. In ICCV, 2019. 3", + "[17] Alexei A. Efros and William T. Freeman. Image quilting for texture synthesis and transfer. In SIGGRAPH, 2001. 5", + "[18] Patrick Esser, Robin Rombach, and Björn Ommer. Taming transformers for high-resolution image synthesis. In CVPR, 2021. 2, 3, 4, 5", + "[19] W.T. Freeman and E.C. Pasztor. Learning low-level vision. In CVPR, 1999. 3" + ], + "bbox": [ + 78, + 114, + 470, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[20] Ian J. Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. In NeurIPS, 2014. 2", + "[21] Nikhil Gosala and Abhinav Valada. Bird's-eye-view panoptic segmentation using monocular frontal view images. 2022. 2", + "[22] Chuan Guo, Geoff Pleiss, Yu Sun, and Kilian Q. Weinberger. On calibration of modern neural networks. In ICML, 2017. 6", + "[23] Agrim Gupta, Justin Johnson, Li Fei-Fei, Silvio Savarese, and Alexandre Alahi. Social gan: Socially acceptable trajectories with generative adversarial networks. In CVPR, 2018. 2", + "[24] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. In NeurIPS, 2020. 2", + "[25] Ari Holtzman, Jan Buys, Li Du, Maxwell Forbes, and Yejin Choi. The curious case of neural text degeneration. In ICLR, 2020. 4", + "[26] Anthony Hu, Zak Murez, Nikhil Mohan, Sofia Dudas, Jeffrey Hawke, Vijay Badrinarayanan, Roberto Cipolla, and Alex Kendall. FIERY: Future instance segmentation in bird's-eye view from surround monocular cameras. In ICCV, 2021. 2", + "[27] Junjie Huang, Guan Huang, Zheng Zhu, and Dalong Du. BEVDet: High-Performance Multi-Camera 3D Object Detection in Bird-Eye-View. arXiv preprint arXiv:2112.11790, 2021. 2", + "[28] Phillip Isola, Jun-Yan Zhu, Tinghui Zhou, and Alexei A. Efros. Image-to-image translation with conditional adversarial networks. In CVPR, 2017. 2, 3", + "[29] Eric Jang, Shixiang Gu, and Ben Poole. Categorical Reparaterization with Gumbel-Softmax. In ICLR, 2017. 5", + "[30] Andrej Karpathy. Mingpt. https://github.com/karpathy/minGPT, 2022.8", + "[31] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In CVPR, 2019. 2", + "[32] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. 8", + "[33] Diederik P. Kingma and Prafulla Dhariwal. Glow: Generative flow with invertible 1x1 convolutions. In NeurIPS, 2018. 2", + "[34] Diederik P Kingma and Max Welling. Auto-encoding variational bayes. In ICLR, 2014. 2", + "[35] Philipp Kähenbuhl and Vladlen Koltun. Efficient inference in fully connected crfs with gaussian edge potentials. In NeurIPS, 2011. 3", + "[36] Ananya Kumar, Percy Liang, and Tengyu Ma. Verified uncertainty calibration. In NeurIPS, 2019. 6", + "[37] Markus Kängsepp and Meelis Kull. Calibrated perception uncertainty across objects and regions in bird's-eye-view. In NeurIPS (Workshop), 2022. 2", + "[38] Alex H. Lang, Sourabh Vora, Holger Caesar, Lubing Zhou, Jiong Yang, and Oscar Beijbom. Pointpillars: Fast encoders for object detection from point clouds. In CVPR, 2019. 2, 6, 8", + "[39] Jesse Levinson, Jake Askeland, Jan Becker, Jennifer Dolson, David Held, Soeren Kammel, J. Zico Kolter, Dirk Langer, Oliver Pink, Vaughan Pratt, Michael Sokolsky, Ganymed Stanek, David Stavens, Alex Teichman, Moritz Werling, and" + ], + "bbox": [ + 501, + 92, + 893, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "8237", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Sebastian Thrun. Towards fully autonomous driving: Systems and algorithms. In IV, 2011. 2", + "[40] Jesse Levinson and Sebastian Thrun. Robust vehicle localization in urban environments using probabilistic maps. In ICRA, 2010. 2", + "[41] Daiqing Li, Junlin Yang, Karsten Kreis, Antonio Torralba, and Sanja Fidler. Semantic segmentation with generative models: Semi-supervised learning and strong out-of-domain generalization. In CVPR, 2021. 3", + "[42] Qi Li, Yue Wang, Yilun Wang, and Hang Zhao. Hdmapnet: An online hd map construction and evaluation framework. In ICRA, 2022. 2", + "[43] Ming Liang, Bin Yang, Rui Hu, Yun Chen, Renjie Liao, Song Feng, and Raquel Urtasun. Learning lane graph representations for motion forecasting. In ECCV, 2020. 2", + "[44] Ming Liang, Bin Yang, Shenlong Wang, and Raquel Urtasun. Deep continuous fusion for multi-sensor 3d object detection. In ECCV, 2018. 2", + "[45] Andrew Liu, Richard Tucker, Varun Jampani, Ameesh Makadia, Noah Snavely, and Angjoo Kanazawa. Infinite nature: Perpetual view generation of natural scenes from a single image. In ICCV, 2021. 5", + "[46] Yingfei Liu, Tiancai Wang, Xiangyu Zhang, and Jian Sun. Petr: Position embedding transformation for multi-view 3d object detection. In ECCV, 2022. 2", + "[47] Yicheng Liu, Yuan Yuantian, Yue Wang, Yilun Wang, and Hang Zhao. Vectormapnet: End-to-end vectorized hd map learning. arXiv preprint arXiv:2206.08920, 2022. 2", + "[48] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin Transformer: Hierarchical Vision Transformer using Shifted Windows. In ICCV, 2021. 4", + "[49] Zhijian Liu, Haotian Tang, Alexander Amini, Xinyu Yang, Huizi Mao, Daniela Rus, and Song Han. Bevfusion: Multi-task multi-sensor fusion with unified bird's-eye view representation. In ICRA, 2023. 1, 2, 3, 4, 6, 8, 9", + "[50] W. Luo, B. Yang, and R. Urtasun. Fast and furious: Real time end-to-end 3d detection, tracking and motion forecasting with a single convolutional net. In CVPR, 2018. 2", + "[51] Jiageng Mao, Yujing Xue, Minzhe Niu, Haoyue Bai, Jiashi Feng, Xiaodan Liang, Hang Xu, and Chunjing Xu. Voxel transformer for 3d object detection. In CVPR, 2021. 2", + "[52] Gellert Mattyus, Shenlong Wang, Sanja Fidler, and Raquel Urtasun. Hd maps: Fine-grained road segmentation by parsing ground and aerial images. In CVPR, 2016. 2", + "[53] Andrew Ng and Michael Jordan. On discriminative vs. generative classifiers: A comparison of logistic regression and naive bayes. In NeurIPS, 2001. 2", + "[54] Taesung Park, Jun-Yan Zhu, Oliver Wang, Jingwan Lu, Eli Shechtman, Alexei A. Efros, and Richard Zhang. Swapping autoencoder for deep image manipulation. In NeurIPS, 2020. 3", + "[55] Niki Parmar, Ashish Vaswani, Jakob Uszkoreit, Lukasz Kaiser, Noam Shazeer, Alexander Ku, and Dustin Tran. Image transformer. In ICML, 2018. 2", + "[56] Jonah Philion and Sanja Fidler. Lift, splat, shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3d. In ECCV, 2020. 1, 2, 3, 4, 6, 8" + ], + "bbox": [ + 78, + 90, + 470, + 900 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[57] Aditya Prakash, Kashyap Chitta, and Andreas Geiger. Multimodal fusion transformer for end-to-end autonomous driving. In CVPR, 2021. 2", + "[58] Marc'Aurelio Ranzato, Joshua Sussekind, Volodymyr Mnih, and Geoffrey Hinton. On deep generative models with applications to recognition. In CVPR, 2011. 2", + "[59] Cody Reading, Ali Harakeh, Julia Chae, and Steven L Waslander. Categorical depth distribution network for monocular 3d object detection. In CVPR, 2021. 2", + "[60] Thomas Roddick, Alex Kendall, and Roberto Cipolla. Orthographic feature transform for monocular 3d object detection. In BMVC, 2019. 2, 6, 8", + "[61] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In CVPR, 2022. 3", + "[62] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In MICCAI, 2015. 2", + "[63] S. Roth and M.J. Black. Fields of experts: a framework for learning image priors. In CVPR, 2005. 3", + "[64] Tim Salzmann, Boris Ivanovic, Punarjay Chakravarty, and Marco Pavone. Trajectory: Dynamically-feasible trajectory forecasting with heterogeneous data. In ECCV, 2020. 2", + "[65] Yuan Shen, Wei-Chiu Ma, and Shenlong Wang. SGAM: Building a virtual 3d world through simultaneous generation and mapping. In NeurIPS, 2022. 5", + "[66] Jianbo Shi and J. Malik. Normalized cuts and image segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 22(8):888-905, 2000. 3", + "[67] Shaoshuai Shi, Li Jiang, Jiajun Deng, Zhe Wang, Chaoxu Guo, Jianping Shi, Xiaogang Wang, and Hongsheng Li. Pvrccnn++: Point-voxel feature set abstraction with local vector representation for 3d object detection. Springer, 2023. 2", + "[68] Shaoshuai Shi, Xiaogang Wang, and Hongsheng Li. Pointr-cnn: 3d object proposal generation and detection from point cloud. In CVPR, 2019. 2", + "[69] Nitish Srivastava and Russ R Salakhutdinov. Multimodal learning with deep boltzmann machines. In NeurIPS, 2012. 2", + "[70] Deqing Sun, Stefan Roth, and Michael J. Black. Secrets of optical flow estimation and their principles. In CVPR, 2010. 3", + "[71] Sebastian Thrun, Mike Montemerlo, Hendrik Dahlkamp, David Stavens, Andrei Aron, James Diebel, Philip Fong, John Gale, Morgan Halpenny, Gabriel Hoffmann, Kenny Lau, Celia Oakley, Mark Palatucci, Vaughan Pratt, Pascal Stang, Sven Strohband, Cedric Dupont, Lars-Erik Jendrossek, Christian Koelen, Charles Markey, Carlo Rummel, Joe van Niekerk, Eric Jensen, Philippe Alessandrini, Gary Bradski, Bob Davies, Scott Ettinger, Adrian Kaehler, Ara Nefian, and Pamela Mahoney. Stanley: The Robot That Won the DARPA Grand Challenge. 2007. 2", + "[72] Hung-Yu Tseng, Lu Jiang, Ce Liu, Ming-Hsuan Yang, and Weilong Yang. Regularizing generative adversarial networks under limited data. In CVPR, 2021. 2", + "[73] Arash Vahdat and Jan Kautz. Nvae: A deep hierarchical variational autoencoder. In NeurIPS, 2020. 2" + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "8238", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[74] Aaron van den Oord, Oriol Vinyals, and Koray Kavukcuoglu. Neural discrete representation learning. In NeurIPS, 2017. 2", + "[75] Sourabh Vora, Alex H. Lang, Bassam Helou, and Oscar Bei-jbom. Pointpainting: Sequential fusion for 3d object detection. In CVPR, 2020. 2, 6, 8", + "[76] Enze Xie, Zhiding Yu, Daquan Zhou, Jonah Philion, Anima Anandkumar, Sanja Fidler, Ping Luo, and Jose M. Alvarez. $\\mathbf{M}^2$ bev: Multi-camera joint 3d detection and segmentation with unified birds-eye view representation. arXiv preprint arXiv:2204.05088, 2022. 2, 3", + "[77] Koichiro Yamaguchi, Tamir Hazan, David McAllester, and Raquel Urtasun. Continuous markov random fields for robust stereo estimation. In ECCV, 2012. 3", + "[78] Yan Yan, Yuxing Mao, and Bo Li. Second: Sparsely embedded convolutional detection. Sensors, 18(10), 2018. 4", + "[79] R. A. Yeh, C. Chen, T. Lim, A. G. Schwing, M. Hasegawa-Johnson, and M. N. Do. Semantic image inpainting with deep generative models. In CVPR, 2017. 2", + "[80] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Center-based 3d object detection and tracking. In CVPR, 2021. 1, 2, 3, 4, 6, 8, 9", + "[81] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Multi-modal virtual point 3d detection. In NeurIPS, 2021. 2, 3, 6, 8", + "[82] Wenyuan Zeng, Shenlong Wang, Renjie Liao, Yun Chen, Bin Yang, and Raquel Urtasun. Dsdnet: Deep structured self-driving network. In ECCV, 2020. 2", + "[83] Han Zhang, Ian Goodfellow, Dimitris Metaxas, and Augustus Odena. Self-attention generative adversarial networks. In ICML, 2019. 2", + "[84] Hang Zhao, Jiyang Gao, Tian Lan, Chen Sun, Benjamin Sapp, Balakrishnan Varadarajan, Yue Shen, Yi Shen, Yuning Chai, Cordelia Schmid, Congcong Li, and Dragomir Anguelov. Tnt: Target-driven trajectory prediction. In CoRL, 2020. 2", + "[85] Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, and Jiaya Jia. Pyramid scene parsing network. In CVPR, 2017. 2", + "[86] Shuai Zheng, Sadeep Jayasumana, Bernardino Romero-Paredes, Vibhav Vineet, Zhizhong Su, Dalong Du, Chang Huang, and Philip H. S. Torr. Conditional random fields as recurrent neural networks. In ICCV, 2015. 3", + "[87] Brady Zhou and Philipp Krahenbuhl. Cross-view transformers for real-time map-view semantic segmentation. In CVPR, 2022. 2", + "[88] Jun-Yan Zhu, Taesung Park, Phillip Isola, and Alexei A Efros. Unpaired image-to-image translation using cycle-consistent adversarial networks. In ICCV, 2017. 3", + "[89] Song Chun Zhu, Yingnian Wu, and D. Mumford. Frame: filters, random fields, and minimax entropy towards a unified theory for texture modeling. In CVPR, 1996. 3" + ], + "bbox": [ + 78, + 92, + 470, + 803 + ], + "page_idx": 11 + }, + { + "type": "page_number", + "text": "8239", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 11 + } +] \ No newline at end of file diff --git a/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/80d4c617-535f-4e51-ba9c-d279342878ed_model.json b/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/80d4c617-535f-4e51-ba9c-d279342878ed_model.json new file mode 100644 index 0000000000000000000000000000000000000000..8d424416aeec9492da6342d9a45b2989e501110e --- /dev/null +++ b/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/80d4c617-535f-4e51-ba9c-d279342878ed_model.json @@ -0,0 +1,3304 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.099, + 0.131, + 0.872, + 0.152 + ], + "angle": 0, + "content": "MapPrior: Bird's-Eye View Map Layout Estimation with Generative Models" + }, + { + "type": "text", + "bbox": [ + 0.213, + 0.18, + 0.756, + 0.219 + ], + "angle": 0, + "content": "Xiyue Zhu1 Vlas Zyrianov1 Zhijian Liu2 Shenlong Wang1 \n1University of Illinois at Urbana-Champaign 2MIT" + }, + { + "type": "text", + "bbox": [ + 0.355, + 0.235, + 0.614, + 0.252 + ], + "angle": 0, + "content": "https://mapprior.github.io" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.287, + 0.314, + 0.303 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.319, + 0.474, + 0.562 + ], + "angle": 0, + "content": "Despite tremendous advancements in bird's-eye view (BEV) perception, existing models fall short in generating realistic and coherent semantic map layouts, and they fail to account for uncertainties arising from partial sensor information (such as occlusion or limited coverage). In this work, we introduce MapPrior, a novel BEV perception framework that combines a traditional discriminative BEV perception model with a learned generative model for semantic map layouts. Our MapPrior delivers predictions with better accuracy, realism and uncertainty awareness. We evaluate our model on the large-scale nuScenes benchmark. At the time of submission, MapPrior outperforms the strongest competing method, with significantly improved MMD and ECE scores in camera- and LiDAR-based BEV perception. Furthermore, our method can be used to perpetually generate layouts with unconditional sampling." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.589, + 0.21, + 0.604 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.614, + 0.471, + 0.72 + ], + "angle": 0, + "content": "Accurately understanding the surrounding environment of autonomous vehicles is crucial to guarantee the safety of riders and other traffic participants. Among various perception approaches, Bird's-Eye View (BEV) perception has drawn significant attention in recent years thanks to its capacity to densely model scene layouts and its tight coupling with downstream planning [80, 56, 49]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.472, + 0.886 + ], + "angle": 0, + "content": "Existing perception models encounter two challenges. The first challenge pertains to the limitations of observations, particularly in distant or occluded regions, resulting in inaccurate predictions. This may manifest in choppy, out-of-distribution, or missing map elements. The second challenge is that most existing models do not consider uncertainty and diversity in possible road layouts. Taking Fig. 1 as an example, the state-of-the-art LiDAR perception model [80] generates incoherent lane markings and sidewalks with massive gaps and cannot quantify the uncertainty and multi-modality as it only produces a single prediction per input." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.886, + 0.47, + 0.902 + ], + "angle": 0, + "content": "This paper presents MapPrior, a novel BEV perception" + }, + { + "type": "image", + "bbox": [ + 0.507, + 0.286, + 0.891, + 0.495 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.504, + 0.896, + 0.61 + ], + "angle": 0, + "content": "Figure 1: Existing predictive BEV perception models do not provide realistic scene structures (e.g., the lane and sidewalks have gaps and are not straight). In contrast, our MapPrior is able to accurately recover the layout with a learned prior. These results are validated with a quantitative comparison, showing our method's superior accuracy, realism and uncertainty awareness." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.642, + 0.895, + 0.793 + ], + "angle": 0, + "content": "method that is accurate, realistic, and uncertainty-aware. At the heart of our method is a novel combination of the standard discriminative BEV perception model with a learned deep generative traffic layout prior. Incorporating generative modeling in this predictive task attempts to address the two aforementioned challenges – modeling the data distribution improves realism, and using a sampling process allows generating multiple realistic predictions. Combining our generative model with a discriminative perception model ensures that our method retains a strong predictive ability." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.896, + 0.901 + ], + "angle": 0, + "content": "Our approach comprises two steps, namely the prediction and generative steps. In the prediction step, we use an off-the-shelf BEV perception model [49] to make an initial layout estimate of the traffic scene from sensory input. In the generative step, we use our MapPrior model and initial estimate to sample one or multiple refined layouts. We perform sampling in a learned discrete latent space using a condi-" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8228" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.471, + 0.182 + ], + "angle": 0, + "content": "tional transformer that is provided with the initial prediction. Finally, the generated tokens are passed into a decoder to output the final layout prediction, which is diverse, realistic, and coherent with the input. The encoder, decoder, and codebook of the MapPrior are trained from real-world map data in an unsupervised way." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.183, + 0.471, + 0.334 + ], + "angle": 0, + "content": "We benchmark our method on the nuScenes dataset against various state-of-the-art BEV perception methods with varying modalities. Our results show that MapPrior outperforms existing methods in terms of accuracy (as reflected by mean intersection-over-union), realism (as reflected by maximum-mean discrepancy), and uncertainty awareness (as reflected by expected calibration error). Furthermore, we demonstrate the unconditional generation capabilities of MapPrior by generating a realistic and consistent HD map of a \\(30\\mathrm{km}\\)-long road." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.347, + 0.22, + 0.362 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.372, + 0.471, + 0.538 + ], + "angle": 0, + "content": "Self-driving perception aims to interpret sensory input and establish a representation of the surrounding environment from onboard sensors. It is a critical component for ensuring the safety and efficiency of autonomous vehicles, and various methods have been proposed to improve accuracy and robustness [71, 39]. Traditional approaches for self-driving perception involve multiple (isolated) subtasks, such as localizing against a pre-scanned environment [40, 4], object detection and tracking [38, 80, 68, 44, 50], image segmentation [62, 85, 10] and trajectory prediction [23, 64, 84, 43, 7, 82]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.539, + 0.471, + 0.674 + ], + "angle": 0, + "content": "Recently, there has been a growing interest in a unified Bird's Eye View (BEV) perception, both in academia [60, 87, 56, 76, 8, 50] and industry [26]. This approach aims to produce a top-down semantic layout of the traffic scene from sensory input, which is efficient, informative, and compact. Notably, the top-down layout is closely linked to downstream 2D motion planning for wheeled robots, making BEV perception particularly suitable for self-driving navigation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.675, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Various BEV perception modules have been studied in robotics and computer science to improve perception accuracy. These approaches typically take LiDAR [80, 38, 51, 67], multi-view camera [60, 87, 56, 76, 11, 46, 26, 59, 21], or both [81, 75, 49, 2, 57] as input, and output segmentations for road elements and detections for dynamic traffic participants like cars, cyclists or pedestrians. The majority of these methods are supervised and rely on predictive networks like CNNs [59, 67, 80, 38, 44, 60, 56] and transformers [2, 57, 11, 46, 51, 87, 21, 26, 27]. Despite their success, there are still unresolved challenges. For example, real-world traffic layouts are highly structured, with straight lane marks, strong topological relationships, and sharp road element boundaries. But such structures have proven difficult to preserve in the BEV perception output map, even" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.182 + ], + "angle": 0, + "content": "with state-of-the-art methods, as shown in Fig. 1. This can harm the realism of perception output and the practicality of the resulting map for motion planning. Additionally, most networks make a single layout estimation without diversity or calibrated uncertainty, leaving the autonomy vulnerable to catastrophic failure." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.183, + 0.895, + 0.333 + ], + "angle": 0, + "content": "HDMapNet [42], VectorMapNet [47], and others [52, 8] have been proposed to address the issue of layout structure by introducing a vectorized output map format with implicitly structured priors. However, this approach fails to account for all layer types and still produces significant artifacts in regions with limited observations. Very recently, calibrated confidence scores have been investigated to address the aforementioned uncertainty issue [37, 13], but the inherent multi-modal uncertainty in BEV perception remains under-explored." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.334, + 0.894, + 0.426 + ], + "angle": 0, + "content": "In contrast, our approach leverages generative modeling as a map prior, which encodes the rich structure of the traffic scene. Our conditional generative modeling also allows us to sample multiple diverse outputs for the same input. Consequently, our results are more accurate and realistic with better multi-modal uncertainty modeling." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.443, + 0.895, + 0.777 + ], + "angle": 0, + "content": "Generative models. Our approach to generative BEV perception involves learning a map prior and performing conditional sampling using deep generative models. Generative models learn to capture the underlying structure of the data distribution and create new, diverse samples. Several well-known approaches include VAEs (variational autoencoders) [34, 73], which use variational inference to learn a latent space model, and autoregressive models [55], which decompose the generation problem into simpler conditional generation tasks. GANs (generative adversarial networks) [20, 83, 1, 31, 28, 72, 5] use an adversarial loss to train networks to convert noise into samples. Flow-based models [33, 15] exploit an invertible process to sample from a proposal distribution. Recently, diffusion models [14, 24] have been developed that generate samples through a denoising-diffusion process. Our method leverages vector-quantized generative models [74, 18, 9], which use a discrete-valued latent space representation that is powerful, structure-preserving, and efficient for conditional sampling. Specifically, we build our map prior on top of this approach to capture the discrete structure of the map data and generate high-quality samples." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Generative approach for vision. Our approach belongs to the broader category of generative modeling approaches in computer vision [79, 53, 58, 69], which includes Markov random fields (MRFs), factor graphs, energy-based models, deep generative models, among others. These practices date back to the 1970s. In contrast to discriminative or predictive approaches, generative approaches often tackle the task" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8229" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.089, + 0.895, + 0.253 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.269, + 0.895, + 0.318 + ], + "angle": 0, + "content": "Figure 2: MapPrior first makes use of an off-the-shelf perception model to generate an initial noisy estimate from the sensory input. It then encodes the noisy estimate into a discrete latent code using a generative encoder and generates various samples through a transformer-based controlled synthesis. Finally, MapPrior decodes these samples into outputs with a decoder." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.341, + 0.475, + 0.508 + ], + "angle": 0, + "content": "as a marginal sampling or MAP inference problem, which is more effective at utilizing strong prior knowledge and modeling uncertainty. Representative works can be seen in low-level vision [19, 89], optical flow [70, 63], and image segmentation [66, 35, 86]. Generative approaches with conditional sampling have often been investigated in vision tasks involving multimodality or uncertainty, such as image editing [88, 28, 12, 54], image segmentation [41] and stereo estimation [16, 77]. However, few studies have explored their use in self-driving perception, despite its inherent multimodal uncertainty nature." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.523, + 0.188, + 0.54 + ], + "angle": 0, + "content": "3. Approach" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.549, + 0.473, + 0.716 + ], + "angle": 0, + "content": "The objective of this research is to develop a method that can generate a precise, realistic, and uncertainty-aware map layout from sensory input in one or a few modalities. To achieve this, we introduce a new framework named MapPrior that combines the predictive capability of discriminative models with the capacity of generative models to capture structures and uncertainties. We present a two-stage conditional sampling framework to explain our approach and detail the implementation of each module. Additionally, we discuss our design decisions, the learning process, and how our approach relates to previous methods." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.727, + 0.188, + 0.74 + ], + "angle": 0, + "content": "3.1. Overview" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.473, + 0.903 + ], + "angle": 0, + "content": "**Formulation.** We formulate the probabilistic BEV perception problem as a conditional sampling task. Given the sensory input \\(\\mathbf{x} \\in \\mathcal{X}\\) (which could be from a camera, LiDAR or multiple sensors), we aim to find one or multiple plausible traffic layouts \\(\\mathbf{y} \\in \\mathcal{Y}\\) from the top-down bird's-eye view. The traffic layout \\(\\mathbf{y}\\) is a multi-layer binary map centered at the ego vehicle. Conventional methods [49, 80, 56, 81, 76] rely on a deterministic predictive network \\(\\mathbf{y} = f_{\\theta}(\\mathbf{x})\\) to provide a single output estimation. We propose, instead, to use a generative vector-quantized latent space model to model" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.341, + 0.895, + 0.419 + ], + "angle": 0, + "content": "the uncertainty and diversity. Specifically, we aim to design a conditional probability model \\( p_{\\theta}(\\mathbf{y}|\\mathbf{x}) \\) that can sample our desired output \\( \\mathbf{y} \\) from a distribution. This allows us to explicitly model uncertainty and generate multiple plausible traffic layouts." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.441, + 0.897, + 0.669 + ], + "angle": 0, + "content": "Motivation. Intuitively speaking, the objective of a predictive perception model is to produce a coherent semantic layout that best represents the sensory input. However, this training objective does not necessarily optimize for structure preservation or realism. For example, minor defects in lane markers might not significantly affect cross-entropy, but could drastically impact downstream modules due to topological changes. On the other hand, a generative prior model, such as a GAN, is trained to capture realism in structures. The advantage of such a model is that it can be trained on HD map collections, without paired data, in an unsupervised manner. This insight inspires our proposed solution, which combines a predictive model with a generative model to tackle the conditional sampling task with both coherence and realism in mind." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.681, + 0.61, + 0.695 + ], + "angle": 0, + "content": "3.2. Inference" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.895, + 0.903 + ], + "angle": 0, + "content": "In our framework, the distribution \\( p_{\\theta}(\\mathbf{y}|\\mathbf{x}) \\) is defined implicitly using a latent model \\( \\mathbf{z} \\). The framework comprises of a predictive stage and a generative stage. During the predictive stage, the perception module \\( F(\\mathbf{x}) \\) generates an initial noisy estimate \\( \\mathbf{y}' \\) for input \\( \\mathbf{x} \\). For the generative stage, we take inspiration from recent successful techniques in vector-quantized generation [18, 9, 61] for conditional sampling and use a VQGAN-like model to generate multiple realistic samples. To achieve this, we encode the noisy estimate \\( \\mathbf{y}' \\) into a discrete latent code \\( \\mathbf{z}' \\) using a generative encoder \\( E(\\mathbf{y}') \\). This latent code \\( \\mathbf{z}' \\) and the sensory input \\( \\mathbf{x} \\) then guide the generative synthesis process through a transformer-based controlled synthesis in the latent space, producing various" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8230" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.09, + 0.472, + 0.152 + ], + "angle": 0, + "content": "samples \\(\\{\\mathbf{z}^{(k)}\\sim p(\\mathbf{z}|\\mathbf{z}',\\mathbf{x})\\}\\). Finally, these samples are decoded into multiple output samples using a decoder \\(G(\\cdot)\\): \\(\\mathbf{y}^{(k)} = G(\\mathbf{z}^{(k)})\\), which provides our final layout estimation samples. Fig. 2 depicts the overall inference framework." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.17, + 0.473, + 0.488 + ], + "angle": 0, + "content": "Predictive stage. The predictive stage aims to establish reliable initial layout estimation that can act as a guiding control during the conditional sampling stage. To achieve this, we have incorporated a predictive sensory backbone, VoxelNet [78, 80] for LiDAR and Swin Transformer [48] for multi-view camera inputs. The sensory backbone networks first extract features from the sensory space and then project them into bird's eye view features. For the LiDAR input, a 3D convolution backbone is utilized as a feature extractor, and the LiDAR features are flattened along the height dimension to project them to BEV. In contrast, for the camera input, a hierarchical transformer is used as a feature extractor for each view, and monocular depth estimation and view transformation are applied to project the features to BEV. The predictive model employs a convolutional segmentation head to generate the layout estimates, denoted by \\(\\mathbf{y}' = F(\\mathbf{x})\\). It should be noted that the resulting BEV map achieves a reasonable intersection-over-union score (IoU). However, as Fig. 1 highlights, the model suffers from unrealistic structures, missing road elements, and noise, particularly in regions with limited observations." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.506, + 0.472, + 0.641 + ], + "angle": 0, + "content": "Generative stage. To enhance the quality and diversity of our perception, we incorporate a generative map prior in the second stage for conditional generation. The generative map prior is built on a VQGAN architecture [18], which consists of three learnable components: the encoder \\( E \\), the decoder \\( G \\), and the codebook \\( \\mathcal{C} = \\{\\mathbf{c}_j\\} \\) with \\( j \\) being the code index. The encoder transforms a traffic layout into a latent feature map, where each element of the spatial map is chosen from one of the codes in the codebook as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.142, + 0.652, + 0.47, + 0.68 + ], + "angle": 0, + "content": "\\[\n\\mathbf {z} _ {t} (\\mathbf {y}) = \\underset {\\mathbf {c} _ {j} \\in \\mathcal {Z}} {\\arg \\max } \\| \\mathbf {c} _ {j} - E _ {t} (\\mathbf {y}) \\| _ {2} ^ {2}, \\quad \\forall t \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.69, + 0.47, + 0.796 + ], + "angle": 0, + "content": "where \\( t \\) is the \\( t \\)-th entry of the feature map \\( \\mathbf{z} \\). The decoder then transforms the latent code back to the layout map space: \\( G(\\mathbf{z}(\\mathbf{y})) \\). Sampling from this prior can be done by randomly drawing a latent code and decoding it into a layout map. The discrete-valued auto-encoder architecture greatly regularizes the output space in a structured manner, preventing it from producing unrealistic reconstructions, as shown in Fig 1." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.797, + 0.471, + 0.902 + ], + "angle": 0, + "content": "During conditional sampling at inference, we first encode the noisy estimate \\(\\mathbf{y}'\\) into a discrete latent code \\(\\mathbf{z}'\\) using a generative encoder \\(E\\). This latent code \\(\\mathbf{z}'\\) and the sensory input \\(\\mathbf{x}\\) are then used as guidance by a transformer \\(T(\\mathbf{z}',\\mathbf{x})\\) for the generative synthesis of the latent space, producing various samples \\(\\mathbf{z}^{(k)}\\sim p(\\mathbf{z}|\\mathbf{z}',\\mathbf{x}) = T(\\mathbf{z}',\\mathbf{x})\\). Specifically, we use an autoregressive scheme to progressively sample" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.09, + 0.892, + 0.171 + ], + "angle": 0, + "content": "each code, i.e. \\( p(\\mathbf{z}|\\mathbf{z}',\\mathbf{x}) = \\prod_{t}p(\\mathbf{z}_{t}|\\mathbf{z}_{< t}^{(k)},\\mathbf{z}',\\mathbf{x}) \\). At the \\( t \\)-th step, the transformer takes as input the current latent code \\( \\mathbf{z}_{< t} \\), the guidance code \\( \\mathbf{z}' \\) as well as encoded sensory feature \\( \\mathbf{x} \\) as input tokens, and outputs the next token's probability over the codebook \\( p(\\mathbf{z}_t|\\mathbf{z}_{< t}^{(k)},\\mathbf{z}',\\mathbf{x}) \\):" + }, + { + "type": "equation", + "bbox": [ + 0.617, + 0.182, + 0.892, + 0.202 + ], + "angle": 0, + "content": "\\[\n\\mathbf {z} _ {t} ^ {(k)} \\sim p \\left(\\mathbf {z} _ {t} \\mid \\mathbf {z} _ {< t} ^ {(k)}, \\mathbf {z} ^ {\\prime}, \\mathbf {x}\\right) \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.215, + 0.895, + 0.336 + ], + "angle": 0, + "content": "where \\(p(\\mathbf{z}_t|\\mathbf{z}_{< t}^{(k)},\\mathbf{z}',\\mathbf{x})\\) is the conditional probability estimated from the transformer. We use nucleus sampling [25] to get multiple diverse \\(\\mathbf{z}^{(k)}\\), which trades-off between sampling quality and diversity. Finally, these samples are decoded into multiple output samples using a decoder \\(G(\\cdot)\\): \\(\\mathbf{y}^{(k)} = G(\\mathbf{z}^{(k)})\\), which provides our final layout estimation samples. Formally speaking, the entire second stage can be written as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.555, + 0.348, + 0.892, + 0.366 + ], + "angle": 0, + "content": "\\[\n\\mathbf {y} ^ {(k)} = G \\left(\\mathbf {z} ^ {(k)}\\right) \\text {w h e r e} \\mathbf {z} ^ {(k)} \\sim p \\left(\\mathbf {z} \\mid \\mathbf {z} ^ {\\prime}, \\mathbf {x}\\right). \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.397, + 0.892, + 0.473 + ], + "angle": 0, + "content": "One-step generation. To enhance inference speed, we introduce a one-step variant of MapPrior, which generates a single sample rather than multiple diverse ones. It also produces tokens in a single step, bypassing the autoregressive sampling strategy:" + }, + { + "type": "equation", + "bbox": [ + 0.592, + 0.485, + 0.892, + 0.501 + ], + "angle": 0, + "content": "\\[\n\\mathbf {y} = G (\\mathbf {z}) \\text {w h e r e} \\mathbf {z} \\sim p (\\mathbf {z} | \\mathbf {x}). \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.513, + 0.894, + 0.543 + ], + "angle": 0, + "content": "This provides an effective way to trade off between the generation quality and efficiency." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.553, + 0.608, + 0.569 + ], + "angle": 0, + "content": "3.3. Learning" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.576, + 0.895, + 0.713 + ], + "angle": 0, + "content": "The training process consists of three individual components. Firstly, the perception module, denoted as \\( F \\), is learned to produce a reliable initial layout estimation. Secondly, the encoder, decoder, and codebook (denoted as \\( E \\), \\( G \\), and \\( C \\), respectively) are jointly trained to represent a strong map prior model. Lastly, given a fixed map prior model, the conditional sampling transformer \\( T \\) is learned to sample high-quality final results. In the following, we will provide a detailed description of each component's training procedure." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.731, + 0.894, + 0.822 + ], + "angle": 0, + "content": "Training the perception module. To train the perception module \\( F \\), we follow the standard practice adopted in prior works [49, 56] and employ a binary cross-entropy loss. The objective function is defined as follows: \\( \\min_F - [\\mathbf{y}_{\\mathrm{gt}}\\log \\mathbf{y}'] \\) where \\( \\mathbf{y}_{\\mathrm{gt}} \\) denotes the ground-truth label, and \\( \\mathbf{y}' = F(\\mathbf{x}) \\) is the corresponding prediction given the input \\( \\mathbf{x} \\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.894, + 0.901 + ], + "angle": 0, + "content": "Training the map prior model. The training procedure for the map prior model involves jointly optimizing the encoder \\( E \\), decoder \\( G \\), and the fixed-size codebook \\( C \\) in an end-to-end fashion. We use a vector-quantized auto-encoder" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "8231" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.079, + 0.088, + 0.199, + 0.194 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.207, + 0.087, + 0.351, + 0.193 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.358, + 0.087, + 0.621, + 0.193 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.63, + 0.089, + 0.892, + 0.193 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.204, + 0.894, + 0.234 + ], + "angle": 0, + "content": "Figure 3: MapPrior can be exploited in a progressive manner to generate perpetual traffic layouts. At each step, we choose a local area to sample to fill unexplored regions and expand the frontiers." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.261, + 0.471, + 0.292 + ], + "angle": 0, + "content": "to reconstruct the input data \\(\\mathbf{y}\\) through \\(\\hat{\\mathbf{y}} = G(\\mathbf{z}(\\mathbf{y}_i))\\) following Eq. 1. The following losses are minimized:" + }, + { + "type": "equation", + "bbox": [ + 0.129, + 0.301, + 0.471, + 0.323 + ], + "angle": 0, + "content": "\\[\n\\min _ {E, G, \\mathcal {C}} \\max _ {D} \\mathcal {L} _ {\\text {r e c o n}} + \\lambda_ {\\text {G A N}} \\mathcal {L} _ {\\text {G A N}} + \\mathcal {L} _ {\\text {l a t e n t}}. \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.331, + 0.47, + 0.376 + ], + "angle": 0, + "content": "The first term, \\(\\mathcal{L}_{\\mathrm{recon}}\\), is the reconstruction loss, which is designed to maximize the agreement between the input \\(\\mathbf{y}\\) and the reconstructed output:" + }, + { + "type": "equation", + "bbox": [ + 0.204, + 0.383, + 0.471, + 0.401 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {r e c o n}} = \\left\\| \\hat {\\mathbf {y}} - \\mathbf {y} \\right\\| ^ {2}. \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.409, + 0.471, + 0.528 + ], + "angle": 0, + "content": "In addition to the reconstruction loss, the second term is a GAN loss inspired by VQGAN [18] to encourage the reconstructed output to be realistic with a clear local structure and topology. A local discriminator \\( D(\\cdot) \\) is trained to differentiate between real and reconstructed BEV layout using cross-entropy loss, and the \\( \\mathcal{L}_{\\mathrm{GAN}} \\) loss aims to make the reconstructed image as realistic as possible through fooling the discriminator:" + }, + { + "type": "equation", + "bbox": [ + 0.147, + 0.538, + 0.47, + 0.556 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {G A N}} = \\log D (\\mathbf {y}) + \\log (1 - D (\\hat {\\mathbf {y}})), \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.563, + 0.47, + 0.594 + ], + "angle": 0, + "content": "where \\(\\mathbf{y}\\) is a real sample and \\(\\hat{\\mathbf{y}}\\) is a reconstructed sample. Following VQGAN [18], this loss is rescaled by" + }, + { + "type": "equation", + "bbox": [ + 0.186, + 0.602, + 0.47, + 0.62 + ], + "angle": 0, + "content": "\\[\n\\lambda_ {\\mathrm {G A N}} = g _ {\\mathrm {r e c}} / \\left(g _ {\\mathrm {G A N}} + \\sigma\\right), \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.627, + 0.469, + 0.656 + ], + "angle": 0, + "content": "where \\(g_{\\mathrm{rec}}\\) and \\(g_{\\mathrm{GAN}}\\) are gradients of \\(\\mathcal{L}_{\\mathrm{rec}}\\) and \\(\\mathcal{L}_{\\mathrm{GAN}}\\) with respect to the last layer of the generator." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.657, + 0.47, + 0.716 + ], + "angle": 0, + "content": "The last term promotes the expressiveness of the codebook. We expect the latent feature \\( E(\\mathbf{y}) \\) to be close to its nearest codebook token and vice versa. Thus, the latent loss is defined as" + }, + { + "type": "equation", + "bbox": [ + 0.113, + 0.725, + 0.47, + 0.743 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {l a t e n t}} = \\left\\| \\mathbf {z} - \\operatorname {s g} [ E (\\mathbf {y}) ] \\right\\| ^ {2} + \\left\\| \\operatorname {s g} [ \\mathbf {z} ] - E (\\mathbf {y}) \\right\\| ^ {2}, \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.75, + 0.347, + 0.767 + ], + "angle": 0, + "content": "where \\(\\mathrm{sg}[\\cdot ]\\) is a gradient detach operator." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.783, + 0.471, + 0.874 + ], + "angle": 0, + "content": "Training the conditional sampler. Our conditional sampling transformer, denoted as \\( T \\), is trained in the latent code space to sample high-likelihood latent codes given input controlling guidance. Given a paired input and output \\( (\\mathbf{x},\\mathbf{y}) \\) and fixed perception module \\( F \\), map prior model \\( E,G,C \\), the transformer is trained using the following objective:" + }, + { + "type": "equation", + "bbox": [ + 0.212, + 0.883, + 0.47, + 0.905 + ], + "angle": 0, + "content": "\\[\n\\min _ {T} \\mathcal {L} _ {\\mathrm {C E}} + \\mathcal {L} _ {\\text {o u t}}. \\tag {10}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.261, + 0.894, + 0.337 + ], + "angle": 0, + "content": "The first loss, \\(\\mathcal{L}_{\\mathrm{CE}}\\), optimizes the transformer to maximize the estimated probability of the latent code of the ground-truth layout. We use a cross-entropy loss between the transformer's estimated probability \\(T(\\mathbf{z}',\\mathbf{x})\\) and the ground-truth sample \\(\\mathbf{y}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.58, + 0.348, + 0.893, + 0.379 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {C E}} = \\sum_ {t} \\sum_ {i} \\mathbf {y} _ {i, t} \\log T _ {i, t} \\left(\\mathbf {z} ^ {\\prime}, \\mathbf {x}\\right), \\tag {11}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.389, + 0.892, + 0.418 + ], + "angle": 0, + "content": "where, \\( i \\) represents the \\( i \\)-th output label, and \\( t \\) represents the \\( t \\)-th autoregressive step." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.419, + 0.893, + 0.523 + ], + "angle": 0, + "content": "Although making the latent code closer to the ground-truth map's latent code is essential, it is not sufficient to ensure high output fidelity. Hence, we include an additional reconstruction output loss that encourages the transformer to favor samples that produce high-accuracy layouts. Similar to the reconstruction loss in auto-encoding training, an L2 reconstruction loss is used:" + }, + { + "type": "equation", + "bbox": [ + 0.633, + 0.535, + 0.893, + 0.553 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {o u t}} = \\left\\| \\mathbf {y} - \\hat {\\mathbf {y}} \\right\\| _ {2} ^ {2}, \\tag {12}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.564, + 0.894, + 0.624 + ], + "angle": 0, + "content": "where \\(\\mathbf{y}\\) is the true map and \\(\\hat{\\mathbf{y}}\\) is the predicted map. Note that codebook selection in latent code space is non-differentiable; thus, we use Gumbel-Softmax [29] to ensure differentiability in practice throughout the training processes." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.633, + 0.625, + 0.647 + ], + "angle": 0, + "content": "3.4. Discussions" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.656, + 0.894, + 0.746 + ], + "angle": 0, + "content": "Uncertainty quantification. Our latent transformer offers diverse results \\(\\mathbf{y}^{(k)}\\) by using a conditional sampling scheme. By estimating the variance of \\(\\mathbf{y}^{(k)}\\), we can estimate the uncertainty map for our results. By using the average of \\(\\mathbf{y}^{(k)}\\), we aggregate the diverse result samples to a more stable and better calibrated results." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.895, + 0.902 + ], + "angle": 0, + "content": "Perpetual layout generation. Our trained map prior enables the continuous generation of realistic and varied driving sequences, which are extremely valuable for content creation and autonomous driving simulations. We use a progressive generation strategy, which builds upon prior works [3, 17, 45, 65, 18, 9]. The strategy involves iteratively expanding our visual horizon and generating new content by leveraging our map prior model to fill in the previously unseen areas. We illustrate this process in Fig. 3." + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8232" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.089, + 0.895, + 0.121 + ], + "angle": 0, + "content": "Table 1: Quantitative results of BEV map segmentation on nuScenes. Our MapPrior achieves better accuracy (IoU), realism (MMD) and uncertainty awareness (ECE) than discriminative BEV perception baselines." + }, + { + "type": "table", + "bbox": [ + 0.081, + 0.131, + 0.892, + 0.389 + ], + "angle": 0, + "content": "
ModalityIoU (↑)MMD (↓)ECE (↓)
DrivablePed. XWalkwayStop LineCarparkDividerMean
OFT [60]C74.035.345.927.535.933.942.154.50.045
LSS [56]C75.438.846.330.339.136.544.443.20.041
BEVFusion-C [49]C81.754.858.447.450.746.456.639.60.038
MapPrior-CC81.754.658.346.753.345.156.728.40.026
MapPrior-C (1 step)C81.654.658.446.853.945.156.728.7-
PointPillars [38]L72.043.153.129.727.737.543.8153.00.111
BEVFusion-L [80, 49]L75.648.457.536.531.741.948.6115.20.090
MapPrior-LL81.049.758.037.538.242.451.135.80.038
MapPrior-L (1 step)L80.149.057.837.833.042.550.050.2-
PointPainting [75]C+L75.948.557.136.924.541.949.1109.80.099
MVP [81]C+L76.148.757.036.933.042.249.0115.30.096
BEVFusion [49]C+L85.560.567.652.057.053.762.721.60.038
MapPrior-CLC+L85.361.467.151.760.053.363.128.00.020
MapPrior-CL (1 step)C+L85.361.367.051.759.653.163.028.1-
" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.426, + 0.21, + 0.444 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.452, + 0.474, + 0.619 + ], + "angle": 0, + "content": "We evaluate our MapPrior on BEV map segmentation and generation tasks for both LiDAR and camera modalities. We evaluate our approach to generate an accurate and realistic traffic layout both quantitatively and qualitatively in Sec. 4.2. We show how output loss and BEV features can affect our performance in Tab. 2. We finally estimate how our model can generate diverse samples and how our model is calibrated using the diverse samples in Fig. 5 and 6. Specifically, we are interested in seeing how using a generative prior affects accuracy (reflected by mIoU), realism (reflected by MMD), and model calibration (reflected by ECE)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.629, + 0.269, + 0.646 + ], + "angle": 0, + "content": "4.1. Experimental Setup" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.653, + 0.472, + 0.851 + ], + "angle": 0, + "content": "Datasets. We evaluate our model on nuScenes [6], a large-scale outdoor autonomous driving dataset containing 1000 driving scenes, consisting of 700 scenes for training, 150 for validation, and 150 scenes for testing. It has around 40,000 annotated key-frames, each with six monocular camera images encompassing a 360-degree FoV (used by camera models), and a 32-beam LiDAR scan (used by LiDAR models). We follow the train/validation split provided by nuScenes. We evaluate all models on the validation set following common practices in BEV layout estimation [49, 56]. The ground truth segmentation map is provided by nuScenes and was labeled manually [6]. We rasterized the map layers from the nuScenes map into the ego frame." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.871, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Metrics. We provide quantitative results for both segmentation and generative tasks. For BEV map segmentation," + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.428, + 0.895, + 0.563 + ], + "angle": 0, + "content": "our metric is the Intersection-over-Union (IoU score) for six map classes (drivable area, pedestrian crossing, walkway, stop line, car-parking area, and lane divider), as well as the mean IoU averaged over all six map classes. Since different classes may overlap, we separately compare the IoU score for each class. For all baseline predictive models, we choose the best threshold that maximizes IoU for comparison to ensure no bias is introduced due to the suboptimal threshold selection. For MapPrior, we simply use 0.5 as the threshold." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.564, + 0.895, + 0.64 + ], + "angle": 0, + "content": "To evaluate generated map layout realism, we use the maximum mean discrepancy (MMD) metric. MMD effectively measures the distance between two distributions of two sets of samples by measuring the squared difference of their mean in different spaces:" + }, + { + "type": "equation", + "bbox": [ + 0.505, + 0.648, + 0.892, + 0.746 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathrm {M M D} = \\sum_ {i} ^ {n} \\sum_ {i ^ {\\prime}} ^ {n} k (\\mathbf {x} _ {i}, \\mathbf {x} _ {i ^ {\\prime}}) / n ^ {2} + \\sum_ {j} ^ {m} \\sum_ {j ^ {\\prime}} ^ {m} k (\\mathbf {x} _ {j}, \\mathbf {x} _ {j ^ {\\prime}}) / m ^ {2} \\\\ - 2 \\cdot \\sum_ {i} ^ {n} \\sum_ {j} ^ {m} k \\left(\\mathbf {x} _ {i}, \\mathbf {x} _ {j}\\right) / n m. \\tag {13} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.747, + 0.892, + 0.776 + ], + "angle": 0, + "content": "To evaluate a set of predicted layouts, we compare it with a set of ground truth layouts from nuScenes." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.777, + 0.895, + 0.853 + ], + "angle": 0, + "content": "To evaluate uncertainty in our diversity results, we use Expected Calibration Error (ECE) [36, 22]. ECE compares output probabilities to model accuracy. It splits the results into several bins and measures a weighted average discrepancy between accuracy and confidence within each bin:" + }, + { + "type": "equation", + "bbox": [ + 0.571, + 0.862, + 0.895, + 0.904 + ], + "angle": 0, + "content": "\\[\n\\mathrm {E C E} = \\sum_ {b} ^ {B} n _ {b} | \\operatorname {a c c} (b) - \\operatorname {c o n f} (b) | / n, \\tag {14}\n\\]" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8233" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.092, + 0.088, + 0.198, + 0.249 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.126, + 0.252, + 0.164, + 0.262 + ], + "angle": 0, + "content": "LiDAR" + }, + { + "type": "image", + "bbox": [ + 0.214, + 0.089, + 0.371, + 0.249 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.259, + 0.252, + 0.326, + 0.262 + ], + "angle": 0, + "content": "PointPillars" + }, + { + "type": "image", + "bbox": [ + 0.387, + 0.089, + 0.543, + 0.25 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.427, + 0.252, + 0.503, + 0.262 + ], + "angle": 0, + "content": "BEVFusion-L" + }, + { + "type": "image", + "bbox": [ + 0.56, + 0.089, + 0.715, + 0.25 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.587, + 0.252, + 0.687, + 0.264 + ], + "angle": 0, + "content": "MapPrior-L (Ours)" + }, + { + "type": "image", + "bbox": [ + 0.734, + 0.089, + 0.887, + 0.25 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.771, + 0.252, + 0.848, + 0.263 + ], + "angle": 0, + "content": "Ground Truth" + }, + { + "type": "image", + "bbox": [ + 0.092, + 0.286, + 0.198, + 0.34 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.121, + 0.353, + 0.168, + 0.364 + ], + "angle": 0, + "content": "Camera" + }, + { + "type": "image", + "bbox": [ + 0.216, + 0.27, + 0.371, + 0.351 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.279, + 0.353, + 0.305, + 0.363 + ], + "angle": 0, + "content": "LSS" + }, + { + "type": "image", + "bbox": [ + 0.387, + 0.271, + 0.543, + 0.351 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.426, + 0.353, + 0.503, + 0.364 + ], + "angle": 0, + "content": "BEVFusion-C" + }, + { + "type": "image", + "bbox": [ + 0.56, + 0.271, + 0.715, + 0.351 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.586, + 0.353, + 0.688, + 0.365 + ], + "angle": 0, + "content": "MapPrior-C (Ours)" + }, + { + "type": "image", + "bbox": [ + 0.734, + 0.271, + 0.888, + 0.351 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.771, + 0.353, + 0.848, + 0.364 + ], + "angle": 0, + "content": "Ground Truth" + }, + { + "type": "image", + "bbox": [ + 0.093, + 0.374, + 0.195, + 0.452 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.124, + 0.458, + 0.162, + 0.469 + ], + "angle": 0, + "content": "LiDAR" + }, + { + "type": "image", + "bbox": [ + 0.223, + 0.383, + 0.348, + 0.443 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.261, + 0.459, + 0.306, + 0.47 + ], + "angle": 0, + "content": "Camera" + }, + { + "type": "image", + "bbox": [ + 0.389, + 0.371, + 0.543, + 0.45 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.426, + 0.456, + 0.512, + 0.467 + ], + "angle": 0, + "content": "BEVFusion-CL" + }, + { + "type": "image", + "bbox": [ + 0.565, + 0.371, + 0.718, + 0.45 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.587, + 0.456, + 0.696, + 0.468 + ], + "angle": 0, + "content": "MapPrior-CL (Ours)" + }, + { + "type": "image", + "bbox": [ + 0.739, + 0.37, + 0.893, + 0.45 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.773, + 0.457, + 0.851, + 0.468 + ], + "angle": 0, + "content": "Ground Truth" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.49, + 0.893, + 0.536 + ], + "angle": 0, + "content": "Figure 4: Qualitative results of BEV map segmentation on nuScenes. Discriminative BEV perception baselines produce results with clear artifacts (e.g., lane markings are discontinuous, roads and pedestrian walkways have unrealistic gaps, etc.). In contrast, our MapPrior produces semantic map layouts that are clean, realistic, and in-distribution." + }, + { + "type": "image", + "bbox": [ + 0.088, + 0.549, + 0.212, + 0.644 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.088, + 0.646, + 0.211, + 0.739 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.131, + 0.742, + 0.168, + 0.756 + ], + "angle": 0, + "content": "Input" + }, + { + "type": "image", + "bbox": [ + 0.224, + 0.571, + 0.349, + 0.63 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.225, + 0.643, + 0.35, + 0.74 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.274, + 0.742, + 0.299, + 0.754 + ], + "angle": 0, + "content": "GT" + }, + { + "type": "image", + "bbox": [ + 0.361, + 0.571, + 0.485, + 0.63 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.361, + 0.644, + 0.486, + 0.739 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.376, + 0.742, + 0.468, + 0.756 + ], + "angle": 0, + "content": "Our Sample 1" + }, + { + "type": "image", + "bbox": [ + 0.498, + 0.57, + 0.622, + 0.63 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.498, + 0.644, + 0.622, + 0.739 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.513, + 0.742, + 0.607, + 0.756 + ], + "angle": 0, + "content": "Our Sample 2" + }, + { + "type": "image", + "bbox": [ + 0.635, + 0.57, + 0.758, + 0.631 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.636, + 0.644, + 0.758, + 0.739 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.65, + 0.742, + 0.743, + 0.756 + ], + "angle": 0, + "content": "Our Sample 3" + }, + { + "type": "image", + "bbox": [ + 0.773, + 0.55, + 0.895, + 0.644 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.773, + 0.645, + 0.895, + 0.739 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.777, + 0.742, + 0.89, + 0.756 + ], + "angle": 0, + "content": "Uncertainty Map" + }, + { + "type": "image_caption", + "bbox": [ + 0.304, + 0.769, + 0.663, + 0.784 + ], + "angle": 0, + "content": "Figure 5: Qualitative results of diversity on NuScenes." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.471, + 0.887 + ], + "angle": 0, + "content": "where acc is the empirical accuracy, and conf is the estimated confidence for each bin, \\( n_b \\) is the # of samples per each bin and \\( n \\) is the total # of samples. ECE is an important metric in BEV map segmentation, as ignoring uncertainties can lead to bad consequences in driving planning. We gener" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.811, + 0.894, + 0.871 + ], + "angle": 0, + "content": "ate 15 diverse outputs for every instance and use the mean as the confidence. The baseline model is trained end-to-end with cross-entropy loss, so the predictions produced by the softmax function are assumed to be the pseudo probabilities." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8234" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.088, + 0.088, + 0.191, + 0.247 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.113, + 0.261, + 0.165, + 0.274 + ], + "angle": 0, + "content": "LiDAR" + }, + { + "type": "image", + "bbox": [ + 0.203, + 0.088, + 0.307, + 0.246 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.221, + 0.249, + 0.292, + 0.262 + ], + "angle": 0, + "content": "Prediction" + }, + { + "type": "image", + "bbox": [ + 0.321, + 0.088, + 0.424, + 0.246 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.334, + 0.249, + 0.411, + 0.263 + ], + "angle": 0, + "content": "Uncertainty" + }, + { + "type": "image", + "bbox": [ + 0.439, + 0.088, + 0.541, + 0.246 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.453, + 0.249, + 0.526, + 0.264 + ], + "angle": 0, + "content": "Error Map" + }, + { + "type": "image", + "bbox": [ + 0.554, + 0.088, + 0.657, + 0.246 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.571, + 0.249, + 0.641, + 0.263 + ], + "angle": 0, + "content": "Prediction" + }, + { + "type": "image", + "bbox": [ + 0.671, + 0.088, + 0.774, + 0.246 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.683, + 0.249, + 0.762, + 0.264 + ], + "angle": 0, + "content": "Uncertainty" + }, + { + "type": "image", + "bbox": [ + 0.789, + 0.088, + 0.891, + 0.246 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.803, + 0.249, + 0.875, + 0.264 + ], + "angle": 0, + "content": "Error Map" + }, + { + "type": "image_caption", + "bbox": [ + 0.324, + 0.27, + 0.422, + 0.284 + ], + "angle": 0, + "content": "BEVFusion-C" + }, + { + "type": "image_caption", + "bbox": [ + 0.689, + 0.27, + 0.756, + 0.285 + ], + "angle": 0, + "content": "MapPrior" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.298, + 0.895, + 0.359 + ], + "angle": 0, + "content": "Figure 6: Prediction, uncertainty, and error map comparison between BEVFusion-C and MapPrior. BEVFusion generates a misguided uncertainty boundary by giving high weight to areas where map elements are unlikely to be. In comparison, MapPrior's uncertainty is constrained to map element boundaries. This is further confirmed with the error map, where MapPrior's uncertainty map closely matches the error map." + }, + { + "type": "table_caption", + "bbox": [ + 0.099, + 0.383, + 0.447, + 0.399 + ], + "angle": 0, + "content": "Table 2: Ablation studies for MapPrior on nuScenes." + }, + { + "type": "table", + "bbox": [ + 0.085, + 0.41, + 0.462, + 0.482 + ], + "angle": 0, + "content": "
Output Loss LoutT(z') or T(z', x)mIoU (↑)MMD (↓)
-T(z')45.633.3
✓T(z')49.045.6
✓T(z', x)51.135.8
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.521, + 0.471, + 0.581 + ], + "angle": 0, + "content": "Baselines. For LiDAR-only segmentation, we use Point-Pillars [38], and BEVFusion-L [49, 80] as our baselines. To the best of our knowledge, BEVFusion-L is the current state-of-the-art method in LiDAR-based BEV map segmentation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.581, + 0.47, + 0.673 + ], + "angle": 0, + "content": "For camera-only segmentation, our baseline model are LSS [56], OFT [60], and BEVFusion-C [49]. Among them, BEVFusion-C is the current state-of-the-art model with a significantly higher IoU score than other methods. We use open-source code from BEVFusion. We also provide results of multi-modal models [49, 75, 81] for reference." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.689, + 0.471, + 0.84 + ], + "angle": 0, + "content": "Implementation details. Following [49], we perform segmentation in a \\([-50\\mathrm{m}, 50\\mathrm{m}] \\times [-50\\mathrm{m}, 50\\mathrm{m}]\\) region around the ego car with a resolution of 0.5 meters/pixel, resulting in a final image size of \\(200 \\times 200\\). Since map classes may overlap, our model performs binary segmentation for all classes. The encoder and decoder comprise four downsampling and four upsampling blocks processing a series of 128-256-512-256-128 channels. Each block comprises 2 reset blocks and one convolution and uses sigmoid activation and GroupNorm. The resolution of the latent space is [12,12]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.471, + 0.902 + ], + "angle": 0, + "content": "For the generative step, we train a minGPT [30] transformer conditioned on the generated sequence, extracted BEV features, and the initial noisy map. We train the whole model using Adam [32] with a learning rate of 9.0e-6. The" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.385, + 0.895, + 0.476 + ], + "angle": 0, + "content": "transformer's BEV feature encoder for the transformer has a similar structure to the model encoder consisting of 3 down-sampling blocks. The BEV feature encoder converts the original BEV features shaped [128, 128] into latent space tokens shaped [12, 12]. We apply a multiplier of 100 on the output loss to balance the magnitude of different losses." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.483, + 0.795, + 0.499 + ], + "angle": 0, + "content": "4.2. Map Segmentation as Generation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.506, + 0.895, + 0.746 + ], + "angle": 0, + "content": "Quantitative results. We show our quantitative results for map segmentation in Tab. 1. The results show that MapPrior achieves state-of-the-art performance. Comparing with BEVFusion-L, our MapPrior-L offers \\(2.5\\%\\) improvement in mIoU, which is brought purely by our proposed generative stage. Furthermore, MapPrior provides a substantial improvement in the MMD score compared to baselines. MMD is a metric of distance between the generated layout predictions and the ground truth distribution. This shows that MapPrior's outputs closely match the ground truth data distribution. In addition, this stark difference in MapPrior's MMD performance compared to the baselines implies that the realism metric and precision metric are not closely coupled. It is possible to achieve higher IoU while generating non-realistic samples, or vice versa. Our approach simultaneously pushes the limit of the two." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.748, + 0.895, + 0.854 + ], + "angle": 0, + "content": "Moreover, inference speed is vital for MapPrior. Using an RTX A6000 GPU, we compared the inference speeds of our model and BEVFusion in terms of frames per second (FPS). Our findings are presented in Tab. 3. These results indicate that one-step MapPrior is significantly closer to real-time performance compared to the standard MapPrior, with only a minor trade-off in IoU for increased uncertainty awareness." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.895, + 0.902 + ], + "angle": 0, + "content": "Qualitative results. We show our qualitative results in Fig. 4. Compared to other methods, MapPrior can consist" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8235" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.139, + 0.086, + 0.833, + 0.215 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.175, + 0.224, + 0.794, + 0.24 + ], + "angle": 0, + "content": "Figure 7: Results for perpetual traffic scene generation. Two road subsections are shown here." + }, + { + "type": "table_caption", + "bbox": [ + 0.127, + 0.254, + 0.419, + 0.27 + ], + "angle": 0, + "content": "Table 3: Performance of one-step MapPrior." + }, + { + "type": "table", + "bbox": [ + 0.08, + 0.28, + 0.472, + 0.449 + ], + "angle": 0, + "content": "
ModalitymIoU (↑)MMD (↓)FPS
BEVFusion-C [49]C56.639.68.85
MapPrior-CC56.728.40.60
MapPrior-C (1 step)C56.728.74.26
BEVFusion-L [80, 49]L48.6115.27.52
MapPrior-LL51.135.80.57
MapPrior-L (1 step)L50.050.24.88
BEVFusion [49]C+L62.721.65.52
MapPrior-CLC+L63.128.00.55
MapPrior-CL (1 step)C+L63.028.13.61
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.474, + 0.47, + 0.624 + ], + "angle": 0, + "content": "tently generate coherent and realistic class predictions within the entire map region. Our model has a more coherent divider layout, whereas the baseline methods usually have broken/missing lane dividers. In the baseline methods, the stopline is often jagged and appears disconnected from the road. In distant areas from the ego car, our model tries to make a plausible layout estimate when other methods fail due to limited observations (this is especially noticeable in the pedestrian walkways). The edges from our method are also more smooth, resulting in a more realistic estimation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.649, + 0.47, + 0.709 + ], + "angle": 0, + "content": "Diversity and uncertainty calibration. We show that our model can produce a better-calibrated layout with diversity. In Fig. 5, we show that our model can generate multiple diverse and feasible layouts, All of which are realistic." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.71, + 0.47, + 0.802 + ], + "angle": 0, + "content": "By aggregating the diverse samples, our model can produce a calibrated uncertainty map. We show our results in Fig. 6. Compared to the baselines (which are unable to generate multiple samples), our uncertainty map aligns with the error map much more accurately. ECE scores in Tab. 1 further validate this quantitatively." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.826, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Perpetual generation. We show our qualitative results for generating 'infinite' roads in Fig. 7. We have generated a single \\(30\\mathrm{km}\\) long road. Due to size constraints, we are only able to show a subsection. The generated traffic scene contains a highway with intermittent intersections resembling a" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.256, + 0.892, + 0.287 + ], + "angle": 0, + "content": "road layout in a city. We provide the entire road as a gif in our supplementary materials." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.293, + 0.625, + 0.308 + ], + "angle": 0, + "content": "4.3. Discussions" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.317, + 0.895, + 0.438 + ], + "angle": 0, + "content": "Ablation studies. To justify our design, we provide ablation studies in Tab. 2. L2 loss at the output end changes the model's optimization target. It puts more weight on generating accurate results as opposed to generating i.i.d. data. Therefore, the model achieves a higher IoU score at the cost of a slightly worse MMD. Providing the transformer with BEV features boosts the performance by around \\(3\\%\\) in the IoU score, and decreases MMD by around \\(21\\%\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.455, + 0.895, + 0.651 + ], + "angle": 0, + "content": "Inference speed. Inference speed is essential for MapPrior, especially given the real-time demands of autonomous driving. While transformers offer remarkable generative abilities, they inherently slow down performance due to their sequential token generation process. Moreover, the need for MapPrior to produce diverse outcomes further curtails its inference speed. To address this, we introduced the one-step variant of MapPrior, which predicts a single sample for each input and generates all tokens simultaneously. As evidenced in Tab. 3, the one-step MapPrior registers a marginally worse MMD score and falls short in uncertainty awareness. Nonetheless, the one-step MapPrior markedly outpaces the standard MapPrior in speed." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.662, + 0.619, + 0.677 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.687, + 0.895, + 0.809 + ], + "angle": 0, + "content": "This paper presents MapPrior, a novel generative method for performing BEV perception. The core idea is to leverage a learned generative prior over traffic layouts to provide diverse and accurate layout estimations, which potentially enable more informed decision-making and motion planning. Our experiments show that our approach produces more realistic scene layouts, enhances accuracy, and better calibrates uncertainty compared to current methods." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Acknowledgement. The project is partially funded by the Illinois Smart Transportation Initiative STII-21-07, an Amazon Research Award, an Intel Research Gift, and an IBM IIDAI grant. We also thank NVIDIA for the Academic Hardware Grant. VZ is supported by the Frontier Fellowship." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8236" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.175, + 0.107 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.471, + 0.143 + ], + "angle": 0, + "content": "[1] Martin Arjovsky, Soumith Chintala, and Léon Bottou. Wasserstein generative adversarial networks. In ICML, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.146, + 0.472, + 0.2 + ], + "angle": 0, + "content": "[2] Xuyang Bai, Zeyu Hu, Xinge Zhu, Qingqiu Huang, Yilun Chen, Hongbo Fu, and Chiew-Lan Tai. Transfusion: Robust lidar-camera fusion for 3d object detection with transformers. In CVPR, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.203, + 0.471, + 0.245 + ], + "angle": 0, + "content": "[3] Connelly Barnes, Eli Shechtman, Adam Finkelstein, and Dan B Goldman. PatchMatch: A randomized correspondence algorithm for structural image editing. 2009. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.247, + 0.47, + 0.288 + ], + "angle": 0, + "content": "[4] Ioan Andrei Barsan, Shenlong Wang, Andrei Pokrovsky, and Raquel Urtasun. Learning to localize using a lidar intensity map. In CoRL, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.291, + 0.47, + 0.331 + ], + "angle": 0, + "content": "[5] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. In ICLR, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.334, + 0.471, + 0.389 + ], + "angle": 0, + "content": "[6] Holger Caesar, Varun Bankiti, Alex H. Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In CVPR, 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.391, + 0.471, + 0.432 + ], + "angle": 0, + "content": "[7] Sergio Casas, Wenjie Luo, and Raquel Urtasun. Intentnet: Learning to predict intention from raw sensor data. In CoRL, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.435, + 0.471, + 0.475 + ], + "angle": 0, + "content": "[8] Sergio Casas, Abbas Sadat, and Raquel Urtasun. Mp3: A unified model to map, perceive, predict and plan. In CVPR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.479, + 0.471, + 0.52 + ], + "angle": 0, + "content": "[9] Huiwen Chang, Han Zhang, Lu Jiang, Ce Liu, and William T. Freeman. Maskgit: Masked generative image transformer. In CVPR, 2022. 2, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.523, + 0.471, + 0.564 + ], + "angle": 0, + "content": "[10] Bowen Cheng, Alexander G. Schwing, and Alexander Kirillov. Per-pixel classification is not all you need for semantic segmentation. In NeurIPS, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.567, + 0.471, + 0.607 + ], + "angle": 0, + "content": "[11] Kashyap Chitta, Aditya Prakash, and Andreas Geiger. Neat: Neural attention fields for end-to-end autonomous driving. In CVPR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.61, + 0.471, + 0.637 + ], + "angle": 0, + "content": "[12] Min Jin Chong and David Forsyth. Jojogan: One shot face stylization. In ECCV, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.64, + 0.471, + 0.681 + ], + "angle": 0, + "content": "[13] Laurene Claussmann, Marc Revilloud, Dominique Gruyer, and Sébastien Glaser. A review of motion planning for highway autonomous driving. 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.683, + 0.471, + 0.71 + ], + "angle": 0, + "content": "[14] Prafulla Dhariwal and Alex Nichol. Diffusion models beat gans on image synthesis. In NeurIPS, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.713, + 0.471, + 0.753 + ], + "angle": 0, + "content": "[15] Laurent Dinh, David Krueger, and Yoshua Bengio. Nice: Non-linear independent components estimation. In ICLR (Workshop), 2014. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.756, + 0.471, + 0.797 + ], + "angle": 0, + "content": "[16] Shivam Duggal, Shenlong Wang, Wei-Chiu Ma, Rui Hu, and Raquel Urtasun. Deepruner: Learning efficient stereo matching via differentiable patchmatch. In ICCV, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.8, + 0.471, + 0.828 + ], + "angle": 0, + "content": "[17] Alexei A. Efros and William T. Freeman. Image quilting for texture synthesis and transfer. In SIGGRAPH, 2001. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.83, + 0.471, + 0.87 + ], + "angle": 0, + "content": "[18] Patrick Esser, Robin Rombach, and Björn Ommer. Taming transformers for high-resolution image synthesis. In CVPR, 2021. 2, 3, 4, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.471, + 0.9 + ], + "angle": 0, + "content": "[19] W.T. Freeman and E.C. Pasztor. Learning low-level vision. In CVPR, 1999. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.472, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.147 + ], + "angle": 0, + "content": "[20] Ian J. Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. In NeurIPS, 2014. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.149, + 0.894, + 0.176 + ], + "angle": 0, + "content": "[21] Nikhil Gosala and Abhinav Valada. Bird's-eye-view panoptic segmentation using monocular frontal view images. 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.179, + 0.894, + 0.204 + ], + "angle": 0, + "content": "[22] Chuan Guo, Geoff Pleiss, Yu Sun, and Kilian Q. Weinberger. On calibration of modern neural networks. In ICML, 2017. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.207, + 0.893, + 0.247 + ], + "angle": 0, + "content": "[23] Agrim Gupta, Justin Johnson, Li Fei-Fei, Silvio Savarese, and Alexandre Alahi. Social gan: Socially acceptable trajectories with generative adversarial networks. In CVPR, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.249, + 0.894, + 0.276 + ], + "angle": 0, + "content": "[24] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. In NeurIPS, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.278, + 0.894, + 0.317 + ], + "angle": 0, + "content": "[25] Ari Holtzman, Jan Buys, Li Du, Maxwell Forbes, and Yejin Choi. The curious case of neural text degeneration. In ICLR, 2020. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.32, + 0.893, + 0.375 + ], + "angle": 0, + "content": "[26] Anthony Hu, Zak Murez, Nikhil Mohan, Sofia Dudas, Jeffrey Hawke, Vijay Badrinarayanan, Roberto Cipolla, and Alex Kendall. FIERY: Future instance segmentation in bird's-eye view from surround monocular cameras. In ICCV, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.377, + 0.894, + 0.431 + ], + "angle": 0, + "content": "[27] Junjie Huang, Guan Huang, Zheng Zhu, and Dalong Du. BEVDet: High-Performance Multi-Camera 3D Object Detection in Bird-Eye-View. arXiv preprint arXiv:2112.11790, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.434, + 0.894, + 0.473 + ], + "angle": 0, + "content": "[28] Phillip Isola, Jun-Yan Zhu, Tinghui Zhou, and Alexei A. Efros. Image-to-image translation with conditional adversarial networks. In CVPR, 2017. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.476, + 0.894, + 0.503 + ], + "angle": 0, + "content": "[29] Eric Jang, Shixiang Gu, and Ben Poole. Categorical Reparaterization with Gumbel-Softmax. In ICLR, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.505, + 0.893, + 0.531 + ], + "angle": 0, + "content": "[30] Andrej Karpathy. Mingpt. https://github.com/karpathy/minGPT, 2022.8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.533, + 0.893, + 0.573 + ], + "angle": 0, + "content": "[31] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In CVPR, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.576, + 0.893, + 0.615 + ], + "angle": 0, + "content": "[32] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.618, + 0.893, + 0.645 + ], + "angle": 0, + "content": "[33] Diederik P. Kingma and Prafulla Dhariwal. Glow: Generative flow with invertible 1x1 convolutions. In NeurIPS, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.647, + 0.893, + 0.674 + ], + "angle": 0, + "content": "[34] Diederik P Kingma and Max Welling. Auto-encoding variational bayes. In ICLR, 2014. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.676, + 0.893, + 0.716 + ], + "angle": 0, + "content": "[35] Philipp Kähenbuhl and Vladlen Koltun. Efficient inference in fully connected crfs with gaussian edge potentials. In NeurIPS, 2011. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.718, + 0.893, + 0.746 + ], + "angle": 0, + "content": "[36] Ananya Kumar, Percy Liang, and Tengyu Ma. Verified uncertainty calibration. In NeurIPS, 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.747, + 0.893, + 0.788 + ], + "angle": 0, + "content": "[37] Markus Kängsepp and Meelis Kull. Calibrated perception uncertainty across objects and regions in bird's-eye-view. In NeurIPS (Workshop), 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.79, + 0.893, + 0.842 + ], + "angle": 0, + "content": "[38] Alex H. Lang, Sourabh Vora, Holger Caesar, Lubing Zhou, Jiong Yang, and Oscar Beijbom. Pointpillars: Fast encoders for object detection from point clouds. In CVPR, 2019. 2, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.846, + 0.893, + 0.9 + ], + "angle": 0, + "content": "[39] Jesse Levinson, Jake Askeland, Jan Becker, Jennifer Dolson, David Held, Soeren Kammel, J. Zico Kolter, Dirk Langer, Oliver Pink, Vaughan Pratt, Michael Sokolsky, Ganymed Stanek, David Stavens, Alex Teichman, Moritz Werling, and" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8237" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.469, + 0.12 + ], + "angle": 0, + "content": "Sebastian Thrun. Towards fully autonomous driving: Systems and algorithms. In IV, 2011. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.121, + 0.47, + 0.162 + ], + "angle": 0, + "content": "[40] Jesse Levinson and Sebastian Thrun. Robust vehicle localization in urban environments using probabilistic maps. In ICRA, 2010. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.162, + 0.471, + 0.219 + ], + "angle": 0, + "content": "[41] Daiqing Li, Junlin Yang, Karsten Kreis, Antonio Torralba, and Sanja Fidler. Semantic segmentation with generative models: Semi-supervised learning and strong out-of-domain generalization. In CVPR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.219, + 0.471, + 0.259 + ], + "angle": 0, + "content": "[42] Qi Li, Yue Wang, Yilun Wang, and Hang Zhao. Hdmapnet: An online hd map construction and evaluation framework. In ICRA, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.26, + 0.471, + 0.302 + ], + "angle": 0, + "content": "[43] Ming Liang, Bin Yang, Rui Hu, Yun Chen, Renjie Liao, Song Feng, and Raquel Urtasun. Learning lane graph representations for motion forecasting. In ECCV, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.302, + 0.471, + 0.343 + ], + "angle": 0, + "content": "[44] Ming Liang, Bin Yang, Shenlong Wang, and Raquel Urtasun. Deep continuous fusion for multi-sensor 3d object detection. In ECCV, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.344, + 0.471, + 0.399 + ], + "angle": 0, + "content": "[45] Andrew Liu, Richard Tucker, Varun Jampani, Ameesh Makadia, Noah Snavely, and Angjoo Kanazawa. Infinite nature: Perpetual view generation of natural scenes from a single image. In ICCV, 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.4, + 0.471, + 0.44 + ], + "angle": 0, + "content": "[46] Yingfei Liu, Tiancai Wang, Xiangyu Zhang, and Jian Sun. Petr: Position embedding transformation for multi-view 3d object detection. In ECCV, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.441, + 0.471, + 0.483 + ], + "angle": 0, + "content": "[47] Yicheng Liu, Yuan Yuantian, Yue Wang, Yilun Wang, and Hang Zhao. Vectormapnet: End-to-end vectorized hd map learning. arXiv preprint arXiv:2206.08920, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.484, + 0.471, + 0.538 + ], + "angle": 0, + "content": "[48] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin Transformer: Hierarchical Vision Transformer using Shifted Windows. In ICCV, 2021. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.539, + 0.471, + 0.594 + ], + "angle": 0, + "content": "[49] Zhijian Liu, Haotian Tang, Alexander Amini, Xinyu Yang, Huizi Mao, Daniela Rus, and Song Han. Bevfusion: Multi-task multi-sensor fusion with unified bird's-eye view representation. In ICRA, 2023. 1, 2, 3, 4, 6, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.595, + 0.471, + 0.636 + ], + "angle": 0, + "content": "[50] W. Luo, B. Yang, and R. Urtasun. Fast and furious: Real time end-to-end 3d detection, tracking and motion forecasting with a single convolutional net. In CVPR, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.636, + 0.471, + 0.678 + ], + "angle": 0, + "content": "[51] Jiageng Mao, Yujing Xue, Minzhe Niu, Haoyue Bai, Jiashi Feng, Xiaodan Liang, Hang Xu, and Chunjing Xu. Voxel transformer for 3d object detection. In CVPR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.679, + 0.471, + 0.719 + ], + "angle": 0, + "content": "[52] Gellert Mattyus, Shenlong Wang, Sanja Fidler, and Raquel Urtasun. Hd maps: Fine-grained road segmentation by parsing ground and aerial images. In CVPR, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.72, + 0.471, + 0.761 + ], + "angle": 0, + "content": "[53] Andrew Ng and Michael Jordan. On discriminative vs. generative classifiers: A comparison of logistic regression and naive bayes. In NeurIPS, 2001. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.762, + 0.471, + 0.815 + ], + "angle": 0, + "content": "[54] Taesung Park, Jun-Yan Zhu, Oliver Wang, Jingwan Lu, Eli Shechtman, Alexei A. Efros, and Richard Zhang. Swapping autoencoder for deep image manipulation. In NeurIPS, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.471, + 0.859 + ], + "angle": 0, + "content": "[55] Niki Parmar, Ashish Vaswani, Jakob Uszkoreit, Lukasz Kaiser, Noam Shazeer, Alexander Ku, and Dustin Tran. Image transformer. In ICML, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.86, + 0.471, + 0.901 + ], + "angle": 0, + "content": "[56] Jonah Philion and Sanja Fidler. Lift, splat, shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3d. In ECCV, 2020. 1, 2, 3, 4, 6, 8" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.134 + ], + "angle": 0, + "content": "[57] Aditya Prakash, Kashyap Chitta, and Andreas Geiger. Multimodal fusion transformer for end-to-end autonomous driving. In CVPR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.894, + 0.178 + ], + "angle": 0, + "content": "[58] Marc'Aurelio Ranzato, Joshua Sussekind, Volodymyr Mnih, and Geoffrey Hinton. On deep generative models with applications to recognition. In CVPR, 2011. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.179, + 0.894, + 0.221 + ], + "angle": 0, + "content": "[59] Cody Reading, Ali Harakeh, Julia Chae, and Steven L Waslander. Categorical depth distribution network for monocular 3d object detection. In CVPR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.223, + 0.894, + 0.264 + ], + "angle": 0, + "content": "[60] Thomas Roddick, Alex Kendall, and Roberto Cipolla. Orthographic feature transform for monocular 3d object detection. In BMVC, 2019. 2, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.266, + 0.894, + 0.308 + ], + "angle": 0, + "content": "[61] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.31, + 0.894, + 0.352 + ], + "angle": 0, + "content": "[62] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In MICCAI, 2015. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.354, + 0.894, + 0.382 + ], + "angle": 0, + "content": "[63] S. Roth and M.J. Black. Fields of experts: a framework for learning image priors. In CVPR, 2005. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.384, + 0.894, + 0.425 + ], + "angle": 0, + "content": "[64] Tim Salzmann, Boris Ivanovic, Punarjay Chakravarty, and Marco Pavone. Trajectory: Dynamically-feasible trajectory forecasting with heterogeneous data. In ECCV, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.427, + 0.894, + 0.469 + ], + "angle": 0, + "content": "[65] Yuan Shen, Wei-Chiu Ma, and Shenlong Wang. SGAM: Building a virtual 3d world through simultaneous generation and mapping. In NeurIPS, 2022. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.471, + 0.894, + 0.513 + ], + "angle": 0, + "content": "[66] Jianbo Shi and J. Malik. Normalized cuts and image segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 22(8):888-905, 2000. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.515, + 0.894, + 0.571 + ], + "angle": 0, + "content": "[67] Shaoshuai Shi, Li Jiang, Jiajun Deng, Zhe Wang, Chaoxu Guo, Jianping Shi, Xiaogang Wang, and Hongsheng Li. Pvrccnn++: Point-voxel feature set abstraction with local vector representation for 3d object detection. Springer, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.572, + 0.894, + 0.613 + ], + "angle": 0, + "content": "[68] Shaoshuai Shi, Xiaogang Wang, and Hongsheng Li. Pointr-cnn: 3d object proposal generation and detection from point cloud. In CVPR, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.615, + 0.894, + 0.644 + ], + "angle": 0, + "content": "[69] Nitish Srivastava and Russ R Salakhutdinov. Multimodal learning with deep boltzmann machines. In NeurIPS, 2012. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.645, + 0.894, + 0.686 + ], + "angle": 0, + "content": "[70] Deqing Sun, Stefan Roth, and Michael J. Black. Secrets of optical flow estimation and their principles. In CVPR, 2010. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.689, + 0.894, + 0.828 + ], + "angle": 0, + "content": "[71] Sebastian Thrun, Mike Montemerlo, Hendrik Dahlkamp, David Stavens, Andrei Aron, James Diebel, Philip Fong, John Gale, Morgan Halpenny, Gabriel Hoffmann, Kenny Lau, Celia Oakley, Mark Palatucci, Vaughan Pratt, Pascal Stang, Sven Strohband, Cedric Dupont, Lars-Erik Jendrossek, Christian Koelen, Charles Markey, Carlo Rummel, Joe van Niekerk, Eric Jensen, Philippe Alessandrini, Gary Bradski, Bob Davies, Scott Ettinger, Adrian Kaehler, Ara Nefian, and Pamela Mahoney. Stanley: The Robot That Won the DARPA Grand Challenge. 2007. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.829, + 0.894, + 0.871 + ], + "angle": 0, + "content": "[72] Hung-Yu Tseng, Lu Jiang, Ce Liu, Ming-Hsuan Yang, and Weilong Yang. Regularizing generative adversarial networks under limited data. In CVPR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.872, + 0.894, + 0.901 + ], + "angle": 0, + "content": "[73] Arash Vahdat and Jan Kautz. Nvae: A deep hierarchical variational autoencoder. In NeurIPS, 2020. 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8238" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.093, + 0.47, + 0.12 + ], + "angle": 0, + "content": "[74] Aaron van den Oord, Oriol Vinyals, and Koray Kavukcuoglu. Neural discrete representation learning. In NeurIPS, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.472, + 0.162 + ], + "angle": 0, + "content": "[75] Sourabh Vora, Alex H. Lang, Bassam Helou, and Oscar Bei-jbom. Pointpainting: Sequential fusion for 3d object detection. In CVPR, 2020. 2, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.165, + 0.472, + 0.233 + ], + "angle": 0, + "content": "[76] Enze Xie, Zhiding Yu, Daquan Zhou, Jonah Philion, Anima Anandkumar, Sanja Fidler, Ping Luo, and Jose M. Alvarez. \\(\\mathbf{M}^2\\)bev: Multi-camera joint 3d detection and segmentation with unified birds-eye view representation. arXiv preprint arXiv:2204.05088, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.235, + 0.472, + 0.275 + ], + "angle": 0, + "content": "[77] Koichiro Yamaguchi, Tamir Hazan, David McAllester, and Raquel Urtasun. Continuous markov random fields for robust stereo estimation. In ECCV, 2012. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.278, + 0.472, + 0.305 + ], + "angle": 0, + "content": "[78] Yan Yan, Yuxing Mao, and Bo Li. Second: Sparsely embedded convolutional detection. Sensors, 18(10), 2018. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.307, + 0.472, + 0.348 + ], + "angle": 0, + "content": "[79] R. A. Yeh, C. Chen, T. Lim, A. G. Schwing, M. Hasegawa-Johnson, and M. N. Do. Semantic image inpainting with deep generative models. In CVPR, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.35, + 0.472, + 0.39 + ], + "angle": 0, + "content": "[80] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Center-based 3d object detection and tracking. In CVPR, 2021. 1, 2, 3, 4, 6, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.392, + 0.472, + 0.432 + ], + "angle": 0, + "content": "[81] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Multi-modal virtual point 3d detection. In NeurIPS, 2021. 2, 3, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.435, + 0.472, + 0.476 + ], + "angle": 0, + "content": "[82] Wenyuan Zeng, Shenlong Wang, Renjie Liao, Yun Chen, Bin Yang, and Raquel Urtasun. Dsdnet: Deep structured self-driving network. In ECCV, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.478, + 0.472, + 0.518 + ], + "angle": 0, + "content": "[83] Han Zhang, Ian Goodfellow, Dimitris Metaxas, and Augustus Odena. Self-attention generative adversarial networks. In ICML, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.521, + 0.472, + 0.576 + ], + "angle": 0, + "content": "[84] Hang Zhao, Jiyang Gao, Tian Lan, Chen Sun, Benjamin Sapp, Balakrishnan Varadarajan, Yue Shen, Yi Shen, Yuning Chai, Cordelia Schmid, Congcong Li, and Dragomir Anguelov. Tnt: Target-driven trajectory prediction. In CoRL, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.578, + 0.472, + 0.618 + ], + "angle": 0, + "content": "[85] Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, and Jiaya Jia. Pyramid scene parsing network. In CVPR, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.62, + 0.472, + 0.675 + ], + "angle": 0, + "content": "[86] Shuai Zheng, Sadeep Jayasumana, Bernardino Romero-Paredes, Vibhav Vineet, Zhizhong Su, Dalong Du, Chang Huang, and Philip H. S. Torr. Conditional random fields as recurrent neural networks. In ICCV, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.677, + 0.472, + 0.717 + ], + "angle": 0, + "content": "[87] Brady Zhou and Philipp Krahenbuhl. Cross-view transformers for real-time map-view semantic segmentation. In CVPR, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.719, + 0.472, + 0.761 + ], + "angle": 0, + "content": "[88] Jun-Yan Zhu, Taesung Park, Phillip Isola, and Alexei A Efros. Unpaired image-to-image translation using cycle-consistent adversarial networks. In ICCV, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.763, + 0.472, + 0.804 + ], + "angle": 0, + "content": "[89] Song Chun Zhu, Yingnian Wu, and D. Mumford. Frame: filters, random fields, and minimax entropy towards a unified theory for texture modeling. In CVPR, 1996. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.093, + 0.472, + 0.804 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8239" + } + ] +] \ No newline at end of file diff --git a/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/80d4c617-535f-4e51-ba9c-d279342878ed_origin.pdf b/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/80d4c617-535f-4e51-ba9c-d279342878ed_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..e5085c2bc02520eaddb16fef6c6bf93ebd5af3ad --- /dev/null +++ b/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/80d4c617-535f-4e51-ba9c-d279342878ed_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:0b57bc5dbe7e53d7b4067aa1ee27148cee1c1bc1194a8e2254873141b4885606 +size 3829074 diff --git a/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/full.md b/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/full.md new file mode 100644 index 0000000000000000000000000000000000000000..73fef8c152567b355c8a5697291c6ce8b075d659 --- /dev/null +++ b/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/full.md @@ -0,0 +1,464 @@ +# MapPrior: Bird's-Eye View Map Layout Estimation with Generative Models + +Xiyue Zhu1 Vlas Zyrianov1 Zhijian Liu2 Shenlong Wang1 +1University of Illinois at Urbana-Champaign 2MIT + +https://mapprior.github.io + +# Abstract + +Despite tremendous advancements in bird's-eye view (BEV) perception, existing models fall short in generating realistic and coherent semantic map layouts, and they fail to account for uncertainties arising from partial sensor information (such as occlusion or limited coverage). In this work, we introduce MapPrior, a novel BEV perception framework that combines a traditional discriminative BEV perception model with a learned generative model for semantic map layouts. Our MapPrior delivers predictions with better accuracy, realism and uncertainty awareness. We evaluate our model on the large-scale nuScenes benchmark. At the time of submission, MapPrior outperforms the strongest competing method, with significantly improved MMD and ECE scores in camera- and LiDAR-based BEV perception. Furthermore, our method can be used to perpetually generate layouts with unconditional sampling. + +# 1. Introduction + +Accurately understanding the surrounding environment of autonomous vehicles is crucial to guarantee the safety of riders and other traffic participants. Among various perception approaches, Bird's-Eye View (BEV) perception has drawn significant attention in recent years thanks to its capacity to densely model scene layouts and its tight coupling with downstream planning [80, 56, 49]. + +Existing perception models encounter two challenges. The first challenge pertains to the limitations of observations, particularly in distant or occluded regions, resulting in inaccurate predictions. This may manifest in choppy, out-of-distribution, or missing map elements. The second challenge is that most existing models do not consider uncertainty and diversity in possible road layouts. Taking Fig. 1 as an example, the state-of-the-art LiDAR perception model [80] generates incoherent lane markings and sidewalks with massive gaps and cannot quantify the uncertainty and multi-modality as it only produces a single prediction per input. + +This paper presents MapPrior, a novel BEV perception + +![](images/75dd5875b84a2d5682ff0c4150c54471eab0faa1d3c6591af1a4bac819ae2778.jpg) +Figure 1: Existing predictive BEV perception models do not provide realistic scene structures (e.g., the lane and sidewalks have gaps and are not straight). In contrast, our MapPrior is able to accurately recover the layout with a learned prior. These results are validated with a quantitative comparison, showing our method's superior accuracy, realism and uncertainty awareness. + +method that is accurate, realistic, and uncertainty-aware. At the heart of our method is a novel combination of the standard discriminative BEV perception model with a learned deep generative traffic layout prior. Incorporating generative modeling in this predictive task attempts to address the two aforementioned challenges – modeling the data distribution improves realism, and using a sampling process allows generating multiple realistic predictions. Combining our generative model with a discriminative perception model ensures that our method retains a strong predictive ability. + +Our approach comprises two steps, namely the prediction and generative steps. In the prediction step, we use an off-the-shelf BEV perception model [49] to make an initial layout estimate of the traffic scene from sensory input. In the generative step, we use our MapPrior model and initial estimate to sample one or multiple refined layouts. We perform sampling in a learned discrete latent space using a condi- + +tional transformer that is provided with the initial prediction. Finally, the generated tokens are passed into a decoder to output the final layout prediction, which is diverse, realistic, and coherent with the input. The encoder, decoder, and codebook of the MapPrior are trained from real-world map data in an unsupervised way. + +We benchmark our method on the nuScenes dataset against various state-of-the-art BEV perception methods with varying modalities. Our results show that MapPrior outperforms existing methods in terms of accuracy (as reflected by mean intersection-over-union), realism (as reflected by maximum-mean discrepancy), and uncertainty awareness (as reflected by expected calibration error). Furthermore, we demonstrate the unconditional generation capabilities of MapPrior by generating a realistic and consistent HD map of a $30\mathrm{km}$ -long road. + +# 2. Related Work + +Self-driving perception aims to interpret sensory input and establish a representation of the surrounding environment from onboard sensors. It is a critical component for ensuring the safety and efficiency of autonomous vehicles, and various methods have been proposed to improve accuracy and robustness [71, 39]. Traditional approaches for self-driving perception involve multiple (isolated) subtasks, such as localizing against a pre-scanned environment [40, 4], object detection and tracking [38, 80, 68, 44, 50], image segmentation [62, 85, 10] and trajectory prediction [23, 64, 84, 43, 7, 82]. + +Recently, there has been a growing interest in a unified Bird's Eye View (BEV) perception, both in academia [60, 87, 56, 76, 8, 50] and industry [26]. This approach aims to produce a top-down semantic layout of the traffic scene from sensory input, which is efficient, informative, and compact. Notably, the top-down layout is closely linked to downstream 2D motion planning for wheeled robots, making BEV perception particularly suitable for self-driving navigation. + +Various BEV perception modules have been studied in robotics and computer science to improve perception accuracy. These approaches typically take LiDAR [80, 38, 51, 67], multi-view camera [60, 87, 56, 76, 11, 46, 26, 59, 21], or both [81, 75, 49, 2, 57] as input, and output segmentations for road elements and detections for dynamic traffic participants like cars, cyclists or pedestrians. The majority of these methods are supervised and rely on predictive networks like CNNs [59, 67, 80, 38, 44, 60, 56] and transformers [2, 57, 11, 46, 51, 87, 21, 26, 27]. Despite their success, there are still unresolved challenges. For example, real-world traffic layouts are highly structured, with straight lane marks, strong topological relationships, and sharp road element boundaries. But such structures have proven difficult to preserve in the BEV perception output map, even + +with state-of-the-art methods, as shown in Fig. 1. This can harm the realism of perception output and the practicality of the resulting map for motion planning. Additionally, most networks make a single layout estimation without diversity or calibrated uncertainty, leaving the autonomy vulnerable to catastrophic failure. + +HDMapNet [42], VectorMapNet [47], and others [52, 8] have been proposed to address the issue of layout structure by introducing a vectorized output map format with implicitly structured priors. However, this approach fails to account for all layer types and still produces significant artifacts in regions with limited observations. Very recently, calibrated confidence scores have been investigated to address the aforementioned uncertainty issue [37, 13], but the inherent multi-modal uncertainty in BEV perception remains under-explored. + +In contrast, our approach leverages generative modeling as a map prior, which encodes the rich structure of the traffic scene. Our conditional generative modeling also allows us to sample multiple diverse outputs for the same input. Consequently, our results are more accurate and realistic with better multi-modal uncertainty modeling. + +Generative models. Our approach to generative BEV perception involves learning a map prior and performing conditional sampling using deep generative models. Generative models learn to capture the underlying structure of the data distribution and create new, diverse samples. Several well-known approaches include VAEs (variational autoencoders) [34, 73], which use variational inference to learn a latent space model, and autoregressive models [55], which decompose the generation problem into simpler conditional generation tasks. GANs (generative adversarial networks) [20, 83, 1, 31, 28, 72, 5] use an adversarial loss to train networks to convert noise into samples. Flow-based models [33, 15] exploit an invertible process to sample from a proposal distribution. Recently, diffusion models [14, 24] have been developed that generate samples through a denoising-diffusion process. Our method leverages vector-quantized generative models [74, 18, 9], which use a discrete-valued latent space representation that is powerful, structure-preserving, and efficient for conditional sampling. Specifically, we build our map prior on top of this approach to capture the discrete structure of the map data and generate high-quality samples. + +Generative approach for vision. Our approach belongs to the broader category of generative modeling approaches in computer vision [79, 53, 58, 69], which includes Markov random fields (MRFs), factor graphs, energy-based models, deep generative models, among others. These practices date back to the 1970s. In contrast to discriminative or predictive approaches, generative approaches often tackle the task + +![](images/ea864e38c632ef366352e51153a39bf086dcb0821989689642279a77c040e984.jpg) +Figure 2: MapPrior first makes use of an off-the-shelf perception model to generate an initial noisy estimate from the sensory input. It then encodes the noisy estimate into a discrete latent code using a generative encoder and generates various samples through a transformer-based controlled synthesis. Finally, MapPrior decodes these samples into outputs with a decoder. + +as a marginal sampling or MAP inference problem, which is more effective at utilizing strong prior knowledge and modeling uncertainty. Representative works can be seen in low-level vision [19, 89], optical flow [70, 63], and image segmentation [66, 35, 86]. Generative approaches with conditional sampling have often been investigated in vision tasks involving multimodality or uncertainty, such as image editing [88, 28, 12, 54], image segmentation [41] and stereo estimation [16, 77]. However, few studies have explored their use in self-driving perception, despite its inherent multimodal uncertainty nature. + +# 3. Approach + +The objective of this research is to develop a method that can generate a precise, realistic, and uncertainty-aware map layout from sensory input in one or a few modalities. To achieve this, we introduce a new framework named MapPrior that combines the predictive capability of discriminative models with the capacity of generative models to capture structures and uncertainties. We present a two-stage conditional sampling framework to explain our approach and detail the implementation of each module. Additionally, we discuss our design decisions, the learning process, and how our approach relates to previous methods. + +# 3.1. Overview + +**Formulation.** We formulate the probabilistic BEV perception problem as a conditional sampling task. Given the sensory input $\mathbf{x} \in \mathcal{X}$ (which could be from a camera, LiDAR or multiple sensors), we aim to find one or multiple plausible traffic layouts $\mathbf{y} \in \mathcal{Y}$ from the top-down bird's-eye view. The traffic layout $\mathbf{y}$ is a multi-layer binary map centered at the ego vehicle. Conventional methods [49, 80, 56, 81, 76] rely on a deterministic predictive network $\mathbf{y} = f_{\theta}(\mathbf{x})$ to provide a single output estimation. We propose, instead, to use a generative vector-quantized latent space model to model + +the uncertainty and diversity. Specifically, we aim to design a conditional probability model $p_{\theta}(\mathbf{y}|\mathbf{x})$ that can sample our desired output $\mathbf{y}$ from a distribution. This allows us to explicitly model uncertainty and generate multiple plausible traffic layouts. + +Motivation. Intuitively speaking, the objective of a predictive perception model is to produce a coherent semantic layout that best represents the sensory input. However, this training objective does not necessarily optimize for structure preservation or realism. For example, minor defects in lane markers might not significantly affect cross-entropy, but could drastically impact downstream modules due to topological changes. On the other hand, a generative prior model, such as a GAN, is trained to capture realism in structures. The advantage of such a model is that it can be trained on HD map collections, without paired data, in an unsupervised manner. This insight inspires our proposed solution, which combines a predictive model with a generative model to tackle the conditional sampling task with both coherence and realism in mind. + +# 3.2. Inference + +In our framework, the distribution $p_{\theta}(\mathbf{y}|\mathbf{x})$ is defined implicitly using a latent model $\mathbf{z}$ . The framework comprises of a predictive stage and a generative stage. During the predictive stage, the perception module $F(\mathbf{x})$ generates an initial noisy estimate $\mathbf{y}'$ for input $\mathbf{x}$ . For the generative stage, we take inspiration from recent successful techniques in vector-quantized generation [18, 9, 61] for conditional sampling and use a VQGAN-like model to generate multiple realistic samples. To achieve this, we encode the noisy estimate $\mathbf{y}'$ into a discrete latent code $\mathbf{z}'$ using a generative encoder $E(\mathbf{y}')$ . This latent code $\mathbf{z}'$ and the sensory input $\mathbf{x}$ then guide the generative synthesis process through a transformer-based controlled synthesis in the latent space, producing various + +samples $\{\mathbf{z}^{(k)}\sim p(\mathbf{z}|\mathbf{z}',\mathbf{x})\}$ . Finally, these samples are decoded into multiple output samples using a decoder $G(\cdot)$ : $\mathbf{y}^{(k)} = G(\mathbf{z}^{(k)})$ , which provides our final layout estimation samples. Fig. 2 depicts the overall inference framework. + +Predictive stage. The predictive stage aims to establish reliable initial layout estimation that can act as a guiding control during the conditional sampling stage. To achieve this, we have incorporated a predictive sensory backbone, VoxelNet [78, 80] for LiDAR and Swin Transformer [48] for multi-view camera inputs. The sensory backbone networks first extract features from the sensory space and then project them into bird's eye view features. For the LiDAR input, a 3D convolution backbone is utilized as a feature extractor, and the LiDAR features are flattened along the height dimension to project them to BEV. In contrast, for the camera input, a hierarchical transformer is used as a feature extractor for each view, and monocular depth estimation and view transformation are applied to project the features to BEV. The predictive model employs a convolutional segmentation head to generate the layout estimates, denoted by $\mathbf{y}' = F(\mathbf{x})$ . It should be noted that the resulting BEV map achieves a reasonable intersection-over-union score (IoU). However, as Fig. 1 highlights, the model suffers from unrealistic structures, missing road elements, and noise, particularly in regions with limited observations. + +Generative stage. To enhance the quality and diversity of our perception, we incorporate a generative map prior in the second stage for conditional generation. The generative map prior is built on a VQGAN architecture [18], which consists of three learnable components: the encoder $E$ , the decoder $G$ , and the codebook $\mathcal{C} = \{\mathbf{c}_j\}$ with $j$ being the code index. The encoder transforms a traffic layout into a latent feature map, where each element of the spatial map is chosen from one of the codes in the codebook as follows: + +$$ +\mathbf {z} _ {t} (\mathbf {y}) = \underset {\mathbf {c} _ {j} \in \mathcal {Z}} {\arg \max } \| \mathbf {c} _ {j} - E _ {t} (\mathbf {y}) \| _ {2} ^ {2}, \quad \forall t \tag {1} +$$ + +where $t$ is the $t$ -th entry of the feature map $\mathbf{z}$ . The decoder then transforms the latent code back to the layout map space: $G(\mathbf{z}(\mathbf{y}))$ . Sampling from this prior can be done by randomly drawing a latent code and decoding it into a layout map. The discrete-valued auto-encoder architecture greatly regularizes the output space in a structured manner, preventing it from producing unrealistic reconstructions, as shown in Fig 1. + +During conditional sampling at inference, we first encode the noisy estimate $\mathbf{y}'$ into a discrete latent code $\mathbf{z}'$ using a generative encoder $E$ . This latent code $\mathbf{z}'$ and the sensory input $\mathbf{x}$ are then used as guidance by a transformer $T(\mathbf{z}',\mathbf{x})$ for the generative synthesis of the latent space, producing various samples $\mathbf{z}^{(k)}\sim p(\mathbf{z}|\mathbf{z}',\mathbf{x}) = T(\mathbf{z}',\mathbf{x})$ . Specifically, we use an autoregressive scheme to progressively sample + +each code, i.e. $p(\mathbf{z}|\mathbf{z}',\mathbf{x}) = \prod_{t}p(\mathbf{z}_{t}|\mathbf{z}_{< t}^{(k)},\mathbf{z}',\mathbf{x})$ . At the $t$ -th step, the transformer takes as input the current latent code $\mathbf{z}_{< t}$ , the guidance code $\mathbf{z}'$ as well as encoded sensory feature $\mathbf{x}$ as input tokens, and outputs the next token's probability over the codebook $p(\mathbf{z}_t|\mathbf{z}_{< t}^{(k)},\mathbf{z}',\mathbf{x})$ : + +$$ +\mathbf {z} _ {t} ^ {(k)} \sim p \left(\mathbf {z} _ {t} \mid \mathbf {z} _ {< t} ^ {(k)}, \mathbf {z} ^ {\prime}, \mathbf {x}\right) \tag {2} +$$ + +where $p(\mathbf{z}_t|\mathbf{z}_{< t}^{(k)},\mathbf{z}',\mathbf{x})$ is the conditional probability estimated from the transformer. We use nucleus sampling [25] to get multiple diverse $\mathbf{z}^{(k)}$ , which trades-off between sampling quality and diversity. Finally, these samples are decoded into multiple output samples using a decoder $G(\cdot)$ : $\mathbf{y}^{(k)} = G(\mathbf{z}^{(k)})$ , which provides our final layout estimation samples. Formally speaking, the entire second stage can be written as follows: + +$$ +\mathbf {y} ^ {(k)} = G \left(\mathbf {z} ^ {(k)}\right) \text {w h e r e} \mathbf {z} ^ {(k)} \sim p \left(\mathbf {z} \mid \mathbf {z} ^ {\prime}, \mathbf {x}\right). \tag {3} +$$ + +One-step generation. To enhance inference speed, we introduce a one-step variant of MapPrior, which generates a single sample rather than multiple diverse ones. It also produces tokens in a single step, bypassing the autoregressive sampling strategy: + +$$ +\mathbf {y} = G (\mathbf {z}) \text {w h e r e} \mathbf {z} \sim p (\mathbf {z} | \mathbf {x}). \tag {4} +$$ + +This provides an effective way to trade off between the generation quality and efficiency. + +# 3.3. Learning + +The training process consists of three individual components. Firstly, the perception module, denoted as $F$ , is learned to produce a reliable initial layout estimation. Secondly, the encoder, decoder, and codebook (denoted as $E$ , $G$ , and $C$ , respectively) are jointly trained to represent a strong map prior model. Lastly, given a fixed map prior model, the conditional sampling transformer $T$ is learned to sample high-quality final results. In the following, we will provide a detailed description of each component's training procedure. + +Training the perception module. To train the perception module $F$ , we follow the standard practice adopted in prior works [49, 56] and employ a binary cross-entropy loss. The objective function is defined as follows: $\min_F - [\mathbf{y}_{\mathrm{gt}}\log \mathbf{y}']$ where $\mathbf{y}_{\mathrm{gt}}$ denotes the ground-truth label, and $\mathbf{y}' = F(\mathbf{x})$ is the corresponding prediction given the input $\mathbf{x}$ . + +Training the map prior model. The training procedure for the map prior model involves jointly optimizing the encoder $E$ , decoder $G$ , and the fixed-size codebook $C$ in an end-to-end fashion. We use a vector-quantized auto-encoder + +![](images/953c05ee9133618fc0e66d6f33e24a50dc149a602caf085862d1ca357f929e74.jpg) +Figure 3: MapPrior can be exploited in a progressive manner to generate perpetual traffic layouts. At each step, we choose a local area to sample to fill unexplored regions and expand the frontiers. + +![](images/cca346dd01809a0c68ebecc0918edce15d9b156e94b831f6d2894d5cec8b12c8.jpg) + +![](images/c074f79466bfcba57c21d94e5c6673eafd21f7d16ae0e1251f0236e2ed10e88a.jpg) + +![](images/0e5be95741a3e5cd1d220944ef867e075e81ea614b7a2ab1bbd4d1d8897d2b8c.jpg) + +to reconstruct the input data $\mathbf{y}$ through $\hat{\mathbf{y}} = G(\mathbf{z}(\mathbf{y}_i))$ following Eq. 1. The following losses are minimized: + +$$ +\min _ {E, G, \mathcal {C}} \max _ {D} \mathcal {L} _ {\text {r e c o n}} + \lambda_ {\text {G A N}} \mathcal {L} _ {\text {G A N}} + \mathcal {L} _ {\text {l a t e n t}}. \tag {5} +$$ + +The first term, $\mathcal{L}_{\mathrm{recon}}$ , is the reconstruction loss, which is designed to maximize the agreement between the input $\mathbf{y}$ and the reconstructed output: + +$$ +\mathcal {L} _ {\text {r e c o n}} = \left\| \hat {\mathbf {y}} - \mathbf {y} \right\| ^ {2}. \tag {6} +$$ + +In addition to the reconstruction loss, the second term is a GAN loss inspired by VQGAN [18] to encourage the reconstructed output to be realistic with a clear local structure and topology. A local discriminator $D(\cdot)$ is trained to differentiate between real and reconstructed BEV layout using cross-entropy loss, and the $\mathcal{L}_{\mathrm{GAN}}$ loss aims to make the reconstructed image as realistic as possible through fooling the discriminator: + +$$ +\mathcal {L} _ {\mathrm {G A N}} = \log D (\mathbf {y}) + \log (1 - D (\hat {\mathbf {y}})), \tag {7} +$$ + +where $\mathbf{y}$ is a real sample and $\hat{\mathbf{y}}$ is a reconstructed sample. Following VQGAN [18], this loss is rescaled by + +$$ +\lambda_ {\mathrm {G A N}} = g _ {\mathrm {r e c}} / \left(g _ {\mathrm {G A N}} + \sigma\right), \tag {8} +$$ + +where $g_{\mathrm{rec}}$ and $g_{\mathrm{GAN}}$ are gradients of $\mathcal{L}_{\mathrm{rec}}$ and $\mathcal{L}_{\mathrm{GAN}}$ with respect to the last layer of the generator. + +The last term promotes the expressiveness of the codebook. We expect the latent feature $E(\mathbf{y})$ to be close to its nearest codebook token and vice versa. Thus, the latent loss is defined as + +$$ +\mathcal {L} _ {\text {l a t e n t}} = \left\| \mathbf {z} - \operatorname {s g} [ E (\mathbf {y}) ] \right\| ^ {2} + \left\| \operatorname {s g} [ \mathbf {z} ] - E (\mathbf {y}) \right\| ^ {2}, \tag {9} +$$ + +where $\mathrm{sg}[\cdot ]$ is a gradient detach operator. + +Training the conditional sampler. Our conditional sampling transformer, denoted as $T$ , is trained in the latent code space to sample high-likelihood latent codes given input controlling guidance. Given a paired input and output $(\mathbf{x},\mathbf{y})$ and fixed perception module $F$ , map prior model $E,G,C$ , the transformer is trained using the following objective: + +$$ +\min _ {T} \mathcal {L} _ {\mathrm {C E}} + \mathcal {L} _ {\text {o u t}}. \tag {10} +$$ + +The first loss, $\mathcal{L}_{\mathrm{CE}}$ , optimizes the transformer to maximize the estimated probability of the latent code of the ground-truth layout. We use a cross-entropy loss between the transformer's estimated probability $T(\mathbf{z}',\mathbf{x})$ and the ground-truth sample $\mathbf{y}$ : + +$$ +\mathcal {L} _ {\mathrm {C E}} = \sum_ {t} \sum_ {i} \mathbf {y} _ {i, t} \log T _ {i, t} \left(\mathbf {z} ^ {\prime}, \mathbf {x}\right), \tag {11} +$$ + +where, $i$ represents the $i$ -th output label, and $t$ represents the $t$ -th autoregressive step. + +Although making the latent code closer to the ground-truth map's latent code is essential, it is not sufficient to ensure high output fidelity. Hence, we include an additional reconstruction output loss that encourages the transformer to favor samples that produce high-accuracy layouts. Similar to the reconstruction loss in auto-encoding training, an L2 reconstruction loss is used: + +$$ +\mathcal {L} _ {\text {o u t}} = \left\| \mathbf {y} - \hat {\mathbf {y}} \right\| _ {2} ^ {2}, \tag {12} +$$ + +where $\mathbf{y}$ is the true map and $\hat{\mathbf{y}}$ is the predicted map. Note that codebook selection in latent code space is non-differentiable; thus, we use Gumbel-Softmax [29] to ensure differentiability in practice throughout the training processes. + +# 3.4. Discussions + +Uncertainty quantification. Our latent transformer offers diverse results $\mathbf{y}^{(k)}$ by using a conditional sampling scheme. By estimating the variance of $\mathbf{y}^{(k)}$ , we can estimate the uncertainty map for our results. By using the average of $\mathbf{y}^{(k)}$ , we aggregate the diverse result samples to a more stable and better calibrated results. + +Perpetual layout generation. Our trained map prior enables the continuous generation of realistic and varied driving sequences, which are extremely valuable for content creation and autonomous driving simulations. We use a progressive generation strategy, which builds upon prior works [3, 17, 45, 65, 18, 9]. The strategy involves iteratively expanding our visual horizon and generating new content by leveraging our map prior model to fill in the previously unseen areas. We illustrate this process in Fig. 3. + +Table 1: Quantitative results of BEV map segmentation on nuScenes. Our MapPrior achieves better accuracy (IoU), realism (MMD) and uncertainty awareness (ECE) than discriminative BEV perception baselines. + +
ModalityIoU (↑)MMD (↓)ECE (↓)
DrivablePed. XWalkwayStop LineCarparkDividerMean
OFT [60]C74.035.345.927.535.933.942.154.50.045
LSS [56]C75.438.846.330.339.136.544.443.20.041
BEVFusion-C [49]C81.754.858.447.450.746.456.639.60.038
MapPrior-CC81.754.658.346.753.345.156.728.40.026
MapPrior-C (1 step)C81.654.658.446.853.945.156.728.7-
PointPillars [38]L72.043.153.129.727.737.543.8153.00.111
BEVFusion-L [80, 49]L75.648.457.536.531.741.948.6115.20.090
MapPrior-LL81.049.758.037.538.242.451.135.80.038
MapPrior-L (1 step)L80.149.057.837.833.042.550.050.2-
PointPainting [75]C+L75.948.557.136.924.541.949.1109.80.099
MVP [81]C+L76.148.757.036.933.042.249.0115.30.096
BEVFusion [49]C+L85.560.567.652.057.053.762.721.60.038
MapPrior-CLC+L85.361.467.151.760.053.363.128.00.020
MapPrior-CL (1 step)C+L85.361.367.051.759.653.163.028.1-
+ +# 4. Experiments + +We evaluate our MapPrior on BEV map segmentation and generation tasks for both LiDAR and camera modalities. We evaluate our approach to generate an accurate and realistic traffic layout both quantitatively and qualitatively in Sec. 4.2. We show how output loss and BEV features can affect our performance in Tab. 2. We finally estimate how our model can generate diverse samples and how our model is calibrated using the diverse samples in Fig. 5 and 6. Specifically, we are interested in seeing how using a generative prior affects accuracy (reflected by mIoU), realism (reflected by MMD), and model calibration (reflected by ECE). + +# 4.1. Experimental Setup + +Datasets. We evaluate our model on nuScenes [6], a large-scale outdoor autonomous driving dataset containing 1000 driving scenes, consisting of 700 scenes for training, 150 for validation, and 150 scenes for testing. It has around 40,000 annotated key-frames, each with six monocular camera images encompassing a 360-degree FoV (used by camera models), and a 32-beam LiDAR scan (used by LiDAR models). We follow the train/validation split provided by nuScenes. We evaluate all models on the validation set following common practices in BEV layout estimation [49, 56]. The ground truth segmentation map is provided by nuScenes and was labeled manually [6]. We rasterized the map layers from the nuScenes map into the ego frame. + +Metrics. We provide quantitative results for both segmentation and generative tasks. For BEV map segmentation, + +our metric is the Intersection-over-Union (IoU score) for six map classes (drivable area, pedestrian crossing, walkway, stop line, car-parking area, and lane divider), as well as the mean IoU averaged over all six map classes. Since different classes may overlap, we separately compare the IoU score for each class. For all baseline predictive models, we choose the best threshold that maximizes IoU for comparison to ensure no bias is introduced due to the suboptimal threshold selection. For MapPrior, we simply use 0.5 as the threshold. + +To evaluate generated map layout realism, we use the maximum mean discrepancy (MMD) metric. MMD effectively measures the distance between two distributions of two sets of samples by measuring the squared difference of their mean in different spaces: + +$$ +\begin{array}{l} \mathrm {M M D} = \sum_ {i} ^ {n} \sum_ {i ^ {\prime}} ^ {n} k (\mathbf {x} _ {i}, \mathbf {x} _ {i ^ {\prime}}) / n ^ {2} + \sum_ {j} ^ {m} \sum_ {j ^ {\prime}} ^ {m} k (\mathbf {x} _ {j}, \mathbf {x} _ {j ^ {\prime}}) / m ^ {2} \\ - 2 \cdot \sum_ {i} ^ {n} \sum_ {j} ^ {m} k \left(\mathbf {x} _ {i}, \mathbf {x} _ {j}\right) / n m. \tag {13} \\ \end{array} +$$ + +To evaluate a set of predicted layouts, we compare it with a set of ground truth layouts from nuScenes. + +To evaluate uncertainty in our diversity results, we use Expected Calibration Error (ECE) [36, 22]. ECE compares output probabilities to model accuracy. It splits the results into several bins and measures a weighted average discrepancy between accuracy and confidence within each bin: + +$$ +\mathrm {E C E} = \sum_ {b} ^ {B} n _ {b} | \operatorname {a c c} (b) - \operatorname {c o n f} (b) | / n, \tag {14} +$$ + +![](images/8c0a7cd2ec75e19801d69437c071be755b8dba191b69914ad980e8322936f809.jpg) +LiDAR + +![](images/c6056e214c5e7ad83f84a11833a522ce91be20bd4309524ee214f31e0d2237b6.jpg) +PointPillars + +![](images/91e9b2d302669c58fc7b2a539837ba5fd40a41af99df56172a922038615ffe52.jpg) +BEVFusion-L + +![](images/59a64753780a79c0d7b7d9e81693a0c999777c379f5f8125a530f956e3aba46a.jpg) +MapPrior-L (Ours) + +![](images/821ca6780cdf4b03e11c80221f178af8630bc5c138ca0fc20418c995106d8855.jpg) +Ground Truth + +![](images/3b004600bd4c1323365e21a3afa15a06d6a61252d7a09e58d8e80ac180ac310e.jpg) +Camera + +![](images/d4f3cb944cbccd6bec267d3c2352aaf29f95d9c19f45aecaaf682c914b0025a7.jpg) +LSS + +![](images/7d5c983dc468668b9c00dfeca3308d9d1abf3d45bda8c6afad51e49a9caf4198.jpg) +BEVFusion-C + +![](images/03c37265a3456af4e3481128b0c1bf03f54f4e6935a7c62f5178e76355360829.jpg) +MapPrior-C (Ours) + +![](images/c1619230200892b0940f88f483493b5dd77e80f150431ee1ed19cd075f44d580.jpg) +Ground Truth + +![](images/c105640b6fbfec181b3a8bad34335c909a84df41f252be75113bf336096f4633.jpg) +LiDAR + +![](images/d86c05ac6253002579e4dfbf6d49c953b0d943a0cc897e4464eac1002b6ba57c.jpg) +Camera + +![](images/7a7434b0aadebd182e7ec8587e88bd28cef3fb2a8640ce61279bbc34f43d8115.jpg) +BEVFusion-CL + +![](images/5a2968f5a77acc40447164e0f8b6da72c064db29f42f328f1c152df7797271c4.jpg) +MapPrior-CL (Ours) + +![](images/ad1364e78541555d8ca3946ecdb59ce51a9525c567e783f93e0d822aabbb166c.jpg) +Ground Truth + +![](images/6a89fa43641c322d2b06e5ec347db4dea8b7add94db677290eae51de8bd95f96.jpg) +Figure 4: Qualitative results of BEV map segmentation on nuScenes. Discriminative BEV perception baselines produce results with clear artifacts (e.g., lane markings are discontinuous, roads and pedestrian walkways have unrealistic gaps, etc.). In contrast, our MapPrior produces semantic map layouts that are clean, realistic, and in-distribution. + +![](images/04f60e24881c3e2c2fcf8aeaace46a1ad8b9dd74188d036439cbf2dbce2cf6f3.jpg) +Input + +![](images/e5e48dccf8aca33770969d1ea6f6fae01a0231033930f7a2ed982897cd680ef1.jpg) + +![](images/0544d9923024765b5bbe5c09d25563d7a95a7e70e8b2742f7abd7e304205e927.jpg) +GT + +![](images/e72a1a1e7221652d0c2f5a07befa49eed0c07fb61420f9911088fb271af0de4c.jpg) + +![](images/c8c4c631599a0ea43c374d792df7fe1bacff4faa433e871ca382a49974a218a4.jpg) +Our Sample 1 + +![](images/c2328f4c083ac74f2c2a991d1014b839d6f93caca949c146b6ec7a90159fdbed.jpg) + +![](images/225cf090e1996ed4cdd3121d861aa83f2b8417261eb64ecfd93cc7a20e7acf02.jpg) +Our Sample 2 + +![](images/0a3e9d834cf49ab30040649b7970ed1690dc6669521882bbaaf0674a53ddb1a3.jpg) + +![](images/e0a1ae028c9ca7ecd9a704888f1276391f3ea02ddd47db34de9fa42d326b775e.jpg) +Our Sample 3 +Figure 5: Qualitative results of diversity on NuScenes. + +![](images/a7159444af1fcc0bdfc49e41d8b459001c907787a889b5e736fe00efd4e23d2e.jpg) + +![](images/6197df6b885b76d0627b30d1661d1dc12fbc18fa526987ef51cb8ad08044ae2a.jpg) +Uncertainty Map + +where acc is the empirical accuracy, and conf is the estimated confidence for each bin, $n_b$ is the # of samples per each bin and $n$ is the total # of samples. ECE is an important metric in BEV map segmentation, as ignoring uncertainties can lead to bad consequences in driving planning. We gener + +ate 15 diverse outputs for every instance and use the mean as the confidence. The baseline model is trained end-to-end with cross-entropy loss, so the predictions produced by the softmax function are assumed to be the pseudo probabilities. + +![](images/4923dbae83ba9d325b35ff0f5a967f0c89c3a518cf70478d1aab7ed98c7044a7.jpg) +LiDAR + +![](images/36bd2ed41022c4b45941e5e0b362513f447d1de006d59ce9a94862f6d85355fd.jpg) +Prediction + +![](images/007f185348c48b58927f8ca278f458835c16eb4625a6379e33692aa2ab4bff99.jpg) +Uncertainty +BEVFusion-C + +![](images/dc5aaf86de4d38714bface5b89d7901bd31514f2effdb6580628cb1438e871ce.jpg) +Error Map +Figure 6: Prediction, uncertainty, and error map comparison between BEVFusion-C and MapPrior. BEVFusion generates a misguided uncertainty boundary by giving high weight to areas where map elements are unlikely to be. In comparison, MapPrior's uncertainty is constrained to map element boundaries. This is further confirmed with the error map, where MapPrior's uncertainty map closely matches the error map. + +![](images/e5cdc9ad14a4d8f2babf0ae2a67e60ef3e14e81ef65dff7a611f96ef0d7ffb85.jpg) +Prediction + +![](images/2e0d8852bf49a33ce7b9dd9e0cda87589ed9864567521be4667122d23cf8c05c.jpg) +Uncertainty +MapPrior + +![](images/866965474c9d5def163e49624c80ddd3e183bb1da3ca001d82c9b8387564d88a.jpg) +Error Map + +Table 2: Ablation studies for MapPrior on nuScenes. + +
Output Loss LoutT(z') or T(z', x)mIoU (↑)MMD (↓)
-T(z')45.633.3
✓T(z')49.045.6
✓T(z', x)51.135.8
+ +Baselines. For LiDAR-only segmentation, we use Point-Pillars [38], and BEVFusion-L [49, 80] as our baselines. To the best of our knowledge, BEVFusion-L is the current state-of-the-art method in LiDAR-based BEV map segmentation. + +For camera-only segmentation, our baseline model are LSS [56], OFT [60], and BEVFusion-C [49]. Among them, BEVFusion-C is the current state-of-the-art model with a significantly higher IoU score than other methods. We use open-source code from BEVFusion. We also provide results of multi-modal models [49, 75, 81] for reference. + +Implementation details. Following [49], we perform segmentation in a $[-50\mathrm{m}, 50\mathrm{m}] \times [-50\mathrm{m}, 50\mathrm{m}]$ region around the ego car with a resolution of 0.5 meters/pixel, resulting in a final image size of $200 \times 200$ . Since map classes may overlap, our model performs binary segmentation for all classes. The encoder and decoder comprise four downsampling and four upsampling blocks processing a series of 128-256-512-256-128 channels. Each block comprises 2 reset blocks and one convolution and uses sigmoid activation and GroupNorm. The resolution of the latent space is [12,12]. + +For the generative step, we train a minGPT [30] transformer conditioned on the generated sequence, extracted BEV features, and the initial noisy map. We train the whole model using Adam [32] with a learning rate of 9.0e-6. The + +transformer's BEV feature encoder for the transformer has a similar structure to the model encoder consisting of 3 down-sampling blocks. The BEV feature encoder converts the original BEV features shaped [128, 128] into latent space tokens shaped [12, 12]. We apply a multiplier of 100 on the output loss to balance the magnitude of different losses. + +# 4.2. Map Segmentation as Generation + +Quantitative results. We show our quantitative results for map segmentation in Tab. 1. The results show that MapPrior achieves state-of-the-art performance. Comparing with BEVFusion-L, our MapPrior-L offers $2.5\%$ improvement in mIoU, which is brought purely by our proposed generative stage. Furthermore, MapPrior provides a substantial improvement in the MMD score compared to baselines. MMD is a metric of distance between the generated layout predictions and the ground truth distribution. This shows that MapPrior's outputs closely match the ground truth data distribution. In addition, this stark difference in MapPrior's MMD performance compared to the baselines implies that the realism metric and precision metric are not closely coupled. It is possible to achieve higher IoU while generating non-realistic samples, or vice versa. Our approach simultaneously pushes the limit of the two. + +Moreover, inference speed is vital for MapPrior. Using an RTX A6000 GPU, we compared the inference speeds of our model and BEVFusion in terms of frames per second (FPS). Our findings are presented in Tab. 3. These results indicate that one-step MapPrior is significantly closer to real-time performance compared to the standard MapPrior, with only a minor trade-off in IoU for increased uncertainty awareness. + +Qualitative results. We show our qualitative results in Fig. 4. Compared to other methods, MapPrior can consist + +![](images/2b991d78bdfd586d60cb83d7c6a8fe1597c651151e1d79e7bb8489f387f11cdc.jpg) +Figure 7: Results for perpetual traffic scene generation. Two road subsections are shown here. + +Table 3: Performance of one-step MapPrior. + +
ModalitymIoU (↑)MMD (↓)FPS
BEVFusion-C [49]C56.639.68.85
MapPrior-CC56.728.40.60
MapPrior-C (1 step)C56.728.74.26
BEVFusion-L [80, 49]L48.6115.27.52
MapPrior-LL51.135.80.57
MapPrior-L (1 step)L50.050.24.88
BEVFusion [49]C+L62.721.65.52
MapPrior-CLC+L63.128.00.55
MapPrior-CL (1 step)C+L63.028.13.61
+ +tently generate coherent and realistic class predictions within the entire map region. Our model has a more coherent divider layout, whereas the baseline methods usually have broken/missing lane dividers. In the baseline methods, the stopline is often jagged and appears disconnected from the road. In distant areas from the ego car, our model tries to make a plausible layout estimate when other methods fail due to limited observations (this is especially noticeable in the pedestrian walkways). The edges from our method are also more smooth, resulting in a more realistic estimation. + +Diversity and uncertainty calibration. We show that our model can produce a better-calibrated layout with diversity. In Fig. 5, we show that our model can generate multiple diverse and feasible layouts, All of which are realistic. + +By aggregating the diverse samples, our model can produce a calibrated uncertainty map. We show our results in Fig. 6. Compared to the baselines (which are unable to generate multiple samples), our uncertainty map aligns with the error map much more accurately. ECE scores in Tab. 1 further validate this quantitatively. + +Perpetual generation. We show our qualitative results for generating 'infinite' roads in Fig. 7. We have generated a single $30\mathrm{km}$ long road. Due to size constraints, we are only able to show a subsection. The generated traffic scene contains a highway with intermittent intersections resembling a + +road layout in a city. We provide the entire road as a gif in our supplementary materials. + +# 4.3. Discussions + +Ablation studies. To justify our design, we provide ablation studies in Tab. 2. L2 loss at the output end changes the model's optimization target. It puts more weight on generating accurate results as opposed to generating i.i.d. data. Therefore, the model achieves a higher IoU score at the cost of a slightly worse MMD. Providing the transformer with BEV features boosts the performance by around $3\%$ in the IoU score, and decreases MMD by around $21\%$ . + +Inference speed. Inference speed is essential for MapPrior, especially given the real-time demands of autonomous driving. While transformers offer remarkable generative abilities, they inherently slow down performance due to their sequential token generation process. Moreover, the need for MapPrior to produce diverse outcomes further curtails its inference speed. To address this, we introduced the one-step variant of MapPrior, which predicts a single sample for each input and generates all tokens simultaneously. As evidenced in Tab. 3, the one-step MapPrior registers a marginally worse MMD score and falls short in uncertainty awareness. Nonetheless, the one-step MapPrior markedly outpaces the standard MapPrior in speed. + +# 5. Conclusion + +This paper presents MapPrior, a novel generative method for performing BEV perception. The core idea is to leverage a learned generative prior over traffic layouts to provide diverse and accurate layout estimations, which potentially enable more informed decision-making and motion planning. Our experiments show that our approach produces more realistic scene layouts, enhances accuracy, and better calibrates uncertainty compared to current methods. + +Acknowledgement. The project is partially funded by the Illinois Smart Transportation Initiative STII-21-07, an Amazon Research Award, an Intel Research Gift, and an IBM IIDAI grant. We also thank NVIDIA for the Academic Hardware Grant. VZ is supported by the Frontier Fellowship. + +# References + +[1] Martin Arjovsky, Soumith Chintala, and Léon Bottou. Wasserstein generative adversarial networks. In ICML, 2017. 2 +[2] Xuyang Bai, Zeyu Hu, Xinge Zhu, Qingqiu Huang, Yilun Chen, Hongbo Fu, and Chiew-Lan Tai. Transfusion: Robust lidar-camera fusion for 3d object detection with transformers. In CVPR, 2022. 2 +[3] Connelly Barnes, Eli Shechtman, Adam Finkelstein, and Dan B Goldman. PatchMatch: A randomized correspondence algorithm for structural image editing. 2009. 5 +[4] Ioan Andrei Barsan, Shenlong Wang, Andrei Pokrovsky, and Raquel Urtasun. Learning to localize using a lidar intensity map. In CoRL, 2018. 2 +[5] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. In ICLR, 2019. 2 +[6] Holger Caesar, Varun Bankiti, Alex H. Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In CVPR, 2020. 6 +[7] Sergio Casas, Wenjie Luo, and Raquel Urtasun. Intentnet: Learning to predict intention from raw sensor data. In CoRL, 2018. 2 +[8] Sergio Casas, Abbas Sadat, and Raquel Urtasun. Mp3: A unified model to map, perceive, predict and plan. In CVPR, 2021. 2 +[9] Huiwen Chang, Han Zhang, Lu Jiang, Ce Liu, and William T. Freeman. Maskgit: Masked generative image transformer. In CVPR, 2022. 2, 3, 5 +[10] Bowen Cheng, Alexander G. Schwing, and Alexander Kirillov. Per-pixel classification is not all you need for semantic segmentation. In NeurIPS, 2021. 2 +[11] Kashyap Chitta, Aditya Prakash, and Andreas Geiger. Neat: Neural attention fields for end-to-end autonomous driving. In CVPR, 2021. 2 +[12] Min Jin Chong and David Forsyth. Jojogan: One shot face stylization. In ECCV, 2022. 3 +[13] Laurene Claussmann, Marc Revilloud, Dominique Gruyer, and Sébastien Glaser. A review of motion planning for highway autonomous driving. 2020. 2 +[14] Prafulla Dhariwal and Alex Nichol. Diffusion models beat gans on image synthesis. In NeurIPS, 2021. 2 +[15] Laurent Dinh, David Krueger, and Yoshua Bengio. Nice: Non-linear independent components estimation. In ICLR (Workshop), 2014. 2 +[16] Shivam Duggal, Shenlong Wang, Wei-Chiu Ma, Rui Hu, and Raquel Urtasun. Deepruner: Learning efficient stereo matching via differentiable patchmatch. In ICCV, 2019. 3 +[17] Alexei A. Efros and William T. Freeman. Image quilting for texture synthesis and transfer. In SIGGRAPH, 2001. 5 +[18] Patrick Esser, Robin Rombach, and Björn Ommer. Taming transformers for high-resolution image synthesis. In CVPR, 2021. 2, 3, 4, 5 +[19] W.T. Freeman and E.C. Pasztor. Learning low-level vision. In CVPR, 1999. 3 + +[20] Ian J. Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. In NeurIPS, 2014. 2 +[21] Nikhil Gosala and Abhinav Valada. Bird's-eye-view panoptic segmentation using monocular frontal view images. 2022. 2 +[22] Chuan Guo, Geoff Pleiss, Yu Sun, and Kilian Q. Weinberger. On calibration of modern neural networks. In ICML, 2017. 6 +[23] Agrim Gupta, Justin Johnson, Li Fei-Fei, Silvio Savarese, and Alexandre Alahi. Social gan: Socially acceptable trajectories with generative adversarial networks. In CVPR, 2018. 2 +[24] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. In NeurIPS, 2020. 2 +[25] Ari Holtzman, Jan Buys, Li Du, Maxwell Forbes, and Yejin Choi. The curious case of neural text degeneration. In ICLR, 2020. 4 +[26] Anthony Hu, Zak Murez, Nikhil Mohan, Sofia Dudas, Jeffrey Hawke, Vijay Badrinarayanan, Roberto Cipolla, and Alex Kendall. FIERY: Future instance segmentation in bird's-eye view from surround monocular cameras. In ICCV, 2021. 2 +[27] Junjie Huang, Guan Huang, Zheng Zhu, and Dalong Du. BEVDet: High-Performance Multi-Camera 3D Object Detection in Bird-Eye-View. arXiv preprint arXiv:2112.11790, 2021. 2 +[28] Phillip Isola, Jun-Yan Zhu, Tinghui Zhou, and Alexei A. Efros. Image-to-image translation with conditional adversarial networks. In CVPR, 2017. 2, 3 +[29] Eric Jang, Shixiang Gu, and Ben Poole. Categorical Reparaterization with Gumbel-Softmax. In ICLR, 2017. 5 +[30] Andrej Karpathy. Mingpt. https://github.com/karpathy/minGPT, 2022.8 +[31] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In CVPR, 2019. 2 +[32] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. 8 +[33] Diederik P. Kingma and Prafulla Dhariwal. Glow: Generative flow with invertible 1x1 convolutions. In NeurIPS, 2018. 2 +[34] Diederik P Kingma and Max Welling. Auto-encoding variational bayes. In ICLR, 2014. 2 +[35] Philipp Kähenbuhl and Vladlen Koltun. Efficient inference in fully connected crfs with gaussian edge potentials. In NeurIPS, 2011. 3 +[36] Ananya Kumar, Percy Liang, and Tengyu Ma. Verified uncertainty calibration. In NeurIPS, 2019. 6 +[37] Markus Kängsepp and Meelis Kull. Calibrated perception uncertainty across objects and regions in bird's-eye-view. In NeurIPS (Workshop), 2022. 2 +[38] Alex H. Lang, Sourabh Vora, Holger Caesar, Lubing Zhou, Jiong Yang, and Oscar Beijbom. Pointpillars: Fast encoders for object detection from point clouds. In CVPR, 2019. 2, 6, 8 +[39] Jesse Levinson, Jake Askeland, Jan Becker, Jennifer Dolson, David Held, Soeren Kammel, J. Zico Kolter, Dirk Langer, Oliver Pink, Vaughan Pratt, Michael Sokolsky, Ganymed Stanek, David Stavens, Alex Teichman, Moritz Werling, and + +Sebastian Thrun. Towards fully autonomous driving: Systems and algorithms. In IV, 2011. 2 +[40] Jesse Levinson and Sebastian Thrun. Robust vehicle localization in urban environments using probabilistic maps. In ICRA, 2010. 2 +[41] Daiqing Li, Junlin Yang, Karsten Kreis, Antonio Torralba, and Sanja Fidler. Semantic segmentation with generative models: Semi-supervised learning and strong out-of-domain generalization. In CVPR, 2021. 3 +[42] Qi Li, Yue Wang, Yilun Wang, and Hang Zhao. Hdmapnet: An online hd map construction and evaluation framework. In ICRA, 2022. 2 +[43] Ming Liang, Bin Yang, Rui Hu, Yun Chen, Renjie Liao, Song Feng, and Raquel Urtasun. Learning lane graph representations for motion forecasting. In ECCV, 2020. 2 +[44] Ming Liang, Bin Yang, Shenlong Wang, and Raquel Urtasun. Deep continuous fusion for multi-sensor 3d object detection. In ECCV, 2018. 2 +[45] Andrew Liu, Richard Tucker, Varun Jampani, Ameesh Makadia, Noah Snavely, and Angjoo Kanazawa. Infinite nature: Perpetual view generation of natural scenes from a single image. In ICCV, 2021. 5 +[46] Yingfei Liu, Tiancai Wang, Xiangyu Zhang, and Jian Sun. Petr: Position embedding transformation for multi-view 3d object detection. In ECCV, 2022. 2 +[47] Yicheng Liu, Yuan Yuantian, Yue Wang, Yilun Wang, and Hang Zhao. Vectormapnet: End-to-end vectorized hd map learning. arXiv preprint arXiv:2206.08920, 2022. 2 +[48] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin Transformer: Hierarchical Vision Transformer using Shifted Windows. In ICCV, 2021. 4 +[49] Zhijian Liu, Haotian Tang, Alexander Amini, Xinyu Yang, Huizi Mao, Daniela Rus, and Song Han. Bevfusion: Multi-task multi-sensor fusion with unified bird's-eye view representation. In ICRA, 2023. 1, 2, 3, 4, 6, 8, 9 +[50] W. Luo, B. Yang, and R. Urtasun. Fast and furious: Real time end-to-end 3d detection, tracking and motion forecasting with a single convolutional net. In CVPR, 2018. 2 +[51] Jiageng Mao, Yujing Xue, Minzhe Niu, Haoyue Bai, Jiashi Feng, Xiaodan Liang, Hang Xu, and Chunjing Xu. Voxel transformer for 3d object detection. In CVPR, 2021. 2 +[52] Gellert Mattyus, Shenlong Wang, Sanja Fidler, and Raquel Urtasun. Hd maps: Fine-grained road segmentation by parsing ground and aerial images. In CVPR, 2016. 2 +[53] Andrew Ng and Michael Jordan. On discriminative vs. generative classifiers: A comparison of logistic regression and naive bayes. In NeurIPS, 2001. 2 +[54] Taesung Park, Jun-Yan Zhu, Oliver Wang, Jingwan Lu, Eli Shechtman, Alexei A. Efros, and Richard Zhang. Swapping autoencoder for deep image manipulation. In NeurIPS, 2020. 3 +[55] Niki Parmar, Ashish Vaswani, Jakob Uszkoreit, Lukasz Kaiser, Noam Shazeer, Alexander Ku, and Dustin Tran. Image transformer. In ICML, 2018. 2 +[56] Jonah Philion and Sanja Fidler. Lift, splat, shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3d. In ECCV, 2020. 1, 2, 3, 4, 6, 8 + +[57] Aditya Prakash, Kashyap Chitta, and Andreas Geiger. Multimodal fusion transformer for end-to-end autonomous driving. In CVPR, 2021. 2 +[58] Marc'Aurelio Ranzato, Joshua Sussekind, Volodymyr Mnih, and Geoffrey Hinton. On deep generative models with applications to recognition. In CVPR, 2011. 2 +[59] Cody Reading, Ali Harakeh, Julia Chae, and Steven L Waslander. Categorical depth distribution network for monocular 3d object detection. In CVPR, 2021. 2 +[60] Thomas Roddick, Alex Kendall, and Roberto Cipolla. Orthographic feature transform for monocular 3d object detection. In BMVC, 2019. 2, 6, 8 +[61] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In CVPR, 2022. 3 +[62] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In MICCAI, 2015. 2 +[63] S. Roth and M.J. Black. Fields of experts: a framework for learning image priors. In CVPR, 2005. 3 +[64] Tim Salzmann, Boris Ivanovic, Punarjay Chakravarty, and Marco Pavone. Trajectory: Dynamically-feasible trajectory forecasting with heterogeneous data. In ECCV, 2020. 2 +[65] Yuan Shen, Wei-Chiu Ma, and Shenlong Wang. SGAM: Building a virtual 3d world through simultaneous generation and mapping. In NeurIPS, 2022. 5 +[66] Jianbo Shi and J. Malik. Normalized cuts and image segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 22(8):888-905, 2000. 3 +[67] Shaoshuai Shi, Li Jiang, Jiajun Deng, Zhe Wang, Chaoxu Guo, Jianping Shi, Xiaogang Wang, and Hongsheng Li. Pvrccnn++: Point-voxel feature set abstraction with local vector representation for 3d object detection. Springer, 2023. 2 +[68] Shaoshuai Shi, Xiaogang Wang, and Hongsheng Li. Pointr-cnn: 3d object proposal generation and detection from point cloud. In CVPR, 2019. 2 +[69] Nitish Srivastava and Russ R Salakhutdinov. Multimodal learning with deep boltzmann machines. In NeurIPS, 2012. 2 +[70] Deqing Sun, Stefan Roth, and Michael J. Black. Secrets of optical flow estimation and their principles. In CVPR, 2010. 3 +[71] Sebastian Thrun, Mike Montemerlo, Hendrik Dahlkamp, David Stavens, Andrei Aron, James Diebel, Philip Fong, John Gale, Morgan Halpenny, Gabriel Hoffmann, Kenny Lau, Celia Oakley, Mark Palatucci, Vaughan Pratt, Pascal Stang, Sven Strohband, Cedric Dupont, Lars-Erik Jendrossek, Christian Koelen, Charles Markey, Carlo Rummel, Joe van Niekerk, Eric Jensen, Philippe Alessandrini, Gary Bradski, Bob Davies, Scott Ettinger, Adrian Kaehler, Ara Nefian, and Pamela Mahoney. Stanley: The Robot That Won the DARPA Grand Challenge. 2007. 2 +[72] Hung-Yu Tseng, Lu Jiang, Ce Liu, Ming-Hsuan Yang, and Weilong Yang. Regularizing generative adversarial networks under limited data. In CVPR, 2021. 2 +[73] Arash Vahdat and Jan Kautz. Nvae: A deep hierarchical variational autoencoder. In NeurIPS, 2020. 2 + +[74] Aaron van den Oord, Oriol Vinyals, and Koray Kavukcuoglu. Neural discrete representation learning. In NeurIPS, 2017. 2 +[75] Sourabh Vora, Alex H. Lang, Bassam Helou, and Oscar Bei-jbom. Pointpainting: Sequential fusion for 3d object detection. In CVPR, 2020. 2, 6, 8 +[76] Enze Xie, Zhiding Yu, Daquan Zhou, Jonah Philion, Anima Anandkumar, Sanja Fidler, Ping Luo, and Jose M. Alvarez. $\mathbf{M}^2$ bev: Multi-camera joint 3d detection and segmentation with unified birds-eye view representation. arXiv preprint arXiv:2204.05088, 2022. 2, 3 +[77] Koichiro Yamaguchi, Tamir Hazan, David McAllester, and Raquel Urtasun. Continuous markov random fields for robust stereo estimation. In ECCV, 2012. 3 +[78] Yan Yan, Yuxing Mao, and Bo Li. Second: Sparsely embedded convolutional detection. Sensors, 18(10), 2018. 4 +[79] R. A. Yeh, C. Chen, T. Lim, A. G. Schwing, M. Hasegawa-Johnson, and M. N. Do. Semantic image inpainting with deep generative models. In CVPR, 2017. 2 +[80] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Center-based 3d object detection and tracking. In CVPR, 2021. 1, 2, 3, 4, 6, 8, 9 +[81] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Multi-modal virtual point 3d detection. In NeurIPS, 2021. 2, 3, 6, 8 +[82] Wenyuan Zeng, Shenlong Wang, Renjie Liao, Yun Chen, Bin Yang, and Raquel Urtasun. Dsdnet: Deep structured self-driving network. In ECCV, 2020. 2 +[83] Han Zhang, Ian Goodfellow, Dimitris Metaxas, and Augustus Odena. Self-attention generative adversarial networks. In ICML, 2019. 2 +[84] Hang Zhao, Jiyang Gao, Tian Lan, Chen Sun, Benjamin Sapp, Balakrishnan Varadarajan, Yue Shen, Yi Shen, Yuning Chai, Cordelia Schmid, Congcong Li, and Dragomir Anguelov. Tnt: Target-driven trajectory prediction. In CoRL, 2020. 2 +[85] Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, and Jiaya Jia. Pyramid scene parsing network. In CVPR, 2017. 2 +[86] Shuai Zheng, Sadeep Jayasumana, Bernardino Romero-Paredes, Vibhav Vineet, Zhizhong Su, Dalong Du, Chang Huang, and Philip H. S. Torr. Conditional random fields as recurrent neural networks. In ICCV, 2015. 3 +[87] Brady Zhou and Philipp Krahenbuhl. Cross-view transformers for real-time map-view semantic segmentation. In CVPR, 2022. 2 +[88] Jun-Yan Zhu, Taesung Park, Phillip Isola, and Alexei A Efros. Unpaired image-to-image translation using cycle-consistent adversarial networks. In ICCV, 2017. 3 +[89] Song Chun Zhu, Yingnian Wu, and D. Mumford. Frame: filters, random fields, and minimax entropy towards a unified theory for texture modeling. In CVPR, 1996. 3 \ No newline at end of file diff --git a/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/images.zip b/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..53fbfa569c9b35a21fbb003e7e2ccfe094a09735 --- /dev/null +++ b/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:d19599355267ff07f902606708662835fb450601b2353183c1406e1d18534280 +size 750344 diff --git a/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/layout.json b/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..f38592ad4033d5216ba571c47999e0b78591b18d --- /dev/null +++ b/2023/MapPrior_ Bird's-Eye View Map Layout Estimation with Generative Models/layout.json @@ -0,0 +1,12382 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 60, + 103, + 533, + 120 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 103, + 533, + 120 + ], + "spans": [ + { + "bbox": [ + 60, + 103, + 533, + 120 + ], + "type": "text", + "content": "MapPrior: Bird's-Eye View Map Layout Estimation with Generative Models" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 130, + 142, + 462, + 173 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 130, + 142, + 462, + 173 + ], + "spans": [ + { + "bbox": [ + 130, + 142, + 462, + 173 + ], + "type": "text", + "content": "Xiyue Zhu1 Vlas Zyrianov1 Zhijian Liu2 Shenlong Wang1 \n1University of Illinois at Urbana-Champaign 2MIT" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 217, + 186, + 375, + 199 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 217, + 186, + 375, + 199 + ], + "spans": [ + { + "bbox": [ + 217, + 186, + 375, + 199 + ], + "type": "text", + "content": "https://mapprior.github.io" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 227, + 192, + 239 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 227, + 192, + 239 + ], + "spans": [ + { + "bbox": [ + 143, + 227, + 192, + 239 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 252, + 290, + 445 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 252, + 290, + 445 + ], + "spans": [ + { + "bbox": [ + 46, + 252, + 290, + 445 + ], + "type": "text", + "content": "Despite tremendous advancements in bird's-eye view (BEV) perception, existing models fall short in generating realistic and coherent semantic map layouts, and they fail to account for uncertainties arising from partial sensor information (such as occlusion or limited coverage). In this work, we introduce MapPrior, a novel BEV perception framework that combines a traditional discriminative BEV perception model with a learned generative model for semantic map layouts. Our MapPrior delivers predictions with better accuracy, realism and uncertainty awareness. We evaluate our model on the large-scale nuScenes benchmark. At the time of submission, MapPrior outperforms the strongest competing method, with significantly improved MMD and ECE scores in camera- and LiDAR-based BEV perception. Furthermore, our method can be used to perpetually generate layouts with unconditional sampling." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 466, + 128, + 478 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 466, + 128, + 478 + ], + "spans": [ + { + "bbox": [ + 47, + 466, + 128, + 478 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 486, + 288, + 570 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 486, + 288, + 570 + ], + "spans": [ + { + "bbox": [ + 46, + 486, + 288, + 570 + ], + "type": "text", + "content": "Accurately understanding the surrounding environment of autonomous vehicles is crucial to guarantee the safety of riders and other traffic participants. Among various perception approaches, Bird's-Eye View (BEV) perception has drawn significant attention in recent years thanks to its capacity to densely model scene layouts and its tight coupling with downstream planning [80, 56, 49]." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 570, + 288, + 701 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 288, + 701 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 288, + 701 + ], + "type": "text", + "content": "Existing perception models encounter two challenges. The first challenge pertains to the limitations of observations, particularly in distant or occluded regions, resulting in inaccurate predictions. This may manifest in choppy, out-of-distribution, or missing map elements. The second challenge is that most existing models do not consider uncertainty and diversity in possible road layouts. Taking Fig. 1 as an example, the state-of-the-art LiDAR perception model [80] generates incoherent lane markings and sidewalks with massive gaps and cannot quantify the uncertainty and multi-modality as it only produces a single prediction per input." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 59, + 701, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 701, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 59, + 701, + 287, + 714 + ], + "type": "text", + "content": "This paper presents MapPrior, a novel BEV perception" + } + ] + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 310, + 226, + 545, + 392 + ], + "blocks": [ + { + "bbox": [ + 310, + 226, + 545, + 392 + ], + "lines": [ + { + "bbox": [ + 310, + 226, + 545, + 392 + ], + "spans": [ + { + "bbox": [ + 310, + 226, + 545, + 392 + ], + "type": "image", + "image_path": "75dd5875b84a2d5682ff0c4150c54471eab0faa1d3c6591af1a4bac819ae2778.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 399, + 548, + 483 + ], + "lines": [ + { + "bbox": [ + 304, + 399, + 548, + 483 + ], + "spans": [ + { + "bbox": [ + 304, + 399, + 548, + 483 + ], + "type": "text", + "content": "Figure 1: Existing predictive BEV perception models do not provide realistic scene structures (e.g., the lane and sidewalks have gaps and are not straight). In contrast, our MapPrior is able to accurately recover the layout with a learned prior. These results are validated with a quantitative comparison, showing our method's superior accuracy, realism and uncertainty awareness." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 508, + 547, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 508, + 547, + 628 + ], + "spans": [ + { + "bbox": [ + 304, + 508, + 547, + 628 + ], + "type": "text", + "content": "method that is accurate, realistic, and uncertainty-aware. At the heart of our method is a novel combination of the standard discriminative BEV perception model with a learned deep generative traffic layout prior. Incorporating generative modeling in this predictive task attempts to address the two aforementioned challenges – modeling the data distribution improves realism, and using a sampling process allows generating multiple realistic predictions. Combining our generative model with a discriminative perception model ensures that our method retains a strong predictive ability." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 630, + 548, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 548, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 548, + 713 + ], + "type": "text", + "content": "Our approach comprises two steps, namely the prediction and generative steps. In the prediction step, we use an off-the-shelf BEV perception model [49] to make an initial layout estimate of the traffic scene from sensory input. In the generative step, we use our MapPrior model and initial estimate to sample one or multiple refined layouts. We perform sampling in a learned discrete latent space using a condi-" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8228" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 288, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 288, + 144 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 288, + 144 + ], + "type": "text", + "content": "tional transformer that is provided with the initial prediction. Finally, the generated tokens are passed into a decoder to output the final layout prediction, which is diverse, realistic, and coherent with the input. The encoder, decoder, and codebook of the MapPrior are trained from real-world map data in an unsupervised way." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 144, + 288, + 264 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 144, + 288, + 264 + ], + "spans": [ + { + "bbox": [ + 46, + 144, + 288, + 264 + ], + "type": "text", + "content": "We benchmark our method on the nuScenes dataset against various state-of-the-art BEV perception methods with varying modalities. Our results show that MapPrior outperforms existing methods in terms of accuracy (as reflected by mean intersection-over-union), realism (as reflected by maximum-mean discrepancy), and uncertainty awareness (as reflected by expected calibration error). Furthermore, we demonstrate the unconditional generation capabilities of MapPrior by generating a realistic and consistent HD map of a " + }, + { + "bbox": [ + 46, + 144, + 288, + 264 + ], + "type": "inline_equation", + "content": "30\\mathrm{km}" + }, + { + "bbox": [ + 46, + 144, + 288, + 264 + ], + "type": "text", + "content": "-long road." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 274, + 134, + 286 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 274, + 134, + 286 + ], + "spans": [ + { + "bbox": [ + 47, + 274, + 134, + 286 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 294, + 288, + 426 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 294, + 288, + 426 + ], + "spans": [ + { + "bbox": [ + 46, + 294, + 288, + 426 + ], + "type": "text", + "content": "Self-driving perception aims to interpret sensory input and establish a representation of the surrounding environment from onboard sensors. It is a critical component for ensuring the safety and efficiency of autonomous vehicles, and various methods have been proposed to improve accuracy and robustness [71, 39]. Traditional approaches for self-driving perception involve multiple (isolated) subtasks, such as localizing against a pre-scanned environment [40, 4], object detection and tracking [38, 80, 68, 44, 50], image segmentation [62, 85, 10] and trajectory prediction [23, 64, 84, 43, 7, 82]." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 426, + 288, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 426, + 288, + 533 + ], + "spans": [ + { + "bbox": [ + 46, + 426, + 288, + 533 + ], + "type": "text", + "content": "Recently, there has been a growing interest in a unified Bird's Eye View (BEV) perception, both in academia [60, 87, 56, 76, 8, 50] and industry [26]. This approach aims to produce a top-down semantic layout of the traffic scene from sensory input, which is efficient, informative, and compact. Notably, the top-down layout is closely linked to downstream 2D motion planning for wheeled robots, making BEV perception particularly suitable for self-driving navigation." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 534, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 534, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 534, + 288, + 714 + ], + "type": "text", + "content": "Various BEV perception modules have been studied in robotics and computer science to improve perception accuracy. These approaches typically take LiDAR [80, 38, 51, 67], multi-view camera [60, 87, 56, 76, 11, 46, 26, 59, 21], or both [81, 75, 49, 2, 57] as input, and output segmentations for road elements and detections for dynamic traffic participants like cars, cyclists or pedestrians. The majority of these methods are supervised and rely on predictive networks like CNNs [59, 67, 80, 38, 44, 60, 56] and transformers [2, 57, 11, 46, 51, 87, 21, 26, 27]. Despite their success, there are still unresolved challenges. For example, real-world traffic layouts are highly structured, with straight lane marks, strong topological relationships, and sharp road element boundaries. But such structures have proven difficult to preserve in the BEV perception output map, even" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": "with state-of-the-art methods, as shown in Fig. 1. This can harm the realism of perception output and the practicality of the resulting map for motion planning. Additionally, most networks make a single layout estimation without diversity or calibrated uncertainty, leaving the autonomy vulnerable to catastrophic failure." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 144, + 547, + 263 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 144, + 547, + 263 + ], + "spans": [ + { + "bbox": [ + 304, + 144, + 547, + 263 + ], + "type": "text", + "content": "HDMapNet [42], VectorMapNet [47], and others [52, 8] have been proposed to address the issue of layout structure by introducing a vectorized output map format with implicitly structured priors. However, this approach fails to account for all layer types and still produces significant artifacts in regions with limited observations. Very recently, calibrated confidence scores have been investigated to address the aforementioned uncertainty issue [37, 13], but the inherent multi-modal uncertainty in BEV perception remains under-explored." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 264, + 547, + 337 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 264, + 547, + 337 + ], + "spans": [ + { + "bbox": [ + 304, + 264, + 547, + 337 + ], + "type": "text", + "content": "In contrast, our approach leverages generative modeling as a map prior, which encodes the rich structure of the traffic scene. Our conditional generative modeling also allows us to sample multiple diverse outputs for the same input. Consequently, our results are more accurate and realistic with better multi-modal uncertainty modeling." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 350, + 547, + 615 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 350, + 547, + 615 + ], + "spans": [ + { + "bbox": [ + 304, + 350, + 547, + 615 + ], + "type": "text", + "content": "Generative models. Our approach to generative BEV perception involves learning a map prior and performing conditional sampling using deep generative models. Generative models learn to capture the underlying structure of the data distribution and create new, diverse samples. Several well-known approaches include VAEs (variational autoencoders) [34, 73], which use variational inference to learn a latent space model, and autoregressive models [55], which decompose the generation problem into simpler conditional generation tasks. GANs (generative adversarial networks) [20, 83, 1, 31, 28, 72, 5] use an adversarial loss to train networks to convert noise into samples. Flow-based models [33, 15] exploit an invertible process to sample from a proposal distribution. Recently, diffusion models [14, 24] have been developed that generate samples through a denoising-diffusion process. Our method leverages vector-quantized generative models [74, 18, 9], which use a discrete-valued latent space representation that is powerful, structure-preserving, and efficient for conditional sampling. Specifically, we build our map prior on top of this approach to capture the discrete structure of the map data and generate high-quality samples." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": "Generative approach for vision. Our approach belongs to the broader category of generative modeling approaches in computer vision [79, 53, 58, 69], which includes Markov random fields (MRFs), factor graphs, energy-based models, deep generative models, among others. These practices date back to the 1970s. In contrast to discriminative or predictive approaches, generative approaches often tackle the task" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8229" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 70, + 547, + 200 + ], + "blocks": [ + { + "bbox": [ + 49, + 70, + 547, + 200 + ], + "lines": [ + { + "bbox": [ + 49, + 70, + 547, + 200 + ], + "spans": [ + { + "bbox": [ + 49, + 70, + 547, + 200 + ], + "type": "image", + "image_path": "ea864e38c632ef366352e51153a39bf086dcb0821989689642279a77c040e984.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 213, + 547, + 251 + ], + "lines": [ + { + "bbox": [ + 46, + 213, + 547, + 251 + ], + "spans": [ + { + "bbox": [ + 46, + 213, + 547, + 251 + ], + "type": "text", + "content": "Figure 2: MapPrior first makes use of an off-the-shelf perception model to generate an initial noisy estimate from the sensory input. It then encodes the noisy estimate into a discrete latent code using a generative encoder and generates various samples through a transformer-based controlled synthesis. Finally, MapPrior decodes these samples into outputs with a decoder." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 270, + 290, + 402 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 270, + 290, + 402 + ], + "spans": [ + { + "bbox": [ + 46, + 270, + 290, + 402 + ], + "type": "text", + "content": "as a marginal sampling or MAP inference problem, which is more effective at utilizing strong prior knowledge and modeling uncertainty. Representative works can be seen in low-level vision [19, 89], optical flow [70, 63], and image segmentation [66, 35, 86]. Generative approaches with conditional sampling have often been investigated in vision tasks involving multimodality or uncertainty, such as image editing [88, 28, 12, 54], image segmentation [41] and stereo estimation [16, 77]. However, few studies have explored their use in self-driving perception, despite its inherent multimodal uncertainty nature." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 414, + 115, + 427 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 414, + 115, + 427 + ], + "spans": [ + { + "bbox": [ + 47, + 414, + 115, + 427 + ], + "type": "text", + "content": "3. Approach" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 434, + 289, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 434, + 289, + 567 + ], + "spans": [ + { + "bbox": [ + 46, + 434, + 289, + 567 + ], + "type": "text", + "content": "The objective of this research is to develop a method that can generate a precise, realistic, and uncertainty-aware map layout from sensory input in one or a few modalities. To achieve this, we introduce a new framework named MapPrior that combines the predictive capability of discriminative models with the capacity of generative models to capture structures and uncertainties. We present a two-stage conditional sampling framework to explain our approach and detail the implementation of each module. Additionally, we discuss our design decisions, the learning process, and how our approach relates to previous methods." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 575, + 115, + 586 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 575, + 115, + 586 + ], + "spans": [ + { + "bbox": [ + 47, + 575, + 115, + 586 + ], + "type": "text", + "content": "3.1. Overview" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": "**Formulation.** We formulate the probabilistic BEV perception problem as a conditional sampling task. Given the sensory input " + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{x} \\in \\mathcal{X}" + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": " (which could be from a camera, LiDAR or multiple sensors), we aim to find one or multiple plausible traffic layouts " + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{y} \\in \\mathcal{Y}" + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": " from the top-down bird's-eye view. The traffic layout " + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": " is a multi-layer binary map centered at the ego vehicle. Conventional methods [49, 80, 56, 81, 76] rely on a deterministic predictive network " + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{y} = f_{\\theta}(\\mathbf{x})" + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": " to provide a single output estimation. We propose, instead, to use a generative vector-quantized latent space model to model" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 270, + 547, + 331 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 270, + 547, + 331 + ], + "spans": [ + { + "bbox": [ + 304, + 270, + 547, + 331 + ], + "type": "text", + "content": "the uncertainty and diversity. Specifically, we aim to design a conditional probability model " + }, + { + "bbox": [ + 304, + 270, + 547, + 331 + ], + "type": "inline_equation", + "content": "p_{\\theta}(\\mathbf{y}|\\mathbf{x})" + }, + { + "bbox": [ + 304, + 270, + 547, + 331 + ], + "type": "text", + "content": " that can sample our desired output " + }, + { + "bbox": [ + 304, + 270, + 547, + 331 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 304, + 270, + 547, + 331 + ], + "type": "text", + "content": " from a distribution. This allows us to explicitly model uncertainty and generate multiple plausible traffic layouts." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 349, + 548, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 349, + 548, + 529 + ], + "spans": [ + { + "bbox": [ + 304, + 349, + 548, + 529 + ], + "type": "text", + "content": "Motivation. Intuitively speaking, the objective of a predictive perception model is to produce a coherent semantic layout that best represents the sensory input. However, this training objective does not necessarily optimize for structure preservation or realism. For example, minor defects in lane markers might not significantly affect cross-entropy, but could drastically impact downstream modules due to topological changes. On the other hand, a generative prior model, such as a GAN, is trained to capture realism in structures. The advantage of such a model is that it can be trained on HD map collections, without paired data, in an unsupervised manner. This insight inspires our proposed solution, which combines a predictive model with a generative model to tackle the conditional sampling task with both coherence and realism in mind." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 539, + 373, + 550 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 539, + 373, + 550 + ], + "spans": [ + { + "bbox": [ + 306, + 539, + 373, + 550 + ], + "type": "text", + "content": "3.2. Inference" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "content": "In our framework, the distribution " + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "inline_equation", + "content": "p_{\\theta}(\\mathbf{y}|\\mathbf{x})" + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "content": " is defined implicitly using a latent model " + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{z}" + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "content": ". The framework comprises of a predictive stage and a generative stage. During the predictive stage, the perception module " + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "inline_equation", + "content": "F(\\mathbf{x})" + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "content": " generates an initial noisy estimate " + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{y}'" + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "content": " for input " + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "content": ". For the generative stage, we take inspiration from recent successful techniques in vector-quantized generation [18, 9, 61] for conditional sampling and use a VQGAN-like model to generate multiple realistic samples. To achieve this, we encode the noisy estimate " + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{y}'" + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "content": " into a discrete latent code " + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{z}'" + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "content": " using a generative encoder " + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "inline_equation", + "content": "E(\\mathbf{y}')" + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "content": ". This latent code " + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{z}'" + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "content": " and the sensory input " + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "content": " then guide the generative synthesis process through a transformer-based controlled synthesis in the latent space, producing various" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8230" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 71, + 288, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 71, + 288, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 71, + 288, + 120 + ], + "type": "text", + "content": "samples " + }, + { + "bbox": [ + 46, + 71, + 288, + 120 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{z}^{(k)}\\sim p(\\mathbf{z}|\\mathbf{z}',\\mathbf{x})\\}" + }, + { + "bbox": [ + 46, + 71, + 288, + 120 + ], + "type": "text", + "content": ". Finally, these samples are decoded into multiple output samples using a decoder " + }, + { + "bbox": [ + 46, + 71, + 288, + 120 + ], + "type": "inline_equation", + "content": "G(\\cdot)" + }, + { + "bbox": [ + 46, + 71, + 288, + 120 + ], + "type": "text", + "content": ": " + }, + { + "bbox": [ + 46, + 71, + 288, + 120 + ], + "type": "inline_equation", + "content": "\\mathbf{y}^{(k)} = G(\\mathbf{z}^{(k)})" + }, + { + "bbox": [ + 46, + 71, + 288, + 120 + ], + "type": "text", + "content": ", which provides our final layout estimation samples. Fig. 2 depicts the overall inference framework." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 134, + 289, + 386 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 134, + 289, + 386 + ], + "spans": [ + { + "bbox": [ + 46, + 134, + 289, + 386 + ], + "type": "text", + "content": "Predictive stage. The predictive stage aims to establish reliable initial layout estimation that can act as a guiding control during the conditional sampling stage. To achieve this, we have incorporated a predictive sensory backbone, VoxelNet [78, 80] for LiDAR and Swin Transformer [48] for multi-view camera inputs. The sensory backbone networks first extract features from the sensory space and then project them into bird's eye view features. For the LiDAR input, a 3D convolution backbone is utilized as a feature extractor, and the LiDAR features are flattened along the height dimension to project them to BEV. In contrast, for the camera input, a hierarchical transformer is used as a feature extractor for each view, and monocular depth estimation and view transformation are applied to project the features to BEV. The predictive model employs a convolutional segmentation head to generate the layout estimates, denoted by " + }, + { + "bbox": [ + 46, + 134, + 289, + 386 + ], + "type": "inline_equation", + "content": "\\mathbf{y}' = F(\\mathbf{x})" + }, + { + "bbox": [ + 46, + 134, + 289, + 386 + ], + "type": "text", + "content": ". It should be noted that the resulting BEV map achieves a reasonable intersection-over-union score (IoU). However, as Fig. 1 highlights, the model suffers from unrealistic structures, missing road elements, and noise, particularly in regions with limited observations." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 400, + 288, + 507 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 400, + 288, + 507 + ], + "spans": [ + { + "bbox": [ + 46, + 400, + 288, + 507 + ], + "type": "text", + "content": "Generative stage. To enhance the quality and diversity of our perception, we incorporate a generative map prior in the second stage for conditional generation. The generative map prior is built on a VQGAN architecture [18], which consists of three learnable components: the encoder " + }, + { + "bbox": [ + 46, + 400, + 288, + 507 + ], + "type": "inline_equation", + "content": "E" + }, + { + "bbox": [ + 46, + 400, + 288, + 507 + ], + "type": "text", + "content": ", the decoder " + }, + { + "bbox": [ + 46, + 400, + 288, + 507 + ], + "type": "inline_equation", + "content": "G" + }, + { + "bbox": [ + 46, + 400, + 288, + 507 + ], + "type": "text", + "content": ", and the codebook " + }, + { + "bbox": [ + 46, + 400, + 288, + 507 + ], + "type": "inline_equation", + "content": "\\mathcal{C} = \\{\\mathbf{c}_j\\}" + }, + { + "bbox": [ + 46, + 400, + 288, + 507 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 46, + 400, + 288, + 507 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 46, + 400, + 288, + 507 + ], + "type": "text", + "content": " being the code index. The encoder transforms a traffic layout into a latent feature map, where each element of the spatial map is chosen from one of the codes in the codebook as follows:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 86, + 516, + 287, + 538 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 86, + 516, + 287, + 538 + ], + "spans": [ + { + "bbox": [ + 86, + 516, + 287, + 538 + ], + "type": "interline_equation", + "content": "\\mathbf {z} _ {t} (\\mathbf {y}) = \\underset {\\mathbf {c} _ {j} \\in \\mathcal {Z}} {\\arg \\max } \\| \\mathbf {c} _ {j} - E _ {t} (\\mathbf {y}) \\| _ {2} ^ {2}, \\quad \\forall t \\tag {1}", + "image_path": "985db4f58b42c3026d48f12933a682a0def400bcbbe06ac53566cda901b003fa.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 546, + 287, + 630 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 546, + 287, + 630 + ], + "spans": [ + { + "bbox": [ + 46, + 546, + 287, + 630 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 546, + 287, + 630 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 546, + 287, + 630 + ], + "type": "text", + "content": " is the " + }, + { + "bbox": [ + 46, + 546, + 287, + 630 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 546, + 287, + 630 + ], + "type": "text", + "content": "-th entry of the feature map " + }, + { + "bbox": [ + 46, + 546, + 287, + 630 + ], + "type": "inline_equation", + "content": "\\mathbf{z}" + }, + { + "bbox": [ + 46, + 546, + 287, + 630 + ], + "type": "text", + "content": ". The decoder then transforms the latent code back to the layout map space: " + }, + { + "bbox": [ + 46, + 546, + 287, + 630 + ], + "type": "inline_equation", + "content": "G(\\mathbf{z}(\\mathbf{y}))" + }, + { + "bbox": [ + 46, + 546, + 287, + 630 + ], + "type": "text", + "content": ". Sampling from this prior can be done by randomly drawing a latent code and decoding it into a layout map. The discrete-valued auto-encoder architecture greatly regularizes the output space in a structured manner, preventing it from producing unrealistic reconstructions, as shown in Fig 1." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "text", + "content": "During conditional sampling at inference, we first encode the noisy estimate " + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{y}'" + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "text", + "content": " into a discrete latent code " + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}'" + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "text", + "content": " using a generative encoder " + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "inline_equation", + "content": "E" + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "text", + "content": ". This latent code " + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}'" + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "text", + "content": " and the sensory input " + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "text", + "content": " are then used as guidance by a transformer " + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "inline_equation", + "content": "T(\\mathbf{z}',\\mathbf{x})" + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "text", + "content": " for the generative synthesis of the latent space, producing various samples " + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{z}^{(k)}\\sim p(\\mathbf{z}|\\mathbf{z}',\\mathbf{x}) = T(\\mathbf{z}',\\mathbf{x})" + }, + { + "bbox": [ + 46, + 631, + 288, + 714 + ], + "type": "text", + "content": ". Specifically, we use an autoregressive scheme to progressively sample" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "spans": [ + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "text", + "content": "each code, i.e. " + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "inline_equation", + "content": "p(\\mathbf{z}|\\mathbf{z}',\\mathbf{x}) = \\prod_{t}p(\\mathbf{z}_{t}|\\mathbf{z}_{< t}^{(k)},\\mathbf{z}',\\mathbf{x})" + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "text", + "content": ". At the " + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "text", + "content": "-th step, the transformer takes as input the current latent code " + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_{< t}" + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "text", + "content": ", the guidance code " + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "inline_equation", + "content": "\\mathbf{z}'" + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "text", + "content": " as well as encoded sensory feature " + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "text", + "content": " as input tokens, and outputs the next token's probability over the codebook " + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "inline_equation", + "content": "p(\\mathbf{z}_t|\\mathbf{z}_{< t}^{(k)},\\mathbf{z}',\\mathbf{x})" + }, + { + "bbox": [ + 304, + 71, + 545, + 135 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 377, + 144, + 545, + 159 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 377, + 144, + 545, + 159 + ], + "spans": [ + { + "bbox": [ + 377, + 144, + 545, + 159 + ], + "type": "interline_equation", + "content": "\\mathbf {z} _ {t} ^ {(k)} \\sim p \\left(\\mathbf {z} _ {t} \\mid \\mathbf {z} _ {< t} ^ {(k)}, \\mathbf {z} ^ {\\prime}, \\mathbf {x}\\right) \\tag {2}", + "image_path": "0b64cad1a26428ab25d20cade95b7ee95fb3726c45a2308ea71cd9dfa6db56e8.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "spans": [ + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "type": "inline_equation", + "content": "p(\\mathbf{z}_t|\\mathbf{z}_{< t}^{(k)},\\mathbf{z}',\\mathbf{x})" + }, + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "type": "text", + "content": " is the conditional probability estimated from the transformer. We use nucleus sampling [25] to get multiple diverse " + }, + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "type": "inline_equation", + "content": "\\mathbf{z}^{(k)}" + }, + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "type": "text", + "content": ", which trades-off between sampling quality and diversity. Finally, these samples are decoded into multiple output samples using a decoder " + }, + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "type": "inline_equation", + "content": "G(\\cdot)" + }, + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "type": "text", + "content": ": " + }, + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "type": "inline_equation", + "content": "\\mathbf{y}^{(k)} = G(\\mathbf{z}^{(k)})" + }, + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "type": "text", + "content": ", which provides our final layout estimation samples. Formally speaking, the entire second stage can be written as follows:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 339, + 275, + 545, + 289 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 339, + 275, + 545, + 289 + ], + "spans": [ + { + "bbox": [ + 339, + 275, + 545, + 289 + ], + "type": "interline_equation", + "content": "\\mathbf {y} ^ {(k)} = G \\left(\\mathbf {z} ^ {(k)}\\right) \\text {w h e r e} \\mathbf {z} ^ {(k)} \\sim p \\left(\\mathbf {z} \\mid \\mathbf {z} ^ {\\prime}, \\mathbf {x}\\right). \\tag {3}", + "image_path": "73f2d5552387de38261de35449e917deb669e3486135e05d23bca112f1658fa5.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 314, + 545, + 374 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 314, + 545, + 374 + ], + "spans": [ + { + "bbox": [ + 304, + 314, + 545, + 374 + ], + "type": "text", + "content": "One-step generation. To enhance inference speed, we introduce a one-step variant of MapPrior, which generates a single sample rather than multiple diverse ones. It also produces tokens in a single step, bypassing the autoregressive sampling strategy:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 362, + 384, + 545, + 396 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 362, + 384, + 545, + 396 + ], + "spans": [ + { + "bbox": [ + 362, + 384, + 545, + 396 + ], + "type": "interline_equation", + "content": "\\mathbf {y} = G (\\mathbf {z}) \\text {w h e r e} \\mathbf {z} \\sim p (\\mathbf {z} | \\mathbf {x}). \\tag {4}", + "image_path": "3637d4ad1c420ede3af79469e6099637018a31172292e4cb5469545c0dbf53a0.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 406, + 547, + 430 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 406, + 547, + 430 + ], + "spans": [ + { + "bbox": [ + 304, + 406, + 547, + 430 + ], + "type": "text", + "content": "This provides an effective way to trade off between the generation quality and efficiency." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 437, + 372, + 450 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 437, + 372, + 450 + ], + "spans": [ + { + "bbox": [ + 306, + 437, + 372, + 450 + ], + "type": "text", + "content": "3.3. Learning" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "spans": [ + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "type": "text", + "content": "The training process consists of three individual components. Firstly, the perception module, denoted as " + }, + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "type": "text", + "content": ", is learned to produce a reliable initial layout estimation. Secondly, the encoder, decoder, and codebook (denoted as " + }, + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "type": "inline_equation", + "content": "E" + }, + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "type": "inline_equation", + "content": "G" + }, + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "type": "text", + "content": ", respectively) are jointly trained to represent a strong map prior model. Lastly, given a fixed map prior model, the conditional sampling transformer " + }, + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 304, + 456, + 547, + 564 + ], + "type": "text", + "content": " is learned to sample high-quality final results. In the following, we will provide a detailed description of each component's training procedure." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "spans": [ + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "type": "text", + "content": "Training the perception module. To train the perception module " + }, + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "type": "text", + "content": ", we follow the standard practice adopted in prior works [49, 56] and employ a binary cross-entropy loss. The objective function is defined as follows: " + }, + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "type": "inline_equation", + "content": "\\min_F - [\\mathbf{y}_{\\mathrm{gt}}\\log \\mathbf{y}']" + }, + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "type": "inline_equation", + "content": "\\mathbf{y}_{\\mathrm{gt}}" + }, + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "type": "text", + "content": " denotes the ground-truth label, and " + }, + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "type": "inline_equation", + "content": "\\mathbf{y}' = F(\\mathbf{x})" + }, + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "type": "text", + "content": " is the corresponding prediction given the input " + }, + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 304, + 578, + 547, + 651 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "content": "Training the map prior model. The training procedure for the map prior model involves jointly optimizing the encoder " + }, + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "inline_equation", + "content": "E" + }, + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "content": ", decoder " + }, + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "inline_equation", + "content": "G" + }, + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "content": ", and the fixed-size codebook " + }, + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "content": " in an end-to-end fashion. We use a vector-quantized auto-encoder" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 314, + 757 + ], + "type": "text", + "content": "8231" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 48, + 69, + 121, + 153 + ], + "blocks": [ + { + "bbox": [ + 48, + 69, + 121, + 153 + ], + "lines": [ + { + "bbox": [ + 48, + 69, + 121, + 153 + ], + "spans": [ + { + "bbox": [ + 48, + 69, + 121, + 153 + ], + "type": "image", + "image_path": "953c05ee9133618fc0e66d6f33e24a50dc149a602caf085862d1ca357f929e74.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 161, + 547, + 185 + ], + "lines": [ + { + "bbox": [ + 46, + 161, + 547, + 185 + ], + "spans": [ + { + "bbox": [ + 46, + 161, + 547, + 185 + ], + "type": "text", + "content": "Figure 3: MapPrior can be exploited in a progressive manner to generate perpetual traffic layouts. At each step, we choose a local area to sample to fill unexplored regions and expand the frontiers." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 126, + 68, + 214, + 152 + ], + "blocks": [ + { + "bbox": [ + 126, + 68, + 214, + 152 + ], + "lines": [ + { + "bbox": [ + 126, + 68, + 214, + 152 + ], + "spans": [ + { + "bbox": [ + 126, + 68, + 214, + 152 + ], + "type": "image", + "image_path": "cca346dd01809a0c68ebecc0918edce15d9b156e94b831f6d2894d5cec8b12c8.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 219, + 68, + 380, + 152 + ], + "blocks": [ + { + "bbox": [ + 219, + 68, + 380, + 152 + ], + "lines": [ + { + "bbox": [ + 219, + 68, + 380, + 152 + ], + "spans": [ + { + "bbox": [ + 219, + 68, + 380, + 152 + ], + "type": "image", + "image_path": "c074f79466bfcba57c21d94e5c6673eafd21f7d16ae0e1251f0236e2ed10e88a.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 385, + 70, + 545, + 152 + ], + "blocks": [ + { + "bbox": [ + 385, + 70, + 545, + 152 + ], + "lines": [ + { + "bbox": [ + 385, + 70, + 545, + 152 + ], + "spans": [ + { + "bbox": [ + 385, + 70, + 545, + 152 + ], + "type": "image", + "image_path": "0e5be95741a3e5cd1d220944ef867e075e81ea614b7a2ab1bbd4d1d8897d2b8c.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 206, + 288, + 231 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 206, + 288, + 231 + ], + "spans": [ + { + "bbox": [ + 46, + 206, + 288, + 231 + ], + "type": "text", + "content": "to reconstruct the input data " + }, + { + "bbox": [ + 46, + 206, + 288, + 231 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 46, + 206, + 288, + 231 + ], + "type": "text", + "content": " through " + }, + { + "bbox": [ + 46, + 206, + 288, + 231 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{y}} = G(\\mathbf{z}(\\mathbf{y}_i))" + }, + { + "bbox": [ + 46, + 206, + 288, + 231 + ], + "type": "text", + "content": " following Eq. 1. The following losses are minimized:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 78, + 238, + 288, + 255 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 78, + 238, + 288, + 255 + ], + "spans": [ + { + "bbox": [ + 78, + 238, + 288, + 255 + ], + "type": "interline_equation", + "content": "\\min _ {E, G, \\mathcal {C}} \\max _ {D} \\mathcal {L} _ {\\text {r e c o n}} + \\lambda_ {\\text {G A N}} \\mathcal {L} _ {\\text {G A N}} + \\mathcal {L} _ {\\text {l a t e n t}}. \\tag {5}", + "image_path": "f3d81f841d4725e3a0b32f679a6d48864244d46cd997f6bed4c4ffe6cba02905.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 262, + 287, + 297 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 262, + 287, + 297 + ], + "spans": [ + { + "bbox": [ + 47, + 262, + 287, + 297 + ], + "type": "text", + "content": "The first term, " + }, + { + "bbox": [ + 47, + 262, + 287, + 297 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{recon}}" + }, + { + "bbox": [ + 47, + 262, + 287, + 297 + ], + "type": "text", + "content": ", is the reconstruction loss, which is designed to maximize the agreement between the input " + }, + { + "bbox": [ + 47, + 262, + 287, + 297 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 47, + 262, + 287, + 297 + ], + "type": "text", + "content": " and the reconstructed output:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 124, + 303, + 288, + 317 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 124, + 303, + 288, + 317 + ], + "spans": [ + { + "bbox": [ + 124, + 303, + 288, + 317 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {r e c o n}} = \\left\\| \\hat {\\mathbf {y}} - \\mathbf {y} \\right\\| ^ {2}. \\tag {6}", + "image_path": "3b7e0e6ef7e0a7cfca6579ba00743dcef09641487a604ce7d7e0c3e0d276925b.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 323, + 288, + 418 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 323, + 288, + 418 + ], + "spans": [ + { + "bbox": [ + 46, + 323, + 288, + 418 + ], + "type": "text", + "content": "In addition to the reconstruction loss, the second term is a GAN loss inspired by VQGAN [18] to encourage the reconstructed output to be realistic with a clear local structure and topology. A local discriminator " + }, + { + "bbox": [ + 46, + 323, + 288, + 418 + ], + "type": "inline_equation", + "content": "D(\\cdot)" + }, + { + "bbox": [ + 46, + 323, + 288, + 418 + ], + "type": "text", + "content": " is trained to differentiate between real and reconstructed BEV layout using cross-entropy loss, and the " + }, + { + "bbox": [ + 46, + 323, + 288, + 418 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{GAN}}" + }, + { + "bbox": [ + 46, + 323, + 288, + 418 + ], + "type": "text", + "content": " loss aims to make the reconstructed image as realistic as possible through fooling the discriminator:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 89, + 426, + 287, + 440 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 89, + 426, + 287, + 440 + ], + "spans": [ + { + "bbox": [ + 89, + 426, + 287, + 440 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {G A N}} = \\log D (\\mathbf {y}) + \\log (1 - D (\\hat {\\mathbf {y}})), \\tag {7}", + "image_path": "12a9e6405a1e61004f77bfe9a562513b209f14fa7764f6efa4ef048a9a752ce9.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 445, + 287, + 470 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 445, + 287, + 470 + ], + "spans": [ + { + "bbox": [ + 46, + 445, + 287, + 470 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 445, + 287, + 470 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 46, + 445, + 287, + 470 + ], + "type": "text", + "content": " is a real sample and " + }, + { + "bbox": [ + 46, + 445, + 287, + 470 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{y}}" + }, + { + "bbox": [ + 46, + 445, + 287, + 470 + ], + "type": "text", + "content": " is a reconstructed sample. Following VQGAN [18], this loss is rescaled by" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 113, + 476, + 287, + 491 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 113, + 476, + 287, + 491 + ], + "spans": [ + { + "bbox": [ + 113, + 476, + 287, + 491 + ], + "type": "interline_equation", + "content": "\\lambda_ {\\mathrm {G A N}} = g _ {\\mathrm {r e c}} / \\left(g _ {\\mathrm {G A N}} + \\sigma\\right), \\tag {8}", + "image_path": "78e3a64a36ba59f9e5f500a0952a54e56c4d0380cc5f28f0275e407f04ec8a21.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 496, + 287, + 519 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 496, + 287, + 519 + ], + "spans": [ + { + "bbox": [ + 46, + 496, + 287, + 519 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 496, + 287, + 519 + ], + "type": "inline_equation", + "content": "g_{\\mathrm{rec}}" + }, + { + "bbox": [ + 46, + 496, + 287, + 519 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 496, + 287, + 519 + ], + "type": "inline_equation", + "content": "g_{\\mathrm{GAN}}" + }, + { + "bbox": [ + 46, + 496, + 287, + 519 + ], + "type": "text", + "content": " are gradients of " + }, + { + "bbox": [ + 46, + 496, + 287, + 519 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{rec}}" + }, + { + "bbox": [ + 46, + 496, + 287, + 519 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 496, + 287, + 519 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{GAN}}" + }, + { + "bbox": [ + 46, + 496, + 287, + 519 + ], + "type": "text", + "content": " with respect to the last layer of the generator." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 520, + 287, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 520, + 287, + 567 + ], + "spans": [ + { + "bbox": [ + 46, + 520, + 287, + 567 + ], + "type": "text", + "content": "The last term promotes the expressiveness of the codebook. We expect the latent feature " + }, + { + "bbox": [ + 46, + 520, + 287, + 567 + ], + "type": "inline_equation", + "content": "E(\\mathbf{y})" + }, + { + "bbox": [ + 46, + 520, + 287, + 567 + ], + "type": "text", + "content": " to be close to its nearest codebook token and vice versa. Thus, the latent loss is defined as" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 69, + 574, + 287, + 588 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 574, + 287, + 588 + ], + "spans": [ + { + "bbox": [ + 69, + 574, + 287, + 588 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {l a t e n t}} = \\left\\| \\mathbf {z} - \\operatorname {s g} [ E (\\mathbf {y}) ] \\right\\| ^ {2} + \\left\\| \\operatorname {s g} [ \\mathbf {z} ] - E (\\mathbf {y}) \\right\\| ^ {2}, \\tag {9}", + "image_path": "6b7b888a15ac8dbbf077eace150a23702f4d591ea78ccd034cbc271c8852e062.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 47, + 594, + 212, + 607 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 594, + 212, + 607 + ], + "spans": [ + { + "bbox": [ + 47, + 594, + 212, + 607 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 594, + 212, + 607 + ], + "type": "inline_equation", + "content": "\\mathrm{sg}[\\cdot ]" + }, + { + "bbox": [ + 47, + 594, + 212, + 607 + ], + "type": "text", + "content": " is a gradient detach operator." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 46, + 620, + 288, + 692 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 620, + 288, + 692 + ], + "spans": [ + { + "bbox": [ + 46, + 620, + 288, + 692 + ], + "type": "text", + "content": "Training the conditional sampler. Our conditional sampling transformer, denoted as " + }, + { + "bbox": [ + 46, + 620, + 288, + 692 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 46, + 620, + 288, + 692 + ], + "type": "text", + "content": ", is trained in the latent code space to sample high-likelihood latent codes given input controlling guidance. Given a paired input and output " + }, + { + "bbox": [ + 46, + 620, + 288, + 692 + ], + "type": "inline_equation", + "content": "(\\mathbf{x},\\mathbf{y})" + }, + { + "bbox": [ + 46, + 620, + 288, + 692 + ], + "type": "text", + "content": " and fixed perception module " + }, + { + "bbox": [ + 46, + 620, + 288, + 692 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 46, + 620, + 288, + 692 + ], + "type": "text", + "content": ", map prior model " + }, + { + "bbox": [ + 46, + 620, + 288, + 692 + ], + "type": "inline_equation", + "content": "E,G,C" + }, + { + "bbox": [ + 46, + 620, + 288, + 692 + ], + "type": "text", + "content": ", the transformer is trained using the following objective:" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 129, + 699, + 287, + 716 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 129, + 699, + 287, + 716 + ], + "spans": [ + { + "bbox": [ + 129, + 699, + 287, + 716 + ], + "type": "interline_equation", + "content": "\\min _ {T} \\mathcal {L} _ {\\mathrm {C E}} + \\mathcal {L} _ {\\text {o u t}}. \\tag {10}", + "image_path": "f03f72075373831fcb34c06a7dd8583551e6ab13031eba368a5d3ecd7544e892.jpg" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 305, + 206, + 547, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 206, + 547, + 266 + ], + "spans": [ + { + "bbox": [ + 305, + 206, + 547, + 266 + ], + "type": "text", + "content": "The first loss, " + }, + { + "bbox": [ + 305, + 206, + 547, + 266 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{CE}}" + }, + { + "bbox": [ + 305, + 206, + 547, + 266 + ], + "type": "text", + "content": ", optimizes the transformer to maximize the estimated probability of the latent code of the ground-truth layout. We use a cross-entropy loss between the transformer's estimated probability " + }, + { + "bbox": [ + 305, + 206, + 547, + 266 + ], + "type": "inline_equation", + "content": "T(\\mathbf{z}',\\mathbf{x})" + }, + { + "bbox": [ + 305, + 206, + 547, + 266 + ], + "type": "text", + "content": " and the ground-truth sample " + }, + { + "bbox": [ + 305, + 206, + 547, + 266 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 305, + 206, + 547, + 266 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 354, + 275, + 546, + 300 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 354, + 275, + 546, + 300 + ], + "spans": [ + { + "bbox": [ + 354, + 275, + 546, + 300 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {C E}} = \\sum_ {t} \\sum_ {i} \\mathbf {y} _ {i, t} \\log T _ {i, t} \\left(\\mathbf {z} ^ {\\prime}, \\mathbf {x}\\right), \\tag {11}", + "image_path": "ecdc5f15183688921d3dbb7e27f6267825945ddb78b2fa86eb0b0c27f501b815.jpg" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 305, + 308, + 545, + 331 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 308, + 545, + 331 + ], + "spans": [ + { + "bbox": [ + 305, + 308, + 545, + 331 + ], + "type": "text", + "content": "where, " + }, + { + "bbox": [ + 305, + 308, + 545, + 331 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 305, + 308, + 545, + 331 + ], + "type": "text", + "content": " represents the " + }, + { + "bbox": [ + 305, + 308, + 545, + 331 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 305, + 308, + 545, + 331 + ], + "type": "text", + "content": "-th output label, and " + }, + { + "bbox": [ + 305, + 308, + 545, + 331 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 305, + 308, + 545, + 331 + ], + "type": "text", + "content": " represents the " + }, + { + "bbox": [ + 305, + 308, + 545, + 331 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 305, + 308, + 545, + 331 + ], + "type": "text", + "content": "-th autoregressive step." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 331, + 546, + 414 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 331, + 546, + 414 + ], + "spans": [ + { + "bbox": [ + 304, + 331, + 546, + 414 + ], + "type": "text", + "content": "Although making the latent code closer to the ground-truth map's latent code is essential, it is not sufficient to ensure high output fidelity. Hence, we include an additional reconstruction output loss that encourages the transformer to favor samples that produce high-accuracy layouts. Similar to the reconstruction loss in auto-encoding training, an L2 reconstruction loss is used:" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 387, + 423, + 546, + 437 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 387, + 423, + 546, + 437 + ], + "spans": [ + { + "bbox": [ + 387, + 423, + 546, + 437 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {o u t}} = \\left\\| \\mathbf {y} - \\hat {\\mathbf {y}} \\right\\| _ {2} ^ {2}, \\tag {12}", + "image_path": "a2cba53d816ba3665d4d68bcc96a847d9294e6969f4a287d38e7a0db8b7030b5.jpg" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 304, + 446, + 547, + 494 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 446, + 547, + 494 + ], + "spans": [ + { + "bbox": [ + 304, + 446, + 547, + 494 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 446, + 547, + 494 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 304, + 446, + 547, + 494 + ], + "type": "text", + "content": " is the true map and " + }, + { + "bbox": [ + 304, + 446, + 547, + 494 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{y}}" + }, + { + "bbox": [ + 304, + 446, + 547, + 494 + ], + "type": "text", + "content": " is the predicted map. Note that codebook selection in latent code space is non-differentiable; thus, we use Gumbel-Softmax [29] to ensure differentiability in practice throughout the training processes." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 306, + 501, + 382, + 512 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 501, + 382, + 512 + ], + "spans": [ + { + "bbox": [ + 306, + 501, + 382, + 512 + ], + "type": "text", + "content": "3.4. Discussions" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 304, + 519, + 547, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 519, + 547, + 590 + ], + "spans": [ + { + "bbox": [ + 304, + 519, + 547, + 590 + ], + "type": "text", + "content": "Uncertainty quantification. Our latent transformer offers diverse results " + }, + { + "bbox": [ + 304, + 519, + 547, + 590 + ], + "type": "inline_equation", + "content": "\\mathbf{y}^{(k)}" + }, + { + "bbox": [ + 304, + 519, + 547, + 590 + ], + "type": "text", + "content": " by using a conditional sampling scheme. By estimating the variance of " + }, + { + "bbox": [ + 304, + 519, + 547, + 590 + ], + "type": "inline_equation", + "content": "\\mathbf{y}^{(k)}" + }, + { + "bbox": [ + 304, + 519, + 547, + 590 + ], + "type": "text", + "content": ", we can estimate the uncertainty map for our results. By using the average of " + }, + { + "bbox": [ + 304, + 519, + 547, + 590 + ], + "type": "inline_equation", + "content": "\\mathbf{y}^{(k)}" + }, + { + "bbox": [ + 304, + 519, + 547, + 590 + ], + "type": "text", + "content": ", we aggregate the diverse result samples to a more stable and better calibrated results." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 304, + 605, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 547, + 714 + ], + "type": "text", + "content": "Perpetual layout generation. Our trained map prior enables the continuous generation of realistic and varied driving sequences, which are extremely valuable for content creation and autonomous driving simulations. We use a progressive generation strategy, which builds upon prior works [3, 17, 45, 65, 18, 9]. The strategy involves iteratively expanding our visual horizon and generating new content by leveraging our map prior model to fill in the previously unseen areas. We illustrate this process in Fig. 3." + } + ] + } + ], + "index": 27 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "8232" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 49, + 103, + 545, + 308 + ], + "blocks": [ + { + "bbox": [ + 47, + 70, + 547, + 95 + ], + "lines": [ + { + "bbox": [ + 47, + 70, + 547, + 95 + ], + "spans": [ + { + "bbox": [ + 47, + 70, + 547, + 95 + ], + "type": "text", + "content": "Table 1: Quantitative results of BEV map segmentation on nuScenes. Our MapPrior achieves better accuracy (IoU), realism (MMD) and uncertainty awareness (ECE) than discriminative BEV perception baselines." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 49, + 103, + 545, + 308 + ], + "lines": [ + { + "bbox": [ + 49, + 103, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 49, + 103, + 545, + 308 + ], + "type": "table", + "html": "
ModalityIoU (↑)MMD (↓)ECE (↓)
DrivablePed. XWalkwayStop LineCarparkDividerMean
OFT [60]C74.035.345.927.535.933.942.154.50.045
LSS [56]C75.438.846.330.339.136.544.443.20.041
BEVFusion-C [49]C81.754.858.447.450.746.456.639.60.038
MapPrior-CC81.754.658.346.753.345.156.728.40.026
MapPrior-C (1 step)C81.654.658.446.853.945.156.728.7-
PointPillars [38]L72.043.153.129.727.737.543.8153.00.111
BEVFusion-L [80, 49]L75.648.457.536.531.741.948.6115.20.090
MapPrior-LL81.049.758.037.538.242.451.135.80.038
MapPrior-L (1 step)L80.149.057.837.833.042.550.050.2-
PointPainting [75]C+L75.948.557.136.924.541.949.1109.80.099
MVP [81]C+L76.148.757.036.933.042.249.0115.30.096
BEVFusion [49]C+L85.560.567.652.057.053.762.721.60.038
MapPrior-CLC+L85.361.467.151.760.053.363.128.00.020
MapPrior-CL (1 step)C+L85.361.367.051.759.653.163.028.1-
", + "image_path": "6cbba0f7ff5284bda1741d56e27055e23055c2780b2abc46218a98071460892c.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 337, + 128, + 351 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 337, + 128, + 351 + ], + "spans": [ + { + "bbox": [ + 47, + 337, + 128, + 351 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 357, + 290, + 490 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 357, + 290, + 490 + ], + "spans": [ + { + "bbox": [ + 46, + 357, + 290, + 490 + ], + "type": "text", + "content": "We evaluate our MapPrior on BEV map segmentation and generation tasks for both LiDAR and camera modalities. We evaluate our approach to generate an accurate and realistic traffic layout both quantitatively and qualitatively in Sec. 4.2. We show how output loss and BEV features can affect our performance in Tab. 2. We finally estimate how our model can generate diverse samples and how our model is calibrated using the diverse samples in Fig. 5 and 6. Specifically, we are interested in seeing how using a generative prior affects accuracy (reflected by mIoU), realism (reflected by MMD), and model calibration (reflected by ECE)." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 498, + 164, + 511 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 498, + 164, + 511 + ], + "spans": [ + { + "bbox": [ + 47, + 498, + 164, + 511 + ], + "type": "text", + "content": "4.1. Experimental Setup" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 517, + 288, + 673 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 517, + 288, + 673 + ], + "spans": [ + { + "bbox": [ + 46, + 517, + 288, + 673 + ], + "type": "text", + "content": "Datasets. We evaluate our model on nuScenes [6], a large-scale outdoor autonomous driving dataset containing 1000 driving scenes, consisting of 700 scenes for training, 150 for validation, and 150 scenes for testing. It has around 40,000 annotated key-frames, each with six monocular camera images encompassing a 360-degree FoV (used by camera models), and a 32-beam LiDAR scan (used by LiDAR models). We follow the train/validation split provided by nuScenes. We evaluate all models on the validation set following common practices in BEV layout estimation [49, 56]. The ground truth segmentation map is provided by nuScenes and was labeled manually [6]. We rasterized the map layers from the nuScenes map into the ego frame." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 689, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 689, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 689, + 289, + 715 + ], + "type": "text", + "content": "Metrics. We provide quantitative results for both segmentation and generative tasks. For BEV map segmentation," + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 338, + 547, + 445 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 338, + 547, + 445 + ], + "spans": [ + { + "bbox": [ + 304, + 338, + 547, + 445 + ], + "type": "text", + "content": "our metric is the Intersection-over-Union (IoU score) for six map classes (drivable area, pedestrian crossing, walkway, stop line, car-parking area, and lane divider), as well as the mean IoU averaged over all six map classes. Since different classes may overlap, we separately compare the IoU score for each class. For all baseline predictive models, we choose the best threshold that maximizes IoU for comparison to ensure no bias is introduced due to the suboptimal threshold selection. For MapPrior, we simply use 0.5 as the threshold." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 446, + 547, + 506 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 446, + 547, + 506 + ], + "spans": [ + { + "bbox": [ + 304, + 446, + 547, + 506 + ], + "type": "text", + "content": "To evaluate generated map layout realism, we use the maximum mean discrepancy (MMD) metric. MMD effectively measures the distance between two distributions of two sets of samples by measuring the squared difference of their mean in different spaces:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 309, + 513, + 545, + 590 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 513, + 545, + 590 + ], + "spans": [ + { + "bbox": [ + 309, + 513, + 545, + 590 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathrm {M M D} = \\sum_ {i} ^ {n} \\sum_ {i ^ {\\prime}} ^ {n} k (\\mathbf {x} _ {i}, \\mathbf {x} _ {i ^ {\\prime}}) / n ^ {2} + \\sum_ {j} ^ {m} \\sum_ {j ^ {\\prime}} ^ {m} k (\\mathbf {x} _ {j}, \\mathbf {x} _ {j ^ {\\prime}}) / m ^ {2} \\\\ - 2 \\cdot \\sum_ {i} ^ {n} \\sum_ {j} ^ {m} k \\left(\\mathbf {x} _ {i}, \\mathbf {x} _ {j}\\right) / n m. \\tag {13} \\\\ \\end{array}", + "image_path": "2a85914eea0ab708c9497ed0f27b30ceac3c651a97efd12fe415f74425299cba.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 591, + 545, + 614 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 591, + 545, + 614 + ], + "spans": [ + { + "bbox": [ + 304, + 591, + 545, + 614 + ], + "type": "text", + "content": "To evaluate a set of predicted layouts, we compare it with a set of ground truth layouts from nuScenes." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 615, + 547, + 675 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 615, + 547, + 675 + ], + "spans": [ + { + "bbox": [ + 304, + 615, + 547, + 675 + ], + "type": "text", + "content": "To evaluate uncertainty in our diversity results, we use Expected Calibration Error (ECE) [36, 22]. ECE compares output probabilities to model accuracy. It splits the results into several bins and measures a weighted average discrepancy between accuracy and confidence within each bin:" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 349, + 682, + 547, + 715 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 349, + 682, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 349, + 682, + 547, + 715 + ], + "type": "interline_equation", + "content": "\\mathrm {E C E} = \\sum_ {b} ^ {B} n _ {b} | \\operatorname {a c c} (b) - \\operatorname {c o n f} (b) | / n, \\tag {14}", + "image_path": "f7d4a3ad8f7d5efeefeb903680ab047088f6036fb15f64f6f4dfbab3a78b3921.jpg" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "8233" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 56, + 69, + 121, + 197 + ], + "blocks": [ + { + "bbox": [ + 56, + 69, + 121, + 197 + ], + "lines": [ + { + "bbox": [ + 56, + 69, + 121, + 197 + ], + "spans": [ + { + "bbox": [ + 56, + 69, + 121, + 197 + ], + "type": "image", + "image_path": "8c0a7cd2ec75e19801d69437c071be755b8dba191b69914ad980e8322936f809.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 77, + 199, + 100, + 207 + ], + "lines": [ + { + "bbox": [ + 77, + 199, + 100, + 207 + ], + "spans": [ + { + "bbox": [ + 77, + 199, + 100, + 207 + ], + "type": "text", + "content": "LiDAR" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 130, + 70, + 227, + 197 + ], + "blocks": [ + { + "bbox": [ + 130, + 70, + 227, + 197 + ], + "lines": [ + { + "bbox": [ + 130, + 70, + 227, + 197 + ], + "spans": [ + { + "bbox": [ + 130, + 70, + 227, + 197 + ], + "type": "image", + "image_path": "c6056e214c5e7ad83f84a11833a522ce91be20bd4309524ee214f31e0d2237b6.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 158, + 199, + 199, + 207 + ], + "lines": [ + { + "bbox": [ + 158, + 199, + 199, + 207 + ], + "spans": [ + { + "bbox": [ + 158, + 199, + 199, + 207 + ], + "type": "text", + "content": "PointPillars" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 236, + 70, + 332, + 198 + ], + "blocks": [ + { + "bbox": [ + 236, + 70, + 332, + 198 + ], + "lines": [ + { + "bbox": [ + 236, + 70, + 332, + 198 + ], + "spans": [ + { + "bbox": [ + 236, + 70, + 332, + 198 + ], + "type": "image", + "image_path": "91e9b2d302669c58fc7b2a539837ba5fd40a41af99df56172a922038615ffe52.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 261, + 199, + 307, + 207 + ], + "lines": [ + { + "bbox": [ + 261, + 199, + 307, + 207 + ], + "spans": [ + { + "bbox": [ + 261, + 199, + 307, + 207 + ], + "type": "text", + "content": "BEVFusion-L" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 342, + 70, + 437, + 198 + ], + "blocks": [ + { + "bbox": [ + 342, + 70, + 437, + 198 + ], + "lines": [ + { + "bbox": [ + 342, + 70, + 437, + 198 + ], + "spans": [ + { + "bbox": [ + 342, + 70, + 437, + 198 + ], + "type": "image", + "image_path": "59a64753780a79c0d7b7d9e81693a0c999777c379f5f8125a530f956e3aba46a.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 359, + 199, + 420, + 209 + ], + "lines": [ + { + "bbox": [ + 359, + 199, + 420, + 209 + ], + "spans": [ + { + "bbox": [ + 359, + 199, + 420, + 209 + ], + "type": "text", + "content": "MapPrior-L (Ours)" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 449, + 70, + 542, + 198 + ], + "blocks": [ + { + "bbox": [ + 449, + 70, + 542, + 198 + ], + "lines": [ + { + "bbox": [ + 449, + 70, + 542, + 198 + ], + "spans": [ + { + "bbox": [ + 449, + 70, + 542, + 198 + ], + "type": "image", + "image_path": "821ca6780cdf4b03e11c80221f178af8630bc5c138ca0fc20418c995106d8855.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 471, + 199, + 518, + 208 + ], + "lines": [ + { + "bbox": [ + 471, + 199, + 518, + 208 + ], + "spans": [ + { + "bbox": [ + 471, + 199, + 518, + 208 + ], + "type": "text", + "content": "Ground Truth" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 56, + 226, + 121, + 269 + ], + "blocks": [ + { + "bbox": [ + 56, + 226, + 121, + 269 + ], + "lines": [ + { + "bbox": [ + 56, + 226, + 121, + 269 + ], + "spans": [ + { + "bbox": [ + 56, + 226, + 121, + 269 + ], + "type": "image", + "image_path": "3b004600bd4c1323365e21a3afa15a06d6a61252d7a09e58d8e80ac180ac310e.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 74, + 279, + 102, + 288 + ], + "lines": [ + { + "bbox": [ + 74, + 279, + 102, + 288 + ], + "spans": [ + { + "bbox": [ + 74, + 279, + 102, + 288 + ], + "type": "text", + "content": "Camera" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 132, + 213, + 227, + 277 + ], + "blocks": [ + { + "bbox": [ + 132, + 213, + 227, + 277 + ], + "lines": [ + { + "bbox": [ + 132, + 213, + 227, + 277 + ], + "spans": [ + { + "bbox": [ + 132, + 213, + 227, + 277 + ], + "type": "image", + "image_path": "d4f3cb944cbccd6bec267d3c2352aaf29f95d9c19f45aecaaf682c914b0025a7.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 170, + 279, + 186, + 287 + ], + "lines": [ + { + "bbox": [ + 170, + 279, + 186, + 287 + ], + "spans": [ + { + "bbox": [ + 170, + 279, + 186, + 287 + ], + "type": "text", + "content": "LSS" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 236, + 214, + 332, + 277 + ], + "blocks": [ + { + "bbox": [ + 236, + 214, + 332, + 277 + ], + "lines": [ + { + "bbox": [ + 236, + 214, + 332, + 277 + ], + "spans": [ + { + "bbox": [ + 236, + 214, + 332, + 277 + ], + "type": "image", + "image_path": "7d5c983dc468668b9c00dfeca3308d9d1abf3d45bda8c6afad51e49a9caf4198.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 260, + 279, + 307, + 288 + ], + "lines": [ + { + "bbox": [ + 260, + 279, + 307, + 288 + ], + "spans": [ + { + "bbox": [ + 260, + 279, + 307, + 288 + ], + "type": "text", + "content": "BEVFusion-C" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 342, + 214, + 437, + 277 + ], + "blocks": [ + { + "bbox": [ + 342, + 214, + 437, + 277 + ], + "lines": [ + { + "bbox": [ + 342, + 214, + 437, + 277 + ], + "spans": [ + { + "bbox": [ + 342, + 214, + 437, + 277 + ], + "type": "image", + "image_path": "03c37265a3456af4e3481128b0c1bf03f54f4e6935a7c62f5178e76355360829.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 358, + 279, + 421, + 289 + ], + "lines": [ + { + "bbox": [ + 358, + 279, + 421, + 289 + ], + "spans": [ + { + "bbox": [ + 358, + 279, + 421, + 289 + ], + "type": "text", + "content": "MapPrior-C (Ours)" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_caption" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 449, + 214, + 543, + 277 + ], + "blocks": [ + { + "bbox": [ + 449, + 214, + 543, + 277 + ], + "lines": [ + { + "bbox": [ + 449, + 214, + 543, + 277 + ], + "spans": [ + { + "bbox": [ + 449, + 214, + 543, + 277 + ], + "type": "image", + "image_path": "c1619230200892b0940f88f483493b5dd77e80f150431ee1ed19cd075f44d580.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 471, + 279, + 518, + 288 + ], + "lines": [ + { + "bbox": [ + 471, + 279, + 518, + 288 + ], + "spans": [ + { + "bbox": [ + 471, + 279, + 518, + 288 + ], + "type": "text", + "content": "Ground Truth" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 56, + 296, + 119, + 357 + ], + "blocks": [ + { + "bbox": [ + 56, + 296, + 119, + 357 + ], + "lines": [ + { + "bbox": [ + 56, + 296, + 119, + 357 + ], + "spans": [ + { + "bbox": [ + 56, + 296, + 119, + 357 + ], + "type": "image", + "image_path": "c105640b6fbfec181b3a8bad34335c909a84df41f252be75113bf336096f4633.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 75, + 362, + 99, + 371 + ], + "lines": [ + { + "bbox": [ + 75, + 362, + 99, + 371 + ], + "spans": [ + { + "bbox": [ + 75, + 362, + 99, + 371 + ], + "type": "text", + "content": "LiDAR" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_caption" + } + ], + "index": 20 + }, + { + "type": "image", + "bbox": [ + 136, + 303, + 212, + 350 + ], + "blocks": [ + { + "bbox": [ + 136, + 303, + 212, + 350 + ], + "lines": [ + { + "bbox": [ + 136, + 303, + 212, + 350 + ], + "spans": [ + { + "bbox": [ + 136, + 303, + 212, + 350 + ], + "type": "image", + "image_path": "d86c05ac6253002579e4dfbf6d49c953b0d943a0cc897e4464eac1002b6ba57c.jpg" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 159, + 363, + 187, + 372 + ], + "lines": [ + { + "bbox": [ + 159, + 363, + 187, + 372 + ], + "spans": [ + { + "bbox": [ + 159, + 363, + 187, + 372 + ], + "type": "text", + "content": "Camera" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_caption" + } + ], + "index": 22 + }, + { + "type": "image", + "bbox": [ + 238, + 293, + 332, + 356 + ], + "blocks": [ + { + "bbox": [ + 238, + 293, + 332, + 356 + ], + "lines": [ + { + "bbox": [ + 238, + 293, + 332, + 356 + ], + "spans": [ + { + "bbox": [ + 238, + 293, + 332, + 356 + ], + "type": "image", + "image_path": "7a7434b0aadebd182e7ec8587e88bd28cef3fb2a8640ce61279bbc34f43d8115.jpg" + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 260, + 361, + 313, + 369 + ], + "lines": [ + { + "bbox": [ + 260, + 361, + 313, + 369 + ], + "spans": [ + { + "bbox": [ + 260, + 361, + 313, + 369 + ], + "type": "text", + "content": "BEVFusion-CL" + } + ] + } + ], + "index": 25, + "angle": 0, + "type": "image_caption" + } + ], + "index": 24 + }, + { + "type": "image", + "bbox": [ + 345, + 293, + 439, + 356 + ], + "blocks": [ + { + "bbox": [ + 345, + 293, + 439, + 356 + ], + "lines": [ + { + "bbox": [ + 345, + 293, + 439, + 356 + ], + "spans": [ + { + "bbox": [ + 345, + 293, + 439, + 356 + ], + "type": "image", + "image_path": "5a2968f5a77acc40447164e0f8b6da72c064db29f42f328f1c152df7797271c4.jpg" + } + ] + } + ], + "index": 26, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 359, + 361, + 425, + 370 + ], + "lines": [ + { + "bbox": [ + 359, + 361, + 425, + 370 + ], + "spans": [ + { + "bbox": [ + 359, + 361, + 425, + 370 + ], + "type": "text", + "content": "MapPrior-CL (Ours)" + } + ] + } + ], + "index": 27, + "angle": 0, + "type": "image_caption" + } + ], + "index": 26 + }, + { + "type": "image", + "bbox": [ + 452, + 293, + 546, + 356 + ], + "blocks": [ + { + "bbox": [ + 452, + 293, + 546, + 356 + ], + "lines": [ + { + "bbox": [ + 452, + 293, + 546, + 356 + ], + "spans": [ + { + "bbox": [ + 452, + 293, + 546, + 356 + ], + "type": "image", + "image_path": "ad1364e78541555d8ca3946ecdb59ce51a9525c567e783f93e0d822aabbb166c.jpg" + } + ] + } + ], + "index": 28, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 473, + 361, + 520, + 370 + ], + "lines": [ + { + "bbox": [ + 473, + 361, + 520, + 370 + ], + "spans": [ + { + "bbox": [ + 473, + 361, + 520, + 370 + ], + "type": "text", + "content": "Ground Truth" + } + ] + } + ], + "index": 29, + "angle": 0, + "type": "image_caption" + } + ], + "index": 28 + }, + { + "type": "image", + "bbox": [ + 53, + 434, + 129, + 510 + ], + "blocks": [ + { + "bbox": [ + 46, + 388, + 546, + 424 + ], + "lines": [ + { + "bbox": [ + 46, + 388, + 546, + 424 + ], + "spans": [ + { + "bbox": [ + 46, + 388, + 546, + 424 + ], + "type": "text", + "content": "Figure 4: Qualitative results of BEV map segmentation on nuScenes. Discriminative BEV perception baselines produce results with clear artifacts (e.g., lane markings are discontinuous, roads and pedestrian walkways have unrealistic gaps, etc.). In contrast, our MapPrior produces semantic map layouts that are clean, realistic, and in-distribution." + } + ] + } + ], + "index": 30, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 53, + 434, + 129, + 510 + ], + "lines": [ + { + "bbox": [ + 53, + 434, + 129, + 510 + ], + "spans": [ + { + "bbox": [ + 53, + 434, + 129, + 510 + ], + "type": "image", + "image_path": "6a89fa43641c322d2b06e5ec347db4dea8b7add94db677290eae51de8bd95f96.jpg" + } + ] + } + ], + "index": 31, + "angle": 0, + "type": "image_body" + } + ], + "index": 31 + }, + { + "type": "image", + "bbox": [ + 53, + 511, + 129, + 585 + ], + "blocks": [ + { + "bbox": [ + 53, + 511, + 129, + 585 + ], + "lines": [ + { + "bbox": [ + 53, + 511, + 129, + 585 + ], + "spans": [ + { + "bbox": [ + 53, + 511, + 129, + 585 + ], + "type": "image", + "image_path": "04f60e24881c3e2c2fcf8aeaace46a1ad8b9dd74188d036439cbf2dbce2cf6f3.jpg" + } + ] + } + ], + "index": 32, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 80, + 587, + 102, + 598 + ], + "lines": [ + { + "bbox": [ + 80, + 587, + 102, + 598 + ], + "spans": [ + { + "bbox": [ + 80, + 587, + 102, + 598 + ], + "type": "text", + "content": "Input" + } + ] + } + ], + "index": 33, + "angle": 0, + "type": "image_caption" + } + ], + "index": 32 + }, + { + "type": "image", + "bbox": [ + 137, + 452, + 213, + 498 + ], + "blocks": [ + { + "bbox": [ + 137, + 452, + 213, + 498 + ], + "lines": [ + { + "bbox": [ + 137, + 452, + 213, + 498 + ], + "spans": [ + { + "bbox": [ + 137, + 452, + 213, + 498 + ], + "type": "image", + "image_path": "e5e48dccf8aca33770969d1ea6f6fae01a0231033930f7a2ed982897cd680ef1.jpg" + } + ] + } + ], + "index": 34, + "angle": 0, + "type": "image_body" + } + ], + "index": 34 + }, + { + "type": "image", + "bbox": [ + 137, + 509, + 214, + 586 + ], + "blocks": [ + { + "bbox": [ + 137, + 509, + 214, + 586 + ], + "lines": [ + { + "bbox": [ + 137, + 509, + 214, + 586 + ], + "spans": [ + { + "bbox": [ + 137, + 509, + 214, + 586 + ], + "type": "image", + "image_path": "0544d9923024765b5bbe5c09d25563d7a95a7e70e8b2742f7abd7e304205e927.jpg" + } + ] + } + ], + "index": 35, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 167, + 587, + 182, + 597 + ], + "lines": [ + { + "bbox": [ + 167, + 587, + 182, + 597 + ], + "spans": [ + { + "bbox": [ + 167, + 587, + 182, + 597 + ], + "type": "text", + "content": "GT" + } + ] + } + ], + "index": 36, + "angle": 0, + "type": "image_caption" + } + ], + "index": 35 + }, + { + "type": "image", + "bbox": [ + 220, + 452, + 296, + 498 + ], + "blocks": [ + { + "bbox": [ + 220, + 452, + 296, + 498 + ], + "lines": [ + { + "bbox": [ + 220, + 452, + 296, + 498 + ], + "spans": [ + { + "bbox": [ + 220, + 452, + 296, + 498 + ], + "type": "image", + "image_path": "e72a1a1e7221652d0c2f5a07befa49eed0c07fb61420f9911088fb271af0de4c.jpg" + } + ] + } + ], + "index": 37, + "angle": 0, + "type": "image_body" + } + ], + "index": 37 + }, + { + "type": "image", + "bbox": [ + 220, + 510, + 297, + 585 + ], + "blocks": [ + { + "bbox": [ + 220, + 510, + 297, + 585 + ], + "lines": [ + { + "bbox": [ + 220, + 510, + 297, + 585 + ], + "spans": [ + { + "bbox": [ + 220, + 510, + 297, + 585 + ], + "type": "image", + "image_path": "c8c4c631599a0ea43c374d792df7fe1bacff4faa433e871ca382a49974a218a4.jpg" + } + ] + } + ], + "index": 38, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 230, + 587, + 286, + 598 + ], + "lines": [ + { + "bbox": [ + 230, + 587, + 286, + 598 + ], + "spans": [ + { + "bbox": [ + 230, + 587, + 286, + 598 + ], + "type": "text", + "content": "Our Sample 1" + } + ] + } + ], + "index": 39, + "angle": 0, + "type": "image_caption" + } + ], + "index": 38 + }, + { + "type": "image", + "bbox": [ + 304, + 451, + 380, + 498 + ], + "blocks": [ + { + "bbox": [ + 304, + 451, + 380, + 498 + ], + "lines": [ + { + "bbox": [ + 304, + 451, + 380, + 498 + ], + "spans": [ + { + "bbox": [ + 304, + 451, + 380, + 498 + ], + "type": "image", + "image_path": "c2328f4c083ac74f2c2a991d1014b839d6f93caca949c146b6ec7a90159fdbed.jpg" + } + ] + } + ], + "index": 40, + "angle": 0, + "type": "image_body" + } + ], + "index": 40 + }, + { + "type": "image", + "bbox": [ + 304, + 510, + 380, + 585 + ], + "blocks": [ + { + "bbox": [ + 304, + 510, + 380, + 585 + ], + "lines": [ + { + "bbox": [ + 304, + 510, + 380, + 585 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 380, + 585 + ], + "type": "image", + "image_path": "225cf090e1996ed4cdd3121d861aa83f2b8417261eb64ecfd93cc7a20e7acf02.jpg" + } + ] + } + ], + "index": 41, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 313, + 587, + 371, + 598 + ], + "lines": [ + { + "bbox": [ + 313, + 587, + 371, + 598 + ], + "spans": [ + { + "bbox": [ + 313, + 587, + 371, + 598 + ], + "type": "text", + "content": "Our Sample 2" + } + ] + } + ], + "index": 42, + "angle": 0, + "type": "image_caption" + } + ], + "index": 41 + }, + { + "type": "image", + "bbox": [ + 388, + 451, + 463, + 499 + ], + "blocks": [ + { + "bbox": [ + 388, + 451, + 463, + 499 + ], + "lines": [ + { + "bbox": [ + 388, + 451, + 463, + 499 + ], + "spans": [ + { + "bbox": [ + 388, + 451, + 463, + 499 + ], + "type": "image", + "image_path": "0a3e9d834cf49ab30040649b7970ed1690dc6669521882bbaaf0674a53ddb1a3.jpg" + } + ] + } + ], + "index": 43, + "angle": 0, + "type": "image_body" + } + ], + "index": 43 + }, + { + "type": "image", + "bbox": [ + 389, + 510, + 463, + 585 + ], + "blocks": [ + { + "bbox": [ + 389, + 510, + 463, + 585 + ], + "lines": [ + { + "bbox": [ + 389, + 510, + 463, + 585 + ], + "spans": [ + { + "bbox": [ + 389, + 510, + 463, + 585 + ], + "type": "image", + "image_path": "e0a1ae028c9ca7ecd9a704888f1276391f3ea02ddd47db34de9fa42d326b775e.jpg" + } + ] + } + ], + "index": 44, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 397, + 587, + 454, + 598 + ], + "lines": [ + { + "bbox": [ + 397, + 587, + 454, + 598 + ], + "spans": [ + { + "bbox": [ + 397, + 587, + 454, + 598 + ], + "type": "text", + "content": "Our Sample 3" + } + ] + } + ], + "index": 45, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 186, + 609, + 405, + 620 + ], + "lines": [ + { + "bbox": [ + 186, + 609, + 405, + 620 + ], + "spans": [ + { + "bbox": [ + 186, + 609, + 405, + 620 + ], + "type": "text", + "content": "Figure 5: Qualitative results of diversity on NuScenes." + } + ] + } + ], + "index": 49, + "angle": 0, + "type": "image_caption" + } + ], + "index": 44 + }, + { + "type": "image", + "bbox": [ + 473, + 435, + 547, + 510 + ], + "blocks": [ + { + "bbox": [ + 473, + 435, + 547, + 510 + ], + "lines": [ + { + "bbox": [ + 473, + 435, + 547, + 510 + ], + "spans": [ + { + "bbox": [ + 473, + 435, + 547, + 510 + ], + "type": "image", + "image_path": "a7159444af1fcc0bdfc49e41d8b459001c907787a889b5e736fe00efd4e23d2e.jpg" + } + ] + } + ], + "index": 46, + "angle": 0, + "type": "image_body" + } + ], + "index": 46 + }, + { + "type": "image", + "bbox": [ + 473, + 510, + 547, + 585 + ], + "blocks": [ + { + "bbox": [ + 473, + 510, + 547, + 585 + ], + "lines": [ + { + "bbox": [ + 473, + 510, + 547, + 585 + ], + "spans": [ + { + "bbox": [ + 473, + 510, + 547, + 585 + ], + "type": "image", + "image_path": "6197df6b885b76d0627b30d1661d1dc12fbc18fa526987ef51cb8ad08044ae2a.jpg" + } + ] + } + ], + "index": 47, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 475, + 587, + 544, + 598 + ], + "lines": [ + { + "bbox": [ + 475, + 587, + 544, + 598 + ], + "spans": [ + { + "bbox": [ + 475, + 587, + 544, + 598 + ], + "type": "text", + "content": "Uncertainty Map" + } + ] + } + ], + "index": 48, + "angle": 0, + "type": "image_caption" + } + ], + "index": 47 + }, + { + "bbox": [ + 46, + 642, + 288, + 702 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 288, + 702 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 288, + 702 + ], + "type": "text", + "content": "where acc is the empirical accuracy, and conf is the estimated confidence for each bin, " + }, + { + "bbox": [ + 46, + 642, + 288, + 702 + ], + "type": "inline_equation", + "content": "n_b" + }, + { + "bbox": [ + 46, + 642, + 288, + 702 + ], + "type": "text", + "content": " is the # of samples per each bin and " + }, + { + "bbox": [ + 46, + 642, + 288, + 702 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 46, + 642, + 288, + 702 + ], + "type": "text", + "content": " is the total # of samples. ECE is an important metric in BEV map segmentation, as ignoring uncertainties can lead to bad consequences in driving planning. We gener" + } + ] + } + ], + "index": 50 + }, + { + "bbox": [ + 306, + 642, + 547, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 642, + 547, + 689 + ], + "spans": [ + { + "bbox": [ + 306, + 642, + 547, + 689 + ], + "type": "text", + "content": "ate 15 diverse outputs for every instance and use the mean as the confidence. The baseline model is trained end-to-end with cross-entropy loss, so the predictions produced by the softmax function are assumed to be the pseudo probabilities." + } + ] + } + ], + "index": 51 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8234" + } + ] + } + ], + "index": 52 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 69, + 116, + 195 + ], + "blocks": [ + { + "bbox": [ + 53, + 69, + 116, + 195 + ], + "lines": [ + { + "bbox": [ + 53, + 69, + 116, + 195 + ], + "spans": [ + { + "bbox": [ + 53, + 69, + 116, + 195 + ], + "type": "image", + "image_path": "4923dbae83ba9d325b35ff0f5a967f0c89c3a518cf70478d1aab7ed98c7044a7.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 69, + 206, + 100, + 217 + ], + "lines": [ + { + "bbox": [ + 69, + 206, + 100, + 217 + ], + "spans": [ + { + "bbox": [ + 69, + 206, + 100, + 217 + ], + "type": "text", + "content": "LiDAR" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 124, + 69, + 187, + 194 + ], + "blocks": [ + { + "bbox": [ + 124, + 69, + 187, + 194 + ], + "lines": [ + { + "bbox": [ + 124, + 69, + 187, + 194 + ], + "spans": [ + { + "bbox": [ + 124, + 69, + 187, + 194 + ], + "type": "image", + "image_path": "36bd2ed41022c4b45941e5e0b362513f447d1de006d59ce9a94862f6d85355fd.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 135, + 197, + 178, + 207 + ], + "lines": [ + { + "bbox": [ + 135, + 197, + 178, + 207 + ], + "spans": [ + { + "bbox": [ + 135, + 197, + 178, + 207 + ], + "type": "text", + "content": "Prediction" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 196, + 69, + 259, + 194 + ], + "blocks": [ + { + "bbox": [ + 196, + 69, + 259, + 194 + ], + "lines": [ + { + "bbox": [ + 196, + 69, + 259, + 194 + ], + "spans": [ + { + "bbox": [ + 196, + 69, + 259, + 194 + ], + "type": "image", + "image_path": "007f185348c48b58927f8ca278f458835c16eb4625a6379e33692aa2ab4bff99.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 204, + 197, + 251, + 208 + ], + "lines": [ + { + "bbox": [ + 204, + 197, + 251, + 208 + ], + "spans": [ + { + "bbox": [ + 204, + 197, + 251, + 208 + ], + "type": "text", + "content": "Uncertainty" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 198, + 213, + 258, + 224 + ], + "lines": [ + { + "bbox": [ + 198, + 213, + 258, + 224 + ], + "spans": [ + { + "bbox": [ + 198, + 213, + 258, + 224 + ], + "type": "text", + "content": "BEVFusion-C" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 268, + 69, + 331, + 194 + ], + "blocks": [ + { + "bbox": [ + 268, + 69, + 331, + 194 + ], + "lines": [ + { + "bbox": [ + 268, + 69, + 331, + 194 + ], + "spans": [ + { + "bbox": [ + 268, + 69, + 331, + 194 + ], + "type": "image", + "image_path": "dc5aaf86de4d38714bface5b89d7901bd31514f2effdb6580628cb1438e871ce.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 277, + 197, + 321, + 209 + ], + "lines": [ + { + "bbox": [ + 277, + 197, + 321, + 209 + ], + "spans": [ + { + "bbox": [ + 277, + 197, + 321, + 209 + ], + "type": "text", + "content": "Error Map" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 236, + 547, + 284 + ], + "lines": [ + { + "bbox": [ + 46, + 236, + 547, + 284 + ], + "spans": [ + { + "bbox": [ + 46, + 236, + 547, + 284 + ], + "type": "text", + "content": "Figure 6: Prediction, uncertainty, and error map comparison between BEVFusion-C and MapPrior. BEVFusion generates a misguided uncertainty boundary by giving high weight to areas where map elements are unlikely to be. In comparison, MapPrior's uncertainty is constrained to map element boundaries. This is further confirmed with the error map, where MapPrior's uncertainty map closely matches the error map." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 339, + 69, + 402, + 194 + ], + "blocks": [ + { + "bbox": [ + 339, + 69, + 402, + 194 + ], + "lines": [ + { + "bbox": [ + 339, + 69, + 402, + 194 + ], + "spans": [ + { + "bbox": [ + 339, + 69, + 402, + 194 + ], + "type": "image", + "image_path": "e5cdc9ad14a4d8f2babf0ae2a67e60ef3e14e81ef65dff7a611f96ef0d7ffb85.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 349, + 197, + 392, + 208 + ], + "lines": [ + { + "bbox": [ + 349, + 197, + 392, + 208 + ], + "spans": [ + { + "bbox": [ + 349, + 197, + 392, + 208 + ], + "type": "text", + "content": "Prediction" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 410, + 69, + 473, + 194 + ], + "blocks": [ + { + "bbox": [ + 410, + 69, + 473, + 194 + ], + "lines": [ + { + "bbox": [ + 410, + 69, + 473, + 194 + ], + "spans": [ + { + "bbox": [ + 410, + 69, + 473, + 194 + ], + "type": "image", + "image_path": "2e0d8852bf49a33ce7b9dd9e0cda87589ed9864567521be4667122d23cf8c05c.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 417, + 197, + 466, + 209 + ], + "lines": [ + { + "bbox": [ + 417, + 197, + 466, + 209 + ], + "spans": [ + { + "bbox": [ + 417, + 197, + 466, + 209 + ], + "type": "text", + "content": "Uncertainty" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 421, + 213, + 462, + 225 + ], + "lines": [ + { + "bbox": [ + 421, + 213, + 462, + 225 + ], + "spans": [ + { + "bbox": [ + 421, + 213, + 462, + 225 + ], + "type": "text", + "content": "MapPrior" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 482, + 69, + 545, + 194 + ], + "blocks": [ + { + "bbox": [ + 482, + 69, + 545, + 194 + ], + "lines": [ + { + "bbox": [ + 482, + 69, + 545, + 194 + ], + "spans": [ + { + "bbox": [ + 482, + 69, + 545, + 194 + ], + "type": "image", + "image_path": "866965474c9d5def163e49624c80ddd3e183bb1da3ca001d82c9b8387564d88a.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 491, + 197, + 535, + 209 + ], + "lines": [ + { + "bbox": [ + 491, + 197, + 535, + 209 + ], + "spans": [ + { + "bbox": [ + 491, + 197, + 535, + 209 + ], + "type": "text", + "content": "Error Map" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "table", + "bbox": [ + 52, + 324, + 282, + 381 + ], + "blocks": [ + { + "bbox": [ + 60, + 303, + 273, + 316 + ], + "lines": [ + { + "bbox": [ + 60, + 303, + 273, + 316 + ], + "spans": [ + { + "bbox": [ + 60, + 303, + 273, + 316 + ], + "type": "text", + "content": "Table 2: Ablation studies for MapPrior on nuScenes." + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 52, + 324, + 282, + 381 + ], + "lines": [ + { + "bbox": [ + 52, + 324, + 282, + 381 + ], + "spans": [ + { + "bbox": [ + 52, + 324, + 282, + 381 + ], + "type": "table", + "html": "
Output Loss LoutT(z') or T(z', x)mIoU (↑)MMD (↓)
-T(z')45.633.3
✓T(z')49.045.6
✓T(z', x)51.135.8
", + "image_path": "1de20aea8f05c9c46b0c044a8cbb1f6dd90be5b50db7915ceaad8c82824b5543.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "table_body" + } + ], + "index": 18 + }, + { + "bbox": [ + 46, + 412, + 288, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 412, + 288, + 460 + ], + "spans": [ + { + "bbox": [ + 46, + 412, + 288, + 460 + ], + "type": "text", + "content": "Baselines. For LiDAR-only segmentation, we use Point-Pillars [38], and BEVFusion-L [49, 80] as our baselines. To the best of our knowledge, BEVFusion-L is the current state-of-the-art method in LiDAR-based BEV map segmentation." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 46, + 460, + 287, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 460, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 46, + 460, + 287, + 533 + ], + "type": "text", + "content": "For camera-only segmentation, our baseline model are LSS [56], OFT [60], and BEVFusion-C [49]. Among them, BEVFusion-C is the current state-of-the-art model with a significantly higher IoU score than other methods. We use open-source code from BEVFusion. We also provide results of multi-modal models [49, 75, 81] for reference." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 46, + 545, + 288, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 545, + 288, + 665 + ], + "spans": [ + { + "bbox": [ + 46, + 545, + 288, + 665 + ], + "type": "text", + "content": "Implementation details. Following [49], we perform segmentation in a " + }, + { + "bbox": [ + 46, + 545, + 288, + 665 + ], + "type": "inline_equation", + "content": "[-50\\mathrm{m}, 50\\mathrm{m}] \\times [-50\\mathrm{m}, 50\\mathrm{m}]" + }, + { + "bbox": [ + 46, + 545, + 288, + 665 + ], + "type": "text", + "content": " region around the ego car with a resolution of 0.5 meters/pixel, resulting in a final image size of " + }, + { + "bbox": [ + 46, + 545, + 288, + 665 + ], + "type": "inline_equation", + "content": "200 \\times 200" + }, + { + "bbox": [ + 46, + 545, + 288, + 665 + ], + "type": "text", + "content": ". Since map classes may overlap, our model performs binary segmentation for all classes. The encoder and decoder comprise four downsampling and four upsampling blocks processing a series of 128-256-512-256-128 channels. Each block comprises 2 reset blocks and one convolution and uses sigmoid activation and GroupNorm. The resolution of the latent space is [12,12]." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 46, + 665, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 288, + 714 + ], + "type": "text", + "content": "For the generative step, we train a minGPT [30] transformer conditioned on the generated sequence, extracted BEV features, and the initial noisy map. We train the whole model using Adam [32] with a learning rate of 9.0e-6. The" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 304, + 547, + 376 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 304, + 547, + 376 + ], + "spans": [ + { + "bbox": [ + 304, + 304, + 547, + 376 + ], + "type": "text", + "content": "transformer's BEV feature encoder for the transformer has a similar structure to the model encoder consisting of 3 down-sampling blocks. The BEV feature encoder converts the original BEV features shaped [128, 128] into latent space tokens shaped [12, 12]. We apply a multiplier of 100 on the output loss to balance the magnitude of different losses." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 306, + 382, + 486, + 395 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 382, + 486, + 395 + ], + "spans": [ + { + "bbox": [ + 306, + 382, + 486, + 395 + ], + "type": "text", + "content": "4.2. Map Segmentation as Generation" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 304, + 400, + 547, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 400, + 547, + 590 + ], + "spans": [ + { + "bbox": [ + 304, + 400, + 547, + 590 + ], + "type": "text", + "content": "Quantitative results. We show our quantitative results for map segmentation in Tab. 1. The results show that MapPrior achieves state-of-the-art performance. Comparing with BEVFusion-L, our MapPrior-L offers " + }, + { + "bbox": [ + 304, + 400, + 547, + 590 + ], + "type": "inline_equation", + "content": "2.5\\%" + }, + { + "bbox": [ + 304, + 400, + 547, + 590 + ], + "type": "text", + "content": " improvement in mIoU, which is brought purely by our proposed generative stage. Furthermore, MapPrior provides a substantial improvement in the MMD score compared to baselines. MMD is a metric of distance between the generated layout predictions and the ground truth distribution. This shows that MapPrior's outputs closely match the ground truth data distribution. In addition, this stark difference in MapPrior's MMD performance compared to the baselines implies that the realism metric and precision metric are not closely coupled. It is possible to achieve higher IoU while generating non-realistic samples, or vice versa. Our approach simultaneously pushes the limit of the two." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 304, + 592, + 547, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 592, + 547, + 676 + ], + "spans": [ + { + "bbox": [ + 304, + 592, + 547, + 676 + ], + "type": "text", + "content": "Moreover, inference speed is vital for MapPrior. Using an RTX A6000 GPU, we compared the inference speeds of our model and BEVFusion in terms of frames per second (FPS). Our findings are presented in Tab. 3. These results indicate that one-step MapPrior is significantly closer to real-time performance compared to the standard MapPrior, with only a minor trade-off in IoU for increased uncertainty awareness." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "type": "text", + "content": "Qualitative results. We show our qualitative results in Fig. 4. Compared to other methods, MapPrior can consist" + } + ] + } + ], + "index": 27 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8235" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 85, + 68, + 509, + 170 + ], + "blocks": [ + { + "bbox": [ + 85, + 68, + 509, + 170 + ], + "lines": [ + { + "bbox": [ + 85, + 68, + 509, + 170 + ], + "spans": [ + { + "bbox": [ + 85, + 68, + 509, + 170 + ], + "type": "image", + "image_path": "2b991d78bdfd586d60cb83d7c6a8fe1597c651151e1d79e7bb8489f387f11cdc.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 107, + 177, + 485, + 190 + ], + "lines": [ + { + "bbox": [ + 107, + 177, + 485, + 190 + ], + "spans": [ + { + "bbox": [ + 107, + 177, + 485, + 190 + ], + "type": "text", + "content": "Figure 7: Results for perpetual traffic scene generation. Two road subsections are shown here." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 48, + 221, + 288, + 355 + ], + "blocks": [ + { + "bbox": [ + 77, + 201, + 256, + 213 + ], + "lines": [ + { + "bbox": [ + 77, + 201, + 256, + 213 + ], + "spans": [ + { + "bbox": [ + 77, + 201, + 256, + 213 + ], + "type": "text", + "content": "Table 3: Performance of one-step MapPrior." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 221, + 288, + 355 + ], + "lines": [ + { + "bbox": [ + 48, + 221, + 288, + 355 + ], + "spans": [ + { + "bbox": [ + 48, + 221, + 288, + 355 + ], + "type": "table", + "html": "
ModalitymIoU (↑)MMD (↓)FPS
BEVFusion-C [49]C56.639.68.85
MapPrior-CC56.728.40.60
MapPrior-C (1 step)C56.728.74.26
BEVFusion-L [80, 49]L48.6115.27.52
MapPrior-LL51.135.80.57
MapPrior-L (1 step)L50.050.24.88
BEVFusion [49]C+L62.721.65.52
MapPrior-CLC+L63.128.00.55
MapPrior-CL (1 step)C+L63.028.13.61
", + "image_path": "4f7fc4bd874aa545cda7707971eaf0013ea513cb52d72bcf4e206ee218887927.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_body" + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 375, + 287, + 494 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 375, + 287, + 494 + ], + "spans": [ + { + "bbox": [ + 46, + 375, + 287, + 494 + ], + "type": "text", + "content": "tently generate coherent and realistic class predictions within the entire map region. Our model has a more coherent divider layout, whereas the baseline methods usually have broken/missing lane dividers. In the baseline methods, the stopline is often jagged and appears disconnected from the road. In distant areas from the ego car, our model tries to make a plausible layout estimate when other methods fail due to limited observations (this is especially noticeable in the pedestrian walkways). The edges from our method are also more smooth, resulting in a more realistic estimation." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 514, + 287, + 561 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 514, + 287, + 561 + ], + "spans": [ + { + "bbox": [ + 46, + 514, + 287, + 561 + ], + "type": "text", + "content": "Diversity and uncertainty calibration. We show that our model can produce a better-calibrated layout with diversity. In Fig. 5, we show that our model can generate multiple diverse and feasible layouts, All of which are realistic." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 562, + 287, + 635 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 562, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 46, + 562, + 287, + 635 + ], + "type": "text", + "content": "By aggregating the diverse samples, our model can produce a calibrated uncertainty map. We show our results in Fig. 6. Compared to the baselines (which are unable to generate multiple samples), our uncertainty map aligns with the error map much more accurately. ECE scores in Tab. 1 further validate this quantitatively." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 654, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 654, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 654, + 288, + 715 + ], + "type": "text", + "content": "Perpetual generation. We show our qualitative results for generating 'infinite' roads in Fig. 7. We have generated a single " + }, + { + "bbox": [ + 46, + 654, + 288, + 715 + ], + "type": "inline_equation", + "content": "30\\mathrm{km}" + }, + { + "bbox": [ + 46, + 654, + 288, + 715 + ], + "type": "text", + "content": " long road. Due to size constraints, we are only able to show a subsection. The generated traffic scene contains a highway with intermittent intersections resembling a" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 202, + 545, + 227 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 202, + 545, + 227 + ], + "spans": [ + { + "bbox": [ + 304, + 202, + 545, + 227 + ], + "type": "text", + "content": "road layout in a city. We provide the entire road as a gif in our supplementary materials." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 232, + 382, + 243 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 232, + 382, + 243 + ], + "spans": [ + { + "bbox": [ + 306, + 232, + 382, + 243 + ], + "type": "text", + "content": "4.3. Discussions" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 251, + 547, + 346 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 251, + 547, + 346 + ], + "spans": [ + { + "bbox": [ + 304, + 251, + 547, + 346 + ], + "type": "text", + "content": "Ablation studies. To justify our design, we provide ablation studies in Tab. 2. L2 loss at the output end changes the model's optimization target. It puts more weight on generating accurate results as opposed to generating i.i.d. data. Therefore, the model achieves a higher IoU score at the cost of a slightly worse MMD. Providing the transformer with BEV features boosts the performance by around " + }, + { + "bbox": [ + 304, + 251, + 547, + 346 + ], + "type": "inline_equation", + "content": "3\\%" + }, + { + "bbox": [ + 304, + 251, + 547, + 346 + ], + "type": "text", + "content": " in the IoU score, and decreases MMD by around " + }, + { + "bbox": [ + 304, + 251, + 547, + 346 + ], + "type": "inline_equation", + "content": "21\\%" + }, + { + "bbox": [ + 304, + 251, + 547, + 346 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 360, + 547, + 515 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 360, + 547, + 515 + ], + "spans": [ + { + "bbox": [ + 304, + 360, + 547, + 515 + ], + "type": "text", + "content": "Inference speed. Inference speed is essential for MapPrior, especially given the real-time demands of autonomous driving. While transformers offer remarkable generative abilities, they inherently slow down performance due to their sequential token generation process. Moreover, the need for MapPrior to produce diverse outcomes further curtails its inference speed. To address this, we introduced the one-step variant of MapPrior, which predicts a single sample for each input and generates all tokens simultaneously. As evidenced in Tab. 3, the one-step MapPrior registers a marginally worse MMD score and falls short in uncertainty awareness. Nonetheless, the one-step MapPrior markedly outpaces the standard MapPrior in speed." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 524, + 378, + 536 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 524, + 378, + 536 + ], + "spans": [ + { + "bbox": [ + 306, + 524, + 378, + 536 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 544, + 547, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 544, + 547, + 640 + ], + "spans": [ + { + "bbox": [ + 304, + 544, + 547, + 640 + ], + "type": "text", + "content": "This paper presents MapPrior, a novel generative method for performing BEV perception. The core idea is to leverage a learned generative prior over traffic layouts to provide diverse and accurate layout estimations, which potentially enable more informed decision-making and motion planning. Our experiments show that our approach produces more realistic scene layouts, enhances accuracy, and better calibrates uncertainty compared to current methods." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 654, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 547, + 713 + ], + "type": "text", + "content": "Acknowledgement. The project is partially funded by the Illinois Smart Transportation Initiative STII-21-07, an Amazon Research Award, an Intel Research Gift, and an IBM IIDAI grant. We also thank NVIDIA for the Academic Hardware Grant. VZ is supported by the Frontier Fellowship." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8236" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 712 + ], + "type": "list", + "angle": 0, + "index": 20, + "blocks": [ + { + "bbox": [ + 53, + 91, + 288, + 113 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 288, + 113 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 288, + 113 + ], + "type": "text", + "content": "[1] Martin Arjovsky, Soumith Chintala, and Léon Bottou. Wasserstein generative adversarial networks. In ICML, 2017. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 115, + 288, + 158 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 115, + 288, + 158 + ], + "spans": [ + { + "bbox": [ + 53, + 115, + 288, + 158 + ], + "type": "text", + "content": "[2] Xuyang Bai, Zeyu Hu, Xinge Zhu, Qingqiu Huang, Yilun Chen, Hongbo Fu, and Chiew-Lan Tai. Transfusion: Robust lidar-camera fusion for 3d object detection with transformers. In CVPR, 2022. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 160, + 288, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 160, + 288, + 194 + ], + "spans": [ + { + "bbox": [ + 53, + 160, + 288, + 194 + ], + "type": "text", + "content": "[3] Connelly Barnes, Eli Shechtman, Adam Finkelstein, and Dan B Goldman. PatchMatch: A randomized correspondence algorithm for structural image editing. 2009. 5" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 195, + 287, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 195, + 287, + 228 + ], + "spans": [ + { + "bbox": [ + 53, + 195, + 287, + 228 + ], + "type": "text", + "content": "[4] Ioan Andrei Barsan, Shenlong Wang, Andrei Pokrovsky, and Raquel Urtasun. Learning to localize using a lidar intensity map. In CoRL, 2018. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 230, + 287, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 230, + 287, + 262 + ], + "spans": [ + { + "bbox": [ + 53, + 230, + 287, + 262 + ], + "type": "text", + "content": "[5] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. In ICLR, 2019. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 264, + 288, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 264, + 288, + 308 + ], + "spans": [ + { + "bbox": [ + 53, + 264, + 288, + 308 + ], + "type": "text", + "content": "[6] Holger Caesar, Varun Bankiti, Alex H. Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In CVPR, 2020. 6" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 309, + 288, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 309, + 288, + 342 + ], + "spans": [ + { + "bbox": [ + 53, + 309, + 288, + 342 + ], + "type": "text", + "content": "[7] Sergio Casas, Wenjie Luo, and Raquel Urtasun. Intentnet: Learning to predict intention from raw sensor data. In CoRL, 2018. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 344, + 288, + 376 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 344, + 288, + 376 + ], + "spans": [ + { + "bbox": [ + 53, + 344, + 288, + 376 + ], + "type": "text", + "content": "[8] Sergio Casas, Abbas Sadat, and Raquel Urtasun. Mp3: A unified model to map, perceive, predict and plan. In CVPR, 2021. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 379, + 288, + 411 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 379, + 288, + 411 + ], + "spans": [ + { + "bbox": [ + 53, + 379, + 288, + 411 + ], + "type": "text", + "content": "[9] Huiwen Chang, Han Zhang, Lu Jiang, Ce Liu, and William T. Freeman. Maskgit: Masked generative image transformer. In CVPR, 2022. 2, 3, 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 414, + 288, + 446 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 414, + 288, + 446 + ], + "spans": [ + { + "bbox": [ + 48, + 414, + 288, + 446 + ], + "type": "text", + "content": "[10] Bowen Cheng, Alexander G. Schwing, and Alexander Kirillov. Per-pixel classification is not all you need for semantic segmentation. In NeurIPS, 2021. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 449, + 288, + 480 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 449, + 288, + 480 + ], + "spans": [ + { + "bbox": [ + 48, + 449, + 288, + 480 + ], + "type": "text", + "content": "[11] Kashyap Chitta, Aditya Prakash, and Andreas Geiger. Neat: Neural attention fields for end-to-end autonomous driving. In CVPR, 2021. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 483, + 288, + 504 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 483, + 288, + 504 + ], + "spans": [ + { + "bbox": [ + 48, + 483, + 288, + 504 + ], + "type": "text", + "content": "[12] Min Jin Chong and David Forsyth. Jojogan: One shot face stylization. In ECCV, 2022. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 506, + 288, + 539 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 506, + 288, + 539 + ], + "spans": [ + { + "bbox": [ + 48, + 506, + 288, + 539 + ], + "type": "text", + "content": "[13] Laurene Claussmann, Marc Revilloud, Dominique Gruyer, and Sébastien Glaser. A review of motion planning for highway autonomous driving. 2020. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 540, + 288, + 562 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 540, + 288, + 562 + ], + "spans": [ + { + "bbox": [ + 48, + 540, + 288, + 562 + ], + "type": "text", + "content": "[14] Prafulla Dhariwal and Alex Nichol. Diffusion models beat gans on image synthesis. In NeurIPS, 2021. 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 564, + 288, + 596 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 564, + 288, + 596 + ], + "spans": [ + { + "bbox": [ + 48, + 564, + 288, + 596 + ], + "type": "text", + "content": "[15] Laurent Dinh, David Krueger, and Yoshua Bengio. Nice: Non-linear independent components estimation. In ICLR (Workshop), 2014. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 598, + 288, + 631 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 598, + 288, + 631 + ], + "spans": [ + { + "bbox": [ + 48, + 598, + 288, + 631 + ], + "type": "text", + "content": "[16] Shivam Duggal, Shenlong Wang, Wei-Chiu Ma, Rui Hu, and Raquel Urtasun. Deepruner: Learning efficient stereo matching via differentiable patchmatch. In ICCV, 2019. 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 48, + 633, + 288, + 655 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 633, + 288, + 655 + ], + "spans": [ + { + "bbox": [ + 48, + 633, + 288, + 655 + ], + "type": "text", + "content": "[17] Alexei A. Efros and William T. Freeman. Image quilting for texture synthesis and transfer. In SIGGRAPH, 2001. 5" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 48, + 657, + 288, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 657, + 288, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 657, + 288, + 689 + ], + "type": "text", + "content": "[18] Patrick Esser, Robin Rombach, and Björn Ommer. Taming transformers for high-resolution image synthesis. In CVPR, 2021. 2, 3, 4, 5" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 48, + 691, + 288, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 288, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 288, + 712 + ], + "type": "text", + "content": "[19] W.T. Freeman and E.C. Pasztor. Learning low-level vision. In CVPR, 1999. 3" + } + ] + } + ], + "index": 19 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 712 + ], + "type": "list", + "angle": 0, + "index": 41, + "blocks": [ + { + "bbox": [ + 307, + 73, + 547, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 547, + 116 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 547, + 116 + ], + "type": "text", + "content": "[20] Ian J. Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. In NeurIPS, 2014. 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 118, + 547, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 547, + 139 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 547, + 139 + ], + "type": "text", + "content": "[21] Nikhil Gosala and Abhinav Valada. Bird's-eye-view panoptic segmentation using monocular frontal view images. 2022. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 141, + 547, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 141, + 547, + 161 + ], + "spans": [ + { + "bbox": [ + 307, + 141, + 547, + 161 + ], + "type": "text", + "content": "[22] Chuan Guo, Geoff Pleiss, Yu Sun, and Kilian Q. Weinberger. On calibration of modern neural networks. In ICML, 2017. 6" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 163, + 546, + 195 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 163, + 546, + 195 + ], + "spans": [ + { + "bbox": [ + 307, + 163, + 546, + 195 + ], + "type": "text", + "content": "[23] Agrim Gupta, Justin Johnson, Li Fei-Fei, Silvio Savarese, and Alexandre Alahi. Social gan: Socially acceptable trajectories with generative adversarial networks. In CVPR, 2018. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 197, + 547, + 218 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 197, + 547, + 218 + ], + "spans": [ + { + "bbox": [ + 307, + 197, + 547, + 218 + ], + "type": "text", + "content": "[24] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. In NeurIPS, 2020. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 220, + 547, + 251 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 220, + 547, + 251 + ], + "spans": [ + { + "bbox": [ + 307, + 220, + 547, + 251 + ], + "type": "text", + "content": "[25] Ari Holtzman, Jan Buys, Li Du, Maxwell Forbes, and Yejin Choi. The curious case of neural text degeneration. In ICLR, 2020. 4" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 253, + 546, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 253, + 546, + 297 + ], + "spans": [ + { + "bbox": [ + 307, + 253, + 546, + 297 + ], + "type": "text", + "content": "[26] Anthony Hu, Zak Murez, Nikhil Mohan, Sofia Dudas, Jeffrey Hawke, Vijay Badrinarayanan, Roberto Cipolla, and Alex Kendall. FIERY: Future instance segmentation in bird's-eye view from surround monocular cameras. In ICCV, 2021. 2" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 298, + 547, + 341 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 298, + 547, + 341 + ], + "spans": [ + { + "bbox": [ + 307, + 298, + 547, + 341 + ], + "type": "text", + "content": "[27] Junjie Huang, Guan Huang, Zheng Zhu, and Dalong Du. BEVDet: High-Performance Multi-Camera 3D Object Detection in Bird-Eye-View. arXiv preprint arXiv:2112.11790, 2021. 2" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 343, + 547, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 343, + 547, + 374 + ], + "spans": [ + { + "bbox": [ + 307, + 343, + 547, + 374 + ], + "type": "text", + "content": "[28] Phillip Isola, Jun-Yan Zhu, Tinghui Zhou, and Alexei A. Efros. Image-to-image translation with conditional adversarial networks. In CVPR, 2017. 2, 3" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 376, + 547, + 398 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 376, + 547, + 398 + ], + "spans": [ + { + "bbox": [ + 307, + 376, + 547, + 398 + ], + "type": "text", + "content": "[29] Eric Jang, Shixiang Gu, and Ben Poole. Categorical Reparaterization with Gumbel-Softmax. In ICLR, 2017. 5" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 307, + 399, + 546, + 420 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 399, + 546, + 420 + ], + "spans": [ + { + "bbox": [ + 307, + 399, + 546, + 420 + ], + "type": "text", + "content": "[30] Andrej Karpathy. Mingpt. https://github.com/karpathy/minGPT, 2022.8" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 307, + 422, + 546, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 422, + 546, + 453 + ], + "spans": [ + { + "bbox": [ + 307, + 422, + 546, + 453 + ], + "type": "text", + "content": "[31] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In CVPR, 2019. 2" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 307, + 456, + 546, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 456, + 546, + 487 + ], + "spans": [ + { + "bbox": [ + 307, + 456, + 546, + 487 + ], + "type": "text", + "content": "[32] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. 8" + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 307, + 489, + 546, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 489, + 546, + 510 + ], + "spans": [ + { + "bbox": [ + 307, + 489, + 546, + 510 + ], + "type": "text", + "content": "[33] Diederik P. Kingma and Prafulla Dhariwal. Glow: Generative flow with invertible 1x1 convolutions. In NeurIPS, 2018. 2" + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 307, + 512, + 546, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 512, + 546, + 533 + ], + "spans": [ + { + "bbox": [ + 307, + 512, + 546, + 533 + ], + "type": "text", + "content": "[34] Diederik P Kingma and Max Welling. Auto-encoding variational bayes. In ICLR, 2014. 2" + } + ] + } + ], + "index": 35 + }, + { + "bbox": [ + 307, + 535, + 546, + 567 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 535, + 546, + 567 + ], + "spans": [ + { + "bbox": [ + 307, + 535, + 546, + 567 + ], + "type": "text", + "content": "[35] Philipp Kähenbuhl and Vladlen Koltun. Efficient inference in fully connected crfs with gaussian edge potentials. In NeurIPS, 2011. 3" + } + ] + } + ], + "index": 36 + }, + { + "bbox": [ + 307, + 568, + 546, + 590 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 568, + 546, + 590 + ], + "spans": [ + { + "bbox": [ + 307, + 568, + 546, + 590 + ], + "type": "text", + "content": "[36] Ananya Kumar, Percy Liang, and Tengyu Ma. Verified uncertainty calibration. In NeurIPS, 2019. 6" + } + ] + } + ], + "index": 37 + }, + { + "bbox": [ + 307, + 591, + 546, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 591, + 546, + 624 + ], + "spans": [ + { + "bbox": [ + 307, + 591, + 546, + 624 + ], + "type": "text", + "content": "[37] Markus Kängsepp and Meelis Kull. Calibrated perception uncertainty across objects and regions in bird's-eye-view. In NeurIPS (Workshop), 2022. 2" + } + ] + } + ], + "index": 38 + }, + { + "bbox": [ + 307, + 625, + 546, + 666 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 625, + 546, + 666 + ], + "spans": [ + { + "bbox": [ + 307, + 625, + 546, + 666 + ], + "type": "text", + "content": "[38] Alex H. Lang, Sourabh Vora, Holger Caesar, Lubing Zhou, Jiong Yang, and Oscar Beijbom. Pointpillars: Fast encoders for object detection from point clouds. In CVPR, 2019. 2, 6, 8" + } + ] + } + ], + "index": 39 + }, + { + "bbox": [ + 307, + 670, + 546, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 670, + 546, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 670, + 546, + 712 + ], + "type": "text", + "content": "[39] Jesse Levinson, Jake Askeland, Jan Becker, Jennifer Dolson, David Held, Soeren Kammel, J. Zico Kolter, Dirk Langer, Oliver Pink, Vaughan Pratt, Michael Sokolsky, Ganymed Stanek, David Stavens, Alex Teichman, Moritz Werling, and" + } + ] + } + ], + "index": 40 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8237" + } + ] + } + ], + "index": 42 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 18, + "blocks": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "text", + "content": "Sebastian Thrun. Towards fully autonomous driving: Systems and algorithms. In IV, 2011. 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 95, + 287, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 95, + 287, + 128 + ], + "spans": [ + { + "bbox": [ + 48, + 95, + 287, + 128 + ], + "type": "text", + "content": "[40] Jesse Levinson and Sebastian Thrun. Robust vehicle localization in urban environments using probabilistic maps. In ICRA, 2010. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 128, + 288, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 128, + 288, + 173 + ], + "spans": [ + { + "bbox": [ + 48, + 128, + 288, + 173 + ], + "type": "text", + "content": "[41] Daiqing Li, Junlin Yang, Karsten Kreis, Antonio Torralba, and Sanja Fidler. Semantic segmentation with generative models: Semi-supervised learning and strong out-of-domain generalization. In CVPR, 2021. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 173, + 288, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 173, + 288, + 205 + ], + "spans": [ + { + "bbox": [ + 48, + 173, + 288, + 205 + ], + "type": "text", + "content": "[42] Qi Li, Yue Wang, Yilun Wang, and Hang Zhao. Hdmapnet: An online hd map construction and evaluation framework. In ICRA, 2022. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 205, + 288, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 205, + 288, + 239 + ], + "spans": [ + { + "bbox": [ + 48, + 205, + 288, + 239 + ], + "type": "text", + "content": "[43] Ming Liang, Bin Yang, Rui Hu, Yun Chen, Renjie Liao, Song Feng, and Raquel Urtasun. Learning lane graph representations for motion forecasting. In ECCV, 2020. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 239, + 288, + 271 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 239, + 288, + 271 + ], + "spans": [ + { + "bbox": [ + 48, + 239, + 288, + 271 + ], + "type": "text", + "content": "[44] Ming Liang, Bin Yang, Shenlong Wang, and Raquel Urtasun. Deep continuous fusion for multi-sensor 3d object detection. In ECCV, 2018. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 272, + 288, + 316 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 272, + 288, + 316 + ], + "spans": [ + { + "bbox": [ + 48, + 272, + 288, + 316 + ], + "type": "text", + "content": "[45] Andrew Liu, Richard Tucker, Varun Jampani, Ameesh Makadia, Noah Snavely, and Angjoo Kanazawa. Infinite nature: Perpetual view generation of natural scenes from a single image. In ICCV, 2021. 5" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 316, + 288, + 348 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 316, + 288, + 348 + ], + "spans": [ + { + "bbox": [ + 48, + 316, + 288, + 348 + ], + "type": "text", + "content": "[46] Yingfei Liu, Tiancai Wang, Xiangyu Zhang, and Jian Sun. Petr: Position embedding transformation for multi-view 3d object detection. In ECCV, 2022. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 349, + 288, + 382 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 349, + 288, + 382 + ], + "spans": [ + { + "bbox": [ + 48, + 349, + 288, + 382 + ], + "type": "text", + "content": "[47] Yicheng Liu, Yuan Yuantian, Yue Wang, Yilun Wang, and Hang Zhao. Vectormapnet: End-to-end vectorized hd map learning. arXiv preprint arXiv:2206.08920, 2022. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 383, + 288, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 383, + 288, + 426 + ], + "spans": [ + { + "bbox": [ + 48, + 383, + 288, + 426 + ], + "type": "text", + "content": "[48] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin Transformer: Hierarchical Vision Transformer using Shifted Windows. In ICCV, 2021. 4" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 426, + 288, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 426, + 288, + 470 + ], + "spans": [ + { + "bbox": [ + 48, + 426, + 288, + 470 + ], + "type": "text", + "content": "[49] Zhijian Liu, Haotian Tang, Alexander Amini, Xinyu Yang, Huizi Mao, Daniela Rus, and Song Han. Bevfusion: Multi-task multi-sensor fusion with unified bird's-eye view representation. In ICRA, 2023. 1, 2, 3, 4, 6, 8, 9" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 471, + 288, + 503 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 471, + 288, + 503 + ], + "spans": [ + { + "bbox": [ + 48, + 471, + 288, + 503 + ], + "type": "text", + "content": "[50] W. Luo, B. Yang, and R. Urtasun. Fast and furious: Real time end-to-end 3d detection, tracking and motion forecasting with a single convolutional net. In CVPR, 2018. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 503, + 288, + 536 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 503, + 288, + 536 + ], + "spans": [ + { + "bbox": [ + 48, + 503, + 288, + 536 + ], + "type": "text", + "content": "[51] Jiageng Mao, Yujing Xue, Minzhe Niu, Haoyue Bai, Jiashi Feng, Xiaodan Liang, Hang Xu, and Chunjing Xu. Voxel transformer for 3d object detection. In CVPR, 2021. 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 537, + 288, + 569 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 537, + 288, + 569 + ], + "spans": [ + { + "bbox": [ + 48, + 537, + 288, + 569 + ], + "type": "text", + "content": "[52] Gellert Mattyus, Shenlong Wang, Sanja Fidler, and Raquel Urtasun. Hd maps: Fine-grained road segmentation by parsing ground and aerial images. In CVPR, 2016. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 570, + 288, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 570, + 288, + 602 + ], + "spans": [ + { + "bbox": [ + 48, + 570, + 288, + 602 + ], + "type": "text", + "content": "[53] Andrew Ng and Michael Jordan. On discriminative vs. generative classifiers: A comparison of logistic regression and naive bayes. In NeurIPS, 2001. 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 603, + 288, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 603, + 288, + 645 + ], + "spans": [ + { + "bbox": [ + 48, + 603, + 288, + 645 + ], + "type": "text", + "content": "[54] Taesung Park, Jun-Yan Zhu, Oliver Wang, Jingwan Lu, Eli Shechtman, Alexei A. Efros, and Richard Zhang. Swapping autoencoder for deep image manipulation. In NeurIPS, 2020. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 647, + 288, + 680 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 288, + 680 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 288, + 680 + ], + "type": "text", + "content": "[55] Niki Parmar, Ashish Vaswani, Jakob Uszkoreit, Lukasz Kaiser, Noam Shazeer, Alexander Ku, and Dustin Tran. Image transformer. In ICML, 2018. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 48, + 681, + 288, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 681, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 681, + 288, + 713 + ], + "type": "text", + "content": "[56] Jonah Philion and Sanja Fidler. Lift, splat, shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3d. In ECCV, 2020. 1, 2, 3, 4, 6, 8" + } + ] + } + ], + "index": 17 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 36, + "blocks": [ + { + "bbox": [ + 307, + 73, + 547, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 547, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 547, + 106 + ], + "type": "text", + "content": "[57] Aditya Prakash, Kashyap Chitta, and Andreas Geiger. Multimodal fusion transformer for end-to-end autonomous driving. In CVPR, 2021. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 107, + 547, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 547, + 140 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 547, + 140 + ], + "type": "text", + "content": "[58] Marc'Aurelio Ranzato, Joshua Sussekind, Volodymyr Mnih, and Geoffrey Hinton. On deep generative models with applications to recognition. In CVPR, 2011. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 141, + 547, + 175 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 141, + 547, + 175 + ], + "spans": [ + { + "bbox": [ + 307, + 141, + 547, + 175 + ], + "type": "text", + "content": "[59] Cody Reading, Ali Harakeh, Julia Chae, and Steven L Waslander. Categorical depth distribution network for monocular 3d object detection. In CVPR, 2021. 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 176, + 547, + 209 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 176, + 547, + 209 + ], + "spans": [ + { + "bbox": [ + 307, + 176, + 547, + 209 + ], + "type": "text", + "content": "[60] Thomas Roddick, Alex Kendall, and Roberto Cipolla. Orthographic feature transform for monocular 3d object detection. In BMVC, 2019. 2, 6, 8" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 210, + 547, + 243 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 210, + 547, + 243 + ], + "spans": [ + { + "bbox": [ + 307, + 210, + 547, + 243 + ], + "type": "text", + "content": "[61] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In CVPR, 2022. 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 245, + 547, + 278 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 245, + 547, + 278 + ], + "spans": [ + { + "bbox": [ + 307, + 245, + 547, + 278 + ], + "type": "text", + "content": "[62] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In MICCAI, 2015. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 280, + 547, + 302 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 280, + 547, + 302 + ], + "spans": [ + { + "bbox": [ + 307, + 280, + 547, + 302 + ], + "type": "text", + "content": "[63] S. Roth and M.J. Black. Fields of experts: a framework for learning image priors. In CVPR, 2005. 3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 304, + 547, + 336 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 304, + 547, + 336 + ], + "spans": [ + { + "bbox": [ + 307, + 304, + 547, + 336 + ], + "type": "text", + "content": "[64] Tim Salzmann, Boris Ivanovic, Punarjay Chakravarty, and Marco Pavone. Trajectory: Dynamically-feasible trajectory forecasting with heterogeneous data. In ECCV, 2020. 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 338, + 547, + 371 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 338, + 547, + 371 + ], + "spans": [ + { + "bbox": [ + 307, + 338, + 547, + 371 + ], + "type": "text", + "content": "[65] Yuan Shen, Wei-Chiu Ma, and Shenlong Wang. SGAM: Building a virtual 3d world through simultaneous generation and mapping. In NeurIPS, 2022. 5" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 373, + 547, + 406 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 373, + 547, + 406 + ], + "spans": [ + { + "bbox": [ + 307, + 373, + 547, + 406 + ], + "type": "text", + "content": "[66] Jianbo Shi and J. Malik. Normalized cuts and image segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 22(8):888-905, 2000. 3" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 407, + 547, + 452 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 407, + 547, + 452 + ], + "spans": [ + { + "bbox": [ + 307, + 407, + 547, + 452 + ], + "type": "text", + "content": "[67] Shaoshuai Shi, Li Jiang, Jiajun Deng, Zhe Wang, Chaoxu Guo, Jianping Shi, Xiaogang Wang, and Hongsheng Li. Pvrccnn++: Point-voxel feature set abstraction with local vector representation for 3d object detection. Springer, 2023. 2" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 453, + 547, + 485 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 453, + 547, + 485 + ], + "spans": [ + { + "bbox": [ + 307, + 453, + 547, + 485 + ], + "type": "text", + "content": "[68] Shaoshuai Shi, Xiaogang Wang, and Hongsheng Li. Pointr-cnn: 3d object proposal generation and detection from point cloud. In CVPR, 2019. 2" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 307, + 487, + 547, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 487, + 547, + 510 + ], + "spans": [ + { + "bbox": [ + 307, + 487, + 547, + 510 + ], + "type": "text", + "content": "[69] Nitish Srivastava and Russ R Salakhutdinov. Multimodal learning with deep boltzmann machines. In NeurIPS, 2012. 2" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 307, + 510, + 547, + 543 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 510, + 547, + 543 + ], + "spans": [ + { + "bbox": [ + 307, + 510, + 547, + 543 + ], + "type": "text", + "content": "[70] Deqing Sun, Stefan Roth, and Michael J. Black. Secrets of optical flow estimation and their principles. In CVPR, 2010. 3" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 307, + 545, + 547, + 655 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 545, + 547, + 655 + ], + "spans": [ + { + "bbox": [ + 307, + 545, + 547, + 655 + ], + "type": "text", + "content": "[71] Sebastian Thrun, Mike Montemerlo, Hendrik Dahlkamp, David Stavens, Andrei Aron, James Diebel, Philip Fong, John Gale, Morgan Halpenny, Gabriel Hoffmann, Kenny Lau, Celia Oakley, Mark Palatucci, Vaughan Pratt, Pascal Stang, Sven Strohband, Cedric Dupont, Lars-Erik Jendrossek, Christian Koelen, Charles Markey, Carlo Rummel, Joe van Niekerk, Eric Jensen, Philippe Alessandrini, Gary Bradski, Bob Davies, Scott Ettinger, Adrian Kaehler, Ara Nefian, and Pamela Mahoney. Stanley: The Robot That Won the DARPA Grand Challenge. 2007. 2" + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 307, + 656, + 547, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 656, + 547, + 689 + ], + "spans": [ + { + "bbox": [ + 307, + 656, + 547, + 689 + ], + "type": "text", + "content": "[72] Hung-Yu Tseng, Lu Jiang, Ce Liu, Ming-Hsuan Yang, and Weilong Yang. Regularizing generative adversarial networks under limited data. In CVPR, 2021. 2" + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 307, + 690, + 547, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 690, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 690, + 547, + 713 + ], + "type": "text", + "content": "[73] Arash Vahdat and Jan Kautz. Nvae: A deep hierarchical variational autoencoder. In NeurIPS, 2020. 2" + } + ] + } + ], + "index": 35 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8238" + } + ] + } + ], + "index": 37 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 73, + 288, + 636 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 48, + 73, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 73, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 48, + 73, + 287, + 95 + ], + "type": "text", + "content": "[74] Aaron van den Oord, Oriol Vinyals, and Koray Kavukcuoglu. Neural discrete representation learning. In NeurIPS, 2017. 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 288, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 288, + 128 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 288, + 128 + ], + "type": "text", + "content": "[75] Sourabh Vora, Alex H. Lang, Bassam Helou, and Oscar Bei-jbom. Pointpainting: Sequential fusion for 3d object detection. In CVPR, 2020. 2, 6, 8" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 130, + 288, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 130, + 288, + 184 + ], + "spans": [ + { + "bbox": [ + 48, + 130, + 288, + 184 + ], + "type": "text", + "content": "[76] Enze Xie, Zhiding Yu, Daquan Zhou, Jonah Philion, Anima Anandkumar, Sanja Fidler, Ping Luo, and Jose M. Alvarez. " + }, + { + "bbox": [ + 48, + 130, + 288, + 184 + ], + "type": "inline_equation", + "content": "\\mathbf{M}^2" + }, + { + "bbox": [ + 48, + 130, + 288, + 184 + ], + "type": "text", + "content": "bev: Multi-camera joint 3d detection and segmentation with unified birds-eye view representation. arXiv preprint arXiv:2204.05088, 2022. 2, 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 186, + 288, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 186, + 288, + 217 + ], + "spans": [ + { + "bbox": [ + 48, + 186, + 288, + 217 + ], + "type": "text", + "content": "[77] Koichiro Yamaguchi, Tamir Hazan, David McAllester, and Raquel Urtasun. Continuous markov random fields for robust stereo estimation. In ECCV, 2012. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 220, + 288, + 241 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 220, + 288, + 241 + ], + "spans": [ + { + "bbox": [ + 48, + 220, + 288, + 241 + ], + "type": "text", + "content": "[78] Yan Yan, Yuxing Mao, and Bo Li. Second: Sparsely embedded convolutional detection. Sensors, 18(10), 2018. 4" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 243, + 288, + 275 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 243, + 288, + 275 + ], + "spans": [ + { + "bbox": [ + 48, + 243, + 288, + 275 + ], + "type": "text", + "content": "[79] R. A. Yeh, C. Chen, T. Lim, A. G. Schwing, M. Hasegawa-Johnson, and M. N. Do. Semantic image inpainting with deep generative models. In CVPR, 2017. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 277, + 288, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 277, + 288, + 308 + ], + "spans": [ + { + "bbox": [ + 48, + 277, + 288, + 308 + ], + "type": "text", + "content": "[80] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Center-based 3d object detection and tracking. In CVPR, 2021. 1, 2, 3, 4, 6, 8, 9" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 310, + 288, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 310, + 288, + 342 + ], + "spans": [ + { + "bbox": [ + 48, + 310, + 288, + 342 + ], + "type": "text", + "content": "[81] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Multi-modal virtual point 3d detection. In NeurIPS, 2021. 2, 3, 6, 8" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 344, + 288, + 376 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 344, + 288, + 376 + ], + "spans": [ + { + "bbox": [ + 48, + 344, + 288, + 376 + ], + "type": "text", + "content": "[82] Wenyuan Zeng, Shenlong Wang, Renjie Liao, Yun Chen, Bin Yang, and Raquel Urtasun. Dsdnet: Deep structured self-driving network. In ECCV, 2020. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 378, + 288, + 410 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 378, + 288, + 410 + ], + "spans": [ + { + "bbox": [ + 48, + 378, + 288, + 410 + ], + "type": "text", + "content": "[83] Han Zhang, Ian Goodfellow, Dimitris Metaxas, and Augustus Odena. Self-attention generative adversarial networks. In ICML, 2019. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 412, + 288, + 456 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 412, + 288, + 456 + ], + "spans": [ + { + "bbox": [ + 48, + 412, + 288, + 456 + ], + "type": "text", + "content": "[84] Hang Zhao, Jiyang Gao, Tian Lan, Chen Sun, Benjamin Sapp, Balakrishnan Varadarajan, Yue Shen, Yi Shen, Yuning Chai, Cordelia Schmid, Congcong Li, and Dragomir Anguelov. Tnt: Target-driven trajectory prediction. In CoRL, 2020. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 457, + 288, + 489 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 457, + 288, + 489 + ], + "spans": [ + { + "bbox": [ + 48, + 457, + 288, + 489 + ], + "type": "text", + "content": "[85] Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, and Jiaya Jia. Pyramid scene parsing network. In CVPR, 2017. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 491, + 288, + 534 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 491, + 288, + 534 + ], + "spans": [ + { + "bbox": [ + 48, + 491, + 288, + 534 + ], + "type": "text", + "content": "[86] Shuai Zheng, Sadeep Jayasumana, Bernardino Romero-Paredes, Vibhav Vineet, Zhizhong Su, Dalong Du, Chang Huang, and Philip H. S. Torr. Conditional random fields as recurrent neural networks. In ICCV, 2015. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 536, + 288, + 567 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 536, + 288, + 567 + ], + "spans": [ + { + "bbox": [ + 48, + 536, + 288, + 567 + ], + "type": "text", + "content": "[87] Brady Zhou and Philipp Krahenbuhl. Cross-view transformers for real-time map-view semantic segmentation. In CVPR, 2022. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 569, + 288, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 569, + 288, + 602 + ], + "spans": [ + { + "bbox": [ + 48, + 569, + 288, + 602 + ], + "type": "text", + "content": "[88] Jun-Yan Zhu, Taesung Park, Phillip Isola, and Alexei A Efros. Unpaired image-to-image translation using cycle-consistent adversarial networks. In ICCV, 2017. 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 604, + 288, + 636 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 604, + 288, + 636 + ], + "spans": [ + { + "bbox": [ + 48, + 604, + 288, + 636 + ], + "type": "text", + "content": "[89] Song Chun Zhu, Yingnian Wu, and D. Mumford. Frame: filters, random fields, and minimax entropy towards a unified theory for texture modeling. In CVPR, 1996. 3" + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8239" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 11 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/dfdb2c34-61fe-4960-a099-a29f68122739_content_list.json b/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/dfdb2c34-61fe-4960-a099-a29f68122739_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..b72529d79611b7b38da96372b03c5ed537eb8e83 --- /dev/null +++ b/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/dfdb2c34-61fe-4960-a099-a29f68122739_content_list.json @@ -0,0 +1,1722 @@ +[ + { + "type": "text", + "text": "March in Chat: Interactive Prompting for Remote Embodied Referring Expression", + "text_level": 1, + "bbox": [ + 272, + 161, + 699, + 201 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Yanyuan Qiao $^{1}$ Yuankai Qi $^{1}$ Zheng Yu $^{1}$ Jing Liu $^{2,3}$ Qi Wu $^{1*}$", + "bbox": [ + 211, + 226, + 763, + 245 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{1}$ Australian Institute for Machine Learning, The University of Adelaide", + "bbox": [ + 206, + 245, + 764, + 261 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{2}$ Institute of Automation, Chinese Academy of Sciences", + "bbox": [ + 263, + 261, + 705, + 276 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{3}$ School of Artificial Intelligence, University of Chinese Academy of Sciences", + "bbox": [ + 184, + 276, + 798, + 293 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{yanyuan.qiao,zheng.yu,qi.wu01}@adelaide.edu.au, qykshr@gmail.com,jliu@nlpr.ia.ac.cn", + "bbox": [ + 114, + 295, + 853, + 309 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 340, + 312, + 355 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Many Vision-and-Language Navigation (VLN) tasks have been proposed in recent years, from room-based to object-based and indoor to outdoor. The REVERIE (Remote Embodied Referring Expression) is interesting since it only provides high-level instructions to the agent, which are closer to human commands in practice. Nevertheless, this poses more challenges than other VLN tasks since it requires agents to infer a navigation plan only based on a short instruction. Large Language Models (LLMs) show great potential in robot action planning by providing proper prompts. Still, this strategy has not been explored under the REVERIE settings. There are several new challenges. For example, the LLM should be environment-aware so that the navigation plan can be adjusted based on the current visual observation. Moreover, the LLM planned actions should be adaptable to the much larger and more complex REVERIE environment. This paper proposes a March-in-Chat (MiC) model that can talk to the LLM on the fly and plan dynamically based on a newly proposed Room-and-Object Aware Scene Perceiver (ROASP). Our MiC model outperforms the previous state-of-the-art by large margins by SPL and RGSPL metrics on the REVERIE benchmark. The source code is available at https://github.com/YanyuanQiao/MiC", + "bbox": [ + 75, + 371, + 473, + 690 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 77, + 719, + 208, + 733 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Vision-and-Language Navigation (VLN), which lies at the intersection of computer vision, natural language processing and robotics, has aroused great attention from research communities in the past few years. Given instructions in natural language, the VLN agent should navigate to the target location based on the dynamic observations in the 3D simulated environments. Since VLN has great", + "bbox": [ + 75, + 743, + 468, + 840 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/8f6ac22cb1ca7ce66006da99c22e278d7607c56e42a86de54ec831bc88a4072c.jpg", + "image_caption": [ + "REVERIE Instruction: Clean the small picture in front of the large mirror.", + "Figure 1: Our March-in-Chat (MiC) model is talking to a Large Language Model (LLM) to generate navigation plans on the fly, with the REVERIE instruction and the dynamic room-and-object information as inputs." + ], + "image_footnote": [], + "bbox": [ + 519, + 370, + 867, + 514 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "potential in real-world applications such as domestic assistant robots, a large amount of specific VLN tasks have been proposed, including R2R [4] and RxR [21] that ask the agent to navigate from one room to another in a photorealistic environment according to the fine-grained instruction, NDH [36] provides detailed dialogues which imply the instruction, TouchDown [7] extends the task into an outdoor environment, REVERIE [27] and SOON [39] that additionally require the agent's ability of remote object grounding and ALFRED [33] that asks the agent to interact with the target object in a single room of the synthetic environment.", + "bbox": [ + 497, + 589, + 890, + 741 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Most of these VLN tasks provide detailed step-by-step instructions to the agent, such as \"Go up the stairs and then walk the length of the couch. Walk past the dining area and into the kitchen. Stop in front of the refrigerator.\" in R2R. Although detailed instructions can help the agent better achieve the navigation goal in the simulated environments, it has a big gap towards real applications where human beings tend to give coarse-grained high-level instructions such as \"Go to the refrigerator on the second floor\".", + "bbox": [ + 497, + 741, + 892, + 866 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 129, + 49, + 200, + 85 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 253, + 48, + 789, + 86 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding author", + "bbox": [ + 95, + 853, + 220, + 866 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "15758", + "bbox": [ + 465, + 885, + 505, + 897 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Contrary to other tasks, the Remote Embodied Referring Expression (REVERIE) task is more likely to empower the real-world applications of VLN, of which the instructions are closer to those in practice, such as \"Empty the washing machine on level one\". Such high-level instruction is more challenging for VLN agents since it requires them to be more competent in perceiving the surrounding environment and the navigation progress and correspondingly making reasonable plans for the next steps.", + "bbox": [ + 75, + 125, + 468, + 251 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Recently, Large Language Models (LLMs) that internalize a wealth of commonsense knowledge show great potential in action planning for some embodied tasks with the help of suitable in-context learning. However, previous works mainly utilize LLMs to plan atomic actions of object manipulation in a very limited space with simple scenes. These predefined atomic actions can be easily planned well by the LLMs planners with a unified template. Different from these embodied tasks, REVERIE requires large-area exploration from one room to another, which is complex in the layout of rooms and scenes with diverse objects.", + "bbox": [ + 75, + 252, + 470, + 404 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this work, to adapt LLMs as the planner for REVERIE with the ability of comprehensive scene perception, we propose a novel model named March in Chat (MiC), which enables the LLM as an environment-aware instruction planner through on-the-fly dialogues between the agent and the LLM as Fig. 1 shows. Specifically, the agent is initially situated at the starting position given a high-level coarse-grained REVERIE instruction. First, a Goal-Oriented Static Planning (GOSP) module queries the LLM to point out the target object and infer where the thing may be by using the rich world knowledge internalized in the LLM. Secondly, the agent's Room-and-Object Aware Scene Perceiver (ROASP) describes the current observation and asks the LLM to generate step-by-step fine-grained planning for the next navigation steps. Then, if the ROASP finds the room has changed, the LLM is queried again by the Scene-Oriented Dynamic Planning (SODP) module to generate a new fine-grained step-by-step planning, which will be concatenated with all previous responses from the LLM. The agent will march under the guidance of such interactive prompting until the task is finished.", + "bbox": [ + 75, + 407, + 470, + 698 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To evaluate our proposed MiC, we conduct experiments on the REVERIE benchmark. Our MiC achieves a new state-of-the-art performance in all metrics on REVERIE val unseen set and REVERIE test unseen set. Mainly, MiC obtains $41.97\\%$ on the primary navigation metric of SPL and $26.17\\%$ on the major object grounding metric of RGSPL on test split, which is at least $3.09\\%$ and $3.49\\%$ higher than the previous SoTA results. We also conduct ablation studies to validate the contributions of different components in MiC and the effect of scene-aware perception in dynamic planning generation. These promising results demonstrate the effectiveness of our proposed MiC.", + "bbox": [ + 75, + 700, + 468, + 866 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In summary, we make the following contributions:", + "bbox": [ + 517, + 125, + 853, + 138 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose a novel March-in-Chat (MiC) model, which lets the REVERIE agent talk with an LLM on the fly to make plans for the next few steps.", + "- Two planning modules, namely Goal-Oriented Static Planning (GOSP) module, and Scene-Oriented Dynamic Planning (SODP) module, and one Room-and-Object Aware Scene Perceiver (ROASP) module, are proposed.", + "- Extensive quantitative and qualitative experiments are conducted on REVERIE to validate the effectiveness of our method." + ], + "bbox": [ + 517, + 138, + 890, + 292 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related work", + "text_level": 1, + "bbox": [ + 499, + 304, + 636, + 318 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Vision-and-Language Navigation Vision-and-Language Navigation (VLN) has attracted increasing attention in recent years, and many specific VLN tasks have been proposed [7, 19, 24, 27, 29, 36]. Anderson et al. [4] proposes the first VLN benchmark, Room-to-Room (R2R), which requires an agent to navigate from one room to another in a house, according to a detailed natural language step-by-step instruction in a photo-realistic environment. Later, Room-across-Room (RxR) [21] was proposed with longer and more detailed multilingual instructions. Both these two tasks give fine-grained instructions, which makes it easier to navigate to the target location. NDH [36] extends the navigation instruction to the dialogue form, and TouchDown [7] extends the environments to outdoor. REVERIE [27] and SOON [39] are proposed for remote object localization, which requires an agent not only to navigate to the target location, but also to specify the object to interact with. The difference between REVERIE and SOON is that REVERIE uses short concise instructions (e.g., \"bring me the red cup from the kitchen.\") while SOON employs long detailed instructions (e.g., \"I want to find a cylindrical, metallic and tall lamp, which is set in the bright living room. The lamp is on the cabinet which is on the left of the television and next to the window. The living room is on ...\").", + "bbox": [ + 497, + 327, + 890, + 657 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Among the aforementioned VLN tasks, the instructions of REVERIE are closer to what we would say to an intelligent domestic robot in daily life in terms of the instruction length and logic, which is usually short and concise. However, most existing methods [2, 11, 14, 16, 26, 28] are usually designed for the VLN tasks where detailed step-by-step instructions are used, thus they do not perform well on REVERIE. In this work, we specifically develop a method for REVERIE. Inspired by the fact of LLMs that implicitly internalize rich knowledge in action planning, we propose to exploit LLM as a fine-grained planner to generate detailed navigation plans from the concise instructions of REVERIE to improve navigation success.", + "bbox": [ + 497, + 659, + 890, + 838 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "LLMs as Embodied Planner Benefiting from the rise of LLMs, recent works [17, 34] have explored the use of LLMs", + "bbox": [ + 499, + 838, + 890, + 866 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "15759", + "bbox": [ + 465, + 885, + 505, + 897 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/2d287ec19b9b3dacf1b36e1f271e5271bca29e9fc29f2915cae0c7ef9fcdc46a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 522, + 138, + 537, + 148 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/2da1df1ad04dc53bc1e070729fc1fa91427a6ca4d5af948960bc2bbf0b0e3568.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 586, + 138, + 616, + 148 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/1b049502b19f12fe0ae918c8b89a5c491aa4c61228cb763ae4f1c5175ffce99e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 786, + 138, + 801, + 148 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/ddb2fd4827834db8178e14901a821a6aa28659560df8d09f7fc9cf04195e11b2.jpg", + "image_caption": [ + "REVERIE instruction: Empty the washing machine on level one.", + "Figure 2: Overview of our March-in-Chat model. The program runs along the vertical arrows from left to right, progressing with the time flow. Our model first performs Goal-Oriented Static Planning (GOSP, Sec. 4.1.1) to reason the target object and its possible lying room; then the Room-and-Object Aware Scene Perceiver (ROASP, Sec. 4.2) perceives what room type the agent currently stands in and what prominent objects can be seen; these information are used by the Scene-Oriented Dynamic Planning module (SODP, Sec. 4.1.2) to generate a detailed instruction to execute. GOSP just runs once, and we repeat ROASP and SODP until the agent chooses to stop or reaches the maximum steps." + ], + "image_footnote": [], + "bbox": [ + 90, + 150, + 873, + 318 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "in task planning for various embodied tasks. Huang et al. [17] propose to utilize the frozen LLMs (e.g., GPT-2 [31], GPT-3 [5] and Codex [8]) to plan actions for the embodied agent with in-context learning [5]. SayCan [1] translates a high-level instruction into a list of candidate low-level actions with a probability, which is then multiplied by a value function for action prediction. These two LLM planners are static, which only generate action plans at the beginning of a task. By contrast, Huang et al. [18] propose to introduce the feedback of action progress, detected objects and human assistance into the LLM planner to re-plan atomic actions. One concurrent work by Song et al. [35] injects the detected objects to re-generate high-level plans with a fixed program pattern for the ALFRED [33] task.", + "bbox": [ + 75, + 425, + 468, + 618 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "However, these above-mentioned methods mainly concentrate on planning atomic actions for object manipulation in a very limited space with simple scenes. By contrast, REVERIE has plenty of much larger and more complicated environments: 90 multi-layer buildings of various styles (e.g., office, home, gym, to name a few). To handle the complex scenarios of REVERIE, we propose a Room-and-Object Aware Scene Perceiver module that helps the LLM planner dynamically interact with the environment in the form of a natural language dialogue.", + "bbox": [ + 75, + 619, + 468, + 758 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Problem Setup", + "text_level": 1, + "bbox": [ + 77, + 771, + 226, + 788 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In the REVERIE task, given a concise and high-level instruction referring to a remote object, the agent is expected to navigate to the goal location and identify the target object in previously unseen environments. The environment is defined as an undirected graph $\\mathcal{G} = \\{\\mathcal{V},\\mathcal{E}\\}$ , where", + "bbox": [ + 75, + 796, + 468, + 866 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "$\\mathcal{V} = \\{V_i\\}_{i=1}^K$ denotes $K$ navigable nodes, and $\\mathcal{E}$ denotes connectivity edges. The agent is first placed in a starting node with the initial state $s_0$ and perceives a panorama $\\mathcal{R}_t$ as the visual observation at each time step $t$ . The panorama $\\mathcal{R}_t$ is split into $n$ single view images as $\\mathcal{R}_t = \\{r_i\\}_{i=1}^n$ . Each single view image $r_i$ is represented by an image feature vector and an orientation feature vector. In addition, the object features $\\mathcal{O}_t = \\{o_i\\}_{i=1}^m$ of $m$ objects are extracted from the panorama view using the annotated object bounding boxes or object detectors. Then, the agent makes a sequence of actions $\\langle a_0, \\ldots, a_T \\rangle$ to reach the target location, where each action is achieved by choosing a navigable node from the candidate list. The agent navigates in the environment until the target object is grounded or the agent reaches the predefined maximum trajectory length.", + "bbox": [ + 497, + 423, + 890, + 633 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4. Method", + "text_level": 1, + "bbox": [ + 499, + 647, + 589, + 660 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "As illustrated in Fig. 2, when initially situated at the starting position and given a concise high-level instruction such as \"Empty the washing machine on level one\", the agent first queries an LLM with the GOSP module (Sec. 4.1.1) to find out the target object \"washing machine\" in the instruction and reason out the potential location \"laundry room\" by using the world knowledge implied in an LLM. Then the ROASP module (Sec. 4.2) extracts the room type and visible objects from the current visual observation to obtain the environmental feedback. With the description of the scene perception, the LLM is queried again by the SODP (Sec. 4.1.2) to generate the next step instruction, which is used to guide the agent to navigate to the target object in the room. The baseline agent is based on", + "bbox": [ + 497, + 672, + 890, + 866 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "15760", + "bbox": [ + 465, + 885, + 505, + 897 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Target Object Recognition", + "text_level": 1, + "bbox": [ + 223, + 134, + 381, + 146 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Task:", + "bbox": [ + 151, + 147, + 189, + 156 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Empty the washing machine on level one.", + "bbox": [ + 151, + 157, + 426, + 168 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Goal:", + "bbox": [ + 149, + 174, + 189, + 182 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The target object is: washing machine", + "bbox": [ + 151, + 185, + 415, + 195 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Target Object Localization", + "text_level": 1, + "bbox": [ + 223, + 211, + 384, + 222 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Example:", + "bbox": [ + 146, + 222, + 205, + 233 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Question: Where does a microwave can usually appear in a house?", + "bbox": [ + 146, + 233, + 460, + 254 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Answer: kitchen.", + "bbox": [ + 146, + 255, + 260, + 264 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Question: Where does a washing machine can usually appear in a house?", + "bbox": [ + 146, + 271, + 447, + 293 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Answer: laundry room", + "bbox": [ + 146, + 294, + 292, + 304 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "(a) Prompt template of Goal-Oriented Static Planning", + "bbox": [ + 164, + 311, + 443, + 321 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Scene-Oriented Dynamic Plan", + "text_level": 1, + "bbox": [ + 559, + 133, + 739, + 144 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "At this step, I am in bedroom, I can see bed, lamp, pillow.", + "bbox": [ + 489, + 156, + 810, + 179 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Example:", + "bbox": [ + 490, + 188, + 547, + 199 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Step 1: go straight and out the room", + "bbox": [ + 490, + 200, + 747, + 211 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Step 2: pass the white table", + "bbox": [ + 490, + 211, + 690, + 220 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Step 3: move into the laundry room across the hall", + "bbox": [ + 490, + 222, + 810, + 243 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Step 4: stop at the sink", + "bbox": [ + 490, + 243, + 662, + 254 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Task: Empty the washing machine on level one. Step 1: exit the bedroom", + "bbox": [ + 489, + 264, + 808, + 287 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "(b) Prompt template of Scene-Oriented Dynamic Planning", + "bbox": [ + 494, + 311, + 796, + 321 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Figure 3: Examples of prompting templates for Goal-Oriented Static Planning (a) and Scene-Oriented Dynamic Planning (b). Outputs are marked with green color. And the red denotes the predicted object from Target Object Recognition.", + "bbox": [ + 75, + 326, + 890, + 355 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "HM3D-DUET [10], more details can be found in the supplementary material.", + "bbox": [ + 75, + 369, + 468, + 397 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Planning with World Knowledge from LLMs", + "text_level": 1, + "bbox": [ + 75, + 399, + 457, + 413 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "This section illustrates how we utilize in-context learning (ICL) [5] to acquire world knowledge from the LLMs for planning. We first briefly introduce in-context learning. Then, we elaborate the Goal-Oriented Static Planning (GOSP) and Scene-Oriented Dynamic Planning (SODP). Last, we show the demonstration selection process.", + "bbox": [ + 75, + 420, + 468, + 503 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Preliminary: In-context Learning for Planning. In-context learning (ICL) is a paradigm that lets LLMs directly make predictions based on a natural language context without gradient updates [5]. Specifically, under the setting of in-context learning, an LLM is fed a \"prompt\" that usually contains a task description and several demonstrations, and then the LLM generates the required outputs. Both the prompt template and the choice of demonstration examples have an impact on how well ICL performs. In this work, we use two different ICL settings to generate different navigation plans, i.e. the GOSP and SODP module.", + "bbox": [ + 75, + 504, + 468, + 655 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The GOSP aims to identify the target object and infer the target location by arousing the world knowledge contained in an LLM through appropriate prompts. A fixed demonstration example is used for GOSP. While the SODP aims to generate step-by-step planning instructions after observing the dynamic scenes from the environment, which is more complicated than the former. To better generate plannings, we dynamically select the most suitable demonstration examples for SODP and incorporate the environmental feedback as prompts for interactive planning.", + "bbox": [ + 75, + 657, + 468, + 795 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1.1 Goal-Oriented Static Planning (GOSP)", + "text_level": 1, + "bbox": [ + 75, + 806, + 401, + 820 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Given a high-level concise instruction, such as \"Empty the washing machine on level one\", an LLM is first asked to generate a goal-oriented static planning instruction: \"Goal:", + "bbox": [ + 75, + 824, + 468, + 866 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The target object is a washing machine. It is usually in a laundry room\", which emphasizes the target object and points out where the target object may lie. As shown in Fig. 3(a), the planning generation mainly consists of two sub-tasks: target object recognition and target object localization, which can be achieved by providing specifically designed prompts for the LLM. To this end, we design the prompts for the former sub-task in the form: \"Task: Empty the washing machine on level one. Goal: The target object is:\". Then the LLM will generate a corresponding answer: \"washing machine\". By contrast, the latter subtask, reasoning out the target location, is more complex because it requires more suitable prompts to arouse the internalized world knowledge in the LLM. To address this problem, we utilize a fixed demonstration example for the LLM, and design the prompts for the latter sub-task in the form: \"Example: Question: Where does a microwave can usually appear in a house? Answer: kitchen. Question: Where does a washing machine can usually appear in a house? Answer: \". Given such prompts, the LLM will generate the corresponding answer \"laundry room\". With these answers, we can easily combine them into the goal-oriented planning format: \"Goal: The target object is a washing machine. It is usually in a laundry room\".", + "bbox": [ + 497, + 369, + 890, + 701 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1.2 Scene-Oriented Dynamic Planning (SODP)", + "text_level": 1, + "bbox": [ + 497, + 710, + 853, + 724 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "As is shown in Fig 3(b), the prompt for SODP consists of three parts. The first part is based on the scene perception of room type, such as \"bedroom\", and visible objects, such as \"bed, lamp, pillow\", obtained by the Room-and-Object Aware Scene Perceiver (ROASP, Sec. 4.2). These information are transformed into a natural language description of the current scene in the format of \"At this step, I am in bedroom, I can see bed, lamp, pillow\". The second part is a demonstration of the fine-grained step-by-step instruction, which is selected according to the strategy", + "bbox": [ + 497, + 728, + 890, + 866 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "15761", + "bbox": [ + 465, + 887, + 502, + 897 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "R2R", + "text_level": 1, + "bbox": [ + 90, + 129, + 117, + 138 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Go up the stairs and then walk the length of the couch. Walk past the dining area and into the kitchen. Stop in front of the refrigerator.", + "bbox": [ + 90, + 138, + 442, + 159 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "FGR2R", + "text_level": 1, + "bbox": [ + 90, + 162, + 134, + 169 + ], + "page_idx": 4 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "Step 1: go up the stair", + "Step 2: and then walk the length of the couch", + "Step 3: walk past the dining area and into the kitchen", + "Step 4: stop in front of the refrigerator" + ], + "bbox": [ + 90, + 172, + 336, + 211 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Figure 4: Example of instructions in R2R and FGR2R.", + "bbox": [ + 90, + 220, + 452, + 233 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "detailed in the next section. The last part is previous instructions, such as \"Task: Empty the washing machine on level one. Step 1:\". All these three parts are concatenated together and then fed into an LLM to generate the fine-grained planning instruction for the next step accordingly, such as \"Exit the bedroom\".", + "bbox": [ + 75, + 247, + 468, + 330 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1.3 Dynamic Demonstration Selection", + "text_level": 1, + "bbox": [ + 75, + 339, + 368, + 352 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Recent works show that providing various demonstration examples to LLMs benefits the in-context learning for different tasks [17, 22, 25]. In light of these findings, to direct the LLMs in generating better fine-grained plannings, we dynamically select the most suitable demonstration example for each specific task in REVERIE as the prompt to generate the environment-aware instruction, contrary to using a single fixed demonstration for all tasks.", + "bbox": [ + 75, + 356, + 468, + 466 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Specifically, we choose the training set of the Fine-Grained R2R dataset (FGR2R) [15] as the demonstration set $\\mathcal{D}$ , of which each sample will be used as a demonstration example $D_{step}$ . As shown in Fig. 4, FGR2R decomposes each low-level instruction $I_{low}$ of R2R dataset [4] into step-by-step instructions $I_{step}$ . Then, given a high-level instruction $I_{high}$ of REVERIE, a proper $I_{low}$ will be selected as the demonstration example $D_{step}$ by a matching algorithm. In particular, we use $I_{high}$ as query $Q$ and each low-level instruction $I_{low}$ as the key $K_i$ , both of which are embedded by the Sentence-BERT [32]. The semantic distance score between the two embeddings is calculated by the cosine similarity:", + "bbox": [ + 75, + 467, + 468, + 647 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {s} (Q, K _ {i}) = \\frac {e (Q) \\cdot e (K _ {i})}{\\| e (Q) \\| \\| e (K _ {i}) \\|}, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 174, + 657, + 468, + 688 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $e(\\cdot)$ is the embedding function. If $K_{i}$ has the highest similarity score to the given query $Q$ , its corresponding step-by-step instruction $I_{step}$ will be selected as the demonstration example $D_{step}$ for the given high-level instruction $I_{high}$ .", + "bbox": [ + 75, + 697, + 468, + 767 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Room-and-Object Aware Scene Perceiver", + "text_level": 1, + "bbox": [ + 75, + 775, + 428, + 789 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Though the world knowledge acquired from the static LLMs planner could benefit the embodied task promisingly, the static LLMs planner may generate wrong or irrelevant plannings, which misleads the agent. To address this issue, the LLM planner should be aware of and interact with the", + "bbox": [ + 75, + 796, + 468, + 865 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "dynamic observations. In [35], the names of objects obtained from the ground truth or pre-trained detectors have been added to in-context prompts. However, the agents of these works act in a very limited space with simple scenes and monotonous objects. By contrast, REVERIE involves large-area exploration between different floors and rooms, where the scenes are more complex with more diverse objects. Considering these factors, we propose a room-and-object aware scene perceiver (ROASP) for the LLM planner, which predicts not only the room type but also the visible objects of the current location. Rather than using separate classifiers and detectors to individually predict each position's room types and visible object categories, we use CLIP [30] as the proposed room-and-object aware scene perceiver. Thanks to CLIP's strong ability of zero-shot image classification in the open world, the ROASP can well handle these two tasks.", + "bbox": [ + 497, + 125, + 890, + 359 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Specifically, we first fetch the room type labels from the MatterPort3D [6] semantic annotations and the object type labels are extracted from the REVERIE training dataset. They are used to build the codebook for the room categories $\\mathbf{C}_{\\mathrm{room}}$ and the object categories $\\mathbf{C}_{\\mathrm{obj}}$ , respectively. Then, at each timestep $t$ , the agent perceives the environment and obtains the panoramic visual observation $\\mathcal{R}_t = \\{r_i\\}_{i=1}^n$ . For each single-view observation $r_i$ in the panorama, the image feature $f_{\\mathrm{r}}$ is extracted by the CLIP Image Encoder", + "bbox": [ + 497, + 359, + 890, + 484 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nf _ {\\mathrm {r}} = E _ {\\mathrm {C L I P}} ^ {v} \\left(r _ {i}\\right), \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 640, + 495, + 890, + 511 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $E_{\\mathrm{CLIP}}^v (\\cdot)$ represents the CLIP Image Encoder. For each room category $c_{room}$ and each object category $c_{obj}$ , we respectively construct a text phrase of room $T_{\\mathrm{room}}$ as \"a photo of a $\\{c_{room}\\}$ \" and a text phrase of object $T_{\\mathrm{obj}}$ as \"a photo of a $\\{c_{obj}\\}$ \". Then the text feature is derived through the pretrained CLIP Text Encoder as:", + "bbox": [ + 497, + 521, + 890, + 603 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nf _ {\\text {r o o m}} = E _ {\\text {C L I P}} ^ {t} \\left(T _ {\\text {r o o m}}\\right), \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 620, + 614, + 890, + 630 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nf _ {\\mathrm {o b j}} = E _ {\\mathrm {C L I P}} ^ {t} \\left(T _ {\\mathrm {o b j}}\\right), \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 630, + 633, + 890, + 649 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $E_{\\mathrm{CLIP}}^{t}(\\cdot)$ represents the CLIP Text Encoder. At last, the similarity score $S_{\\mathrm{room}}$ between the image feature $f_{\\mathrm{r}}$ and the text feature $f_{\\mathrm{room}}$ as well as the similarity score $S_{\\mathrm{obj}}$ between the image feature $f_{\\mathrm{r}}$ and the text feature $f_{\\mathrm{obj}}$ are respectively computed as:", + "bbox": [ + 497, + 657, + 890, + 728 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nS _ {\\text {r o o m}} = \\operatorname {S o f t m a x} \\left(f _ {\\text {r o o m}} \\cdot f _ {\\mathrm {r}} ^ {T}\\right), \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 594, + 737, + 890, + 754 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nS _ {\\mathrm {o b j}} = \\operatorname {S o f t m a x} \\left(f _ {\\mathrm {o b j}} \\cdot f _ {\\mathrm {r}} ^ {T}\\right). \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 606, + 756, + 890, + 773 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Considering that the current environment normally belongs to only one type of room, though the panoramic images have multiple views, the room that the agent is currently centered in should have the largest influence on each view. Thus, we average the predicted room type scores $S_{\\mathrm{room}}$ from multiple views and choose the room type with", + "bbox": [ + 497, + 783, + 890, + 866 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "15762", + "bbox": [ + 465, + 885, + 504, + 897 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/18e1bf467aecaa44b6494c6dd77a62d55c863bf9a317af95f33cc9741a084ffe.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
HLIEmpty the washing machine on level one.
GOSPGoal: The target object is washing machine. It is usually in laundry room.
SODPStep 1: exit the bedroom\nStep 2: go down the stairs\n...
", + "bbox": [ + 87, + 130, + 457, + 218 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Figure 5: Text inputs contains three parts: High-level Instruction in REVERIE (HLI), Goal-Oriented Static Planning (GOSP) and Scene-Oriented Dynamic Planning (SODP) returned instructions.", + "bbox": [ + 75, + 225, + 468, + 281 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "the greatest score as the room type prediction $\\hat{c}_{\\mathrm{room}}$ . For object predictions, if the object occupies more proportion in a view, the matching score $S_{\\mathrm{obj}}$ should be higher. Thus, we select $k$ prominent objects with the top- $k$ matching scores as the auxiliary environment feedback in addition to the predicted room.", + "bbox": [ + 75, + 295, + 468, + 377 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. March with Interactive Prompting", + "text_level": 1, + "bbox": [ + 75, + 387, + 379, + 403 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "When the generation of the goal-oriented planning and the scene-oriented planning with perceptions from the environment is finished, the agent can march towards the target object at each timestep $t$ under the guidance of the interactive prompting. In this section, we will give a detailed description of how the interactive prompting works during the process of navigation, which mainly consists of two parts, i.e. the assembled instruction and the instruction update.", + "bbox": [ + 75, + 409, + 468, + 519 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Assembled Instruction At each timestep $t$ , the agent observes the environment and receives the assembled instructions obtained from the above-mentioned modules, and choose an action to perform. Specifically, as shown in Fig. 5, the assembled instructions $W$ of the interactive prompting mainly consist of three parts: the high-level instruction (HLI) $W_{I}$ in REVERIE, the GOSP instruction $W_{G}$ and the SODP instruction $W_{S}$ . We concatenate these three parts of instructions as the assembled instruction $W = [W_{I}, W_{G}, W_{S}]$ and use WordPieces [20] to tokenize all the words into a sequence of tokens as the textual input for the agent. Then, the agent will act under the guidance of such assembled instruction. Note that the use of the original high-level instruction $W_{I}$ can improve the model's tolerance on the noise of intermediate planning instructions.", + "bbox": [ + 75, + 527, + 468, + 733 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Instruction Update The GOSP is only conducted once at the beginning of the task. While the SODP is conducted depending on the feedback of environments. Specifically, at each timestep $t$ , if the ROASP finds the room has changed where the predicted room $\\hat{c}_{\\mathrm{room}}^t$ does not equal to $\\hat{c}_{\\mathrm{room}}^{t-1}$ , the SODP will be triggered again. Then, a new step-by-step instruction such as \"Step 2: go down the stairs\" for the next few steps will be generated by the LLM and added to the previous assembled instruction $W$ after the last step-by-step", + "bbox": [ + 75, + 741, + 468, + 866 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "instruction of \"Step 1: exit the bedroom\". Then, the agent will act under the guidance of the updated instructions $W'$ .", + "bbox": [ + 497, + 125, + 890, + 153 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Experiment", + "text_level": 1, + "bbox": [ + 499, + 167, + 623, + 182 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Evaluation Setup", + "text_level": 1, + "bbox": [ + 499, + 191, + 668, + 205 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Dataset REVERIE [27] contains 10,567 panoramic images within 90 buildings (4,140 target objects divided into 489 categories) and 21,702 instructions with 18 words on average. Each target viewpoint has 7 distinct panoramic objects with 50 bounding boxes on average. It consists of four splits: train, validation seen, validation unseen and test unseen.", + "bbox": [ + 497, + 212, + 890, + 308 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Evaluation Metrics The performance of agents is evaluated in two ways: navigation and object grounding. For the navigation sub-task, the metrics are Success Rate (SR), Oracle Success Rate (OSR), and Success weighted by Path Length [3] (SPL), where SPL is the main metric. For the grounding sub-task, the metrics are Remote Grounding Success rate (RGS) and RGS weighted by Path Length (RGSPL), where RGSPL is the main metric for this subtask. For all these metrics, higher is better.", + "bbox": [ + 497, + 320, + 890, + 442 + ], + "page_idx": 5 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "TL Trajectory Length measures the average length of all the predicted navigation trajectories in meters.", + "SR Success Rate measures the ratio of successful tasks, of which the agent's stop location is less than 3 meters away from the target location.", + "OSR Oracle Success Rate measures the ratio of tasks of which one of its trajectory viewpoints can observe the target object within 3 meters.", + "SPL Success weighted by Path Length trades-off SR (Success Rate) against TL (Trajectory Length). It measures both the accuracy and efficiency of navigation.", + "RGS Remote Grounding Success rate measures the ratio of tasks that successfully locate the target object.", + "RGSPL RGS weighted by Path Length is RGS." + ], + "bbox": [ + 499, + 441, + 890, + 661 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Implementation Details Our model is trained on a single 3090 GPU for 30,000 iterations. We set the batch size to 4 and the learning rate to $1 \\times 10^{-5}$ . The best model is selected according to performance on the validation unseen split. We use the same pretrained model and augmented data as [10] for a fair comparison. For the LLMs, we use the public GPT-2 [31] model for in-context learning. For the scene preceptor, we keep the top 3 object predictions for each position.", + "bbox": [ + 497, + 682, + 890, + 806 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.2. Comparison with State-of-The-Art Methods", + "text_level": 1, + "bbox": [ + 499, + 815, + 873, + 831 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "As shown in Table 1, we compare MiC with the state-of-the-art methods on the REVERIE benchmark. Our method", + "bbox": [ + 499, + 838, + 890, + 865 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "15763", + "bbox": [ + 465, + 885, + 504, + 897 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/49851f2a469df671cd5cdc9eaaaabec3a091afe21b35604c93a53dd24584b0f5.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodsVal UnseenTest Unseen
NavigationGroundingNavigationGrounding
TLOSR↑SR↑SPL↑RGS↑RGSPL↑TLOSR↑SR↑SPL↑RGS↑RGSPL↑
Human------21.1886.8381.5153.6677.8451.44
Seq2Seq11.078.074.202.842.161.6310.896.883.993.092.001.58
RCM [37]11.9814.239.296.974.8910.607.843.8911.686.673.673.14
SMNA [23]9.0711.288.156.444.543.619.238.395.804.533.102.39
FAST-MATTN [27]45.2828.2014.407.197.844.6739.0530.6319.8811.6111.286.08
ORIST [26]10.9025.0216.8415.148.527.5811.3829.2022.1918.9710.689.28
CKR [12]26.2631.4419.1411.8411.45-22.4630.4022.0014.2511.60-
RecBERT [16]16.7835.0230.6724.9018.7715.2715.8632.9129.6123.9916.5013.51
Airbert [13]18.7134.5127.8921.8818.2314.1817.9134.2030.2823.6116.8313.28
HAMT [9]14.0836.8432.9530.2018.9217.2813.6233.4130.4026.6714.8812.08
HOP [28]16.4636.2431.7826.1118.8515.7316.3833.0630.1724.3417.6914.34
TD-STP [38]-39.4834.8827.3221.1616.56-40.2635.8927.5119.8815.40
DUET [11]22.1151.0746.9833.7332.1523.0321.3056.9152.5136.0631.8822.06
HM3D-DUET [10]-62.1455.8940.8536.5826.76-62.3055.1738.8832.2322.68
MiC20.6462.3756.9743.6037.5228.7218.1162.4055.7441.9735.2526.17
", + "bbox": [ + 122, + 123, + 848, + 352 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/d205d02a16aad0d054092167497f3796383761f63ba0407b13a21a15f6f40f15.jpg", + "table_caption": [ + "Table 1: Comparison with the state-of-the-art methods on REVERIE." + ], + "table_footnote": [], + "table_body": "
ComponentsNavigationGrounding
OSR↑SR↑SPL↑RGS↑RGSPL↑
HLI(Baseline)58.0252.7140.4934.9326.82
HLI+GOSP59.9255.2842.4637.1328.24
HLI+SODP60.7256.2642.9436.8027.81
HLI+GOSP+SODP62.3756.9743.6037.5228.72
", + "bbox": [ + 90, + 389, + 458, + 467 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "outperforms previous methods in all metrics on both validation unseen and test unseen splits. Particularly, compared with the SoTA method HM3D-DUET [10], MiC outperforms HM3D-DUET by a large margin of $3.09\\%$ in terms of the main navigation metric SPL and $3.49\\%$ of the main object grounding metric RGSPL on the Test Unseen split. Note that MiC shares the same pre-trained model with the HM3D-DUET, these promising result demonstrates that our method can effectively improve the navigation and object grounding ability of agents.", + "bbox": [ + 75, + 503, + 468, + 642 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.3. Ablation Analysis", + "text_level": 1, + "bbox": [ + 75, + 650, + 250, + 666 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Contribution of different MiC Components In Table 2, we evaluate the effect of different components in our proposed MiC. HLI denotes only using the original high-level instruction (HLI) provided by REVERIE.", + "bbox": [ + 75, + 672, + 468, + 726 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Compared to the baseline HLI, GOSP improves the performance of both navigation $(2.57\\% \\uparrow$ on SR, $1.97\\% \\uparrow$ on SPL) and object grounding $(2.20\\% \\uparrow$ on RGS, $1.42\\% \\uparrow$ on RGSPL) with a non-trivial margin, showing the effectiveness of the proposed goal-oriented static planning. SODP further surpasses GOSP in the navigation metric $(0.98\\% \\uparrow$ on SR, $0.48\\% \\uparrow$ on SPL) while falling a little behind in the grounding metrics $(0.33\\% \\uparrow$ on RGS, $1.43\\% \\uparrow$ on RGSPL). The reason may be that the detailed step-by-step planning occupies a large proportion compared to the target object", + "bbox": [ + 75, + 728, + 468, + 866 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/a2ba68531f997a076ed6bf34c2096f4ea1fbfa5372642939d8ccd6c8ec880e63.jpg", + "table_caption": [ + "Table 2: Ablation of different components in MiC." + ], + "table_footnote": [], + "table_body": "
MethodsNavigationGrounding
OSR↑SR↑SPL↑RGS↑RGSPL↑
Baseline58.0252.7140.4934.9326.82
Static60.2455.3541.7436.3027.03
Dynamic60.7256.2642.9436.8027.81
", + "bbox": [ + 522, + 389, + 870, + 463 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/9c4826c6181c9e81b365540a6379fb9ef0796cfc6dde1224f00fcb07a2fd5b50.jpg", + "table_caption": [ + "Table 3: Comparison of different plan generation settings." + ], + "table_footnote": [], + "table_body": "
MethodsRelevancyRationality
Scene-Oriented Dynamic Planning2.061.93
- w/o Dynamic Demonstration1.411.23
- w/o ROASP1.641.55
", + "bbox": [ + 505, + 503, + 889, + 562 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 4: Human study of the prompt setting for Scene-Oriented Dynamic Planning.", + "bbox": [ + 497, + 573, + 890, + 600 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "in the input texts, which can bring the noise for object grounding while improving navigation performance. When combining all these components, the final performance gets further increased in all metrics, which surpasses the baseline with a large margin (4.26%↑ on SR, 3.11%↑ on SPL, 2.59%↑ on RGS and 1.9%↑ on RGSPL). The promising results here show that these components are complementary to each other.", + "bbox": [ + 497, + 616, + 890, + 726 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "The Effect of the ROASP To evaluate the effectiveness of ROASP used for the scene-oriented dynamic planning, we conduct another ablation study via whether incorporating the feedback from the ROASP module on REVERIE validation unseen set. We report results in three settings: (I) Baseline: The input assembled instruction only contains the given high-level instruction in REVERIE. (II) Static: The input assembled instruction contains the REVERIE and fine-grained static instructions. The difference between", + "bbox": [ + 497, + 741, + 890, + 866 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "15764", + "bbox": [ + 465, + 885, + 504, + 897 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/388916c8cba04ced0696f35036aed1758ff7903a6c11a0c3aaa5c5c89f16678c.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
REVERIE Instruction: Go to the bathroom with the two towels and empty the lower cabinet.
Scene-Oriented Dynamic Planningw/o Dynamic Demonstrationw/o ROASP
Step 1: exit the bedroomStep 1: put the towel in the bottom drawer of the toiletStep 1: exit the bathroom
Step 2: and walk into the next bedroom in the hallStep 2: walk into the kitchen
Step 3: go stand in the kitchen doorway
Step 3: go stand in the bathroomStep 4: go back to the bedroom and take the towel
Step 5: exit the bedroom
Step 6: walk into the next bedroom in the hall
REVERIE Instruction: Go to the kitchen on level 2 and open the drawer.
Scene-Oriented Dynamic Planningw/o Dynamic Demonstrationw/o ROASP
Step 1: go upstairsStep 1: open the drawer with the key in itStep 1: go upstairs and turn left at the hall
Step 2: go straight pass the couchStep 2: remove the lock from the doorStep 2: go back down the stairs
Step 3: make a slight left towards the refrigeratorStep 3: then turn onStep 3: go up the stairs again
Step 4: wait near the kitchen drawerStep 4: go back to the kitchen and open the fridge
Step 5: take out the fruit and put it in the juicer
", + "bbox": [ + 95, + 130, + 875, + 349 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Figure 6: Examples of generated instructions.", + "bbox": [ + 332, + 359, + 633, + 372 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "fine-grained static instruction and scene-oriented dynamic instruction is that static fine-grained instruction is generated without ROASP. More specifically, the query prompt for the LLM to generate step-by-step planning is fixed at each timestep, which only consists of the given high-level instruction and the selected demonstration. (III) Dynamic: The input assembled instruction contains the high-level instruction in REVERIE and scene-oriented dynamic planning instruction. As shown in Table 3, in the static setting, the performance in all metrics is improved compared to the baseline, indicating the effectiveness of the LLM's rich world knowledge in fine-grained planning. In the dynamic setting, the performance is further improved with non-trivial margins, showing the effectiveness of ROASP.", + "bbox": [ + 75, + 381, + 472, + 574 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Qualitative Analysis of Prompt Setting To further evaluate the effect of dynamic demonstration and ROASP in SODP, we perform a human evaluation about the generated plannings (see Table 4) and show the planning results (see Fig. 6). For human evaluation, we randomly selected 100 REVERIE tasks and generate fine-grained step-by-step instructions in setting of SODP, SODP without dynamic demonstration, and SODP without ROASP. We asked 10 volunteers to mark the generated step-by-step instructions in terms of their relevancy and rationality. The relevancy score ranges from 0 (unrelated) to 3 (very related), which takes into account whether the keywords in instructions are related to the REVERIE task. For example, regarding the REVERIE instruction \"Go to the kitchen and turn on the microwave\", whether there are keywords in instructions related to the kitchen scene could be rated. Rationality is rated from 0 (bad) to 3 (perfect), considering whether the instruction conforms to the logic of navigation.", + "bbox": [ + 75, + 590, + 468, + 838 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "The results are presented in Table 4. It shows that our SODP scored 2.06 on Relevancy and 1.93 on Rational-", + "bbox": [ + 75, + 838, + 468, + 866 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "ity, which could be considered acceptable since the highest score is 3 and it is challenging to generate instructions that are consistent with tasks and actual navigation logic. When removing the dynamic demonstration, the score of generated instruction drops about $31.55\\%$ on Relevancy and $36.27\\%$ on Rationality, which could also be observed in Fig. 6. Although the instruction generated without dynamic demonstration is related to the task to some extent (e.g., \"put the towel in the bottom drawer of the toilet\" has the keyword \"towel\", the instruction lacks navigation information, such as how to reach the bathroom.) As shown in the bottom example of Fig. 6, instruction without ROASP successfully guided how to go to the destination location kitchen, but it still caused confusion by going upstairs and going downstairs several times, and thus reducing the rationality score, i.e. 1.64 on Relevancy and 1.55 on Rationality. More generation results can be found in the supplementary.", + "bbox": [ + 497, + 381, + 890, + 616 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Conclusions", + "text_level": 1, + "bbox": [ + 499, + 627, + 626, + 642 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this work, we propose a novel model, March-in-Chat (MiC), for the REVEIRE task, which only provides concise high-level instructions for the VLN agent. MiC enables the REVERIE agent to talk with an LLM on the fly to generate plans for the next few steps. It consists of three main modules, Goal-Oriented Static Planning (GOSP), Scene-Oriented Dynamic Planning (SODP), and Room-and-Object Aware Scene Perceiver (ROASP) module. We conduct extensive quantitative and qualitative experiments on REVERIE and the promising results show the effectiveness of our method.", + "bbox": [ + 497, + 650, + 890, + 802 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "7. Acknowledgements", + "text_level": 1, + "bbox": [ + 499, + 815, + 675, + 831 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Jing Liu is supported by the National Key Research and Development Program of China (No. 2020AAA0106400).", + "bbox": [ + 499, + 838, + 890, + 866 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "15765", + "bbox": [ + 465, + 885, + 504, + 897 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 124, + 173, + 138 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Michael Ahn, Anthony Brohan, Noah Brown, Yevgen Chebotar, Omar Cortes, Byron David, Chelsea Finn, Chuyuan Fu, Keerthana Gopalakrishnan, Karol Hausman, Alex Herzog, Daniel Ho, Jasmine Hsu, Julian Ibarz, Brian Ichter, Alex Irpan, Eric Jang, Rosario Jauregui Ruano, Kyle Jeffrey, Sally Jesmonth, Nikhil Joshi, Ryan Julian, Dmitry Kalashnikov, Yuheng Kuang, Kuang-Huei Lee, Sergey Levine, Yao Lu, Linda Luu, Carolina Parada, Peter Pastor, Jornell Quiambao, Kanishka Rao, Jarek Rettinghouse, Diego Reyes, Pierre Sermanet, Nicolas Sievers, Clayton Tan, Alexander Toshev, Vincent Vanhoucke, Fei Xia, Ted Xiao, Peng Xu, Sichun Xu, Mengyuan Yan, and Andy Zeng. Do as i can and not as i say: Grounding language in robotic affordances. In arXiv preprint arXiv:2204.01691, 2022. 3", + "[2] Dong An, Yuankai Qi, Yangguang Li, Yan Huang, Liang Wang, Tieniu Tan, and Jing Shao. Bevbert: Topo-metric map pre-training for language-guided navigation. arXiv preprint arXiv:2212.04385, 2022. 2", + "[3] Peter Anderson, Angel X. Chang, Devendra Singh Chaplot, Alexey Dosovitskiy, Saurabh Gupta, Vladlen Koltun, Jana Kosecka, Jitendra Malik, Roozbeh Mottaghi, Manolis Savva, and Amir Roshan Zamir. On evaluation of embodied navigation agents. CoRR, abs/1807.06757, 2018. 6", + "[4] Peter Anderson, Qi Wu, Damien Teney, Jake Bruce, Mark Johnson, Niko Sünderhauf, Ian D. Reid, Stephen Gould, and Anton van den Hengel. Vision-and-language navigation: Interpreting visually-grounded navigation instructions in real environments. In CVPR, pages 3674-3683, 2018. 1, 2, 5", + "[5] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, Sandhini Agarwal, Ariel Herbert-Voss, Gretchen Krueger, Tom Henighan, Rewon Child, Aditya Ramesh, Daniel Ziegler, Jeffrey Wu, Clemens Winter, Chris Hesse, Mark Chen, Eric Sigler, Mateusz Litwin, Scott Gray, Benjamin Chess, Jack Clark, Christopher Berner, Sam McCandlish, Alec Radford, Ilya Sutskever, and Dario Amodei. Language models are few-shot learners. In NeurIPS, pages 1877-1901, 2020. 3, 4", + "[6] Angel X. Chang, Angela Dai, Thomas A. Funkhouser, Macej Halber, Matthias Nießner, Manolis Savva, Shuran Song, Andy Zeng, and Yinda Zhang. Matterport3d: Learning from RGB-D data in indoor environments. In 3DV, pages 667-676, 2017. 5", + "[7] Howard Chen, Alane Suhr, Dipendra Misra, Noah Snavely, and Yoav Artzi. TOUCHDOWN: natural language navigation and spatial reasoning in visual street environments. In CVPR, pages 12538-12547, 2019. 1, 2", + "[8] Mark Chen, Jerry Tworek, Heewoo Jun, Qiming Yuan, Henrique Ponde de Oliveira Pinto, Jared Kaplan, Harri Edwards, Yuri Burda, Nicholas Joseph, Greg Brockman, et al. Evaluating large language models trained on code. arXiv preprint arXiv:2107.03374, 2021. 3", + "[9] Shizhe Chen, Pierre-Louis Guhur, Cordelia Schmid, and Ivan Laptev. History aware multimodal transformer for vision-and-language navigation. In NeurIPS, pages 5834-5847, 2021. 7" + ], + "bbox": [ + 85, + 147, + 468, + 865 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[10] Shizhe Chen, Pierre-Louis Guhur, Makarand Tapaswi, Cordelia Schmid, and Ivan Laptev. Learning from unlabeled 3d environments for vision-and-language navigation. In ECCV, 2022. 4, 6, 7", + "[11] Shizhe Chen, Pierre-Louis Guhur, Makarand Tapaswi, Cordelia Schmid, and Ivan Laptev. Think global, act local: Dual-scale graph transformer for vision-and-language navigation. In CVPR, 2022. 2, 7", + "[12] Chen Gao, Jinyu Chen, Si Liu, Luting Wang, Qiong Zhang, and Qi Wu. Room-and-object aware knowledge reasoning for remote embodied referring expression. In CVPR, pages 3064-3073, 2021. 7", + "[13] Pierre-Louis Guhur, Makarand Tapaswi, Shizhe Chen, Ivan Laptev, and Cordelia Schmid. Airbert: In-domain pretraining for vision-and-language navigation. In ICCV, pages 1634-1643, 2021. 7", + "[14] Keji He, Yan Huang, Qi Wu, Jianhua Yang, Dong An, Shuanglin Sima, and Liang Wang. Landmark-rxr: Solving vision-and-language navigation with fine-grained alignment supervision. NeurIPS, 34:652-663, 2021. 2", + "[15] Yicong Hong, Cristian Rodriguez Opazo, Qi Wu, and Stephen Gould. Sub-instruction aware vision-and-language navigation. In Bonnie Webber, Trevor Cohn, Yulan He, and Yang Liu, editors, EMNLP, pages 3360-3376, 2020. 5", + "[16] Yicong Hong, Qi Wu, Yuankai Qi, Cristian Rodriguez Opazo, and Stephen Gould. VLN $\\text{©}$ BERT: A recurrent vision-and-language BERT for navigation. In CVPR, pages 1643-1653, 2021. 2, 7", + "[17] Wenlong Huang, Pieter Abbeel, Deepak Pathak, and Igor Mordatch. Language models as zero-shot planners: Extracting actionable knowledge for embodied agents. In ICML, pages 9118-9147. PMLR, 2022. 2, 3, 5", + "[18] Wenlong Huang, Fei Xia, Ted Xiao, Harris Chan, Jacky Liang, Pete Florence, Andy Zeng, Jonathan Tompson, Igor Mordatch, Yevgen Chebotar, Pierre Sermanet, Noah Brown, Tomas Jackson, Linda Luu, Sergey Levine, Karol Hausman, and Brian Ichter. Inner monologue: Embodied reasoning through planning with language models. In arXiv preprint arXiv:2207.05608, 2022. 3", + "[19] Vihan Jain, Gabriel Magalhães, Alexander Ku, Ashish Vaswani, Eugene Ie, and Jason Baldridge. Stay on the path: Instruction fidelity in vision-and-language navigation. pages 1862-1872, 2019. 2", + "[20] Melvin Johnson, Mike Schuster, Quoc V. Le, Maxim Krikun, Yonghui Wu, Zhifeng Chen, Nikhil Thorat, Fernanda B. Viégas, Martin Wattenberg, Greg Corrado, Macduff Hughes, and Jeffrey Dean. Google's multilingual neural machine translation system: Enabling zero-shot translation. Trans. Assoc. Comput. Linguistics, 5:339-351, 2017. 6", + "[21] Alexander Ku, Peter Anderson, Roma Patel, Eugene Ie, and Jason Baldridge. Room-across-room: Multilingual vision-and-language navigation with dense spatiotemporal grounding. In EMNLP, pages 4392-4412, 2020. 1, 2", + "[22] Jiachang Liu, Dinghan Shen, Yizhe Zhang, Bill Dolan, Lawrence Carin, and Weizhu Chen. What makes good in-context examples for gpt-3? arXiv preprint arXiv:2101.06804, 2021. 5" + ], + "bbox": [ + 502, + 127, + 890, + 865 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "15766", + "bbox": [ + 465, + 887, + 504, + 897 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[23] Chih-Yao Ma, Jiasen Lu, Zuxuan Wu, Ghassan AlRegib, Zsolt Kira, Richard Socher, and Caiming Xiong. Self-monitoring navigation agent via auxiliary progress estimation. In ICLR, 2019. 7", + "[24] Khanh Nguyen and Hal Daumé III. Help, anna! visual navigation with natural multimodal assistance via retrospective curiosity-encouraging imitation learning. pages 684–695. Association for Computational Linguistics, 2019. 2", + "[25] Gabriel Poesia, Alex Polozov, Vu Le, Ashish Tiwari, Gustavo Soares, Christopher Meek, and Sumit Gulwani. Synchromesh: Reliable code generation from pre-trained language models. In ICLR, 2022. 5", + "[26] Yuankai Qi, Zizheng Pan, Yicong Hong, Ming-Hsuan Yang, Anton van den Hengel, and Qi Wu. The road to knowwhere: An object-and-room informed sequential bert for indoor vision-language navigation. In ICCV, pages 1655-1664, 2021. 2, 7", + "[27] Yuankai Qi, Qi Wu, Peter Anderson, Xin Wang, William Yang Wang, Chunhua Shen, and Anton van den Hengel. REVERIE: remote embodied visual referring expression in real indoor environments. In CVPR, pages 9979-9988, 2020. 1, 2, 6, 7", + "[28] Yanyuan Qiao, Yuankai Qi, Yicong Hong, Zheng Yu, Peng Wang, and Qi Wu. HOP: history-and-order aware pretraining for vision-and-language navigation. In CVPR, pages 15397-15406, 2022. 2, 7", + "[29] Yanyuan Qiao, Yuankai Qi, Yicong Hong, Zheng Yu, Peng Wang, and Qi Wu. Hop+: History-enhanced and order-aware pre-training for vision-and-language navigation. IEEE TPAMI, 2023. 2", + "[30] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, Gretchen Krueger, and Ilya Sutskever. Learning transferable visual models from natural language supervision. In ICML, volume 139, pages 8748-8763, 2021. 5", + "[31] Alec Radford, Jeffrey Wu, Rewon Child, David Luan, Dario Amodei, Ilya Sutskever, et al. Language models are unsupervised multitask learners. OpenAI blog, 1(8):9, 2019. 3, 6", + "[32] Nils Reimers and Iryna Gurevych. Sentence-bert: Sentence embeddings using siamese bert-networks. In Kentaro Inui, Jing Jiang, Vincent Ng, and Xiaojun Wan, editors, EMNLP-IJCNLP, pages 3980-3990, 2019. 5", + "[33] Mohit Shridhar, Jesse Thomason, Daniel Gordon, Yonatan Bisk, Winson Han, Roozbeh Mottaghi, Luke Zettlemoyer, and Dieter Fox. ALFRED: A benchmark for interpreting grounded instructions for everyday tasks. In CVPR, pages 10737-10746, 2020. 1, 3", + "[34] Ishika Singh, Valts Blukis, Arsalan Mousavian, Ankit Goyal, Danfei Xu, Jonathan Tremblay, Dieter Fox, Jesse Thomason, and Animesh Garg. ProgPrompt: Generating situated robot task plans using large language models. 2022. 2", + "[35] Chan Hee Song, Jiaman Wu, Clayton Washington, Brian M Sadler, Wei-Lun Chao, and Yu Su. Llm-planner: Few-shot grounded planning for embodied agents with large language models. arXiv preprint arXiv:2212.04088, 2022. 3, 5" + ], + "bbox": [ + 78, + 125, + 468, + 866 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[36] Jesse Thomason, Michael Murray, Maya Cakmak, and Luke Zettlemoyer. Vision-and-dialog navigation. In CoRL, pages 394-406, 2019. 1, 2", + "[37] Xin Wang, Qiuyuan Huang, Asli Celikyilmaz, Jianfeng Gao, Dinghan Shen, Yuan-Fang Wang, William Yang Wang, and Lei Zhang. Reinforced cross-modal matching and self-supervised imitation learning for vision-language navigation. In CVPR, pages 6629-6638, 2019. 7", + "[38] Yusheng Zhao, Jinyu Chen, Chen Gao, Wenguan Wang, Lirong Yang, Haibing Ren, Huaxia Xia, and Si Liu. Target-driven structured transformer planner for vision-language navigation. pages 4194-4203, 2022. 7", + "[39] Fengda Zhu, Xiwen Liang, Yi Zhu, Qizhi Yu, Xiaojun Chang, and Xiaodan Liang. SOON: scenario oriented object navigation with graph-based exploration. In CVPR, pages 12689-12699, 2021. 1, 2" + ], + "bbox": [ + 502, + 125, + 890, + 332 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "15767", + "bbox": [ + 465, + 885, + 504, + 897 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/dfdb2c34-61fe-4960-a099-a29f68122739_model.json b/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/dfdb2c34-61fe-4960-a099-a29f68122739_model.json new file mode 100644 index 0000000000000000000000000000000000000000..1fbc8a5b3340e18648c02443524685ad96859b5c --- /dev/null +++ b/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/dfdb2c34-61fe-4960-a099-a29f68122739_model.json @@ -0,0 +1,2255 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.13, + 0.051, + 0.201, + 0.086 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.254, + 0.049, + 0.79, + 0.087 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.273, + 0.162, + 0.7, + 0.203 + ], + "angle": 0, + "content": "March in Chat: Interactive Prompting for Remote Embodied Referring Expression" + }, + { + "type": "text", + "bbox": [ + 0.212, + 0.228, + 0.764, + 0.246 + ], + "angle": 0, + "content": "Yanyuan Qiao\\(^{1}\\) Yuankai Qi\\(^{1}\\) Zheng Yu\\(^{1}\\) Jing Liu\\(^{2,3}\\) Qi Wu\\(^{1*}\\)" + }, + { + "type": "text", + "bbox": [ + 0.207, + 0.246, + 0.765, + 0.262 + ], + "angle": 0, + "content": "\\(^{1}\\)Australian Institute for Machine Learning, The University of Adelaide" + }, + { + "type": "text", + "bbox": [ + 0.264, + 0.262, + 0.706, + 0.277 + ], + "angle": 0, + "content": "\\(^{2}\\)Institute of Automation, Chinese Academy of Sciences" + }, + { + "type": "text", + "bbox": [ + 0.185, + 0.277, + 0.799, + 0.294 + ], + "angle": 0, + "content": "\\(^{3}\\)School of Artificial Intelligence, University of Chinese Academy of Sciences" + }, + { + "type": "text", + "bbox": [ + 0.115, + 0.296, + 0.855, + 0.31 + ], + "angle": 0, + "content": "{yanyuan.qiao,zheng.yu,qi.wu01}@adelaide.edu.au, qykshr@gmail.com,jliu@nlpr.ia.ac.cn" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.342, + 0.314, + 0.356 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.372, + 0.474, + 0.691 + ], + "angle": 0, + "content": "Many Vision-and-Language Navigation (VLN) tasks have been proposed in recent years, from room-based to object-based and indoor to outdoor. The REVERIE (Remote Embodied Referring Expression) is interesting since it only provides high-level instructions to the agent, which are closer to human commands in practice. Nevertheless, this poses more challenges than other VLN tasks since it requires agents to infer a navigation plan only based on a short instruction. Large Language Models (LLMs) show great potential in robot action planning by providing proper prompts. Still, this strategy has not been explored under the REVERIE settings. There are several new challenges. For example, the LLM should be environment-aware so that the navigation plan can be adjusted based on the current visual observation. Moreover, the LLM planned actions should be adaptable to the much larger and more complex REVERIE environment. This paper proposes a March-in-Chat (MiC) model that can talk to the LLM on the fly and plan dynamically based on a newly proposed Room-and-Object Aware Scene Perceiver (ROASP). Our MiC model outperforms the previous state-of-the-art by large margins by SPL and RGSPL metrics on the REVERIE benchmark. The source code is available at https://github.com/YanyuanQiao/MiC" + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.72, + 0.21, + 0.734 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.744, + 0.47, + 0.842 + ], + "angle": 0, + "content": "Vision-and-Language Navigation (VLN), which lies at the intersection of computer vision, natural language processing and robotics, has aroused great attention from research communities in the past few years. Given instructions in natural language, the VLN agent should navigate to the target location based on the dynamic observations in the 3D simulated environments. Since VLN has great" + }, + { + "type": "image_caption", + "bbox": [ + 0.513, + 0.346, + 0.868, + 0.369 + ], + "angle": 0, + "content": "REVERIE Instruction: Clean the small picture in front of the large mirror." + }, + { + "type": "image", + "bbox": [ + 0.52, + 0.371, + 0.868, + 0.515 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.526, + 0.893, + 0.582 + ], + "angle": 0, + "content": "Figure 1: Our March-in-Chat (MiC) model is talking to a Large Language Model (LLM) to generate navigation plans on the fly, with the REVERIE instruction and the dynamic room-and-object information as inputs." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.59, + 0.892, + 0.742 + ], + "angle": 0, + "content": "potential in real-world applications such as domestic assistant robots, a large amount of specific VLN tasks have been proposed, including R2R [4] and RxR [21] that ask the agent to navigate from one room to another in a photorealistic environment according to the fine-grained instruction, NDH [36] provides detailed dialogues which imply the instruction, TouchDown [7] extends the task into an outdoor environment, REVERIE [27] and SOON [39] that additionally require the agent's ability of remote object grounding and ALFRED [33] that asks the agent to interact with the target object in a single room of the synthetic environment." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.742, + 0.893, + 0.867 + ], + "angle": 0, + "content": "Most of these VLN tasks provide detailed step-by-step instructions to the agent, such as \"Go up the stairs and then walk the length of the couch. Walk past the dining area and into the kitchen. Stop in front of the refrigerator.\" in R2R. Although detailed instructions can help the agent better achieve the navigation goal in the simulated environments, it has a big gap towards real applications where human beings tend to give coarse-grained high-level instructions such as \"Go to the refrigerator on the second floor\"." + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.854, + 0.221, + 0.867 + ], + "angle": 0, + "content": "*Corresponding author" + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.887, + 0.506, + 0.898 + ], + "angle": 0, + "content": "15758" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.126, + 0.47, + 0.252 + ], + "angle": 0, + "content": "Contrary to other tasks, the Remote Embodied Referring Expression (REVERIE) task is more likely to empower the real-world applications of VLN, of which the instructions are closer to those in practice, such as \"Empty the washing machine on level one\". Such high-level instruction is more challenging for VLN agents since it requires them to be more competent in perceiving the surrounding environment and the navigation progress and correspondingly making reasonable plans for the next steps." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.253, + 0.471, + 0.406 + ], + "angle": 0, + "content": "Recently, Large Language Models (LLMs) that internalize a wealth of commonsense knowledge show great potential in action planning for some embodied tasks with the help of suitable in-context learning. However, previous works mainly utilize LLMs to plan atomic actions of object manipulation in a very limited space with simple scenes. These predefined atomic actions can be easily planned well by the LLMs planners with a unified template. Different from these embodied tasks, REVERIE requires large-area exploration from one room to another, which is complex in the layout of rooms and scenes with diverse objects." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.408, + 0.471, + 0.699 + ], + "angle": 0, + "content": "In this work, to adapt LLMs as the planner for REVERIE with the ability of comprehensive scene perception, we propose a novel model named March in Chat (MiC), which enables the LLM as an environment-aware instruction planner through on-the-fly dialogues between the agent and the LLM as Fig. 1 shows. Specifically, the agent is initially situated at the starting position given a high-level coarse-grained REVERIE instruction. First, a Goal-Oriented Static Planning (GOSP) module queries the LLM to point out the target object and infer where the thing may be by using the rich world knowledge internalized in the LLM. Secondly, the agent's Room-and-Object Aware Scene Perceiver (ROASP) describes the current observation and asks the LLM to generate step-by-step fine-grained planning for the next navigation steps. Then, if the ROASP finds the room has changed, the LLM is queried again by the Scene-Oriented Dynamic Planning (SODP) module to generate a new fine-grained step-by-step planning, which will be concatenated with all previous responses from the LLM. The agent will march under the guidance of such interactive prompting until the task is finished." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.701, + 0.47, + 0.868 + ], + "angle": 0, + "content": "To evaluate our proposed MiC, we conduct experiments on the REVERIE benchmark. Our MiC achieves a new state-of-the-art performance in all metrics on REVERIE val unseen set and REVERIE test unseen set. Mainly, MiC obtains \\(41.97\\%\\) on the primary navigation metric of SPL and \\(26.17\\%\\) on the major object grounding metric of RGSPL on test split, which is at least \\(3.09\\%\\) and \\(3.49\\%\\) higher than the previous SoTA results. We also conduct ablation studies to validate the contributions of different components in MiC and the effect of scene-aware perception in dynamic planning generation. These promising results demonstrate the effectiveness of our proposed MiC." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.127, + 0.854, + 0.139 + ], + "angle": 0, + "content": "In summary, we make the following contributions:" + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.14, + 0.891, + 0.181 + ], + "angle": 0, + "content": "- We propose a novel March-in-Chat (MiC) model, which lets the REVERIE agent talk with an LLM on the fly to make plans for the next few steps." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.183, + 0.892, + 0.252 + ], + "angle": 0, + "content": "- Two planning modules, namely Goal-Oriented Static Planning (GOSP) module, and Scene-Oriented Dynamic Planning (SODP) module, and one Room-and-Object Aware Scene Perceiver (ROASP) module, are proposed." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.253, + 0.891, + 0.293 + ], + "angle": 0, + "content": "- Extensive quantitative and qualitative experiments are conducted on REVERIE to validate the effectiveness of our method." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.14, + 0.892, + 0.293 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.305, + 0.637, + 0.319 + ], + "angle": 0, + "content": "2. Related work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.328, + 0.892, + 0.659 + ], + "angle": 0, + "content": "Vision-and-Language Navigation Vision-and-Language Navigation (VLN) has attracted increasing attention in recent years, and many specific VLN tasks have been proposed [7, 19, 24, 27, 29, 36]. Anderson et al. [4] proposes the first VLN benchmark, Room-to-Room (R2R), which requires an agent to navigate from one room to another in a house, according to a detailed natural language step-by-step instruction in a photo-realistic environment. Later, Room-across-Room (RxR) [21] was proposed with longer and more detailed multilingual instructions. Both these two tasks give fine-grained instructions, which makes it easier to navigate to the target location. NDH [36] extends the navigation instruction to the dialogue form, and TouchDown [7] extends the environments to outdoor. REVERIE [27] and SOON [39] are proposed for remote object localization, which requires an agent not only to navigate to the target location, but also to specify the object to interact with. The difference between REVERIE and SOON is that REVERIE uses short concise instructions (e.g., \"bring me the red cup from the kitchen.\") while SOON employs long detailed instructions (e.g., \"I want to find a cylindrical, metallic and tall lamp, which is set in the bright living room. The lamp is on the cabinet which is on the left of the television and next to the window. The living room is on ...\")." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.66, + 0.892, + 0.839 + ], + "angle": 0, + "content": "Among the aforementioned VLN tasks, the instructions of REVERIE are closer to what we would say to an intelligent domestic robot in daily life in terms of the instruction length and logic, which is usually short and concise. However, most existing methods [2, 11, 14, 16, 26, 28] are usually designed for the VLN tasks where detailed step-by-step instructions are used, thus they do not perform well on REVERIE. In this work, we specifically develop a method for REVERIE. Inspired by the fact of LLMs that implicitly internalize rich knowledge in action planning, we propose to exploit LLM as a fine-grained planner to generate detailed navigation plans from the concise instructions of REVERIE to improve navigation success." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.839, + 0.892, + 0.867 + ], + "angle": 0, + "content": "LLMs as Embodied Planner Benefiting from the rise of LLMs, recent works [17, 34] have explored the use of LLMs" + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.887, + 0.506, + 0.898 + ], + "angle": 0, + "content": "15759" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.092, + 0.135, + 0.466, + 0.148 + ], + "angle": 0, + "content": "REVERIE instruction: Empty the washing machine on level one." + }, + { + "type": "image", + "bbox": [ + 0.524, + 0.14, + 0.539, + 0.149 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.587, + 0.14, + 0.617, + 0.149 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.787, + 0.14, + 0.803, + 0.149 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.092, + 0.151, + 0.874, + 0.319 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.329, + 0.893, + 0.414 + ], + "angle": 0, + "content": "Figure 2: Overview of our March-in-Chat model. The program runs along the vertical arrows from left to right, progressing with the time flow. Our model first performs Goal-Oriented Static Planning (GOSP, Sec. 4.1.1) to reason the target object and its possible lying room; then the Room-and-Object Aware Scene Perceiver (ROASP, Sec. 4.2) perceives what room type the agent currently stands in and what prominent objects can be seen; these information are used by the Scene-Oriented Dynamic Planning module (SODP, Sec. 4.1.2) to generate a detailed instruction to execute. GOSP just runs once, and we repeat ROASP and SODP until the agent chooses to stop or reaches the maximum steps." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.426, + 0.47, + 0.619 + ], + "angle": 0, + "content": "in task planning for various embodied tasks. Huang et al. [17] propose to utilize the frozen LLMs (e.g., GPT-2 [31], GPT-3 [5] and Codex [8]) to plan actions for the embodied agent with in-context learning [5]. SayCan [1] translates a high-level instruction into a list of candidate low-level actions with a probability, which is then multiplied by a value function for action prediction. These two LLM planners are static, which only generate action plans at the beginning of a task. By contrast, Huang et al. [18] propose to introduce the feedback of action progress, detected objects and human assistance into the LLM planner to re-plan atomic actions. One concurrent work by Song et al. [35] injects the detected objects to re-generate high-level plans with a fixed program pattern for the ALFRED [33] task." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.62, + 0.47, + 0.759 + ], + "angle": 0, + "content": "However, these above-mentioned methods mainly concentrate on planning atomic actions for object manipulation in a very limited space with simple scenes. By contrast, REVERIE has plenty of much larger and more complicated environments: 90 multi-layer buildings of various styles (e.g., office, home, gym, to name a few). To handle the complex scenarios of REVERIE, we propose a Room-and-Object Aware Scene Perceiver module that helps the LLM planner dynamically interact with the environment in the form of a natural language dialogue." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.773, + 0.227, + 0.789 + ], + "angle": 0, + "content": "3. Problem Setup" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.797, + 0.469, + 0.868 + ], + "angle": 0, + "content": "In the REVERIE task, given a concise and high-level instruction referring to a remote object, the agent is expected to navigate to the goal location and identify the target object in previously unseen environments. The environment is defined as an undirected graph \\(\\mathcal{G} = \\{\\mathcal{V},\\mathcal{E}\\}\\), where" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.425, + 0.892, + 0.634 + ], + "angle": 0, + "content": "\\(\\mathcal{V} = \\{V_i\\}_{i=1}^K\\) denotes \\(K\\) navigable nodes, and \\(\\mathcal{E}\\) denotes connectivity edges. The agent is first placed in a starting node with the initial state \\(s_0\\) and perceives a panorama \\(\\mathcal{R}_t\\) as the visual observation at each time step \\(t\\). The panorama \\(\\mathcal{R}_t\\) is split into \\(n\\) single view images as \\(\\mathcal{R}_t = \\{r_i\\}_{i=1}^n\\). Each single view image \\(r_i\\) is represented by an image feature vector and an orientation feature vector. In addition, the object features \\(\\mathcal{O}_t = \\{o_i\\}_{i=1}^m\\) of \\(m\\) objects are extracted from the panorama view using the annotated object bounding boxes or object detectors. Then, the agent makes a sequence of actions \\(\\langle a_0, \\ldots, a_T \\rangle\\) to reach the target location, where each action is achieved by choosing a navigable node from the candidate list. The agent navigates in the environment until the target object is grounded or the agent reaches the predefined maximum trajectory length." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.648, + 0.59, + 0.661 + ], + "angle": 0, + "content": "4. Method" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.673, + 0.892, + 0.868 + ], + "angle": 0, + "content": "As illustrated in Fig. 2, when initially situated at the starting position and given a concise high-level instruction such as \"Empty the washing machine on level one\", the agent first queries an LLM with the GOSP module (Sec. 4.1.1) to find out the target object \"washing machine\" in the instruction and reason out the potential location \"laundry room\" by using the world knowledge implied in an LLM. Then the ROASP module (Sec. 4.2) extracts the room type and visible objects from the current visual observation to obtain the environmental feedback. With the description of the scene perception, the LLM is queried again by the SODP (Sec. 4.1.2) to generate the next step instruction, which is used to guide the agent to navigate to the target object in the room. The baseline agent is based on" + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.887, + 0.506, + 0.898 + ], + "angle": 0, + "content": "15760" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.225, + 0.135, + 0.383, + 0.147 + ], + "angle": 0, + "content": "Target Object Recognition" + }, + { + "type": "text", + "bbox": [ + 0.152, + 0.148, + 0.19, + 0.157 + ], + "angle": 0, + "content": "Task:" + }, + { + "type": "text", + "bbox": [ + 0.152, + 0.158, + 0.428, + 0.169 + ], + "angle": 0, + "content": "Empty the washing machine on level one." + }, + { + "type": "text", + "bbox": [ + 0.151, + 0.175, + 0.19, + 0.184 + ], + "angle": 0, + "content": "Goal:" + }, + { + "type": "text", + "bbox": [ + 0.152, + 0.186, + 0.416, + 0.197 + ], + "angle": 0, + "content": "The target object is: washing machine" + }, + { + "type": "title", + "bbox": [ + 0.225, + 0.212, + 0.385, + 0.223 + ], + "angle": 0, + "content": "Target Object Localization" + }, + { + "type": "text", + "bbox": [ + 0.147, + 0.223, + 0.206, + 0.234 + ], + "angle": 0, + "content": "Example:" + }, + { + "type": "text", + "bbox": [ + 0.147, + 0.235, + 0.462, + 0.255 + ], + "angle": 0, + "content": "Question: Where does a microwave can usually appear in a house?" + }, + { + "type": "text", + "bbox": [ + 0.147, + 0.256, + 0.262, + 0.266 + ], + "angle": 0, + "content": "Answer: kitchen." + }, + { + "type": "text", + "bbox": [ + 0.147, + 0.272, + 0.448, + 0.294 + ], + "angle": 0, + "content": "Question: Where does a washing machine can usually appear in a house?" + }, + { + "type": "text", + "bbox": [ + 0.147, + 0.295, + 0.293, + 0.305 + ], + "angle": 0, + "content": "Answer: laundry room" + }, + { + "type": "text", + "bbox": [ + 0.165, + 0.312, + 0.444, + 0.323 + ], + "angle": 0, + "content": "(a) Prompt template of Goal-Oriented Static Planning" + }, + { + "type": "title", + "bbox": [ + 0.56, + 0.134, + 0.741, + 0.146 + ], + "angle": 0, + "content": "Scene-Oriented Dynamic Plan" + }, + { + "type": "text", + "bbox": [ + 0.49, + 0.157, + 0.811, + 0.18 + ], + "angle": 0, + "content": "At this step, I am in bedroom, I can see bed, lamp, pillow." + }, + { + "type": "text", + "bbox": [ + 0.491, + 0.19, + 0.548, + 0.2 + ], + "angle": 0, + "content": "Example:" + }, + { + "type": "text", + "bbox": [ + 0.491, + 0.201, + 0.748, + 0.212 + ], + "angle": 0, + "content": "Step 1: go straight and out the room" + }, + { + "type": "text", + "bbox": [ + 0.491, + 0.212, + 0.692, + 0.222 + ], + "angle": 0, + "content": "Step 2: pass the white table" + }, + { + "type": "text", + "bbox": [ + 0.491, + 0.223, + 0.811, + 0.244 + ], + "angle": 0, + "content": "Step 3: move into the laundry room across the hall" + }, + { + "type": "text", + "bbox": [ + 0.491, + 0.244, + 0.663, + 0.255 + ], + "angle": 0, + "content": "Step 4: stop at the sink" + }, + { + "type": "text", + "bbox": [ + 0.49, + 0.266, + 0.81, + 0.288 + ], + "angle": 0, + "content": "Task: Empty the washing machine on level one. Step 1: exit the bedroom" + }, + { + "type": "text", + "bbox": [ + 0.495, + 0.312, + 0.798, + 0.323 + ], + "angle": 0, + "content": "(b) Prompt template of Scene-Oriented Dynamic Planning" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.327, + 0.892, + 0.356 + ], + "angle": 0, + "content": "Figure 3: Examples of prompting templates for Goal-Oriented Static Planning (a) and Scene-Oriented Dynamic Planning (b). Outputs are marked with green color. And the red denotes the predicted object from Target Object Recognition." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.37, + 0.469, + 0.398 + ], + "angle": 0, + "content": "HM3D-DUET [10], more details can be found in the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.4, + 0.458, + 0.414 + ], + "angle": 0, + "content": "4.1. Planning with World Knowledge from LLMs" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.421, + 0.469, + 0.504 + ], + "angle": 0, + "content": "This section illustrates how we utilize in-context learning (ICL) [5] to acquire world knowledge from the LLMs for planning. We first briefly introduce in-context learning. Then, we elaborate the Goal-Oriented Static Planning (GOSP) and Scene-Oriented Dynamic Planning (SODP). Last, we show the demonstration selection process." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.505, + 0.469, + 0.656 + ], + "angle": 0, + "content": "Preliminary: In-context Learning for Planning. In-context learning (ICL) is a paradigm that lets LLMs directly make predictions based on a natural language context without gradient updates [5]. Specifically, under the setting of in-context learning, an LLM is fed a \"prompt\" that usually contains a task description and several demonstrations, and then the LLM generates the required outputs. Both the prompt template and the choice of demonstration examples have an impact on how well ICL performs. In this work, we use two different ICL settings to generate different navigation plans, i.e. the GOSP and SODP module." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.658, + 0.469, + 0.796 + ], + "angle": 0, + "content": "The GOSP aims to identify the target object and infer the target location by arousing the world knowledge contained in an LLM through appropriate prompts. A fixed demonstration example is used for GOSP. While the SODP aims to generate step-by-step planning instructions after observing the dynamic scenes from the environment, which is more complicated than the former. To better generate plannings, we dynamically select the most suitable demonstration examples for SODP and incorporate the environmental feedback as prompts for interactive planning." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.807, + 0.403, + 0.821 + ], + "angle": 0, + "content": "4.1.1 Goal-Oriented Static Planning (GOSP)" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.469, + 0.867 + ], + "angle": 0, + "content": "Given a high-level concise instruction, such as \"Empty the washing machine on level one\", an LLM is first asked to generate a goal-oriented static planning instruction: \"Goal:" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.37, + 0.892, + 0.702 + ], + "angle": 0, + "content": "The target object is a washing machine. It is usually in a laundry room\", which emphasizes the target object and points out where the target object may lie. As shown in Fig. 3(a), the planning generation mainly consists of two sub-tasks: target object recognition and target object localization, which can be achieved by providing specifically designed prompts for the LLM. To this end, we design the prompts for the former sub-task in the form: \"Task: Empty the washing machine on level one. Goal: The target object is:\". Then the LLM will generate a corresponding answer: \"washing machine\". By contrast, the latter subtask, reasoning out the target location, is more complex because it requires more suitable prompts to arouse the internalized world knowledge in the LLM. To address this problem, we utilize a fixed demonstration example for the LLM, and design the prompts for the latter sub-task in the form: \"Example: Question: Where does a microwave can usually appear in a house? Answer: kitchen. Question: Where does a washing machine can usually appear in a house? Answer: \". Given such prompts, the LLM will generate the corresponding answer \"laundry room\". With these answers, we can easily combine them into the goal-oriented planning format: \"Goal: The target object is a washing machine. It is usually in a laundry room\"." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.711, + 0.854, + 0.725 + ], + "angle": 0, + "content": "4.1.2 Scene-Oriented Dynamic Planning (SODP)" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.729, + 0.892, + 0.867 + ], + "angle": 0, + "content": "As is shown in Fig 3(b), the prompt for SODP consists of three parts. The first part is based on the scene perception of room type, such as \"bedroom\", and visible objects, such as \"bed, lamp, pillow\", obtained by the Room-and-Object Aware Scene Perceiver (ROASP, Sec. 4.2). These information are transformed into a natural language description of the current scene in the format of \"At this step, I am in bedroom, I can see bed, lamp, pillow\". The second part is a demonstration of the fine-grained step-by-step instruction, which is selected according to the strategy" + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.888, + 0.504, + 0.898 + ], + "angle": 0, + "content": "15761" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.092, + 0.13, + 0.118, + 0.139 + ], + "angle": 0, + "content": "R2R" + }, + { + "type": "text", + "bbox": [ + 0.092, + 0.14, + 0.443, + 0.16 + ], + "angle": 0, + "content": "Go up the stairs and then walk the length of the couch. Walk past the dining area and into the kitchen. Stop in front of the refrigerator." + }, + { + "type": "title", + "bbox": [ + 0.092, + 0.163, + 0.135, + 0.171 + ], + "angle": 0, + "content": "FGR2R" + }, + { + "type": "text", + "bbox": [ + 0.092, + 0.173, + 0.197, + 0.183 + ], + "angle": 0, + "content": "Step 1: go up the stair" + }, + { + "type": "text", + "bbox": [ + 0.092, + 0.183, + 0.302, + 0.192 + ], + "angle": 0, + "content": "Step 2: and then walk the length of the couch" + }, + { + "type": "text", + "bbox": [ + 0.092, + 0.193, + 0.337, + 0.202 + ], + "angle": 0, + "content": "Step 3: walk past the dining area and into the kitchen" + }, + { + "type": "text", + "bbox": [ + 0.092, + 0.202, + 0.27, + 0.212 + ], + "angle": 0, + "content": "Step 4: stop in front of the refrigerator" + }, + { + "type": "list", + "bbox": [ + 0.092, + 0.173, + 0.337, + 0.212 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.092, + 0.221, + 0.453, + 0.234 + ], + "angle": 0, + "content": "Figure 4: Example of instructions in R2R and FGR2R." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.248, + 0.469, + 0.331 + ], + "angle": 0, + "content": "detailed in the next section. The last part is previous instructions, such as \"Task: Empty the washing machine on level one. Step 1:\". All these three parts are concatenated together and then fed into an LLM to generate the fine-grained planning instruction for the next step accordingly, such as \"Exit the bedroom\"." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.34, + 0.369, + 0.353 + ], + "angle": 0, + "content": "4.1.3 Dynamic Demonstration Selection" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.357, + 0.469, + 0.467 + ], + "angle": 0, + "content": "Recent works show that providing various demonstration examples to LLMs benefits the in-context learning for different tasks [17, 22, 25]. In light of these findings, to direct the LLMs in generating better fine-grained plannings, we dynamically select the most suitable demonstration example for each specific task in REVERIE as the prompt to generate the environment-aware instruction, contrary to using a single fixed demonstration for all tasks." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.468, + 0.469, + 0.648 + ], + "angle": 0, + "content": "Specifically, we choose the training set of the Fine-Grained R2R dataset (FGR2R) [15] as the demonstration set \\(\\mathcal{D}\\), of which each sample will be used as a demonstration example \\(D_{step}\\). As shown in Fig. 4, FGR2R decomposes each low-level instruction \\(I_{low}\\) of R2R dataset [4] into step-by-step instructions \\(I_{step}\\). Then, given a high-level instruction \\(I_{high}\\) of REVERIE, a proper \\(I_{low}\\) will be selected as the demonstration example \\(D_{step}\\) by a matching algorithm. In particular, we use \\(I_{high}\\) as query \\(Q\\) and each low-level instruction \\(I_{low}\\) as the key \\(K_i\\), both of which are embedded by the Sentence-BERT [32]. The semantic distance score between the two embeddings is calculated by the cosine similarity:" + }, + { + "type": "equation", + "bbox": [ + 0.175, + 0.658, + 0.469, + 0.689 + ], + "angle": 0, + "content": "\\[\n\\mathrm {s} (Q, K _ {i}) = \\frac {e (Q) \\cdot e (K _ {i})}{\\| e (Q) \\| \\| e (K _ {i}) \\|}, \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.698, + 0.469, + 0.768 + ], + "angle": 0, + "content": "where \\( e(\\cdot) \\) is the embedding function. If \\( K_{i} \\) has the highest similarity score to the given query \\( Q \\), its corresponding step-by-step instruction \\( I_{step} \\) will be selected as the demonstration example \\( D_{step} \\) for the given high-level instruction \\( I_{high} \\)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.776, + 0.43, + 0.79 + ], + "angle": 0, + "content": "4.2. Room-and-Object Aware Scene Perceiver" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.798, + 0.469, + 0.866 + ], + "angle": 0, + "content": "Though the world knowledge acquired from the static LLMs planner could benefit the embodied task promisingly, the static LLMs planner may generate wrong or irrelevant plannings, which misleads the agent. To address this issue, the LLM planner should be aware of and interact with the" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.127, + 0.892, + 0.36 + ], + "angle": 0, + "content": "dynamic observations. In [35], the names of objects obtained from the ground truth or pre-trained detectors have been added to in-context prompts. However, the agents of these works act in a very limited space with simple scenes and monotonous objects. By contrast, REVERIE involves large-area exploration between different floors and rooms, where the scenes are more complex with more diverse objects. Considering these factors, we propose a room-and-object aware scene perceiver (ROASP) for the LLM planner, which predicts not only the room type but also the visible objects of the current location. Rather than using separate classifiers and detectors to individually predict each position's room types and visible object categories, we use CLIP [30] as the proposed room-and-object aware scene perceiver. Thanks to CLIP's strong ability of zero-shot image classification in the open world, the ROASP can well handle these two tasks." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.361, + 0.892, + 0.485 + ], + "angle": 0, + "content": "Specifically, we first fetch the room type labels from the MatterPort3D [6] semantic annotations and the object type labels are extracted from the REVERIE training dataset. They are used to build the codebook for the room categories \\(\\mathbf{C}_{\\mathrm{room}}\\) and the object categories \\(\\mathbf{C}_{\\mathrm{obj}}\\), respectively. Then, at each timestep \\(t\\), the agent perceives the environment and obtains the panoramic visual observation \\(\\mathcal{R}_t = \\{r_i\\}_{i=1}^n\\). For each single-view observation \\(r_i\\) in the panorama, the image feature \\(f_{\\mathrm{r}}\\) is extracted by the CLIP Image Encoder" + }, + { + "type": "equation", + "bbox": [ + 0.642, + 0.496, + 0.891, + 0.512 + ], + "angle": 0, + "content": "\\[\nf _ {\\mathrm {r}} = E _ {\\mathrm {C L I P}} ^ {v} \\left(r _ {i}\\right), \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.522, + 0.892, + 0.604 + ], + "angle": 0, + "content": "where \\( E_{\\mathrm{CLIP}}^v (\\cdot) \\) represents the CLIP Image Encoder. For each room category \\( c_{room} \\) and each object category \\( c_{obj} \\), we respectively construct a text phrase of room \\( T_{\\mathrm{room}} \\) as \"a photo of a \\( \\{c_{room}\\} \\)\" and a text phrase of object \\( T_{\\mathrm{obj}} \\) as \"a photo of a \\( \\{c_{obj}\\} \\)\". Then the text feature is derived through the pretrained CLIP Text Encoder as:" + }, + { + "type": "equation", + "bbox": [ + 0.621, + 0.615, + 0.891, + 0.631 + ], + "angle": 0, + "content": "\\[\nf _ {\\text {r o o m}} = E _ {\\text {C L I P}} ^ {t} \\left(T _ {\\text {r o o m}}\\right), \\tag {3}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.631, + 0.634, + 0.891, + 0.65 + ], + "angle": 0, + "content": "\\[\nf _ {\\mathrm {o b j}} = E _ {\\mathrm {C L I P}} ^ {t} \\left(T _ {\\mathrm {o b j}}\\right), \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.659, + 0.891, + 0.729 + ], + "angle": 0, + "content": "where \\( E_{\\mathrm{CLIP}}^{t}(\\cdot) \\) represents the CLIP Text Encoder. At last, the similarity score \\( S_{\\mathrm{room}} \\) between the image feature \\( f_{\\mathrm{r}} \\) and the text feature \\( f_{\\mathrm{room}} \\) as well as the similarity score \\( S_{\\mathrm{obj}} \\) between the image feature \\( f_{\\mathrm{r}} \\) and the text feature \\( f_{\\mathrm{obj}} \\) are respectively computed as:" + }, + { + "type": "equation", + "bbox": [ + 0.596, + 0.738, + 0.891, + 0.755 + ], + "angle": 0, + "content": "\\[\nS _ {\\text {r o o m}} = \\operatorname {S o f t m a x} \\left(f _ {\\text {r o o m}} \\cdot f _ {\\mathrm {r}} ^ {T}\\right), \\tag {5}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.607, + 0.757, + 0.891, + 0.774 + ], + "angle": 0, + "content": "\\[\nS _ {\\mathrm {o b j}} = \\operatorname {S o f t m a x} \\left(f _ {\\mathrm {o b j}} \\cdot f _ {\\mathrm {r}} ^ {T}\\right). \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.784, + 0.892, + 0.867 + ], + "angle": 0, + "content": "Considering that the current environment normally belongs to only one type of room, though the panoramic images have multiple views, the room that the agent is currently centered in should have the largest influence on each view. Thus, we average the predicted room type scores \\( S_{\\mathrm{room}} \\) from multiple views and choose the room type with" + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.887, + 0.505, + 0.898 + ], + "angle": 0, + "content": "15762" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.088, + 0.131, + 0.458, + 0.219 + ], + "angle": 0, + "content": "
HLIEmpty the washing machine on level one.
GOSPGoal: The target object is washing machine. It is usually in laundry room.
SODPStep 1: exit the bedroom\nStep 2: go down the stairs\n...
" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.226, + 0.47, + 0.282 + ], + "angle": 0, + "content": "Figure 5: Text inputs contains three parts: High-level Instruction in REVERIE (HLI), Goal-Oriented Static Planning (GOSP) and Scene-Oriented Dynamic Planning (SODP) returned instructions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.296, + 0.47, + 0.378 + ], + "angle": 0, + "content": "the greatest score as the room type prediction \\(\\hat{c}_{\\mathrm{room}}\\). For object predictions, if the object occupies more proportion in a view, the matching score \\(S_{\\mathrm{obj}}\\) should be higher. Thus, we select \\(k\\) prominent objects with the top-\\(k\\) matching scores as the auxiliary environment feedback in addition to the predicted room." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.388, + 0.38, + 0.404 + ], + "angle": 0, + "content": "4.3. March with Interactive Prompting" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.41, + 0.469, + 0.52 + ], + "angle": 0, + "content": "When the generation of the goal-oriented planning and the scene-oriented planning with perceptions from the environment is finished, the agent can march towards the target object at each timestep \\( t \\) under the guidance of the interactive prompting. In this section, we will give a detailed description of how the interactive prompting works during the process of navigation, which mainly consists of two parts, i.e. the assembled instruction and the instruction update." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.528, + 0.47, + 0.735 + ], + "angle": 0, + "content": "Assembled Instruction At each timestep \\( t \\), the agent observes the environment and receives the assembled instructions obtained from the above-mentioned modules, and choose an action to perform. Specifically, as shown in Fig. 5, the assembled instructions \\( W \\) of the interactive prompting mainly consist of three parts: the high-level instruction (HLI) \\( W_{I} \\) in REVERIE, the GOSP instruction \\( W_{G} \\) and the SODP instruction \\( W_{S} \\). We concatenate these three parts of instructions as the assembled instruction \\( W = [W_{I}, W_{G}, W_{S}] \\) and use WordPieces [20] to tokenize all the words into a sequence of tokens as the textual input for the agent. Then, the agent will act under the guidance of such assembled instruction. Note that the use of the original high-level instruction \\( W_{I} \\) can improve the model's tolerance on the noise of intermediate planning instructions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.742, + 0.47, + 0.867 + ], + "angle": 0, + "content": "Instruction Update The GOSP is only conducted once at the beginning of the task. While the SODP is conducted depending on the feedback of environments. Specifically, at each timestep \\( t \\), if the ROASP finds the room has changed where the predicted room \\( \\hat{c}_{\\mathrm{room}}^t \\) does not equal to \\( \\hat{c}_{\\mathrm{room}}^{t-1} \\), the SODP will be triggered again. Then, a new step-by-step instruction such as \"Step 2: go down the stairs\" for the next few steps will be generated by the LLM and added to the previous assembled instruction \\( W \\) after the last step-by-step" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.127, + 0.892, + 0.154 + ], + "angle": 0, + "content": "instruction of \"Step 1: exit the bedroom\". Then, the agent will act under the guidance of the updated instructions \\( W' \\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.168, + 0.625, + 0.183 + ], + "angle": 0, + "content": "5. Experiment" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.192, + 0.669, + 0.206 + ], + "angle": 0, + "content": "5.1. Evaluation Setup" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.213, + 0.892, + 0.309 + ], + "angle": 0, + "content": "Dataset REVERIE [27] contains 10,567 panoramic images within 90 buildings (4,140 target objects divided into 489 categories) and 21,702 instructions with 18 words on average. Each target viewpoint has 7 distinct panoramic objects with 50 bounding boxes on average. It consists of four splits: train, validation seen, validation unseen and test unseen." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.321, + 0.892, + 0.444 + ], + "angle": 0, + "content": "Evaluation Metrics The performance of agents is evaluated in two ways: navigation and object grounding. For the navigation sub-task, the metrics are Success Rate (SR), Oracle Success Rate (OSR), and Success weighted by Path Length [3] (SPL), where SPL is the main metric. For the grounding sub-task, the metrics are Remote Grounding Success rate (RGS) and RGS weighted by Path Length (RGSPL), where RGSPL is the main metric for this subtask. For all these metrics, higher is better." + }, + { + "type": "text", + "bbox": [ + 0.529, + 0.442, + 0.892, + 0.469 + ], + "angle": 0, + "content": "TL Trajectory Length measures the average length of all the predicted navigation trajectories in meters." + }, + { + "type": "text", + "bbox": [ + 0.53, + 0.47, + 0.891, + 0.51 + ], + "angle": 0, + "content": "SR Success Rate measures the ratio of successful tasks, of which the agent's stop location is less than 3 meters away from the target location." + }, + { + "type": "text", + "bbox": [ + 0.52, + 0.511, + 0.892, + 0.551 + ], + "angle": 0, + "content": "OSR Oracle Success Rate measures the ratio of tasks of which one of its trajectory viewpoints can observe the target object within 3 meters." + }, + { + "type": "text", + "bbox": [ + 0.52, + 0.553, + 0.892, + 0.606 + ], + "angle": 0, + "content": "SPL Success weighted by Path Length trades-off SR (Success Rate) against TL (Trajectory Length). It measures both the accuracy and efficiency of navigation." + }, + { + "type": "text", + "bbox": [ + 0.52, + 0.608, + 0.891, + 0.648 + ], + "angle": 0, + "content": "RGS Remote Grounding Success rate measures the ratio of tasks that successfully locate the target object." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.649, + 0.827, + 0.662 + ], + "angle": 0, + "content": "RGSPL RGS weighted by Path Length is RGS." + }, + { + "type": "list", + "bbox": [ + 0.5, + 0.442, + 0.892, + 0.662 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.683, + 0.892, + 0.807 + ], + "angle": 0, + "content": "Implementation Details Our model is trained on a single 3090 GPU for 30,000 iterations. We set the batch size to 4 and the learning rate to \\(1 \\times 10^{-5}\\). The best model is selected according to performance on the validation unseen split. We use the same pretrained model and augmented data as [10] for a fair comparison. For the LLMs, we use the public GPT-2 [31] model for in-context learning. For the scene preceptor, we keep the top 3 object predictions for each position." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.817, + 0.874, + 0.832 + ], + "angle": 0, + "content": "5.2. Comparison with State-of-The-Art Methods" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.839, + 0.892, + 0.866 + ], + "angle": 0, + "content": "As shown in Table 1, we compare MiC with the state-of-the-art methods on the REVERIE benchmark. Our method" + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.887, + 0.505, + 0.898 + ], + "angle": 0, + "content": "15763" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.123, + 0.124, + 0.85, + 0.353 + ], + "angle": 0, + "content": "
MethodsVal UnseenTest Unseen
NavigationGroundingNavigationGrounding
TLOSR↑SR↑SPL↑RGS↑RGSPL↑TLOSR↑SR↑SPL↑RGS↑RGSPL↑
Human------21.1886.8381.5153.6677.8451.44
Seq2Seq11.078.074.202.842.161.6310.896.883.993.092.001.58
RCM [37]11.9814.239.296.974.8910.607.843.8911.686.673.673.14
SMNA [23]9.0711.288.156.444.543.619.238.395.804.533.102.39
FAST-MATTN [27]45.2828.2014.407.197.844.6739.0530.6319.8811.6111.286.08
ORIST [26]10.9025.0216.8415.148.527.5811.3829.2022.1918.9710.689.28
CKR [12]26.2631.4419.1411.8411.45-22.4630.4022.0014.2511.60-
RecBERT [16]16.7835.0230.6724.9018.7715.2715.8632.9129.6123.9916.5013.51
Airbert [13]18.7134.5127.8921.8818.2314.1817.9134.2030.2823.6116.8313.28
HAMT [9]14.0836.8432.9530.2018.9217.2813.6233.4130.4026.6714.8812.08
HOP [28]16.4636.2431.7826.1118.8515.7316.3833.0630.1724.3417.6914.34
TD-STP [38]-39.4834.8827.3221.1616.56-40.2635.8927.5119.8815.40
DUET [11]22.1151.0746.9833.7332.1523.0321.3056.9152.5136.0631.8822.06
HM3D-DUET [10]-62.1455.8940.8536.5826.76-62.3055.1738.8832.2322.68
MiC20.6462.3756.9743.6037.5228.7218.1162.4055.7441.9735.2526.17
" + }, + { + "type": "table_caption", + "bbox": [ + 0.255, + 0.363, + 0.712, + 0.377 + ], + "angle": 0, + "content": "Table 1: Comparison with the state-of-the-art methods on REVERIE." + }, + { + "type": "table", + "bbox": [ + 0.092, + 0.39, + 0.459, + 0.468 + ], + "angle": 0, + "content": "
ComponentsNavigationGrounding
OSR↑SR↑SPL↑RGS↑RGSPL↑
HLI(Baseline)58.0252.7140.4934.9326.82
HLI+GOSP59.9255.2842.4637.1328.24
HLI+SODP60.7256.2642.9436.8027.81
HLI+GOSP+SODP62.3756.9743.6037.5228.72
" + }, + { + "type": "table_caption", + "bbox": [ + 0.105, + 0.477, + 0.439, + 0.491 + ], + "angle": 0, + "content": "Table 2: Ablation of different components in MiC." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.504, + 0.47, + 0.643 + ], + "angle": 0, + "content": "outperforms previous methods in all metrics on both validation unseen and test unseen splits. Particularly, compared with the SoTA method HM3D-DUET [10], MiC outperforms HM3D-DUET by a large margin of \\(3.09\\%\\) in terms of the main navigation metric SPL and \\(3.49\\%\\) of the main object grounding metric RGSPL on the Test Unseen split. Note that MiC shares the same pre-trained model with the HM3D-DUET, these promising result demonstrates that our method can effectively improve the navigation and object grounding ability of agents." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.651, + 0.251, + 0.667 + ], + "angle": 0, + "content": "5.3. Ablation Analysis" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.673, + 0.469, + 0.728 + ], + "angle": 0, + "content": "Contribution of different MiC Components In Table 2, we evaluate the effect of different components in our proposed MiC. HLI denotes only using the original high-level instruction (HLI) provided by REVERIE." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.729, + 0.469, + 0.867 + ], + "angle": 0, + "content": "Compared to the baseline HLI, GOSP improves the performance of both navigation \\((2.57\\% \\uparrow\\) on SR, \\(1.97\\% \\uparrow\\) on SPL) and object grounding \\((2.20\\% \\uparrow\\) on RGS, \\(1.42\\% \\uparrow\\) on RGSPL) with a non-trivial margin, showing the effectiveness of the proposed goal-oriented static planning. SODP further surpasses GOSP in the navigation metric \\((0.98\\% \\uparrow\\) on SR, \\(0.48\\% \\uparrow\\) on SPL) while falling a little behind in the grounding metrics \\((0.33\\% \\uparrow\\) on RGS, \\(1.43\\% \\uparrow\\) on RGSPL). The reason may be that the detailed step-by-step planning occupies a large proportion compared to the target object" + }, + { + "type": "table", + "bbox": [ + 0.524, + 0.39, + 0.871, + 0.464 + ], + "angle": 0, + "content": "
MethodsNavigationGrounding
OSR↑SR↑SPL↑RGS↑RGSPL↑
Baseline58.0252.7140.4934.9326.82
Static60.2455.3541.7436.3027.03
Dynamic60.7256.2642.9436.8027.81
" + }, + { + "type": "table_caption", + "bbox": [ + 0.504, + 0.474, + 0.886, + 0.488 + ], + "angle": 0, + "content": "Table 3: Comparison of different plan generation settings." + }, + { + "type": "table", + "bbox": [ + 0.506, + 0.504, + 0.89, + 0.564 + ], + "angle": 0, + "content": "
MethodsRelevancyRationality
Scene-Oriented Dynamic Planning2.061.93
- w/o Dynamic Demonstration1.411.23
- w/o ROASP1.641.55
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.574, + 0.891, + 0.601 + ], + "angle": 0, + "content": "Table 4: Human study of the prompt setting for Scene-Oriented Dynamic Planning." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.617, + 0.892, + 0.727 + ], + "angle": 0, + "content": "in the input texts, which can bring the noise for object grounding while improving navigation performance. When combining all these components, the final performance gets further increased in all metrics, which surpasses the baseline with a large margin (4.26%↑ on SR, 3.11%↑ on SPL, 2.59%↑ on RGS and 1.9%↑ on RGSPL). The promising results here show that these components are complementary to each other." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.742, + 0.892, + 0.867 + ], + "angle": 0, + "content": "The Effect of the ROASP To evaluate the effectiveness of ROASP used for the scene-oriented dynamic planning, we conduct another ablation study via whether incorporating the feedback from the ROASP module on REVERIE validation unseen set. We report results in three settings: (I) Baseline: The input assembled instruction only contains the given high-level instruction in REVERIE. (II) Static: The input assembled instruction contains the REVERIE and fine-grained static instructions. The difference between" + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.887, + 0.505, + 0.898 + ], + "angle": 0, + "content": "15764" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.097, + 0.131, + 0.877, + 0.35 + ], + "angle": 0, + "content": "
REVERIE Instruction: Go to the bathroom with the two towels and empty the lower cabinet.
Scene-Oriented Dynamic Planningw/o Dynamic Demonstrationw/o ROASP
Step 1: exit the bedroomStep 1: put the towel in the bottom drawer of the toiletStep 1: exit the bathroom
Step 2: and walk into the next bedroom in the hallStep 2: walk into the kitchen
Step 3: go stand in the kitchen doorway
Step 3: go stand in the bathroomStep 4: go back to the bedroom and take the towel
Step 5: exit the bedroom
Step 6: walk into the next bedroom in the hall
REVERIE Instruction: Go to the kitchen on level 2 and open the drawer.
Scene-Oriented Dynamic Planningw/o Dynamic Demonstrationw/o ROASP
Step 1: go upstairsStep 1: open the drawer with the key in itStep 1: go upstairs and turn left at the hall
Step 2: go straight pass the couchStep 2: remove the lock from the doorStep 2: go back down the stairs
Step 3: make a slight left towards the refrigeratorStep 3: then turn onStep 3: go up the stairs again
Step 4: wait near the kitchen drawerStep 4: go back to the kitchen and open the fridge
Step 5: take out the fruit and put it in the juicer
" + }, + { + "type": "image_caption", + "bbox": [ + 0.333, + 0.36, + 0.635, + 0.374 + ], + "angle": 0, + "content": "Figure 6: Examples of generated instructions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.382, + 0.473, + 0.576 + ], + "angle": 0, + "content": "fine-grained static instruction and scene-oriented dynamic instruction is that static fine-grained instruction is generated without ROASP. More specifically, the query prompt for the LLM to generate step-by-step planning is fixed at each timestep, which only consists of the given high-level instruction and the selected demonstration. (III) Dynamic: The input assembled instruction contains the high-level instruction in REVERIE and scene-oriented dynamic planning instruction. As shown in Table 3, in the static setting, the performance in all metrics is improved compared to the baseline, indicating the effectiveness of the LLM's rich world knowledge in fine-grained planning. In the dynamic setting, the performance is further improved with non-trivial margins, showing the effectiveness of ROASP." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.591, + 0.47, + 0.839 + ], + "angle": 0, + "content": "Qualitative Analysis of Prompt Setting To further evaluate the effect of dynamic demonstration and ROASP in SODP, we perform a human evaluation about the generated plannings (see Table 4) and show the planning results (see Fig. 6). For human evaluation, we randomly selected 100 REVERIE tasks and generate fine-grained step-by-step instructions in setting of SODP, SODP without dynamic demonstration, and SODP without ROASP. We asked 10 volunteers to mark the generated step-by-step instructions in terms of their relevancy and rationality. The relevancy score ranges from 0 (unrelated) to 3 (very related), which takes into account whether the keywords in instructions are related to the REVERIE task. For example, regarding the REVERIE instruction \"Go to the kitchen and turn on the microwave\", whether there are keywords in instructions related to the kitchen scene could be rated. Rationality is rated from 0 (bad) to 3 (perfect), considering whether the instruction conforms to the logic of navigation." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.839, + 0.47, + 0.867 + ], + "angle": 0, + "content": "The results are presented in Table 4. It shows that our SODP scored 2.06 on Relevancy and 1.93 on Rational-" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.382, + 0.892, + 0.617 + ], + "angle": 0, + "content": "ity, which could be considered acceptable since the highest score is 3 and it is challenging to generate instructions that are consistent with tasks and actual navigation logic. When removing the dynamic demonstration, the score of generated instruction drops about \\(31.55\\%\\) on Relevancy and \\(36.27\\%\\) on Rationality, which could also be observed in Fig. 6. Although the instruction generated without dynamic demonstration is related to the task to some extent (e.g., \"put the towel in the bottom drawer of the toilet\" has the keyword \"towel\", the instruction lacks navigation information, such as how to reach the bathroom.) As shown in the bottom example of Fig. 6, instruction without ROASP successfully guided how to go to the destination location kitchen, but it still caused confusion by going upstairs and going downstairs several times, and thus reducing the rationality score, i.e. 1.64 on Relevancy and 1.55 on Rationality. More generation results can be found in the supplementary." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.628, + 0.627, + 0.643 + ], + "angle": 0, + "content": "6. Conclusions" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.652, + 0.892, + 0.803 + ], + "angle": 0, + "content": "In this work, we propose a novel model, March-in-Chat (MiC), for the REVEIRE task, which only provides concise high-level instructions for the VLN agent. MiC enables the REVERIE agent to talk with an LLM on the fly to generate plans for the next few steps. It consists of three main modules, Goal-Oriented Static Planning (GOSP), Scene-Oriented Dynamic Planning (SODP), and Room-and-Object Aware Scene Perceiver (ROASP) module. We conduct extensive quantitative and qualitative experiments on REVERIE and the promising results show the effectiveness of our method." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.816, + 0.676, + 0.832 + ], + "angle": 0, + "content": "7. Acknowledgements" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.839, + 0.892, + 0.867 + ], + "angle": 0, + "content": "Jing Liu is supported by the National Key Research and Development Program of China (No. 2020AAA0106400)." + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.887, + 0.505, + 0.898 + ], + "angle": 0, + "content": "15765" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.125, + 0.174, + 0.14 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.148, + 0.47, + 0.325 + ], + "angle": 0, + "content": "[1] Michael Ahn, Anthony Brohan, Noah Brown, Yevgen Chebotar, Omar Cortes, Byron David, Chelsea Finn, Chuyuan Fu, Keerthana Gopalakrishnan, Karol Hausman, Alex Herzog, Daniel Ho, Jasmine Hsu, Julian Ibarz, Brian Ichter, Alex Irpan, Eric Jang, Rosario Jauregui Ruano, Kyle Jeffrey, Sally Jesmonth, Nikhil Joshi, Ryan Julian, Dmitry Kalashnikov, Yuheng Kuang, Kuang-Huei Lee, Sergey Levine, Yao Lu, Linda Luu, Carolina Parada, Peter Pastor, Jornell Quiambao, Kanishka Rao, Jarek Rettinghouse, Diego Reyes, Pierre Sermanet, Nicolas Sievers, Clayton Tan, Alexander Toshev, Vincent Vanhoucke, Fei Xia, Ted Xiao, Peng Xu, Sichun Xu, Mengyuan Yan, and Andy Zeng. Do as i can and not as i say: Grounding language in robotic affordances. In arXiv preprint arXiv:2204.01691, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.327, + 0.47, + 0.377 + ], + "angle": 0, + "content": "[2] Dong An, Yuankai Qi, Yangguang Li, Yan Huang, Liang Wang, Tieniu Tan, and Jing Shao. Bevbert: Topo-metric map pre-training for language-guided navigation. arXiv preprint arXiv:2212.04385, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.379, + 0.469, + 0.442 + ], + "angle": 0, + "content": "[3] Peter Anderson, Angel X. Chang, Devendra Singh Chaplot, Alexey Dosovitskiy, Saurabh Gupta, Vladlen Koltun, Jana Kosecka, Jitendra Malik, Roozbeh Mottaghi, Manolis Savva, and Amir Roshan Zamir. On evaluation of embodied navigation agents. CoRR, abs/1807.06757, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.444, + 0.469, + 0.506 + ], + "angle": 0, + "content": "[4] Peter Anderson, Qi Wu, Damien Teney, Jake Bruce, Mark Johnson, Niko Sünderhauf, Ian D. Reid, Stephen Gould, and Anton van den Hengel. Vision-and-language navigation: Interpreting visually-grounded navigation instructions in real environments. In CVPR, pages 3674-3683, 2018. 1, 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.508, + 0.469, + 0.634 + ], + "angle": 0, + "content": "[5] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, Sandhini Agarwal, Ariel Herbert-Voss, Gretchen Krueger, Tom Henighan, Rewon Child, Aditya Ramesh, Daniel Ziegler, Jeffrey Wu, Clemens Winter, Chris Hesse, Mark Chen, Eric Sigler, Mateusz Litwin, Scott Gray, Benjamin Chess, Jack Clark, Christopher Berner, Sam McCandlish, Alec Radford, Ilya Sutskever, and Dario Amodei. Language models are few-shot learners. In NeurIPS, pages 1877-1901, 2020. 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.636, + 0.469, + 0.698 + ], + "angle": 0, + "content": "[6] Angel X. Chang, Angela Dai, Thomas A. Funkhouser, Macej Halber, Matthias Nießner, Manolis Savva, Shuran Song, Andy Zeng, and Yinda Zhang. Matterport3d: Learning from RGB-D data in indoor environments. In 3DV, pages 667-676, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.7, + 0.469, + 0.75 + ], + "angle": 0, + "content": "[7] Howard Chen, Alane Suhr, Dipendra Misra, Noah Snavely, and Yoav Artzi. TOUCHDOWN: natural language navigation and spatial reasoning in visual street environments. In CVPR, pages 12538-12547, 2019. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.752, + 0.469, + 0.814 + ], + "angle": 0, + "content": "[8] Mark Chen, Jerry Tworek, Heewoo Jun, Qiming Yuan, Henrique Ponde de Oliveira Pinto, Jared Kaplan, Harri Edwards, Yuri Burda, Nicholas Joseph, Greg Brockman, et al. Evaluating large language models trained on code. arXiv preprint arXiv:2107.03374, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.816, + 0.469, + 0.866 + ], + "angle": 0, + "content": "[9] Shizhe Chen, Pierre-Louis Guhur, Cordelia Schmid, and Ivan Laptev. History aware multimodal transformer for vision-and-language navigation. In NeurIPS, pages 5834-5847, 2021. 7" + }, + { + "type": "list", + "bbox": [ + 0.087, + 0.148, + 0.47, + 0.866 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.128, + 0.892, + 0.178 + ], + "angle": 0, + "content": "[10] Shizhe Chen, Pierre-Louis Guhur, Makarand Tapaswi, Cordelia Schmid, and Ivan Laptev. Learning from unlabeled 3d environments for vision-and-language navigation. In ECCV, 2022. 4, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.18, + 0.892, + 0.23 + ], + "angle": 0, + "content": "[11] Shizhe Chen, Pierre-Louis Guhur, Makarand Tapaswi, Cordelia Schmid, and Ivan Laptev. Think global, act local: Dual-scale graph transformer for vision-and-language navigation. In CVPR, 2022. 2, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.232, + 0.892, + 0.282 + ], + "angle": 0, + "content": "[12] Chen Gao, Jinyu Chen, Si Liu, Luting Wang, Qiong Zhang, and Qi Wu. Room-and-object aware knowledge reasoning for remote embodied referring expression. In CVPR, pages 3064-3073, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.284, + 0.892, + 0.333 + ], + "angle": 0, + "content": "[13] Pierre-Louis Guhur, Makarand Tapaswi, Shizhe Chen, Ivan Laptev, and Cordelia Schmid. Airbert: In-domain pretraining for vision-and-language navigation. In ICCV, pages 1634-1643, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.335, + 0.892, + 0.386 + ], + "angle": 0, + "content": "[14] Keji He, Yan Huang, Qi Wu, Jianhua Yang, Dong An, Shuanglin Sima, and Liang Wang. Landmark-rxr: Solving vision-and-language navigation with fine-grained alignment supervision. NeurIPS, 34:652-663, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.388, + 0.892, + 0.439 + ], + "angle": 0, + "content": "[15] Yicong Hong, Cristian Rodriguez Opazo, Qi Wu, and Stephen Gould. Sub-instruction aware vision-and-language navigation. In Bonnie Webber, Trevor Cohn, Yulan He, and Yang Liu, editors, EMNLP, pages 3360-3376, 2020. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.44, + 0.892, + 0.49 + ], + "angle": 0, + "content": "[16] Yicong Hong, Qi Wu, Yuankai Qi, Cristian Rodriguez Opazo, and Stephen Gould. VLN\\(\\text{©}\\) BERT: A recurrent vision-and-language BERT for navigation. In CVPR, pages 1643-1653, 2021. 2, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.492, + 0.892, + 0.543 + ], + "angle": 0, + "content": "[17] Wenlong Huang, Pieter Abbeel, Deepak Pathak, and Igor Mordatch. Language models as zero-shot planners: Extracting actionable knowledge for embodied agents. In ICML, pages 9118-9147. PMLR, 2022. 2, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.545, + 0.892, + 0.632 + ], + "angle": 0, + "content": "[18] Wenlong Huang, Fei Xia, Ted Xiao, Harris Chan, Jacky Liang, Pete Florence, Andy Zeng, Jonathan Tompson, Igor Mordatch, Yevgen Chebotar, Pierre Sermanet, Noah Brown, Tomas Jackson, Linda Luu, Sergey Levine, Karol Hausman, and Brian Ichter. Inner monologue: Embodied reasoning through planning with language models. In arXiv preprint arXiv:2207.05608, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.634, + 0.892, + 0.685 + ], + "angle": 0, + "content": "[19] Vihan Jain, Gabriel Magalhães, Alexander Ku, Ashish Vaswani, Eugene Ie, and Jason Baldridge. Stay on the path: Instruction fidelity in vision-and-language navigation. pages 1862-1872, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.687, + 0.892, + 0.762 + ], + "angle": 0, + "content": "[20] Melvin Johnson, Mike Schuster, Quoc V. Le, Maxim Krikun, Yonghui Wu, Zhifeng Chen, Nikhil Thorat, Fernanda B. Viégas, Martin Wattenberg, Greg Corrado, Macduff Hughes, and Jeffrey Dean. Google's multilingual neural machine translation system: Enabling zero-shot translation. Trans. Assoc. Comput. Linguistics, 5:339-351, 2017. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.764, + 0.892, + 0.814 + ], + "angle": 0, + "content": "[21] Alexander Ku, Peter Anderson, Roma Patel, Eugene Ie, and Jason Baldridge. Room-across-room: Multilingual vision-and-language navigation with dense spatiotemporal grounding. In EMNLP, pages 4392-4412, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.816, + 0.892, + 0.866 + ], + "angle": 0, + "content": "[22] Jiachang Liu, Dinghan Shen, Yizhe Zhang, Bill Dolan, Lawrence Carin, and Weizhu Chen. What makes good in-context examples for gpt-3? arXiv preprint arXiv:2101.06804, 2021. 5" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.128, + 0.892, + 0.866 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.467, + 0.888, + 0.505, + 0.898 + ], + "angle": 0, + "content": "15766" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.127, + 0.47, + 0.178 + ], + "angle": 0, + "content": "[23] Chih-Yao Ma, Jiasen Lu, Zuxuan Wu, Ghassan AlRegib, Zsolt Kira, Richard Socher, and Caiming Xiong. Self-monitoring navigation agent via auxiliary progress estimation. In ICLR, 2019. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.18, + 0.469, + 0.231 + ], + "angle": 0, + "content": "[24] Khanh Nguyen and Hal Daumé III. Help, anna! visual navigation with natural multimodal assistance via retrospective curiosity-encouraging imitation learning. pages 684–695. Association for Computational Linguistics, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.232, + 0.469, + 0.282 + ], + "angle": 0, + "content": "[25] Gabriel Poesia, Alex Polozov, Vu Le, Ashish Tiwari, Gustavo Soares, Christopher Meek, and Sumit Gulwani. Synchromesh: Reliable code generation from pre-trained language models. In ICLR, 2022. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.284, + 0.469, + 0.347 + ], + "angle": 0, + "content": "[26] Yuankai Qi, Zizheng Pan, Yicong Hong, Ming-Hsuan Yang, Anton van den Hengel, and Qi Wu. The road to knowwhere: An object-and-room informed sequential bert for indoor vision-language navigation. In ICCV, pages 1655-1664, 2021. 2, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.349, + 0.469, + 0.411 + ], + "angle": 0, + "content": "[27] Yuankai Qi, Qi Wu, Peter Anderson, Xin Wang, William Yang Wang, Chunhua Shen, and Anton van den Hengel. REVERIE: remote embodied visual referring expression in real indoor environments. In CVPR, pages 9979-9988, 2020. 1, 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.413, + 0.469, + 0.463 + ], + "angle": 0, + "content": "[28] Yanyuan Qiao, Yuankai Qi, Yicong Hong, Zheng Yu, Peng Wang, and Qi Wu. HOP: history-and-order aware pretraining for vision-and-language navigation. In CVPR, pages 15397-15406, 2022. 2, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.465, + 0.469, + 0.515 + ], + "angle": 0, + "content": "[29] Yanyuan Qiao, Yuankai Qi, Yicong Hong, Zheng Yu, Peng Wang, and Qi Wu. Hop+: History-enhanced and order-aware pre-training for vision-and-language navigation. IEEE TPAMI, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.517, + 0.469, + 0.594 + ], + "angle": 0, + "content": "[30] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, Gretchen Krueger, and Ilya Sutskever. Learning transferable visual models from natural language supervision. In ICML, volume 139, pages 8748-8763, 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.595, + 0.469, + 0.644 + ], + "angle": 0, + "content": "[31] Alec Radford, Jeffrey Wu, Rewon Child, David Luan, Dario Amodei, Ilya Sutskever, et al. Language models are unsupervised multitask learners. OpenAI blog, 1(8):9, 2019. 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.647, + 0.469, + 0.697 + ], + "angle": 0, + "content": "[32] Nils Reimers and Iryna Gurevych. Sentence-bert: Sentence embeddings using siamese bert-networks. In Kentaro Inui, Jing Jiang, Vincent Ng, and Xiaojun Wan, editors, EMNLP-IJCNLP, pages 3980-3990, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.699, + 0.469, + 0.761 + ], + "angle": 0, + "content": "[33] Mohit Shridhar, Jesse Thomason, Daniel Gordon, Yonatan Bisk, Winson Han, Roozbeh Mottaghi, Luke Zettlemoyer, and Dieter Fox. ALFRED: A benchmark for interpreting grounded instructions for everyday tasks. In CVPR, pages 10737-10746, 2020. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.763, + 0.469, + 0.814 + ], + "angle": 0, + "content": "[34] Ishika Singh, Valts Blukis, Arsalan Mousavian, Ankit Goyal, Danfei Xu, Jonathan Tremblay, Dieter Fox, Jesse Thomason, and Animesh Garg. ProgPrompt: Generating situated robot task plans using large language models. 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.816, + 0.469, + 0.867 + ], + "angle": 0, + "content": "[35] Chan Hee Song, Jiaman Wu, Clayton Washington, Brian M Sadler, Wei-Lun Chao, and Yu Su. Llm-planner: Few-shot grounded planning for embodied agents with large language models. arXiv preprint arXiv:2212.04088, 2022. 3, 5" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.127, + 0.47, + 0.867 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.127, + 0.892, + 0.165 + ], + "angle": 0, + "content": "[36] Jesse Thomason, Michael Murray, Maya Cakmak, and Luke Zettlemoyer. Vision-and-dialog navigation. In CoRL, pages 394-406, 2019. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.167, + 0.892, + 0.23 + ], + "angle": 0, + "content": "[37] Xin Wang, Qiuyuan Huang, Asli Celikyilmaz, Jianfeng Gao, Dinghan Shen, Yuan-Fang Wang, William Yang Wang, and Lei Zhang. Reinforced cross-modal matching and self-supervised imitation learning for vision-language navigation. In CVPR, pages 6629-6638, 2019. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.231, + 0.892, + 0.281 + ], + "angle": 0, + "content": "[38] Yusheng Zhao, Jinyu Chen, Chen Gao, Wenguan Wang, Lirong Yang, Haibing Ren, Huaxia Xia, and Si Liu. Target-driven structured transformer planner for vision-language navigation. pages 4194-4203, 2022. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.282, + 0.892, + 0.333 + ], + "angle": 0, + "content": "[39] Fengda Zhu, Xiwen Liang, Yi Zhu, Qizhi Yu, Xiaojun Chang, and Xiaodan Liang. SOON: scenario oriented object navigation with graph-based exploration. In CVPR, pages 12689-12699, 2021. 1, 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.127, + 0.892, + 0.333 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.467, + 0.887, + 0.505, + 0.898 + ], + "angle": 0, + "content": "15767" + } + ] +] \ No newline at end of file diff --git a/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/dfdb2c34-61fe-4960-a099-a29f68122739_origin.pdf b/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/dfdb2c34-61fe-4960-a099-a29f68122739_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..1eef2513fa45b2efff9ec5f5929598f83ea6f826 --- /dev/null +++ b/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/dfdb2c34-61fe-4960-a099-a29f68122739_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:8c7d4cd53755eaa217772b5f750f86304fb7ec6abe225347a084979b50d2eb2e +size 492616 diff --git a/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/full.md b/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/full.md new file mode 100644 index 0000000000000000000000000000000000000000..117c1bd59db6c19bfb2c87ed948da712db47dfe5 --- /dev/null +++ b/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/full.md @@ -0,0 +1,330 @@ +# March in Chat: Interactive Prompting for Remote Embodied Referring Expression + +Yanyuan Qiao $^{1}$ Yuankai Qi $^{1}$ Zheng Yu $^{1}$ Jing Liu $^{2,3}$ Qi Wu $^{1*}$ + +$^{1}$ Australian Institute for Machine Learning, The University of Adelaide + +$^{2}$ Institute of Automation, Chinese Academy of Sciences + +$^{3}$ School of Artificial Intelligence, University of Chinese Academy of Sciences + +{yanyuan.qiao,zheng.yu,qi.wu01}@adelaide.edu.au, qykshr@gmail.com,jliu@nlpr.ia.ac.cn + +# Abstract + +Many Vision-and-Language Navigation (VLN) tasks have been proposed in recent years, from room-based to object-based and indoor to outdoor. The REVERIE (Remote Embodied Referring Expression) is interesting since it only provides high-level instructions to the agent, which are closer to human commands in practice. Nevertheless, this poses more challenges than other VLN tasks since it requires agents to infer a navigation plan only based on a short instruction. Large Language Models (LLMs) show great potential in robot action planning by providing proper prompts. Still, this strategy has not been explored under the REVERIE settings. There are several new challenges. For example, the LLM should be environment-aware so that the navigation plan can be adjusted based on the current visual observation. Moreover, the LLM planned actions should be adaptable to the much larger and more complex REVERIE environment. This paper proposes a March-in-Chat (MiC) model that can talk to the LLM on the fly and plan dynamically based on a newly proposed Room-and-Object Aware Scene Perceiver (ROASP). Our MiC model outperforms the previous state-of-the-art by large margins by SPL and RGSPL metrics on the REVERIE benchmark. The source code is available at https://github.com/YanyuanQiao/MiC + +# 1. Introduction + +Vision-and-Language Navigation (VLN), which lies at the intersection of computer vision, natural language processing and robotics, has aroused great attention from research communities in the past few years. Given instructions in natural language, the VLN agent should navigate to the target location based on the dynamic observations in the 3D simulated environments. Since VLN has great + +![](images/8f6ac22cb1ca7ce66006da99c22e278d7607c56e42a86de54ec831bc88a4072c.jpg) +REVERIE Instruction: Clean the small picture in front of the large mirror. +Figure 1: Our March-in-Chat (MiC) model is talking to a Large Language Model (LLM) to generate navigation plans on the fly, with the REVERIE instruction and the dynamic room-and-object information as inputs. + +potential in real-world applications such as domestic assistant robots, a large amount of specific VLN tasks have been proposed, including R2R [4] and RxR [21] that ask the agent to navigate from one room to another in a photorealistic environment according to the fine-grained instruction, NDH [36] provides detailed dialogues which imply the instruction, TouchDown [7] extends the task into an outdoor environment, REVERIE [27] and SOON [39] that additionally require the agent's ability of remote object grounding and ALFRED [33] that asks the agent to interact with the target object in a single room of the synthetic environment. + +Most of these VLN tasks provide detailed step-by-step instructions to the agent, such as "Go up the stairs and then walk the length of the couch. Walk past the dining area and into the kitchen. Stop in front of the refrigerator." in R2R. Although detailed instructions can help the agent better achieve the navigation goal in the simulated environments, it has a big gap towards real applications where human beings tend to give coarse-grained high-level instructions such as "Go to the refrigerator on the second floor". + +Contrary to other tasks, the Remote Embodied Referring Expression (REVERIE) task is more likely to empower the real-world applications of VLN, of which the instructions are closer to those in practice, such as "Empty the washing machine on level one". Such high-level instruction is more challenging for VLN agents since it requires them to be more competent in perceiving the surrounding environment and the navigation progress and correspondingly making reasonable plans for the next steps. + +Recently, Large Language Models (LLMs) that internalize a wealth of commonsense knowledge show great potential in action planning for some embodied tasks with the help of suitable in-context learning. However, previous works mainly utilize LLMs to plan atomic actions of object manipulation in a very limited space with simple scenes. These predefined atomic actions can be easily planned well by the LLMs planners with a unified template. Different from these embodied tasks, REVERIE requires large-area exploration from one room to another, which is complex in the layout of rooms and scenes with diverse objects. + +In this work, to adapt LLMs as the planner for REVERIE with the ability of comprehensive scene perception, we propose a novel model named March in Chat (MiC), which enables the LLM as an environment-aware instruction planner through on-the-fly dialogues between the agent and the LLM as Fig. 1 shows. Specifically, the agent is initially situated at the starting position given a high-level coarse-grained REVERIE instruction. First, a Goal-Oriented Static Planning (GOSP) module queries the LLM to point out the target object and infer where the thing may be by using the rich world knowledge internalized in the LLM. Secondly, the agent's Room-and-Object Aware Scene Perceiver (ROASP) describes the current observation and asks the LLM to generate step-by-step fine-grained planning for the next navigation steps. Then, if the ROASP finds the room has changed, the LLM is queried again by the Scene-Oriented Dynamic Planning (SODP) module to generate a new fine-grained step-by-step planning, which will be concatenated with all previous responses from the LLM. The agent will march under the guidance of such interactive prompting until the task is finished. + +To evaluate our proposed MiC, we conduct experiments on the REVERIE benchmark. Our MiC achieves a new state-of-the-art performance in all metrics on REVERIE val unseen set and REVERIE test unseen set. Mainly, MiC obtains $41.97\%$ on the primary navigation metric of SPL and $26.17\%$ on the major object grounding metric of RGSPL on test split, which is at least $3.09\%$ and $3.49\%$ higher than the previous SoTA results. We also conduct ablation studies to validate the contributions of different components in MiC and the effect of scene-aware perception in dynamic planning generation. These promising results demonstrate the effectiveness of our proposed MiC. + +In summary, we make the following contributions: + +- We propose a novel March-in-Chat (MiC) model, which lets the REVERIE agent talk with an LLM on the fly to make plans for the next few steps. +- Two planning modules, namely Goal-Oriented Static Planning (GOSP) module, and Scene-Oriented Dynamic Planning (SODP) module, and one Room-and-Object Aware Scene Perceiver (ROASP) module, are proposed. +- Extensive quantitative and qualitative experiments are conducted on REVERIE to validate the effectiveness of our method. + +# 2. Related work + +Vision-and-Language Navigation Vision-and-Language Navigation (VLN) has attracted increasing attention in recent years, and many specific VLN tasks have been proposed [7, 19, 24, 27, 29, 36]. Anderson et al. [4] proposes the first VLN benchmark, Room-to-Room (R2R), which requires an agent to navigate from one room to another in a house, according to a detailed natural language step-by-step instruction in a photo-realistic environment. Later, Room-across-Room (RxR) [21] was proposed with longer and more detailed multilingual instructions. Both these two tasks give fine-grained instructions, which makes it easier to navigate to the target location. NDH [36] extends the navigation instruction to the dialogue form, and TouchDown [7] extends the environments to outdoor. REVERIE [27] and SOON [39] are proposed for remote object localization, which requires an agent not only to navigate to the target location, but also to specify the object to interact with. The difference between REVERIE and SOON is that REVERIE uses short concise instructions (e.g., "bring me the red cup from the kitchen.") while SOON employs long detailed instructions (e.g., "I want to find a cylindrical, metallic and tall lamp, which is set in the bright living room. The lamp is on the cabinet which is on the left of the television and next to the window. The living room is on ..."). + +Among the aforementioned VLN tasks, the instructions of REVERIE are closer to what we would say to an intelligent domestic robot in daily life in terms of the instruction length and logic, which is usually short and concise. However, most existing methods [2, 11, 14, 16, 26, 28] are usually designed for the VLN tasks where detailed step-by-step instructions are used, thus they do not perform well on REVERIE. In this work, we specifically develop a method for REVERIE. Inspired by the fact of LLMs that implicitly internalize rich knowledge in action planning, we propose to exploit LLM as a fine-grained planner to generate detailed navigation plans from the concise instructions of REVERIE to improve navigation success. + +LLMs as Embodied Planner Benefiting from the rise of LLMs, recent works [17, 34] have explored the use of LLMs + +![](images/2d287ec19b9b3dacf1b36e1f271e5271bca29e9fc29f2915cae0c7ef9fcdc46a.jpg) + +![](images/2da1df1ad04dc53bc1e070729fc1fa91427a6ca4d5af948960bc2bbf0b0e3568.jpg) + +![](images/1b049502b19f12fe0ae918c8b89a5c491aa4c61228cb763ae4f1c5175ffce99e.jpg) + +![](images/ddb2fd4827834db8178e14901a821a6aa28659560df8d09f7fc9cf04195e11b2.jpg) +REVERIE instruction: Empty the washing machine on level one. +Figure 2: Overview of our March-in-Chat model. The program runs along the vertical arrows from left to right, progressing with the time flow. Our model first performs Goal-Oriented Static Planning (GOSP, Sec. 4.1.1) to reason the target object and its possible lying room; then the Room-and-Object Aware Scene Perceiver (ROASP, Sec. 4.2) perceives what room type the agent currently stands in and what prominent objects can be seen; these information are used by the Scene-Oriented Dynamic Planning module (SODP, Sec. 4.1.2) to generate a detailed instruction to execute. GOSP just runs once, and we repeat ROASP and SODP until the agent chooses to stop or reaches the maximum steps. + +in task planning for various embodied tasks. Huang et al. [17] propose to utilize the frozen LLMs (e.g., GPT-2 [31], GPT-3 [5] and Codex [8]) to plan actions for the embodied agent with in-context learning [5]. SayCan [1] translates a high-level instruction into a list of candidate low-level actions with a probability, which is then multiplied by a value function for action prediction. These two LLM planners are static, which only generate action plans at the beginning of a task. By contrast, Huang et al. [18] propose to introduce the feedback of action progress, detected objects and human assistance into the LLM planner to re-plan atomic actions. One concurrent work by Song et al. [35] injects the detected objects to re-generate high-level plans with a fixed program pattern for the ALFRED [33] task. + +However, these above-mentioned methods mainly concentrate on planning atomic actions for object manipulation in a very limited space with simple scenes. By contrast, REVERIE has plenty of much larger and more complicated environments: 90 multi-layer buildings of various styles (e.g., office, home, gym, to name a few). To handle the complex scenarios of REVERIE, we propose a Room-and-Object Aware Scene Perceiver module that helps the LLM planner dynamically interact with the environment in the form of a natural language dialogue. + +# 3. Problem Setup + +In the REVERIE task, given a concise and high-level instruction referring to a remote object, the agent is expected to navigate to the goal location and identify the target object in previously unseen environments. The environment is defined as an undirected graph $\mathcal{G} = \{\mathcal{V},\mathcal{E}\}$ , where + +$\mathcal{V} = \{V_i\}_{i=1}^K$ denotes $K$ navigable nodes, and $\mathcal{E}$ denotes connectivity edges. The agent is first placed in a starting node with the initial state $s_0$ and perceives a panorama $\mathcal{R}_t$ as the visual observation at each time step $t$ . The panorama $\mathcal{R}_t$ is split into $n$ single view images as $\mathcal{R}_t = \{r_i\}_{i=1}^n$ . Each single view image $r_i$ is represented by an image feature vector and an orientation feature vector. In addition, the object features $\mathcal{O}_t = \{o_i\}_{i=1}^m$ of $m$ objects are extracted from the panorama view using the annotated object bounding boxes or object detectors. Then, the agent makes a sequence of actions $\langle a_0, \ldots, a_T \rangle$ to reach the target location, where each action is achieved by choosing a navigable node from the candidate list. The agent navigates in the environment until the target object is grounded or the agent reaches the predefined maximum trajectory length. + +# 4. Method + +As illustrated in Fig. 2, when initially situated at the starting position and given a concise high-level instruction such as "Empty the washing machine on level one", the agent first queries an LLM with the GOSP module (Sec. 4.1.1) to find out the target object "washing machine" in the instruction and reason out the potential location "laundry room" by using the world knowledge implied in an LLM. Then the ROASP module (Sec. 4.2) extracts the room type and visible objects from the current visual observation to obtain the environmental feedback. With the description of the scene perception, the LLM is queried again by the SODP (Sec. 4.1.2) to generate the next step instruction, which is used to guide the agent to navigate to the target object in the room. The baseline agent is based on + +# Target Object Recognition + +Task: + +Empty the washing machine on level one. + +Goal: + +The target object is: washing machine + +# Target Object Localization + +Example: + +Question: Where does a microwave can usually appear in a house? + +Answer: kitchen. + +Question: Where does a washing machine can usually appear in a house? + +Answer: laundry room + +(a) Prompt template of Goal-Oriented Static Planning + +# Scene-Oriented Dynamic Plan + +At this step, I am in bedroom, I can see bed, lamp, pillow. + +Example: + +Step 1: go straight and out the room + +Step 2: pass the white table + +Step 3: move into the laundry room across the hall + +Step 4: stop at the sink + +Task: Empty the washing machine on level one. Step 1: exit the bedroom + +(b) Prompt template of Scene-Oriented Dynamic Planning + +Figure 3: Examples of prompting templates for Goal-Oriented Static Planning (a) and Scene-Oriented Dynamic Planning (b). Outputs are marked with green color. And the red denotes the predicted object from Target Object Recognition. + +HM3D-DUET [10], more details can be found in the supplementary material. + +# 4.1. Planning with World Knowledge from LLMs + +This section illustrates how we utilize in-context learning (ICL) [5] to acquire world knowledge from the LLMs for planning. We first briefly introduce in-context learning. Then, we elaborate the Goal-Oriented Static Planning (GOSP) and Scene-Oriented Dynamic Planning (SODP). Last, we show the demonstration selection process. + +Preliminary: In-context Learning for Planning. In-context learning (ICL) is a paradigm that lets LLMs directly make predictions based on a natural language context without gradient updates [5]. Specifically, under the setting of in-context learning, an LLM is fed a "prompt" that usually contains a task description and several demonstrations, and then the LLM generates the required outputs. Both the prompt template and the choice of demonstration examples have an impact on how well ICL performs. In this work, we use two different ICL settings to generate different navigation plans, i.e. the GOSP and SODP module. + +The GOSP aims to identify the target object and infer the target location by arousing the world knowledge contained in an LLM through appropriate prompts. A fixed demonstration example is used for GOSP. While the SODP aims to generate step-by-step planning instructions after observing the dynamic scenes from the environment, which is more complicated than the former. To better generate plannings, we dynamically select the most suitable demonstration examples for SODP and incorporate the environmental feedback as prompts for interactive planning. + +# 4.1.1 Goal-Oriented Static Planning (GOSP) + +Given a high-level concise instruction, such as "Empty the washing machine on level one", an LLM is first asked to generate a goal-oriented static planning instruction: "Goal: + +The target object is a washing machine. It is usually in a laundry room", which emphasizes the target object and points out where the target object may lie. As shown in Fig. 3(a), the planning generation mainly consists of two sub-tasks: target object recognition and target object localization, which can be achieved by providing specifically designed prompts for the LLM. To this end, we design the prompts for the former sub-task in the form: "Task: Empty the washing machine on level one. Goal: The target object is:". Then the LLM will generate a corresponding answer: "washing machine". By contrast, the latter subtask, reasoning out the target location, is more complex because it requires more suitable prompts to arouse the internalized world knowledge in the LLM. To address this problem, we utilize a fixed demonstration example for the LLM, and design the prompts for the latter sub-task in the form: "Example: Question: Where does a microwave can usually appear in a house? Answer: kitchen. Question: Where does a washing machine can usually appear in a house? Answer: ". Given such prompts, the LLM will generate the corresponding answer "laundry room". With these answers, we can easily combine them into the goal-oriented planning format: "Goal: The target object is a washing machine. It is usually in a laundry room". + +# 4.1.2 Scene-Oriented Dynamic Planning (SODP) + +As is shown in Fig 3(b), the prompt for SODP consists of three parts. The first part is based on the scene perception of room type, such as "bedroom", and visible objects, such as "bed, lamp, pillow", obtained by the Room-and-Object Aware Scene Perceiver (ROASP, Sec. 4.2). These information are transformed into a natural language description of the current scene in the format of "At this step, I am in bedroom, I can see bed, lamp, pillow". The second part is a demonstration of the fine-grained step-by-step instruction, which is selected according to the strategy + +# R2R + +Go up the stairs and then walk the length of the couch. Walk past the dining area and into the kitchen. Stop in front of the refrigerator. + +# FGR2R + +Step 1: go up the stair +Step 2: and then walk the length of the couch +Step 3: walk past the dining area and into the kitchen +Step 4: stop in front of the refrigerator + +Figure 4: Example of instructions in R2R and FGR2R. + +detailed in the next section. The last part is previous instructions, such as "Task: Empty the washing machine on level one. Step 1:". All these three parts are concatenated together and then fed into an LLM to generate the fine-grained planning instruction for the next step accordingly, such as "Exit the bedroom". + +# 4.1.3 Dynamic Demonstration Selection + +Recent works show that providing various demonstration examples to LLMs benefits the in-context learning for different tasks [17, 22, 25]. In light of these findings, to direct the LLMs in generating better fine-grained plannings, we dynamically select the most suitable demonstration example for each specific task in REVERIE as the prompt to generate the environment-aware instruction, contrary to using a single fixed demonstration for all tasks. + +Specifically, we choose the training set of the Fine-Grained R2R dataset (FGR2R) [15] as the demonstration set $\mathcal{D}$ , of which each sample will be used as a demonstration example $D_{step}$ . As shown in Fig. 4, FGR2R decomposes each low-level instruction $I_{low}$ of R2R dataset [4] into step-by-step instructions $I_{step}$ . Then, given a high-level instruction $I_{high}$ of REVERIE, a proper $I_{low}$ will be selected as the demonstration example $D_{step}$ by a matching algorithm. In particular, we use $I_{high}$ as query $Q$ and each low-level instruction $I_{low}$ as the key $K_i$ , both of which are embedded by the Sentence-BERT [32]. The semantic distance score between the two embeddings is calculated by the cosine similarity: + +$$ +\mathrm {s} (Q, K _ {i}) = \frac {e (Q) \cdot e (K _ {i})}{\| e (Q) \| \| e (K _ {i}) \|}, \tag {1} +$$ + +where $e(\cdot)$ is the embedding function. If $K_{i}$ has the highest similarity score to the given query $Q$ , its corresponding step-by-step instruction $I_{step}$ will be selected as the demonstration example $D_{step}$ for the given high-level instruction $I_{high}$ . + +# 4.2. Room-and-Object Aware Scene Perceiver + +Though the world knowledge acquired from the static LLMs planner could benefit the embodied task promisingly, the static LLMs planner may generate wrong or irrelevant plannings, which misleads the agent. To address this issue, the LLM planner should be aware of and interact with the + +dynamic observations. In [35], the names of objects obtained from the ground truth or pre-trained detectors have been added to in-context prompts. However, the agents of these works act in a very limited space with simple scenes and monotonous objects. By contrast, REVERIE involves large-area exploration between different floors and rooms, where the scenes are more complex with more diverse objects. Considering these factors, we propose a room-and-object aware scene perceiver (ROASP) for the LLM planner, which predicts not only the room type but also the visible objects of the current location. Rather than using separate classifiers and detectors to individually predict each position's room types and visible object categories, we use CLIP [30] as the proposed room-and-object aware scene perceiver. Thanks to CLIP's strong ability of zero-shot image classification in the open world, the ROASP can well handle these two tasks. + +Specifically, we first fetch the room type labels from the MatterPort3D [6] semantic annotations and the object type labels are extracted from the REVERIE training dataset. They are used to build the codebook for the room categories $\mathbf{C}_{\mathrm{room}}$ and the object categories $\mathbf{C}_{\mathrm{obj}}$ , respectively. Then, at each timestep $t$ , the agent perceives the environment and obtains the panoramic visual observation $\mathcal{R}_t = \{r_i\}_{i=1}^n$ . For each single-view observation $r_i$ in the panorama, the image feature $f_{\mathrm{r}}$ is extracted by the CLIP Image Encoder + +$$ +f _ {\mathrm {r}} = E _ {\mathrm {C L I P}} ^ {v} \left(r _ {i}\right), \tag {2} +$$ + +where $E_{\mathrm{CLIP}}^v (\cdot)$ represents the CLIP Image Encoder. For each room category $c_{room}$ and each object category $c_{obj}$ , we respectively construct a text phrase of room $T_{\mathrm{room}}$ as "a photo of a $\{c_{room}\}$ " and a text phrase of object $T_{\mathrm{obj}}$ as "a photo of a $\{c_{obj}\}$ ". Then the text feature is derived through the pretrained CLIP Text Encoder as: + +$$ +f _ {\text {r o o m}} = E _ {\text {C L I P}} ^ {t} \left(T _ {\text {r o o m}}\right), \tag {3} +$$ + +$$ +f _ {\mathrm {o b j}} = E _ {\mathrm {C L I P}} ^ {t} \left(T _ {\mathrm {o b j}}\right), \tag {4} +$$ + +where $E_{\mathrm{CLIP}}^{t}(\cdot)$ represents the CLIP Text Encoder. At last, the similarity score $S_{\mathrm{room}}$ between the image feature $f_{\mathrm{r}}$ and the text feature $f_{\mathrm{room}}$ as well as the similarity score $S_{\mathrm{obj}}$ between the image feature $f_{\mathrm{r}}$ and the text feature $f_{\mathrm{obj}}$ are respectively computed as: + +$$ +S _ {\text {r o o m}} = \operatorname {S o f t m a x} \left(f _ {\text {r o o m}} \cdot f _ {\mathrm {r}} ^ {T}\right), \tag {5} +$$ + +$$ +S _ {\mathrm {o b j}} = \operatorname {S o f t m a x} \left(f _ {\mathrm {o b j}} \cdot f _ {\mathrm {r}} ^ {T}\right). \tag {6} +$$ + +Considering that the current environment normally belongs to only one type of room, though the panoramic images have multiple views, the room that the agent is currently centered in should have the largest influence on each view. Thus, we average the predicted room type scores $S_{\mathrm{room}}$ from multiple views and choose the room type with + +
HLIEmpty the washing machine on level one.
GOSPGoal: The target object is washing machine. It is usually in laundry room.
SODPStep 1: exit the bedroom +Step 2: go down the stairs +...
+ +Figure 5: Text inputs contains three parts: High-level Instruction in REVERIE (HLI), Goal-Oriented Static Planning (GOSP) and Scene-Oriented Dynamic Planning (SODP) returned instructions. + +the greatest score as the room type prediction $\hat{c}_{\mathrm{room}}$ . For object predictions, if the object occupies more proportion in a view, the matching score $S_{\mathrm{obj}}$ should be higher. Thus, we select $k$ prominent objects with the top- $k$ matching scores as the auxiliary environment feedback in addition to the predicted room. + +# 4.3. March with Interactive Prompting + +When the generation of the goal-oriented planning and the scene-oriented planning with perceptions from the environment is finished, the agent can march towards the target object at each timestep $t$ under the guidance of the interactive prompting. In this section, we will give a detailed description of how the interactive prompting works during the process of navigation, which mainly consists of two parts, i.e. the assembled instruction and the instruction update. + +Assembled Instruction At each timestep $t$ , the agent observes the environment and receives the assembled instructions obtained from the above-mentioned modules, and choose an action to perform. Specifically, as shown in Fig. 5, the assembled instructions $W$ of the interactive prompting mainly consist of three parts: the high-level instruction (HLI) $W_{I}$ in REVERIE, the GOSP instruction $W_{G}$ and the SODP instruction $W_{S}$ . We concatenate these three parts of instructions as the assembled instruction $W = [W_{I}, W_{G}, W_{S}]$ and use WordPieces [20] to tokenize all the words into a sequence of tokens as the textual input for the agent. Then, the agent will act under the guidance of such assembled instruction. Note that the use of the original high-level instruction $W_{I}$ can improve the model's tolerance on the noise of intermediate planning instructions. + +Instruction Update The GOSP is only conducted once at the beginning of the task. While the SODP is conducted depending on the feedback of environments. Specifically, at each timestep $t$ , if the ROASP finds the room has changed where the predicted room $\hat{c}_{\mathrm{room}}^t$ does not equal to $\hat{c}_{\mathrm{room}}^{t-1}$ , the SODP will be triggered again. Then, a new step-by-step instruction such as "Step 2: go down the stairs" for the next few steps will be generated by the LLM and added to the previous assembled instruction $W$ after the last step-by-step + +instruction of "Step 1: exit the bedroom". Then, the agent will act under the guidance of the updated instructions $W'$ . + +# 5. Experiment + +# 5.1. Evaluation Setup + +Dataset REVERIE [27] contains 10,567 panoramic images within 90 buildings (4,140 target objects divided into 489 categories) and 21,702 instructions with 18 words on average. Each target viewpoint has 7 distinct panoramic objects with 50 bounding boxes on average. It consists of four splits: train, validation seen, validation unseen and test unseen. + +Evaluation Metrics The performance of agents is evaluated in two ways: navigation and object grounding. For the navigation sub-task, the metrics are Success Rate (SR), Oracle Success Rate (OSR), and Success weighted by Path Length [3] (SPL), where SPL is the main metric. For the grounding sub-task, the metrics are Remote Grounding Success rate (RGS) and RGS weighted by Path Length (RGSPL), where RGSPL is the main metric for this subtask. For all these metrics, higher is better. + +TL Trajectory Length measures the average length of all the predicted navigation trajectories in meters. +SR Success Rate measures the ratio of successful tasks, of which the agent's stop location is less than 3 meters away from the target location. +OSR Oracle Success Rate measures the ratio of tasks of which one of its trajectory viewpoints can observe the target object within 3 meters. +SPL Success weighted by Path Length trades-off SR (Success Rate) against TL (Trajectory Length). It measures both the accuracy and efficiency of navigation. +RGS Remote Grounding Success rate measures the ratio of tasks that successfully locate the target object. +RGSPL RGS weighted by Path Length is RGS. + +Implementation Details Our model is trained on a single 3090 GPU for 30,000 iterations. We set the batch size to 4 and the learning rate to $1 \times 10^{-5}$ . The best model is selected according to performance on the validation unseen split. We use the same pretrained model and augmented data as [10] for a fair comparison. For the LLMs, we use the public GPT-2 [31] model for in-context learning. For the scene preceptor, we keep the top 3 object predictions for each position. + +# 5.2. Comparison with State-of-The-Art Methods + +As shown in Table 1, we compare MiC with the state-of-the-art methods on the REVERIE benchmark. Our method + +
MethodsVal UnseenTest Unseen
NavigationGroundingNavigationGrounding
TLOSR↑SR↑SPL↑RGS↑RGSPL↑TLOSR↑SR↑SPL↑RGS↑RGSPL↑
Human------21.1886.8381.5153.6677.8451.44
Seq2Seq11.078.074.202.842.161.6310.896.883.993.092.001.58
RCM [37]11.9814.239.296.974.8910.607.843.8911.686.673.673.14
SMNA [23]9.0711.288.156.444.543.619.238.395.804.533.102.39
FAST-MATTN [27]45.2828.2014.407.197.844.6739.0530.6319.8811.6111.286.08
ORIST [26]10.9025.0216.8415.148.527.5811.3829.2022.1918.9710.689.28
CKR [12]26.2631.4419.1411.8411.45-22.4630.4022.0014.2511.60-
RecBERT [16]16.7835.0230.6724.9018.7715.2715.8632.9129.6123.9916.5013.51
Airbert [13]18.7134.5127.8921.8818.2314.1817.9134.2030.2823.6116.8313.28
HAMT [9]14.0836.8432.9530.2018.9217.2813.6233.4130.4026.6714.8812.08
HOP [28]16.4636.2431.7826.1118.8515.7316.3833.0630.1724.3417.6914.34
TD-STP [38]-39.4834.8827.3221.1616.56-40.2635.8927.5119.8815.40
DUET [11]22.1151.0746.9833.7332.1523.0321.3056.9152.5136.0631.8822.06
HM3D-DUET [10]-62.1455.8940.8536.5826.76-62.3055.1738.8832.2322.68
MiC20.6462.3756.9743.6037.5228.7218.1162.4055.7441.9735.2526.17
+ +Table 1: Comparison with the state-of-the-art methods on REVERIE. + +
ComponentsNavigationGrounding
OSR↑SR↑SPL↑RGS↑RGSPL↑
HLI(Baseline)58.0252.7140.4934.9326.82
HLI+GOSP59.9255.2842.4637.1328.24
HLI+SODP60.7256.2642.9436.8027.81
HLI+GOSP+SODP62.3756.9743.6037.5228.72
+ +outperforms previous methods in all metrics on both validation unseen and test unseen splits. Particularly, compared with the SoTA method HM3D-DUET [10], MiC outperforms HM3D-DUET by a large margin of $3.09\%$ in terms of the main navigation metric SPL and $3.49\%$ of the main object grounding metric RGSPL on the Test Unseen split. Note that MiC shares the same pre-trained model with the HM3D-DUET, these promising result demonstrates that our method can effectively improve the navigation and object grounding ability of agents. + +# 5.3. Ablation Analysis + +Contribution of different MiC Components In Table 2, we evaluate the effect of different components in our proposed MiC. HLI denotes only using the original high-level instruction (HLI) provided by REVERIE. + +Compared to the baseline HLI, GOSP improves the performance of both navigation $(2.57\% \uparrow$ on SR, $1.97\% \uparrow$ on SPL) and object grounding $(2.20\% \uparrow$ on RGS, $1.42\% \uparrow$ on RGSPL) with a non-trivial margin, showing the effectiveness of the proposed goal-oriented static planning. SODP further surpasses GOSP in the navigation metric $(0.98\% \uparrow$ on SR, $0.48\% \uparrow$ on SPL) while falling a little behind in the grounding metrics $(0.33\% \uparrow$ on RGS, $1.43\% \uparrow$ on RGSPL). The reason may be that the detailed step-by-step planning occupies a large proportion compared to the target object + +Table 2: Ablation of different components in MiC. + +
MethodsNavigationGrounding
OSR↑SR↑SPL↑RGS↑RGSPL↑
Baseline58.0252.7140.4934.9326.82
Static60.2455.3541.7436.3027.03
Dynamic60.7256.2642.9436.8027.81
+ +Table 3: Comparison of different plan generation settings. + +
MethodsRelevancyRationality
Scene-Oriented Dynamic Planning2.061.93
- w/o Dynamic Demonstration1.411.23
- w/o ROASP1.641.55
+ +Table 4: Human study of the prompt setting for Scene-Oriented Dynamic Planning. + +in the input texts, which can bring the noise for object grounding while improving navigation performance. When combining all these components, the final performance gets further increased in all metrics, which surpasses the baseline with a large margin (4.26%↑ on SR, 3.11%↑ on SPL, 2.59%↑ on RGS and 1.9%↑ on RGSPL). The promising results here show that these components are complementary to each other. + +The Effect of the ROASP To evaluate the effectiveness of ROASP used for the scene-oriented dynamic planning, we conduct another ablation study via whether incorporating the feedback from the ROASP module on REVERIE validation unseen set. We report results in three settings: (I) Baseline: The input assembled instruction only contains the given high-level instruction in REVERIE. (II) Static: The input assembled instruction contains the REVERIE and fine-grained static instructions. The difference between + +
REVERIE Instruction: Go to the bathroom with the two towels and empty the lower cabinet.
Scene-Oriented Dynamic Planningw/o Dynamic Demonstrationw/o ROASP
Step 1: exit the bedroomStep 1: put the towel in the bottom drawer of the toiletStep 1: exit the bathroom
Step 2: and walk into the next bedroom in the hallStep 2: walk into the kitchen
Step 3: go stand in the kitchen doorway
Step 3: go stand in the bathroomStep 4: go back to the bedroom and take the towel
Step 5: exit the bedroom
Step 6: walk into the next bedroom in the hall
REVERIE Instruction: Go to the kitchen on level 2 and open the drawer.
Scene-Oriented Dynamic Planningw/o Dynamic Demonstrationw/o ROASP
Step 1: go upstairsStep 1: open the drawer with the key in itStep 1: go upstairs and turn left at the hall
Step 2: go straight pass the couchStep 2: remove the lock from the doorStep 2: go back down the stairs
Step 3: make a slight left towards the refrigeratorStep 3: then turn onStep 3: go up the stairs again
Step 4: wait near the kitchen drawerStep 4: go back to the kitchen and open the fridge
Step 5: take out the fruit and put it in the juicer
+ +Figure 6: Examples of generated instructions. + +fine-grained static instruction and scene-oriented dynamic instruction is that static fine-grained instruction is generated without ROASP. More specifically, the query prompt for the LLM to generate step-by-step planning is fixed at each timestep, which only consists of the given high-level instruction and the selected demonstration. (III) Dynamic: The input assembled instruction contains the high-level instruction in REVERIE and scene-oriented dynamic planning instruction. As shown in Table 3, in the static setting, the performance in all metrics is improved compared to the baseline, indicating the effectiveness of the LLM's rich world knowledge in fine-grained planning. In the dynamic setting, the performance is further improved with non-trivial margins, showing the effectiveness of ROASP. + +Qualitative Analysis of Prompt Setting To further evaluate the effect of dynamic demonstration and ROASP in SODP, we perform a human evaluation about the generated plannings (see Table 4) and show the planning results (see Fig. 6). For human evaluation, we randomly selected 100 REVERIE tasks and generate fine-grained step-by-step instructions in setting of SODP, SODP without dynamic demonstration, and SODP without ROASP. We asked 10 volunteers to mark the generated step-by-step instructions in terms of their relevancy and rationality. The relevancy score ranges from 0 (unrelated) to 3 (very related), which takes into account whether the keywords in instructions are related to the REVERIE task. For example, regarding the REVERIE instruction "Go to the kitchen and turn on the microwave", whether there are keywords in instructions related to the kitchen scene could be rated. Rationality is rated from 0 (bad) to 3 (perfect), considering whether the instruction conforms to the logic of navigation. + +The results are presented in Table 4. It shows that our SODP scored 2.06 on Relevancy and 1.93 on Rational- + +ity, which could be considered acceptable since the highest score is 3 and it is challenging to generate instructions that are consistent with tasks and actual navigation logic. When removing the dynamic demonstration, the score of generated instruction drops about $31.55\%$ on Relevancy and $36.27\%$ on Rationality, which could also be observed in Fig. 6. Although the instruction generated without dynamic demonstration is related to the task to some extent (e.g., "put the towel in the bottom drawer of the toilet" has the keyword "towel", the instruction lacks navigation information, such as how to reach the bathroom.) As shown in the bottom example of Fig. 6, instruction without ROASP successfully guided how to go to the destination location kitchen, but it still caused confusion by going upstairs and going downstairs several times, and thus reducing the rationality score, i.e. 1.64 on Relevancy and 1.55 on Rationality. More generation results can be found in the supplementary. + +# 6. Conclusions + +In this work, we propose a novel model, March-in-Chat (MiC), for the REVEIRE task, which only provides concise high-level instructions for the VLN agent. MiC enables the REVERIE agent to talk with an LLM on the fly to generate plans for the next few steps. It consists of three main modules, Goal-Oriented Static Planning (GOSP), Scene-Oriented Dynamic Planning (SODP), and Room-and-Object Aware Scene Perceiver (ROASP) module. We conduct extensive quantitative and qualitative experiments on REVERIE and the promising results show the effectiveness of our method. + +# 7. Acknowledgements + +Jing Liu is supported by the National Key Research and Development Program of China (No. 2020AAA0106400). + +# References + +[1] Michael Ahn, Anthony Brohan, Noah Brown, Yevgen Chebotar, Omar Cortes, Byron David, Chelsea Finn, Chuyuan Fu, Keerthana Gopalakrishnan, Karol Hausman, Alex Herzog, Daniel Ho, Jasmine Hsu, Julian Ibarz, Brian Ichter, Alex Irpan, Eric Jang, Rosario Jauregui Ruano, Kyle Jeffrey, Sally Jesmonth, Nikhil Joshi, Ryan Julian, Dmitry Kalashnikov, Yuheng Kuang, Kuang-Huei Lee, Sergey Levine, Yao Lu, Linda Luu, Carolina Parada, Peter Pastor, Jornell Quiambao, Kanishka Rao, Jarek Rettinghouse, Diego Reyes, Pierre Sermanet, Nicolas Sievers, Clayton Tan, Alexander Toshev, Vincent Vanhoucke, Fei Xia, Ted Xiao, Peng Xu, Sichun Xu, Mengyuan Yan, and Andy Zeng. Do as i can and not as i say: Grounding language in robotic affordances. In arXiv preprint arXiv:2204.01691, 2022. 3 +[2] Dong An, Yuankai Qi, Yangguang Li, Yan Huang, Liang Wang, Tieniu Tan, and Jing Shao. Bevbert: Topo-metric map pre-training for language-guided navigation. arXiv preprint arXiv:2212.04385, 2022. 2 +[3] Peter Anderson, Angel X. Chang, Devendra Singh Chaplot, Alexey Dosovitskiy, Saurabh Gupta, Vladlen Koltun, Jana Kosecka, Jitendra Malik, Roozbeh Mottaghi, Manolis Savva, and Amir Roshan Zamir. On evaluation of embodied navigation agents. CoRR, abs/1807.06757, 2018. 6 +[4] Peter Anderson, Qi Wu, Damien Teney, Jake Bruce, Mark Johnson, Niko Sünderhauf, Ian D. Reid, Stephen Gould, and Anton van den Hengel. Vision-and-language navigation: Interpreting visually-grounded navigation instructions in real environments. In CVPR, pages 3674-3683, 2018. 1, 2, 5 +[5] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, Sandhini Agarwal, Ariel Herbert-Voss, Gretchen Krueger, Tom Henighan, Rewon Child, Aditya Ramesh, Daniel Ziegler, Jeffrey Wu, Clemens Winter, Chris Hesse, Mark Chen, Eric Sigler, Mateusz Litwin, Scott Gray, Benjamin Chess, Jack Clark, Christopher Berner, Sam McCandlish, Alec Radford, Ilya Sutskever, and Dario Amodei. Language models are few-shot learners. In NeurIPS, pages 1877-1901, 2020. 3, 4 +[6] Angel X. Chang, Angela Dai, Thomas A. Funkhouser, Macej Halber, Matthias Nießner, Manolis Savva, Shuran Song, Andy Zeng, and Yinda Zhang. Matterport3d: Learning from RGB-D data in indoor environments. In 3DV, pages 667-676, 2017. 5 +[7] Howard Chen, Alane Suhr, Dipendra Misra, Noah Snavely, and Yoav Artzi. TOUCHDOWN: natural language navigation and spatial reasoning in visual street environments. In CVPR, pages 12538-12547, 2019. 1, 2 +[8] Mark Chen, Jerry Tworek, Heewoo Jun, Qiming Yuan, Henrique Ponde de Oliveira Pinto, Jared Kaplan, Harri Edwards, Yuri Burda, Nicholas Joseph, Greg Brockman, et al. Evaluating large language models trained on code. arXiv preprint arXiv:2107.03374, 2021. 3 +[9] Shizhe Chen, Pierre-Louis Guhur, Cordelia Schmid, and Ivan Laptev. History aware multimodal transformer for vision-and-language navigation. In NeurIPS, pages 5834-5847, 2021. 7 + +[10] Shizhe Chen, Pierre-Louis Guhur, Makarand Tapaswi, Cordelia Schmid, and Ivan Laptev. Learning from unlabeled 3d environments for vision-and-language navigation. In ECCV, 2022. 4, 6, 7 +[11] Shizhe Chen, Pierre-Louis Guhur, Makarand Tapaswi, Cordelia Schmid, and Ivan Laptev. Think global, act local: Dual-scale graph transformer for vision-and-language navigation. In CVPR, 2022. 2, 7 +[12] Chen Gao, Jinyu Chen, Si Liu, Luting Wang, Qiong Zhang, and Qi Wu. Room-and-object aware knowledge reasoning for remote embodied referring expression. In CVPR, pages 3064-3073, 2021. 7 +[13] Pierre-Louis Guhur, Makarand Tapaswi, Shizhe Chen, Ivan Laptev, and Cordelia Schmid. Airbert: In-domain pretraining for vision-and-language navigation. In ICCV, pages 1634-1643, 2021. 7 +[14] Keji He, Yan Huang, Qi Wu, Jianhua Yang, Dong An, Shuanglin Sima, and Liang Wang. Landmark-rxr: Solving vision-and-language navigation with fine-grained alignment supervision. NeurIPS, 34:652-663, 2021. 2 +[15] Yicong Hong, Cristian Rodriguez Opazo, Qi Wu, and Stephen Gould. Sub-instruction aware vision-and-language navigation. In Bonnie Webber, Trevor Cohn, Yulan He, and Yang Liu, editors, EMNLP, pages 3360-3376, 2020. 5 +[16] Yicong Hong, Qi Wu, Yuankai Qi, Cristian Rodriguez Opazo, and Stephen Gould. VLN $\text{©}$ BERT: A recurrent vision-and-language BERT for navigation. In CVPR, pages 1643-1653, 2021. 2, 7 +[17] Wenlong Huang, Pieter Abbeel, Deepak Pathak, and Igor Mordatch. Language models as zero-shot planners: Extracting actionable knowledge for embodied agents. In ICML, pages 9118-9147. PMLR, 2022. 2, 3, 5 +[18] Wenlong Huang, Fei Xia, Ted Xiao, Harris Chan, Jacky Liang, Pete Florence, Andy Zeng, Jonathan Tompson, Igor Mordatch, Yevgen Chebotar, Pierre Sermanet, Noah Brown, Tomas Jackson, Linda Luu, Sergey Levine, Karol Hausman, and Brian Ichter. Inner monologue: Embodied reasoning through planning with language models. In arXiv preprint arXiv:2207.05608, 2022. 3 +[19] Vihan Jain, Gabriel Magalhães, Alexander Ku, Ashish Vaswani, Eugene Ie, and Jason Baldridge. Stay on the path: Instruction fidelity in vision-and-language navigation. pages 1862-1872, 2019. 2 +[20] Melvin Johnson, Mike Schuster, Quoc V. Le, Maxim Krikun, Yonghui Wu, Zhifeng Chen, Nikhil Thorat, Fernanda B. Viégas, Martin Wattenberg, Greg Corrado, Macduff Hughes, and Jeffrey Dean. Google's multilingual neural machine translation system: Enabling zero-shot translation. Trans. Assoc. Comput. Linguistics, 5:339-351, 2017. 6 +[21] Alexander Ku, Peter Anderson, Roma Patel, Eugene Ie, and Jason Baldridge. Room-across-room: Multilingual vision-and-language navigation with dense spatiotemporal grounding. In EMNLP, pages 4392-4412, 2020. 1, 2 +[22] Jiachang Liu, Dinghan Shen, Yizhe Zhang, Bill Dolan, Lawrence Carin, and Weizhu Chen. What makes good in-context examples for gpt-3? arXiv preprint arXiv:2101.06804, 2021. 5 + +[23] Chih-Yao Ma, Jiasen Lu, Zuxuan Wu, Ghassan AlRegib, Zsolt Kira, Richard Socher, and Caiming Xiong. Self-monitoring navigation agent via auxiliary progress estimation. In ICLR, 2019. 7 +[24] Khanh Nguyen and Hal Daumé III. Help, anna! visual navigation with natural multimodal assistance via retrospective curiosity-encouraging imitation learning. pages 684–695. Association for Computational Linguistics, 2019. 2 +[25] Gabriel Poesia, Alex Polozov, Vu Le, Ashish Tiwari, Gustavo Soares, Christopher Meek, and Sumit Gulwani. Synchromesh: Reliable code generation from pre-trained language models. In ICLR, 2022. 5 +[26] Yuankai Qi, Zizheng Pan, Yicong Hong, Ming-Hsuan Yang, Anton van den Hengel, and Qi Wu. The road to knowwhere: An object-and-room informed sequential bert for indoor vision-language navigation. In ICCV, pages 1655-1664, 2021. 2, 7 +[27] Yuankai Qi, Qi Wu, Peter Anderson, Xin Wang, William Yang Wang, Chunhua Shen, and Anton van den Hengel. REVERIE: remote embodied visual referring expression in real indoor environments. In CVPR, pages 9979-9988, 2020. 1, 2, 6, 7 +[28] Yanyuan Qiao, Yuankai Qi, Yicong Hong, Zheng Yu, Peng Wang, and Qi Wu. HOP: history-and-order aware pretraining for vision-and-language navigation. In CVPR, pages 15397-15406, 2022. 2, 7 +[29] Yanyuan Qiao, Yuankai Qi, Yicong Hong, Zheng Yu, Peng Wang, and Qi Wu. Hop+: History-enhanced and order-aware pre-training for vision-and-language navigation. IEEE TPAMI, 2023. 2 +[30] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, Gretchen Krueger, and Ilya Sutskever. Learning transferable visual models from natural language supervision. In ICML, volume 139, pages 8748-8763, 2021. 5 +[31] Alec Radford, Jeffrey Wu, Rewon Child, David Luan, Dario Amodei, Ilya Sutskever, et al. Language models are unsupervised multitask learners. OpenAI blog, 1(8):9, 2019. 3, 6 +[32] Nils Reimers and Iryna Gurevych. Sentence-bert: Sentence embeddings using siamese bert-networks. In Kentaro Inui, Jing Jiang, Vincent Ng, and Xiaojun Wan, editors, EMNLP-IJCNLP, pages 3980-3990, 2019. 5 +[33] Mohit Shridhar, Jesse Thomason, Daniel Gordon, Yonatan Bisk, Winson Han, Roozbeh Mottaghi, Luke Zettlemoyer, and Dieter Fox. ALFRED: A benchmark for interpreting grounded instructions for everyday tasks. In CVPR, pages 10737-10746, 2020. 1, 3 +[34] Ishika Singh, Valts Blukis, Arsalan Mousavian, Ankit Goyal, Danfei Xu, Jonathan Tremblay, Dieter Fox, Jesse Thomason, and Animesh Garg. ProgPrompt: Generating situated robot task plans using large language models. 2022. 2 +[35] Chan Hee Song, Jiaman Wu, Clayton Washington, Brian M Sadler, Wei-Lun Chao, and Yu Su. Llm-planner: Few-shot grounded planning for embodied agents with large language models. arXiv preprint arXiv:2212.04088, 2022. 3, 5 + +[36] Jesse Thomason, Michael Murray, Maya Cakmak, and Luke Zettlemoyer. Vision-and-dialog navigation. In CoRL, pages 394-406, 2019. 1, 2 +[37] Xin Wang, Qiuyuan Huang, Asli Celikyilmaz, Jianfeng Gao, Dinghan Shen, Yuan-Fang Wang, William Yang Wang, and Lei Zhang. Reinforced cross-modal matching and self-supervised imitation learning for vision-language navigation. In CVPR, pages 6629-6638, 2019. 7 +[38] Yusheng Zhao, Jinyu Chen, Chen Gao, Wenguan Wang, Lirong Yang, Haibing Ren, Huaxia Xia, and Si Liu. Target-driven structured transformer planner for vision-language navigation. pages 4194-4203, 2022. 7 +[39] Fengda Zhu, Xiwen Liang, Yi Zhu, Qizhi Yu, Xiaojun Chang, and Xiaodan Liang. SOON: scenario oriented object navigation with graph-based exploration. In CVPR, pages 12689-12699, 2021. 1, 2 \ No newline at end of file diff --git a/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/images.zip b/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..34cc859d908b34659f70f759cc59cb879cf520d3 --- /dev/null +++ b/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:f1c71e3333edc3167f5fd7306b32d09b7b5f97d1e368c547d55723037bdf0c30 +size 373820 diff --git a/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/layout.json b/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..98464b68a4f1083f96ebdfcb1e2abd7120910887 --- /dev/null +++ b/2023/March in Chat_ Interactive Prompting for Remote Embodied Referring Expression/layout.json @@ -0,0 +1,8676 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 162, + 136, + 416, + 170 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 162, + 136, + 416, + 170 + ], + "spans": [ + { + "bbox": [ + 162, + 136, + 416, + 170 + ], + "type": "text", + "content": "March in Chat: Interactive Prompting for Remote Embodied Referring Expression" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 126, + 191, + 454, + 207 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 126, + 191, + 454, + 207 + ], + "spans": [ + { + "bbox": [ + 126, + 191, + 454, + 207 + ], + "type": "text", + "content": "Yanyuan Qiao" + }, + { + "bbox": [ + 126, + 191, + 454, + 207 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 126, + 191, + 454, + 207 + ], + "type": "text", + "content": " Yuankai Qi" + }, + { + "bbox": [ + 126, + 191, + 454, + 207 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 126, + 191, + 454, + 207 + ], + "type": "text", + "content": " Zheng Yu" + }, + { + "bbox": [ + 126, + 191, + 454, + 207 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 126, + 191, + 454, + 207 + ], + "type": "text", + "content": " Jing Liu" + }, + { + "bbox": [ + 126, + 191, + 454, + 207 + ], + "type": "inline_equation", + "content": "^{2,3}" + }, + { + "bbox": [ + 126, + 191, + 454, + 207 + ], + "type": "text", + "content": " Qi Wu" + }, + { + "bbox": [ + 126, + 191, + 454, + 207 + ], + "type": "inline_equation", + "content": "^{1*}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 123, + 207, + 455, + 220 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 123, + 207, + 455, + 220 + ], + "spans": [ + { + "bbox": [ + 123, + 207, + 455, + 220 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 123, + 207, + 455, + 220 + ], + "type": "text", + "content": "Australian Institute for Machine Learning, The University of Adelaide" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 157, + 220, + 420, + 233 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 157, + 220, + 420, + 233 + ], + "spans": [ + { + "bbox": [ + 157, + 220, + 420, + 233 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 157, + 220, + 420, + 233 + ], + "type": "text", + "content": "Institute of Automation, Chinese Academy of Sciences" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 110, + 233, + 475, + 247 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 233, + 475, + 247 + ], + "spans": [ + { + "bbox": [ + 110, + 233, + 475, + 247 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 110, + 233, + 475, + 247 + ], + "type": "text", + "content": "School of Artificial Intelligence, University of Chinese Academy of Sciences" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 68, + 249, + 508, + 261 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 249, + 508, + 261 + ], + "spans": [ + { + "bbox": [ + 68, + 249, + 508, + 261 + ], + "type": "text", + "content": "{yanyuan.qiao,zheng.yu,qi.wu01}@adelaide.edu.au, qykshr@gmail.com,jliu@nlpr.ia.ac.cn" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 139, + 287, + 186, + 299 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 139, + 287, + 186, + 299 + ], + "spans": [ + { + "bbox": [ + 139, + 287, + 186, + 299 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 45, + 313, + 282, + 581 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 313, + 282, + 581 + ], + "spans": [ + { + "bbox": [ + 45, + 313, + 282, + 581 + ], + "type": "text", + "content": "Many Vision-and-Language Navigation (VLN) tasks have been proposed in recent years, from room-based to object-based and indoor to outdoor. The REVERIE (Remote Embodied Referring Expression) is interesting since it only provides high-level instructions to the agent, which are closer to human commands in practice. Nevertheless, this poses more challenges than other VLN tasks since it requires agents to infer a navigation plan only based on a short instruction. Large Language Models (LLMs) show great potential in robot action planning by providing proper prompts. Still, this strategy has not been explored under the REVERIE settings. There are several new challenges. For example, the LLM should be environment-aware so that the navigation plan can be adjusted based on the current visual observation. Moreover, the LLM planned actions should be adaptable to the much larger and more complex REVERIE environment. This paper proposes a March-in-Chat (MiC) model that can talk to the LLM on the fly and plan dynamically based on a newly proposed Room-and-Object Aware Scene Perceiver (ROASP). Our MiC model outperforms the previous state-of-the-art by large margins by SPL and RGSPL metrics on the REVERIE benchmark. The source code is available at https://github.com/YanyuanQiao/MiC" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 606, + 124, + 618 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 606, + 124, + 618 + ], + "spans": [ + { + "bbox": [ + 46, + 606, + 124, + 618 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 45, + 626, + 279, + 708 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 626, + 279, + 708 + ], + "spans": [ + { + "bbox": [ + 45, + 626, + 279, + 708 + ], + "type": "text", + "content": "Vision-and-Language Navigation (VLN), which lies at the intersection of computer vision, natural language processing and robotics, has aroused great attention from research communities in the past few years. Given instructions in natural language, the VLN agent should navigate to the target location based on the dynamic observations in the 3D simulated environments. Since VLN has great" + } + ] + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 309, + 312, + 516, + 433 + ], + "blocks": [ + { + "bbox": [ + 305, + 291, + 516, + 310 + ], + "lines": [ + { + "bbox": [ + 305, + 291, + 516, + 310 + ], + "spans": [ + { + "bbox": [ + 305, + 291, + 516, + 310 + ], + "type": "text", + "content": "REVERIE Instruction: Clean the small picture in front of the large mirror." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 309, + 312, + 516, + 433 + ], + "lines": [ + { + "bbox": [ + 309, + 312, + 516, + 433 + ], + "spans": [ + { + "bbox": [ + 309, + 312, + 516, + 433 + ], + "type": "image", + "image_path": "8f6ac22cb1ca7ce66006da99c22e278d7607c56e42a86de54ec831bc88a4072c.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 296, + 442, + 531, + 490 + ], + "lines": [ + { + "bbox": [ + 296, + 442, + 531, + 490 + ], + "spans": [ + { + "bbox": [ + 296, + 442, + 531, + 490 + ], + "type": "text", + "content": "Figure 1: Our March-in-Chat (MiC) model is talking to a Large Language Model (LLM) to generate navigation plans on the fly, with the REVERIE instruction and the dynamic room-and-object information as inputs." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "bbox": [ + 296, + 496, + 530, + 624 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 496, + 530, + 624 + ], + "spans": [ + { + "bbox": [ + 296, + 496, + 530, + 624 + ], + "type": "text", + "content": "potential in real-world applications such as domestic assistant robots, a large amount of specific VLN tasks have been proposed, including R2R [4] and RxR [21] that ask the agent to navigate from one room to another in a photorealistic environment according to the fine-grained instruction, NDH [36] provides detailed dialogues which imply the instruction, TouchDown [7] extends the task into an outdoor environment, REVERIE [27] and SOON [39] that additionally require the agent's ability of remote object grounding and ALFRED [33] that asks the agent to interact with the target object in a single room of the synthetic environment." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 296, + 624, + 531, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 624, + 531, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 624, + 531, + 730 + ], + "type": "text", + "content": "Most of these VLN tasks provide detailed step-by-step instructions to the agent, such as \"Go up the stairs and then walk the length of the couch. Walk past the dining area and into the kitchen. Stop in front of the refrigerator.\" in R2R. Although detailed instructions can help the agent better achieve the navigation goal in the simulated environments, it has a big gap towards real applications where human beings tend to give coarse-grained high-level instructions such as \"Go to the refrigerator on the second floor\"." + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 77, + 42, + 119, + 72 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 77, + 42, + 119, + 72 + ], + "spans": [ + { + "bbox": [ + 77, + 42, + 119, + 72 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 151, + 41, + 470, + 73 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 151, + 41, + 470, + 73 + ], + "spans": [ + { + "bbox": [ + 151, + 41, + 470, + 73 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 57, + 719, + 131, + 730 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 719, + 131, + 730 + ], + "spans": [ + { + "bbox": [ + 57, + 719, + 131, + 730 + ], + "type": "text", + "content": "*Corresponding author" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 277, + 746, + 301, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 746, + 301, + 756 + ], + "spans": [ + { + "bbox": [ + 277, + 746, + 301, + 756 + ], + "type": "text", + "content": "15758" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 45, + 106, + 279, + 212 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 106, + 279, + 212 + ], + "spans": [ + { + "bbox": [ + 45, + 106, + 279, + 212 + ], + "type": "text", + "content": "Contrary to other tasks, the Remote Embodied Referring Expression (REVERIE) task is more likely to empower the real-world applications of VLN, of which the instructions are closer to those in practice, such as \"Empty the washing machine on level one\". Such high-level instruction is more challenging for VLN agents since it requires them to be more competent in perceiving the surrounding environment and the navigation progress and correspondingly making reasonable plans for the next steps." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 45, + 213, + 280, + 341 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 213, + 280, + 341 + ], + "spans": [ + { + "bbox": [ + 45, + 213, + 280, + 341 + ], + "type": "text", + "content": "Recently, Large Language Models (LLMs) that internalize a wealth of commonsense knowledge show great potential in action planning for some embodied tasks with the help of suitable in-context learning. However, previous works mainly utilize LLMs to plan atomic actions of object manipulation in a very limited space with simple scenes. These predefined atomic actions can be easily planned well by the LLMs planners with a unified template. Different from these embodied tasks, REVERIE requires large-area exploration from one room to another, which is complex in the layout of rooms and scenes with diverse objects." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 45, + 343, + 280, + 588 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 343, + 280, + 588 + ], + "spans": [ + { + "bbox": [ + 45, + 343, + 280, + 588 + ], + "type": "text", + "content": "In this work, to adapt LLMs as the planner for REVERIE with the ability of comprehensive scene perception, we propose a novel model named March in Chat (MiC), which enables the LLM as an environment-aware instruction planner through on-the-fly dialogues between the agent and the LLM as Fig. 1 shows. Specifically, the agent is initially situated at the starting position given a high-level coarse-grained REVERIE instruction. First, a Goal-Oriented Static Planning (GOSP) module queries the LLM to point out the target object and infer where the thing may be by using the rich world knowledge internalized in the LLM. Secondly, the agent's Room-and-Object Aware Scene Perceiver (ROASP) describes the current observation and asks the LLM to generate step-by-step fine-grained planning for the next navigation steps. Then, if the ROASP finds the room has changed, the LLM is queried again by the Scene-Oriented Dynamic Planning (SODP) module to generate a new fine-grained step-by-step planning, which will be concatenated with all previous responses from the LLM. The agent will march under the guidance of such interactive prompting until the task is finished." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 590, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 590, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 590, + 279, + 730 + ], + "type": "text", + "content": "To evaluate our proposed MiC, we conduct experiments on the REVERIE benchmark. Our MiC achieves a new state-of-the-art performance in all metrics on REVERIE val unseen set and REVERIE test unseen set. Mainly, MiC obtains " + }, + { + "bbox": [ + 45, + 590, + 279, + 730 + ], + "type": "inline_equation", + "content": "41.97\\%" + }, + { + "bbox": [ + 45, + 590, + 279, + 730 + ], + "type": "text", + "content": " on the primary navigation metric of SPL and " + }, + { + "bbox": [ + 45, + 590, + 279, + 730 + ], + "type": "inline_equation", + "content": "26.17\\%" + }, + { + "bbox": [ + 45, + 590, + 279, + 730 + ], + "type": "text", + "content": " on the major object grounding metric of RGSPL on test split, which is at least " + }, + { + "bbox": [ + 45, + 590, + 279, + 730 + ], + "type": "inline_equation", + "content": "3.09\\%" + }, + { + "bbox": [ + 45, + 590, + 279, + 730 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 45, + 590, + 279, + 730 + ], + "type": "inline_equation", + "content": "3.49\\%" + }, + { + "bbox": [ + 45, + 590, + 279, + 730 + ], + "type": "text", + "content": " higher than the previous SoTA results. We also conduct ablation studies to validate the contributions of different components in MiC and the effect of scene-aware perception in dynamic planning generation. These promising results demonstrate the effectiveness of our proposed MiC." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 308, + 106, + 508, + 117 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 106, + 508, + 117 + ], + "spans": [ + { + "bbox": [ + 308, + 106, + 508, + 117 + ], + "type": "text", + "content": "In summary, we make the following contributions:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 308, + 117, + 530, + 246 + ], + "type": "list", + "angle": 0, + "index": 8, + "blocks": [ + { + "bbox": [ + 308, + 117, + 530, + 152 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 117, + 530, + 152 + ], + "spans": [ + { + "bbox": [ + 308, + 117, + 530, + 152 + ], + "type": "text", + "content": "- We propose a novel March-in-Chat (MiC) model, which lets the REVERIE agent talk with an LLM on the fly to make plans for the next few steps." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 308, + 154, + 530, + 212 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 154, + 530, + 212 + ], + "spans": [ + { + "bbox": [ + 308, + 154, + 530, + 212 + ], + "type": "text", + "content": "- Two planning modules, namely Goal-Oriented Static Planning (GOSP) module, and Scene-Oriented Dynamic Planning (SODP) module, and one Room-and-Object Aware Scene Perceiver (ROASP) module, are proposed." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 308, + 213, + 530, + 246 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 213, + 530, + 246 + ], + "spans": [ + { + "bbox": [ + 308, + 213, + 530, + 246 + ], + "type": "text", + "content": "- Extensive quantitative and qualitative experiments are conducted on REVERIE to validate the effectiveness of our method." + } + ] + } + ], + "index": 7 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 297, + 256, + 379, + 268 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 256, + 379, + 268 + ], + "spans": [ + { + "bbox": [ + 297, + 256, + 379, + 268 + ], + "type": "text", + "content": "2. Related work" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 276, + 530, + 554 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 276, + 530, + 554 + ], + "spans": [ + { + "bbox": [ + 296, + 276, + 530, + 554 + ], + "type": "text", + "content": "Vision-and-Language Navigation Vision-and-Language Navigation (VLN) has attracted increasing attention in recent years, and many specific VLN tasks have been proposed [7, 19, 24, 27, 29, 36]. Anderson et al. [4] proposes the first VLN benchmark, Room-to-Room (R2R), which requires an agent to navigate from one room to another in a house, according to a detailed natural language step-by-step instruction in a photo-realistic environment. Later, Room-across-Room (RxR) [21] was proposed with longer and more detailed multilingual instructions. Both these two tasks give fine-grained instructions, which makes it easier to navigate to the target location. NDH [36] extends the navigation instruction to the dialogue form, and TouchDown [7] extends the environments to outdoor. REVERIE [27] and SOON [39] are proposed for remote object localization, which requires an agent not only to navigate to the target location, but also to specify the object to interact with. The difference between REVERIE and SOON is that REVERIE uses short concise instructions (e.g., \"bring me the red cup from the kitchen.\") while SOON employs long detailed instructions (e.g., \"I want to find a cylindrical, metallic and tall lamp, which is set in the bright living room. The lamp is on the cabinet which is on the left of the television and next to the window. The living room is on ...\")." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 555, + 530, + 706 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 555, + 530, + 706 + ], + "spans": [ + { + "bbox": [ + 296, + 555, + 530, + 706 + ], + "type": "text", + "content": "Among the aforementioned VLN tasks, the instructions of REVERIE are closer to what we would say to an intelligent domestic robot in daily life in terms of the instruction length and logic, which is usually short and concise. However, most existing methods [2, 11, 14, 16, 26, 28] are usually designed for the VLN tasks where detailed step-by-step instructions are used, thus they do not perform well on REVERIE. In this work, we specifically develop a method for REVERIE. Inspired by the fact of LLMs that implicitly internalize rich knowledge in action planning, we propose to exploit LLM as a fine-grained planner to generate detailed navigation plans from the concise instructions of REVERIE to improve navigation success." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 297, + 706, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 706, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 297, + 706, + 530, + 730 + ], + "type": "text", + "content": "LLMs as Embodied Planner Benefiting from the rise of LLMs, recent works [17, 34] have explored the use of LLMs" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 746, + 301, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 746, + 301, + 756 + ], + "spans": [ + { + "bbox": [ + 277, + 746, + 301, + 756 + ], + "type": "text", + "content": "15759" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 311, + 117, + 320, + 125 + ], + "blocks": [ + { + "bbox": [ + 311, + 117, + 320, + 125 + ], + "lines": [ + { + "bbox": [ + 311, + 117, + 320, + 125 + ], + "spans": [ + { + "bbox": [ + 311, + 117, + 320, + 125 + ], + "type": "image", + "image_path": "2d287ec19b9b3dacf1b36e1f271e5271bca29e9fc29f2915cae0c7ef9fcdc46a.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 349, + 117, + 367, + 125 + ], + "blocks": [ + { + "bbox": [ + 349, + 117, + 367, + 125 + ], + "lines": [ + { + "bbox": [ + 349, + 117, + 367, + 125 + ], + "spans": [ + { + "bbox": [ + 349, + 117, + 367, + 125 + ], + "type": "image", + "image_path": "2da1df1ad04dc53bc1e070729fc1fa91427a6ca4d5af948960bc2bbf0b0e3568.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 468, + 117, + 477, + 125 + ], + "blocks": [ + { + "bbox": [ + 468, + 117, + 477, + 125 + ], + "lines": [ + { + "bbox": [ + 468, + 117, + 477, + 125 + ], + "spans": [ + { + "bbox": [ + 468, + 117, + 477, + 125 + ], + "type": "image", + "image_path": "1b049502b19f12fe0ae918c8b89a5c491aa4c61228cb763ae4f1c5175ffce99e.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 54, + 127, + 520, + 268 + ], + "blocks": [ + { + "bbox": [ + 54, + 113, + 277, + 124 + ], + "lines": [ + { + "bbox": [ + 54, + 113, + 277, + 124 + ], + "spans": [ + { + "bbox": [ + 54, + 113, + 277, + 124 + ], + "type": "text", + "content": "REVERIE instruction: Empty the washing machine on level one." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 54, + 127, + 520, + 268 + ], + "lines": [ + { + "bbox": [ + 54, + 127, + 520, + 268 + ], + "spans": [ + { + "bbox": [ + 54, + 127, + 520, + 268 + ], + "type": "image", + "image_path": "ddb2fd4827834db8178e14901a821a6aa28659560df8d09f7fc9cf04195e11b2.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 277, + 531, + 348 + ], + "lines": [ + { + "bbox": [ + 45, + 277, + 531, + 348 + ], + "spans": [ + { + "bbox": [ + 45, + 277, + 531, + 348 + ], + "type": "text", + "content": "Figure 2: Overview of our March-in-Chat model. The program runs along the vertical arrows from left to right, progressing with the time flow. Our model first performs Goal-Oriented Static Planning (GOSP, Sec. 4.1.1) to reason the target object and its possible lying room; then the Room-and-Object Aware Scene Perceiver (ROASP, Sec. 4.2) perceives what room type the agent currently stands in and what prominent objects can be seen; these information are used by the Scene-Oriented Dynamic Planning module (SODP, Sec. 4.1.2) to generate a detailed instruction to execute. GOSP just runs once, and we repeat ROASP and SODP until the agent chooses to stop or reaches the maximum steps." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 358, + 279, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 358, + 279, + 521 + ], + "spans": [ + { + "bbox": [ + 45, + 358, + 279, + 521 + ], + "type": "text", + "content": "in task planning for various embodied tasks. Huang et al. [17] propose to utilize the frozen LLMs (e.g., GPT-2 [31], GPT-3 [5] and Codex [8]) to plan actions for the embodied agent with in-context learning [5]. SayCan [1] translates a high-level instruction into a list of candidate low-level actions with a probability, which is then multiplied by a value function for action prediction. These two LLM planners are static, which only generate action plans at the beginning of a task. By contrast, Huang et al. [18] propose to introduce the feedback of action progress, detected objects and human assistance into the LLM planner to re-plan atomic actions. One concurrent work by Song et al. [35] injects the detected objects to re-generate high-level plans with a fixed program pattern for the ALFRED [33] task." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 45, + 522, + 279, + 639 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 522, + 279, + 639 + ], + "spans": [ + { + "bbox": [ + 45, + 522, + 279, + 639 + ], + "type": "text", + "content": "However, these above-mentioned methods mainly concentrate on planning atomic actions for object manipulation in a very limited space with simple scenes. By contrast, REVERIE has plenty of much larger and more complicated environments: 90 multi-layer buildings of various styles (e.g., office, home, gym, to name a few). To handle the complex scenarios of REVERIE, we propose a Room-and-Object Aware Scene Perceiver module that helps the LLM planner dynamically interact with the environment in the form of a natural language dialogue." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 650, + 135, + 664 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 650, + 135, + 664 + ], + "spans": [ + { + "bbox": [ + 46, + 650, + 135, + 664 + ], + "type": "text", + "content": "3. Problem Setup" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "text", + "content": "In the REVERIE task, given a concise and high-level instruction referring to a remote object, the agent is expected to navigate to the goal location and identify the target object in previously unseen environments. The environment is defined as an undirected graph " + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "inline_equation", + "content": "\\mathcal{G} = \\{\\mathcal{V},\\mathcal{E}\\}" + }, + { + "bbox": [ + 45, + 671, + 279, + 730 + ], + "type": "text", + "content": ", where" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "spans": [ + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "\\mathcal{V} = \\{V_i\\}_{i=1}^K" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": " denotes " + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": " navigable nodes, and " + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "\\mathcal{E}" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": " denotes connectivity edges. The agent is first placed in a starting node with the initial state " + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "s_0" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": " and perceives a panorama " + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "\\mathcal{R}_t" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": " as the visual observation at each time step " + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": ". The panorama " + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "\\mathcal{R}_t" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": " is split into " + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": " single view images as " + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "\\mathcal{R}_t = \\{r_i\\}_{i=1}^n" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": ". Each single view image " + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "r_i" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": " is represented by an image feature vector and an orientation feature vector. In addition, the object features " + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "\\mathcal{O}_t = \\{o_i\\}_{i=1}^m" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": " of " + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": " objects are extracted from the panorama view using the annotated object bounding boxes or object detectors. Then, the agent makes a sequence of actions " + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "inline_equation", + "content": "\\langle a_0, \\ldots, a_T \\rangle" + }, + { + "bbox": [ + 296, + 357, + 530, + 533 + ], + "type": "text", + "content": " to reach the target location, where each action is achieved by choosing a navigable node from the candidate list. The agent navigates in the environment until the target object is grounded or the agent reaches the predefined maximum trajectory length." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 297, + 545, + 351, + 556 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 545, + 351, + 556 + ], + "spans": [ + { + "bbox": [ + 297, + 545, + 351, + 556 + ], + "type": "text", + "content": "4. Method" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 296, + 566, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 566, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 566, + 530, + 730 + ], + "type": "text", + "content": "As illustrated in Fig. 2, when initially situated at the starting position and given a concise high-level instruction such as \"Empty the washing machine on level one\", the agent first queries an LLM with the GOSP module (Sec. 4.1.1) to find out the target object \"washing machine\" in the instruction and reason out the potential location \"laundry room\" by using the world knowledge implied in an LLM. Then the ROASP module (Sec. 4.2) extracts the room type and visible objects from the current visual observation to obtain the environmental feedback. With the description of the scene perception, the LLM is queried again by the SODP (Sec. 4.1.2) to generate the next step instruction, which is used to guide the agent to navigate to the target object in the room. The baseline agent is based on" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 746, + 301, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 746, + 301, + 756 + ], + "spans": [ + { + "bbox": [ + 277, + 746, + 301, + 756 + ], + "type": "text", + "content": "15760" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 133, + 113, + 227, + 123 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 133, + 113, + 227, + 123 + ], + "spans": [ + { + "bbox": [ + 133, + 113, + 227, + 123 + ], + "type": "text", + "content": "Target Object Recognition" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 90, + 124, + 113, + 132 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 90, + 124, + 113, + 132 + ], + "spans": [ + { + "bbox": [ + 90, + 124, + 113, + 132 + ], + "type": "text", + "content": "Task:" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 90, + 133, + 254, + 142 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 90, + 133, + 254, + 142 + ], + "spans": [ + { + "bbox": [ + 90, + 133, + 254, + 142 + ], + "type": "text", + "content": "Empty the washing machine on level one." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 89, + 147, + 113, + 154 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 89, + 147, + 113, + 154 + ], + "spans": [ + { + "bbox": [ + 89, + 147, + 113, + 154 + ], + "type": "text", + "content": "Goal:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 90, + 156, + 247, + 165 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 90, + 156, + 247, + 165 + ], + "spans": [ + { + "bbox": [ + 90, + 156, + 247, + 165 + ], + "type": "text", + "content": "The target object is: washing machine" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 133, + 178, + 229, + 187 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 133, + 178, + 229, + 187 + ], + "spans": [ + { + "bbox": [ + 133, + 178, + 229, + 187 + ], + "type": "text", + "content": "Target Object Localization" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 87, + 187, + 122, + 197 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 87, + 187, + 122, + 197 + ], + "spans": [ + { + "bbox": [ + 87, + 187, + 122, + 197 + ], + "type": "text", + "content": "Example:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 87, + 197, + 274, + 214 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 87, + 197, + 274, + 214 + ], + "spans": [ + { + "bbox": [ + 87, + 197, + 274, + 214 + ], + "type": "text", + "content": "Question: Where does a microwave can usually appear in a house?" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 87, + 215, + 155, + 223 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 87, + 215, + 155, + 223 + ], + "spans": [ + { + "bbox": [ + 87, + 215, + 155, + 223 + ], + "type": "text", + "content": "Answer: kitchen." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 87, + 229, + 266, + 247 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 87, + 229, + 266, + 247 + ], + "spans": [ + { + "bbox": [ + 87, + 229, + 266, + 247 + ], + "type": "text", + "content": "Question: Where does a washing machine can usually appear in a house?" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 87, + 248, + 174, + 256 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 87, + 248, + 174, + 256 + ], + "spans": [ + { + "bbox": [ + 87, + 248, + 174, + 256 + ], + "type": "text", + "content": "Answer: laundry room" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 98, + 262, + 264, + 271 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 98, + 262, + 264, + 271 + ], + "spans": [ + { + "bbox": [ + 98, + 262, + 264, + 271 + ], + "type": "text", + "content": "(a) Prompt template of Goal-Oriented Static Planning" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 333, + 112, + 440, + 122 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 333, + 112, + 440, + 122 + ], + "spans": [ + { + "bbox": [ + 333, + 112, + 440, + 122 + ], + "type": "text", + "content": "Scene-Oriented Dynamic Plan" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 291, + 132, + 482, + 151 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 291, + 132, + 482, + 151 + ], + "spans": [ + { + "bbox": [ + 291, + 132, + 482, + 151 + ], + "type": "text", + "content": "At this step, I am in bedroom, I can see bed, lamp, pillow." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 292, + 159, + 326, + 168 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 292, + 159, + 326, + 168 + ], + "spans": [ + { + "bbox": [ + 292, + 159, + 326, + 168 + ], + "type": "text", + "content": "Example:" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 292, + 169, + 445, + 178 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 292, + 169, + 445, + 178 + ], + "spans": [ + { + "bbox": [ + 292, + 169, + 445, + 178 + ], + "type": "text", + "content": "Step 1: go straight and out the room" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 292, + 178, + 411, + 186 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 292, + 178, + 411, + 186 + ], + "spans": [ + { + "bbox": [ + 292, + 178, + 411, + 186 + ], + "type": "text", + "content": "Step 2: pass the white table" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 292, + 187, + 482, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 292, + 187, + 482, + 205 + ], + "spans": [ + { + "bbox": [ + 292, + 187, + 482, + 205 + ], + "type": "text", + "content": "Step 3: move into the laundry room across the hall" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 292, + 205, + 394, + 214 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 292, + 205, + 394, + 214 + ], + "spans": [ + { + "bbox": [ + 292, + 205, + 394, + 214 + ], + "type": "text", + "content": "Step 4: stop at the sink" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 291, + 223, + 481, + 242 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 291, + 223, + 481, + 242 + ], + "spans": [ + { + "bbox": [ + 291, + 223, + 481, + 242 + ], + "type": "text", + "content": "Task: Empty the washing machine on level one. Step 1: exit the bedroom" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 294, + 262, + 474, + 271 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 262, + 474, + 271 + ], + "spans": [ + { + "bbox": [ + 294, + 262, + 474, + 271 + ], + "type": "text", + "content": "(b) Prompt template of Scene-Oriented Dynamic Planning" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 45, + 275, + 530, + 299 + ], + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 275, + 530, + 299 + ], + "spans": [ + { + "bbox": [ + 45, + 275, + 530, + 299 + ], + "type": "text", + "content": "Figure 3: Examples of prompting templates for Goal-Oriented Static Planning (a) and Scene-Oriented Dynamic Planning (b). Outputs are marked with green color. And the red denotes the predicted object from Target Object Recognition." + } + ] + } + ], + "index": 21, + "type": "text" + }, + { + "bbox": [ + 45, + 311, + 279, + 335 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 311, + 279, + 335 + ], + "spans": [ + { + "bbox": [ + 45, + 311, + 279, + 335 + ], + "type": "text", + "content": "HM3D-DUET [10], more details can be found in the supplementary material." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 45, + 336, + 272, + 348 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 336, + 272, + 348 + ], + "spans": [ + { + "bbox": [ + 45, + 336, + 272, + 348 + ], + "type": "text", + "content": "4.1. Planning with World Knowledge from LLMs" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 45, + 354, + 279, + 424 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 354, + 279, + 424 + ], + "spans": [ + { + "bbox": [ + 45, + 354, + 279, + 424 + ], + "type": "text", + "content": "This section illustrates how we utilize in-context learning (ICL) [5] to acquire world knowledge from the LLMs for planning. We first briefly introduce in-context learning. Then, we elaborate the Goal-Oriented Static Planning (GOSP) and Scene-Oriented Dynamic Planning (SODP). Last, we show the demonstration selection process." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 45, + 425, + 279, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 425, + 279, + 552 + ], + "spans": [ + { + "bbox": [ + 45, + 425, + 279, + 552 + ], + "type": "text", + "content": "Preliminary: In-context Learning for Planning. In-context learning (ICL) is a paradigm that lets LLMs directly make predictions based on a natural language context without gradient updates [5]. Specifically, under the setting of in-context learning, an LLM is fed a \"prompt\" that usually contains a task description and several demonstrations, and then the LLM generates the required outputs. Both the prompt template and the choice of demonstration examples have an impact on how well ICL performs. In this work, we use two different ICL settings to generate different navigation plans, i.e. the GOSP and SODP module." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 45, + 554, + 279, + 670 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 554, + 279, + 670 + ], + "spans": [ + { + "bbox": [ + 45, + 554, + 279, + 670 + ], + "type": "text", + "content": "The GOSP aims to identify the target object and infer the target location by arousing the world knowledge contained in an LLM through appropriate prompts. A fixed demonstration example is used for GOSP. While the SODP aims to generate step-by-step planning instructions after observing the dynamic scenes from the environment, which is more complicated than the former. To better generate plannings, we dynamically select the most suitable demonstration examples for SODP and incorporate the environmental feedback as prompts for interactive planning." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 45, + 679, + 239, + 691 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 679, + 239, + 691 + ], + "spans": [ + { + "bbox": [ + 45, + 679, + 239, + 691 + ], + "type": "text", + "content": "4.1.1 Goal-Oriented Static Planning (GOSP)" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 45, + 694, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 694, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 694, + 279, + 730 + ], + "type": "text", + "content": "Given a high-level concise instruction, such as \"Empty the washing machine on level one\", an LLM is first asked to generate a goal-oriented static planning instruction: \"Goal:" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 296, + 311, + 530, + 591 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 311, + 530, + 591 + ], + "spans": [ + { + "bbox": [ + 296, + 311, + 530, + 591 + ], + "type": "text", + "content": "The target object is a washing machine. It is usually in a laundry room\", which emphasizes the target object and points out where the target object may lie. As shown in Fig. 3(a), the planning generation mainly consists of two sub-tasks: target object recognition and target object localization, which can be achieved by providing specifically designed prompts for the LLM. To this end, we design the prompts for the former sub-task in the form: \"Task: Empty the washing machine on level one. Goal: The target object is:\". Then the LLM will generate a corresponding answer: \"washing machine\". By contrast, the latter subtask, reasoning out the target location, is more complex because it requires more suitable prompts to arouse the internalized world knowledge in the LLM. To address this problem, we utilize a fixed demonstration example for the LLM, and design the prompts for the latter sub-task in the form: \"Example: Question: Where does a microwave can usually appear in a house? Answer: kitchen. Question: Where does a washing machine can usually appear in a house? Answer: \". Given such prompts, the LLM will generate the corresponding answer \"laundry room\". With these answers, we can easily combine them into the goal-oriented planning format: \"Goal: The target object is a washing machine. It is usually in a laundry room\"." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 296, + 598, + 508, + 610 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 598, + 508, + 610 + ], + "spans": [ + { + "bbox": [ + 296, + 598, + 508, + 610 + ], + "type": "text", + "content": "4.1.2 Scene-Oriented Dynamic Planning (SODP)" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 296, + 613, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 613, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 613, + 530, + 730 + ], + "type": "text", + "content": "As is shown in Fig 3(b), the prompt for SODP consists of three parts. The first part is based on the scene perception of room type, such as \"bedroom\", and visible objects, such as \"bed, lamp, pillow\", obtained by the Room-and-Object Aware Scene Perceiver (ROASP, Sec. 4.2). These information are transformed into a natural language description of the current scene in the format of \"At this step, I am in bedroom, I can see bed, lamp, pillow\". The second part is a demonstration of the fine-grained step-by-step instruction, which is selected according to the strategy" + } + ] + } + ], + "index": 31 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 747, + 299, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 747, + 299, + 756 + ], + "spans": [ + { + "bbox": [ + 277, + 747, + 299, + 756 + ], + "type": "text", + "content": "15761" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 54, + 109, + 70, + 117 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 109, + 70, + 117 + ], + "spans": [ + { + "bbox": [ + 54, + 109, + 70, + 117 + ], + "type": "text", + "content": "R2R" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 54, + 117, + 263, + 134 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 117, + 263, + 134 + ], + "spans": [ + { + "bbox": [ + 54, + 117, + 263, + 134 + ], + "type": "text", + "content": "Go up the stairs and then walk the length of the couch. Walk past the dining area and into the kitchen. Stop in front of the refrigerator." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 54, + 137, + 80, + 143 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 137, + 80, + 143 + ], + "spans": [ + { + "bbox": [ + 54, + 137, + 80, + 143 + ], + "type": "text", + "content": "FGR2R" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 54, + 145, + 200, + 178 + ], + "type": "list", + "angle": 0, + "index": 7, + "blocks": [ + { + "bbox": [ + 54, + 145, + 117, + 154 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 145, + 117, + 154 + ], + "spans": [ + { + "bbox": [ + 54, + 145, + 117, + 154 + ], + "type": "text", + "content": "Step 1: go up the stair" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 54, + 154, + 179, + 161 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 154, + 179, + 161 + ], + "spans": [ + { + "bbox": [ + 54, + 154, + 179, + 161 + ], + "type": "text", + "content": "Step 2: and then walk the length of the couch" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 54, + 162, + 200, + 170 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 162, + 200, + 170 + ], + "spans": [ + { + "bbox": [ + 54, + 162, + 200, + 170 + ], + "type": "text", + "content": "Step 3: walk past the dining area and into the kitchen" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 54, + 170, + 160, + 178 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 170, + 160, + 178 + ], + "spans": [ + { + "bbox": [ + 54, + 170, + 160, + 178 + ], + "type": "text", + "content": "Step 4: stop in front of the refrigerator" + } + ] + } + ], + "index": 6 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 54, + 186, + 269, + 197 + ], + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 186, + 269, + 197 + ], + "spans": [ + { + "bbox": [ + 54, + 186, + 269, + 197 + ], + "type": "text", + "content": "Figure 4: Example of instructions in R2R and FGR2R." + } + ] + } + ], + "index": 8, + "type": "text" + }, + { + "bbox": [ + 45, + 208, + 279, + 278 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 208, + 279, + 278 + ], + "spans": [ + { + "bbox": [ + 45, + 208, + 279, + 278 + ], + "type": "text", + "content": "detailed in the next section. The last part is previous instructions, such as \"Task: Empty the washing machine on level one. Step 1:\". All these three parts are concatenated together and then fed into an LLM to generate the fine-grained planning instruction for the next step accordingly, such as \"Exit the bedroom\"." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 45, + 286, + 219, + 297 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 286, + 219, + 297 + ], + "spans": [ + { + "bbox": [ + 45, + 286, + 219, + 297 + ], + "type": "text", + "content": "4.1.3 Dynamic Demonstration Selection" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 45, + 300, + 279, + 393 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 300, + 279, + 393 + ], + "spans": [ + { + "bbox": [ + 45, + 300, + 279, + 393 + ], + "type": "text", + "content": "Recent works show that providing various demonstration examples to LLMs benefits the in-context learning for different tasks [17, 22, 25]. In light of these findings, to direct the LLMs in generating better fine-grained plannings, we dynamically select the most suitable demonstration example for each specific task in REVERIE as the prompt to generate the environment-aware instruction, contrary to using a single fixed demonstration for all tasks." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "spans": [ + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "content": "Specifically, we choose the training set of the Fine-Grained R2R dataset (FGR2R) [15] as the demonstration set " + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "content": ", of which each sample will be used as a demonstration example " + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "inline_equation", + "content": "D_{step}" + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "content": ". As shown in Fig. 4, FGR2R decomposes each low-level instruction " + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "inline_equation", + "content": "I_{low}" + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "content": " of R2R dataset [4] into step-by-step instructions " + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "inline_equation", + "content": "I_{step}" + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "content": ". Then, given a high-level instruction " + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "inline_equation", + "content": "I_{high}" + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "content": " of REVERIE, a proper " + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "inline_equation", + "content": "I_{low}" + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "content": " will be selected as the demonstration example " + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "inline_equation", + "content": "D_{step}" + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "content": " by a matching algorithm. In particular, we use " + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "inline_equation", + "content": "I_{high}" + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "content": " as query " + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "content": " and each low-level instruction " + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "inline_equation", + "content": "I_{low}" + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "content": " as the key " + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "inline_equation", + "content": "K_i" + }, + { + "bbox": [ + 45, + 394, + 279, + 545 + ], + "type": "text", + "content": ", both of which are embedded by the Sentence-BERT [32]. The semantic distance score between the two embeddings is calculated by the cosine similarity:" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 104, + 554, + 279, + 580 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 104, + 554, + 279, + 580 + ], + "spans": [ + { + "bbox": [ + 104, + 554, + 279, + 580 + ], + "type": "interline_equation", + "content": "\\mathrm {s} (Q, K _ {i}) = \\frac {e (Q) \\cdot e (K _ {i})}{\\| e (Q) \\| \\| e (K _ {i}) \\|}, \\tag {1}", + "image_path": "cc7b11eac7dd9c098a988bc8d1c6e280cb5f867cb0f49200d69284f82099eba3.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "spans": [ + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "inline_equation", + "content": "e(\\cdot)" + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "text", + "content": " is the embedding function. If " + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "inline_equation", + "content": "K_{i}" + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "text", + "content": " has the highest similarity score to the given query " + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "text", + "content": ", its corresponding step-by-step instruction " + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "inline_equation", + "content": "I_{step}" + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "text", + "content": " will be selected as the demonstration example " + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "inline_equation", + "content": "D_{step}" + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "text", + "content": " for the given high-level instruction " + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "inline_equation", + "content": "I_{high}" + }, + { + "bbox": [ + 45, + 587, + 279, + 646 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 45, + 653, + 255, + 665 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 653, + 255, + 665 + ], + "spans": [ + { + "bbox": [ + 45, + 653, + 255, + 665 + ], + "type": "text", + "content": "4.2. Room-and-Object Aware Scene Perceiver" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 45, + 671, + 279, + 729 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 671, + 279, + 729 + ], + "spans": [ + { + "bbox": [ + 45, + 671, + 279, + 729 + ], + "type": "text", + "content": "Though the world knowledge acquired from the static LLMs planner could benefit the embodied task promisingly, the static LLMs planner may generate wrong or irrelevant plannings, which misleads the agent. To address this issue, the LLM planner should be aware of and interact with the" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 296, + 106, + 530, + 303 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 106, + 530, + 303 + ], + "spans": [ + { + "bbox": [ + 296, + 106, + 530, + 303 + ], + "type": "text", + "content": "dynamic observations. In [35], the names of objects obtained from the ground truth or pre-trained detectors have been added to in-context prompts. However, the agents of these works act in a very limited space with simple scenes and monotonous objects. By contrast, REVERIE involves large-area exploration between different floors and rooms, where the scenes are more complex with more diverse objects. Considering these factors, we propose a room-and-object aware scene perceiver (ROASP) for the LLM planner, which predicts not only the room type but also the visible objects of the current location. Rather than using separate classifiers and detectors to individually predict each position's room types and visible object categories, we use CLIP [30] as the proposed room-and-object aware scene perceiver. Thanks to CLIP's strong ability of zero-shot image classification in the open world, the ROASP can well handle these two tasks." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "spans": [ + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "text", + "content": "Specifically, we first fetch the room type labels from the MatterPort3D [6] semantic annotations and the object type labels are extracted from the REVERIE training dataset. They are used to build the codebook for the room categories " + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "inline_equation", + "content": "\\mathbf{C}_{\\mathrm{room}}" + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "text", + "content": " and the object categories " + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "inline_equation", + "content": "\\mathbf{C}_{\\mathrm{obj}}" + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "text", + "content": ", respectively. Then, at each timestep " + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "text", + "content": ", the agent perceives the environment and obtains the panoramic visual observation " + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "inline_equation", + "content": "\\mathcal{R}_t = \\{r_i\\}_{i=1}^n" + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "text", + "content": ". For each single-view observation " + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "inline_equation", + "content": "r_i" + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "text", + "content": " in the panorama, the image feature " + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{r}}" + }, + { + "bbox": [ + 296, + 303, + 530, + 408 + ], + "type": "text", + "content": " is extracted by the CLIP Image Encoder" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 381, + 417, + 530, + 431 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 381, + 417, + 530, + 431 + ], + "spans": [ + { + "bbox": [ + 381, + 417, + 530, + 431 + ], + "type": "interline_equation", + "content": "f _ {\\mathrm {r}} = E _ {\\mathrm {C L I P}} ^ {v} \\left(r _ {i}\\right), \\tag {2}", + "image_path": "ba0bbe56e8b9e6e5ead645b9a1d42555a0ef4a68074c1e7ed16234e38ef19695.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "spans": [ + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "inline_equation", + "content": "E_{\\mathrm{CLIP}}^v (\\cdot)" + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "text", + "content": " represents the CLIP Image Encoder. For each room category " + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "inline_equation", + "content": "c_{room}" + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "text", + "content": " and each object category " + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "inline_equation", + "content": "c_{obj}" + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "text", + "content": ", we respectively construct a text phrase of room " + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "inline_equation", + "content": "T_{\\mathrm{room}}" + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "text", + "content": " as \"a photo of a " + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "inline_equation", + "content": "\\{c_{room}\\}" + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "text", + "content": "\" and a text phrase of object " + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "inline_equation", + "content": "T_{\\mathrm{obj}}" + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "text", + "content": " as \"a photo of a " + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "inline_equation", + "content": "\\{c_{obj}\\}" + }, + { + "bbox": [ + 296, + 439, + 530, + 508 + ], + "type": "text", + "content": "\". Then the text feature is derived through the pretrained CLIP Text Encoder as:" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 369, + 517, + 530, + 531 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 369, + 517, + 530, + 531 + ], + "spans": [ + { + "bbox": [ + 369, + 517, + 530, + 531 + ], + "type": "interline_equation", + "content": "f _ {\\text {r o o m}} = E _ {\\text {C L I P}} ^ {t} \\left(T _ {\\text {r o o m}}\\right), \\tag {3}", + "image_path": "0a8fe8a3fe0ed28c72a7e3e66fa658cfa8f0a27107343cb099bf54d114a02e29.jpg" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 375, + 533, + 530, + 547 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 375, + 533, + 530, + 547 + ], + "spans": [ + { + "bbox": [ + 375, + 533, + 530, + 547 + ], + "type": "interline_equation", + "content": "f _ {\\mathrm {o b j}} = E _ {\\mathrm {C L I P}} ^ {t} \\left(T _ {\\mathrm {o b j}}\\right), \\tag {4}", + "image_path": "4fcee2fbf2832236f8970a4ee23e720d5d740be004bd76f8bd677844d373ae02.jpg" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "spans": [ + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "inline_equation", + "content": "E_{\\mathrm{CLIP}}^{t}(\\cdot)" + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "text", + "content": " represents the CLIP Text Encoder. At last, the similarity score " + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "inline_equation", + "content": "S_{\\mathrm{room}}" + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "text", + "content": " between the image feature " + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{r}}" + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "text", + "content": " and the text feature " + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{room}}" + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "text", + "content": " as well as the similarity score " + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "inline_equation", + "content": "S_{\\mathrm{obj}}" + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "text", + "content": " between the image feature " + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{r}}" + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "text", + "content": " and the text feature " + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "inline_equation", + "content": "f_{\\mathrm{obj}}" + }, + { + "bbox": [ + 296, + 554, + 530, + 613 + ], + "type": "text", + "content": " are respectively computed as:" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 354, + 621, + 530, + 635 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 354, + 621, + 530, + 635 + ], + "spans": [ + { + "bbox": [ + 354, + 621, + 530, + 635 + ], + "type": "interline_equation", + "content": "S _ {\\text {r o o m}} = \\operatorname {S o f t m a x} \\left(f _ {\\text {r o o m}} \\cdot f _ {\\mathrm {r}} ^ {T}\\right), \\tag {5}", + "image_path": "f1a20e2d3865d87ead58a3e4aaaaa3125b0ef369c8fa6911abcf64c91485f320.jpg" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 361, + 637, + 530, + 651 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 361, + 637, + 530, + 651 + ], + "spans": [ + { + "bbox": [ + 361, + 637, + 530, + 651 + ], + "type": "interline_equation", + "content": "S _ {\\mathrm {o b j}} = \\operatorname {S o f t m a x} \\left(f _ {\\mathrm {o b j}} \\cdot f _ {\\mathrm {r}} ^ {T}\\right). \\tag {6}", + "image_path": "759fbb1b4a293fc0ead607c02f636969d37aaf79dcd68ad6f52cbf943bbb4619.jpg" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 296, + 660, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 660, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 660, + 530, + 730 + ], + "type": "text", + "content": "Considering that the current environment normally belongs to only one type of room, though the panoramic images have multiple views, the room that the agent is currently centered in should have the largest influence on each view. Thus, we average the predicted room type scores " + }, + { + "bbox": [ + 296, + 660, + 530, + 730 + ], + "type": "inline_equation", + "content": "S_{\\mathrm{room}}" + }, + { + "bbox": [ + 296, + 660, + 530, + 730 + ], + "type": "text", + "content": " from multiple views and choose the room type with" + } + ] + } + ], + "index": 26 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "spans": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "type": "text", + "content": "15762" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 52, + 110, + 272, + 184 + ], + "blocks": [ + { + "bbox": [ + 52, + 110, + 272, + 184 + ], + "lines": [ + { + "bbox": [ + 52, + 110, + 272, + 184 + ], + "spans": [ + { + "bbox": [ + 52, + 110, + 272, + 184 + ], + "type": "table", + "html": "
HLIEmpty the washing machine on level one.
GOSPGoal: The target object is washing machine. It is usually in laundry room.
SODPStep 1: exit the bedroom\nStep 2: go down the stairs\n...
", + "image_path": "18e1bf467aecaa44b6494c6dd77a62d55c863bf9a317af95f33cc9741a084ffe.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 45, + 190, + 279, + 237 + ], + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 190, + 279, + 237 + ], + "spans": [ + { + "bbox": [ + 45, + 190, + 279, + 237 + ], + "type": "text", + "content": "Figure 5: Text inputs contains three parts: High-level Instruction in REVERIE (HLI), Goal-Oriented Static Planning (GOSP) and Scene-Oriented Dynamic Planning (SODP) returned instructions." + } + ] + } + ], + "index": 1, + "type": "text" + }, + { + "bbox": [ + 45, + 249, + 279, + 318 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 249, + 279, + 318 + ], + "spans": [ + { + "bbox": [ + 45, + 249, + 279, + 318 + ], + "type": "text", + "content": "the greatest score as the room type prediction " + }, + { + "bbox": [ + 45, + 249, + 279, + 318 + ], + "type": "inline_equation", + "content": "\\hat{c}_{\\mathrm{room}}" + }, + { + "bbox": [ + 45, + 249, + 279, + 318 + ], + "type": "text", + "content": ". For object predictions, if the object occupies more proportion in a view, the matching score " + }, + { + "bbox": [ + 45, + 249, + 279, + 318 + ], + "type": "inline_equation", + "content": "S_{\\mathrm{obj}}" + }, + { + "bbox": [ + 45, + 249, + 279, + 318 + ], + "type": "text", + "content": " should be higher. Thus, we select " + }, + { + "bbox": [ + 45, + 249, + 279, + 318 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 45, + 249, + 279, + 318 + ], + "type": "text", + "content": " prominent objects with the top-" + }, + { + "bbox": [ + 45, + 249, + 279, + 318 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 45, + 249, + 279, + 318 + ], + "type": "text", + "content": " matching scores as the auxiliary environment feedback in addition to the predicted room." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 326, + 226, + 340 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 326, + 226, + 340 + ], + "spans": [ + { + "bbox": [ + 45, + 326, + 226, + 340 + ], + "type": "text", + "content": "4.3. March with Interactive Prompting" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 45, + 345, + 279, + 437 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 345, + 279, + 437 + ], + "spans": [ + { + "bbox": [ + 45, + 345, + 279, + 437 + ], + "type": "text", + "content": "When the generation of the goal-oriented planning and the scene-oriented planning with perceptions from the environment is finished, the agent can march towards the target object at each timestep " + }, + { + "bbox": [ + 45, + 345, + 279, + 437 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 45, + 345, + 279, + 437 + ], + "type": "text", + "content": " under the guidance of the interactive prompting. In this section, we will give a detailed description of how the interactive prompting works during the process of navigation, which mainly consists of two parts, i.e. the assembled instruction and the instruction update." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "spans": [ + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "text", + "content": "Assembled Instruction At each timestep " + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "text", + "content": ", the agent observes the environment and receives the assembled instructions obtained from the above-mentioned modules, and choose an action to perform. Specifically, as shown in Fig. 5, the assembled instructions " + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "inline_equation", + "content": "W" + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "text", + "content": " of the interactive prompting mainly consist of three parts: the high-level instruction (HLI) " + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "inline_equation", + "content": "W_{I}" + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "text", + "content": " in REVERIE, the GOSP instruction " + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "inline_equation", + "content": "W_{G}" + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "text", + "content": " and the SODP instruction " + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "inline_equation", + "content": "W_{S}" + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "text", + "content": ". We concatenate these three parts of instructions as the assembled instruction " + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "inline_equation", + "content": "W = [W_{I}, W_{G}, W_{S}]" + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "text", + "content": " and use WordPieces [20] to tokenize all the words into a sequence of tokens as the textual input for the agent. Then, the agent will act under the guidance of such assembled instruction. Note that the use of the original high-level instruction " + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "inline_equation", + "content": "W_{I}" + }, + { + "bbox": [ + 45, + 444, + 279, + 618 + ], + "type": "text", + "content": " can improve the model's tolerance on the noise of intermediate planning instructions." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 624, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 624, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 624, + 279, + 730 + ], + "type": "text", + "content": "Instruction Update The GOSP is only conducted once at the beginning of the task. While the SODP is conducted depending on the feedback of environments. Specifically, at each timestep " + }, + { + "bbox": [ + 45, + 624, + 279, + 730 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 45, + 624, + 279, + 730 + ], + "type": "text", + "content": ", if the ROASP finds the room has changed where the predicted room " + }, + { + "bbox": [ + 45, + 624, + 279, + 730 + ], + "type": "inline_equation", + "content": "\\hat{c}_{\\mathrm{room}}^t" + }, + { + "bbox": [ + 45, + 624, + 279, + 730 + ], + "type": "text", + "content": " does not equal to " + }, + { + "bbox": [ + 45, + 624, + 279, + 730 + ], + "type": "inline_equation", + "content": "\\hat{c}_{\\mathrm{room}}^{t-1}" + }, + { + "bbox": [ + 45, + 624, + 279, + 730 + ], + "type": "text", + "content": ", the SODP will be triggered again. Then, a new step-by-step instruction such as \"Step 2: go down the stairs\" for the next few steps will be generated by the LLM and added to the previous assembled instruction " + }, + { + "bbox": [ + 45, + 624, + 279, + 730 + ], + "type": "inline_equation", + "content": "W" + }, + { + "bbox": [ + 45, + 624, + 279, + 730 + ], + "type": "text", + "content": " after the last step-by-step" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 296, + 106, + 530, + 129 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 106, + 530, + 129 + ], + "spans": [ + { + "bbox": [ + 296, + 106, + 530, + 129 + ], + "type": "text", + "content": "instruction of \"Step 1: exit the bedroom\". Then, the agent will act under the guidance of the updated instructions " + }, + { + "bbox": [ + 296, + 106, + 530, + 129 + ], + "type": "inline_equation", + "content": "W'" + }, + { + "bbox": [ + 296, + 106, + 530, + 129 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 297, + 141, + 371, + 154 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 141, + 371, + 154 + ], + "spans": [ + { + "bbox": [ + 297, + 141, + 371, + 154 + ], + "type": "text", + "content": "5. Experiment" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 297, + 161, + 398, + 173 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 161, + 398, + 173 + ], + "spans": [ + { + "bbox": [ + 297, + 161, + 398, + 173 + ], + "type": "text", + "content": "5.1. Evaluation Setup" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 179, + 530, + 260 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 179, + 530, + 260 + ], + "spans": [ + { + "bbox": [ + 296, + 179, + 530, + 260 + ], + "type": "text", + "content": "Dataset REVERIE [27] contains 10,567 panoramic images within 90 buildings (4,140 target objects divided into 489 categories) and 21,702 instructions with 18 words on average. Each target viewpoint has 7 distinct panoramic objects with 50 bounding boxes on average. It consists of four splits: train, validation seen, validation unseen and test unseen." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 270, + 530, + 373 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 270, + 530, + 373 + ], + "spans": [ + { + "bbox": [ + 296, + 270, + 530, + 373 + ], + "type": "text", + "content": "Evaluation Metrics The performance of agents is evaluated in two ways: navigation and object grounding. For the navigation sub-task, the metrics are Success Rate (SR), Oracle Success Rate (OSR), and Success weighted by Path Length [3] (SPL), where SPL is the main metric. For the grounding sub-task, the metrics are Remote Grounding Success rate (RGS) and RGS weighted by Path Length (RGSPL), where RGSPL is the main metric for this subtask. For all these metrics, higher is better." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 297, + 372, + 530, + 557 + ], + "type": "list", + "angle": 0, + "index": 18, + "blocks": [ + { + "bbox": [ + 314, + 372, + 530, + 394 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 314, + 372, + 530, + 394 + ], + "spans": [ + { + "bbox": [ + 314, + 372, + 530, + 394 + ], + "type": "text", + "content": "TL Trajectory Length measures the average length of all the predicted navigation trajectories in meters." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 315, + 395, + 530, + 429 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 395, + 530, + 429 + ], + "spans": [ + { + "bbox": [ + 315, + 395, + 530, + 429 + ], + "type": "text", + "content": "SR Success Rate measures the ratio of successful tasks, of which the agent's stop location is less than 3 meters away from the target location." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 309, + 430, + 530, + 463 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 430, + 530, + 463 + ], + "spans": [ + { + "bbox": [ + 309, + 430, + 530, + 463 + ], + "type": "text", + "content": "OSR Oracle Success Rate measures the ratio of tasks of which one of its trajectory viewpoints can observe the target object within 3 meters." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 309, + 465, + 530, + 510 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 465, + 530, + 510 + ], + "spans": [ + { + "bbox": [ + 309, + 465, + 530, + 510 + ], + "type": "text", + "content": "SPL Success weighted by Path Length trades-off SR (Success Rate) against TL (Trajectory Length). It measures both the accuracy and efficiency of navigation." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 309, + 511, + 530, + 545 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 511, + 530, + 545 + ], + "spans": [ + { + "bbox": [ + 309, + 511, + 530, + 545 + ], + "type": "text", + "content": "RGS Remote Grounding Success rate measures the ratio of tasks that successfully locate the target object." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 297, + 546, + 492, + 557 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 546, + 492, + 557 + ], + "spans": [ + { + "bbox": [ + 297, + 546, + 492, + 557 + ], + "type": "text", + "content": "RGSPL RGS weighted by Path Length is RGS." + } + ] + } + ], + "index": 17 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 296, + 575, + 530, + 679 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 575, + 530, + 679 + ], + "spans": [ + { + "bbox": [ + 296, + 575, + 530, + 679 + ], + "type": "text", + "content": "Implementation Details Our model is trained on a single 3090 GPU for 30,000 iterations. We set the batch size to 4 and the learning rate to " + }, + { + "bbox": [ + 296, + 575, + 530, + 679 + ], + "type": "inline_equation", + "content": "1 \\times 10^{-5}" + }, + { + "bbox": [ + 296, + 575, + 530, + 679 + ], + "type": "text", + "content": ". The best model is selected according to performance on the validation unseen split. We use the same pretrained model and augmented data as [10] for a fair comparison. For the LLMs, we use the public GPT-2 [31] model for in-context learning. For the scene preceptor, we keep the top 3 object predictions for each position." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 297, + 687, + 520, + 700 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 687, + 520, + 700 + ], + "spans": [ + { + "bbox": [ + 297, + 687, + 520, + 700 + ], + "type": "text", + "content": "5.2. Comparison with State-of-The-Art Methods" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 297, + 706, + 530, + 729 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 706, + 530, + 729 + ], + "spans": [ + { + "bbox": [ + 297, + 706, + 530, + 729 + ], + "type": "text", + "content": "As shown in Table 1, we compare MiC with the state-of-the-art methods on the REVERIE benchmark. Our method" + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "spans": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "type": "text", + "content": "15763" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 73, + 104, + 505, + 297 + ], + "blocks": [ + { + "bbox": [ + 73, + 104, + 505, + 297 + ], + "lines": [ + { + "bbox": [ + 73, + 104, + 505, + 297 + ], + "spans": [ + { + "bbox": [ + 73, + 104, + 505, + 297 + ], + "type": "table", + "html": "
MethodsVal UnseenTest Unseen
NavigationGroundingNavigationGrounding
TLOSR↑SR↑SPL↑RGS↑RGSPL↑TLOSR↑SR↑SPL↑RGS↑RGSPL↑
Human------21.1886.8381.5153.6677.8451.44
Seq2Seq11.078.074.202.842.161.6310.896.883.993.092.001.58
RCM [37]11.9814.239.296.974.8910.607.843.8911.686.673.673.14
SMNA [23]9.0711.288.156.444.543.619.238.395.804.533.102.39
FAST-MATTN [27]45.2828.2014.407.197.844.6739.0530.6319.8811.6111.286.08
ORIST [26]10.9025.0216.8415.148.527.5811.3829.2022.1918.9710.689.28
CKR [12]26.2631.4419.1411.8411.45-22.4630.4022.0014.2511.60-
RecBERT [16]16.7835.0230.6724.9018.7715.2715.8632.9129.6123.9916.5013.51
Airbert [13]18.7134.5127.8921.8818.2314.1817.9134.2030.2823.6116.8313.28
HAMT [9]14.0836.8432.9530.2018.9217.2813.6233.4130.4026.6714.8812.08
HOP [28]16.4636.2431.7826.1118.8515.7316.3833.0630.1724.3417.6914.34
TD-STP [38]-39.4834.8827.3221.1616.56-40.2635.8927.5119.8815.40
DUET [11]22.1151.0746.9833.7332.1523.0321.3056.9152.5136.0631.8822.06
HM3D-DUET [10]-62.1455.8940.8536.5826.76-62.3055.1738.8832.2322.68
MiC20.6462.3756.9743.6037.5228.7218.1162.4055.7441.9735.2526.17
", + "image_path": "49851f2a469df671cd5cdc9eaaaabec3a091afe21b35604c93a53dd24584b0f5.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 54, + 328, + 273, + 394 + ], + "blocks": [ + { + "bbox": [ + 151, + 305, + 423, + 317 + ], + "lines": [ + { + "bbox": [ + 151, + 305, + 423, + 317 + ], + "spans": [ + { + "bbox": [ + 151, + 305, + 423, + 317 + ], + "type": "text", + "content": "Table 1: Comparison with the state-of-the-art methods on REVERIE." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 54, + 328, + 273, + 394 + ], + "lines": [ + { + "bbox": [ + 54, + 328, + 273, + 394 + ], + "spans": [ + { + "bbox": [ + 54, + 328, + 273, + 394 + ], + "type": "table", + "html": "
ComponentsNavigationGrounding
OSR↑SR↑SPL↑RGS↑RGSPL↑
HLI(Baseline)58.0252.7140.4934.9326.82
HLI+GOSP59.9255.2842.4637.1328.24
HLI+SODP60.7256.2642.9436.8027.81
HLI+GOSP+SODP62.3756.9743.6037.5228.72
", + "image_path": "d205d02a16aad0d054092167497f3796383761f63ba0407b13a21a15f6f40f15.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 424, + 279, + 541 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 424, + 279, + 541 + ], + "spans": [ + { + "bbox": [ + 45, + 424, + 279, + 541 + ], + "type": "text", + "content": "outperforms previous methods in all metrics on both validation unseen and test unseen splits. Particularly, compared with the SoTA method HM3D-DUET [10], MiC outperforms HM3D-DUET by a large margin of " + }, + { + "bbox": [ + 45, + 424, + 279, + 541 + ], + "type": "inline_equation", + "content": "3.09\\%" + }, + { + "bbox": [ + 45, + 424, + 279, + 541 + ], + "type": "text", + "content": " in terms of the main navigation metric SPL and " + }, + { + "bbox": [ + 45, + 424, + 279, + 541 + ], + "type": "inline_equation", + "content": "3.49\\%" + }, + { + "bbox": [ + 45, + 424, + 279, + 541 + ], + "type": "text", + "content": " of the main object grounding metric RGSPL on the Test Unseen split. Note that MiC shares the same pre-trained model with the HM3D-DUET, these promising result demonstrates that our method can effectively improve the navigation and object grounding ability of agents." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 548, + 149, + 561 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 548, + 149, + 561 + ], + "spans": [ + { + "bbox": [ + 45, + 548, + 149, + 561 + ], + "type": "text", + "content": "5.3. Ablation Analysis" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 566, + 279, + 612 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 566, + 279, + 612 + ], + "spans": [ + { + "bbox": [ + 45, + 566, + 279, + 612 + ], + "type": "text", + "content": "Contribution of different MiC Components In Table 2, we evaluate the effect of different components in our proposed MiC. HLI denotes only using the original high-level instruction (HLI) provided by REVERIE." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "text", + "content": "Compared to the baseline HLI, GOSP improves the performance of both navigation " + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "inline_equation", + "content": "(2.57\\% \\uparrow" + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "text", + "content": " on SR, " + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "inline_equation", + "content": "1.97\\% \\uparrow" + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "text", + "content": " on SPL) and object grounding " + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "inline_equation", + "content": "(2.20\\% \\uparrow" + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "text", + "content": " on RGS, " + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "inline_equation", + "content": "1.42\\% \\uparrow" + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "text", + "content": " on RGSPL) with a non-trivial margin, showing the effectiveness of the proposed goal-oriented static planning. SODP further surpasses GOSP in the navigation metric " + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "inline_equation", + "content": "(0.98\\% \\uparrow" + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "text", + "content": " on SR, " + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "inline_equation", + "content": "0.48\\% \\uparrow" + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "text", + "content": " on SPL) while falling a little behind in the grounding metrics " + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "inline_equation", + "content": "(0.33\\% \\uparrow" + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "text", + "content": " on RGS, " + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "inline_equation", + "content": "1.43\\% \\uparrow" + }, + { + "bbox": [ + 45, + 613, + 279, + 730 + ], + "type": "text", + "content": " on RGSPL). The reason may be that the detailed step-by-step planning occupies a large proportion compared to the target object" + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 311, + 328, + 518, + 390 + ], + "blocks": [ + { + "bbox": [ + 62, + 401, + 261, + 413 + ], + "lines": [ + { + "bbox": [ + 62, + 401, + 261, + 413 + ], + "spans": [ + { + "bbox": [ + 62, + 401, + 261, + 413 + ], + "type": "text", + "content": "Table 2: Ablation of different components in MiC." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 311, + 328, + 518, + 390 + ], + "lines": [ + { + "bbox": [ + 311, + 328, + 518, + 390 + ], + "spans": [ + { + "bbox": [ + 311, + 328, + 518, + 390 + ], + "type": "table", + "html": "
MethodsNavigationGrounding
OSR↑SR↑SPL↑RGS↑RGSPL↑
Baseline58.0252.7140.4934.9326.82
Static60.2455.3541.7436.3027.03
Dynamic60.7256.2642.9436.8027.81
", + "image_path": "a2ba68531f997a076ed6bf34c2096f4ea1fbfa5372642939d8ccd6c8ec880e63.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 301, + 424, + 529, + 474 + ], + "blocks": [ + { + "bbox": [ + 299, + 399, + 527, + 410 + ], + "lines": [ + { + "bbox": [ + 299, + 399, + 527, + 410 + ], + "spans": [ + { + "bbox": [ + 299, + 399, + 527, + 410 + ], + "type": "text", + "content": "Table 3: Comparison of different plan generation settings." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 301, + 424, + 529, + 474 + ], + "lines": [ + { + "bbox": [ + 301, + 424, + 529, + 474 + ], + "spans": [ + { + "bbox": [ + 301, + 424, + 529, + 474 + ], + "type": "table", + "html": "
MethodsRelevancyRationality
Scene-Oriented Dynamic Planning2.061.93
- w/o Dynamic Demonstration1.411.23
- w/o ROASP1.641.55
", + "image_path": "9c4826c6181c9e81b365540a6379fb9ef0796cfc6dde1224f00fcb07a2fd5b50.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 483, + 530, + 506 + ], + "lines": [ + { + "bbox": [ + 296, + 483, + 530, + 506 + ], + "spans": [ + { + "bbox": [ + 296, + 483, + 530, + 506 + ], + "type": "text", + "content": "Table 4: Human study of the prompt setting for Scene-Oriented Dynamic Planning." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 296, + 519, + 530, + 612 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 519, + 530, + 612 + ], + "spans": [ + { + "bbox": [ + 296, + 519, + 530, + 612 + ], + "type": "text", + "content": "in the input texts, which can bring the noise for object grounding while improving navigation performance. When combining all these components, the final performance gets further increased in all metrics, which surpasses the baseline with a large margin (4.26%↑ on SR, 3.11%↑ on SPL, 2.59%↑ on RGS and 1.9%↑ on RGSPL). The promising results here show that these components are complementary to each other." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 624, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 624, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 624, + 530, + 730 + ], + "type": "text", + "content": "The Effect of the ROASP To evaluate the effectiveness of ROASP used for the scene-oriented dynamic planning, we conduct another ablation study via whether incorporating the feedback from the ROASP module on REVERIE validation unseen set. We report results in three settings: (I) Baseline: The input assembled instruction only contains the given high-level instruction in REVERIE. (II) Static: The input assembled instruction contains the REVERIE and fine-grained static instructions. The difference between" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "spans": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "type": "text", + "content": "15764" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 57, + 110, + 521, + 294 + ], + "blocks": [ + { + "bbox": [ + 57, + 110, + 521, + 294 + ], + "lines": [ + { + "bbox": [ + 57, + 110, + 521, + 294 + ], + "spans": [ + { + "bbox": [ + 57, + 110, + 521, + 294 + ], + "type": "table", + "html": "
REVERIE Instruction: Go to the bathroom with the two towels and empty the lower cabinet.
Scene-Oriented Dynamic Planningw/o Dynamic Demonstrationw/o ROASP
Step 1: exit the bedroomStep 1: put the towel in the bottom drawer of the toiletStep 1: exit the bathroom
Step 2: and walk into the next bedroom in the hallStep 2: walk into the kitchen
Step 3: go stand in the kitchen doorway
Step 3: go stand in the bathroomStep 4: go back to the bedroom and take the towel
Step 5: exit the bedroom
Step 6: walk into the next bedroom in the hall
REVERIE Instruction: Go to the kitchen on level 2 and open the drawer.
Scene-Oriented Dynamic Planningw/o Dynamic Demonstrationw/o ROASP
Step 1: go upstairsStep 1: open the drawer with the key in itStep 1: go upstairs and turn left at the hall
Step 2: go straight pass the couchStep 2: remove the lock from the doorStep 2: go back down the stairs
Step 3: make a slight left towards the refrigeratorStep 3: then turn onStep 3: go up the stairs again
Step 4: wait near the kitchen drawerStep 4: go back to the kitchen and open the fridge
Step 5: take out the fruit and put it in the juicer
", + "image_path": "388916c8cba04ced0696f35036aed1758ff7903a6c11a0c3aaa5c5c89f16678c.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 198, + 303, + 377, + 314 + ], + "angle": 0, + "lines": [ + { + "bbox": [ + 198, + 303, + 377, + 314 + ], + "spans": [ + { + "bbox": [ + 198, + 303, + 377, + 314 + ], + "type": "text", + "content": "Figure 6: Examples of generated instructions." + } + ] + } + ], + "index": 1, + "type": "text" + }, + { + "bbox": [ + 45, + 321, + 281, + 484 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 321, + 281, + 484 + ], + "spans": [ + { + "bbox": [ + 45, + 321, + 281, + 484 + ], + "type": "text", + "content": "fine-grained static instruction and scene-oriented dynamic instruction is that static fine-grained instruction is generated without ROASP. More specifically, the query prompt for the LLM to generate step-by-step planning is fixed at each timestep, which only consists of the given high-level instruction and the selected demonstration. (III) Dynamic: The input assembled instruction contains the high-level instruction in REVERIE and scene-oriented dynamic planning instruction. As shown in Table 3, in the static setting, the performance in all metrics is improved compared to the baseline, indicating the effectiveness of the LLM's rich world knowledge in fine-grained planning. In the dynamic setting, the performance is further improved with non-trivial margins, showing the effectiveness of ROASP." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 497, + 279, + 706 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 497, + 279, + 706 + ], + "spans": [ + { + "bbox": [ + 45, + 497, + 279, + 706 + ], + "type": "text", + "content": "Qualitative Analysis of Prompt Setting To further evaluate the effect of dynamic demonstration and ROASP in SODP, we perform a human evaluation about the generated plannings (see Table 4) and show the planning results (see Fig. 6). For human evaluation, we randomly selected 100 REVERIE tasks and generate fine-grained step-by-step instructions in setting of SODP, SODP without dynamic demonstration, and SODP without ROASP. We asked 10 volunteers to mark the generated step-by-step instructions in terms of their relevancy and rationality. The relevancy score ranges from 0 (unrelated) to 3 (very related), which takes into account whether the keywords in instructions are related to the REVERIE task. For example, regarding the REVERIE instruction \"Go to the kitchen and turn on the microwave\", whether there are keywords in instructions related to the kitchen scene could be rated. Rationality is rated from 0 (bad) to 3 (perfect), considering whether the instruction conforms to the logic of navigation." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 45, + 706, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 706, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 706, + 279, + 730 + ], + "type": "text", + "content": "The results are presented in Table 4. It shows that our SODP scored 2.06 on Relevancy and 1.93 on Rational-" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 296, + 321, + 530, + 519 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 321, + 530, + 519 + ], + "spans": [ + { + "bbox": [ + 296, + 321, + 530, + 519 + ], + "type": "text", + "content": "ity, which could be considered acceptable since the highest score is 3 and it is challenging to generate instructions that are consistent with tasks and actual navigation logic. When removing the dynamic demonstration, the score of generated instruction drops about " + }, + { + "bbox": [ + 296, + 321, + 530, + 519 + ], + "type": "inline_equation", + "content": "31.55\\%" + }, + { + "bbox": [ + 296, + 321, + 530, + 519 + ], + "type": "text", + "content": " on Relevancy and " + }, + { + "bbox": [ + 296, + 321, + 530, + 519 + ], + "type": "inline_equation", + "content": "36.27\\%" + }, + { + "bbox": [ + 296, + 321, + 530, + 519 + ], + "type": "text", + "content": " on Rationality, which could also be observed in Fig. 6. Although the instruction generated without dynamic demonstration is related to the task to some extent (e.g., \"put the towel in the bottom drawer of the toilet\" has the keyword \"towel\", the instruction lacks navigation information, such as how to reach the bathroom.) As shown in the bottom example of Fig. 6, instruction without ROASP successfully guided how to go to the destination location kitchen, but it still caused confusion by going upstairs and going downstairs several times, and thus reducing the rationality score, i.e. 1.64 on Relevancy and 1.55 on Rationality. More generation results can be found in the supplementary." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 297, + 528, + 373, + 541 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 528, + 373, + 541 + ], + "spans": [ + { + "bbox": [ + 297, + 528, + 373, + 541 + ], + "type": "text", + "content": "6. Conclusions" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 296, + 548, + 530, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 548, + 530, + 676 + ], + "spans": [ + { + "bbox": [ + 296, + 548, + 530, + 676 + ], + "type": "text", + "content": "In this work, we propose a novel model, March-in-Chat (MiC), for the REVEIRE task, which only provides concise high-level instructions for the VLN agent. MiC enables the REVERIE agent to talk with an LLM on the fly to generate plans for the next few steps. It consists of three main modules, Goal-Oriented Static Planning (GOSP), Scene-Oriented Dynamic Planning (SODP), and Room-and-Object Aware Scene Perceiver (ROASP) module. We conduct extensive quantitative and qualitative experiments on REVERIE and the promising results show the effectiveness of our method." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 297, + 687, + 402, + 700 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 687, + 402, + 700 + ], + "spans": [ + { + "bbox": [ + 297, + 687, + 402, + 700 + ], + "type": "text", + "content": "7. Acknowledgements" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 297, + 706, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 706, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 297, + 706, + 530, + 730 + ], + "type": "text", + "content": "Jing Liu is supported by the National Key Research and Development Program of China (No. 2020AAA0106400)." + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "spans": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "type": "text", + "content": "15765" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 105, + 103, + 117 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 105, + 103, + 117 + ], + "spans": [ + { + "bbox": [ + 47, + 105, + 103, + 117 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 51, + 124, + 279, + 729 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 51, + 124, + 279, + 273 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 124, + 279, + 273 + ], + "spans": [ + { + "bbox": [ + 51, + 124, + 279, + 273 + ], + "type": "text", + "content": "[1] Michael Ahn, Anthony Brohan, Noah Brown, Yevgen Chebotar, Omar Cortes, Byron David, Chelsea Finn, Chuyuan Fu, Keerthana Gopalakrishnan, Karol Hausman, Alex Herzog, Daniel Ho, Jasmine Hsu, Julian Ibarz, Brian Ichter, Alex Irpan, Eric Jang, Rosario Jauregui Ruano, Kyle Jeffrey, Sally Jesmonth, Nikhil Joshi, Ryan Julian, Dmitry Kalashnikov, Yuheng Kuang, Kuang-Huei Lee, Sergey Levine, Yao Lu, Linda Luu, Carolina Parada, Peter Pastor, Jornell Quiambao, Kanishka Rao, Jarek Rettinghouse, Diego Reyes, Pierre Sermanet, Nicolas Sievers, Clayton Tan, Alexander Toshev, Vincent Vanhoucke, Fei Xia, Ted Xiao, Peng Xu, Sichun Xu, Mengyuan Yan, and Andy Zeng. Do as i can and not as i say: Grounding language in robotic affordances. In arXiv preprint arXiv:2204.01691, 2022. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 51, + 275, + 279, + 317 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 275, + 279, + 317 + ], + "spans": [ + { + "bbox": [ + 51, + 275, + 279, + 317 + ], + "type": "text", + "content": "[2] Dong An, Yuankai Qi, Yangguang Li, Yan Huang, Liang Wang, Tieniu Tan, and Jing Shao. Bevbert: Topo-metric map pre-training for language-guided navigation. arXiv preprint arXiv:2212.04385, 2022. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 51, + 319, + 279, + 372 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 319, + 279, + 372 + ], + "spans": [ + { + "bbox": [ + 51, + 319, + 279, + 372 + ], + "type": "text", + "content": "[3] Peter Anderson, Angel X. Chang, Devendra Singh Chaplot, Alexey Dosovitskiy, Saurabh Gupta, Vladlen Koltun, Jana Kosecka, Jitendra Malik, Roozbeh Mottaghi, Manolis Savva, and Amir Roshan Zamir. On evaluation of embodied navigation agents. CoRR, abs/1807.06757, 2018. 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 51, + 373, + 279, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 373, + 279, + 426 + ], + "spans": [ + { + "bbox": [ + 51, + 373, + 279, + 426 + ], + "type": "text", + "content": "[4] Peter Anderson, Qi Wu, Damien Teney, Jake Bruce, Mark Johnson, Niko Sünderhauf, Ian D. Reid, Stephen Gould, and Anton van den Hengel. Vision-and-language navigation: Interpreting visually-grounded navigation instructions in real environments. In CVPR, pages 3674-3683, 2018. 1, 2, 5" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 51, + 427, + 279, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 427, + 279, + 533 + ], + "spans": [ + { + "bbox": [ + 51, + 427, + 279, + 533 + ], + "type": "text", + "content": "[5] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, Sandhini Agarwal, Ariel Herbert-Voss, Gretchen Krueger, Tom Henighan, Rewon Child, Aditya Ramesh, Daniel Ziegler, Jeffrey Wu, Clemens Winter, Chris Hesse, Mark Chen, Eric Sigler, Mateusz Litwin, Scott Gray, Benjamin Chess, Jack Clark, Christopher Berner, Sam McCandlish, Alec Radford, Ilya Sutskever, and Dario Amodei. Language models are few-shot learners. In NeurIPS, pages 1877-1901, 2020. 3, 4" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 51, + 535, + 279, + 587 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 535, + 279, + 587 + ], + "spans": [ + { + "bbox": [ + 51, + 535, + 279, + 587 + ], + "type": "text", + "content": "[6] Angel X. Chang, Angela Dai, Thomas A. Funkhouser, Macej Halber, Matthias Nießner, Manolis Savva, Shuran Song, Andy Zeng, and Yinda Zhang. Matterport3d: Learning from RGB-D data in indoor environments. In 3DV, pages 667-676, 2017. 5" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 51, + 589, + 279, + 631 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 589, + 279, + 631 + ], + "spans": [ + { + "bbox": [ + 51, + 589, + 279, + 631 + ], + "type": "text", + "content": "[7] Howard Chen, Alane Suhr, Dipendra Misra, Noah Snavely, and Yoav Artzi. TOUCHDOWN: natural language navigation and spatial reasoning in visual street environments. In CVPR, pages 12538-12547, 2019. 1, 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 51, + 633, + 279, + 685 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 633, + 279, + 685 + ], + "spans": [ + { + "bbox": [ + 51, + 633, + 279, + 685 + ], + "type": "text", + "content": "[8] Mark Chen, Jerry Tworek, Heewoo Jun, Qiming Yuan, Henrique Ponde de Oliveira Pinto, Jared Kaplan, Harri Edwards, Yuri Burda, Nicholas Joseph, Greg Brockman, et al. Evaluating large language models trained on code. arXiv preprint arXiv:2107.03374, 2021. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 51, + 687, + 279, + 729 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 687, + 279, + 729 + ], + "spans": [ + { + "bbox": [ + 51, + 687, + 279, + 729 + ], + "type": "text", + "content": "[9] Shizhe Chen, Pierre-Louis Guhur, Cordelia Schmid, and Ivan Laptev. History aware multimodal transformer for vision-and-language navigation. In NeurIPS, pages 5834-5847, 2021. 7" + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 299, + 107, + 530, + 729 + ], + "type": "list", + "angle": 0, + "index": 24, + "blocks": [ + { + "bbox": [ + 299, + 107, + 530, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 107, + 530, + 149 + ], + "spans": [ + { + "bbox": [ + 299, + 107, + 530, + 149 + ], + "type": "text", + "content": "[10] Shizhe Chen, Pierre-Louis Guhur, Makarand Tapaswi, Cordelia Schmid, and Ivan Laptev. Learning from unlabeled 3d environments for vision-and-language navigation. In ECCV, 2022. 4, 6, 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 299, + 151, + 530, + 193 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 151, + 530, + 193 + ], + "spans": [ + { + "bbox": [ + 299, + 151, + 530, + 193 + ], + "type": "text", + "content": "[11] Shizhe Chen, Pierre-Louis Guhur, Makarand Tapaswi, Cordelia Schmid, and Ivan Laptev. Think global, act local: Dual-scale graph transformer for vision-and-language navigation. In CVPR, 2022. 2, 7" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 299, + 195, + 530, + 237 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 195, + 530, + 237 + ], + "spans": [ + { + "bbox": [ + 299, + 195, + 530, + 237 + ], + "type": "text", + "content": "[12] Chen Gao, Jinyu Chen, Si Liu, Luting Wang, Qiong Zhang, and Qi Wu. Room-and-object aware knowledge reasoning for remote embodied referring expression. In CVPR, pages 3064-3073, 2021. 7" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 299, + 239, + 530, + 280 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 239, + 530, + 280 + ], + "spans": [ + { + "bbox": [ + 299, + 239, + 530, + 280 + ], + "type": "text", + "content": "[13] Pierre-Louis Guhur, Makarand Tapaswi, Shizhe Chen, Ivan Laptev, and Cordelia Schmid. Airbert: In-domain pretraining for vision-and-language navigation. In ICCV, pages 1634-1643, 2021. 7" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 299, + 282, + 530, + 325 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 282, + 530, + 325 + ], + "spans": [ + { + "bbox": [ + 299, + 282, + 530, + 325 + ], + "type": "text", + "content": "[14] Keji He, Yan Huang, Qi Wu, Jianhua Yang, Dong An, Shuanglin Sima, and Liang Wang. Landmark-rxr: Solving vision-and-language navigation with fine-grained alignment supervision. NeurIPS, 34:652-663, 2021. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 299, + 326, + 530, + 369 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 326, + 530, + 369 + ], + "spans": [ + { + "bbox": [ + 299, + 326, + 530, + 369 + ], + "type": "text", + "content": "[15] Yicong Hong, Cristian Rodriguez Opazo, Qi Wu, and Stephen Gould. Sub-instruction aware vision-and-language navigation. In Bonnie Webber, Trevor Cohn, Yulan He, and Yang Liu, editors, EMNLP, pages 3360-3376, 2020. 5" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 299, + 370, + 530, + 412 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 370, + 530, + 412 + ], + "spans": [ + { + "bbox": [ + 299, + 370, + 530, + 412 + ], + "type": "text", + "content": "[16] Yicong Hong, Qi Wu, Yuankai Qi, Cristian Rodriguez Opazo, and Stephen Gould. VLN" + }, + { + "bbox": [ + 299, + 370, + 530, + 412 + ], + "type": "inline_equation", + "content": "\\text{©}" + }, + { + "bbox": [ + 299, + 370, + 530, + 412 + ], + "type": "text", + "content": " BERT: A recurrent vision-and-language BERT for navigation. In CVPR, pages 1643-1653, 2021. 2, 7" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 299, + 414, + 530, + 457 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 414, + 530, + 457 + ], + "spans": [ + { + "bbox": [ + 299, + 414, + 530, + 457 + ], + "type": "text", + "content": "[17] Wenlong Huang, Pieter Abbeel, Deepak Pathak, and Igor Mordatch. Language models as zero-shot planners: Extracting actionable knowledge for embodied agents. In ICML, pages 9118-9147. PMLR, 2022. 2, 3, 5" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 299, + 458, + 530, + 532 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 458, + 530, + 532 + ], + "spans": [ + { + "bbox": [ + 299, + 458, + 530, + 532 + ], + "type": "text", + "content": "[18] Wenlong Huang, Fei Xia, Ted Xiao, Harris Chan, Jacky Liang, Pete Florence, Andy Zeng, Jonathan Tompson, Igor Mordatch, Yevgen Chebotar, Pierre Sermanet, Noah Brown, Tomas Jackson, Linda Luu, Sergey Levine, Karol Hausman, and Brian Ichter. Inner monologue: Embodied reasoning through planning with language models. In arXiv preprint arXiv:2207.05608, 2022. 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 299, + 533, + 530, + 576 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 533, + 530, + 576 + ], + "spans": [ + { + "bbox": [ + 299, + 533, + 530, + 576 + ], + "type": "text", + "content": "[19] Vihan Jain, Gabriel Magalhães, Alexander Ku, Ashish Vaswani, Eugene Ie, and Jason Baldridge. Stay on the path: Instruction fidelity in vision-and-language navigation. pages 1862-1872, 2019. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 299, + 578, + 530, + 641 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 578, + 530, + 641 + ], + "spans": [ + { + "bbox": [ + 299, + 578, + 530, + 641 + ], + "type": "text", + "content": "[20] Melvin Johnson, Mike Schuster, Quoc V. Le, Maxim Krikun, Yonghui Wu, Zhifeng Chen, Nikhil Thorat, Fernanda B. Viégas, Martin Wattenberg, Greg Corrado, Macduff Hughes, and Jeffrey Dean. Google's multilingual neural machine translation system: Enabling zero-shot translation. Trans. Assoc. Comput. Linguistics, 5:339-351, 2017. 6" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 299, + 643, + 530, + 685 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 643, + 530, + 685 + ], + "spans": [ + { + "bbox": [ + 299, + 643, + 530, + 685 + ], + "type": "text", + "content": "[21] Alexander Ku, Peter Anderson, Roma Patel, Eugene Ie, and Jason Baldridge. Room-across-room: Multilingual vision-and-language navigation with dense spatiotemporal grounding. In EMNLP, pages 4392-4412, 2020. 1, 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 299, + 687, + 530, + 729 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 687, + 530, + 729 + ], + "spans": [ + { + "bbox": [ + 299, + 687, + 530, + 729 + ], + "type": "text", + "content": "[22] Jiachang Liu, Dinghan Shen, Yizhe Zhang, Bill Dolan, Lawrence Carin, and Weizhu Chen. What makes good in-context examples for gpt-3? arXiv preprint arXiv:2101.06804, 2021. 5" + } + ] + } + ], + "index": 23 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 747, + 300, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 747, + 300, + 756 + ], + "spans": [ + { + "bbox": [ + 277, + 747, + 300, + 756 + ], + "type": "text", + "content": "15766" + } + ] + } + ], + "index": 25 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 106, + 279, + 730 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 47, + 106, + 279, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 106, + 279, + 149 + ], + "spans": [ + { + "bbox": [ + 47, + 106, + 279, + 149 + ], + "type": "text", + "content": "[23] Chih-Yao Ma, Jiasen Lu, Zuxuan Wu, Ghassan AlRegib, Zsolt Kira, Richard Socher, and Caiming Xiong. Self-monitoring navigation agent via auxiliary progress estimation. In ICLR, 2019. 7" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 151, + 279, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 151, + 279, + 194 + ], + "spans": [ + { + "bbox": [ + 47, + 151, + 279, + 194 + ], + "type": "text", + "content": "[24] Khanh Nguyen and Hal Daumé III. Help, anna! visual navigation with natural multimodal assistance via retrospective curiosity-encouraging imitation learning. pages 684–695. Association for Computational Linguistics, 2019. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 195, + 279, + 237 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 195, + 279, + 237 + ], + "spans": [ + { + "bbox": [ + 47, + 195, + 279, + 237 + ], + "type": "text", + "content": "[25] Gabriel Poesia, Alex Polozov, Vu Le, Ashish Tiwari, Gustavo Soares, Christopher Meek, and Sumit Gulwani. Synchromesh: Reliable code generation from pre-trained language models. In ICLR, 2022. 5" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 239, + 279, + 292 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 239, + 279, + 292 + ], + "spans": [ + { + "bbox": [ + 47, + 239, + 279, + 292 + ], + "type": "text", + "content": "[26] Yuankai Qi, Zizheng Pan, Yicong Hong, Ming-Hsuan Yang, Anton van den Hengel, and Qi Wu. The road to knowwhere: An object-and-room informed sequential bert for indoor vision-language navigation. In ICCV, pages 1655-1664, 2021. 2, 7" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 293, + 279, + 346 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 293, + 279, + 346 + ], + "spans": [ + { + "bbox": [ + 47, + 293, + 279, + 346 + ], + "type": "text", + "content": "[27] Yuankai Qi, Qi Wu, Peter Anderson, Xin Wang, William Yang Wang, Chunhua Shen, and Anton van den Hengel. REVERIE: remote embodied visual referring expression in real indoor environments. In CVPR, pages 9979-9988, 2020. 1, 2, 6, 7" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 347, + 279, + 389 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 347, + 279, + 389 + ], + "spans": [ + { + "bbox": [ + 47, + 347, + 279, + 389 + ], + "type": "text", + "content": "[28] Yanyuan Qiao, Yuankai Qi, Yicong Hong, Zheng Yu, Peng Wang, and Qi Wu. HOP: history-and-order aware pretraining for vision-and-language navigation. In CVPR, pages 15397-15406, 2022. 2, 7" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 391, + 279, + 433 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 391, + 279, + 433 + ], + "spans": [ + { + "bbox": [ + 47, + 391, + 279, + 433 + ], + "type": "text", + "content": "[29] Yanyuan Qiao, Yuankai Qi, Yicong Hong, Zheng Yu, Peng Wang, and Qi Wu. Hop+: History-enhanced and order-aware pre-training for vision-and-language navigation. IEEE TPAMI, 2023. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 435, + 279, + 500 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 435, + 279, + 500 + ], + "spans": [ + { + "bbox": [ + 47, + 435, + 279, + 500 + ], + "type": "text", + "content": "[30] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, Gretchen Krueger, and Ilya Sutskever. Learning transferable visual models from natural language supervision. In ICML, volume 139, pages 8748-8763, 2021. 5" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 500, + 279, + 542 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 500, + 279, + 542 + ], + "spans": [ + { + "bbox": [ + 47, + 500, + 279, + 542 + ], + "type": "text", + "content": "[31] Alec Radford, Jeffrey Wu, Rewon Child, David Luan, Dario Amodei, Ilya Sutskever, et al. Language models are unsupervised multitask learners. OpenAI blog, 1(8):9, 2019. 3, 6" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 544, + 279, + 586 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 544, + 279, + 586 + ], + "spans": [ + { + "bbox": [ + 47, + 544, + 279, + 586 + ], + "type": "text", + "content": "[32] Nils Reimers and Iryna Gurevych. Sentence-bert: Sentence embeddings using siamese bert-networks. In Kentaro Inui, Jing Jiang, Vincent Ng, and Xiaojun Wan, editors, EMNLP-IJCNLP, pages 3980-3990, 2019. 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 588, + 279, + 640 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 588, + 279, + 640 + ], + "spans": [ + { + "bbox": [ + 47, + 588, + 279, + 640 + ], + "type": "text", + "content": "[33] Mohit Shridhar, Jesse Thomason, Daniel Gordon, Yonatan Bisk, Winson Han, Roozbeh Mottaghi, Luke Zettlemoyer, and Dieter Fox. ALFRED: A benchmark for interpreting grounded instructions for everyday tasks. In CVPR, pages 10737-10746, 2020. 1, 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 642, + 279, + 685 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 642, + 279, + 685 + ], + "spans": [ + { + "bbox": [ + 47, + 642, + 279, + 685 + ], + "type": "text", + "content": "[34] Ishika Singh, Valts Blukis, Arsalan Mousavian, Ankit Goyal, Danfei Xu, Jonathan Tremblay, Dieter Fox, Jesse Thomason, and Animesh Garg. ProgPrompt: Generating situated robot task plans using large language models. 2022. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 687, + 279, + 730 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 687, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 47, + 687, + 279, + 730 + ], + "type": "text", + "content": "[35] Chan Hee Song, Jiaman Wu, Clayton Washington, Brian M Sadler, Wei-Lun Chao, and Yu Su. Llm-planner: Few-shot grounded planning for embodied agents with large language models. arXiv preprint arXiv:2212.04088, 2022. 3, 5" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 299, + 106, + 530, + 280 + ], + "type": "list", + "angle": 0, + "index": 18, + "blocks": [ + { + "bbox": [ + 299, + 106, + 530, + 138 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 106, + 530, + 138 + ], + "spans": [ + { + "bbox": [ + 299, + 106, + 530, + 138 + ], + "type": "text", + "content": "[36] Jesse Thomason, Michael Murray, Maya Cakmak, and Luke Zettlemoyer. Vision-and-dialog navigation. In CoRL, pages 394-406, 2019. 1, 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 299, + 140, + 530, + 193 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 140, + 530, + 193 + ], + "spans": [ + { + "bbox": [ + 299, + 140, + 530, + 193 + ], + "type": "text", + "content": "[37] Xin Wang, Qiuyuan Huang, Asli Celikyilmaz, Jianfeng Gao, Dinghan Shen, Yuan-Fang Wang, William Yang Wang, and Lei Zhang. Reinforced cross-modal matching and self-supervised imitation learning for vision-language navigation. In CVPR, pages 6629-6638, 2019. 7" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 299, + 194, + 530, + 236 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 194, + 530, + 236 + ], + "spans": [ + { + "bbox": [ + 299, + 194, + 530, + 236 + ], + "type": "text", + "content": "[38] Yusheng Zhao, Jinyu Chen, Chen Gao, Wenguan Wang, Lirong Yang, Haibing Ren, Huaxia Xia, and Si Liu. Target-driven structured transformer planner for vision-language navigation. pages 4194-4203, 2022. 7" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 299, + 237, + 530, + 280 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 237, + 530, + 280 + ], + "spans": [ + { + "bbox": [ + 299, + 237, + 530, + 280 + ], + "type": "text", + "content": "[39] Fengda Zhu, Xiwen Liang, Yi Zhu, Qizhi Yu, Xiaojun Chang, and Xiaodan Liang. SOON: scenario oriented object navigation with graph-based exploration. In CVPR, pages 12689-12699, 2021. 1, 2" + } + ] + } + ], + "index": 17 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "spans": [ + { + "bbox": [ + 277, + 746, + 300, + 756 + ], + "type": "text", + "content": "15767" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Markov Game Video Augmentation for Action Segmentation/3ebb7b09-a6e7-4446-89ff-eb9741fd0b7f_content_list.json b/2023/Markov Game Video Augmentation for Action Segmentation/3ebb7b09-a6e7-4446-89ff-eb9741fd0b7f_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..0137158ca2b098464b3d0bce8625bc2e79f37fb0 --- /dev/null +++ b/2023/Markov Game Video Augmentation for Action Segmentation/3ebb7b09-a6e7-4446-89ff-eb9741fd0b7f_content_list.json @@ -0,0 +1,1498 @@ +[ + { + "type": "text", + "text": "Markov Game Video Augmentation for Action Segmentation", + "text_level": 1, + "bbox": [ + 179, + 130, + 790, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Nicolas Aziere", + "bbox": [ + 292, + 181, + 415, + 196 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Oregon State University", + "bbox": [ + 256, + 199, + 450, + 217 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "azieren@oregonstate.edu", + "bbox": [ + 251, + 219, + 457, + 232 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Sinisa Todorovic", + "bbox": [ + 550, + 181, + 687, + 196 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Oregon State University", + "bbox": [ + 522, + 199, + 714, + 217 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "sinisa@oregonstate.edu", + "bbox": [ + 521, + 219, + 718, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 268, + 313, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "This paper addresses data augmentation for action segmentation. Our key novelty is that we augment the original training videos in the deep feature space, not in the visual spatiotemporal domain as done by previous work. For augmentation, we modify original deep features of video frames such that the resulting embeddings fall closer to the class decision boundaries. Also, we edit action sequences of the original training videos (a.k.a. transcripts) by inserting, deleting, and replacing actions such that the resulting transcripts are close in edit distance to the ground-truth ones. For our data augmentation we resort to reinforcement learning, instead of more common supervised learning, since we do not have access to reliable oracles which would provide supervision about the optimal data modifications in the deep feature space. For modifying frame embeddings, we use a meta-model formulated as a Markov Game with multiple self-interested agents. Also, new transcripts are generated using a fast, parameter-free Monte Carlo tree search. Our experiments show that the proposed data augmentation of the Breakfast, GTEA, and 50Salads datasets leads to significant performance gains of several state of the art action segmenters.", + "bbox": [ + 75, + 301, + 472, + 632 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 662, + 209, + 679 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "This paper presents a new data augmentation framework for fully supervised action segmentation of untrimmed videos. Action segmentation is a basic vision problem. Despite recent tremendous advances in terms of new action segmenters and learning strategies, there is relatively slow progress in increasing the size of existing benchmark datasets. In comparison with peer datasets for action recognition or image classification, available benchmarks for action segmentation are significantly smaller. This presents challenges in training of recent action segmenters which show tendency to overfit on small datasets [11, 43, 40]. However, compiling large datasets is difficult, due to, in part, high costs of manual annotation of action segments.", + "bbox": [ + 75, + 688, + 468, + 885 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "We propose to augment existing datasets with newly gen", + "bbox": [ + 96, + 886, + 468, + 901 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "erated video sequences, such that the resulting data augmentation enables more robust training and hence improves performance of action segmenters. Our approach is agnostic of a particular model for action segmentation, and expects that the segmenter has been pre-trained on the original training dataset to predict action classes of video frames.", + "bbox": [ + 496, + 268, + 890, + 361 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Augmentation of video data has been mostly considered in the spatiotemporal, visual domain [38, 25, 19], where a human expert would heuristically specify the amount and type of data manipulation (e.g., subsampling, cropping, flipping of video frames) that are useful in training. While these approaches show great success, it is hard to formalize them in a principled manner. Others learn to generate new videos [9, 8, 42, 41], but the results are not sufficiently realistic yet, and hence would require domain adaptation if used for data augmentation in action segmentation.", + "bbox": [ + 496, + 364, + 892, + 516 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Our key novelty is that we augment the original training videos directly in the deep feature space, unlike most previous work. As shown in Fig. 1 (top left), for augmentation, we modify original deep features of video frames at the input, such that the resulting embeddings fall closer to the class decision boundaries. Thus, by construction, we enforce that the augmented features be more challenging for learning, and in this way subsequently enable more robust training of the action segmenter. In addition, Fig. 1 (top right) illustrates that we also edit action sequences of the original training videos (a.k.a. transcripts) by inserting, deleting, and replacing actions, such that the resulting transcripts are close in edit distance to the groundtruth ones. Since the generated transcripts are kept similar to the originals, they are expected to be meaningful (i.e., legal) and provide a greater variety of legal action sequences than seen in the original training set. This is especially important for those application domains where some transcripts of interest are naturally rare and hence underrepresented in the original training dataset.", + "bbox": [ + 496, + 518, + 893, + 821 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "For the proposed augmentation of frame embeddings in the deep feature space, we specify a deep residual metamodel, as shown in Fig. 1 (bottom left). The meta-model takes deep features of frames at the input and predicts an optimal amount of feature modifications - i.e., offset fea", + "bbox": [ + 496, + 824, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 805, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "13505", + "bbox": [ + 480, + 944, + 517, + 957 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/07e320007427c9b028287eb228d18bdca74202a43981638ece08e9a5d1256c40.jpg", + "image_caption": [ + "Figure 1. The proposed two-pronged data augmentation: (top and bottom left) Original deep features of frames at the input of a meta-model are modified to fall closer to class decision boundaries of the pretrained action segmenter. Alternative frameworks are considered for training the meta-model, including Gaussian noise, or supervised learning of a Temporal CNN, or reinforcement learning of an Actor-Critic network. (top and bottom right) The original action transcripts of training videos are modified by inserting, replacing, and removing actions, while ensuring a small edit distance between the newly generated transcripts and the originals. For training the meta-model for transcript augmentation, we consider supervised learning and alternatively a Monte Carlo tree search." + ], + "image_footnote": [], + "bbox": [ + 81, + 90, + 467, + 251 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "tures which are added to the original frame features, resulting in augmented embeddings. For training the meta-model, we consider both RL (Fig. 1 (bottom left)) and supervised learning. From our experiments, RL proves to be a more reliable paradigm.", + "bbox": [ + 75, + 446, + 467, + 521 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Supervised learning of the proposed meta-model faces a fundamental challenge. As a direct consequence of performing data augmentation in the deep feature space, there is no reliable oracle which would provide supervision for the optimal amount of feature modifications. The only available oracle is the pre-trained action segmentation model which could predict action labels of the augmented frame embeddings, and the incurred loss could be used for training the meta-model. The action segmentation model provides only pseudo-labels for generated data – not ground-truth labels – and hence a fully-supervised training of our meta-model could suffer from noisy pseudo-labels.", + "bbox": [ + 75, + 522, + 467, + 703 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "An alternative is to resort to reinforcement learning (RL) due to the following advantages. First, it allows us to sequentially modify frame features, where previous modifications define a state in which RL estimates an optimal modification of the next frames. Learning of the proposed sequential feature augmentation is expected to be more reliable, especially for long video sequences, than learning how to optimally modify all frame embeddings at once. RL produces an optimal policy which would account for temporal dependence between frame embeddings, and hence make them suitable for action segmentation models with large temporal receptive fields (like MS-TCN or AS-Former). Second, RL is expected to provide for a more sta", + "bbox": [ + 75, + 704, + 467, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "ble training of our meta-model by optimizing the expected reward over a policy of feature modifications, in comparison with the aforementioned minimization of the unreliable loss of the pretrained action segmenter on particular feature modifications. Third, RL is known to be very effective for problems with a large, continuous, output space, as is our case of predicting offset features in the deep feature space. Finally, RL is known to successfully address non-stationary environments with the distribution shift between training and test sets [37], which exactly characterizes our problem statement where data augmentation is aimed at bridging the distribution shift.", + "bbox": [ + 496, + 90, + 890, + 271 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Within the RL framework, for modifying frame embeddings, we formulate the meta-model as a Deep Actor-Critic Network for learning policies of two self-interested agents in a Markov Game. Also, for generating new transcripts, we use a fast, parameter-free Monte Carlo tree search. We call our approach Markov Game Video Augmentation (MVGA).", + "bbox": [ + 496, + 272, + 890, + 377 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Our experimental evaluation shows significant performance gains of recent convolutional and transformer-based action segmenters when our MVGA is used to augment the Breakfast, GTEA, and 50Salads datasets. Interestingly, MVGA enables the convolutional model MS-TCN [11, 27] achieve close performance to that of the significantly more complex (and more recent) ASFormer [43].", + "bbox": [ + 496, + 378, + 890, + 483 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In the following, Sec. 2 reviews closely related work, Sec. 3 gives an overview of MVGA, Sec. 4 specifies our transcript augmentation, Sec. 5 formalizes our frame-feature augmentation, and Sec. 6 presents our results.", + "bbox": [ + 496, + 483, + 890, + 544 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 558, + 640, + 573 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "This section reviews closely related work on fully supervised action segmentation and video data augmentation.", + "bbox": [ + 496, + 583, + 888, + 613 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "A family of temporal convolution models [10, 23, 24, 11, 40, 27, 34] have been studied for action segmentation. Some of these models use gradual temporal pooling for overcoming oversegmentation [10, 23, 24, 34], and others integrate reasoning about action boundaries [40, 18]. As representatives of this family, in our experiments, we consider MS-TCN [11, 27] and boundary-aware BCN [40] both of which consist of multiple stages of temporal convolution layers. Recent transformer-based models [43, 31, 39, 2] outperform temporal convolution models. Among these transformers, for evaluation, we consider ASFormer [43]. Both MS-TCN and ASFormer use standard I3D deep features [5]) of video frames as input. We also study a version of ASFormer with more informative frame embeddings [26].", + "bbox": [ + 496, + 613, + 890, + 824 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Video augmentation in the visible space-time domain, such as, e.g., temporal cropping of frames [38, 25] or random cropping/removing/flipping of frames in a training mini-batch [19] have become standard practice in action recognition, person re-ID, and hand gesture recogni", + "bbox": [ + 496, + 825, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "13506", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "tion. Other data augmentation methods have also been used, including pooling frame features within a window of variable length [34]. For video augmentation, some approaches generate simulated videos with video-game engines [9, 8], or GANs [14, 42, 41, 33]. However, there is still a large domain gap between such simulated and real videos, which limits the utility of these methods for data augmentation.", + "bbox": [ + 75, + 90, + 467, + 196 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Reinforcement learning has been used for addressing various vision problems, including 3D image segmentation [28, 32], image classification [29], object detection [3, 4], and tracking [6, 16]. To the best of our knowledge, video data augmentation for action segmentation has never been formulated within the reinforcement learning framework.", + "bbox": [ + 75, + 196, + 467, + 287 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Overview of MVGA", + "text_level": 1, + "bbox": [ + 76, + 303, + 267, + 318 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this and following two sections, we focus on our reinforcement learning formulation of the proposed data augmentation. The supervised learning formulation is described in Sec. 6. Fig. 2 shows an overview of our approach which consists of the following four steps. The first step pre-trains an action segmenter on a given training dataset $\\mathcal{D}$ . A training video of length $T$ in $\\mathcal{D}$ is given by its deep features for every frame $\\mathcal{X} = \\{x_t : t = 1, \\dots, T\\}$ , where $x_t \\in \\mathbb{R}^{d_{\\mathrm{in}}}$ ( $d_{\\mathrm{in}} = 2048$ for standard I3D features [5]), and the ground-truth action classes $\\mathcal{Y} = \\{y_t : t = 1, \\dots, T\\}$ , where $y_t \\in \\mathbb{Y}$ and $\\mathbb{Y}$ is a set of action classes. After pretraining, the action segmenter $f_{\\theta}$ can be used to predict action classes of video frames $\\hat{\\mathcal{Y}} = f(\\mathcal{X}; \\theta)$ .", + "bbox": [ + 75, + 329, + 467, + 525 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The second step generates new transcripts and their corresponding videos. We use the UCT algorithm [20] to first efficiently construct a tree, whose paths from the root to leaves represent legal transcripts, and then select optimal paths. For every new transcript, a new video is constructed by copying appropriate action segments from real videos in $\\mathcal{D}$ to the new video following the action sequence of the new transcript.", + "bbox": [ + 75, + 526, + 467, + 645 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The third step augments features of the original and new videos with the Actor and Critic networks, which gives the augmented dataset $\\mathcal{D}'$ . The Actor predicts how much and where to modify features in the input video. The Critic estimates the expected rewards for the Actor. Both Actor and Critic are learned using the pre-trained $f_{\\theta}$ as oracle.", + "bbox": [ + 75, + 647, + 467, + 737 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The fourth step fine-tunes $f_{\\theta}$ such that every mini-batch consists of videos from both $\\mathcal{D}$ and $\\mathcal{D}'$ .", + "bbox": [ + 75, + 738, + 467, + 767 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In the following, we specify the second and third steps.", + "bbox": [ + 96, + 768, + 460, + 784 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4. New Transcript and Video Generation", + "text_level": 1, + "bbox": [ + 76, + 799, + 421, + 815 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "From $\\mathcal{D}$ , we generate new transcripts and their corresponding new videos. The new transcripts should be semantically meaningful, i.e., legal. This is enforced by requiring that the new transcripts have: (i) similar lengths as the original transcripts; and (ii) high likelihoods of consec", + "bbox": [ + 75, + 825, + 467, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "utive pairs of action classes. Our experiments suggest that auto-regressive models - e.g., a recurrent-neural network (RNN) or Transformer network [35] - provide poor transcript generation, since they require large training datasets and hence have limited utility for our target settings where data augmentation is needed to address lack of data. Therefore, in this section, we focus on an alternative framework - parameter-free Monte-Carlo Tree Search (MTCS), where the space of transcripts is efficiently represented by a tree. We first construct the tree, and then identify its optimal path.", + "bbox": [ + 496, + 90, + 890, + 242 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4.1. MTCS for New Transcript Generation", + "text_level": 1, + "bbox": [ + 498, + 252, + 830, + 268 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In the tree of transcripts, the root represents the dummy \"start\" of action sequences. The root's descendants sequentially add action classes to the transcripts until leaf nodes, which represent the dummy \"end\". A node $v$ represents the last action class of the path $\\pi_v$ from the root to $v$ , $\\pi_v = \\{\\text{\"start\", } y_1, \\dots, y_v}\\}$ , where $y_v \\in \\mathbb{Y}$ or $y_v = \\text{\"end\"}$ if $v$ is a leaf node. Each node is assigned a weight, $w(v)$ , specified as the joint likelihood of the corresponding path:", + "bbox": [ + 496, + 276, + 890, + 397 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nw (v) = p \\left(\\left| \\pi_ {v} \\right|\\right) \\prod_ {\\left(u, u ^ {\\prime}\\right) \\in \\pi_ {v}} p \\left(y _ {u ^ {\\prime}} \\mid y _ {u}\\right), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 576, + 409, + 890, + 444 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $p(|\\pi_v|)$ is a prior of the transcript length, $u'$ is a child of $u$ along $\\pi_v$ , and $p(y_{u'} | y_u)$ denotes the transition probability of consecutive actions. In the special case, $p(y_{u'} | \"start\")$ and $p(\"end\" | y_u)$ represent the priors that the transcript begins and ends with classes $y_{u'}, y_u \\in \\mathbb{Y}$ . Both $p(|\\pi_v|)$ and $p(y_{u'} | y_u)$ are estimated from $\\mathcal{D}$ . For $p(|\\pi_v|)$ we learn the Poisson distribution, and for $p(y_{u'} | y_u)$ we estimate the frequency of the corresponding class transitions in $\\mathcal{D}$ .", + "bbox": [ + 496, + 455, + 890, + 575 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The tree is constructed iteratively using the well-known UCT algorithm [20] which balances a trade-off between exploitation and exploration. In each iteration, the root is sequentially expanded with a path of optimal descendants until the dummy \"end\" leaf or the maximum tree depth is reached. We do not allow illegal expansions, i.e., a path is guaranteed to consist of class transitions seen in $\\mathcal{D}$ . Suppose a path has reached node $u$ without meeting the stopping criterion. Then, UCT adds to the path the optimal node $u'$ from a subset of children, $\\mathrm{ch}(u) \\subset \\mathrm{Ch}(u) = \\{u': p(y_{u'} | y_u) > 0\\}$ :", + "bbox": [ + 496, + 577, + 890, + 729 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nu ^ {\\prime} = \\arg \\max _ {v \\in \\operatorname {c h} (u)} \\left[ w (v) + c \\sqrt {\\frac {2 \\log n (u)}{n (v)}} \\right] \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 557, + 739, + 890, + 781 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\operatorname{ch}(u)$ is randomly sampled $50\\%$ of $\\operatorname{Ch}(u)$ to enable exploring alternative paths; $w(v)$ is given by (1); $c = \\frac{1}{\\sqrt{2}}$ is the exploration-exploitation trade-off parameter; and $n(v)$ is the number of paths in the current tree that include node $v$ . As the tree iteratively grows, the value of $n(v)$ keeps changing for every node, which enables exploring less visited nodes in the space of transcripts even if $w(v)$ is small.", + "bbox": [ + 496, + 791, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "13507", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/a14584df1770b75c98816c93bbaa46f6a2becf24c61097e5214b864531491a21.jpg", + "image_caption": [ + "Figure 2. Our MVGA consists of four steps. 1-An action segmentation model is pre-trained using the original training set. 2-New transcripts are generated by selecting optimal paths in a UCT tree [20] of legal transcripts. For every new transcript, a new video is constructed by copying instances of action classes in the new transcript from real videos. 3- Features of the original and constructed new videos are augmented with the Actor and Critic networks. The Actor predicts the amount and location of feature modifications in the video. The Critic estimates the expected rewards for the Actor's two predictions. Both Actor and Critic are learned using the pre-trained action segmenter as oracle. 4- The action segmenter is fine-tuned on the original and augmented training videos." + ], + "image_footnote": [], + "bbox": [ + 163, + 88, + 810, + 338 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "After 1000 tree-growing iterations, the node $v^{*}$ with the highest likelihood $v^{*} = \\arg \\max_{v} w(v)$ in the tree uniquely identifies the newly generated transcript $\\pi_{v^{*}}$ . For generating another transcript, we construct another tree anew.", + "bbox": [ + 75, + 452, + 470, + 513 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.2. Generating New Videos of New Transcripts", + "text_level": 1, + "bbox": [ + 76, + 521, + 444, + 537 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Given a new transcript, $\\pi$ , we sequentially construct a new video with deep features (e.g., I3D [5]) following the ordering of action classes in $\\pi$ . It is worth emphasizing that our video generation occurs directly in the deep feature space. We begin by selecting a video $\\mathcal{X}_0 \\in \\mathcal{D}$ whose ground-truth transcript has the smallest edit distance to $\\pi$ . From $\\mathcal{X}_0$ , we remove all action segments that are not represented in $\\pi$ , resulting in our initial new video $\\mathcal{X}_0'$ . For action classes that are present in $\\pi$ but missing in $\\mathcal{X}_0'$ , we identify the second closest video $\\mathcal{X}_1 \\in \\mathcal{D}$ with these missing actions, and copy their respective temporal intervals to the appropriate locations in the new video, resulting in $\\mathcal{X}_1'$ . This is repeated until the entire $\\pi$ is fully represented by $\\mathcal{X}_g'$ , $g = 0, 1, 2, \\ldots$ . Note that $\\mathcal{X}_g'$ keeps the original lengths of action instances found in real videos, which ensures temporal coherence of every action in $\\mathcal{X}_g'$ . A pseudo-code of the proposed video generation is given in the supplement.", + "bbox": [ + 75, + 545, + 470, + 803 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "5. Augmentation of Frame Features", + "text_level": 1, + "bbox": [ + 76, + 815, + 380, + 832 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Features of both original and new videos are augmented by a Markov Game (MG) [15, 30, 37]. Since MG is a well-studied framework and we do not claim novelty in our particular formulation, below we rely that the reader is al-", + "bbox": [ + 75, + 839, + 470, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "ready familiar with the motivation and main concepts of MG. Our MG consists of two agents which sequentially take independent actions causing state changes of a fully observable environment. The environment at step $k$ is defined by state $s_k = (\\mathcal{X}_k, \\mathcal{M}_k)$ , where $\\mathcal{X}_k = \\{x_{k,t} : t = 1, \\dots, T\\}$ is the set of current video frame features, and $\\mathcal{M}_k = \\{m_{k,t} : t = 1, \\dots, T\\}$ is a binary mask assigned to the video frames, $m_{k,t} \\in \\{0,1\\}$ , for keeping the record which frames have been already modified. Given $s_k$ , the two agents follow their respective policies, $\\mu^1$ and $\\mu^2$ , to take actions $a_k^1 = \\mu^1(s_k) \\in \\mathcal{A}^1$ and $a_k^2 = \\mu^2(s_k) \\in \\mathcal{A}^2$ . $\\mathcal{A}^1$ is a continuous action space of agent 1, where $a_k^1 = \\{a_{t,k}^1 : t = 1, \\dots, T\\}$ represents the amount of feature augmentation, i.e., offset features. $\\mathcal{A}^2$ is a discrete action space of agent 2 for selecting video frames for augmentation, $a_k^2 \\in \\{0,1\\}^T$ , where $a_{t,k}^2 = 0$ means that the frame $t$ will not be augmented in step $k$ . $a_k^1$ and $a_k^2$ cause the environment to change to next state $s_{k+1}$ , which incurs the respective two rewards $R_k^1 = R^1(s_k, s_{k+1}, f_\\theta)$ and $R_k^2 = R^2(s_k, a_2^k)$ . Our goal is to learn $\\mu^1$ and $\\mu^2$ so as to maximize the agents' action-value functions given by:", + "bbox": [ + 496, + 452, + 893, + 773 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nQ ^ {i} (s, a) = \\mathbb {E} \\left[ \\sum_ {k \\geq 0} (\\gamma) ^ {k} R _ {k} ^ {i} \\mid \\mu^ {i}, a _ {0} ^ {i} = a, s _ {0} = s \\right], i = \\{1, 2 \\} \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 514, + 787, + 890, + 835 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbb{E}[\\cdot ]$ denotes expected value, $\\gamma = 0.99$ is the discount factor raised to the power of $k$ , $s\\in S$ , and $a\\in \\mathcal{A}^i$ .", + "bbox": [ + 496, + 837, + 890, + 867 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "For a given video, MG starts from the initial state $s_0 = (\\mathcal{X}_0, \\mathcal{M}_0)$ , with the original frame features and all-zero", + "bbox": [ + 500, + 869, + 893, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "13508", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "mask, $\\mathcal{X}_0 = \\mathcal{X}$ and $\\mathcal{M}_0 = \\{0\\}^T$ . In state $s_k$ , the two agents take their respective actions, which gives $s_{k + 1}$ specified as", + "bbox": [ + 76, + 90, + 468, + 122 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {X} _ {k + 1} = \\left\\{x _ {t, k} + a _ {t, k} ^ {2} \\left(a _ {t, k} ^ {1} + \\epsilon\\right): t = 1, \\dots , T \\right\\}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 109, + 131, + 467, + 148 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {M} _ {k + 1} = \\mathcal {M} _ {k} \\vee a _ {k} ^ {2}, \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 101, + 152, + 468, + 170 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\vee$ is the logical OR operator, and $\\epsilon \\in \\mathbb{R}^{d_{\\mathrm{in}}}$ is noise sampled from the zero-mean and unit-variance Gaussian distribution. $\\epsilon$ enables an exploration of $\\mathcal{A}^1$ and provides a way to generate multiple, distinct, augmented features from the same initial state $s_0$ . From (4), only frames selected by $a_k^2$ get updated with the corresponding offset features $(a_k^1 + \\epsilon)$ . Also, from (5), mask $\\mathcal{M}_k$ keeps the record of previously selected frames for augmentation.", + "bbox": [ + 76, + 179, + 468, + 301 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "MG stops as soon as one of the following happens (experimentally optimized): after $k = 10$ steps, or when $95\\%$ of the video has been augmented, $\\sum_{t=1}^{T} m_{t,k} \\geq 0.95T$ .", + "bbox": [ + 76, + 301, + 468, + 348 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.1. Two Rewards for Feature Augmentation", + "text_level": 1, + "bbox": [ + 76, + 354, + 421, + 371 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The policy of agent 1, $\\mu^1$ , is learned to augment original features, such that they become more challenging for the pre-trained action segmenter, $f_{\\theta}$ , and thus provide for a more robust subsequent training of $f_{\\theta}$ on the augmented training dataset. This is enforced by specifying the following reward $R_k^1 = R^1(s_k, s_{k+1}, f_{\\theta})$ . Let $\\hat{y}_t$ and $\\hat{y}_t'$ denote the top two scoring class predictions for $x_{t,k}$ by $f_{\\theta}$ , $\\hat{y}_t = \\arg \\max_{y \\in \\mathbb{Y}} p(y|x_{t,k};\\theta)$ and $\\hat{y}_t' = \\arg \\max_{y \\in \\mathbb{Y} \\setminus \\{\\hat{y}_t\\}} p(y|x_{t,k};\\theta)$ . We penalize agent 1 with a negative reward whenever $a_k^1$ causes $f_{\\theta}$ to make a wrong prediction, $\\hat{y}_t \\neq y_t$ . We assign a positive reward to agent 1 when $f_{\\theta}$ 's prediction is equal to the ground truth, $\\hat{y}_t = y_t$ , and reduce this positive reward if the feature augmentation is not challenging enough for $f_{\\theta}$ . The positive reward reduction is proportional to $f_{\\theta}$ 's confidence in its prediction, specified as a difference between its top two scoring predictions, $\\kappa = [p(\\hat{y}_t|x_{t,k};\\theta) - p(\\hat{y}_t'|x_{j,k};\\theta)]$ , $0 < \\kappa \\leq 1$ . Hence, when confidence $\\kappa$ is large and close to 1, the positive reward for agent 1 is maximally reduced as", + "bbox": [ + 76, + 378, + 468, + 667 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nR _ {k} ^ {1} = \\frac {1}{\\| a _ {k} ^ {2} \\|} \\sum_ {t \\in \\mathcal {T} (a _ {k} ^ {2})} r ^ {1} (x _ {t, k + 1}, f _ {\\theta}),\n$$\n", + "text_format": "latex", + "bbox": [ + 135, + 680, + 367, + 719 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nr ^ {1} \\left(x _ {t, k}, f _ {\\theta}\\right) = \\left\\{ \\begin{array}{l l} 1 - \\left[ p \\left(\\hat {y} _ {t} \\mid x _ {t, k}; \\theta\\right) - p \\left(\\hat {y} _ {t} ^ {\\prime} \\mid x _ {t, k}; \\theta\\right) \\right], & \\text {i f} \\hat {y} _ {t} = y _ {t} \\\\ - 1 & , \\text {i f} \\hat {y} _ {t} \\neq y _ {t} \\end{array} \\right. \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 78, + 719, + 470, + 792 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathcal{T}(a_k^2)$ returns the set of frames where $a_{t,k}^2 = 1$ .", + "bbox": [ + 76, + 792, + 426, + 809 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "For the policy of agent 2, $\\mu^2$ , we specify the following three requirements: (i) $\\mu^2$ should not select frames which have already been augmented in the previous MG steps; (ii) frame selection should be local at each MG step and focus only on a very few action instances in the video (and in this way make learning of $\\mu^1$ easier); and (iii) selected temporal", + "bbox": [ + 75, + 810, + 468, + 901 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "intervals should maximally overlap the ground-truth action instances. These three requirements are enforced by specifying the following reward:", + "bbox": [ + 498, + 90, + 890, + 137 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nR _ {k} ^ {2} = \\left\\{ \\begin{array}{c} \\sum_ {\\tau} \\frac {| \\tau \\cap a _ {k} ^ {2} |}{| \\tau |}, \\text {i f} \\sum_ {t} a _ {t, k} ^ {2} m _ {t, k} < \\alpha \\text {a n d} \\| a _ {k} ^ {2} \\| < \\frac {T}{2} \\\\ - 1, \\text {o t h e r w i s e} \\end{array} \\right. \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 504, + 147, + 890, + 229 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "$\\tau$ is the ground-truth mask of actions over frames, and enforces that each iteration of the video augmentation covers the entire time interval of an action rather than randomly scattered frames. $\\alpha = 0.4T$ is an experimentally optimized threshold which allows a flexible frame selection of up to $40\\%$ of the past $\\mathcal{M}_k$ . From (7), agent 2 is penalized when selects more than a half of the video for augmentation.", + "bbox": [ + 496, + 229, + 890, + 335 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.2. Learning the Policies for Feature Augmentation", + "text_level": 1, + "bbox": [ + 498, + 345, + 890, + 362 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To learn $\\mu^1$ and $\\mu^2$ , we design an Actor-Critic model with a decentralized-actor deep network for computing the agents' actions, and a centralized-critic deep network for efficiently estimating action-value functions $\\hat{Q}^1$ and $\\hat{Q}^2$ , as shown in Fig. 3. The Actor-Critic framework has been demonstrated effective for continuous agent-action spaces and when the agents have individual rewards [17], as in our case. In general, decentralizing the actor network helps increase stationarity of environments with self-interested agents [37]. The centralized critic network is suitable because it allows relevant information from all of the agents to be shared toward estimating each agent's expected reward.", + "bbox": [ + 496, + 368, + 890, + 549 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "As can be seen in Fig. 3, the input to the actor network, $s_k = (\\mathcal{X}_k, \\mathcal{M}_k)$ , is passed through a backbone, specified as a multi-stage temporal convolutional neural network (TCN) [11], in order to estimate the latent (deep) representation of $s_k$ . Then, two distinct 1-stage TCNs take this latent representation as input and compute the frame selection", + "bbox": [ + 498, + 550, + 890, + 641 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/ac11775c1bb28e9621f1c50e5b0fac05631f9f124203b8fe256f102618230d56.jpg", + "image_caption": [ + "Figure 3. Actor-Critic model for learning policies $\\mu^1$ and $\\mu^2$ consists of several stages of temporal convolution network (TCN). The actor network predicts feature augmentation, and the centralized critic estimates the expected rewards for each policy." + ], + "image_footnote": [], + "bbox": [ + 504, + 662, + 890, + 828 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "13509", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "$a_2^k$ and feature offsets of the selected frames $a_k^1$ . Finally, the predicted $a_k^1$ , $a_2^k$ , and latent feature of $s_k$ are passed to the centralized critic - specifically, a 2-stage TCN - to estimate the expected rewards $\\hat{Q}_k^1 = \\hat{Q}^1 (s_k,a_k^1,a_k^2)$ and $\\hat{Q}_k^2 = \\hat{Q}^2 (s_k,a_k^1,a_k^2)$ of $\\mu^1$ and $\\mu^2$ .", + "bbox": [ + 76, + 90, + 467, + 169 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Parameters of the proposed actor-critic deep architecture are learned using the standard temporal difference learning [21]. The critic learns to iteratively simulate the action-value function, $\\hat{Q}_k^i$ , $i = \\{1, 2\\}$ , which is later used to update parameters of the actor network. To this end, we minimize the following loss of the critic network:", + "bbox": [ + 76, + 169, + 467, + 258 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\nL _ {C} = \\sum_ {i \\in \\{1, 2 \\}} \\left(R _ {k} ^ {i} + \\gamma \\hat {Q} _ {k + 1} ^ {i} - \\hat {Q} _ {k} ^ {i}\\right) ^ {2}, \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 143, + 271, + 467, + 310 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $R_{k}^{i}$ is given by (6) and (7), and $\\gamma$ is the discount factor. The actor network is learned with the following loss:", + "bbox": [ + 76, + 324, + 467, + 354 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\nL _ {A} ^ {i} = \\left\\| a _ {k} ^ {i} \\right\\| _ {2} ^ {2} \\cdot \\left(R _ {k} ^ {i} + \\gamma \\hat {Q} _ {k + 1} ^ {i} - \\hat {Q} _ {k} ^ {i}\\right) ^ {2}, i = \\{1, 2 \\}. \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 91, + 378, + 467, + 407 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "A proof in [37] shows that minimizing $L_{C}$ and $L_{A}$ in (8) and (9) optimizes $\\mu^{1}$ and $\\mu^{2}$ so they manage to achieve maximal rewards $R^{1}$ and $R^{2}$ given by (6) and (7), as desired.", + "bbox": [ + 76, + 417, + 467, + 464 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "6. Results", + "text_level": 1, + "bbox": [ + 76, + 479, + 161, + 494 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Datasets include three benchmarks: Breakfast [22], GTEA [12], and 50Salads [36]. For each dataset, we precompute the standard I3D frame features without any self-supervision, fine-tuning, or data augmentation, as in [11]. Breakfast has 1712 videos with 48 action classes, GTEA shows 7 complex activities, each specified in terms of 11 action classes including the background class. 50Salads consists of 50 videos with 17 action classes. For Breakfast, GTEA, and 50Salads, we perform the standard 4-fold, 4-fold, and 5-fold cross validation, respectively.", + "bbox": [ + 75, + 506, + 467, + 656 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Metrics. Mean-of-Frame (MoF) is the average framework classification accuracy. Edit score counts edit operations to make the predicted and ground-truth sequences equivalent. F1 score counts true positives when a temporal intersection between the predicted and ground-truth segments is $10\\%$ , $25\\%$ and $50\\%$ , denoted as F1@10,25,50.", + "bbox": [ + 75, + 657, + 467, + 747 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Implementation details. The Actor-Critic has the same layers as MS-TCN [11]. One stage consists of 10 convolution layers with an increasing dilation rate and feature maps with size 128. The mask backbone and feature backbone each represents a 1-stage TCN. Their outputs are, first, concatenated, then, passed to a 4-stage MS-TCN, and, finally, input to the agents' heads. Agent 1's head is a 2-stage MS-TCN. Agent 2's head is a 1-stage TCN. The critic network is a 2-stage MS-TCN. The learning rate for the actor-critic training is 0.0001. Our training of the meta-model is run for", + "bbox": [ + 75, + 750, + 467, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "30 epochs. The NMS threshold is set to 0.5, and the minimum IOU is set to 0. The discount factor $\\gamma = 0.99$ . The policy training on Tesla-V100s for GTEA takes 3 hours. The MCTS algorithm runs 1000 node expansions in a couple of seconds. The maximum tree width is 200. The maximum tree depth is $\\hat{\\lambda} + 2\\sqrt{\\hat{\\lambda}}$ where $\\hat{\\lambda}$ is the average transcript length of the training set. The number of epochs in the fine-tuning on the original and augmented data is 50 epochs for MS-TCN, 100 epochs for ASFormer, and 50 epochs for BCN. The meta-training of the meta-model increases complexity compared to baseline approaches. It is important to separate the time for training an action segmentation model, and the time for our meta-training. Our meta-training can be viewed as a part of the dataset preparation, which takes significantly less time than manually collecting and annotating real videos.", + "bbox": [ + 496, + 90, + 890, + 335 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "6.1. Ablation Studies of MS-TCN on GTEA", + "text_level": 1, + "bbox": [ + 498, + 347, + 834, + 361 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The training dataset size. Tab. 1 reports how MS-TCN performance on GTEA changes as a function of two variables: (i) the number of training transcripts; and (ii) the total number of original and augmented videos – both expressed as the increase factor of the original set. Tab. 1 shows that when the original set of training videos is tripled such that there are $20\\%$ of new transcripts, MS-TCN achieves the best performance for all of the metrics, and this setting is used in the sequel. Too many augmentations using the same input video leads to similar data outputs, and consequently to overfitting in training of an action segmentation model. Note that testing the transcript augmentation as a standalone contribution is inappropriate and reduces performance (second row), since new transcripts need to be realized as new videos. These new videos are Frankenstein-like constructs from multiple real videos, and hence have highly unrealistic action transitions, and incoherent and sometimes impossible human motions. Therefore, the new videos require additional frame-feature augmentation to provide useful data augmentation.", + "bbox": [ + 496, + 369, + 890, + 672 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Alternatives for generating transcripts. Tab. 2 compares two alternative methods for generating transcripts – namely, auto-regression and our UCT – in terms of: (i) edit distance to the ground-truth transcripts, and (ii) expected reward given by (1). The two metrics are averaged over the top $10\\%$ and $20\\%$ of generated transcripts that are the closest to the ground-truth transcripts. The auto-regressive model is a Transformer Network [35] trained with the cross-entropy loss to predict the next action class given an input sequence of action classes. From Tab. 2, our UCT generates transcripts which are more similar to the ground-truth ones than those produced by auto-regression. Also, the average likelihoods for UCT and ground truth are nearly the same.", + "bbox": [ + 496, + 674, + 890, + 869 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "RL vs Non-RL for frame-feature augmentation. Tab. 3 compares the proposed reinforcement learning and", + "bbox": [ + 500, + 869, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "13510", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/e12669ff5e0d47930af944168521ff2a337ed9ad9b72b9be0fb85e408a3edd73.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
#TranscriptsTrain. set sizeF1@10,25,50EditMoF
1×1×87.384.972.482.078.0
1.1×1×85.281.169.780.074.9
1×2×89.888.577.686.879.5
1.1×2×90.588.677.987.178.9
1.2×3×90.988.279.288.879.6
1.2×4×89.187.778.989.079.7
1.2×5×89.087.075.685.778.2
", + "bbox": [ + 78, + 88, + 475, + 189 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/4ef8915bd572855a453fb0e2969c189e1063f4845830b2083a81c297b69e35df.jpg", + "table_caption": [ + "Table 1. MS-TCN performance on GTEA as a function of the number of training transcripts, and the number of original and augmented videos used for training -both expressed as the increase factor of the original training set. When our augmentation triples the set of training videos such that there are $20\\%$ of newly generated transcripts, MS-TCN achieves the best performance. The top row is without any augmentation, and the second from the top row is for only feature augmentation without new transcripts." + ], + "table_footnote": [], + "table_body": "
MethodEdit dist. (%) Top 10%Edit dist. (%) Top 20%Likelihood Top 20%
Auto-regression19.522.00.59e-4
UCT14.015.21.41e-4
Ground truth--1.45e-4
", + "bbox": [ + 78, + 319, + 478, + 395 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/f8be5464269410f877c8420388098a97267602f30fb4ada525552eade1a2f2c0.jpg", + "table_caption": [ + "Table 2. Comparison of two alternative transcript generation methods – auto-regression by a Transformer Network [35], and our proposed UCT – in terms of an average edit distance between the generated and ground-truth transcripts for GTEA, and their average likelihood given by (1). The two metrics are averaged over the top $10\\%$ and $20\\%$ of generated transcripts closest to the ground-truth." + ], + "table_footnote": [], + "table_body": "
Frame AugmentationF1@10,25,50EditMoF
No augmentation [11]85.883.469.879.076.3
Noise85.783.271.979.677.5
Non-RL (Seq)83.180.969.176.276.5
Non-RL (All)83.981.570.477.677.7
Our RL-based90.988.279.288.879.6
", + "bbox": [ + 80, + 494, + 460, + 584 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/2cb39568cf66c71f10e0c6e024b9f151a647905adbae1a539b62d1c3c7237be3.jpg", + "table_caption": [ + "Table 3. MS-TCN performance on GTAE, when using the best data augmentation setting given in Tab. 1, and for alternative strategies of frame-feature augmentation. Supervised learning in \"Non-RL\" decreases the performance of MS-TCN." + ], + "table_footnote": [], + "table_body": "
PoliciesF1@10,25,50EditMoF
μ1/1088.585.074.783.878.2
μ1/2087.484.874.184.577.8
μ1/μ290.988.279.288.879.6
", + "bbox": [ + 122, + 652, + 419, + 710 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "an alternative supervised learning for frame-feature augmentation, when using the best data augmentation setting given in Tab. 1. We consider several baselines. \"Noise\" refers to simply adding Gaussian noise with zero mean and 0.01 variance to the original deep features of frames, as the original I3D features have an average value of 0.2 and variance 0.06. From Tab. 3, such a frame-feature augmentation with Gaussian noise barely has any effect on MS-TCN's performance. \"Non-RL\" is another baseline that uses su", + "bbox": [ + 75, + 763, + 468, + 900 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/c36c5953fc693afcf6a3f761bd11afd17e2e4a5dbbf664251cc42945dc3c3406.jpg", + "table_caption": [ + "Table 4. MS-TCN performance on GTAE for the proposed multiagent $(\\mu_{1} / \\mu_{2})$ and the alternative single-agent $(\\mu_{1} / 10$ or $\\mu_{1} / 20)$" + ], + "table_footnote": [], + "table_body": "
Class transition2, 52, 75, 98, 1010, 4
# Original dataset11233
# Augmented dataset22355
", + "bbox": [ + 509, + 88, + 879, + 132 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 5. Count of the least represented action transitions in the original and augmented training sets of GTEA.", + "bbox": [ + 500, + 132, + 890, + 159 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "pervised learning for training the meta-model, as depicted in Fig. 1 (bottom left). In \"Non-RL\" the meta-model is a 1-stage TCN which outputs the offset feature for a given original feature at the input. As shown in Fig. 1 (bottom left), the resulting augmented feature is then passed to the pre-trained action segmenter. The meta-model is trained based on the cross-entropy loss of the pre-trained action segmenter, which serves as an oracle to ensure that the augmented feature remains in the action class of the original frame feature. For \"Non-RL\", we also regularize the resulting augmented feature to be different from the original feature with the standard contrastive loss. Moreover, we study two versions of \"Non-RL\" - one where all features of the entire video are modified at once, called \"Non-RL (All)\"; and the other with a sequential modification of frame features one action segment at a time, called \"Non-RL (Seq)\" From Tab. 3, both \"Non-RL (All)\" and \"Non-RL (Seq)\" decrease MS-TCN's performance. More details on \"Non-RL\" are presented in the supplement.", + "bbox": [ + 496, + 185, + 890, + 472 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Policy. Tab. 4 compares MS-TCN performance on GTAE for our multi-agent formulation and an alternative single-agent feature augmentation. The latter does not learn frame masking, and hence does not have our agent 2. The single-agent, denoted as $\\mu_1 / 10$ or $\\mu_1 / 20$ , uses only policy $\\mu_1$ for augmenting frame features. The values 10 and 20 indicate the percent of video randomly selected for augmentation at each policy iteration. Our multi-agent, denoted as $\\mu_1 / \\mu_2$ , uses both $\\mu_1$ and $\\mu_2$ policies. Tab. 4 shows that adding the second agent significantly improves the results.", + "bbox": [ + 496, + 472, + 890, + 625 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Improving transcripts variability. Generating new transcripts modify the total count of action transition initially present in the original set of transcripts. The advantage of our MCTS based generation approach is the emphasis on exploration. The number of poorly represented action transitions are increased with the new transcripts in training. Tab. 5 shows some example action transitions that are the least represented in the original training set get at least one new instance when adding the generated transcripts.", + "bbox": [ + 496, + 625, + 890, + 760 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "6.2. Impact of MVGA on SOTA", + "text_level": 1, + "bbox": [ + 500, + 771, + 745, + 787 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "The top of Tab. 6 reports results of state-of-the-art (SOTA) fully supervised methods that do not use video augmentation in training (some of them use sophisticated post-processing, which we do not have). Tab. 6 also shows how MVGA affects performance of SOTA approaches – including: MS-TCN[11], BCN [40], ASFormer [43], and BridgePrompt [26] – on Breakfast, GTAE, and 50Salads. As can", + "bbox": [ + 496, + 794, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "13511", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/23fce50eacc8a6e3ae4e6e352f16f754cb7a4d943a77e8324f7d44a6947d232c.jpg", + "table_caption": [], + "table_footnote": [ + "Table 6. Impact of MVGA on SOTA methods on Breakfast, GTEA and 50Salads, and comparison with the other SOTA approaches that do not use data augmentation." + ], + "table_body": "
DatasetBreakfastGTEA50Salads
MethodF1@10,25,50EditMoFF1@10,25,50EditMoFF1@10,25,50EditMoF
MSTCN++ [27]64.158.645.965.667.687.886.274.482.678.980.778.570.174.383.7
ASRF [18]74.368.956.172.467.689.487.879.883.777.384.983.577.379.384.5
HASR [1]74.769.557.071.969.489.287.274.884.576.986.685.778.581.083.9
SSTDA [7]75.069.155.273.770.290.089.178.086.279.883.081.573.875.883.2
G2L [13]74.969.055.273.370.789.987.375.884.678.580.378.069.873.482.2
UVAST [2]76.770.056.668.286.277.169.754.290.562.281.270.483.977.169.7
MSTCN [11]52.648.137.961.766.385.883.469.879.076.376.374.064.567.980.7
MSTCN (Ours)58.154.644.463.466.887.384.972.482.078.075.873.866.868.282.7
MSTCN + MVGA68.966.155.868.171.190.988.879.288.279.680.177.971.274.183.2
BCN [40]68.765.555.066.270.488.587.177.384.479.882.381.374.074.384.4
BCN + MVGA70.867.757.368.371.891.390.080.686.780.583.782.475.877.285.6
ASFormer [43]76.070.657.475.073.590.188.879.284.679.785.183.476.079.685.6
ASFormer + MVGA75.672.159.776.874.291.390.579.386.480.386.384.978.781.386.0
Bridge-Prompt [26]94.192.083.091.681.289.287.881.383.888.1
Bridge-Prompt + MVGA95.293.484.892.182.690.889.483.286.188.9
", + "bbox": [ + 81, + 88, + 888, + 297 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/e413f947d2bd87bbe4ebb7b0c375a09cfd216dd116a4d778d698e0982187e5fd.jpg", + "table_caption": [], + "table_footnote": [ + "Table 7. Comparison of different data augmentation methods on Breakfast, GTEA and 50Salads." + ], + "table_body": "
DatasetBreakfastGTEA50Salads
MethodF1@10,25,50EditMoFF1@10,25,50EditMoFF1@10,25,50EditMoF
MSTCN + C2F[34]58.255.047.862.966.586.283.578.178.876.577.374.265.567.380.8
MSTCN + Speed55.052.741.960.165.984.880.866.178.875.777.375.967.868.881.2
MSTCN + MVGA68.966.155.868.171.190.988.879.288.279.680.177.971.274.183.2
ASFormer + C2F [34]75.872.357.575.272.990.388.078.884.278.984.582.676.178.784.0
ASFormer + Speed75.269.156.974.871.989.387.277.785.278.584.482.975.177.285.1
ASFormer + MVGA75.672.159.776.874.291.390.579.386.480.386.384.978.781.386.0
", + "bbox": [ + 88, + 338, + 880, + 438 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "be seen, for all of the four SOTA approaches, data augmentation by MVGA consistently produces performance gains relative to their respective performance without data augmentation. For instance, MSTCN+MVGA outperforms both MSTCN [11] and its more advanced relative MSTCN++ [27] without data augmentation. MVGA also improves the original ASFormer [43] producing the new state of the art performance on Breakfast. Applying MVGA on the features provided by Bridge-Prompt [26] and following the same training procedure as for the ASFormer gives the method Bridge-Prompt+MVGA with the best results on GTAE and 50Salads. In Tab. 6, we could not report Bridge-Prompt+MVGA performance on Breakfast, since the Bridge-Prompt model for action segmentation on Breakfast is not publicly available, and our own training of Bridge-Prompt on Breakfast gave poor results.", + "bbox": [ + 80, + 474, + 468, + 717 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Video augmentation has been considered in the context of self-supervised learning (typically as a part of pretraining). However, a comparison with such methods is beyond our scope, because MVGA directly allows for the unified fully supervised training on a larger, augmented training dataset. In Tab. 7, we compare MVGA with some baseline video augmentation methods which also directly enable fully supervised learning, including Speed and C2F [34]. The former randomly selects certain action instances in each original training video, and performs \"speeding-up\" (i.e., frame subsampling) or \"slowing-down\" (i.e., frame upsampling with interpolation) of their temporal intervals,", + "bbox": [ + 80, + 719, + 468, + 900 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "and thus doubles the original training set. C2F randomly selects certain time intervals in every original training video. Then, for each selected interval, C2F assigns the dominant ground-truth action class with the largest temporal support in that interval, and also replaces all frame features within the interval with their max-pooled feature. As can be seen in Tab. 7, MVGA provides for better data augmentation for MS-TCN and ASFormer than Speed and C2F.", + "bbox": [ + 500, + 474, + 890, + 597 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "7. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 625, + 617, + 638 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We have specified video data augmentation for action segmentation within the reinforcement learning framework. Our approach generates new action transcripts and their corresponding new videos, as well as modifies the feature embedding of video frames. The transcript generation uses the efficient Monte-Carlo Tree Search to produce new, legal, high-likelihood action sequences. Optimal amount and temporal locations of feature changes in the video are learned with a two-agent actor-critic network. Our video augmentation in training of representative, state-of-the-art, convolutional and transformer-based action segmenters leads to their significant performance gains on the benchmark Breakfast, GTEA, and 50salads datasets, in comparison to their original training without video augmentation.", + "bbox": [ + 500, + 654, + 890, + 866 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgments This work was supported in part by DARPA MCS Award N66001-19-2-4035.", + "bbox": [ + 500, + 869, + 890, + 898 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "13512", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Hyemin Ahn and Dongheui Lee. Refining action segmentation with hierarchical video representations. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 16302-16310, 2021.", + "[2] Nadine Behrmann, S Alireza Golestaneh, Zico Kolter, Juergen Gall, and Mehdi Noroozi. Unified fully and timestamp supervised temporal action segmentation via sequence to sequence translation. arXiv preprint arXiv:2209.00638, 2022.", + "[3] Miriam Bellver Bueno, Xavier Giro-i Nieto, Ferran Marqués, and Jordi Torres. Hierarchical object detection with deep reinforcement learning. Deep Learning for Image Processing Applications, 31(164):3, 2017.", + "[4] Juan C Caicedo and Svetlana Lazebnik. Active object localization with deep reinforcement learning. In Proceedings of the IEEE international conference on computer vision, pages 2488-2496, 2015.", + "[5] Joao Carreira and Andrew Zisserman. Quo vadis, action recognition? a new model and the kinetics dataset. In CVPR, 2017.", + "[6] Boyu Chen, Dong Wang, Peixia Li, Shuang Wang, and Huchuan Lu. Real-time actor-critic tracking. In Proceedings of the European conference on computer vision (ECCV), pages 318-334, 2018.", + "[7] Min-Hung Chen, Baopu Li, Yingze Bao, Ghassan Al-Regib, and Zsolt Kira. Action segmentation with joint self-supervised temporal domain adaptation. In CVPR, 2020.", + "[8] César Roberto de Souza, Adrien Gaidon, Yohann Cabon, Naila Murray, and Antonio Manuel López. Generating human action videos by coupling 3d game engines and probabilistic graphical models. International Journal of Computer Vision, 128(5):1505-1536, 2020.", + "[9] César Roberto de Souza12, Adrien Gaidon, Yohann Cabon, and Antonio Manuel López. Procedural generation of videos to train deep action recognition networks. 2017.", + "[10] Li Ding and Chenliang Xu. Weakly-supervised action segmentation with iterative soft boundary assignment. In CVPR, June 2018.", + "[11] Yazan Abu Farha and Jurgen Gall. MS-TCN: Multi-stage temporal convolutional network for action segmentation. In CVPR, 2019.", + "[12] Alireza Fathi, Xiaofeng Ren, and James M Rehg. Learning to recognize objects in egocentric activities. In CVPR 2011, pages 3281-3288. IEEE, 2011.", + "[13] Shang-Hua Gao, Qi Han, Zhong-Yu Li, Pai Peng, Liang Wang, and Ming-Ming Cheng. Global2local: Efficient structure search for video action segmentation. In CVPR, 2021.", + "[14] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. Communications of the ACM, 63(11):139-144, 2020.", + "[15] Junling Hu and Michael P Wellman. Nash q-learning for general-sum stochastic games. Journal of machine learning research, 4(Nov):1039-1069, 2003.", + "[16] Chen Huang, Simon Lucey, and Deva Ramanan. Learning policies for adaptive tracking with deep feature cascades. In" + ], + "bbox": [ + 78, + 114, + 470, + 901 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Proceedings of the IEEE international conference on computer vision, pages 105-114, 2017.", + "[17] Shariq Iqbal and Fei Sha. Actor-attention-critic for multiagent reinforcement learning. In International conference on machine learning, pages 2961–2970. PMLR, 2019.", + "[18] Yuchi Ishikawa, Seito Kasai, Yoshimitsu Aoki, and Hirokatsu Kataoka. Alleviating over-segmentation errors by detecting action boundaries. In WACV, 2021.", + "[19] Takashi Isobe, Jian Han, Fang Zhuz, Yali Liy, and Shengjin Wang. Intra-clip aggregation for video person re-identification. In 2020 IEEE International Conference on Image Processing (ICIP), pages 2336-2340. IEEE, 2020.", + "[20] Levente Kocsis and Csaba Szepesvári. Bandit based montecarlo planning. In European conference on machine learning, pages 282-293. Springer, 2006.", + "[21] Vijay Konda and John Tsitsiklis. Actor-critic algorithms. Advances in neural information processing systems, 12, 1999.", + "[22] Hilde Kuehne, Ali Arslan, and Thomas Serre. The language of actions: Recovering the syntax and semantics of goal-directed human activities. In CVPR, 2014.", + "[23] Colin Lea, Michael D. Flynn, Rene Vidal, Austin Reiter, and Gregory D. Hager. Temporal convolutional networks for action segmentation and detection. In CVPR, 2017.", + "[24] Peng Lei and Sinisa Todorovic. Temporal deformable residual networks for action segmentation in videos. In CVPR, 2018.", + "[25] Jie Li, Mingqiang Yang, Yupeng Liu, Yanyan Wang, Qinghe Zheng, and Deqiang Wang. Dynamic hand gesture recognition using multi-direction 3d convolutional neural networks. Engineering Letters, 27(3), 2019.", + "[26] Muheng Li, Lei Chen, Yueqi Duan, Zhilan Hu, Jianjiang Feng, Jie Zhou, and Jiwen Lu. Bridge-prompt: Towards ordinal action understanding in instructional videos. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 19880-19889, 2022.", + "[27] Shi-Jie Li, Yazan AbuFarha, Yun Liu, Ming-Ming Cheng, and Juergen Gall. MS-TCN++: Multi-stage temporal convolutional network for action segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020.", + "[28] Xuan Liao, Wenhao Li, Qisen Xu, Xiangfeng Wang, Bo Jin, Xiaoyun Zhang, Yanfeng Wang, and Ya Zhang. Iteratively-refined interactive 3d medical image segmentation with multi-agent reinforcement learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 9394-9402, 2020.", + "[29] Shiqi Lin, Tao Yu, Ruoyu Feng, Xin Li, Xin Jin, and Zhibo Chen. Local patch autoaugment with multi-agent collaboration. arXiv preprint arXiv:2103.11099, 2021.", + "[30] Michael L Littman et al. Friend-or-foe q-learning in general-sum games. In ICML, volume 1, pages 322–328, 2001.", + "[31] Ze Liu, Jia Ning, Yue Cao, Yixuan Wei, Zheng Zhang, Stephen Lin, and Han Hu. Video swim transformer. arXiv preprint arXiv:2106.13230, 2021.", + "[32] Chaofan Ma, Qisen Xu, Xiangfeng Wang, Bo Jin, Xiaoyun Zhang, Yanfeng Wang, and Ya Zhang. Boundary-aware supervoxel-level iteratively refined interactive 3d image segmentation with multi-agent reinforcement learning. IEEE Transactions on Medical Imaging, 40(10):2563-2574, 2020." + ], + "bbox": [ + 503, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "13513", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[33] Naima Otberdout, Mohammed Daoudi, Anis Kacem, Lahoucine Ballihi, and Stefano Berretti. Dynamic facial expression generation on hilbert hypersphere with conditional Wasserstein generative adversarial nets. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020.", + "[34] Dipika Singhania, Rahul Rahaman, and Angela Yao. Coarse to fine multi-resolution temporal convolutional network. In CVPR, 2021.", + "[35] Li Siyao, Weijiang Yu, Tianpei Gu, Chunze Lin, Quan Wang, Chen Qian, Chen Change Loy, and Ziwei Liu. Bailando: 3d dance generation by actor-critic gpt with choreographic memory. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11050-11059, 2022.", + "[36] Sebastian Stein and Stephen J McKenna. Combining embedded accelerometers with computer vision for recognizing food preparation activities. In Proceedings of the 2013 ACM international joint conference on Pervasive and ubiquitous computing, pages 729-738, 2013.", + "[37] Richard S Sutton and Andrew G Barto. Reinforcement learning: An introduction. MIT press, 2018.", + "[38] Liangliang Wang, Lianzheng Ge, Ruifeng Li, and Yajun Fang. Three-stream cnns for action recognition. Pattern Recognition Letters, 92:33-40, 2017.", + "[39] Yuqing Wang, Zhaoliang Xu, Xinlong Wang, Chunhua Shen, Baoshan Cheng, Hao Shen, and Huaxia Xia. End-to-end video instance segmentation with transformers. In CVPR, 2021.", + "[40] Zhenzhi Wang, Ziteng Gao, Limin Wang, Zhifeng Li, and Gangshan Wu. Boundary-aware cascade networks for temporal action segmentation. In ECCV, 2020.", + "[41] Dongxu Wei, Xiaowei Xu, Haibin Shen, and Kejie Huang. Gac-gan: A general method for appearance-controllable human video motion transfer. IEEE Transactions on Multimedia, 23:2457-2470, 2020.", + "[42] Di Wu, Junjun Chen, Nabin Sharma, Shirui Pan, Guodong Long, and Michael Blumenstein. Adversarial action data augmentation for similar gesture action recognition. In 2019 International Joint Conference on Neural Networks (IJCNN), pages 1-8. IEEE, 2019.", + "[43] Fangqiu Yi, Hongyu Wen, and Tingting Jiang. AS-Former: Transformer for action segmentation. CoRR, arXiv 2110.08568, 2021." + ], + "bbox": [ + 78, + 90, + 470, + 698 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "13514", + "bbox": [ + 480, + 945, + 519, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/Markov Game Video Augmentation for Action Segmentation/3ebb7b09-a6e7-4446-89ff-eb9741fd0b7f_model.json b/2023/Markov Game Video Augmentation for Action Segmentation/3ebb7b09-a6e7-4446-89ff-eb9741fd0b7f_model.json new file mode 100644 index 0000000000000000000000000000000000000000..805059a8f4dc0304ced6bc98fb2491a370b03f57 --- /dev/null +++ b/2023/Markov Game Video Augmentation for Action Segmentation/3ebb7b09-a6e7-4446-89ff-eb9741fd0b7f_model.json @@ -0,0 +1,1980 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.807, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.18, + 0.131, + 0.792, + 0.153 + ], + "angle": 0, + "content": "Markov Game Video Augmentation for Action Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.293, + 0.183, + 0.416, + 0.198 + ], + "angle": 0, + "content": "Nicolas Aziere" + }, + { + "type": "text", + "bbox": [ + 0.258, + 0.2, + 0.451, + 0.218 + ], + "angle": 0, + "content": "Oregon State University" + }, + { + "type": "text", + "bbox": [ + 0.253, + 0.22, + 0.458, + 0.233 + ], + "angle": 0, + "content": "azieren@oregonstate.edu" + }, + { + "type": "text", + "bbox": [ + 0.552, + 0.182, + 0.688, + 0.198 + ], + "angle": 0, + "content": "Sinisa Todorovic" + }, + { + "type": "text", + "bbox": [ + 0.523, + 0.2, + 0.715, + 0.218 + ], + "angle": 0, + "content": "Oregon State University" + }, + { + "type": "text", + "bbox": [ + 0.522, + 0.22, + 0.719, + 0.234 + ], + "angle": 0, + "content": "sinisa@oregonstate.edu" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.269, + 0.314, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.302, + 0.473, + 0.633 + ], + "angle": 0, + "content": "This paper addresses data augmentation for action segmentation. Our key novelty is that we augment the original training videos in the deep feature space, not in the visual spatiotemporal domain as done by previous work. For augmentation, we modify original deep features of video frames such that the resulting embeddings fall closer to the class decision boundaries. Also, we edit action sequences of the original training videos (a.k.a. transcripts) by inserting, deleting, and replacing actions such that the resulting transcripts are close in edit distance to the ground-truth ones. For our data augmentation we resort to reinforcement learning, instead of more common supervised learning, since we do not have access to reliable oracles which would provide supervision about the optimal data modifications in the deep feature space. For modifying frame embeddings, we use a meta-model formulated as a Markov Game with multiple self-interested agents. Also, new transcripts are generated using a fast, parameter-free Monte Carlo tree search. Our experiments show that the proposed data augmentation of the Breakfast, GTEA, and 50Salads datasets leads to significant performance gains of several state of the art action segmenters." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.664, + 0.21, + 0.68 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.689, + 0.47, + 0.886 + ], + "angle": 0, + "content": "This paper presents a new data augmentation framework for fully supervised action segmentation of untrimmed videos. Action segmentation is a basic vision problem. Despite recent tremendous advances in terms of new action segmenters and learning strategies, there is relatively slow progress in increasing the size of existing benchmark datasets. In comparison with peer datasets for action recognition or image classification, available benchmarks for action segmentation are significantly smaller. This presents challenges in training of recent action segmenters which show tendency to overfit on small datasets [11, 43, 40]. However, compiling large datasets is difficult, due to, in part, high costs of manual annotation of action segments." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.887, + 0.469, + 0.902 + ], + "angle": 0, + "content": "We propose to augment existing datasets with newly gen" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.27, + 0.892, + 0.362 + ], + "angle": 0, + "content": "erated video sequences, such that the resulting data augmentation enables more robust training and hence improves performance of action segmenters. Our approach is agnostic of a particular model for action segmentation, and expects that the segmenter has been pre-trained on the original training dataset to predict action classes of video frames." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.365, + 0.893, + 0.517 + ], + "angle": 0, + "content": "Augmentation of video data has been mostly considered in the spatiotemporal, visual domain [38, 25, 19], where a human expert would heuristically specify the amount and type of data manipulation (e.g., subsampling, cropping, flipping of video frames) that are useful in training. While these approaches show great success, it is hard to formalize them in a principled manner. Others learn to generate new videos [9, 8, 42, 41], but the results are not sufficiently realistic yet, and hence would require domain adaptation if used for data augmentation in action segmentation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.52, + 0.895, + 0.822 + ], + "angle": 0, + "content": "Our key novelty is that we augment the original training videos directly in the deep feature space, unlike most previous work. As shown in Fig. 1 (top left), for augmentation, we modify original deep features of video frames at the input, such that the resulting embeddings fall closer to the class decision boundaries. Thus, by construction, we enforce that the augmented features be more challenging for learning, and in this way subsequently enable more robust training of the action segmenter. In addition, Fig. 1 (top right) illustrates that we also edit action sequences of the original training videos (a.k.a. transcripts) by inserting, deleting, and replacing actions, such that the resulting transcripts are close in edit distance to the groundtruth ones. Since the generated transcripts are kept similar to the originals, they are expected to be meaningful (i.e., legal) and provide a greater variety of legal action sequences than seen in the original training set. This is especially important for those application domains where some transcripts of interest are naturally rare and hence underrepresented in the original training dataset." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.895, + 0.903 + ], + "angle": 0, + "content": "For the proposed augmentation of frame embeddings in the deep feature space, we specify a deep residual metamodel, as shown in Fig. 1 (bottom left). The meta-model takes deep features of frames at the input and predicts an optimal amount of feature modifications - i.e., offset fea" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.958 + ], + "angle": 0, + "content": "13505" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.091, + 0.468, + 0.252 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.269, + 0.47, + 0.435 + ], + "angle": 0, + "content": "Figure 1. The proposed two-pronged data augmentation: (top and bottom left) Original deep features of frames at the input of a meta-model are modified to fall closer to class decision boundaries of the pretrained action segmenter. Alternative frameworks are considered for training the meta-model, including Gaussian noise, or supervised learning of a Temporal CNN, or reinforcement learning of an Actor-Critic network. (top and bottom right) The original action transcripts of training videos are modified by inserting, replacing, and removing actions, while ensuring a small edit distance between the newly generated transcripts and the originals. For training the meta-model for transcript augmentation, we consider supervised learning and alternatively a Monte Carlo tree search." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.447, + 0.468, + 0.522 + ], + "angle": 0, + "content": "tures which are added to the original frame features, resulting in augmented embeddings. For training the meta-model, we consider both RL (Fig. 1 (bottom left)) and supervised learning. From our experiments, RL proves to be a more reliable paradigm." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.523, + 0.468, + 0.704 + ], + "angle": 0, + "content": "Supervised learning of the proposed meta-model faces a fundamental challenge. As a direct consequence of performing data augmentation in the deep feature space, there is no reliable oracle which would provide supervision for the optimal amount of feature modifications. The only available oracle is the pre-trained action segmentation model which could predict action labels of the augmented frame embeddings, and the incurred loss could be used for training the meta-model. The action segmentation model provides only pseudo-labels for generated data – not ground-truth labels – and hence a fully-supervised training of our meta-model could suffer from noisy pseudo-labels." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.705, + 0.468, + 0.901 + ], + "angle": 0, + "content": "An alternative is to resort to reinforcement learning (RL) due to the following advantages. First, it allows us to sequentially modify frame features, where previous modifications define a state in which RL estimates an optimal modification of the next frames. Learning of the proposed sequential feature augmentation is expected to be more reliable, especially for long video sequences, than learning how to optimally modify all frame embeddings at once. RL produces an optimal policy which would account for temporal dependence between frame embeddings, and hence make them suitable for action segmentation models with large temporal receptive fields (like MS-TCN or AS-Former). Second, RL is expected to provide for a more sta" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.272 + ], + "angle": 0, + "content": "ble training of our meta-model by optimizing the expected reward over a policy of feature modifications, in comparison with the aforementioned minimization of the unreliable loss of the pretrained action segmenter on particular feature modifications. Third, RL is known to be very effective for problems with a large, continuous, output space, as is our case of predicting offset features in the deep feature space. Finally, RL is known to successfully address non-stationary environments with the distribution shift between training and test sets [37], which exactly characterizes our problem statement where data augmentation is aimed at bridging the distribution shift." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.273, + 0.892, + 0.378 + ], + "angle": 0, + "content": "Within the RL framework, for modifying frame embeddings, we formulate the meta-model as a Deep Actor-Critic Network for learning policies of two self-interested agents in a Markov Game. Also, for generating new transcripts, we use a fast, parameter-free Monte Carlo tree search. We call our approach Markov Game Video Augmentation (MVGA)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.379, + 0.892, + 0.484 + ], + "angle": 0, + "content": "Our experimental evaluation shows significant performance gains of recent convolutional and transformer-based action segmenters when our MVGA is used to augment the Breakfast, GTEA, and 50Salads datasets. Interestingly, MVGA enables the convolutional model MS-TCN [11, 27] achieve close performance to that of the significantly more complex (and more recent) ASFormer [43]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.484, + 0.892, + 0.545 + ], + "angle": 0, + "content": "In the following, Sec. 2 reviews closely related work, Sec. 3 gives an overview of MVGA, Sec. 4 specifies our transcript augmentation, Sec. 5 formalizes our frame-feature augmentation, and Sec. 6 presents our results." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.559, + 0.642, + 0.574 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.584, + 0.89, + 0.614 + ], + "angle": 0, + "content": "This section reviews closely related work on fully supervised action segmentation and video data augmentation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.614, + 0.892, + 0.825 + ], + "angle": 0, + "content": "A family of temporal convolution models [10, 23, 24, 11, 40, 27, 34] have been studied for action segmentation. Some of these models use gradual temporal pooling for overcoming oversegmentation [10, 23, 24, 34], and others integrate reasoning about action boundaries [40, 18]. As representatives of this family, in our experiments, we consider MS-TCN [11, 27] and boundary-aware BCN [40] both of which consist of multiple stages of temporal convolution layers. Recent transformer-based models [43, 31, 39, 2] outperform temporal convolution models. Among these transformers, for evaluation, we consider ASFormer [43]. Both MS-TCN and ASFormer use standard I3D deep features [5]) of video frames as input. We also study a version of ASFormer with more informative frame embeddings [26]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Video augmentation in the visible space-time domain, such as, e.g., temporal cropping of frames [38, 25] or random cropping/removing/flipping of frames in a training mini-batch [19] have become standard practice in action recognition, person re-ID, and hand gesture recogni" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "13506" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.468, + 0.198 + ], + "angle": 0, + "content": "tion. Other data augmentation methods have also been used, including pooling frame features within a window of variable length [34]. For video augmentation, some approaches generate simulated videos with video-game engines [9, 8], or GANs [14, 42, 41, 33]. However, there is still a large domain gap between such simulated and real videos, which limits the utility of these methods for data augmentation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.198, + 0.468, + 0.288 + ], + "angle": 0, + "content": "Reinforcement learning has been used for addressing various vision problems, including 3D image segmentation [28, 32], image classification [29], object detection [3, 4], and tracking [6, 16]. To the best of our knowledge, video data augmentation for action segmentation has never been formulated within the reinforcement learning framework." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.304, + 0.269, + 0.319 + ], + "angle": 0, + "content": "3. Overview of MVGA" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.33, + 0.468, + 0.526 + ], + "angle": 0, + "content": "In this and following two sections, we focus on our reinforcement learning formulation of the proposed data augmentation. The supervised learning formulation is described in Sec. 6. Fig. 2 shows an overview of our approach which consists of the following four steps. The first step pre-trains an action segmenter on a given training dataset \\(\\mathcal{D}\\). A training video of length \\(T\\) in \\(\\mathcal{D}\\) is given by its deep features for every frame \\(\\mathcal{X} = \\{x_t : t = 1, \\dots, T\\}\\), where \\(x_t \\in \\mathbb{R}^{d_{\\mathrm{in}}}\\) (\\(d_{\\mathrm{in}} = 2048\\) for standard I3D features [5]), and the ground-truth action classes \\(\\mathcal{Y} = \\{y_t : t = 1, \\dots, T\\}\\), where \\(y_t \\in \\mathbb{Y}\\) and \\(\\mathbb{Y}\\) is a set of action classes. After pretraining, the action segmenter \\(f_{\\theta}\\) can be used to predict action classes of video frames \\(\\hat{\\mathcal{Y}} = f(\\mathcal{X}; \\theta)\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.527, + 0.468, + 0.646 + ], + "angle": 0, + "content": "The second step generates new transcripts and their corresponding videos. We use the UCT algorithm [20] to first efficiently construct a tree, whose paths from the root to leaves represent legal transcripts, and then select optimal paths. For every new transcript, a new video is constructed by copying appropriate action segments from real videos in \\(\\mathcal{D}\\) to the new video following the action sequence of the new transcript." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.648, + 0.468, + 0.738 + ], + "angle": 0, + "content": "The third step augments features of the original and new videos with the Actor and Critic networks, which gives the augmented dataset \\(\\mathcal{D}'\\). The Actor predicts how much and where to modify features in the input video. The Critic estimates the expected rewards for the Actor. Both Actor and Critic are learned using the pre-trained \\(f_{\\theta}\\) as oracle." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.739, + 0.468, + 0.768 + ], + "angle": 0, + "content": "The fourth step fine-tunes \\( f_{\\theta} \\) such that every mini-batch consists of videos from both \\( \\mathcal{D} \\) and \\( \\mathcal{D}' \\)." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.77, + 0.462, + 0.785 + ], + "angle": 0, + "content": "In the following, we specify the second and third steps." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.8, + 0.422, + 0.816 + ], + "angle": 0, + "content": "4. New Transcript and Video Generation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.826, + 0.468, + 0.901 + ], + "angle": 0, + "content": "From \\(\\mathcal{D}\\), we generate new transcripts and their corresponding new videos. The new transcripts should be semantically meaningful, i.e., legal. This is enforced by requiring that the new transcripts have: (i) similar lengths as the original transcripts; and (ii) high likelihoods of consec" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.243 + ], + "angle": 0, + "content": "utive pairs of action classes. Our experiments suggest that auto-regressive models - e.g., a recurrent-neural network (RNN) or Transformer network [35] - provide poor transcript generation, since they require large training datasets and hence have limited utility for our target settings where data augmentation is needed to address lack of data. Therefore, in this section, we focus on an alternative framework - parameter-free Monte-Carlo Tree Search (MTCS), where the space of transcripts is efficiently represented by a tree. We first construct the tree, and then identify its optimal path." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.253, + 0.831, + 0.269 + ], + "angle": 0, + "content": "4.1. MTCS for New Transcript Generation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.277, + 0.892, + 0.398 + ], + "angle": 0, + "content": "In the tree of transcripts, the root represents the dummy \"start\" of action sequences. The root's descendants sequentially add action classes to the transcripts until leaf nodes, which represent the dummy \"end\". A node \\( v \\) represents the last action class of the path \\( \\pi_v \\) from the root to \\( v \\), \\( \\pi_v = \\{\\text{\"start\", } y_1, \\dots, y_v}\\} \\), where \\( y_v \\in \\mathbb{Y} \\) or \\( y_v = \\text{\"end\"} \\) if \\( v \\) is a leaf node. Each node is assigned a weight, \\( w(v) \\), specified as the joint likelihood of the corresponding path:" + }, + { + "type": "equation", + "bbox": [ + 0.577, + 0.41, + 0.891, + 0.445 + ], + "angle": 0, + "content": "\\[\nw (v) = p \\left(\\left| \\pi_ {v} \\right|\\right) \\prod_ {\\left(u, u ^ {\\prime}\\right) \\in \\pi_ {v}} p \\left(y _ {u ^ {\\prime}} \\mid y _ {u}\\right), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.456, + 0.892, + 0.576 + ], + "angle": 0, + "content": "where \\( p(|\\pi_v|) \\) is a prior of the transcript length, \\( u' \\) is a child of \\( u \\) along \\( \\pi_v \\), and \\( p(y_{u'} | y_u) \\) denotes the transition probability of consecutive actions. In the special case, \\( p(y_{u'} | \"start\") \\) and \\( p(\"end\" | y_u) \\) represent the priors that the transcript begins and ends with classes \\( y_{u'}, y_u \\in \\mathbb{Y} \\). Both \\( p(|\\pi_v|) \\) and \\( p(y_{u'} | y_u) \\) are estimated from \\( \\mathcal{D} \\). For \\( p(|\\pi_v|) \\) we learn the Poisson distribution, and for \\( p(y_{u'} | y_u) \\) we estimate the frequency of the corresponding class transitions in \\( \\mathcal{D} \\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.578, + 0.892, + 0.73 + ], + "angle": 0, + "content": "The tree is constructed iteratively using the well-known UCT algorithm [20] which balances a trade-off between exploitation and exploration. In each iteration, the root is sequentially expanded with a path of optimal descendants until the dummy \"end\" leaf or the maximum tree depth is reached. We do not allow illegal expansions, i.e., a path is guaranteed to consist of class transitions seen in \\(\\mathcal{D}\\). Suppose a path has reached node \\(u\\) without meeting the stopping criterion. Then, UCT adds to the path the optimal node \\(u'\\) from a subset of children, \\(\\mathrm{ch}(u) \\subset \\mathrm{Ch}(u) = \\{u': p(y_{u'} | y_u) > 0\\}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.558, + 0.741, + 0.892, + 0.782 + ], + "angle": 0, + "content": "\\[\nu ^ {\\prime} = \\arg \\max _ {v \\in \\operatorname {c h} (u)} \\left[ w (v) + c \\sqrt {\\frac {2 \\log n (u)}{n (v)}} \\right] \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.792, + 0.892, + 0.901 + ], + "angle": 0, + "content": "where \\(\\operatorname{ch}(u)\\) is randomly sampled \\(50\\%\\) of \\(\\operatorname{Ch}(u)\\) to enable exploring alternative paths; \\(w(v)\\) is given by (1); \\(c = \\frac{1}{\\sqrt{2}}\\) is the exploration-exploitation trade-off parameter; and \\(n(v)\\) is the number of paths in the current tree that include node \\(v\\). As the tree iteratively grows, the value of \\(n(v)\\) keeps changing for every node, which enables exploring less visited nodes in the space of transcripts even if \\(w(v)\\) is small." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13507" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.164, + 0.089, + 0.812, + 0.339 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.345, + 0.895, + 0.43 + ], + "angle": 0, + "content": "Figure 2. Our MVGA consists of four steps. 1-An action segmentation model is pre-trained using the original training set. 2-New transcripts are generated by selecting optimal paths in a UCT tree [20] of legal transcripts. For every new transcript, a new video is constructed by copying instances of action classes in the new transcript from real videos. 3- Features of the original and constructed new videos are augmented with the Actor and Critic networks. The Actor predicts the amount and location of feature modifications in the video. The Critic estimates the expected rewards for the Actor's two predictions. Both Actor and Critic are learned using the pre-trained action segmenter as oracle. 4- The action segmenter is fine-tuned on the original and augmented training videos." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.453, + 0.471, + 0.514 + ], + "angle": 0, + "content": "After 1000 tree-growing iterations, the node \\( v^{*} \\) with the highest likelihood \\( v^{*} = \\arg \\max_{v} w(v) \\) in the tree uniquely identifies the newly generated transcript \\( \\pi_{v^{*}} \\). For generating another transcript, we construct another tree anew." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.522, + 0.446, + 0.539 + ], + "angle": 0, + "content": "4.2. Generating New Videos of New Transcripts" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.546, + 0.471, + 0.804 + ], + "angle": 0, + "content": "Given a new transcript, \\(\\pi\\), we sequentially construct a new video with deep features (e.g., I3D [5]) following the ordering of action classes in \\(\\pi\\). It is worth emphasizing that our video generation occurs directly in the deep feature space. We begin by selecting a video \\(\\mathcal{X}_0 \\in \\mathcal{D}\\) whose ground-truth transcript has the smallest edit distance to \\(\\pi\\). From \\(\\mathcal{X}_0\\), we remove all action segments that are not represented in \\(\\pi\\), resulting in our initial new video \\(\\mathcal{X}_0'\\). For action classes that are present in \\(\\pi\\) but missing in \\(\\mathcal{X}_0'\\), we identify the second closest video \\(\\mathcal{X}_1 \\in \\mathcal{D}\\) with these missing actions, and copy their respective temporal intervals to the appropriate locations in the new video, resulting in \\(\\mathcal{X}_1'\\). This is repeated until the entire \\(\\pi\\) is fully represented by \\(\\mathcal{X}_g'\\), \\(g = 0, 1, 2, \\ldots\\). Note that \\(\\mathcal{X}_g'\\) keeps the original lengths of action instances found in real videos, which ensures temporal coherence of every action in \\(\\mathcal{X}_g'\\). A pseudo-code of the proposed video generation is given in the supplement." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.816, + 0.381, + 0.833 + ], + "angle": 0, + "content": "5. Augmentation of Frame Features" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Features of both original and new videos are augmented by a Markov Game (MG) [15, 30, 37]. Since MG is a well-studied framework and we do not claim novelty in our particular formulation, below we rely that the reader is al-" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.453, + 0.895, + 0.775 + ], + "angle": 0, + "content": "ready familiar with the motivation and main concepts of MG. Our MG consists of two agents which sequentially take independent actions causing state changes of a fully observable environment. The environment at step \\(k\\) is defined by state \\(s_k = (\\mathcal{X}_k, \\mathcal{M}_k)\\), where \\(\\mathcal{X}_k = \\{x_{k,t} : t = 1, \\dots, T\\}\\) is the set of current video frame features, and \\(\\mathcal{M}_k = \\{m_{k,t} : t = 1, \\dots, T\\}\\) is a binary mask assigned to the video frames, \\(m_{k,t} \\in \\{0,1\\}\\), for keeping the record which frames have been already modified. Given \\(s_k\\), the two agents follow their respective policies, \\(\\mu^1\\) and \\(\\mu^2\\), to take actions \\(a_k^1 = \\mu^1(s_k) \\in \\mathcal{A}^1\\) and \\(a_k^2 = \\mu^2(s_k) \\in \\mathcal{A}^2\\). \\(\\mathcal{A}^1\\) is a continuous action space of agent 1, where \\(a_k^1 = \\{a_{t,k}^1 : t = 1, \\dots, T\\}\\) represents the amount of feature augmentation, i.e., offset features. \\(\\mathcal{A}^2\\) is a discrete action space of agent 2 for selecting video frames for augmentation, \\(a_k^2 \\in \\{0,1\\}^T\\), where \\(a_{t,k}^2 = 0\\) means that the frame \\(t\\) will not be augmented in step \\(k\\). \\(a_k^1\\) and \\(a_k^2\\) cause the environment to change to next state \\(s_{k+1}\\), which incurs the respective two rewards \\(R_k^1 = R^1(s_k, s_{k+1}, f_\\theta)\\) and \\(R_k^2 = R^2(s_k, a_2^k)\\). Our goal is to learn \\(\\mu^1\\) and \\(\\mu^2\\) so as to maximize the agents' action-value functions given by:" + }, + { + "type": "equation", + "bbox": [ + 0.515, + 0.789, + 0.892, + 0.837 + ], + "angle": 0, + "content": "\\[\nQ ^ {i} (s, a) = \\mathbb {E} \\left[ \\sum_ {k \\geq 0} (\\gamma) ^ {k} R _ {k} ^ {i} \\mid \\mu^ {i}, a _ {0} ^ {i} = a, s _ {0} = s \\right], i = \\{1, 2 \\} \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.838, + 0.892, + 0.868 + ], + "angle": 0, + "content": "where \\(\\mathbb{E}[\\cdot ]\\) denotes expected value, \\(\\gamma = 0.99\\) is the discount factor raised to the power of \\(k\\), \\(s\\in S\\), and \\(a\\in \\mathcal{A}^i\\)." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.894, + 0.902 + ], + "angle": 0, + "content": "For a given video, MG starts from the initial state \\( s_0 = (\\mathcal{X}_0, \\mathcal{M}_0) \\), with the original frame features and all-zero" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13508" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.091, + 0.47, + 0.123 + ], + "angle": 0, + "content": "mask, \\(\\mathcal{X}_0 = \\mathcal{X}\\) and \\(\\mathcal{M}_0 = \\{0\\}^T\\). In state \\(s_k\\), the two agents take their respective actions, which gives \\(s_{k + 1}\\) specified as" + }, + { + "type": "equation", + "bbox": [ + 0.11, + 0.132, + 0.468, + 0.15 + ], + "angle": 0, + "content": "\\[\n\\mathcal {X} _ {k + 1} = \\left\\{x _ {t, k} + a _ {t, k} ^ {2} \\left(a _ {t, k} ^ {1} + \\epsilon\\right): t = 1, \\dots , T \\right\\}, \\tag {4}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.102, + 0.153, + 0.469, + 0.171 + ], + "angle": 0, + "content": "\\[\n\\mathcal {M} _ {k + 1} = \\mathcal {M} _ {k} \\vee a _ {k} ^ {2}, \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.18, + 0.47, + 0.302 + ], + "angle": 0, + "content": "where \\(\\vee\\) is the logical OR operator, and \\(\\epsilon \\in \\mathbb{R}^{d_{\\mathrm{in}}}\\) is noise sampled from the zero-mean and unit-variance Gaussian distribution. \\(\\epsilon\\) enables an exploration of \\(\\mathcal{A}^1\\) and provides a way to generate multiple, distinct, augmented features from the same initial state \\(s_0\\). From (4), only frames selected by \\(a_k^2\\) get updated with the corresponding offset features \\((a_k^1 + \\epsilon)\\). Also, from (5), mask \\(\\mathcal{M}_k\\) keeps the record of previously selected frames for augmentation." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.302, + 0.469, + 0.349 + ], + "angle": 0, + "content": "MG stops as soon as one of the following happens (experimentally optimized): after \\( k = 10 \\) steps, or when \\( 95\\% \\) of the video has been augmented, \\( \\sum_{t=1}^{T} m_{t,k} \\geq 0.95T \\)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.356, + 0.422, + 0.372 + ], + "angle": 0, + "content": "5.1. Two Rewards for Feature Augmentation" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.379, + 0.47, + 0.668 + ], + "angle": 0, + "content": "The policy of agent 1, \\(\\mu^1\\), is learned to augment original features, such that they become more challenging for the pre-trained action segmenter, \\(f_{\\theta}\\), and thus provide for a more robust subsequent training of \\(f_{\\theta}\\) on the augmented training dataset. This is enforced by specifying the following reward \\(R_k^1 = R^1(s_k, s_{k+1}, f_{\\theta})\\). Let \\(\\hat{y}_t\\) and \\(\\hat{y}_t'\\) denote the top two scoring class predictions for \\(x_{t,k}\\) by \\(f_{\\theta}\\), \\(\\hat{y}_t = \\arg \\max_{y \\in \\mathbb{Y}} p(y|x_{t,k};\\theta)\\) and \\(\\hat{y}_t' = \\arg \\max_{y \\in \\mathbb{Y} \\setminus \\{\\hat{y}_t\\}} p(y|x_{t,k};\\theta)\\). We penalize agent 1 with a negative reward whenever \\(a_k^1\\) causes \\(f_{\\theta}\\) to make a wrong prediction, \\(\\hat{y}_t \\neq y_t\\). We assign a positive reward to agent 1 when \\(f_{\\theta}\\)'s prediction is equal to the ground truth, \\(\\hat{y}_t = y_t\\), and reduce this positive reward if the feature augmentation is not challenging enough for \\(f_{\\theta}\\). The positive reward reduction is proportional to \\(f_{\\theta}\\)'s confidence in its prediction, specified as a difference between its top two scoring predictions, \\(\\kappa = [p(\\hat{y}_t|x_{t,k};\\theta) - p(\\hat{y}_t'|x_{j,k};\\theta)]\\), \\(0 < \\kappa \\leq 1\\). Hence, when confidence \\(\\kappa\\) is large and close to 1, the positive reward for agent 1 is maximally reduced as" + }, + { + "type": "equation", + "bbox": [ + 0.137, + 0.681, + 0.369, + 0.72 + ], + "angle": 0, + "content": "\\[\nR _ {k} ^ {1} = \\frac {1}{\\| a _ {k} ^ {2} \\|} \\sum_ {t \\in \\mathcal {T} (a _ {k} ^ {2})} r ^ {1} (x _ {t, k + 1}, f _ {\\theta}),\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.08, + 0.72, + 0.472, + 0.793 + ], + "angle": 0, + "content": "\\[\nr ^ {1} \\left(x _ {t, k}, f _ {\\theta}\\right) = \\left\\{ \\begin{array}{l l} 1 - \\left[ p \\left(\\hat {y} _ {t} \\mid x _ {t, k}; \\theta\\right) - p \\left(\\hat {y} _ {t} ^ {\\prime} \\mid x _ {t, k}; \\theta\\right) \\right], & \\text {i f} \\hat {y} _ {t} = y _ {t} \\\\ - 1 & , \\text {i f} \\hat {y} _ {t} \\neq y _ {t} \\end{array} \\right. \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.793, + 0.428, + 0.81 + ], + "angle": 0, + "content": "where \\(\\mathcal{T}(a_k^2)\\) returns the set of frames where \\(a_{t,k}^2 = 1\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.469, + 0.902 + ], + "angle": 0, + "content": "For the policy of agent 2, \\(\\mu^2\\), we specify the following three requirements: (i) \\(\\mu^2\\) should not select frames which have already been augmented in the previous MG steps; (ii) frame selection should be local at each MG step and focus only on a very few action instances in the video (and in this way make learning of \\(\\mu^1\\) easier); and (iii) selected temporal" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.138 + ], + "angle": 0, + "content": "intervals should maximally overlap the ground-truth action instances. These three requirements are enforced by specifying the following reward:" + }, + { + "type": "equation", + "bbox": [ + 0.506, + 0.148, + 0.892, + 0.23 + ], + "angle": 0, + "content": "\\[\nR _ {k} ^ {2} = \\left\\{ \\begin{array}{c} \\sum_ {\\tau} \\frac {| \\tau \\cap a _ {k} ^ {2} |}{| \\tau |}, \\text {i f} \\sum_ {t} a _ {t, k} ^ {2} m _ {t, k} < \\alpha \\text {a n d} \\| a _ {k} ^ {2} \\| < \\frac {T}{2} \\\\ - 1, \\text {o t h e r w i s e} \\end{array} \\right. \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.231, + 0.892, + 0.337 + ], + "angle": 0, + "content": "\\(\\tau\\) is the ground-truth mask of actions over frames, and enforces that each iteration of the video augmentation covers the entire time interval of an action rather than randomly scattered frames. \\(\\alpha = 0.4T\\) is an experimentally optimized threshold which allows a flexible frame selection of up to \\(40\\%\\) of the past \\(\\mathcal{M}_k\\). From (7), agent 2 is penalized when selects more than a half of the video for augmentation." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.346, + 0.892, + 0.363 + ], + "angle": 0, + "content": "5.2. Learning the Policies for Feature Augmentation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.369, + 0.892, + 0.55 + ], + "angle": 0, + "content": "To learn \\(\\mu^1\\) and \\(\\mu^2\\), we design an Actor-Critic model with a decentralized-actor deep network for computing the agents' actions, and a centralized-critic deep network for efficiently estimating action-value functions \\(\\hat{Q}^1\\) and \\(\\hat{Q}^2\\), as shown in Fig. 3. The Actor-Critic framework has been demonstrated effective for continuous agent-action spaces and when the agents have individual rewards [17], as in our case. In general, decentralizing the actor network helps increase stationarity of environments with self-interested agents [37]. The centralized critic network is suitable because it allows relevant information from all of the agents to be shared toward estimating each agent's expected reward." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.551, + 0.892, + 0.642 + ], + "angle": 0, + "content": "As can be seen in Fig. 3, the input to the actor network, \\( s_k = (\\mathcal{X}_k, \\mathcal{M}_k) \\), is passed through a backbone, specified as a multi-stage temporal convolutional neural network (TCN) [11], in order to estimate the latent (deep) representation of \\( s_k \\). Then, two distinct 1-stage TCNs take this latent representation as input and compute the frame selection" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.664, + 0.892, + 0.829 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.842, + 0.892, + 0.899 + ], + "angle": 0, + "content": "Figure 3. Actor-Critic model for learning policies \\(\\mu^1\\) and \\(\\mu^2\\) consists of several stages of temporal convolution network (TCN). The actor network predicts feature augmentation, and the centralized critic estimates the expected rewards for each policy." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13509" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.091, + 0.468, + 0.17 + ], + "angle": 0, + "content": "\\(a_2^k\\) and feature offsets of the selected frames \\(a_k^1\\). Finally, the predicted \\(a_k^1\\), \\(a_2^k\\), and latent feature of \\(s_k\\) are passed to the centralized critic - specifically, a 2-stage TCN - to estimate the expected rewards \\(\\hat{Q}_k^1 = \\hat{Q}^1 (s_k,a_k^1,a_k^2)\\) and \\(\\hat{Q}_k^2 = \\hat{Q}^2 (s_k,a_k^1,a_k^2)\\) of \\(\\mu^1\\) and \\(\\mu^2\\)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.17, + 0.468, + 0.26 + ], + "angle": 0, + "content": "Parameters of the proposed actor-critic deep architecture are learned using the standard temporal difference learning [21]. The critic learns to iteratively simulate the action-value function, \\(\\hat{Q}_k^i\\), \\(i = \\{1, 2\\}\\), which is later used to update parameters of the actor network. To this end, we minimize the following loss of the critic network:" + }, + { + "type": "equation", + "bbox": [ + 0.144, + 0.272, + 0.468, + 0.311 + ], + "angle": 0, + "content": "\\[\nL _ {C} = \\sum_ {i \\in \\{1, 2 \\}} \\left(R _ {k} ^ {i} + \\gamma \\hat {Q} _ {k + 1} ^ {i} - \\hat {Q} _ {k} ^ {i}\\right) ^ {2}, \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.325, + 0.468, + 0.355 + ], + "angle": 0, + "content": "where \\(R_{k}^{i}\\) is given by (6) and (7), and \\(\\gamma\\) is the discount factor. The actor network is learned with the following loss:" + }, + { + "type": "equation", + "bbox": [ + 0.093, + 0.38, + 0.468, + 0.408 + ], + "angle": 0, + "content": "\\[\nL _ {A} ^ {i} = \\left\\| a _ {k} ^ {i} \\right\\| _ {2} ^ {2} \\cdot \\left(R _ {k} ^ {i} + \\gamma \\hat {Q} _ {k + 1} ^ {i} - \\hat {Q} _ {k} ^ {i}\\right) ^ {2}, i = \\{1, 2 \\}. \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.419, + 0.468, + 0.465 + ], + "angle": 0, + "content": "A proof in [37] shows that minimizing \\( L_{C} \\) and \\( L_{A} \\) in (8) and (9) optimizes \\( \\mu^{1} \\) and \\( \\mu^{2} \\) so they manage to achieve maximal rewards \\( R^{1} \\) and \\( R^{2} \\) given by (6) and (7), as desired." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.481, + 0.163, + 0.495 + ], + "angle": 0, + "content": "6. Results" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.507, + 0.468, + 0.657 + ], + "angle": 0, + "content": "Datasets include three benchmarks: Breakfast [22], GTEA [12], and 50Salads [36]. For each dataset, we precompute the standard I3D frame features without any self-supervision, fine-tuning, or data augmentation, as in [11]. Breakfast has 1712 videos with 48 action classes, GTEA shows 7 complex activities, each specified in terms of 11 action classes including the background class. 50Salads consists of 50 videos with 17 action classes. For Breakfast, GTEA, and 50Salads, we perform the standard 4-fold, 4-fold, and 5-fold cross validation, respectively." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.659, + 0.468, + 0.748 + ], + "angle": 0, + "content": "Metrics. Mean-of-Frame (MoF) is the average framework classification accuracy. Edit score counts edit operations to make the predicted and ground-truth sequences equivalent. F1 score counts true positives when a temporal intersection between the predicted and ground-truth segments is \\(10\\%\\), \\(25\\%\\) and \\(50\\%\\), denoted as F1@10,25,50." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Implementation details. The Actor-Critic has the same layers as MS-TCN [11]. One stage consists of 10 convolution layers with an increasing dilation rate and feature maps with size 128. The mask backbone and feature backbone each represents a 1-stage TCN. Their outputs are, first, concatenated, then, passed to a 4-stage MS-TCN, and, finally, input to the agents' heads. Agent 1's head is a 2-stage MS-TCN. Agent 2's head is a 1-stage TCN. The critic network is a 2-stage MS-TCN. The learning rate for the actor-critic training is 0.0001. Our training of the meta-model is run for" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.336 + ], + "angle": 0, + "content": "30 epochs. The NMS threshold is set to 0.5, and the minimum IOU is set to 0. The discount factor \\(\\gamma = 0.99\\). The policy training on Tesla-V100s for GTEA takes 3 hours. The MCTS algorithm runs 1000 node expansions in a couple of seconds. The maximum tree width is 200. The maximum tree depth is \\(\\hat{\\lambda} + 2\\sqrt{\\hat{\\lambda}}\\) where \\(\\hat{\\lambda}\\) is the average transcript length of the training set. The number of epochs in the fine-tuning on the original and augmented data is 50 epochs for MS-TCN, 100 epochs for ASFormer, and 50 epochs for BCN. The meta-training of the meta-model increases complexity compared to baseline approaches. It is important to separate the time for training an action segmentation model, and the time for our meta-training. Our meta-training can be viewed as a part of the dataset preparation, which takes significantly less time than manually collecting and annotating real videos." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.348, + 0.836, + 0.362 + ], + "angle": 0, + "content": "6.1. Ablation Studies of MS-TCN on GTEA" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.371, + 0.892, + 0.673 + ], + "angle": 0, + "content": "The training dataset size. Tab. 1 reports how MS-TCN performance on GTEA changes as a function of two variables: (i) the number of training transcripts; and (ii) the total number of original and augmented videos – both expressed as the increase factor of the original set. Tab. 1 shows that when the original set of training videos is tripled such that there are \\(20\\%\\) of new transcripts, MS-TCN achieves the best performance for all of the metrics, and this setting is used in the sequel. Too many augmentations using the same input video leads to similar data outputs, and consequently to overfitting in training of an action segmentation model. Note that testing the transcript augmentation as a standalone contribution is inappropriate and reduces performance (second row), since new transcripts need to be realized as new videos. These new videos are Frankenstein-like constructs from multiple real videos, and hence have highly unrealistic action transitions, and incoherent and sometimes impossible human motions. Therefore, the new videos require additional frame-feature augmentation to provide useful data augmentation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.675, + 0.892, + 0.87 + ], + "angle": 0, + "content": "Alternatives for generating transcripts. Tab. 2 compares two alternative methods for generating transcripts – namely, auto-regression and our UCT – in terms of: (i) edit distance to the ground-truth transcripts, and (ii) expected reward given by (1). The two metrics are averaged over the top \\(10\\%\\) and \\(20\\%\\) of generated transcripts that are the closest to the ground-truth transcripts. The auto-regressive model is a Transformer Network [35] trained with the cross-entropy loss to predict the next action class given an input sequence of action classes. From Tab. 2, our UCT generates transcripts which are more similar to the ground-truth ones than those produced by auto-regression. Also, the average likelihoods for UCT and ground truth are nearly the same." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "RL vs Non-RL for frame-feature augmentation. Tab. 3 compares the proposed reinforcement learning and" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13510" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.08, + 0.089, + 0.477, + 0.19 + ], + "angle": 0, + "content": "
#TranscriptsTrain. set sizeF1@10,25,50EditMoF
1×1×87.384.972.482.078.0
1.1×1×85.281.169.780.074.9
1×2×89.888.577.686.879.5
1.1×2×90.588.677.987.178.9
1.2×3×90.988.279.288.879.6
1.2×4×89.187.778.989.079.7
1.2×5×89.087.075.685.778.2
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.195, + 0.472, + 0.307 + ], + "angle": 0, + "content": "Table 1. MS-TCN performance on GTEA as a function of the number of training transcripts, and the number of original and augmented videos used for training -both expressed as the increase factor of the original training set. When our augmentation triples the set of training videos such that there are \\(20\\%\\) of newly generated transcripts, MS-TCN achieves the best performance. The top row is without any augmentation, and the second from the top row is for only feature augmentation without new transcripts." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.32, + 0.479, + 0.396 + ], + "angle": 0, + "content": "
MethodEdit dist. (%) Top 10%Edit dist. (%) Top 20%Likelihood Top 20%
Auto-regression19.522.00.59e-4
UCT14.015.21.41e-4
Ground truth--1.45e-4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.399, + 0.471, + 0.484 + ], + "angle": 0, + "content": "Table 2. Comparison of two alternative transcript generation methods – auto-regression by a Transformer Network [35], and our proposed UCT – in terms of an average edit distance between the generated and ground-truth transcripts for GTEA, and their average likelihood given by (1). The two metrics are averaged over the top \\(10\\%\\) and \\(20\\%\\) of generated transcripts closest to the ground-truth." + }, + { + "type": "table", + "bbox": [ + 0.081, + 0.496, + 0.462, + 0.585 + ], + "angle": 0, + "content": "
Frame AugmentationF1@10,25,50EditMoF
No augmentation [11]85.883.469.879.076.3
Noise85.783.271.979.677.5
Non-RL (Seq)83.180.969.176.276.5
Non-RL (All)83.981.570.477.677.7
Our RL-based90.988.279.288.879.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.585, + 0.468, + 0.64 + ], + "angle": 0, + "content": "Table 3. MS-TCN performance on GTAE, when using the best data augmentation setting given in Tab. 1, and for alternative strategies of frame-feature augmentation. Supervised learning in \"Non-RL\" decreases the performance of MS-TCN." + }, + { + "type": "table", + "bbox": [ + 0.124, + 0.654, + 0.421, + 0.711 + ], + "angle": 0, + "content": "
PoliciesF1@10,25,50EditMoF
μ1/1088.585.074.783.878.2
μ1/2087.484.874.184.577.8
μ1/μ290.988.279.288.879.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.711, + 0.468, + 0.739 + ], + "angle": 0, + "content": "Table 4. MS-TCN performance on GTAE for the proposed multiagent \\((\\mu_{1} / \\mu_{2})\\) and the alternative single-agent \\((\\mu_{1} / 10\\) or \\(\\mu_{1} / 20)\\)" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.47, + 0.901 + ], + "angle": 0, + "content": "an alternative supervised learning for frame-feature augmentation, when using the best data augmentation setting given in Tab. 1. We consider several baselines. \"Noise\" refers to simply adding Gaussian noise with zero mean and 0.01 variance to the original deep features of frames, as the original I3D features have an average value of 0.2 and variance 0.06. From Tab. 3, such a frame-feature augmentation with Gaussian noise barely has any effect on MS-TCN's performance. \"Non-RL\" is another baseline that uses su" + }, + { + "type": "table", + "bbox": [ + 0.511, + 0.089, + 0.88, + 0.133 + ], + "angle": 0, + "content": "
Class transition2, 52, 75, 98, 1010, 4
# Original dataset11233
# Augmented dataset22355
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.133, + 0.892, + 0.16 + ], + "angle": 0, + "content": "Table 5. Count of the least represented action transitions in the original and augmented training sets of GTEA." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.186, + 0.892, + 0.473 + ], + "angle": 0, + "content": "pervised learning for training the meta-model, as depicted in Fig. 1 (bottom left). In \"Non-RL\" the meta-model is a 1-stage TCN which outputs the offset feature for a given original feature at the input. As shown in Fig. 1 (bottom left), the resulting augmented feature is then passed to the pre-trained action segmenter. The meta-model is trained based on the cross-entropy loss of the pre-trained action segmenter, which serves as an oracle to ensure that the augmented feature remains in the action class of the original frame feature. For \"Non-RL\", we also regularize the resulting augmented feature to be different from the original feature with the standard contrastive loss. Moreover, we study two versions of \"Non-RL\" - one where all features of the entire video are modified at once, called \"Non-RL (All)\"; and the other with a sequential modification of frame features one action segment at a time, called \"Non-RL (Seq)\" From Tab. 3, both \"Non-RL (All)\" and \"Non-RL (Seq)\" decrease MS-TCN's performance. More details on \"Non-RL\" are presented in the supplement." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.473, + 0.892, + 0.625 + ], + "angle": 0, + "content": "Policy. Tab. 4 compares MS-TCN performance on GTAE for our multi-agent formulation and an alternative single-agent feature augmentation. The latter does not learn frame masking, and hence does not have our agent 2. The single-agent, denoted as \\(\\mu_1 / 10\\) or \\(\\mu_1 / 20\\), uses only policy \\(\\mu_1\\) for augmenting frame features. The values 10 and 20 indicate the percent of video randomly selected for augmentation at each policy iteration. Our multi-agent, denoted as \\(\\mu_1 / \\mu_2\\), uses both \\(\\mu_1\\) and \\(\\mu_2\\) policies. Tab. 4 shows that adding the second agent significantly improves the results." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.625, + 0.892, + 0.761 + ], + "angle": 0, + "content": "Improving transcripts variability. Generating new transcripts modify the total count of action transition initially present in the original set of transcripts. The advantage of our MCTS based generation approach is the emphasis on exploration. The number of poorly represented action transitions are increased with the new transcripts in training. Tab. 5 shows some example action transitions that are the least represented in the original training set get at least one new instance when adding the generated transcripts." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.772, + 0.746, + 0.788 + ], + "angle": 0, + "content": "6.2. Impact of MVGA on SOTA" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.892, + 0.901 + ], + "angle": 0, + "content": "The top of Tab. 6 reports results of state-of-the-art (SOTA) fully supervised methods that do not use video augmentation in training (some of them use sophisticated post-processing, which we do not have). Tab. 6 also shows how MVGA affects performance of SOTA approaches – including: MS-TCN[11], BCN [40], ASFormer [43], and BridgePrompt [26] – on Breakfast, GTAE, and 50Salads. As can" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "13511" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.089, + 0.89, + 0.299 + ], + "angle": 0, + "content": "
DatasetBreakfastGTEA50Salads
MethodF1@10,25,50EditMoFF1@10,25,50EditMoFF1@10,25,50EditMoF
MSTCN++ [27]64.158.645.965.667.687.886.274.482.678.980.778.570.174.383.7
ASRF [18]74.368.956.172.467.689.487.879.883.777.384.983.577.379.384.5
HASR [1]74.769.557.071.969.489.287.274.884.576.986.685.778.581.083.9
SSTDA [7]75.069.155.273.770.290.089.178.086.279.883.081.573.875.883.2
G2L [13]74.969.055.273.370.789.987.375.884.678.580.378.069.873.482.2
UVAST [2]76.770.056.668.286.277.169.754.290.562.281.270.483.977.169.7
MSTCN [11]52.648.137.961.766.385.883.469.879.076.376.374.064.567.980.7
MSTCN (Ours)58.154.644.463.466.887.384.972.482.078.075.873.866.868.282.7
MSTCN + MVGA68.966.155.868.171.190.988.879.288.279.680.177.971.274.183.2
BCN [40]68.765.555.066.270.488.587.177.384.479.882.381.374.074.384.4
BCN + MVGA70.867.757.368.371.891.390.080.686.780.583.782.475.877.285.6
ASFormer [43]76.070.657.475.073.590.188.879.284.679.785.183.476.079.685.6
ASFormer + MVGA75.672.159.776.874.291.390.579.386.480.386.384.978.781.386.0
Bridge-Prompt [26]94.192.083.091.681.289.287.881.383.888.1
Bridge-Prompt + MVGA95.293.484.892.182.690.889.483.286.188.9
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.08, + 0.301, + 0.891, + 0.327 + ], + "angle": 0, + "content": "Table 6. Impact of MVGA on SOTA methods on Breakfast, GTEA and 50Salads, and comparison with the other SOTA approaches that do not use data augmentation." + }, + { + "type": "table", + "bbox": [ + 0.089, + 0.339, + 0.882, + 0.439 + ], + "angle": 0, + "content": "
DatasetBreakfastGTEA50Salads
MethodF1@10,25,50EditMoFF1@10,25,50EditMoFF1@10,25,50EditMoF
MSTCN + C2F[34]58.255.047.862.966.586.283.578.178.876.577.374.265.567.380.8
MSTCN + Speed55.052.741.960.165.984.880.866.178.875.777.375.967.868.881.2
MSTCN + MVGA68.966.155.868.171.190.988.879.288.279.680.177.971.274.183.2
ASFormer + C2F [34]75.872.357.575.272.990.388.078.884.278.984.582.676.178.784.0
ASFormer + Speed75.269.156.974.871.989.387.277.785.278.584.482.975.177.285.1
ASFormer + MVGA75.672.159.776.874.291.390.579.386.480.386.384.978.781.386.0
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.201, + 0.44, + 0.768, + 0.451 + ], + "angle": 0, + "content": "Table 7. Comparison of different data augmentation methods on Breakfast, GTEA and 50Salads." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.476, + 0.47, + 0.718 + ], + "angle": 0, + "content": "be seen, for all of the four SOTA approaches, data augmentation by MVGA consistently produces performance gains relative to their respective performance without data augmentation. For instance, MSTCN+MVGA outperforms both MSTCN [11] and its more advanced relative MSTCN++ [27] without data augmentation. MVGA also improves the original ASFormer [43] producing the new state of the art performance on Breakfast. Applying MVGA on the features provided by Bridge-Prompt [26] and following the same training procedure as for the ASFormer gives the method Bridge-Prompt+MVGA with the best results on GTAE and 50Salads. In Tab. 6, we could not report Bridge-Prompt+MVGA performance on Breakfast, since the Bridge-Prompt model for action segmentation on Breakfast is not publicly available, and our own training of Bridge-Prompt on Breakfast gave poor results." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.72, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Video augmentation has been considered in the context of self-supervised learning (typically as a part of pretraining). However, a comparison with such methods is beyond our scope, because MVGA directly allows for the unified fully supervised training on a larger, augmented training dataset. In Tab. 7, we compare MVGA with some baseline video augmentation methods which also directly enable fully supervised learning, including Speed and C2F [34]. The former randomly selects certain action instances in each original training video, and performs \"speeding-up\" (i.e., frame subsampling) or \"slowing-down\" (i.e., frame upsampling with interpolation) of their temporal intervals," + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.476, + 0.892, + 0.598 + ], + "angle": 0, + "content": "and thus doubles the original training set. C2F randomly selects certain time intervals in every original training video. Then, for each selected interval, C2F assigns the dominant ground-truth action class with the largest temporal support in that interval, and also replaces all frame features within the interval with their max-pooled feature. As can be seen in Tab. 7, MVGA provides for better data augmentation for MS-TCN and ASFormer than Speed and C2F." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.625, + 0.618, + 0.64 + ], + "angle": 0, + "content": "7. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.655, + 0.892, + 0.867 + ], + "angle": 0, + "content": "We have specified video data augmentation for action segmentation within the reinforcement learning framework. Our approach generates new action transcripts and their corresponding new videos, as well as modifies the feature embedding of video frames. The transcript generation uses the efficient Monte-Carlo Tree Search to produce new, legal, high-likelihood action sequences. Optimal amount and temporal locations of feature changes in the video are learned with a two-agent actor-critic network. Our video augmentation in training of representative, state-of-the-art, convolutional and transformer-based action segmenters leads to their significant performance gains on the benchmark Breakfast, GTEA, and 50salads datasets, in comparison to their original training without video augmentation." + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.871, + 0.891, + 0.9 + ], + "angle": 0, + "content": "Acknowledgments This work was supported in part by DARPA MCS Award N66001-19-2-4035." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13512" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.47, + 0.171 + ], + "angle": 0, + "content": "[1] Hyemin Ahn and Dongheui Lee. Refining action segmentation with hierarchical video representations. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 16302-16310, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.173, + 0.472, + 0.228 + ], + "angle": 0, + "content": "[2] Nadine Behrmann, S Alireza Golestaneh, Zico Kolter, Juergen Gall, and Mehdi Noroozi. Unified fully and timestamp supervised temporal action segmentation via sequence to sequence translation. arXiv preprint arXiv:2209.00638, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.23, + 0.47, + 0.285 + ], + "angle": 0, + "content": "[3] Miriam Bellver Bueno, Xavier Giro-i Nieto, Ferran Marqués, and Jordi Torres. Hierarchical object detection with deep reinforcement learning. Deep Learning for Image Processing Applications, 31(164):3, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.287, + 0.472, + 0.342 + ], + "angle": 0, + "content": "[4] Juan C Caicedo and Svetlana Lazebnik. Active object localization with deep reinforcement learning. In Proceedings of the IEEE international conference on computer vision, pages 2488-2496, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.344, + 0.47, + 0.384 + ], + "angle": 0, + "content": "[5] Joao Carreira and Andrew Zisserman. Quo vadis, action recognition? a new model and the kinetics dataset. In CVPR, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.387, + 0.47, + 0.442 + ], + "angle": 0, + "content": "[6] Boyu Chen, Dong Wang, Peixia Li, Shuang Wang, and Huchuan Lu. Real-time actor-critic tracking. In Proceedings of the European conference on computer vision (ECCV), pages 318-334, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.444, + 0.47, + 0.486 + ], + "angle": 0, + "content": "[7] Min-Hung Chen, Baopu Li, Yingze Bao, Ghassan Al-Regib, and Zsolt Kira. Action segmentation with joint self-supervised temporal domain adaptation. In CVPR, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.487, + 0.47, + 0.555 + ], + "angle": 0, + "content": "[8] César Roberto de Souza, Adrien Gaidon, Yohann Cabon, Naila Murray, and Antonio Manuel López. Generating human action videos by coupling 3d game engines and probabilistic graphical models. International Journal of Computer Vision, 128(5):1505-1536, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.557, + 0.47, + 0.599 + ], + "angle": 0, + "content": "[9] César Roberto de Souza12, Adrien Gaidon, Yohann Cabon, and Antonio Manuel López. Procedural generation of videos to train deep action recognition networks. 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.601, + 0.47, + 0.641 + ], + "angle": 0, + "content": "[10] Li Ding and Chenliang Xu. Weakly-supervised action segmentation with iterative soft boundary assignment. In CVPR, June 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.643, + 0.47, + 0.685 + ], + "angle": 0, + "content": "[11] Yazan Abu Farha and Jurgen Gall. MS-TCN: Multi-stage temporal convolutional network for action segmentation. In CVPR, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.687, + 0.47, + 0.729 + ], + "angle": 0, + "content": "[12] Alireza Fathi, Xiaofeng Ren, and James M Rehg. Learning to recognize objects in egocentric activities. In CVPR 2011, pages 3281-3288. IEEE, 2011." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.73, + 0.47, + 0.771 + ], + "angle": 0, + "content": "[13] Shang-Hua Gao, Qi Han, Zhong-Yu Li, Pai Peng, Liang Wang, and Ming-Ming Cheng. Global2local: Efficient structure search for video action segmentation. In CVPR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.773, + 0.47, + 0.828 + ], + "angle": 0, + "content": "[14] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. Communications of the ACM, 63(11):139-144, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.83, + 0.47, + 0.871 + ], + "angle": 0, + "content": "[15] Junling Hu and Michael P Wellman. Nash q-learning for general-sum stochastic games. Journal of machine learning research, 4(Nov):1039-1069, 2003." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.47, + 0.902 + ], + "angle": 0, + "content": "[16] Chen Huang, Simon Lucey, and Deva Ramanan. Learning policies for adaptive tracking with deep feature cascades. In" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.472, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "Proceedings of the IEEE international conference on computer vision, pages 105-114, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.121, + 0.892, + 0.162 + ], + "angle": 0, + "content": "[17] Shariq Iqbal and Fei Sha. Actor-attention-critic for multiagent reinforcement learning. In International conference on machine learning, pages 2961–2970. PMLR, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.163, + 0.892, + 0.204 + ], + "angle": 0, + "content": "[18] Yuchi Ishikawa, Seito Kasai, Yoshimitsu Aoki, and Hirokatsu Kataoka. Alleviating over-segmentation errors by detecting action boundaries. In WACV, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.205, + 0.892, + 0.26 + ], + "angle": 0, + "content": "[19] Takashi Isobe, Jian Han, Fang Zhuz, Yali Liy, and Shengjin Wang. Intra-clip aggregation for video person re-identification. In 2020 IEEE International Conference on Image Processing (ICIP), pages 2336-2340. IEEE, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.261, + 0.892, + 0.302 + ], + "angle": 0, + "content": "[20] Levente Kocsis and Csaba Szepesvári. Bandit based montecarlo planning. In European conference on machine learning, pages 282-293. Springer, 2006." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.303, + 0.892, + 0.33 + ], + "angle": 0, + "content": "[21] Vijay Konda and John Tsitsiklis. Actor-critic algorithms. Advances in neural information processing systems, 12, 1999." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.331, + 0.892, + 0.371 + ], + "angle": 0, + "content": "[22] Hilde Kuehne, Ali Arslan, and Thomas Serre. The language of actions: Recovering the syntax and semantics of goal-directed human activities. In CVPR, 2014." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.372, + 0.892, + 0.413 + ], + "angle": 0, + "content": "[23] Colin Lea, Michael D. Flynn, Rene Vidal, Austin Reiter, and Gregory D. Hager. Temporal convolutional networks for action segmentation and detection. In CVPR, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.414, + 0.892, + 0.453 + ], + "angle": 0, + "content": "[24] Peng Lei and Sinisa Todorovic. Temporal deformable residual networks for action segmentation in videos. In CVPR, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.455, + 0.892, + 0.511 + ], + "angle": 0, + "content": "[25] Jie Li, Mingqiang Yang, Yupeng Liu, Yanyan Wang, Qinghe Zheng, and Deqiang Wang. Dynamic hand gesture recognition using multi-direction 3d convolutional neural networks. Engineering Letters, 27(3), 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.512, + 0.892, + 0.58 + ], + "angle": 0, + "content": "[26] Muheng Li, Lei Chen, Yueqi Duan, Zhilan Hu, Jianjiang Feng, Jie Zhou, and Jiwen Lu. Bridge-prompt: Towards ordinal action understanding in instructional videos. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 19880-19889, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.581, + 0.892, + 0.636 + ], + "angle": 0, + "content": "[27] Shi-Jie Li, Yazan AbuFarha, Yun Liu, Ming-Ming Cheng, and Juergen Gall. MS-TCN++: Multi-stage temporal convolutional network for action segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.637, + 0.892, + 0.719 + ], + "angle": 0, + "content": "[28] Xuan Liao, Wenhao Li, Qisen Xu, Xiangfeng Wang, Bo Jin, Xiaoyun Zhang, Yanfeng Wang, and Ya Zhang. Iteratively-refined interactive 3d medical image segmentation with multi-agent reinforcement learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 9394-9402, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.72, + 0.892, + 0.762 + ], + "angle": 0, + "content": "[29] Shiqi Lin, Tao Yu, Ruoyu Feng, Xin Li, Xin Jin, and Zhibo Chen. Local patch autoaugment with multi-agent collaboration. arXiv preprint arXiv:2103.11099, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.763, + 0.892, + 0.789 + ], + "angle": 0, + "content": "[30] Michael L Littman et al. Friend-or-foe q-learning in general-sum games. In ICML, volume 1, pages 322–328, 2001." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.79, + 0.892, + 0.831 + ], + "angle": 0, + "content": "[31] Ze Liu, Jia Ning, Yue Cao, Yixuan Wei, Zheng Zhang, Stephen Lin, and Han Hu. Video swim transformer. arXiv preprint arXiv:2106.13230, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.832, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[32] Chaofan Ma, Qisen Xu, Xiangfeng Wang, Bo Jin, Xiaoyun Zhang, Yanfeng Wang, and Ya Zhang. Boundary-aware supervoxel-level iteratively refined interactive 3d image segmentation with multi-agent reinforcement learning. IEEE Transactions on Medical Imaging, 40(10):2563-2574, 2020." + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13513" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.161 + ], + "angle": 0, + "content": "[33] Naima Otberdout, Mohammed Daoudi, Anis Kacem, Lahoucine Ballihi, and Stefano Berretti. Dynamic facial expression generation on hilbert hypersphere with conditional Wasserstein generative adversarial nets. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.163, + 0.47, + 0.204 + ], + "angle": 0, + "content": "[34] Dipika Singhania, Rahul Rahaman, and Angela Yao. Coarse to fine multi-resolution temporal convolutional network. In CVPR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.207, + 0.471, + 0.288 + ], + "angle": 0, + "content": "[35] Li Siyao, Weijiang Yu, Tianpei Gu, Chunze Lin, Quan Wang, Chen Qian, Chen Change Loy, and Ziwei Liu. Bailando: 3d dance generation by actor-critic gpt with choreographic memory. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11050-11059, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.291, + 0.471, + 0.359 + ], + "angle": 0, + "content": "[36] Sebastian Stein and Stephen J McKenna. Combining embedded accelerometers with computer vision for recognizing food preparation activities. In Proceedings of the 2013 ACM international joint conference on Pervasive and ubiquitous computing, pages 729-738, 2013." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.361, + 0.47, + 0.389 + ], + "angle": 0, + "content": "[37] Richard S Sutton and Andrew G Barto. Reinforcement learning: An introduction. MIT press, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.391, + 0.47, + 0.431 + ], + "angle": 0, + "content": "[38] Liangliang Wang, Lianzheng Ge, Ruifeng Li, and Yajun Fang. Three-stream cnns for action recognition. Pattern Recognition Letters, 92:33-40, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.433, + 0.469, + 0.486 + ], + "angle": 0, + "content": "[39] Yuqing Wang, Zhaoliang Xu, Xinlong Wang, Chunhua Shen, Baoshan Cheng, Hao Shen, and Huaxia Xia. End-to-end video instance segmentation with transformers. In CVPR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.489, + 0.469, + 0.53 + ], + "angle": 0, + "content": "[40] Zhenzhi Wang, Ziteng Gao, Limin Wang, Zhifeng Li, and Gangshan Wu. Boundary-aware cascade networks for temporal action segmentation. In ECCV, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.532, + 0.469, + 0.586 + ], + "angle": 0, + "content": "[41] Dongxu Wei, Xiaowei Xu, Haibin Shen, and Kejie Huang. Gac-gan: A general method for appearance-controllable human video motion transfer. IEEE Transactions on Multimedia, 23:2457-2470, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.589, + 0.469, + 0.657 + ], + "angle": 0, + "content": "[42] Di Wu, Junjun Chen, Nabin Sharma, Shirui Pan, Guodong Long, and Michael Blumenstein. Adversarial action data augmentation for similar gesture action recognition. In 2019 International Joint Conference on Neural Networks (IJCNN), pages 1-8. IEEE, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.66, + 0.469, + 0.699 + ], + "angle": 0, + "content": "[43] Fangqiu Yi, Hongyu Wen, and Tingting Jiang. AS-Former: Transformer for action segmentation. CoRR, arXiv 2110.08568, 2021." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.699 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.52, + 0.957 + ], + "angle": 0, + "content": "13514" + } + ] +] \ No newline at end of file diff --git a/2023/Markov Game Video Augmentation for Action Segmentation/3ebb7b09-a6e7-4446-89ff-eb9741fd0b7f_origin.pdf b/2023/Markov Game Video Augmentation for Action Segmentation/3ebb7b09-a6e7-4446-89ff-eb9741fd0b7f_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..0551bbf367f199303ef0de07c97033a3256e7efd --- /dev/null +++ b/2023/Markov Game Video Augmentation for Action Segmentation/3ebb7b09-a6e7-4446-89ff-eb9741fd0b7f_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:8ca84fb3e083d636ed80fa6a539bd78d6ffb60f341043034b8b95ac9fd6c6333 +size 1073930 diff --git a/2023/Markov Game Video Augmentation for Action Segmentation/full.md b/2023/Markov Game Video Augmentation for Action Segmentation/full.md new file mode 100644 index 0000000000000000000000000000000000000000..9dac9c24fa83062db132c3f1624d71dbb0e21208 --- /dev/null +++ b/2023/Markov Game Video Augmentation for Action Segmentation/full.md @@ -0,0 +1,301 @@ +# Markov Game Video Augmentation for Action Segmentation + +Nicolas Aziere + +Oregon State University + +azieren@oregonstate.edu + +Sinisa Todorovic + +Oregon State University + +sinisa@oregonstate.edu + +# Abstract + +This paper addresses data augmentation for action segmentation. Our key novelty is that we augment the original training videos in the deep feature space, not in the visual spatiotemporal domain as done by previous work. For augmentation, we modify original deep features of video frames such that the resulting embeddings fall closer to the class decision boundaries. Also, we edit action sequences of the original training videos (a.k.a. transcripts) by inserting, deleting, and replacing actions such that the resulting transcripts are close in edit distance to the ground-truth ones. For our data augmentation we resort to reinforcement learning, instead of more common supervised learning, since we do not have access to reliable oracles which would provide supervision about the optimal data modifications in the deep feature space. For modifying frame embeddings, we use a meta-model formulated as a Markov Game with multiple self-interested agents. Also, new transcripts are generated using a fast, parameter-free Monte Carlo tree search. Our experiments show that the proposed data augmentation of the Breakfast, GTEA, and 50Salads datasets leads to significant performance gains of several state of the art action segmenters. + +# 1. Introduction + +This paper presents a new data augmentation framework for fully supervised action segmentation of untrimmed videos. Action segmentation is a basic vision problem. Despite recent tremendous advances in terms of new action segmenters and learning strategies, there is relatively slow progress in increasing the size of existing benchmark datasets. In comparison with peer datasets for action recognition or image classification, available benchmarks for action segmentation are significantly smaller. This presents challenges in training of recent action segmenters which show tendency to overfit on small datasets [11, 43, 40]. However, compiling large datasets is difficult, due to, in part, high costs of manual annotation of action segments. + +We propose to augment existing datasets with newly gen + +erated video sequences, such that the resulting data augmentation enables more robust training and hence improves performance of action segmenters. Our approach is agnostic of a particular model for action segmentation, and expects that the segmenter has been pre-trained on the original training dataset to predict action classes of video frames. + +Augmentation of video data has been mostly considered in the spatiotemporal, visual domain [38, 25, 19], where a human expert would heuristically specify the amount and type of data manipulation (e.g., subsampling, cropping, flipping of video frames) that are useful in training. While these approaches show great success, it is hard to formalize them in a principled manner. Others learn to generate new videos [9, 8, 42, 41], but the results are not sufficiently realistic yet, and hence would require domain adaptation if used for data augmentation in action segmentation. + +Our key novelty is that we augment the original training videos directly in the deep feature space, unlike most previous work. As shown in Fig. 1 (top left), for augmentation, we modify original deep features of video frames at the input, such that the resulting embeddings fall closer to the class decision boundaries. Thus, by construction, we enforce that the augmented features be more challenging for learning, and in this way subsequently enable more robust training of the action segmenter. In addition, Fig. 1 (top right) illustrates that we also edit action sequences of the original training videos (a.k.a. transcripts) by inserting, deleting, and replacing actions, such that the resulting transcripts are close in edit distance to the groundtruth ones. Since the generated transcripts are kept similar to the originals, they are expected to be meaningful (i.e., legal) and provide a greater variety of legal action sequences than seen in the original training set. This is especially important for those application domains where some transcripts of interest are naturally rare and hence underrepresented in the original training dataset. + +For the proposed augmentation of frame embeddings in the deep feature space, we specify a deep residual metamodel, as shown in Fig. 1 (bottom left). The meta-model takes deep features of frames at the input and predicts an optimal amount of feature modifications - i.e., offset fea + +![](images/07e320007427c9b028287eb228d18bdca74202a43981638ece08e9a5d1256c40.jpg) +Figure 1. The proposed two-pronged data augmentation: (top and bottom left) Original deep features of frames at the input of a meta-model are modified to fall closer to class decision boundaries of the pretrained action segmenter. Alternative frameworks are considered for training the meta-model, including Gaussian noise, or supervised learning of a Temporal CNN, or reinforcement learning of an Actor-Critic network. (top and bottom right) The original action transcripts of training videos are modified by inserting, replacing, and removing actions, while ensuring a small edit distance between the newly generated transcripts and the originals. For training the meta-model for transcript augmentation, we consider supervised learning and alternatively a Monte Carlo tree search. + +tures which are added to the original frame features, resulting in augmented embeddings. For training the meta-model, we consider both RL (Fig. 1 (bottom left)) and supervised learning. From our experiments, RL proves to be a more reliable paradigm. + +Supervised learning of the proposed meta-model faces a fundamental challenge. As a direct consequence of performing data augmentation in the deep feature space, there is no reliable oracle which would provide supervision for the optimal amount of feature modifications. The only available oracle is the pre-trained action segmentation model which could predict action labels of the augmented frame embeddings, and the incurred loss could be used for training the meta-model. The action segmentation model provides only pseudo-labels for generated data – not ground-truth labels – and hence a fully-supervised training of our meta-model could suffer from noisy pseudo-labels. + +An alternative is to resort to reinforcement learning (RL) due to the following advantages. First, it allows us to sequentially modify frame features, where previous modifications define a state in which RL estimates an optimal modification of the next frames. Learning of the proposed sequential feature augmentation is expected to be more reliable, especially for long video sequences, than learning how to optimally modify all frame embeddings at once. RL produces an optimal policy which would account for temporal dependence between frame embeddings, and hence make them suitable for action segmentation models with large temporal receptive fields (like MS-TCN or AS-Former). Second, RL is expected to provide for a more sta + +ble training of our meta-model by optimizing the expected reward over a policy of feature modifications, in comparison with the aforementioned minimization of the unreliable loss of the pretrained action segmenter on particular feature modifications. Third, RL is known to be very effective for problems with a large, continuous, output space, as is our case of predicting offset features in the deep feature space. Finally, RL is known to successfully address non-stationary environments with the distribution shift between training and test sets [37], which exactly characterizes our problem statement where data augmentation is aimed at bridging the distribution shift. + +Within the RL framework, for modifying frame embeddings, we formulate the meta-model as a Deep Actor-Critic Network for learning policies of two self-interested agents in a Markov Game. Also, for generating new transcripts, we use a fast, parameter-free Monte Carlo tree search. We call our approach Markov Game Video Augmentation (MVGA). + +Our experimental evaluation shows significant performance gains of recent convolutional and transformer-based action segmenters when our MVGA is used to augment the Breakfast, GTEA, and 50Salads datasets. Interestingly, MVGA enables the convolutional model MS-TCN [11, 27] achieve close performance to that of the significantly more complex (and more recent) ASFormer [43]. + +In the following, Sec. 2 reviews closely related work, Sec. 3 gives an overview of MVGA, Sec. 4 specifies our transcript augmentation, Sec. 5 formalizes our frame-feature augmentation, and Sec. 6 presents our results. + +# 2. Related Work + +This section reviews closely related work on fully supervised action segmentation and video data augmentation. + +A family of temporal convolution models [10, 23, 24, 11, 40, 27, 34] have been studied for action segmentation. Some of these models use gradual temporal pooling for overcoming oversegmentation [10, 23, 24, 34], and others integrate reasoning about action boundaries [40, 18]. As representatives of this family, in our experiments, we consider MS-TCN [11, 27] and boundary-aware BCN [40] both of which consist of multiple stages of temporal convolution layers. Recent transformer-based models [43, 31, 39, 2] outperform temporal convolution models. Among these transformers, for evaluation, we consider ASFormer [43]. Both MS-TCN and ASFormer use standard I3D deep features [5]) of video frames as input. We also study a version of ASFormer with more informative frame embeddings [26]. + +Video augmentation in the visible space-time domain, such as, e.g., temporal cropping of frames [38, 25] or random cropping/removing/flipping of frames in a training mini-batch [19] have become standard practice in action recognition, person re-ID, and hand gesture recogni + +tion. Other data augmentation methods have also been used, including pooling frame features within a window of variable length [34]. For video augmentation, some approaches generate simulated videos with video-game engines [9, 8], or GANs [14, 42, 41, 33]. However, there is still a large domain gap between such simulated and real videos, which limits the utility of these methods for data augmentation. + +Reinforcement learning has been used for addressing various vision problems, including 3D image segmentation [28, 32], image classification [29], object detection [3, 4], and tracking [6, 16]. To the best of our knowledge, video data augmentation for action segmentation has never been formulated within the reinforcement learning framework. + +# 3. Overview of MVGA + +In this and following two sections, we focus on our reinforcement learning formulation of the proposed data augmentation. The supervised learning formulation is described in Sec. 6. Fig. 2 shows an overview of our approach which consists of the following four steps. The first step pre-trains an action segmenter on a given training dataset $\mathcal{D}$ . A training video of length $T$ in $\mathcal{D}$ is given by its deep features for every frame $\mathcal{X} = \{x_t : t = 1, \dots, T\}$ , where $x_t \in \mathbb{R}^{d_{\mathrm{in}}}$ ( $d_{\mathrm{in}} = 2048$ for standard I3D features [5]), and the ground-truth action classes $\mathcal{Y} = \{y_t : t = 1, \dots, T\}$ , where $y_t \in \mathbb{Y}$ and $\mathbb{Y}$ is a set of action classes. After pretraining, the action segmenter $f_{\theta}$ can be used to predict action classes of video frames $\hat{\mathcal{Y}} = f(\mathcal{X}; \theta)$ . + +The second step generates new transcripts and their corresponding videos. We use the UCT algorithm [20] to first efficiently construct a tree, whose paths from the root to leaves represent legal transcripts, and then select optimal paths. For every new transcript, a new video is constructed by copying appropriate action segments from real videos in $\mathcal{D}$ to the new video following the action sequence of the new transcript. + +The third step augments features of the original and new videos with the Actor and Critic networks, which gives the augmented dataset $\mathcal{D}'$ . The Actor predicts how much and where to modify features in the input video. The Critic estimates the expected rewards for the Actor. Both Actor and Critic are learned using the pre-trained $f_{\theta}$ as oracle. + +The fourth step fine-tunes $f_{\theta}$ such that every mini-batch consists of videos from both $\mathcal{D}$ and $\mathcal{D}'$ . + +In the following, we specify the second and third steps. + +# 4. New Transcript and Video Generation + +From $\mathcal{D}$ , we generate new transcripts and their corresponding new videos. The new transcripts should be semantically meaningful, i.e., legal. This is enforced by requiring that the new transcripts have: (i) similar lengths as the original transcripts; and (ii) high likelihoods of consec + +utive pairs of action classes. Our experiments suggest that auto-regressive models - e.g., a recurrent-neural network (RNN) or Transformer network [35] - provide poor transcript generation, since they require large training datasets and hence have limited utility for our target settings where data augmentation is needed to address lack of data. Therefore, in this section, we focus on an alternative framework - parameter-free Monte-Carlo Tree Search (MTCS), where the space of transcripts is efficiently represented by a tree. We first construct the tree, and then identify its optimal path. + +# 4.1. MTCS for New Transcript Generation + +In the tree of transcripts, the root represents the dummy "start" of action sequences. The root's descendants sequentially add action classes to the transcripts until leaf nodes, which represent the dummy "end". A node $v$ represents the last action class of the path $\pi_v$ from the root to $v$ , $\pi_v = \{\text{"start", } y_1, \dots, y_v}\}$ , where $y_v \in \mathbb{Y}$ or $y_v = \text{"end"}$ if $v$ is a leaf node. Each node is assigned a weight, $w(v)$ , specified as the joint likelihood of the corresponding path: + +$$ +w (v) = p \left(\left| \pi_ {v} \right|\right) \prod_ {\left(u, u ^ {\prime}\right) \in \pi_ {v}} p \left(y _ {u ^ {\prime}} \mid y _ {u}\right), \tag {1} +$$ + +where $p(|\pi_v|)$ is a prior of the transcript length, $u'$ is a child of $u$ along $\pi_v$ , and $p(y_{u'} | y_u)$ denotes the transition probability of consecutive actions. In the special case, $p(y_{u'} | "start")$ and $p("end" | y_u)$ represent the priors that the transcript begins and ends with classes $y_{u'}, y_u \in \mathbb{Y}$ . Both $p(|\pi_v|)$ and $p(y_{u'} | y_u)$ are estimated from $\mathcal{D}$ . For $p(|\pi_v|)$ we learn the Poisson distribution, and for $p(y_{u'} | y_u)$ we estimate the frequency of the corresponding class transitions in $\mathcal{D}$ . + +The tree is constructed iteratively using the well-known UCT algorithm [20] which balances a trade-off between exploitation and exploration. In each iteration, the root is sequentially expanded with a path of optimal descendants until the dummy "end" leaf or the maximum tree depth is reached. We do not allow illegal expansions, i.e., a path is guaranteed to consist of class transitions seen in $\mathcal{D}$ . Suppose a path has reached node $u$ without meeting the stopping criterion. Then, UCT adds to the path the optimal node $u'$ from a subset of children, $\mathrm{ch}(u) \subset \mathrm{Ch}(u) = \{u': p(y_{u'} | y_u) > 0\}$ : + +$$ +u ^ {\prime} = \arg \max _ {v \in \operatorname {c h} (u)} \left[ w (v) + c \sqrt {\frac {2 \log n (u)}{n (v)}} \right] \tag {2} +$$ + +where $\operatorname{ch}(u)$ is randomly sampled $50\%$ of $\operatorname{Ch}(u)$ to enable exploring alternative paths; $w(v)$ is given by (1); $c = \frac{1}{\sqrt{2}}$ is the exploration-exploitation trade-off parameter; and $n(v)$ is the number of paths in the current tree that include node $v$ . As the tree iteratively grows, the value of $n(v)$ keeps changing for every node, which enables exploring less visited nodes in the space of transcripts even if $w(v)$ is small. + +![](images/a14584df1770b75c98816c93bbaa46f6a2becf24c61097e5214b864531491a21.jpg) +Figure 2. Our MVGA consists of four steps. 1-An action segmentation model is pre-trained using the original training set. 2-New transcripts are generated by selecting optimal paths in a UCT tree [20] of legal transcripts. For every new transcript, a new video is constructed by copying instances of action classes in the new transcript from real videos. 3- Features of the original and constructed new videos are augmented with the Actor and Critic networks. The Actor predicts the amount and location of feature modifications in the video. The Critic estimates the expected rewards for the Actor's two predictions. Both Actor and Critic are learned using the pre-trained action segmenter as oracle. 4- The action segmenter is fine-tuned on the original and augmented training videos. + +After 1000 tree-growing iterations, the node $v^{*}$ with the highest likelihood $v^{*} = \arg \max_{v} w(v)$ in the tree uniquely identifies the newly generated transcript $\pi_{v^{*}}$ . For generating another transcript, we construct another tree anew. + +# 4.2. Generating New Videos of New Transcripts + +Given a new transcript, $\pi$ , we sequentially construct a new video with deep features (e.g., I3D [5]) following the ordering of action classes in $\pi$ . It is worth emphasizing that our video generation occurs directly in the deep feature space. We begin by selecting a video $\mathcal{X}_0 \in \mathcal{D}$ whose ground-truth transcript has the smallest edit distance to $\pi$ . From $\mathcal{X}_0$ , we remove all action segments that are not represented in $\pi$ , resulting in our initial new video $\mathcal{X}_0'$ . For action classes that are present in $\pi$ but missing in $\mathcal{X}_0'$ , we identify the second closest video $\mathcal{X}_1 \in \mathcal{D}$ with these missing actions, and copy their respective temporal intervals to the appropriate locations in the new video, resulting in $\mathcal{X}_1'$ . This is repeated until the entire $\pi$ is fully represented by $\mathcal{X}_g'$ , $g = 0, 1, 2, \ldots$ . Note that $\mathcal{X}_g'$ keeps the original lengths of action instances found in real videos, which ensures temporal coherence of every action in $\mathcal{X}_g'$ . A pseudo-code of the proposed video generation is given in the supplement. + +# 5. Augmentation of Frame Features + +Features of both original and new videos are augmented by a Markov Game (MG) [15, 30, 37]. Since MG is a well-studied framework and we do not claim novelty in our particular formulation, below we rely that the reader is al- + +ready familiar with the motivation and main concepts of MG. Our MG consists of two agents which sequentially take independent actions causing state changes of a fully observable environment. The environment at step $k$ is defined by state $s_k = (\mathcal{X}_k, \mathcal{M}_k)$ , where $\mathcal{X}_k = \{x_{k,t} : t = 1, \dots, T\}$ is the set of current video frame features, and $\mathcal{M}_k = \{m_{k,t} : t = 1, \dots, T\}$ is a binary mask assigned to the video frames, $m_{k,t} \in \{0,1\}$ , for keeping the record which frames have been already modified. Given $s_k$ , the two agents follow their respective policies, $\mu^1$ and $\mu^2$ , to take actions $a_k^1 = \mu^1(s_k) \in \mathcal{A}^1$ and $a_k^2 = \mu^2(s_k) \in \mathcal{A}^2$ . $\mathcal{A}^1$ is a continuous action space of agent 1, where $a_k^1 = \{a_{t,k}^1 : t = 1, \dots, T\}$ represents the amount of feature augmentation, i.e., offset features. $\mathcal{A}^2$ is a discrete action space of agent 2 for selecting video frames for augmentation, $a_k^2 \in \{0,1\}^T$ , where $a_{t,k}^2 = 0$ means that the frame $t$ will not be augmented in step $k$ . $a_k^1$ and $a_k^2$ cause the environment to change to next state $s_{k+1}$ , which incurs the respective two rewards $R_k^1 = R^1(s_k, s_{k+1}, f_\theta)$ and $R_k^2 = R^2(s_k, a_2^k)$ . Our goal is to learn $\mu^1$ and $\mu^2$ so as to maximize the agents' action-value functions given by: + +$$ +Q ^ {i} (s, a) = \mathbb {E} \left[ \sum_ {k \geq 0} (\gamma) ^ {k} R _ {k} ^ {i} \mid \mu^ {i}, a _ {0} ^ {i} = a, s _ {0} = s \right], i = \{1, 2 \} \tag {3} +$$ + +where $\mathbb{E}[\cdot ]$ denotes expected value, $\gamma = 0.99$ is the discount factor raised to the power of $k$ , $s\in S$ , and $a\in \mathcal{A}^i$ . + +For a given video, MG starts from the initial state $s_0 = (\mathcal{X}_0, \mathcal{M}_0)$ , with the original frame features and all-zero + +mask, $\mathcal{X}_0 = \mathcal{X}$ and $\mathcal{M}_0 = \{0\}^T$ . In state $s_k$ , the two agents take their respective actions, which gives $s_{k + 1}$ specified as + +$$ +\mathcal {X} _ {k + 1} = \left\{x _ {t, k} + a _ {t, k} ^ {2} \left(a _ {t, k} ^ {1} + \epsilon\right): t = 1, \dots , T \right\}, \tag {4} +$$ + +$$ +\mathcal {M} _ {k + 1} = \mathcal {M} _ {k} \vee a _ {k} ^ {2}, \tag {5} +$$ + +where $\vee$ is the logical OR operator, and $\epsilon \in \mathbb{R}^{d_{\mathrm{in}}}$ is noise sampled from the zero-mean and unit-variance Gaussian distribution. $\epsilon$ enables an exploration of $\mathcal{A}^1$ and provides a way to generate multiple, distinct, augmented features from the same initial state $s_0$ . From (4), only frames selected by $a_k^2$ get updated with the corresponding offset features $(a_k^1 + \epsilon)$ . Also, from (5), mask $\mathcal{M}_k$ keeps the record of previously selected frames for augmentation. + +MG stops as soon as one of the following happens (experimentally optimized): after $k = 10$ steps, or when $95\%$ of the video has been augmented, $\sum_{t=1}^{T} m_{t,k} \geq 0.95T$ . + +# 5.1. Two Rewards for Feature Augmentation + +The policy of agent 1, $\mu^1$ , is learned to augment original features, such that they become more challenging for the pre-trained action segmenter, $f_{\theta}$ , and thus provide for a more robust subsequent training of $f_{\theta}$ on the augmented training dataset. This is enforced by specifying the following reward $R_k^1 = R^1(s_k, s_{k+1}, f_{\theta})$ . Let $\hat{y}_t$ and $\hat{y}_t'$ denote the top two scoring class predictions for $x_{t,k}$ by $f_{\theta}$ , $\hat{y}_t = \arg \max_{y \in \mathbb{Y}} p(y|x_{t,k};\theta)$ and $\hat{y}_t' = \arg \max_{y \in \mathbb{Y} \setminus \{\hat{y}_t\}} p(y|x_{t,k};\theta)$ . We penalize agent 1 with a negative reward whenever $a_k^1$ causes $f_{\theta}$ to make a wrong prediction, $\hat{y}_t \neq y_t$ . We assign a positive reward to agent 1 when $f_{\theta}$ 's prediction is equal to the ground truth, $\hat{y}_t = y_t$ , and reduce this positive reward if the feature augmentation is not challenging enough for $f_{\theta}$ . The positive reward reduction is proportional to $f_{\theta}$ 's confidence in its prediction, specified as a difference between its top two scoring predictions, $\kappa = [p(\hat{y}_t|x_{t,k};\theta) - p(\hat{y}_t'|x_{j,k};\theta)]$ , $0 < \kappa \leq 1$ . Hence, when confidence $\kappa$ is large and close to 1, the positive reward for agent 1 is maximally reduced as + +$$ +R _ {k} ^ {1} = \frac {1}{\| a _ {k} ^ {2} \|} \sum_ {t \in \mathcal {T} (a _ {k} ^ {2})} r ^ {1} (x _ {t, k + 1}, f _ {\theta}), +$$ + +$$ +r ^ {1} \left(x _ {t, k}, f _ {\theta}\right) = \left\{ \begin{array}{l l} 1 - \left[ p \left(\hat {y} _ {t} \mid x _ {t, k}; \theta\right) - p \left(\hat {y} _ {t} ^ {\prime} \mid x _ {t, k}; \theta\right) \right], & \text {i f} \hat {y} _ {t} = y _ {t} \\ - 1 & , \text {i f} \hat {y} _ {t} \neq y _ {t} \end{array} \right. \tag {6} +$$ + +where $\mathcal{T}(a_k^2)$ returns the set of frames where $a_{t,k}^2 = 1$ . + +For the policy of agent 2, $\mu^2$ , we specify the following three requirements: (i) $\mu^2$ should not select frames which have already been augmented in the previous MG steps; (ii) frame selection should be local at each MG step and focus only on a very few action instances in the video (and in this way make learning of $\mu^1$ easier); and (iii) selected temporal + +intervals should maximally overlap the ground-truth action instances. These three requirements are enforced by specifying the following reward: + +$$ +R _ {k} ^ {2} = \left\{ \begin{array}{c} \sum_ {\tau} \frac {| \tau \cap a _ {k} ^ {2} |}{| \tau |}, \text {i f} \sum_ {t} a _ {t, k} ^ {2} m _ {t, k} < \alpha \text {a n d} \| a _ {k} ^ {2} \| < \frac {T}{2} \\ - 1, \text {o t h e r w i s e} \end{array} \right. \tag {7} +$$ + +$\tau$ is the ground-truth mask of actions over frames, and enforces that each iteration of the video augmentation covers the entire time interval of an action rather than randomly scattered frames. $\alpha = 0.4T$ is an experimentally optimized threshold which allows a flexible frame selection of up to $40\%$ of the past $\mathcal{M}_k$ . From (7), agent 2 is penalized when selects more than a half of the video for augmentation. + +# 5.2. Learning the Policies for Feature Augmentation + +To learn $\mu^1$ and $\mu^2$ , we design an Actor-Critic model with a decentralized-actor deep network for computing the agents' actions, and a centralized-critic deep network for efficiently estimating action-value functions $\hat{Q}^1$ and $\hat{Q}^2$ , as shown in Fig. 3. The Actor-Critic framework has been demonstrated effective for continuous agent-action spaces and when the agents have individual rewards [17], as in our case. In general, decentralizing the actor network helps increase stationarity of environments with self-interested agents [37]. The centralized critic network is suitable because it allows relevant information from all of the agents to be shared toward estimating each agent's expected reward. + +As can be seen in Fig. 3, the input to the actor network, $s_k = (\mathcal{X}_k, \mathcal{M}_k)$ , is passed through a backbone, specified as a multi-stage temporal convolutional neural network (TCN) [11], in order to estimate the latent (deep) representation of $s_k$ . Then, two distinct 1-stage TCNs take this latent representation as input and compute the frame selection + +![](images/ac11775c1bb28e9621f1c50e5b0fac05631f9f124203b8fe256f102618230d56.jpg) +Figure 3. Actor-Critic model for learning policies $\mu^1$ and $\mu^2$ consists of several stages of temporal convolution network (TCN). The actor network predicts feature augmentation, and the centralized critic estimates the expected rewards for each policy. + +$a_2^k$ and feature offsets of the selected frames $a_k^1$ . Finally, the predicted $a_k^1$ , $a_2^k$ , and latent feature of $s_k$ are passed to the centralized critic - specifically, a 2-stage TCN - to estimate the expected rewards $\hat{Q}_k^1 = \hat{Q}^1 (s_k,a_k^1,a_k^2)$ and $\hat{Q}_k^2 = \hat{Q}^2 (s_k,a_k^1,a_k^2)$ of $\mu^1$ and $\mu^2$ . + +Parameters of the proposed actor-critic deep architecture are learned using the standard temporal difference learning [21]. The critic learns to iteratively simulate the action-value function, $\hat{Q}_k^i$ , $i = \{1, 2\}$ , which is later used to update parameters of the actor network. To this end, we minimize the following loss of the critic network: + +$$ +L _ {C} = \sum_ {i \in \{1, 2 \}} \left(R _ {k} ^ {i} + \gamma \hat {Q} _ {k + 1} ^ {i} - \hat {Q} _ {k} ^ {i}\right) ^ {2}, \tag {8} +$$ + +where $R_{k}^{i}$ is given by (6) and (7), and $\gamma$ is the discount factor. The actor network is learned with the following loss: + +$$ +L _ {A} ^ {i} = \left\| a _ {k} ^ {i} \right\| _ {2} ^ {2} \cdot \left(R _ {k} ^ {i} + \gamma \hat {Q} _ {k + 1} ^ {i} - \hat {Q} _ {k} ^ {i}\right) ^ {2}, i = \{1, 2 \}. \tag {9} +$$ + +A proof in [37] shows that minimizing $L_{C}$ and $L_{A}$ in (8) and (9) optimizes $\mu^{1}$ and $\mu^{2}$ so they manage to achieve maximal rewards $R^{1}$ and $R^{2}$ given by (6) and (7), as desired. + +# 6. Results + +Datasets include three benchmarks: Breakfast [22], GTEA [12], and 50Salads [36]. For each dataset, we precompute the standard I3D frame features without any self-supervision, fine-tuning, or data augmentation, as in [11]. Breakfast has 1712 videos with 48 action classes, GTEA shows 7 complex activities, each specified in terms of 11 action classes including the background class. 50Salads consists of 50 videos with 17 action classes. For Breakfast, GTEA, and 50Salads, we perform the standard 4-fold, 4-fold, and 5-fold cross validation, respectively. + +Metrics. Mean-of-Frame (MoF) is the average framework classification accuracy. Edit score counts edit operations to make the predicted and ground-truth sequences equivalent. F1 score counts true positives when a temporal intersection between the predicted and ground-truth segments is $10\%$ , $25\%$ and $50\%$ , denoted as F1@10,25,50. + +Implementation details. The Actor-Critic has the same layers as MS-TCN [11]. One stage consists of 10 convolution layers with an increasing dilation rate and feature maps with size 128. The mask backbone and feature backbone each represents a 1-stage TCN. Their outputs are, first, concatenated, then, passed to a 4-stage MS-TCN, and, finally, input to the agents' heads. Agent 1's head is a 2-stage MS-TCN. Agent 2's head is a 1-stage TCN. The critic network is a 2-stage MS-TCN. The learning rate for the actor-critic training is 0.0001. Our training of the meta-model is run for + +30 epochs. The NMS threshold is set to 0.5, and the minimum IOU is set to 0. The discount factor $\gamma = 0.99$ . The policy training on Tesla-V100s for GTEA takes 3 hours. The MCTS algorithm runs 1000 node expansions in a couple of seconds. The maximum tree width is 200. The maximum tree depth is $\hat{\lambda} + 2\sqrt{\hat{\lambda}}$ where $\hat{\lambda}$ is the average transcript length of the training set. The number of epochs in the fine-tuning on the original and augmented data is 50 epochs for MS-TCN, 100 epochs for ASFormer, and 50 epochs for BCN. The meta-training of the meta-model increases complexity compared to baseline approaches. It is important to separate the time for training an action segmentation model, and the time for our meta-training. Our meta-training can be viewed as a part of the dataset preparation, which takes significantly less time than manually collecting and annotating real videos. + +# 6.1. Ablation Studies of MS-TCN on GTEA + +The training dataset size. Tab. 1 reports how MS-TCN performance on GTEA changes as a function of two variables: (i) the number of training transcripts; and (ii) the total number of original and augmented videos – both expressed as the increase factor of the original set. Tab. 1 shows that when the original set of training videos is tripled such that there are $20\%$ of new transcripts, MS-TCN achieves the best performance for all of the metrics, and this setting is used in the sequel. Too many augmentations using the same input video leads to similar data outputs, and consequently to overfitting in training of an action segmentation model. Note that testing the transcript augmentation as a standalone contribution is inappropriate and reduces performance (second row), since new transcripts need to be realized as new videos. These new videos are Frankenstein-like constructs from multiple real videos, and hence have highly unrealistic action transitions, and incoherent and sometimes impossible human motions. Therefore, the new videos require additional frame-feature augmentation to provide useful data augmentation. + +Alternatives for generating transcripts. Tab. 2 compares two alternative methods for generating transcripts – namely, auto-regression and our UCT – in terms of: (i) edit distance to the ground-truth transcripts, and (ii) expected reward given by (1). The two metrics are averaged over the top $10\%$ and $20\%$ of generated transcripts that are the closest to the ground-truth transcripts. The auto-regressive model is a Transformer Network [35] trained with the cross-entropy loss to predict the next action class given an input sequence of action classes. From Tab. 2, our UCT generates transcripts which are more similar to the ground-truth ones than those produced by auto-regression. Also, the average likelihoods for UCT and ground truth are nearly the same. + +RL vs Non-RL for frame-feature augmentation. Tab. 3 compares the proposed reinforcement learning and + +
#TranscriptsTrain. set sizeF1@10,25,50EditMoF
1×1×87.384.972.482.078.0
1.1×1×85.281.169.780.074.9
1×2×89.888.577.686.879.5
1.1×2×90.588.677.987.178.9
1.2×3×90.988.279.288.879.6
1.2×4×89.187.778.989.079.7
1.2×5×89.087.075.685.778.2
+ +Table 1. MS-TCN performance on GTEA as a function of the number of training transcripts, and the number of original and augmented videos used for training -both expressed as the increase factor of the original training set. When our augmentation triples the set of training videos such that there are $20\%$ of newly generated transcripts, MS-TCN achieves the best performance. The top row is without any augmentation, and the second from the top row is for only feature augmentation without new transcripts. + +
MethodEdit dist. (%) Top 10%Edit dist. (%) Top 20%Likelihood Top 20%
Auto-regression19.522.00.59e-4
UCT14.015.21.41e-4
Ground truth--1.45e-4
+ +Table 2. Comparison of two alternative transcript generation methods – auto-regression by a Transformer Network [35], and our proposed UCT – in terms of an average edit distance between the generated and ground-truth transcripts for GTEA, and their average likelihood given by (1). The two metrics are averaged over the top $10\%$ and $20\%$ of generated transcripts closest to the ground-truth. + +
Frame AugmentationF1@10,25,50EditMoF
No augmentation [11]85.883.469.879.076.3
Noise85.783.271.979.677.5
Non-RL (Seq)83.180.969.176.276.5
Non-RL (All)83.981.570.477.677.7
Our RL-based90.988.279.288.879.6
+ +Table 3. MS-TCN performance on GTAE, when using the best data augmentation setting given in Tab. 1, and for alternative strategies of frame-feature augmentation. Supervised learning in "Non-RL" decreases the performance of MS-TCN. + +
PoliciesF1@10,25,50EditMoF
μ1/1088.585.074.783.878.2
μ1/2087.484.874.184.577.8
μ1/μ290.988.279.288.879.6
+ +an alternative supervised learning for frame-feature augmentation, when using the best data augmentation setting given in Tab. 1. We consider several baselines. "Noise" refers to simply adding Gaussian noise with zero mean and 0.01 variance to the original deep features of frames, as the original I3D features have an average value of 0.2 and variance 0.06. From Tab. 3, such a frame-feature augmentation with Gaussian noise barely has any effect on MS-TCN's performance. "Non-RL" is another baseline that uses su + +Table 4. MS-TCN performance on GTAE for the proposed multiagent $(\mu_{1} / \mu_{2})$ and the alternative single-agent $(\mu_{1} / 10$ or $\mu_{1} / 20)$ + +
Class transition2, 52, 75, 98, 1010, 4
# Original dataset11233
# Augmented dataset22355
+ +Table 5. Count of the least represented action transitions in the original and augmented training sets of GTEA. + +pervised learning for training the meta-model, as depicted in Fig. 1 (bottom left). In "Non-RL" the meta-model is a 1-stage TCN which outputs the offset feature for a given original feature at the input. As shown in Fig. 1 (bottom left), the resulting augmented feature is then passed to the pre-trained action segmenter. The meta-model is trained based on the cross-entropy loss of the pre-trained action segmenter, which serves as an oracle to ensure that the augmented feature remains in the action class of the original frame feature. For "Non-RL", we also regularize the resulting augmented feature to be different from the original feature with the standard contrastive loss. Moreover, we study two versions of "Non-RL" - one where all features of the entire video are modified at once, called "Non-RL (All)"; and the other with a sequential modification of frame features one action segment at a time, called "Non-RL (Seq)" From Tab. 3, both "Non-RL (All)" and "Non-RL (Seq)" decrease MS-TCN's performance. More details on "Non-RL" are presented in the supplement. + +Policy. Tab. 4 compares MS-TCN performance on GTAE for our multi-agent formulation and an alternative single-agent feature augmentation. The latter does not learn frame masking, and hence does not have our agent 2. The single-agent, denoted as $\mu_1 / 10$ or $\mu_1 / 20$ , uses only policy $\mu_1$ for augmenting frame features. The values 10 and 20 indicate the percent of video randomly selected for augmentation at each policy iteration. Our multi-agent, denoted as $\mu_1 / \mu_2$ , uses both $\mu_1$ and $\mu_2$ policies. Tab. 4 shows that adding the second agent significantly improves the results. + +Improving transcripts variability. Generating new transcripts modify the total count of action transition initially present in the original set of transcripts. The advantage of our MCTS based generation approach is the emphasis on exploration. The number of poorly represented action transitions are increased with the new transcripts in training. Tab. 5 shows some example action transitions that are the least represented in the original training set get at least one new instance when adding the generated transcripts. + +# 6.2. Impact of MVGA on SOTA + +The top of Tab. 6 reports results of state-of-the-art (SOTA) fully supervised methods that do not use video augmentation in training (some of them use sophisticated post-processing, which we do not have). Tab. 6 also shows how MVGA affects performance of SOTA approaches – including: MS-TCN[11], BCN [40], ASFormer [43], and BridgePrompt [26] – on Breakfast, GTAE, and 50Salads. As can + +
DatasetBreakfastGTEA50Salads
MethodF1@10,25,50EditMoFF1@10,25,50EditMoFF1@10,25,50EditMoF
MSTCN++ [27]64.158.645.965.667.687.886.274.482.678.980.778.570.174.383.7
ASRF [18]74.368.956.172.467.689.487.879.883.777.384.983.577.379.384.5
HASR [1]74.769.557.071.969.489.287.274.884.576.986.685.778.581.083.9
SSTDA [7]75.069.155.273.770.290.089.178.086.279.883.081.573.875.883.2
G2L [13]74.969.055.273.370.789.987.375.884.678.580.378.069.873.482.2
UVAST [2]76.770.056.668.286.277.169.754.290.562.281.270.483.977.169.7
MSTCN [11]52.648.137.961.766.385.883.469.879.076.376.374.064.567.980.7
MSTCN (Ours)58.154.644.463.466.887.384.972.482.078.075.873.866.868.282.7
MSTCN + MVGA68.966.155.868.171.190.988.879.288.279.680.177.971.274.183.2
BCN [40]68.765.555.066.270.488.587.177.384.479.882.381.374.074.384.4
BCN + MVGA70.867.757.368.371.891.390.080.686.780.583.782.475.877.285.6
ASFormer [43]76.070.657.475.073.590.188.879.284.679.785.183.476.079.685.6
ASFormer + MVGA75.672.159.776.874.291.390.579.386.480.386.384.978.781.386.0
Bridge-Prompt [26]94.192.083.091.681.289.287.881.383.888.1
Bridge-Prompt + MVGA95.293.484.892.182.690.889.483.286.188.9
+ +Table 6. Impact of MVGA on SOTA methods on Breakfast, GTEA and 50Salads, and comparison with the other SOTA approaches that do not use data augmentation. + +
DatasetBreakfastGTEA50Salads
MethodF1@10,25,50EditMoFF1@10,25,50EditMoFF1@10,25,50EditMoF
MSTCN + C2F[34]58.255.047.862.966.586.283.578.178.876.577.374.265.567.380.8
MSTCN + Speed55.052.741.960.165.984.880.866.178.875.777.375.967.868.881.2
MSTCN + MVGA68.966.155.868.171.190.988.879.288.279.680.177.971.274.183.2
ASFormer + C2F [34]75.872.357.575.272.990.388.078.884.278.984.582.676.178.784.0
ASFormer + Speed75.269.156.974.871.989.387.277.785.278.584.482.975.177.285.1
ASFormer + MVGA75.672.159.776.874.291.390.579.386.480.386.384.978.781.386.0
+ +Table 7. Comparison of different data augmentation methods on Breakfast, GTEA and 50Salads. + +be seen, for all of the four SOTA approaches, data augmentation by MVGA consistently produces performance gains relative to their respective performance without data augmentation. For instance, MSTCN+MVGA outperforms both MSTCN [11] and its more advanced relative MSTCN++ [27] without data augmentation. MVGA also improves the original ASFormer [43] producing the new state of the art performance on Breakfast. Applying MVGA on the features provided by Bridge-Prompt [26] and following the same training procedure as for the ASFormer gives the method Bridge-Prompt+MVGA with the best results on GTAE and 50Salads. In Tab. 6, we could not report Bridge-Prompt+MVGA performance on Breakfast, since the Bridge-Prompt model for action segmentation on Breakfast is not publicly available, and our own training of Bridge-Prompt on Breakfast gave poor results. + +Video augmentation has been considered in the context of self-supervised learning (typically as a part of pretraining). However, a comparison with such methods is beyond our scope, because MVGA directly allows for the unified fully supervised training on a larger, augmented training dataset. In Tab. 7, we compare MVGA with some baseline video augmentation methods which also directly enable fully supervised learning, including Speed and C2F [34]. The former randomly selects certain action instances in each original training video, and performs "speeding-up" (i.e., frame subsampling) or "slowing-down" (i.e., frame upsampling with interpolation) of their temporal intervals, + +and thus doubles the original training set. C2F randomly selects certain time intervals in every original training video. Then, for each selected interval, C2F assigns the dominant ground-truth action class with the largest temporal support in that interval, and also replaces all frame features within the interval with their max-pooled feature. As can be seen in Tab. 7, MVGA provides for better data augmentation for MS-TCN and ASFormer than Speed and C2F. + +# 7. Conclusion + +We have specified video data augmentation for action segmentation within the reinforcement learning framework. Our approach generates new action transcripts and their corresponding new videos, as well as modifies the feature embedding of video frames. The transcript generation uses the efficient Monte-Carlo Tree Search to produce new, legal, high-likelihood action sequences. Optimal amount and temporal locations of feature changes in the video are learned with a two-agent actor-critic network. Our video augmentation in training of representative, state-of-the-art, convolutional and transformer-based action segmenters leads to their significant performance gains on the benchmark Breakfast, GTEA, and 50salads datasets, in comparison to their original training without video augmentation. + +Acknowledgments This work was supported in part by DARPA MCS Award N66001-19-2-4035. + +# References + +[1] Hyemin Ahn and Dongheui Lee. Refining action segmentation with hierarchical video representations. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 16302-16310, 2021. +[2] Nadine Behrmann, S Alireza Golestaneh, Zico Kolter, Juergen Gall, and Mehdi Noroozi. Unified fully and timestamp supervised temporal action segmentation via sequence to sequence translation. arXiv preprint arXiv:2209.00638, 2022. +[3] Miriam Bellver Bueno, Xavier Giro-i Nieto, Ferran Marqués, and Jordi Torres. Hierarchical object detection with deep reinforcement learning. Deep Learning for Image Processing Applications, 31(164):3, 2017. +[4] Juan C Caicedo and Svetlana Lazebnik. Active object localization with deep reinforcement learning. In Proceedings of the IEEE international conference on computer vision, pages 2488-2496, 2015. +[5] Joao Carreira and Andrew Zisserman. Quo vadis, action recognition? a new model and the kinetics dataset. In CVPR, 2017. +[6] Boyu Chen, Dong Wang, Peixia Li, Shuang Wang, and Huchuan Lu. Real-time actor-critic tracking. In Proceedings of the European conference on computer vision (ECCV), pages 318-334, 2018. +[7] Min-Hung Chen, Baopu Li, Yingze Bao, Ghassan Al-Regib, and Zsolt Kira. Action segmentation with joint self-supervised temporal domain adaptation. In CVPR, 2020. +[8] César Roberto de Souza, Adrien Gaidon, Yohann Cabon, Naila Murray, and Antonio Manuel López. Generating human action videos by coupling 3d game engines and probabilistic graphical models. International Journal of Computer Vision, 128(5):1505-1536, 2020. +[9] César Roberto de Souza12, Adrien Gaidon, Yohann Cabon, and Antonio Manuel López. Procedural generation of videos to train deep action recognition networks. 2017. +[10] Li Ding and Chenliang Xu. Weakly-supervised action segmentation with iterative soft boundary assignment. In CVPR, June 2018. +[11] Yazan Abu Farha and Jurgen Gall. MS-TCN: Multi-stage temporal convolutional network for action segmentation. In CVPR, 2019. +[12] Alireza Fathi, Xiaofeng Ren, and James M Rehg. Learning to recognize objects in egocentric activities. In CVPR 2011, pages 3281-3288. IEEE, 2011. +[13] Shang-Hua Gao, Qi Han, Zhong-Yu Li, Pai Peng, Liang Wang, and Ming-Ming Cheng. Global2local: Efficient structure search for video action segmentation. In CVPR, 2021. +[14] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. Communications of the ACM, 63(11):139-144, 2020. +[15] Junling Hu and Michael P Wellman. Nash q-learning for general-sum stochastic games. Journal of machine learning research, 4(Nov):1039-1069, 2003. +[16] Chen Huang, Simon Lucey, and Deva Ramanan. Learning policies for adaptive tracking with deep feature cascades. In + +Proceedings of the IEEE international conference on computer vision, pages 105-114, 2017. +[17] Shariq Iqbal and Fei Sha. Actor-attention-critic for multiagent reinforcement learning. In International conference on machine learning, pages 2961–2970. PMLR, 2019. +[18] Yuchi Ishikawa, Seito Kasai, Yoshimitsu Aoki, and Hirokatsu Kataoka. Alleviating over-segmentation errors by detecting action boundaries. In WACV, 2021. +[19] Takashi Isobe, Jian Han, Fang Zhuz, Yali Liy, and Shengjin Wang. Intra-clip aggregation for video person re-identification. In 2020 IEEE International Conference on Image Processing (ICIP), pages 2336-2340. IEEE, 2020. +[20] Levente Kocsis and Csaba Szepesvári. Bandit based montecarlo planning. In European conference on machine learning, pages 282-293. Springer, 2006. +[21] Vijay Konda and John Tsitsiklis. Actor-critic algorithms. Advances in neural information processing systems, 12, 1999. +[22] Hilde Kuehne, Ali Arslan, and Thomas Serre. The language of actions: Recovering the syntax and semantics of goal-directed human activities. In CVPR, 2014. +[23] Colin Lea, Michael D. Flynn, Rene Vidal, Austin Reiter, and Gregory D. Hager. Temporal convolutional networks for action segmentation and detection. In CVPR, 2017. +[24] Peng Lei and Sinisa Todorovic. Temporal deformable residual networks for action segmentation in videos. In CVPR, 2018. +[25] Jie Li, Mingqiang Yang, Yupeng Liu, Yanyan Wang, Qinghe Zheng, and Deqiang Wang. Dynamic hand gesture recognition using multi-direction 3d convolutional neural networks. Engineering Letters, 27(3), 2019. +[26] Muheng Li, Lei Chen, Yueqi Duan, Zhilan Hu, Jianjiang Feng, Jie Zhou, and Jiwen Lu. Bridge-prompt: Towards ordinal action understanding in instructional videos. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 19880-19889, 2022. +[27] Shi-Jie Li, Yazan AbuFarha, Yun Liu, Ming-Ming Cheng, and Juergen Gall. MS-TCN++: Multi-stage temporal convolutional network for action segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020. +[28] Xuan Liao, Wenhao Li, Qisen Xu, Xiangfeng Wang, Bo Jin, Xiaoyun Zhang, Yanfeng Wang, and Ya Zhang. Iteratively-refined interactive 3d medical image segmentation with multi-agent reinforcement learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 9394-9402, 2020. +[29] Shiqi Lin, Tao Yu, Ruoyu Feng, Xin Li, Xin Jin, and Zhibo Chen. Local patch autoaugment with multi-agent collaboration. arXiv preprint arXiv:2103.11099, 2021. +[30] Michael L Littman et al. Friend-or-foe q-learning in general-sum games. In ICML, volume 1, pages 322–328, 2001. +[31] Ze Liu, Jia Ning, Yue Cao, Yixuan Wei, Zheng Zhang, Stephen Lin, and Han Hu. Video swim transformer. arXiv preprint arXiv:2106.13230, 2021. +[32] Chaofan Ma, Qisen Xu, Xiangfeng Wang, Bo Jin, Xiaoyun Zhang, Yanfeng Wang, and Ya Zhang. Boundary-aware supervoxel-level iteratively refined interactive 3d image segmentation with multi-agent reinforcement learning. IEEE Transactions on Medical Imaging, 40(10):2563-2574, 2020. + +[33] Naima Otberdout, Mohammed Daoudi, Anis Kacem, Lahoucine Ballihi, and Stefano Berretti. Dynamic facial expression generation on hilbert hypersphere with conditional Wasserstein generative adversarial nets. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020. +[34] Dipika Singhania, Rahul Rahaman, and Angela Yao. Coarse to fine multi-resolution temporal convolutional network. In CVPR, 2021. +[35] Li Siyao, Weijiang Yu, Tianpei Gu, Chunze Lin, Quan Wang, Chen Qian, Chen Change Loy, and Ziwei Liu. Bailando: 3d dance generation by actor-critic gpt with choreographic memory. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11050-11059, 2022. +[36] Sebastian Stein and Stephen J McKenna. Combining embedded accelerometers with computer vision for recognizing food preparation activities. In Proceedings of the 2013 ACM international joint conference on Pervasive and ubiquitous computing, pages 729-738, 2013. +[37] Richard S Sutton and Andrew G Barto. Reinforcement learning: An introduction. MIT press, 2018. +[38] Liangliang Wang, Lianzheng Ge, Ruifeng Li, and Yajun Fang. Three-stream cnns for action recognition. Pattern Recognition Letters, 92:33-40, 2017. +[39] Yuqing Wang, Zhaoliang Xu, Xinlong Wang, Chunhua Shen, Baoshan Cheng, Hao Shen, and Huaxia Xia. End-to-end video instance segmentation with transformers. In CVPR, 2021. +[40] Zhenzhi Wang, Ziteng Gao, Limin Wang, Zhifeng Li, and Gangshan Wu. Boundary-aware cascade networks for temporal action segmentation. In ECCV, 2020. +[41] Dongxu Wei, Xiaowei Xu, Haibin Shen, and Kejie Huang. Gac-gan: A general method for appearance-controllable human video motion transfer. IEEE Transactions on Multimedia, 23:2457-2470, 2020. +[42] Di Wu, Junjun Chen, Nabin Sharma, Shirui Pan, Guodong Long, and Michael Blumenstein. Adversarial action data augmentation for similar gesture action recognition. In 2019 International Joint Conference on Neural Networks (IJCNN), pages 1-8. IEEE, 2019. +[43] Fangqiu Yi, Hongyu Wen, and Tingting Jiang. AS-Former: Transformer for action segmentation. CoRR, arXiv 2110.08568, 2021. \ No newline at end of file diff --git a/2023/Markov Game Video Augmentation for Action Segmentation/images.zip b/2023/Markov Game Video Augmentation for Action Segmentation/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..9a9b448fd655003c20cc682f71725033f8812b95 --- /dev/null +++ b/2023/Markov Game Video Augmentation for Action Segmentation/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:085e246e56fab6a9cfc2af7f60e9fc2ace79b9394d43a980d3da40217e3a4f9b +size 550392 diff --git a/2023/Markov Game Video Augmentation for Action Segmentation/layout.json b/2023/Markov Game Video Augmentation for Action Segmentation/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..74c4f01325a00179f0fcb8b08b691f654b605da2 --- /dev/null +++ b/2023/Markov Game Video Augmentation for Action Segmentation/layout.json @@ -0,0 +1,9920 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 110, + 103, + 484, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 103, + 484, + 121 + ], + "spans": [ + { + "bbox": [ + 110, + 103, + 484, + 121 + ], + "type": "text", + "content": "Markov Game Video Augmentation for Action Segmentation" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 179, + 144, + 254, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 179, + 144, + 254, + 156 + ], + "spans": [ + { + "bbox": [ + 179, + 144, + 254, + 156 + ], + "type": "text", + "content": "Nicolas Aziere" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 157, + 158, + 276, + 172 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 157, + 158, + 276, + 172 + ], + "spans": [ + { + "bbox": [ + 157, + 158, + 276, + 172 + ], + "type": "text", + "content": "Oregon State University" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 154, + 174, + 280, + 184 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 154, + 174, + 280, + 184 + ], + "spans": [ + { + "bbox": [ + 154, + 174, + 280, + 184 + ], + "type": "text", + "content": "azieren@oregonstate.edu" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 337, + 144, + 421, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 337, + 144, + 421, + 156 + ], + "spans": [ + { + "bbox": [ + 337, + 144, + 421, + 156 + ], + "type": "text", + "content": "Sinisa Todorovic" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 320, + 158, + 437, + 172 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 320, + 158, + 437, + 172 + ], + "spans": [ + { + "bbox": [ + 320, + 158, + 437, + 172 + ], + "type": "text", + "content": "Oregon State University" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 319, + 174, + 440, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 319, + 174, + 440, + 185 + ], + "spans": [ + { + "bbox": [ + 319, + 174, + 440, + 185 + ], + "type": "text", + "content": "sinisa@oregonstate.edu" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "spans": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 239, + 289, + 501 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 239, + 289, + 501 + ], + "spans": [ + { + "bbox": [ + 46, + 239, + 289, + 501 + ], + "type": "text", + "content": "This paper addresses data augmentation for action segmentation. Our key novelty is that we augment the original training videos in the deep feature space, not in the visual spatiotemporal domain as done by previous work. For augmentation, we modify original deep features of video frames such that the resulting embeddings fall closer to the class decision boundaries. Also, we edit action sequences of the original training videos (a.k.a. transcripts) by inserting, deleting, and replacing actions such that the resulting transcripts are close in edit distance to the ground-truth ones. For our data augmentation we resort to reinforcement learning, instead of more common supervised learning, since we do not have access to reliable oracles which would provide supervision about the optimal data modifications in the deep feature space. For modifying frame embeddings, we use a meta-model formulated as a Markov Game with multiple self-interested agents. Also, new transcripts are generated using a fast, parameter-free Monte Carlo tree search. Our experiments show that the proposed data augmentation of the Breakfast, GTEA, and 50Salads datasets leads to significant performance gains of several state of the art action segmenters." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 525, + 128, + 538 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 525, + 128, + 538 + ], + "spans": [ + { + "bbox": [ + 47, + 525, + 128, + 538 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 545, + 287, + 701 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 545, + 287, + 701 + ], + "spans": [ + { + "bbox": [ + 46, + 545, + 287, + 701 + ], + "type": "text", + "content": "This paper presents a new data augmentation framework for fully supervised action segmentation of untrimmed videos. Action segmentation is a basic vision problem. Despite recent tremendous advances in terms of new action segmenters and learning strategies, there is relatively slow progress in increasing the size of existing benchmark datasets. In comparison with peer datasets for action recognition or image classification, available benchmarks for action segmentation are significantly smaller. This presents challenges in training of recent action segmenters which show tendency to overfit on small datasets [11, 43, 40]. However, compiling large datasets is difficult, due to, in part, high costs of manual annotation of action segments." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 59, + 702, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 702, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 59, + 702, + 287, + 714 + ], + "type": "text", + "content": "We propose to augment existing datasets with newly gen" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 213, + 545, + 286 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 213, + 545, + 286 + ], + "spans": [ + { + "bbox": [ + 304, + 213, + 545, + 286 + ], + "type": "text", + "content": "erated video sequences, such that the resulting data augmentation enables more robust training and hence improves performance of action segmenters. Our approach is agnostic of a particular model for action segmentation, and expects that the segmenter has been pre-trained on the original training dataset to predict action classes of video frames." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 289, + 546, + 409 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 289, + 546, + 409 + ], + "spans": [ + { + "bbox": [ + 304, + 289, + 546, + 409 + ], + "type": "text", + "content": "Augmentation of video data has been mostly considered in the spatiotemporal, visual domain [38, 25, 19], where a human expert would heuristically specify the amount and type of data manipulation (e.g., subsampling, cropping, flipping of video frames) that are useful in training. While these approaches show great success, it is hard to formalize them in a principled manner. Others learn to generate new videos [9, 8, 42, 41], but the results are not sufficiently realistic yet, and hence would require domain adaptation if used for data augmentation in action segmentation." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 411, + 547, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 411, + 547, + 651 + ], + "spans": [ + { + "bbox": [ + 304, + 411, + 547, + 651 + ], + "type": "text", + "content": "Our key novelty is that we augment the original training videos directly in the deep feature space, unlike most previous work. As shown in Fig. 1 (top left), for augmentation, we modify original deep features of video frames at the input, such that the resulting embeddings fall closer to the class decision boundaries. Thus, by construction, we enforce that the augmented features be more challenging for learning, and in this way subsequently enable more robust training of the action segmenter. In addition, Fig. 1 (top right) illustrates that we also edit action sequences of the original training videos (a.k.a. transcripts) by inserting, deleting, and replacing actions, such that the resulting transcripts are close in edit distance to the groundtruth ones. Since the generated transcripts are kept similar to the originals, they are expected to be meaningful (i.e., legal) and provide a greater variety of legal action sequences than seen in the original training set. This is especially important for those application domains where some transcripts of interest are naturally rare and hence underrepresented in the original training dataset." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 653, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 547, + 715 + ], + "type": "text", + "content": "For the proposed augmentation of frame embeddings in the deep feature space, we specify a deep residual metamodel, as shown in Fig. 1 (bottom left). The meta-model takes deep features of frames at the input and predicts an optimal amount of feature modifications - i.e., offset fea" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 493, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 493, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 493, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 294, + 748, + 317, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 758 + ], + "type": "text", + "content": "13505" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 72, + 286, + 199 + ], + "blocks": [ + { + "bbox": [ + 50, + 72, + 286, + 199 + ], + "lines": [ + { + "bbox": [ + 50, + 72, + 286, + 199 + ], + "spans": [ + { + "bbox": [ + 50, + 72, + 286, + 199 + ], + "type": "image", + "image_path": "07e320007427c9b028287eb228d18bdca74202a43981638ece08e9a5d1256c40.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 213, + 287, + 344 + ], + "lines": [ + { + "bbox": [ + 46, + 213, + 287, + 344 + ], + "spans": [ + { + "bbox": [ + 46, + 213, + 287, + 344 + ], + "type": "text", + "content": "Figure 1. The proposed two-pronged data augmentation: (top and bottom left) Original deep features of frames at the input of a meta-model are modified to fall closer to class decision boundaries of the pretrained action segmenter. Alternative frameworks are considered for training the meta-model, including Gaussian noise, or supervised learning of a Temporal CNN, or reinforcement learning of an Actor-Critic network. (top and bottom right) The original action transcripts of training videos are modified by inserting, replacing, and removing actions, while ensuring a small edit distance between the newly generated transcripts and the originals. For training the meta-model for transcript augmentation, we consider supervised learning and alternatively a Monte Carlo tree search." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 354, + 286, + 413 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 354, + 286, + 413 + ], + "spans": [ + { + "bbox": [ + 46, + 354, + 286, + 413 + ], + "type": "text", + "content": "tures which are added to the original frame features, resulting in augmented embeddings. For training the meta-model, we consider both RL (Fig. 1 (bottom left)) and supervised learning. From our experiments, RL proves to be a more reliable paradigm." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 414, + 286, + 557 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 414, + 286, + 557 + ], + "spans": [ + { + "bbox": [ + 46, + 414, + 286, + 557 + ], + "type": "text", + "content": "Supervised learning of the proposed meta-model faces a fundamental challenge. As a direct consequence of performing data augmentation in the deep feature space, there is no reliable oracle which would provide supervision for the optimal amount of feature modifications. The only available oracle is the pre-trained action segmentation model which could predict action labels of the augmented frame embeddings, and the incurred loss could be used for training the meta-model. The action segmentation model provides only pseudo-labels for generated data – not ground-truth labels – and hence a fully-supervised training of our meta-model could suffer from noisy pseudo-labels." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 558, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 558, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 558, + 286, + 713 + ], + "type": "text", + "content": "An alternative is to resort to reinforcement learning (RL) due to the following advantages. First, it allows us to sequentially modify frame features, where previous modifications define a state in which RL estimates an optimal modification of the next frames. Learning of the proposed sequential feature augmentation is expected to be more reliable, especially for long video sequences, than learning how to optimally modify all frame embeddings at once. RL produces an optimal policy which would account for temporal dependence between frame embeddings, and hence make them suitable for action segmentation models with large temporal receptive fields (like MS-TCN or AS-Former). Second, RL is expected to provide for a more sta" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 72, + 545, + 215 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 215 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 215 + ], + "type": "text", + "content": "ble training of our meta-model by optimizing the expected reward over a policy of feature modifications, in comparison with the aforementioned minimization of the unreliable loss of the pretrained action segmenter on particular feature modifications. Third, RL is known to be very effective for problems with a large, continuous, output space, as is our case of predicting offset features in the deep feature space. Finally, RL is known to successfully address non-stationary environments with the distribution shift between training and test sets [37], which exactly characterizes our problem statement where data augmentation is aimed at bridging the distribution shift." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 216, + 545, + 299 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 216, + 545, + 299 + ], + "spans": [ + { + "bbox": [ + 304, + 216, + 545, + 299 + ], + "type": "text", + "content": "Within the RL framework, for modifying frame embeddings, we formulate the meta-model as a Deep Actor-Critic Network for learning policies of two self-interested agents in a Markov Game. Also, for generating new transcripts, we use a fast, parameter-free Monte Carlo tree search. We call our approach Markov Game Video Augmentation (MVGA)." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 300, + 545, + 383 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 300, + 545, + 383 + ], + "spans": [ + { + "bbox": [ + 304, + 300, + 545, + 383 + ], + "type": "text", + "content": "Our experimental evaluation shows significant performance gains of recent convolutional and transformer-based action segmenters when our MVGA is used to augment the Breakfast, GTEA, and 50Salads datasets. Interestingly, MVGA enables the convolutional model MS-TCN [11, 27] achieve close performance to that of the significantly more complex (and more recent) ASFormer [43]." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 383, + 545, + 431 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 383, + 545, + 431 + ], + "spans": [ + { + "bbox": [ + 304, + 383, + 545, + 431 + ], + "type": "text", + "content": "In the following, Sec. 2 reviews closely related work, Sec. 3 gives an overview of MVGA, Sec. 4 specifies our transcript augmentation, Sec. 5 formalizes our frame-feature augmentation, and Sec. 6 presents our results." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 442, + 392, + 454 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 442, + 392, + 454 + ], + "spans": [ + { + "bbox": [ + 306, + 442, + 392, + 454 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 462, + 544, + 486 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 462, + 544, + 486 + ], + "spans": [ + { + "bbox": [ + 304, + 462, + 544, + 486 + ], + "type": "text", + "content": "This section reviews closely related work on fully supervised action segmentation and video data augmentation." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 486, + 545, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 486, + 545, + 653 + ], + "spans": [ + { + "bbox": [ + 304, + 486, + 545, + 653 + ], + "type": "text", + "content": "A family of temporal convolution models [10, 23, 24, 11, 40, 27, 34] have been studied for action segmentation. Some of these models use gradual temporal pooling for overcoming oversegmentation [10, 23, 24, 34], and others integrate reasoning about action boundaries [40, 18]. As representatives of this family, in our experiments, we consider MS-TCN [11, 27] and boundary-aware BCN [40] both of which consist of multiple stages of temporal convolution layers. Recent transformer-based models [43, 31, 39, 2] outperform temporal convolution models. Among these transformers, for evaluation, we consider ASFormer [43]. Both MS-TCN and ASFormer use standard I3D deep features [5]) of video frames as input. We also study a version of ASFormer with more informative frame embeddings [26]." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": "Video augmentation in the visible space-time domain, such as, e.g., temporal cropping of frames [38, 25] or random cropping/removing/flipping of frames in a training mini-batch [19] have become standard practice in action recognition, person re-ID, and hand gesture recogni" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "13506" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 286, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 286, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 286, + 156 + ], + "type": "text", + "content": "tion. Other data augmentation methods have also been used, including pooling frame features within a window of variable length [34]. For video augmentation, some approaches generate simulated videos with video-game engines [9, 8], or GANs [14, 42, 41, 33]. However, there is still a large domain gap between such simulated and real videos, which limits the utility of these methods for data augmentation." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 156, + 286, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 156, + 286, + 228 + ], + "spans": [ + { + "bbox": [ + 46, + 156, + 286, + 228 + ], + "type": "text", + "content": "Reinforcement learning has been used for addressing various vision problems, including 3D image segmentation [28, 32], image classification [29], object detection [3, 4], and tracking [6, 16]. To the best of our knowledge, video data augmentation for action segmentation has never been formulated within the reinforcement learning framework." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 240, + 164, + 252 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 240, + 164, + 252 + ], + "spans": [ + { + "bbox": [ + 47, + 240, + 164, + 252 + ], + "type": "text", + "content": "3. Overview of MVGA" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "spans": [ + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "content": "In this and following two sections, we focus on our reinforcement learning formulation of the proposed data augmentation. The supervised learning formulation is described in Sec. 6. Fig. 2 shows an overview of our approach which consists of the following four steps. The first step pre-trains an action segmenter on a given training dataset " + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "content": ". A training video of length " + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "content": " in " + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "content": " is given by its deep features for every frame " + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "inline_equation", + "content": "\\mathcal{X} = \\{x_t : t = 1, \\dots, T\\}" + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "inline_equation", + "content": "x_t \\in \\mathbb{R}^{d_{\\mathrm{in}}}" + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "content": " (" + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "inline_equation", + "content": "d_{\\mathrm{in}} = 2048" + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "content": " for standard I3D features [5]), and the ground-truth action classes " + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "inline_equation", + "content": "\\mathcal{Y} = \\{y_t : t = 1, \\dots, T\\}" + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "inline_equation", + "content": "y_t \\in \\mathbb{Y}" + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "inline_equation", + "content": "\\mathbb{Y}" + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "content": " is a set of action classes. After pretraining, the action segmenter " + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "inline_equation", + "content": "f_{\\theta}" + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "content": " can be used to predict action classes of video frames " + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "inline_equation", + "content": "\\hat{\\mathcal{Y}} = f(\\mathcal{X}; \\theta)" + }, + { + "bbox": [ + 46, + 261, + 286, + 416 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 417, + 286, + 511 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 417, + 286, + 511 + ], + "spans": [ + { + "bbox": [ + 46, + 417, + 286, + 511 + ], + "type": "text", + "content": "The second step generates new transcripts and their corresponding videos. We use the UCT algorithm [20] to first efficiently construct a tree, whose paths from the root to leaves represent legal transcripts, and then select optimal paths. For every new transcript, a new video is constructed by copying appropriate action segments from real videos in " + }, + { + "bbox": [ + 46, + 417, + 286, + 511 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 46, + 417, + 286, + 511 + ], + "type": "text", + "content": " to the new video following the action sequence of the new transcript." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 513, + 286, + 584 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 513, + 286, + 584 + ], + "spans": [ + { + "bbox": [ + 46, + 513, + 286, + 584 + ], + "type": "text", + "content": "The third step augments features of the original and new videos with the Actor and Critic networks, which gives the augmented dataset " + }, + { + "bbox": [ + 46, + 513, + 286, + 584 + ], + "type": "inline_equation", + "content": "\\mathcal{D}'" + }, + { + "bbox": [ + 46, + 513, + 286, + 584 + ], + "type": "text", + "content": ". The Actor predicts how much and where to modify features in the input video. The Critic estimates the expected rewards for the Actor. Both Actor and Critic are learned using the pre-trained " + }, + { + "bbox": [ + 46, + 513, + 286, + 584 + ], + "type": "inline_equation", + "content": "f_{\\theta}" + }, + { + "bbox": [ + 46, + 513, + 286, + 584 + ], + "type": "text", + "content": " as oracle." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 585, + 286, + 608 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 585, + 286, + 608 + ], + "spans": [ + { + "bbox": [ + 46, + 585, + 286, + 608 + ], + "type": "text", + "content": "The fourth step fine-tunes " + }, + { + "bbox": [ + 46, + 585, + 286, + 608 + ], + "type": "inline_equation", + "content": "f_{\\theta}" + }, + { + "bbox": [ + 46, + 585, + 286, + 608 + ], + "type": "text", + "content": " such that every mini-batch consists of videos from both " + }, + { + "bbox": [ + 46, + 585, + 286, + 608 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 46, + 585, + 286, + 608 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 585, + 286, + 608 + ], + "type": "inline_equation", + "content": "\\mathcal{D}'" + }, + { + "bbox": [ + 46, + 585, + 286, + 608 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 59, + 609, + 282, + 621 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 609, + 282, + 621 + ], + "spans": [ + { + "bbox": [ + 59, + 609, + 282, + 621 + ], + "type": "text", + "content": "In the following, we specify the second and third steps." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 633, + 258, + 646 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 633, + 258, + 646 + ], + "spans": [ + { + "bbox": [ + 47, + 633, + 258, + 646 + ], + "type": "text", + "content": "4. New Transcript and Video Generation" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 654, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 654, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 654, + 286, + 713 + ], + "type": "text", + "content": "From " + }, + { + "bbox": [ + 46, + 654, + 286, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 46, + 654, + 286, + 713 + ], + "type": "text", + "content": ", we generate new transcripts and their corresponding new videos. The new transcripts should be semantically meaningful, i.e., legal. This is enforced by requiring that the new transcripts have: (i) similar lengths as the original transcripts; and (ii) high likelihoods of consec" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 72, + 545, + 192 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 192 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 192 + ], + "type": "text", + "content": "utive pairs of action classes. Our experiments suggest that auto-regressive models - e.g., a recurrent-neural network (RNN) or Transformer network [35] - provide poor transcript generation, since they require large training datasets and hence have limited utility for our target settings where data augmentation is needed to address lack of data. Therefore, in this section, we focus on an alternative framework - parameter-free Monte-Carlo Tree Search (MTCS), where the space of transcripts is efficiently represented by a tree. We first construct the tree, and then identify its optimal path." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 200, + 508, + 213 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 200, + 508, + 213 + ], + "spans": [ + { + "bbox": [ + 305, + 200, + 508, + 213 + ], + "type": "text", + "content": "4.1. MTCS for New Transcript Generation" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "spans": [ + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "text", + "content": "In the tree of transcripts, the root represents the dummy \"start\" of action sequences. The root's descendants sequentially add action classes to the transcripts until leaf nodes, which represent the dummy \"end\". A node " + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "inline_equation", + "content": "v" + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "text", + "content": " represents the last action class of the path " + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "inline_equation", + "content": "\\pi_v" + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "text", + "content": " from the root to " + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "inline_equation", + "content": "v" + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "inline_equation", + "content": "\\pi_v = \\{\\text{\"start\", } y_1, \\dots, y_v}\\}" + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "inline_equation", + "content": "y_v \\in \\mathbb{Y}" + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "inline_equation", + "content": "y_v = \\text{\"end\"}" + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "text", + "content": " if " + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "inline_equation", + "content": "v" + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "text", + "content": " is a leaf node. Each node is assigned a weight, " + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "inline_equation", + "content": "w(v)" + }, + { + "bbox": [ + 304, + 219, + 545, + 315 + ], + "type": "text", + "content": ", specified as the joint likelihood of the corresponding path:" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 353, + 324, + 545, + 352 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 353, + 324, + 545, + 352 + ], + "spans": [ + { + "bbox": [ + 353, + 324, + 545, + 352 + ], + "type": "interline_equation", + "content": "w (v) = p \\left(\\left| \\pi_ {v} \\right|\\right) \\prod_ {\\left(u, u ^ {\\prime}\\right) \\in \\pi_ {v}} p \\left(y _ {u ^ {\\prime}} \\mid y _ {u}\\right), \\tag {1}", + "image_path": "6de4ad8d11b01339af3cf6933faee2b295bbeec79dd43d4d02353c231617d939.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "spans": [ + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "p(|\\pi_v|)" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": " is a prior of the transcript length, " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "u'" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": " is a child of " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "u" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": " along " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "\\pi_v" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "p(y_{u'} | y_u)" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": " denotes the transition probability of consecutive actions. In the special case, " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "p(y_{u'} | \"start\")" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "p(\"end\" | y_u)" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": " represent the priors that the transcript begins and ends with classes " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "y_{u'}, y_u \\in \\mathbb{Y}" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": ". Both " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "p(|\\pi_v|)" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "p(y_{u'} | y_u)" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": " are estimated from " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": ". For " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "p(|\\pi_v|)" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": " we learn the Poisson distribution, and for " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "p(y_{u'} | y_u)" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": " we estimate the frequency of the corresponding class transitions in " + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 304, + 361, + 545, + 456 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 457, + 545, + 578 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 457, + 545, + 578 + ], + "spans": [ + { + "bbox": [ + 304, + 457, + 545, + 578 + ], + "type": "text", + "content": "The tree is constructed iteratively using the well-known UCT algorithm [20] which balances a trade-off between exploitation and exploration. In each iteration, the root is sequentially expanded with a path of optimal descendants until the dummy \"end\" leaf or the maximum tree depth is reached. We do not allow illegal expansions, i.e., a path is guaranteed to consist of class transitions seen in " + }, + { + "bbox": [ + 304, + 457, + 545, + 578 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 304, + 457, + 545, + 578 + ], + "type": "text", + "content": ". Suppose a path has reached node " + }, + { + "bbox": [ + 304, + 457, + 545, + 578 + ], + "type": "inline_equation", + "content": "u" + }, + { + "bbox": [ + 304, + 457, + 545, + 578 + ], + "type": "text", + "content": " without meeting the stopping criterion. Then, UCT adds to the path the optimal node " + }, + { + "bbox": [ + 304, + 457, + 545, + 578 + ], + "type": "inline_equation", + "content": "u'" + }, + { + "bbox": [ + 304, + 457, + 545, + 578 + ], + "type": "text", + "content": " from a subset of children, " + }, + { + "bbox": [ + 304, + 457, + 545, + 578 + ], + "type": "inline_equation", + "content": "\\mathrm{ch}(u) \\subset \\mathrm{Ch}(u) = \\{u': p(y_{u'} | y_u) > 0\\}" + }, + { + "bbox": [ + 304, + 457, + 545, + 578 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 341, + 586, + 545, + 619 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 341, + 586, + 545, + 619 + ], + "spans": [ + { + "bbox": [ + 341, + 586, + 545, + 619 + ], + "type": "interline_equation", + "content": "u ^ {\\prime} = \\arg \\max _ {v \\in \\operatorname {c h} (u)} \\left[ w (v) + c \\sqrt {\\frac {2 \\log n (u)}{n (v)}} \\right] \\tag {2}", + "image_path": "f5e65b150f7ea7112c9c153c2dd84b22e552fbdb0a0296a62b53171edceca7a6.jpg" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\operatorname{ch}(u)" + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "text", + "content": " is randomly sampled " + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "text", + "content": " of " + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\operatorname{Ch}(u)" + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "text", + "content": " to enable exploring alternative paths; " + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "inline_equation", + "content": "w(v)" + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "text", + "content": " is given by (1); " + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "inline_equation", + "content": "c = \\frac{1}{\\sqrt{2}}" + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "text", + "content": " is the exploration-exploitation trade-off parameter; and " + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "inline_equation", + "content": "n(v)" + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "text", + "content": " is the number of paths in the current tree that include node " + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "inline_equation", + "content": "v" + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "text", + "content": ". As the tree iteratively grows, the value of " + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "inline_equation", + "content": "n(v)" + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "text", + "content": " keeps changing for every node, which enables exploring less visited nodes in the space of transcripts even if " + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "inline_equation", + "content": "w(v)" + }, + { + "bbox": [ + 304, + 627, + 545, + 713 + ], + "type": "text", + "content": " is small." + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13507" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 100, + 70, + 496, + 268 + ], + "blocks": [ + { + "bbox": [ + 100, + 70, + 496, + 268 + ], + "lines": [ + { + "bbox": [ + 100, + 70, + 496, + 268 + ], + "spans": [ + { + "bbox": [ + 100, + 70, + 496, + 268 + ], + "type": "image", + "image_path": "a14584df1770b75c98816c93bbaa46f6a2becf24c61097e5214b864531491a21.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 273, + 547, + 340 + ], + "lines": [ + { + "bbox": [ + 46, + 273, + 547, + 340 + ], + "spans": [ + { + "bbox": [ + 46, + 273, + 547, + 340 + ], + "type": "text", + "content": "Figure 2. Our MVGA consists of four steps. 1-An action segmentation model is pre-trained using the original training set. 2-New transcripts are generated by selecting optimal paths in a UCT tree [20] of legal transcripts. For every new transcript, a new video is constructed by copying instances of action classes in the new transcript from real videos. 3- Features of the original and constructed new videos are augmented with the Actor and Critic networks. The Actor predicts the amount and location of feature modifications in the video. The Critic estimates the expected rewards for the Actor's two predictions. Both Actor and Critic are learned using the pre-trained action segmenter as oracle. 4- The action segmenter is fine-tuned on the original and augmented training videos." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 358, + 288, + 407 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 358, + 288, + 407 + ], + "spans": [ + { + "bbox": [ + 46, + 358, + 288, + 407 + ], + "type": "text", + "content": "After 1000 tree-growing iterations, the node " + }, + { + "bbox": [ + 46, + 358, + 288, + 407 + ], + "type": "inline_equation", + "content": "v^{*}" + }, + { + "bbox": [ + 46, + 358, + 288, + 407 + ], + "type": "text", + "content": " with the highest likelihood " + }, + { + "bbox": [ + 46, + 358, + 288, + 407 + ], + "type": "inline_equation", + "content": "v^{*} = \\arg \\max_{v} w(v)" + }, + { + "bbox": [ + 46, + 358, + 288, + 407 + ], + "type": "text", + "content": " in the tree uniquely identifies the newly generated transcript " + }, + { + "bbox": [ + 46, + 358, + 288, + 407 + ], + "type": "inline_equation", + "content": "\\pi_{v^{*}}" + }, + { + "bbox": [ + 46, + 358, + 288, + 407 + ], + "type": "text", + "content": ". For generating another transcript, we construct another tree anew." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 413, + 272, + 426 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 413, + 272, + 426 + ], + "spans": [ + { + "bbox": [ + 47, + 413, + 272, + 426 + ], + "type": "text", + "content": "4.2. Generating New Videos of New Transcripts" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "spans": [ + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": "Given a new transcript, " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\pi" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": ", we sequentially construct a new video with deep features (e.g., I3D [5]) following the ordering of action classes in " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\pi" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": ". It is worth emphasizing that our video generation occurs directly in the deep feature space. We begin by selecting a video " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_0 \\in \\mathcal{D}" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": " whose ground-truth transcript has the smallest edit distance to " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\pi" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": ". From " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_0" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": ", we remove all action segments that are not represented in " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\pi" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": ", resulting in our initial new video " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_0'" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": ". For action classes that are present in " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\pi" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": " but missing in " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_0'" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": ", we identify the second closest video " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_1 \\in \\mathcal{D}" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": " with these missing actions, and copy their respective temporal intervals to the appropriate locations in the new video, resulting in " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_1'" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": ". This is repeated until the entire " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\pi" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": " is fully represented by " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_g'" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "g = 0, 1, 2, \\ldots" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": ". Note that " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_g'" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": " keeps the original lengths of action instances found in real videos, which ensures temporal coherence of every action in " + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_g'" + }, + { + "bbox": [ + 46, + 432, + 288, + 636 + ], + "type": "text", + "content": ". A pseudo-code of the proposed video generation is given in the supplement." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 646, + 233, + 659 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 646, + 233, + 659 + ], + "spans": [ + { + "bbox": [ + 47, + 646, + 233, + 659 + ], + "type": "text", + "content": "5. Augmentation of Frame Features" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "content": "Features of both original and new videos are augmented by a Markov Game (MG) [15, 30, 37]. Since MG is a well-studied framework and we do not claim novelty in our particular formulation, below we rely that the reader is al-" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "spans": [ + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": "ready familiar with the motivation and main concepts of MG. Our MG consists of two agents which sequentially take independent actions causing state changes of a fully observable environment. The environment at step " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " is defined by state " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "s_k = (\\mathcal{X}_k, \\mathcal{M}_k)" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_k = \\{x_{k,t} : t = 1, \\dots, T\\}" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " is the set of current video frame features, and " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_k = \\{m_{k,t} : t = 1, \\dots, T\\}" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " is a binary mask assigned to the video frames, " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "m_{k,t} \\in \\{0,1\\}" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": ", for keeping the record which frames have been already modified. Given " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "s_k" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": ", the two agents follow their respective policies, " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "\\mu^1" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "\\mu^2" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": ", to take actions " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "a_k^1 = \\mu^1(s_k) \\in \\mathcal{A}^1" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "a_k^2 = \\mu^2(s_k) \\in \\mathcal{A}^2" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "\\mathcal{A}^1" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " is a continuous action space of agent 1, where " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "a_k^1 = \\{a_{t,k}^1 : t = 1, \\dots, T\\}" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " represents the amount of feature augmentation, i.e., offset features. " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "\\mathcal{A}^2" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " is a discrete action space of agent 2 for selecting video frames for augmentation, " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "a_k^2 \\in \\{0,1\\}^T" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "a_{t,k}^2 = 0" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " means that the frame " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " will not be augmented in step " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "a_k^1" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "a_k^2" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " cause the environment to change to next state " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "s_{k+1}" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": ", which incurs the respective two rewards " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "R_k^1 = R^1(s_k, s_{k+1}, f_\\theta)" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "R_k^2 = R^2(s_k, a_2^k)" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": ". Our goal is to learn " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "\\mu^1" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "inline_equation", + "content": "\\mu^2" + }, + { + "bbox": [ + 304, + 358, + 547, + 613 + ], + "type": "text", + "content": " so as to maximize the agents' action-value functions given by:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 315, + 624, + 545, + 662 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 624, + 545, + 662 + ], + "spans": [ + { + "bbox": [ + 315, + 624, + 545, + 662 + ], + "type": "interline_equation", + "content": "Q ^ {i} (s, a) = \\mathbb {E} \\left[ \\sum_ {k \\geq 0} (\\gamma) ^ {k} R _ {k} ^ {i} \\mid \\mu^ {i}, a _ {0} ^ {i} = a, s _ {0} = s \\right], i = \\{1, 2 \\} \\tag {3}", + "image_path": "95b9f3be2c5f199c0b6558ec9af9058f67501945be87ae3b9e7c4182e28145b0.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "spans": [ + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "type": "inline_equation", + "content": "\\mathbb{E}[\\cdot ]" + }, + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "type": "text", + "content": " denotes expected value, " + }, + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "type": "inline_equation", + "content": "\\gamma = 0.99" + }, + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "type": "text", + "content": " is the discount factor raised to the power of " + }, + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "type": "inline_equation", + "content": "s\\in S" + }, + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "type": "inline_equation", + "content": "a\\in \\mathcal{A}^i" + }, + { + "bbox": [ + 304, + 663, + 545, + 687 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 689, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 547, + 714 + ], + "type": "text", + "content": "For a given video, MG starts from the initial state " + }, + { + "bbox": [ + 306, + 689, + 547, + 714 + ], + "type": "inline_equation", + "content": "s_0 = (\\mathcal{X}_0, \\mathcal{M}_0)" + }, + { + "bbox": [ + 306, + 689, + 547, + 714 + ], + "type": "text", + "content": ", with the original frame features and all-zero" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13508" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "type": "text", + "content": "mask, " + }, + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_0 = \\mathcal{X}" + }, + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_0 = \\{0\\}^T" + }, + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "type": "text", + "content": ". In state " + }, + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "type": "inline_equation", + "content": "s_k" + }, + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "type": "text", + "content": ", the two agents take their respective actions, which gives " + }, + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "type": "inline_equation", + "content": "s_{k + 1}" + }, + { + "bbox": [ + 47, + 72, + 287, + 97 + ], + "type": "text", + "content": " specified as" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 67, + 104, + 286, + 118 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 104, + 286, + 118 + ], + "spans": [ + { + "bbox": [ + 67, + 104, + 286, + 118 + ], + "type": "interline_equation", + "content": "\\mathcal {X} _ {k + 1} = \\left\\{x _ {t, k} + a _ {t, k} ^ {2} \\left(a _ {t, k} ^ {1} + \\epsilon\\right): t = 1, \\dots , T \\right\\}, \\tag {4}", + "image_path": "bf8adc54e7d4b61af636a8deb2df0adfafe4707cb40898682e82a2cb0b559099.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 62, + 121, + 287, + 135 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 121, + 287, + 135 + ], + "spans": [ + { + "bbox": [ + 62, + 121, + 287, + 135 + ], + "type": "interline_equation", + "content": "\\mathcal {M} _ {k + 1} = \\mathcal {M} _ {k} \\vee a _ {k} ^ {2}, \\tag {5}", + "image_path": "50e07f936a8b75e8e90a729d7fb9d5864f27a88051ec8267e84a508040afad2a.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "spans": [ + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "inline_equation", + "content": "\\vee" + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "text", + "content": " is the logical OR operator, and " + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "inline_equation", + "content": "\\epsilon \\in \\mathbb{R}^{d_{\\mathrm{in}}}" + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "text", + "content": " is noise sampled from the zero-mean and unit-variance Gaussian distribution. " + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "text", + "content": " enables an exploration of " + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "inline_equation", + "content": "\\mathcal{A}^1" + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "text", + "content": " and provides a way to generate multiple, distinct, augmented features from the same initial state " + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "inline_equation", + "content": "s_0" + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "text", + "content": ". From (4), only frames selected by " + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "inline_equation", + "content": "a_k^2" + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "text", + "content": " get updated with the corresponding offset features " + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "inline_equation", + "content": "(a_k^1 + \\epsilon)" + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "text", + "content": ". Also, from (5), mask " + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_k" + }, + { + "bbox": [ + 47, + 142, + 287, + 239 + ], + "type": "text", + "content": " keeps the record of previously selected frames for augmentation." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 239, + 287, + 276 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 239, + 287, + 276 + ], + "spans": [ + { + "bbox": [ + 47, + 239, + 287, + 276 + ], + "type": "text", + "content": "MG stops as soon as one of the following happens (experimentally optimized): after " + }, + { + "bbox": [ + 47, + 239, + 287, + 276 + ], + "type": "inline_equation", + "content": "k = 10" + }, + { + "bbox": [ + 47, + 239, + 287, + 276 + ], + "type": "text", + "content": " steps, or when " + }, + { + "bbox": [ + 47, + 239, + 287, + 276 + ], + "type": "inline_equation", + "content": "95\\%" + }, + { + "bbox": [ + 47, + 239, + 287, + 276 + ], + "type": "text", + "content": " of the video has been augmented, " + }, + { + "bbox": [ + 47, + 239, + 287, + 276 + ], + "type": "inline_equation", + "content": "\\sum_{t=1}^{T} m_{t,k} \\geq 0.95T" + }, + { + "bbox": [ + 47, + 239, + 287, + 276 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 281, + 258, + 294 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 281, + 258, + 294 + ], + "spans": [ + { + "bbox": [ + 47, + 281, + 258, + 294 + ], + "type": "text", + "content": "5.1. Two Rewards for Feature Augmentation" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "spans": [ + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": "The policy of agent 1, " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\mu^1" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": ", is learned to augment original features, such that they become more challenging for the pre-trained action segmenter, " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "f_{\\theta}" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": ", and thus provide for a more robust subsequent training of " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "f_{\\theta}" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": " on the augmented training dataset. This is enforced by specifying the following reward " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "R_k^1 = R^1(s_k, s_{k+1}, f_{\\theta})" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": ". Let " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\hat{y}_t" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\hat{y}_t'" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": " denote the top two scoring class predictions for " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "x_{t,k}" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": " by " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "f_{\\theta}" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\hat{y}_t = \\arg \\max_{y \\in \\mathbb{Y}} p(y|x_{t,k};\\theta)" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\hat{y}_t' = \\arg \\max_{y \\in \\mathbb{Y} \\setminus \\{\\hat{y}_t\\}} p(y|x_{t,k};\\theta)" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": ". We penalize agent 1 with a negative reward whenever " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "a_k^1" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": " causes " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "f_{\\theta}" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": " to make a wrong prediction, " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\hat{y}_t \\neq y_t" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": ". We assign a positive reward to agent 1 when " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "f_{\\theta}" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": "'s prediction is equal to the ground truth, " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\hat{y}_t = y_t" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": ", and reduce this positive reward if the feature augmentation is not challenging enough for " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "f_{\\theta}" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": ". The positive reward reduction is proportional to " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "f_{\\theta}" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": "'s confidence in its prediction, specified as a difference between its top two scoring predictions, " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\kappa = [p(\\hat{y}_t|x_{t,k};\\theta) - p(\\hat{y}_t'|x_{j,k};\\theta)]" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "0 < \\kappa \\leq 1" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": ". Hence, when confidence " + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\kappa" + }, + { + "bbox": [ + 47, + 300, + 287, + 529 + ], + "type": "text", + "content": " is large and close to 1, the positive reward for agent 1 is maximally reduced as" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 83, + 539, + 225, + 570 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 83, + 539, + 225, + 570 + ], + "spans": [ + { + "bbox": [ + 83, + 539, + 225, + 570 + ], + "type": "interline_equation", + "content": "R _ {k} ^ {1} = \\frac {1}{\\| a _ {k} ^ {2} \\|} \\sum_ {t \\in \\mathcal {T} (a _ {k} ^ {2})} r ^ {1} (x _ {t, k + 1}, f _ {\\theta}),", + "image_path": "040beaf8fdff75c2be819a45a4051299b131d7e89b664bf80cf56ccc1045b4da.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 570, + 288, + 628 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 570, + 288, + 628 + ], + "spans": [ + { + "bbox": [ + 48, + 570, + 288, + 628 + ], + "type": "interline_equation", + "content": "r ^ {1} \\left(x _ {t, k}, f _ {\\theta}\\right) = \\left\\{ \\begin{array}{l l} 1 - \\left[ p \\left(\\hat {y} _ {t} \\mid x _ {t, k}; \\theta\\right) - p \\left(\\hat {y} _ {t} ^ {\\prime} \\mid x _ {t, k}; \\theta\\right) \\right], & \\text {i f} \\hat {y} _ {t} = y _ {t} \\\\ - 1 & , \\text {i f} \\hat {y} _ {t} \\neq y _ {t} \\end{array} \\right. \\tag {6}", + "image_path": "b52e955489f7507e24a1e6ea23ba99613aafae2ad6206363055afb241b992790.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 628, + 261, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 628, + 261, + 641 + ], + "spans": [ + { + "bbox": [ + 47, + 628, + 261, + 641 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 628, + 261, + 641 + ], + "type": "inline_equation", + "content": "\\mathcal{T}(a_k^2)" + }, + { + "bbox": [ + 47, + 628, + 261, + 641 + ], + "type": "text", + "content": " returns the set of frames where " + }, + { + "bbox": [ + 47, + 628, + 261, + 641 + ], + "type": "inline_equation", + "content": "a_{t,k}^2 = 1" + }, + { + "bbox": [ + 47, + 628, + 261, + 641 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "type": "text", + "content": "For the policy of agent 2, " + }, + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mu^2" + }, + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "type": "text", + "content": ", we specify the following three requirements: (i) " + }, + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mu^2" + }, + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "type": "text", + "content": " should not select frames which have already been augmented in the previous MG steps; (ii) frame selection should be local at each MG step and focus only on a very few action instances in the video (and in this way make learning of " + }, + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mu^1" + }, + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "type": "text", + "content": " easier); and (iii) selected temporal" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "content": "intervals should maximally overlap the ground-truth action instances. These three requirements are enforced by specifying the following reward:" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 309, + 117, + 545, + 182 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 117, + 545, + 182 + ], + "spans": [ + { + "bbox": [ + 309, + 117, + 545, + 182 + ], + "type": "interline_equation", + "content": "R _ {k} ^ {2} = \\left\\{ \\begin{array}{c} \\sum_ {\\tau} \\frac {| \\tau \\cap a _ {k} ^ {2} |}{| \\tau |}, \\text {i f} \\sum_ {t} a _ {t, k} ^ {2} m _ {t, k} < \\alpha \\text {a n d} \\| a _ {k} ^ {2} \\| < \\frac {T}{2} \\\\ - 1, \\text {o t h e r w i s e} \\end{array} \\right. \\tag {7}", + "image_path": "55e81bef01a8c824a2f7c6f0a2e9444d6a68ad6135957b6636779c18ed2d03fa.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "content": " is the ground-truth mask of actions over frames, and enforces that each iteration of the video augmentation covers the entire time interval of an action rather than randomly scattered frames. " + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\alpha = 0.4T" + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "content": " is an experimentally optimized threshold which allows a flexible frame selection of up to " + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "inline_equation", + "content": "40\\%" + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "content": " of the past " + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_k" + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "content": ". From (7), agent 2 is penalized when selects more than a half of the video for augmentation." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 274, + 545, + 287 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 274, + 545, + 287 + ], + "spans": [ + { + "bbox": [ + 305, + 274, + 545, + 287 + ], + "type": "text", + "content": "5.2. Learning the Policies for Feature Augmentation" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 292, + 545, + 435 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 292, + 545, + 435 + ], + "spans": [ + { + "bbox": [ + 304, + 292, + 545, + 435 + ], + "type": "text", + "content": "To learn " + }, + { + "bbox": [ + 304, + 292, + 545, + 435 + ], + "type": "inline_equation", + "content": "\\mu^1" + }, + { + "bbox": [ + 304, + 292, + 545, + 435 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 292, + 545, + 435 + ], + "type": "inline_equation", + "content": "\\mu^2" + }, + { + "bbox": [ + 304, + 292, + 545, + 435 + ], + "type": "text", + "content": ", we design an Actor-Critic model with a decentralized-actor deep network for computing the agents' actions, and a centralized-critic deep network for efficiently estimating action-value functions " + }, + { + "bbox": [ + 304, + 292, + 545, + 435 + ], + "type": "inline_equation", + "content": "\\hat{Q}^1" + }, + { + "bbox": [ + 304, + 292, + 545, + 435 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 292, + 545, + 435 + ], + "type": "inline_equation", + "content": "\\hat{Q}^2" + }, + { + "bbox": [ + 304, + 292, + 545, + 435 + ], + "type": "text", + "content": ", as shown in Fig. 3. The Actor-Critic framework has been demonstrated effective for continuous agent-action spaces and when the agents have individual rewards [17], as in our case. In general, decentralizing the actor network helps increase stationarity of environments with self-interested agents [37]. The centralized critic network is suitable because it allows relevant information from all of the agents to be shared toward estimating each agent's expected reward." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 436, + 545, + 508 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 436, + 545, + 508 + ], + "spans": [ + { + "bbox": [ + 305, + 436, + 545, + 508 + ], + "type": "text", + "content": "As can be seen in Fig. 3, the input to the actor network, " + }, + { + "bbox": [ + 305, + 436, + 545, + 508 + ], + "type": "inline_equation", + "content": "s_k = (\\mathcal{X}_k, \\mathcal{M}_k)" + }, + { + "bbox": [ + 305, + 436, + 545, + 508 + ], + "type": "text", + "content": ", is passed through a backbone, specified as a multi-stage temporal convolutional neural network (TCN) [11], in order to estimate the latent (deep) representation of " + }, + { + "bbox": [ + 305, + 436, + 545, + 508 + ], + "type": "inline_equation", + "content": "s_k" + }, + { + "bbox": [ + 305, + 436, + 545, + 508 + ], + "type": "text", + "content": ". Then, two distinct 1-stage TCNs take this latent representation as input and compute the frame selection" + } + ] + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 309, + 525, + 545, + 656 + ], + "blocks": [ + { + "bbox": [ + 309, + 525, + 545, + 656 + ], + "lines": [ + { + "bbox": [ + 309, + 525, + 545, + 656 + ], + "spans": [ + { + "bbox": [ + 309, + 525, + 545, + 656 + ], + "type": "image", + "image_path": "ac11775c1bb28e9621f1c50e5b0fac05631f9f124203b8fe256f102618230d56.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "lines": [ + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "text", + "content": "Figure 3. Actor-Critic model for learning policies " + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "inline_equation", + "content": "\\mu^1" + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "inline_equation", + "content": "\\mu^2" + }, + { + "bbox": [ + 304, + 666, + 545, + 712 + ], + "type": "text", + "content": " consists of several stages of temporal convolution network (TCN). The actor network predicts feature augmentation, and the centralized critic estimates the expected rewards for each policy." + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_caption" + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13509" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "inline_equation", + "content": "a_2^k" + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "text", + "content": " and feature offsets of the selected frames " + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "inline_equation", + "content": "a_k^1" + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "text", + "content": ". Finally, the predicted " + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "inline_equation", + "content": "a_k^1" + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "inline_equation", + "content": "a_2^k" + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "text", + "content": ", and latent feature of " + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "inline_equation", + "content": "s_k" + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "text", + "content": " are passed to the centralized critic - specifically, a 2-stage TCN - to estimate the expected rewards " + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "inline_equation", + "content": "\\hat{Q}_k^1 = \\hat{Q}^1 (s_k,a_k^1,a_k^2)" + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "inline_equation", + "content": "\\hat{Q}_k^2 = \\hat{Q}^2 (s_k,a_k^1,a_k^2)" + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "text", + "content": " of " + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "inline_equation", + "content": "\\mu^1" + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "inline_equation", + "content": "\\mu^2" + }, + { + "bbox": [ + 47, + 72, + 286, + 134 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 134, + 286, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 134, + 286, + 205 + ], + "spans": [ + { + "bbox": [ + 47, + 134, + 286, + 205 + ], + "type": "text", + "content": "Parameters of the proposed actor-critic deep architecture are learned using the standard temporal difference learning [21]. The critic learns to iteratively simulate the action-value function, " + }, + { + "bbox": [ + 47, + 134, + 286, + 205 + ], + "type": "inline_equation", + "content": "\\hat{Q}_k^i" + }, + { + "bbox": [ + 47, + 134, + 286, + 205 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 134, + 286, + 205 + ], + "type": "inline_equation", + "content": "i = \\{1, 2\\}" + }, + { + "bbox": [ + 47, + 134, + 286, + 205 + ], + "type": "text", + "content": ", which is later used to update parameters of the actor network. To this end, we minimize the following loss of the critic network:" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 88, + 215, + 286, + 246 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 88, + 215, + 286, + 246 + ], + "spans": [ + { + "bbox": [ + 88, + 215, + 286, + 246 + ], + "type": "interline_equation", + "content": "L _ {C} = \\sum_ {i \\in \\{1, 2 \\}} \\left(R _ {k} ^ {i} + \\gamma \\hat {Q} _ {k + 1} ^ {i} - \\hat {Q} _ {k} ^ {i}\\right) ^ {2}, \\tag {8}", + "image_path": "99eceabc9e0d825f491323d0ece5295aafdc7a8c9b5c4c6510dc58b56c43a8a8.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 257, + 286, + 281 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 257, + 286, + 281 + ], + "spans": [ + { + "bbox": [ + 47, + 257, + 286, + 281 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 257, + 286, + 281 + ], + "type": "inline_equation", + "content": "R_{k}^{i}" + }, + { + "bbox": [ + 47, + 257, + 286, + 281 + ], + "type": "text", + "content": " is given by (6) and (7), and " + }, + { + "bbox": [ + 47, + 257, + 286, + 281 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 47, + 257, + 286, + 281 + ], + "type": "text", + "content": " is the discount factor. The actor network is learned with the following loss:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 56, + 300, + 286, + 323 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 300, + 286, + 323 + ], + "spans": [ + { + "bbox": [ + 56, + 300, + 286, + 323 + ], + "type": "interline_equation", + "content": "L _ {A} ^ {i} = \\left\\| a _ {k} ^ {i} \\right\\| _ {2} ^ {2} \\cdot \\left(R _ {k} ^ {i} + \\gamma \\hat {Q} _ {k + 1} ^ {i} - \\hat {Q} _ {k} ^ {i}\\right) ^ {2}, i = \\{1, 2 \\}. \\tag {9}", + "image_path": "5400d4793b0b140ff0cee72bf6efefab9f30f8fc25abb99141ee4595787f287d.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "spans": [ + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "text", + "content": "A proof in [37] shows that minimizing " + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "inline_equation", + "content": "L_{C}" + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "inline_equation", + "content": "L_{A}" + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "text", + "content": " in (8) and (9) optimizes " + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "inline_equation", + "content": "\\mu^{1}" + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "inline_equation", + "content": "\\mu^{2}" + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "text", + "content": " so they manage to achieve maximal rewards " + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "inline_equation", + "content": "R^{1}" + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "inline_equation", + "content": "R^{2}" + }, + { + "bbox": [ + 47, + 331, + 286, + 368 + ], + "type": "text", + "content": " given by (6) and (7), as desired." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 380, + 99, + 392 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 380, + 99, + 392 + ], + "spans": [ + { + "bbox": [ + 47, + 380, + 99, + 392 + ], + "type": "text", + "content": "6. Results" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 401, + 286, + 520 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 401, + 286, + 520 + ], + "spans": [ + { + "bbox": [ + 46, + 401, + 286, + 520 + ], + "type": "text", + "content": "Datasets include three benchmarks: Breakfast [22], GTEA [12], and 50Salads [36]. For each dataset, we precompute the standard I3D frame features without any self-supervision, fine-tuning, or data augmentation, as in [11]. Breakfast has 1712 videos with 48 action classes, GTEA shows 7 complex activities, each specified in terms of 11 action classes including the background class. 50Salads consists of 50 videos with 17 action classes. For Breakfast, GTEA, and 50Salads, we perform the standard 4-fold, 4-fold, and 5-fold cross validation, respectively." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 521, + 286, + 592 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 521, + 286, + 592 + ], + "spans": [ + { + "bbox": [ + 46, + 521, + 286, + 592 + ], + "type": "text", + "content": "Metrics. Mean-of-Frame (MoF) is the average framework classification accuracy. Edit score counts edit operations to make the predicted and ground-truth sequences equivalent. F1 score counts true positives when a temporal intersection between the predicted and ground-truth segments is " + }, + { + "bbox": [ + 46, + 521, + 286, + 592 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 46, + 521, + 286, + 592 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 521, + 286, + 592 + ], + "type": "inline_equation", + "content": "25\\%" + }, + { + "bbox": [ + 46, + 521, + 286, + 592 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 521, + 286, + 592 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 46, + 521, + 286, + 592 + ], + "type": "text", + "content": ", denoted as F1@10,25,50." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 594, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 286, + 713 + ], + "type": "text", + "content": "Implementation details. The Actor-Critic has the same layers as MS-TCN [11]. One stage consists of 10 convolution layers with an increasing dilation rate and feature maps with size 128. The mask backbone and feature backbone each represents a 1-stage TCN. Their outputs are, first, concatenated, then, passed to a 4-stage MS-TCN, and, finally, input to the agents' heads. Agent 1's head is a 2-stage MS-TCN. Agent 2's head is a 1-stage TCN. The critic network is a 2-stage MS-TCN. The learning rate for the actor-critic training is 0.0001. Our training of the meta-model is run for" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 72, + 545, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 266 + ], + "type": "text", + "content": "30 epochs. The NMS threshold is set to 0.5, and the minimum IOU is set to 0. The discount factor " + }, + { + "bbox": [ + 304, + 72, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\gamma = 0.99" + }, + { + "bbox": [ + 304, + 72, + 545, + 266 + ], + "type": "text", + "content": ". The policy training on Tesla-V100s for GTEA takes 3 hours. The MCTS algorithm runs 1000 node expansions in a couple of seconds. The maximum tree width is 200. The maximum tree depth is " + }, + { + "bbox": [ + 304, + 72, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\hat{\\lambda} + 2\\sqrt{\\hat{\\lambda}}" + }, + { + "bbox": [ + 304, + 72, + 545, + 266 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 304, + 72, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\hat{\\lambda}" + }, + { + "bbox": [ + 304, + 72, + 545, + 266 + ], + "type": "text", + "content": " is the average transcript length of the training set. The number of epochs in the fine-tuning on the original and augmented data is 50 epochs for MS-TCN, 100 epochs for ASFormer, and 50 epochs for BCN. The meta-training of the meta-model increases complexity compared to baseline approaches. It is important to separate the time for training an action segmentation model, and the time for our meta-training. Our meta-training can be viewed as a part of the dataset preparation, which takes significantly less time than manually collecting and annotating real videos." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 275, + 511, + 286 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 275, + 511, + 286 + ], + "spans": [ + { + "bbox": [ + 305, + 275, + 511, + 286 + ], + "type": "text", + "content": "6.1. Ablation Studies of MS-TCN on GTEA" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 293, + 545, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 293, + 545, + 533 + ], + "spans": [ + { + "bbox": [ + 304, + 293, + 545, + 533 + ], + "type": "text", + "content": "The training dataset size. Tab. 1 reports how MS-TCN performance on GTEA changes as a function of two variables: (i) the number of training transcripts; and (ii) the total number of original and augmented videos – both expressed as the increase factor of the original set. Tab. 1 shows that when the original set of training videos is tripled such that there are " + }, + { + "bbox": [ + 304, + 293, + 545, + 533 + ], + "type": "inline_equation", + "content": "20\\%" + }, + { + "bbox": [ + 304, + 293, + 545, + 533 + ], + "type": "text", + "content": " of new transcripts, MS-TCN achieves the best performance for all of the metrics, and this setting is used in the sequel. Too many augmentations using the same input video leads to similar data outputs, and consequently to overfitting in training of an action segmentation model. Note that testing the transcript augmentation as a standalone contribution is inappropriate and reduces performance (second row), since new transcripts need to be realized as new videos. These new videos are Frankenstein-like constructs from multiple real videos, and hence have highly unrealistic action transitions, and incoherent and sometimes impossible human motions. Therefore, the new videos require additional frame-feature augmentation to provide useful data augmentation." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 534, + 545, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 534, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 304, + 534, + 545, + 689 + ], + "type": "text", + "content": "Alternatives for generating transcripts. Tab. 2 compares two alternative methods for generating transcripts – namely, auto-regression and our UCT – in terms of: (i) edit distance to the ground-truth transcripts, and (ii) expected reward given by (1). The two metrics are averaged over the top " + }, + { + "bbox": [ + 304, + 534, + 545, + 689 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 304, + 534, + 545, + 689 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 534, + 545, + 689 + ], + "type": "inline_equation", + "content": "20\\%" + }, + { + "bbox": [ + 304, + 534, + 545, + 689 + ], + "type": "text", + "content": " of generated transcripts that are the closest to the ground-truth transcripts. The auto-regressive model is a Transformer Network [35] trained with the cross-entropy loss to predict the next action class given an input sequence of action classes. From Tab. 2, our UCT generates transcripts which are more similar to the ground-truth ones than those produced by auto-regression. Also, the average likelihoods for UCT and ground truth are nearly the same." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": "RL vs Non-RL for frame-feature augmentation. Tab. 3 compares the proposed reinforcement learning and" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13510" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 70, + 291, + 150 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 291, + 150 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 291, + 150 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 291, + 150 + ], + "type": "table", + "html": "
#TranscriptsTrain. set sizeF1@10,25,50EditMoF
1×1×87.384.972.482.078.0
1.1×1×85.281.169.780.074.9
1×2×89.888.577.686.879.5
1.1×2×90.588.677.987.178.9
1.2×3×90.988.279.288.879.6
1.2×4×89.187.778.989.079.7
1.2×5×89.087.075.685.778.2
", + "image_path": "e12669ff5e0d47930af944168521ff2a337ed9ad9b72b9be0fb85e408a3edd73.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 48, + 253, + 293, + 313 + ], + "blocks": [ + { + "bbox": [ + 46, + 154, + 288, + 243 + ], + "lines": [ + { + "bbox": [ + 46, + 154, + 288, + 243 + ], + "spans": [ + { + "bbox": [ + 46, + 154, + 288, + 243 + ], + "type": "text", + "content": "Table 1. MS-TCN performance on GTEA as a function of the number of training transcripts, and the number of original and augmented videos used for training -both expressed as the increase factor of the original training set. When our augmentation triples the set of training videos such that there are " + }, + { + "bbox": [ + 46, + 154, + 288, + 243 + ], + "type": "inline_equation", + "content": "20\\%" + }, + { + "bbox": [ + 46, + 154, + 288, + 243 + ], + "type": "text", + "content": " of newly generated transcripts, MS-TCN achieves the best performance. The top row is without any augmentation, and the second from the top row is for only feature augmentation without new transcripts." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 253, + 293, + 313 + ], + "lines": [ + { + "bbox": [ + 48, + 253, + 293, + 313 + ], + "spans": [ + { + "bbox": [ + 48, + 253, + 293, + 313 + ], + "type": "table", + "html": "
MethodEdit dist. (%) Top 10%Edit dist. (%) Top 20%Likelihood Top 20%
Auto-regression19.522.00.59e-4
UCT14.015.21.41e-4
Ground truth--1.45e-4
", + "image_path": "4ef8915bd572855a453fb0e2969c189e1063f4845830b2083a81c297b69e35df.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 49, + 392, + 282, + 463 + ], + "blocks": [ + { + "bbox": [ + 46, + 316, + 288, + 383 + ], + "lines": [ + { + "bbox": [ + 46, + 316, + 288, + 383 + ], + "spans": [ + { + "bbox": [ + 46, + 316, + 288, + 383 + ], + "type": "text", + "content": "Table 2. Comparison of two alternative transcript generation methods – auto-regression by a Transformer Network [35], and our proposed UCT – in terms of an average edit distance between the generated and ground-truth transcripts for GTEA, and their average likelihood given by (1). The two metrics are averaged over the top " + }, + { + "bbox": [ + 46, + 316, + 288, + 383 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 46, + 316, + 288, + 383 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 316, + 288, + 383 + ], + "type": "inline_equation", + "content": "20\\%" + }, + { + "bbox": [ + 46, + 316, + 288, + 383 + ], + "type": "text", + "content": " of generated transcripts closest to the ground-truth." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 49, + 392, + 282, + 463 + ], + "lines": [ + { + "bbox": [ + 49, + 392, + 282, + 463 + ], + "spans": [ + { + "bbox": [ + 49, + 392, + 282, + 463 + ], + "type": "table", + "html": "
Frame AugmentationF1@10,25,50EditMoF
No augmentation [11]85.883.469.879.076.3
Noise85.783.271.979.677.5
Non-RL (Seq)83.180.969.176.276.5
Non-RL (All)83.981.570.477.677.7
Our RL-based90.988.279.288.879.6
", + "image_path": "f8be5464269410f877c8420388098a97267602f30fb4ada525552eade1a2f2c0.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 75, + 517, + 257, + 563 + ], + "blocks": [ + { + "bbox": [ + 46, + 463, + 286, + 506 + ], + "lines": [ + { + "bbox": [ + 46, + 463, + 286, + 506 + ], + "spans": [ + { + "bbox": [ + 46, + 463, + 286, + 506 + ], + "type": "text", + "content": "Table 3. MS-TCN performance on GTAE, when using the best data augmentation setting given in Tab. 1, and for alternative strategies of frame-feature augmentation. Supervised learning in \"Non-RL\" decreases the performance of MS-TCN." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 75, + 517, + 257, + 563 + ], + "lines": [ + { + "bbox": [ + 75, + 517, + 257, + 563 + ], + "spans": [ + { + "bbox": [ + 75, + 517, + 257, + 563 + ], + "type": "table", + "html": "
PoliciesF1@10,25,50EditMoF
μ1/1088.585.074.783.878.2
μ1/2087.484.874.184.577.8
μ1/μ290.988.279.288.879.6
", + "image_path": "2cb39568cf66c71f10e0c6e024b9f151a647905adbae1a539b62d1c3c7237be3.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "content": "an alternative supervised learning for frame-feature augmentation, when using the best data augmentation setting given in Tab. 1. We consider several baselines. \"Noise\" refers to simply adding Gaussian noise with zero mean and 0.01 variance to the original deep features of frames, as the original I3D features have an average value of 0.2 and variance 0.06. From Tab. 3, such a frame-feature augmentation with Gaussian noise barely has any effect on MS-TCN's performance. \"Non-RL\" is another baseline that uses su" + } + ] + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 312, + 70, + 538, + 105 + ], + "blocks": [ + { + "bbox": [ + 46, + 563, + 286, + 585 + ], + "lines": [ + { + "bbox": [ + 46, + 563, + 286, + 585 + ], + "spans": [ + { + "bbox": [ + 46, + 563, + 286, + 585 + ], + "type": "text", + "content": "Table 4. MS-TCN performance on GTAE for the proposed multiagent " + }, + { + "bbox": [ + 46, + 563, + 286, + 585 + ], + "type": "inline_equation", + "content": "(\\mu_{1} / \\mu_{2})" + }, + { + "bbox": [ + 46, + 563, + 286, + 585 + ], + "type": "text", + "content": " and the alternative single-agent " + }, + { + "bbox": [ + 46, + 563, + 286, + 585 + ], + "type": "inline_equation", + "content": "(\\mu_{1} / 10" + }, + { + "bbox": [ + 46, + 563, + 286, + 585 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 46, + 563, + 286, + 585 + ], + "type": "inline_equation", + "content": "\\mu_{1} / 20)" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 312, + 70, + 538, + 105 + ], + "lines": [ + { + "bbox": [ + 312, + 70, + 538, + 105 + ], + "spans": [ + { + "bbox": [ + 312, + 70, + 538, + 105 + ], + "type": "table", + "html": "
Class transition2, 52, 75, 98, 1010, 4
# Original dataset11233
# Augmented dataset22355
", + "image_path": "c36c5953fc693afcf6a3f761bd11afd17e2e4a5dbbf664251cc42945dc3c3406.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 105, + 545, + 126 + ], + "lines": [ + { + "bbox": [ + 306, + 105, + 545, + 126 + ], + "spans": [ + { + "bbox": [ + 306, + 105, + 545, + 126 + ], + "type": "text", + "content": "Table 5. Count of the least represented action transitions in the original and augmented training sets of GTEA." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 147, + 545, + 374 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 147, + 545, + 374 + ], + "spans": [ + { + "bbox": [ + 304, + 147, + 545, + 374 + ], + "type": "text", + "content": "pervised learning for training the meta-model, as depicted in Fig. 1 (bottom left). In \"Non-RL\" the meta-model is a 1-stage TCN which outputs the offset feature for a given original feature at the input. As shown in Fig. 1 (bottom left), the resulting augmented feature is then passed to the pre-trained action segmenter. The meta-model is trained based on the cross-entropy loss of the pre-trained action segmenter, which serves as an oracle to ensure that the augmented feature remains in the action class of the original frame feature. For \"Non-RL\", we also regularize the resulting augmented feature to be different from the original feature with the standard contrastive loss. Moreover, we study two versions of \"Non-RL\" - one where all features of the entire video are modified at once, called \"Non-RL (All)\"; and the other with a sequential modification of frame features one action segment at a time, called \"Non-RL (Seq)\" From Tab. 3, both \"Non-RL (All)\" and \"Non-RL (Seq)\" decrease MS-TCN's performance. More details on \"Non-RL\" are presented in the supplement." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "spans": [ + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "text", + "content": "Policy. Tab. 4 compares MS-TCN performance on GTAE for our multi-agent formulation and an alternative single-agent feature augmentation. The latter does not learn frame masking, and hence does not have our agent 2. The single-agent, denoted as " + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "inline_equation", + "content": "\\mu_1 / 10" + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "inline_equation", + "content": "\\mu_1 / 20" + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "text", + "content": ", uses only policy " + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "inline_equation", + "content": "\\mu_1" + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "text", + "content": " for augmenting frame features. The values 10 and 20 indicate the percent of video randomly selected for augmentation at each policy iteration. Our multi-agent, denoted as " + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "inline_equation", + "content": "\\mu_1 / \\mu_2" + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "text", + "content": ", uses both " + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "inline_equation", + "content": "\\mu_1" + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "inline_equation", + "content": "\\mu_2" + }, + { + "bbox": [ + 304, + 374, + 545, + 495 + ], + "type": "text", + "content": " policies. Tab. 4 shows that adding the second agent significantly improves the results." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 495, + 545, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 495, + 545, + 602 + ], + "spans": [ + { + "bbox": [ + 304, + 495, + 545, + 602 + ], + "type": "text", + "content": "Improving transcripts variability. Generating new transcripts modify the total count of action transition initially present in the original set of transcripts. The advantage of our MCTS based generation approach is the emphasis on exploration. The number of poorly represented action transitions are increased with the new transcripts in training. Tab. 5 shows some example action transitions that are the least represented in the original training set get at least one new instance when adding the generated transcripts." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 611, + 456, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 611, + 456, + 624 + ], + "spans": [ + { + "bbox": [ + 306, + 611, + 456, + 624 + ], + "type": "text", + "content": "6.2. Impact of MVGA on SOTA" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "text", + "content": "The top of Tab. 6 reports results of state-of-the-art (SOTA) fully supervised methods that do not use video augmentation in training (some of them use sophisticated post-processing, which we do not have). Tab. 6 also shows how MVGA affects performance of SOTA approaches – including: MS-TCN[11], BCN [40], ASFormer [43], and BridgePrompt [26] – on Breakfast, GTAE, and 50Salads. As can" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13511" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 70, + 544, + 236 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 544, + 236 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 544, + 236 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 544, + 236 + ], + "type": "table", + "html": "
DatasetBreakfastGTEA50Salads
MethodF1@10,25,50EditMoFF1@10,25,50EditMoFF1@10,25,50EditMoF
MSTCN++ [27]64.158.645.965.667.687.886.274.482.678.980.778.570.174.383.7
ASRF [18]74.368.956.172.467.689.487.879.883.777.384.983.577.379.384.5
HASR [1]74.769.557.071.969.489.287.274.884.576.986.685.778.581.083.9
SSTDA [7]75.069.155.273.770.290.089.178.086.279.883.081.573.875.883.2
G2L [13]74.969.055.273.370.789.987.375.884.678.580.378.069.873.482.2
UVAST [2]76.770.056.668.286.277.169.754.290.562.281.270.483.977.169.7
MSTCN [11]52.648.137.961.766.385.883.469.879.076.376.374.064.567.980.7
MSTCN (Ours)58.154.644.463.466.887.384.972.482.078.075.873.866.868.282.7
MSTCN + MVGA68.966.155.868.171.190.988.879.288.279.680.177.971.274.183.2
BCN [40]68.765.555.066.270.488.587.177.384.479.882.381.374.074.384.4
BCN + MVGA70.867.757.368.371.891.390.080.686.780.583.782.475.877.285.6
ASFormer [43]76.070.657.475.073.590.188.879.284.679.785.183.476.079.685.6
ASFormer + MVGA75.672.159.776.874.291.390.579.386.480.386.384.978.781.386.0
Bridge-Prompt [26]94.192.083.091.681.289.287.881.383.888.1
Bridge-Prompt + MVGA95.293.484.892.182.690.889.483.286.188.9
", + "image_path": "23fce50eacc8a6e3ae4e6e352f16f754cb7a4d943a77e8324f7d44a6947d232c.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 48, + 238, + 545, + 258 + ], + "lines": [ + { + "bbox": [ + 48, + 238, + 545, + 258 + ], + "spans": [ + { + "bbox": [ + 48, + 238, + 545, + 258 + ], + "type": "text", + "content": "Table 6. Impact of MVGA on SOTA methods on Breakfast, GTEA and 50Salads, and comparison with the other SOTA approaches that do not use data augmentation." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 54, + 268, + 539, + 347 + ], + "blocks": [ + { + "bbox": [ + 54, + 268, + 539, + 347 + ], + "lines": [ + { + "bbox": [ + 54, + 268, + 539, + 347 + ], + "spans": [ + { + "bbox": [ + 54, + 268, + 539, + 347 + ], + "type": "table", + "html": "
DatasetBreakfastGTEA50Salads
MethodF1@10,25,50EditMoFF1@10,25,50EditMoFF1@10,25,50EditMoF
MSTCN + C2F[34]58.255.047.862.966.586.283.578.178.876.577.374.265.567.380.8
MSTCN + Speed55.052.741.960.165.984.880.866.178.875.777.375.967.868.881.2
MSTCN + MVGA68.966.155.868.171.190.988.879.288.279.680.177.971.274.183.2
ASFormer + C2F [34]75.872.357.575.272.990.388.078.884.278.984.582.676.178.784.0
ASFormer + Speed75.269.156.974.871.989.387.277.785.278.584.482.975.177.285.1
ASFormer + MVGA75.672.159.776.874.291.390.579.386.480.386.384.978.781.386.0
", + "image_path": "e413f947d2bd87bbe4ebb7b0c375a09cfd216dd116a4d778d698e0982187e5fd.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 123, + 348, + 470, + 357 + ], + "lines": [ + { + "bbox": [ + 123, + 348, + 470, + 357 + ], + "spans": [ + { + "bbox": [ + 123, + 348, + 470, + 357 + ], + "type": "text", + "content": "Table 7. Comparison of different data augmentation methods on Breakfast, GTEA and 50Salads." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 376, + 287, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 376, + 287, + 568 + ], + "spans": [ + { + "bbox": [ + 49, + 376, + 287, + 568 + ], + "type": "text", + "content": "be seen, for all of the four SOTA approaches, data augmentation by MVGA consistently produces performance gains relative to their respective performance without data augmentation. For instance, MSTCN+MVGA outperforms both MSTCN [11] and its more advanced relative MSTCN++ [27] without data augmentation. MVGA also improves the original ASFormer [43] producing the new state of the art performance on Breakfast. Applying MVGA on the features provided by Bridge-Prompt [26] and following the same training procedure as for the ASFormer gives the method Bridge-Prompt+MVGA with the best results on GTAE and 50Salads. In Tab. 6, we could not report Bridge-Prompt+MVGA performance on Breakfast, since the Bridge-Prompt model for action segmentation on Breakfast is not publicly available, and our own training of Bridge-Prompt on Breakfast gave poor results." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 570, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 570, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 49, + 570, + 287, + 713 + ], + "type": "text", + "content": "Video augmentation has been considered in the context of self-supervised learning (typically as a part of pretraining). However, a comparison with such methods is beyond our scope, because MVGA directly allows for the unified fully supervised training on a larger, augmented training dataset. In Tab. 7, we compare MVGA with some baseline video augmentation methods which also directly enable fully supervised learning, including Speed and C2F [34]. The former randomly selects certain action instances in each original training video, and performs \"speeding-up\" (i.e., frame subsampling) or \"slowing-down\" (i.e., frame upsampling with interpolation) of their temporal intervals," + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 376, + 545, + 473 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 376, + 545, + 473 + ], + "spans": [ + { + "bbox": [ + 306, + 376, + 545, + 473 + ], + "type": "text", + "content": "and thus doubles the original training set. C2F randomly selects certain time intervals in every original training video. Then, for each selected interval, C2F assigns the dominant ground-truth action class with the largest temporal support in that interval, and also replaces all frame features within the interval with their max-pooled feature. As can be seen in Tab. 7, MVGA provides for better data augmentation for MS-TCN and ASFormer than Speed and C2F." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 495, + 378, + 506 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 495, + 378, + 506 + ], + "spans": [ + { + "bbox": [ + 306, + 495, + 378, + 506 + ], + "type": "text", + "content": "7. Conclusion" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 518, + 545, + 686 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 518, + 545, + 686 + ], + "spans": [ + { + "bbox": [ + 306, + 518, + 545, + 686 + ], + "type": "text", + "content": "We have specified video data augmentation for action segmentation within the reinforcement learning framework. Our approach generates new action transcripts and their corresponding new videos, as well as modifies the feature embedding of video frames. The transcript generation uses the efficient Monte-Carlo Tree Search to produce new, legal, high-likelihood action sequences. Optimal amount and temporal locations of feature changes in the video are learned with a two-agent actor-critic network. Our video augmentation in training of representative, state-of-the-art, convolutional and transformer-based action segmenters leads to their significant performance gains on the benchmark Breakfast, GTEA, and 50salads datasets, in comparison to their original training without video augmentation." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 689, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 712 + ], + "type": "text", + "content": "Acknowledgments This work was supported in part by DARPA MCS Award N66001-19-2-4035." + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "13512" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 714 + ], + "type": "list", + "angle": 0, + "index": 17, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "type": "text", + "content": "[1] Hyemin Ahn and Dongheui Lee. Refining action segmentation with hierarchical video representations. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 16302-16310, 2021." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 137, + 288, + 180 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 137, + 288, + 180 + ], + "spans": [ + { + "bbox": [ + 53, + 137, + 288, + 180 + ], + "type": "text", + "content": "[2] Nadine Behrmann, S Alireza Golestaneh, Zico Kolter, Juergen Gall, and Mehdi Noroozi. Unified fully and timestamp supervised temporal action segmentation via sequence to sequence translation. arXiv preprint arXiv:2209.00638, 2022." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 182, + 287, + 225 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 182, + 287, + 225 + ], + "spans": [ + { + "bbox": [ + 53, + 182, + 287, + 225 + ], + "type": "text", + "content": "[3] Miriam Bellver Bueno, Xavier Giro-i Nieto, Ferran Marqués, and Jordi Torres. Hierarchical object detection with deep reinforcement learning. Deep Learning for Image Processing Applications, 31(164):3, 2017." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 227, + 288, + 270 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 227, + 288, + 270 + ], + "spans": [ + { + "bbox": [ + 53, + 227, + 288, + 270 + ], + "type": "text", + "content": "[4] Juan C Caicedo and Svetlana Lazebnik. Active object localization with deep reinforcement learning. In Proceedings of the IEEE international conference on computer vision, pages 2488-2496, 2015." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 272, + 287, + 304 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 272, + 287, + 304 + ], + "spans": [ + { + "bbox": [ + 53, + 272, + 287, + 304 + ], + "type": "text", + "content": "[5] Joao Carreira and Andrew Zisserman. Quo vadis, action recognition? a new model and the kinetics dataset. In CVPR, 2017." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 306, + 287, + 350 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 306, + 287, + 350 + ], + "spans": [ + { + "bbox": [ + 53, + 306, + 287, + 350 + ], + "type": "text", + "content": "[6] Boyu Chen, Dong Wang, Peixia Li, Shuang Wang, and Huchuan Lu. Real-time actor-critic tracking. In Proceedings of the European conference on computer vision (ECCV), pages 318-334, 2018." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 351, + 287, + 384 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 351, + 287, + 384 + ], + "spans": [ + { + "bbox": [ + 53, + 351, + 287, + 384 + ], + "type": "text", + "content": "[7] Min-Hung Chen, Baopu Li, Yingze Bao, Ghassan Al-Regib, and Zsolt Kira. Action segmentation with joint self-supervised temporal domain adaptation. In CVPR, 2020." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 385, + 287, + 439 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 385, + 287, + 439 + ], + "spans": [ + { + "bbox": [ + 53, + 385, + 287, + 439 + ], + "type": "text", + "content": "[8] César Roberto de Souza, Adrien Gaidon, Yohann Cabon, Naila Murray, and Antonio Manuel López. Generating human action videos by coupling 3d game engines and probabilistic graphical models. International Journal of Computer Vision, 128(5):1505-1536, 2020." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 441, + 287, + 474 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 441, + 287, + 474 + ], + "spans": [ + { + "bbox": [ + 53, + 441, + 287, + 474 + ], + "type": "text", + "content": "[9] César Roberto de Souza12, Adrien Gaidon, Yohann Cabon, and Antonio Manuel López. Procedural generation of videos to train deep action recognition networks. 2017." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 475, + 287, + 507 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 475, + 287, + 507 + ], + "spans": [ + { + "bbox": [ + 48, + 475, + 287, + 507 + ], + "type": "text", + "content": "[10] Li Ding and Chenliang Xu. Weakly-supervised action segmentation with iterative soft boundary assignment. In CVPR, June 2018." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 509, + 287, + 542 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 509, + 287, + 542 + ], + "spans": [ + { + "bbox": [ + 48, + 509, + 287, + 542 + ], + "type": "text", + "content": "[11] Yazan Abu Farha and Jurgen Gall. MS-TCN: Multi-stage temporal convolutional network for action segmentation. In CVPR, 2019." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 544, + 287, + 577 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 544, + 287, + 577 + ], + "spans": [ + { + "bbox": [ + 48, + 544, + 287, + 577 + ], + "type": "text", + "content": "[12] Alireza Fathi, Xiaofeng Ren, and James M Rehg. Learning to recognize objects in egocentric activities. In CVPR 2011, pages 3281-3288. IEEE, 2011." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 578, + 287, + 610 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 578, + 287, + 610 + ], + "spans": [ + { + "bbox": [ + 48, + 578, + 287, + 610 + ], + "type": "text", + "content": "[13] Shang-Hua Gao, Qi Han, Zhong-Yu Li, Pai Peng, Liang Wang, and Ming-Ming Cheng. Global2local: Efficient structure search for video action segmentation. In CVPR, 2021." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 612, + 287, + 655 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 612, + 287, + 655 + ], + "spans": [ + { + "bbox": [ + 48, + 612, + 287, + 655 + ], + "type": "text", + "content": "[14] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. Communications of the ACM, 63(11):139-144, 2020." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 657, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 657, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 657, + 287, + 689 + ], + "type": "text", + "content": "[15] Junling Hu and Michael P Wellman. Nash q-learning for general-sum stochastic games. Journal of machine learning research, 4(Nov):1039-1069, 2003." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "type": "text", + "content": "[16] Chen Huang, Simon Lucey, and Deva Ramanan. Learning policies for adaptive tracking with deep feature cascades. In" + } + ] + } + ], + "index": 16 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 35, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "text", + "content": "Proceedings of the IEEE international conference on computer vision, pages 105-114, 2017." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 95, + 545, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 95, + 545, + 128 + ], + "spans": [ + { + "bbox": [ + 308, + 95, + 545, + 128 + ], + "type": "text", + "content": "[17] Shariq Iqbal and Fei Sha. Actor-attention-critic for multiagent reinforcement learning. In International conference on machine learning, pages 2961–2970. PMLR, 2019." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 129, + 545, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 129, + 545, + 161 + ], + "spans": [ + { + "bbox": [ + 308, + 129, + 545, + 161 + ], + "type": "text", + "content": "[18] Yuchi Ishikawa, Seito Kasai, Yoshimitsu Aoki, and Hirokatsu Kataoka. Alleviating over-segmentation errors by detecting action boundaries. In WACV, 2021." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 162, + 545, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 162, + 545, + 205 + ], + "spans": [ + { + "bbox": [ + 308, + 162, + 545, + 205 + ], + "type": "text", + "content": "[19] Takashi Isobe, Jian Han, Fang Zhuz, Yali Liy, and Shengjin Wang. Intra-clip aggregation for video person re-identification. In 2020 IEEE International Conference on Image Processing (ICIP), pages 2336-2340. IEEE, 2020." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 206, + 545, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 206, + 545, + 239 + ], + "spans": [ + { + "bbox": [ + 308, + 206, + 545, + 239 + ], + "type": "text", + "content": "[20] Levente Kocsis and Csaba Szepesvári. Bandit based montecarlo planning. In European conference on machine learning, pages 282-293. Springer, 2006." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 239, + 545, + 261 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 239, + 545, + 261 + ], + "spans": [ + { + "bbox": [ + 308, + 239, + 545, + 261 + ], + "type": "text", + "content": "[21] Vijay Konda and John Tsitsiklis. Actor-critic algorithms. Advances in neural information processing systems, 12, 1999." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 262, + 545, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 262, + 545, + 293 + ], + "spans": [ + { + "bbox": [ + 308, + 262, + 545, + 293 + ], + "type": "text", + "content": "[22] Hilde Kuehne, Ali Arslan, and Thomas Serre. The language of actions: Recovering the syntax and semantics of goal-directed human activities. In CVPR, 2014." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 294, + 545, + 327 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 294, + 545, + 327 + ], + "spans": [ + { + "bbox": [ + 308, + 294, + 545, + 327 + ], + "type": "text", + "content": "[23] Colin Lea, Michael D. Flynn, Rene Vidal, Austin Reiter, and Gregory D. Hager. Temporal convolutional networks for action segmentation and detection. In CVPR, 2017." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 327, + 545, + 358 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 327, + 545, + 358 + ], + "spans": [ + { + "bbox": [ + 308, + 327, + 545, + 358 + ], + "type": "text", + "content": "[24] Peng Lei and Sinisa Todorovic. Temporal deformable residual networks for action segmentation in videos. In CVPR, 2018." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 360, + 545, + 404 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 360, + 545, + 404 + ], + "spans": [ + { + "bbox": [ + 308, + 360, + 545, + 404 + ], + "type": "text", + "content": "[25] Jie Li, Mingqiang Yang, Yupeng Liu, Yanyan Wang, Qinghe Zheng, and Deqiang Wang. Dynamic hand gesture recognition using multi-direction 3d convolutional neural networks. Engineering Letters, 27(3), 2019." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 405, + 545, + 459 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 405, + 545, + 459 + ], + "spans": [ + { + "bbox": [ + 308, + 405, + 545, + 459 + ], + "type": "text", + "content": "[26] Muheng Li, Lei Chen, Yueqi Duan, Zhilan Hu, Jianjiang Feng, Jie Zhou, and Jiwen Lu. Bridge-prompt: Towards ordinal action understanding in instructional videos. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 19880-19889, 2022." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 460, + 545, + 503 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 460, + 545, + 503 + ], + "spans": [ + { + "bbox": [ + 308, + 460, + 545, + 503 + ], + "type": "text", + "content": "[27] Shi-Jie Li, Yazan AbuFarha, Yun Liu, Ming-Ming Cheng, and Juergen Gall. MS-TCN++: Multi-stage temporal convolutional network for action segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 308, + 504, + 545, + 569 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 504, + 545, + 569 + ], + "spans": [ + { + "bbox": [ + 308, + 504, + 545, + 569 + ], + "type": "text", + "content": "[28] Xuan Liao, Wenhao Li, Qisen Xu, Xiangfeng Wang, Bo Jin, Xiaoyun Zhang, Yanfeng Wang, and Ya Zhang. Iteratively-refined interactive 3d medical image segmentation with multi-agent reinforcement learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 9394-9402, 2020." + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 308, + 570, + 545, + 603 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 570, + 545, + 603 + ], + "spans": [ + { + "bbox": [ + 308, + 570, + 545, + 603 + ], + "type": "text", + "content": "[29] Shiqi Lin, Tao Yu, Ruoyu Feng, Xin Li, Xin Jin, and Zhibo Chen. Local patch autoaugment with multi-agent collaboration. arXiv preprint arXiv:2103.11099, 2021." + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 308, + 604, + 545, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 604, + 545, + 624 + ], + "spans": [ + { + "bbox": [ + 308, + 604, + 545, + 624 + ], + "type": "text", + "content": "[30] Michael L Littman et al. Friend-or-foe q-learning in general-sum games. In ICML, volume 1, pages 322–328, 2001." + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 308, + 625, + 545, + 658 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 625, + 545, + 658 + ], + "spans": [ + { + "bbox": [ + 308, + 625, + 545, + 658 + ], + "type": "text", + "content": "[31] Ze Liu, Jia Ning, Yue Cao, Yixuan Wei, Zheng Zhang, Stephen Lin, and Han Hu. Video swim transformer. arXiv preprint arXiv:2106.13230, 2021." + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 308, + 658, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 658, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 658, + 545, + 713 + ], + "type": "text", + "content": "[32] Chaofan Ma, Qisen Xu, Xiangfeng Wang, Bo Jin, Xiaoyun Zhang, Yanfeng Wang, and Ya Zhang. Boundary-aware supervoxel-level iteratively refined interactive 3d image segmentation with multi-agent reinforcement learning. IEEE Transactions on Medical Imaging, 40(10):2563-2574, 2020." + } + ] + } + ], + "index": 34 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13513" + } + ] + } + ], + "index": 36 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 553 + ], + "type": "list", + "angle": 0, + "index": 11, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 127 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 127 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 127 + ], + "type": "text", + "content": "[33] Naima Otberdout, Mohammed Daoudi, Anis Kacem, Lahoucine Ballihi, and Stefano Berretti. Dynamic facial expression generation on hilbert hypersphere with conditional Wasserstein generative adversarial nets. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 129, + 287, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 129, + 287, + 161 + ], + "spans": [ + { + "bbox": [ + 49, + 129, + 287, + 161 + ], + "type": "text", + "content": "[34] Dipika Singhania, Rahul Rahaman, and Angela Yao. Coarse to fine multi-resolution temporal convolutional network. In CVPR, 2021." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 163, + 288, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 163, + 288, + 228 + ], + "spans": [ + { + "bbox": [ + 49, + 163, + 288, + 228 + ], + "type": "text", + "content": "[35] Li Siyao, Weijiang Yu, Tianpei Gu, Chunze Lin, Quan Wang, Chen Qian, Chen Change Loy, and Ziwei Liu. Bailando: 3d dance generation by actor-critic gpt with choreographic memory. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11050-11059, 2022." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 230, + 288, + 284 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 230, + 288, + 284 + ], + "spans": [ + { + "bbox": [ + 49, + 230, + 288, + 284 + ], + "type": "text", + "content": "[36] Sebastian Stein and Stephen J McKenna. Combining embedded accelerometers with computer vision for recognizing food preparation activities. In Proceedings of the 2013 ACM international joint conference on Pervasive and ubiquitous computing, pages 729-738, 2013." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 285, + 287, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 285, + 287, + 308 + ], + "spans": [ + { + "bbox": [ + 49, + 285, + 287, + 308 + ], + "type": "text", + "content": "[37] Richard S Sutton and Andrew G Barto. Reinforcement learning: An introduction. MIT press, 2018." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 309, + 287, + 341 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 309, + 287, + 341 + ], + "spans": [ + { + "bbox": [ + 49, + 309, + 287, + 341 + ], + "type": "text", + "content": "[38] Liangliang Wang, Lianzheng Ge, Ruifeng Li, and Yajun Fang. Three-stream cnns for action recognition. Pattern Recognition Letters, 92:33-40, 2017." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 342, + 287, + 384 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 342, + 287, + 384 + ], + "spans": [ + { + "bbox": [ + 49, + 342, + 287, + 384 + ], + "type": "text", + "content": "[39] Yuqing Wang, Zhaoliang Xu, Xinlong Wang, Chunhua Shen, Baoshan Cheng, Hao Shen, and Huaxia Xia. End-to-end video instance segmentation with transformers. In CVPR, 2021." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 387, + 287, + 419 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 387, + 287, + 419 + ], + "spans": [ + { + "bbox": [ + 49, + 387, + 287, + 419 + ], + "type": "text", + "content": "[40] Zhenzhi Wang, Ziteng Gao, Limin Wang, Zhifeng Li, and Gangshan Wu. Boundary-aware cascade networks for temporal action segmentation. In ECCV, 2020." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 421, + 287, + 464 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 421, + 287, + 464 + ], + "spans": [ + { + "bbox": [ + 49, + 421, + 287, + 464 + ], + "type": "text", + "content": "[41] Dongxu Wei, Xiaowei Xu, Haibin Shen, and Kejie Huang. Gac-gan: A general method for appearance-controllable human video motion transfer. IEEE Transactions on Multimedia, 23:2457-2470, 2020." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 466, + 287, + 520 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 466, + 287, + 520 + ], + "spans": [ + { + "bbox": [ + 49, + 466, + 287, + 520 + ], + "type": "text", + "content": "[42] Di Wu, Junjun Chen, Nabin Sharma, Shirui Pan, Guodong Long, and Michael Blumenstein. Adversarial action data augmentation for similar gesture action recognition. In 2019 International Joint Conference on Neural Networks (IJCNN), pages 1-8. IEEE, 2019." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 522, + 287, + 553 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 522, + 287, + 553 + ], + "spans": [ + { + "bbox": [ + 49, + 522, + 287, + 553 + ], + "type": "text", + "content": "[43] Fangqiu Yi, Hongyu Wen, and Tingting Jiang. AS-Former: Transformer for action segmentation. CoRR, arXiv 2110.08568, 2021." + } + ] + } + ], + "index": 10 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "text", + "content": "13514" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/0636ab48-f4a3-4a28-9365-8ed3c11dca4b_content_list.json b/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/0636ab48-f4a3-4a28-9365-8ed3c11dca4b_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..9b523f0aff4521ec2aaa158631e09b315e36828d --- /dev/null +++ b/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/0636ab48-f4a3-4a28-9365-8ed3c11dca4b_content_list.json @@ -0,0 +1,2302 @@ +[ + { + "type": "text", + "text": "MasQCLIP for Open-Vocabulary Universal Image Segmentation", + "text_level": 1, + "bbox": [ + 158, + 130, + 813, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Xin $\\mathrm{Xu}^{1*}$ , Tianyi $\\mathrm{Xiong}^{2*}$ , Zheng $\\mathrm{Ding}^3$ , and Zhuowen $\\mathrm{Tu}^3$", + "bbox": [ + 251, + 191, + 718, + 212 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1Peking University", + "bbox": [ + 408, + 223, + 560, + 241 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{2}$ Tsinghua University", + "bbox": [ + 398, + 241, + 568, + 258 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "3University of California, San Diego", + "bbox": [ + 341, + 258, + 629, + 277 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 321, + 313, + 338 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "We present a new method for open-vocabulary universal image segmentation, which is capable of performing instance, semantic, and panoptic segmentation under a unified framework. Our approach, called MasQCLIP, seamlessly integrates with a pre-trained CLIP model by utilizing its dense features, thereby circumventing the need for extensive parameter training. MasQCLIP emphasizes two new aspects when building an image segmentation method with a CLIP model: 1) a student-teacher module to deal with masks of the novel (unseen) classes by distilling information from the base (seen) classes; 2) a fine-tuning process to update model parameters for the queries $Q$ within the CLIP model. Thanks to these two simple and intuitive designs, MasQCLIP is able to achieve state-of-the-art performances with a substantial gain over the competing methods by a large margin across all three tasks, including open-vocabulary instance, semantic, and panoptic segmentation. Project page is at https://masqclip.github.io/.", + "bbox": [ + 75, + 354, + 473, + 627 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 652, + 209, + 669 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "By being universal and open-world, the traditional image segmentation methods that have been mainly trained in a supervised manner can be made less specific and more powerful. When an image segmentation method is open-world, it means that it can handle new concepts with novel classes or categories that are not labeled in its supervised training data. However, this is not something that can be achieved by the algorithm alone, as information about the novel classes that go beyond supervised labels cannot be generated out of thin air. Fortunately, the CLIP models [31] are trained on millions of image-text pairs, which provides a rich source of combinatorial object/scene information by mapping images and texts into the same semantic space.", + "bbox": [ + 75, + 679, + 468, + 876 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/8a117942400126da50eea6613d51923129d0ebb32b65ada22476d0eba2c993e1.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 521, + 320, + 635, + 392 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/315e1c785e7a16abeba1a14d1455f93f6562aecdd3b37845a2c5a4ae5eccd95f.jpg", + "image_caption": [ + "Mask AP50 on COCO Split" + ], + "image_footnote": [], + "bbox": [ + 522, + 396, + 635, + 468 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/2220f69fbd09bb6c62a784be26762ce5ddcd2137d3095f430200475ca9950a69.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 640, + 321, + 751, + 392 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/9346a82e2d2e27c90aadd778c0fbdd0bf7fa6c65cf6440732b1eaef6b34e05ce.jpg", + "image_caption": [ + "mIoU on ADE20k" + ], + "image_footnote": [], + "bbox": [ + 642, + 393, + 754, + 463 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/36527c69802f632a96a027de3a1a417299e760ac78347d0a9d6078363c29eef4.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 754, + 321, + 864, + 391 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/3dd716ce9f3e6670a7c0682d0bec0fe23724404cd3c9a2fe1ad6a78b7bab5ddc.jpg", + "image_caption": [ + "PQ on ADE20k" + ], + "image_footnote": [], + "bbox": [ + 756, + 393, + 854, + 462 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/95273bac1d60a4d9164d3f13a2bc6a5fb7c2a72a2211bac682038faabda24a05.jpg", + "image_caption": [ + "Figure 1: We present the visualization and quantitative results of MasQCLIP on open-vocabulary segmentation with a universal model architecture. As shown, we achieve state-of-the-art performances across three segmentation tasks." + ], + "image_footnote": [], + "bbox": [ + 578, + 494, + 635, + 505 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/e51e0a63327320e81b59e65038a6449476ec62250b223e106b0cd29bdd29ba15.jpg", + "image_caption": [ + "Model Architecture MaskCLIP Ope", + "XPM" + ], + "image_footnote": [], + "bbox": [ + 746, + 494, + 764, + 505 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "As CLIP models are trained contrastively at the global image-text level, they do not directly output segmentation maps at the pixel or region level. Recent works [9, 13, 55] demonstrate the feasibility of adopting and locking a pretrained CLIP model for open-vocabulary image segmentation by adopting a two-stage approach, which first generates class-agnostic mask proposals and subsequently classifies each mask region based on a CLIP model.", + "bbox": [ + 496, + 595, + 890, + 715 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "This decoupled two-stage design, involving localization and then classification, is considered advantageous for open-vocabulary universal segmentation. First, it does not depend on any task specificity. Recent works [7, 8] have attempted to unify instance, semantic, and panoptic segmentation through Transformer-based architectures [6], and the CLIP-based region classification module itself is directly applicable to different types of masks (instance/semantic). Second, it is a natural choice to utilize CLIP models exclusively for object/scene classification rather than localization. The reason is that the dense features within a CLIP visual encoder only carry semantic information, but can-", + "bbox": [ + 496, + 719, + 892, + 900 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Equal Contribution.", + "bbox": [ + 94, + 886, + 209, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "887", + "bbox": [ + 485, + 944, + 511, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "not discriminate between different objects belonging to the same category.", + "bbox": [ + 76, + 90, + 468, + 121 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "However, recent works [9, 20] still exhibit limitations with regard to being open-world. Specifically, the class-agnostic mask proposal network is trained only on the supervision of a limited set of base classes, which restricts its ability to generate mask proposals beyond supervision. Hence, the model performance is hindered when dealing with novel or unseen categories. In addition, although previous works have attempted to introduce some additional modules for mask classification, they fail to fully bridge the gap between image-level and region-level representation, thus lacking in adaptation to mask classification. The balance between maintaining generalization for more categories and adapting CLIP models for mask classification tasks needs further exploration.", + "bbox": [ + 75, + 121, + 468, + 332 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this paper, we aim to conquer these weaknesses. We introduce a new approach called MasQCLIP that can perform open-vocabulary instance, semantic, and panoptic segmentation under a single framework. To accomplish this, MasQCLIP uses a similar two-stage model design: 1) a mask generator stage that extracts object/scene masks, and 2) an encoder-only module that performs mask classification. We are also inspired by the Mask Class Token strategy from MaskCLIP [9], which is tightly integrated with a given CLIP model. MasQCLIP is different from MaskCLIP [9] in two key areas: 1) the use of a student-teacher self-training module that significantly enhances the generation of novel class masks, and 2) fine-tuning the query parameters in the CLIP visual encoder, which better adapts the CLIP models for mask region representations. The following are the contributions of our work:", + "bbox": [ + 75, + 332, + 470, + 574 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We develop MasQCLIP for open-vocabulary universal image segmentation that demonstrates substantial performance improvement over the current state-of-the-art methods by a large margin across all three tasks including open-vocabulary instance, semantic, and panoptic segmentation.", + "- We design a progressive distillation process to generate more novel mask proposals beyond supervision, thus taking a step forward toward open-world mask generation.", + "- We propose a parameter-efficient fine-tuning strategy, MasQ-Tuning, which only tunes the query parameters. When coupled with Mask Class Tokens, MasQ-Tuning is able to preserve the generalization of a pre-trained image-level CLIP model while greatly enhancing its adaptation for segmentation tasks." + ], + "bbox": [ + 94, + 580, + 468, + 828 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 76, + 844, + 218, + 859 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Being universal Traditional image segmentation methods can be roughly divided into three groups: 1) instance seg", + "bbox": [ + 76, + 869, + 468, + 902 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "mentation [14], 2) semantic segmentation [36, 39], and 3) panoptic segmentation [22, 40]. Panoptic segmentation essentially integrates instance and semantic segmentation, but a careful algorithm design is needed [22, 45] to achieve the goal, as instance segmentation is object-centered whereas semantic segmentation is per-pixel based. The introduction and adaptation of Transformers [41] to the object detection task, Detection Transformers [6], also makes the unification of instance and semantic segmentation feasible. In particular, the Mask2Former method [7] unifies background stuff and foreground things under the query token representation by designing a Transformer-based architecture for closed-set universal image segmentation.", + "bbox": [ + 496, + 90, + 890, + 287 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Being open-world Since it is a relatively new topic, there lacks a commonly accepted definition for being \"open-world\". There exists different terms such as zero-shot [3], open-set [19], and open-vocabulary [50]. It is gradually accepted that the open-vocabulary setting has the best alignment with the general open-world expectation where the target of interest to be extracted can be freely specified using a natural language description during inference.", + "bbox": [ + 496, + 297, + 890, + 420 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Open-Vocabulary Detection and Segmentation Various open-vocabulary vision algorithms have been developed. A rough summary for the comparison of existing methods can be seen in [9]. Broadly speaking, there exist methods for open-vocabulary object detection [5, 13, 24, 49, 50], instance segmentation [13, 18], semantic segmentation [12, 23, 46, 58], and panoptic segmentation [9]. Previous works [27, 30, 35, 44, 49, 55] mainly focus on knowledge distillation from an existing CLIP model, but our method integrates CLIP models rather than performing distillation from CLIP models. Some recent works [32, 58] have also attempted to extract dense features from CLIP models to represent pixelwise features.", + "bbox": [ + 496, + 428, + 890, + 623 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Knowledge Distillation Knowledge Distillation [17] has been proposed to extract knowledge from the teacher model to the student model. It is called self-distillation [52] when both teacher and student models adopt the same model architecture. For the image segmentation task, self-training with pseudo labels has been proposed to improve the quality of predicted masks in self-supervised learning [28, 43] and semi-supervised learning [42, 47, 48]. We use a similar strategy but focus on self-distilling novel mask proposals from the teacher model.", + "bbox": [ + 496, + 633, + 890, + 785 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Fine-tuning Fine-tuning aims to efficiently utilize knowledge from large models for downstream tasks. In terms of ConvNet [15, 37], many fine-tuning strategies have been proposed, including bias tuning [4], side tuning [51], and residual adapter [33]. After Transformer [41] is introduced into the field of computer vision, several fine-tuning methods have been proposed for ViT [10]. Recent works have", + "bbox": [ + 496, + 794, + 890, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "888", + "bbox": [ + 485, + 945, + 509, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/286be5ea722844ac01a391d1554ced57959d95b3c34a691e1d2f2d426a5c0e78.jpg", + "image_caption": [ + "Figure 2: Overview of MasQCLIP. MasQCLIP consists of a class-agnostic mask proposal network and a mask classification module based on CLIP. In the mask proposal network, we apply progressive distillation to segment masks beyond base classes. Please refer to Fig. 3 for more details. After we obtain an open-world mask proposal network, the predicted masks are then sent to the classification module to obtain labels. To efficiently utilize the dense CLIP features, we propose MasQ-Tuning. We set new query projections $f_{Q}^{\\prime}$ for the Mask Class Tokens to obtain optimal attention weights, and $f_{Q}^{\\prime}$ at each layer are the only learnable parameters." + ], + "image_footnote": [], + "bbox": [ + 122, + 93, + 846, + 290 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "explored subspace training [16] for low-dimensional reparameterization and prompt tuning [21, 34] for adaptation. In terms of CLIP models, [38, 53] insert adapters into pretrained CLIP models, and DenseCLIP [32] uses CLIP parameters as initialization for segmentation tasks. However, existing works mainly make use of the pre-trained models for a specific dataset, and they do not fully exploit the intrinsic generalization ability in pre-trained models.", + "bbox": [ + 75, + 386, + 472, + 508 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Preliminary", + "text_level": 1, + "bbox": [ + 76, + 540, + 204, + 556 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "MaskCLIP [9] adapts the CLIP model for segmentation tasks through a two-stage pipeline. Specifically, a class-agnostic mask proposal network first generates candidate masks, then MaskCLIP utilizes dense CLIP features to classify each mask proposal with a corresponding Mask Class Token. Mask Class Tokens are initialized with the class token in the CLIP visual encoder, then are appended alongside the original CLIP tokens (image tokens and a class token). Mask Class Tokens extract features from CLIP tokens through the masked cross-attention mechanism where mask proposals also serve as attention masks, i.e.,", + "bbox": [ + 75, + 571, + 468, + 738 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {C r o s s A t t n} (\\cdot) = \\operatorname {s o f t m a x} \\left(Q _ {\\text {m a s k}} K _ {\\text {i m g}} ^ {T} + \\mathcal {M} _ {\\text {m a s k}}\\right) \\cdot V _ {\\text {i m g}}, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 84, + 761, + 467, + 779 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nQ _ {\\text {m a s k}}, K _ {\\text {i m g}}, V _ {\\text {i m g}} = f _ {Q} \\left(x _ {\\text {m a s k}}\\right), f _ {K} \\left(x _ {\\text {i m g}}\\right), f _ {V} \\left(x _ {\\text {i m g}}\\right). \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 94, + 782, + 468, + 800 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Here, $x_{\\mathrm{mask}} \\in \\mathbb{R}^{m \\times C}$ , $x_{\\mathrm{img}} \\in \\mathbb{R}^{p \\times C}$ denote $m$ Mask Class Tokens and $p$ CLIP tokens respectively, and $f_{Q}, f_{K}, f_{V}$ denote the projections for query, key, and value respectively. In MaskCLIP, $f_{Q}, f_{K}, f_{V}$ are frozen to maintain generalization. The attention mask $\\mathcal{M}_{\\mathrm{mask}} \\in \\mathbb{R}^{m \\times p}$ is derived as", + "bbox": [ + 75, + 823, + 468, + 900 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {M} _ {\\text {m a s k}} (i, j) = \\left\\{ \\begin{array}{l l} 0 & \\text {i f i - t h m a s k f a l l s i n j - t h p a t c h} \\\\ - \\infty & \\text {o t h e r w i s e} \\end{array} . \\right. \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 511, + 417, + 890, + 470 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The final classification scores are the dot product between Mask Class Tokens and the language descriptors from the CLIP language encoder.", + "bbox": [ + 498, + 474, + 890, + 520 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4. Methods", + "text_level": 1, + "bbox": [ + 500, + 545, + 598, + 560 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4.1. Problem Setting", + "text_level": 1, + "bbox": [ + 500, + 574, + 661, + 590 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "During training, the model is only provided with a set of images and their annotations on base classes $C_B$ . We denote the training dataset as $\\mathcal{D}_B = \\{(I_i, \\mathcal{Y}_i)\\}_{i=1}^N$ . Each annotation $\\mathcal{Y}_i$ contains ground-truth masks $\\mathcal{Y}_i^M$ and their labels $\\mathcal{Y}_i^L$ on base classes in image $I_i$ . In the inference stage, we evaluate our model on another set of images with a new set of novel classes $C_N$ , and the testing dataset is denoted as $\\mathcal{D}_N$ . According to the relationship between $\\mathcal{D}_B$ and $\\mathcal{D}_N$ , previous works mainly use two settings:", + "bbox": [ + 496, + 601, + 890, + 738 + ], + "page_idx": 2 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- Cross-dataset. $\\mathcal{D}_B$ and $\\mathcal{D}_N$ are different datasets, and class sets $C_B$ and $C_N$ may overlap.", + "- Base-novel. $C_B$ and $C_N$ are disjoint, i.e., $C_B \\cap C_N = \\varnothing$ . Under this setting, the same dataset, such as COCO [25], is used during training and testing." + ], + "bbox": [ + 517, + 758, + 890, + 848 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In our paper, we evaluate our proposed algorithm on both of the above settings.", + "bbox": [ + 500, + 869, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "889", + "bbox": [ + 485, + 945, + 509, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/e49f49ec6be19ff7cf4257afd6fc71beabf1f2a0feeb73371f184289ae8c6f5d.jpg", + "image_caption": [ + "Figure 3: Detailed interpretation of progressive distillation. We select high-quality mask proposals with novel concepts from the inference results of the teacher model as extra annotations. These extra annotations are then distilled into the student model to encourage generalization. This process is performed iteratively." + ], + "image_footnote": [], + "bbox": [ + 107, + 88, + 436, + 224 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.2. Proposed Method", + "text_level": 1, + "bbox": [ + 76, + 318, + 250, + 334 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.2.1 Progressive Distillation for Mask Generation", + "text_level": 1, + "bbox": [ + 76, + 343, + 442, + 358 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Object Score. In experiments, we observe that MaskCLIP [9] does not consistently assign higher confidence to mask proposals that align more accurately with ground-truth masks. Therefore, we incorporate a binary classification head to the class-agnostic mask proposal network in our MasQCLIP. The resulting object score, denoted as $p_{\\mathrm{obj}} \\in \\mathbb{R}$ , estimates the quality of mask proposals. During inference, the final classification score for the $i$ -th class is determined by $p_{\\mathrm{cls}}^{(i)} = p_{\\mathrm{obj}} \\cdot p_{\\mathrm{clip}}^{(i)}$ . Here, $p_{\\mathrm{clip}}^{(i)}$ represents the score for the $i$ -th class obtained from the mask classification module, which will be further discussed in Sec. 4.2.2.", + "bbox": [ + 75, + 369, + 468, + 536 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "If training is conducted with annotations from both base classes $C_B$ and novel classes $C_N$ , the object score can serve as a general indicator of mask quality. However, when supervision is only provided on $C_B$ , the object score is more reflective of the quality of base masks, leading to bias toward $C_B$ . But we will show in Sec. 5.4.1 that incorporating object scores still boosts performance on both $C_B$ and $C_N$ by a clear margin. Hence, it is still reasonable and effective to incorporate object scores for all mask proposals.", + "bbox": [ + 75, + 539, + 468, + 675 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Progressive Distillation. To develop an open-world mask proposal network capable of generating masks beyond base classes $C_B$ , we propose a progressive distillation strategy. By utilizing the object score as an indicator of mask quality, we can filter high-quality mask proposals that do not overlap with mask annotations of $C_B$ , thus producing extra annotations for training. By iteratively repeating this distillation process, the network will be able to segment more concepts progressively and eventually be open-world.", + "bbox": [ + 75, + 686, + 468, + 823 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Specifically, we initialize the teacher model $\\mathcal{T}_{\\mu}$ with the mask proposal network trained on the base annotations $\\mathcal{D}_B^{\\prime} = \\{(I_i,\\mathcal{Y}_i^M)\\}_{i = 1}^N$ without class labels. To produce extra supervision for the student model $\\mathcal{T}_{\\theta}$ on image $I_{i}$ , we first obtain inference result $\\mathcal{T}_{\\mu}(I_i)$ from the teacher model.", + "bbox": [ + 76, + 824, + 468, + 902 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "algorithm", + "code_caption": [], + "code_body": "Algorithm 1 Progressive Distillation \nRequire: Initial teacher model $\\mathcal{T}_{\\mu}$ with parameter $\\mu$ \nRequire: Dataset $\\mathcal{D}_B' = \\{(I_i, \\mathcal{Y}_i^M)\\}_{i=1}^N$ (only masks) \nRequire: Score threshold $\\alpha$ , IoU threshold $\\beta$ \nfor $K$ iterations do \n $\\theta \\gets \\mu$ ▷ Initialize the student model $\\mathcal{T}_{\\theta}$ \nfor $(I_i, \\mathcal{Y}_i^M)$ in $\\mathcal{D}_B'$ do \n $\\mathcal{Y} \\gets \\mathcal{Y}_i^M$ ▷ $\\mathcal{Y}$ : supervision for $\\mathcal{T}_{\\theta}$ $\\hat{\\mathcal{Y}} = \\mathcal{T}_{\\mu}(I_i)$ \nfor $\\hat{y}$ in $\\hat{\\mathcal{Y}}$ do \nif $\\forall y \\in \\mathcal{Y}, IoU(\\hat{y}, y) < \\beta$ then \nif score( $\\hat{y}$ ) > $\\alpha$ then \n $\\mathcal{Y} \\gets \\mathcal{Y} \\cup \\{\\hat{y}\\}$ $L_{\\theta} = \\mathcal{L}(\\mathcal{T}_{\\theta}(I_i), \\mathcal{Y})$ $\\theta \\gets \\theta - \\gamma \\nabla_{\\theta}(L_{\\theta})$ $\\mu \\gets \\theta$ ▷ Update the teacher model $\\mathcal{T}_{\\mu}$", + "bbox": [ + 500, + 90, + 890, + 349 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Then we select mask proposals with high object scores that are non-overlap with ground-truth masks in $\\mathcal{Y}_i^M$ . These selected masks are considered novel masks and combined with $\\mathcal{Y}_i^M$ to form the supervision $\\mathcal{V}$ for the student model. To further boost generalization, we train the student model progressively by updating the parameters of the student model to the teacher model iteratively. A more detailed algorithm is presented in Alg. 1. Experiments show that our algorithm works surprisingly well.", + "bbox": [ + 496, + 386, + 890, + 522 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.2.2 MasQ-Tuning", + "text_level": 1, + "bbox": [ + 500, + 553, + 651, + 568 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Given masks produced by the class-agnostic mask proposal network, we expect to classify each mask region using pretrained CLIP models. To maintain the generalization ability of CLIP models, MaskCLIP [9] freezes all CLIP parameters and appends auxiliary tokens for region classification. According to Eq. (1), for each Mask Class Token $x_{\\mathrm{mask}}^{(i)} \\in \\mathbb{R}^C$ , we have its query embedding $q_i = f_Q(x_{\\mathrm{mask}}^{(i)})$ and attention weight over $p$ CLIP tokens, $\\text{softmax}(q_i K_{\\mathrm{img}}^T + \\mathcal{M}_i) \\in \\mathbb{R}^p$ . The attention weight indicates $x_{\\mathrm{mask}}^{(i)}$ where to focus, and $V_{\\mathrm{img}}$ is interpreted as the dense CLIP features that all Mask Class Tokens can extract.", + "bbox": [ + 496, + 584, + 890, + 760 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "MaskCLIP preserves the original feature space of CLIP by freezing all parameters, however, it lacks in adaption. Although the appended Mask Class Tokens perform classification similar to the class token in CLIP, there is still a shift between them. Specifically, each Mask Class Token is intended to classify a mask region in an image, while the original class token is designed to extract image-level feature. To enhance adaptation ability, we propose applying new query projections $f_{Q}^{\\prime}$ to each cross-attention layer for", + "bbox": [ + 496, + 763, + 890, + 902 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "890", + "bbox": [ + 485, + 945, + 509, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Mask Class Tokens, i.e.,", + "bbox": [ + 76, + 90, + 240, + 104 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {C r o s s A t t n} (\\cdot) = \\operatorname {s o f t m a x} \\left(\\mathbf {Q} _ {\\text {m a s k}} ^ {\\prime} K _ {\\text {i m g}} ^ {T} + \\mathcal {M} _ {\\text {m a s k}}\\right) \\cdot V _ {\\text {i m g}}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 84, + 114, + 467, + 133 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {Q} _ {\\text {m a s k}} ^ {\\prime}, K _ {\\text {i m g}}, V _ {\\text {i m g}} = \\mathbf {f} _ {\\mathbf {Q}} ^ {\\prime} \\left(x _ {\\text {m a s k}}\\right), f _ {K} \\left(x _ {\\text {i m g}}\\right), f _ {V} \\left(x _ {\\text {i m g}}\\right). \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 96, + 137, + 467, + 154 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In this way, Mask Class Tokens obtain better attention weights through learning. In addition, since the softmax operator in Eq. (4) serves as a normalizer, the results of Eq. (4) still lie in the sub-space spanned by rows of $V_{\\mathrm{img}}$ . $V_{\\mathrm{img}}$ is projected from CLIP tokens and thus preserves the knowledge of CLIP. Therefore, MasQ-Tuning is able to improve adaptation while maintaining generalization.", + "bbox": [ + 76, + 164, + 467, + 268 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To effectively inherit the knowledge and the statistics of CLIP, other layers (layernorm, FFN, and the final projection) are frozen during fine-tuning.", + "bbox": [ + 76, + 270, + 467, + 315 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Losses. Our goal is to match the appended Mask Class Tokens with their corresponding ground-truth labels, so we use the dot-product between Mask Class Tokens and language descriptors as scores and compute cross-entropy loss, i.e.,", + "bbox": [ + 76, + 318, + 467, + 378 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {c l s}} = - \\log \\left(\\frac {\\exp \\left(s _ {y}\\right)}{\\sum_ {i} \\exp \\left(s _ {i}\\right)}\\right). \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 169, + 388, + 467, + 422 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $s_i$ denotes the score for $i$ -th class and $y$ is the assigned label for the mask. If a predicted mask is matched to a ground-truth mask according to an IoU threshold, we then assign the mask a label. Otherwise, we use a fixed word, \"background\", as the label for the predicted mask.", + "bbox": [ + 76, + 430, + 467, + 505 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 76, + 518, + 207, + 535 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We evaluate MasQCLIP on three segmentation tasks to demonstrate its effectiveness and universality, and we follow the commonly-used settings in different segmentation tasks. For instance segmentation, we use base-novel setting following [18]. For semantic and panoptic segmentation, we use cross-dataset setting following [9, 13]. We show MasQCLIP achieves state-of-the-art results on all benchmarks with a universal architecture. We also conduct ablation studies to verify our proposed method.", + "bbox": [ + 76, + 544, + 467, + 679 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.1. Datasets and Evaluation Metrics", + "text_level": 1, + "bbox": [ + 76, + 691, + 362, + 707 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "COCO. In base-novel setting, we use instance segmentation annotations of COCO [25]. Following [18], we partition COCO annotations into 48 base classes for training and 17 novel classes for evaluation. There are 108k training images and 5k validation images. In cross-dataset setting, we use panoptic segmentation [22] annotations of COCO for training, which include 80 thing classes (foreground) and 53 stuff classes (background). There are 118k training images and 5k validation images.", + "bbox": [ + 76, + 715, + 467, + 851 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "ADE20k. ADE20k [56, 57] serves for semantic segmentation and panoptic segmentation evaluation under cross-dataset setting. There are 2k validation images in total. The", + "bbox": [ + 76, + 854, + 467, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "full version (A-847) includes 847 classes and the short version (A-150) includes 150 classes.", + "bbox": [ + 498, + 90, + 888, + 119 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "PASCAL-Context. Pascal-Context [29] serves for semantic segmentation evaluation under cross-dataset setting. There are 5k validation images in total. The full version (P-459) includes 459 classes and the short version (P-59) includes 59 classes.", + "bbox": [ + 498, + 125, + 890, + 199 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Evaluation Metrics. For instance segmentation, we report $mAP$ (mean average precision) [25] at IoU (intersection-over-union) of 0.5 following base-novel setting [1, 18, 50]. For semantic segmentation, we report $mIoU$ (mean intersection-over-union) [11] for evaluation. For panoptic segmentation, we report $PQ$ (panoptic quality) [22].", + "bbox": [ + 498, + 204, + 890, + 295 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.2. Implementation Details", + "text_level": 1, + "bbox": [ + 500, + 306, + 715, + 323 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Class-Agnostic Mask Proposal Network. We train Mask2Former [7] or Mask R-CNN [14] with ResNet-50 backbone to generate class-agnostic mask proposals. The labels of masks are not used as supervision, and the number of mask proposals for each image is set to 100 for both models. In Mask2Former, the number of classes is set to 1 to obtain the object score. In Mask R-CNN, we adopt the confidence scores of the RPN head as object scores. The default experiment setting for Mask R-CNN is R50-FPN-1x.", + "bbox": [ + 498, + 330, + 890, + 465 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Progressive Distillation. For Mask2Former, we first train the initial teacher model until convergence. Then, we retrain the student model for 2 rounds with 30k iterations each round (under both settings). Unless stated, other experiment settings are set to default as training Mask2Former [7]. For Mask R-CNN, we use the checkpoint of R50-FPN-1x as the initial teacher model. We then re-train the student model for 2 rounds with 10k iterations each round (under both settings). For all models and settings, we set the threshold of object scores $\\alpha$ to 0.8, and the NMS threshold $\\beta$ to 0.1.", + "bbox": [ + 498, + 470, + 890, + 621 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "MasQ-Tuning. During fine-tuning, we use the same CLIP model ViT-L/14@336px as in [9]. The language descriptors are simply the text embeddings of category names given by the language encoder of CLIP without any prompt. The number of Mask Class Tokens is set to 100 which is equivalent to the number of mask proposals. The query projection $f_{Q}^{\\prime}$ at each layer exhibits the same architecture of a linear projection as the original $f_{Q}$ in CLIP visual encoder. In both cross-dataset and base-novel settings, we use AdamW [26] as our default optimizer and the initial learning rate is set to 0.0001. We assign a predicted mask a label if it has an IoU higher than 0.6 with a ground-truth mask. We fine-tune for 10k iterations with a batch size of 4, and the learning rate is decreased by a factor of 10 at 9k iterations. During inference, the post-processing follows Mask2Former after obtaining labels for mask proposals.", + "bbox": [ + 498, + 625, + 890, + 867 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Settings. For each model architecture (Mask R-CNN or Mask2Former), we train two MasQCLIP models for base-", + "bbox": [ + 500, + 869, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "891", + "bbox": [ + 485, + 945, + 508, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/d78c5f656a96dfa12235597a431cbb76bd30aaad80c08989ef1d6348de5aa241.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodsBackboneInstanceSemanticPanoptic
BaseNovelAllA-150A-847P-59P-459PQ\\( PQ^{th} \\)\\( PQ^{st} \\)
XPM [18]ResNet-5041.521.636.3-------
LSeg+ [23]EffNet-B7---18.03.846.57.8---
OpenSeg [12]EffNet-B7---21.16.342.19.0---
MaskCLIP (Mask R-CNN) [9]ResNet-50---22.46.841.39.112.911.216.1
MaskCLIP (Mask2Former) [9]ResNet-50---23.78.245.910.015.113.518.3
MasQCLIP (Mask R-CNN)ResNet-5040.728.437.523.78.444.414.114.914.515.6
MasQCLIP (Mask2Former)ResNet-5051.031.946.030.410.757.818.223.321.227.7
+9.5+10.3+9.7+6.7+2.5+11.3+8.2+8.2+7.7+9.4
", + "bbox": [ + 83, + 87, + 883, + 227 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/69449e0ab9a0972b238a6c8ed9ad0328164ba539937d087b5254cfb2d7c51d2d.jpg", + "table_caption": [ + "Table 1: Results on open-vocabulary universal image segmentation. We compare MasQCLIP with state-of-the-art models on three segmentation tasks with a universal architecture. We use Mask R-CNN or Mask2Former as our class-agnostic mask proposal network. All methods in the table rely only on COCO dataset for training. a) For instance segmentation, we report mask AP50 following base-novel setting [18]. b) For semantic segmentation, we report mIoU on ADE20k and PASCAL-Context following cross-dataset setting [20]. A-150 and A-847 represent ADE20k with 150 classes and 847 classes respectively. P-59 and P-459 represent PASCAL-Context with 59 classes and 459 classes respectively. c) For panoptic segmentation, we report $PQ$ on ADE20k following cross-dataset setting [9]. We achieve significant improvements on all evaluation metrics." + ], + "table_footnote": [], + "table_body": "
MethodsConstrainedGeneralized
BaseNovelBaseNovelAll
OVR [50]42.020.941.617.135.2
SB [1]41.620.841.016.034.5
BA-RPN [54]41.820.141.315.434.5
OVR+OMP [2]31.314.130.58.324.7
XPM [18]42.424.041.521.636.3
MasQCLIP (Mask R-CNN)40.930.140.728.437.5
MasQCLIP (Mask2Former)51.234.351.031.946.0
", + "bbox": [ + 83, + 345, + 459, + 457 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2: Results on open-vocabulary instance segmentation. We report mask AP50 in the table. The results presented in the table all use the ResNet-50 backbone. Constrained setting means that the model is evaluated on either base classes or novel classes separately. Generalized setting means that the model is tested jointly on both base and novel classes. Notice that the results of novel classes show the generalization ability of models.", + "bbox": [ + 75, + 460, + 468, + 559 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "novel and cross-dataset settings separately. The former model is trained on base classes of COCO-instance dataset and is tested on novel classes (for instance segmentation), while the latter is trained on the COCO-panoptic dataset and is used for both semantic (through post-possessing) and panoptic segmentation evaluation.", + "bbox": [ + 75, + 579, + 468, + 672 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.3. Main Results", + "text_level": 1, + "bbox": [ + 76, + 680, + 215, + 695 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Instance Segmentation. We evaluate our MasQCLIP on instance segmentation under base-novel setting. We first train MasQCLIP on base classes of COCO-instance dataset and then evaluate the model on novel classes. The detailed results are presented in Tab. 2. As shown, when using Mask R-CNN as our class-agnostic mask proposal network, we achieve an improvement of 6.8 AP50 on novel classes over XPM [18]. When using Mask2Former, we further achieve an improvement of 10.3 AP50. The evaluation metrics on novel classes mainly reflect the generalization ability of models. Since our relative improvement on novel classes is much higher than that on base classes across two mask proposal networks, our proposed method enjoys better gen", + "bbox": [ + 75, + 703, + 470, + 902 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "eralization ability compared to previous works.", + "bbox": [ + 498, + 349, + 812, + 364 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Semantic Segmentation. We evaluate our MasQCLIP on semantic segmentation under cross-dataset setting. We directly use the model trained on COCO-panoptic dataset for evaluation, and report the results on ADE20ksemantic and PASCAL-Context-semantic datasets in Tab. 1. In terms of $mIoU$ , MasQCLIP improves previous state-of-the-art results by 6.7, 2.5, 11.3, and 8.2 on A-150, A-847, P-59, and P-459 datasets respectively.", + "bbox": [ + 496, + 368, + 890, + 489 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Panoptic Segmentation. We evaluate our MasQCLIP on panoptic segmentation under cross-dataset setting. We first train MasQCLIP on COCO-panoptic dataset, and then directly evaluate the model on ADE20k-panoptic dataset. The results are presented in Tab. 1. As shown, when using the same mask proposal network architecture, MasQCLIP outperforms state-of-the-art MaskCLIP [9] by $8.2PQ$ . Even adopted with a weaker mask proposal network of Mask R-CNN, MasQCLIP still achieves on-par results on $PQ$ compared with MaskCLIP.", + "bbox": [ + 496, + 493, + 892, + 643 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.4. Ablation Studies", + "text_level": 1, + "bbox": [ + 500, + 652, + 663, + 667 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.4.1 Progressive Distillation", + "text_level": 1, + "bbox": [ + 500, + 676, + 714, + 691 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this section, we conduct ablation studies on progressive distillation. We evaluate the models on instance segmentation under base-novel setting. The initial teacher model is trained for 100k iterations on base annotations, and the student model is then re-trained for 30k iterations each round using the initial teacher model.", + "bbox": [ + 496, + 700, + 890, + 790 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Object Scores. We first study the importance of object scores. As shown in Tab. 3, incorporating object scores boosts performance on base classes and novel classes significantly. In addition, despite object scores being trained only on base classes, they still serve as reliable indicators of mask quality for novel classes, which demonstrates the generalization of object scores. The results show that it is", + "bbox": [ + 496, + 794, + 892, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "892", + "bbox": [ + 485, + 945, + 509, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/313b2598d8e2a93ef81219129097882bc911056c80d7f9e561f337e1827356ea.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 150, + 88, + 315, + 185 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/e0a89c9733dc265e7db936459ae396452221a8c27c925d77f123b0e9c59fc333.jpg", + "image_caption": [ + "Input" + ], + "image_footnote": [], + "bbox": [ + 150, + 186, + 315, + 268 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/54317b5d8c1e37f4a15068dca94d6f7e13f44ebcf8154bf3f679c8596757d0f4.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 316, + 88, + 480, + 185 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/3208962849aacd0762c7b8e43731159c023146899a265dad3b439e528045c51d.jpg", + "image_caption": [ + "CLIP Baseline", + "Figure 4: Comparison on open-vocabulary instance segmentation. We evaluate on the same set of images as in MaskCLIP [9]. The above two images are from ADE20k dataset. Visualization results show that our mask proposals are more robust and high-quality." + ], + "image_footnote": [], + "bbox": [ + 316, + 186, + 480, + 268 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/572f3d55c09644ae6cd336af6ac07b736837baf2c4874ebe1959c08ed61ff70b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 482, + 88, + 647, + 185 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/9034916a48c684023c3344336d5543641ddbb23bc8173796a8d551336229689d.jpg", + "image_caption": [ + "MaskCLIP" + ], + "image_footnote": [], + "bbox": [ + 482, + 186, + 647, + 268 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/2e780436b55f5dacb84bf19b4ff34962246516e3544187e181bc99d60a18b2d9.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 651, + 88, + 816, + 185 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/85ac3f211955747f2d606f5a8df7bcea7ef09ca40c580bfcc77655624680a025.jpg", + "image_caption": [ + "MasQCLIP" + ], + "image_footnote": [], + "bbox": [ + 651, + 186, + 815, + 268 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/f86d4390dfdfe0327925a621c68241159b083ca99dc9b2fa176482a077595263.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ModelsScoresBaseNovelAll
Mask2Former-16.911.315.4
Mask2Former✓53.822.645.6
", + "bbox": [ + 120, + 335, + 426, + 380 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/0a73c7feae376aad2471b912355d04111b35e06b27cd1988a08d8985452a488e.jpg", + "table_caption": [ + "Table 3: Ablations on Object Scores. We report mask AP50 in the table. Models denote the architecture of class-agnostic mask proposal networks. Scores denote whether we incorporate object scores." + ], + "table_footnote": [], + "table_body": "
TeacherStudentBaseNovelAll
100k-53.822.645.6
100k30k×150.626.144.2
100k30k×251.031.946.0
100k30k×351.231.246.0
200k-54.718.245.1
", + "bbox": [ + 133, + 446, + 413, + 534 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "reasonable to consider object scores as a general indicator of mask quality.", + "bbox": [ + 75, + 625, + 468, + 655 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Iterative Re-training. Tab. 4 shows the effectiveness of progressive distillation. After we train the student model for 2 rounds progressively, the model performance improves on novel classes by 9.3 AP50. Although the results manifest a slight performance drop on base classes, it can be explained that the model is balancing between the base and extra (novel) annotations, thus leading the model to be less overfitted on base classes.", + "bbox": [ + 75, + 657, + 468, + 777 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "If we continue to train the student model for more rounds (e.g. 3 rounds), the model does not gain further improvement in generalization ability, indicating that there might exist an upper bound for the progressive distillation process. In addition, we also show that the improvement on novel classes cannot simply gain from a longer training schedule. When training the network for another 100k iterations without progressive distillation, there is a notable performance", + "bbox": [ + 75, + 779, + 470, + 901 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/f6cd14320b0babf03e8417f71d716fbaf2dc9d4e8a89a4f03c64ac23ea0192a6.jpg", + "table_caption": [ + "Table 4: Ablations on Iterative Re-training. We report mask AP50 in the table. We adopt the Mask2Former architecture and incorporate object scores by default. Teacher denotes the training iterations of the initial teacher model, and Student denotes how we train the student model progressively." + ], + "table_footnote": [], + "table_body": "
MethodsQKVAllParamADE20kCOCO
PQmIoUPQmIoU
Freeze-----10.715.719.422.1
Tune-V--✓-25M14.418.050.063.2
Tune-QKV✓✓✓-75M14.918.650.563.5
Tune-CLIP✓✓✓✓304M14.718.349.063.6
Tune-K-✓--25M22.529.848.361.6
Tune-QK✓✓--50M22.930.149.062.3
Tune-Q (ours)✓---25M23.330.448.562.0
", + "bbox": [ + 503, + 335, + 893, + 438 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 5: Ablations on MasQ-Tuning. We try different fine-tuning strategies. $Q, K, V$ means the newly added query, key, and value projections for Mask Class Tokens respectively, and All means all the newly added parameters (also including layernorm, FFN, and the final projection). Param denotes the total number of trainable parameters. The models are first trained on COCO and then evaluated on ADE20k. We note that the metrics on ADE20k mainly show the generalization ability.", + "bbox": [ + 496, + 443, + 893, + 555 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "drop of 4.4 AP50 (from 22.6 to 18.2) on novel classes. Our observation supports that improvement of model performance indeed comes from progressive distillation.", + "bbox": [ + 496, + 571, + 890, + 617 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.4.2 MasQ-Tuning", + "text_level": 1, + "bbox": [ + 500, + 631, + 651, + 646 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "To validate our fine-tuning method, MasQ-Tuning, we build several baselines to prove its effectiveness.", + "bbox": [ + 496, + 655, + 890, + 686 + ], + "page_idx": 6 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- Freeze: Same as the MaskCLIP w/o RMA baseline in [9]. We incorporate object scores during inference.", + "- Tune-Q: Only query projections $f_{Q}^{\\prime}$ for Mask Class Tokens are learnable during fine-tuning. Notice that MasQCLIP adopts this fine-tuning strategy.", + "- Tune-K: Only key projections $f_{K}^{\\prime}$ for Mask Class Tokens are learnable during fine-tuning.", + "- Tune-V: Only value projections $f_V'$ for Mask Class Tokens are learnable during fine-tuning.", + "- Tune-QK: Query and key projections for Mask Class Tokens ( $f_{Q}^{\\prime}$ and $f_{K}^{\\prime}$ ), are learnable during fine-tuning.", + "- Tune-QKV: Query, key, and value projections for Mask" + ], + "bbox": [ + 517, + 700, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "893", + "bbox": [ + 485, + 945, + 509, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/29e008b61647159925c30af0ffcc4d05b79eb02dd04c4bdccf4cb4b71dccc4e9.jpg", + "image_caption": [ + "Image" + ], + "image_footnote": [], + "bbox": [ + 148, + 87, + 282, + 167 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/c9ee995dd2f5f6cd624bc90b42f9c8795fd83b747eb8b1c1d655b73ced7394a3.jpg", + "image_caption": [ + "GT" + ], + "image_footnote": [], + "bbox": [ + 282, + 88, + 416, + 166 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/422cac3ac5120310d831aa4bb764aedc65d05a7e53068950b0f06290d41666ef.jpg", + "image_caption": [ + "house" + ], + "image_footnote": [], + "bbox": [ + 223, + 184, + 253, + 205 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/ed4b982c7f9fefc00ff85cb98088f945140039c89882a4c38735aa4f66417545.jpg", + "image_caption": [ + "sky" + ], + "image_footnote": [], + "bbox": [ + 263, + 185, + 290, + 205 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/49d16f5694885bde193c79b80dea69cf70b010cd617cf4fa43322100ca33c03e.jpg", + "image_caption": [ + "grass" + ], + "image_footnote": [], + "bbox": [ + 338, + 185, + 364, + 205 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/3c2f713d9f68e5ab6f0e1e8f31fb6f2656fd4268153f2952262a1cf7b912a135.jpg", + "image_caption": [ + "land" + ], + "image_footnote": [], + "bbox": [ + 374, + 185, + 411, + 205 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/31aebb737ea92b16ef61f274aefa707f46dd53e5ee69a417188e38d8f1912c95.jpg", + "image_caption": [ + "OpenSeg" + ], + "image_footnote": [], + "bbox": [ + 418, + 89, + 550, + 166 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/c62cfde2fdd1b598da2edb3d8e9bdaa2d327f5111dd905ee30a085df749e0c51.jpg", + "image_caption": [ + "tree" + ], + "image_footnote": [], + "bbox": [ + 413, + 185, + 447, + 205 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/14c9ed297be81d46341daade677991558b74bd8fa70f8538ff260f73bfd733ed.jpg", + "image_caption": [ + "brick" + ], + "image_footnote": [], + "bbox": [ + 450, + 185, + 478, + 205 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/4767cb8d94d69026d060968c9e94fbdad6e1875cd20f7a9a07ce64f282666896.jpg", + "image_caption": [ + "ock" + ], + "image_footnote": [], + "bbox": [ + 496, + 185, + 532, + 205 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/dae54618c3189131fa900dd38c9e3c11a70ac4964b8bc16101c92cfba907e167.jpg", + "image_caption": [ + "river" + ], + "image_footnote": [], + "bbox": [ + 524, + 185, + 550, + 205 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/5a6ffaf4dc89589dc4117b50e80f759f33865dcb0be9887b9b1d99843fe8af41.jpg", + "image_caption": [ + "MaskCLIP" + ], + "image_footnote": [], + "bbox": [ + 553, + 89, + 684, + 166 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/90077c89a02487a4c495d86a97598ae827e51329031f219f73eecee02dd4980b.jpg", + "image_caption": [ + "wall" + ], + "image_footnote": [], + "bbox": [ + 553, + 185, + 589, + 205 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/9aae7d2abfecf5281161ab17e99d0b777f0bda5d5c7dfc7050930dc2d0d2501e.jpg", + "image_caption": [ + "building" + ], + "image_footnote": [], + "bbox": [ + 594, + 185, + 637, + 205 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "", + "bbox": [ + 661, + 89, + 684, + 166 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/983d8498e627fdbb9ab465ed7b2474086d52a205df4853d91058b4432c7ed43d.jpg", + "image_caption": [ + "roo" + ], + "image_footnote": [], + "bbox": [ + 661, + 185, + 696, + 205 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/da3d4621a4abc798c79151be251343545a3a1620ca1b6dcd21390e1be7fd8580.jpg", + "image_caption": [ + "MasQCLIP" + ], + "image_footnote": [], + "bbox": [ + 689, + 89, + 821, + 166 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/97928c55d8cbe9b776bb180a205e23042a648defae7a248d86f12ab8d450c640.jpg", + "image_caption": [ + "window" + ], + "image_footnote": [], + "bbox": [ + 689, + 185, + 736, + 205 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/b7307c8780ef94a70b5d463f3e2f98eb823853f7020cfd1845f69a477d00bc82.jpg", + "image_caption": [ + "Figure 5: Comparison on open-vocabulary semantic segmentation. We evaluate on the same image as in OpenSeg [12]. Notice that MasQCLIP successfully recognizes the windows on the house, demonstrating that MasQCLIP is able to classify small objects." + ], + "image_footnote": [], + "bbox": [ + 196, + 267, + 424, + 372 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/9e906a0338cc8efe347b91a36e14765fe17f0f1ec960b13b55f13c21b44e47ae.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 196, + 373, + 421, + 477 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/ffa5867664025190cee55d6cffde3d2da2df1f17a30f53280ab23a538d2a0180.jpg", + "image_caption": [ + "Figure 6: Comparison on open-vocabulary panoptic segmentation. We evaluate on the same set of images as in MaskCLIP [9]. The images are from ADE20k dataset. Visualization shows that MasQCLIP produces higher-quality masks and has higher classification accuracy." + ], + "image_footnote": [], + "bbox": [ + 196, + 478, + 421, + 582 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/a6f63e171f507d10239d612c33d0af68ef693e49a6b25c2756a25f53341fd716.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 424, + 268, + 593, + 372 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/0227ced23a31af289f392e852ec6a923c8f1c0cefb42f78262fced6834a68dfd.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 426, + 373, + 593, + 477 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/8a47267291f7bd91033207411f1ac4af2377f3ca3ea25165ed7c34e704ca6267.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 426, + 478, + 593, + 582 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/8e52a2530dd8eb1afbd2cecb51224354601da450001b90d343da26bbe5347c39.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 596, + 268, + 776, + 372 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/a8ff2ddb5dbce34e240090c2876274c780440a8d6069df6d3f172d213c6bbcb4.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 596, + 373, + 776, + 477 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/c222dbd78a250ae4ab504af02fa7aaa676cff9c4d67813d2a1da150e1e64526b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 596, + 478, + 774, + 582 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Class Tokens $(f_{Q}^{\\prime}, f_{K}^{\\prime}$ , and $f_{V}^{\\prime}$ ), are learnable during fine-tuning.", + "bbox": [ + 107, + 652, + 468, + 683 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "- Tune-CLIP: A new set of CLIP parameters is learned during fine-tuning, and masked-cross attention is performed between Mask Class Tokens and CLIP tokens. We use CLIP parameters as initialization.", + "bbox": [ + 94, + 686, + 468, + 748 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this ablation study, we test the models on semantic and panoptic segmentation under cross-dataset setting. We use the same class-agnostic mask proposal network for all models, and then fine-tune the mask classification module based on the predicted masks. Training settings are all kept the same. Our results are shown in Tab. 5.", + "bbox": [ + 75, + 760, + 468, + 851 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Adaptation. We compare the evaluation metrics of the above methods on COCO dataset to show the strong adaptation ability of MasQ-Tuning. Compared to Freeze with 19.4", + "bbox": [ + 75, + 854, + 468, + 901 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "$PQ$ and 22.1 mIoU on COCO, Tune-Q has a significant improvement of 29.1 $PQ$ (from 19.4 to 48.5) and 39.9 mIoU (from 22.1 to 62.0) respectively. This shows that the improvement on adaptation ability should be credited to those learnable query projections $f_{Q}^{\\prime}$ for Mask Class Tokens. In addition, compared to Tune-CLIP with 49.0 $PQ$ and 63.6 mIoU on COCO, Tune-Q has much fewer learnable parameters, but only has little performance drop (-0.5 $PQ$ and -1.6 mIoU). This indicates that simply adding more parameters is not helpful, and our proposed MasQ-Tuning has achieved impressive adaptation ability.", + "bbox": [ + 496, + 652, + 893, + 819 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Generalization. We now focus on the performance of the above methods on ADE20k dataset to show the strong generalization ability of MasQ-Tuning. When adding learnable value projections $f_V'$ for Mask Class Tokens, the model cannot generalize well to ADE20k dataset. Compared to", + "bbox": [ + 496, + 824, + 893, + 902 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "894", + "bbox": [ + 485, + 944, + 511, + 955 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/5fa77b82f5b728cdfc8c9d9dc1ad6ee25ef98f5cd221d30d859a7f1c47c1c0e2.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 192, + 88, + 410, + 185 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/180b1eefdf780a8db901004209e282444b0d65137219005fedfedd22caca7c57.jpg", + "image_caption": [ + "(a) \"a black cat\", \"an orange cat\"" + ], + "image_footnote": [], + "bbox": [ + 191, + 186, + 411, + 282 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/e8b4b26ec7b8039f10ff1713e81154076fc8ba049fc4afef8f79f78d39a0a462.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 416, + 88, + 581, + 186 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/f06f9eb282f5a372a7680567b9af3f746863c1168ac85846a392a6a0ad5fa12f.jpg", + "image_caption": [ + "(b) \"beer\", \"wine\"", + "Figure 7: User-specified segmentation. We use the model trained on COCO-panoptic for evaluation. Visualization results show that our model can distinguish subtle differences among objects." + ], + "image_footnote": [], + "bbox": [ + 416, + 186, + 581, + 282 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/07a0426558e65ae0c540d3e5498ca62d395a5db31f364e99cb6f56e5db4574e5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 588, + 88, + 774, + 186 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/9b6e5755d00e48243b8ad56079806a8689750bb777bb6573a2f37fd5e91d92b2.jpg", + "image_caption": [ + "(c) \"an adult\", \"a child\"" + ], + "image_footnote": [], + "bbox": [ + 588, + 186, + 774, + 282 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Tune-Q with 23.3 PQ, Tune-V, Tune-QKV and Tune-CLIP have a performance drop of 8.9, 8.4, and 8.6 on $PQ$ respectively. This proves the importance of freezing $V_{\\mathrm{img}}$ which is interpreted as dense CLIP features. By inheriting $V_{\\mathrm{img}}$ from the CLIP model, MasQCLIP is able to preserve the original feature space within CLIP. Compared to Tune-QK, Tune-Q reaches better performance on ADE20k and is more parameter-efficient, where only $8.2\\%$ of original parameters in CLIP visual encoder are added for training. Therefore, we choose Tune-Q as the fine-tuning strategy of MasQCLIP.", + "bbox": [ + 75, + 359, + 468, + 511 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5.5. Qualitative Results", + "text_level": 1, + "bbox": [ + 76, + 527, + 259, + 544 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this section, we compare the visualization results of MasQCLIP with previous models [9, 12]. The results of instance, semantic, and panoptic segmentation are presented in Fig. 4, Fig. 5, and Fig. 6 respectively. For a fair comparison, We all use the same set of images as previous works [9, 12]. We observe from the visualization results that MasQCLIP produces more robust mask proposals and enjoys a higher mask classification accuracy, which corresponds to our two key components proposed in MasQCLIP. As shown in Fig. 7, MasQCLIP exhibits the ability to segment objects of arbitrary classes as per user specifications and to discriminate between subtle distinctions within them (e.g. \"beer\" vs. \"wine\", \"child\" vs. \"adult\").", + "bbox": [ + 75, + 554, + 468, + 750 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5.6. Efficiency", + "text_level": 1, + "bbox": [ + 76, + 768, + 189, + 785 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "MasQCLIP exhibits great capability in open-vocabulary universal segmentation while being computationally efficient at the same time. We report the results of GFLOPs in Tab. 6. As shown, the GFLOPs of MasQCLIP is only $14.5\\%$ higher than the combined GFLOPs of Mask2Former and CLIP visual encoder, and is $34.1\\%$ lower than the GFLOPs of MaskCLIP.", + "bbox": [ + 75, + 794, + 468, + 898 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/7291a5a25faf002548be67ee98b96014c6aac1daf74059c0c726af45abb7595b.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ModelsGFLOPs
Mask2Former [7]78.9
CLIP Visual Encoder [31]233.0
MaskCLIP† [9]542.0
MasQCLIP (ours)357.2
", + "bbox": [ + 568, + 356, + 820, + 429 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 6: Model efficiency. The resolution of input images is set to $640 \\times 640$ for Mask2Former and $336 \\times 336$ for CLIP Visual Encoder. We use the CLIP model ViT-L/14@336px. $\\dagger$ means our re-implement according to the paper (no public codes available).", + "bbox": [ + 498, + 434, + 893, + 491 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Conclusions", + "text_level": 1, + "bbox": [ + 500, + 508, + 625, + 525 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We propose a two-stage model, MasQCLIP, for open-vocabulary universal segmentation. We first design a progressive distillation process for the class-agnostic mask proposal network to segment open-world masks. Additionally, we adapt CLIP models for mask (region) classification while maintaining the generalization ability of CLIP through our proposed MasQ-Tuning method. We achieve state-of-the-art results with substantial improvement over the existing approaches across three open-vocabulary tasks including instance, semantic, and panoptic segmentation.", + "bbox": [ + 496, + 535, + 890, + 686 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Limitations. Since MasQCLIP is built on top of a pretrained CLIP model, though fine-tuning is introduced, the performance of our model is nevertheless largely decided by the generalization ability of the CLIP model. Another limitation of our method is that mask proposals are generated by a fixed network (once pre-trained), which might limit its capability for object types of arbitrary specification.", + "bbox": [ + 496, + 690, + 890, + 797 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement. This work is supported by NSF Award IIS-2127544.", + "bbox": [ + 500, + 800, + 890, + 829 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 500, + 845, + 596, + 861 + ], + "page_idx": 8 + }, + { + "type": "ref_text", + "text": "[1] Ankan Bansal, Karan Sikka, Gaurav Sharma, Rama Chellappa, and Ajay Divakaran. Zero-shot object detection. In", + "bbox": [ + 506, + 872, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "895", + "bbox": [ + 485, + 945, + 509, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Proceedings of the European Conference on Computer Vision, pages 384-400, 2018. 5, 6", + "[2] David Biertimpel, Sindi Shkodrani, Anil S Baslamisli, and Nóra Baka. Prior to segment: Foreground cues for weakly annotated classes in partially supervised instance segmentation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2824-2833, 2021. 6", + "[3] Maxime Bucher, Tuan-Hung Vu, Matthieu Cord, and Patrick Pérez. Zero-shot semantic segmentation. Advances in Neural Information Processing Systems, 32, 2019. 2", + "[4] Han Cai, Chuang Gan, Ligeng Zhu, and Song Han. Tinytl: Reduce memory, not parameters for efficient on-device learning. Advances in Neural Information Processing Systems, 33:11285-11297, 2020. 2", + "[5] Zhaowei Cai, Gukyeong Kwon, Avinash Ravichandran, Erhan Bas, Zhuowen Tu, Rahul Bhotika, and Stefano Soatto. X-detr: A versatile architecture for instance-wise vision-language tasks. arXiv preprint arXiv:2204.05626, 2022. 2", + "[6] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Proceedings of the European Conference on Computer Vision, pages 213-229. Springer, 2020. 1, 2", + "[7] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1290–1299, 2022. 1, 2, 5, 9", + "[8] Bowen Cheng, Alex Schwing, and Alexander Kirillov. Per-pixel classification is not all you need for semantic segmentation. Advances in Neural Information Processing Systems, 34:17864-17875, 2021. 1", + "[9] Zheng Ding, Jieke Wang, and Zhuowen Tu. Open-vocabulary universal image segmentation with maskclip. In International Conference on Machine Learning, 2023. 1, 2, 3, 4, 5, 6, 7, 8, 9", + "[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2020. 2", + "[11] Mark Everingham, SM Eslami, Luc Van Gool, Christopher KI Williams, John Winn, and Andrew Zisserman. The Pascal visual object classes challenge: A retrospective. International Journal of Computer Vision, 111(1):98-136, 2015. 5", + "[12] Golnaz Ghiasi, Xiuye Gu, Yin Cui, and Tsung-Yi Lin. Scaling open-vocabulary image segmentation with image-level labels. In Proceedings of the European Conference on Computer Vision, pages 540-557. Springer, 2022. 2, 6, 8, 9", + "[13] Xiuye Gu, Tsung-Yi Lin, Weicheng Kuo, and Yin Cui. Open-vocabulary object detection via vision and language knowledge distillation. In International Conference on Learning Representations, 2022. 1, 2, 5", + "[14] Kaiming He, Georgia Gkioxari, Piotr Dólar, and Ross Girshick. Mask r-cnn. In Proceedings of the IEEE International" + ], + "bbox": [ + 78, + 92, + 470, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Conference on Computer Vision, pages 2961-2969, 2017. 2, 5", + "[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016. 2", + "[16] Xuehai He, Chunyuan Li, Pengchuan Zhang, Jianwei Yang, and Xin Eric Wang. Parameter-efficient fine-tuning for vision transformers. arXiv preprint arXiv:2203.16329, 2022. 3", + "[17] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, et al. Distilling the knowledge in a neural network. arXiv preprint arXiv:1503.02531, 2015. 2", + "[18] Dat Huynh, Jason Kuen, Zhe Lin, Jiumiang Gu, and Ehsan Elhamifar. Open-vocabulary instance segmentation via robust cross-modal pseudo-labeling. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7020-7031, 2022. 2, 5, 6", + "[19] Jaedong Hwang, Seoung Wug Oh, Joon-Young Lee, and Bohyung Han. Exemplar-based open-set panoptic segmentation network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1175–1184, 2021. 2", + "[20] Chao Jia, Yinfei Yang, Ye Xia, Yi-Ting Chen, Zarana Parekh, Hieu Pham, Quoc Le, Yun-Hsuan Sung, Zhen Li, and Tom Duerig. Scaling up visual and vision-language representation learning with noisy text supervision. In International Conference on Machine Learning, pages 4904-4916, 2021. 2, 6", + "[21] Menglin Jia, Luming Tang, Bor-Chun Chen, Claire Cardie, Serge Belongie, Bharath Hariharan, and Ser-Nam Lim. Visual prompt tuning. In Proceedings of the European Conference on Computer Vision, pages 709-727. Springer, 2022. 3", + "[22] Alexander Kirillov, Kaiming He, Ross Girshick, Carsten Rother, and Piotr Dollar. Panoptic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9404-9413, 2019. 2, 5", + "[23] Boyi Li, Kilian Q Weinberger, Serge Belongie, Vladlen Koltun, and René Ranftl. Language-driven semantic segmentation. In International Conference on Learning Representations, 2022. 2, 6", + "[24] Liunian Harold Li, Pengchuan Zhang, Haotian Zhang, Jianwei Yang, Chunyuan Li, Yiwu Zhong, Lijuan Wang, Lu Yuan, Lei Zhang, Jenq-Neng Hwang, et al. Grounded language-image pre-training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10965-10975, 2022. 2", + "[25] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In Proceedings of the European Conference on Computer Vision, pages 740-755. Springer, 2014. 3, 5", + "[26] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In International Conference on Learning Representations, 2018. 5", + "[27] Huaishao Luo, Lei Ji, Ming Zhong, Yang Chen, Wen Lei, Nan Duan, and Tianrui Li. Clip4clip: An empirical study" + ], + "bbox": [ + 503, + 92, + 890, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "896", + "bbox": [ + 486, + 945, + 511, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "of clip for end to end video clip retrieval. arXiv preprint arXiv:2104.08860, 2021. 2", + "[28] Luke Melas-Kyriazi, Christian Rupprecht, Iro Laina, and Andrea Vedaldi. Deep spectral methods: A surprisingly strong baseline for unsupervised semantic segmentation and localization. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8364-8375, 2022. 2", + "[29] Roozbeh Mottaghi, Xianjie Chen, Xiaobai Liu, Nam-Gyu Cho, Seong-Whan Lee, Sanja Fidler, Raquel Urtasun, and Alan Yuille. The role of context for object detection and semantic segmentation in the wild. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 891–898, 2014. 5", + "[30] Or Patashnik, Zongze Wu, Eli Shechtman, Daniel Cohen-Or, and Dani Lischinski. Styleclip: Text-driven manipulation of stylegan imagery. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2085–2094, 2021. 2", + "[31] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning, pages 8748-8763. PMLR, 2021. 1, 9", + "[32] Yongming Rao, Wenliang Zhao, Guangyi Chen, Yansong Tang, Zheng Zhu, Guan Huang, Jie Zhou, and Jiwen Lu. Denseclip: Language-guided dense prediction with context-aware prompting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18082-18091, 2022. 2, 3", + "[33] Sylvestre-Alvise Rebuffi, Hakan Bilen, and Andrea Vedaldi. Learning multiple visual domains with residual adapters. Advances in Neural Information Processing Systems, 30, 2017. 2", + "[34] Mark Sandler, Andrey Zhmoginov, Max Vlademyrov, and Andrew Jackson. Fine-tuning image transformers using learnable memory. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12155-12164, 2022. 3", + "[35] Sheng Shen, Liunian Harold Li, Hao Tan, Mohit Bansal, Anna Rohrbach, Kai-Wei Chang, Zhewei Yao, and Kurt Keutzer. How much can clip benefit vision-and-language tasks? In International Conference on Learning Representations, 2022. 2", + "[36] Jamie Shotton, John Winn, Carsten Rother, and Antonio Criminisi. Textonboost: Joint appearance, shape and context modeling for multi-class object recognition and segmentation. In Proceedings of the European Conference on Computer Vision, pages 1-15. Springer, 2006. 2", + "[37] Karen Simonyan and Andrew Zisserman. Very deep convolutional networks for large-scale image recognition. arXiv preprint arXiv:1409.1556, 2014. 2", + "[38] Yi-Lin Sung, Jaemin Cho, and Mohit Bansal. VI-adapter: Parameter-efficient transfer learning for vision-and-language tasks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5227-5237, 2022. 3" + ], + "bbox": [ + 78, + 90, + 470, + 898 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[39] Zhuowen Tu. Auto-context and its application to high-level vision tasks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1-8. IEEE, 2008. 2", + "[40] Zhuowen Tu, Xiangrong Chen, Alan L Yuille, and Song-Chun Zhu. Image parsing: Unifying segmentation, detection, and recognition. International Journal of Computer Vision, 63(2):113-140, 2005. 2", + "[41] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in Neural Information Processing Systems, 30, 2017. 2", + "[42] Weiyao Wang, Matt Feiszli, Heng Wang, Jitendra Malik, and Du Tran. Open-world instance segmentation: Exploiting pseudo ground truth from learned pairwise affinity. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4422-4432, 2022. 2", + "[43] Xinlong Wang, Zhiding Yu, Shalini De Mello, Jan Kautz, Anima Anandkumar, Chunhua Shen, and Jose M Alvarez. Freesolo: Learning to segment objects without annotations. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14176-14186, 2022. 2", + "[44] Zhecan Wang, Noel Codella, Yen-Chun Chen, Luowei Zhou, Jianwei Yang, Xiyang Dai, Bin Xiao, Haoxuan You, Shih-Fu Chang, and Lu Yuan. Clip-td: Clip targeted distillation for vision-language tasks. arXiv preprint arXiv:2201.05729, 2022. 2", + "[45] Yuwen Xiong, Renjie Liao, Hengshuang Zhao, Rui Hu, Min Bai, Ersin Yumer, and Raquel Urtasun. Upsnet: A unified panoptic segmentation network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. 2", + "[46] Mengde Xu, Zheng Zhang, Fangyun Wei, Yutong Lin, Yue Cao, Han Hu, and Xiang Bai. A simple baseline for open-vocabulary semantic segmentation with pre-trained vision-language model. In Proceedings of the European Conference on Computer Vision, pages 736-753. Springer, 2022. 2", + "[47] Lihe Yang, Wei Zhuo, Lei Qi, Yinghuan Shi, and Yang Gao. St++: Make self-training work better for semi-supervised semantic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4268-4277, 2022. 2", + "[48] Jianlong Yuan, Yifan Liu, Chunhua Shen, Zhibin Wang, and Hao Li. A simple baseline for semi-supervised semantic segmentation with strong data augmentation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 8229-8238, 2021. 2", + "[49] Yuhang Zang, Wei Li, Kaiyang Zhou, Chen Huang, and Chen Change Loy. Open-vocabulary detr with conditional matching. In Proceedings of the European Conference on Computer Vision, pages 106-122, 2022. 2", + "[50] Alireza Zareian, Kevin Dela Rosa, Derek Hao Hu, and Shih-Fu Chang. Open-vocabulary object detection using captions. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14393-14402, 2021. 2, 5, 6" + ], + "bbox": [ + 501, + 92, + 890, + 898 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "897", + "bbox": [ + 486, + 945, + 509, + 955 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[51] Jeffrey O Zhang, Alexander Sax, Amir Zamir, Leonidas Guibas, and Jitendra Malik. Side-tuning: a baseline for network adaptation via additive side networks. In Proceedings of the European Conference on Computer Vision, pages 698-714. Springer, 2020. 2", + "[52] Linfeng Zhang, Jiebo Song, Anni Gao, Jingwei Chen, Chenglong Bao, and Kaisheng Ma. Be your own teacher: Improve the performance of convolutional neural networks via self distillation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 3713-3722, 2019. 2", + "[53] Renrui Zhang, Rongyao Fang, Wei Zhang, Peng Gao, Kunchang Li, Jifeng Dai, Yu Qiao, and Hongsheng Li. Tip-adapter: Training-free clip-adapter for better vision-language modeling. arXiv preprint arXiv:2111.03930, 2021. 3", + "[54] Ye Zheng, Jiahong Wu, Yongqiang Qin, Faen Zhang, and Li Cui. Zero-shot instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2593-2602, 2021. 6", + "[55] Yiwu Zhong, Jianwei Yang, Pengchuan Zhang, Chunyuan Li, Noel Codella, Liunian Harold Li, Luowei Zhou, Xiyang Dai, Lu Yuan, Yin Li, and Jianfeng Gao. Regionclip: Region-based language-image pretraining. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 16793-16803, 2022. 1, 2", + "[56] Bolei Zhou, Hang Zhao, Xavier Puig, Sanja Fidler, Adela Barriuso, and Antonio Torralba. Scene parsing through ade20k dataset. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 633-641, 2017. 5", + "[57] Bolei Zhou, Hang Zhao, Xavier Puig, Tete Xiao, Sanja Fidler, Adela Barriuso, and Antonio Torralba. Semantic understanding of scenes through the ade20k dataset. International Journal of Computer Vision, 127(3):302-321, 2019. 5", + "[58] Chong Zhou, Chen Change Loy, and Bo Dai. Extract free dense labels from clip. In Proceedings of the European Conference on Computer Vision, pages 696-712. Springer, 2022. 2" + ], + "bbox": [ + 78, + 90, + 470, + 625 + ], + "page_idx": 11 + }, + { + "type": "page_number", + "text": "898", + "bbox": [ + 486, + 945, + 509, + 955 + ], + "page_idx": 11 + } +] \ No newline at end of file diff --git a/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/0636ab48-f4a3-4a28-9365-8ed3c11dca4b_model.json b/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/0636ab48-f4a3-4a28-9365-8ed3c11dca4b_model.json new file mode 100644 index 0000000000000000000000000000000000000000..19ec0ed1f55e8fa97b4ed91f581adbc65387a1cb --- /dev/null +++ b/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/0636ab48-f4a3-4a28-9365-8ed3c11dca4b_model.json @@ -0,0 +1,3227 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.159, + 0.131, + 0.815, + 0.154 + ], + "angle": 0, + "content": "MasQCLIP for Open-Vocabulary Universal Image Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.252, + 0.193, + 0.719, + 0.213 + ], + "angle": 0, + "content": "Xin \\(\\mathrm{Xu}^{1*}\\), Tianyi \\(\\mathrm{Xiong}^{2*}\\), Zheng \\(\\mathrm{Ding}^3\\), and Zhuowen \\(\\mathrm{Tu}^3\\)" + }, + { + "type": "text", + "bbox": [ + 0.409, + 0.224, + 0.562, + 0.242 + ], + "angle": 0, + "content": "1Peking University" + }, + { + "type": "text", + "bbox": [ + 0.4, + 0.242, + 0.57, + 0.26 + ], + "angle": 0, + "content": "\\(^{2}\\)Tsinghua University" + }, + { + "type": "text", + "bbox": [ + 0.342, + 0.26, + 0.63, + 0.278 + ], + "angle": 0, + "content": "3University of California, San Diego" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.323, + 0.314, + 0.339 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.355, + 0.474, + 0.628 + ], + "angle": 0, + "content": "We present a new method for open-vocabulary universal image segmentation, which is capable of performing instance, semantic, and panoptic segmentation under a unified framework. Our approach, called MasQCLIP, seamlessly integrates with a pre-trained CLIP model by utilizing its dense features, thereby circumventing the need for extensive parameter training. MasQCLIP emphasizes two new aspects when building an image segmentation method with a CLIP model: 1) a student-teacher module to deal with masks of the novel (unseen) classes by distilling information from the base (seen) classes; 2) a fine-tuning process to update model parameters for the queries \\( Q \\) within the CLIP model. Thanks to these two simple and intuitive designs, MasQCLIP is able to achieve state-of-the-art performances with a substantial gain over the competing methods by a large margin across all three tasks, including open-vocabulary instance, semantic, and panoptic segmentation. Project page is at https://masqclip.github.io/." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.654, + 0.21, + 0.67 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.68, + 0.47, + 0.877 + ], + "angle": 0, + "content": "By being universal and open-world, the traditional image segmentation methods that have been mainly trained in a supervised manner can be made less specific and more powerful. When an image segmentation method is open-world, it means that it can handle new concepts with novel classes or categories that are not labeled in its supervised training data. However, this is not something that can be achieved by the algorithm alone, as information about the novel classes that go beyond supervised labels cannot be generated out of thin air. Fortunately, the CLIP models [31] are trained on millions of image-text pairs, which provides a rich source of combinatorial object/scene information by mapping images and texts into the same semantic space." + }, + { + "type": "image", + "bbox": [ + 0.522, + 0.321, + 0.637, + 0.393 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.523, + 0.397, + 0.636, + 0.469 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.527, + 0.47, + 0.634, + 0.48 + ], + "angle": 0, + "content": "Mask AP50 on COCO Split" + }, + { + "type": "image", + "bbox": [ + 0.642, + 0.322, + 0.752, + 0.393 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.643, + 0.395, + 0.755, + 0.464 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.662, + 0.47, + 0.733, + 0.479 + ], + "angle": 0, + "content": "mIoU on ADE20k" + }, + { + "type": "image", + "bbox": [ + 0.756, + 0.322, + 0.866, + 0.392 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.757, + 0.395, + 0.855, + 0.463 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.776, + 0.47, + 0.837, + 0.479 + ], + "angle": 0, + "content": "PQ on ADE20k" + }, + { + "type": "image", + "bbox": [ + 0.579, + 0.496, + 0.636, + 0.506 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.656, + 0.484, + 0.745, + 0.506 + ], + "angle": 0, + "content": "Model Architecture MaskCLIP Ope" + }, + { + "type": "image", + "bbox": [ + 0.747, + 0.496, + 0.765, + 0.506 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.768, + 0.496, + 0.814, + 0.506 + ], + "angle": 0, + "content": "XPM" + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.514, + 0.895, + 0.571 + ], + "angle": 0, + "content": "Figure 1: We present the visualization and quantitative results of MasQCLIP on open-vocabulary segmentation with a universal model architecture. As shown, we achieve state-of-the-art performances across three segmentation tasks." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.596, + 0.892, + 0.716 + ], + "angle": 0, + "content": "As CLIP models are trained contrastively at the global image-text level, they do not directly output segmentation maps at the pixel or region level. Recent works [9, 13, 55] demonstrate the feasibility of adopting and locking a pretrained CLIP model for open-vocabulary image segmentation by adopting a two-stage approach, which first generates class-agnostic mask proposals and subsequently classifies each mask region based on a CLIP model." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.893, + 0.901 + ], + "angle": 0, + "content": "This decoupled two-stage design, involving localization and then classification, is considered advantageous for open-vocabulary universal segmentation. First, it does not depend on any task specificity. Recent works [7, 8] have attempted to unify instance, semantic, and panoptic segmentation through Transformer-based architectures [6], and the CLIP-based region classification module itself is directly applicable to different types of masks (instance/semantic). Second, it is a natural choice to utilize CLIP models exclusively for object/scene classification rather than localization. The reason is that the dense features within a CLIP visual encoder only carry semantic information, but can-" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.21, + 0.9 + ], + "angle": 0, + "content": "*Equal Contribution." + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.945, + 0.512, + 0.957 + ], + "angle": 0, + "content": "887" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.122 + ], + "angle": 0, + "content": "not discriminate between different objects belonging to the same category." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.122, + 0.47, + 0.333 + ], + "angle": 0, + "content": "However, recent works [9, 20] still exhibit limitations with regard to being open-world. Specifically, the class-agnostic mask proposal network is trained only on the supervision of a limited set of base classes, which restricts its ability to generate mask proposals beyond supervision. Hence, the model performance is hindered when dealing with novel or unseen categories. In addition, although previous works have attempted to introduce some additional modules for mask classification, they fail to fully bridge the gap between image-level and region-level representation, thus lacking in adaptation to mask classification. The balance between maintaining generalization for more categories and adapting CLIP models for mask classification tasks needs further exploration." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.333, + 0.471, + 0.575 + ], + "angle": 0, + "content": "In this paper, we aim to conquer these weaknesses. We introduce a new approach called MasQCLIP that can perform open-vocabulary instance, semantic, and panoptic segmentation under a single framework. To accomplish this, MasQCLIP uses a similar two-stage model design: 1) a mask generator stage that extracts object/scene masks, and 2) an encoder-only module that performs mask classification. We are also inspired by the Mask Class Token strategy from MaskCLIP [9], which is tightly integrated with a given CLIP model. MasQCLIP is different from MaskCLIP [9] in two key areas: 1) the use of a student-teacher self-training module that significantly enhances the generation of novel class masks, and 2) fine-tuning the query parameters in the CLIP visual encoder, which better adapts the CLIP models for mask region representations. The following are the contributions of our work:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.581, + 0.47, + 0.673 + ], + "angle": 0, + "content": "- We develop MasQCLIP for open-vocabulary universal image segmentation that demonstrates substantial performance improvement over the current state-of-the-art methods by a large margin across all three tasks including open-vocabulary instance, semantic, and panoptic segmentation." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.674, + 0.47, + 0.735 + ], + "angle": 0, + "content": "- We design a progressive distillation process to generate more novel mask proposals beyond supervision, thus taking a step forward toward open-world mask generation." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.737, + 0.47, + 0.829 + ], + "angle": 0, + "content": "- We propose a parameter-efficient fine-tuning strategy, MasQ-Tuning, which only tunes the query parameters. When coupled with Mask Class Tokens, MasQ-Tuning is able to preserve the generalization of a pre-trained image-level CLIP model while greatly enhancing its adaptation for segmentation tasks." + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.581, + 0.47, + 0.829 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.845, + 0.22, + 0.86 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Being universal Traditional image segmentation methods can be roughly divided into three groups: 1) instance seg" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.289 + ], + "angle": 0, + "content": "mentation [14], 2) semantic segmentation [36, 39], and 3) panoptic segmentation [22, 40]. Panoptic segmentation essentially integrates instance and semantic segmentation, but a careful algorithm design is needed [22, 45] to achieve the goal, as instance segmentation is object-centered whereas semantic segmentation is per-pixel based. The introduction and adaptation of Transformers [41] to the object detection task, Detection Transformers [6], also makes the unification of instance and semantic segmentation feasible. In particular, the Mask2Former method [7] unifies background stuff and foreground things under the query token representation by designing a Transformer-based architecture for closed-set universal image segmentation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.298, + 0.892, + 0.421 + ], + "angle": 0, + "content": "Being open-world Since it is a relatively new topic, there lacks a commonly accepted definition for being \"open-world\". There exists different terms such as zero-shot [3], open-set [19], and open-vocabulary [50]. It is gradually accepted that the open-vocabulary setting has the best alignment with the general open-world expectation where the target of interest to be extracted can be freely specified using a natural language description during inference." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.429, + 0.892, + 0.624 + ], + "angle": 0, + "content": "Open-Vocabulary Detection and Segmentation Various open-vocabulary vision algorithms have been developed. A rough summary for the comparison of existing methods can be seen in [9]. Broadly speaking, there exist methods for open-vocabulary object detection [5, 13, 24, 49, 50], instance segmentation [13, 18], semantic segmentation [12, 23, 46, 58], and panoptic segmentation [9]. Previous works [27, 30, 35, 44, 49, 55] mainly focus on knowledge distillation from an existing CLIP model, but our method integrates CLIP models rather than performing distillation from CLIP models. Some recent works [32, 58] have also attempted to extract dense features from CLIP models to represent pixelwise features." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.634, + 0.892, + 0.786 + ], + "angle": 0, + "content": "Knowledge Distillation Knowledge Distillation [17] has been proposed to extract knowledge from the teacher model to the student model. It is called self-distillation [52] when both teacher and student models adopt the same model architecture. For the image segmentation task, self-training with pseudo labels has been proposed to improve the quality of predicted masks in self-supervised learning [28, 43] and semi-supervised learning [42, 47, 48]. We use a similar strategy but focus on self-distilling novel mask proposals from the teacher model." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Fine-tuning Fine-tuning aims to efficiently utilize knowledge from large models for downstream tasks. In terms of ConvNet [15, 37], many fine-tuning strategies have been proposed, including bias tuning [4], side tuning [51], and residual adapter [33]. After Transformer [41] is introduced into the field of computer vision, several fine-tuning methods have been proposed for ViT [10]. Recent works have" + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.946, + 0.511, + 0.956 + ], + "angle": 0, + "content": "888" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.123, + 0.094, + 0.848, + 0.291 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.298, + 0.892, + 0.37 + ], + "angle": 0, + "content": "Figure 2: Overview of MasQCLIP. MasQCLIP consists of a class-agnostic mask proposal network and a mask classification module based on CLIP. In the mask proposal network, we apply progressive distillation to segment masks beyond base classes. Please refer to Fig. 3 for more details. After we obtain an open-world mask proposal network, the predicted masks are then sent to the classification module to obtain labels. To efficiently utilize the dense CLIP features, we propose MasQ-Tuning. We set new query projections \\( f_{Q}^{\\prime} \\) for the Mask Class Tokens to obtain optimal attention weights, and \\( f_{Q}^{\\prime} \\) at each layer are the only learnable parameters." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.387, + 0.473, + 0.509 + ], + "angle": 0, + "content": "explored subspace training [16] for low-dimensional reparameterization and prompt tuning [21, 34] for adaptation. In terms of CLIP models, [38, 53] insert adapters into pretrained CLIP models, and DenseCLIP [32] uses CLIP parameters as initialization for segmentation tasks. However, existing works mainly make use of the pre-trained models for a specific dataset, and they do not fully exploit the intrinsic generalization ability in pre-trained models." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.541, + 0.205, + 0.558 + ], + "angle": 0, + "content": "3. Preliminary" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.572, + 0.47, + 0.739 + ], + "angle": 0, + "content": "MaskCLIP [9] adapts the CLIP model for segmentation tasks through a two-stage pipeline. Specifically, a class-agnostic mask proposal network first generates candidate masks, then MaskCLIP utilizes dense CLIP features to classify each mask proposal with a corresponding Mask Class Token. Mask Class Tokens are initialized with the class token in the CLIP visual encoder, then are appended alongside the original CLIP tokens (image tokens and a class token). Mask Class Tokens extract features from CLIP tokens through the masked cross-attention mechanism where mask proposals also serve as attention masks, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.086, + 0.762, + 0.468, + 0.78 + ], + "angle": 0, + "content": "\\[\n\\operatorname {C r o s s A t t n} (\\cdot) = \\operatorname {s o f t m a x} \\left(Q _ {\\text {m a s k}} K _ {\\text {i m g}} ^ {T} + \\mathcal {M} _ {\\text {m a s k}}\\right) \\cdot V _ {\\text {i m g}}, \\tag {1}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.096, + 0.784, + 0.469, + 0.801 + ], + "angle": 0, + "content": "\\[\nQ _ {\\text {m a s k}}, K _ {\\text {i m g}}, V _ {\\text {i m g}} = f _ {Q} \\left(x _ {\\text {m a s k}}\\right), f _ {K} \\left(x _ {\\text {i m g}}\\right), f _ {V} \\left(x _ {\\text {i m g}}\\right). \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.824, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Here, \\(x_{\\mathrm{mask}} \\in \\mathbb{R}^{m \\times C}\\), \\(x_{\\mathrm{img}} \\in \\mathbb{R}^{p \\times C}\\) denote \\(m\\) Mask Class Tokens and \\(p\\) CLIP tokens respectively, and \\(f_{Q}, f_{K}, f_{V}\\) denote the projections for query, key, and value respectively. In MaskCLIP, \\(f_{Q}, f_{K}, f_{V}\\) are frozen to maintain generalization. The attention mask \\(\\mathcal{M}_{\\mathrm{mask}} \\in \\mathbb{R}^{m \\times p}\\) is derived as" + }, + { + "type": "equation", + "bbox": [ + 0.513, + 0.419, + 0.892, + 0.472 + ], + "angle": 0, + "content": "\\[\n\\mathcal {M} _ {\\text {m a s k}} (i, j) = \\left\\{ \\begin{array}{l l} 0 & \\text {i f i - t h m a s k f a l l s i n j - t h p a t c h} \\\\ - \\infty & \\text {o t h e r w i s e} \\end{array} . \\right. \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.476, + 0.892, + 0.521 + ], + "angle": 0, + "content": "The final classification scores are the dot product between Mask Class Tokens and the language descriptors from the CLIP language encoder." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.546, + 0.599, + 0.561 + ], + "angle": 0, + "content": "4. Methods" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.575, + 0.662, + 0.591 + ], + "angle": 0, + "content": "4.1. Problem Setting" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.602, + 0.892, + 0.739 + ], + "angle": 0, + "content": "During training, the model is only provided with a set of images and their annotations on base classes \\( C_B \\). We denote the training dataset as \\( \\mathcal{D}_B = \\{(I_i, \\mathcal{Y}_i)\\}_{i=1}^N \\). Each annotation \\( \\mathcal{Y}_i \\) contains ground-truth masks \\( \\mathcal{Y}_i^M \\) and their labels \\( \\mathcal{Y}_i^L \\) on base classes in image \\( I_i \\). In the inference stage, we evaluate our model on another set of images with a new set of novel classes \\( C_N \\), and the testing dataset is denoted as \\( \\mathcal{D}_N \\). According to the relationship between \\( \\mathcal{D}_B \\) and \\( \\mathcal{D}_N \\), previous works mainly use two settings:" + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.759, + 0.892, + 0.79 + ], + "angle": 0, + "content": "- Cross-dataset. \\(\\mathcal{D}_B\\) and \\(\\mathcal{D}_N\\) are different datasets, and class sets \\(C_B\\) and \\(C_N\\) may overlap." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.803, + 0.892, + 0.849 + ], + "angle": 0, + "content": "- Base-novel. \\( C_B \\) and \\( C_N \\) are disjoint, i.e., \\( C_B \\cap C_N = \\varnothing \\). Under this setting, the same dataset, such as COCO [25], is used during training and testing." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.759, + 0.892, + 0.849 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "In our paper, we evaluate our proposed algorithm on both of the above settings." + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.946, + 0.511, + 0.957 + ], + "angle": 0, + "content": "889" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.109, + 0.089, + 0.437, + 0.226 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.231, + 0.47, + 0.3 + ], + "angle": 0, + "content": "Figure 3: Detailed interpretation of progressive distillation. We select high-quality mask proposals with novel concepts from the inference results of the teacher model as extra annotations. These extra annotations are then distilled into the student model to encourage generalization. This process is performed iteratively." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.319, + 0.25, + 0.335 + ], + "angle": 0, + "content": "4.2. Proposed Method" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.344, + 0.443, + 0.359 + ], + "angle": 0, + "content": "4.2.1 Progressive Distillation for Mask Generation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.371, + 0.47, + 0.537 + ], + "angle": 0, + "content": "Object Score. In experiments, we observe that MaskCLIP [9] does not consistently assign higher confidence to mask proposals that align more accurately with ground-truth masks. Therefore, we incorporate a binary classification head to the class-agnostic mask proposal network in our MasQCLIP. The resulting object score, denoted as \\( p_{\\mathrm{obj}} \\in \\mathbb{R} \\), estimates the quality of mask proposals. During inference, the final classification score for the \\( i \\)-th class is determined by \\( p_{\\mathrm{cls}}^{(i)} = p_{\\mathrm{obj}} \\cdot p_{\\mathrm{clip}}^{(i)} \\). Here, \\( p_{\\mathrm{clip}}^{(i)} \\) represents the score for the \\( i \\)-th class obtained from the mask classification module, which will be further discussed in Sec. 4.2.2." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.54, + 0.47, + 0.676 + ], + "angle": 0, + "content": "If training is conducted with annotations from both base classes \\( C_B \\) and novel classes \\( C_N \\), the object score can serve as a general indicator of mask quality. However, when supervision is only provided on \\( C_B \\), the object score is more reflective of the quality of base masks, leading to bias toward \\( C_B \\). But we will show in Sec. 5.4.1 that incorporating object scores still boosts performance on both \\( C_B \\) and \\( C_N \\) by a clear margin. Hence, it is still reasonable and effective to incorporate object scores for all mask proposals." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.687, + 0.469, + 0.824 + ], + "angle": 0, + "content": "Progressive Distillation. To develop an open-world mask proposal network capable of generating masks beyond base classes \\( C_B \\), we propose a progressive distillation strategy. By utilizing the object score as an indicator of mask quality, we can filter high-quality mask proposals that do not overlap with mask annotations of \\( C_B \\), thus producing extra annotations for training. By iteratively repeating this distillation process, the network will be able to segment more concepts progressively and eventually be open-world." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.825, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Specifically, we initialize the teacher model \\(\\mathcal{T}_{\\mu}\\) with the mask proposal network trained on the base annotations \\(\\mathcal{D}_B^{\\prime} = \\{(I_i,\\mathcal{Y}_i^M)\\}_{i = 1}^N\\) without class labels. To produce extra supervision for the student model \\(\\mathcal{T}_{\\theta}\\) on image \\(I_{i}\\), we first obtain inference result \\(\\mathcal{T}_{\\mu}(I_i)\\) from the teacher model." + }, + { + "type": "algorithm", + "bbox": [ + 0.501, + 0.091, + 0.892, + 0.351 + ], + "angle": 0, + "content": "Algorithm 1 Progressive Distillation \nRequire: Initial teacher model \\(\\mathcal{T}_{\\mu}\\) with parameter \\(\\mu\\) \nRequire: Dataset \\(\\mathcal{D}_B' = \\{(I_i, \\mathcal{Y}_i^M)\\}_{i=1}^N\\) (only masks) \nRequire: Score threshold \\(\\alpha\\), IoU threshold \\(\\beta\\) \nfor \\(K\\) iterations do \n\\(\\theta \\gets \\mu\\) ▷ Initialize the student model \\(\\mathcal{T}_{\\theta}\\) \nfor \\((I_i, \\mathcal{Y}_i^M)\\) in \\(\\mathcal{D}_B'\\) do \n\\(\\mathcal{Y} \\gets \\mathcal{Y}_i^M\\) ▷ \\(\\mathcal{Y}\\): supervision for \\(\\mathcal{T}_{\\theta}\\) \n\\(\\hat{\\mathcal{Y}} = \\mathcal{T}_{\\mu}(I_i)\\) \nfor \\(\\hat{y}\\) in \\(\\hat{\\mathcal{Y}}\\) do \nif \\(\\forall y \\in \\mathcal{Y}, IoU(\\hat{y}, y) < \\beta\\) then \nif score(\\(\\hat{y}\\)) > \\(\\alpha\\) then \n\\(\\mathcal{Y} \\gets \\mathcal{Y} \\cup \\{\\hat{y}\\}\\) \n\\(L_{\\theta} = \\mathcal{L}(\\mathcal{T}_{\\theta}(I_i), \\mathcal{Y})\\) \n\\(\\theta \\gets \\theta - \\gamma \\nabla_{\\theta}(L_{\\theta})\\) \n\\(\\mu \\gets \\theta\\) ▷ Update the teacher model \\(\\mathcal{T}_{\\mu}\\)" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.387, + 0.892, + 0.523 + ], + "angle": 0, + "content": "Then we select mask proposals with high object scores that are non-overlap with ground-truth masks in \\(\\mathcal{Y}_i^M\\). These selected masks are considered novel masks and combined with \\(\\mathcal{Y}_i^M\\) to form the supervision \\(\\mathcal{V}\\) for the student model. To further boost generalization, we train the student model progressively by updating the parameters of the student model to the teacher model iteratively. A more detailed algorithm is presented in Alg. 1. Experiments show that our algorithm works surprisingly well." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.554, + 0.652, + 0.569 + ], + "angle": 0, + "content": "4.2.2 MasQ-Tuning" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.585, + 0.892, + 0.761 + ], + "angle": 0, + "content": "Given masks produced by the class-agnostic mask proposal network, we expect to classify each mask region using pretrained CLIP models. To maintain the generalization ability of CLIP models, MaskCLIP [9] freezes all CLIP parameters and appends auxiliary tokens for region classification. According to Eq. (1), for each Mask Class Token \\( x_{\\mathrm{mask}}^{(i)} \\in \\mathbb{R}^C \\), we have its query embedding \\( q_i = f_Q(x_{\\mathrm{mask}}^{(i)}) \\) and attention weight over \\( p \\) CLIP tokens, \\( \\text{softmax}(q_i K_{\\mathrm{img}}^T + \\mathcal{M}_i) \\in \\mathbb{R}^p \\). The attention weight indicates \\( x_{\\mathrm{mask}}^{(i)} \\) where to focus, and \\( V_{\\mathrm{img}} \\) is interpreted as the dense CLIP features that all Mask Class Tokens can extract." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.892, + 0.904 + ], + "angle": 0, + "content": "MaskCLIP preserves the original feature space of CLIP by freezing all parameters, however, it lacks in adaption. Although the appended Mask Class Tokens perform classification similar to the class token in CLIP, there is still a shift between them. Specifically, each Mask Class Token is intended to classify a mask region in an image, while the original class token is designed to extract image-level feature. To enhance adaptation ability, we propose applying new query projections \\( f_{Q}^{\\prime} \\) to each cross-attention layer for" + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.946, + 0.511, + 0.957 + ], + "angle": 0, + "content": "890" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.078, + 0.092, + 0.241, + 0.106 + ], + "angle": 0, + "content": "Mask Class Tokens, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.085, + 0.116, + 0.468, + 0.134 + ], + "angle": 0, + "content": "\\[\n\\operatorname {C r o s s A t t n} (\\cdot) = \\operatorname {s o f t m a x} \\left(\\mathbf {Q} _ {\\text {m a s k}} ^ {\\prime} K _ {\\text {i m g}} ^ {T} + \\mathcal {M} _ {\\text {m a s k}}\\right) \\cdot V _ {\\text {i m g}}, \\tag {4}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.097, + 0.138, + 0.468, + 0.155 + ], + "angle": 0, + "content": "\\[\n\\mathbf {Q} _ {\\text {m a s k}} ^ {\\prime}, K _ {\\text {i m g}}, V _ {\\text {i m g}} = \\mathbf {f} _ {\\mathbf {Q}} ^ {\\prime} \\left(x _ {\\text {m a s k}}\\right), f _ {K} \\left(x _ {\\text {i m g}}\\right), f _ {V} \\left(x _ {\\text {i m g}}\\right). \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.165, + 0.468, + 0.269 + ], + "angle": 0, + "content": "In this way, Mask Class Tokens obtain better attention weights through learning. In addition, since the softmax operator in Eq. (4) serves as a normalizer, the results of Eq. (4) still lie in the sub-space spanned by rows of \\( V_{\\mathrm{img}} \\). \\( V_{\\mathrm{img}} \\) is projected from CLIP tokens and thus preserves the knowledge of CLIP. Therefore, MasQ-Tuning is able to improve adaptation while maintaining generalization." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.271, + 0.468, + 0.316 + ], + "angle": 0, + "content": "To effectively inherit the knowledge and the statistics of CLIP, other layers (layernorm, FFN, and the final projection) are frozen during fine-tuning." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.319, + 0.468, + 0.38 + ], + "angle": 0, + "content": "Losses. Our goal is to match the appended Mask Class Tokens with their corresponding ground-truth labels, so we use the dot-product between Mask Class Tokens and language descriptors as scores and compute cross-entropy loss, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.171, + 0.389, + 0.468, + 0.423 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {c l s}} = - \\log \\left(\\frac {\\exp \\left(s _ {y}\\right)}{\\sum_ {i} \\exp \\left(s _ {i}\\right)}\\right). \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.431, + 0.468, + 0.506 + ], + "angle": 0, + "content": "where \\( s_i \\) denotes the score for \\( i \\)-th class and \\( y \\) is the assigned label for the mask. If a predicted mask is matched to a ground-truth mask according to an IoU threshold, we then assign the mask a label. Otherwise, we use a fixed word, \"background\", as the label for the predicted mask." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.52, + 0.208, + 0.536 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.545, + 0.468, + 0.68 + ], + "angle": 0, + "content": "We evaluate MasQCLIP on three segmentation tasks to demonstrate its effectiveness and universality, and we follow the commonly-used settings in different segmentation tasks. For instance segmentation, we use base-novel setting following [18]. For semantic and panoptic segmentation, we use cross-dataset setting following [9, 13]. We show MasQCLIP achieves state-of-the-art results on all benchmarks with a universal architecture. We also conduct ablation studies to verify our proposed method." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.693, + 0.364, + 0.708 + ], + "angle": 0, + "content": "5.1. Datasets and Evaluation Metrics" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.716, + 0.468, + 0.852 + ], + "angle": 0, + "content": "COCO. In base-novel setting, we use instance segmentation annotations of COCO [25]. Following [18], we partition COCO annotations into 48 base classes for training and 17 novel classes for evaluation. There are 108k training images and 5k validation images. In cross-dataset setting, we use panoptic segmentation [22] annotations of COCO for training, which include 80 thing classes (foreground) and 53 stuff classes (background). There are 118k training images and 5k validation images." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.468, + 0.901 + ], + "angle": 0, + "content": "ADE20k. ADE20k [56, 57] serves for semantic segmentation and panoptic segmentation evaluation under cross-dataset setting. There are 2k validation images in total. The" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.89, + 0.121 + ], + "angle": 0, + "content": "full version (A-847) includes 847 classes and the short version (A-150) includes 150 classes." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.125, + 0.892, + 0.2 + ], + "angle": 0, + "content": "PASCAL-Context. Pascal-Context [29] serves for semantic segmentation evaluation under cross-dataset setting. There are 5k validation images in total. The full version (P-459) includes 459 classes and the short version (P-59) includes 59 classes." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.205, + 0.892, + 0.296 + ], + "angle": 0, + "content": "Evaluation Metrics. For instance segmentation, we report \\(mAP\\) (mean average precision) [25] at IoU (intersection-over-union) of 0.5 following base-novel setting [1, 18, 50]. For semantic segmentation, we report \\(mIoU\\) (mean intersection-over-union) [11] for evaluation. For panoptic segmentation, we report \\(PQ\\) (panoptic quality) [22]." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.308, + 0.716, + 0.324 + ], + "angle": 0, + "content": "5.2. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.332, + 0.892, + 0.467 + ], + "angle": 0, + "content": "Class-Agnostic Mask Proposal Network. We train Mask2Former [7] or Mask R-CNN [14] with ResNet-50 backbone to generate class-agnostic mask proposals. The labels of masks are not used as supervision, and the number of mask proposals for each image is set to 100 for both models. In Mask2Former, the number of classes is set to 1 to obtain the object score. In Mask R-CNN, we adopt the confidence scores of the RPN head as object scores. The default experiment setting for Mask R-CNN is R50-FPN-1x." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.471, + 0.892, + 0.622 + ], + "angle": 0, + "content": "Progressive Distillation. For Mask2Former, we first train the initial teacher model until convergence. Then, we retrain the student model for 2 rounds with 30k iterations each round (under both settings). Unless stated, other experiment settings are set to default as training Mask2Former [7]. For Mask R-CNN, we use the checkpoint of R50-FPN-1x as the initial teacher model. We then re-train the student model for 2 rounds with 10k iterations each round (under both settings). For all models and settings, we set the threshold of object scores \\(\\alpha\\) to 0.8, and the NMS threshold \\(\\beta\\) to 0.1." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.625, + 0.892, + 0.868 + ], + "angle": 0, + "content": "MasQ-Tuning. During fine-tuning, we use the same CLIP model ViT-L/14@336px as in [9]. The language descriptors are simply the text embeddings of category names given by the language encoder of CLIP without any prompt. The number of Mask Class Tokens is set to 100 which is equivalent to the number of mask proposals. The query projection \\( f_{Q}^{\\prime} \\) at each layer exhibits the same architecture of a linear projection as the original \\( f_{Q} \\) in CLIP visual encoder. In both cross-dataset and base-novel settings, we use AdamW [26] as our default optimizer and the initial learning rate is set to 0.0001. We assign a predicted mask a label if it has an IoU higher than 0.6 with a ground-truth mask. We fine-tune for 10k iterations with a batch size of 4, and the learning rate is decreased by a factor of 10 at 9k iterations. During inference, the post-processing follows Mask2Former after obtaining labels for mask proposals." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Settings. For each model architecture (Mask R-CNN or Mask2Former), we train two MasQCLIP models for base-" + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.946, + 0.509, + 0.957 + ], + "angle": 0, + "content": "891" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.084, + 0.088, + 0.885, + 0.228 + ], + "angle": 0, + "content": "
MethodsBackboneInstanceSemanticPanoptic
BaseNovelAllA-150A-847P-59P-459PQ\\( PQ^{th} \\)\\( PQ^{st} \\)
XPM [18]ResNet-5041.521.636.3-------
LSeg+ [23]EffNet-B7---18.03.846.57.8---
OpenSeg [12]EffNet-B7---21.16.342.19.0---
MaskCLIP (Mask R-CNN) [9]ResNet-50---22.46.841.39.112.911.216.1
MaskCLIP (Mask2Former) [9]ResNet-50---23.78.245.910.015.113.518.3
MasQCLIP (Mask R-CNN)ResNet-5040.728.437.523.78.444.414.114.914.515.6
MasQCLIP (Mask2Former)ResNet-5051.031.946.030.410.757.818.223.321.227.7
+9.5+10.3+9.7+6.7+2.5+11.3+8.2+8.2+7.7+9.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.233, + 0.895, + 0.333 + ], + "angle": 0, + "content": "Table 1: Results on open-vocabulary universal image segmentation. We compare MasQCLIP with state-of-the-art models on three segmentation tasks with a universal architecture. We use Mask R-CNN or Mask2Former as our class-agnostic mask proposal network. All methods in the table rely only on COCO dataset for training. a) For instance segmentation, we report mask AP50 following base-novel setting [18]. b) For semantic segmentation, we report mIoU on ADE20k and PASCAL-Context following cross-dataset setting [20]. A-150 and A-847 represent ADE20k with 150 classes and 847 classes respectively. P-59 and P-459 represent PASCAL-Context with 59 classes and 459 classes respectively. c) For panoptic segmentation, we report \\( PQ \\) on ADE20k following cross-dataset setting [9]. We achieve significant improvements on all evaluation metrics." + }, + { + "type": "table", + "bbox": [ + 0.084, + 0.347, + 0.46, + 0.458 + ], + "angle": 0, + "content": "
MethodsConstrainedGeneralized
BaseNovelBaseNovelAll
OVR [50]42.020.941.617.135.2
SB [1]41.620.841.016.034.5
BA-RPN [54]41.820.141.315.434.5
OVR+OMP [2]31.314.130.58.324.7
XPM [18]42.424.041.521.636.3
MasQCLIP (Mask R-CNN)40.930.140.728.437.5
MasQCLIP (Mask2Former)51.234.351.031.946.0
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.462, + 0.47, + 0.56 + ], + "angle": 0, + "content": "Table 2: Results on open-vocabulary instance segmentation. We report mask AP50 in the table. The results presented in the table all use the ResNet-50 backbone. Constrained setting means that the model is evaluated on either base classes or novel classes separately. Generalized setting means that the model is tested jointly on both base and novel classes. Notice that the results of novel classes show the generalization ability of models." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.58, + 0.47, + 0.673 + ], + "angle": 0, + "content": "novel and cross-dataset settings separately. The former model is trained on base classes of COCO-instance dataset and is tested on novel classes (for instance segmentation), while the latter is trained on the COCO-panoptic dataset and is used for both semantic (through post-possessing) and panoptic segmentation evaluation." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.681, + 0.216, + 0.696 + ], + "angle": 0, + "content": "5.3. Main Results" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.704, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Instance Segmentation. We evaluate our MasQCLIP on instance segmentation under base-novel setting. We first train MasQCLIP on base classes of COCO-instance dataset and then evaluate the model on novel classes. The detailed results are presented in Tab. 2. As shown, when using Mask R-CNN as our class-agnostic mask proposal network, we achieve an improvement of 6.8 AP50 on novel classes over XPM [18]. When using Mask2Former, we further achieve an improvement of 10.3 AP50. The evaluation metrics on novel classes mainly reflect the generalization ability of models. Since our relative improvement on novel classes is much higher than that on base classes across two mask proposal networks, our proposed method enjoys better gen" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.351, + 0.813, + 0.366 + ], + "angle": 0, + "content": "eralization ability compared to previous works." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.369, + 0.892, + 0.49 + ], + "angle": 0, + "content": "Semantic Segmentation. We evaluate our MasQCLIP on semantic segmentation under cross-dataset setting. We directly use the model trained on COCO-panoptic dataset for evaluation, and report the results on ADE20ksemantic and PASCAL-Context-semantic datasets in Tab. 1. In terms of \\( mIoU \\), MasQCLIP improves previous state-of-the-art results by 6.7, 2.5, 11.3, and 8.2 on A-150, A-847, P-59, and P-459 datasets respectively." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.494, + 0.893, + 0.645 + ], + "angle": 0, + "content": "Panoptic Segmentation. We evaluate our MasQCLIP on panoptic segmentation under cross-dataset setting. We first train MasQCLIP on COCO-panoptic dataset, and then directly evaluate the model on ADE20k-panoptic dataset. The results are presented in Tab. 1. As shown, when using the same mask proposal network architecture, MasQCLIP outperforms state-of-the-art MaskCLIP [9] by \\(8.2PQ\\). Even adopted with a weaker mask proposal network of Mask R-CNN, MasQCLIP still achieves on-par results on \\(PQ\\) compared with MaskCLIP." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.654, + 0.665, + 0.669 + ], + "angle": 0, + "content": "5.4. Ablation Studies" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.677, + 0.715, + 0.692 + ], + "angle": 0, + "content": "5.4.1 Progressive Distillation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.701, + 0.892, + 0.791 + ], + "angle": 0, + "content": "In this section, we conduct ablation studies on progressive distillation. We evaluate the models on instance segmentation under base-novel setting. The initial teacher model is trained for 100k iterations on base annotations, and the student model is then re-trained for 30k iterations each round using the initial teacher model." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.893, + 0.903 + ], + "angle": 0, + "content": "Object Scores. We first study the importance of object scores. As shown in Tab. 3, incorporating object scores boosts performance on base classes and novel classes significantly. In addition, despite object scores being trained only on base classes, they still serve as reliable indicators of mask quality for novel classes, which demonstrates the generalization of object scores. The results show that it is" + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.946, + 0.511, + 0.957 + ], + "angle": 0, + "content": "892" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.151, + 0.089, + 0.316, + 0.186 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.151, + 0.187, + 0.316, + 0.269 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.214, + 0.273, + 0.252, + 0.287 + ], + "angle": 0, + "content": "Input" + }, + { + "type": "image", + "bbox": [ + 0.318, + 0.089, + 0.481, + 0.186 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.318, + 0.187, + 0.481, + 0.269 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.358, + 0.273, + 0.456, + 0.286 + ], + "angle": 0, + "content": "CLIP Baseline" + }, + { + "type": "image", + "bbox": [ + 0.483, + 0.089, + 0.648, + 0.186 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.483, + 0.187, + 0.648, + 0.269 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.537, + 0.273, + 0.612, + 0.286 + ], + "angle": 0, + "content": "MaskCLIP" + }, + { + "type": "image", + "bbox": [ + 0.652, + 0.089, + 0.817, + 0.186 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.652, + 0.187, + 0.816, + 0.269 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.702, + 0.273, + 0.78, + 0.287 + ], + "angle": 0, + "content": "MasQCLIP" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.293, + 0.892, + 0.322 + ], + "angle": 0, + "content": "Figure 4: Comparison on open-vocabulary instance segmentation. We evaluate on the same set of images as in MaskCLIP [9]. The above two images are from ADE20k dataset. Visualization results show that our mask proposals are more robust and high-quality." + }, + { + "type": "table", + "bbox": [ + 0.121, + 0.336, + 0.427, + 0.381 + ], + "angle": 0, + "content": "
ModelsScoresBaseNovelAll
Mask2Former-16.911.315.4
Mask2Former✓53.822.645.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.385, + 0.47, + 0.44 + ], + "angle": 0, + "content": "Table 3: Ablations on Object Scores. We report mask AP50 in the table. Models denote the architecture of class-agnostic mask proposal networks. Scores denote whether we incorporate object scores." + }, + { + "type": "table", + "bbox": [ + 0.134, + 0.448, + 0.415, + 0.535 + ], + "angle": 0, + "content": "
TeacherStudentBaseNovelAll
100k-53.822.645.6
100k30k×150.626.144.2
100k30k×251.031.946.0
100k30k×351.231.246.0
200k-54.718.245.1
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.539, + 0.47, + 0.609 + ], + "angle": 0, + "content": "Table 4: Ablations on Iterative Re-training. We report mask AP50 in the table. We adopt the Mask2Former architecture and incorporate object scores by default. Teacher denotes the training iterations of the initial teacher model, and Student denotes how we train the student model progressively." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.625, + 0.469, + 0.656 + ], + "angle": 0, + "content": "reasonable to consider object scores as a general indicator of mask quality." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.659, + 0.47, + 0.779 + ], + "angle": 0, + "content": "Iterative Re-training. Tab. 4 shows the effectiveness of progressive distillation. After we train the student model for 2 rounds progressively, the model performance improves on novel classes by 9.3 AP50. Although the results manifest a slight performance drop on base classes, it can be explained that the model is balancing between the base and extra (novel) annotations, thus leading the model to be less overfitted on base classes." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.471, + 0.902 + ], + "angle": 0, + "content": "If we continue to train the student model for more rounds (e.g. 3 rounds), the model does not gain further improvement in generalization ability, indicating that there might exist an upper bound for the progressive distillation process. In addition, we also show that the improvement on novel classes cannot simply gain from a longer training schedule. When training the network for another 100k iterations without progressive distillation, there is a notable performance" + }, + { + "type": "table", + "bbox": [ + 0.504, + 0.336, + 0.894, + 0.439 + ], + "angle": 0, + "content": "
MethodsQKVAllParamADE20kCOCO
PQmIoUPQmIoU
Freeze-----10.715.719.422.1
Tune-V--✓-25M14.418.050.063.2
Tune-QKV✓✓✓-75M14.918.650.563.5
Tune-CLIP✓✓✓✓304M14.718.349.063.6
Tune-K-✓--25M22.529.848.361.6
Tune-QK✓✓--50M22.930.149.062.3
Tune-Q (ours)✓---25M23.330.448.562.0
" + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.444, + 0.894, + 0.556 + ], + "angle": 0, + "content": "Table 5: Ablations on MasQ-Tuning. We try different fine-tuning strategies. \\( Q, K, V \\) means the newly added query, key, and value projections for Mask Class Tokens respectively, and All means all the newly added parameters (also including layernorm, FFN, and the final projection). Param denotes the total number of trainable parameters. The models are first trained on COCO and then evaluated on ADE20k. We note that the metrics on ADE20k mainly show the generalization ability." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.572, + 0.892, + 0.618 + ], + "angle": 0, + "content": "drop of 4.4 AP50 (from 22.6 to 18.2) on novel classes. Our observation supports that improvement of model performance indeed comes from progressive distillation." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.632, + 0.653, + 0.647 + ], + "angle": 0, + "content": "5.4.2 MasQ-Tuning" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.656, + 0.892, + 0.687 + ], + "angle": 0, + "content": "To validate our fine-tuning method, MasQ-Tuning, we build several baselines to prove its effectiveness." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.701, + 0.891, + 0.731 + ], + "angle": 0, + "content": "- Freeze: Same as the MaskCLIP w/o RMA baseline in [9]. We incorporate object scores during inference." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.735, + 0.892, + 0.78 + ], + "angle": 0, + "content": "- Tune-Q: Only query projections \\( f_{Q}^{\\prime} \\) for Mask Class Tokens are learnable during fine-tuning. Notice that MasQCLIP adopts this fine-tuning strategy." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.784, + 0.891, + 0.814 + ], + "angle": 0, + "content": "- Tune-K: Only key projections \\( f_{K}^{\\prime} \\) for Mask Class Tokens are learnable during fine-tuning." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.818, + 0.891, + 0.848 + ], + "angle": 0, + "content": "- Tune-V: Only value projections \\( f_V' \\) for Mask Class Tokens are learnable during fine-tuning." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.852, + 0.891, + 0.883 + ], + "angle": 0, + "content": "- Tune-QK: Query and key projections for Mask Class Tokens (\\( f_{Q}^{\\prime} \\) and \\( f_{K}^{\\prime} \\)), are learnable during fine-tuning." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.886, + 0.891, + 0.901 + ], + "angle": 0, + "content": "- Tune-QKV: Query, key, and value projections for Mask" + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.701, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.946, + 0.511, + 0.957 + ], + "angle": 0, + "content": "893" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.15, + 0.088, + 0.283, + 0.168 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.194, + 0.171, + 0.239, + 0.184 + ], + "angle": 0, + "content": "Image" + }, + { + "type": "image", + "bbox": [ + 0.284, + 0.089, + 0.417, + 0.167 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.339, + 0.17, + 0.364, + 0.182 + ], + "angle": 0, + "content": "GT" + }, + { + "type": "image", + "bbox": [ + 0.225, + 0.185, + 0.254, + 0.206 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.225, + 0.209, + 0.256, + 0.219 + ], + "angle": 0, + "content": "house" + }, + { + "type": "image", + "bbox": [ + 0.264, + 0.186, + 0.292, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.264, + 0.209, + 0.291, + 0.219 + ], + "angle": 0, + "content": "sky" + }, + { + "type": "image", + "bbox": [ + 0.339, + 0.186, + 0.366, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.339, + 0.209, + 0.365, + 0.219 + ], + "angle": 0, + "content": "grass" + }, + { + "type": "image", + "bbox": [ + 0.375, + 0.186, + 0.412, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.377, + 0.209, + 0.402, + 0.219 + ], + "angle": 0, + "content": "land" + }, + { + "type": "image", + "bbox": [ + 0.419, + 0.09, + 0.551, + 0.167 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.454, + 0.17, + 0.516, + 0.184 + ], + "angle": 0, + "content": "OpenSeg" + }, + { + "type": "image", + "bbox": [ + 0.415, + 0.186, + 0.449, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.415, + 0.209, + 0.449, + 0.219 + ], + "angle": 0, + "content": "tree" + }, + { + "type": "image", + "bbox": [ + 0.451, + 0.186, + 0.48, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.452, + 0.209, + 0.477, + 0.219 + ], + "angle": 0, + "content": "brick" + }, + { + "type": "image", + "bbox": [ + 0.498, + 0.186, + 0.534, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.209, + 0.516, + 0.219 + ], + "angle": 0, + "content": "ock" + }, + { + "type": "image", + "bbox": [ + 0.526, + 0.186, + 0.552, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.527, + 0.209, + 0.551, + 0.219 + ], + "angle": 0, + "content": "river" + }, + { + "type": "image", + "bbox": [ + 0.554, + 0.09, + 0.686, + 0.167 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.583, + 0.17, + 0.657, + 0.183 + ], + "angle": 0, + "content": "MaskCLIP" + }, + { + "type": "image", + "bbox": [ + 0.554, + 0.186, + 0.59, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.554, + 0.209, + 0.587, + 0.219 + ], + "angle": 0, + "content": "wall" + }, + { + "type": "image", + "bbox": [ + 0.595, + 0.186, + 0.638, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.595, + 0.209, + 0.638, + 0.219 + ], + "angle": 0, + "content": "building" + }, + { + "type": "image", + "bbox": [ + 0.662, + 0.09, + 0.686, + 0.167 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.662, + 0.186, + 0.697, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.662, + 0.209, + 0.692, + 0.219 + ], + "angle": 0, + "content": "roo" + }, + { + "type": "image", + "bbox": [ + 0.69, + 0.09, + 0.822, + 0.167 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.716, + 0.17, + 0.794, + 0.184 + ], + "angle": 0, + "content": "MasQCLIP" + }, + { + "type": "image", + "bbox": [ + 0.69, + 0.186, + 0.738, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.706, + 0.209, + 0.745, + 0.219 + ], + "angle": 0, + "content": "window" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.225, + 0.894, + 0.255 + ], + "angle": 0, + "content": "Figure 5: Comparison on open-vocabulary semantic segmentation. We evaluate on the same image as in OpenSeg [12]. Notice that MasQCLIP successfully recognizes the windows on the house, demonstrating that MasQCLIP is able to classify small objects." + }, + { + "type": "image", + "bbox": [ + 0.197, + 0.268, + 0.425, + 0.373 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.197, + 0.374, + 0.423, + 0.478 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.197, + 0.479, + 0.423, + 0.583 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.426, + 0.269, + 0.594, + 0.373 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.427, + 0.374, + 0.594, + 0.478 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.427, + 0.479, + 0.594, + 0.583 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.598, + 0.269, + 0.777, + 0.373 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.598, + 0.374, + 0.777, + 0.478 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.598, + 0.479, + 0.776, + 0.583 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.593, + 0.893, + 0.636 + ], + "angle": 0, + "content": "Figure 6: Comparison on open-vocabulary panoptic segmentation. We evaluate on the same set of images as in MaskCLIP [9]. The images are from ADE20k dataset. Visualization shows that MasQCLIP produces higher-quality masks and has higher classification accuracy." + }, + { + "type": "text", + "bbox": [ + 0.108, + 0.653, + 0.469, + 0.684 + ], + "angle": 0, + "content": "Class Tokens \\((f_{Q}^{\\prime}, f_{K}^{\\prime}\\), and \\(f_{V}^{\\prime}\\)), are learnable during fine-tuning." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.687, + 0.47, + 0.749 + ], + "angle": 0, + "content": "- Tune-CLIP: A new set of CLIP parameters is learned during fine-tuning, and masked-cross attention is performed between Mask Class Tokens and CLIP tokens. We use CLIP parameters as initialization." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.761, + 0.47, + 0.852 + ], + "angle": 0, + "content": "In this ablation study, we test the models on semantic and panoptic segmentation under cross-dataset setting. We use the same class-agnostic mask proposal network for all models, and then fine-tune the mask classification module based on the predicted masks. Training settings are all kept the same. Our results are shown in Tab. 5." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Adaptation. We compare the evaluation metrics of the above methods on COCO dataset to show the strong adaptation ability of MasQ-Tuning. Compared to Freeze with 19.4" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.653, + 0.895, + 0.82 + ], + "angle": 0, + "content": "\\(PQ\\) and 22.1 mIoU on COCO, Tune-Q has a significant improvement of 29.1 \\(PQ\\) (from 19.4 to 48.5) and 39.9 mIoU (from 22.1 to 62.0) respectively. This shows that the improvement on adaptation ability should be credited to those learnable query projections \\(f_{Q}^{\\prime}\\) for Mask Class Tokens. In addition, compared to Tune-CLIP with 49.0 \\(PQ\\) and 63.6 mIoU on COCO, Tune-Q has much fewer learnable parameters, but only has little performance drop (-0.5 \\(PQ\\) and -1.6 mIoU). This indicates that simply adding more parameters is not helpful, and our proposed MasQ-Tuning has achieved impressive adaptation ability." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Generalization. We now focus on the performance of the above methods on ADE20k dataset to show the strong generalization ability of MasQ-Tuning. When adding learnable value projections \\( f_V' \\) for Mask Class Tokens, the model cannot generalize well to ADE20k dataset. Compared to" + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.945, + 0.512, + 0.957 + ], + "angle": 0, + "content": "894" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.193, + 0.089, + 0.411, + 0.186 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.192, + 0.187, + 0.412, + 0.284 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.217, + 0.288, + 0.387, + 0.301 + ], + "angle": 0, + "content": "(a) \"a black cat\", \"an orange cat\"" + }, + { + "type": "image", + "bbox": [ + 0.418, + 0.089, + 0.583, + 0.187 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.418, + 0.187, + 0.583, + 0.284 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.457, + 0.288, + 0.554, + 0.301 + ], + "angle": 0, + "content": "(b) \"beer\", \"wine\"" + }, + { + "type": "image", + "bbox": [ + 0.589, + 0.089, + 0.776, + 0.187 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.589, + 0.187, + 0.776, + 0.284 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.625, + 0.288, + 0.749, + 0.301 + ], + "angle": 0, + "content": "(c) \"an adult\", \"a child\"" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.307, + 0.894, + 0.336 + ], + "angle": 0, + "content": "Figure 7: User-specified segmentation. We use the model trained on COCO-panoptic for evaluation. Visualization results show that our model can distinguish subtle differences among objects." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.36, + 0.47, + 0.512 + ], + "angle": 0, + "content": "Tune-Q with 23.3 PQ, Tune-V, Tune-QKV and Tune-CLIP have a performance drop of 8.9, 8.4, and 8.6 on \\( PQ \\) respectively. This proves the importance of freezing \\( V_{\\mathrm{img}} \\) which is interpreted as dense CLIP features. By inheriting \\( V_{\\mathrm{img}} \\) from the CLIP model, MasQCLIP is able to preserve the original feature space within CLIP. Compared to Tune-QK, Tune-Q reaches better performance on ADE20k and is more parameter-efficient, where only \\( 8.2\\% \\) of original parameters in CLIP visual encoder are added for training. Therefore, we choose Tune-Q as the fine-tuning strategy of MasQCLIP." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.529, + 0.26, + 0.545 + ], + "angle": 0, + "content": "5.5. Qualitative Results" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.555, + 0.47, + 0.751 + ], + "angle": 0, + "content": "In this section, we compare the visualization results of MasQCLIP with previous models [9, 12]. The results of instance, semantic, and panoptic segmentation are presented in Fig. 4, Fig. 5, and Fig. 6 respectively. For a fair comparison, We all use the same set of images as previous works [9, 12]. We observe from the visualization results that MasQCLIP produces more robust mask proposals and enjoys a higher mask classification accuracy, which corresponds to our two key components proposed in MasQCLIP. As shown in Fig. 7, MasQCLIP exhibits the ability to segment objects of arbitrary classes as per user specifications and to discriminate between subtle distinctions within them (e.g. \"beer\" vs. \"wine\", \"child\" vs. \"adult\")." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.769, + 0.191, + 0.786 + ], + "angle": 0, + "content": "5.6. Efficiency" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.469, + 0.9 + ], + "angle": 0, + "content": "MasQCLIP exhibits great capability in open-vocabulary universal segmentation while being computationally efficient at the same time. We report the results of GFLOPs in Tab. 6. As shown, the GFLOPs of MasQCLIP is only \\(14.5\\%\\) higher than the combined GFLOPs of Mask2Former and CLIP visual encoder, and is \\(34.1\\%\\) lower than the GFLOPs of MaskCLIP." + }, + { + "type": "table", + "bbox": [ + 0.57, + 0.357, + 0.821, + 0.43 + ], + "angle": 0, + "content": "
ModelsGFLOPs
Mask2Former [7]78.9
CLIP Visual Encoder [31]233.0
MaskCLIP† [9]542.0
MasQCLIP (ours)357.2
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.435, + 0.894, + 0.492 + ], + "angle": 0, + "content": "Table 6: Model efficiency. The resolution of input images is set to \\(640 \\times 640\\) for Mask2Former and \\(336 \\times 336\\) for CLIP Visual Encoder. We use the CLIP model ViT-L/14@336px. \\(\\dagger\\) means our re-implement according to the paper (no public codes available)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.51, + 0.627, + 0.526 + ], + "angle": 0, + "content": "6. Conclusions" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.536, + 0.892, + 0.688 + ], + "angle": 0, + "content": "We propose a two-stage model, MasQCLIP, for open-vocabulary universal segmentation. We first design a progressive distillation process for the class-agnostic mask proposal network to segment open-world masks. Additionally, we adapt CLIP models for mask (region) classification while maintaining the generalization ability of CLIP through our proposed MasQ-Tuning method. We achieve state-of-the-art results with substantial improvement over the existing approaches across three open-vocabulary tasks including instance, semantic, and panoptic segmentation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.691, + 0.892, + 0.798 + ], + "angle": 0, + "content": "Limitations. Since MasQCLIP is built on top of a pretrained CLIP model, though fine-tuning is introduced, the performance of our model is nevertheless largely decided by the generalization ability of the CLIP model. Another limitation of our method is that mask proposals are generated by a fixed network (once pre-trained), which might limit its capability for object types of arbitrary specification." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.801, + 0.892, + 0.83 + ], + "angle": 0, + "content": "Acknowledgement. This work is supported by NSF Award IIS-2127544." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.847, + 0.597, + 0.862 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.508, + 0.873, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[1] Ankan Bansal, Karan Sikka, Gaurav Sharma, Rama Chellappa, and Ajay Divakaran. Zero-shot object detection. In" + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.946, + 0.511, + 0.957 + ], + "angle": 0, + "content": "895" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.111, + 0.093, + 0.468, + 0.12 + ], + "angle": 0, + "content": "Proceedings of the European Conference on Computer Vision, pages 384-400, 2018. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.122, + 0.47, + 0.191 + ], + "angle": 0, + "content": "[2] David Biertimpel, Sindi Shkodrani, Anil S Baslamisli, and Nóra Baka. Prior to segment: Foreground cues for weakly annotated classes in partially supervised instance segmentation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2824-2833, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.192, + 0.471, + 0.234 + ], + "angle": 0, + "content": "[3] Maxime Bucher, Tuan-Hung Vu, Matthieu Cord, and Patrick Pérez. Zero-shot semantic segmentation. Advances in Neural Information Processing Systems, 32, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.236, + 0.471, + 0.29 + ], + "angle": 0, + "content": "[4] Han Cai, Chuang Gan, Ligeng Zhu, and Song Han. Tinytl: Reduce memory, not parameters for efficient on-device learning. Advances in Neural Information Processing Systems, 33:11285-11297, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.293, + 0.471, + 0.348 + ], + "angle": 0, + "content": "[5] Zhaowei Cai, Gukyeong Kwon, Avinash Ravichandran, Erhan Bas, Zhuowen Tu, Rahul Bhotika, and Stefano Soatto. X-detr: A versatile architecture for instance-wise vision-language tasks. arXiv preprint arXiv:2204.05626, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.35, + 0.47, + 0.418 + ], + "angle": 0, + "content": "[6] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Proceedings of the European Conference on Computer Vision, pages 213-229. Springer, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.42, + 0.471, + 0.489 + ], + "angle": 0, + "content": "[7] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1290–1299, 2022. 1, 2, 5, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.491, + 0.47, + 0.545 + ], + "angle": 0, + "content": "[8] Bowen Cheng, Alex Schwing, and Alexander Kirillov. Per-pixel classification is not all you need for semantic segmentation. Advances in Neural Information Processing Systems, 34:17864-17875, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.548, + 0.47, + 0.602 + ], + "angle": 0, + "content": "[9] Zheng Ding, Jieke Wang, and Zhuowen Tu. Open-vocabulary universal image segmentation with maskclip. In International Conference on Machine Learning, 2023. 1, 2, 3, 4, 5, 6, 7, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.604, + 0.47, + 0.687 + ], + "angle": 0, + "content": "[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.689, + 0.47, + 0.757 + ], + "angle": 0, + "content": "[11] Mark Everingham, SM Eslami, Luc Van Gool, Christopher KI Williams, John Winn, and Andrew Zisserman. The Pascal visual object classes challenge: A retrospective. International Journal of Computer Vision, 111(1):98-136, 2015. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.759, + 0.47, + 0.815 + ], + "angle": 0, + "content": "[12] Golnaz Ghiasi, Xiuye Gu, Yin Cui, and Tsung-Yi Lin. Scaling open-vocabulary image segmentation with image-level labels. In Proceedings of the European Conference on Computer Vision, pages 540-557. Springer, 2022. 2, 6, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.817, + 0.47, + 0.871 + ], + "angle": 0, + "content": "[13] Xiuye Gu, Tsung-Yi Lin, Weicheng Kuo, and Yin Cui. Open-vocabulary object detection via vision and language knowledge distillation. In International Conference on Learning Representations, 2022. 1, 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[14] Kaiming He, Georgia Gkioxari, Piotr Dólar, and Ross Girshick. Mask r-cnn. In Proceedings of the IEEE International" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.093, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.119 + ], + "angle": 0, + "content": "Conference on Computer Vision, pages 2961-2969, 2017. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.121, + 0.892, + 0.176 + ], + "angle": 0, + "content": "[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.178, + 0.892, + 0.23 + ], + "angle": 0, + "content": "[16] Xuehai He, Chunyuan Li, Pengchuan Zhang, Jianwei Yang, and Xin Eric Wang. Parameter-efficient fine-tuning for vision transformers. arXiv preprint arXiv:2203.16329, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.233, + 0.892, + 0.273 + ], + "angle": 0, + "content": "[17] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, et al. Distilling the knowledge in a neural network. arXiv preprint arXiv:1503.02531, 2015. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.275, + 0.892, + 0.343 + ], + "angle": 0, + "content": "[18] Dat Huynh, Jason Kuen, Zhe Lin, Jiumiang Gu, and Ehsan Elhamifar. Open-vocabulary instance segmentation via robust cross-modal pseudo-labeling. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7020-7031, 2022. 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.345, + 0.892, + 0.412 + ], + "angle": 0, + "content": "[19] Jaedong Hwang, Seoung Wug Oh, Joon-Young Lee, and Bohyung Han. Exemplar-based open-set panoptic segmentation network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1175–1184, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.414, + 0.892, + 0.495 + ], + "angle": 0, + "content": "[20] Chao Jia, Yinfei Yang, Ye Xia, Yi-Ting Chen, Zarana Parekh, Hieu Pham, Quoc Le, Yun-Hsuan Sung, Zhen Li, and Tom Duerig. Scaling up visual and vision-language representation learning with noisy text supervision. In International Conference on Machine Learning, pages 4904-4916, 2021. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.497, + 0.892, + 0.564 + ], + "angle": 0, + "content": "[21] Menglin Jia, Luming Tang, Bor-Chun Chen, Claire Cardie, Serge Belongie, Bharath Hariharan, and Ser-Nam Lim. Visual prompt tuning. In Proceedings of the European Conference on Computer Vision, pages 709-727. Springer, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.567, + 0.892, + 0.621 + ], + "angle": 0, + "content": "[22] Alexander Kirillov, Kaiming He, Ross Girshick, Carsten Rother, and Piotr Dollar. Panoptic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9404-9413, 2019. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.623, + 0.892, + 0.676 + ], + "angle": 0, + "content": "[23] Boyi Li, Kilian Q Weinberger, Serge Belongie, Vladlen Koltun, and René Ranftl. Language-driven semantic segmentation. In International Conference on Learning Representations, 2022. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.679, + 0.892, + 0.761 + ], + "angle": 0, + "content": "[24] Liunian Harold Li, Pengchuan Zhang, Haotian Zhang, Jianwei Yang, Chunyuan Li, Yiwu Zhong, Lijuan Wang, Lu Yuan, Lei Zhang, Jenq-Neng Hwang, et al. Grounded language-image pre-training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10965-10975, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.763, + 0.892, + 0.831 + ], + "angle": 0, + "content": "[25] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In Proceedings of the European Conference on Computer Vision, pages 740-755. Springer, 2014. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.832, + 0.892, + 0.871 + ], + "angle": 0, + "content": "[26] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In International Conference on Learning Representations, 2018. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.873, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[27] Huaishao Luo, Lei Ji, Ming Zhong, Yang Chen, Wen Lei, Nan Duan, and Tianrui Li. Clip4clip: An empirical study" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.487, + 0.946, + 0.512, + 0.956 + ], + "angle": 0, + "content": "896" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.47, + 0.12 + ], + "angle": 0, + "content": "of clip for end to end video clip retrieval. arXiv preprint arXiv:2104.08860, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.471, + 0.203 + ], + "angle": 0, + "content": "[28] Luke Melas-Kyriazi, Christian Rupprecht, Iro Laina, and Andrea Vedaldi. Deep spectral methods: A surprisingly strong baseline for unsupervised semantic segmentation and localization. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8364-8375, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.205, + 0.471, + 0.288 + ], + "angle": 0, + "content": "[29] Roozbeh Mottaghi, Xianjie Chen, Xiaobai Liu, Nam-Gyu Cho, Seong-Whan Lee, Sanja Fidler, Raquel Urtasun, and Alan Yuille. The role of context for object detection and semantic segmentation in the wild. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 891–898, 2014. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.289, + 0.471, + 0.357 + ], + "angle": 0, + "content": "[30] Or Patashnik, Zongze Wu, Eli Shechtman, Daniel Cohen-Or, and Dani Lischinski. Styleclip: Text-driven manipulation of stylegan imagery. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2085–2094, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.358, + 0.471, + 0.44 + ], + "angle": 0, + "content": "[31] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning, pages 8748-8763. PMLR, 2021. 1, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.442, + 0.471, + 0.524 + ], + "angle": 0, + "content": "[32] Yongming Rao, Wenliang Zhao, Guangyi Chen, Yansong Tang, Zheng Zhu, Guan Huang, Jie Zhou, and Jiwen Lu. Denseclip: Language-guided dense prediction with context-aware prompting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18082-18091, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.525, + 0.471, + 0.579 + ], + "angle": 0, + "content": "[33] Sylvestre-Alvise Rebuffi, Hakan Bilen, and Andrea Vedaldi. Learning multiple visual domains with residual adapters. Advances in Neural Information Processing Systems, 30, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.581, + 0.471, + 0.649 + ], + "angle": 0, + "content": "[34] Mark Sandler, Andrey Zhmoginov, Max Vlademyrov, and Andrew Jackson. Fine-tuning image transformers using learnable memory. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12155-12164, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.65, + 0.471, + 0.718 + ], + "angle": 0, + "content": "[35] Sheng Shen, Liunian Harold Li, Hao Tan, Mohit Bansal, Anna Rohrbach, Kai-Wei Chang, Zhewei Yao, and Kurt Keutzer. How much can clip benefit vision-and-language tasks? In International Conference on Learning Representations, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.72, + 0.471, + 0.789 + ], + "angle": 0, + "content": "[36] Jamie Shotton, John Winn, Carsten Rother, and Antonio Criminisi. Textonboost: Joint appearance, shape and context modeling for multi-class object recognition and segmentation. In Proceedings of the European Conference on Computer Vision, pages 1-15. Springer, 2006. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.79, + 0.471, + 0.831 + ], + "angle": 0, + "content": "[37] Karen Simonyan and Andrew Zisserman. Very deep convolutional networks for large-scale image recognition. arXiv preprint arXiv:1409.1556, 2014. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.832, + 0.471, + 0.9 + ], + "angle": 0, + "content": "[38] Yi-Lin Sung, Jaemin Cho, and Mohit Bansal. VI-adapter: Parameter-efficient transfer learning for vision-and-language tasks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5227-5237, 2022. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "[39] Zhuowen Tu. Auto-context and its application to high-level vision tasks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1-8. IEEE, 2008. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.15, + 0.892, + 0.205 + ], + "angle": 0, + "content": "[40] Zhuowen Tu, Xiangrong Chen, Alan L Yuille, and Song-Chun Zhu. Image parsing: Unifying segmentation, detection, and recognition. International Journal of Computer Vision, 63(2):113-140, 2005. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.207, + 0.892, + 0.262 + ], + "angle": 0, + "content": "[41] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in Neural Information Processing Systems, 30, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.264, + 0.892, + 0.333 + ], + "angle": 0, + "content": "[42] Weiyao Wang, Matt Feiszli, Heng Wang, Jitendra Malik, and Du Tran. Open-world instance segmentation: Exploiting pseudo ground truth from learned pairwise affinity. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4422-4432, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.335, + 0.892, + 0.417 + ], + "angle": 0, + "content": "[43] Xinlong Wang, Zhiding Yu, Shalini De Mello, Jan Kautz, Anima Anandkumar, Chunhua Shen, and Jose M Alvarez. Freesolo: Learning to segment objects without annotations. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14176-14186, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.42, + 0.892, + 0.488 + ], + "angle": 0, + "content": "[44] Zhecan Wang, Noel Codella, Yen-Chun Chen, Luowei Zhou, Jianwei Yang, Xiyang Dai, Bin Xiao, Haoxuan You, Shih-Fu Chang, and Lu Yuan. Clip-td: Clip targeted distillation for vision-language tasks. arXiv preprint arXiv:2201.05729, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.491, + 0.892, + 0.56 + ], + "angle": 0, + "content": "[45] Yuwen Xiong, Renjie Liao, Hengshuang Zhao, Rui Hu, Min Bai, Ersin Yumer, and Raquel Urtasun. Upsnet: A unified panoptic segmentation network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.562, + 0.892, + 0.631 + ], + "angle": 0, + "content": "[46] Mengde Xu, Zheng Zhang, Fangyun Wei, Yutong Lin, Yue Cao, Han Hu, and Xiang Bai. A simple baseline for open-vocabulary semantic segmentation with pre-trained vision-language model. In Proceedings of the European Conference on Computer Vision, pages 736-753. Springer, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.633, + 0.892, + 0.701 + ], + "angle": 0, + "content": "[47] Lihe Yang, Wei Zhuo, Lei Qi, Yinghuan Shi, and Yang Gao. St++: Make self-training work better for semi-supervised semantic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4268-4277, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.704, + 0.892, + 0.773 + ], + "angle": 0, + "content": "[48] Jianlong Yuan, Yifan Liu, Chunhua Shen, Zhibin Wang, and Hao Li. A simple baseline for semi-supervised semantic segmentation with strong data augmentation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 8229-8238, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.775, + 0.892, + 0.83 + ], + "angle": 0, + "content": "[49] Yuhang Zang, Wei Li, Kaiyang Zhou, Chen Huang, and Chen Change Loy. Open-vocabulary detr with conditional matching. In Proceedings of the European Conference on Computer Vision, pages 106-122, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.832, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[50] Alireza Zareian, Kevin Dela Rosa, Derek Hao Hu, and Shih-Fu Chang. Open-vocabulary object detection using captions. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14393-14402, 2021. 2, 5, 6" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.487, + 0.946, + 0.511, + 0.956 + ], + "angle": 0, + "content": "897" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.161 + ], + "angle": 0, + "content": "[51] Jeffrey O Zhang, Alexander Sax, Amir Zamir, Leonidas Guibas, and Jitendra Malik. Side-tuning: a baseline for network adaptation via additive side networks. In Proceedings of the European Conference on Computer Vision, pages 698-714. Springer, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.163, + 0.472, + 0.233 + ], + "angle": 0, + "content": "[52] Linfeng Zhang, Jiebo Song, Anni Gao, Jingwei Chen, Chenglong Bao, and Kaisheng Ma. Be your own teacher: Improve the performance of convolutional neural networks via self distillation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 3713-3722, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.234, + 0.472, + 0.302 + ], + "angle": 0, + "content": "[53] Renrui Zhang, Rongyao Fang, Wei Zhang, Peng Gao, Kunchang Li, Jifeng Dai, Yu Qiao, and Hongsheng Li. Tip-adapter: Training-free clip-adapter for better vision-language modeling. arXiv preprint arXiv:2111.03930, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.304, + 0.472, + 0.359 + ], + "angle": 0, + "content": "[54] Ye Zheng, Jiahong Wu, Yongqiang Qin, Faen Zhang, and Li Cui. Zero-shot instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2593-2602, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.361, + 0.472, + 0.444 + ], + "angle": 0, + "content": "[55] Yiwu Zhong, Jianwei Yang, Pengchuan Zhang, Chunyuan Li, Noel Codella, Liunian Harold Li, Luowei Zhou, Xiyang Dai, Lu Yuan, Yin Li, and Jianfeng Gao. Regionclip: Region-based language-image pretraining. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 16793-16803, 2022. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.445, + 0.472, + 0.514 + ], + "angle": 0, + "content": "[56] Bolei Zhou, Hang Zhao, Xavier Puig, Sanja Fidler, Adela Barriuso, and Antonio Torralba. Scene parsing through ade20k dataset. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 633-641, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.515, + 0.472, + 0.571 + ], + "angle": 0, + "content": "[57] Bolei Zhou, Hang Zhao, Xavier Puig, Tete Xiao, Sanja Fidler, Adela Barriuso, and Antonio Torralba. Semantic understanding of scenes through the ade20k dataset. International Journal of Computer Vision, 127(3):302-321, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.572, + 0.472, + 0.626 + ], + "angle": 0, + "content": "[58] Chong Zhou, Chen Change Loy, and Bo Dai. Extract free dense labels from clip. In Proceedings of the European Conference on Computer Vision, pages 696-712. Springer, 2022. 2" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.472, + 0.626 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.487, + 0.946, + 0.511, + 0.956 + ], + "angle": 0, + "content": "898" + } + ] +] \ No newline at end of file diff --git a/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/0636ab48-f4a3-4a28-9365-8ed3c11dca4b_origin.pdf b/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/0636ab48-f4a3-4a28-9365-8ed3c11dca4b_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..cdc608c0167b7601784580df1f2bbe34f7f97c04 --- /dev/null +++ b/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/0636ab48-f4a3-4a28-9365-8ed3c11dca4b_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:0ccb1978f7981bfb46223747b8d4691e6af5e34afb9a644453b8c3b1b710ed4b +size 3009536 diff --git a/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/full.md b/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/full.md new file mode 100644 index 0000000000000000000000000000000000000000..7e4ae605f8fe49958f33e27200e69693a1c5d6fb --- /dev/null +++ b/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/full.md @@ -0,0 +1,457 @@ +# MasQCLIP for Open-Vocabulary Universal Image Segmentation + +Xin $\mathrm{Xu}^{1*}$ , Tianyi $\mathrm{Xiong}^{2*}$ , Zheng $\mathrm{Ding}^3$ , and Zhuowen $\mathrm{Tu}^3$ + +1Peking University + +$^{2}$ Tsinghua University + +3University of California, San Diego + +# Abstract + +We present a new method for open-vocabulary universal image segmentation, which is capable of performing instance, semantic, and panoptic segmentation under a unified framework. Our approach, called MasQCLIP, seamlessly integrates with a pre-trained CLIP model by utilizing its dense features, thereby circumventing the need for extensive parameter training. MasQCLIP emphasizes two new aspects when building an image segmentation method with a CLIP model: 1) a student-teacher module to deal with masks of the novel (unseen) classes by distilling information from the base (seen) classes; 2) a fine-tuning process to update model parameters for the queries $Q$ within the CLIP model. Thanks to these two simple and intuitive designs, MasQCLIP is able to achieve state-of-the-art performances with a substantial gain over the competing methods by a large margin across all three tasks, including open-vocabulary instance, semantic, and panoptic segmentation. Project page is at https://masqclip.github.io/. + +# 1. Introduction + +By being universal and open-world, the traditional image segmentation methods that have been mainly trained in a supervised manner can be made less specific and more powerful. When an image segmentation method is open-world, it means that it can handle new concepts with novel classes or categories that are not labeled in its supervised training data. However, this is not something that can be achieved by the algorithm alone, as information about the novel classes that go beyond supervised labels cannot be generated out of thin air. Fortunately, the CLIP models [31] are trained on millions of image-text pairs, which provides a rich source of combinatorial object/scene information by mapping images and texts into the same semantic space. + +![](images/8a117942400126da50eea6613d51923129d0ebb32b65ada22476d0eba2c993e1.jpg) + +![](images/315e1c785e7a16abeba1a14d1455f93f6562aecdd3b37845a2c5a4ae5eccd95f.jpg) +Mask AP50 on COCO Split + +![](images/2220f69fbd09bb6c62a784be26762ce5ddcd2137d3095f430200475ca9950a69.jpg) + +![](images/9346a82e2d2e27c90aadd778c0fbdd0bf7fa6c65cf6440732b1eaef6b34e05ce.jpg) +mIoU on ADE20k + +![](images/36527c69802f632a96a027de3a1a417299e760ac78347d0a9d6078363c29eef4.jpg) + +![](images/3dd716ce9f3e6670a7c0682d0bec0fe23724404cd3c9a2fe1ad6a78b7bab5ddc.jpg) +PQ on ADE20k + +![](images/95273bac1d60a4d9164d3f13a2bc6a5fb7c2a72a2211bac682038faabda24a05.jpg) +Figure 1: We present the visualization and quantitative results of MasQCLIP on open-vocabulary segmentation with a universal model architecture. As shown, we achieve state-of-the-art performances across three segmentation tasks. + +![](images/e51e0a63327320e81b59e65038a6449476ec62250b223e106b0cd29bdd29ba15.jpg) +Model Architecture MaskCLIP Ope +XPM + +As CLIP models are trained contrastively at the global image-text level, they do not directly output segmentation maps at the pixel or region level. Recent works [9, 13, 55] demonstrate the feasibility of adopting and locking a pretrained CLIP model for open-vocabulary image segmentation by adopting a two-stage approach, which first generates class-agnostic mask proposals and subsequently classifies each mask region based on a CLIP model. + +This decoupled two-stage design, involving localization and then classification, is considered advantageous for open-vocabulary universal segmentation. First, it does not depend on any task specificity. Recent works [7, 8] have attempted to unify instance, semantic, and panoptic segmentation through Transformer-based architectures [6], and the CLIP-based region classification module itself is directly applicable to different types of masks (instance/semantic). Second, it is a natural choice to utilize CLIP models exclusively for object/scene classification rather than localization. The reason is that the dense features within a CLIP visual encoder only carry semantic information, but can- + +not discriminate between different objects belonging to the same category. + +However, recent works [9, 20] still exhibit limitations with regard to being open-world. Specifically, the class-agnostic mask proposal network is trained only on the supervision of a limited set of base classes, which restricts its ability to generate mask proposals beyond supervision. Hence, the model performance is hindered when dealing with novel or unseen categories. In addition, although previous works have attempted to introduce some additional modules for mask classification, they fail to fully bridge the gap between image-level and region-level representation, thus lacking in adaptation to mask classification. The balance between maintaining generalization for more categories and adapting CLIP models for mask classification tasks needs further exploration. + +In this paper, we aim to conquer these weaknesses. We introduce a new approach called MasQCLIP that can perform open-vocabulary instance, semantic, and panoptic segmentation under a single framework. To accomplish this, MasQCLIP uses a similar two-stage model design: 1) a mask generator stage that extracts object/scene masks, and 2) an encoder-only module that performs mask classification. We are also inspired by the Mask Class Token strategy from MaskCLIP [9], which is tightly integrated with a given CLIP model. MasQCLIP is different from MaskCLIP [9] in two key areas: 1) the use of a student-teacher self-training module that significantly enhances the generation of novel class masks, and 2) fine-tuning the query parameters in the CLIP visual encoder, which better adapts the CLIP models for mask region representations. The following are the contributions of our work: + +- We develop MasQCLIP for open-vocabulary universal image segmentation that demonstrates substantial performance improvement over the current state-of-the-art methods by a large margin across all three tasks including open-vocabulary instance, semantic, and panoptic segmentation. +- We design a progressive distillation process to generate more novel mask proposals beyond supervision, thus taking a step forward toward open-world mask generation. +- We propose a parameter-efficient fine-tuning strategy, MasQ-Tuning, which only tunes the query parameters. When coupled with Mask Class Tokens, MasQ-Tuning is able to preserve the generalization of a pre-trained image-level CLIP model while greatly enhancing its adaptation for segmentation tasks. + +# 2. Related Work + +Being universal Traditional image segmentation methods can be roughly divided into three groups: 1) instance seg + +mentation [14], 2) semantic segmentation [36, 39], and 3) panoptic segmentation [22, 40]. Panoptic segmentation essentially integrates instance and semantic segmentation, but a careful algorithm design is needed [22, 45] to achieve the goal, as instance segmentation is object-centered whereas semantic segmentation is per-pixel based. The introduction and adaptation of Transformers [41] to the object detection task, Detection Transformers [6], also makes the unification of instance and semantic segmentation feasible. In particular, the Mask2Former method [7] unifies background stuff and foreground things under the query token representation by designing a Transformer-based architecture for closed-set universal image segmentation. + +Being open-world Since it is a relatively new topic, there lacks a commonly accepted definition for being "open-world". There exists different terms such as zero-shot [3], open-set [19], and open-vocabulary [50]. It is gradually accepted that the open-vocabulary setting has the best alignment with the general open-world expectation where the target of interest to be extracted can be freely specified using a natural language description during inference. + +Open-Vocabulary Detection and Segmentation Various open-vocabulary vision algorithms have been developed. A rough summary for the comparison of existing methods can be seen in [9]. Broadly speaking, there exist methods for open-vocabulary object detection [5, 13, 24, 49, 50], instance segmentation [13, 18], semantic segmentation [12, 23, 46, 58], and panoptic segmentation [9]. Previous works [27, 30, 35, 44, 49, 55] mainly focus on knowledge distillation from an existing CLIP model, but our method integrates CLIP models rather than performing distillation from CLIP models. Some recent works [32, 58] have also attempted to extract dense features from CLIP models to represent pixelwise features. + +Knowledge Distillation Knowledge Distillation [17] has been proposed to extract knowledge from the teacher model to the student model. It is called self-distillation [52] when both teacher and student models adopt the same model architecture. For the image segmentation task, self-training with pseudo labels has been proposed to improve the quality of predicted masks in self-supervised learning [28, 43] and semi-supervised learning [42, 47, 48]. We use a similar strategy but focus on self-distilling novel mask proposals from the teacher model. + +Fine-tuning Fine-tuning aims to efficiently utilize knowledge from large models for downstream tasks. In terms of ConvNet [15, 37], many fine-tuning strategies have been proposed, including bias tuning [4], side tuning [51], and residual adapter [33]. After Transformer [41] is introduced into the field of computer vision, several fine-tuning methods have been proposed for ViT [10]. Recent works have + +![](images/286be5ea722844ac01a391d1554ced57959d95b3c34a691e1d2f2d426a5c0e78.jpg) +Figure 2: Overview of MasQCLIP. MasQCLIP consists of a class-agnostic mask proposal network and a mask classification module based on CLIP. In the mask proposal network, we apply progressive distillation to segment masks beyond base classes. Please refer to Fig. 3 for more details. After we obtain an open-world mask proposal network, the predicted masks are then sent to the classification module to obtain labels. To efficiently utilize the dense CLIP features, we propose MasQ-Tuning. We set new query projections $f_{Q}^{\prime}$ for the Mask Class Tokens to obtain optimal attention weights, and $f_{Q}^{\prime}$ at each layer are the only learnable parameters. + +explored subspace training [16] for low-dimensional reparameterization and prompt tuning [21, 34] for adaptation. In terms of CLIP models, [38, 53] insert adapters into pretrained CLIP models, and DenseCLIP [32] uses CLIP parameters as initialization for segmentation tasks. However, existing works mainly make use of the pre-trained models for a specific dataset, and they do not fully exploit the intrinsic generalization ability in pre-trained models. + +# 3. Preliminary + +MaskCLIP [9] adapts the CLIP model for segmentation tasks through a two-stage pipeline. Specifically, a class-agnostic mask proposal network first generates candidate masks, then MaskCLIP utilizes dense CLIP features to classify each mask proposal with a corresponding Mask Class Token. Mask Class Tokens are initialized with the class token in the CLIP visual encoder, then are appended alongside the original CLIP tokens (image tokens and a class token). Mask Class Tokens extract features from CLIP tokens through the masked cross-attention mechanism where mask proposals also serve as attention masks, i.e., + +$$ +\operatorname {C r o s s A t t n} (\cdot) = \operatorname {s o f t m a x} \left(Q _ {\text {m a s k}} K _ {\text {i m g}} ^ {T} + \mathcal {M} _ {\text {m a s k}}\right) \cdot V _ {\text {i m g}}, \tag {1} +$$ + +$$ +Q _ {\text {m a s k}}, K _ {\text {i m g}}, V _ {\text {i m g}} = f _ {Q} \left(x _ {\text {m a s k}}\right), f _ {K} \left(x _ {\text {i m g}}\right), f _ {V} \left(x _ {\text {i m g}}\right). \tag {2} +$$ + +Here, $x_{\mathrm{mask}} \in \mathbb{R}^{m \times C}$ , $x_{\mathrm{img}} \in \mathbb{R}^{p \times C}$ denote $m$ Mask Class Tokens and $p$ CLIP tokens respectively, and $f_{Q}, f_{K}, f_{V}$ denote the projections for query, key, and value respectively. In MaskCLIP, $f_{Q}, f_{K}, f_{V}$ are frozen to maintain generalization. The attention mask $\mathcal{M}_{\mathrm{mask}} \in \mathbb{R}^{m \times p}$ is derived as + +$$ +\mathcal {M} _ {\text {m a s k}} (i, j) = \left\{ \begin{array}{l l} 0 & \text {i f i - t h m a s k f a l l s i n j - t h p a t c h} \\ - \infty & \text {o t h e r w i s e} \end{array} . \right. \tag {3} +$$ + +The final classification scores are the dot product between Mask Class Tokens and the language descriptors from the CLIP language encoder. + +# 4. Methods + +# 4.1. Problem Setting + +During training, the model is only provided with a set of images and their annotations on base classes $C_B$ . We denote the training dataset as $\mathcal{D}_B = \{(I_i, \mathcal{Y}_i)\}_{i=1}^N$ . Each annotation $\mathcal{Y}_i$ contains ground-truth masks $\mathcal{Y}_i^M$ and their labels $\mathcal{Y}_i^L$ on base classes in image $I_i$ . In the inference stage, we evaluate our model on another set of images with a new set of novel classes $C_N$ , and the testing dataset is denoted as $\mathcal{D}_N$ . According to the relationship between $\mathcal{D}_B$ and $\mathcal{D}_N$ , previous works mainly use two settings: + +- Cross-dataset. $\mathcal{D}_B$ and $\mathcal{D}_N$ are different datasets, and class sets $C_B$ and $C_N$ may overlap. +- Base-novel. $C_B$ and $C_N$ are disjoint, i.e., $C_B \cap C_N = \varnothing$ . Under this setting, the same dataset, such as COCO [25], is used during training and testing. + +In our paper, we evaluate our proposed algorithm on both of the above settings. + +![](images/e49f49ec6be19ff7cf4257afd6fc71beabf1f2a0feeb73371f184289ae8c6f5d.jpg) +Figure 3: Detailed interpretation of progressive distillation. We select high-quality mask proposals with novel concepts from the inference results of the teacher model as extra annotations. These extra annotations are then distilled into the student model to encourage generalization. This process is performed iteratively. + +# 4.2. Proposed Method + +# 4.2.1 Progressive Distillation for Mask Generation + +Object Score. In experiments, we observe that MaskCLIP [9] does not consistently assign higher confidence to mask proposals that align more accurately with ground-truth masks. Therefore, we incorporate a binary classification head to the class-agnostic mask proposal network in our MasQCLIP. The resulting object score, denoted as $p_{\mathrm{obj}} \in \mathbb{R}$ , estimates the quality of mask proposals. During inference, the final classification score for the $i$ -th class is determined by $p_{\mathrm{cls}}^{(i)} = p_{\mathrm{obj}} \cdot p_{\mathrm{clip}}^{(i)}$ . Here, $p_{\mathrm{clip}}^{(i)}$ represents the score for the $i$ -th class obtained from the mask classification module, which will be further discussed in Sec. 4.2.2. + +If training is conducted with annotations from both base classes $C_B$ and novel classes $C_N$ , the object score can serve as a general indicator of mask quality. However, when supervision is only provided on $C_B$ , the object score is more reflective of the quality of base masks, leading to bias toward $C_B$ . But we will show in Sec. 5.4.1 that incorporating object scores still boosts performance on both $C_B$ and $C_N$ by a clear margin. Hence, it is still reasonable and effective to incorporate object scores for all mask proposals. + +Progressive Distillation. To develop an open-world mask proposal network capable of generating masks beyond base classes $C_B$ , we propose a progressive distillation strategy. By utilizing the object score as an indicator of mask quality, we can filter high-quality mask proposals that do not overlap with mask annotations of $C_B$ , thus producing extra annotations for training. By iteratively repeating this distillation process, the network will be able to segment more concepts progressively and eventually be open-world. + +Specifically, we initialize the teacher model $\mathcal{T}_{\mu}$ with the mask proposal network trained on the base annotations $\mathcal{D}_B^{\prime} = \{(I_i,\mathcal{Y}_i^M)\}_{i = 1}^N$ without class labels. To produce extra supervision for the student model $\mathcal{T}_{\theta}$ on image $I_{i}$ , we first obtain inference result $\mathcal{T}_{\mu}(I_i)$ from the teacher model. + +Algorithm 1 Progressive Distillation +Require: Initial teacher model $\mathcal{T}_{\mu}$ with parameter $\mu$ +Require: Dataset $\mathcal{D}_B' = \{(I_i, \mathcal{Y}_i^M)\}_{i=1}^N$ (only masks) +Require: Score threshold $\alpha$ , IoU threshold $\beta$ +for $K$ iterations do + $\theta \gets \mu$ ▷ Initialize the student model $\mathcal{T}_{\theta}$ +for $(I_i, \mathcal{Y}_i^M)$ in $\mathcal{D}_B'$ do + $\mathcal{Y} \gets \mathcal{Y}_i^M$ ▷ $\mathcal{Y}$ : supervision for $\mathcal{T}_{\theta}$ $\hat{\mathcal{Y}} = \mathcal{T}_{\mu}(I_i)$ +for $\hat{y}$ in $\hat{\mathcal{Y}}$ do +if $\forall y \in \mathcal{Y}, IoU(\hat{y}, y) < \beta$ then +if score( $\hat{y}$ ) > $\alpha$ then + $\mathcal{Y} \gets \mathcal{Y} \cup \{\hat{y}\}$ $L_{\theta} = \mathcal{L}(\mathcal{T}_{\theta}(I_i), \mathcal{Y})$ $\theta \gets \theta - \gamma \nabla_{\theta}(L_{\theta})$ $\mu \gets \theta$ ▷ Update the teacher model $\mathcal{T}_{\mu}$ + +Then we select mask proposals with high object scores that are non-overlap with ground-truth masks in $\mathcal{Y}_i^M$ . These selected masks are considered novel masks and combined with $\mathcal{Y}_i^M$ to form the supervision $\mathcal{V}$ for the student model. To further boost generalization, we train the student model progressively by updating the parameters of the student model to the teacher model iteratively. A more detailed algorithm is presented in Alg. 1. Experiments show that our algorithm works surprisingly well. + +# 4.2.2 MasQ-Tuning + +Given masks produced by the class-agnostic mask proposal network, we expect to classify each mask region using pretrained CLIP models. To maintain the generalization ability of CLIP models, MaskCLIP [9] freezes all CLIP parameters and appends auxiliary tokens for region classification. According to Eq. (1), for each Mask Class Token $x_{\mathrm{mask}}^{(i)} \in \mathbb{R}^C$ , we have its query embedding $q_i = f_Q(x_{\mathrm{mask}}^{(i)})$ and attention weight over $p$ CLIP tokens, $\text{softmax}(q_i K_{\mathrm{img}}^T + \mathcal{M}_i) \in \mathbb{R}^p$ . The attention weight indicates $x_{\mathrm{mask}}^{(i)}$ where to focus, and $V_{\mathrm{img}}$ is interpreted as the dense CLIP features that all Mask Class Tokens can extract. + +MaskCLIP preserves the original feature space of CLIP by freezing all parameters, however, it lacks in adaption. Although the appended Mask Class Tokens perform classification similar to the class token in CLIP, there is still a shift between them. Specifically, each Mask Class Token is intended to classify a mask region in an image, while the original class token is designed to extract image-level feature. To enhance adaptation ability, we propose applying new query projections $f_{Q}^{\prime}$ to each cross-attention layer for + +Mask Class Tokens, i.e., + +$$ +\operatorname {C r o s s A t t n} (\cdot) = \operatorname {s o f t m a x} \left(\mathbf {Q} _ {\text {m a s k}} ^ {\prime} K _ {\text {i m g}} ^ {T} + \mathcal {M} _ {\text {m a s k}}\right) \cdot V _ {\text {i m g}}, \tag {4} +$$ + +$$ +\mathbf {Q} _ {\text {m a s k}} ^ {\prime}, K _ {\text {i m g}}, V _ {\text {i m g}} = \mathbf {f} _ {\mathbf {Q}} ^ {\prime} \left(x _ {\text {m a s k}}\right), f _ {K} \left(x _ {\text {i m g}}\right), f _ {V} \left(x _ {\text {i m g}}\right). \tag {5} +$$ + +In this way, Mask Class Tokens obtain better attention weights through learning. In addition, since the softmax operator in Eq. (4) serves as a normalizer, the results of Eq. (4) still lie in the sub-space spanned by rows of $V_{\mathrm{img}}$ . $V_{\mathrm{img}}$ is projected from CLIP tokens and thus preserves the knowledge of CLIP. Therefore, MasQ-Tuning is able to improve adaptation while maintaining generalization. + +To effectively inherit the knowledge and the statistics of CLIP, other layers (layernorm, FFN, and the final projection) are frozen during fine-tuning. + +Losses. Our goal is to match the appended Mask Class Tokens with their corresponding ground-truth labels, so we use the dot-product between Mask Class Tokens and language descriptors as scores and compute cross-entropy loss, i.e., + +$$ +\mathcal {L} _ {\mathrm {c l s}} = - \log \left(\frac {\exp \left(s _ {y}\right)}{\sum_ {i} \exp \left(s _ {i}\right)}\right). \tag {6} +$$ + +where $s_i$ denotes the score for $i$ -th class and $y$ is the assigned label for the mask. If a predicted mask is matched to a ground-truth mask according to an IoU threshold, we then assign the mask a label. Otherwise, we use a fixed word, "background", as the label for the predicted mask. + +# 5. Experiments + +We evaluate MasQCLIP on three segmentation tasks to demonstrate its effectiveness and universality, and we follow the commonly-used settings in different segmentation tasks. For instance segmentation, we use base-novel setting following [18]. For semantic and panoptic segmentation, we use cross-dataset setting following [9, 13]. We show MasQCLIP achieves state-of-the-art results on all benchmarks with a universal architecture. We also conduct ablation studies to verify our proposed method. + +# 5.1. Datasets and Evaluation Metrics + +COCO. In base-novel setting, we use instance segmentation annotations of COCO [25]. Following [18], we partition COCO annotations into 48 base classes for training and 17 novel classes for evaluation. There are 108k training images and 5k validation images. In cross-dataset setting, we use panoptic segmentation [22] annotations of COCO for training, which include 80 thing classes (foreground) and 53 stuff classes (background). There are 118k training images and 5k validation images. + +ADE20k. ADE20k [56, 57] serves for semantic segmentation and panoptic segmentation evaluation under cross-dataset setting. There are 2k validation images in total. The + +full version (A-847) includes 847 classes and the short version (A-150) includes 150 classes. + +PASCAL-Context. Pascal-Context [29] serves for semantic segmentation evaluation under cross-dataset setting. There are 5k validation images in total. The full version (P-459) includes 459 classes and the short version (P-59) includes 59 classes. + +Evaluation Metrics. For instance segmentation, we report $mAP$ (mean average precision) [25] at IoU (intersection-over-union) of 0.5 following base-novel setting [1, 18, 50]. For semantic segmentation, we report $mIoU$ (mean intersection-over-union) [11] for evaluation. For panoptic segmentation, we report $PQ$ (panoptic quality) [22]. + +# 5.2. Implementation Details + +Class-Agnostic Mask Proposal Network. We train Mask2Former [7] or Mask R-CNN [14] with ResNet-50 backbone to generate class-agnostic mask proposals. The labels of masks are not used as supervision, and the number of mask proposals for each image is set to 100 for both models. In Mask2Former, the number of classes is set to 1 to obtain the object score. In Mask R-CNN, we adopt the confidence scores of the RPN head as object scores. The default experiment setting for Mask R-CNN is R50-FPN-1x. + +Progressive Distillation. For Mask2Former, we first train the initial teacher model until convergence. Then, we retrain the student model for 2 rounds with 30k iterations each round (under both settings). Unless stated, other experiment settings are set to default as training Mask2Former [7]. For Mask R-CNN, we use the checkpoint of R50-FPN-1x as the initial teacher model. We then re-train the student model for 2 rounds with 10k iterations each round (under both settings). For all models and settings, we set the threshold of object scores $\alpha$ to 0.8, and the NMS threshold $\beta$ to 0.1. + +MasQ-Tuning. During fine-tuning, we use the same CLIP model ViT-L/14@336px as in [9]. The language descriptors are simply the text embeddings of category names given by the language encoder of CLIP without any prompt. The number of Mask Class Tokens is set to 100 which is equivalent to the number of mask proposals. The query projection $f_{Q}^{\prime}$ at each layer exhibits the same architecture of a linear projection as the original $f_{Q}$ in CLIP visual encoder. In both cross-dataset and base-novel settings, we use AdamW [26] as our default optimizer and the initial learning rate is set to 0.0001. We assign a predicted mask a label if it has an IoU higher than 0.6 with a ground-truth mask. We fine-tune for 10k iterations with a batch size of 4, and the learning rate is decreased by a factor of 10 at 9k iterations. During inference, the post-processing follows Mask2Former after obtaining labels for mask proposals. + +Settings. For each model architecture (Mask R-CNN or Mask2Former), we train two MasQCLIP models for base- + +
MethodsBackboneInstanceSemanticPanoptic
BaseNovelAllA-150A-847P-59P-459PQ\( PQ^{th} \)\( PQ^{st} \)
XPM [18]ResNet-5041.521.636.3-------
LSeg+ [23]EffNet-B7---18.03.846.57.8---
OpenSeg [12]EffNet-B7---21.16.342.19.0---
MaskCLIP (Mask R-CNN) [9]ResNet-50---22.46.841.39.112.911.216.1
MaskCLIP (Mask2Former) [9]ResNet-50---23.78.245.910.015.113.518.3
MasQCLIP (Mask R-CNN)ResNet-5040.728.437.523.78.444.414.114.914.515.6
MasQCLIP (Mask2Former)ResNet-5051.031.946.030.410.757.818.223.321.227.7
+9.5+10.3+9.7+6.7+2.5+11.3+8.2+8.2+7.7+9.4
+ +Table 1: Results on open-vocabulary universal image segmentation. We compare MasQCLIP with state-of-the-art models on three segmentation tasks with a universal architecture. We use Mask R-CNN or Mask2Former as our class-agnostic mask proposal network. All methods in the table rely only on COCO dataset for training. a) For instance segmentation, we report mask AP50 following base-novel setting [18]. b) For semantic segmentation, we report mIoU on ADE20k and PASCAL-Context following cross-dataset setting [20]. A-150 and A-847 represent ADE20k with 150 classes and 847 classes respectively. P-59 and P-459 represent PASCAL-Context with 59 classes and 459 classes respectively. c) For panoptic segmentation, we report $PQ$ on ADE20k following cross-dataset setting [9]. We achieve significant improvements on all evaluation metrics. + +
MethodsConstrainedGeneralized
BaseNovelBaseNovelAll
OVR [50]42.020.941.617.135.2
SB [1]41.620.841.016.034.5
BA-RPN [54]41.820.141.315.434.5
OVR+OMP [2]31.314.130.58.324.7
XPM [18]42.424.041.521.636.3
MasQCLIP (Mask R-CNN)40.930.140.728.437.5
MasQCLIP (Mask2Former)51.234.351.031.946.0
+ +Table 2: Results on open-vocabulary instance segmentation. We report mask AP50 in the table. The results presented in the table all use the ResNet-50 backbone. Constrained setting means that the model is evaluated on either base classes or novel classes separately. Generalized setting means that the model is tested jointly on both base and novel classes. Notice that the results of novel classes show the generalization ability of models. + +novel and cross-dataset settings separately. The former model is trained on base classes of COCO-instance dataset and is tested on novel classes (for instance segmentation), while the latter is trained on the COCO-panoptic dataset and is used for both semantic (through post-possessing) and panoptic segmentation evaluation. + +# 5.3. Main Results + +Instance Segmentation. We evaluate our MasQCLIP on instance segmentation under base-novel setting. We first train MasQCLIP on base classes of COCO-instance dataset and then evaluate the model on novel classes. The detailed results are presented in Tab. 2. As shown, when using Mask R-CNN as our class-agnostic mask proposal network, we achieve an improvement of 6.8 AP50 on novel classes over XPM [18]. When using Mask2Former, we further achieve an improvement of 10.3 AP50. The evaluation metrics on novel classes mainly reflect the generalization ability of models. Since our relative improvement on novel classes is much higher than that on base classes across two mask proposal networks, our proposed method enjoys better gen + +eralization ability compared to previous works. + +Semantic Segmentation. We evaluate our MasQCLIP on semantic segmentation under cross-dataset setting. We directly use the model trained on COCO-panoptic dataset for evaluation, and report the results on ADE20ksemantic and PASCAL-Context-semantic datasets in Tab. 1. In terms of $mIoU$ , MasQCLIP improves previous state-of-the-art results by 6.7, 2.5, 11.3, and 8.2 on A-150, A-847, P-59, and P-459 datasets respectively. + +Panoptic Segmentation. We evaluate our MasQCLIP on panoptic segmentation under cross-dataset setting. We first train MasQCLIP on COCO-panoptic dataset, and then directly evaluate the model on ADE20k-panoptic dataset. The results are presented in Tab. 1. As shown, when using the same mask proposal network architecture, MasQCLIP outperforms state-of-the-art MaskCLIP [9] by $8.2PQ$ . Even adopted with a weaker mask proposal network of Mask R-CNN, MasQCLIP still achieves on-par results on $PQ$ compared with MaskCLIP. + +# 5.4. Ablation Studies + +# 5.4.1 Progressive Distillation + +In this section, we conduct ablation studies on progressive distillation. We evaluate the models on instance segmentation under base-novel setting. The initial teacher model is trained for 100k iterations on base annotations, and the student model is then re-trained for 30k iterations each round using the initial teacher model. + +Object Scores. We first study the importance of object scores. As shown in Tab. 3, incorporating object scores boosts performance on base classes and novel classes significantly. In addition, despite object scores being trained only on base classes, they still serve as reliable indicators of mask quality for novel classes, which demonstrates the generalization of object scores. The results show that it is + +![](images/313b2598d8e2a93ef81219129097882bc911056c80d7f9e561f337e1827356ea.jpg) + +![](images/e0a89c9733dc265e7db936459ae396452221a8c27c925d77f123b0e9c59fc333.jpg) +Input + +![](images/54317b5d8c1e37f4a15068dca94d6f7e13f44ebcf8154bf3f679c8596757d0f4.jpg) + +![](images/3208962849aacd0762c7b8e43731159c023146899a265dad3b439e528045c51d.jpg) +CLIP Baseline +Figure 4: Comparison on open-vocabulary instance segmentation. We evaluate on the same set of images as in MaskCLIP [9]. The above two images are from ADE20k dataset. Visualization results show that our mask proposals are more robust and high-quality. + +![](images/572f3d55c09644ae6cd336af6ac07b736837baf2c4874ebe1959c08ed61ff70b.jpg) + +![](images/9034916a48c684023c3344336d5543641ddbb23bc8173796a8d551336229689d.jpg) +MaskCLIP + +![](images/2e780436b55f5dacb84bf19b4ff34962246516e3544187e181bc99d60a18b2d9.jpg) + +![](images/85ac3f211955747f2d606f5a8df7bcea7ef09ca40c580bfcc77655624680a025.jpg) +MasQCLIP + +
ModelsScoresBaseNovelAll
Mask2Former-16.911.315.4
Mask2Former✓53.822.645.6
+ +Table 3: Ablations on Object Scores. We report mask AP50 in the table. Models denote the architecture of class-agnostic mask proposal networks. Scores denote whether we incorporate object scores. + +
TeacherStudentBaseNovelAll
100k-53.822.645.6
100k30k×150.626.144.2
100k30k×251.031.946.0
100k30k×351.231.246.0
200k-54.718.245.1
+ +reasonable to consider object scores as a general indicator of mask quality. + +Iterative Re-training. Tab. 4 shows the effectiveness of progressive distillation. After we train the student model for 2 rounds progressively, the model performance improves on novel classes by 9.3 AP50. Although the results manifest a slight performance drop on base classes, it can be explained that the model is balancing between the base and extra (novel) annotations, thus leading the model to be less overfitted on base classes. + +If we continue to train the student model for more rounds (e.g. 3 rounds), the model does not gain further improvement in generalization ability, indicating that there might exist an upper bound for the progressive distillation process. In addition, we also show that the improvement on novel classes cannot simply gain from a longer training schedule. When training the network for another 100k iterations without progressive distillation, there is a notable performance + +Table 4: Ablations on Iterative Re-training. We report mask AP50 in the table. We adopt the Mask2Former architecture and incorporate object scores by default. Teacher denotes the training iterations of the initial teacher model, and Student denotes how we train the student model progressively. + +
MethodsQKVAllParamADE20kCOCO
PQmIoUPQmIoU
Freeze-----10.715.719.422.1
Tune-V--✓-25M14.418.050.063.2
Tune-QKV✓✓✓-75M14.918.650.563.5
Tune-CLIP✓✓✓✓304M14.718.349.063.6
Tune-K-✓--25M22.529.848.361.6
Tune-QK✓✓--50M22.930.149.062.3
Tune-Q (ours)✓---25M23.330.448.562.0
+ +Table 5: Ablations on MasQ-Tuning. We try different fine-tuning strategies. $Q, K, V$ means the newly added query, key, and value projections for Mask Class Tokens respectively, and All means all the newly added parameters (also including layernorm, FFN, and the final projection). Param denotes the total number of trainable parameters. The models are first trained on COCO and then evaluated on ADE20k. We note that the metrics on ADE20k mainly show the generalization ability. + +drop of 4.4 AP50 (from 22.6 to 18.2) on novel classes. Our observation supports that improvement of model performance indeed comes from progressive distillation. + +# 5.4.2 MasQ-Tuning + +To validate our fine-tuning method, MasQ-Tuning, we build several baselines to prove its effectiveness. + +- Freeze: Same as the MaskCLIP w/o RMA baseline in [9]. We incorporate object scores during inference. +- Tune-Q: Only query projections $f_{Q}^{\prime}$ for Mask Class Tokens are learnable during fine-tuning. Notice that MasQCLIP adopts this fine-tuning strategy. +- Tune-K: Only key projections $f_{K}^{\prime}$ for Mask Class Tokens are learnable during fine-tuning. +- Tune-V: Only value projections $f_V'$ for Mask Class Tokens are learnable during fine-tuning. +- Tune-QK: Query and key projections for Mask Class Tokens ( $f_{Q}^{\prime}$ and $f_{K}^{\prime}$ ), are learnable during fine-tuning. +- Tune-QKV: Query, key, and value projections for Mask + +![](images/29e008b61647159925c30af0ffcc4d05b79eb02dd04c4bdccf4cb4b71dccc4e9.jpg) +Image + +![](images/c9ee995dd2f5f6cd624bc90b42f9c8795fd83b747eb8b1c1d655b73ced7394a3.jpg) +GT + +![](images/422cac3ac5120310d831aa4bb764aedc65d05a7e53068950b0f06290d41666ef.jpg) +house + +![](images/ed4b982c7f9fefc00ff85cb98088f945140039c89882a4c38735aa4f66417545.jpg) +sky + +![](images/49d16f5694885bde193c79b80dea69cf70b010cd617cf4fa43322100ca33c03e.jpg) +grass + +![](images/3c2f713d9f68e5ab6f0e1e8f31fb6f2656fd4268153f2952262a1cf7b912a135.jpg) +land + +![](images/31aebb737ea92b16ef61f274aefa707f46dd53e5ee69a417188e38d8f1912c95.jpg) +OpenSeg + +![](images/c62cfde2fdd1b598da2edb3d8e9bdaa2d327f5111dd905ee30a085df749e0c51.jpg) +tree + +![](images/14c9ed297be81d46341daade677991558b74bd8fa70f8538ff260f73bfd733ed.jpg) +brick + +![](images/4767cb8d94d69026d060968c9e94fbdad6e1875cd20f7a9a07ce64f282666896.jpg) +ock + +![](images/dae54618c3189131fa900dd38c9e3c11a70ac4964b8bc16101c92cfba907e167.jpg) +river + +![](images/5a6ffaf4dc89589dc4117b50e80f759f33865dcb0be9887b9b1d99843fe8af41.jpg) +MaskCLIP + +![](images/90077c89a02487a4c495d86a97598ae827e51329031f219f73eecee02dd4980b.jpg) +wall + +![](images/9aae7d2abfecf5281161ab17e99d0b777f0bda5d5c7dfc7050930dc2d0d2501e.jpg) +building + +![](images/983d8498e627fdbb9ab465ed7b2474086d52a205df4853d91058b4432c7ed43d.jpg) +roo + +![](images/da3d4621a4abc798c79151be251343545a3a1620ca1b6dcd21390e1be7fd8580.jpg) +MasQCLIP + +![](images/97928c55d8cbe9b776bb180a205e23042a648defae7a248d86f12ab8d450c640.jpg) +window + +![](images/b7307c8780ef94a70b5d463f3e2f98eb823853f7020cfd1845f69a477d00bc82.jpg) +Figure 5: Comparison on open-vocabulary semantic segmentation. We evaluate on the same image as in OpenSeg [12]. Notice that MasQCLIP successfully recognizes the windows on the house, demonstrating that MasQCLIP is able to classify small objects. + +![](images/9e906a0338cc8efe347b91a36e14765fe17f0f1ec960b13b55f13c21b44e47ae.jpg) + +![](images/ffa5867664025190cee55d6cffde3d2da2df1f17a30f53280ab23a538d2a0180.jpg) +Figure 6: Comparison on open-vocabulary panoptic segmentation. We evaluate on the same set of images as in MaskCLIP [9]. The images are from ADE20k dataset. Visualization shows that MasQCLIP produces higher-quality masks and has higher classification accuracy. + +![](images/a6f63e171f507d10239d612c33d0af68ef693e49a6b25c2756a25f53341fd716.jpg) + +![](images/0227ced23a31af289f392e852ec6a923c8f1c0cefb42f78262fced6834a68dfd.jpg) + +![](images/8a47267291f7bd91033207411f1ac4af2377f3ca3ea25165ed7c34e704ca6267.jpg) + +![](images/8e52a2530dd8eb1afbd2cecb51224354601da450001b90d343da26bbe5347c39.jpg) + +![](images/a8ff2ddb5dbce34e240090c2876274c780440a8d6069df6d3f172d213c6bbcb4.jpg) + +![](images/c222dbd78a250ae4ab504af02fa7aaa676cff9c4d67813d2a1da150e1e64526b.jpg) + +Class Tokens $(f_{Q}^{\prime}, f_{K}^{\prime}$ , and $f_{V}^{\prime}$ ), are learnable during fine-tuning. + +- Tune-CLIP: A new set of CLIP parameters is learned during fine-tuning, and masked-cross attention is performed between Mask Class Tokens and CLIP tokens. We use CLIP parameters as initialization. + +In this ablation study, we test the models on semantic and panoptic segmentation under cross-dataset setting. We use the same class-agnostic mask proposal network for all models, and then fine-tune the mask classification module based on the predicted masks. Training settings are all kept the same. Our results are shown in Tab. 5. + +Adaptation. We compare the evaluation metrics of the above methods on COCO dataset to show the strong adaptation ability of MasQ-Tuning. Compared to Freeze with 19.4 + +$PQ$ and 22.1 mIoU on COCO, Tune-Q has a significant improvement of 29.1 $PQ$ (from 19.4 to 48.5) and 39.9 mIoU (from 22.1 to 62.0) respectively. This shows that the improvement on adaptation ability should be credited to those learnable query projections $f_{Q}^{\prime}$ for Mask Class Tokens. In addition, compared to Tune-CLIP with 49.0 $PQ$ and 63.6 mIoU on COCO, Tune-Q has much fewer learnable parameters, but only has little performance drop (-0.5 $PQ$ and -1.6 mIoU). This indicates that simply adding more parameters is not helpful, and our proposed MasQ-Tuning has achieved impressive adaptation ability. + +Generalization. We now focus on the performance of the above methods on ADE20k dataset to show the strong generalization ability of MasQ-Tuning. When adding learnable value projections $f_V'$ for Mask Class Tokens, the model cannot generalize well to ADE20k dataset. Compared to + +![](images/5fa77b82f5b728cdfc8c9d9dc1ad6ee25ef98f5cd221d30d859a7f1c47c1c0e2.jpg) + +![](images/180b1eefdf780a8db901004209e282444b0d65137219005fedfedd22caca7c57.jpg) +(a) "a black cat", "an orange cat" + +![](images/e8b4b26ec7b8039f10ff1713e81154076fc8ba049fc4afef8f79f78d39a0a462.jpg) + +![](images/f06f9eb282f5a372a7680567b9af3f746863c1168ac85846a392a6a0ad5fa12f.jpg) +(b) "beer", "wine" +Figure 7: User-specified segmentation. We use the model trained on COCO-panoptic for evaluation. Visualization results show that our model can distinguish subtle differences among objects. + +![](images/07a0426558e65ae0c540d3e5498ca62d395a5db31f364e99cb6f56e5db4574e5.jpg) + +![](images/9b6e5755d00e48243b8ad56079806a8689750bb777bb6573a2f37fd5e91d92b2.jpg) +(c) "an adult", "a child" + +Tune-Q with 23.3 PQ, Tune-V, Tune-QKV and Tune-CLIP have a performance drop of 8.9, 8.4, and 8.6 on $PQ$ respectively. This proves the importance of freezing $V_{\mathrm{img}}$ which is interpreted as dense CLIP features. By inheriting $V_{\mathrm{img}}$ from the CLIP model, MasQCLIP is able to preserve the original feature space within CLIP. Compared to Tune-QK, Tune-Q reaches better performance on ADE20k and is more parameter-efficient, where only $8.2\%$ of original parameters in CLIP visual encoder are added for training. Therefore, we choose Tune-Q as the fine-tuning strategy of MasQCLIP. + +# 5.5. Qualitative Results + +In this section, we compare the visualization results of MasQCLIP with previous models [9, 12]. The results of instance, semantic, and panoptic segmentation are presented in Fig. 4, Fig. 5, and Fig. 6 respectively. For a fair comparison, We all use the same set of images as previous works [9, 12]. We observe from the visualization results that MasQCLIP produces more robust mask proposals and enjoys a higher mask classification accuracy, which corresponds to our two key components proposed in MasQCLIP. As shown in Fig. 7, MasQCLIP exhibits the ability to segment objects of arbitrary classes as per user specifications and to discriminate between subtle distinctions within them (e.g. "beer" vs. "wine", "child" vs. "adult"). + +# 5.6. Efficiency + +MasQCLIP exhibits great capability in open-vocabulary universal segmentation while being computationally efficient at the same time. We report the results of GFLOPs in Tab. 6. As shown, the GFLOPs of MasQCLIP is only $14.5\%$ higher than the combined GFLOPs of Mask2Former and CLIP visual encoder, and is $34.1\%$ lower than the GFLOPs of MaskCLIP. + +
ModelsGFLOPs
Mask2Former [7]78.9
CLIP Visual Encoder [31]233.0
MaskCLIP† [9]542.0
MasQCLIP (ours)357.2
+ +Table 6: Model efficiency. The resolution of input images is set to $640 \times 640$ for Mask2Former and $336 \times 336$ for CLIP Visual Encoder. We use the CLIP model ViT-L/14@336px. $\dagger$ means our re-implement according to the paper (no public codes available). + +# 6. Conclusions + +We propose a two-stage model, MasQCLIP, for open-vocabulary universal segmentation. We first design a progressive distillation process for the class-agnostic mask proposal network to segment open-world masks. Additionally, we adapt CLIP models for mask (region) classification while maintaining the generalization ability of CLIP through our proposed MasQ-Tuning method. We achieve state-of-the-art results with substantial improvement over the existing approaches across three open-vocabulary tasks including instance, semantic, and panoptic segmentation. + +Limitations. Since MasQCLIP is built on top of a pretrained CLIP model, though fine-tuning is introduced, the performance of our model is nevertheless largely decided by the generalization ability of the CLIP model. Another limitation of our method is that mask proposals are generated by a fixed network (once pre-trained), which might limit its capability for object types of arbitrary specification. + +Acknowledgement. This work is supported by NSF Award IIS-2127544. + +# References + +[1] Ankan Bansal, Karan Sikka, Gaurav Sharma, Rama Chellappa, and Ajay Divakaran. Zero-shot object detection. In + +Proceedings of the European Conference on Computer Vision, pages 384-400, 2018. 5, 6 +[2] David Biertimpel, Sindi Shkodrani, Anil S Baslamisli, and Nóra Baka. Prior to segment: Foreground cues for weakly annotated classes in partially supervised instance segmentation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2824-2833, 2021. 6 +[3] Maxime Bucher, Tuan-Hung Vu, Matthieu Cord, and Patrick Pérez. Zero-shot semantic segmentation. Advances in Neural Information Processing Systems, 32, 2019. 2 +[4] Han Cai, Chuang Gan, Ligeng Zhu, and Song Han. Tinytl: Reduce memory, not parameters for efficient on-device learning. Advances in Neural Information Processing Systems, 33:11285-11297, 2020. 2 +[5] Zhaowei Cai, Gukyeong Kwon, Avinash Ravichandran, Erhan Bas, Zhuowen Tu, Rahul Bhotika, and Stefano Soatto. X-detr: A versatile architecture for instance-wise vision-language tasks. arXiv preprint arXiv:2204.05626, 2022. 2 +[6] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Proceedings of the European Conference on Computer Vision, pages 213-229. Springer, 2020. 1, 2 +[7] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1290–1299, 2022. 1, 2, 5, 9 +[8] Bowen Cheng, Alex Schwing, and Alexander Kirillov. Per-pixel classification is not all you need for semantic segmentation. Advances in Neural Information Processing Systems, 34:17864-17875, 2021. 1 +[9] Zheng Ding, Jieke Wang, and Zhuowen Tu. Open-vocabulary universal image segmentation with maskclip. In International Conference on Machine Learning, 2023. 1, 2, 3, 4, 5, 6, 7, 8, 9 +[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2020. 2 +[11] Mark Everingham, SM Eslami, Luc Van Gool, Christopher KI Williams, John Winn, and Andrew Zisserman. The Pascal visual object classes challenge: A retrospective. International Journal of Computer Vision, 111(1):98-136, 2015. 5 +[12] Golnaz Ghiasi, Xiuye Gu, Yin Cui, and Tsung-Yi Lin. Scaling open-vocabulary image segmentation with image-level labels. In Proceedings of the European Conference on Computer Vision, pages 540-557. Springer, 2022. 2, 6, 8, 9 +[13] Xiuye Gu, Tsung-Yi Lin, Weicheng Kuo, and Yin Cui. Open-vocabulary object detection via vision and language knowledge distillation. In International Conference on Learning Representations, 2022. 1, 2, 5 +[14] Kaiming He, Georgia Gkioxari, Piotr Dólar, and Ross Girshick. Mask r-cnn. In Proceedings of the IEEE International + +Conference on Computer Vision, pages 2961-2969, 2017. 2, 5 +[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016. 2 +[16] Xuehai He, Chunyuan Li, Pengchuan Zhang, Jianwei Yang, and Xin Eric Wang. Parameter-efficient fine-tuning for vision transformers. arXiv preprint arXiv:2203.16329, 2022. 3 +[17] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, et al. Distilling the knowledge in a neural network. arXiv preprint arXiv:1503.02531, 2015. 2 +[18] Dat Huynh, Jason Kuen, Zhe Lin, Jiumiang Gu, and Ehsan Elhamifar. Open-vocabulary instance segmentation via robust cross-modal pseudo-labeling. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7020-7031, 2022. 2, 5, 6 +[19] Jaedong Hwang, Seoung Wug Oh, Joon-Young Lee, and Bohyung Han. Exemplar-based open-set panoptic segmentation network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1175–1184, 2021. 2 +[20] Chao Jia, Yinfei Yang, Ye Xia, Yi-Ting Chen, Zarana Parekh, Hieu Pham, Quoc Le, Yun-Hsuan Sung, Zhen Li, and Tom Duerig. Scaling up visual and vision-language representation learning with noisy text supervision. In International Conference on Machine Learning, pages 4904-4916, 2021. 2, 6 +[21] Menglin Jia, Luming Tang, Bor-Chun Chen, Claire Cardie, Serge Belongie, Bharath Hariharan, and Ser-Nam Lim. Visual prompt tuning. In Proceedings of the European Conference on Computer Vision, pages 709-727. Springer, 2022. 3 +[22] Alexander Kirillov, Kaiming He, Ross Girshick, Carsten Rother, and Piotr Dollar. Panoptic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9404-9413, 2019. 2, 5 +[23] Boyi Li, Kilian Q Weinberger, Serge Belongie, Vladlen Koltun, and René Ranftl. Language-driven semantic segmentation. In International Conference on Learning Representations, 2022. 2, 6 +[24] Liunian Harold Li, Pengchuan Zhang, Haotian Zhang, Jianwei Yang, Chunyuan Li, Yiwu Zhong, Lijuan Wang, Lu Yuan, Lei Zhang, Jenq-Neng Hwang, et al. Grounded language-image pre-training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10965-10975, 2022. 2 +[25] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In Proceedings of the European Conference on Computer Vision, pages 740-755. Springer, 2014. 3, 5 +[26] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In International Conference on Learning Representations, 2018. 5 +[27] Huaishao Luo, Lei Ji, Ming Zhong, Yang Chen, Wen Lei, Nan Duan, and Tianrui Li. Clip4clip: An empirical study + +of clip for end to end video clip retrieval. arXiv preprint arXiv:2104.08860, 2021. 2 +[28] Luke Melas-Kyriazi, Christian Rupprecht, Iro Laina, and Andrea Vedaldi. Deep spectral methods: A surprisingly strong baseline for unsupervised semantic segmentation and localization. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8364-8375, 2022. 2 +[29] Roozbeh Mottaghi, Xianjie Chen, Xiaobai Liu, Nam-Gyu Cho, Seong-Whan Lee, Sanja Fidler, Raquel Urtasun, and Alan Yuille. The role of context for object detection and semantic segmentation in the wild. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 891–898, 2014. 5 +[30] Or Patashnik, Zongze Wu, Eli Shechtman, Daniel Cohen-Or, and Dani Lischinski. Styleclip: Text-driven manipulation of stylegan imagery. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2085–2094, 2021. 2 +[31] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning, pages 8748-8763. PMLR, 2021. 1, 9 +[32] Yongming Rao, Wenliang Zhao, Guangyi Chen, Yansong Tang, Zheng Zhu, Guan Huang, Jie Zhou, and Jiwen Lu. Denseclip: Language-guided dense prediction with context-aware prompting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18082-18091, 2022. 2, 3 +[33] Sylvestre-Alvise Rebuffi, Hakan Bilen, and Andrea Vedaldi. Learning multiple visual domains with residual adapters. Advances in Neural Information Processing Systems, 30, 2017. 2 +[34] Mark Sandler, Andrey Zhmoginov, Max Vlademyrov, and Andrew Jackson. Fine-tuning image transformers using learnable memory. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12155-12164, 2022. 3 +[35] Sheng Shen, Liunian Harold Li, Hao Tan, Mohit Bansal, Anna Rohrbach, Kai-Wei Chang, Zhewei Yao, and Kurt Keutzer. How much can clip benefit vision-and-language tasks? In International Conference on Learning Representations, 2022. 2 +[36] Jamie Shotton, John Winn, Carsten Rother, and Antonio Criminisi. Textonboost: Joint appearance, shape and context modeling for multi-class object recognition and segmentation. In Proceedings of the European Conference on Computer Vision, pages 1-15. Springer, 2006. 2 +[37] Karen Simonyan and Andrew Zisserman. Very deep convolutional networks for large-scale image recognition. arXiv preprint arXiv:1409.1556, 2014. 2 +[38] Yi-Lin Sung, Jaemin Cho, and Mohit Bansal. VI-adapter: Parameter-efficient transfer learning for vision-and-language tasks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5227-5237, 2022. 3 + +[39] Zhuowen Tu. Auto-context and its application to high-level vision tasks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1-8. IEEE, 2008. 2 +[40] Zhuowen Tu, Xiangrong Chen, Alan L Yuille, and Song-Chun Zhu. Image parsing: Unifying segmentation, detection, and recognition. International Journal of Computer Vision, 63(2):113-140, 2005. 2 +[41] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in Neural Information Processing Systems, 30, 2017. 2 +[42] Weiyao Wang, Matt Feiszli, Heng Wang, Jitendra Malik, and Du Tran. Open-world instance segmentation: Exploiting pseudo ground truth from learned pairwise affinity. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4422-4432, 2022. 2 +[43] Xinlong Wang, Zhiding Yu, Shalini De Mello, Jan Kautz, Anima Anandkumar, Chunhua Shen, and Jose M Alvarez. Freesolo: Learning to segment objects without annotations. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14176-14186, 2022. 2 +[44] Zhecan Wang, Noel Codella, Yen-Chun Chen, Luowei Zhou, Jianwei Yang, Xiyang Dai, Bin Xiao, Haoxuan You, Shih-Fu Chang, and Lu Yuan. Clip-td: Clip targeted distillation for vision-language tasks. arXiv preprint arXiv:2201.05729, 2022. 2 +[45] Yuwen Xiong, Renjie Liao, Hengshuang Zhao, Rui Hu, Min Bai, Ersin Yumer, and Raquel Urtasun. Upsnet: A unified panoptic segmentation network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. 2 +[46] Mengde Xu, Zheng Zhang, Fangyun Wei, Yutong Lin, Yue Cao, Han Hu, and Xiang Bai. A simple baseline for open-vocabulary semantic segmentation with pre-trained vision-language model. In Proceedings of the European Conference on Computer Vision, pages 736-753. Springer, 2022. 2 +[47] Lihe Yang, Wei Zhuo, Lei Qi, Yinghuan Shi, and Yang Gao. St++: Make self-training work better for semi-supervised semantic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4268-4277, 2022. 2 +[48] Jianlong Yuan, Yifan Liu, Chunhua Shen, Zhibin Wang, and Hao Li. A simple baseline for semi-supervised semantic segmentation with strong data augmentation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 8229-8238, 2021. 2 +[49] Yuhang Zang, Wei Li, Kaiyang Zhou, Chen Huang, and Chen Change Loy. Open-vocabulary detr with conditional matching. In Proceedings of the European Conference on Computer Vision, pages 106-122, 2022. 2 +[50] Alireza Zareian, Kevin Dela Rosa, Derek Hao Hu, and Shih-Fu Chang. Open-vocabulary object detection using captions. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14393-14402, 2021. 2, 5, 6 + +[51] Jeffrey O Zhang, Alexander Sax, Amir Zamir, Leonidas Guibas, and Jitendra Malik. Side-tuning: a baseline for network adaptation via additive side networks. In Proceedings of the European Conference on Computer Vision, pages 698-714. Springer, 2020. 2 +[52] Linfeng Zhang, Jiebo Song, Anni Gao, Jingwei Chen, Chenglong Bao, and Kaisheng Ma. Be your own teacher: Improve the performance of convolutional neural networks via self distillation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 3713-3722, 2019. 2 +[53] Renrui Zhang, Rongyao Fang, Wei Zhang, Peng Gao, Kunchang Li, Jifeng Dai, Yu Qiao, and Hongsheng Li. Tip-adapter: Training-free clip-adapter for better vision-language modeling. arXiv preprint arXiv:2111.03930, 2021. 3 +[54] Ye Zheng, Jiahong Wu, Yongqiang Qin, Faen Zhang, and Li Cui. Zero-shot instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2593-2602, 2021. 6 +[55] Yiwu Zhong, Jianwei Yang, Pengchuan Zhang, Chunyuan Li, Noel Codella, Liunian Harold Li, Luowei Zhou, Xiyang Dai, Lu Yuan, Yin Li, and Jianfeng Gao. Regionclip: Region-based language-image pretraining. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 16793-16803, 2022. 1, 2 +[56] Bolei Zhou, Hang Zhao, Xavier Puig, Sanja Fidler, Adela Barriuso, and Antonio Torralba. Scene parsing through ade20k dataset. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 633-641, 2017. 5 +[57] Bolei Zhou, Hang Zhao, Xavier Puig, Tete Xiao, Sanja Fidler, Adela Barriuso, and Antonio Torralba. Semantic understanding of scenes through the ade20k dataset. International Journal of Computer Vision, 127(3):302-321, 2019. 5 +[58] Chong Zhou, Chen Change Loy, and Bo Dai. Extract free dense labels from clip. In Proceedings of the European Conference on Computer Vision, pages 696-712. Springer, 2022. 2 \ No newline at end of file diff --git a/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/images.zip b/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..47ded929200979d6f45a5419f3c60b0a4b2fe770 --- /dev/null +++ b/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:8350bed6138e7d85a7967018fa2f02f9d4b2cccc76ae4a063c2045388de72d4b +size 637064 diff --git a/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/layout.json b/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..e24d06b6c73262ab68944b68a4b46aad0a1d6fcd --- /dev/null +++ b/2023/MasQCLIP for Open-Vocabulary Universal Image Segmentation/layout.json @@ -0,0 +1,12666 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 97, + 103, + 498, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 97, + 103, + 498, + 121 + ], + "spans": [ + { + "bbox": [ + 97, + 103, + 498, + 121 + ], + "type": "text", + "content": "MasQCLIP for Open-Vocabulary Universal Image Segmentation" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 154, + 152, + 440, + 168 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 154, + 152, + 440, + 168 + ], + "spans": [ + { + "bbox": [ + 154, + 152, + 440, + 168 + ], + "type": "text", + "content": "Xin " + }, + { + "bbox": [ + 154, + 152, + 440, + 168 + ], + "type": "inline_equation", + "content": "\\mathrm{Xu}^{1*}" + }, + { + "bbox": [ + 154, + 152, + 440, + 168 + ], + "type": "text", + "content": ", Tianyi " + }, + { + "bbox": [ + 154, + 152, + 440, + 168 + ], + "type": "inline_equation", + "content": "\\mathrm{Xiong}^{2*}" + }, + { + "bbox": [ + 154, + 152, + 440, + 168 + ], + "type": "text", + "content": ", Zheng " + }, + { + "bbox": [ + 154, + 152, + 440, + 168 + ], + "type": "inline_equation", + "content": "\\mathrm{Ding}^3" + }, + { + "bbox": [ + 154, + 152, + 440, + 168 + ], + "type": "text", + "content": ", and Zhuowen " + }, + { + "bbox": [ + 154, + 152, + 440, + 168 + ], + "type": "inline_equation", + "content": "\\mathrm{Tu}^3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 250, + 177, + 343, + 191 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 250, + 177, + 343, + 191 + ], + "spans": [ + { + "bbox": [ + 250, + 177, + 343, + 191 + ], + "type": "text", + "content": "1Peking University" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 244, + 191, + 348, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 244, + 191, + 348, + 205 + ], + "spans": [ + { + "bbox": [ + 244, + 191, + 348, + 205 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 244, + 191, + 348, + 205 + ], + "type": "text", + "content": "Tsinghua University" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 209, + 205, + 385, + 220 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 209, + 205, + 385, + 220 + ], + "spans": [ + { + "bbox": [ + 209, + 205, + 385, + 220 + ], + "type": "text", + "content": "3University of California, San Diego" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 143, + 255, + 192, + 268 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 255, + 192, + 268 + ], + "spans": [ + { + "bbox": [ + 143, + 255, + 192, + 268 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 281, + 290, + 497 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 281, + 290, + 497 + ], + "spans": [ + { + "bbox": [ + 46, + 281, + 290, + 497 + ], + "type": "text", + "content": "We present a new method for open-vocabulary universal image segmentation, which is capable of performing instance, semantic, and panoptic segmentation under a unified framework. Our approach, called MasQCLIP, seamlessly integrates with a pre-trained CLIP model by utilizing its dense features, thereby circumventing the need for extensive parameter training. MasQCLIP emphasizes two new aspects when building an image segmentation method with a CLIP model: 1) a student-teacher module to deal with masks of the novel (unseen) classes by distilling information from the base (seen) classes; 2) a fine-tuning process to update model parameters for the queries " + }, + { + "bbox": [ + 46, + 281, + 290, + 497 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 46, + 281, + 290, + 497 + ], + "type": "text", + "content": " within the CLIP model. Thanks to these two simple and intuitive designs, MasQCLIP is able to achieve state-of-the-art performances with a substantial gain over the competing methods by a large margin across all three tasks, including open-vocabulary instance, semantic, and panoptic segmentation. Project page is at https://masqclip.github.io/." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 517, + 128, + 530 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 517, + 128, + 530 + ], + "spans": [ + { + "bbox": [ + 47, + 517, + 128, + 530 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 538, + 287, + 694 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 538, + 287, + 694 + ], + "spans": [ + { + "bbox": [ + 46, + 538, + 287, + 694 + ], + "type": "text", + "content": "By being universal and open-world, the traditional image segmentation methods that have been mainly trained in a supervised manner can be made less specific and more powerful. When an image segmentation method is open-world, it means that it can handle new concepts with novel classes or categories that are not labeled in its supervised training data. However, this is not something that can be achieved by the algorithm alone, as information about the novel classes that go beyond supervised labels cannot be generated out of thin air. Fortunately, the CLIP models [31] are trained on millions of image-text pairs, which provides a rich source of combinatorial object/scene information by mapping images and texts into the same semantic space." + } + ] + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 319, + 254, + 389, + 311 + ], + "blocks": [ + { + "bbox": [ + 319, + 254, + 389, + 311 + ], + "lines": [ + { + "bbox": [ + 319, + 254, + 389, + 311 + ], + "spans": [ + { + "bbox": [ + 319, + 254, + 389, + 311 + ], + "type": "image", + "image_path": "8a117942400126da50eea6613d51923129d0ebb32b65ada22476d0eba2c993e1.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 320, + 314, + 389, + 371 + ], + "blocks": [ + { + "bbox": [ + 320, + 314, + 389, + 371 + ], + "lines": [ + { + "bbox": [ + 320, + 314, + 389, + 371 + ], + "spans": [ + { + "bbox": [ + 320, + 314, + 389, + 371 + ], + "type": "image", + "image_path": "315e1c785e7a16abeba1a14d1455f93f6562aecdd3b37845a2c5a4ae5eccd95f.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 322, + 372, + 388, + 380 + ], + "lines": [ + { + "bbox": [ + 322, + 372, + 388, + 380 + ], + "spans": [ + { + "bbox": [ + 322, + 372, + 388, + 380 + ], + "type": "text", + "content": "Mask AP50 on COCO Split" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 392, + 255, + 460, + 311 + ], + "blocks": [ + { + "bbox": [ + 392, + 255, + 460, + 311 + ], + "lines": [ + { + "bbox": [ + 392, + 255, + 460, + 311 + ], + "spans": [ + { + "bbox": [ + 392, + 255, + 460, + 311 + ], + "type": "image", + "image_path": "2220f69fbd09bb6c62a784be26762ce5ddcd2137d3095f430200475ca9950a69.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 393, + 312, + 462, + 367 + ], + "blocks": [ + { + "bbox": [ + 393, + 312, + 462, + 367 + ], + "lines": [ + { + "bbox": [ + 393, + 312, + 462, + 367 + ], + "spans": [ + { + "bbox": [ + 393, + 312, + 462, + 367 + ], + "type": "image", + "image_path": "9346a82e2d2e27c90aadd778c0fbdd0bf7fa6c65cf6440732b1eaef6b34e05ce.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 405, + 372, + 448, + 379 + ], + "lines": [ + { + "bbox": [ + 405, + 372, + 448, + 379 + ], + "spans": [ + { + "bbox": [ + 405, + 372, + 448, + 379 + ], + "type": "text", + "content": "mIoU on ADE20k" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 462, + 255, + 529, + 310 + ], + "blocks": [ + { + "bbox": [ + 462, + 255, + 529, + 310 + ], + "lines": [ + { + "bbox": [ + 462, + 255, + 529, + 310 + ], + "spans": [ + { + "bbox": [ + 462, + 255, + 529, + 310 + ], + "type": "image", + "image_path": "36527c69802f632a96a027de3a1a417299e760ac78347d0a9d6078363c29eef4.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 463, + 312, + 523, + 366 + ], + "blocks": [ + { + "bbox": [ + 463, + 312, + 523, + 366 + ], + "lines": [ + { + "bbox": [ + 463, + 312, + 523, + 366 + ], + "spans": [ + { + "bbox": [ + 463, + 312, + 523, + 366 + ], + "type": "image", + "image_path": "3dd716ce9f3e6670a7c0682d0bec0fe23724404cd3c9a2fe1ad6a78b7bab5ddc.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 474, + 372, + 512, + 379 + ], + "lines": [ + { + "bbox": [ + 474, + 372, + 512, + 379 + ], + "spans": [ + { + "bbox": [ + 474, + 372, + 512, + 379 + ], + "type": "text", + "content": "PQ on ADE20k" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 354, + 392, + 389, + 400 + ], + "blocks": [ + { + "bbox": [ + 354, + 392, + 389, + 400 + ], + "lines": [ + { + "bbox": [ + 354, + 392, + 389, + 400 + ], + "spans": [ + { + "bbox": [ + 354, + 392, + 389, + 400 + ], + "type": "image", + "image_path": "95273bac1d60a4d9164d3f13a2bc6a5fb7c2a72a2211bac682038faabda24a05.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 407, + 547, + 452 + ], + "lines": [ + { + "bbox": [ + 305, + 407, + 547, + 452 + ], + "spans": [ + { + "bbox": [ + 305, + 407, + 547, + 452 + ], + "type": "text", + "content": "Figure 1: We present the visualization and quantitative results of MasQCLIP on open-vocabulary segmentation with a universal model architecture. As shown, we achieve state-of-the-art performances across three segmentation tasks." + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_caption" + } + ], + "index": 20 + }, + { + "type": "image", + "bbox": [ + 457, + 392, + 468, + 400 + ], + "blocks": [ + { + "bbox": [ + 401, + 383, + 455, + 400 + ], + "lines": [ + { + "bbox": [ + 401, + 383, + 455, + 400 + ], + "spans": [ + { + "bbox": [ + 401, + 383, + 455, + 400 + ], + "type": "text", + "content": "Model Architecture MaskCLIP Ope" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 457, + 392, + 468, + 400 + ], + "lines": [ + { + "bbox": [ + 457, + 392, + 468, + 400 + ], + "spans": [ + { + "bbox": [ + 457, + 392, + 468, + 400 + ], + "type": "image", + "image_path": "e51e0a63327320e81b59e65038a6449476ec62250b223e106b0cd29bdd29ba15.jpg" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 470, + 392, + 498, + 400 + ], + "lines": [ + { + "bbox": [ + 470, + 392, + 498, + 400 + ], + "spans": [ + { + "bbox": [ + 470, + 392, + 498, + 400 + ], + "type": "text", + "content": "XPM" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_caption" + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 472, + 545, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 472, + 545, + 567 + ], + "spans": [ + { + "bbox": [ + 304, + 472, + 545, + 567 + ], + "type": "text", + "content": "As CLIP models are trained contrastively at the global image-text level, they do not directly output segmentation maps at the pixel or region level. Recent works [9, 13, 55] demonstrate the feasibility of adopting and locking a pretrained CLIP model for open-vocabulary image segmentation by adopting a two-stage approach, which first generates class-agnostic mask proposals and subsequently classifies each mask region based on a CLIP model." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "type": "text", + "content": "This decoupled two-stage design, involving localization and then classification, is considered advantageous for open-vocabulary universal segmentation. First, it does not depend on any task specificity. Recent works [7, 8] have attempted to unify instance, semantic, and panoptic segmentation through Transformer-based architectures [6], and the CLIP-based region classification module itself is directly applicable to different types of masks (instance/semantic). Second, it is a natural choice to utilize CLIP models exclusively for object/scene classification rather than localization. The reason is that the dense features within a CLIP visual encoder only carry semantic information, but can-" + } + ] + } + ], + "index": 26 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 702, + 128, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 128, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 128, + 712 + ], + "type": "text", + "content": "*Equal Contribution." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 297, + 748, + 313, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 748, + 313, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 748, + 313, + 757 + ], + "type": "text", + "content": "887" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "type": "text", + "content": "not discriminate between different objects belonging to the same category." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 96, + 287, + 263 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 96, + 287, + 263 + ], + "spans": [ + { + "bbox": [ + 46, + 96, + 287, + 263 + ], + "type": "text", + "content": "However, recent works [9, 20] still exhibit limitations with regard to being open-world. Specifically, the class-agnostic mask proposal network is trained only on the supervision of a limited set of base classes, which restricts its ability to generate mask proposals beyond supervision. Hence, the model performance is hindered when dealing with novel or unseen categories. In addition, although previous works have attempted to introduce some additional modules for mask classification, they fail to fully bridge the gap between image-level and region-level representation, thus lacking in adaptation to mask classification. The balance between maintaining generalization for more categories and adapting CLIP models for mask classification tasks needs further exploration." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 263, + 288, + 455 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 263, + 288, + 455 + ], + "spans": [ + { + "bbox": [ + 46, + 263, + 288, + 455 + ], + "type": "text", + "content": "In this paper, we aim to conquer these weaknesses. We introduce a new approach called MasQCLIP that can perform open-vocabulary instance, semantic, and panoptic segmentation under a single framework. To accomplish this, MasQCLIP uses a similar two-stage model design: 1) a mask generator stage that extracts object/scene masks, and 2) an encoder-only module that performs mask classification. We are also inspired by the Mask Class Token strategy from MaskCLIP [9], which is tightly integrated with a given CLIP model. MasQCLIP is different from MaskCLIP [9] in two key areas: 1) the use of a student-teacher self-training module that significantly enhances the generation of novel class masks, and 2) fine-tuning the query parameters in the CLIP visual encoder, which better adapts the CLIP models for mask region representations. The following are the contributions of our work:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 58, + 460, + 287, + 656 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 58, + 460, + 287, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 460, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 58, + 460, + 287, + 533 + ], + "type": "text", + "content": "- We develop MasQCLIP for open-vocabulary universal image segmentation that demonstrates substantial performance improvement over the current state-of-the-art methods by a large margin across all three tasks including open-vocabulary instance, semantic, and panoptic segmentation." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 58, + 533, + 287, + 582 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 533, + 287, + 582 + ], + "spans": [ + { + "bbox": [ + 58, + 533, + 287, + 582 + ], + "type": "text", + "content": "- We design a progressive distillation process to generate more novel mask proposals beyond supervision, thus taking a step forward toward open-world mask generation." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 58, + 583, + 287, + 656 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 583, + 287, + 656 + ], + "spans": [ + { + "bbox": [ + 58, + 583, + 287, + 656 + ], + "type": "text", + "content": "- We propose a parameter-efficient fine-tuning strategy, MasQ-Tuning, which only tunes the query parameters. When coupled with Mask Class Tokens, MasQ-Tuning is able to preserve the generalization of a pre-trained image-level CLIP model while greatly enhancing its adaptation for segmentation tasks." + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 47, + 669, + 134, + 681 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 669, + 134, + 681 + ], + "spans": [ + { + "bbox": [ + 47, + 669, + 134, + 681 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "text", + "content": "Being universal Traditional image segmentation methods can be roughly divided into three groups: 1) instance seg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "text", + "content": "mentation [14], 2) semantic segmentation [36, 39], and 3) panoptic segmentation [22, 40]. Panoptic segmentation essentially integrates instance and semantic segmentation, but a careful algorithm design is needed [22, 45] to achieve the goal, as instance segmentation is object-centered whereas semantic segmentation is per-pixel based. The introduction and adaptation of Transformers [41] to the object detection task, Detection Transformers [6], also makes the unification of instance and semantic segmentation feasible. In particular, the Mask2Former method [7] unifies background stuff and foreground things under the query token representation by designing a Transformer-based architecture for closed-set universal image segmentation." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 236, + 545, + 333 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 236, + 545, + 333 + ], + "spans": [ + { + "bbox": [ + 304, + 236, + 545, + 333 + ], + "type": "text", + "content": "Being open-world Since it is a relatively new topic, there lacks a commonly accepted definition for being \"open-world\". There exists different terms such as zero-shot [3], open-set [19], and open-vocabulary [50]. It is gradually accepted that the open-vocabulary setting has the best alignment with the general open-world expectation where the target of interest to be extracted can be freely specified using a natural language description during inference." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 339, + 545, + 494 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 339, + 545, + 494 + ], + "spans": [ + { + "bbox": [ + 304, + 339, + 545, + 494 + ], + "type": "text", + "content": "Open-Vocabulary Detection and Segmentation Various open-vocabulary vision algorithms have been developed. A rough summary for the comparison of existing methods can be seen in [9]. Broadly speaking, there exist methods for open-vocabulary object detection [5, 13, 24, 49, 50], instance segmentation [13, 18], semantic segmentation [12, 23, 46, 58], and panoptic segmentation [9]. Previous works [27, 30, 35, 44, 49, 55] mainly focus on knowledge distillation from an existing CLIP model, but our method integrates CLIP models rather than performing distillation from CLIP models. Some recent works [32, 58] have also attempted to extract dense features from CLIP models to represent pixelwise features." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 502, + 545, + 622 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 502, + 545, + 622 + ], + "spans": [ + { + "bbox": [ + 304, + 502, + 545, + 622 + ], + "type": "text", + "content": "Knowledge Distillation Knowledge Distillation [17] has been proposed to extract knowledge from the teacher model to the student model. It is called self-distillation [52] when both teacher and student models adopt the same model architecture. For the image segmentation task, self-training with pseudo labels has been proposed to improve the quality of predicted masks in self-supervised learning [28, 43] and semi-supervised learning [42, 47, 48]. We use a similar strategy but focus on self-distilling novel mask proposals from the teacher model." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 629, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 545, + 715 + ], + "type": "text", + "content": "Fine-tuning Fine-tuning aims to efficiently utilize knowledge from large models for downstream tasks. In terms of ConvNet [15, 37], many fine-tuning strategies have been proposed, including bias tuning [4], side tuning [51], and residual adapter [33]. After Transformer [41] is introduced into the field of computer vision, several fine-tuning methods have been proposed for ViT [10]. Recent works have" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "text", + "content": "888" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 75, + 74, + 518, + 230 + ], + "blocks": [ + { + "bbox": [ + 75, + 74, + 518, + 230 + ], + "lines": [ + { + "bbox": [ + 75, + 74, + 518, + 230 + ], + "spans": [ + { + "bbox": [ + 75, + 74, + 518, + 230 + ], + "type": "image", + "image_path": "286be5ea722844ac01a391d1554ced57959d95b3c34a691e1d2f2d426a5c0e78.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 236, + 545, + 293 + ], + "lines": [ + { + "bbox": [ + 46, + 236, + 545, + 293 + ], + "spans": [ + { + "bbox": [ + 46, + 236, + 545, + 293 + ], + "type": "text", + "content": "Figure 2: Overview of MasQCLIP. MasQCLIP consists of a class-agnostic mask proposal network and a mask classification module based on CLIP. In the mask proposal network, we apply progressive distillation to segment masks beyond base classes. Please refer to Fig. 3 for more details. After we obtain an open-world mask proposal network, the predicted masks are then sent to the classification module to obtain labels. To efficiently utilize the dense CLIP features, we propose MasQ-Tuning. We set new query projections " + }, + { + "bbox": [ + 46, + 236, + 545, + 293 + ], + "type": "inline_equation", + "content": "f_{Q}^{\\prime}" + }, + { + "bbox": [ + 46, + 236, + 545, + 293 + ], + "type": "text", + "content": " for the Mask Class Tokens to obtain optimal attention weights, and " + }, + { + "bbox": [ + 46, + 236, + 545, + 293 + ], + "type": "inline_equation", + "content": "f_{Q}^{\\prime}" + }, + { + "bbox": [ + 46, + 236, + 545, + 293 + ], + "type": "text", + "content": " at each layer are the only learnable parameters." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 306, + 289, + 403 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 306, + 289, + 403 + ], + "spans": [ + { + "bbox": [ + 46, + 306, + 289, + 403 + ], + "type": "text", + "content": "explored subspace training [16] for low-dimensional reparameterization and prompt tuning [21, 34] for adaptation. In terms of CLIP models, [38, 53] insert adapters into pretrained CLIP models, and DenseCLIP [32] uses CLIP parameters as initialization for segmentation tasks. However, existing works mainly make use of the pre-trained models for a specific dataset, and they do not fully exploit the intrinsic generalization ability in pre-trained models." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 428, + 125, + 441 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 428, + 125, + 441 + ], + "spans": [ + { + "bbox": [ + 47, + 428, + 125, + 441 + ], + "type": "text", + "content": "3. Preliminary" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 453, + 287, + 585 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 453, + 287, + 585 + ], + "spans": [ + { + "bbox": [ + 46, + 453, + 287, + 585 + ], + "type": "text", + "content": "MaskCLIP [9] adapts the CLIP model for segmentation tasks through a two-stage pipeline. Specifically, a class-agnostic mask proposal network first generates candidate masks, then MaskCLIP utilizes dense CLIP features to classify each mask proposal with a corresponding Mask Class Token. Mask Class Tokens are initialized with the class token in the CLIP visual encoder, then are appended alongside the original CLIP tokens (image tokens and a class token). Mask Class Tokens extract features from CLIP tokens through the masked cross-attention mechanism where mask proposals also serve as attention masks, i.e.," + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 52, + 603, + 286, + 617 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 603, + 286, + 617 + ], + "spans": [ + { + "bbox": [ + 52, + 603, + 286, + 617 + ], + "type": "interline_equation", + "content": "\\operatorname {C r o s s A t t n} (\\cdot) = \\operatorname {s o f t m a x} \\left(Q _ {\\text {m a s k}} K _ {\\text {i m g}} ^ {T} + \\mathcal {M} _ {\\text {m a s k}}\\right) \\cdot V _ {\\text {i m g}}, \\tag {1}", + "image_path": "7054d1766bc6967818f6656aafbff20e12b83a00fdfee3b840096299fdfbb725.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 58, + 620, + 287, + 634 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 620, + 287, + 634 + ], + "spans": [ + { + "bbox": [ + 58, + 620, + 287, + 634 + ], + "type": "interline_equation", + "content": "Q _ {\\text {m a s k}}, K _ {\\text {i m g}}, V _ {\\text {i m g}} = f _ {Q} \\left(x _ {\\text {m a s k}}\\right), f _ {K} \\left(x _ {\\text {i m g}}\\right), f _ {V} \\left(x _ {\\text {i m g}}\\right). \\tag {2}", + "image_path": "0dab675cd6a5debd9b9441306f93c059adf069cfdc65bc1b157117d39118d357.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "text", + "content": "Here, " + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "inline_equation", + "content": "x_{\\mathrm{mask}} \\in \\mathbb{R}^{m \\times C}" + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "inline_equation", + "content": "x_{\\mathrm{img}} \\in \\mathbb{R}^{p \\times C}" + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "text", + "content": " denote " + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "text", + "content": " Mask Class Tokens and " + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "text", + "content": " CLIP tokens respectively, and " + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "inline_equation", + "content": "f_{Q}, f_{K}, f_{V}" + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "text", + "content": " denote the projections for query, key, and value respectively. In MaskCLIP, " + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "inline_equation", + "content": "f_{Q}, f_{K}, f_{V}" + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "text", + "content": " are frozen to maintain generalization. The attention mask " + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_{\\mathrm{mask}} \\in \\mathbb{R}^{m \\times p}" + }, + { + "bbox": [ + 46, + 652, + 287, + 713 + ], + "type": "text", + "content": " is derived as" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 313, + 331, + 545, + 373 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 313, + 331, + 545, + 373 + ], + "spans": [ + { + "bbox": [ + 313, + 331, + 545, + 373 + ], + "type": "interline_equation", + "content": "\\mathcal {M} _ {\\text {m a s k}} (i, j) = \\left\\{ \\begin{array}{l l} 0 & \\text {i f i - t h m a s k f a l l s i n j - t h p a t c h} \\\\ - \\infty & \\text {o t h e r w i s e} \\end{array} . \\right. \\tag {3}", + "image_path": "f0a58bb2f09e29a8881aa77547f501b7c2d9bb5f4380d34c3a73cd353e1c122f.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 376, + 545, + 412 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 376, + 545, + 412 + ], + "spans": [ + { + "bbox": [ + 305, + 376, + 545, + 412 + ], + "type": "text", + "content": "The final classification scores are the dot product between Mask Class Tokens and the language descriptors from the CLIP language encoder." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 432, + 366, + 444 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 432, + 366, + 444 + ], + "spans": [ + { + "bbox": [ + 306, + 432, + 366, + 444 + ], + "type": "text", + "content": "4. Methods" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 455, + 405, + 468 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 455, + 405, + 468 + ], + "spans": [ + { + "bbox": [ + 306, + 455, + 405, + 468 + ], + "type": "text", + "content": "4.1. Problem Setting" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "spans": [ + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "text", + "content": "During training, the model is only provided with a set of images and their annotations on base classes " + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "inline_equation", + "content": "C_B" + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "text", + "content": ". We denote the training dataset as " + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_B = \\{(I_i, \\mathcal{Y}_i)\\}_{i=1}^N" + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "text", + "content": ". Each annotation " + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}_i" + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "text", + "content": " contains ground-truth masks " + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}_i^M" + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "text", + "content": " and their labels " + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}_i^L" + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "text", + "content": " on base classes in image " + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "inline_equation", + "content": "I_i" + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "text", + "content": ". In the inference stage, we evaluate our model on another set of images with a new set of novel classes " + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "inline_equation", + "content": "C_N" + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "text", + "content": ", and the testing dataset is denoted as " + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_N" + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "text", + "content": ". According to the relationship between " + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_B" + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_N" + }, + { + "bbox": [ + 304, + 476, + 545, + 585 + ], + "type": "text", + "content": ", previous works mainly use two settings:" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 317, + 601, + 545, + 672 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 317, + 601, + 545, + 625 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 601, + 545, + 625 + ], + "spans": [ + { + "bbox": [ + 317, + 601, + 545, + 625 + ], + "type": "text", + "content": "- Cross-dataset. " + }, + { + "bbox": [ + 317, + 601, + 545, + 625 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_B" + }, + { + "bbox": [ + 317, + 601, + 545, + 625 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 317, + 601, + 545, + 625 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_N" + }, + { + "bbox": [ + 317, + 601, + 545, + 625 + ], + "type": "text", + "content": " are different datasets, and class sets " + }, + { + "bbox": [ + 317, + 601, + 545, + 625 + ], + "type": "inline_equation", + "content": "C_B" + }, + { + "bbox": [ + 317, + 601, + 545, + 625 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 317, + 601, + 545, + 625 + ], + "type": "inline_equation", + "content": "C_N" + }, + { + "bbox": [ + 317, + 601, + 545, + 625 + ], + "type": "text", + "content": " may overlap." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 317, + 635, + 545, + 672 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 635, + 545, + 672 + ], + "spans": [ + { + "bbox": [ + 317, + 635, + 545, + 672 + ], + "type": "text", + "content": "- Base-novel. " + }, + { + "bbox": [ + 317, + 635, + 545, + 672 + ], + "type": "inline_equation", + "content": "C_B" + }, + { + "bbox": [ + 317, + 635, + 545, + 672 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 317, + 635, + 545, + 672 + ], + "type": "inline_equation", + "content": "C_N" + }, + { + "bbox": [ + 317, + 635, + 545, + 672 + ], + "type": "text", + "content": " are disjoint, i.e., " + }, + { + "bbox": [ + 317, + 635, + 545, + 672 + ], + "type": "inline_equation", + "content": "C_B \\cap C_N = \\varnothing" + }, + { + "bbox": [ + 317, + 635, + 545, + 672 + ], + "type": "text", + "content": ". Under this setting, the same dataset, such as COCO [25], is used during training and testing." + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": "In our paper, we evaluate our proposed algorithm on both of the above settings." + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "text", + "content": "889" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 66, + 70, + 267, + 178 + ], + "blocks": [ + { + "bbox": [ + 66, + 70, + 267, + 178 + ], + "lines": [ + { + "bbox": [ + 66, + 70, + 267, + 178 + ], + "spans": [ + { + "bbox": [ + 66, + 70, + 267, + 178 + ], + "type": "image", + "image_path": "e49f49ec6be19ff7cf4257afd6fc71beabf1f2a0feeb73371f184289ae8c6f5d.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 182, + 287, + 237 + ], + "lines": [ + { + "bbox": [ + 47, + 182, + 287, + 237 + ], + "spans": [ + { + "bbox": [ + 47, + 182, + 287, + 237 + ], + "type": "text", + "content": "Figure 3: Detailed interpretation of progressive distillation. We select high-quality mask proposals with novel concepts from the inference results of the teacher model as extra annotations. These extra annotations are then distilled into the student model to encourage generalization. This process is performed iteratively." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 252, + 153, + 265 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 252, + 153, + 265 + ], + "spans": [ + { + "bbox": [ + 47, + 252, + 153, + 265 + ], + "type": "text", + "content": "4.2. Proposed Method" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 272, + 271, + 284 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 272, + 271, + 284 + ], + "spans": [ + { + "bbox": [ + 47, + 272, + 271, + 284 + ], + "type": "text", + "content": "4.2.1 Progressive Distillation for Mask Generation" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "spans": [ + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "type": "text", + "content": "Object Score. In experiments, we observe that MaskCLIP [9] does not consistently assign higher confidence to mask proposals that align more accurately with ground-truth masks. Therefore, we incorporate a binary classification head to the class-agnostic mask proposal network in our MasQCLIP. The resulting object score, denoted as " + }, + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "type": "inline_equation", + "content": "p_{\\mathrm{obj}} \\in \\mathbb{R}" + }, + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "type": "text", + "content": ", estimates the quality of mask proposals. During inference, the final classification score for the " + }, + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "type": "text", + "content": "-th class is determined by " + }, + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "type": "inline_equation", + "content": "p_{\\mathrm{cls}}^{(i)} = p_{\\mathrm{obj}} \\cdot p_{\\mathrm{clip}}^{(i)}" + }, + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "type": "text", + "content": ". Here, " + }, + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "type": "inline_equation", + "content": "p_{\\mathrm{clip}}^{(i)}" + }, + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "type": "text", + "content": " represents the score for the " + }, + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 293, + 287, + 425 + ], + "type": "text", + "content": "-th class obtained from the mask classification module, which will be further discussed in Sec. 4.2.2." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "spans": [ + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "text", + "content": "If training is conducted with annotations from both base classes " + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "inline_equation", + "content": "C_B" + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "text", + "content": " and novel classes " + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "inline_equation", + "content": "C_N" + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "text", + "content": ", the object score can serve as a general indicator of mask quality. However, when supervision is only provided on " + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "inline_equation", + "content": "C_B" + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "text", + "content": ", the object score is more reflective of the quality of base masks, leading to bias toward " + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "inline_equation", + "content": "C_B" + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "text", + "content": ". But we will show in Sec. 5.4.1 that incorporating object scores still boosts performance on both " + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "inline_equation", + "content": "C_B" + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "inline_equation", + "content": "C_N" + }, + { + "bbox": [ + 46, + 427, + 287, + 535 + ], + "type": "text", + "content": " by a clear margin. Hence, it is still reasonable and effective to incorporate object scores for all mask proposals." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 544, + 287, + 652 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 544, + 287, + 652 + ], + "spans": [ + { + "bbox": [ + 46, + 544, + 287, + 652 + ], + "type": "text", + "content": "Progressive Distillation. To develop an open-world mask proposal network capable of generating masks beyond base classes " + }, + { + "bbox": [ + 46, + 544, + 287, + 652 + ], + "type": "inline_equation", + "content": "C_B" + }, + { + "bbox": [ + 46, + 544, + 287, + 652 + ], + "type": "text", + "content": ", we propose a progressive distillation strategy. By utilizing the object score as an indicator of mask quality, we can filter high-quality mask proposals that do not overlap with mask annotations of " + }, + { + "bbox": [ + 46, + 544, + 287, + 652 + ], + "type": "inline_equation", + "content": "C_B" + }, + { + "bbox": [ + 46, + 544, + 287, + 652 + ], + "type": "text", + "content": ", thus producing extra annotations for training. By iteratively repeating this distillation process, the network will be able to segment more concepts progressively and eventually be open-world." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "type": "text", + "content": "Specifically, we initialize the teacher model " + }, + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_{\\mu}" + }, + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "type": "text", + "content": " with the mask proposal network trained on the base annotations " + }, + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_B^{\\prime} = \\{(I_i,\\mathcal{Y}_i^M)\\}_{i = 1}^N" + }, + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "type": "text", + "content": " without class labels. To produce extra supervision for the student model " + }, + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_{\\theta}" + }, + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "type": "text", + "content": " on image " + }, + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "type": "inline_equation", + "content": "I_{i}" + }, + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "type": "text", + "content": ", we first obtain inference result " + }, + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_{\\mu}(I_i)" + }, + { + "bbox": [ + 47, + 653, + 287, + 715 + ], + "type": "text", + "content": " from the teacher model." + } + ] + } + ], + "index": 7 + }, + { + "type": "code", + "bbox": [ + 306, + 72, + 545, + 277 + ], + "blocks": [ + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "lines": [ + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": "Algorithm 1 Progressive Distillation \nRequire: Initial teacher model " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_{\\mu}" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " with parameter " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\mu" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " \nRequire: Dataset " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_B' = \\{(I_i, \\mathcal{Y}_i^M)\\}_{i=1}^N" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " (only masks) \nRequire: Score threshold " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": ", IoU threshold " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " \nfor " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " iterations do \n" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\theta \\gets \\mu" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " ▷ Initialize the student model " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_{\\theta}" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " \nfor " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "(I_i, \\mathcal{Y}_i^M)" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " in " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_B'" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " do \n" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\mathcal{Y} \\gets \\mathcal{Y}_i^M" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " ▷ " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": ": supervision for " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_{\\theta}" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\hat{\\mathcal{Y}} = \\mathcal{T}_{\\mu}(I_i)" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " \nfor " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\hat{y}" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " in " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\hat{\\mathcal{Y}}" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " do \nif " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\forall y \\in \\mathcal{Y}, IoU(\\hat{y}, y) < \\beta" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " then \nif score(" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\hat{y}" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": ") > " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " then \n" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\mathcal{Y} \\gets \\mathcal{Y} \\cup \\{\\hat{y}\\}" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "L_{\\theta} = \\mathcal{L}(\\mathcal{T}_{\\theta}(I_i), \\mathcal{Y})" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\theta \\gets \\theta - \\gamma \\nabla_{\\theta}(L_{\\theta})" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\mu \\gets \\theta" + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "text", + "content": " ▷ Update the teacher model " + }, + { + "bbox": [ + 306, + 72, + 545, + 277 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_{\\mu}" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "code_body" + } + ], + "index": 8, + "sub_type": "algorithm" + }, + { + "bbox": [ + 304, + 306, + 545, + 414 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 306, + 545, + 414 + ], + "spans": [ + { + "bbox": [ + 304, + 306, + 545, + 414 + ], + "type": "text", + "content": "Then we select mask proposals with high object scores that are non-overlap with ground-truth masks in " + }, + { + "bbox": [ + 304, + 306, + 545, + 414 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}_i^M" + }, + { + "bbox": [ + 304, + 306, + 545, + 414 + ], + "type": "text", + "content": ". These selected masks are considered novel masks and combined with " + }, + { + "bbox": [ + 304, + 306, + 545, + 414 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}_i^M" + }, + { + "bbox": [ + 304, + 306, + 545, + 414 + ], + "type": "text", + "content": " to form the supervision " + }, + { + "bbox": [ + 304, + 306, + 545, + 414 + ], + "type": "inline_equation", + "content": "\\mathcal{V}" + }, + { + "bbox": [ + 304, + 306, + 545, + 414 + ], + "type": "text", + "content": " for the student model. To further boost generalization, we train the student model progressively by updating the parameters of the student model to the teacher model iteratively. A more detailed algorithm is presented in Alg. 1. Experiments show that our algorithm works surprisingly well." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 438, + 399, + 450 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 438, + 399, + 450 + ], + "spans": [ + { + "bbox": [ + 306, + 438, + 399, + 450 + ], + "type": "text", + "content": "4.2.2 MasQ-Tuning" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "spans": [ + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "text", + "content": "Given masks produced by the class-agnostic mask proposal network, we expect to classify each mask region using pretrained CLIP models. To maintain the generalization ability of CLIP models, MaskCLIP [9] freezes all CLIP parameters and appends auxiliary tokens for region classification. According to Eq. (1), for each Mask Class Token " + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "inline_equation", + "content": "x_{\\mathrm{mask}}^{(i)} \\in \\mathbb{R}^C" + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "text", + "content": ", we have its query embedding " + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "inline_equation", + "content": "q_i = f_Q(x_{\\mathrm{mask}}^{(i)})" + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "text", + "content": " and attention weight over " + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "text", + "content": " CLIP tokens, " + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "inline_equation", + "content": "\\text{softmax}(q_i K_{\\mathrm{img}}^T + \\mathcal{M}_i) \\in \\mathbb{R}^p" + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "text", + "content": ". The attention weight indicates " + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "inline_equation", + "content": "x_{\\mathrm{mask}}^{(i)}" + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "text", + "content": " where to focus, and " + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{img}}" + }, + { + "bbox": [ + 304, + 463, + 545, + 602 + ], + "type": "text", + "content": " is interpreted as the dense CLIP features that all Mask Class Tokens can extract." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "content": "MaskCLIP preserves the original feature space of CLIP by freezing all parameters, however, it lacks in adaption. Although the appended Mask Class Tokens perform classification similar to the class token in CLIP, there is still a shift between them. Specifically, each Mask Class Token is intended to classify a mask region in an image, while the original class token is designed to extract image-level feature. To enhance adaptation ability, we propose applying new query projections " + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "inline_equation", + "content": "f_{Q}^{\\prime}" + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "content": " to each cross-attention layer for" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "text", + "content": "890" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 147, + 83 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 147, + 83 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 147, + 83 + ], + "type": "text", + "content": "Mask Class Tokens, i.e.," + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 52, + 91, + 286, + 106 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 91, + 286, + 106 + ], + "spans": [ + { + "bbox": [ + 52, + 91, + 286, + 106 + ], + "type": "interline_equation", + "content": "\\operatorname {C r o s s A t t n} (\\cdot) = \\operatorname {s o f t m a x} \\left(\\mathbf {Q} _ {\\text {m a s k}} ^ {\\prime} K _ {\\text {i m g}} ^ {T} + \\mathcal {M} _ {\\text {m a s k}}\\right) \\cdot V _ {\\text {i m g}}, \\tag {4}", + "image_path": "b39105a0dd2146626692c37453f51a0f59b0e98505182d76cffc78bdc360a10d.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 59, + 109, + 286, + 122 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 109, + 286, + 122 + ], + "spans": [ + { + "bbox": [ + 59, + 109, + 286, + 122 + ], + "type": "interline_equation", + "content": "\\mathbf {Q} _ {\\text {m a s k}} ^ {\\prime}, K _ {\\text {i m g}}, V _ {\\text {i m g}} = \\mathbf {f} _ {\\mathbf {Q}} ^ {\\prime} \\left(x _ {\\text {m a s k}}\\right), f _ {K} \\left(x _ {\\text {i m g}}\\right), f _ {V} \\left(x _ {\\text {i m g}}\\right). \\tag {5}", + "image_path": "a6074496f6d20ecd1b86d8503ce555e2e650764f8eee3c547f7a8af48e770309.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 130, + 286, + 213 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 130, + 286, + 213 + ], + "spans": [ + { + "bbox": [ + 47, + 130, + 286, + 213 + ], + "type": "text", + "content": "In this way, Mask Class Tokens obtain better attention weights through learning. In addition, since the softmax operator in Eq. (4) serves as a normalizer, the results of Eq. (4) still lie in the sub-space spanned by rows of " + }, + { + "bbox": [ + 47, + 130, + 286, + 213 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{img}}" + }, + { + "bbox": [ + 47, + 130, + 286, + 213 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 47, + 130, + 286, + 213 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{img}}" + }, + { + "bbox": [ + 47, + 130, + 286, + 213 + ], + "type": "text", + "content": " is projected from CLIP tokens and thus preserves the knowledge of CLIP. Therefore, MasQ-Tuning is able to improve adaptation while maintaining generalization." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 214, + 286, + 250 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 214, + 286, + 250 + ], + "spans": [ + { + "bbox": [ + 47, + 214, + 286, + 250 + ], + "type": "text", + "content": "To effectively inherit the knowledge and the statistics of CLIP, other layers (layernorm, FFN, and the final projection) are frozen during fine-tuning." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 252, + 286, + 300 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 252, + 286, + 300 + ], + "spans": [ + { + "bbox": [ + 47, + 252, + 286, + 300 + ], + "type": "text", + "content": "Losses. Our goal is to match the appended Mask Class Tokens with their corresponding ground-truth labels, so we use the dot-product between Mask Class Tokens and language descriptors as scores and compute cross-entropy loss, i.e.," + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 104, + 308, + 286, + 335 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 104, + 308, + 286, + 335 + ], + "spans": [ + { + "bbox": [ + 104, + 308, + 286, + 335 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {c l s}} = - \\log \\left(\\frac {\\exp \\left(s _ {y}\\right)}{\\sum_ {i} \\exp \\left(s _ {i}\\right)}\\right). \\tag {6}", + "image_path": "ecbd80c93d54fd339761e8c671915aabd22a0b06789b34934546d285bcbe9258.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 341, + 286, + 400 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 341, + 286, + 400 + ], + "spans": [ + { + "bbox": [ + 47, + 341, + 286, + 400 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 341, + 286, + 400 + ], + "type": "inline_equation", + "content": "s_i" + }, + { + "bbox": [ + 47, + 341, + 286, + 400 + ], + "type": "text", + "content": " denotes the score for " + }, + { + "bbox": [ + 47, + 341, + 286, + 400 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 47, + 341, + 286, + 400 + ], + "type": "text", + "content": "-th class and " + }, + { + "bbox": [ + 47, + 341, + 286, + 400 + ], + "type": "inline_equation", + "content": "y" + }, + { + "bbox": [ + 47, + 341, + 286, + 400 + ], + "type": "text", + "content": " is the assigned label for the mask. If a predicted mask is matched to a ground-truth mask according to an IoU threshold, we then assign the mask a label. Otherwise, we use a fixed word, \"background\", as the label for the predicted mask." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 411, + 127, + 424 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 411, + 127, + 424 + ], + "spans": [ + { + "bbox": [ + 47, + 411, + 127, + 424 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 431, + 286, + 538 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 431, + 286, + 538 + ], + "spans": [ + { + "bbox": [ + 47, + 431, + 286, + 538 + ], + "type": "text", + "content": "We evaluate MasQCLIP on three segmentation tasks to demonstrate its effectiveness and universality, and we follow the commonly-used settings in different segmentation tasks. For instance segmentation, we use base-novel setting following [18]. For semantic and panoptic segmentation, we use cross-dataset setting following [9, 13]. We show MasQCLIP achieves state-of-the-art results on all benchmarks with a universal architecture. We also conduct ablation studies to verify our proposed method." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 548, + 222, + 560 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 548, + 222, + 560 + ], + "spans": [ + { + "bbox": [ + 47, + 548, + 222, + 560 + ], + "type": "text", + "content": "5.1. Datasets and Evaluation Metrics" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 567, + 286, + 674 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 567, + 286, + 674 + ], + "spans": [ + { + "bbox": [ + 47, + 567, + 286, + 674 + ], + "type": "text", + "content": "COCO. In base-novel setting, we use instance segmentation annotations of COCO [25]. Following [18], we partition COCO annotations into 48 base classes for training and 17 novel classes for evaluation. There are 108k training images and 5k validation images. In cross-dataset setting, we use panoptic segmentation [22] annotations of COCO for training, which include 80 thing classes (foreground) and 53 stuff classes (background). There are 118k training images and 5k validation images." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 677, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 286, + 713 + ], + "type": "text", + "content": "ADE20k. ADE20k [56, 57] serves for semantic segmentation and panoptic segmentation evaluation under cross-dataset setting. There are 2k validation images in total. The" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 72, + 544, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 544, + 95 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 544, + 95 + ], + "type": "text", + "content": "full version (A-847) includes 847 classes and the short version (A-150) includes 150 classes." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 99, + 545, + 158 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 99, + 545, + 158 + ], + "spans": [ + { + "bbox": [ + 305, + 99, + 545, + 158 + ], + "type": "text", + "content": "PASCAL-Context. Pascal-Context [29] serves for semantic segmentation evaluation under cross-dataset setting. There are 5k validation images in total. The full version (P-459) includes 459 classes and the short version (P-59) includes 59 classes." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 162, + 545, + 234 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 162, + 545, + 234 + ], + "spans": [ + { + "bbox": [ + 305, + 162, + 545, + 234 + ], + "type": "text", + "content": "Evaluation Metrics. For instance segmentation, we report " + }, + { + "bbox": [ + 305, + 162, + 545, + 234 + ], + "type": "inline_equation", + "content": "mAP" + }, + { + "bbox": [ + 305, + 162, + 545, + 234 + ], + "type": "text", + "content": " (mean average precision) [25] at IoU (intersection-over-union) of 0.5 following base-novel setting [1, 18, 50]. For semantic segmentation, we report " + }, + { + "bbox": [ + 305, + 162, + 545, + 234 + ], + "type": "inline_equation", + "content": "mIoU" + }, + { + "bbox": [ + 305, + 162, + 545, + 234 + ], + "type": "text", + "content": " (mean intersection-over-union) [11] for evaluation. For panoptic segmentation, we report " + }, + { + "bbox": [ + 305, + 162, + 545, + 234 + ], + "type": "inline_equation", + "content": "PQ" + }, + { + "bbox": [ + 305, + 162, + 545, + 234 + ], + "type": "text", + "content": " (panoptic quality) [22]." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 243, + 438, + 256 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 243, + 438, + 256 + ], + "spans": [ + { + "bbox": [ + 306, + 243, + 438, + 256 + ], + "type": "text", + "content": "5.2. Implementation Details" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 305, + 262, + 545, + 369 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 262, + 545, + 369 + ], + "spans": [ + { + "bbox": [ + 305, + 262, + 545, + 369 + ], + "type": "text", + "content": "Class-Agnostic Mask Proposal Network. We train Mask2Former [7] or Mask R-CNN [14] with ResNet-50 backbone to generate class-agnostic mask proposals. The labels of masks are not used as supervision, and the number of mask proposals for each image is set to 100 for both models. In Mask2Former, the number of classes is set to 1 to obtain the object score. In Mask R-CNN, we adopt the confidence scores of the RPN head as object scores. The default experiment setting for Mask R-CNN is R50-FPN-1x." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 373, + 545, + 492 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 373, + 545, + 492 + ], + "spans": [ + { + "bbox": [ + 305, + 373, + 545, + 492 + ], + "type": "text", + "content": "Progressive Distillation. For Mask2Former, we first train the initial teacher model until convergence. Then, we retrain the student model for 2 rounds with 30k iterations each round (under both settings). Unless stated, other experiment settings are set to default as training Mask2Former [7]. For Mask R-CNN, we use the checkpoint of R50-FPN-1x as the initial teacher model. We then re-train the student model for 2 rounds with 10k iterations each round (under both settings). For all models and settings, we set the threshold of object scores " + }, + { + "bbox": [ + 305, + 373, + 545, + 492 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 305, + 373, + 545, + 492 + ], + "type": "text", + "content": " to 0.8, and the NMS threshold " + }, + { + "bbox": [ + 305, + 373, + 545, + 492 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 305, + 373, + 545, + 492 + ], + "type": "text", + "content": " to 0.1." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 305, + 495, + 545, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 495, + 545, + 687 + ], + "spans": [ + { + "bbox": [ + 305, + 495, + 545, + 687 + ], + "type": "text", + "content": "MasQ-Tuning. During fine-tuning, we use the same CLIP model ViT-L/14@336px as in [9]. The language descriptors are simply the text embeddings of category names given by the language encoder of CLIP without any prompt. The number of Mask Class Tokens is set to 100 which is equivalent to the number of mask proposals. The query projection " + }, + { + "bbox": [ + 305, + 495, + 545, + 687 + ], + "type": "inline_equation", + "content": "f_{Q}^{\\prime}" + }, + { + "bbox": [ + 305, + 495, + 545, + 687 + ], + "type": "text", + "content": " at each layer exhibits the same architecture of a linear projection as the original " + }, + { + "bbox": [ + 305, + 495, + 545, + 687 + ], + "type": "inline_equation", + "content": "f_{Q}" + }, + { + "bbox": [ + 305, + 495, + 545, + 687 + ], + "type": "text", + "content": " in CLIP visual encoder. In both cross-dataset and base-novel settings, we use AdamW [26] as our default optimizer and the initial learning rate is set to 0.0001. We assign a predicted mask a label if it has an IoU higher than 0.6 with a ground-truth mask. We fine-tune for 10k iterations with a batch size of 4, and the learning rate is decreased by a factor of 10 at 9k iterations. During inference, the post-processing follows Mask2Former after obtaining labels for mask proposals." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": "Settings. For each model architecture (Mask R-CNN or Mask2Former), we train two MasQCLIP models for base-" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 297, + 749, + 311, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 749, + 311, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 749, + 311, + 757 + ], + "type": "text", + "content": "891" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 51, + 69, + 541, + 180 + ], + "blocks": [ + { + "bbox": [ + 51, + 69, + 541, + 180 + ], + "lines": [ + { + "bbox": [ + 51, + 69, + 541, + 180 + ], + "spans": [ + { + "bbox": [ + 51, + 69, + 541, + 180 + ], + "type": "table", + "html": "
MethodsBackboneInstanceSemanticPanoptic
BaseNovelAllA-150A-847P-59P-459PQ\\( PQ^{th} \\)\\( PQ^{st} \\)
XPM [18]ResNet-5041.521.636.3-------
LSeg+ [23]EffNet-B7---18.03.846.57.8---
OpenSeg [12]EffNet-B7---21.16.342.19.0---
MaskCLIP (Mask R-CNN) [9]ResNet-50---22.46.841.39.112.911.216.1
MaskCLIP (Mask2Former) [9]ResNet-50---23.78.245.910.015.113.518.3
MasQCLIP (Mask R-CNN)ResNet-5040.728.437.523.78.444.414.114.914.515.6
MasQCLIP (Mask2Former)ResNet-5051.031.946.030.410.757.818.223.321.227.7
+9.5+10.3+9.7+6.7+2.5+11.3+8.2+8.2+7.7+9.4
", + "image_path": "d78c5f656a96dfa12235597a431cbb76bd30aaad80c08989ef1d6348de5aa241.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 51, + 274, + 281, + 362 + ], + "blocks": [ + { + "bbox": [ + 46, + 184, + 547, + 263 + ], + "lines": [ + { + "bbox": [ + 46, + 184, + 547, + 263 + ], + "spans": [ + { + "bbox": [ + 46, + 184, + 547, + 263 + ], + "type": "text", + "content": "Table 1: Results on open-vocabulary universal image segmentation. We compare MasQCLIP with state-of-the-art models on three segmentation tasks with a universal architecture. We use Mask R-CNN or Mask2Former as our class-agnostic mask proposal network. All methods in the table rely only on COCO dataset for training. a) For instance segmentation, we report mask AP50 following base-novel setting [18]. b) For semantic segmentation, we report mIoU on ADE20k and PASCAL-Context following cross-dataset setting [20]. A-150 and A-847 represent ADE20k with 150 classes and 847 classes respectively. P-59 and P-459 represent PASCAL-Context with 59 classes and 459 classes respectively. c) For panoptic segmentation, we report " + }, + { + "bbox": [ + 46, + 184, + 547, + 263 + ], + "type": "inline_equation", + "content": "PQ" + }, + { + "bbox": [ + 46, + 184, + 547, + 263 + ], + "type": "text", + "content": " on ADE20k following cross-dataset setting [9]. We achieve significant improvements on all evaluation metrics." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 51, + 274, + 281, + 362 + ], + "lines": [ + { + "bbox": [ + 51, + 274, + 281, + 362 + ], + "spans": [ + { + "bbox": [ + 51, + 274, + 281, + 362 + ], + "type": "table", + "html": "
MethodsConstrainedGeneralized
BaseNovelBaseNovelAll
OVR [50]42.020.941.617.135.2
SB [1]41.620.841.016.034.5
BA-RPN [54]41.820.141.315.434.5
OVR+OMP [2]31.314.130.58.324.7
XPM [18]42.424.041.521.636.3
MasQCLIP (Mask R-CNN)40.930.140.728.437.5
MasQCLIP (Mask2Former)51.234.351.031.946.0
", + "image_path": "69449e0ab9a0972b238a6c8ed9ad0328164ba539937d087b5254cfb2d7c51d2d.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 365, + 287, + 443 + ], + "lines": [ + { + "bbox": [ + 46, + 365, + 287, + 443 + ], + "spans": [ + { + "bbox": [ + 46, + 365, + 287, + 443 + ], + "type": "text", + "content": "Table 2: Results on open-vocabulary instance segmentation. We report mask AP50 in the table. The results presented in the table all use the ResNet-50 backbone. Constrained setting means that the model is evaluated on either base classes or novel classes separately. Generalized setting means that the model is tested jointly on both base and novel classes. Notice that the results of novel classes show the generalization ability of models." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 459, + 287, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 459, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 46, + 459, + 287, + 533 + ], + "type": "text", + "content": "novel and cross-dataset settings separately. The former model is trained on base classes of COCO-instance dataset and is tested on novel classes (for instance segmentation), while the latter is trained on the COCO-panoptic dataset and is used for both semantic (through post-possessing) and panoptic segmentation evaluation." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 539, + 132, + 551 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 539, + 132, + 551 + ], + "spans": [ + { + "bbox": [ + 47, + 539, + 132, + 551 + ], + "type": "text", + "content": "5.3. Main Results" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 557, + 288, + 715 + ], + "type": "text", + "content": "Instance Segmentation. We evaluate our MasQCLIP on instance segmentation under base-novel setting. We first train MasQCLIP on base classes of COCO-instance dataset and then evaluate the model on novel classes. The detailed results are presented in Tab. 2. As shown, when using Mask R-CNN as our class-agnostic mask proposal network, we achieve an improvement of 6.8 AP50 on novel classes over XPM [18]. When using Mask2Former, we further achieve an improvement of 10.3 AP50. The evaluation metrics on novel classes mainly reflect the generalization ability of models. Since our relative improvement on novel classes is much higher than that on base classes across two mask proposal networks, our proposed method enjoys better gen" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 277, + 497, + 289 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 277, + 497, + 289 + ], + "spans": [ + { + "bbox": [ + 305, + 277, + 497, + 289 + ], + "type": "text", + "content": "eralization ability compared to previous works." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 292, + 545, + 388 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 292, + 545, + 388 + ], + "spans": [ + { + "bbox": [ + 304, + 292, + 545, + 388 + ], + "type": "text", + "content": "Semantic Segmentation. We evaluate our MasQCLIP on semantic segmentation under cross-dataset setting. We directly use the model trained on COCO-panoptic dataset for evaluation, and report the results on ADE20ksemantic and PASCAL-Context-semantic datasets in Tab. 1. In terms of " + }, + { + "bbox": [ + 304, + 292, + 545, + 388 + ], + "type": "inline_equation", + "content": "mIoU" + }, + { + "bbox": [ + 304, + 292, + 545, + 388 + ], + "type": "text", + "content": ", MasQCLIP improves previous state-of-the-art results by 6.7, 2.5, 11.3, and 8.2 on A-150, A-847, P-59, and P-459 datasets respectively." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 391, + 546, + 510 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 391, + 546, + 510 + ], + "spans": [ + { + "bbox": [ + 304, + 391, + 546, + 510 + ], + "type": "text", + "content": "Panoptic Segmentation. We evaluate our MasQCLIP on panoptic segmentation under cross-dataset setting. We first train MasQCLIP on COCO-panoptic dataset, and then directly evaluate the model on ADE20k-panoptic dataset. The results are presented in Tab. 1. As shown, when using the same mask proposal network architecture, MasQCLIP outperforms state-of-the-art MaskCLIP [9] by " + }, + { + "bbox": [ + 304, + 391, + 546, + 510 + ], + "type": "inline_equation", + "content": "8.2PQ" + }, + { + "bbox": [ + 304, + 391, + 546, + 510 + ], + "type": "text", + "content": ". Even adopted with a weaker mask proposal network of Mask R-CNN, MasQCLIP still achieves on-par results on " + }, + { + "bbox": [ + 304, + 391, + 546, + 510 + ], + "type": "inline_equation", + "content": "PQ" + }, + { + "bbox": [ + 304, + 391, + 546, + 510 + ], + "type": "text", + "content": " compared with MaskCLIP." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 517, + 406, + 529 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 517, + 406, + 529 + ], + "spans": [ + { + "bbox": [ + 306, + 517, + 406, + 529 + ], + "type": "text", + "content": "5.4. Ablation Studies" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 536, + 437, + 548 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 536, + 437, + 548 + ], + "spans": [ + { + "bbox": [ + 306, + 536, + 437, + 548 + ], + "type": "text", + "content": "5.4.1 Progressive Distillation" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 555, + 545, + 626 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 555, + 545, + 626 + ], + "spans": [ + { + "bbox": [ + 304, + 555, + 545, + 626 + ], + "type": "text", + "content": "In this section, we conduct ablation studies on progressive distillation. We evaluate the models on instance segmentation under base-novel setting. The initial teacher model is trained for 100k iterations on base annotations, and the student model is then re-trained for 30k iterations each round using the initial teacher model." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 546, + 715 + ], + "type": "text", + "content": "Object Scores. We first study the importance of object scores. As shown in Tab. 3, incorporating object scores boosts performance on base classes and novel classes significantly. In addition, despite object scores being trained only on base classes, they still serve as reliable indicators of mask quality for novel classes, which demonstrates the generalization of object scores. The results show that it is" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "text", + "content": "892" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 92, + 70, + 193, + 147 + ], + "blocks": [ + { + "bbox": [ + 92, + 70, + 193, + 147 + ], + "lines": [ + { + "bbox": [ + 92, + 70, + 193, + 147 + ], + "spans": [ + { + "bbox": [ + 92, + 70, + 193, + 147 + ], + "type": "image", + "image_path": "313b2598d8e2a93ef81219129097882bc911056c80d7f9e561f337e1827356ea.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 92, + 148, + 193, + 213 + ], + "blocks": [ + { + "bbox": [ + 92, + 148, + 193, + 213 + ], + "lines": [ + { + "bbox": [ + 92, + 148, + 193, + 213 + ], + "spans": [ + { + "bbox": [ + 92, + 148, + 193, + 213 + ], + "type": "image", + "image_path": "e0a89c9733dc265e7db936459ae396452221a8c27c925d77f123b0e9c59fc333.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 130, + 216, + 154, + 227 + ], + "lines": [ + { + "bbox": [ + 130, + 216, + 154, + 227 + ], + "spans": [ + { + "bbox": [ + 130, + 216, + 154, + 227 + ], + "type": "text", + "content": "Input" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 194, + 70, + 294, + 147 + ], + "blocks": [ + { + "bbox": [ + 194, + 70, + 294, + 147 + ], + "lines": [ + { + "bbox": [ + 194, + 70, + 294, + 147 + ], + "spans": [ + { + "bbox": [ + 194, + 70, + 294, + 147 + ], + "type": "image", + "image_path": "54317b5d8c1e37f4a15068dca94d6f7e13f44ebcf8154bf3f679c8596757d0f4.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 194, + 148, + 294, + 213 + ], + "blocks": [ + { + "bbox": [ + 194, + 148, + 294, + 213 + ], + "lines": [ + { + "bbox": [ + 194, + 148, + 294, + 213 + ], + "spans": [ + { + "bbox": [ + 194, + 148, + 294, + 213 + ], + "type": "image", + "image_path": "3208962849aacd0762c7b8e43731159c023146899a265dad3b439e528045c51d.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 219, + 216, + 279, + 226 + ], + "lines": [ + { + "bbox": [ + 219, + 216, + 279, + 226 + ], + "spans": [ + { + "bbox": [ + 219, + 216, + 279, + 226 + ], + "type": "text", + "content": "CLIP Baseline" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 232, + 545, + 255 + ], + "lines": [ + { + "bbox": [ + 46, + 232, + 545, + 255 + ], + "spans": [ + { + "bbox": [ + 46, + 232, + 545, + 255 + ], + "type": "text", + "content": "Figure 4: Comparison on open-vocabulary instance segmentation. We evaluate on the same set of images as in MaskCLIP [9]. The above two images are from ADE20k dataset. Visualization results show that our mask proposals are more robust and high-quality." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 295, + 70, + 396, + 147 + ], + "blocks": [ + { + "bbox": [ + 295, + 70, + 396, + 147 + ], + "lines": [ + { + "bbox": [ + 295, + 70, + 396, + 147 + ], + "spans": [ + { + "bbox": [ + 295, + 70, + 396, + 147 + ], + "type": "image", + "image_path": "572f3d55c09644ae6cd336af6ac07b736837baf2c4874ebe1959c08ed61ff70b.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 295, + 148, + 396, + 213 + ], + "blocks": [ + { + "bbox": [ + 295, + 148, + 396, + 213 + ], + "lines": [ + { + "bbox": [ + 295, + 148, + 396, + 213 + ], + "spans": [ + { + "bbox": [ + 295, + 148, + 396, + 213 + ], + "type": "image", + "image_path": "9034916a48c684023c3344336d5543641ddbb23bc8173796a8d551336229689d.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 328, + 216, + 374, + 226 + ], + "lines": [ + { + "bbox": [ + 328, + 216, + 374, + 226 + ], + "spans": [ + { + "bbox": [ + 328, + 216, + 374, + 226 + ], + "type": "text", + "content": "MaskCLIP" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 399, + 70, + 500, + 147 + ], + "blocks": [ + { + "bbox": [ + 399, + 70, + 500, + 147 + ], + "lines": [ + { + "bbox": [ + 399, + 70, + 500, + 147 + ], + "spans": [ + { + "bbox": [ + 399, + 70, + 500, + 147 + ], + "type": "image", + "image_path": "2e780436b55f5dacb84bf19b4ff34962246516e3544187e181bc99d60a18b2d9.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 399, + 148, + 499, + 213 + ], + "blocks": [ + { + "bbox": [ + 399, + 148, + 499, + 213 + ], + "lines": [ + { + "bbox": [ + 399, + 148, + 499, + 213 + ], + "spans": [ + { + "bbox": [ + 399, + 148, + 499, + 213 + ], + "type": "image", + "image_path": "85ac3f211955747f2d606f5a8df7bcea7ef09ca40c580bfcc77655624680a025.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 429, + 216, + 477, + 227 + ], + "lines": [ + { + "bbox": [ + 429, + 216, + 477, + 227 + ], + "spans": [ + { + "bbox": [ + 429, + 216, + 477, + 227 + ], + "type": "text", + "content": "MasQCLIP" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 74, + 266, + 261, + 301 + ], + "blocks": [ + { + "bbox": [ + 74, + 266, + 261, + 301 + ], + "lines": [ + { + "bbox": [ + 74, + 266, + 261, + 301 + ], + "spans": [ + { + "bbox": [ + 74, + 266, + 261, + 301 + ], + "type": "table", + "html": "
ModelsScoresBaseNovelAll
Mask2Former-16.911.315.4
Mask2Former✓53.822.645.6
", + "image_path": "f86d4390dfdfe0327925a621c68241159b083ca99dc9b2fa176482a077595263.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_body" + } + ], + "index": 13 + }, + { + "type": "table", + "bbox": [ + 82, + 354, + 253, + 423 + ], + "blocks": [ + { + "bbox": [ + 46, + 304, + 287, + 348 + ], + "lines": [ + { + "bbox": [ + 46, + 304, + 287, + 348 + ], + "spans": [ + { + "bbox": [ + 46, + 304, + 287, + 348 + ], + "type": "text", + "content": "Table 3: Ablations on Object Scores. We report mask AP50 in the table. Models denote the architecture of class-agnostic mask proposal networks. Scores denote whether we incorporate object scores." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 82, + 354, + 253, + 423 + ], + "lines": [ + { + "bbox": [ + 82, + 354, + 253, + 423 + ], + "spans": [ + { + "bbox": [ + 82, + 354, + 253, + 423 + ], + "type": "table", + "html": "
TeacherStudentBaseNovelAll
100k-53.822.645.6
100k30k×150.626.144.2
100k30k×251.031.946.0
100k30k×351.231.246.0
200k-54.718.245.1
", + "image_path": "0a73c7feae376aad2471b912355d04111b35e06b27cd1988a08d8985452a488e.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "table_body" + } + ], + "index": 15 + }, + { + "bbox": [ + 46, + 495, + 287, + 519 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 495, + 287, + 519 + ], + "spans": [ + { + "bbox": [ + 46, + 495, + 287, + 519 + ], + "type": "text", + "content": "reasonable to consider object scores as a general indicator of mask quality." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 46, + 521, + 287, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 521, + 287, + 616 + ], + "spans": [ + { + "bbox": [ + 46, + 521, + 287, + 616 + ], + "type": "text", + "content": "Iterative Re-training. Tab. 4 shows the effectiveness of progressive distillation. After we train the student model for 2 rounds progressively, the model performance improves on novel classes by 9.3 AP50. Although the results manifest a slight performance drop on base classes, it can be explained that the model is balancing between the base and extra (novel) annotations, thus leading the model to be less overfitted on base classes." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "text", + "content": "If we continue to train the student model for more rounds (e.g. 3 rounds), the model does not gain further improvement in generalization ability, indicating that there might exist an upper bound for the progressive distillation process. In addition, we also show that the improvement on novel classes cannot simply gain from a longer training schedule. When training the network for another 100k iterations without progressive distillation, there is a notable performance" + } + ] + } + ], + "index": 19 + }, + { + "type": "table", + "bbox": [ + 308, + 266, + 547, + 347 + ], + "blocks": [ + { + "bbox": [ + 46, + 426, + 287, + 482 + ], + "lines": [ + { + "bbox": [ + 46, + 426, + 287, + 482 + ], + "spans": [ + { + "bbox": [ + 46, + 426, + 287, + 482 + ], + "type": "text", + "content": "Table 4: Ablations on Iterative Re-training. We report mask AP50 in the table. We adopt the Mask2Former architecture and incorporate object scores by default. Teacher denotes the training iterations of the initial teacher model, and Student denotes how we train the student model progressively." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 308, + 266, + 547, + 347 + ], + "lines": [ + { + "bbox": [ + 308, + 266, + 547, + 347 + ], + "spans": [ + { + "bbox": [ + 308, + 266, + 547, + 347 + ], + "type": "table", + "html": "
MethodsQKVAllParamADE20kCOCO
PQmIoUPQmIoU
Freeze-----10.715.719.422.1
Tune-V--✓-25M14.418.050.063.2
Tune-QKV✓✓✓-75M14.918.650.563.5
Tune-CLIP✓✓✓✓304M14.718.349.063.6
Tune-K-✓--25M22.529.848.361.6
Tune-QK✓✓--50M22.930.149.062.3
Tune-Q (ours)✓---25M23.330.448.562.0
", + "image_path": "f6cd14320b0babf03e8417f71d716fbaf2dc9d4e8a89a4f03c64ac23ea0192a6.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "table_body" + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 351, + 547, + 440 + ], + "lines": [ + { + "bbox": [ + 304, + 351, + 547, + 440 + ], + "spans": [ + { + "bbox": [ + 304, + 351, + 547, + 440 + ], + "type": "text", + "content": "Table 5: Ablations on MasQ-Tuning. We try different fine-tuning strategies. " + }, + { + "bbox": [ + 304, + 351, + 547, + 440 + ], + "type": "inline_equation", + "content": "Q, K, V" + }, + { + "bbox": [ + 304, + 351, + 547, + 440 + ], + "type": "text", + "content": " means the newly added query, key, and value projections for Mask Class Tokens respectively, and All means all the newly added parameters (also including layernorm, FFN, and the final projection). Param denotes the total number of trainable parameters. The models are first trained on COCO and then evaluated on ADE20k. We note that the metrics on ADE20k mainly show the generalization ability." + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 453, + 545, + 489 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 453, + 545, + 489 + ], + "spans": [ + { + "bbox": [ + 304, + 453, + 545, + 489 + ], + "type": "text", + "content": "drop of 4.4 AP50 (from 22.6 to 18.2) on novel classes. Our observation supports that improvement of model performance indeed comes from progressive distillation." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 306, + 500, + 399, + 512 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 500, + 399, + 512 + ], + "spans": [ + { + "bbox": [ + 306, + 500, + 399, + 512 + ], + "type": "text", + "content": "5.4.2 MasQ-Tuning" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 304, + 519, + 545, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 519, + 545, + 544 + ], + "spans": [ + { + "bbox": [ + 304, + 519, + 545, + 544 + ], + "type": "text", + "content": "To validate our fine-tuning method, MasQ-Tuning, we build several baselines to prove its effectiveness." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 317, + 555, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 31, + "blocks": [ + { + "bbox": [ + 317, + 555, + 545, + 578 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 555, + 545, + 578 + ], + "spans": [ + { + "bbox": [ + 317, + 555, + 545, + 578 + ], + "type": "text", + "content": "- Freeze: Same as the MaskCLIP w/o RMA baseline in [9]. We incorporate object scores during inference." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 317, + 582, + 545, + 617 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 582, + 545, + 617 + ], + "spans": [ + { + "bbox": [ + 317, + 582, + 545, + 617 + ], + "type": "text", + "content": "- Tune-Q: Only query projections " + }, + { + "bbox": [ + 317, + 582, + 545, + 617 + ], + "type": "inline_equation", + "content": "f_{Q}^{\\prime}" + }, + { + "bbox": [ + 317, + 582, + 545, + 617 + ], + "type": "text", + "content": " for Mask Class Tokens are learnable during fine-tuning. Notice that MasQCLIP adopts this fine-tuning strategy." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 317, + 620, + 545, + 644 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 620, + 545, + 644 + ], + "spans": [ + { + "bbox": [ + 317, + 620, + 545, + 644 + ], + "type": "text", + "content": "- Tune-K: Only key projections " + }, + { + "bbox": [ + 317, + 620, + 545, + 644 + ], + "type": "inline_equation", + "content": "f_{K}^{\\prime}" + }, + { + "bbox": [ + 317, + 620, + 545, + 644 + ], + "type": "text", + "content": " for Mask Class Tokens are learnable during fine-tuning." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 317, + 647, + 545, + 671 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 647, + 545, + 671 + ], + "spans": [ + { + "bbox": [ + 317, + 647, + 545, + 671 + ], + "type": "text", + "content": "- Tune-V: Only value projections " + }, + { + "bbox": [ + 317, + 647, + 545, + 671 + ], + "type": "inline_equation", + "content": "f_V'" + }, + { + "bbox": [ + 317, + 647, + 545, + 671 + ], + "type": "text", + "content": " for Mask Class Tokens are learnable during fine-tuning." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 317, + 674, + 545, + 699 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 674, + 545, + 699 + ], + "spans": [ + { + "bbox": [ + 317, + 674, + 545, + 699 + ], + "type": "text", + "content": "- Tune-QK: Query and key projections for Mask Class Tokens (" + }, + { + "bbox": [ + 317, + 674, + 545, + 699 + ], + "type": "inline_equation", + "content": "f_{Q}^{\\prime}" + }, + { + "bbox": [ + 317, + 674, + 545, + 699 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 317, + 674, + 545, + 699 + ], + "type": "inline_equation", + "content": "f_{K}^{\\prime}" + }, + { + "bbox": [ + 317, + 674, + 545, + 699 + ], + "type": "text", + "content": "), are learnable during fine-tuning." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 317, + 701, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 701, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 317, + 701, + 545, + 713 + ], + "type": "text", + "content": "- Tune-QKV: Query, key, and value projections for Mask" + } + ] + } + ], + "index": 30 + } + ], + "sub_type": "text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "text", + "content": "893" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 91, + 69, + 173, + 133 + ], + "blocks": [ + { + "bbox": [ + 91, + 69, + 173, + 133 + ], + "lines": [ + { + "bbox": [ + 91, + 69, + 173, + 133 + ], + "spans": [ + { + "bbox": [ + 91, + 69, + 173, + 133 + ], + "type": "image", + "image_path": "29e008b61647159925c30af0ffcc4d05b79eb02dd04c4bdccf4cb4b71dccc4e9.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 118, + 135, + 146, + 145 + ], + "lines": [ + { + "bbox": [ + 118, + 135, + 146, + 145 + ], + "spans": [ + { + "bbox": [ + 118, + 135, + 146, + 145 + ], + "type": "text", + "content": "Image" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 173, + 70, + 255, + 132 + ], + "blocks": [ + { + "bbox": [ + 173, + 70, + 255, + 132 + ], + "lines": [ + { + "bbox": [ + 173, + 70, + 255, + 132 + ], + "spans": [ + { + "bbox": [ + 173, + 70, + 255, + 132 + ], + "type": "image", + "image_path": "c9ee995dd2f5f6cd624bc90b42f9c8795fd83b747eb8b1c1d655b73ced7394a3.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 207, + 134, + 222, + 144 + ], + "lines": [ + { + "bbox": [ + 207, + 134, + 222, + 144 + ], + "spans": [ + { + "bbox": [ + 207, + 134, + 222, + 144 + ], + "type": "text", + "content": "GT" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 137, + 146, + 155, + 163 + ], + "blocks": [ + { + "bbox": [ + 137, + 146, + 155, + 163 + ], + "lines": [ + { + "bbox": [ + 137, + 146, + 155, + 163 + ], + "spans": [ + { + "bbox": [ + 137, + 146, + 155, + 163 + ], + "type": "image", + "image_path": "422cac3ac5120310d831aa4bb764aedc65d05a7e53068950b0f06290d41666ef.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 137, + 165, + 156, + 173 + ], + "lines": [ + { + "bbox": [ + 137, + 165, + 156, + 173 + ], + "spans": [ + { + "bbox": [ + 137, + 165, + 156, + 173 + ], + "type": "text", + "content": "house" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 161, + 147, + 178, + 163 + ], + "blocks": [ + { + "bbox": [ + 161, + 147, + 178, + 163 + ], + "lines": [ + { + "bbox": [ + 161, + 147, + 178, + 163 + ], + "spans": [ + { + "bbox": [ + 161, + 147, + 178, + 163 + ], + "type": "image", + "image_path": "ed4b982c7f9fefc00ff85cb98088f945140039c89882a4c38735aa4f66417545.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 161, + 165, + 178, + 173 + ], + "lines": [ + { + "bbox": [ + 161, + 165, + 178, + 173 + ], + "spans": [ + { + "bbox": [ + 161, + 165, + 178, + 173 + ], + "type": "text", + "content": "sky" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 207, + 147, + 223, + 163 + ], + "blocks": [ + { + "bbox": [ + 207, + 147, + 223, + 163 + ], + "lines": [ + { + "bbox": [ + 207, + 147, + 223, + 163 + ], + "spans": [ + { + "bbox": [ + 207, + 147, + 223, + 163 + ], + "type": "image", + "image_path": "49d16f5694885bde193c79b80dea69cf70b010cd617cf4fa43322100ca33c03e.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 207, + 165, + 223, + 173 + ], + "lines": [ + { + "bbox": [ + 207, + 165, + 223, + 173 + ], + "spans": [ + { + "bbox": [ + 207, + 165, + 223, + 173 + ], + "type": "text", + "content": "grass" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 229, + 147, + 252, + 163 + ], + "blocks": [ + { + "bbox": [ + 229, + 147, + 252, + 163 + ], + "lines": [ + { + "bbox": [ + 229, + 147, + 252, + 163 + ], + "spans": [ + { + "bbox": [ + 229, + 147, + 252, + 163 + ], + "type": "image", + "image_path": "3c2f713d9f68e5ab6f0e1e8f31fb6f2656fd4268153f2952262a1cf7b912a135.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 230, + 165, + 246, + 173 + ], + "lines": [ + { + "bbox": [ + 230, + 165, + 246, + 173 + ], + "spans": [ + { + "bbox": [ + 230, + 165, + 246, + 173 + ], + "type": "text", + "content": "land" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 256, + 71, + 337, + 132 + ], + "blocks": [ + { + "bbox": [ + 256, + 71, + 337, + 132 + ], + "lines": [ + { + "bbox": [ + 256, + 71, + 337, + 132 + ], + "spans": [ + { + "bbox": [ + 256, + 71, + 337, + 132 + ], + "type": "image", + "image_path": "31aebb737ea92b16ef61f274aefa707f46dd53e5ee69a417188e38d8f1912c95.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 277, + 134, + 315, + 145 + ], + "lines": [ + { + "bbox": [ + 277, + 134, + 315, + 145 + ], + "spans": [ + { + "bbox": [ + 277, + 134, + 315, + 145 + ], + "type": "text", + "content": "OpenSeg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 253, + 147, + 274, + 163 + ], + "blocks": [ + { + "bbox": [ + 253, + 147, + 274, + 163 + ], + "lines": [ + { + "bbox": [ + 253, + 147, + 274, + 163 + ], + "spans": [ + { + "bbox": [ + 253, + 147, + 274, + 163 + ], + "type": "image", + "image_path": "c62cfde2fdd1b598da2edb3d8e9bdaa2d327f5111dd905ee30a085df749e0c51.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 253, + 165, + 274, + 173 + ], + "lines": [ + { + "bbox": [ + 253, + 165, + 274, + 173 + ], + "spans": [ + { + "bbox": [ + 253, + 165, + 274, + 173 + ], + "type": "text", + "content": "tree" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 276, + 147, + 293, + 163 + ], + "blocks": [ + { + "bbox": [ + 276, + 147, + 293, + 163 + ], + "lines": [ + { + "bbox": [ + 276, + 147, + 293, + 163 + ], + "spans": [ + { + "bbox": [ + 276, + 147, + 293, + 163 + ], + "type": "image", + "image_path": "14c9ed297be81d46341daade677991558b74bd8fa70f8538ff260f73bfd733ed.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 276, + 165, + 291, + 173 + ], + "lines": [ + { + "bbox": [ + 276, + 165, + 291, + 173 + ], + "spans": [ + { + "bbox": [ + 276, + 165, + 291, + 173 + ], + "type": "text", + "content": "brick" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_caption" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 304, + 147, + 326, + 163 + ], + "blocks": [ + { + "bbox": [ + 304, + 147, + 326, + 163 + ], + "lines": [ + { + "bbox": [ + 304, + 147, + 326, + 163 + ], + "spans": [ + { + "bbox": [ + 304, + 147, + 326, + 163 + ], + "type": "image", + "image_path": "4767cb8d94d69026d060968c9e94fbdad6e1875cd20f7a9a07ce64f282666896.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 165, + 315, + 173 + ], + "lines": [ + { + "bbox": [ + 304, + 165, + 315, + 173 + ], + "spans": [ + { + "bbox": [ + 304, + 165, + 315, + 173 + ], + "type": "text", + "content": "ock" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 321, + 147, + 337, + 163 + ], + "blocks": [ + { + "bbox": [ + 321, + 147, + 337, + 163 + ], + "lines": [ + { + "bbox": [ + 321, + 147, + 337, + 163 + ], + "spans": [ + { + "bbox": [ + 321, + 147, + 337, + 163 + ], + "type": "image", + "image_path": "dae54618c3189131fa900dd38c9e3c11a70ac4964b8bc16101c92cfba907e167.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 322, + 165, + 337, + 173 + ], + "lines": [ + { + "bbox": [ + 322, + 165, + 337, + 173 + ], + "spans": [ + { + "bbox": [ + 322, + 165, + 337, + 173 + ], + "type": "text", + "content": "river" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_caption" + } + ], + "index": 20 + }, + { + "type": "image", + "bbox": [ + 339, + 71, + 419, + 132 + ], + "blocks": [ + { + "bbox": [ + 339, + 71, + 419, + 132 + ], + "lines": [ + { + "bbox": [ + 339, + 71, + 419, + 132 + ], + "spans": [ + { + "bbox": [ + 339, + 71, + 419, + 132 + ], + "type": "image", + "image_path": "5a6ffaf4dc89589dc4117b50e80f759f33865dcb0be9887b9b1d99843fe8af41.jpg" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 356, + 134, + 402, + 144 + ], + "lines": [ + { + "bbox": [ + 356, + 134, + 402, + 144 + ], + "spans": [ + { + "bbox": [ + 356, + 134, + 402, + 144 + ], + "type": "text", + "content": "MaskCLIP" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_caption" + } + ], + "index": 22 + }, + { + "type": "image", + "bbox": [ + 339, + 147, + 361, + 163 + ], + "blocks": [ + { + "bbox": [ + 339, + 147, + 361, + 163 + ], + "lines": [ + { + "bbox": [ + 339, + 147, + 361, + 163 + ], + "spans": [ + { + "bbox": [ + 339, + 147, + 361, + 163 + ], + "type": "image", + "image_path": "90077c89a02487a4c495d86a97598ae827e51329031f219f73eecee02dd4980b.jpg" + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 339, + 165, + 359, + 173 + ], + "lines": [ + { + "bbox": [ + 339, + 165, + 359, + 173 + ], + "spans": [ + { + "bbox": [ + 339, + 165, + 359, + 173 + ], + "type": "text", + "content": "wall" + } + ] + } + ], + "index": 25, + "angle": 0, + "type": "image_caption" + } + ], + "index": 24 + }, + { + "type": "image", + "bbox": [ + 364, + 147, + 390, + 163 + ], + "blocks": [ + { + "bbox": [ + 364, + 147, + 390, + 163 + ], + "lines": [ + { + "bbox": [ + 364, + 147, + 390, + 163 + ], + "spans": [ + { + "bbox": [ + 364, + 147, + 390, + 163 + ], + "type": "image", + "image_path": "9aae7d2abfecf5281161ab17e99d0b777f0bda5d5c7dfc7050930dc2d0d2501e.jpg" + } + ] + } + ], + "index": 26, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 364, + 165, + 390, + 173 + ], + "lines": [ + { + "bbox": [ + 364, + 165, + 390, + 173 + ], + "spans": [ + { + "bbox": [ + 364, + 165, + 390, + 173 + ], + "type": "text", + "content": "building" + } + ] + } + ], + "index": 27, + "angle": 0, + "type": "image_caption" + } + ], + "index": 26 + }, + { + "bbox": [ + 405, + 71, + 419, + 132 + ], + "angle": 0, + "lines": [ + { + "bbox": [ + 405, + 71, + 419, + 132 + ], + "spans": [ + { + "bbox": [ + 405, + 71, + 419, + 132 + ], + "type": "image", + "image_path": "536f0efaca6ee3a018aa89f47f4ae9cbc41303937a6af887f1f658b0d0079bb5.jpg" + } + ] + } + ], + "index": 28, + "type": "text" + }, + { + "type": "image", + "bbox": [ + 405, + 147, + 426, + 163 + ], + "blocks": [ + { + "bbox": [ + 405, + 147, + 426, + 163 + ], + "lines": [ + { + "bbox": [ + 405, + 147, + 426, + 163 + ], + "spans": [ + { + "bbox": [ + 405, + 147, + 426, + 163 + ], + "type": "image", + "image_path": "983d8498e627fdbb9ab465ed7b2474086d52a205df4853d91058b4432c7ed43d.jpg" + } + ] + } + ], + "index": 29, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 405, + 165, + 423, + 173 + ], + "lines": [ + { + "bbox": [ + 405, + 165, + 423, + 173 + ], + "spans": [ + { + "bbox": [ + 405, + 165, + 423, + 173 + ], + "type": "text", + "content": "roo" + } + ] + } + ], + "index": 30, + "angle": 0, + "type": "image_caption" + } + ], + "index": 29 + }, + { + "type": "image", + "bbox": [ + 422, + 71, + 503, + 132 + ], + "blocks": [ + { + "bbox": [ + 422, + 71, + 503, + 132 + ], + "lines": [ + { + "bbox": [ + 422, + 71, + 503, + 132 + ], + "spans": [ + { + "bbox": [ + 422, + 71, + 503, + 132 + ], + "type": "image", + "image_path": "da3d4621a4abc798c79151be251343545a3a1620ca1b6dcd21390e1be7fd8580.jpg" + } + ] + } + ], + "index": 31, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 438, + 134, + 485, + 145 + ], + "lines": [ + { + "bbox": [ + 438, + 134, + 485, + 145 + ], + "spans": [ + { + "bbox": [ + 438, + 134, + 485, + 145 + ], + "type": "text", + "content": "MasQCLIP" + } + ] + } + ], + "index": 32, + "angle": 0, + "type": "image_caption" + } + ], + "index": 31 + }, + { + "type": "image", + "bbox": [ + 422, + 147, + 451, + 163 + ], + "blocks": [ + { + "bbox": [ + 422, + 147, + 451, + 163 + ], + "lines": [ + { + "bbox": [ + 422, + 147, + 451, + 163 + ], + "spans": [ + { + "bbox": [ + 422, + 147, + 451, + 163 + ], + "type": "image", + "image_path": "97928c55d8cbe9b776bb180a205e23042a648defae7a248d86f12ab8d450c640.jpg" + } + ] + } + ], + "index": 33, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 432, + 165, + 455, + 173 + ], + "lines": [ + { + "bbox": [ + 432, + 165, + 455, + 173 + ], + "spans": [ + { + "bbox": [ + 432, + 165, + 455, + 173 + ], + "type": "text", + "content": "window" + } + ] + } + ], + "index": 34, + "angle": 0, + "type": "image_caption" + } + ], + "index": 33 + }, + { + "type": "image", + "bbox": [ + 120, + 212, + 260, + 295 + ], + "blocks": [ + { + "bbox": [ + 46, + 178, + 547, + 201 + ], + "lines": [ + { + "bbox": [ + 46, + 178, + 547, + 201 + ], + "spans": [ + { + "bbox": [ + 46, + 178, + 547, + 201 + ], + "type": "text", + "content": "Figure 5: Comparison on open-vocabulary semantic segmentation. We evaluate on the same image as in OpenSeg [12]. Notice that MasQCLIP successfully recognizes the windows on the house, demonstrating that MasQCLIP is able to classify small objects." + } + ] + } + ], + "index": 35, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 120, + 212, + 260, + 295 + ], + "lines": [ + { + "bbox": [ + 120, + 212, + 260, + 295 + ], + "spans": [ + { + "bbox": [ + 120, + 212, + 260, + 295 + ], + "type": "image", + "image_path": "b7307c8780ef94a70b5d463f3e2f98eb823853f7020cfd1845f69a477d00bc82.jpg" + } + ] + } + ], + "index": 36, + "angle": 0, + "type": "image_body" + } + ], + "index": 36 + }, + { + "type": "image", + "bbox": [ + 120, + 296, + 258, + 378 + ], + "blocks": [ + { + "bbox": [ + 120, + 296, + 258, + 378 + ], + "lines": [ + { + "bbox": [ + 120, + 296, + 258, + 378 + ], + "spans": [ + { + "bbox": [ + 120, + 296, + 258, + 378 + ], + "type": "image", + "image_path": "9e906a0338cc8efe347b91a36e14765fe17f0f1ec960b13b55f13c21b44e47ae.jpg" + } + ] + } + ], + "index": 37, + "angle": 0, + "type": "image_body" + } + ], + "index": 37 + }, + { + "type": "image", + "bbox": [ + 120, + 379, + 258, + 461 + ], + "blocks": [ + { + "bbox": [ + 120, + 379, + 258, + 461 + ], + "lines": [ + { + "bbox": [ + 120, + 379, + 258, + 461 + ], + "spans": [ + { + "bbox": [ + 120, + 379, + 258, + 461 + ], + "type": "image", + "image_path": "ffa5867664025190cee55d6cffde3d2da2df1f17a30f53280ab23a538d2a0180.jpg" + } + ] + } + ], + "index": 38, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 469, + 546, + 503 + ], + "lines": [ + { + "bbox": [ + 46, + 469, + 546, + 503 + ], + "spans": [ + { + "bbox": [ + 46, + 469, + 546, + 503 + ], + "type": "text", + "content": "Figure 6: Comparison on open-vocabulary panoptic segmentation. We evaluate on the same set of images as in MaskCLIP [9]. The images are from ADE20k dataset. Visualization shows that MasQCLIP produces higher-quality masks and has higher classification accuracy." + } + ] + } + ], + "index": 45, + "angle": 0, + "type": "image_caption" + } + ], + "index": 38 + }, + { + "type": "image", + "bbox": [ + 260, + 213, + 363, + 295 + ], + "blocks": [ + { + "bbox": [ + 260, + 213, + 363, + 295 + ], + "lines": [ + { + "bbox": [ + 260, + 213, + 363, + 295 + ], + "spans": [ + { + "bbox": [ + 260, + 213, + 363, + 295 + ], + "type": "image", + "image_path": "a6f63e171f507d10239d612c33d0af68ef693e49a6b25c2756a25f53341fd716.jpg" + } + ] + } + ], + "index": 39, + "angle": 0, + "type": "image_body" + } + ], + "index": 39 + }, + { + "type": "image", + "bbox": [ + 261, + 296, + 363, + 378 + ], + "blocks": [ + { + "bbox": [ + 261, + 296, + 363, + 378 + ], + "lines": [ + { + "bbox": [ + 261, + 296, + 363, + 378 + ], + "spans": [ + { + "bbox": [ + 261, + 296, + 363, + 378 + ], + "type": "image", + "image_path": "0227ced23a31af289f392e852ec6a923c8f1c0cefb42f78262fced6834a68dfd.jpg" + } + ] + } + ], + "index": 40, + "angle": 0, + "type": "image_body" + } + ], + "index": 40 + }, + { + "type": "image", + "bbox": [ + 261, + 379, + 363, + 461 + ], + "blocks": [ + { + "bbox": [ + 261, + 379, + 363, + 461 + ], + "lines": [ + { + "bbox": [ + 261, + 379, + 363, + 461 + ], + "spans": [ + { + "bbox": [ + 261, + 379, + 363, + 461 + ], + "type": "image", + "image_path": "8a47267291f7bd91033207411f1ac4af2377f3ca3ea25165ed7c34e704ca6267.jpg" + } + ] + } + ], + "index": 41, + "angle": 0, + "type": "image_body" + } + ], + "index": 41 + }, + { + "type": "image", + "bbox": [ + 365, + 213, + 475, + 295 + ], + "blocks": [ + { + "bbox": [ + 365, + 213, + 475, + 295 + ], + "lines": [ + { + "bbox": [ + 365, + 213, + 475, + 295 + ], + "spans": [ + { + "bbox": [ + 365, + 213, + 475, + 295 + ], + "type": "image", + "image_path": "8e52a2530dd8eb1afbd2cecb51224354601da450001b90d343da26bbe5347c39.jpg" + } + ] + } + ], + "index": 42, + "angle": 0, + "type": "image_body" + } + ], + "index": 42 + }, + { + "type": "image", + "bbox": [ + 365, + 296, + 475, + 378 + ], + "blocks": [ + { + "bbox": [ + 365, + 296, + 475, + 378 + ], + "lines": [ + { + "bbox": [ + 365, + 296, + 475, + 378 + ], + "spans": [ + { + "bbox": [ + 365, + 296, + 475, + 378 + ], + "type": "image", + "image_path": "a8ff2ddb5dbce34e240090c2876274c780440a8d6069df6d3f172d213c6bbcb4.jpg" + } + ] + } + ], + "index": 43, + "angle": 0, + "type": "image_body" + } + ], + "index": 43 + }, + { + "type": "image", + "bbox": [ + 365, + 379, + 474, + 461 + ], + "blocks": [ + { + "bbox": [ + 365, + 379, + 474, + 461 + ], + "lines": [ + { + "bbox": [ + 365, + 379, + 474, + 461 + ], + "spans": [ + { + "bbox": [ + 365, + 379, + 474, + 461 + ], + "type": "image", + "image_path": "c222dbd78a250ae4ab504af02fa7aaa676cff9c4d67813d2a1da150e1e64526b.jpg" + } + ] + } + ], + "index": 44, + "angle": 0, + "type": "image_body" + } + ], + "index": 44 + }, + { + "bbox": [ + 66, + 517, + 287, + 541 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 517, + 287, + 541 + ], + "spans": [ + { + "bbox": [ + 66, + 517, + 287, + 541 + ], + "type": "text", + "content": "Class Tokens " + }, + { + "bbox": [ + 66, + 517, + 287, + 541 + ], + "type": "inline_equation", + "content": "(f_{Q}^{\\prime}, f_{K}^{\\prime}" + }, + { + "bbox": [ + 66, + 517, + 287, + 541 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 66, + 517, + 287, + 541 + ], + "type": "inline_equation", + "content": "f_{V}^{\\prime}" + }, + { + "bbox": [ + 66, + 517, + 287, + 541 + ], + "type": "text", + "content": "), are learnable during fine-tuning." + } + ] + } + ], + "index": 46 + }, + { + "bbox": [ + 58, + 544, + 287, + 593 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 544, + 287, + 593 + ], + "spans": [ + { + "bbox": [ + 58, + 544, + 287, + 593 + ], + "type": "text", + "content": "- Tune-CLIP: A new set of CLIP parameters is learned during fine-tuning, and masked-cross attention is performed between Mask Class Tokens and CLIP tokens. We use CLIP parameters as initialization." + } + ] + } + ], + "index": 47 + }, + { + "bbox": [ + 46, + 602, + 287, + 674 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 602, + 287, + 674 + ], + "spans": [ + { + "bbox": [ + 46, + 602, + 287, + 674 + ], + "type": "text", + "content": "In this ablation study, we test the models on semantic and panoptic segmentation under cross-dataset setting. We use the same class-agnostic mask proposal network for all models, and then fine-tune the mask classification module based on the predicted masks. Training settings are all kept the same. Our results are shown in Tab. 5." + } + ] + } + ], + "index": 48 + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": "Adaptation. We compare the evaluation metrics of the above methods on COCO dataset to show the strong adaptation ability of MasQ-Tuning. Compared to Freeze with 19.4" + } + ] + } + ], + "index": 49 + }, + { + "bbox": [ + 304, + 517, + 547, + 649 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 517, + 547, + 649 + ], + "spans": [ + { + "bbox": [ + 304, + 517, + 547, + 649 + ], + "type": "inline_equation", + "content": "PQ" + }, + { + "bbox": [ + 304, + 517, + 547, + 649 + ], + "type": "text", + "content": " and 22.1 mIoU on COCO, Tune-Q has a significant improvement of 29.1 " + }, + { + "bbox": [ + 304, + 517, + 547, + 649 + ], + "type": "inline_equation", + "content": "PQ" + }, + { + "bbox": [ + 304, + 517, + 547, + 649 + ], + "type": "text", + "content": " (from 19.4 to 48.5) and 39.9 mIoU (from 22.1 to 62.0) respectively. This shows that the improvement on adaptation ability should be credited to those learnable query projections " + }, + { + "bbox": [ + 304, + 517, + 547, + 649 + ], + "type": "inline_equation", + "content": "f_{Q}^{\\prime}" + }, + { + "bbox": [ + 304, + 517, + 547, + 649 + ], + "type": "text", + "content": " for Mask Class Tokens. In addition, compared to Tune-CLIP with 49.0 " + }, + { + "bbox": [ + 304, + 517, + 547, + 649 + ], + "type": "inline_equation", + "content": "PQ" + }, + { + "bbox": [ + 304, + 517, + 547, + 649 + ], + "type": "text", + "content": " and 63.6 mIoU on COCO, Tune-Q has much fewer learnable parameters, but only has little performance drop (-0.5 " + }, + { + "bbox": [ + 304, + 517, + 547, + 649 + ], + "type": "inline_equation", + "content": "PQ" + }, + { + "bbox": [ + 304, + 517, + 547, + 649 + ], + "type": "text", + "content": " and -1.6 mIoU). This indicates that simply adding more parameters is not helpful, and our proposed MasQ-Tuning has achieved impressive adaptation ability." + } + ] + } + ], + "index": 50 + }, + { + "bbox": [ + 304, + 653, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 547, + 715 + ], + "type": "text", + "content": "Generalization. We now focus on the performance of the above methods on ADE20k dataset to show the strong generalization ability of MasQ-Tuning. When adding learnable value projections " + }, + { + "bbox": [ + 304, + 653, + 547, + 715 + ], + "type": "inline_equation", + "content": "f_V'" + }, + { + "bbox": [ + 304, + 653, + 547, + 715 + ], + "type": "text", + "content": " for Mask Class Tokens, the model cannot generalize well to ADE20k dataset. Compared to" + } + ] + } + ], + "index": 51 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 297, + 748, + 313, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 748, + 313, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 748, + 313, + 757 + ], + "type": "text", + "content": "894" + } + ] + } + ], + "index": 52 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 118, + 70, + 251, + 147 + ], + "blocks": [ + { + "bbox": [ + 118, + 70, + 251, + 147 + ], + "lines": [ + { + "bbox": [ + 118, + 70, + 251, + 147 + ], + "spans": [ + { + "bbox": [ + 118, + 70, + 251, + 147 + ], + "type": "image", + "image_path": "5fa77b82f5b728cdfc8c9d9dc1ad6ee25ef98f5cd221d30d859a7f1c47c1c0e2.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 117, + 148, + 252, + 224 + ], + "blocks": [ + { + "bbox": [ + 117, + 148, + 252, + 224 + ], + "lines": [ + { + "bbox": [ + 117, + 148, + 252, + 224 + ], + "spans": [ + { + "bbox": [ + 117, + 148, + 252, + 224 + ], + "type": "image", + "image_path": "180b1eefdf780a8db901004209e282444b0d65137219005fedfedd22caca7c57.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 132, + 228, + 236, + 238 + ], + "lines": [ + { + "bbox": [ + 132, + 228, + 236, + 238 + ], + "spans": [ + { + "bbox": [ + 132, + 228, + 236, + 238 + ], + "type": "text", + "content": "(a) \"a black cat\", \"an orange cat\"" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 255, + 70, + 356, + 148 + ], + "blocks": [ + { + "bbox": [ + 255, + 70, + 356, + 148 + ], + "lines": [ + { + "bbox": [ + 255, + 70, + 356, + 148 + ], + "spans": [ + { + "bbox": [ + 255, + 70, + 356, + 148 + ], + "type": "image", + "image_path": "e8b4b26ec7b8039f10ff1713e81154076fc8ba049fc4afef8f79f78d39a0a462.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 255, + 148, + 356, + 224 + ], + "blocks": [ + { + "bbox": [ + 255, + 148, + 356, + 224 + ], + "lines": [ + { + "bbox": [ + 255, + 148, + 356, + 224 + ], + "spans": [ + { + "bbox": [ + 255, + 148, + 356, + 224 + ], + "type": "image", + "image_path": "f06f9eb282f5a372a7680567b9af3f746863c1168ac85846a392a6a0ad5fa12f.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 279, + 228, + 339, + 238 + ], + "lines": [ + { + "bbox": [ + 279, + 228, + 339, + 238 + ], + "spans": [ + { + "bbox": [ + 279, + 228, + 339, + 238 + ], + "type": "text", + "content": "(b) \"beer\", \"wine\"" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 243, + 547, + 266 + ], + "lines": [ + { + "bbox": [ + 46, + 243, + 547, + 266 + ], + "spans": [ + { + "bbox": [ + 46, + 243, + 547, + 266 + ], + "type": "text", + "content": "Figure 7: User-specified segmentation. We use the model trained on COCO-panoptic for evaluation. Visualization results show that our model can distinguish subtle differences among objects." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 360, + 70, + 474, + 148 + ], + "blocks": [ + { + "bbox": [ + 360, + 70, + 474, + 148 + ], + "lines": [ + { + "bbox": [ + 360, + 70, + 474, + 148 + ], + "spans": [ + { + "bbox": [ + 360, + 70, + 474, + 148 + ], + "type": "image", + "image_path": "07a0426558e65ae0c540d3e5498ca62d395a5db31f364e99cb6f56e5db4574e5.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 360, + 148, + 474, + 224 + ], + "blocks": [ + { + "bbox": [ + 360, + 148, + 474, + 224 + ], + "lines": [ + { + "bbox": [ + 360, + 148, + 474, + 224 + ], + "spans": [ + { + "bbox": [ + 360, + 148, + 474, + 224 + ], + "type": "image", + "image_path": "9b6e5755d00e48243b8ad56079806a8689750bb777bb6573a2f37fd5e91d92b2.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 382, + 228, + 458, + 238 + ], + "lines": [ + { + "bbox": [ + 382, + 228, + 458, + 238 + ], + "spans": [ + { + "bbox": [ + 382, + 228, + 458, + 238 + ], + "type": "text", + "content": "(c) \"an adult\", \"a child\"" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 285, + 287, + 405 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 285, + 287, + 405 + ], + "spans": [ + { + "bbox": [ + 46, + 285, + 287, + 405 + ], + "type": "text", + "content": "Tune-Q with 23.3 PQ, Tune-V, Tune-QKV and Tune-CLIP have a performance drop of 8.9, 8.4, and 8.6 on " + }, + { + "bbox": [ + 46, + 285, + 287, + 405 + ], + "type": "inline_equation", + "content": "PQ" + }, + { + "bbox": [ + 46, + 285, + 287, + 405 + ], + "type": "text", + "content": " respectively. This proves the importance of freezing " + }, + { + "bbox": [ + 46, + 285, + 287, + 405 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{img}}" + }, + { + "bbox": [ + 46, + 285, + 287, + 405 + ], + "type": "text", + "content": " which is interpreted as dense CLIP features. By inheriting " + }, + { + "bbox": [ + 46, + 285, + 287, + 405 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{img}}" + }, + { + "bbox": [ + 46, + 285, + 287, + 405 + ], + "type": "text", + "content": " from the CLIP model, MasQCLIP is able to preserve the original feature space within CLIP. Compared to Tune-QK, Tune-Q reaches better performance on ADE20k and is more parameter-efficient, where only " + }, + { + "bbox": [ + 46, + 285, + 287, + 405 + ], + "type": "inline_equation", + "content": "8.2\\%" + }, + { + "bbox": [ + 46, + 285, + 287, + 405 + ], + "type": "text", + "content": " of original parameters in CLIP visual encoder are added for training. Therefore, we choose Tune-Q as the fine-tuning strategy of MasQCLIP." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 418, + 159, + 431 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 418, + 159, + 431 + ], + "spans": [ + { + "bbox": [ + 47, + 418, + 159, + 431 + ], + "type": "text", + "content": "5.5. Qualitative Results" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 439, + 287, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 439, + 287, + 594 + ], + "spans": [ + { + "bbox": [ + 46, + 439, + 287, + 594 + ], + "type": "text", + "content": "In this section, we compare the visualization results of MasQCLIP with previous models [9, 12]. The results of instance, semantic, and panoptic segmentation are presented in Fig. 4, Fig. 5, and Fig. 6 respectively. For a fair comparison, We all use the same set of images as previous works [9, 12]. We observe from the visualization results that MasQCLIP produces more robust mask proposals and enjoys a higher mask classification accuracy, which corresponds to our two key components proposed in MasQCLIP. As shown in Fig. 7, MasQCLIP exhibits the ability to segment objects of arbitrary classes as per user specifications and to discriminate between subtle distinctions within them (e.g. \"beer\" vs. \"wine\", \"child\" vs. \"adult\")." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 47, + 609, + 116, + 622 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 609, + 116, + 622 + ], + "spans": [ + { + "bbox": [ + 47, + 609, + 116, + 622 + ], + "type": "text", + "content": "5.6. Efficiency" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 629, + 287, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 287, + 712 + ], + "type": "text", + "content": "MasQCLIP exhibits great capability in open-vocabulary universal segmentation while being computationally efficient at the same time. We report the results of GFLOPs in Tab. 6. As shown, the GFLOPs of MasQCLIP is only " + }, + { + "bbox": [ + 46, + 629, + 287, + 712 + ], + "type": "inline_equation", + "content": "14.5\\%" + }, + { + "bbox": [ + 46, + 629, + 287, + 712 + ], + "type": "text", + "content": " higher than the combined GFLOPs of Mask2Former and CLIP visual encoder, and is " + }, + { + "bbox": [ + 46, + 629, + 287, + 712 + ], + "type": "inline_equation", + "content": "34.1\\%" + }, + { + "bbox": [ + 46, + 629, + 287, + 712 + ], + "type": "text", + "content": " lower than the GFLOPs of MaskCLIP." + } + ] + } + ], + "index": 14 + }, + { + "type": "table", + "bbox": [ + 348, + 282, + 502, + 340 + ], + "blocks": [ + { + "bbox": [ + 348, + 282, + 502, + 340 + ], + "lines": [ + { + "bbox": [ + 348, + 282, + 502, + 340 + ], + "spans": [ + { + "bbox": [ + 348, + 282, + 502, + 340 + ], + "type": "table", + "html": "
ModelsGFLOPs
Mask2Former [7]78.9
CLIP Visual Encoder [31]233.0
MaskCLIP† [9]542.0
MasQCLIP (ours)357.2
", + "image_path": "7291a5a25faf002548be67ee98b96014c6aac1daf74059c0c726af45abb7595b.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "table_body" + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 344, + 547, + 389 + ], + "lines": [ + { + "bbox": [ + 305, + 344, + 547, + 389 + ], + "spans": [ + { + "bbox": [ + 305, + 344, + 547, + 389 + ], + "type": "text", + "content": "Table 6: Model efficiency. The resolution of input images is set to " + }, + { + "bbox": [ + 305, + 344, + 547, + 389 + ], + "type": "inline_equation", + "content": "640 \\times 640" + }, + { + "bbox": [ + 305, + 344, + 547, + 389 + ], + "type": "text", + "content": " for Mask2Former and " + }, + { + "bbox": [ + 305, + 344, + 547, + 389 + ], + "type": "inline_equation", + "content": "336 \\times 336" + }, + { + "bbox": [ + 305, + 344, + 547, + 389 + ], + "type": "text", + "content": " for CLIP Visual Encoder. We use the CLIP model ViT-L/14@336px. " + }, + { + "bbox": [ + 305, + 344, + 547, + 389 + ], + "type": "inline_equation", + "content": "\\dagger" + }, + { + "bbox": [ + 305, + 344, + 547, + 389 + ], + "type": "text", + "content": " means our re-implement according to the paper (no public codes available)." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 403, + 383, + 416 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 403, + 383, + 416 + ], + "spans": [ + { + "bbox": [ + 306, + 403, + 383, + 416 + ], + "type": "text", + "content": "6. Conclusions" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 424, + 545, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 424, + 545, + 544 + ], + "spans": [ + { + "bbox": [ + 304, + 424, + 545, + 544 + ], + "type": "text", + "content": "We propose a two-stage model, MasQCLIP, for open-vocabulary universal segmentation. We first design a progressive distillation process for the class-agnostic mask proposal network to segment open-world masks. Additionally, we adapt CLIP models for mask (region) classification while maintaining the generalization ability of CLIP through our proposed MasQ-Tuning method. We achieve state-of-the-art results with substantial improvement over the existing approaches across three open-vocabulary tasks including instance, semantic, and panoptic segmentation." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 547, + 545, + 632 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 547, + 545, + 632 + ], + "spans": [ + { + "bbox": [ + 304, + 547, + 545, + 632 + ], + "type": "text", + "content": "Limitations. Since MasQCLIP is built on top of a pretrained CLIP model, though fine-tuning is introduced, the performance of our model is nevertheless largely decided by the generalization ability of the CLIP model. Another limitation of our method is that mask proposals are generated by a fixed network (once pre-trained), which might limit its capability for object types of arbitrary specification." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 634, + 545, + 657 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 634, + 545, + 657 + ], + "spans": [ + { + "bbox": [ + 306, + 634, + 545, + 657 + ], + "type": "text", + "content": "Acknowledgement. This work is supported by NSF Award IIS-2127544." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 306, + 670, + 365, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 670, + 365, + 682 + ], + "spans": [ + { + "bbox": [ + 306, + 670, + 365, + 682 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 310, + 691, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 691, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 310, + 691, + 545, + 713 + ], + "type": "text", + "content": "[1] Ankan Bansal, Karan Sikka, Gaurav Sharma, Rama Chellappa, and Ajay Divakaran. Zero-shot object detection. In" + } + ] + } + ], + "index": 22 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "text", + "content": "895" + } + ] + } + ], + "index": 23 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 73, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 67, + 73, + 286, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 73, + 286, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 73, + 286, + 95 + ], + "type": "text", + "content": "Proceedings of the European Conference on Computer Vision, pages 384-400, 2018. 5, 6" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 53, + 96, + 287, + 151 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 96, + 287, + 151 + ], + "spans": [ + { + "bbox": [ + 53, + 96, + 287, + 151 + ], + "type": "text", + "content": "[2] David Biertimpel, Sindi Shkodrani, Anil S Baslamisli, and Nóra Baka. Prior to segment: Foreground cues for weakly annotated classes in partially supervised instance segmentation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2824-2833, 2021. 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 152, + 288, + 185 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 152, + 288, + 185 + ], + "spans": [ + { + "bbox": [ + 53, + 152, + 288, + 185 + ], + "type": "text", + "content": "[3] Maxime Bucher, Tuan-Hung Vu, Matthieu Cord, and Patrick Pérez. Zero-shot semantic segmentation. Advances in Neural Information Processing Systems, 32, 2019. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 186, + 288, + 229 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 186, + 288, + 229 + ], + "spans": [ + { + "bbox": [ + 53, + 186, + 288, + 229 + ], + "type": "text", + "content": "[4] Han Cai, Chuang Gan, Ligeng Zhu, and Song Han. Tinytl: Reduce memory, not parameters for efficient on-device learning. Advances in Neural Information Processing Systems, 33:11285-11297, 2020. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 232, + 288, + 275 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 232, + 288, + 275 + ], + "spans": [ + { + "bbox": [ + 53, + 232, + 288, + 275 + ], + "type": "text", + "content": "[5] Zhaowei Cai, Gukyeong Kwon, Avinash Ravichandran, Erhan Bas, Zhuowen Tu, Rahul Bhotika, and Stefano Soatto. X-detr: A versatile architecture for instance-wise vision-language tasks. arXiv preprint arXiv:2204.05626, 2022. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 277, + 287, + 331 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 277, + 287, + 331 + ], + "spans": [ + { + "bbox": [ + 53, + 277, + 287, + 331 + ], + "type": "text", + "content": "[6] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Proceedings of the European Conference on Computer Vision, pages 213-229. Springer, 2020. 1, 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 332, + 288, + 387 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 332, + 288, + 387 + ], + "spans": [ + { + "bbox": [ + 53, + 332, + 288, + 387 + ], + "type": "text", + "content": "[7] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1290–1299, 2022. 1, 2, 5, 9" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 388, + 287, + 431 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 388, + 287, + 431 + ], + "spans": [ + { + "bbox": [ + 53, + 388, + 287, + 431 + ], + "type": "text", + "content": "[8] Bowen Cheng, Alex Schwing, and Alexander Kirillov. Per-pixel classification is not all you need for semantic segmentation. Advances in Neural Information Processing Systems, 34:17864-17875, 2021. 1" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 434, + 287, + 476 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 434, + 287, + 476 + ], + "spans": [ + { + "bbox": [ + 53, + 434, + 287, + 476 + ], + "type": "text", + "content": "[9] Zheng Ding, Jieke Wang, and Zhuowen Tu. Open-vocabulary universal image segmentation with maskclip. In International Conference on Machine Learning, 2023. 1, 2, 3, 4, 5, 6, 7, 8, 9" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 478, + 287, + 544 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 478, + 287, + 544 + ], + "spans": [ + { + "bbox": [ + 48, + 478, + 287, + 544 + ], + "type": "text", + "content": "[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2020. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 545, + 287, + 599 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 545, + 287, + 599 + ], + "spans": [ + { + "bbox": [ + 48, + 545, + 287, + 599 + ], + "type": "text", + "content": "[11] Mark Everingham, SM Eslami, Luc Van Gool, Christopher KI Williams, John Winn, and Andrew Zisserman. The Pascal visual object classes challenge: A retrospective. International Journal of Computer Vision, 111(1):98-136, 2015. 5" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 601, + 287, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 601, + 287, + 645 + ], + "spans": [ + { + "bbox": [ + 48, + 601, + 287, + 645 + ], + "type": "text", + "content": "[12] Golnaz Ghiasi, Xiuye Gu, Yin Cui, and Tsung-Yi Lin. Scaling open-vocabulary image segmentation with image-level labels. In Proceedings of the European Conference on Computer Vision, pages 540-557. Springer, 2022. 2, 6, 8, 9" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 647, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 287, + 689 + ], + "type": "text", + "content": "[13] Xiuye Gu, Tsung-Yi Lin, Weicheng Kuo, and Yin Cui. Open-vocabulary object detection via vision and language knowledge distillation. In International Conference on Learning Representations, 2022. 1, 2, 5" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "text", + "content": "[14] Kaiming He, Georgia Gkioxari, Piotr Dólar, and Ross Girshick. Mask r-cnn. In Proceedings of the IEEE International" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 94 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 94 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 94 + ], + "type": "text", + "content": "Conference on Computer Vision, pages 2961-2969, 2017. 2, 5" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 95, + 545, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 95, + 545, + 139 + ], + "spans": [ + { + "bbox": [ + 308, + 95, + 545, + 139 + ], + "type": "text", + "content": "[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 140, + 545, + 182 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 140, + 545, + 182 + ], + "spans": [ + { + "bbox": [ + 308, + 140, + 545, + 182 + ], + "type": "text", + "content": "[16] Xuehai He, Chunyuan Li, Pengchuan Zhang, Jianwei Yang, and Xin Eric Wang. Parameter-efficient fine-tuning for vision transformers. arXiv preprint arXiv:2203.16329, 2022. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 184, + 545, + 216 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 184, + 545, + 216 + ], + "spans": [ + { + "bbox": [ + 308, + 184, + 545, + 216 + ], + "type": "text", + "content": "[17] Geoffrey Hinton, Oriol Vinyals, Jeff Dean, et al. Distilling the knowledge in a neural network. arXiv preprint arXiv:1503.02531, 2015. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 217, + 545, + 271 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 217, + 545, + 271 + ], + "spans": [ + { + "bbox": [ + 308, + 217, + 545, + 271 + ], + "type": "text", + "content": "[18] Dat Huynh, Jason Kuen, Zhe Lin, Jiumiang Gu, and Ehsan Elhamifar. Open-vocabulary instance segmentation via robust cross-modal pseudo-labeling. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7020-7031, 2022. 2, 5, 6" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 273, + 545, + 326 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 273, + 545, + 326 + ], + "spans": [ + { + "bbox": [ + 308, + 273, + 545, + 326 + ], + "type": "text", + "content": "[19] Jaedong Hwang, Seoung Wug Oh, Joon-Young Lee, and Bohyung Han. Exemplar-based open-set panoptic segmentation network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1175–1184, 2021. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 327, + 545, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 327, + 545, + 392 + ], + "spans": [ + { + "bbox": [ + 308, + 327, + 545, + 392 + ], + "type": "text", + "content": "[20] Chao Jia, Yinfei Yang, Ye Xia, Yi-Ting Chen, Zarana Parekh, Hieu Pham, Quoc Le, Yun-Hsuan Sung, Zhen Li, and Tom Duerig. Scaling up visual and vision-language representation learning with noisy text supervision. In International Conference on Machine Learning, pages 4904-4916, 2021. 2, 6" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 393, + 545, + 446 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 393, + 545, + 446 + ], + "spans": [ + { + "bbox": [ + 308, + 393, + 545, + 446 + ], + "type": "text", + "content": "[21] Menglin Jia, Luming Tang, Bor-Chun Chen, Claire Cardie, Serge Belongie, Bharath Hariharan, and Ser-Nam Lim. Visual prompt tuning. In Proceedings of the European Conference on Computer Vision, pages 709-727. Springer, 2022. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 449, + 545, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 449, + 545, + 491 + ], + "spans": [ + { + "bbox": [ + 308, + 449, + 545, + 491 + ], + "type": "text", + "content": "[22] Alexander Kirillov, Kaiming He, Ross Girshick, Carsten Rother, and Piotr Dollar. Panoptic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9404-9413, 2019. 2, 5" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 493, + 545, + 535 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 493, + 545, + 535 + ], + "spans": [ + { + "bbox": [ + 308, + 493, + 545, + 535 + ], + "type": "text", + "content": "[23] Boyi Li, Kilian Q Weinberger, Serge Belongie, Vladlen Koltun, and René Ranftl. Language-driven semantic segmentation. In International Conference on Learning Representations, 2022. 2, 6" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 537, + 545, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 537, + 545, + 602 + ], + "spans": [ + { + "bbox": [ + 308, + 537, + 545, + 602 + ], + "type": "text", + "content": "[24] Liunian Harold Li, Pengchuan Zhang, Haotian Zhang, Jianwei Yang, Chunyuan Li, Yiwu Zhong, Lijuan Wang, Lu Yuan, Lei Zhang, Jenq-Neng Hwang, et al. Grounded language-image pre-training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10965-10975, 2022. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 604, + 545, + 658 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 604, + 545, + 658 + ], + "spans": [ + { + "bbox": [ + 308, + 604, + 545, + 658 + ], + "type": "text", + "content": "[25] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In Proceedings of the European Conference on Computer Vision, pages 740-755. Springer, 2014. 3, 5" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 658, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 658, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 658, + 545, + 689 + ], + "type": "text", + "content": "[26] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In International Conference on Learning Representations, 2018. 5" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "text", + "content": "[27] Huaishao Luo, Lei Ji, Ming Zhong, Yang Chen, Wen Lei, Nan Duan, and Tianrui Li. Clip4clip: An empirical study" + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 298, + 749, + 313, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 749, + 313, + 757 + ], + "spans": [ + { + "bbox": [ + 298, + 749, + 313, + 757 + ], + "type": "text", + "content": "896" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 712 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "text", + "content": "of clip for end to end video clip retrieval. arXiv preprint arXiv:2104.08860, 2021. 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 288, + 160 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 288, + 160 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 288, + 160 + ], + "type": "text", + "content": "[28] Luke Melas-Kyriazi, Christian Rupprecht, Iro Laina, and Andrea Vedaldi. Deep spectral methods: A surprisingly strong baseline for unsupervised semantic segmentation and localization. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8364-8375, 2022. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 162, + 288, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 162, + 288, + 228 + ], + "spans": [ + { + "bbox": [ + 48, + 162, + 288, + 228 + ], + "type": "text", + "content": "[29] Roozbeh Mottaghi, Xianjie Chen, Xiaobai Liu, Nam-Gyu Cho, Seong-Whan Lee, Sanja Fidler, Raquel Urtasun, and Alan Yuille. The role of context for object detection and semantic segmentation in the wild. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 891–898, 2014. 5" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 228, + 288, + 282 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 228, + 288, + 282 + ], + "spans": [ + { + "bbox": [ + 48, + 228, + 288, + 282 + ], + "type": "text", + "content": "[30] Or Patashnik, Zongze Wu, Eli Shechtman, Daniel Cohen-Or, and Dani Lischinski. Styleclip: Text-driven manipulation of stylegan imagery. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2085–2094, 2021. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 283, + 288, + 348 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 283, + 288, + 348 + ], + "spans": [ + { + "bbox": [ + 48, + 283, + 288, + 348 + ], + "type": "text", + "content": "[31] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning, pages 8748-8763. PMLR, 2021. 1, 9" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 350, + 288, + 415 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 350, + 288, + 415 + ], + "spans": [ + { + "bbox": [ + 48, + 350, + 288, + 415 + ], + "type": "text", + "content": "[32] Yongming Rao, Wenliang Zhao, Guangyi Chen, Yansong Tang, Zheng Zhu, Guan Huang, Jie Zhou, and Jiwen Lu. Denseclip: Language-guided dense prediction with context-aware prompting. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18082-18091, 2022. 2, 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 415, + 288, + 458 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 415, + 288, + 458 + ], + "spans": [ + { + "bbox": [ + 48, + 415, + 288, + 458 + ], + "type": "text", + "content": "[33] Sylvestre-Alvise Rebuffi, Hakan Bilen, and Andrea Vedaldi. Learning multiple visual domains with residual adapters. Advances in Neural Information Processing Systems, 30, 2017. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 460, + 288, + 514 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 460, + 288, + 514 + ], + "spans": [ + { + "bbox": [ + 48, + 460, + 288, + 514 + ], + "type": "text", + "content": "[34] Mark Sandler, Andrey Zhmoginov, Max Vlademyrov, and Andrew Jackson. Fine-tuning image transformers using learnable memory. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12155-12164, 2022. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 514, + 288, + 568 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 514, + 288, + 568 + ], + "spans": [ + { + "bbox": [ + 48, + 514, + 288, + 568 + ], + "type": "text", + "content": "[35] Sheng Shen, Liunian Harold Li, Hao Tan, Mohit Bansal, Anna Rohrbach, Kai-Wei Chang, Zhewei Yao, and Kurt Keutzer. How much can clip benefit vision-and-language tasks? In International Conference on Learning Representations, 2022. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 570, + 288, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 570, + 288, + 624 + ], + "spans": [ + { + "bbox": [ + 48, + 570, + 288, + 624 + ], + "type": "text", + "content": "[36] Jamie Shotton, John Winn, Carsten Rother, and Antonio Criminisi. Textonboost: Joint appearance, shape and context modeling for multi-class object recognition and segmentation. In Proceedings of the European Conference on Computer Vision, pages 1-15. Springer, 2006. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 625, + 288, + 658 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 625, + 288, + 658 + ], + "spans": [ + { + "bbox": [ + 48, + 625, + 288, + 658 + ], + "type": "text", + "content": "[37] Karen Simonyan and Andrew Zisserman. Very deep convolutional networks for large-scale image recognition. arXiv preprint arXiv:1409.1556, 2014. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 658, + 288, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 658, + 288, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 658, + 288, + 712 + ], + "type": "text", + "content": "[38] Yi-Lin Sung, Jaemin Cho, and Mohit Bansal. VI-adapter: Parameter-efficient transfer learning for vision-and-language tasks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5227-5237, 2022. 3" + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 25, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "text", + "content": "[39] Zhuowen Tu. Auto-context and its application to high-level vision tasks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1-8. IEEE, 2008. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 307, + 118, + 545, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 545, + 162 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 545, + 162 + ], + "type": "text", + "content": "[40] Zhuowen Tu, Xiangrong Chen, Alan L Yuille, and Song-Chun Zhu. Image parsing: Unifying segmentation, detection, and recognition. International Journal of Computer Vision, 63(2):113-140, 2005. 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 163, + 545, + 207 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 163, + 545, + 207 + ], + "spans": [ + { + "bbox": [ + 307, + 163, + 545, + 207 + ], + "type": "text", + "content": "[41] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in Neural Information Processing Systems, 30, 2017. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 209, + 545, + 263 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 209, + 545, + 263 + ], + "spans": [ + { + "bbox": [ + 308, + 209, + 545, + 263 + ], + "type": "text", + "content": "[42] Weiyao Wang, Matt Feiszli, Heng Wang, Jitendra Malik, and Du Tran. Open-world instance segmentation: Exploiting pseudo ground truth from learned pairwise affinity. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4422-4432, 2022. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 265, + 545, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 265, + 545, + 330 + ], + "spans": [ + { + "bbox": [ + 308, + 265, + 545, + 330 + ], + "type": "text", + "content": "[43] Xinlong Wang, Zhiding Yu, Shalini De Mello, Jan Kautz, Anima Anandkumar, Chunhua Shen, and Jose M Alvarez. Freesolo: Learning to segment objects without annotations. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14176-14186, 2022. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 332, + 545, + 386 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 332, + 545, + 386 + ], + "spans": [ + { + "bbox": [ + 308, + 332, + 545, + 386 + ], + "type": "text", + "content": "[44] Zhecan Wang, Noel Codella, Yen-Chun Chen, Luowei Zhou, Jianwei Yang, Xiyang Dai, Bin Xiao, Haoxuan You, Shih-Fu Chang, and Lu Yuan. Clip-td: Clip targeted distillation for vision-language tasks. arXiv preprint arXiv:2201.05729, 2022. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 388, + 545, + 443 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 388, + 545, + 443 + ], + "spans": [ + { + "bbox": [ + 308, + 388, + 545, + 443 + ], + "type": "text", + "content": "[45] Yuwen Xiong, Renjie Liao, Hengshuang Zhao, Rui Hu, Min Bai, Ersin Yumer, and Raquel Urtasun. Upsnet: A unified panoptic segmentation network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 445, + 545, + 499 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 445, + 545, + 499 + ], + "spans": [ + { + "bbox": [ + 308, + 445, + 545, + 499 + ], + "type": "text", + "content": "[46] Mengde Xu, Zheng Zhang, Fangyun Wei, Yutong Lin, Yue Cao, Han Hu, and Xiang Bai. A simple baseline for open-vocabulary semantic segmentation with pre-trained vision-language model. In Proceedings of the European Conference on Computer Vision, pages 736-753. Springer, 2022. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 501, + 545, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 501, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 308, + 501, + 545, + 555 + ], + "type": "text", + "content": "[47] Lihe Yang, Wei Zhuo, Lei Qi, Yinghuan Shi, and Yang Gao. St++: Make self-training work better for semi-supervised semantic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4268-4277, 2022. 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 557, + 545, + 612 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 557, + 545, + 612 + ], + "spans": [ + { + "bbox": [ + 308, + 557, + 545, + 612 + ], + "type": "text", + "content": "[48] Jianlong Yuan, Yifan Liu, Chunhua Shen, Zhibin Wang, and Hao Li. A simple baseline for semi-supervised semantic segmentation with strong data augmentation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 8229-8238, 2021. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 613, + 545, + 657 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 613, + 545, + 657 + ], + "spans": [ + { + "bbox": [ + 308, + 613, + 545, + 657 + ], + "type": "text", + "content": "[49] Yuhang Zang, Wei Li, Kaiyang Zhou, Chen Huang, and Chen Change Loy. Open-vocabulary detr with conditional matching. In Proceedings of the European Conference on Computer Vision, pages 106-122, 2022. 2" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 658, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 658, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 658, + 545, + 712 + ], + "type": "text", + "content": "[50] Alireza Zareian, Kevin Dela Rosa, Derek Hao Hu, and Shih-Fu Chang. Open-vocabulary object detection using captions. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14393-14402, 2021. 2, 5, 6" + } + ] + } + ], + "index": 24 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "type": "text", + "content": "897" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 495 + ], + "type": "list", + "angle": 0, + "index": 8, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 127 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 127 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 127 + ], + "type": "text", + "content": "[51] Jeffrey O Zhang, Alexander Sax, Amir Zamir, Leonidas Guibas, and Jitendra Malik. Side-tuning: a baseline for network adaptation via additive side networks. In Proceedings of the European Conference on Computer Vision, pages 698-714. Springer, 2020. 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 129, + 288, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 129, + 288, + 184 + ], + "spans": [ + { + "bbox": [ + 48, + 129, + 288, + 184 + ], + "type": "text", + "content": "[52] Linfeng Zhang, Jiebo Song, Anni Gao, Jingwei Chen, Chenglong Bao, and Kaisheng Ma. Be your own teacher: Improve the performance of convolutional neural networks via self distillation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 3713-3722, 2019. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 185, + 288, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 185, + 288, + 239 + ], + "spans": [ + { + "bbox": [ + 48, + 185, + 288, + 239 + ], + "type": "text", + "content": "[53] Renrui Zhang, Rongyao Fang, Wei Zhang, Peng Gao, Kunchang Li, Jifeng Dai, Yu Qiao, and Hongsheng Li. Tip-adapter: Training-free clip-adapter for better vision-language modeling. arXiv preprint arXiv:2111.03930, 2021. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 240, + 288, + 284 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 240, + 288, + 284 + ], + "spans": [ + { + "bbox": [ + 48, + 240, + 288, + 284 + ], + "type": "text", + "content": "[54] Ye Zheng, Jiahong Wu, Yongqiang Qin, Faen Zhang, and Li Cui. Zero-shot instance segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2593-2602, 2021. 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 285, + 288, + 351 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 285, + 288, + 351 + ], + "spans": [ + { + "bbox": [ + 48, + 285, + 288, + 351 + ], + "type": "text", + "content": "[55] Yiwu Zhong, Jianwei Yang, Pengchuan Zhang, Chunyuan Li, Noel Codella, Liunian Harold Li, Luowei Zhou, Xiyang Dai, Lu Yuan, Yin Li, and Jianfeng Gao. Regionclip: Region-based language-image pretraining. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 16793-16803, 2022. 1, 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 352, + 288, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 352, + 288, + 407 + ], + "spans": [ + { + "bbox": [ + 48, + 352, + 288, + 407 + ], + "type": "text", + "content": "[56] Bolei Zhou, Hang Zhao, Xavier Puig, Sanja Fidler, Adela Barriuso, and Antonio Torralba. Scene parsing through ade20k dataset. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 633-641, 2017. 5" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 407, + 288, + 452 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 407, + 288, + 452 + ], + "spans": [ + { + "bbox": [ + 48, + 407, + 288, + 452 + ], + "type": "text", + "content": "[57] Bolei Zhou, Hang Zhao, Xavier Puig, Tete Xiao, Sanja Fidler, Adela Barriuso, and Antonio Torralba. Semantic understanding of scenes through the ade20k dataset. International Journal of Computer Vision, 127(3):302-321, 2019. 5" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 453, + 288, + 495 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 453, + 288, + 495 + ], + "spans": [ + { + "bbox": [ + 48, + 453, + 288, + 495 + ], + "type": "text", + "content": "[58] Chong Zhou, Chen Change Loy, and Bo Dai. Extract free dense labels from clip. In Proceedings of the European Conference on Computer Vision, pages 696-712. Springer, 2022. 2" + } + ] + } + ], + "index": 7 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "type": "text", + "content": "898" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 11 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/6e476140-cab6-422d-9817-a489e1ead454_content_list.json b/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/6e476140-cab6-422d-9817-a489e1ead454_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..026ed423b117272fbe84f52b1bfd99f1e76c4c68 --- /dev/null +++ b/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/6e476140-cab6-422d-9817-a489e1ead454_content_list.json @@ -0,0 +1,1621 @@ +[ + { + "type": "text", + "text": "MasaCtrl: Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing", + "text_level": 1, + "bbox": [ + 135, + 128, + 833, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Mingdeng Cao $^{1,2*}$ Xintao Wang $^{2}$ Zhongang Qi $^{2}$ Ying Shan $^{2}$ Xiaohu Qie $^{2}$ Yinqiang Zheng $^{1}$ $^{1}$ The University of Tokyo ${}^{2}$ ARC Lab, Tencent PCG \nhttps://github.com/TencentARC/MasaCtrl", + "bbox": [ + 86, + 210, + 906, + 281 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/99d6a69dc4cce4ee20c38447e1f616a3bde67f89ed8cae7bc7e8bccf40826b33.jpg", + "image_caption": [ + "Input real image" + ], + "image_footnote": [], + "bbox": [ + 78, + 292, + 336, + 393 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/36a1938290766f5b3cc7ea1bbf3369d82ba8a349d1c9022b195e9fae4e93f8d7.jpg", + "image_caption": [ + "\"A sitting boy\" $\\rightarrow$ \"... standing ...\"" + ], + "image_footnote": [], + "bbox": [ + 339, + 292, + 596, + 393 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/d6d8ade6f4570e9c392ff6822ca08cb9188645dd98dcf844b17bed52e4908a38.jpg", + "image_caption": [ + "Input real image \"... , giving a thumbs up\"" + ], + "image_footnote": [], + "bbox": [ + 599, + 292, + 861, + 393 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/a2fb0f168cdc05bfd60ace390b4f882da4197c7f4ff0b4aae1c809b93cb40cab.jpg", + "image_caption": [ + "\"Elon Musk\" $\\rightarrow$ \"... side view ...\"" + ], + "image_footnote": [], + "bbox": [ + 78, + 412, + 336, + 513 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/df3b1a6b61a933b60d12f663e1aaf6d7784cb31df63436cc4915ab98b846ac7e.jpg", + "image_caption": [ + "\"An apple\" $\\rightarrow$ \"Two apples\"" + ], + "image_footnote": [], + "bbox": [ + 339, + 412, + 596, + 513 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/86d0cf2101bc73836e0dcc7cfb727fb0b04ff029e212fe1d32a22103e3901dc0.jpg", + "image_caption": [ + "\"A standing bird\" $\\rightarrow$ \"..., spreading wings\"", + "Figure 1: Our method MasaCtrl can perform text-based non-rigid image synthesis and real image editing without fine-tuning. Meanwhile, our method can be easily integrated into controllable diffusion models, like T2I-Adapter [17] or ControlNet [45], to perform more consistent and faithful synthesis and editing (last column)." + ], + "image_footnote": [], + "bbox": [ + 599, + 412, + 861, + 513 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 598, + 313, + 614 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Despite the success in large-scale text-to-image generation and text-conditioned image editing, existing methods still struggle to produce consistent generation and editing results. For example, generation approaches usually fail to synthesize multiple images of the same objects/characters but with different views or poses. Meanwhile, existing editing methods either fail to achieve effective complex non-rigid editing while maintaining the overall textures and identity, or require time-consuming fine-tuning to capture the image-specific appearance. In this paper, we develop MasaCtrl, a tuning-free method to achieve consistent image generation and complex non-rigid image editing simultaneously. Specifically, MasaCtrl converts existing self-attention in diffusion models into mutual self-attention, so that it can query correlated local contents and textures from source images for consistency. To further alleviate the query", + "bbox": [ + 75, + 631, + 472, + 875 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "confusion between foreground and background, we propose a mask-guided mutual self-attention strategy, where the mask can be easily extracted from the cross-attention maps. Extensive experiments show that the proposed MasaCtrl can produce impressive results in both consistent image generation and complex non-rigid real image editing.", + "bbox": [ + 496, + 599, + 892, + 691 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 500, + 736, + 632, + 752 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Recent advances in text-to-image (T2I) generation [25, 19, 41, 24, 27] have achieved great success. Those large-scale T2I models, such as Stable Diffusion [27], can generate diverse and high-quality images conforming to given text prompts. When leveraging the T2I models, we can also perform promising text-conditioned image editing [19, 10, 35, 21]. However, there is still a large gap between our needs and existing methods in terms of consistent generation and editing.", + "bbox": [ + 496, + 763, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Work done during an internship at ARC Lab, Tencent PCG.", + "bbox": [ + 99, + 886, + 423, + 900 + ], + "page_idx": 0 + }, + { + "type": "footer", + "text": "22560", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "For the text-to-image generation, we usually want to generate several images of the same objects/characters but with different views or complex non-rigid variances (e.g., the changes of posture). Such capabilities are urgently needed for creating comic books and generating short videos using existing powerful T2I image models. However, this requirement is highly challenging. Even if we fix the input random noise and use very similar prompts (e.g., 'a sitting cat' vs. 'a laying cat' shown in Fig. 2), the generated images vary in both structures and identity.", + "bbox": [ + 76, + 90, + 472, + 243 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "For text-conditioned image editing, existing methods [10, 35, 21] achieve impressive editing effects in image translation, stylization, and appearance replacement while keeping the input structure and scene layout unchanged. However, those methods usually fail to change poses or views while maintaining the overall textures and identity, leading to inconsistent editing results. The latter editing way is a more complicated non-rigid editing for practical use. Imagic [12] is then proposed to address this challenge. It allows complex non-rigid edits while preserving its original characteristics. It can make a standing dog sit down, cause a bird to spread its wings, etc. Nevertheless, it requires fine-tuning the entire T2I diffusion model and optimizing the textual embedding to capture the image-specific appearance for each edit, which is time-consuming and impractical for real-world applications.", + "bbox": [ + 76, + 246, + 472, + 488 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this paper, we aim to develop a tuning-free method to address the above challenges, enabling a more consistent generation of multiple images and complex non-rigid editing without fine-tuning. The core challenge is how to keep consistent. Unlike previous works [10, 21, 3] that usually operate on cross-attention in T2I models, we propose to convert existing self-attention to mutual self-attention, so that it can query correlated local structures and textures from a source image for consistency. Specifically, we first generate an image from a random (or inverted a real image) noise, resulting in the denoising process (DP1) for the source image synthesis. In the new denoising process (DP2) of generating a new image or editing an existing one, we can use the Query features in DP2 self-attention to query the corresponding Key and Value features in DP1 self-attention. In other words, we transform the existing self-attention into 'cross-attention', where the crossing operation happens in the self-attention of two related denoising processes, rather than between the U-Net features and text embeddings. We call this 'crossing self-attention as mutual self-attention. However, directly applying this strategy can only generate images almost identical to the source image and cannot comply with the target text prompt (as analyzed in Fig. 9). Thus we further control the denoising timestep and the layer position in U-Net for performing mutual self-attention to achieve consistent synthesis and editing. More analyses are in Sec. 4.1 and Sec. 5.5. In this", + "bbox": [ + 76, + 493, + 472, + 901 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/fc272f30003b45f0263635795511e6d1de79443672bf052a7e181bf7738f7073.jpg", + "image_caption": [ + "\"...sitting...\"" + ], + "image_footnote": [], + "bbox": [ + 504, + 90, + 632, + 189 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/13b42cee5fcc9c21834f61e69a72c2e5def9b65c41afd253f7206ef2422a7ac7.jpg", + "image_caption": [ + "...laying..." + ], + "image_footnote": [], + "bbox": [ + 632, + 90, + 759, + 189 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/4151ff38d4a99988f706d898202954d7e4e915f7a7305ae4b1f1a57537a31a0b.jpg", + "image_caption": [ + "...laying...\" (Ours)" + ], + "image_footnote": [], + "bbox": [ + 761, + 90, + 888, + 189 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/0f6bd7f93692c214017a6e8fa521850b6cd5381e84aed7e17a7694039bf03c1b.jpg", + "image_caption": [ + "Source" + ], + "image_footnote": [], + "bbox": [ + 503, + 205, + 632, + 305 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/0c9714560e8b87a6d2d166223941d717cfaf04ef2d73a8244ecece4f373ef1fc.jpg", + "image_caption": [ + "w/o mask guidance" + ], + "image_footnote": [], + "bbox": [ + 632, + 205, + 759, + 305 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/dda00ec7413d8f0ce4e2ad05618ad2f298cce5311fd424672db1d89929449c19.jpg", + "image_caption": [ + "with mask guidance", + "Figure 2: First row: images synthesized from fixed random seed (middle, changed identity) and our method (right, maintained identity). Second row: image synthesized without mask guidance (middle) and with mask guidance (right)." + ], + "image_footnote": [], + "bbox": [ + 761, + 205, + 888, + 305 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "way, we can use contents in the source image as the generation material to better maintain the texture and identity. Meanwhile, its structure, pose, and non-rigid variances can be controlled by target text prompt, and guided by recent controllable T2I-Adapters [17] or ControlNet [45]. Fig. 1 shows some synthesis and editing examples.", + "bbox": [ + 498, + 411, + 890, + 501 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The proposed mutual self-attention control can work well for images with disentangled foreground and background, but may fail in the synthesis and editing process where the foreground and background have similar patterns and colors. In these cases, mutual self-attention tends to confuse the foreground and background, leading to a messy result (2nd row in Fig. 2). To address this problem, we further propose a mask-guided mutual self-attention. Specifically, we first utilize the cross attention in T2I diffusion models to extract a mask associated with the main object in the image. This mask can successfully separate foreground and background, and restrict the target foreground/background features to query only foreground/background features of the source image, respectively. Such an operation can effectively alleviate the query confusion between the foreground and background.", + "bbox": [ + 496, + 503, + 892, + 746 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Our contributions can be summarized as follows. 1) We propose a tuning-free method, namely, MasaCtrl, to simultaneously achieve consistent image synthesis and complex non-rigid image editing. 2) An effective mutual self-attention mechanism with delicate designs is proposed to change pose, view, structures, and non-rigid variances while maintaining the characteristics, texture, and identity. 3) To alleviate the query confusion between foreground and background, we further propose a masked-guided mutual self-attention, where the mask can be easily computed from the", + "bbox": [ + 496, + 750, + 893, + 901 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "22561", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "cross-attentions. 4) Experimental results have shown the effectiveness of our proposed MasaCtrl in both consistent image generation and complex non-rigid real image editing.", + "bbox": [ + 75, + 90, + 468, + 137 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 76, + 151, + 218, + 166 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.1. Text-to-Image Generation", + "text_level": 1, + "bbox": [ + 76, + 176, + 312, + 193 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Early image generation methods conditioned on text description mainly based on GANs [26, 43, 44, 39, 14, 2, 46, 40, 42, 34], due to their powerful capability of high-fidelity image synthesis. These models try to align the text descriptions and synthesized image contents via multimodal vision-language learning and have achieved cheerful synthesis results on domain-specific datasets. Text-to-image generation with auto-regressive and diffusion models has obtained impressive diversity results. DALL-E [25], CogView [6] and Parti [41], large-scale text-to-image models trained with a large amount of data, enable generating images from open-domain text descriptions. However, the auto-regressive generation nature leads to the slow generation process defect. Most recently, diffusion models [32, 11, 20, 5] have shown superior generative power and achieved state-of-the-art synthesis results in terms of image quality and diversity than previous GAN-based and auto-regressive image generation models. By conditioning the text prompt into the diffusion model, various text-to-image diffusion models GLIDE [19], VQ-Diffusion [8], LDM [27], DALL-E 2 [24], and Imagen [30] have been developed. They can synthesize high-quality images that highly comply with the given text description.", + "bbox": [ + 75, + 200, + 472, + 549 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Text-guided Image Editing.", + "text_level": 1, + "bbox": [ + 76, + 559, + 321, + 575 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Text-guided image editing is a challenging task that aims to manipulate images according to natural language descriptions. Previous methods based on generative adversarial networks (GANs) [18, 15, 38, 22] have achieved some success on domain-specific datasets (e.g., face datasets), but they have limited applicability and generality. A recent approach based on auto-regressive models, VQGAN-CLIP [4], combines VQGAN [7] and CLIP [23] to produce high-quality images and precise edits with diverse and controllable results. However, this approach suffers from slow generation speed and high computational cost.", + "bbox": [ + 75, + 583, + 468, + 750 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Different from previous methods based on GANs or auto-regressive models, diffusion models offer a fast and efficient way to synthesize and edit images conditioned on text prompts. However, existing diffusion-based methods have some limitations regarding local and global editing. For example, the works [19, 1] require extra masks to edit local regions of the image; [13] can edit global aspects of the image by changing the text prompt directly, but cannot modify local details; [10, 35] use cross-attention or spatial features to edit both global and local aspects of the image", + "bbox": [ + 75, + 750, + 470, + 901 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "by changing the text prompt directly. Still, they tend to preserve the original layout of the source image and fail to handle non-rigid transformations (e.g., changing object pose). In contrast, we propose a novel approach that leverages the self-attention mechanism to achieve consistent and complex non-rigid image synthesis and editing. Our approach can modify various object attributes (e.g., pose, shape) by changing the text prompt accordingly. The most related work to ours is Imagic [12], which also enables various prompt-based non-rigid image editing. However, unlike our approach can edit images on the fly, Imagic requires careful optimization of the textual embedding and fine-tuning of the model, which is time-consuming and unfriendly for ordinary users.", + "bbox": [ + 496, + 90, + 893, + 303 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Preliminaries", + "text_level": 1, + "bbox": [ + 500, + 318, + 638, + 334 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Latent Diffusion Models", + "text_level": 1, + "bbox": [ + 500, + 343, + 723, + 359 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Diffusion models [11, 31, 20] are generative models that can synthesize desired data samples from Gaussian noise via iterative denoising. Our method is based on the recent state-of-the-art text-conditioned model Stable Diffusion (SD) [27], which performs the diffusion-denoising process in the latent rather than image space. Specifically, a pretrained image autoencoder first encodes the image $x$ into latent representations $z$ . Then the denoising network $\\epsilon_{\\theta}$ (a time-conditional U-Net [28]) is trained in this latent space. After being trained, we can sample a random noise $z_{T} \\sim \\mathcal{N}(0,1)$ and perform the latent denoising process. The denoised latent representation $z_{0}$ can be decoded into an image using the pretrained autoencoder.", + "bbox": [ + 496, + 367, + 893, + 565 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Attention Mechanism in Stable Diffusion", + "text_level": 1, + "bbox": [ + 500, + 575, + 849, + 590 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The denoising U-Net $\\epsilon_{\\theta}$ in the SD model, consists of a series of basic blocks, and each basic block contains a residual block [9], a self-attention module, and a cross-attention [36] module. At denoising step $t$ , the features from the previous $(l - 1)$ -th basic block first pass through the residual block to generate intermediate features $f_{t}^{l}$ ; then they are reorganized by the self-attention layer, and receive textual information from the text prompt $P$ by the following cross-attention layer. The attention mechanism can be formulated as follows:", + "bbox": [ + 496, + 599, + 893, + 750 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {A t t e n t i o n} (Q, K, V) = \\operatorname {S o f t m a x} \\left(\\frac {Q K ^ {T}}{\\sqrt {d}}\\right) V, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 555, + 760, + 890, + 795 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $Q$ is the query features projected from the spatial features, and $K, V$ are the key and value features projected from the spatial features (in self-attention layers) or the textual embedding (in cross-attention layers) with corresponding projection matrices. $A = \\operatorname{Softmax}\\left(\\frac{QK^T}{\\sqrt{d}}\\right)$ is the attention map used to aggregate the value $V$ .", + "bbox": [ + 496, + 805, + 893, + 902 + ], + "page_idx": 2 + }, + { + "type": "footer", + "text": "22562", + "bbox": [ + 478, + 925, + 519, + 936 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/544b0184a63e05419f081618b6a5d83cbbdb4c6fcb88d7b76308dc53997e26b1.jpg", + "image_caption": [ + "Figure 3: Pipeline of the proposed MasaCtrl. Our method tries to perform complex non-rigid image editing and synthesize content-consistent images. The source image is either real or synthesized with source text prompt $P_{s}$ . During the denoising process for image synthesis, we convert the self-attention into mutual self-attention to query image contents from source image $I_{s}$ , so that we can synthesize content-consist images under the modified target prompt $P$ ." + ], + "image_footnote": [], + "bbox": [ + 83, + 88, + 883, + 369 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "These attention layers in the SD model contain much information for the overall structure/layout and content formation of the synthesized image [10, 35]. The internal cross-attention maps are high-dimensional tensors that bind the spatial pixels and textual embedding [10], and they are explored for image editing [10] and faithful image synthesis [3]. In addition, the features in the self-attention layer are employed as plug-and-play features to be injected into specified U-Net layers to perform image translation. However, these controls cannot perform non-rigid editing (e.g., pose change) since they maintain the semantic layout and structures. Inspired by the phenomenon that performing self-attention across batches can generate similar image contents, which is also observed in Tune-A-Video [37], we adapt the self-attention mechanism in the T2I model to query contents from source images with delicate designs. Thus we can perform consistent synthesis and non-rigid editing that change the layout and structure of the source image while preserving image contents.", + "bbox": [ + 75, + 468, + 472, + 758 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. Tuning-Free Mutual Self-Attention Control", + "text_level": 1, + "bbox": [ + 76, + 768, + 465, + 787 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Given a source image $I_{s}$ and the corresponding text prompt $P_{s}$ , our goal is to synthesize the desired image $I$ that complies with the target edited text prompt $P$ (directly modified from $P_{s}$ ). Note that the edited target image $I$ is spatially edited from $I_{s}$ and should preserve the object contents (e.g., textures and identity) in $I_{s}$ . For instance, consider a photo (corresponding to $P_{s}$ ) where a dog is sitting,", + "bbox": [ + 75, + 795, + 470, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "and we want the dog to be in the running pose with the edited text prompt $P$ that adds the 'running' into the source prompt $P_{s}$ (see Fig. 3).", + "bbox": [ + 496, + 468, + 890, + 513 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Our core idea is to combine the semantic layout synthesized with the target prompt $P$ and the contents in the source image $I_{s}$ to synthesize the desired image $I$ . To achieve so, we propose MasaCtrl, which adapts the self-attention mechanism in the SD model into a crossing one to query semantically similar contents from the source image. Consequently, the target image $I$ can be synthesized by querying the contents from $I_{s}$ with the modified self-attention mechanism during the denoising process. We can achieve so for the following reasons: 1) the image layout is formed in the early denoising steps (shown in Fig. 4(a)); 2) in addition, as shown in Fig. 4(b), the encoded query features in the self-attention layer are semantically corresponded (e.g., the horses are in the same color), thus one can query content information from another.", + "bbox": [ + 496, + 515, + 892, + 741 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The overall architecture of the proposed pipeline to perform synthesis and editing is shown in Fig. 3, and the algorithm is summarized in Alg. 1. The input source image $I_{s}$ is either a real image or a generated one from the SD model with text prompt $P_{s}$ . During each denoising step $t$ of synthesizing target image $I$ , we assemble the inputs of", + "bbox": [ + 496, + 743, + 893, + 835 + ], + "page_idx": 3 + }, + { + "type": "page_footnote", + "text": "1When $I_{s}$ is a real image, we set the text prompt $P_{s}$ as null and utilize the deterministic DDIM inversion [31] to obtain the initial noise map. When $I_{s}$ is an image synthesized with prompt $P_{s}$ , the initial noise map is the same as the one used to synthesize $I_{s}$ .", + "bbox": [ + 498, + 849, + 893, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "22563", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Algorithm 1 MasaCtrl: Tuning-Free Mutual Self-Attention Control", + "bbox": [ + 76, + 90, + 468, + 118 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Input: A source prompt $P_{s}$ , a modified prompt $P$ , the source and target initial latent noise maps $z_{T}^{s}$ and $z_{T}$ .", + "bbox": [ + 76, + 119, + 467, + 151 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Output: Latent map $z_0^s$ , edited latent map $z_0$ corresponding to $P_s$ and $P$ .", + "bbox": [ + 76, + 151, + 467, + 179 + ], + "page_idx": 4 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1: for $t = T, T - 1, \\ldots, 1$ do", + "2: $\\epsilon_s, \\{Q_s, K_s, V_s\\} \\gets \\epsilon_\\theta(z_t^s, P_s, t)$ ;", + "3: $z_{t - 1}^{s}\\gets \\mathrm{Sample}(z_{t}^{s},\\epsilon_{s})$", + "4: $\\{Q,K,V\\} \\gets \\epsilon_{\\theta}(z_t,P,t)$", + "5: $\\{Q^{*},K^{*},V^{*}\\} \\leftarrow$ EDIT( $\\{Q,K,V\\},\\{Q_{s},K_{s},V_{s}\\}$ );", + "6: $\\epsilon = \\epsilon_{\\theta}(z_t,P,t;\\{Q^*,K^*,V^*\\})$", + "7: $z_{t - 1}\\gets \\mathrm{Sample}(z_t,\\epsilon);$", + "8: end for" + ], + "bbox": [ + 88, + 183, + 460, + 301 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Return $z_0^s, z_0$", + "bbox": [ + 78, + 306, + 171, + 321 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "the self-attention by 1) keeping the current Query features $Q$ unchanged, and 2) obtaining the Key and Value features $K_{s}$ , $V_{s}$ from the self-attention layer in the process of synthesizing source image $I_{s}$ . We dub this strategy mutual self-attention, and more details are in Sec. 4.1.", + "bbox": [ + 76, + 351, + 467, + 425 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Meanwhile, we also observe the edited image often suffers from the problem of confusion between the foreground objects and background. Thus, we propose a mask-aware mutual self-attention strategy guided by the masks obtained from the cross-attention mechanism. The object mask is automatically generated from the cross-attention maps of the text token associated with the foreground object. Please refer to Sec. 4.2 for more details.", + "bbox": [ + 75, + 426, + 467, + 546 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In addition, since the edited prompt $P$ may not yield desired spatial layouts due to the inner limitations of the SD model, MasaCtrl can be easily integrated into existing controllable image synthesis method (e.g., T2I-Adapter [17] and ControlNet [45]) for more faithful non-rigid image editing. Please refer to Sec. 4.3 for more details.", + "bbox": [ + 75, + 547, + 467, + 638 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Mutual Self-Attention", + "text_level": 1, + "bbox": [ + 76, + 648, + 282, + 664 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "As shown in the left part of Fig. 5(a), at denoising step $t$ and layer $l$ , the query features are defined as the projected query features $Q^l$ in the self-attention module, and the content features are the key features $K_s^l$ and value features $V_s^l$ from the corresponding self-attention layer in the process of reconstructing the source image $I_s$ . After that, we perform attention according to Eq. 1 to aggregate the contents from the source image.", + "bbox": [ + 75, + 672, + 467, + 792 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "However, intuitively performing such attention on all layers among all denoising steps will result in a failed image $I$ that is nearly the same as the reconstructed image $I_{s}$ . We argue the reason is that performing self-attention control in the early steps can disrupt the layout formation of the target image. In the premature denoising steps, the target image layout has not yet been formed (shown in Fig. 4(a)).", + "bbox": [ + 75, + 795, + 467, + 900 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/8104f59f1e064b84f081b37a5ff4c779c280e77a747a173fa51b79500b78ba98.jpg", + "image_caption": [ + "(a) Intermediate results in denoising process" + ], + "image_footnote": [], + "bbox": [ + 504, + 89, + 887, + 186 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/5fd292d44cab9e25505b8168b7eb06ccfdf0336af66d0339a21081731ef43180.jpg", + "image_caption": [ + "(b) Query feature visualization", + "Figure 4: (a) The intermediate results during the iterative denoising process, and (b) visualization of the projected Query features $Q$ in the self-attention layers of the U-Net at the 15th sampling step." + ], + "image_footnote": [], + "bbox": [ + 524, + 199, + 887, + 311 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We further observe the Query features in the shallow layers of U-Net (e.g., encoder part) cannot obtain clear layout and structure corresponding to the modified prompt (shown in Fig. 4(b)). Thus we cannot obtain the image with the desired spatial layout.", + "bbox": [ + 496, + 428, + 890, + 503 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Therefore, we propose to control the mutual self-attention only in the decoder part of the $U$ -Net after several denoising steps, due to the formed clear target image layout and semantically similar features (see Fig. 4). We can change the original layout into the target one with edited prompt $P$ and keep the main objects unchanged with proper starting denoising step $S$ and layer $L$ for synthesis and editing. Thus the EDIT function in Alg. 1 can be formulated as follows:", + "bbox": [ + 496, + 508, + 890, + 643 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {E D I T} := \\left\\{ \\begin{array}{l l} \\left\\{Q, K _ {s}, V _ {s} \\right\\}, & \\text {i f} \\quad T - t > S \\quad \\text {a n d} \\quad l > L, \\\\ \\left\\{Q, K, V \\right\\}, & \\text {o t h e r w i s e ,} \\end{array} \\right. \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 501, + 661, + 890, + 714 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $S$ and $L$ are the timestep and layer index to start attention control, respectively. $T$ is the total denoising steps.", + "bbox": [ + 496, + 714, + 888, + 744 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In the early steps, the composition and shape of the object can be roughly generated, complying with the target prompt $P$ . Then the content information from the source image $I_{s}$ is queried by the mutual self-attention mechanism to fill the generated layout of target image $I$ . After iterative denoising, we can obtain the synthesized image with similar contents in the source image and structure of $I^{*}$ that complied with the input prompt. Note that our algorithm does not require fine-tuning or optimization, bringing many conveniences for ordinary users for content creation.", + "bbox": [ + 496, + 750, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "22564", + "bbox": [ + 478, + 925, + 517, + 936 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/8e1baa964161870e1099e38361e2c753df020ba7575ab50b8336fd28cd4faca4.jpg", + "image_caption": [ + "(a) Mutual self-attention control" + ], + "image_footnote": [], + "bbox": [ + 81, + 88, + 467, + 231 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/a9305591d9c94c8220f85a9113f75708751b2136a6be26cc40629e355473ded0.jpg", + "image_caption": [ + "(b) Mask extraction from cross-attention maps", + "Figure 5: (a) The mutual self-attention mechanism and control strategy in the decoder part of denoising U-Net to query contents from the source image; and (b) mask extraction strategy from cross-attention maps." + ], + "image_footnote": [], + "bbox": [ + 83, + 253, + 464, + 402 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Mask-Guided Mutual Self-Attention", + "text_level": 1, + "bbox": [ + 76, + 525, + 392, + 540 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We also observed the above synthesis/editing would fail when the object and background are too similar to be confused. One feasible way to tackle this problem is to segment the image into the foreground and background parts and query contents only from the corresponding parts. Inspired by previous work [10, 33], the cross-attention maps correlating to the prompt tokens contain most information of the shape and structure. Therefore, we utilize the semantic cross-attention maps to create a mask to distinguish the foreground and background in both source and target images $I_{s}$ and $I$ .", + "bbox": [ + 75, + 558, + 468, + 724 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Specifically, at step $t$ , we first perform forward passes with source prompt $P_{s}$ and edited prompt $P$ , respectively, to generate intermediate cross-attention maps. Then we average the cross-attention maps across all heads and layers with the spatial resolution $16 \\times 16$ . The resulting cross-attention maps are denoted as $A_{t}^{c} \\in \\mathbb{R}^{16 \\times 16 \\times N}$ , where $N$ is the number of the textual tokens. We then obtain the averaged cross-attention map for the token correlated to the foreground object. We denote $M_{s}$ and $M$ as masks extracted for the foreground objects in $I_{s}$ and $I$ , respectively. With these masks, we can restrict the object in $I$ to query", + "bbox": [ + 75, + 734, + 470, + 902 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "contents information only from the object region in $I_{s}$ :", + "bbox": [ + 498, + 90, + 857, + 106 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\nf _ {o} ^ {l} = \\text {A t t e n t i o n} \\left(Q ^ {l}, K _ {s} ^ {l}, V _ {s} ^ {l}; M _ {s}\\right), \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 568, + 109, + 890, + 128 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\nf _ {b} ^ {l} = \\text {A t t e n t i o n} \\left(Q ^ {l}, K _ {s} ^ {l}, V _ {s} ^ {l}; 1 - M _ {s}\\right), \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 571, + 132, + 890, + 148 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\bar {f} ^ {l} = f _ {o} ^ {l} * M + f _ {b} ^ {l} * (1 - M), \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 571, + 152, + 890, + 170 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $\\bar{f}^l$ is the final attention output. The object and background regions in the target image query the contents from corresponding restricted areas rather than all source image features. Note that this strategy is optional and used when confusion occurs.", + "bbox": [ + 496, + 176, + 890, + 252 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Integration to Controllable Diffusion Models", + "text_level": 1, + "bbox": [ + 498, + 260, + 879, + 276 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Our method can be integrated into existing controllable diffusion models (e.g., T2I-Adapter [17] and ControlNet [45]) for more faithful non-rigid image synthesis and editing. These methods enable the original Stable Diffusion model to be more controllable (e.g., pose, sketch, segmentation map) in image synthesis. Thus we can use them to synthesize images with desired poses and shapes. Since our method can query image contents (e.g., textures) from a reference image, we can easily integrate our approach into these models to generate more consistent images.", + "bbox": [ + 496, + 282, + 890, + 434 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Specifically, we follow the same process depicted in Alg. 1, and the desired target image synthesis process is changed from the original SD model to using these controllable models instead. In the following experiment section, we demonstrate the effectiveness of such a combination that can synthesize images consistently.", + "bbox": [ + 496, + 434, + 890, + 525 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 500, + 532, + 633, + 550 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Setup. We apply the proposed method to the state-of-the-art text-to-image Stable Diffusion [27] model with publicly available checkpoints v1.4. We also validate the proposed method on the pre-trained anime-style model Anything-V4. Meanwhile, we perform editing on both synthetic images and real images. For real image editing, we first invert the image into the initial noise map with DDIM deterministic inversion [31]. Note that we set the starting noise map the same for source prompt $P_{s}$ and the desired prompt $P$ unless otherwise specified. During sampling, we perform DDIM sampling [31] with 50 denoising steps, and the classifier-free guidance is set to 7.5. The step and layer to start attention control is set to $S = 4$ , $L = 10$ as default. Note that it may be changed for specific checkpoints.", + "bbox": [ + 496, + 558, + 890, + 768 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Comparisons with Previous Works", + "text_level": 1, + "bbox": [ + 500, + 773, + 802, + 787 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We mainly compare the proposed tuning-free method to the current prompt-based editing methods with diffusion models, including tuning-free methods SDEdit [16], P2P [10], PnP [35], and Imagc [12]. We use their open-sourced codes to produce the editing results2.", + "bbox": [ + 496, + 792, + 890, + 868 + ], + "page_idx": 5 + }, + { + "type": "page_footnote", + "text": "2We adopt the community version of Imagic as the official source code is not open-sourced", + "bbox": [ + 500, + 875, + 890, + 898 + ], + "page_idx": 5 + }, + { + "type": "footer", + "text": "22565", + "bbox": [ + 478, + 925, + 517, + 936 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/7e8cd60ed70b342e7d572ae83f21cbbc09ff5b5b74c6af4eac910904178ab54e.jpg", + "image_caption": [ + "Figure 6: Editing results of different methods on the synthetic images (a) and real images (b). Our method enables consistent synthesis by combining the layout of the target prompt and the contents of source generated image. From left to right: the source generated source image with source prompt, synthesis results with the proposed MasaCtrl method, synthesis results from target prompt with the same random noise of source image, synthesis/editing results with existing methods P2P [10], SDEdit [16], PnP [35], and Imagc [12]." + ], + "image_footnote": [], + "bbox": [ + 83, + 85, + 890, + 470 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/61d3aaf56ab96999494c435e35833206ec53446ba1c0dbb8353d4736c9f401c1.jpg", + "image_caption": [ + "Figure 7: Editing results of synthetic images (left part) and real images (right part) with MasaCtrl integrated into T2I-Adapter [17]." + ], + "image_footnote": [], + "bbox": [ + 76, + 569, + 472, + 715 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Qualitative comparison. The consistent synthesis results are shown in Fig. 6(a). By directly modifying the text prompt, our method can synthesize content-consistent images. These synthesized images (1) contain contents (foreground objects and background) that are highly similar to those in the generated source images (first column of Fig. 6) and (2) highly comply with the target prompt $P$ (third col", + "bbox": [ + 75, + 784, + 472, + 891 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/b7b62ebe10786e9a150e928bc268d39462bd8090767b1988986e6d4805fcd794.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 496, + 569, + 890, + 715 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "unn of Fig. 6). While existing methods fail to synthesize desired images, either conforming to the target text prompt or inconsistent with the source images. Our method also achieves promising results in editing real images shown in Fig. 6(b). The edited image is consistent with the target prompt and maintains source image content. These results demonstrate the effectiveness of the proposed method.", + "bbox": [ + 496, + 784, + 893, + 891 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "22566", + "bbox": [ + 478, + 925, + 519, + 936 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/44b04ab1a0e4304da209bc6bbc5a5e6656cf732ad8c556f0fe943d15c0c352f3.jpg", + "image_caption": [ + "Figure 8: Video synthesis results of proposed MasaCtrl with T2I-Adapter [17] (with key-pose guidance)." + ], + "image_footnote": [], + "bbox": [ + 80, + 89, + 893, + 210 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Quantitative comparison. For quantitative evaluation, we used 20 different source images (10 are synthetic and 10 are real) and edited them with P2P, PnP, Imagic, and MasaCtrl. We evaluate the text-alignment between the target prompt and edited image, and the image-alignment between the source and edited images in the CLIP feature space. Tab. 1 shows that MasaCtrl can synthesize images that comply with the target prompt while maintaining content consistency more than other methods. We also conducted a user study and collected 700 answers from professional participants. As shown in the preference column of Tab. 1, $73.5\\%$ of participants preferred our method. Meanwhile, our method is efficient since no fine-tuning and optimization are required.", + "bbox": [ + 75, + 262, + 468, + 474 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We further analyze the reasons attributed to the failure of existing methods (i.e., P2P, SDEdit, and PnP). These methods try to keep the original layout or object shape and pose unchanged by leveraging the layout information encoded in the cross-attention maps (P2P), features (PnP), and original input images (SDEdit). Meanwhile, the contents in the formed image mainly come from the encoded text embedding. As a result, the images synthesized by these methods have similar layouts to the source image but have different contents. In our proposed method MasaCtrl, the structure of the desired image is first determined by the former iteration in the denoising process, and the final image is formed by obtaining the image content from the source image. Thus we can perform various types of non-rigid image editing.", + "bbox": [ + 75, + 474, + 468, + 686 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.2. Results with T2I-Adapter", + "text_level": 1, + "bbox": [ + 76, + 693, + 308, + 709 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "The initial layout controlled by modifying the text prompt usually fails due to the inherent drawbacks of the Stable Diffusion model. Therefore, we further integrate our method into existing controllable synthesis pipelines to obtain stable synthesis and editing results. The synthetic and real image editing results of MasaCtrl with T2I-", + "bbox": [ + 75, + 713, + 467, + 804 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/2ea4ba4cf19b8da617f804c0a2e009266143c0549c64be8c6e6dcedcc6d7a5ed.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodText-alignmentImage-alignmentPreferenceRuntime
P2P [10]0.26910.87933.0%15s
PnP [35]0.25890.89022.5%60s
Imagic [12]0.26880.915921.0%14min
Ours0.27930.928673.5%16s
", + "bbox": [ + 81, + 809, + 465, + 869 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 1: Quantitative and user study results.", + "bbox": [ + 127, + 881, + 416, + 895 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Adapter [17] are shown in Fig. 7. We see that T2I-Adapter can generate an image with desired target layout, yet with different contents in the source image. In contrast, our method can effectively combine the layout synthesized by T2I-Adapter with the target prompt and the contents in the source image. Therefore, more faithful and fine-grained synthesis and editing results can be obtained. Note that we may change the attention strategy of starting denoising step $S$ and U-Net layer $L$ to obtain faithful results ( $S = 2$ , $L = 8$ in our experiment), since the target layout is strongly controlled by extra guidance. Therefore, we can perform attention control in early steps and layers to query faithful contents in the source image, refer to the ablation study Sec. 5.5 for the analysis.", + "bbox": [ + 496, + 262, + 890, + 474 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.3. Robustness to Other Models", + "text_level": 1, + "bbox": [ + 500, + 482, + 751, + 497 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Our method can be applied to other versions of Stable Diffusion models (e.g., v1.5), domain-specific models (e.g., the amine-style model Anything-v4), and customized models (e.g., models fine-tuned with DreamBooth [29]) to achieve consistent image synthesis and editing. Please refer to the supplementary materials for the visual results.", + "bbox": [ + 496, + 506, + 890, + 597 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4. Extension to Video Synthesis", + "text_level": 1, + "bbox": [ + 500, + 604, + 756, + 621 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Although our method is designed for consistent image synthesis and editing, we can easily extend our method for the video synthesis task using T2I-Adapter and ControlNet with a series of dense temporal-coherent guidance (e.g., pose, edge, depth). Specifically, we first generate a source image with the prompt $P_{s}$ and guidance as the canonical frame (shown in the first column of Fig. 8). The other frames are synthesized separately with MasaCtrl. Then all the synthesized frames can be concatenated into a video since they are content-consistent with the source frame. Fig. 8 shows the video synthesis results with coherent dense guidance. The proposed method successfully synthesizes consistent frames with highly similar content (more video results are available on the project page and supplementary materials). However, our method can only animate the foreground objects (such as the bear in Fig. 8) and hardly bring the background alive. Therefore, video-based approaches still need to be explored since the current MasaCtrl has", + "bbox": [ + 496, + 628, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "22567", + "bbox": [ + 478, + 925, + 517, + 936 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/039fd558c9fa8f06f3c107ba23d87462b8aab3e79b08806e755ec597eeb96827.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 86, + 88, + 359, + 200 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/3b95bc034362513c8e21e16b0e2fa7bb409bbca8b2ea333cb358f4527e43e5bc.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 369, + 88, + 887, + 202 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/de95c48bb13b21a25fb6973b50b5f136dcdfb54526a0d1578d42e161257d54b0.jpg", + "image_caption": [ + "(a) Results of mutual self-attention control starting from different denoising steps", + "(b) Results of mutual self-attention control in different U-Net layers", + "Figure 9: Results of mutual self-attention control in different denoising steps (a) and different U-Net layers (b). We see that only performing mutual self-attention control after several denoising steps (e.g., step 5), and in the decoder part (e.g., layer $10 \\sim 15$ ) can preserve the shape and structure information from target prompt $P$ and query contents from the source image with prompt $P_{s}$ ." + ], + "image_footnote": [], + "bbox": [ + 81, + 222, + 890, + 335 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "a significant limitation in synthesizing scenes with background dynamics.", + "bbox": [ + 75, + 452, + 470, + 482 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5.5. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 496, + 230, + 512 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "The results of both synthetic and real image editing can demonstrate the effectiveness of the proposed mutual self-attention control. We further analyze the control strategy in terms of different starting steps at the denoising process and the layers in the denoising U-Net. From Fig. 9(a), we see that performing mutual self-attention in the premature step can only synthesize an image identical to the source image, conveying all source image contents and ignoring the layout from the target prompt. As the step increases, the synthesized desired image can maintain the layout from the target prompt and the contents from the source image. While the image would gradually lose the source image contents and eventually becomes the image synthesized images without mutual self-attention control. We also observe a similar phenomenon when performing control in different U-Net layers shown in Fig. 9(b). Performing control among all layers can only generate an image identical to the source image. Performing control in low-resolution layers (i.e., layer $4 \\sim 10$ ) cannot preserve the source image contents and target layouts. While in high-resolution layers (i.e., layer $0 \\sim 3$ , $10 \\sim 15$ ), the target layout can be maintained, and the source image contents can only be transformed when controlled in the decoder part. As a result, the proposed method performs control in the decoder part of U-Net after several denoising steps.", + "bbox": [ + 75, + 523, + 472, + 902 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Limitations and Discussion", + "text_level": 1, + "bbox": [ + 500, + 450, + 751, + 465 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Our method inherits most of the limitations of the Stable Diffusion model in generating desired images with text prompts. Please refer to the supplementary materials for detailed analysis and discussion. In addition, when editing real images, the DDIM inversion may fail to reconstruct the source images. In this case, MasaCtrl would fail to edit these images.", + "bbox": [ + 496, + 476, + 892, + 582 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "7. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 595, + 619, + 609 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We propose MasaCtrl, a tuning-free mutual self-attention control method applied to T2I diffusion models for non-rigid consistent image synthesis and editing. We convert the self-attention mechanism in diffusion models into a cross one, dubbed mutual self-attention, enabling effective structure and appearance query from the source image when applied to specific denoising steps and U-Net layers. We further consider the confusion problem of the foreground objects and background during the querying process and alleviate it with a mask-guided strategy. Meanwhile, our method can be easily integrated into recently proposed controllable strategies over diffusion models and perform consistent image synthesis and editing without fine-tuning the model and textural embedding. We believe such a method provides ordinary users with a convenient and effective way for content creation under text description.", + "bbox": [ + 496, + 619, + 893, + 864 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement. This research was partly supported by JSPS KAKENHI Grant Numbers 22H00529, 20H05951.", + "bbox": [ + 498, + 869, + 892, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "22568", + "bbox": [ + 478, + 925, + 519, + 936 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Omri Avrahami, Ohad Fried, and Dani Lischinski. Blended latent diffusion. arXiv preprint arXiv:2206.02779, 2022.", + "[2] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. arXiv preprint arXiv:1809.11096, 2018.", + "[3] Hila Chefer, Yuval Alaluf, Yael Vinker, Lior Wolf, and Daniel Cohen-Or. Attend-and-excite: Attention-based semantic guidance for text-to-image diffusion models. arXiv preprint arXiv:2301.13826, 2023.", + "[4] Katherine Crowson, Stella Biderman, Daniel Kornis, Dashiell Stander, Eric Hallahan, Louis Castricato, and Edward Raff. Vqgan-clip: Open domain image generation and editing with natural language guidance. In ECCV, pages 88–105. Springer, 2022.", + "[5] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. NeurIPS, 34:8780-8794, 2021.", + "[6] Ming Ding, Zhuoyi Yang, Wenyi Hong, Wendi Zheng, Chang Zhou, Da Yin, Junyang Lin, Xu Zou, Zhou Shao, Hongxia Yang, et al. Cogview: Mastering text-to-image generation via transformers. NeurIPS, 34:19822-19835, 2021.", + "[7] Patrick Esser, Robin Rombach, and Bjorn Ommer. Taming transformers for high-resolution image synthesis. In CVPR, pages 12873-12883, 2021.", + "[8] Shuyang Gu, Dong Chen, Jianmin Bao, Fang Wen, Bo Zhang, Dongdong Chen, Lu Yuan, and Baining Guo. Vector quantized diffusion model for text-to-image synthesis. In CVPR, pages 10696-10706, 2022.", + "[9] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778, 2016.", + "[10] Amir Hertz, Ron Mokady, Jay Tenenbaum, Kfir Aberman, Yael Pritch, and Daniel Cohen-Or. Prompt-to-prompt image editing with cross attention control. arXiv preprint arXiv:2208.01626, 2022.", + "[11] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. NeurIPS, 33:6840-6851, 2020.", + "[12] Bahjat Kawar, Shiran Zada, Oran Lang, Omer Tov, Huiwen Chang, Tali Dekel, Inbar Mosseri, and Michal Irani. Imagc: Text-based real image editing with diffusion models. arXiv preprint arXiv:2210.09276, 2022.", + "[13] Gwanghyun Kim, Taesung Kwon, and Jong Chul Ye. Diffusionclip: Text-guided diffusion models for robust image manipulation. In CVPR, pages 2426-2435, 2022.", + "[14] Bowen Li, Xiaojuan Qi, Thomas Lukasiewicz, and Philip Torr. Controllable text-to-image generation. NeurIPS, 32, 2019.", + "[15] Bowen Li, Xiaojuan Qi, Thomas Lukasiewicz, and Philip HS Torr. Manigan: Text-guided image manipulation. In CVPR, pages 7880-7889, 2020.", + "[16] Chenlin Meng, Yang Song, Jiaming Song, Jiajun Wu, JunYan Zhu, and Stefano Ermon. Sdedit: Image synthesis and editing with stochastic differential equations. arXiv preprint arXiv:2108.01073, 2021.", + "[17] Chong Mou, Xintao Wang, Liangbin Xie, Jian Zhang, Zhonggang Qi, Ying Shan, and Xiaohu Qie. T2i-adapter: Learning" + ], + "bbox": [ + 78, + 114, + 467, + 901 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "adapters to dig out more controllable ability for text-to-image diffusion models. arXiv preprint arXiv:2302.08453, 2023.", + "[18] Seonghyeon Nam, Yunji Kim, and Seon Joo Kim. Text-adaptive generative adversarial networks: manipulating images with natural language. NeurIPS, 31, 2018.", + "[19] Alex Nichol, Prafulla Dhariwal, Aditya Ramesh, Pranav Shyam, Pamela Mishkin, Bob McGrew, Ilya Sutskever, and Mark Chen. Glide: Towards photorealistic image generation and editing with text-guided diffusion models. arXiv preprint arXiv:2112.10741, 2021.", + "[20] Alexander Quinn Nichol and Prafulla Dhariwal. Improved denoising diffusion probabilistic models. In ICML, pages 8162-8171. PMLR, 2021.", + "[21] Gaurav Parmar, Krishna Kumar Singh, Richard Zhang, Yijun Li, Jingwan Lu, and Jun-Yan Zhu. Zero-shot image-to-image translation. arXiv preprint arXiv:2302.03027, 2023.", + "[22] Or Patashnik, Zongze Wu, Eli Shechtman, Daniel Cohen-Or, and Dani Lischinski. Styleclip: Text-driven manipulation of stylegan imagery. In ICCV, pages 2085–2094, 2021.", + "[23] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In ICML, pages 8748-8763. PMLR, 2021.", + "[24] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022.", + "[25] Aditya Ramesh, Mikhail Pavlov, Gabriel Goh, Scott Gray, Chelsea Voss, Alec Radford, Mark Chen, and Ilya Sutskever. Zero-shot text-to-image generation. In ICML, pages 8821-8831. PMLR, 2021.", + "[26] Scott Reed, Zeynep Akata, Xinchen Yan, Lajanugen Logeswaran, Bernt Schiele, and Honglak Lee. Generative adversarial text to image synthesis. In ICML, pages 1060-1069. PMLR, 2016.", + "[27] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In CVPR, pages 10684-10695, 2022.", + "[28] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In MICCAI, pages 234-241. Springer, 2015.", + "[29] Nataniel Ruiz, Yuanzhen Li, Varun Jampani, Yael Pritch, Michael Rubinstein, and Kfir Aberman. Dreambooth: Fine tuning text-to-image diffusion models for subject-driven generation. arXiv preprint arXiv:2208.12242, 2022.", + "[30] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022.", + "[31] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. arXiv preprint arXiv:2010.02502, 2020.", + "[32] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. NeurIPS, 32, 2019." + ], + "bbox": [ + 503, + 92, + 890, + 901 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "22569", + "bbox": [ + 478, + 925, + 519, + 936 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[33] Raphael Tang, Akshit Pandey, Zhiying Jiang, Gefei Yang, Karun Kumar, Jimmy Lin, and Ferhan Ture. What the daam: Interpreting stable diffusion using cross attention. arXiv preprint arXiv:2210.04885, 2022.", + "[34] Ming Tao, Hao Tang, Fei Wu, Xiao-Yuan Jing, Bing-Kun Bao, and Changsheng Xu. Df-gan: A simple and effective baseline for text-to-image synthesis. In CVPR, pages 16515-16525, 2022.", + "[35] Narek Tumanyan, Michal Geyer, Shai Bagon, and Tali Dekel. Plug-and-play diffusion features for text-driven image-to-image translation. arXiv preprint arXiv:2211.12572, 2022.", + "[36] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. NeurIPS, 30, 2017.", + "[37] Jay Zhangjie Wu, Yixiao Ge, Xintao Wang, Weixian Lei, Yuchao Gu, Wynne Hsu, Ying Shan, Xiaohu Qie, and Mike Zheng Shou. Tune-a-video: One-shot tuning of image diffusion models for text-to-video generation. arXiv preprint arXiv:2212.11565, 2022.", + "[38] Weihao Xia, Yujiu Yang, Jing-Hao Xue, and Baoyuan Wu. Tedigan: Text-guided diverse face image generation and manipulation. In CVPR, pages 2256-2265, 2021.", + "[39] Tao Xu, Pengchuan Zhang, Qiuyuan Huang, Han Zhang, Zhe Gan, Xiaolei Huang, and Xiaodong He. Attngan: Fine-grained text to image generation with attentional generative adversarial networks. In CVPR, pages 1316-1324, 2018.", + "[40] Hui Ye, Xiulong Yang, Martin Takac, Rajshekhar Sunderraman, and Shihao Ji. Improving text-to-image synthesis using contrastive learning. arXiv preprint arXiv:2107.02423, 2021.", + "[41] Jiahui Yu, Yuanzhong Xu, Jing Yu Koh, Thang Luong, Gunjan Baid, Zirui Wang, Vijay Vasudevan, Alexander Ku, Yinfei Yang, Burcu Karagol Ayan, et al. Scaling autoregressive models for content-rich text-to-image generation. arXiv preprint arXiv:2206.10789, 2022.", + "[42] Han Zhang, Jing Yu Koh, Jason Baldridge, Honglak Lee, and Yinfei Yang. Cross-modal contrastive learning for text-to-image generation. In CVPR, pages 833-842, 2021.", + "[43] Han Zhang, Tao Xu, Hongsheng Li, Shaoting Zhang, Xiaogang Wang, Xiaolei Huang, and Dimitris N Metaxas. Stackgan: Text to photo-realistic image synthesis with stacked generative adversarial networks. In ICCV, pages 5907-5915, 2017.", + "[44] Han Zhang, Tao Xu, Hongsheng Li, Shaoting Zhang, Xiaogang Wang, Xiaolei Huang, and Dimitris N Metaxas. Stackgan++: Realistic image synthesis with stacked generative adversarial networks. IEEE TPAMI, 41(8):1947-1962, 2018.", + "[45] Lvmin Zhang and Maneesh Agrawala. Adding conditional control to text-to-image diffusion models. arXiv preprint arXiv:2302.05543, 2023.", + "[46] Minfeng Zhu, Pingbo Pan, Wei Chen, and Yi Yang. Dm-gan: Dynamic memory generative adversarial networks for text-to-image synthesis. In CVPR, pages 5802-5810, 2019." + ], + "bbox": [ + 78, + 90, + 470, + 856 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "22570", + "bbox": [ + 478, + 926, + 519, + 936 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/6e476140-cab6-422d-9817-a489e1ead454_model.json b/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/6e476140-cab6-422d-9817-a489e1ead454_model.json new file mode 100644 index 0000000000000000000000000000000000000000..a8a396726508070056a4e6957d54f2eee47a758c --- /dev/null +++ b/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/6e476140-cab6-422d-9817-a489e1ead454_model.json @@ -0,0 +1,2356 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.137, + 0.13, + 0.834, + 0.177 + ], + "angle": 0, + "content": "MasaCtrl: Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing" + }, + { + "type": "text", + "bbox": [ + 0.088, + 0.211, + 0.908, + 0.282 + ], + "angle": 0, + "content": "Mingdeng Cao\\(^{1,2*}\\) Xintao Wang\\(^{2}\\) Zhongang Qi\\(^{2}\\) Ying Shan\\(^{2}\\) Xiaohu Qie\\(^{2}\\) Yinqiang Zheng\\(^{1}\\) \n\\(^{1}\\)The University of Tokyo \\({}^{2}\\)ARC Lab, Tencent PCG \nhttps://github.com/TencentARC/MasaCtrl" + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.293, + 0.337, + 0.395 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.098, + 0.397, + 0.191, + 0.41 + ], + "angle": 0, + "content": "Input real image" + }, + { + "type": "image", + "bbox": [ + 0.34, + 0.293, + 0.598, + 0.395 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.375, + 0.397, + 0.562, + 0.41 + ], + "angle": 0, + "content": "\"A sitting boy\" \\(\\rightarrow\\) \"... standing ...\"" + }, + { + "type": "image", + "bbox": [ + 0.601, + 0.293, + 0.862, + 0.395 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.618, + 0.397, + 0.859, + 0.41 + ], + "angle": 0, + "content": "Input real image \"... , giving a thumbs up\"" + }, + { + "type": "image", + "bbox": [ + 0.079, + 0.413, + 0.338, + 0.515 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.116, + 0.516, + 0.3, + 0.528 + ], + "angle": 0, + "content": "\"Elon Musk\" \\(\\rightarrow\\) \"... side view ...\"" + }, + { + "type": "image", + "bbox": [ + 0.34, + 0.413, + 0.598, + 0.515 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.39, + 0.516, + 0.546, + 0.529 + ], + "angle": 0, + "content": "\"An apple\" \\(\\rightarrow\\) \"Two apples\"" + }, + { + "type": "image", + "bbox": [ + 0.601, + 0.413, + 0.862, + 0.515 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.612, + 0.516, + 0.849, + 0.53 + ], + "angle": 0, + "content": "\"A standing bird\" \\(\\rightarrow\\) \"..., spreading wings\"" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.54, + 0.893, + 0.587 + ], + "angle": 0, + "content": "Figure 1: Our method MasaCtrl can perform text-based non-rigid image synthesis and real image editing without fine-tuning. Meanwhile, our method can be easily integrated into controllable diffusion models, like T2I-Adapter [17] or ControlNet [45], to perform more consistent and faithful synthesis and editing (last column)." + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.599, + 0.314, + 0.615 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.632, + 0.473, + 0.875 + ], + "angle": 0, + "content": "Despite the success in large-scale text-to-image generation and text-conditioned image editing, existing methods still struggle to produce consistent generation and editing results. For example, generation approaches usually fail to synthesize multiple images of the same objects/characters but with different views or poses. Meanwhile, existing editing methods either fail to achieve effective complex non-rigid editing while maintaining the overall textures and identity, or require time-consuming fine-tuning to capture the image-specific appearance. In this paper, we develop MasaCtrl, a tuning-free method to achieve consistent image generation and complex non-rigid image editing simultaneously. Specifically, MasaCtrl converts existing self-attention in diffusion models into mutual self-attention, so that it can query correlated local contents and textures from source images for consistency. To further alleviate the query" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.601, + 0.893, + 0.692 + ], + "angle": 0, + "content": "confusion between foreground and background, we propose a mask-guided mutual self-attention strategy, where the mask can be easily extracted from the cross-attention maps. Extensive experiments show that the proposed MasaCtrl can produce impressive results in both consistent image generation and complex non-rigid real image editing." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.737, + 0.633, + 0.753 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Recent advances in text-to-image (T2I) generation [25, 19, 41, 24, 27] have achieved great success. Those large-scale T2I models, such as Stable Diffusion [27], can generate diverse and high-quality images conforming to given text prompts. When leveraging the T2I models, we can also perform promising text-conditioned image editing [19, 10, 35, 21]. However, there is still a large gap between our needs and existing methods in terms of consistent generation and editing." + }, + { + "type": "page_footnote", + "bbox": [ + 0.101, + 0.887, + 0.424, + 0.901 + ], + "angle": 0, + "content": "*Work done during an internship at ARC Lab, Tencent PCG." + }, + { + "type": "footer", + "bbox": [ + 0.479, + 0.925, + 0.521, + 0.937 + ], + "angle": 0, + "content": "22560" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.244 + ], + "angle": 0, + "content": "For the text-to-image generation, we usually want to generate several images of the same objects/characters but with different views or complex non-rigid variances (e.g., the changes of posture). Such capabilities are urgently needed for creating comic books and generating short videos using existing powerful T2I image models. However, this requirement is highly challenging. Even if we fix the input random noise and use very similar prompts (e.g., 'a sitting cat' vs. 'a laying cat' shown in Fig. 2), the generated images vary in both structures and identity." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.247, + 0.473, + 0.489 + ], + "angle": 0, + "content": "For text-conditioned image editing, existing methods [10, 35, 21] achieve impressive editing effects in image translation, stylization, and appearance replacement while keeping the input structure and scene layout unchanged. However, those methods usually fail to change poses or views while maintaining the overall textures and identity, leading to inconsistent editing results. The latter editing way is a more complicated non-rigid editing for practical use. Imagic [12] is then proposed to address this challenge. It allows complex non-rigid edits while preserving its original characteristics. It can make a standing dog sit down, cause a bird to spread its wings, etc. Nevertheless, it requires fine-tuning the entire T2I diffusion model and optimizing the textual embedding to capture the image-specific appearance for each edit, which is time-consuming and impractical for real-world applications." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.494, + 0.473, + 0.902 + ], + "angle": 0, + "content": "In this paper, we aim to develop a tuning-free method to address the above challenges, enabling a more consistent generation of multiple images and complex non-rigid editing without fine-tuning. The core challenge is how to keep consistent. Unlike previous works [10, 21, 3] that usually operate on cross-attention in T2I models, we propose to convert existing self-attention to mutual self-attention, so that it can query correlated local structures and textures from a source image for consistency. Specifically, we first generate an image from a random (or inverted a real image) noise, resulting in the denoising process (DP1) for the source image synthesis. In the new denoising process (DP2) of generating a new image or editing an existing one, we can use the Query features in DP2 self-attention to query the corresponding Key and Value features in DP1 self-attention. In other words, we transform the existing self-attention into 'cross-attention', where the crossing operation happens in the self-attention of two related denoising processes, rather than between the U-Net features and text embeddings. We call this 'crossing self-attention as mutual self-attention. However, directly applying this strategy can only generate images almost identical to the source image and cannot comply with the target text prompt (as analyzed in Fig. 9). Thus we further control the denoising timestep and the layer position in U-Net for performing mutual self-attention to achieve consistent synthesis and editing. More analyses are in Sec. 4.1 and Sec. 5.5. In this" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.091, + 0.633, + 0.19 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.532, + 0.193, + 0.603, + 0.205 + ], + "angle": 0, + "content": "\"...sitting...\"" + }, + { + "type": "image", + "bbox": [ + 0.633, + 0.091, + 0.761, + 0.19 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.661, + 0.193, + 0.732, + 0.205 + ], + "angle": 0, + "content": "...laying..." + }, + { + "type": "image", + "bbox": [ + 0.763, + 0.091, + 0.89, + 0.19 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.771, + 0.193, + 0.882, + 0.205 + ], + "angle": 0, + "content": "...laying...\" (Ours)" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.207, + 0.633, + 0.306 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.548, + 0.31, + 0.588, + 0.32 + ], + "angle": 0, + "content": "Source" + }, + { + "type": "image", + "bbox": [ + 0.633, + 0.207, + 0.761, + 0.306 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.645, + 0.31, + 0.75, + 0.321 + ], + "angle": 0, + "content": "w/o mask guidance" + }, + { + "type": "image", + "bbox": [ + 0.763, + 0.207, + 0.89, + 0.306 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.771, + 0.31, + 0.881, + 0.321 + ], + "angle": 0, + "content": "with mask guidance" + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.334, + 0.892, + 0.395 + ], + "angle": 0, + "content": "Figure 2: First row: images synthesized from fixed random seed (middle, changed identity) and our method (right, maintained identity). Second row: image synthesized without mask guidance (middle) and with mask guidance (right)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.412, + 0.892, + 0.502 + ], + "angle": 0, + "content": "way, we can use contents in the source image as the generation material to better maintain the texture and identity. Meanwhile, its structure, pose, and non-rigid variances can be controlled by target text prompt, and guided by recent controllable T2I-Adapters [17] or ControlNet [45]. Fig. 1 shows some synthesis and editing examples." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.505, + 0.893, + 0.747 + ], + "angle": 0, + "content": "The proposed mutual self-attention control can work well for images with disentangled foreground and background, but may fail in the synthesis and editing process where the foreground and background have similar patterns and colors. In these cases, mutual self-attention tends to confuse the foreground and background, leading to a messy result (2nd row in Fig. 2). To address this problem, we further propose a mask-guided mutual self-attention. Specifically, we first utilize the cross attention in T2I diffusion models to extract a mask associated with the main object in the image. This mask can successfully separate foreground and background, and restrict the target foreground/background features to query only foreground/background features of the source image, respectively. Such an operation can effectively alleviate the query confusion between the foreground and background." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.895, + 0.902 + ], + "angle": 0, + "content": "Our contributions can be summarized as follows. 1) We propose a tuning-free method, namely, MasaCtrl, to simultaneously achieve consistent image synthesis and complex non-rigid image editing. 2) An effective mutual self-attention mechanism with delicate designs is proposed to change pose, view, structures, and non-rigid variances while maintaining the characteristics, texture, and identity. 3) To alleviate the query confusion between foreground and background, we further propose a masked-guided mutual self-attention, where the mask can be easily computed from the" + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.518, + 0.937 + ], + "angle": 0, + "content": "22561" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.138 + ], + "angle": 0, + "content": "cross-attentions. 4) Experimental results have shown the effectiveness of our proposed MasaCtrl in both consistent image generation and complex non-rigid real image editing." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.152, + 0.22, + 0.167 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.178, + 0.313, + 0.194 + ], + "angle": 0, + "content": "2.1. Text-to-Image Generation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.201, + 0.473, + 0.55 + ], + "angle": 0, + "content": "Early image generation methods conditioned on text description mainly based on GANs [26, 43, 44, 39, 14, 2, 46, 40, 42, 34], due to their powerful capability of high-fidelity image synthesis. These models try to align the text descriptions and synthesized image contents via multimodal vision-language learning and have achieved cheerful synthesis results on domain-specific datasets. Text-to-image generation with auto-regressive and diffusion models has obtained impressive diversity results. DALL-E [25], CogView [6] and Parti [41], large-scale text-to-image models trained with a large amount of data, enable generating images from open-domain text descriptions. However, the auto-regressive generation nature leads to the slow generation process defect. Most recently, diffusion models [32, 11, 20, 5] have shown superior generative power and achieved state-of-the-art synthesis results in terms of image quality and diversity than previous GAN-based and auto-regressive image generation models. By conditioning the text prompt into the diffusion model, various text-to-image diffusion models GLIDE [19], VQ-Diffusion [8], LDM [27], DALL-E 2 [24], and Imagen [30] have been developed. They can synthesize high-quality images that highly comply with the given text description." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.56, + 0.323, + 0.577 + ], + "angle": 0, + "content": "2.2. Text-guided Image Editing." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.584, + 0.47, + 0.75 + ], + "angle": 0, + "content": "Text-guided image editing is a challenging task that aims to manipulate images according to natural language descriptions. Previous methods based on generative adversarial networks (GANs) [18, 15, 38, 22] have achieved some success on domain-specific datasets (e.g., face datasets), but they have limited applicability and generality. A recent approach based on auto-regressive models, VQGAN-CLIP [4], combines VQGAN [7] and CLIP [23] to produce high-quality images and precise edits with diverse and controllable results. However, this approach suffers from slow generation speed and high computational cost." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Different from previous methods based on GANs or auto-regressive models, diffusion models offer a fast and efficient way to synthesize and edit images conditioned on text prompts. However, existing diffusion-based methods have some limitations regarding local and global editing. For example, the works [19, 1] require extra masks to edit local regions of the image; [13] can edit global aspects of the image by changing the text prompt directly, but cannot modify local details; [10, 35] use cross-attention or spatial features to edit both global and local aspects of the image" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.895, + 0.304 + ], + "angle": 0, + "content": "by changing the text prompt directly. Still, they tend to preserve the original layout of the source image and fail to handle non-rigid transformations (e.g., changing object pose). In contrast, we propose a novel approach that leverages the self-attention mechanism to achieve consistent and complex non-rigid image synthesis and editing. Our approach can modify various object attributes (e.g., pose, shape) by changing the text prompt accordingly. The most related work to ours is Imagic [12], which also enables various prompt-based non-rigid image editing. However, unlike our approach can edit images on the fly, Imagic requires careful optimization of the textual embedding and fine-tuning of the model, which is time-consuming and unfriendly for ordinary users." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.319, + 0.64, + 0.335 + ], + "angle": 0, + "content": "3. Preliminaries" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.344, + 0.724, + 0.36 + ], + "angle": 0, + "content": "3.1. Latent Diffusion Models" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.368, + 0.895, + 0.566 + ], + "angle": 0, + "content": "Diffusion models [11, 31, 20] are generative models that can synthesize desired data samples from Gaussian noise via iterative denoising. Our method is based on the recent state-of-the-art text-conditioned model Stable Diffusion (SD) [27], which performs the diffusion-denoising process in the latent rather than image space. Specifically, a pretrained image autoencoder first encodes the image \\( x \\) into latent representations \\( z \\). Then the denoising network \\( \\epsilon_{\\theta} \\) (a time-conditional U-Net [28]) is trained in this latent space. After being trained, we can sample a random noise \\( z_{T} \\sim \\mathcal{N}(0,1) \\) and perform the latent denoising process. The denoised latent representation \\( z_{0} \\) can be decoded into an image using the pretrained autoencoder." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.576, + 0.851, + 0.592 + ], + "angle": 0, + "content": "3.2. Attention Mechanism in Stable Diffusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.6, + 0.894, + 0.751 + ], + "angle": 0, + "content": "The denoising U-Net \\(\\epsilon_{\\theta}\\) in the SD model, consists of a series of basic blocks, and each basic block contains a residual block [9], a self-attention module, and a cross-attention [36] module. At denoising step \\(t\\), the features from the previous \\((l - 1)\\)-th basic block first pass through the residual block to generate intermediate features \\(f_{t}^{l}\\); then they are reorganized by the self-attention layer, and receive textual information from the text prompt \\(P\\) by the following cross-attention layer. The attention mechanism can be formulated as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.556, + 0.761, + 0.892, + 0.796 + ], + "angle": 0, + "content": "\\[\n\\operatorname {A t t e n t i o n} (Q, K, V) = \\operatorname {S o f t m a x} \\left(\\frac {Q K ^ {T}}{\\sqrt {d}}\\right) V, \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.806, + 0.894, + 0.903 + ], + "angle": 0, + "content": "where \\( Q \\) is the query features projected from the spatial features, and \\( K, V \\) are the key and value features projected from the spatial features (in self-attention layers) or the textual embedding (in cross-attention layers) with corresponding projection matrices. \\( A = \\operatorname{Softmax}\\left(\\frac{QK^T}{\\sqrt{d}}\\right) \\) is the attention map used to aggregate the value \\( V \\)." + }, + { + "type": "footer", + "bbox": [ + 0.479, + 0.926, + 0.521, + 0.938 + ], + "angle": 0, + "content": "22562" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.089, + 0.885, + 0.371 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.381, + 0.895, + 0.444 + ], + "angle": 0, + "content": "Figure 3: Pipeline of the proposed MasaCtrl. Our method tries to perform complex non-rigid image editing and synthesize content-consistent images. The source image is either real or synthesized with source text prompt \\( P_{s} \\). During the denoising process for image synthesis, we convert the self-attention into mutual self-attention to query image contents from source image \\( I_{s} \\), so that we can synthesize content-consist images under the modified target prompt \\( P \\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.469, + 0.473, + 0.759 + ], + "angle": 0, + "content": "These attention layers in the SD model contain much information for the overall structure/layout and content formation of the synthesized image [10, 35]. The internal cross-attention maps are high-dimensional tensors that bind the spatial pixels and textual embedding [10], and they are explored for image editing [10] and faithful image synthesis [3]. In addition, the features in the self-attention layer are employed as plug-and-play features to be injected into specified U-Net layers to perform image translation. However, these controls cannot perform non-rigid editing (e.g., pose change) since they maintain the semantic layout and structures. Inspired by the phenomenon that performing self-attention across batches can generate similar image contents, which is also observed in Tune-A-Video [37], we adapt the self-attention mechanism in the T2I model to query contents from source images with delicate designs. Thus we can perform consistent synthesis and non-rigid editing that change the layout and structure of the source image while preserving image contents." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.77, + 0.466, + 0.788 + ], + "angle": 0, + "content": "4. Tuning-Free Mutual Self-Attention Control" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.796, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Given a source image \\( I_{s} \\) and the corresponding text prompt \\( P_{s} \\), our goal is to synthesize the desired image \\( I \\) that complies with the target edited text prompt \\( P \\) (directly modified from \\( P_{s} \\)). Note that the edited target image \\( I \\) is spatially edited from \\( I_{s} \\) and should preserve the object contents (e.g., textures and identity) in \\( I_{s} \\). For instance, consider a photo (corresponding to \\( P_{s} \\)) where a dog is sitting," + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.469, + 0.892, + 0.514 + ], + "angle": 0, + "content": "and we want the dog to be in the running pose with the edited text prompt \\( P \\) that adds the 'running' into the source prompt \\( P_{s} \\) (see Fig. 3)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.516, + 0.893, + 0.742 + ], + "angle": 0, + "content": "Our core idea is to combine the semantic layout synthesized with the target prompt \\( P \\) and the contents in the source image \\( I_{s} \\) to synthesize the desired image \\( I \\). To achieve so, we propose MasaCtrl, which adapts the self-attention mechanism in the SD model into a crossing one to query semantically similar contents from the source image. Consequently, the target image \\( I \\) can be synthesized by querying the contents from \\( I_{s} \\) with the modified self-attention mechanism during the denoising process. We can achieve so for the following reasons: 1) the image layout is formed in the early denoising steps (shown in Fig. 4(a)); 2) in addition, as shown in Fig. 4(b), the encoded query features in the self-attention layer are semantically corresponded (e.g., the horses are in the same color), thus one can query content information from another." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.744, + 0.895, + 0.837 + ], + "angle": 0, + "content": "The overall architecture of the proposed pipeline to perform synthesis and editing is shown in Fig. 3, and the algorithm is summarized in Alg. 1. The input source image \\( I_{s} \\) is either a real image or a generated one from the SD model with text prompt \\( P_{s} \\). During each denoising step \\( t \\) of synthesizing target image \\( I \\), we assemble the inputs of" + }, + { + "type": "page_footnote", + "bbox": [ + 0.499, + 0.851, + 0.895, + 0.901 + ], + "angle": 0, + "content": "1When \\( I_{s} \\) is a real image, we set the text prompt \\( P_{s} \\) as null and utilize the deterministic DDIM inversion [31] to obtain the initial noise map. When \\( I_{s} \\) is an image synthesized with prompt \\( P_{s} \\), the initial noise map is the same as the one used to synthesize \\( I_{s} \\)." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.925, + 0.521, + 0.937 + ], + "angle": 0, + "content": "22563" + } + ], + [ + { + "type": "code_caption", + "bbox": [ + 0.078, + 0.091, + 0.47, + 0.119 + ], + "angle": 0, + "content": "Algorithm 1 MasaCtrl: Tuning-Free Mutual Self-Attention Control" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.121, + 0.468, + 0.152 + ], + "angle": 0, + "content": "Input: A source prompt \\( P_{s} \\), a modified prompt \\( P \\), the source and target initial latent noise maps \\( z_{T}^{s} \\) and \\( z_{T} \\)." + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.152, + 0.468, + 0.18 + ], + "angle": 0, + "content": "Output: Latent map \\( z_0^s \\), edited latent map \\( z_0 \\) corresponding to \\( P_s \\) and \\( P \\)." + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.184, + 0.279, + 0.198 + ], + "angle": 0, + "content": "1: for \\( t = T, T - 1, \\ldots, 1 \\) do" + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.199, + 0.345, + 0.214 + ], + "angle": 0, + "content": "2: \\(\\epsilon_s, \\{Q_s, K_s, V_s\\} \\gets \\epsilon_\\theta(z_t^s, P_s, t)\\);" + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.215, + 0.283, + 0.229 + ], + "angle": 0, + "content": "3: \\(z_{t - 1}^{s}\\gets \\mathrm{Sample}(z_{t}^{s},\\epsilon_{s})\\)" + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.229, + 0.299, + 0.244 + ], + "angle": 0, + "content": "4: \\(\\{Q,K,V\\} \\gets \\epsilon_{\\theta}(z_t,P,t)\\)" + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.244, + 0.462, + 0.26 + ], + "angle": 0, + "content": "5: \\(\\{Q^{*},K^{*},V^{*}\\} \\leftarrow\\) EDIT(\\(\\{Q,K,V\\},\\{Q_{s},K_{s},V_{s}\\}\\));" + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.26, + 0.332, + 0.275 + ], + "angle": 0, + "content": "6: \\(\\epsilon = \\epsilon_{\\theta}(z_t,P,t;\\{Q^*,K^*,V^*\\})\\)" + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.276, + 0.274, + 0.29 + ], + "angle": 0, + "content": "7: \\(z_{t - 1}\\gets \\mathrm{Sample}(z_t,\\epsilon);\\)" + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.291, + 0.16, + 0.303 + ], + "angle": 0, + "content": "8: end for" + }, + { + "type": "list", + "bbox": [ + 0.089, + 0.184, + 0.462, + 0.303 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.308, + 0.172, + 0.322 + ], + "angle": 0, + "content": "Return \\(z_0^s, z_0\\)" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.352, + 0.468, + 0.426 + ], + "angle": 0, + "content": "the self-attention by 1) keeping the current Query features \\( Q \\) unchanged, and 2) obtaining the Key and Value features \\( K_{s} \\), \\( V_{s} \\) from the self-attention layer in the process of synthesizing source image \\( I_{s} \\). We dub this strategy mutual self-attention, and more details are in Sec. 4.1." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.428, + 0.468, + 0.547 + ], + "angle": 0, + "content": "Meanwhile, we also observe the edited image often suffers from the problem of confusion between the foreground objects and background. Thus, we propose a mask-aware mutual self-attention strategy guided by the masks obtained from the cross-attention mechanism. The object mask is automatically generated from the cross-attention maps of the text token associated with the foreground object. Please refer to Sec. 4.2 for more details." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.549, + 0.468, + 0.64 + ], + "angle": 0, + "content": "In addition, since the edited prompt \\( P \\) may not yield desired spatial layouts due to the inner limitations of the SD model, MasaCtrl can be easily integrated into existing controllable image synthesis method (e.g., T2I-Adapter [17] and ControlNet [45]) for more faithful non-rigid image editing. Please refer to Sec. 4.3 for more details." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.65, + 0.283, + 0.665 + ], + "angle": 0, + "content": "4.1. Mutual Self-Attention" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.674, + 0.468, + 0.794 + ], + "angle": 0, + "content": "As shown in the left part of Fig. 5(a), at denoising step \\( t \\) and layer \\( l \\), the query features are defined as the projected query features \\( Q^l \\) in the self-attention module, and the content features are the key features \\( K_s^l \\) and value features \\( V_s^l \\) from the corresponding self-attention layer in the process of reconstructing the source image \\( I_s \\). After that, we perform attention according to Eq. 1 to aggregate the contents from the source image." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.796, + 0.468, + 0.901 + ], + "angle": 0, + "content": "However, intuitively performing such attention on all layers among all denoising steps will result in a failed image \\(I\\) that is nearly the same as the reconstructed image \\(I_{s}\\). We argue the reason is that performing self-attention control in the early steps can disrupt the layout formation of the target image. In the premature denoising steps, the target image layout has not yet been formed (shown in Fig. 4(a))." + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.09, + 0.888, + 0.187 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.569, + 0.186, + 0.839, + 0.199 + ], + "angle": 0, + "content": "(a) Intermediate results in denoising process" + }, + { + "type": "image", + "bbox": [ + 0.526, + 0.2, + 0.888, + 0.313 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.611, + 0.314, + 0.8, + 0.328 + ], + "angle": 0, + "content": "(b) Query feature visualization" + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.339, + 0.892, + 0.401 + ], + "angle": 0, + "content": "Figure 4: (a) The intermediate results during the iterative denoising process, and (b) visualization of the projected Query features \\( Q \\) in the self-attention layers of the U-Net at the 15th sampling step." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.429, + 0.892, + 0.504 + ], + "angle": 0, + "content": "We further observe the Query features in the shallow layers of U-Net (e.g., encoder part) cannot obtain clear layout and structure corresponding to the modified prompt (shown in Fig. 4(b)). Thus we cannot obtain the image with the desired spatial layout." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.509, + 0.892, + 0.644 + ], + "angle": 0, + "content": "Therefore, we propose to control the mutual self-attention only in the decoder part of the \\(U\\)-Net after several denoising steps, due to the formed clear target image layout and semantically similar features (see Fig. 4). We can change the original layout into the target one with edited prompt \\(P\\) and keep the main objects unchanged with proper starting denoising step \\(S\\) and layer \\(L\\) for synthesis and editing. Thus the EDIT function in Alg. 1 can be formulated as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.503, + 0.662, + 0.891, + 0.715 + ], + "angle": 0, + "content": "\\[\n\\operatorname {E D I T} := \\left\\{ \\begin{array}{l l} \\left\\{Q, K _ {s}, V _ {s} \\right\\}, & \\text {i f} \\quad T - t > S \\quad \\text {a n d} \\quad l > L, \\\\ \\left\\{Q, K, V \\right\\}, & \\text {o t h e r w i s e ,} \\end{array} \\right. \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.715, + 0.89, + 0.746 + ], + "angle": 0, + "content": "where \\( S \\) and \\( L \\) are the timestep and layer index to start attention control, respectively. \\( T \\) is the total denoising steps." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.892, + 0.901 + ], + "angle": 0, + "content": "In the early steps, the composition and shape of the object can be roughly generated, complying with the target prompt \\( P \\). Then the content information from the source image \\( I_{s} \\) is queried by the mutual self-attention mechanism to fill the generated layout of target image \\( I \\). After iterative denoising, we can obtain the synthesized image with similar contents in the source image and structure of \\( I^{*} \\) that complied with the input prompt. Note that our algorithm does not require fine-tuning or optimization, bringing many conveniences for ordinary users for content creation." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.926, + 0.519, + 0.938 + ], + "angle": 0, + "content": "22564" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.089, + 0.468, + 0.232 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.176, + 0.234, + 0.375, + 0.248 + ], + "angle": 0, + "content": "(a) Mutual self-attention control" + }, + { + "type": "image", + "bbox": [ + 0.084, + 0.254, + 0.465, + 0.404 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.131, + 0.406, + 0.416, + 0.42 + ], + "angle": 0, + "content": "(b) Mask extraction from cross-attention maps" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.43, + 0.47, + 0.492 + ], + "angle": 0, + "content": "Figure 5: (a) The mutual self-attention mechanism and control strategy in the decoder part of denoising U-Net to query contents from the source image; and (b) mask extraction strategy from cross-attention maps." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.526, + 0.393, + 0.541 + ], + "angle": 0, + "content": "4.2. Mask-Guided Mutual Self-Attention" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.559, + 0.47, + 0.726 + ], + "angle": 0, + "content": "We also observed the above synthesis/editing would fail when the object and background are too similar to be confused. One feasible way to tackle this problem is to segment the image into the foreground and background parts and query contents only from the corresponding parts. Inspired by previous work [10, 33], the cross-attention maps correlating to the prompt tokens contain most information of the shape and structure. Therefore, we utilize the semantic cross-attention maps to create a mask to distinguish the foreground and background in both source and target images \\( I_{s} \\) and \\( I \\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Specifically, at step \\( t \\), we first perform forward passes with source prompt \\( P_{s} \\) and edited prompt \\( P \\), respectively, to generate intermediate cross-attention maps. Then we average the cross-attention maps across all heads and layers with the spatial resolution \\( 16 \\times 16 \\). The resulting cross-attention maps are denoted as \\( A_{t}^{c} \\in \\mathbb{R}^{16 \\times 16 \\times N} \\), where \\( N \\) is the number of the textual tokens. We then obtain the averaged cross-attention map for the token correlated to the foreground object. We denote \\( M_{s} \\) and \\( M \\) as masks extracted for the foreground objects in \\( I_{s} \\) and \\( I \\), respectively. With these masks, we can restrict the object in \\( I \\) to query" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.859, + 0.107 + ], + "angle": 0, + "content": "contents information only from the object region in \\(I_{s}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.57, + 0.111, + 0.892, + 0.129 + ], + "angle": 0, + "content": "\\[\nf _ {o} ^ {l} = \\text {A t t e n t i o n} \\left(Q ^ {l}, K _ {s} ^ {l}, V _ {s} ^ {l}; M _ {s}\\right), \\tag {3}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.572, + 0.133, + 0.892, + 0.15 + ], + "angle": 0, + "content": "\\[\nf _ {b} ^ {l} = \\text {A t t e n t i o n} \\left(Q ^ {l}, K _ {s} ^ {l}, V _ {s} ^ {l}; 1 - M _ {s}\\right), \\tag {4}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.572, + 0.153, + 0.892, + 0.171 + ], + "angle": 0, + "content": "\\[\n\\bar {f} ^ {l} = f _ {o} ^ {l} * M + f _ {b} ^ {l} * (1 - M), \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.178, + 0.892, + 0.253 + ], + "angle": 0, + "content": "where \\(\\bar{f}^l\\) is the final attention output. The object and background regions in the target image query the contents from corresponding restricted areas rather than all source image features. Note that this strategy is optional and used when confusion occurs." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.261, + 0.88, + 0.277 + ], + "angle": 0, + "content": "4.3. Integration to Controllable Diffusion Models" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.284, + 0.892, + 0.435 + ], + "angle": 0, + "content": "Our method can be integrated into existing controllable diffusion models (e.g., T2I-Adapter [17] and ControlNet [45]) for more faithful non-rigid image synthesis and editing. These methods enable the original Stable Diffusion model to be more controllable (e.g., pose, sketch, segmentation map) in image synthesis. Thus we can use them to synthesize images with desired poses and shapes. Since our method can query image contents (e.g., textures) from a reference image, we can easily integrate our approach into these models to generate more consistent images." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.435, + 0.892, + 0.526 + ], + "angle": 0, + "content": "Specifically, we follow the same process depicted in Alg. 1, and the desired target image synthesis process is changed from the original SD model to using these controllable models instead. In the following experiment section, we demonstrate the effectiveness of such a combination that can synthesize images consistently." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.534, + 0.634, + 0.551 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.559, + 0.892, + 0.77 + ], + "angle": 0, + "content": "Setup. We apply the proposed method to the state-of-the-art text-to-image Stable Diffusion [27] model with publicly available checkpoints v1.4. We also validate the proposed method on the pre-trained anime-style model Anything-V4. Meanwhile, we perform editing on both synthetic images and real images. For real image editing, we first invert the image into the initial noise map with DDIM deterministic inversion [31]. Note that we set the starting noise map the same for source prompt \\( P_{s} \\) and the desired prompt \\( P \\) unless otherwise specified. During sampling, we perform DDIM sampling [31] with 50 denoising steps, and the classifier-free guidance is set to 7.5. The step and layer to start attention control is set to \\( S = 4 \\), \\( L = 10 \\) as default. Note that it may be changed for specific checkpoints." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.774, + 0.803, + 0.789 + ], + "angle": 0, + "content": "5.1. Comparisons with Previous Works" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.793, + 0.892, + 0.869 + ], + "angle": 0, + "content": "We mainly compare the proposed tuning-free method to the current prompt-based editing methods with diffusion models, including tuning-free methods SDEdit [16], P2P [10], PnP [35], and Imagc [12]. We use their open-sourced codes to produce the editing results2." + }, + { + "type": "page_footnote", + "bbox": [ + 0.5, + 0.875, + 0.892, + 0.9 + ], + "angle": 0, + "content": "2We adopt the community version of Imagic as the official source code is not open-sourced" + }, + { + "type": "footer", + "bbox": [ + 0.479, + 0.926, + 0.519, + 0.938 + ], + "angle": 0, + "content": "22565" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.087, + 0.891, + 0.471 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.482, + 0.897, + 0.561 + ], + "angle": 0, + "content": "Figure 6: Editing results of different methods on the synthetic images (a) and real images (b). Our method enables consistent synthesis by combining the layout of the target prompt and the contents of source generated image. From left to right: the source generated source image with source prompt, synthesis results with the proposed MasaCtrl method, synthesis results from target prompt with the same random noise of source image, synthesis/editing results with existing methods P2P [10], SDEdit [16], PnP [35], and Imagc [12]." + }, + { + "type": "image", + "bbox": [ + 0.078, + 0.57, + 0.473, + 0.717 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.728, + 0.895, + 0.761 + ], + "angle": 0, + "content": "Figure 7: Editing results of synthetic images (left part) and real images (right part) with MasaCtrl integrated into T2I-Adapter [17]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.785, + 0.473, + 0.892 + ], + "angle": 0, + "content": "Qualitative comparison. The consistent synthesis results are shown in Fig. 6(a). By directly modifying the text prompt, our method can synthesize content-consistent images. These synthesized images (1) contain contents (foreground objects and background) that are highly similar to those in the generated source images (first column of Fig. 6) and (2) highly comply with the target prompt \\( P \\) (third col" + }, + { + "type": "image", + "bbox": [ + 0.498, + 0.57, + 0.892, + 0.717 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.785, + 0.895, + 0.892 + ], + "angle": 0, + "content": "unn of Fig. 6). While existing methods fail to synthesize desired images, either conforming to the target text prompt or inconsistent with the source images. Our method also achieves promising results in editing real images shown in Fig. 6(b). The edited image is consistent with the target prompt and maintains source image content. These results demonstrate the effectiveness of the proposed method." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.926, + 0.521, + 0.938 + ], + "angle": 0, + "content": "22566" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.09, + 0.894, + 0.212 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.139, + 0.221, + 0.828, + 0.236 + ], + "angle": 0, + "content": "Figure 8: Video synthesis results of proposed MasaCtrl with T2I-Adapter [17] (with key-pose guidance)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.263, + 0.47, + 0.475 + ], + "angle": 0, + "content": "Quantitative comparison. For quantitative evaluation, we used 20 different source images (10 are synthetic and 10 are real) and edited them with P2P, PnP, Imagic, and MasaCtrl. We evaluate the text-alignment between the target prompt and edited image, and the image-alignment between the source and edited images in the CLIP feature space. Tab. 1 shows that MasaCtrl can synthesize images that comply with the target prompt while maintaining content consistency more than other methods. We also conducted a user study and collected 700 answers from professional participants. As shown in the preference column of Tab. 1, \\(73.5\\%\\) of participants preferred our method. Meanwhile, our method is efficient since no fine-tuning and optimization are required." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.476, + 0.47, + 0.688 + ], + "angle": 0, + "content": "We further analyze the reasons attributed to the failure of existing methods (i.e., P2P, SDEdit, and PnP). These methods try to keep the original layout or object shape and pose unchanged by leveraging the layout information encoded in the cross-attention maps (P2P), features (PnP), and original input images (SDEdit). Meanwhile, the contents in the formed image mainly come from the encoded text embedding. As a result, the images synthesized by these methods have similar layouts to the source image but have different contents. In our proposed method MasaCtrl, the structure of the desired image is first determined by the former iteration in the denoising process, and the final image is formed by obtaining the image content from the source image. Thus we can perform various types of non-rigid image editing." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.694, + 0.31, + 0.71 + ], + "angle": 0, + "content": "5.2. Results with T2I-Adapter" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.714, + 0.468, + 0.805 + ], + "angle": 0, + "content": "The initial layout controlled by modifying the text prompt usually fails due to the inherent drawbacks of the Stable Diffusion model. Therefore, we further integrate our method into existing controllable synthesis pipelines to obtain stable synthesis and editing results. The synthetic and real image editing results of MasaCtrl with T2I-" + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.81, + 0.466, + 0.871 + ], + "angle": 0, + "content": "
MethodText-alignmentImage-alignmentPreferenceRuntime
P2P [10]0.26910.87933.0%15s
PnP [35]0.25890.89022.5%60s
Imagic [12]0.26880.915921.0%14min
Ours0.27930.928673.5%16s
" + }, + { + "type": "table_caption", + "bbox": [ + 0.128, + 0.882, + 0.418, + 0.896 + ], + "angle": 0, + "content": "Table 1: Quantitative and user study results." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.263, + 0.892, + 0.475 + ], + "angle": 0, + "content": "Adapter [17] are shown in Fig. 7. We see that T2I-Adapter can generate an image with desired target layout, yet with different contents in the source image. In contrast, our method can effectively combine the layout synthesized by T2I-Adapter with the target prompt and the contents in the source image. Therefore, more faithful and fine-grained synthesis and editing results can be obtained. Note that we may change the attention strategy of starting denoising step \\( S \\) and U-Net layer \\( L \\) to obtain faithful results (\\( S = 2 \\), \\( L = 8 \\) in our experiment), since the target layout is strongly controlled by extra guidance. Therefore, we can perform attention control in early steps and layers to query faithful contents in the source image, refer to the ablation study Sec. 5.5 for the analysis." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.483, + 0.753, + 0.498 + ], + "angle": 0, + "content": "5.3. Robustness to Other Models" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.507, + 0.892, + 0.598 + ], + "angle": 0, + "content": "Our method can be applied to other versions of Stable Diffusion models (e.g., v1.5), domain-specific models (e.g., the amine-style model Anything-v4), and customized models (e.g., models fine-tuned with DreamBooth [29]) to achieve consistent image synthesis and editing. Please refer to the supplementary materials for the visual results." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.606, + 0.757, + 0.622 + ], + "angle": 0, + "content": "5.4. Extension to Video Synthesis" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.629, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Although our method is designed for consistent image synthesis and editing, we can easily extend our method for the video synthesis task using T2I-Adapter and ControlNet with a series of dense temporal-coherent guidance (e.g., pose, edge, depth). Specifically, we first generate a source image with the prompt \\( P_{s} \\) and guidance as the canonical frame (shown in the first column of Fig. 8). The other frames are synthesized separately with MasaCtrl. Then all the synthesized frames can be concatenated into a video since they are content-consistent with the source frame. Fig. 8 shows the video synthesis results with coherent dense guidance. The proposed method successfully synthesizes consistent frames with highly similar content (more video results are available on the project page and supplementary materials). However, our method can only animate the foreground objects (such as the bear in Fig. 8) and hardly bring the background alive. Therefore, video-based approaches still need to be explored since the current MasaCtrl has" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.926, + 0.518, + 0.938 + ], + "angle": 0, + "content": "22567" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.088, + 0.089, + 0.36, + 0.201 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.37, + 0.089, + 0.888, + 0.203 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.251, + 0.206, + 0.757, + 0.221 + ], + "angle": 0, + "content": "(a) Results of mutual self-attention control starting from different denoising steps" + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.223, + 0.891, + 0.337 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.276, + 0.34, + 0.697, + 0.355 + ], + "angle": 0, + "content": "(b) Results of mutual self-attention control in different U-Net layers" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.365, + 0.893, + 0.426 + ], + "angle": 0, + "content": "Figure 9: Results of mutual self-attention control in different denoising steps (a) and different U-Net layers (b). We see that only performing mutual self-attention control after several denoising steps (e.g., step 5), and in the decoder part (e.g., layer \\(10 \\sim 15\\)) can preserve the shape and structure information from target prompt \\(P\\) and query contents from the source image with prompt \\(P_{s}\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.453, + 0.471, + 0.483 + ], + "angle": 0, + "content": "a significant limitation in synthesizing scenes with background dynamics." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.497, + 0.231, + 0.513 + ], + "angle": 0, + "content": "5.5. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.524, + 0.473, + 0.903 + ], + "angle": 0, + "content": "The results of both synthetic and real image editing can demonstrate the effectiveness of the proposed mutual self-attention control. We further analyze the control strategy in terms of different starting steps at the denoising process and the layers in the denoising U-Net. From Fig. 9(a), we see that performing mutual self-attention in the premature step can only synthesize an image identical to the source image, conveying all source image contents and ignoring the layout from the target prompt. As the step increases, the synthesized desired image can maintain the layout from the target prompt and the contents from the source image. While the image would gradually lose the source image contents and eventually becomes the image synthesized images without mutual self-attention control. We also observe a similar phenomenon when performing control in different U-Net layers shown in Fig. 9(b). Performing control among all layers can only generate an image identical to the source image. Performing control in low-resolution layers (i.e., layer \\(4 \\sim 10\\)) cannot preserve the source image contents and target layouts. While in high-resolution layers (i.e., layer \\(0 \\sim 3\\), \\(10 \\sim 15\\)), the target layout can be maintained, and the source image contents can only be transformed when controlled in the decoder part. As a result, the proposed method performs control in the decoder part of U-Net after several denoising steps." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.451, + 0.753, + 0.467 + ], + "angle": 0, + "content": "6. Limitations and Discussion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.477, + 0.893, + 0.583 + ], + "angle": 0, + "content": "Our method inherits most of the limitations of the Stable Diffusion model in generating desired images with text prompts. Please refer to the supplementary materials for detailed analysis and discussion. In addition, when editing real images, the DDIM inversion may fail to reconstruct the source images. In this case, MasaCtrl would fail to edit these images." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.596, + 0.62, + 0.611 + ], + "angle": 0, + "content": "7. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.621, + 0.895, + 0.865 + ], + "angle": 0, + "content": "We propose MasaCtrl, a tuning-free mutual self-attention control method applied to T2I diffusion models for non-rigid consistent image synthesis and editing. We convert the self-attention mechanism in diffusion models into a cross one, dubbed mutual self-attention, enabling effective structure and appearance query from the source image when applied to specific denoising steps and U-Net layers. We further consider the confusion problem of the foreground objects and background during the querying process and alleviate it with a mask-guided strategy. Meanwhile, our method can be easily integrated into recently proposed controllable strategies over diffusion models and perform consistent image synthesis and editing without fine-tuning the model and textural embedding. We believe such a method provides ordinary users with a convenient and effective way for content creation under text description." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.87, + 0.893, + 0.9 + ], + "angle": 0, + "content": "Acknowledgement. This research was partly supported by JSPS KAKENHI Grant Numbers 22H00529, 20H05951." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.926, + 0.521, + 0.938 + ], + "angle": 0, + "content": "22568" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.115, + 0.468, + 0.142 + ], + "angle": 0, + "content": "[1] Omri Avrahami, Ohad Fried, and Dani Lischinski. Blended latent diffusion. arXiv preprint arXiv:2206.02779, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.144, + 0.468, + 0.185 + ], + "angle": 0, + "content": "[2] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. arXiv preprint arXiv:1809.11096, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.187, + 0.468, + 0.241 + ], + "angle": 0, + "content": "[3] Hila Chefer, Yuval Alaluf, Yael Vinker, Lior Wolf, and Daniel Cohen-Or. Attend-and-excite: Attention-based semantic guidance for text-to-image diffusion models. arXiv preprint arXiv:2301.13826, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.243, + 0.468, + 0.311 + ], + "angle": 0, + "content": "[4] Katherine Crowson, Stella Biderman, Daniel Kornis, Dashiell Stander, Eric Hallahan, Louis Castricato, and Edward Raff. Vqgan-clip: Open domain image generation and editing with natural language guidance. In ECCV, pages 88–105. Springer, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.312, + 0.468, + 0.352 + ], + "angle": 0, + "content": "[5] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. NeurIPS, 34:8780-8794, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.354, + 0.468, + 0.408 + ], + "angle": 0, + "content": "[6] Ming Ding, Zhuoyi Yang, Wenyi Hong, Wendi Zheng, Chang Zhou, Da Yin, Junyang Lin, Xu Zou, Zhou Shao, Hongxia Yang, et al. Cogview: Mastering text-to-image generation via transformers. NeurIPS, 34:19822-19835, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.41, + 0.468, + 0.45 + ], + "angle": 0, + "content": "[7] Patrick Esser, Robin Rombach, and Bjorn Ommer. Taming transformers for high-resolution image synthesis. In CVPR, pages 12873-12883, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.452, + 0.468, + 0.508 + ], + "angle": 0, + "content": "[8] Shuyang Gu, Dong Chen, Jianmin Bao, Fang Wen, Bo Zhang, Dongdong Chen, Lu Yuan, and Baining Guo. Vector quantized diffusion model for text-to-image synthesis. In CVPR, pages 10696-10706, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.509, + 0.468, + 0.549 + ], + "angle": 0, + "content": "[9] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.551, + 0.468, + 0.605 + ], + "angle": 0, + "content": "[10] Amir Hertz, Ron Mokady, Jay Tenenbaum, Kfir Aberman, Yael Pritch, and Daniel Cohen-Or. Prompt-to-prompt image editing with cross attention control. arXiv preprint arXiv:2208.01626, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.607, + 0.468, + 0.634 + ], + "angle": 0, + "content": "[11] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. NeurIPS, 33:6840-6851, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.635, + 0.468, + 0.689 + ], + "angle": 0, + "content": "[12] Bahjat Kawar, Shiran Zada, Oran Lang, Omer Tov, Huiwen Chang, Tali Dekel, Inbar Mosseri, and Michal Irani. Imagc: Text-based real image editing with diffusion models. arXiv preprint arXiv:2210.09276, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.691, + 0.468, + 0.732 + ], + "angle": 0, + "content": "[13] Gwanghyun Kim, Taesung Kwon, and Jong Chul Ye. Diffusionclip: Text-guided diffusion models for robust image manipulation. In CVPR, pages 2426-2435, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.733, + 0.468, + 0.773 + ], + "angle": 0, + "content": "[14] Bowen Li, Xiaojuan Qi, Thomas Lukasiewicz, and Philip Torr. Controllable text-to-image generation. NeurIPS, 32, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.776, + 0.468, + 0.816 + ], + "angle": 0, + "content": "[15] Bowen Li, Xiaojuan Qi, Thomas Lukasiewicz, and Philip HS Torr. Manigan: Text-guided image manipulation. In CVPR, pages 7880-7889, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.468, + 0.871 + ], + "angle": 0, + "content": "[16] Chenlin Meng, Yang Song, Jiaming Song, Jiajun Wu, JunYan Zhu, and Stefano Ermon. Sdedit: Image synthesis and editing with stochastic differential equations. arXiv preprint arXiv:2108.01073, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.468, + 0.902 + ], + "angle": 0, + "content": "[17] Chong Mou, Xintao Wang, Liangbin Xie, Jian Zhang, Zhonggang Qi, Ying Shan, and Xiaohu Qie. T2i-adapter: Learning" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.115, + 0.468, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "adapters to dig out more controllable ability for text-to-image diffusion models. arXiv preprint arXiv:2302.08453, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.121, + 0.892, + 0.162 + ], + "angle": 0, + "content": "[18] Seonghyeon Nam, Yunji Kim, and Seon Joo Kim. Text-adaptive generative adversarial networks: manipulating images with natural language. NeurIPS, 31, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.163, + 0.892, + 0.231 + ], + "angle": 0, + "content": "[19] Alex Nichol, Prafulla Dhariwal, Aditya Ramesh, Pranav Shyam, Pamela Mishkin, Bob McGrew, Ilya Sutskever, and Mark Chen. Glide: Towards photorealistic image generation and editing with text-guided diffusion models. arXiv preprint arXiv:2112.10741, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.232, + 0.892, + 0.272 + ], + "angle": 0, + "content": "[20] Alexander Quinn Nichol and Prafulla Dhariwal. Improved denoising diffusion probabilistic models. In ICML, pages 8162-8171. PMLR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.274, + 0.892, + 0.315 + ], + "angle": 0, + "content": "[21] Gaurav Parmar, Krishna Kumar Singh, Richard Zhang, Yijun Li, Jingwan Lu, and Jun-Yan Zhu. Zero-shot image-to-image translation. arXiv preprint arXiv:2302.03027, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.316, + 0.892, + 0.357 + ], + "angle": 0, + "content": "[22] Or Patashnik, Zongze Wu, Eli Shechtman, Daniel Cohen-Or, and Dani Lischinski. Styleclip: Text-driven manipulation of stylegan imagery. In ICCV, pages 2085–2094, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.359, + 0.892, + 0.427 + ], + "angle": 0, + "content": "[23] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In ICML, pages 8748-8763. PMLR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.428, + 0.892, + 0.481 + ], + "angle": 0, + "content": "[24] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.484, + 0.892, + 0.537 + ], + "angle": 0, + "content": "[25] Aditya Ramesh, Mikhail Pavlov, Gabriel Goh, Scott Gray, Chelsea Voss, Alec Radford, Mark Chen, and Ilya Sutskever. Zero-shot text-to-image generation. In ICML, pages 8821-8831. PMLR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.539, + 0.892, + 0.593 + ], + "angle": 0, + "content": "[26] Scott Reed, Zeynep Akata, Xinchen Yan, Lajanugen Logeswaran, Bernt Schiele, and Honglak Lee. Generative adversarial text to image synthesis. In ICML, pages 1060-1069. PMLR, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.595, + 0.892, + 0.649 + ], + "angle": 0, + "content": "[27] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In CVPR, pages 10684-10695, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.651, + 0.892, + 0.692 + ], + "angle": 0, + "content": "[28] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In MICCAI, pages 234-241. Springer, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.692, + 0.892, + 0.748 + ], + "angle": 0, + "content": "[29] Nataniel Ruiz, Yuanzhen Li, Varun Jampani, Yael Pritch, Michael Rubinstein, and Kfir Aberman. Dreambooth: Fine tuning text-to-image diffusion models for subject-driven generation. arXiv preprint arXiv:2208.12242, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.749, + 0.892, + 0.83 + ], + "angle": 0, + "content": "[30] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.832, + 0.892, + 0.871 + ], + "angle": 0, + "content": "[31] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. arXiv preprint arXiv:2010.02502, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.873, + 0.892, + 0.902 + ], + "angle": 0, + "content": "[32] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. NeurIPS, 32, 2019." + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.926, + 0.521, + 0.938 + ], + "angle": 0, + "content": "22569" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[33] Raphael Tang, Akshit Pandey, Zhiying Jiang, Gefei Yang, Karun Kumar, Jimmy Lin, and Ferhan Ture. What the daam: Interpreting stable diffusion using cross attention. arXiv preprint arXiv:2210.04885, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.149, + 0.47, + 0.204 + ], + "angle": 0, + "content": "[34] Ming Tao, Hao Tang, Fei Wu, Xiao-Yuan Jing, Bing-Kun Bao, and Changsheng Xu. Df-gan: A simple and effective baseline for text-to-image synthesis. In CVPR, pages 16515-16525, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.207, + 0.471, + 0.26 + ], + "angle": 0, + "content": "[35] Narek Tumanyan, Michal Geyer, Shai Bagon, and Tali Dekel. Plug-and-play diffusion features for text-driven image-to-image translation. arXiv preprint arXiv:2211.12572, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.263, + 0.471, + 0.303 + ], + "angle": 0, + "content": "[36] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. NeurIPS, 30, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.305, + 0.471, + 0.374 + ], + "angle": 0, + "content": "[37] Jay Zhangjie Wu, Yixiao Ge, Xintao Wang, Weixian Lei, Yuchao Gu, Wynne Hsu, Ying Shan, Xiaohu Qie, and Mike Zheng Shou. Tune-a-video: One-shot tuning of image diffusion models for text-to-video generation. arXiv preprint arXiv:2212.11565, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.376, + 0.47, + 0.417 + ], + "angle": 0, + "content": "[38] Weihao Xia, Yujiu Yang, Jing-Hao Xue, and Baoyuan Wu. Tedigan: Text-guided diverse face image generation and manipulation. In CVPR, pages 2256-2265, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.419, + 0.47, + 0.473 + ], + "angle": 0, + "content": "[39] Tao Xu, Pengchuan Zhang, Qiuyuan Huang, Han Zhang, Zhe Gan, Xiaolei Huang, and Xiaodong He. Attngan: Fine-grained text to image generation with attentional generative adversarial networks. In CVPR, pages 1316-1324, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.476, + 0.47, + 0.529 + ], + "angle": 0, + "content": "[40] Hui Ye, Xiulong Yang, Martin Takac, Rajshekhar Sunderraman, and Shihao Ji. Improving text-to-image synthesis using contrastive learning. arXiv preprint arXiv:2107.02423, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.532, + 0.47, + 0.601 + ], + "angle": 0, + "content": "[41] Jiahui Yu, Yuanzhong Xu, Jing Yu Koh, Thang Luong, Gunjan Baid, Zirui Wang, Vijay Vasudevan, Alexander Ku, Yinfei Yang, Burcu Karagol Ayan, et al. Scaling autoregressive models for content-rich text-to-image generation. arXiv preprint arXiv:2206.10789, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.602, + 0.47, + 0.644 + ], + "angle": 0, + "content": "[42] Han Zhang, Jing Yu Koh, Jason Baldridge, Honglak Lee, and Yinfei Yang. Cross-modal contrastive learning for text-to-image generation. In CVPR, pages 833-842, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.645, + 0.47, + 0.713 + ], + "angle": 0, + "content": "[43] Han Zhang, Tao Xu, Hongsheng Li, Shaoting Zhang, Xiaogang Wang, Xiaolei Huang, and Dimitris N Metaxas. Stackgan: Text to photo-realistic image synthesis with stacked generative adversarial networks. In ICCV, pages 5907-5915, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.715, + 0.47, + 0.77 + ], + "angle": 0, + "content": "[44] Han Zhang, Tao Xu, Hongsheng Li, Shaoting Zhang, Xiaogang Wang, Xiaolei Huang, and Dimitris N Metaxas. Stackgan++: Realistic image synthesis with stacked generative adversarial networks. IEEE TPAMI, 41(8):1947-1962, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.772, + 0.47, + 0.813 + ], + "angle": 0, + "content": "[45] Lvmin Zhang and Maneesh Agrawala. Adding conditional control to text-to-image diffusion models. arXiv preprint arXiv:2302.05543, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.814, + 0.47, + 0.857 + ], + "angle": 0, + "content": "[46] Minfeng Zhu, Pingbo Pan, Wei Chen, and Yi Yang. Dm-gan: Dynamic memory generative adversarial networks for text-to-image synthesis. In CVPR, pages 5802-5810, 2019." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.857 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.927, + 0.52, + 0.938 + ], + "angle": 0, + "content": "22570" + } + ] +] \ No newline at end of file diff --git a/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/6e476140-cab6-422d-9817-a489e1ead454_origin.pdf b/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/6e476140-cab6-422d-9817-a489e1ead454_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..d5f1212909010d8fbd963e6cbe7a6c9f11218f34 --- /dev/null +++ b/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/6e476140-cab6-422d-9817-a489e1ead454_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:ccf8faede9410e03faa16726dd59121fd722f1bab66bfb097bd142885ce31bca +size 7999909 diff --git a/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/full.md b/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/full.md new file mode 100644 index 0000000000000000000000000000000000000000..22e8ab19906a94a9709894d70e5dcb6bc75a340d --- /dev/null +++ b/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/full.md @@ -0,0 +1,316 @@ +# MasaCtrl: Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing + +Mingdeng Cao $^{1,2*}$ Xintao Wang $^{2}$ Zhongang Qi $^{2}$ Ying Shan $^{2}$ Xiaohu Qie $^{2}$ Yinqiang Zheng $^{1}$ $^{1}$ The University of Tokyo ${}^{2}$ ARC Lab, Tencent PCG +https://github.com/TencentARC/MasaCtrl + +![](images/99d6a69dc4cce4ee20c38447e1f616a3bde67f89ed8cae7bc7e8bccf40826b33.jpg) +Input real image + +![](images/36a1938290766f5b3cc7ea1bbf3369d82ba8a349d1c9022b195e9fae4e93f8d7.jpg) +"A sitting boy" $\rightarrow$ "... standing ..." + +![](images/d6d8ade6f4570e9c392ff6822ca08cb9188645dd98dcf844b17bed52e4908a38.jpg) +Input real image "... , giving a thumbs up" + +![](images/a2fb0f168cdc05bfd60ace390b4f882da4197c7f4ff0b4aae1c809b93cb40cab.jpg) +"Elon Musk" $\rightarrow$ "... side view ..." + +![](images/df3b1a6b61a933b60d12f663e1aaf6d7784cb31df63436cc4915ab98b846ac7e.jpg) +"An apple" $\rightarrow$ "Two apples" + +![](images/86d0cf2101bc73836e0dcc7cfb727fb0b04ff029e212fe1d32a22103e3901dc0.jpg) +"A standing bird" $\rightarrow$ "..., spreading wings" +Figure 1: Our method MasaCtrl can perform text-based non-rigid image synthesis and real image editing without fine-tuning. Meanwhile, our method can be easily integrated into controllable diffusion models, like T2I-Adapter [17] or ControlNet [45], to perform more consistent and faithful synthesis and editing (last column). + +# Abstract + +Despite the success in large-scale text-to-image generation and text-conditioned image editing, existing methods still struggle to produce consistent generation and editing results. For example, generation approaches usually fail to synthesize multiple images of the same objects/characters but with different views or poses. Meanwhile, existing editing methods either fail to achieve effective complex non-rigid editing while maintaining the overall textures and identity, or require time-consuming fine-tuning to capture the image-specific appearance. In this paper, we develop MasaCtrl, a tuning-free method to achieve consistent image generation and complex non-rigid image editing simultaneously. Specifically, MasaCtrl converts existing self-attention in diffusion models into mutual self-attention, so that it can query correlated local contents and textures from source images for consistency. To further alleviate the query + +confusion between foreground and background, we propose a mask-guided mutual self-attention strategy, where the mask can be easily extracted from the cross-attention maps. Extensive experiments show that the proposed MasaCtrl can produce impressive results in both consistent image generation and complex non-rigid real image editing. + +# 1. Introduction + +Recent advances in text-to-image (T2I) generation [25, 19, 41, 24, 27] have achieved great success. Those large-scale T2I models, such as Stable Diffusion [27], can generate diverse and high-quality images conforming to given text prompts. When leveraging the T2I models, we can also perform promising text-conditioned image editing [19, 10, 35, 21]. However, there is still a large gap between our needs and existing methods in terms of consistent generation and editing. + +For the text-to-image generation, we usually want to generate several images of the same objects/characters but with different views or complex non-rigid variances (e.g., the changes of posture). Such capabilities are urgently needed for creating comic books and generating short videos using existing powerful T2I image models. However, this requirement is highly challenging. Even if we fix the input random noise and use very similar prompts (e.g., 'a sitting cat' vs. 'a laying cat' shown in Fig. 2), the generated images vary in both structures and identity. + +For text-conditioned image editing, existing methods [10, 35, 21] achieve impressive editing effects in image translation, stylization, and appearance replacement while keeping the input structure and scene layout unchanged. However, those methods usually fail to change poses or views while maintaining the overall textures and identity, leading to inconsistent editing results. The latter editing way is a more complicated non-rigid editing for practical use. Imagic [12] is then proposed to address this challenge. It allows complex non-rigid edits while preserving its original characteristics. It can make a standing dog sit down, cause a bird to spread its wings, etc. Nevertheless, it requires fine-tuning the entire T2I diffusion model and optimizing the textual embedding to capture the image-specific appearance for each edit, which is time-consuming and impractical for real-world applications. + +In this paper, we aim to develop a tuning-free method to address the above challenges, enabling a more consistent generation of multiple images and complex non-rigid editing without fine-tuning. The core challenge is how to keep consistent. Unlike previous works [10, 21, 3] that usually operate on cross-attention in T2I models, we propose to convert existing self-attention to mutual self-attention, so that it can query correlated local structures and textures from a source image for consistency. Specifically, we first generate an image from a random (or inverted a real image) noise, resulting in the denoising process (DP1) for the source image synthesis. In the new denoising process (DP2) of generating a new image or editing an existing one, we can use the Query features in DP2 self-attention to query the corresponding Key and Value features in DP1 self-attention. In other words, we transform the existing self-attention into 'cross-attention', where the crossing operation happens in the self-attention of two related denoising processes, rather than between the U-Net features and text embeddings. We call this 'crossing self-attention as mutual self-attention. However, directly applying this strategy can only generate images almost identical to the source image and cannot comply with the target text prompt (as analyzed in Fig. 9). Thus we further control the denoising timestep and the layer position in U-Net for performing mutual self-attention to achieve consistent synthesis and editing. More analyses are in Sec. 4.1 and Sec. 5.5. In this + +![](images/fc272f30003b45f0263635795511e6d1de79443672bf052a7e181bf7738f7073.jpg) +"...sitting..." + +![](images/13b42cee5fcc9c21834f61e69a72c2e5def9b65c41afd253f7206ef2422a7ac7.jpg) +...laying... + +![](images/4151ff38d4a99988f706d898202954d7e4e915f7a7305ae4b1f1a57537a31a0b.jpg) +...laying..." (Ours) + +![](images/0f6bd7f93692c214017a6e8fa521850b6cd5381e84aed7e17a7694039bf03c1b.jpg) +Source + +![](images/0c9714560e8b87a6d2d166223941d717cfaf04ef2d73a8244ecece4f373ef1fc.jpg) +w/o mask guidance + +![](images/dda00ec7413d8f0ce4e2ad05618ad2f298cce5311fd424672db1d89929449c19.jpg) +with mask guidance +Figure 2: First row: images synthesized from fixed random seed (middle, changed identity) and our method (right, maintained identity). Second row: image synthesized without mask guidance (middle) and with mask guidance (right). + +way, we can use contents in the source image as the generation material to better maintain the texture and identity. Meanwhile, its structure, pose, and non-rigid variances can be controlled by target text prompt, and guided by recent controllable T2I-Adapters [17] or ControlNet [45]. Fig. 1 shows some synthesis and editing examples. + +The proposed mutual self-attention control can work well for images with disentangled foreground and background, but may fail in the synthesis and editing process where the foreground and background have similar patterns and colors. In these cases, mutual self-attention tends to confuse the foreground and background, leading to a messy result (2nd row in Fig. 2). To address this problem, we further propose a mask-guided mutual self-attention. Specifically, we first utilize the cross attention in T2I diffusion models to extract a mask associated with the main object in the image. This mask can successfully separate foreground and background, and restrict the target foreground/background features to query only foreground/background features of the source image, respectively. Such an operation can effectively alleviate the query confusion between the foreground and background. + +Our contributions can be summarized as follows. 1) We propose a tuning-free method, namely, MasaCtrl, to simultaneously achieve consistent image synthesis and complex non-rigid image editing. 2) An effective mutual self-attention mechanism with delicate designs is proposed to change pose, view, structures, and non-rigid variances while maintaining the characteristics, texture, and identity. 3) To alleviate the query confusion between foreground and background, we further propose a masked-guided mutual self-attention, where the mask can be easily computed from the + +cross-attentions. 4) Experimental results have shown the effectiveness of our proposed MasaCtrl in both consistent image generation and complex non-rigid real image editing. + +# 2. Related Work + +# 2.1. Text-to-Image Generation + +Early image generation methods conditioned on text description mainly based on GANs [26, 43, 44, 39, 14, 2, 46, 40, 42, 34], due to their powerful capability of high-fidelity image synthesis. These models try to align the text descriptions and synthesized image contents via multimodal vision-language learning and have achieved cheerful synthesis results on domain-specific datasets. Text-to-image generation with auto-regressive and diffusion models has obtained impressive diversity results. DALL-E [25], CogView [6] and Parti [41], large-scale text-to-image models trained with a large amount of data, enable generating images from open-domain text descriptions. However, the auto-regressive generation nature leads to the slow generation process defect. Most recently, diffusion models [32, 11, 20, 5] have shown superior generative power and achieved state-of-the-art synthesis results in terms of image quality and diversity than previous GAN-based and auto-regressive image generation models. By conditioning the text prompt into the diffusion model, various text-to-image diffusion models GLIDE [19], VQ-Diffusion [8], LDM [27], DALL-E 2 [24], and Imagen [30] have been developed. They can synthesize high-quality images that highly comply with the given text description. + +# 2.2. Text-guided Image Editing. + +Text-guided image editing is a challenging task that aims to manipulate images according to natural language descriptions. Previous methods based on generative adversarial networks (GANs) [18, 15, 38, 22] have achieved some success on domain-specific datasets (e.g., face datasets), but they have limited applicability and generality. A recent approach based on auto-regressive models, VQGAN-CLIP [4], combines VQGAN [7] and CLIP [23] to produce high-quality images and precise edits with diverse and controllable results. However, this approach suffers from slow generation speed and high computational cost. + +Different from previous methods based on GANs or auto-regressive models, diffusion models offer a fast and efficient way to synthesize and edit images conditioned on text prompts. However, existing diffusion-based methods have some limitations regarding local and global editing. For example, the works [19, 1] require extra masks to edit local regions of the image; [13] can edit global aspects of the image by changing the text prompt directly, but cannot modify local details; [10, 35] use cross-attention or spatial features to edit both global and local aspects of the image + +by changing the text prompt directly. Still, they tend to preserve the original layout of the source image and fail to handle non-rigid transformations (e.g., changing object pose). In contrast, we propose a novel approach that leverages the self-attention mechanism to achieve consistent and complex non-rigid image synthesis and editing. Our approach can modify various object attributes (e.g., pose, shape) by changing the text prompt accordingly. The most related work to ours is Imagic [12], which also enables various prompt-based non-rigid image editing. However, unlike our approach can edit images on the fly, Imagic requires careful optimization of the textual embedding and fine-tuning of the model, which is time-consuming and unfriendly for ordinary users. + +# 3. Preliminaries + +# 3.1. Latent Diffusion Models + +Diffusion models [11, 31, 20] are generative models that can synthesize desired data samples from Gaussian noise via iterative denoising. Our method is based on the recent state-of-the-art text-conditioned model Stable Diffusion (SD) [27], which performs the diffusion-denoising process in the latent rather than image space. Specifically, a pretrained image autoencoder first encodes the image $x$ into latent representations $z$ . Then the denoising network $\epsilon_{\theta}$ (a time-conditional U-Net [28]) is trained in this latent space. After being trained, we can sample a random noise $z_{T} \sim \mathcal{N}(0,1)$ and perform the latent denoising process. The denoised latent representation $z_{0}$ can be decoded into an image using the pretrained autoencoder. + +# 3.2. Attention Mechanism in Stable Diffusion + +The denoising U-Net $\epsilon_{\theta}$ in the SD model, consists of a series of basic blocks, and each basic block contains a residual block [9], a self-attention module, and a cross-attention [36] module. At denoising step $t$ , the features from the previous $(l - 1)$ -th basic block first pass through the residual block to generate intermediate features $f_{t}^{l}$ ; then they are reorganized by the self-attention layer, and receive textual information from the text prompt $P$ by the following cross-attention layer. The attention mechanism can be formulated as follows: + +$$ +\operatorname {A t t e n t i o n} (Q, K, V) = \operatorname {S o f t m a x} \left(\frac {Q K ^ {T}}{\sqrt {d}}\right) V, \tag {1} +$$ + +where $Q$ is the query features projected from the spatial features, and $K, V$ are the key and value features projected from the spatial features (in self-attention layers) or the textual embedding (in cross-attention layers) with corresponding projection matrices. $A = \operatorname{Softmax}\left(\frac{QK^T}{\sqrt{d}}\right)$ is the attention map used to aggregate the value $V$ . + +![](images/544b0184a63e05419f081618b6a5d83cbbdb4c6fcb88d7b76308dc53997e26b1.jpg) +Figure 3: Pipeline of the proposed MasaCtrl. Our method tries to perform complex non-rigid image editing and synthesize content-consistent images. The source image is either real or synthesized with source text prompt $P_{s}$ . During the denoising process for image synthesis, we convert the self-attention into mutual self-attention to query image contents from source image $I_{s}$ , so that we can synthesize content-consist images under the modified target prompt $P$ . + +These attention layers in the SD model contain much information for the overall structure/layout and content formation of the synthesized image [10, 35]. The internal cross-attention maps are high-dimensional tensors that bind the spatial pixels and textual embedding [10], and they are explored for image editing [10] and faithful image synthesis [3]. In addition, the features in the self-attention layer are employed as plug-and-play features to be injected into specified U-Net layers to perform image translation. However, these controls cannot perform non-rigid editing (e.g., pose change) since they maintain the semantic layout and structures. Inspired by the phenomenon that performing self-attention across batches can generate similar image contents, which is also observed in Tune-A-Video [37], we adapt the self-attention mechanism in the T2I model to query contents from source images with delicate designs. Thus we can perform consistent synthesis and non-rigid editing that change the layout and structure of the source image while preserving image contents. + +# 4. Tuning-Free Mutual Self-Attention Control + +Given a source image $I_{s}$ and the corresponding text prompt $P_{s}$ , our goal is to synthesize the desired image $I$ that complies with the target edited text prompt $P$ (directly modified from $P_{s}$ ). Note that the edited target image $I$ is spatially edited from $I_{s}$ and should preserve the object contents (e.g., textures and identity) in $I_{s}$ . For instance, consider a photo (corresponding to $P_{s}$ ) where a dog is sitting, + +and we want the dog to be in the running pose with the edited text prompt $P$ that adds the 'running' into the source prompt $P_{s}$ (see Fig. 3). + +Our core idea is to combine the semantic layout synthesized with the target prompt $P$ and the contents in the source image $I_{s}$ to synthesize the desired image $I$ . To achieve so, we propose MasaCtrl, which adapts the self-attention mechanism in the SD model into a crossing one to query semantically similar contents from the source image. Consequently, the target image $I$ can be synthesized by querying the contents from $I_{s}$ with the modified self-attention mechanism during the denoising process. We can achieve so for the following reasons: 1) the image layout is formed in the early denoising steps (shown in Fig. 4(a)); 2) in addition, as shown in Fig. 4(b), the encoded query features in the self-attention layer are semantically corresponded (e.g., the horses are in the same color), thus one can query content information from another. + +The overall architecture of the proposed pipeline to perform synthesis and editing is shown in Fig. 3, and the algorithm is summarized in Alg. 1. The input source image $I_{s}$ is either a real image or a generated one from the SD model with text prompt $P_{s}$ . During each denoising step $t$ of synthesizing target image $I$ , we assemble the inputs of + +Algorithm 1 MasaCtrl: Tuning-Free Mutual Self-Attention Control + +Input: A source prompt $P_{s}$ , a modified prompt $P$ , the source and target initial latent noise maps $z_{T}^{s}$ and $z_{T}$ . + +Output: Latent map $z_0^s$ , edited latent map $z_0$ corresponding to $P_s$ and $P$ . + +1: for $t = T, T - 1, \ldots, 1$ do +2: $\epsilon_s, \{Q_s, K_s, V_s\} \gets \epsilon_\theta(z_t^s, P_s, t)$ ; +3: $z_{t - 1}^{s}\gets \mathrm{Sample}(z_{t}^{s},\epsilon_{s})$ +4: $\{Q,K,V\} \gets \epsilon_{\theta}(z_t,P,t)$ +5: $\{Q^{*},K^{*},V^{*}\} \leftarrow$ EDIT( $\{Q,K,V\},\{Q_{s},K_{s},V_{s}\}$ ); +6: $\epsilon = \epsilon_{\theta}(z_t,P,t;\{Q^*,K^*,V^*\})$ +7: $z_{t - 1}\gets \mathrm{Sample}(z_t,\epsilon);$ +8: end for + +Return $z_0^s, z_0$ + +the self-attention by 1) keeping the current Query features $Q$ unchanged, and 2) obtaining the Key and Value features $K_{s}$ , $V_{s}$ from the self-attention layer in the process of synthesizing source image $I_{s}$ . We dub this strategy mutual self-attention, and more details are in Sec. 4.1. + +Meanwhile, we also observe the edited image often suffers from the problem of confusion between the foreground objects and background. Thus, we propose a mask-aware mutual self-attention strategy guided by the masks obtained from the cross-attention mechanism. The object mask is automatically generated from the cross-attention maps of the text token associated with the foreground object. Please refer to Sec. 4.2 for more details. + +In addition, since the edited prompt $P$ may not yield desired spatial layouts due to the inner limitations of the SD model, MasaCtrl can be easily integrated into existing controllable image synthesis method (e.g., T2I-Adapter [17] and ControlNet [45]) for more faithful non-rigid image editing. Please refer to Sec. 4.3 for more details. + +# 4.1. Mutual Self-Attention + +As shown in the left part of Fig. 5(a), at denoising step $t$ and layer $l$ , the query features are defined as the projected query features $Q^l$ in the self-attention module, and the content features are the key features $K_s^l$ and value features $V_s^l$ from the corresponding self-attention layer in the process of reconstructing the source image $I_s$ . After that, we perform attention according to Eq. 1 to aggregate the contents from the source image. + +However, intuitively performing such attention on all layers among all denoising steps will result in a failed image $I$ that is nearly the same as the reconstructed image $I_{s}$ . We argue the reason is that performing self-attention control in the early steps can disrupt the layout formation of the target image. In the premature denoising steps, the target image layout has not yet been formed (shown in Fig. 4(a)). + +![](images/8104f59f1e064b84f081b37a5ff4c779c280e77a747a173fa51b79500b78ba98.jpg) +(a) Intermediate results in denoising process + +![](images/5fd292d44cab9e25505b8168b7eb06ccfdf0336af66d0339a21081731ef43180.jpg) +(b) Query feature visualization +Figure 4: (a) The intermediate results during the iterative denoising process, and (b) visualization of the projected Query features $Q$ in the self-attention layers of the U-Net at the 15th sampling step. + +We further observe the Query features in the shallow layers of U-Net (e.g., encoder part) cannot obtain clear layout and structure corresponding to the modified prompt (shown in Fig. 4(b)). Thus we cannot obtain the image with the desired spatial layout. + +Therefore, we propose to control the mutual self-attention only in the decoder part of the $U$ -Net after several denoising steps, due to the formed clear target image layout and semantically similar features (see Fig. 4). We can change the original layout into the target one with edited prompt $P$ and keep the main objects unchanged with proper starting denoising step $S$ and layer $L$ for synthesis and editing. Thus the EDIT function in Alg. 1 can be formulated as follows: + +$$ +\operatorname {E D I T} := \left\{ \begin{array}{l l} \left\{Q, K _ {s}, V _ {s} \right\}, & \text {i f} \quad T - t > S \quad \text {a n d} \quad l > L, \\ \left\{Q, K, V \right\}, & \text {o t h e r w i s e ,} \end{array} \right. \tag {2} +$$ + +where $S$ and $L$ are the timestep and layer index to start attention control, respectively. $T$ is the total denoising steps. + +In the early steps, the composition and shape of the object can be roughly generated, complying with the target prompt $P$ . Then the content information from the source image $I_{s}$ is queried by the mutual self-attention mechanism to fill the generated layout of target image $I$ . After iterative denoising, we can obtain the synthesized image with similar contents in the source image and structure of $I^{*}$ that complied with the input prompt. Note that our algorithm does not require fine-tuning or optimization, bringing many conveniences for ordinary users for content creation. + +![](images/8e1baa964161870e1099e38361e2c753df020ba7575ab50b8336fd28cd4faca4.jpg) +(a) Mutual self-attention control + +![](images/a9305591d9c94c8220f85a9113f75708751b2136a6be26cc40629e355473ded0.jpg) +(b) Mask extraction from cross-attention maps +Figure 5: (a) The mutual self-attention mechanism and control strategy in the decoder part of denoising U-Net to query contents from the source image; and (b) mask extraction strategy from cross-attention maps. + +# 4.2. Mask-Guided Mutual Self-Attention + +We also observed the above synthesis/editing would fail when the object and background are too similar to be confused. One feasible way to tackle this problem is to segment the image into the foreground and background parts and query contents only from the corresponding parts. Inspired by previous work [10, 33], the cross-attention maps correlating to the prompt tokens contain most information of the shape and structure. Therefore, we utilize the semantic cross-attention maps to create a mask to distinguish the foreground and background in both source and target images $I_{s}$ and $I$ . + +Specifically, at step $t$ , we first perform forward passes with source prompt $P_{s}$ and edited prompt $P$ , respectively, to generate intermediate cross-attention maps. Then we average the cross-attention maps across all heads and layers with the spatial resolution $16 \times 16$ . The resulting cross-attention maps are denoted as $A_{t}^{c} \in \mathbb{R}^{16 \times 16 \times N}$ , where $N$ is the number of the textual tokens. We then obtain the averaged cross-attention map for the token correlated to the foreground object. We denote $M_{s}$ and $M$ as masks extracted for the foreground objects in $I_{s}$ and $I$ , respectively. With these masks, we can restrict the object in $I$ to query + +contents information only from the object region in $I_{s}$ : + +$$ +f _ {o} ^ {l} = \text {A t t e n t i o n} \left(Q ^ {l}, K _ {s} ^ {l}, V _ {s} ^ {l}; M _ {s}\right), \tag {3} +$$ + +$$ +f _ {b} ^ {l} = \text {A t t e n t i o n} \left(Q ^ {l}, K _ {s} ^ {l}, V _ {s} ^ {l}; 1 - M _ {s}\right), \tag {4} +$$ + +$$ +\bar {f} ^ {l} = f _ {o} ^ {l} * M + f _ {b} ^ {l} * (1 - M), \tag {5} +$$ + +where $\bar{f}^l$ is the final attention output. The object and background regions in the target image query the contents from corresponding restricted areas rather than all source image features. Note that this strategy is optional and used when confusion occurs. + +# 4.3. Integration to Controllable Diffusion Models + +Our method can be integrated into existing controllable diffusion models (e.g., T2I-Adapter [17] and ControlNet [45]) for more faithful non-rigid image synthesis and editing. These methods enable the original Stable Diffusion model to be more controllable (e.g., pose, sketch, segmentation map) in image synthesis. Thus we can use them to synthesize images with desired poses and shapes. Since our method can query image contents (e.g., textures) from a reference image, we can easily integrate our approach into these models to generate more consistent images. + +Specifically, we follow the same process depicted in Alg. 1, and the desired target image synthesis process is changed from the original SD model to using these controllable models instead. In the following experiment section, we demonstrate the effectiveness of such a combination that can synthesize images consistently. + +# 5. Experiments + +Setup. We apply the proposed method to the state-of-the-art text-to-image Stable Diffusion [27] model with publicly available checkpoints v1.4. We also validate the proposed method on the pre-trained anime-style model Anything-V4. Meanwhile, we perform editing on both synthetic images and real images. For real image editing, we first invert the image into the initial noise map with DDIM deterministic inversion [31]. Note that we set the starting noise map the same for source prompt $P_{s}$ and the desired prompt $P$ unless otherwise specified. During sampling, we perform DDIM sampling [31] with 50 denoising steps, and the classifier-free guidance is set to 7.5. The step and layer to start attention control is set to $S = 4$ , $L = 10$ as default. Note that it may be changed for specific checkpoints. + +# 5.1. Comparisons with Previous Works + +We mainly compare the proposed tuning-free method to the current prompt-based editing methods with diffusion models, including tuning-free methods SDEdit [16], P2P [10], PnP [35], and Imagc [12]. We use their open-sourced codes to produce the editing results2. + +![](images/7e8cd60ed70b342e7d572ae83f21cbbc09ff5b5b74c6af4eac910904178ab54e.jpg) +Figure 6: Editing results of different methods on the synthetic images (a) and real images (b). Our method enables consistent synthesis by combining the layout of the target prompt and the contents of source generated image. From left to right: the source generated source image with source prompt, synthesis results with the proposed MasaCtrl method, synthesis results from target prompt with the same random noise of source image, synthesis/editing results with existing methods P2P [10], SDEdit [16], PnP [35], and Imagc [12]. + +![](images/61d3aaf56ab96999494c435e35833206ec53446ba1c0dbb8353d4736c9f401c1.jpg) +Figure 7: Editing results of synthetic images (left part) and real images (right part) with MasaCtrl integrated into T2I-Adapter [17]. + +Qualitative comparison. The consistent synthesis results are shown in Fig. 6(a). By directly modifying the text prompt, our method can synthesize content-consistent images. These synthesized images (1) contain contents (foreground objects and background) that are highly similar to those in the generated source images (first column of Fig. 6) and (2) highly comply with the target prompt $P$ (third col + +![](images/b7b62ebe10786e9a150e928bc268d39462bd8090767b1988986e6d4805fcd794.jpg) + +unn of Fig. 6). While existing methods fail to synthesize desired images, either conforming to the target text prompt or inconsistent with the source images. Our method also achieves promising results in editing real images shown in Fig. 6(b). The edited image is consistent with the target prompt and maintains source image content. These results demonstrate the effectiveness of the proposed method. + +![](images/44b04ab1a0e4304da209bc6bbc5a5e6656cf732ad8c556f0fe943d15c0c352f3.jpg) +Figure 8: Video synthesis results of proposed MasaCtrl with T2I-Adapter [17] (with key-pose guidance). + +Quantitative comparison. For quantitative evaluation, we used 20 different source images (10 are synthetic and 10 are real) and edited them with P2P, PnP, Imagic, and MasaCtrl. We evaluate the text-alignment between the target prompt and edited image, and the image-alignment between the source and edited images in the CLIP feature space. Tab. 1 shows that MasaCtrl can synthesize images that comply with the target prompt while maintaining content consistency more than other methods. We also conducted a user study and collected 700 answers from professional participants. As shown in the preference column of Tab. 1, $73.5\%$ of participants preferred our method. Meanwhile, our method is efficient since no fine-tuning and optimization are required. + +We further analyze the reasons attributed to the failure of existing methods (i.e., P2P, SDEdit, and PnP). These methods try to keep the original layout or object shape and pose unchanged by leveraging the layout information encoded in the cross-attention maps (P2P), features (PnP), and original input images (SDEdit). Meanwhile, the contents in the formed image mainly come from the encoded text embedding. As a result, the images synthesized by these methods have similar layouts to the source image but have different contents. In our proposed method MasaCtrl, the structure of the desired image is first determined by the former iteration in the denoising process, and the final image is formed by obtaining the image content from the source image. Thus we can perform various types of non-rigid image editing. + +# 5.2. Results with T2I-Adapter + +The initial layout controlled by modifying the text prompt usually fails due to the inherent drawbacks of the Stable Diffusion model. Therefore, we further integrate our method into existing controllable synthesis pipelines to obtain stable synthesis and editing results. The synthetic and real image editing results of MasaCtrl with T2I- + +
MethodText-alignmentImage-alignmentPreferenceRuntime
P2P [10]0.26910.87933.0%15s
PnP [35]0.25890.89022.5%60s
Imagic [12]0.26880.915921.0%14min
Ours0.27930.928673.5%16s
+ +Table 1: Quantitative and user study results. + +Adapter [17] are shown in Fig. 7. We see that T2I-Adapter can generate an image with desired target layout, yet with different contents in the source image. In contrast, our method can effectively combine the layout synthesized by T2I-Adapter with the target prompt and the contents in the source image. Therefore, more faithful and fine-grained synthesis and editing results can be obtained. Note that we may change the attention strategy of starting denoising step $S$ and U-Net layer $L$ to obtain faithful results ( $S = 2$ , $L = 8$ in our experiment), since the target layout is strongly controlled by extra guidance. Therefore, we can perform attention control in early steps and layers to query faithful contents in the source image, refer to the ablation study Sec. 5.5 for the analysis. + +# 5.3. Robustness to Other Models + +Our method can be applied to other versions of Stable Diffusion models (e.g., v1.5), domain-specific models (e.g., the amine-style model Anything-v4), and customized models (e.g., models fine-tuned with DreamBooth [29]) to achieve consistent image synthesis and editing. Please refer to the supplementary materials for the visual results. + +# 5.4. Extension to Video Synthesis + +Although our method is designed for consistent image synthesis and editing, we can easily extend our method for the video synthesis task using T2I-Adapter and ControlNet with a series of dense temporal-coherent guidance (e.g., pose, edge, depth). Specifically, we first generate a source image with the prompt $P_{s}$ and guidance as the canonical frame (shown in the first column of Fig. 8). The other frames are synthesized separately with MasaCtrl. Then all the synthesized frames can be concatenated into a video since they are content-consistent with the source frame. Fig. 8 shows the video synthesis results with coherent dense guidance. The proposed method successfully synthesizes consistent frames with highly similar content (more video results are available on the project page and supplementary materials). However, our method can only animate the foreground objects (such as the bear in Fig. 8) and hardly bring the background alive. Therefore, video-based approaches still need to be explored since the current MasaCtrl has + +![](images/039fd558c9fa8f06f3c107ba23d87462b8aab3e79b08806e755ec597eeb96827.jpg) + +![](images/3b95bc034362513c8e21e16b0e2fa7bb409bbca8b2ea333cb358f4527e43e5bc.jpg) + +![](images/de95c48bb13b21a25fb6973b50b5f136dcdfb54526a0d1578d42e161257d54b0.jpg) +(a) Results of mutual self-attention control starting from different denoising steps +(b) Results of mutual self-attention control in different U-Net layers +Figure 9: Results of mutual self-attention control in different denoising steps (a) and different U-Net layers (b). We see that only performing mutual self-attention control after several denoising steps (e.g., step 5), and in the decoder part (e.g., layer $10 \sim 15$ ) can preserve the shape and structure information from target prompt $P$ and query contents from the source image with prompt $P_{s}$ . + +a significant limitation in synthesizing scenes with background dynamics. + +# 5.5. Ablation Study + +The results of both synthetic and real image editing can demonstrate the effectiveness of the proposed mutual self-attention control. We further analyze the control strategy in terms of different starting steps at the denoising process and the layers in the denoising U-Net. From Fig. 9(a), we see that performing mutual self-attention in the premature step can only synthesize an image identical to the source image, conveying all source image contents and ignoring the layout from the target prompt. As the step increases, the synthesized desired image can maintain the layout from the target prompt and the contents from the source image. While the image would gradually lose the source image contents and eventually becomes the image synthesized images without mutual self-attention control. We also observe a similar phenomenon when performing control in different U-Net layers shown in Fig. 9(b). Performing control among all layers can only generate an image identical to the source image. Performing control in low-resolution layers (i.e., layer $4 \sim 10$ ) cannot preserve the source image contents and target layouts. While in high-resolution layers (i.e., layer $0 \sim 3$ , $10 \sim 15$ ), the target layout can be maintained, and the source image contents can only be transformed when controlled in the decoder part. As a result, the proposed method performs control in the decoder part of U-Net after several denoising steps. + +# 6. Limitations and Discussion + +Our method inherits most of the limitations of the Stable Diffusion model in generating desired images with text prompts. Please refer to the supplementary materials for detailed analysis and discussion. In addition, when editing real images, the DDIM inversion may fail to reconstruct the source images. In this case, MasaCtrl would fail to edit these images. + +# 7. Conclusion + +We propose MasaCtrl, a tuning-free mutual self-attention control method applied to T2I diffusion models for non-rigid consistent image synthesis and editing. We convert the self-attention mechanism in diffusion models into a cross one, dubbed mutual self-attention, enabling effective structure and appearance query from the source image when applied to specific denoising steps and U-Net layers. We further consider the confusion problem of the foreground objects and background during the querying process and alleviate it with a mask-guided strategy. Meanwhile, our method can be easily integrated into recently proposed controllable strategies over diffusion models and perform consistent image synthesis and editing without fine-tuning the model and textural embedding. We believe such a method provides ordinary users with a convenient and effective way for content creation under text description. + +Acknowledgement. This research was partly supported by JSPS KAKENHI Grant Numbers 22H00529, 20H05951. + +# References + +[1] Omri Avrahami, Ohad Fried, and Dani Lischinski. Blended latent diffusion. arXiv preprint arXiv:2206.02779, 2022. +[2] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. arXiv preprint arXiv:1809.11096, 2018. +[3] Hila Chefer, Yuval Alaluf, Yael Vinker, Lior Wolf, and Daniel Cohen-Or. Attend-and-excite: Attention-based semantic guidance for text-to-image diffusion models. arXiv preprint arXiv:2301.13826, 2023. +[4] Katherine Crowson, Stella Biderman, Daniel Kornis, Dashiell Stander, Eric Hallahan, Louis Castricato, and Edward Raff. Vqgan-clip: Open domain image generation and editing with natural language guidance. In ECCV, pages 88–105. Springer, 2022. +[5] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. NeurIPS, 34:8780-8794, 2021. +[6] Ming Ding, Zhuoyi Yang, Wenyi Hong, Wendi Zheng, Chang Zhou, Da Yin, Junyang Lin, Xu Zou, Zhou Shao, Hongxia Yang, et al. Cogview: Mastering text-to-image generation via transformers. NeurIPS, 34:19822-19835, 2021. +[7] Patrick Esser, Robin Rombach, and Bjorn Ommer. Taming transformers for high-resolution image synthesis. In CVPR, pages 12873-12883, 2021. +[8] Shuyang Gu, Dong Chen, Jianmin Bao, Fang Wen, Bo Zhang, Dongdong Chen, Lu Yuan, and Baining Guo. Vector quantized diffusion model for text-to-image synthesis. In CVPR, pages 10696-10706, 2022. +[9] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778, 2016. +[10] Amir Hertz, Ron Mokady, Jay Tenenbaum, Kfir Aberman, Yael Pritch, and Daniel Cohen-Or. Prompt-to-prompt image editing with cross attention control. arXiv preprint arXiv:2208.01626, 2022. +[11] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. NeurIPS, 33:6840-6851, 2020. +[12] Bahjat Kawar, Shiran Zada, Oran Lang, Omer Tov, Huiwen Chang, Tali Dekel, Inbar Mosseri, and Michal Irani. Imagc: Text-based real image editing with diffusion models. arXiv preprint arXiv:2210.09276, 2022. +[13] Gwanghyun Kim, Taesung Kwon, and Jong Chul Ye. Diffusionclip: Text-guided diffusion models for robust image manipulation. In CVPR, pages 2426-2435, 2022. +[14] Bowen Li, Xiaojuan Qi, Thomas Lukasiewicz, and Philip Torr. Controllable text-to-image generation. NeurIPS, 32, 2019. +[15] Bowen Li, Xiaojuan Qi, Thomas Lukasiewicz, and Philip HS Torr. Manigan: Text-guided image manipulation. In CVPR, pages 7880-7889, 2020. +[16] Chenlin Meng, Yang Song, Jiaming Song, Jiajun Wu, JunYan Zhu, and Stefano Ermon. Sdedit: Image synthesis and editing with stochastic differential equations. arXiv preprint arXiv:2108.01073, 2021. +[17] Chong Mou, Xintao Wang, Liangbin Xie, Jian Zhang, Zhonggang Qi, Ying Shan, and Xiaohu Qie. T2i-adapter: Learning + +adapters to dig out more controllable ability for text-to-image diffusion models. arXiv preprint arXiv:2302.08453, 2023. +[18] Seonghyeon Nam, Yunji Kim, and Seon Joo Kim. Text-adaptive generative adversarial networks: manipulating images with natural language. NeurIPS, 31, 2018. +[19] Alex Nichol, Prafulla Dhariwal, Aditya Ramesh, Pranav Shyam, Pamela Mishkin, Bob McGrew, Ilya Sutskever, and Mark Chen. Glide: Towards photorealistic image generation and editing with text-guided diffusion models. arXiv preprint arXiv:2112.10741, 2021. +[20] Alexander Quinn Nichol and Prafulla Dhariwal. Improved denoising diffusion probabilistic models. In ICML, pages 8162-8171. PMLR, 2021. +[21] Gaurav Parmar, Krishna Kumar Singh, Richard Zhang, Yijun Li, Jingwan Lu, and Jun-Yan Zhu. Zero-shot image-to-image translation. arXiv preprint arXiv:2302.03027, 2023. +[22] Or Patashnik, Zongze Wu, Eli Shechtman, Daniel Cohen-Or, and Dani Lischinski. Styleclip: Text-driven manipulation of stylegan imagery. In ICCV, pages 2085–2094, 2021. +[23] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In ICML, pages 8748-8763. PMLR, 2021. +[24] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022. +[25] Aditya Ramesh, Mikhail Pavlov, Gabriel Goh, Scott Gray, Chelsea Voss, Alec Radford, Mark Chen, and Ilya Sutskever. Zero-shot text-to-image generation. In ICML, pages 8821-8831. PMLR, 2021. +[26] Scott Reed, Zeynep Akata, Xinchen Yan, Lajanugen Logeswaran, Bernt Schiele, and Honglak Lee. Generative adversarial text to image synthesis. In ICML, pages 1060-1069. PMLR, 2016. +[27] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In CVPR, pages 10684-10695, 2022. +[28] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In MICCAI, pages 234-241. Springer, 2015. +[29] Nataniel Ruiz, Yuanzhen Li, Varun Jampani, Yael Pritch, Michael Rubinstein, and Kfir Aberman. Dreambooth: Fine tuning text-to-image diffusion models for subject-driven generation. arXiv preprint arXiv:2208.12242, 2022. +[30] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022. +[31] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. arXiv preprint arXiv:2010.02502, 2020. +[32] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. NeurIPS, 32, 2019. + +[33] Raphael Tang, Akshit Pandey, Zhiying Jiang, Gefei Yang, Karun Kumar, Jimmy Lin, and Ferhan Ture. What the daam: Interpreting stable diffusion using cross attention. arXiv preprint arXiv:2210.04885, 2022. +[34] Ming Tao, Hao Tang, Fei Wu, Xiao-Yuan Jing, Bing-Kun Bao, and Changsheng Xu. Df-gan: A simple and effective baseline for text-to-image synthesis. In CVPR, pages 16515-16525, 2022. +[35] Narek Tumanyan, Michal Geyer, Shai Bagon, and Tali Dekel. Plug-and-play diffusion features for text-driven image-to-image translation. arXiv preprint arXiv:2211.12572, 2022. +[36] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. NeurIPS, 30, 2017. +[37] Jay Zhangjie Wu, Yixiao Ge, Xintao Wang, Weixian Lei, Yuchao Gu, Wynne Hsu, Ying Shan, Xiaohu Qie, and Mike Zheng Shou. Tune-a-video: One-shot tuning of image diffusion models for text-to-video generation. arXiv preprint arXiv:2212.11565, 2022. +[38] Weihao Xia, Yujiu Yang, Jing-Hao Xue, and Baoyuan Wu. Tedigan: Text-guided diverse face image generation and manipulation. In CVPR, pages 2256-2265, 2021. +[39] Tao Xu, Pengchuan Zhang, Qiuyuan Huang, Han Zhang, Zhe Gan, Xiaolei Huang, and Xiaodong He. Attngan: Fine-grained text to image generation with attentional generative adversarial networks. In CVPR, pages 1316-1324, 2018. +[40] Hui Ye, Xiulong Yang, Martin Takac, Rajshekhar Sunderraman, and Shihao Ji. Improving text-to-image synthesis using contrastive learning. arXiv preprint arXiv:2107.02423, 2021. +[41] Jiahui Yu, Yuanzhong Xu, Jing Yu Koh, Thang Luong, Gunjan Baid, Zirui Wang, Vijay Vasudevan, Alexander Ku, Yinfei Yang, Burcu Karagol Ayan, et al. Scaling autoregressive models for content-rich text-to-image generation. arXiv preprint arXiv:2206.10789, 2022. +[42] Han Zhang, Jing Yu Koh, Jason Baldridge, Honglak Lee, and Yinfei Yang. Cross-modal contrastive learning for text-to-image generation. In CVPR, pages 833-842, 2021. +[43] Han Zhang, Tao Xu, Hongsheng Li, Shaoting Zhang, Xiaogang Wang, Xiaolei Huang, and Dimitris N Metaxas. Stackgan: Text to photo-realistic image synthesis with stacked generative adversarial networks. In ICCV, pages 5907-5915, 2017. +[44] Han Zhang, Tao Xu, Hongsheng Li, Shaoting Zhang, Xiaogang Wang, Xiaolei Huang, and Dimitris N Metaxas. Stackgan++: Realistic image synthesis with stacked generative adversarial networks. IEEE TPAMI, 41(8):1947-1962, 2018. +[45] Lvmin Zhang and Maneesh Agrawala. Adding conditional control to text-to-image diffusion models. arXiv preprint arXiv:2302.05543, 2023. +[46] Minfeng Zhu, Pingbo Pan, Wei Chen, and Yi Yang. Dm-gan: Dynamic memory generative adversarial networks for text-to-image synthesis. In CVPR, pages 5802-5810, 2019. \ No newline at end of file diff --git a/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/images.zip b/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..40ceed4095fc74c9599623da187fc221d32ca956 --- /dev/null +++ b/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:4abdb6ea5777c34e389f8933b3cb2127d563c28f751beeb77830514a56de7b7f +size 881404 diff --git a/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/layout.json b/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..387b753a9e9064bfd370974e52c74fe169ed12ac --- /dev/null +++ b/2023/MasaCtrl_ Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing/layout.json @@ -0,0 +1,9853 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 83, + 102, + 510, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 83, + 102, + 510, + 140 + ], + "spans": [ + { + "bbox": [ + 83, + 102, + 510, + 140 + ], + "type": "text", + "content": "MasaCtrl: Tuning-Free Mutual Self-Attention Control for Consistent Image Synthesis and Editing" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "spans": [ + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "text", + "content": "Mingdeng Cao" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "inline_equation", + "content": "^{1,2*}" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "text", + "content": " Xintao Wang" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "text", + "content": " Zhongang Qi" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "text", + "content": " Ying Shan" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "text", + "content": " Xiaohu Qie" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "text", + "content": " Yinqiang Zheng" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "text", + "content": "The University of Tokyo " + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "inline_equation", + "content": "{}^{2}" + }, + { + "bbox": [ + 53, + 167, + 555, + 223 + ], + "type": "text", + "content": "ARC Lab, Tencent PCG \nhttps://github.com/TencentARC/MasaCtrl" + } + ] + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 48, + 232, + 206, + 312 + ], + "blocks": [ + { + "bbox": [ + 48, + 232, + 206, + 312 + ], + "lines": [ + { + "bbox": [ + 48, + 232, + 206, + 312 + ], + "spans": [ + { + "bbox": [ + 48, + 232, + 206, + 312 + ], + "type": "image", + "image_path": "99d6a69dc4cce4ee20c38447e1f616a3bde67f89ed8cae7bc7e8bccf40826b33.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 59, + 314, + 116, + 324 + ], + "lines": [ + { + "bbox": [ + 59, + 314, + 116, + 324 + ], + "spans": [ + { + "bbox": [ + 59, + 314, + 116, + 324 + ], + "type": "text", + "content": "Input real image" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 208, + 232, + 365, + 312 + ], + "blocks": [ + { + "bbox": [ + 208, + 232, + 365, + 312 + ], + "lines": [ + { + "bbox": [ + 208, + 232, + 365, + 312 + ], + "spans": [ + { + "bbox": [ + 208, + 232, + 365, + 312 + ], + "type": "image", + "image_path": "36a1938290766f5b3cc7ea1bbf3369d82ba8a349d1c9022b195e9fae4e93f8d7.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 229, + 314, + 343, + 324 + ], + "lines": [ + { + "bbox": [ + 229, + 314, + 343, + 324 + ], + "spans": [ + { + "bbox": [ + 229, + 314, + 343, + 324 + ], + "type": "text", + "content": "\"A sitting boy\" " + }, + { + "bbox": [ + 229, + 314, + 343, + 324 + ], + "type": "inline_equation", + "content": "\\rightarrow" + }, + { + "bbox": [ + 229, + 314, + 343, + 324 + ], + "type": "text", + "content": " \"... standing ...\"" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 367, + 232, + 527, + 312 + ], + "blocks": [ + { + "bbox": [ + 367, + 232, + 527, + 312 + ], + "lines": [ + { + "bbox": [ + 367, + 232, + 527, + 312 + ], + "spans": [ + { + "bbox": [ + 367, + 232, + 527, + 312 + ], + "type": "image", + "image_path": "d6d8ade6f4570e9c392ff6822ca08cb9188645dd98dcf844b17bed52e4908a38.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 378, + 314, + 525, + 324 + ], + "lines": [ + { + "bbox": [ + 378, + 314, + 525, + 324 + ], + "spans": [ + { + "bbox": [ + 378, + 314, + 525, + 324 + ], + "type": "text", + "content": "Input real image \"... , giving a thumbs up\"" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 48, + 327, + 206, + 407 + ], + "blocks": [ + { + "bbox": [ + 48, + 327, + 206, + 407 + ], + "lines": [ + { + "bbox": [ + 48, + 327, + 206, + 407 + ], + "spans": [ + { + "bbox": [ + 48, + 327, + 206, + 407 + ], + "type": "image", + "image_path": "a2fb0f168cdc05bfd60ace390b4f882da4197c7f4ff0b4aae1c809b93cb40cab.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 70, + 408, + 183, + 418 + ], + "lines": [ + { + "bbox": [ + 70, + 408, + 183, + 418 + ], + "spans": [ + { + "bbox": [ + 70, + 408, + 183, + 418 + ], + "type": "text", + "content": "\"Elon Musk\" " + }, + { + "bbox": [ + 70, + 408, + 183, + 418 + ], + "type": "inline_equation", + "content": "\\rightarrow" + }, + { + "bbox": [ + 70, + 408, + 183, + 418 + ], + "type": "text", + "content": " \"... side view ...\"" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 208, + 327, + 365, + 407 + ], + "blocks": [ + { + "bbox": [ + 208, + 327, + 365, + 407 + ], + "lines": [ + { + "bbox": [ + 208, + 327, + 365, + 407 + ], + "spans": [ + { + "bbox": [ + 208, + 327, + 365, + 407 + ], + "type": "image", + "image_path": "df3b1a6b61a933b60d12f663e1aaf6d7784cb31df63436cc4915ab98b846ac7e.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 238, + 408, + 334, + 418 + ], + "lines": [ + { + "bbox": [ + 238, + 408, + 334, + 418 + ], + "spans": [ + { + "bbox": [ + 238, + 408, + 334, + 418 + ], + "type": "text", + "content": "\"An apple\" " + }, + { + "bbox": [ + 238, + 408, + 334, + 418 + ], + "type": "inline_equation", + "content": "\\rightarrow" + }, + { + "bbox": [ + 238, + 408, + 334, + 418 + ], + "type": "text", + "content": " \"Two apples\"" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 367, + 327, + 527, + 407 + ], + "blocks": [ + { + "bbox": [ + 367, + 327, + 527, + 407 + ], + "lines": [ + { + "bbox": [ + 367, + 327, + 527, + 407 + ], + "spans": [ + { + "bbox": [ + 367, + 327, + 527, + 407 + ], + "type": "image", + "image_path": "86d0cf2101bc73836e0dcc7cfb727fb0b04ff029e212fe1d32a22103e3901dc0.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 374, + 408, + 519, + 419 + ], + "lines": [ + { + "bbox": [ + 374, + 408, + 519, + 419 + ], + "spans": [ + { + "bbox": [ + 374, + 408, + 519, + 419 + ], + "type": "text", + "content": "\"A standing bird\" " + }, + { + "bbox": [ + 374, + 408, + 519, + 419 + ], + "type": "inline_equation", + "content": "\\rightarrow" + }, + { + "bbox": [ + 374, + 408, + 519, + 419 + ], + "type": "text", + "content": " \"..., spreading wings\"" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 427, + 546, + 464 + ], + "lines": [ + { + "bbox": [ + 46, + 427, + 546, + 464 + ], + "spans": [ + { + "bbox": [ + 46, + 427, + 546, + 464 + ], + "type": "text", + "content": "Figure 1: Our method MasaCtrl can perform text-based non-rigid image synthesis and real image editing without fine-tuning. Meanwhile, our method can be easily integrated into controllable diffusion models, like T2I-Adapter [17] or ControlNet [45], to perform more consistent and faithful synthesis and editing (last column)." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "bbox": [ + 143, + 474, + 192, + 487 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 474, + 192, + 487 + ], + "spans": [ + { + "bbox": [ + 143, + 474, + 192, + 487 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 46, + 500, + 289, + 693 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 500, + 289, + 693 + ], + "spans": [ + { + "bbox": [ + 46, + 500, + 289, + 693 + ], + "type": "text", + "content": "Despite the success in large-scale text-to-image generation and text-conditioned image editing, existing methods still struggle to produce consistent generation and editing results. For example, generation approaches usually fail to synthesize multiple images of the same objects/characters but with different views or poses. Meanwhile, existing editing methods either fail to achieve effective complex non-rigid editing while maintaining the overall textures and identity, or require time-consuming fine-tuning to capture the image-specific appearance. In this paper, we develop MasaCtrl, a tuning-free method to achieve consistent image generation and complex non-rigid image editing simultaneously. Specifically, MasaCtrl converts existing self-attention in diffusion models into mutual self-attention, so that it can query correlated local contents and textures from source images for consistency. To further alleviate the query" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 475, + 546, + 548 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 475, + 546, + 548 + ], + "spans": [ + { + "bbox": [ + 304, + 475, + 546, + 548 + ], + "type": "text", + "content": "confusion between foreground and background, we propose a mask-guided mutual self-attention strategy, where the mask can be easily extracted from the cross-attention maps. Extensive experiments show that the proposed MasaCtrl can produce impressive results in both consistent image generation and complex non-rigid real image editing." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 583, + 387, + 596 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 583, + 387, + 596 + ], + "spans": [ + { + "bbox": [ + 306, + 583, + 387, + 596 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "type": "text", + "content": "Recent advances in text-to-image (T2I) generation [25, 19, 41, 24, 27] have achieved great success. Those large-scale T2I models, such as Stable Diffusion [27], can generate diverse and high-quality images conforming to given text prompts. When leveraging the T2I models, we can also perform promising text-conditioned image editing [19, 10, 35, 21]. However, there is still a large gap between our needs and existing methods in terms of consistent generation and editing." + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 61, + 702, + 259, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 702, + 259, + 713 + ], + "spans": [ + { + "bbox": [ + 61, + 702, + 259, + 713 + ], + "type": "text", + "content": "*Work done during an internship at ARC Lab, Tencent PCG." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "footer", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "22560" + } + ] + } + ], + "index": 23 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 193 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 193 + ], + "type": "text", + "content": "For the text-to-image generation, we usually want to generate several images of the same objects/characters but with different views or complex non-rigid variances (e.g., the changes of posture). Such capabilities are urgently needed for creating comic books and generating short videos using existing powerful T2I image models. However, this requirement is highly challenging. Even if we fix the input random noise and use very similar prompts (e.g., 'a sitting cat' vs. 'a laying cat' shown in Fig. 2), the generated images vary in both structures and identity." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 195, + 289, + 387 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 195, + 289, + 387 + ], + "spans": [ + { + "bbox": [ + 47, + 195, + 289, + 387 + ], + "type": "text", + "content": "For text-conditioned image editing, existing methods [10, 35, 21] achieve impressive editing effects in image translation, stylization, and appearance replacement while keeping the input structure and scene layout unchanged. However, those methods usually fail to change poses or views while maintaining the overall textures and identity, leading to inconsistent editing results. The latter editing way is a more complicated non-rigid editing for practical use. Imagic [12] is then proposed to address this challenge. It allows complex non-rigid edits while preserving its original characteristics. It can make a standing dog sit down, cause a bird to spread its wings, etc. Nevertheless, it requires fine-tuning the entire T2I diffusion model and optimizing the textual embedding to capture the image-specific appearance for each edit, which is time-consuming and impractical for real-world applications." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 391, + 289, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 391, + 289, + 714 + ], + "spans": [ + { + "bbox": [ + 47, + 391, + 289, + 714 + ], + "type": "text", + "content": "In this paper, we aim to develop a tuning-free method to address the above challenges, enabling a more consistent generation of multiple images and complex non-rigid editing without fine-tuning. The core challenge is how to keep consistent. Unlike previous works [10, 21, 3] that usually operate on cross-attention in T2I models, we propose to convert existing self-attention to mutual self-attention, so that it can query correlated local structures and textures from a source image for consistency. Specifically, we first generate an image from a random (or inverted a real image) noise, resulting in the denoising process (DP1) for the source image synthesis. In the new denoising process (DP2) of generating a new image or editing an existing one, we can use the Query features in DP2 self-attention to query the corresponding Key and Value features in DP1 self-attention. In other words, we transform the existing self-attention into 'cross-attention', where the crossing operation happens in the self-attention of two related denoising processes, rather than between the U-Net features and text embeddings. We call this 'crossing self-attention as mutual self-attention. However, directly applying this strategy can only generate images almost identical to the source image and cannot comply with the target text prompt (as analyzed in Fig. 9). Thus we further control the denoising timestep and the layer position in U-Net for performing mutual self-attention to achieve consistent synthesis and editing. More analyses are in Sec. 4.1 and Sec. 5.5. In this" + } + ] + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 309, + 72, + 387, + 150 + ], + "blocks": [ + { + "bbox": [ + 309, + 72, + 387, + 150 + ], + "lines": [ + { + "bbox": [ + 309, + 72, + 387, + 150 + ], + "spans": [ + { + "bbox": [ + 309, + 72, + 387, + 150 + ], + "type": "image", + "image_path": "fc272f30003b45f0263635795511e6d1de79443672bf052a7e181bf7738f7073.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 325, + 152, + 369, + 162 + ], + "lines": [ + { + "bbox": [ + 325, + 152, + 369, + 162 + ], + "spans": [ + { + "bbox": [ + 325, + 152, + 369, + 162 + ], + "type": "text", + "content": "\"...sitting...\"" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 387, + 72, + 465, + 150 + ], + "blocks": [ + { + "bbox": [ + 387, + 72, + 465, + 150 + ], + "lines": [ + { + "bbox": [ + 387, + 72, + 465, + 150 + ], + "spans": [ + { + "bbox": [ + 387, + 72, + 465, + 150 + ], + "type": "image", + "image_path": "13b42cee5fcc9c21834f61e69a72c2e5def9b65c41afd253f7206ef2422a7ac7.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 404, + 152, + 447, + 162 + ], + "lines": [ + { + "bbox": [ + 404, + 152, + 447, + 162 + ], + "spans": [ + { + "bbox": [ + 404, + 152, + 447, + 162 + ], + "type": "text", + "content": "...laying..." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 466, + 72, + 544, + 150 + ], + "blocks": [ + { + "bbox": [ + 466, + 72, + 544, + 150 + ], + "lines": [ + { + "bbox": [ + 466, + 72, + 544, + 150 + ], + "spans": [ + { + "bbox": [ + 466, + 72, + 544, + 150 + ], + "type": "image", + "image_path": "4151ff38d4a99988f706d898202954d7e4e915f7a7305ae4b1f1a57537a31a0b.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 471, + 152, + 539, + 162 + ], + "lines": [ + { + "bbox": [ + 471, + 152, + 539, + 162 + ], + "spans": [ + { + "bbox": [ + 471, + 152, + 539, + 162 + ], + "type": "text", + "content": "...laying...\" (Ours)" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 308, + 163, + 387, + 242 + ], + "blocks": [ + { + "bbox": [ + 308, + 163, + 387, + 242 + ], + "lines": [ + { + "bbox": [ + 308, + 163, + 387, + 242 + ], + "spans": [ + { + "bbox": [ + 308, + 163, + 387, + 242 + ], + "type": "image", + "image_path": "0f6bd7f93692c214017a6e8fa521850b6cd5381e84aed7e17a7694039bf03c1b.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 335, + 245, + 359, + 253 + ], + "lines": [ + { + "bbox": [ + 335, + 245, + 359, + 253 + ], + "spans": [ + { + "bbox": [ + 335, + 245, + 359, + 253 + ], + "type": "text", + "content": "Source" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 387, + 163, + 465, + 242 + ], + "blocks": [ + { + "bbox": [ + 387, + 163, + 465, + 242 + ], + "lines": [ + { + "bbox": [ + 387, + 163, + 465, + 242 + ], + "spans": [ + { + "bbox": [ + 387, + 163, + 465, + 242 + ], + "type": "image", + "image_path": "0c9714560e8b87a6d2d166223941d717cfaf04ef2d73a8244ecece4f373ef1fc.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 394, + 245, + 459, + 254 + ], + "lines": [ + { + "bbox": [ + 394, + 245, + 459, + 254 + ], + "spans": [ + { + "bbox": [ + 394, + 245, + 459, + 254 + ], + "type": "text", + "content": "w/o mask guidance" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 466, + 163, + 544, + 242 + ], + "blocks": [ + { + "bbox": [ + 466, + 163, + 544, + 242 + ], + "lines": [ + { + "bbox": [ + 466, + 163, + 544, + 242 + ], + "spans": [ + { + "bbox": [ + 466, + 163, + 544, + 242 + ], + "type": "image", + "image_path": "dda00ec7413d8f0ce4e2ad05618ad2f298cce5311fd424672db1d89929449c19.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 471, + 245, + 539, + 254 + ], + "lines": [ + { + "bbox": [ + 471, + 245, + 539, + 254 + ], + "spans": [ + { + "bbox": [ + 471, + 245, + 539, + 254 + ], + "type": "text", + "content": "with mask guidance" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 305, + 264, + 545, + 312 + ], + "lines": [ + { + "bbox": [ + 305, + 264, + 545, + 312 + ], + "spans": [ + { + "bbox": [ + 305, + 264, + 545, + 312 + ], + "type": "text", + "content": "Figure 2: First row: images synthesized from fixed random seed (middle, changed identity) and our method (right, maintained identity). Second row: image synthesized without mask guidance (middle) and with mask guidance (right)." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 326, + 545, + 397 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 326, + 545, + 397 + ], + "spans": [ + { + "bbox": [ + 305, + 326, + 545, + 397 + ], + "type": "text", + "content": "way, we can use contents in the source image as the generation material to better maintain the texture and identity. Meanwhile, its structure, pose, and non-rigid variances can be controlled by target text prompt, and guided by recent controllable T2I-Adapters [17] or ControlNet [45]. Fig. 1 shows some synthesis and editing examples." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 399, + 546, + 591 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 399, + 546, + 591 + ], + "spans": [ + { + "bbox": [ + 304, + 399, + 546, + 591 + ], + "type": "text", + "content": "The proposed mutual self-attention control can work well for images with disentangled foreground and background, but may fail in the synthesis and editing process where the foreground and background have similar patterns and colors. In these cases, mutual self-attention tends to confuse the foreground and background, leading to a messy result (2nd row in Fig. 2). To address this problem, we further propose a mask-guided mutual self-attention. Specifically, we first utilize the cross attention in T2I diffusion models to extract a mask associated with the main object in the image. This mask can successfully separate foreground and background, and restrict the target foreground/background features to query only foreground/background features of the source image, respectively. Such an operation can effectively alleviate the query confusion between the foreground and background." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 594, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 547, + 714 + ], + "type": "text", + "content": "Our contributions can be summarized as follows. 1) We propose a tuning-free method, namely, MasaCtrl, to simultaneously achieve consistent image synthesis and complex non-rigid image editing. 2) An effective mutual self-attention mechanism with delicate designs is proposed to change pose, view, structures, and non-rigid variances while maintaining the characteristics, texture, and identity. 3) To alleviate the query confusion between foreground and background, we further propose a masked-guided mutual self-attention, where the mask can be easily computed from the" + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "22561" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 109 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 109 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 109 + ], + "type": "text", + "content": "cross-attentions. 4) Experimental results have shown the effectiveness of our proposed MasaCtrl in both consistent image generation and complex non-rigid real image editing." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 120, + 134, + 132 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 120, + 134, + 132 + ], + "spans": [ + { + "bbox": [ + 47, + 120, + 134, + 132 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 140, + 191, + 153 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 140, + 191, + 153 + ], + "spans": [ + { + "bbox": [ + 47, + 140, + 191, + 153 + ], + "type": "text", + "content": "2.1. Text-to-Image Generation" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 159, + 289, + 435 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 159, + 289, + 435 + ], + "spans": [ + { + "bbox": [ + 46, + 159, + 289, + 435 + ], + "type": "text", + "content": "Early image generation methods conditioned on text description mainly based on GANs [26, 43, 44, 39, 14, 2, 46, 40, 42, 34], due to their powerful capability of high-fidelity image synthesis. These models try to align the text descriptions and synthesized image contents via multimodal vision-language learning and have achieved cheerful synthesis results on domain-specific datasets. Text-to-image generation with auto-regressive and diffusion models has obtained impressive diversity results. DALL-E [25], CogView [6] and Parti [41], large-scale text-to-image models trained with a large amount of data, enable generating images from open-domain text descriptions. However, the auto-regressive generation nature leads to the slow generation process defect. Most recently, diffusion models [32, 11, 20, 5] have shown superior generative power and achieved state-of-the-art synthesis results in terms of image quality and diversity than previous GAN-based and auto-regressive image generation models. By conditioning the text prompt into the diffusion model, various text-to-image diffusion models GLIDE [19], VQ-Diffusion [8], LDM [27], DALL-E 2 [24], and Imagen [30] have been developed. They can synthesize high-quality images that highly comply with the given text description." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 443, + 197, + 456 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 443, + 197, + 456 + ], + "spans": [ + { + "bbox": [ + 47, + 443, + 197, + 456 + ], + "type": "text", + "content": "2.2. Text-guided Image Editing." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 462, + 287, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 462, + 287, + 594 + ], + "spans": [ + { + "bbox": [ + 46, + 462, + 287, + 594 + ], + "type": "text", + "content": "Text-guided image editing is a challenging task that aims to manipulate images according to natural language descriptions. Previous methods based on generative adversarial networks (GANs) [18, 15, 38, 22] have achieved some success on domain-specific datasets (e.g., face datasets), but they have limited applicability and generality. A recent approach based on auto-regressive models, VQGAN-CLIP [4], combines VQGAN [7] and CLIP [23] to produce high-quality images and precise edits with diverse and controllable results. However, this approach suffers from slow generation speed and high computational cost." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": "Different from previous methods based on GANs or auto-regressive models, diffusion models offer a fast and efficient way to synthesize and edit images conditioned on text prompts. However, existing diffusion-based methods have some limitations regarding local and global editing. For example, the works [19, 1] require extra masks to edit local regions of the image; [13] can edit global aspects of the image by changing the text prompt directly, but cannot modify local details; [10, 35] use cross-attention or spatial features to edit both global and local aspects of the image" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 240 + ], + "type": "text", + "content": "by changing the text prompt directly. Still, they tend to preserve the original layout of the source image and fail to handle non-rigid transformations (e.g., changing object pose). In contrast, we propose a novel approach that leverages the self-attention mechanism to achieve consistent and complex non-rigid image synthesis and editing. Our approach can modify various object attributes (e.g., pose, shape) by changing the text prompt accordingly. The most related work to ours is Imagic [12], which also enables various prompt-based non-rigid image editing. However, unlike our approach can edit images on the fly, Imagic requires careful optimization of the textual embedding and fine-tuning of the model, which is time-consuming and unfriendly for ordinary users." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 252, + 391, + 265 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 252, + 391, + 265 + ], + "spans": [ + { + "bbox": [ + 306, + 252, + 391, + 265 + ], + "type": "text", + "content": "3. Preliminaries" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 272, + 443, + 285 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 272, + 443, + 285 + ], + "spans": [ + { + "bbox": [ + 306, + 272, + 443, + 285 + ], + "type": "text", + "content": "3.1. Latent Diffusion Models" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "spans": [ + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "type": "text", + "content": "Diffusion models [11, 31, 20] are generative models that can synthesize desired data samples from Gaussian noise via iterative denoising. Our method is based on the recent state-of-the-art text-conditioned model Stable Diffusion (SD) [27], which performs the diffusion-denoising process in the latent rather than image space. Specifically, a pretrained image autoencoder first encodes the image " + }, + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "type": "text", + "content": " into latent representations " + }, + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "type": "text", + "content": ". Then the denoising network " + }, + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "type": "inline_equation", + "content": "\\epsilon_{\\theta}" + }, + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "type": "text", + "content": " (a time-conditional U-Net [28]) is trained in this latent space. After being trained, we can sample a random noise " + }, + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "type": "inline_equation", + "content": "z_{T} \\sim \\mathcal{N}(0,1)" + }, + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "type": "text", + "content": " and perform the latent denoising process. The denoised latent representation " + }, + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "type": "inline_equation", + "content": "z_{0}" + }, + { + "bbox": [ + 304, + 291, + 547, + 448 + ], + "type": "text", + "content": " can be decoded into an image using the pretrained autoencoder." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 456, + 520, + 468 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 456, + 520, + 468 + ], + "spans": [ + { + "bbox": [ + 306, + 456, + 520, + 468 + ], + "type": "text", + "content": "3.2. Attention Mechanism in Stable Diffusion" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "spans": [ + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "type": "text", + "content": "The denoising U-Net " + }, + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "type": "inline_equation", + "content": "\\epsilon_{\\theta}" + }, + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "type": "text", + "content": " in the SD model, consists of a series of basic blocks, and each basic block contains a residual block [9], a self-attention module, and a cross-attention [36] module. At denoising step " + }, + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "type": "text", + "content": ", the features from the previous " + }, + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "type": "inline_equation", + "content": "(l - 1)" + }, + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "type": "text", + "content": "-th basic block first pass through the residual block to generate intermediate features " + }, + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "type": "inline_equation", + "content": "f_{t}^{l}" + }, + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "type": "text", + "content": "; then they are reorganized by the self-attention layer, and receive textual information from the text prompt " + }, + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 304, + 475, + 547, + 594 + ], + "type": "text", + "content": " by the following cross-attention layer. The attention mechanism can be formulated as follows:" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 340, + 602, + 545, + 630 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 340, + 602, + 545, + 630 + ], + "spans": [ + { + "bbox": [ + 340, + 602, + 545, + 630 + ], + "type": "interline_equation", + "content": "\\operatorname {A t t e n t i o n} (Q, K, V) = \\operatorname {S o f t m a x} \\left(\\frac {Q K ^ {T}}{\\sqrt {d}}\\right) V, \\tag {1}", + "image_path": "561956c7d4865df1de3fcdfe55b14e2c91dae35c3783bf54daacbbdd8a43aefe.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 638, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 638, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 638, + 547, + 715 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 638, + 547, + 715 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 304, + 638, + 547, + 715 + ], + "type": "text", + "content": " is the query features projected from the spatial features, and " + }, + { + "bbox": [ + 304, + 638, + 547, + 715 + ], + "type": "inline_equation", + "content": "K, V" + }, + { + "bbox": [ + 304, + 638, + 547, + 715 + ], + "type": "text", + "content": " are the key and value features projected from the spatial features (in self-attention layers) or the textual embedding (in cross-attention layers) with corresponding projection matrices. " + }, + { + "bbox": [ + 304, + 638, + 547, + 715 + ], + "type": "inline_equation", + "content": "A = \\operatorname{Softmax}\\left(\\frac{QK^T}{\\sqrt{d}}\\right)" + }, + { + "bbox": [ + 304, + 638, + 547, + 715 + ], + "type": "text", + "content": " is the attention map used to aggregate the value " + }, + { + "bbox": [ + 304, + 638, + 547, + 715 + ], + "type": "inline_equation", + "content": "V" + }, + { + "bbox": [ + 304, + 638, + 547, + 715 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 733, + 318, + 742 + ], + "type": "footer", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 733, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 733, + 318, + 742 + ], + "type": "text", + "content": "22562" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 70, + 541, + 293 + ], + "blocks": [ + { + "bbox": [ + 51, + 70, + 541, + 293 + ], + "lines": [ + { + "bbox": [ + 51, + 70, + 541, + 293 + ], + "spans": [ + { + "bbox": [ + 51, + 70, + 541, + 293 + ], + "type": "image", + "image_path": "544b0184a63e05419f081618b6a5d83cbbdb4c6fcb88d7b76308dc53997e26b1.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 301, + 547, + 351 + ], + "lines": [ + { + "bbox": [ + 46, + 301, + 547, + 351 + ], + "spans": [ + { + "bbox": [ + 46, + 301, + 547, + 351 + ], + "type": "text", + "content": "Figure 3: Pipeline of the proposed MasaCtrl. Our method tries to perform complex non-rigid image editing and synthesize content-consistent images. The source image is either real or synthesized with source text prompt " + }, + { + "bbox": [ + 46, + 301, + 547, + 351 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 46, + 301, + 547, + 351 + ], + "type": "text", + "content": ". During the denoising process for image synthesis, we convert the self-attention into mutual self-attention to query image contents from source image " + }, + { + "bbox": [ + 46, + 301, + 547, + 351 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 46, + 301, + 547, + 351 + ], + "type": "text", + "content": ", so that we can synthesize content-consist images under the modified target prompt " + }, + { + "bbox": [ + 46, + 301, + 547, + 351 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 46, + 301, + 547, + 351 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 371, + 289, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 371, + 289, + 601 + ], + "spans": [ + { + "bbox": [ + 46, + 371, + 289, + 601 + ], + "type": "text", + "content": "These attention layers in the SD model contain much information for the overall structure/layout and content formation of the synthesized image [10, 35]. The internal cross-attention maps are high-dimensional tensors that bind the spatial pixels and textual embedding [10], and they are explored for image editing [10] and faithful image synthesis [3]. In addition, the features in the self-attention layer are employed as plug-and-play features to be injected into specified U-Net layers to perform image translation. However, these controls cannot perform non-rigid editing (e.g., pose change) since they maintain the semantic layout and structures. Inspired by the phenomenon that performing self-attention across batches can generate similar image contents, which is also observed in Tune-A-Video [37], we adapt the self-attention mechanism in the T2I model to query contents from source images with delicate designs. Thus we can perform consistent synthesis and non-rigid editing that change the layout and structure of the source image while preserving image contents." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 609, + 285, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 609, + 285, + 624 + ], + "spans": [ + { + "bbox": [ + 47, + 609, + 285, + 624 + ], + "type": "text", + "content": "4. Tuning-Free Mutual Self-Attention Control" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": "Given a source image " + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": " and the corresponding text prompt " + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": ", our goal is to synthesize the desired image " + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": " that complies with the target edited text prompt " + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": " (directly modified from " + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": "). Note that the edited target image " + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": " is spatially edited from " + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": " and should preserve the object contents (e.g., textures and identity) in " + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": ". For instance, consider a photo (corresponding to " + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 46, + 630, + 288, + 715 + ], + "type": "text", + "content": ") where a dog is sitting," + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 371, + 545, + 407 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 371, + 545, + 407 + ], + "spans": [ + { + "bbox": [ + 304, + 371, + 545, + 407 + ], + "type": "text", + "content": "and we want the dog to be in the running pose with the edited text prompt " + }, + { + "bbox": [ + 304, + 371, + 545, + 407 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 304, + 371, + 545, + 407 + ], + "type": "text", + "content": " that adds the 'running' into the source prompt " + }, + { + "bbox": [ + 304, + 371, + 545, + 407 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 304, + 371, + 545, + 407 + ], + "type": "text", + "content": " (see Fig. 3)." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "spans": [ + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "type": "text", + "content": "Our core idea is to combine the semantic layout synthesized with the target prompt " + }, + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "type": "text", + "content": " and the contents in the source image " + }, + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "type": "text", + "content": " to synthesize the desired image " + }, + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "type": "text", + "content": ". To achieve so, we propose MasaCtrl, which adapts the self-attention mechanism in the SD model into a crossing one to query semantically similar contents from the source image. Consequently, the target image " + }, + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "type": "text", + "content": " can be synthesized by querying the contents from " + }, + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 304, + 408, + 546, + 587 + ], + "type": "text", + "content": " with the modified self-attention mechanism during the denoising process. We can achieve so for the following reasons: 1) the image layout is formed in the early denoising steps (shown in Fig. 4(a)); 2) in addition, as shown in Fig. 4(b), the encoded query features in the self-attention layer are semantically corresponded (e.g., the horses are in the same color), thus one can query content information from another." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 589, + 547, + 662 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 589, + 547, + 662 + ], + "spans": [ + { + "bbox": [ + 304, + 589, + 547, + 662 + ], + "type": "text", + "content": "The overall architecture of the proposed pipeline to perform synthesis and editing is shown in Fig. 3, and the algorithm is summarized in Alg. 1. The input source image " + }, + { + "bbox": [ + 304, + 589, + 547, + 662 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 304, + 589, + 547, + 662 + ], + "type": "text", + "content": " is either a real image or a generated one from the SD model with text prompt " + }, + { + "bbox": [ + 304, + 589, + 547, + 662 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 304, + 589, + 547, + 662 + ], + "type": "text", + "content": ". During each denoising step " + }, + { + "bbox": [ + 304, + 589, + 547, + 662 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 589, + 547, + 662 + ], + "type": "text", + "content": " of synthesizing target image " + }, + { + "bbox": [ + 304, + 589, + 547, + 662 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 304, + 589, + 547, + 662 + ], + "type": "text", + "content": ", we assemble the inputs of" + } + ] + } + ], + "index": 7 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "type": "text", + "content": "1When " + }, + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "type": "text", + "content": " is a real image, we set the text prompt " + }, + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "type": "text", + "content": " as null and utilize the deterministic DDIM inversion [31] to obtain the initial noise map. When " + }, + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "type": "text", + "content": " is an image synthesized with prompt " + }, + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "type": "text", + "content": ", the initial noise map is the same as the one used to synthesize " + }, + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 305, + 673, + 547, + 713 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "22563" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 94 + ], + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 94 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 94 + ], + "type": "text", + "content": "Algorithm 1 MasaCtrl: Tuning-Free Mutual Self-Attention Control" + } + ] + } + ], + "index": 0, + "type": "text" + }, + { + "bbox": [ + 47, + 95, + 286, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 95, + 286, + 120 + ], + "spans": [ + { + "bbox": [ + 47, + 95, + 286, + 120 + ], + "type": "text", + "content": "Input: A source prompt " + }, + { + "bbox": [ + 47, + 95, + 286, + 120 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 47, + 95, + 286, + 120 + ], + "type": "text", + "content": ", a modified prompt " + }, + { + "bbox": [ + 47, + 95, + 286, + 120 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 47, + 95, + 286, + 120 + ], + "type": "text", + "content": ", the source and target initial latent noise maps " + }, + { + "bbox": [ + 47, + 95, + 286, + 120 + ], + "type": "inline_equation", + "content": "z_{T}^{s}" + }, + { + "bbox": [ + 47, + 95, + 286, + 120 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 95, + 286, + 120 + ], + "type": "inline_equation", + "content": "z_{T}" + }, + { + "bbox": [ + 47, + 95, + 286, + 120 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 120, + 286, + 142 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 120, + 286, + 142 + ], + "spans": [ + { + "bbox": [ + 47, + 120, + 286, + 142 + ], + "type": "text", + "content": "Output: Latent map " + }, + { + "bbox": [ + 47, + 120, + 286, + 142 + ], + "type": "inline_equation", + "content": "z_0^s" + }, + { + "bbox": [ + 47, + 120, + 286, + 142 + ], + "type": "text", + "content": ", edited latent map " + }, + { + "bbox": [ + 47, + 120, + 286, + 142 + ], + "type": "inline_equation", + "content": "z_0" + }, + { + "bbox": [ + 47, + 120, + 286, + 142 + ], + "type": "text", + "content": " corresponding to " + }, + { + "bbox": [ + 47, + 120, + 286, + 142 + ], + "type": "inline_equation", + "content": "P_s" + }, + { + "bbox": [ + 47, + 120, + 286, + 142 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 120, + 286, + 142 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 47, + 120, + 286, + 142 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 54, + 145, + 282, + 239 + ], + "type": "list", + "angle": 0, + "index": 11, + "blocks": [ + { + "bbox": [ + 54, + 145, + 170, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 145, + 170, + 156 + ], + "spans": [ + { + "bbox": [ + 54, + 145, + 170, + 156 + ], + "type": "text", + "content": "1: for " + }, + { + "bbox": [ + 54, + 145, + 170, + 156 + ], + "type": "inline_equation", + "content": "t = T, T - 1, \\ldots, 1" + }, + { + "bbox": [ + 54, + 145, + 170, + 156 + ], + "type": "text", + "content": " do" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 54, + 157, + 211, + 169 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 157, + 211, + 169 + ], + "spans": [ + { + "bbox": [ + 54, + 157, + 211, + 169 + ], + "type": "text", + "content": "2: " + }, + { + "bbox": [ + 54, + 157, + 211, + 169 + ], + "type": "inline_equation", + "content": "\\epsilon_s, \\{Q_s, K_s, V_s\\} \\gets \\epsilon_\\theta(z_t^s, P_s, t)" + }, + { + "bbox": [ + 54, + 157, + 211, + 169 + ], + "type": "text", + "content": ";" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 54, + 170, + 173, + 181 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 170, + 173, + 181 + ], + "spans": [ + { + "bbox": [ + 54, + 170, + 173, + 181 + ], + "type": "text", + "content": "3: " + }, + { + "bbox": [ + 54, + 170, + 173, + 181 + ], + "type": "inline_equation", + "content": "z_{t - 1}^{s}\\gets \\mathrm{Sample}(z_{t}^{s},\\epsilon_{s})" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 54, + 181, + 182, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 181, + 182, + 193 + ], + "spans": [ + { + "bbox": [ + 54, + 181, + 182, + 193 + ], + "type": "text", + "content": "4: " + }, + { + "bbox": [ + 54, + 181, + 182, + 193 + ], + "type": "inline_equation", + "content": "\\{Q,K,V\\} \\gets \\epsilon_{\\theta}(z_t,P,t)" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 54, + 193, + 282, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 193, + 282, + 205 + ], + "spans": [ + { + "bbox": [ + 54, + 193, + 282, + 205 + ], + "type": "text", + "content": "5: " + }, + { + "bbox": [ + 54, + 193, + 282, + 205 + ], + "type": "inline_equation", + "content": "\\{Q^{*},K^{*},V^{*}\\} \\leftarrow" + }, + { + "bbox": [ + 54, + 193, + 282, + 205 + ], + "type": "text", + "content": " EDIT(" + }, + { + "bbox": [ + 54, + 193, + 282, + 205 + ], + "type": "inline_equation", + "content": "\\{Q,K,V\\},\\{Q_{s},K_{s},V_{s}\\}" + }, + { + "bbox": [ + 54, + 193, + 282, + 205 + ], + "type": "text", + "content": ");" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 54, + 205, + 203, + 217 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 205, + 203, + 217 + ], + "spans": [ + { + "bbox": [ + 54, + 205, + 203, + 217 + ], + "type": "text", + "content": "6: " + }, + { + "bbox": [ + 54, + 205, + 203, + 217 + ], + "type": "inline_equation", + "content": "\\epsilon = \\epsilon_{\\theta}(z_t,P,t;\\{Q^*,K^*,V^*\\})" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 54, + 218, + 167, + 229 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 218, + 167, + 229 + ], + "spans": [ + { + "bbox": [ + 54, + 218, + 167, + 229 + ], + "type": "text", + "content": "7: " + }, + { + "bbox": [ + 54, + 218, + 167, + 229 + ], + "type": "inline_equation", + "content": "z_{t - 1}\\gets \\mathrm{Sample}(z_t,\\epsilon);" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 54, + 230, + 97, + 239 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 230, + 97, + 239 + ], + "spans": [ + { + "bbox": [ + 54, + 230, + 97, + 239 + ], + "type": "text", + "content": "8: end for" + } + ] + } + ], + "index": 10 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 48, + 243, + 105, + 255 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 243, + 105, + 255 + ], + "spans": [ + { + "bbox": [ + 48, + 243, + 105, + 255 + ], + "type": "text", + "content": "Return " + }, + { + "bbox": [ + 48, + 243, + 105, + 255 + ], + "type": "inline_equation", + "content": "z_0^s, z_0" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 47, + 278, + 286, + 337 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 278, + 286, + 337 + ], + "spans": [ + { + "bbox": [ + 47, + 278, + 286, + 337 + ], + "type": "text", + "content": "the self-attention by 1) keeping the current Query features " + }, + { + "bbox": [ + 47, + 278, + 286, + 337 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 47, + 278, + 286, + 337 + ], + "type": "text", + "content": " unchanged, and 2) obtaining the Key and Value features " + }, + { + "bbox": [ + 47, + 278, + 286, + 337 + ], + "type": "inline_equation", + "content": "K_{s}" + }, + { + "bbox": [ + 47, + 278, + 286, + 337 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 278, + 286, + 337 + ], + "type": "inline_equation", + "content": "V_{s}" + }, + { + "bbox": [ + 47, + 278, + 286, + 337 + ], + "type": "text", + "content": " from the self-attention layer in the process of synthesizing source image " + }, + { + "bbox": [ + 47, + 278, + 286, + 337 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 47, + 278, + 286, + 337 + ], + "type": "text", + "content": ". We dub this strategy mutual self-attention, and more details are in Sec. 4.1." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 338, + 286, + 433 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 338, + 286, + 433 + ], + "spans": [ + { + "bbox": [ + 46, + 338, + 286, + 433 + ], + "type": "text", + "content": "Meanwhile, we also observe the edited image often suffers from the problem of confusion between the foreground objects and background. Thus, we propose a mask-aware mutual self-attention strategy guided by the masks obtained from the cross-attention mechanism. The object mask is automatically generated from the cross-attention maps of the text token associated with the foreground object. Please refer to Sec. 4.2 for more details." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 46, + 434, + 286, + 506 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 434, + 286, + 506 + ], + "spans": [ + { + "bbox": [ + 46, + 434, + 286, + 506 + ], + "type": "text", + "content": "In addition, since the edited prompt " + }, + { + "bbox": [ + 46, + 434, + 286, + 506 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 46, + 434, + 286, + 506 + ], + "type": "text", + "content": " may not yield desired spatial layouts due to the inner limitations of the SD model, MasaCtrl can be easily integrated into existing controllable image synthesis method (e.g., T2I-Adapter [17] and ControlNet [45]) for more faithful non-rigid image editing. Please refer to Sec. 4.3 for more details." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 47, + 514, + 173, + 526 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 514, + 173, + 526 + ], + "spans": [ + { + "bbox": [ + 47, + 514, + 173, + 526 + ], + "type": "text", + "content": "4.1. Mutual Self-Attention" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "spans": [ + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "text", + "content": "As shown in the left part of Fig. 5(a), at denoising step " + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "text", + "content": " and layer " + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "text", + "content": ", the query features are defined as the projected query features " + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "inline_equation", + "content": "Q^l" + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "text", + "content": " in the self-attention module, and the content features are the key features " + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "inline_equation", + "content": "K_s^l" + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "text", + "content": " and value features " + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "inline_equation", + "content": "V_s^l" + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "text", + "content": " from the corresponding self-attention layer in the process of reconstructing the source image " + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "inline_equation", + "content": "I_s" + }, + { + "bbox": [ + 46, + 533, + 286, + 628 + ], + "type": "text", + "content": ". After that, we perform attention according to Eq. 1 to aggregate the contents from the source image." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 46, + 630, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 630, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 630, + 286, + 713 + ], + "type": "text", + "content": "However, intuitively performing such attention on all layers among all denoising steps will result in a failed image " + }, + { + "bbox": [ + 46, + 630, + 286, + 713 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 630, + 286, + 713 + ], + "type": "text", + "content": " that is nearly the same as the reconstructed image " + }, + { + "bbox": [ + 46, + 630, + 286, + 713 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 46, + 630, + 286, + 713 + ], + "type": "text", + "content": ". We argue the reason is that performing self-attention control in the early steps can disrupt the layout formation of the target image. In the premature denoising steps, the target image layout has not yet been formed (shown in Fig. 4(a))." + } + ] + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 309, + 71, + 543, + 148 + ], + "blocks": [ + { + "bbox": [ + 309, + 71, + 543, + 148 + ], + "lines": [ + { + "bbox": [ + 309, + 71, + 543, + 148 + ], + "spans": [ + { + "bbox": [ + 309, + 71, + 543, + 148 + ], + "type": "image", + "image_path": "8104f59f1e064b84f081b37a5ff4c779c280e77a747a173fa51b79500b78ba98.jpg" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 348, + 147, + 513, + 157 + ], + "lines": [ + { + "bbox": [ + 348, + 147, + 513, + 157 + ], + "spans": [ + { + "bbox": [ + 348, + 147, + 513, + 157 + ], + "type": "text", + "content": "(a) Intermediate results in denoising process" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_caption" + } + ], + "index": 19 + }, + { + "type": "image", + "bbox": [ + 321, + 158, + 543, + 247 + ], + "blocks": [ + { + "bbox": [ + 321, + 158, + 543, + 247 + ], + "lines": [ + { + "bbox": [ + 321, + 158, + 543, + 247 + ], + "spans": [ + { + "bbox": [ + 321, + 158, + 543, + 247 + ], + "type": "image", + "image_path": "5fd292d44cab9e25505b8168b7eb06ccfdf0336af66d0339a21081731ef43180.jpg" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 373, + 248, + 489, + 259 + ], + "lines": [ + { + "bbox": [ + 373, + 248, + 489, + 259 + ], + "spans": [ + { + "bbox": [ + 373, + 248, + 489, + 259 + ], + "type": "text", + "content": "(b) Query feature visualization" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 304, + 268, + 545, + 317 + ], + "lines": [ + { + "bbox": [ + 304, + 268, + 545, + 317 + ], + "spans": [ + { + "bbox": [ + 304, + 268, + 545, + 317 + ], + "type": "text", + "content": "Figure 4: (a) The intermediate results during the iterative denoising process, and (b) visualization of the projected Query features " + }, + { + "bbox": [ + 304, + 268, + 545, + 317 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 304, + 268, + 545, + 317 + ], + "type": "text", + "content": " in the self-attention layers of the U-Net at the 15th sampling step." + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_caption" + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 339, + 545, + 399 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 339, + 545, + 399 + ], + "spans": [ + { + "bbox": [ + 304, + 339, + 545, + 399 + ], + "type": "text", + "content": "We further observe the Query features in the shallow layers of U-Net (e.g., encoder part) cannot obtain clear layout and structure corresponding to the modified prompt (shown in Fig. 4(b)). Thus we cannot obtain the image with the desired spatial layout." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 304, + 403, + 545, + 510 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 403, + 545, + 510 + ], + "spans": [ + { + "bbox": [ + 304, + 403, + 545, + 510 + ], + "type": "text", + "content": "Therefore, we propose to control the mutual self-attention only in the decoder part of the " + }, + { + "bbox": [ + 304, + 403, + 545, + 510 + ], + "type": "inline_equation", + "content": "U" + }, + { + "bbox": [ + 304, + 403, + 545, + 510 + ], + "type": "text", + "content": "-Net after several denoising steps, due to the formed clear target image layout and semantically similar features (see Fig. 4). We can change the original layout into the target one with edited prompt " + }, + { + "bbox": [ + 304, + 403, + 545, + 510 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 304, + 403, + 545, + 510 + ], + "type": "text", + "content": " and keep the main objects unchanged with proper starting denoising step " + }, + { + "bbox": [ + 304, + 403, + 545, + 510 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 304, + 403, + 545, + 510 + ], + "type": "text", + "content": " and layer " + }, + { + "bbox": [ + 304, + 403, + 545, + 510 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 304, + 403, + 545, + 510 + ], + "type": "text", + "content": " for synthesis and editing. Thus the EDIT function in Alg. 1 can be formulated as follows:" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 524, + 545, + 566 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 524, + 545, + 566 + ], + "spans": [ + { + "bbox": [ + 307, + 524, + 545, + 566 + ], + "type": "interline_equation", + "content": "\\operatorname {E D I T} := \\left\\{ \\begin{array}{l l} \\left\\{Q, K _ {s}, V _ {s} \\right\\}, & \\text {i f} \\quad T - t > S \\quad \\text {a n d} \\quad l > L, \\\\ \\left\\{Q, K, V \\right\\}, & \\text {o t h e r w i s e ,} \\end{array} \\right. \\tag {2}", + "image_path": "a308ccc296aca58562d8a7ebb44abbea78c14abef4a9fa474b5500b82c4b89cc.jpg" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 304, + 566, + 544, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 566, + 544, + 590 + ], + "spans": [ + { + "bbox": [ + 304, + 566, + 544, + 590 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 566, + 544, + 590 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 304, + 566, + 544, + 590 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 566, + 544, + 590 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 304, + 566, + 544, + 590 + ], + "type": "text", + "content": " are the timestep and layer index to start attention control, respectively. " + }, + { + "bbox": [ + 304, + 566, + 544, + 590 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 304, + 566, + 544, + 590 + ], + "type": "text", + "content": " is the total denoising steps." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "text", + "content": "In the early steps, the composition and shape of the object can be roughly generated, complying with the target prompt " + }, + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "text", + "content": ". Then the content information from the source image " + }, + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "text", + "content": " is queried by the mutual self-attention mechanism to fill the generated layout of target image " + }, + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "text", + "content": ". After iterative denoising, we can obtain the synthesized image with similar contents in the source image and structure of " + }, + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "inline_equation", + "content": "I^{*}" + }, + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "text", + "content": " that complied with the input prompt. Note that our algorithm does not require fine-tuning or optimization, bringing many conveniences for ordinary users for content creation." + } + ] + } + ], + "index": 28 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 733, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 733, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 733, + 317, + 742 + ], + "type": "text", + "content": "22564" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 70, + 286, + 183 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 286, + 183 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 286, + 183 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 286, + 183 + ], + "type": "image", + "image_path": "8e1baa964161870e1099e38361e2c753df020ba7575ab50b8336fd28cd4faca4.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 107, + 185, + 229, + 196 + ], + "lines": [ + { + "bbox": [ + 107, + 185, + 229, + 196 + ], + "spans": [ + { + "bbox": [ + 107, + 185, + 229, + 196 + ], + "type": "text", + "content": "(a) Mutual self-attention control" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 51, + 201, + 284, + 319 + ], + "blocks": [ + { + "bbox": [ + 51, + 201, + 284, + 319 + ], + "lines": [ + { + "bbox": [ + 51, + 201, + 284, + 319 + ], + "spans": [ + { + "bbox": [ + 51, + 201, + 284, + 319 + ], + "type": "image", + "image_path": "a9305591d9c94c8220f85a9113f75708751b2136a6be26cc40629e355473ded0.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 80, + 321, + 254, + 332 + ], + "lines": [ + { + "bbox": [ + 80, + 321, + 254, + 332 + ], + "spans": [ + { + "bbox": [ + 80, + 321, + 254, + 332 + ], + "type": "text", + "content": "(b) Mask extraction from cross-attention maps" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 340, + 287, + 389 + ], + "lines": [ + { + "bbox": [ + 46, + 340, + 287, + 389 + ], + "spans": [ + { + "bbox": [ + 46, + 340, + 287, + 389 + ], + "type": "text", + "content": "Figure 5: (a) The mutual self-attention mechanism and control strategy in the decoder part of denoising U-Net to query contents from the source image; and (b) mask extraction strategy from cross-attention maps." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 416, + 240, + 428 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 416, + 240, + 428 + ], + "spans": [ + { + "bbox": [ + 47, + 416, + 240, + 428 + ], + "type": "text", + "content": "4.2. Mask-Guided Mutual Self-Attention" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 442, + 287, + 574 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 442, + 287, + 574 + ], + "spans": [ + { + "bbox": [ + 46, + 442, + 287, + 574 + ], + "type": "text", + "content": "We also observed the above synthesis/editing would fail when the object and background are too similar to be confused. One feasible way to tackle this problem is to segment the image into the foreground and background parts and query contents only from the corresponding parts. Inspired by previous work [10, 33], the cross-attention maps correlating to the prompt tokens contain most information of the shape and structure. Therefore, we utilize the semantic cross-attention maps to create a mask to distinguish the foreground and background in both source and target images " + }, + { + "bbox": [ + 46, + 442, + 287, + 574 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 46, + 442, + 287, + 574 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 442, + 287, + 574 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 442, + 287, + 574 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "content": "Specifically, at step " + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "content": ", we first perform forward passes with source prompt " + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "content": " and edited prompt " + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "content": ", respectively, to generate intermediate cross-attention maps. Then we average the cross-attention maps across all heads and layers with the spatial resolution " + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "inline_equation", + "content": "16 \\times 16" + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "content": ". The resulting cross-attention maps are denoted as " + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "inline_equation", + "content": "A_{t}^{c} \\in \\mathbb{R}^{16 \\times 16 \\times N}" + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "content": " is the number of the textual tokens. We then obtain the averaged cross-attention map for the token correlated to the foreground object. We denote " + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "inline_equation", + "content": "M_{s}" + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "content": " as masks extracted for the foreground objects in " + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "content": ", respectively. With these masks, we can restrict the object in " + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 582, + 288, + 715 + ], + "type": "text", + "content": " to query" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 72, + 525, + 84 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 525, + 84 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 525, + 84 + ], + "type": "text", + "content": "contents information only from the object region in " + }, + { + "bbox": [ + 305, + 72, + 525, + 84 + ], + "type": "inline_equation", + "content": "I_{s}" + }, + { + "bbox": [ + 305, + 72, + 525, + 84 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 348, + 87, + 545, + 102 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 348, + 87, + 545, + 102 + ], + "spans": [ + { + "bbox": [ + 348, + 87, + 545, + 102 + ], + "type": "interline_equation", + "content": "f _ {o} ^ {l} = \\text {A t t e n t i o n} \\left(Q ^ {l}, K _ {s} ^ {l}, V _ {s} ^ {l}; M _ {s}\\right), \\tag {3}", + "image_path": "4697087dd6739957a6eb24ee93aca7af0d7d730ea54aeb314e6942f426360098.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 350, + 105, + 545, + 118 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 350, + 105, + 545, + 118 + ], + "spans": [ + { + "bbox": [ + 350, + 105, + 545, + 118 + ], + "type": "interline_equation", + "content": "f _ {b} ^ {l} = \\text {A t t e n t i o n} \\left(Q ^ {l}, K _ {s} ^ {l}, V _ {s} ^ {l}; 1 - M _ {s}\\right), \\tag {4}", + "image_path": "ac45e45ecd2a870b510c5211839c8e848efe82709081330c6c4320a8da773456.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 350, + 121, + 545, + 135 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 350, + 121, + 545, + 135 + ], + "spans": [ + { + "bbox": [ + 350, + 121, + 545, + 135 + ], + "type": "interline_equation", + "content": "\\bar {f} ^ {l} = f _ {o} ^ {l} * M + f _ {b} ^ {l} * (1 - M), \\tag {5}", + "image_path": "a9c9b4b11ff542dbb8b8b1e662f80a0cb75b8d8ed6f1a0ba1e1cb6a59d29263b.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 140, + 545, + 200 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 140, + 545, + 200 + ], + "spans": [ + { + "bbox": [ + 304, + 140, + 545, + 200 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 140, + 545, + 200 + ], + "type": "inline_equation", + "content": "\\bar{f}^l" + }, + { + "bbox": [ + 304, + 140, + 545, + 200 + ], + "type": "text", + "content": " is the final attention output. The object and background regions in the target image query the contents from corresponding restricted areas rather than all source image features. Note that this strategy is optional and used when confusion occurs." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 206, + 538, + 219 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 206, + 538, + 219 + ], + "spans": [ + { + "bbox": [ + 305, + 206, + 538, + 219 + ], + "type": "text", + "content": "4.3. Integration to Controllable Diffusion Models" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 224, + 545, + 344 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 224, + 545, + 344 + ], + "spans": [ + { + "bbox": [ + 304, + 224, + 545, + 344 + ], + "type": "text", + "content": "Our method can be integrated into existing controllable diffusion models (e.g., T2I-Adapter [17] and ControlNet [45]) for more faithful non-rigid image synthesis and editing. These methods enable the original Stable Diffusion model to be more controllable (e.g., pose, sketch, segmentation map) in image synthesis. Thus we can use them to synthesize images with desired poses and shapes. Since our method can query image contents (e.g., textures) from a reference image, we can easily integrate our approach into these models to generate more consistent images." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 344, + 545, + 416 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 344, + 545, + 416 + ], + "spans": [ + { + "bbox": [ + 304, + 344, + 545, + 416 + ], + "type": "text", + "content": "Specifically, we follow the same process depicted in Alg. 1, and the desired target image synthesis process is changed from the original SD model to using these controllable models instead. In the following experiment section, we demonstrate the effectiveness of such a combination that can synthesize images consistently." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 422, + 388, + 436 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 422, + 388, + 436 + ], + "spans": [ + { + "bbox": [ + 306, + 422, + 388, + 436 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 442, + 545, + 609 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 442, + 545, + 609 + ], + "spans": [ + { + "bbox": [ + 304, + 442, + 545, + 609 + ], + "type": "text", + "content": "Setup. We apply the proposed method to the state-of-the-art text-to-image Stable Diffusion [27] model with publicly available checkpoints v1.4. We also validate the proposed method on the pre-trained anime-style model Anything-V4. Meanwhile, we perform editing on both synthetic images and real images. For real image editing, we first invert the image into the initial noise map with DDIM deterministic inversion [31]. Note that we set the starting noise map the same for source prompt " + }, + { + "bbox": [ + 304, + 442, + 545, + 609 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 304, + 442, + 545, + 609 + ], + "type": "text", + "content": " and the desired prompt " + }, + { + "bbox": [ + 304, + 442, + 545, + 609 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 304, + 442, + 545, + 609 + ], + "type": "text", + "content": " unless otherwise specified. During sampling, we perform DDIM sampling [31] with 50 denoising steps, and the classifier-free guidance is set to 7.5. The step and layer to start attention control is set to " + }, + { + "bbox": [ + 304, + 442, + 545, + 609 + ], + "type": "inline_equation", + "content": "S = 4" + }, + { + "bbox": [ + 304, + 442, + 545, + 609 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 442, + 545, + 609 + ], + "type": "inline_equation", + "content": "L = 10" + }, + { + "bbox": [ + 304, + 442, + 545, + 609 + ], + "type": "text", + "content": " as default. Note that it may be changed for specific checkpoints." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 613, + 491, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 613, + 491, + 624 + ], + "spans": [ + { + "bbox": [ + 306, + 613, + 491, + 624 + ], + "type": "text", + "content": "5.1. Comparisons with Previous Works" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 628, + 545, + 688 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 628, + 545, + 688 + ], + "spans": [ + { + "bbox": [ + 304, + 628, + 545, + 688 + ], + "type": "text", + "content": "We mainly compare the proposed tuning-free method to the current prompt-based editing methods with diffusion models, including tuning-free methods SDEdit [16], P2P [10], PnP [35], and Imagc [12]. We use their open-sourced codes to produce the editing results2." + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 306, + 693, + 545, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 693, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 306, + 693, + 545, + 712 + ], + "type": "text", + "content": "2We adopt the community version of Imagic as the official source code is not open-sourced" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 293, + 733, + 317, + 742 + ], + "type": "footer", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 733, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 733, + 317, + 742 + ], + "type": "text", + "content": "22565" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 68, + 545, + 373 + ], + "blocks": [ + { + "bbox": [ + 51, + 68, + 545, + 373 + ], + "lines": [ + { + "bbox": [ + 51, + 68, + 545, + 373 + ], + "spans": [ + { + "bbox": [ + 51, + 68, + 545, + 373 + ], + "type": "image", + "image_path": "7e8cd60ed70b342e7d572ae83f21cbbc09ff5b5b74c6af4eac910904178ab54e.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 381, + 548, + 444 + ], + "lines": [ + { + "bbox": [ + 46, + 381, + 548, + 444 + ], + "spans": [ + { + "bbox": [ + 46, + 381, + 548, + 444 + ], + "type": "text", + "content": "Figure 6: Editing results of different methods on the synthetic images (a) and real images (b). Our method enables consistent synthesis by combining the layout of the target prompt and the contents of source generated image. From left to right: the source generated source image with source prompt, synthesis results with the proposed MasaCtrl method, synthesis results from target prompt with the same random noise of source image, synthesis/editing results with existing methods P2P [10], SDEdit [16], PnP [35], and Imagc [12]." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 47, + 451, + 289, + 567 + ], + "blocks": [ + { + "bbox": [ + 47, + 451, + 289, + 567 + ], + "lines": [ + { + "bbox": [ + 47, + 451, + 289, + 567 + ], + "spans": [ + { + "bbox": [ + 47, + 451, + 289, + 567 + ], + "type": "image", + "image_path": "61d3aaf56ab96999494c435e35833206ec53446ba1c0dbb8353d4736c9f401c1.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 576, + 547, + 602 + ], + "lines": [ + { + "bbox": [ + 46, + 576, + 547, + 602 + ], + "spans": [ + { + "bbox": [ + 46, + 576, + 547, + 602 + ], + "type": "text", + "content": "Figure 7: Editing results of synthetic images (left part) and real images (right part) with MasaCtrl integrated into T2I-Adapter [17]." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 621, + 289, + 706 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 621, + 289, + 706 + ], + "spans": [ + { + "bbox": [ + 46, + 621, + 289, + 706 + ], + "type": "text", + "content": "Qualitative comparison. The consistent synthesis results are shown in Fig. 6(a). By directly modifying the text prompt, our method can synthesize content-consistent images. These synthesized images (1) contain contents (foreground objects and background) that are highly similar to those in the generated source images (first column of Fig. 6) and (2) highly comply with the target prompt " + }, + { + "bbox": [ + 46, + 621, + 289, + 706 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 46, + 621, + 289, + 706 + ], + "type": "text", + "content": " (third col" + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 304, + 451, + 545, + 567 + ], + "blocks": [ + { + "bbox": [ + 304, + 451, + 545, + 567 + ], + "lines": [ + { + "bbox": [ + 304, + 451, + 545, + 567 + ], + "spans": [ + { + "bbox": [ + 304, + 451, + 545, + 567 + ], + "type": "image", + "image_path": "b7b62ebe10786e9a150e928bc268d39462bd8090767b1988986e6d4805fcd794.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 621, + 547, + 706 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 621, + 547, + 706 + ], + "spans": [ + { + "bbox": [ + 304, + 621, + 547, + 706 + ], + "type": "text", + "content": "unn of Fig. 6). While existing methods fail to synthesize desired images, either conforming to the target text prompt or inconsistent with the source images. Our method also achieves promising results in editing real images shown in Fig. 6(b). The edited image is consistent with the target prompt and maintains source image content. These results demonstrate the effectiveness of the proposed method." + } + ] + } + ], + "index": 6 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 733, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 733, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 733, + 318, + 742 + ], + "type": "text", + "content": "22566" + } + ] + } + ], + "index": 7 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 71, + 547, + 167 + ], + "blocks": [ + { + "bbox": [ + 49, + 71, + 547, + 167 + ], + "lines": [ + { + "bbox": [ + 49, + 71, + 547, + 167 + ], + "spans": [ + { + "bbox": [ + 49, + 71, + 547, + 167 + ], + "type": "image", + "image_path": "44b04ab1a0e4304da209bc6bbc5a5e6656cf732ad8c556f0fe943d15c0c352f3.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 85, + 175, + 506, + 186 + ], + "lines": [ + { + "bbox": [ + 85, + 175, + 506, + 186 + ], + "spans": [ + { + "bbox": [ + 85, + 175, + 506, + 186 + ], + "type": "text", + "content": "Figure 8: Video synthesis results of proposed MasaCtrl with T2I-Adapter [17] (with key-pose guidance)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 208, + 287, + 376 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 208, + 287, + 376 + ], + "spans": [ + { + "bbox": [ + 46, + 208, + 287, + 376 + ], + "type": "text", + "content": "Quantitative comparison. For quantitative evaluation, we used 20 different source images (10 are synthetic and 10 are real) and edited them with P2P, PnP, Imagic, and MasaCtrl. We evaluate the text-alignment between the target prompt and edited image, and the image-alignment between the source and edited images in the CLIP feature space. Tab. 1 shows that MasaCtrl can synthesize images that comply with the target prompt while maintaining content consistency more than other methods. We also conducted a user study and collected 700 answers from professional participants. As shown in the preference column of Tab. 1, " + }, + { + "bbox": [ + 46, + 208, + 287, + 376 + ], + "type": "inline_equation", + "content": "73.5\\%" + }, + { + "bbox": [ + 46, + 208, + 287, + 376 + ], + "type": "text", + "content": " of participants preferred our method. Meanwhile, our method is efficient since no fine-tuning and optimization are required." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 376, + 287, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 376, + 287, + 544 + ], + "spans": [ + { + "bbox": [ + 46, + 376, + 287, + 544 + ], + "type": "text", + "content": "We further analyze the reasons attributed to the failure of existing methods (i.e., P2P, SDEdit, and PnP). These methods try to keep the original layout or object shape and pose unchanged by leveraging the layout information encoded in the cross-attention maps (P2P), features (PnP), and original input images (SDEdit). Meanwhile, the contents in the formed image mainly come from the encoded text embedding. As a result, the images synthesized by these methods have similar layouts to the source image but have different contents. In our proposed method MasaCtrl, the structure of the desired image is first determined by the former iteration in the denoising process, and the final image is formed by obtaining the image content from the source image. Thus we can perform various types of non-rigid image editing." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 549, + 189, + 562 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 549, + 189, + 562 + ], + "spans": [ + { + "bbox": [ + 47, + 549, + 189, + 562 + ], + "type": "text", + "content": "5.2. Results with T2I-Adapter" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 565, + 286, + 637 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 565, + 286, + 637 + ], + "spans": [ + { + "bbox": [ + 46, + 565, + 286, + 637 + ], + "type": "text", + "content": "The initial layout controlled by modifying the text prompt usually fails due to the inherent drawbacks of the Stable Diffusion model. Therefore, we further integrate our method into existing controllable synthesis pipelines to obtain stable synthesis and editing results. The synthetic and real image editing results of MasaCtrl with T2I-" + } + ] + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 50, + 641, + 285, + 689 + ], + "blocks": [ + { + "bbox": [ + 50, + 641, + 285, + 689 + ], + "lines": [ + { + "bbox": [ + 50, + 641, + 285, + 689 + ], + "spans": [ + { + "bbox": [ + 50, + 641, + 285, + 689 + ], + "type": "table", + "html": "
MethodText-alignmentImage-alignmentPreferenceRuntime
P2P [10]0.26910.87933.0%15s
PnP [35]0.25890.89022.5%60s
Imagic [12]0.26880.915921.0%14min
Ours0.27930.928673.5%16s
", + "image_path": "2ea4ba4cf19b8da617f804c0a2e009266143c0549c64be8c6e6dcedcc6d7a5ed.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "bbox": [ + 78, + 698, + 255, + 709 + ], + "lines": [ + { + "bbox": [ + 78, + 698, + 255, + 709 + ], + "spans": [ + { + "bbox": [ + 78, + 698, + 255, + 709 + ], + "type": "text", + "content": "Table 1: Quantitative and user study results." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 208, + 545, + 376 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 208, + 545, + 376 + ], + "spans": [ + { + "bbox": [ + 304, + 208, + 545, + 376 + ], + "type": "text", + "content": "Adapter [17] are shown in Fig. 7. We see that T2I-Adapter can generate an image with desired target layout, yet with different contents in the source image. In contrast, our method can effectively combine the layout synthesized by T2I-Adapter with the target prompt and the contents in the source image. Therefore, more faithful and fine-grained synthesis and editing results can be obtained. Note that we may change the attention strategy of starting denoising step " + }, + { + "bbox": [ + 304, + 208, + 545, + 376 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 304, + 208, + 545, + 376 + ], + "type": "text", + "content": " and U-Net layer " + }, + { + "bbox": [ + 304, + 208, + 545, + 376 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 304, + 208, + 545, + 376 + ], + "type": "text", + "content": " to obtain faithful results (" + }, + { + "bbox": [ + 304, + 208, + 545, + 376 + ], + "type": "inline_equation", + "content": "S = 2" + }, + { + "bbox": [ + 304, + 208, + 545, + 376 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 208, + 545, + 376 + ], + "type": "inline_equation", + "content": "L = 8" + }, + { + "bbox": [ + 304, + 208, + 545, + 376 + ], + "type": "text", + "content": " in our experiment), since the target layout is strongly controlled by extra guidance. Therefore, we can perform attention control in early steps and layers to query faithful contents in the source image, refer to the ablation study Sec. 5.5 for the analysis." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 382, + 460, + 394 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 382, + 460, + 394 + ], + "spans": [ + { + "bbox": [ + 306, + 382, + 460, + 394 + ], + "type": "text", + "content": "5.3. Robustness to Other Models" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 401, + 545, + 473 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 401, + 545, + 473 + ], + "spans": [ + { + "bbox": [ + 304, + 401, + 545, + 473 + ], + "type": "text", + "content": "Our method can be applied to other versions of Stable Diffusion models (e.g., v1.5), domain-specific models (e.g., the amine-style model Anything-v4), and customized models (e.g., models fine-tuned with DreamBooth [29]) to achieve consistent image synthesis and editing. Please refer to the supplementary materials for the visual results." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 479, + 463, + 492 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 479, + 463, + 492 + ], + "spans": [ + { + "bbox": [ + 306, + 479, + 463, + 492 + ], + "type": "text", + "content": "5.4. Extension to Video Synthesis" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 498, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 498, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 498, + 545, + 713 + ], + "type": "text", + "content": "Although our method is designed for consistent image synthesis and editing, we can easily extend our method for the video synthesis task using T2I-Adapter and ControlNet with a series of dense temporal-coherent guidance (e.g., pose, edge, depth). Specifically, we first generate a source image with the prompt " + }, + { + "bbox": [ + 304, + 498, + 545, + 713 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 304, + 498, + 545, + 713 + ], + "type": "text", + "content": " and guidance as the canonical frame (shown in the first column of Fig. 8). The other frames are synthesized separately with MasaCtrl. Then all the synthesized frames can be concatenated into a video since they are content-consistent with the source frame. Fig. 8 shows the video synthesis results with coherent dense guidance. The proposed method successfully synthesizes consistent frames with highly similar content (more video results are available on the project page and supplementary materials). However, our method can only animate the foreground objects (such as the bear in Fig. 8) and hardly bring the background alive. Therefore, video-based approaches still need to be explored since the current MasaCtrl has" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 733, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 733, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 733, + 317, + 742 + ], + "type": "text", + "content": "22567" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 70, + 220, + 159 + ], + "blocks": [ + { + "bbox": [ + 53, + 70, + 220, + 159 + ], + "lines": [ + { + "bbox": [ + 53, + 70, + 220, + 159 + ], + "spans": [ + { + "bbox": [ + 53, + 70, + 220, + 159 + ], + "type": "image", + "image_path": "039fd558c9fa8f06f3c107ba23d87462b8aab3e79b08806e755ec597eeb96827.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 226, + 70, + 543, + 160 + ], + "blocks": [ + { + "bbox": [ + 226, + 70, + 543, + 160 + ], + "lines": [ + { + "bbox": [ + 226, + 70, + 543, + 160 + ], + "spans": [ + { + "bbox": [ + 226, + 70, + 543, + 160 + ], + "type": "image", + "image_path": "3b95bc034362513c8e21e16b0e2fa7bb409bbca8b2ea333cb358f4527e43e5bc.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 50, + 176, + 545, + 266 + ], + "blocks": [ + { + "bbox": [ + 153, + 163, + 463, + 175 + ], + "lines": [ + { + "bbox": [ + 153, + 163, + 463, + 175 + ], + "spans": [ + { + "bbox": [ + 153, + 163, + 463, + 175 + ], + "type": "text", + "content": "(a) Results of mutual self-attention control starting from different denoising steps" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 50, + 176, + 545, + 266 + ], + "lines": [ + { + "bbox": [ + 50, + 176, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 50, + 176, + 545, + 266 + ], + "type": "image", + "image_path": "de95c48bb13b21a25fb6973b50b5f136dcdfb54526a0d1578d42e161257d54b0.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 168, + 269, + 426, + 281 + ], + "lines": [ + { + "bbox": [ + 168, + 269, + 426, + 281 + ], + "spans": [ + { + "bbox": [ + 168, + 269, + 426, + 281 + ], + "type": "text", + "content": "(b) Results of mutual self-attention control in different U-Net layers" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 289, + 546, + 337 + ], + "lines": [ + { + "bbox": [ + 46, + 289, + 546, + 337 + ], + "spans": [ + { + "bbox": [ + 46, + 289, + 546, + 337 + ], + "type": "text", + "content": "Figure 9: Results of mutual self-attention control in different denoising steps (a) and different U-Net layers (b). We see that only performing mutual self-attention control after several denoising steps (e.g., step 5), and in the decoder part (e.g., layer " + }, + { + "bbox": [ + 46, + 289, + 546, + 337 + ], + "type": "inline_equation", + "content": "10 \\sim 15" + }, + { + "bbox": [ + 46, + 289, + 546, + 337 + ], + "type": "text", + "content": ") can preserve the shape and structure information from target prompt " + }, + { + "bbox": [ + 46, + 289, + 546, + 337 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 46, + 289, + 546, + 337 + ], + "type": "text", + "content": " and query contents from the source image with prompt " + }, + { + "bbox": [ + 46, + 289, + 546, + 337 + ], + "type": "inline_equation", + "content": "P_{s}" + }, + { + "bbox": [ + 46, + 289, + 546, + 337 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 358, + 288, + 382 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 358, + 288, + 382 + ], + "spans": [ + { + "bbox": [ + 46, + 358, + 288, + 382 + ], + "type": "text", + "content": "a significant limitation in synthesizing scenes with background dynamics." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 393, + 141, + 406 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 393, + 141, + 406 + ], + "spans": [ + { + "bbox": [ + 47, + 393, + 141, + 406 + ], + "type": "text", + "content": "5.5. Ablation Study" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 415, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 415, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 415, + 289, + 715 + ], + "type": "text", + "content": "The results of both synthetic and real image editing can demonstrate the effectiveness of the proposed mutual self-attention control. We further analyze the control strategy in terms of different starting steps at the denoising process and the layers in the denoising U-Net. From Fig. 9(a), we see that performing mutual self-attention in the premature step can only synthesize an image identical to the source image, conveying all source image contents and ignoring the layout from the target prompt. As the step increases, the synthesized desired image can maintain the layout from the target prompt and the contents from the source image. While the image would gradually lose the source image contents and eventually becomes the image synthesized images without mutual self-attention control. We also observe a similar phenomenon when performing control in different U-Net layers shown in Fig. 9(b). Performing control among all layers can only generate an image identical to the source image. Performing control in low-resolution layers (i.e., layer " + }, + { + "bbox": [ + 46, + 415, + 289, + 715 + ], + "type": "inline_equation", + "content": "4 \\sim 10" + }, + { + "bbox": [ + 46, + 415, + 289, + 715 + ], + "type": "text", + "content": ") cannot preserve the source image contents and target layouts. While in high-resolution layers (i.e., layer " + }, + { + "bbox": [ + 46, + 415, + 289, + 715 + ], + "type": "inline_equation", + "content": "0 \\sim 3" + }, + { + "bbox": [ + 46, + 415, + 289, + 715 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 415, + 289, + 715 + ], + "type": "inline_equation", + "content": "10 \\sim 15" + }, + { + "bbox": [ + 46, + 415, + 289, + 715 + ], + "type": "text", + "content": "), the target layout can be maintained, and the source image contents can only be transformed when controlled in the decoder part. As a result, the proposed method performs control in the decoder part of U-Net after several denoising steps." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 357, + 460, + 369 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 357, + 460, + 369 + ], + "spans": [ + { + "bbox": [ + 306, + 357, + 460, + 369 + ], + "type": "text", + "content": "6. Limitations and Discussion" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 377, + 546, + 461 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 377, + 546, + 461 + ], + "spans": [ + { + "bbox": [ + 304, + 377, + 546, + 461 + ], + "type": "text", + "content": "Our method inherits most of the limitations of the Stable Diffusion model in generating desired images with text prompts. Please refer to the supplementary materials for detailed analysis and discussion. In addition, when editing real images, the DDIM inversion may fail to reconstruct the source images. In this case, MasaCtrl would fail to edit these images." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 472, + 379, + 483 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 472, + 379, + 483 + ], + "spans": [ + { + "bbox": [ + 306, + 472, + 379, + 483 + ], + "type": "text", + "content": "7. Conclusion" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 491, + 547, + 685 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 491, + 547, + 685 + ], + "spans": [ + { + "bbox": [ + 304, + 491, + 547, + 685 + ], + "type": "text", + "content": "We propose MasaCtrl, a tuning-free mutual self-attention control method applied to T2I diffusion models for non-rigid consistent image synthesis and editing. We convert the self-attention mechanism in diffusion models into a cross one, dubbed mutual self-attention, enabling effective structure and appearance query from the source image when applied to specific denoising steps and U-Net layers. We further consider the confusion problem of the foreground objects and background during the querying process and alleviate it with a mask-guided strategy. Meanwhile, our method can be easily integrated into recently proposed controllable strategies over diffusion models and perform consistent image synthesis and editing without fine-tuning the model and textural embedding. We believe such a method provides ordinary users with a convenient and effective way for content creation under text description." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 689, + 546, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 546, + 712 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 546, + 712 + ], + "type": "text", + "content": "Acknowledgement. This research was partly supported by JSPS KAKENHI Grant Numbers 22H00529, 20H05951." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 733, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 733, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 733, + 318, + 742 + ], + "type": "text", + "content": "22568" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 286, + 714 + ], + "type": "list", + "angle": 0, + "index": 18, + "blocks": [ + { + "bbox": [ + 53, + 91, + 286, + 112 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 286, + 112 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 286, + 112 + ], + "type": "text", + "content": "[1] Omri Avrahami, Ohad Fried, and Dani Lischinski. Blended latent diffusion. arXiv preprint arXiv:2206.02779, 2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 114, + 286, + 146 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 114, + 286, + 146 + ], + "spans": [ + { + "bbox": [ + 53, + 114, + 286, + 146 + ], + "type": "text", + "content": "[2] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. arXiv preprint arXiv:1809.11096, 2018." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 148, + 286, + 190 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 148, + 286, + 190 + ], + "spans": [ + { + "bbox": [ + 53, + 148, + 286, + 190 + ], + "type": "text", + "content": "[3] Hila Chefer, Yuval Alaluf, Yael Vinker, Lior Wolf, and Daniel Cohen-Or. Attend-and-excite: Attention-based semantic guidance for text-to-image diffusion models. arXiv preprint arXiv:2301.13826, 2023." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 192, + 286, + 246 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 192, + 286, + 246 + ], + "spans": [ + { + "bbox": [ + 53, + 192, + 286, + 246 + ], + "type": "text", + "content": "[4] Katherine Crowson, Stella Biderman, Daniel Kornis, Dashiell Stander, Eric Hallahan, Louis Castricato, and Edward Raff. Vqgan-clip: Open domain image generation and editing with natural language guidance. In ECCV, pages 88–105. Springer, 2022." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 247, + 286, + 278 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 247, + 286, + 278 + ], + "spans": [ + { + "bbox": [ + 53, + 247, + 286, + 278 + ], + "type": "text", + "content": "[5] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. NeurIPS, 34:8780-8794, 2021." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 280, + 286, + 323 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 280, + 286, + 323 + ], + "spans": [ + { + "bbox": [ + 53, + 280, + 286, + 323 + ], + "type": "text", + "content": "[6] Ming Ding, Zhuoyi Yang, Wenyi Hong, Wendi Zheng, Chang Zhou, Da Yin, Junyang Lin, Xu Zou, Zhou Shao, Hongxia Yang, et al. Cogview: Mastering text-to-image generation via transformers. NeurIPS, 34:19822-19835, 2021." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 324, + 286, + 356 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 324, + 286, + 356 + ], + "spans": [ + { + "bbox": [ + 53, + 324, + 286, + 356 + ], + "type": "text", + "content": "[7] Patrick Esser, Robin Rombach, and Bjorn Ommer. Taming transformers for high-resolution image synthesis. In CVPR, pages 12873-12883, 2021." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 357, + 286, + 402 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 357, + 286, + 402 + ], + "spans": [ + { + "bbox": [ + 53, + 357, + 286, + 402 + ], + "type": "text", + "content": "[8] Shuyang Gu, Dong Chen, Jianmin Bao, Fang Wen, Bo Zhang, Dongdong Chen, Lu Yuan, and Baining Guo. Vector quantized diffusion model for text-to-image synthesis. In CVPR, pages 10696-10706, 2022." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 403, + 286, + 434 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 403, + 286, + 434 + ], + "spans": [ + { + "bbox": [ + 53, + 403, + 286, + 434 + ], + "type": "text", + "content": "[9] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778, 2016." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 436, + 286, + 479 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 436, + 286, + 479 + ], + "spans": [ + { + "bbox": [ + 48, + 436, + 286, + 479 + ], + "type": "text", + "content": "[10] Amir Hertz, Ron Mokady, Jay Tenenbaum, Kfir Aberman, Yael Pritch, and Daniel Cohen-Or. Prompt-to-prompt image editing with cross attention control. arXiv preprint arXiv:2208.01626, 2022." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 480, + 286, + 502 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 480, + 286, + 502 + ], + "spans": [ + { + "bbox": [ + 48, + 480, + 286, + 502 + ], + "type": "text", + "content": "[11] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. NeurIPS, 33:6840-6851, 2020." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 502, + 286, + 545 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 502, + 286, + 545 + ], + "spans": [ + { + "bbox": [ + 48, + 502, + 286, + 545 + ], + "type": "text", + "content": "[12] Bahjat Kawar, Shiran Zada, Oran Lang, Omer Tov, Huiwen Chang, Tali Dekel, Inbar Mosseri, and Michal Irani. Imagc: Text-based real image editing with diffusion models. arXiv preprint arXiv:2210.09276, 2022." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 547, + 286, + 579 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 547, + 286, + 579 + ], + "spans": [ + { + "bbox": [ + 48, + 547, + 286, + 579 + ], + "type": "text", + "content": "[13] Gwanghyun Kim, Taesung Kwon, and Jong Chul Ye. Diffusionclip: Text-guided diffusion models for robust image manipulation. In CVPR, pages 2426-2435, 2022." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 580, + 286, + 612 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 580, + 286, + 612 + ], + "spans": [ + { + "bbox": [ + 48, + 580, + 286, + 612 + ], + "type": "text", + "content": "[14] Bowen Li, Xiaojuan Qi, Thomas Lukasiewicz, and Philip Torr. Controllable text-to-image generation. NeurIPS, 32, 2019." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 614, + 286, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 614, + 286, + 646 + ], + "spans": [ + { + "bbox": [ + 48, + 614, + 286, + 646 + ], + "type": "text", + "content": "[15] Bowen Li, Xiaojuan Qi, Thomas Lukasiewicz, and Philip HS Torr. Manigan: Text-guided image manipulation. In CVPR, pages 7880-7889, 2020." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 647, + 286, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 286, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 286, + 689 + ], + "type": "text", + "content": "[16] Chenlin Meng, Yang Song, Jiaming Song, Jiajun Wu, JunYan Zhu, and Stefano Ermon. Sdedit: Image synthesis and editing with stochastic differential equations. arXiv preprint arXiv:2108.01073, 2021." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 48, + 691, + 286, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 286, + 714 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 286, + 714 + ], + "type": "text", + "content": "[17] Chong Mou, Xintao Wang, Liangbin Xie, Jian Zhang, Zhonggang Qi, Ying Shan, and Xiaohu Qie. T2i-adapter: Learning" + } + ] + } + ], + "index": 17 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 714 + ], + "type": "list", + "angle": 0, + "index": 35, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "text", + "content": "adapters to dig out more controllable ability for text-to-image diffusion models. arXiv preprint arXiv:2302.08453, 2023." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 95, + 545, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 95, + 545, + 128 + ], + "spans": [ + { + "bbox": [ + 308, + 95, + 545, + 128 + ], + "type": "text", + "content": "[18] Seonghyeon Nam, Yunji Kim, and Seon Joo Kim. Text-adaptive generative adversarial networks: manipulating images with natural language. NeurIPS, 31, 2018." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 129, + 545, + 182 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 129, + 545, + 182 + ], + "spans": [ + { + "bbox": [ + 308, + 129, + 545, + 182 + ], + "type": "text", + "content": "[19] Alex Nichol, Prafulla Dhariwal, Aditya Ramesh, Pranav Shyam, Pamela Mishkin, Bob McGrew, Ilya Sutskever, and Mark Chen. Glide: Towards photorealistic image generation and editing with text-guided diffusion models. arXiv preprint arXiv:2112.10741, 2021." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 183, + 545, + 215 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 183, + 545, + 215 + ], + "spans": [ + { + "bbox": [ + 308, + 183, + 545, + 215 + ], + "type": "text", + "content": "[20] Alexander Quinn Nichol and Prafulla Dhariwal. Improved denoising diffusion probabilistic models. In ICML, pages 8162-8171. PMLR, 2021." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 217, + 545, + 249 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 217, + 545, + 249 + ], + "spans": [ + { + "bbox": [ + 308, + 217, + 545, + 249 + ], + "type": "text", + "content": "[21] Gaurav Parmar, Krishna Kumar Singh, Richard Zhang, Yijun Li, Jingwan Lu, and Jun-Yan Zhu. Zero-shot image-to-image translation. arXiv preprint arXiv:2302.03027, 2023." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 250, + 545, + 282 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 250, + 545, + 282 + ], + "spans": [ + { + "bbox": [ + 308, + 250, + 545, + 282 + ], + "type": "text", + "content": "[22] Or Patashnik, Zongze Wu, Eli Shechtman, Daniel Cohen-Or, and Dani Lischinski. Styleclip: Text-driven manipulation of stylegan imagery. In ICCV, pages 2085–2094, 2021." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 284, + 545, + 338 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 284, + 545, + 338 + ], + "spans": [ + { + "bbox": [ + 308, + 284, + 545, + 338 + ], + "type": "text", + "content": "[23] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In ICML, pages 8748-8763. PMLR, 2021." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 338, + 545, + 380 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 338, + 545, + 380 + ], + "spans": [ + { + "bbox": [ + 308, + 338, + 545, + 380 + ], + "type": "text", + "content": "[24] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. arXiv preprint arXiv:2204.06125, 2022." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 383, + 545, + 425 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 383, + 545, + 425 + ], + "spans": [ + { + "bbox": [ + 308, + 383, + 545, + 425 + ], + "type": "text", + "content": "[25] Aditya Ramesh, Mikhail Pavlov, Gabriel Goh, Scott Gray, Chelsea Voss, Alec Radford, Mark Chen, and Ilya Sutskever. Zero-shot text-to-image generation. In ICML, pages 8821-8831. PMLR, 2021." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 426, + 545, + 469 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 426, + 545, + 469 + ], + "spans": [ + { + "bbox": [ + 308, + 426, + 545, + 469 + ], + "type": "text", + "content": "[26] Scott Reed, Zeynep Akata, Xinchen Yan, Lajanugen Logeswaran, Bernt Schiele, and Honglak Lee. Generative adversarial text to image synthesis. In ICML, pages 1060-1069. PMLR, 2016." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 471, + 545, + 514 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 471, + 545, + 514 + ], + "spans": [ + { + "bbox": [ + 308, + 471, + 545, + 514 + ], + "type": "text", + "content": "[27] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In CVPR, pages 10684-10695, 2022." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 308, + 515, + 545, + 548 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 515, + 545, + 548 + ], + "spans": [ + { + "bbox": [ + 308, + 515, + 545, + 548 + ], + "type": "text", + "content": "[28] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In MICCAI, pages 234-241. Springer, 2015." + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 308, + 548, + 545, + 592 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 548, + 545, + 592 + ], + "spans": [ + { + "bbox": [ + 308, + 548, + 545, + 592 + ], + "type": "text", + "content": "[29] Nataniel Ruiz, Yuanzhen Li, Varun Jampani, Yael Pritch, Michael Rubinstein, and Kfir Aberman. Dreambooth: Fine tuning text-to-image diffusion models for subject-driven generation. arXiv preprint arXiv:2208.12242, 2022." + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 308, + 593, + 545, + 657 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 593, + 545, + 657 + ], + "spans": [ + { + "bbox": [ + 308, + 593, + 545, + 657 + ], + "type": "text", + "content": "[30] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Burcu Karagol Ayan, S Sara Mahdavi, Rapha Gontijo Lopes, et al. Photorealistic text-to-image diffusion models with deep language understanding. arXiv preprint arXiv:2205.11487, 2022." + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 308, + 658, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 658, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 658, + 545, + 689 + ], + "type": "text", + "content": "[31] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. arXiv preprint arXiv:2010.02502, 2020." + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 308, + 691, + 545, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 691, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 308, + 691, + 545, + 714 + ], + "type": "text", + "content": "[32] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. NeurIPS, 32, 2019." + } + ] + } + ], + "index": 34 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 733, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 733, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 733, + 318, + 742 + ], + "type": "text", + "content": "22569" + } + ] + } + ], + "index": 36 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 678 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[33] Raphael Tang, Akshit Pandey, Zhiying Jiang, Gefei Yang, Karun Kumar, Jimmy Lin, and Ferhan Ture. What the daam: Interpreting stable diffusion using cross attention. arXiv preprint arXiv:2210.04885, 2022." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 118, + 287, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 118, + 287, + 161 + ], + "spans": [ + { + "bbox": [ + 49, + 118, + 287, + 161 + ], + "type": "text", + "content": "[34] Ming Tao, Hao Tang, Fei Wu, Xiao-Yuan Jing, Bing-Kun Bao, and Changsheng Xu. Df-gan: A simple and effective baseline for text-to-image synthesis. In CVPR, pages 16515-16525, 2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 163, + 288, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 163, + 288, + 205 + ], + "spans": [ + { + "bbox": [ + 48, + 163, + 288, + 205 + ], + "type": "text", + "content": "[35] Narek Tumanyan, Michal Geyer, Shai Bagon, and Tali Dekel. Plug-and-play diffusion features for text-driven image-to-image translation. arXiv preprint arXiv:2211.12572, 2022." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 208, + 288, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 208, + 288, + 239 + ], + "spans": [ + { + "bbox": [ + 48, + 208, + 288, + 239 + ], + "type": "text", + "content": "[36] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. NeurIPS, 30, 2017." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 241, + 288, + 296 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 241, + 288, + 296 + ], + "spans": [ + { + "bbox": [ + 48, + 241, + 288, + 296 + ], + "type": "text", + "content": "[37] Jay Zhangjie Wu, Yixiao Ge, Xintao Wang, Weixian Lei, Yuchao Gu, Wynne Hsu, Ying Shan, Xiaohu Qie, and Mike Zheng Shou. Tune-a-video: One-shot tuning of image diffusion models for text-to-video generation. arXiv preprint arXiv:2212.11565, 2022." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 297, + 287, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 297, + 287, + 330 + ], + "spans": [ + { + "bbox": [ + 48, + 297, + 287, + 330 + ], + "type": "text", + "content": "[38] Weihao Xia, Yujiu Yang, Jing-Hao Xue, and Baoyuan Wu. Tedigan: Text-guided diverse face image generation and manipulation. In CVPR, pages 2256-2265, 2021." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 331, + 287, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 331, + 287, + 374 + ], + "spans": [ + { + "bbox": [ + 48, + 331, + 287, + 374 + ], + "type": "text", + "content": "[39] Tao Xu, Pengchuan Zhang, Qiuyuan Huang, Han Zhang, Zhe Gan, Xiaolei Huang, and Xiaodong He. Attngan: Fine-grained text to image generation with attentional generative adversarial networks. In CVPR, pages 1316-1324, 2018." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 376, + 287, + 418 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 376, + 287, + 418 + ], + "spans": [ + { + "bbox": [ + 48, + 376, + 287, + 418 + ], + "type": "text", + "content": "[40] Hui Ye, Xiulong Yang, Martin Takac, Rajshekhar Sunderraman, and Shihao Ji. Improving text-to-image synthesis using contrastive learning. arXiv preprint arXiv:2107.02423, 2021." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 421, + 287, + 475 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 421, + 287, + 475 + ], + "spans": [ + { + "bbox": [ + 48, + 421, + 287, + 475 + ], + "type": "text", + "content": "[41] Jiahui Yu, Yuanzhong Xu, Jing Yu Koh, Thang Luong, Gunjan Baid, Zirui Wang, Vijay Vasudevan, Alexander Ku, Yinfei Yang, Burcu Karagol Ayan, et al. Scaling autoregressive models for content-rich text-to-image generation. arXiv preprint arXiv:2206.10789, 2022." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 476, + 287, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 476, + 287, + 510 + ], + "spans": [ + { + "bbox": [ + 48, + 476, + 287, + 510 + ], + "type": "text", + "content": "[42] Han Zhang, Jing Yu Koh, Jason Baldridge, Honglak Lee, and Yinfei Yang. Cross-modal contrastive learning for text-to-image generation. In CVPR, pages 833-842, 2021." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 510, + 287, + 564 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 510, + 287, + 564 + ], + "spans": [ + { + "bbox": [ + 48, + 510, + 287, + 564 + ], + "type": "text", + "content": "[43] Han Zhang, Tao Xu, Hongsheng Li, Shaoting Zhang, Xiaogang Wang, Xiaolei Huang, and Dimitris N Metaxas. Stackgan: Text to photo-realistic image synthesis with stacked generative adversarial networks. In ICCV, pages 5907-5915, 2017." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 566, + 287, + 609 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 566, + 287, + 609 + ], + "spans": [ + { + "bbox": [ + 48, + 566, + 287, + 609 + ], + "type": "text", + "content": "[44] Han Zhang, Tao Xu, Hongsheng Li, Shaoting Zhang, Xiaogang Wang, Xiaolei Huang, and Dimitris N Metaxas. Stackgan++: Realistic image synthesis with stacked generative adversarial networks. IEEE TPAMI, 41(8):1947-1962, 2018." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 611, + 287, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 611, + 287, + 643 + ], + "spans": [ + { + "bbox": [ + 48, + 611, + 287, + 643 + ], + "type": "text", + "content": "[45] Lvmin Zhang and Maneesh Agrawala. Adding conditional control to text-to-image diffusion models. arXiv preprint arXiv:2302.05543, 2023." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 644, + 287, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 644, + 287, + 678 + ], + "spans": [ + { + "bbox": [ + 48, + 644, + 287, + 678 + ], + "type": "text", + "content": "[46] Minfeng Zhu, Pingbo Pan, Wei Chen, and Yi Yang. Dm-gan: Dynamic memory generative adversarial networks for text-to-image synthesis. In CVPR, pages 5802-5810, 2019." + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 734, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 734, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 734, + 318, + 742 + ], + "type": "text", + "content": "22570" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/2a13e96b-8070-4a45-a596-f26ce5eefa9a_content_list.json b/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/2a13e96b-8070-4a45-a596-f26ce5eefa9a_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..72c3c67b45b0adc2dc14981c4c77345a4cc4aaef --- /dev/null +++ b/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/2a13e96b-8070-4a45-a596-f26ce5eefa9a_content_list.json @@ -0,0 +1,1683 @@ +[ + { + "type": "text", + "text": "Mask-Attention-Free Transformer for 3D Instance Segmentation", + "text_level": 1, + "bbox": [ + 156, + 130, + 813, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Xin Lai1 Yuhui Yuan3 Ruihang Chu1 \n1The Chinese University of Hong Kong", + "bbox": [ + 91, + 178, + 468, + 219 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Yukang Chen $^{1}$ Han Hu $^{3}$ Jiaya Jia $^{1,2*}$ $^{2}$ SmartMore ${ }^{3}$ Microsoft Research Asia", + "bbox": [ + 480, + 178, + 883, + 215 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 251, + 313, + 267 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Recently, transformer-based methods have dominated 3D instance segmentation, where mask attention is commonly involved. Specifically, object queries are guided by the initial instance masks in the first cross-attention, and then iteratively refine themselves in a similar manner. However, we observe that the mask-attention pipeline usually leads to slow convergence due to low-recall initial instance masks. Therefore, we abandon the mask attention design and resort to an auxiliary center regression task instead. Through center regression, we effectively overcome the low-recall issue and perform cross-attention by imposing positional prior. To reach this goal, we develop a series of position-aware designs. First, we learn a spatial distribution of 3D locations as the initial position queries. They spread over the 3D space densely, and thus can easily capture the objects in a scene with a high recall. Moreover, we present relative position encoding for the cross-attention and iterative refinement for more accurate position queries. Experiments show that our approach converges $4\\times$ faster than existing work, sets a new state of the art on ScanNetv2 3D instance segmentation benchmark, and also demonstrates superior performance across various datasets. Code and models are available at https://github.com/dvlab-research/Mask-Attention-Free-Transformer.", + "bbox": [ + 76, + 282, + 473, + 660 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 686, + 209, + 703 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Nowadays 3D point clouds can be conveniently collected. They have benefited various applications, such as autonomous driving, robotics, and augmented reality. As a fundamental task, 3D instance segmentation also poses great challenges simultaneously, such as geometric occlusion and semantic ambiguity.", + "bbox": [ + 75, + 712, + 468, + 804 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Many works have been proposed to solve the 3D instance segmentation task. Grouping-based methods [25, 55, 5, 75] rely on heuristic clustering algorithms such as DBSCAN or Breadth-First Search (BFS) to generate instance proposals. They thus require sophisticated hyper-parameters", + "bbox": [ + 75, + 804, + 470, + 878 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/618eb093ee1d77ccda03fa2bf3a161b9c7c9d4c63897dad16e183746fe163f50.jpg", + "image_caption": [ + "Figure 1. Validation curve of the baseline and ours on ScanNetv2 val set. With only 128-epoch training, ours outperforms the baseline trained with 512 epochs." + ], + "image_footnote": [], + "bbox": [ + 516, + 253, + 875, + 478 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "tuning and are prone to wrongly segment instances that are close to each other. Recently, transformer-based methods [49, 50] develop a fully end-to-end pipeline. With transformer decoder layers, a fixed number of object queries attend to global features iteratively and directly output instance predictions. It requires no post-processing for duplicate removal such as NMS, since it adopts one-to-one bipartite matching during training. Moreover, it employs mask attention, which uses the instance masks predicted in the last layer to guide the cross-attention.", + "bbox": [ + 496, + 537, + 893, + 688 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "However, we point out that current transformer-based methods suffer from the issue of slow convergence. As shown in Fig. 1, the baseline model manifests slow convergence and lags behind our method by a large margin, particularly in the early stages of training. We dive further and find that the issue is potentially caused by the low recall of the initial instance masks. Specifically, as shown in Fig. 2 (a), the initial instance masks are produced by the similarity map between the initial object queries and the point-wise mask features. Since the initial object queries are unstable in early training, we notice that the recall of initial instance masks is substantially lower than ours in Fig. 3, especially at the beginning of training (i.e., the 32-th epoch). The low-quality initial instance masks increase the training difficulty,", + "bbox": [ + 496, + 689, + 895, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding Author", + "bbox": [ + 94, + 887, + 223, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "3693", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/c9d7f9030400789b78ebc3e1dbbfec373b103d4f6c0e18d7c34918cedd709a11.jpg", + "image_caption": [ + "Figure 2. The framework of (a) existing works (based on mask attention) and (b) ours. Existing works have the issue of low-recall initial instance masks (i.e., $\\mathcal{M}_0$ ). Our approach resorts to an auxiliary center regression task to circumvent this issue." + ], + "image_footnote": [], + "bbox": [ + 81, + 89, + 467, + 198 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "thereby slowing down convergence.", + "bbox": [ + 76, + 276, + 315, + 290 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Given the low recall of the initial instance masks, we abandon the mask attention design and instead construct an auxiliary center regression task to guide cross-attention, as depicted in Fig. 2 (b). To enable center regression, we develop a series of position-aware designs. Firstly, we maintain a set of learnable position queries, each of which denotes the position of its corresponding content query. They are densely distributed over the 3D space, and we require each query to attend to its local region. As a result, the queries can easily capture the objects in a scene with a higher recall, which is crucial in reducing training difficulty and accelerating convergence.", + "bbox": [ + 75, + 291, + 468, + 472 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In addition, we design the contextual relative position encoding for cross-attention. Compared to the mask attention used in previous works, our solution is more flexible since the attention weights are adjusted by relative positions instead of hard masking. Furthermore, we iteratively update the position queries to achieve more accurate representation. Finally, we introduce the center distances between predictions and ground truths in both matching and loss.", + "bbox": [ + 75, + 472, + 468, + 592 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In total, our contribution is three-fold.", + "bbox": [ + 96, + 593, + 348, + 606 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We observe that existing transformer-based methods suffer from the low recall of initial instance masks, which causes training difficulty and slow convergence.", + "Instead of relying on mask attention, we construct an auxiliary center regression task to overcome the lowrecall issue and design a series of position-aware components accordingly. Our approach manifests faster convergence and demonstrates higher performance.", + "- Experiments show our approach achieves a new state-of-the-art result and demonstrates superior performance on various datasets including ScanNetv2, ScanNet200, and S3DIS." + ], + "bbox": [ + 94, + 614, + 468, + 811 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 76, + 821, + 218, + 835 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. 3D Instance Segmentation", + "text_level": 1, + "bbox": [ + 76, + 847, + 313, + 863 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "3D instance segmentation is a fundamental task for 3D recognition [45, 46, 28, 6, 32, 36, 31, 35, 27, 24, 34,", + "bbox": [ + 75, + 869, + 468, + 900 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/6d85ce4170994191cbf1e92e2cfbba931d0eab4ba3606b44d74fc623dd1442a4.jpg", + "image_caption": [ + "Figure 3. The recall of initial instance masks at the 32-th and 80-th training epoch. We compare the baseline trained with 512 epochs and ours trained with 128, 256, and 512 epochs. Since our approach does not produce initial instance masks before entering decoder layers, we make statistics on the instance masks output by the first decoder layer for both the baseline and ours." + ], + "image_footnote": [], + "bbox": [ + 526, + 97, + 870, + 300 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "11]. The solutions can be categorized into detection-based, grouping-based and the new emerging transformer-based paradigms. Detection-based approaches [21, 2, 67] first detect the bounding boxes and then segment the fine-grained instance mask. On the other hand, grouping-based approaches [60, 61, 26, 17, 19, 25, 23, 20, 69, 33, 5, 55, 12, 10] employ clustering algorithms to group the points into a set of instance clusters. Before clustering, they either move 3D points towards the associated object center to form a more compact distribution [26, 19, 25, 23, 69, 33, 5, 55], or transform points to a high-dimension feature space [60, 61]. Further, a series of works leverage semantic priors to avoid the noisy points from other categories [26, 25, 33, 5, 55] or use advanced grouping strategies [55, 5, 33]. With these designs, the grouping-based paradigm has achieved leading performance across various evaluation benchmarks[1, 14] for a long time. Recently, transformer-based paradigm [49, 50] becomes another option and swiftly sets a new state-of-the-art. Compared with previous methods, it presents an elegant pipeline, and can directly output instance predictions. It relies on the transformer decoder and mask attention to aggregate information from global features. In this work, we construct an auxiliary center regression task to assist in cross-attention. Although the existing grouping-based methods also predict center offsets, we explain that ours is not for instance proposals, but to overcome the lowrecall issue and provide positional priors for cross-attention.", + "bbox": [ + 496, + 407, + 890, + 816 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. Vision Transformer", + "text_level": 1, + "bbox": [ + 500, + 830, + 687, + 844 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Transformer has become a fundamental model in the vision area, thanks to its flexibility and power to model various scenarios using attention mechanisms [54]. Re", + "bbox": [ + 496, + 854, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "3694", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/fdb0fc6b3c5aa90f360f3ed8e90077714876203d9e3fca7d9f763c6e218ee714.jpg", + "image_caption": [ + "Figure 4. The overview of our framework. Besides content queries $\\mathcal{Q}_0^c$ , we also maintain a set of learnable position queries $\\mathcal{Q}_0^p$ . The content queries $\\mathcal{Q}^c$ aggregate features from the global features $\\mathcal{F}$ . The position queries $\\mathcal{Q}^p$ are designed to guide the cross-attention. The attention weights are adjusted based on the relative positions between the position queries $\\mathcal{Q}^p$ and the global positions $\\mathcal{P}$ . Both content and position queries are iteratively refined in each layer. Only 3 decoder layers are shown (we use 6 layers in our experiments)." + ], + "image_footnote": [], + "bbox": [ + 80, + 89, + 888, + 368 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "cently, many works [16, 52, 53, 59, 58, 13, 15, 51, 66] rely on the self-attention in transformers to develop vision fundamental models. Besides, DETR [3] proposes a fully end-to-end pipeline for object detection. It utilizes transformer decoders to dynamically aggregate features from images, and uses one-to-one bipartite matching for ground-truth assignment, yielding an elegant pipeline. To solve the notorious slow convergence of DETR, approaches [76, 62, 41, 37, 70, 68] propose deformable attention, impose strong prior or decrease searching space in cross-attention to accelerate convergence. Further, methods of [29, 39, 22, 71, 30] present several ways to stabilize matching and training. Moreover, masked attention [8, 7] are proposed to impose semantic priors to accelerate training for segmentation tasks. Recently, there are works [28, 73, 63, 64, 43, 49, 50] that develop transformer models tailored for 3D point clouds. Following this line of research, we observe the low recall of initial instance masks, and present solutions to circumvent the use of mask attention.", + "bbox": [ + 75, + 446, + 472, + 750 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Method", + "text_level": 1, + "bbox": [ + 76, + 763, + 166, + 779 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We first review previous methods and present the overview of our method in Sec. 3.1. Then, we elaborate on the details of our position-aware designs in Sec. 3.2.", + "bbox": [ + 75, + 790, + 468, + 835 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Overview", + "text_level": 1, + "bbox": [ + 76, + 845, + 187, + 859 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Preliminary. Recently, Mask3D [49] and SPFormer [50] present a fully end-to-end pipeline, which allows the object", + "bbox": [ + 75, + 869, + 468, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "queries to directly output instance predictions. With transformer decoders, a fixed number of object queries aggregate information from the global features (either multi-scale voxel features [49] or superpoint features [50]) extracted with the backbone. Moreover, similar to Mask2Former [8, 7], they adopt mask attention and rely on the instance masks to guide the cross-attention. Specifically, the cross-attention is masked with the instance masks predicted in the last decoder layer, so that the queries only need to consider the masked features. However, as shown in Fig. 3, the recall of initial instance masks is low in the early stages of training. It hinders the ability to achieve a high-quality result in the subsequent layers and thus increases training difficulty.", + "bbox": [ + 496, + 446, + 893, + 645 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Ours. Instead of relying on mask attention, we propose an auxiliary center regression task to guide instance segmentation. The overview of our method is shown in Fig. 4 (a). We first yield the global positions $\\mathcal{P} \\in \\mathbb{R}^{N \\times 3}$ from the input point cloud and extract the global features $\\mathcal{F} \\in \\mathbb{R}^{N \\times d}$ using the backbone ( $\\mathcal{P}$ and $\\mathcal{F}$ can be either voxels [49] or superpoints [50] positions and features). In contrast to existing works, besides the content queries $\\mathcal{Q}_0^c \\in \\mathbb{R}^{n \\times d}$ , we also maintain a fixed number of position queries $\\mathcal{Q}_0^p \\in [0,1]^{n \\times 3}$ that represent the normalized instance centers. $\\mathcal{Q}_0^p$ is randomly initialized and $\\mathcal{Q}_0^c$ is initialized with zero. Given the global positions $\\mathcal{P}$ and global features $\\mathcal{F}$ , our goal is to let the positional queries guide their corresponding content queries in cross-attention, and then iteratively refine both sets of queries, and finally predict the instance centers, classes and masks. For the $t$ -th decoder layer, this process", + "bbox": [ + 496, + 657, + 893, + 902 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "3695", + "bbox": [ + 482, + 944, + 514, + 957 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/17ffc6992a3a51b10149207fa5653ca8cf33c708a4f6e2d6e69aa6ace5bc1633.jpg", + "image_caption": [ + "Figure 5. The illustration for relative position encoding. We note the shape of the corresponding tensor at the bottom." + ], + "image_footnote": [], + "bbox": [ + 81, + 88, + 467, + 200 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "is formulated as", + "bbox": [ + 76, + 260, + 187, + 273 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {C e n t e r} _ {t} = \\mathbf {M L P} _ {\\text {c e n t e r}} \\left(\\mathbf {Q} _ {t} ^ {c}\\right) + \\mathbf {Q} _ {t - 1} ^ {p}, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 140, + 287, + 468, + 306 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {C l a s s} _ {t} = \\mathbf {M L P} _ {c l s} \\left(\\mathbf {Q} _ {t} ^ {c}\\right), \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 187, + 332, + 468, + 349 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {M a s k} _ {t} = \\sigma \\left(\\mathbf {Q} _ {t} ^ {c} \\cdot \\mathcal {F} _ {\\text {m a s k}} ^ {T}\\right) < 0. 5, \\mathcal {F} _ {\\text {m a s k}} = \\mathbf {M L P} _ {\\text {m a s k}} (\\mathcal {F}), \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 76, + 382, + 480, + 412 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbf{Center}_t\\in \\mathbb{R}^{n\\times 3}$ , $\\mathbf{Class}_t\\in \\mathbb{R}^{n\\times K}$ and $\\mathbf{Mask}_t\\in \\{0,1\\}^{n\\times N}$ are the predicted centers, classification logits, and the instance masks.", + "bbox": [ + 76, + 414, + 468, + 459 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Position-aware Designs", + "text_level": 1, + "bbox": [ + 76, + 469, + 290, + 486 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To effectively support the center regression task and improve the recall of initial instance masks, we propose a series of position-aware designs as follows.", + "bbox": [ + 76, + 493, + 468, + 539 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Learnable Position Query. Unlike previous works [49, 50], we introduce an additional set of position queries $\\mathcal{Q}_0^p\\in [0,1]^{n\\times 3}$ . Since the range of points varies significantly among different scenes, the initial position queries are stored in a normalized form as learnable parameters followed by sigmoid function. Basically, we can obtain the absolute positions $\\hat{\\mathcal{Q}}_t^p\\in \\mathbb{R}^{n\\times 3}$ from the normalized position queries $\\mathcal{Q}_t^p$ for a given input scene as", + "bbox": [ + 76, + 558, + 468, + 679 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {\\mathcal {Q}} _ {t} ^ {p} = \\mathcal {Q} _ {t} ^ {p} \\cdot \\left(p _ {\\max } - p _ {\\min }\\right) + p _ {\\min }, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 153, + 694, + 468, + 712 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where the $p_{min}, p_{max} \\in \\mathbb{R}^3$ represent the minimum and maximum coordinates of the input scene, respectively. The resultant $\\hat{\\mathcal{Q}}_t^p$ explicitly represents the positions of the corresponding content queries $\\mathcal{Q}_t^c$ .", + "bbox": [ + 76, + 719, + 468, + 779 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "It is notable that the initial position queries are densely spread throughout the 3D space. Also, every query aggregates features from its local region. This design choice makes it easier for the initial queries to capture the objects in a scene with a high recall, as shown in Fig. 3. It overcomes the low-recall issue caused by initial instance masks, and consequently reduces the training complexity of the subsequent layers.", + "bbox": [ + 75, + 780, + 468, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Relative Position Encoding. Other than the absolute position encoding (e.g., Fourier or sine transformations), we also adopt contextual relative position encoding in crossattention. Inspired by [28], we first calculate the relative positions $\\mathbf{r} \\in \\mathbb{R}^{n \\times N \\times 3}$ between the position queries $\\hat{\\mathcal{Q}}_t^p \\in \\mathbb{R}^{n \\times 3}$ and the global positions $\\mathcal{P} \\in \\mathbb{R}^{N \\times 3}$ , and quantize it into discrete integers $\\hat{\\mathbf{r}} \\in \\mathbb{Z}^{n \\times N \\times 3}$ as shown in Fig. 5. It is formulated as", + "bbox": [ + 498, + 90, + 890, + 210 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {r} = \\hat {\\mathcal {Q}} _ {t} ^ {p} - \\mathcal {P}, \\quad \\hat {\\mathbf {r}} = \\left\\lfloor \\frac {\\mathbf {r}}{s} \\right\\rfloor + \\frac {L}{2}, \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 589, + 218, + 890, + 246 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $s$ denotes the quantization size, $L$ denotes the length of position encoding table. We plus $\\frac{L}{2}$ to ensure the discrete relative positions are non-negative.", + "bbox": [ + 498, + 248, + 890, + 292 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Then, we use the discrete relative positions $\\hat{\\mathbf{r}}$ as indices to look up the corresponding position encoding tables $\\mathbf{t} \\in \\mathbb{R}^{3 \\times L \\times d}$ , as illustrated in Fig. 5. Formally, the relative position encoding $\\mathbf{f}^{pos} \\in \\mathbb{R}^{n \\times N \\times d}$ is yielded as", + "bbox": [ + 498, + 292, + 890, + 354 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {f} ^ {\\text {p o s}} = \\mathbf {t} [ 0, \\hat {\\mathbf {r}} _ {x} ] + \\mathbf {t} [ 1, \\hat {\\mathbf {r}} _ {y} ] + \\mathbf {t} [ 2, \\hat {\\mathbf {r}} _ {z} ], \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 573, + 363, + 890, + 380 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\hat{\\mathbf{r}}_x, \\hat{\\mathbf{r}}_y, \\hat{\\mathbf{r}}_z \\in \\mathbb{Z}^{n \\times N}$ are the discrete relative positions along the $x, y$ , and $z$ -axis, respectively.", + "bbox": [ + 498, + 388, + 890, + 419 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Further, the relative position encoding $\\mathbf{f}^{pos}$ performs dot product with the query features $\\mathbf{f}^q\\in \\mathbb{R}^{n\\times d}$ or key features $\\mathbf{f}^k\\in \\mathbb{R}^{N\\times d}$ in the cross-attention, which is formulated as", + "bbox": [ + 498, + 420, + 890, + 464 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {p o s} _ {-} \\mathbf {b i a s} _ {i, j} = \\mathbf {f} _ {i, j} ^ {p o s} \\cdot \\mathbf {f} _ {i} ^ {q} + \\mathbf {f} _ {i, j} ^ {p o s} \\cdot \\mathbf {f} _ {j} ^ {k}, \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 573, + 473, + 890, + 494 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\text{pos\\_bias} \\in \\mathbb{R}^{n \\times N}$ is the positional bias. It is then added to the cross-attention weights, followed by the softmax function, as shown in Fig. 4 (b).", + "bbox": [ + 498, + 502, + 890, + 547 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "It is worth noting that the RPE offers a greater degree of flexibility and error-insensitivity, compared to mask attention. In essence, RPE can be likened to a soft mask that has the ability to adjust attention weights flexibly, instead of hard masking. Another advantage of RPE is that it integrates semantic information (e.g., object size and class) and thus can harvest local information selectively. This is accomplished by the interaction between the relative positions and the semantic features (i.e., $\\mathbf{f}^q$ and $\\mathbf{f}^k$ ).", + "bbox": [ + 496, + 547, + 890, + 684 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Iterative Refinement. Since the content queries in our decoder layers are updated regularly, it is not optimal to maintain frozen position queries throughout the decoding process. Additionally, the initial position queries are static, so it is beneficial to adapt them to the specific input scene in the subsequent layers. To that end, we iteratively refine the position queries based on the content queries. Specifically, as shown in Fig. 4 (b), we leverage an MLP to predict a center offset $\\Delta p_{t}$ from the updated content query $Q_{t + 1}^{c}$ . We then add it to the previous position query $\\hat{Q}_t^p$ as", + "bbox": [ + 496, + 702, + 890, + 856 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\Delta p _ {t} = \\mathbf {M L P} _ {\\text {c e n t e r}} \\left(\\mathcal {Q} _ {t + 1} ^ {c}\\right), \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 601, + 864, + 890, + 888 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {\\mathcal {Q}} _ {t + 1} ^ {p} = \\hat {\\mathcal {Q}} _ {t} ^ {p} + \\Delta p _ {t}.\n$$\n", + "text_format": "latex", + "bbox": [ + 602, + 885, + 733, + 902 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "3696", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Center Matching & Loss. To eliminate the need for duplicate removal methods such as non-maximum suppression (NMS), bipartite matching is adopted during training. Existing works [49, 50] rely on semantic predictions and binary masks to match the ground truths.", + "bbox": [ + 75, + 90, + 468, + 167 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In contrast, to support center regression, we also incorporate center distance in bipartite matching. Since we require the queries to only attend to a local region, it is critical to ensure that they only match with nearby ground-truth objects. To achieve this, we adapt the matching costs formulation as follows", + "bbox": [ + 75, + 167, + 467, + 256 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {C} _ {c l s} (k, \\hat {k}) = \\mathrm {C E} (\\mathbf {C l a s s} _ {k}, \\hat {k}),\n$$\n", + "text_format": "latex", + "bbox": [ + 122, + 265, + 318, + 282 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {C} _ {d i c e} (k, \\hat {k}) = \\operatorname {D I C E} (\\mathbf {M a s k} _ {k}, \\mathbf {M a s k} _ {\\hat {k}}),\n$$\n", + "text_format": "latex", + "bbox": [ + 117, + 287, + 380, + 305 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {C} _ {b c e} (k, \\hat {k}) = \\operatorname {B C E} (\\mathbf {M a s k} _ {k}, \\mathbf {M a s k} _ {\\hat {k}}), \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 120, + 309, + 467, + 334 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {C} _ {\\text {c e n t e r}} (k, \\hat {k}) = \\mathrm {L} _ {1} (\\mathbf {C e n t e r} _ {k}, \\mathbf {C e n t e r} _ {\\hat {k}}), \\\\ \\mathcal {C} (k, \\hat {k}) = \\lambda_ {c l s} \\mathcal {C} _ {c l s} (k, \\hat {k}) + \\lambda_ {d i c e} \\mathcal {C} _ {d i c e} (k, \\hat {k}) \\\\ + \\lambda_ {b c e} \\mathcal {C} _ {b c e} (k, \\hat {k}) + \\lambda_ {c e n t e r} \\mathcal {C} _ {c e n t e r} (k, \\hat {k}), \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 102, + 330, + 424, + 391 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $k$ and $\\hat{k}$ denotes a predicted and ground-truth instance, respectively, $\\mathcal{C} \\in \\mathbb{R}^{n \\times n_{inst}}$ denotes the matching cost matrix, and $\\lambda$ denotes the cost weights.", + "bbox": [ + 75, + 404, + 467, + 449 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The Hungarian Algorithm is then applied on $\\mathcal{C}$ to yield the one-to-one matching result $\\hat{\\sigma} \\in \\mathbb{Z}^n$ , which is followed by the loss function as", + "bbox": [ + 75, + 450, + 467, + 494 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\hat {\\sigma} = \\arg \\min _ {\\sigma : \\sigma_ {i} \\neq \\sigma_ {j}, \\forall i \\neq j} \\sum_ {i = 1} ^ {n} \\mathcal {C} (i, \\sigma_ {i}), \\\\ \\mathcal {L} = \\lambda_ {c l s} \\operatorname {C E} \\left(\\operatorname {C l a s s} _ {i}, \\hat {\\sigma} _ {i}\\right) \\tag {10} \\\\ + \\lambda_ {d i c e} D I C E (\\mathbf {M a s k} _ {i}, \\mathbf {M a s k} _ {\\sigma_ {i}}) \\\\ + \\lambda_ {b c e} \\operatorname {B C E} \\left(\\mathbf {M a s k} _ {i}, \\mathbf {M a s k} _ {\\hat {\\sigma} _ {i}}\\right) \\\\ + \\lambda_ {c e n t e r} L _ {1} \\left(\\text {C e n t e r} _ {i}, \\text {C e n t e r} _ {\\hat {\\sigma} _ {i}}\\right). \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 138, + 506, + 467, + 619 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiment", + "text_level": 1, + "bbox": [ + 76, + 631, + 200, + 648 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "This section first provides an overview of the experimental setup in Sec. 4.1. We then present the 3D instance segmentation results in Sec. 4.2. Additionally, we conduct an extensive ablation study in Sec. 4.3. Furthermore, we showcase the object detection results and visual comparisons in Sections 4.4 and 4.5, respectively. Code and models will be made publicly available.", + "bbox": [ + 75, + 656, + 467, + 762 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Experimental Setting", + "text_level": 1, + "bbox": [ + 76, + 771, + 276, + 787 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Network Architecture. For both ScanNetv2 [14] and ScanNet200 [47], we follow previous works [50, 25, 55, 5, 33] to use 5-layer U-Net as the backbone. The initial channel is set to 32. Unless otherwise specified, we use the coordinates and colors as the input features. We use 6 layers of Transformer decoders, where the head number is set to 8 and the hidden and feed-forward dimensions are set", + "bbox": [ + 75, + 794, + 467, + 898 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "to 256 and 1024, respectively. We adopt Fourier absolute position encoding with the temperature set to 10,000. The quantization size for RPE is set to $0.1\\mathrm{m}$ , and the length of the RPE table is 48. Unless otherwise specified, we choose [50] as the baseline model, since it has achieved the best performance on ScanNetv2 val set so far. For the S3DIS [1] dataset, following Mask3D [49], we use Res16UNet34C [9] as the backbone and employ 4 decoders to attend to the coarsest four scales, and this is repeated 3 times with the shared parameters. The decoder hidden and feed-forward dimensions are set to 128 and 1024, respectively.", + "bbox": [ + 496, + 90, + 890, + 257 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Datasets. We use the ScanNetv2 [14], ScanNet200 [47] and S3DIS [1] datasets for evaluation. All of them are challenging large-scale indoor scene datasets.", + "bbox": [ + 496, + 275, + 890, + 320 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The ScanNetv2 dataset comprises 1201 scenes for training, and an additional 312 and 100 indoor scenes for validation and testing, respectively. The scenes are captured with RGB-D cameras and annotated with 20 semantic labels, 18 of which are instance classes. The ScanNet200 dataset adopts the same point cloud data, but it offers more diverse annotations, covering 200 classes, 198 of which are instance classes.", + "bbox": [ + 496, + 321, + 890, + 439 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The S3DIS dataset contains 271 rooms in 6 areas of three buildings, and 13 semantic categories are annotated. Following previous works, the scenes in Area 5 are used for validation and the others are for training.", + "bbox": [ + 496, + 441, + 890, + 502 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Implementation Details. We adopt one RTX 3090 GPU for training on ScanNet and ScanNet200, and one A100 GPU on S3DIS. Following previous works, we use AdamW [40] optimizer with the learning rate and weight decay set to 0.0001 and 0.05, respectively. We adopt poly scheduler on ScanNet and ScanNet200, and oncycle scheduler on S3DIS. The batch size is set to 4. For the weights of matching costs and losses, $(\\lambda_{cls}, \\lambda_{bce}, \\lambda_{dice}, \\lambda_{center})$ are set to (0.5, 1.0, 1.0, 0.5) on ScanNet and ScanNet200, and (2.0, 5.0, 1.0, 0.5) on S3DIS. The voxel size is set to $0.02\\mathrm{m}$ . We limit the points number up to 250,000. Otherwise, we crop the scene by cubic windows iteratively until the point number is lower than the limit. During inference, we select the top 100 instances with the highest scores and set the minimum points number per instance to 100.", + "bbox": [ + 496, + 520, + 890, + 747 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Instance Segmentation Results", + "text_level": 1, + "bbox": [ + 498, + 756, + 769, + 772 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "ScanNetv2. We present the results of instance segmentation on both the ScanNetv2 test and val sets in Tables 1 and 2, respectively. Our method achieves a considerable increase in mAP compared to previous works, suggesting a superior ability to capture fine-grained details and produce high-quality instance segmentation. While Mask3D [49] slightly outperforms our model in terms of $\\mathrm{mAP}_{50}$ , it is worth noting that this is potentially due to their use of a", + "bbox": [ + 496, + 779, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "3697", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/0c98aed4ea727396411b2029f81989d0e989517f0ec5091b0e2bdad15f01f5f8.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodmAP\\( \\mathrm{mAP}_{50} \\)bathbedbkshfcabinetchaircountercurtaindeskdoorotherpicturefridges. cur.sinksofatabletoiletwind.
3D-BoNet [2]25.348.851.932.425.113.734.53.141.96.916.213.15.220.233.814.730.130.365.117.8
MTML [26]28.240.257.738.018.210.743.00.142.25.717.916.27.022.951.116.149.131.365.016.2
GICN [38]34.163.858.037.134.419.846.95.256.49.321.221.212.734.753.720.652.532.972.924.1
3D-MPA [17]35.561.145.748.429.927.759.14.733.221.221.727.819.341.341.019.557.435.284.921.3
Dyco3D [20]39.564.164.251.844.725.966.65.025.116.623.136.223.233.153.522.958.743.885.031.7
PE [69]39.664.566.746.744.624.362.42.257.710.621.934.023.948.747.522.554.135.081.827.3
PointGroup [25]40.763.663.949.641.524.364.52.157.011.421.135.921.742.866.625.656.234.186.029.1
HAIS [5]45.769.970.456.145.736.467.34.654.719.430.842.628.845.471.126.256.343.488.934.4
OccuSeg [19]48.667.280.253.642.836.970.220.533.130.137.947.432.743.786.248.560.139.484.627.3
SoftGroup [55]50.476.166.757.937.238.169.47.267.730.338.753.131.958.275.431.864.349.290.738.8
SSTNet [33]50.669.873.854.949.731.669.317.837.719.833.046.357.651.585.749.463.745.794.329.0
SPFormer [50]54.977.074.564.048.439.573.931.156.633.546.849.255.547.874.743.671.254.089.334.3
Mask3D* [49]56.678.092.659.740.842.073.723.959.838.645.854.956.871.660.148.064.657.592.236.4
Ours57.877.477.864.952.044.976.125.358.439.153.047.261.749.979.547.374.554.896.037.4
\\( Ours^‡ \\)59.678.688.972.144.846.076.825.155.840.850.453.961.661.885.848.268.455.193.145.0
", + "bbox": [ + 78, + 89, + 895, + 318 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/ffc69739bd4205690c578deee1ff20a77747665cd7f2a1c64f76a9cbce30631d.jpg", + "table_caption": [ + "Table 1. 3D instance segmentation results on ScanNet test set. * denotes using Res16UNet34C (twice as many parameters as ours) as the backbone. ‡ denotes using surface normal. Methods published before the submission deadline (03/08/2023) are listed." + ], + "table_footnote": [], + "table_body": "
MethodmAP\\( \\mathrm{mAP}_{50} \\)
GSPN [67]19.337.8
MTML [26]20.340.2
3D-MPA [17]35.559.1
Dyco3D [20]35.457.6
PointGroup [25]34.856.7
MaskGroup [75]42.063.3
HAIS [5]43.564.1
OccuSeg [19]44.260.7
SoftGroup [55]46.067.6
SSTNet [33]49.464.3
SPFormer [50]56.373.9
Mask3D* [49]55.273.7
Ours58.475.9
\\( Ours^‡ \\)59.976.5
", + "bbox": [ + 80, + 372, + 465, + 614 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/5577de9bcfac08ae3f1c01f8a660f6bdc9fe5a39cf7351bd16c647e557619fe1.jpg", + "table_caption": [ + "Table 2. 3D instance segmentation results on ScanNet val set. * denotes using Res16UNet34C (twice as many parameters as ours) as the backbone. ‡ denotes using surface normal." + ], + "table_footnote": [], + "table_body": "
MethodmAP\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
\\( SPFormer^† \\)[50]25.233.839.6
\\( Mask3D* \\)[49]27.437.042.3
Ours29.238.243.3
", + "bbox": [ + 78, + 684, + 460, + 762 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "stronger backbone (i.e., Res16UNet34C with twice as many parameters as ours) and DBSCAN post-processing. Despite this, our approach produces significantly better performance on the ScanNetv2 val set than Mask3D, as seen in Table 2.", + "bbox": [ + 76, + 824, + 467, + 898 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/e9639cde441f92db7c8f6db4667f88c7e934096c4d1c5070edfb15c4aa9c34a1.jpg", + "table_caption": [ + "Table 3. 3D instance segmentation results on ScanNet200 val set. ${}^{ \\dagger }$ denotes reproduced results. * denotes using Res16UNet34C." + ], + "table_footnote": [], + "table_body": "
Method\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
PointGroup [25]57.8-
MaskGroup [75]65.0-
SoftGroup [55]66.1-
SSTNet [33]59.3-
SPFormer [50]66.8-
Mask3D [49]68.475.2
Ours69.175.7
", + "bbox": [ + 504, + 372, + 888, + 508 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 4. 3D instance segmentation results on S3DIS Area5.", + "bbox": [ + 500, + 518, + 852, + 534 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "ScanNet200. Table 3 presents our comparison with previous state-of-the-art methods on the val set of ScanNet200. Our method achieves a significant improvement in comparison to the other methods. Consistent conclusion is also seen on this challenging dataset. It is important to note that previous works employ mask attention, while our approach does not. This verifies the success of our auxiliary center regression task in replacing mask attention.", + "bbox": [ + 496, + 558, + 890, + 680 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "S3DIS. As shown in Table 4, our method is evaluated on S3DIS Area5. Our approach outperforms previous works. This consistently shows the superiority of our method.", + "bbox": [ + 496, + 698, + 890, + 744 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Ablation Study", + "text_level": 1, + "bbox": [ + 500, + 752, + 653, + 768 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We conduct an extensive ablation study to verify each component of our method as follows.", + "bbox": [ + 500, + 776, + 890, + 806 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Learnable Position Query. The position query aims to provide an explicit center representation to the content query counterpart. Making it learnable intends to learn an optimal initial spatial distribution. We notice that some previous works [49, 42] adopt non-parametric initial queries,", + "bbox": [ + 496, + 824, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "3698", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/0edad6df79495ad3017dd380634cbb5ab028077c15896be3efbcaba7ed186299.jpg", + "image_caption": [ + "(a)" + ], + "image_footnote": [], + "bbox": [ + 81, + 90, + 349, + 209 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/0d64127831112475c83b6176a852b03bacd2d0459dc637cc5f5a5962cc559a76.jpg", + "image_caption": [ + "Figure 6. Spatial distribution of ground truths that are matched to the same query at different training iterations. (a): Baseline. (b): Ours. We randomly select 10 object queries and record their matched ground-truth instances in the early training. The three scatter plots for each method represent the center XYZ coordinates of their matched ground-truth instances at different training iterations (the scatter points for a query correspond to different training iterations). More visualization details are given in supplementary material. Our method manifests strong positional matching consistency among different training iterations." + ], + "image_footnote": [], + "bbox": [ + 351, + 90, + 483, + 209 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/8abec5f17ba7e85a54a79f9db06931f258d6530af111400e265787719734ab24.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 486, + 90, + 617, + 209 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/5235d3b5118f3901a7cd038901c40dadcf3017a14e1f8e498621f0bf8dca2429.jpg", + "image_caption": [ + "(b)" + ], + "image_footnote": [], + "bbox": [ + 620, + 90, + 751, + 209 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/11fdca9eaf78ef11465e9fb216714abf81dd8ef8dcefdde63bf7b9846c226b75.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 754, + 90, + 885, + 209 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/ad92cd41d5912be765c1f00d84a0264753ccdbcfde54f707213e560ac152ec67.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
PositionContentmAP\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
FPSzero57.374.984.2
FPSlearnable57.175.083.4
learnablelearnable58.175.484.3
learnablezero58.475.984.5
", + "bbox": [ + 78, + 316, + 467, + 407 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/e5fb6759ef48436c1c40084a70b2ec171b0c38e2757b17cb6a02045e1cffcff6.jpg", + "table_caption": [ + "Table 5. Ablation study on different initializations for position and content queries." + ], + "table_footnote": [], + "table_body": "
Position EncodingmAP\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
No PE0.00.00.0
Fourier APE57.776.083.8
Content-conditioned APE58.075.784.3
RPE58.475.984.5
", + "bbox": [ + 78, + 455, + 468, + 547 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/f760a98fdbf59285ff480e1919da46d06990cba2de64ee524dbb01d9e18a9165.jpg", + "table_caption": [ + "Table 6. Ablation study on different position encodings." + ], + "table_footnote": [], + "table_body": "
IDiter. refinecenter matchcenter lossmAP\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
1✓✓57.575.384.0
2✓✓56.774.884.1
3✓✓56.874.684.5
4✓56.474.783.7
5✓✓✓58.475.984.5
", + "bbox": [ + 80, + 584, + 467, + 680 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 7. Ablation study on iterative refinement and center matching & loss.", + "bbox": [ + 76, + 686, + 468, + 715 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "where Furthest Point Sampling (FPS) is used to sample a number of points and transform them into position encodings via Fourier transformation followed by an MLP. We make comparisons in Table 5. The results show that learnable position query and zero-initialized content query perform best. A potential reason why 'FPS' lags behind 'learnable' is that the latter learns an optimal spatial distribution.", + "bbox": [ + 75, + 733, + 468, + 839 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Moreover, to show the pattern of the learnable position query, we visualize the spatial distribution of center coordinates of the matched ground truths for a query in Fig. 6. It shows that each query consistently attends to a local region.", + "bbox": [ + 75, + 839, + 468, + 901 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Relative Position Encoding. We compare various position encodings that are employed in previous works [49, 41], such as Fourier Absolute Position Encoding (APE) and the content query-conditioned APE. Specifically, the latter uses an MLP to project the content query into a $d$ -dim diagonal matrix, which then transforms the original absolute position encoding into a new one. It incorporates semantic information into the position encoding but does not consider relative relation. As shown in Table 6, RPE outperforms the others, which implies that both semantic information and relative relation are beneficial. Also, we notice that if we do not apply any position encoding, the training corrupts. This shows that positional prior is crucial in our framework.", + "bbox": [ + 496, + 319, + 890, + 515 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Iterative Refinement. We remove the iterative refinement and freeze the position query in all decoder layers, and we find that it causes a performance drop of $0.9\\%$ mAP as shown in the first row of Table 7. This verifies the effectiveness of iterative refinement.", + "bbox": [ + 496, + 532, + 890, + 608 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Center Matching & Loss. Moreover, to manifest the importance of center matching and center loss, we also conduct ablation studies in Table 7. We first remove the center matching and keep the center loss in the second row of the table, and we find that the performance drops by $1.7\\%$ mAP. Then we keep the center matching and remove the center loss. The performance also decreases by $1.6\\%$ mAP as shown in the 3-rd row. When both are absent, we observe an even larger performance drop $(2.0\\% \\mathrm{mAP})$ in the 4-th row. The results reveal that both center matching and loss are important to our framework.", + "bbox": [ + 496, + 627, + 890, + 792 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4. Object Detection Results", + "text_level": 1, + "bbox": [ + 500, + 801, + 725, + 816 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "The instance predictions of instance segmentation can be easily transformed into bounding box predictions, by obtaining the minimum and maximum coordinates of the masked instances. We empirically find that the generated object detection results from the instance predictions work", + "bbox": [ + 496, + 824, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "3699", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/aff190b6b9477aeeab9ba6519fdd0de0bfdbf48ee560fb2b20d10d5f0c6345d3.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 86, + 87, + 885, + 508 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/15f26af3227e222071d868efb4bcee83c2ccb9591443ad67ad93bba8bbdc9971.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Methodtaskbox mAP50box mAP25
VoteNet [44]det33.558.6
HGNet [4]det34.461.3
MLCVNet [65]det41.464.5
GSDN [18]det34.862.8
H3DNet [72]det48.167.2
3DETR [42]det47.065.0
Group-free [39]det52.869.1
RBGNet [57]det55.270.6
HyperDet3D [74]det57.270.9
FCAF3D [48]det57.371.5
CAGroup3D [56]det61.375.1
3D-MPA [17]inst49.264.2
Mask3D [49]inst56.270.2
Oursinst63.973.5
", + "bbox": [ + 106, + 516, + 434, + 712 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 8. 3D object detection results on ScanNetv2. For methods designed for the instance segmentation task, the bounding boxes are generated by the instance mask predictions.", + "bbox": [ + 75, + 715, + 468, + 758 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "significantly better than previous methods tailored for 3D object detection in terms of $\\mathrm{mAP}_{50}$ , as shown in Table 8. This finding also shows that our approach outputs high-quality instance segmentation results with fewer artifacts.", + "bbox": [ + 75, + 771, + 468, + 833 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.5. Visual Comparison", + "text_level": 1, + "bbox": [ + 76, + 845, + 261, + 862 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We visually compare our approach with previous state-of-the-art methods in Fig. 7. More examples are given in", + "bbox": [ + 75, + 869, + 468, + 902 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "the supplementary material. The visualizations demonstrate that our method tends to correctly recognize the classes of the instances. It implies that our approach is able to generate more high-quality instance segmentation results.", + "bbox": [ + 498, + 518, + 892, + 580 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 597, + 617, + 613 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this work, we have presented a mask-attention-free transformer for the 3D instance segmentation task. We first observe the issue of low-recall of the initial masks in existing works. It adds training difficulty and slows down convergence. We thus avoid using mask attention and instead propose an auxiliary center regression task to guide the cross-attention. To fit center regression, we develop a series of designs. A dense distribution of position queries is learned to yield a higher recall of the perceived instances. Also, relative position encoding and iterative refinement are designed to further boost the performance. Each component is verified to be effective.", + "bbox": [ + 496, + 625, + 892, + 805 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgements", + "text_level": 1, + "bbox": [ + 500, + 816, + 666, + 834 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "This work was supported in part by the Research Grants Council under the Areas of Excellence scheme grant AoE/E-601/22-R and Shenzhen Science and Technology Program KQTD20210811090149095.", + "bbox": [ + 498, + 840, + 892, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "3700", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Iro Armeni, Ozan Sener, Amir R. Zamir, Helen Jiang, Ioannis Brilakis, Martin Fischer, and Silvio Savarese. 3d semantic parsing of large-scale indoor spaces. In CVPR, 2016. 2, 5", + "[2] Yang Bo, Wang Jianan, Clark Ronald, Hu Qingyong, Wang Sen, Markham Andrew, and Trigoni Niki. Learning object bounding boxes for 3d instance segmentation on point clouds. In NeurIPS, pages 6737-6746, 2019. 2, 6", + "[3] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In ECCV, 2020. 3", + "[4] Jintai Chen, Biwen Lei, Qingyu Song, Haochao Ying, Danny Z Chen, and Jian Wu. A hierarchical graph network for 3d object detection on point clouds. In CVPR, 2020. 8", + "[5] Shaoyu Chen, Jiemin Fang, Qian Zhang, Wenyu Liu, and Xinggang Wang. Hierarchical aggregation for 3d instance segmentation. In ICCV, pages 15467-15476, 2021. 1, 2, 5, 6", + "[6] Yukang Chen, Yanwei Li, Xiangyu Zhang, Jian Sun, and Jiaya Jia. Focal sparse convolutional networks for 3d object detection. In CVPR, 2022. 2", + "[7] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In CVPR, 2022. 3", + "[8] Bowen Cheng, Alex Schwing, and Alexander Kirillov. Per-pixel classification is not all you need for semantic segmentation. NeurIPS, 2021. 3", + "[9] Christopher Choy, JunYoung Gwak, and Silvio Savarese. 4d spatio-temporal convnets: Minkowski convolutional neural networks. In CVPR, 2019. 5", + "[10] Ruihang Chu, Yukang Chen, Tao Kong, Lu Qi, and Lei Li. Icm-3d: Instantiated category modeling for 3d instance segmentation. IEEE Robotics and Automation Letters, 7(1):57-64, 2021. 2", + "[11] Ruihang Chu, Zhengzhe Liu, Xiaqing Ye, Xiao Tan, Xiaojuan Qi, Chi-Wing Fu, and Jiaya Jia. Command-driven articulated object understanding and manipulation. In CVPR, 2023. 2", + "[12] Ruihang Chu, Xiaqing Ye, Zhengzhe Liu, Xiao Tan, Xiaojuan Qi, Chi-Wing Fu, and Jiaya Jia. Twist: Two-way inter-label self-training for semi-supervised 3d instance segmentation. In CVPR, 2022. 2", + "[13] Xiangxiang Chu, Zhi Tian, Yuqing Wang, Bo Zhang, Haibing Ren, Xiaolin Wei, Huaxia Xia, and Chunhua Shen. Twins: Revisiting the design of spatial attention in vision transformers. arXiv:2104.13840, 2021. 3", + "[14] Angela Dai, Angel X. Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In CVPR, 2017. 2, 5", + "[15] Xiaoyi Dong, Jianmin Bao, Dongdong Chen, Weiming Zhang, Nenghai Yu, Lu Yuan, Dong Chen, and Baining Guo. Cswin transformer: A general vision transformer backbone with cross-shaped windows. arXiv:2107.00652, 2021. 3" + ], + "bbox": [ + 78, + 114, + 468, + 898 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[16] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. ICLR, 2021. 3", + "[17] Francis Engelmann, Martin Bokeloh, Alireza Fathi, Bastian Leibe, and Matthias Nießner. 3d-mpa: Multi-proposal aggregation for 3d semantic instance segmentation. In CVPR, pages 9031-9040, 2020. 2, 6, 8", + "[18] JunYoung Gwak, Christopher Choy, and Silvio Savarese. Generative sparse detection networks for 3d single-shot object detection. In ECCV, 2020. 8", + "[19] Lei Han, Tian Zheng, Lan Xu, and Lu Fang. Occuseg: Occupancy-aware 3d instance segmentation. In CVPR, pages 2940-2949, 2020. 2, 6", + "[20] Tong He, Chunhua Shen, and Anton van den Hengel. Dyco3d: Robust instance segmentation of 3d point clouds through dynamic convolution. In CVPR, pages 354-363, 2021. 2, 6", + "[21] Ji Hou, Angela Dai, and Matthias Nießner. 3d-sis: 3d semantic instance segmentation of rgb-d scans. In CVPR, pages 4421-4430, 2019. 2", + "[22] Ding Jia, Yuhui Yuan, Haodi He, Xiaopei Wu, Haojun Yu, Weihong Lin, Lei Sun, Chao Zhang, and Han Hu. Detrs with hybrid matching. arXiv preprint, 2022. 3", + "[23] Haiyong Jiang, Feilong Yan, Jianfei Cai, Jianmin Zheng, and Jun Xiao. End-to-end 3d point cloud instance segmentation without detection. In CVPR, pages 12796-12805, 2020. 2", + "[24] Li Jiang, Shaoshuai Shi, Zhuotao Tian, Xin Lai, Shu Liu, Chi-Wing Fu, and Jiaya Jia. Guided point contrastive learning for semi-supervised point cloud semantic segmentation. In ICCV, 2021. 2", + "[25] Li Jiang, Hengshuang Zhao, Shaoshuai Shi, Shu Liu, ChiWing Fu, and Jiaya Jia. Pointgroup: Dual-set point grouping for 3d instance segmentation. In CVPR, pages 4867-4876, 2020. 1, 2, 5, 6", + "[26] Jean Lahoud, Bernard Ghanem, Marc Pollefeys, and Martin R Oswald. 3d instance segmentation via multi-task metric learning. In ICCV, pages 9256-9266, 2019. 2, 6", + "[27] Xin Lai, Yukang Chen, Fanbin Lu, Jianhui Liu, and Jiaya Jia. Spherical transformer for lidar-based 3d recognition. In CVPR, 2023. 2", + "[28] Xin Lai, Jianhui Liu, Li Jiang, Liwei Wang, Hengshuang Zhao, Shu Liu, Xiaojuan Qi, and Jiaya Jia. Stratified transformer for 3d point cloud segmentation. In CVPR, 2022. 2, 3, 4", + "[29] Feng Li, Hao Zhang, Shilong Liu, Jian Guo, Lionel M Ni, and Lei Zhang. Dn-detr: Accelerate detr training by introducing query denoising. In CVPR, 2022. 3", + "[30] Feng Li, Hao Zhang, Shilong Liu, Lei Zhang, Lionel M Ni, Heung-Yeung Shum, et al. Mask dino: Towards a unified transformer-based framework for object detection and segmentation. arXiv preprint, 2022. 3", + "[31] Yanwei Li, Yilun Chen, Xiaojuan Qi, Zeming Li, Jian Sun, and Jiaya Jia. Unifying voxel-based representation with transformer for 3d object detection. NeurIPS, 2022. 2" + ], + "bbox": [ + 501, + 92, + 890, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "3701", + "bbox": [ + 482, + 945, + 513, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[32] Yanwei Li, Xiaojuan Qi, Yukang Chen, Liwei Wang, Zeming Li, Jian Sun, and Jiaya Jia. Voxel field fusion for 3d object detection. In CVPR, 2022. 2", + "[33] Zhihao Liang, Zhihao Li, Songcen Xu, Mingkui Tan, and Kui Jia. Instance segmentation in 3d scenes using semantic superpoint tree networks. In ICCV, 2021. 2, 5, 6", + "[34] Jiahui Liu, Chirui Chang, Jianhui Liu, Xiaoyang Wu, Lan Ma, and Xiaojuan Qi. Mars3d: A plug-and-play motion-aware model for semantic segmentation on multi-scan 3d point clouds. In CVPR, 2023. 2", + "[35] Jianhui Liu, Yukang Chen, Xiaqing Ye, and Xiaojuan Qi. Prior-free category-level pose estimation with implicit space transformation. arXiv preprint arXiv:2303.13479, 2023. 2", + "[36] Jianhui Liu, Yukang Chen, Xiaqing Ye, Zhuotao Tian, Xiao Tan, and Xiaojuan Qi. Spatial pruned sparse convolution for efficient 3d object detection. NeurIPS, 2022. 2", + "[37] Shilong Liu, Feng Li, Hao Zhang, Xiao Yang, Xianbiao Qi, Hang Su, Jun Zhu, and Lei Zhang. Dab-detr: Dynamic anchor boxes are better queries for detr. In ICLR, 2022. 3", + "[38] Shih-Hung Liu, Shang-Yi Yu, Shao-Chi Wu, Hwann-Tzong Chen, and Tyng-Luh Liu. Learning gaussian instance segmentation in point clouds. arXiv preprint, 2020. 6", + "[39] Ze Liu, Zheng Zhang, Yue Cao, Han Hu, and Xin Tong. Group-free 3d object detection via transformers. In ICCV, 2021. 3, 8", + "[40] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. arXiv:1711.05101, 2017. 5", + "[41] Depu Meng, Xiaokang Chen, Zejia Fan, Gang Zeng, Houqiang Li, Yuhui Yuan, Lei Sun, and Jingdong Wang. Conditional detr for fast training convergence. In ICCV, 2021. 3, 7", + "[42] Ishan Misra, Rohit Girdhar, and Armand Joulin. An end-to-end transformer model for 3d object detection. In ICCV, 2021. 6, 8", + "[43] Chunghyun Park, Yoonwoo Jeong, Minsu Cho, and Jaesik Park. Fast point transformer. In CVPR, 2022. 3", + "[44] Charles R Qi, Or Litany, Kaiming He, and Leonidas J Guibas. Deep hough voting for 3d object detection in point clouds. In ICCV, 2019. 8", + "[45] Charles R Qi, Hao Su, Kaichun Mo, and Leonidas J Guibas. Pointnet: Deep learning on point sets for 3d classification and segmentation. In CVPR, 2017. 2", + "[46] Charles Ruizhongtai Qi, Li Yi, Hao Su, and Leonidas J Guibas. Pointnet++: Deep hierarchical feature learning on point sets in a metric space. NeurIPS, 2017. 2", + "[47] David Rozenberszki, Or Litany, and Angela Dai. Language-grounded indoor 3d semantic segmentation in the wild. In ECCV, 2022. 5", + "[48] Danila Rukhovich, Anna Vorontsova, and Anton Konushin. Fcaf3d: fully convolutional anchor-free 3d object detection. In ECCV, 2022. 8", + "[49] Jonas Schult, Francis Engelmann, Alexander Hermans, Or Litany, Siyu Tang, and Bastian Leibe. Mask3d for 3d semantic instance segmentation. ICRA, 2023. 1, 2, 3, 4, 5, 6, 7, 8", + "[50] Jiahao Sun, Chunmei Qing, Junpeng Tan, and Xiangmin Xu. Superpoint transformer for 3d scene instance segmentation. AAAI, 2023. 1, 2, 3, 4, 5, 6" + ], + "bbox": [ + 78, + 90, + 468, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[51] Shuyang Sun, Xiaoyu Yue, Song Bai, and Philip Torr. Visual parser: Representing part-whole hierarchies with transformers. arXiv:2107.05790, 2021. 3", + "[52] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Herve Jegou. Training data-efficient image transformers & distillation through attention. In ICML, 2021. 3", + "[53] Hugo Touvron, Matthieu Cord, Alexandre Sablayrolles, Gabriel Synnaeve, and Hervé Jégou. Going deeper with image transformers. arXiv:2103.17239, 2021. 3", + "[54] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In NeurIPS, 2017. 2", + "[55] Thang Vu, Kookhoi Kim, Tung M Luu, Thanh Nguyen, and Chang D Yoo. Softgroup for 3d instance segmentation on point clouds. In CVPR, 2022. 1, 2, 5, 6", + "[56] Haiyang Wang, Lihe Ding, Shaocong Dong, Shaoshuai Shi, Aoxue Li, Jianan Li, Zhenguo Li, and Liwei Wang. Cagroup3d: Class-aware grouping for 3d object detection on point clouds. In NeurIPS, 2022. 8", + "[57] Haiyang Wang, Shaoshuai Shi, Ze Yang, Rongyao Fang, Qi Qian, Hongsheng Li, Bernt Schiele, and Liwei Wang. Rbgnet: Ray-based grouping for 3d object detection. In CVPR, 2022. 8", + "[58] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pvtv2: Improved baselines with pyramid vision transformer. arXiv:2106.13797, 2021. 3", + "[59] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In ICCV, 2021. 3", + "[60] Weiyue Wang, Ronald Yu, Qiangui Huang, and Ulrich Neumann. Sgpn: Similarity group proposal network for 3d point cloud instance segmentation. In CVPR, pages 2569-2578, 2018. 2", + "[61] Xinlong Wang, Shu Liu, Xiaoyong Shen, Chunhua Shen, and Jiaya Jia. Associatively segmenting instances and semantics in point clouds. In CVPR, pages 4096-4105, 2019. 2", + "[62] Yingming Wang, Xiangyu Zhang, Tong Yang, and Jian Sun. Anchor detr: Query design for transformer-based detector. In AAAI, 2022. 3", + "[63] Wenxuan Wu, Qi Shan, and Li Fuxin. Pointconvformer: Re-venge of the point-based convolution. arXiv preprint, 2022. 3", + "[64] Xiaoyang Wu, Yixing Lao, Li Jiang, Xihui Liu, and Hengshuang Zhao. Point transformer v2: Grouped vector attention and partition-based pooling. NeurIPS, 2022. 3", + "[65] Qian Xie, Yu-Kun Lai, Jing Wu, Zhoutao Wang, Yiming Zhang, Kai Xu, and Jun Wang. Mlcvnet: Multi-level context votenet for 3d object detection. In CVPR, 2020. 8", + "[66] Jianwei Yang, Chunyuan Li, Pengchuan Zhang, Xiyang Dai, Bin Xiao, Lu Yuan, and Jianfeng Gao. Focal self-attention for local-global interactions in vision transformers. In NeurIPS, 2021. 3", + "[67] Li Yi, Wang Zhao, He Wang, Minhyuk Sung, and Leonidas J Guibas. Gspn: Generative shape proposal network for 3d" + ], + "bbox": [ + 501, + 90, + 890, + 901 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "3702", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "instance segmentation in point cloud. In CVPR, pages 3947-3956, 2019. 2, 6", + "[68] Qihang Yu, Huiyu Wang, Siyuan Qiao, Maxwell Collins, Yukun Zhu, Hartwig Adam, Alan Yuille, and Liang-Chieh Chen. k-means mask transformer. In ECCV, 2022. 3", + "[69] Biao Zhang and Peter Wonka. Point cloud instance segmentation using probabilistic embeddings. In CVPR, pages 8883-8892, 2021. 2, 6", + "[70] Gongjie Zhang, Zhipeng Luo, Yingchen Yu, Kaiwen Cui, and Shijian Lu. Accelerating detr convergence via semantic-aligned matching. In CVPR, 2022. 3", + "[71] Hao Zhang, Feng Li, Shilong Liu, Lei Zhang, Hang Su, Jun Zhu, Lionel Ni, and Harry Shum. Dino: Detr with improved denoising anchor boxes for end-to-end object detection. In ICLR, 2022. 3", + "[72] Zaiwei Zhang, Bo Sun, Haitao Yang, and Qixing Huang. H3dnet: 3d object detection using hybrid geometric primitives. In ECCV, 2020. 8", + "[73] Hengshuang Zhao, Li Jiang, Jiaya Jia, Philip HS Torr, and Vladlen Koltun. Point transformer. In ICCV, 2021. 3", + "[74] Yu Zheng, Yueqi Duan, Jiwen Lu, Jie Zhou, and Qi Tian. Hyperdet3d: Learning a scene-conditioned 3d object detector. In CVPR, 2022. 8", + "[75] Min Zhong, Xinghao Chen, Xiaokang Chen, Gang Zeng, and Yunhe Wang. Maskgroup: Hierarchical point grouping and masking for 3d instance segmentation. In ICME, 2022. 1, 6", + "[76] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable detr: Deformable transformers for end-to-end object detection. In ICLR, 2020. 3" + ], + "bbox": [ + 78, + 90, + 468, + 503 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "3703", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/2a13e96b-8070-4a45-a596-f26ce5eefa9a_model.json b/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/2a13e96b-8070-4a45-a596-f26ce5eefa9a_model.json new file mode 100644 index 0000000000000000000000000000000000000000..fd6889b137a73a1ed66425bae37a104f3d9fc768 --- /dev/null +++ b/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/2a13e96b-8070-4a45-a596-f26ce5eefa9a_model.json @@ -0,0 +1,2532 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.158, + 0.131, + 0.815, + 0.154 + ], + "angle": 0, + "content": "Mask-Attention-Free Transformer for 3D Instance Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.093, + 0.179, + 0.47, + 0.22 + ], + "angle": 0, + "content": "Xin Lai1 Yuhui Yuan3 Ruihang Chu1 \n1The Chinese University of Hong Kong" + }, + { + "type": "text", + "bbox": [ + 0.481, + 0.179, + 0.884, + 0.217 + ], + "angle": 0, + "content": "Yukang Chen\\(^{1}\\) Han Hu\\(^{3}\\) Jiaya Jia\\(^{1,2*}\\) \n\\(^{2}\\)SmartMore \\({ }^{3}\\)Microsoft Research Asia" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.252, + 0.314, + 0.268 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.283, + 0.474, + 0.661 + ], + "angle": 0, + "content": "Recently, transformer-based methods have dominated 3D instance segmentation, where mask attention is commonly involved. Specifically, object queries are guided by the initial instance masks in the first cross-attention, and then iteratively refine themselves in a similar manner. However, we observe that the mask-attention pipeline usually leads to slow convergence due to low-recall initial instance masks. Therefore, we abandon the mask attention design and resort to an auxiliary center regression task instead. Through center regression, we effectively overcome the low-recall issue and perform cross-attention by imposing positional prior. To reach this goal, we develop a series of position-aware designs. First, we learn a spatial distribution of 3D locations as the initial position queries. They spread over the 3D space densely, and thus can easily capture the objects in a scene with a high recall. Moreover, we present relative position encoding for the cross-attention and iterative refinement for more accurate position queries. Experiments show that our approach converges \\(4\\times\\) faster than existing work, sets a new state of the art on ScanNetv2 3D instance segmentation benchmark, and also demonstrates superior performance across various datasets. Code and models are available at https://github.com/dvlab-research/Mask-Attention-Free-Transformer." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.688, + 0.21, + 0.704 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.713, + 0.47, + 0.805 + ], + "angle": 0, + "content": "Nowadays 3D point clouds can be conveniently collected. They have benefited various applications, such as autonomous driving, robotics, and augmented reality. As a fundamental task, 3D instance segmentation also poses great challenges simultaneously, such as geometric occlusion and semantic ambiguity." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.805, + 0.471, + 0.88 + ], + "angle": 0, + "content": "Many works have been proposed to solve the 3D instance segmentation task. Grouping-based methods [25, 55, 5, 75] rely on heuristic clustering algorithms such as DBSCAN or Breadth-First Search (BFS) to generate instance proposals. They thus require sophisticated hyper-parameters" + }, + { + "type": "image", + "bbox": [ + 0.517, + 0.254, + 0.877, + 0.479 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.481, + 0.895, + 0.524 + ], + "angle": 0, + "content": "Figure 1. Validation curve of the baseline and ours on ScanNetv2 val set. With only 128-epoch training, ours outperforms the baseline trained with 512 epochs." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.539, + 0.895, + 0.689 + ], + "angle": 0, + "content": "tuning and are prone to wrongly segment instances that are close to each other. Recently, transformer-based methods [49, 50] develop a fully end-to-end pipeline. With transformer decoder layers, a fixed number of object queries attend to global features iteratively and directly output instance predictions. It requires no post-processing for duplicate removal such as NMS, since it adopts one-to-one bipartite matching during training. Moreover, it employs mask attention, which uses the instance masks predicted in the last layer to guide the cross-attention." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.69, + 0.896, + 0.902 + ], + "angle": 0, + "content": "However, we point out that current transformer-based methods suffer from the issue of slow convergence. As shown in Fig. 1, the baseline model manifests slow convergence and lags behind our method by a large margin, particularly in the early stages of training. We dive further and find that the issue is potentially caused by the low recall of the initial instance masks. Specifically, as shown in Fig. 2 (a), the initial instance masks are produced by the similarity map between the initial object queries and the point-wise mask features. Since the initial object queries are unstable in early training, we notice that the recall of initial instance masks is substantially lower than ours in Fig. 3, especially at the beginning of training (i.e., the 32-th epoch). The low-quality initial instance masks increase the training difficulty," + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.888, + 0.225, + 0.9 + ], + "angle": 0, + "content": "*Corresponding Author" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3693" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.09, + 0.468, + 0.199 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.202, + 0.47, + 0.258 + ], + "angle": 0, + "content": "Figure 2. The framework of (a) existing works (based on mask attention) and (b) ours. Existing works have the issue of low-recall initial instance masks (i.e., \\(\\mathcal{M}_0\\)). Our approach resorts to an auxiliary center regression task to circumvent this issue." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.277, + 0.316, + 0.291 + ], + "angle": 0, + "content": "thereby slowing down convergence." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.292, + 0.469, + 0.473 + ], + "angle": 0, + "content": "Given the low recall of the initial instance masks, we abandon the mask attention design and instead construct an auxiliary center regression task to guide cross-attention, as depicted in Fig. 2 (b). To enable center regression, we develop a series of position-aware designs. Firstly, we maintain a set of learnable position queries, each of which denotes the position of its corresponding content query. They are densely distributed over the 3D space, and we require each query to attend to its local region. As a result, the queries can easily capture the objects in a scene with a higher recall, which is crucial in reducing training difficulty and accelerating convergence." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.473, + 0.469, + 0.593 + ], + "angle": 0, + "content": "In addition, we design the contextual relative position encoding for cross-attention. Compared to the mask attention used in previous works, our solution is more flexible since the attention weights are adjusted by relative positions instead of hard masking. Furthermore, we iteratively update the position queries to achieve more accurate representation. Finally, we introduce the center distances between predictions and ground truths in both matching and loss." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.594, + 0.349, + 0.607 + ], + "angle": 0, + "content": "In total, our contribution is three-fold." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.616, + 0.468, + 0.66 + ], + "angle": 0, + "content": "- We observe that existing transformer-based methods suffer from the low recall of initial instance masks, which causes training difficulty and slow convergence." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.67, + 0.469, + 0.745 + ], + "angle": 0, + "content": "Instead of relying on mask attention, we construct an auxiliary center regression task to overcome the lowrecall issue and design a series of position-aware components accordingly. Our approach manifests faster convergence and demonstrates higher performance." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.754, + 0.468, + 0.813 + ], + "angle": 0, + "content": "- Experiments show our approach achieves a new state-of-the-art result and demonstrates superior performance on various datasets including ScanNetv2, ScanNet200, and S3DIS." + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.616, + 0.469, + 0.813 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.822, + 0.219, + 0.837 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.848, + 0.314, + 0.864 + ], + "angle": 0, + "content": "2.1. 3D Instance Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.871, + 0.469, + 0.901 + ], + "angle": 0, + "content": "3D instance segmentation is a fundamental task for 3D recognition [45, 46, 28, 6, 32, 36, 31, 35, 27, 24, 34," + }, + { + "type": "image", + "bbox": [ + 0.527, + 0.098, + 0.871, + 0.301 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.304, + 0.892, + 0.387 + ], + "angle": 0, + "content": "Figure 3. The recall of initial instance masks at the 32-th and 80-th training epoch. We compare the baseline trained with 512 epochs and ours trained with 128, 256, and 512 epochs. Since our approach does not produce initial instance masks before entering decoder layers, we make statistics on the instance masks output by the first decoder layer for both the baseline and ours." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.409, + 0.892, + 0.817 + ], + "angle": 0, + "content": "11]. The solutions can be categorized into detection-based, grouping-based and the new emerging transformer-based paradigms. Detection-based approaches [21, 2, 67] first detect the bounding boxes and then segment the fine-grained instance mask. On the other hand, grouping-based approaches [60, 61, 26, 17, 19, 25, 23, 20, 69, 33, 5, 55, 12, 10] employ clustering algorithms to group the points into a set of instance clusters. Before clustering, they either move 3D points towards the associated object center to form a more compact distribution [26, 19, 25, 23, 69, 33, 5, 55], or transform points to a high-dimension feature space [60, 61]. Further, a series of works leverage semantic priors to avoid the noisy points from other categories [26, 25, 33, 5, 55] or use advanced grouping strategies [55, 5, 33]. With these designs, the grouping-based paradigm has achieved leading performance across various evaluation benchmarks[1, 14] for a long time. Recently, transformer-based paradigm [49, 50] becomes another option and swiftly sets a new state-of-the-art. Compared with previous methods, it presents an elegant pipeline, and can directly output instance predictions. It relies on the transformer decoder and mask attention to aggregate information from global features. In this work, we construct an auxiliary center regression task to assist in cross-attention. Although the existing grouping-based methods also predict center offsets, we explain that ours is not for instance proposals, but to overcome the lowrecall issue and provide positional priors for cross-attention." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.831, + 0.688, + 0.845 + ], + "angle": 0, + "content": "2.2. Vision Transformer" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Transformer has become a fundamental model in the vision area, thanks to its flexibility and power to model various scenarios using attention mechanisms [54]. Re" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3694" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.09, + 0.89, + 0.369 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.371, + 0.893, + 0.427 + ], + "angle": 0, + "content": "Figure 4. The overview of our framework. Besides content queries \\(\\mathcal{Q}_0^c\\), we also maintain a set of learnable position queries \\(\\mathcal{Q}_0^p\\). The content queries \\(\\mathcal{Q}^c\\) aggregate features from the global features \\(\\mathcal{F}\\). The position queries \\(\\mathcal{Q}^p\\) are designed to guide the cross-attention. The attention weights are adjusted based on the relative positions between the position queries \\(\\mathcal{Q}^p\\) and the global positions \\(\\mathcal{P}\\). Both content and position queries are iteratively refined in each layer. Only 3 decoder layers are shown (we use 6 layers in our experiments)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.448, + 0.473, + 0.75 + ], + "angle": 0, + "content": "cently, many works [16, 52, 53, 59, 58, 13, 15, 51, 66] rely on the self-attention in transformers to develop vision fundamental models. Besides, DETR [3] proposes a fully end-to-end pipeline for object detection. It utilizes transformer decoders to dynamically aggregate features from images, and uses one-to-one bipartite matching for ground-truth assignment, yielding an elegant pipeline. To solve the notorious slow convergence of DETR, approaches [76, 62, 41, 37, 70, 68] propose deformable attention, impose strong prior or decrease searching space in cross-attention to accelerate convergence. Further, methods of [29, 39, 22, 71, 30] present several ways to stabilize matching and training. Moreover, masked attention [8, 7] are proposed to impose semantic priors to accelerate training for segmentation tasks. Recently, there are works [28, 73, 63, 64, 43, 49, 50] that develop transformer models tailored for 3D point clouds. Following this line of research, we observe the low recall of initial instance masks, and present solutions to circumvent the use of mask attention." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.765, + 0.168, + 0.78 + ], + "angle": 0, + "content": "3. Method" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.791, + 0.47, + 0.837 + ], + "angle": 0, + "content": "We first review previous methods and present the overview of our method in Sec. 3.1. Then, we elaborate on the details of our position-aware designs in Sec. 3.2." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.847, + 0.188, + 0.861 + ], + "angle": 0, + "content": "3.1. Overview" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.871, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Preliminary. Recently, Mask3D [49] and SPFormer [50] present a fully end-to-end pipeline, which allows the object" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.448, + 0.895, + 0.646 + ], + "angle": 0, + "content": "queries to directly output instance predictions. With transformer decoders, a fixed number of object queries aggregate information from the global features (either multi-scale voxel features [49] or superpoint features [50]) extracted with the backbone. Moreover, similar to Mask2Former [8, 7], they adopt mask attention and rely on the instance masks to guide the cross-attention. Specifically, the cross-attention is masked with the instance masks predicted in the last decoder layer, so that the queries only need to consider the masked features. However, as shown in Fig. 3, the recall of initial instance masks is low in the early stages of training. It hinders the ability to achieve a high-quality result in the subsequent layers and thus increases training difficulty." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.659, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Ours. Instead of relying on mask attention, we propose an auxiliary center regression task to guide instance segmentation. The overview of our method is shown in Fig. 4 (a). We first yield the global positions \\(\\mathcal{P} \\in \\mathbb{R}^{N \\times 3}\\) from the input point cloud and extract the global features \\(\\mathcal{F} \\in \\mathbb{R}^{N \\times d}\\) using the backbone (\\(\\mathcal{P}\\) and \\(\\mathcal{F}\\) can be either voxels [49] or superpoints [50] positions and features). In contrast to existing works, besides the content queries \\(\\mathcal{Q}_0^c \\in \\mathbb{R}^{n \\times d}\\), we also maintain a fixed number of position queries \\(\\mathcal{Q}_0^p \\in [0,1]^{n \\times 3}\\) that represent the normalized instance centers. \\(\\mathcal{Q}_0^p\\) is randomly initialized and \\(\\mathcal{Q}_0^c\\) is initialized with zero. Given the global positions \\(\\mathcal{P}\\) and global features \\(\\mathcal{F}\\), our goal is to let the positional queries guide their corresponding content queries in cross-attention, and then iteratively refine both sets of queries, and finally predict the instance centers, classes and masks. For the \\(t\\)-th decoder layer, this process" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.958 + ], + "angle": 0, + "content": "3695" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.089, + 0.468, + 0.202 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.207, + 0.47, + 0.235 + ], + "angle": 0, + "content": "Figure 5. The illustration for relative position encoding. We note the shape of the corresponding tensor at the bottom." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.261, + 0.188, + 0.275 + ], + "angle": 0, + "content": "is formulated as" + }, + { + "type": "equation", + "bbox": [ + 0.142, + 0.288, + 0.47, + 0.307 + ], + "angle": 0, + "content": "\\[\n\\mathbf {C e n t e r} _ {t} = \\mathbf {M L P} _ {\\text {c e n t e r}} \\left(\\mathbf {Q} _ {t} ^ {c}\\right) + \\mathbf {Q} _ {t - 1} ^ {p}, \\tag {1}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.188, + 0.333, + 0.469, + 0.351 + ], + "angle": 0, + "content": "\\[\n\\mathbf {C l a s s} _ {t} = \\mathbf {M L P} _ {c l s} \\left(\\mathbf {Q} _ {t} ^ {c}\\right), \\tag {2}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.078, + 0.383, + 0.482, + 0.414 + ], + "angle": 0, + "content": "\\[\n\\mathbf {M a s k} _ {t} = \\sigma \\left(\\mathbf {Q} _ {t} ^ {c} \\cdot \\mathcal {F} _ {\\text {m a s k}} ^ {T}\\right) < 0. 5, \\mathcal {F} _ {\\text {m a s k}} = \\mathbf {M L P} _ {\\text {m a s k}} (\\mathcal {F}), \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.415, + 0.469, + 0.46 + ], + "angle": 0, + "content": "where \\(\\mathbf{Center}_t\\in \\mathbb{R}^{n\\times 3}\\), \\(\\mathbf{Class}_t\\in \\mathbb{R}^{n\\times K}\\) and \\(\\mathbf{Mask}_t\\in \\{0,1\\}^{n\\times N}\\) are the predicted centers, classification logits, and the instance masks." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.47, + 0.292, + 0.487 + ], + "angle": 0, + "content": "3.2. Position-aware Designs" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.494, + 0.469, + 0.54 + ], + "angle": 0, + "content": "To effectively support the center regression task and improve the recall of initial instance masks, we propose a series of position-aware designs as follows." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.559, + 0.469, + 0.68 + ], + "angle": 0, + "content": "Learnable Position Query. Unlike previous works [49, 50], we introduce an additional set of position queries \\(\\mathcal{Q}_0^p\\in [0,1]^{n\\times 3}\\). Since the range of points varies significantly among different scenes, the initial position queries are stored in a normalized form as learnable parameters followed by sigmoid function. Basically, we can obtain the absolute positions \\(\\hat{\\mathcal{Q}}_t^p\\in \\mathbb{R}^{n\\times 3}\\) from the normalized position queries \\(\\mathcal{Q}_t^p\\) for a given input scene as" + }, + { + "type": "equation", + "bbox": [ + 0.154, + 0.695, + 0.469, + 0.713 + ], + "angle": 0, + "content": "\\[\n\\hat {\\mathcal {Q}} _ {t} ^ {p} = \\mathcal {Q} _ {t} ^ {p} \\cdot \\left(p _ {\\max } - p _ {\\min }\\right) + p _ {\\min }, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.72, + 0.469, + 0.78 + ], + "angle": 0, + "content": "where the \\(p_{min}, p_{max} \\in \\mathbb{R}^3\\) represent the minimum and maximum coordinates of the input scene, respectively. The resultant \\(\\hat{\\mathcal{Q}}_t^p\\) explicitly represents the positions of the corresponding content queries \\(\\mathcal{Q}_t^c\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.781, + 0.469, + 0.902 + ], + "angle": 0, + "content": "It is notable that the initial position queries are densely spread throughout the 3D space. Also, every query aggregates features from its local region. This design choice makes it easier for the initial queries to capture the objects in a scene with a high recall, as shown in Fig. 3. It overcomes the low-recall issue caused by initial instance masks, and consequently reduces the training complexity of the subsequent layers." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.212 + ], + "angle": 0, + "content": "Relative Position Encoding. Other than the absolute position encoding (e.g., Fourier or sine transformations), we also adopt contextual relative position encoding in crossattention. Inspired by [28], we first calculate the relative positions \\(\\mathbf{r} \\in \\mathbb{R}^{n \\times N \\times 3}\\) between the position queries \\(\\hat{\\mathcal{Q}}_t^p \\in \\mathbb{R}^{n \\times 3}\\) and the global positions \\(\\mathcal{P} \\in \\mathbb{R}^{N \\times 3}\\), and quantize it into discrete integers \\(\\hat{\\mathbf{r}} \\in \\mathbb{Z}^{n \\times N \\times 3}\\) as shown in Fig. 5. It is formulated as" + }, + { + "type": "equation", + "bbox": [ + 0.591, + 0.219, + 0.892, + 0.247 + ], + "angle": 0, + "content": "\\[\n\\mathbf {r} = \\hat {\\mathcal {Q}} _ {t} ^ {p} - \\mathcal {P}, \\quad \\hat {\\mathbf {r}} = \\left\\lfloor \\frac {\\mathbf {r}}{s} \\right\\rfloor + \\frac {L}{2}, \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.249, + 0.892, + 0.293 + ], + "angle": 0, + "content": "where \\( s \\) denotes the quantization size, \\( L \\) denotes the length of position encoding table. We plus \\( \\frac{L}{2} \\) to ensure the discrete relative positions are non-negative." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.294, + 0.892, + 0.355 + ], + "angle": 0, + "content": "Then, we use the discrete relative positions \\(\\hat{\\mathbf{r}}\\) as indices to look up the corresponding position encoding tables \\(\\mathbf{t} \\in \\mathbb{R}^{3 \\times L \\times d}\\), as illustrated in Fig. 5. Formally, the relative position encoding \\(\\mathbf{f}^{pos} \\in \\mathbb{R}^{n \\times N \\times d}\\) is yielded as" + }, + { + "type": "equation", + "bbox": [ + 0.575, + 0.364, + 0.892, + 0.381 + ], + "angle": 0, + "content": "\\[\n\\mathbf {f} ^ {\\text {p o s}} = \\mathbf {t} [ 0, \\hat {\\mathbf {r}} _ {x} ] + \\mathbf {t} [ 1, \\hat {\\mathbf {r}} _ {y} ] + \\mathbf {t} [ 2, \\hat {\\mathbf {r}} _ {z} ], \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.389, + 0.892, + 0.42 + ], + "angle": 0, + "content": "where \\(\\hat{\\mathbf{r}}_x, \\hat{\\mathbf{r}}_y, \\hat{\\mathbf{r}}_z \\in \\mathbb{Z}^{n \\times N}\\) are the discrete relative positions along the \\(x, y\\), and \\(z\\)-axis, respectively." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.421, + 0.892, + 0.465 + ], + "angle": 0, + "content": "Further, the relative position encoding \\(\\mathbf{f}^{pos}\\) performs dot product with the query features \\(\\mathbf{f}^q\\in \\mathbb{R}^{n\\times d}\\) or key features \\(\\mathbf{f}^k\\in \\mathbb{R}^{N\\times d}\\) in the cross-attention, which is formulated as" + }, + { + "type": "equation", + "bbox": [ + 0.575, + 0.474, + 0.892, + 0.495 + ], + "angle": 0, + "content": "\\[\n\\mathbf {p o s} _ {-} \\mathbf {b i a s} _ {i, j} = \\mathbf {f} _ {i, j} ^ {p o s} \\cdot \\mathbf {f} _ {i} ^ {q} + \\mathbf {f} _ {i, j} ^ {p o s} \\cdot \\mathbf {f} _ {j} ^ {k}, \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.503, + 0.892, + 0.548 + ], + "angle": 0, + "content": "where \\( \\text{pos\\_bias} \\in \\mathbb{R}^{n \\times N} \\) is the positional bias. It is then added to the cross-attention weights, followed by the softmax function, as shown in Fig. 4 (b)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.549, + 0.892, + 0.685 + ], + "angle": 0, + "content": "It is worth noting that the RPE offers a greater degree of flexibility and error-insensitivity, compared to mask attention. In essence, RPE can be likened to a soft mask that has the ability to adjust attention weights flexibly, instead of hard masking. Another advantage of RPE is that it integrates semantic information (e.g., object size and class) and thus can harvest local information selectively. This is accomplished by the interaction between the relative positions and the semantic features (i.e., \\(\\mathbf{f}^q\\) and \\(\\mathbf{f}^k\\))." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.703, + 0.892, + 0.857 + ], + "angle": 0, + "content": "Iterative Refinement. Since the content queries in our decoder layers are updated regularly, it is not optimal to maintain frozen position queries throughout the decoding process. Additionally, the initial position queries are static, so it is beneficial to adapt them to the specific input scene in the subsequent layers. To that end, we iteratively refine the position queries based on the content queries. Specifically, as shown in Fig. 4 (b), we leverage an MLP to predict a center offset \\(\\Delta p_{t}\\) from the updated content query \\(Q_{t + 1}^{c}\\). We then add it to the previous position query \\(\\hat{Q}_t^p\\) as" + }, + { + "type": "equation", + "bbox": [ + 0.602, + 0.866, + 0.892, + 0.89 + ], + "angle": 0, + "content": "\\[\n\\Delta p _ {t} = \\mathbf {M L P} _ {\\text {c e n t e r}} \\left(\\mathcal {Q} _ {t + 1} ^ {c}\\right), \\tag {8}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.603, + 0.886, + 0.735, + 0.904 + ], + "angle": 0, + "content": "\\[\n\\hat {\\mathcal {Q}} _ {t + 1} ^ {p} = \\hat {\\mathcal {Q}} _ {t} ^ {p} + \\Delta p _ {t}.\n\\]" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3696" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.168 + ], + "angle": 0, + "content": "Center Matching & Loss. To eliminate the need for duplicate removal methods such as non-maximum suppression (NMS), bipartite matching is adopted during training. Existing works [49, 50] rely on semantic predictions and binary masks to match the ground truths." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.168, + 0.468, + 0.257 + ], + "angle": 0, + "content": "In contrast, to support center regression, we also incorporate center distance in bipartite matching. Since we require the queries to only attend to a local region, it is critical to ensure that they only match with nearby ground-truth objects. To achieve this, we adapt the matching costs formulation as follows" + }, + { + "type": "equation", + "bbox": [ + 0.124, + 0.266, + 0.32, + 0.284 + ], + "angle": 0, + "content": "\\[\n\\mathcal {C} _ {c l s} (k, \\hat {k}) = \\mathrm {C E} (\\mathbf {C l a s s} _ {k}, \\hat {k}),\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.118, + 0.288, + 0.381, + 0.306 + ], + "angle": 0, + "content": "\\[\n\\mathcal {C} _ {d i c e} (k, \\hat {k}) = \\operatorname {D I C E} (\\mathbf {M a s k} _ {k}, \\mathbf {M a s k} _ {\\hat {k}}),\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.122, + 0.31, + 0.468, + 0.335 + ], + "angle": 0, + "content": "\\[\n\\mathcal {C} _ {b c e} (k, \\hat {k}) = \\operatorname {B C E} (\\mathbf {M a s k} _ {k}, \\mathbf {M a s k} _ {\\hat {k}}), \\tag {9}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.103, + 0.331, + 0.425, + 0.392 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {C} _ {\\text {c e n t e r}} (k, \\hat {k}) = \\mathrm {L} _ {1} (\\mathbf {C e n t e r} _ {k}, \\mathbf {C e n t e r} _ {\\hat {k}}), \\\\ \\mathcal {C} (k, \\hat {k}) = \\lambda_ {c l s} \\mathcal {C} _ {c l s} (k, \\hat {k}) + \\lambda_ {d i c e} \\mathcal {C} _ {d i c e} (k, \\hat {k}) \\\\ + \\lambda_ {b c e} \\mathcal {C} _ {b c e} (k, \\hat {k}) + \\lambda_ {c e n t e r} \\mathcal {C} _ {c e n t e r} (k, \\hat {k}), \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.405, + 0.468, + 0.45 + ], + "angle": 0, + "content": "where \\(k\\) and \\(\\hat{k}\\) denotes a predicted and ground-truth instance, respectively, \\(\\mathcal{C} \\in \\mathbb{R}^{n \\times n_{inst}}\\) denotes the matching cost matrix, and \\(\\lambda\\) denotes the cost weights." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.451, + 0.468, + 0.496 + ], + "angle": 0, + "content": "The Hungarian Algorithm is then applied on \\(\\mathcal{C}\\) to yield the one-to-one matching result \\(\\hat{\\sigma} \\in \\mathbb{Z}^n\\), which is followed by the loss function as" + }, + { + "type": "equation", + "bbox": [ + 0.139, + 0.507, + 0.468, + 0.621 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\hat {\\sigma} = \\arg \\min _ {\\sigma : \\sigma_ {i} \\neq \\sigma_ {j}, \\forall i \\neq j} \\sum_ {i = 1} ^ {n} \\mathcal {C} (i, \\sigma_ {i}), \\\\ \\mathcal {L} = \\lambda_ {c l s} \\operatorname {C E} \\left(\\operatorname {C l a s s} _ {i}, \\hat {\\sigma} _ {i}\\right) \\tag {10} \\\\ + \\lambda_ {d i c e} D I C E (\\mathbf {M a s k} _ {i}, \\mathbf {M a s k} _ {\\sigma_ {i}}) \\\\ + \\lambda_ {b c e} \\operatorname {B C E} \\left(\\mathbf {M a s k} _ {i}, \\mathbf {M a s k} _ {\\hat {\\sigma} _ {i}}\\right) \\\\ + \\lambda_ {c e n t e r} L _ {1} \\left(\\text {C e n t e r} _ {i}, \\text {C e n t e r} _ {\\hat {\\sigma} _ {i}}\\right). \\\\ \\end{array}\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.632, + 0.201, + 0.649 + ], + "angle": 0, + "content": "4. Experiment" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.657, + 0.468, + 0.763 + ], + "angle": 0, + "content": "This section first provides an overview of the experimental setup in Sec. 4.1. We then present the 3D instance segmentation results in Sec. 4.2. Additionally, we conduct an extensive ablation study in Sec. 4.3. Furthermore, we showcase the object detection results and visual comparisons in Sections 4.4 and 4.5, respectively. Code and models will be made publicly available." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.772, + 0.277, + 0.789 + ], + "angle": 0, + "content": "4.1. Experimental Setting" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.468, + 0.9 + ], + "angle": 0, + "content": "Network Architecture. For both ScanNetv2 [14] and ScanNet200 [47], we follow previous works [50, 25, 55, 5, 33] to use 5-layer U-Net as the backbone. The initial channel is set to 32. Unless otherwise specified, we use the coordinates and colors as the input features. We use 6 layers of Transformer decoders, where the head number is set to 8 and the hidden and feed-forward dimensions are set" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.258 + ], + "angle": 0, + "content": "to 256 and 1024, respectively. We adopt Fourier absolute position encoding with the temperature set to 10,000. The quantization size for RPE is set to \\(0.1\\mathrm{m}\\), and the length of the RPE table is 48. Unless otherwise specified, we choose [50] as the baseline model, since it has achieved the best performance on ScanNetv2 val set so far. For the S3DIS [1] dataset, following Mask3D [49], we use Res16UNet34C [9] as the backbone and employ 4 decoders to attend to the coarsest four scales, and this is repeated 3 times with the shared parameters. The decoder hidden and feed-forward dimensions are set to 128 and 1024, respectively." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.276, + 0.892, + 0.321 + ], + "angle": 0, + "content": "Datasets. We use the ScanNetv2 [14], ScanNet200 [47] and S3DIS [1] datasets for evaluation. All of them are challenging large-scale indoor scene datasets." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.322, + 0.892, + 0.44 + ], + "angle": 0, + "content": "The ScanNetv2 dataset comprises 1201 scenes for training, and an additional 312 and 100 indoor scenes for validation and testing, respectively. The scenes are captured with RGB-D cameras and annotated with 20 semantic labels, 18 of which are instance classes. The ScanNet200 dataset adopts the same point cloud data, but it offers more diverse annotations, covering 200 classes, 198 of which are instance classes." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.442, + 0.892, + 0.503 + ], + "angle": 0, + "content": "The S3DIS dataset contains 271 rooms in 6 areas of three buildings, and 13 semantic categories are annotated. Following previous works, the scenes in Area 5 are used for validation and the others are for training." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.521, + 0.892, + 0.748 + ], + "angle": 0, + "content": "Implementation Details. We adopt one RTX 3090 GPU for training on ScanNet and ScanNet200, and one A100 GPU on S3DIS. Following previous works, we use AdamW [40] optimizer with the learning rate and weight decay set to 0.0001 and 0.05, respectively. We adopt poly scheduler on ScanNet and ScanNet200, and oncycle scheduler on S3DIS. The batch size is set to 4. For the weights of matching costs and losses, \\((\\lambda_{cls}, \\lambda_{bce}, \\lambda_{dice}, \\lambda_{center})\\) are set to (0.5, 1.0, 1.0, 0.5) on ScanNet and ScanNet200, and (2.0, 5.0, 1.0, 0.5) on S3DIS. The voxel size is set to \\(0.02\\mathrm{m}\\). We limit the points number up to 250,000. Otherwise, we crop the scene by cubic windows iteratively until the point number is lower than the limit. During inference, we select the top 100 instances with the highest scores and set the minimum points number per instance to 100." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.757, + 0.771, + 0.773 + ], + "angle": 0, + "content": "4.2. Instance Segmentation Results" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.892, + 0.901 + ], + "angle": 0, + "content": "ScanNetv2. We present the results of instance segmentation on both the ScanNetv2 test and val sets in Tables 1 and 2, respectively. Our method achieves a considerable increase in mAP compared to previous works, suggesting a superior ability to capture fine-grained details and produce high-quality instance segmentation. While Mask3D [49] slightly outperforms our model in terms of \\(\\mathrm{mAP}_{50}\\), it is worth noting that this is potentially due to their use of a" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3697" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.08, + 0.09, + 0.897, + 0.319 + ], + "angle": 0, + "content": "
MethodmAP\\( \\mathrm{mAP}_{50} \\)bathbedbkshfcabinetchaircountercurtaindeskdoorotherpicturefridges. cur.sinksofatabletoiletwind.
3D-BoNet [2]25.348.851.932.425.113.734.53.141.96.916.213.15.220.233.814.730.130.365.117.8
MTML [26]28.240.257.738.018.210.743.00.142.25.717.916.27.022.951.116.149.131.365.016.2
GICN [38]34.163.858.037.134.419.846.95.256.49.321.221.212.734.753.720.652.532.972.924.1
3D-MPA [17]35.561.145.748.429.927.759.14.733.221.221.727.819.341.341.019.557.435.284.921.3
Dyco3D [20]39.564.164.251.844.725.966.65.025.116.623.136.223.233.153.522.958.743.885.031.7
PE [69]39.664.566.746.744.624.362.42.257.710.621.934.023.948.747.522.554.135.081.827.3
PointGroup [25]40.763.663.949.641.524.364.52.157.011.421.135.921.742.866.625.656.234.186.029.1
HAIS [5]45.769.970.456.145.736.467.34.654.719.430.842.628.845.471.126.256.343.488.934.4
OccuSeg [19]48.667.280.253.642.836.970.220.533.130.137.947.432.743.786.248.560.139.484.627.3
SoftGroup [55]50.476.166.757.937.238.169.47.267.730.338.753.131.958.275.431.864.349.290.738.8
SSTNet [33]50.669.873.854.949.731.669.317.837.719.833.046.357.651.585.749.463.745.794.329.0
SPFormer [50]54.977.074.564.048.439.573.931.156.633.546.849.255.547.874.743.671.254.089.334.3
Mask3D* [49]56.678.092.659.740.842.073.723.959.838.645.854.956.871.660.148.064.657.592.236.4
Ours57.877.477.864.952.044.976.125.358.439.153.047.261.749.979.547.374.554.896.037.4
\\( Ours^‡ \\)59.678.688.972.144.846.076.825.155.840.850.453.961.661.885.848.268.455.193.145.0
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.322, + 0.892, + 0.351 + ], + "angle": 0, + "content": "Table 1. 3D instance segmentation results on ScanNet test set. * denotes using Res16UNet34C (twice as many parameters as ours) as the backbone. ‡ denotes using surface normal. Methods published before the submission deadline (03/08/2023) are listed." + }, + { + "type": "table", + "bbox": [ + 0.081, + 0.373, + 0.467, + 0.615 + ], + "angle": 0, + "content": "
MethodmAP\\( \\mathrm{mAP}_{50} \\)
GSPN [67]19.337.8
MTML [26]20.340.2
3D-MPA [17]35.559.1
Dyco3D [20]35.457.6
PointGroup [25]34.856.7
MaskGroup [75]42.063.3
HAIS [5]43.564.1
OccuSeg [19]44.260.7
SoftGroup [55]46.067.6
SSTNet [33]49.464.3
SPFormer [50]56.373.9
Mask3D* [49]55.273.7
Ours58.475.9
\\( Ours^‡ \\)59.976.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.63, + 0.468, + 0.672 + ], + "angle": 0, + "content": "Table 2. 3D instance segmentation results on ScanNet val set. * denotes using Res16UNet34C (twice as many parameters as ours) as the backbone. ‡ denotes using surface normal." + }, + { + "type": "table", + "bbox": [ + 0.08, + 0.685, + 0.462, + 0.763 + ], + "angle": 0, + "content": "
MethodmAP\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
\\( SPFormer^† \\)[50]25.233.839.6
\\( Mask3D* \\)[49]27.437.042.3
Ours29.238.243.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.771, + 0.468, + 0.799 + ], + "angle": 0, + "content": "Table 3. 3D instance segmentation results on ScanNet200 val set. \\( {}^{ \\dagger } \\) denotes reproduced results. * denotes using Res16UNet34C." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.825, + 0.468, + 0.9 + ], + "angle": 0, + "content": "stronger backbone (i.e., Res16UNet34C with twice as many parameters as ours) and DBSCAN post-processing. Despite this, our approach produces significantly better performance on the ScanNetv2 val set than Mask3D, as seen in Table 2." + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.373, + 0.889, + 0.51 + ], + "angle": 0, + "content": "
Method\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
PointGroup [25]57.8-
MaskGroup [75]65.0-
SoftGroup [55]66.1-
SSTNet [33]59.3-
SPFormer [50]66.8-
Mask3D [49]68.475.2
Ours69.175.7
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.52, + 0.853, + 0.535 + ], + "angle": 0, + "content": "Table 4. 3D instance segmentation results on S3DIS Area5." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.559, + 0.892, + 0.681 + ], + "angle": 0, + "content": "ScanNet200. Table 3 presents our comparison with previous state-of-the-art methods on the val set of ScanNet200. Our method achieves a significant improvement in comparison to the other methods. Consistent conclusion is also seen on this challenging dataset. It is important to note that previous works employ mask attention, while our approach does not. This verifies the success of our auxiliary center regression task in replacing mask attention." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.699, + 0.892, + 0.745 + ], + "angle": 0, + "content": "S3DIS. As shown in Table 4, our method is evaluated on S3DIS Area5. Our approach outperforms previous works. This consistently shows the superiority of our method." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.753, + 0.655, + 0.77 + ], + "angle": 0, + "content": "4.3. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.777, + 0.892, + 0.807 + ], + "angle": 0, + "content": "We conduct an extensive ablation study to verify each component of our method as follows." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Learnable Position Query. The position query aims to provide an explicit center representation to the content query counterpart. Making it learnable intends to learn an optimal initial spatial distribution. We notice that some previous works [49, 42] adopt non-parametric initial queries," + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3698" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.092, + 0.351, + 0.21 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.285, + 0.209, + 0.304, + 0.22 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "image", + "bbox": [ + 0.352, + 0.092, + 0.485, + 0.21 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.487, + 0.092, + 0.619, + 0.21 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.621, + 0.092, + 0.753, + 0.21 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.755, + 0.092, + 0.887, + 0.21 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.687, + 0.209, + 0.706, + 0.22 + ], + "angle": 0, + "content": "(b)" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.225, + 0.894, + 0.296 + ], + "angle": 0, + "content": "Figure 6. Spatial distribution of ground truths that are matched to the same query at different training iterations. (a): Baseline. (b): Ours. We randomly select 10 object queries and record their matched ground-truth instances in the early training. The three scatter plots for each method represent the center XYZ coordinates of their matched ground-truth instances at different training iterations (the scatter points for a query correspond to different training iterations). More visualization details are given in supplementary material. Our method manifests strong positional matching consistency among different training iterations." + }, + { + "type": "table", + "bbox": [ + 0.08, + 0.317, + 0.468, + 0.409 + ], + "angle": 0, + "content": "
PositionContentmAP\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
FPSzero57.374.984.2
FPSlearnable57.175.083.4
learnablelearnable58.175.484.3
learnablezero58.475.984.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.416, + 0.47, + 0.445 + ], + "angle": 0, + "content": "Table 5. Ablation study on different initializations for position and content queries." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.457, + 0.469, + 0.549 + ], + "angle": 0, + "content": "
Position EncodingmAP\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
No PE0.00.00.0
Fourier APE57.776.083.8
Content-conditioned APE58.075.784.3
RPE58.475.984.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.107, + 0.557, + 0.438, + 0.572 + ], + "angle": 0, + "content": "Table 6. Ablation study on different position encodings." + }, + { + "type": "table", + "bbox": [ + 0.081, + 0.585, + 0.468, + 0.681 + ], + "angle": 0, + "content": "
IDiter. refinecenter matchcenter lossmAP\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
1✓✓57.575.384.0
2✓✓56.774.884.1
3✓✓56.874.684.5
4✓56.474.783.7
5✓✓✓58.475.984.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.688, + 0.469, + 0.716 + ], + "angle": 0, + "content": "Table 7. Ablation study on iterative refinement and center matching & loss." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.734, + 0.469, + 0.84 + ], + "angle": 0, + "content": "where Furthest Point Sampling (FPS) is used to sample a number of points and transform them into position encodings via Fourier transformation followed by an MLP. We make comparisons in Table 5. The results show that learnable position query and zero-initialized content query perform best. A potential reason why 'FPS' lags behind 'learnable' is that the latter learns an optimal spatial distribution." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Moreover, to show the pattern of the learnable position query, we visualize the spatial distribution of center coordinates of the matched ground truths for a query in Fig. 6. It shows that each query consistently attends to a local region." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.32, + 0.892, + 0.516 + ], + "angle": 0, + "content": "Relative Position Encoding. We compare various position encodings that are employed in previous works [49, 41], such as Fourier Absolute Position Encoding (APE) and the content query-conditioned APE. Specifically, the latter uses an MLP to project the content query into a \\(d\\)-dim diagonal matrix, which then transforms the original absolute position encoding into a new one. It incorporates semantic information into the position encoding but does not consider relative relation. As shown in Table 6, RPE outperforms the others, which implies that both semantic information and relative relation are beneficial. Also, we notice that if we do not apply any position encoding, the training corrupts. This shows that positional prior is crucial in our framework." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.534, + 0.892, + 0.609 + ], + "angle": 0, + "content": "Iterative Refinement. We remove the iterative refinement and freeze the position query in all decoder layers, and we find that it causes a performance drop of \\(0.9\\%\\) mAP as shown in the first row of Table 7. This verifies the effectiveness of iterative refinement." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.628, + 0.892, + 0.793 + ], + "angle": 0, + "content": "Center Matching & Loss. Moreover, to manifest the importance of center matching and center loss, we also conduct ablation studies in Table 7. We first remove the center matching and keep the center loss in the second row of the table, and we find that the performance drops by \\(1.7\\%\\) mAP. Then we keep the center matching and remove the center loss. The performance also decreases by \\(1.6\\%\\) mAP as shown in the 3-rd row. When both are absent, we observe an even larger performance drop \\((2.0\\% \\mathrm{mAP})\\) in the 4-th row. The results reveal that both center matching and loss are important to our framework." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.802, + 0.727, + 0.818 + ], + "angle": 0, + "content": "4.4. Object Detection Results" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "The instance predictions of instance segmentation can be easily transformed into bounding box predictions, by obtaining the minimum and maximum coordinates of the masked instances. We empirically find that the generated object detection results from the instance predictions work" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3699" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.088, + 0.088, + 0.887, + 0.51 + ], + "angle": 0, + "content": null + }, + { + "type": "table", + "bbox": [ + 0.107, + 0.517, + 0.436, + 0.713 + ], + "angle": 0, + "content": "
Methodtaskbox mAP50box mAP25
VoteNet [44]det33.558.6
HGNet [4]det34.461.3
MLCVNet [65]det41.464.5
GSDN [18]det34.862.8
H3DNet [72]det48.167.2
3DETR [42]det47.065.0
Group-free [39]det52.869.1
RBGNet [57]det55.270.6
HyperDet3D [74]det57.270.9
FCAF3D [48]det57.371.5
CAGroup3D [56]det61.375.1
3D-MPA [17]inst49.264.2
Mask3D [49]inst56.270.2
Oursinst63.973.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.717, + 0.47, + 0.76 + ], + "angle": 0, + "content": "Table 8. 3D object detection results on ScanNetv2. For methods designed for the instance segmentation task, the bounding boxes are generated by the instance mask predictions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.772, + 0.47, + 0.834 + ], + "angle": 0, + "content": "significantly better than previous methods tailored for 3D object detection in terms of \\(\\mathrm{mAP}_{50}\\), as shown in Table 8. This finding also shows that our approach outputs high-quality instance segmentation results with fewer artifacts." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.846, + 0.262, + 0.863 + ], + "angle": 0, + "content": "4.5. Visual Comparison" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.871, + 0.47, + 0.903 + ], + "angle": 0, + "content": "We visually compare our approach with previous state-of-the-art methods in Fig. 7. More examples are given in" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.52, + 0.893, + 0.581 + ], + "angle": 0, + "content": "the supplementary material. The visualizations demonstrate that our method tends to correctly recognize the classes of the instances. It implies that our approach is able to generate more high-quality instance segmentation results." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.598, + 0.619, + 0.614 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.625, + 0.893, + 0.806 + ], + "angle": 0, + "content": "In this work, we have presented a mask-attention-free transformer for the 3D instance segmentation task. We first observe the issue of low-recall of the initial masks in existing works. It adds training difficulty and slows down convergence. We thus avoid using mask attention and instead propose an auxiliary center regression task to guide the cross-attention. To fit center regression, we develop a series of designs. A dense distribution of position queries is learned to yield a higher recall of the perceived instances. Also, relative position encoding and iterative refinement are designed to further boost the performance. Each component is verified to be effective." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.818, + 0.667, + 0.835 + ], + "angle": 0, + "content": "Acknowledgements" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.841, + 0.893, + 0.901 + ], + "angle": 0, + "content": "This work was supported in part by the Research Grants Council under the Areas of Excellence scheme grant AoE/E-601/22-R and Shenzhen Science and Technology Program KQTD20210811090149095." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3700" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.47, + 0.169 + ], + "angle": 0, + "content": "[1] Iro Armeni, Ozan Sener, Amir R. Zamir, Helen Jiang, Ioannis Brilakis, Martin Fischer, and Silvio Savarese. 3d semantic parsing of large-scale indoor spaces. In CVPR, 2016. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.173, + 0.468, + 0.227 + ], + "angle": 0, + "content": "[2] Yang Bo, Wang Jianan, Clark Ronald, Hu Qingyong, Wang Sen, Markham Andrew, and Trigoni Niki. Learning object bounding boxes for 3d instance segmentation on point clouds. In NeurIPS, pages 6737-6746, 2019. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.231, + 0.468, + 0.271 + ], + "angle": 0, + "content": "[3] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In ECCV, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.274, + 0.468, + 0.315 + ], + "angle": 0, + "content": "[4] Jintai Chen, Biwen Lei, Qingyu Song, Haochao Ying, Danny Z Chen, and Jian Wu. A hierarchical graph network for 3d object detection on point clouds. In CVPR, 2020. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.317, + 0.468, + 0.37 + ], + "angle": 0, + "content": "[5] Shaoyu Chen, Jiemin Fang, Qian Zhang, Wenyu Liu, and Xinggang Wang. Hierarchical aggregation for 3d instance segmentation. In ICCV, pages 15467-15476, 2021. 1, 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.374, + 0.468, + 0.413 + ], + "angle": 0, + "content": "[6] Yukang Chen, Yanwei Li, Xiangyu Zhang, Jian Sun, and Jiaya Jia. Focal sparse convolutional networks for 3d object detection. In CVPR, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.417, + 0.468, + 0.47 + ], + "angle": 0, + "content": "[7] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.474, + 0.468, + 0.514 + ], + "angle": 0, + "content": "[8] Bowen Cheng, Alex Schwing, and Alexander Kirillov. Per-pixel classification is not all you need for semantic segmentation. NeurIPS, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.517, + 0.468, + 0.557 + ], + "angle": 0, + "content": "[9] Christopher Choy, JunYoung Gwak, and Silvio Savarese. 4d spatio-temporal convnets: Minkowski convolutional neural networks. In CVPR, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.561, + 0.468, + 0.613 + ], + "angle": 0, + "content": "[10] Ruihang Chu, Yukang Chen, Tao Kong, Lu Qi, and Lei Li. Icm-3d: Instantiated category modeling for 3d instance segmentation. IEEE Robotics and Automation Letters, 7(1):57-64, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.618, + 0.468, + 0.671 + ], + "angle": 0, + "content": "[11] Ruihang Chu, Zhengzhe Liu, Xiaqing Ye, Xiao Tan, Xiaojuan Qi, Chi-Wing Fu, and Jiaya Jia. Command-driven articulated object understanding and manipulation. In CVPR, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.675, + 0.468, + 0.728 + ], + "angle": 0, + "content": "[12] Ruihang Chu, Xiaqing Ye, Zhengzhe Liu, Xiao Tan, Xiaojuan Qi, Chi-Wing Fu, and Jiaya Jia. Twist: Two-way inter-label self-training for semi-supervised 3d instance segmentation. In CVPR, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.732, + 0.468, + 0.785 + ], + "angle": 0, + "content": "[13] Xiangxiang Chu, Zhi Tian, Yuqing Wang, Bo Zhang, Haibing Ren, Xiaolin Wei, Huaxia Xia, and Chunhua Shen. Twins: Revisiting the design of spatial attention in vision transformers. arXiv:2104.13840, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.789, + 0.468, + 0.842 + ], + "angle": 0, + "content": "[14] Angela Dai, Angel X. Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In CVPR, 2017. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.468, + 0.9 + ], + "angle": 0, + "content": "[15] Xiaoyi Dong, Jianmin Bao, Dongdong Chen, Weiming Zhang, Nenghai Yu, Lu Yuan, Dong Chen, and Baining Guo. Cswin transformer: A general vision transformer backbone with cross-shaped windows. arXiv:2107.00652, 2021. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.47, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.175 + ], + "angle": 0, + "content": "[16] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. ICLR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.178, + 0.892, + 0.232 + ], + "angle": 0, + "content": "[17] Francis Engelmann, Martin Bokeloh, Alireza Fathi, Bastian Leibe, and Matthias Nießner. 3d-mpa: Multi-proposal aggregation for 3d semantic instance segmentation. In CVPR, pages 9031-9040, 2020. 2, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.234, + 0.892, + 0.274 + ], + "angle": 0, + "content": "[18] JunYoung Gwak, Christopher Choy, and Silvio Savarese. Generative sparse detection networks for 3d single-shot object detection. In ECCV, 2020. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.277, + 0.892, + 0.317 + ], + "angle": 0, + "content": "[19] Lei Han, Tian Zheng, Lan Xu, and Lu Fang. Occuseg: Occupancy-aware 3d instance segmentation. In CVPR, pages 2940-2949, 2020. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.32, + 0.892, + 0.373 + ], + "angle": 0, + "content": "[20] Tong He, Chunhua Shen, and Anton van den Hengel. Dyco3d: Robust instance segmentation of 3d point clouds through dynamic convolution. In CVPR, pages 354-363, 2021. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.376, + 0.892, + 0.416 + ], + "angle": 0, + "content": "[21] Ji Hou, Angela Dai, and Matthias Nießner. 3d-sis: 3d semantic instance segmentation of rgb-d scans. In CVPR, pages 4421-4430, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.419, + 0.892, + 0.46 + ], + "angle": 0, + "content": "[22] Ding Jia, Yuhui Yuan, Haodi He, Xiaopei Wu, Haojun Yu, Weihong Lin, Lei Sun, Chao Zhang, and Han Hu. Detrs with hybrid matching. arXiv preprint, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.462, + 0.892, + 0.503 + ], + "angle": 0, + "content": "[23] Haiyong Jiang, Feilong Yan, Jianfei Cai, Jianmin Zheng, and Jun Xiao. End-to-end 3d point cloud instance segmentation without detection. In CVPR, pages 12796-12805, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.505, + 0.892, + 0.559 + ], + "angle": 0, + "content": "[24] Li Jiang, Shaoshuai Shi, Zhuotao Tian, Xin Lai, Shu Liu, Chi-Wing Fu, and Jiaya Jia. Guided point contrastive learning for semi-supervised point cloud semantic segmentation. In ICCV, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.562, + 0.892, + 0.615 + ], + "angle": 0, + "content": "[25] Li Jiang, Hengshuang Zhao, Shaoshuai Shi, Shu Liu, ChiWing Fu, and Jiaya Jia. Pointgroup: Dual-set point grouping for 3d instance segmentation. In CVPR, pages 4867-4876, 2020. 1, 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.618, + 0.892, + 0.658 + ], + "angle": 0, + "content": "[26] Jean Lahoud, Bernard Ghanem, Marc Pollefeys, and Martin R Oswald. 3d instance segmentation via multi-task metric learning. In ICCV, pages 9256-9266, 2019. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.661, + 0.892, + 0.701 + ], + "angle": 0, + "content": "[27] Xin Lai, Yukang Chen, Fanbin Lu, Jianhui Liu, and Jiaya Jia. Spherical transformer for lidar-based 3d recognition. In CVPR, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.704, + 0.892, + 0.757 + ], + "angle": 0, + "content": "[28] Xin Lai, Jianhui Liu, Li Jiang, Liwei Wang, Hengshuang Zhao, Shu Liu, Xiaojuan Qi, and Jiaya Jia. Stratified transformer for 3d point cloud segmentation. In CVPR, 2022. 2, 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.76, + 0.892, + 0.801 + ], + "angle": 0, + "content": "[29] Feng Li, Hao Zhang, Shilong Liu, Jian Guo, Lionel M Ni, and Lei Zhang. Dn-detr: Accelerate detr training by introducing query denoising. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.804, + 0.892, + 0.858 + ], + "angle": 0, + "content": "[30] Feng Li, Hao Zhang, Shilong Liu, Lei Zhang, Lionel M Ni, Heung-Yeung Shum, et al. Mask dino: Towards a unified transformer-based framework for object detection and segmentation. arXiv preprint, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.86, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[31] Yanwei Li, Yilun Chen, Xiaojuan Qi, Zeming Li, Jian Sun, and Jiaya Jia. Unifying voxel-based representation with transformer for 3d object detection. NeurIPS, 2022. 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.514, + 0.957 + ], + "angle": 0, + "content": "3701" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.133 + ], + "angle": 0, + "content": "[32] Yanwei Li, Xiaojuan Qi, Yukang Chen, Liwei Wang, Zeming Li, Jian Sun, and Jiaya Jia. Voxel field fusion for 3d object detection. In CVPR, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.134, + 0.47, + 0.176 + ], + "angle": 0, + "content": "[33] Zhihao Liang, Zhihao Li, Songcen Xu, Mingkui Tan, and Kui Jia. Instance segmentation in 3d scenes using semantic superpoint tree networks. In ICCV, 2021. 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.177, + 0.469, + 0.232 + ], + "angle": 0, + "content": "[34] Jiahui Liu, Chirui Chang, Jianhui Liu, Xiaoyang Wu, Lan Ma, and Xiaojuan Qi. Mars3d: A plug-and-play motion-aware model for semantic segmentation on multi-scan 3d point clouds. In CVPR, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.233, + 0.469, + 0.273 + ], + "angle": 0, + "content": "[35] Jianhui Liu, Yukang Chen, Xiaqing Ye, and Xiaojuan Qi. Prior-free category-level pose estimation with implicit space transformation. arXiv preprint arXiv:2303.13479, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.274, + 0.469, + 0.315 + ], + "angle": 0, + "content": "[36] Jianhui Liu, Yukang Chen, Xiaqing Ye, Zhuotao Tian, Xiao Tan, and Xiaojuan Qi. Spatial pruned sparse convolution for efficient 3d object detection. NeurIPS, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.316, + 0.469, + 0.357 + ], + "angle": 0, + "content": "[37] Shilong Liu, Feng Li, Hao Zhang, Xiao Yang, Xianbiao Qi, Hang Su, Jun Zhu, and Lei Zhang. Dab-detr: Dynamic anchor boxes are better queries for detr. In ICLR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.358, + 0.469, + 0.399 + ], + "angle": 0, + "content": "[38] Shih-Hung Liu, Shang-Yi Yu, Shao-Chi Wu, Hwann-Tzong Chen, and Tyng-Luh Liu. Learning gaussian instance segmentation in point clouds. arXiv preprint, 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.4, + 0.469, + 0.439 + ], + "angle": 0, + "content": "[39] Ze Liu, Zheng Zhang, Yue Cao, Han Hu, and Xin Tong. Group-free 3d object detection via transformers. In ICCV, 2021. 3, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.441, + 0.469, + 0.469 + ], + "angle": 0, + "content": "[40] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. arXiv:1711.05101, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.47, + 0.469, + 0.523 + ], + "angle": 0, + "content": "[41] Depu Meng, Xiaokang Chen, Zejia Fan, Gang Zeng, Houqiang Li, Yuhui Yuan, Lei Sun, and Jingdong Wang. Conditional detr for fast training convergence. In ICCV, 2021. 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.525, + 0.469, + 0.565 + ], + "angle": 0, + "content": "[42] Ishan Misra, Rohit Girdhar, and Armand Joulin. An end-to-end transformer model for 3d object detection. In ICCV, 2021. 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.567, + 0.469, + 0.594 + ], + "angle": 0, + "content": "[43] Chunghyun Park, Yoonwoo Jeong, Minsu Cho, and Jaesik Park. Fast point transformer. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.595, + 0.469, + 0.636 + ], + "angle": 0, + "content": "[44] Charles R Qi, Or Litany, Kaiming He, and Leonidas J Guibas. Deep hough voting for 3d object detection in point clouds. In ICCV, 2019. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.637, + 0.469, + 0.678 + ], + "angle": 0, + "content": "[45] Charles R Qi, Hao Su, Kaichun Mo, and Leonidas J Guibas. Pointnet: Deep learning on point sets for 3d classification and segmentation. In CVPR, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.679, + 0.469, + 0.719 + ], + "angle": 0, + "content": "[46] Charles Ruizhongtai Qi, Li Yi, Hao Su, and Leonidas J Guibas. Pointnet++: Deep hierarchical feature learning on point sets in a metric space. NeurIPS, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.721, + 0.469, + 0.761 + ], + "angle": 0, + "content": "[47] David Rozenberszki, Or Litany, and Angela Dai. Language-grounded indoor 3d semantic segmentation in the wild. In ECCV, 2022. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.762, + 0.469, + 0.802 + ], + "angle": 0, + "content": "[48] Danila Rukhovich, Anna Vorontsova, and Anton Konushin. Fcaf3d: fully convolutional anchor-free 3d object detection. In ECCV, 2022. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.804, + 0.469, + 0.857 + ], + "angle": 0, + "content": "[49] Jonas Schult, Francis Engelmann, Alexander Hermans, Or Litany, Siyu Tang, and Bastian Leibe. Mask3d for 3d semantic instance segmentation. ICRA, 2023. 1, 2, 3, 4, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.859, + 0.469, + 0.9 + ], + "angle": 0, + "content": "[50] Jiahao Sun, Chunmei Qing, Junpeng Tan, and Xiangmin Xu. Superpoint transformer for 3d scene instance segmentation. AAAI, 2023. 1, 2, 3, 4, 5, 6" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.092, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[51] Shuyang Sun, Xiaoyu Yue, Song Bai, and Philip Torr. Visual parser: Representing part-whole hierarchies with transformers. arXiv:2107.05790, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[52] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Herve Jegou. Training data-efficient image transformers & distillation through attention. In ICML, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.192, + 0.892, + 0.233 + ], + "angle": 0, + "content": "[53] Hugo Touvron, Matthieu Cord, Alexandre Sablayrolles, Gabriel Synnaeve, and Hervé Jégou. Going deeper with image transformers. arXiv:2103.17239, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.235, + 0.892, + 0.276 + ], + "angle": 0, + "content": "[54] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In NeurIPS, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.278, + 0.892, + 0.319 + ], + "angle": 0, + "content": "[55] Thang Vu, Kookhoi Kim, Tung M Luu, Thanh Nguyen, and Chang D Yoo. Softgroup for 3d instance segmentation on point clouds. In CVPR, 2022. 1, 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.321, + 0.892, + 0.375 + ], + "angle": 0, + "content": "[56] Haiyang Wang, Lihe Ding, Shaocong Dong, Shaoshuai Shi, Aoxue Li, Jianan Li, Zhenguo Li, and Liwei Wang. Cagroup3d: Class-aware grouping for 3d object detection on point clouds. In NeurIPS, 2022. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.377, + 0.892, + 0.431 + ], + "angle": 0, + "content": "[57] Haiyang Wang, Shaoshuai Shi, Ze Yang, Rongyao Fang, Qi Qian, Hongsheng Li, Bernt Schiele, and Liwei Wang. Rbgnet: Ray-based grouping for 3d object detection. In CVPR, 2022. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.433, + 0.892, + 0.488 + ], + "angle": 0, + "content": "[58] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pvtv2: Improved baselines with pyramid vision transformer. arXiv:2106.13797, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.49, + 0.892, + 0.544 + ], + "angle": 0, + "content": "[59] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In ICCV, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.546, + 0.892, + 0.6 + ], + "angle": 0, + "content": "[60] Weiyue Wang, Ronald Yu, Qiangui Huang, and Ulrich Neumann. Sgpn: Similarity group proposal network for 3d point cloud instance segmentation. In CVPR, pages 2569-2578, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.603, + 0.892, + 0.644 + ], + "angle": 0, + "content": "[61] Xinlong Wang, Shu Liu, Xiaoyong Shen, Chunhua Shen, and Jiaya Jia. Associatively segmenting instances and semantics in point clouds. In CVPR, pages 4096-4105, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.646, + 0.892, + 0.686 + ], + "angle": 0, + "content": "[62] Yingming Wang, Xiangyu Zhang, Tong Yang, and Jian Sun. Anchor detr: Query design for transformer-based detector. In AAAI, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.688, + 0.892, + 0.729 + ], + "angle": 0, + "content": "[63] Wenxuan Wu, Qi Shan, and Li Fuxin. Pointconvformer: Re-venge of the point-based convolution. arXiv preprint, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.731, + 0.892, + 0.772 + ], + "angle": 0, + "content": "[64] Xiaoyang Wu, Yixing Lao, Li Jiang, Xihui Liu, and Hengshuang Zhao. Point transformer v2: Grouped vector attention and partition-based pooling. NeurIPS, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.774, + 0.892, + 0.815 + ], + "angle": 0, + "content": "[65] Qian Xie, Yu-Kun Lai, Jing Wu, Zhoutao Wang, Yiming Zhang, Kai Xu, and Jun Wang. Mlcvnet: Multi-level context votenet for 3d object detection. In CVPR, 2020. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.817, + 0.892, + 0.87 + ], + "angle": 0, + "content": "[66] Jianwei Yang, Chunyuan Li, Pengchuan Zhang, Xiyang Dai, Bin Xiao, Lu Yuan, and Jianfeng Gao. Focal self-attention for local-global interactions in vision transformers. In NeurIPS, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.873, + 0.892, + 0.902 + ], + "angle": 0, + "content": "[67] Li Yi, Wang Zhao, He Wang, Minhyuk Sung, and Leonidas J Guibas. Gspn: Generative shape proposal network for 3d" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.092, + 0.892, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "3702" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.469, + 0.12 + ], + "angle": 0, + "content": "instance segmentation in point cloud. In CVPR, pages 3947-3956, 2019. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.469, + 0.162 + ], + "angle": 0, + "content": "[68] Qihang Yu, Huiyu Wang, Siyuan Qiao, Maxwell Collins, Yukun Zhu, Hartwig Adam, Alan Yuille, and Liang-Chieh Chen. k-means mask transformer. In ECCV, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.165, + 0.469, + 0.205 + ], + "angle": 0, + "content": "[69] Biao Zhang and Peter Wonka. Point cloud instance segmentation using probabilistic embeddings. In CVPR, pages 8883-8892, 2021. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.208, + 0.469, + 0.248 + ], + "angle": 0, + "content": "[70] Gongjie Zhang, Zhipeng Luo, Yingchen Yu, Kaiwen Cui, and Shijian Lu. Accelerating detr convergence via semantic-aligned matching. In CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.251, + 0.469, + 0.304 + ], + "angle": 0, + "content": "[71] Hao Zhang, Feng Li, Shilong Liu, Lei Zhang, Hang Su, Jun Zhu, Lionel Ni, and Harry Shum. Dino: Detr with improved denoising anchor boxes for end-to-end object detection. In ICLR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.307, + 0.469, + 0.347 + ], + "angle": 0, + "content": "[72] Zaiwei Zhang, Bo Sun, Haitao Yang, and Qixing Huang. H3dnet: 3d object detection using hybrid geometric primitives. In ECCV, 2020. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.35, + 0.469, + 0.376 + ], + "angle": 0, + "content": "[73] Hengshuang Zhao, Li Jiang, Jiaya Jia, Philip HS Torr, and Vladlen Koltun. Point transformer. In ICCV, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.379, + 0.469, + 0.419 + ], + "angle": 0, + "content": "[74] Yu Zheng, Yueqi Duan, Jiwen Lu, Jie Zhou, and Qi Tian. Hyperdet3d: Learning a scene-conditioned 3d object detector. In CVPR, 2022. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.422, + 0.469, + 0.462 + ], + "angle": 0, + "content": "[75] Min Zhong, Xinghao Chen, Xiaokang Chen, Gang Zeng, and Yunhe Wang. Maskgroup: Hierarchical point grouping and masking for 3d instance segmentation. In ICME, 2022. 1, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.465, + 0.469, + 0.505 + ], + "angle": 0, + "content": "[76] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable detr: Deformable transformers for end-to-end object detection. In ICLR, 2020. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.505 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "3703" + } + ] +] \ No newline at end of file diff --git a/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/2a13e96b-8070-4a45-a596-f26ce5eefa9a_origin.pdf b/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/2a13e96b-8070-4a45-a596-f26ce5eefa9a_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..e25b09d72aec0a13d6f0a08c824df7f339134685 --- /dev/null +++ b/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/2a13e96b-8070-4a45-a596-f26ce5eefa9a_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:7548274d32193385d86e9b5289f8a95f598bbd64d33a8767b4ca485046051d31 +size 7747240 diff --git a/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/full.md b/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/full.md new file mode 100644 index 0000000000000000000000000000000000000000..1b8671a9880e53bf5441b63e37303b3b5cdda8b5 --- /dev/null +++ b/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/full.md @@ -0,0 +1,362 @@ +# Mask-Attention-Free Transformer for 3D Instance Segmentation + +Xin Lai1 Yuhui Yuan3 Ruihang Chu1 +1The Chinese University of Hong Kong + +Yukang Chen $^{1}$ Han Hu $^{3}$ Jiaya Jia $^{1,2*}$ $^{2}$ SmartMore ${ }^{3}$ Microsoft Research Asia + +# Abstract + +Recently, transformer-based methods have dominated 3D instance segmentation, where mask attention is commonly involved. Specifically, object queries are guided by the initial instance masks in the first cross-attention, and then iteratively refine themselves in a similar manner. However, we observe that the mask-attention pipeline usually leads to slow convergence due to low-recall initial instance masks. Therefore, we abandon the mask attention design and resort to an auxiliary center regression task instead. Through center regression, we effectively overcome the low-recall issue and perform cross-attention by imposing positional prior. To reach this goal, we develop a series of position-aware designs. First, we learn a spatial distribution of 3D locations as the initial position queries. They spread over the 3D space densely, and thus can easily capture the objects in a scene with a high recall. Moreover, we present relative position encoding for the cross-attention and iterative refinement for more accurate position queries. Experiments show that our approach converges $4\times$ faster than existing work, sets a new state of the art on ScanNetv2 3D instance segmentation benchmark, and also demonstrates superior performance across various datasets. Code and models are available at https://github.com/dvlab-research/Mask-Attention-Free-Transformer. + +# 1. Introduction + +Nowadays 3D point clouds can be conveniently collected. They have benefited various applications, such as autonomous driving, robotics, and augmented reality. As a fundamental task, 3D instance segmentation also poses great challenges simultaneously, such as geometric occlusion and semantic ambiguity. + +Many works have been proposed to solve the 3D instance segmentation task. Grouping-based methods [25, 55, 5, 75] rely on heuristic clustering algorithms such as DBSCAN or Breadth-First Search (BFS) to generate instance proposals. They thus require sophisticated hyper-parameters + +![](images/618eb093ee1d77ccda03fa2bf3a161b9c7c9d4c63897dad16e183746fe163f50.jpg) +Figure 1. Validation curve of the baseline and ours on ScanNetv2 val set. With only 128-epoch training, ours outperforms the baseline trained with 512 epochs. + +tuning and are prone to wrongly segment instances that are close to each other. Recently, transformer-based methods [49, 50] develop a fully end-to-end pipeline. With transformer decoder layers, a fixed number of object queries attend to global features iteratively and directly output instance predictions. It requires no post-processing for duplicate removal such as NMS, since it adopts one-to-one bipartite matching during training. Moreover, it employs mask attention, which uses the instance masks predicted in the last layer to guide the cross-attention. + +However, we point out that current transformer-based methods suffer from the issue of slow convergence. As shown in Fig. 1, the baseline model manifests slow convergence and lags behind our method by a large margin, particularly in the early stages of training. We dive further and find that the issue is potentially caused by the low recall of the initial instance masks. Specifically, as shown in Fig. 2 (a), the initial instance masks are produced by the similarity map between the initial object queries and the point-wise mask features. Since the initial object queries are unstable in early training, we notice that the recall of initial instance masks is substantially lower than ours in Fig. 3, especially at the beginning of training (i.e., the 32-th epoch). The low-quality initial instance masks increase the training difficulty, + +![](images/c9d7f9030400789b78ebc3e1dbbfec373b103d4f6c0e18d7c34918cedd709a11.jpg) +Figure 2. The framework of (a) existing works (based on mask attention) and (b) ours. Existing works have the issue of low-recall initial instance masks (i.e., $\mathcal{M}_0$ ). Our approach resorts to an auxiliary center regression task to circumvent this issue. + +thereby slowing down convergence. + +Given the low recall of the initial instance masks, we abandon the mask attention design and instead construct an auxiliary center regression task to guide cross-attention, as depicted in Fig. 2 (b). To enable center regression, we develop a series of position-aware designs. Firstly, we maintain a set of learnable position queries, each of which denotes the position of its corresponding content query. They are densely distributed over the 3D space, and we require each query to attend to its local region. As a result, the queries can easily capture the objects in a scene with a higher recall, which is crucial in reducing training difficulty and accelerating convergence. + +In addition, we design the contextual relative position encoding for cross-attention. Compared to the mask attention used in previous works, our solution is more flexible since the attention weights are adjusted by relative positions instead of hard masking. Furthermore, we iteratively update the position queries to achieve more accurate representation. Finally, we introduce the center distances between predictions and ground truths in both matching and loss. + +In total, our contribution is three-fold. + +- We observe that existing transformer-based methods suffer from the low recall of initial instance masks, which causes training difficulty and slow convergence. +Instead of relying on mask attention, we construct an auxiliary center regression task to overcome the lowrecall issue and design a series of position-aware components accordingly. Our approach manifests faster convergence and demonstrates higher performance. +- Experiments show our approach achieves a new state-of-the-art result and demonstrates superior performance on various datasets including ScanNetv2, ScanNet200, and S3DIS. + +# 2. Related Work + +# 2.1. 3D Instance Segmentation + +3D instance segmentation is a fundamental task for 3D recognition [45, 46, 28, 6, 32, 36, 31, 35, 27, 24, 34, + +![](images/6d85ce4170994191cbf1e92e2cfbba931d0eab4ba3606b44d74fc623dd1442a4.jpg) +Figure 3. The recall of initial instance masks at the 32-th and 80-th training epoch. We compare the baseline trained with 512 epochs and ours trained with 128, 256, and 512 epochs. Since our approach does not produce initial instance masks before entering decoder layers, we make statistics on the instance masks output by the first decoder layer for both the baseline and ours. + +11]. The solutions can be categorized into detection-based, grouping-based and the new emerging transformer-based paradigms. Detection-based approaches [21, 2, 67] first detect the bounding boxes and then segment the fine-grained instance mask. On the other hand, grouping-based approaches [60, 61, 26, 17, 19, 25, 23, 20, 69, 33, 5, 55, 12, 10] employ clustering algorithms to group the points into a set of instance clusters. Before clustering, they either move 3D points towards the associated object center to form a more compact distribution [26, 19, 25, 23, 69, 33, 5, 55], or transform points to a high-dimension feature space [60, 61]. Further, a series of works leverage semantic priors to avoid the noisy points from other categories [26, 25, 33, 5, 55] or use advanced grouping strategies [55, 5, 33]. With these designs, the grouping-based paradigm has achieved leading performance across various evaluation benchmarks[1, 14] for a long time. Recently, transformer-based paradigm [49, 50] becomes another option and swiftly sets a new state-of-the-art. Compared with previous methods, it presents an elegant pipeline, and can directly output instance predictions. It relies on the transformer decoder and mask attention to aggregate information from global features. In this work, we construct an auxiliary center regression task to assist in cross-attention. Although the existing grouping-based methods also predict center offsets, we explain that ours is not for instance proposals, but to overcome the lowrecall issue and provide positional priors for cross-attention. + +# 2.2. Vision Transformer + +Transformer has become a fundamental model in the vision area, thanks to its flexibility and power to model various scenarios using attention mechanisms [54]. Re + +![](images/fdb0fc6b3c5aa90f360f3ed8e90077714876203d9e3fca7d9f763c6e218ee714.jpg) +Figure 4. The overview of our framework. Besides content queries $\mathcal{Q}_0^c$ , we also maintain a set of learnable position queries $\mathcal{Q}_0^p$ . The content queries $\mathcal{Q}^c$ aggregate features from the global features $\mathcal{F}$ . The position queries $\mathcal{Q}^p$ are designed to guide the cross-attention. The attention weights are adjusted based on the relative positions between the position queries $\mathcal{Q}^p$ and the global positions $\mathcal{P}$ . Both content and position queries are iteratively refined in each layer. Only 3 decoder layers are shown (we use 6 layers in our experiments). + +cently, many works [16, 52, 53, 59, 58, 13, 15, 51, 66] rely on the self-attention in transformers to develop vision fundamental models. Besides, DETR [3] proposes a fully end-to-end pipeline for object detection. It utilizes transformer decoders to dynamically aggregate features from images, and uses one-to-one bipartite matching for ground-truth assignment, yielding an elegant pipeline. To solve the notorious slow convergence of DETR, approaches [76, 62, 41, 37, 70, 68] propose deformable attention, impose strong prior or decrease searching space in cross-attention to accelerate convergence. Further, methods of [29, 39, 22, 71, 30] present several ways to stabilize matching and training. Moreover, masked attention [8, 7] are proposed to impose semantic priors to accelerate training for segmentation tasks. Recently, there are works [28, 73, 63, 64, 43, 49, 50] that develop transformer models tailored for 3D point clouds. Following this line of research, we observe the low recall of initial instance masks, and present solutions to circumvent the use of mask attention. + +# 3. Method + +We first review previous methods and present the overview of our method in Sec. 3.1. Then, we elaborate on the details of our position-aware designs in Sec. 3.2. + +# 3.1. Overview + +Preliminary. Recently, Mask3D [49] and SPFormer [50] present a fully end-to-end pipeline, which allows the object + +queries to directly output instance predictions. With transformer decoders, a fixed number of object queries aggregate information from the global features (either multi-scale voxel features [49] or superpoint features [50]) extracted with the backbone. Moreover, similar to Mask2Former [8, 7], they adopt mask attention and rely on the instance masks to guide the cross-attention. Specifically, the cross-attention is masked with the instance masks predicted in the last decoder layer, so that the queries only need to consider the masked features. However, as shown in Fig. 3, the recall of initial instance masks is low in the early stages of training. It hinders the ability to achieve a high-quality result in the subsequent layers and thus increases training difficulty. + +Ours. Instead of relying on mask attention, we propose an auxiliary center regression task to guide instance segmentation. The overview of our method is shown in Fig. 4 (a). We first yield the global positions $\mathcal{P} \in \mathbb{R}^{N \times 3}$ from the input point cloud and extract the global features $\mathcal{F} \in \mathbb{R}^{N \times d}$ using the backbone ( $\mathcal{P}$ and $\mathcal{F}$ can be either voxels [49] or superpoints [50] positions and features). In contrast to existing works, besides the content queries $\mathcal{Q}_0^c \in \mathbb{R}^{n \times d}$ , we also maintain a fixed number of position queries $\mathcal{Q}_0^p \in [0,1]^{n \times 3}$ that represent the normalized instance centers. $\mathcal{Q}_0^p$ is randomly initialized and $\mathcal{Q}_0^c$ is initialized with zero. Given the global positions $\mathcal{P}$ and global features $\mathcal{F}$ , our goal is to let the positional queries guide their corresponding content queries in cross-attention, and then iteratively refine both sets of queries, and finally predict the instance centers, classes and masks. For the $t$ -th decoder layer, this process + +![](images/17ffc6992a3a51b10149207fa5653ca8cf33c708a4f6e2d6e69aa6ace5bc1633.jpg) +Figure 5. The illustration for relative position encoding. We note the shape of the corresponding tensor at the bottom. + +is formulated as + +$$ +\mathbf {C e n t e r} _ {t} = \mathbf {M L P} _ {\text {c e n t e r}} \left(\mathbf {Q} _ {t} ^ {c}\right) + \mathbf {Q} _ {t - 1} ^ {p}, \tag {1} +$$ + +$$ +\mathbf {C l a s s} _ {t} = \mathbf {M L P} _ {c l s} \left(\mathbf {Q} _ {t} ^ {c}\right), \tag {2} +$$ + +$$ +\mathbf {M a s k} _ {t} = \sigma \left(\mathbf {Q} _ {t} ^ {c} \cdot \mathcal {F} _ {\text {m a s k}} ^ {T}\right) < 0. 5, \mathcal {F} _ {\text {m a s k}} = \mathbf {M L P} _ {\text {m a s k}} (\mathcal {F}), \tag {3} +$$ + +where $\mathbf{Center}_t\in \mathbb{R}^{n\times 3}$ , $\mathbf{Class}_t\in \mathbb{R}^{n\times K}$ and $\mathbf{Mask}_t\in \{0,1\}^{n\times N}$ are the predicted centers, classification logits, and the instance masks. + +# 3.2. Position-aware Designs + +To effectively support the center regression task and improve the recall of initial instance masks, we propose a series of position-aware designs as follows. + +Learnable Position Query. Unlike previous works [49, 50], we introduce an additional set of position queries $\mathcal{Q}_0^p\in [0,1]^{n\times 3}$ . Since the range of points varies significantly among different scenes, the initial position queries are stored in a normalized form as learnable parameters followed by sigmoid function. Basically, we can obtain the absolute positions $\hat{\mathcal{Q}}_t^p\in \mathbb{R}^{n\times 3}$ from the normalized position queries $\mathcal{Q}_t^p$ for a given input scene as + +$$ +\hat {\mathcal {Q}} _ {t} ^ {p} = \mathcal {Q} _ {t} ^ {p} \cdot \left(p _ {\max } - p _ {\min }\right) + p _ {\min }, \tag {4} +$$ + +where the $p_{min}, p_{max} \in \mathbb{R}^3$ represent the minimum and maximum coordinates of the input scene, respectively. The resultant $\hat{\mathcal{Q}}_t^p$ explicitly represents the positions of the corresponding content queries $\mathcal{Q}_t^c$ . + +It is notable that the initial position queries are densely spread throughout the 3D space. Also, every query aggregates features from its local region. This design choice makes it easier for the initial queries to capture the objects in a scene with a high recall, as shown in Fig. 3. It overcomes the low-recall issue caused by initial instance masks, and consequently reduces the training complexity of the subsequent layers. + +Relative Position Encoding. Other than the absolute position encoding (e.g., Fourier or sine transformations), we also adopt contextual relative position encoding in crossattention. Inspired by [28], we first calculate the relative positions $\mathbf{r} \in \mathbb{R}^{n \times N \times 3}$ between the position queries $\hat{\mathcal{Q}}_t^p \in \mathbb{R}^{n \times 3}$ and the global positions $\mathcal{P} \in \mathbb{R}^{N \times 3}$ , and quantize it into discrete integers $\hat{\mathbf{r}} \in \mathbb{Z}^{n \times N \times 3}$ as shown in Fig. 5. It is formulated as + +$$ +\mathbf {r} = \hat {\mathcal {Q}} _ {t} ^ {p} - \mathcal {P}, \quad \hat {\mathbf {r}} = \left\lfloor \frac {\mathbf {r}}{s} \right\rfloor + \frac {L}{2}, \tag {5} +$$ + +where $s$ denotes the quantization size, $L$ denotes the length of position encoding table. We plus $\frac{L}{2}$ to ensure the discrete relative positions are non-negative. + +Then, we use the discrete relative positions $\hat{\mathbf{r}}$ as indices to look up the corresponding position encoding tables $\mathbf{t} \in \mathbb{R}^{3 \times L \times d}$ , as illustrated in Fig. 5. Formally, the relative position encoding $\mathbf{f}^{pos} \in \mathbb{R}^{n \times N \times d}$ is yielded as + +$$ +\mathbf {f} ^ {\text {p o s}} = \mathbf {t} [ 0, \hat {\mathbf {r}} _ {x} ] + \mathbf {t} [ 1, \hat {\mathbf {r}} _ {y} ] + \mathbf {t} [ 2, \hat {\mathbf {r}} _ {z} ], \tag {6} +$$ + +where $\hat{\mathbf{r}}_x, \hat{\mathbf{r}}_y, \hat{\mathbf{r}}_z \in \mathbb{Z}^{n \times N}$ are the discrete relative positions along the $x, y$ , and $z$ -axis, respectively. + +Further, the relative position encoding $\mathbf{f}^{pos}$ performs dot product with the query features $\mathbf{f}^q\in \mathbb{R}^{n\times d}$ or key features $\mathbf{f}^k\in \mathbb{R}^{N\times d}$ in the cross-attention, which is formulated as + +$$ +\mathbf {p o s} _ {-} \mathbf {b i a s} _ {i, j} = \mathbf {f} _ {i, j} ^ {p o s} \cdot \mathbf {f} _ {i} ^ {q} + \mathbf {f} _ {i, j} ^ {p o s} \cdot \mathbf {f} _ {j} ^ {k}, \tag {7} +$$ + +where $\text{pos\_bias} \in \mathbb{R}^{n \times N}$ is the positional bias. It is then added to the cross-attention weights, followed by the softmax function, as shown in Fig. 4 (b). + +It is worth noting that the RPE offers a greater degree of flexibility and error-insensitivity, compared to mask attention. In essence, RPE can be likened to a soft mask that has the ability to adjust attention weights flexibly, instead of hard masking. Another advantage of RPE is that it integrates semantic information (e.g., object size and class) and thus can harvest local information selectively. This is accomplished by the interaction between the relative positions and the semantic features (i.e., $\mathbf{f}^q$ and $\mathbf{f}^k$ ). + +Iterative Refinement. Since the content queries in our decoder layers are updated regularly, it is not optimal to maintain frozen position queries throughout the decoding process. Additionally, the initial position queries are static, so it is beneficial to adapt them to the specific input scene in the subsequent layers. To that end, we iteratively refine the position queries based on the content queries. Specifically, as shown in Fig. 4 (b), we leverage an MLP to predict a center offset $\Delta p_{t}$ from the updated content query $Q_{t + 1}^{c}$ . We then add it to the previous position query $\hat{Q}_t^p$ as + +$$ +\Delta p _ {t} = \mathbf {M L P} _ {\text {c e n t e r}} \left(\mathcal {Q} _ {t + 1} ^ {c}\right), \tag {8} +$$ + +$$ +\hat {\mathcal {Q}} _ {t + 1} ^ {p} = \hat {\mathcal {Q}} _ {t} ^ {p} + \Delta p _ {t}. +$$ + +Center Matching & Loss. To eliminate the need for duplicate removal methods such as non-maximum suppression (NMS), bipartite matching is adopted during training. Existing works [49, 50] rely on semantic predictions and binary masks to match the ground truths. + +In contrast, to support center regression, we also incorporate center distance in bipartite matching. Since we require the queries to only attend to a local region, it is critical to ensure that they only match with nearby ground-truth objects. To achieve this, we adapt the matching costs formulation as follows + +$$ +\mathcal {C} _ {c l s} (k, \hat {k}) = \mathrm {C E} (\mathbf {C l a s s} _ {k}, \hat {k}), +$$ + +$$ +\mathcal {C} _ {d i c e} (k, \hat {k}) = \operatorname {D I C E} (\mathbf {M a s k} _ {k}, \mathbf {M a s k} _ {\hat {k}}), +$$ + +$$ +\mathcal {C} _ {b c e} (k, \hat {k}) = \operatorname {B C E} (\mathbf {M a s k} _ {k}, \mathbf {M a s k} _ {\hat {k}}), \tag {9} +$$ + +$$ +\begin{array}{l} \mathcal {C} _ {\text {c e n t e r}} (k, \hat {k}) = \mathrm {L} _ {1} (\mathbf {C e n t e r} _ {k}, \mathbf {C e n t e r} _ {\hat {k}}), \\ \mathcal {C} (k, \hat {k}) = \lambda_ {c l s} \mathcal {C} _ {c l s} (k, \hat {k}) + \lambda_ {d i c e} \mathcal {C} _ {d i c e} (k, \hat {k}) \\ + \lambda_ {b c e} \mathcal {C} _ {b c e} (k, \hat {k}) + \lambda_ {c e n t e r} \mathcal {C} _ {c e n t e r} (k, \hat {k}), \\ \end{array} +$$ + +where $k$ and $\hat{k}$ denotes a predicted and ground-truth instance, respectively, $\mathcal{C} \in \mathbb{R}^{n \times n_{inst}}$ denotes the matching cost matrix, and $\lambda$ denotes the cost weights. + +The Hungarian Algorithm is then applied on $\mathcal{C}$ to yield the one-to-one matching result $\hat{\sigma} \in \mathbb{Z}^n$ , which is followed by the loss function as + +$$ +\begin{array}{l} \hat {\sigma} = \arg \min _ {\sigma : \sigma_ {i} \neq \sigma_ {j}, \forall i \neq j} \sum_ {i = 1} ^ {n} \mathcal {C} (i, \sigma_ {i}), \\ \mathcal {L} = \lambda_ {c l s} \operatorname {C E} \left(\operatorname {C l a s s} _ {i}, \hat {\sigma} _ {i}\right) \tag {10} \\ + \lambda_ {d i c e} D I C E (\mathbf {M a s k} _ {i}, \mathbf {M a s k} _ {\sigma_ {i}}) \\ + \lambda_ {b c e} \operatorname {B C E} \left(\mathbf {M a s k} _ {i}, \mathbf {M a s k} _ {\hat {\sigma} _ {i}}\right) \\ + \lambda_ {c e n t e r} L _ {1} \left(\text {C e n t e r} _ {i}, \text {C e n t e r} _ {\hat {\sigma} _ {i}}\right). \\ \end{array} +$$ + +# 4. Experiment + +This section first provides an overview of the experimental setup in Sec. 4.1. We then present the 3D instance segmentation results in Sec. 4.2. Additionally, we conduct an extensive ablation study in Sec. 4.3. Furthermore, we showcase the object detection results and visual comparisons in Sections 4.4 and 4.5, respectively. Code and models will be made publicly available. + +# 4.1. Experimental Setting + +Network Architecture. For both ScanNetv2 [14] and ScanNet200 [47], we follow previous works [50, 25, 55, 5, 33] to use 5-layer U-Net as the backbone. The initial channel is set to 32. Unless otherwise specified, we use the coordinates and colors as the input features. We use 6 layers of Transformer decoders, where the head number is set to 8 and the hidden and feed-forward dimensions are set + +to 256 and 1024, respectively. We adopt Fourier absolute position encoding with the temperature set to 10,000. The quantization size for RPE is set to $0.1\mathrm{m}$ , and the length of the RPE table is 48. Unless otherwise specified, we choose [50] as the baseline model, since it has achieved the best performance on ScanNetv2 val set so far. For the S3DIS [1] dataset, following Mask3D [49], we use Res16UNet34C [9] as the backbone and employ 4 decoders to attend to the coarsest four scales, and this is repeated 3 times with the shared parameters. The decoder hidden and feed-forward dimensions are set to 128 and 1024, respectively. + +Datasets. We use the ScanNetv2 [14], ScanNet200 [47] and S3DIS [1] datasets for evaluation. All of them are challenging large-scale indoor scene datasets. + +The ScanNetv2 dataset comprises 1201 scenes for training, and an additional 312 and 100 indoor scenes for validation and testing, respectively. The scenes are captured with RGB-D cameras and annotated with 20 semantic labels, 18 of which are instance classes. The ScanNet200 dataset adopts the same point cloud data, but it offers more diverse annotations, covering 200 classes, 198 of which are instance classes. + +The S3DIS dataset contains 271 rooms in 6 areas of three buildings, and 13 semantic categories are annotated. Following previous works, the scenes in Area 5 are used for validation and the others are for training. + +Implementation Details. We adopt one RTX 3090 GPU for training on ScanNet and ScanNet200, and one A100 GPU on S3DIS. Following previous works, we use AdamW [40] optimizer with the learning rate and weight decay set to 0.0001 and 0.05, respectively. We adopt poly scheduler on ScanNet and ScanNet200, and oncycle scheduler on S3DIS. The batch size is set to 4. For the weights of matching costs and losses, $(\lambda_{cls}, \lambda_{bce}, \lambda_{dice}, \lambda_{center})$ are set to (0.5, 1.0, 1.0, 0.5) on ScanNet and ScanNet200, and (2.0, 5.0, 1.0, 0.5) on S3DIS. The voxel size is set to $0.02\mathrm{m}$ . We limit the points number up to 250,000. Otherwise, we crop the scene by cubic windows iteratively until the point number is lower than the limit. During inference, we select the top 100 instances with the highest scores and set the minimum points number per instance to 100. + +# 4.2. Instance Segmentation Results + +ScanNetv2. We present the results of instance segmentation on both the ScanNetv2 test and val sets in Tables 1 and 2, respectively. Our method achieves a considerable increase in mAP compared to previous works, suggesting a superior ability to capture fine-grained details and produce high-quality instance segmentation. While Mask3D [49] slightly outperforms our model in terms of $\mathrm{mAP}_{50}$ , it is worth noting that this is potentially due to their use of a + +
MethodmAP\( \mathrm{mAP}_{50} \)bathbedbkshfcabinetchaircountercurtaindeskdoorotherpicturefridges. cur.sinksofatabletoiletwind.
3D-BoNet [2]25.348.851.932.425.113.734.53.141.96.916.213.15.220.233.814.730.130.365.117.8
MTML [26]28.240.257.738.018.210.743.00.142.25.717.916.27.022.951.116.149.131.365.016.2
GICN [38]34.163.858.037.134.419.846.95.256.49.321.221.212.734.753.720.652.532.972.924.1
3D-MPA [17]35.561.145.748.429.927.759.14.733.221.221.727.819.341.341.019.557.435.284.921.3
Dyco3D [20]39.564.164.251.844.725.966.65.025.116.623.136.223.233.153.522.958.743.885.031.7
PE [69]39.664.566.746.744.624.362.42.257.710.621.934.023.948.747.522.554.135.081.827.3
PointGroup [25]40.763.663.949.641.524.364.52.157.011.421.135.921.742.866.625.656.234.186.029.1
HAIS [5]45.769.970.456.145.736.467.34.654.719.430.842.628.845.471.126.256.343.488.934.4
OccuSeg [19]48.667.280.253.642.836.970.220.533.130.137.947.432.743.786.248.560.139.484.627.3
SoftGroup [55]50.476.166.757.937.238.169.47.267.730.338.753.131.958.275.431.864.349.290.738.8
SSTNet [33]50.669.873.854.949.731.669.317.837.719.833.046.357.651.585.749.463.745.794.329.0
SPFormer [50]54.977.074.564.048.439.573.931.156.633.546.849.255.547.874.743.671.254.089.334.3
Mask3D* [49]56.678.092.659.740.842.073.723.959.838.645.854.956.871.660.148.064.657.592.236.4
Ours57.877.477.864.952.044.976.125.358.439.153.047.261.749.979.547.374.554.896.037.4
\( Ours^‡ \)59.678.688.972.144.846.076.825.155.840.850.453.961.661.885.848.268.455.193.145.0
+ +Table 1. 3D instance segmentation results on ScanNet test set. * denotes using Res16UNet34C (twice as many parameters as ours) as the backbone. ‡ denotes using surface normal. Methods published before the submission deadline (03/08/2023) are listed. + +
MethodmAP\( \mathrm{mAP}_{50} \)
GSPN [67]19.337.8
MTML [26]20.340.2
3D-MPA [17]35.559.1
Dyco3D [20]35.457.6
PointGroup [25]34.856.7
MaskGroup [75]42.063.3
HAIS [5]43.564.1
OccuSeg [19]44.260.7
SoftGroup [55]46.067.6
SSTNet [33]49.464.3
SPFormer [50]56.373.9
Mask3D* [49]55.273.7
Ours58.475.9
\( Ours^‡ \)59.976.5
+ +Table 2. 3D instance segmentation results on ScanNet val set. * denotes using Res16UNet34C (twice as many parameters as ours) as the backbone. ‡ denotes using surface normal. + +
MethodmAP\( \mathrm{mAP}_{50} \)\( \mathrm{mAP}_{25} \)
\( SPFormer^† \)[50]25.233.839.6
\( Mask3D* \)[49]27.437.042.3
Ours29.238.243.3
+ +stronger backbone (i.e., Res16UNet34C with twice as many parameters as ours) and DBSCAN post-processing. Despite this, our approach produces significantly better performance on the ScanNetv2 val set than Mask3D, as seen in Table 2. + +Table 3. 3D instance segmentation results on ScanNet200 val set. ${}^{ \dagger }$ denotes reproduced results. * denotes using Res16UNet34C. + +
Method\( \mathrm{mAP}_{50} \)\( \mathrm{mAP}_{25} \)
PointGroup [25]57.8-
MaskGroup [75]65.0-
SoftGroup [55]66.1-
SSTNet [33]59.3-
SPFormer [50]66.8-
Mask3D [49]68.475.2
Ours69.175.7
+ +Table 4. 3D instance segmentation results on S3DIS Area5. + +ScanNet200. Table 3 presents our comparison with previous state-of-the-art methods on the val set of ScanNet200. Our method achieves a significant improvement in comparison to the other methods. Consistent conclusion is also seen on this challenging dataset. It is important to note that previous works employ mask attention, while our approach does not. This verifies the success of our auxiliary center regression task in replacing mask attention. + +S3DIS. As shown in Table 4, our method is evaluated on S3DIS Area5. Our approach outperforms previous works. This consistently shows the superiority of our method. + +# 4.3. Ablation Study + +We conduct an extensive ablation study to verify each component of our method as follows. + +Learnable Position Query. The position query aims to provide an explicit center representation to the content query counterpart. Making it learnable intends to learn an optimal initial spatial distribution. We notice that some previous works [49, 42] adopt non-parametric initial queries, + +![](images/0edad6df79495ad3017dd380634cbb5ab028077c15896be3efbcaba7ed186299.jpg) +(a) + +![](images/0d64127831112475c83b6176a852b03bacd2d0459dc637cc5f5a5962cc559a76.jpg) +Figure 6. Spatial distribution of ground truths that are matched to the same query at different training iterations. (a): Baseline. (b): Ours. We randomly select 10 object queries and record their matched ground-truth instances in the early training. The three scatter plots for each method represent the center XYZ coordinates of their matched ground-truth instances at different training iterations (the scatter points for a query correspond to different training iterations). More visualization details are given in supplementary material. Our method manifests strong positional matching consistency among different training iterations. + +![](images/8abec5f17ba7e85a54a79f9db06931f258d6530af111400e265787719734ab24.jpg) + +![](images/5235d3b5118f3901a7cd038901c40dadcf3017a14e1f8e498621f0bf8dca2429.jpg) +(b) + +![](images/11fdca9eaf78ef11465e9fb216714abf81dd8ef8dcefdde63bf7b9846c226b75.jpg) + +
PositionContentmAP\( \mathrm{mAP}_{50} \)\( \mathrm{mAP}_{25} \)
FPSzero57.374.984.2
FPSlearnable57.175.083.4
learnablelearnable58.175.484.3
learnablezero58.475.984.5
+ +Table 5. Ablation study on different initializations for position and content queries. + +
Position EncodingmAP\( \mathrm{mAP}_{50} \)\( \mathrm{mAP}_{25} \)
No PE0.00.00.0
Fourier APE57.776.083.8
Content-conditioned APE58.075.784.3
RPE58.475.984.5
+ +Table 6. Ablation study on different position encodings. + +
IDiter. refinecenter matchcenter lossmAP\( \mathrm{mAP}_{50} \)\( \mathrm{mAP}_{25} \)
1✓✓57.575.384.0
2✓✓56.774.884.1
3✓✓56.874.684.5
4✓56.474.783.7
5✓✓✓58.475.984.5
+ +Table 7. Ablation study on iterative refinement and center matching & loss. + +where Furthest Point Sampling (FPS) is used to sample a number of points and transform them into position encodings via Fourier transformation followed by an MLP. We make comparisons in Table 5. The results show that learnable position query and zero-initialized content query perform best. A potential reason why 'FPS' lags behind 'learnable' is that the latter learns an optimal spatial distribution. + +Moreover, to show the pattern of the learnable position query, we visualize the spatial distribution of center coordinates of the matched ground truths for a query in Fig. 6. It shows that each query consistently attends to a local region. + +Relative Position Encoding. We compare various position encodings that are employed in previous works [49, 41], such as Fourier Absolute Position Encoding (APE) and the content query-conditioned APE. Specifically, the latter uses an MLP to project the content query into a $d$ -dim diagonal matrix, which then transforms the original absolute position encoding into a new one. It incorporates semantic information into the position encoding but does not consider relative relation. As shown in Table 6, RPE outperforms the others, which implies that both semantic information and relative relation are beneficial. Also, we notice that if we do not apply any position encoding, the training corrupts. This shows that positional prior is crucial in our framework. + +Iterative Refinement. We remove the iterative refinement and freeze the position query in all decoder layers, and we find that it causes a performance drop of $0.9\%$ mAP as shown in the first row of Table 7. This verifies the effectiveness of iterative refinement. + +Center Matching & Loss. Moreover, to manifest the importance of center matching and center loss, we also conduct ablation studies in Table 7. We first remove the center matching and keep the center loss in the second row of the table, and we find that the performance drops by $1.7\%$ mAP. Then we keep the center matching and remove the center loss. The performance also decreases by $1.6\%$ mAP as shown in the 3-rd row. When both are absent, we observe an even larger performance drop $(2.0\% \mathrm{mAP})$ in the 4-th row. The results reveal that both center matching and loss are important to our framework. + +# 4.4. Object Detection Results + +The instance predictions of instance segmentation can be easily transformed into bounding box predictions, by obtaining the minimum and maximum coordinates of the masked instances. We empirically find that the generated object detection results from the instance predictions work + +![](images/aff190b6b9477aeeab9ba6519fdd0de0bfdbf48ee560fb2b20d10d5f0c6345d3.jpg) + +
Methodtaskbox mAP50box mAP25
VoteNet [44]det33.558.6
HGNet [4]det34.461.3
MLCVNet [65]det41.464.5
GSDN [18]det34.862.8
H3DNet [72]det48.167.2
3DETR [42]det47.065.0
Group-free [39]det52.869.1
RBGNet [57]det55.270.6
HyperDet3D [74]det57.270.9
FCAF3D [48]det57.371.5
CAGroup3D [56]det61.375.1
3D-MPA [17]inst49.264.2
Mask3D [49]inst56.270.2
Oursinst63.973.5
+ +Table 8. 3D object detection results on ScanNetv2. For methods designed for the instance segmentation task, the bounding boxes are generated by the instance mask predictions. + +significantly better than previous methods tailored for 3D object detection in terms of $\mathrm{mAP}_{50}$ , as shown in Table 8. This finding also shows that our approach outputs high-quality instance segmentation results with fewer artifacts. + +# 4.5. Visual Comparison + +We visually compare our approach with previous state-of-the-art methods in Fig. 7. More examples are given in + +the supplementary material. The visualizations demonstrate that our method tends to correctly recognize the classes of the instances. It implies that our approach is able to generate more high-quality instance segmentation results. + +# 5. Conclusion + +In this work, we have presented a mask-attention-free transformer for the 3D instance segmentation task. We first observe the issue of low-recall of the initial masks in existing works. It adds training difficulty and slows down convergence. We thus avoid using mask attention and instead propose an auxiliary center regression task to guide the cross-attention. To fit center regression, we develop a series of designs. A dense distribution of position queries is learned to yield a higher recall of the perceived instances. Also, relative position encoding and iterative refinement are designed to further boost the performance. Each component is verified to be effective. + +# Acknowledgements + +This work was supported in part by the Research Grants Council under the Areas of Excellence scheme grant AoE/E-601/22-R and Shenzhen Science and Technology Program KQTD20210811090149095. + +# References + +[1] Iro Armeni, Ozan Sener, Amir R. Zamir, Helen Jiang, Ioannis Brilakis, Martin Fischer, and Silvio Savarese. 3d semantic parsing of large-scale indoor spaces. In CVPR, 2016. 2, 5 +[2] Yang Bo, Wang Jianan, Clark Ronald, Hu Qingyong, Wang Sen, Markham Andrew, and Trigoni Niki. Learning object bounding boxes for 3d instance segmentation on point clouds. In NeurIPS, pages 6737-6746, 2019. 2, 6 +[3] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In ECCV, 2020. 3 +[4] Jintai Chen, Biwen Lei, Qingyu Song, Haochao Ying, Danny Z Chen, and Jian Wu. A hierarchical graph network for 3d object detection on point clouds. In CVPR, 2020. 8 +[5] Shaoyu Chen, Jiemin Fang, Qian Zhang, Wenyu Liu, and Xinggang Wang. Hierarchical aggregation for 3d instance segmentation. In ICCV, pages 15467-15476, 2021. 1, 2, 5, 6 +[6] Yukang Chen, Yanwei Li, Xiangyu Zhang, Jian Sun, and Jiaya Jia. Focal sparse convolutional networks for 3d object detection. In CVPR, 2022. 2 +[7] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In CVPR, 2022. 3 +[8] Bowen Cheng, Alex Schwing, and Alexander Kirillov. Per-pixel classification is not all you need for semantic segmentation. NeurIPS, 2021. 3 +[9] Christopher Choy, JunYoung Gwak, and Silvio Savarese. 4d spatio-temporal convnets: Minkowski convolutional neural networks. In CVPR, 2019. 5 +[10] Ruihang Chu, Yukang Chen, Tao Kong, Lu Qi, and Lei Li. Icm-3d: Instantiated category modeling for 3d instance segmentation. IEEE Robotics and Automation Letters, 7(1):57-64, 2021. 2 +[11] Ruihang Chu, Zhengzhe Liu, Xiaqing Ye, Xiao Tan, Xiaojuan Qi, Chi-Wing Fu, and Jiaya Jia. Command-driven articulated object understanding and manipulation. In CVPR, 2023. 2 +[12] Ruihang Chu, Xiaqing Ye, Zhengzhe Liu, Xiao Tan, Xiaojuan Qi, Chi-Wing Fu, and Jiaya Jia. Twist: Two-way inter-label self-training for semi-supervised 3d instance segmentation. In CVPR, 2022. 2 +[13] Xiangxiang Chu, Zhi Tian, Yuqing Wang, Bo Zhang, Haibing Ren, Xiaolin Wei, Huaxia Xia, and Chunhua Shen. Twins: Revisiting the design of spatial attention in vision transformers. arXiv:2104.13840, 2021. 3 +[14] Angela Dai, Angel X. Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In CVPR, 2017. 2, 5 +[15] Xiaoyi Dong, Jianmin Bao, Dongdong Chen, Weiming Zhang, Nenghai Yu, Lu Yuan, Dong Chen, and Baining Guo. Cswin transformer: A general vision transformer backbone with cross-shaped windows. arXiv:2107.00652, 2021. 3 + +[16] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. ICLR, 2021. 3 +[17] Francis Engelmann, Martin Bokeloh, Alireza Fathi, Bastian Leibe, and Matthias Nießner. 3d-mpa: Multi-proposal aggregation for 3d semantic instance segmentation. In CVPR, pages 9031-9040, 2020. 2, 6, 8 +[18] JunYoung Gwak, Christopher Choy, and Silvio Savarese. Generative sparse detection networks for 3d single-shot object detection. In ECCV, 2020. 8 +[19] Lei Han, Tian Zheng, Lan Xu, and Lu Fang. Occuseg: Occupancy-aware 3d instance segmentation. In CVPR, pages 2940-2949, 2020. 2, 6 +[20] Tong He, Chunhua Shen, and Anton van den Hengel. Dyco3d: Robust instance segmentation of 3d point clouds through dynamic convolution. In CVPR, pages 354-363, 2021. 2, 6 +[21] Ji Hou, Angela Dai, and Matthias Nießner. 3d-sis: 3d semantic instance segmentation of rgb-d scans. In CVPR, pages 4421-4430, 2019. 2 +[22] Ding Jia, Yuhui Yuan, Haodi He, Xiaopei Wu, Haojun Yu, Weihong Lin, Lei Sun, Chao Zhang, and Han Hu. Detrs with hybrid matching. arXiv preprint, 2022. 3 +[23] Haiyong Jiang, Feilong Yan, Jianfei Cai, Jianmin Zheng, and Jun Xiao. End-to-end 3d point cloud instance segmentation without detection. In CVPR, pages 12796-12805, 2020. 2 +[24] Li Jiang, Shaoshuai Shi, Zhuotao Tian, Xin Lai, Shu Liu, Chi-Wing Fu, and Jiaya Jia. Guided point contrastive learning for semi-supervised point cloud semantic segmentation. In ICCV, 2021. 2 +[25] Li Jiang, Hengshuang Zhao, Shaoshuai Shi, Shu Liu, ChiWing Fu, and Jiaya Jia. Pointgroup: Dual-set point grouping for 3d instance segmentation. In CVPR, pages 4867-4876, 2020. 1, 2, 5, 6 +[26] Jean Lahoud, Bernard Ghanem, Marc Pollefeys, and Martin R Oswald. 3d instance segmentation via multi-task metric learning. In ICCV, pages 9256-9266, 2019. 2, 6 +[27] Xin Lai, Yukang Chen, Fanbin Lu, Jianhui Liu, and Jiaya Jia. Spherical transformer for lidar-based 3d recognition. In CVPR, 2023. 2 +[28] Xin Lai, Jianhui Liu, Li Jiang, Liwei Wang, Hengshuang Zhao, Shu Liu, Xiaojuan Qi, and Jiaya Jia. Stratified transformer for 3d point cloud segmentation. In CVPR, 2022. 2, 3, 4 +[29] Feng Li, Hao Zhang, Shilong Liu, Jian Guo, Lionel M Ni, and Lei Zhang. Dn-detr: Accelerate detr training by introducing query denoising. In CVPR, 2022. 3 +[30] Feng Li, Hao Zhang, Shilong Liu, Lei Zhang, Lionel M Ni, Heung-Yeung Shum, et al. Mask dino: Towards a unified transformer-based framework for object detection and segmentation. arXiv preprint, 2022. 3 +[31] Yanwei Li, Yilun Chen, Xiaojuan Qi, Zeming Li, Jian Sun, and Jiaya Jia. Unifying voxel-based representation with transformer for 3d object detection. NeurIPS, 2022. 2 + +[32] Yanwei Li, Xiaojuan Qi, Yukang Chen, Liwei Wang, Zeming Li, Jian Sun, and Jiaya Jia. Voxel field fusion for 3d object detection. In CVPR, 2022. 2 +[33] Zhihao Liang, Zhihao Li, Songcen Xu, Mingkui Tan, and Kui Jia. Instance segmentation in 3d scenes using semantic superpoint tree networks. In ICCV, 2021. 2, 5, 6 +[34] Jiahui Liu, Chirui Chang, Jianhui Liu, Xiaoyang Wu, Lan Ma, and Xiaojuan Qi. Mars3d: A plug-and-play motion-aware model for semantic segmentation on multi-scan 3d point clouds. In CVPR, 2023. 2 +[35] Jianhui Liu, Yukang Chen, Xiaqing Ye, and Xiaojuan Qi. Prior-free category-level pose estimation with implicit space transformation. arXiv preprint arXiv:2303.13479, 2023. 2 +[36] Jianhui Liu, Yukang Chen, Xiaqing Ye, Zhuotao Tian, Xiao Tan, and Xiaojuan Qi. Spatial pruned sparse convolution for efficient 3d object detection. NeurIPS, 2022. 2 +[37] Shilong Liu, Feng Li, Hao Zhang, Xiao Yang, Xianbiao Qi, Hang Su, Jun Zhu, and Lei Zhang. Dab-detr: Dynamic anchor boxes are better queries for detr. In ICLR, 2022. 3 +[38] Shih-Hung Liu, Shang-Yi Yu, Shao-Chi Wu, Hwann-Tzong Chen, and Tyng-Luh Liu. Learning gaussian instance segmentation in point clouds. arXiv preprint, 2020. 6 +[39] Ze Liu, Zheng Zhang, Yue Cao, Han Hu, and Xin Tong. Group-free 3d object detection via transformers. In ICCV, 2021. 3, 8 +[40] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. arXiv:1711.05101, 2017. 5 +[41] Depu Meng, Xiaokang Chen, Zejia Fan, Gang Zeng, Houqiang Li, Yuhui Yuan, Lei Sun, and Jingdong Wang. Conditional detr for fast training convergence. In ICCV, 2021. 3, 7 +[42] Ishan Misra, Rohit Girdhar, and Armand Joulin. An end-to-end transformer model for 3d object detection. In ICCV, 2021. 6, 8 +[43] Chunghyun Park, Yoonwoo Jeong, Minsu Cho, and Jaesik Park. Fast point transformer. In CVPR, 2022. 3 +[44] Charles R Qi, Or Litany, Kaiming He, and Leonidas J Guibas. Deep hough voting for 3d object detection in point clouds. In ICCV, 2019. 8 +[45] Charles R Qi, Hao Su, Kaichun Mo, and Leonidas J Guibas. Pointnet: Deep learning on point sets for 3d classification and segmentation. In CVPR, 2017. 2 +[46] Charles Ruizhongtai Qi, Li Yi, Hao Su, and Leonidas J Guibas. Pointnet++: Deep hierarchical feature learning on point sets in a metric space. NeurIPS, 2017. 2 +[47] David Rozenberszki, Or Litany, and Angela Dai. Language-grounded indoor 3d semantic segmentation in the wild. In ECCV, 2022. 5 +[48] Danila Rukhovich, Anna Vorontsova, and Anton Konushin. Fcaf3d: fully convolutional anchor-free 3d object detection. In ECCV, 2022. 8 +[49] Jonas Schult, Francis Engelmann, Alexander Hermans, Or Litany, Siyu Tang, and Bastian Leibe. Mask3d for 3d semantic instance segmentation. ICRA, 2023. 1, 2, 3, 4, 5, 6, 7, 8 +[50] Jiahao Sun, Chunmei Qing, Junpeng Tan, and Xiangmin Xu. Superpoint transformer for 3d scene instance segmentation. AAAI, 2023. 1, 2, 3, 4, 5, 6 + +[51] Shuyang Sun, Xiaoyu Yue, Song Bai, and Philip Torr. Visual parser: Representing part-whole hierarchies with transformers. arXiv:2107.05790, 2021. 3 +[52] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Herve Jegou. Training data-efficient image transformers & distillation through attention. In ICML, 2021. 3 +[53] Hugo Touvron, Matthieu Cord, Alexandre Sablayrolles, Gabriel Synnaeve, and Hervé Jégou. Going deeper with image transformers. arXiv:2103.17239, 2021. 3 +[54] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In NeurIPS, 2017. 2 +[55] Thang Vu, Kookhoi Kim, Tung M Luu, Thanh Nguyen, and Chang D Yoo. Softgroup for 3d instance segmentation on point clouds. In CVPR, 2022. 1, 2, 5, 6 +[56] Haiyang Wang, Lihe Ding, Shaocong Dong, Shaoshuai Shi, Aoxue Li, Jianan Li, Zhenguo Li, and Liwei Wang. Cagroup3d: Class-aware grouping for 3d object detection on point clouds. In NeurIPS, 2022. 8 +[57] Haiyang Wang, Shaoshuai Shi, Ze Yang, Rongyao Fang, Qi Qian, Hongsheng Li, Bernt Schiele, and Liwei Wang. Rbgnet: Ray-based grouping for 3d object detection. In CVPR, 2022. 8 +[58] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pvtv2: Improved baselines with pyramid vision transformer. arXiv:2106.13797, 2021. 3 +[59] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In ICCV, 2021. 3 +[60] Weiyue Wang, Ronald Yu, Qiangui Huang, and Ulrich Neumann. Sgpn: Similarity group proposal network for 3d point cloud instance segmentation. In CVPR, pages 2569-2578, 2018. 2 +[61] Xinlong Wang, Shu Liu, Xiaoyong Shen, Chunhua Shen, and Jiaya Jia. Associatively segmenting instances and semantics in point clouds. In CVPR, pages 4096-4105, 2019. 2 +[62] Yingming Wang, Xiangyu Zhang, Tong Yang, and Jian Sun. Anchor detr: Query design for transformer-based detector. In AAAI, 2022. 3 +[63] Wenxuan Wu, Qi Shan, and Li Fuxin. Pointconvformer: Re-venge of the point-based convolution. arXiv preprint, 2022. 3 +[64] Xiaoyang Wu, Yixing Lao, Li Jiang, Xihui Liu, and Hengshuang Zhao. Point transformer v2: Grouped vector attention and partition-based pooling. NeurIPS, 2022. 3 +[65] Qian Xie, Yu-Kun Lai, Jing Wu, Zhoutao Wang, Yiming Zhang, Kai Xu, and Jun Wang. Mlcvnet: Multi-level context votenet for 3d object detection. In CVPR, 2020. 8 +[66] Jianwei Yang, Chunyuan Li, Pengchuan Zhang, Xiyang Dai, Bin Xiao, Lu Yuan, and Jianfeng Gao. Focal self-attention for local-global interactions in vision transformers. In NeurIPS, 2021. 3 +[67] Li Yi, Wang Zhao, He Wang, Minhyuk Sung, and Leonidas J Guibas. Gspn: Generative shape proposal network for 3d + +instance segmentation in point cloud. In CVPR, pages 3947-3956, 2019. 2, 6 +[68] Qihang Yu, Huiyu Wang, Siyuan Qiao, Maxwell Collins, Yukun Zhu, Hartwig Adam, Alan Yuille, and Liang-Chieh Chen. k-means mask transformer. In ECCV, 2022. 3 +[69] Biao Zhang and Peter Wonka. Point cloud instance segmentation using probabilistic embeddings. In CVPR, pages 8883-8892, 2021. 2, 6 +[70] Gongjie Zhang, Zhipeng Luo, Yingchen Yu, Kaiwen Cui, and Shijian Lu. Accelerating detr convergence via semantic-aligned matching. In CVPR, 2022. 3 +[71] Hao Zhang, Feng Li, Shilong Liu, Lei Zhang, Hang Su, Jun Zhu, Lionel Ni, and Harry Shum. Dino: Detr with improved denoising anchor boxes for end-to-end object detection. In ICLR, 2022. 3 +[72] Zaiwei Zhang, Bo Sun, Haitao Yang, and Qixing Huang. H3dnet: 3d object detection using hybrid geometric primitives. In ECCV, 2020. 8 +[73] Hengshuang Zhao, Li Jiang, Jiaya Jia, Philip HS Torr, and Vladlen Koltun. Point transformer. In ICCV, 2021. 3 +[74] Yu Zheng, Yueqi Duan, Jiwen Lu, Jie Zhou, and Qi Tian. Hyperdet3d: Learning a scene-conditioned 3d object detector. In CVPR, 2022. 8 +[75] Min Zhong, Xinghao Chen, Xiaokang Chen, Gang Zeng, and Yunhe Wang. Maskgroup: Hierarchical point grouping and masking for 3d instance segmentation. In ICME, 2022. 1, 6 +[76] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable detr: Deformable transformers for end-to-end object detection. In ICLR, 2020. 3 \ No newline at end of file diff --git a/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/images.zip b/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..cef2b97f57c9c09a7e029dd35ec733e423bead80 --- /dev/null +++ b/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:4b2b0d8e49f732be394a2228a478b5bfd1db7ea90b55500cb8f7313f9dd02a24 +size 812315 diff --git a/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/layout.json b/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..cb839b4ae1df0ac8b48a0498dfa0293f4b5e4d10 --- /dev/null +++ b/2023/Mask-Attention-Free Transformer for 3D Instance Segmentation/layout.json @@ -0,0 +1,9237 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 96, + 103, + 498, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 96, + 103, + 498, + 121 + ], + "spans": [ + { + "bbox": [ + 96, + 103, + 498, + 121 + ], + "type": "text", + "content": "Mask-Attention-Free Transformer for 3D Instance Segmentation" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 56, + 141, + 287, + 174 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 141, + 287, + 174 + ], + "spans": [ + { + "bbox": [ + 56, + 141, + 287, + 174 + ], + "type": "text", + "content": "Xin Lai1 Yuhui Yuan3 Ruihang Chu1 \n1The Chinese University of Hong Kong" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 294, + 141, + 541, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 141, + 541, + 171 + ], + "spans": [ + { + "bbox": [ + 294, + 141, + 541, + 171 + ], + "type": "text", + "content": "Yukang Chen" + }, + { + "bbox": [ + 294, + 141, + 541, + 171 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 294, + 141, + 541, + 171 + ], + "type": "text", + "content": " Han Hu" + }, + { + "bbox": [ + 294, + 141, + 541, + 171 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 294, + 141, + 541, + 171 + ], + "type": "text", + "content": " Jiaya Jia" + }, + { + "bbox": [ + 294, + 141, + 541, + 171 + ], + "type": "inline_equation", + "content": "^{1,2*}" + }, + { + "bbox": [ + 294, + 141, + 541, + 171 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 294, + 141, + 541, + 171 + ], + "type": "text", + "content": "SmartMore " + }, + { + "bbox": [ + 294, + 141, + 541, + 171 + ], + "type": "inline_equation", + "content": "{ }^{3}" + }, + { + "bbox": [ + 294, + 141, + 541, + 171 + ], + "type": "text", + "content": "Microsoft Research Asia" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 199, + 192, + 212 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 199, + 192, + 212 + ], + "spans": [ + { + "bbox": [ + 143, + 199, + 192, + 212 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 224, + 290, + 523 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 224, + 290, + 523 + ], + "spans": [ + { + "bbox": [ + 47, + 224, + 290, + 523 + ], + "type": "text", + "content": "Recently, transformer-based methods have dominated 3D instance segmentation, where mask attention is commonly involved. Specifically, object queries are guided by the initial instance masks in the first cross-attention, and then iteratively refine themselves in a similar manner. However, we observe that the mask-attention pipeline usually leads to slow convergence due to low-recall initial instance masks. Therefore, we abandon the mask attention design and resort to an auxiliary center regression task instead. Through center regression, we effectively overcome the low-recall issue and perform cross-attention by imposing positional prior. To reach this goal, we develop a series of position-aware designs. First, we learn a spatial distribution of 3D locations as the initial position queries. They spread over the 3D space densely, and thus can easily capture the objects in a scene with a high recall. Moreover, we present relative position encoding for the cross-attention and iterative refinement for more accurate position queries. Experiments show that our approach converges " + }, + { + "bbox": [ + 47, + 224, + 290, + 523 + ], + "type": "inline_equation", + "content": "4\\times" + }, + { + "bbox": [ + 47, + 224, + 290, + 523 + ], + "type": "text", + "content": " faster than existing work, sets a new state of the art on ScanNetv2 3D instance segmentation benchmark, and also demonstrates superior performance across various datasets. Code and models are available at https://github.com/dvlab-research/Mask-Attention-Free-Transformer." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 544, + 128, + 557 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 544, + 128, + 557 + ], + "spans": [ + { + "bbox": [ + 47, + 544, + 128, + 557 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 564, + 287, + 637 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 564, + 287, + 637 + ], + "spans": [ + { + "bbox": [ + 46, + 564, + 287, + 637 + ], + "type": "text", + "content": "Nowadays 3D point clouds can be conveniently collected. They have benefited various applications, such as autonomous driving, robotics, and augmented reality. As a fundamental task, 3D instance segmentation also poses great challenges simultaneously, such as geometric occlusion and semantic ambiguity." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 637, + 288, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 637, + 288, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 637, + 288, + 696 + ], + "type": "text", + "content": "Many works have been proposed to solve the 3D instance segmentation task. Grouping-based methods [25, 55, 5, 75] rely on heuristic clustering algorithms such as DBSCAN or Breadth-First Search (BFS) to generate instance proposals. They thus require sophisticated hyper-parameters" + } + ] + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 316, + 201, + 536, + 379 + ], + "blocks": [ + { + "bbox": [ + 316, + 201, + 536, + 379 + ], + "lines": [ + { + "bbox": [ + 316, + 201, + 536, + 379 + ], + "spans": [ + { + "bbox": [ + 316, + 201, + 536, + 379 + ], + "type": "image", + "image_path": "618eb093ee1d77ccda03fa2bf3a161b9c7c9d4c63897dad16e183746fe163f50.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 380, + 547, + 415 + ], + "lines": [ + { + "bbox": [ + 305, + 380, + 547, + 415 + ], + "spans": [ + { + "bbox": [ + 305, + 380, + 547, + 415 + ], + "type": "text", + "content": "Figure 1. Validation curve of the baseline and ours on ScanNetv2 val set. With only 128-epoch training, ours outperforms the baseline trained with 512 epochs." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 426, + 547, + 545 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 426, + 547, + 545 + ], + "spans": [ + { + "bbox": [ + 304, + 426, + 547, + 545 + ], + "type": "text", + "content": "tuning and are prone to wrongly segment instances that are close to each other. Recently, transformer-based methods [49, 50] develop a fully end-to-end pipeline. With transformer decoder layers, a fixed number of object queries attend to global features iteratively and directly output instance predictions. It requires no post-processing for duplicate removal such as NMS, since it adopts one-to-one bipartite matching during training. Moreover, it employs mask attention, which uses the instance masks predicted in the last layer to guide the cross-attention." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 546, + 548, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 546, + 548, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 546, + 548, + 714 + ], + "type": "text", + "content": "However, we point out that current transformer-based methods suffer from the issue of slow convergence. As shown in Fig. 1, the baseline model manifests slow convergence and lags behind our method by a large margin, particularly in the early stages of training. We dive further and find that the issue is potentially caused by the low recall of the initial instance masks. Specifically, as shown in Fig. 2 (a), the initial instance masks are produced by the similarity map between the initial object queries and the point-wise mask features. Since the initial object queries are unstable in early training, we notice that the recall of initial instance masks is substantially lower than ours in Fig. 3, especially at the beginning of training (i.e., the 32-th epoch). The low-quality initial instance masks increase the training difficulty," + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 703, + 137, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 703, + 137, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 703, + 137, + 712 + ], + "type": "text", + "content": "*Corresponding Author" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3693" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 71, + 286, + 157 + ], + "blocks": [ + { + "bbox": [ + 50, + 71, + 286, + 157 + ], + "lines": [ + { + "bbox": [ + 50, + 71, + 286, + 157 + ], + "spans": [ + { + "bbox": [ + 50, + 71, + 286, + 157 + ], + "type": "image", + "image_path": "c9d7f9030400789b78ebc3e1dbbfec373b103d4f6c0e18d7c34918cedd709a11.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 159, + 287, + 204 + ], + "lines": [ + { + "bbox": [ + 46, + 159, + 287, + 204 + ], + "spans": [ + { + "bbox": [ + 46, + 159, + 287, + 204 + ], + "type": "text", + "content": "Figure 2. The framework of (a) existing works (based on mask attention) and (b) ours. Existing works have the issue of low-recall initial instance masks (i.e., " + }, + { + "bbox": [ + 46, + 159, + 287, + 204 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_0" + }, + { + "bbox": [ + 46, + 159, + 287, + 204 + ], + "type": "text", + "content": "). Our approach resorts to an auxiliary center regression task to circumvent this issue." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 219, + 193, + 230 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 219, + 193, + 230 + ], + "spans": [ + { + "bbox": [ + 47, + 219, + 193, + 230 + ], + "type": "text", + "content": "thereby slowing down convergence." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 231, + 287, + 374 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 231, + 287, + 374 + ], + "spans": [ + { + "bbox": [ + 46, + 231, + 287, + 374 + ], + "type": "text", + "content": "Given the low recall of the initial instance masks, we abandon the mask attention design and instead construct an auxiliary center regression task to guide cross-attention, as depicted in Fig. 2 (b). To enable center regression, we develop a series of position-aware designs. Firstly, we maintain a set of learnable position queries, each of which denotes the position of its corresponding content query. They are densely distributed over the 3D space, and we require each query to attend to its local region. As a result, the queries can easily capture the objects in a scene with a higher recall, which is crucial in reducing training difficulty and accelerating convergence." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 374, + 287, + 469 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 374, + 287, + 469 + ], + "spans": [ + { + "bbox": [ + 46, + 374, + 287, + 469 + ], + "type": "text", + "content": "In addition, we design the contextual relative position encoding for cross-attention. Compared to the mask attention used in previous works, our solution is more flexible since the attention weights are adjusted by relative positions instead of hard masking. Furthermore, we iteratively update the position queries to achieve more accurate representation. Finally, we introduce the center distances between predictions and ground truths in both matching and loss." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 59, + 470, + 213, + 480 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 470, + 213, + 480 + ], + "spans": [ + { + "bbox": [ + 59, + 470, + 213, + 480 + ], + "type": "text", + "content": "In total, our contribution is three-fold." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 58, + 487, + 287, + 643 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 58, + 487, + 286, + 522 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 487, + 286, + 522 + ], + "spans": [ + { + "bbox": [ + 58, + 487, + 286, + 522 + ], + "type": "text", + "content": "- We observe that existing transformer-based methods suffer from the low recall of initial instance masks, which causes training difficulty and slow convergence." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 58, + 530, + 287, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 530, + 287, + 590 + ], + "spans": [ + { + "bbox": [ + 58, + 530, + 287, + 590 + ], + "type": "text", + "content": "Instead of relying on mask attention, we construct an auxiliary center regression task to overcome the lowrecall issue and design a series of position-aware components accordingly. Our approach manifests faster convergence and demonstrates higher performance." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 58, + 597, + 286, + 643 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 597, + 286, + 643 + ], + "spans": [ + { + "bbox": [ + 58, + 597, + 286, + 643 + ], + "type": "text", + "content": "- Experiments show our approach achieves a new state-of-the-art result and demonstrates superior performance on various datasets including ScanNetv2, ScanNet200, and S3DIS." + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 47, + 651, + 134, + 662 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 651, + 134, + 662 + ], + "spans": [ + { + "bbox": [ + 47, + 651, + 134, + 662 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 671, + 192, + 684 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 671, + 192, + 684 + ], + "spans": [ + { + "bbox": [ + 47, + 671, + 192, + 684 + ], + "type": "text", + "content": "2.1. 3D Instance Segmentation" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 689, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 689, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 689, + 287, + 713 + ], + "type": "text", + "content": "3D instance segmentation is a fundamental task for 3D recognition [45, 46, 28, 6, 32, 36, 31, 35, 27, 24, 34," + } + ] + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 322, + 77, + 533, + 238 + ], + "blocks": [ + { + "bbox": [ + 322, + 77, + 533, + 238 + ], + "lines": [ + { + "bbox": [ + 322, + 77, + 533, + 238 + ], + "spans": [ + { + "bbox": [ + 322, + 77, + 533, + 238 + ], + "type": "image", + "image_path": "6d85ce4170994191cbf1e92e2cfbba931d0eab4ba3606b44d74fc623dd1442a4.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 240, + 545, + 306 + ], + "lines": [ + { + "bbox": [ + 304, + 240, + 545, + 306 + ], + "spans": [ + { + "bbox": [ + 304, + 240, + 545, + 306 + ], + "type": "text", + "content": "Figure 3. The recall of initial instance masks at the 32-th and 80-th training epoch. We compare the baseline trained with 512 epochs and ours trained with 128, 256, and 512 epochs. Since our approach does not produce initial instance masks before entering decoder layers, we make statistics on the instance masks output by the first decoder layer for both the baseline and ours." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 323, + 545, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 323, + 545, + 647 + ], + "spans": [ + { + "bbox": [ + 304, + 323, + 545, + 647 + ], + "type": "text", + "content": "11]. The solutions can be categorized into detection-based, grouping-based and the new emerging transformer-based paradigms. Detection-based approaches [21, 2, 67] first detect the bounding boxes and then segment the fine-grained instance mask. On the other hand, grouping-based approaches [60, 61, 26, 17, 19, 25, 23, 20, 69, 33, 5, 55, 12, 10] employ clustering algorithms to group the points into a set of instance clusters. Before clustering, they either move 3D points towards the associated object center to form a more compact distribution [26, 19, 25, 23, 69, 33, 5, 55], or transform points to a high-dimension feature space [60, 61]. Further, a series of works leverage semantic priors to avoid the noisy points from other categories [26, 25, 33, 5, 55] or use advanced grouping strategies [55, 5, 33]. With these designs, the grouping-based paradigm has achieved leading performance across various evaluation benchmarks[1, 14] for a long time. Recently, transformer-based paradigm [49, 50] becomes another option and swiftly sets a new state-of-the-art. Compared with previous methods, it presents an elegant pipeline, and can directly output instance predictions. It relies on the transformer decoder and mask attention to aggregate information from global features. In this work, we construct an auxiliary center regression task to assist in cross-attention. Although the existing grouping-based methods also predict center offsets, we explain that ours is not for instance proposals, but to overcome the lowrecall issue and provide positional priors for cross-attention." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 658, + 421, + 669 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 658, + 421, + 669 + ], + "spans": [ + { + "bbox": [ + 306, + 658, + 421, + 669 + ], + "type": "text", + "content": "2.2. Vision Transformer" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "content": "Transformer has become a fundamental model in the vision area, thanks to its flexibility and power to model various scenarios using attention mechanisms [54]. Re" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3694" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 71, + 544, + 292 + ], + "blocks": [ + { + "bbox": [ + 49, + 71, + 544, + 292 + ], + "lines": [ + { + "bbox": [ + 49, + 71, + 544, + 292 + ], + "spans": [ + { + "bbox": [ + 49, + 71, + 544, + 292 + ], + "type": "image", + "image_path": "fdb0fc6b3c5aa90f360f3ed8e90077714876203d9e3fca7d9f763c6e218ee714.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "lines": [ + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "spans": [ + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "text", + "content": "Figure 4. The overview of our framework. Besides content queries " + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}_0^c" + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "text", + "content": ", we also maintain a set of learnable position queries " + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}_0^p" + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "text", + "content": ". The content queries " + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}^c" + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "text", + "content": " aggregate features from the global features " + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "text", + "content": ". The position queries " + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}^p" + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "text", + "content": " are designed to guide the cross-attention. The attention weights are adjusted based on the relative positions between the position queries " + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}^p" + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "text", + "content": " and the global positions " + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "inline_equation", + "content": "\\mathcal{P}" + }, + { + "bbox": [ + 46, + 293, + 546, + 338 + ], + "type": "text", + "content": ". Both content and position queries are iteratively refined in each layer. Only 3 decoder layers are shown (we use 6 layers in our experiments)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 354, + 289, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 354, + 289, + 594 + ], + "spans": [ + { + "bbox": [ + 46, + 354, + 289, + 594 + ], + "type": "text", + "content": "cently, many works [16, 52, 53, 59, 58, 13, 15, 51, 66] rely on the self-attention in transformers to develop vision fundamental models. Besides, DETR [3] proposes a fully end-to-end pipeline for object detection. It utilizes transformer decoders to dynamically aggregate features from images, and uses one-to-one bipartite matching for ground-truth assignment, yielding an elegant pipeline. To solve the notorious slow convergence of DETR, approaches [76, 62, 41, 37, 70, 68] propose deformable attention, impose strong prior or decrease searching space in cross-attention to accelerate convergence. Further, methods of [29, 39, 22, 71, 30] present several ways to stabilize matching and training. Moreover, masked attention [8, 7] are proposed to impose semantic priors to accelerate training for segmentation tasks. Recently, there are works [28, 73, 63, 64, 43, 49, 50] that develop transformer models tailored for 3D point clouds. Following this line of research, we observe the low recall of initial instance masks, and present solutions to circumvent the use of mask attention." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 605, + 102, + 617 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 605, + 102, + 617 + ], + "spans": [ + { + "bbox": [ + 47, + 605, + 102, + 617 + ], + "type": "text", + "content": "3. Method" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 626, + 287, + 662 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 626, + 287, + 662 + ], + "spans": [ + { + "bbox": [ + 46, + 626, + 287, + 662 + ], + "type": "text", + "content": "We first review previous methods and present the overview of our method in Sec. 3.1. Then, we elaborate on the details of our position-aware designs in Sec. 3.2." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 670, + 115, + 681 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 670, + 115, + 681 + ], + "spans": [ + { + "bbox": [ + 47, + 670, + 115, + 681 + ], + "type": "text", + "content": "3.1. Overview" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 689, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 689, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 689, + 287, + 715 + ], + "type": "text", + "content": "Preliminary. Recently, Mask3D [49] and SPFormer [50] present a fully end-to-end pipeline, which allows the object" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 354, + 547, + 511 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 354, + 547, + 511 + ], + "spans": [ + { + "bbox": [ + 304, + 354, + 547, + 511 + ], + "type": "text", + "content": "queries to directly output instance predictions. With transformer decoders, a fixed number of object queries aggregate information from the global features (either multi-scale voxel features [49] or superpoint features [50]) extracted with the backbone. Moreover, similar to Mask2Former [8, 7], they adopt mask attention and rely on the instance masks to guide the cross-attention. Specifically, the cross-attention is masked with the instance masks predicted in the last decoder layer, so that the queries only need to consider the masked features. However, as shown in Fig. 3, the recall of initial instance masks is low in the early stages of training. It hinders the ability to achieve a high-quality result in the subsequent layers and thus increases training difficulty." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": "Ours. Instead of relying on mask attention, we propose an auxiliary center regression task to guide instance segmentation. The overview of our method is shown in Fig. 4 (a). We first yield the global positions " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{P} \\in \\mathbb{R}^{N \\times 3}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " from the input point cloud and extract the global features " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{F} \\in \\mathbb{R}^{N \\times d}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " using the backbone (" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{P}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " can be either voxels [49] or superpoints [50] positions and features). In contrast to existing works, besides the content queries " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}_0^c \\in \\mathbb{R}^{n \\times d}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": ", we also maintain a fixed number of position queries " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}_0^p \\in [0,1]^{n \\times 3}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " that represent the normalized instance centers. " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}_0^p" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " is randomly initialized and " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}_0^c" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " is initialized with zero. Given the global positions " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{P}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": " and global features " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": ", our goal is to let the positional queries guide their corresponding content queries in cross-attention, and then iteratively refine both sets of queries, and finally predict the instance centers, classes and masks. For the " + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 521, + 547, + 715 + ], + "type": "text", + "content": "-th decoder layer, this process" + } + ] + } + ], + "index": 8 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 758 + ], + "type": "text", + "content": "3695" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 70, + 286, + 159 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 286, + 159 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 286, + 159 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 286, + 159 + ], + "type": "image", + "image_path": "17ffc6992a3a51b10149207fa5653ca8cf33c708a4f6e2d6e69aa6ace5bc1633.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 163, + 287, + 186 + ], + "lines": [ + { + "bbox": [ + 47, + 163, + 287, + 186 + ], + "spans": [ + { + "bbox": [ + 47, + 163, + 287, + 186 + ], + "type": "text", + "content": "Figure 5. The illustration for relative position encoding. We note the shape of the corresponding tensor at the bottom." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 206, + 115, + 217 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 206, + 115, + 217 + ], + "spans": [ + { + "bbox": [ + 47, + 206, + 115, + 217 + ], + "type": "text", + "content": "is formulated as" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 86, + 228, + 287, + 243 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 86, + 228, + 287, + 243 + ], + "spans": [ + { + "bbox": [ + 86, + 228, + 287, + 243 + ], + "type": "interline_equation", + "content": "\\mathbf {C e n t e r} _ {t} = \\mathbf {M L P} _ {\\text {c e n t e r}} \\left(\\mathbf {Q} _ {t} ^ {c}\\right) + \\mathbf {Q} _ {t - 1} ^ {p}, \\tag {1}", + "image_path": "82a3b2ba0e42ccf56e0bcd659ac7ffbfb7c4f3d80c1e48ab38850c6d1bb7cbfc.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 115, + 263, + 287, + 277 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 115, + 263, + 287, + 277 + ], + "spans": [ + { + "bbox": [ + 115, + 263, + 287, + 277 + ], + "type": "interline_equation", + "content": "\\mathbf {C l a s s} _ {t} = \\mathbf {M L P} _ {c l s} \\left(\\mathbf {Q} _ {t} ^ {c}\\right), \\tag {2}", + "image_path": "b61b2335e402d605c52dbb2be5f3b99177f112c4212cf188a3499c240ecc1e45.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 303, + 294, + 327 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 303, + 294, + 327 + ], + "spans": [ + { + "bbox": [ + 47, + 303, + 294, + 327 + ], + "type": "interline_equation", + "content": "\\mathbf {M a s k} _ {t} = \\sigma \\left(\\mathbf {Q} _ {t} ^ {c} \\cdot \\mathcal {F} _ {\\text {m a s k}} ^ {T}\\right) < 0. 5, \\mathcal {F} _ {\\text {m a s k}} = \\mathbf {M L P} _ {\\text {m a s k}} (\\mathcal {F}), \\tag {3}", + "image_path": "82110441d6de0b9775757b450c7f2d1c5cb79c53e05937fd91c9c1998c2aeb55.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 328, + 287, + 364 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 328, + 287, + 364 + ], + "spans": [ + { + "bbox": [ + 47, + 328, + 287, + 364 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 328, + 287, + 364 + ], + "type": "inline_equation", + "content": "\\mathbf{Center}_t\\in \\mathbb{R}^{n\\times 3}" + }, + { + "bbox": [ + 47, + 328, + 287, + 364 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 328, + 287, + 364 + ], + "type": "inline_equation", + "content": "\\mathbf{Class}_t\\in \\mathbb{R}^{n\\times K}" + }, + { + "bbox": [ + 47, + 328, + 287, + 364 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 328, + 287, + 364 + ], + "type": "inline_equation", + "content": "\\mathbf{Mask}_t\\in \\{0,1\\}^{n\\times N}" + }, + { + "bbox": [ + 47, + 328, + 287, + 364 + ], + "type": "text", + "content": " are the predicted centers, classification logits, and the instance masks." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 372, + 178, + 385 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 372, + 178, + 385 + ], + "spans": [ + { + "bbox": [ + 47, + 372, + 178, + 385 + ], + "type": "text", + "content": "3.2. Position-aware Designs" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 391, + 287, + 427 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 391, + 287, + 427 + ], + "spans": [ + { + "bbox": [ + 47, + 391, + 287, + 427 + ], + "type": "text", + "content": "To effectively support the center regression task and improve the recall of initial instance masks, we propose a series of position-aware designs as follows." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 442, + 287, + 538 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 442, + 287, + 538 + ], + "spans": [ + { + "bbox": [ + 47, + 442, + 287, + 538 + ], + "type": "text", + "content": "Learnable Position Query. Unlike previous works [49, 50], we introduce an additional set of position queries " + }, + { + "bbox": [ + 47, + 442, + 287, + 538 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}_0^p\\in [0,1]^{n\\times 3}" + }, + { + "bbox": [ + 47, + 442, + 287, + 538 + ], + "type": "text", + "content": ". Since the range of points varies significantly among different scenes, the initial position queries are stored in a normalized form as learnable parameters followed by sigmoid function. Basically, we can obtain the absolute positions " + }, + { + "bbox": [ + 47, + 442, + 287, + 538 + ], + "type": "inline_equation", + "content": "\\hat{\\mathcal{Q}}_t^p\\in \\mathbb{R}^{n\\times 3}" + }, + { + "bbox": [ + 47, + 442, + 287, + 538 + ], + "type": "text", + "content": " from the normalized position queries " + }, + { + "bbox": [ + 47, + 442, + 287, + 538 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}_t^p" + }, + { + "bbox": [ + 47, + 442, + 287, + 538 + ], + "type": "text", + "content": " for a given input scene as" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 94, + 550, + 287, + 564 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 94, + 550, + 287, + 564 + ], + "spans": [ + { + "bbox": [ + 94, + 550, + 287, + 564 + ], + "type": "interline_equation", + "content": "\\hat {\\mathcal {Q}} _ {t} ^ {p} = \\mathcal {Q} _ {t} ^ {p} \\cdot \\left(p _ {\\max } - p _ {\\min }\\right) + p _ {\\min }, \\tag {4}", + "image_path": "d4a2ca32ec52f9f178fd7e1fd09d95bbc8754a17fdaed154bc2d78754ae0c60a.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 570, + 287, + 617 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 570, + 287, + 617 + ], + "spans": [ + { + "bbox": [ + 47, + 570, + 287, + 617 + ], + "type": "text", + "content": "where the " + }, + { + "bbox": [ + 47, + 570, + 287, + 617 + ], + "type": "inline_equation", + "content": "p_{min}, p_{max} \\in \\mathbb{R}^3" + }, + { + "bbox": [ + 47, + 570, + 287, + 617 + ], + "type": "text", + "content": " represent the minimum and maximum coordinates of the input scene, respectively. The resultant " + }, + { + "bbox": [ + 47, + 570, + 287, + 617 + ], + "type": "inline_equation", + "content": "\\hat{\\mathcal{Q}}_t^p" + }, + { + "bbox": [ + 47, + 570, + 287, + 617 + ], + "type": "text", + "content": " explicitly represents the positions of the corresponding content queries " + }, + { + "bbox": [ + 47, + 570, + 287, + 617 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}_t^c" + }, + { + "bbox": [ + 47, + 570, + 287, + 617 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 618, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 618, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 618, + 287, + 714 + ], + "type": "text", + "content": "It is notable that the initial position queries are densely spread throughout the 3D space. Also, every query aggregates features from its local region. This design choice makes it easier for the initial queries to capture the objects in a scene with a high recall, as shown in Fig. 3. It overcomes the low-recall issue caused by initial instance masks, and consequently reduces the training complexity of the subsequent layers." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 72, + 545, + 167 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 167 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 167 + ], + "type": "text", + "content": "Relative Position Encoding. Other than the absolute position encoding (e.g., Fourier or sine transformations), we also adopt contextual relative position encoding in crossattention. Inspired by [28], we first calculate the relative positions " + }, + { + "bbox": [ + 305, + 72, + 545, + 167 + ], + "type": "inline_equation", + "content": "\\mathbf{r} \\in \\mathbb{R}^{n \\times N \\times 3}" + }, + { + "bbox": [ + 305, + 72, + 545, + 167 + ], + "type": "text", + "content": " between the position queries " + }, + { + "bbox": [ + 305, + 72, + 545, + 167 + ], + "type": "inline_equation", + "content": "\\hat{\\mathcal{Q}}_t^p \\in \\mathbb{R}^{n \\times 3}" + }, + { + "bbox": [ + 305, + 72, + 545, + 167 + ], + "type": "text", + "content": " and the global positions " + }, + { + "bbox": [ + 305, + 72, + 545, + 167 + ], + "type": "inline_equation", + "content": "\\mathcal{P} \\in \\mathbb{R}^{N \\times 3}" + }, + { + "bbox": [ + 305, + 72, + 545, + 167 + ], + "type": "text", + "content": ", and quantize it into discrete integers " + }, + { + "bbox": [ + 305, + 72, + 545, + 167 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{r}} \\in \\mathbb{Z}^{n \\times N \\times 3}" + }, + { + "bbox": [ + 305, + 72, + 545, + 167 + ], + "type": "text", + "content": " as shown in Fig. 5. It is formulated as" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 361, + 173, + 545, + 195 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 361, + 173, + 545, + 195 + ], + "spans": [ + { + "bbox": [ + 361, + 173, + 545, + 195 + ], + "type": "interline_equation", + "content": "\\mathbf {r} = \\hat {\\mathcal {Q}} _ {t} ^ {p} - \\mathcal {P}, \\quad \\hat {\\mathbf {r}} = \\left\\lfloor \\frac {\\mathbf {r}}{s} \\right\\rfloor + \\frac {L}{2}, \\tag {5}", + "image_path": "72387dec23b2181235f1a9db275d4c65d6274cff99b89c48b5820832d1584d15.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 197, + 545, + 232 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 197, + 545, + 232 + ], + "spans": [ + { + "bbox": [ + 305, + 197, + 545, + 232 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 197, + 545, + 232 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 305, + 197, + 545, + 232 + ], + "type": "text", + "content": " denotes the quantization size, " + }, + { + "bbox": [ + 305, + 197, + 545, + 232 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 305, + 197, + 545, + 232 + ], + "type": "text", + "content": " denotes the length of position encoding table. We plus " + }, + { + "bbox": [ + 305, + 197, + 545, + 232 + ], + "type": "inline_equation", + "content": "\\frac{L}{2}" + }, + { + "bbox": [ + 305, + 197, + 545, + 232 + ], + "type": "text", + "content": " to ensure the discrete relative positions are non-negative." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 232, + 545, + 281 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 232, + 545, + 281 + ], + "spans": [ + { + "bbox": [ + 305, + 232, + 545, + 281 + ], + "type": "text", + "content": "Then, we use the discrete relative positions " + }, + { + "bbox": [ + 305, + 232, + 545, + 281 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{r}}" + }, + { + "bbox": [ + 305, + 232, + 545, + 281 + ], + "type": "text", + "content": " as indices to look up the corresponding position encoding tables " + }, + { + "bbox": [ + 305, + 232, + 545, + 281 + ], + "type": "inline_equation", + "content": "\\mathbf{t} \\in \\mathbb{R}^{3 \\times L \\times d}" + }, + { + "bbox": [ + 305, + 232, + 545, + 281 + ], + "type": "text", + "content": ", as illustrated in Fig. 5. Formally, the relative position encoding " + }, + { + "bbox": [ + 305, + 232, + 545, + 281 + ], + "type": "inline_equation", + "content": "\\mathbf{f}^{pos} \\in \\mathbb{R}^{n \\times N \\times d}" + }, + { + "bbox": [ + 305, + 232, + 545, + 281 + ], + "type": "text", + "content": " is yielded as" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 351, + 288, + 545, + 301 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 351, + 288, + 545, + 301 + ], + "spans": [ + { + "bbox": [ + 351, + 288, + 545, + 301 + ], + "type": "interline_equation", + "content": "\\mathbf {f} ^ {\\text {p o s}} = \\mathbf {t} [ 0, \\hat {\\mathbf {r}} _ {x} ] + \\mathbf {t} [ 1, \\hat {\\mathbf {r}} _ {y} ] + \\mathbf {t} [ 2, \\hat {\\mathbf {r}} _ {z} ], \\tag {6}", + "image_path": "1126cffe534ccb3364abb1466f9db6666baf72be501b2abc0ca7d11f6156777d.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 308, + 545, + 332 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 308, + 545, + 332 + ], + "spans": [ + { + "bbox": [ + 305, + 308, + 545, + 332 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 308, + 545, + 332 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{r}}_x, \\hat{\\mathbf{r}}_y, \\hat{\\mathbf{r}}_z \\in \\mathbb{Z}^{n \\times N}" + }, + { + "bbox": [ + 305, + 308, + 545, + 332 + ], + "type": "text", + "content": " are the discrete relative positions along the " + }, + { + "bbox": [ + 305, + 308, + 545, + 332 + ], + "type": "inline_equation", + "content": "x, y" + }, + { + "bbox": [ + 305, + 308, + 545, + 332 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 305, + 308, + 545, + 332 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 305, + 308, + 545, + 332 + ], + "type": "text", + "content": "-axis, respectively." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 305, + 333, + 545, + 368 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 333, + 545, + 368 + ], + "spans": [ + { + "bbox": [ + 305, + 333, + 545, + 368 + ], + "type": "text", + "content": "Further, the relative position encoding " + }, + { + "bbox": [ + 305, + 333, + 545, + 368 + ], + "type": "inline_equation", + "content": "\\mathbf{f}^{pos}" + }, + { + "bbox": [ + 305, + 333, + 545, + 368 + ], + "type": "text", + "content": " performs dot product with the query features " + }, + { + "bbox": [ + 305, + 333, + 545, + 368 + ], + "type": "inline_equation", + "content": "\\mathbf{f}^q\\in \\mathbb{R}^{n\\times d}" + }, + { + "bbox": [ + 305, + 333, + 545, + 368 + ], + "type": "text", + "content": " or key features " + }, + { + "bbox": [ + 305, + 333, + 545, + 368 + ], + "type": "inline_equation", + "content": "\\mathbf{f}^k\\in \\mathbb{R}^{N\\times d}" + }, + { + "bbox": [ + 305, + 333, + 545, + 368 + ], + "type": "text", + "content": " in the cross-attention, which is formulated as" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 351, + 375, + 545, + 392 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 351, + 375, + 545, + 392 + ], + "spans": [ + { + "bbox": [ + 351, + 375, + 545, + 392 + ], + "type": "interline_equation", + "content": "\\mathbf {p o s} _ {-} \\mathbf {b i a s} _ {i, j} = \\mathbf {f} _ {i, j} ^ {p o s} \\cdot \\mathbf {f} _ {i} ^ {q} + \\mathbf {f} _ {i, j} ^ {p o s} \\cdot \\mathbf {f} _ {j} ^ {k}, \\tag {7}", + "image_path": "06ab01d380eaca4137abcc9e7f22fbc615c99247f591ae14de858ca4631315d7.jpg" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 305, + 398, + 545, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 398, + 545, + 434 + ], + "spans": [ + { + "bbox": [ + 305, + 398, + 545, + 434 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 398, + 545, + 434 + ], + "type": "inline_equation", + "content": "\\text{pos\\_bias} \\in \\mathbb{R}^{n \\times N}" + }, + { + "bbox": [ + 305, + 398, + 545, + 434 + ], + "type": "text", + "content": " is the positional bias. It is then added to the cross-attention weights, followed by the softmax function, as shown in Fig. 4 (b)." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 434, + 545, + 542 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 434, + 545, + 542 + ], + "spans": [ + { + "bbox": [ + 304, + 434, + 545, + 542 + ], + "type": "text", + "content": "It is worth noting that the RPE offers a greater degree of flexibility and error-insensitivity, compared to mask attention. In essence, RPE can be likened to a soft mask that has the ability to adjust attention weights flexibly, instead of hard masking. Another advantage of RPE is that it integrates semantic information (e.g., object size and class) and thus can harvest local information selectively. This is accomplished by the interaction between the relative positions and the semantic features (i.e., " + }, + { + "bbox": [ + 304, + 434, + 545, + 542 + ], + "type": "inline_equation", + "content": "\\mathbf{f}^q" + }, + { + "bbox": [ + 304, + 434, + 545, + 542 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 434, + 545, + 542 + ], + "type": "inline_equation", + "content": "\\mathbf{f}^k" + }, + { + "bbox": [ + 304, + 434, + 545, + 542 + ], + "type": "text", + "content": ")." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 556, + 545, + 678 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 556, + 545, + 678 + ], + "spans": [ + { + "bbox": [ + 304, + 556, + 545, + 678 + ], + "type": "text", + "content": "Iterative Refinement. Since the content queries in our decoder layers are updated regularly, it is not optimal to maintain frozen position queries throughout the decoding process. Additionally, the initial position queries are static, so it is beneficial to adapt them to the specific input scene in the subsequent layers. To that end, we iteratively refine the position queries based on the content queries. Specifically, as shown in Fig. 4 (b), we leverage an MLP to predict a center offset " + }, + { + "bbox": [ + 304, + 556, + 545, + 678 + ], + "type": "inline_equation", + "content": "\\Delta p_{t}" + }, + { + "bbox": [ + 304, + 556, + 545, + 678 + ], + "type": "text", + "content": " from the updated content query " + }, + { + "bbox": [ + 304, + 556, + 545, + 678 + ], + "type": "inline_equation", + "content": "Q_{t + 1}^{c}" + }, + { + "bbox": [ + 304, + 556, + 545, + 678 + ], + "type": "text", + "content": ". We then add it to the previous position query " + }, + { + "bbox": [ + 304, + 556, + 545, + 678 + ], + "type": "inline_equation", + "content": "\\hat{Q}_t^p" + }, + { + "bbox": [ + 304, + 556, + 545, + 678 + ], + "type": "text", + "content": " as" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 368, + 685, + 545, + 704 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 368, + 685, + 545, + 704 + ], + "spans": [ + { + "bbox": [ + 368, + 685, + 545, + 704 + ], + "type": "interline_equation", + "content": "\\Delta p _ {t} = \\mathbf {M L P} _ {\\text {c e n t e r}} \\left(\\mathcal {Q} _ {t + 1} ^ {c}\\right), \\tag {8}", + "image_path": "d710d818e408a0de29d79d29667757f163179b5f6babfa091d1d52ebe4f87e52.jpg" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 369, + 701, + 449, + 715 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 369, + 701, + 449, + 715 + ], + "spans": [ + { + "bbox": [ + 369, + 701, + 449, + 715 + ], + "type": "interline_equation", + "content": "\\hat {\\mathcal {Q}} _ {t + 1} ^ {p} = \\hat {\\mathcal {Q}} _ {t} ^ {p} + \\Delta p _ {t}.", + "image_path": "c5a9cfaed91c65324e4217ea77a8f98587eb2350e600b831d279dd1858c19ad1.jpg" + } + ] + } + ], + "index": 25 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3696" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 133 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 133 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 133 + ], + "type": "text", + "content": "Center Matching & Loss. To eliminate the need for duplicate removal methods such as non-maximum suppression (NMS), bipartite matching is adopted during training. Existing works [49, 50] rely on semantic predictions and binary masks to match the ground truths." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 133, + 286, + 203 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 133, + 286, + 203 + ], + "spans": [ + { + "bbox": [ + 46, + 133, + 286, + 203 + ], + "type": "text", + "content": "In contrast, to support center regression, we also incorporate center distance in bipartite matching. Since we require the queries to only attend to a local region, it is critical to ensure that they only match with nearby ground-truth objects. To achieve this, we adapt the matching costs formulation as follows" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 75, + 210, + 195, + 224 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 75, + 210, + 195, + 224 + ], + "spans": [ + { + "bbox": [ + 75, + 210, + 195, + 224 + ], + "type": "interline_equation", + "content": "\\mathcal {C} _ {c l s} (k, \\hat {k}) = \\mathrm {C E} (\\mathbf {C l a s s} _ {k}, \\hat {k}),", + "image_path": "eb34c407d2807df1fb732553c5c73d8de8005bf99bc1dd42e29e4ba23789f255.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 72, + 228, + 233, + 242 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 72, + 228, + 233, + 242 + ], + "spans": [ + { + "bbox": [ + 72, + 228, + 233, + 242 + ], + "type": "interline_equation", + "content": "\\mathcal {C} _ {d i c e} (k, \\hat {k}) = \\operatorname {D I C E} (\\mathbf {M a s k} _ {k}, \\mathbf {M a s k} _ {\\hat {k}}),", + "image_path": "1c4c7758dfaccaad0a70111d6db89fffbbd013ef925a1d10215ee360aa14cc42.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 74, + 245, + 286, + 265 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 245, + 286, + 265 + ], + "spans": [ + { + "bbox": [ + 74, + 245, + 286, + 265 + ], + "type": "interline_equation", + "content": "\\mathcal {C} _ {b c e} (k, \\hat {k}) = \\operatorname {B C E} (\\mathbf {M a s k} _ {k}, \\mathbf {M a s k} _ {\\hat {k}}), \\tag {9}", + "image_path": "1d228e548df8963be188b5d0df9755e60b6d0f136d0904d0b54fb71b3fd1ddbe.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 63, + 262, + 260, + 310 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 262, + 260, + 310 + ], + "spans": [ + { + "bbox": [ + 63, + 262, + 260, + 310 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {C} _ {\\text {c e n t e r}} (k, \\hat {k}) = \\mathrm {L} _ {1} (\\mathbf {C e n t e r} _ {k}, \\mathbf {C e n t e r} _ {\\hat {k}}), \\\\ \\mathcal {C} (k, \\hat {k}) = \\lambda_ {c l s} \\mathcal {C} _ {c l s} (k, \\hat {k}) + \\lambda_ {d i c e} \\mathcal {C} _ {d i c e} (k, \\hat {k}) \\\\ + \\lambda_ {b c e} \\mathcal {C} _ {b c e} (k, \\hat {k}) + \\lambda_ {c e n t e r} \\mathcal {C} _ {c e n t e r} (k, \\hat {k}), \\\\ \\end{array}", + "image_path": "d7c2a44853bc4553164dbfb6753276c767ec463856b2d3a3b74fa997c2829b00.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 320, + 286, + 356 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 320, + 286, + 356 + ], + "spans": [ + { + "bbox": [ + 46, + 320, + 286, + 356 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 320, + 286, + 356 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 46, + 320, + 286, + 356 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 320, + 286, + 356 + ], + "type": "inline_equation", + "content": "\\hat{k}" + }, + { + "bbox": [ + 46, + 320, + 286, + 356 + ], + "type": "text", + "content": " denotes a predicted and ground-truth instance, respectively, " + }, + { + "bbox": [ + 46, + 320, + 286, + 356 + ], + "type": "inline_equation", + "content": "\\mathcal{C} \\in \\mathbb{R}^{n \\times n_{inst}}" + }, + { + "bbox": [ + 46, + 320, + 286, + 356 + ], + "type": "text", + "content": " denotes the matching cost matrix, and " + }, + { + "bbox": [ + 46, + 320, + 286, + 356 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 320, + 286, + 356 + ], + "type": "text", + "content": " denotes the cost weights." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 357, + 286, + 392 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 357, + 286, + 392 + ], + "spans": [ + { + "bbox": [ + 46, + 357, + 286, + 392 + ], + "type": "text", + "content": "The Hungarian Algorithm is then applied on " + }, + { + "bbox": [ + 46, + 357, + 286, + 392 + ], + "type": "inline_equation", + "content": "\\mathcal{C}" + }, + { + "bbox": [ + 46, + 357, + 286, + 392 + ], + "type": "text", + "content": " to yield the one-to-one matching result " + }, + { + "bbox": [ + 46, + 357, + 286, + 392 + ], + "type": "inline_equation", + "content": "\\hat{\\sigma} \\in \\mathbb{Z}^n" + }, + { + "bbox": [ + 46, + 357, + 286, + 392 + ], + "type": "text", + "content": ", which is followed by the loss function as" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 85, + 401, + 286, + 491 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 85, + 401, + 286, + 491 + ], + "spans": [ + { + "bbox": [ + 85, + 401, + 286, + 491 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\hat {\\sigma} = \\arg \\min _ {\\sigma : \\sigma_ {i} \\neq \\sigma_ {j}, \\forall i \\neq j} \\sum_ {i = 1} ^ {n} \\mathcal {C} (i, \\sigma_ {i}), \\\\ \\mathcal {L} = \\lambda_ {c l s} \\operatorname {C E} \\left(\\operatorname {C l a s s} _ {i}, \\hat {\\sigma} _ {i}\\right) \\tag {10} \\\\ + \\lambda_ {d i c e} D I C E (\\mathbf {M a s k} _ {i}, \\mathbf {M a s k} _ {\\sigma_ {i}}) \\\\ + \\lambda_ {b c e} \\operatorname {B C E} \\left(\\mathbf {M a s k} _ {i}, \\mathbf {M a s k} _ {\\hat {\\sigma} _ {i}}\\right) \\\\ + \\lambda_ {c e n t e r} L _ {1} \\left(\\text {C e n t e r} _ {i}, \\text {C e n t e r} _ {\\hat {\\sigma} _ {i}}\\right). \\\\ \\end{array}", + "image_path": "036f83a869cfb0af96d546a0754423c42cfb5eb116f2fcf22ab6aa8164170bd2.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 500, + 123, + 514 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 500, + 123, + 514 + ], + "spans": [ + { + "bbox": [ + 47, + 500, + 123, + 514 + ], + "type": "text", + "content": "4. Experiment" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 520, + 286, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 520, + 286, + 604 + ], + "spans": [ + { + "bbox": [ + 46, + 520, + 286, + 604 + ], + "type": "text", + "content": "This section first provides an overview of the experimental setup in Sec. 4.1. We then present the 3D instance segmentation results in Sec. 4.2. Additionally, we conduct an extensive ablation study in Sec. 4.3. Furthermore, we showcase the object detection results and visual comparisons in Sections 4.4 and 4.5, respectively. Code and models will be made publicly available." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 611, + 169, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 611, + 169, + 624 + ], + "spans": [ + { + "bbox": [ + 47, + 611, + 169, + 624 + ], + "type": "text", + "content": "4.1. Experimental Setting" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 629, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 286, + 712 + ], + "type": "text", + "content": "Network Architecture. For both ScanNetv2 [14] and ScanNet200 [47], we follow previous works [50, 25, 55, 5, 33] to use 5-layer U-Net as the backbone. The initial channel is set to 32. Unless otherwise specified, we use the coordinates and colors as the input features. We use 6 layers of Transformer decoders, where the head number is set to 8 and the hidden and feed-forward dimensions are set" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "type": "text", + "content": "to 256 and 1024, respectively. We adopt Fourier absolute position encoding with the temperature set to 10,000. The quantization size for RPE is set to " + }, + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "type": "inline_equation", + "content": "0.1\\mathrm{m}" + }, + { + "bbox": [ + 304, + 72, + 545, + 204 + ], + "type": "text", + "content": ", and the length of the RPE table is 48. Unless otherwise specified, we choose [50] as the baseline model, since it has achieved the best performance on ScanNetv2 val set so far. For the S3DIS [1] dataset, following Mask3D [49], we use Res16UNet34C [9] as the backbone and employ 4 decoders to attend to the coarsest four scales, and this is repeated 3 times with the shared parameters. The decoder hidden and feed-forward dimensions are set to 128 and 1024, respectively." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 218, + 545, + 254 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 218, + 545, + 254 + ], + "spans": [ + { + "bbox": [ + 304, + 218, + 545, + 254 + ], + "type": "text", + "content": "Datasets. We use the ScanNetv2 [14], ScanNet200 [47] and S3DIS [1] datasets for evaluation. All of them are challenging large-scale indoor scene datasets." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 255, + 545, + 348 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 255, + 545, + 348 + ], + "spans": [ + { + "bbox": [ + 304, + 255, + 545, + 348 + ], + "type": "text", + "content": "The ScanNetv2 dataset comprises 1201 scenes for training, and an additional 312 and 100 indoor scenes for validation and testing, respectively. The scenes are captured with RGB-D cameras and annotated with 20 semantic labels, 18 of which are instance classes. The ScanNet200 dataset adopts the same point cloud data, but it offers more diverse annotations, covering 200 classes, 198 of which are instance classes." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 350, + 545, + 398 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 350, + 545, + 398 + ], + "spans": [ + { + "bbox": [ + 304, + 350, + 545, + 398 + ], + "type": "text", + "content": "The S3DIS dataset contains 271 rooms in 6 areas of three buildings, and 13 semantic categories are annotated. Following previous works, the scenes in Area 5 are used for validation and the others are for training." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 412, + 545, + 592 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 412, + 545, + 592 + ], + "spans": [ + { + "bbox": [ + 304, + 412, + 545, + 592 + ], + "type": "text", + "content": "Implementation Details. We adopt one RTX 3090 GPU for training on ScanNet and ScanNet200, and one A100 GPU on S3DIS. Following previous works, we use AdamW [40] optimizer with the learning rate and weight decay set to 0.0001 and 0.05, respectively. We adopt poly scheduler on ScanNet and ScanNet200, and oncycle scheduler on S3DIS. The batch size is set to 4. For the weights of matching costs and losses, " + }, + { + "bbox": [ + 304, + 412, + 545, + 592 + ], + "type": "inline_equation", + "content": "(\\lambda_{cls}, \\lambda_{bce}, \\lambda_{dice}, \\lambda_{center})" + }, + { + "bbox": [ + 304, + 412, + 545, + 592 + ], + "type": "text", + "content": " are set to (0.5, 1.0, 1.0, 0.5) on ScanNet and ScanNet200, and (2.0, 5.0, 1.0, 0.5) on S3DIS. The voxel size is set to " + }, + { + "bbox": [ + 304, + 412, + 545, + 592 + ], + "type": "inline_equation", + "content": "0.02\\mathrm{m}" + }, + { + "bbox": [ + 304, + 412, + 545, + 592 + ], + "type": "text", + "content": ". We limit the points number up to 250,000. Otherwise, we crop the scene by cubic windows iteratively until the point number is lower than the limit. During inference, we select the top 100 instances with the highest scores and set the minimum points number per instance to 100." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 599, + 471, + 612 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 599, + 471, + 612 + ], + "spans": [ + { + "bbox": [ + 305, + 599, + 471, + 612 + ], + "type": "text", + "content": "4.2. Instance Segmentation Results" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": "ScanNetv2. We present the results of instance segmentation on both the ScanNetv2 test and val sets in Tables 1 and 2, respectively. Our method achieves a considerable increase in mAP compared to previous works, suggesting a superior ability to capture fine-grained details and produce high-quality instance segmentation. While Mask3D [49] slightly outperforms our model in terms of " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathrm{mAP}_{50}" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": ", it is worth noting that this is potentially due to their use of a" + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3697" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 71, + 548, + 252 + ], + "blocks": [ + { + "bbox": [ + 48, + 71, + 548, + 252 + ], + "lines": [ + { + "bbox": [ + 48, + 71, + 548, + 252 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 548, + 252 + ], + "type": "table", + "html": "
MethodmAP\\( \\mathrm{mAP}_{50} \\)bathbedbkshfcabinetchaircountercurtaindeskdoorotherpicturefridges. cur.sinksofatabletoiletwind.
3D-BoNet [2]25.348.851.932.425.113.734.53.141.96.916.213.15.220.233.814.730.130.365.117.8
MTML [26]28.240.257.738.018.210.743.00.142.25.717.916.27.022.951.116.149.131.365.016.2
GICN [38]34.163.858.037.134.419.846.95.256.49.321.221.212.734.753.720.652.532.972.924.1
3D-MPA [17]35.561.145.748.429.927.759.14.733.221.221.727.819.341.341.019.557.435.284.921.3
Dyco3D [20]39.564.164.251.844.725.966.65.025.116.623.136.223.233.153.522.958.743.885.031.7
PE [69]39.664.566.746.744.624.362.42.257.710.621.934.023.948.747.522.554.135.081.827.3
PointGroup [25]40.763.663.949.641.524.364.52.157.011.421.135.921.742.866.625.656.234.186.029.1
HAIS [5]45.769.970.456.145.736.467.34.654.719.430.842.628.845.471.126.256.343.488.934.4
OccuSeg [19]48.667.280.253.642.836.970.220.533.130.137.947.432.743.786.248.560.139.484.627.3
SoftGroup [55]50.476.166.757.937.238.169.47.267.730.338.753.131.958.275.431.864.349.290.738.8
SSTNet [33]50.669.873.854.949.731.669.317.837.719.833.046.357.651.585.749.463.745.794.329.0
SPFormer [50]54.977.074.564.048.439.573.931.156.633.546.849.255.547.874.743.671.254.089.334.3
Mask3D* [49]56.678.092.659.740.842.073.723.959.838.645.854.956.871.660.148.064.657.592.236.4
Ours57.877.477.864.952.044.976.125.358.439.153.047.261.749.979.547.374.554.896.037.4
\\( Ours^‡ \\)59.678.688.972.144.846.076.825.155.840.850.453.961.661.885.848.268.455.193.145.0
", + "image_path": "0c98aed4ea727396411b2029f81989d0e989517f0ec5091b0e2bdad15f01f5f8.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 49, + 295, + 285, + 487 + ], + "blocks": [ + { + "bbox": [ + 47, + 255, + 545, + 277 + ], + "lines": [ + { + "bbox": [ + 47, + 255, + 545, + 277 + ], + "spans": [ + { + "bbox": [ + 47, + 255, + 545, + 277 + ], + "type": "text", + "content": "Table 1. 3D instance segmentation results on ScanNet test set. * denotes using Res16UNet34C (twice as many parameters as ours) as the backbone. ‡ denotes using surface normal. Methods published before the submission deadline (03/08/2023) are listed." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 49, + 295, + 285, + 487 + ], + "lines": [ + { + "bbox": [ + 49, + 295, + 285, + 487 + ], + "spans": [ + { + "bbox": [ + 49, + 295, + 285, + 487 + ], + "type": "table", + "html": "
MethodmAP\\( \\mathrm{mAP}_{50} \\)
GSPN [67]19.337.8
MTML [26]20.340.2
3D-MPA [17]35.559.1
Dyco3D [20]35.457.6
PointGroup [25]34.856.7
MaskGroup [75]42.063.3
HAIS [5]43.564.1
OccuSeg [19]44.260.7
SoftGroup [55]46.067.6
SSTNet [33]49.464.3
SPFormer [50]56.373.9
Mask3D* [49]55.273.7
Ours58.475.9
\\( Ours^‡ \\)59.976.5
", + "image_path": "ffc69739bd4205690c578deee1ff20a77747665cd7f2a1c64f76a9cbce30631d.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 48, + 542, + 282, + 604 + ], + "blocks": [ + { + "bbox": [ + 47, + 498, + 286, + 532 + ], + "lines": [ + { + "bbox": [ + 47, + 498, + 286, + 532 + ], + "spans": [ + { + "bbox": [ + 47, + 498, + 286, + 532 + ], + "type": "text", + "content": "Table 2. 3D instance segmentation results on ScanNet val set. * denotes using Res16UNet34C (twice as many parameters as ours) as the backbone. ‡ denotes using surface normal." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 542, + 282, + 604 + ], + "lines": [ + { + "bbox": [ + 48, + 542, + 282, + 604 + ], + "spans": [ + { + "bbox": [ + 48, + 542, + 282, + 604 + ], + "type": "table", + "html": "
MethodmAP\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
\\( SPFormer^† \\)[50]25.233.839.6
\\( Mask3D* \\)[49]27.437.042.3
Ours29.238.243.3
", + "image_path": "5577de9bcfac08ae3f1c01f8a660f6bdc9fe5a39cf7351bd16c647e557619fe1.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 653, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 653, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 47, + 653, + 286, + 712 + ], + "type": "text", + "content": "stronger backbone (i.e., Res16UNet34C with twice as many parameters as ours) and DBSCAN post-processing. Despite this, our approach produces significantly better performance on the ScanNetv2 val set than Mask3D, as seen in Table 2." + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 309, + 295, + 544, + 403 + ], + "blocks": [ + { + "bbox": [ + 47, + 610, + 286, + 632 + ], + "lines": [ + { + "bbox": [ + 47, + 610, + 286, + 632 + ], + "spans": [ + { + "bbox": [ + 47, + 610, + 286, + 632 + ], + "type": "text", + "content": "Table 3. 3D instance segmentation results on ScanNet200 val set. " + }, + { + "bbox": [ + 47, + 610, + 286, + 632 + ], + "type": "inline_equation", + "content": "{}^{ \\dagger }" + }, + { + "bbox": [ + 47, + 610, + 286, + 632 + ], + "type": "text", + "content": " denotes reproduced results. * denotes using Res16UNet34C." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 309, + 295, + 544, + 403 + ], + "lines": [ + { + "bbox": [ + 309, + 295, + 544, + 403 + ], + "spans": [ + { + "bbox": [ + 309, + 295, + 544, + 403 + ], + "type": "table", + "html": "
Method\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
PointGroup [25]57.8-
MaskGroup [75]65.0-
SoftGroup [55]66.1-
SSTNet [33]59.3-
SPFormer [50]66.8-
Mask3D [49]68.475.2
Ours69.175.7
", + "image_path": "e9639cde441f92db7c8f6db4667f88c7e934096c4d1c5070edfb15c4aa9c34a1.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 411, + 522, + 423 + ], + "lines": [ + { + "bbox": [ + 306, + 411, + 522, + 423 + ], + "spans": [ + { + "bbox": [ + 306, + 411, + 522, + 423 + ], + "type": "text", + "content": "Table 4. 3D instance segmentation results on S3DIS Area5." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 442, + 545, + 539 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 442, + 545, + 539 + ], + "spans": [ + { + "bbox": [ + 304, + 442, + 545, + 539 + ], + "type": "text", + "content": "ScanNet200. Table 3 presents our comparison with previous state-of-the-art methods on the val set of ScanNet200. Our method achieves a significant improvement in comparison to the other methods. Consistent conclusion is also seen on this challenging dataset. It is important to note that previous works employ mask attention, while our approach does not. This verifies the success of our auxiliary center regression task in replacing mask attention." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 553, + 545, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 553, + 545, + 590 + ], + "spans": [ + { + "bbox": [ + 304, + 553, + 545, + 590 + ], + "type": "text", + "content": "S3DIS. As shown in Table 4, our method is evaluated on S3DIS Area5. Our approach outperforms previous works. This consistently shows the superiority of our method." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 596, + 400, + 609 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 596, + 400, + 609 + ], + "spans": [ + { + "bbox": [ + 306, + 596, + 400, + 609 + ], + "type": "text", + "content": "4.3. Ablation Study" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 615, + 545, + 639 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 615, + 545, + 639 + ], + "spans": [ + { + "bbox": [ + 306, + 615, + 545, + 639 + ], + "type": "text", + "content": "We conduct an extensive ablation study to verify each component of our method as follows." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "Learnable Position Query. The position query aims to provide an explicit center representation to the content query counterpart. Making it learnable intends to learn an optimal initial spatial distribution. We notice that some previous works [49, 42] adopt non-parametric initial queries," + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "3698" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 72, + 214, + 166 + ], + "blocks": [ + { + "bbox": [ + 50, + 72, + 214, + 166 + ], + "lines": [ + { + "bbox": [ + 50, + 72, + 214, + 166 + ], + "spans": [ + { + "bbox": [ + 50, + 72, + 214, + 166 + ], + "type": "image", + "image_path": "0edad6df79495ad3017dd380634cbb5ab028077c15896be3efbcaba7ed186299.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 174, + 165, + 186, + 174 + ], + "lines": [ + { + "bbox": [ + 174, + 165, + 186, + 174 + ], + "spans": [ + { + "bbox": [ + 174, + 165, + 186, + 174 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 215, + 72, + 296, + 166 + ], + "blocks": [ + { + "bbox": [ + 215, + 72, + 296, + 166 + ], + "lines": [ + { + "bbox": [ + 215, + 72, + 296, + 166 + ], + "spans": [ + { + "bbox": [ + 215, + 72, + 296, + 166 + ], + "type": "image", + "image_path": "0d64127831112475c83b6176a852b03bacd2d0459dc637cc5f5a5962cc559a76.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 178, + 547, + 234 + ], + "lines": [ + { + "bbox": [ + 46, + 178, + 547, + 234 + ], + "spans": [ + { + "bbox": [ + 46, + 178, + 547, + 234 + ], + "type": "text", + "content": "Figure 6. Spatial distribution of ground truths that are matched to the same query at different training iterations. (a): Baseline. (b): Ours. We randomly select 10 object queries and record their matched ground-truth instances in the early training. The three scatter plots for each method represent the center XYZ coordinates of their matched ground-truth instances at different training iterations (the scatter points for a query correspond to different training iterations). More visualization details are given in supplementary material. Our method manifests strong positional matching consistency among different training iterations." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 298, + 72, + 378, + 166 + ], + "blocks": [ + { + "bbox": [ + 298, + 72, + 378, + 166 + ], + "lines": [ + { + "bbox": [ + 298, + 72, + 378, + 166 + ], + "spans": [ + { + "bbox": [ + 298, + 72, + 378, + 166 + ], + "type": "image", + "image_path": "8abec5f17ba7e85a54a79f9db06931f258d6530af111400e265787719734ab24.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 380, + 72, + 460, + 166 + ], + "blocks": [ + { + "bbox": [ + 380, + 72, + 460, + 166 + ], + "lines": [ + { + "bbox": [ + 380, + 72, + 460, + 166 + ], + "spans": [ + { + "bbox": [ + 380, + 72, + 460, + 166 + ], + "type": "image", + "image_path": "5235d3b5118f3901a7cd038901c40dadcf3017a14e1f8e498621f0bf8dca2429.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 420, + 165, + 432, + 174 + ], + "lines": [ + { + "bbox": [ + 420, + 165, + 432, + 174 + ], + "spans": [ + { + "bbox": [ + 420, + 165, + 432, + 174 + ], + "type": "text", + "content": "(b)" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 462, + 72, + 542, + 166 + ], + "blocks": [ + { + "bbox": [ + 462, + 72, + 542, + 166 + ], + "lines": [ + { + "bbox": [ + 462, + 72, + 542, + 166 + ], + "spans": [ + { + "bbox": [ + 462, + 72, + 542, + 166 + ], + "type": "image", + "image_path": "11fdca9eaf78ef11465e9fb216714abf81dd8ef8dcefdde63bf7b9846c226b75.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 48, + 251, + 286, + 323 + ], + "blocks": [ + { + "bbox": [ + 48, + 251, + 286, + 323 + ], + "lines": [ + { + "bbox": [ + 48, + 251, + 286, + 323 + ], + "spans": [ + { + "bbox": [ + 48, + 251, + 286, + 323 + ], + "type": "table", + "html": "
PositionContentmAP\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
FPSzero57.374.984.2
FPSlearnable57.175.083.4
learnablelearnable58.175.484.3
learnablezero58.475.984.5
", + "image_path": "ad92cd41d5912be765c1f00d84a0264753ccdbcfde54f707213e560ac152ec67.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 48, + 361, + 287, + 434 + ], + "blocks": [ + { + "bbox": [ + 47, + 329, + 287, + 352 + ], + "lines": [ + { + "bbox": [ + 47, + 329, + 287, + 352 + ], + "spans": [ + { + "bbox": [ + 47, + 329, + 287, + 352 + ], + "type": "text", + "content": "Table 5. Ablation study on different initializations for position and content queries." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 361, + 287, + 434 + ], + "lines": [ + { + "bbox": [ + 48, + 361, + 287, + 434 + ], + "spans": [ + { + "bbox": [ + 48, + 361, + 287, + 434 + ], + "type": "table", + "html": "
Position EncodingmAP\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
No PE0.00.00.0
Fourier APE57.776.083.8
Content-conditioned APE58.075.784.3
RPE58.475.984.5
", + "image_path": "e5fb6759ef48436c1c40084a70b2ec171b0c38e2757b17cb6a02045e1cffcff6.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 49, + 463, + 286, + 539 + ], + "blocks": [ + { + "bbox": [ + 65, + 441, + 268, + 453 + ], + "lines": [ + { + "bbox": [ + 65, + 441, + 268, + 453 + ], + "spans": [ + { + "bbox": [ + 65, + 441, + 268, + 453 + ], + "type": "text", + "content": "Table 6. Ablation study on different position encodings." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 49, + 463, + 286, + 539 + ], + "lines": [ + { + "bbox": [ + 49, + 463, + 286, + 539 + ], + "spans": [ + { + "bbox": [ + 49, + 463, + 286, + 539 + ], + "type": "table", + "html": "
IDiter. refinecenter matchcenter lossmAP\\( \\mathrm{mAP}_{50} \\)\\( \\mathrm{mAP}_{25} \\)
1✓✓57.575.384.0
2✓✓56.774.884.1
3✓✓56.874.684.5
4✓56.474.783.7
5✓✓✓58.475.984.5
", + "image_path": "f760a98fdbf59285ff480e1919da46d06990cba2de64ee524dbb01d9e18a9165.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_body" + } + ], + "index": 12 + }, + { + "bbox": [ + 47, + 544, + 287, + 567 + ], + "lines": [ + { + "bbox": [ + 47, + 544, + 287, + 567 + ], + "spans": [ + { + "bbox": [ + 47, + 544, + 287, + 567 + ], + "type": "text", + "content": "Table 7. Ablation study on iterative refinement and center matching & loss." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 581, + 287, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 581, + 287, + 665 + ], + "spans": [ + { + "bbox": [ + 46, + 581, + 287, + 665 + ], + "type": "text", + "content": "where Furthest Point Sampling (FPS) is used to sample a number of points and transform them into position encodings via Fourier transformation followed by an MLP. We make comparisons in Table 5. The results show that learnable position query and zero-initialized content query perform best. A potential reason why 'FPS' lags behind 'learnable' is that the latter learns an optimal spatial distribution." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "content": "Moreover, to show the pattern of the learnable position query, we visualize the spatial distribution of center coordinates of the matched ground truths for a query in Fig. 6. It shows that each query consistently attends to a local region." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 253, + 545, + 408 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 253, + 545, + 408 + ], + "spans": [ + { + "bbox": [ + 304, + 253, + 545, + 408 + ], + "type": "text", + "content": "Relative Position Encoding. We compare various position encodings that are employed in previous works [49, 41], such as Fourier Absolute Position Encoding (APE) and the content query-conditioned APE. Specifically, the latter uses an MLP to project the content query into a " + }, + { + "bbox": [ + 304, + 253, + 545, + 408 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 304, + 253, + 545, + 408 + ], + "type": "text", + "content": "-dim diagonal matrix, which then transforms the original absolute position encoding into a new one. It incorporates semantic information into the position encoding but does not consider relative relation. As shown in Table 6, RPE outperforms the others, which implies that both semantic information and relative relation are beneficial. Also, we notice that if we do not apply any position encoding, the training corrupts. This shows that positional prior is crucial in our framework." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 422, + 545, + 482 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 422, + 545, + 482 + ], + "spans": [ + { + "bbox": [ + 304, + 422, + 545, + 482 + ], + "type": "text", + "content": "Iterative Refinement. We remove the iterative refinement and freeze the position query in all decoder layers, and we find that it causes a performance drop of " + }, + { + "bbox": [ + 304, + 422, + 545, + 482 + ], + "type": "inline_equation", + "content": "0.9\\%" + }, + { + "bbox": [ + 304, + 422, + 545, + 482 + ], + "type": "text", + "content": " mAP as shown in the first row of Table 7. This verifies the effectiveness of iterative refinement." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 497, + 545, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 497, + 545, + 628 + ], + "spans": [ + { + "bbox": [ + 304, + 497, + 545, + 628 + ], + "type": "text", + "content": "Center Matching & Loss. Moreover, to manifest the importance of center matching and center loss, we also conduct ablation studies in Table 7. We first remove the center matching and keep the center loss in the second row of the table, and we find that the performance drops by " + }, + { + "bbox": [ + 304, + 497, + 545, + 628 + ], + "type": "inline_equation", + "content": "1.7\\%" + }, + { + "bbox": [ + 304, + 497, + 545, + 628 + ], + "type": "text", + "content": " mAP. Then we keep the center matching and remove the center loss. The performance also decreases by " + }, + { + "bbox": [ + 304, + 497, + 545, + 628 + ], + "type": "inline_equation", + "content": "1.6\\%" + }, + { + "bbox": [ + 304, + 497, + 545, + 628 + ], + "type": "text", + "content": " mAP as shown in the 3-rd row. When both are absent, we observe an even larger performance drop " + }, + { + "bbox": [ + 304, + 497, + 545, + 628 + ], + "type": "inline_equation", + "content": "(2.0\\% \\mathrm{mAP})" + }, + { + "bbox": [ + 304, + 497, + 545, + 628 + ], + "type": "text", + "content": " in the 4-th row. The results reveal that both center matching and loss are important to our framework." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 306, + 635, + 444, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 635, + 444, + 647 + ], + "spans": [ + { + "bbox": [ + 306, + 635, + 444, + 647 + ], + "type": "text", + "content": "4.4. Object Detection Results" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "The instance predictions of instance segmentation can be easily transformed into bounding box predictions, by obtaining the minimum and maximum coordinates of the masked instances. We empirically find that the generated object detection results from the instance predictions work" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3699" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 69, + 542, + 403 + ], + "blocks": [ + { + "bbox": [ + 53, + 69, + 542, + 403 + ], + "lines": [ + { + "bbox": [ + 53, + 69, + 542, + 403 + ], + "spans": [ + { + "bbox": [ + 53, + 69, + 542, + 403 + ], + "type": "image", + "image_path": "aff190b6b9477aeeab9ba6519fdd0de0bfdbf48ee560fb2b20d10d5f0c6345d3.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 65, + 409, + 266, + 564 + ], + "blocks": [ + { + "bbox": [ + 65, + 409, + 266, + 564 + ], + "lines": [ + { + "bbox": [ + 65, + 409, + 266, + 564 + ], + "spans": [ + { + "bbox": [ + 65, + 409, + 266, + 564 + ], + "type": "table", + "html": "
Methodtaskbox mAP50box mAP25
VoteNet [44]det33.558.6
HGNet [4]det34.461.3
MLCVNet [65]det41.464.5
GSDN [18]det34.862.8
H3DNet [72]det48.167.2
3DETR [42]det47.065.0
Group-free [39]det52.869.1
RBGNet [57]det55.270.6
HyperDet3D [74]det57.270.9
FCAF3D [48]det57.371.5
CAGroup3D [56]det61.375.1
3D-MPA [17]inst49.264.2
Mask3D [49]inst56.270.2
Oursinst63.973.5
", + "image_path": "15f26af3227e222071d868efb4bcee83c2ccb9591443ad67ad93bba8bbdc9971.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 567, + 287, + 601 + ], + "lines": [ + { + "bbox": [ + 46, + 567, + 287, + 601 + ], + "spans": [ + { + "bbox": [ + 46, + 567, + 287, + 601 + ], + "type": "text", + "content": "Table 8. 3D object detection results on ScanNetv2. For methods designed for the instance segmentation task, the bounding boxes are generated by the instance mask predictions." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 611, + 287, + 660 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 611, + 287, + 660 + ], + "spans": [ + { + "bbox": [ + 46, + 611, + 287, + 660 + ], + "type": "text", + "content": "significantly better than previous methods tailored for 3D object detection in terms of " + }, + { + "bbox": [ + 46, + 611, + 287, + 660 + ], + "type": "inline_equation", + "content": "\\mathrm{mAP}_{50}" + }, + { + "bbox": [ + 46, + 611, + 287, + 660 + ], + "type": "text", + "content": ", as shown in Table 8. This finding also shows that our approach outputs high-quality instance segmentation results with fewer artifacts." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 670, + 160, + 683 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 670, + 160, + 683 + ], + "spans": [ + { + "bbox": [ + 47, + 670, + 160, + 683 + ], + "type": "text", + "content": "4.5. Visual Comparison" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 689, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 689, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 689, + 287, + 715 + ], + "type": "text", + "content": "We visually compare our approach with previous state-of-the-art methods in Fig. 7. More examples are given in" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 411, + 546, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 411, + 546, + 460 + ], + "spans": [ + { + "bbox": [ + 305, + 411, + 546, + 460 + ], + "type": "text", + "content": "the supplementary material. The visualizations demonstrate that our method tends to correctly recognize the classes of the instances. It implies that our approach is able to generate more high-quality instance segmentation results." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 473, + 378, + 486 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 473, + 378, + 486 + ], + "spans": [ + { + "bbox": [ + 306, + 473, + 378, + 486 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 495, + 546, + 638 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 495, + 546, + 638 + ], + "spans": [ + { + "bbox": [ + 304, + 495, + 546, + 638 + ], + "type": "text", + "content": "In this work, we have presented a mask-attention-free transformer for the 3D instance segmentation task. We first observe the issue of low-recall of the initial masks in existing works. It adds training difficulty and slows down convergence. We thus avoid using mask attention and instead propose an auxiliary center regression task to guide the cross-attention. To fit center regression, we develop a series of designs. A dense distribution of position queries is learned to yield a higher recall of the perceived instances. Also, relative position encoding and iterative refinement are designed to further boost the performance. Each component is verified to be effective." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 647, + 408, + 661 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 647, + 408, + 661 + ], + "spans": [ + { + "bbox": [ + 306, + 647, + 408, + 661 + ], + "type": "text", + "content": "Acknowledgements" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 666, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 666, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 666, + 546, + 713 + ], + "type": "text", + "content": "This work was supported in part by the Research Grants Council under the Areas of Excellence scheme grant AoE/E-601/22-R and Shenzhen Science and Technology Program KQTD20210811090149095." + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3700" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 133 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 133 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 133 + ], + "type": "text", + "content": "[1] Iro Armeni, Ozan Sener, Amir R. Zamir, Helen Jiang, Ioannis Brilakis, Martin Fischer, and Silvio Savarese. 3d semantic parsing of large-scale indoor spaces. In CVPR, 2016. 2, 5" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 137, + 286, + 179 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 137, + 286, + 179 + ], + "spans": [ + { + "bbox": [ + 53, + 137, + 286, + 179 + ], + "type": "text", + "content": "[2] Yang Bo, Wang Jianan, Clark Ronald, Hu Qingyong, Wang Sen, Markham Andrew, and Trigoni Niki. Learning object bounding boxes for 3d instance segmentation on point clouds. In NeurIPS, pages 6737-6746, 2019. 2, 6" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 182, + 286, + 214 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 182, + 286, + 214 + ], + "spans": [ + { + "bbox": [ + 53, + 182, + 286, + 214 + ], + "type": "text", + "content": "[3] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In ECCV, 2020. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 217, + 286, + 249 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 217, + 286, + 249 + ], + "spans": [ + { + "bbox": [ + 53, + 217, + 286, + 249 + ], + "type": "text", + "content": "[4] Jintai Chen, Biwen Lei, Qingyu Song, Haochao Ying, Danny Z Chen, and Jian Wu. A hierarchical graph network for 3d object detection on point clouds. In CVPR, 2020. 8" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 251, + 286, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 251, + 286, + 293 + ], + "spans": [ + { + "bbox": [ + 53, + 251, + 286, + 293 + ], + "type": "text", + "content": "[5] Shaoyu Chen, Jiemin Fang, Qian Zhang, Wenyu Liu, and Xinggang Wang. Hierarchical aggregation for 3d instance segmentation. In ICCV, pages 15467-15476, 2021. 1, 2, 5, 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 296, + 286, + 327 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 296, + 286, + 327 + ], + "spans": [ + { + "bbox": [ + 53, + 296, + 286, + 327 + ], + "type": "text", + "content": "[6] Yukang Chen, Yanwei Li, Xiangyu Zhang, Jian Sun, and Jiaya Jia. Focal sparse convolutional networks for 3d object detection. In CVPR, 2022. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 330, + 286, + 372 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 330, + 286, + 372 + ], + "spans": [ + { + "bbox": [ + 53, + 330, + 286, + 372 + ], + "type": "text", + "content": "[7] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In CVPR, 2022. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 375, + 286, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 375, + 286, + 407 + ], + "spans": [ + { + "bbox": [ + 53, + 375, + 286, + 407 + ], + "type": "text", + "content": "[8] Bowen Cheng, Alex Schwing, and Alexander Kirillov. Per-pixel classification is not all you need for semantic segmentation. NeurIPS, 2021. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 409, + 286, + 441 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 409, + 286, + 441 + ], + "spans": [ + { + "bbox": [ + 53, + 409, + 286, + 441 + ], + "type": "text", + "content": "[9] Christopher Choy, JunYoung Gwak, and Silvio Savarese. 4d spatio-temporal convnets: Minkowski convolutional neural networks. In CVPR, 2019. 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 444, + 286, + 485 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 444, + 286, + 485 + ], + "spans": [ + { + "bbox": [ + 48, + 444, + 286, + 485 + ], + "type": "text", + "content": "[10] Ruihang Chu, Yukang Chen, Tao Kong, Lu Qi, and Lei Li. Icm-3d: Instantiated category modeling for 3d instance segmentation. IEEE Robotics and Automation Letters, 7(1):57-64, 2021. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 489, + 286, + 531 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 489, + 286, + 531 + ], + "spans": [ + { + "bbox": [ + 48, + 489, + 286, + 531 + ], + "type": "text", + "content": "[11] Ruihang Chu, Zhengzhe Liu, Xiaqing Ye, Xiao Tan, Xiaojuan Qi, Chi-Wing Fu, and Jiaya Jia. Command-driven articulated object understanding and manipulation. In CVPR, 2023. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 534, + 286, + 576 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 534, + 286, + 576 + ], + "spans": [ + { + "bbox": [ + 48, + 534, + 286, + 576 + ], + "type": "text", + "content": "[12] Ruihang Chu, Xiaqing Ye, Zhengzhe Liu, Xiao Tan, Xiaojuan Qi, Chi-Wing Fu, and Jiaya Jia. Twist: Two-way inter-label self-training for semi-supervised 3d instance segmentation. In CVPR, 2022. 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 579, + 286, + 621 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 579, + 286, + 621 + ], + "spans": [ + { + "bbox": [ + 48, + 579, + 286, + 621 + ], + "type": "text", + "content": "[13] Xiangxiang Chu, Zhi Tian, Yuqing Wang, Bo Zhang, Haibing Ren, Xiaolin Wei, Huaxia Xia, and Chunhua Shen. Twins: Revisiting the design of spatial attention in vision transformers. arXiv:2104.13840, 2021. 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 624, + 286, + 666 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 624, + 286, + 666 + ], + "spans": [ + { + "bbox": [ + 48, + 624, + 286, + 666 + ], + "type": "text", + "content": "[14] Angela Dai, Angel X. Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In CVPR, 2017. 2, 5" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 670, + 286, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 286, + 712 + ], + "type": "text", + "content": "[15] Xiaoyi Dong, Jianmin Bao, Dongdong Chen, Weiming Zhang, Nenghai Yu, Lu Yuan, Dong Chen, and Baining Guo. Cswin transformer: A general vision transformer backbone with cross-shaped windows. arXiv:2107.00652, 2021. 3" + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 33, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 138 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 138 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 138 + ], + "type": "text", + "content": "[16] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. ICLR, 2021. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 140, + 545, + 183 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 140, + 545, + 183 + ], + "spans": [ + { + "bbox": [ + 307, + 140, + 545, + 183 + ], + "type": "text", + "content": "[17] Francis Engelmann, Martin Bokeloh, Alireza Fathi, Bastian Leibe, and Matthias Nießner. 3d-mpa: Multi-proposal aggregation for 3d semantic instance segmentation. In CVPR, pages 9031-9040, 2020. 2, 6, 8" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 185, + 545, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 185, + 545, + 217 + ], + "spans": [ + { + "bbox": [ + 307, + 185, + 545, + 217 + ], + "type": "text", + "content": "[18] JunYoung Gwak, Christopher Choy, and Silvio Savarese. Generative sparse detection networks for 3d single-shot object detection. In ECCV, 2020. 8" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 219, + 545, + 251 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 219, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 307, + 219, + 545, + 251 + ], + "type": "text", + "content": "[19] Lei Han, Tian Zheng, Lan Xu, and Lu Fang. Occuseg: Occupancy-aware 3d instance segmentation. In CVPR, pages 2940-2949, 2020. 2, 6" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 253, + 545, + 295 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 253, + 545, + 295 + ], + "spans": [ + { + "bbox": [ + 307, + 253, + 545, + 295 + ], + "type": "text", + "content": "[20] Tong He, Chunhua Shen, and Anton van den Hengel. Dyco3d: Robust instance segmentation of 3d point clouds through dynamic convolution. In CVPR, pages 354-363, 2021. 2, 6" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 297, + 545, + 329 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 297, + 545, + 329 + ], + "spans": [ + { + "bbox": [ + 307, + 297, + 545, + 329 + ], + "type": "text", + "content": "[21] Ji Hou, Angela Dai, and Matthias Nießner. 3d-sis: 3d semantic instance segmentation of rgb-d scans. In CVPR, pages 4421-4430, 2019. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 331, + 545, + 364 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 331, + 545, + 364 + ], + "spans": [ + { + "bbox": [ + 307, + 331, + 545, + 364 + ], + "type": "text", + "content": "[22] Ding Jia, Yuhui Yuan, Haodi He, Xiaopei Wu, Haojun Yu, Weihong Lin, Lei Sun, Chao Zhang, and Han Hu. Detrs with hybrid matching. arXiv preprint, 2022. 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 365, + 545, + 398 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 365, + 545, + 398 + ], + "spans": [ + { + "bbox": [ + 307, + 365, + 545, + 398 + ], + "type": "text", + "content": "[23] Haiyong Jiang, Feilong Yan, Jianfei Cai, Jianmin Zheng, and Jun Xiao. End-to-end 3d point cloud instance segmentation without detection. In CVPR, pages 12796-12805, 2020. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 399, + 545, + 442 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 399, + 545, + 442 + ], + "spans": [ + { + "bbox": [ + 307, + 399, + 545, + 442 + ], + "type": "text", + "content": "[24] Li Jiang, Shaoshuai Shi, Zhuotao Tian, Xin Lai, Shu Liu, Chi-Wing Fu, and Jiaya Jia. Guided point contrastive learning for semi-supervised point cloud semantic segmentation. In ICCV, 2021. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 445, + 545, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 445, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 307, + 445, + 545, + 487 + ], + "type": "text", + "content": "[25] Li Jiang, Hengshuang Zhao, Shaoshuai Shi, Shu Liu, ChiWing Fu, and Jiaya Jia. Pointgroup: Dual-set point grouping for 3d instance segmentation. In CVPR, pages 4867-4876, 2020. 1, 2, 5, 6" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 489, + 545, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 489, + 545, + 521 + ], + "spans": [ + { + "bbox": [ + 307, + 489, + 545, + 521 + ], + "type": "text", + "content": "[26] Jean Lahoud, Bernard Ghanem, Marc Pollefeys, and Martin R Oswald. 3d instance segmentation via multi-task metric learning. In ICCV, pages 9256-9266, 2019. 2, 6" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 523, + 545, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 523, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 307, + 523, + 545, + 555 + ], + "type": "text", + "content": "[27] Xin Lai, Yukang Chen, Fanbin Lu, Jianhui Liu, and Jiaya Jia. Spherical transformer for lidar-based 3d recognition. In CVPR, 2023. 2" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 557, + 545, + 599 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 557, + 545, + 599 + ], + "spans": [ + { + "bbox": [ + 307, + 557, + 545, + 599 + ], + "type": "text", + "content": "[28] Xin Lai, Jianhui Liu, Li Jiang, Liwei Wang, Hengshuang Zhao, Shu Liu, Xiaojuan Qi, and Jiaya Jia. Stratified transformer for 3d point cloud segmentation. In CVPR, 2022. 2, 3, 4" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 601, + 545, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 601, + 545, + 634 + ], + "spans": [ + { + "bbox": [ + 307, + 601, + 545, + 634 + ], + "type": "text", + "content": "[29] Feng Li, Hao Zhang, Shilong Liu, Jian Guo, Lionel M Ni, and Lei Zhang. Dn-detr: Accelerate detr training by introducing query denoising. In CVPR, 2022. 3" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 307, + 636, + 545, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 636, + 545, + 679 + ], + "spans": [ + { + "bbox": [ + 307, + 636, + 545, + 679 + ], + "type": "text", + "content": "[30] Feng Li, Hao Zhang, Shilong Liu, Lei Zhang, Lionel M Ni, Heung-Yeung Shum, et al. Mask dino: Towards a unified transformer-based framework for object detection and segmentation. arXiv preprint, 2022. 3" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 307, + 681, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 681, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 681, + 545, + 712 + ], + "type": "text", + "content": "[31] Yanwei Li, Yilun Chen, Xiaojuan Qi, Zeming Li, Jian Sun, and Jiaya Jia. Unifying voxel-based representation with transformer for 3d object detection. NeurIPS, 2022. 2" + } + ] + } + ], + "index": 32 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 314, + 757 + ], + "type": "text", + "content": "3701" + } + ] + } + ], + "index": 34 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 19, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 105 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 105 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 105 + ], + "type": "text", + "content": "[32] Yanwei Li, Xiaojuan Qi, Yukang Chen, Liwei Wang, Zeming Li, Jian Sun, and Jiaya Jia. Voxel field fusion for 3d object detection. In CVPR, 2022. 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 106, + 287, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 106, + 287, + 139 + ], + "spans": [ + { + "bbox": [ + 48, + 106, + 287, + 139 + ], + "type": "text", + "content": "[33] Zhihao Liang, Zhihao Li, Songcen Xu, Mingkui Tan, and Kui Jia. Instance segmentation in 3d scenes using semantic superpoint tree networks. In ICCV, 2021. 2, 5, 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 140, + 287, + 183 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 140, + 287, + 183 + ], + "spans": [ + { + "bbox": [ + 48, + 140, + 287, + 183 + ], + "type": "text", + "content": "[34] Jiahui Liu, Chirui Chang, Jianhui Liu, Xiaoyang Wu, Lan Ma, and Xiaojuan Qi. Mars3d: A plug-and-play motion-aware model for semantic segmentation on multi-scan 3d point clouds. In CVPR, 2023. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 184, + 287, + 216 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 184, + 287, + 216 + ], + "spans": [ + { + "bbox": [ + 48, + 184, + 287, + 216 + ], + "type": "text", + "content": "[35] Jianhui Liu, Yukang Chen, Xiaqing Ye, and Xiaojuan Qi. Prior-free category-level pose estimation with implicit space transformation. arXiv preprint arXiv:2303.13479, 2023. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 217, + 287, + 249 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 217, + 287, + 249 + ], + "spans": [ + { + "bbox": [ + 48, + 217, + 287, + 249 + ], + "type": "text", + "content": "[36] Jianhui Liu, Yukang Chen, Xiaqing Ye, Zhuotao Tian, Xiao Tan, and Xiaojuan Qi. Spatial pruned sparse convolution for efficient 3d object detection. NeurIPS, 2022. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 250, + 287, + 282 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 250, + 287, + 282 + ], + "spans": [ + { + "bbox": [ + 48, + 250, + 287, + 282 + ], + "type": "text", + "content": "[37] Shilong Liu, Feng Li, Hao Zhang, Xiao Yang, Xianbiao Qi, Hang Su, Jun Zhu, and Lei Zhang. Dab-detr: Dynamic anchor boxes are better queries for detr. In ICLR, 2022. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 283, + 287, + 316 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 283, + 287, + 316 + ], + "spans": [ + { + "bbox": [ + 48, + 283, + 287, + 316 + ], + "type": "text", + "content": "[38] Shih-Hung Liu, Shang-Yi Yu, Shao-Chi Wu, Hwann-Tzong Chen, and Tyng-Luh Liu. Learning gaussian instance segmentation in point clouds. arXiv preprint, 2020. 6" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 316, + 287, + 347 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 316, + 287, + 347 + ], + "spans": [ + { + "bbox": [ + 48, + 316, + 287, + 347 + ], + "type": "text", + "content": "[39] Ze Liu, Zheng Zhang, Yue Cao, Han Hu, and Xin Tong. Group-free 3d object detection via transformers. In ICCV, 2021. 3, 8" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 349, + 287, + 371 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 349, + 287, + 371 + ], + "spans": [ + { + "bbox": [ + 48, + 349, + 287, + 371 + ], + "type": "text", + "content": "[40] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. arXiv:1711.05101, 2017. 5" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 372, + 287, + 414 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 372, + 287, + 414 + ], + "spans": [ + { + "bbox": [ + 48, + 372, + 287, + 414 + ], + "type": "text", + "content": "[41] Depu Meng, Xiaokang Chen, Zejia Fan, Gang Zeng, Houqiang Li, Yuhui Yuan, Lei Sun, and Jingdong Wang. Conditional detr for fast training convergence. In ICCV, 2021. 3, 7" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 415, + 287, + 447 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 415, + 287, + 447 + ], + "spans": [ + { + "bbox": [ + 48, + 415, + 287, + 447 + ], + "type": "text", + "content": "[42] Ishan Misra, Rohit Girdhar, and Armand Joulin. An end-to-end transformer model for 3d object detection. In ICCV, 2021. 6, 8" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 449, + 287, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 449, + 287, + 470 + ], + "spans": [ + { + "bbox": [ + 48, + 449, + 287, + 470 + ], + "type": "text", + "content": "[43] Chunghyun Park, Yoonwoo Jeong, Minsu Cho, and Jaesik Park. Fast point transformer. In CVPR, 2022. 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 471, + 287, + 503 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 471, + 287, + 503 + ], + "spans": [ + { + "bbox": [ + 48, + 471, + 287, + 503 + ], + "type": "text", + "content": "[44] Charles R Qi, Or Litany, Kaiming He, and Leonidas J Guibas. Deep hough voting for 3d object detection in point clouds. In ICCV, 2019. 8" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 504, + 287, + 536 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 504, + 287, + 536 + ], + "spans": [ + { + "bbox": [ + 48, + 504, + 287, + 536 + ], + "type": "text", + "content": "[45] Charles R Qi, Hao Su, Kaichun Mo, and Leonidas J Guibas. Pointnet: Deep learning on point sets for 3d classification and segmentation. In CVPR, 2017. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 537, + 287, + 569 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 537, + 287, + 569 + ], + "spans": [ + { + "bbox": [ + 48, + 537, + 287, + 569 + ], + "type": "text", + "content": "[46] Charles Ruizhongtai Qi, Li Yi, Hao Su, and Leonidas J Guibas. Pointnet++: Deep hierarchical feature learning on point sets in a metric space. NeurIPS, 2017. 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 571, + 287, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 571, + 287, + 602 + ], + "spans": [ + { + "bbox": [ + 48, + 571, + 287, + 602 + ], + "type": "text", + "content": "[47] David Rozenberszki, Or Litany, and Angela Dai. Language-grounded indoor 3d semantic segmentation in the wild. In ECCV, 2022. 5" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 603, + 287, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 603, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 48, + 603, + 287, + 635 + ], + "type": "text", + "content": "[48] Danila Rukhovich, Anna Vorontsova, and Anton Konushin. Fcaf3d: fully convolutional anchor-free 3d object detection. In ECCV, 2022. 8" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 48, + 636, + 287, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 636, + 287, + 678 + ], + "spans": [ + { + "bbox": [ + 48, + 636, + 287, + 678 + ], + "type": "text", + "content": "[49] Jonas Schult, Francis Engelmann, Alexander Hermans, Or Litany, Siyu Tang, and Bastian Leibe. Mask3d for 3d semantic instance segmentation. ICRA, 2023. 1, 2, 3, 4, 5, 6, 7, 8" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 48, + 680, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 680, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 680, + 287, + 712 + ], + "type": "text", + "content": "[50] Jiahao Sun, Chunmei Qing, Junpeng Tan, and Xiangmin Xu. Superpoint transformer for 3d scene instance segmentation. AAAI, 2023. 1, 2, 3, 4, 5, 6" + } + ] + } + ], + "index": 18 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 72, + 545, + 714 + ], + "type": "list", + "angle": 0, + "index": 37, + "blocks": [ + { + "bbox": [ + 307, + 72, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 72, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 72, + 545, + 106 + ], + "type": "text", + "content": "[51] Shuyang Sun, Xiaoyu Yue, Song Bai, and Philip Torr. Visual parser: Representing part-whole hierarchies with transformers. arXiv:2107.05790, 2021. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "type": "text", + "content": "[52] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Herve Jegou. Training data-efficient image transformers & distillation through attention. In ICML, 2021. 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 152, + 545, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 184 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 184 + ], + "type": "text", + "content": "[53] Hugo Touvron, Matthieu Cord, Alexandre Sablayrolles, Gabriel Synnaeve, and Hervé Jégou. Going deeper with image transformers. arXiv:2103.17239, 2021. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 186, + 545, + 218 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 186, + 545, + 218 + ], + "spans": [ + { + "bbox": [ + 307, + 186, + 545, + 218 + ], + "type": "text", + "content": "[54] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In NeurIPS, 2017. 2" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 220, + 545, + 252 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 220, + 545, + 252 + ], + "spans": [ + { + "bbox": [ + 307, + 220, + 545, + 252 + ], + "type": "text", + "content": "[55] Thang Vu, Kookhoi Kim, Tung M Luu, Thanh Nguyen, and Chang D Yoo. Softgroup for 3d instance segmentation on point clouds. In CVPR, 2022. 1, 2, 5, 6" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 254, + 545, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 254, + 545, + 297 + ], + "spans": [ + { + "bbox": [ + 307, + 254, + 545, + 297 + ], + "type": "text", + "content": "[56] Haiyang Wang, Lihe Ding, Shaocong Dong, Shaoshuai Shi, Aoxue Li, Jianan Li, Zhenguo Li, and Liwei Wang. Cagroup3d: Class-aware grouping for 3d object detection on point clouds. In NeurIPS, 2022. 8" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 298, + 545, + 341 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 298, + 545, + 341 + ], + "spans": [ + { + "bbox": [ + 307, + 298, + 545, + 341 + ], + "type": "text", + "content": "[57] Haiyang Wang, Shaoshuai Shi, Ze Yang, Rongyao Fang, Qi Qian, Hongsheng Li, Bernt Schiele, and Liwei Wang. Rbgnet: Ray-based grouping for 3d object detection. In CVPR, 2022. 8" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 342, + 545, + 386 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 342, + 545, + 386 + ], + "spans": [ + { + "bbox": [ + 307, + 342, + 545, + 386 + ], + "type": "text", + "content": "[58] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pvtv2: Improved baselines with pyramid vision transformer. arXiv:2106.13797, 2021. 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 388, + 545, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 388, + 545, + 430 + ], + "spans": [ + { + "bbox": [ + 307, + 388, + 545, + 430 + ], + "type": "text", + "content": "[59] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In ICCV, 2021. 3" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 432, + 545, + 475 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 432, + 545, + 475 + ], + "spans": [ + { + "bbox": [ + 307, + 432, + 545, + 475 + ], + "type": "text", + "content": "[60] Weiyue Wang, Ronald Yu, Qiangui Huang, and Ulrich Neumann. Sgpn: Similarity group proposal network for 3d point cloud instance segmentation. In CVPR, pages 2569-2578, 2018. 2" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 477, + 545, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 477, + 545, + 510 + ], + "spans": [ + { + "bbox": [ + 307, + 477, + 545, + 510 + ], + "type": "text", + "content": "[61] Xinlong Wang, Shu Liu, Xiaoyong Shen, Chunhua Shen, and Jiaya Jia. Associatively segmenting instances and semantics in point clouds. In CVPR, pages 4096-4105, 2019. 2" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 307, + 511, + 545, + 543 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 511, + 545, + 543 + ], + "spans": [ + { + "bbox": [ + 307, + 511, + 545, + 543 + ], + "type": "text", + "content": "[62] Yingming Wang, Xiangyu Zhang, Tong Yang, and Jian Sun. Anchor detr: Query design for transformer-based detector. In AAAI, 2022. 3" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 307, + 544, + 545, + 577 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 544, + 545, + 577 + ], + "spans": [ + { + "bbox": [ + 307, + 544, + 545, + 577 + ], + "type": "text", + "content": "[63] Wenxuan Wu, Qi Shan, and Li Fuxin. Pointconvformer: Re-venge of the point-based convolution. arXiv preprint, 2022. 3" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 307, + 578, + 545, + 611 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 578, + 545, + 611 + ], + "spans": [ + { + "bbox": [ + 307, + 578, + 545, + 611 + ], + "type": "text", + "content": "[64] Xiaoyang Wu, Yixing Lao, Li Jiang, Xihui Liu, and Hengshuang Zhao. Point transformer v2: Grouped vector attention and partition-based pooling. NeurIPS, 2022. 3" + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 307, + 613, + 545, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 613, + 545, + 645 + ], + "spans": [ + { + "bbox": [ + 307, + 613, + 545, + 645 + ], + "type": "text", + "content": "[65] Qian Xie, Yu-Kun Lai, Jing Wu, Zhoutao Wang, Yiming Zhang, Kai Xu, and Jun Wang. Mlcvnet: Multi-level context votenet for 3d object detection. In CVPR, 2020. 8" + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 307, + 647, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 647, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 307, + 647, + 545, + 689 + ], + "type": "text", + "content": "[66] Jianwei Yang, Chunyuan Li, Pengchuan Zhang, Xiyang Dai, Bin Xiao, Lu Yuan, and Jianfeng Gao. Focal self-attention for local-global interactions in vision transformers. In NeurIPS, 2021. 3" + } + ] + } + ], + "index": 35 + }, + { + "bbox": [ + 307, + 691, + 545, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 691, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 307, + 691, + 545, + 714 + ], + "type": "text", + "content": "[67] Li Yi, Wang Zhao, He Wang, Minhyuk Sung, and Leonidas J Guibas. Gspn: Generative shape proposal network for 3d" + } + ] + } + ], + "index": 36 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3702" + } + ] + } + ], + "index": 38 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 399 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "type": "text", + "content": "instance segmentation in point cloud. In CVPR, pages 3947-3956, 2019. 2, 6" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 128 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 128 + ], + "type": "text", + "content": "[68] Qihang Yu, Huiyu Wang, Siyuan Qiao, Maxwell Collins, Yukun Zhu, Hartwig Adam, Alan Yuille, and Liang-Chieh Chen. k-means mask transformer. In ECCV, 2022. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 130, + 287, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 130, + 287, + 162 + ], + "spans": [ + { + "bbox": [ + 48, + 130, + 287, + 162 + ], + "type": "text", + "content": "[69] Biao Zhang and Peter Wonka. Point cloud instance segmentation using probabilistic embeddings. In CVPR, pages 8883-8892, 2021. 2, 6" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 164, + 287, + 196 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 164, + 287, + 196 + ], + "spans": [ + { + "bbox": [ + 48, + 164, + 287, + 196 + ], + "type": "text", + "content": "[70] Gongjie Zhang, Zhipeng Luo, Yingchen Yu, Kaiwen Cui, and Shijian Lu. Accelerating detr convergence via semantic-aligned matching. In CVPR, 2022. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 198, + 287, + 240 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 198, + 287, + 240 + ], + "spans": [ + { + "bbox": [ + 48, + 198, + 287, + 240 + ], + "type": "text", + "content": "[71] Hao Zhang, Feng Li, Shilong Liu, Lei Zhang, Hang Su, Jun Zhu, Lionel Ni, and Harry Shum. Dino: Detr with improved denoising anchor boxes for end-to-end object detection. In ICLR, 2022. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 243, + 287, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 243, + 287, + 274 + ], + "spans": [ + { + "bbox": [ + 48, + 243, + 287, + 274 + ], + "type": "text", + "content": "[72] Zaiwei Zhang, Bo Sun, Haitao Yang, and Qixing Huang. H3dnet: 3d object detection using hybrid geometric primitives. In ECCV, 2020. 8" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 277, + 287, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 277, + 287, + 297 + ], + "spans": [ + { + "bbox": [ + 48, + 277, + 287, + 297 + ], + "type": "text", + "content": "[73] Hengshuang Zhao, Li Jiang, Jiaya Jia, Philip HS Torr, and Vladlen Koltun. Point transformer. In ICCV, 2021. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 300, + 287, + 331 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 300, + 287, + 331 + ], + "spans": [ + { + "bbox": [ + 48, + 300, + 287, + 331 + ], + "type": "text", + "content": "[74] Yu Zheng, Yueqi Duan, Jiwen Lu, Jie Zhou, and Qi Tian. Hyperdet3d: Learning a scene-conditioned 3d object detector. In CVPR, 2022. 8" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 334, + 287, + 365 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 334, + 287, + 365 + ], + "spans": [ + { + "bbox": [ + 48, + 334, + 287, + 365 + ], + "type": "text", + "content": "[75] Min Zhong, Xinghao Chen, Xiaokang Chen, Gang Zeng, and Yunhe Wang. Maskgroup: Hierarchical point grouping and masking for 3d instance segmentation. In ICME, 2022. 1, 6" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 368, + 287, + 399 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 368, + 287, + 399 + ], + "spans": [ + { + "bbox": [ + 48, + 368, + 287, + 399 + ], + "type": "text", + "content": "[76] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable detr: Deformable transformers for end-to-end object detection. In ICLR, 2020. 3" + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3703" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Masked Autoencoders Are Stronger Knowledge Distillers/801459a1-6a61-45c0-b371-eb489abaf84f_content_list.json b/2023/Masked Autoencoders Are Stronger Knowledge Distillers/801459a1-6a61-45c0-b371-eb489abaf84f_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..2f44adf6a53f709896e69c6a5f5ca93ba659f3b8 --- /dev/null +++ b/2023/Masked Autoencoders Are Stronger Knowledge Distillers/801459a1-6a61-45c0-b371-eb489abaf84f_content_list.json @@ -0,0 +1,1550 @@ +[ + { + "type": "text", + "text": "Masked Autoencoders Are Stronger Knowledge Distillers", + "text_level": 1, + "bbox": [ + 194, + 130, + 774, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Shanshan Lao1* Guanglu Song2 Boxiao Liu2 Yu Liu2† Yujiu Yang1† \n1Tsinghua Shenzhen International Graduate School, Tsinghua University \n2Sensetime Research", + "bbox": [ + 194, + 178, + 776, + 232 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "laoss21@mails.tsinghua.edu.cn, {songguanglu, liuboxiao}@sensetime.com \nliuyuisanai@gmail.com, yang.yujiu@sz.tsinghua.edu.cn", + "bbox": [ + 178, + 236, + 790, + 268 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 304, + 313, + 319 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Knowledge distillation (KD) has shown great success in improving student's performance by mimicking the intermediate output of the high-capacity teacher in fine-grained visual tasks, e.g. object detection. This paper proposes a technique called Masked Knowledge Distillation (MKD) that enhances this process using a masked autoencoding scheme. In MKD, random patches of the input image are masked, and the corresponding missing feature is recovered by forcing it to imitate the output of the teacher. MKD is based on two core designs. First, using the student as the encoder, we develop an adaptive decoder architecture, which includes a spatial alignment module that operates on the multi-scale features in the feature pyramid network (FPN) [20], a simple decoder, and a spatial recovery module that mimics the teacher's output from the latent representation and mask tokens. Second, we introduce the masked convolution in each convolution block to keep the masked patches unaffected by others. By coupling these two designs, we can further improve the completeness and effectiveness of teacher knowledge learning. We conduct extensive experiments on different architectures with object detection and semantic segmentation. The results show that all the students can achieve further improvements compared to the conventional KD. Notably, we establish the new state-of-the-art results by boosting RetinaNet ResNet-18, and ResNet-50 from 33.4 to 37.5 mAP, and 37.4 to 41.5 mAP, respectively.", + "bbox": [ + 76, + 337, + 473, + 744 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 750, + 209, + 766 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "As fundamental tasks in computer vision, high-level visual predictions such as object detection, instance segmentation, and semantic segmentation have been widely used in various practical applications. In real-world scenarios, improving the performance of the deployable models is crucial. Improving the performance of a lightweight student", + "bbox": [ + 75, + 771, + 468, + 863 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/88c66b86dd6bd0d387cdbabb322d17a69d9b36027f56cbeee3ebeeb953888f8e.jpg", + "image_caption": [ + "Input Image", + "Figure 1: Visualization of feature maps of teacher networks (RetinaNet-ResX101) and student networks (RetinaNet-Res50) with different KD paradigms." + ], + "image_footnote": [], + "bbox": [ + 503, + 303, + 580, + 424 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/0f1ac6b509eb7a948d9e1dad720f961107c1e4098c9605be533391c8848f0151.jpg", + "image_caption": [ + "Feature of teacher" + ], + "image_footnote": [], + "bbox": [ + 581, + 303, + 656, + 424 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/a8e5b2815d34bff0f4d0a8538dc29e833d15108fa431957da5cad3ad9c563c63.jpg", + "image_caption": [ + "FitNet" + ], + "image_footnote": [], + "bbox": [ + 658, + 303, + 733, + 424 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/62441c15f3864316b7ba3c9744c673472da610a1c280fa5c92a8dad9e53acadd.jpg", + "image_caption": [ + "FGD" + ], + "image_footnote": [], + "bbox": [ + 733, + 303, + 810, + 424 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/b60be4c24b36845f929a341bb6704d967209689e0ae6fb4aafbf280ffe4a2e4b.jpg", + "image_caption": [ + "MKD" + ], + "image_footnote": [], + "bbox": [ + 810, + 303, + 888, + 424 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "model via a high-capacity teacher introduces an effective paradigm, which is widely known as Knowledge Distillation (KD) [16, 4]. For dense visual prediction tasks, feature-based distillation [17, 7, 11] is more beneficial for the student to mimic the teacher's intermediate features. Some elaborated feature-based distillation methods [29, 4, 40, 18] have established the state-of-the-art performance for many lightweight models such as ResNet-18 [15].", + "bbox": [ + 496, + 502, + 892, + 625 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The core bottleneck of such feature-based KD is how to learn the complete knowledge from the teacher's output containing about 20K spatial coordinates (calculated on the COCO training set). According to our experiment, $72\\%$ of them are simple enough and converge quickly to achieve $\\sim 90\\%$ similarity with the teacher's output. The remaining important knowledge is suppressed by this large number of simple samples, and it is difficult for the student to learn effectively. To further verify the existence of information redundancy in teacher features, we conduct experiments that, when $30\\%$ of the features are randomly masked during training and testing on Retina-R101 (38.4 mAP), it still achieved similar performance (38.1 mAP). Previous works [34, 46] point out similar observations that each pixel contributes equally if using a common distillation loss (e.g. MSE), which will cause the network to easily learn a lot of similar information and is hard to identify important information. So they use attention [45, 40] and decouple the", + "bbox": [ + 496, + 628, + 893, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Work done during internship at SenseTime Research.", + "bbox": [ + 94, + 875, + 382, + 887 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "† Corresponding authors.", + "bbox": [ + 96, + 887, + 225, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "6384", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "foreground and background feature [34, 46] to help alleviate this problem. But attention can still lead to the imbalance of information learning.", + "bbox": [ + 75, + 90, + 468, + 136 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In order to learn the complete information without being affected by the spatial redundancy in teacher features, we introduce the Mask Image Modeling (MIM) mechanism to effectively promote the learning of this information. To be more specific, we propose a new Masked Knowledge Distillation (MKD) framework to improve the knowledge learning of the student via the masked autoencoding paradigm. The core idea is that we mask random patches of the input image of the student while maintaining the whole input image for the teacher, and then recover the corresponding missing feature by forcing the student to imitate the output of the teacher. In this way, the student network is encouraged to predict the masked patches with corrupted input images and learn the relationship between the masked area and its surrounding regions, rather than simply imitating the output feature of the teacher at visible patches. We conduct some experiments trying to excavate the potential ability of the students. As shown in Fig. 1, according to the feature comparison in the red box, it can be observed that student network using MKD learns more complete knowledge from teacher than the direct feature-based method [1] and the attention-based method [40].", + "bbox": [ + 75, + 138, + 470, + 472 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We introduce two crucial designs to alleviate some bottlenecks in this framework. First, due to the masked image input, directly applying the normal convolution in the convolutional neural networks (CNN) will confuse the latent representation in visible and invisible patches. Therefore, we adopt the masked convolution [10, 23] to keep the masked patches not affected by others in each convolution block. Second, multi-scale features are often used in fine-grained high-level visual tasks which have different masked sizes, leading to inconsistent feature reconstruction. We developed an adaptive decoder architecture for this problem to predict the teacher's feature in the corresponding masked area. More specifically, a spatial alignment module is first operated on the multi-scale features to align them to the same spatial resolution. A mask token is then replicated multiple times to replace the features in the masked area. The features in the visible patches and mask tokens are sent to an adaptive transformer decoder to reconstruct the teacher's feature. Finally, we conduct the spatial recovery module to convert the same spatial resolution to the original multi-scale resolution to perform feature-based distillation.", + "bbox": [ + 75, + 474, + 470, + 792 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In our method, by the mask autoencoding paradigm with asymmetric input for student and teacher, the student is forced to infer the teacher's features in the invisible patches by imitating the teacher's features in the visible patches. We observe that the mask tokens in the decoder try to absorb knowledge from their adjacent region to restore the features in the masked region. Completely restoring the masked fea", + "bbox": [ + 75, + 795, + 468, + 902 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/94053f2caded8635b717900e1f8436c3fe8470fbab8920adc72b24e9b2a22953.jpg", + "image_caption": [ + "Figure 2: The average L2 distance between student's feature and teacher's feature calculated at the unmasked areas with RetinaNet-ResX101 distilling RetinaNet-Res50." + ], + "image_footnote": [], + "bbox": [ + 557, + 107, + 818, + 258 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "tures drives it to fully learn the teacher's corresponding information in these adjacent areas. As shown in Fig. 2, the L2 distance value in adjacent regions of the mask can be lower with masked input. This verifies the claim that the student network can better learn the teacher's knowledge in our learning manner. MKD can be directly used in different architectures and various dense visual prediction tasks, e.g., object detection and semantic segmentation. The results show that MKD can improve considerably cooperated with conventional feature-based distillation. For instance, with MKD in RetinaNet, the mAP of student ResNet-18 is greatly improved to 37.5, $4.1\\%$ higher than the baseline, and also outperforms the previous SOTA methods. To sum up, our contributions are as follows:", + "bbox": [ + 496, + 321, + 890, + 532 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose a new paradigm for feature-based distillation named MKD, using mask autoencoding scheme to effectively learn the complete knowledge in the teacher network. MKD masks random patches of the input image and recovers the corresponding masked feature by forcing it to imitate the teacher's output.", + "- We introduce the masked convolution and adaptive decoder module in MKD to make it easy to cooperate with different architectures in fine-grained visual tasks, e.g., object detection and semantic segmentation.", + "- Extensive experiments on various models and tasks verify the effectiveness of our method. For different student architectures and tasks, MKD can further improve the performance of feature-based distillation and establish new state-of-the-art." + ], + "bbox": [ + 517, + 536, + 890, + 780 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Works", + "text_level": 1, + "bbox": [ + 500, + 792, + 650, + 806 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Object Detection", + "text_level": 1, + "bbox": [ + 500, + 816, + 666, + 833 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "As a fundamental and challenging task in computer vision, object detection aims to detect the visual objects of a certain class in the images. Modern object detectors can be broadly divided into three paradigms: two-", + "bbox": [ + 498, + 840, + 890, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "6385", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/e72b0469a43ed8ae8380105c960dd74dd1732ec208415998e15297a9c14380de.jpg", + "image_caption": [ + "Figure 3: Illustration of the MKD. For clear visualization, we omit the original task losses, such as classification and localization loss. In this learning process, the parameter of the teacher is fixed. The mask token and decoder are not shared between different-scale features in FPN due to the semantic gap in different-scale features." + ], + "image_footnote": [], + "bbox": [ + 98, + 88, + 563, + 349 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/0f7c45bab01ba00024ba3ecee519c31078749cc7c5df8de41862d717ee394340.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 571, + 101, + 874, + 347 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "stage [28, 14, 35], anchor-based one-stage [21, 32, 24], and anchor-free one-stage [43, 9]. While detectors with strong backbones have better accuracy, they are computationally expensive and difficult to deploy on mobile devices. One interesting direction of research is the compression of detection networks, including quantization [36, 19], pruning [12, 38], and the design of lightweight networks [31]. In addition, Knowledge Distillation (KD) [16, 46, 37], has become an important method for transferring knowledge from larger, better-performing networks without changing the structure of the network.", + "bbox": [ + 75, + 412, + 472, + 580 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Knowledge Distillation for Detection", + "text_level": 1, + "bbox": [ + 76, + 590, + 393, + 606 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Knowledge distillation is a model compression and acceleration method that can transfer knowledge from the teacher model to the student model. The logit-based distillation methods [16, 46, 44] in classification are limited for the improvement of the fine-grained visual understanding tasks because the localization information from the teacher is crucial. Therefore, feature-based distillation over multiscale features has become the main method of distillation for detectors. Current feature distillation methods for detectors can be divided into the following four categories: (1) hint-based, (2) attention-based, (3) instance-based, and (4) masked-feature based. Hint-based methods [29, 1, 33, 42] take features from the intermediate layers as hints to guide the student model. However, such methods treat all regions equally and do not get satisfactory results. Instance-based methods aim to find the key instance regions for distillation by GT boxes or specifically designed modules, e.g. FGFI [34], GID [7], ICD [17]. Attention-based methods further improve the performance by using attention maps to", + "bbox": [ + 75, + 613, + 472, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "locate discriminative areas, e.g. FKD [45], FGD [40]. Recent work MGD [41] first proposed to mask out the feature maps in the knowledge distillation branch and use a generator to restore the teacher feature. In our work, we mask random patches of the original images and adopt masked convolution into the backbone network to prevent information leakage. This new paradigm introduces masks throughout the backbone network, enhancing the corresponding knowledge learning in adjacent regions of the random mask. Experiments have shown that distillation benefits well from the masking scheme, especially for longer schedules.", + "bbox": [ + 496, + 412, + 893, + 580 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Approach", + "text_level": 1, + "bbox": [ + 500, + 594, + 609, + 611 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Masked Knowledge Distillation", + "text_level": 1, + "bbox": [ + 500, + 618, + 777, + 635 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We first elaborate on the overall pipeline of our masked knowledge distillation (MKD) by instantiating an example in object detection. Let $F^{S} \\in \\mathbb{R}^{C \\times H \\times W}$ and $F^{T} \\in \\mathbb{R}^{C \\times H \\times W}$ denote the output features of student's FPN and teacher's FPN, respectively. The standard feature-based distillation can be formulated as:", + "bbox": [ + 496, + 642, + 893, + 734 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {f e a t}} = \\frac {1}{2 N} \\sum_ {i = 0} ^ {\\mathcal {P}} \\left(F _ {i} ^ {T} - \\phi \\left(F _ {i} ^ {S}\\right)\\right) ^ {2}, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 563, + 742, + 890, + 785 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\mathcal{P}$ indicates the total number of features in FPN and $\\mathrm{N} = \\mathrm{C_iH_iW_i}$ . $C_i, H_i, W_i$ represent the channel number, height, and width for feature map $F_{i}^{*}$ . $\\phi$ is a convolutional layer with kernel size $1\\times 1$ to align the channel dimension between the $F^T$ and $F^{S}$ .", + "bbox": [ + 496, + 794, + 890, + 868 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "As discussed above, to further enhance KD distillation dense visual predictions, we introduce the masked autoen", + "bbox": [ + 498, + 869, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "6386", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "coding scheme into KD learning. In this manner, the distillation of the features can be formulated as:", + "bbox": [ + 75, + 90, + 468, + 119 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {f e a t}} = \\frac {1}{2 N} \\sum_ {i = 0} ^ {\\mathcal {P}} \\left(F _ {i} ^ {T} - f _ {\\text {d e c}} \\left(\\phi \\left(F _ {i} ^ {S}\\right), \\mathcal {T} _ {\\text {m a s k}}\\right)\\right) ^ {2}, \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 96, + 128, + 468, + 169 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $f_{dec}$ is the proposed adaptive decoder module with spatial alignment module, stacked transformer decoder layers, and spatial recovery module. $T_{mask}$ is the mask token.", + "bbox": [ + 75, + 179, + 468, + 224 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The overall architecture of MKD is shown in Fig. 3. Firstly, given an image with $H \\times W$ , a binary mask map $\\mathcal{M}$ with the element number $N = \\frac{H}{s} \\times \\frac{W}{s}$ is randomly sampled with a given masking ratio. $s$ is the down-sampled factor of the mask map and we set it to 32 in our experiments. We progressively upsample the mask to align its resolution to the output of each convolutional stage in the student's backbone. Using the student as an encoder, the masked images are then sent to it and the masked residual blocks in each masked convolutional stage are conducted to leave the masked area unprocessed by the backbone in the forward process. Finally, the masked feature maps generated by FPN will be sent to an adaptive decoder module where a spatial alignment module (SAM) is introduced to operate on the multi-scale features, along with a decoder and spatial recovery module (SRM) that reconstructs the latent representations with mask tokens. This learning manner is supervised by forcing the student's output of the adaptive decoder to imitate the teacher's output. Even if we mask random patches of the input image, with the assistance of MKD, the student model can still infer the features of the invisible patches.", + "bbox": [ + 75, + 224, + 470, + 556 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.1.1 Masking in the Image Space.", + "text_level": 1, + "bbox": [ + 76, + 574, + 331, + 589 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Following ViT [8] and MAE [13], we first divide the input image into regular non-overlapping image patches, and then randomly generate a binary mask according to the given masking ratio. The masked area in the input image keeps unseen to the student model. We simply refer to this as \"random masking\". Notice that the random masking strategy follows a uniform distribution, which eliminates the potential center bias. The mask is illustrated in Fig. 3, which is a schematic gram, and the real masked image is shown in Fig. 1. Different from ViT, the convolutional neural network is designed with a pyramid scheme where different convolutional stages are set with different stride factors. This leads to multiple different spatial resolutions in the student's forward propagation. To make consistent with this, after generating a mask with resolution $\\frac{H}{32} \\times \\frac{W}{32}$ for the late stage in the student, we progressively upsample the mask to larger resolutions in early convolutional stages as shown in Fig. 3. Introducing random masking to knowledge distillation can create a task that cannot be easily solved by directly performing the pixel-to-pixel spatial matching supervision.", + "bbox": [ + 75, + 598, + 468, + 900 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/44507fda4160f07bd9321217b78f1c75f3186daed15c9449973a754a61149cc2.jpg", + "image_caption": [ + "Figure 4: Illustration of the adaptive decoder. The inputs are the corresponding mask and feature maps from the teacher's FPN and the student's FPN." + ], + "image_footnote": [], + "bbox": [ + 531, + 88, + 864, + 378 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.1.2 Masked Encoder.", + "text_level": 1, + "bbox": [ + 500, + 446, + 671, + 459 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In our MKD, the student backbone is used as the encoder to process the masked input image. To ensure that the network only operates on the visible patches and reconstructs only from the neighboring ones, previously masked auto-encoders such as MAE proposed to forward only the visible tokens into the encoder. However, this method cannot be used directly in convolutional networks since we need to preserve the spatial dimension of the image. Following ConvMAE [10], we adopt the masked convolution to solve this problem, which is commonly used in image inpainting [23] and sparse feature extraction [27] to process the incomplete input information. More specifically, masked convolutions are used in all blocks for each stage in the whole student so that the masked regions are not involved in the encoding process. The operation of masked convolution is shown in Fig. 3, where the input feature maps from the previous layer are masked firstly by performing the Hadamard product with the mask map. This can effectively avoid the confusing feature interaction between masked and visible regions. In this way, the decoder can only speculate based on the information of adjacent image blocks during reconstruction. We assume that this will help the encoder learn more expressive and content-rich features.", + "bbox": [ + 496, + 472, + 892, + 819 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.1.3 Adaptive Decoder.", + "text_level": 1, + "bbox": [ + 500, + 844, + 679, + 859 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The input to the adaptive decoder is the multi-scale masked feature maps of the student followed by a $1 \\times 1$ convolu", + "bbox": [ + 500, + 869, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "6387", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "tion layer to align the channel number. The masked sizes are different in these multi-scale features, which leads to inconsistent feature reconstruction. To alleviate this, we introduce a simple spatial alignment module (SAM) to align them to the same spatial resolution ( $\\frac{1}{32}$ of the input image size in our experiments). As shown in Fig. 4, this is implemented by convolutional layer with stride $p$ or upsampling the spatial resolution by a factor of $\\frac{1}{p}$ (using nearest neighbor upsampling for simplicity), where scaling factor $p = H_i / \\frac{H}{32} = W_i / \\frac{W}{32}$ is the multiplier to the target size. And then, a specific mask token is initialized for each feature scale and then replicated multiple times to replace the features in the masked area. See Fig. 3. Each mask token is a learned vector and is not shared between different feature scales. Different from the fixed input size in the classification task, the input size of the image is flexible, and this requires the same flexible positional embedding generation. We conduct the position encoding in an absolute scale, e.g., $28 \\times 28$ , and adaptively interpolate its resolution according to the input image size. We then add the positional embeddings to all tokens in each feature scale and send them to a series of transformer blocks to perform the feature reconstruction task. The final outputs of the transformer blocks are then restored to the original multi-scale resolutions via the spatial recovery module (SRM). In the SRM, we adopt a linear layer to change the channel numbers to $p^2 \\times C_i^T$ ( $p$ is the same scaling factor used in SAM) and further reshape into the same size as $F_i^T$ . The output of SRM is forced to imitate the teacher's output and learns to reconstruct the missing feature. Note that the adaptive decoder is only used during training to perform the masked KD task.", + "bbox": [ + 76, + 90, + 472, + 559 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.1.4 Distillation Target.", + "text_level": 1, + "bbox": [ + 76, + 561, + 264, + 577 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Denote the output of SRM as $\\hat{F}_i^S\\in \\mathbb{R}^{C_i^T\\times H_i\\times W_i}$ where $i$ indicates the feature index in FPN and $C_i^T,H_i,W_i$ indicate the channel number, height and width of the corresponding feature. The feature-based distillation loss can be formulated as follows:", + "bbox": [ + 76, + 584, + 468, + 660 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {f e a t}} = \\frac {1}{2 N} \\sum_ {i = 0} ^ {\\mathcal {P}} \\left(F _ {i} ^ {T} - \\hat {F} _ {i} ^ {S}\\right) ^ {2}, \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 151, + 666, + 468, + 708 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathcal{P}$ indicates the total number of features in FPN and $\\mathrm{N} = \\mathrm{C_iH_iW_i}$ . $\\hat{F}_i^S$ is the output of $f_{dec}(\\phi (F_i^S),\\mathcal{T}_{mask})$ in Eq (2). Following the state-of-the-art feature-based distillation method FGD [40], we introduce the global distillation loss $\\mathcal{L}_{global}$ to assist the distillation learning, which can be formulated as:", + "bbox": [ + 76, + 713, + 468, + 804 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {g l o b a l}} = \\sum_ {i = 0} ^ {\\mathcal {P}} \\left(R \\left(F _ {i} ^ {T}\\right) - R \\left(\\hat {F} _ {i} ^ {S}\\right)\\right) ^ {2}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 137, + 808, + 468, + 849 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $R$ denotes GCBlock in FGD. Note that before computing $\\mathcal{L}_{feat}$ and $\\mathcal{L}_{global}$ we have $F^S$ and $F^T$ pass a layer normalization operation as well before MSE loss.", + "bbox": [ + 76, + 854, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To summarize, the overall training loss of the proposed MKD includes (a) task loss $L_{task}$ , e.g., classification loss and regression loss in object detection; (b) feature-based distillation loss $L_{feat}$ and $L_{global}$ . It can be formulated as follows:", + "bbox": [ + 496, + 90, + 892, + 165 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\text {t a s k}} + \\lambda \\mathcal {L} _ {\\text {f e a t}} + \\gamma \\mathcal {L} _ {\\text {g l o b a l}} \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 571, + 176, + 890, + 195 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\lambda$ and $\\gamma$ are the weights to balance the distillation losses. The total distillation process is model-agnostic, so it works well with a variety of different structures.", + "bbox": [ + 496, + 205, + 893, + 250 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.2. Discussion", + "text_level": 1, + "bbox": [ + 500, + 258, + 617, + 273 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Feature-based distillation methods [29, 4, 41], such as hint-based [29, 1], attention-based [45, 40], and instance-based [34, 7, 17], have achieved superior performance improvement. They usually make the student imitate the teacher's output given fully visible image input and design different principles to extract the task-aware knowledge to guide the student's learning. But the redundant information in the teacher's feature hinders the complete knowledge learning of the student.", + "bbox": [ + 496, + 282, + 892, + 417 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "As shown in Fig. 5, MGD [41] introduces the feature masking scheme to enhance the feature learning process by partially masking pixels in the feature maps from student's FPN. However, the information in the masked part has already been leaked during the forward process of the full image in the backbone. Thus, when minimizing KD loss, the effect of MGD is divided into two parts. First, since each adjacent pixel of the masked pixel already contains the information of the masked pixel, in the process of pushing student and teacher pair closer together, MGD extracts the masked feature from the leaked information in adjacent pixels and uses convolution to restore it. Second, the pixels around the masked pixels are pushed closer to the corresponding teacher. The effect of MGD is therefore dispersed, and even with the adaptive decoder proposed in our MKD, MGD is still not able to establish the connection between the masked and unmasked area as shown in Tab. 1.", + "bbox": [ + 496, + 417, + 893, + 675 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/6183c0777567a4d79186ae60a63d3c36a7b931ab89c2f761a81961fe10d140cd.jpg", + "image_caption": [ + "Figure 5: Comparison of different distillation paradigms." + ], + "image_footnote": [], + "bbox": [ + 535, + 685, + 859, + 825 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Different from all these paradigms, MKD introduces a global decoder to learn the relationship between the masked", + "bbox": [ + 500, + 869, + 893, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "6388", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/57c2cdb6b6020d652960368f828faff9ec01f045600cda57fb84a4c58cc6ae06.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodmAPAP50AP75
original MGD [41]36.655.139.1
MGD + decoder in our MKD36.655.039.1
", + "bbox": [ + 112, + 88, + 437, + 141 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "area and its surroundings, shown in Fig. 5, promoting the learning of complete knowledge in teacher by KD. MKD masks information in the image space throughout the distillation process, which guarantees that the masked area is completely invisible to the student. Since there is no additional information leakage, MKD more strongly pushes the features of the teacher and the student closer during distillation. Moreover, we visualize the self-attention in the transformer decoder blocks in Fig. 6. To restore the feature of the unseen masked region, the student network is driven to fully learn corresponding knowledge from the adjacent areas. Thus, the feature imitation process is accordingly enhanced. To better understand this, we illustrate the L2 distance between the teacher's and student's features in the adjacent regions in Fig. 2. Our MKD can further enhance the student's learning and demonstrates superior improvement over the previous KD paradigms as shown in Tab. 3 and Tab. 2.", + "bbox": [ + 75, + 176, + 468, + 446 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/86c5a2ca5a8d1b30af54e83ada69ee78e37137841a435f7f8f9809b77d0fc128.jpg", + "image_caption": [ + "Figure 6: The visualization of attention in decoder blocks. The square in red denotes the query." + ], + "image_footnote": [], + "bbox": [ + 117, + 449, + 429, + 503 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 571, + 207, + 589 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In order to evaluate the performance of our proposed method on object detection tasks, we first conduct experiments on the MS COCO dataset [22], which consists of 80 object categories and over $120\\mathrm{k}$ images in total. We use $120\\mathrm{k}$ images for training and $5\\mathrm{k}$ images for testing, following the most common setting. We take mean average precision (mAP) as the evaluation metric of all the detectors. As for the semantic segmentation task, we evaluate our distillation method on the Cityscapes dataset [6] with $5\\mathrm{k}$ high-quality images and evaluate the performance with mean Intersection-over-Union (mIoU). The shown results are the average value of three runs.", + "bbox": [ + 75, + 598, + 467, + 777 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Implementation Details. We train the student models with a batch size of 16 for 24 epochs (known as a $2 \\times$ schedule). The initial learning rate is set by 0.01 for one-stage detectors and 0.02 for two-stage detectors. We reduce the learning rate by $0.1 \\times$ at the 16th and 21st epochs. We adopt an early-stop mask strategy in the last 2 epochs, in which we set the masking ratio as 0.2 with a learning rate of 0.001 and without supervision from the teacher. This follows the co", + "bbox": [ + 75, + 779, + 467, + 900 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/be762333d18997376b458bc6517bf3e1cfef102b60342fc253fad1ce2fa4816e.jpg", + "table_caption": [ + "Table 1: Study on the decoder with Retina Res101-Res18." + ], + "table_footnote": [], + "table_body": "
MethodSchedulemAPAP50AP75
RetinaNet-ResX101(T)2x41.060.944.0
RetinaNet-Res50(S)2x37.456.739.6
FKD [45]2x39.6 (+2.2)58.842.1
FGD [40]2x40.4 (+3.0)59.943.3
MGD [41]2x40.7 (+3.3)59.442.8
MGD* [41]2x41.0 (+3.6)60.744.0
ours2x41.1 (+3.7)60.644.0
ours*2x41.5 (+4.1)61.144.3
RetinaNet-Res101(T)2x38.158.340.9
RetinaNet-MBV2(S)2x31.048.932.7
GID [7]2x33.5 (+2.5)51.935.5
FGD [40]2x35.6 (+4.6)53.838.1
MGD [41]2x35.5 (+4.5)
ours2x36.0 (+5.0)54.538.1
RetinaNet-Swin-s(T)1x39.760.142.2
RetinaNet-Swin-t(S)1x37.257.439.1
FGD [40]1x38.6 (+1.4)58.640.9
F=MGD [41]1x38.1 (+0.9)
ours1x39.3 (+2.1)59.541.6
", + "bbox": [ + 504, + 87, + 893, + 347 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2: Results on COCO dataset with large backbones and swim transformer backbones [26]. T and S denote the teacher and the student, respectively.", + "bbox": [ + 498, + 357, + 890, + 402 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "sine schedule down to 0. In this way, the input distribution of the whole image is consistent with the test image.", + "bbox": [ + 498, + 412, + 890, + 443 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We use SGD as the optimizer and set the momentum and weight decay by 0.9 and 0.0001, respectively. We use the masking ratio of 0.1 by default and set the size of masked patches by 32. The number of adaptive decoder layers is 4. Transformer blocks in the decoder have 256 channels with a head number of 8, and the mlp ratio is set to be 8. The loss weight in Eq. 5 are set to be $\\{\\lambda = 3,\\gamma = 3e - 6\\}$ in single-stage detectors, $\\{\\lambda = 3,\\gamma = 3e - 7\\}$ in two-stage detectors, and $\\{\\lambda = 7,\\gamma = 0\\}$ in segmentation. All the experiments are conducted on 8 GPUs with mmdetection [2] and mmsegmentation [5] on PyTorch.", + "bbox": [ + 496, + 443, + 890, + 609 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Main Results", + "text_level": 1, + "bbox": [ + 500, + 619, + 637, + 633 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Object detection. To verify the effectiveness of the MKD, we conduct experiments on popular detectors, i.e., RetinaNet [21], Faster R-CNN [28] and Reppoints [43] with various backbones, and the results are shown in Tab. 3 and Tab. 2. We can observe that the proposed MKD can consistently improve the student model by more than 2.5 mAP. For example, the Faster R-CNN with ResNet 50 can achieve $41.1\\mathrm{mAP}$ when mimicking Faster R-CNN with ResNet 101 with MKD, which even surpasses the teacher. We further compare our method with the state-of-the-art for detection distillation under fair settings. Our MKD surpasses FGD [40] and MGD [41] on various student-teacher pairs. When distilling the RetinaNet-Res50 model with RetinaNet-ResX101 as the teacher, MKD transcends MGD with 0.4 on mAP and 1.2 on AP50. A similar trend can be observed when we choose smaller students like ResNet 18 as the backbone.", + "bbox": [ + 496, + 643, + 890, + 898 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "6389", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/6babc2353137660ba341a8052db2845c87622df466c92074e1ae6047a264a665.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Method (The default training schedule is 2x)mAPAP50AP75APsAPmAPI
RetinaNet-Res101(Teacher network)38.958.041.521.042.852.4
RetinaNet-Res18(Student network)33.451.835.116.935.644.9
FKD [45]35.9 (+2.5)54.438.017.939.149.1
FGD [40]36.2 (+2.8)54.738.619.540.148.4
MGD [41]36.6 (+3.2)55.139.119.540.350.7
ours37.3 (+3.9)56.139.919.041.051.6
ours*(with the parameter inheriting scheme [17])37.5 (+4.1)56.039.919.441.551.2
RetinaNet-Res101(Teacher network)38.958.041.521.042.852.4
RetinaNet-Res50(Student network)37.456.739.620.040.749.7
GID [7]39.1 (+1.7)59.042.322.843.152.3
FGD [40]39.6 (+2.2)58.542.522.943.753.6
MGD [41]39.5 (+2.1)58.542.221.343.653.4
ours39.9 (+2.5)59.042.722.343.953.3
ours*(with the parameter inheriting scheme [17])40.2 (+2.8)59.343.022.344.454.0
FasterRCNN-Res101(Teacher network)39.860.143.322.543.652.8
FasterRCNN-Res50(Student network)38.459.042.021.542.150.3
FGFI [34]39.3 (+0.9)59.842.922.542.352.2
GID [7]40.2 (+1.8)60.743.822.744.053.2
FGD [40]40.4 (+2.0)60.744.322.844.553.5
MGD [41]40.1 (+1.7)60.243.622.944.253.3
ours41.0 (+2.6)61.544.723.545.553.4
ours*(with the parameter inheriting scheme [17])41.1 (+2.7)61.544.824.445.154.3
FCOS-Res101(Teacher network)40.860.044.024.244.352.4
FCOS-Res50(Student network)38.557.741.021.942.848.6
GID [7]42.0 (+3.5)60.445.525.645.854.2
FGD [40]42.1 (+3.6)--27.046.054.6
MGD [41]42.2(+3.7)60.945.326.646.354.7
ours42.5 (+4.0)61.246.126.646.854.6
ours*(with the parameter inheriting scheme [17])43.1 (+4.6)61.746.727.347.155.1
Reppoints-ResX101(Teacher network)44.265.547.826.248.458.5
Reppoints-Res50(Student network)38.659.641.622.542.250.4
FKD [45]40.6 (+2.0)61.743.823.444.653.0
FGD [40]41.3 (+2.7)--24.545.254.0
MGD [41]41.8 (+3.2)62.844.824.245.855.6
MGD [41]*(with the parameter inheriting scheme [17])42.3 (+3.7)63.345.424.446.255.9
ours42.2 (+3.6)63.045.624.346.455.7
ours*(with the parameter inheriting scheme [17])43.0 (+4.4)63.846.124.447.257.1
", + "bbox": [ + 114, + 87, + 859, + 583 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 3: Object detection performance of our proposed MKD with various teacher-student pairs on the COCO dataset.", + "bbox": [ + 94, + 592, + 870, + 608 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Moreover, our method can benefit from a longer training schedule. For example, when training for 36 epochs, our MKD can further improve the performance of the student model over $4.0\\mathrm{mAP}$ , which surpasses other methods by a larger margin than that for 12 epochs. This demonstrates that introducing a masked autoencoder into knowledge distillation can help the student avoid early saturation and benefit more from the distillation process.", + "bbox": [ + 75, + 633, + 470, + 755 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Semantic segmentation. Our MKD can be easily transferred to segmentation tasks such as semantic segmentation, and we conduct knowledge distillation experiments to show the generality of the proposed method. We choose PspNet-Res101 [47] as the teacher to distill PspNet-Res18 and DeepLabV3-Res18 [3]. As shown in Tab. 5, our method improves the PspNet-Res18 model with $4.85\\mathrm{mIoU}$ , which greatly fills the gap between the student and the teacher. Also, MKD surpasses MGD and other methods by a signif", + "bbox": [ + 75, + 763, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "icant margin, which verifies the effectiveness and generality of our method.", + "bbox": [ + 496, + 633, + 890, + 662 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Image classification. Since the core bottleneck is particularly prominent in fine-grained visual tasks that rely on spatial localization information, we mainly evaluate our methods on them. We also present the result of MKD on the classification task in Tab. 6, which further verifies its effectiveness.", + "bbox": [ + 496, + 666, + 890, + 755 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.2. Ablation Study", + "text_level": 1, + "bbox": [ + 498, + 768, + 653, + 787 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Masking ratio. We first examine the influence of different masking ratios on the performance shown in Fig. 7. Large masking ratios benefit more from longer training schedules. For example, a masking ratio of 0.1 achieves the best under a 1x schedule, while the best one changes to 0.3 under a 3x schedule. This is because a larger masking ratio introduces more difficulty to the distillation process and needs more", + "bbox": [ + 496, + 794, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "6390", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/bb32b0653227e6bb7a68244adb51e4bd87681786bec9401e105ba4869ded1945.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Patch SizemAPAP50AP75
Baseline37.456.739.6
1639.859.242.5
3239.959.342.5
6439.859.042.7
", + "bbox": [ + 102, + 101, + 289, + 169 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/8a257637608b45d626d432abb3f68745f8a93bbf4ab8a31b1314ac684bcac116.jpg", + "table_caption": [ + "(a) The patch size." + ], + "table_footnote": [], + "table_body": "
ResolutionmAPAP50AP75
w/o SAM, SRMOOM--
[H/16, W/16]38.958.041.6
[H/32, W/32]39.959.342.5
[H/64, W/64]39.759.142.2
", + "bbox": [ + 312, + 101, + 532, + 170 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/2f231e18350270c89238ce5dc28bc41b2d01d457b826ec19d588eaaa7feb926f.jpg", + "table_caption": [ + "(b) The aligned resolution in SAM." + ], + "table_footnote": [], + "table_body": "
λmAPAP50AP75
039.658.842.5
139.959.242.8
339.959.342.5
539.759.042.6
", + "bbox": [ + 540, + 101, + 692, + 170 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/11a2a72ea076fd4a4e23124cd62132f9af948191994fc47e7dd644542b6b48ec.jpg", + "table_caption": [ + "(c) The loss weights $\\lambda$" + ], + "table_footnote": [], + "table_body": "
γmAPAP50AP75
039.759.042.6
1e-639.758.942.2
3e-639.959.342.5
5e-639.859.242.6
", + "bbox": [ + 718, + 101, + 870, + 169 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/4d3446f4df478f3e86ad2040282ab17d0b26db7990e622329f91e682c9c87dde.jpg", + "table_caption": [ + "(d) The loss weights $\\gamma$" + ], + "table_footnote": [], + "table_body": "
DepthmAPAP50AP75
Baseline37.456.739.6
239.658.742.4
439.959.342.5
839.859.042.3
", + "bbox": [ + 106, + 198, + 315, + 266 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/0ad2b3df24c1b02a633e29d003db0e34b0d14853d3e2450db3eba75183fa72a7.jpg", + "table_caption": [ + "(e) The depth of the adaptive decoder $N$" + ], + "table_footnote": [], + "table_body": "
Masked ConvolutionmAPAP50AP75
Baseline37.456.739.6
w/o39.658.842.5
w/39.959.342.5
", + "bbox": [ + 354, + 198, + 584, + 266 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/661911048174227844c05195f40c7373ace63a7ae69ad6d0a86529592d34f485.jpg", + "table_caption": [ + "(f) The masked convolution." + ], + "table_footnote": [], + "table_body": "
Mask StrategymAPAP50AP75
Baseline37.456.739.6
Random39.959.342.5
Grid37.857.040.2
Block39.759.242.7
", + "bbox": [ + 625, + 198, + 867, + 267 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/d37b28f2852a2712f369c275d5029808eeccc0d751e618ecc913f3e364101c65.jpg", + "table_caption": [ + "(g) The masking strategy.", + "Table 4: Ablation study on the MKD design with RetinaNet-ResNet50 as student and RetinaNet-ResNeXt101 as a teacher under 1x training schedule. If not specified, the patch size is 32, $\\lambda = 3$ , $\\gamma = 3e - 6$ , the decoder has a depth of 4, and the mask is randomly sampled." + ], + "table_footnote": [], + "table_body": "
MethodinputsizemIoU
PspNet-Res101(T)512x102478.34
PspNet-Res18(S)512x51269.85
SKDS [25]512x51272.70
CWD [30]512x51273.53
MGD [41]512x51273.63
MGD* [41]512x51274.10
ours512x51273.99
ours*512x51274.70
PspNet-Res101(T)512x102478.34
DeepLabV3-Res18(S)512x51273.20
SKDS [25]512x51273.87
CWD [30]512x51275.93
MGD [41]512x51276.02
MGD* [41]512x51276.31
ours512x51276.14
ours*512x51276.63
", + "bbox": [ + 132, + 345, + 418, + 568 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/bf9f0c980b3601bf3183164003826d3aa837823553309687204ec12a4d1eb536.jpg", + "table_caption": [ + "Table 5: Semantic segmentation result on Cityscape dataset. * means adopting an extra logits loss from CWD [30]." + ], + "table_footnote": [], + "table_body": "
MethodTop-1Top-5
ResNet-34(T)73.6291.59
ResNet-18(S)69.9089.43
FitNet [29]71.5090.27
SRRL [39]71.7390.60
MGD [41]71.8090.40
Ours72.0190.43
", + "bbox": [ + 151, + 616, + 397, + 712 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 6: The performance of classification on ImageNet.", + "bbox": [ + 84, + 723, + 459, + 739 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "optimization steps for the student to converge.", + "bbox": [ + 76, + 750, + 382, + 763 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Masked convolution. To keep the masked patches not affected by others in the convolution block, we introduce the masked convolution in our MKD, and the results of ablation on masked convolution are shown in Tab. 4f. Removing masked convolution from MKD will lead to a reduction of $0.3\\mathrm{mAP}$ , which is still better than that of the baseline. This demonstrates that the masking operation indeed hinders the optimization of convolution blocks, and adopting masked convolution can effectively alleviate this issue.", + "bbox": [ + 75, + 763, + 468, + 900 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/84731a4abba1ba636fe5472e2fd61320167eb230298fa464046634fda03591ef.jpg", + "image_caption": [ + "Figure 7: Illustration of the performance improvement of different masking ratios under different schedules. It appears that MKD (green) brings the greatest boost to the baseline (36.5mAP)." + ], + "image_footnote": [], + "bbox": [ + 576, + 362, + 792, + 487 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Mask patch size. Here we examine how the masked patch size influences the distillation process. As shown in Tab. 4a, a patch size of 32 performs the best than other options. A smaller patch will lead to the confusing assignment of masked position in the last stage, which leads to inferior performance. On the contrary, using a larger patch size may distort the objects too much and make the edge vague. So we use a masked patch size of 32 by default in our work.", + "bbox": [ + 496, + 580, + 890, + 700 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "SAM and SRM. We compare different aligned resolutions in SAM, and the results are shown in Tab. 4b. The training process appears to be out of memory(OOM) without spatial alignment operation, indicating that SAM and SRM are important in reducing computation and memory. We further found that setting the target resolution as $\\frac{H}{32} \\times \\frac{W}{32}$ performs the best because it is the same size as the masked patches.", + "bbox": [ + 496, + 702, + 890, + 808 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Mask sampling strategies. Here we examine the influence of different masking strategies, e.g., masking randomly, masking in grids, and masking by block. Recent masked image modeling works show that random strategy works the best, and we observe a similar trend in our MKD. Note that to prevent the student network from learning the mask pat", + "bbox": [ + 496, + 810, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "6391", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "tern, it is necessary to use a global random mask. As shown in Tab. 4g, random masking surpasses other ways and is selected in other experiments in this paper.", + "bbox": [ + 75, + 90, + 468, + 136 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Adaptive decoder design. Adaptive decoder helps to reconstruct masked features from visible ones and is an important module in MKD. We choose different numbers of decoder layers and examine their effects on distillation performance. As shown in Tab. 4e, four layers perform the best. Due to the feature dimension and length of the sequence, we use four layers by default. Objects of different scales correspond to different feature levels of FPN, so we use unshared tokens for the reconstruction. While shared tokens cause a performance drop from $37.3\\mathrm{mAP}$ to $37.0\\mathrm{mAP}$ .", + "bbox": [ + 75, + 137, + 468, + 300 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Loss weight. In Eq. 5, we use two hyper-parameters $\\lambda$ and $\\gamma$ to balance the distillation loss, and we conduct ablation studies to investigate their sensitivities of them. From Tab. 4d and 4c, it can be seen that the performance of the student model is not sensitive to the choices of $\\lambda$ and $\\gamma$ , as the gap between the worst and the best is within $0.2\\mathrm{mAP}$ . Note that $L_{feat}$ and $L_{global}$ are both distillation losses to calculate the similarity between the reconstructed output of the decoder $\\hat{F}^S$ and teacher feature $F^T$ . The main difference is that $L_{feat}$ directly calculates MSE, and $L_{global}$ goes through a GCblock. Hence, the performance drop is small when $\\lambda = 0$ or $\\gamma = 0$ , as MKD already works when using either of the loss alone.", + "bbox": [ + 75, + 301, + 470, + 498 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 512, + 194, + 527 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this paper, we propose a new distillation paradigm Masked Knowledge Distillation (MKD), which introduces the masked autoencoding scheme to enhance the knowledge distillation process. MKD takes the masked image as input and predicts the whole feature map that is used to imitate the corresponding feature of the teacher network. By forcing the student network to learn the knowledge of the nearby region of the masked part to recover the full feature, the student can better transfer the corresponding information from the teacher, which helps to excavate the potential of the small student network. Extensive experimental results on various fine-grained visual tasks show its power in enhancing the improvement of knowledge distillation.", + "bbox": [ + 75, + 537, + 468, + 734 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement", + "text_level": 1, + "bbox": [ + 76, + 748, + 236, + 765 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work was partly supported by the National Natural Science Foundation of China (Grant No. 61991451) and the Shenzhen Science and Technology Program (JCYJ20220818101001004).", + "bbox": [ + 75, + 772, + 468, + 834 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 76, + 847, + 173, + 863 + ], + "page_idx": 8 + }, + { + "type": "ref_text", + "text": "[1] Guobin Chen, Wongun Choi, Xiang Yu, Tony Han, and Manmohan Chandraker. Learning efficient object detection mod", + "bbox": [ + 84, + 872, + 468, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "els with knowledge distillation. In NIPS, pages 742-751, 2017. 2, 3, 5", + "[2] Kai Chen, Jiaqi Wang, Jiangmiao Pang, Yuhang Cao, Yu Xiong, Xiaoxiao Li, Shuyang Sun, Wansen Feng, Ziwei Liu, Jiarui Xu, et al. Mmdetection: Open mmlab detection toolbox and benchmark. arXiv preprint arXiv:1906.07155, 2019. 6", + "[3] Liang-Chieh Chen, George Papandreou, Florian Schroff, and Hartwig Adam. Rethinking atrous convolution for semantic image segmentation. arXiv preprint arXiv:1706.05587, 2017. 7", + "[4] Pengguang Chen, Shu Liu, Hengshuang Zhao, and Jiaya Jia. Distilling knowledge via knowledge review. In CVPR, pages 5008-5017, 2021. 1, 5", + "[5] MMSegmentation Contributors. Mmsegmentation: Openmmlab semantic segmentation toolbox and benchmark. https://github.com/open-mmlab/mmsegmentation, 2020.6", + "[6] Marius Cordts, Mohamed Omran, Sebastian Ramos, Timo Rehfeld, Markus Enzweiler, Rodrigo Benenson, Uwe Franke, Stefan Roth, and Bernt Schiele. The cityscapes dataset for semantic urban scene understanding. In CVPR, pages 3213-3223, 2016. 6", + "[7] Xing Dai, Zeren Jiang, Zhao Wu, Yiping Bao, Zhicheng Wang, Si Liu, and Erjin Zhou. General instance distillation for object detection. In CVPR, pages 7842-7851, 2021. 1, 3, 5, 6, 7", + "[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In ICLR, 2020. 4", + "[9] Kaiwen Duan, Song Bai, Lingxi Xie, Honggang Qi, Qingming Huang, and Qi Tian. Centernet: Keypoint triplets for object detection. In ICCV, pages 6569-6578, 2019. 3", + "[10] Peng Gao, Teli Ma, Hongsheng Li, Jifeng Dai, and Yu Qiao. Convmae: Masked convolution meets masked autoencoders. arXiv preprint arXiv:2205.03892, 2022. 2, 4", + "[11] Kunyang Han, Yong Liu, Jun Hao Liew, Henghui Ding, Yunchao Wei, Jiajun Liu, Yitong Wang, Yansong Tang, Yujiu Yang, Jiashi Feng, et al. Global knowledge calibration for fast open-vocabulary segmentation. arXiv preprint arXiv:2303.09181, 2023. 1", + "[12] Song Han, Jeff Pool, John Tran, and William Dally. Learning both weights and connections for efficient neural network. NIPS, 28, 2015. 3", + "[13] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollar, and Ross Girshick. Masked autoencoders are scalable vision learners. In CVPR, pages 16000-16009, 2022. 4", + "[14] Kaiming He, Georgia Gkioxari, Piotr Dólar, and Ross Girshick. Mask r-cnn. In ICCV, pages 2961-2969, 2017. 3", + "[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778, 2016. 1", + "[16] Geoffrey Hinton, Oriol Vinyals, and Jeff Dean. Distilling the knowledge in a neural network. Computer Science, 14(7):38-39, 2015. 1, 3" + ], + "bbox": [ + 501, + 92, + 893, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "6392", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[17] Zijian Kang, Peizhen Zhang, Xiangyu Zhang, Jian Sun, and Nanning Zheng. Instance-conditional knowledge distillation for object detection. NIPS, 34:16468-16480, 2021. 1, 3, 5, 7", + "[18] Quanquan Li, Shengying Jin, and Junjie Yan. Mimicking very efficient network for object detection. In CVPR, pages 6356-6364, 2017. 1", + "[19] Rundong Li, Yan Wang, Feng Liang, Hongwei Qin, Junjie Yan, and Rui Fan. Fully quantized network for object detection. In CVPR, pages 2810-2819, 2019. 3", + "[20] Tsung-Yi Lin, Piotr Dólar, Ross Girshick, Kaiming He, Bharath Hariharan, and Serge Belongie. Feature pyramid networks for object detection. In CVPR, pages 2117-2125, 2017. 1", + "[21] Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dólar. Focal loss for dense object detection. In ICCV, pages 2980-2988, 2017. 3, 6", + "[22] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dálár, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In ECCV, pages 740-755. Springer, 2014. 6", + "[23] Guilin Liu, Fitsum A Reda, Kevin J Shih, Ting-Chun Wang, Andrew Tao, and Bryan Catanzaro. Image inpainting for irregular holes using partial convolutions. In ECCV, pages 85-100, 2018. 2, 4", + "[24] Wei Liu, Dragomir Anguelov, Dumitru Erhan, Christian Szegedy, Scott Reed, Cheng-Yang Fu, and Alexander C Berg. Ssd: Single shot multibox detector. In ECCV, pages 21-37. Springer, 2016. 3", + "[25] Yifan Liu, Ke Chen, Chris Liu, Zengchang Qin, Zhenbo Luo, and Jingdong Wang. Structured knowledge distillation for semantic segmentation. In CVPR, pages 2604-2613, 2019. 8", + "[26] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In ICCV, pages 10012-10022, 2021. 6", + "[27] Mengye Ren, Andrei Pokrovsky, Bin Yang, and Raquel Urtasun. Sbnet: Sparse blocks network for fast inference. In CVPR, pages 8711-8720, 2018. 4", + "[28] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. NIPS, 28, 2015. 3, 6", + "[29] Adriana Romero, Nicolas Ballas, Samira Ebrahimi Kahou, Antoine Chassang, Carlo Gatta, and Yoshua Bengio. Fitnets: Hints for thin deep nets. arXiv preprint arXiv:1412.6550, 2014. 1, 3, 5, 8", + "[30] Changyong Shu, Yifan Liu, Jianfei Gao, Zheng Yan, and Chunhua Shen. Channel-wise knowledge distillation for dense prediction. In ICCV, pages 5311-5320, 2021. 8", + "[31] Mingxing Tan, Ruoming Pang, and Quoc V Le. Efficientdet: Scalable and efficient object detection. In CVPR, pages 10781-10790, 2020. 3", + "[32] Zhi Tian, Chunhua Shen, Hao Chen, and Tong He. Fcos: Fully convolutional one-stage object detection. In ICCV, pages 9627-9636, 2019. 3" + ], + "bbox": [ + 78, + 90, + 468, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[33] Jiahao Wang, Mingdeng Cao, Shuwei Shi, Baoyuan Wu, and Yujiu Yang. Attention probe: Vision transformer distillation in the wild. In ICASSP, pages 2220-2224. 3", + "[34] Tao Wang, Li Yuan, Xiaopeng Zhang, and Jiashi Feng. Distilling object detectors with fine-grained feature imitation. In CVPR, pages 4933-4942, 2019. 1, 2, 3, 5, 7", + "[35] Xinlong Wang, Rufeng Zhang, Tao Kong, Lei Li, and Chunhua Shen. Solov2: Dynamic and fast instance segmentation. NIPS, 33:17721-17732, 2020. 3", + "[36] Yi Wei, Xinyu Pan, Hongwei Qin, Wanli Ouyang, and Junjie Yan. Quantization mimic: Towards very tiny cnn for object detection. In ECCV, pages 267-283, 2018. 3", + "[37] Taiqiang Wu, Cheng Hou, Zhe Zhao, Shanshan Lao, Jiayi Li, Ngai Wong, and Yujiu Yang. Weight-inherited distillation for task-agnostic bert compression, 2023. 3", + "[38] Xiang Xiang, Zhiyuan Wang, Shanshan Lao, and Baochang Zhang. Pruning multi-view stereo net for efficient 3d reconstruction. ISPRS Journal of Photogrammetry and Remote Sensing, 168:17-27, 2020. 3", + "[39] Jing Yang, Brais Martinez, Adrian Bulat, Georgios Tzimiropoulos, et al. Knowledge distillation via softmax regression representation learning. ICLR, 2021. 8", + "[40] Zhendong Yang, Zhe Li, Xiaohu Jiang, Yuan Gong, Zehuan Yuan, Danpei Zhao, and Chun Yuan. Focal and global knowledge distillation for detectors. In CVPR, pages 4643-4652, 2022. 1, 2, 3, 5, 6, 7", + "[41] Zhendong Yang, Zhe Li, Mingqi Shao, Dachuan Shi, Zehuan Yuan, and Chun Yuan. Masked generative distillation. arXiv preprint arXiv:2205.01529, 2022. 3, 5, 6, 7, 8", + "[42] Zhendong Yang, Zhe Li, Ailing Zeng, Zexian Li, Chun Yuan, and Yu Li. Vitkd: Practical guidelines for vit feature knowledge distillation. arXiv preprint arXiv:2209.02432, 2022. 3", + "[43] Ze Yang, Shaohui Liu, Han Hu, Liwei Wang, and Stephen Lin. Repoints: Point set representation for object detection. In ICCV, pages 9657-9666, 2019. 3, 6", + "[44] Zhendong Yang, Ailing Zeng, Zhe Li, Tianke Zhang, Chun Yuan, and Yu Li. From knowledge distillation to self-knowledge distillation: A unified approach with normalized loss and customized soft labels. arXiv preprint arXiv:2303.13005, 2023. 3", + "[45] Linfeng Zhang and Kaisheng Ma. Improve object detection with feature-based knowledge distillation: Towards accurate and efficient detectors. In ICLR, 2020. 1, 3, 5, 6, 7", + "[46] Borui Zhao, Quan Cui, Renjie Song, Yiyu Qiu, and Jiajun Liang. Decoupled knowledge distillation. In CVPR, pages 11953-11962, 2022. 1, 2, 3", + "[47] Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, and Jiaya Jia. Pyramid scene parsing network. In CVPR, pages 2881-2890, 2017. 7" + ], + "bbox": [ + 503, + 92, + 890, + 787 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "6393", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/Masked Autoencoders Are Stronger Knowledge Distillers/801459a1-6a61-45c0-b371-eb489abaf84f_model.json b/2023/Masked Autoencoders Are Stronger Knowledge Distillers/801459a1-6a61-45c0-b371-eb489abaf84f_model.json new file mode 100644 index 0000000000000000000000000000000000000000..0ea39da5207e5eb15a2cd9150c9fb8f75ce129d3 --- /dev/null +++ b/2023/Masked Autoencoders Are Stronger Knowledge Distillers/801459a1-6a61-45c0-b371-eb489abaf84f_model.json @@ -0,0 +1,2189 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.196, + 0.131, + 0.776, + 0.154 + ], + "angle": 0, + "content": "Masked Autoencoders Are Stronger Knowledge Distillers" + }, + { + "type": "text", + "bbox": [ + 0.196, + 0.179, + 0.777, + 0.233 + ], + "angle": 0, + "content": "Shanshan Lao1* Guanglu Song2 Boxiao Liu2 Yu Liu2† Yujiu Yang1† \n1Tsinghua Shenzhen International Graduate School, Tsinghua University \n2Sensetime Research" + }, + { + "type": "text", + "bbox": [ + 0.179, + 0.237, + 0.792, + 0.27 + ], + "angle": 0, + "content": "laoss21@mails.tsinghua.edu.cn, {songguanglu, liuboxiao}@sensetime.com \nliuyuisanai@gmail.com, yang.yujiu@sz.tsinghua.edu.cn" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.305, + 0.314, + 0.32 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.338, + 0.474, + 0.745 + ], + "angle": 0, + "content": "Knowledge distillation (KD) has shown great success in improving student's performance by mimicking the intermediate output of the high-capacity teacher in fine-grained visual tasks, e.g. object detection. This paper proposes a technique called Masked Knowledge Distillation (MKD) that enhances this process using a masked autoencoding scheme. In MKD, random patches of the input image are masked, and the corresponding missing feature is recovered by forcing it to imitate the output of the teacher. MKD is based on two core designs. First, using the student as the encoder, we develop an adaptive decoder architecture, which includes a spatial alignment module that operates on the multi-scale features in the feature pyramid network (FPN) [20], a simple decoder, and a spatial recovery module that mimics the teacher's output from the latent representation and mask tokens. Second, we introduce the masked convolution in each convolution block to keep the masked patches unaffected by others. By coupling these two designs, we can further improve the completeness and effectiveness of teacher knowledge learning. We conduct extensive experiments on different architectures with object detection and semantic segmentation. The results show that all the students can achieve further improvements compared to the conventional KD. Notably, we establish the new state-of-the-art results by boosting RetinaNet ResNet-18, and ResNet-50 from 33.4 to 37.5 mAP, and 37.4 to 41.5 mAP, respectively." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.751, + 0.21, + 0.767 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.772, + 0.47, + 0.864 + ], + "angle": 0, + "content": "As fundamental tasks in computer vision, high-level visual predictions such as object detection, instance segmentation, and semantic segmentation have been widely used in various practical applications. In real-world scenarios, improving the performance of the deployable models is crucial. Improving the performance of a lightweight student" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.304, + 0.581, + 0.425 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.519, + 0.425, + 0.566, + 0.434 + ], + "angle": 0, + "content": "Input Image" + }, + { + "type": "image", + "bbox": [ + 0.582, + 0.304, + 0.658, + 0.425 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.586, + 0.425, + 0.654, + 0.433 + ], + "angle": 0, + "content": "Feature of teacher" + }, + { + "type": "image", + "bbox": [ + 0.659, + 0.304, + 0.735, + 0.425 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.684, + 0.425, + 0.71, + 0.433 + ], + "angle": 0, + "content": "FitNet" + }, + { + "type": "image", + "bbox": [ + 0.735, + 0.304, + 0.811, + 0.425 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.763, + 0.425, + 0.785, + 0.433 + ], + "angle": 0, + "content": "FGD" + }, + { + "type": "image", + "bbox": [ + 0.812, + 0.304, + 0.89, + 0.425 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.839, + 0.425, + 0.863, + 0.433 + ], + "angle": 0, + "content": "MKD" + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.444, + 0.893, + 0.492 + ], + "angle": 0, + "content": "Figure 1: Visualization of feature maps of teacher networks (RetinaNet-ResX101) and student networks (RetinaNet-Res50) with different KD paradigms." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.503, + 0.893, + 0.626 + ], + "angle": 0, + "content": "model via a high-capacity teacher introduces an effective paradigm, which is widely known as Knowledge Distillation (KD) [16, 4]. For dense visual prediction tasks, feature-based distillation [17, 7, 11] is more beneficial for the student to mimic the teacher's intermediate features. Some elaborated feature-based distillation methods [29, 4, 40, 18] have established the state-of-the-art performance for many lightweight models such as ResNet-18 [15]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.629, + 0.895, + 0.902 + ], + "angle": 0, + "content": "The core bottleneck of such feature-based KD is how to learn the complete knowledge from the teacher's output containing about 20K spatial coordinates (calculated on the COCO training set). According to our experiment, \\(72\\%\\) of them are simple enough and converge quickly to achieve \\(\\sim 90\\%\\) similarity with the teacher's output. The remaining important knowledge is suppressed by this large number of simple samples, and it is difficult for the student to learn effectively. To further verify the existence of information redundancy in teacher features, we conduct experiments that, when \\(30\\%\\) of the features are randomly masked during training and testing on Retina-R101 (38.4 mAP), it still achieved similar performance (38.1 mAP). Previous works [34, 46] point out similar observations that each pixel contributes equally if using a common distillation loss (e.g. MSE), which will cause the network to easily learn a lot of similar information and is hard to identify important information. So they use attention [45, 40] and decouple the" + }, + { + "type": "page_footnote", + "bbox": [ + 0.095, + 0.875, + 0.383, + 0.888 + ], + "angle": 0, + "content": "*Work done during internship at SenseTime Research." + }, + { + "type": "page_footnote", + "bbox": [ + 0.098, + 0.888, + 0.227, + 0.9 + ], + "angle": 0, + "content": "† Corresponding authors." + }, + { + "type": "list", + "bbox": [ + 0.095, + 0.875, + 0.383, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6384" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.137 + ], + "angle": 0, + "content": "foreground and background feature [34, 46] to help alleviate this problem. But attention can still lead to the imbalance of information learning." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.14, + 0.471, + 0.473 + ], + "angle": 0, + "content": "In order to learn the complete information without being affected by the spatial redundancy in teacher features, we introduce the Mask Image Modeling (MIM) mechanism to effectively promote the learning of this information. To be more specific, we propose a new Masked Knowledge Distillation (MKD) framework to improve the knowledge learning of the student via the masked autoencoding paradigm. The core idea is that we mask random patches of the input image of the student while maintaining the whole input image for the teacher, and then recover the corresponding missing feature by forcing the student to imitate the output of the teacher. In this way, the student network is encouraged to predict the masked patches with corrupted input images and learn the relationship between the masked area and its surrounding regions, rather than simply imitating the output feature of the teacher at visible patches. We conduct some experiments trying to excavate the potential ability of the students. As shown in Fig. 1, according to the feature comparison in the red box, it can be observed that student network using MKD learns more complete knowledge from teacher than the direct feature-based method [1] and the attention-based method [40]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.476, + 0.471, + 0.793 + ], + "angle": 0, + "content": "We introduce two crucial designs to alleviate some bottlenecks in this framework. First, due to the masked image input, directly applying the normal convolution in the convolutional neural networks (CNN) will confuse the latent representation in visible and invisible patches. Therefore, we adopt the masked convolution [10, 23] to keep the masked patches not affected by others in each convolution block. Second, multi-scale features are often used in fine-grained high-level visual tasks which have different masked sizes, leading to inconsistent feature reconstruction. We developed an adaptive decoder architecture for this problem to predict the teacher's feature in the corresponding masked area. More specifically, a spatial alignment module is first operated on the multi-scale features to align them to the same spatial resolution. A mask token is then replicated multiple times to replace the features in the masked area. The features in the visible patches and mask tokens are sent to an adaptive transformer decoder to reconstruct the teacher's feature. Finally, we conduct the spatial recovery module to convert the same spatial resolution to the original multi-scale resolution to perform feature-based distillation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.796, + 0.47, + 0.903 + ], + "angle": 0, + "content": "In our method, by the mask autoencoding paradigm with asymmetric input for student and teacher, the student is forced to infer the teacher's features in the invisible patches by imitating the teacher's features in the visible patches. We observe that the mask tokens in the decoder try to absorb knowledge from their adjacent region to restore the features in the masked region. Completely restoring the masked fea" + }, + { + "type": "image", + "bbox": [ + 0.558, + 0.108, + 0.819, + 0.259 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.27, + 0.892, + 0.316 + ], + "angle": 0, + "content": "Figure 2: The average L2 distance between student's feature and teacher's feature calculated at the unmasked areas with RetinaNet-ResX101 distilling RetinaNet-Res50." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.323, + 0.892, + 0.534 + ], + "angle": 0, + "content": "tures drives it to fully learn the teacher's corresponding information in these adjacent areas. As shown in Fig. 2, the L2 distance value in adjacent regions of the mask can be lower with masked input. This verifies the claim that the student network can better learn the teacher's knowledge in our learning manner. MKD can be directly used in different architectures and various dense visual prediction tasks, e.g., object detection and semantic segmentation. The results show that MKD can improve considerably cooperated with conventional feature-based distillation. For instance, with MKD in RetinaNet, the mAP of student ResNet-18 is greatly improved to 37.5, \\(4.1\\%\\) higher than the baseline, and also outperforms the previous SOTA methods. To sum up, our contributions are as follows:" + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.537, + 0.892, + 0.628 + ], + "angle": 0, + "content": "- We propose a new paradigm for feature-based distillation named MKD, using mask autoencoding scheme to effectively learn the complete knowledge in the teacher network. MKD masks random patches of the input image and recovers the corresponding masked feature by forcing it to imitate the teacher's output." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.636, + 0.892, + 0.698 + ], + "angle": 0, + "content": "- We introduce the masked convolution and adaptive decoder module in MKD to make it easy to cooperate with different architectures in fine-grained visual tasks, e.g., object detection and semantic segmentation." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.706, + 0.892, + 0.781 + ], + "angle": 0, + "content": "- Extensive experiments on various models and tasks verify the effectiveness of our method. For different student architectures and tasks, MKD can further improve the performance of feature-based distillation and establish new state-of-the-art." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.537, + 0.892, + 0.781 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.793, + 0.651, + 0.808 + ], + "angle": 0, + "content": "2. Related Works" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.818, + 0.667, + 0.834 + ], + "angle": 0, + "content": "2.1. Object Detection" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.841, + 0.892, + 0.903 + ], + "angle": 0, + "content": "As a fundamental and challenging task in computer vision, object detection aims to detect the visual objects of a certain class in the images. Modern object detectors can be broadly divided into three paradigms: two-" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6385" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.099, + 0.089, + 0.565, + 0.351 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.572, + 0.102, + 0.875, + 0.348 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.36, + 0.895, + 0.406 + ], + "angle": 0, + "content": "Figure 3: Illustration of the MKD. For clear visualization, we omit the original task losses, such as classification and localization loss. In this learning process, the parameter of the teacher is fixed. The mask token and decoder are not shared between different-scale features in FPN due to the semantic gap in different-scale features." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.414, + 0.473, + 0.581 + ], + "angle": 0, + "content": "stage [28, 14, 35], anchor-based one-stage [21, 32, 24], and anchor-free one-stage [43, 9]. While detectors with strong backbones have better accuracy, they are computationally expensive and difficult to deploy on mobile devices. One interesting direction of research is the compression of detection networks, including quantization [36, 19], pruning [12, 38], and the design of lightweight networks [31]. In addition, Knowledge Distillation (KD) [16, 46, 37], has become an important method for transferring knowledge from larger, better-performing networks without changing the structure of the network." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.591, + 0.395, + 0.607 + ], + "angle": 0, + "content": "2.2. Knowledge Distillation for Detection" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.614, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Knowledge distillation is a model compression and acceleration method that can transfer knowledge from the teacher model to the student model. The logit-based distillation methods [16, 46, 44] in classification are limited for the improvement of the fine-grained visual understanding tasks because the localization information from the teacher is crucial. Therefore, feature-based distillation over multiscale features has become the main method of distillation for detectors. Current feature distillation methods for detectors can be divided into the following four categories: (1) hint-based, (2) attention-based, (3) instance-based, and (4) masked-feature based. Hint-based methods [29, 1, 33, 42] take features from the intermediate layers as hints to guide the student model. However, such methods treat all regions equally and do not get satisfactory results. Instance-based methods aim to find the key instance regions for distillation by GT boxes or specifically designed modules, e.g. FGFI [34], GID [7], ICD [17]. Attention-based methods further improve the performance by using attention maps to" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.414, + 0.895, + 0.581 + ], + "angle": 0, + "content": "locate discriminative areas, e.g. FKD [45], FGD [40]. Recent work MGD [41] first proposed to mask out the feature maps in the knowledge distillation branch and use a generator to restore the teacher feature. In our work, we mask random patches of the original images and adopt masked convolution into the backbone network to prevent information leakage. This new paradigm introduces masks throughout the backbone network, enhancing the corresponding knowledge learning in adjacent regions of the random mask. Experiments have shown that distillation benefits well from the masking scheme, especially for longer schedules." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.595, + 0.61, + 0.612 + ], + "angle": 0, + "content": "3. Approach" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.619, + 0.779, + 0.636 + ], + "angle": 0, + "content": "3.1. Masked Knowledge Distillation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.643, + 0.894, + 0.735 + ], + "angle": 0, + "content": "We first elaborate on the overall pipeline of our masked knowledge distillation (MKD) by instantiating an example in object detection. Let \\( F^{S} \\in \\mathbb{R}^{C \\times H \\times W} \\) and \\( F^{T} \\in \\mathbb{R}^{C \\times H \\times W} \\) denote the output features of student's FPN and teacher's FPN, respectively. The standard feature-based distillation can be formulated as:" + }, + { + "type": "equation", + "bbox": [ + 0.564, + 0.743, + 0.892, + 0.786 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {f e a t}} = \\frac {1}{2 N} \\sum_ {i = 0} ^ {\\mathcal {P}} \\left(F _ {i} ^ {T} - \\phi \\left(F _ {i} ^ {S}\\right)\\right) ^ {2}, \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.892, + 0.869 + ], + "angle": 0, + "content": "where \\(\\mathcal{P}\\) indicates the total number of features in FPN and \\(\\mathrm{N} = \\mathrm{C_iH_iW_i}\\). \\(C_i, H_i, W_i\\) represent the channel number, height, and width for feature map \\(F_{i}^{*}\\). \\(\\phi\\) is a convolutional layer with kernel size \\(1\\times 1\\) to align the channel dimension between the \\(F^T\\) and \\(F^{S}\\)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "As discussed above, to further enhance KD distillation dense visual predictions, we introduce the masked autoen" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6386" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.121 + ], + "angle": 0, + "content": "coding scheme into KD learning. In this manner, the distillation of the features can be formulated as:" + }, + { + "type": "equation", + "bbox": [ + 0.097, + 0.129, + 0.47, + 0.17 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {f e a t}} = \\frac {1}{2 N} \\sum_ {i = 0} ^ {\\mathcal {P}} \\left(F _ {i} ^ {T} - f _ {\\text {d e c}} \\left(\\phi \\left(F _ {i} ^ {S}\\right), \\mathcal {T} _ {\\text {m a s k}}\\right)\\right) ^ {2}, \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.18, + 0.469, + 0.225 + ], + "angle": 0, + "content": "where \\( f_{dec} \\) is the proposed adaptive decoder module with spatial alignment module, stacked transformer decoder layers, and spatial recovery module. \\( T_{mask} \\) is the mask token." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.226, + 0.471, + 0.557 + ], + "angle": 0, + "content": "The overall architecture of MKD is shown in Fig. 3. Firstly, given an image with \\( H \\times W \\), a binary mask map \\( \\mathcal{M} \\) with the element number \\( N = \\frac{H}{s} \\times \\frac{W}{s} \\) is randomly sampled with a given masking ratio. \\( s \\) is the down-sampled factor of the mask map and we set it to 32 in our experiments. We progressively upsample the mask to align its resolution to the output of each convolutional stage in the student's backbone. Using the student as an encoder, the masked images are then sent to it and the masked residual blocks in each masked convolutional stage are conducted to leave the masked area unprocessed by the backbone in the forward process. Finally, the masked feature maps generated by FPN will be sent to an adaptive decoder module where a spatial alignment module (SAM) is introduced to operate on the multi-scale features, along with a decoder and spatial recovery module (SRM) that reconstructs the latent representations with mask tokens. This learning manner is supervised by forcing the student's output of the adaptive decoder to imitate the teacher's output. Even if we mask random patches of the input image, with the assistance of MKD, the student model can still infer the features of the invisible patches." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.575, + 0.332, + 0.59 + ], + "angle": 0, + "content": "3.1.1 Masking in the Image Space." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.599, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Following ViT [8] and MAE [13], we first divide the input image into regular non-overlapping image patches, and then randomly generate a binary mask according to the given masking ratio. The masked area in the input image keeps unseen to the student model. We simply refer to this as \"random masking\". Notice that the random masking strategy follows a uniform distribution, which eliminates the potential center bias. The mask is illustrated in Fig. 3, which is a schematic gram, and the real masked image is shown in Fig. 1. Different from ViT, the convolutional neural network is designed with a pyramid scheme where different convolutional stages are set with different stride factors. This leads to multiple different spatial resolutions in the student's forward propagation. To make consistent with this, after generating a mask with resolution \\(\\frac{H}{32} \\times \\frac{W}{32}\\) for the late stage in the student, we progressively upsample the mask to larger resolutions in early convolutional stages as shown in Fig. 3. Introducing random masking to knowledge distillation can create a task that cannot be easily solved by directly performing the pixel-to-pixel spatial matching supervision." + }, + { + "type": "image", + "bbox": [ + 0.532, + 0.089, + 0.865, + 0.38 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.39, + 0.893, + 0.435 + ], + "angle": 0, + "content": "Figure 4: Illustration of the adaptive decoder. The inputs are the corresponding mask and feature maps from the teacher's FPN and the student's FPN." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.447, + 0.673, + 0.46 + ], + "angle": 0, + "content": "3.1.2 Masked Encoder." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.473, + 0.893, + 0.82 + ], + "angle": 0, + "content": "In our MKD, the student backbone is used as the encoder to process the masked input image. To ensure that the network only operates on the visible patches and reconstructs only from the neighboring ones, previously masked auto-encoders such as MAE proposed to forward only the visible tokens into the encoder. However, this method cannot be used directly in convolutional networks since we need to preserve the spatial dimension of the image. Following ConvMAE [10], we adopt the masked convolution to solve this problem, which is commonly used in image inpainting [23] and sparse feature extraction [27] to process the incomplete input information. More specifically, masked convolutions are used in all blocks for each stage in the whole student so that the masked regions are not involved in the encoding process. The operation of masked convolution is shown in Fig. 3, where the input feature maps from the previous layer are masked firstly by performing the Hadamard product with the mask map. This can effectively avoid the confusing feature interaction between masked and visible regions. In this way, the decoder can only speculate based on the information of adjacent image blocks during reconstruction. We assume that this will help the encoder learn more expressive and content-rich features." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.845, + 0.681, + 0.86 + ], + "angle": 0, + "content": "3.1.3 Adaptive Decoder." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "The input to the adaptive decoder is the multi-scale masked feature maps of the student followed by a \\(1 \\times 1\\) convolu" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6387" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.56 + ], + "angle": 0, + "content": "tion layer to align the channel number. The masked sizes are different in these multi-scale features, which leads to inconsistent feature reconstruction. To alleviate this, we introduce a simple spatial alignment module (SAM) to align them to the same spatial resolution (\\(\\frac{1}{32}\\) of the input image size in our experiments). As shown in Fig. 4, this is implemented by convolutional layer with stride \\(p\\) or upsampling the spatial resolution by a factor of \\(\\frac{1}{p}\\) (using nearest neighbor upsampling for simplicity), where scaling factor \\(p = H_i / \\frac{H}{32} = W_i / \\frac{W}{32}\\) is the multiplier to the target size. And then, a specific mask token is initialized for each feature scale and then replicated multiple times to replace the features in the masked area. See Fig. 3. Each mask token is a learned vector and is not shared between different feature scales. Different from the fixed input size in the classification task, the input size of the image is flexible, and this requires the same flexible positional embedding generation. We conduct the position encoding in an absolute scale, e.g., \\(28 \\times 28\\), and adaptively interpolate its resolution according to the input image size. We then add the positional embeddings to all tokens in each feature scale and send them to a series of transformer blocks to perform the feature reconstruction task. The final outputs of the transformer blocks are then restored to the original multi-scale resolutions via the spatial recovery module (SRM). In the SRM, we adopt a linear layer to change the channel numbers to \\(p^2 \\times C_i^T\\) (\\(p\\) is the same scaling factor used in SAM) and further reshape into the same size as \\(F_i^T\\). The output of SRM is forced to imitate the teacher's output and learns to reconstruct the missing feature. Note that the adaptive decoder is only used during training to perform the masked KD task." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.563, + 0.265, + 0.578 + ], + "angle": 0, + "content": "3.1.4 Distillation Target." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.585, + 0.47, + 0.661 + ], + "angle": 0, + "content": "Denote the output of SRM as \\(\\hat{F}_i^S\\in \\mathbb{R}^{C_i^T\\times H_i\\times W_i}\\) where \\(i\\) indicates the feature index in FPN and \\(C_i^T,H_i,W_i\\) indicate the channel number, height and width of the corresponding feature. The feature-based distillation loss can be formulated as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.152, + 0.667, + 0.47, + 0.709 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {f e a t}} = \\frac {1}{2 N} \\sum_ {i = 0} ^ {\\mathcal {P}} \\left(F _ {i} ^ {T} - \\hat {F} _ {i} ^ {S}\\right) ^ {2}, \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.714, + 0.47, + 0.805 + ], + "angle": 0, + "content": "where \\(\\mathcal{P}\\) indicates the total number of features in FPN and \\(\\mathrm{N} = \\mathrm{C_iH_iW_i}\\). \\(\\hat{F}_i^S\\) is the output of \\(f_{dec}(\\phi (F_i^S),\\mathcal{T}_{mask})\\) in Eq (2). Following the state-of-the-art feature-based distillation method FGD [40], we introduce the global distillation loss \\(\\mathcal{L}_{global}\\) to assist the distillation learning, which can be formulated as:" + }, + { + "type": "equation", + "bbox": [ + 0.138, + 0.809, + 0.469, + 0.85 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {g l o b a l}} = \\sum_ {i = 0} ^ {\\mathcal {P}} \\left(R \\left(F _ {i} ^ {T}\\right) - R \\left(\\hat {F} _ {i} ^ {S}\\right)\\right) ^ {2}, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.47, + 0.901 + ], + "angle": 0, + "content": "where \\(R\\) denotes GCBlock in FGD. Note that before computing \\(\\mathcal{L}_{feat}\\) and \\(\\mathcal{L}_{global}\\) we have \\(F^S\\) and \\(F^T\\) pass a layer normalization operation as well before MSE loss." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.893, + 0.166 + ], + "angle": 0, + "content": "To summarize, the overall training loss of the proposed MKD includes (a) task loss \\( L_{task} \\), e.g., classification loss and regression loss in object detection; (b) feature-based distillation loss \\( L_{feat} \\) and \\( L_{global} \\). It can be formulated as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.572, + 0.178, + 0.892, + 0.196 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\text {t a s k}} + \\lambda \\mathcal {L} _ {\\text {f e a t}} + \\gamma \\mathcal {L} _ {\\text {g l o b a l}} \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.206, + 0.894, + 0.251 + ], + "angle": 0, + "content": "where \\(\\lambda\\) and \\(\\gamma\\) are the weights to balance the distillation losses. The total distillation process is model-agnostic, so it works well with a variety of different structures." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.26, + 0.618, + 0.274 + ], + "angle": 0, + "content": "3.2. Discussion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.283, + 0.893, + 0.418 + ], + "angle": 0, + "content": "Feature-based distillation methods [29, 4, 41], such as hint-based [29, 1], attention-based [45, 40], and instance-based [34, 7, 17], have achieved superior performance improvement. They usually make the student imitate the teacher's output given fully visible image input and design different principles to extract the task-aware knowledge to guide the student's learning. But the redundant information in the teacher's feature hinders the complete knowledge learning of the student." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.419, + 0.895, + 0.676 + ], + "angle": 0, + "content": "As shown in Fig. 5, MGD [41] introduces the feature masking scheme to enhance the feature learning process by partially masking pixels in the feature maps from student's FPN. However, the information in the masked part has already been leaked during the forward process of the full image in the backbone. Thus, when minimizing KD loss, the effect of MGD is divided into two parts. First, since each adjacent pixel of the masked pixel already contains the information of the masked pixel, in the process of pushing student and teacher pair closer together, MGD extracts the masked feature from the leaked information in adjacent pixels and uses convolution to restore it. Second, the pixels around the masked pixels are pushed closer to the corresponding teacher. The effect of MGD is therefore dispersed, and even with the adaptive decoder proposed in our MKD, MGD is still not able to establish the connection between the masked and unmasked area as shown in Tab. 1." + }, + { + "type": "image", + "bbox": [ + 0.536, + 0.686, + 0.86, + 0.827 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.507, + 0.837, + 0.884, + 0.853 + ], + "angle": 0, + "content": "Figure 5: Comparison of different distillation paradigms." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.894, + 0.901 + ], + "angle": 0, + "content": "Different from all these paradigms, MKD introduces a global decoder to learn the relationship between the masked" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6388" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.114, + 0.089, + 0.438, + 0.142 + ], + "angle": 0, + "content": "
MethodmAPAP50AP75
original MGD [41]36.655.139.1
MGD + decoder in our MKD36.655.039.1
" + }, + { + "type": "table_caption", + "bbox": [ + 0.08, + 0.153, + 0.465, + 0.168 + ], + "angle": 0, + "content": "Table 1: Study on the decoder with Retina Res101-Res18." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.177, + 0.47, + 0.448 + ], + "angle": 0, + "content": "area and its surroundings, shown in Fig. 5, promoting the learning of complete knowledge in teacher by KD. MKD masks information in the image space throughout the distillation process, which guarantees that the masked area is completely invisible to the student. Since there is no additional information leakage, MKD more strongly pushes the features of the teacher and the student closer during distillation. Moreover, we visualize the self-attention in the transformer decoder blocks in Fig. 6. To restore the feature of the unseen masked region, the student network is driven to fully learn corresponding knowledge from the adjacent areas. Thus, the feature imitation process is accordingly enhanced. To better understand this, we illustrate the L2 distance between the teacher's and student's features in the adjacent regions in Fig. 2. Our MKD can further enhance the student's learning and demonstrates superior improvement over the previous KD paradigms as shown in Tab. 3 and Tab. 2." + }, + { + "type": "image", + "bbox": [ + 0.118, + 0.45, + 0.43, + 0.504 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.515, + 0.468, + 0.546 + ], + "angle": 0, + "content": "Figure 6: The visualization of attention in decoder blocks. The square in red denotes the query." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.573, + 0.209, + 0.59 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.599, + 0.468, + 0.779 + ], + "angle": 0, + "content": "In order to evaluate the performance of our proposed method on object detection tasks, we first conduct experiments on the MS COCO dataset [22], which consists of 80 object categories and over \\(120\\mathrm{k}\\) images in total. We use \\(120\\mathrm{k}\\) images for training and \\(5\\mathrm{k}\\) images for testing, following the most common setting. We take mean average precision (mAP) as the evaluation metric of all the detectors. As for the semantic segmentation task, we evaluate our distillation method on the Cityscapes dataset [6] with \\(5\\mathrm{k}\\) high-quality images and evaluate the performance with mean Intersection-over-Union (mIoU). The shown results are the average value of three runs." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Implementation Details. We train the student models with a batch size of 16 for 24 epochs (known as a \\(2 \\times\\) schedule). The initial learning rate is set by 0.01 for one-stage detectors and 0.02 for two-stage detectors. We reduce the learning rate by \\(0.1 \\times\\) at the 16th and 21st epochs. We adopt an early-stop mask strategy in the last 2 epochs, in which we set the masking ratio as 0.2 with a learning rate of 0.001 and without supervision from the teacher. This follows the co" + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.088, + 0.895, + 0.348 + ], + "angle": 0, + "content": "
MethodSchedulemAPAP50AP75
RetinaNet-ResX101(T)2x41.060.944.0
RetinaNet-Res50(S)2x37.456.739.6
FKD [45]2x39.6 (+2.2)58.842.1
FGD [40]2x40.4 (+3.0)59.943.3
MGD [41]2x40.7 (+3.3)59.442.8
MGD* [41]2x41.0 (+3.6)60.744.0
ours2x41.1 (+3.7)60.644.0
ours*2x41.5 (+4.1)61.144.3
RetinaNet-Res101(T)2x38.158.340.9
RetinaNet-MBV2(S)2x31.048.932.7
GID [7]2x33.5 (+2.5)51.935.5
FGD [40]2x35.6 (+4.6)53.838.1
MGD [41]2x35.5 (+4.5)
ours2x36.0 (+5.0)54.538.1
RetinaNet-Swin-s(T)1x39.760.142.2
RetinaNet-Swin-t(S)1x37.257.439.1
FGD [40]1x38.6 (+1.4)58.640.9
F=MGD [41]1x38.1 (+0.9)
ours1x39.3 (+2.1)59.541.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.358, + 0.892, + 0.404 + ], + "angle": 0, + "content": "Table 2: Results on COCO dataset with large backbones and swim transformer backbones [26]. T and S denote the teacher and the student, respectively." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.413, + 0.892, + 0.444 + ], + "angle": 0, + "content": "sine schedule down to 0. In this way, the input distribution of the whole image is consistent with the test image." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.444, + 0.892, + 0.61 + ], + "angle": 0, + "content": "We use SGD as the optimizer and set the momentum and weight decay by 0.9 and 0.0001, respectively. We use the masking ratio of 0.1 by default and set the size of masked patches by 32. The number of adaptive decoder layers is 4. Transformer blocks in the decoder have 256 channels with a head number of 8, and the mlp ratio is set to be 8. The loss weight in Eq. 5 are set to be \\(\\{\\lambda = 3,\\gamma = 3e - 6\\}\\) in single-stage detectors, \\(\\{\\lambda = 3,\\gamma = 3e - 7\\}\\) in two-stage detectors, and \\(\\{\\lambda = 7,\\gamma = 0\\}\\) in segmentation. All the experiments are conducted on 8 GPUs with mmdetection [2] and mmsegmentation [5] on PyTorch." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.621, + 0.638, + 0.635 + ], + "angle": 0, + "content": "4.1. Main Results" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.644, + 0.892, + 0.9 + ], + "angle": 0, + "content": "Object detection. To verify the effectiveness of the MKD, we conduct experiments on popular detectors, i.e., RetinaNet [21], Faster R-CNN [28] and Reppoints [43] with various backbones, and the results are shown in Tab. 3 and Tab. 2. We can observe that the proposed MKD can consistently improve the student model by more than 2.5 mAP. For example, the Faster R-CNN with ResNet 50 can achieve \\(41.1\\mathrm{mAP}\\) when mimicking Faster R-CNN with ResNet 101 with MKD, which even surpasses the teacher. We further compare our method with the state-of-the-art for detection distillation under fair settings. Our MKD surpasses FGD [40] and MGD [41] on various student-teacher pairs. When distilling the RetinaNet-Res50 model with RetinaNet-ResX101 as the teacher, MKD transcends MGD with 0.4 on mAP and 1.2 on AP50. A similar trend can be observed when we choose smaller students like ResNet 18 as the backbone." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6389" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.115, + 0.088, + 0.861, + 0.584 + ], + "angle": 0, + "content": "
Method (The default training schedule is 2x)mAPAP50AP75APsAPmAPI
RetinaNet-Res101(Teacher network)38.958.041.521.042.852.4
RetinaNet-Res18(Student network)33.451.835.116.935.644.9
FKD [45]35.9 (+2.5)54.438.017.939.149.1
FGD [40]36.2 (+2.8)54.738.619.540.148.4
MGD [41]36.6 (+3.2)55.139.119.540.350.7
ours37.3 (+3.9)56.139.919.041.051.6
ours*(with the parameter inheriting scheme [17])37.5 (+4.1)56.039.919.441.551.2
RetinaNet-Res101(Teacher network)38.958.041.521.042.852.4
RetinaNet-Res50(Student network)37.456.739.620.040.749.7
GID [7]39.1 (+1.7)59.042.322.843.152.3
FGD [40]39.6 (+2.2)58.542.522.943.753.6
MGD [41]39.5 (+2.1)58.542.221.343.653.4
ours39.9 (+2.5)59.042.722.343.953.3
ours*(with the parameter inheriting scheme [17])40.2 (+2.8)59.343.022.344.454.0
FasterRCNN-Res101(Teacher network)39.860.143.322.543.652.8
FasterRCNN-Res50(Student network)38.459.042.021.542.150.3
FGFI [34]39.3 (+0.9)59.842.922.542.352.2
GID [7]40.2 (+1.8)60.743.822.744.053.2
FGD [40]40.4 (+2.0)60.744.322.844.553.5
MGD [41]40.1 (+1.7)60.243.622.944.253.3
ours41.0 (+2.6)61.544.723.545.553.4
ours*(with the parameter inheriting scheme [17])41.1 (+2.7)61.544.824.445.154.3
FCOS-Res101(Teacher network)40.860.044.024.244.352.4
FCOS-Res50(Student network)38.557.741.021.942.848.6
GID [7]42.0 (+3.5)60.445.525.645.854.2
FGD [40]42.1 (+3.6)--27.046.054.6
MGD [41]42.2(+3.7)60.945.326.646.354.7
ours42.5 (+4.0)61.246.126.646.854.6
ours*(with the parameter inheriting scheme [17])43.1 (+4.6)61.746.727.347.155.1
Reppoints-ResX101(Teacher network)44.265.547.826.248.458.5
Reppoints-Res50(Student network)38.659.641.622.542.250.4
FKD [45]40.6 (+2.0)61.743.823.444.653.0
FGD [40]41.3 (+2.7)--24.545.254.0
MGD [41]41.8 (+3.2)62.844.824.245.855.6
MGD [41]*(with the parameter inheriting scheme [17])42.3 (+3.7)63.345.424.446.255.9
ours42.2 (+3.6)63.045.624.346.455.7
ours*(with the parameter inheriting scheme [17])43.0 (+4.4)63.846.124.447.257.1
" + }, + { + "type": "table_caption", + "bbox": [ + 0.096, + 0.593, + 0.872, + 0.609 + ], + "angle": 0, + "content": "Table 3: Object detection performance of our proposed MKD with various teacher-student pairs on the COCO dataset." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.635, + 0.471, + 0.756 + ], + "angle": 0, + "content": "Moreover, our method can benefit from a longer training schedule. For example, when training for 36 epochs, our MKD can further improve the performance of the student model over \\(4.0\\mathrm{mAP}\\), which surpasses other methods by a larger margin than that for 12 epochs. This demonstrates that introducing a masked autoencoder into knowledge distillation can help the student avoid early saturation and benefit more from the distillation process." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Semantic segmentation. Our MKD can be easily transferred to segmentation tasks such as semantic segmentation, and we conduct knowledge distillation experiments to show the generality of the proposed method. We choose PspNet-Res101 [47] as the teacher to distill PspNet-Res18 and DeepLabV3-Res18 [3]. As shown in Tab. 5, our method improves the PspNet-Res18 model with \\(4.85\\mathrm{mIoU}\\), which greatly fills the gap between the student and the teacher. Also, MKD surpasses MGD and other methods by a signif" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.635, + 0.892, + 0.664 + ], + "angle": 0, + "content": "icant margin, which verifies the effectiveness and generality of our method." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.667, + 0.892, + 0.756 + ], + "angle": 0, + "content": "Image classification. Since the core bottleneck is particularly prominent in fine-grained visual tasks that rely on spatial localization information, we mainly evaluate our methods on them. We also present the result of MKD on the classification task in Tab. 6, which further verifies its effectiveness." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.77, + 0.655, + 0.788 + ], + "angle": 0, + "content": "4.2. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Masking ratio. We first examine the influence of different masking ratios on the performance shown in Fig. 7. Large masking ratios benefit more from longer training schedules. For example, a masking ratio of 0.1 achieves the best under a 1x schedule, while the best one changes to 0.3 under a 3x schedule. This is because a larger masking ratio introduces more difficulty to the distillation process and needs more" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6390" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.104, + 0.102, + 0.29, + 0.17 + ], + "angle": 0, + "content": "
Patch SizemAPAP50AP75
Baseline37.456.739.6
1639.859.242.5
3239.959.342.5
6439.859.042.7
" + }, + { + "type": "table_caption", + "bbox": [ + 0.141, + 0.173, + 0.243, + 0.185 + ], + "angle": 0, + "content": "(a) The patch size." + }, + { + "type": "table", + "bbox": [ + 0.313, + 0.102, + 0.534, + 0.171 + ], + "angle": 0, + "content": "
ResolutionmAPAP50AP75
w/o SAM, SRMOOM--
[H/16, W/16]38.958.041.6
[H/32, W/32]39.959.342.5
[H/64, W/64]39.759.142.2
" + }, + { + "type": "table_caption", + "bbox": [ + 0.32, + 0.174, + 0.51, + 0.186 + ], + "angle": 0, + "content": "(b) The aligned resolution in SAM." + }, + { + "type": "table", + "bbox": [ + 0.542, + 0.102, + 0.693, + 0.171 + ], + "angle": 0, + "content": "
λmAPAP50AP75
039.658.842.5
139.959.242.8
339.959.342.5
539.759.042.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.55, + 0.173, + 0.676, + 0.185 + ], + "angle": 0, + "content": "(c) The loss weights \\(\\lambda\\)" + }, + { + "type": "table", + "bbox": [ + 0.72, + 0.102, + 0.871, + 0.17 + ], + "angle": 0, + "content": "
γmAPAP50AP75
039.759.042.6
1e-639.758.942.2
3e-639.959.342.5
5e-639.859.242.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.729, + 0.173, + 0.855, + 0.186 + ], + "angle": 0, + "content": "(d) The loss weights \\(\\gamma\\)" + }, + { + "type": "table", + "bbox": [ + 0.107, + 0.199, + 0.316, + 0.267 + ], + "angle": 0, + "content": "
DepthmAPAP50AP75
Baseline37.456.739.6
239.658.742.4
439.959.342.5
839.859.042.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.097, + 0.271, + 0.317, + 0.283 + ], + "angle": 0, + "content": "(e) The depth of the adaptive decoder \\(N\\)" + }, + { + "type": "table", + "bbox": [ + 0.356, + 0.199, + 0.586, + 0.267 + ], + "angle": 0, + "content": "
Masked ConvolutionmAPAP50AP75
Baseline37.456.739.6
w/o39.658.842.5
w/39.959.342.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.39, + 0.271, + 0.543, + 0.282 + ], + "angle": 0, + "content": "(f) The masked convolution." + }, + { + "type": "table", + "bbox": [ + 0.626, + 0.199, + 0.868, + 0.268 + ], + "angle": 0, + "content": "
Mask StrategymAPAP50AP75
Baseline37.456.739.6
Random39.959.342.5
Grid37.857.040.2
Block39.759.242.7
" + }, + { + "type": "table_caption", + "bbox": [ + 0.673, + 0.271, + 0.812, + 0.283 + ], + "angle": 0, + "content": "(g) The masking strategy." + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.295, + 0.892, + 0.34 + ], + "angle": 0, + "content": "Table 4: Ablation study on the MKD design with RetinaNet-ResNet50 as student and RetinaNet-ResNeXt101 as a teacher under 1x training schedule. If not specified, the patch size is 32, \\(\\lambda = 3\\), \\(\\gamma = 3e - 6\\), the decoder has a depth of 4, and the mask is randomly sampled." + }, + { + "type": "table", + "bbox": [ + 0.133, + 0.347, + 0.419, + 0.569 + ], + "angle": 0, + "content": "
MethodinputsizemIoU
PspNet-Res101(T)512x102478.34
PspNet-Res18(S)512x51269.85
SKDS [25]512x51272.70
CWD [30]512x51273.53
MGD [41]512x51273.63
MGD* [41]512x51274.10
ours512x51273.99
ours*512x51274.70
PspNet-Res101(T)512x102478.34
DeepLabV3-Res18(S)512x51273.20
SKDS [25]512x51273.87
CWD [30]512x51275.93
MGD [41]512x51276.02
MGD* [41]512x51276.31
ours512x51276.14
ours*512x51276.63
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.58, + 0.468, + 0.611 + ], + "angle": 0, + "content": "Table 5: Semantic segmentation result on Cityscape dataset. * means adopting an extra logits loss from CWD [30]." + }, + { + "type": "table", + "bbox": [ + 0.153, + 0.617, + 0.398, + 0.713 + ], + "angle": 0, + "content": "
MethodTop-1Top-5
ResNet-34(T)73.6291.59
ResNet-18(S)69.9089.43
FitNet [29]71.5090.27
SRRL [39]71.7390.60
MGD [41]71.8090.40
Ours72.0190.43
" + }, + { + "type": "table_caption", + "bbox": [ + 0.086, + 0.724, + 0.46, + 0.74 + ], + "angle": 0, + "content": "Table 6: The performance of classification on ImageNet." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.75, + 0.383, + 0.765 + ], + "angle": 0, + "content": "optimization steps for the student to converge." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Masked convolution. To keep the masked patches not affected by others in the convolution block, we introduce the masked convolution in our MKD, and the results of ablation on masked convolution are shown in Tab. 4f. Removing masked convolution from MKD will lead to a reduction of \\(0.3\\mathrm{mAP}\\), which is still better than that of the baseline. This demonstrates that the masking operation indeed hinders the optimization of convolution blocks, and adopting masked convolution can effectively alleviate this issue." + }, + { + "type": "image", + "bbox": [ + 0.578, + 0.363, + 0.793, + 0.488 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.492, + 0.892, + 0.553 + ], + "angle": 0, + "content": "Figure 7: Illustration of the performance improvement of different masking ratios under different schedules. It appears that MKD (green) brings the greatest boost to the baseline (36.5mAP)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.582, + 0.892, + 0.702 + ], + "angle": 0, + "content": "Mask patch size. Here we examine how the masked patch size influences the distillation process. As shown in Tab. 4a, a patch size of 32 performs the best than other options. A smaller patch will lead to the confusing assignment of masked position in the last stage, which leads to inferior performance. On the contrary, using a larger patch size may distort the objects too much and make the edge vague. So we use a masked patch size of 32 by default in our work." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.703, + 0.892, + 0.809 + ], + "angle": 0, + "content": "SAM and SRM. We compare different aligned resolutions in SAM, and the results are shown in Tab. 4b. The training process appears to be out of memory(OOM) without spatial alignment operation, indicating that SAM and SRM are important in reducing computation and memory. We further found that setting the target resolution as \\(\\frac{H}{32} \\times \\frac{W}{32}\\) performs the best because it is the same size as the masked patches." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Mask sampling strategies. Here we examine the influence of different masking strategies, e.g., masking randomly, masking in grids, and masking by block. Recent masked image modeling works show that random strategy works the best, and we observe a similar trend in our MKD. Note that to prevent the student network from learning the mask pat" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "6391" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.137 + ], + "angle": 0, + "content": "tern, it is necessary to use a global random mask. As shown in Tab. 4g, random masking surpasses other ways and is selected in other experiments in this paper." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.138, + 0.47, + 0.301 + ], + "angle": 0, + "content": "Adaptive decoder design. Adaptive decoder helps to reconstruct masked features from visible ones and is an important module in MKD. We choose different numbers of decoder layers and examine their effects on distillation performance. As shown in Tab. 4e, four layers perform the best. Due to the feature dimension and length of the sequence, we use four layers by default. Objects of different scales correspond to different feature levels of FPN, so we use unshared tokens for the reconstruction. While shared tokens cause a performance drop from \\(37.3\\mathrm{mAP}\\) to \\(37.0\\mathrm{mAP}\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.303, + 0.471, + 0.499 + ], + "angle": 0, + "content": "Loss weight. In Eq. 5, we use two hyper-parameters \\(\\lambda\\) and \\(\\gamma\\) to balance the distillation loss, and we conduct ablation studies to investigate their sensitivities of them. From Tab. 4d and 4c, it can be seen that the performance of the student model is not sensitive to the choices of \\(\\lambda\\) and \\(\\gamma\\), as the gap between the worst and the best is within \\(0.2\\mathrm{mAP}\\). Note that \\(L_{feat}\\) and \\(L_{global}\\) are both distillation losses to calculate the similarity between the reconstructed output of the decoder \\(\\hat{F}^S\\) and teacher feature \\(F^T\\). The main difference is that \\(L_{feat}\\) directly calculates MSE, and \\(L_{global}\\) goes through a GCblock. Hence, the performance drop is small when \\(\\lambda = 0\\) or \\(\\gamma = 0\\), as MKD already works when using either of the loss alone." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.513, + 0.196, + 0.529 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.539, + 0.47, + 0.735 + ], + "angle": 0, + "content": "In this paper, we propose a new distillation paradigm Masked Knowledge Distillation (MKD), which introduces the masked autoencoding scheme to enhance the knowledge distillation process. MKD takes the masked image as input and predicts the whole feature map that is used to imitate the corresponding feature of the teacher network. By forcing the student network to learn the knowledge of the nearby region of the masked part to recover the full feature, the student can better transfer the corresponding information from the teacher, which helps to excavate the potential of the small student network. Extensive experimental results on various fine-grained visual tasks show its power in enhancing the improvement of knowledge distillation." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.749, + 0.238, + 0.766 + ], + "angle": 0, + "content": "Acknowledgement" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.773, + 0.469, + 0.835 + ], + "angle": 0, + "content": "This work was partly supported by the National Natural Science Foundation of China (Grant No. 61991451) and the Shenzhen Science and Technology Program (JCYJ20220818101001004)." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.848, + 0.174, + 0.864 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.085, + 0.873, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[1] Guobin Chen, Wongun Choi, Xiang Yu, Tony Han, and Manmohan Chandraker. Learning efficient object detection mod" + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.119 + ], + "angle": 0, + "content": "els with knowledge distillation. In NIPS, pages 742-751, 2017. 2, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.122, + 0.894, + 0.19 + ], + "angle": 0, + "content": "[2] Kai Chen, Jiaqi Wang, Jiangmiao Pang, Yuhang Cao, Yu Xiong, Xiaoxiao Li, Shuyang Sun, Wansen Feng, Ziwei Liu, Jiarui Xu, et al. Mmdetection: Open mmlab detection toolbox and benchmark. arXiv preprint arXiv:1906.07155, 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.192, + 0.895, + 0.246 + ], + "angle": 0, + "content": "[3] Liang-Chieh Chen, George Papandreou, Florian Schroff, and Hartwig Adam. Rethinking atrous convolution for semantic image segmentation. arXiv preprint arXiv:1706.05587, 2017. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.249, + 0.895, + 0.289 + ], + "angle": 0, + "content": "[4] Pengguang Chen, Shu Liu, Hengshuang Zhao, and Jiaya Jia. Distilling knowledge via knowledge review. In CVPR, pages 5008-5017, 2021. 1, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.291, + 0.895, + 0.347 + ], + "angle": 0, + "content": "[5] MMSegmentation Contributors. Mmsegmentation: Openmmlab semantic segmentation toolbox and benchmark. https://github.com/open-mmlab/mmsegmentation, 2020.6" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.349, + 0.895, + 0.417 + ], + "angle": 0, + "content": "[6] Marius Cordts, Mohamed Omran, Sebastian Ramos, Timo Rehfeld, Markus Enzweiler, Rodrigo Benenson, Uwe Franke, Stefan Roth, and Bernt Schiele. The cityscapes dataset for semantic urban scene understanding. In CVPR, pages 3213-3223, 2016. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.419, + 0.895, + 0.473 + ], + "angle": 0, + "content": "[7] Xing Dai, Zeren Jiang, Zhao Wu, Yiping Bao, Zhicheng Wang, Si Liu, and Erjin Zhou. General instance distillation for object detection. In CVPR, pages 7842-7851, 2021. 1, 3, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.476, + 0.892, + 0.544 + ], + "angle": 0, + "content": "[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In ICLR, 2020. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.546, + 0.892, + 0.587 + ], + "angle": 0, + "content": "[9] Kaiwen Duan, Song Bai, Lingxi Xie, Honggang Qi, Qingming Huang, and Qi Tian. Centernet: Keypoint triplets for object detection. In ICCV, pages 6569-6578, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.589, + 0.892, + 0.63 + ], + "angle": 0, + "content": "[10] Peng Gao, Teli Ma, Hongsheng Li, Jifeng Dai, and Yu Qiao. Convmae: Masked convolution meets masked autoencoders. arXiv preprint arXiv:2205.03892, 2022. 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.632, + 0.892, + 0.699 + ], + "angle": 0, + "content": "[11] Kunyang Han, Yong Liu, Jun Hao Liew, Henghui Ding, Yunchao Wei, Jiajun Liu, Yitong Wang, Yansong Tang, Yujiu Yang, Jiashi Feng, et al. Global knowledge calibration for fast open-vocabulary segmentation. arXiv preprint arXiv:2303.09181, 2023. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.702, + 0.892, + 0.743 + ], + "angle": 0, + "content": "[12] Song Han, Jeff Pool, John Tran, and William Dally. Learning both weights and connections for efficient neural network. NIPS, 28, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.745, + 0.892, + 0.786 + ], + "angle": 0, + "content": "[13] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollar, and Ross Girshick. Masked autoencoders are scalable vision learners. In CVPR, pages 16000-16009, 2022. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.788, + 0.892, + 0.815 + ], + "angle": 0, + "content": "[14] Kaiming He, Georgia Gkioxari, Piotr Dólar, and Ross Girshick. Mask r-cnn. In ICCV, pages 2961-2969, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.817, + 0.892, + 0.858 + ], + "angle": 0, + "content": "[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778, 2016. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.86, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[16] Geoffrey Hinton, Oriol Vinyals, and Jeff Dean. Distilling the knowledge in a neural network. Computer Science, 14(7):38-39, 2015. 1, 3" + }, + { + "type": "list", + "bbox": [ + 0.502, + 0.093, + 0.895, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6392" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.146 + ], + "angle": 0, + "content": "[17] Zijian Kang, Peizhen Zhang, Xiangyu Zhang, Jian Sun, and Nanning Zheng. Instance-conditional knowledge distillation for object detection. NIPS, 34:16468-16480, 2021. 1, 3, 5, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.15, + 0.469, + 0.191 + ], + "angle": 0, + "content": "[18] Quanquan Li, Shengying Jin, and Junjie Yan. Mimicking very efficient network for object detection. In CVPR, pages 6356-6364, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.194, + 0.469, + 0.235 + ], + "angle": 0, + "content": "[19] Rundong Li, Yan Wang, Feng Liang, Hongwei Qin, Junjie Yan, and Rui Fan. Fully quantized network for object detection. In CVPR, pages 2810-2819, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.238, + 0.469, + 0.292 + ], + "angle": 0, + "content": "[20] Tsung-Yi Lin, Piotr Dólar, Ross Girshick, Kaiming He, Bharath Hariharan, and Serge Belongie. Feature pyramid networks for object detection. In CVPR, pages 2117-2125, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.295, + 0.469, + 0.337 + ], + "angle": 0, + "content": "[21] Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dólar. Focal loss for dense object detection. In ICCV, pages 2980-2988, 2017. 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.34, + 0.469, + 0.395 + ], + "angle": 0, + "content": "[22] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dálár, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In ECCV, pages 740-755. Springer, 2014. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.397, + 0.469, + 0.451 + ], + "angle": 0, + "content": "[23] Guilin Liu, Fitsum A Reda, Kevin J Shih, Ting-Chun Wang, Andrew Tao, and Bryan Catanzaro. Image inpainting for irregular holes using partial convolutions. In ECCV, pages 85-100, 2018. 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.454, + 0.469, + 0.509 + ], + "angle": 0, + "content": "[24] Wei Liu, Dragomir Anguelov, Dumitru Erhan, Christian Szegedy, Scott Reed, Cheng-Yang Fu, and Alexander C Berg. Ssd: Single shot multibox detector. In ECCV, pages 21-37. Springer, 2016. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.512, + 0.469, + 0.566 + ], + "angle": 0, + "content": "[25] Yifan Liu, Ke Chen, Chris Liu, Zengchang Qin, Zhenbo Luo, and Jingdong Wang. Structured knowledge distillation for semantic segmentation. In CVPR, pages 2604-2613, 2019. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.569, + 0.469, + 0.624 + ], + "angle": 0, + "content": "[26] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In ICCV, pages 10012-10022, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.627, + 0.469, + 0.668 + ], + "angle": 0, + "content": "[27] Mengye Ren, Andrei Pokrovsky, Bin Yang, and Raquel Urtasun. Sbnet: Sparse blocks network for fast inference. In CVPR, pages 8711-8720, 2018. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.671, + 0.469, + 0.712 + ], + "angle": 0, + "content": "[28] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. NIPS, 28, 2015. 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.715, + 0.469, + 0.768 + ], + "angle": 0, + "content": "[29] Adriana Romero, Nicolas Ballas, Samira Ebrahimi Kahou, Antoine Chassang, Carlo Gatta, and Yoshua Bengio. Fitnets: Hints for thin deep nets. arXiv preprint arXiv:1412.6550, 2014. 1, 3, 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.772, + 0.469, + 0.813 + ], + "angle": 0, + "content": "[30] Changyong Shu, Yifan Liu, Jianfei Gao, Zheng Yan, and Chunhua Shen. Channel-wise knowledge distillation for dense prediction. In ICCV, pages 5311-5320, 2021. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.816, + 0.469, + 0.856 + ], + "angle": 0, + "content": "[31] Mingxing Tan, Ruoming Pang, and Quoc V Le. Efficientdet: Scalable and efficient object detection. In CVPR, pages 10781-10790, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.859, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[32] Zhi Tian, Chunhua Shen, Hao Chen, and Tong He. Fcos: Fully convolutional one-stage object detection. In ICCV, pages 9627-9636, 2019. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[33] Jiahao Wang, Mingdeng Cao, Shuwei Shi, Baoyuan Wu, and Yujiu Yang. Attention probe: Vision transformer distillation in the wild. In ICASSP, pages 2220-2224. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.136, + 0.892, + 0.177 + ], + "angle": 0, + "content": "[34] Tao Wang, Li Yuan, Xiaopeng Zhang, and Jiashi Feng. Distilling object detectors with fine-grained feature imitation. In CVPR, pages 4933-4942, 2019. 1, 2, 3, 5, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.179, + 0.892, + 0.219 + ], + "angle": 0, + "content": "[35] Xinlong Wang, Rufeng Zhang, Tao Kong, Lei Li, and Chunhua Shen. Solov2: Dynamic and fast instance segmentation. NIPS, 33:17721-17732, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.221, + 0.892, + 0.262 + ], + "angle": 0, + "content": "[36] Yi Wei, Xinyu Pan, Hongwei Qin, Wanli Ouyang, and Junjie Yan. Quantization mimic: Towards very tiny cnn for object detection. In ECCV, pages 267-283, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.264, + 0.892, + 0.305 + ], + "angle": 0, + "content": "[37] Taiqiang Wu, Cheng Hou, Zhe Zhao, Shanshan Lao, Jiayi Li, Ngai Wong, and Yujiu Yang. Weight-inherited distillation for task-agnostic bert compression, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.307, + 0.892, + 0.36 + ], + "angle": 0, + "content": "[38] Xiang Xiang, Zhiyuan Wang, Shanshan Lao, and Baochang Zhang. Pruning multi-view stereo net for efficient 3d reconstruction. ISPRS Journal of Photogrammetry and Remote Sensing, 168:17-27, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.363, + 0.892, + 0.404 + ], + "angle": 0, + "content": "[39] Jing Yang, Brais Martinez, Adrian Bulat, Georgios Tzimiropoulos, et al. Knowledge distillation via softmax regression representation learning. ICLR, 2021. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.407, + 0.892, + 0.46 + ], + "angle": 0, + "content": "[40] Zhendong Yang, Zhe Li, Xiaohu Jiang, Yuan Gong, Zehuan Yuan, Danpei Zhao, and Chun Yuan. Focal and global knowledge distillation for detectors. In CVPR, pages 4643-4652, 2022. 1, 2, 3, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.463, + 0.892, + 0.504 + ], + "angle": 0, + "content": "[41] Zhendong Yang, Zhe Li, Mingqi Shao, Dachuan Shi, Zehuan Yuan, and Chun Yuan. Masked generative distillation. arXiv preprint arXiv:2205.01529, 2022. 3, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.506, + 0.892, + 0.547 + ], + "angle": 0, + "content": "[42] Zhendong Yang, Zhe Li, Ailing Zeng, Zexian Li, Chun Yuan, and Yu Li. Vitkd: Practical guidelines for vit feature knowledge distillation. arXiv preprint arXiv:2209.02432, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.549, + 0.892, + 0.589 + ], + "angle": 0, + "content": "[43] Ze Yang, Shaohui Liu, Han Hu, Liwei Wang, and Stephen Lin. Repoints: Point set representation for object detection. In ICCV, pages 9657-9666, 2019. 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.591, + 0.892, + 0.659 + ], + "angle": 0, + "content": "[44] Zhendong Yang, Ailing Zeng, Zhe Li, Tianke Zhang, Chun Yuan, and Yu Li. From knowledge distillation to self-knowledge distillation: A unified approach with normalized loss and customized soft labels. arXiv preprint arXiv:2303.13005, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.662, + 0.892, + 0.702 + ], + "angle": 0, + "content": "[45] Linfeng Zhang and Kaisheng Ma. Improve object detection with feature-based knowledge distillation: Towards accurate and efficient detectors. In ICLR, 2020. 1, 3, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.704, + 0.892, + 0.745 + ], + "angle": 0, + "content": "[46] Borui Zhao, Quan Cui, Renjie Song, Yiyu Qiu, and Jiajun Liang. Decoupled knowledge distillation. In CVPR, pages 11953-11962, 2022. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.747, + 0.892, + 0.788 + ], + "angle": 0, + "content": "[47] Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, and Jiaya Jia. Pyramid scene parsing network. In CVPR, pages 2881-2890, 2017. 7" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.788 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.515, + 0.957 + ], + "angle": 0, + "content": "6393" + } + ] +] \ No newline at end of file diff --git a/2023/Masked Autoencoders Are Stronger Knowledge Distillers/801459a1-6a61-45c0-b371-eb489abaf84f_origin.pdf b/2023/Masked Autoencoders Are Stronger Knowledge Distillers/801459a1-6a61-45c0-b371-eb489abaf84f_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..f4c6f3eb327759bd57805a02c732df1511d9bf3d --- /dev/null +++ b/2023/Masked Autoencoders Are Stronger Knowledge Distillers/801459a1-6a61-45c0-b371-eb489abaf84f_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:f676a22dca34386ed3218cc5770f8c98df1cb9d4341bc8a40480ca01b7316a6a +size 2583733 diff --git a/2023/Masked Autoencoders Are Stronger Knowledge Distillers/full.md b/2023/Masked Autoencoders Are Stronger Knowledge Distillers/full.md new file mode 100644 index 0000000000000000000000000000000000000000..9e44ee46ead9875bf4bc6bdf040c7f80eac73a21 --- /dev/null +++ b/2023/Masked Autoencoders Are Stronger Knowledge Distillers/full.md @@ -0,0 +1,309 @@ +# Masked Autoencoders Are Stronger Knowledge Distillers + +Shanshan Lao1* Guanglu Song2 Boxiao Liu2 Yu Liu2† Yujiu Yang1† +1Tsinghua Shenzhen International Graduate School, Tsinghua University +2Sensetime Research + +laoss21@mails.tsinghua.edu.cn, {songguanglu, liuboxiao}@sensetime.com +liuyuisanai@gmail.com, yang.yujiu@sz.tsinghua.edu.cn + +# Abstract + +Knowledge distillation (KD) has shown great success in improving student's performance by mimicking the intermediate output of the high-capacity teacher in fine-grained visual tasks, e.g. object detection. This paper proposes a technique called Masked Knowledge Distillation (MKD) that enhances this process using a masked autoencoding scheme. In MKD, random patches of the input image are masked, and the corresponding missing feature is recovered by forcing it to imitate the output of the teacher. MKD is based on two core designs. First, using the student as the encoder, we develop an adaptive decoder architecture, which includes a spatial alignment module that operates on the multi-scale features in the feature pyramid network (FPN) [20], a simple decoder, and a spatial recovery module that mimics the teacher's output from the latent representation and mask tokens. Second, we introduce the masked convolution in each convolution block to keep the masked patches unaffected by others. By coupling these two designs, we can further improve the completeness and effectiveness of teacher knowledge learning. We conduct extensive experiments on different architectures with object detection and semantic segmentation. The results show that all the students can achieve further improvements compared to the conventional KD. Notably, we establish the new state-of-the-art results by boosting RetinaNet ResNet-18, and ResNet-50 from 33.4 to 37.5 mAP, and 37.4 to 41.5 mAP, respectively. + +# 1. Introduction + +As fundamental tasks in computer vision, high-level visual predictions such as object detection, instance segmentation, and semantic segmentation have been widely used in various practical applications. In real-world scenarios, improving the performance of the deployable models is crucial. Improving the performance of a lightweight student + +![](images/88c66b86dd6bd0d387cdbabb322d17a69d9b36027f56cbeee3ebeeb953888f8e.jpg) +Input Image +Figure 1: Visualization of feature maps of teacher networks (RetinaNet-ResX101) and student networks (RetinaNet-Res50) with different KD paradigms. + +![](images/0f1ac6b509eb7a948d9e1dad720f961107c1e4098c9605be533391c8848f0151.jpg) +Feature of teacher + +![](images/a8e5b2815d34bff0f4d0a8538dc29e833d15108fa431957da5cad3ad9c563c63.jpg) +FitNet + +![](images/62441c15f3864316b7ba3c9744c673472da610a1c280fa5c92a8dad9e53acadd.jpg) +FGD + +![](images/b60be4c24b36845f929a341bb6704d967209689e0ae6fb4aafbf280ffe4a2e4b.jpg) +MKD + +model via a high-capacity teacher introduces an effective paradigm, which is widely known as Knowledge Distillation (KD) [16, 4]. For dense visual prediction tasks, feature-based distillation [17, 7, 11] is more beneficial for the student to mimic the teacher's intermediate features. Some elaborated feature-based distillation methods [29, 4, 40, 18] have established the state-of-the-art performance for many lightweight models such as ResNet-18 [15]. + +The core bottleneck of such feature-based KD is how to learn the complete knowledge from the teacher's output containing about 20K spatial coordinates (calculated on the COCO training set). According to our experiment, $72\%$ of them are simple enough and converge quickly to achieve $\sim 90\%$ similarity with the teacher's output. The remaining important knowledge is suppressed by this large number of simple samples, and it is difficult for the student to learn effectively. To further verify the existence of information redundancy in teacher features, we conduct experiments that, when $30\%$ of the features are randomly masked during training and testing on Retina-R101 (38.4 mAP), it still achieved similar performance (38.1 mAP). Previous works [34, 46] point out similar observations that each pixel contributes equally if using a common distillation loss (e.g. MSE), which will cause the network to easily learn a lot of similar information and is hard to identify important information. So they use attention [45, 40] and decouple the + +foreground and background feature [34, 46] to help alleviate this problem. But attention can still lead to the imbalance of information learning. + +In order to learn the complete information without being affected by the spatial redundancy in teacher features, we introduce the Mask Image Modeling (MIM) mechanism to effectively promote the learning of this information. To be more specific, we propose a new Masked Knowledge Distillation (MKD) framework to improve the knowledge learning of the student via the masked autoencoding paradigm. The core idea is that we mask random patches of the input image of the student while maintaining the whole input image for the teacher, and then recover the corresponding missing feature by forcing the student to imitate the output of the teacher. In this way, the student network is encouraged to predict the masked patches with corrupted input images and learn the relationship between the masked area and its surrounding regions, rather than simply imitating the output feature of the teacher at visible patches. We conduct some experiments trying to excavate the potential ability of the students. As shown in Fig. 1, according to the feature comparison in the red box, it can be observed that student network using MKD learns more complete knowledge from teacher than the direct feature-based method [1] and the attention-based method [40]. + +We introduce two crucial designs to alleviate some bottlenecks in this framework. First, due to the masked image input, directly applying the normal convolution in the convolutional neural networks (CNN) will confuse the latent representation in visible and invisible patches. Therefore, we adopt the masked convolution [10, 23] to keep the masked patches not affected by others in each convolution block. Second, multi-scale features are often used in fine-grained high-level visual tasks which have different masked sizes, leading to inconsistent feature reconstruction. We developed an adaptive decoder architecture for this problem to predict the teacher's feature in the corresponding masked area. More specifically, a spatial alignment module is first operated on the multi-scale features to align them to the same spatial resolution. A mask token is then replicated multiple times to replace the features in the masked area. The features in the visible patches and mask tokens are sent to an adaptive transformer decoder to reconstruct the teacher's feature. Finally, we conduct the spatial recovery module to convert the same spatial resolution to the original multi-scale resolution to perform feature-based distillation. + +In our method, by the mask autoencoding paradigm with asymmetric input for student and teacher, the student is forced to infer the teacher's features in the invisible patches by imitating the teacher's features in the visible patches. We observe that the mask tokens in the decoder try to absorb knowledge from their adjacent region to restore the features in the masked region. Completely restoring the masked fea + +![](images/94053f2caded8635b717900e1f8436c3fe8470fbab8920adc72b24e9b2a22953.jpg) +Figure 2: The average L2 distance between student's feature and teacher's feature calculated at the unmasked areas with RetinaNet-ResX101 distilling RetinaNet-Res50. + +tures drives it to fully learn the teacher's corresponding information in these adjacent areas. As shown in Fig. 2, the L2 distance value in adjacent regions of the mask can be lower with masked input. This verifies the claim that the student network can better learn the teacher's knowledge in our learning manner. MKD can be directly used in different architectures and various dense visual prediction tasks, e.g., object detection and semantic segmentation. The results show that MKD can improve considerably cooperated with conventional feature-based distillation. For instance, with MKD in RetinaNet, the mAP of student ResNet-18 is greatly improved to 37.5, $4.1\%$ higher than the baseline, and also outperforms the previous SOTA methods. To sum up, our contributions are as follows: + +- We propose a new paradigm for feature-based distillation named MKD, using mask autoencoding scheme to effectively learn the complete knowledge in the teacher network. MKD masks random patches of the input image and recovers the corresponding masked feature by forcing it to imitate the teacher's output. +- We introduce the masked convolution and adaptive decoder module in MKD to make it easy to cooperate with different architectures in fine-grained visual tasks, e.g., object detection and semantic segmentation. +- Extensive experiments on various models and tasks verify the effectiveness of our method. For different student architectures and tasks, MKD can further improve the performance of feature-based distillation and establish new state-of-the-art. + +# 2. Related Works + +# 2.1. Object Detection + +As a fundamental and challenging task in computer vision, object detection aims to detect the visual objects of a certain class in the images. Modern object detectors can be broadly divided into three paradigms: two- + +![](images/e72b0469a43ed8ae8380105c960dd74dd1732ec208415998e15297a9c14380de.jpg) +Figure 3: Illustration of the MKD. For clear visualization, we omit the original task losses, such as classification and localization loss. In this learning process, the parameter of the teacher is fixed. The mask token and decoder are not shared between different-scale features in FPN due to the semantic gap in different-scale features. + +![](images/0f7c45bab01ba00024ba3ecee519c31078749cc7c5df8de41862d717ee394340.jpg) + +stage [28, 14, 35], anchor-based one-stage [21, 32, 24], and anchor-free one-stage [43, 9]. While detectors with strong backbones have better accuracy, they are computationally expensive and difficult to deploy on mobile devices. One interesting direction of research is the compression of detection networks, including quantization [36, 19], pruning [12, 38], and the design of lightweight networks [31]. In addition, Knowledge Distillation (KD) [16, 46, 37], has become an important method for transferring knowledge from larger, better-performing networks without changing the structure of the network. + +# 2.2. Knowledge Distillation for Detection + +Knowledge distillation is a model compression and acceleration method that can transfer knowledge from the teacher model to the student model. The logit-based distillation methods [16, 46, 44] in classification are limited for the improvement of the fine-grained visual understanding tasks because the localization information from the teacher is crucial. Therefore, feature-based distillation over multiscale features has become the main method of distillation for detectors. Current feature distillation methods for detectors can be divided into the following four categories: (1) hint-based, (2) attention-based, (3) instance-based, and (4) masked-feature based. Hint-based methods [29, 1, 33, 42] take features from the intermediate layers as hints to guide the student model. However, such methods treat all regions equally and do not get satisfactory results. Instance-based methods aim to find the key instance regions for distillation by GT boxes or specifically designed modules, e.g. FGFI [34], GID [7], ICD [17]. Attention-based methods further improve the performance by using attention maps to + +locate discriminative areas, e.g. FKD [45], FGD [40]. Recent work MGD [41] first proposed to mask out the feature maps in the knowledge distillation branch and use a generator to restore the teacher feature. In our work, we mask random patches of the original images and adopt masked convolution into the backbone network to prevent information leakage. This new paradigm introduces masks throughout the backbone network, enhancing the corresponding knowledge learning in adjacent regions of the random mask. Experiments have shown that distillation benefits well from the masking scheme, especially for longer schedules. + +# 3. Approach + +# 3.1. Masked Knowledge Distillation + +We first elaborate on the overall pipeline of our masked knowledge distillation (MKD) by instantiating an example in object detection. Let $F^{S} \in \mathbb{R}^{C \times H \times W}$ and $F^{T} \in \mathbb{R}^{C \times H \times W}$ denote the output features of student's FPN and teacher's FPN, respectively. The standard feature-based distillation can be formulated as: + +$$ +\mathcal {L} _ {\text {f e a t}} = \frac {1}{2 N} \sum_ {i = 0} ^ {\mathcal {P}} \left(F _ {i} ^ {T} - \phi \left(F _ {i} ^ {S}\right)\right) ^ {2}, \tag {1} +$$ + +where $\mathcal{P}$ indicates the total number of features in FPN and $\mathrm{N} = \mathrm{C_iH_iW_i}$ . $C_i, H_i, W_i$ represent the channel number, height, and width for feature map $F_{i}^{*}$ . $\phi$ is a convolutional layer with kernel size $1\times 1$ to align the channel dimension between the $F^T$ and $F^{S}$ . + +As discussed above, to further enhance KD distillation dense visual predictions, we introduce the masked autoen + +coding scheme into KD learning. In this manner, the distillation of the features can be formulated as: + +$$ +\mathcal {L} _ {\text {f e a t}} = \frac {1}{2 N} \sum_ {i = 0} ^ {\mathcal {P}} \left(F _ {i} ^ {T} - f _ {\text {d e c}} \left(\phi \left(F _ {i} ^ {S}\right), \mathcal {T} _ {\text {m a s k}}\right)\right) ^ {2}, \tag {2} +$$ + +where $f_{dec}$ is the proposed adaptive decoder module with spatial alignment module, stacked transformer decoder layers, and spatial recovery module. $T_{mask}$ is the mask token. + +The overall architecture of MKD is shown in Fig. 3. Firstly, given an image with $H \times W$ , a binary mask map $\mathcal{M}$ with the element number $N = \frac{H}{s} \times \frac{W}{s}$ is randomly sampled with a given masking ratio. $s$ is the down-sampled factor of the mask map and we set it to 32 in our experiments. We progressively upsample the mask to align its resolution to the output of each convolutional stage in the student's backbone. Using the student as an encoder, the masked images are then sent to it and the masked residual blocks in each masked convolutional stage are conducted to leave the masked area unprocessed by the backbone in the forward process. Finally, the masked feature maps generated by FPN will be sent to an adaptive decoder module where a spatial alignment module (SAM) is introduced to operate on the multi-scale features, along with a decoder and spatial recovery module (SRM) that reconstructs the latent representations with mask tokens. This learning manner is supervised by forcing the student's output of the adaptive decoder to imitate the teacher's output. Even if we mask random patches of the input image, with the assistance of MKD, the student model can still infer the features of the invisible patches. + +# 3.1.1 Masking in the Image Space. + +Following ViT [8] and MAE [13], we first divide the input image into regular non-overlapping image patches, and then randomly generate a binary mask according to the given masking ratio. The masked area in the input image keeps unseen to the student model. We simply refer to this as "random masking". Notice that the random masking strategy follows a uniform distribution, which eliminates the potential center bias. The mask is illustrated in Fig. 3, which is a schematic gram, and the real masked image is shown in Fig. 1. Different from ViT, the convolutional neural network is designed with a pyramid scheme where different convolutional stages are set with different stride factors. This leads to multiple different spatial resolutions in the student's forward propagation. To make consistent with this, after generating a mask with resolution $\frac{H}{32} \times \frac{W}{32}$ for the late stage in the student, we progressively upsample the mask to larger resolutions in early convolutional stages as shown in Fig. 3. Introducing random masking to knowledge distillation can create a task that cannot be easily solved by directly performing the pixel-to-pixel spatial matching supervision. + +![](images/44507fda4160f07bd9321217b78f1c75f3186daed15c9449973a754a61149cc2.jpg) +Figure 4: Illustration of the adaptive decoder. The inputs are the corresponding mask and feature maps from the teacher's FPN and the student's FPN. + +# 3.1.2 Masked Encoder. + +In our MKD, the student backbone is used as the encoder to process the masked input image. To ensure that the network only operates on the visible patches and reconstructs only from the neighboring ones, previously masked auto-encoders such as MAE proposed to forward only the visible tokens into the encoder. However, this method cannot be used directly in convolutional networks since we need to preserve the spatial dimension of the image. Following ConvMAE [10], we adopt the masked convolution to solve this problem, which is commonly used in image inpainting [23] and sparse feature extraction [27] to process the incomplete input information. More specifically, masked convolutions are used in all blocks for each stage in the whole student so that the masked regions are not involved in the encoding process. The operation of masked convolution is shown in Fig. 3, where the input feature maps from the previous layer are masked firstly by performing the Hadamard product with the mask map. This can effectively avoid the confusing feature interaction between masked and visible regions. In this way, the decoder can only speculate based on the information of adjacent image blocks during reconstruction. We assume that this will help the encoder learn more expressive and content-rich features. + +# 3.1.3 Adaptive Decoder. + +The input to the adaptive decoder is the multi-scale masked feature maps of the student followed by a $1 \times 1$ convolu + +tion layer to align the channel number. The masked sizes are different in these multi-scale features, which leads to inconsistent feature reconstruction. To alleviate this, we introduce a simple spatial alignment module (SAM) to align them to the same spatial resolution ( $\frac{1}{32}$ of the input image size in our experiments). As shown in Fig. 4, this is implemented by convolutional layer with stride $p$ or upsampling the spatial resolution by a factor of $\frac{1}{p}$ (using nearest neighbor upsampling for simplicity), where scaling factor $p = H_i / \frac{H}{32} = W_i / \frac{W}{32}$ is the multiplier to the target size. And then, a specific mask token is initialized for each feature scale and then replicated multiple times to replace the features in the masked area. See Fig. 3. Each mask token is a learned vector and is not shared between different feature scales. Different from the fixed input size in the classification task, the input size of the image is flexible, and this requires the same flexible positional embedding generation. We conduct the position encoding in an absolute scale, e.g., $28 \times 28$ , and adaptively interpolate its resolution according to the input image size. We then add the positional embeddings to all tokens in each feature scale and send them to a series of transformer blocks to perform the feature reconstruction task. The final outputs of the transformer blocks are then restored to the original multi-scale resolutions via the spatial recovery module (SRM). In the SRM, we adopt a linear layer to change the channel numbers to $p^2 \times C_i^T$ ( $p$ is the same scaling factor used in SAM) and further reshape into the same size as $F_i^T$ . The output of SRM is forced to imitate the teacher's output and learns to reconstruct the missing feature. Note that the adaptive decoder is only used during training to perform the masked KD task. + +# 3.1.4 Distillation Target. + +Denote the output of SRM as $\hat{F}_i^S\in \mathbb{R}^{C_i^T\times H_i\times W_i}$ where $i$ indicates the feature index in FPN and $C_i^T,H_i,W_i$ indicate the channel number, height and width of the corresponding feature. The feature-based distillation loss can be formulated as follows: + +$$ +\mathcal {L} _ {\text {f e a t}} = \frac {1}{2 N} \sum_ {i = 0} ^ {\mathcal {P}} \left(F _ {i} ^ {T} - \hat {F} _ {i} ^ {S}\right) ^ {2}, \tag {3} +$$ + +where $\mathcal{P}$ indicates the total number of features in FPN and $\mathrm{N} = \mathrm{C_iH_iW_i}$ . $\hat{F}_i^S$ is the output of $f_{dec}(\phi (F_i^S),\mathcal{T}_{mask})$ in Eq (2). Following the state-of-the-art feature-based distillation method FGD [40], we introduce the global distillation loss $\mathcal{L}_{global}$ to assist the distillation learning, which can be formulated as: + +$$ +\mathcal {L} _ {\text {g l o b a l}} = \sum_ {i = 0} ^ {\mathcal {P}} \left(R \left(F _ {i} ^ {T}\right) - R \left(\hat {F} _ {i} ^ {S}\right)\right) ^ {2}, \tag {4} +$$ + +where $R$ denotes GCBlock in FGD. Note that before computing $\mathcal{L}_{feat}$ and $\mathcal{L}_{global}$ we have $F^S$ and $F^T$ pass a layer normalization operation as well before MSE loss. + +To summarize, the overall training loss of the proposed MKD includes (a) task loss $L_{task}$ , e.g., classification loss and regression loss in object detection; (b) feature-based distillation loss $L_{feat}$ and $L_{global}$ . It can be formulated as follows: + +$$ +\mathcal {L} _ {\text {t o t a l}} = \mathcal {L} _ {\text {t a s k}} + \lambda \mathcal {L} _ {\text {f e a t}} + \gamma \mathcal {L} _ {\text {g l o b a l}} \tag {5} +$$ + +where $\lambda$ and $\gamma$ are the weights to balance the distillation losses. The total distillation process is model-agnostic, so it works well with a variety of different structures. + +# 3.2. Discussion + +Feature-based distillation methods [29, 4, 41], such as hint-based [29, 1], attention-based [45, 40], and instance-based [34, 7, 17], have achieved superior performance improvement. They usually make the student imitate the teacher's output given fully visible image input and design different principles to extract the task-aware knowledge to guide the student's learning. But the redundant information in the teacher's feature hinders the complete knowledge learning of the student. + +As shown in Fig. 5, MGD [41] introduces the feature masking scheme to enhance the feature learning process by partially masking pixels in the feature maps from student's FPN. However, the information in the masked part has already been leaked during the forward process of the full image in the backbone. Thus, when minimizing KD loss, the effect of MGD is divided into two parts. First, since each adjacent pixel of the masked pixel already contains the information of the masked pixel, in the process of pushing student and teacher pair closer together, MGD extracts the masked feature from the leaked information in adjacent pixels and uses convolution to restore it. Second, the pixels around the masked pixels are pushed closer to the corresponding teacher. The effect of MGD is therefore dispersed, and even with the adaptive decoder proposed in our MKD, MGD is still not able to establish the connection between the masked and unmasked area as shown in Tab. 1. + +![](images/6183c0777567a4d79186ae60a63d3c36a7b931ab89c2f761a81961fe10d140cd.jpg) +Figure 5: Comparison of different distillation paradigms. + +Different from all these paradigms, MKD introduces a global decoder to learn the relationship between the masked + +
MethodmAPAP50AP75
original MGD [41]36.655.139.1
MGD + decoder in our MKD36.655.039.1
+ +area and its surroundings, shown in Fig. 5, promoting the learning of complete knowledge in teacher by KD. MKD masks information in the image space throughout the distillation process, which guarantees that the masked area is completely invisible to the student. Since there is no additional information leakage, MKD more strongly pushes the features of the teacher and the student closer during distillation. Moreover, we visualize the self-attention in the transformer decoder blocks in Fig. 6. To restore the feature of the unseen masked region, the student network is driven to fully learn corresponding knowledge from the adjacent areas. Thus, the feature imitation process is accordingly enhanced. To better understand this, we illustrate the L2 distance between the teacher's and student's features in the adjacent regions in Fig. 2. Our MKD can further enhance the student's learning and demonstrates superior improvement over the previous KD paradigms as shown in Tab. 3 and Tab. 2. + +![](images/86c5a2ca5a8d1b30af54e83ada69ee78e37137841a435f7f8f9809b77d0fc128.jpg) +Figure 6: The visualization of attention in decoder blocks. The square in red denotes the query. + +# 4. Experiments + +In order to evaluate the performance of our proposed method on object detection tasks, we first conduct experiments on the MS COCO dataset [22], which consists of 80 object categories and over $120\mathrm{k}$ images in total. We use $120\mathrm{k}$ images for training and $5\mathrm{k}$ images for testing, following the most common setting. We take mean average precision (mAP) as the evaluation metric of all the detectors. As for the semantic segmentation task, we evaluate our distillation method on the Cityscapes dataset [6] with $5\mathrm{k}$ high-quality images and evaluate the performance with mean Intersection-over-Union (mIoU). The shown results are the average value of three runs. + +Implementation Details. We train the student models with a batch size of 16 for 24 epochs (known as a $2 \times$ schedule). The initial learning rate is set by 0.01 for one-stage detectors and 0.02 for two-stage detectors. We reduce the learning rate by $0.1 \times$ at the 16th and 21st epochs. We adopt an early-stop mask strategy in the last 2 epochs, in which we set the masking ratio as 0.2 with a learning rate of 0.001 and without supervision from the teacher. This follows the co + +Table 1: Study on the decoder with Retina Res101-Res18. + +
MethodSchedulemAPAP50AP75
RetinaNet-ResX101(T)2x41.060.944.0
RetinaNet-Res50(S)2x37.456.739.6
FKD [45]2x39.6 (+2.2)58.842.1
FGD [40]2x40.4 (+3.0)59.943.3
MGD [41]2x40.7 (+3.3)59.442.8
MGD* [41]2x41.0 (+3.6)60.744.0
ours2x41.1 (+3.7)60.644.0
ours*2x41.5 (+4.1)61.144.3
RetinaNet-Res101(T)2x38.158.340.9
RetinaNet-MBV2(S)2x31.048.932.7
GID [7]2x33.5 (+2.5)51.935.5
FGD [40]2x35.6 (+4.6)53.838.1
MGD [41]2x35.5 (+4.5)
ours2x36.0 (+5.0)54.538.1
RetinaNet-Swin-s(T)1x39.760.142.2
RetinaNet-Swin-t(S)1x37.257.439.1
FGD [40]1x38.6 (+1.4)58.640.9
F=MGD [41]1x38.1 (+0.9)
ours1x39.3 (+2.1)59.541.6
+ +Table 2: Results on COCO dataset with large backbones and swim transformer backbones [26]. T and S denote the teacher and the student, respectively. + +sine schedule down to 0. In this way, the input distribution of the whole image is consistent with the test image. + +We use SGD as the optimizer and set the momentum and weight decay by 0.9 and 0.0001, respectively. We use the masking ratio of 0.1 by default and set the size of masked patches by 32. The number of adaptive decoder layers is 4. Transformer blocks in the decoder have 256 channels with a head number of 8, and the mlp ratio is set to be 8. The loss weight in Eq. 5 are set to be $\{\lambda = 3,\gamma = 3e - 6\}$ in single-stage detectors, $\{\lambda = 3,\gamma = 3e - 7\}$ in two-stage detectors, and $\{\lambda = 7,\gamma = 0\}$ in segmentation. All the experiments are conducted on 8 GPUs with mmdetection [2] and mmsegmentation [5] on PyTorch. + +# 4.1. Main Results + +Object detection. To verify the effectiveness of the MKD, we conduct experiments on popular detectors, i.e., RetinaNet [21], Faster R-CNN [28] and Reppoints [43] with various backbones, and the results are shown in Tab. 3 and Tab. 2. We can observe that the proposed MKD can consistently improve the student model by more than 2.5 mAP. For example, the Faster R-CNN with ResNet 50 can achieve $41.1\mathrm{mAP}$ when mimicking Faster R-CNN with ResNet 101 with MKD, which even surpasses the teacher. We further compare our method with the state-of-the-art for detection distillation under fair settings. Our MKD surpasses FGD [40] and MGD [41] on various student-teacher pairs. When distilling the RetinaNet-Res50 model with RetinaNet-ResX101 as the teacher, MKD transcends MGD with 0.4 on mAP and 1.2 on AP50. A similar trend can be observed when we choose smaller students like ResNet 18 as the backbone. + +
Method (The default training schedule is 2x)mAPAP50AP75APsAPmAPI
RetinaNet-Res101(Teacher network)38.958.041.521.042.852.4
RetinaNet-Res18(Student network)33.451.835.116.935.644.9
FKD [45]35.9 (+2.5)54.438.017.939.149.1
FGD [40]36.2 (+2.8)54.738.619.540.148.4
MGD [41]36.6 (+3.2)55.139.119.540.350.7
ours37.3 (+3.9)56.139.919.041.051.6
ours*(with the parameter inheriting scheme [17])37.5 (+4.1)56.039.919.441.551.2
RetinaNet-Res101(Teacher network)38.958.041.521.042.852.4
RetinaNet-Res50(Student network)37.456.739.620.040.749.7
GID [7]39.1 (+1.7)59.042.322.843.152.3
FGD [40]39.6 (+2.2)58.542.522.943.753.6
MGD [41]39.5 (+2.1)58.542.221.343.653.4
ours39.9 (+2.5)59.042.722.343.953.3
ours*(with the parameter inheriting scheme [17])40.2 (+2.8)59.343.022.344.454.0
FasterRCNN-Res101(Teacher network)39.860.143.322.543.652.8
FasterRCNN-Res50(Student network)38.459.042.021.542.150.3
FGFI [34]39.3 (+0.9)59.842.922.542.352.2
GID [7]40.2 (+1.8)60.743.822.744.053.2
FGD [40]40.4 (+2.0)60.744.322.844.553.5
MGD [41]40.1 (+1.7)60.243.622.944.253.3
ours41.0 (+2.6)61.544.723.545.553.4
ours*(with the parameter inheriting scheme [17])41.1 (+2.7)61.544.824.445.154.3
FCOS-Res101(Teacher network)40.860.044.024.244.352.4
FCOS-Res50(Student network)38.557.741.021.942.848.6
GID [7]42.0 (+3.5)60.445.525.645.854.2
FGD [40]42.1 (+3.6)--27.046.054.6
MGD [41]42.2(+3.7)60.945.326.646.354.7
ours42.5 (+4.0)61.246.126.646.854.6
ours*(with the parameter inheriting scheme [17])43.1 (+4.6)61.746.727.347.155.1
Reppoints-ResX101(Teacher network)44.265.547.826.248.458.5
Reppoints-Res50(Student network)38.659.641.622.542.250.4
FKD [45]40.6 (+2.0)61.743.823.444.653.0
FGD [40]41.3 (+2.7)--24.545.254.0
MGD [41]41.8 (+3.2)62.844.824.245.855.6
MGD [41]*(with the parameter inheriting scheme [17])42.3 (+3.7)63.345.424.446.255.9
ours42.2 (+3.6)63.045.624.346.455.7
ours*(with the parameter inheriting scheme [17])43.0 (+4.4)63.846.124.447.257.1
+ +Table 3: Object detection performance of our proposed MKD with various teacher-student pairs on the COCO dataset. + +Moreover, our method can benefit from a longer training schedule. For example, when training for 36 epochs, our MKD can further improve the performance of the student model over $4.0\mathrm{mAP}$ , which surpasses other methods by a larger margin than that for 12 epochs. This demonstrates that introducing a masked autoencoder into knowledge distillation can help the student avoid early saturation and benefit more from the distillation process. + +Semantic segmentation. Our MKD can be easily transferred to segmentation tasks such as semantic segmentation, and we conduct knowledge distillation experiments to show the generality of the proposed method. We choose PspNet-Res101 [47] as the teacher to distill PspNet-Res18 and DeepLabV3-Res18 [3]. As shown in Tab. 5, our method improves the PspNet-Res18 model with $4.85\mathrm{mIoU}$ , which greatly fills the gap between the student and the teacher. Also, MKD surpasses MGD and other methods by a signif + +icant margin, which verifies the effectiveness and generality of our method. + +Image classification. Since the core bottleneck is particularly prominent in fine-grained visual tasks that rely on spatial localization information, we mainly evaluate our methods on them. We also present the result of MKD on the classification task in Tab. 6, which further verifies its effectiveness. + +# 4.2. Ablation Study + +Masking ratio. We first examine the influence of different masking ratios on the performance shown in Fig. 7. Large masking ratios benefit more from longer training schedules. For example, a masking ratio of 0.1 achieves the best under a 1x schedule, while the best one changes to 0.3 under a 3x schedule. This is because a larger masking ratio introduces more difficulty to the distillation process and needs more + +
Patch SizemAPAP50AP75
Baseline37.456.739.6
1639.859.242.5
3239.959.342.5
6439.859.042.7
+ +(a) The patch size. + +
ResolutionmAPAP50AP75
w/o SAM, SRMOOM--
[H/16, W/16]38.958.041.6
[H/32, W/32]39.959.342.5
[H/64, W/64]39.759.142.2
+ +(b) The aligned resolution in SAM. + +
λmAPAP50AP75
039.658.842.5
139.959.242.8
339.959.342.5
539.759.042.6
+ +(c) The loss weights $\lambda$ + +
γmAPAP50AP75
039.759.042.6
1e-639.758.942.2
3e-639.959.342.5
5e-639.859.242.6
+ +(d) The loss weights $\gamma$ + +
DepthmAPAP50AP75
Baseline37.456.739.6
239.658.742.4
439.959.342.5
839.859.042.3
+ +(e) The depth of the adaptive decoder $N$ + +
Masked ConvolutionmAPAP50AP75
Baseline37.456.739.6
w/o39.658.842.5
w/39.959.342.5
+ +(f) The masked convolution. + +
Mask StrategymAPAP50AP75
Baseline37.456.739.6
Random39.959.342.5
Grid37.857.040.2
Block39.759.242.7
+ +(g) The masking strategy. +Table 4: Ablation study on the MKD design with RetinaNet-ResNet50 as student and RetinaNet-ResNeXt101 as a teacher under 1x training schedule. If not specified, the patch size is 32, $\lambda = 3$ , $\gamma = 3e - 6$ , the decoder has a depth of 4, and the mask is randomly sampled. + +
MethodinputsizemIoU
PspNet-Res101(T)512x102478.34
PspNet-Res18(S)512x51269.85
SKDS [25]512x51272.70
CWD [30]512x51273.53
MGD [41]512x51273.63
MGD* [41]512x51274.10
ours512x51273.99
ours*512x51274.70
PspNet-Res101(T)512x102478.34
DeepLabV3-Res18(S)512x51273.20
SKDS [25]512x51273.87
CWD [30]512x51275.93
MGD [41]512x51276.02
MGD* [41]512x51276.31
ours512x51276.14
ours*512x51276.63
+ +Table 5: Semantic segmentation result on Cityscape dataset. * means adopting an extra logits loss from CWD [30]. + +
MethodTop-1Top-5
ResNet-34(T)73.6291.59
ResNet-18(S)69.9089.43
FitNet [29]71.5090.27
SRRL [39]71.7390.60
MGD [41]71.8090.40
Ours72.0190.43
+ +Table 6: The performance of classification on ImageNet. + +optimization steps for the student to converge. + +Masked convolution. To keep the masked patches not affected by others in the convolution block, we introduce the masked convolution in our MKD, and the results of ablation on masked convolution are shown in Tab. 4f. Removing masked convolution from MKD will lead to a reduction of $0.3\mathrm{mAP}$ , which is still better than that of the baseline. This demonstrates that the masking operation indeed hinders the optimization of convolution blocks, and adopting masked convolution can effectively alleviate this issue. + +![](images/84731a4abba1ba636fe5472e2fd61320167eb230298fa464046634fda03591ef.jpg) +Figure 7: Illustration of the performance improvement of different masking ratios under different schedules. It appears that MKD (green) brings the greatest boost to the baseline (36.5mAP). + +Mask patch size. Here we examine how the masked patch size influences the distillation process. As shown in Tab. 4a, a patch size of 32 performs the best than other options. A smaller patch will lead to the confusing assignment of masked position in the last stage, which leads to inferior performance. On the contrary, using a larger patch size may distort the objects too much and make the edge vague. So we use a masked patch size of 32 by default in our work. + +SAM and SRM. We compare different aligned resolutions in SAM, and the results are shown in Tab. 4b. The training process appears to be out of memory(OOM) without spatial alignment operation, indicating that SAM and SRM are important in reducing computation and memory. We further found that setting the target resolution as $\frac{H}{32} \times \frac{W}{32}$ performs the best because it is the same size as the masked patches. + +Mask sampling strategies. Here we examine the influence of different masking strategies, e.g., masking randomly, masking in grids, and masking by block. Recent masked image modeling works show that random strategy works the best, and we observe a similar trend in our MKD. Note that to prevent the student network from learning the mask pat + +tern, it is necessary to use a global random mask. As shown in Tab. 4g, random masking surpasses other ways and is selected in other experiments in this paper. + +Adaptive decoder design. Adaptive decoder helps to reconstruct masked features from visible ones and is an important module in MKD. We choose different numbers of decoder layers and examine their effects on distillation performance. As shown in Tab. 4e, four layers perform the best. Due to the feature dimension and length of the sequence, we use four layers by default. Objects of different scales correspond to different feature levels of FPN, so we use unshared tokens for the reconstruction. While shared tokens cause a performance drop from $37.3\mathrm{mAP}$ to $37.0\mathrm{mAP}$ . + +Loss weight. In Eq. 5, we use two hyper-parameters $\lambda$ and $\gamma$ to balance the distillation loss, and we conduct ablation studies to investigate their sensitivities of them. From Tab. 4d and 4c, it can be seen that the performance of the student model is not sensitive to the choices of $\lambda$ and $\gamma$ , as the gap between the worst and the best is within $0.2\mathrm{mAP}$ . Note that $L_{feat}$ and $L_{global}$ are both distillation losses to calculate the similarity between the reconstructed output of the decoder $\hat{F}^S$ and teacher feature $F^T$ . The main difference is that $L_{feat}$ directly calculates MSE, and $L_{global}$ goes through a GCblock. Hence, the performance drop is small when $\lambda = 0$ or $\gamma = 0$ , as MKD already works when using either of the loss alone. + +# 5. Conclusion + +In this paper, we propose a new distillation paradigm Masked Knowledge Distillation (MKD), which introduces the masked autoencoding scheme to enhance the knowledge distillation process. MKD takes the masked image as input and predicts the whole feature map that is used to imitate the corresponding feature of the teacher network. By forcing the student network to learn the knowledge of the nearby region of the masked part to recover the full feature, the student can better transfer the corresponding information from the teacher, which helps to excavate the potential of the small student network. Extensive experimental results on various fine-grained visual tasks show its power in enhancing the improvement of knowledge distillation. + +# Acknowledgement + +This work was partly supported by the National Natural Science Foundation of China (Grant No. 61991451) and the Shenzhen Science and Technology Program (JCYJ20220818101001004). + +# References + +[1] Guobin Chen, Wongun Choi, Xiang Yu, Tony Han, and Manmohan Chandraker. Learning efficient object detection mod + +els with knowledge distillation. In NIPS, pages 742-751, 2017. 2, 3, 5 +[2] Kai Chen, Jiaqi Wang, Jiangmiao Pang, Yuhang Cao, Yu Xiong, Xiaoxiao Li, Shuyang Sun, Wansen Feng, Ziwei Liu, Jiarui Xu, et al. Mmdetection: Open mmlab detection toolbox and benchmark. arXiv preprint arXiv:1906.07155, 2019. 6 +[3] Liang-Chieh Chen, George Papandreou, Florian Schroff, and Hartwig Adam. Rethinking atrous convolution for semantic image segmentation. arXiv preprint arXiv:1706.05587, 2017. 7 +[4] Pengguang Chen, Shu Liu, Hengshuang Zhao, and Jiaya Jia. Distilling knowledge via knowledge review. In CVPR, pages 5008-5017, 2021. 1, 5 +[5] MMSegmentation Contributors. Mmsegmentation: Openmmlab semantic segmentation toolbox and benchmark. https://github.com/open-mmlab/mmsegmentation, 2020.6 +[6] Marius Cordts, Mohamed Omran, Sebastian Ramos, Timo Rehfeld, Markus Enzweiler, Rodrigo Benenson, Uwe Franke, Stefan Roth, and Bernt Schiele. The cityscapes dataset for semantic urban scene understanding. In CVPR, pages 3213-3223, 2016. 6 +[7] Xing Dai, Zeren Jiang, Zhao Wu, Yiping Bao, Zhicheng Wang, Si Liu, and Erjin Zhou. General instance distillation for object detection. In CVPR, pages 7842-7851, 2021. 1, 3, 5, 6, 7 +[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In ICLR, 2020. 4 +[9] Kaiwen Duan, Song Bai, Lingxi Xie, Honggang Qi, Qingming Huang, and Qi Tian. Centernet: Keypoint triplets for object detection. In ICCV, pages 6569-6578, 2019. 3 +[10] Peng Gao, Teli Ma, Hongsheng Li, Jifeng Dai, and Yu Qiao. Convmae: Masked convolution meets masked autoencoders. arXiv preprint arXiv:2205.03892, 2022. 2, 4 +[11] Kunyang Han, Yong Liu, Jun Hao Liew, Henghui Ding, Yunchao Wei, Jiajun Liu, Yitong Wang, Yansong Tang, Yujiu Yang, Jiashi Feng, et al. Global knowledge calibration for fast open-vocabulary segmentation. arXiv preprint arXiv:2303.09181, 2023. 1 +[12] Song Han, Jeff Pool, John Tran, and William Dally. Learning both weights and connections for efficient neural network. NIPS, 28, 2015. 3 +[13] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollar, and Ross Girshick. Masked autoencoders are scalable vision learners. In CVPR, pages 16000-16009, 2022. 4 +[14] Kaiming He, Georgia Gkioxari, Piotr Dólar, and Ross Girshick. Mask r-cnn. In ICCV, pages 2961-2969, 2017. 3 +[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778, 2016. 1 +[16] Geoffrey Hinton, Oriol Vinyals, and Jeff Dean. Distilling the knowledge in a neural network. Computer Science, 14(7):38-39, 2015. 1, 3 + +[17] Zijian Kang, Peizhen Zhang, Xiangyu Zhang, Jian Sun, and Nanning Zheng. Instance-conditional knowledge distillation for object detection. NIPS, 34:16468-16480, 2021. 1, 3, 5, 7 +[18] Quanquan Li, Shengying Jin, and Junjie Yan. Mimicking very efficient network for object detection. In CVPR, pages 6356-6364, 2017. 1 +[19] Rundong Li, Yan Wang, Feng Liang, Hongwei Qin, Junjie Yan, and Rui Fan. Fully quantized network for object detection. In CVPR, pages 2810-2819, 2019. 3 +[20] Tsung-Yi Lin, Piotr Dólar, Ross Girshick, Kaiming He, Bharath Hariharan, and Serge Belongie. Feature pyramid networks for object detection. In CVPR, pages 2117-2125, 2017. 1 +[21] Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dólar. Focal loss for dense object detection. In ICCV, pages 2980-2988, 2017. 3, 6 +[22] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dálár, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In ECCV, pages 740-755. Springer, 2014. 6 +[23] Guilin Liu, Fitsum A Reda, Kevin J Shih, Ting-Chun Wang, Andrew Tao, and Bryan Catanzaro. Image inpainting for irregular holes using partial convolutions. In ECCV, pages 85-100, 2018. 2, 4 +[24] Wei Liu, Dragomir Anguelov, Dumitru Erhan, Christian Szegedy, Scott Reed, Cheng-Yang Fu, and Alexander C Berg. Ssd: Single shot multibox detector. In ECCV, pages 21-37. Springer, 2016. 3 +[25] Yifan Liu, Ke Chen, Chris Liu, Zengchang Qin, Zhenbo Luo, and Jingdong Wang. Structured knowledge distillation for semantic segmentation. In CVPR, pages 2604-2613, 2019. 8 +[26] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In ICCV, pages 10012-10022, 2021. 6 +[27] Mengye Ren, Andrei Pokrovsky, Bin Yang, and Raquel Urtasun. Sbnet: Sparse blocks network for fast inference. In CVPR, pages 8711-8720, 2018. 4 +[28] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. NIPS, 28, 2015. 3, 6 +[29] Adriana Romero, Nicolas Ballas, Samira Ebrahimi Kahou, Antoine Chassang, Carlo Gatta, and Yoshua Bengio. Fitnets: Hints for thin deep nets. arXiv preprint arXiv:1412.6550, 2014. 1, 3, 5, 8 +[30] Changyong Shu, Yifan Liu, Jianfei Gao, Zheng Yan, and Chunhua Shen. Channel-wise knowledge distillation for dense prediction. In ICCV, pages 5311-5320, 2021. 8 +[31] Mingxing Tan, Ruoming Pang, and Quoc V Le. Efficientdet: Scalable and efficient object detection. In CVPR, pages 10781-10790, 2020. 3 +[32] Zhi Tian, Chunhua Shen, Hao Chen, and Tong He. Fcos: Fully convolutional one-stage object detection. In ICCV, pages 9627-9636, 2019. 3 + +[33] Jiahao Wang, Mingdeng Cao, Shuwei Shi, Baoyuan Wu, and Yujiu Yang. Attention probe: Vision transformer distillation in the wild. In ICASSP, pages 2220-2224. 3 +[34] Tao Wang, Li Yuan, Xiaopeng Zhang, and Jiashi Feng. Distilling object detectors with fine-grained feature imitation. In CVPR, pages 4933-4942, 2019. 1, 2, 3, 5, 7 +[35] Xinlong Wang, Rufeng Zhang, Tao Kong, Lei Li, and Chunhua Shen. Solov2: Dynamic and fast instance segmentation. NIPS, 33:17721-17732, 2020. 3 +[36] Yi Wei, Xinyu Pan, Hongwei Qin, Wanli Ouyang, and Junjie Yan. Quantization mimic: Towards very tiny cnn for object detection. In ECCV, pages 267-283, 2018. 3 +[37] Taiqiang Wu, Cheng Hou, Zhe Zhao, Shanshan Lao, Jiayi Li, Ngai Wong, and Yujiu Yang. Weight-inherited distillation for task-agnostic bert compression, 2023. 3 +[38] Xiang Xiang, Zhiyuan Wang, Shanshan Lao, and Baochang Zhang. Pruning multi-view stereo net for efficient 3d reconstruction. ISPRS Journal of Photogrammetry and Remote Sensing, 168:17-27, 2020. 3 +[39] Jing Yang, Brais Martinez, Adrian Bulat, Georgios Tzimiropoulos, et al. Knowledge distillation via softmax regression representation learning. ICLR, 2021. 8 +[40] Zhendong Yang, Zhe Li, Xiaohu Jiang, Yuan Gong, Zehuan Yuan, Danpei Zhao, and Chun Yuan. Focal and global knowledge distillation for detectors. In CVPR, pages 4643-4652, 2022. 1, 2, 3, 5, 6, 7 +[41] Zhendong Yang, Zhe Li, Mingqi Shao, Dachuan Shi, Zehuan Yuan, and Chun Yuan. Masked generative distillation. arXiv preprint arXiv:2205.01529, 2022. 3, 5, 6, 7, 8 +[42] Zhendong Yang, Zhe Li, Ailing Zeng, Zexian Li, Chun Yuan, and Yu Li. Vitkd: Practical guidelines for vit feature knowledge distillation. arXiv preprint arXiv:2209.02432, 2022. 3 +[43] Ze Yang, Shaohui Liu, Han Hu, Liwei Wang, and Stephen Lin. Repoints: Point set representation for object detection. In ICCV, pages 9657-9666, 2019. 3, 6 +[44] Zhendong Yang, Ailing Zeng, Zhe Li, Tianke Zhang, Chun Yuan, and Yu Li. From knowledge distillation to self-knowledge distillation: A unified approach with normalized loss and customized soft labels. arXiv preprint arXiv:2303.13005, 2023. 3 +[45] Linfeng Zhang and Kaisheng Ma. Improve object detection with feature-based knowledge distillation: Towards accurate and efficient detectors. In ICLR, 2020. 1, 3, 5, 6, 7 +[46] Borui Zhao, Quan Cui, Renjie Song, Yiyu Qiu, and Jiajun Liang. Decoupled knowledge distillation. In CVPR, pages 11953-11962, 2022. 1, 2, 3 +[47] Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, and Jiaya Jia. Pyramid scene parsing network. In CVPR, pages 2881-2890, 2017. 7 \ No newline at end of file diff --git a/2023/Masked Autoencoders Are Stronger Knowledge Distillers/images.zip b/2023/Masked Autoencoders Are Stronger Knowledge Distillers/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..bfb8bf3f5da85eba729634433ef8cb0087f6e8dc --- /dev/null +++ b/2023/Masked Autoencoders Are Stronger Knowledge Distillers/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:4cf9a9c338afdaf585041338075a6d1ba3a620a9290ddf53017897e98788119b +size 718883 diff --git a/2023/Masked Autoencoders Are Stronger Knowledge Distillers/layout.json b/2023/Masked Autoencoders Are Stronger Knowledge Distillers/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..975c5bbd046be7208a4b4bc66d46ec44d07e0822 --- /dev/null +++ b/2023/Masked Autoencoders Are Stronger Knowledge Distillers/layout.json @@ -0,0 +1,8423 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 119, + 103, + 474, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 119, + 103, + 474, + 121 + ], + "spans": [ + { + "bbox": [ + 119, + 103, + 474, + 121 + ], + "type": "text", + "content": "Masked Autoencoders Are Stronger Knowledge Distillers" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 119, + 141, + 475, + 184 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 119, + 141, + 475, + 184 + ], + "spans": [ + { + "bbox": [ + 119, + 141, + 475, + 184 + ], + "type": "text", + "content": "Shanshan Lao1* Guanglu Song2 Boxiao Liu2 Yu Liu2† Yujiu Yang1† \n1Tsinghua Shenzhen International Graduate School, Tsinghua University \n2Sensetime Research" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 109, + 187, + 484, + 213 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 109, + 187, + 484, + 213 + ], + "spans": [ + { + "bbox": [ + 109, + 187, + 484, + 213 + ], + "type": "text", + "content": "laoss21@mails.tsinghua.edu.cn, {songguanglu, liuboxiao}@sensetime.com \nliuyuisanai@gmail.com, yang.yujiu@sz.tsinghua.edu.cn" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 241, + 192, + 253 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 241, + 192, + 253 + ], + "spans": [ + { + "bbox": [ + 143, + 241, + 192, + 253 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 267, + 290, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 267, + 290, + 590 + ], + "spans": [ + { + "bbox": [ + 47, + 267, + 290, + 590 + ], + "type": "text", + "content": "Knowledge distillation (KD) has shown great success in improving student's performance by mimicking the intermediate output of the high-capacity teacher in fine-grained visual tasks, e.g. object detection. This paper proposes a technique called Masked Knowledge Distillation (MKD) that enhances this process using a masked autoencoding scheme. In MKD, random patches of the input image are masked, and the corresponding missing feature is recovered by forcing it to imitate the output of the teacher. MKD is based on two core designs. First, using the student as the encoder, we develop an adaptive decoder architecture, which includes a spatial alignment module that operates on the multi-scale features in the feature pyramid network (FPN) [20], a simple decoder, and a spatial recovery module that mimics the teacher's output from the latent representation and mask tokens. Second, we introduce the masked convolution in each convolution block to keep the masked patches unaffected by others. By coupling these two designs, we can further improve the completeness and effectiveness of teacher knowledge learning. We conduct extensive experiments on different architectures with object detection and semantic segmentation. The results show that all the students can achieve further improvements compared to the conventional KD. Notably, we establish the new state-of-the-art results by boosting RetinaNet ResNet-18, and ResNet-50 from 33.4 to 37.5 mAP, and 37.4 to 41.5 mAP, respectively." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 594, + 128, + 607 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 594, + 128, + 607 + ], + "spans": [ + { + "bbox": [ + 47, + 594, + 128, + 607 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 611, + 287, + 684 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 611, + 287, + 684 + ], + "spans": [ + { + "bbox": [ + 46, + 611, + 287, + 684 + ], + "type": "text", + "content": "As fundamental tasks in computer vision, high-level visual predictions such as object detection, instance segmentation, and semantic segmentation have been widely used in various practical applications. In real-world scenarios, improving the performance of the deployable models is crucial. Improving the performance of a lightweight student" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 308, + 240, + 355, + 336 + ], + "blocks": [ + { + "bbox": [ + 308, + 240, + 355, + 336 + ], + "lines": [ + { + "bbox": [ + 308, + 240, + 355, + 336 + ], + "spans": [ + { + "bbox": [ + 308, + 240, + 355, + 336 + ], + "type": "image", + "image_path": "88c66b86dd6bd0d387cdbabb322d17a69d9b36027f56cbeee3ebeeb953888f8e.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 317, + 336, + 346, + 343 + ], + "lines": [ + { + "bbox": [ + 317, + 336, + 346, + 343 + ], + "spans": [ + { + "bbox": [ + 317, + 336, + 346, + 343 + ], + "type": "text", + "content": "Input Image" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 305, + 351, + 546, + 389 + ], + "lines": [ + { + "bbox": [ + 305, + 351, + 546, + 389 + ], + "spans": [ + { + "bbox": [ + 305, + 351, + 546, + 389 + ], + "type": "text", + "content": "Figure 1: Visualization of feature maps of teacher networks (RetinaNet-ResX101) and student networks (RetinaNet-Res50) with different KD paradigms." + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 356, + 240, + 402, + 336 + ], + "blocks": [ + { + "bbox": [ + 356, + 240, + 402, + 336 + ], + "lines": [ + { + "bbox": [ + 356, + 240, + 402, + 336 + ], + "spans": [ + { + "bbox": [ + 356, + 240, + 402, + 336 + ], + "type": "image", + "image_path": "0f1ac6b509eb7a948d9e1dad720f961107c1e4098c9605be533391c8848f0151.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 358, + 336, + 400, + 342 + ], + "lines": [ + { + "bbox": [ + 358, + 336, + 400, + 342 + ], + "spans": [ + { + "bbox": [ + 358, + 336, + 400, + 342 + ], + "type": "text", + "content": "Feature of teacher" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 403, + 240, + 449, + 336 + ], + "blocks": [ + { + "bbox": [ + 403, + 240, + 449, + 336 + ], + "lines": [ + { + "bbox": [ + 403, + 240, + 449, + 336 + ], + "spans": [ + { + "bbox": [ + 403, + 240, + 449, + 336 + ], + "type": "image", + "image_path": "a8e5b2815d34bff0f4d0a8538dc29e833d15108fa431957da5cad3ad9c563c63.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 418, + 336, + 434, + 342 + ], + "lines": [ + { + "bbox": [ + 418, + 336, + 434, + 342 + ], + "spans": [ + { + "bbox": [ + 418, + 336, + 434, + 342 + ], + "type": "text", + "content": "FitNet" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 449, + 240, + 496, + 336 + ], + "blocks": [ + { + "bbox": [ + 449, + 240, + 496, + 336 + ], + "lines": [ + { + "bbox": [ + 449, + 240, + 496, + 336 + ], + "spans": [ + { + "bbox": [ + 449, + 240, + 496, + 336 + ], + "type": "image", + "image_path": "62441c15f3864316b7ba3c9744c673472da610a1c280fa5c92a8dad9e53acadd.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 466, + 336, + 480, + 342 + ], + "lines": [ + { + "bbox": [ + 466, + 336, + 480, + 342 + ], + "spans": [ + { + "bbox": [ + 466, + 336, + 480, + 342 + ], + "type": "text", + "content": "FGD" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 496, + 240, + 544, + 336 + ], + "blocks": [ + { + "bbox": [ + 496, + 240, + 544, + 336 + ], + "lines": [ + { + "bbox": [ + 496, + 240, + 544, + 336 + ], + "spans": [ + { + "bbox": [ + 496, + 240, + 544, + 336 + ], + "type": "image", + "image_path": "b60be4c24b36845f929a341bb6704d967209689e0ae6fb4aafbf280ffe4a2e4b.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 513, + 336, + 528, + 342 + ], + "lines": [ + { + "bbox": [ + 513, + 336, + 528, + 342 + ], + "spans": [ + { + "bbox": [ + 513, + 336, + 528, + 342 + ], + "type": "text", + "content": "MKD" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_caption" + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 398, + 546, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 398, + 546, + 495 + ], + "spans": [ + { + "bbox": [ + 304, + 398, + 546, + 495 + ], + "type": "text", + "content": "model via a high-capacity teacher introduces an effective paradigm, which is widely known as Knowledge Distillation (KD) [16, 4]. For dense visual prediction tasks, feature-based distillation [17, 7, 11] is more beneficial for the student to mimic the teacher's intermediate features. Some elaborated feature-based distillation methods [29, 4, 40, 18] have established the state-of-the-art performance for many lightweight models such as ResNet-18 [15]." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 498, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 498, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 498, + 547, + 714 + ], + "type": "text", + "content": "The core bottleneck of such feature-based KD is how to learn the complete knowledge from the teacher's output containing about 20K spatial coordinates (calculated on the COCO training set). According to our experiment, " + }, + { + "bbox": [ + 304, + 498, + 547, + 714 + ], + "type": "inline_equation", + "content": "72\\%" + }, + { + "bbox": [ + 304, + 498, + 547, + 714 + ], + "type": "text", + "content": " of them are simple enough and converge quickly to achieve " + }, + { + "bbox": [ + 304, + 498, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\sim 90\\%" + }, + { + "bbox": [ + 304, + 498, + 547, + 714 + ], + "type": "text", + "content": " similarity with the teacher's output. The remaining important knowledge is suppressed by this large number of simple samples, and it is difficult for the student to learn effectively. To further verify the existence of information redundancy in teacher features, we conduct experiments that, when " + }, + { + "bbox": [ + 304, + 498, + 547, + 714 + ], + "type": "inline_equation", + "content": "30\\%" + }, + { + "bbox": [ + 304, + 498, + 547, + 714 + ], + "type": "text", + "content": " of the features are randomly masked during training and testing on Retina-R101 (38.4 mAP), it still achieved similar performance (38.1 mAP). Previous works [34, 46] point out similar observations that each pixel contributes equally if using a common distillation loss (e.g. MSE), which will cause the network to easily learn a lot of similar information and is hard to identify important information. So they use attention [45, 40] and decouple the" + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 693, + 234, + 703 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 693, + 234, + 703 + ], + "spans": [ + { + "bbox": [ + 58, + 693, + 234, + 703 + ], + "type": "text", + "content": "*Work done during internship at SenseTime Research." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 703, + 138, + 712 + ], + "type": "text", + "content": "† Corresponding authors." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6384" + } + ] + } + ], + "index": 25 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 108 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 108 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 108 + ], + "type": "text", + "content": "foreground and background feature [34, 46] to help alleviate this problem. But attention can still lead to the imbalance of information learning." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 110, + 288, + 374 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 110, + 288, + 374 + ], + "spans": [ + { + "bbox": [ + 46, + 110, + 288, + 374 + ], + "type": "text", + "content": "In order to learn the complete information without being affected by the spatial redundancy in teacher features, we introduce the Mask Image Modeling (MIM) mechanism to effectively promote the learning of this information. To be more specific, we propose a new Masked Knowledge Distillation (MKD) framework to improve the knowledge learning of the student via the masked autoencoding paradigm. The core idea is that we mask random patches of the input image of the student while maintaining the whole input image for the teacher, and then recover the corresponding missing feature by forcing the student to imitate the output of the teacher. In this way, the student network is encouraged to predict the masked patches with corrupted input images and learn the relationship between the masked area and its surrounding regions, rather than simply imitating the output feature of the teacher at visible patches. We conduct some experiments trying to excavate the potential ability of the students. As shown in Fig. 1, according to the feature comparison in the red box, it can be observed that student network using MKD learns more complete knowledge from teacher than the direct feature-based method [1] and the attention-based method [40]." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 376, + 288, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 376, + 288, + 628 + ], + "spans": [ + { + "bbox": [ + 46, + 376, + 288, + 628 + ], + "type": "text", + "content": "We introduce two crucial designs to alleviate some bottlenecks in this framework. First, due to the masked image input, directly applying the normal convolution in the convolutional neural networks (CNN) will confuse the latent representation in visible and invisible patches. Therefore, we adopt the masked convolution [10, 23] to keep the masked patches not affected by others in each convolution block. Second, multi-scale features are often used in fine-grained high-level visual tasks which have different masked sizes, leading to inconsistent feature reconstruction. We developed an adaptive decoder architecture for this problem to predict the teacher's feature in the corresponding masked area. More specifically, a spatial alignment module is first operated on the multi-scale features to align them to the same spatial resolution. A mask token is then replicated multiple times to replace the features in the masked area. The features in the visible patches and mask tokens are sent to an adaptive transformer decoder to reconstruct the teacher's feature. Finally, we conduct the spatial recovery module to convert the same spatial resolution to the original multi-scale resolution to perform feature-based distillation." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 630, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 630, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 630, + 287, + 715 + ], + "type": "text", + "content": "In our method, by the mask autoencoding paradigm with asymmetric input for student and teacher, the student is forced to infer the teacher's features in the invisible patches by imitating the teacher's features in the visible patches. We observe that the mask tokens in the decoder try to absorb knowledge from their adjacent region to restore the features in the masked region. Completely restoring the masked fea" + } + ] + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 341, + 85, + 501, + 205 + ], + "blocks": [ + { + "bbox": [ + 341, + 85, + 501, + 205 + ], + "lines": [ + { + "bbox": [ + 341, + 85, + 501, + 205 + ], + "spans": [ + { + "bbox": [ + 341, + 85, + 501, + 205 + ], + "type": "image", + "image_path": "94053f2caded8635b717900e1f8436c3fe8470fbab8920adc72b24e9b2a22953.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 213, + 545, + 250 + ], + "lines": [ + { + "bbox": [ + 305, + 213, + 545, + 250 + ], + "spans": [ + { + "bbox": [ + 305, + 213, + 545, + 250 + ], + "type": "text", + "content": "Figure 2: The average L2 distance between student's feature and teacher's feature calculated at the unmasked areas with RetinaNet-ResX101 distilling RetinaNet-Res50." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 255, + 545, + 422 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 255, + 545, + 422 + ], + "spans": [ + { + "bbox": [ + 304, + 255, + 545, + 422 + ], + "type": "text", + "content": "tures drives it to fully learn the teacher's corresponding information in these adjacent areas. As shown in Fig. 2, the L2 distance value in adjacent regions of the mask can be lower with masked input. This verifies the claim that the student network can better learn the teacher's knowledge in our learning manner. MKD can be directly used in different architectures and various dense visual prediction tasks, e.g., object detection and semantic segmentation. The results show that MKD can improve considerably cooperated with conventional feature-based distillation. For instance, with MKD in RetinaNet, the mAP of student ResNet-18 is greatly improved to 37.5, " + }, + { + "bbox": [ + 304, + 255, + 545, + 422 + ], + "type": "inline_equation", + "content": "4.1\\%" + }, + { + "bbox": [ + 304, + 255, + 545, + 422 + ], + "type": "text", + "content": " higher than the baseline, and also outperforms the previous SOTA methods. To sum up, our contributions are as follows:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 425, + 545, + 618 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 317, + 425, + 545, + 497 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 425, + 545, + 497 + ], + "spans": [ + { + "bbox": [ + 317, + 425, + 545, + 497 + ], + "type": "text", + "content": "- We propose a new paradigm for feature-based distillation named MKD, using mask autoencoding scheme to effectively learn the complete knowledge in the teacher network. MKD masks random patches of the input image and recovers the corresponding masked feature by forcing it to imitate the teacher's output." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 503, + 545, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 503, + 545, + 552 + ], + "spans": [ + { + "bbox": [ + 317, + 503, + 545, + 552 + ], + "type": "text", + "content": "- We introduce the masked convolution and adaptive decoder module in MKD to make it easy to cooperate with different architectures in fine-grained visual tasks, e.g., object detection and semantic segmentation." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 317, + 559, + 545, + 618 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 559, + 545, + 618 + ], + "spans": [ + { + "bbox": [ + 317, + 559, + 545, + 618 + ], + "type": "text", + "content": "- Extensive experiments on various models and tasks verify the effectiveness of our method. For different student architectures and tasks, MKD can further improve the performance of feature-based distillation and establish new state-of-the-art." + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 628, + 398, + 639 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 628, + 398, + 639 + ], + "spans": [ + { + "bbox": [ + 306, + 628, + 398, + 639 + ], + "type": "text", + "content": "2. Related Works" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 647, + 408, + 660 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 647, + 408, + 660 + ], + "spans": [ + { + "bbox": [ + 306, + 647, + 408, + 660 + ], + "type": "text", + "content": "2.1. Object Detection" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 666, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 666, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 305, + 666, + 545, + 715 + ], + "type": "text", + "content": "As a fundamental and challenging task in computer vision, object detection aims to detect the visual objects of a certain class in the images. Modern object detectors can be broadly divided into three paradigms: two-" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "6385" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 60, + 70, + 345, + 277 + ], + "blocks": [ + { + "bbox": [ + 60, + 70, + 345, + 277 + ], + "lines": [ + { + "bbox": [ + 60, + 70, + 345, + 277 + ], + "spans": [ + { + "bbox": [ + 60, + 70, + 345, + 277 + ], + "type": "image", + "image_path": "e72b0469a43ed8ae8380105c960dd74dd1732ec208415998e15297a9c14380de.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 285, + 547, + 321 + ], + "lines": [ + { + "bbox": [ + 46, + 285, + 547, + 321 + ], + "spans": [ + { + "bbox": [ + 46, + 285, + 547, + 321 + ], + "type": "text", + "content": "Figure 3: Illustration of the MKD. For clear visualization, we omit the original task losses, such as classification and localization loss. In this learning process, the parameter of the teacher is fixed. The mask token and decoder are not shared between different-scale features in FPN due to the semantic gap in different-scale features." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 350, + 80, + 535, + 275 + ], + "blocks": [ + { + "bbox": [ + 350, + 80, + 535, + 275 + ], + "lines": [ + { + "bbox": [ + 350, + 80, + 535, + 275 + ], + "spans": [ + { + "bbox": [ + 350, + 80, + 535, + 275 + ], + "type": "image", + "image_path": "0f7c45bab01ba00024ba3ecee519c31078749cc7c5df8de41862d717ee394340.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 327, + 289, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 327, + 289, + 460 + ], + "spans": [ + { + "bbox": [ + 46, + 327, + 289, + 460 + ], + "type": "text", + "content": "stage [28, 14, 35], anchor-based one-stage [21, 32, 24], and anchor-free one-stage [43, 9]. While detectors with strong backbones have better accuracy, they are computationally expensive and difficult to deploy on mobile devices. One interesting direction of research is the compression of detection networks, including quantization [36, 19], pruning [12, 38], and the design of lightweight networks [31]. In addition, Knowledge Distillation (KD) [16, 46, 37], has become an important method for transferring knowledge from larger, better-performing networks without changing the structure of the network." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 468, + 241, + 480 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 468, + 241, + 480 + ], + "spans": [ + { + "bbox": [ + 47, + 468, + 241, + 480 + ], + "type": "text", + "content": "2.2. Knowledge Distillation for Detection" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 486, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 486, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 486, + 289, + 715 + ], + "type": "text", + "content": "Knowledge distillation is a model compression and acceleration method that can transfer knowledge from the teacher model to the student model. The logit-based distillation methods [16, 46, 44] in classification are limited for the improvement of the fine-grained visual understanding tasks because the localization information from the teacher is crucial. Therefore, feature-based distillation over multiscale features has become the main method of distillation for detectors. Current feature distillation methods for detectors can be divided into the following four categories: (1) hint-based, (2) attention-based, (3) instance-based, and (4) masked-feature based. Hint-based methods [29, 1, 33, 42] take features from the intermediate layers as hints to guide the student model. However, such methods treat all regions equally and do not get satisfactory results. Instance-based methods aim to find the key instance regions for distillation by GT boxes or specifically designed modules, e.g. FGFI [34], GID [7], ICD [17]. Attention-based methods further improve the performance by using attention maps to" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 327, + 547, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 327, + 547, + 460 + ], + "spans": [ + { + "bbox": [ + 304, + 327, + 547, + 460 + ], + "type": "text", + "content": "locate discriminative areas, e.g. FKD [45], FGD [40]. Recent work MGD [41] first proposed to mask out the feature maps in the knowledge distillation branch and use a generator to restore the teacher feature. In our work, we mask random patches of the original images and adopt masked convolution into the backbone network to prevent information leakage. This new paradigm introduces masks throughout the backbone network, enhancing the corresponding knowledge learning in adjacent regions of the random mask. Experiments have shown that distillation benefits well from the masking scheme, especially for longer schedules." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 471, + 373, + 484 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 471, + 373, + 484 + ], + "spans": [ + { + "bbox": [ + 306, + 471, + 373, + 484 + ], + "type": "text", + "content": "3. Approach" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 490, + 476, + 503 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 490, + 476, + 503 + ], + "spans": [ + { + "bbox": [ + 306, + 490, + 476, + 503 + ], + "type": "text", + "content": "3.1. Masked Knowledge Distillation" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 509, + 547, + 582 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 509, + 547, + 582 + ], + "spans": [ + { + "bbox": [ + 304, + 509, + 547, + 582 + ], + "type": "text", + "content": "We first elaborate on the overall pipeline of our masked knowledge distillation (MKD) by instantiating an example in object detection. Let " + }, + { + "bbox": [ + 304, + 509, + 547, + 582 + ], + "type": "inline_equation", + "content": "F^{S} \\in \\mathbb{R}^{C \\times H \\times W}" + }, + { + "bbox": [ + 304, + 509, + 547, + 582 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 509, + 547, + 582 + ], + "type": "inline_equation", + "content": "F^{T} \\in \\mathbb{R}^{C \\times H \\times W}" + }, + { + "bbox": [ + 304, + 509, + 547, + 582 + ], + "type": "text", + "content": " denote the output features of student's FPN and teacher's FPN, respectively. The standard feature-based distillation can be formulated as:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 345, + 588, + 545, + 622 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 345, + 588, + 545, + 622 + ], + "spans": [ + { + "bbox": [ + 345, + 588, + 545, + 622 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {f e a t}} = \\frac {1}{2 N} \\sum_ {i = 0} ^ {\\mathcal {P}} \\left(F _ {i} ^ {T} - \\phi \\left(F _ {i} ^ {S}\\right)\\right) ^ {2}, \\tag {1}", + "image_path": "2a4fff9611e03c85348943231e7a482156fc82d676c823f88573040387c23672.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "inline_equation", + "content": "\\mathcal{P}" + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "text", + "content": " indicates the total number of features in FPN and " + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "inline_equation", + "content": "\\mathrm{N} = \\mathrm{C_iH_iW_i}" + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "inline_equation", + "content": "C_i, H_i, W_i" + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "text", + "content": " represent the channel number, height, and width for feature map " + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "inline_equation", + "content": "F_{i}^{*}" + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "inline_equation", + "content": "\\phi" + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "text", + "content": " is a convolutional layer with kernel size " + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "inline_equation", + "content": "1\\times 1" + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "text", + "content": " to align the channel dimension between the " + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "inline_equation", + "content": "F^T" + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "inline_equation", + "content": "F^{S}" + }, + { + "bbox": [ + 304, + 629, + 545, + 688 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "content": "As discussed above, to further enhance KD distillation dense visual predictions, we introduce the masked autoen" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6386" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 95 + ], + "type": "text", + "content": "coding scheme into KD learning. In this manner, the distillation of the features can be formulated as:" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 59, + 102, + 287, + 134 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 102, + 287, + 134 + ], + "spans": [ + { + "bbox": [ + 59, + 102, + 287, + 134 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {f e a t}} = \\frac {1}{2 N} \\sum_ {i = 0} ^ {\\mathcal {P}} \\left(F _ {i} ^ {T} - f _ {\\text {d e c}} \\left(\\phi \\left(F _ {i} ^ {S}\\right), \\mathcal {T} _ {\\text {m a s k}}\\right)\\right) ^ {2}, \\tag {2}", + "image_path": "b8bfdc9c3ce4b84ef12035b84b2704a5113b27a0f0136ba1b326a50407b00642.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 142, + 287, + 178 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 142, + 287, + 178 + ], + "spans": [ + { + "bbox": [ + 46, + 142, + 287, + 178 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 142, + 287, + 178 + ], + "type": "inline_equation", + "content": "f_{dec}" + }, + { + "bbox": [ + 46, + 142, + 287, + 178 + ], + "type": "text", + "content": " is the proposed adaptive decoder module with spatial alignment module, stacked transformer decoder layers, and spatial recovery module. " + }, + { + "bbox": [ + 46, + 142, + 287, + 178 + ], + "type": "inline_equation", + "content": "T_{mask}" + }, + { + "bbox": [ + 46, + 142, + 287, + 178 + ], + "type": "text", + "content": " is the mask token." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 178, + 288, + 441 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 178, + 288, + 441 + ], + "spans": [ + { + "bbox": [ + 46, + 178, + 288, + 441 + ], + "type": "text", + "content": "The overall architecture of MKD is shown in Fig. 3. Firstly, given an image with " + }, + { + "bbox": [ + 46, + 178, + 288, + 441 + ], + "type": "inline_equation", + "content": "H \\times W" + }, + { + "bbox": [ + 46, + 178, + 288, + 441 + ], + "type": "text", + "content": ", a binary mask map " + }, + { + "bbox": [ + 46, + 178, + 288, + 441 + ], + "type": "inline_equation", + "content": "\\mathcal{M}" + }, + { + "bbox": [ + 46, + 178, + 288, + 441 + ], + "type": "text", + "content": " with the element number " + }, + { + "bbox": [ + 46, + 178, + 288, + 441 + ], + "type": "inline_equation", + "content": "N = \\frac{H}{s} \\times \\frac{W}{s}" + }, + { + "bbox": [ + 46, + 178, + 288, + 441 + ], + "type": "text", + "content": " is randomly sampled with a given masking ratio. " + }, + { + "bbox": [ + 46, + 178, + 288, + 441 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 46, + 178, + 288, + 441 + ], + "type": "text", + "content": " is the down-sampled factor of the mask map and we set it to 32 in our experiments. We progressively upsample the mask to align its resolution to the output of each convolutional stage in the student's backbone. Using the student as an encoder, the masked images are then sent to it and the masked residual blocks in each masked convolutional stage are conducted to leave the masked area unprocessed by the backbone in the forward process. Finally, the masked feature maps generated by FPN will be sent to an adaptive decoder module where a spatial alignment module (SAM) is introduced to operate on the multi-scale features, along with a decoder and spatial recovery module (SRM) that reconstructs the latent representations with mask tokens. This learning manner is supervised by forcing the student's output of the adaptive decoder to imitate the teacher's output. Even if we mask random patches of the input image, with the assistance of MKD, the student model can still infer the features of the invisible patches." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 455, + 203, + 467 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 455, + 203, + 467 + ], + "spans": [ + { + "bbox": [ + 47, + 455, + 203, + 467 + ], + "type": "text", + "content": "3.1.1 Masking in the Image Space." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 474, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 474, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 474, + 287, + 713 + ], + "type": "text", + "content": "Following ViT [8] and MAE [13], we first divide the input image into regular non-overlapping image patches, and then randomly generate a binary mask according to the given masking ratio. The masked area in the input image keeps unseen to the student model. We simply refer to this as \"random masking\". Notice that the random masking strategy follows a uniform distribution, which eliminates the potential center bias. The mask is illustrated in Fig. 3, which is a schematic gram, and the real masked image is shown in Fig. 1. Different from ViT, the convolutional neural network is designed with a pyramid scheme where different convolutional stages are set with different stride factors. This leads to multiple different spatial resolutions in the student's forward propagation. To make consistent with this, after generating a mask with resolution " + }, + { + "bbox": [ + 46, + 474, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\frac{H}{32} \\times \\frac{W}{32}" + }, + { + "bbox": [ + 46, + 474, + 287, + 713 + ], + "type": "text", + "content": " for the late stage in the student, we progressively upsample the mask to larger resolutions in early convolutional stages as shown in Fig. 3. Introducing random masking to knowledge distillation can create a task that cannot be easily solved by directly performing the pixel-to-pixel spatial matching supervision." + } + ] + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 325, + 70, + 529, + 300 + ], + "blocks": [ + { + "bbox": [ + 325, + 70, + 529, + 300 + ], + "lines": [ + { + "bbox": [ + 325, + 70, + 529, + 300 + ], + "spans": [ + { + "bbox": [ + 325, + 70, + 529, + 300 + ], + "type": "image", + "image_path": "44507fda4160f07bd9321217b78f1c75f3186daed15c9449973a754a61149cc2.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 308, + 546, + 344 + ], + "lines": [ + { + "bbox": [ + 305, + 308, + 546, + 344 + ], + "spans": [ + { + "bbox": [ + 305, + 308, + 546, + 344 + ], + "type": "text", + "content": "Figure 4: Illustration of the adaptive decoder. The inputs are the corresponding mask and feature maps from the teacher's FPN and the student's FPN." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 354, + 411, + 364 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 354, + 411, + 364 + ], + "spans": [ + { + "bbox": [ + 306, + 354, + 411, + 364 + ], + "type": "text", + "content": "3.1.2 Masked Encoder." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 374, + 546, + 649 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 374, + 546, + 649 + ], + "spans": [ + { + "bbox": [ + 304, + 374, + 546, + 649 + ], + "type": "text", + "content": "In our MKD, the student backbone is used as the encoder to process the masked input image. To ensure that the network only operates on the visible patches and reconstructs only from the neighboring ones, previously masked auto-encoders such as MAE proposed to forward only the visible tokens into the encoder. However, this method cannot be used directly in convolutional networks since we need to preserve the spatial dimension of the image. Following ConvMAE [10], we adopt the masked convolution to solve this problem, which is commonly used in image inpainting [23] and sparse feature extraction [27] to process the incomplete input information. More specifically, masked convolutions are used in all blocks for each stage in the whole student so that the masked regions are not involved in the encoding process. The operation of masked convolution is shown in Fig. 3, where the input feature maps from the previous layer are masked firstly by performing the Hadamard product with the mask map. This can effectively avoid the confusing feature interaction between masked and visible regions. In this way, the decoder can only speculate based on the information of adjacent image blocks during reconstruction. We assume that this will help the encoder learn more expressive and content-rich features." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 669, + 416, + 681 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 669, + 416, + 681 + ], + "spans": [ + { + "bbox": [ + 306, + 669, + 416, + 681 + ], + "type": "text", + "content": "3.1.3 Adaptive Decoder." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": "The input to the adaptive decoder is the multi-scale masked feature maps of the student followed by a " + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "inline_equation", + "content": "1 \\times 1" + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": " convolu" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6387" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "text", + "content": "tion layer to align the channel number. The masked sizes are different in these multi-scale features, which leads to inconsistent feature reconstruction. To alleviate this, we introduce a simple spatial alignment module (SAM) to align them to the same spatial resolution (" + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "inline_equation", + "content": "\\frac{1}{32}" + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "text", + "content": " of the input image size in our experiments). As shown in Fig. 4, this is implemented by convolutional layer with stride " + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "text", + "content": " or upsampling the spatial resolution by a factor of " + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "inline_equation", + "content": "\\frac{1}{p}" + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "text", + "content": " (using nearest neighbor upsampling for simplicity), where scaling factor " + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "inline_equation", + "content": "p = H_i / \\frac{H}{32} = W_i / \\frac{W}{32}" + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "text", + "content": " is the multiplier to the target size. And then, a specific mask token is initialized for each feature scale and then replicated multiple times to replace the features in the masked area. See Fig. 3. Each mask token is a learned vector and is not shared between different feature scales. Different from the fixed input size in the classification task, the input size of the image is flexible, and this requires the same flexible positional embedding generation. We conduct the position encoding in an absolute scale, e.g., " + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "inline_equation", + "content": "28 \\times 28" + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "text", + "content": ", and adaptively interpolate its resolution according to the input image size. We then add the positional embeddings to all tokens in each feature scale and send them to a series of transformer blocks to perform the feature reconstruction task. The final outputs of the transformer blocks are then restored to the original multi-scale resolutions via the spatial recovery module (SRM). In the SRM, we adopt a linear layer to change the channel numbers to " + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "inline_equation", + "content": "p^2 \\times C_i^T" + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "text", + "content": " (" + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "text", + "content": " is the same scaling factor used in SAM) and further reshape into the same size as " + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "inline_equation", + "content": "F_i^T" + }, + { + "bbox": [ + 47, + 72, + 289, + 443 + ], + "type": "text", + "content": ". The output of SRM is forced to imitate the teacher's output and learns to reconstruct the missing feature. Note that the adaptive decoder is only used during training to perform the masked KD task." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 445, + 162, + 457 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 445, + 162, + 457 + ], + "spans": [ + { + "bbox": [ + 47, + 445, + 162, + 457 + ], + "type": "text", + "content": "3.1.4 Distillation Target." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 463, + 287, + 523 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 463, + 287, + 523 + ], + "spans": [ + { + "bbox": [ + 47, + 463, + 287, + 523 + ], + "type": "text", + "content": "Denote the output of SRM as " + }, + { + "bbox": [ + 47, + 463, + 287, + 523 + ], + "type": "inline_equation", + "content": "\\hat{F}_i^S\\in \\mathbb{R}^{C_i^T\\times H_i\\times W_i}" + }, + { + "bbox": [ + 47, + 463, + 287, + 523 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 47, + 463, + 287, + 523 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 47, + 463, + 287, + 523 + ], + "type": "text", + "content": " indicates the feature index in FPN and " + }, + { + "bbox": [ + 47, + 463, + 287, + 523 + ], + "type": "inline_equation", + "content": "C_i^T,H_i,W_i" + }, + { + "bbox": [ + 47, + 463, + 287, + 523 + ], + "type": "text", + "content": " indicate the channel number, height and width of the corresponding feature. The feature-based distillation loss can be formulated as follows:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 93, + 528, + 287, + 561 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 93, + 528, + 287, + 561 + ], + "spans": [ + { + "bbox": [ + 93, + 528, + 287, + 561 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {f e a t}} = \\frac {1}{2 N} \\sum_ {i = 0} ^ {\\mathcal {P}} \\left(F _ {i} ^ {T} - \\hat {F} _ {i} ^ {S}\\right) ^ {2}, \\tag {3}", + "image_path": "c592044484c889358285adf018e10aa068ba83bf1e44c99ff18c0eb961a552ac.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "spans": [ + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "type": "inline_equation", + "content": "\\mathcal{P}" + }, + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "type": "text", + "content": " indicates the total number of features in FPN and " + }, + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "type": "inline_equation", + "content": "\\mathrm{N} = \\mathrm{C_iH_iW_i}" + }, + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "type": "inline_equation", + "content": "\\hat{F}_i^S" + }, + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "type": "text", + "content": " is the output of " + }, + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "type": "inline_equation", + "content": "f_{dec}(\\phi (F_i^S),\\mathcal{T}_{mask})" + }, + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "type": "text", + "content": " in Eq (2). Following the state-of-the-art feature-based distillation method FGD [40], we introduce the global distillation loss " + }, + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{global}" + }, + { + "bbox": [ + 47, + 565, + 287, + 637 + ], + "type": "text", + "content": " to assist the distillation learning, which can be formulated as:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 84, + 640, + 287, + 673 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 84, + 640, + 287, + 673 + ], + "spans": [ + { + "bbox": [ + 84, + 640, + 287, + 673 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {g l o b a l}} = \\sum_ {i = 0} ^ {\\mathcal {P}} \\left(R \\left(F _ {i} ^ {T}\\right) - R \\left(\\hat {F} _ {i} ^ {S}\\right)\\right) ^ {2}, \\tag {4}", + "image_path": "b85ee62363392368ca47f25154b92c85169364e6b584e7fcd8f46089a08e2b23.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "R" + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": " denotes GCBlock in FGD. Note that before computing " + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{feat}" + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{global}" + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": " we have " + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "F^S" + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "F^T" + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": " pass a layer normalization operation as well before MSE loss." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 72, + 546, + 131 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 546, + 131 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 546, + 131 + ], + "type": "text", + "content": "To summarize, the overall training loss of the proposed MKD includes (a) task loss " + }, + { + "bbox": [ + 304, + 72, + 546, + 131 + ], + "type": "inline_equation", + "content": "L_{task}" + }, + { + "bbox": [ + 304, + 72, + 546, + 131 + ], + "type": "text", + "content": ", e.g., classification loss and regression loss in object detection; (b) feature-based distillation loss " + }, + { + "bbox": [ + 304, + 72, + 546, + 131 + ], + "type": "inline_equation", + "content": "L_{feat}" + }, + { + "bbox": [ + 304, + 72, + 546, + 131 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 72, + 546, + 131 + ], + "type": "inline_equation", + "content": "L_{global}" + }, + { + "bbox": [ + 304, + 72, + 546, + 131 + ], + "type": "text", + "content": ". It can be formulated as follows:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 350, + 140, + 545, + 155 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 350, + 140, + 545, + 155 + ], + "spans": [ + { + "bbox": [ + 350, + 140, + 545, + 155 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\text {t a s k}} + \\lambda \\mathcal {L} _ {\\text {f e a t}} + \\gamma \\mathcal {L} _ {\\text {g l o b a l}} \\tag {5}", + "image_path": "b6c5c40788ae5cc4f88b37a538f032d76664a97497c609404d1e5e7be16c8b46.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 163, + 547, + 198 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 163, + 547, + 198 + ], + "spans": [ + { + "bbox": [ + 304, + 163, + 547, + 198 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 163, + 547, + 198 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 163, + 547, + 198 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 163, + 547, + 198 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 304, + 163, + 547, + 198 + ], + "type": "text", + "content": " are the weights to balance the distillation losses. The total distillation process is model-agnostic, so it works well with a variety of different structures." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 205, + 378, + 217 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 205, + 378, + 217 + ], + "spans": [ + { + "bbox": [ + 306, + 205, + 378, + 217 + ], + "type": "text", + "content": "3.2. Discussion" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 224, + 546, + 331 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 224, + 546, + 331 + ], + "spans": [ + { + "bbox": [ + 304, + 224, + 546, + 331 + ], + "type": "text", + "content": "Feature-based distillation methods [29, 4, 41], such as hint-based [29, 1], attention-based [45, 40], and instance-based [34, 7, 17], have achieved superior performance improvement. They usually make the student imitate the teacher's output given fully visible image input and design different principles to extract the task-aware knowledge to guide the student's learning. But the redundant information in the teacher's feature hinders the complete knowledge learning of the student." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 331, + 547, + 535 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 331, + 547, + 535 + ], + "spans": [ + { + "bbox": [ + 304, + 331, + 547, + 535 + ], + "type": "text", + "content": "As shown in Fig. 5, MGD [41] introduces the feature masking scheme to enhance the feature learning process by partially masking pixels in the feature maps from student's FPN. However, the information in the masked part has already been leaked during the forward process of the full image in the backbone. Thus, when minimizing KD loss, the effect of MGD is divided into two parts. First, since each adjacent pixel of the masked pixel already contains the information of the masked pixel, in the process of pushing student and teacher pair closer together, MGD extracts the masked feature from the leaked information in adjacent pixels and uses convolution to restore it. Second, the pixels around the masked pixels are pushed closer to the corresponding teacher. The effect of MGD is therefore dispersed, and even with the adaptive decoder proposed in our MKD, MGD is still not able to establish the connection between the masked and unmasked area as shown in Tab. 1." + } + ] + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 328, + 543, + 526, + 654 + ], + "blocks": [ + { + "bbox": [ + 328, + 543, + 526, + 654 + ], + "lines": [ + { + "bbox": [ + 328, + 543, + 526, + 654 + ], + "spans": [ + { + "bbox": [ + 328, + 543, + 526, + 654 + ], + "type": "image", + "image_path": "6183c0777567a4d79186ae60a63d3c36a7b931ab89c2f761a81961fe10d140cd.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 310, + 662, + 541, + 675 + ], + "lines": [ + { + "bbox": [ + 310, + 662, + 541, + 675 + ], + "spans": [ + { + "bbox": [ + 310, + 662, + 541, + 675 + ], + "type": "text", + "content": "Figure 5: Comparison of different distillation paradigms." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 689, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 547, + 713 + ], + "type": "text", + "content": "Different from all these paradigms, MKD introduces a global decoder to learn the relationship between the masked" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6388" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 69, + 70, + 268, + 112 + ], + "blocks": [ + { + "bbox": [ + 69, + 70, + 268, + 112 + ], + "lines": [ + { + "bbox": [ + 69, + 70, + 268, + 112 + ], + "spans": [ + { + "bbox": [ + 69, + 70, + 268, + 112 + ], + "type": "table", + "html": "
MethodmAPAP50AP75
original MGD [41]36.655.139.1
MGD + decoder in our MKD36.655.039.1
", + "image_path": "57c2cdb6b6020d652960368f828faff9ec01f045600cda57fb84a4c58cc6ae06.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 140, + 287, + 354 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 140, + 287, + 354 + ], + "spans": [ + { + "bbox": [ + 46, + 140, + 287, + 354 + ], + "type": "text", + "content": "area and its surroundings, shown in Fig. 5, promoting the learning of complete knowledge in teacher by KD. MKD masks information in the image space throughout the distillation process, which guarantees that the masked area is completely invisible to the student. Since there is no additional information leakage, MKD more strongly pushes the features of the teacher and the student closer during distillation. Moreover, we visualize the self-attention in the transformer decoder blocks in Fig. 6. To restore the feature of the unseen masked region, the student network is driven to fully learn corresponding knowledge from the adjacent areas. Thus, the feature imitation process is accordingly enhanced. To better understand this, we illustrate the L2 distance between the teacher's and student's features in the adjacent regions in Fig. 2. Our MKD can further enhance the student's learning and demonstrates superior improvement over the previous KD paradigms as shown in Tab. 3 and Tab. 2." + } + ] + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 72, + 356, + 263, + 399 + ], + "blocks": [ + { + "bbox": [ + 72, + 356, + 263, + 399 + ], + "lines": [ + { + "bbox": [ + 72, + 356, + 263, + 399 + ], + "spans": [ + { + "bbox": [ + 72, + 356, + 263, + 399 + ], + "type": "image", + "image_path": "86c5a2ca5a8d1b30af54e83ada69ee78e37137841a435f7f8f9809b77d0fc128.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 407, + 286, + 432 + ], + "lines": [ + { + "bbox": [ + 47, + 407, + 286, + 432 + ], + "spans": [ + { + "bbox": [ + 47, + 407, + 286, + 432 + ], + "type": "text", + "content": "Figure 6: The visualization of attention in decoder blocks. The square in red denotes the query." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 453, + 127, + 467 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 453, + 127, + 467 + ], + "spans": [ + { + "bbox": [ + 47, + 453, + 127, + 467 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 474, + 286, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 474, + 286, + 616 + ], + "spans": [ + { + "bbox": [ + 46, + 474, + 286, + 616 + ], + "type": "text", + "content": "In order to evaluate the performance of our proposed method on object detection tasks, we first conduct experiments on the MS COCO dataset [22], which consists of 80 object categories and over " + }, + { + "bbox": [ + 46, + 474, + 286, + 616 + ], + "type": "inline_equation", + "content": "120\\mathrm{k}" + }, + { + "bbox": [ + 46, + 474, + 286, + 616 + ], + "type": "text", + "content": " images in total. We use " + }, + { + "bbox": [ + 46, + 474, + 286, + 616 + ], + "type": "inline_equation", + "content": "120\\mathrm{k}" + }, + { + "bbox": [ + 46, + 474, + 286, + 616 + ], + "type": "text", + "content": " images for training and " + }, + { + "bbox": [ + 46, + 474, + 286, + 616 + ], + "type": "inline_equation", + "content": "5\\mathrm{k}" + }, + { + "bbox": [ + 46, + 474, + 286, + 616 + ], + "type": "text", + "content": " images for testing, following the most common setting. We take mean average precision (mAP) as the evaluation metric of all the detectors. As for the semantic segmentation task, we evaluate our distillation method on the Cityscapes dataset [6] with " + }, + { + "bbox": [ + 46, + 474, + 286, + 616 + ], + "type": "inline_equation", + "content": "5\\mathrm{k}" + }, + { + "bbox": [ + 46, + 474, + 286, + 616 + ], + "type": "text", + "content": " high-quality images and evaluate the performance with mean Intersection-over-Union (mIoU). The shown results are the average value of three runs." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 617, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 286, + 713 + ], + "type": "text", + "content": "Implementation Details. We train the student models with a batch size of 16 for 24 epochs (known as a " + }, + { + "bbox": [ + 46, + 617, + 286, + 713 + ], + "type": "inline_equation", + "content": "2 \\times" + }, + { + "bbox": [ + 46, + 617, + 286, + 713 + ], + "type": "text", + "content": " schedule). The initial learning rate is set by 0.01 for one-stage detectors and 0.02 for two-stage detectors. We reduce the learning rate by " + }, + { + "bbox": [ + 46, + 617, + 286, + 713 + ], + "type": "inline_equation", + "content": "0.1 \\times" + }, + { + "bbox": [ + 46, + 617, + 286, + 713 + ], + "type": "text", + "content": " at the 16th and 21st epochs. We adopt an early-stop mask strategy in the last 2 epochs, in which we set the masking ratio as 0.2 with a learning rate of 0.001 and without supervision from the teacher. This follows the co" + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 309, + 69, + 547, + 275 + ], + "blocks": [ + { + "bbox": [ + 48, + 121, + 284, + 133 + ], + "lines": [ + { + "bbox": [ + 48, + 121, + 284, + 133 + ], + "spans": [ + { + "bbox": [ + 48, + 121, + 284, + 133 + ], + "type": "text", + "content": "Table 1: Study on the decoder with Retina Res101-Res18." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 309, + 69, + 547, + 275 + ], + "lines": [ + { + "bbox": [ + 309, + 69, + 547, + 275 + ], + "spans": [ + { + "bbox": [ + 309, + 69, + 547, + 275 + ], + "type": "table", + "html": "
MethodSchedulemAPAP50AP75
RetinaNet-ResX101(T)2x41.060.944.0
RetinaNet-Res50(S)2x37.456.739.6
FKD [45]2x39.6 (+2.2)58.842.1
FGD [40]2x40.4 (+3.0)59.943.3
MGD [41]2x40.7 (+3.3)59.442.8
MGD* [41]2x41.0 (+3.6)60.744.0
ours2x41.1 (+3.7)60.644.0
ours*2x41.5 (+4.1)61.144.3
RetinaNet-Res101(T)2x38.158.340.9
RetinaNet-MBV2(S)2x31.048.932.7
GID [7]2x33.5 (+2.5)51.935.5
FGD [40]2x35.6 (+4.6)53.838.1
MGD [41]2x35.5 (+4.5)
ours2x36.0 (+5.0)54.538.1
RetinaNet-Swin-s(T)1x39.760.142.2
RetinaNet-Swin-t(S)1x37.257.439.1
FGD [40]1x38.6 (+1.4)58.640.9
F=MGD [41]1x38.1 (+0.9)
ours1x39.3 (+2.1)59.541.6
", + "image_path": "be762333d18997376b458bc6517bf3e1cfef102b60342fc253fad1ce2fa4816e.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 283, + 545, + 319 + ], + "lines": [ + { + "bbox": [ + 305, + 283, + 545, + 319 + ], + "spans": [ + { + "bbox": [ + 305, + 283, + 545, + 319 + ], + "type": "text", + "content": "Table 2: Results on COCO dataset with large backbones and swim transformer backbones [26]. T and S denote the teacher and the student, respectively." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 305, + 327, + 545, + 351 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 327, + 545, + 351 + ], + "spans": [ + { + "bbox": [ + 305, + 327, + 545, + 351 + ], + "type": "text", + "content": "sine schedule down to 0. In this way, the input distribution of the whole image is consistent with the test image." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 351, + 545, + 483 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 351, + 545, + 483 + ], + "spans": [ + { + "bbox": [ + 304, + 351, + 545, + 483 + ], + "type": "text", + "content": "We use SGD as the optimizer and set the momentum and weight decay by 0.9 and 0.0001, respectively. We use the masking ratio of 0.1 by default and set the size of masked patches by 32. The number of adaptive decoder layers is 4. Transformer blocks in the decoder have 256 channels with a head number of 8, and the mlp ratio is set to be 8. The loss weight in Eq. 5 are set to be " + }, + { + "bbox": [ + 304, + 351, + 545, + 483 + ], + "type": "inline_equation", + "content": "\\{\\lambda = 3,\\gamma = 3e - 6\\}" + }, + { + "bbox": [ + 304, + 351, + 545, + 483 + ], + "type": "text", + "content": " in single-stage detectors, " + }, + { + "bbox": [ + 304, + 351, + 545, + 483 + ], + "type": "inline_equation", + "content": "\\{\\lambda = 3,\\gamma = 3e - 7\\}" + }, + { + "bbox": [ + 304, + 351, + 545, + 483 + ], + "type": "text", + "content": " in two-stage detectors, and " + }, + { + "bbox": [ + 304, + 351, + 545, + 483 + ], + "type": "inline_equation", + "content": "\\{\\lambda = 7,\\gamma = 0\\}" + }, + { + "bbox": [ + 304, + 351, + 545, + 483 + ], + "type": "text", + "content": " in segmentation. All the experiments are conducted on 8 GPUs with mmdetection [2] and mmsegmentation [5] on PyTorch." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 491, + 390, + 502 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 491, + 390, + 502 + ], + "spans": [ + { + "bbox": [ + 306, + 491, + 390, + 502 + ], + "type": "text", + "content": "4.1. Main Results" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 510, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 510, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 545, + 712 + ], + "type": "text", + "content": "Object detection. To verify the effectiveness of the MKD, we conduct experiments on popular detectors, i.e., RetinaNet [21], Faster R-CNN [28] and Reppoints [43] with various backbones, and the results are shown in Tab. 3 and Tab. 2. We can observe that the proposed MKD can consistently improve the student model by more than 2.5 mAP. For example, the Faster R-CNN with ResNet 50 can achieve " + }, + { + "bbox": [ + 304, + 510, + 545, + 712 + ], + "type": "inline_equation", + "content": "41.1\\mathrm{mAP}" + }, + { + "bbox": [ + 304, + 510, + 545, + 712 + ], + "type": "text", + "content": " when mimicking Faster R-CNN with ResNet 101 with MKD, which even surpasses the teacher. We further compare our method with the state-of-the-art for detection distillation under fair settings. Our MKD surpasses FGD [40] and MGD [41] on various student-teacher pairs. When distilling the RetinaNet-Res50 model with RetinaNet-ResX101 as the teacher, MKD transcends MGD with 0.4 on mAP and 1.2 on AP50. A similar trend can be observed when we choose smaller students like ResNet 18 as the backbone." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6389" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 70, + 69, + 526, + 462 + ], + "blocks": [ + { + "bbox": [ + 70, + 69, + 526, + 462 + ], + "lines": [ + { + "bbox": [ + 70, + 69, + 526, + 462 + ], + "spans": [ + { + "bbox": [ + 70, + 69, + 526, + 462 + ], + "type": "table", + "html": "
Method (The default training schedule is 2x)mAPAP50AP75APsAPmAPI
RetinaNet-Res101(Teacher network)38.958.041.521.042.852.4
RetinaNet-Res18(Student network)33.451.835.116.935.644.9
FKD [45]35.9 (+2.5)54.438.017.939.149.1
FGD [40]36.2 (+2.8)54.738.619.540.148.4
MGD [41]36.6 (+3.2)55.139.119.540.350.7
ours37.3 (+3.9)56.139.919.041.051.6
ours*(with the parameter inheriting scheme [17])37.5 (+4.1)56.039.919.441.551.2
RetinaNet-Res101(Teacher network)38.958.041.521.042.852.4
RetinaNet-Res50(Student network)37.456.739.620.040.749.7
GID [7]39.1 (+1.7)59.042.322.843.152.3
FGD [40]39.6 (+2.2)58.542.522.943.753.6
MGD [41]39.5 (+2.1)58.542.221.343.653.4
ours39.9 (+2.5)59.042.722.343.953.3
ours*(with the parameter inheriting scheme [17])40.2 (+2.8)59.343.022.344.454.0
FasterRCNN-Res101(Teacher network)39.860.143.322.543.652.8
FasterRCNN-Res50(Student network)38.459.042.021.542.150.3
FGFI [34]39.3 (+0.9)59.842.922.542.352.2
GID [7]40.2 (+1.8)60.743.822.744.053.2
FGD [40]40.4 (+2.0)60.744.322.844.553.5
MGD [41]40.1 (+1.7)60.243.622.944.253.3
ours41.0 (+2.6)61.544.723.545.553.4
ours*(with the parameter inheriting scheme [17])41.1 (+2.7)61.544.824.445.154.3
FCOS-Res101(Teacher network)40.860.044.024.244.352.4
FCOS-Res50(Student network)38.557.741.021.942.848.6
GID [7]42.0 (+3.5)60.445.525.645.854.2
FGD [40]42.1 (+3.6)--27.046.054.6
MGD [41]42.2(+3.7)60.945.326.646.354.7
ours42.5 (+4.0)61.246.126.646.854.6
ours*(with the parameter inheriting scheme [17])43.1 (+4.6)61.746.727.347.155.1
Reppoints-ResX101(Teacher network)44.265.547.826.248.458.5
Reppoints-Res50(Student network)38.659.641.622.542.250.4
FKD [45]40.6 (+2.0)61.743.823.444.653.0
FGD [40]41.3 (+2.7)--24.545.254.0
MGD [41]41.8 (+3.2)62.844.824.245.855.6
MGD [41]*(with the parameter inheriting scheme [17])42.3 (+3.7)63.345.424.446.255.9
ours42.2 (+3.6)63.045.624.346.455.7
ours*(with the parameter inheriting scheme [17])43.0 (+4.4)63.846.124.447.257.1
", + "image_path": "6babc2353137660ba341a8052db2845c87622df466c92074e1ae6047a264a665.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 58, + 469, + 533, + 482 + ], + "lines": [ + { + "bbox": [ + 58, + 469, + 533, + 482 + ], + "spans": [ + { + "bbox": [ + 58, + 469, + 533, + 482 + ], + "type": "text", + "content": "Table 3: Object detection performance of our proposed MKD with various teacher-student pairs on the COCO dataset." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 502, + 288, + 598 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 502, + 288, + 598 + ], + "spans": [ + { + "bbox": [ + 46, + 502, + 288, + 598 + ], + "type": "text", + "content": "Moreover, our method can benefit from a longer training schedule. For example, when training for 36 epochs, our MKD can further improve the performance of the student model over " + }, + { + "bbox": [ + 46, + 502, + 288, + 598 + ], + "type": "inline_equation", + "content": "4.0\\mathrm{mAP}" + }, + { + "bbox": [ + 46, + 502, + 288, + 598 + ], + "type": "text", + "content": ", which surpasses other methods by a larger margin than that for 12 epochs. This demonstrates that introducing a masked autoencoder into knowledge distillation can help the student avoid early saturation and benefit more from the distillation process." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "content": "Semantic segmentation. Our MKD can be easily transferred to segmentation tasks such as semantic segmentation, and we conduct knowledge distillation experiments to show the generality of the proposed method. We choose PspNet-Res101 [47] as the teacher to distill PspNet-Res18 and DeepLabV3-Res18 [3]. As shown in Tab. 5, our method improves the PspNet-Res18 model with " + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "inline_equation", + "content": "4.85\\mathrm{mIoU}" + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "content": ", which greatly fills the gap between the student and the teacher. Also, MKD surpasses MGD and other methods by a signif" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 304, + 502, + 545, + 525 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 502, + 545, + 525 + ], + "spans": [ + { + "bbox": [ + 304, + 502, + 545, + 525 + ], + "type": "text", + "content": "icant margin, which verifies the effectiveness and generality of our method." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 528, + 545, + 598 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 528, + 545, + 598 + ], + "spans": [ + { + "bbox": [ + 304, + 528, + 545, + 598 + ], + "type": "text", + "content": "Image classification. Since the core bottleneck is particularly prominent in fine-grained visual tasks that rely on spatial localization information, we mainly evaluate our methods on them. We also present the result of MKD on the classification task in Tab. 6, which further verifies its effectiveness." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 609, + 400, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 609, + 400, + 624 + ], + "spans": [ + { + "bbox": [ + 305, + 609, + 400, + 624 + ], + "type": "text", + "content": "4.2. Ablation Study" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "text", + "content": "Masking ratio. We first examine the influence of different masking ratios on the performance shown in Fig. 7. Large masking ratios benefit more from longer training schedules. For example, a masking ratio of 0.1 achieves the best under a 1x schedule, while the best one changes to 0.3 under a 3x schedule. This is because a larger masking ratio introduces more difficulty to the distillation process and needs more" + } + ] + } + ], + "index": 7 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6390" + } + ] + } + ], + "index": 8 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 63, + 80, + 177, + 134 + ], + "blocks": [ + { + "bbox": [ + 63, + 80, + 177, + 134 + ], + "lines": [ + { + "bbox": [ + 63, + 80, + 177, + 134 + ], + "spans": [ + { + "bbox": [ + 63, + 80, + 177, + 134 + ], + "type": "table", + "html": "
Patch SizemAPAP50AP75
Baseline37.456.739.6
1639.859.242.5
3239.959.342.5
6439.859.042.7
", + "image_path": "bb32b0653227e6bb7a68244adb51e4bd87681786bec9401e105ba4869ded1945.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 191, + 80, + 326, + 135 + ], + "blocks": [ + { + "bbox": [ + 86, + 137, + 148, + 146 + ], + "lines": [ + { + "bbox": [ + 86, + 137, + 148, + 146 + ], + "spans": [ + { + "bbox": [ + 86, + 137, + 148, + 146 + ], + "type": "text", + "content": "(a) The patch size." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 191, + 80, + 326, + 135 + ], + "lines": [ + { + "bbox": [ + 191, + 80, + 326, + 135 + ], + "spans": [ + { + "bbox": [ + 191, + 80, + 326, + 135 + ], + "type": "table", + "html": "
ResolutionmAPAP50AP75
w/o SAM, SRMOOM--
[H/16, W/16]38.958.041.6
[H/32, W/32]39.959.342.5
[H/64, W/64]39.759.142.2
", + "image_path": "8a257637608b45d626d432abb3f68745f8a93bbf4ab8a31b1314ac684bcac116.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 331, + 80, + 424, + 135 + ], + "blocks": [ + { + "bbox": [ + 195, + 137, + 312, + 147 + ], + "lines": [ + { + "bbox": [ + 195, + 137, + 312, + 147 + ], + "spans": [ + { + "bbox": [ + 195, + 137, + 312, + 147 + ], + "type": "text", + "content": "(b) The aligned resolution in SAM." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 331, + 80, + 424, + 135 + ], + "lines": [ + { + "bbox": [ + 331, + 80, + 424, + 135 + ], + "spans": [ + { + "bbox": [ + 331, + 80, + 424, + 135 + ], + "type": "table", + "html": "
λmAPAP50AP75
039.658.842.5
139.959.242.8
339.959.342.5
539.759.042.6
", + "image_path": "2f231e18350270c89238ce5dc28bc41b2d01d457b826ec19d588eaaa7feb926f.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 440, + 80, + 533, + 134 + ], + "blocks": [ + { + "bbox": [ + 336, + 137, + 413, + 146 + ], + "lines": [ + { + "bbox": [ + 336, + 137, + 413, + 146 + ], + "spans": [ + { + "bbox": [ + 336, + 137, + 413, + 146 + ], + "type": "text", + "content": "(c) The loss weights " + }, + { + "bbox": [ + 336, + 137, + 413, + 146 + ], + "type": "inline_equation", + "content": "\\lambda" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 440, + 80, + 533, + 134 + ], + "lines": [ + { + "bbox": [ + 440, + 80, + 533, + 134 + ], + "spans": [ + { + "bbox": [ + 440, + 80, + 533, + 134 + ], + "type": "table", + "html": "
γmAPAP50AP75
039.759.042.6
1e-639.758.942.2
3e-639.959.342.5
5e-639.859.242.6
", + "image_path": "11a2a72ea076fd4a4e23124cd62132f9af948191994fc47e7dd644542b6b48ec.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 65, + 157, + 193, + 211 + ], + "blocks": [ + { + "bbox": [ + 446, + 137, + 523, + 147 + ], + "lines": [ + { + "bbox": [ + 446, + 137, + 523, + 147 + ], + "spans": [ + { + "bbox": [ + 446, + 137, + 523, + 147 + ], + "type": "text", + "content": "(d) The loss weights " + }, + { + "bbox": [ + 446, + 137, + 523, + 147 + ], + "type": "inline_equation", + "content": "\\gamma" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 65, + 157, + 193, + 211 + ], + "lines": [ + { + "bbox": [ + 65, + 157, + 193, + 211 + ], + "spans": [ + { + "bbox": [ + 65, + 157, + 193, + 211 + ], + "type": "table", + "html": "
DepthmAPAP50AP75
Baseline37.456.739.6
239.658.742.4
439.959.342.5
839.859.042.3
", + "image_path": "4d3446f4df478f3e86ad2040282ab17d0b26db7990e622329f91e682c9c87dde.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 217, + 157, + 358, + 211 + ], + "blocks": [ + { + "bbox": [ + 59, + 214, + 194, + 224 + ], + "lines": [ + { + "bbox": [ + 59, + 214, + 194, + 224 + ], + "spans": [ + { + "bbox": [ + 59, + 214, + 194, + 224 + ], + "type": "text", + "content": "(e) The depth of the adaptive decoder " + }, + { + "bbox": [ + 59, + 214, + 194, + 224 + ], + "type": "inline_equation", + "content": "N" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 217, + 157, + 358, + 211 + ], + "lines": [ + { + "bbox": [ + 217, + 157, + 358, + 211 + ], + "spans": [ + { + "bbox": [ + 217, + 157, + 358, + 211 + ], + "type": "table", + "html": "
Masked ConvolutionmAPAP50AP75
Baseline37.456.739.6
w/o39.658.842.5
w/39.959.342.5
", + "image_path": "0ad2b3df24c1b02a633e29d003db0e34b0d14853d3e2450db3eba75183fa72a7.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 383, + 157, + 531, + 212 + ], + "blocks": [ + { + "bbox": [ + 238, + 214, + 332, + 223 + ], + "lines": [ + { + "bbox": [ + 238, + 214, + 332, + 223 + ], + "spans": [ + { + "bbox": [ + 238, + 214, + 332, + 223 + ], + "type": "text", + "content": "(f) The masked convolution." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 383, + 157, + 531, + 212 + ], + "lines": [ + { + "bbox": [ + 383, + 157, + 531, + 212 + ], + "spans": [ + { + "bbox": [ + 383, + 157, + 531, + 212 + ], + "type": "table", + "html": "
Mask StrategymAPAP50AP75
Baseline37.456.739.6
Random39.959.342.5
Grid37.857.040.2
Block39.759.242.7
", + "image_path": "661911048174227844c05195f40c7373ace63a7ae69ad6d0a86529592d34f485.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_body" + } + ], + "index": 12 + }, + { + "type": "table", + "bbox": [ + 81, + 274, + 256, + 450 + ], + "blocks": [ + { + "bbox": [ + 411, + 214, + 496, + 224 + ], + "lines": [ + { + "bbox": [ + 411, + 214, + 496, + 224 + ], + "spans": [ + { + "bbox": [ + 411, + 214, + 496, + 224 + ], + "type": "text", + "content": "(g) The masking strategy." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 46, + 233, + 545, + 269 + ], + "lines": [ + { + "bbox": [ + 46, + 233, + 545, + 269 + ], + "spans": [ + { + "bbox": [ + 46, + 233, + 545, + 269 + ], + "type": "text", + "content": "Table 4: Ablation study on the MKD design with RetinaNet-ResNet50 as student and RetinaNet-ResNeXt101 as a teacher under 1x training schedule. If not specified, the patch size is 32, " + }, + { + "bbox": [ + 46, + 233, + 545, + 269 + ], + "type": "inline_equation", + "content": "\\lambda = 3" + }, + { + "bbox": [ + 46, + 233, + 545, + 269 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 233, + 545, + 269 + ], + "type": "inline_equation", + "content": "\\gamma = 3e - 6" + }, + { + "bbox": [ + 46, + 233, + 545, + 269 + ], + "type": "text", + "content": ", the decoder has a depth of 4, and the mask is randomly sampled." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 81, + 274, + 256, + 450 + ], + "lines": [ + { + "bbox": [ + 81, + 274, + 256, + 450 + ], + "spans": [ + { + "bbox": [ + 81, + 274, + 256, + 450 + ], + "type": "table", + "html": "
MethodinputsizemIoU
PspNet-Res101(T)512x102478.34
PspNet-Res18(S)512x51269.85
SKDS [25]512x51272.70
CWD [30]512x51273.53
MGD [41]512x51273.63
MGD* [41]512x51274.10
ours512x51273.99
ours*512x51274.70
PspNet-Res101(T)512x102478.34
DeepLabV3-Res18(S)512x51273.20
SKDS [25]512x51273.87
CWD [30]512x51275.93
MGD [41]512x51276.02
MGD* [41]512x51276.31
ours512x51276.14
ours*512x51276.63
", + "image_path": "d37b28f2852a2712f369c275d5029808eeccc0d751e618ecc913f3e364101c65.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "table_body" + } + ], + "index": 15 + }, + { + "type": "table", + "bbox": [ + 93, + 488, + 243, + 564 + ], + "blocks": [ + { + "bbox": [ + 47, + 459, + 286, + 483 + ], + "lines": [ + { + "bbox": [ + 47, + 459, + 286, + 483 + ], + "spans": [ + { + "bbox": [ + 47, + 459, + 286, + 483 + ], + "type": "text", + "content": "Table 5: Semantic segmentation result on Cityscape dataset. * means adopting an extra logits loss from CWD [30]." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 93, + 488, + 243, + 564 + ], + "lines": [ + { + "bbox": [ + 93, + 488, + 243, + 564 + ], + "spans": [ + { + "bbox": [ + 93, + 488, + 243, + 564 + ], + "type": "table", + "html": "
MethodTop-1Top-5
ResNet-34(T)73.6291.59
ResNet-18(S)69.9089.43
FitNet [29]71.5090.27
SRRL [39]71.7390.60
MGD [41]71.8090.40
Ours72.0190.43
", + "image_path": "bf9f0c980b3601bf3183164003826d3aa837823553309687204ec12a4d1eb536.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "table_body" + } + ], + "index": 17 + }, + { + "bbox": [ + 52, + 573, + 281, + 586 + ], + "lines": [ + { + "bbox": [ + 52, + 573, + 281, + 586 + ], + "spans": [ + { + "bbox": [ + 52, + 573, + 281, + 586 + ], + "type": "text", + "content": "Table 6: The performance of classification on ImageNet." + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 47, + 594, + 234, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 594, + 234, + 605 + ], + "spans": [ + { + "bbox": [ + 47, + 594, + 234, + 605 + ], + "type": "text", + "content": "optimization steps for the student to converge." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "content": "Masked convolution. To keep the masked patches not affected by others in the convolution block, we introduce the masked convolution in our MKD, and the results of ablation on masked convolution are shown in Tab. 4f. Removing masked convolution from MKD will lead to a reduction of " + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "inline_equation", + "content": "0.3\\mathrm{mAP}" + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "content": ", which is still better than that of the baseline. This demonstrates that the masking operation indeed hinders the optimization of convolution blocks, and adopting masked convolution can effectively alleviate this issue." + } + ] + } + ], + "index": 20 + }, + { + "type": "image", + "bbox": [ + 353, + 287, + 485, + 386 + ], + "blocks": [ + { + "bbox": [ + 353, + 287, + 485, + 386 + ], + "lines": [ + { + "bbox": [ + 353, + 287, + 485, + 386 + ], + "spans": [ + { + "bbox": [ + 353, + 287, + 485, + 386 + ], + "type": "image", + "image_path": "84731a4abba1ba636fe5472e2fd61320167eb230298fa464046634fda03591ef.jpg" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 389, + 545, + 437 + ], + "lines": [ + { + "bbox": [ + 305, + 389, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 305, + 389, + 545, + 437 + ], + "type": "text", + "content": "Figure 7: Illustration of the performance improvement of different masking ratios under different schedules. It appears that MKD (green) brings the greatest boost to the baseline (36.5mAP)." + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_caption" + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 460, + 545, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 460, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 304, + 460, + 545, + 555 + ], + "type": "text", + "content": "Mask patch size. Here we examine how the masked patch size influences the distillation process. As shown in Tab. 4a, a patch size of 32 performs the best than other options. A smaller patch will lead to the confusing assignment of masked position in the last stage, which leads to inferior performance. On the contrary, using a larger patch size may distort the objects too much and make the edge vague. So we use a masked patch size of 32 by default in our work." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 304, + 556, + 545, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 556, + 545, + 640 + ], + "spans": [ + { + "bbox": [ + 304, + 556, + 545, + 640 + ], + "type": "text", + "content": "SAM and SRM. We compare different aligned resolutions in SAM, and the results are shown in Tab. 4b. The training process appears to be out of memory(OOM) without spatial alignment operation, indicating that SAM and SRM are important in reducing computation and memory. We further found that setting the target resolution as " + }, + { + "bbox": [ + 304, + 556, + 545, + 640 + ], + "type": "inline_equation", + "content": "\\frac{H}{32} \\times \\frac{W}{32}" + }, + { + "bbox": [ + 304, + 556, + 545, + 640 + ], + "type": "text", + "content": " performs the best because it is the same size as the masked patches." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": "Mask sampling strategies. Here we examine the influence of different masking strategies, e.g., masking randomly, masking in grids, and masking by block. Recent masked image modeling works show that random strategy works the best, and we observe a similar trend in our MKD. Note that to prevent the student network from learning the mask pat" + } + ] + } + ], + "index": 25 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "6391" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 108 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 108 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 108 + ], + "type": "text", + "content": "tern, it is necessary to use a global random mask. As shown in Tab. 4g, random masking surpasses other ways and is selected in other experiments in this paper." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 109, + 287, + 238 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 109, + 287, + 238 + ], + "spans": [ + { + "bbox": [ + 46, + 109, + 287, + 238 + ], + "type": "text", + "content": "Adaptive decoder design. Adaptive decoder helps to reconstruct masked features from visible ones and is an important module in MKD. We choose different numbers of decoder layers and examine their effects on distillation performance. As shown in Tab. 4e, four layers perform the best. Due to the feature dimension and length of the sequence, we use four layers by default. Objects of different scales correspond to different feature levels of FPN, so we use unshared tokens for the reconstruction. While shared tokens cause a performance drop from " + }, + { + "bbox": [ + 46, + 109, + 287, + 238 + ], + "type": "inline_equation", + "content": "37.3\\mathrm{mAP}" + }, + { + "bbox": [ + 46, + 109, + 287, + 238 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 109, + 287, + 238 + ], + "type": "inline_equation", + "content": "37.0\\mathrm{mAP}" + }, + { + "bbox": [ + 46, + 109, + 287, + 238 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "spans": [ + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": "Loss weight. In Eq. 5, we use two hyper-parameters " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": " to balance the distillation loss, and we conduct ablation studies to investigate their sensitivities of them. From Tab. 4d and 4c, it can be seen that the performance of the student model is not sensitive to the choices of " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": ", as the gap between the worst and the best is within " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "0.2\\mathrm{mAP}" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": ". Note that " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "L_{feat}" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "L_{global}" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": " are both distillation losses to calculate the similarity between the reconstructed output of the decoder " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "\\hat{F}^S" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": " and teacher feature " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "F^T" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": ". The main difference is that " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "L_{feat}" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": " directly calculates MSE, and " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "L_{global}" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": " goes through a GCblock. Hence, the performance drop is small when " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "\\lambda = 0" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "inline_equation", + "content": "\\gamma = 0" + }, + { + "bbox": [ + 46, + 239, + 288, + 395 + ], + "type": "text", + "content": ", as MKD already works when using either of the loss alone." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 406, + 119, + 418 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 406, + 119, + 418 + ], + "spans": [ + { + "bbox": [ + 47, + 406, + 119, + 418 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 426, + 287, + 582 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 426, + 287, + 582 + ], + "spans": [ + { + "bbox": [ + 46, + 426, + 287, + 582 + ], + "type": "text", + "content": "In this paper, we propose a new distillation paradigm Masked Knowledge Distillation (MKD), which introduces the masked autoencoding scheme to enhance the knowledge distillation process. MKD takes the masked image as input and predicts the whole feature map that is used to imitate the corresponding feature of the teacher network. By forcing the student network to learn the knowledge of the nearby region of the masked part to recover the full feature, the student can better transfer the corresponding information from the teacher, which helps to excavate the potential of the small student network. Extensive experimental results on various fine-grained visual tasks show its power in enhancing the improvement of knowledge distillation." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 593, + 145, + 606 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 593, + 145, + 606 + ], + "spans": [ + { + "bbox": [ + 47, + 593, + 145, + 606 + ], + "type": "text", + "content": "Acknowledgement" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 612, + 287, + 661 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 612, + 287, + 661 + ], + "spans": [ + { + "bbox": [ + 46, + 612, + 287, + 661 + ], + "type": "text", + "content": "This work was partly supported by the National Natural Science Foundation of China (Grant No. 61991451) and the Shenzhen Science and Technology Program (JCYJ20220818101001004)." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 671, + 106, + 684 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 671, + 106, + 684 + ], + "spans": [ + { + "bbox": [ + 47, + 671, + 106, + 684 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 52, + 691, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 691, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 52, + 691, + 287, + 713 + ], + "type": "text", + "content": "[1] Guobin Chen, Wongun Choi, Xiang Yu, Tony Han, and Manmohan Chandraker. Learning efficient object detection mod" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 307, + 73, + 547, + 712 + ], + "type": "list", + "angle": 0, + "index": 25, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 94 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 94 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 94 + ], + "type": "text", + "content": "els with knowledge distillation. In NIPS, pages 742-751, 2017. 2, 3, 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 311, + 96, + 547, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 96, + 547, + 150 + ], + "spans": [ + { + "bbox": [ + 311, + 96, + 547, + 150 + ], + "type": "text", + "content": "[2] Kai Chen, Jiaqi Wang, Jiangmiao Pang, Yuhang Cao, Yu Xiong, Xiaoxiao Li, Shuyang Sun, Wansen Feng, Ziwei Liu, Jiarui Xu, et al. Mmdetection: Open mmlab detection toolbox and benchmark. arXiv preprint arXiv:1906.07155, 2019. 6" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 311, + 152, + 547, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 152, + 547, + 194 + ], + "spans": [ + { + "bbox": [ + 311, + 152, + 547, + 194 + ], + "type": "text", + "content": "[3] Liang-Chieh Chen, George Papandreou, Florian Schroff, and Hartwig Adam. Rethinking atrous convolution for semantic image segmentation. arXiv preprint arXiv:1706.05587, 2017. 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 311, + 197, + 547, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 197, + 547, + 228 + ], + "spans": [ + { + "bbox": [ + 311, + 197, + 547, + 228 + ], + "type": "text", + "content": "[4] Pengguang Chen, Shu Liu, Hengshuang Zhao, and Jiaya Jia. Distilling knowledge via knowledge review. In CVPR, pages 5008-5017, 2021. 1, 5" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 311, + 230, + 547, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 230, + 547, + 274 + ], + "spans": [ + { + "bbox": [ + 311, + 230, + 547, + 274 + ], + "type": "text", + "content": "[5] MMSegmentation Contributors. Mmsegmentation: Openmmlab semantic segmentation toolbox and benchmark. https://github.com/open-mmlab/mmsegmentation, 2020.6" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 311, + 276, + 547, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 276, + 547, + 330 + ], + "spans": [ + { + "bbox": [ + 311, + 276, + 547, + 330 + ], + "type": "text", + "content": "[6] Marius Cordts, Mohamed Omran, Sebastian Ramos, Timo Rehfeld, Markus Enzweiler, Rodrigo Benenson, Uwe Franke, Stefan Roth, and Bernt Schiele. The cityscapes dataset for semantic urban scene understanding. In CVPR, pages 3213-3223, 2016. 6" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 311, + 331, + 547, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 331, + 547, + 374 + ], + "spans": [ + { + "bbox": [ + 311, + 331, + 547, + 374 + ], + "type": "text", + "content": "[7] Xing Dai, Zeren Jiang, Zhao Wu, Yiping Bao, Zhicheng Wang, Si Liu, and Erjin Zhou. General instance distillation for object detection. In CVPR, pages 7842-7851, 2021. 1, 3, 5, 6, 7" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 311, + 376, + 545, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 376, + 545, + 430 + ], + "spans": [ + { + "bbox": [ + 311, + 376, + 545, + 430 + ], + "type": "text", + "content": "[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In ICLR, 2020. 4" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 311, + 432, + 545, + 464 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 432, + 545, + 464 + ], + "spans": [ + { + "bbox": [ + 311, + 432, + 545, + 464 + ], + "type": "text", + "content": "[9] Kaiwen Duan, Song Bai, Lingxi Xie, Honggang Qi, Qingming Huang, and Qi Tian. Centernet: Keypoint triplets for object detection. In ICCV, pages 6569-6578, 2019. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 466, + 545, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 466, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 307, + 466, + 545, + 498 + ], + "type": "text", + "content": "[10] Peng Gao, Teli Ma, Hongsheng Li, Jifeng Dai, and Yu Qiao. Convmae: Masked convolution meets masked autoencoders. arXiv preprint arXiv:2205.03892, 2022. 2, 4" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 500, + 545, + 553 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 500, + 545, + 553 + ], + "spans": [ + { + "bbox": [ + 307, + 500, + 545, + 553 + ], + "type": "text", + "content": "[11] Kunyang Han, Yong Liu, Jun Hao Liew, Henghui Ding, Yunchao Wei, Jiajun Liu, Yitong Wang, Yansong Tang, Yujiu Yang, Jiashi Feng, et al. Global knowledge calibration for fast open-vocabulary segmentation. arXiv preprint arXiv:2303.09181, 2023. 1" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 555, + 545, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 555, + 545, + 588 + ], + "spans": [ + { + "bbox": [ + 307, + 555, + 545, + 588 + ], + "type": "text", + "content": "[12] Song Han, Jeff Pool, John Tran, and William Dally. Learning both weights and connections for efficient neural network. NIPS, 28, 2015. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 590, + 545, + 622 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 590, + 545, + 622 + ], + "spans": [ + { + "bbox": [ + 307, + 590, + 545, + 622 + ], + "type": "text", + "content": "[13] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollar, and Ross Girshick. Masked autoencoders are scalable vision learners. In CVPR, pages 16000-16009, 2022. 4" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 624, + 545, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 624, + 545, + 645 + ], + "spans": [ + { + "bbox": [ + 307, + 624, + 545, + 645 + ], + "type": "text", + "content": "[14] Kaiming He, Georgia Gkioxari, Piotr Dólar, and Ross Girshick. Mask r-cnn. In ICCV, pages 2961-2969, 2017. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 647, + 545, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 647, + 545, + 679 + ], + "spans": [ + { + "bbox": [ + 307, + 647, + 545, + 679 + ], + "type": "text", + "content": "[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778, 2016. 1" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 681, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 681, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 681, + 545, + 712 + ], + "type": "text", + "content": "[16] Geoffrey Hinton, Oriol Vinyals, and Jeff Dean. Distilling the knowledge in a neural network. Computer Science, 14(7):38-39, 2015. 1, 3" + } + ] + } + ], + "index": 24 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6392" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 115 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 115 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 115 + ], + "type": "text", + "content": "[17] Zijian Kang, Peizhen Zhang, Xiangyu Zhang, Jian Sun, and Nanning Zheng. Instance-conditional knowledge distillation for object detection. NIPS, 34:16468-16480, 2021. 1, 3, 5, 7" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 118, + 287, + 151 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 118, + 287, + 151 + ], + "spans": [ + { + "bbox": [ + 49, + 118, + 287, + 151 + ], + "type": "text", + "content": "[18] Quanquan Li, Shengying Jin, and Junjie Yan. Mimicking very efficient network for object detection. In CVPR, pages 6356-6364, 2017. 1" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 153, + 287, + 186 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 153, + 287, + 186 + ], + "spans": [ + { + "bbox": [ + 49, + 153, + 287, + 186 + ], + "type": "text", + "content": "[19] Rundong Li, Yan Wang, Feng Liang, Hongwei Qin, Junjie Yan, and Rui Fan. Fully quantized network for object detection. In CVPR, pages 2810-2819, 2019. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 188, + 287, + 231 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 188, + 287, + 231 + ], + "spans": [ + { + "bbox": [ + 49, + 188, + 287, + 231 + ], + "type": "text", + "content": "[20] Tsung-Yi Lin, Piotr Dólar, Ross Girshick, Kaiming He, Bharath Hariharan, and Serge Belongie. Feature pyramid networks for object detection. In CVPR, pages 2117-2125, 2017. 1" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 233, + 287, + 266 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 233, + 287, + 266 + ], + "spans": [ + { + "bbox": [ + 49, + 233, + 287, + 266 + ], + "type": "text", + "content": "[21] Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dólar. Focal loss for dense object detection. In ICCV, pages 2980-2988, 2017. 3, 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 269, + 287, + 312 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 269, + 287, + 312 + ], + "spans": [ + { + "bbox": [ + 49, + 269, + 287, + 312 + ], + "type": "text", + "content": "[22] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dálár, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In ECCV, pages 740-755. Springer, 2014. 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 314, + 287, + 357 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 314, + 287, + 357 + ], + "spans": [ + { + "bbox": [ + 49, + 314, + 287, + 357 + ], + "type": "text", + "content": "[23] Guilin Liu, Fitsum A Reda, Kevin J Shih, Ting-Chun Wang, Andrew Tao, and Bryan Catanzaro. Image inpainting for irregular holes using partial convolutions. In ECCV, pages 85-100, 2018. 2, 4" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 359, + 287, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 359, + 287, + 403 + ], + "spans": [ + { + "bbox": [ + 49, + 359, + 287, + 403 + ], + "type": "text", + "content": "[24] Wei Liu, Dragomir Anguelov, Dumitru Erhan, Christian Szegedy, Scott Reed, Cheng-Yang Fu, and Alexander C Berg. Ssd: Single shot multibox detector. In ECCV, pages 21-37. Springer, 2016. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 405, + 287, + 448 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 405, + 287, + 448 + ], + "spans": [ + { + "bbox": [ + 49, + 405, + 287, + 448 + ], + "type": "text", + "content": "[25] Yifan Liu, Ke Chen, Chris Liu, Zengchang Qin, Zhenbo Luo, and Jingdong Wang. Structured knowledge distillation for semantic segmentation. In CVPR, pages 2604-2613, 2019. 8" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 450, + 287, + 494 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 450, + 287, + 494 + ], + "spans": [ + { + "bbox": [ + 49, + 450, + 287, + 494 + ], + "type": "text", + "content": "[26] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In ICCV, pages 10012-10022, 2021. 6" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 496, + 287, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 496, + 287, + 529 + ], + "spans": [ + { + "bbox": [ + 49, + 496, + 287, + 529 + ], + "type": "text", + "content": "[27] Mengye Ren, Andrei Pokrovsky, Bin Yang, and Raquel Urtasun. Sbnet: Sparse blocks network for fast inference. In CVPR, pages 8711-8720, 2018. 4" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 49, + 531, + 287, + 563 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 531, + 287, + 563 + ], + "spans": [ + { + "bbox": [ + 49, + 531, + 287, + 563 + ], + "type": "text", + "content": "[28] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. NIPS, 28, 2015. 3, 6" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 49, + 566, + 287, + 608 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 566, + 287, + 608 + ], + "spans": [ + { + "bbox": [ + 49, + 566, + 287, + 608 + ], + "type": "text", + "content": "[29] Adriana Romero, Nicolas Ballas, Samira Ebrahimi Kahou, Antoine Chassang, Carlo Gatta, and Yoshua Bengio. Fitnets: Hints for thin deep nets. arXiv preprint arXiv:1412.6550, 2014. 1, 3, 5, 8" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 49, + 611, + 287, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 611, + 287, + 643 + ], + "spans": [ + { + "bbox": [ + 49, + 611, + 287, + 643 + ], + "type": "text", + "content": "[30] Changyong Shu, Yifan Liu, Jianfei Gao, Zheng Yan, and Chunhua Shen. Channel-wise knowledge distillation for dense prediction. In ICCV, pages 5311-5320, 2021. 8" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 49, + 646, + 287, + 677 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 646, + 287, + 677 + ], + "spans": [ + { + "bbox": [ + 49, + 646, + 287, + 677 + ], + "type": "text", + "content": "[31] Mingxing Tan, Ruoming Pang, and Quoc V Le. Efficientdet: Scalable and efficient object detection. In CVPR, pages 10781-10790, 2020. 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 49, + 680, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 680, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 49, + 680, + 287, + 713 + ], + "type": "text", + "content": "[32] Zhi Tian, Chunhua Shen, Hao Chen, and Tong He. Fcos: Fully convolutional one-stage object detection. In ICCV, pages 9627-9636, 2019. 3" + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 624 + ], + "type": "list", + "angle": 0, + "index": 32, + "blocks": [ + { + "bbox": [ + 308, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 308, + 73, + 545, + 106 + ], + "type": "text", + "content": "[33] Jiahao Wang, Mingdeng Cao, Shuwei Shi, Baoyuan Wu, and Yujiu Yang. Attention probe: Vision transformer distillation in the wild. In ICASSP, pages 2220-2224. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 107, + 545, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 107, + 545, + 140 + ], + "spans": [ + { + "bbox": [ + 308, + 107, + 545, + 140 + ], + "type": "text", + "content": "[34] Tao Wang, Li Yuan, Xiaopeng Zhang, and Jiashi Feng. Distilling object detectors with fine-grained feature imitation. In CVPR, pages 4933-4942, 2019. 1, 2, 3, 5, 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 141, + 545, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 141, + 545, + 173 + ], + "spans": [ + { + "bbox": [ + 308, + 141, + 545, + 173 + ], + "type": "text", + "content": "[35] Xinlong Wang, Rufeng Zhang, Tao Kong, Lei Li, and Chunhua Shen. Solov2: Dynamic and fast instance segmentation. NIPS, 33:17721-17732, 2020. 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 175, + 545, + 207 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 175, + 545, + 207 + ], + "spans": [ + { + "bbox": [ + 308, + 175, + 545, + 207 + ], + "type": "text", + "content": "[36] Yi Wei, Xinyu Pan, Hongwei Qin, Wanli Ouyang, and Junjie Yan. Quantization mimic: Towards very tiny cnn for object detection. In ECCV, pages 267-283, 2018. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 209, + 545, + 241 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 209, + 545, + 241 + ], + "spans": [ + { + "bbox": [ + 308, + 209, + 545, + 241 + ], + "type": "text", + "content": "[37] Taiqiang Wu, Cheng Hou, Zhe Zhao, Shanshan Lao, Jiayi Li, Ngai Wong, and Yujiu Yang. Weight-inherited distillation for task-agnostic bert compression, 2023. 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 243, + 545, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 243, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 308, + 243, + 545, + 285 + ], + "type": "text", + "content": "[38] Xiang Xiang, Zhiyuan Wang, Shanshan Lao, and Baochang Zhang. Pruning multi-view stereo net for efficient 3d reconstruction. ISPRS Journal of Photogrammetry and Remote Sensing, 168:17-27, 2020. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 287, + 545, + 319 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 287, + 545, + 319 + ], + "spans": [ + { + "bbox": [ + 308, + 287, + 545, + 319 + ], + "type": "text", + "content": "[39] Jing Yang, Brais Martinez, Adrian Bulat, Georgios Tzimiropoulos, et al. Knowledge distillation via softmax regression representation learning. ICLR, 2021. 8" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 322, + 545, + 364 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 322, + 545, + 364 + ], + "spans": [ + { + "bbox": [ + 308, + 322, + 545, + 364 + ], + "type": "text", + "content": "[40] Zhendong Yang, Zhe Li, Xiaohu Jiang, Yuan Gong, Zehuan Yuan, Danpei Zhao, and Chun Yuan. Focal and global knowledge distillation for detectors. In CVPR, pages 4643-4652, 2022. 1, 2, 3, 5, 6, 7" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 366, + 545, + 399 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 366, + 545, + 399 + ], + "spans": [ + { + "bbox": [ + 308, + 366, + 545, + 399 + ], + "type": "text", + "content": "[41] Zhendong Yang, Zhe Li, Mingqi Shao, Dachuan Shi, Zehuan Yuan, and Chun Yuan. Masked generative distillation. arXiv preprint arXiv:2205.01529, 2022. 3, 5, 6, 7, 8" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 400, + 545, + 433 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 400, + 545, + 433 + ], + "spans": [ + { + "bbox": [ + 308, + 400, + 545, + 433 + ], + "type": "text", + "content": "[42] Zhendong Yang, Zhe Li, Ailing Zeng, Zexian Li, Chun Yuan, and Yu Li. Vitkd: Practical guidelines for vit feature knowledge distillation. arXiv preprint arXiv:2209.02432, 2022. 3" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 434, + 545, + 466 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 434, + 545, + 466 + ], + "spans": [ + { + "bbox": [ + 308, + 434, + 545, + 466 + ], + "type": "text", + "content": "[43] Ze Yang, Shaohui Liu, Han Hu, Liwei Wang, and Stephen Lin. Repoints: Point set representation for object detection. In ICCV, pages 9657-9666, 2019. 3, 6" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 468, + 545, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 468, + 545, + 521 + ], + "spans": [ + { + "bbox": [ + 308, + 468, + 545, + 521 + ], + "type": "text", + "content": "[44] Zhendong Yang, Ailing Zeng, Zhe Li, Tianke Zhang, Chun Yuan, and Yu Li. From knowledge distillation to self-knowledge distillation: A unified approach with normalized loss and customized soft labels. arXiv preprint arXiv:2303.13005, 2023. 3" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 524, + 545, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 524, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 308, + 524, + 545, + 555 + ], + "type": "text", + "content": "[45] Linfeng Zhang and Kaisheng Ma. Improve object detection with feature-based knowledge distillation: Towards accurate and efficient detectors. In ICLR, 2020. 1, 3, 5, 6, 7" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 308, + 557, + 545, + 590 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 557, + 545, + 590 + ], + "spans": [ + { + "bbox": [ + 308, + 557, + 545, + 590 + ], + "type": "text", + "content": "[46] Borui Zhao, Quan Cui, Renjie Song, Yiyu Qiu, and Jiajun Liang. Decoupled knowledge distillation. In CVPR, pages 11953-11962, 2022. 1, 2, 3" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 308, + 591, + 545, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 591, + 545, + 624 + ], + "spans": [ + { + "bbox": [ + 308, + 591, + 545, + 624 + ], + "type": "text", + "content": "[47] Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, and Jiaya Jia. Pyramid scene parsing network. In CVPR, pages 2881-2890, 2017. 7" + } + ] + } + ], + "index": 31 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "6393" + } + ] + } + ], + "index": 33 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Masked Autoencoders are Efficient Class Incremental Learners/3431d5c0-b1b6-47da-9e6e-bca6fba5a382_content_list.json b/2023/Masked Autoencoders are Efficient Class Incremental Learners/3431d5c0-b1b6-47da-9e6e-bca6fba5a382_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..7c56bddc5eb5f1af4975dc7fe3a48d6dae659c58 --- /dev/null +++ b/2023/Masked Autoencoders are Efficient Class Incremental Learners/3431d5c0-b1b6-47da-9e6e-bca6fba5a382_content_list.json @@ -0,0 +1,1742 @@ +[ + { + "type": "text", + "text": "Masked Autoencoders are Efficient Class Incremental Learners", + "text_level": 1, + "bbox": [ + 163, + 130, + 805, + 150 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Jiang-Tian Zhai $^{1}$ Xialei Liu $^{1,*}$ Andrew D. Bagdanov $^{2}$ Ke Li $^{3}$ Ming-Ming Cheng $^{1}$ VCIP, CS, Nankai University $^{2}$ MICC, University of Florence $^{3}$ Tencent Youtu Lab", + "bbox": [ + 116, + 179, + 849, + 217 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 251, + 313, + 266 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Class Incremental Learning (CIL) aims to sequentially learn new classes while avoiding catastrophic forgetting of previous knowledge. We propose to use Masked Autoencoders (MAEs) as efficient learners for CIL. MAEs were originally designed to learn useful representations through reconstructive unsupervised learning, and they can be easily integrated with a supervised loss for classification. Moreover, MAEs can reliably reconstruct original input images from randomly selected patches, which we use to store exemplars from past tasks more efficiently for CIL. We also propose a bilateral MAE framework to learn from image-level and embedding-level fusion, which produces better-quality reconstructed images and more stable representations. Our experiments confirm that our approach performs better than the state-of-the-art on CIFAR-100, ImageNet-Subset, and ImageNet-Full. The code is available at https://github.com/scok30/MAE-CIL.", + "bbox": [ + 75, + 282, + 473, + 540 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 580, + 209, + 598 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Deep learning has had a broad and deep impact on most computer vision tasks over the last ten years. Given the way humans learn continually in their lifespan, it is natural to expect models also to be able to accumulate knowledge and build on past experiences to adapt to new tasks incrementally. The real world is very dynamic, leading to varying data distributions over time, while deep models tend to catastrophically forget old tasks when learning new ones [26].", + "bbox": [ + 75, + 607, + 468, + 743 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Class Incremental Learning (CIL) aims to learn new classification tasks sequentially while avoiding catastrophic forgetting [2, 25]. CIL approaches can be roughly divided into three categories [5], i.e., Rehearsal-based methods [13, 29, 31], Regularization-based methods [15, 17], and Architecture-based methods [1, 23, 24]. Among them, Rehearsal-based methods achieve state-of-the-art performance by storing exemplars from past tasks or generating synthetic samples for replay.", + "bbox": [ + 75, + 743, + 470, + 878 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/1e7fdd29b007c374d0bd78f9399d702c2c5fd848fe24d73c8eaf7b7bfe969c57.jpg", + "image_caption": [ + "Figure 1. Our proposed bilateral MAE for efficient CIL. The Replay Buffer contains random patches selected from past task images, which is more efficient than storing whole images. Combining these with masked input data from the current task, the MAE simultaneously learns to classify and reconstruct images from the masked input. To further improve the reconstructed image quality and learned representations, embedding-level and image-level fusion is used to learn more stable representations and more detailed reconstructions for CIL." + ], + "image_footnote": [], + "bbox": [ + 501, + 248, + 893, + 415 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Normally, only a fixed size of memory is allowed during incremental learning. Therefore, it limits the stored exemplars from past tasks. Other works exploit generative networks [35, 38, 43] (e.g., GANs) to synthesize samples from old tasks for replay. Although they can generate replay data to mitigate forgetting, a typical drawback is the quality of generated images, and that forgetting can also happen in generative models. In this work, we introduce Masked Autoencoders (MAEs) [11] as a base model to replay. It allows efficient exemplar storage by only requiring a small subset of patches to reconstruct whole images. Therefore, we can store more exemplars with the same amount of limited memory as other exemplar-based approaches. Compared to previous generative methods, replay by MAE is more stable because it uses partial cues to infer global information, which is task-agnostic and suffers less forgetting across tasks. This relieves the unstable generation effect of GANs across tasks with stationary image patches.", + "bbox": [ + 496, + 566, + 893, + 839 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Masked Autoencoders (MAEs) [11] were initially proposed to learn better feature representations in self-supervised learning scenarios. In this work, we see it as efficient incremental learners and propose a novel bilat", + "bbox": [ + 496, + 839, + 893, + 900 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding author (xialei@nankai.edu.cn)", + "bbox": [ + 94, + 886, + 346, + 900 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "19104", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "eral transformer architecture for efficient exemplar replay in CIL. Our main idea is simple: by randomly masking patches of input images and training models to reconstruct the masked pixels, MAEs can provide a new form of self-supervised representation learning for CIL and thus learn more generalizable representations essential for CIL. In addition, leveraging a supervised objective with classification labels benefits unsupervised MAE in training efficiency and model robustness [18]. Masked inputs can also serve as strong classification regularization by only providing a random subset of data.", + "bbox": [ + 75, + 90, + 472, + 256 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "When learning new tasks, the MAE can coarsely reconstruct images from sparsely sampled patches from exemplars. This process enables the framework to generate reconstructed replay data, but two problems remain: (i) the generated images tend to have less detailed and less realistic textures, which reduces data diversity for replay; and (ii) on the embedding-level, the linear classifier lacks information from low-level features. Therefore, we introduce a bilateral MAE framework with image-level and embedding-level fusion for CIL (see Fig. 1 for a schematic overview). Fusing a complementary detailed and reconstructed image alleviates catastrophic forgetting by enriching the insufficient replay data with detailed, high-quality data distributions. Embedding-level fusion from the two branches also maintains stable and diverse embeddings, and our framework can thus achieve a better trade-off between plasticity and stability.", + "bbox": [ + 75, + 257, + 472, + 513 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The main contributions of our bilateral MAE framework are threefold:", + "bbox": [ + 76, + 513, + 468, + 544 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We introduce an MAE framework for efficient incremental learning that incorporates benefits from both self-supervised reconstruction and data generation for replay.", + "- To further boost the quality of reconstructed images and learning efficiency, we design a novel bilateral MAE with two complementary branches for better-reconstructed images and regularized representations.", + "- Our approach achieves state-of-the-art performance under different CIL settings on CIFAR-100, ImageNet-Subset, and ImageNet-Full." + ], + "bbox": [ + 94, + 549, + 468, + 732 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 76, + 744, + 218, + 758 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Incremental learning. Various methods have been proposed for incremental learning in the past few years [2, 5]. Recent works can be coarsely grouped into three categories: replay-based, regularization-based, and parameter-isolation methods. Replay-based methods mitigate the task-recency bias by replaying training samples from previous tasks. In addition to replaying samples, BiC [36], PODNet [8], and iCaRL [29] apply a distillation loss to prevent forgetting and enhance model stability. GEM [21], AGEM [3],", + "bbox": [ + 75, + 763, + 472, + 902 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "and MER [30] exploit past-task exemplars by modifying gradients on current training samples to match old samples. Rehearsal-based methods may cause models to overfit stored samples.", + "bbox": [ + 496, + 90, + 890, + 151 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Pseudo-replay methods reconstruct the old data for replay. MeRGANs [35] use conditional GANs to balance the generation of old and current samples. Besides, dreamingrelevant methods like DeepInversion [41] and AlwaysBeDreaming [33] exploit backward signals to generate images similar to the original datasets.", + "bbox": [ + 496, + 151, + 890, + 242 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Regularization-based approaches, such as LwF [17], EWC [15], and DMC [44], offer methods to learn better representations while leaving enough plasticity for adaptation to new tasks. Parameter-isolation methods [24,39] use models with different computational graphs for each task. With the help of growing models, new model branches mitigate catastrophic forgetting at the cost of more parameters and computational costs.", + "bbox": [ + 496, + 242, + 890, + 363 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Self-Supervised Learning. Self-supervised learning [7, 27, 37] has been shown to help models learn generalizable features, which makes it natural to consider its application to incremental learning. Early works used pretext tasks like patch permutation [27] or rotation prediction [10]. Contrastive learning approaches model the pairwise similarity and dissimilarity between samples [4]. By comparison, MAEs [11] learn feature representations by reconstructing images from a masked version of inputs.", + "bbox": [ + 496, + 378, + 890, + 513 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "There are a few works proposing self-supervision for class incremental learning. PASS [46] incorporates rotation prediction [10] to learn representations transferable across tasks. DualNet [28] uses Barlow Twins [42] to introduce a \"slow\" task that regularizes the \"fast\" incremental learning. In this paper, we explore the framework generates data for replay while applying semantic and detailed-level self-supervision, which mitigates forgetting via richer replay data and more generalizable features.", + "bbox": [ + 496, + 513, + 890, + 650 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "3. Continual MAE for CIL", + "text_level": 1, + "bbox": [ + 498, + 664, + 728, + 680 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this section, we first define the class incremental learning problem and the basic MAE model. Then we introduce our incremental learning framework and the bilateral MAE architecture it is based on.", + "bbox": [ + 496, + 690, + 890, + 750 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "3.1. Preliminaries", + "text_level": 1, + "bbox": [ + 498, + 760, + 640, + 775 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The class incremental learning problem. CIL aims to sequentially learn tasks with new classes while preventing or alleviating forgetting of old tasks. At a specific phase of learning task $t \\in \\{1,2,\\dots,T\\}$ , model training can exploit only data from the current task $\\{(x_i^t,y_i^t)\\}$ , where $x_{i}^{t}$ denotes image $i$ in task $t$ and $y_{i}^{t}$ its corresponding class label. A CIL model typically consists of a feature extractor $F_{\\theta}$ and a common classifier $G_{\\phi}$ which grows at each new", + "bbox": [ + 496, + 779, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "19105", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/d7ec2e7a634a1a011c36f513c120d12d55c85f74d0f43e3f7ec574b2c7118c6b.jpg", + "image_caption": [ + "Figure 2. Overall framework of our bilateral MAE for CIL. The masked input is passed through two branches with embedding-level fusion for classification and image-level fusion for reconstruction. Full images can be generated from a small sample of input patches and the reconstructed images can be used as replay." + ], + "image_footnote": [], + "bbox": [ + 80, + 89, + 890, + 316 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "task. At task $t + 1$ , $C_{t + 1}$ new classes are added to $G_{\\phi}$ . The feature extractor $F_{\\theta}$ first maps the input $x$ to a deep feature vector $z = F_{\\theta}(x)\\in \\mathbb{R}^{d}$ , where $d$ is the dimension of the output feature representation, and then the unified classifier $G_{\\phi}(z)\\in \\mathbb{R}^{C_{1:t}}$ produces a probability distribution over classes $C_{1:t}$ which is used to make predictions on input $x$ .", + "bbox": [ + 75, + 385, + 468, + 477 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "When training task $t$ , the model aims to minimize losses on the current task without degrading performance on previous tasks. A common technique for mitigating forgetting is to retain a small buffer of training samples from previous tasks. Let $\\epsilon$ be this buffer of previous task samples. One essential problem for CIL is the limited amount of replay data. Compared to the full data of current task $t$ , only a few samples of old task classes are available (20 samples per class is a common setting), which causes imbalanced training between new and old tasks.", + "bbox": [ + 75, + 477, + 468, + 628 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "An MAE framework for classification. An MAE first crops input image $x$ into non-overlapping patches, and we denote the number of patches in the full image $x$ as $N_{f}$ . After patchification, the MAE randomly masks a proportion $r \\in [0,1]$ of the $N_{f}$ patches, leaving only $N = \\lfloor N_{f} \\times (1 - r) \\rfloor$ patches. Then these sampled $K \\times K$ pixel patches are mapped to a visual embedding of dimension $D$ using an MLP. After concatenating with a class token, the result is a tensor of size $\\mathbb{R}^{(N + 1) \\times D}$ . After positionally encoding the original patch locations, this input is passed to the MAE transformer encoder. This operation maintains the same shape of embedding. The output class token embedding can be used for classification with a cross-entropy loss $\\mathcal{L}_t^{\\mathrm{cls}}$ , as shown in Fig. 2.", + "bbox": [ + 76, + 643, + 468, + 854 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "For the MAE Decoder, learnable mask tokens are inserted into the embeddings in place of the masked patches, and the shape of output from the MAE Encoder changes", + "bbox": [ + 75, + 854, + 468, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "from $\\mathbb{R}^{(N + 1)\\times D}$ to $\\mathbb{R}^{(N_f + 1)\\times D}$ . Although the decoder is not used for classification, it helps the network backpropagate image-level reconstruction supervision to the embedding-level. This stabilizes the image embedding and helps the optimization process. Also, the reconstructed images after decoding provide richer, higher-quality replay data. To limit computation, we use a single-layer transformer block for the decoder. The additional classification loss after the encoder speeds up convergence and improves reconstruction efficiency during training. The mean squared error between the input image $x$ and reconstructed image $\\hat{x}$ is used as the reconstruction loss function $\\mathcal{L}_t^{\\mathrm{rec}}(x,\\hat{x})$ .", + "bbox": [ + 496, + 383, + 890, + 568 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Efficient Exemplar Storage with MAEs", + "text_level": 1, + "bbox": [ + 500, + 574, + 836, + 590 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "After training each task, we save small sample images and apply random masking. Keeping the same storage size can save more replay data per class since each sample occupies less space. For example, a masking ratio of 0.75 allows us to save $4 \\times$ the number of (reconstructible) samples compared to conventional replay methods.", + "bbox": [ + 496, + 598, + 890, + 688 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Let $S$ and $P$ denote the size of the image and patch, respectively. Our encoder patchifies the input image into $\\frac{S}{P} \\times \\frac{S}{P}$ patches. We save the 2D index $(i,j)$ for each patch that is not masked. We need only one byte to save these indexes since their range is less than 255. The two additional bytes for saving this 2D index are negligible compared to the saved image patches. A masking ratio 0.75 on a $224 \\times 224$ image requires only 36.75KB of storage. For $P = 16$ , the number of saved patches is $(1 - 0.75) \\times (\\frac{224}{16})^2 = 49$ , and the storage of indexes is only 98B.", + "bbox": [ + 496, + 688, + 890, + 839 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.3. Bilateral MAE Fusion", + "text_level": 1, + "bbox": [ + 500, + 847, + 705, + 861 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To further boost reconstruction quality and embedding diversity, we propose a two-branches MAE to learn global", + "bbox": [ + 500, + 869, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "19106", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/8821003216817f7bb3843edc8f8423a18f766d1c82319b99994a21d92b7d6063.jpg", + "image_caption": [ + "Figure 3. An example of extracting detailed images with reconstructed results from different masking ratios $r_1$ and $r_2$ . The third image comes from the difference between the previous two, and the last image is the extracted high-frequency component from the third image." + ], + "image_footnote": [], + "bbox": [ + 83, + 87, + 460, + 183 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "code", + "code_caption": [ + "Algorithm 1 Pseudocode of our Bilateral MAE." + ], + "code_body": "Input: The number of task $T$ , training samples $D_{t} = \\{(x_{i},y_{i})\\}_{t}$ of task $t$ , model $\\Theta^0$ , replay buffer $\\epsilon$ , and masking ratios $r, r_1, r_2$ .", + "guess_lang": "latex", + "bbox": [ + 76, + 286, + 468, + 330 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "code", + "code_caption": [ + "Output: model $\\Theta^T$" + ], + "code_body": "1: for $t \\in \\{1, 2, \\dots, T\\}$ do", + "guess_lang": "txt", + "bbox": [ + 86, + 347, + 261, + 361 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "code", + "code_caption": [], + "code_body": "2: $\\Theta^t\\gets \\Theta^{t - 1}$", + "guess_lang": "txt", + "bbox": [ + 88, + 362, + 210, + 375 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "code", + "code_caption": [], + "code_body": "3: $R_{t}\\gets \\mathrm{ReconstructOldSamples}(\\epsilon_{t},r)$", + "guess_lang": "javascript", + "bbox": [ + 88, + 378, + 377, + 392 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "code", + "code_caption": [], + "code_body": "4: while not converged do", + "guess_lang": "txt", + "bbox": [ + 88, + 393, + 289, + 407 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "code", + "code_caption": [], + "code_body": "5: $(x,y)\\gets$ Sample $(R_{t},D_{t})$", + "guess_lang": "javascript", + "bbox": [ + 88, + 407, + 328, + 422 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "code", + "code_caption": [], + "code_body": "6: $(\\mathcal{L}_t^{\\mathrm{cls}},\\mathcal{L}_t^{\\mathrm{rec}})\\gets$ BilateralMAE $(x,y)$", + "guess_lang": "txt", + "bbox": [ + 88, + 422, + 388, + 436 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "code", + "code_caption": [], + "code_body": "7: $(\\hat{x}_1, \\hat{x}_2) \\gets \\text{MaskAndReconstruct}(x, r_1, r_2)$", + "guess_lang": "latex", + "bbox": [ + 88, + 438, + 444, + 452 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "code", + "code_caption": [], + "code_body": "8: $\\mathcal{L}_t^{\\mathrm{det}}\\gets$ ComputeDetailLoss $(\\hat{x}_1,\\hat{x}_2)$", + "guess_lang": "txt", + "bbox": [ + 88, + 453, + 398, + 468 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "code", + "code_caption": [], + "code_body": "9: train $\\Theta^t$ by minimizing $\\mathcal{L}_t$ from Eq. 12", + "guess_lang": "txt", + "bbox": [ + 88, + 468, + 413, + 483 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "code", + "code_caption": [], + "code_body": "10: end while", + "guess_lang": "txt", + "bbox": [ + 83, + 484, + 200, + 496 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "code", + "code_caption": [], + "code_body": "11: end for", + "guess_lang": "txt", + "bbox": [ + 83, + 500, + 158, + 511 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "and detailed classification and image reconstruction knowledge. We illustrate the overall framework in Fig. 2. Bilateral fusion at the embedding-level aims to improve representations diversity. Reconstruction learning at the image-level yields high-quality replay data and stable self-supervision for CIL.", + "bbox": [ + 75, + 542, + 468, + 633 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Embedding fusion. In the following we use $F_{\\theta[:1]}$ and $F_{\\theta[1:]}$ to denote our transformer encoder's first and following blocks. Let $H_{\\theta}$ and $E_{\\theta}$ represent the detailed block and embedding fusion module in Fig. 2, which are standard MLP layers and attention blocks, respectively. The classification loss is computed as:", + "bbox": [ + 75, + 652, + 468, + 743 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nf = F _ {\\theta [: 1 ]} (\\operatorname {m a s k} (x, r)) \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 200, + 758, + 467, + 773 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nz = E _ {\\theta} \\left(F _ {\\theta [ 1: ]} (f), H _ {\\theta} (f)\\right) \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 204, + 777, + 467, + 792 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {t} ^ {\\mathrm {c l s}} (x, y) = \\mathcal {L} _ {\\mathrm {c e}} \\left(G _ {\\phi} (z), y\\right), \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 147, + 796, + 467, + 813 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathrm{mask}(x,r)$ denotes applying random masking with ratio $r$ on image $x$ , $f$ is the embedding extracted by the first encoder block, which is the input to the two branches of our Bilateral MAE, and $G_{\\phi}(z)$ is the estimated class distribution used for in the cross entropy loss.", + "bbox": [ + 75, + 825, + 468, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Image fusion with detailed loss. For the detailed head and corresponding loss, we discovered that working in the frequency domain makes it easier for the network to attend to high-frequency details, which is exactly what the detailed branch should reconstruct. We define a frequency-masking function $M(\\cdot)$ that converts its argument (an image patch) to the frequency domain, then masks out low frequencies using a circular mask around the origin. As shown in Fig. 2, the MAE decoder is shared by the two branches of our model since they have similar reconstruction tasks, as well as input and output shapes. Let $D_{\\theta}$ be this shared decoder, then the image-level outputs of the two branches and the reconstruction loss $\\mathcal{L}_t^{\\mathrm{rec}}$ are:", + "bbox": [ + 496, + 90, + 890, + 287 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nf = F _ {\\theta [: 1 ]} (\\operatorname {m a s k} (x, r)) \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 602, + 300, + 890, + 316 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nx ^ {\\prime} = D _ {\\theta} \\left(F _ {\\theta [ 1: ]} (f)\\right) \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 598, + 319, + 890, + 335 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nx ^ {\\prime \\prime} = \\text {i f t 2} \\left(M \\left(D _ {\\theta} \\left(H _ {\\theta} (f)\\right)\\right)\\right) \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 594, + 337, + 890, + 354 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {x} = x ^ {\\prime} + x ^ {\\prime \\prime} \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 602, + 356, + 890, + 372 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {t} ^ {\\text {r e c}} = \\mathcal {L} _ {\\text {m s e}} (x, \\hat {x}), \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 584, + 375, + 890, + 392 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $x'$ and $x''$ are the main and residual detailed outputs, respectively, and ifft2 is the inverse Fast Fourier Transform.", + "bbox": [ + 500, + 402, + 890, + 434 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The detailed loss $\\mathcal{L}_t^{\\mathrm{det}}$ also makes use of the frequencymasking function $M$ to compare the output of the detailed branch and the difference between two MAE reconstructions of the input image:", + "bbox": [ + 496, + 434, + 890, + 494 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {x} _ {1} = D _ {\\theta} \\left(F _ {\\theta} \\left(\\operatorname {m a s k} \\left(x, r _ {1}\\right)\\right)\\right) \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 550, + 508, + 890, + 523 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {x} _ {2} = D _ {\\theta} \\left(F _ {\\theta} (\\operatorname {m a s k} (x, r _ {2}))\\right) \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 550, + 527, + 890, + 542 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {t} ^ {\\mathrm {d e t}} = | | M \\left(D _ {\\theta} \\left(H _ {\\theta} (f)\\right) - M \\left(\\hat {x} _ {2} - \\hat {x} _ {1}\\right) \\right| | _ {1}, \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 537, + 544, + 890, + 561 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\hat{x}_1$ and $\\hat{x}_2$ are two reconstructed images (detached from the gradient computation graph) using different masking ratios $r_1$ and $r_2$ , respectively. The residual difference $\\hat{x}_2 - \\hat{x}_1$ is used as supervision in the frequency domain for the detailed branch in loss $\\mathcal{L}_t^{\\mathrm{det}}$ . An illustration can be found in Fig. 3.", + "bbox": [ + 496, + 574, + 890, + 662 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "A weighted sum of classification loss $\\mathcal{L}_t^{\\mathrm{cls}}$ , reconstruction loss $\\mathcal{L}_t^{\\mathrm{rec}}$ , and detail loss $\\mathcal{L}_t^{\\mathrm{det}}$ is used as the overall loss for training:", + "bbox": [ + 496, + 664, + 890, + 710 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {t} = \\lambda_ {\\mathrm {c l s}} \\mathcal {L} _ {t} ^ {\\mathrm {c l s}} + \\lambda_ {\\mathrm {r e c}} \\mathcal {L} _ {t} ^ {\\mathrm {r e c}} + \\lambda_ {\\mathrm {d e t}} \\mathcal {L} _ {t} ^ {\\mathrm {d e t}}. \\tag {12}\n$$\n", + "text_format": "latex", + "bbox": [ + 560, + 722, + 890, + 739 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Pseudocode for our method is given in Algorithm 1.", + "bbox": [ + 500, + 751, + 841, + 767 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. Experimental Results", + "text_level": 1, + "bbox": [ + 500, + 781, + 704, + 797 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Benchmarks and Implementation", + "text_level": 1, + "bbox": [ + 500, + 806, + 792, + 821 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Datasets and settings. We experiment on three datasets: CIFAR-100 [16], ImageNet-Subset, and ImageNet-Full [6] to evaluate the performance of our approach. For CIFAR-100 and ImageNet-Subset, we test on 10-, 20- and 50-task scenarios, all with equal numbers of classes per task. We", + "bbox": [ + 496, + 824, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "19107", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/bcf872f93dee9c777892de3c804c9e49d4c2abab9dd7f64153954d0526cc9dfa.jpg", + "image_caption": [ + "Figure 4. Performance evolution over incremental tasks on CIFAR-100 on 10-, 20- and 50-task scenarios." + ], + "image_footnote": [], + "bbox": [ + 163, + 99, + 372, + 263 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/8fe608cc81c9ed84b0c7530029041ac67aafb95127a0752dbf0ba1a914d2e830.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 377, + 99, + 586, + 263 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/a1b493e45cafadc068437d8be0b74033bb4b91d9e0328768730939e0564160e9.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 591, + 99, + 800, + 263 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/97dd708fbab58bfb739ab602a430aa39b24f94592bf317399c340184a526d54d.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodN=10N=20N=50
Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓
iCaRL [29]65.2750.7431.2361.2043.7532.4056.0836.6236.59
UCIR [12]58.6643.3935.6758.1740.6337.7556.8637.0938.13
BiC [36]68.8053.5428.4466.4847.0229.3062.0941.0434.27
PODNet [8]58.0341.0541.4753.9735.0236.7051.1932.9940.42
DER w/o P [40]75.3665.2215.0274.0962.4823.5572.4159.0826.73
DER [40]74.6464.3515.7873.9862.5523.4772.0559.7626.59
DyTox [9]75.4762.1015.4375.1059.4121.6073.8957.2124.22
Ours79.1268.4012.1778.7665.2214.3976.9563.1218.34
", + "bbox": [ + 205, + 291, + 764, + 445 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Table 1. Results on CIFAR-100 in average accuracy (%), last phase accuracy (%), and forgetting F (% on 10-, 20- and 50-task scenarios.", + "bbox": [ + 76, + 446, + 885, + 460 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "evaluate the 10-task setting for ImageNet-Full in which 100 new classes are included in each task. To measure the overall accuracy after all tasks during training, we report the average accuracy of learned tasks after each task and the accuracy of all tasks at the end of incremental learning.", + "bbox": [ + 75, + 484, + 468, + 561 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Implementation details. We use the same network for all datasets. Models are trained from scratch to prevent data leakage with batch size of 1024 using Adam [14] with initial learning rate 1e-4 and cosine decay. The loss weights from Eq. 12 are set to $\\lambda_{cls} = 0.01$ , $\\lambda_{rec} = 1.0$ and $\\lambda_{det} = 1.0$ . The masking ratios are set to $r = 0.75$ , $r_1 = 0.75$ , and $r_2 = 0.4$ . Each task is trained for 400 epochs. For exemplar-based methods from the literature, we store 20 samples for each classes (as is common practice).", + "bbox": [ + 75, + 582, + 468, + 717 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We use 5 transformer blocks for the encoder and 1 for the decoder. All transformer blocks have an embedding dimension of 384 and 12 self-attention heads. This design differs from the original MAE as it is much more lightweight. We save image patches occupying the same amount of memory as other methods which store 20 full images per class. For example, we select 80 images and randomly save only $25\\%$ patches from each using a masking ratio of 0.75 (thus only occupying the same space as 20 whole images). The detailed block is implemented with a 3-layer MLP keeping the dimension at 384. Further details about network architecture are given in the Supplementary Material.", + "bbox": [ + 75, + 719, + 470, + 901 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Comparison with the state-of-the-art", + "text_level": 1, + "bbox": [ + 500, + 484, + 818, + 501 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In this section we compare our approach with the state-of-the-art, including DER [40] and DyTox [9]. In all plots and tables, \"DER w/o P\" denotes DER [40] without pruning, therefore leading to more parameters being added across tasks. DyTox [9] also uses a transformer architecture and we use the official codebase to reproduce its results.", + "bbox": [ + 496, + 508, + 890, + 599 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "CIFAR-100. We report results in average accuracy (Avg), the accuracy after the last task (Last), and average forgetting (F) in Table 1. It is clear that under each setting our method outperforms others by a large margin. For longer task sequences, our bilateral MAE benefits from self-supervised reconstruction and richer replay data and it forgets much less compared to other methods. An overall accuracy curve is given in Fig. 4. Using the same amount of replay storage, our method outperforms DyTox by about $6\\%$ in accuracy after the last task in all three scenarios.", + "bbox": [ + 496, + 613, + 892, + 763 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "ImageNet-Subset and ImageNet-Full. We report performance on ImageNet-Subset and ImageNet-Full in Tables 2 and 3, respectively. Our method outperforms DyTox [9] by $1.19\\%$ , $2.53\\%$ , and $2.85\\%$ absolute gain in accuracy after the last task on the 10-, 20- and 50-task settings, respectively. The higher average accuracy during each phase and lower forgetting also demonstrates the effectiveness of our method in alleviating forgetting. We also", + "bbox": [ + 496, + 779, + 893, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "19108", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/8c43506805450191905fa3f0de49425a1f2d646825d336d0ea5cf76bf90a5a60.jpg", + "image_caption": [ + "Figure 5. Performance evolution over incremental tasks on ImageNet-Subset." + ], + "image_footnote": [], + "bbox": [ + 155, + 99, + 369, + 268 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/237955116686f7b99a4bc37a0236ed4dd601132ccdfd27eb2002c69f86f616ec.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 372, + 99, + 588, + 268 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/a5efb5db626293b21b504615bccc1b091c4166aabd8dd45d6325c4132ab96a7f.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 594, + 101, + 807, + 268 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/b71d7ed80e1c09be6941f3f0720556b65dea8f83bd2862ffa47e3d69f7921548.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodN=10N=20N=50
Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓
BiC [36]64.9655.0731.3259.4049.3534.7053.7544.5640.23
PODNet [8]63.4451.7535.6355.1145.3741.7051.7242.9444.65
DER w/o P [40]77.1866.7014.8672.7061.7420.7670.4458.8724.20
DER [40]76.1266.0615.0972.5661.5120.4669.7758.1925.35
DyTox [9]77.1569.1014.6673.1361.8717.3271.5160.0220.54
Ours79.5470.2912.0475.2064.4014.8974.4262.8717.22
", + "bbox": [ + 205, + 295, + 764, + 419 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/3eb2a878048386286fb3a30bd931b781a5e402e2a2d53247a0a1aa9cad4e09ab.jpg", + "table_caption": [ + "Table 2. Results on ImageNet-Subset in average and last phase accuracy (%) and forgetting rate F (%) on 10-, 20- and 50-task scenarios." + ], + "table_footnote": [], + "table_body": "
Methodtop-1top-5
Avg ↑Last ↑Avg ↑Last ↑
iCaRL [29]38.4022.7063.7044.00
Simple-DER66.6359.2485.6280.76
DER w/o P [40]68.8460.1688.1782.86
DER [40]66.7358.6287.0881.89
DyTox [9]71.2963.3488.5984.49
Ours74.7666.1591.4387.13
", + "bbox": [ + 117, + 455, + 429, + 579 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "illustrate the performance evolution on ImageNet-Subset in Fig. 5. Our method has accuracy similar to DyTox in the first task, but in later tasks our method surpasses all others, especially for long task sequences. On the larger-scale ImageNet-Full, our Bilateral MAE significantly outperforms other methods by about $3\\%$ in all metrics.", + "bbox": [ + 75, + 623, + 468, + 715 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 729, + 230, + 744 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Ablations on different components. Our bilateral MAE consists of a self-supervised reconstruction task, generated data for replay, and a bilateral MAE branch for image- and embedding-level fusion. We ablate on these three factors in Table 4. These three major components in our method have different functions and they cooperate to boost performance compared with the baseline by about $6\\%$ . We observe that: (a) More high-quality replay data has a direct contribution to the performance and masking ration of $r = 0.75$ masking ratio yields $4 \\times$ replay for the same storage cost as the", + "bbox": [ + 75, + 750, + 470, + 901 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/6dd805524ab7c25061e80b3b3d74768e36ec6a332975f6690384c4d2d0d418c0.jpg", + "table_caption": [ + "Table 3. Results on ImageNet-Full for 10 incremental tasks." + ], + "table_footnote": [], + "table_body": "
MethodReplayReconstructionBilateralAvgLast
Baseline73.4062.31
Variants✓75.8864.35
✓✓77.4866.54
✓✓✓79.1268.40
", + "bbox": [ + 506, + 455, + 885, + 549 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/6aeffb04331f87e48c30f54bdb89c5b2ce55ac757b20059370c5e1166f668443.jpg", + "table_caption": [ + "Table 4. Ablative experiments on each component of our proposed method in the 10-task setting on CIFAR-100. Replay denotes using generated data from MAE for replay, Reconstruction means applying the self-supervised reconstruction loss, and Bilateral indicates introduction the detailed branch of the MAE." + ], + "table_footnote": [], + "table_body": "
rData SourceAvgLast
0.60Generated77.5067.37
0.75Generated79.1268.40
0.90Generated77.1267.02
N/AReal79.5768.87
", + "bbox": [ + 588, + 633, + 805, + 726 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 5. Ablation on the masking ratio and quality of generated data. Experiments are on CIFAR-100 in the 10-task setting and we report top-1 accuracy in %. Data Source indicates whether replay is generated or real. In the last row we replay a selection of of real images equivalent in storage size to using $r_1 = 0.75$ .", + "bbox": [ + 496, + 726, + 893, + 796 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "baseline. (b) The reconstruction loss serves as effective self-supervision and improves performance by about $2\\%$ in average accuracy. (c) The bilateral architecture works well by improving replay data generation quality and introducing image and embedding-level supervision.", + "bbox": [ + 496, + 825, + 893, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "19109", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/2bb1820b88ec807e3e807bf1627b6c4ae8f4e04eeffe944a541eb928c2bf69b5.jpg", + "table_caption": [], + "table_footnote": [ + "Table 6. Ablative experiments on the detailed head. Experiments are on CIFAR-100 in the 10-task setting and we report the top-1 accuracy in $\\%$ . Domain denotes to which domain our loss is applied." + ], + "table_body": "
DomainAvgLast
Spatial77.4565.93
Frequency79.1268.40
", + "bbox": [ + 189, + 88, + 356, + 143 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/fb7984d0f1b1d796a542cf6f2a72e951542fbace7c680a45ba54885eaa46427f.jpg", + "image_caption": [ + "Figure 6. Ablation on masking ratio $r_2$ in $\\mathcal{L}_t^{\\mathrm{det}}$ . The other masking ratio $r_1$ is set to $75\\%$ as the reference." + ], + "image_footnote": [], + "bbox": [ + 127, + 229, + 401, + 393 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Masking ratio. A key parameter of MAE [11] is the masking ratio $r$ . There is trade-off on $r$ : too large $r$ (e.g. 0.95) leads to poor reconstruction, which influences the quality of replay data and causes more serious forgetting. However, too small $r$ yields a limited extra amount of replay data (e.g. we can afford only about $11\\%$ extra replay data when $r$ is 0.10). The results in Table 5 show that $r = 0.75$ is a good trade-off for our bilateral MAE. To verify the quality of generated data for replay, also include results using original images for replay in place of generated ones. Results in rows 2 and 4 of Table 5 show that our method achieves good quality images with less than $0.5\\%$ accuracy difference compared to replaying real images.", + "bbox": [ + 75, + 448, + 470, + 645 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Frequency domain for the detailed loss. We implemented the detailed loss by converting embeddings from the spatial domain to the frequency domain. This aims to allow concentration on high-frequency information which matches the learning objective of the detailed MAE branch. As shown in Table 6, it is beneficial to make this conversion as it leads to a more than $2\\%$ gain at the last task.", + "bbox": [ + 75, + 659, + 468, + 765 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Ablation on $r_1$ and $r_2$ in the detailed loss. We set $r_1$ to 0.75 for all these experiments as a reference and we vary $r_2$ used for computing the ground truth of the detailed loss. The trade-off on $r_2$ is that large $r_2$ results in small differences between the reconstructed results from mask ratios $r_1$ and $r_2$ and therefore there is little information in the supervisory signal for the detailed loss and the impact of the detailed branch is reduced. On the other hand, too small", + "bbox": [ + 75, + 780, + 470, + 900 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/09e5ab1272eda62ae6a272a4d6f309c8dd7fe26e67dccc97a90a9b01de78bd9a.jpg", + "table_caption": [], + "table_footnote": [ + "Table 7. Comparison of model sizes. We compare two versions of our Bilateral MAE and competing models. Experiments were conducted on CIFAR-100 with 10 tasks." + ], + "table_body": "
MethodParameters (M)Avg ↑Last ↑F ↓
DER w/o P112.2775.3665.2215.02
DyTox10.7375.4762.1015.43
Ours (MLP size = 1536)12.8979.1268.4012.17
Ours (MLP size = 768)9.3578.3667.5212.90
", + "bbox": [ + 500, + 88, + 890, + 167 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "$r_2$ (e.g. 0.10) maintains most of the residual part of reconstructed images from the main branch, which may bring weak supervision for the main branch and slow its training. We show results for a range of $r_2$ values in Fig. 6. These results show that an $r_2$ of about 0.40 is good for providing supervision to the detailed branch of our MAE.", + "bbox": [ + 498, + 226, + 890, + 316 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Model and exemplar sizes. To compare the effectiveness of different methods, normally models with the same or similar number of parameters are used with an equal number of exemplars. In our approach, we adapt the original MAE to be more lightweight and the number of parameters is comparable to or even smaller than DyTox, as shown in Table 7 (last row). We set the masking ratio to $75\\%$ by default and save 80 exemplars per class, and therefore the storage size for both models and exemplars is similar since our stored image patches require exactly the same as baselines using only 20 exemplars.", + "bbox": [ + 496, + 340, + 890, + 507 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Ablation on effective buffer size. In Table 8 we compare our method with Dytox using the same buffer size by masking input image patches in input to DyTox. All three rows use the same memory size for storing exemplars. Using 80 exemplars with masking ratio of $75\\%$ , DyTox (last row) achieves better performance than when using 20 full-image exemplars. It still performs worse than our approach, which shows that our performance gain does not simply come from the additional exemplars, but also from the integration of the MAE into our bilateral architecture with the Detailed Branch.", + "bbox": [ + 496, + 530, + 890, + 696 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Reconstruction analysis. We illustrate results of image reconstruction in the 10-task setting on ImageNet-Subset in Fig. 7. Randomly selected images from tasks 1, 4, 7, and 10 are shown in the left column. Our bilateral MAE learns to reconstruct images in a task-agnostic way, which helps generate reasonable results for future tasks even before learning them. The detailed branch of our MAE learns to reconstruct high-frequency details complementary to the main branch. The results from the main branch sometimes lack sample-specific characteristics, but with the help of our proposed detailed branch the reconstructions are more accurate and provide better generated replay data.", + "bbox": [ + 496, + 720, + 890, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "19110", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/f675e55d9fe3a6e651045cf1210cdb24658bd690f4ef0c02952566650db44d49.jpg", + "image_caption": [ + "Image" + ], + "image_footnote": [], + "bbox": [ + 81, + 85, + 153, + 258 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/65f60aeb255c7e0db0f32b7cef9073a7973463390543321387062664a20b02ae.jpg", + "image_caption": [ + "Task 1" + ], + "image_footnote": [], + "bbox": [ + 171, + 88, + 336, + 260 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/193eca8f004189599fb6abbb5a0f02d15a3b91d93cdc5026f096319542fb6f8e.jpg", + "image_caption": [ + "Task 4", + "Figure 7. Reconstructed images from ImageNet-Subset in the 10-task setting. Four original images were selected from tasks 1, 4, 6, and 10 and are shown on the left. In the remaining columns we show reconstructed images using our combined Bilateral MAE (left), only the detailed branch of our MAE (middle), and only the main branch of our MAE (right)." + ], + "image_footnote": [], + "bbox": [ + 354, + 88, + 519, + 260 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/1f6ca61ea5470c0ed2b64db7413117da6ad32c2b92733cbe375b5e03332f9574.jpg", + "image_caption": [ + "Task 7" + ], + "image_footnote": [], + "bbox": [ + 537, + 88, + 702, + 260 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/4f90a44ff2b2e59a0a65e4282a3f2fcc955b971c9f8c02588fda54fde540918d.jpg", + "image_caption": [ + "Task 10" + ], + "image_footnote": [], + "bbox": [ + 720, + 88, + 885, + 260 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/ff3b038305248ba574efeaee4e1edb6bb142bd3137cdaeadf58628c20bbe0a82.jpg", + "table_caption": [], + "table_footnote": [ + "Table 8. Ablation on effective buffer size with equal memory usage. Dytox† represents applying a mask ratio $r = 75\\%$ directly to stored image exemplars in order to have the same number of exemplars and storage size for DyTox as in our setting." + ], + "table_body": "
MethodBufferMemory size25% PatchesImagesAcc(%)
Ours801x✓68.40
DyTox201x✓62.10
DyToxt801x✓65.46
", + "bbox": [ + 78, + 335, + 468, + 398 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/ed239fd20b7b53c839b8407fbdc3c4616a1fcfa81bd80bcbe5c1d4637aa71df5.jpg", + "image_caption": [ + "Figure 8. Comparison of feature space density $\\pi$ ." + ], + "image_footnote": [], + "bbox": [ + 81, + 463, + 465, + 638 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "More generalizable representations help CIL. We calculated the feature space density metric [32] for different methods following PASS [46]: $\\pi = \\pi_{intra} / \\pi_{inter}$ , where $\\pi_{intra}$ denotes the average cosine similarity within the same class and $\\pi_{inter}$ denotes the one within different classes. Increased feature space density is associated with stronger generalization under data shift [46]. We then compared feature space density after training all tasks, as shown in Figure 8 above. It is clear that Ours yields significantly higher density than other methods.", + "bbox": [ + 75, + 671, + 468, + 824 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Ablation with other efficient replay methods. We compared the replay samples generated by MAE in our framework with a variety of memory-efficient methods based on latent replay [19], synthesized exemplars [20], down-", + "bbox": [ + 75, + 839, + 470, + 902 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/4af50a43e2986b6e720e59f853c6c6efe1aff3f34b29046ed14ee2fc54cb863e.jpg", + "table_caption": [], + "table_footnote": [ + "Table 9. Comparison of our bilateral MAE framework with other memory-efficient methods on the CIFAR-100 10-task setting. Memory indicates the required storage space per class (in KB)." + ], + "table_body": "
MetricMemoryAvg↑Last↑
Latent replay (CVPRW'20) [19]-62.4451.30
MCIL (CVPR'20) [20]6063.2553.12
Down-scaled (TNNLS'21) [45]6067.0455.40
JPEG compression (ICLR'22) [34]6072.3461.32
CIM (CVPR'23) [22]6075.3063.05
Ours6079.1268.40
", + "bbox": [ + 504, + 335, + 888, + 448 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "scaling [45], JPEG image compression [34], and CIM [22] (foreground extraction and background compression). All these methods use the same amount of storage (except Latent Replay uses a GAN with 4.5M parameters), while our approach achieves consistently higher performance.", + "bbox": [ + 498, + 515, + 890, + 592 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusions", + "text_level": 1, + "bbox": [ + 500, + 619, + 627, + 633 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this work, we demonstrate that Masked Autoencoders are efficient incremental learners. Our approach stores random image patches as exemplars and it can reconstruct high-quality images from only partial information for replay. Furthermore, we propose a novel bilateral MAE architecture which further improves embedding diversity and reconstruction quality. Our Bilateral MAE approach significantly outperforms previous state-of-the-art methods for the same exemplar storage cost.", + "bbox": [ + 496, + 648, + 890, + 787 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgements This work is funded by NSFC (NO. 62225604, 62206135), and the Fundamental Research Funds for the Central Universities (Nankai University, 070-63233085). Computation is supported by the Supercomputing Center of Nankai University.", + "bbox": [ + 496, + 824, + 890, + 902 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "19111", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Rahaf Aljundi, Punarjay Chakravarty, and Tinne Tuytelaars. Expert gate: Lifelong learning with a network of experts. In IEEE Conf. Comput. Vis. Pattern Recog., 2017. 1", + "[2] Eden Belouadah, Adrian Popescu, and Ioannis Kanellos. A comprehensive study of class incremental learning algorithms for visual tasks. Neural Networks, 135:38-54, 2021. 1, 2", + "[3] Arslan Chaudhry, Marc'Aurelio Ranzato, Marcus Rohrbach, and Mohamed Elhoseiny. Efficient lifelong learning with a gem. In Int. Conf. Learn. Represent., 2019. 2", + "[4] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning of visual representations. In International conference on machine learning, pages 1597-1607. PMLR, 2020. 2", + "[5] Matthias Delange, Rahaf Aljundi, Marc Masana, Sarah Parisot, Xu Jia, Ales Leonardis, Greg Slabaugh, and Tinne Tuytelaars. A continual learning survey: Defying forgetting in classification tasks. TPAMI, 2021. 1, 2", + "[6] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In IEEE Conf. Comput. Vis. Pattern Recog., 2009. 4", + "[7] Carl Doersch, Abhinav Gupta, and Alexei A Efros. Unsupervised visual representation learning by context prediction. In Int. Conf. Comput. Vis., 2015. 2", + "[8] Arthur Douillard, Matthieu Cord, Charles Ollion, Thomas Robert, and Eduardo Valle. Podnet: Pooled outputs distillation for small-tasks incremental learning. In Eur. Conf. Comput. Vis., 2020. 2, 5, 6", + "[9] Arthur Douillard, Alexandre Rame, Guillaume Couairon, and Matthieu Cord. Dytox: Transformers for continual learning with dynamic token expansion. In IEEE Conf. Comput. Vis. Pattern Recog., 2022. 5, 6", + "[10] Spyros Gidaris, Praveer Singh, and Nikos Komodakis. Unsupervised representation learning by predicting image rotations. In Int. Conf. Learn. Represent., 2018. 2", + "[11] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In IEEE Conf. Comput. Vis. Pattern Recog., 2022. 1, 2, 7", + "[12] Saihui Hou, Xinyu Pan, Chen Change Loy, Zilei Wang, and Dahua Lin. Learning a unified classifier incrementally via rebalancing. In IEEE Conf. Comput. Vis. Pattern Recog., 2019. 5", + "[13] David Isele and Akansel Cosgun. Selective experience replay for lifelong learning. In AAAI, 2018. 1", + "[14] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. In Int. Conf. Learn. Represent., 2015. 5", + "[15] James Kirkpatrick, Razvan Pascanu, Neil Rabinowitz, Joel Veness, Guillaume Desjardins, Andrei A Rusu, Kieran Milan, John Quan, Tiago Ramalho, Agnieszka Grabska-Barwinska, et al. Overcoming catastrophic forgetting in neural networks. Proceedings of the national academy of sciences, 2017. 1, 2" + ], + "bbox": [ + 78, + 114, + 467, + 898 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[16] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images, 2009. 4", + "[17] Zhizhong Li and Derek Hoiem. Learning without forgetting. In Eur. Conf. Comput. Vis., 2016. 1, 2", + "[18] Feng Liang, Yangguang Li, and Diana Marculescu. Supmae: Supervised masked autoencoders are efficient vision learners. arXiv preprint arXiv:2205.14540, 2022. 2", + "[19] Xialei Liu, Chenshen Wu, Mikel Menta, Luis Herranz, Bogdan Raducanu, Andrew D Bagdanov, Shangling Jui, and Joost van de Weijer. Generative feature replay for class incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog. Worksh., 2020. 8", + "[20] Yaoyao Liu, Yuting Su, An-An Liu, Bernt Schiele, and Qianru Sun. Mnemonics training: Multi-class incremental learning without forgetting. In IEEE Conf. Comput. Vis. Pattern Recog., pages 12245-12254, 2020. 8", + "[21] David Lopez-Paz and Marc'Aurelio Ranzato. Gradient episodic memory for continual learning. Adv. Neural Inform. Process. Syst., 2017. 2", + "[22] Zilin Luo, Yaoyao Liu, Bernt Schiele, and Qianru Sun. Class-incremental exemplar compression for class-incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., pages 11371-11380, 2023. 8", + "[23] Arun Mallya, Dillon Davis, and Svetlana Lazebnik. Piggyback: Adapting a single network to multiple tasks by learning to mask weights. In Eur. Conf. Comput. Vis., 2018. 1", + "[24] Arun Mallya and Svetlana Lazebnik. Packnet: Adding multiple tasks to a single network by iterative pruning. In IEEE Conf. Comput. Vis. Pattern Recog., 2018. 1, 2", + "[25] Marc Masana, Xialei Liu, Barttomiej Twardowski, Mikel Menta, Andrew D. Bagdanov, and Joost van de Weijer. Class-incremental learning: Survey and performance evaluation on image classification. IEEE Trans. Pattern Anal. Mach. Intell., 2022. 1", + "[26] Michael McCloskey and Neal J Cohen. Catastrophic interference in connectionist networks: The sequential learning problem. In *Psychology of learning and motivation*. Elsevier, 1989. 1", + "[27] Mehdi Noroozi and Paolo Favaro. Unsupervised learning of visual representations by solving jigsaw puzzles. In Eur. Conf. Comput. Vis., 2016. 2", + "[28] Quang Pham, Chenghao Liu, and Steven Hoi. Dualnet: Continual learning, fast and slow. Adv. Neural Inform. Process. Syst., 2021. 2", + "[29] Sylvestre-Alvise Rebuffi, Alexander Kolesnikov, Georg Sperl, and Christoph H Lampert. icarl: Incremental classifier and representation learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2017. 1, 2, 5, 6", + "[30] Matthew Riemer, Ignacio Cases, Robert Ajemian, Miao Liu, Irina Rish, Yuhai Tu, and Gerald Tesauro. Learning to learn without forgetting by maximizing transfer and minimizing interference. In Int. Conf. Learn. Represent., 2019. 2", + "[31] David Rolnick, Arun Ahuja, Jonathan Schwarz, Timothy Lillicrap, and Gregory Wayne. Experience replay for continual learning. Adv. Neural Inform. Process. Syst., 2019. 1", + "[32] Karsten Roth, Timo Milbich, Samarth Sinha, Prateek Gupta, Bjorn Ommer, and Joseph Paul Cohen. Revisiting training strategies and generalization performance in deep metric" + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "19112", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "learning. In Int. Mach. Learn., pages 8242-8252. PMLR, 2020. 8", + "[33] James Smith, Yen-Chang Hsu, Jonathan Balloch, Yilin Shen, Hongxia Jin, and Zsolt Kira. Always be dreaming: A new approach for data-free class-incremental learning. In Int. Conf. Comput. Vis., 2021. 2", + "[34] Liyuan Wang, Xingxing Zhang, Kuo Yang, Longhui Yu, Chongxuan Li, Lanqing Hong, Shifeng Zhang, Zhenguo Li, Yi Zhong, and Jun Zhu. Memory replay with data compression for continual learning. In Int. Conf. Learn. Represent., 2022. 8", + "[35] Chenshen Wu, Luis Herranz, Xialei Liu, Joost van de Weijer, Bogdan Raducanu, et al. Memory replay gans: Learning to generate new categories without forgetting. Adv. Neural Inform. Process. Syst., 2018. 1, 2", + "[36] Yue Wu, Yinpeng Chen, Lijuan Wang, Yuancheng Ye, Zicheng Liu, Yandong Guo, and Yun Fu. Large scale incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2019. 2, 5, 6", + "[37] Zhirong Wu, Yuanjun Xiong, Stella X Yu, and Dahua Lin. Unsupervised feature learning via non-parametric instance discrimination. In IEEE Conf. Comput. Vis. Pattern Recog., 2018. 2", + "[38] Ye Xiang, Ying Fu, Pan Ji, and Hua Huang. Incremental learning using conditional adversarial networks. In Int. Conf. Comput. Vis., 2019. 1", + "[39] Ju Xu and Zhanxing Zhu. Reinforced continual learning. Adv. Neural Inform. Process. Syst., 2018. 2", + "[40] Shipeng Yan, Jiangwei Xie, and Xuming He. Der: Dynamically expandable representation for class incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2021. 5, 6", + "[41] Hongxu Yin, Pavlo Molchanov, Jose M Alvarez, Zhizhong Li, Arun Mallya, Derek Hoiem, Niraj K Jha, and Jan Kautz. Dreaming to distill: Data-free knowledge transfer via deep-inversion. In IEEE Conf. Comput. Vis. Pattern Recog., 2020. 2", + "[42] Jure Zbontar, Li Jing, Ishan Misra, Yann LeCun, and Stéphane Deny. Barlow twins: Self-supervised learning via redundancy reduction. In International Conference on Machine Learning, pages 12310-12320. PMLR, 2021. 2", + "[43] Mengyao Zhai, Lei Chen, Frederick Tung, Jiawei He, Megha Nawhal, and Greg Mori. Lifelong gan: Continual learning for conditional image generation. In Int. Conf. Comput. Vis., 2019. 1", + "[44] Junting Zhang, Jie Zhang, Shalini Ghosh, Dawei Li, Serafettin Tasci, Larry Heck, Heming Zhang, and C-C Jay Kuo. Class-incremental learning via deep model consolidation. In WACV, 2020. 2", + "[45] Hanbin Zhao, Hui Wang, Yongjian Fu, Fei Wu, and Xi Li. Memory-efficient class-incremental learning for image classification. TNNLS, 33(10):5966-5977, 2021. 8", + "[46] Fei Zhu, Xu-Yao Zhang, Chuang Wang, Fei Yin, and ChengLin Liu. Prototype augmentation and self-supervision for incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2021. 2, 8" + ], + "bbox": [ + 78, + 90, + 468, + 883 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "19113", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/Masked Autoencoders are Efficient Class Incremental Learners/3431d5c0-b1b6-47da-9e6e-bca6fba5a382_model.json b/2023/Masked Autoencoders are Efficient Class Incremental Learners/3431d5c0-b1b6-47da-9e6e-bca6fba5a382_model.json new file mode 100644 index 0000000000000000000000000000000000000000..a06e751945ac89d258a5970f68ba42125b7a6009 --- /dev/null +++ b/2023/Masked Autoencoders are Efficient Class Incremental Learners/3431d5c0-b1b6-47da-9e6e-bca6fba5a382_model.json @@ -0,0 +1,2343 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.165, + 0.131, + 0.806, + 0.151 + ], + "angle": 0, + "content": "Masked Autoencoders are Efficient Class Incremental Learners" + }, + { + "type": "text", + "bbox": [ + 0.117, + 0.18, + 0.851, + 0.218 + ], + "angle": 0, + "content": "Jiang-Tian Zhai \\(^{1}\\) Xialei Liu \\(^{1,*}\\) Andrew D. Bagdanov \\(^{2}\\) Ke Li \\(^{3}\\) Ming-Ming Cheng \\(^{1}\\) VCIP, CS, Nankai University \\(^{2}\\) MICC, University of Florence \\(^{3}\\) Tencent Youtu Lab" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.252, + 0.314, + 0.267 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.283, + 0.474, + 0.541 + ], + "angle": 0, + "content": "Class Incremental Learning (CIL) aims to sequentially learn new classes while avoiding catastrophic forgetting of previous knowledge. We propose to use Masked Autoencoders (MAEs) as efficient learners for CIL. MAEs were originally designed to learn useful representations through reconstructive unsupervised learning, and they can be easily integrated with a supervised loss for classification. Moreover, MAEs can reliably reconstruct original input images from randomly selected patches, which we use to store exemplars from past tasks more efficiently for CIL. We also propose a bilateral MAE framework to learn from image-level and embedding-level fusion, which produces better-quality reconstructed images and more stable representations. Our experiments confirm that our approach performs better than the state-of-the-art on CIFAR-100, ImageNet-Subset, and ImageNet-Full. The code is available at https://github.com/scok30/MAE-CIL." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.582, + 0.21, + 0.599 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.608, + 0.47, + 0.744 + ], + "angle": 0, + "content": "Deep learning has had a broad and deep impact on most computer vision tasks over the last ten years. Given the way humans learn continually in their lifespan, it is natural to expect models also to be able to accumulate knowledge and build on past experiences to adapt to new tasks incrementally. The real world is very dynamic, leading to varying data distributions over time, while deep models tend to catastrophically forget old tasks when learning new ones [26]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.744, + 0.471, + 0.88 + ], + "angle": 0, + "content": "Class Incremental Learning (CIL) aims to learn new classification tasks sequentially while avoiding catastrophic forgetting [2, 25]. CIL approaches can be roughly divided into three categories [5], i.e., Rehearsal-based methods [13, 29, 31], Regularization-based methods [15, 17], and Architecture-based methods [1, 23, 24]. Among them, Rehearsal-based methods achieve state-of-the-art performance by storing exemplars from past tasks or generating synthetic samples for replay." + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.249, + 0.895, + 0.416 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.417, + 0.895, + 0.542 + ], + "angle": 0, + "content": "Figure 1. Our proposed bilateral MAE for efficient CIL. The Replay Buffer contains random patches selected from past task images, which is more efficient than storing whole images. Combining these with masked input data from the current task, the MAE simultaneously learns to classify and reconstruct images from the masked input. To further improve the reconstructed image quality and learned representations, embedding-level and image-level fusion is used to learn more stable representations and more detailed reconstructions for CIL." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.568, + 0.895, + 0.84 + ], + "angle": 0, + "content": "Normally, only a fixed size of memory is allowed during incremental learning. Therefore, it limits the stored exemplars from past tasks. Other works exploit generative networks [35, 38, 43] (e.g., GANs) to synthesize samples from old tasks for replay. Although they can generate replay data to mitigate forgetting, a typical drawback is the quality of generated images, and that forgetting can also happen in generative models. In this work, we introduce Masked Autoencoders (MAEs) [11] as a base model to replay. It allows efficient exemplar storage by only requiring a small subset of patches to reconstruct whole images. Therefore, we can store more exemplars with the same amount of limited memory as other exemplar-based approaches. Compared to previous generative methods, replay by MAE is more stable because it uses partial cues to infer global information, which is task-agnostic and suffers less forgetting across tasks. This relieves the unstable generation effect of GANs across tasks with stationary image patches." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Masked Autoencoders (MAEs) [11] were initially proposed to learn better feature representations in self-supervised learning scenarios. In this work, we see it as efficient incremental learners and propose a novel bilat" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.348, + 0.901 + ], + "angle": 0, + "content": "*Corresponding author (xialei@nankai.edu.cn)" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "19104" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.257 + ], + "angle": 0, + "content": "eral transformer architecture for efficient exemplar replay in CIL. Our main idea is simple: by randomly masking patches of input images and training models to reconstruct the masked pixels, MAEs can provide a new form of self-supervised representation learning for CIL and thus learn more generalizable representations essential for CIL. In addition, leveraging a supervised objective with classification labels benefits unsupervised MAE in training efficiency and model robustness [18]. Masked inputs can also serve as strong classification regularization by only providing a random subset of data." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.258, + 0.473, + 0.514 + ], + "angle": 0, + "content": "When learning new tasks, the MAE can coarsely reconstruct images from sparsely sampled patches from exemplars. This process enables the framework to generate reconstructed replay data, but two problems remain: (i) the generated images tend to have less detailed and less realistic textures, which reduces data diversity for replay; and (ii) on the embedding-level, the linear classifier lacks information from low-level features. Therefore, we introduce a bilateral MAE framework with image-level and embedding-level fusion for CIL (see Fig. 1 for a schematic overview). Fusing a complementary detailed and reconstructed image alleviates catastrophic forgetting by enriching the insufficient replay data with detailed, high-quality data distributions. Embedding-level fusion from the two branches also maintains stable and diverse embeddings, and our framework can thus achieve a better trade-off between plasticity and stability." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.515, + 0.47, + 0.545 + ], + "angle": 0, + "content": "The main contributions of our bilateral MAE framework are threefold:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.55, + 0.47, + 0.612 + ], + "angle": 0, + "content": "- We introduce an MAE framework for efficient incremental learning that incorporates benefits from both self-supervised reconstruction and data generation for replay." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.619, + 0.47, + 0.68 + ], + "angle": 0, + "content": "- To further boost the quality of reconstructed images and learning efficiency, we design a novel bilateral MAE with two complementary branches for better-reconstructed images and regularized representations." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.687, + 0.47, + 0.733 + ], + "angle": 0, + "content": "- Our approach achieves state-of-the-art performance under different CIL settings on CIFAR-100, ImageNet-Subset, and ImageNet-Full." + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.55, + 0.47, + 0.733 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.745, + 0.22, + 0.76 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Incremental learning. Various methods have been proposed for incremental learning in the past few years [2, 5]. Recent works can be coarsely grouped into three categories: replay-based, regularization-based, and parameter-isolation methods. Replay-based methods mitigate the task-recency bias by replaying training samples from previous tasks. In addition to replaying samples, BiC [36], PODNet [8], and iCaRL [29] apply a distillation loss to prevent forgetting and enhance model stability. GEM [21], AGEM [3]," + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.152 + ], + "angle": 0, + "content": "and MER [30] exploit past-task exemplars by modifying gradients on current training samples to match old samples. Rehearsal-based methods may cause models to overfit stored samples." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.152, + 0.892, + 0.243 + ], + "angle": 0, + "content": "Pseudo-replay methods reconstruct the old data for replay. MeRGANs [35] use conditional GANs to balance the generation of old and current samples. Besides, dreamingrelevant methods like DeepInversion [41] and AlwaysBeDreaming [33] exploit backward signals to generate images similar to the original datasets." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.243, + 0.892, + 0.364 + ], + "angle": 0, + "content": "Regularization-based approaches, such as LwF [17], EWC [15], and DMC [44], offer methods to learn better representations while leaving enough plasticity for adaptation to new tasks. Parameter-isolation methods [24,39] use models with different computational graphs for each task. With the help of growing models, new model branches mitigate catastrophic forgetting at the cost of more parameters and computational costs." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.379, + 0.892, + 0.515 + ], + "angle": 0, + "content": "Self-Supervised Learning. Self-supervised learning [7, 27, 37] has been shown to help models learn generalizable features, which makes it natural to consider its application to incremental learning. Early works used pretext tasks like patch permutation [27] or rotation prediction [10]. Contrastive learning approaches model the pairwise similarity and dissimilarity between samples [4]. By comparison, MAEs [11] learn feature representations by reconstructing images from a masked version of inputs." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.515, + 0.892, + 0.651 + ], + "angle": 0, + "content": "There are a few works proposing self-supervision for class incremental learning. PASS [46] incorporates rotation prediction [10] to learn representations transferable across tasks. DualNet [28] uses Barlow Twins [42] to introduce a \"slow\" task that regularizes the \"fast\" incremental learning. In this paper, we explore the framework generates data for replay while applying semantic and detailed-level self-supervision, which mitigates forgetting via richer replay data and more generalizable features." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.665, + 0.729, + 0.681 + ], + "angle": 0, + "content": "3. Continual MAE for CIL" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.691, + 0.892, + 0.751 + ], + "angle": 0, + "content": "In this section, we first define the class incremental learning problem and the basic MAE model. Then we introduce our incremental learning framework and the bilateral MAE architecture it is based on." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.761, + 0.642, + 0.776 + ], + "angle": 0, + "content": "3.1. Preliminaries" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.892, + 0.901 + ], + "angle": 0, + "content": "The class incremental learning problem. CIL aims to sequentially learn tasks with new classes while preventing or alleviating forgetting of old tasks. At a specific phase of learning task \\( t \\in \\{1,2,\\dots,T\\} \\), model training can exploit only data from the current task \\( \\{(x_i^t,y_i^t)\\} \\), where \\( x_{i}^{t} \\) denotes image \\( i \\) in task \\( t \\) and \\( y_{i}^{t} \\) its corresponding class label. A CIL model typically consists of a feature extractor \\( F_{\\theta} \\) and a common classifier \\( G_{\\phi} \\) which grows at each new" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19105" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.09, + 0.891, + 0.317 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.319, + 0.893, + 0.361 + ], + "angle": 0, + "content": "Figure 2. Overall framework of our bilateral MAE for CIL. The masked input is passed through two branches with embedding-level fusion for classification and image-level fusion for reconstruction. Full images can be generated from a small sample of input patches and the reconstructed images can be used as replay." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.386, + 0.469, + 0.478 + ], + "angle": 0, + "content": "task. At task \\(t + 1\\), \\(C_{t + 1}\\) new classes are added to \\(G_{\\phi}\\). The feature extractor \\(F_{\\theta}\\) first maps the input \\(x\\) to a deep feature vector \\(z = F_{\\theta}(x)\\in \\mathbb{R}^{d}\\), where \\(d\\) is the dimension of the output feature representation, and then the unified classifier \\(G_{\\phi}(z)\\in \\mathbb{R}^{C_{1:t}}\\) produces a probability distribution over classes \\(C_{1:t}\\) which is used to make predictions on input \\(x\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.478, + 0.47, + 0.629 + ], + "angle": 0, + "content": "When training task \\( t \\), the model aims to minimize losses on the current task without degrading performance on previous tasks. A common technique for mitigating forgetting is to retain a small buffer of training samples from previous tasks. Let \\( \\epsilon \\) be this buffer of previous task samples. One essential problem for CIL is the limited amount of replay data. Compared to the full data of current task \\( t \\), only a few samples of old task classes are available (20 samples per class is a common setting), which causes imbalanced training between new and old tasks." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.644, + 0.469, + 0.856 + ], + "angle": 0, + "content": "An MAE framework for classification. An MAE first crops input image \\( x \\) into non-overlapping patches, and we denote the number of patches in the full image \\( x \\) as \\( N_{f} \\). After patchification, the MAE randomly masks a proportion \\( r \\in [0,1] \\) of the \\( N_{f} \\) patches, leaving only \\( N = \\lfloor N_{f} \\times (1 - r) \\rfloor \\) patches. Then these sampled \\( K \\times K \\) pixel patches are mapped to a visual embedding of dimension \\( D \\) using an MLP. After concatenating with a class token, the result is a tensor of size \\( \\mathbb{R}^{(N + 1) \\times D} \\). After positionally encoding the original patch locations, this input is passed to the MAE transformer encoder. This operation maintains the same shape of embedding. The output class token embedding can be used for classification with a cross-entropy loss \\( \\mathcal{L}_t^{\\mathrm{cls}} \\), as shown in Fig. 2." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.47, + 0.901 + ], + "angle": 0, + "content": "For the MAE Decoder, learnable mask tokens are inserted into the embeddings in place of the masked patches, and the shape of output from the MAE Encoder changes" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.385, + 0.892, + 0.569 + ], + "angle": 0, + "content": "from \\(\\mathbb{R}^{(N + 1)\\times D}\\) to \\(\\mathbb{R}^{(N_f + 1)\\times D}\\). Although the decoder is not used for classification, it helps the network backpropagate image-level reconstruction supervision to the embedding-level. This stabilizes the image embedding and helps the optimization process. Also, the reconstructed images after decoding provide richer, higher-quality replay data. To limit computation, we use a single-layer transformer block for the decoder. The additional classification loss after the encoder speeds up convergence and improves reconstruction efficiency during training. The mean squared error between the input image \\(x\\) and reconstructed image \\(\\hat{x}\\) is used as the reconstruction loss function \\(\\mathcal{L}_t^{\\mathrm{rec}}(x,\\hat{x})\\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.575, + 0.837, + 0.591 + ], + "angle": 0, + "content": "3.2. Efficient Exemplar Storage with MAEs" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.599, + 0.891, + 0.689 + ], + "angle": 0, + "content": "After training each task, we save small sample images and apply random masking. Keeping the same storage size can save more replay data per class since each sample occupies less space. For example, a masking ratio of 0.75 allows us to save \\(4 \\times\\) the number of (reconstructible) samples compared to conventional replay methods." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.689, + 0.892, + 0.84 + ], + "angle": 0, + "content": "Let \\( S \\) and \\( P \\) denote the size of the image and patch, respectively. Our encoder patchifies the input image into \\( \\frac{S}{P} \\times \\frac{S}{P} \\) patches. We save the 2D index \\( (i,j) \\) for each patch that is not masked. We need only one byte to save these indexes since their range is less than 255. The two additional bytes for saving this 2D index are negligible compared to the saved image patches. A masking ratio 0.75 on a \\( 224 \\times 224 \\) image requires only 36.75KB of storage. For \\( P = 16 \\), the number of saved patches is \\( (1 - 0.75) \\times (\\frac{224}{16})^2 = 49 \\), and the storage of indexes is only 98B." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.848, + 0.706, + 0.862 + ], + "angle": 0, + "content": "3.3. Bilateral MAE Fusion" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "To further boost reconstruction quality and embedding diversity, we propose a two-branches MAE to learn global" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19106" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.088, + 0.462, + 0.184 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.184, + 0.47, + 0.252 + ], + "angle": 0, + "content": "Figure 3. An example of extracting detailed images with reconstructed results from different masking ratios \\( r_1 \\) and \\( r_2 \\). The third image comes from the difference between the previous two, and the last image is the extracted high-frequency component from the third image." + }, + { + "type": "code_caption", + "bbox": [ + 0.079, + 0.268, + 0.395, + 0.282 + ], + "angle": 0, + "content": "Algorithm 1 Pseudocode of our Bilateral MAE." + }, + { + "type": "code", + "bbox": [ + 0.078, + 0.287, + 0.47, + 0.332 + ], + "angle": 0, + "content": "Input: The number of task \\(T\\), training samples \\(D_{t} = \\{(x_{i},y_{i})\\}_{t}\\) of task \\(t\\), model \\(\\Theta^0\\), replay buffer \\(\\epsilon\\), and masking ratios \\(r, r_1, r_2\\)." + }, + { + "type": "code_caption", + "bbox": [ + 0.079, + 0.333, + 0.214, + 0.347 + ], + "angle": 0, + "content": "Output: model \\(\\Theta^T\\)" + }, + { + "type": "code", + "bbox": [ + 0.088, + 0.348, + 0.262, + 0.362 + ], + "angle": 0, + "content": "1: for \\( t \\in \\{1, 2, \\dots, T\\} \\) do" + }, + { + "type": "code", + "bbox": [ + 0.089, + 0.363, + 0.212, + 0.376 + ], + "angle": 0, + "content": "2: \\(\\Theta^t\\gets \\Theta^{t - 1}\\)" + }, + { + "type": "code", + "bbox": [ + 0.089, + 0.379, + 0.378, + 0.393 + ], + "angle": 0, + "content": "3: \\(R_{t}\\gets \\mathrm{ReconstructOldSamples}(\\epsilon_{t},r)\\)" + }, + { + "type": "code", + "bbox": [ + 0.089, + 0.394, + 0.29, + 0.408 + ], + "angle": 0, + "content": "4: while not converged do" + }, + { + "type": "code", + "bbox": [ + 0.089, + 0.409, + 0.33, + 0.423 + ], + "angle": 0, + "content": "5: \\((x,y)\\gets\\) Sample \\((R_{t},D_{t})\\)" + }, + { + "type": "code", + "bbox": [ + 0.089, + 0.423, + 0.39, + 0.438 + ], + "angle": 0, + "content": "6: \\((\\mathcal{L}_t^{\\mathrm{cls}},\\mathcal{L}_t^{\\mathrm{rec}})\\gets\\) BilateralMAE \\((x,y)\\)" + }, + { + "type": "code", + "bbox": [ + 0.089, + 0.439, + 0.446, + 0.453 + ], + "angle": 0, + "content": "7: \\((\\hat{x}_1, \\hat{x}_2) \\gets \\text{MaskAndReconstruct}(x, r_1, r_2)\\)" + }, + { + "type": "code", + "bbox": [ + 0.089, + 0.454, + 0.4, + 0.469 + ], + "angle": 0, + "content": "8: \\(\\mathcal{L}_t^{\\mathrm{det}}\\gets\\) ComputeDetailLoss \\((\\hat{x}_1,\\hat{x}_2)\\)" + }, + { + "type": "code", + "bbox": [ + 0.089, + 0.469, + 0.414, + 0.484 + ], + "angle": 0, + "content": "9: train \\(\\Theta^t\\) by minimizing \\(\\mathcal{L}_t\\) from Eq. 12" + }, + { + "type": "code", + "bbox": [ + 0.084, + 0.485, + 0.201, + 0.497 + ], + "angle": 0, + "content": "10: end while" + }, + { + "type": "code", + "bbox": [ + 0.084, + 0.5, + 0.16, + 0.512 + ], + "angle": 0, + "content": "11: end for" + }, + { + "type": "list", + "bbox": [ + 0.084, + 0.348, + 0.446, + 0.512 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.543, + 0.47, + 0.635 + ], + "angle": 0, + "content": "and detailed classification and image reconstruction knowledge. We illustrate the overall framework in Fig. 2. Bilateral fusion at the embedding-level aims to improve representations diversity. Reconstruction learning at the image-level yields high-quality replay data and stable self-supervision for CIL." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.653, + 0.469, + 0.744 + ], + "angle": 0, + "content": "Embedding fusion. In the following we use \\(F_{\\theta[:1]}\\) and \\(F_{\\theta[1:]}\\) to denote our transformer encoder's first and following blocks. Let \\(H_{\\theta}\\) and \\(E_{\\theta}\\) represent the detailed block and embedding fusion module in Fig. 2, which are standard MLP layers and attention blocks, respectively. The classification loss is computed as:" + }, + { + "type": "equation", + "bbox": [ + 0.202, + 0.759, + 0.468, + 0.775 + ], + "angle": 0, + "content": "\\[\nf = F _ {\\theta [: 1 ]} (\\operatorname {m a s k} (x, r)) \\tag {1}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.205, + 0.778, + 0.468, + 0.793 + ], + "angle": 0, + "content": "\\[\nz = E _ {\\theta} \\left(F _ {\\theta [ 1: ]} (f), H _ {\\theta} (f)\\right) \\tag {2}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.148, + 0.797, + 0.468, + 0.814 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {t} ^ {\\mathrm {c l s}} (x, y) = \\mathcal {L} _ {\\mathrm {c e}} \\left(G _ {\\phi} (z), y\\right), \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.827, + 0.469, + 0.904 + ], + "angle": 0, + "content": "where \\(\\mathrm{mask}(x,r)\\) denotes applying random masking with ratio \\(r\\) on image \\(x\\), \\(f\\) is the embedding extracted by the first encoder block, which is the input to the two branches of our Bilateral MAE, and \\(G_{\\phi}(z)\\) is the estimated class distribution used for in the cross entropy loss." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.289 + ], + "angle": 0, + "content": "Image fusion with detailed loss. For the detailed head and corresponding loss, we discovered that working in the frequency domain makes it easier for the network to attend to high-frequency details, which is exactly what the detailed branch should reconstruct. We define a frequency-masking function \\( M(\\cdot) \\) that converts its argument (an image patch) to the frequency domain, then masks out low frequencies using a circular mask around the origin. As shown in Fig. 2, the MAE decoder is shared by the two branches of our model since they have similar reconstruction tasks, as well as input and output shapes. Let \\( D_{\\theta} \\) be this shared decoder, then the image-level outputs of the two branches and the reconstruction loss \\( \\mathcal{L}_t^{\\mathrm{rec}} \\) are:" + }, + { + "type": "equation", + "bbox": [ + 0.603, + 0.301, + 0.891, + 0.318 + ], + "angle": 0, + "content": "\\[\nf = F _ {\\theta [: 1 ]} (\\operatorname {m a s k} (x, r)) \\tag {4}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.599, + 0.32, + 0.891, + 0.337 + ], + "angle": 0, + "content": "\\[\nx ^ {\\prime} = D _ {\\theta} \\left(F _ {\\theta [ 1: ]} (f)\\right) \\tag {5}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.596, + 0.338, + 0.891, + 0.355 + ], + "angle": 0, + "content": "\\[\nx ^ {\\prime \\prime} = \\text {i f t 2} \\left(M \\left(D _ {\\theta} \\left(H _ {\\theta} (f)\\right)\\right)\\right) \\tag {6}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.604, + 0.357, + 0.891, + 0.373 + ], + "angle": 0, + "content": "\\[\n\\hat {x} = x ^ {\\prime} + x ^ {\\prime \\prime} \\tag {7}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.585, + 0.376, + 0.891, + 0.393 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {t} ^ {\\text {r e c}} = \\mathcal {L} _ {\\text {m s e}} (x, \\hat {x}), \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.404, + 0.891, + 0.435 + ], + "angle": 0, + "content": "where \\( x' \\) and \\( x'' \\) are the main and residual detailed outputs, respectively, and ifft2 is the inverse Fast Fourier Transform." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.435, + 0.891, + 0.496 + ], + "angle": 0, + "content": "The detailed loss \\(\\mathcal{L}_t^{\\mathrm{det}}\\) also makes use of the frequencymasking function \\(M\\) to compare the output of the detailed branch and the difference between two MAE reconstructions of the input image:" + }, + { + "type": "equation", + "bbox": [ + 0.551, + 0.509, + 0.891, + 0.524 + ], + "angle": 0, + "content": "\\[\n\\hat {x} _ {1} = D _ {\\theta} \\left(F _ {\\theta} \\left(\\operatorname {m a s k} \\left(x, r _ {1}\\right)\\right)\\right) \\tag {9}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.551, + 0.528, + 0.891, + 0.543 + ], + "angle": 0, + "content": "\\[\n\\hat {x} _ {2} = D _ {\\theta} \\left(F _ {\\theta} (\\operatorname {m a s k} (x, r _ {2}))\\right) \\tag {10}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.538, + 0.545, + 0.891, + 0.563 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {t} ^ {\\mathrm {d e t}} = | | M \\left(D _ {\\theta} \\left(H _ {\\theta} (f)\\right) - M \\left(\\hat {x} _ {2} - \\hat {x} _ {1}\\right) \\right| | _ {1}, \\tag {11}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.575, + 0.891, + 0.664 + ], + "angle": 0, + "content": "where \\(\\hat{x}_1\\) and \\(\\hat{x}_2\\) are two reconstructed images (detached from the gradient computation graph) using different masking ratios \\(r_1\\) and \\(r_2\\), respectively. The residual difference \\(\\hat{x}_2 - \\hat{x}_1\\) is used as supervision in the frequency domain for the detailed branch in loss \\(\\mathcal{L}_t^{\\mathrm{det}}\\). An illustration can be found in Fig. 3." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.665, + 0.891, + 0.711 + ], + "angle": 0, + "content": "A weighted sum of classification loss \\(\\mathcal{L}_t^{\\mathrm{cls}}\\), reconstruction loss \\(\\mathcal{L}_t^{\\mathrm{rec}}\\), and detail loss \\(\\mathcal{L}_t^{\\mathrm{det}}\\) is used as the overall loss for training:" + }, + { + "type": "equation", + "bbox": [ + 0.561, + 0.723, + 0.891, + 0.74 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {t} = \\lambda_ {\\mathrm {c l s}} \\mathcal {L} _ {t} ^ {\\mathrm {c l s}} + \\lambda_ {\\mathrm {r e c}} \\mathcal {L} _ {t} ^ {\\mathrm {r e c}} + \\lambda_ {\\mathrm {d e t}} \\mathcal {L} _ {t} ^ {\\mathrm {d e t}}. \\tag {12}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.752, + 0.843, + 0.768 + ], + "angle": 0, + "content": "Pseudocode for our method is given in Algorithm 1." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.782, + 0.705, + 0.799 + ], + "angle": 0, + "content": "4. Experimental Results" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.807, + 0.794, + 0.822 + ], + "angle": 0, + "content": "4.1. Benchmarks and Implementation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Datasets and settings. We experiment on three datasets: CIFAR-100 [16], ImageNet-Subset, and ImageNet-Full [6] to evaluate the performance of our approach. For CIFAR-100 and ImageNet-Subset, we test on 10-, 20- and 50-task scenarios, all with equal numbers of classes per task. We" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19107" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.165, + 0.1, + 0.373, + 0.265 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.379, + 0.1, + 0.588, + 0.265 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.593, + 0.1, + 0.801, + 0.265 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.17, + 0.267, + 0.794, + 0.281 + ], + "angle": 0, + "content": "Figure 4. Performance evolution over incremental tasks on CIFAR-100 on 10-, 20- and 50-task scenarios." + }, + { + "type": "table", + "bbox": [ + 0.207, + 0.292, + 0.766, + 0.446 + ], + "angle": 0, + "content": "
MethodN=10N=20N=50
Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓
iCaRL [29]65.2750.7431.2361.2043.7532.4056.0836.6236.59
UCIR [12]58.6643.3935.6758.1740.6337.7556.8637.0938.13
BiC [36]68.8053.5428.4466.4847.0229.3062.0941.0434.27
PODNet [8]58.0341.0541.4753.9735.0236.7051.1932.9940.42
DER w/o P [40]75.3665.2215.0274.0962.4823.5572.4159.0826.73
DER [40]74.6464.3515.7873.9862.5523.4772.0559.7626.59
DyTox [9]75.4762.1015.4375.1059.4121.6073.8957.2124.22
Ours79.1268.4012.1778.7665.2214.3976.9563.1218.34
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.447, + 0.887, + 0.461 + ], + "angle": 0, + "content": "Table 1. Results on CIFAR-100 in average accuracy (%), last phase accuracy (%), and forgetting F (% on 10-, 20- and 50-task scenarios." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.486, + 0.47, + 0.563 + ], + "angle": 0, + "content": "evaluate the 10-task setting for ImageNet-Full in which 100 new classes are included in each task. To measure the overall accuracy after all tasks during training, we report the average accuracy of learned tasks after each task and the accuracy of all tasks at the end of incremental learning." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.583, + 0.47, + 0.718 + ], + "angle": 0, + "content": "Implementation details. We use the same network for all datasets. Models are trained from scratch to prevent data leakage with batch size of 1024 using Adam [14] with initial learning rate 1e-4 and cosine decay. The loss weights from Eq. 12 are set to \\(\\lambda_{cls} = 0.01\\), \\(\\lambda_{rec} = 1.0\\) and \\(\\lambda_{det} = 1.0\\). The masking ratios are set to \\(r = 0.75\\), \\(r_1 = 0.75\\), and \\(r_2 = 0.4\\). Each task is trained for 400 epochs. For exemplar-based methods from the literature, we store 20 samples for each classes (as is common practice)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.471, + 0.902 + ], + "angle": 0, + "content": "We use 5 transformer blocks for the encoder and 1 for the decoder. All transformer blocks have an embedding dimension of 384 and 12 self-attention heads. This design differs from the original MAE as it is much more lightweight. We save image patches occupying the same amount of memory as other methods which store 20 full images per class. For example, we select 80 images and randomly save only \\(25\\%\\) patches from each using a masking ratio of 0.75 (thus only occupying the same space as 20 whole images). The detailed block is implemented with a 3-layer MLP keeping the dimension at 384. Further details about network architecture are given in the Supplementary Material." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.486, + 0.819, + 0.502 + ], + "angle": 0, + "content": "4.2. Comparison with the state-of-the-art" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.509, + 0.892, + 0.6 + ], + "angle": 0, + "content": "In this section we compare our approach with the state-of-the-art, including DER [40] and DyTox [9]. In all plots and tables, \"DER w/o P\" denotes DER [40] without pruning, therefore leading to more parameters being added across tasks. DyTox [9] also uses a transformer architecture and we use the official codebase to reproduce its results." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.614, + 0.893, + 0.765 + ], + "angle": 0, + "content": "CIFAR-100. We report results in average accuracy (Avg), the accuracy after the last task (Last), and average forgetting (F) in Table 1. It is clear that under each setting our method outperforms others by a large margin. For longer task sequences, our bilateral MAE benefits from self-supervised reconstruction and richer replay data and it forgets much less compared to other methods. An overall accuracy curve is given in Fig. 4. Using the same amount of replay storage, our method outperforms DyTox by about \\(6\\%\\) in accuracy after the last task in all three scenarios." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.895, + 0.902 + ], + "angle": 0, + "content": "ImageNet-Subset and ImageNet-Full. We report performance on ImageNet-Subset and ImageNet-Full in Tables 2 and 3, respectively. Our method outperforms DyTox [9] by \\(1.19\\%\\), \\(2.53\\%\\), and \\(2.85\\%\\) absolute gain in accuracy after the last task on the 10-, 20- and 50-task settings, respectively. The higher average accuracy during each phase and lower forgetting also demonstrates the effectiveness of our method in alleviating forgetting. We also" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19108" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.156, + 0.101, + 0.37, + 0.27 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.373, + 0.101, + 0.589, + 0.27 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.595, + 0.102, + 0.808, + 0.27 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.253, + 0.272, + 0.712, + 0.285 + ], + "angle": 0, + "content": "Figure 5. Performance evolution over incremental tasks on ImageNet-Subset." + }, + { + "type": "table", + "bbox": [ + 0.207, + 0.296, + 0.766, + 0.42 + ], + "angle": 0, + "content": "
MethodN=10N=20N=50
Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓
BiC [36]64.9655.0731.3259.4049.3534.7053.7544.5640.23
PODNet [8]63.4451.7535.6355.1145.3741.7051.7242.9444.65
DER w/o P [40]77.1866.7014.8672.7061.7420.7670.4458.8724.20
DER [40]76.1266.0615.0972.5661.5120.4669.7758.1925.35
DyTox [9]77.1569.1014.6673.1361.8717.3271.5160.0220.54
Ours79.5470.2912.0475.2064.4014.8974.4262.8717.22
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.422, + 0.882, + 0.435 + ], + "angle": 0, + "content": "Table 2. Results on ImageNet-Subset in average and last phase accuracy (%) and forgetting rate F (%) on 10-, 20- and 50-task scenarios." + }, + { + "type": "table", + "bbox": [ + 0.119, + 0.457, + 0.431, + 0.58 + ], + "angle": 0, + "content": "
Methodtop-1top-5
Avg ↑Last ↑Avg ↑Last ↑
iCaRL [29]38.4022.7063.7044.00
Simple-DER66.6359.2485.6280.76
DER w/o P [40]68.8460.1688.1782.86
DER [40]66.7358.6287.0881.89
DyTox [9]71.2963.3488.5984.49
Ours74.7666.1591.4387.13
" + }, + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.582, + 0.432, + 0.595 + ], + "angle": 0, + "content": "Table 3. Results on ImageNet-Full for 10 incremental tasks." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.624, + 0.47, + 0.716 + ], + "angle": 0, + "content": "illustrate the performance evolution on ImageNet-Subset in Fig. 5. Our method has accuracy similar to DyTox in the first task, but in later tasks our method surpasses all others, especially for long task sequences. On the larger-scale ImageNet-Full, our Bilateral MAE significantly outperforms other methods by about \\(3\\%\\) in all metrics." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.73, + 0.231, + 0.745 + ], + "angle": 0, + "content": "4.3. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Ablations on different components. Our bilateral MAE consists of a self-supervised reconstruction task, generated data for replay, and a bilateral MAE branch for image- and embedding-level fusion. We ablate on these three factors in Table 4. These three major components in our method have different functions and they cooperate to boost performance compared with the baseline by about \\(6\\%\\). We observe that: (a) More high-quality replay data has a direct contribution to the performance and masking ration of \\(r = 0.75\\) masking ratio yields \\(4 \\times\\) replay for the same storage cost as the" + }, + { + "type": "table", + "bbox": [ + 0.508, + 0.457, + 0.887, + 0.55 + ], + "angle": 0, + "content": "
MethodReplayReconstructionBilateralAvgLast
Baseline73.4062.31
Variants✓75.8864.35
✓✓77.4866.54
✓✓✓79.1268.40
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.55, + 0.892, + 0.618 + ], + "angle": 0, + "content": "Table 4. Ablative experiments on each component of our proposed method in the 10-task setting on CIFAR-100. Replay denotes using generated data from MAE for replay, Reconstruction means applying the self-supervised reconstruction loss, and Bilateral indicates introduction the detailed branch of the MAE." + }, + { + "type": "table", + "bbox": [ + 0.589, + 0.634, + 0.806, + 0.727 + ], + "angle": 0, + "content": "
rData SourceAvgLast
0.60Generated77.5067.37
0.75Generated79.1268.40
0.90Generated77.1267.02
N/AReal79.5768.87
" + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.727, + 0.894, + 0.797 + ], + "angle": 0, + "content": "Table 5. Ablation on the masking ratio and quality of generated data. Experiments are on CIFAR-100 in the 10-task setting and we report top-1 accuracy in %. Data Source indicates whether replay is generated or real. In the last row we replay a selection of of real images equivalent in storage size to using \\( r_1 = 0.75 \\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.827, + 0.894, + 0.904 + ], + "angle": 0, + "content": "baseline. (b) The reconstruction loss serves as effective self-supervision and improves performance by about \\(2\\%\\) in average accuracy. (c) The bilateral architecture works well by improving replay data generation quality and introducing image and embedding-level supervision." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "19109" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.191, + 0.089, + 0.357, + 0.145 + ], + "angle": 0, + "content": "
DomainAvgLast
Spatial77.4565.93
Frequency79.1268.40
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.076, + 0.145, + 0.47, + 0.201 + ], + "angle": 0, + "content": "Table 6. Ablative experiments on the detailed head. Experiments are on CIFAR-100 in the 10-task setting and we report the top-1 accuracy in \\(\\%\\) . Domain denotes to which domain our loss is applied." + }, + { + "type": "image", + "bbox": [ + 0.128, + 0.231, + 0.403, + 0.394 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.397, + 0.47, + 0.425 + ], + "angle": 0, + "content": "Figure 6. Ablation on masking ratio \\( r_2 \\) in \\( \\mathcal{L}_t^{\\mathrm{det}} \\). The other masking ratio \\( r_1 \\) is set to \\( 75\\% \\) as the reference." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.449, + 0.471, + 0.646 + ], + "angle": 0, + "content": "Masking ratio. A key parameter of MAE [11] is the masking ratio \\( r \\). There is trade-off on \\( r \\): too large \\( r \\) (e.g. 0.95) leads to poor reconstruction, which influences the quality of replay data and causes more serious forgetting. However, too small \\( r \\) yields a limited extra amount of replay data (e.g. we can afford only about \\( 11\\% \\) extra replay data when \\( r \\) is 0.10). The results in Table 5 show that \\( r = 0.75 \\) is a good trade-off for our bilateral MAE. To verify the quality of generated data for replay, also include results using original images for replay in place of generated ones. Results in rows 2 and 4 of Table 5 show that our method achieves good quality images with less than \\( 0.5\\% \\) accuracy difference compared to replaying real images." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.66, + 0.47, + 0.766 + ], + "angle": 0, + "content": "Frequency domain for the detailed loss. We implemented the detailed loss by converting embeddings from the spatial domain to the frequency domain. This aims to allow concentration on high-frequency information which matches the learning objective of the detailed MAE branch. As shown in Table 6, it is beneficial to make this conversion as it leads to a more than \\(2\\%\\) gain at the last task." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.781, + 0.471, + 0.901 + ], + "angle": 0, + "content": "Ablation on \\( r_1 \\) and \\( r_2 \\) in the detailed loss. We set \\( r_1 \\) to 0.75 for all these experiments as a reference and we vary \\( r_2 \\) used for computing the ground truth of the detailed loss. The trade-off on \\( r_2 \\) is that large \\( r_2 \\) results in small differences between the reconstructed results from mask ratios \\( r_1 \\) and \\( r_2 \\) and therefore there is little information in the supervisory signal for the detailed loss and the impact of the detailed branch is reduced. On the other hand, too small" + }, + { + "type": "table", + "bbox": [ + 0.501, + 0.089, + 0.892, + 0.169 + ], + "angle": 0, + "content": "
MethodParameters (M)Avg ↑Last ↑F ↓
DER w/o P112.2775.3665.2215.02
DyTox10.7375.4762.1015.43
Ours (MLP size = 1536)12.8979.1268.4012.17
Ours (MLP size = 768)9.3578.3667.5212.90
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.5, + 0.17, + 0.892, + 0.21 + ], + "angle": 0, + "content": "Table 7. Comparison of model sizes. We compare two versions of our Bilateral MAE and competing models. Experiments were conducted on CIFAR-100 with 10 tasks." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.227, + 0.892, + 0.318 + ], + "angle": 0, + "content": "\\(r_2\\) (e.g. 0.10) maintains most of the residual part of reconstructed images from the main branch, which may bring weak supervision for the main branch and slow its training. We show results for a range of \\(r_2\\) values in Fig. 6. These results show that an \\(r_2\\) of about 0.40 is good for providing supervision to the detailed branch of our MAE." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.341, + 0.892, + 0.508 + ], + "angle": 0, + "content": "Model and exemplar sizes. To compare the effectiveness of different methods, normally models with the same or similar number of parameters are used with an equal number of exemplars. In our approach, we adapt the original MAE to be more lightweight and the number of parameters is comparable to or even smaller than DyTox, as shown in Table 7 (last row). We set the masking ratio to \\(75\\%\\) by default and save 80 exemplars per class, and therefore the storage size for both models and exemplars is similar since our stored image patches require exactly the same as baselines using only 20 exemplars." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.531, + 0.892, + 0.698 + ], + "angle": 0, + "content": "Ablation on effective buffer size. In Table 8 we compare our method with Dytox using the same buffer size by masking input image patches in input to DyTox. All three rows use the same memory size for storing exemplars. Using 80 exemplars with masking ratio of \\(75\\%\\), DyTox (last row) achieves better performance than when using 20 full-image exemplars. It still performs worse than our approach, which shows that our performance gain does not simply come from the additional exemplars, but also from the integration of the MAE into our bilateral architecture with the Detailed Branch." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.722, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Reconstruction analysis. We illustrate results of image reconstruction in the 10-task setting on ImageNet-Subset in Fig. 7. Randomly selected images from tasks 1, 4, 7, and 10 are shown in the left column. Our bilateral MAE learns to reconstruct images in a task-agnostic way, which helps generate reasonable results for future tasks even before learning them. The detailed branch of our MAE learns to reconstruct high-frequency details complementary to the main branch. The results from the main branch sometimes lack sample-specific characteristics, but with the help of our proposed detailed branch the reconstructions are more accurate and provide better generated replay data." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "19110" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.083, + 0.087, + 0.155, + 0.26 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.104, + 0.261, + 0.144, + 0.272 + ], + "angle": 0, + "content": "Image" + }, + { + "type": "image", + "bbox": [ + 0.172, + 0.089, + 0.338, + 0.261 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.223, + 0.262, + 0.262, + 0.272 + ], + "angle": 0, + "content": "Task 1" + }, + { + "type": "image", + "bbox": [ + 0.356, + 0.089, + 0.521, + 0.261 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.407, + 0.262, + 0.446, + 0.272 + ], + "angle": 0, + "content": "Task 4" + }, + { + "type": "image", + "bbox": [ + 0.538, + 0.089, + 0.703, + 0.261 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.589, + 0.262, + 0.63, + 0.272 + ], + "angle": 0, + "content": "Task 7" + }, + { + "type": "image", + "bbox": [ + 0.721, + 0.089, + 0.886, + 0.261 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.769, + 0.262, + 0.817, + 0.272 + ], + "angle": 0, + "content": "Task 10" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.273, + 0.894, + 0.314 + ], + "angle": 0, + "content": "Figure 7. Reconstructed images from ImageNet-Subset in the 10-task setting. Four original images were selected from tasks 1, 4, 6, and 10 and are shown on the left. In the remaining columns we show reconstructed images using our combined Bilateral MAE (left), only the detailed branch of our MAE (middle), and only the main branch of our MAE (right)." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.336, + 0.47, + 0.4 + ], + "angle": 0, + "content": "
MethodBufferMemory size25% PatchesImagesAcc(%)
Ours801x✓68.40
DyTox201x✓62.10
DyToxt801x✓65.46
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.077, + 0.4, + 0.471, + 0.456 + ], + "angle": 0, + "content": "Table 8. Ablation on effective buffer size with equal memory usage. Dytox† represents applying a mask ratio \\( r = 75\\% \\) directly to stored image exemplars in order to have the same number of exemplars and storage size for DyTox as in our setting." + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.464, + 0.466, + 0.639 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.127, + 0.654, + 0.419, + 0.668 + ], + "angle": 0, + "content": "Figure 8. Comparison of feature space density \\(\\pi\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.672, + 0.47, + 0.825 + ], + "angle": 0, + "content": "More generalizable representations help CIL. We calculated the feature space density metric [32] for different methods following PASS [46]: \\(\\pi = \\pi_{intra} / \\pi_{inter}\\), where \\(\\pi_{intra}\\) denotes the average cosine similarity within the same class and \\(\\pi_{inter}\\) denotes the one within different classes. Increased feature space density is associated with stronger generalization under data shift [46]. We then compared feature space density after training all tasks, as shown in Figure 8 above. It is clear that Ours yields significantly higher density than other methods." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Ablation with other efficient replay methods. We compared the replay samples generated by MAE in our framework with a variety of memory-efficient methods based on latent replay [19], synthesized exemplars [20], down-" + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.336, + 0.89, + 0.449 + ], + "angle": 0, + "content": "
MetricMemoryAvg↑Last↑
Latent replay (CVPRW'20) [19]-62.4451.30
MCIL (CVPR'20) [20]6063.2553.12
Down-scaled (TNNLS'21) [45]6067.0455.40
JPEG compression (ICLR'22) [34]6072.3461.32
CIM (CVPR'23) [22]6075.3063.05
Ours6079.1268.40
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.5, + 0.449, + 0.892, + 0.49 + ], + "angle": 0, + "content": "Table 9. Comparison of our bilateral MAE framework with other memory-efficient methods on the CIFAR-100 10-task setting. Memory indicates the required storage space per class (in KB)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.516, + 0.892, + 0.593 + ], + "angle": 0, + "content": "scaling [45], JPEG image compression [34], and CIM [22] (foreground extraction and background compression). All these methods use the same amount of storage (except Latent Replay uses a GAN with 4.5M parameters), while our approach achieves consistently higher performance." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.62, + 0.628, + 0.635 + ], + "angle": 0, + "content": "5. Conclusions" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.65, + 0.892, + 0.788 + ], + "angle": 0, + "content": "In this work, we demonstrate that Masked Autoencoders are efficient incremental learners. Our approach stores random image patches as exemplars and it can reconstruct high-quality images from only partial information for replay. Furthermore, we propose a novel bilateral MAE architecture which further improves embedding diversity and reconstruction quality. Our Bilateral MAE approach significantly outperforms previous state-of-the-art methods for the same exemplar storage cost." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Acknowledgements This work is funded by NSFC (NO. 62225604, 62206135), and the Fundamental Research Funds for the Central Universities (Nankai University, 070-63233085). Computation is supported by the Supercomputing Center of Nankai University." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "19111" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.468, + 0.157 + ], + "angle": 0, + "content": "[1] Rahaf Aljundi, Punarjay Chakravarty, and Tinne Tuytelaars. Expert gate: Lifelong learning with a network of experts. In IEEE Conf. Comput. Vis. Pattern Recog., 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.16, + 0.468, + 0.213 + ], + "angle": 0, + "content": "[2] Eden Belouadah, Adrian Popescu, and Ioannis Kanellos. A comprehensive study of class incremental learning algorithms for visual tasks. Neural Networks, 135:38-54, 2021. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.217, + 0.468, + 0.258 + ], + "angle": 0, + "content": "[3] Arslan Chaudhry, Marc'Aurelio Ranzato, Marcus Rohrbach, and Mohamed Elhoseiny. Efficient lifelong learning with a gem. In Int. Conf. Learn. Represent., 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.26, + 0.468, + 0.315 + ], + "angle": 0, + "content": "[4] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning of visual representations. In International conference on machine learning, pages 1597-1607. PMLR, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.317, + 0.468, + 0.371 + ], + "angle": 0, + "content": "[5] Matthias Delange, Rahaf Aljundi, Marc Masana, Sarah Parisot, Xu Jia, Ales Leonardis, Greg Slabaugh, and Tinne Tuytelaars. A continual learning survey: Defying forgetting in classification tasks. TPAMI, 2021. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.374, + 0.468, + 0.427 + ], + "angle": 0, + "content": "[6] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In IEEE Conf. Comput. Vis. Pattern Recog., 2009. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.431, + 0.468, + 0.471 + ], + "angle": 0, + "content": "[7] Carl Doersch, Abhinav Gupta, and Alexei A Efros. Unsupervised visual representation learning by context prediction. In Int. Conf. Comput. Vis., 2015. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.474, + 0.468, + 0.529 + ], + "angle": 0, + "content": "[8] Arthur Douillard, Matthieu Cord, Charles Ollion, Thomas Robert, and Eduardo Valle. Podnet: Pooled outputs distillation for small-tasks incremental learning. In Eur. Conf. Comput. Vis., 2020. 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.531, + 0.468, + 0.586 + ], + "angle": 0, + "content": "[9] Arthur Douillard, Alexandre Rame, Guillaume Couairon, and Matthieu Cord. Dytox: Transformers for continual learning with dynamic token expansion. In IEEE Conf. Comput. Vis. Pattern Recog., 2022. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.588, + 0.468, + 0.629 + ], + "angle": 0, + "content": "[10] Spyros Gidaris, Praveer Singh, and Nikos Komodakis. Unsupervised representation learning by predicting image rotations. In Int. Conf. Learn. Represent., 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.631, + 0.468, + 0.685 + ], + "angle": 0, + "content": "[11] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In IEEE Conf. Comput. Vis. Pattern Recog., 2022. 1, 2, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.688, + 0.468, + 0.742 + ], + "angle": 0, + "content": "[12] Saihui Hou, Xinyu Pan, Chen Change Loy, Zilei Wang, and Dahua Lin. Learning a unified classifier incrementally via rebalancing. In IEEE Conf. Comput. Vis. Pattern Recog., 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.746, + 0.468, + 0.772 + ], + "angle": 0, + "content": "[13] David Isele and Akansel Cosgun. Selective experience replay for lifelong learning. In AAAI, 2018. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.775, + 0.468, + 0.814 + ], + "angle": 0, + "content": "[14] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. In Int. Conf. Learn. Represent., 2015. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.468, + 0.899 + ], + "angle": 0, + "content": "[15] James Kirkpatrick, Razvan Pascanu, Neil Rabinowitz, Joel Veness, Guillaume Desjardins, Andrei A Rusu, Kieran Milan, John Quan, Tiago Ramalho, Agnieszka Grabska-Barwinska, et al. Overcoming catastrophic forgetting in neural networks. Proceedings of the national academy of sciences, 2017. 1, 2" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.468, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "[16] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images, 2009. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.122, + 0.892, + 0.148 + ], + "angle": 0, + "content": "[17] Zhizhong Li and Derek Hoiem. Learning without forgetting. In Eur. Conf. Comput. Vis., 2016. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.15, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[18] Feng Liang, Yangguang Li, and Diana Marculescu. Supmae: Supervised masked autoencoders are efficient vision learners. arXiv preprint arXiv:2205.14540, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.192, + 0.892, + 0.259 + ], + "angle": 0, + "content": "[19] Xialei Liu, Chenshen Wu, Mikel Menta, Luis Herranz, Bogdan Raducanu, Andrew D Bagdanov, Shangling Jui, and Joost van de Weijer. Generative feature replay for class incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog. Worksh., 2020. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.261, + 0.892, + 0.315 + ], + "angle": 0, + "content": "[20] Yaoyao Liu, Yuting Su, An-An Liu, Bernt Schiele, and Qianru Sun. Mnemonics training: Multi-class incremental learning without forgetting. In IEEE Conf. Comput. Vis. Pattern Recog., pages 12245-12254, 2020. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.317, + 0.892, + 0.357 + ], + "angle": 0, + "content": "[21] David Lopez-Paz and Marc'Aurelio Ranzato. Gradient episodic memory for continual learning. Adv. Neural Inform. Process. Syst., 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.359, + 0.892, + 0.413 + ], + "angle": 0, + "content": "[22] Zilin Luo, Yaoyao Liu, Bernt Schiele, and Qianru Sun. Class-incremental exemplar compression for class-incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., pages 11371-11380, 2023. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.415, + 0.892, + 0.455 + ], + "angle": 0, + "content": "[23] Arun Mallya, Dillon Davis, and Svetlana Lazebnik. Piggyback: Adapting a single network to multiple tasks by learning to mask weights. In Eur. Conf. Comput. Vis., 2018. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.457, + 0.892, + 0.496 + ], + "angle": 0, + "content": "[24] Arun Mallya and Svetlana Lazebnik. Packnet: Adding multiple tasks to a single network by iterative pruning. In IEEE Conf. Comput. Vis. Pattern Recog., 2018. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.498, + 0.892, + 0.565 + ], + "angle": 0, + "content": "[25] Marc Masana, Xialei Liu, Barttomiej Twardowski, Mikel Menta, Andrew D. Bagdanov, and Joost van de Weijer. Class-incremental learning: Survey and performance evaluation on image classification. IEEE Trans. Pattern Anal. Mach. Intell., 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.568, + 0.892, + 0.621 + ], + "angle": 0, + "content": "[26] Michael McCloskey and Neal J Cohen. Catastrophic interference in connectionist networks: The sequential learning problem. In *Psychology of learning and motivation*. Elsevier, 1989. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.624, + 0.892, + 0.663 + ], + "angle": 0, + "content": "[27] Mehdi Noroozi and Paolo Favaro. Unsupervised learning of visual representations by solving jigsaw puzzles. In Eur. Conf. Comput. Vis., 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.666, + 0.892, + 0.704 + ], + "angle": 0, + "content": "[28] Quang Pham, Chenghao Liu, and Steven Hoi. Dualnet: Continual learning, fast and slow. Adv. Neural Inform. Process. Syst., 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.707, + 0.892, + 0.761 + ], + "angle": 0, + "content": "[29] Sylvestre-Alvise Rebuffi, Alexander Kolesnikov, Georg Sperl, and Christoph H Lampert. icarl: Incremental classifier and representation learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2017. 1, 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.763, + 0.892, + 0.816 + ], + "angle": 0, + "content": "[30] Matthew Riemer, Ignacio Cases, Robert Ajemian, Miao Liu, Irina Rish, Yuhai Tu, and Gerald Tesauro. Learning to learn without forgetting by maximizing transfer and minimizing interference. In Int. Conf. Learn. Represent., 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.818, + 0.892, + 0.859 + ], + "angle": 0, + "content": "[31] David Rolnick, Arun Ahuja, Jonathan Schwarz, Timothy Lillicrap, and Gregory Wayne. Experience replay for continual learning. Adv. Neural Inform. Process. Syst., 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.861, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[32] Karsten Roth, Timo Milbich, Samarth Sinha, Prateek Gupta, Bjorn Ommer, and Joseph Paul Cohen. Revisiting training strategies and generalization performance in deep metric" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19112" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.468, + 0.119 + ], + "angle": 0, + "content": "learning. In Int. Mach. Learn., pages 8242-8252. PMLR, 2020. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.469, + 0.177 + ], + "angle": 0, + "content": "[33] James Smith, Yen-Chang Hsu, Jonathan Balloch, Yilin Shen, Hongxia Jin, and Zsolt Kira. Always be dreaming: A new approach for data-free class-incremental learning. In Int. Conf. Comput. Vis., 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.179, + 0.469, + 0.246 + ], + "angle": 0, + "content": "[34] Liyuan Wang, Xingxing Zhang, Kuo Yang, Longhui Yu, Chongxuan Li, Lanqing Hong, Shifeng Zhang, Zhenguo Li, Yi Zhong, and Jun Zhu. Memory replay with data compression for continual learning. In Int. Conf. Learn. Represent., 2022. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.249, + 0.469, + 0.303 + ], + "angle": 0, + "content": "[35] Chenshen Wu, Luis Herranz, Xialei Liu, Joost van de Weijer, Bogdan Raducanu, et al. Memory replay gans: Learning to generate new categories without forgetting. Adv. Neural Inform. Process. Syst., 2018. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.305, + 0.469, + 0.359 + ], + "angle": 0, + "content": "[36] Yue Wu, Yinpeng Chen, Lijuan Wang, Yuancheng Ye, Zicheng Liu, Yandong Guo, and Yun Fu. Large scale incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2019. 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.362, + 0.469, + 0.415 + ], + "angle": 0, + "content": "[37] Zhirong Wu, Yuanjun Xiong, Stella X Yu, and Dahua Lin. Unsupervised feature learning via non-parametric instance discrimination. In IEEE Conf. Comput. Vis. Pattern Recog., 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.418, + 0.469, + 0.459 + ], + "angle": 0, + "content": "[38] Ye Xiang, Ying Fu, Pan Ji, and Hua Huang. Incremental learning using conditional adversarial networks. In Int. Conf. Comput. Vis., 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.462, + 0.468, + 0.488 + ], + "angle": 0, + "content": "[39] Ju Xu and Zhanxing Zhu. Reinforced continual learning. Adv. Neural Inform. Process. Syst., 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.49, + 0.469, + 0.543 + ], + "angle": 0, + "content": "[40] Shipeng Yan, Jiangwei Xie, and Xuming He. Der: Dynamically expandable representation for class incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2021. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.547, + 0.469, + 0.613 + ], + "angle": 0, + "content": "[41] Hongxu Yin, Pavlo Molchanov, Jose M Alvarez, Zhizhong Li, Arun Mallya, Derek Hoiem, Niraj K Jha, and Jan Kautz. Dreaming to distill: Data-free knowledge transfer via deep-inversion. In IEEE Conf. Comput. Vis. Pattern Recog., 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.617, + 0.469, + 0.672 + ], + "angle": 0, + "content": "[42] Jure Zbontar, Li Jing, Ishan Misra, Yann LeCun, and Stéphane Deny. Barlow twins: Self-supervised learning via redundancy reduction. In International Conference on Machine Learning, pages 12310-12320. PMLR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.674, + 0.469, + 0.728 + ], + "angle": 0, + "content": "[43] Mengyao Zhai, Lei Chen, Frederick Tung, Jiawei He, Megha Nawhal, and Greg Mori. Lifelong gan: Continual learning for conditional image generation. In Int. Conf. Comput. Vis., 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.731, + 0.469, + 0.784 + ], + "angle": 0, + "content": "[44] Junting Zhang, Jie Zhang, Shalini Ghosh, Dawei Li, Serafettin Tasci, Larry Heck, Heming Zhang, and C-C Jay Kuo. Class-incremental learning via deep model consolidation. In WACV, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.787, + 0.469, + 0.828 + ], + "angle": 0, + "content": "[45] Hanbin Zhao, Hui Wang, Yongjian Fu, Fei Wu, and Xi Li. Memory-efficient class-incremental learning for image classification. TNNLS, 33(10):5966-5977, 2021. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.83, + 0.469, + 0.885 + ], + "angle": 0, + "content": "[46] Fei Zhu, Xu-Yao Zhang, Chuang Wang, Fei Yin, and ChengLin Liu. Prototype augmentation and self-supervision for incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2021. 2, 8" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.885 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19113" + } + ] +] \ No newline at end of file diff --git a/2023/Masked Autoencoders are Efficient Class Incremental Learners/3431d5c0-b1b6-47da-9e6e-bca6fba5a382_origin.pdf b/2023/Masked Autoencoders are Efficient Class Incremental Learners/3431d5c0-b1b6-47da-9e6e-bca6fba5a382_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..2e21149c1c8c9003866adbdc8787191a4e005dcb --- /dev/null +++ b/2023/Masked Autoencoders are Efficient Class Incremental Learners/3431d5c0-b1b6-47da-9e6e-bca6fba5a382_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:448216192c715d710da91df208b8671d59fecae23faf5108fb941ba8eb0c54cc +size 835309 diff --git a/2023/Masked Autoencoders are Efficient Class Incremental Learners/full.md b/2023/Masked Autoencoders are Efficient Class Incremental Learners/full.md new file mode 100644 index 0000000000000000000000000000000000000000..4af52ad72a9e54b94d1a8b694a563670900b65d4 --- /dev/null +++ b/2023/Masked Autoencoders are Efficient Class Incremental Learners/full.md @@ -0,0 +1,372 @@ +# Masked Autoencoders are Efficient Class Incremental Learners + +Jiang-Tian Zhai $^{1}$ Xialei Liu $^{1,*}$ Andrew D. Bagdanov $^{2}$ Ke Li $^{3}$ Ming-Ming Cheng $^{1}$ VCIP, CS, Nankai University $^{2}$ MICC, University of Florence $^{3}$ Tencent Youtu Lab + +# Abstract + +Class Incremental Learning (CIL) aims to sequentially learn new classes while avoiding catastrophic forgetting of previous knowledge. We propose to use Masked Autoencoders (MAEs) as efficient learners for CIL. MAEs were originally designed to learn useful representations through reconstructive unsupervised learning, and they can be easily integrated with a supervised loss for classification. Moreover, MAEs can reliably reconstruct original input images from randomly selected patches, which we use to store exemplars from past tasks more efficiently for CIL. We also propose a bilateral MAE framework to learn from image-level and embedding-level fusion, which produces better-quality reconstructed images and more stable representations. Our experiments confirm that our approach performs better than the state-of-the-art on CIFAR-100, ImageNet-Subset, and ImageNet-Full. The code is available at https://github.com/scok30/MAE-CIL. + +# 1. Introduction + +Deep learning has had a broad and deep impact on most computer vision tasks over the last ten years. Given the way humans learn continually in their lifespan, it is natural to expect models also to be able to accumulate knowledge and build on past experiences to adapt to new tasks incrementally. The real world is very dynamic, leading to varying data distributions over time, while deep models tend to catastrophically forget old tasks when learning new ones [26]. + +Class Incremental Learning (CIL) aims to learn new classification tasks sequentially while avoiding catastrophic forgetting [2, 25]. CIL approaches can be roughly divided into three categories [5], i.e., Rehearsal-based methods [13, 29, 31], Regularization-based methods [15, 17], and Architecture-based methods [1, 23, 24]. Among them, Rehearsal-based methods achieve state-of-the-art performance by storing exemplars from past tasks or generating synthetic samples for replay. + +![](images/1e7fdd29b007c374d0bd78f9399d702c2c5fd848fe24d73c8eaf7b7bfe969c57.jpg) +Figure 1. Our proposed bilateral MAE for efficient CIL. The Replay Buffer contains random patches selected from past task images, which is more efficient than storing whole images. Combining these with masked input data from the current task, the MAE simultaneously learns to classify and reconstruct images from the masked input. To further improve the reconstructed image quality and learned representations, embedding-level and image-level fusion is used to learn more stable representations and more detailed reconstructions for CIL. + +Normally, only a fixed size of memory is allowed during incremental learning. Therefore, it limits the stored exemplars from past tasks. Other works exploit generative networks [35, 38, 43] (e.g., GANs) to synthesize samples from old tasks for replay. Although they can generate replay data to mitigate forgetting, a typical drawback is the quality of generated images, and that forgetting can also happen in generative models. In this work, we introduce Masked Autoencoders (MAEs) [11] as a base model to replay. It allows efficient exemplar storage by only requiring a small subset of patches to reconstruct whole images. Therefore, we can store more exemplars with the same amount of limited memory as other exemplar-based approaches. Compared to previous generative methods, replay by MAE is more stable because it uses partial cues to infer global information, which is task-agnostic and suffers less forgetting across tasks. This relieves the unstable generation effect of GANs across tasks with stationary image patches. + +Masked Autoencoders (MAEs) [11] were initially proposed to learn better feature representations in self-supervised learning scenarios. In this work, we see it as efficient incremental learners and propose a novel bilat + +eral transformer architecture for efficient exemplar replay in CIL. Our main idea is simple: by randomly masking patches of input images and training models to reconstruct the masked pixels, MAEs can provide a new form of self-supervised representation learning for CIL and thus learn more generalizable representations essential for CIL. In addition, leveraging a supervised objective with classification labels benefits unsupervised MAE in training efficiency and model robustness [18]. Masked inputs can also serve as strong classification regularization by only providing a random subset of data. + +When learning new tasks, the MAE can coarsely reconstruct images from sparsely sampled patches from exemplars. This process enables the framework to generate reconstructed replay data, but two problems remain: (i) the generated images tend to have less detailed and less realistic textures, which reduces data diversity for replay; and (ii) on the embedding-level, the linear classifier lacks information from low-level features. Therefore, we introduce a bilateral MAE framework with image-level and embedding-level fusion for CIL (see Fig. 1 for a schematic overview). Fusing a complementary detailed and reconstructed image alleviates catastrophic forgetting by enriching the insufficient replay data with detailed, high-quality data distributions. Embedding-level fusion from the two branches also maintains stable and diverse embeddings, and our framework can thus achieve a better trade-off between plasticity and stability. + +The main contributions of our bilateral MAE framework are threefold: + +- We introduce an MAE framework for efficient incremental learning that incorporates benefits from both self-supervised reconstruction and data generation for replay. +- To further boost the quality of reconstructed images and learning efficiency, we design a novel bilateral MAE with two complementary branches for better-reconstructed images and regularized representations. +- Our approach achieves state-of-the-art performance under different CIL settings on CIFAR-100, ImageNet-Subset, and ImageNet-Full. + +# 2. Related Work + +Incremental learning. Various methods have been proposed for incremental learning in the past few years [2, 5]. Recent works can be coarsely grouped into three categories: replay-based, regularization-based, and parameter-isolation methods. Replay-based methods mitigate the task-recency bias by replaying training samples from previous tasks. In addition to replaying samples, BiC [36], PODNet [8], and iCaRL [29] apply a distillation loss to prevent forgetting and enhance model stability. GEM [21], AGEM [3], + +and MER [30] exploit past-task exemplars by modifying gradients on current training samples to match old samples. Rehearsal-based methods may cause models to overfit stored samples. + +Pseudo-replay methods reconstruct the old data for replay. MeRGANs [35] use conditional GANs to balance the generation of old and current samples. Besides, dreamingrelevant methods like DeepInversion [41] and AlwaysBeDreaming [33] exploit backward signals to generate images similar to the original datasets. + +Regularization-based approaches, such as LwF [17], EWC [15], and DMC [44], offer methods to learn better representations while leaving enough plasticity for adaptation to new tasks. Parameter-isolation methods [24,39] use models with different computational graphs for each task. With the help of growing models, new model branches mitigate catastrophic forgetting at the cost of more parameters and computational costs. + +Self-Supervised Learning. Self-supervised learning [7, 27, 37] has been shown to help models learn generalizable features, which makes it natural to consider its application to incremental learning. Early works used pretext tasks like patch permutation [27] or rotation prediction [10]. Contrastive learning approaches model the pairwise similarity and dissimilarity between samples [4]. By comparison, MAEs [11] learn feature representations by reconstructing images from a masked version of inputs. + +There are a few works proposing self-supervision for class incremental learning. PASS [46] incorporates rotation prediction [10] to learn representations transferable across tasks. DualNet [28] uses Barlow Twins [42] to introduce a "slow" task that regularizes the "fast" incremental learning. In this paper, we explore the framework generates data for replay while applying semantic and detailed-level self-supervision, which mitigates forgetting via richer replay data and more generalizable features. + +# 3. Continual MAE for CIL + +In this section, we first define the class incremental learning problem and the basic MAE model. Then we introduce our incremental learning framework and the bilateral MAE architecture it is based on. + +# 3.1. Preliminaries + +The class incremental learning problem. CIL aims to sequentially learn tasks with new classes while preventing or alleviating forgetting of old tasks. At a specific phase of learning task $t \in \{1,2,\dots,T\}$ , model training can exploit only data from the current task $\{(x_i^t,y_i^t)\}$ , where $x_{i}^{t}$ denotes image $i$ in task $t$ and $y_{i}^{t}$ its corresponding class label. A CIL model typically consists of a feature extractor $F_{\theta}$ and a common classifier $G_{\phi}$ which grows at each new + +![](images/d7ec2e7a634a1a011c36f513c120d12d55c85f74d0f43e3f7ec574b2c7118c6b.jpg) +Figure 2. Overall framework of our bilateral MAE for CIL. The masked input is passed through two branches with embedding-level fusion for classification and image-level fusion for reconstruction. Full images can be generated from a small sample of input patches and the reconstructed images can be used as replay. + +task. At task $t + 1$ , $C_{t + 1}$ new classes are added to $G_{\phi}$ . The feature extractor $F_{\theta}$ first maps the input $x$ to a deep feature vector $z = F_{\theta}(x)\in \mathbb{R}^{d}$ , where $d$ is the dimension of the output feature representation, and then the unified classifier $G_{\phi}(z)\in \mathbb{R}^{C_{1:t}}$ produces a probability distribution over classes $C_{1:t}$ which is used to make predictions on input $x$ . + +When training task $t$ , the model aims to minimize losses on the current task without degrading performance on previous tasks. A common technique for mitigating forgetting is to retain a small buffer of training samples from previous tasks. Let $\epsilon$ be this buffer of previous task samples. One essential problem for CIL is the limited amount of replay data. Compared to the full data of current task $t$ , only a few samples of old task classes are available (20 samples per class is a common setting), which causes imbalanced training between new and old tasks. + +An MAE framework for classification. An MAE first crops input image $x$ into non-overlapping patches, and we denote the number of patches in the full image $x$ as $N_{f}$ . After patchification, the MAE randomly masks a proportion $r \in [0,1]$ of the $N_{f}$ patches, leaving only $N = \lfloor N_{f} \times (1 - r) \rfloor$ patches. Then these sampled $K \times K$ pixel patches are mapped to a visual embedding of dimension $D$ using an MLP. After concatenating with a class token, the result is a tensor of size $\mathbb{R}^{(N + 1) \times D}$ . After positionally encoding the original patch locations, this input is passed to the MAE transformer encoder. This operation maintains the same shape of embedding. The output class token embedding can be used for classification with a cross-entropy loss $\mathcal{L}_t^{\mathrm{cls}}$ , as shown in Fig. 2. + +For the MAE Decoder, learnable mask tokens are inserted into the embeddings in place of the masked patches, and the shape of output from the MAE Encoder changes + +from $\mathbb{R}^{(N + 1)\times D}$ to $\mathbb{R}^{(N_f + 1)\times D}$ . Although the decoder is not used for classification, it helps the network backpropagate image-level reconstruction supervision to the embedding-level. This stabilizes the image embedding and helps the optimization process. Also, the reconstructed images after decoding provide richer, higher-quality replay data. To limit computation, we use a single-layer transformer block for the decoder. The additional classification loss after the encoder speeds up convergence and improves reconstruction efficiency during training. The mean squared error between the input image $x$ and reconstructed image $\hat{x}$ is used as the reconstruction loss function $\mathcal{L}_t^{\mathrm{rec}}(x,\hat{x})$ . + +# 3.2. Efficient Exemplar Storage with MAEs + +After training each task, we save small sample images and apply random masking. Keeping the same storage size can save more replay data per class since each sample occupies less space. For example, a masking ratio of 0.75 allows us to save $4 \times$ the number of (reconstructible) samples compared to conventional replay methods. + +Let $S$ and $P$ denote the size of the image and patch, respectively. Our encoder patchifies the input image into $\frac{S}{P} \times \frac{S}{P}$ patches. We save the 2D index $(i,j)$ for each patch that is not masked. We need only one byte to save these indexes since their range is less than 255. The two additional bytes for saving this 2D index are negligible compared to the saved image patches. A masking ratio 0.75 on a $224 \times 224$ image requires only 36.75KB of storage. For $P = 16$ , the number of saved patches is $(1 - 0.75) \times (\frac{224}{16})^2 = 49$ , and the storage of indexes is only 98B. + +# 3.3. Bilateral MAE Fusion + +To further boost reconstruction quality and embedding diversity, we propose a two-branches MAE to learn global + +![](images/8821003216817f7bb3843edc8f8423a18f766d1c82319b99994a21d92b7d6063.jpg) +Figure 3. An example of extracting detailed images with reconstructed results from different masking ratios $r_1$ and $r_2$ . The third image comes from the difference between the previous two, and the last image is the extracted high-frequency component from the third image. + +Algorithm 1 Pseudocode of our Bilateral MAE. +```latex +Input: The number of task $T$ , training samples $D_{t} = \{(x_{i},y_{i})\}_{t}$ of task $t$ , model $\Theta^0$ , replay buffer $\epsilon$ , and masking ratios $r, r_1, r_2$ . +``` + +Output: model $\Theta^T$ +```txt +1: for $t \in \{1, 2, \dots, T\}$ do +``` + +```txt +2: $\Theta^t\gets \Theta^{t - 1}$ +``` + +```javascript +3: $R_{t}\gets \mathrm{ReconstructOldSamples}(\epsilon_{t},r)$ +``` + +```txt +4: while not converged do +``` + +```javascript +5: $(x,y)\gets$ Sample $(R_{t},D_{t})$ +``` + +```txt +6: $(\mathcal{L}_t^{\mathrm{cls}},\mathcal{L}_t^{\mathrm{rec}})\gets$ BilateralMAE $(x,y)$ +``` + +```latex +7: $(\hat{x}_1, \hat{x}_2) \gets \text{MaskAndReconstruct}(x, r_1, r_2)$ +``` + +```txt +8: $\mathcal{L}_t^{\mathrm{det}}\gets$ ComputeDetailLoss $(\hat{x}_1,\hat{x}_2)$ +``` + +```txt +9: train $\Theta^t$ by minimizing $\mathcal{L}_t$ from Eq. 12 +``` + +```txt +10: end while +``` + +```txt +11: end for +``` + +and detailed classification and image reconstruction knowledge. We illustrate the overall framework in Fig. 2. Bilateral fusion at the embedding-level aims to improve representations diversity. Reconstruction learning at the image-level yields high-quality replay data and stable self-supervision for CIL. + +Embedding fusion. In the following we use $F_{\theta[:1]}$ and $F_{\theta[1:]}$ to denote our transformer encoder's first and following blocks. Let $H_{\theta}$ and $E_{\theta}$ represent the detailed block and embedding fusion module in Fig. 2, which are standard MLP layers and attention blocks, respectively. The classification loss is computed as: + +$$ +f = F _ {\theta [: 1 ]} (\operatorname {m a s k} (x, r)) \tag {1} +$$ + +$$ +z = E _ {\theta} \left(F _ {\theta [ 1: ]} (f), H _ {\theta} (f)\right) \tag {2} +$$ + +$$ +\mathcal {L} _ {t} ^ {\mathrm {c l s}} (x, y) = \mathcal {L} _ {\mathrm {c e}} \left(G _ {\phi} (z), y\right), \tag {3} +$$ + +where $\mathrm{mask}(x,r)$ denotes applying random masking with ratio $r$ on image $x$ , $f$ is the embedding extracted by the first encoder block, which is the input to the two branches of our Bilateral MAE, and $G_{\phi}(z)$ is the estimated class distribution used for in the cross entropy loss. + +Image fusion with detailed loss. For the detailed head and corresponding loss, we discovered that working in the frequency domain makes it easier for the network to attend to high-frequency details, which is exactly what the detailed branch should reconstruct. We define a frequency-masking function $M(\cdot)$ that converts its argument (an image patch) to the frequency domain, then masks out low frequencies using a circular mask around the origin. As shown in Fig. 2, the MAE decoder is shared by the two branches of our model since they have similar reconstruction tasks, as well as input and output shapes. Let $D_{\theta}$ be this shared decoder, then the image-level outputs of the two branches and the reconstruction loss $\mathcal{L}_t^{\mathrm{rec}}$ are: + +$$ +f = F _ {\theta [: 1 ]} (\operatorname {m a s k} (x, r)) \tag {4} +$$ + +$$ +x ^ {\prime} = D _ {\theta} \left(F _ {\theta [ 1: ]} (f)\right) \tag {5} +$$ + +$$ +x ^ {\prime \prime} = \text {i f t 2} \left(M \left(D _ {\theta} \left(H _ {\theta} (f)\right)\right)\right) \tag {6} +$$ + +$$ +\hat {x} = x ^ {\prime} + x ^ {\prime \prime} \tag {7} +$$ + +$$ +\mathcal {L} _ {t} ^ {\text {r e c}} = \mathcal {L} _ {\text {m s e}} (x, \hat {x}), \tag {8} +$$ + +where $x'$ and $x''$ are the main and residual detailed outputs, respectively, and ifft2 is the inverse Fast Fourier Transform. + +The detailed loss $\mathcal{L}_t^{\mathrm{det}}$ also makes use of the frequencymasking function $M$ to compare the output of the detailed branch and the difference between two MAE reconstructions of the input image: + +$$ +\hat {x} _ {1} = D _ {\theta} \left(F _ {\theta} \left(\operatorname {m a s k} \left(x, r _ {1}\right)\right)\right) \tag {9} +$$ + +$$ +\hat {x} _ {2} = D _ {\theta} \left(F _ {\theta} (\operatorname {m a s k} (x, r _ {2}))\right) \tag {10} +$$ + +$$ +\mathcal {L} _ {t} ^ {\mathrm {d e t}} = | | M \left(D _ {\theta} \left(H _ {\theta} (f)\right) - M \left(\hat {x} _ {2} - \hat {x} _ {1}\right) \right| | _ {1}, \tag {11} +$$ + +where $\hat{x}_1$ and $\hat{x}_2$ are two reconstructed images (detached from the gradient computation graph) using different masking ratios $r_1$ and $r_2$ , respectively. The residual difference $\hat{x}_2 - \hat{x}_1$ is used as supervision in the frequency domain for the detailed branch in loss $\mathcal{L}_t^{\mathrm{det}}$ . An illustration can be found in Fig. 3. + +A weighted sum of classification loss $\mathcal{L}_t^{\mathrm{cls}}$ , reconstruction loss $\mathcal{L}_t^{\mathrm{rec}}$ , and detail loss $\mathcal{L}_t^{\mathrm{det}}$ is used as the overall loss for training: + +$$ +\mathcal {L} _ {t} = \lambda_ {\mathrm {c l s}} \mathcal {L} _ {t} ^ {\mathrm {c l s}} + \lambda_ {\mathrm {r e c}} \mathcal {L} _ {t} ^ {\mathrm {r e c}} + \lambda_ {\mathrm {d e t}} \mathcal {L} _ {t} ^ {\mathrm {d e t}}. \tag {12} +$$ + +Pseudocode for our method is given in Algorithm 1. + +# 4. Experimental Results + +# 4.1. Benchmarks and Implementation + +Datasets and settings. We experiment on three datasets: CIFAR-100 [16], ImageNet-Subset, and ImageNet-Full [6] to evaluate the performance of our approach. For CIFAR-100 and ImageNet-Subset, we test on 10-, 20- and 50-task scenarios, all with equal numbers of classes per task. We + +![](images/bcf872f93dee9c777892de3c804c9e49d4c2abab9dd7f64153954d0526cc9dfa.jpg) +Figure 4. Performance evolution over incremental tasks on CIFAR-100 on 10-, 20- and 50-task scenarios. + +![](images/8fe608cc81c9ed84b0c7530029041ac67aafb95127a0752dbf0ba1a914d2e830.jpg) + +![](images/a1b493e45cafadc068437d8be0b74033bb4b91d9e0328768730939e0564160e9.jpg) + +
MethodN=10N=20N=50
Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓
iCaRL [29]65.2750.7431.2361.2043.7532.4056.0836.6236.59
UCIR [12]58.6643.3935.6758.1740.6337.7556.8637.0938.13
BiC [36]68.8053.5428.4466.4847.0229.3062.0941.0434.27
PODNet [8]58.0341.0541.4753.9735.0236.7051.1932.9940.42
DER w/o P [40]75.3665.2215.0274.0962.4823.5572.4159.0826.73
DER [40]74.6464.3515.7873.9862.5523.4772.0559.7626.59
DyTox [9]75.4762.1015.4375.1059.4121.6073.8957.2124.22
Ours79.1268.4012.1778.7665.2214.3976.9563.1218.34
+ +Table 1. Results on CIFAR-100 in average accuracy (%), last phase accuracy (%), and forgetting F (% on 10-, 20- and 50-task scenarios. + +evaluate the 10-task setting for ImageNet-Full in which 100 new classes are included in each task. To measure the overall accuracy after all tasks during training, we report the average accuracy of learned tasks after each task and the accuracy of all tasks at the end of incremental learning. + +Implementation details. We use the same network for all datasets. Models are trained from scratch to prevent data leakage with batch size of 1024 using Adam [14] with initial learning rate 1e-4 and cosine decay. The loss weights from Eq. 12 are set to $\lambda_{cls} = 0.01$ , $\lambda_{rec} = 1.0$ and $\lambda_{det} = 1.0$ . The masking ratios are set to $r = 0.75$ , $r_1 = 0.75$ , and $r_2 = 0.4$ . Each task is trained for 400 epochs. For exemplar-based methods from the literature, we store 20 samples for each classes (as is common practice). + +We use 5 transformer blocks for the encoder and 1 for the decoder. All transformer blocks have an embedding dimension of 384 and 12 self-attention heads. This design differs from the original MAE as it is much more lightweight. We save image patches occupying the same amount of memory as other methods which store 20 full images per class. For example, we select 80 images and randomly save only $25\%$ patches from each using a masking ratio of 0.75 (thus only occupying the same space as 20 whole images). The detailed block is implemented with a 3-layer MLP keeping the dimension at 384. Further details about network architecture are given in the Supplementary Material. + +# 4.2. Comparison with the state-of-the-art + +In this section we compare our approach with the state-of-the-art, including DER [40] and DyTox [9]. In all plots and tables, "DER w/o P" denotes DER [40] without pruning, therefore leading to more parameters being added across tasks. DyTox [9] also uses a transformer architecture and we use the official codebase to reproduce its results. + +CIFAR-100. We report results in average accuracy (Avg), the accuracy after the last task (Last), and average forgetting (F) in Table 1. It is clear that under each setting our method outperforms others by a large margin. For longer task sequences, our bilateral MAE benefits from self-supervised reconstruction and richer replay data and it forgets much less compared to other methods. An overall accuracy curve is given in Fig. 4. Using the same amount of replay storage, our method outperforms DyTox by about $6\%$ in accuracy after the last task in all three scenarios. + +ImageNet-Subset and ImageNet-Full. We report performance on ImageNet-Subset and ImageNet-Full in Tables 2 and 3, respectively. Our method outperforms DyTox [9] by $1.19\%$ , $2.53\%$ , and $2.85\%$ absolute gain in accuracy after the last task on the 10-, 20- and 50-task settings, respectively. The higher average accuracy during each phase and lower forgetting also demonstrates the effectiveness of our method in alleviating forgetting. We also + +![](images/8c43506805450191905fa3f0de49425a1f2d646825d336d0ea5cf76bf90a5a60.jpg) +Figure 5. Performance evolution over incremental tasks on ImageNet-Subset. + +![](images/237955116686f7b99a4bc37a0236ed4dd601132ccdfd27eb2002c69f86f616ec.jpg) + +![](images/a5efb5db626293b21b504615bccc1b091c4166aabd8dd45d6325c4132ab96a7f.jpg) + +
MethodN=10N=20N=50
Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓
BiC [36]64.9655.0731.3259.4049.3534.7053.7544.5640.23
PODNet [8]63.4451.7535.6355.1145.3741.7051.7242.9444.65
DER w/o P [40]77.1866.7014.8672.7061.7420.7670.4458.8724.20
DER [40]76.1266.0615.0972.5661.5120.4669.7758.1925.35
DyTox [9]77.1569.1014.6673.1361.8717.3271.5160.0220.54
Ours79.5470.2912.0475.2064.4014.8974.4262.8717.22
+ +Table 2. Results on ImageNet-Subset in average and last phase accuracy (%) and forgetting rate F (%) on 10-, 20- and 50-task scenarios. + +
Methodtop-1top-5
Avg ↑Last ↑Avg ↑Last ↑
iCaRL [29]38.4022.7063.7044.00
Simple-DER66.6359.2485.6280.76
DER w/o P [40]68.8460.1688.1782.86
DER [40]66.7358.6287.0881.89
DyTox [9]71.2963.3488.5984.49
Ours74.7666.1591.4387.13
+ +illustrate the performance evolution on ImageNet-Subset in Fig. 5. Our method has accuracy similar to DyTox in the first task, but in later tasks our method surpasses all others, especially for long task sequences. On the larger-scale ImageNet-Full, our Bilateral MAE significantly outperforms other methods by about $3\%$ in all metrics. + +# 4.3. Ablation Study + +Ablations on different components. Our bilateral MAE consists of a self-supervised reconstruction task, generated data for replay, and a bilateral MAE branch for image- and embedding-level fusion. We ablate on these three factors in Table 4. These three major components in our method have different functions and they cooperate to boost performance compared with the baseline by about $6\%$ . We observe that: (a) More high-quality replay data has a direct contribution to the performance and masking ration of $r = 0.75$ masking ratio yields $4 \times$ replay for the same storage cost as the + +Table 3. Results on ImageNet-Full for 10 incremental tasks. + +
MethodReplayReconstructionBilateralAvgLast
Baseline73.4062.31
Variants✓75.8864.35
✓✓77.4866.54
✓✓✓79.1268.40
+ +Table 4. Ablative experiments on each component of our proposed method in the 10-task setting on CIFAR-100. Replay denotes using generated data from MAE for replay, Reconstruction means applying the self-supervised reconstruction loss, and Bilateral indicates introduction the detailed branch of the MAE. + +
rData SourceAvgLast
0.60Generated77.5067.37
0.75Generated79.1268.40
0.90Generated77.1267.02
N/AReal79.5768.87
+ +Table 5. Ablation on the masking ratio and quality of generated data. Experiments are on CIFAR-100 in the 10-task setting and we report top-1 accuracy in %. Data Source indicates whether replay is generated or real. In the last row we replay a selection of of real images equivalent in storage size to using $r_1 = 0.75$ . + +baseline. (b) The reconstruction loss serves as effective self-supervision and improves performance by about $2\%$ in average accuracy. (c) The bilateral architecture works well by improving replay data generation quality and introducing image and embedding-level supervision. + +
DomainAvgLast
Spatial77.4565.93
Frequency79.1268.40
+ +Table 6. Ablative experiments on the detailed head. Experiments are on CIFAR-100 in the 10-task setting and we report the top-1 accuracy in $\%$ . Domain denotes to which domain our loss is applied. + +![](images/fb7984d0f1b1d796a542cf6f2a72e951542fbace7c680a45ba54885eaa46427f.jpg) +Figure 6. Ablation on masking ratio $r_2$ in $\mathcal{L}_t^{\mathrm{det}}$ . The other masking ratio $r_1$ is set to $75\%$ as the reference. + +Masking ratio. A key parameter of MAE [11] is the masking ratio $r$ . There is trade-off on $r$ : too large $r$ (e.g. 0.95) leads to poor reconstruction, which influences the quality of replay data and causes more serious forgetting. However, too small $r$ yields a limited extra amount of replay data (e.g. we can afford only about $11\%$ extra replay data when $r$ is 0.10). The results in Table 5 show that $r = 0.75$ is a good trade-off for our bilateral MAE. To verify the quality of generated data for replay, also include results using original images for replay in place of generated ones. Results in rows 2 and 4 of Table 5 show that our method achieves good quality images with less than $0.5\%$ accuracy difference compared to replaying real images. + +Frequency domain for the detailed loss. We implemented the detailed loss by converting embeddings from the spatial domain to the frequency domain. This aims to allow concentration on high-frequency information which matches the learning objective of the detailed MAE branch. As shown in Table 6, it is beneficial to make this conversion as it leads to a more than $2\%$ gain at the last task. + +Ablation on $r_1$ and $r_2$ in the detailed loss. We set $r_1$ to 0.75 for all these experiments as a reference and we vary $r_2$ used for computing the ground truth of the detailed loss. The trade-off on $r_2$ is that large $r_2$ results in small differences between the reconstructed results from mask ratios $r_1$ and $r_2$ and therefore there is little information in the supervisory signal for the detailed loss and the impact of the detailed branch is reduced. On the other hand, too small + +
MethodParameters (M)Avg ↑Last ↑F ↓
DER w/o P112.2775.3665.2215.02
DyTox10.7375.4762.1015.43
Ours (MLP size = 1536)12.8979.1268.4012.17
Ours (MLP size = 768)9.3578.3667.5212.90
+ +Table 7. Comparison of model sizes. We compare two versions of our Bilateral MAE and competing models. Experiments were conducted on CIFAR-100 with 10 tasks. + +$r_2$ (e.g. 0.10) maintains most of the residual part of reconstructed images from the main branch, which may bring weak supervision for the main branch and slow its training. We show results for a range of $r_2$ values in Fig. 6. These results show that an $r_2$ of about 0.40 is good for providing supervision to the detailed branch of our MAE. + +Model and exemplar sizes. To compare the effectiveness of different methods, normally models with the same or similar number of parameters are used with an equal number of exemplars. In our approach, we adapt the original MAE to be more lightweight and the number of parameters is comparable to or even smaller than DyTox, as shown in Table 7 (last row). We set the masking ratio to $75\%$ by default and save 80 exemplars per class, and therefore the storage size for both models and exemplars is similar since our stored image patches require exactly the same as baselines using only 20 exemplars. + +Ablation on effective buffer size. In Table 8 we compare our method with Dytox using the same buffer size by masking input image patches in input to DyTox. All three rows use the same memory size for storing exemplars. Using 80 exemplars with masking ratio of $75\%$ , DyTox (last row) achieves better performance than when using 20 full-image exemplars. It still performs worse than our approach, which shows that our performance gain does not simply come from the additional exemplars, but also from the integration of the MAE into our bilateral architecture with the Detailed Branch. + +Reconstruction analysis. We illustrate results of image reconstruction in the 10-task setting on ImageNet-Subset in Fig. 7. Randomly selected images from tasks 1, 4, 7, and 10 are shown in the left column. Our bilateral MAE learns to reconstruct images in a task-agnostic way, which helps generate reasonable results for future tasks even before learning them. The detailed branch of our MAE learns to reconstruct high-frequency details complementary to the main branch. The results from the main branch sometimes lack sample-specific characteristics, but with the help of our proposed detailed branch the reconstructions are more accurate and provide better generated replay data. + +![](images/f675e55d9fe3a6e651045cf1210cdb24658bd690f4ef0c02952566650db44d49.jpg) +Image + +![](images/65f60aeb255c7e0db0f32b7cef9073a7973463390543321387062664a20b02ae.jpg) +Task 1 + +![](images/193eca8f004189599fb6abbb5a0f02d15a3b91d93cdc5026f096319542fb6f8e.jpg) +Task 4 +Figure 7. Reconstructed images from ImageNet-Subset in the 10-task setting. Four original images were selected from tasks 1, 4, 6, and 10 and are shown on the left. In the remaining columns we show reconstructed images using our combined Bilateral MAE (left), only the detailed branch of our MAE (middle), and only the main branch of our MAE (right). + +![](images/1f6ca61ea5470c0ed2b64db7413117da6ad32c2b92733cbe375b5e03332f9574.jpg) +Task 7 + +![](images/4f90a44ff2b2e59a0a65e4282a3f2fcc955b971c9f8c02588fda54fde540918d.jpg) +Task 10 + +
MethodBufferMemory size25% PatchesImagesAcc(%)
Ours801x✓68.40
DyTox201x✓62.10
DyToxt801x✓65.46
+ +Table 8. Ablation on effective buffer size with equal memory usage. Dytox† represents applying a mask ratio $r = 75\%$ directly to stored image exemplars in order to have the same number of exemplars and storage size for DyTox as in our setting. + +![](images/ed239fd20b7b53c839b8407fbdc3c4616a1fcfa81bd80bcbe5c1d4637aa71df5.jpg) +Figure 8. Comparison of feature space density $\pi$ . + +More generalizable representations help CIL. We calculated the feature space density metric [32] for different methods following PASS [46]: $\pi = \pi_{intra} / \pi_{inter}$ , where $\pi_{intra}$ denotes the average cosine similarity within the same class and $\pi_{inter}$ denotes the one within different classes. Increased feature space density is associated with stronger generalization under data shift [46]. We then compared feature space density after training all tasks, as shown in Figure 8 above. It is clear that Ours yields significantly higher density than other methods. + +Ablation with other efficient replay methods. We compared the replay samples generated by MAE in our framework with a variety of memory-efficient methods based on latent replay [19], synthesized exemplars [20], down- + +
MetricMemoryAvg↑Last↑
Latent replay (CVPRW'20) [19]-62.4451.30
MCIL (CVPR'20) [20]6063.2553.12
Down-scaled (TNNLS'21) [45]6067.0455.40
JPEG compression (ICLR'22) [34]6072.3461.32
CIM (CVPR'23) [22]6075.3063.05
Ours6079.1268.40
+ +Table 9. Comparison of our bilateral MAE framework with other memory-efficient methods on the CIFAR-100 10-task setting. Memory indicates the required storage space per class (in KB). + +scaling [45], JPEG image compression [34], and CIM [22] (foreground extraction and background compression). All these methods use the same amount of storage (except Latent Replay uses a GAN with 4.5M parameters), while our approach achieves consistently higher performance. + +# 5. Conclusions + +In this work, we demonstrate that Masked Autoencoders are efficient incremental learners. Our approach stores random image patches as exemplars and it can reconstruct high-quality images from only partial information for replay. Furthermore, we propose a novel bilateral MAE architecture which further improves embedding diversity and reconstruction quality. Our Bilateral MAE approach significantly outperforms previous state-of-the-art methods for the same exemplar storage cost. + +Acknowledgements This work is funded by NSFC (NO. 62225604, 62206135), and the Fundamental Research Funds for the Central Universities (Nankai University, 070-63233085). Computation is supported by the Supercomputing Center of Nankai University. + +# References + +[1] Rahaf Aljundi, Punarjay Chakravarty, and Tinne Tuytelaars. Expert gate: Lifelong learning with a network of experts. In IEEE Conf. Comput. Vis. Pattern Recog., 2017. 1 +[2] Eden Belouadah, Adrian Popescu, and Ioannis Kanellos. A comprehensive study of class incremental learning algorithms for visual tasks. Neural Networks, 135:38-54, 2021. 1, 2 +[3] Arslan Chaudhry, Marc'Aurelio Ranzato, Marcus Rohrbach, and Mohamed Elhoseiny. Efficient lifelong learning with a gem. In Int. Conf. Learn. Represent., 2019. 2 +[4] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning of visual representations. In International conference on machine learning, pages 1597-1607. PMLR, 2020. 2 +[5] Matthias Delange, Rahaf Aljundi, Marc Masana, Sarah Parisot, Xu Jia, Ales Leonardis, Greg Slabaugh, and Tinne Tuytelaars. A continual learning survey: Defying forgetting in classification tasks. TPAMI, 2021. 1, 2 +[6] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In IEEE Conf. Comput. Vis. Pattern Recog., 2009. 4 +[7] Carl Doersch, Abhinav Gupta, and Alexei A Efros. Unsupervised visual representation learning by context prediction. In Int. Conf. Comput. Vis., 2015. 2 +[8] Arthur Douillard, Matthieu Cord, Charles Ollion, Thomas Robert, and Eduardo Valle. Podnet: Pooled outputs distillation for small-tasks incremental learning. In Eur. Conf. Comput. Vis., 2020. 2, 5, 6 +[9] Arthur Douillard, Alexandre Rame, Guillaume Couairon, and Matthieu Cord. Dytox: Transformers for continual learning with dynamic token expansion. In IEEE Conf. Comput. Vis. Pattern Recog., 2022. 5, 6 +[10] Spyros Gidaris, Praveer Singh, and Nikos Komodakis. Unsupervised representation learning by predicting image rotations. In Int. Conf. Learn. Represent., 2018. 2 +[11] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In IEEE Conf. Comput. Vis. Pattern Recog., 2022. 1, 2, 7 +[12] Saihui Hou, Xinyu Pan, Chen Change Loy, Zilei Wang, and Dahua Lin. Learning a unified classifier incrementally via rebalancing. In IEEE Conf. Comput. Vis. Pattern Recog., 2019. 5 +[13] David Isele and Akansel Cosgun. Selective experience replay for lifelong learning. In AAAI, 2018. 1 +[14] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. In Int. Conf. Learn. Represent., 2015. 5 +[15] James Kirkpatrick, Razvan Pascanu, Neil Rabinowitz, Joel Veness, Guillaume Desjardins, Andrei A Rusu, Kieran Milan, John Quan, Tiago Ramalho, Agnieszka Grabska-Barwinska, et al. Overcoming catastrophic forgetting in neural networks. Proceedings of the national academy of sciences, 2017. 1, 2 + +[16] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images, 2009. 4 +[17] Zhizhong Li and Derek Hoiem. Learning without forgetting. In Eur. Conf. Comput. Vis., 2016. 1, 2 +[18] Feng Liang, Yangguang Li, and Diana Marculescu. Supmae: Supervised masked autoencoders are efficient vision learners. arXiv preprint arXiv:2205.14540, 2022. 2 +[19] Xialei Liu, Chenshen Wu, Mikel Menta, Luis Herranz, Bogdan Raducanu, Andrew D Bagdanov, Shangling Jui, and Joost van de Weijer. Generative feature replay for class incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog. Worksh., 2020. 8 +[20] Yaoyao Liu, Yuting Su, An-An Liu, Bernt Schiele, and Qianru Sun. Mnemonics training: Multi-class incremental learning without forgetting. In IEEE Conf. Comput. Vis. Pattern Recog., pages 12245-12254, 2020. 8 +[21] David Lopez-Paz and Marc'Aurelio Ranzato. Gradient episodic memory for continual learning. Adv. Neural Inform. Process. Syst., 2017. 2 +[22] Zilin Luo, Yaoyao Liu, Bernt Schiele, and Qianru Sun. Class-incremental exemplar compression for class-incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., pages 11371-11380, 2023. 8 +[23] Arun Mallya, Dillon Davis, and Svetlana Lazebnik. Piggyback: Adapting a single network to multiple tasks by learning to mask weights. In Eur. Conf. Comput. Vis., 2018. 1 +[24] Arun Mallya and Svetlana Lazebnik. Packnet: Adding multiple tasks to a single network by iterative pruning. In IEEE Conf. Comput. Vis. Pattern Recog., 2018. 1, 2 +[25] Marc Masana, Xialei Liu, Barttomiej Twardowski, Mikel Menta, Andrew D. Bagdanov, and Joost van de Weijer. Class-incremental learning: Survey and performance evaluation on image classification. IEEE Trans. Pattern Anal. Mach. Intell., 2022. 1 +[26] Michael McCloskey and Neal J Cohen. Catastrophic interference in connectionist networks: The sequential learning problem. In *Psychology of learning and motivation*. Elsevier, 1989. 1 +[27] Mehdi Noroozi and Paolo Favaro. Unsupervised learning of visual representations by solving jigsaw puzzles. In Eur. Conf. Comput. Vis., 2016. 2 +[28] Quang Pham, Chenghao Liu, and Steven Hoi. Dualnet: Continual learning, fast and slow. Adv. Neural Inform. Process. Syst., 2021. 2 +[29] Sylvestre-Alvise Rebuffi, Alexander Kolesnikov, Georg Sperl, and Christoph H Lampert. icarl: Incremental classifier and representation learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2017. 1, 2, 5, 6 +[30] Matthew Riemer, Ignacio Cases, Robert Ajemian, Miao Liu, Irina Rish, Yuhai Tu, and Gerald Tesauro. Learning to learn without forgetting by maximizing transfer and minimizing interference. In Int. Conf. Learn. Represent., 2019. 2 +[31] David Rolnick, Arun Ahuja, Jonathan Schwarz, Timothy Lillicrap, and Gregory Wayne. Experience replay for continual learning. Adv. Neural Inform. Process. Syst., 2019. 1 +[32] Karsten Roth, Timo Milbich, Samarth Sinha, Prateek Gupta, Bjorn Ommer, and Joseph Paul Cohen. Revisiting training strategies and generalization performance in deep metric + +learning. In Int. Mach. Learn., pages 8242-8252. PMLR, 2020. 8 +[33] James Smith, Yen-Chang Hsu, Jonathan Balloch, Yilin Shen, Hongxia Jin, and Zsolt Kira. Always be dreaming: A new approach for data-free class-incremental learning. In Int. Conf. Comput. Vis., 2021. 2 +[34] Liyuan Wang, Xingxing Zhang, Kuo Yang, Longhui Yu, Chongxuan Li, Lanqing Hong, Shifeng Zhang, Zhenguo Li, Yi Zhong, and Jun Zhu. Memory replay with data compression for continual learning. In Int. Conf. Learn. Represent., 2022. 8 +[35] Chenshen Wu, Luis Herranz, Xialei Liu, Joost van de Weijer, Bogdan Raducanu, et al. Memory replay gans: Learning to generate new categories without forgetting. Adv. Neural Inform. Process. Syst., 2018. 1, 2 +[36] Yue Wu, Yinpeng Chen, Lijuan Wang, Yuancheng Ye, Zicheng Liu, Yandong Guo, and Yun Fu. Large scale incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2019. 2, 5, 6 +[37] Zhirong Wu, Yuanjun Xiong, Stella X Yu, and Dahua Lin. Unsupervised feature learning via non-parametric instance discrimination. In IEEE Conf. Comput. Vis. Pattern Recog., 2018. 2 +[38] Ye Xiang, Ying Fu, Pan Ji, and Hua Huang. Incremental learning using conditional adversarial networks. In Int. Conf. Comput. Vis., 2019. 1 +[39] Ju Xu and Zhanxing Zhu. Reinforced continual learning. Adv. Neural Inform. Process. Syst., 2018. 2 +[40] Shipeng Yan, Jiangwei Xie, and Xuming He. Der: Dynamically expandable representation for class incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2021. 5, 6 +[41] Hongxu Yin, Pavlo Molchanov, Jose M Alvarez, Zhizhong Li, Arun Mallya, Derek Hoiem, Niraj K Jha, and Jan Kautz. Dreaming to distill: Data-free knowledge transfer via deep-inversion. In IEEE Conf. Comput. Vis. Pattern Recog., 2020. 2 +[42] Jure Zbontar, Li Jing, Ishan Misra, Yann LeCun, and Stéphane Deny. Barlow twins: Self-supervised learning via redundancy reduction. In International Conference on Machine Learning, pages 12310-12320. PMLR, 2021. 2 +[43] Mengyao Zhai, Lei Chen, Frederick Tung, Jiawei He, Megha Nawhal, and Greg Mori. Lifelong gan: Continual learning for conditional image generation. In Int. Conf. Comput. Vis., 2019. 1 +[44] Junting Zhang, Jie Zhang, Shalini Ghosh, Dawei Li, Serafettin Tasci, Larry Heck, Heming Zhang, and C-C Jay Kuo. Class-incremental learning via deep model consolidation. In WACV, 2020. 2 +[45] Hanbin Zhao, Hui Wang, Yongjian Fu, Fei Wu, and Xi Li. Memory-efficient class-incremental learning for image classification. TNNLS, 33(10):5966-5977, 2021. 8 +[46] Fei Zhu, Xu-Yao Zhang, Chuang Wang, Fei Yin, and ChengLin Liu. Prototype augmentation and self-supervision for incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2021. 2, 8 \ No newline at end of file diff --git a/2023/Masked Autoencoders are Efficient Class Incremental Learners/images.zip b/2023/Masked Autoencoders are Efficient Class Incremental Learners/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..f4e0c4f878137a2996b1fa0bc07adc1b557c190e --- /dev/null +++ b/2023/Masked Autoencoders are Efficient Class Incremental Learners/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:7e3729c6645958ddb90bd50e047f29009e03f31ebaa4d1ebc2b62b86a3ffad96 +size 622356 diff --git a/2023/Masked Autoencoders are Efficient Class Incremental Learners/layout.json b/2023/Masked Autoencoders are Efficient Class Incremental Learners/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..a664a8a106068c67681cbb9b2bd40a62e7aff8b7 --- /dev/null +++ b/2023/Masked Autoencoders are Efficient Class Incremental Learners/layout.json @@ -0,0 +1,10299 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 100, + 103, + 493, + 119 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 100, + 103, + 493, + 119 + ], + "spans": [ + { + "bbox": [ + 100, + 103, + 493, + 119 + ], + "type": "text", + "content": "Masked Autoencoders are Efficient Class Incremental Learners" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "spans": [ + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "text", + "content": "Jiang-Tian Zhai " + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "text", + "content": " Xialei Liu " + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "inline_equation", + "content": "^{1,*}" + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "text", + "content": " Andrew D. Bagdanov " + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "text", + "content": " Ke Li " + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "text", + "content": " Ming-Ming Cheng " + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "text", + "content": " VCIP, CS, Nankai University " + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "text", + "content": " MICC, University of Florence " + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 71, + 142, + 520, + 172 + ], + "type": "text", + "content": " Tencent Youtu Lab" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 199, + 192, + 211 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 199, + 192, + 211 + ], + "spans": [ + { + "bbox": [ + 143, + 199, + 192, + 211 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 224, + 290, + 428 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 224, + 290, + 428 + ], + "spans": [ + { + "bbox": [ + 46, + 224, + 290, + 428 + ], + "type": "text", + "content": "Class Incremental Learning (CIL) aims to sequentially learn new classes while avoiding catastrophic forgetting of previous knowledge. We propose to use Masked Autoencoders (MAEs) as efficient learners for CIL. MAEs were originally designed to learn useful representations through reconstructive unsupervised learning, and they can be easily integrated with a supervised loss for classification. Moreover, MAEs can reliably reconstruct original input images from randomly selected patches, which we use to store exemplars from past tasks more efficiently for CIL. We also propose a bilateral MAE framework to learn from image-level and embedding-level fusion, which produces better-quality reconstructed images and more stable representations. Our experiments confirm that our approach performs better than the state-of-the-art on CIFAR-100, ImageNet-Subset, and ImageNet-Full. The code is available at https://github.com/scok30/MAE-CIL." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 460, + 128, + 474 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 460, + 128, + 474 + ], + "spans": [ + { + "bbox": [ + 47, + 460, + 128, + 474 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 481, + 287, + 589 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 481, + 287, + 589 + ], + "spans": [ + { + "bbox": [ + 46, + 481, + 287, + 589 + ], + "type": "text", + "content": "Deep learning has had a broad and deep impact on most computer vision tasks over the last ten years. Given the way humans learn continually in their lifespan, it is natural to expect models also to be able to accumulate knowledge and build on past experiences to adapt to new tasks incrementally. The real world is very dynamic, leading to varying data distributions over time, while deep models tend to catastrophically forget old tasks when learning new ones [26]." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 589, + 288, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 589, + 288, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 589, + 288, + 696 + ], + "type": "text", + "content": "Class Incremental Learning (CIL) aims to learn new classification tasks sequentially while avoiding catastrophic forgetting [2, 25]. CIL approaches can be roughly divided into three categories [5], i.e., Rehearsal-based methods [13, 29, 31], Regularization-based methods [15, 17], and Architecture-based methods [1, 23, 24]. Among them, Rehearsal-based methods achieve state-of-the-art performance by storing exemplars from past tasks or generating synthetic samples for replay." + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 307, + 197, + 547, + 329 + ], + "blocks": [ + { + "bbox": [ + 307, + 197, + 547, + 329 + ], + "lines": [ + { + "bbox": [ + 307, + 197, + 547, + 329 + ], + "spans": [ + { + "bbox": [ + 307, + 197, + 547, + 329 + ], + "type": "image", + "image_path": "1e7fdd29b007c374d0bd78f9399d702c2c5fd848fe24d73c8eaf7b7bfe969c57.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 330, + 547, + 429 + ], + "lines": [ + { + "bbox": [ + 304, + 330, + 547, + 429 + ], + "spans": [ + { + "bbox": [ + 304, + 330, + 547, + 429 + ], + "type": "text", + "content": "Figure 1. Our proposed bilateral MAE for efficient CIL. The Replay Buffer contains random patches selected from past task images, which is more efficient than storing whole images. Combining these with masked input data from the current task, the MAE simultaneously learns to classify and reconstruct images from the masked input. To further improve the reconstructed image quality and learned representations, embedding-level and image-level fusion is used to learn more stable representations and more detailed reconstructions for CIL." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 449, + 547, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 449, + 547, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 449, + 547, + 665 + ], + "type": "text", + "content": "Normally, only a fixed size of memory is allowed during incremental learning. Therefore, it limits the stored exemplars from past tasks. Other works exploit generative networks [35, 38, 43] (e.g., GANs) to synthesize samples from old tasks for replay. Although they can generate replay data to mitigate forgetting, a typical drawback is the quality of generated images, and that forgetting can also happen in generative models. In this work, we introduce Masked Autoencoders (MAEs) [11] as a base model to replay. It allows efficient exemplar storage by only requiring a small subset of patches to reconstruct whole images. Therefore, we can store more exemplars with the same amount of limited memory as other exemplar-based approaches. Compared to previous generative methods, replay by MAE is more stable because it uses partial cues to infer global information, which is task-agnostic and suffers less forgetting across tasks. This relieves the unstable generation effect of GANs across tasks with stationary image patches." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 547, + 713 + ], + "type": "text", + "content": "Masked Autoencoders (MAEs) [11] were initially proposed to learn better feature representations in self-supervised learning scenarios. In this work, we see it as efficient incremental learners and propose a novel bilat" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 702, + 212, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 212, + 713 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 212, + 713 + ], + "type": "text", + "content": "*Corresponding author (xialei@nankai.edu.cn)" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "19104" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 203 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 203 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 203 + ], + "type": "text", + "content": "eral transformer architecture for efficient exemplar replay in CIL. Our main idea is simple: by randomly masking patches of input images and training models to reconstruct the masked pixels, MAEs can provide a new form of self-supervised representation learning for CIL and thus learn more generalizable representations essential for CIL. In addition, leveraging a supervised objective with classification labels benefits unsupervised MAE in training efficiency and model robustness [18]. Masked inputs can also serve as strong classification regularization by only providing a random subset of data." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 204, + 289, + 407 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 204, + 289, + 407 + ], + "spans": [ + { + "bbox": [ + 46, + 204, + 289, + 407 + ], + "type": "text", + "content": "When learning new tasks, the MAE can coarsely reconstruct images from sparsely sampled patches from exemplars. This process enables the framework to generate reconstructed replay data, but two problems remain: (i) the generated images tend to have less detailed and less realistic textures, which reduces data diversity for replay; and (ii) on the embedding-level, the linear classifier lacks information from low-level features. Therefore, we introduce a bilateral MAE framework with image-level and embedding-level fusion for CIL (see Fig. 1 for a schematic overview). Fusing a complementary detailed and reconstructed image alleviates catastrophic forgetting by enriching the insufficient replay data with detailed, high-quality data distributions. Embedding-level fusion from the two branches also maintains stable and diverse embeddings, and our framework can thus achieve a better trade-off between plasticity and stability." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 407, + 287, + 431 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 407, + 287, + 431 + ], + "spans": [ + { + "bbox": [ + 47, + 407, + 287, + 431 + ], + "type": "text", + "content": "The main contributions of our bilateral MAE framework are threefold:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 58, + 435, + 287, + 580 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 58, + 435, + 287, + 484 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 435, + 287, + 484 + ], + "spans": [ + { + "bbox": [ + 58, + 435, + 287, + 484 + ], + "type": "text", + "content": "- We introduce an MAE framework for efficient incremental learning that incorporates benefits from both self-supervised reconstruction and data generation for replay." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 58, + 490, + 287, + 538 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 490, + 287, + 538 + ], + "spans": [ + { + "bbox": [ + 58, + 490, + 287, + 538 + ], + "type": "text", + "content": "- To further boost the quality of reconstructed images and learning efficiency, we design a novel bilateral MAE with two complementary branches for better-reconstructed images and regularized representations." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 58, + 544, + 287, + 580 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 544, + 287, + 580 + ], + "spans": [ + { + "bbox": [ + 58, + 544, + 287, + 580 + ], + "type": "text", + "content": "- Our approach achieves state-of-the-art performance under different CIL settings on CIFAR-100, ImageNet-Subset, and ImageNet-Full." + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 47, + 590, + 134, + 601 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 590, + 134, + 601 + ], + "spans": [ + { + "bbox": [ + 47, + 590, + 134, + 601 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 605, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 289, + 715 + ], + "type": "text", + "content": "Incremental learning. Various methods have been proposed for incremental learning in the past few years [2, 5]. Recent works can be coarsely grouped into three categories: replay-based, regularization-based, and parameter-isolation methods. Replay-based methods mitigate the task-recency bias by replaying training samples from previous tasks. In addition to replaying samples, BiC [36], PODNet [8], and iCaRL [29] apply a distillation loss to prevent forgetting and enhance model stability. GEM [21], AGEM [3]," + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 72, + 545, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 120 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 120 + ], + "type": "text", + "content": "and MER [30] exploit past-task exemplars by modifying gradients on current training samples to match old samples. Rehearsal-based methods may cause models to overfit stored samples." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 120, + 545, + 192 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 120, + 545, + 192 + ], + "spans": [ + { + "bbox": [ + 304, + 120, + 545, + 192 + ], + "type": "text", + "content": "Pseudo-replay methods reconstruct the old data for replay. MeRGANs [35] use conditional GANs to balance the generation of old and current samples. Besides, dreamingrelevant methods like DeepInversion [41] and AlwaysBeDreaming [33] exploit backward signals to generate images similar to the original datasets." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 192, + 545, + 288 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 192, + 545, + 288 + ], + "spans": [ + { + "bbox": [ + 304, + 192, + 545, + 288 + ], + "type": "text", + "content": "Regularization-based approaches, such as LwF [17], EWC [15], and DMC [44], offer methods to learn better representations while leaving enough plasticity for adaptation to new tasks. Parameter-isolation methods [24,39] use models with different computational graphs for each task. With the help of growing models, new model branches mitigate catastrophic forgetting at the cost of more parameters and computational costs." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 300, + 545, + 407 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 300, + 545, + 407 + ], + "spans": [ + { + "bbox": [ + 304, + 300, + 545, + 407 + ], + "type": "text", + "content": "Self-Supervised Learning. Self-supervised learning [7, 27, 37] has been shown to help models learn generalizable features, which makes it natural to consider its application to incremental learning. Early works used pretext tasks like patch permutation [27] or rotation prediction [10]. Contrastive learning approaches model the pairwise similarity and dissimilarity between samples [4]. By comparison, MAEs [11] learn feature representations by reconstructing images from a masked version of inputs." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 407, + 545, + 515 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 407, + 545, + 515 + ], + "spans": [ + { + "bbox": [ + 304, + 407, + 545, + 515 + ], + "type": "text", + "content": "There are a few works proposing self-supervision for class incremental learning. PASS [46] incorporates rotation prediction [10] to learn representations transferable across tasks. DualNet [28] uses Barlow Twins [42] to introduce a \"slow\" task that regularizes the \"fast\" incremental learning. In this paper, we explore the framework generates data for replay while applying semantic and detailed-level self-supervision, which mitigates forgetting via richer replay data and more generalizable features." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 526, + 446, + 539 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 526, + 446, + 539 + ], + "spans": [ + { + "bbox": [ + 305, + 526, + 446, + 539 + ], + "type": "text", + "content": "3. Continual MAE for CIL" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 547, + 545, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 547, + 545, + 594 + ], + "spans": [ + { + "bbox": [ + 304, + 547, + 545, + 594 + ], + "type": "text", + "content": "In this section, we first define the class incremental learning problem and the basic MAE model. Then we introduce our incremental learning framework and the bilateral MAE architecture it is based on." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 602, + 392, + 614 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 602, + 392, + 614 + ], + "spans": [ + { + "bbox": [ + 305, + 602, + 392, + 614 + ], + "type": "text", + "content": "3.1. Preliminaries" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": "The class incremental learning problem. CIL aims to sequentially learn tasks with new classes while preventing or alleviating forgetting of old tasks. At a specific phase of learning task " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "t \\in \\{1,2,\\dots,T\\}" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": ", model training can exploit only data from the current task " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\{(x_i^t,y_i^t)\\}" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "x_{i}^{t}" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": " denotes image " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": " in task " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "y_{i}^{t}" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": " its corresponding class label. A CIL model typically consists of a feature extractor " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "F_{\\theta}" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": " and a common classifier " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "G_{\\phi}" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": " which grows at each new" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19105" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 71, + 545, + 251 + ], + "blocks": [ + { + "bbox": [ + 49, + 71, + 545, + 251 + ], + "lines": [ + { + "bbox": [ + 49, + 71, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 49, + 71, + 545, + 251 + ], + "type": "image", + "image_path": "d7ec2e7a634a1a011c36f513c120d12d55c85f74d0f43e3f7ec574b2c7118c6b.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 252, + 546, + 285 + ], + "lines": [ + { + "bbox": [ + 46, + 252, + 546, + 285 + ], + "spans": [ + { + "bbox": [ + 46, + 252, + 546, + 285 + ], + "type": "text", + "content": "Figure 2. Overall framework of our bilateral MAE for CIL. The masked input is passed through two branches with embedding-level fusion for classification and image-level fusion for reconstruction. Full images can be generated from a small sample of input patches and the reconstructed images can be used as replay." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "spans": [ + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "text", + "content": "task. At task " + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "inline_equation", + "content": "t + 1" + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "inline_equation", + "content": "C_{t + 1}" + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "text", + "content": " new classes are added to " + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "inline_equation", + "content": "G_{\\phi}" + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "text", + "content": ". The feature extractor " + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "inline_equation", + "content": "F_{\\theta}" + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "text", + "content": " first maps the input " + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "text", + "content": " to a deep feature vector " + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "inline_equation", + "content": "z = F_{\\theta}(x)\\in \\mathbb{R}^{d}" + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "text", + "content": " is the dimension of the output feature representation, and then the unified classifier " + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "inline_equation", + "content": "G_{\\phi}(z)\\in \\mathbb{R}^{C_{1:t}}" + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "text", + "content": " produces a probability distribution over classes " + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "inline_equation", + "content": "C_{1:t}" + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "text", + "content": " which is used to make predictions on input " + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 46, + 305, + 287, + 378 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 378, + 287, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 378, + 287, + 498 + ], + "spans": [ + { + "bbox": [ + 46, + 378, + 287, + 498 + ], + "type": "text", + "content": "When training task " + }, + { + "bbox": [ + 46, + 378, + 287, + 498 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 378, + 287, + 498 + ], + "type": "text", + "content": ", the model aims to minimize losses on the current task without degrading performance on previous tasks. A common technique for mitigating forgetting is to retain a small buffer of training samples from previous tasks. Let " + }, + { + "bbox": [ + 46, + 378, + 287, + 498 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 46, + 378, + 287, + 498 + ], + "type": "text", + "content": " be this buffer of previous task samples. One essential problem for CIL is the limited amount of replay data. Compared to the full data of current task " + }, + { + "bbox": [ + 46, + 378, + 287, + 498 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 378, + 287, + 498 + ], + "type": "text", + "content": ", only a few samples of old task classes are available (20 samples per class is a common setting), which causes imbalanced training between new and old tasks." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "spans": [ + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "text", + "content": "An MAE framework for classification. An MAE first crops input image " + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "text", + "content": " into non-overlapping patches, and we denote the number of patches in the full image " + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "inline_equation", + "content": "N_{f}" + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "text", + "content": ". After patchification, the MAE randomly masks a proportion " + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "inline_equation", + "content": "r \\in [0,1]" + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "text", + "content": " of the " + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "inline_equation", + "content": "N_{f}" + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "text", + "content": " patches, leaving only " + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "inline_equation", + "content": "N = \\lfloor N_{f} \\times (1 - r) \\rfloor" + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "text", + "content": " patches. Then these sampled " + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "inline_equation", + "content": "K \\times K" + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "text", + "content": " pixel patches are mapped to a visual embedding of dimension " + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "text", + "content": " using an MLP. After concatenating with a class token, the result is a tensor of size " + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "inline_equation", + "content": "\\mathbb{R}^{(N + 1) \\times D}" + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "text", + "content": ". After positionally encoding the original patch locations, this input is passed to the MAE transformer encoder. This operation maintains the same shape of embedding. The output class token embedding can be used for classification with a cross-entropy loss " + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_t^{\\mathrm{cls}}" + }, + { + "bbox": [ + 47, + 510, + 287, + 677 + ], + "type": "text", + "content": ", as shown in Fig. 2." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "type": "text", + "content": "For the MAE Decoder, learnable mask tokens are inserted into the embeddings in place of the masked patches, and the shape of output from the MAE Encoder changes" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "spans": [ + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "type": "text", + "content": "from " + }, + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "type": "inline_equation", + "content": "\\mathbb{R}^{(N + 1)\\times D}" + }, + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "type": "inline_equation", + "content": "\\mathbb{R}^{(N_f + 1)\\times D}" + }, + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "type": "text", + "content": ". Although the decoder is not used for classification, it helps the network backpropagate image-level reconstruction supervision to the embedding-level. This stabilizes the image embedding and helps the optimization process. Also, the reconstructed images after decoding provide richer, higher-quality replay data. To limit computation, we use a single-layer transformer block for the decoder. The additional classification loss after the encoder speeds up convergence and improves reconstruction efficiency during training. The mean squared error between the input image " + }, + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "type": "text", + "content": " and reconstructed image " + }, + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "type": "inline_equation", + "content": "\\hat{x}" + }, + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "type": "text", + "content": " is used as the reconstruction loss function " + }, + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_t^{\\mathrm{rec}}(x,\\hat{x})" + }, + { + "bbox": [ + 304, + 304, + 545, + 450 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 455, + 512, + 468 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 455, + 512, + 468 + ], + "spans": [ + { + "bbox": [ + 306, + 455, + 512, + 468 + ], + "type": "text", + "content": "3.2. Efficient Exemplar Storage with MAEs" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 474, + 545, + 545 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 474, + 545, + 545 + ], + "spans": [ + { + "bbox": [ + 304, + 474, + 545, + 545 + ], + "type": "text", + "content": "After training each task, we save small sample images and apply random masking. Keeping the same storage size can save more replay data per class since each sample occupies less space. For example, a masking ratio of 0.75 allows us to save " + }, + { + "bbox": [ + 304, + 474, + 545, + 545 + ], + "type": "inline_equation", + "content": "4 \\times" + }, + { + "bbox": [ + 304, + 474, + 545, + 545 + ], + "type": "text", + "content": " the number of (reconstructible) samples compared to conventional replay methods." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "text", + "content": "Let " + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "inline_equation", + "content": "P" + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "text", + "content": " denote the size of the image and patch, respectively. Our encoder patchifies the input image into " + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "inline_equation", + "content": "\\frac{S}{P} \\times \\frac{S}{P}" + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "text", + "content": " patches. We save the 2D index " + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "inline_equation", + "content": "(i,j)" + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "text", + "content": " for each patch that is not masked. We need only one byte to save these indexes since their range is less than 255. The two additional bytes for saving this 2D index are negligible compared to the saved image patches. A masking ratio 0.75 on a " + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "inline_equation", + "content": "224 \\times 224" + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "text", + "content": " image requires only 36.75KB of storage. For " + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "inline_equation", + "content": "P = 16" + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "text", + "content": ", the number of saved patches is " + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "inline_equation", + "content": "(1 - 0.75) \\times (\\frac{224}{16})^2 = 49" + }, + { + "bbox": [ + 304, + 545, + 545, + 665 + ], + "type": "text", + "content": ", and the storage of indexes is only 98B." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 671, + 432, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 671, + 432, + 682 + ], + "spans": [ + { + "bbox": [ + 306, + 671, + 432, + 682 + ], + "type": "text", + "content": "3.3. Bilateral MAE Fusion" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": "To further boost reconstruction quality and embedding diversity, we propose a two-branches MAE to learn global" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19106" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 69, + 282, + 145 + ], + "blocks": [ + { + "bbox": [ + 51, + 69, + 282, + 145 + ], + "lines": [ + { + "bbox": [ + 51, + 69, + 282, + 145 + ], + "spans": [ + { + "bbox": [ + 51, + 69, + 282, + 145 + ], + "type": "image", + "image_path": "8821003216817f7bb3843edc8f8423a18f766d1c82319b99994a21d92b7d6063.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 145, + 287, + 199 + ], + "lines": [ + { + "bbox": [ + 47, + 145, + 287, + 199 + ], + "spans": [ + { + "bbox": [ + 47, + 145, + 287, + 199 + ], + "type": "text", + "content": "Figure 3. An example of extracting detailed images with reconstructed results from different masking ratios " + }, + { + "bbox": [ + 47, + 145, + 287, + 199 + ], + "type": "inline_equation", + "content": "r_1" + }, + { + "bbox": [ + 47, + 145, + 287, + 199 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 145, + 287, + 199 + ], + "type": "inline_equation", + "content": "r_2" + }, + { + "bbox": [ + 47, + 145, + 287, + 199 + ], + "type": "text", + "content": ". The third image comes from the difference between the previous two, and the last image is the extracted high-frequency component from the third image." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "code", + "bbox": [ + 47, + 227, + 287, + 262 + ], + "blocks": [ + { + "bbox": [ + 48, + 212, + 241, + 223 + ], + "lines": [ + { + "bbox": [ + 48, + 212, + 241, + 223 + ], + "spans": [ + { + "bbox": [ + 48, + 212, + 241, + 223 + ], + "type": "text", + "content": "Algorithm 1 Pseudocode of our Bilateral MAE." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "code_caption" + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "lines": [ + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "spans": [ + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "text", + "content": "Input: The number of task " + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "text", + "content": ", training samples " + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "inline_equation", + "content": "D_{t} = \\{(x_{i},y_{i})\\}_{t}" + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "text", + "content": " of task " + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "text", + "content": ", model " + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "inline_equation", + "content": "\\Theta^0" + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "text", + "content": ", replay buffer " + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "text", + "content": ", and masking ratios " + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "inline_equation", + "content": "r, r_1, r_2" + }, + { + "bbox": [ + 47, + 227, + 287, + 262 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "code_body" + } + ], + "index": 3, + "sub_type": "code", + "guess_lang": "latex" + }, + { + "type": "code", + "bbox": [ + 53, + 275, + 160, + 286 + ], + "blocks": [ + { + "bbox": [ + 48, + 263, + 130, + 274 + ], + "lines": [ + { + "bbox": [ + 48, + 263, + 130, + 274 + ], + "spans": [ + { + "bbox": [ + 48, + 263, + 130, + 274 + ], + "type": "text", + "content": "Output: model " + }, + { + "bbox": [ + 48, + 263, + 130, + 274 + ], + "type": "inline_equation", + "content": "\\Theta^T" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "code_caption" + }, + { + "bbox": [ + 53, + 275, + 160, + 286 + ], + "lines": [ + { + "bbox": [ + 53, + 275, + 160, + 286 + ], + "spans": [ + { + "bbox": [ + 53, + 275, + 160, + 286 + ], + "type": "text", + "content": "1: for " + }, + { + "bbox": [ + 53, + 275, + 160, + 286 + ], + "type": "inline_equation", + "content": "t \\in \\{1, 2, \\dots, T\\}" + }, + { + "bbox": [ + 53, + 275, + 160, + 286 + ], + "type": "text", + "content": " do" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "code_body" + } + ], + "index": 5, + "sub_type": "code", + "guess_lang": "txt" + }, + { + "type": "code", + "bbox": [ + 54, + 287, + 129, + 297 + ], + "blocks": [ + { + "bbox": [ + 54, + 287, + 129, + 297 + ], + "lines": [ + { + "bbox": [ + 54, + 287, + 129, + 297 + ], + "spans": [ + { + "bbox": [ + 54, + 287, + 129, + 297 + ], + "type": "text", + "content": "2: " + }, + { + "bbox": [ + 54, + 287, + 129, + 297 + ], + "type": "inline_equation", + "content": "\\Theta^t\\gets \\Theta^{t - 1}" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "code_body" + } + ], + "index": 6, + "sub_type": "code", + "guess_lang": "txt" + }, + { + "type": "code", + "bbox": [ + 54, + 300, + 231, + 311 + ], + "blocks": [ + { + "bbox": [ + 54, + 300, + 231, + 311 + ], + "lines": [ + { + "bbox": [ + 54, + 300, + 231, + 311 + ], + "spans": [ + { + "bbox": [ + 54, + 300, + 231, + 311 + ], + "type": "text", + "content": "3: " + }, + { + "bbox": [ + 54, + 300, + 231, + 311 + ], + "type": "inline_equation", + "content": "R_{t}\\gets \\mathrm{ReconstructOldSamples}(\\epsilon_{t},r)" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "code_body" + } + ], + "index": 7, + "sub_type": "code", + "guess_lang": "javascript" + }, + { + "type": "code", + "bbox": [ + 54, + 312, + 177, + 323 + ], + "blocks": [ + { + "bbox": [ + 54, + 312, + 177, + 323 + ], + "lines": [ + { + "bbox": [ + 54, + 312, + 177, + 323 + ], + "spans": [ + { + "bbox": [ + 54, + 312, + 177, + 323 + ], + "type": "text", + "content": "4: while not converged do" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "code_body" + } + ], + "index": 8, + "sub_type": "code", + "guess_lang": "txt" + }, + { + "type": "code", + "bbox": [ + 54, + 323, + 201, + 335 + ], + "blocks": [ + { + "bbox": [ + 54, + 323, + 201, + 335 + ], + "lines": [ + { + "bbox": [ + 54, + 323, + 201, + 335 + ], + "spans": [ + { + "bbox": [ + 54, + 323, + 201, + 335 + ], + "type": "text", + "content": "5: " + }, + { + "bbox": [ + 54, + 323, + 201, + 335 + ], + "type": "inline_equation", + "content": "(x,y)\\gets" + }, + { + "bbox": [ + 54, + 323, + 201, + 335 + ], + "type": "text", + "content": " Sample " + }, + { + "bbox": [ + 54, + 323, + 201, + 335 + ], + "type": "inline_equation", + "content": "(R_{t},D_{t})" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "code_body" + } + ], + "index": 9, + "sub_type": "code", + "guess_lang": "javascript" + }, + { + "type": "code", + "bbox": [ + 54, + 335, + 238, + 346 + ], + "blocks": [ + { + "bbox": [ + 54, + 335, + 238, + 346 + ], + "lines": [ + { + "bbox": [ + 54, + 335, + 238, + 346 + ], + "spans": [ + { + "bbox": [ + 54, + 335, + 238, + 346 + ], + "type": "text", + "content": "6: " + }, + { + "bbox": [ + 54, + 335, + 238, + 346 + ], + "type": "inline_equation", + "content": "(\\mathcal{L}_t^{\\mathrm{cls}},\\mathcal{L}_t^{\\mathrm{rec}})\\gets" + }, + { + "bbox": [ + 54, + 335, + 238, + 346 + ], + "type": "text", + "content": " BilateralMAE " + }, + { + "bbox": [ + 54, + 335, + 238, + 346 + ], + "type": "inline_equation", + "content": "(x,y)" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "code_body" + } + ], + "index": 10, + "sub_type": "code", + "guess_lang": "txt" + }, + { + "type": "code", + "bbox": [ + 54, + 347, + 272, + 358 + ], + "blocks": [ + { + "bbox": [ + 54, + 347, + 272, + 358 + ], + "lines": [ + { + "bbox": [ + 54, + 347, + 272, + 358 + ], + "spans": [ + { + "bbox": [ + 54, + 347, + 272, + 358 + ], + "type": "text", + "content": "7: " + }, + { + "bbox": [ + 54, + 347, + 272, + 358 + ], + "type": "inline_equation", + "content": "(\\hat{x}_1, \\hat{x}_2) \\gets \\text{MaskAndReconstruct}(x, r_1, r_2)" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "code_body" + } + ], + "index": 11, + "sub_type": "code", + "guess_lang": "latex" + }, + { + "type": "code", + "bbox": [ + 54, + 359, + 244, + 371 + ], + "blocks": [ + { + "bbox": [ + 54, + 359, + 244, + 371 + ], + "lines": [ + { + "bbox": [ + 54, + 359, + 244, + 371 + ], + "spans": [ + { + "bbox": [ + 54, + 359, + 244, + 371 + ], + "type": "text", + "content": "8: " + }, + { + "bbox": [ + 54, + 359, + 244, + 371 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_t^{\\mathrm{det}}\\gets" + }, + { + "bbox": [ + 54, + 359, + 244, + 371 + ], + "type": "text", + "content": " ComputeDetailLoss " + }, + { + "bbox": [ + 54, + 359, + 244, + 371 + ], + "type": "inline_equation", + "content": "(\\hat{x}_1,\\hat{x}_2)" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "code_body" + } + ], + "index": 12, + "sub_type": "code", + "guess_lang": "txt" + }, + { + "type": "code", + "bbox": [ + 54, + 371, + 253, + 383 + ], + "blocks": [ + { + "bbox": [ + 54, + 371, + 253, + 383 + ], + "lines": [ + { + "bbox": [ + 54, + 371, + 253, + 383 + ], + "spans": [ + { + "bbox": [ + 54, + 371, + 253, + 383 + ], + "type": "text", + "content": "9: train " + }, + { + "bbox": [ + 54, + 371, + 253, + 383 + ], + "type": "inline_equation", + "content": "\\Theta^t" + }, + { + "bbox": [ + 54, + 371, + 253, + 383 + ], + "type": "text", + "content": " by minimizing " + }, + { + "bbox": [ + 54, + 371, + 253, + 383 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_t" + }, + { + "bbox": [ + 54, + 371, + 253, + 383 + ], + "type": "text", + "content": " from Eq. 12" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "code_body" + } + ], + "index": 13, + "sub_type": "code", + "guess_lang": "txt" + }, + { + "type": "code", + "bbox": [ + 51, + 384, + 123, + 393 + ], + "blocks": [ + { + "bbox": [ + 51, + 384, + 123, + 393 + ], + "lines": [ + { + "bbox": [ + 51, + 384, + 123, + 393 + ], + "spans": [ + { + "bbox": [ + 51, + 384, + 123, + 393 + ], + "type": "text", + "content": "10: end while" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "code_body" + } + ], + "index": 14, + "sub_type": "code", + "guess_lang": "txt" + }, + { + "type": "code", + "bbox": [ + 51, + 396, + 97, + 405 + ], + "blocks": [ + { + "bbox": [ + 51, + 396, + 97, + 405 + ], + "lines": [ + { + "bbox": [ + 51, + 396, + 97, + 405 + ], + "spans": [ + { + "bbox": [ + 51, + 396, + 97, + 405 + ], + "type": "text", + "content": "11: end for" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "code_body" + } + ], + "index": 15, + "sub_type": "code", + "guess_lang": "txt" + }, + { + "bbox": [ + 46, + 430, + 287, + 502 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 430, + 287, + 502 + ], + "spans": [ + { + "bbox": [ + 46, + 430, + 287, + 502 + ], + "type": "text", + "content": "and detailed classification and image reconstruction knowledge. We illustrate the overall framework in Fig. 2. Bilateral fusion at the embedding-level aims to improve representations diversity. Reconstruction learning at the image-level yields high-quality replay data and stable self-supervision for CIL." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 46, + 517, + 287, + 589 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 517, + 287, + 589 + ], + "spans": [ + { + "bbox": [ + 46, + 517, + 287, + 589 + ], + "type": "text", + "content": "Embedding fusion. In the following we use " + }, + { + "bbox": [ + 46, + 517, + 287, + 589 + ], + "type": "inline_equation", + "content": "F_{\\theta[:1]}" + }, + { + "bbox": [ + 46, + 517, + 287, + 589 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 517, + 287, + 589 + ], + "type": "inline_equation", + "content": "F_{\\theta[1:]}" + }, + { + "bbox": [ + 46, + 517, + 287, + 589 + ], + "type": "text", + "content": " to denote our transformer encoder's first and following blocks. Let " + }, + { + "bbox": [ + 46, + 517, + 287, + 589 + ], + "type": "inline_equation", + "content": "H_{\\theta}" + }, + { + "bbox": [ + 46, + 517, + 287, + 589 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 517, + 287, + 589 + ], + "type": "inline_equation", + "content": "E_{\\theta}" + }, + { + "bbox": [ + 46, + 517, + 287, + 589 + ], + "type": "text", + "content": " represent the detailed block and embedding fusion module in Fig. 2, which are standard MLP layers and attention blocks, respectively. The classification loss is computed as:" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 123, + 601, + 286, + 613 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 123, + 601, + 286, + 613 + ], + "spans": [ + { + "bbox": [ + 123, + 601, + 286, + 613 + ], + "type": "interline_equation", + "content": "f = F _ {\\theta [: 1 ]} (\\operatorname {m a s k} (x, r)) \\tag {1}", + "image_path": "baab9c0284933234ae5f635bb5cf29765544fa7cfcc1d1228f81163acefc4391.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 125, + 616, + 286, + 628 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 125, + 616, + 286, + 628 + ], + "spans": [ + { + "bbox": [ + 125, + 616, + 286, + 628 + ], + "type": "interline_equation", + "content": "z = E _ {\\theta} \\left(F _ {\\theta [ 1: ]} (f), H _ {\\theta} (f)\\right) \\tag {2}", + "image_path": "00262637cd9f377c3ba898199ac3214179ac434db6c7b77f5f5db6dcb74a3d5e.jpg" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 90, + 631, + 286, + 644 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 90, + 631, + 286, + 644 + ], + "spans": [ + { + "bbox": [ + 90, + 631, + 286, + 644 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {t} ^ {\\mathrm {c l s}} (x, y) = \\mathcal {L} _ {\\mathrm {c e}} \\left(G _ {\\phi} (z), y\\right), \\tag {3}", + "image_path": "8e47ac4370bd6584c13e9a0e5cd06f02de445e0a1d9483c62f607ca8389c6782.jpg" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "type": "inline_equation", + "content": "\\mathrm{mask}(x,r)" + }, + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "type": "text", + "content": " denotes applying random masking with ratio " + }, + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "type": "text", + "content": " on image " + }, + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "type": "text", + "content": " is the embedding extracted by the first encoder block, which is the input to the two branches of our Bilateral MAE, and " + }, + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "type": "inline_equation", + "content": "G_{\\phi}(z)" + }, + { + "bbox": [ + 46, + 654, + 287, + 715 + ], + "type": "text", + "content": " is the estimated class distribution used for in the cross entropy loss." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "text", + "content": "Image fusion with detailed loss. For the detailed head and corresponding loss, we discovered that working in the frequency domain makes it easier for the network to attend to high-frequency details, which is exactly what the detailed branch should reconstruct. We define a frequency-masking function " + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "inline_equation", + "content": "M(\\cdot)" + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "text", + "content": " that converts its argument (an image patch) to the frequency domain, then masks out low frequencies using a circular mask around the origin. As shown in Fig. 2, the MAE decoder is shared by the two branches of our model since they have similar reconstruction tasks, as well as input and output shapes. Let " + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "inline_equation", + "content": "D_{\\theta}" + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "text", + "content": " be this shared decoder, then the image-level outputs of the two branches and the reconstruction loss " + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_t^{\\mathrm{rec}}" + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "text", + "content": " are:" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 369, + 238, + 545, + 251 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 369, + 238, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 369, + 238, + 545, + 251 + ], + "type": "interline_equation", + "content": "f = F _ {\\theta [: 1 ]} (\\operatorname {m a s k} (x, r)) \\tag {4}", + "image_path": "e88da15f614c7b2d29088069f60942c45785a66f7ac6592ebf5229d8fb300c16.jpg" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 366, + 253, + 545, + 266 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 366, + 253, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 366, + 253, + 545, + 266 + ], + "type": "interline_equation", + "content": "x ^ {\\prime} = D _ {\\theta} \\left(F _ {\\theta [ 1: ]} (f)\\right) \\tag {5}", + "image_path": "d181dc739cc21473e202f99a9f368bed46973e7fa4da836257e332e0372be5d5.jpg" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 364, + 267, + 545, + 281 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 364, + 267, + 545, + 281 + ], + "spans": [ + { + "bbox": [ + 364, + 267, + 545, + 281 + ], + "type": "interline_equation", + "content": "x ^ {\\prime \\prime} = \\text {i f t 2} \\left(M \\left(D _ {\\theta} \\left(H _ {\\theta} (f)\\right)\\right)\\right) \\tag {6}", + "image_path": "0d0f94fb112c44aab6043c1006ee00a8c5fb31ade948c7caf882e8a89facebde.jpg" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 369, + 282, + 545, + 295 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 369, + 282, + 545, + 295 + ], + "spans": [ + { + "bbox": [ + 369, + 282, + 545, + 295 + ], + "type": "interline_equation", + "content": "\\hat {x} = x ^ {\\prime} + x ^ {\\prime \\prime} \\tag {7}", + "image_path": "4e3152678c3d14f9e2c229280528998bbf6c9d82c9c26093522b0f232803916c.jpg" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 358, + 297, + 545, + 311 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 358, + 297, + 545, + 311 + ], + "spans": [ + { + "bbox": [ + 358, + 297, + 545, + 311 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {t} ^ {\\text {r e c}} = \\mathcal {L} _ {\\text {m s e}} (x, \\hat {x}), \\tag {8}", + "image_path": "23e8745fc2de25408418ea7c9eb7700ff281b91b2ab78ed82f18623eb563833b.jpg" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 306, + 319, + 545, + 344 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 319, + 545, + 344 + ], + "spans": [ + { + "bbox": [ + 306, + 319, + 545, + 344 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 306, + 319, + 545, + 344 + ], + "type": "inline_equation", + "content": "x'" + }, + { + "bbox": [ + 306, + 319, + 545, + 344 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 319, + 545, + 344 + ], + "type": "inline_equation", + "content": "x''" + }, + { + "bbox": [ + 306, + 319, + 545, + 344 + ], + "type": "text", + "content": " are the main and residual detailed outputs, respectively, and ifft2 is the inverse Fast Fourier Transform." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 304, + 344, + 545, + 392 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 344, + 545, + 392 + ], + "spans": [ + { + "bbox": [ + 304, + 344, + 545, + 392 + ], + "type": "text", + "content": "The detailed loss " + }, + { + "bbox": [ + 304, + 344, + 545, + 392 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_t^{\\mathrm{det}}" + }, + { + "bbox": [ + 304, + 344, + 545, + 392 + ], + "type": "text", + "content": " also makes use of the frequencymasking function " + }, + { + "bbox": [ + 304, + 344, + 545, + 392 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 304, + 344, + 545, + 392 + ], + "type": "text", + "content": " to compare the output of the detailed branch and the difference between two MAE reconstructions of the input image:" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 337, + 403, + 545, + 415 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 337, + 403, + 545, + 415 + ], + "spans": [ + { + "bbox": [ + 337, + 403, + 545, + 415 + ], + "type": "interline_equation", + "content": "\\hat {x} _ {1} = D _ {\\theta} \\left(F _ {\\theta} \\left(\\operatorname {m a s k} \\left(x, r _ {1}\\right)\\right)\\right) \\tag {9}", + "image_path": "13da1a238c01a528be8e4dc5dbe55f5b06f106944c23d7091b65eaca68c82f94.jpg" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 337, + 418, + 545, + 430 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 337, + 418, + 545, + 430 + ], + "spans": [ + { + "bbox": [ + 337, + 418, + 545, + 430 + ], + "type": "interline_equation", + "content": "\\hat {x} _ {2} = D _ {\\theta} \\left(F _ {\\theta} (\\operatorname {m a s k} (x, r _ {2}))\\right) \\tag {10}", + "image_path": "037b0c74806e4418c9074d0790a95d782de8b318a71343aa9310e672d6b58237.jpg" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 329, + 431, + 545, + 445 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 329, + 431, + 545, + 445 + ], + "spans": [ + { + "bbox": [ + 329, + 431, + 545, + 445 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {t} ^ {\\mathrm {d e t}} = | | M \\left(D _ {\\theta} \\left(H _ {\\theta} (f)\\right) - M \\left(\\hat {x} _ {2} - \\hat {x} _ {1}\\right) \\right| | _ {1}, \\tag {11}", + "image_path": "0ca637d5dbac2638c4d3da990daeedb4a090bc4586ddd4779c3b870fc7837241.jpg" + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "spans": [ + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "inline_equation", + "content": "\\hat{x}_1" + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "inline_equation", + "content": "\\hat{x}_2" + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "text", + "content": " are two reconstructed images (detached from the gradient computation graph) using different masking ratios " + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "inline_equation", + "content": "r_1" + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "inline_equation", + "content": "r_2" + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "text", + "content": ", respectively. The residual difference " + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "inline_equation", + "content": "\\hat{x}_2 - \\hat{x}_1" + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "text", + "content": " is used as supervision in the frequency domain for the detailed branch in loss " + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_t^{\\mathrm{det}}" + }, + { + "bbox": [ + 304, + 455, + 545, + 525 + ], + "type": "text", + "content": ". An illustration can be found in Fig. 3." + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 304, + 526, + 545, + 563 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 526, + 545, + 563 + ], + "spans": [ + { + "bbox": [ + 304, + 526, + 545, + 563 + ], + "type": "text", + "content": "A weighted sum of classification loss " + }, + { + "bbox": [ + 304, + 526, + 545, + 563 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_t^{\\mathrm{cls}}" + }, + { + "bbox": [ + 304, + 526, + 545, + 563 + ], + "type": "text", + "content": ", reconstruction loss " + }, + { + "bbox": [ + 304, + 526, + 545, + 563 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_t^{\\mathrm{rec}}" + }, + { + "bbox": [ + 304, + 526, + 545, + 563 + ], + "type": "text", + "content": ", and detail loss " + }, + { + "bbox": [ + 304, + 526, + 545, + 563 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_t^{\\mathrm{det}}" + }, + { + "bbox": [ + 304, + 526, + 545, + 563 + ], + "type": "text", + "content": " is used as the overall loss for training:" + } + ] + } + ], + "index": 35 + }, + { + "bbox": [ + 343, + 572, + 545, + 586 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 343, + 572, + 545, + 586 + ], + "spans": [ + { + "bbox": [ + 343, + 572, + 545, + 586 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {t} = \\lambda_ {\\mathrm {c l s}} \\mathcal {L} _ {t} ^ {\\mathrm {c l s}} + \\lambda_ {\\mathrm {r e c}} \\mathcal {L} _ {t} ^ {\\mathrm {r e c}} + \\lambda_ {\\mathrm {d e t}} \\mathcal {L} _ {t} ^ {\\mathrm {d e t}}. \\tag {12}", + "image_path": "37328f69e6174707a6aedb368058c41255194fc9376c0afbe9a8ae5f224c7d53.jpg" + } + ] + } + ], + "index": 36 + }, + { + "bbox": [ + 306, + 595, + 515, + 608 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 595, + 515, + 608 + ], + "spans": [ + { + "bbox": [ + 306, + 595, + 515, + 608 + ], + "type": "text", + "content": "Pseudocode for our method is given in Algorithm 1." + } + ] + } + ], + "index": 37 + }, + { + "bbox": [ + 306, + 619, + 431, + 632 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 619, + 431, + 632 + ], + "spans": [ + { + "bbox": [ + 306, + 619, + 431, + 632 + ], + "type": "text", + "content": "4. Experimental Results" + } + ] + } + ], + "index": 38 + }, + { + "bbox": [ + 306, + 639, + 485, + 651 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 639, + 485, + 651 + ], + "spans": [ + { + "bbox": [ + 306, + 639, + 485, + 651 + ], + "type": "text", + "content": "4.1. Benchmarks and Implementation" + } + ] + } + ], + "index": 39 + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "Datasets and settings. We experiment on three datasets: CIFAR-100 [16], ImageNet-Subset, and ImageNet-Full [6] to evaluate the performance of our approach. For CIFAR-100 and ImageNet-Subset, we test on 10-, 20- and 50-task scenarios, all with equal numbers of classes per task. We" + } + ] + } + ], + "index": 40 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19107" + } + ] + } + ], + "index": 41 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 100, + 79, + 228, + 209 + ], + "blocks": [ + { + "bbox": [ + 100, + 79, + 228, + 209 + ], + "lines": [ + { + "bbox": [ + 100, + 79, + 228, + 209 + ], + "spans": [ + { + "bbox": [ + 100, + 79, + 228, + 209 + ], + "type": "image", + "image_path": "bcf872f93dee9c777892de3c804c9e49d4c2abab9dd7f64153954d0526cc9dfa.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 104, + 211, + 485, + 222 + ], + "lines": [ + { + "bbox": [ + 104, + 211, + 485, + 222 + ], + "spans": [ + { + "bbox": [ + 104, + 211, + 485, + 222 + ], + "type": "text", + "content": "Figure 4. Performance evolution over incremental tasks on CIFAR-100 on 10-, 20- and 50-task scenarios." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 231, + 79, + 359, + 209 + ], + "blocks": [ + { + "bbox": [ + 231, + 79, + 359, + 209 + ], + "lines": [ + { + "bbox": [ + 231, + 79, + 359, + 209 + ], + "spans": [ + { + "bbox": [ + 231, + 79, + 359, + 209 + ], + "type": "image", + "image_path": "8fe608cc81c9ed84b0c7530029041ac67aafb95127a0752dbf0ba1a914d2e830.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 362, + 79, + 490, + 209 + ], + "blocks": [ + { + "bbox": [ + 362, + 79, + 490, + 209 + ], + "lines": [ + { + "bbox": [ + 362, + 79, + 490, + 209 + ], + "spans": [ + { + "bbox": [ + 362, + 79, + 490, + 209 + ], + "type": "image", + "image_path": "a1b493e45cafadc068437d8be0b74033bb4b91d9e0328768730939e0564160e9.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 126, + 231, + 468, + 353 + ], + "blocks": [ + { + "bbox": [ + 126, + 231, + 468, + 353 + ], + "lines": [ + { + "bbox": [ + 126, + 231, + 468, + 353 + ], + "spans": [ + { + "bbox": [ + 126, + 231, + 468, + 353 + ], + "type": "table", + "html": "
MethodN=10N=20N=50
Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓
iCaRL [29]65.2750.7431.2361.2043.7532.4056.0836.6236.59
UCIR [12]58.6643.3935.6758.1740.6337.7556.8637.0938.13
BiC [36]68.8053.5428.4466.4847.0229.3062.0941.0434.27
PODNet [8]58.0341.0541.4753.9735.0236.7051.1932.9940.42
DER w/o P [40]75.3665.2215.0274.0962.4823.5572.4159.0826.73
DER [40]74.6464.3515.7873.9862.5523.4772.0559.7626.59
DyTox [9]75.4762.1015.4375.1059.4121.6073.8957.2124.22
Ours79.1268.4012.1778.7665.2214.3976.9563.1218.34
", + "image_path": "97dd708fbab58bfb739ab602a430aa39b24f94592bf317399c340184a526d54d.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 354, + 542, + 365 + ], + "lines": [ + { + "bbox": [ + 47, + 354, + 542, + 365 + ], + "spans": [ + { + "bbox": [ + 47, + 354, + 542, + 365 + ], + "type": "text", + "content": "Table 1. Results on CIFAR-100 in average accuracy (%), last phase accuracy (%), and forgetting F (% on 10-, 20- and 50-task scenarios." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 384, + 287, + 445 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 384, + 287, + 445 + ], + "spans": [ + { + "bbox": [ + 46, + 384, + 287, + 445 + ], + "type": "text", + "content": "evaluate the 10-task setting for ImageNet-Full in which 100 new classes are included in each task. To measure the overall accuracy after all tasks during training, we report the average accuracy of learned tasks after each task and the accuracy of all tasks at the end of incremental learning." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "spans": [ + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "text", + "content": "Implementation details. We use the same network for all datasets. Models are trained from scratch to prevent data leakage with batch size of 1024 using Adam [14] with initial learning rate 1e-4 and cosine decay. The loss weights from Eq. 12 are set to " + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "inline_equation", + "content": "\\lambda_{cls} = 0.01" + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "inline_equation", + "content": "\\lambda_{rec} = 1.0" + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "inline_equation", + "content": "\\lambda_{det} = 1.0" + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "text", + "content": ". The masking ratios are set to " + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "inline_equation", + "content": "r = 0.75" + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "inline_equation", + "content": "r_1 = 0.75" + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "inline_equation", + "content": "r_2 = 0.4" + }, + { + "bbox": [ + 46, + 461, + 287, + 568 + ], + "type": "text", + "content": ". Each task is trained for 400 epochs. For exemplar-based methods from the literature, we store 20 samples for each classes (as is common practice)." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "type": "text", + "content": "We use 5 transformer blocks for the encoder and 1 for the decoder. All transformer blocks have an embedding dimension of 384 and 12 self-attention heads. This design differs from the original MAE as it is much more lightweight. We save image patches occupying the same amount of memory as other methods which store 20 full images per class. For example, we select 80 images and randomly save only " + }, + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "type": "inline_equation", + "content": "25\\%" + }, + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "type": "text", + "content": " patches from each using a masking ratio of 0.75 (thus only occupying the same space as 20 whole images). The detailed block is implemented with a 3-layer MLP keeping the dimension at 384. Further details about network architecture are given in the Supplementary Material." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 384, + 501, + 397 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 384, + 501, + 397 + ], + "spans": [ + { + "bbox": [ + 306, + 384, + 501, + 397 + ], + "type": "text", + "content": "4.2. Comparison with the state-of-the-art" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 403, + 545, + 475 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 403, + 545, + 475 + ], + "spans": [ + { + "bbox": [ + 304, + 403, + 545, + 475 + ], + "type": "text", + "content": "In this section we compare our approach with the state-of-the-art, including DER [40] and DyTox [9]. In all plots and tables, \"DER w/o P\" denotes DER [40] without pruning, therefore leading to more parameters being added across tasks. DyTox [9] also uses a transformer architecture and we use the official codebase to reproduce its results." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 486, + 546, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 486, + 546, + 605 + ], + "spans": [ + { + "bbox": [ + 304, + 486, + 546, + 605 + ], + "type": "text", + "content": "CIFAR-100. We report results in average accuracy (Avg), the accuracy after the last task (Last), and average forgetting (F) in Table 1. It is clear that under each setting our method outperforms others by a large margin. For longer task sequences, our bilateral MAE benefits from self-supervised reconstruction and richer replay data and it forgets much less compared to other methods. An overall accuracy curve is given in Fig. 4. Using the same amount of replay storage, our method outperforms DyTox by about " + }, + { + "bbox": [ + 304, + 486, + 546, + 605 + ], + "type": "inline_equation", + "content": "6\\%" + }, + { + "bbox": [ + 304, + 486, + 546, + 605 + ], + "type": "text", + "content": " in accuracy after the last task in all three scenarios." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 617, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 547, + 714 + ], + "type": "text", + "content": "ImageNet-Subset and ImageNet-Full. We report performance on ImageNet-Subset and ImageNet-Full in Tables 2 and 3, respectively. Our method outperforms DyTox [9] by " + }, + { + "bbox": [ + 304, + 617, + 547, + 714 + ], + "type": "inline_equation", + "content": "1.19\\%" + }, + { + "bbox": [ + 304, + 617, + 547, + 714 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 617, + 547, + 714 + ], + "type": "inline_equation", + "content": "2.53\\%" + }, + { + "bbox": [ + 304, + 617, + 547, + 714 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 617, + 547, + 714 + ], + "type": "inline_equation", + "content": "2.85\\%" + }, + { + "bbox": [ + 304, + 617, + 547, + 714 + ], + "type": "text", + "content": " absolute gain in accuracy after the last task on the 10-, 20- and 50-task settings, respectively. The higher average accuracy during each phase and lower forgetting also demonstrates the effectiveness of our method in alleviating forgetting. We also" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19108" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 95, + 79, + 226, + 213 + ], + "blocks": [ + { + "bbox": [ + 95, + 79, + 226, + 213 + ], + "lines": [ + { + "bbox": [ + 95, + 79, + 226, + 213 + ], + "spans": [ + { + "bbox": [ + 95, + 79, + 226, + 213 + ], + "type": "image", + "image_path": "8c43506805450191905fa3f0de49425a1f2d646825d336d0ea5cf76bf90a5a60.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 154, + 215, + 435, + 225 + ], + "lines": [ + { + "bbox": [ + 154, + 215, + 435, + 225 + ], + "spans": [ + { + "bbox": [ + 154, + 215, + 435, + 225 + ], + "type": "text", + "content": "Figure 5. Performance evolution over incremental tasks on ImageNet-Subset." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 228, + 79, + 360, + 213 + ], + "blocks": [ + { + "bbox": [ + 228, + 79, + 360, + 213 + ], + "lines": [ + { + "bbox": [ + 228, + 79, + 360, + 213 + ], + "spans": [ + { + "bbox": [ + 228, + 79, + 360, + 213 + ], + "type": "image", + "image_path": "237955116686f7b99a4bc37a0236ed4dd601132ccdfd27eb2002c69f86f616ec.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 364, + 80, + 494, + 213 + ], + "blocks": [ + { + "bbox": [ + 364, + 80, + 494, + 213 + ], + "lines": [ + { + "bbox": [ + 364, + 80, + 494, + 213 + ], + "spans": [ + { + "bbox": [ + 364, + 80, + 494, + 213 + ], + "type": "image", + "image_path": "a5efb5db626293b21b504615bccc1b091c4166aabd8dd45d6325c4132ab96a7f.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 126, + 234, + 468, + 332 + ], + "blocks": [ + { + "bbox": [ + 126, + 234, + 468, + 332 + ], + "lines": [ + { + "bbox": [ + 126, + 234, + 468, + 332 + ], + "spans": [ + { + "bbox": [ + 126, + 234, + 468, + 332 + ], + "type": "table", + "html": "
MethodN=10N=20N=50
Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓Avg ↑Last ↑F ↓
BiC [36]64.9655.0731.3259.4049.3534.7053.7544.5640.23
PODNet [8]63.4451.7535.6355.1145.3741.7051.7242.9444.65
DER w/o P [40]77.1866.7014.8672.7061.7420.7670.4458.8724.20
DER [40]76.1266.0615.0972.5661.5120.4669.7758.1925.35
DyTox [9]77.1569.1014.6673.1361.8717.3271.5160.0220.54
Ours79.5470.2912.0475.2064.4014.8974.4262.8717.22
", + "image_path": "b71d7ed80e1c09be6941f3f0720556b65dea8f83bd2862ffa47e3d69f7921548.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 72, + 361, + 263, + 459 + ], + "blocks": [ + { + "bbox": [ + 47, + 334, + 539, + 344 + ], + "lines": [ + { + "bbox": [ + 47, + 334, + 539, + 344 + ], + "spans": [ + { + "bbox": [ + 47, + 334, + 539, + 344 + ], + "type": "text", + "content": "Table 2. Results on ImageNet-Subset in average and last phase accuracy (%) and forgetting rate F (%) on 10-, 20- and 50-task scenarios." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 72, + 361, + 263, + 459 + ], + "lines": [ + { + "bbox": [ + 72, + 361, + 263, + 459 + ], + "spans": [ + { + "bbox": [ + 72, + 361, + 263, + 459 + ], + "type": "table", + "html": "
Methodtop-1top-5
Avg ↑Last ↑Avg ↑Last ↑
iCaRL [29]38.4022.7063.7044.00
Simple-DER66.6359.2485.6280.76
DER w/o P [40]68.8460.1688.1782.86
DER [40]66.7358.6287.0881.89
DyTox [9]71.2963.3488.5984.49
Ours74.7666.1591.4387.13
", + "image_path": "3eb2a878048386286fb3a30bd931b781a5e402e2a2d53247a0a1aa9cad4e09ab.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 494, + 287, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 494, + 287, + 567 + ], + "spans": [ + { + "bbox": [ + 46, + 494, + 287, + 567 + ], + "type": "text", + "content": "illustrate the performance evolution on ImageNet-Subset in Fig. 5. Our method has accuracy similar to DyTox in the first task, but in later tasks our method surpasses all others, especially for long task sequences. On the larger-scale ImageNet-Full, our Bilateral MAE significantly outperforms other methods by about " + }, + { + "bbox": [ + 46, + 494, + 287, + 567 + ], + "type": "inline_equation", + "content": "3\\%" + }, + { + "bbox": [ + 46, + 494, + 287, + 567 + ], + "type": "text", + "content": " in all metrics." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 578, + 141, + 590 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 578, + 141, + 590 + ], + "spans": [ + { + "bbox": [ + 47, + 578, + 141, + 590 + ], + "type": "text", + "content": "4.3. Ablation Study" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": "Ablations on different components. Our bilateral MAE consists of a self-supervised reconstruction task, generated data for replay, and a bilateral MAE branch for image- and embedding-level fusion. We ablate on these three factors in Table 4. These three major components in our method have different functions and they cooperate to boost performance compared with the baseline by about " + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "inline_equation", + "content": "6\\%" + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": ". We observe that: (a) More high-quality replay data has a direct contribution to the performance and masking ration of " + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "inline_equation", + "content": "r = 0.75" + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": " masking ratio yields " + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "inline_equation", + "content": "4 \\times" + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": " replay for the same storage cost as the" + } + ] + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 310, + 361, + 542, + 435 + ], + "blocks": [ + { + "bbox": [ + 47, + 460, + 264, + 471 + ], + "lines": [ + { + "bbox": [ + 47, + 460, + 264, + 471 + ], + "spans": [ + { + "bbox": [ + 47, + 460, + 264, + 471 + ], + "type": "text", + "content": "Table 3. Results on ImageNet-Full for 10 incremental tasks." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 310, + 361, + 542, + 435 + ], + "lines": [ + { + "bbox": [ + 310, + 361, + 542, + 435 + ], + "spans": [ + { + "bbox": [ + 310, + 361, + 542, + 435 + ], + "type": "table", + "html": "
MethodReplayReconstructionBilateralAvgLast
Baseline73.4062.31
Variants✓75.8864.35
✓✓77.4866.54
✓✓✓79.1268.40
", + "image_path": "6dd805524ab7c25061e80b3b3d74768e36ec6a332975f6690384c4d2d0d418c0.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + } + ], + "index": 11 + }, + { + "type": "table", + "bbox": [ + 360, + 502, + 493, + 575 + ], + "blocks": [ + { + "bbox": [ + 305, + 435, + 545, + 489 + ], + "lines": [ + { + "bbox": [ + 305, + 435, + 545, + 489 + ], + "spans": [ + { + "bbox": [ + 305, + 435, + 545, + 489 + ], + "type": "text", + "content": "Table 4. Ablative experiments on each component of our proposed method in the 10-task setting on CIFAR-100. Replay denotes using generated data from MAE for replay, Reconstruction means applying the self-supervised reconstruction loss, and Bilateral indicates introduction the detailed branch of the MAE." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 360, + 502, + 493, + 575 + ], + "lines": [ + { + "bbox": [ + 360, + 502, + 493, + 575 + ], + "spans": [ + { + "bbox": [ + 360, + 502, + 493, + 575 + ], + "type": "table", + "html": "
rData SourceAvgLast
0.60Generated77.5067.37
0.75Generated79.1268.40
0.90Generated77.1267.02
N/AReal79.5768.87
", + "image_path": "6aeffb04331f87e48c30f54bdb89c5b2ce55ac757b20059370c5e1166f668443.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_body" + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 575, + 547, + 631 + ], + "lines": [ + { + "bbox": [ + 304, + 575, + 547, + 631 + ], + "spans": [ + { + "bbox": [ + 304, + 575, + 547, + 631 + ], + "type": "text", + "content": "Table 5. Ablation on the masking ratio and quality of generated data. Experiments are on CIFAR-100 in the 10-task setting and we report top-1 accuracy in %. Data Source indicates whether replay is generated or real. In the last row we replay a selection of of real images equivalent in storage size to using " + }, + { + "bbox": [ + 304, + 575, + 547, + 631 + ], + "type": "inline_equation", + "content": "r_1 = 0.75" + }, + { + "bbox": [ + 304, + 575, + 547, + 631 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": "baseline. (b) The reconstruction loss serves as effective self-supervision and improves performance by about " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "2\\%" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": " in average accuracy. (c) The bilateral architecture works well by improving replay data generation quality and introducing image and embedding-level supervision." + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "19109" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 116, + 70, + 218, + 114 + ], + "blocks": [ + { + "bbox": [ + 116, + 70, + 218, + 114 + ], + "lines": [ + { + "bbox": [ + 116, + 70, + 218, + 114 + ], + "spans": [ + { + "bbox": [ + 116, + 70, + 218, + 114 + ], + "type": "table", + "html": "
DomainAvgLast
Spatial77.4565.93
Frequency79.1268.40
", + "image_path": "2bb1820b88ec807e3e807bf1627b6c4ae8f4e04eeffe944a541eb928c2bf69b5.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 46, + 114, + 287, + 159 + ], + "lines": [ + { + "bbox": [ + 46, + 114, + 287, + 159 + ], + "spans": [ + { + "bbox": [ + 46, + 114, + 287, + 159 + ], + "type": "text", + "content": "Table 6. Ablative experiments on the detailed head. Experiments are on CIFAR-100 in the 10-task setting and we report the top-1 accuracy in " + }, + { + "bbox": [ + 46, + 114, + 287, + 159 + ], + "type": "inline_equation", + "content": "\\%" + }, + { + "bbox": [ + 46, + 114, + 287, + 159 + ], + "type": "text", + "content": " . Domain denotes to which domain our loss is applied." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 78, + 182, + 246, + 312 + ], + "blocks": [ + { + "bbox": [ + 78, + 182, + 246, + 312 + ], + "lines": [ + { + "bbox": [ + 78, + 182, + 246, + 312 + ], + "spans": [ + { + "bbox": [ + 78, + 182, + 246, + 312 + ], + "type": "image", + "image_path": "fb7984d0f1b1d796a542cf6f2a72e951542fbace7c680a45ba54885eaa46427f.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 314, + 287, + 336 + ], + "lines": [ + { + "bbox": [ + 46, + 314, + 287, + 336 + ], + "spans": [ + { + "bbox": [ + 46, + 314, + 287, + 336 + ], + "type": "text", + "content": "Figure 6. Ablation on masking ratio " + }, + { + "bbox": [ + 46, + 314, + 287, + 336 + ], + "type": "inline_equation", + "content": "r_2" + }, + { + "bbox": [ + 46, + 314, + 287, + 336 + ], + "type": "text", + "content": " in " + }, + { + "bbox": [ + 46, + 314, + 287, + 336 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_t^{\\mathrm{det}}" + }, + { + "bbox": [ + 46, + 314, + 287, + 336 + ], + "type": "text", + "content": ". The other masking ratio " + }, + { + "bbox": [ + 46, + 314, + 287, + 336 + ], + "type": "inline_equation", + "content": "r_1" + }, + { + "bbox": [ + 46, + 314, + 287, + 336 + ], + "type": "text", + "content": " is set to " + }, + { + "bbox": [ + 46, + 314, + 287, + 336 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 46, + 314, + 287, + 336 + ], + "type": "text", + "content": " as the reference." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "spans": [ + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "text", + "content": "Masking ratio. A key parameter of MAE [11] is the masking ratio " + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "text", + "content": ". There is trade-off on " + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "text", + "content": ": too large " + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "text", + "content": " (e.g. 0.95) leads to poor reconstruction, which influences the quality of replay data and causes more serious forgetting. However, too small " + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "text", + "content": " yields a limited extra amount of replay data (e.g. we can afford only about " + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "inline_equation", + "content": "11\\%" + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "text", + "content": " extra replay data when " + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "text", + "content": " is 0.10). The results in Table 5 show that " + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "inline_equation", + "content": "r = 0.75" + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "text", + "content": " is a good trade-off for our bilateral MAE. To verify the quality of generated data for replay, also include results using original images for replay in place of generated ones. Results in rows 2 and 4 of Table 5 show that our method achieves good quality images with less than " + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "inline_equation", + "content": "0.5\\%" + }, + { + "bbox": [ + 46, + 355, + 288, + 511 + ], + "type": "text", + "content": " accuracy difference compared to replaying real images." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 522, + 287, + 606 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 522, + 287, + 606 + ], + "spans": [ + { + "bbox": [ + 46, + 522, + 287, + 606 + ], + "type": "text", + "content": "Frequency domain for the detailed loss. We implemented the detailed loss by converting embeddings from the spatial domain to the frequency domain. This aims to allow concentration on high-frequency information which matches the learning objective of the detailed MAE branch. As shown in Table 6, it is beneficial to make this conversion as it leads to a more than " + }, + { + "bbox": [ + 46, + 522, + 287, + 606 + ], + "type": "inline_equation", + "content": "2\\%" + }, + { + "bbox": [ + 46, + 522, + 287, + 606 + ], + "type": "text", + "content": " gain at the last task." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": "Ablation on " + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "inline_equation", + "content": "r_1" + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "inline_equation", + "content": "r_2" + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": " in the detailed loss. We set " + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "inline_equation", + "content": "r_1" + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": " to 0.75 for all these experiments as a reference and we vary " + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "inline_equation", + "content": "r_2" + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": " used for computing the ground truth of the detailed loss. The trade-off on " + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "inline_equation", + "content": "r_2" + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": " is that large " + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "inline_equation", + "content": "r_2" + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": " results in small differences between the reconstructed results from mask ratios " + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "inline_equation", + "content": "r_1" + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "inline_equation", + "content": "r_2" + }, + { + "bbox": [ + 46, + 618, + 288, + 713 + ], + "type": "text", + "content": " and therefore there is little information in the supervisory signal for the detailed loss and the impact of the detailed branch is reduced. On the other hand, too small" + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 306, + 70, + 545, + 133 + ], + "blocks": [ + { + "bbox": [ + 306, + 70, + 545, + 133 + ], + "lines": [ + { + "bbox": [ + 306, + 70, + 545, + 133 + ], + "spans": [ + { + "bbox": [ + 306, + 70, + 545, + 133 + ], + "type": "table", + "html": "
MethodParameters (M)Avg ↑Last ↑F ↓
DER w/o P112.2775.3665.2215.02
DyTox10.7375.4762.1015.43
Ours (MLP size = 1536)12.8979.1268.4012.17
Ours (MLP size = 768)9.3578.3667.5212.90
", + "image_path": "09e5ab1272eda62ae6a272a4d6f309c8dd7fe26e67dccc97a90a9b01de78bd9a.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 306, + 134, + 545, + 166 + ], + "lines": [ + { + "bbox": [ + 306, + 134, + 545, + 166 + ], + "spans": [ + { + "bbox": [ + 306, + 134, + 545, + 166 + ], + "type": "text", + "content": "Table 7. Comparison of model sizes. We compare two versions of our Bilateral MAE and competing models. Experiments were conducted on CIFAR-100 with 10 tasks." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 179, + 545, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 179, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 305, + 179, + 545, + 251 + ], + "type": "inline_equation", + "content": "r_2" + }, + { + "bbox": [ + 305, + 179, + 545, + 251 + ], + "type": "text", + "content": " (e.g. 0.10) maintains most of the residual part of reconstructed images from the main branch, which may bring weak supervision for the main branch and slow its training. We show results for a range of " + }, + { + "bbox": [ + 305, + 179, + 545, + 251 + ], + "type": "inline_equation", + "content": "r_2" + }, + { + "bbox": [ + 305, + 179, + 545, + 251 + ], + "type": "text", + "content": " values in Fig. 6. These results show that an " + }, + { + "bbox": [ + 305, + 179, + 545, + 251 + ], + "type": "inline_equation", + "content": "r_2" + }, + { + "bbox": [ + 305, + 179, + 545, + 251 + ], + "type": "text", + "content": " of about 0.40 is good for providing supervision to the detailed branch of our MAE." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 270, + 545, + 402 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 270, + 545, + 402 + ], + "spans": [ + { + "bbox": [ + 304, + 270, + 545, + 402 + ], + "type": "text", + "content": "Model and exemplar sizes. To compare the effectiveness of different methods, normally models with the same or similar number of parameters are used with an equal number of exemplars. In our approach, we adapt the original MAE to be more lightweight and the number of parameters is comparable to or even smaller than DyTox, as shown in Table 7 (last row). We set the masking ratio to " + }, + { + "bbox": [ + 304, + 270, + 545, + 402 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 304, + 270, + 545, + 402 + ], + "type": "text", + "content": " by default and save 80 exemplars per class, and therefore the storage size for both models and exemplars is similar since our stored image patches require exactly the same as baselines using only 20 exemplars." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 420, + 545, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 420, + 545, + 552 + ], + "spans": [ + { + "bbox": [ + 304, + 420, + 545, + 552 + ], + "type": "text", + "content": "Ablation on effective buffer size. In Table 8 we compare our method with Dytox using the same buffer size by masking input image patches in input to DyTox. All three rows use the same memory size for storing exemplars. Using 80 exemplars with masking ratio of " + }, + { + "bbox": [ + 304, + 420, + 545, + 552 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 304, + 420, + 545, + 552 + ], + "type": "text", + "content": ", DyTox (last row) achieves better performance than when using 20 full-image exemplars. It still performs worse than our approach, which shows that our performance gain does not simply come from the additional exemplars, but also from the integration of the MAE into our bilateral architecture with the Detailed Branch." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 571, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 571, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 571, + 545, + 715 + ], + "type": "text", + "content": "Reconstruction analysis. We illustrate results of image reconstruction in the 10-task setting on ImageNet-Subset in Fig. 7. Randomly selected images from tasks 1, 4, 7, and 10 are shown in the left column. Our bilateral MAE learns to reconstruct images in a task-agnostic way, which helps generate reasonable results for future tasks even before learning them. The detailed branch of our MAE learns to reconstruct high-frequency details complementary to the main branch. The results from the main branch sometimes lack sample-specific characteristics, but with the help of our proposed detailed branch the reconstructions are more accurate and provide better generated replay data." + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "19110" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 68, + 94, + 205 + ], + "blocks": [ + { + "bbox": [ + 50, + 68, + 94, + 205 + ], + "lines": [ + { + "bbox": [ + 50, + 68, + 94, + 205 + ], + "spans": [ + { + "bbox": [ + 50, + 68, + 94, + 205 + ], + "type": "image", + "image_path": "f675e55d9fe3a6e651045cf1210cdb24658bd690f4ef0c02952566650db44d49.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 63, + 206, + 88, + 215 + ], + "lines": [ + { + "bbox": [ + 63, + 206, + 88, + 215 + ], + "spans": [ + { + "bbox": [ + 63, + 206, + 88, + 215 + ], + "type": "text", + "content": "Image" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 105, + 70, + 206, + 206 + ], + "blocks": [ + { + "bbox": [ + 105, + 70, + 206, + 206 + ], + "lines": [ + { + "bbox": [ + 105, + 70, + 206, + 206 + ], + "spans": [ + { + "bbox": [ + 105, + 70, + 206, + 206 + ], + "type": "image", + "image_path": "65f60aeb255c7e0db0f32b7cef9073a7973463390543321387062664a20b02ae.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 136, + 207, + 160, + 215 + ], + "lines": [ + { + "bbox": [ + 136, + 207, + 160, + 215 + ], + "spans": [ + { + "bbox": [ + 136, + 207, + 160, + 215 + ], + "type": "text", + "content": "Task 1" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 217, + 70, + 318, + 206 + ], + "blocks": [ + { + "bbox": [ + 217, + 70, + 318, + 206 + ], + "lines": [ + { + "bbox": [ + 217, + 70, + 318, + 206 + ], + "spans": [ + { + "bbox": [ + 217, + 70, + 318, + 206 + ], + "type": "image", + "image_path": "193eca8f004189599fb6abbb5a0f02d15a3b91d93cdc5026f096319542fb6f8e.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 249, + 207, + 272, + 215 + ], + "lines": [ + { + "bbox": [ + 249, + 207, + 272, + 215 + ], + "spans": [ + { + "bbox": [ + 249, + 207, + 272, + 215 + ], + "type": "text", + "content": "Task 4" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 216, + 547, + 248 + ], + "lines": [ + { + "bbox": [ + 46, + 216, + 547, + 248 + ], + "spans": [ + { + "bbox": [ + 46, + 216, + 547, + 248 + ], + "type": "text", + "content": "Figure 7. Reconstructed images from ImageNet-Subset in the 10-task setting. Four original images were selected from tasks 1, 4, 6, and 10 and are shown on the left. In the remaining columns we show reconstructed images using our combined Bilateral MAE (left), only the detailed branch of our MAE (middle), and only the main branch of our MAE (right)." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 329, + 70, + 430, + 206 + ], + "blocks": [ + { + "bbox": [ + 329, + 70, + 430, + 206 + ], + "lines": [ + { + "bbox": [ + 329, + 70, + 430, + 206 + ], + "spans": [ + { + "bbox": [ + 329, + 70, + 430, + 206 + ], + "type": "image", + "image_path": "1f6ca61ea5470c0ed2b64db7413117da6ad32c2b92733cbe375b5e03332f9574.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 360, + 207, + 385, + 215 + ], + "lines": [ + { + "bbox": [ + 360, + 207, + 385, + 215 + ], + "spans": [ + { + "bbox": [ + 360, + 207, + 385, + 215 + ], + "type": "text", + "content": "Task 7" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 441, + 70, + 542, + 206 + ], + "blocks": [ + { + "bbox": [ + 441, + 70, + 542, + 206 + ], + "lines": [ + { + "bbox": [ + 441, + 70, + 542, + 206 + ], + "spans": [ + { + "bbox": [ + 441, + 70, + 542, + 206 + ], + "type": "image", + "image_path": "4f90a44ff2b2e59a0a65e4282a3f2fcc955b971c9f8c02588fda54fde540918d.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 470, + 207, + 500, + 215 + ], + "lines": [ + { + "bbox": [ + 470, + 207, + 500, + 215 + ], + "spans": [ + { + "bbox": [ + 470, + 207, + 500, + 215 + ], + "type": "text", + "content": "Task 10" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 48, + 266, + 287, + 316 + ], + "blocks": [ + { + "bbox": [ + 48, + 266, + 287, + 316 + ], + "lines": [ + { + "bbox": [ + 48, + 266, + 287, + 316 + ], + "spans": [ + { + "bbox": [ + 48, + 266, + 287, + 316 + ], + "type": "table", + "html": "
MethodBufferMemory size25% PatchesImagesAcc(%)
Ours801x✓68.40
DyTox201x✓62.10
DyToxt801x✓65.46
", + "image_path": "ff3b038305248ba574efeaee4e1edb6bb142bd3137cdaeadf58628c20bbe0a82.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 47, + 316, + 288, + 361 + ], + "lines": [ + { + "bbox": [ + 47, + 316, + 288, + 361 + ], + "spans": [ + { + "bbox": [ + 47, + 316, + 288, + 361 + ], + "type": "text", + "content": "Table 8. Ablation on effective buffer size with equal memory usage. Dytox† represents applying a mask ratio " + }, + { + "bbox": [ + 47, + 316, + 288, + 361 + ], + "type": "inline_equation", + "content": "r = 75\\%" + }, + { + "bbox": [ + 47, + 316, + 288, + 361 + ], + "type": "text", + "content": " directly to stored image exemplars in order to have the same number of exemplars and storage size for DyTox as in our setting." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 50, + 367, + 285, + 506 + ], + "blocks": [ + { + "bbox": [ + 50, + 367, + 285, + 506 + ], + "lines": [ + { + "bbox": [ + 50, + 367, + 285, + 506 + ], + "spans": [ + { + "bbox": [ + 50, + 367, + 285, + 506 + ], + "type": "image", + "image_path": "ed239fd20b7b53c839b8407fbdc3c4616a1fcfa81bd80bcbe5c1d4637aa71df5.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 77, + 517, + 256, + 529 + ], + "lines": [ + { + "bbox": [ + 77, + 517, + 256, + 529 + ], + "spans": [ + { + "bbox": [ + 77, + 517, + 256, + 529 + ], + "type": "text", + "content": "Figure 8. Comparison of feature space density " + }, + { + "bbox": [ + 77, + 517, + 256, + 529 + ], + "type": "inline_equation", + "content": "\\pi" + }, + { + "bbox": [ + 77, + 517, + 256, + 529 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 532, + 287, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 532, + 287, + 653 + ], + "spans": [ + { + "bbox": [ + 46, + 532, + 287, + 653 + ], + "type": "text", + "content": "More generalizable representations help CIL. We calculated the feature space density metric [32] for different methods following PASS [46]: " + }, + { + "bbox": [ + 46, + 532, + 287, + 653 + ], + "type": "inline_equation", + "content": "\\pi = \\pi_{intra} / \\pi_{inter}" + }, + { + "bbox": [ + 46, + 532, + 287, + 653 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 532, + 287, + 653 + ], + "type": "inline_equation", + "content": "\\pi_{intra}" + }, + { + "bbox": [ + 46, + 532, + 287, + 653 + ], + "type": "text", + "content": " denotes the average cosine similarity within the same class and " + }, + { + "bbox": [ + 46, + 532, + 287, + 653 + ], + "type": "inline_equation", + "content": "\\pi_{inter}" + }, + { + "bbox": [ + 46, + 532, + 287, + 653 + ], + "type": "text", + "content": " denotes the one within different classes. Increased feature space density is associated with stronger generalization under data shift [46]. We then compared feature space density after training all tasks, as shown in Figure 8 above. It is clear that Ours yields significantly higher density than other methods." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "content": "Ablation with other efficient replay methods. We compared the replay samples generated by MAE in our framework with a variety of memory-efficient methods based on latent replay [19], synthesized exemplars [20], down-" + } + ] + } + ], + "index": 16 + }, + { + "type": "table", + "bbox": [ + 309, + 266, + 544, + 355 + ], + "blocks": [ + { + "bbox": [ + 309, + 266, + 544, + 355 + ], + "lines": [ + { + "bbox": [ + 309, + 266, + 544, + 355 + ], + "spans": [ + { + "bbox": [ + 309, + 266, + 544, + 355 + ], + "type": "table", + "html": "
MetricMemoryAvg↑Last↑
Latent replay (CVPRW'20) [19]-62.4451.30
MCIL (CVPR'20) [20]6063.2553.12
Down-scaled (TNNLS'21) [45]6067.0455.40
JPEG compression (ICLR'22) [34]6072.3461.32
CIM (CVPR'23) [22]6075.3063.05
Ours6079.1268.40
", + "image_path": "4af50a43e2986b6e720e59f853c6c6efe1aff3f34b29046ed14ee2fc54cb863e.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 306, + 355, + 545, + 388 + ], + "lines": [ + { + "bbox": [ + 306, + 355, + 545, + 388 + ], + "spans": [ + { + "bbox": [ + 306, + 355, + 545, + 388 + ], + "type": "text", + "content": "Table 9. Comparison of our bilateral MAE framework with other memory-efficient methods on the CIFAR-100 10-task setting. Memory indicates the required storage space per class (in KB)." + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 408, + 545, + 469 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 408, + 545, + 469 + ], + "spans": [ + { + "bbox": [ + 305, + 408, + 545, + 469 + ], + "type": "text", + "content": "scaling [45], JPEG image compression [34], and CIM [22] (foreground extraction and background compression). All these methods use the same amount of storage (except Latent Replay uses a GAN with 4.5M parameters), while our approach achieves consistently higher performance." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 491, + 384, + 502 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 491, + 384, + 502 + ], + "spans": [ + { + "bbox": [ + 306, + 491, + 384, + 502 + ], + "type": "text", + "content": "5. Conclusions" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 514, + 545, + 624 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 514, + 545, + 624 + ], + "spans": [ + { + "bbox": [ + 304, + 514, + 545, + 624 + ], + "type": "text", + "content": "In this work, we demonstrate that Masked Autoencoders are efficient incremental learners. Our approach stores random image patches as exemplars and it can reconstruct high-quality images from only partial information for replay. Furthermore, we propose a novel bilateral MAE architecture which further improves embedding diversity and reconstruction quality. Our Bilateral MAE approach significantly outperforms previous state-of-the-art methods for the same exemplar storage cost." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 653, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 715 + ], + "type": "text", + "content": "Acknowledgements This work is funded by NSFC (NO. 62225604, 62206135), and the Fundamental Research Funds for the Central Universities (Nankai University, 070-63233085). Computation is supported by the Supercomputing Center of Nankai University." + } + ] + } + ], + "index": 22 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19111" + } + ] + } + ], + "index": 23 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 286, + 712 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 53, + 91, + 286, + 124 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 286, + 124 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 286, + 124 + ], + "type": "text", + "content": "[1] Rahaf Aljundi, Punarjay Chakravarty, and Tinne Tuytelaars. Expert gate: Lifelong learning with a network of experts. In IEEE Conf. Comput. Vis. Pattern Recog., 2017. 1" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 126, + 286, + 168 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 126, + 286, + 168 + ], + "spans": [ + { + "bbox": [ + 53, + 126, + 286, + 168 + ], + "type": "text", + "content": "[2] Eden Belouadah, Adrian Popescu, and Ioannis Kanellos. A comprehensive study of class incremental learning algorithms for visual tasks. Neural Networks, 135:38-54, 2021. 1, 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 171, + 286, + 204 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 171, + 286, + 204 + ], + "spans": [ + { + "bbox": [ + 53, + 171, + 286, + 204 + ], + "type": "text", + "content": "[3] Arslan Chaudhry, Marc'Aurelio Ranzato, Marcus Rohrbach, and Mohamed Elhoseiny. Efficient lifelong learning with a gem. In Int. Conf. Learn. Represent., 2019. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 205, + 286, + 249 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 205, + 286, + 249 + ], + "spans": [ + { + "bbox": [ + 53, + 205, + 286, + 249 + ], + "type": "text", + "content": "[4] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning of visual representations. In International conference on machine learning, pages 1597-1607. PMLR, 2020. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 251, + 286, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 251, + 286, + 293 + ], + "spans": [ + { + "bbox": [ + 53, + 251, + 286, + 293 + ], + "type": "text", + "content": "[5] Matthias Delange, Rahaf Aljundi, Marc Masana, Sarah Parisot, Xu Jia, Ales Leonardis, Greg Slabaugh, and Tinne Tuytelaars. A continual learning survey: Defying forgetting in classification tasks. TPAMI, 2021. 1, 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 296, + 286, + 338 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 296, + 286, + 338 + ], + "spans": [ + { + "bbox": [ + 53, + 296, + 286, + 338 + ], + "type": "text", + "content": "[6] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In IEEE Conf. Comput. Vis. Pattern Recog., 2009. 4" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 341, + 286, + 373 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 341, + 286, + 373 + ], + "spans": [ + { + "bbox": [ + 53, + 341, + 286, + 373 + ], + "type": "text", + "content": "[7] Carl Doersch, Abhinav Gupta, and Alexei A Efros. Unsupervised visual representation learning by context prediction. In Int. Conf. Comput. Vis., 2015. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 375, + 286, + 418 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 375, + 286, + 418 + ], + "spans": [ + { + "bbox": [ + 53, + 375, + 286, + 418 + ], + "type": "text", + "content": "[8] Arthur Douillard, Matthieu Cord, Charles Ollion, Thomas Robert, and Eduardo Valle. Podnet: Pooled outputs distillation for small-tasks incremental learning. In Eur. Conf. Comput. Vis., 2020. 2, 5, 6" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 420, + 286, + 464 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 420, + 286, + 464 + ], + "spans": [ + { + "bbox": [ + 53, + 420, + 286, + 464 + ], + "type": "text", + "content": "[9] Arthur Douillard, Alexandre Rame, Guillaume Couairon, and Matthieu Cord. Dytox: Transformers for continual learning with dynamic token expansion. In IEEE Conf. Comput. Vis. Pattern Recog., 2022. 5, 6" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 465, + 286, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 465, + 286, + 498 + ], + "spans": [ + { + "bbox": [ + 48, + 465, + 286, + 498 + ], + "type": "text", + "content": "[10] Spyros Gidaris, Praveer Singh, and Nikos Komodakis. Unsupervised representation learning by predicting image rotations. In Int. Conf. Learn. Represent., 2018. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 499, + 286, + 542 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 499, + 286, + 542 + ], + "spans": [ + { + "bbox": [ + 48, + 499, + 286, + 542 + ], + "type": "text", + "content": "[11] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In IEEE Conf. Comput. Vis. Pattern Recog., 2022. 1, 2, 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 544, + 286, + 587 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 544, + 286, + 587 + ], + "spans": [ + { + "bbox": [ + 48, + 544, + 286, + 587 + ], + "type": "text", + "content": "[12] Saihui Hou, Xinyu Pan, Chen Change Loy, Zilei Wang, and Dahua Lin. Learning a unified classifier incrementally via rebalancing. In IEEE Conf. Comput. Vis. Pattern Recog., 2019. 5" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 590, + 286, + 611 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 590, + 286, + 611 + ], + "spans": [ + { + "bbox": [ + 48, + 590, + 286, + 611 + ], + "type": "text", + "content": "[13] David Isele and Akansel Cosgun. Selective experience replay for lifelong learning. In AAAI, 2018. 1" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 613, + 286, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 613, + 286, + 644 + ], + "spans": [ + { + "bbox": [ + 48, + 613, + 286, + 644 + ], + "type": "text", + "content": "[14] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. In Int. Conf. Learn. Represent., 2015. 5" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 647, + 286, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 286, + 712 + ], + "type": "text", + "content": "[15] James Kirkpatrick, Razvan Pascanu, Neil Rabinowitz, Joel Veness, Guillaume Desjardins, Andrei A Rusu, Kieran Milan, John Quan, Tiago Ramalho, Agnieszka Grabska-Barwinska, et al. Overcoming catastrophic forgetting in neural networks. Proceedings of the national academy of sciences, 2017. 1, 2" + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 34, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 95 + ], + "type": "text", + "content": "[16] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images, 2009. 4" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 96, + 545, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 96, + 545, + 117 + ], + "spans": [ + { + "bbox": [ + 307, + 96, + 545, + 117 + ], + "type": "text", + "content": "[17] Zhizhong Li and Derek Hoiem. Learning without forgetting. In Eur. Conf. Comput. Vis., 2016. 1, 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 118, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 118, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 308, + 118, + 545, + 150 + ], + "type": "text", + "content": "[18] Feng Liang, Yangguang Li, and Diana Marculescu. Supmae: Supervised masked autoencoders are efficient vision learners. arXiv preprint arXiv:2205.14540, 2022. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 152, + 545, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 152, + 545, + 205 + ], + "spans": [ + { + "bbox": [ + 308, + 152, + 545, + 205 + ], + "type": "text", + "content": "[19] Xialei Liu, Chenshen Wu, Mikel Menta, Luis Herranz, Bogdan Raducanu, Andrew D Bagdanov, Shangling Jui, and Joost van de Weijer. Generative feature replay for class incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog. Worksh., 2020. 8" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 206, + 545, + 249 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 206, + 545, + 249 + ], + "spans": [ + { + "bbox": [ + 308, + 206, + 545, + 249 + ], + "type": "text", + "content": "[20] Yaoyao Liu, Yuting Su, An-An Liu, Bernt Schiele, and Qianru Sun. Mnemonics training: Multi-class incremental learning without forgetting. In IEEE Conf. Comput. Vis. Pattern Recog., pages 12245-12254, 2020. 8" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 251, + 545, + 282 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 251, + 545, + 282 + ], + "spans": [ + { + "bbox": [ + 308, + 251, + 545, + 282 + ], + "type": "text", + "content": "[21] David Lopez-Paz and Marc'Aurelio Ranzato. Gradient episodic memory for continual learning. Adv. Neural Inform. Process. Syst., 2017. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 284, + 545, + 327 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 284, + 545, + 327 + ], + "spans": [ + { + "bbox": [ + 308, + 284, + 545, + 327 + ], + "type": "text", + "content": "[22] Zilin Luo, Yaoyao Liu, Bernt Schiele, and Qianru Sun. Class-incremental exemplar compression for class-incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., pages 11371-11380, 2023. 8" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 328, + 545, + 360 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 328, + 545, + 360 + ], + "spans": [ + { + "bbox": [ + 308, + 328, + 545, + 360 + ], + "type": "text", + "content": "[23] Arun Mallya, Dillon Davis, and Svetlana Lazebnik. Piggyback: Adapting a single network to multiple tasks by learning to mask weights. In Eur. Conf. Comput. Vis., 2018. 1" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 361, + 545, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 361, + 545, + 392 + ], + "spans": [ + { + "bbox": [ + 308, + 361, + 545, + 392 + ], + "type": "text", + "content": "[24] Arun Mallya and Svetlana Lazebnik. Packnet: Adding multiple tasks to a single network by iterative pruning. In IEEE Conf. Comput. Vis. Pattern Recog., 2018. 1, 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 394, + 545, + 447 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 394, + 545, + 447 + ], + "spans": [ + { + "bbox": [ + 308, + 394, + 545, + 447 + ], + "type": "text", + "content": "[25] Marc Masana, Xialei Liu, Barttomiej Twardowski, Mikel Menta, Andrew D. Bagdanov, and Joost van de Weijer. Class-incremental learning: Survey and performance evaluation on image classification. IEEE Trans. Pattern Anal. Mach. Intell., 2022. 1" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 449, + 545, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 449, + 545, + 491 + ], + "spans": [ + { + "bbox": [ + 308, + 449, + 545, + 491 + ], + "type": "text", + "content": "[26] Michael McCloskey and Neal J Cohen. Catastrophic interference in connectionist networks: The sequential learning problem. In *Psychology of learning and motivation*. Elsevier, 1989. 1" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 494, + 545, + 525 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 494, + 545, + 525 + ], + "spans": [ + { + "bbox": [ + 308, + 494, + 545, + 525 + ], + "type": "text", + "content": "[27] Mehdi Noroozi and Paolo Favaro. Unsupervised learning of visual representations by solving jigsaw puzzles. In Eur. Conf. Comput. Vis., 2016. 2" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 527, + 545, + 557 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 527, + 545, + 557 + ], + "spans": [ + { + "bbox": [ + 308, + 527, + 545, + 557 + ], + "type": "text", + "content": "[28] Quang Pham, Chenghao Liu, and Steven Hoi. Dualnet: Continual learning, fast and slow. Adv. Neural Inform. Process. Syst., 2021. 2" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 308, + 559, + 545, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 559, + 545, + 602 + ], + "spans": [ + { + "bbox": [ + 308, + 559, + 545, + 602 + ], + "type": "text", + "content": "[29] Sylvestre-Alvise Rebuffi, Alexander Kolesnikov, Georg Sperl, and Christoph H Lampert. icarl: Incremental classifier and representation learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2017. 1, 2, 5, 6" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 308, + 604, + 545, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 604, + 545, + 646 + ], + "spans": [ + { + "bbox": [ + 308, + 604, + 545, + 646 + ], + "type": "text", + "content": "[30] Matthew Riemer, Ignacio Cases, Robert Ajemian, Miao Liu, Irina Rish, Yuhai Tu, and Gerald Tesauro. Learning to learn without forgetting by maximizing transfer and minimizing interference. In Int. Conf. Learn. Represent., 2019. 2" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 308, + 647, + 545, + 680 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 647, + 545, + 680 + ], + "spans": [ + { + "bbox": [ + 308, + 647, + 545, + 680 + ], + "type": "text", + "content": "[31] David Rolnick, Arun Ahuja, Jonathan Schwarz, Timothy Lillicrap, and Gregory Wayne. Experience replay for continual learning. Adv. Neural Inform. Process. Syst., 2019. 1" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 308, + 681, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 681, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 681, + 545, + 713 + ], + "type": "text", + "content": "[32] Karsten Roth, Timo Milbich, Samarth Sinha, Prateek Gupta, Bjorn Ommer, and Joseph Paul Cohen. Revisiting training strategies and generalization performance in deep metric" + } + ] + } + ], + "index": 33 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19112" + } + ] + } + ], + "index": 35 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 700 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 66, + 72, + 286, + 94 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 286, + 94 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 286, + 94 + ], + "type": "text", + "content": "learning. In Int. Mach. Learn., pages 8242-8252. PMLR, 2020. 8" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 140 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 140 + ], + "type": "text", + "content": "[33] James Smith, Yen-Chang Hsu, Jonathan Balloch, Yilin Shen, Hongxia Jin, and Zsolt Kira. Always be dreaming: A new approach for data-free class-incremental learning. In Int. Conf. Comput. Vis., 2021. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 141, + 287, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 141, + 287, + 194 + ], + "spans": [ + { + "bbox": [ + 48, + 141, + 287, + 194 + ], + "type": "text", + "content": "[34] Liyuan Wang, Xingxing Zhang, Kuo Yang, Longhui Yu, Chongxuan Li, Lanqing Hong, Shifeng Zhang, Zhenguo Li, Yi Zhong, and Jun Zhu. Memory replay with data compression for continual learning. In Int. Conf. Learn. Represent., 2022. 8" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 197, + 287, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 197, + 287, + 239 + ], + "spans": [ + { + "bbox": [ + 48, + 197, + 287, + 239 + ], + "type": "text", + "content": "[35] Chenshen Wu, Luis Herranz, Xialei Liu, Joost van de Weijer, Bogdan Raducanu, et al. Memory replay gans: Learning to generate new categories without forgetting. Adv. Neural Inform. Process. Syst., 2018. 1, 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 241, + 287, + 284 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 241, + 287, + 284 + ], + "spans": [ + { + "bbox": [ + 48, + 241, + 287, + 284 + ], + "type": "text", + "content": "[36] Yue Wu, Yinpeng Chen, Lijuan Wang, Yuancheng Ye, Zicheng Liu, Yandong Guo, and Yun Fu. Large scale incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2019. 2, 5, 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 286, + 287, + 328 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 286, + 287, + 328 + ], + "spans": [ + { + "bbox": [ + 48, + 286, + 287, + 328 + ], + "type": "text", + "content": "[37] Zhirong Wu, Yuanjun Xiong, Stella X Yu, and Dahua Lin. Unsupervised feature learning via non-parametric instance discrimination. In IEEE Conf. Comput. Vis. Pattern Recog., 2018. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 331, + 287, + 363 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 331, + 287, + 363 + ], + "spans": [ + { + "bbox": [ + 48, + 331, + 287, + 363 + ], + "type": "text", + "content": "[38] Ye Xiang, Ying Fu, Pan Ji, and Hua Huang. Incremental learning using conditional adversarial networks. In Int. Conf. Comput. Vis., 2019. 1" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 365, + 286, + 386 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 365, + 286, + 386 + ], + "spans": [ + { + "bbox": [ + 48, + 365, + 286, + 386 + ], + "type": "text", + "content": "[39] Ju Xu and Zhanxing Zhu. Reinforced continual learning. Adv. Neural Inform. Process. Syst., 2018. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 388, + 287, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 388, + 287, + 430 + ], + "spans": [ + { + "bbox": [ + 48, + 388, + 287, + 430 + ], + "type": "text", + "content": "[40] Shipeng Yan, Jiangwei Xie, and Xuming He. Der: Dynamically expandable representation for class incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2021. 5, 6" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 433, + 287, + 485 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 433, + 287, + 485 + ], + "spans": [ + { + "bbox": [ + 48, + 433, + 287, + 485 + ], + "type": "text", + "content": "[41] Hongxu Yin, Pavlo Molchanov, Jose M Alvarez, Zhizhong Li, Arun Mallya, Derek Hoiem, Niraj K Jha, and Jan Kautz. Dreaming to distill: Data-free knowledge transfer via deep-inversion. In IEEE Conf. Comput. Vis. Pattern Recog., 2020. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 488, + 287, + 532 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 488, + 287, + 532 + ], + "spans": [ + { + "bbox": [ + 48, + 488, + 287, + 532 + ], + "type": "text", + "content": "[42] Jure Zbontar, Li Jing, Ishan Misra, Yann LeCun, and Stéphane Deny. Barlow twins: Self-supervised learning via redundancy reduction. In International Conference on Machine Learning, pages 12310-12320. PMLR, 2021. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 533, + 287, + 576 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 533, + 287, + 576 + ], + "spans": [ + { + "bbox": [ + 48, + 533, + 287, + 576 + ], + "type": "text", + "content": "[43] Mengyao Zhai, Lei Chen, Frederick Tung, Jiawei He, Megha Nawhal, and Greg Mori. Lifelong gan: Continual learning for conditional image generation. In Int. Conf. Comput. Vis., 2019. 1" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 578, + 287, + 620 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 578, + 287, + 620 + ], + "spans": [ + { + "bbox": [ + 48, + 578, + 287, + 620 + ], + "type": "text", + "content": "[44] Junting Zhang, Jie Zhang, Shalini Ghosh, Dawei Li, Serafettin Tasci, Larry Heck, Heming Zhang, and C-C Jay Kuo. Class-incremental learning via deep model consolidation. In WACV, 2020. 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 623, + 287, + 655 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 623, + 287, + 655 + ], + "spans": [ + { + "bbox": [ + 48, + 623, + 287, + 655 + ], + "type": "text", + "content": "[45] Hanbin Zhao, Hui Wang, Yongjian Fu, Fei Wu, and Xi Li. Memory-efficient class-incremental learning for image classification. TNNLS, 33(10):5966-5977, 2021. 8" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 657, + 287, + 700 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 657, + 287, + 700 + ], + "spans": [ + { + "bbox": [ + 48, + 657, + 287, + 700 + ], + "type": "text", + "content": "[46] Fei Zhu, Xu-Yao Zhang, Chuang Wang, Fei Yin, and ChengLin Liu. Prototype augmentation and self-supervision for incremental learning. In IEEE Conf. Comput. Vis. Pattern Recog., 2021. 2, 8" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19113" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/a412e570-59ba-43e9-aea5-2909edb799b1_content_list.json b/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/a412e570-59ba-43e9-aea5-2909edb799b1_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..f29d8db16dc678179335785cfc3b6f00624ce27f --- /dev/null +++ b/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/a412e570-59ba-43e9-aea5-2909edb799b1_content_list.json @@ -0,0 +1,1568 @@ +[ + { + "type": "text", + "text": "Masked Diffusion Transformer is a Strong Image Synthesizer", + "text_level": 1, + "bbox": [ + 174, + 161, + 794, + 181 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Shanghua Gao $^{1,2}$ * Pan Zhou $^{2\\dagger}$ Ming-Ming Cheng $^{1\\dagger}$ Shuicheng Yan $^{2}$ $^{1}$ Nankai University Sea AI Lab", + "bbox": [ + 184, + 206, + 781, + 239 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{shanghuagao, shuicheng.yan} $@$ gmail.com zhoupan@sea.com cmm@nankai.edu.cn", + "bbox": [ + 171, + 242, + 796, + 256 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 288, + 312, + 302 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Despite its success in image synthesis, we observe that diffusion probabilistic models (DPMs) often lack contextual reasoning ability to learn the relations among object parts in an image, leading to a slow learning process. To solve this issue, we propose a Masked Diffusion Transformer (MDT) that introduces a mask latent modeling scheme to explicitly enhance the DPMs' ability to contextual relation learning among object semantic parts in an image. During training, MDT operates in the latent space to mask certain tokens. Then, an asymmetric masking diffusion transformer is designed to predict masked tokens from unmasked ones while maintaining the diffusion generation process. Our MDT can reconstruct the full information of an image from its incomplete contextual input, thus enabling it to learn the associated relations among image tokens. Experimental results show that MDT achieves superior image synthesis performance, e.g., a new SOTA FID score in the ImageNet data set, and has about $3 \\times$ faster learning speed than the previous SOTA DiT. The source code is released at https://github.com/sail-sg/MDT.", + "bbox": [ + 75, + 317, + 473, + 593 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 77, + 618, + 208, + 631 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Diffusion probabilistic models (DPMs) [11, 38] have been at the forefront of recent advances in image-level generative models, often surpassing the previously state-of-the-art (SOTA) generative adversarial networks (GANs) [4, 17, 37, 54]. Additionally, DPMs have demonstrated their success in numerous other applications, including text-to-image generation [38] and speech generation [24]. DPMs adopt a time-inverted Stochastic Differential Equation (SDE) to gradually map a Gaussian noise into a sample by multiple time steps, with each step corresponding to a network evaluation. In practice, generating a sample is time-consuming due to the thousands of time steps required for the SDE to converge. To address this issue, various generation sampling strategies [21, 32, 41] have been proposed to accelerate the in", + "bbox": [ + 75, + 641, + 470, + 836 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/f524cb6073718353db51791e480953b774e33c6eff34cb0e76e746fc172e8546.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 504, + 286, + 887, + 415 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/692b33b1879e9acc77fc48be6ad5d988561d14ba97d940bbb93f0ecac71efbd1.jpg", + "image_caption": [ + "Figure 1. Top: Visual examples of MDT/DiT [35]. Down: learning progress comparison between DiT and MDT w.r.t. training steps/time on $8 \\times \\mathrm{A}100$ GPUs. MDT has about $3 \\times$ faster learning speed than DiT while achieving superior FID scores." + ], + "image_footnote": [], + "bbox": [ + 485, + 423, + 690, + 553 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/1ac70bcc7407644542356c9d71aaefdcde249f163e75ee8359b872e0ca7b7063.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 697, + 423, + 889, + 552 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "ference speed. Nevertheless, improving the training speed of DPMs is less explored but highly desired. Training of DPMs also unavoidably requires a large number of time steps to ensure the convergence of SDEs, making it very computationally expensive, especially in this era where large-scale models [11,35] and data [9,14,44] are often used to improve generation performance.", + "bbox": [ + 497, + 630, + 894, + 726 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In this work, we first observe that DPMs often struggle to learn the associated relations among object parts in an image. This leads to its slow learning process during training. Specifically, as illustrated in Fig. 1, the classical DPM, DDPM [21] with DiT [35] as the backbone, has learned the shape of a dog at the $50\\mathrm{k}$ -th training step, then learns its one eye and mouth until at the $200\\mathrm{k}$ -th step while missing another eye. Also, the relative position of two ears is not very accurate, even at the $300\\mathrm{k}$ -th step. This learning process reveals that DPMs fail to learn the associated relations", + "bbox": [ + 497, + 726, + 895, + 866 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 129, + 49, + 200, + 85 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 253, + 48, + 789, + 86 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*This work was done while S. Gao was a research intern at Sea AI Lab.", + "bbox": [ + 92, + 842, + 467, + 853 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "† Pan Zhou and Ming-Ming Cheng are joint corresponding authors.", + "bbox": [ + 95, + 853, + 448, + 866 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "23164", + "bbox": [ + 463, + 887, + 505, + 897 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "among semantic parts and independently learn each semantic part. The reason behind this phenomenon is that DPMs maximize the log probability of real data by minimizing the per-pixel prediction loss, which ignores the associated relations among object parts in an image, thus resulting in their slow learning progress.", + "bbox": [ + 75, + 125, + 470, + 209 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Inspired by the above observation, we propose an effective Masked Diffusion Transformer (MDT) to improve the training efficiency of DPMs. MDT proposes a mask latent modeling scheme designed for transformer-based DPMs to explicitly enhance contextual learning ability and improve the associated relation learning among semantic parts in an image. Specifically, following [35, 38], MDT operates the diffusion process in the latent space to save computational costs. It masks certain image tokens and designs an asymmetric diffusion transformer structure to predict masked tokens from unmasked ones in a diffusion generation manner. To this end, the asymmetric structure contains an encoder, a side-interpolyter, and a decoder. The encoder and decoder modify the transformer block in DiT [35] by inserting global and local token position information to help predict masked tokens. The encoder only processes unmasked tokens during training handling all tokens during inference, as there are no masks. So to ensure the decoder always processes all tokens for training prediction or inference generation, a side-interpolyter implemented by a small network aims to predict masked tokens from encoder output during training, and it is removed during inference.", + "bbox": [ + 75, + 210, + 473, + 514 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "With the masking latent modeling scheme, our MDT can reconstruct the full information of an image from its contextual incomplete input, learning the associated relations among semantic parts in an image. As shown in Fig. 1, MDT typically generates two eyes of the dog at almost the same training steps, indicating that it correctly learns the associated semantics of an image by utilizing the mask latent modeling scheme. In contrast, DiT [35] cannot easily synthesize a dog with the correct semantic part relations. This comparison shows MDT's superior relation modeling and faster learning ability over DiT. Experimental results demonstrate that MDT achieves superior performance on the image synthesis task, and set the new SOTA on class-conditional image synthesis on the ImageNet dataset, as shown in Fig. 2 and Tab. 2. MDT also enjoys about $3 \\times$ faster learning progress during training than the SOTA DPMs, namely DiT, as demonstrated by Fig. 1 and Tab. 1. We hope our work can inspire more work on speeding up the diffusion training process with unified representation learning.", + "bbox": [ + 75, + 516, + 470, + 779 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The main contributions are summarised as follows:", + "bbox": [ + 95, + 781, + 433, + 794 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "- By introducing an effective mask latent modeling scheme, we proposed a masked diffusion transformer method, which, for the first time, explicitly enhances the contextual learning ability of DPMs.", + "bbox": [ + 95, + 809, + 468, + 866 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/54dd6a9f8830f3ff6229ac95d07991936d6dddf3890485b5816fc0dedd52c5b9.jpg", + "image_caption": [ + "Figure 2. Visualization of images generated by the MDT-XL/2." + ], + "image_footnote": [], + "bbox": [ + 507, + 123, + 885, + 323 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "- Experiments show that our method better synthesis images while using much less training time than SOTA.", + "bbox": [ + 517, + 359, + 892, + 385 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related works", + "text_level": 1, + "bbox": [ + 499, + 406, + 643, + 420 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Diffusion Probabilistic models", + "text_level": 1, + "bbox": [ + 499, + 428, + 766, + 441 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Diffusion probabilistic model (DPM) [11,21], also known as score-based model [48,49], is a competitive image synthesis approach. DPMs begin by using an evolving Stochastic Differential Equation (SDE) to gradually add Gaussian noise into real data, transforming a complex data distribution into a Gaussian distribution. Then, it adopts a time-inverted SDE to map a Gaussian noise gradually into a sample by multiple steps. At each sampling time step, a network is utilized to generate the sample along the gradient of the log probability, also known as the score function [50]. The iterative nature of diffusion models can result in high training and inference costs. Efficient sampling strategies [21,23,32,41,46], latent space diffusion [38,51], and multi-resolution cascaded generation [22] have been proposed to reduce the inference cost. Additionally, some training schemes [2, 12] are introduced to improve the diffusion model training, e.g., approximate maximum likelihood training [28, 34, 47], and training loss weighting [26, 27]. We identify the lack of contextual modeling ability in diffusion models. To address this, we propose the mask latent modeling scheme to enhance the contextual representation of diffusion models, which is orthogonal to existing diffusion training schemes.", + "bbox": [ + 497, + 450, + 894, + 755 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. Networks for Diffusion Models", + "text_level": 1, + "bbox": [ + 499, + 762, + 771, + 775 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The UNet-like [39] network, enhanced by spatial selfattention [42,52] and group normalization [55] is firstly used for diffusion models [21]. Several design improvements, e.g., adding more attention heads [18], BigGAN [4] residual block, and adaptive group normalization, are proposed in [11] to further enhance the generation ability of the UNet.", + "bbox": [ + 497, + 783, + 894, + 866 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "23165", + "bbox": [ + 463, + 887, + 504, + 897 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Recently, due to the broad applicability of transformer networks, several works have attempted to utilize the vision transformer (ViT) structure for diffusion models [1,35,56]. GenViT [56] demonstrates that ViT is capable of image generation but has inferior performance compared to UNet. U-ViT [1] improves ViT by adding long-skip connections and convolutional layers, achieving competitive performance with that of UNet. DiT [35] verifies the scaling ability of ViT on large model sizes and feature resolutions. Our MDT is orthogonal to these diffusion networks as it focuses on contextual representation learning. Moreover, the position-aware designs in MDT reveal that the mask latent modeling scheme benefits from a stronger diffusion network. We will explore further to release the potential of these networks with MDT.", + "bbox": [ + 75, + 125, + 472, + 332 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.3. Mask Modeling", + "text_level": 1, + "bbox": [ + 77, + 340, + 235, + 356 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Mask modeling has been proven to be effective in both recognition learning [8, 10, 15, 19] and generative modeling [7, 36]. In the natural language processing (NLP) field, mask modeling was first introduced to enable representation pretraining [10, 36] and language generation [5, 25]. Subsequently, it also proved feasible for vision recognition [3] and generation [7, 16, 57] tasks. In vision recognition, pretraining schemes that utilize mask modeling enable good representation quality [58], scalability [19] and faster convergence [15]. In generative modeling, following the bidirectional generative modeling in NLP, MaskGIT [7] and MUSE [6] use the masked generative transformer to predict randomly masked image tokens for image generation. Similarly, VQ-Diffusion [16] presents a mask-replace diffusion strategy to generate images. In contrast, our MDT aims to enhance the contextual representation of the denoising diffusion transformer [35] with mask latent modeling. This preserves the detail refinement ability of denoising diffusion models by maintaining the diffusion process during inference. To ensure that the mask latent modeling in MDT focuses on representation learning instead of reconstruction, we propose an asymmetrical structure in mask modeling training. As an extra benefit, it enables lower training costs than masked generative models because it skips the masked patches in training instead of replacing masked input patches with a mask token.", + "bbox": [ + 75, + 361, + 472, + 720 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Masked Diffusion Transformer", + "text_level": 1, + "bbox": [ + 75, + 732, + 361, + 747 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Revisit Diffusion Probabilistic Model. For diffusion probabilistic models [11, 45], such as DDPM [21] and DDIM [46], training involves a forward noising process and a reverse denoising process. In the forward noising process, Gaussian noise $\\epsilon \\sim \\mathcal{N}(0,\\mathbf{I})$ is gradually added to the real sample $x_0$ via a discrete SDE formulation [46]. If the time step $t$ is large, $x_{t}$ would be a Gaussian noise. Similarly, the reverse denoising process is a discrete SDE that grad", + "bbox": [ + 75, + 755, + 470, + 866 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/f6cbb90df5f4411a0741afb1b35c1282697025c33bd71cb9d75fbf0a09ac5078.jpg", + "image_caption": [ + "Figure 3. The overall framework of Masked Diffusion Transformer (MDT). Solid/dotted lines indicate each time step's training/inference process. Masking and side-interpolater are only used during training and are removed during inference." + ], + "image_footnote": [], + "bbox": [ + 502, + 122, + 894, + 292 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "ually maps a Gaussian noise into a sample. At each time step, given $x_{t}$ , it predicts the next reverse step $p_{\\theta}(x_{t - 1}|x_t)$ via a network. Following [34, 35], the network is trained by optimizing the variational lower-bound $L_{\\mathrm{vlb}}$ of the log-likelihood $p_{\\theta}(x_0)$ [45]. During inference, one can sample a Gaussian noise and then gradually reverses to a sample $x_0$ . Same as [34, 35], we train the diffusion model conditioned with class label $c$ , i.e. $p_{\\theta}(x_{t - 1}|x_t,c)$ . By default, we use class-conditioned image generation in our experiments.", + "bbox": [ + 497, + 366, + 894, + 492 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Overview", + "text_level": 1, + "bbox": [ + 499, + 500, + 610, + 511 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "As shown in Fig. 1, DPMs with DiT backbone exhibit slow training convergence due to the slowly learning of the associated relations among semantic parts in an image. To relieve this issue, we propose Masked Diffusion Transformer (MDT), which introduces a mask latent modeling scheme to enhance contextual learning ability explicitly. To this end, as depicted in Fig. 3, MDT consists of 1) a latent masking operation to mask the input image in the latent space, and 2) an asymmetric masking diffusion transformer structure that performs vanilla diffusion process as DPMs, but with masked input. To reduce computational costs, MDT follows LatentDiffusion [38] to perform generative learning in the latent space instead of raw pixel space.", + "bbox": [ + 497, + 520, + 890, + 700 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In the training phase, MDT first encodes an image into a latent space with a pre-trained VAE encoder [38]. Then, MDT adds Gaussian noise into the image latent embedding. The latent masking operation in MDT then patchifies the resulting noisy latent embedding into a sequence of tokens, and masks certain tokens. The remaining unmasked tokens are fed into the asymmetric masking diffusion transformer, as shown in Fig. 4(a), which contains an encoder, a side-interpolater, and a decoder to predict the masked tokens from the unmasked ones. During inference, MDT replaces the side-interpolater with additional position embedding. MDT takes the latent embedding of a Gaussian noise as input to", + "bbox": [ + 497, + 700, + 894, + 866 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "23166", + "bbox": [ + 463, + 887, + 505, + 897 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "generate the denoised latent embedding, which is then passed to a pre-trained VAE decoder [38] for image generation.", + "bbox": [ + 75, + 125, + 468, + 153 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The above masking latent modeling scheme in the training phase forces the diffusion model to reconstruct the full information of an image from its contextual incomplete input. Thus, the model is encouraged to learn the relations among image latent tokens, particularly the associated relations among semantic parts in an image. For example, as illustrated in Fig. 3, the model should first understand the correct associated relations among small image parts (tokens) of the dog image. Then, it should generate the masked \"eye\" tokens using other unmasked tokens as contextual information. Furthermore, Fig. 1 shows that MDT often learns to generate the associated semantics of an image at nearly the same pace, such as the generation of the dog's two eyes (two ears) at almost the same training step. While DiT [35] (DDPM with transformer backbone) learns to generate one eye (one ear) initially and then learns to generate another eye (ear) after roughly 100k training steps. This demonstrates the superior learning ability of MDT over DiT in terms of the associated relation learning of image semantics.", + "bbox": [ + 75, + 154, + 470, + 415 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In the following parts, we will introduce the two key components of MDT, 1) a latent masking operation, and 2) an asymmetric masking diffusion transformer structure.", + "bbox": [ + 75, + 416, + 468, + 458 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Latent Masking", + "text_level": 1, + "bbox": [ + 77, + 465, + 235, + 479 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Following the Latent diffusion model (LDM) [38], MDT performs generation learning in the latent space instead of raw pixel space to reduce computational costs. In the following, we briefly recall LDM and then introduce our latent masking operation on the latent input.", + "bbox": [ + 75, + 486, + 470, + 555 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Latent diffusion model (LDM). LDM employs a pretrained VAE encoder $\\mathbf{E}$ to encode an image $v\\in \\mathbb{R}^{3\\times H\\times W}$ to a latent embedding $z = \\mathbf{E}(v)\\in \\mathbb{R}^{c\\times h\\times w}$ . It gradually adds noise to $z$ in the forward process and then denoises to predict $z$ in the reverse process. Finally, LDM uses a pre-trained VAE decoder $\\mathbf{D}$ to decode $z$ into a high-resolution image $v = \\mathbf{D}(z)$ . Both the VAE encoder and decoder are fixed during training and inference. Since $h$ and $w$ are smaller than $H$ and $W$ , performing the diffusion process in the low-resolution latent space is more efficient than pixel space.", + "bbox": [ + 75, + 571, + 468, + 710 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Latent masking operation. We first add Gaussian noise to an image's latent embedding $z$ during training. Then following [35], we divide the noisy embedding $z$ into a sequence of $p \\times p$ -sized tokens and concatenate them to a matrix $u \\in \\mathbb{R}^{d \\times N}$ , where $d$ is the channel number and $N$ is the number of tokens. Next, we randomly mask tokens with a ratio $\\rho$ and concatenate the remaining tokens as $\\hat{u} \\in \\mathbb{R}^{d \\times \\hat{N}}$ , where $\\hat{N} = \\rho N$ . Accordingly, we can create a binary mask $M \\in \\mathbb{R}^N$ in which one (zero) denotes the masked (unmasked) tokens. Finally, we feed the tokens $\\hat{u}$", + "bbox": [ + 75, + 726, + 468, + 866 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/6e8cfbab54ad0416c1621b736a568ae60e21daec418f45fba591a96fa2584553.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 504, + 123, + 890, + 233 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/f4cb86fc985d4b48df6ca0e48d16eee101b1e0b49205d3e21e8cb54367a9b812.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 504, + 237, + 890, + 319 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/867e8bee79ceb5d3bcd61cf25a7922e807753d9aba58eaaa49a9dba627ba7462.jpg", + "image_caption": [ + "Figure 4. The asymmetric masking diffusion transformer structure in MDT. We modify the DiT [35] by adding a side-interpolater, local relative positional bias, and learnable global position embeddings. The conditional scheme is omitted for simplicity." + ], + "image_footnote": [], + "bbox": [ + 502, + 326, + 890, + 472 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "into our diffusion model for processing. We only use tokens $\\hat{u}$ for two reasons. 1) The model should focus on learning semantics instead of predicting the masked tokens. As shown in Sec. 4.3, it achieves better performance than replacing the masked tokens with a learnable mask token and then processing all tokens like [3, 6, 7]; 2) It saves the training cost compared to processing all $N$ tokens.", + "bbox": [ + 497, + 555, + 890, + 654 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Asymmetric Masking Diffusion Transformer", + "text_level": 1, + "bbox": [ + 499, + 662, + 878, + 676 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We introduce our asymmetric masking diffusion transformer for joint training of mask latent modeling and diffusion process. As shown in Fig. 4(a), it consists of three components: an encoder, a side-interpolyater, and a decoder, each of which is described in detail below.", + "bbox": [ + 497, + 682, + 892, + 751 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Position-aware encoder and decoder. In MDT, predicting the masked latent tokens from the unmasked tokens requires the position relations of all tokens. To enhance the position information in the model, we propose a positional-aware encoder and decoder that facilitate the learning of the masked latent tokens. Specifically, the encoder and decoder tailor the standard DiT block via adding two types of token position", + "bbox": [ + 497, + 769, + 890, + 866 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "23167", + "bbox": [ + 463, + 887, + 504, + 897 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "information containing $N_{1}$ and $N_{2}$ blocks, as illustrated in Fig. 4(a).", + "bbox": [ + 75, + 125, + 468, + 153 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Firstly, the encoder adds the conventional learnable global position embedding into the noisy latent embedding input. Similarly, the decoder introduces the learnable position embedding into its input but with different training and inference phase approaches. The side-interpolater already uses the learnable global position embedding introduced below during training. During inference, since the side interpolater is discarded (see below), the decoder explicitly adds the position embedding into its input to enhance positional information.", + "bbox": [ + 75, + 153, + 470, + 290 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Secondly, as depicted in Fig. 4(b), the encoder and decoder add a local relative positional bias [30] to each head in each block when computing the attention score of the self-attention [53]:", + "bbox": [ + 75, + 290, + 470, + 347 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {A t t e n t i o n} (Q, K, V) = \\operatorname {S o f t m a x} \\left(\\frac {Q K ^ {\\top}}{\\sqrt {d _ {k}}} + B _ {r}\\right) V,\n$$\n", + "text_format": "latex", + "bbox": [ + 102, + 353, + 442, + 385 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $Q$ , $K$ , and $V$ , respectively denote the query, key, and value in the self-attention module, $d_k$ is the dimension of the key, and $B_r \\in \\mathbb{R}^{N \\times N}$ is the relative positional bias. $B_r$ is selected by the relative positional difference between the $i$ -th position and other positions, which is updated during training. The local relative positional bias helps to capture the relative relations among tokens, facilitating the masking of latent modeling.", + "bbox": [ + 75, + 391, + 468, + 502 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The encoder takes the unmasked noisy latent embedding provided by our latent masking operation and feeds its output into the side-interpolater/decoder during training/inference. For the decoder, its input is the output of the side-interpolater for training or the combination of the encoder output and the learnable position embedding for inference. During training, the encoder and decoder, respectively, handle unmasked tokens and full tokens. Thus, we name our model the \"asymmetric\" model.", + "bbox": [ + 75, + 503, + 470, + 625 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Side-interpolater. As shown in Fig. 3, during training, for efficiency and better performance, the encoder only processes the unmasked tokens $\\hat{u}$ . While in the inference phase, the encoder handles all tokens $u$ due to the lack of masks. This means that there is a big difference in the encoder output (i.e., decoder input) during training and inference, at least in terms of token number. To ensure the decoder always processes all tokens for training prediction or inference generation, a side-interpolyter implemented by a small network aims to predict masked tokens from encoder output during training and would be removed during inference.", + "bbox": [ + 75, + 643, + 468, + 795 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In the training phase, the encoder processes the unmasked tokens to obtain its output token embedding $\\hat{q} \\in \\mathbb{R}^{d \\times \\hat{N}}$ . Then, as shown in Fig. 4(c), the side-interpolater first fills the masked positions, indicated by the mask $M$ defined in Sec. 3.2, by a shared learnable mask token, and also adds", + "bbox": [ + 75, + 795, + 468, + 866 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "a learnable positional embedding to obtain an embedding $q \\in \\mathbb{R}^{d \\times N}$ . Next, we use a basic encoder block to process $q$ to predict an interpolated embedding $\\hat{k}$ . The $\\hat{k}$ tokens denote the predicted tokens. Finally, we use a masked shortcut connection to combine prediction $\\hat{k}$ and $q$ as $k = M \\cdot q + (1 - M) \\cdot \\hat{k}$ . In summary, for masked tokens, we use the prediction by side-interpolyter. For unmasked tokens, we still adopt the corresponding tokens in $q$ . This can 1) boost the consistency between training and inference phases, 2) eliminates the mask-reconstruction process in the decoder.", + "bbox": [ + 497, + 125, + 892, + 264 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Since there are no masks during inference, the side-interpolater is replaced by a position embedding operation, which adds the learnable position embeddings of the side-interpolater, learned during training. This ensures the decoder always processes all tokens and uses the same learnable position embeddings for training prediction or inference generation, thus having better image generation performance.", + "bbox": [ + 497, + 264, + 894, + 374 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.4. Training", + "text_level": 1, + "bbox": [ + 499, + 382, + 603, + 397 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "During training, we feed both full latent embedding $u$ and the masked latent embedding $\\hat{u}$ to the diffusion model. We observe that only using masked latent embedding makes the model focus too much on masked region reconstruction, while ignoring the diffusion training. Full/masked latent inputs are independently sent to the network, and the training objectives optimize the variational lower-bound, as in [34, 35]. Due to the asymmetrical masking structure, the extra costs for using masked latent embedding are small. This is also demonstrated by Fig. 1, which shows that MDT still achieves about $3 \\times$ faster learning progress than previous SOTA DiT in total training hours.", + "bbox": [ + 497, + 403, + 894, + 568 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 499, + 581, + 631, + 596 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Implementation", + "text_level": 1, + "bbox": [ + 499, + 603, + 658, + 618 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We give the implementation details of MDT, including model architecture, training details, and evaluation metrics.", + "bbox": [ + 499, + 624, + 890, + 653 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Model architecture. We follow DiT [35] to set the total block number (i.e., $N_{1} + N_{2}$ ), token number, and channel numbers of the diffusion transformer of MDT. As DiT reveals stronger synthesis performance when using a smaller patch size, we also use a patch size $p = 2$ by default, denoted by MDT-/2. Moreover, We also follow DiT's parameters to design MDT for getting its small-, base-, and xlarge-sized model, denoted by MDT-S/B/XL. Same as LatentDiffusion [38] and DiT, MDT adopts the fixed $\\mathrm{VAE}^{1}$ provided by the Stable Diffusion to encode/decode the image/latent tokens by default. The VAE encoder has a downsampling ratio of $1 / 8$ , and a feature channel dimension of 4, e.g., an image", + "bbox": [ + 497, + 668, + 894, + 836 + ], + "page_idx": 4 + }, + { + "type": "page_footnote", + "text": "1The model is downloaded in https://huggingface.co/stabilityai/sd-vae-ft-mse", + "bbox": [ + 499, + 842, + 892, + 866 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "23168", + "bbox": [ + 463, + 887, + 505, + 897 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/f1593e333238d28ac71a06e0dce3f601b9290826b29a930c590166ac23491d35.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodImage Res.Training Steps (k)FID-50K↓
DiT-S/2256×25640068.40
MDT-S/2256×25630057.01
MDT-S/2256×25640053.46
MDT-S/2256×256200044.14
MDT-S/2256×256350041.37
DiT-B/2256×25640043.47
MDT-B/2256×25640034.33
MDT-B/2256×256350020.45
DiT-XL/2256×25640019.47
DiT-XL/2256×256235210.67
DiT-XL/2256×25670009.62
MDT-XL/2256×25640016.42
MDT-XL/2256×25613009.60
MDT-XL/2256×25635006.65
", + "bbox": [ + 78, + 123, + 467, + 342 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "of size $256 \\times 256 \\times 3$ is encoded into a latent embedding of size $32 \\times 32 \\times 4$ .", + "bbox": [ + 75, + 409, + 468, + 437 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Training details. Following [35], all models are trained by AdamW [31] optimizer of 3e-4 learning rate, 256 batch size, and without weight decay on ImageNet [9] with an image resolution of $256 \\times 256$ . We set the mask ratio as 0.3 and $N_{2} = 2$ . Following the training settings in DiT, we set the maximum step in training to 1000 and use the linear variance schedule with a range from $10^{-4}$ to $2 \\times 10^{-2}$ . Other settings are also aligned with DiT.", + "bbox": [ + 75, + 456, + 468, + 568 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Evaluation. We evaluate models with commonly used metrics, i.e. Frechet Inception Distance (FID) [20], sFID [33], Inception Score (IS) [40], Precision and Recall [29]. The FID is used as the major metric as it measures both diversity and fidelity. sFID improves upon FID by evaluating at the spatial level. As a complement, IS and Precision are used for measuring fidelity, and Recall is used to measure diversity. For fair comparisons, we follow [35] to use the TensorFlow evaluation suite from ADM [11] and report FID-50K with 250 DDPM sampling steps. Unless specified otherwise, we report the FID scores without the classifier-free guidance [23].", + "bbox": [ + 75, + 586, + 470, + 751 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Comparison Results", + "text_level": 1, + "bbox": [ + 75, + 761, + 268, + 776 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Performance comparison. Tab. 1 compares our MDT with the SOTA DiT under different model sizes. It is evident that MDT achieves higher FID scores for all model scales with fewer training costs. The parameters and inference cost of MDTs are similar to DiT, since the extra modules in MDT are negligible as introduced in Sec. 3.1. For small models,", + "bbox": [ + 75, + 783, + 468, + 866 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/3dac5958423c398819d1ced05c116ca7e636a5840228b619cab6261fc8475e6b.jpg", + "table_caption": [ + "Table 1. Comparison between DiT [35] and MDT under different model sizes and training steps on ImageNet $256\\times 256$ . DiT results are obtained from DiT reported results." + ], + "table_footnote": [], + "table_body": "
MethodCost(ITer×BS)FID↓sFID↓IS↑Prec.↑Rec.↑
DCTrans. [33]-36.51--0.360.67
VQVAE-2 [37]-31.11--0.360.57
VQGAN [13]-15.7878.3---
BigGAN-deep [4]-6.957.36171.40.870.28
StyleGAN [43]-2.304.02265.120.780.53
Impr. DDPM [34]-12.26--0.700.62
MaskGIT [7]1387k×2566.18-182.10.800.51
CDM [22]-4.88-158.71--
ADM [11]1980k×25610.946.02100.980.690.63
LDM-8 [38]4800k×6415.51-79.030.650.63
LDM-4178k×120010.56-103.490.710.62
DiT-XL/2 [35]7000k×2569.626.85121.500.670.67
MDT2500k×2567.414.95121.220.720.64
MDT3500k×2566.464.92131.700.720.63
MDT6500k×2566.235.23143.020.710.65
ADM-G [11]1980k×2564.595.25186.700.820.52
ADM-G, U1980k×2563.946.14215.840.830.53
LDM-8-G [38]4800k×647.76-209.520.840.35
LDM-4-G178k×12003.60-247.670.870.48
U-ViT-G [1]300k×10243.40----
DiT-XL/2-G [35]7000k×2562.274.60278.240.830.57
MDT-G2500k×2562.154.52249.270.820.58
MDT-G3500k×2562.024.46263.770.820.60
MDT-G6500k×2561.794.57283.010.810.61
", + "bbox": [ + 500, + 124, + 890, + 467 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2. Comparison with existing methods on class-conditional image generation with the ImageNet $256 \\times 256$ dataset. -G denotes the results with classifier-free guidance [23]. Results of MDT-XL/2 model are given for comparison. Compared results are obtained from their papers.", + "bbox": [ + 497, + 479, + 890, + 543 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "MDT-S/2 trained with 300k steps outperforms the DiT-S/2 trained with 400k steps by a large margin on FID (57.01 vs. 68.40). More importantly, MDT-S/2 trained with 2000k steps achieves similar performance with a larger model DiT-B/2 trained with a similar computational budget. For the largest model, MDT-XL/2 trained with 1300k steps outperforms DiT-XL/2 trained with 7000k steps on FID (9.60 vs. 9.62), achieving about $5 \\times$ faster training progress.", + "bbox": [ + 497, + 572, + 892, + 684 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We also compare the class-conditional image generation performance of MDT with existing methods in Tab. 2. To make fair comparisons with DiT, we also use the EMA weights of VAE decoder in this table. Under class-conditional settings, MDT with half training iterations outperforms DiT by a large margin, e.g., 6.83 vs 9.62 in FID. Following previous works [1, 11, 35, 38], we utilize an improved classifier-free guidance [23] with a power-cosine weight scaling to trade off between precision and recall during class-conditional sampling. MDT achieves superior performance over previous SOTA DiT and other methods with the FID score of 1.81, setting a new SOTA for class-conditional image generation. Similar to DiT, we never", + "bbox": [ + 497, + 687, + 894, + 866 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "23169", + "bbox": [ + 463, + 887, + 504, + 897 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/0475b28be2b06848cf2b82f3e93a41b6301b0cb257a521482f548fc2ae776fff.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Mask RatioFID↓sFID↓IS↑Precision↑Recall↑
0.151.6010.2326.650.440.60
0.251.4410.0926.750.440.58
0.350.2610.0827.610.450.60
0.450.8810.2127.440.450.60
0.551.579.9227.140.440.60
0.653.2010.3626.550.440.61
0.752.9010.0326.510.440.61
0.853.7310.1525.550.430.61
", + "bbox": [ + 80, + 123, + 460, + 252 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/2d85541f4505e3ee89b1a071d363ef2284aab467c37a2fee417e004fd1cc35d5.jpg", + "table_caption": [ + "Table 3. Effect of different masking ratios. MDT-S/2 trained with 600k iterations." + ], + "table_footnote": [], + "table_body": "
Decoder pos.FID↓sFID↓IS↑Precision↑Recall↑
Last051.059.9727.310.440.60
Last150.969.9027.630.450.60
Last250.2610.0827.610.450.60
Last451.6710.1226.910.450.60
Last652.6410.3626.460.440.60
", + "bbox": [ + 80, + 294, + 460, + 385 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 4. Effect of position of side-interpolater. MDT-S/2 models contain 12 blocks and are trained with 600k iterations.", + "bbox": [ + 77, + 391, + 467, + 416 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "observe the model has saturated FID scores when continuing training.", + "bbox": [ + 77, + 439, + 467, + 466 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Convergence speed. Fig. 1 compares the performance of the DiT/S-2 baseline and MDT/S-2 under different training steps and training time on $8 \\times \\mathrm{A}100$ GPUs. Because of the stronger contextual learning ability, MDT achieves better performance with faster generation learning speed. MDT enjoys about $3 \\times$ faster learning speed in terms of both training steps and training time. For example, MDT-S/2 trained with about 33 hours (400k steps) achieves superior performance than DiT-S/2 trained with about 100 hours (1500k steps). This reveals that contextual learning is vital for faster generation learning of diffusion models.", + "bbox": [ + 75, + 485, + 468, + 636 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Ablation", + "text_level": 1, + "bbox": [ + 77, + 646, + 181, + 659 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In this part, we conduct ablation to verify the designs in MDT. We report the results of MDT-S/2 model and use FID-50k as the evaluation metric unless otherwise stated.", + "bbox": [ + 77, + 668, + 467, + 707 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Masking ratio. The masking ratio determines the number of input patches that can be processed during training. We give the comparison of using different masking ratios in Tab. 3. The best masking ratio for MDT-S/2 is $30\\%$ , which is quite different from the masking ratio used for recognition models, e.g. $75\\%$ masking ratio in MAE [19]. We assume that the image generation requires learning more details from more patches for high-quality synthesis, while recognition models only need the most essential patches to infer semantics.", + "bbox": [ + 75, + 726, + 468, + 865 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Side-interpolater position. To meet the high-quality image generation requirements of the diffusion model, the side-interpolater is placed in the middle of the network instead of the end of the network in recognition models [3, 19]. Tab. 4, presents the comparison of placing the side-interpolater at different positions of the MDT-S model with 12 blocks. The results show that placing the side-interpolater before the last two blocks achieves the best FID score, whereas placing it at the end of the network like recognition models impairs the performance. Placing the side-interpolater at the early stages of the network also harm the performance, indicating the mask latent modeling is beneficial to most stages in the diffusion models.", + "bbox": [ + 499, + 125, + 890, + 304 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Asymmetric vs. Symmetric architecture in masking. Unlike the masked generation works [6, 7], e.g., MaskGIT, that utilize the masking scheme to generate images, MDT focuses on improving diffusion models with contextual learning ability via the masking latent modeling. Therefore, we use an asymmetric architecture to only process the unmasked tokens in the diffusion model encoder. We compare the asymmetric architecture in MDT and the symmetrical architecture [7] that processes full input with masked tokens replaced by a learnable mask token. As shown in Tab. 5a, the asymmetric architecture in MDT has an FID of 50.26, outperforming the FID of 51.56 achieved by the symmetric architecture. The asymmetric architecture further reduces the training cost and allows the diffusion model to focus on learning contextual information instead of reconstructing masked tokens.", + "bbox": [ + 499, + 324, + 892, + 543 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Effect of side-interpolater. The side-interpolater in MDT predicts the masked tokens, allowing the diffusion model to learn more semantics and maintain consistency in decoder inputs during training and inference. We compare the performance with/without the side-interpolater in Tab. 5b, and observe a gain of 1.34 in FID when using the side-interpolater, proving its effectiveness.", + "bbox": [ + 499, + 564, + 890, + 661 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Masked shortcut in side-interpolater. The masked shortcut ensures that the side-interpolater only predicts the masked tokens from unmasked ones. Tab. 5c shows that using the masked shortcut enhances the FID from 50.91 to 50.26, indicating that restricting side-interpolater to only predict masked tokens helps the diffusion model achieve stronger performance.", + "bbox": [ + 499, + 681, + 890, + 777 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Full and masked latent tokens. In MDT, both the full and masked latent embeddings are fed into the diffusion model during training. In comparison, we give the results trained by only using full/masked latent embeddings as shown in Tab. 5d, where the computational cost is aligned for", + "bbox": [ + 499, + 796, + 890, + 866 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "23170", + "bbox": [ + 463, + 887, + 504, + 897 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/79fe9cfa5887795e4b6d47f67abee62e944bd774666e53caeb19c98b4d3defb0.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Asymmetric stru.FID-50k↓
×51.56
✓50.26
", + "bbox": [ + 90, + 134, + 349, + 188 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/6de7d39a42b4a0b7e05db4524f2c0b14242db0caf917cd1f570134653385ad57.jpg", + "table_caption": [ + "(a) Effect of asymmetric masking structure." + ], + "table_footnote": [], + "table_body": "
Side-interpolaterFID-50k↓
×51.60
✓50.26
", + "bbox": [ + 354, + 134, + 616, + 188 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/e6e8acfd866911f0cd7016f68d8658c0a8e531e62e969fdb93d07440dafe71e2.jpg", + "table_caption": [ + "(b) Effect of side-interpolater." + ], + "table_footnote": [], + "table_body": "
Masked shortcutFID-50k↓
×50.91
✓50.26
", + "bbox": [ + 621, + 134, + 882, + 188 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/4889b9365d617c81a47424df6cf2518342650dd355531287726f354852ed8916.jpg", + "table_caption": [ + "(c) Effect of masked shortcut." + ], + "table_footnote": [], + "table_body": "
Latent typeFID-50k↓
Full+Masked50.26
Full52.30
Masked76.63
", + "bbox": [ + 90, + 214, + 344, + 279 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/5f2c0f0357cf74171612d98877129425ec4fdad33ff0ce72c3c7854d4f0afd7a.jpg", + "table_caption": [ + "(d) Using full/masked latent under aligned cost." + ], + "table_footnote": [], + "table_body": "
Sup. partsFID-50k↓
All50.26
Masked58.35
", + "bbox": [ + 354, + 214, + 615, + 279 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/7440d3cbc06bb9f0cfadeb858fa1eedd6165ef4a7044779e52be8096afeb6f32.jpg", + "table_caption": [ + "(e) Supervision on token parts." + ], + "table_footnote": [], + "table_body": "
NumberFID-50k↓
150.26
251.77
351.96
", + "bbox": [ + 621, + 214, + 882, + 279 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/0c025f94c2129809bc3228355aa4e7033491e4c88dd20ddb3841b603c32af2d9.jpg", + "table_caption": [ + "(f) Number of blocks in side-interpolator." + ], + "table_footnote": [], + "table_body": "
IS Pos. embed.FID-50k↓
×51.58
✓50.26
", + "bbox": [ + 90, + 305, + 347, + 358 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/8683b7992fc4a6dfa68bdddb19cd2c8dcd06ae418c6ddadf73d73c9dc85d1e20.jpg", + "table_caption": [ + "(g) Effect of positional embeddings in SI." + ], + "table_footnote": [], + "table_body": "
Learnable pos.FID-50k↓
×50.80
✓50.26
", + "bbox": [ + 354, + 305, + 613, + 358 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/90190e2b64420a83b5f922c0fbba435311894e80ba63b3de1ccf80ee81a17471.jpg", + "table_caption": [ + "(h) Effect of learnable positional embeddings." + ], + "table_footnote": [], + "table_body": "
Relative pos. biasFID-50k↓
×53.56
✓50.26
", + "bbox": [ + 621, + 305, + 882, + 358 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "(i) Effect of relative positional bias.", + "bbox": [ + 655, + 361, + 843, + 372 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 5. Ablation study on MDT-S/2. Models are trained for 600k iterations.", + "bbox": [ + 257, + 376, + 709, + 388 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "fair comparisons. Trained with both full and masked latent leads to clear gain over two competitors. While using only the masked latent embeddings results in slow convergence, which we attribute to the training/inference inconsistency as the inference in MDT is a diffusion process instead of the masked reconstruction process.", + "bbox": [ + 75, + 412, + 468, + 495 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Loss on all tokens. By default, we calculate the loss on both masked and unmasked latent embeddings. In comparison, mask modeling for recognition models commonly calculates loss on masked tokens [3, 19]. Tab. 5e shows that calculating the loss on all tokens is much better than on masked tokens. We assume that this is because generative models require stronger consistency among patches than recognition models do, since details are vital for high-quality image synthesis.", + "bbox": [ + 75, + 511, + 468, + 637 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Block number in side-interpolater. We compare the performance of different numbers of blocks in the side-interpolater in Tab. 5f. The default setting of 1 block achieves the best performance, and the FID worsens with an increase in block number. This result is consistent with our motivation that side-interpolater should not learn too much information other than interpolating the masked representations.", + "bbox": [ + 75, + 654, + 468, + 751 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Positional-aware enhancement. To further release the potential of mask latent modeling, we enhance the DiT baseline with stronger positional awareness ability, i.e. learnable positional embeddings and the relative positional bias in basic blocks. Tab. 5g shows the positional embeddings in side-interpolator improves the FID from 51.58 to 50.26, indicating the positional embedding is vital for the side-interpolator.", + "bbox": [ + 75, + 769, + 470, + 866 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Also, enables the training of positional embeddings brings the gain in FID as revealed in Tab. 5h. In Tab. 5i, the relative positional bias in the basic blocks significantly improves the FID from 53.56 to 50.26, showing the relative positional modeling ability is essential for diffusion models to obtain the contextual representation ability and generate high-quality images. Therefore, the positional awareness ability in diffusion model structure is required to accompany the masked latent modeling, playing a key role in improving performance.", + "bbox": [ + 497, + 412, + 892, + 551 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 499, + 560, + 618, + 574 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "This work proposes a masked diffusion transformer to enhance the contextual representation and improve the relation learning among image semantics for DPMs. We introduce an effective mask latent modeling scheme into DPMs and also accordingly designs an asymmetric masking diffusion transformer structure. Experiments show that our masked diffusion transformer enjoys higher performance on image synthesis and largely improves the learning progress during training, achieving the new SOTA for image synthesis on the ImageNet dataset. We hope our initial exploration of contextual learning for generative modeling can facilitate more work on unifying the representation learning for recognition and generative models.", + "bbox": [ + 497, + 584, + 892, + 763 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgement.", + "text_level": 1, + "bbox": [ + 499, + 774, + 663, + 789 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "This research was supported by the NSFC (NO. 62225604) and the Fundamental Research Funds for the Central Universities (Nankai University, 070-63233089). The Supercomputing Center of Nankai University supports computation.", + "bbox": [ + 497, + 796, + 892, + 866 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "23171", + "bbox": [ + 463, + 887, + 502, + 897 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 124, + 171, + 138 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Fan Bao, Chongxuan Li, Yue Cao, and Jun Zhu. All are worth words: a vit backbone for score-based diffusion models. arXiv preprint arXiv:2209.12152, 2022. 3, 6", + "[2] Fan Bao, Chongxuan Li, Jiacheng Sun, Jun Zhu, and Bo Zhang. Estimating the optimal covariance with imperfect mean in diffusion probabilistic models. In Int. Mach. Learn., 2022. 2", + "[3] Hangbo Bao, Li Dong, and Furu Wei. Beit: Bert pre-training of image transformers. Int. Conf. Learn. Represent., 2022. 3, 4, 7, 8", + "[4] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. Int. Conf. Learn. Represent., 2019. 1, 2, 6", + "[5] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, et al. Language models are few-shot learners. Adv. Neural Inform. Process. Syst., 33:1877-1901, 2020. 3", + "[6] Huiwen Chang, Han Zhang, Jarred Barber, AJ Maschinot, Jose Lezama, Lu Jiang, Ming-Hsuan Yang, Kevin Murphy, William T Freeman, Michael Rubinstein, et al. Muse: Text-to-image generation via masked generative transformers. arXiv preprint arXiv:2301.00704, 2023. 3, 4, 7", + "[7] Huiwen Chang, Han Zhang, Lu Jiang, Ce Liu, and William T Freeman. Maskgit: Masked generative image transformer. In IEEE Conf. Comput. Vis. Pattern Recog., pages 11315-11325, 2022. 3, 4, 6, 7", + "[8] Gong Cheng, Ruimin Li, Chunbo Lang, and Junwei Han. Task-wise attention guided part complementary learning for few-shot image classification. Science China Information Sciences, 64:1-14, 2021. 3", + "[9] J. Deng, W. Dong, R. Socher, L.-J. Li, K. Li, and L. Fei-Fei. Imagenet: A large-scale hierarchical image database. In IEEE Conf. Comput. Vis. Pattern Recog., 2009. 1, 6", + "[10] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. NAACL, 2019. 3", + "[11] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Adv. Neural Inform. Process. Syst., 34:8780-8794, 2021. 1, 2, 3, 6", + "[12] Tim Dockhorn, Arash Vahdat, and Karsten Kreis. Score-based generative modeling with critically-damped Langevin diffusion. In Int. Conf. Learn. Represent., 2022. 2", + "[13] Patrick Esser, Robin Rombach, and Bjorn Ommer. Taming transformers for high-resolution image synthesis. In IEEE Conf. Comput. Vis. Pattern Recog., pages 12873-12883, 2021. 6", + "[14] Shanghua Gao, Zhong-Yu Li, Ming-Hsuan Yang, Ming-Ming Cheng, Junwei Han, and Philip Torr. Large-scale unsupervised semantic segmentation. IEEE Trans. Pattern Anal. Mach. Intell., 2022. 1", + "[15] Shanghua Gao, Pan Zhou, Ming-Ming Cheng, and Shuicheng Yan. Towards sustainable self-supervised learning. arXiv preprint arXiv:2210.11016, 2022. 3" + ], + "bbox": [ + 78, + 148, + 470, + 866 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[16] Shuyang Gu, Dong Chen, Jianmin Bao, Fang Wen, Bo Zhang, Dongdong Chen, Lu Yuan, and Baining Guo. Vector quantized diffusion model for text-to-image synthesis. In IEEE Conf. Comput. Vis. Pattern Recog., pages 10696-10706, 2022. 3", + "[17] Yuchao Gu, Xintao Wang, Yixiao Ge, Ying Shan, Xiaohu Qie, and Mike Zheng Shou. Rethinking the objectives of vector-quantized tokenizers for image synthesis. arXiv preprint arXiv:2212.03185, 2022. 1", + "[18] Meng-Hao Guo, Tian-Xing Xu, Jiang-Jiang Liu, Zheng-Ning Liu, Peng-Tao Jiang, Tai-Jiang Mu, Song-Hai Zhang, Ralph R. Martin, Ming-Ming Cheng, and Shi-Min Hu. Attention mechanisms in computer vision: A survey. Computational Visual Media, 8(3):331-368, 2022. 2", + "[19] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollar, and Ross Girshick. Masked autoencoders are scalable vision learners. In IEEE Conf. Comput. Vis. Pattern Recog., pages 16000-16009, 2022. 3, 7, 8", + "[20] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Adv. Neural Inform. Process. Syst., 30, 2017. 6", + "[21] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Adv. Neural Inform. Process. Syst., 33:6840-6851, 2020. 1, 2, 3", + "[22] Jonathan Ho, Chitwan Sahara, William Chan, David J Fleet, Mohammad Norouzi, and Tim Salimans. Cascaded diffusion models for high fidelity image generation. J. Mach. Learn. Res., 23(47):1-33, 2022. 2, 6", + "[23] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. NeurIPS Workshop, 2021. 2, 6", + "[24] Myeonghun Jeong, Hyeongju Kim, Sung Jun Cheon, Byoung Jin Choi, and Nam Soo Kim. Diff-tps: A denoising diffusion model for text-to-speech. In INTERSPEECH, 2021. 1", + "[25] Ge-Peng Ji, Mingchen Zhuge, Dehong Gao, Deng-Ping Fan, Christos Sakaridis, and Luc Van Gool. Masked vision-language transformer in fashion. Machine Intelligence Research, 20(3):421-434, 2023. 3", + "[26] Tero Karras, Miika Aittala, Timo Aila, and Samuli Laine. Elucidating the design space of diffusion-based generative models. In Adv. Neural Inform. Process. Syst., 2022. 2", + "[27] Dongjun Kim, Seungjae Shin, Kyungwoo Song, Wanmo Kang, and Il-Chul Moon. Soft truncation: A universal training technique of score-based diffusion model for high precision score estimation. In Int. Mach. Learn., 2022. 2", + "[28] Diederik Kingma, Tim Salimans, Ben Poole, and Jonathan Ho. Variational diffusion models. Adv. Neural Inform. Process. Syst., 34:21696-21707, 2021. 2", + "[29] Tuomas Kynkänniemi, Tero Karras, Samuli Laine, Jaakko Lehtinen, and Timo Aila. Improved precision and recall metric for assessing generative models. Adv. Neural Inform. Process. Syst., 32, 2019. 6", + "[30] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Int. Conf. Comput. Vis., pages 10012-10022, 2021. 5" + ], + "bbox": [ + 502, + 125, + 892, + 866 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "23172", + "bbox": [ + 463, + 887, + 504, + 897 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[31] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. Int. Conf. Learn. Represent., 2019. 6", + "[32] Cheng Lu, Yuhao Zhou, Fan Bao, Jianfei Chen, Chongxuan Li, and Jun Zhu. Dpm-solver: A fast ode solver for diffusion probabilistic model sampling in around 10 steps. Adv. Neural Inform. Process. Syst., 2022. 1, 2", + "[33] Charlie Nash, Jacob Menick, Sander Dieleman, and Peter W Battaglia. Generating images with sparse representations. Int. Mach. Learn., 2021. 6", + "[34] Alexander Quinn Nichol and Prafulla Dhariwal. Improved denoising diffusion probabilistic models. In Int. Mach. Learn., pages 8162-8171. PMLR, 2021. 2, 3, 5, 6", + "[35] William Peebles and Saining Xie. Scalable diffusion models with transformers. arXiv preprint arXiv:2212.09748, 2022. 1, 2, 3, 4, 5, 6", + "[36] Alec Radford, Karthik Narasimhan, Tim Salimans, Ilya Sutskever, et al. Improving language understanding by generative pre-training, 2018. 3", + "[37] Ali Razavi, Aaron Van den Oord, and Oriol Vinyals. Generating diverse high-fidelity images with vq-vae-2. Adv. Neural Inform. Process. Syst., 32, 2019. 1, 6", + "[38] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In IEEE Conf. Comput. Vis. Pattern Recog., pages 10684-10695, 2022. 1, 2, 3, 4, 5, 6", + "[39] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In Int. Conf. Med Image Comput Comput Assist Interv., pages 234-241. Springer, 2015. 2", + "[40] Tim Salimans, Ian Goodfellow, Wojciech Zaremba, Vicki Cheung, Alec Radford, and Xi Chen. Improved techniques for training gans. Adv. Neural Inform. Process. Syst., 29, 2016. 6", + "[41] Tim Salimans and Jonathan Ho. Progressive distillation for fast sampling of diffusion models. Int. Conf. Learn. Represent., 2022. 1, 2", + "[42] Tim Salimans, Andrej Karpathy, Xi Chen, and Diederik P Kingma. PixelCNN++: Improving the pixelCNN with discretized logistic mixture likelihood and other modifications. In Int. Conf. Learn. Represent., 2017. 2", + "[43] Axel Sauer, Katja Schwarz, and Andreas Geiger. Stylegan-xl: Scaling stylegan to large diverse datasets. In ACM SIGGRAPH 2022 conference proceedings, pages 1-10, 2022. 6", + "[44] Christoph Schuhmann, Romain Beaumont, Richard Vencu, Cade Gordon, Ross Wightman, Mehdi Cherti, Theo Coombes, Aarush Katta, Clayton Mullis, Mitchell Wortsman, et al. Laion-5b: An open large-scale dataset for training next generation image-text models. Adv. Neural Inform. Process. Syst., 2022. 1", + "[45] Jascha Sohl-Dickstein, Eric Weiss, Niru Maheswaranathan, and Surya Ganguli. Deep unsupervised learning using nonequilibrium thermodynamics. In Int. Mach. Learn., pages 2256-2265. PMLR, 2015. 3", + "[46] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. In Int. Conf. Learn. Represent., 2021. 2, 3" + ], + "bbox": [ + 78, + 125, + 470, + 865 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[47] Yang Song, Conor Durkan, Iain Murray, and Stefano Ermon. Maximum likelihood training of score-based diffusion models. Adv. Neural Inform. Process. Syst., 34:1415-1428, 2021. 2", + "[48] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. Adv. Neural Inform. Process. Syst., 32, 2019. 2", + "[49] Yang Song and Stefano Ermon. Improved techniques for training score-based generative models. Adv. Neural Inform. Process. Syst., 33:12438-12448, 2020. 2", + "[50] Yang Song, Jascha Sohl-Dickstein, Diederik P Kingma, Abhishek Kumar, Stefano Ermon, and Ben Poole. Score-based generative modeling through stochastic differential equations. Int. Conf. Learn. Represent., 2021. 2", + "[51] Arash Vahdat, Karsten Kreis, and Jan Kautz. Score-based generative modeling in latent space. In Adv. Neural Inform. Process. Syst., 2021. 2", + "[52] Aaron Van den Oord, Nal Kalchbrenner, Lasse Espeholt, Oriol Vinyals, Alex Graves, et al. Conditional image generation with pixelCNN decoders. Adv. Neural Inform. Process. Syst., 29, 2016. 2", + "[53] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Adv. Neural Inform. Process. Syst., 30, 2017. 5", + "[54] Yan Wu, Jeff Donahue, David Balduzzi, Karen Simonyan, and Timothy Lillicrap. Logan: Latent optimisation for generative adversarial networks. Int. Conf. Learn. Represent., 2020. 1", + "[55] Yuxin Wu and Kaiming He. Group normalization. In Eur. Conf. Comput. Vis., pages 3-19, 2018. 2", + "[56] Xiulong Yang, Sheng-Min Shih, Yinlin Fu, Xiaoting Zhao, and Shihao Ji. Your vit is secretly a hybrid discriminative-generative diffusion model. arXiv preprint arXiv:2208.07791, 2022.3", + "[57] Zhu Zhang, Jianxin Ma, Chang Zhou, Rui Men, Zhikang Li, Ming Ding, Jie Tang, Jingren Zhou, and Hongxia Yang. M6-ufc: Unifying multi-modal controls for conditional image synthesis. Adv. Neural Inform. Process. Syst., 2021. 3", + "[58] Jinghao Zhou, Chen Wei, Huiyu Wang, Wei Shen, Cihang Xie, Alan Yuille, and Tao Kong. ibot: Image bert pre-training with online tokenizer. Int. Conf. Learn. Represent., 2022. 3" + ], + "bbox": [ + 502, + 125, + 892, + 646 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "23173", + "bbox": [ + 463, + 887, + 504, + 897 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/a412e570-59ba-43e9-aea5-2909edb799b1_model.json b/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/a412e570-59ba-43e9-aea5-2909edb799b1_model.json new file mode 100644 index 0000000000000000000000000000000000000000..ecffc161188460337077dfe907af8f26087602cf --- /dev/null +++ b/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/a412e570-59ba-43e9-aea5-2909edb799b1_model.json @@ -0,0 +1,2222 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.13, + 0.051, + 0.201, + 0.086 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.254, + 0.049, + 0.79, + 0.087 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.176, + 0.162, + 0.795, + 0.182 + ], + "angle": 0, + "content": "Masked Diffusion Transformer is a Strong Image Synthesizer" + }, + { + "type": "text", + "bbox": [ + 0.186, + 0.207, + 0.782, + 0.241 + ], + "angle": 0, + "content": "Shanghua Gao\\(^{1,2}\\) * Pan Zhou\\(^{2\\dagger}\\) Ming-Ming Cheng\\(^{1\\dagger}\\) Shuicheng Yan\\(^{2}\\) \n\\(^{1}\\)Nankai University Sea AI Lab" + }, + { + "type": "text", + "bbox": [ + 0.172, + 0.243, + 0.798, + 0.257 + ], + "angle": 0, + "content": "{shanghuagao, shuicheng.yan} \\(@\\) gmail.com zhoupan@sea.com cmm@nankai.edu.cn" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.289, + 0.314, + 0.303 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.318, + 0.474, + 0.594 + ], + "angle": 0, + "content": "Despite its success in image synthesis, we observe that diffusion probabilistic models (DPMs) often lack contextual reasoning ability to learn the relations among object parts in an image, leading to a slow learning process. To solve this issue, we propose a Masked Diffusion Transformer (MDT) that introduces a mask latent modeling scheme to explicitly enhance the DPMs' ability to contextual relation learning among object semantic parts in an image. During training, MDT operates in the latent space to mask certain tokens. Then, an asymmetric masking diffusion transformer is designed to predict masked tokens from unmasked ones while maintaining the diffusion generation process. Our MDT can reconstruct the full information of an image from its incomplete contextual input, thus enabling it to learn the associated relations among image tokens. Experimental results show that MDT achieves superior image synthesis performance, e.g., a new SOTA FID score in the ImageNet data set, and has about \\(3 \\times\\) faster learning speed than the previous SOTA DiT. The source code is released at https://github.com/sail-sg/MDT." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.619, + 0.21, + 0.633 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.642, + 0.472, + 0.837 + ], + "angle": 0, + "content": "Diffusion probabilistic models (DPMs) [11, 38] have been at the forefront of recent advances in image-level generative models, often surpassing the previously state-of-the-art (SOTA) generative adversarial networks (GANs) [4, 17, 37, 54]. Additionally, DPMs have demonstrated their success in numerous other applications, including text-to-image generation [38] and speech generation [24]. DPMs adopt a time-inverted Stochastic Differential Equation (SDE) to gradually map a Gaussian noise into a sample by multiple time steps, with each step corresponding to a network evaluation. In practice, generating a sample is time-consuming due to the thousands of time steps required for the SDE to converge. To address this issue, various generation sampling strategies [21, 32, 41] have been proposed to accelerate the in" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.287, + 0.889, + 0.416 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.487, + 0.424, + 0.691, + 0.554 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.699, + 0.424, + 0.89, + 0.553 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.555, + 0.895, + 0.606 + ], + "angle": 0, + "content": "Figure 1. Top: Visual examples of MDT/DiT [35]. Down: learning progress comparison between DiT and MDT w.r.t. training steps/time on \\(8 \\times \\mathrm{A}100\\) GPUs. MDT has about \\(3 \\times\\) faster learning speed than DiT while achieving superior FID scores." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.631, + 0.895, + 0.728 + ], + "angle": 0, + "content": "ference speed. Nevertheless, improving the training speed of DPMs is less explored but highly desired. Training of DPMs also unavoidably requires a large number of time steps to ensure the convergence of SDEs, making it very computationally expensive, especially in this era where large-scale models [11,35] and data [9,14,44] are often used to improve generation performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.728, + 0.896, + 0.867 + ], + "angle": 0, + "content": "In this work, we first observe that DPMs often struggle to learn the associated relations among object parts in an image. This leads to its slow learning process during training. Specifically, as illustrated in Fig. 1, the classical DPM, DDPM [21] with DiT [35] as the backbone, has learned the shape of a dog at the \\(50\\mathrm{k}\\)-th training step, then learns its one eye and mouth until at the \\(200\\mathrm{k}\\)-th step while missing another eye. Also, the relative position of two ears is not very accurate, even at the \\(300\\mathrm{k}\\)-th step. This learning process reveals that DPMs fail to learn the associated relations" + }, + { + "type": "page_footnote", + "bbox": [ + 0.094, + 0.843, + 0.468, + 0.855 + ], + "angle": 0, + "content": "*This work was done while S. Gao was a research intern at Sea AI Lab." + }, + { + "type": "page_footnote", + "bbox": [ + 0.097, + 0.855, + 0.449, + 0.867 + ], + "angle": 0, + "content": "† Pan Zhou and Ming-Ming Cheng are joint corresponding authors." + }, + { + "type": "list", + "bbox": [ + 0.094, + 0.843, + 0.468, + 0.867 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.465, + 0.888, + 0.506, + 0.899 + ], + "angle": 0, + "content": "23164" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.127, + 0.471, + 0.21 + ], + "angle": 0, + "content": "among semantic parts and independently learn each semantic part. The reason behind this phenomenon is that DPMs maximize the log probability of real data by minimizing the per-pixel prediction loss, which ignores the associated relations among object parts in an image, thus resulting in their slow learning progress." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.211, + 0.474, + 0.515 + ], + "angle": 0, + "content": "Inspired by the above observation, we propose an effective Masked Diffusion Transformer (MDT) to improve the training efficiency of DPMs. MDT proposes a mask latent modeling scheme designed for transformer-based DPMs to explicitly enhance contextual learning ability and improve the associated relation learning among semantic parts in an image. Specifically, following [35, 38], MDT operates the diffusion process in the latent space to save computational costs. It masks certain image tokens and designs an asymmetric diffusion transformer structure to predict masked tokens from unmasked ones in a diffusion generation manner. To this end, the asymmetric structure contains an encoder, a side-interpolyter, and a decoder. The encoder and decoder modify the transformer block in DiT [35] by inserting global and local token position information to help predict masked tokens. The encoder only processes unmasked tokens during training handling all tokens during inference, as there are no masks. So to ensure the decoder always processes all tokens for training prediction or inference generation, a side-interpolyter implemented by a small network aims to predict masked tokens from encoder output during training, and it is removed during inference." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.517, + 0.472, + 0.78 + ], + "angle": 0, + "content": "With the masking latent modeling scheme, our MDT can reconstruct the full information of an image from its contextual incomplete input, learning the associated relations among semantic parts in an image. As shown in Fig. 1, MDT typically generates two eyes of the dog at almost the same training steps, indicating that it correctly learns the associated semantics of an image by utilizing the mask latent modeling scheme. In contrast, DiT [35] cannot easily synthesize a dog with the correct semantic part relations. This comparison shows MDT's superior relation modeling and faster learning ability over DiT. Experimental results demonstrate that MDT achieves superior performance on the image synthesis task, and set the new SOTA on class-conditional image synthesis on the ImageNet dataset, as shown in Fig. 2 and Tab. 2. MDT also enjoys about \\(3 \\times\\) faster learning progress during training than the SOTA DPMs, namely DiT, as demonstrated by Fig. 1 and Tab. 1. We hope our work can inspire more work on speeding up the diffusion training process with unified representation learning." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.782, + 0.435, + 0.795 + ], + "angle": 0, + "content": "The main contributions are summarised as follows:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.811, + 0.47, + 0.868 + ], + "angle": 0, + "content": "- By introducing an effective mask latent modeling scheme, we proposed a masked diffusion transformer method, which, for the first time, explicitly enhances the contextual learning ability of DPMs." + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.124, + 0.887, + 0.324 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.325, + 0.875, + 0.338 + ], + "angle": 0, + "content": "Figure 2. Visualization of images generated by the MDT-XL/2." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.36, + 0.894, + 0.387 + ], + "angle": 0, + "content": "- Experiments show that our method better synthesis images while using much less training time than SOTA." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.407, + 0.645, + 0.421 + ], + "angle": 0, + "content": "2. Related works" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.429, + 0.768, + 0.442 + ], + "angle": 0, + "content": "2.1. Diffusion Probabilistic models" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.451, + 0.895, + 0.756 + ], + "angle": 0, + "content": "Diffusion probabilistic model (DPM) [11,21], also known as score-based model [48,49], is a competitive image synthesis approach. DPMs begin by using an evolving Stochastic Differential Equation (SDE) to gradually add Gaussian noise into real data, transforming a complex data distribution into a Gaussian distribution. Then, it adopts a time-inverted SDE to map a Gaussian noise gradually into a sample by multiple steps. At each sampling time step, a network is utilized to generate the sample along the gradient of the log probability, also known as the score function [50]. The iterative nature of diffusion models can result in high training and inference costs. Efficient sampling strategies [21,23,32,41,46], latent space diffusion [38,51], and multi-resolution cascaded generation [22] have been proposed to reduce the inference cost. Additionally, some training schemes [2, 12] are introduced to improve the diffusion model training, e.g., approximate maximum likelihood training [28, 34, 47], and training loss weighting [26, 27]. We identify the lack of contextual modeling ability in diffusion models. To address this, we propose the mask latent modeling scheme to enhance the contextual representation of diffusion models, which is orthogonal to existing diffusion training schemes." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.763, + 0.773, + 0.776 + ], + "angle": 0, + "content": "2.2. Networks for Diffusion Models" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.784, + 0.895, + 0.868 + ], + "angle": 0, + "content": "The UNet-like [39] network, enhanced by spatial selfattention [42,52] and group normalization [55] is firstly used for diffusion models [21]. Several design improvements, e.g., adding more attention heads [18], BigGAN [4] residual block, and adaptive group normalization, are proposed in [11] to further enhance the generation ability of the UNet." + }, + { + "type": "page_number", + "bbox": [ + 0.465, + 0.888, + 0.505, + 0.899 + ], + "angle": 0, + "content": "23165" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.126, + 0.473, + 0.333 + ], + "angle": 0, + "content": "Recently, due to the broad applicability of transformer networks, several works have attempted to utilize the vision transformer (ViT) structure for diffusion models [1,35,56]. GenViT [56] demonstrates that ViT is capable of image generation but has inferior performance compared to UNet. U-ViT [1] improves ViT by adding long-skip connections and convolutional layers, achieving competitive performance with that of UNet. DiT [35] verifies the scaling ability of ViT on large model sizes and feature resolutions. Our MDT is orthogonal to these diffusion networks as it focuses on contextual representation learning. Moreover, the position-aware designs in MDT reveal that the mask latent modeling scheme benefits from a stronger diffusion network. We will explore further to release the potential of these networks with MDT." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.341, + 0.236, + 0.357 + ], + "angle": 0, + "content": "2.3. Mask Modeling" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.362, + 0.473, + 0.722 + ], + "angle": 0, + "content": "Mask modeling has been proven to be effective in both recognition learning [8, 10, 15, 19] and generative modeling [7, 36]. In the natural language processing (NLP) field, mask modeling was first introduced to enable representation pretraining [10, 36] and language generation [5, 25]. Subsequently, it also proved feasible for vision recognition [3] and generation [7, 16, 57] tasks. In vision recognition, pretraining schemes that utilize mask modeling enable good representation quality [58], scalability [19] and faster convergence [15]. In generative modeling, following the bidirectional generative modeling in NLP, MaskGIT [7] and MUSE [6] use the masked generative transformer to predict randomly masked image tokens for image generation. Similarly, VQ-Diffusion [16] presents a mask-replace diffusion strategy to generate images. In contrast, our MDT aims to enhance the contextual representation of the denoising diffusion transformer [35] with mask latent modeling. This preserves the detail refinement ability of denoising diffusion models by maintaining the diffusion process during inference. To ensure that the mask latent modeling in MDT focuses on representation learning instead of reconstruction, we propose an asymmetrical structure in mask modeling training. As an extra benefit, it enables lower training costs than masked generative models because it skips the masked patches in training instead of replacing masked input patches with a mask token." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.733, + 0.363, + 0.748 + ], + "angle": 0, + "content": "3. Masked Diffusion Transformer" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.756, + 0.472, + 0.868 + ], + "angle": 0, + "content": "Revisit Diffusion Probabilistic Model. For diffusion probabilistic models [11, 45], such as DDPM [21] and DDIM [46], training involves a forward noising process and a reverse denoising process. In the forward noising process, Gaussian noise \\(\\epsilon \\sim \\mathcal{N}(0,\\mathbf{I})\\) is gradually added to the real sample \\(x_0\\) via a discrete SDE formulation [46]. If the time step \\(t\\) is large, \\(x_{t}\\) would be a Gaussian noise. Similarly, the reverse denoising process is a discrete SDE that grad" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.123, + 0.895, + 0.293 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.295, + 0.895, + 0.348 + ], + "angle": 0, + "content": "Figure 3. The overall framework of Masked Diffusion Transformer (MDT). Solid/dotted lines indicate each time step's training/inference process. Masking and side-interpolater are only used during training and are removed during inference." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.368, + 0.895, + 0.493 + ], + "angle": 0, + "content": "ually maps a Gaussian noise into a sample. At each time step, given \\( x_{t} \\), it predicts the next reverse step \\( p_{\\theta}(x_{t - 1}|x_t) \\) via a network. Following [34, 35], the network is trained by optimizing the variational lower-bound \\( L_{\\mathrm{vlb}} \\) of the log-likelihood \\( p_{\\theta}(x_0) \\) [45]. During inference, one can sample a Gaussian noise and then gradually reverses to a sample \\( x_0 \\). Same as [34, 35], we train the diffusion model conditioned with class label \\( c \\), i.e. \\( p_{\\theta}(x_{t - 1}|x_t,c) \\). By default, we use class-conditioned image generation in our experiments." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.5, + 0.611, + 0.513 + ], + "angle": 0, + "content": "3.1. Overview" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.521, + 0.892, + 0.701 + ], + "angle": 0, + "content": "As shown in Fig. 1, DPMs with DiT backbone exhibit slow training convergence due to the slowly learning of the associated relations among semantic parts in an image. To relieve this issue, we propose Masked Diffusion Transformer (MDT), which introduces a mask latent modeling scheme to enhance contextual learning ability explicitly. To this end, as depicted in Fig. 3, MDT consists of 1) a latent masking operation to mask the input image in the latent space, and 2) an asymmetric masking diffusion transformer structure that performs vanilla diffusion process as DPMs, but with masked input. To reduce computational costs, MDT follows LatentDiffusion [38] to perform generative learning in the latent space instead of raw pixel space." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.701, + 0.895, + 0.868 + ], + "angle": 0, + "content": "In the training phase, MDT first encodes an image into a latent space with a pre-trained VAE encoder [38]. Then, MDT adds Gaussian noise into the image latent embedding. The latent masking operation in MDT then patchifies the resulting noisy latent embedding into a sequence of tokens, and masks certain tokens. The remaining unmasked tokens are fed into the asymmetric masking diffusion transformer, as shown in Fig. 4(a), which contains an encoder, a side-interpolater, and a decoder to predict the masked tokens from the unmasked ones. During inference, MDT replaces the side-interpolater with additional position embedding. MDT takes the latent embedding of a Gaussian noise as input to" + }, + { + "type": "page_number", + "bbox": [ + 0.465, + 0.888, + 0.506, + 0.899 + ], + "angle": 0, + "content": "23166" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.127, + 0.47, + 0.154 + ], + "angle": 0, + "content": "generate the denoised latent embedding, which is then passed to a pre-trained VAE decoder [38] for image generation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.155, + 0.471, + 0.416 + ], + "angle": 0, + "content": "The above masking latent modeling scheme in the training phase forces the diffusion model to reconstruct the full information of an image from its contextual incomplete input. Thus, the model is encouraged to learn the relations among image latent tokens, particularly the associated relations among semantic parts in an image. For example, as illustrated in Fig. 3, the model should first understand the correct associated relations among small image parts (tokens) of the dog image. Then, it should generate the masked \"eye\" tokens using other unmasked tokens as contextual information. Furthermore, Fig. 1 shows that MDT often learns to generate the associated semantics of an image at nearly the same pace, such as the generation of the dog's two eyes (two ears) at almost the same training step. While DiT [35] (DDPM with transformer backbone) learns to generate one eye (one ear) initially and then learns to generate another eye (ear) after roughly 100k training steps. This demonstrates the superior learning ability of MDT over DiT in terms of the associated relation learning of image semantics." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.417, + 0.47, + 0.459 + ], + "angle": 0, + "content": "In the following parts, we will introduce the two key components of MDT, 1) a latent masking operation, and 2) an asymmetric masking diffusion transformer structure." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.466, + 0.236, + 0.48 + ], + "angle": 0, + "content": "3.2. Latent Masking" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.487, + 0.471, + 0.556 + ], + "angle": 0, + "content": "Following the Latent diffusion model (LDM) [38], MDT performs generation learning in the latent space instead of raw pixel space to reduce computational costs. In the following, we briefly recall LDM and then introduce our latent masking operation on the latent input." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.572, + 0.47, + 0.711 + ], + "angle": 0, + "content": "Latent diffusion model (LDM). LDM employs a pretrained VAE encoder \\(\\mathbf{E}\\) to encode an image \\(v\\in \\mathbb{R}^{3\\times H\\times W}\\) to a latent embedding \\(z = \\mathbf{E}(v)\\in \\mathbb{R}^{c\\times h\\times w}\\). It gradually adds noise to \\(z\\) in the forward process and then denoises to predict \\(z\\) in the reverse process. Finally, LDM uses a pre-trained VAE decoder \\(\\mathbf{D}\\) to decode \\(z\\) into a high-resolution image \\(v = \\mathbf{D}(z)\\). Both the VAE encoder and decoder are fixed during training and inference. Since \\(h\\) and \\(w\\) are smaller than \\(H\\) and \\(W\\), performing the diffusion process in the low-resolution latent space is more efficient than pixel space." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.727, + 0.47, + 0.867 + ], + "angle": 0, + "content": "Latent masking operation. We first add Gaussian noise to an image's latent embedding \\( z \\) during training. Then following [35], we divide the noisy embedding \\( z \\) into a sequence of \\( p \\times p \\)-sized tokens and concatenate them to a matrix \\( u \\in \\mathbb{R}^{d \\times N} \\), where \\( d \\) is the channel number and \\( N \\) is the number of tokens. Next, we randomly mask tokens with a ratio \\( \\rho \\) and concatenate the remaining tokens as \\( \\hat{u} \\in \\mathbb{R}^{d \\times \\hat{N}} \\), where \\( \\hat{N} = \\rho N \\). Accordingly, we can create a binary mask \\( M \\in \\mathbb{R}^N \\) in which one (zero) denotes the masked (unmasked) tokens. Finally, we feed the tokens \\( \\hat{u} \\)" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.124, + 0.892, + 0.234 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.238, + 0.892, + 0.32 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.327, + 0.892, + 0.473 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.483, + 0.894, + 0.535 + ], + "angle": 0, + "content": "Figure 4. The asymmetric masking diffusion transformer structure in MDT. We modify the DiT [35] by adding a side-interpolater, local relative positional bias, and learnable global position embeddings. The conditional scheme is omitted for simplicity." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.557, + 0.892, + 0.655 + ], + "angle": 0, + "content": "into our diffusion model for processing. We only use tokens \\(\\hat{u}\\) for two reasons. 1) The model should focus on learning semantics instead of predicting the masked tokens. As shown in Sec. 4.3, it achieves better performance than replacing the masked tokens with a learnable mask token and then processing all tokens like [3, 6, 7]; 2) It saves the training cost compared to processing all \\(N\\) tokens." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.663, + 0.879, + 0.678 + ], + "angle": 0, + "content": "3.3. Asymmetric Masking Diffusion Transformer" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.684, + 0.894, + 0.752 + ], + "angle": 0, + "content": "We introduce our asymmetric masking diffusion transformer for joint training of mask latent modeling and diffusion process. As shown in Fig. 4(a), it consists of three components: an encoder, a side-interpolyater, and a decoder, each of which is described in detail below." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.77, + 0.892, + 0.867 + ], + "angle": 0, + "content": "Position-aware encoder and decoder. In MDT, predicting the masked latent tokens from the unmasked tokens requires the position relations of all tokens. To enhance the position information in the model, we propose a positional-aware encoder and decoder that facilitate the learning of the masked latent tokens. Specifically, the encoder and decoder tailor the standard DiT block via adding two types of token position" + }, + { + "type": "page_number", + "bbox": [ + 0.465, + 0.888, + 0.505, + 0.898 + ], + "angle": 0, + "content": "23167" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.126, + 0.47, + 0.154 + ], + "angle": 0, + "content": "information containing \\(N_{1}\\) and \\(N_{2}\\) blocks, as illustrated in Fig. 4(a)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.154, + 0.471, + 0.291 + ], + "angle": 0, + "content": "Firstly, the encoder adds the conventional learnable global position embedding into the noisy latent embedding input. Similarly, the decoder introduces the learnable position embedding into its input but with different training and inference phase approaches. The side-interpolater already uses the learnable global position embedding introduced below during training. During inference, since the side interpolater is discarded (see below), the decoder explicitly adds the position embedding into its input to enhance positional information." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.292, + 0.471, + 0.348 + ], + "angle": 0, + "content": "Secondly, as depicted in Fig. 4(b), the encoder and decoder add a local relative positional bias [30] to each head in each block when computing the attention score of the self-attention [53]:" + }, + { + "type": "equation", + "bbox": [ + 0.104, + 0.354, + 0.443, + 0.387 + ], + "angle": 0, + "content": "\\[\n\\operatorname {A t t e n t i o n} (Q, K, V) = \\operatorname {S o f t m a x} \\left(\\frac {Q K ^ {\\top}}{\\sqrt {d _ {k}}} + B _ {r}\\right) V,\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.392, + 0.47, + 0.503 + ], + "angle": 0, + "content": "where \\(Q\\), \\(K\\), and \\(V\\), respectively denote the query, key, and value in the self-attention module, \\(d_k\\) is the dimension of the key, and \\(B_r \\in \\mathbb{R}^{N \\times N}\\) is the relative positional bias. \\(B_r\\) is selected by the relative positional difference between the \\(i\\)-th position and other positions, which is updated during training. The local relative positional bias helps to capture the relative relations among tokens, facilitating the masking of latent modeling." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.504, + 0.471, + 0.627 + ], + "angle": 0, + "content": "The encoder takes the unmasked noisy latent embedding provided by our latent masking operation and feeds its output into the side-interpolater/decoder during training/inference. For the decoder, its input is the output of the side-interpolater for training or the combination of the encoder output and the learnable position embedding for inference. During training, the encoder and decoder, respectively, handle unmasked tokens and full tokens. Thus, we name our model the \"asymmetric\" model." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.644, + 0.47, + 0.796 + ], + "angle": 0, + "content": "Side-interpolater. As shown in Fig. 3, during training, for efficiency and better performance, the encoder only processes the unmasked tokens \\(\\hat{u}\\). While in the inference phase, the encoder handles all tokens \\(u\\) due to the lack of masks. This means that there is a big difference in the encoder output (i.e., decoder input) during training and inference, at least in terms of token number. To ensure the decoder always processes all tokens for training prediction or inference generation, a side-interpolyter implemented by a small network aims to predict masked tokens from encoder output during training and would be removed during inference." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.796, + 0.47, + 0.867 + ], + "angle": 0, + "content": "In the training phase, the encoder processes the unmasked tokens to obtain its output token embedding \\(\\hat{q} \\in \\mathbb{R}^{d \\times \\hat{N}}\\). Then, as shown in Fig. 4(c), the side-interpolater first fills the masked positions, indicated by the mask \\(M\\) defined in Sec. 3.2, by a shared learnable mask token, and also adds" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.126, + 0.894, + 0.265 + ], + "angle": 0, + "content": "a learnable positional embedding to obtain an embedding \\( q \\in \\mathbb{R}^{d \\times N} \\). Next, we use a basic encoder block to process \\( q \\) to predict an interpolated embedding \\( \\hat{k} \\). The \\( \\hat{k} \\) tokens denote the predicted tokens. Finally, we use a masked shortcut connection to combine prediction \\( \\hat{k} \\) and \\( q \\) as \\( k = M \\cdot q + (1 - M) \\cdot \\hat{k} \\). In summary, for masked tokens, we use the prediction by side-interpolyter. For unmasked tokens, we still adopt the corresponding tokens in \\( q \\). This can 1) boost the consistency between training and inference phases, 2) eliminates the mask-reconstruction process in the decoder." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.265, + 0.895, + 0.375 + ], + "angle": 0, + "content": "Since there are no masks during inference, the side-interpolater is replaced by a position embedding operation, which adds the learnable position embeddings of the side-interpolater, learned during training. This ensures the decoder always processes all tokens and uses the same learnable position embeddings for training prediction or inference generation, thus having better image generation performance." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.383, + 0.605, + 0.398 + ], + "angle": 0, + "content": "3.4. Training" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.404, + 0.895, + 0.57 + ], + "angle": 0, + "content": "During training, we feed both full latent embedding \\( u \\) and the masked latent embedding \\( \\hat{u} \\) to the diffusion model. We observe that only using masked latent embedding makes the model focus too much on masked region reconstruction, while ignoring the diffusion training. Full/masked latent inputs are independently sent to the network, and the training objectives optimize the variational lower-bound, as in [34, 35]. Due to the asymmetrical masking structure, the extra costs for using masked latent embedding are small. This is also demonstrated by Fig. 1, which shows that MDT still achieves about \\( 3 \\times \\) faster learning progress than previous SOTA DiT in total training hours." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.582, + 0.633, + 0.597 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.604, + 0.66, + 0.619 + ], + "angle": 0, + "content": "4.1. Implementation" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.625, + 0.892, + 0.654 + ], + "angle": 0, + "content": "We give the implementation details of MDT, including model architecture, training details, and evaluation metrics." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.669, + 0.895, + 0.837 + ], + "angle": 0, + "content": "Model architecture. We follow DiT [35] to set the total block number (i.e., \\(N_{1} + N_{2}\\)), token number, and channel numbers of the diffusion transformer of MDT. As DiT reveals stronger synthesis performance when using a smaller patch size, we also use a patch size \\(p = 2\\) by default, denoted by MDT-/2. Moreover, We also follow DiT's parameters to design MDT for getting its small-, base-, and xlarge-sized model, denoted by MDT-S/B/XL. Same as LatentDiffusion [38] and DiT, MDT adopts the fixed \\(\\mathrm{VAE}^{1}\\) provided by the Stable Diffusion to encode/decode the image/latent tokens by default. The VAE encoder has a downsampling ratio of \\(1 / 8\\), and a feature channel dimension of 4, e.g., an image" + }, + { + "type": "page_footnote", + "bbox": [ + 0.5, + 0.843, + 0.894, + 0.867 + ], + "angle": 0, + "content": "1The model is downloaded in https://huggingface.co/stabilityai/sd-vae-ft-mse" + }, + { + "type": "page_number", + "bbox": [ + 0.465, + 0.888, + 0.506, + 0.899 + ], + "angle": 0, + "content": "23168" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.079, + 0.124, + 0.468, + 0.343 + ], + "angle": 0, + "content": "
MethodImage Res.Training Steps (k)FID-50K↓
DiT-S/2256×25640068.40
MDT-S/2256×25630057.01
MDT-S/2256×25640053.46
MDT-S/2256×256200044.14
MDT-S/2256×256350041.37
DiT-B/2256×25640043.47
MDT-B/2256×25640034.33
MDT-B/2256×256350020.45
DiT-XL/2256×25640019.47
DiT-XL/2256×256235210.67
DiT-XL/2256×25670009.62
MDT-XL/2256×25640016.42
MDT-XL/2256×25613009.60
MDT-XL/2256×25635006.65
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.348, + 0.47, + 0.388 + ], + "angle": 0, + "content": "Table 1. Comparison between DiT [35] and MDT under different model sizes and training steps on ImageNet \\(256\\times 256\\). DiT results are obtained from DiT reported results." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.41, + 0.47, + 0.438 + ], + "angle": 0, + "content": "of size \\(256 \\times 256 \\times 3\\) is encoded into a latent embedding of size \\(32 \\times 32 \\times 4\\)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.457, + 0.47, + 0.569 + ], + "angle": 0, + "content": "Training details. Following [35], all models are trained by AdamW [31] optimizer of 3e-4 learning rate, 256 batch size, and without weight decay on ImageNet [9] with an image resolution of \\(256 \\times 256\\). We set the mask ratio as 0.3 and \\(N_{2} = 2\\). Following the training settings in DiT, we set the maximum step in training to 1000 and use the linear variance schedule with a range from \\(10^{-4}\\) to \\(2 \\times 10^{-2}\\). Other settings are also aligned with DiT." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.587, + 0.471, + 0.752 + ], + "angle": 0, + "content": "Evaluation. We evaluate models with commonly used metrics, i.e. Frechet Inception Distance (FID) [20], sFID [33], Inception Score (IS) [40], Precision and Recall [29]. The FID is used as the major metric as it measures both diversity and fidelity. sFID improves upon FID by evaluating at the spatial level. As a complement, IS and Precision are used for measuring fidelity, and Recall is used to measure diversity. For fair comparisons, we follow [35] to use the TensorFlow evaluation suite from ADM [11] and report FID-50K with 250 DDPM sampling steps. Unless specified otherwise, we report the FID scores without the classifier-free guidance [23]." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.762, + 0.269, + 0.777 + ], + "angle": 0, + "content": "4.2. Comparison Results" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.784, + 0.47, + 0.867 + ], + "angle": 0, + "content": "Performance comparison. Tab. 1 compares our MDT with the SOTA DiT under different model sizes. It is evident that MDT achieves higher FID scores for all model scales with fewer training costs. The parameters and inference cost of MDTs are similar to DiT, since the extra modules in MDT are negligible as introduced in Sec. 3.1. For small models," + }, + { + "type": "table", + "bbox": [ + 0.501, + 0.125, + 0.892, + 0.468 + ], + "angle": 0, + "content": "
MethodCost(ITer×BS)FID↓sFID↓IS↑Prec.↑Rec.↑
DCTrans. [33]-36.51--0.360.67
VQVAE-2 [37]-31.11--0.360.57
VQGAN [13]-15.7878.3---
BigGAN-deep [4]-6.957.36171.40.870.28
StyleGAN [43]-2.304.02265.120.780.53
Impr. DDPM [34]-12.26--0.700.62
MaskGIT [7]1387k×2566.18-182.10.800.51
CDM [22]-4.88-158.71--
ADM [11]1980k×25610.946.02100.980.690.63
LDM-8 [38]4800k×6415.51-79.030.650.63
LDM-4178k×120010.56-103.490.710.62
DiT-XL/2 [35]7000k×2569.626.85121.500.670.67
MDT2500k×2567.414.95121.220.720.64
MDT3500k×2566.464.92131.700.720.63
MDT6500k×2566.235.23143.020.710.65
ADM-G [11]1980k×2564.595.25186.700.820.52
ADM-G, U1980k×2563.946.14215.840.830.53
LDM-8-G [38]4800k×647.76-209.520.840.35
LDM-4-G178k×12003.60-247.670.870.48
U-ViT-G [1]300k×10243.40----
DiT-XL/2-G [35]7000k×2562.274.60278.240.830.57
MDT-G2500k×2562.154.52249.270.820.58
MDT-G3500k×2562.024.46263.770.820.60
MDT-G6500k×2561.794.57283.010.810.61
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.48, + 0.892, + 0.545 + ], + "angle": 0, + "content": "Table 2. Comparison with existing methods on class-conditional image generation with the ImageNet \\(256 \\times 256\\) dataset. -G denotes the results with classifier-free guidance [23]. Results of MDT-XL/2 model are given for comparison. Compared results are obtained from their papers." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.573, + 0.894, + 0.685 + ], + "angle": 0, + "content": "MDT-S/2 trained with 300k steps outperforms the DiT-S/2 trained with 400k steps by a large margin on FID (57.01 vs. 68.40). More importantly, MDT-S/2 trained with 2000k steps achieves similar performance with a larger model DiT-B/2 trained with a similar computational budget. For the largest model, MDT-XL/2 trained with 1300k steps outperforms DiT-XL/2 trained with 7000k steps on FID (9.60 vs. 9.62), achieving about \\(5 \\times\\) faster training progress." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.688, + 0.895, + 0.867 + ], + "angle": 0, + "content": "We also compare the class-conditional image generation performance of MDT with existing methods in Tab. 2. To make fair comparisons with DiT, we also use the EMA weights of VAE decoder in this table. Under class-conditional settings, MDT with half training iterations outperforms DiT by a large margin, e.g., 6.83 vs 9.62 in FID. Following previous works [1, 11, 35, 38], we utilize an improved classifier-free guidance [23] with a power-cosine weight scaling to trade off between precision and recall during class-conditional sampling. MDT achieves superior performance over previous SOTA DiT and other methods with the FID score of 1.81, setting a new SOTA for class-conditional image generation. Similar to DiT, we never" + }, + { + "type": "page_number", + "bbox": [ + 0.465, + 0.888, + 0.505, + 0.899 + ], + "angle": 0, + "content": "23169" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.124, + 0.462, + 0.253 + ], + "angle": 0, + "content": "
Mask RatioFID↓sFID↓IS↑Precision↑Recall↑
0.151.6010.2326.650.440.60
0.251.4410.0926.750.440.58
0.350.2610.0827.610.450.60
0.450.8810.2127.440.450.60
0.551.579.9227.140.440.60
0.653.2010.3626.550.440.61
0.752.9010.0326.510.440.61
0.853.7310.1525.550.430.61
" + }, + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.26, + 0.468, + 0.284 + ], + "angle": 0, + "content": "Table 3. Effect of different masking ratios. MDT-S/2 trained with 600k iterations." + }, + { + "type": "table", + "bbox": [ + 0.081, + 0.295, + 0.462, + 0.386 + ], + "angle": 0, + "content": "
Decoder pos.FID↓sFID↓IS↑Precision↑Recall↑
Last051.059.9727.310.440.60
Last150.969.9027.630.450.60
Last250.2610.0827.610.450.60
Last451.6710.1226.910.450.60
Last652.6410.3626.460.440.60
" + }, + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.393, + 0.468, + 0.418 + ], + "angle": 0, + "content": "Table 4. Effect of position of side-interpolater. MDT-S/2 models contain 12 blocks and are trained with 600k iterations." + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.44, + 0.468, + 0.467 + ], + "angle": 0, + "content": "observe the model has saturated FID scores when continuing training." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.486, + 0.47, + 0.637 + ], + "angle": 0, + "content": "Convergence speed. Fig. 1 compares the performance of the DiT/S-2 baseline and MDT/S-2 under different training steps and training time on \\(8 \\times \\mathrm{A}100\\) GPUs. Because of the stronger contextual learning ability, MDT achieves better performance with faster generation learning speed. MDT enjoys about \\(3 \\times\\) faster learning speed in terms of both training steps and training time. For example, MDT-S/2 trained with about 33 hours (400k steps) achieves superior performance than DiT-S/2 trained with about 100 hours (1500k steps). This reveals that contextual learning is vital for faster generation learning of diffusion models." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.647, + 0.182, + 0.66 + ], + "angle": 0, + "content": "4.3. Ablation" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.669, + 0.468, + 0.709 + ], + "angle": 0, + "content": "In this part, we conduct ablation to verify the designs in MDT. We report the results of MDT-S/2 model and use FID-50k as the evaluation metric unless otherwise stated." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.728, + 0.47, + 0.866 + ], + "angle": 0, + "content": "Masking ratio. The masking ratio determines the number of input patches that can be processed during training. We give the comparison of using different masking ratios in Tab. 3. The best masking ratio for MDT-S/2 is \\(30\\%\\), which is quite different from the masking ratio used for recognition models, e.g. \\(75\\%\\) masking ratio in MAE [19]. We assume that the image generation requires learning more details from more patches for high-quality synthesis, while recognition models only need the most essential patches to infer semantics." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.126, + 0.892, + 0.305 + ], + "angle": 0, + "content": "Side-interpolater position. To meet the high-quality image generation requirements of the diffusion model, the side-interpolater is placed in the middle of the network instead of the end of the network in recognition models [3, 19]. Tab. 4, presents the comparison of placing the side-interpolater at different positions of the MDT-S model with 12 blocks. The results show that placing the side-interpolater before the last two blocks achieves the best FID score, whereas placing it at the end of the network like recognition models impairs the performance. Placing the side-interpolater at the early stages of the network also harm the performance, indicating the mask latent modeling is beneficial to most stages in the diffusion models." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.325, + 0.893, + 0.545 + ], + "angle": 0, + "content": "Asymmetric vs. Symmetric architecture in masking. Unlike the masked generation works [6, 7], e.g., MaskGIT, that utilize the masking scheme to generate images, MDT focuses on improving diffusion models with contextual learning ability via the masking latent modeling. Therefore, we use an asymmetric architecture to only process the unmasked tokens in the diffusion model encoder. We compare the asymmetric architecture in MDT and the symmetrical architecture [7] that processes full input with masked tokens replaced by a learnable mask token. As shown in Tab. 5a, the asymmetric architecture in MDT has an FID of 50.26, outperforming the FID of 51.56 achieved by the symmetric architecture. The asymmetric architecture further reduces the training cost and allows the diffusion model to focus on learning contextual information instead of reconstructing masked tokens." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.565, + 0.892, + 0.662 + ], + "angle": 0, + "content": "Effect of side-interpolater. The side-interpolater in MDT predicts the masked tokens, allowing the diffusion model to learn more semantics and maintain consistency in decoder inputs during training and inference. We compare the performance with/without the side-interpolater in Tab. 5b, and observe a gain of 1.34 in FID when using the side-interpolater, proving its effectiveness." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.682, + 0.892, + 0.778 + ], + "angle": 0, + "content": "Masked shortcut in side-interpolater. The masked shortcut ensures that the side-interpolater only predicts the masked tokens from unmasked ones. Tab. 5c shows that using the masked shortcut enhances the FID from 50.91 to 50.26, indicating that restricting side-interpolater to only predict masked tokens helps the diffusion model achieve stronger performance." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.797, + 0.892, + 0.867 + ], + "angle": 0, + "content": "Full and masked latent tokens. In MDT, both the full and masked latent embeddings are fed into the diffusion model during training. In comparison, we give the results trained by only using full/masked latent embeddings as shown in Tab. 5d, where the computational cost is aligned for" + }, + { + "type": "page_number", + "bbox": [ + 0.465, + 0.888, + 0.505, + 0.899 + ], + "angle": 0, + "content": "23170" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.091, + 0.135, + 0.35, + 0.189 + ], + "angle": 0, + "content": "
Asymmetric stru.FID-50k↓
×51.56
✓50.26
" + }, + { + "type": "table_caption", + "bbox": [ + 0.103, + 0.191, + 0.333, + 0.203 + ], + "angle": 0, + "content": "(a) Effect of asymmetric masking structure." + }, + { + "type": "table", + "bbox": [ + 0.356, + 0.135, + 0.617, + 0.189 + ], + "angle": 0, + "content": "
Side-interpolaterFID-50k↓
×51.60
✓50.26
" + }, + { + "type": "table_caption", + "bbox": [ + 0.406, + 0.191, + 0.564, + 0.203 + ], + "angle": 0, + "content": "(b) Effect of side-interpolater." + }, + { + "type": "table", + "bbox": [ + 0.623, + 0.135, + 0.884, + 0.189 + ], + "angle": 0, + "content": "
Masked shortcutFID-50k↓
×50.91
✓50.26
" + }, + { + "type": "table_caption", + "bbox": [ + 0.673, + 0.191, + 0.83, + 0.202 + ], + "angle": 0, + "content": "(c) Effect of masked shortcut." + }, + { + "type": "table", + "bbox": [ + 0.091, + 0.215, + 0.346, + 0.28 + ], + "angle": 0, + "content": "
Latent typeFID-50k↓
Full+Masked50.26
Full52.30
Masked76.63
" + }, + { + "type": "table_caption", + "bbox": [ + 0.091, + 0.283, + 0.341, + 0.295 + ], + "angle": 0, + "content": "(d) Using full/masked latent under aligned cost." + }, + { + "type": "table", + "bbox": [ + 0.356, + 0.215, + 0.616, + 0.28 + ], + "angle": 0, + "content": "
Sup. partsFID-50k↓
All50.26
Masked58.35
" + }, + { + "type": "table_caption", + "bbox": [ + 0.402, + 0.283, + 0.564, + 0.295 + ], + "angle": 0, + "content": "(e) Supervision on token parts." + }, + { + "type": "table", + "bbox": [ + 0.623, + 0.215, + 0.884, + 0.28 + ], + "angle": 0, + "content": "
NumberFID-50k↓
150.26
251.77
351.96
" + }, + { + "type": "table_caption", + "bbox": [ + 0.643, + 0.283, + 0.861, + 0.295 + ], + "angle": 0, + "content": "(f) Number of blocks in side-interpolator." + }, + { + "type": "table", + "bbox": [ + 0.091, + 0.306, + 0.349, + 0.359 + ], + "angle": 0, + "content": "
IS Pos. embed.FID-50k↓
×51.58
✓50.26
" + }, + { + "type": "table_caption", + "bbox": [ + 0.107, + 0.362, + 0.327, + 0.374 + ], + "angle": 0, + "content": "(g) Effect of positional embeddings in SI." + }, + { + "type": "table", + "bbox": [ + 0.356, + 0.306, + 0.615, + 0.359 + ], + "angle": 0, + "content": "
Learnable pos.FID-50k↓
×50.80
✓50.26
" + }, + { + "type": "table_caption", + "bbox": [ + 0.362, + 0.362, + 0.604, + 0.374 + ], + "angle": 0, + "content": "(h) Effect of learnable positional embeddings." + }, + { + "type": "table", + "bbox": [ + 0.622, + 0.306, + 0.884, + 0.359 + ], + "angle": 0, + "content": "
Relative pos. biasFID-50k↓
×53.56
✓50.26
" + }, + { + "type": "table_caption", + "bbox": [ + 0.657, + 0.362, + 0.844, + 0.374 + ], + "angle": 0, + "content": "(i) Effect of relative positional bias." + }, + { + "type": "table_caption", + "bbox": [ + 0.258, + 0.377, + 0.71, + 0.389 + ], + "angle": 0, + "content": "Table 5. Ablation study on MDT-S/2. Models are trained for 600k iterations." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.413, + 0.47, + 0.496 + ], + "angle": 0, + "content": "fair comparisons. Trained with both full and masked latent leads to clear gain over two competitors. While using only the masked latent embeddings results in slow convergence, which we attribute to the training/inference inconsistency as the inference in MDT is a diffusion process instead of the masked reconstruction process." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.513, + 0.47, + 0.638 + ], + "angle": 0, + "content": "Loss on all tokens. By default, we calculate the loss on both masked and unmasked latent embeddings. In comparison, mask modeling for recognition models commonly calculates loss on masked tokens [3, 19]. Tab. 5e shows that calculating the loss on all tokens is much better than on masked tokens. We assume that this is because generative models require stronger consistency among patches than recognition models do, since details are vital for high-quality image synthesis." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.655, + 0.47, + 0.752 + ], + "angle": 0, + "content": "Block number in side-interpolater. We compare the performance of different numbers of blocks in the side-interpolater in Tab. 5f. The default setting of 1 block achieves the best performance, and the FID worsens with an increase in block number. This result is consistent with our motivation that side-interpolater should not learn too much information other than interpolating the masked representations." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.77, + 0.471, + 0.867 + ], + "angle": 0, + "content": "Positional-aware enhancement. To further release the potential of mask latent modeling, we enhance the DiT baseline with stronger positional awareness ability, i.e. learnable positional embeddings and the relative positional bias in basic blocks. Tab. 5g shows the positional embeddings in side-interpolator improves the FID from 51.58 to 50.26, indicating the positional embedding is vital for the side-interpolator." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.413, + 0.893, + 0.552 + ], + "angle": 0, + "content": "Also, enables the training of positional embeddings brings the gain in FID as revealed in Tab. 5h. In Tab. 5i, the relative positional bias in the basic blocks significantly improves the FID from 53.56 to 50.26, showing the relative positional modeling ability is essential for diffusion models to obtain the contextual representation ability and generate high-quality images. Therefore, the positional awareness ability in diffusion model structure is required to accompany the masked latent modeling, playing a key role in improving performance." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.561, + 0.619, + 0.575 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.585, + 0.893, + 0.764 + ], + "angle": 0, + "content": "This work proposes a masked diffusion transformer to enhance the contextual representation and improve the relation learning among image semantics for DPMs. We introduce an effective mask latent modeling scheme into DPMs and also accordingly designs an asymmetric masking diffusion transformer structure. Experiments show that our masked diffusion transformer enjoys higher performance on image synthesis and largely improves the learning progress during training, achieving the new SOTA for image synthesis on the ImageNet dataset. We hope our initial exploration of contextual learning for generative modeling can facilitate more work on unifying the representation learning for recognition and generative models." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.775, + 0.664, + 0.79 + ], + "angle": 0, + "content": "Acknowledgement." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.798, + 0.894, + 0.867 + ], + "angle": 0, + "content": "This research was supported by the NSFC (NO. 62225604) and the Fundamental Research Funds for the Central Universities (Nankai University, 070-63233089). The Supercomputing Center of Nankai University supports computation." + }, + { + "type": "page_number", + "bbox": [ + 0.465, + 0.888, + 0.504, + 0.898 + ], + "angle": 0, + "content": "23171" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.125, + 0.173, + 0.139 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.149, + 0.47, + 0.188 + ], + "angle": 0, + "content": "[1] Fan Bao, Chongxuan Li, Yue Cao, and Jun Zhu. All are worth words: a vit backbone for score-based diffusion models. arXiv preprint arXiv:2209.12152, 2022. 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.19, + 0.472, + 0.24 + ], + "angle": 0, + "content": "[2] Fan Bao, Chongxuan Li, Jiacheng Sun, Jun Zhu, and Bo Zhang. Estimating the optimal covariance with imperfect mean in diffusion probabilistic models. In Int. Mach. Learn., 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.243, + 0.472, + 0.28 + ], + "angle": 0, + "content": "[3] Hangbo Bao, Li Dong, and Furu Wei. Beit: Bert pre-training of image transformers. Int. Conf. Learn. Represent., 2022. 3, 4, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.283, + 0.472, + 0.322 + ], + "angle": 0, + "content": "[4] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. Int. Conf. Learn. Represent., 2019. 1, 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.324, + 0.472, + 0.386 + ], + "angle": 0, + "content": "[5] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, et al. Language models are few-shot learners. Adv. Neural Inform. Process. Syst., 33:1877-1901, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.389, + 0.472, + 0.453 + ], + "angle": 0, + "content": "[6] Huiwen Chang, Han Zhang, Jarred Barber, AJ Maschinot, Jose Lezama, Lu Jiang, Ming-Hsuan Yang, Kevin Murphy, William T Freeman, Michael Rubinstein, et al. Muse: Text-to-image generation via masked generative transformers. arXiv preprint arXiv:2301.00704, 2023. 3, 4, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.455, + 0.472, + 0.505 + ], + "angle": 0, + "content": "[7] Huiwen Chang, Han Zhang, Lu Jiang, Ce Liu, and William T Freeman. Maskgit: Masked generative image transformer. In IEEE Conf. Comput. Vis. Pattern Recog., pages 11315-11325, 2022. 3, 4, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.508, + 0.472, + 0.558 + ], + "angle": 0, + "content": "[8] Gong Cheng, Ruimin Li, Chunbo Lang, and Junwei Han. Task-wise attention guided part complementary learning for few-shot image classification. Science China Information Sciences, 64:1-14, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.561, + 0.472, + 0.599 + ], + "angle": 0, + "content": "[9] J. Deng, W. Dong, R. Socher, L.-J. Li, K. Li, and L. Fei-Fei. Imagenet: A large-scale hierarchical image database. In IEEE Conf. Comput. Vis. Pattern Recog., 2009. 1, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.602, + 0.472, + 0.64 + ], + "angle": 0, + "content": "[10] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. NAACL, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.642, + 0.472, + 0.679 + ], + "angle": 0, + "content": "[11] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Adv. Neural Inform. Process. Syst., 34:8780-8794, 2021. 1, 2, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.682, + 0.472, + 0.72 + ], + "angle": 0, + "content": "[12] Tim Dockhorn, Arash Vahdat, and Karsten Kreis. Score-based generative modeling with critically-damped Langevin diffusion. In Int. Conf. Learn. Represent., 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.723, + 0.472, + 0.773 + ], + "angle": 0, + "content": "[13] Patrick Esser, Robin Rombach, and Bjorn Ommer. Taming transformers for high-resolution image synthesis. In IEEE Conf. Comput. Vis. Pattern Recog., pages 12873-12883, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.776, + 0.472, + 0.825 + ], + "angle": 0, + "content": "[14] Shanghua Gao, Zhong-Yu Li, Ming-Hsuan Yang, Ming-Ming Cheng, Junwei Han, and Philip Torr. Large-scale unsupervised semantic segmentation. IEEE Trans. Pattern Anal. Mach. Intell., 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.828, + 0.472, + 0.867 + ], + "angle": 0, + "content": "[15] Shanghua Gao, Pan Zhou, Ming-Ming Cheng, and Shuicheng Yan. Towards sustainable self-supervised learning. arXiv preprint arXiv:2210.11016, 2022. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.149, + 0.472, + 0.867 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.127, + 0.894, + 0.189 + ], + "angle": 0, + "content": "[16] Shuyang Gu, Dong Chen, Jianmin Bao, Fang Wen, Bo Zhang, Dongdong Chen, Lu Yuan, and Baining Guo. Vector quantized diffusion model for text-to-image synthesis. In IEEE Conf. Comput. Vis. Pattern Recog., pages 10696-10706, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.192, + 0.894, + 0.242 + ], + "angle": 0, + "content": "[17] Yuchao Gu, Xintao Wang, Yixiao Ge, Ying Shan, Xiaohu Qie, and Mike Zheng Shou. Rethinking the objectives of vector-quantized tokenizers for image synthesis. arXiv preprint arXiv:2212.03185, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.244, + 0.894, + 0.307 + ], + "angle": 0, + "content": "[18] Meng-Hao Guo, Tian-Xing Xu, Jiang-Jiang Liu, Zheng-Ning Liu, Peng-Tao Jiang, Tai-Jiang Mu, Song-Hai Zhang, Ralph R. Martin, Ming-Ming Cheng, and Shi-Min Hu. Attention mechanisms in computer vision: A survey. Computational Visual Media, 8(3):331-368, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.309, + 0.894, + 0.358 + ], + "angle": 0, + "content": "[19] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollar, and Ross Girshick. Masked autoencoders are scalable vision learners. In IEEE Conf. Comput. Vis. Pattern Recog., pages 16000-16009, 2022. 3, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.361, + 0.894, + 0.411 + ], + "angle": 0, + "content": "[20] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Adv. Neural Inform. Process. Syst., 30, 2017. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.412, + 0.894, + 0.45 + ], + "angle": 0, + "content": "[21] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Adv. Neural Inform. Process. Syst., 33:6840-6851, 2020. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.452, + 0.894, + 0.502 + ], + "angle": 0, + "content": "[22] Jonathan Ho, Chitwan Sahara, William Chan, David J Fleet, Mohammad Norouzi, and Tim Salimans. Cascaded diffusion models for high fidelity image generation. J. Mach. Learn. Res., 23(47):1-33, 2022. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.504, + 0.894, + 0.529 + ], + "angle": 0, + "content": "[23] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. NeurIPS Workshop, 2021. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.53, + 0.894, + 0.579 + ], + "angle": 0, + "content": "[24] Myeonghun Jeong, Hyeongju Kim, Sung Jun Cheon, Byoung Jin Choi, and Nam Soo Kim. Diff-tps: A denoising diffusion model for text-to-speech. In INTERSPEECH, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.582, + 0.894, + 0.632 + ], + "angle": 0, + "content": "[25] Ge-Peng Ji, Mingchen Zhuge, Dehong Gao, Deng-Ping Fan, Christos Sakaridis, and Luc Van Gool. Masked vision-language transformer in fashion. Machine Intelligence Research, 20(3):421-434, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.634, + 0.894, + 0.672 + ], + "angle": 0, + "content": "[26] Tero Karras, Miika Aittala, Timo Aila, and Samuli Laine. Elucidating the design space of diffusion-based generative models. In Adv. Neural Inform. Process. Syst., 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.673, + 0.894, + 0.723 + ], + "angle": 0, + "content": "[27] Dongjun Kim, Seungjae Shin, Kyungwoo Song, Wanmo Kang, and Il-Chul Moon. Soft truncation: A universal training technique of score-based diffusion model for high precision score estimation. In Int. Mach. Learn., 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.725, + 0.894, + 0.762 + ], + "angle": 0, + "content": "[28] Diederik Kingma, Tim Salimans, Ben Poole, and Jonathan Ho. Variational diffusion models. Adv. Neural Inform. Process. Syst., 34:21696-21707, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.764, + 0.894, + 0.814 + ], + "angle": 0, + "content": "[29] Tuomas Kynkänniemi, Tero Karras, Samuli Laine, Jaakko Lehtinen, and Timo Aila. Improved precision and recall metric for assessing generative models. Adv. Neural Inform. Process. Syst., 32, 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.816, + 0.894, + 0.867 + ], + "angle": 0, + "content": "[30] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Int. Conf. Comput. Vis., pages 10012-10022, 2021. 5" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.127, + 0.894, + 0.867 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.465, + 0.888, + 0.505, + 0.899 + ], + "angle": 0, + "content": "23172" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.127, + 0.469, + 0.153 + ], + "angle": 0, + "content": "[31] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. Int. Conf. Learn. Represent., 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.154, + 0.47, + 0.205 + ], + "angle": 0, + "content": "[32] Cheng Lu, Yuhao Zhou, Fan Bao, Jianfei Chen, Chongxuan Li, and Jun Zhu. Dpm-solver: A fast ode solver for diffusion probabilistic model sampling in around 10 steps. Adv. Neural Inform. Process. Syst., 2022. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.206, + 0.471, + 0.243 + ], + "angle": 0, + "content": "[33] Charlie Nash, Jacob Menick, Sander Dieleman, and Peter W Battaglia. Generating images with sparse representations. Int. Mach. Learn., 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.245, + 0.471, + 0.283 + ], + "angle": 0, + "content": "[34] Alexander Quinn Nichol and Prafulla Dhariwal. Improved denoising diffusion probabilistic models. In Int. Mach. Learn., pages 8162-8171. PMLR, 2021. 2, 3, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.284, + 0.471, + 0.322 + ], + "angle": 0, + "content": "[35] William Peebles and Saining Xie. Scalable diffusion models with transformers. arXiv preprint arXiv:2212.09748, 2022. 1, 2, 3, 4, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.323, + 0.471, + 0.361 + ], + "angle": 0, + "content": "[36] Alec Radford, Karthik Narasimhan, Tim Salimans, Ilya Sutskever, et al. Improving language understanding by generative pre-training, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.362, + 0.471, + 0.4 + ], + "angle": 0, + "content": "[37] Ali Razavi, Aaron Van den Oord, and Oriol Vinyals. Generating diverse high-fidelity images with vq-vae-2. Adv. Neural Inform. Process. Syst., 32, 2019. 1, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.401, + 0.471, + 0.464 + ], + "angle": 0, + "content": "[38] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In IEEE Conf. Comput. Vis. Pattern Recog., pages 10684-10695, 2022. 1, 2, 3, 4, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.466, + 0.471, + 0.516 + ], + "angle": 0, + "content": "[39] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In Int. Conf. Med Image Comput Comput Assist Interv., pages 234-241. Springer, 2015. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.518, + 0.471, + 0.567 + ], + "angle": 0, + "content": "[40] Tim Salimans, Ian Goodfellow, Wojciech Zaremba, Vicki Cheung, Alec Radford, and Xi Chen. Improved techniques for training gans. Adv. Neural Inform. Process. Syst., 29, 2016. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.569, + 0.471, + 0.607 + ], + "angle": 0, + "content": "[41] Tim Salimans and Jonathan Ho. Progressive distillation for fast sampling of diffusion models. Int. Conf. Learn. Represent., 2022. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.608, + 0.471, + 0.659 + ], + "angle": 0, + "content": "[42] Tim Salimans, Andrej Karpathy, Xi Chen, and Diederik P Kingma. PixelCNN++: Improving the pixelCNN with discretized logistic mixture likelihood and other modifications. In Int. Conf. Learn. Represent., 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.66, + 0.471, + 0.699 + ], + "angle": 0, + "content": "[43] Axel Sauer, Katja Schwarz, and Andreas Geiger. Stylegan-xl: Scaling stylegan to large diverse datasets. In ACM SIGGRAPH 2022 conference proceedings, pages 1-10, 2022. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.7, + 0.471, + 0.774 + ], + "angle": 0, + "content": "[44] Christoph Schuhmann, Romain Beaumont, Richard Vencu, Cade Gordon, Ross Wightman, Mehdi Cherti, Theo Coombes, Aarush Katta, Clayton Mullis, Mitchell Wortsman, et al. Laion-5b: An open large-scale dataset for training next generation image-text models. Adv. Neural Inform. Process. Syst., 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.776, + 0.471, + 0.827 + ], + "angle": 0, + "content": "[45] Jascha Sohl-Dickstein, Eric Weiss, Niru Maheswaranathan, and Surya Ganguli. Deep unsupervised learning using nonequilibrium thermodynamics. In Int. Mach. Learn., pages 2256-2265. PMLR, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.828, + 0.471, + 0.866 + ], + "angle": 0, + "content": "[46] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. In Int. Conf. Learn. Represent., 2021. 2, 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.127, + 0.471, + 0.866 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.127, + 0.893, + 0.165 + ], + "angle": 0, + "content": "[47] Yang Song, Conor Durkan, Iain Murray, and Stefano Ermon. Maximum likelihood training of score-based diffusion models. Adv. Neural Inform. Process. Syst., 34:1415-1428, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.166, + 0.893, + 0.204 + ], + "angle": 0, + "content": "[48] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. Adv. Neural Inform. Process. Syst., 32, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.205, + 0.893, + 0.243 + ], + "angle": 0, + "content": "[49] Yang Song and Stefano Ermon. Improved techniques for training score-based generative models. Adv. Neural Inform. Process. Syst., 33:12438-12448, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.245, + 0.893, + 0.295 + ], + "angle": 0, + "content": "[50] Yang Song, Jascha Sohl-Dickstein, Diederik P Kingma, Abhishek Kumar, Stefano Ermon, and Ben Poole. Score-based generative modeling through stochastic differential equations. Int. Conf. Learn. Represent., 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.296, + 0.893, + 0.334 + ], + "angle": 0, + "content": "[51] Arash Vahdat, Karsten Kreis, and Jan Kautz. Score-based generative modeling in latent space. In Adv. Neural Inform. Process. Syst., 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.334, + 0.893, + 0.386 + ], + "angle": 0, + "content": "[52] Aaron Van den Oord, Nal Kalchbrenner, Lasse Espeholt, Oriol Vinyals, Alex Graves, et al. Conditional image generation with pixelCNN decoders. Adv. Neural Inform. Process. Syst., 29, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.386, + 0.893, + 0.437 + ], + "angle": 0, + "content": "[53] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Adv. Neural Inform. Process. Syst., 30, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.438, + 0.893, + 0.478 + ], + "angle": 0, + "content": "[54] Yan Wu, Jeff Donahue, David Balduzzi, Karen Simonyan, and Timothy Lillicrap. Logan: Latent optimisation for generative adversarial networks. Int. Conf. Learn. Represent., 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.479, + 0.893, + 0.504 + ], + "angle": 0, + "content": "[55] Yuxin Wu and Kaiming He. Group normalization. In Eur. Conf. Comput. Vis., pages 3-19, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.505, + 0.893, + 0.554 + ], + "angle": 0, + "content": "[56] Xiulong Yang, Sheng-Min Shih, Yinlin Fu, Xiaoting Zhao, and Shihao Ji. Your vit is secretly a hybrid discriminative-generative diffusion model. arXiv preprint arXiv:2208.07791, 2022.3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.555, + 0.893, + 0.607 + ], + "angle": 0, + "content": "[57] Zhu Zhang, Jianxin Ma, Chang Zhou, Rui Men, Zhikang Li, Ming Ding, Jie Tang, Jingren Zhou, and Hongxia Yang. M6-ufc: Unifying multi-modal controls for conditional image synthesis. Adv. Neural Inform. Process. Syst., 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.608, + 0.893, + 0.647 + ], + "angle": 0, + "content": "[58] Jinghao Zhou, Chen Wei, Huiyu Wang, Wei Shen, Cihang Xie, Alan Yuille, and Tao Kong. ibot: Image bert pre-training with online tokenizer. Int. Conf. Learn. Represent., 2022. 3" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.127, + 0.893, + 0.647 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.465, + 0.888, + 0.505, + 0.899 + ], + "angle": 0, + "content": "23173" + } + ] +] \ No newline at end of file diff --git a/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/a412e570-59ba-43e9-aea5-2909edb799b1_origin.pdf b/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/a412e570-59ba-43e9-aea5-2909edb799b1_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..ada46ad2941a00f725d4528540a16000a46742b5 --- /dev/null +++ b/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/a412e570-59ba-43e9-aea5-2909edb799b1_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:8a2d83cffc073e385f0f8717acd0a28a09c7a89dd7e61c91ee2e2843a59c6fdb +size 941467 diff --git a/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/full.md b/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/full.md new file mode 100644 index 0000000000000000000000000000000000000000..0f940c5f98a7c524d74fe23b5a3b8a29b6d9dbb7 --- /dev/null +++ b/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/full.md @@ -0,0 +1,303 @@ +# Masked Diffusion Transformer is a Strong Image Synthesizer + +Shanghua Gao $^{1,2}$ * Pan Zhou $^{2\dagger}$ Ming-Ming Cheng $^{1\dagger}$ Shuicheng Yan $^{2}$ $^{1}$ Nankai University Sea AI Lab + +{shanghuagao, shuicheng.yan} $@$ gmail.com zhoupan@sea.com cmm@nankai.edu.cn + +# Abstract + +Despite its success in image synthesis, we observe that diffusion probabilistic models (DPMs) often lack contextual reasoning ability to learn the relations among object parts in an image, leading to a slow learning process. To solve this issue, we propose a Masked Diffusion Transformer (MDT) that introduces a mask latent modeling scheme to explicitly enhance the DPMs' ability to contextual relation learning among object semantic parts in an image. During training, MDT operates in the latent space to mask certain tokens. Then, an asymmetric masking diffusion transformer is designed to predict masked tokens from unmasked ones while maintaining the diffusion generation process. Our MDT can reconstruct the full information of an image from its incomplete contextual input, thus enabling it to learn the associated relations among image tokens. Experimental results show that MDT achieves superior image synthesis performance, e.g., a new SOTA FID score in the ImageNet data set, and has about $3 \times$ faster learning speed than the previous SOTA DiT. The source code is released at https://github.com/sail-sg/MDT. + +# 1. Introduction + +Diffusion probabilistic models (DPMs) [11, 38] have been at the forefront of recent advances in image-level generative models, often surpassing the previously state-of-the-art (SOTA) generative adversarial networks (GANs) [4, 17, 37, 54]. Additionally, DPMs have demonstrated their success in numerous other applications, including text-to-image generation [38] and speech generation [24]. DPMs adopt a time-inverted Stochastic Differential Equation (SDE) to gradually map a Gaussian noise into a sample by multiple time steps, with each step corresponding to a network evaluation. In practice, generating a sample is time-consuming due to the thousands of time steps required for the SDE to converge. To address this issue, various generation sampling strategies [21, 32, 41] have been proposed to accelerate the in + +![](images/f524cb6073718353db51791e480953b774e33c6eff34cb0e76e746fc172e8546.jpg) + +![](images/692b33b1879e9acc77fc48be6ad5d988561d14ba97d940bbb93f0ecac71efbd1.jpg) +Figure 1. Top: Visual examples of MDT/DiT [35]. Down: learning progress comparison between DiT and MDT w.r.t. training steps/time on $8 \times \mathrm{A}100$ GPUs. MDT has about $3 \times$ faster learning speed than DiT while achieving superior FID scores. + +![](images/1ac70bcc7407644542356c9d71aaefdcde249f163e75ee8359b872e0ca7b7063.jpg) + +ference speed. Nevertheless, improving the training speed of DPMs is less explored but highly desired. Training of DPMs also unavoidably requires a large number of time steps to ensure the convergence of SDEs, making it very computationally expensive, especially in this era where large-scale models [11,35] and data [9,14,44] are often used to improve generation performance. + +In this work, we first observe that DPMs often struggle to learn the associated relations among object parts in an image. This leads to its slow learning process during training. Specifically, as illustrated in Fig. 1, the classical DPM, DDPM [21] with DiT [35] as the backbone, has learned the shape of a dog at the $50\mathrm{k}$ -th training step, then learns its one eye and mouth until at the $200\mathrm{k}$ -th step while missing another eye. Also, the relative position of two ears is not very accurate, even at the $300\mathrm{k}$ -th step. This learning process reveals that DPMs fail to learn the associated relations + +among semantic parts and independently learn each semantic part. The reason behind this phenomenon is that DPMs maximize the log probability of real data by minimizing the per-pixel prediction loss, which ignores the associated relations among object parts in an image, thus resulting in their slow learning progress. + +Inspired by the above observation, we propose an effective Masked Diffusion Transformer (MDT) to improve the training efficiency of DPMs. MDT proposes a mask latent modeling scheme designed for transformer-based DPMs to explicitly enhance contextual learning ability and improve the associated relation learning among semantic parts in an image. Specifically, following [35, 38], MDT operates the diffusion process in the latent space to save computational costs. It masks certain image tokens and designs an asymmetric diffusion transformer structure to predict masked tokens from unmasked ones in a diffusion generation manner. To this end, the asymmetric structure contains an encoder, a side-interpolyter, and a decoder. The encoder and decoder modify the transformer block in DiT [35] by inserting global and local token position information to help predict masked tokens. The encoder only processes unmasked tokens during training handling all tokens during inference, as there are no masks. So to ensure the decoder always processes all tokens for training prediction or inference generation, a side-interpolyter implemented by a small network aims to predict masked tokens from encoder output during training, and it is removed during inference. + +With the masking latent modeling scheme, our MDT can reconstruct the full information of an image from its contextual incomplete input, learning the associated relations among semantic parts in an image. As shown in Fig. 1, MDT typically generates two eyes of the dog at almost the same training steps, indicating that it correctly learns the associated semantics of an image by utilizing the mask latent modeling scheme. In contrast, DiT [35] cannot easily synthesize a dog with the correct semantic part relations. This comparison shows MDT's superior relation modeling and faster learning ability over DiT. Experimental results demonstrate that MDT achieves superior performance on the image synthesis task, and set the new SOTA on class-conditional image synthesis on the ImageNet dataset, as shown in Fig. 2 and Tab. 2. MDT also enjoys about $3 \times$ faster learning progress during training than the SOTA DPMs, namely DiT, as demonstrated by Fig. 1 and Tab. 1. We hope our work can inspire more work on speeding up the diffusion training process with unified representation learning. + +The main contributions are summarised as follows: + +- By introducing an effective mask latent modeling scheme, we proposed a masked diffusion transformer method, which, for the first time, explicitly enhances the contextual learning ability of DPMs. + +![](images/54dd6a9f8830f3ff6229ac95d07991936d6dddf3890485b5816fc0dedd52c5b9.jpg) +Figure 2. Visualization of images generated by the MDT-XL/2. + +- Experiments show that our method better synthesis images while using much less training time than SOTA. + +# 2. Related works + +# 2.1. Diffusion Probabilistic models + +Diffusion probabilistic model (DPM) [11,21], also known as score-based model [48,49], is a competitive image synthesis approach. DPMs begin by using an evolving Stochastic Differential Equation (SDE) to gradually add Gaussian noise into real data, transforming a complex data distribution into a Gaussian distribution. Then, it adopts a time-inverted SDE to map a Gaussian noise gradually into a sample by multiple steps. At each sampling time step, a network is utilized to generate the sample along the gradient of the log probability, also known as the score function [50]. The iterative nature of diffusion models can result in high training and inference costs. Efficient sampling strategies [21,23,32,41,46], latent space diffusion [38,51], and multi-resolution cascaded generation [22] have been proposed to reduce the inference cost. Additionally, some training schemes [2, 12] are introduced to improve the diffusion model training, e.g., approximate maximum likelihood training [28, 34, 47], and training loss weighting [26, 27]. We identify the lack of contextual modeling ability in diffusion models. To address this, we propose the mask latent modeling scheme to enhance the contextual representation of diffusion models, which is orthogonal to existing diffusion training schemes. + +# 2.2. Networks for Diffusion Models + +The UNet-like [39] network, enhanced by spatial selfattention [42,52] and group normalization [55] is firstly used for diffusion models [21]. Several design improvements, e.g., adding more attention heads [18], BigGAN [4] residual block, and adaptive group normalization, are proposed in [11] to further enhance the generation ability of the UNet. + +Recently, due to the broad applicability of transformer networks, several works have attempted to utilize the vision transformer (ViT) structure for diffusion models [1,35,56]. GenViT [56] demonstrates that ViT is capable of image generation but has inferior performance compared to UNet. U-ViT [1] improves ViT by adding long-skip connections and convolutional layers, achieving competitive performance with that of UNet. DiT [35] verifies the scaling ability of ViT on large model sizes and feature resolutions. Our MDT is orthogonal to these diffusion networks as it focuses on contextual representation learning. Moreover, the position-aware designs in MDT reveal that the mask latent modeling scheme benefits from a stronger diffusion network. We will explore further to release the potential of these networks with MDT. + +# 2.3. Mask Modeling + +Mask modeling has been proven to be effective in both recognition learning [8, 10, 15, 19] and generative modeling [7, 36]. In the natural language processing (NLP) field, mask modeling was first introduced to enable representation pretraining [10, 36] and language generation [5, 25]. Subsequently, it also proved feasible for vision recognition [3] and generation [7, 16, 57] tasks. In vision recognition, pretraining schemes that utilize mask modeling enable good representation quality [58], scalability [19] and faster convergence [15]. In generative modeling, following the bidirectional generative modeling in NLP, MaskGIT [7] and MUSE [6] use the masked generative transformer to predict randomly masked image tokens for image generation. Similarly, VQ-Diffusion [16] presents a mask-replace diffusion strategy to generate images. In contrast, our MDT aims to enhance the contextual representation of the denoising diffusion transformer [35] with mask latent modeling. This preserves the detail refinement ability of denoising diffusion models by maintaining the diffusion process during inference. To ensure that the mask latent modeling in MDT focuses on representation learning instead of reconstruction, we propose an asymmetrical structure in mask modeling training. As an extra benefit, it enables lower training costs than masked generative models because it skips the masked patches in training instead of replacing masked input patches with a mask token. + +# 3. Masked Diffusion Transformer + +Revisit Diffusion Probabilistic Model. For diffusion probabilistic models [11, 45], such as DDPM [21] and DDIM [46], training involves a forward noising process and a reverse denoising process. In the forward noising process, Gaussian noise $\epsilon \sim \mathcal{N}(0,\mathbf{I})$ is gradually added to the real sample $x_0$ via a discrete SDE formulation [46]. If the time step $t$ is large, $x_{t}$ would be a Gaussian noise. Similarly, the reverse denoising process is a discrete SDE that grad + +![](images/f6cbb90df5f4411a0741afb1b35c1282697025c33bd71cb9d75fbf0a09ac5078.jpg) +Figure 3. The overall framework of Masked Diffusion Transformer (MDT). Solid/dotted lines indicate each time step's training/inference process. Masking and side-interpolater are only used during training and are removed during inference. + +ually maps a Gaussian noise into a sample. At each time step, given $x_{t}$ , it predicts the next reverse step $p_{\theta}(x_{t - 1}|x_t)$ via a network. Following [34, 35], the network is trained by optimizing the variational lower-bound $L_{\mathrm{vlb}}$ of the log-likelihood $p_{\theta}(x_0)$ [45]. During inference, one can sample a Gaussian noise and then gradually reverses to a sample $x_0$ . Same as [34, 35], we train the diffusion model conditioned with class label $c$ , i.e. $p_{\theta}(x_{t - 1}|x_t,c)$ . By default, we use class-conditioned image generation in our experiments. + +# 3.1. Overview + +As shown in Fig. 1, DPMs with DiT backbone exhibit slow training convergence due to the slowly learning of the associated relations among semantic parts in an image. To relieve this issue, we propose Masked Diffusion Transformer (MDT), which introduces a mask latent modeling scheme to enhance contextual learning ability explicitly. To this end, as depicted in Fig. 3, MDT consists of 1) a latent masking operation to mask the input image in the latent space, and 2) an asymmetric masking diffusion transformer structure that performs vanilla diffusion process as DPMs, but with masked input. To reduce computational costs, MDT follows LatentDiffusion [38] to perform generative learning in the latent space instead of raw pixel space. + +In the training phase, MDT first encodes an image into a latent space with a pre-trained VAE encoder [38]. Then, MDT adds Gaussian noise into the image latent embedding. The latent masking operation in MDT then patchifies the resulting noisy latent embedding into a sequence of tokens, and masks certain tokens. The remaining unmasked tokens are fed into the asymmetric masking diffusion transformer, as shown in Fig. 4(a), which contains an encoder, a side-interpolater, and a decoder to predict the masked tokens from the unmasked ones. During inference, MDT replaces the side-interpolater with additional position embedding. MDT takes the latent embedding of a Gaussian noise as input to + +generate the denoised latent embedding, which is then passed to a pre-trained VAE decoder [38] for image generation. + +The above masking latent modeling scheme in the training phase forces the diffusion model to reconstruct the full information of an image from its contextual incomplete input. Thus, the model is encouraged to learn the relations among image latent tokens, particularly the associated relations among semantic parts in an image. For example, as illustrated in Fig. 3, the model should first understand the correct associated relations among small image parts (tokens) of the dog image. Then, it should generate the masked "eye" tokens using other unmasked tokens as contextual information. Furthermore, Fig. 1 shows that MDT often learns to generate the associated semantics of an image at nearly the same pace, such as the generation of the dog's two eyes (two ears) at almost the same training step. While DiT [35] (DDPM with transformer backbone) learns to generate one eye (one ear) initially and then learns to generate another eye (ear) after roughly 100k training steps. This demonstrates the superior learning ability of MDT over DiT in terms of the associated relation learning of image semantics. + +In the following parts, we will introduce the two key components of MDT, 1) a latent masking operation, and 2) an asymmetric masking diffusion transformer structure. + +# 3.2. Latent Masking + +Following the Latent diffusion model (LDM) [38], MDT performs generation learning in the latent space instead of raw pixel space to reduce computational costs. In the following, we briefly recall LDM and then introduce our latent masking operation on the latent input. + +Latent diffusion model (LDM). LDM employs a pretrained VAE encoder $\mathbf{E}$ to encode an image $v\in \mathbb{R}^{3\times H\times W}$ to a latent embedding $z = \mathbf{E}(v)\in \mathbb{R}^{c\times h\times w}$ . It gradually adds noise to $z$ in the forward process and then denoises to predict $z$ in the reverse process. Finally, LDM uses a pre-trained VAE decoder $\mathbf{D}$ to decode $z$ into a high-resolution image $v = \mathbf{D}(z)$ . Both the VAE encoder and decoder are fixed during training and inference. Since $h$ and $w$ are smaller than $H$ and $W$ , performing the diffusion process in the low-resolution latent space is more efficient than pixel space. + +Latent masking operation. We first add Gaussian noise to an image's latent embedding $z$ during training. Then following [35], we divide the noisy embedding $z$ into a sequence of $p \times p$ -sized tokens and concatenate them to a matrix $u \in \mathbb{R}^{d \times N}$ , where $d$ is the channel number and $N$ is the number of tokens. Next, we randomly mask tokens with a ratio $\rho$ and concatenate the remaining tokens as $\hat{u} \in \mathbb{R}^{d \times \hat{N}}$ , where $\hat{N} = \rho N$ . Accordingly, we can create a binary mask $M \in \mathbb{R}^N$ in which one (zero) denotes the masked (unmasked) tokens. Finally, we feed the tokens $\hat{u}$ + +![](images/6e8cfbab54ad0416c1621b736a568ae60e21daec418f45fba591a96fa2584553.jpg) + +![](images/f4cb86fc985d4b48df6ca0e48d16eee101b1e0b49205d3e21e8cb54367a9b812.jpg) + +![](images/867e8bee79ceb5d3bcd61cf25a7922e807753d9aba58eaaa49a9dba627ba7462.jpg) +Figure 4. The asymmetric masking diffusion transformer structure in MDT. We modify the DiT [35] by adding a side-interpolater, local relative positional bias, and learnable global position embeddings. The conditional scheme is omitted for simplicity. + +into our diffusion model for processing. We only use tokens $\hat{u}$ for two reasons. 1) The model should focus on learning semantics instead of predicting the masked tokens. As shown in Sec. 4.3, it achieves better performance than replacing the masked tokens with a learnable mask token and then processing all tokens like [3, 6, 7]; 2) It saves the training cost compared to processing all $N$ tokens. + +# 3.3. Asymmetric Masking Diffusion Transformer + +We introduce our asymmetric masking diffusion transformer for joint training of mask latent modeling and diffusion process. As shown in Fig. 4(a), it consists of three components: an encoder, a side-interpolyater, and a decoder, each of which is described in detail below. + +Position-aware encoder and decoder. In MDT, predicting the masked latent tokens from the unmasked tokens requires the position relations of all tokens. To enhance the position information in the model, we propose a positional-aware encoder and decoder that facilitate the learning of the masked latent tokens. Specifically, the encoder and decoder tailor the standard DiT block via adding two types of token position + +information containing $N_{1}$ and $N_{2}$ blocks, as illustrated in Fig. 4(a). + +Firstly, the encoder adds the conventional learnable global position embedding into the noisy latent embedding input. Similarly, the decoder introduces the learnable position embedding into its input but with different training and inference phase approaches. The side-interpolater already uses the learnable global position embedding introduced below during training. During inference, since the side interpolater is discarded (see below), the decoder explicitly adds the position embedding into its input to enhance positional information. + +Secondly, as depicted in Fig. 4(b), the encoder and decoder add a local relative positional bias [30] to each head in each block when computing the attention score of the self-attention [53]: + +$$ +\operatorname {A t t e n t i o n} (Q, K, V) = \operatorname {S o f t m a x} \left(\frac {Q K ^ {\top}}{\sqrt {d _ {k}}} + B _ {r}\right) V, +$$ + +where $Q$ , $K$ , and $V$ , respectively denote the query, key, and value in the self-attention module, $d_k$ is the dimension of the key, and $B_r \in \mathbb{R}^{N \times N}$ is the relative positional bias. $B_r$ is selected by the relative positional difference between the $i$ -th position and other positions, which is updated during training. The local relative positional bias helps to capture the relative relations among tokens, facilitating the masking of latent modeling. + +The encoder takes the unmasked noisy latent embedding provided by our latent masking operation and feeds its output into the side-interpolater/decoder during training/inference. For the decoder, its input is the output of the side-interpolater for training or the combination of the encoder output and the learnable position embedding for inference. During training, the encoder and decoder, respectively, handle unmasked tokens and full tokens. Thus, we name our model the "asymmetric" model. + +Side-interpolater. As shown in Fig. 3, during training, for efficiency and better performance, the encoder only processes the unmasked tokens $\hat{u}$ . While in the inference phase, the encoder handles all tokens $u$ due to the lack of masks. This means that there is a big difference in the encoder output (i.e., decoder input) during training and inference, at least in terms of token number. To ensure the decoder always processes all tokens for training prediction or inference generation, a side-interpolyter implemented by a small network aims to predict masked tokens from encoder output during training and would be removed during inference. + +In the training phase, the encoder processes the unmasked tokens to obtain its output token embedding $\hat{q} \in \mathbb{R}^{d \times \hat{N}}$ . Then, as shown in Fig. 4(c), the side-interpolater first fills the masked positions, indicated by the mask $M$ defined in Sec. 3.2, by a shared learnable mask token, and also adds + +a learnable positional embedding to obtain an embedding $q \in \mathbb{R}^{d \times N}$ . Next, we use a basic encoder block to process $q$ to predict an interpolated embedding $\hat{k}$ . The $\hat{k}$ tokens denote the predicted tokens. Finally, we use a masked shortcut connection to combine prediction $\hat{k}$ and $q$ as $k = M \cdot q + (1 - M) \cdot \hat{k}$ . In summary, for masked tokens, we use the prediction by side-interpolyter. For unmasked tokens, we still adopt the corresponding tokens in $q$ . This can 1) boost the consistency between training and inference phases, 2) eliminates the mask-reconstruction process in the decoder. + +Since there are no masks during inference, the side-interpolater is replaced by a position embedding operation, which adds the learnable position embeddings of the side-interpolater, learned during training. This ensures the decoder always processes all tokens and uses the same learnable position embeddings for training prediction or inference generation, thus having better image generation performance. + +# 3.4. Training + +During training, we feed both full latent embedding $u$ and the masked latent embedding $\hat{u}$ to the diffusion model. We observe that only using masked latent embedding makes the model focus too much on masked region reconstruction, while ignoring the diffusion training. Full/masked latent inputs are independently sent to the network, and the training objectives optimize the variational lower-bound, as in [34, 35]. Due to the asymmetrical masking structure, the extra costs for using masked latent embedding are small. This is also demonstrated by Fig. 1, which shows that MDT still achieves about $3 \times$ faster learning progress than previous SOTA DiT in total training hours. + +# 4. Experiments + +# 4.1. Implementation + +We give the implementation details of MDT, including model architecture, training details, and evaluation metrics. + +Model architecture. We follow DiT [35] to set the total block number (i.e., $N_{1} + N_{2}$ ), token number, and channel numbers of the diffusion transformer of MDT. As DiT reveals stronger synthesis performance when using a smaller patch size, we also use a patch size $p = 2$ by default, denoted by MDT-/2. Moreover, We also follow DiT's parameters to design MDT for getting its small-, base-, and xlarge-sized model, denoted by MDT-S/B/XL. Same as LatentDiffusion [38] and DiT, MDT adopts the fixed $\mathrm{VAE}^{1}$ provided by the Stable Diffusion to encode/decode the image/latent tokens by default. The VAE encoder has a downsampling ratio of $1 / 8$ , and a feature channel dimension of 4, e.g., an image + +
MethodImage Res.Training Steps (k)FID-50K↓
DiT-S/2256×25640068.40
MDT-S/2256×25630057.01
MDT-S/2256×25640053.46
MDT-S/2256×256200044.14
MDT-S/2256×256350041.37
DiT-B/2256×25640043.47
MDT-B/2256×25640034.33
MDT-B/2256×256350020.45
DiT-XL/2256×25640019.47
DiT-XL/2256×256235210.67
DiT-XL/2256×25670009.62
MDT-XL/2256×25640016.42
MDT-XL/2256×25613009.60
MDT-XL/2256×25635006.65
+ +of size $256 \times 256 \times 3$ is encoded into a latent embedding of size $32 \times 32 \times 4$ . + +Training details. Following [35], all models are trained by AdamW [31] optimizer of 3e-4 learning rate, 256 batch size, and without weight decay on ImageNet [9] with an image resolution of $256 \times 256$ . We set the mask ratio as 0.3 and $N_{2} = 2$ . Following the training settings in DiT, we set the maximum step in training to 1000 and use the linear variance schedule with a range from $10^{-4}$ to $2 \times 10^{-2}$ . Other settings are also aligned with DiT. + +Evaluation. We evaluate models with commonly used metrics, i.e. Frechet Inception Distance (FID) [20], sFID [33], Inception Score (IS) [40], Precision and Recall [29]. The FID is used as the major metric as it measures both diversity and fidelity. sFID improves upon FID by evaluating at the spatial level. As a complement, IS and Precision are used for measuring fidelity, and Recall is used to measure diversity. For fair comparisons, we follow [35] to use the TensorFlow evaluation suite from ADM [11] and report FID-50K with 250 DDPM sampling steps. Unless specified otherwise, we report the FID scores without the classifier-free guidance [23]. + +# 4.2. Comparison Results + +Performance comparison. Tab. 1 compares our MDT with the SOTA DiT under different model sizes. It is evident that MDT achieves higher FID scores for all model scales with fewer training costs. The parameters and inference cost of MDTs are similar to DiT, since the extra modules in MDT are negligible as introduced in Sec. 3.1. For small models, + +Table 1. Comparison between DiT [35] and MDT under different model sizes and training steps on ImageNet $256\times 256$ . DiT results are obtained from DiT reported results. + +
MethodCost(ITer×BS)FID↓sFID↓IS↑Prec.↑Rec.↑
DCTrans. [33]-36.51--0.360.67
VQVAE-2 [37]-31.11--0.360.57
VQGAN [13]-15.7878.3---
BigGAN-deep [4]-6.957.36171.40.870.28
StyleGAN [43]-2.304.02265.120.780.53
Impr. DDPM [34]-12.26--0.700.62
MaskGIT [7]1387k×2566.18-182.10.800.51
CDM [22]-4.88-158.71--
ADM [11]1980k×25610.946.02100.980.690.63
LDM-8 [38]4800k×6415.51-79.030.650.63
LDM-4178k×120010.56-103.490.710.62
DiT-XL/2 [35]7000k×2569.626.85121.500.670.67
MDT2500k×2567.414.95121.220.720.64
MDT3500k×2566.464.92131.700.720.63
MDT6500k×2566.235.23143.020.710.65
ADM-G [11]1980k×2564.595.25186.700.820.52
ADM-G, U1980k×2563.946.14215.840.830.53
LDM-8-G [38]4800k×647.76-209.520.840.35
LDM-4-G178k×12003.60-247.670.870.48
U-ViT-G [1]300k×10243.40----
DiT-XL/2-G [35]7000k×2562.274.60278.240.830.57
MDT-G2500k×2562.154.52249.270.820.58
MDT-G3500k×2562.024.46263.770.820.60
MDT-G6500k×2561.794.57283.010.810.61
+ +Table 2. Comparison with existing methods on class-conditional image generation with the ImageNet $256 \times 256$ dataset. -G denotes the results with classifier-free guidance [23]. Results of MDT-XL/2 model are given for comparison. Compared results are obtained from their papers. + +MDT-S/2 trained with 300k steps outperforms the DiT-S/2 trained with 400k steps by a large margin on FID (57.01 vs. 68.40). More importantly, MDT-S/2 trained with 2000k steps achieves similar performance with a larger model DiT-B/2 trained with a similar computational budget. For the largest model, MDT-XL/2 trained with 1300k steps outperforms DiT-XL/2 trained with 7000k steps on FID (9.60 vs. 9.62), achieving about $5 \times$ faster training progress. + +We also compare the class-conditional image generation performance of MDT with existing methods in Tab. 2. To make fair comparisons with DiT, we also use the EMA weights of VAE decoder in this table. Under class-conditional settings, MDT with half training iterations outperforms DiT by a large margin, e.g., 6.83 vs 9.62 in FID. Following previous works [1, 11, 35, 38], we utilize an improved classifier-free guidance [23] with a power-cosine weight scaling to trade off between precision and recall during class-conditional sampling. MDT achieves superior performance over previous SOTA DiT and other methods with the FID score of 1.81, setting a new SOTA for class-conditional image generation. Similar to DiT, we never + +
Mask RatioFID↓sFID↓IS↑Precision↑Recall↑
0.151.6010.2326.650.440.60
0.251.4410.0926.750.440.58
0.350.2610.0827.610.450.60
0.450.8810.2127.440.450.60
0.551.579.9227.140.440.60
0.653.2010.3626.550.440.61
0.752.9010.0326.510.440.61
0.853.7310.1525.550.430.61
+ +Table 3. Effect of different masking ratios. MDT-S/2 trained with 600k iterations. + +
Decoder pos.FID↓sFID↓IS↑Precision↑Recall↑
Last051.059.9727.310.440.60
Last150.969.9027.630.450.60
Last250.2610.0827.610.450.60
Last451.6710.1226.910.450.60
Last652.6410.3626.460.440.60
+ +Table 4. Effect of position of side-interpolater. MDT-S/2 models contain 12 blocks and are trained with 600k iterations. + +observe the model has saturated FID scores when continuing training. + +Convergence speed. Fig. 1 compares the performance of the DiT/S-2 baseline and MDT/S-2 under different training steps and training time on $8 \times \mathrm{A}100$ GPUs. Because of the stronger contextual learning ability, MDT achieves better performance with faster generation learning speed. MDT enjoys about $3 \times$ faster learning speed in terms of both training steps and training time. For example, MDT-S/2 trained with about 33 hours (400k steps) achieves superior performance than DiT-S/2 trained with about 100 hours (1500k steps). This reveals that contextual learning is vital for faster generation learning of diffusion models. + +# 4.3. Ablation + +In this part, we conduct ablation to verify the designs in MDT. We report the results of MDT-S/2 model and use FID-50k as the evaluation metric unless otherwise stated. + +Masking ratio. The masking ratio determines the number of input patches that can be processed during training. We give the comparison of using different masking ratios in Tab. 3. The best masking ratio for MDT-S/2 is $30\%$ , which is quite different from the masking ratio used for recognition models, e.g. $75\%$ masking ratio in MAE [19]. We assume that the image generation requires learning more details from more patches for high-quality synthesis, while recognition models only need the most essential patches to infer semantics. + +Side-interpolater position. To meet the high-quality image generation requirements of the diffusion model, the side-interpolater is placed in the middle of the network instead of the end of the network in recognition models [3, 19]. Tab. 4, presents the comparison of placing the side-interpolater at different positions of the MDT-S model with 12 blocks. The results show that placing the side-interpolater before the last two blocks achieves the best FID score, whereas placing it at the end of the network like recognition models impairs the performance. Placing the side-interpolater at the early stages of the network also harm the performance, indicating the mask latent modeling is beneficial to most stages in the diffusion models. + +Asymmetric vs. Symmetric architecture in masking. Unlike the masked generation works [6, 7], e.g., MaskGIT, that utilize the masking scheme to generate images, MDT focuses on improving diffusion models with contextual learning ability via the masking latent modeling. Therefore, we use an asymmetric architecture to only process the unmasked tokens in the diffusion model encoder. We compare the asymmetric architecture in MDT and the symmetrical architecture [7] that processes full input with masked tokens replaced by a learnable mask token. As shown in Tab. 5a, the asymmetric architecture in MDT has an FID of 50.26, outperforming the FID of 51.56 achieved by the symmetric architecture. The asymmetric architecture further reduces the training cost and allows the diffusion model to focus on learning contextual information instead of reconstructing masked tokens. + +Effect of side-interpolater. The side-interpolater in MDT predicts the masked tokens, allowing the diffusion model to learn more semantics and maintain consistency in decoder inputs during training and inference. We compare the performance with/without the side-interpolater in Tab. 5b, and observe a gain of 1.34 in FID when using the side-interpolater, proving its effectiveness. + +Masked shortcut in side-interpolater. The masked shortcut ensures that the side-interpolater only predicts the masked tokens from unmasked ones. Tab. 5c shows that using the masked shortcut enhances the FID from 50.91 to 50.26, indicating that restricting side-interpolater to only predict masked tokens helps the diffusion model achieve stronger performance. + +Full and masked latent tokens. In MDT, both the full and masked latent embeddings are fed into the diffusion model during training. In comparison, we give the results trained by only using full/masked latent embeddings as shown in Tab. 5d, where the computational cost is aligned for + +
Asymmetric stru.FID-50k↓
×51.56
✓50.26
+ +(a) Effect of asymmetric masking structure. + +
Side-interpolaterFID-50k↓
×51.60
✓50.26
+ +(b) Effect of side-interpolater. + +
Masked shortcutFID-50k↓
×50.91
✓50.26
+ +(c) Effect of masked shortcut. + +
Latent typeFID-50k↓
Full+Masked50.26
Full52.30
Masked76.63
+ +(d) Using full/masked latent under aligned cost. + +
Sup. partsFID-50k↓
All50.26
Masked58.35
+ +(e) Supervision on token parts. + +
NumberFID-50k↓
150.26
251.77
351.96
+ +(f) Number of blocks in side-interpolator. + +
IS Pos. embed.FID-50k↓
×51.58
✓50.26
+ +(g) Effect of positional embeddings in SI. + +
Learnable pos.FID-50k↓
×50.80
✓50.26
+ +(h) Effect of learnable positional embeddings. + +
Relative pos. biasFID-50k↓
×53.56
✓50.26
+ +(i) Effect of relative positional bias. + +Table 5. Ablation study on MDT-S/2. Models are trained for 600k iterations. + +fair comparisons. Trained with both full and masked latent leads to clear gain over two competitors. While using only the masked latent embeddings results in slow convergence, which we attribute to the training/inference inconsistency as the inference in MDT is a diffusion process instead of the masked reconstruction process. + +Loss on all tokens. By default, we calculate the loss on both masked and unmasked latent embeddings. In comparison, mask modeling for recognition models commonly calculates loss on masked tokens [3, 19]. Tab. 5e shows that calculating the loss on all tokens is much better than on masked tokens. We assume that this is because generative models require stronger consistency among patches than recognition models do, since details are vital for high-quality image synthesis. + +Block number in side-interpolater. We compare the performance of different numbers of blocks in the side-interpolater in Tab. 5f. The default setting of 1 block achieves the best performance, and the FID worsens with an increase in block number. This result is consistent with our motivation that side-interpolater should not learn too much information other than interpolating the masked representations. + +Positional-aware enhancement. To further release the potential of mask latent modeling, we enhance the DiT baseline with stronger positional awareness ability, i.e. learnable positional embeddings and the relative positional bias in basic blocks. Tab. 5g shows the positional embeddings in side-interpolator improves the FID from 51.58 to 50.26, indicating the positional embedding is vital for the side-interpolator. + +Also, enables the training of positional embeddings brings the gain in FID as revealed in Tab. 5h. In Tab. 5i, the relative positional bias in the basic blocks significantly improves the FID from 53.56 to 50.26, showing the relative positional modeling ability is essential for diffusion models to obtain the contextual representation ability and generate high-quality images. Therefore, the positional awareness ability in diffusion model structure is required to accompany the masked latent modeling, playing a key role in improving performance. + +# 5. Conclusion + +This work proposes a masked diffusion transformer to enhance the contextual representation and improve the relation learning among image semantics for DPMs. We introduce an effective mask latent modeling scheme into DPMs and also accordingly designs an asymmetric masking diffusion transformer structure. Experiments show that our masked diffusion transformer enjoys higher performance on image synthesis and largely improves the learning progress during training, achieving the new SOTA for image synthesis on the ImageNet dataset. We hope our initial exploration of contextual learning for generative modeling can facilitate more work on unifying the representation learning for recognition and generative models. + +# Acknowledgement. + +This research was supported by the NSFC (NO. 62225604) and the Fundamental Research Funds for the Central Universities (Nankai University, 070-63233089). The Supercomputing Center of Nankai University supports computation. + +# References + +[1] Fan Bao, Chongxuan Li, Yue Cao, and Jun Zhu. All are worth words: a vit backbone for score-based diffusion models. arXiv preprint arXiv:2209.12152, 2022. 3, 6 +[2] Fan Bao, Chongxuan Li, Jiacheng Sun, Jun Zhu, and Bo Zhang. Estimating the optimal covariance with imperfect mean in diffusion probabilistic models. In Int. Mach. Learn., 2022. 2 +[3] Hangbo Bao, Li Dong, and Furu Wei. Beit: Bert pre-training of image transformers. Int. Conf. Learn. Represent., 2022. 3, 4, 7, 8 +[4] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. Int. Conf. Learn. Represent., 2019. 1, 2, 6 +[5] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, et al. Language models are few-shot learners. Adv. Neural Inform. Process. Syst., 33:1877-1901, 2020. 3 +[6] Huiwen Chang, Han Zhang, Jarred Barber, AJ Maschinot, Jose Lezama, Lu Jiang, Ming-Hsuan Yang, Kevin Murphy, William T Freeman, Michael Rubinstein, et al. Muse: Text-to-image generation via masked generative transformers. arXiv preprint arXiv:2301.00704, 2023. 3, 4, 7 +[7] Huiwen Chang, Han Zhang, Lu Jiang, Ce Liu, and William T Freeman. Maskgit: Masked generative image transformer. In IEEE Conf. Comput. Vis. Pattern Recog., pages 11315-11325, 2022. 3, 4, 6, 7 +[8] Gong Cheng, Ruimin Li, Chunbo Lang, and Junwei Han. Task-wise attention guided part complementary learning for few-shot image classification. Science China Information Sciences, 64:1-14, 2021. 3 +[9] J. Deng, W. Dong, R. Socher, L.-J. Li, K. Li, and L. Fei-Fei. Imagenet: A large-scale hierarchical image database. In IEEE Conf. Comput. Vis. Pattern Recog., 2009. 1, 6 +[10] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. NAACL, 2019. 3 +[11] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Adv. Neural Inform. Process. Syst., 34:8780-8794, 2021. 1, 2, 3, 6 +[12] Tim Dockhorn, Arash Vahdat, and Karsten Kreis. Score-based generative modeling with critically-damped Langevin diffusion. In Int. Conf. Learn. Represent., 2022. 2 +[13] Patrick Esser, Robin Rombach, and Bjorn Ommer. Taming transformers for high-resolution image synthesis. In IEEE Conf. Comput. Vis. Pattern Recog., pages 12873-12883, 2021. 6 +[14] Shanghua Gao, Zhong-Yu Li, Ming-Hsuan Yang, Ming-Ming Cheng, Junwei Han, and Philip Torr. Large-scale unsupervised semantic segmentation. IEEE Trans. Pattern Anal. Mach. Intell., 2022. 1 +[15] Shanghua Gao, Pan Zhou, Ming-Ming Cheng, and Shuicheng Yan. Towards sustainable self-supervised learning. arXiv preprint arXiv:2210.11016, 2022. 3 + +[16] Shuyang Gu, Dong Chen, Jianmin Bao, Fang Wen, Bo Zhang, Dongdong Chen, Lu Yuan, and Baining Guo. Vector quantized diffusion model for text-to-image synthesis. In IEEE Conf. Comput. Vis. Pattern Recog., pages 10696-10706, 2022. 3 +[17] Yuchao Gu, Xintao Wang, Yixiao Ge, Ying Shan, Xiaohu Qie, and Mike Zheng Shou. Rethinking the objectives of vector-quantized tokenizers for image synthesis. arXiv preprint arXiv:2212.03185, 2022. 1 +[18] Meng-Hao Guo, Tian-Xing Xu, Jiang-Jiang Liu, Zheng-Ning Liu, Peng-Tao Jiang, Tai-Jiang Mu, Song-Hai Zhang, Ralph R. Martin, Ming-Ming Cheng, and Shi-Min Hu. Attention mechanisms in computer vision: A survey. Computational Visual Media, 8(3):331-368, 2022. 2 +[19] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollar, and Ross Girshick. Masked autoencoders are scalable vision learners. In IEEE Conf. Comput. Vis. Pattern Recog., pages 16000-16009, 2022. 3, 7, 8 +[20] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Adv. Neural Inform. Process. Syst., 30, 2017. 6 +[21] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Adv. Neural Inform. Process. Syst., 33:6840-6851, 2020. 1, 2, 3 +[22] Jonathan Ho, Chitwan Sahara, William Chan, David J Fleet, Mohammad Norouzi, and Tim Salimans. Cascaded diffusion models for high fidelity image generation. J. Mach. Learn. Res., 23(47):1-33, 2022. 2, 6 +[23] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. NeurIPS Workshop, 2021. 2, 6 +[24] Myeonghun Jeong, Hyeongju Kim, Sung Jun Cheon, Byoung Jin Choi, and Nam Soo Kim. Diff-tps: A denoising diffusion model for text-to-speech. In INTERSPEECH, 2021. 1 +[25] Ge-Peng Ji, Mingchen Zhuge, Dehong Gao, Deng-Ping Fan, Christos Sakaridis, and Luc Van Gool. Masked vision-language transformer in fashion. Machine Intelligence Research, 20(3):421-434, 2023. 3 +[26] Tero Karras, Miika Aittala, Timo Aila, and Samuli Laine. Elucidating the design space of diffusion-based generative models. In Adv. Neural Inform. Process. Syst., 2022. 2 +[27] Dongjun Kim, Seungjae Shin, Kyungwoo Song, Wanmo Kang, and Il-Chul Moon. Soft truncation: A universal training technique of score-based diffusion model for high precision score estimation. In Int. Mach. Learn., 2022. 2 +[28] Diederik Kingma, Tim Salimans, Ben Poole, and Jonathan Ho. Variational diffusion models. Adv. Neural Inform. Process. Syst., 34:21696-21707, 2021. 2 +[29] Tuomas Kynkänniemi, Tero Karras, Samuli Laine, Jaakko Lehtinen, and Timo Aila. Improved precision and recall metric for assessing generative models. Adv. Neural Inform. Process. Syst., 32, 2019. 6 +[30] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Int. Conf. Comput. Vis., pages 10012-10022, 2021. 5 + +[31] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. Int. Conf. Learn. Represent., 2019. 6 +[32] Cheng Lu, Yuhao Zhou, Fan Bao, Jianfei Chen, Chongxuan Li, and Jun Zhu. Dpm-solver: A fast ode solver for diffusion probabilistic model sampling in around 10 steps. Adv. Neural Inform. Process. Syst., 2022. 1, 2 +[33] Charlie Nash, Jacob Menick, Sander Dieleman, and Peter W Battaglia. Generating images with sparse representations. Int. Mach. Learn., 2021. 6 +[34] Alexander Quinn Nichol and Prafulla Dhariwal. Improved denoising diffusion probabilistic models. In Int. Mach. Learn., pages 8162-8171. PMLR, 2021. 2, 3, 5, 6 +[35] William Peebles and Saining Xie. Scalable diffusion models with transformers. arXiv preprint arXiv:2212.09748, 2022. 1, 2, 3, 4, 5, 6 +[36] Alec Radford, Karthik Narasimhan, Tim Salimans, Ilya Sutskever, et al. Improving language understanding by generative pre-training, 2018. 3 +[37] Ali Razavi, Aaron Van den Oord, and Oriol Vinyals. Generating diverse high-fidelity images with vq-vae-2. Adv. Neural Inform. Process. Syst., 32, 2019. 1, 6 +[38] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In IEEE Conf. Comput. Vis. Pattern Recog., pages 10684-10695, 2022. 1, 2, 3, 4, 5, 6 +[39] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In Int. Conf. Med Image Comput Comput Assist Interv., pages 234-241. Springer, 2015. 2 +[40] Tim Salimans, Ian Goodfellow, Wojciech Zaremba, Vicki Cheung, Alec Radford, and Xi Chen. Improved techniques for training gans. Adv. Neural Inform. Process. Syst., 29, 2016. 6 +[41] Tim Salimans and Jonathan Ho. Progressive distillation for fast sampling of diffusion models. Int. Conf. Learn. Represent., 2022. 1, 2 +[42] Tim Salimans, Andrej Karpathy, Xi Chen, and Diederik P Kingma. PixelCNN++: Improving the pixelCNN with discretized logistic mixture likelihood and other modifications. In Int. Conf. Learn. Represent., 2017. 2 +[43] Axel Sauer, Katja Schwarz, and Andreas Geiger. Stylegan-xl: Scaling stylegan to large diverse datasets. In ACM SIGGRAPH 2022 conference proceedings, pages 1-10, 2022. 6 +[44] Christoph Schuhmann, Romain Beaumont, Richard Vencu, Cade Gordon, Ross Wightman, Mehdi Cherti, Theo Coombes, Aarush Katta, Clayton Mullis, Mitchell Wortsman, et al. Laion-5b: An open large-scale dataset for training next generation image-text models. Adv. Neural Inform. Process. Syst., 2022. 1 +[45] Jascha Sohl-Dickstein, Eric Weiss, Niru Maheswaranathan, and Surya Ganguli. Deep unsupervised learning using nonequilibrium thermodynamics. In Int. Mach. Learn., pages 2256-2265. PMLR, 2015. 3 +[46] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. In Int. Conf. Learn. Represent., 2021. 2, 3 + +[47] Yang Song, Conor Durkan, Iain Murray, and Stefano Ermon. Maximum likelihood training of score-based diffusion models. Adv. Neural Inform. Process. Syst., 34:1415-1428, 2021. 2 +[48] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. Adv. Neural Inform. Process. Syst., 32, 2019. 2 +[49] Yang Song and Stefano Ermon. Improved techniques for training score-based generative models. Adv. Neural Inform. Process. Syst., 33:12438-12448, 2020. 2 +[50] Yang Song, Jascha Sohl-Dickstein, Diederik P Kingma, Abhishek Kumar, Stefano Ermon, and Ben Poole. Score-based generative modeling through stochastic differential equations. Int. Conf. Learn. Represent., 2021. 2 +[51] Arash Vahdat, Karsten Kreis, and Jan Kautz. Score-based generative modeling in latent space. In Adv. Neural Inform. Process. Syst., 2021. 2 +[52] Aaron Van den Oord, Nal Kalchbrenner, Lasse Espeholt, Oriol Vinyals, Alex Graves, et al. Conditional image generation with pixelCNN decoders. Adv. Neural Inform. Process. Syst., 29, 2016. 2 +[53] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Adv. Neural Inform. Process. Syst., 30, 2017. 5 +[54] Yan Wu, Jeff Donahue, David Balduzzi, Karen Simonyan, and Timothy Lillicrap. Logan: Latent optimisation for generative adversarial networks. Int. Conf. Learn. Represent., 2020. 1 +[55] Yuxin Wu and Kaiming He. Group normalization. In Eur. Conf. Comput. Vis., pages 3-19, 2018. 2 +[56] Xiulong Yang, Sheng-Min Shih, Yinlin Fu, Xiaoting Zhao, and Shihao Ji. Your vit is secretly a hybrid discriminative-generative diffusion model. arXiv preprint arXiv:2208.07791, 2022.3 +[57] Zhu Zhang, Jianxin Ma, Chang Zhou, Rui Men, Zhikang Li, Ming Ding, Jie Tang, Jingren Zhou, and Hongxia Yang. M6-ufc: Unifying multi-modal controls for conditional image synthesis. Adv. Neural Inform. Process. Syst., 2021. 3 +[58] Jinghao Zhou, Chen Wei, Huiyu Wang, Wei Shen, Cihang Xie, Alan Yuille, and Tao Kong. ibot: Image bert pre-training with online tokenizer. Int. Conf. Learn. Represent., 2022. 3 \ No newline at end of file diff --git a/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/images.zip b/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..15334a3a4ca9dc4f2de3af6480654c88f4feb774 --- /dev/null +++ b/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:cd63dbf925ed5691d8ca1aab42bb8457bdd256a0918aadc5866117b5851b291c +size 511343 diff --git a/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/layout.json b/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..f1597a5d0f250a73c5ffe9fcedb883e32bc684c9 --- /dev/null +++ b/2023/Masked Diffusion Transformer is a Strong Image Synthesizer/layout.json @@ -0,0 +1,8653 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 104, + 136, + 473, + 153 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 104, + 136, + 473, + 153 + ], + "spans": [ + { + "bbox": [ + 104, + 136, + 473, + 153 + ], + "type": "text", + "content": "Masked Diffusion Transformer is a Strong Image Synthesizer" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 110, + 174, + 465, + 202 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 174, + 465, + 202 + ], + "spans": [ + { + "bbox": [ + 110, + 174, + 465, + 202 + ], + "type": "text", + "content": "Shanghua Gao" + }, + { + "bbox": [ + 110, + 174, + 465, + 202 + ], + "type": "inline_equation", + "content": "^{1,2}" + }, + { + "bbox": [ + 110, + 174, + 465, + 202 + ], + "type": "text", + "content": " * Pan Zhou" + }, + { + "bbox": [ + 110, + 174, + 465, + 202 + ], + "type": "inline_equation", + "content": "^{2\\dagger}" + }, + { + "bbox": [ + 110, + 174, + 465, + 202 + ], + "type": "text", + "content": " Ming-Ming Cheng" + }, + { + "bbox": [ + 110, + 174, + 465, + 202 + ], + "type": "inline_equation", + "content": "^{1\\dagger}" + }, + { + "bbox": [ + 110, + 174, + 465, + 202 + ], + "type": "text", + "content": " Shuicheng Yan" + }, + { + "bbox": [ + 110, + 174, + 465, + 202 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 110, + 174, + 465, + 202 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 110, + 174, + 465, + 202 + ], + "type": "text", + "content": "Nankai University Sea AI Lab" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 102, + 204, + 474, + 216 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 102, + 204, + 474, + 216 + ], + "spans": [ + { + "bbox": [ + 102, + 204, + 474, + 216 + ], + "type": "text", + "content": "{shanghuagao, shuicheng.yan} " + }, + { + "bbox": [ + 102, + 204, + 474, + 216 + ], + "type": "inline_equation", + "content": "@" + }, + { + "bbox": [ + 102, + 204, + 474, + 216 + ], + "type": "text", + "content": " gmail.com zhoupan@sea.com cmm@nankai.edu.cn" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 139, + 243, + 186, + 255 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 139, + 243, + 186, + 255 + ], + "spans": [ + { + "bbox": [ + 139, + 243, + 186, + 255 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 267, + 282, + 500 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 267, + 282, + 500 + ], + "spans": [ + { + "bbox": [ + 45, + 267, + 282, + 500 + ], + "type": "text", + "content": "Despite its success in image synthesis, we observe that diffusion probabilistic models (DPMs) often lack contextual reasoning ability to learn the relations among object parts in an image, leading to a slow learning process. To solve this issue, we propose a Masked Diffusion Transformer (MDT) that introduces a mask latent modeling scheme to explicitly enhance the DPMs' ability to contextual relation learning among object semantic parts in an image. During training, MDT operates in the latent space to mask certain tokens. Then, an asymmetric masking diffusion transformer is designed to predict masked tokens from unmasked ones while maintaining the diffusion generation process. Our MDT can reconstruct the full information of an image from its incomplete contextual input, thus enabling it to learn the associated relations among image tokens. Experimental results show that MDT achieves superior image synthesis performance, e.g., a new SOTA FID score in the ImageNet data set, and has about " + }, + { + "bbox": [ + 45, + 267, + 282, + 500 + ], + "type": "inline_equation", + "content": "3 \\times" + }, + { + "bbox": [ + 45, + 267, + 282, + 500 + ], + "type": "text", + "content": " faster learning speed than the previous SOTA DiT. The source code is released at https://github.com/sail-sg/MDT." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 521, + 124, + 532 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 521, + 124, + 532 + ], + "spans": [ + { + "bbox": [ + 46, + 521, + 124, + 532 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 45, + 540, + 280, + 704 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 540, + 280, + 704 + ], + "spans": [ + { + "bbox": [ + 45, + 540, + 280, + 704 + ], + "type": "text", + "content": "Diffusion probabilistic models (DPMs) [11, 38] have been at the forefront of recent advances in image-level generative models, often surpassing the previously state-of-the-art (SOTA) generative adversarial networks (GANs) [4, 17, 37, 54]. Additionally, DPMs have demonstrated their success in numerous other applications, including text-to-image generation [38] and speech generation [24]. DPMs adopt a time-inverted Stochastic Differential Equation (SDE) to gradually map a Gaussian noise into a sample by multiple time steps, with each step corresponding to a network evaluation. In practice, generating a sample is time-consuming due to the thousands of time steps required for the SDE to converge. To address this issue, various generation sampling strategies [21, 32, 41] have been proposed to accelerate the in" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 300, + 241, + 528, + 350 + ], + "blocks": [ + { + "bbox": [ + 300, + 241, + 528, + 350 + ], + "lines": [ + { + "bbox": [ + 300, + 241, + 528, + 350 + ], + "spans": [ + { + "bbox": [ + 300, + 241, + 528, + 350 + ], + "type": "image", + "image_path": "f524cb6073718353db51791e480953b774e33c6eff34cb0e76e746fc172e8546.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 289, + 357, + 411, + 466 + ], + "blocks": [ + { + "bbox": [ + 289, + 357, + 411, + 466 + ], + "lines": [ + { + "bbox": [ + 289, + 357, + 411, + 466 + ], + "spans": [ + { + "bbox": [ + 289, + 357, + 411, + 466 + ], + "type": "image", + "image_path": "692b33b1879e9acc77fc48be6ad5d988561d14ba97d940bbb93f0ecac71efbd1.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 296, + 467, + 532, + 510 + ], + "lines": [ + { + "bbox": [ + 296, + 467, + 532, + 510 + ], + "spans": [ + { + "bbox": [ + 296, + 467, + 532, + 510 + ], + "type": "text", + "content": "Figure 1. Top: Visual examples of MDT/DiT [35]. Down: learning progress comparison between DiT and MDT w.r.t. training steps/time on " + }, + { + "bbox": [ + 296, + 467, + 532, + 510 + ], + "type": "inline_equation", + "content": "8 \\times \\mathrm{A}100" + }, + { + "bbox": [ + 296, + 467, + 532, + 510 + ], + "type": "text", + "content": " GPUs. MDT has about " + }, + { + "bbox": [ + 296, + 467, + 532, + 510 + ], + "type": "inline_equation", + "content": "3 \\times" + }, + { + "bbox": [ + 296, + 467, + 532, + 510 + ], + "type": "text", + "content": " faster learning speed than DiT while achieving superior FID scores." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 415, + 357, + 529, + 465 + ], + "blocks": [ + { + "bbox": [ + 415, + 357, + 529, + 465 + ], + "lines": [ + { + "bbox": [ + 415, + 357, + 529, + 465 + ], + "spans": [ + { + "bbox": [ + 415, + 357, + 529, + 465 + ], + "type": "image", + "image_path": "1ac70bcc7407644542356c9d71aaefdcde249f163e75ee8359b872e0ca7b7063.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 296, + 531, + 532, + 612 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 531, + 532, + 612 + ], + "spans": [ + { + "bbox": [ + 296, + 531, + 532, + 612 + ], + "type": "text", + "content": "ference speed. Nevertheless, improving the training speed of DPMs is less explored but highly desired. Training of DPMs also unavoidably requires a large number of time steps to ensure the convergence of SDEs, making it very computationally expensive, especially in this era where large-scale models [11,35] and data [9,14,44] are often used to improve generation performance." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 296, + 612, + 533, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 612, + 533, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 612, + 533, + 730 + ], + "type": "text", + "content": "In this work, we first observe that DPMs often struggle to learn the associated relations among object parts in an image. This leads to its slow learning process during training. Specifically, as illustrated in Fig. 1, the classical DPM, DDPM [21] with DiT [35] as the backbone, has learned the shape of a dog at the " + }, + { + "bbox": [ + 296, + 612, + 533, + 730 + ], + "type": "inline_equation", + "content": "50\\mathrm{k}" + }, + { + "bbox": [ + 296, + 612, + 533, + 730 + ], + "type": "text", + "content": "-th training step, then learns its one eye and mouth until at the " + }, + { + "bbox": [ + 296, + 612, + 533, + 730 + ], + "type": "inline_equation", + "content": "200\\mathrm{k}" + }, + { + "bbox": [ + 296, + 612, + 533, + 730 + ], + "type": "text", + "content": "-th step while missing another eye. Also, the relative position of two ears is not very accurate, even at the " + }, + { + "bbox": [ + 296, + 612, + 533, + 730 + ], + "type": "inline_equation", + "content": "300\\mathrm{k}" + }, + { + "bbox": [ + 296, + 612, + 533, + 730 + ], + "type": "text", + "content": "-th step. This learning process reveals that DPMs fail to learn the associated relations" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 77, + 42, + 119, + 72 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 77, + 42, + 119, + 72 + ], + "spans": [ + { + "bbox": [ + 77, + 42, + 119, + 72 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 151, + 41, + 470, + 73 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 151, + 41, + 470, + 73 + ], + "spans": [ + { + "bbox": [ + 151, + 41, + 470, + 73 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 55, + 709, + 278, + 719 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 709, + 278, + 719 + ], + "spans": [ + { + "bbox": [ + 55, + 709, + 278, + 719 + ], + "type": "text", + "content": "*This work was done while S. Gao was a research intern at Sea AI Lab." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 57, + 719, + 267, + 730 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 719, + 267, + 730 + ], + "spans": [ + { + "bbox": [ + 57, + 719, + 267, + 730 + ], + "type": "text", + "content": "† Pan Zhou and Ming-Ming Cheng are joint corresponding authors." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 276, + 747, + 301, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 276, + 747, + 301, + 756 + ], + "spans": [ + { + "bbox": [ + 276, + 747, + 301, + 756 + ], + "type": "text", + "content": "23164" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 45, + 106, + 280, + 176 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 106, + 280, + 176 + ], + "spans": [ + { + "bbox": [ + 45, + 106, + 280, + 176 + ], + "type": "text", + "content": "among semantic parts and independently learn each semantic part. The reason behind this phenomenon is that DPMs maximize the log probability of real data by minimizing the per-pixel prediction loss, which ignores the associated relations among object parts in an image, thus resulting in their slow learning progress." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 45, + 177, + 282, + 433 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 177, + 282, + 433 + ], + "spans": [ + { + "bbox": [ + 45, + 177, + 282, + 433 + ], + "type": "text", + "content": "Inspired by the above observation, we propose an effective Masked Diffusion Transformer (MDT) to improve the training efficiency of DPMs. MDT proposes a mask latent modeling scheme designed for transformer-based DPMs to explicitly enhance contextual learning ability and improve the associated relation learning among semantic parts in an image. Specifically, following [35, 38], MDT operates the diffusion process in the latent space to save computational costs. It masks certain image tokens and designs an asymmetric diffusion transformer structure to predict masked tokens from unmasked ones in a diffusion generation manner. To this end, the asymmetric structure contains an encoder, a side-interpolyter, and a decoder. The encoder and decoder modify the transformer block in DiT [35] by inserting global and local token position information to help predict masked tokens. The encoder only processes unmasked tokens during training handling all tokens during inference, as there are no masks. So to ensure the decoder always processes all tokens for training prediction or inference generation, a side-interpolyter implemented by a small network aims to predict masked tokens from encoder output during training, and it is removed during inference." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 45, + 435, + 280, + 656 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 435, + 280, + 656 + ], + "spans": [ + { + "bbox": [ + 45, + 435, + 280, + 656 + ], + "type": "text", + "content": "With the masking latent modeling scheme, our MDT can reconstruct the full information of an image from its contextual incomplete input, learning the associated relations among semantic parts in an image. As shown in Fig. 1, MDT typically generates two eyes of the dog at almost the same training steps, indicating that it correctly learns the associated semantics of an image by utilizing the mask latent modeling scheme. In contrast, DiT [35] cannot easily synthesize a dog with the correct semantic part relations. This comparison shows MDT's superior relation modeling and faster learning ability over DiT. Experimental results demonstrate that MDT achieves superior performance on the image synthesis task, and set the new SOTA on class-conditional image synthesis on the ImageNet dataset, as shown in Fig. 2 and Tab. 2. MDT also enjoys about " + }, + { + "bbox": [ + 45, + 435, + 280, + 656 + ], + "type": "inline_equation", + "content": "3 \\times" + }, + { + "bbox": [ + 45, + 435, + 280, + 656 + ], + "type": "text", + "content": " faster learning progress during training than the SOTA DPMs, namely DiT, as demonstrated by Fig. 1 and Tab. 1. We hope our work can inspire more work on speeding up the diffusion training process with unified representation learning." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 57, + 658, + 258, + 669 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 658, + 258, + 669 + ], + "spans": [ + { + "bbox": [ + 57, + 658, + 258, + 669 + ], + "type": "text", + "content": "The main contributions are summarised as follows:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 57, + 682, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 682, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 57, + 682, + 279, + 730 + ], + "type": "text", + "content": "- By introducing an effective mask latent modeling scheme, we proposed a masked diffusion transformer method, which, for the first time, explicitly enhances the contextual learning ability of DPMs." + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 302, + 104, + 527, + 272 + ], + "blocks": [ + { + "bbox": [ + 302, + 104, + 527, + 272 + ], + "lines": [ + { + "bbox": [ + 302, + 104, + 527, + 272 + ], + "spans": [ + { + "bbox": [ + 302, + 104, + 527, + 272 + ], + "type": "image", + "image_path": "54dd6a9f8830f3ff6229ac95d07991936d6dddf3890485b5816fc0dedd52c5b9.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 297, + 273, + 520, + 284 + ], + "lines": [ + { + "bbox": [ + 297, + 273, + 520, + 284 + ], + "spans": [ + { + "bbox": [ + 297, + 273, + 520, + 284 + ], + "type": "text", + "content": "Figure 2. Visualization of images generated by the MDT-XL/2." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "bbox": [ + 308, + 303, + 531, + 325 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 303, + 531, + 325 + ], + "spans": [ + { + "bbox": [ + 308, + 303, + 531, + 325 + ], + "type": "text", + "content": "- Experiments show that our method better synthesis images while using much less training time than SOTA." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 297, + 342, + 383, + 354 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 342, + 383, + 354 + ], + "spans": [ + { + "bbox": [ + 297, + 342, + 383, + 354 + ], + "type": "text", + "content": "2. Related works" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 297, + 361, + 456, + 372 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 361, + 456, + 372 + ], + "spans": [ + { + "bbox": [ + 297, + 361, + 456, + 372 + ], + "type": "text", + "content": "2.1. Diffusion Probabilistic models" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 379, + 532, + 636 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 379, + 532, + 636 + ], + "spans": [ + { + "bbox": [ + 296, + 379, + 532, + 636 + ], + "type": "text", + "content": "Diffusion probabilistic model (DPM) [11,21], also known as score-based model [48,49], is a competitive image synthesis approach. DPMs begin by using an evolving Stochastic Differential Equation (SDE) to gradually add Gaussian noise into real data, transforming a complex data distribution into a Gaussian distribution. Then, it adopts a time-inverted SDE to map a Gaussian noise gradually into a sample by multiple steps. At each sampling time step, a network is utilized to generate the sample along the gradient of the log probability, also known as the score function [50]. The iterative nature of diffusion models can result in high training and inference costs. Efficient sampling strategies [21,23,32,41,46], latent space diffusion [38,51], and multi-resolution cascaded generation [22] have been proposed to reduce the inference cost. Additionally, some training schemes [2, 12] are introduced to improve the diffusion model training, e.g., approximate maximum likelihood training [28, 34, 47], and training loss weighting [26, 27]. We identify the lack of contextual modeling ability in diffusion models. To address this, we propose the mask latent modeling scheme to enhance the contextual representation of diffusion models, which is orthogonal to existing diffusion training schemes." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 297, + 642, + 459, + 653 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 642, + 459, + 653 + ], + "spans": [ + { + "bbox": [ + 297, + 642, + 459, + 653 + ], + "type": "text", + "content": "2.2. Networks for Diffusion Models" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 296, + 660, + 532, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 660, + 532, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 660, + 532, + 730 + ], + "type": "text", + "content": "The UNet-like [39] network, enhanced by spatial selfattention [42,52] and group normalization [55] is firstly used for diffusion models [21]. Several design improvements, e.g., adding more attention heads [18], BigGAN [4] residual block, and adaptive group normalization, are proposed in [11] to further enhance the generation ability of the UNet." + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "spans": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "type": "text", + "content": "23165" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 45, + 106, + 281, + 280 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 106, + 281, + 280 + ], + "spans": [ + { + "bbox": [ + 45, + 106, + 281, + 280 + ], + "type": "text", + "content": "Recently, due to the broad applicability of transformer networks, several works have attempted to utilize the vision transformer (ViT) structure for diffusion models [1,35,56]. GenViT [56] demonstrates that ViT is capable of image generation but has inferior performance compared to UNet. U-ViT [1] improves ViT by adding long-skip connections and convolutional layers, achieving competitive performance with that of UNet. DiT [35] verifies the scaling ability of ViT on large model sizes and feature resolutions. Our MDT is orthogonal to these diffusion networks as it focuses on contextual representation learning. Moreover, the position-aware designs in MDT reveal that the mask latent modeling scheme benefits from a stronger diffusion network. We will explore further to release the potential of these networks with MDT." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 287, + 140, + 300 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 287, + 140, + 300 + ], + "spans": [ + { + "bbox": [ + 46, + 287, + 140, + 300 + ], + "type": "text", + "content": "2.3. Mask Modeling" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 45, + 304, + 281, + 607 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 304, + 281, + 607 + ], + "spans": [ + { + "bbox": [ + 45, + 304, + 281, + 607 + ], + "type": "text", + "content": "Mask modeling has been proven to be effective in both recognition learning [8, 10, 15, 19] and generative modeling [7, 36]. In the natural language processing (NLP) field, mask modeling was first introduced to enable representation pretraining [10, 36] and language generation [5, 25]. Subsequently, it also proved feasible for vision recognition [3] and generation [7, 16, 57] tasks. In vision recognition, pretraining schemes that utilize mask modeling enable good representation quality [58], scalability [19] and faster convergence [15]. In generative modeling, following the bidirectional generative modeling in NLP, MaskGIT [7] and MUSE [6] use the masked generative transformer to predict randomly masked image tokens for image generation. Similarly, VQ-Diffusion [16] presents a mask-replace diffusion strategy to generate images. In contrast, our MDT aims to enhance the contextual representation of the denoising diffusion transformer [35] with mask latent modeling. This preserves the detail refinement ability of denoising diffusion models by maintaining the diffusion process during inference. To ensure that the mask latent modeling in MDT focuses on representation learning instead of reconstruction, we propose an asymmetrical structure in mask modeling training. As an extra benefit, it enables lower training costs than masked generative models because it skips the masked patches in training instead of replacing masked input patches with a mask token." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 617, + 215, + 629 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 617, + 215, + 629 + ], + "spans": [ + { + "bbox": [ + 45, + 617, + 215, + 629 + ], + "type": "text", + "content": "3. Masked Diffusion Transformer" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 45, + 636, + 280, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 636, + 280, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 636, + 280, + 730 + ], + "type": "text", + "content": "Revisit Diffusion Probabilistic Model. For diffusion probabilistic models [11, 45], such as DDPM [21] and DDIM [46], training involves a forward noising process and a reverse denoising process. In the forward noising process, Gaussian noise " + }, + { + "bbox": [ + 45, + 636, + 280, + 730 + ], + "type": "inline_equation", + "content": "\\epsilon \\sim \\mathcal{N}(0,\\mathbf{I})" + }, + { + "bbox": [ + 45, + 636, + 280, + 730 + ], + "type": "text", + "content": " is gradually added to the real sample " + }, + { + "bbox": [ + 45, + 636, + 280, + 730 + ], + "type": "inline_equation", + "content": "x_0" + }, + { + "bbox": [ + 45, + 636, + 280, + 730 + ], + "type": "text", + "content": " via a discrete SDE formulation [46]. If the time step " + }, + { + "bbox": [ + 45, + 636, + 280, + 730 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 45, + 636, + 280, + 730 + ], + "type": "text", + "content": " is large, " + }, + { + "bbox": [ + 45, + 636, + 280, + 730 + ], + "type": "inline_equation", + "content": "x_{t}" + }, + { + "bbox": [ + 45, + 636, + 280, + 730 + ], + "type": "text", + "content": " would be a Gaussian noise. Similarly, the reverse denoising process is a discrete SDE that grad" + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 299, + 103, + 532, + 246 + ], + "blocks": [ + { + "bbox": [ + 299, + 103, + 532, + 246 + ], + "lines": [ + { + "bbox": [ + 299, + 103, + 532, + 246 + ], + "spans": [ + { + "bbox": [ + 299, + 103, + 532, + 246 + ], + "type": "image", + "image_path": "f6cbb90df5f4411a0741afb1b35c1282697025c33bd71cb9d75fbf0a09ac5078.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 296, + 248, + 532, + 293 + ], + "lines": [ + { + "bbox": [ + 296, + 248, + 532, + 293 + ], + "spans": [ + { + "bbox": [ + 296, + 248, + 532, + 293 + ], + "type": "text", + "content": "Figure 3. The overall framework of Masked Diffusion Transformer (MDT). Solid/dotted lines indicate each time step's training/inference process. Masking and side-interpolater are only used during training and are removed during inference." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "spans": [ + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "text", + "content": "ually maps a Gaussian noise into a sample. At each time step, given " + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "inline_equation", + "content": "x_{t}" + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "text", + "content": ", it predicts the next reverse step " + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "inline_equation", + "content": "p_{\\theta}(x_{t - 1}|x_t)" + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "text", + "content": " via a network. Following [34, 35], the network is trained by optimizing the variational lower-bound " + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{vlb}}" + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "text", + "content": " of the log-likelihood " + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "inline_equation", + "content": "p_{\\theta}(x_0)" + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "text", + "content": " [45]. During inference, one can sample a Gaussian noise and then gradually reverses to a sample " + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "inline_equation", + "content": "x_0" + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "text", + "content": ". Same as [34, 35], we train the diffusion model conditioned with class label " + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "inline_equation", + "content": "c" + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "text", + "content": ", i.e. " + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "inline_equation", + "content": "p_{\\theta}(x_{t - 1}|x_t,c)" + }, + { + "bbox": [ + 296, + 309, + 532, + 415 + ], + "type": "text", + "content": ". By default, we use class-conditioned image generation in our experiments." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 297, + 421, + 363, + 431 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 421, + 363, + 431 + ], + "spans": [ + { + "bbox": [ + 297, + 421, + 363, + 431 + ], + "type": "text", + "content": "3.1. Overview" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 296, + 438, + 530, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 438, + 530, + 590 + ], + "spans": [ + { + "bbox": [ + 296, + 438, + 530, + 590 + ], + "type": "text", + "content": "As shown in Fig. 1, DPMs with DiT backbone exhibit slow training convergence due to the slowly learning of the associated relations among semantic parts in an image. To relieve this issue, we propose Masked Diffusion Transformer (MDT), which introduces a mask latent modeling scheme to enhance contextual learning ability explicitly. To this end, as depicted in Fig. 3, MDT consists of 1) a latent masking operation to mask the input image in the latent space, and 2) an asymmetric masking diffusion transformer structure that performs vanilla diffusion process as DPMs, but with masked input. To reduce computational costs, MDT follows LatentDiffusion [38] to perform generative learning in the latent space instead of raw pixel space." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 590, + 532, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 590, + 532, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 590, + 532, + 730 + ], + "type": "text", + "content": "In the training phase, MDT first encodes an image into a latent space with a pre-trained VAE encoder [38]. Then, MDT adds Gaussian noise into the image latent embedding. The latent masking operation in MDT then patchifies the resulting noisy latent embedding into a sequence of tokens, and masks certain tokens. The remaining unmasked tokens are fed into the asymmetric masking diffusion transformer, as shown in Fig. 4(a), which contains an encoder, a side-interpolater, and a decoder to predict the masked tokens from the unmasked ones. During inference, MDT replaces the side-interpolater with additional position embedding. MDT takes the latent embedding of a Gaussian noise as input to" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 276, + 747, + 301, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 276, + 747, + 301, + 756 + ], + "spans": [ + { + "bbox": [ + 276, + 747, + 301, + 756 + ], + "type": "text", + "content": "23166" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 45, + 106, + 279, + 129 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 106, + 279, + 129 + ], + "spans": [ + { + "bbox": [ + 45, + 106, + 279, + 129 + ], + "type": "text", + "content": "generate the denoised latent embedding, which is then passed to a pre-trained VAE decoder [38] for image generation." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 45, + 130, + 280, + 350 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 130, + 280, + 350 + ], + "spans": [ + { + "bbox": [ + 45, + 130, + 280, + 350 + ], + "type": "text", + "content": "The above masking latent modeling scheme in the training phase forces the diffusion model to reconstruct the full information of an image from its contextual incomplete input. Thus, the model is encouraged to learn the relations among image latent tokens, particularly the associated relations among semantic parts in an image. For example, as illustrated in Fig. 3, the model should first understand the correct associated relations among small image parts (tokens) of the dog image. Then, it should generate the masked \"eye\" tokens using other unmasked tokens as contextual information. Furthermore, Fig. 1 shows that MDT often learns to generate the associated semantics of an image at nearly the same pace, such as the generation of the dog's two eyes (two ears) at almost the same training step. While DiT [35] (DDPM with transformer backbone) learns to generate one eye (one ear) initially and then learns to generate another eye (ear) after roughly 100k training steps. This demonstrates the superior learning ability of MDT over DiT in terms of the associated relation learning of image semantics." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 45, + 351, + 279, + 386 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 351, + 279, + 386 + ], + "spans": [ + { + "bbox": [ + 45, + 351, + 279, + 386 + ], + "type": "text", + "content": "In the following parts, we will introduce the two key components of MDT, 1) a latent masking operation, and 2) an asymmetric masking diffusion transformer structure." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 392, + 140, + 404 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 392, + 140, + 404 + ], + "spans": [ + { + "bbox": [ + 46, + 392, + 140, + 404 + ], + "type": "text", + "content": "3.2. Latent Masking" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 45, + 410, + 280, + 468 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 410, + 280, + 468 + ], + "spans": [ + { + "bbox": [ + 45, + 410, + 280, + 468 + ], + "type": "text", + "content": "Following the Latent diffusion model (LDM) [38], MDT performs generation learning in the latent space instead of raw pixel space to reduce computational costs. In the following, we briefly recall LDM and then introduce our latent masking operation on the latent input." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "spans": [ + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": "Latent diffusion model (LDM). LDM employs a pretrained VAE encoder " + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "inline_equation", + "content": "\\mathbf{E}" + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": " to encode an image " + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "inline_equation", + "content": "v\\in \\mathbb{R}^{3\\times H\\times W}" + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": " to a latent embedding " + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "inline_equation", + "content": "z = \\mathbf{E}(v)\\in \\mathbb{R}^{c\\times h\\times w}" + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": ". It gradually adds noise to " + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": " in the forward process and then denoises to predict " + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": " in the reverse process. Finally, LDM uses a pre-trained VAE decoder " + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "inline_equation", + "content": "\\mathbf{D}" + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": " to decode " + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": " into a high-resolution image " + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "inline_equation", + "content": "v = \\mathbf{D}(z)" + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": ". Both the VAE encoder and decoder are fixed during training and inference. Since " + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "inline_equation", + "content": "h" + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": " are smaller than " + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "inline_equation", + "content": "H" + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "inline_equation", + "content": "W" + }, + { + "bbox": [ + 45, + 481, + 279, + 598 + ], + "type": "text", + "content": ", performing the diffusion process in the low-resolution latent space is more efficient than pixel space." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "text", + "content": "Latent masking operation. We first add Gaussian noise to an image's latent embedding " + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "text", + "content": " during training. Then following [35], we divide the noisy embedding " + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "text", + "content": " into a sequence of " + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "inline_equation", + "content": "p \\times p" + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "text", + "content": "-sized tokens and concatenate them to a matrix " + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "inline_equation", + "content": "u \\in \\mathbb{R}^{d \\times N}" + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "text", + "content": " is the channel number and " + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "text", + "content": " is the number of tokens. Next, we randomly mask tokens with a ratio " + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "inline_equation", + "content": "\\rho" + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "text", + "content": " and concatenate the remaining tokens as " + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "inline_equation", + "content": "\\hat{u} \\in \\mathbb{R}^{d \\times \\hat{N}}" + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "inline_equation", + "content": "\\hat{N} = \\rho N" + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "text", + "content": ". Accordingly, we can create a binary mask " + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "inline_equation", + "content": "M \\in \\mathbb{R}^N" + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "text", + "content": " in which one (zero) denotes the masked (unmasked) tokens. Finally, we feed the tokens " + }, + { + "bbox": [ + 45, + 612, + 279, + 730 + ], + "type": "inline_equation", + "content": "\\hat{u}" + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 300, + 104, + 530, + 197 + ], + "blocks": [ + { + "bbox": [ + 300, + 104, + 530, + 197 + ], + "lines": [ + { + "bbox": [ + 300, + 104, + 530, + 197 + ], + "spans": [ + { + "bbox": [ + 300, + 104, + 530, + 197 + ], + "type": "image", + "image_path": "6e8cfbab54ad0416c1621b736a568ae60e21daec418f45fba591a96fa2584553.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 300, + 200, + 530, + 269 + ], + "blocks": [ + { + "bbox": [ + 300, + 200, + 530, + 269 + ], + "lines": [ + { + "bbox": [ + 300, + 200, + 530, + 269 + ], + "spans": [ + { + "bbox": [ + 300, + 200, + 530, + 269 + ], + "type": "image", + "image_path": "f4cb86fc985d4b48df6ca0e48d16eee101b1e0b49205d3e21e8cb54367a9b812.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 299, + 275, + 530, + 398 + ], + "blocks": [ + { + "bbox": [ + 299, + 275, + 530, + 398 + ], + "lines": [ + { + "bbox": [ + 299, + 275, + 530, + 398 + ], + "spans": [ + { + "bbox": [ + 299, + 275, + 530, + 398 + ], + "type": "image", + "image_path": "867e8bee79ceb5d3bcd61cf25a7922e807753d9aba58eaaa49a9dba627ba7462.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 296, + 406, + 531, + 450 + ], + "lines": [ + { + "bbox": [ + 296, + 406, + 531, + 450 + ], + "spans": [ + { + "bbox": [ + 296, + 406, + 531, + 450 + ], + "type": "text", + "content": "Figure 4. The asymmetric masking diffusion transformer structure in MDT. We modify the DiT [35] by adding a side-interpolater, local relative positional bias, and learnable global position embeddings. The conditional scheme is omitted for simplicity." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 468, + 530, + 551 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 468, + 530, + 551 + ], + "spans": [ + { + "bbox": [ + 296, + 468, + 530, + 551 + ], + "type": "text", + "content": "into our diffusion model for processing. We only use tokens " + }, + { + "bbox": [ + 296, + 468, + 530, + 551 + ], + "type": "inline_equation", + "content": "\\hat{u}" + }, + { + "bbox": [ + 296, + 468, + 530, + 551 + ], + "type": "text", + "content": " for two reasons. 1) The model should focus on learning semantics instead of predicting the masked tokens. As shown in Sec. 4.3, it achieves better performance than replacing the masked tokens with a learnable mask token and then processing all tokens like [3, 6, 7]; 2) It saves the training cost compared to processing all " + }, + { + "bbox": [ + 296, + 468, + 530, + 551 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 296, + 468, + 530, + 551 + ], + "type": "text", + "content": " tokens." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 297, + 558, + 523, + 570 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 558, + 523, + 570 + ], + "spans": [ + { + "bbox": [ + 297, + 558, + 523, + 570 + ], + "type": "text", + "content": "3.3. Asymmetric Masking Diffusion Transformer" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 575, + 531, + 633 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 575, + 531, + 633 + ], + "spans": [ + { + "bbox": [ + 296, + 575, + 531, + 633 + ], + "type": "text", + "content": "We introduce our asymmetric masking diffusion transformer for joint training of mask latent modeling and diffusion process. As shown in Fig. 4(a), it consists of three components: an encoder, a side-interpolyater, and a decoder, each of which is described in detail below." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 296, + 648, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 648, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 648, + 530, + 730 + ], + "type": "text", + "content": "Position-aware encoder and decoder. In MDT, predicting the masked latent tokens from the unmasked tokens requires the position relations of all tokens. To enhance the position information in the model, we propose a positional-aware encoder and decoder that facilitate the learning of the masked latent tokens. Specifically, the encoder and decoder tailor the standard DiT block via adding two types of token position" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "spans": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "type": "text", + "content": "23167" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 45, + 106, + 279, + 129 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 106, + 279, + 129 + ], + "spans": [ + { + "bbox": [ + 45, + 106, + 279, + 129 + ], + "type": "text", + "content": "information containing " + }, + { + "bbox": [ + 45, + 106, + 279, + 129 + ], + "type": "inline_equation", + "content": "N_{1}" + }, + { + "bbox": [ + 45, + 106, + 279, + 129 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 45, + 106, + 279, + 129 + ], + "type": "inline_equation", + "content": "N_{2}" + }, + { + "bbox": [ + 45, + 106, + 279, + 129 + ], + "type": "text", + "content": " blocks, as illustrated in Fig. 4(a)." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 45, + 129, + 280, + 245 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 129, + 280, + 245 + ], + "spans": [ + { + "bbox": [ + 45, + 129, + 280, + 245 + ], + "type": "text", + "content": "Firstly, the encoder adds the conventional learnable global position embedding into the noisy latent embedding input. Similarly, the decoder introduces the learnable position embedding into its input but with different training and inference phase approaches. The side-interpolater already uses the learnable global position embedding introduced below during training. During inference, since the side interpolater is discarded (see below), the decoder explicitly adds the position embedding into its input to enhance positional information." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 45, + 245, + 280, + 293 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 245, + 280, + 293 + ], + "spans": [ + { + "bbox": [ + 45, + 245, + 280, + 293 + ], + "type": "text", + "content": "Secondly, as depicted in Fig. 4(b), the encoder and decoder add a local relative positional bias [30] to each head in each block when computing the attention score of the self-attention [53]:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 61, + 298, + 263, + 325 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 298, + 263, + 325 + ], + "spans": [ + { + "bbox": [ + 61, + 298, + 263, + 325 + ], + "type": "interline_equation", + "content": "\\operatorname {A t t e n t i o n} (Q, K, V) = \\operatorname {S o f t m a x} \\left(\\frac {Q K ^ {\\top}}{\\sqrt {d _ {k}}} + B _ {r}\\right) V,", + "image_path": "891b6ea6ea46cf983e1c4451eeea99a4e4f10470e21d25618829ea6eb4e0bf5a.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "spans": [ + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "inline_equation", + "content": "V" + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "text", + "content": ", respectively denote the query, key, and value in the self-attention module, " + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "inline_equation", + "content": "d_k" + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "text", + "content": " is the dimension of the key, and " + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "inline_equation", + "content": "B_r \\in \\mathbb{R}^{N \\times N}" + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "text", + "content": " is the relative positional bias. " + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "inline_equation", + "content": "B_r" + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "text", + "content": " is selected by the relative positional difference between the " + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 45, + 330, + 279, + 423 + ], + "type": "text", + "content": "-th position and other positions, which is updated during training. The local relative positional bias helps to capture the relative relations among tokens, facilitating the masking of latent modeling." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 424, + 280, + 527 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 424, + 280, + 527 + ], + "spans": [ + { + "bbox": [ + 45, + 424, + 280, + 527 + ], + "type": "text", + "content": "The encoder takes the unmasked noisy latent embedding provided by our latent masking operation and feeds its output into the side-interpolater/decoder during training/inference. For the decoder, its input is the output of the side-interpolater for training or the combination of the encoder output and the learnable position embedding for inference. During training, the encoder and decoder, respectively, handle unmasked tokens and full tokens. Thus, we name our model the \"asymmetric\" model." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 542, + 279, + 670 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 542, + 279, + 670 + ], + "spans": [ + { + "bbox": [ + 45, + 542, + 279, + 670 + ], + "type": "text", + "content": "Side-interpolater. As shown in Fig. 3, during training, for efficiency and better performance, the encoder only processes the unmasked tokens " + }, + { + "bbox": [ + 45, + 542, + 279, + 670 + ], + "type": "inline_equation", + "content": "\\hat{u}" + }, + { + "bbox": [ + 45, + 542, + 279, + 670 + ], + "type": "text", + "content": ". While in the inference phase, the encoder handles all tokens " + }, + { + "bbox": [ + 45, + 542, + 279, + 670 + ], + "type": "inline_equation", + "content": "u" + }, + { + "bbox": [ + 45, + 542, + 279, + 670 + ], + "type": "text", + "content": " due to the lack of masks. This means that there is a big difference in the encoder output (i.e., decoder input) during training and inference, at least in terms of token number. To ensure the decoder always processes all tokens for training prediction or inference generation, a side-interpolyter implemented by a small network aims to predict masked tokens from encoder output during training and would be removed during inference." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 45, + 670, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 670, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 670, + 279, + 730 + ], + "type": "text", + "content": "In the training phase, the encoder processes the unmasked tokens to obtain its output token embedding " + }, + { + "bbox": [ + 45, + 670, + 279, + 730 + ], + "type": "inline_equation", + "content": "\\hat{q} \\in \\mathbb{R}^{d \\times \\hat{N}}" + }, + { + "bbox": [ + 45, + 670, + 279, + 730 + ], + "type": "text", + "content": ". Then, as shown in Fig. 4(c), the side-interpolater first fills the masked positions, indicated by the mask " + }, + { + "bbox": [ + 45, + 670, + 279, + 730 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 45, + 670, + 279, + 730 + ], + "type": "text", + "content": " defined in Sec. 3.2, by a shared learnable mask token, and also adds" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "spans": [ + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "text", + "content": "a learnable positional embedding to obtain an embedding " + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "inline_equation", + "content": "q \\in \\mathbb{R}^{d \\times N}" + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "text", + "content": ". Next, we use a basic encoder block to process " + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "inline_equation", + "content": "q" + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "text", + "content": " to predict an interpolated embedding " + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "inline_equation", + "content": "\\hat{k}" + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "text", + "content": ". The " + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "inline_equation", + "content": "\\hat{k}" + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "text", + "content": " tokens denote the predicted tokens. Finally, we use a masked shortcut connection to combine prediction " + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "inline_equation", + "content": "\\hat{k}" + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "inline_equation", + "content": "q" + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "inline_equation", + "content": "k = M \\cdot q + (1 - M) \\cdot \\hat{k}" + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "text", + "content": ". In summary, for masked tokens, we use the prediction by side-interpolyter. For unmasked tokens, we still adopt the corresponding tokens in " + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "inline_equation", + "content": "q" + }, + { + "bbox": [ + 296, + 106, + 531, + 223 + ], + "type": "text", + "content": ". This can 1) boost the consistency between training and inference phases, 2) eliminates the mask-reconstruction process in the decoder." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 296, + 223, + 532, + 315 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 223, + 532, + 315 + ], + "spans": [ + { + "bbox": [ + 296, + 223, + 532, + 315 + ], + "type": "text", + "content": "Since there are no masks during inference, the side-interpolater is replaced by a position embedding operation, which adds the learnable position embeddings of the side-interpolater, learned during training. This ensures the decoder always processes all tokens and uses the same learnable position embeddings for training prediction or inference generation, thus having better image generation performance." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 297, + 322, + 359, + 335 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 322, + 359, + 335 + ], + "spans": [ + { + "bbox": [ + 297, + 322, + 359, + 335 + ], + "type": "text", + "content": "3.4. Training" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 340, + 532, + 479 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 340, + 532, + 479 + ], + "spans": [ + { + "bbox": [ + 296, + 340, + 532, + 479 + ], + "type": "text", + "content": "During training, we feed both full latent embedding " + }, + { + "bbox": [ + 296, + 340, + 532, + 479 + ], + "type": "inline_equation", + "content": "u" + }, + { + "bbox": [ + 296, + 340, + 532, + 479 + ], + "type": "text", + "content": " and the masked latent embedding " + }, + { + "bbox": [ + 296, + 340, + 532, + 479 + ], + "type": "inline_equation", + "content": "\\hat{u}" + }, + { + "bbox": [ + 296, + 340, + 532, + 479 + ], + "type": "text", + "content": " to the diffusion model. We observe that only using masked latent embedding makes the model focus too much on masked region reconstruction, while ignoring the diffusion training. Full/masked latent inputs are independently sent to the network, and the training objectives optimize the variational lower-bound, as in [34, 35]. Due to the asymmetrical masking structure, the extra costs for using masked latent embedding are small. This is also demonstrated by Fig. 1, which shows that MDT still achieves about " + }, + { + "bbox": [ + 296, + 340, + 532, + 479 + ], + "type": "inline_equation", + "content": "3 \\times" + }, + { + "bbox": [ + 296, + 340, + 532, + 479 + ], + "type": "text", + "content": " faster learning progress than previous SOTA DiT in total training hours." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 297, + 490, + 376, + 502 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 490, + 376, + 502 + ], + "spans": [ + { + "bbox": [ + 297, + 490, + 376, + 502 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 297, + 508, + 392, + 521 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 508, + 392, + 521 + ], + "spans": [ + { + "bbox": [ + 297, + 508, + 392, + 521 + ], + "type": "text", + "content": "4.1. Implementation" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 297, + 526, + 530, + 550 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 526, + 530, + 550 + ], + "spans": [ + { + "bbox": [ + 297, + 526, + 530, + 550 + ], + "type": "text", + "content": "We give the implementation details of MDT, including model architecture, training details, and evaluation metrics." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 296, + 563, + 532, + 704 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 563, + 532, + 704 + ], + "spans": [ + { + "bbox": [ + 296, + 563, + 532, + 704 + ], + "type": "text", + "content": "Model architecture. We follow DiT [35] to set the total block number (i.e., " + }, + { + "bbox": [ + 296, + 563, + 532, + 704 + ], + "type": "inline_equation", + "content": "N_{1} + N_{2}" + }, + { + "bbox": [ + 296, + 563, + 532, + 704 + ], + "type": "text", + "content": "), token number, and channel numbers of the diffusion transformer of MDT. As DiT reveals stronger synthesis performance when using a smaller patch size, we also use a patch size " + }, + { + "bbox": [ + 296, + 563, + 532, + 704 + ], + "type": "inline_equation", + "content": "p = 2" + }, + { + "bbox": [ + 296, + 563, + 532, + 704 + ], + "type": "text", + "content": " by default, denoted by MDT-/2. Moreover, We also follow DiT's parameters to design MDT for getting its small-, base-, and xlarge-sized model, denoted by MDT-S/B/XL. Same as LatentDiffusion [38] and DiT, MDT adopts the fixed " + }, + { + "bbox": [ + 296, + 563, + 532, + 704 + ], + "type": "inline_equation", + "content": "\\mathrm{VAE}^{1}" + }, + { + "bbox": [ + 296, + 563, + 532, + 704 + ], + "type": "text", + "content": " provided by the Stable Diffusion to encode/decode the image/latent tokens by default. The VAE encoder has a downsampling ratio of " + }, + { + "bbox": [ + 296, + 563, + 532, + 704 + ], + "type": "inline_equation", + "content": "1 / 8" + }, + { + "bbox": [ + 296, + 563, + 532, + 704 + ], + "type": "text", + "content": ", and a feature channel dimension of 4, e.g., an image" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 297, + 709, + 531, + 730 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 709, + 531, + 730 + ], + "spans": [ + { + "bbox": [ + 297, + 709, + 531, + 730 + ], + "type": "text", + "content": "1The model is downloaded in https://huggingface.co/stabilityai/sd-vae-ft-mse" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 276, + 747, + 301, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 276, + 747, + 301, + 756 + ], + "spans": [ + { + "bbox": [ + 276, + 747, + 301, + 756 + ], + "type": "text", + "content": "23168" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 47, + 104, + 278, + 288 + ], + "blocks": [ + { + "bbox": [ + 47, + 104, + 278, + 288 + ], + "lines": [ + { + "bbox": [ + 47, + 104, + 278, + 288 + ], + "spans": [ + { + "bbox": [ + 47, + 104, + 278, + 288 + ], + "type": "table", + "html": "
MethodImage Res.Training Steps (k)FID-50K↓
DiT-S/2256×25640068.40
MDT-S/2256×25630057.01
MDT-S/2256×25640053.46
MDT-S/2256×256200044.14
MDT-S/2256×256350041.37
DiT-B/2256×25640043.47
MDT-B/2256×25640034.33
MDT-B/2256×256350020.45
DiT-XL/2256×25640019.47
DiT-XL/2256×256235210.67
DiT-XL/2256×25670009.62
MDT-XL/2256×25640016.42
MDT-XL/2256×25613009.60
MDT-XL/2256×25635006.65
", + "image_path": "f1593e333238d28ac71a06e0dce3f601b9290826b29a930c590166ac23491d35.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 45, + 345, + 279, + 368 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 345, + 279, + 368 + ], + "spans": [ + { + "bbox": [ + 45, + 345, + 279, + 368 + ], + "type": "text", + "content": "of size " + }, + { + "bbox": [ + 45, + 345, + 279, + 368 + ], + "type": "inline_equation", + "content": "256 \\times 256 \\times 3" + }, + { + "bbox": [ + 45, + 345, + 279, + 368 + ], + "type": "text", + "content": " is encoded into a latent embedding of size " + }, + { + "bbox": [ + 45, + 345, + 279, + 368 + ], + "type": "inline_equation", + "content": "32 \\times 32 \\times 4" + }, + { + "bbox": [ + 45, + 345, + 279, + 368 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 45, + 384, + 279, + 479 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 384, + 279, + 479 + ], + "spans": [ + { + "bbox": [ + 45, + 384, + 279, + 479 + ], + "type": "text", + "content": "Training details. Following [35], all models are trained by AdamW [31] optimizer of 3e-4 learning rate, 256 batch size, and without weight decay on ImageNet [9] with an image resolution of " + }, + { + "bbox": [ + 45, + 384, + 279, + 479 + ], + "type": "inline_equation", + "content": "256 \\times 256" + }, + { + "bbox": [ + 45, + 384, + 279, + 479 + ], + "type": "text", + "content": ". We set the mask ratio as 0.3 and " + }, + { + "bbox": [ + 45, + 384, + 279, + 479 + ], + "type": "inline_equation", + "content": "N_{2} = 2" + }, + { + "bbox": [ + 45, + 384, + 279, + 479 + ], + "type": "text", + "content": ". Following the training settings in DiT, we set the maximum step in training to 1000 and use the linear variance schedule with a range from " + }, + { + "bbox": [ + 45, + 384, + 279, + 479 + ], + "type": "inline_equation", + "content": "10^{-4}" + }, + { + "bbox": [ + 45, + 384, + 279, + 479 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 45, + 384, + 279, + 479 + ], + "type": "inline_equation", + "content": "2 \\times 10^{-2}" + }, + { + "bbox": [ + 45, + 384, + 279, + 479 + ], + "type": "text", + "content": ". Other settings are also aligned with DiT." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 45, + 494, + 280, + 633 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 494, + 280, + 633 + ], + "spans": [ + { + "bbox": [ + 45, + 494, + 280, + 633 + ], + "type": "text", + "content": "Evaluation. We evaluate models with commonly used metrics, i.e. Frechet Inception Distance (FID) [20], sFID [33], Inception Score (IS) [40], Precision and Recall [29]. The FID is used as the major metric as it measures both diversity and fidelity. sFID improves upon FID by evaluating at the spatial level. As a complement, IS and Precision are used for measuring fidelity, and Recall is used to measure diversity. For fair comparisons, we follow [35] to use the TensorFlow evaluation suite from ADM [11] and report FID-50K with 250 DDPM sampling steps. Unless specified otherwise, we report the FID scores without the classifier-free guidance [23]." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 641, + 160, + 654 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 641, + 160, + 654 + ], + "spans": [ + { + "bbox": [ + 45, + 641, + 160, + 654 + ], + "type": "text", + "content": "4.2. Comparison Results" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 45, + 660, + 279, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 660, + 279, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 660, + 279, + 730 + ], + "type": "text", + "content": "Performance comparison. Tab. 1 compares our MDT with the SOTA DiT under different model sizes. It is evident that MDT achieves higher FID scores for all model scales with fewer training costs. The parameters and inference cost of MDTs are similar to DiT, since the extra modules in MDT are negligible as introduced in Sec. 3.1. For small models," + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 298, + 105, + 530, + 394 + ], + "blocks": [ + { + "bbox": [ + 45, + 293, + 279, + 326 + ], + "lines": [ + { + "bbox": [ + 45, + 293, + 279, + 326 + ], + "spans": [ + { + "bbox": [ + 45, + 293, + 279, + 326 + ], + "type": "text", + "content": "Table 1. Comparison between DiT [35] and MDT under different model sizes and training steps on ImageNet " + }, + { + "bbox": [ + 45, + 293, + 279, + 326 + ], + "type": "inline_equation", + "content": "256\\times 256" + }, + { + "bbox": [ + 45, + 293, + 279, + 326 + ], + "type": "text", + "content": ". DiT results are obtained from DiT reported results." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 298, + 105, + 530, + 394 + ], + "lines": [ + { + "bbox": [ + 298, + 105, + 530, + 394 + ], + "spans": [ + { + "bbox": [ + 298, + 105, + 530, + 394 + ], + "type": "table", + "html": "
MethodCost(ITer×BS)FID↓sFID↓IS↑Prec.↑Rec.↑
DCTrans. [33]-36.51--0.360.67
VQVAE-2 [37]-31.11--0.360.57
VQGAN [13]-15.7878.3---
BigGAN-deep [4]-6.957.36171.40.870.28
StyleGAN [43]-2.304.02265.120.780.53
Impr. DDPM [34]-12.26--0.700.62
MaskGIT [7]1387k×2566.18-182.10.800.51
CDM [22]-4.88-158.71--
ADM [11]1980k×25610.946.02100.980.690.63
LDM-8 [38]4800k×6415.51-79.030.650.63
LDM-4178k×120010.56-103.490.710.62
DiT-XL/2 [35]7000k×2569.626.85121.500.670.67
MDT2500k×2567.414.95121.220.720.64
MDT3500k×2566.464.92131.700.720.63
MDT6500k×2566.235.23143.020.710.65
ADM-G [11]1980k×2564.595.25186.700.820.52
ADM-G, U1980k×2563.946.14215.840.830.53
LDM-8-G [38]4800k×647.76-209.520.840.35
LDM-4-G178k×12003.60-247.670.870.48
U-ViT-G [1]300k×10243.40----
DiT-XL/2-G [35]7000k×2562.274.60278.240.830.57
MDT-G2500k×2562.154.52249.270.820.58
MDT-G3500k×2562.024.46263.770.820.60
MDT-G6500k×2561.794.57283.010.810.61
", + "image_path": "3dac5958423c398819d1ced05c116ca7e636a5840228b619cab6261fc8475e6b.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 296, + 404, + 530, + 458 + ], + "lines": [ + { + "bbox": [ + 296, + 404, + 530, + 458 + ], + "spans": [ + { + "bbox": [ + 296, + 404, + 530, + 458 + ], + "type": "text", + "content": "Table 2. Comparison with existing methods on class-conditional image generation with the ImageNet " + }, + { + "bbox": [ + 296, + 404, + 530, + 458 + ], + "type": "inline_equation", + "content": "256 \\times 256" + }, + { + "bbox": [ + 296, + 404, + 530, + 458 + ], + "type": "text", + "content": " dataset. -G denotes the results with classifier-free guidance [23]. Results of MDT-XL/2 model are given for comparison. Compared results are obtained from their papers." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 296, + 482, + 531, + 576 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 482, + 531, + 576 + ], + "spans": [ + { + "bbox": [ + 296, + 482, + 531, + 576 + ], + "type": "text", + "content": "MDT-S/2 trained with 300k steps outperforms the DiT-S/2 trained with 400k steps by a large margin on FID (57.01 vs. 68.40). More importantly, MDT-S/2 trained with 2000k steps achieves similar performance with a larger model DiT-B/2 trained with a similar computational budget. For the largest model, MDT-XL/2 trained with 1300k steps outperforms DiT-XL/2 trained with 7000k steps on FID (9.60 vs. 9.62), achieving about " + }, + { + "bbox": [ + 296, + 482, + 531, + 576 + ], + "type": "inline_equation", + "content": "5 \\times" + }, + { + "bbox": [ + 296, + 482, + 531, + 576 + ], + "type": "text", + "content": " faster training progress." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 579, + 532, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 579, + 532, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 579, + 532, + 730 + ], + "type": "text", + "content": "We also compare the class-conditional image generation performance of MDT with existing methods in Tab. 2. To make fair comparisons with DiT, we also use the EMA weights of VAE decoder in this table. Under class-conditional settings, MDT with half training iterations outperforms DiT by a large margin, e.g., 6.83 vs 9.62 in FID. Following previous works [1, 11, 35, 38], we utilize an improved classifier-free guidance [23] with a power-cosine weight scaling to trade off between precision and recall during class-conditional sampling. MDT achieves superior performance over previous SOTA DiT and other methods with the FID score of 1.81, setting a new SOTA for class-conditional image generation. Similar to DiT, we never" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "spans": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "type": "text", + "content": "23169" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 104, + 274, + 213 + ], + "blocks": [ + { + "bbox": [ + 48, + 104, + 274, + 213 + ], + "lines": [ + { + "bbox": [ + 48, + 104, + 274, + 213 + ], + "spans": [ + { + "bbox": [ + 48, + 104, + 274, + 213 + ], + "type": "table", + "html": "
Mask RatioFID↓sFID↓IS↑Precision↑Recall↑
0.151.6010.2326.650.440.60
0.251.4410.0926.750.440.58
0.350.2610.0827.610.450.60
0.450.8810.2127.440.450.60
0.551.579.9227.140.440.60
0.653.2010.3626.550.440.61
0.752.9010.0326.510.440.61
0.853.7310.1525.550.430.61
", + "image_path": "0475b28be2b06848cf2b82f3e93a41b6301b0cb257a521482f548fc2ae776fff.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 48, + 248, + 274, + 325 + ], + "blocks": [ + { + "bbox": [ + 46, + 218, + 278, + 239 + ], + "lines": [ + { + "bbox": [ + 46, + 218, + 278, + 239 + ], + "spans": [ + { + "bbox": [ + 46, + 218, + 278, + 239 + ], + "type": "text", + "content": "Table 3. Effect of different masking ratios. MDT-S/2 trained with 600k iterations." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 248, + 274, + 325 + ], + "lines": [ + { + "bbox": [ + 48, + 248, + 274, + 325 + ], + "spans": [ + { + "bbox": [ + 48, + 248, + 274, + 325 + ], + "type": "table", + "html": "
Decoder pos.FID↓sFID↓IS↑Precision↑Recall↑
Last051.059.9727.310.440.60
Last150.969.9027.630.450.60
Last250.2610.0827.610.450.60
Last451.6710.1226.910.450.60
Last652.6410.3626.460.440.60
", + "image_path": "2d85541f4505e3ee89b1a071d363ef2284aab467c37a2fee417e004fd1cc35d5.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 330, + 278, + 351 + ], + "lines": [ + { + "bbox": [ + 46, + 330, + 278, + 351 + ], + "spans": [ + { + "bbox": [ + 46, + 330, + 278, + 351 + ], + "type": "text", + "content": "Table 4. Effect of position of side-interpolater. MDT-S/2 models contain 12 blocks and are trained with 600k iterations." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 370, + 278, + 393 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 370, + 278, + 393 + ], + "spans": [ + { + "bbox": [ + 46, + 370, + 278, + 393 + ], + "type": "text", + "content": "observe the model has saturated FID scores when continuing training." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 409, + 279, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 409, + 279, + 536 + ], + "spans": [ + { + "bbox": [ + 45, + 409, + 279, + 536 + ], + "type": "text", + "content": "Convergence speed. Fig. 1 compares the performance of the DiT/S-2 baseline and MDT/S-2 under different training steps and training time on " + }, + { + "bbox": [ + 45, + 409, + 279, + 536 + ], + "type": "inline_equation", + "content": "8 \\times \\mathrm{A}100" + }, + { + "bbox": [ + 45, + 409, + 279, + 536 + ], + "type": "text", + "content": " GPUs. Because of the stronger contextual learning ability, MDT achieves better performance with faster generation learning speed. MDT enjoys about " + }, + { + "bbox": [ + 45, + 409, + 279, + 536 + ], + "type": "inline_equation", + "content": "3 \\times" + }, + { + "bbox": [ + 45, + 409, + 279, + 536 + ], + "type": "text", + "content": " faster learning speed in terms of both training steps and training time. For example, MDT-S/2 trained with about 33 hours (400k steps) achieves superior performance than DiT-S/2 trained with about 100 hours (1500k steps). This reveals that contextual learning is vital for faster generation learning of diffusion models." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 544, + 108, + 555 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 544, + 108, + 555 + ], + "spans": [ + { + "bbox": [ + 46, + 544, + 108, + 555 + ], + "type": "text", + "content": "4.3. Ablation" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 563, + 278, + 596 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 563, + 278, + 596 + ], + "spans": [ + { + "bbox": [ + 46, + 563, + 278, + 596 + ], + "type": "text", + "content": "In this part, we conduct ablation to verify the designs in MDT. We report the results of MDT-S/2 model and use FID-50k as the evaluation metric unless otherwise stated." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 45, + 612, + 279, + 729 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 612, + 279, + 729 + ], + "spans": [ + { + "bbox": [ + 45, + 612, + 279, + 729 + ], + "type": "text", + "content": "Masking ratio. The masking ratio determines the number of input patches that can be processed during training. We give the comparison of using different masking ratios in Tab. 3. The best masking ratio for MDT-S/2 is " + }, + { + "bbox": [ + 45, + 612, + 279, + 729 + ], + "type": "inline_equation", + "content": "30\\%" + }, + { + "bbox": [ + 45, + 612, + 279, + 729 + ], + "type": "text", + "content": ", which is quite different from the masking ratio used for recognition models, e.g. " + }, + { + "bbox": [ + 45, + 612, + 279, + 729 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 45, + 612, + 279, + 729 + ], + "type": "text", + "content": " masking ratio in MAE [19]. We assume that the image generation requires learning more details from more patches for high-quality synthesis, while recognition models only need the most essential patches to infer semantics." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 297, + 106, + 530, + 256 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 106, + 530, + 256 + ], + "spans": [ + { + "bbox": [ + 297, + 106, + 530, + 256 + ], + "type": "text", + "content": "Side-interpolater position. To meet the high-quality image generation requirements of the diffusion model, the side-interpolater is placed in the middle of the network instead of the end of the network in recognition models [3, 19]. Tab. 4, presents the comparison of placing the side-interpolater at different positions of the MDT-S model with 12 blocks. The results show that placing the side-interpolater before the last two blocks achieves the best FID score, whereas placing it at the end of the network like recognition models impairs the performance. Placing the side-interpolater at the early stages of the network also harm the performance, indicating the mask latent modeling is beneficial to most stages in the diffusion models." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 297, + 273, + 531, + 458 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 273, + 531, + 458 + ], + "spans": [ + { + "bbox": [ + 297, + 273, + 531, + 458 + ], + "type": "text", + "content": "Asymmetric vs. Symmetric architecture in masking. Unlike the masked generation works [6, 7], e.g., MaskGIT, that utilize the masking scheme to generate images, MDT focuses on improving diffusion models with contextual learning ability via the masking latent modeling. Therefore, we use an asymmetric architecture to only process the unmasked tokens in the diffusion model encoder. We compare the asymmetric architecture in MDT and the symmetrical architecture [7] that processes full input with masked tokens replaced by a learnable mask token. As shown in Tab. 5a, the asymmetric architecture in MDT has an FID of 50.26, outperforming the FID of 51.56 achieved by the symmetric architecture. The asymmetric architecture further reduces the training cost and allows the diffusion model to focus on learning contextual information instead of reconstructing masked tokens." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 297, + 475, + 530, + 557 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 475, + 530, + 557 + ], + "spans": [ + { + "bbox": [ + 297, + 475, + 530, + 557 + ], + "type": "text", + "content": "Effect of side-interpolater. The side-interpolater in MDT predicts the masked tokens, allowing the diffusion model to learn more semantics and maintain consistency in decoder inputs during training and inference. We compare the performance with/without the side-interpolater in Tab. 5b, and observe a gain of 1.34 in FID when using the side-interpolater, proving its effectiveness." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 297, + 574, + 530, + 655 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 574, + 530, + 655 + ], + "spans": [ + { + "bbox": [ + 297, + 574, + 530, + 655 + ], + "type": "text", + "content": "Masked shortcut in side-interpolater. The masked shortcut ensures that the side-interpolater only predicts the masked tokens from unmasked ones. Tab. 5c shows that using the masked shortcut enhances the FID from 50.91 to 50.26, indicating that restricting side-interpolater to only predict masked tokens helps the diffusion model achieve stronger performance." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 297, + 671, + 530, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 671, + 530, + 730 + ], + "spans": [ + { + "bbox": [ + 297, + 671, + 530, + 730 + ], + "type": "text", + "content": "Full and masked latent tokens. In MDT, both the full and masked latent embeddings are fed into the diffusion model during training. In comparison, we give the results trained by only using full/masked latent embeddings as shown in Tab. 5d, where the computational cost is aligned for" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "spans": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "type": "text", + "content": "23170" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 54, + 113, + 208, + 159 + ], + "blocks": [ + { + "bbox": [ + 54, + 113, + 208, + 159 + ], + "lines": [ + { + "bbox": [ + 54, + 113, + 208, + 159 + ], + "spans": [ + { + "bbox": [ + 54, + 113, + 208, + 159 + ], + "type": "table", + "html": "
Asymmetric stru.FID-50k↓
×51.56
✓50.26
", + "image_path": "79fe9cfa5887795e4b6d47f67abee62e944bd774666e53caeb19c98b4d3defb0.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 211, + 113, + 367, + 159 + ], + "blocks": [ + { + "bbox": [ + 61, + 160, + 198, + 170 + ], + "lines": [ + { + "bbox": [ + 61, + 160, + 198, + 170 + ], + "spans": [ + { + "bbox": [ + 61, + 160, + 198, + 170 + ], + "type": "text", + "content": "(a) Effect of asymmetric masking structure." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 211, + 113, + 367, + 159 + ], + "lines": [ + { + "bbox": [ + 211, + 113, + 367, + 159 + ], + "spans": [ + { + "bbox": [ + 211, + 113, + 367, + 159 + ], + "type": "table", + "html": "
Side-interpolaterFID-50k↓
×51.60
✓50.26
", + "image_path": "6de7d39a42b4a0b7e05db4524f2c0b14242db0caf917cd1f570134653385ad57.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 370, + 113, + 525, + 159 + ], + "blocks": [ + { + "bbox": [ + 241, + 160, + 335, + 170 + ], + "lines": [ + { + "bbox": [ + 241, + 160, + 335, + 170 + ], + "spans": [ + { + "bbox": [ + 241, + 160, + 335, + 170 + ], + "type": "text", + "content": "(b) Effect of side-interpolater." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 370, + 113, + 525, + 159 + ], + "lines": [ + { + "bbox": [ + 370, + 113, + 525, + 159 + ], + "spans": [ + { + "bbox": [ + 370, + 113, + 525, + 159 + ], + "type": "table", + "html": "
Masked shortcutFID-50k↓
×50.91
✓50.26
", + "image_path": "e6e8acfd866911f0cd7016f68d8658c0a8e531e62e969fdb93d07440dafe71e2.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 54, + 181, + 205, + 235 + ], + "blocks": [ + { + "bbox": [ + 400, + 160, + 493, + 170 + ], + "lines": [ + { + "bbox": [ + 400, + 160, + 493, + 170 + ], + "spans": [ + { + "bbox": [ + 400, + 160, + 493, + 170 + ], + "type": "text", + "content": "(c) Effect of masked shortcut." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 54, + 181, + 205, + 235 + ], + "lines": [ + { + "bbox": [ + 54, + 181, + 205, + 235 + ], + "spans": [ + { + "bbox": [ + 54, + 181, + 205, + 235 + ], + "type": "table", + "html": "
Latent typeFID-50k↓
Full+Masked50.26
Full52.30
Masked76.63
", + "image_path": "4889b9365d617c81a47424df6cf2518342650dd355531287726f354852ed8916.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 211, + 181, + 366, + 235 + ], + "blocks": [ + { + "bbox": [ + 54, + 238, + 202, + 248 + ], + "lines": [ + { + "bbox": [ + 54, + 238, + 202, + 248 + ], + "spans": [ + { + "bbox": [ + 54, + 238, + 202, + 248 + ], + "type": "text", + "content": "(d) Using full/masked latent under aligned cost." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 211, + 181, + 366, + 235 + ], + "lines": [ + { + "bbox": [ + 211, + 181, + 366, + 235 + ], + "spans": [ + { + "bbox": [ + 211, + 181, + 366, + 235 + ], + "type": "table", + "html": "
Sup. partsFID-50k↓
All50.26
Masked58.35
", + "image_path": "5f2c0f0357cf74171612d98877129425ec4fdad33ff0ce72c3c7854d4f0afd7a.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 370, + 181, + 525, + 235 + ], + "blocks": [ + { + "bbox": [ + 239, + 238, + 335, + 248 + ], + "lines": [ + { + "bbox": [ + 239, + 238, + 335, + 248 + ], + "spans": [ + { + "bbox": [ + 239, + 238, + 335, + 248 + ], + "type": "text", + "content": "(e) Supervision on token parts." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 370, + 181, + 525, + 235 + ], + "lines": [ + { + "bbox": [ + 370, + 181, + 525, + 235 + ], + "spans": [ + { + "bbox": [ + 370, + 181, + 525, + 235 + ], + "type": "table", + "html": "
NumberFID-50k↓
150.26
251.77
351.96
", + "image_path": "7440d3cbc06bb9f0cfadeb858fa1eedd6165ef4a7044779e52be8096afeb6f32.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 54, + 257, + 207, + 302 + ], + "blocks": [ + { + "bbox": [ + 382, + 238, + 512, + 248 + ], + "lines": [ + { + "bbox": [ + 382, + 238, + 512, + 248 + ], + "spans": [ + { + "bbox": [ + 382, + 238, + 512, + 248 + ], + "type": "text", + "content": "(f) Number of blocks in side-interpolator." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 54, + 257, + 207, + 302 + ], + "lines": [ + { + "bbox": [ + 54, + 257, + 207, + 302 + ], + "spans": [ + { + "bbox": [ + 54, + 257, + 207, + 302 + ], + "type": "table", + "html": "
IS Pos. embed.FID-50k↓
×51.58
✓50.26
", + "image_path": "0c025f94c2129809bc3228355aa4e7033491e4c88dd20ddb3841b603c32af2d9.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_body" + } + ], + "index": 12 + }, + { + "type": "table", + "bbox": [ + 211, + 257, + 365, + 302 + ], + "blocks": [ + { + "bbox": [ + 63, + 304, + 194, + 314 + ], + "lines": [ + { + "bbox": [ + 63, + 304, + 194, + 314 + ], + "spans": [ + { + "bbox": [ + 63, + 304, + 194, + 314 + ], + "type": "text", + "content": "(g) Effect of positional embeddings in SI." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 211, + 257, + 365, + 302 + ], + "lines": [ + { + "bbox": [ + 211, + 257, + 365, + 302 + ], + "spans": [ + { + "bbox": [ + 211, + 257, + 365, + 302 + ], + "type": "table", + "html": "
Learnable pos.FID-50k↓
×50.80
✓50.26
", + "image_path": "8683b7992fc4a6dfa68bdddb19cd2c8dcd06ae418c6ddadf73d73c9dc85d1e20.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "table_body" + } + ], + "index": 14 + }, + { + "type": "table", + "bbox": [ + 370, + 257, + 525, + 302 + ], + "blocks": [ + { + "bbox": [ + 215, + 304, + 359, + 314 + ], + "lines": [ + { + "bbox": [ + 215, + 304, + 359, + 314 + ], + "spans": [ + { + "bbox": [ + 215, + 304, + 359, + 314 + ], + "type": "text", + "content": "(h) Effect of learnable positional embeddings." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 370, + 257, + 525, + 302 + ], + "lines": [ + { + "bbox": [ + 370, + 257, + 525, + 302 + ], + "spans": [ + { + "bbox": [ + 370, + 257, + 525, + 302 + ], + "type": "table", + "html": "
Relative pos. biasFID-50k↓
×53.56
✓50.26
", + "image_path": "90190e2b64420a83b5f922c0fbba435311894e80ba63b3de1ccf80ee81a17471.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "table_body" + } + ], + "index": 16 + }, + { + "bbox": [ + 390, + 304, + 502, + 314 + ], + "lines": [ + { + "bbox": [ + 390, + 304, + 502, + 314 + ], + "spans": [ + { + "bbox": [ + 390, + 304, + 502, + 314 + ], + "type": "text", + "content": "(i) Effect of relative positional bias." + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 153, + 317, + 422, + 327 + ], + "lines": [ + { + "bbox": [ + 153, + 317, + 422, + 327 + ], + "spans": [ + { + "bbox": [ + 153, + 317, + 422, + 327 + ], + "type": "text", + "content": "Table 5. Ablation study on MDT-S/2. Models are trained for 600k iterations." + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 45, + 347, + 279, + 417 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 347, + 279, + 417 + ], + "spans": [ + { + "bbox": [ + 45, + 347, + 279, + 417 + ], + "type": "text", + "content": "fair comparisons. Trained with both full and masked latent leads to clear gain over two competitors. While using only the masked latent embeddings results in slow convergence, which we attribute to the training/inference inconsistency as the inference in MDT is a diffusion process instead of the masked reconstruction process." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 45, + 431, + 279, + 537 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 431, + 279, + 537 + ], + "spans": [ + { + "bbox": [ + 45, + 431, + 279, + 537 + ], + "type": "text", + "content": "Loss on all tokens. By default, we calculate the loss on both masked and unmasked latent embeddings. In comparison, mask modeling for recognition models commonly calculates loss on masked tokens [3, 19]. Tab. 5e shows that calculating the loss on all tokens is much better than on masked tokens. We assume that this is because generative models require stronger consistency among patches than recognition models do, since details are vital for high-quality image synthesis." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 45, + 551, + 279, + 633 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 551, + 279, + 633 + ], + "spans": [ + { + "bbox": [ + 45, + 551, + 279, + 633 + ], + "type": "text", + "content": "Block number in side-interpolater. We compare the performance of different numbers of blocks in the side-interpolater in Tab. 5f. The default setting of 1 block achieves the best performance, and the FID worsens with an increase in block number. This result is consistent with our motivation that side-interpolater should not learn too much information other than interpolating the masked representations." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 45, + 648, + 280, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 648, + 280, + 730 + ], + "spans": [ + { + "bbox": [ + 45, + 648, + 280, + 730 + ], + "type": "text", + "content": "Positional-aware enhancement. To further release the potential of mask latent modeling, we enhance the DiT baseline with stronger positional awareness ability, i.e. learnable positional embeddings and the relative positional bias in basic blocks. Tab. 5g shows the positional embeddings in side-interpolator improves the FID from 51.58 to 50.26, indicating the positional embedding is vital for the side-interpolator." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 296, + 347, + 531, + 464 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 347, + 531, + 464 + ], + "spans": [ + { + "bbox": [ + 296, + 347, + 531, + 464 + ], + "type": "text", + "content": "Also, enables the training of positional embeddings brings the gain in FID as revealed in Tab. 5h. In Tab. 5i, the relative positional bias in the basic blocks significantly improves the FID from 53.56 to 50.26, showing the relative positional modeling ability is essential for diffusion models to obtain the contextual representation ability and generate high-quality images. Therefore, the positional awareness ability in diffusion model structure is required to accompany the masked latent modeling, playing a key role in improving performance." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 297, + 472, + 368, + 484 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 472, + 368, + 484 + ], + "spans": [ + { + "bbox": [ + 297, + 472, + 368, + 484 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 296, + 492, + 531, + 643 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 492, + 531, + 643 + ], + "spans": [ + { + "bbox": [ + 296, + 492, + 531, + 643 + ], + "type": "text", + "content": "This work proposes a masked diffusion transformer to enhance the contextual representation and improve the relation learning among image semantics for DPMs. We introduce an effective mask latent modeling scheme into DPMs and also accordingly designs an asymmetric masking diffusion transformer structure. Experiments show that our masked diffusion transformer enjoys higher performance on image synthesis and largely improves the learning progress during training, achieving the new SOTA for image synthesis on the ImageNet dataset. We hope our initial exploration of contextual learning for generative modeling can facilitate more work on unifying the representation learning for recognition and generative models." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 297, + 652, + 395, + 665 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 652, + 395, + 665 + ], + "spans": [ + { + "bbox": [ + 297, + 652, + 395, + 665 + ], + "type": "text", + "content": "Acknowledgement." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 296, + 671, + 531, + 730 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 671, + 531, + 730 + ], + "spans": [ + { + "bbox": [ + 296, + 671, + 531, + 730 + ], + "type": "text", + "content": "This research was supported by the NSFC (NO. 62225604) and the Fundamental Research Funds for the Central Universities (Nankai University, 070-63233089). The Supercomputing Center of Nankai University supports computation." + } + ] + } + ], + "index": 27 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 276, + 747, + 299, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 276, + 747, + 299, + 756 + ], + "spans": [ + { + "bbox": [ + 276, + 747, + 299, + 756 + ], + "type": "text", + "content": "23171" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 105, + 102, + 117 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 105, + 102, + 117 + ], + "spans": [ + { + "bbox": [ + 47, + 105, + 102, + 117 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 125, + 280, + 730 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 51, + 125, + 279, + 158 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 125, + 279, + 158 + ], + "spans": [ + { + "bbox": [ + 51, + 125, + 279, + 158 + ], + "type": "text", + "content": "[1] Fan Bao, Chongxuan Li, Yue Cao, and Jun Zhu. All are worth words: a vit backbone for score-based diffusion models. arXiv preprint arXiv:2209.12152, 2022. 3, 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 51, + 159, + 280, + 202 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 159, + 280, + 202 + ], + "spans": [ + { + "bbox": [ + 51, + 159, + 280, + 202 + ], + "type": "text", + "content": "[2] Fan Bao, Chongxuan Li, Jiacheng Sun, Jun Zhu, and Bo Zhang. Estimating the optimal covariance with imperfect mean in diffusion probabilistic models. In Int. Mach. Learn., 2022. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 51, + 204, + 280, + 235 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 204, + 280, + 235 + ], + "spans": [ + { + "bbox": [ + 51, + 204, + 280, + 235 + ], + "type": "text", + "content": "[3] Hangbo Bao, Li Dong, and Furu Wei. Beit: Bert pre-training of image transformers. Int. Conf. Learn. Represent., 2022. 3, 4, 7, 8" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 51, + 238, + 280, + 271 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 238, + 280, + 271 + ], + "spans": [ + { + "bbox": [ + 51, + 238, + 280, + 271 + ], + "type": "text", + "content": "[4] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale gan training for high fidelity natural image synthesis. Int. Conf. Learn. Represent., 2019. 1, 2, 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 51, + 272, + 280, + 325 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 272, + 280, + 325 + ], + "spans": [ + { + "bbox": [ + 51, + 272, + 280, + 325 + ], + "type": "text", + "content": "[5] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, et al. Language models are few-shot learners. Adv. Neural Inform. Process. Syst., 33:1877-1901, 2020. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 51, + 327, + 280, + 381 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 327, + 280, + 381 + ], + "spans": [ + { + "bbox": [ + 51, + 327, + 280, + 381 + ], + "type": "text", + "content": "[6] Huiwen Chang, Han Zhang, Jarred Barber, AJ Maschinot, Jose Lezama, Lu Jiang, Ming-Hsuan Yang, Kevin Murphy, William T Freeman, Michael Rubinstein, et al. Muse: Text-to-image generation via masked generative transformers. arXiv preprint arXiv:2301.00704, 2023. 3, 4, 7" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 51, + 383, + 280, + 425 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 383, + 280, + 425 + ], + "spans": [ + { + "bbox": [ + 51, + 383, + 280, + 425 + ], + "type": "text", + "content": "[7] Huiwen Chang, Han Zhang, Lu Jiang, Ce Liu, and William T Freeman. Maskgit: Masked generative image transformer. In IEEE Conf. Comput. Vis. Pattern Recog., pages 11315-11325, 2022. 3, 4, 6, 7" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 51, + 427, + 280, + 469 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 427, + 280, + 469 + ], + "spans": [ + { + "bbox": [ + 51, + 427, + 280, + 469 + ], + "type": "text", + "content": "[8] Gong Cheng, Ruimin Li, Chunbo Lang, and Junwei Han. Task-wise attention guided part complementary learning for few-shot image classification. Science China Information Sciences, 64:1-14, 2021. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 51, + 472, + 280, + 504 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 51, + 472, + 280, + 504 + ], + "spans": [ + { + "bbox": [ + 51, + 472, + 280, + 504 + ], + "type": "text", + "content": "[9] J. Deng, W. Dong, R. Socher, L.-J. Li, K. Li, and L. Fei-Fei. Imagenet: A large-scale hierarchical image database. In IEEE Conf. Comput. Vis. Pattern Recog., 2009. 1, 6" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 506, + 280, + 538 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 506, + 280, + 538 + ], + "spans": [ + { + "bbox": [ + 47, + 506, + 280, + 538 + ], + "type": "text", + "content": "[10] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. NAACL, 2019. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 540, + 280, + 571 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 540, + 280, + 571 + ], + "spans": [ + { + "bbox": [ + 47, + 540, + 280, + 571 + ], + "type": "text", + "content": "[11] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Adv. Neural Inform. Process. Syst., 34:8780-8794, 2021. 1, 2, 3, 6" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 574, + 280, + 606 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 574, + 280, + 606 + ], + "spans": [ + { + "bbox": [ + 47, + 574, + 280, + 606 + ], + "type": "text", + "content": "[12] Tim Dockhorn, Arash Vahdat, and Karsten Kreis. Score-based generative modeling with critically-damped Langevin diffusion. In Int. Conf. Learn. Represent., 2022. 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 47, + 608, + 280, + 650 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 608, + 280, + 650 + ], + "spans": [ + { + "bbox": [ + 47, + 608, + 280, + 650 + ], + "type": "text", + "content": "[13] Patrick Esser, Robin Rombach, and Bjorn Ommer. Taming transformers for high-resolution image synthesis. In IEEE Conf. Comput. Vis. Pattern Recog., pages 12873-12883, 2021. 6" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 47, + 653, + 280, + 694 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 653, + 280, + 694 + ], + "spans": [ + { + "bbox": [ + 47, + 653, + 280, + 694 + ], + "type": "text", + "content": "[14] Shanghua Gao, Zhong-Yu Li, Ming-Hsuan Yang, Ming-Ming Cheng, Junwei Han, and Philip Torr. Large-scale unsupervised semantic segmentation. IEEE Trans. Pattern Anal. Mach. Intell., 2022. 1" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 47, + 697, + 280, + 730 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 697, + 280, + 730 + ], + "spans": [ + { + "bbox": [ + 47, + 697, + 280, + 730 + ], + "type": "text", + "content": "[15] Shanghua Gao, Pan Zhou, Ming-Ming Cheng, and Shuicheng Yan. Towards sustainable self-supervised learning. arXiv preprint arXiv:2210.11016, 2022. 3" + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 299, + 106, + 531, + 730 + ], + "type": "list", + "angle": 0, + "index": 32, + "blocks": [ + { + "bbox": [ + 299, + 106, + 531, + 159 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 106, + 531, + 159 + ], + "spans": [ + { + "bbox": [ + 299, + 106, + 531, + 159 + ], + "type": "text", + "content": "[16] Shuyang Gu, Dong Chen, Jianmin Bao, Fang Wen, Bo Zhang, Dongdong Chen, Lu Yuan, and Baining Guo. Vector quantized diffusion model for text-to-image synthesis. In IEEE Conf. Comput. Vis. Pattern Recog., pages 10696-10706, 2022. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 299, + 161, + 531, + 203 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 161, + 531, + 203 + ], + "spans": [ + { + "bbox": [ + 299, + 161, + 531, + 203 + ], + "type": "text", + "content": "[17] Yuchao Gu, Xintao Wang, Yixiao Ge, Ying Shan, Xiaohu Qie, and Mike Zheng Shou. Rethinking the objectives of vector-quantized tokenizers for image synthesis. arXiv preprint arXiv:2212.03185, 2022. 1" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 299, + 205, + 531, + 258 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 205, + 531, + 258 + ], + "spans": [ + { + "bbox": [ + 299, + 205, + 531, + 258 + ], + "type": "text", + "content": "[18] Meng-Hao Guo, Tian-Xing Xu, Jiang-Jiang Liu, Zheng-Ning Liu, Peng-Tao Jiang, Tai-Jiang Mu, Song-Hai Zhang, Ralph R. Martin, Ming-Ming Cheng, and Shi-Min Hu. Attention mechanisms in computer vision: A survey. Computational Visual Media, 8(3):331-368, 2022. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 299, + 260, + 531, + 301 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 260, + 531, + 301 + ], + "spans": [ + { + "bbox": [ + 299, + 260, + 531, + 301 + ], + "type": "text", + "content": "[19] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollar, and Ross Girshick. Masked autoencoders are scalable vision learners. In IEEE Conf. Comput. Vis. Pattern Recog., pages 16000-16009, 2022. 3, 7, 8" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 299, + 303, + 531, + 346 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 303, + 531, + 346 + ], + "spans": [ + { + "bbox": [ + 299, + 303, + 531, + 346 + ], + "type": "text", + "content": "[20] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Adv. Neural Inform. Process. Syst., 30, 2017. 6" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 299, + 346, + 531, + 378 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 346, + 531, + 378 + ], + "spans": [ + { + "bbox": [ + 299, + 346, + 531, + 378 + ], + "type": "text", + "content": "[21] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Adv. Neural Inform. Process. Syst., 33:6840-6851, 2020. 1, 2, 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 299, + 380, + 531, + 422 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 380, + 531, + 422 + ], + "spans": [ + { + "bbox": [ + 299, + 380, + 531, + 422 + ], + "type": "text", + "content": "[22] Jonathan Ho, Chitwan Sahara, William Chan, David J Fleet, Mohammad Norouzi, and Tim Salimans. Cascaded diffusion models for high fidelity image generation. J. Mach. Learn. Res., 23(47):1-33, 2022. 2, 6" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 299, + 424, + 531, + 445 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 424, + 531, + 445 + ], + "spans": [ + { + "bbox": [ + 299, + 424, + 531, + 445 + ], + "type": "text", + "content": "[23] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. NeurIPS Workshop, 2021. 2, 6" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 299, + 446, + 531, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 446, + 531, + 487 + ], + "spans": [ + { + "bbox": [ + 299, + 446, + 531, + 487 + ], + "type": "text", + "content": "[24] Myeonghun Jeong, Hyeongju Kim, Sung Jun Cheon, Byoung Jin Choi, and Nam Soo Kim. Diff-tps: A denoising diffusion model for text-to-speech. In INTERSPEECH, 2021. 1" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 299, + 490, + 531, + 532 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 490, + 531, + 532 + ], + "spans": [ + { + "bbox": [ + 299, + 490, + 531, + 532 + ], + "type": "text", + "content": "[25] Ge-Peng Ji, Mingchen Zhuge, Dehong Gao, Deng-Ping Fan, Christos Sakaridis, and Luc Van Gool. Masked vision-language transformer in fashion. Machine Intelligence Research, 20(3):421-434, 2023. 3" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 299, + 533, + 531, + 565 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 533, + 531, + 565 + ], + "spans": [ + { + "bbox": [ + 299, + 533, + 531, + 565 + ], + "type": "text", + "content": "[26] Tero Karras, Miika Aittala, Timo Aila, and Samuli Laine. Elucidating the design space of diffusion-based generative models. In Adv. Neural Inform. Process. Syst., 2022. 2" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 299, + 566, + 531, + 608 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 566, + 531, + 608 + ], + "spans": [ + { + "bbox": [ + 299, + 566, + 531, + 608 + ], + "type": "text", + "content": "[27] Dongjun Kim, Seungjae Shin, Kyungwoo Song, Wanmo Kang, and Il-Chul Moon. Soft truncation: A universal training technique of score-based diffusion model for high precision score estimation. In Int. Mach. Learn., 2022. 2" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 299, + 610, + 531, + 641 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 610, + 531, + 641 + ], + "spans": [ + { + "bbox": [ + 299, + 610, + 531, + 641 + ], + "type": "text", + "content": "[28] Diederik Kingma, Tim Salimans, Ben Poole, and Jonathan Ho. Variational diffusion models. Adv. Neural Inform. Process. Syst., 34:21696-21707, 2021. 2" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 299, + 643, + 531, + 685 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 643, + 531, + 685 + ], + "spans": [ + { + "bbox": [ + 299, + 643, + 531, + 685 + ], + "type": "text", + "content": "[29] Tuomas Kynkänniemi, Tero Karras, Samuli Laine, Jaakko Lehtinen, and Timo Aila. Improved precision and recall metric for assessing generative models. Adv. Neural Inform. Process. Syst., 32, 2019. 6" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 299, + 687, + 531, + 730 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 687, + 531, + 730 + ], + "spans": [ + { + "bbox": [ + 299, + 687, + 531, + 730 + ], + "type": "text", + "content": "[30] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Int. Conf. Comput. Vis., pages 10012-10022, 2021. 5" + } + ] + } + ], + "index": 31 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "spans": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "type": "text", + "content": "23172" + } + ] + } + ], + "index": 33 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 106, + 280, + 729 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 47, + 106, + 279, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 106, + 279, + 128 + ], + "spans": [ + { + "bbox": [ + 47, + 106, + 279, + 128 + ], + "type": "text", + "content": "[31] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. Int. Conf. Learn. Represent., 2019. 6" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 129, + 279, + 172 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 129, + 279, + 172 + ], + "spans": [ + { + "bbox": [ + 47, + 129, + 279, + 172 + ], + "type": "text", + "content": "[32] Cheng Lu, Yuhao Zhou, Fan Bao, Jianfei Chen, Chongxuan Li, and Jun Zhu. Dpm-solver: A fast ode solver for diffusion probabilistic model sampling in around 10 steps. Adv. Neural Inform. Process. Syst., 2022. 1, 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 173, + 280, + 204 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 173, + 280, + 204 + ], + "spans": [ + { + "bbox": [ + 47, + 173, + 280, + 204 + ], + "type": "text", + "content": "[33] Charlie Nash, Jacob Menick, Sander Dieleman, and Peter W Battaglia. Generating images with sparse representations. Int. Mach. Learn., 2021. 6" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 206, + 280, + 238 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 206, + 280, + 238 + ], + "spans": [ + { + "bbox": [ + 47, + 206, + 280, + 238 + ], + "type": "text", + "content": "[34] Alexander Quinn Nichol and Prafulla Dhariwal. Improved denoising diffusion probabilistic models. In Int. Mach. Learn., pages 8162-8171. PMLR, 2021. 2, 3, 5, 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 239, + 280, + 271 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 239, + 280, + 271 + ], + "spans": [ + { + "bbox": [ + 47, + 239, + 280, + 271 + ], + "type": "text", + "content": "[35] William Peebles and Saining Xie. Scalable diffusion models with transformers. arXiv preprint arXiv:2212.09748, 2022. 1, 2, 3, 4, 5, 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 271, + 280, + 303 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 271, + 280, + 303 + ], + "spans": [ + { + "bbox": [ + 47, + 271, + 280, + 303 + ], + "type": "text", + "content": "[36] Alec Radford, Karthik Narasimhan, Tim Salimans, Ilya Sutskever, et al. Improving language understanding by generative pre-training, 2018. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 304, + 280, + 336 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 304, + 280, + 336 + ], + "spans": [ + { + "bbox": [ + 47, + 304, + 280, + 336 + ], + "type": "text", + "content": "[37] Ali Razavi, Aaron Van den Oord, and Oriol Vinyals. Generating diverse high-fidelity images with vq-vae-2. Adv. Neural Inform. Process. Syst., 32, 2019. 1, 6" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 337, + 280, + 390 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 337, + 280, + 390 + ], + "spans": [ + { + "bbox": [ + 47, + 337, + 280, + 390 + ], + "type": "text", + "content": "[38] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In IEEE Conf. Comput. Vis. Pattern Recog., pages 10684-10695, 2022. 1, 2, 3, 4, 5, 6" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 392, + 280, + 434 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 392, + 280, + 434 + ], + "spans": [ + { + "bbox": [ + 47, + 392, + 280, + 434 + ], + "type": "text", + "content": "[39] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In Int. Conf. Med Image Comput Comput Assist Interv., pages 234-241. Springer, 2015. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 436, + 280, + 477 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 436, + 280, + 477 + ], + "spans": [ + { + "bbox": [ + 47, + 436, + 280, + 477 + ], + "type": "text", + "content": "[40] Tim Salimans, Ian Goodfellow, Wojciech Zaremba, Vicki Cheung, Alec Radford, and Xi Chen. Improved techniques for training gans. Adv. Neural Inform. Process. Syst., 29, 2016. 6" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 479, + 280, + 511 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 479, + 280, + 511 + ], + "spans": [ + { + "bbox": [ + 47, + 479, + 280, + 511 + ], + "type": "text", + "content": "[41] Tim Salimans and Jonathan Ho. Progressive distillation for fast sampling of diffusion models. Int. Conf. Learn. Represent., 2022. 1, 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 511, + 280, + 554 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 511, + 280, + 554 + ], + "spans": [ + { + "bbox": [ + 47, + 511, + 280, + 554 + ], + "type": "text", + "content": "[42] Tim Salimans, Andrej Karpathy, Xi Chen, and Diederik P Kingma. PixelCNN++: Improving the pixelCNN with discretized logistic mixture likelihood and other modifications. In Int. Conf. Learn. Represent., 2017. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 555, + 280, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 555, + 280, + 588 + ], + "spans": [ + { + "bbox": [ + 47, + 555, + 280, + 588 + ], + "type": "text", + "content": "[43] Axel Sauer, Katja Schwarz, and Andreas Geiger. Stylegan-xl: Scaling stylegan to large diverse datasets. In ACM SIGGRAPH 2022 conference proceedings, pages 1-10, 2022. 6" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 47, + 589, + 280, + 651 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 589, + 280, + 651 + ], + "spans": [ + { + "bbox": [ + 47, + 589, + 280, + 651 + ], + "type": "text", + "content": "[44] Christoph Schuhmann, Romain Beaumont, Richard Vencu, Cade Gordon, Ross Wightman, Mehdi Cherti, Theo Coombes, Aarush Katta, Clayton Mullis, Mitchell Wortsman, et al. Laion-5b: An open large-scale dataset for training next generation image-text models. Adv. Neural Inform. Process. Syst., 2022. 1" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 47, + 653, + 280, + 696 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 653, + 280, + 696 + ], + "spans": [ + { + "bbox": [ + 47, + 653, + 280, + 696 + ], + "type": "text", + "content": "[45] Jascha Sohl-Dickstein, Eric Weiss, Niru Maheswaranathan, and Surya Ganguli. Deep unsupervised learning using nonequilibrium thermodynamics. In Int. Mach. Learn., pages 2256-2265. PMLR, 2015. 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 47, + 697, + 280, + 729 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 697, + 280, + 729 + ], + "spans": [ + { + "bbox": [ + 47, + 697, + 280, + 729 + ], + "type": "text", + "content": "[46] Jiaming Song, Chenlin Meng, and Stefano Ermon. Denoising diffusion implicit models. In Int. Conf. Learn. Represent., 2021. 2, 3" + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 299, + 106, + 531, + 544 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 299, + 106, + 531, + 138 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 106, + 531, + 138 + ], + "spans": [ + { + "bbox": [ + 299, + 106, + 531, + 138 + ], + "type": "text", + "content": "[47] Yang Song, Conor Durkan, Iain Murray, and Stefano Ermon. Maximum likelihood training of score-based diffusion models. Adv. Neural Inform. Process. Syst., 34:1415-1428, 2021. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 299, + 139, + 531, + 171 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 139, + 531, + 171 + ], + "spans": [ + { + "bbox": [ + 299, + 139, + 531, + 171 + ], + "type": "text", + "content": "[48] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. Adv. Neural Inform. Process. Syst., 32, 2019. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 299, + 172, + 531, + 204 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 172, + 531, + 204 + ], + "spans": [ + { + "bbox": [ + 299, + 172, + 531, + 204 + ], + "type": "text", + "content": "[49] Yang Song and Stefano Ermon. Improved techniques for training score-based generative models. Adv. Neural Inform. Process. Syst., 33:12438-12448, 2020. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 299, + 206, + 531, + 248 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 206, + 531, + 248 + ], + "spans": [ + { + "bbox": [ + 299, + 206, + 531, + 248 + ], + "type": "text", + "content": "[50] Yang Song, Jascha Sohl-Dickstein, Diederik P Kingma, Abhishek Kumar, Stefano Ermon, and Ben Poole. Score-based generative modeling through stochastic differential equations. Int. Conf. Learn. Represent., 2021. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 299, + 249, + 531, + 281 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 249, + 531, + 281 + ], + "spans": [ + { + "bbox": [ + 299, + 249, + 531, + 281 + ], + "type": "text", + "content": "[51] Arash Vahdat, Karsten Kreis, and Jan Kautz. Score-based generative modeling in latent space. In Adv. Neural Inform. Process. Syst., 2021. 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 299, + 281, + 531, + 325 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 281, + 531, + 325 + ], + "spans": [ + { + "bbox": [ + 299, + 281, + 531, + 325 + ], + "type": "text", + "content": "[52] Aaron Van den Oord, Nal Kalchbrenner, Lasse Espeholt, Oriol Vinyals, Alex Graves, et al. Conditional image generation with pixelCNN decoders. Adv. Neural Inform. Process. Syst., 29, 2016. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 299, + 325, + 531, + 367 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 325, + 531, + 367 + ], + "spans": [ + { + "bbox": [ + 299, + 325, + 531, + 367 + ], + "type": "text", + "content": "[53] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Adv. Neural Inform. Process. Syst., 30, 2017. 5" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 299, + 368, + 531, + 402 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 368, + 531, + 402 + ], + "spans": [ + { + "bbox": [ + 299, + 368, + 531, + 402 + ], + "type": "text", + "content": "[54] Yan Wu, Jeff Donahue, David Balduzzi, Karen Simonyan, and Timothy Lillicrap. Logan: Latent optimisation for generative adversarial networks. Int. Conf. Learn. Represent., 2020. 1" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 299, + 403, + 531, + 424 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 403, + 531, + 424 + ], + "spans": [ + { + "bbox": [ + 299, + 403, + 531, + 424 + ], + "type": "text", + "content": "[55] Yuxin Wu and Kaiming He. Group normalization. In Eur. Conf. Comput. Vis., pages 3-19, 2018. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 299, + 425, + 531, + 466 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 425, + 531, + 466 + ], + "spans": [ + { + "bbox": [ + 299, + 425, + 531, + 466 + ], + "type": "text", + "content": "[56] Xiulong Yang, Sheng-Min Shih, Yinlin Fu, Xiaoting Zhao, and Shihao Ji. Your vit is secretly a hybrid discriminative-generative diffusion model. arXiv preprint arXiv:2208.07791, 2022.3" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 299, + 467, + 531, + 511 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 467, + 531, + 511 + ], + "spans": [ + { + "bbox": [ + 299, + 467, + 531, + 511 + ], + "type": "text", + "content": "[57] Zhu Zhang, Jianxin Ma, Chang Zhou, Rui Men, Zhikang Li, Ming Ding, Jie Tang, Jingren Zhou, and Hongxia Yang. M6-ufc: Unifying multi-modal controls for conditional image synthesis. Adv. Neural Inform. Process. Syst., 2021. 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 299, + 511, + 531, + 544 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 511, + 531, + 544 + ], + "spans": [ + { + "bbox": [ + 299, + 511, + 531, + 544 + ], + "type": "text", + "content": "[58] Jinghao Zhou, Chen Wei, Huiyu Wang, Wei Shen, Cihang Xie, Alan Yuille, and Tao Kong. ibot: Image bert pre-training with online tokenizer. Int. Conf. Learn. Represent., 2022. 3" + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "spans": [ + { + "bbox": [ + 276, + 747, + 300, + 756 + ], + "type": "text", + "content": "23173" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/06acdbbe-e15b-4021-a13d-3cb042fcaf0d_content_list.json b/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/06acdbbe-e15b-4021-a13d-3cb042fcaf0d_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..26b5a218e26854da5a23bb4e894db541c867f88e --- /dev/null +++ b/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/06acdbbe-e15b-4021-a13d-3cb042fcaf0d_content_list.json @@ -0,0 +1,1873 @@ +[ + { + "type": "text", + "text": "Masked Motion Predictors are Strong 3D Action Representation Learners", + "text_level": 1, + "bbox": [ + 111, + 130, + 857, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Yunyao Mao $^{1}$ Jiajun Deng $^{3}$ Wengang Zhou $^{1,2,*}$ Yao Fang $^{5}$ Wanli Ouyang $^{4}$ Houqiang Li $^{1,2,*}$", + "bbox": [ + 91, + 178, + 875, + 200 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{1}$ CAS Key Laboratory of Technology in GIPAS, EEIS Department, University of Science and Technology of China $^{2}$ Institute of Artificial Intelligence, Hefei Comprehensive National Science Center", + "bbox": [ + 107, + 200, + 864, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "3The University of Sydney 4Shanghai AI Laboratory 5Merchants Union Consumer Finance Company Limited", + "bbox": [ + 106, + 234, + 864, + 252 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "myy2016@mail.ustc.edu.cn, jiajun.deng@sydney.edu.au, zhwg@ustc.edu.cn", + "bbox": [ + 176, + 253, + 790, + 268 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "fangyao@mucfc.com, wanli.ouyang@sydney.edu.au, lihq@ustc.edu.cn", + "bbox": [ + 205, + 272, + 764, + 286 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 321, + 313, + 338 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In 3D human action recognition, limited supervised data makes it challenging to fully tap into the modeling potential of powerful networks such as transformers. As a result, researchers have been actively investigating effective self-supervised pre-training strategies. In this work, we show that instead of following the prevalent pretext task to perform masked self-component reconstruction in human joints, explicit contextual motion modeling is key to the success of learning effective feature representation for 3D action recognition. Formally, we propose the Masked Motion Prediction (MAMP) framework. To be specific, the proposed MAMP takes as input the masked spatiotemporal skeleton sequence and predicts the corresponding temporal motion of the masked human joints. Considering the high temporal redundancy of the skeleton sequence, in our MAMP, the motion information also acts as an empirical semantic richness prior that guide the masking process, promoting better attention to semantically rich temporal regions. Extensive experiments on NTU-60, NTU-120, and PKU-MMD datasets show that the proposed MAMP pre-training substantially improves the performance of the adopted vanilla transformer, achieving state-of-the-art results without bells and whistles. The source code of our MAMP is available at https://github.com/maoyunyao/MAMP.", + "bbox": [ + 75, + 353, + 473, + 731 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 760, + 209, + 776 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "How to accurately recognize human actions has been a long-standing challenge in computer vision. Recently, with the advances in techniques of depth sensing and pose estimation [3, 16, 54], skeleton-based 3D human action recognition has become an emerging problem to the community, which is of great significance in a series of applications such", + "bbox": [ + 75, + 786, + 468, + 878 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/ae8114679b8c427baeed90be3a241f1c9d5bf4f842463d1125a19cf23dd20a02.jpg", + "image_caption": [ + "MAE" + ], + "image_footnote": [], + "bbox": [ + 521, + 318, + 691, + 492 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/14e74328e36d018b320e8a5b80517c1ad66d5d2451dca1d9b43ba0773cb900ec.jpg", + "image_caption": [ + "MAMP (Ours)" + ], + "image_footnote": [], + "bbox": [ + 702, + 318, + 872, + 491 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/85481d6e5ef68d8c9395b51b984810604bbd8e15fae81f4b8d1b603df762553a.jpg", + "image_caption": [ + "(a) Comparison of pre-training objectives.", + "(b) Comparison of linear probing accuracy.", + "Figure 1. Illustration of (a) pre-training objective comparison between masked auto encoders (MAE) and our masked motion predictors (MAMP) and (b) performance comparison between the typical MAE method, i.e., SkeletonMAE [53], and our MAMP under the linear evaluation protocol." + ], + "image_footnote": [], + "bbox": [ + 516, + 536, + 870, + 685 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "as human-computer interaction, video surveillance, virtual reality, etc. Despite the computation efficiency and background robustness of skeletons, existing supervised 3D action recognition methods [5, 7, 14, 19, 24, 25, 32, 39, 42, 43, 60] heavily rely on well-annotated training sequences, which are labor-intensive and time-consuming to acquire.", + "bbox": [ + 496, + 809, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding authors: Wengang Zhou and Houqiang Li", + "bbox": [ + 94, + 886, + 403, + 901 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "10181", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Furthermore, limited supervision also leads to the overfitting issue in general models, especially for transformers that are with weak inductive bias and high model capacity. These facts motivate the exploration of self-supervised 3D action representation learning.", + "bbox": [ + 76, + 90, + 468, + 167 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In the literature, the prevalent pretext tasks originally developed for images have been adapted for 3D action representation learning, such as colorization [58], reconstruction [62, 46, 27], contrastive learning [23, 48, 49], etc. Among them, contrastive learning once dominated 3D action representation learning with its concise framework and promising performance. Nevertheless, as a global representation learner, it still suffers from certain limitations, such as the lack of explicit constraints for temporal context modeling and the over-reliance on heuristic action data augmentations [31], impeding its further exploration of 3D actions.", + "bbox": [ + 76, + 169, + 467, + 335 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Recently, as transformers flourish in computer vision, masked autoencoder (MAE) [17] has attracted a surge of research interest for its exceptional performance. Given that a 3D skeleton serves as an abstract representation of human behaviors, there has been growing interest in applying the MAE concept to 3D action representation learning, to capture the underlying spatio-temporal dynamics of skeleton sequences. Early attempts generally followed the practice of images, employing masked self-reconstruction of human joints as the pre-training pretext. Despite considerable effort, we argue that the network is not effectively directed to prioritize contextual motion modeling in such a self-reconstruction objective, which is, however, crucial for comprehending 3D actions as the appearance information is greatly erased in human skeletons. How to better explore the contextual motion clue in self-supervised 3D action representation learning is a valid problem.", + "bbox": [ + 76, + 339, + 467, + 595 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "By consolidating this idea, we introduce Masked Motion Prediction (MAMP), a simple yet effective framework to address the problem of self-supervised 3D action representation learning. Specifically, the proposed MAMP takes as input the masked spatio-temporal skeleton sequence and turns to predict the corresponding temporal motion of the masked human joints. In this way, the network is directly encouraged for contextual motion modeling. Moreover, given the observation that moments with significant motion are often critical for human action understanding, in our MAMP, the temporal motion is used not only as the pretraining objective but also as an empirical semantic richness prior that effectively guiding the skeleton masking process. Compared to the random version, the proposed motion-aware masking strategy takes additional temporal motion intensity as input. It first converts the input intensity into a probability distribution and then utilizes the reparameterization technique for efficient probability-guided masked token sampling. As a result, joints with significant motion are masked with a higher probability, facilitating", + "bbox": [ + 76, + 598, + 467, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "better attention to semantically rich temporal regions.", + "bbox": [ + 498, + 90, + 852, + 106 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "As illustrated in Figure 1, compared to masked self-reconstruction of human joints, masked motion prediction acts as a more effective pretext task for 3D action representation learning. It substantially alleviates the problem that the transformers cannot fully unleash their modeling potential for human actions due to the scarcity of annotated 3D skeletons. The adopted vanilla transformer sets a series of state-of-the-art records in 3D action recognition after MAMP pre-training, without the need for bells and whistles such as multi-stream ensembling. Specifically, compared to training from scratch, our MAMP demonstrates significant absolute performance improvements of $10.0\\%$ and $13.2\\%$ on the challenging cross-subject protocol of NTU RGB+D 60 [38] and NTU RGB+D 120 [28] datasets, resulting in top-1 accuracy of $93.1\\%$ and $90.0\\%$ , respectively. We hope this simple yet effective framework will serve as a strong baseline that facilitates future research on 3D action pretraining and beyond.", + "bbox": [ + 496, + 107, + 890, + 378 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Overall, we make the following three-fold contributions:", + "bbox": [ + 517, + 380, + 888, + 393 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We present masked motion prediction to learn 3D action representation, which substantially alleviates the insufficient contextual motion modeling issue in the conventional masked self-reconstruction paradigm.", + "- We devise the motion-aware masking strategy, which incorporates motion intensity as an empirical semantic richness prior for adaptive joint masking.", + "- We conduct extensive experiments on three prevalent benchmarks to verify the effectiveness of our method. Remarkably, with our proposed MAMP, the vanilla transformer, for the first time, achieves the top-performing record for 3D action recognition." + ], + "bbox": [ + 517, + 396, + 888, + 575 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 593, + 638, + 608 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Supervised 3D Action Recognition", + "text_level": 1, + "bbox": [ + 500, + 619, + 797, + 635 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "How to better model the dynamic skeletons for supervised action recognition is an extensively studied problem. In many early works, RNNs are favored for their excellent sequential modeling capability, such as the hierarchical RNN model proposed in [14] and the 2D Spatio-Temporal LSTM in [30, 29]. In view of the great success of CNNs [21, 18] in image understanding, some methods also try to apply it to 3D action recognition. To cater for the input format, [13] and [22] treat the skeleton sequence as a three-channel (x, y, and z coordinates) pseudo-image, with the number of frames and joints as height and width, respectively. Considering the natural connections between joints, ST-GCN [55] introduces the Graph Neural Networks (GCNs) for skeleton modeling, where the convolution kernels are elaborately designed according to the skeleton topology. The astonishing performance of ST-GCN has led the trend of GCN-based 3D action recognition, with numer", + "bbox": [ + 496, + 643, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "10182", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "ous subsequent improvements emerging in input streams [51, 26, 40], kernel design [5, 61, 39, 32], etc.", + "bbox": [ + 76, + 90, + 468, + 119 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Recent approaches [36, 35, 41] try to introduce the popular vision transformer into 3D action recognition. However, under limited training data, vanilla transformers with weak inductive bias cannot be fully trained. Therefore, many customized designs are required in existing supervised attempts, such as temporal convolution [36], graph convolution [35, 36], space-time separation [41], etc. In our approach, we demonstrate that pre-training with masked motion prediction is key to the success of transformers in 3D action recognition. The proposed MAMP framework endows the vanilla transformer with unrivaled performance.", + "bbox": [ + 75, + 121, + 470, + 287 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Self-supervised 3D Action Recognition", + "text_level": 1, + "bbox": [ + 76, + 297, + 408, + 314 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Self-supervised representation learning aims to capture the domain priors from unlabeled data so as to facilitate the application of the model in downstream tasks. In 3D human action recognition, many pretext tasks have been utilized to explore the action context that resides in the skeleton sequence. Among them, LongT GAN [62] and P&C [46] try to learn 3D action representation by autoencoder-based sequence reconstruction, where the decoder in P&C is further weakened to promote the learning of the feature encoder. In Colorization [58], the skeleton sequences are treated as point clouds and action representation is learned by colorizing each joint based on its spatial and temporal orders.", + "bbox": [ + 75, + 321, + 468, + 501 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Recently, many contrastive learning-based approaches [27, 48, 23, 49, 59, 34] have emerged, showing superior performance compared to earlier works. To learn better 3D action representation, they either try to dig helpful supervision across different skeleton modalities [23, 34], or explore better action data augmentation [49] and positive sample mining strategies [59]. Nevertheless, as a global feature learner originally designed for images, contrastive learning lacks explicit constraints on the exploration of temporal motion context, limiting its further development for 3D actions.", + "bbox": [ + 75, + 503, + 468, + 652 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "SkeletonMAE [53] first introduces the idea of MAE[17] into transformer-based 3D action representation learning, where the original joint coordinates of masked regions are predicted. In our approach, we demonstrate that such a self-reconstruction objective is sub-optimal for learning 3D action representation. Therefore, we introduce the Masked Motion Prediction (MAMP) framework for explicit contextual motion modeling, resulting in significantly better performance compared to raw skeleton reconstruction.", + "bbox": [ + 75, + 654, + 468, + 789 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.3. Masked Visual Prediction", + "text_level": 1, + "bbox": [ + 76, + 801, + 310, + 816 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "With the development of vision transformers [4, 12, 50], the masked prediction derived from the autoencoder [1] has revived again. Similar to the BERT [11] pre-training in NLP, the input tokens are randomly masked and corresponding objectives are predicted, which can be the raw", + "bbox": [ + 76, + 824, + 468, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "pixels [17], HOG features [52], or token ids from offline learned dVAEs [2]. Recently, there have also been attempts [45, 57] to use optical flow or temporal difference of images as the auxiliary reconstruction objectives, but inferior performance is observed when they are applied alone. This is largely attributed to the high redundancy of the raw images, where the key foreground motion is difficult to be pre-extracted accurately. In our approach, we employ the idea of masked visual prediction for 3D action representation learning, with the temporal skeleton motion adopted as the only reconstruction target. Different from images, the explicit temporal correspondence of joints in the human skeleton sequence enables the ready extraction of their accurate motion context. Furthermore, we also incorporate motion intensity as the semantic richness prior to guide the masking process.", + "bbox": [ + 496, + 90, + 890, + 332 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Our Method", + "text_level": 1, + "bbox": [ + 500, + 347, + 629, + 363 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Overview", + "text_level": 1, + "bbox": [ + 500, + 373, + 609, + 387 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Figure 2 illustrates the overall pipeline of our proposed Masked Motion Prediction (MAMP) framework. It takes a skeleton sequence $S \\in \\mathbb{R}^{T_s \\times V \\times C_s}$ as input, which is randomly cropped from the original data and is resized to a fixed temporal length $T_s$ . $V$ and $C_s$ are the number of joints and coordinate channels, respectively. The motion sequence $M \\in \\mathbb{R}^{T_s \\times V \\times C_s}$ of the input is also extracted, which is defined as the differential on temporal dimension (manually padded for the first frame).", + "bbox": [ + 496, + 396, + 890, + 532 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "As in most vision transformers, the input joints are linearly mapped into joint embedding $E \\in \\mathbb{R}^{T_e \\times V \\times C_e}$ . After that, the motion-aware masking strategy is applied to mask most of the embedding features under the guidance of temporal motion intensity. The remaining features are processed by the encoder-decoder architecture, where the transformer encoder learns representation from unmasked joint embedding and the transformer decoder performs contextual modeling based on the learnable mask tokens and latent representation from the transformer encoder. Different from MAE [17] that reconstructs the original signal for representation learning, in MAMP, a motion prediction head is adopted, which takes decoded features as input and predicts the temporal motion of the input skeleton sequence.", + "bbox": [ + 496, + 532, + 890, + 743 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "After the aforementioned pre-training, only the joint embedding layer and the transformer encoder are reserved for downstream applications.", + "bbox": [ + 496, + 744, + 890, + 790 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Joint Embedding", + "text_level": 1, + "bbox": [ + 500, + 801, + 668, + 816 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In most transformer-based attempts [35, 41, 36], each spatio-temporal skeleton joint is embedded separately, resulting in a large number of input tokens. Considering the temporal redundancy, in our approach, the input skeleton sequence $S \\in \\mathbb{R}^{T_s \\times V \\times C_s}$ is divided into temporally non", + "bbox": [ + 496, + 824, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "10183", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/143a150f455a8b964d76bd570a1c774e28c1e45e014ed5486ec7457b324ee9f3.jpg", + "image_caption": [ + "Figure 2. The overall pipeline of the proposed MAMP framework. Different from the self-reconstruction scheme adopted in previous works [62, 53], our MAMP learns 3D action representation by predicting the corresponding motion sequence for masked joint input. Moreover, motion information also acts as an empirical semantic richness prior that effectively guides the masking process, enabling more attention to be applied to regions with significant temporal motion intensity." + ], + "image_footnote": [], + "bbox": [ + 81, + 88, + 893, + 270 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "overlapping segments $S' \\in \\mathbb{R}^{T_e \\times V \\times l \\times C_s}$ , where $l$ is the length of each segment and $T_e = T_s / l$ . In each segment, joints with the same spatial position are embedded together:", + "bbox": [ + 75, + 356, + 468, + 402 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nE = \\operatorname {J o i n t E m b e d} \\left(S ^ {\\prime}\\right) \\in \\mathbb {R} ^ {T _ {e} \\times V \\times C _ {e}}, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 140, + 415, + 468, + 434 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $C_e$ is the dimension of the embedding features. Compared to the original skeleton sequence, the temporal resolution of the embedding $E$ is reduced by a factor of $l$ , resulting in higher computational efficiency.", + "bbox": [ + 76, + 439, + 468, + 501 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Motion Extraction", + "text_level": 1, + "bbox": [ + 76, + 508, + 256, + 523 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Different from RGB frames with heavy spatial redundancy, the human skeleton sequence is highly semantic, with explicit correspondence between neighboring frames. Therefore, we can easily obtain its motion $M \\in \\mathbb{R}^{T_s \\times V \\times C_s}$ by applying temporal difference on joint coordinates:", + "bbox": [ + 76, + 532, + 468, + 609 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nM _ {i,:,:} = S _ {i,:,:} - S _ {i - m,:,:}, i \\in m, m + 1, \\dots , T _ {s} - 1, \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 86, + 619, + 468, + 638 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where stride $m$ controls the step size of the motion. For convenience, the motion sequence is padded to be consistent with the length of the original input:", + "bbox": [ + 76, + 648, + 468, + 694 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nM _ {0: m - 1,:,:} = \\left\\{ \\begin{array}{l l} 0, & \\text {c o n s t a n t} \\\\ M _ {m: 2 m - 1,:,:}, & \\text {r e p l i c a t e} \\end{array} , \\right. \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 122, + 704, + 468, + 736 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where constant and replicate denote constant padding (with zeros) and replicate padding for the first $m$ frames of the motion sequence, respectively.", + "bbox": [ + 76, + 747, + 468, + 792 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.4. Motion-Aware Masking", + "text_level": 1, + "bbox": [ + 76, + 801, + 295, + 816 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In the proposed approach, the motion information is used not only as the reconstruction target during pre-training but also as the empirical semantic richness prior that guiding the masking of embedding features. Considering that the skeleton sequence is segment-wise embedded with length $l$ ,", + "bbox": [ + 76, + 825, + 468, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "we extract the motion sequence $M^{\\mathrm{mask}} \\in \\mathbb{R}^{T_i \\times V \\times C_i}$ with stride $m = l$ and replicate padding according to Eq. (2) and Eq. (3), which is further reshaped into $M' \\in \\mathbb{R}^{T_e \\times V \\times l \\times C_i}$ as is done for $S'$ . Then, the motion intensity $I$ , which indicates the motion significance of each spatio-temporal segment, is computed as follows:", + "bbox": [ + 496, + 356, + 890, + 446 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nI = \\sum_ {i = 0} ^ {l} \\sum_ {j = 0} ^ {C _ {i}} \\left| M _ {:,:,: i, j} ^ {\\prime} \\right| \\in \\mathbb {R} ^ {T _ {e} \\times V}. \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 586, + 455, + 890, + 500 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Since human actions are composed of a series of temporal movements, we argue that the intensity of motion largely reflects the semantic richness. Therefore in MAMP, the motion intensity is further converted into probability distribution with a temperature hyper-parameter $\\tau$ :", + "bbox": [ + 496, + 507, + 890, + 583 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\pi = \\operatorname {S o f t m a x} (I / \\tau), \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 620, + 592, + 890, + 609 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "which indicates the probability that each embedding feature is masked. In MAMP, the idea of gumble max is adapted for efficient probability-guided mask index sampling:", + "bbox": [ + 496, + 617, + 890, + 662 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} g = - \\log (- \\log \\epsilon), \\epsilon \\in U [ 0, 1 ] ^ {T _ {\\epsilon} \\times V}, \\\\ i d x ^ {\\text {m a s k}} = \\text {I n d e x - o f - T o p - K} (\\log \\pi + g), \\tag {6} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 550, + 670, + 890, + 709 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $U[0,1]$ denotes uniform distribution between 0 and 1. The obtained $idx^{\\mathrm{mask}}$ indicates which joints are masked and is used for unmasked token selection in Section 3.5. Based on the above operations, the network is encouraged to focus more on semantically rich regions, so as to learn more discriminative 3D action representation.", + "bbox": [ + 496, + 717, + 890, + 808 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.5. Masked Motion Prediction", + "text_level": 1, + "bbox": [ + 500, + 816, + 741, + 830 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We follow the encoder-decoder design in MAE [17], where the transformer encoder focuses on representation learning, while the decoder is responsible for the implementation of the pre-training pretext.", + "bbox": [ + 496, + 839, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "10184", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Encoder: In the encoder, separate spatio-temporal positional embedding $P_{e}^{s} \\in \\mathbb{R}^{1 \\times V \\times C_{e}}$ and $P_{e}^{t} \\in \\mathbb{R}^{T_{e} \\times 1 \\times C_{e}}$ are first element-wise added (with broadcasting) to the input joint embedding $E$ :", + "bbox": [ + 75, + 90, + 468, + 151 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nE _ {p} = E + P _ {e} ^ {s} + P _ {e} ^ {t}. \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 200, + 157, + 468, + 174 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Then, the unmasked tokens in $E_{p}$ are selected according to the $idx^{\\mathrm{mask}}$ extracted in Eq. (6) and are flattened to $E_{p}^{u} \\in \\mathbb{R}^{N_{u} \\times C_{e}}$ , where $N_{u} = T_{e} \\times V \\times (1 - \\mathrm{mask~ratio})$ is the number of unmasked tokens. After that, the latent representation is extracted by $L_{e}$ vanilla transformer blocks:", + "bbox": [ + 76, + 180, + 468, + 255 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nH _ {0} = E _ {p} ^ {u},\n$$\n", + "text_format": "latex", + "bbox": [ + 102, + 261, + 176, + 279 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nH _ {l} ^ {\\prime} = \\operatorname {M S A} \\left(\\ln \\left(H _ {l - 1}\\right)\\right) + H _ {l - 1}, \\quad l \\in 1, \\dots , L _ {e} \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 106, + 281, + 468, + 305 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nH _ {l} = \\operatorname {M L P} \\left(\\operatorname {L N} \\left(H _ {l} ^ {\\prime}\\right)\\right) + H _ {l} ^ {\\prime}, \\quad l \\in 1, \\dots , L _ {e}\n$$\n", + "text_format": "latex", + "bbox": [ + 106, + 300, + 452, + 316 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nH _ {e} ^ {u} = \\mathrm {L N} \\left(H _ {L _ {e}}\\right),\n$$\n", + "text_format": "latex", + "bbox": [ + 102, + 320, + 217, + 335 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where MSA, MLP, and LN denote multi-head self-attention, multilayer perceptron, and layer norm, respectively.", + "bbox": [ + 75, + 340, + 467, + 371 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Decoder: In the decoder, the learnable mask tokens are inserted into $H_{e}^{u}$ according to the mask indices $idx^{\\mathrm{mask}}$ . The result is reshaped back to $H_{e} \\in \\mathbb{R}^{T_{e} \\times V \\times C_{e}}$ , which is processed by $L_{d}$ decoder layers for masked modeling:", + "bbox": [ + 75, + 371, + 468, + 431 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nZ _ {0} = H _ {e} + P _ {d} ^ {s} + P _ {d} ^ {t},\n$$\n", + "text_format": "latex", + "bbox": [ + 104, + 436, + 254, + 454 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nZ _ {l} ^ {\\prime} = \\operatorname {M S A} \\left(\\ln \\left(Z _ {l - 1}\\right)\\right) + Z _ {l - 1}, \\quad l \\in 1, \\dots , L _ {d} \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 107, + 455, + 468, + 481 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nZ _ {l} = \\operatorname {M L P} \\left(\\ln \\left(Z _ {l} ^ {\\prime}\\right)\\right) + Z _ {l} ^ {\\prime}, \\quad l \\in 1, \\dots , L _ {d}\n$$\n", + "text_format": "latex", + "bbox": [ + 107, + 474, + 468, + 492 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nZ _ {d} = \\operatorname {L N} \\left(Z _ {L _ {d}}\\right),\n$$\n", + "text_format": "latex", + "bbox": [ + 107, + 494, + 214, + 511 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $P_{d}^{s}$ and $P_{d}^{t}$ are the spatial and temporal positional embedding of the transformer decoder, respectively.", + "bbox": [ + 75, + 517, + 468, + 547 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Motion Prediction: In our method, the reconstruction target is not the original skeletons, but the motion sequence $M^{\\mathrm{target}}$ pre-extracted according to Eq. (2) and Eq. (3), which is normalized by its segment-wise mean and standard deviation as in [17]. Therefore, given the decoded feature $Z_{d} \\in \\mathbb{R}^{T_{e} \\times V \\times C_{d}}$ , we additionally adopt a prediction head to predict the temporal motion of masked human joints:", + "bbox": [ + 75, + 547, + 468, + 654 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nM ^ {\\text {p r e d}} = \\text {M o t i o n P r e d H e a d} \\left(Z _ {d}\\right), \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 153, + 659, + 468, + 676 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where we empirically find that a simple fully connected layer just works well. For masked human joints, we compute the mean squared error (MSE) between the predicted result $M^{\\mathrm{pred}}$ and the reconstruction target $M^{\\mathrm{target}}$ :", + "bbox": [ + 75, + 681, + 468, + 743 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} = \\frac {1}{| i d x ^ {\\text {m a s k}} |} \\sum_ {(i, j) \\in i d x ^ {\\text {m a s k}}} \\| \\left(M _ {i, j,:} ^ {\\text {p r e d}} - M _ {i, j,:} ^ {\\text {t a r g e t}}\\right) \\| _ {2} ^ {2}. \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 99, + 748, + 468, + 785 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 792, + 207, + 808 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Datasets and Evaluation Protocols", + "text_level": 1, + "bbox": [ + 76, + 816, + 375, + 830 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "NTU-RGB+D 60 [38]: NTU-RGB+D 60 (NTU-60) is a large-scale dataset for human action recognition. It contains 60 action categories performed by 40 different subjects, with a total of 56,880 3D skeleton sequences. In this", + "bbox": [ + 75, + 839, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "paper, we adopt the evaluation protocols recommended by the authors, namely cross-subject (X-sub) and cross-view (X-view). The former, X-sub uses the action sequences performed by half of the 40 subjects as training samples and the rest as test samples. For X-view, the training samples are action sequences captured by cameras 2 and 3, and the test samples are those captured by camera 1.", + "bbox": [ + 496, + 90, + 890, + 196 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "NTU-RGB+D 120 [28]: NTU-RGB+D 120 (NTU120) is an extended version of NTU-60, in which the number of action categories is increased from 60 to 120, the number of total skeleton sequences and subjects are also increased to 114,480 and 106, respectively. Furthermore, the authors also introduce a more challenging evaluation protocol named cross-setup (X-set) to substitute for the original X-view in NTU-60. Specifically, X-set divides sequences into 32 different setups based on the camera distance and background. Samples from half of these setups are used as the training set and the remainder constitute the test set.", + "bbox": [ + 496, + 196, + 890, + 362 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "PKU-MMD [9]: Following [48], to perform 3D action classification on PKU-MMD, we crop out action instances based on temporal annotations and divide them into training and test sets according to the cross-subject protocol. PKU-MMD contains two phases: PKU-MMD I (PKU-I) and PKU-MMD II (PKU-II). In PKU-I, the number of samples in training and test sets are 18,841 and 2,704, respectively. Due to the more noise introduced by the larger view variation, PKU-II is more challenging, with 5,332 samples for training and 1,613 for testing.", + "bbox": [ + 496, + 364, + 890, + 515 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Experimental Setup", + "text_level": 1, + "bbox": [ + 500, + 527, + 689, + 542 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Network Architecture: In our MAMP framework, we adopt a vanilla vision transformer [12] as the backbone network, which consists of $L_{e} = 8$ identical building blocks. In each block, the embedding dimension is 256, the head number of the multi-head self-attention module is 8, and the hidden dimension of the feed-forward network is 1024. We employ learnable spatio-temporal separated positional embedding to the embedded inputs. The settings of the transformer decoder used during pre-training are consistent with those of the backbone encoder except that the number of layers $L_{d}$ is reduced to 5.", + "bbox": [ + 496, + 551, + 890, + 717 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Data Processing Details: Given an original skeleton sequence, a contiguous segment is first randomly cropped from it with a certain proportion $p$ ( $p$ is sampled from [0.5,1] during training and fixed to 0.9 during the test). After that, the cropped segment is resized to a fixed length $T_{s}$ by bilinear interpolation. $T_{s}$ is set to 120 by default.", + "bbox": [ + 496, + 718, + 890, + 808 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Pre-training Details: During pre-training, the masking ratio of the input token is set to $90\\%$ . The target motion sequence $M^{\\mathrm{target}}$ has stride $m = 1$ and is padded with zeros. We adopt the AdamW [33] optimizer with a weight decay of 0.05 and betas of (0.9, 0.95). We pre-train the network for 400 epochs with a batch size of 128. The learning rate", + "bbox": [ + 496, + 810, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "10185", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/24b554f11c4062f338fa57517aff19c7396076438b8bcfbe196ced8e2b76f596.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodInput streamNTU-60NTU-120PKU-MMD
X-subX-viewX-subX-setPhase IPhase II
3s-SkeletonCLR [23]Joint+Motion+Bone75.079.860.762.685.3-
3s-CrosSCLR [23]Joint+Motion+Bone77.883.467.966.784.921.2
3s-AimCLR [49]Joint+Motion+Bone78.983.868.268.887.439.5
LongT GAN [62]Joint only39.148.1--67.726.0
P&C [46]Joint only50.776.342.741.759.925.5
MS2L [27]Joint only52.6---64.927.6
AS-CAL [37]Joint only58.564.848.649.2--
ISC [48]Joint only76.385.267.167.980.936.0
GL-Transformer [20]Joint only76.383.866.068.7--
CPM [59]Joint only78.784.968.769.688.848.3
CMD [34]Joint only79.486.970.371.5-43.0
SkeletonMAE* [53]Joint only74.877.772.573.582.836.1
MAMP (Ours)Joint only84.989.178.679.192.253.8
", + "bbox": [ + 80, + 88, + 885, + 321 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/700861410cbd8fec26af37c07e759b6ea81abdaff2ae8fefc506acc8f9044b2b.jpg", + "table_caption": [ + "Table 1. Performance comparison on the NTU-60, NTU-120, and PKU-MMD datasets under the linear evaluation protocol. * indicates the re-implemented version under our framework, where improved performance is achieved." + ], + "table_footnote": [], + "table_body": "
MethodBackboneNTU-60
X-subX-view
CPM [59]ST-GCN84.891.1
CrossCLR [23]3s-ST-GCN86.292.5
AimCLR [49]3s-ST-GCN86.992.8
CrossCLR [23]STTFormer84.690.5
AimCLR [49]STTFormer83.990.4
SkeletonMAE [53]STTFormer86.692.9
Colorization [58]3s-DGCNN88.094.9
MCC [47]2s-AGCN89.796.3
ViA [56]2s-UINK89.696.4
Hi-TRS [6]3s-Transformer90.095.7
W/o pre-trainingTransformer83.192.6
SkeletonMAE* [53]Transformer88.594.7
MAMP (Ours)Transformer93.197.5
", + "bbox": [ + 80, + 367, + 460, + 598 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "is linearly increased to 1e-3 from 0 in the first 20 warm-up epochs and then decreased to 5e-4 by the cosine decay schedule. The experiments are conducted using the PyTorch framework on four NVIDIA RTX 3090 GPUs.", + "bbox": [ + 75, + 656, + 468, + 717 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Comparison with State-of-the-art Methods", + "text_level": 1, + "bbox": [ + 76, + 726, + 441, + 742 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Linear Evaluation Results: In linear evaluation protocol, the pre-trained backbone is fixed and a post-attached linear classifier is trained with supervision for 100 epochs with a batch size of 256 and a learning rate of 0.1. The learning rate is decreased to 0 by the cosine decay schedule. As shown in Table 1, the performance on three datasets are reported, they are NTU-60, NTU-120, and PKU-MMD, respectively. We include latest high-performance approaches for comparison, e.g., GL-Transformer [20], CPM [59], CMD [34], 3s-CrosSLR [23], and 3s-AimCLR [49]. As", + "bbox": [ + 75, + 750, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/8dee45f3f9e304360d6d06cdde8642984d6265f219e58ae3446d2c6bc1ef8b0b.jpg", + "table_caption": [ + "Table 2. Performance comparison on the NTU-60 dataset under the fine-tuned evaluation protocol." + ], + "table_footnote": [], + "table_body": "
MethodBackboneNTU-120
X-subX-set
CPM [59]ST-GCN78.478.9
CrosCLR [23]3s-ST-GCN80.580.4
AimCLR [49]3s-ST-GCN80.180.9
CrosCLR [23]STTFormer75.077.9
AimCLR [49]STTFormer74.677.2
SkeletonMAE [53]STTFormer76.879.1
MCC [47]2s-AGCN81.383.3
ViA [56]2s-UINK85.086.5
Hi-TRS [6]3s-Transformer85.387.4
W/o pre-trainingTransformer76.879.7
SkeletonMAE* [53]Transformer87.088.9
MAMP (Ours)Transformer90.091.3
", + "bbox": [ + 504, + 367, + 883, + 583 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/26a3cb984d2703734b9f8c0e1a6165f2955be8d813a684de8d0480976b16e745.jpg", + "table_caption": [ + "Table 3. Performance comparison on the NTU-120 dataset under the fine-tuned evaluation protocol." + ], + "table_footnote": [], + "table_body": "
MethodNTU-60NTU-120
X-subX-viewX-subX-set
PoseC3D [15]93.796.686.089.6
CTR-CGN [5]92.496.888.990.6
InfoGCN [8]93.097.189.891.2
MAMP (Ours)93.197.590.091.3
", + "bbox": [ + 506, + 635, + 880, + 731 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 4. Performance comparison with fully-supervised methods on the NTU-60 and NTU-120 datasets. Note that our MAMP does not perform multi-stream ensembling during evaluation.", + "bbox": [ + 498, + 734, + 890, + 777 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "we can see, with the joint stream as the only input, our proposed MAMP outperforms these methods on all the datasets. Specifically, MAMP outperforms previous state-of-the-art method CMD by $5.5\\%$ and $8.3\\%$ on the challenging NTU-60 x-sub and NTU-120 x-sub, respectively. For a fair comparison, we also re-implement the Skeleton", + "bbox": [ + 496, + 810, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "10186", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "MAE [53] under the same settings as our approach (denote as SkeletonMAE*), where improved performance is achieved. We can find that our MAMP significantly outperforms SkeletonMAE* on all six subsets of the three datasets, demonstrating the superiority of masked motion prediction compared to the self-reconstruction of joints.", + "bbox": [ + 75, + 90, + 470, + 181 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Fine-tuned Evaluation Results: In fine-tuned evaluation protocol, an MLP head is attached to the pre-trained backbone and the whole network is fully fine-tuned for 100 epochs with a batch size of 48. The learning rate is linearly increased to 3e-4 from 0 in the first 5 warm-up epochs and then decreased to 1e-5 by the cosine decay schedule. We also adopt layer-wise lr decay [10] following [2]. As shown in Table 2 and Table 3, we evaluate the fine-tuned performance on NTU-60 and NTU-120, respectively. The vanilla transformer does not show satisfactory performance when trained directly from scratch, which is under expectation as weakly biased transformers require a large amount of training data to effectively prevent overfitting. After being pre-trained with the proposed MAMP framework, the network exhibits significant performance improvements ranging from $5\\%$ to $13\\%$ on the four subsets of the NTU-60 and NTU-120 datasets. The final results exceed all previous methods, even those with multi-stream ensembling such as Colorization [58], MCC [47], and ViA [56]. Moreover, our MAMP also outperforms the re-implemented Skeleton-MAE* by a considerable margin.", + "bbox": [ + 75, + 183, + 473, + 501 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We also compare our MAMP with the top-performing supervised methods like PoseC3D [15], CTR-GCN [5], and InfoGCN [8] in Table 4. Results show that without ensembling, MAMP outperforms most top-performing methods, especially on the larger NTU-120 dataset.", + "bbox": [ + 75, + 503, + 468, + 578 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Semi-supervised Evaluation Results: Following previous works [23, 34, 48], in semi-supervised evaluation protocol, the post-attached classification layer and the pre-trained encoder are fine-tuned together with only a small fraction of the training set. Apart from that, we keep other training settings consistent with the fine-tuned evaluation protocol. As in [23, 49, 59], we report the performance on the NTU-60 dataset when using $1\\%$ and $10\\%$ of the training set. Note that considering the randomness during training data selection, we report the average of five runs as the final results. As shown in Table 5, our proposed MAMP significantly outperforms previous works like 3s-AimCLR [49], CPM [59], CMD [34], and SkeletonMAE* [53]. When using only $1\\%$ of the training data, MAMP outperforms SkeletonMAE* by $11.6\\%$ and $14.0\\%$ in X-sub and X-view respectively. Compared to training from scratch, MAMP pretraining brings performance improvements of more than $15.5\\%$ on all subsets of NTU-60.", + "bbox": [ + 75, + 580, + 470, + 851 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Transfer Learning Evaluation Results: In transfer learning evaluation protocol, the network is pre-trained on a source dataset and then finetuned on a different target", + "bbox": [ + 75, + 854, + 472, + 902 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/d082f9fe7a401e07ec8ede68f1f8cd93da406233e4dd61a34229d18d401e7c63.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodNTU-60
X-subX-view
(1%)(10%)(1%)(10%)
LongT GAN [62]35.262.0--
MS2L [27]33.165.1--
ASSL [44]-64.3-69.8
ISC [48]35.765.938.172.5
3s-CrosSCLR [23]51.174.450.077.8
3s-Colorization [58]48.371.752.578.9
CMD [34]50.675.453.080.2
3s-Hi-TRS [6]49.377.751.581.1
3s-AimCLR [49]54.878.254.381.6
3s-CMD [34]55.679.055.582.4
CPM [59]56.773.057.577.1
W/o pre-training38.870.840.476.0
SkeletonMAE* [53]54.480.654.683.5
MAMP (Ours)66.088.068.791.5
", + "bbox": [ + 504, + 88, + 885, + 351 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/496793e953c4b0970ac242357e86949ff63e8a945f5c8d86c4bc54000802d1bf.jpg", + "table_caption": [ + "Table 5. Performance comparison on the NTU-60 dataset under the semi-supervised evaluation protocol. We report the average of five runs as the final performance." + ], + "table_footnote": [], + "table_body": "
MethodTo PKU-II
NTU-60NTU-120PKU-I
LongT GAN [62]44.8-43.6
MS²L [27]45.8-44.1
ISC [48]51.152.345.1
CMD [34]56.057.0-
SkeletonMAE* [53]58.461.062.5
MAMP (Ours)70.673.270.1
", + "bbox": [ + 503, + 410, + 885, + 537 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 6. Performance comparison on the PKU-II dataset under the transfer learning evaluation protocol. The source datasets are the NTU-60, NTU-120, and PKU-I datasets.", + "bbox": [ + 498, + 541, + 893, + 583 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "dataset. In this way, the generalizability of the learned representation is verified. In this paper, the target dataset is PKU-MMD II and the source datasets are NTU-60, NTU-120, and PKU-MMD I, respectively. Results in Table 6 show that, compared to previous methods, the representation learned by our proposed MAMP framework exhibits the best transferability, outperforming the reproduced SkeletonMAE* [53] by $12.2\\%$ , $12.2\\%$ , and $7.6\\%$ on the three source datasets, respectively.", + "bbox": [ + 496, + 609, + 893, + 748 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4. Ablation Study", + "text_level": 1, + "bbox": [ + 498, + 755, + 653, + 772 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Superiority of Masked Motion Prediction: As shown in Table 7, to verify the superiority of masked motion prediction, we designed four different ablative experiments. Given the joint and motion streams of the original data, all possible choices of the model input and reconstruction target are traversed. We can find that our joint-to-motion prediction significantly outperforms other strategies. Under the linear evaluation protocol, our MAMP exceeds joint-to-joint pre", + "bbox": [ + 496, + 779, + 893, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "10187", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/f784a4107d56e905adb406dbb19a072785564cca05a75b55cc3c85450cdc67ad.jpg", + "image_caption": [ + "Figure 3. Pre-training loss plot. Compared to masked self-reconstruction of joints in SkeletonMAE, masked motion prediction acts as a harder pre-training objective." + ], + "image_footnote": [], + "bbox": [ + 89, + 88, + 346, + 217 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/a42f403a663c5865d71429e1234acfd34e57bb9b298836e962c8a6469be7a944.jpg", + "image_caption": [ + "Figure 4. Ablation study on the masking ratio. The performance is evaluated on the NTU-60 X-sub dataset under the linear evaluation protocol." + ], + "image_footnote": [], + "bbox": [ + 356, + 88, + 614, + 218 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/d512013717936363dde230c01cda2c4bd4602f971711e4c28c904df9f9111b46.jpg", + "image_caption": [ + "Figure 5. Pre-training schedule of SkeletonMAE and our MAMP. The performance is evaluated on the NTU-60 X-sub dataset under the linear evaluation protocol." + ], + "image_footnote": [], + "bbox": [ + 625, + 87, + 883, + 217 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/48b00ef1203e09c82d237d456ab57af8b2e8082390d21efdd52a92c34dc49956.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
InputTargetNTU-60NTU-120
JointJoint74.872.5
Motion84.978.6
MotionJoint76.571.0
Motion75.970.5
", + "bbox": [ + 96, + 300, + 447, + 383 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/1e273c1fd1a06494268cc3f70707bd8e0d4b7d100f5f25a6410a5fa545d510fb.jpg", + "table_caption": [ + "Table 7. Ablation study on the superiority of masked motion prediction. The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol." + ], + "table_footnote": [], + "table_body": "
StrategyNTU-60NTU-120
Random masking83.777.3
Motion-aware masking84.978.6
", + "bbox": [ + 94, + 441, + 447, + 494 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "dition (adopted by [53]) by $10.1\\%$ and $6.1\\%$ on NTU-60 and NTU-120, respectively. This suggests that predicting dynamic motion from static skeletons during pre-training facilitates better contextual modeling of 3D human actions.", + "bbox": [ + 76, + 566, + 468, + 626 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We also visualize the pre-training loss in Figure 3. Unlike the fast convergence of SkeletonMAE, masked motion prediction serves as a much harder pre-training objective.", + "bbox": [ + 76, + 627, + 468, + 672 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Mask Sampling Strategy: In our approach, we employ the vanilla transformer as the backbone network, where embedding features at any spatio-temporal location can be freely masked as in MAE [17]. To verify the effectiveness of the proposed motion-aware masking strategy, we compare its performance with that of random masking in Table 8. As we can see, our motion-aware masking strategy brings absolute performance improvements of $1.2\\%$ and $1.3\\%$ on NTU-60 and NTU-120, respectively. This suggests that the motion information, as an empirical semantic richness prior, can effectively guide the skeleton masking process.", + "bbox": [ + 75, + 672, + 468, + 839 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Segment Length: We evaluated the performance of the learned representation under different segment lengths $l$ used in the joint embedding process. For a fair comparison, we resize the original input sequence to ensure that the", + "bbox": [ + 75, + 839, + 468, + 901 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/1d8e33d37b1dbe5b9a055f56a3d570d3355789846b680c2a860f882bc67a2aa0.jpg", + "table_caption": [ + "Table 8. Ablation study on the mask sampling strategy. The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol." + ], + "table_footnote": [], + "table_body": "
Te=Ts/lTslNTU-60NTU-120
3060284.677.8
120484.978.6
180683.378.6
240884.577.9
", + "bbox": [ + 532, + 300, + 857, + 382 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/44826abffb091b5631362cd5fda6782ad1c3fd5e9c1a195fd1c8d40e3d4f122c.jpg", + "table_caption": [ + "Table 9. Ablation study on the segment length $l$ used in the joint embedding process. For a fair comparison, the input length $T_{s}$ is adjusted to ensure that the embedded features have a fixed length $T_{e}$ . The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol." + ], + "table_footnote": [], + "table_body": "
LdNTU-60NTU-120
283.377.2
384.977.6
484.677.5
584.978.6
", + "bbox": [ + 511, + 468, + 686, + 551 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/eb83eb619f7659901b3462c1c769cc08f403bbc5fd20ddfa84c095838c5883cd.jpg", + "table_caption": [ + "(a) Decoder depth." + ], + "table_footnote": [], + "table_body": "
CdNTU-60NTU-120
6482.374.2
12883.577.3
25684.978.6
51284.577.1
", + "bbox": [ + 702, + 468, + 880, + 551 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "(b) Decoder width.", + "bbox": [ + 733, + 556, + 846, + 569 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 10. Ablation study on the decoder design. The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol.", + "bbox": [ + 498, + 574, + 890, + 617 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "embedded features have a fixed length $T_{e} = T_{s} / l = 30$ . As shown in Table 9, a segment length of 4 brings the best performance on both NTU-60 and NTU-120 datasets.", + "bbox": [ + 496, + 643, + 890, + 688 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Decoder Design: We experimented with different numbers of layers and widths (feature dimensions) for the transformer decoder. As shown in Table 10 (a), our MAMP exhibits the best performance on the NTU-60 and NTU-120 datasets when the number of decoder layers is 3 and 5, respectively. The experimental results of the decoder width are in Table 10 (b), where a width of 256 brings the best performance. Overall, a decoder with 5 layers and a width of 256 is adopted in our MAMP framework by default.", + "bbox": [ + 496, + 688, + 890, + 824 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Masking Ratio: As shown in Figure 4, we experimented with different masking ratios. Results on NTU-60 X-sub show that either too large or too small masking ratios have a negative impact on performance. We empirically found that a masking ratio of $90\\%$ exhibits the best results.", + "bbox": [ + 496, + 824, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "10188", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Pre-training Schedule: We studied the influence of the pre-training schedule length. As shown in Figure 5, both SkeletonMAE and our MAMP exhibit higher performance with longer pre-training schedules. It is worth mentioning that our MAMP significantly outperforms SkeletonMAE for all pre-training schedules with lengths ranging from 80 to 400 epochs, demonstrating the stability and superiority of the proposed masked motion prediction strategy.", + "bbox": [ + 75, + 90, + 472, + 213 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 224, + 194, + 239 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this work, we present MAMP, a simple yet effective framework for 3D action representation learning. We show that compared to conventional masked self-reconstruction of human joints, masked joint-to-motion prediction is demonstrated to be more effective for contextual motion modeling of 3D human actions. Given the high temporal redundancy of the skeleton sequence, we further devise the motion-aware masking strategy, which incorporates motion intensity as the empirical semantic richness prior for adaptive skeleton masking, facilitating better attention to semantically rich temporal regions. We conduct extensive experiments on three prevalent benchmarks under four evaluation protocols. Results show that the proposed MAMP brings remarkable performance improvements and sets a series of new state-of-the-art records, unleashing the tremendous potential of vanilla transformers for 3D action modeling.", + "bbox": [ + 75, + 250, + 472, + 492 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement: This work was supported by NSFC under Contract U20A20183 & 61836011. It was also supported by the GPU cluster built by MCC Lab of Information Science and Technology Institution, USTC, and the Supercomputing Center of the USTC.", + "bbox": [ + 75, + 506, + 470, + 583 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 594, + 173, + 609 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Dana H Ballard. Modular learning in neural networks. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), volume 647, pages 279-284, 1987. 3", + "[2] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. BEiT: BERT pre-training of image transformers. In Proceedings of the International Conference on Learning Representations (ICLR), 2022. 3, 7", + "[3] Z. Cao, G. Hidalgo, T. Simon, S. Wei, and Y. Sheikh. OpenPose: Realtime multi-person 2D pose estimation using part affinity fields. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 43(01):172-186, 2021. 1", + "[4] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Proceedings of the European Conference on Computer Vision (ECCV), pages 213-229, 2020. 3", + "[5] Yuxin Chen, Ziqi Zhang, Chunfeng Yuan, Bing Li, Ying Deng, and Weiming Hu. Channel-wise topology refinement graph convolution for skeleton-based action recognition. In Proceedings of the IEEE/CVF International Conference on" + ], + "bbox": [ + 86, + 619, + 470, + 901 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Computer Vision (ICCV), pages 13359-13368, 2021. 1, 3, 6, 7", + "[6] Yuxiao Chen, Long Zhao, Jianbo Yuan, Yu Tian, Zhaoyang Xia, Shijie Geng, Ligong Han, and Dimitris N Metaxas. Hierarchically self-supervised transformer for human skeleton representation learning. In Proceedings of the European Conference on Computer Vision (ECCV), pages 185-202, 2022. 6, 7", + "[7] Ke Cheng, Yifan Zhang, Xiangyu He, Weihan Chen, Jian Cheng, and Hanqing Lu. Skeleton-based action recognition with shift graph convolutional network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 183-192, 2020. 1", + "[8] Hyung-gun Chi et al. InfoGCN: Representation learning for human skeleton-based action recognition. In CVPR, 2022. 6, 7", + "[9] Liu Chunhui, Hu Yueyu, Li Yanghao, Song Sijie, and Liu Jiaying. PKU-MMD: A large scale benchmark for continuous multi-modal human action understanding. arXiv preprint arXiv:1703.07475, 2017. 5", + "[10] Kevin Clark, Minh-Thang Luong, Quoc V. Le, and Christopher D. Manning. ELECTRA: Pre-training text encoders as discriminators rather than generators. In ICLR, 2020. 7", + "[11] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. BERT: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of the Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (NAACL-HLT), pages 4171–4186, 2019. 3", + "[12] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In Proceedings of the International Conference on Learning Representations (ICLR), 2021. 3, 5", + "[13] Yong Du, Yun Fu, and Liang Wang. Skeleton based action recognition with convolutional neural network. In Proceedings of the Asian Conference on Pattern Recognition (ACPR), pages 579-583, 2015. 2", + "[14] Yong Du, Wei Wang, and Liang Wang. Hierarchical recurrent neural network for skeleton based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1110-1118, 2015. 1, 2", + "[15] Haodong Duan et al. Revisiting skeleton-based action recognition. In CVPR, 2022. 6, 7", + "[16] Hao-Shu Fang, Shuqin Xie, Yu-Wing Tai, and Cewu Lu. RMPE: Regional multi-person pose estimation. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 2334-2343, 2017. 1", + "[17] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 16000-16009, 2022. 2, 3, 4, 5, 8" + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "10189", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[18] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR), pages 770-778, 2016. 2", + "[19] Qiuhong Ke, Mohammed Bennamoun, Senjian An, Ferdous Sohel, and Farid Boussaid. A new representation of skeleton sequences for 3D action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 3288-3297, 2017. 1", + "[20] Boeun Kim, Hyung Jin Chang, Jungho Kim, and Jin Young Choi. Global-local motion transformer for unsupervised skeleton-based action learning. In Proceedings of the European Conference on Computer Vision (ECCV), pages 209-225, 2022. 6", + "[21] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E Hinton. Imagenet classification with deep convolutional neural networks. In Proceedings of the Advances in Neural Information Processing Systems (NeurIPS), 2012. 2", + "[22] Chao Li, Qiaoyong Zhong, Di Xie, and Shiliang Pu. Skeleton-based action recognition with convolutional neural networks. In Proceedings of the IEEE International Conference on Multimedia & Expo Workshops (ICMEW), pages 597-600. IEEE, 2017. 2", + "[23] Linguo Li, Minsi Wang, Bingbing Ni, Hang Wang, Jiancheng Yang, and Wenjun Zhang. 3D human action representation learning via cross-view consistency pursuit. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4741-4750, 2021. 2, 3, 6, 7", + "[24] Maosen Li, Siheng Chen, Xu Chen, Ya Zhang, Yanfeng Wang, and Qi Tian. Actional-structural graph convolutional networks for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 3595–3603, 2019. 1", + "[25] Tianjiao Li, Qiuhong Ke, Hossein Rahmani, Rui En Ho, Henghui Ding, and Jun Liu. Else-Net: Elastic semantic network for continual action recognition from skeleton data. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13434–13443, 2021. 1", + "[26] Duohan Liang, Guoliang Fan, Guangfeng Lin, Wanjun Chen, Xiaorong Pan, and Hong Zhu. Three-stream convolutional neural network with multi-task and ensemble learning for 3D action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW), pages 934-940, 2019. 3", + "[27] Lilang Lin, Sijie Song, Wenhan Yang, and Jiaying Liu. MS2L: Multi-task self-supervised learning for skeleton based action recognition. In Proceedings of the 28th ACM International Conference on Multimedia (ACM MM), pages 2490-2498, 2020. 2, 3, 6, 7", + "[28] Jun Liu, Amir Shahroudy, Mauricio Perez, Gang Wang, Ling-Yu Duan, and Alex C Kot. NTU RGB+D 120: A large-scale benchmark for 3D human activity understanding. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 42(10):2684-2701, 2020. 2, 5", + "[29] Jun Liu, Amir Shahroudy, Dong Xu, Alex C Kot, and Gang Wang. Skeleton-based action recognition using spatio" + ], + "bbox": [ + 78, + 90, + 470, + 901 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "temporal LSTM network with trust gates. IEEE transactions on pattern analysis and machine intelligence (TPAMI), 40(12):3007-3021, 2017. 2", + "[30] Jun Liu, Amir Shahroudy, Dong Xu, and Gang Wang. Spatio-temporal LSTM with trust gates for 3D human action recognition. In Proceedings of the European Conference on Computer Vision (ECCV), pages 816-833. Springer, 2016. 2", + "[31] Xiao Liu, Fanjin Zhang, Zhenyu Hou, Li Mian, Zhaoyu Wang, Jing Zhang, and Jie Tang. Self-supervised learning: Generative or contrastive. IEEE Transactions on Knowledge and Data Engineering (TKDE), 35(1):857-876, 2023. 2", + "[32] Ziyu Liu, Hongwen Zhang, Zhenghao Chen, Zhiyong Wang, and Wanli Ouyang. Disentangling and unifying graph convolutions for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 143-152, 2020. 1, 3", + "[33] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In Proceedings of the International Conference on Learning Representations (ICLR), 2019. 5", + "[34] Yunyao Mao, Wengang Zhou, Zhenbo Lu, Jiajun Deng, and Houqiang Li. CMD: Self-supervised 3D action representation learning with cross-modal mutual distillation. In Proceedings of the European Conference on Computer Vision (ECCV), pages 734-752, 2022. 3, 6, 7", + "[35] Chiara Plizzari, Marco Cannici, and Matteo Matteucci. Skeleton-based action recognition via spatial and temporal transformer networks. Computer Vision and Image Understanding, 208:103219, 2021. 3", + "[36] Helei Qiu, Biao Hou, Bo Ren, and Xiaohua Zhang. Spatiotemporal tuples transformer for skeleton-based action recognition. arXiv preprint arXiv:2201.02849, 2022. 3", + "[37] Haocong Rao, Shihao Xu, Xiping Hu, Jun Cheng, and Bin Hu. Augmented skeleton based contrastive action learning with momentum LSTM for unsupervised action recognition. Information Sciences, 569:90-109, 2021. 6", + "[38] Amir Shahroudy, Jun Liu, Tian-Tsong Ng, and Gang Wang. NTU RGB+D: A large scale dataset for 3D human activity analysis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1010-1019, 2016. 2, 5", + "[39] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. Skeleton-based action recognition with directed graph neural networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 7912-7921, 2019. 1, 3", + "[40] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. Two-stream adaptive graph convolutional networks for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 12026-12035, 2019. 3", + "[41] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. Decoupled spatial-temporal attention network for skeleton-based action-gesture recognition. In Proceedings of the Asian Conference on Computer Vision (ACCV), 2020. 3", + "[42] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. AdaSGN: Adapting joint number and model size for efficient skeleton-based action recognition. In Proceedings of" + ], + "bbox": [ + 501, + 92, + 893, + 901 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "10190", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13413-13422, 2021. 1", + "[43] Chenyang Si, Wentao Chen, Wei Wang, Liang Wang, and Tieniu Tan. An attention enhanced graph convolutional LSTM network for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1227-1236, 2019. 1", + "[44] Chenyang Si, Xuecheng Nie, Wei Wang, Liang Wang, Tieniu Tan, and Jiashi Feng. Adversarial self-supervised learning for semi-supervised 3D action recognition. In Proceedings of the European Conference on Computer Vision (ECCV), pages 35-51, 2020. 7", + "[45] Yuxin Song, Min Yang, Wenhao Wu, Dongliang He, Fu Li, and Jingdong Wang. It takes two: Masked appearance-motion modeling for self-supervised video transformer pretraining. arXiv preprint arXiv:2210.05234, 2022. 3", + "[46] Kun Su, Xiulong Liu, and Eli Shlizerman. PREDICT & CLUSTER: Unsupervised skeleton based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 9631-9640, 2020. 2, 3, 6", + "[47] Yukun Su, Guosheng Lin, and Qingyao Wu. Self-supervised 3D skeleton action representation learning with motion consistency and continuity. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13328-13338, October 2021. 6, 7", + "[48] Fida Mohammad Thoker, Hazel Doughty, and Cees GM Snoek. Skeleton-contrastive 3D action representation learning. In Proceedings of the ACM International Conference on Multimedia (ACM MM), pages 1655–1663, 2021. 2, 3, 5, 6, 7", + "[49] Guo Tianyu, Liu Hong, Chen Zhan, Liu Mengyuan, Wang Tao, and Ding Runwei. Contrastive learning from extremely augmented skeleton sequences for self-supervised action recognition. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), 2022. 2, 3, 6, 7", + "[50] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Herve Jegou. Training data-efficient image transformers & distillation through attention. In Proceedings of the International Conference on Machine Learning (ICML), volume 139, pages 10347-10357, July 2021. 3", + "[51] Hongsong Wang and Liang Wang. Modeling temporal dynamics and spatial configurations of actions using two-stream recurrent neural networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition (CVPR), pages 499-508, 2017. 3", + "[52] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 14668-14678, 2022. 3", + "[53] Wenhan Wu, Yilei Hua, Ce zheng, Shiqian Wu, Chen Chen, and Aidong Lu. SkeletonMAE: Spatial-temporal masked autoencoders for self-supervised skeleton action recognition. arXiv preprint arXiv:2209.02399, 2022. 1, 3, 4, 6, 7, 8", + "[54] Jingwei Xu, Zhenbo Yu, Bingbing Ni, Jiancheng Yang, Xiaokang Yang, and Wenjun Zhang. Deep kinematics analysis" + ], + "bbox": [ + 78, + 92, + 468, + 900 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "for monocular 3D human pose estimation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 899-908, 2020. 1", + "[55] Sijie Yan, Yuanjun Xiong, and Dahua Lin. Spatial temporal graph convolutional networks for skeleton-based action recognition. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), pages 7444-7452, 2018. 2", + "[56] Di Yang, Yaohui Wang, Antitza Dantcheva, Lorenzo Garattoni, Gianpiero Francesca, and Francois Bremond. ViA: View-invariant skeleton action representation learning via motion retargeting. arXiv preprint arXiv:2209.00065, 2022.6,7", + "[57] Haosen Yang, Deng Huang, Bin Wen, Jiannan Wu, Hongxun Yao, Yi Jiang, Xiatian Zhu, and Zehuan Yuan. Self-supervised video representation learning with motion-aware masked autoencoders. arXiv preprint arXiv:2210.04154, 2022.3", + "[58] Siyuan Yang, Jun Liu, Shijian Lu, Meng Hwa Er, and Alex C Kot. Skeleton cloud colorization for unsupervised 3D action representation learning. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13423-13433, 2021. 2, 3, 6, 7", + "[59] Haoyuan Zhang, Yonghong Hou, Wenjing Zhang, and Wanqing Li. Contrastive positive mining for unsupervised 3D action representation learning. In Proceedings of the European Conference on Computer Vision (ECCV), pages 36-51, 2022. 3, 6, 7", + "[60] Pengfei Zhang, Cuiling Lan, Wenjun Zeng, Junliang Xing, Jianru Xue, and Nanning Zheng. Semantics-guided neural networks for efficient skeleton-based human action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1112-1121, 2020. 1", + "[61] Xikun Zhang, Chang Xu, and Dacheng Tao. Context aware graph convolution for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 14333–14342, 2020. 3", + "[62] Nenggan Zheng, Jun Wen, Risheng Liu, Liangqu Long, Jianhua Dai, and Zhefeng Gong. Unsupervised representation learning with long-term dynamics for skeleton based action recognition. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), pages 2644-2651, 2018. 2, 3, 4, 6, 7" + ], + "bbox": [ + 503, + 92, + 892, + 709 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "10191", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/06acdbbe-e15b-4021-a13d-3cb042fcaf0d_model.json b/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/06acdbbe-e15b-4021-a13d-3cb042fcaf0d_model.json new file mode 100644 index 0000000000000000000000000000000000000000..90f2049aa9d4f476040e95da2f3931fa9cf6b146 --- /dev/null +++ b/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/06acdbbe-e15b-4021-a13d-3cb042fcaf0d_model.json @@ -0,0 +1,2642 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.044 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.112, + 0.131, + 0.859, + 0.154 + ], + "angle": 0, + "content": "Masked Motion Predictors are Strong 3D Action Representation Learners" + }, + { + "type": "text", + "bbox": [ + 0.093, + 0.179, + 0.877, + 0.201 + ], + "angle": 0, + "content": "Yunyao Mao\\(^{1}\\) Jiajun Deng\\(^{3}\\) Wengang Zhou\\(^{1,2,*}\\) Yao Fang\\(^{5}\\) Wanli Ouyang\\(^{4}\\) Houqiang Li\\(^{1,2,*}\\)" + }, + { + "type": "text", + "bbox": [ + 0.108, + 0.201, + 0.865, + 0.234 + ], + "angle": 0, + "content": "\\(^{1}\\)CAS Key Laboratory of Technology in GIPAS, EEIS Department, University of Science and Technology of China \\(^{2}\\)Institute of Artificial Intelligence, Hefei Comprehensive National Science Center" + }, + { + "type": "text", + "bbox": [ + 0.107, + 0.235, + 0.865, + 0.253 + ], + "angle": 0, + "content": "3The University of Sydney 4Shanghai AI Laboratory 5Merchants Union Consumer Finance Company Limited" + }, + { + "type": "text", + "bbox": [ + 0.178, + 0.254, + 0.792, + 0.269 + ], + "angle": 0, + "content": "myy2016@mail.ustc.edu.cn, jiajun.deng@sydney.edu.au, zhwg@ustc.edu.cn" + }, + { + "type": "text", + "bbox": [ + 0.206, + 0.273, + 0.766, + 0.287 + ], + "angle": 0, + "content": "fangyao@mucfc.com, wanli.ouyang@sydney.edu.au, lihq@ustc.edu.cn" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.322, + 0.314, + 0.339 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.354, + 0.474, + 0.732 + ], + "angle": 0, + "content": "In 3D human action recognition, limited supervised data makes it challenging to fully tap into the modeling potential of powerful networks such as transformers. As a result, researchers have been actively investigating effective self-supervised pre-training strategies. In this work, we show that instead of following the prevalent pretext task to perform masked self-component reconstruction in human joints, explicit contextual motion modeling is key to the success of learning effective feature representation for 3D action recognition. Formally, we propose the Masked Motion Prediction (MAMP) framework. To be specific, the proposed MAMP takes as input the masked spatiotemporal skeleton sequence and predicts the corresponding temporal motion of the masked human joints. Considering the high temporal redundancy of the skeleton sequence, in our MAMP, the motion information also acts as an empirical semantic richness prior that guide the masking process, promoting better attention to semantically rich temporal regions. Extensive experiments on NTU-60, NTU-120, and PKU-MMD datasets show that the proposed MAMP pre-training substantially improves the performance of the adopted vanilla transformer, achieving state-of-the-art results without bells and whistles. The source code of our MAMP is available at https://github.com/maoyunyao/MAMP." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.761, + 0.21, + 0.777 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.787, + 0.47, + 0.879 + ], + "angle": 0, + "content": "How to accurately recognize human actions has been a long-standing challenge in computer vision. Recently, with the advances in techniques of depth sensing and pose estimation [3, 16, 54], skeleton-based 3D human action recognition has become an emerging problem to the community, which is of great significance in a series of applications such" + }, + { + "type": "image", + "bbox": [ + 0.522, + 0.319, + 0.692, + 0.493 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.578, + 0.498, + 0.61, + 0.509 + ], + "angle": 0, + "content": "MAE" + }, + { + "type": "image", + "bbox": [ + 0.704, + 0.319, + 0.874, + 0.492 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.736, + 0.498, + 0.816, + 0.51 + ], + "angle": 0, + "content": "MAMP (Ours)" + }, + { + "type": "image_caption", + "bbox": [ + 0.571, + 0.516, + 0.822, + 0.532 + ], + "angle": 0, + "content": "(a) Comparison of pre-training objectives." + }, + { + "type": "image", + "bbox": [ + 0.517, + 0.537, + 0.871, + 0.686 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.566, + 0.692, + 0.822, + 0.706 + ], + "angle": 0, + "content": "(b) Comparison of linear probing accuracy." + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.711, + 0.894, + 0.782 + ], + "angle": 0, + "content": "Figure 1. Illustration of (a) pre-training objective comparison between masked auto encoders (MAE) and our masked motion predictors (MAMP) and (b) performance comparison between the typical MAE method, i.e., SkeletonMAE [53], and our MAMP under the linear evaluation protocol." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.895, + 0.903 + ], + "angle": 0, + "content": "as human-computer interaction, video surveillance, virtual reality, etc. Despite the computation efficiency and background robustness of skeletons, existing supervised 3D action recognition methods [5, 7, 14, 19, 24, 25, 32, 39, 42, 43, 60] heavily rely on well-annotated training sequences, which are labor-intensive and time-consuming to acquire." + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.405, + 0.902 + ], + "angle": 0, + "content": "*Corresponding authors: Wengang Zhou and Houqiang Li" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "10181" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.168 + ], + "angle": 0, + "content": "Furthermore, limited supervision also leads to the overfitting issue in general models, especially for transformers that are with weak inductive bias and high model capacity. These facts motivate the exploration of self-supervised 3D action representation learning." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.17, + 0.468, + 0.336 + ], + "angle": 0, + "content": "In the literature, the prevalent pretext tasks originally developed for images have been adapted for 3D action representation learning, such as colorization [58], reconstruction [62, 46, 27], contrastive learning [23, 48, 49], etc. Among them, contrastive learning once dominated 3D action representation learning with its concise framework and promising performance. Nevertheless, as a global representation learner, it still suffers from certain limitations, such as the lack of explicit constraints for temporal context modeling and the over-reliance on heuristic action data augmentations [31], impeding its further exploration of 3D actions." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.34, + 0.468, + 0.596 + ], + "angle": 0, + "content": "Recently, as transformers flourish in computer vision, masked autoencoder (MAE) [17] has attracted a surge of research interest for its exceptional performance. Given that a 3D skeleton serves as an abstract representation of human behaviors, there has been growing interest in applying the MAE concept to 3D action representation learning, to capture the underlying spatio-temporal dynamics of skeleton sequences. Early attempts generally followed the practice of images, employing masked self-reconstruction of human joints as the pre-training pretext. Despite considerable effort, we argue that the network is not effectively directed to prioritize contextual motion modeling in such a self-reconstruction objective, which is, however, crucial for comprehending 3D actions as the appearance information is greatly erased in human skeletons. How to better explore the contextual motion clue in self-supervised 3D action representation learning is a valid problem." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.599, + 0.468, + 0.901 + ], + "angle": 0, + "content": "By consolidating this idea, we introduce Masked Motion Prediction (MAMP), a simple yet effective framework to address the problem of self-supervised 3D action representation learning. Specifically, the proposed MAMP takes as input the masked spatio-temporal skeleton sequence and turns to predict the corresponding temporal motion of the masked human joints. In this way, the network is directly encouraged for contextual motion modeling. Moreover, given the observation that moments with significant motion are often critical for human action understanding, in our MAMP, the temporal motion is used not only as the pretraining objective but also as an empirical semantic richness prior that effectively guiding the skeleton masking process. Compared to the random version, the proposed motion-aware masking strategy takes additional temporal motion intensity as input. It first converts the input intensity into a probability distribution and then utilizes the reparameterization technique for efficient probability-guided masked token sampling. As a result, joints with significant motion are masked with a higher probability, facilitating" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.854, + 0.107 + ], + "angle": 0, + "content": "better attention to semantically rich temporal regions." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.108, + 0.892, + 0.379 + ], + "angle": 0, + "content": "As illustrated in Figure 1, compared to masked self-reconstruction of human joints, masked motion prediction acts as a more effective pretext task for 3D action representation learning. It substantially alleviates the problem that the transformers cannot fully unleash their modeling potential for human actions due to the scarcity of annotated 3D skeletons. The adopted vanilla transformer sets a series of state-of-the-art records in 3D action recognition after MAMP pre-training, without the need for bells and whistles such as multi-stream ensembling. Specifically, compared to training from scratch, our MAMP demonstrates significant absolute performance improvements of \\(10.0\\%\\) and \\(13.2\\%\\) on the challenging cross-subject protocol of NTU RGB+D 60 [38] and NTU RGB+D 120 [28] datasets, resulting in top-1 accuracy of \\(93.1\\%\\) and \\(90.0\\%\\), respectively. We hope this simple yet effective framework will serve as a strong baseline that facilitates future research on 3D action pretraining and beyond." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.381, + 0.89, + 0.395 + ], + "angle": 0, + "content": "Overall, we make the following three-fold contributions:" + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.397, + 0.89, + 0.456 + ], + "angle": 0, + "content": "- We present masked motion prediction to learn 3D action representation, which substantially alleviates the insufficient contextual motion modeling issue in the conventional masked self-reconstruction paradigm." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.457, + 0.89, + 0.501 + ], + "angle": 0, + "content": "- We devise the motion-aware masking strategy, which incorporates motion intensity as an empirical semantic richness prior for adaptive joint masking." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.503, + 0.89, + 0.577 + ], + "angle": 0, + "content": "- We conduct extensive experiments on three prevalent benchmarks to verify the effectiveness of our method. Remarkably, with our proposed MAMP, the vanilla transformer, for the first time, achieves the top-performing record for 3D action recognition." + }, + { + "type": "list", + "bbox": [ + 0.519, + 0.397, + 0.89, + 0.577 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.594, + 0.64, + 0.609 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.62, + 0.799, + 0.636 + ], + "angle": 0, + "content": "2.1. Supervised 3D Action Recognition" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.644, + 0.892, + 0.901 + ], + "angle": 0, + "content": "How to better model the dynamic skeletons for supervised action recognition is an extensively studied problem. In many early works, RNNs are favored for their excellent sequential modeling capability, such as the hierarchical RNN model proposed in [14] and the 2D Spatio-Temporal LSTM in [30, 29]. In view of the great success of CNNs [21, 18] in image understanding, some methods also try to apply it to 3D action recognition. To cater for the input format, [13] and [22] treat the skeleton sequence as a three-channel (x, y, and z coordinates) pseudo-image, with the number of frames and joints as height and width, respectively. Considering the natural connections between joints, ST-GCN [55] introduces the Graph Neural Networks (GCNs) for skeleton modeling, where the convolution kernels are elaborately designed according to the skeleton topology. The astonishing performance of ST-GCN has led the trend of GCN-based 3D action recognition, with numer" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "10182" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.121 + ], + "angle": 0, + "content": "ous subsequent improvements emerging in input streams [51, 26, 40], kernel design [5, 61, 39, 32], etc." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.122, + 0.471, + 0.289 + ], + "angle": 0, + "content": "Recent approaches [36, 35, 41] try to introduce the popular vision transformer into 3D action recognition. However, under limited training data, vanilla transformers with weak inductive bias cannot be fully trained. Therefore, many customized designs are required in existing supervised attempts, such as temporal convolution [36], graph convolution [35, 36], space-time separation [41], etc. In our approach, we demonstrate that pre-training with masked motion prediction is key to the success of transformers in 3D action recognition. The proposed MAMP framework endows the vanilla transformer with unrivaled performance." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.299, + 0.409, + 0.315 + ], + "angle": 0, + "content": "2.2. Self-supervised 3D Action Recognition" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.323, + 0.469, + 0.502 + ], + "angle": 0, + "content": "Self-supervised representation learning aims to capture the domain priors from unlabeled data so as to facilitate the application of the model in downstream tasks. In 3D human action recognition, many pretext tasks have been utilized to explore the action context that resides in the skeleton sequence. Among them, LongT GAN [62] and P&C [46] try to learn 3D action representation by autoencoder-based sequence reconstruction, where the decoder in P&C is further weakened to promote the learning of the feature encoder. In Colorization [58], the skeleton sequences are treated as point clouds and action representation is learned by colorizing each joint based on its spatial and temporal orders." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.505, + 0.469, + 0.653 + ], + "angle": 0, + "content": "Recently, many contrastive learning-based approaches [27, 48, 23, 49, 59, 34] have emerged, showing superior performance compared to earlier works. To learn better 3D action representation, they either try to dig helpful supervision across different skeleton modalities [23, 34], or explore better action data augmentation [49] and positive sample mining strategies [59]. Nevertheless, as a global feature learner originally designed for images, contrastive learning lacks explicit constraints on the exploration of temporal motion context, limiting its further development for 3D actions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.655, + 0.469, + 0.79 + ], + "angle": 0, + "content": "SkeletonMAE [53] first introduces the idea of MAE[17] into transformer-based 3D action representation learning, where the original joint coordinates of masked regions are predicted. In our approach, we demonstrate that such a self-reconstruction objective is sub-optimal for learning 3D action representation. Therefore, we introduce the Masked Motion Prediction (MAMP) framework for explicit contextual motion modeling, resulting in significantly better performance compared to raw skeleton reconstruction." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.802, + 0.312, + 0.817 + ], + "angle": 0, + "content": "2.3. Masked Visual Prediction" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.825, + 0.469, + 0.901 + ], + "angle": 0, + "content": "With the development of vision transformers [4, 12, 50], the masked prediction derived from the autoencoder [1] has revived again. Similar to the BERT [11] pre-training in NLP, the input tokens are randomly masked and corresponding objectives are predicted, which can be the raw" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.333 + ], + "angle": 0, + "content": "pixels [17], HOG features [52], or token ids from offline learned dVAEs [2]. Recently, there have also been attempts [45, 57] to use optical flow or temporal difference of images as the auxiliary reconstruction objectives, but inferior performance is observed when they are applied alone. This is largely attributed to the high redundancy of the raw images, where the key foreground motion is difficult to be pre-extracted accurately. In our approach, we employ the idea of masked visual prediction for 3D action representation learning, with the temporal skeleton motion adopted as the only reconstruction target. Different from images, the explicit temporal correspondence of joints in the human skeleton sequence enables the ready extraction of their accurate motion context. Furthermore, we also incorporate motion intensity as the semantic richness prior to guide the masking process." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.348, + 0.63, + 0.364 + ], + "angle": 0, + "content": "3. Our Method" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.374, + 0.61, + 0.388 + ], + "angle": 0, + "content": "3.1. Overview" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.397, + 0.892, + 0.533 + ], + "angle": 0, + "content": "Figure 2 illustrates the overall pipeline of our proposed Masked Motion Prediction (MAMP) framework. It takes a skeleton sequence \\( S \\in \\mathbb{R}^{T_s \\times V \\times C_s} \\) as input, which is randomly cropped from the original data and is resized to a fixed temporal length \\( T_s \\). \\( V \\) and \\( C_s \\) are the number of joints and coordinate channels, respectively. The motion sequence \\( M \\in \\mathbb{R}^{T_s \\times V \\times C_s} \\) of the input is also extracted, which is defined as the differential on temporal dimension (manually padded for the first frame)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.534, + 0.892, + 0.744 + ], + "angle": 0, + "content": "As in most vision transformers, the input joints are linearly mapped into joint embedding \\( E \\in \\mathbb{R}^{T_e \\times V \\times C_e} \\). After that, the motion-aware masking strategy is applied to mask most of the embedding features under the guidance of temporal motion intensity. The remaining features are processed by the encoder-decoder architecture, where the transformer encoder learns representation from unmasked joint embedding and the transformer decoder performs contextual modeling based on the learnable mask tokens and latent representation from the transformer encoder. Different from MAE [17] that reconstructs the original signal for representation learning, in MAMP, a motion prediction head is adopted, which takes decoded features as input and predicts the temporal motion of the input skeleton sequence." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.746, + 0.892, + 0.791 + ], + "angle": 0, + "content": "After the aforementioned pre-training, only the joint embedding layer and the transformer encoder are reserved for downstream applications." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.802, + 0.669, + 0.817 + ], + "angle": 0, + "content": "3.2. Joint Embedding" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "In most transformer-based attempts [35, 41, 36], each spatio-temporal skeleton joint is embedded separately, resulting in a large number of input tokens. Considering the temporal redundancy, in our approach, the input skeleton sequence \\( S \\in \\mathbb{R}^{T_s \\times V \\times C_s} \\) is divided into temporally non" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "10183" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.089, + 0.895, + 0.271 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.275, + 0.895, + 0.332 + ], + "angle": 0, + "content": "Figure 2. The overall pipeline of the proposed MAMP framework. Different from the self-reconstruction scheme adopted in previous works [62, 53], our MAMP learns 3D action representation by predicting the corresponding motion sequence for masked joint input. Moreover, motion information also acts as an empirical semantic richness prior that effectively guides the masking process, enabling more attention to be applied to regions with significant temporal motion intensity." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.357, + 0.47, + 0.404 + ], + "angle": 0, + "content": "overlapping segments \\( S' \\in \\mathbb{R}^{T_e \\times V \\times l \\times C_s} \\), where \\( l \\) is the length of each segment and \\( T_e = T_s / l \\). In each segment, joints with the same spatial position are embedded together:" + }, + { + "type": "equation", + "bbox": [ + 0.141, + 0.416, + 0.469, + 0.435 + ], + "angle": 0, + "content": "\\[\nE = \\operatorname {J o i n t E m b e d} \\left(S ^ {\\prime}\\right) \\in \\mathbb {R} ^ {T _ {e} \\times V \\times C _ {e}}, \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.44, + 0.47, + 0.502 + ], + "angle": 0, + "content": "where \\( C_e \\) is the dimension of the embedding features. Compared to the original skeleton sequence, the temporal resolution of the embedding \\( E \\) is reduced by a factor of \\( l \\), resulting in higher computational efficiency." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.51, + 0.258, + 0.525 + ], + "angle": 0, + "content": "3.3. Motion Extraction" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.534, + 0.469, + 0.61 + ], + "angle": 0, + "content": "Different from RGB frames with heavy spatial redundancy, the human skeleton sequence is highly semantic, with explicit correspondence between neighboring frames. Therefore, we can easily obtain its motion \\( M \\in \\mathbb{R}^{T_s \\times V \\times C_s} \\) by applying temporal difference on joint coordinates:" + }, + { + "type": "equation", + "bbox": [ + 0.088, + 0.621, + 0.469, + 0.639 + ], + "angle": 0, + "content": "\\[\nM _ {i,:,:} = S _ {i,:,:} - S _ {i - m,:,:}, i \\in m, m + 1, \\dots , T _ {s} - 1, \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.649, + 0.47, + 0.695 + ], + "angle": 0, + "content": "where stride \\(m\\) controls the step size of the motion. For convenience, the motion sequence is padded to be consistent with the length of the original input:" + }, + { + "type": "equation", + "bbox": [ + 0.124, + 0.705, + 0.469, + 0.737 + ], + "angle": 0, + "content": "\\[\nM _ {0: m - 1,:,:} = \\left\\{ \\begin{array}{l l} 0, & \\text {c o n s t a n t} \\\\ M _ {m: 2 m - 1,:,:}, & \\text {r e p l i c a t e} \\end{array} , \\right. \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.748, + 0.47, + 0.793 + ], + "angle": 0, + "content": "where constant and replicate denote constant padding (with zeros) and replicate padding for the first \\(m\\) frames of the motion sequence, respectively." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.802, + 0.296, + 0.818 + ], + "angle": 0, + "content": "3.4. Motion-Aware Masking" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.826, + 0.47, + 0.902 + ], + "angle": 0, + "content": "In the proposed approach, the motion information is used not only as the reconstruction target during pre-training but also as the empirical semantic richness prior that guiding the masking of embedding features. Considering that the skeleton sequence is segment-wise embedded with length \\(l\\)," + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.357, + 0.892, + 0.448 + ], + "angle": 0, + "content": "we extract the motion sequence \\( M^{\\mathrm{mask}} \\in \\mathbb{R}^{T_i \\times V \\times C_i} \\) with stride \\( m = l \\) and replicate padding according to Eq. (2) and Eq. (3), which is further reshaped into \\( M' \\in \\mathbb{R}^{T_e \\times V \\times l \\times C_i} \\) as is done for \\( S' \\). Then, the motion intensity \\( I \\), which indicates the motion significance of each spatio-temporal segment, is computed as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.588, + 0.456, + 0.892, + 0.5 + ], + "angle": 0, + "content": "\\[\nI = \\sum_ {i = 0} ^ {l} \\sum_ {j = 0} ^ {C _ {i}} \\left| M _ {:,:,: i, j} ^ {\\prime} \\right| \\in \\mathbb {R} ^ {T _ {e} \\times V}. \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.508, + 0.892, + 0.584 + ], + "angle": 0, + "content": "Since human actions are composed of a series of temporal movements, we argue that the intensity of motion largely reflects the semantic richness. Therefore in MAMP, the motion intensity is further converted into probability distribution with a temperature hyper-parameter \\(\\tau\\):" + }, + { + "type": "equation", + "bbox": [ + 0.621, + 0.593, + 0.891, + 0.61 + ], + "angle": 0, + "content": "\\[\n\\pi = \\operatorname {S o f t m a x} (I / \\tau), \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.618, + 0.892, + 0.664 + ], + "angle": 0, + "content": "which indicates the probability that each embedding feature is masked. In MAMP, the idea of gumble max is adapted for efficient probability-guided mask index sampling:" + }, + { + "type": "equation", + "bbox": [ + 0.552, + 0.671, + 0.891, + 0.71 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} g = - \\log (- \\log \\epsilon), \\epsilon \\in U [ 0, 1 ] ^ {T _ {\\epsilon} \\times V}, \\\\ i d x ^ {\\text {m a s k}} = \\text {I n d e x - o f - T o p - K} (\\log \\pi + g), \\tag {6} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.718, + 0.892, + 0.809 + ], + "angle": 0, + "content": "where \\( U[0,1] \\) denotes uniform distribution between 0 and 1. The obtained \\( idx^{\\mathrm{mask}} \\) indicates which joints are masked and is used for unmasked token selection in Section 3.5. Based on the above operations, the network is encouraged to focus more on semantically rich regions, so as to learn more discriminative 3D action representation." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.818, + 0.742, + 0.832 + ], + "angle": 0, + "content": "3.5. Masked Motion Prediction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.902 + ], + "angle": 0, + "content": "We follow the encoder-decoder design in MAE [17], where the transformer encoder focuses on representation learning, while the decoder is responsible for the implementation of the pre-training pretext." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "10184" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.152 + ], + "angle": 0, + "content": "Encoder: In the encoder, separate spatio-temporal positional embedding \\( P_{e}^{s} \\in \\mathbb{R}^{1 \\times V \\times C_{e}} \\) and \\( P_{e}^{t} \\in \\mathbb{R}^{T_{e} \\times 1 \\times C_{e}} \\) are first element-wise added (with broadcasting) to the input joint embedding \\( E \\):" + }, + { + "type": "equation", + "bbox": [ + 0.202, + 0.158, + 0.469, + 0.175 + ], + "angle": 0, + "content": "\\[\nE _ {p} = E + P _ {e} ^ {s} + P _ {e} ^ {t}. \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.181, + 0.469, + 0.256 + ], + "angle": 0, + "content": "Then, the unmasked tokens in \\( E_{p} \\) are selected according to the \\( idx^{\\mathrm{mask}} \\) extracted in Eq. (6) and are flattened to \\( E_{p}^{u} \\in \\mathbb{R}^{N_{u} \\times C_{e}} \\), where \\( N_{u} = T_{e} \\times V \\times (1 - \\mathrm{mask~ratio}) \\) is the number of unmasked tokens. After that, the latent representation is extracted by \\( L_{e} \\) vanilla transformer blocks:" + }, + { + "type": "equation", + "bbox": [ + 0.103, + 0.262, + 0.177, + 0.28 + ], + "angle": 0, + "content": "\\[\nH _ {0} = E _ {p} ^ {u},\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.107, + 0.282, + 0.469, + 0.306 + ], + "angle": 0, + "content": "\\[\nH _ {l} ^ {\\prime} = \\operatorname {M S A} \\left(\\ln \\left(H _ {l - 1}\\right)\\right) + H _ {l - 1}, \\quad l \\in 1, \\dots , L _ {e} \\tag {8}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.107, + 0.301, + 0.453, + 0.318 + ], + "angle": 0, + "content": "\\[\nH _ {l} = \\operatorname {M L P} \\left(\\operatorname {L N} \\left(H _ {l} ^ {\\prime}\\right)\\right) + H _ {l} ^ {\\prime}, \\quad l \\in 1, \\dots , L _ {e}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.103, + 0.321, + 0.218, + 0.337 + ], + "angle": 0, + "content": "\\[\nH _ {e} ^ {u} = \\mathrm {L N} \\left(H _ {L _ {e}}\\right),\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.342, + 0.468, + 0.372 + ], + "angle": 0, + "content": "where MSA, MLP, and LN denote multi-head self-attention, multilayer perceptron, and layer norm, respectively." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.372, + 0.469, + 0.433 + ], + "angle": 0, + "content": "Decoder: In the decoder, the learnable mask tokens are inserted into \\( H_{e}^{u} \\) according to the mask indices \\( idx^{\\mathrm{mask}} \\). The result is reshaped back to \\( H_{e} \\in \\mathbb{R}^{T_{e} \\times V \\times C_{e}} \\), which is processed by \\( L_{d} \\) decoder layers for masked modeling:" + }, + { + "type": "equation", + "bbox": [ + 0.106, + 0.438, + 0.255, + 0.455 + ], + "angle": 0, + "content": "\\[\nZ _ {0} = H _ {e} + P _ {d} ^ {s} + P _ {d} ^ {t},\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.109, + 0.457, + 0.469, + 0.482 + ], + "angle": 0, + "content": "\\[\nZ _ {l} ^ {\\prime} = \\operatorname {M S A} \\left(\\ln \\left(Z _ {l - 1}\\right)\\right) + Z _ {l - 1}, \\quad l \\in 1, \\dots , L _ {d} \\tag {9}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.109, + 0.476, + 0.469, + 0.493 + ], + "angle": 0, + "content": "\\[\nZ _ {l} = \\operatorname {M L P} \\left(\\ln \\left(Z _ {l} ^ {\\prime}\\right)\\right) + Z _ {l} ^ {\\prime}, \\quad l \\in 1, \\dots , L _ {d}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.108, + 0.495, + 0.215, + 0.512 + ], + "angle": 0, + "content": "\\[\nZ _ {d} = \\operatorname {L N} \\left(Z _ {L _ {d}}\\right),\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.518, + 0.469, + 0.548 + ], + "angle": 0, + "content": "where \\(P_{d}^{s}\\) and \\(P_{d}^{t}\\) are the spatial and temporal positional embedding of the transformer decoder, respectively." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.549, + 0.469, + 0.655 + ], + "angle": 0, + "content": "Motion Prediction: In our method, the reconstruction target is not the original skeletons, but the motion sequence \\( M^{\\mathrm{target}} \\) pre-extracted according to Eq. (2) and Eq. (3), which is normalized by its segment-wise mean and standard deviation as in [17]. Therefore, given the decoded feature \\( Z_{d} \\in \\mathbb{R}^{T_{e} \\times V \\times C_{d}} \\), we additionally adopt a prediction head to predict the temporal motion of masked human joints:" + }, + { + "type": "equation", + "bbox": [ + 0.154, + 0.66, + 0.469, + 0.677 + ], + "angle": 0, + "content": "\\[\nM ^ {\\text {p r e d}} = \\text {M o t i o n P r e d H e a d} \\left(Z _ {d}\\right), \\tag {10}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.683, + 0.469, + 0.744 + ], + "angle": 0, + "content": "where we empirically find that a simple fully connected layer just works well. For masked human joints, we compute the mean squared error (MSE) between the predicted result \\( M^{\\mathrm{pred}} \\) and the reconstruction target \\( M^{\\mathrm{target}} \\):" + }, + { + "type": "equation", + "bbox": [ + 0.1, + 0.749, + 0.469, + 0.786 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} = \\frac {1}{| i d x ^ {\\text {m a s k}} |} \\sum_ {(i, j) \\in i d x ^ {\\text {m a s k}}} \\| \\left(M _ {i, j,:} ^ {\\text {p r e d}} - M _ {i, j,:} ^ {\\text {t a r g e t}}\\right) \\| _ {2} ^ {2}. \\tag {11}\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.793, + 0.209, + 0.809 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.817, + 0.377, + 0.832 + ], + "angle": 0, + "content": "4.1. Datasets and Evaluation Protocols" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.469, + 0.901 + ], + "angle": 0, + "content": "NTU-RGB+D 60 [38]: NTU-RGB+D 60 (NTU-60) is a large-scale dataset for human action recognition. It contains 60 action categories performed by 40 different subjects, with a total of 56,880 3D skeleton sequences. In this" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.197 + ], + "angle": 0, + "content": "paper, we adopt the evaluation protocols recommended by the authors, namely cross-subject (X-sub) and cross-view (X-view). The former, X-sub uses the action sequences performed by half of the 40 subjects as training samples and the rest as test samples. For X-view, the training samples are action sequences captured by cameras 2 and 3, and the test samples are those captured by camera 1." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.198, + 0.892, + 0.363 + ], + "angle": 0, + "content": "NTU-RGB+D 120 [28]: NTU-RGB+D 120 (NTU120) is an extended version of NTU-60, in which the number of action categories is increased from 60 to 120, the number of total skeleton sequences and subjects are also increased to 114,480 and 106, respectively. Furthermore, the authors also introduce a more challenging evaluation protocol named cross-setup (X-set) to substitute for the original X-view in NTU-60. Specifically, X-set divides sequences into 32 different setups based on the camera distance and background. Samples from half of these setups are used as the training set and the remainder constitute the test set." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.365, + 0.892, + 0.516 + ], + "angle": 0, + "content": "PKU-MMD [9]: Following [48], to perform 3D action classification on PKU-MMD, we crop out action instances based on temporal annotations and divide them into training and test sets according to the cross-subject protocol. PKU-MMD contains two phases: PKU-MMD I (PKU-I) and PKU-MMD II (PKU-II). In PKU-I, the number of samples in training and test sets are 18,841 and 2,704, respectively. Due to the more noise introduced by the larger view variation, PKU-II is more challenging, with 5,332 samples for training and 1,613 for testing." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.528, + 0.691, + 0.544 + ], + "angle": 0, + "content": "4.2. Experimental Setup" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.552, + 0.892, + 0.718 + ], + "angle": 0, + "content": "Network Architecture: In our MAMP framework, we adopt a vanilla vision transformer [12] as the backbone network, which consists of \\( L_{e} = 8 \\) identical building blocks. In each block, the embedding dimension is 256, the head number of the multi-head self-attention module is 8, and the hidden dimension of the feed-forward network is 1024. We employ learnable spatio-temporal separated positional embedding to the embedded inputs. The settings of the transformer decoder used during pre-training are consistent with those of the backbone encoder except that the number of layers \\( L_{d} \\) is reduced to 5." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.719, + 0.892, + 0.809 + ], + "angle": 0, + "content": "Data Processing Details: Given an original skeleton sequence, a contiguous segment is first randomly cropped from it with a certain proportion \\( p \\) (\\( p \\) is sampled from [0.5,1] during training and fixed to 0.9 during the test). After that, the cropped segment is resized to a fixed length \\( T_{s} \\) by bilinear interpolation. \\( T_{s} \\) is set to 120 by default." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Pre-training Details: During pre-training, the masking ratio of the input token is set to \\(90\\%\\). The target motion sequence \\(M^{\\mathrm{target}}\\) has stride \\(m = 1\\) and is padded with zeros. We adopt the AdamW [33] optimizer with a weight decay of 0.05 and betas of (0.9, 0.95). We pre-train the network for 400 epochs with a batch size of 128. The learning rate" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "10185" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.081, + 0.089, + 0.887, + 0.322 + ], + "angle": 0, + "content": "
MethodInput streamNTU-60NTU-120PKU-MMD
X-subX-viewX-subX-setPhase IPhase II
3s-SkeletonCLR [23]Joint+Motion+Bone75.079.860.762.685.3-
3s-CrosSCLR [23]Joint+Motion+Bone77.883.467.966.784.921.2
3s-AimCLR [49]Joint+Motion+Bone78.983.868.268.887.439.5
LongT GAN [62]Joint only39.148.1--67.726.0
P&C [46]Joint only50.776.342.741.759.925.5
MS2L [27]Joint only52.6---64.927.6
AS-CAL [37]Joint only58.564.848.649.2--
ISC [48]Joint only76.385.267.167.980.936.0
GL-Transformer [20]Joint only76.383.866.068.7--
CPM [59]Joint only78.784.968.769.688.848.3
CMD [34]Joint only79.486.970.371.5-43.0
SkeletonMAE* [53]Joint only74.877.772.573.582.836.1
MAMP (Ours)Joint only84.989.178.679.192.253.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.325, + 0.893, + 0.355 + ], + "angle": 0, + "content": "Table 1. Performance comparison on the NTU-60, NTU-120, and PKU-MMD datasets under the linear evaluation protocol. * indicates the re-implemented version under our framework, where improved performance is achieved." + }, + { + "type": "table", + "bbox": [ + 0.081, + 0.368, + 0.462, + 0.599 + ], + "angle": 0, + "content": "
MethodBackboneNTU-60
X-subX-view
CPM [59]ST-GCN84.891.1
CrossCLR [23]3s-ST-GCN86.292.5
AimCLR [49]3s-ST-GCN86.992.8
CrossCLR [23]STTFormer84.690.5
AimCLR [49]STTFormer83.990.4
SkeletonMAE [53]STTFormer86.692.9
Colorization [58]3s-DGCNN88.094.9
MCC [47]2s-AGCN89.796.3
ViA [56]2s-UINK89.696.4
Hi-TRS [6]3s-Transformer90.095.7
W/o pre-trainingTransformer83.192.6
SkeletonMAE* [53]Transformer88.594.7
MAMP (Ours)Transformer93.197.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.603, + 0.47, + 0.632 + ], + "angle": 0, + "content": "Table 2. Performance comparison on the NTU-60 dataset under the fine-tuned evaluation protocol." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.657, + 0.469, + 0.718 + ], + "angle": 0, + "content": "is linearly increased to 1e-3 from 0 in the first 20 warm-up epochs and then decreased to 5e-4 by the cosine decay schedule. The experiments are conducted using the PyTorch framework on four NVIDIA RTX 3090 GPUs." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.727, + 0.442, + 0.743 + ], + "angle": 0, + "content": "4.3. Comparison with State-of-the-art Methods" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Linear Evaluation Results: In linear evaluation protocol, the pre-trained backbone is fixed and a post-attached linear classifier is trained with supervision for 100 epochs with a batch size of 256 and a learning rate of 0.1. The learning rate is decreased to 0 by the cosine decay schedule. As shown in Table 1, the performance on three datasets are reported, they are NTU-60, NTU-120, and PKU-MMD, respectively. We include latest high-performance approaches for comparison, e.g., GL-Transformer [20], CPM [59], CMD [34], 3s-CrosSLR [23], and 3s-AimCLR [49]. As" + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.368, + 0.885, + 0.584 + ], + "angle": 0, + "content": "
MethodBackboneNTU-120
X-subX-set
CPM [59]ST-GCN78.478.9
CrosCLR [23]3s-ST-GCN80.580.4
AimCLR [49]3s-ST-GCN80.180.9
CrosCLR [23]STTFormer75.077.9
AimCLR [49]STTFormer74.677.2
SkeletonMAE [53]STTFormer76.879.1
MCC [47]2s-AGCN81.383.3
ViA [56]2s-UINK85.086.5
Hi-TRS [6]3s-Transformer85.387.4
W/o pre-trainingTransformer76.879.7
SkeletonMAE* [53]Transformer87.088.9
MAMP (Ours)Transformer90.091.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.588, + 0.892, + 0.618 + ], + "angle": 0, + "content": "Table 3. Performance comparison on the NTU-120 dataset under the fine-tuned evaluation protocol." + }, + { + "type": "table", + "bbox": [ + 0.507, + 0.636, + 0.882, + 0.732 + ], + "angle": 0, + "content": "
MethodNTU-60NTU-120
X-subX-viewX-subX-set
PoseC3D [15]93.796.686.089.6
CTR-CGN [5]92.496.888.990.6
InfoGCN [8]93.097.189.891.2
MAMP (Ours)93.197.590.091.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.736, + 0.892, + 0.779 + ], + "angle": 0, + "content": "Table 4. Performance comparison with fully-supervised methods on the NTU-60 and NTU-120 datasets. Note that our MAMP does not perform multi-stream ensembling during evaluation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.892, + 0.901 + ], + "angle": 0, + "content": "we can see, with the joint stream as the only input, our proposed MAMP outperforms these methods on all the datasets. Specifically, MAMP outperforms previous state-of-the-art method CMD by \\(5.5\\%\\) and \\(8.3\\%\\) on the challenging NTU-60 x-sub and NTU-120 x-sub, respectively. For a fair comparison, we also re-implement the Skeleton" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "10186" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.091, + 0.471, + 0.182 + ], + "angle": 0, + "content": "MAE [53] under the same settings as our approach (denote as SkeletonMAE*), where improved performance is achieved. We can find that our MAMP significantly outperforms SkeletonMAE* on all six subsets of the three datasets, demonstrating the superiority of masked motion prediction compared to the self-reconstruction of joints." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.184, + 0.474, + 0.502 + ], + "angle": 0, + "content": "Fine-tuned Evaluation Results: In fine-tuned evaluation protocol, an MLP head is attached to the pre-trained backbone and the whole network is fully fine-tuned for 100 epochs with a batch size of 48. The learning rate is linearly increased to 3e-4 from 0 in the first 5 warm-up epochs and then decreased to 1e-5 by the cosine decay schedule. We also adopt layer-wise lr decay [10] following [2]. As shown in Table 2 and Table 3, we evaluate the fine-tuned performance on NTU-60 and NTU-120, respectively. The vanilla transformer does not show satisfactory performance when trained directly from scratch, which is under expectation as weakly biased transformers require a large amount of training data to effectively prevent overfitting. After being pre-trained with the proposed MAMP framework, the network exhibits significant performance improvements ranging from \\(5\\%\\) to \\(13\\%\\) on the four subsets of the NTU-60 and NTU-120 datasets. The final results exceed all previous methods, even those with multi-stream ensembling such as Colorization [58], MCC [47], and ViA [56]. Moreover, our MAMP also outperforms the re-implemented Skeleton-MAE* by a considerable margin." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.504, + 0.47, + 0.579 + ], + "angle": 0, + "content": "We also compare our MAMP with the top-performing supervised methods like PoseC3D [15], CTR-GCN [5], and InfoGCN [8] in Table 4. Results show that without ensembling, MAMP outperforms most top-performing methods, especially on the larger NTU-120 dataset." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.582, + 0.472, + 0.852 + ], + "angle": 0, + "content": "Semi-supervised Evaluation Results: Following previous works [23, 34, 48], in semi-supervised evaluation protocol, the post-attached classification layer and the pre-trained encoder are fine-tuned together with only a small fraction of the training set. Apart from that, we keep other training settings consistent with the fine-tuned evaluation protocol. As in [23, 49, 59], we report the performance on the NTU-60 dataset when using \\(1\\%\\) and \\(10\\%\\) of the training set. Note that considering the randomness during training data selection, we report the average of five runs as the final results. As shown in Table 5, our proposed MAMP significantly outperforms previous works like 3s-AimCLR [49], CPM [59], CMD [34], and SkeletonMAE* [53]. When using only \\(1\\%\\) of the training data, MAMP outperforms SkeletonMAE* by \\(11.6\\%\\) and \\(14.0\\%\\) in X-sub and X-view respectively. Compared to training from scratch, MAMP pretraining brings performance improvements of more than \\(15.5\\%\\) on all subsets of NTU-60." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Transfer Learning Evaluation Results: In transfer learning evaluation protocol, the network is pre-trained on a source dataset and then finetuned on a different target" + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.089, + 0.887, + 0.352 + ], + "angle": 0, + "content": "
MethodNTU-60
X-subX-view
(1%)(10%)(1%)(10%)
LongT GAN [62]35.262.0--
MS2L [27]33.165.1--
ASSL [44]-64.3-69.8
ISC [48]35.765.938.172.5
3s-CrosSCLR [23]51.174.450.077.8
3s-Colorization [58]48.371.752.578.9
CMD [34]50.675.453.080.2
3s-Hi-TRS [6]49.377.751.581.1
3s-AimCLR [49]54.878.254.381.6
3s-CMD [34]55.679.055.582.4
CPM [59]56.773.057.577.1
W/o pre-training38.870.840.476.0
SkeletonMAE* [53]54.480.654.683.5
MAMP (Ours)66.088.068.791.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.356, + 0.895, + 0.398 + ], + "angle": 0, + "content": "Table 5. Performance comparison on the NTU-60 dataset under the semi-supervised evaluation protocol. We report the average of five runs as the final performance." + }, + { + "type": "table", + "bbox": [ + 0.504, + 0.411, + 0.887, + 0.539 + ], + "angle": 0, + "content": "
MethodTo PKU-II
NTU-60NTU-120PKU-I
LongT GAN [62]44.8-43.6
MS²L [27]45.8-44.1
ISC [48]51.152.345.1
CMD [34]56.057.0-
SkeletonMAE* [53]58.461.062.5
MAMP (Ours)70.673.270.1
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.542, + 0.895, + 0.584 + ], + "angle": 0, + "content": "Table 6. Performance comparison on the PKU-II dataset under the transfer learning evaluation protocol. The source datasets are the NTU-60, NTU-120, and PKU-I datasets." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.611, + 0.895, + 0.749 + ], + "angle": 0, + "content": "dataset. In this way, the generalizability of the learned representation is verified. In this paper, the target dataset is PKU-MMD II and the source datasets are NTU-60, NTU-120, and PKU-MMD I, respectively. Results in Table 6 show that, compared to previous methods, the representation learned by our proposed MAMP framework exhibits the best transferability, outperforming the reproduced SkeletonMAE* [53] by \\(12.2\\%\\), \\(12.2\\%\\), and \\(7.6\\%\\) on the three source datasets, respectively." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.756, + 0.655, + 0.773 + ], + "angle": 0, + "content": "4.4. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Superiority of Masked Motion Prediction: As shown in Table 7, to verify the superiority of masked motion prediction, we designed four different ablative experiments. Given the joint and motion streams of the original data, all possible choices of the model input and reconstruction target are traversed. We can find that our joint-to-motion prediction significantly outperforms other strategies. Under the linear evaluation protocol, our MAMP exceeds joint-to-joint pre" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "10187" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.09, + 0.089, + 0.348, + 0.218 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.088, + 0.222, + 0.348, + 0.279 + ], + "angle": 0, + "content": "Figure 3. Pre-training loss plot. Compared to masked self-reconstruction of joints in SkeletonMAE, masked motion prediction acts as a harder pre-training objective." + }, + { + "type": "image", + "bbox": [ + 0.357, + 0.089, + 0.616, + 0.219 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.356, + 0.222, + 0.615, + 0.278 + ], + "angle": 0, + "content": "Figure 4. Ablation study on the masking ratio. The performance is evaluated on the NTU-60 X-sub dataset under the linear evaluation protocol." + }, + { + "type": "image", + "bbox": [ + 0.626, + 0.088, + 0.885, + 0.218 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.624, + 0.222, + 0.882, + 0.278 + ], + "angle": 0, + "content": "Figure 5. Pre-training schedule of SkeletonMAE and our MAMP. The performance is evaluated on the NTU-60 X-sub dataset under the linear evaluation protocol." + }, + { + "type": "table", + "bbox": [ + 0.097, + 0.301, + 0.449, + 0.384 + ], + "angle": 0, + "content": "
InputTargetNTU-60NTU-120
JointJoint74.872.5
Motion84.978.6
MotionJoint76.571.0
Motion75.970.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.387, + 0.47, + 0.43 + ], + "angle": 0, + "content": "Table 7. Ablation study on the superiority of masked motion prediction. The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol." + }, + { + "type": "table", + "bbox": [ + 0.096, + 0.443, + 0.449, + 0.495 + ], + "angle": 0, + "content": "
StrategyNTU-60NTU-120
Random masking83.777.3
Motion-aware masking84.978.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.497, + 0.47, + 0.54 + ], + "angle": 0, + "content": "Table 8. Ablation study on the mask sampling strategy. The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.567, + 0.469, + 0.627 + ], + "angle": 0, + "content": "dition (adopted by [53]) by \\(10.1\\%\\) and \\(6.1\\%\\) on NTU-60 and NTU-120, respectively. This suggests that predicting dynamic motion from static skeletons during pre-training facilitates better contextual modeling of 3D human actions." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.628, + 0.469, + 0.674 + ], + "angle": 0, + "content": "We also visualize the pre-training loss in Figure 3. Unlike the fast convergence of SkeletonMAE, masked motion prediction serves as a much harder pre-training objective." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.674, + 0.469, + 0.84 + ], + "angle": 0, + "content": "Mask Sampling Strategy: In our approach, we employ the vanilla transformer as the backbone network, where embedding features at any spatio-temporal location can be freely masked as in MAE [17]. To verify the effectiveness of the proposed motion-aware masking strategy, we compare its performance with that of random masking in Table 8. As we can see, our motion-aware masking strategy brings absolute performance improvements of \\(1.2\\%\\) and \\(1.3\\%\\) on NTU-60 and NTU-120, respectively. This suggests that the motion information, as an empirical semantic richness prior, can effectively guide the skeleton masking process." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Segment Length: We evaluated the performance of the learned representation under different segment lengths \\( l \\) used in the joint embedding process. For a fair comparison, we resize the original input sequence to ensure that the" + }, + { + "type": "table", + "bbox": [ + 0.534, + 0.301, + 0.859, + 0.383 + ], + "angle": 0, + "content": "
Te=Ts/lTslNTU-60NTU-120
3060284.677.8
120484.978.6
180683.378.6
240884.577.9
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.386, + 0.893, + 0.457 + ], + "angle": 0, + "content": "Table 9. Ablation study on the segment length \\( l \\) used in the joint embedding process. For a fair comparison, the input length \\( T_{s} \\) is adjusted to ensure that the embedded features have a fixed length \\( T_{e} \\). The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol." + }, + { + "type": "table", + "bbox": [ + 0.513, + 0.469, + 0.687, + 0.552 + ], + "angle": 0, + "content": "
LdNTU-60NTU-120
283.377.2
384.977.6
484.677.5
584.978.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.541, + 0.557, + 0.655, + 0.571 + ], + "angle": 0, + "content": "(a) Decoder depth." + }, + { + "type": "table", + "bbox": [ + 0.703, + 0.469, + 0.881, + 0.552 + ], + "angle": 0, + "content": "
CdNTU-60NTU-120
6482.374.2
12883.577.3
25684.978.6
51284.577.1
" + }, + { + "type": "table_caption", + "bbox": [ + 0.734, + 0.557, + 0.848, + 0.57 + ], + "angle": 0, + "content": "(b) Decoder width." + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.575, + 0.892, + 0.618 + ], + "angle": 0, + "content": "Table 10. Ablation study on the decoder design. The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.644, + 0.892, + 0.689 + ], + "angle": 0, + "content": "embedded features have a fixed length \\( T_{e} = T_{s} / l = 30 \\). As shown in Table 9, a segment length of 4 brings the best performance on both NTU-60 and NTU-120 datasets." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.689, + 0.892, + 0.825 + ], + "angle": 0, + "content": "Decoder Design: We experimented with different numbers of layers and widths (feature dimensions) for the transformer decoder. As shown in Table 10 (a), our MAMP exhibits the best performance on the NTU-60 and NTU-120 datasets when the number of decoder layers is 3 and 5, respectively. The experimental results of the decoder width are in Table 10 (b), where a width of 256 brings the best performance. Overall, a decoder with 5 layers and a width of 256 is adopted in our MAMP framework by default." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Masking Ratio: As shown in Figure 4, we experimented with different masking ratios. Results on NTU-60 X-sub show that either too large or too small masking ratios have a negative impact on performance. We empirically found that a masking ratio of \\(90\\%\\) exhibits the best results." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "10188" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.214 + ], + "angle": 0, + "content": "Pre-training Schedule: We studied the influence of the pre-training schedule length. As shown in Figure 5, both SkeletonMAE and our MAMP exhibit higher performance with longer pre-training schedules. It is worth mentioning that our MAMP significantly outperforms SkeletonMAE for all pre-training schedules with lengths ranging from 80 to 400 epochs, demonstrating the stability and superiority of the proposed masked motion prediction strategy." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.225, + 0.196, + 0.241 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.25, + 0.473, + 0.493 + ], + "angle": 0, + "content": "In this work, we present MAMP, a simple yet effective framework for 3D action representation learning. We show that compared to conventional masked self-reconstruction of human joints, masked joint-to-motion prediction is demonstrated to be more effective for contextual motion modeling of 3D human actions. Given the high temporal redundancy of the skeleton sequence, we further devise the motion-aware masking strategy, which incorporates motion intensity as the empirical semantic richness prior for adaptive skeleton masking, facilitating better attention to semantically rich temporal regions. We conduct extensive experiments on three prevalent benchmarks under four evaluation protocols. Results show that the proposed MAMP brings remarkable performance improvements and sets a series of new state-of-the-art records, unleashing the tremendous potential of vanilla transformers for 3D action modeling." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.507, + 0.471, + 0.584 + ], + "angle": 0, + "content": "Acknowledgement: This work was supported by NSFC under Contract U20A20183 & 61836011. It was also supported by the GPU cluster built by MCC Lab of Information Science and Technology Institution, USTC, and the Supercomputing Center of the USTC." + }, + { + "type": "title", + "bbox": [ + 0.08, + 0.595, + 0.174, + 0.611 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.62, + 0.47, + 0.663 + ], + "angle": 0, + "content": "[1] Dana H Ballard. Modular learning in neural networks. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), volume 647, pages 279-284, 1987. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.663, + 0.472, + 0.718 + ], + "angle": 0, + "content": "[2] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. BEiT: BERT pre-training of image transformers. In Proceedings of the International Conference on Learning Representations (ICLR), 2022. 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.719, + 0.472, + 0.774 + ], + "angle": 0, + "content": "[3] Z. Cao, G. Hidalgo, T. Simon, S. Wei, and Y. Sheikh. OpenPose: Realtime multi-person 2D pose estimation using part affinity fields. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 43(01):172-186, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.776, + 0.472, + 0.845 + ], + "angle": 0, + "content": "[4] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Proceedings of the European Conference on Computer Vision (ECCV), pages 213-229, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.846, + 0.472, + 0.902 + ], + "angle": 0, + "content": "[5] Yuxin Chen, Ziqi Zhang, Chunfeng Yuan, Bing Li, Ying Deng, and Weiming Hu. Channel-wise topology refinement graph convolution for skeleton-based action recognition. In Proceedings of the IEEE/CVF International Conference on" + }, + { + "type": "list", + "bbox": [ + 0.087, + 0.62, + 0.472, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.119 + ], + "angle": 0, + "content": "Computer Vision (ICCV), pages 13359-13368, 2021. 1, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.123, + 0.894, + 0.207 + ], + "angle": 0, + "content": "[6] Yuxiao Chen, Long Zhao, Jianbo Yuan, Yu Tian, Zhaoyang Xia, Shijie Geng, Ligong Han, and Dimitris N Metaxas. Hierarchically self-supervised transformer for human skeleton representation learning. In Proceedings of the European Conference on Computer Vision (ECCV), pages 185-202, 2022. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.209, + 0.895, + 0.279 + ], + "angle": 0, + "content": "[7] Ke Cheng, Yifan Zhang, Xiangyu He, Weihan Chen, Jian Cheng, and Hanqing Lu. Skeleton-based action recognition with shift graph convolutional network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 183-192, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.281, + 0.895, + 0.322 + ], + "angle": 0, + "content": "[8] Hyung-gun Chi et al. InfoGCN: Representation learning for human skeleton-based action recognition. In CVPR, 2022. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.324, + 0.895, + 0.38 + ], + "angle": 0, + "content": "[9] Liu Chunhui, Hu Yueyu, Li Yanghao, Song Sijie, and Liu Jiaying. PKU-MMD: A large scale benchmark for continuous multi-modal human action understanding. arXiv preprint arXiv:1703.07475, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.382, + 0.892, + 0.425 + ], + "angle": 0, + "content": "[10] Kevin Clark, Minh-Thang Luong, Quoc V. Le, and Christopher D. Manning. ELECTRA: Pre-training text encoders as discriminators rather than generators. In ICLR, 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.427, + 0.892, + 0.512 + ], + "angle": 0, + "content": "[11] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. BERT: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of the Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (NAACL-HLT), pages 4171–4186, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.513, + 0.892, + 0.611 + ], + "angle": 0, + "content": "[12] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In Proceedings of the International Conference on Learning Representations (ICLR), 2021. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.612, + 0.892, + 0.669 + ], + "angle": 0, + "content": "[13] Yong Du, Yun Fu, and Liang Wang. Skeleton based action recognition with convolutional neural network. In Proceedings of the Asian Conference on Pattern Recognition (ACPR), pages 579-583, 2015. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.671, + 0.892, + 0.74 + ], + "angle": 0, + "content": "[14] Yong Du, Wei Wang, and Liang Wang. Hierarchical recurrent neural network for skeleton based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1110-1118, 2015. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.742, + 0.892, + 0.771 + ], + "angle": 0, + "content": "[15] Haodong Duan et al. Revisiting skeleton-based action recognition. In CVPR, 2022. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.772, + 0.892, + 0.83 + ], + "angle": 0, + "content": "[16] Hao-Shu Fang, Shuqin Xie, Yu-Wing Tai, and Cewu Lu. RMPE: Regional multi-person pose estimation. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 2334-2343, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.831, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[17] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 16000-16009, 2022. 2, 3, 4, 5, 8" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.895, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "10189" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.148 + ], + "angle": 0, + "content": "[18] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR), pages 770-778, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.15, + 0.472, + 0.219 + ], + "angle": 0, + "content": "[19] Qiuhong Ke, Mohammed Bennamoun, Senjian An, Ferdous Sohel, and Farid Boussaid. A new representation of skeleton sequences for 3D action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 3288-3297, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.221, + 0.471, + 0.289 + ], + "angle": 0, + "content": "[20] Boeun Kim, Hyung Jin Chang, Jungho Kim, and Jin Young Choi. Global-local motion transformer for unsupervised skeleton-based action learning. In Proceedings of the European Conference on Computer Vision (ECCV), pages 209-225, 2022. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.291, + 0.47, + 0.348 + ], + "angle": 0, + "content": "[21] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E Hinton. Imagenet classification with deep convolutional neural networks. In Proceedings of the Advances in Neural Information Processing Systems (NeurIPS), 2012. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.349, + 0.47, + 0.417 + ], + "angle": 0, + "content": "[22] Chao Li, Qiaoyong Zhong, Di Xie, and Shiliang Pu. Skeleton-based action recognition with convolutional neural networks. In Proceedings of the IEEE International Conference on Multimedia & Expo Workshops (ICMEW), pages 597-600. IEEE, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.42, + 0.47, + 0.502 + ], + "angle": 0, + "content": "[23] Linguo Li, Minsi Wang, Bingbing Ni, Hang Wang, Jiancheng Yang, and Wenjun Zhang. 3D human action representation learning via cross-view consistency pursuit. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4741-4750, 2021. 2, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.505, + 0.47, + 0.574 + ], + "angle": 0, + "content": "[24] Maosen Li, Siheng Chen, Xu Chen, Ya Zhang, Yanfeng Wang, and Qi Tian. Actional-structural graph convolutional networks for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 3595–3603, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.576, + 0.47, + 0.645 + ], + "angle": 0, + "content": "[25] Tianjiao Li, Qiuhong Ke, Hossein Rahmani, Rui En Ho, Henghui Ding, and Jun Liu. Else-Net: Elastic semantic network for continual action recognition from skeleton data. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13434–13443, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.647, + 0.47, + 0.73 + ], + "angle": 0, + "content": "[26] Duohan Liang, Guoliang Fan, Guangfeng Lin, Wanjun Chen, Xiaorong Pan, and Hong Zhu. Three-stream convolutional neural network with multi-task and ensemble learning for 3D action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW), pages 934-940, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.732, + 0.47, + 0.8 + ], + "angle": 0, + "content": "[27] Lilang Lin, Sijie Song, Wenhan Yang, and Jiaying Liu. MS2L: Multi-task self-supervised learning for skeleton based action recognition. In Proceedings of the 28th ACM International Conference on Multimedia (ACM MM), pages 2490-2498, 2020. 2, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.802, + 0.47, + 0.871 + ], + "angle": 0, + "content": "[28] Jun Liu, Amir Shahroudy, Mauricio Perez, Gang Wang, Ling-Yu Duan, and Alex C Kot. NTU RGB+D 120: A large-scale benchmark for 3D human activity understanding. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 42(10):2684-2701, 2020. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.47, + 0.902 + ], + "angle": 0, + "content": "[29] Jun Liu, Amir Shahroudy, Dong Xu, Alex C Kot, and Gang Wang. Skeleton-based action recognition using spatio" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.472, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "temporal LSTM network with trust gates. IEEE transactions on pattern analysis and machine intelligence (TPAMI), 40(12):3007-3021, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.192 + ], + "angle": 0, + "content": "[30] Jun Liu, Amir Shahroudy, Dong Xu, and Gang Wang. Spatio-temporal LSTM with trust gates for 3D human action recognition. In Proceedings of the European Conference on Computer Vision (ECCV), pages 816-833. Springer, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.194, + 0.892, + 0.248 + ], + "angle": 0, + "content": "[31] Xiao Liu, Fanjin Zhang, Zhenyu Hou, Li Mian, Zhaoyu Wang, Jing Zhang, and Jie Tang. Self-supervised learning: Generative or contrastive. IEEE Transactions on Knowledge and Data Engineering (TKDE), 35(1):857-876, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.25, + 0.892, + 0.319 + ], + "angle": 0, + "content": "[32] Ziyu Liu, Hongwen Zhang, Zhenghao Chen, Zhiyong Wang, and Wanli Ouyang. Disentangling and unifying graph convolutions for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 143-152, 2020. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.321, + 0.892, + 0.362 + ], + "angle": 0, + "content": "[33] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In Proceedings of the International Conference on Learning Representations (ICLR), 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.364, + 0.892, + 0.433 + ], + "angle": 0, + "content": "[34] Yunyao Mao, Wengang Zhou, Zhenbo Lu, Jiajun Deng, and Houqiang Li. CMD: Self-supervised 3D action representation learning with cross-modal mutual distillation. In Proceedings of the European Conference on Computer Vision (ECCV), pages 734-752, 2022. 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.435, + 0.892, + 0.489 + ], + "angle": 0, + "content": "[35] Chiara Plizzari, Marco Cannici, and Matteo Matteucci. Skeleton-based action recognition via spatial and temporal transformer networks. Computer Vision and Image Understanding, 208:103219, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.491, + 0.892, + 0.532 + ], + "angle": 0, + "content": "[36] Helei Qiu, Biao Hou, Bo Ren, and Xiaohua Zhang. Spatiotemporal tuples transformer for skeleton-based action recognition. arXiv preprint arXiv:2201.02849, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.534, + 0.892, + 0.589 + ], + "angle": 0, + "content": "[37] Haocong Rao, Shihao Xu, Xiping Hu, Jun Cheng, and Bin Hu. Augmented skeleton based contrastive action learning with momentum LSTM for unsupervised action recognition. Information Sciences, 569:90-109, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.591, + 0.892, + 0.659 + ], + "angle": 0, + "content": "[38] Amir Shahroudy, Jun Liu, Tian-Tsong Ng, and Gang Wang. NTU RGB+D: A large scale dataset for 3D human activity analysis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1010-1019, 2016. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.661, + 0.892, + 0.73 + ], + "angle": 0, + "content": "[39] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. Skeleton-based action recognition with directed graph neural networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 7912-7921, 2019. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.732, + 0.892, + 0.801 + ], + "angle": 0, + "content": "[40] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. Two-stream adaptive graph convolutional networks for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 12026-12035, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.803, + 0.892, + 0.858 + ], + "angle": 0, + "content": "[41] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. Decoupled spatial-temporal attention network for skeleton-based action-gesture recognition. In Proceedings of the Asian Conference on Computer Vision (ACCV), 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.86, + 0.894, + 0.902 + ], + "angle": 0, + "content": "[42] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. AdaSGN: Adapting joint number and model size for efficient skeleton-based action recognition. In Proceedings of" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "10190" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.111, + 0.093, + 0.469, + 0.12 + ], + "angle": 0, + "content": "the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13413-13422, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.47, + 0.189 + ], + "angle": 0, + "content": "[43] Chenyang Si, Wentao Chen, Wei Wang, Liang Wang, and Tieniu Tan. An attention enhanced graph convolutional LSTM network for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1227-1236, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.191, + 0.469, + 0.259 + ], + "angle": 0, + "content": "[44] Chenyang Si, Xuecheng Nie, Wei Wang, Liang Wang, Tieniu Tan, and Jiashi Feng. Adversarial self-supervised learning for semi-supervised 3D action recognition. In Proceedings of the European Conference on Computer Vision (ECCV), pages 35-51, 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.261, + 0.469, + 0.315 + ], + "angle": 0, + "content": "[45] Yuxin Song, Min Yang, Wenhao Wu, Dongliang He, Fu Li, and Jingdong Wang. It takes two: Masked appearance-motion modeling for self-supervised video transformer pretraining. arXiv preprint arXiv:2210.05234, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.317, + 0.469, + 0.383 + ], + "angle": 0, + "content": "[46] Kun Su, Xiulong Liu, and Eli Shlizerman. PREDICT & CLUSTER: Unsupervised skeleton based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 9631-9640, 2020. 2, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.386, + 0.469, + 0.453 + ], + "angle": 0, + "content": "[47] Yukun Su, Guosheng Lin, and Qingyao Wu. Self-supervised 3D skeleton action representation learning with motion consistency and continuity. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13328-13338, October 2021. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.456, + 0.469, + 0.522 + ], + "angle": 0, + "content": "[48] Fida Mohammad Thoker, Hazel Doughty, and Cees GM Snoek. Skeleton-contrastive 3D action representation learning. In Proceedings of the ACM International Conference on Multimedia (ACM MM), pages 1655–1663, 2021. 2, 3, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.525, + 0.469, + 0.594 + ], + "angle": 0, + "content": "[49] Guo Tianyu, Liu Hong, Chen Zhan, Liu Mengyuan, Wang Tao, and Ding Runwei. Contrastive learning from extremely augmented skeleton sequences for self-supervised action recognition. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), 2022. 2, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.595, + 0.469, + 0.677 + ], + "angle": 0, + "content": "[50] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Herve Jegou. Training data-efficient image transformers & distillation through attention. In Proceedings of the International Conference on Machine Learning (ICML), volume 139, pages 10347-10357, July 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.679, + 0.469, + 0.747 + ], + "angle": 0, + "content": "[51] Hongsong Wang and Liang Wang. Modeling temporal dynamics and spatial configurations of actions using two-stream recurrent neural networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition (CVPR), pages 499-508, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.749, + 0.469, + 0.816 + ], + "angle": 0, + "content": "[52] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 14668-14678, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.469, + 0.872 + ], + "angle": 0, + "content": "[53] Wenhan Wu, Yilei Hua, Ce zheng, Shiqian Wu, Chen Chen, and Aidong Lu. SkeletonMAE: Spatial-temporal masked autoencoders for self-supervised skeleton action recognition. arXiv preprint arXiv:2209.02399, 2022. 1, 3, 4, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.874, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[54] Jingwei Xu, Zhenbo Yu, Bingbing Ni, Jiancheng Yang, Xiaokang Yang, and Wenjun Zhang. Deep kinematics analysis" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.093, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.893, + 0.134 + ], + "angle": 0, + "content": "for monocular 3D human pose estimation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 899-908, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.136, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[55] Sijie Yan, Yuanjun Xiong, and Dahua Lin. Spatial temporal graph convolutional networks for skeleton-based action recognition. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), pages 7444-7452, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.193, + 0.892, + 0.259 + ], + "angle": 0, + "content": "[56] Di Yang, Yaohui Wang, Antitza Dantcheva, Lorenzo Garattoni, Gianpiero Francesca, and Francois Bremond. ViA: View-invariant skeleton action representation learning via motion retargeting. arXiv preprint arXiv:2209.00065, 2022.6,7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.263, + 0.892, + 0.33 + ], + "angle": 0, + "content": "[57] Haosen Yang, Deng Huang, Bin Wen, Jiannan Wu, Hongxun Yao, Yi Jiang, Xiatian Zhu, and Zehuan Yuan. Self-supervised video representation learning with motion-aware masked autoencoders. arXiv preprint arXiv:2210.04154, 2022.3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.333, + 0.892, + 0.401 + ], + "angle": 0, + "content": "[58] Siyuan Yang, Jun Liu, Shijian Lu, Meng Hwa Er, and Alex C Kot. Skeleton cloud colorization for unsupervised 3D action representation learning. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13423-13433, 2021. 2, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.404, + 0.892, + 0.471 + ], + "angle": 0, + "content": "[59] Haoyuan Zhang, Yonghong Hou, Wenjing Zhang, and Wanqing Li. Contrastive positive mining for unsupervised 3D action representation learning. In Proceedings of the European Conference on Computer Vision (ECCV), pages 36-51, 2022. 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.474, + 0.892, + 0.555 + ], + "angle": 0, + "content": "[60] Pengfei Zhang, Cuiling Lan, Wenjun Zeng, Junliang Xing, Jianru Xue, and Nanning Zheng. Semantics-guided neural networks for efficient skeleton-based human action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1112-1121, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.558, + 0.892, + 0.625 + ], + "angle": 0, + "content": "[61] Xikun Zhang, Chang Xu, and Dacheng Tao. Context aware graph convolution for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 14333–14342, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.629, + 0.892, + 0.71 + ], + "angle": 0, + "content": "[62] Nenggan Zheng, Jun Wen, Risheng Liu, Liangqu Long, Jianhua Dai, and Zhefeng Gong. Unsupervised representation learning with long-term dynamics for skeleton based action recognition. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), pages 2644-2651, 2018. 2, 3, 4, 6, 7" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.893, + 0.71 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "10191" + } + ] +] \ No newline at end of file diff --git a/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/06acdbbe-e15b-4021-a13d-3cb042fcaf0d_origin.pdf b/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/06acdbbe-e15b-4021-a13d-3cb042fcaf0d_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..cb41d431b860f01760c2c608282806abcc28633c --- /dev/null +++ b/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/06acdbbe-e15b-4021-a13d-3cb042fcaf0d_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:76761e90ab1f8d9fda8affab411409cfa341a5d755b1e15ca2d8a8db5f8bac83 +size 497108 diff --git a/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/full.md b/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/full.md new file mode 100644 index 0000000000000000000000000000000000000000..d22b5ea0b232c9cbcf786b82d133a722a1ad7c97 --- /dev/null +++ b/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/full.md @@ -0,0 +1,396 @@ +# Masked Motion Predictors are Strong 3D Action Representation Learners + +Yunyao Mao $^{1}$ Jiajun Deng $^{3}$ Wengang Zhou $^{1,2,*}$ Yao Fang $^{5}$ Wanli Ouyang $^{4}$ Houqiang Li $^{1,2,*}$ + +$^{1}$ CAS Key Laboratory of Technology in GIPAS, EEIS Department, University of Science and Technology of China $^{2}$ Institute of Artificial Intelligence, Hefei Comprehensive National Science Center + +3The University of Sydney 4Shanghai AI Laboratory 5Merchants Union Consumer Finance Company Limited + +myy2016@mail.ustc.edu.cn, jiajun.deng@sydney.edu.au, zhwg@ustc.edu.cn + +fangyao@mucfc.com, wanli.ouyang@sydney.edu.au, lihq@ustc.edu.cn + +# Abstract + +In 3D human action recognition, limited supervised data makes it challenging to fully tap into the modeling potential of powerful networks such as transformers. As a result, researchers have been actively investigating effective self-supervised pre-training strategies. In this work, we show that instead of following the prevalent pretext task to perform masked self-component reconstruction in human joints, explicit contextual motion modeling is key to the success of learning effective feature representation for 3D action recognition. Formally, we propose the Masked Motion Prediction (MAMP) framework. To be specific, the proposed MAMP takes as input the masked spatiotemporal skeleton sequence and predicts the corresponding temporal motion of the masked human joints. Considering the high temporal redundancy of the skeleton sequence, in our MAMP, the motion information also acts as an empirical semantic richness prior that guide the masking process, promoting better attention to semantically rich temporal regions. Extensive experiments on NTU-60, NTU-120, and PKU-MMD datasets show that the proposed MAMP pre-training substantially improves the performance of the adopted vanilla transformer, achieving state-of-the-art results without bells and whistles. The source code of our MAMP is available at https://github.com/maoyunyao/MAMP. + +# 1. Introduction + +How to accurately recognize human actions has been a long-standing challenge in computer vision. Recently, with the advances in techniques of depth sensing and pose estimation [3, 16, 54], skeleton-based 3D human action recognition has become an emerging problem to the community, which is of great significance in a series of applications such + +![](images/ae8114679b8c427baeed90be3a241f1c9d5bf4f842463d1125a19cf23dd20a02.jpg) +MAE + +![](images/14e74328e36d018b320e8a5b80517c1ad66d5d2451dca1d9b43ba0773cb900ec.jpg) +MAMP (Ours) + +![](images/85481d6e5ef68d8c9395b51b984810604bbd8e15fae81f4b8d1b603df762553a.jpg) +(a) Comparison of pre-training objectives. +(b) Comparison of linear probing accuracy. +Figure 1. Illustration of (a) pre-training objective comparison between masked auto encoders (MAE) and our masked motion predictors (MAMP) and (b) performance comparison between the typical MAE method, i.e., SkeletonMAE [53], and our MAMP under the linear evaluation protocol. + +as human-computer interaction, video surveillance, virtual reality, etc. Despite the computation efficiency and background robustness of skeletons, existing supervised 3D action recognition methods [5, 7, 14, 19, 24, 25, 32, 39, 42, 43, 60] heavily rely on well-annotated training sequences, which are labor-intensive and time-consuming to acquire. + +Furthermore, limited supervision also leads to the overfitting issue in general models, especially for transformers that are with weak inductive bias and high model capacity. These facts motivate the exploration of self-supervised 3D action representation learning. + +In the literature, the prevalent pretext tasks originally developed for images have been adapted for 3D action representation learning, such as colorization [58], reconstruction [62, 46, 27], contrastive learning [23, 48, 49], etc. Among them, contrastive learning once dominated 3D action representation learning with its concise framework and promising performance. Nevertheless, as a global representation learner, it still suffers from certain limitations, such as the lack of explicit constraints for temporal context modeling and the over-reliance on heuristic action data augmentations [31], impeding its further exploration of 3D actions. + +Recently, as transformers flourish in computer vision, masked autoencoder (MAE) [17] has attracted a surge of research interest for its exceptional performance. Given that a 3D skeleton serves as an abstract representation of human behaviors, there has been growing interest in applying the MAE concept to 3D action representation learning, to capture the underlying spatio-temporal dynamics of skeleton sequences. Early attempts generally followed the practice of images, employing masked self-reconstruction of human joints as the pre-training pretext. Despite considerable effort, we argue that the network is not effectively directed to prioritize contextual motion modeling in such a self-reconstruction objective, which is, however, crucial for comprehending 3D actions as the appearance information is greatly erased in human skeletons. How to better explore the contextual motion clue in self-supervised 3D action representation learning is a valid problem. + +By consolidating this idea, we introduce Masked Motion Prediction (MAMP), a simple yet effective framework to address the problem of self-supervised 3D action representation learning. Specifically, the proposed MAMP takes as input the masked spatio-temporal skeleton sequence and turns to predict the corresponding temporal motion of the masked human joints. In this way, the network is directly encouraged for contextual motion modeling. Moreover, given the observation that moments with significant motion are often critical for human action understanding, in our MAMP, the temporal motion is used not only as the pretraining objective but also as an empirical semantic richness prior that effectively guiding the skeleton masking process. Compared to the random version, the proposed motion-aware masking strategy takes additional temporal motion intensity as input. It first converts the input intensity into a probability distribution and then utilizes the reparameterization technique for efficient probability-guided masked token sampling. As a result, joints with significant motion are masked with a higher probability, facilitating + +better attention to semantically rich temporal regions. + +As illustrated in Figure 1, compared to masked self-reconstruction of human joints, masked motion prediction acts as a more effective pretext task for 3D action representation learning. It substantially alleviates the problem that the transformers cannot fully unleash their modeling potential for human actions due to the scarcity of annotated 3D skeletons. The adopted vanilla transformer sets a series of state-of-the-art records in 3D action recognition after MAMP pre-training, without the need for bells and whistles such as multi-stream ensembling. Specifically, compared to training from scratch, our MAMP demonstrates significant absolute performance improvements of $10.0\%$ and $13.2\%$ on the challenging cross-subject protocol of NTU RGB+D 60 [38] and NTU RGB+D 120 [28] datasets, resulting in top-1 accuracy of $93.1\%$ and $90.0\%$ , respectively. We hope this simple yet effective framework will serve as a strong baseline that facilitates future research on 3D action pretraining and beyond. + +Overall, we make the following three-fold contributions: + +- We present masked motion prediction to learn 3D action representation, which substantially alleviates the insufficient contextual motion modeling issue in the conventional masked self-reconstruction paradigm. +- We devise the motion-aware masking strategy, which incorporates motion intensity as an empirical semantic richness prior for adaptive joint masking. +- We conduct extensive experiments on three prevalent benchmarks to verify the effectiveness of our method. Remarkably, with our proposed MAMP, the vanilla transformer, for the first time, achieves the top-performing record for 3D action recognition. + +# 2. Related Work + +# 2.1. Supervised 3D Action Recognition + +How to better model the dynamic skeletons for supervised action recognition is an extensively studied problem. In many early works, RNNs are favored for their excellent sequential modeling capability, such as the hierarchical RNN model proposed in [14] and the 2D Spatio-Temporal LSTM in [30, 29]. In view of the great success of CNNs [21, 18] in image understanding, some methods also try to apply it to 3D action recognition. To cater for the input format, [13] and [22] treat the skeleton sequence as a three-channel (x, y, and z coordinates) pseudo-image, with the number of frames and joints as height and width, respectively. Considering the natural connections between joints, ST-GCN [55] introduces the Graph Neural Networks (GCNs) for skeleton modeling, where the convolution kernels are elaborately designed according to the skeleton topology. The astonishing performance of ST-GCN has led the trend of GCN-based 3D action recognition, with numer + +ous subsequent improvements emerging in input streams [51, 26, 40], kernel design [5, 61, 39, 32], etc. + +Recent approaches [36, 35, 41] try to introduce the popular vision transformer into 3D action recognition. However, under limited training data, vanilla transformers with weak inductive bias cannot be fully trained. Therefore, many customized designs are required in existing supervised attempts, such as temporal convolution [36], graph convolution [35, 36], space-time separation [41], etc. In our approach, we demonstrate that pre-training with masked motion prediction is key to the success of transformers in 3D action recognition. The proposed MAMP framework endows the vanilla transformer with unrivaled performance. + +# 2.2. Self-supervised 3D Action Recognition + +Self-supervised representation learning aims to capture the domain priors from unlabeled data so as to facilitate the application of the model in downstream tasks. In 3D human action recognition, many pretext tasks have been utilized to explore the action context that resides in the skeleton sequence. Among them, LongT GAN [62] and P&C [46] try to learn 3D action representation by autoencoder-based sequence reconstruction, where the decoder in P&C is further weakened to promote the learning of the feature encoder. In Colorization [58], the skeleton sequences are treated as point clouds and action representation is learned by colorizing each joint based on its spatial and temporal orders. + +Recently, many contrastive learning-based approaches [27, 48, 23, 49, 59, 34] have emerged, showing superior performance compared to earlier works. To learn better 3D action representation, they either try to dig helpful supervision across different skeleton modalities [23, 34], or explore better action data augmentation [49] and positive sample mining strategies [59]. Nevertheless, as a global feature learner originally designed for images, contrastive learning lacks explicit constraints on the exploration of temporal motion context, limiting its further development for 3D actions. + +SkeletonMAE [53] first introduces the idea of MAE[17] into transformer-based 3D action representation learning, where the original joint coordinates of masked regions are predicted. In our approach, we demonstrate that such a self-reconstruction objective is sub-optimal for learning 3D action representation. Therefore, we introduce the Masked Motion Prediction (MAMP) framework for explicit contextual motion modeling, resulting in significantly better performance compared to raw skeleton reconstruction. + +# 2.3. Masked Visual Prediction + +With the development of vision transformers [4, 12, 50], the masked prediction derived from the autoencoder [1] has revived again. Similar to the BERT [11] pre-training in NLP, the input tokens are randomly masked and corresponding objectives are predicted, which can be the raw + +pixels [17], HOG features [52], or token ids from offline learned dVAEs [2]. Recently, there have also been attempts [45, 57] to use optical flow or temporal difference of images as the auxiliary reconstruction objectives, but inferior performance is observed when they are applied alone. This is largely attributed to the high redundancy of the raw images, where the key foreground motion is difficult to be pre-extracted accurately. In our approach, we employ the idea of masked visual prediction for 3D action representation learning, with the temporal skeleton motion adopted as the only reconstruction target. Different from images, the explicit temporal correspondence of joints in the human skeleton sequence enables the ready extraction of their accurate motion context. Furthermore, we also incorporate motion intensity as the semantic richness prior to guide the masking process. + +# 3. Our Method + +# 3.1. Overview + +Figure 2 illustrates the overall pipeline of our proposed Masked Motion Prediction (MAMP) framework. It takes a skeleton sequence $S \in \mathbb{R}^{T_s \times V \times C_s}$ as input, which is randomly cropped from the original data and is resized to a fixed temporal length $T_s$ . $V$ and $C_s$ are the number of joints and coordinate channels, respectively. The motion sequence $M \in \mathbb{R}^{T_s \times V \times C_s}$ of the input is also extracted, which is defined as the differential on temporal dimension (manually padded for the first frame). + +As in most vision transformers, the input joints are linearly mapped into joint embedding $E \in \mathbb{R}^{T_e \times V \times C_e}$ . After that, the motion-aware masking strategy is applied to mask most of the embedding features under the guidance of temporal motion intensity. The remaining features are processed by the encoder-decoder architecture, where the transformer encoder learns representation from unmasked joint embedding and the transformer decoder performs contextual modeling based on the learnable mask tokens and latent representation from the transformer encoder. Different from MAE [17] that reconstructs the original signal for representation learning, in MAMP, a motion prediction head is adopted, which takes decoded features as input and predicts the temporal motion of the input skeleton sequence. + +After the aforementioned pre-training, only the joint embedding layer and the transformer encoder are reserved for downstream applications. + +# 3.2. Joint Embedding + +In most transformer-based attempts [35, 41, 36], each spatio-temporal skeleton joint is embedded separately, resulting in a large number of input tokens. Considering the temporal redundancy, in our approach, the input skeleton sequence $S \in \mathbb{R}^{T_s \times V \times C_s}$ is divided into temporally non + +![](images/143a150f455a8b964d76bd570a1c774e28c1e45e014ed5486ec7457b324ee9f3.jpg) +Figure 2. The overall pipeline of the proposed MAMP framework. Different from the self-reconstruction scheme adopted in previous works [62, 53], our MAMP learns 3D action representation by predicting the corresponding motion sequence for masked joint input. Moreover, motion information also acts as an empirical semantic richness prior that effectively guides the masking process, enabling more attention to be applied to regions with significant temporal motion intensity. + +overlapping segments $S' \in \mathbb{R}^{T_e \times V \times l \times C_s}$ , where $l$ is the length of each segment and $T_e = T_s / l$ . In each segment, joints with the same spatial position are embedded together: + +$$ +E = \operatorname {J o i n t E m b e d} \left(S ^ {\prime}\right) \in \mathbb {R} ^ {T _ {e} \times V \times C _ {e}}, \tag {1} +$$ + +where $C_e$ is the dimension of the embedding features. Compared to the original skeleton sequence, the temporal resolution of the embedding $E$ is reduced by a factor of $l$ , resulting in higher computational efficiency. + +# 3.3. Motion Extraction + +Different from RGB frames with heavy spatial redundancy, the human skeleton sequence is highly semantic, with explicit correspondence between neighboring frames. Therefore, we can easily obtain its motion $M \in \mathbb{R}^{T_s \times V \times C_s}$ by applying temporal difference on joint coordinates: + +$$ +M _ {i,:,:} = S _ {i,:,:} - S _ {i - m,:,:}, i \in m, m + 1, \dots , T _ {s} - 1, \tag {2} +$$ + +where stride $m$ controls the step size of the motion. For convenience, the motion sequence is padded to be consistent with the length of the original input: + +$$ +M _ {0: m - 1,:,:} = \left\{ \begin{array}{l l} 0, & \text {c o n s t a n t} \\ M _ {m: 2 m - 1,:,:}, & \text {r e p l i c a t e} \end{array} , \right. \tag {3} +$$ + +where constant and replicate denote constant padding (with zeros) and replicate padding for the first $m$ frames of the motion sequence, respectively. + +# 3.4. Motion-Aware Masking + +In the proposed approach, the motion information is used not only as the reconstruction target during pre-training but also as the empirical semantic richness prior that guiding the masking of embedding features. Considering that the skeleton sequence is segment-wise embedded with length $l$ , + +we extract the motion sequence $M^{\mathrm{mask}} \in \mathbb{R}^{T_i \times V \times C_i}$ with stride $m = l$ and replicate padding according to Eq. (2) and Eq. (3), which is further reshaped into $M' \in \mathbb{R}^{T_e \times V \times l \times C_i}$ as is done for $S'$ . Then, the motion intensity $I$ , which indicates the motion significance of each spatio-temporal segment, is computed as follows: + +$$ +I = \sum_ {i = 0} ^ {l} \sum_ {j = 0} ^ {C _ {i}} \left| M _ {:,:,: i, j} ^ {\prime} \right| \in \mathbb {R} ^ {T _ {e} \times V}. \tag {4} +$$ + +Since human actions are composed of a series of temporal movements, we argue that the intensity of motion largely reflects the semantic richness. Therefore in MAMP, the motion intensity is further converted into probability distribution with a temperature hyper-parameter $\tau$ : + +$$ +\pi = \operatorname {S o f t m a x} (I / \tau), \tag {5} +$$ + +which indicates the probability that each embedding feature is masked. In MAMP, the idea of gumble max is adapted for efficient probability-guided mask index sampling: + +$$ +\begin{array}{l} g = - \log (- \log \epsilon), \epsilon \in U [ 0, 1 ] ^ {T _ {\epsilon} \times V}, \\ i d x ^ {\text {m a s k}} = \text {I n d e x - o f - T o p - K} (\log \pi + g), \tag {6} \\ \end{array} +$$ + +where $U[0,1]$ denotes uniform distribution between 0 and 1. The obtained $idx^{\mathrm{mask}}$ indicates which joints are masked and is used for unmasked token selection in Section 3.5. Based on the above operations, the network is encouraged to focus more on semantically rich regions, so as to learn more discriminative 3D action representation. + +# 3.5. Masked Motion Prediction + +We follow the encoder-decoder design in MAE [17], where the transformer encoder focuses on representation learning, while the decoder is responsible for the implementation of the pre-training pretext. + +Encoder: In the encoder, separate spatio-temporal positional embedding $P_{e}^{s} \in \mathbb{R}^{1 \times V \times C_{e}}$ and $P_{e}^{t} \in \mathbb{R}^{T_{e} \times 1 \times C_{e}}$ are first element-wise added (with broadcasting) to the input joint embedding $E$ : + +$$ +E _ {p} = E + P _ {e} ^ {s} + P _ {e} ^ {t}. \tag {7} +$$ + +Then, the unmasked tokens in $E_{p}$ are selected according to the $idx^{\mathrm{mask}}$ extracted in Eq. (6) and are flattened to $E_{p}^{u} \in \mathbb{R}^{N_{u} \times C_{e}}$ , where $N_{u} = T_{e} \times V \times (1 - \mathrm{mask~ratio})$ is the number of unmasked tokens. After that, the latent representation is extracted by $L_{e}$ vanilla transformer blocks: + +$$ +H _ {0} = E _ {p} ^ {u}, +$$ + +$$ +H _ {l} ^ {\prime} = \operatorname {M S A} \left(\ln \left(H _ {l - 1}\right)\right) + H _ {l - 1}, \quad l \in 1, \dots , L _ {e} \tag {8} +$$ + +$$ +H _ {l} = \operatorname {M L P} \left(\operatorname {L N} \left(H _ {l} ^ {\prime}\right)\right) + H _ {l} ^ {\prime}, \quad l \in 1, \dots , L _ {e} +$$ + +$$ +H _ {e} ^ {u} = \mathrm {L N} \left(H _ {L _ {e}}\right), +$$ + +where MSA, MLP, and LN denote multi-head self-attention, multilayer perceptron, and layer norm, respectively. + +Decoder: In the decoder, the learnable mask tokens are inserted into $H_{e}^{u}$ according to the mask indices $idx^{\mathrm{mask}}$ . The result is reshaped back to $H_{e} \in \mathbb{R}^{T_{e} \times V \times C_{e}}$ , which is processed by $L_{d}$ decoder layers for masked modeling: + +$$ +Z _ {0} = H _ {e} + P _ {d} ^ {s} + P _ {d} ^ {t}, +$$ + +$$ +Z _ {l} ^ {\prime} = \operatorname {M S A} \left(\ln \left(Z _ {l - 1}\right)\right) + Z _ {l - 1}, \quad l \in 1, \dots , L _ {d} \tag {9} +$$ + +$$ +Z _ {l} = \operatorname {M L P} \left(\ln \left(Z _ {l} ^ {\prime}\right)\right) + Z _ {l} ^ {\prime}, \quad l \in 1, \dots , L _ {d} +$$ + +$$ +Z _ {d} = \operatorname {L N} \left(Z _ {L _ {d}}\right), +$$ + +where $P_{d}^{s}$ and $P_{d}^{t}$ are the spatial and temporal positional embedding of the transformer decoder, respectively. + +Motion Prediction: In our method, the reconstruction target is not the original skeletons, but the motion sequence $M^{\mathrm{target}}$ pre-extracted according to Eq. (2) and Eq. (3), which is normalized by its segment-wise mean and standard deviation as in [17]. Therefore, given the decoded feature $Z_{d} \in \mathbb{R}^{T_{e} \times V \times C_{d}}$ , we additionally adopt a prediction head to predict the temporal motion of masked human joints: + +$$ +M ^ {\text {p r e d}} = \text {M o t i o n P r e d H e a d} \left(Z _ {d}\right), \tag {10} +$$ + +where we empirically find that a simple fully connected layer just works well. For masked human joints, we compute the mean squared error (MSE) between the predicted result $M^{\mathrm{pred}}$ and the reconstruction target $M^{\mathrm{target}}$ : + +$$ +\mathcal {L} = \frac {1}{| i d x ^ {\text {m a s k}} |} \sum_ {(i, j) \in i d x ^ {\text {m a s k}}} \| \left(M _ {i, j,:} ^ {\text {p r e d}} - M _ {i, j,:} ^ {\text {t a r g e t}}\right) \| _ {2} ^ {2}. \tag {11} +$$ + +# 4. Experiments + +# 4.1. Datasets and Evaluation Protocols + +NTU-RGB+D 60 [38]: NTU-RGB+D 60 (NTU-60) is a large-scale dataset for human action recognition. It contains 60 action categories performed by 40 different subjects, with a total of 56,880 3D skeleton sequences. In this + +paper, we adopt the evaluation protocols recommended by the authors, namely cross-subject (X-sub) and cross-view (X-view). The former, X-sub uses the action sequences performed by half of the 40 subjects as training samples and the rest as test samples. For X-view, the training samples are action sequences captured by cameras 2 and 3, and the test samples are those captured by camera 1. + +NTU-RGB+D 120 [28]: NTU-RGB+D 120 (NTU120) is an extended version of NTU-60, in which the number of action categories is increased from 60 to 120, the number of total skeleton sequences and subjects are also increased to 114,480 and 106, respectively. Furthermore, the authors also introduce a more challenging evaluation protocol named cross-setup (X-set) to substitute for the original X-view in NTU-60. Specifically, X-set divides sequences into 32 different setups based on the camera distance and background. Samples from half of these setups are used as the training set and the remainder constitute the test set. + +PKU-MMD [9]: Following [48], to perform 3D action classification on PKU-MMD, we crop out action instances based on temporal annotations and divide them into training and test sets according to the cross-subject protocol. PKU-MMD contains two phases: PKU-MMD I (PKU-I) and PKU-MMD II (PKU-II). In PKU-I, the number of samples in training and test sets are 18,841 and 2,704, respectively. Due to the more noise introduced by the larger view variation, PKU-II is more challenging, with 5,332 samples for training and 1,613 for testing. + +# 4.2. Experimental Setup + +Network Architecture: In our MAMP framework, we adopt a vanilla vision transformer [12] as the backbone network, which consists of $L_{e} = 8$ identical building blocks. In each block, the embedding dimension is 256, the head number of the multi-head self-attention module is 8, and the hidden dimension of the feed-forward network is 1024. We employ learnable spatio-temporal separated positional embedding to the embedded inputs. The settings of the transformer decoder used during pre-training are consistent with those of the backbone encoder except that the number of layers $L_{d}$ is reduced to 5. + +Data Processing Details: Given an original skeleton sequence, a contiguous segment is first randomly cropped from it with a certain proportion $p$ ( $p$ is sampled from [0.5,1] during training and fixed to 0.9 during the test). After that, the cropped segment is resized to a fixed length $T_{s}$ by bilinear interpolation. $T_{s}$ is set to 120 by default. + +Pre-training Details: During pre-training, the masking ratio of the input token is set to $90\%$ . The target motion sequence $M^{\mathrm{target}}$ has stride $m = 1$ and is padded with zeros. We adopt the AdamW [33] optimizer with a weight decay of 0.05 and betas of (0.9, 0.95). We pre-train the network for 400 epochs with a batch size of 128. The learning rate + +
MethodInput streamNTU-60NTU-120PKU-MMD
X-subX-viewX-subX-setPhase IPhase II
3s-SkeletonCLR [23]Joint+Motion+Bone75.079.860.762.685.3-
3s-CrosSCLR [23]Joint+Motion+Bone77.883.467.966.784.921.2
3s-AimCLR [49]Joint+Motion+Bone78.983.868.268.887.439.5
LongT GAN [62]Joint only39.148.1--67.726.0
P&C [46]Joint only50.776.342.741.759.925.5
MS2L [27]Joint only52.6---64.927.6
AS-CAL [37]Joint only58.564.848.649.2--
ISC [48]Joint only76.385.267.167.980.936.0
GL-Transformer [20]Joint only76.383.866.068.7--
CPM [59]Joint only78.784.968.769.688.848.3
CMD [34]Joint only79.486.970.371.5-43.0
SkeletonMAE* [53]Joint only74.877.772.573.582.836.1
MAMP (Ours)Joint only84.989.178.679.192.253.8
+ +Table 1. Performance comparison on the NTU-60, NTU-120, and PKU-MMD datasets under the linear evaluation protocol. * indicates the re-implemented version under our framework, where improved performance is achieved. + +
MethodBackboneNTU-60
X-subX-view
CPM [59]ST-GCN84.891.1
CrossCLR [23]3s-ST-GCN86.292.5
AimCLR [49]3s-ST-GCN86.992.8
CrossCLR [23]STTFormer84.690.5
AimCLR [49]STTFormer83.990.4
SkeletonMAE [53]STTFormer86.692.9
Colorization [58]3s-DGCNN88.094.9
MCC [47]2s-AGCN89.796.3
ViA [56]2s-UINK89.696.4
Hi-TRS [6]3s-Transformer90.095.7
W/o pre-trainingTransformer83.192.6
SkeletonMAE* [53]Transformer88.594.7
MAMP (Ours)Transformer93.197.5
+ +is linearly increased to 1e-3 from 0 in the first 20 warm-up epochs and then decreased to 5e-4 by the cosine decay schedule. The experiments are conducted using the PyTorch framework on four NVIDIA RTX 3090 GPUs. + +# 4.3. Comparison with State-of-the-art Methods + +Linear Evaluation Results: In linear evaluation protocol, the pre-trained backbone is fixed and a post-attached linear classifier is trained with supervision for 100 epochs with a batch size of 256 and a learning rate of 0.1. The learning rate is decreased to 0 by the cosine decay schedule. As shown in Table 1, the performance on three datasets are reported, they are NTU-60, NTU-120, and PKU-MMD, respectively. We include latest high-performance approaches for comparison, e.g., GL-Transformer [20], CPM [59], CMD [34], 3s-CrosSLR [23], and 3s-AimCLR [49]. As + +Table 2. Performance comparison on the NTU-60 dataset under the fine-tuned evaluation protocol. + +
MethodBackboneNTU-120
X-subX-set
CPM [59]ST-GCN78.478.9
CrosCLR [23]3s-ST-GCN80.580.4
AimCLR [49]3s-ST-GCN80.180.9
CrosCLR [23]STTFormer75.077.9
AimCLR [49]STTFormer74.677.2
SkeletonMAE [53]STTFormer76.879.1
MCC [47]2s-AGCN81.383.3
ViA [56]2s-UINK85.086.5
Hi-TRS [6]3s-Transformer85.387.4
W/o pre-trainingTransformer76.879.7
SkeletonMAE* [53]Transformer87.088.9
MAMP (Ours)Transformer90.091.3
+ +Table 3. Performance comparison on the NTU-120 dataset under the fine-tuned evaluation protocol. + +
MethodNTU-60NTU-120
X-subX-viewX-subX-set
PoseC3D [15]93.796.686.089.6
CTR-CGN [5]92.496.888.990.6
InfoGCN [8]93.097.189.891.2
MAMP (Ours)93.197.590.091.3
+ +Table 4. Performance comparison with fully-supervised methods on the NTU-60 and NTU-120 datasets. Note that our MAMP does not perform multi-stream ensembling during evaluation. + +we can see, with the joint stream as the only input, our proposed MAMP outperforms these methods on all the datasets. Specifically, MAMP outperforms previous state-of-the-art method CMD by $5.5\%$ and $8.3\%$ on the challenging NTU-60 x-sub and NTU-120 x-sub, respectively. For a fair comparison, we also re-implement the Skeleton + +MAE [53] under the same settings as our approach (denote as SkeletonMAE*), where improved performance is achieved. We can find that our MAMP significantly outperforms SkeletonMAE* on all six subsets of the three datasets, demonstrating the superiority of masked motion prediction compared to the self-reconstruction of joints. + +Fine-tuned Evaluation Results: In fine-tuned evaluation protocol, an MLP head is attached to the pre-trained backbone and the whole network is fully fine-tuned for 100 epochs with a batch size of 48. The learning rate is linearly increased to 3e-4 from 0 in the first 5 warm-up epochs and then decreased to 1e-5 by the cosine decay schedule. We also adopt layer-wise lr decay [10] following [2]. As shown in Table 2 and Table 3, we evaluate the fine-tuned performance on NTU-60 and NTU-120, respectively. The vanilla transformer does not show satisfactory performance when trained directly from scratch, which is under expectation as weakly biased transformers require a large amount of training data to effectively prevent overfitting. After being pre-trained with the proposed MAMP framework, the network exhibits significant performance improvements ranging from $5\%$ to $13\%$ on the four subsets of the NTU-60 and NTU-120 datasets. The final results exceed all previous methods, even those with multi-stream ensembling such as Colorization [58], MCC [47], and ViA [56]. Moreover, our MAMP also outperforms the re-implemented Skeleton-MAE* by a considerable margin. + +We also compare our MAMP with the top-performing supervised methods like PoseC3D [15], CTR-GCN [5], and InfoGCN [8] in Table 4. Results show that without ensembling, MAMP outperforms most top-performing methods, especially on the larger NTU-120 dataset. + +Semi-supervised Evaluation Results: Following previous works [23, 34, 48], in semi-supervised evaluation protocol, the post-attached classification layer and the pre-trained encoder are fine-tuned together with only a small fraction of the training set. Apart from that, we keep other training settings consistent with the fine-tuned evaluation protocol. As in [23, 49, 59], we report the performance on the NTU-60 dataset when using $1\%$ and $10\%$ of the training set. Note that considering the randomness during training data selection, we report the average of five runs as the final results. As shown in Table 5, our proposed MAMP significantly outperforms previous works like 3s-AimCLR [49], CPM [59], CMD [34], and SkeletonMAE* [53]. When using only $1\%$ of the training data, MAMP outperforms SkeletonMAE* by $11.6\%$ and $14.0\%$ in X-sub and X-view respectively. Compared to training from scratch, MAMP pretraining brings performance improvements of more than $15.5\%$ on all subsets of NTU-60. + +Transfer Learning Evaluation Results: In transfer learning evaluation protocol, the network is pre-trained on a source dataset and then finetuned on a different target + +
MethodNTU-60
X-subX-view
(1%)(10%)(1%)(10%)
LongT GAN [62]35.262.0--
MS2L [27]33.165.1--
ASSL [44]-64.3-69.8
ISC [48]35.765.938.172.5
3s-CrosSCLR [23]51.174.450.077.8
3s-Colorization [58]48.371.752.578.9
CMD [34]50.675.453.080.2
3s-Hi-TRS [6]49.377.751.581.1
3s-AimCLR [49]54.878.254.381.6
3s-CMD [34]55.679.055.582.4
CPM [59]56.773.057.577.1
W/o pre-training38.870.840.476.0
SkeletonMAE* [53]54.480.654.683.5
MAMP (Ours)66.088.068.791.5
+ +Table 5. Performance comparison on the NTU-60 dataset under the semi-supervised evaluation protocol. We report the average of five runs as the final performance. + +
MethodTo PKU-II
NTU-60NTU-120PKU-I
LongT GAN [62]44.8-43.6
MS²L [27]45.8-44.1
ISC [48]51.152.345.1
CMD [34]56.057.0-
SkeletonMAE* [53]58.461.062.5
MAMP (Ours)70.673.270.1
+ +Table 6. Performance comparison on the PKU-II dataset under the transfer learning evaluation protocol. The source datasets are the NTU-60, NTU-120, and PKU-I datasets. + +dataset. In this way, the generalizability of the learned representation is verified. In this paper, the target dataset is PKU-MMD II and the source datasets are NTU-60, NTU-120, and PKU-MMD I, respectively. Results in Table 6 show that, compared to previous methods, the representation learned by our proposed MAMP framework exhibits the best transferability, outperforming the reproduced SkeletonMAE* [53] by $12.2\%$ , $12.2\%$ , and $7.6\%$ on the three source datasets, respectively. + +# 4.4. Ablation Study + +Superiority of Masked Motion Prediction: As shown in Table 7, to verify the superiority of masked motion prediction, we designed four different ablative experiments. Given the joint and motion streams of the original data, all possible choices of the model input and reconstruction target are traversed. We can find that our joint-to-motion prediction significantly outperforms other strategies. Under the linear evaluation protocol, our MAMP exceeds joint-to-joint pre + +![](images/f784a4107d56e905adb406dbb19a072785564cca05a75b55cc3c85450cdc67ad.jpg) +Figure 3. Pre-training loss plot. Compared to masked self-reconstruction of joints in SkeletonMAE, masked motion prediction acts as a harder pre-training objective. + +![](images/a42f403a663c5865d71429e1234acfd34e57bb9b298836e962c8a6469be7a944.jpg) +Figure 4. Ablation study on the masking ratio. The performance is evaluated on the NTU-60 X-sub dataset under the linear evaluation protocol. + +![](images/d512013717936363dde230c01cda2c4bd4602f971711e4c28c904df9f9111b46.jpg) +Figure 5. Pre-training schedule of SkeletonMAE and our MAMP. The performance is evaluated on the NTU-60 X-sub dataset under the linear evaluation protocol. + +
InputTargetNTU-60NTU-120
JointJoint74.872.5
Motion84.978.6
MotionJoint76.571.0
Motion75.970.5
+ +Table 7. Ablation study on the superiority of masked motion prediction. The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol. + +
StrategyNTU-60NTU-120
Random masking83.777.3
Motion-aware masking84.978.6
+ +dition (adopted by [53]) by $10.1\%$ and $6.1\%$ on NTU-60 and NTU-120, respectively. This suggests that predicting dynamic motion from static skeletons during pre-training facilitates better contextual modeling of 3D human actions. + +We also visualize the pre-training loss in Figure 3. Unlike the fast convergence of SkeletonMAE, masked motion prediction serves as a much harder pre-training objective. + +Mask Sampling Strategy: In our approach, we employ the vanilla transformer as the backbone network, where embedding features at any spatio-temporal location can be freely masked as in MAE [17]. To verify the effectiveness of the proposed motion-aware masking strategy, we compare its performance with that of random masking in Table 8. As we can see, our motion-aware masking strategy brings absolute performance improvements of $1.2\%$ and $1.3\%$ on NTU-60 and NTU-120, respectively. This suggests that the motion information, as an empirical semantic richness prior, can effectively guide the skeleton masking process. + +Segment Length: We evaluated the performance of the learned representation under different segment lengths $l$ used in the joint embedding process. For a fair comparison, we resize the original input sequence to ensure that the + +Table 8. Ablation study on the mask sampling strategy. The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol. + +
Te=Ts/lTslNTU-60NTU-120
3060284.677.8
120484.978.6
180683.378.6
240884.577.9
+ +Table 9. Ablation study on the segment length $l$ used in the joint embedding process. For a fair comparison, the input length $T_{s}$ is adjusted to ensure that the embedded features have a fixed length $T_{e}$ . The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol. + +
LdNTU-60NTU-120
283.377.2
384.977.6
484.677.5
584.978.6
+ +(a) Decoder depth. + +
CdNTU-60NTU-120
6482.374.2
12883.577.3
25684.978.6
51284.577.1
+ +(b) Decoder width. + +Table 10. Ablation study on the decoder design. The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol. + +embedded features have a fixed length $T_{e} = T_{s} / l = 30$ . As shown in Table 9, a segment length of 4 brings the best performance on both NTU-60 and NTU-120 datasets. + +Decoder Design: We experimented with different numbers of layers and widths (feature dimensions) for the transformer decoder. As shown in Table 10 (a), our MAMP exhibits the best performance on the NTU-60 and NTU-120 datasets when the number of decoder layers is 3 and 5, respectively. The experimental results of the decoder width are in Table 10 (b), where a width of 256 brings the best performance. Overall, a decoder with 5 layers and a width of 256 is adopted in our MAMP framework by default. + +Masking Ratio: As shown in Figure 4, we experimented with different masking ratios. Results on NTU-60 X-sub show that either too large or too small masking ratios have a negative impact on performance. We empirically found that a masking ratio of $90\%$ exhibits the best results. + +Pre-training Schedule: We studied the influence of the pre-training schedule length. As shown in Figure 5, both SkeletonMAE and our MAMP exhibit higher performance with longer pre-training schedules. It is worth mentioning that our MAMP significantly outperforms SkeletonMAE for all pre-training schedules with lengths ranging from 80 to 400 epochs, demonstrating the stability and superiority of the proposed masked motion prediction strategy. + +# 5. Conclusion + +In this work, we present MAMP, a simple yet effective framework for 3D action representation learning. We show that compared to conventional masked self-reconstruction of human joints, masked joint-to-motion prediction is demonstrated to be more effective for contextual motion modeling of 3D human actions. Given the high temporal redundancy of the skeleton sequence, we further devise the motion-aware masking strategy, which incorporates motion intensity as the empirical semantic richness prior for adaptive skeleton masking, facilitating better attention to semantically rich temporal regions. We conduct extensive experiments on three prevalent benchmarks under four evaluation protocols. Results show that the proposed MAMP brings remarkable performance improvements and sets a series of new state-of-the-art records, unleashing the tremendous potential of vanilla transformers for 3D action modeling. + +Acknowledgement: This work was supported by NSFC under Contract U20A20183 & 61836011. It was also supported by the GPU cluster built by MCC Lab of Information Science and Technology Institution, USTC, and the Supercomputing Center of the USTC. + +# References + +[1] Dana H Ballard. Modular learning in neural networks. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), volume 647, pages 279-284, 1987. 3 +[2] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. BEiT: BERT pre-training of image transformers. In Proceedings of the International Conference on Learning Representations (ICLR), 2022. 3, 7 +[3] Z. Cao, G. Hidalgo, T. Simon, S. Wei, and Y. Sheikh. OpenPose: Realtime multi-person 2D pose estimation using part affinity fields. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 43(01):172-186, 2021. 1 +[4] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Proceedings of the European Conference on Computer Vision (ECCV), pages 213-229, 2020. 3 +[5] Yuxin Chen, Ziqi Zhang, Chunfeng Yuan, Bing Li, Ying Deng, and Weiming Hu. Channel-wise topology refinement graph convolution for skeleton-based action recognition. In Proceedings of the IEEE/CVF International Conference on + +Computer Vision (ICCV), pages 13359-13368, 2021. 1, 3, 6, 7 +[6] Yuxiao Chen, Long Zhao, Jianbo Yuan, Yu Tian, Zhaoyang Xia, Shijie Geng, Ligong Han, and Dimitris N Metaxas. Hierarchically self-supervised transformer for human skeleton representation learning. In Proceedings of the European Conference on Computer Vision (ECCV), pages 185-202, 2022. 6, 7 +[7] Ke Cheng, Yifan Zhang, Xiangyu He, Weihan Chen, Jian Cheng, and Hanqing Lu. Skeleton-based action recognition with shift graph convolutional network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 183-192, 2020. 1 +[8] Hyung-gun Chi et al. InfoGCN: Representation learning for human skeleton-based action recognition. In CVPR, 2022. 6, 7 +[9] Liu Chunhui, Hu Yueyu, Li Yanghao, Song Sijie, and Liu Jiaying. PKU-MMD: A large scale benchmark for continuous multi-modal human action understanding. arXiv preprint arXiv:1703.07475, 2017. 5 +[10] Kevin Clark, Minh-Thang Luong, Quoc V. Le, and Christopher D. Manning. ELECTRA: Pre-training text encoders as discriminators rather than generators. In ICLR, 2020. 7 +[11] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. BERT: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of the Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (NAACL-HLT), pages 4171–4186, 2019. 3 +[12] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In Proceedings of the International Conference on Learning Representations (ICLR), 2021. 3, 5 +[13] Yong Du, Yun Fu, and Liang Wang. Skeleton based action recognition with convolutional neural network. In Proceedings of the Asian Conference on Pattern Recognition (ACPR), pages 579-583, 2015. 2 +[14] Yong Du, Wei Wang, and Liang Wang. Hierarchical recurrent neural network for skeleton based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1110-1118, 2015. 1, 2 +[15] Haodong Duan et al. Revisiting skeleton-based action recognition. In CVPR, 2022. 6, 7 +[16] Hao-Shu Fang, Shuqin Xie, Yu-Wing Tai, and Cewu Lu. RMPE: Regional multi-person pose estimation. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 2334-2343, 2017. 1 +[17] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 16000-16009, 2022. 2, 3, 4, 5, 8 + +[18] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR), pages 770-778, 2016. 2 +[19] Qiuhong Ke, Mohammed Bennamoun, Senjian An, Ferdous Sohel, and Farid Boussaid. A new representation of skeleton sequences for 3D action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 3288-3297, 2017. 1 +[20] Boeun Kim, Hyung Jin Chang, Jungho Kim, and Jin Young Choi. Global-local motion transformer for unsupervised skeleton-based action learning. In Proceedings of the European Conference on Computer Vision (ECCV), pages 209-225, 2022. 6 +[21] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E Hinton. Imagenet classification with deep convolutional neural networks. In Proceedings of the Advances in Neural Information Processing Systems (NeurIPS), 2012. 2 +[22] Chao Li, Qiaoyong Zhong, Di Xie, and Shiliang Pu. Skeleton-based action recognition with convolutional neural networks. In Proceedings of the IEEE International Conference on Multimedia & Expo Workshops (ICMEW), pages 597-600. IEEE, 2017. 2 +[23] Linguo Li, Minsi Wang, Bingbing Ni, Hang Wang, Jiancheng Yang, and Wenjun Zhang. 3D human action representation learning via cross-view consistency pursuit. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4741-4750, 2021. 2, 3, 6, 7 +[24] Maosen Li, Siheng Chen, Xu Chen, Ya Zhang, Yanfeng Wang, and Qi Tian. Actional-structural graph convolutional networks for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 3595–3603, 2019. 1 +[25] Tianjiao Li, Qiuhong Ke, Hossein Rahmani, Rui En Ho, Henghui Ding, and Jun Liu. Else-Net: Elastic semantic network for continual action recognition from skeleton data. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13434–13443, 2021. 1 +[26] Duohan Liang, Guoliang Fan, Guangfeng Lin, Wanjun Chen, Xiaorong Pan, and Hong Zhu. Three-stream convolutional neural network with multi-task and ensemble learning for 3D action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW), pages 934-940, 2019. 3 +[27] Lilang Lin, Sijie Song, Wenhan Yang, and Jiaying Liu. MS2L: Multi-task self-supervised learning for skeleton based action recognition. In Proceedings of the 28th ACM International Conference on Multimedia (ACM MM), pages 2490-2498, 2020. 2, 3, 6, 7 +[28] Jun Liu, Amir Shahroudy, Mauricio Perez, Gang Wang, Ling-Yu Duan, and Alex C Kot. NTU RGB+D 120: A large-scale benchmark for 3D human activity understanding. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 42(10):2684-2701, 2020. 2, 5 +[29] Jun Liu, Amir Shahroudy, Dong Xu, Alex C Kot, and Gang Wang. Skeleton-based action recognition using spatio + +temporal LSTM network with trust gates. IEEE transactions on pattern analysis and machine intelligence (TPAMI), 40(12):3007-3021, 2017. 2 +[30] Jun Liu, Amir Shahroudy, Dong Xu, and Gang Wang. Spatio-temporal LSTM with trust gates for 3D human action recognition. In Proceedings of the European Conference on Computer Vision (ECCV), pages 816-833. Springer, 2016. 2 +[31] Xiao Liu, Fanjin Zhang, Zhenyu Hou, Li Mian, Zhaoyu Wang, Jing Zhang, and Jie Tang. Self-supervised learning: Generative or contrastive. IEEE Transactions on Knowledge and Data Engineering (TKDE), 35(1):857-876, 2023. 2 +[32] Ziyu Liu, Hongwen Zhang, Zhenghao Chen, Zhiyong Wang, and Wanli Ouyang. Disentangling and unifying graph convolutions for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 143-152, 2020. 1, 3 +[33] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In Proceedings of the International Conference on Learning Representations (ICLR), 2019. 5 +[34] Yunyao Mao, Wengang Zhou, Zhenbo Lu, Jiajun Deng, and Houqiang Li. CMD: Self-supervised 3D action representation learning with cross-modal mutual distillation. In Proceedings of the European Conference on Computer Vision (ECCV), pages 734-752, 2022. 3, 6, 7 +[35] Chiara Plizzari, Marco Cannici, and Matteo Matteucci. Skeleton-based action recognition via spatial and temporal transformer networks. Computer Vision and Image Understanding, 208:103219, 2021. 3 +[36] Helei Qiu, Biao Hou, Bo Ren, and Xiaohua Zhang. Spatiotemporal tuples transformer for skeleton-based action recognition. arXiv preprint arXiv:2201.02849, 2022. 3 +[37] Haocong Rao, Shihao Xu, Xiping Hu, Jun Cheng, and Bin Hu. Augmented skeleton based contrastive action learning with momentum LSTM for unsupervised action recognition. Information Sciences, 569:90-109, 2021. 6 +[38] Amir Shahroudy, Jun Liu, Tian-Tsong Ng, and Gang Wang. NTU RGB+D: A large scale dataset for 3D human activity analysis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1010-1019, 2016. 2, 5 +[39] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. Skeleton-based action recognition with directed graph neural networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 7912-7921, 2019. 1, 3 +[40] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. Two-stream adaptive graph convolutional networks for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 12026-12035, 2019. 3 +[41] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. Decoupled spatial-temporal attention network for skeleton-based action-gesture recognition. In Proceedings of the Asian Conference on Computer Vision (ACCV), 2020. 3 +[42] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. AdaSGN: Adapting joint number and model size for efficient skeleton-based action recognition. In Proceedings of + +the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13413-13422, 2021. 1 +[43] Chenyang Si, Wentao Chen, Wei Wang, Liang Wang, and Tieniu Tan. An attention enhanced graph convolutional LSTM network for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1227-1236, 2019. 1 +[44] Chenyang Si, Xuecheng Nie, Wei Wang, Liang Wang, Tieniu Tan, and Jiashi Feng. Adversarial self-supervised learning for semi-supervised 3D action recognition. In Proceedings of the European Conference on Computer Vision (ECCV), pages 35-51, 2020. 7 +[45] Yuxin Song, Min Yang, Wenhao Wu, Dongliang He, Fu Li, and Jingdong Wang. It takes two: Masked appearance-motion modeling for self-supervised video transformer pretraining. arXiv preprint arXiv:2210.05234, 2022. 3 +[46] Kun Su, Xiulong Liu, and Eli Shlizerman. PREDICT & CLUSTER: Unsupervised skeleton based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 9631-9640, 2020. 2, 3, 6 +[47] Yukun Su, Guosheng Lin, and Qingyao Wu. Self-supervised 3D skeleton action representation learning with motion consistency and continuity. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13328-13338, October 2021. 6, 7 +[48] Fida Mohammad Thoker, Hazel Doughty, and Cees GM Snoek. Skeleton-contrastive 3D action representation learning. In Proceedings of the ACM International Conference on Multimedia (ACM MM), pages 1655–1663, 2021. 2, 3, 5, 6, 7 +[49] Guo Tianyu, Liu Hong, Chen Zhan, Liu Mengyuan, Wang Tao, and Ding Runwei. Contrastive learning from extremely augmented skeleton sequences for self-supervised action recognition. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), 2022. 2, 3, 6, 7 +[50] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Herve Jegou. Training data-efficient image transformers & distillation through attention. In Proceedings of the International Conference on Machine Learning (ICML), volume 139, pages 10347-10357, July 2021. 3 +[51] Hongsong Wang and Liang Wang. Modeling temporal dynamics and spatial configurations of actions using two-stream recurrent neural networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition (CVPR), pages 499-508, 2017. 3 +[52] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 14668-14678, 2022. 3 +[53] Wenhan Wu, Yilei Hua, Ce zheng, Shiqian Wu, Chen Chen, and Aidong Lu. SkeletonMAE: Spatial-temporal masked autoencoders for self-supervised skeleton action recognition. arXiv preprint arXiv:2209.02399, 2022. 1, 3, 4, 6, 7, 8 +[54] Jingwei Xu, Zhenbo Yu, Bingbing Ni, Jiancheng Yang, Xiaokang Yang, and Wenjun Zhang. Deep kinematics analysis + +for monocular 3D human pose estimation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 899-908, 2020. 1 +[55] Sijie Yan, Yuanjun Xiong, and Dahua Lin. Spatial temporal graph convolutional networks for skeleton-based action recognition. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), pages 7444-7452, 2018. 2 +[56] Di Yang, Yaohui Wang, Antitza Dantcheva, Lorenzo Garattoni, Gianpiero Francesca, and Francois Bremond. ViA: View-invariant skeleton action representation learning via motion retargeting. arXiv preprint arXiv:2209.00065, 2022.6,7 +[57] Haosen Yang, Deng Huang, Bin Wen, Jiannan Wu, Hongxun Yao, Yi Jiang, Xiatian Zhu, and Zehuan Yuan. Self-supervised video representation learning with motion-aware masked autoencoders. arXiv preprint arXiv:2210.04154, 2022.3 +[58] Siyuan Yang, Jun Liu, Shijian Lu, Meng Hwa Er, and Alex C Kot. Skeleton cloud colorization for unsupervised 3D action representation learning. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13423-13433, 2021. 2, 3, 6, 7 +[59] Haoyuan Zhang, Yonghong Hou, Wenjing Zhang, and Wanqing Li. Contrastive positive mining for unsupervised 3D action representation learning. In Proceedings of the European Conference on Computer Vision (ECCV), pages 36-51, 2022. 3, 6, 7 +[60] Pengfei Zhang, Cuiling Lan, Wenjun Zeng, Junliang Xing, Jianru Xue, and Nanning Zheng. Semantics-guided neural networks for efficient skeleton-based human action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1112-1121, 2020. 1 +[61] Xikun Zhang, Chang Xu, and Dacheng Tao. Context aware graph convolution for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 14333–14342, 2020. 3 +[62] Nenggan Zheng, Jun Wen, Risheng Liu, Liangqu Long, Jianhua Dai, and Zhefeng Gong. Unsupervised representation learning with long-term dynamics for skeleton based action recognition. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), pages 2644-2651, 2018. 2, 3, 4, 6, 7 \ No newline at end of file diff --git a/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/images.zip b/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..3c268a584d7216b40d94632f9423bcfbbaf2da0d --- /dev/null +++ b/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:e1dc0ee90d117504f26642d87afe56a8a34321b1132cc9b5e9b6cf4958549231 +size 630203 diff --git a/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/layout.json b/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..fc0b39fd239c3853c8c3f04847c9fa65bbd62d62 --- /dev/null +++ b/2023/Masked Motion Predictors are Strong 3D Action Representation Learners/layout.json @@ -0,0 +1,9812 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 68, + 103, + 525, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 103, + 525, + 121 + ], + "spans": [ + { + "bbox": [ + 68, + 103, + 525, + 121 + ], + "type": "text", + "content": "Masked Motion Predictors are Strong 3D Action Representation Learners" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "spans": [ + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "text", + "content": "Yunyao Mao" + }, + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "text", + "content": " Jiajun Deng" + }, + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "text", + "content": " Wengang Zhou" + }, + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "inline_equation", + "content": "^{1,2,*}" + }, + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "text", + "content": " Yao Fang" + }, + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "inline_equation", + "content": "^{5}" + }, + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "text", + "content": " Wanli Ouyang" + }, + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "text", + "content": " Houqiang Li" + }, + { + "bbox": [ + 56, + 141, + 536, + 159 + ], + "type": "inline_equation", + "content": "^{1,2,*}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 66, + 159, + 529, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 159, + 529, + 185 + ], + "spans": [ + { + "bbox": [ + 66, + 159, + 529, + 185 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 66, + 159, + 529, + 185 + ], + "type": "text", + "content": "CAS Key Laboratory of Technology in GIPAS, EEIS Department, University of Science and Technology of China " + }, + { + "bbox": [ + 66, + 159, + 529, + 185 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 66, + 159, + 529, + 185 + ], + "type": "text", + "content": "Institute of Artificial Intelligence, Hefei Comprehensive National Science Center" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 65, + 186, + 529, + 200 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 186, + 529, + 200 + ], + "spans": [ + { + "bbox": [ + 65, + 186, + 529, + 200 + ], + "type": "text", + "content": "3The University of Sydney 4Shanghai AI Laboratory 5Merchants Union Consumer Finance Company Limited" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 108, + 201, + 484, + 213 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 108, + 201, + 484, + 213 + ], + "spans": [ + { + "bbox": [ + 108, + 201, + 484, + 213 + ], + "type": "text", + "content": "myy2016@mail.ustc.edu.cn, jiajun.deng@sydney.edu.au, zhwg@ustc.edu.cn" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 126, + 216, + 468, + 227 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 126, + 216, + 468, + 227 + ], + "spans": [ + { + "bbox": [ + 126, + 216, + 468, + 227 + ], + "type": "text", + "content": "fangyao@mucfc.com, wanli.ouyang@sydney.edu.au, lihq@ustc.edu.cn" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 143, + 255, + 192, + 268 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 255, + 192, + 268 + ], + "spans": [ + { + "bbox": [ + 143, + 255, + 192, + 268 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 280, + 290, + 579 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 280, + 290, + 579 + ], + "spans": [ + { + "bbox": [ + 46, + 280, + 290, + 579 + ], + "type": "text", + "content": "In 3D human action recognition, limited supervised data makes it challenging to fully tap into the modeling potential of powerful networks such as transformers. As a result, researchers have been actively investigating effective self-supervised pre-training strategies. In this work, we show that instead of following the prevalent pretext task to perform masked self-component reconstruction in human joints, explicit contextual motion modeling is key to the success of learning effective feature representation for 3D action recognition. Formally, we propose the Masked Motion Prediction (MAMP) framework. To be specific, the proposed MAMP takes as input the masked spatiotemporal skeleton sequence and predicts the corresponding temporal motion of the masked human joints. Considering the high temporal redundancy of the skeleton sequence, in our MAMP, the motion information also acts as an empirical semantic richness prior that guide the masking process, promoting better attention to semantically rich temporal regions. Extensive experiments on NTU-60, NTU-120, and PKU-MMD datasets show that the proposed MAMP pre-training substantially improves the performance of the adopted vanilla transformer, achieving state-of-the-art results without bells and whistles. The source code of our MAMP is available at https://github.com/maoyunyao/MAMP." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 602, + 128, + 615 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 602, + 128, + 615 + ], + "spans": [ + { + "bbox": [ + 47, + 602, + 128, + 615 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 623, + 287, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 623, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 623, + 287, + 696 + ], + "type": "text", + "content": "How to accurately recognize human actions has been a long-standing challenge in computer vision. Recently, with the advances in techniques of depth sensing and pose estimation [3, 16, 54], skeleton-based 3D human action recognition has become an emerging problem to the community, which is of great significance in a series of applications such" + } + ] + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 319, + 252, + 423, + 390 + ], + "blocks": [ + { + "bbox": [ + 319, + 252, + 423, + 390 + ], + "lines": [ + { + "bbox": [ + 319, + 252, + 423, + 390 + ], + "spans": [ + { + "bbox": [ + 319, + 252, + 423, + 390 + ], + "type": "image", + "image_path": "ae8114679b8c427baeed90be3a241f1c9d5bf4f842463d1125a19cf23dd20a02.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 353, + 394, + 373, + 403 + ], + "lines": [ + { + "bbox": [ + 353, + 394, + 373, + 403 + ], + "spans": [ + { + "bbox": [ + 353, + 394, + 373, + 403 + ], + "type": "text", + "content": "MAE" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 430, + 252, + 534, + 389 + ], + "blocks": [ + { + "bbox": [ + 430, + 252, + 534, + 389 + ], + "lines": [ + { + "bbox": [ + 430, + 252, + 534, + 389 + ], + "spans": [ + { + "bbox": [ + 430, + 252, + 534, + 389 + ], + "type": "image", + "image_path": "14e74328e36d018b320e8a5b80517c1ad66d5d2451dca1d9b43ba0773cb900ec.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 450, + 394, + 499, + 403 + ], + "lines": [ + { + "bbox": [ + 450, + 394, + 499, + 403 + ], + "spans": [ + { + "bbox": [ + 450, + 394, + 499, + 403 + ], + "type": "text", + "content": "MAMP (Ours)" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 316, + 425, + 533, + 543 + ], + "blocks": [ + { + "bbox": [ + 349, + 408, + 503, + 421 + ], + "lines": [ + { + "bbox": [ + 349, + 408, + 503, + 421 + ], + "spans": [ + { + "bbox": [ + 349, + 408, + 503, + 421 + ], + "type": "text", + "content": "(a) Comparison of pre-training objectives." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 316, + 425, + 533, + 543 + ], + "lines": [ + { + "bbox": [ + 316, + 425, + 533, + 543 + ], + "spans": [ + { + "bbox": [ + 316, + 425, + 533, + 543 + ], + "type": "image", + "image_path": "85481d6e5ef68d8c9395b51b984810604bbd8e15fae81f4b8d1b603df762553a.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 346, + 548, + 503, + 559 + ], + "lines": [ + { + "bbox": [ + 346, + 548, + 503, + 559 + ], + "spans": [ + { + "bbox": [ + 346, + 548, + 503, + 559 + ], + "type": "text", + "content": "(b) Comparison of linear probing accuracy." + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 304, + 563, + 547, + 619 + ], + "lines": [ + { + "bbox": [ + 304, + 563, + 547, + 619 + ], + "spans": [ + { + "bbox": [ + 304, + 563, + 547, + 619 + ], + "type": "text", + "content": "Figure 1. Illustration of (a) pre-training objective comparison between masked auto encoders (MAE) and our masked motion predictors (MAMP) and (b) performance comparison between the typical MAE method, i.e., SkeletonMAE [53], and our MAMP under the linear evaluation protocol." + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 641, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 547, + 715 + ], + "type": "text", + "content": "as human-computer interaction, video surveillance, virtual reality, etc. Despite the computation efficiency and background robustness of skeletons, existing supervised 3D action recognition methods [5, 7, 14, 19, 24, 25, 32, 39, 42, 43, 60] heavily rely on well-annotated training sequences, which are labor-intensive and time-consuming to acquire." + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 702, + 247, + 714 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 247, + 714 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 247, + 714 + ], + "type": "text", + "content": "*Corresponding authors: Wengang Zhou and Houqiang Li" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10181" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 133 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 133 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 133 + ], + "type": "text", + "content": "Furthermore, limited supervision also leads to the overfitting issue in general models, especially for transformers that are with weak inductive bias and high model capacity. These facts motivate the exploration of self-supervised 3D action representation learning." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 134, + 286, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 134, + 286, + 266 + ], + "spans": [ + { + "bbox": [ + 47, + 134, + 286, + 266 + ], + "type": "text", + "content": "In the literature, the prevalent pretext tasks originally developed for images have been adapted for 3D action representation learning, such as colorization [58], reconstruction [62, 46, 27], contrastive learning [23, 48, 49], etc. Among them, contrastive learning once dominated 3D action representation learning with its concise framework and promising performance. Nevertheless, as a global representation learner, it still suffers from certain limitations, such as the lack of explicit constraints for temporal context modeling and the over-reliance on heuristic action data augmentations [31], impeding its further exploration of 3D actions." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 269, + 286, + 472 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 269, + 286, + 472 + ], + "spans": [ + { + "bbox": [ + 47, + 269, + 286, + 472 + ], + "type": "text", + "content": "Recently, as transformers flourish in computer vision, masked autoencoder (MAE) [17] has attracted a surge of research interest for its exceptional performance. Given that a 3D skeleton serves as an abstract representation of human behaviors, there has been growing interest in applying the MAE concept to 3D action representation learning, to capture the underlying spatio-temporal dynamics of skeleton sequences. Early attempts generally followed the practice of images, employing masked self-reconstruction of human joints as the pre-training pretext. Despite considerable effort, we argue that the network is not effectively directed to prioritize contextual motion modeling in such a self-reconstruction objective, which is, however, crucial for comprehending 3D actions as the appearance information is greatly erased in human skeletons. How to better explore the contextual motion clue in self-supervised 3D action representation learning is a valid problem." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 474, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 474, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 474, + 286, + 713 + ], + "type": "text", + "content": "By consolidating this idea, we introduce Masked Motion Prediction (MAMP), a simple yet effective framework to address the problem of self-supervised 3D action representation learning. Specifically, the proposed MAMP takes as input the masked spatio-temporal skeleton sequence and turns to predict the corresponding temporal motion of the masked human joints. In this way, the network is directly encouraged for contextual motion modeling. Moreover, given the observation that moments with significant motion are often critical for human action understanding, in our MAMP, the temporal motion is used not only as the pretraining objective but also as an empirical semantic richness prior that effectively guiding the skeleton masking process. Compared to the random version, the proposed motion-aware masking strategy takes additional temporal motion intensity as input. It first converts the input intensity into a probability distribution and then utilizes the reparameterization technique for efficient probability-guided masked token sampling. As a result, joints with significant motion are masked with a higher probability, facilitating" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 305, + 72, + 522, + 84 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 522, + 84 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 522, + 84 + ], + "type": "text", + "content": "better attention to semantically rich temporal regions." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 85, + 545, + 300 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 85, + 545, + 300 + ], + "spans": [ + { + "bbox": [ + 304, + 85, + 545, + 300 + ], + "type": "text", + "content": "As illustrated in Figure 1, compared to masked self-reconstruction of human joints, masked motion prediction acts as a more effective pretext task for 3D action representation learning. It substantially alleviates the problem that the transformers cannot fully unleash their modeling potential for human actions due to the scarcity of annotated 3D skeletons. The adopted vanilla transformer sets a series of state-of-the-art records in 3D action recognition after MAMP pre-training, without the need for bells and whistles such as multi-stream ensembling. Specifically, compared to training from scratch, our MAMP demonstrates significant absolute performance improvements of " + }, + { + "bbox": [ + 304, + 85, + 545, + 300 + ], + "type": "inline_equation", + "content": "10.0\\%" + }, + { + "bbox": [ + 304, + 85, + 545, + 300 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 85, + 545, + 300 + ], + "type": "inline_equation", + "content": "13.2\\%" + }, + { + "bbox": [ + 304, + 85, + 545, + 300 + ], + "type": "text", + "content": " on the challenging cross-subject protocol of NTU RGB+D 60 [38] and NTU RGB+D 120 [28] datasets, resulting in top-1 accuracy of " + }, + { + "bbox": [ + 304, + 85, + 545, + 300 + ], + "type": "inline_equation", + "content": "93.1\\%" + }, + { + "bbox": [ + 304, + 85, + 545, + 300 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 85, + 545, + 300 + ], + "type": "inline_equation", + "content": "90.0\\%" + }, + { + "bbox": [ + 304, + 85, + 545, + 300 + ], + "type": "text", + "content": ", respectively. We hope this simple yet effective framework will serve as a strong baseline that facilitates future research on 3D action pretraining and beyond." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 317, + 301, + 544, + 312 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 301, + 544, + 312 + ], + "spans": [ + { + "bbox": [ + 317, + 301, + 544, + 312 + ], + "type": "text", + "content": "Overall, we make the following three-fold contributions:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 314, + 544, + 456 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 317, + 314, + 544, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 314, + 544, + 361 + ], + "spans": [ + { + "bbox": [ + 317, + 314, + 544, + 361 + ], + "type": "text", + "content": "- We present masked motion prediction to learn 3D action representation, which substantially alleviates the insufficient contextual motion modeling issue in the conventional masked self-reconstruction paradigm." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 361, + 544, + 396 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 361, + 544, + 396 + ], + "spans": [ + { + "bbox": [ + 317, + 361, + 544, + 396 + ], + "type": "text", + "content": "- We devise the motion-aware masking strategy, which incorporates motion intensity as an empirical semantic richness prior for adaptive joint masking." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 317, + 398, + 544, + 456 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 398, + 544, + 456 + ], + "spans": [ + { + "bbox": [ + 317, + 398, + 544, + 456 + ], + "type": "text", + "content": "- We conduct extensive experiments on three prevalent benchmarks to verify the effectiveness of our method. Remarkably, with our proposed MAMP, the vanilla transformer, for the first time, achieves the top-performing record for 3D action recognition." + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 470, + 391, + 482 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 470, + 391, + 482 + ], + "spans": [ + { + "bbox": [ + 306, + 470, + 391, + 482 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 491, + 488, + 503 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 491, + 488, + 503 + ], + "spans": [ + { + "bbox": [ + 306, + 491, + 488, + 503 + ], + "type": "text", + "content": "2.1. Supervised 3D Action Recognition" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 510, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 510, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 545, + 713 + ], + "type": "text", + "content": "How to better model the dynamic skeletons for supervised action recognition is an extensively studied problem. In many early works, RNNs are favored for their excellent sequential modeling capability, such as the hierarchical RNN model proposed in [14] and the 2D Spatio-Temporal LSTM in [30, 29]. In view of the great success of CNNs [21, 18] in image understanding, some methods also try to apply it to 3D action recognition. To cater for the input format, [13] and [22] treat the skeleton sequence as a three-channel (x, y, and z coordinates) pseudo-image, with the number of frames and joints as height and width, respectively. Considering the natural connections between joints, ST-GCN [55] introduces the Graph Neural Networks (GCNs) for skeleton modeling, where the convolution kernels are elaborately designed according to the skeleton topology. The astonishing performance of ST-GCN has led the trend of GCN-based 3D action recognition, with numer" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10182" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "type": "text", + "content": "ous subsequent improvements emerging in input streams [51, 26, 40], kernel design [5, 61, 39, 32], etc." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 96, + 288, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 96, + 288, + 228 + ], + "spans": [ + { + "bbox": [ + 46, + 96, + 288, + 228 + ], + "type": "text", + "content": "Recent approaches [36, 35, 41] try to introduce the popular vision transformer into 3D action recognition. However, under limited training data, vanilla transformers with weak inductive bias cannot be fully trained. Therefore, many customized designs are required in existing supervised attempts, such as temporal convolution [36], graph convolution [35, 36], space-time separation [41], etc. In our approach, we demonstrate that pre-training with masked motion prediction is key to the success of transformers in 3D action recognition. The proposed MAMP framework endows the vanilla transformer with unrivaled performance." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 236, + 250, + 249 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 236, + 250, + 249 + ], + "spans": [ + { + "bbox": [ + 47, + 236, + 250, + 249 + ], + "type": "text", + "content": "2.2. Self-supervised 3D Action Recognition" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 255, + 287, + 397 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 255, + 287, + 397 + ], + "spans": [ + { + "bbox": [ + 46, + 255, + 287, + 397 + ], + "type": "text", + "content": "Self-supervised representation learning aims to capture the domain priors from unlabeled data so as to facilitate the application of the model in downstream tasks. In 3D human action recognition, many pretext tasks have been utilized to explore the action context that resides in the skeleton sequence. Among them, LongT GAN [62] and P&C [46] try to learn 3D action representation by autoencoder-based sequence reconstruction, where the decoder in P&C is further weakened to promote the learning of the feature encoder. In Colorization [58], the skeleton sequences are treated as point clouds and action representation is learned by colorizing each joint based on its spatial and temporal orders." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 399, + 287, + 517 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 399, + 287, + 517 + ], + "spans": [ + { + "bbox": [ + 46, + 399, + 287, + 517 + ], + "type": "text", + "content": "Recently, many contrastive learning-based approaches [27, 48, 23, 49, 59, 34] have emerged, showing superior performance compared to earlier works. To learn better 3D action representation, they either try to dig helpful supervision across different skeleton modalities [23, 34], or explore better action data augmentation [49] and positive sample mining strategies [59]. Nevertheless, as a global feature learner originally designed for images, contrastive learning lacks explicit constraints on the exploration of temporal motion context, limiting its further development for 3D actions." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 518, + 287, + 625 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 518, + 287, + 625 + ], + "spans": [ + { + "bbox": [ + 46, + 518, + 287, + 625 + ], + "type": "text", + "content": "SkeletonMAE [53] first introduces the idea of MAE[17] into transformer-based 3D action representation learning, where the original joint coordinates of masked regions are predicted. In our approach, we demonstrate that such a self-reconstruction objective is sub-optimal for learning 3D action representation. Therefore, we introduce the Masked Motion Prediction (MAMP) framework for explicit contextual motion modeling, resulting in significantly better performance compared to raw skeleton reconstruction." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 635, + 190, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 635, + 190, + 647 + ], + "spans": [ + { + "bbox": [ + 47, + 635, + 190, + 647 + ], + "type": "text", + "content": "2.3. Masked Visual Prediction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 653, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 653, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 653, + 287, + 713 + ], + "type": "text", + "content": "With the development of vision transformers [4, 12, 50], the masked prediction derived from the autoencoder [1] has revived again. Similar to the BERT [11] pre-training in NLP, the input tokens are randomly masked and corresponding objectives are predicted, which can be the raw" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 72, + 545, + 263 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 263 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 263 + ], + "type": "text", + "content": "pixels [17], HOG features [52], or token ids from offline learned dVAEs [2]. Recently, there have also been attempts [45, 57] to use optical flow or temporal difference of images as the auxiliary reconstruction objectives, but inferior performance is observed when they are applied alone. This is largely attributed to the high redundancy of the raw images, where the key foreground motion is difficult to be pre-extracted accurately. In our approach, we employ the idea of masked visual prediction for 3D action representation learning, with the temporal skeleton motion adopted as the only reconstruction target. Different from images, the explicit temporal correspondence of joints in the human skeleton sequence enables the ready extraction of their accurate motion context. Furthermore, we also incorporate motion intensity as the semantic richness prior to guide the masking process." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 275, + 385, + 288 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 275, + 385, + 288 + ], + "spans": [ + { + "bbox": [ + 306, + 275, + 385, + 288 + ], + "type": "text", + "content": "3. Our Method" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 296, + 373, + 307 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 296, + 373, + 307 + ], + "spans": [ + { + "bbox": [ + 306, + 296, + 373, + 307 + ], + "type": "text", + "content": "3.1. Overview" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "spans": [ + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "type": "text", + "content": "Figure 2 illustrates the overall pipeline of our proposed Masked Motion Prediction (MAMP) framework. It takes a skeleton sequence " + }, + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "type": "inline_equation", + "content": "S \\in \\mathbb{R}^{T_s \\times V \\times C_s}" + }, + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "type": "text", + "content": " as input, which is randomly cropped from the original data and is resized to a fixed temporal length " + }, + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "type": "inline_equation", + "content": "T_s" + }, + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "type": "inline_equation", + "content": "V" + }, + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "type": "inline_equation", + "content": "C_s" + }, + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "type": "text", + "content": " are the number of joints and coordinate channels, respectively. The motion sequence " + }, + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "type": "inline_equation", + "content": "M \\in \\mathbb{R}^{T_s \\times V \\times C_s}" + }, + { + "bbox": [ + 304, + 314, + 545, + 422 + ], + "type": "text", + "content": " of the input is also extracted, which is defined as the differential on temporal dimension (manually padded for the first frame)." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 422, + 545, + 589 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 422, + 545, + 589 + ], + "spans": [ + { + "bbox": [ + 304, + 422, + 545, + 589 + ], + "type": "text", + "content": "As in most vision transformers, the input joints are linearly mapped into joint embedding " + }, + { + "bbox": [ + 304, + 422, + 545, + 589 + ], + "type": "inline_equation", + "content": "E \\in \\mathbb{R}^{T_e \\times V \\times C_e}" + }, + { + "bbox": [ + 304, + 422, + 545, + 589 + ], + "type": "text", + "content": ". After that, the motion-aware masking strategy is applied to mask most of the embedding features under the guidance of temporal motion intensity. The remaining features are processed by the encoder-decoder architecture, where the transformer encoder learns representation from unmasked joint embedding and the transformer decoder performs contextual modeling based on the learnable mask tokens and latent representation from the transformer encoder. Different from MAE [17] that reconstructs the original signal for representation learning, in MAMP, a motion prediction head is adopted, which takes decoded features as input and predicts the temporal motion of the input skeleton sequence." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 590, + 545, + 626 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 590, + 545, + 626 + ], + "spans": [ + { + "bbox": [ + 304, + 590, + 545, + 626 + ], + "type": "text", + "content": "After the aforementioned pre-training, only the joint embedding layer and the transformer encoder are reserved for downstream applications." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 635, + 409, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 635, + 409, + 647 + ], + "spans": [ + { + "bbox": [ + 306, + 635, + 409, + 647 + ], + "type": "text", + "content": "3.2. Joint Embedding" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "In most transformer-based attempts [35, 41, 36], each spatio-temporal skeleton joint is embedded separately, resulting in a large number of input tokens. Considering the temporal redundancy, in our approach, the input skeleton sequence " + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "inline_equation", + "content": "S \\in \\mathbb{R}^{T_s \\times V \\times C_s}" + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": " is divided into temporally non" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10183" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 70, + 547, + 214 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 547, + 214 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 547, + 214 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 547, + 214 + ], + "type": "image", + "image_path": "143a150f455a8b964d76bd570a1c774e28c1e45e014ed5486ec7457b324ee9f3.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 217, + 547, + 262 + ], + "lines": [ + { + "bbox": [ + 46, + 217, + 547, + 262 + ], + "spans": [ + { + "bbox": [ + 46, + 217, + 547, + 262 + ], + "type": "text", + "content": "Figure 2. The overall pipeline of the proposed MAMP framework. Different from the self-reconstruction scheme adopted in previous works [62, 53], our MAMP learns 3D action representation by predicting the corresponding motion sequence for masked joint input. Moreover, motion information also acts as an empirical semantic richness prior that effectively guides the masking process, enabling more attention to be applied to regions with significant temporal motion intensity." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 282, + 287, + 319 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 282, + 287, + 319 + ], + "spans": [ + { + "bbox": [ + 46, + 282, + 287, + 319 + ], + "type": "text", + "content": "overlapping segments " + }, + { + "bbox": [ + 46, + 282, + 287, + 319 + ], + "type": "inline_equation", + "content": "S' \\in \\mathbb{R}^{T_e \\times V \\times l \\times C_s}" + }, + { + "bbox": [ + 46, + 282, + 287, + 319 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 282, + 287, + 319 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 46, + 282, + 287, + 319 + ], + "type": "text", + "content": " is the length of each segment and " + }, + { + "bbox": [ + 46, + 282, + 287, + 319 + ], + "type": "inline_equation", + "content": "T_e = T_s / l" + }, + { + "bbox": [ + 46, + 282, + 287, + 319 + ], + "type": "text", + "content": ". In each segment, joints with the same spatial position are embedded together:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 86, + 329, + 287, + 344 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 86, + 329, + 287, + 344 + ], + "spans": [ + { + "bbox": [ + 86, + 329, + 287, + 344 + ], + "type": "interline_equation", + "content": "E = \\operatorname {J o i n t E m b e d} \\left(S ^ {\\prime}\\right) \\in \\mathbb {R} ^ {T _ {e} \\times V \\times C _ {e}}, \\tag {1}", + "image_path": "edbc1db2f61773fd1a61bcbf14049c1ff77fee694177892d9ec2449971825400.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 348, + 287, + 397 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 348, + 287, + 397 + ], + "spans": [ + { + "bbox": [ + 47, + 348, + 287, + 397 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 348, + 287, + 397 + ], + "type": "inline_equation", + "content": "C_e" + }, + { + "bbox": [ + 47, + 348, + 287, + 397 + ], + "type": "text", + "content": " is the dimension of the embedding features. Compared to the original skeleton sequence, the temporal resolution of the embedding " + }, + { + "bbox": [ + 47, + 348, + 287, + 397 + ], + "type": "inline_equation", + "content": "E" + }, + { + "bbox": [ + 47, + 348, + 287, + 397 + ], + "type": "text", + "content": " is reduced by a factor of " + }, + { + "bbox": [ + 47, + 348, + 287, + 397 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 47, + 348, + 287, + 397 + ], + "type": "text", + "content": ", resulting in higher computational efficiency." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 403, + 157, + 415 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 403, + 157, + 415 + ], + "spans": [ + { + "bbox": [ + 47, + 403, + 157, + 415 + ], + "type": "text", + "content": "3.3. Motion Extraction" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 422, + 287, + 483 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 422, + 287, + 483 + ], + "spans": [ + { + "bbox": [ + 47, + 422, + 287, + 483 + ], + "type": "text", + "content": "Different from RGB frames with heavy spatial redundancy, the human skeleton sequence is highly semantic, with explicit correspondence between neighboring frames. Therefore, we can easily obtain its motion " + }, + { + "bbox": [ + 47, + 422, + 287, + 483 + ], + "type": "inline_equation", + "content": "M \\in \\mathbb{R}^{T_s \\times V \\times C_s}" + }, + { + "bbox": [ + 47, + 422, + 287, + 483 + ], + "type": "text", + "content": " by applying temporal difference on joint coordinates:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 491, + 287, + 506 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 491, + 287, + 506 + ], + "spans": [ + { + "bbox": [ + 53, + 491, + 287, + 506 + ], + "type": "interline_equation", + "content": "M _ {i,:,:} = S _ {i,:,:} - S _ {i - m,:,:}, i \\in m, m + 1, \\dots , T _ {s} - 1, \\tag {2}", + "image_path": "0832048ff4ca37293095b85a6904a3e25f8ae399cbbd5dae6094f1d69d90436d.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 514, + 287, + 550 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 514, + 287, + 550 + ], + "spans": [ + { + "bbox": [ + 47, + 514, + 287, + 550 + ], + "type": "text", + "content": "where stride " + }, + { + "bbox": [ + 47, + 514, + 287, + 550 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 47, + 514, + 287, + 550 + ], + "type": "text", + "content": " controls the step size of the motion. For convenience, the motion sequence is padded to be consistent with the length of the original input:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 75, + 558, + 287, + 583 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 75, + 558, + 287, + 583 + ], + "spans": [ + { + "bbox": [ + 75, + 558, + 287, + 583 + ], + "type": "interline_equation", + "content": "M _ {0: m - 1,:,:} = \\left\\{ \\begin{array}{l l} 0, & \\text {c o n s t a n t} \\\\ M _ {m: 2 m - 1,:,:}, & \\text {r e p l i c a t e} \\end{array} , \\right. \\tag {3}", + "image_path": "b6f38b8cd7636729c920b45c6b844e7371e5b65020fe54880bca9265cd2028f9.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 592, + 287, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 592, + 287, + 628 + ], + "spans": [ + { + "bbox": [ + 47, + 592, + 287, + 628 + ], + "type": "text", + "content": "where constant and replicate denote constant padding (with zeros) and replicate padding for the first " + }, + { + "bbox": [ + 47, + 592, + 287, + 628 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 47, + 592, + 287, + 628 + ], + "type": "text", + "content": " frames of the motion sequence, respectively." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 635, + 181, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 635, + 181, + 647 + ], + "spans": [ + { + "bbox": [ + 47, + 635, + 181, + 647 + ], + "type": "text", + "content": "3.4. Motion-Aware Masking" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 654, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 654, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 47, + 654, + 287, + 714 + ], + "type": "text", + "content": "In the proposed approach, the motion information is used not only as the reconstruction target during pre-training but also as the empirical semantic richness prior that guiding the masking of embedding features. Considering that the skeleton sequence is segment-wise embedded with length " + }, + { + "bbox": [ + 47, + 654, + 287, + 714 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 47, + 654, + 287, + 714 + ], + "type": "text", + "content": "," + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "spans": [ + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "type": "text", + "content": "we extract the motion sequence " + }, + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "type": "inline_equation", + "content": "M^{\\mathrm{mask}} \\in \\mathbb{R}^{T_i \\times V \\times C_i}" + }, + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "type": "text", + "content": " with stride " + }, + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "type": "inline_equation", + "content": "m = l" + }, + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "type": "text", + "content": " and replicate padding according to Eq. (2) and Eq. (3), which is further reshaped into " + }, + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "type": "inline_equation", + "content": "M' \\in \\mathbb{R}^{T_e \\times V \\times l \\times C_i}" + }, + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "type": "text", + "content": " as is done for " + }, + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "type": "inline_equation", + "content": "S'" + }, + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "type": "text", + "content": ". Then, the motion intensity " + }, + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 304, + 282, + 545, + 354 + ], + "type": "text", + "content": ", which indicates the motion significance of each spatio-temporal segment, is computed as follows:" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 359, + 361, + 545, + 396 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 359, + 361, + 545, + 396 + ], + "spans": [ + { + "bbox": [ + 359, + 361, + 545, + 396 + ], + "type": "interline_equation", + "content": "I = \\sum_ {i = 0} ^ {l} \\sum_ {j = 0} ^ {C _ {i}} \\left| M _ {:,:,: i, j} ^ {\\prime} \\right| \\in \\mathbb {R} ^ {T _ {e} \\times V}. \\tag {4}", + "image_path": "aa435e5011ca507daeae1e7770ea82af0f7e6bffc97cbfb3aa66be7d790b4dd1.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 402, + 545, + 462 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 402, + 545, + 462 + ], + "spans": [ + { + "bbox": [ + 304, + 402, + 545, + 462 + ], + "type": "text", + "content": "Since human actions are composed of a series of temporal movements, we argue that the intensity of motion largely reflects the semantic richness. Therefore in MAMP, the motion intensity is further converted into probability distribution with a temperature hyper-parameter " + }, + { + "bbox": [ + 304, + 402, + 545, + 462 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 304, + 402, + 545, + 462 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 380, + 469, + 545, + 483 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 380, + 469, + 545, + 483 + ], + "spans": [ + { + "bbox": [ + 380, + 469, + 545, + 483 + ], + "type": "interline_equation", + "content": "\\pi = \\operatorname {S o f t m a x} (I / \\tau), \\tag {5}", + "image_path": "03b5fa8bf3104b32a1dbb26f1cb3df256e8bdbe4deede51924f46799e2e0f886.jpg" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 489, + 545, + 525 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 489, + 545, + 525 + ], + "spans": [ + { + "bbox": [ + 304, + 489, + 545, + 525 + ], + "type": "text", + "content": "which indicates the probability that each embedding feature is masked. In MAMP, the idea of gumble max is adapted for efficient probability-guided mask index sampling:" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 337, + 531, + 545, + 562 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 337, + 531, + 545, + 562 + ], + "spans": [ + { + "bbox": [ + 337, + 531, + 545, + 562 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} g = - \\log (- \\log \\epsilon), \\epsilon \\in U [ 0, 1 ] ^ {T _ {\\epsilon} \\times V}, \\\\ i d x ^ {\\text {m a s k}} = \\text {I n d e x - o f - T o p - K} (\\log \\pi + g), \\tag {6} \\\\ \\end{array}", + "image_path": "1e7601ae054c6852ae67dd4555106a61f5039fb848dc9e35d5e224ea28f829c1.jpg" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 568, + 545, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 568, + 545, + 640 + ], + "spans": [ + { + "bbox": [ + 304, + 568, + 545, + 640 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 568, + 545, + 640 + ], + "type": "inline_equation", + "content": "U[0,1]" + }, + { + "bbox": [ + 304, + 568, + 545, + 640 + ], + "type": "text", + "content": " denotes uniform distribution between 0 and 1. The obtained " + }, + { + "bbox": [ + 304, + 568, + 545, + 640 + ], + "type": "inline_equation", + "content": "idx^{\\mathrm{mask}}" + }, + { + "bbox": [ + 304, + 568, + 545, + 640 + ], + "type": "text", + "content": " indicates which joints are masked and is used for unmasked token selection in Section 3.5. Based on the above operations, the network is encouraged to focus more on semantically rich regions, so as to learn more discriminative 3D action representation." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 647, + 454, + 658 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 647, + 454, + 658 + ], + "spans": [ + { + "bbox": [ + 306, + 647, + 454, + 658 + ], + "type": "text", + "content": "3.5. Masked Motion Prediction" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 665, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 714 + ], + "type": "text", + "content": "We follow the encoder-decoder design in MAE [17], where the transformer encoder focuses on representation learning, while the decoder is responsible for the implementation of the pre-training pretext." + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10184" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": "Encoder: In the encoder, separate spatio-temporal positional embedding " + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "P_{e}^{s} \\in \\mathbb{R}^{1 \\times V \\times C_{e}}" + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "P_{e}^{t} \\in \\mathbb{R}^{T_{e} \\times 1 \\times C_{e}}" + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": " are first element-wise added (with broadcasting) to the input joint embedding " + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "E" + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 123, + 125, + 287, + 138 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 123, + 125, + 287, + 138 + ], + "spans": [ + { + "bbox": [ + 123, + 125, + 287, + 138 + ], + "type": "interline_equation", + "content": "E _ {p} = E + P _ {e} ^ {s} + P _ {e} ^ {t}. \\tag {7}", + "image_path": "22a380d9d9626505e3d1561729442bd8fa2698b2bacf2e8d406f75bb1221a48e.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "spans": [ + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "type": "text", + "content": "Then, the unmasked tokens in " + }, + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "type": "inline_equation", + "content": "E_{p}" + }, + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "type": "text", + "content": " are selected according to the " + }, + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "type": "inline_equation", + "content": "idx^{\\mathrm{mask}}" + }, + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "type": "text", + "content": " extracted in Eq. (6) and are flattened to " + }, + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "type": "inline_equation", + "content": "E_{p}^{u} \\in \\mathbb{R}^{N_{u} \\times C_{e}}" + }, + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "type": "inline_equation", + "content": "N_{u} = T_{e} \\times V \\times (1 - \\mathrm{mask~ratio})" + }, + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "type": "text", + "content": " is the number of unmasked tokens. After that, the latent representation is extracted by " + }, + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "type": "inline_equation", + "content": "L_{e}" + }, + { + "bbox": [ + 47, + 143, + 287, + 202 + ], + "type": "text", + "content": " vanilla transformer blocks:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 63, + 207, + 108, + 221 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 207, + 108, + 221 + ], + "spans": [ + { + "bbox": [ + 63, + 207, + 108, + 221 + ], + "type": "interline_equation", + "content": "H _ {0} = E _ {p} ^ {u},", + "image_path": "6e3a8baf7d3cd54efdb5db816a42cd5d75bbe78fadad27abf3d806af00a4beb5.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 65, + 223, + 287, + 242 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 223, + 287, + 242 + ], + "spans": [ + { + "bbox": [ + 65, + 223, + 287, + 242 + ], + "type": "interline_equation", + "content": "H _ {l} ^ {\\prime} = \\operatorname {M S A} \\left(\\ln \\left(H _ {l - 1}\\right)\\right) + H _ {l - 1}, \\quad l \\in 1, \\dots , L _ {e} \\tag {8}", + "image_path": "4ed8f01ce9cf35d9a211c4a32c8305bed4beeaadfecdf867ab821bcdaf9af6c1.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 65, + 238, + 277, + 251 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 238, + 277, + 251 + ], + "spans": [ + { + "bbox": [ + 65, + 238, + 277, + 251 + ], + "type": "interline_equation", + "content": "H _ {l} = \\operatorname {M L P} \\left(\\operatorname {L N} \\left(H _ {l} ^ {\\prime}\\right)\\right) + H _ {l} ^ {\\prime}, \\quad l \\in 1, \\dots , L _ {e}", + "image_path": "886d8053ad5aa95ed05ebe4b66cfeb1e14bcccc469272ec4050531781705e563.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 63, + 254, + 133, + 266 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 254, + 133, + 266 + ], + "spans": [ + { + "bbox": [ + 63, + 254, + 133, + 266 + ], + "type": "interline_equation", + "content": "H _ {e} ^ {u} = \\mathrm {L N} \\left(H _ {L _ {e}}\\right),", + "image_path": "06f5da28a46e2ce0458917996bd4397f968d046760c666ebca3d92892f2e3bd7.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 270, + 286, + 294 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 270, + 286, + 294 + ], + "spans": [ + { + "bbox": [ + 46, + 270, + 286, + 294 + ], + "type": "text", + "content": "where MSA, MLP, and LN denote multi-head self-attention, multilayer perceptron, and layer norm, respectively." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 294, + 287, + 342 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 294, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 46, + 294, + 287, + 342 + ], + "type": "text", + "content": "Decoder: In the decoder, the learnable mask tokens are inserted into " + }, + { + "bbox": [ + 46, + 294, + 287, + 342 + ], + "type": "inline_equation", + "content": "H_{e}^{u}" + }, + { + "bbox": [ + 46, + 294, + 287, + 342 + ], + "type": "text", + "content": " according to the mask indices " + }, + { + "bbox": [ + 46, + 294, + 287, + 342 + ], + "type": "inline_equation", + "content": "idx^{\\mathrm{mask}}" + }, + { + "bbox": [ + 46, + 294, + 287, + 342 + ], + "type": "text", + "content": ". The result is reshaped back to " + }, + { + "bbox": [ + 46, + 294, + 287, + 342 + ], + "type": "inline_equation", + "content": "H_{e} \\in \\mathbb{R}^{T_{e} \\times V \\times C_{e}}" + }, + { + "bbox": [ + 46, + 294, + 287, + 342 + ], + "type": "text", + "content": ", which is processed by " + }, + { + "bbox": [ + 46, + 294, + 287, + 342 + ], + "type": "inline_equation", + "content": "L_{d}" + }, + { + "bbox": [ + 46, + 294, + 287, + 342 + ], + "type": "text", + "content": " decoder layers for masked modeling:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 64, + 346, + 156, + 360 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 64, + 346, + 156, + 360 + ], + "spans": [ + { + "bbox": [ + 64, + 346, + 156, + 360 + ], + "type": "interline_equation", + "content": "Z _ {0} = H _ {e} + P _ {d} ^ {s} + P _ {d} ^ {t},", + "image_path": "903a4e376b2e2f6ab360e1429b5dcc28968b6204e9e33c1ad8d2015d48d6d9a2.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 66, + 361, + 287, + 381 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 361, + 287, + 381 + ], + "spans": [ + { + "bbox": [ + 66, + 361, + 287, + 381 + ], + "type": "interline_equation", + "content": "Z _ {l} ^ {\\prime} = \\operatorname {M S A} \\left(\\ln \\left(Z _ {l - 1}\\right)\\right) + Z _ {l - 1}, \\quad l \\in 1, \\dots , L _ {d} \\tag {9}", + "image_path": "fec59ae9be74468804cf3d74353a6f41dbd6fed062e1781b7e04c31495adeb06.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 66, + 376, + 287, + 390 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 376, + 287, + 390 + ], + "spans": [ + { + "bbox": [ + 66, + 376, + 287, + 390 + ], + "type": "interline_equation", + "content": "Z _ {l} = \\operatorname {M L P} \\left(\\ln \\left(Z _ {l} ^ {\\prime}\\right)\\right) + Z _ {l} ^ {\\prime}, \\quad l \\in 1, \\dots , L _ {d}", + "image_path": "4a0b5aa1e584d841d25fbd764ff6b8418cfefc054e35f200d90e0d2fbdbf890e.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 66, + 392, + 131, + 405 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 392, + 131, + 405 + ], + "spans": [ + { + "bbox": [ + 66, + 392, + 131, + 405 + ], + "type": "interline_equation", + "content": "Z _ {d} = \\operatorname {L N} \\left(Z _ {L _ {d}}\\right),", + "image_path": "f68a128a8d9b162fb0b6e6915ef57de7ba913d005eee5be218637b776e5633ff.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 410, + 287, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 410, + 287, + 434 + ], + "spans": [ + { + "bbox": [ + 46, + 410, + 287, + 434 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 410, + 287, + 434 + ], + "type": "inline_equation", + "content": "P_{d}^{s}" + }, + { + "bbox": [ + 46, + 410, + 287, + 434 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 410, + 287, + 434 + ], + "type": "inline_equation", + "content": "P_{d}^{t}" + }, + { + "bbox": [ + 46, + 410, + 287, + 434 + ], + "type": "text", + "content": " are the spatial and temporal positional embedding of the transformer decoder, respectively." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 434, + 287, + 518 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 434, + 287, + 518 + ], + "spans": [ + { + "bbox": [ + 46, + 434, + 287, + 518 + ], + "type": "text", + "content": "Motion Prediction: In our method, the reconstruction target is not the original skeletons, but the motion sequence " + }, + { + "bbox": [ + 46, + 434, + 287, + 518 + ], + "type": "inline_equation", + "content": "M^{\\mathrm{target}}" + }, + { + "bbox": [ + 46, + 434, + 287, + 518 + ], + "type": "text", + "content": " pre-extracted according to Eq. (2) and Eq. (3), which is normalized by its segment-wise mean and standard deviation as in [17]. Therefore, given the decoded feature " + }, + { + "bbox": [ + 46, + 434, + 287, + 518 + ], + "type": "inline_equation", + "content": "Z_{d} \\in \\mathbb{R}^{T_{e} \\times V \\times C_{d}}" + }, + { + "bbox": [ + 46, + 434, + 287, + 518 + ], + "type": "text", + "content": ", we additionally adopt a prediction head to predict the temporal motion of masked human joints:" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 94, + 522, + 287, + 536 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 94, + 522, + 287, + 536 + ], + "spans": [ + { + "bbox": [ + 94, + 522, + 287, + 536 + ], + "type": "interline_equation", + "content": "M ^ {\\text {p r e d}} = \\text {M o t i o n P r e d H e a d} \\left(Z _ {d}\\right), \\tag {10}", + "image_path": "98f960b95eb14fcf68e7a8c13543585b3870aed35ccb0967e79e290d79a53177.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 46, + 540, + 287, + 589 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 540, + 287, + 589 + ], + "spans": [ + { + "bbox": [ + 46, + 540, + 287, + 589 + ], + "type": "text", + "content": "where we empirically find that a simple fully connected layer just works well. For masked human joints, we compute the mean squared error (MSE) between the predicted result " + }, + { + "bbox": [ + 46, + 540, + 287, + 589 + ], + "type": "inline_equation", + "content": "M^{\\mathrm{pred}}" + }, + { + "bbox": [ + 46, + 540, + 287, + 589 + ], + "type": "text", + "content": " and the reconstruction target " + }, + { + "bbox": [ + 46, + 540, + 287, + 589 + ], + "type": "inline_equation", + "content": "M^{\\mathrm{target}}" + }, + { + "bbox": [ + 46, + 540, + 287, + 589 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 61, + 593, + 287, + 622 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 593, + 287, + 622 + ], + "spans": [ + { + "bbox": [ + 61, + 593, + 287, + 622 + ], + "type": "interline_equation", + "content": "\\mathcal {L} = \\frac {1}{| i d x ^ {\\text {m a s k}} |} \\sum_ {(i, j) \\in i d x ^ {\\text {m a s k}}} \\| \\left(M _ {i, j,:} ^ {\\text {p r e d}} - M _ {i, j,:} ^ {\\text {t a r g e t}}\\right) \\| _ {2} ^ {2}. \\tag {11}", + "image_path": "8cd0eb0514b1deeae560f4153a550b717cad3bafce80129771aeff668f42e740.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 47, + 628, + 127, + 640 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 628, + 127, + 640 + ], + "spans": [ + { + "bbox": [ + 47, + 628, + 127, + 640 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 47, + 647, + 230, + 658 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 647, + 230, + 658 + ], + "spans": [ + { + "bbox": [ + 47, + 647, + 230, + 658 + ], + "type": "text", + "content": "4.1. Datasets and Evaluation Protocols" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "type": "text", + "content": "NTU-RGB+D 60 [38]: NTU-RGB+D 60 (NTU-60) is a large-scale dataset for human action recognition. It contains 60 action categories performed by 40 different subjects, with a total of 56,880 3D skeleton sequences. In this" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": "paper, we adopt the evaluation protocols recommended by the authors, namely cross-subject (X-sub) and cross-view (X-view). The former, X-sub uses the action sequences performed by half of the 40 subjects as training samples and the rest as test samples. For X-view, the training samples are action sequences captured by cameras 2 and 3, and the test samples are those captured by camera 1." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 156, + 545, + 287 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 156, + 545, + 287 + ], + "spans": [ + { + "bbox": [ + 304, + 156, + 545, + 287 + ], + "type": "text", + "content": "NTU-RGB+D 120 [28]: NTU-RGB+D 120 (NTU120) is an extended version of NTU-60, in which the number of action categories is increased from 60 to 120, the number of total skeleton sequences and subjects are also increased to 114,480 and 106, respectively. Furthermore, the authors also introduce a more challenging evaluation protocol named cross-setup (X-set) to substitute for the original X-view in NTU-60. Specifically, X-set divides sequences into 32 different setups based on the camera distance and background. Samples from half of these setups are used as the training set and the remainder constitute the test set." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 289, + 545, + 408 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 289, + 545, + 408 + ], + "spans": [ + { + "bbox": [ + 304, + 289, + 545, + 408 + ], + "type": "text", + "content": "PKU-MMD [9]: Following [48], to perform 3D action classification on PKU-MMD, we crop out action instances based on temporal annotations and divide them into training and test sets according to the cross-subject protocol. PKU-MMD contains two phases: PKU-MMD I (PKU-I) and PKU-MMD II (PKU-II). In PKU-I, the number of samples in training and test sets are 18,841 and 2,704, respectively. Due to the more noise introduced by the larger view variation, PKU-II is more challenging, with 5,332 samples for training and 1,613 for testing." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 306, + 418, + 422, + 430 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 418, + 422, + 430 + ], + "spans": [ + { + "bbox": [ + 306, + 418, + 422, + 430 + ], + "type": "text", + "content": "4.2. Experimental Setup" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 304, + 437, + 545, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 437, + 545, + 568 + ], + "spans": [ + { + "bbox": [ + 304, + 437, + 545, + 568 + ], + "type": "text", + "content": "Network Architecture: In our MAMP framework, we adopt a vanilla vision transformer [12] as the backbone network, which consists of " + }, + { + "bbox": [ + 304, + 437, + 545, + 568 + ], + "type": "inline_equation", + "content": "L_{e} = 8" + }, + { + "bbox": [ + 304, + 437, + 545, + 568 + ], + "type": "text", + "content": " identical building blocks. In each block, the embedding dimension is 256, the head number of the multi-head self-attention module is 8, and the hidden dimension of the feed-forward network is 1024. We employ learnable spatio-temporal separated positional embedding to the embedded inputs. The settings of the transformer decoder used during pre-training are consistent with those of the backbone encoder except that the number of layers " + }, + { + "bbox": [ + 304, + 437, + 545, + 568 + ], + "type": "inline_equation", + "content": "L_{d}" + }, + { + "bbox": [ + 304, + 437, + 545, + 568 + ], + "type": "text", + "content": " is reduced to 5." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 304, + 569, + 545, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 569, + 545, + 640 + ], + "spans": [ + { + "bbox": [ + 304, + 569, + 545, + 640 + ], + "type": "text", + "content": "Data Processing Details: Given an original skeleton sequence, a contiguous segment is first randomly cropped from it with a certain proportion " + }, + { + "bbox": [ + 304, + 569, + 545, + 640 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 304, + 569, + 545, + 640 + ], + "type": "text", + "content": " (" + }, + { + "bbox": [ + 304, + 569, + 545, + 640 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 304, + 569, + 545, + 640 + ], + "type": "text", + "content": " is sampled from [0.5,1] during training and fixed to 0.9 during the test). After that, the cropped segment is resized to a fixed length " + }, + { + "bbox": [ + 304, + 569, + 545, + 640 + ], + "type": "inline_equation", + "content": "T_{s}" + }, + { + "bbox": [ + 304, + 569, + 545, + 640 + ], + "type": "text", + "content": " by bilinear interpolation. " + }, + { + "bbox": [ + 304, + 569, + 545, + 640 + ], + "type": "inline_equation", + "content": "T_{s}" + }, + { + "bbox": [ + 304, + 569, + 545, + 640 + ], + "type": "text", + "content": " is set to 120 by default." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": "Pre-training Details: During pre-training, the masking ratio of the input token is set to " + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "inline_equation", + "content": "90\\%" + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": ". The target motion sequence " + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "inline_equation", + "content": "M^{\\mathrm{target}}" + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": " has stride " + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "inline_equation", + "content": "m = 1" + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": " and is padded with zeros. We adopt the AdamW [33] optimizer with a weight decay of 0.05 and betas of (0.9, 0.95). We pre-train the network for 400 epochs with a batch size of 128. The learning rate" + } + ] + } + ], + "index": 27 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10185" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 49, + 70, + 542, + 255 + ], + "blocks": [ + { + "bbox": [ + 49, + 70, + 542, + 255 + ], + "lines": [ + { + "bbox": [ + 49, + 70, + 542, + 255 + ], + "spans": [ + { + "bbox": [ + 49, + 70, + 542, + 255 + ], + "type": "table", + "html": "
MethodInput streamNTU-60NTU-120PKU-MMD
X-subX-viewX-subX-setPhase IPhase II
3s-SkeletonCLR [23]Joint+Motion+Bone75.079.860.762.685.3-
3s-CrosSCLR [23]Joint+Motion+Bone77.883.467.966.784.921.2
3s-AimCLR [49]Joint+Motion+Bone78.983.868.268.887.439.5
LongT GAN [62]Joint only39.148.1--67.726.0
P&C [46]Joint only50.776.342.741.759.925.5
MS2L [27]Joint only52.6---64.927.6
AS-CAL [37]Joint only58.564.848.649.2--
ISC [48]Joint only76.385.267.167.980.936.0
GL-Transformer [20]Joint only76.383.866.068.7--
CPM [59]Joint only78.784.968.769.688.848.3
CMD [34]Joint only79.486.970.371.5-43.0
SkeletonMAE* [53]Joint only74.877.772.573.582.836.1
MAMP (Ours)Joint only84.989.178.679.192.253.8
", + "image_path": "24b554f11c4062f338fa57517aff19c7396076438b8bcfbe196ced8e2b76f596.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 49, + 291, + 282, + 474 + ], + "blocks": [ + { + "bbox": [ + 47, + 257, + 546, + 281 + ], + "lines": [ + { + "bbox": [ + 47, + 257, + 546, + 281 + ], + "spans": [ + { + "bbox": [ + 47, + 257, + 546, + 281 + ], + "type": "text", + "content": "Table 1. Performance comparison on the NTU-60, NTU-120, and PKU-MMD datasets under the linear evaluation protocol. * indicates the re-implemented version under our framework, where improved performance is achieved." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 49, + 291, + 282, + 474 + ], + "lines": [ + { + "bbox": [ + 49, + 291, + 282, + 474 + ], + "spans": [ + { + "bbox": [ + 49, + 291, + 282, + 474 + ], + "type": "table", + "html": "
MethodBackboneNTU-60
X-subX-view
CPM [59]ST-GCN84.891.1
CrossCLR [23]3s-ST-GCN86.292.5
AimCLR [49]3s-ST-GCN86.992.8
CrossCLR [23]STTFormer84.690.5
AimCLR [49]STTFormer83.990.4
SkeletonMAE [53]STTFormer86.692.9
Colorization [58]3s-DGCNN88.094.9
MCC [47]2s-AGCN89.796.3
ViA [56]2s-UINK89.696.4
Hi-TRS [6]3s-Transformer90.095.7
W/o pre-trainingTransformer83.192.6
SkeletonMAE* [53]Transformer88.594.7
MAMP (Ours)Transformer93.197.5
", + "image_path": "700861410cbd8fec26af37c07e759b6ea81abdaff2ae8fefc506acc8f9044b2b.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 520, + 287, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 520, + 287, + 568 + ], + "spans": [ + { + "bbox": [ + 46, + 520, + 287, + 568 + ], + "type": "text", + "content": "is linearly increased to 1e-3 from 0 in the first 20 warm-up epochs and then decreased to 5e-4 by the cosine decay schedule. The experiments are conducted using the PyTorch framework on four NVIDIA RTX 3090 GPUs." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 575, + 270, + 588 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 575, + 270, + 588 + ], + "spans": [ + { + "bbox": [ + 47, + 575, + 270, + 588 + ], + "type": "text", + "content": "4.3. Comparison with State-of-the-art Methods" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 594, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 287, + 713 + ], + "type": "text", + "content": "Linear Evaluation Results: In linear evaluation protocol, the pre-trained backbone is fixed and a post-attached linear classifier is trained with supervision for 100 epochs with a batch size of 256 and a learning rate of 0.1. The learning rate is decreased to 0 by the cosine decay schedule. As shown in Table 1, the performance on three datasets are reported, they are NTU-60, NTU-120, and PKU-MMD, respectively. We include latest high-performance approaches for comparison, e.g., GL-Transformer [20], CPM [59], CMD [34], 3s-CrosSLR [23], and 3s-AimCLR [49]. As" + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 309, + 291, + 541, + 462 + ], + "blocks": [ + { + "bbox": [ + 47, + 477, + 287, + 500 + ], + "lines": [ + { + "bbox": [ + 47, + 477, + 287, + 500 + ], + "spans": [ + { + "bbox": [ + 47, + 477, + 287, + 500 + ], + "type": "text", + "content": "Table 2. Performance comparison on the NTU-60 dataset under the fine-tuned evaluation protocol." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 309, + 291, + 541, + 462 + ], + "lines": [ + { + "bbox": [ + 309, + 291, + 541, + 462 + ], + "spans": [ + { + "bbox": [ + 309, + 291, + 541, + 462 + ], + "type": "table", + "html": "
MethodBackboneNTU-120
X-subX-set
CPM [59]ST-GCN78.478.9
CrosCLR [23]3s-ST-GCN80.580.4
AimCLR [49]3s-ST-GCN80.180.9
CrosCLR [23]STTFormer75.077.9
AimCLR [49]STTFormer74.677.2
SkeletonMAE [53]STTFormer76.879.1
MCC [47]2s-AGCN81.383.3
ViA [56]2s-UINK85.086.5
Hi-TRS [6]3s-Transformer85.387.4
W/o pre-trainingTransformer76.879.7
SkeletonMAE* [53]Transformer87.088.9
MAMP (Ours)Transformer90.091.3
", + "image_path": "8dee45f3f9e304360d6d06cdde8642984d6265f219e58ae3446d2c6bc1ef8b0b.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 310, + 503, + 539, + 579 + ], + "blocks": [ + { + "bbox": [ + 306, + 465, + 545, + 489 + ], + "lines": [ + { + "bbox": [ + 306, + 465, + 545, + 489 + ], + "spans": [ + { + "bbox": [ + 306, + 465, + 545, + 489 + ], + "type": "text", + "content": "Table 3. Performance comparison on the NTU-120 dataset under the fine-tuned evaluation protocol." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 310, + 503, + 539, + 579 + ], + "lines": [ + { + "bbox": [ + 310, + 503, + 539, + 579 + ], + "spans": [ + { + "bbox": [ + 310, + 503, + 539, + 579 + ], + "type": "table", + "html": "
MethodNTU-60NTU-120
X-subX-viewX-subX-set
PoseC3D [15]93.796.686.089.6
CTR-CGN [5]92.496.888.990.6
InfoGCN [8]93.097.189.891.2
MAMP (Ours)93.197.590.091.3
", + "image_path": "26a3cb984d2703734b9f8c0e1a6165f2955be8d813a684de8d0480976b16e745.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 582, + 545, + 616 + ], + "lines": [ + { + "bbox": [ + 305, + 582, + 545, + 616 + ], + "spans": [ + { + "bbox": [ + 305, + 582, + 545, + 616 + ], + "type": "text", + "content": "Table 4. Performance comparison with fully-supervised methods on the NTU-60 and NTU-120 datasets. Note that our MAMP does not perform multi-stream ensembling during evaluation." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": "we can see, with the joint stream as the only input, our proposed MAMP outperforms these methods on all the datasets. Specifically, MAMP outperforms previous state-of-the-art method CMD by " + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "inline_equation", + "content": "5.5\\%" + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "inline_equation", + "content": "8.3\\%" + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": " on the challenging NTU-60 x-sub and NTU-120 x-sub, respectively. For a fair comparison, we also re-implement the Skeleton" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "10186" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 288, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 288, + 144 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 288, + 144 + ], + "type": "text", + "content": "MAE [53] under the same settings as our approach (denote as SkeletonMAE*), where improved performance is achieved. We can find that our MAMP significantly outperforms SkeletonMAE* on all six subsets of the three datasets, demonstrating the superiority of masked motion prediction compared to the self-reconstruction of joints." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 145, + 290, + 397 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 145, + 290, + 397 + ], + "spans": [ + { + "bbox": [ + 46, + 145, + 290, + 397 + ], + "type": "text", + "content": "Fine-tuned Evaluation Results: In fine-tuned evaluation protocol, an MLP head is attached to the pre-trained backbone and the whole network is fully fine-tuned for 100 epochs with a batch size of 48. The learning rate is linearly increased to 3e-4 from 0 in the first 5 warm-up epochs and then decreased to 1e-5 by the cosine decay schedule. We also adopt layer-wise lr decay [10] following [2]. As shown in Table 2 and Table 3, we evaluate the fine-tuned performance on NTU-60 and NTU-120, respectively. The vanilla transformer does not show satisfactory performance when trained directly from scratch, which is under expectation as weakly biased transformers require a large amount of training data to effectively prevent overfitting. After being pre-trained with the proposed MAMP framework, the network exhibits significant performance improvements ranging from " + }, + { + "bbox": [ + 46, + 145, + 290, + 397 + ], + "type": "inline_equation", + "content": "5\\%" + }, + { + "bbox": [ + 46, + 145, + 290, + 397 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 145, + 290, + 397 + ], + "type": "inline_equation", + "content": "13\\%" + }, + { + "bbox": [ + 46, + 145, + 290, + 397 + ], + "type": "text", + "content": " on the four subsets of the NTU-60 and NTU-120 datasets. The final results exceed all previous methods, even those with multi-stream ensembling such as Colorization [58], MCC [47], and ViA [56]. Moreover, our MAMP also outperforms the re-implemented Skeleton-MAE* by a considerable margin." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 399, + 287, + 458 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 399, + 287, + 458 + ], + "spans": [ + { + "bbox": [ + 46, + 399, + 287, + 458 + ], + "type": "text", + "content": "We also compare our MAMP with the top-performing supervised methods like PoseC3D [15], CTR-GCN [5], and InfoGCN [8] in Table 4. Results show that without ensembling, MAMP outperforms most top-performing methods, especially on the larger NTU-120 dataset." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "spans": [ + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "text", + "content": "Semi-supervised Evaluation Results: Following previous works [23, 34, 48], in semi-supervised evaluation protocol, the post-attached classification layer and the pre-trained encoder are fine-tuned together with only a small fraction of the training set. Apart from that, we keep other training settings consistent with the fine-tuned evaluation protocol. As in [23, 49, 59], we report the performance on the NTU-60 dataset when using " + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "inline_equation", + "content": "1\\%" + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "text", + "content": " of the training set. Note that considering the randomness during training data selection, we report the average of five runs as the final results. As shown in Table 5, our proposed MAMP significantly outperforms previous works like 3s-AimCLR [49], CPM [59], CMD [34], and SkeletonMAE* [53]. When using only " + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "inline_equation", + "content": "1\\%" + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "text", + "content": " of the training data, MAMP outperforms SkeletonMAE* by " + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "inline_equation", + "content": "11.6\\%" + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "inline_equation", + "content": "14.0\\%" + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "text", + "content": " in X-sub and X-view respectively. Compared to training from scratch, MAMP pretraining brings performance improvements of more than " + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "inline_equation", + "content": "15.5\\%" + }, + { + "bbox": [ + 46, + 460, + 288, + 674 + ], + "type": "text", + "content": " on all subsets of NTU-60." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 677, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 289, + 715 + ], + "type": "text", + "content": "Transfer Learning Evaluation Results: In transfer learning evaluation protocol, the network is pre-trained on a source dataset and then finetuned on a different target" + } + ] + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 309, + 70, + 542, + 278 + ], + "blocks": [ + { + "bbox": [ + 309, + 70, + 542, + 278 + ], + "lines": [ + { + "bbox": [ + 309, + 70, + 542, + 278 + ], + "spans": [ + { + "bbox": [ + 309, + 70, + 542, + 278 + ], + "type": "table", + "html": "
MethodNTU-60
X-subX-view
(1%)(10%)(1%)(10%)
LongT GAN [62]35.262.0--
MS2L [27]33.165.1--
ASSL [44]-64.3-69.8
ISC [48]35.765.938.172.5
3s-CrosSCLR [23]51.174.450.077.8
3s-Colorization [58]48.371.752.578.9
CMD [34]50.675.453.080.2
3s-Hi-TRS [6]49.377.751.581.1
3s-AimCLR [49]54.878.254.381.6
3s-CMD [34]55.679.055.582.4
CPM [59]56.773.057.577.1
W/o pre-training38.870.840.476.0
SkeletonMAE* [53]54.480.654.683.5
MAMP (Ours)66.088.068.791.5
", + "image_path": "d082f9fe7a401e07ec8ede68f1f8cd93da406233e4dd61a34229d18d401e7c63.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 308, + 325, + 542, + 426 + ], + "blocks": [ + { + "bbox": [ + 305, + 281, + 547, + 315 + ], + "lines": [ + { + "bbox": [ + 305, + 281, + 547, + 315 + ], + "spans": [ + { + "bbox": [ + 305, + 281, + 547, + 315 + ], + "type": "text", + "content": "Table 5. Performance comparison on the NTU-60 dataset under the semi-supervised evaluation protocol. We report the average of five runs as the final performance." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 308, + 325, + 542, + 426 + ], + "lines": [ + { + "bbox": [ + 308, + 325, + 542, + 426 + ], + "spans": [ + { + "bbox": [ + 308, + 325, + 542, + 426 + ], + "type": "table", + "html": "
MethodTo PKU-II
NTU-60NTU-120PKU-I
LongT GAN [62]44.8-43.6
MS²L [27]45.8-44.1
ISC [48]51.152.345.1
CMD [34]56.057.0-
SkeletonMAE* [53]58.461.062.5
MAMP (Ours)70.673.270.1
", + "image_path": "496793e953c4b0970ac242357e86949ff63e8a945f5c8d86c4bc54000802d1bf.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 429, + 547, + 462 + ], + "lines": [ + { + "bbox": [ + 305, + 429, + 547, + 462 + ], + "spans": [ + { + "bbox": [ + 305, + 429, + 547, + 462 + ], + "type": "text", + "content": "Table 6. Performance comparison on the PKU-II dataset under the transfer learning evaluation protocol. The source datasets are the NTU-60, NTU-120, and PKU-I datasets." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 483, + 547, + 593 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 483, + 547, + 593 + ], + "spans": [ + { + "bbox": [ + 304, + 483, + 547, + 593 + ], + "type": "text", + "content": "dataset. In this way, the generalizability of the learned representation is verified. In this paper, the target dataset is PKU-MMD II and the source datasets are NTU-60, NTU-120, and PKU-MMD I, respectively. Results in Table 6 show that, compared to previous methods, the representation learned by our proposed MAMP framework exhibits the best transferability, outperforming the reproduced SkeletonMAE* [53] by " + }, + { + "bbox": [ + 304, + 483, + 547, + 593 + ], + "type": "inline_equation", + "content": "12.2\\%" + }, + { + "bbox": [ + 304, + 483, + 547, + 593 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 483, + 547, + 593 + ], + "type": "inline_equation", + "content": "12.2\\%" + }, + { + "bbox": [ + 304, + 483, + 547, + 593 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 483, + 547, + 593 + ], + "type": "inline_equation", + "content": "7.6\\%" + }, + { + "bbox": [ + 304, + 483, + 547, + 593 + ], + "type": "text", + "content": " on the three source datasets, respectively." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 598, + 400, + 612 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 598, + 400, + 612 + ], + "spans": [ + { + "bbox": [ + 305, + 598, + 400, + 612 + ], + "type": "text", + "content": "4.4. Ablation Study" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 617, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 547, + 715 + ], + "type": "text", + "content": "Superiority of Masked Motion Prediction: As shown in Table 7, to verify the superiority of masked motion prediction, we designed four different ablative experiments. Given the joint and motion streams of the original data, all possible choices of the model input and reconstruction target are traversed. We can find that our joint-to-motion prediction significantly outperforms other strategies. Under the linear evaluation protocol, our MAMP exceeds joint-to-joint pre" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "10187" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 55, + 70, + 212, + 172 + ], + "blocks": [ + { + "bbox": [ + 55, + 70, + 212, + 172 + ], + "lines": [ + { + "bbox": [ + 55, + 70, + 212, + 172 + ], + "spans": [ + { + "bbox": [ + 55, + 70, + 212, + 172 + ], + "type": "image", + "image_path": "f784a4107d56e905adb406dbb19a072785564cca05a75b55cc3c85450cdc67ad.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 53, + 175, + 212, + 220 + ], + "lines": [ + { + "bbox": [ + 53, + 175, + 212, + 220 + ], + "spans": [ + { + "bbox": [ + 53, + 175, + 212, + 220 + ], + "type": "text", + "content": "Figure 3. Pre-training loss plot. Compared to masked self-reconstruction of joints in SkeletonMAE, masked motion prediction acts as a harder pre-training objective." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 218, + 70, + 376, + 173 + ], + "blocks": [ + { + "bbox": [ + 218, + 70, + 376, + 173 + ], + "lines": [ + { + "bbox": [ + 218, + 70, + 376, + 173 + ], + "spans": [ + { + "bbox": [ + 218, + 70, + 376, + 173 + ], + "type": "image", + "image_path": "a42f403a663c5865d71429e1234acfd34e57bb9b298836e962c8a6469be7a944.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 217, + 175, + 376, + 220 + ], + "lines": [ + { + "bbox": [ + 217, + 175, + 376, + 220 + ], + "spans": [ + { + "bbox": [ + 217, + 175, + 376, + 220 + ], + "type": "text", + "content": "Figure 4. Ablation study on the masking ratio. The performance is evaluated on the NTU-60 X-sub dataset under the linear evaluation protocol." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 383, + 69, + 541, + 172 + ], + "blocks": [ + { + "bbox": [ + 383, + 69, + 541, + 172 + ], + "lines": [ + { + "bbox": [ + 383, + 69, + 541, + 172 + ], + "spans": [ + { + "bbox": [ + 383, + 69, + 541, + 172 + ], + "type": "image", + "image_path": "d512013717936363dde230c01cda2c4bd4602f971711e4c28c904df9f9111b46.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 381, + 175, + 539, + 220 + ], + "lines": [ + { + "bbox": [ + 381, + 175, + 539, + 220 + ], + "spans": [ + { + "bbox": [ + 381, + 175, + 539, + 220 + ], + "type": "text", + "content": "Figure 5. Pre-training schedule of SkeletonMAE and our MAMP. The performance is evaluated on the NTU-60 X-sub dataset under the linear evaluation protocol." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 59, + 238, + 274, + 304 + ], + "blocks": [ + { + "bbox": [ + 59, + 238, + 274, + 304 + ], + "lines": [ + { + "bbox": [ + 59, + 238, + 274, + 304 + ], + "spans": [ + { + "bbox": [ + 59, + 238, + 274, + 304 + ], + "type": "table", + "html": "
InputTargetNTU-60NTU-120
JointJoint74.872.5
Motion84.978.6
MotionJoint76.571.0
Motion75.970.5
", + "image_path": "48b00ef1203e09c82d237d456ab57af8b2e8082390d21efdd52a92c34dc49956.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 58, + 350, + 274, + 392 + ], + "blocks": [ + { + "bbox": [ + 47, + 306, + 287, + 340 + ], + "lines": [ + { + "bbox": [ + 47, + 306, + 287, + 340 + ], + "spans": [ + { + "bbox": [ + 47, + 306, + 287, + 340 + ], + "type": "text", + "content": "Table 7. Ablation study on the superiority of masked motion prediction. The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 58, + 350, + 274, + 392 + ], + "lines": [ + { + "bbox": [ + 58, + 350, + 274, + 392 + ], + "spans": [ + { + "bbox": [ + 58, + 350, + 274, + 392 + ], + "type": "table", + "html": "
StrategyNTU-60NTU-120
Random masking83.777.3
Motion-aware masking84.978.6
", + "image_path": "1e273c1fd1a06494268cc3f70707bd8e0d4b7d100f5f25a6410a5fa545d510fb.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 449, + 287, + 496 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 449, + 287, + 496 + ], + "spans": [ + { + "bbox": [ + 47, + 449, + 287, + 496 + ], + "type": "text", + "content": "dition (adopted by [53]) by " + }, + { + "bbox": [ + 47, + 449, + 287, + 496 + ], + "type": "inline_equation", + "content": "10.1\\%" + }, + { + "bbox": [ + 47, + 449, + 287, + 496 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 449, + 287, + 496 + ], + "type": "inline_equation", + "content": "6.1\\%" + }, + { + "bbox": [ + 47, + 449, + 287, + 496 + ], + "type": "text", + "content": " on NTU-60 and NTU-120, respectively. This suggests that predicting dynamic motion from static skeletons during pre-training facilitates better contextual modeling of 3D human actions." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 497, + 287, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 497, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 47, + 497, + 287, + 533 + ], + "type": "text", + "content": "We also visualize the pre-training loss in Figure 3. Unlike the fast convergence of SkeletonMAE, masked motion prediction serves as a much harder pre-training objective." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 533, + 287, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 533, + 287, + 665 + ], + "spans": [ + { + "bbox": [ + 46, + 533, + 287, + 665 + ], + "type": "text", + "content": "Mask Sampling Strategy: In our approach, we employ the vanilla transformer as the backbone network, where embedding features at any spatio-temporal location can be freely masked as in MAE [17]. To verify the effectiveness of the proposed motion-aware masking strategy, we compare its performance with that of random masking in Table 8. As we can see, our motion-aware masking strategy brings absolute performance improvements of " + }, + { + "bbox": [ + 46, + 533, + 287, + 665 + ], + "type": "inline_equation", + "content": "1.2\\%" + }, + { + "bbox": [ + 46, + 533, + 287, + 665 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 533, + 287, + 665 + ], + "type": "inline_equation", + "content": "1.3\\%" + }, + { + "bbox": [ + 46, + 533, + 287, + 665 + ], + "type": "text", + "content": " on NTU-60 and NTU-120, respectively. This suggests that the motion information, as an empirical semantic richness prior, can effectively guide the skeleton masking process." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "content": "Segment Length: We evaluated the performance of the learned representation under different segment lengths " + }, + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "content": " used in the joint embedding process. For a fair comparison, we resize the original input sequence to ensure that the" + } + ] + } + ], + "index": 13 + }, + { + "type": "table", + "bbox": [ + 326, + 238, + 525, + 303 + ], + "blocks": [ + { + "bbox": [ + 47, + 393, + 287, + 427 + ], + "lines": [ + { + "bbox": [ + 47, + 393, + 287, + 427 + ], + "spans": [ + { + "bbox": [ + 47, + 393, + 287, + 427 + ], + "type": "text", + "content": "Table 8. Ablation study on the mask sampling strategy. The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 326, + 238, + 525, + 303 + ], + "lines": [ + { + "bbox": [ + 326, + 238, + 525, + 303 + ], + "spans": [ + { + "bbox": [ + 326, + 238, + 525, + 303 + ], + "type": "table", + "html": "
Te=Ts/lTslNTU-60NTU-120
3060284.677.8
120484.978.6
180683.378.6
240884.577.9
", + "image_path": "1d8e33d37b1dbe5b9a055f56a3d570d3355789846b680c2a860f882bc67a2aa0.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "table_body" + } + ], + "index": 14 + }, + { + "type": "table", + "bbox": [ + 313, + 371, + 420, + 437 + ], + "blocks": [ + { + "bbox": [ + 305, + 305, + 546, + 361 + ], + "lines": [ + { + "bbox": [ + 305, + 305, + 546, + 361 + ], + "spans": [ + { + "bbox": [ + 305, + 305, + 546, + 361 + ], + "type": "text", + "content": "Table 9. Ablation study on the segment length " + }, + { + "bbox": [ + 305, + 305, + 546, + 361 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 305, + 305, + 546, + 361 + ], + "type": "text", + "content": " used in the joint embedding process. For a fair comparison, the input length " + }, + { + "bbox": [ + 305, + 305, + 546, + 361 + ], + "type": "inline_equation", + "content": "T_{s}" + }, + { + "bbox": [ + 305, + 305, + 546, + 361 + ], + "type": "text", + "content": " is adjusted to ensure that the embedded features have a fixed length " + }, + { + "bbox": [ + 305, + 305, + 546, + 361 + ], + "type": "inline_equation", + "content": "T_{e}" + }, + { + "bbox": [ + 305, + 305, + 546, + 361 + ], + "type": "text", + "content": ". The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 313, + 371, + 420, + 437 + ], + "lines": [ + { + "bbox": [ + 313, + 371, + 420, + 437 + ], + "spans": [ + { + "bbox": [ + 313, + 371, + 420, + 437 + ], + "type": "table", + "html": "
LdNTU-60NTU-120
283.377.2
384.977.6
484.677.5
584.978.6
", + "image_path": "44826abffb091b5631362cd5fda6782ad1c3fd5e9c1a195fd1c8d40e3d4f122c.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "table_body" + } + ], + "index": 16 + }, + { + "type": "table", + "bbox": [ + 430, + 371, + 539, + 437 + ], + "blocks": [ + { + "bbox": [ + 331, + 441, + 400, + 452 + ], + "lines": [ + { + "bbox": [ + 331, + 441, + 400, + 452 + ], + "spans": [ + { + "bbox": [ + 331, + 441, + 400, + 452 + ], + "type": "text", + "content": "(a) Decoder depth." + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 430, + 371, + 539, + 437 + ], + "lines": [ + { + "bbox": [ + 430, + 371, + 539, + 437 + ], + "spans": [ + { + "bbox": [ + 430, + 371, + 539, + 437 + ], + "type": "table", + "html": "
CdNTU-60NTU-120
6482.374.2
12883.577.3
25684.978.6
51284.577.1
", + "image_path": "eb83eb619f7659901b3462c1c769cc08f403bbc5fd20ddfa84c095838c5883cd.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "table_body" + } + ], + "index": 18 + }, + { + "bbox": [ + 449, + 441, + 518, + 451 + ], + "lines": [ + { + "bbox": [ + 449, + 441, + 518, + 451 + ], + "spans": [ + { + "bbox": [ + 449, + 441, + 518, + 451 + ], + "type": "text", + "content": "(b) Decoder width." + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 305, + 455, + 545, + 489 + ], + "lines": [ + { + "bbox": [ + 305, + 455, + 545, + 489 + ], + "spans": [ + { + "bbox": [ + 305, + 455, + 545, + 489 + ], + "type": "text", + "content": "Table 10. Ablation study on the decoder design. The performance is evaluated on the NTU-60 X-sub and NTU-120 X-sub datasets under the linear evaluation protocol." + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 510, + 545, + 545 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 510, + 545, + 545 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 545, + 545 + ], + "type": "text", + "content": "embedded features have a fixed length " + }, + { + "bbox": [ + 304, + 510, + 545, + 545 + ], + "type": "inline_equation", + "content": "T_{e} = T_{s} / l = 30" + }, + { + "bbox": [ + 304, + 510, + 545, + 545 + ], + "type": "text", + "content": ". As shown in Table 9, a segment length of 4 brings the best performance on both NTU-60 and NTU-120 datasets." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 545, + 545, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 545, + 545, + 653 + ], + "spans": [ + { + "bbox": [ + 304, + 545, + 545, + 653 + ], + "type": "text", + "content": "Decoder Design: We experimented with different numbers of layers and widths (feature dimensions) for the transformer decoder. As shown in Table 10 (a), our MAMP exhibits the best performance on the NTU-60 and NTU-120 datasets when the number of decoder layers is 3 and 5, respectively. The experimental results of the decoder width are in Table 10 (b), where a width of 256 brings the best performance. Overall, a decoder with 5 layers and a width of 256 is adopted in our MAMP framework by default." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "Masking Ratio: As shown in Figure 4, we experimented with different masking ratios. Results on NTU-60 X-sub show that either too large or too small masking ratios have a negative impact on performance. We empirically found that a masking ratio of " + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "inline_equation", + "content": "90\\%" + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": " exhibits the best results." + } + ] + } + ], + "index": 23 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10188" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 169 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 169 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 169 + ], + "type": "text", + "content": "Pre-training Schedule: We studied the influence of the pre-training schedule length. As shown in Figure 5, both SkeletonMAE and our MAMP exhibit higher performance with longer pre-training schedules. It is worth mentioning that our MAMP significantly outperforms SkeletonMAE for all pre-training schedules with lengths ranging from 80 to 400 epochs, demonstrating the stability and superiority of the proposed masked motion prediction strategy." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 178, + 119, + 190 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 178, + 119, + 190 + ], + "spans": [ + { + "bbox": [ + 47, + 178, + 119, + 190 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 198, + 289, + 390 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 198, + 289, + 390 + ], + "spans": [ + { + "bbox": [ + 46, + 198, + 289, + 390 + ], + "type": "text", + "content": "In this work, we present MAMP, a simple yet effective framework for 3D action representation learning. We show that compared to conventional masked self-reconstruction of human joints, masked joint-to-motion prediction is demonstrated to be more effective for contextual motion modeling of 3D human actions. Given the high temporal redundancy of the skeleton sequence, we further devise the motion-aware masking strategy, which incorporates motion intensity as the empirical semantic richness prior for adaptive skeleton masking, facilitating better attention to semantically rich temporal regions. We conduct extensive experiments on three prevalent benchmarks under four evaluation protocols. Results show that the proposed MAMP brings remarkable performance improvements and sets a series of new state-of-the-art records, unleashing the tremendous potential of vanilla transformers for 3D action modeling." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 401, + 288, + 462 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 401, + 288, + 462 + ], + "spans": [ + { + "bbox": [ + 46, + 401, + 288, + 462 + ], + "type": "text", + "content": "Acknowledgement: This work was supported by NSFC under Contract U20A20183 & 61836011. It was also supported by the GPU cluster built by MCC Lab of Information Science and Technology Institution, USTC, and the Supercomputing Center of the USTC." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 471, + 106, + 483 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 471, + 106, + 483 + ], + "spans": [ + { + "bbox": [ + 48, + 471, + 106, + 483 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 491, + 288, + 714 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 53, + 491, + 287, + 525 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 491, + 287, + 525 + ], + "spans": [ + { + "bbox": [ + 53, + 491, + 287, + 525 + ], + "type": "text", + "content": "[1] Dana H Ballard. Modular learning in neural networks. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), volume 647, pages 279-284, 1987. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 525, + 288, + 568 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 525, + 288, + 568 + ], + "spans": [ + { + "bbox": [ + 53, + 525, + 288, + 568 + ], + "type": "text", + "content": "[2] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. BEiT: BERT pre-training of image transformers. In Proceedings of the International Conference on Learning Representations (ICLR), 2022. 3, 7" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 569, + 288, + 613 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 569, + 288, + 613 + ], + "spans": [ + { + "bbox": [ + 53, + 569, + 288, + 613 + ], + "type": "text", + "content": "[3] Z. Cao, G. Hidalgo, T. Simon, S. Wei, and Y. Sheikh. OpenPose: Realtime multi-person 2D pose estimation using part affinity fields. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 43(01):172-186, 2021. 1" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 614, + 288, + 669 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 614, + 288, + 669 + ], + "spans": [ + { + "bbox": [ + 53, + 614, + 288, + 669 + ], + "type": "text", + "content": "[4] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Proceedings of the European Conference on Computer Vision (ECCV), pages 213-229, 2020. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 670, + 288, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 670, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 53, + 670, + 288, + 714 + ], + "type": "text", + "content": "[5] Yuxin Chen, Ziqi Zhang, Chunfeng Yuan, Bing Li, Ying Deng, and Weiming Hu. Channel-wise topology refinement graph convolution for skeleton-based action recognition. In Proceedings of the IEEE/CVF International Conference on" + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 24, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 94 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 94 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 94 + ], + "type": "text", + "content": "Computer Vision (ICCV), pages 13359-13368, 2021. 1, 3, 6, 7" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 312, + 97, + 547, + 163 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 97, + 547, + 163 + ], + "spans": [ + { + "bbox": [ + 312, + 97, + 547, + 163 + ], + "type": "text", + "content": "[6] Yuxiao Chen, Long Zhao, Jianbo Yuan, Yu Tian, Zhaoyang Xia, Shijie Geng, Ligong Han, and Dimitris N Metaxas. Hierarchically self-supervised transformer for human skeleton representation learning. In Proceedings of the European Conference on Computer Vision (ECCV), pages 185-202, 2022. 6, 7" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 312, + 165, + 547, + 220 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 165, + 547, + 220 + ], + "spans": [ + { + "bbox": [ + 312, + 165, + 547, + 220 + ], + "type": "text", + "content": "[7] Ke Cheng, Yifan Zhang, Xiangyu He, Weihan Chen, Jian Cheng, and Hanqing Lu. Skeleton-based action recognition with shift graph convolutional network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 183-192, 2020. 1" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 312, + 222, + 547, + 255 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 222, + 547, + 255 + ], + "spans": [ + { + "bbox": [ + 312, + 222, + 547, + 255 + ], + "type": "text", + "content": "[8] Hyung-gun Chi et al. InfoGCN: Representation learning for human skeleton-based action recognition. In CVPR, 2022. 6, 7" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 312, + 256, + 547, + 300 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 256, + 547, + 300 + ], + "spans": [ + { + "bbox": [ + 312, + 256, + 547, + 300 + ], + "type": "text", + "content": "[9] Liu Chunhui, Hu Yueyu, Li Yanghao, Song Sijie, and Liu Jiaying. PKU-MMD: A large scale benchmark for continuous multi-modal human action understanding. arXiv preprint arXiv:1703.07475, 2017. 5" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 302, + 545, + 336 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 302, + 545, + 336 + ], + "spans": [ + { + "bbox": [ + 307, + 302, + 545, + 336 + ], + "type": "text", + "content": "[10] Kevin Clark, Minh-Thang Luong, Quoc V. Le, and Christopher D. Manning. ELECTRA: Pre-training text encoders as discriminators rather than generators. In ICLR, 2020. 7" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 338, + 545, + 405 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 338, + 545, + 405 + ], + "spans": [ + { + "bbox": [ + 307, + 338, + 545, + 405 + ], + "type": "text", + "content": "[11] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. BERT: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of the Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (NAACL-HLT), pages 4171–4186, 2019. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 406, + 545, + 483 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 406, + 545, + 483 + ], + "spans": [ + { + "bbox": [ + 308, + 406, + 545, + 483 + ], + "type": "text", + "content": "[12] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In Proceedings of the International Conference on Learning Representations (ICLR), 2021. 3, 5" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 484, + 545, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 484, + 545, + 529 + ], + "spans": [ + { + "bbox": [ + 308, + 484, + 545, + 529 + ], + "type": "text", + "content": "[13] Yong Du, Yun Fu, and Liang Wang. Skeleton based action recognition with convolutional neural network. In Proceedings of the Asian Conference on Pattern Recognition (ACPR), pages 579-583, 2015. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 531, + 545, + 586 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 531, + 545, + 586 + ], + "spans": [ + { + "bbox": [ + 308, + 531, + 545, + 586 + ], + "type": "text", + "content": "[14] Yong Du, Wei Wang, and Liang Wang. Hierarchical recurrent neural network for skeleton based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1110-1118, 2015. 1, 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 587, + 545, + 610 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 587, + 545, + 610 + ], + "spans": [ + { + "bbox": [ + 308, + 587, + 545, + 610 + ], + "type": "text", + "content": "[15] Haodong Duan et al. Revisiting skeleton-based action recognition. In CVPR, 2022. 6, 7" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 611, + 545, + 657 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 611, + 545, + 657 + ], + "spans": [ + { + "bbox": [ + 308, + 611, + 545, + 657 + ], + "type": "text", + "content": "[16] Hao-Shu Fang, Shuqin Xie, Yu-Wing Tai, and Cewu Lu. RMPE: Regional multi-person pose estimation. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 2334-2343, 2017. 1" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 658, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 658, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 658, + 545, + 713 + ], + "type": "text", + "content": "[17] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 16000-16009, 2022. 2, 3, 4, 5, 8" + } + ] + } + ], + "index": 23 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "10189" + } + ] + } + ], + "index": 25 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 714 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 117 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 117 + ], + "type": "text", + "content": "[18] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition (CVPR), pages 770-778, 2016. 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 118, + 288, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 118, + 288, + 173 + ], + "spans": [ + { + "bbox": [ + 48, + 118, + 288, + 173 + ], + "type": "text", + "content": "[19] Qiuhong Ke, Mohammed Bennamoun, Senjian An, Ferdous Sohel, and Farid Boussaid. A new representation of skeleton sequences for 3D action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 3288-3297, 2017. 1" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 175, + 288, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 175, + 288, + 228 + ], + "spans": [ + { + "bbox": [ + 48, + 175, + 288, + 228 + ], + "type": "text", + "content": "[20] Boeun Kim, Hyung Jin Chang, Jungho Kim, and Jin Young Choi. Global-local motion transformer for unsupervised skeleton-based action learning. In Proceedings of the European Conference on Computer Vision (ECCV), pages 209-225, 2022. 6" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 230, + 287, + 275 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 230, + 287, + 275 + ], + "spans": [ + { + "bbox": [ + 48, + 230, + 287, + 275 + ], + "type": "text", + "content": "[21] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E Hinton. Imagenet classification with deep convolutional neural networks. In Proceedings of the Advances in Neural Information Processing Systems (NeurIPS), 2012. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 276, + 287, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 276, + 287, + 330 + ], + "spans": [ + { + "bbox": [ + 48, + 276, + 287, + 330 + ], + "type": "text", + "content": "[22] Chao Li, Qiaoyong Zhong, Di Xie, and Shiliang Pu. Skeleton-based action recognition with convolutional neural networks. In Proceedings of the IEEE International Conference on Multimedia & Expo Workshops (ICMEW), pages 597-600. IEEE, 2017. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 332, + 287, + 397 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 332, + 287, + 397 + ], + "spans": [ + { + "bbox": [ + 48, + 332, + 287, + 397 + ], + "type": "text", + "content": "[23] Linguo Li, Minsi Wang, Bingbing Ni, Hang Wang, Jiancheng Yang, and Wenjun Zhang. 3D human action representation learning via cross-view consistency pursuit. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4741-4750, 2021. 2, 3, 6, 7" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 399, + 287, + 454 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 399, + 287, + 454 + ], + "spans": [ + { + "bbox": [ + 48, + 399, + 287, + 454 + ], + "type": "text", + "content": "[24] Maosen Li, Siheng Chen, Xu Chen, Ya Zhang, Yanfeng Wang, and Qi Tian. Actional-structural graph convolutional networks for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 3595–3603, 2019. 1" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 456, + 287, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 456, + 287, + 510 + ], + "spans": [ + { + "bbox": [ + 48, + 456, + 287, + 510 + ], + "type": "text", + "content": "[25] Tianjiao Li, Qiuhong Ke, Hossein Rahmani, Rui En Ho, Henghui Ding, and Jun Liu. Else-Net: Elastic semantic network for continual action recognition from skeleton data. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13434–13443, 2021. 1" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 512, + 287, + 578 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 512, + 287, + 578 + ], + "spans": [ + { + "bbox": [ + 48, + 512, + 287, + 578 + ], + "type": "text", + "content": "[26] Duohan Liang, Guoliang Fan, Guangfeng Lin, Wanjun Chen, Xiaorong Pan, and Hong Zhu. Three-stream convolutional neural network with multi-task and ensemble learning for 3D action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW), pages 934-940, 2019. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 579, + 287, + 633 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 579, + 287, + 633 + ], + "spans": [ + { + "bbox": [ + 48, + 579, + 287, + 633 + ], + "type": "text", + "content": "[27] Lilang Lin, Sijie Song, Wenhan Yang, and Jiaying Liu. MS2L: Multi-task self-supervised learning for skeleton based action recognition. In Proceedings of the 28th ACM International Conference on Multimedia (ACM MM), pages 2490-2498, 2020. 2, 3, 6, 7" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 635, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 635, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 635, + 287, + 689 + ], + "type": "text", + "content": "[28] Jun Liu, Amir Shahroudy, Mauricio Perez, Gang Wang, Ling-Yu Duan, and Alex C Kot. NTU RGB+D 120: A large-scale benchmark for 3D human activity understanding. IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI), 42(10):2684-2701, 2020. 2, 5" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "type": "text", + "content": "[29] Jun Liu, Amir Shahroudy, Dong Xu, Alex C Kot, and Gang Wang. Skeleton-based action recognition using spatio" + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 714 + ], + "type": "list", + "angle": 0, + "index": 27, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "type": "text", + "content": "temporal LSTM network with trust gates. IEEE transactions on pattern analysis and machine intelligence (TPAMI), 40(12):3007-3021, 2017. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 307, + 107, + 545, + 152 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 152 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 152 + ], + "type": "text", + "content": "[30] Jun Liu, Amir Shahroudy, Dong Xu, and Gang Wang. Spatio-temporal LSTM with trust gates for 3D human action recognition. In Proceedings of the European Conference on Computer Vision (ECCV), pages 816-833. Springer, 2016. 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 153, + 545, + 196 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 153, + 545, + 196 + ], + "spans": [ + { + "bbox": [ + 307, + 153, + 545, + 196 + ], + "type": "text", + "content": "[31] Xiao Liu, Fanjin Zhang, Zhenyu Hou, Li Mian, Zhaoyu Wang, Jing Zhang, and Jie Tang. Self-supervised learning: Generative or contrastive. IEEE Transactions on Knowledge and Data Engineering (TKDE), 35(1):857-876, 2023. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 198, + 545, + 252 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 198, + 545, + 252 + ], + "spans": [ + { + "bbox": [ + 307, + 198, + 545, + 252 + ], + "type": "text", + "content": "[32] Ziyu Liu, Hongwen Zhang, Zhenghao Chen, Zhiyong Wang, and Wanli Ouyang. Disentangling and unifying graph convolutions for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 143-152, 2020. 1, 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 254, + 545, + 286 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 254, + 545, + 286 + ], + "spans": [ + { + "bbox": [ + 307, + 254, + 545, + 286 + ], + "type": "text", + "content": "[33] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In Proceedings of the International Conference on Learning Representations (ICLR), 2019. 5" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 288, + 545, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 288, + 545, + 342 + ], + "spans": [ + { + "bbox": [ + 308, + 288, + 545, + 342 + ], + "type": "text", + "content": "[34] Yunyao Mao, Wengang Zhou, Zhenbo Lu, Jiajun Deng, and Houqiang Li. CMD: Self-supervised 3D action representation learning with cross-modal mutual distillation. In Proceedings of the European Conference on Computer Vision (ECCV), pages 734-752, 2022. 3, 6, 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 344, + 545, + 387 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 344, + 545, + 387 + ], + "spans": [ + { + "bbox": [ + 308, + 344, + 545, + 387 + ], + "type": "text", + "content": "[35] Chiara Plizzari, Marco Cannici, and Matteo Matteucci. Skeleton-based action recognition via spatial and temporal transformer networks. Computer Vision and Image Understanding, 208:103219, 2021. 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 388, + 545, + 421 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 388, + 545, + 421 + ], + "spans": [ + { + "bbox": [ + 308, + 388, + 545, + 421 + ], + "type": "text", + "content": "[36] Helei Qiu, Biao Hou, Bo Ren, and Xiaohua Zhang. Spatiotemporal tuples transformer for skeleton-based action recognition. arXiv preprint arXiv:2201.02849, 2022. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 422, + 545, + 466 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 422, + 545, + 466 + ], + "spans": [ + { + "bbox": [ + 308, + 422, + 545, + 466 + ], + "type": "text", + "content": "[37] Haocong Rao, Shihao Xu, Xiping Hu, Jun Cheng, and Bin Hu. Augmented skeleton based contrastive action learning with momentum LSTM for unsupervised action recognition. Information Sciences, 569:90-109, 2021. 6" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 468, + 545, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 468, + 545, + 521 + ], + "spans": [ + { + "bbox": [ + 308, + 468, + 545, + 521 + ], + "type": "text", + "content": "[38] Amir Shahroudy, Jun Liu, Tian-Tsong Ng, and Gang Wang. NTU RGB+D: A large scale dataset for 3D human activity analysis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1010-1019, 2016. 2, 5" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 523, + 545, + 578 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 523, + 545, + 578 + ], + "spans": [ + { + "bbox": [ + 308, + 523, + 545, + 578 + ], + "type": "text", + "content": "[39] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. Skeleton-based action recognition with directed graph neural networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 7912-7921, 2019. 1, 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 579, + 545, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 579, + 545, + 634 + ], + "spans": [ + { + "bbox": [ + 308, + 579, + 545, + 634 + ], + "type": "text", + "content": "[40] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. Two-stream adaptive graph convolutional networks for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 12026-12035, 2019. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 635, + 545, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 635, + 545, + 679 + ], + "spans": [ + { + "bbox": [ + 308, + 635, + 545, + 679 + ], + "type": "text", + "content": "[41] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. Decoupled spatial-temporal attention network for skeleton-based action-gesture recognition. In Proceedings of the Asian Conference on Computer Vision (ACCV), 2020. 3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 681, + 547, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 681, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 308, + 681, + 547, + 714 + ], + "type": "text", + "content": "[42] Lei Shi, Yifan Zhang, Jian Cheng, and Hanqing Lu. AdaSGN: Adapting joint number and model size for efficient skeleton-based action recognition. In Proceedings of" + } + ] + } + ], + "index": 26 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "10190" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 73, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 67, + 73, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 73, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 73, + 287, + 95 + ], + "type": "text", + "content": "the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13413-13422, 2021. 1" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 149 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 149 + ], + "type": "text", + "content": "[43] Chenyang Si, Wentao Chen, Wei Wang, Liang Wang, and Tieniu Tan. An attention enhanced graph convolutional LSTM network for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1227-1236, 2019. 1" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 151, + 287, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 151, + 287, + 205 + ], + "spans": [ + { + "bbox": [ + 48, + 151, + 287, + 205 + ], + "type": "text", + "content": "[44] Chenyang Si, Xuecheng Nie, Wei Wang, Liang Wang, Tieniu Tan, and Jiashi Feng. Adversarial self-supervised learning for semi-supervised 3D action recognition. In Proceedings of the European Conference on Computer Vision (ECCV), pages 35-51, 2020. 7" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 206, + 287, + 249 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 206, + 287, + 249 + ], + "spans": [ + { + "bbox": [ + 48, + 206, + 287, + 249 + ], + "type": "text", + "content": "[45] Yuxin Song, Min Yang, Wenhao Wu, Dongliang He, Fu Li, and Jingdong Wang. It takes two: Masked appearance-motion modeling for self-supervised video transformer pretraining. arXiv preprint arXiv:2210.05234, 2022. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 251, + 287, + 303 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 251, + 287, + 303 + ], + "spans": [ + { + "bbox": [ + 48, + 251, + 287, + 303 + ], + "type": "text", + "content": "[46] Kun Su, Xiulong Liu, and Eli Shlizerman. PREDICT & CLUSTER: Unsupervised skeleton based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 9631-9640, 2020. 2, 3, 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 305, + 287, + 358 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 305, + 287, + 358 + ], + "spans": [ + { + "bbox": [ + 48, + 305, + 287, + 358 + ], + "type": "text", + "content": "[47] Yukun Su, Guosheng Lin, and Qingyao Wu. Self-supervised 3D skeleton action representation learning with motion consistency and continuity. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13328-13338, October 2021. 6, 7" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 361, + 287, + 413 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 361, + 287, + 413 + ], + "spans": [ + { + "bbox": [ + 48, + 361, + 287, + 413 + ], + "type": "text", + "content": "[48] Fida Mohammad Thoker, Hazel Doughty, and Cees GM Snoek. Skeleton-contrastive 3D action representation learning. In Proceedings of the ACM International Conference on Multimedia (ACM MM), pages 1655–1663, 2021. 2, 3, 5, 6, 7" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 415, + 287, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 415, + 287, + 470 + ], + "spans": [ + { + "bbox": [ + 48, + 415, + 287, + 470 + ], + "type": "text", + "content": "[49] Guo Tianyu, Liu Hong, Chen Zhan, Liu Mengyuan, Wang Tao, and Ding Runwei. Contrastive learning from extremely augmented skeleton sequences for self-supervised action recognition. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), 2022. 2, 3, 6, 7" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 471, + 287, + 536 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 471, + 287, + 536 + ], + "spans": [ + { + "bbox": [ + 48, + 471, + 287, + 536 + ], + "type": "text", + "content": "[50] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Herve Jegou. Training data-efficient image transformers & distillation through attention. In Proceedings of the International Conference on Machine Learning (ICML), volume 139, pages 10347-10357, July 2021. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 537, + 287, + 591 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 537, + 287, + 591 + ], + "spans": [ + { + "bbox": [ + 48, + 537, + 287, + 591 + ], + "type": "text", + "content": "[51] Hongsong Wang and Liang Wang. Modeling temporal dynamics and spatial configurations of actions using two-stream recurrent neural networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition (CVPR), pages 499-508, 2017. 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 593, + 287, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 593, + 287, + 646 + ], + "spans": [ + { + "bbox": [ + 48, + 593, + 287, + 646 + ], + "type": "text", + "content": "[52] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 14668-14678, 2022. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 647, + 287, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 287, + 690 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 287, + 690 + ], + "type": "text", + "content": "[53] Wenhan Wu, Yilei Hua, Ce zheng, Shiqian Wu, Chen Chen, and Aidong Lu. SkeletonMAE: Spatial-temporal masked autoencoders for self-supervised skeleton action recognition. arXiv preprint arXiv:2209.02399, 2022. 1, 3, 4, 6, 7, 8" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 692, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 692, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 692, + 287, + 713 + ], + "type": "text", + "content": "[54] Jingwei Xu, Zhenbo Yu, Bingbing Ni, Jiancheng Yang, Xiaokang Yang, and Wenjun Zhang. Deep kinematics analysis" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 546, + 562 + ], + "type": "list", + "angle": 0, + "index": 23, + "blocks": [ + { + "bbox": [ + 327, + 73, + 546, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 546, + 106 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 546, + 106 + ], + "type": "text", + "content": "for monocular 3D human pose estimation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 899-908, 2020. 1" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 308, + 107, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 107, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 308, + 107, + 545, + 150 + ], + "type": "text", + "content": "[55] Sijie Yan, Yuanjun Xiong, and Dahua Lin. Spatial temporal graph convolutional networks for skeleton-based action recognition. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), pages 7444-7452, 2018. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 152, + 545, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 152, + 545, + 205 + ], + "spans": [ + { + "bbox": [ + 308, + 152, + 545, + 205 + ], + "type": "text", + "content": "[56] Di Yang, Yaohui Wang, Antitza Dantcheva, Lorenzo Garattoni, Gianpiero Francesca, and Francois Bremond. ViA: View-invariant skeleton action representation learning via motion retargeting. arXiv preprint arXiv:2209.00065, 2022.6,7" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 208, + 545, + 261 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 208, + 545, + 261 + ], + "spans": [ + { + "bbox": [ + 308, + 208, + 545, + 261 + ], + "type": "text", + "content": "[57] Haosen Yang, Deng Huang, Bin Wen, Jiannan Wu, Hongxun Yao, Yi Jiang, Xiatian Zhu, and Zehuan Yuan. Self-supervised video representation learning with motion-aware masked autoencoders. arXiv preprint arXiv:2210.04154, 2022.3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 263, + 545, + 317 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 263, + 545, + 317 + ], + "spans": [ + { + "bbox": [ + 308, + 263, + 545, + 317 + ], + "type": "text", + "content": "[58] Siyuan Yang, Jun Liu, Shijian Lu, Meng Hwa Er, and Alex C Kot. Skeleton cloud colorization for unsupervised 3D action representation learning. In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV), pages 13423-13433, 2021. 2, 3, 6, 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 319, + 545, + 373 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 319, + 545, + 373 + ], + "spans": [ + { + "bbox": [ + 308, + 319, + 545, + 373 + ], + "type": "text", + "content": "[59] Haoyuan Zhang, Yonghong Hou, Wenjing Zhang, and Wanqing Li. Contrastive positive mining for unsupervised 3D action representation learning. In Proceedings of the European Conference on Computer Vision (ECCV), pages 36-51, 2022. 3, 6, 7" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 375, + 545, + 439 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 375, + 545, + 439 + ], + "spans": [ + { + "bbox": [ + 308, + 375, + 545, + 439 + ], + "type": "text", + "content": "[60] Pengfei Zhang, Cuiling Lan, Wenjun Zeng, Junliang Xing, Jianru Xue, and Nanning Zheng. Semantics-guided neural networks for efficient skeleton-based human action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 1112-1121, 2020. 1" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 441, + 545, + 495 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 441, + 545, + 495 + ], + "spans": [ + { + "bbox": [ + 308, + 441, + 545, + 495 + ], + "type": "text", + "content": "[61] Xikun Zhang, Chang Xu, and Dacheng Tao. Context aware graph convolution for skeleton-based action recognition. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 14333–14342, 2020. 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 498, + 545, + 562 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 498, + 545, + 562 + ], + "spans": [ + { + "bbox": [ + 308, + 498, + 545, + 562 + ], + "type": "text", + "content": "[62] Nenggan Zheng, Jun Wen, Risheng Liu, Liangqu Long, Jianhua Dai, and Zhefeng Gong. Unsupervised representation learning with long-term dynamics for skeleton based action recognition. In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI), pages 2644-2651, 2018. 2, 3, 4, 6, 7" + } + ] + } + ], + "index": 22 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10191" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/5a41b22e-9755-4ada-9123-4e6d5ca57c32_content_list.json b/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/5a41b22e-9755-4ada-9123-4e6d5ca57c32_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..7be034221287a7adfa30393c4dec28e43e8bad68 --- /dev/null +++ b/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/5a41b22e-9755-4ada-9123-4e6d5ca57c32_content_list.json @@ -0,0 +1,1636 @@ +[ + { + "type": "text", + "text": "Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection", + "text_level": 1, + "bbox": [ + 220, + 130, + 750, + 175 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Zijing Zhao $^{1}$ Sitong Wei $^{1}$ Qingchao Chen $^{2}$ Dehui Li $^{3}$ Yifan Yang $^{3}$ Yuxin Peng $^{1}$ Yang Liu $^{1*}$ $^{1}$ Wangxuan Institute of Computer Technology, Peking University \n $^{2}$ National Institute of Health Data Science, Peking University \n $^{3}$ Tencent Intelligent Mobility \nzijingzhao@stu.pku.edu.cn {weisitong, qingchao.chen, pengyuxin, yangliu}@oku.edu.cn \n{dehuili, lvanyang}@tencent.com", + "bbox": [ + 84, + 200, + 893, + 292 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 325, + 313, + 343 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Domain adaptive Object Detection (DAOD) leverages a labeled domain (source) to learn an object detector generalizing to a novel domain without annotation (target). Recent advances use a teacher-student framework, i.e., a student model is supervised by the pseudo labels from a teacher model. Though great success, they suffer from the limited number of pseudo boxes with incorrect predictions caused by the domain shift, misleading the student model to get sub-optimal results. To mitigate this problem, we propose Masked Retraining Teacher-student framework (MRT) which leverages masked autoencoder and selective retraining mechanism on detection transformer. Specifically, we present a customized design of masked autoencoder branch, masking the multi-scale feature maps of target images and reconstructing features by the encoder of the student model and an auxiliary decoder. This helps the student model capture target domain characteristics and become a more data-efficient learner to gain knowledge from the limited number of pseudo boxes. Furthermore, we adopt selective retraining mechanism, periodically re-initializing certain parts of the student parameters with masked autoencoder refined weights to allow the model to jump out of the local optimum biased to the incorrect pseudo labels. Experimental results on three DAOD benchmarks demonstrate the effectiveness of our method. Code can be found at https://github.com/JeremyZhao1998/MRT-release.", + "bbox": [ + 76, + 358, + 473, + 750 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 777, + 209, + 794 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Object detection has a wide range of real-world application scenarios, and has been deeply studied in computer vision researches. CNN-based [35, 32, 40] and transformer-based [3, 51] detectors have shown great success in challenging benchmarks. However, they suffer from domain", + "bbox": [ + 75, + 803, + 468, + 878 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/c6b35c3c697150246b1e1eb509c76f1920244abde7a71cf8db2ff3f1b30ea2f3.jpg", + "image_caption": [ + "(a) mAP under limited boxes", + "Figure 1. (a) Performance under limited number of box annotations. We adopt MAE in training target images with ground truth labels, but manually reduce the amount of bounding boxes. MAE boosts the performance by a large margin under limited boxes. (b) Performance of Category \"bicycle\" during training. The performance declines rapidly due to the local optimum caused by incorrect pseudo boxes. With the help of retraining (every 40 epochs), the model is able to jump out of the local optimum." + ], + "image_footnote": [], + "bbox": [ + 506, + 330, + 705, + 464 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/94cc22a39ad05ec3161251866f1c032ea8da4c01ee079e011ad09499cebe3164.jpg", + "image_caption": [ + "(b) Category AP during training" + ], + "image_footnote": [], + "bbox": [ + 707, + 330, + 885, + 464 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "shift where there is an obvious distribution gap between the pretraining data and the deployed environment.", + "bbox": [ + 496, + 638, + 890, + 670 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "To mitigate the performance drop caused by domain shift without extra annotation, unsupervised domain adaptation (UDA) has been studied in classification, segmentation and object detection tasks, where the model is trained on a labeled source domain and an unlabeled target domain, and is expected to generalize well on the target domain. As a branch of UDA, unsupervised domain adaptive object detection (DAOD) researches [9, 49, 29, 48] utilize numerous techniques such as adversarial alignment, image-to-image translation, GNNs and mean teacher training, widely improving domain adaptation performance of object detectors.", + "bbox": [ + 496, + 671, + 892, + 838 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Among these approaches, [29, 48, 5, 20] use a teacher-student framework where a teacher model produces pseudo labels of the unlabeled target images to supervise a student model, and has achieved significant performance gains.", + "bbox": [ + 496, + 839, + 893, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding author", + "bbox": [ + 94, + 887, + 220, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "19039", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "However, the teaching process faces the challenge of low-quality pseudo labels in which there are limited number of pseudo boxes and incorrect predictions caused by the domain shift. Under such framework, pseudo labels are selected from outputs of the teacher model by a threshold of confidence scores. Selecting large amounts of pseudo labels with lower threshold brings too many incorrect predictions, degrading the performance, while with higher threshold, the limited number of pseudo boxes provides sub-optimal supervision. Blue bars of Figure 1(a) shows that even supervised by ground truth labels without domain shift, the performance drops significantly when the amount of box annotations are reduced. Anyhow, incorrect predictions always exist, leading the model to get stuck at the local optimum. As is shown in Figure 1(b), in the later stage of training, performance of some categories declines rapidly (the blue curve) due to the growing number of incorrect pseudo boxes. Though [29] utilizes adversarial alignment and weak-strong augmentation to minimize the false positive ratio of pseudo labels, they ignore the sub-optimal supervision of the limited number of pseudo boxes, and the impact of incorrect pseudo labels which always exist.", + "bbox": [ + 76, + 90, + 472, + 422 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To address this issue, we propose Masked Retraining Teacher-student framework (MRT) which is built on the baseline of adaptive teacher-student framework for Deformable DETR[51] detector, leveraging masked autoencoder (MAE) and selective retraining mechanism.", + "bbox": [ + 76, + 425, + 470, + 501 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Unlike pretraining MAEs[19, 41] which leverage large-scale training data under a pretrain-finetune paradigm, we present a customized design of MAE branch, randomly masking portions of multi-scale feature maps of the target images and reconstructing the missing features from their contexts by the encoder of the student model and an auxiliary decoder, simultaneously with the detection loss. As a self-supervised task on target images, MAE leads the transformer encoder to gain more intimate knowledge of the target domain from the limited number of pseudo boxes. Empirically, we observe that MAE helps the model encode better features, improving the performance under any amount of supervision and achieving larger gains when fewer box annotations are provided, as is shown in Figure 1(a).", + "bbox": [ + 76, + 505, + 472, + 717 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Furthermore, as the student model is sensitive to the pseudo label noise, we adopt a simple yet effective selective retraining mechanism. Specifically, we periodically re-initialize certain parts of the student parameters to allow the model to jump out of the local optimum biased to the incorrect pseudo labels. Unlike existing retraining approaches [18, 34] that ignore the quality of re-initialization weights, we re-initialize the student model with MAE refined weights to avoid low-quality student weights to impact the teacher model through EMA. In teacher-student framework, an enhanced teacher model helps the student recover rapidly after the re-initialization. As is shown in the orange", + "bbox": [ + 76, + 719, + 472, + 902 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "curve of Figure 1(b), retraining recovers the performance that has been corrupted by noisy pseudo labels.", + "bbox": [ + 496, + 90, + 890, + 119 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We summarize the contribution of this paper as follow: 1) We propose a novel Masked Retraining Teacher-student framework(MRT) for training domain adaptive detection transformers, which is built on the adaptive teacher-student framework baseline and overcomes the problem of low-quality pseudo labels. 2) To the best of our knowledge, we are the first to present that masked autoencoder is a data-efficient domain adapter which helps the model better capture domain characteristics, and the first to adopt selective retraining mechanism in teacher-student framework to help the model jump out of local optimums. 3) Our method outperforms existing approaches by a large margin and achieves state-of-the-art on three DAOD benchmarks.", + "bbox": [ + 496, + 121, + 893, + 318 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 330, + 640, + 347 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Object detection: Object detection has been deeply studied in computer vision. CNN-based methods[35, 30, 31] present region proposals networks and achieve outstanding performance. One-stage detectors without region proposals [32, 40] simplify the structure and perform faster. Recently, transformer-based models [3, 51] are also developed in object detection, exploring token-wise dependencies for context modeling. These methods all focus on supervised learning, while we aim to generalize the model to a novel domain without extra annotations. In this work, we employ Deformable DETR[51] as the detector due to its simplified one-stage structure and the flexible transfer-learning ability of the transformer architecture.", + "bbox": [ + 496, + 357, + 893, + 551 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Domain adaptive object detection: Domain adaptive object detection (DAOD) is raised to overcome the domain shift problem in object detection. As a pioneer work of DAOD, [9] investigates adversarial feature alignment for Faster R-CNN. Following [9], [21, 8, 27, 7, 4, 36, 46] apply different aspects of feature alignments, and [44, 24, 17] elaborately design alignments for transformer architectures. Numerous techniques such as image-to-image translation[49], graph reasoning[28, 48] and pseudo label self-training[12, 29, 48] have also been studied for DAOD. Among existing approaches, methods utilizing teacher-student framework achieve leading position in experimental performances. [29] utilizes adversarial alignment and weak-strong augmentation to minimize the false positive ratio of pseudo labels. [20] reduces domain shift by incorporating target object knowledge through self-distillation. [5] employs uncertainty-guided self-training to promote both classification and localization adaptations. Though great success, they ignore the low-quality pseudo labels which contains limited number of bounding boxes and incorrect predictions. We build our method on the baseline of teacher-student framework with adversarial alignment, introducing MAE and selective retraining to overcome such problem.", + "bbox": [ + 496, + 553, + 893, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "19040", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Masked autoencoders: Autoencoding is a classical representation learning method, utilizing an encoder to map the input to a latent representation and a decoder to reconstruct the input. Denoising autoencoders (DAE)[42] corrupt the input signal and learn to reconstruct the original, uncorrupted signal. Recently, DAE methods are widely used in large-scale pretraining tasks in both language models [13, 2] and vision models [6, 14, 1], holding out a portion of the input and train models to predict the missing content. The influential MAE[19] randomly masks image patches with a high portion and reconstruct the missing pixels by an asymmetric architecture to pretrain a vision transformer that generalize well in downstream tasks. [41] explores MAE in video pretraining, raising the point that MAE is a data-efficient learner and domain shift is an important factor during pretraining. [11] employs attention mask for DETR decoder as an unsupervised pretraining task. However, these works all focus on pretraining transformer-based backbones with all accessible data to generalize to downstream tasks, without considering domain shift. We empirically observe that feeding MAE with inputs from mismatched domain provides sub-optimal results. Thus, we apply MAE only on target images for domain adaptation, guiding the encoder to better capture target domain characteristics.", + "bbox": [ + 76, + 90, + 472, + 454 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Overcoming local optimums: Optimizing neural networks faces the challenge of local optimums. Regularization methods such as Dropout[38] and DropBlock[16] try to avoid the model from over-fitting or getting trapped in local minimums by introducing randomness. [23] introduces cyclic learning rate, but is inapplicable for transformer-based models. Recent studies show that retraining is a simple yet effective way for transformers. [18] proposes DSD retraining with reference to model pruning to avoid overfitting to noisy data, and [34] proposes selective retraining mechanism for visual grounding transformers to converge to better minimums. To the best of our knowledge, we are the first to adopt retraining in teacher-student framework to overcome the impact of incorrect pseudo labels. Under such framework, quality of the re-initialization weights become significant, which has not been studied in existing retraining approaches, since the teacher model may be influenced by the re-initialized student weights to provide sub-optimal pseudo labels. We re-initializing the student parameters with MAE refined weights to avoid the problem.", + "bbox": [ + 76, + 454, + 472, + 758 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Problem Formulation and Baseline", + "text_level": 1, + "bbox": [ + 76, + 773, + 395, + 789 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Problem Formulation", + "text_level": 1, + "bbox": [ + 76, + 799, + 279, + 814 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We first review the problem formulation of unsupervised DAOD. Given a labeled source dataset $D_{s} = \\{(x_{s}^{i},y_{s}^{i})\\}_{i = 1}^{N_{s}}$ sized $N_{s}$ and an unlabeled target dataset $D_{t} = \\{x_{t}^{i}\\}_{i = 1}^{N_{t}}$ sized $N_{t}$ , where $x$ denotes an image and $y = (b,c)$ represents an annotation for object detection including bounding", + "bbox": [ + 76, + 823, + 468, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "box $b$ and the corresponding category $c$ , we train a domain adaptive detector with both $D_{s}$ and $D_{t}$ , and evaluate the detection performance on data in the target domain.", + "bbox": [ + 496, + 90, + 890, + 137 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Adaptive Teacher-student Baseline Revisited", + "text_level": 1, + "bbox": [ + 498, + 145, + 877, + 161 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Recent advances [46, 48] use a teacher-student framework combined with adversarial alignment and achieve SOTA. Our method is built on the adaptive teacher-student framework as baseline. We revisit the baseline as follow.", + "bbox": [ + 496, + 167, + 890, + 227 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Teacher-student framework: A teacher model $T$ and a student model $S$ share the same structure of backbone, encoder and decoder. The teacher takes a weakly augmented target image $x_{t}$ and produces pseudo labels $(\\hat{b}_{t},\\hat{c}_{t})$ . The student takes both source and target images which are strongly augmented. Supervised loss $\\mathcal{L}_{sup}$ is calculated on $x_{s}$ with their ground truth labels same as [51]:", + "bbox": [ + 496, + 229, + 890, + 335 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {s u p} = \\mathcal {L} _ {b o x} ^ {S} \\left(x _ {s}, y _ {s}\\right) + \\mathcal {L} _ {g i o u} ^ {S} \\left(x _ {s}, y _ {s}\\right) + \\mathcal {L} _ {c l s} ^ {S} \\left(x _ {s}, y _ {s}\\right) \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 509, + 343, + 890, + 362 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "while $x_{t}$ receive supervision from pseudo labels, but only in classification task following [46] as unsupervised loss:", + "bbox": [ + 496, + 371, + 890, + 402 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {u n s u p} = \\mathcal {L} _ {c l s} ^ {S} \\left(x _ {t}, \\hat {b} _ {t}, \\hat {c} _ {t}\\right) \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 609, + 410, + 890, + 429 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The teacher is only updated by Exponential Moving Average (EMA) from the student without gradient accumulation:", + "bbox": [ + 496, + 438, + 890, + 469 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\theta_ {t} \\leftarrow \\alpha \\theta_ {t} + (1 - \\alpha) \\theta_ {s} \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 617, + 483, + 890, + 500 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\theta_{t}$ and $\\theta_{s}$ denotes the model parameters of teacher and student respectively, and $\\alpha$ is a hyper-parameter.", + "bbox": [ + 496, + 505, + 890, + 535 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Discriminators for adversarial alignment: Domain discriminators $D$ are placed after certain components to predict the domain label of the features, updated by BCE loss. On Deformable DETR detector, we set discriminators for the backbone, encoder and decoder to provide global level, token-wise multi-scale feature level and instance level alignment respectively, and $\\mathcal{L}_{dis}$ denotes their weighted sum. The adversarial optimization objective is formulated:", + "bbox": [ + 496, + 536, + 890, + 656 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {a d v} = \\max _ {S} \\min _ {D} \\mathcal {L} _ {d i s} \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 620, + 667, + 890, + 689 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $S, D$ denotes the student and discriminators respectively. Gradient Reverse Layers(GRL)[15] is adopted for min-max optimization. Overall objective of the student is:", + "bbox": [ + 496, + 696, + 890, + 743 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {t e a c h}} = \\mathcal {L} _ {\\sup } + \\mathcal {L} _ {\\operatorname {a d v}} + \\lambda_ {\\text {u n s u p}} \\mathcal {L} _ {\\text {u n s u p}} \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 560, + 753, + 890, + 770 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\lambda_{unsup}$ is the hyper-parameter, while the teacher is updated only by EMA which has been discussed. Before teaching process, the model will first be trained with $\\mathcal{L}_{sup}$ using annotated source data $D_{s}$ , and both teacher and student model will be initialized with such parameters.", + "bbox": [ + 496, + 780, + 890, + 854 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The adaptive teacher-student baseline on Deformable DETR outperforms most existing DAOD approaches. However, the problem of low-quality pseudo labels still exist,", + "bbox": [ + 496, + 854, + 890, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "19041", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/ba04201101bba07153fef6bdb30cb84382b1023b51669b6386ed3025fd9c9fea.jpg", + "image_caption": [ + "Figure 2. Overview Masked Retraining Teacher-student framework(MRT). The adaptive teacher-student baseline consists of a teacher model which takes weakly-augmented target images and produces pseudo labels, and a student model which takes strongly augmented source and target images, supervised by ground truth labels and pseudo labels respectively. Adversarial alignment are applied on backbone, encoder and decoder. Our proposed MAE branch masks feature maps of target images, and and reconstructs the feature by student encoder and an auxiliary decoder. Our proposed selective retraining mechanism periodically re-initialize certain parts of the student parameters as highlighted. The teacher model is updated only by EMA from the student model. Empirically, we use the teacher model at inference time." + ], + "image_footnote": [], + "bbox": [ + 109, + 90, + 880, + 367 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "leading the model to sub-optimal results, as has been shown in Figure 1. Our proposed method overcomes this issue by introducing MAE branch and selective retraining mechanism which will be elaborated in the following section.", + "bbox": [ + 75, + 479, + 470, + 542 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. Proposed Method", + "text_level": 1, + "bbox": [ + 76, + 560, + 250, + 578 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Method Overview", + "text_level": 1, + "bbox": [ + 76, + 588, + 250, + 603 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Our proposed method can be overviewed in Figure 2, which is built on the adaptive teacher-student baseline discussed in Section 3.2. We propose a customized design of masked autoencoder(MAE) branch for student model, randomly masking a portion of the multi-scale feature maps of the target images, feeding them into the encoder, and introducing an auxiliary decoder to reconstruct the missing features from their contexts. As a self-supervised task on target images, MAE leads the transformer encoder to gain more intimate knowledge of the target domain, thus helps the model better capture target domain characteristics and boosts the performance when the amount of pseudo boxes are limited. Employing selective retraining mechanism, we periodically re-initialize parts of the student parameters with the MAE refined weights, as is illustrated in Figure 2 with marked units, while the teacher model is continually updated via exponential moving average (EMA) from the student model. In this way, the teacher model continually produces relatively high-quality pseudo labels without be", + "bbox": [ + 75, + 613, + 472, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "ing corrupted by re-initialized low-quality student weights, and the student model is allowed to jump out of the local optimum biased to the incorrect pseudo boxes. Selecting pseudo labels from outputs of the teacher is also important. A fixed confidence threshold is often used, but is unaware of the imbalance sample class distribution and the training period. We propose a dynamic threshold strategy to set different thresholds for each category dynamically during training, selecting appropriate amount of pseudo boxes.", + "bbox": [ + 496, + 479, + 890, + 618 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.2. Masked Autoencoder Branch", + "text_level": 1, + "bbox": [ + 498, + 631, + 759, + 647 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We propose a customized design of MAE branch for the student model to better capture target domain characteristic as a self-supervised domain adapter, and to effectively gain knowledge from the limited number of high-quality pseudo boxes. The multi-scale feature maps of target images will be masked and fed into the student encoder, and reconstructed by an auxiliary decoder. The masking and reconstructing processes are elaborated as follows.", + "bbox": [ + 496, + 656, + 890, + 777 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Feature masking: Unlike ViT [14] backbone which directly takes image patches as the input, the Deformable DETR encoder takes the multi-scale feature maps $\\{z_{i}\\in$ $\\mathbb{R}^{C_i\\times H_i\\times W_i}\\}_{i = 1}^K$ which are projected from the output of the backbone, where $K$ denotes the number of scales. We randomly generate masking $\\{m_i\\in \\{0,1\\}^{H_i\\times W_i}\\}_{i = 1}^K$ for every scale of the feature maps with the same masking ratio. The deformable attention relies on the spatial structure of the", + "bbox": [ + 496, + 779, + 892, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "19042", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "feature maps to generate reference points and sampling locations that is used to choose points on the value matrix to perform sparse attention, so the spatial structure of the input cannot be serialized. As a result, we set the masked portion of the corresponding value matrix to zero in deformable attention to perform zero-masking, unlike [19] that only sends unmasked patches as a serialized input to ViT.", + "bbox": [ + 75, + 90, + 468, + 196 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Reconstruction: The encoder takes the masked feature maps, and further encodes the feature maps with deformable attention. On the output features of the encoder, we fill the masked portion with a shared mask query $q_{m}$ and send them to an auxiliary MAE decoder $S_{m}$ to reconstruct the feature map. Following [19], we adopt an asymmetric lightweight decoder. Since the last layer of the backbone outputs, i.e., $z_{K}$ contains all the semantic information, we only reconstruct it to speed up convergence and reduce computation. The last layer of MAE decoder is a linear projection whose output channels equals to the channels of $z_{K}$ . Eventually, we compute mean square error (MSE) between the reconstructed and original features, but only on the masked portion, formulated as:", + "bbox": [ + 75, + 196, + 470, + 407 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {z} _ {K} = S _ {m} \\left(S _ {e} \\left(\\operatorname {m a s k} \\left(m, x _ {t}\\right)\\right), q _ {m}\\right) \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 158, + 414, + 468, + 430 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {m a s k}} = \\mathcal {L} _ {\\text {M S E}} \\left(\\operatorname {m a s k} \\left(m _ {K}, z _ {K} ^ {\\prime}\\right), \\operatorname {m a s k} \\left(m _ {K}, z _ {K}\\right)\\right) \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 89, + 434, + 468, + 450 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $S_{e}, S_{m}, q_{m}$ denotes the encoder of student model, the auxiliary MAE decoder and the mask query respectively.", + "bbox": [ + 76, + 455, + 468, + 484 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Training data: Note that although student model takes both source and target images, we employ MAE only on target images, since DAOD aims to train the detector to perform better on the unlabeled target domain, and applying MAE with source images leads the model to generate source domain features with sub-optimal performance. Employing MAE on target images helps the student encoder to gain more intimate knowledge of the target domain, and boosts performance when high-quality pseudo labels are limited. We apply MAE on student model instead of teacher, for it is the student model who suffers from sub-optimal supervision of the limited pseudo boxes. Besides, the teacher model is not supervised by any detection loss. Employing MAE on the teacher model creates an encoder that is incompatible with the decoder and detection head, thus is unable to provide meaningful pseudo labels.", + "bbox": [ + 75, + 486, + 468, + 727 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Training strategy: We train the MAE branch and detection loss simultaneously instead of following the pretrainfinetune paradigm, since pretraining leads the model to over-fit to reconstruction task due to the relatively small dataset with distinctive domain characteristics. Before the teaching process, we first train the model with $\\mathcal{L}_{sup}$ in Equation(1) together with $\\mathcal{L}_{mask}$ in Equation(7) to produce an enhanced initialization $\\theta_{mask}$ for teaching, and as a refined re-initialization for selective retraining. The overall objective of student model in teaching process is:", + "bbox": [ + 75, + 727, + 468, + 878 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} = \\mathcal {L} _ {\\text {t e a c h}} + \\lambda_ {\\text {m a s k}} \\mathcal {L} _ {\\text {m a s k}} \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 179, + 885, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathcal{L}_{\\text {teach }}$ has been formulated in Equation(5), and $\\lambda_{mask}$ is the coefficient of $\\mathcal{L}_{mask}$ in Equation(7). As the teaching process continues, adequate amount of pseudo boxes will be produced, and the influence of $\\mathcal{L}_{mask}$ should be lowered to avoid the encoder over-fitting to reconstruction task. As a result, We decay $\\lambda_{mask}$ as teaching continues. More details will be discussed in Section 5.4.", + "bbox": [ + 498, + 90, + 890, + 196 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.3. Selective Retraining Mechanism", + "text_level": 1, + "bbox": [ + 500, + 207, + 782, + 223 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The transformer-based models tend to over-fit without large-scale training data, especially when noisy annotations are included. Here in our case, pseudo labels always contain noise since they are provided by the updating teacher model instead of ground truths. As is shown in Figure 1(b), in later stage of the teaching process, performance of certain categories are severely influenced due to the over-fitting to the incorrect pseudo labels. Worse still, since the teacher model is continually updated via EMA from student model, it could also by affected and produces even worse pseudo labels. We adopt selective retraining mechanism on student branch to help student model jump out of local optimums biased to incorrect pseudo labels.", + "bbox": [ + 496, + 231, + 890, + 426 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To be specific, during teaching period, we continually update the teacher model via EMA without retraining it, but periodically re-initialize parts of the student model with the MAE refined parameters $\\theta_{mask}$ which has been discussed in Section 4.2. Though $\\theta_{mask}$ do not contain detection knowledge, its target domain encoding ability has not been corrupted by noisy pseudo labels. After re-initialization, the retrained components are allowed to leave the local optimum and can be guided by the fixed parts which can be regarded as better trained, and by an enhanced teacher which is continually updated. We do not retrain the teacher model since re-initialization cause a sudden drop of pseudo label quality, thus deteriorate the teaching process. We re-initialize the student model with MAE refined weights $\\theta_{mask}$ rather than source-only trained weights or random weights for a quicker recovery, preventing its negative influence to teacher via EMA. We choose the retrained components by experimental studies. We try to perform reinitialization on different parts of the student model and choose the setting with best performance in which the decoder is kept while the backbone and encoder are retrained. More details will be discussed in Section 5.4.", + "bbox": [ + 496, + 428, + 890, + 758 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.4. Dynamic Threshold", + "text_level": 1, + "bbox": [ + 500, + 771, + 687, + 786 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Existing teacher-student frameworks on DAOD set a fixed confidence threshold to select pseudo labels from outputs of the teacher model. However, we observe in experiments that as the teaching process continues, the predicted confidence scores tend to rise, introducing too many pseudo labels which contain much more incorrect labels. Besides, fixed threshold for every category ignores the category dis", + "bbox": [ + 496, + 795, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "19043", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/2ac7f117eee3857dfe0de8b7dc7d93eb39abe1c115c9cc7951a6225ea2167156.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodDetectorpersonridercartruckbustrainmcyclebicyclemAP
FasterRCNN[35](Source)FRCNN26.938.235.618.332.49.625.828.626.9
DA-Faster[9]FRCNN29.240.443.419.738.328.523.732.732.0
UMT[12]FRCNN33.046.748.634.156.546.830.437.341.7
TIA[50]FRCNN34.846.349.731.152.148.637.738.142.3
D-adapt[25]FRCNN40.847.157.533.546.941.433.643.043.0
SIGMA[28]FRCNN44.043.960.331.650.451.531.740.644.2
\\(AT^1\\) [29]FRCNN43.754.162.331.954.449.335.247.947.4
TDD[20]FRCNN50.753.768.235.153.045.138.949.149.2
PT[5]FRCNN40.248.863.430.751.830.635.444.542.7
FCOS[40] (Source)FCOS36.936.344.118.629.38.420.331.928.2
EPM[22]FCOS44.246.658.524.845.229.128.634.639.0
SSAL[33]FCOS45.147.459.424.550.025.726.038.739.6
Def DETR[51] (Source)Def DETR37.739.144.217.226.85.821.635.528.5
SFA[44]Def DETR46.548.662.625.146.229.428.344.041.3
MTTrans[48]Def DETR47.749.965.225.845.933.832.646.543.4
\\(O^2\\text{net}\\)[17]Def DETR48.751.563.631.147.647.838.045.946.8
AQT[24]Def DETR49.352.364.427.753.746.536.046.447.1
MRT(Ours)Def DETR52.851.768.735.958.154.541.047.151.2
", + "bbox": [ + 94, + 87, + 874, + 383 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 1. Results of Cityscapes to Foggy Cityscapes(0.02). \"FRCNN\" denotes Faster R-CNN and \"Def DETR\" denotes Deformable DETR.", + "bbox": [ + 76, + 393, + 890, + 407 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "tribution of samples. To address this issue, we initialize the thresholds for each category by a same value, and dynamically update them based on the predicted confidence scores of the source domain instances. In this way, the thresholds for each category could be updated differently. More details and discussion of the rationality and effectiveness of this method can be found in Appendix.", + "bbox": [ + 75, + 431, + 468, + 537 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 76, + 554, + 209, + 571 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Datasets", + "text_level": 1, + "bbox": [ + 76, + 579, + 179, + 593 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Following existing DAOD approaches [44, 48, 17, 24], we evaluate our method on the following benchmarks.", + "bbox": [ + 76, + 603, + 468, + 633 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Cityscapes to Foggy Cityscapes: Cityscapes[10] is collected from urban scenes containing 2,975 images for training and 500 images for validation. Foggy Cityscapes[37] is constructed by a fog synthesis algorithm from Cityscapes. We use Cityscapes as source domain and Foggy Cityscapes with highest fog density(0.02) as target domain.", + "bbox": [ + 75, + 635, + 468, + 724 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Cityscapes to BDD100k-daytime: BDD100k[47] is a large-scale driving dataset. Its daytime subset containing 36,728 training images and 5,258 validation images is commonly used in DAOD. We used Cityscapes as source domain and BDD100k-daytime as target domain.", + "bbox": [ + 75, + 726, + 468, + 801 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Sim10k to Cityscapes(car): Sim10k[26] is a synthetic dataset from GTA game engine containing 10,000 images. We use Sim10k as source domain and \"car\" instances in Cityscapes as target domain.", + "bbox": [ + 75, + 801, + 468, + 863 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.2. Implementation Details", + "text_level": 1, + "bbox": [ + 500, + 431, + 718, + 448 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We use Deformable DETR [51] as our base detector. For loss coefficients, we set $\\lambda_{unsup} = 1.0$ and initial $\\lambda_{mask} = 1.0$ . For the discriminators, the coefficients of backbone, encoder and decoder is set 0.3, 1.0, 1.0 respectively. We set the weight smooth parameter $\\alpha = 0.9996$ in EMA. For dynamic threshold, we initialize the thresholds for each category by 0.3. For MAE branch, we use a 2-layer asymmetric decoder and a mask ratio of 0.8. We optimize the network by Adam optimizer with initial learning rate $2 \\times 10^{-4}$ and batch size 8. The data augmentation methods include random horizontal flip for weak augmentation, and randomly color jittering, grayscale and Gaussian blurring for strong augmentations. Algorithms are implemented by PyTorch. More implementation details which differ between benchmarks can be seen in Appendix.", + "bbox": [ + 496, + 455, + 890, + 681 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.3. Comparing with Other Methods", + "text_level": 1, + "bbox": [ + 500, + 695, + 784, + 710 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We compare our proposed MRT with other methods on the three benchmarks mentioned above. Our proposed MRT outperforms previous methods, and achieves significant improvements compared with DETR-based methods. As shown in Table 1, for categories with fewer instances (i.e. \"truck\") in Cityscapes to Foggy Cityscapes, MRT performs much better, as the data-efficient MAE branch boost the performance. For confusing categories (i.e. \"bicycle\" and \"motorcycle\"), MRT has a significant performance gain with the help of selective retraining mechanism. As shown in Table 2, on Cityscapes to BDD100k-daytime where the class distribution of target dataset is largely different from", + "bbox": [ + 496, + 719, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_footnote", + "text": "1We run Foggy(0.02) on AT's open source code to get the results instead of its originally reported Foggy(all) for a fair comparison.", + "bbox": [ + 75, + 875, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "19044", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/c73b3874daf2b1478d722192102d932764c93bc6c95e3c153edc1e9db979f869.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodDetectorpersonridercartruckbusmcyclebicyclemAP
FasterRCNN[35](Source)FRCNN28.825.444.117.916.113.922.424.1
DA-Faster[9]FRCNN28.927.444.219.118.014.222.424.9
ICR-CCR-SW[45]FRCNN32.829.345.822.720.614.925.527.4
FCOS[40] (Source)FCOS38.624.854.517.216.315.018.326.4
EPM[22]FCOS39.626.855.818.819.114.520.127.8
Def DETR[51] (Source)Def DETR38.926.755.215.719.710.816.226.2
SFA[44]Def DETR40.227.657.519.123.415.419.228.9
AQT[24]Def DETR38.233.058.417.318.416.923.529.4
O2net[17]Def DETR40.431.258.620.425.014.922.730.5
MTTrans[48]Def DETR44.130.161.525.126.917.723.032.6
MRT(Ours)Def DETR48.430.963.724.725.520.222.633.7
", + "bbox": [ + 119, + 88, + 849, + 277 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/adcf37c42f433f515dac3f4f585442bc06e05b26d02622490138cdc611bafd11.jpg", + "table_caption": [ + "Table 2. Results of Cityscapes to BDD100k-daytime." + ], + "table_footnote": [], + "table_body": "
MethodDetectorcarAP
Faster R-CNN(Source)[35]FRCNN39.4
DA-Faster[9]FRCNN41.9
MeGA-CDA[43]FRCNN44.8
GPA[45]FRCNN47.6
ViSGA[36]FRCNN49.3
KTNet[39]FRCNN50.7
PT[5]FRCNN55.1
FCOS(Source)[40]FCOS42.5
EPM[22]FCOS47.3
SSAL[33]FCOS51.8
Deformable DETR(Source)[51]Def DETR47.4
SFA[44]Def DETR52.6
AQT[24]Def DETR53.4
O2net[17]Def DETR54.1
MTTrans [29]Def DETR57.9
MRT(Ours)Def DETR62.0
", + "bbox": [ + 83, + 324, + 464, + 589 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "source, MRT still achieves leading. As shown in Table 3, on Sim10k to Cityscapes(car), MRT outperforms previous SOTAs, indicating that our proposed method stays effective under larger domain gap.", + "bbox": [ + 75, + 638, + 468, + 700 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.4. Ablation Study and Analysis", + "text_level": 1, + "bbox": [ + 76, + 710, + 333, + 726 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In this section, we provide ablation study and analysis of our proposed approaches. All experiments are conducted on Cityscapes to Foggy Cityscapes.", + "bbox": [ + 75, + 734, + 468, + 779 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Quantitative Ablation Study: The effect of proposed modules are presented in Table 4, from which we can observe: 1) Introducing MAE branch without teacher-student framework (line 2) shows a significant improvement compared with source-only trained model, indicating that MAE is a data-efficient domain adapter. 2) MAE branch, selective retraining and dynamic filter respectively improves the performance by a large margin (line 4-6) when independently", + "bbox": [ + 75, + 779, + 470, + 901 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/14af5fc7bd8b550b61c98e72d13376a4f62e6e89500242730cdc145339925f2f.jpg", + "table_caption": [ + "Table 3. Results of Sim10k to Cityscapes(car)." + ], + "table_footnote": [], + "table_body": "
SourceBaselineDTRetrainMAEmAP
✓28.5
✓✓35.8
✓✓44.9
✓✓✓45.5
✓✓✓✓48.3
✓✓✓✓48.1
✓✓✓✓✓51.2
", + "bbox": [ + 516, + 324, + 877, + 452 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 4. Ablation studies of proposed modules on Cityscapes to Foggy Cityscapes. \"Source\" denotes the source-only trained model. \"Baseline\" denotes the adaptive teacher-student baseline. \"DT\", \"Retrain\" and \"MAE\" denotes proposed dynamic threshold, selective retraining and masked autoencoder branch, respectively.", + "bbox": [ + 498, + 460, + 890, + 532 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "used, illustrating their effectiveness. 3) Retraining combining with MAE refined re-initialization (line 7) further improves the performance, indicating that our proposed design maximizes the advantages of both modules.", + "bbox": [ + 498, + 561, + 890, + 623 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Qualitative visualization analysis: We provide qualitative visualization analysis of pseudo labels and feature distributions. Figure 3 shows the selected pseudo labels. From Figure 3(b) to 3(c), MAE guide the model to provide more pseudo labels, and from Figure 3(c) to 3(d), selective retraining filters out incorrect pseudo labels and predicts closer to ground truth. Figure 4 visualizes the features of two domains by t-SNE. MAE branch provides a much better initialization compared to source-only trained model, and our proposed MRT further bridges the domain gap. More visualization figures can be seen in Appendix.", + "bbox": [ + 496, + 625, + 892, + 792 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Analysis of MAE branch: Table 5 shows the detailed results of MAE ablation. Table 5(a) indicates that relatively high mask ratio yields a nontrivial and meaningful self-supervisory task. Table 5(b) explores the decay strategy of MAE coefficient $\\lambda_{mask}$ . \"no decay\" denotes the MAE loss continually exists with fixed $\\lambda_{mask}$ . \"linear\" denotes $\\lambda_{mask}$ decays linearly during teaching process. \"hard\" de", + "bbox": [ + 496, + 794, + 893, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "19045", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/b01752e886155a4070d7863d647a4929ac0c7ea70d534070a14663140a36fca7.jpg", + "image_caption": [ + "(a) Source-only" + ], + "image_footnote": [], + "bbox": [ + 94, + 93, + 243, + 154 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/4f73a368f397709af7b0f7ff42a4c66dc7298b67340a1ab04aa6c41722b0cf02.jpg", + "image_caption": [ + "(b) Baseline" + ], + "image_footnote": [], + "bbox": [ + 251, + 93, + 401, + 152 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/e5b27c2e05be8f98f50b4787986508537ae0184c2710a1639e325b92ea28d02e.jpg", + "image_caption": [ + "(c) MRT w/o Retrain" + ], + "image_footnote": [], + "bbox": [ + 408, + 93, + 560, + 152 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/ee9677c7894658429c18d35d43299888f100bf44ce74e7227941f507e3b9ecb9.jpg", + "image_caption": [ + "(d) MRT (ours)" + ], + "image_footnote": [], + "bbox": [ + 566, + 93, + 717, + 152 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/57023cc84755db92dd6adc3a942445ac8401f730ac4e9c8dc0be2a3e6ed174ce.jpg", + "image_caption": [ + "(e) Ground truth" + ], + "image_footnote": [], + "bbox": [ + 725, + 93, + 875, + 152 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/22fca1e0697ec39f238ed943d27fa6311fb9c0bbbcaebfa4a9b0fa4f7ff1e4bf.jpg", + "image_caption": [ + "(a) Source-only", + "Figure 4. Qualitative ablation: feature visualization of the two domains on Cityscapes to Foggy Cityscapes by t-SNE. The blue and orange points denote source and target features respectively." + ], + "image_footnote": [], + "bbox": [ + 86, + 229, + 205, + 323 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/1db509e0492abc3c2cc537a65627d028180f11520c8943e31e57047fe32c6c9e.jpg", + "image_caption": [ + "(b) Source+MAE" + ], + "image_footnote": [], + "bbox": [ + 212, + 229, + 333, + 321 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/d305f8924a52b93b4ca583c2c65c024e111bcc8ec8f887a9386c8669eb95f13a.jpg", + "image_caption": [ + "(c) MRT (ours)" + ], + "image_footnote": [], + "bbox": [ + 341, + 229, + 460, + 321 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/64af137aa09e43943ae7586e70d52a7b5ca820e5ef9f982965c8063289505fdf.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Mask ratiomAP
0.547.1
0.848.3
0.946.8
", + "bbox": [ + 106, + 412, + 251, + 477 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/f5877e30ecf4174d1f0332d0f4ee3246f00b07f1792e90173423842cd40c3554.jpg", + "table_caption": [ + "(a) Mask ratio" + ], + "table_footnote": [], + "table_body": "
StrategymAP
No decay47.9
Linear48.2
Hard48.3
", + "bbox": [ + 299, + 412, + 437, + 477 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/905d7367758f90e1d21bb3c3a6f7ea95a24557772a0c747a7471a47df2a8d71c.jpg", + "table_caption": [ + "(b) Coefficient decay" + ], + "table_footnote": [], + "table_body": "
Training datamAP
Source44.5
Source & Target47.0
Target48.3
", + "bbox": [ + 86, + 501, + 269, + 566 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/668dca3091c5643d6062b22fc330cd1f9979b37df8d5d18378bc8e84d4e065fb.jpg", + "table_caption": [ + "(c) MAE Training data" + ], + "table_footnote": [], + "table_body": "
MAE usagemAP
w/o MAE44.9
Pretrain42.7
MAE branch48.3
", + "bbox": [ + 287, + 501, + 447, + 566 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "(d) MAE usage", + "bbox": [ + 321, + 566, + 413, + 580 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 5. Ablation studies of MAE branch. (a) Results of different mask ratios. (b) Results of coefficient decay strategies. (c) The training data that MAE are applied to. (d) The usage of MAE (as a branch or as an independent pretraining stage).", + "bbox": [ + 75, + 590, + 468, + 646 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "notes that we drop the MAE branch after a certain teaching epoch. \"No decay\" receives sub-optimal result for the MAE branch benefits less when more pseudo labels are provided, thus its influence to the overall objective should be lowered at later stage of training. Table 5(c) illustrates that MAE is sensitive to domain shift of the input data. Training with target features receives better performance on target evaluation compared with the inputs that consist source images. Table 5(d) compares the result of MAE branch with the pretrain-finetune paradigm which is commonly used in pretraining tasks, indicating that in DAOD, pretraining on relatively small dataset with distinctive domain characteristics leads the model to over-fit on reconstruction task. MRT use a customised MAE branch to overcome this issue.", + "bbox": [ + 75, + 672, + 467, + 883 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Analysis of Selective Retraining: Utilizing selective", + "bbox": [ + 96, + 885, + 468, + 900 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/39019c2f8f5e6f3ae5d4db0714b424771cb8bea191ce62ac97d7ffbcbb05d4ad.jpg", + "image_caption": [ + "Figure 3. Qualitative ablation: pseudo labels for Foggy Cityscapes. \"Baseline\" denotes the adaptive teacher-student baseline.", + "(a) Retrained module" + ], + "image_footnote": [], + "bbox": [ + 500, + 223, + 705, + 319 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/0fd8840883226dacfd2c8648769411cf6a12f831285c1cbccc081491ce431c34.jpg", + "image_caption": [ + "(b) Re-initialization weights", + "Table 6. Ablation studies of selective retraining. (a) Results of different retrained modules (tick for retrained). \"Bac.\", \"Enc.\" and \"Dec.\" denotes backbone, encoder and decoder respectively. (b) Results of different re-initialization weights." + ], + "image_footnote": [], + "bbox": [ + 720, + 223, + 883, + 320 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "retraining, we periodically re-initialize some components of the model while keeping other components as enhanced parts. In teacher-student framework, we do not re-initialize teacher as has been discussed in Section 4.3. For the student model, we choose the retrained modules through experimental results. Table 6(a) shows that keeping the decoder updated and retraining backbone and decoder gets the best performance. For the re-initialization weights, Table 6(b) shows that MAE refined weights receives the best performance. Further discussion on the selective retraining mechanism can be seen in Appendix.", + "bbox": [ + 496, + 424, + 890, + 590 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 606, + 617, + 622 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this paper, we propose a novel Masked Retraining Teacher-student framework (MRT) on domain adaptive object detection task. Our customized design of masked autoencoder branch helps the student model better capture target domain characteristics and gain knowledge from limited amount of pseudo boxes, and the selective retraining mechanism allows the model to jump out of the local optimum biased to the incorrect pseudo labels. Experiments on three benchmarks confirmed the effectiveness of our model. Extensive ablation experiments demonstrate that every design helps to improve domain adaptation ability of the model.", + "bbox": [ + 496, + 632, + 890, + 797 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "7. Acknowledgements", + "text_level": 1, + "bbox": [ + 500, + 814, + 687, + 830 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "This work was supported by National Natural Science Foundation of China (61925201,62132001), Zhejiang Lab (NO.2022NB0AB05) and CCF-Tencent Open Research Fund.", + "bbox": [ + 496, + 839, + 890, + 898 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "19046", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. Beit: Bert pre-training of image transformers. arXiv preprint arXiv:2106.08254, 2021.3", + "[2] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, et al. Language models are few-shot learners. Advances in neural information processing systems, 33:1877-1901, 2020. 3", + "[3] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In European conference on computer vision, pages 213-229. Springer, 2020. 1, 2", + "[4] Chaoqi Chen, Zebiao Zheng, Yue Huang, Xinghao Ding, and Yizhou Yu. I3net: Implicit instance-invariant network for adapting one-stage object detectors. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12576-12585, 2021. 2", + "[5] Meilin Chen, Weijie Chen, Shicai Yang, Jie Song, Xin chao Wang, Lei Zhang, Yunfeng Yan, Donglian Qi, Yueting Zhuang, Di Xie, et al. Learning domain adaptive object detection with probabilistic teacher. In International Conference on Machine Learning, pages 3040-3055. PMLR, 2022. 1, 2, 6, 7", + "[6] Mark Chen, Alec Radford, Rewon Child, Jeffrey Wu, Heewoo Jun, David Luan, and Ilya Sutskever. Generative pretraining from pixels. In International conference on machine learning, pages 1691-1703. PMLR, 2020. 3", + "[7] Qingchao Chen and Yang Liu. Structure-aware feature fusion for unsupervised domain adaptation. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 10567-10574, 2020. 2", + "[8] Qingchao Chen, Yang Liu, Zhaowen Wang, Ian Wassell, and Kevin Chetty. Re-weighted adversarial adaptation network for unsupervised domain adaptation. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 7976-7985, 2018. 2", + "[9] Yuhua Chen, Wen Li, Christos Sakaridis, Dengxin Dai, and Luc Van Gool. Domain adaptive faster r-cnn for object detection in the wild. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3339-3348, 2018. 1, 2, 6, 7", + "[10] Marius Cordts, Mohamed Omran, Sebastian Ramos, Timo Rehfeld, Markus Enzweiler, Rodrigo Benenson, Uwe Franke, Stefan Roth, and Bernt Schiele. The cityscapes dataset for semantic urban scene understanding. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3213-3223, 2016. 6", + "[11] Zhigang Dai, Bolun Cai, Yugeng Lin, and Junying Chen. Up-detr: Unsupervised pre-training for object detection with transformers. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 1601-1610, 2021. 3", + "[12] Jinhong Deng, Wen Li, Yuhua Chen, and Lixin Duan. Unbiased mean teacher for cross-domain object detection. In" + ], + "bbox": [ + 78, + 114, + 470, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4091-4101, 2021. 2, 6", + "[13] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers), pages 4171–4186, 2019. 3", + "[14] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2020. 3, 4", + "[15] Yaroslav Ganin and Victor Lempitsky. Unsupervised domain adaptation by backpropagation. In International conference on machine learning, pages 1180-1189. PMLR, 2015. 3", + "[16] Golnaz Ghiasi, Tsung-Yi Lin, and Quoc V Le. Dropblock: A regularization method for convolutional networks. Advances in neural information processing systems, 31, 2018. 3", + "[17] Kaixiong Gong, Shuang Li, Shugang Li, Rui Zhang, Chi Harold Liu, and Qiang Chen. Improving transferability for domain adaptive detection transformers. arXiv preprint arXiv:2204.14195, 2022. 2, 6, 7", + "[18] Song Han, Jeff Pool, Sharan Narang, Huizi Mao, Enhao Gong, Shijian Tang, Erich Elsen, Peter Vajda, Manohar Paluri, John Tran, et al. Dsd: Dense-sparse-dense training for deep neural networks. arXiv preprint arXiv:1607.04381, 2016. 2, 3", + "[19] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollar, and Ross Girshick. Masked autoencoders are scalable vision learners. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 16000-16009, 2022. 2, 3, 5", + "[20] Mengzhe He, Yali Wang, Jiaxi Wu, Yiru Wang, Hanqing Li, Bo Li, Weihao Gan, Wei Wu, and Yu Qiao. Cross domain object detection by target-perceived dual branch distillation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9570-9580, 2022. 1, 2, 6", + "[21] Zhenwei He and Lei Zhang. Multi-adversarial faster-rcnn for unrestricted object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6668–6677, 2019. 2", + "[22] Cheng-Chun Hsu, Yi-Hsuan Tsai, Yen-Yu Lin, and Ming-Hsuan Yang. Every pixel matters: Center-aware feature alignment for domain adaptive object detector. In European Conference on Computer Vision, pages 733-748. Springer, 2020. 6, 7", + "[23] Gao Huang, Yixuan Li, Geoff Pleiss, Zhuang Liu, John E Hopcroft, and Kilian Q Weinberger. Snapshot ensembles: Train 1, get m for free. arXiv preprint arXiv:1704.00109, 2017. 3", + "[24] Wei-Jie Huang, Yu-Lin Lu, Shih-Yao Lin, Yusheng Xie, and Yen-Yu Lin. Aqt: Adversarial query transformers for domain" + ], + "bbox": [ + 503, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "19047", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "adaptive object detection. In 31st International Joint Conference on Artificial Intelligence, IJCAI 2022, pages 972-979. International Joint Conferences on Artificial Intelligence, 2022. 2, 6, 7", + "[25] Junguang Jiang, Baixu Chen, Jianmin Wang, and Mingsheng Long. Decoupled adaptation for cross-domain object detection. In International Conference on Learning Representations, 2021. 6", + "[26] Matthew Johnson-Roberson, Charles Barto, Rounak Mehta, Sharath Nittur Sridhar, Karl Rosaen, and Ram Vasudevan. Driving in the matrix: Can virtual worlds replace human-generated annotations for real world tasks? arXiv preprint arXiv:1610.01983, 2016. 6", + "[27] Taekyung Kim, Minki Jeong, Seunghyeon Kim, Seokeon Choi, and Changick Kim. Diversify and match: A domain adaptive representation learning paradigm for object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12456-12465, 2019. 2", + "[28] Wuyang Li, Xinyu Liu, and Yixuan Yuan. Sigma: Semantic-complete graph matching for domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5291-5300, 2022. 2, 6", + "[29] Yu-Jhe Li, Xiaoliang Dai, Chih-Yao Ma, Yen-Cheng Liu, Kan Chen, Bichen Wu, Zijian He, Kris Kitani, and Peter Vajda. Cross-domain adaptive teacher for object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7581-7590, 2022. 1, 2, 6, 7", + "[30] Tsung-Yi Lin, Piotr Dólar, Ross Girshick, Kaiming He, Bharath Hariharan, and Serge Belongie. Feature pyramid networks for object detection. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2117-2125, 2017. 2", + "[31] Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dólár. Focal loss for dense object detection. In Proceedings of the IEEE international conference on computer vision, pages 2980-2988, 2017. 2", + "[32] Wei Liu, Dragomir Anguelov, Dumitru Erhan, Christian Szegedy, Scott Reed, Cheng-Yang Fu, and Alexander C Berg. Ssd: Single shot multibox detector. In European conference on computer vision, pages 21-37. Springer, 2016. 1, 2", + "[33] Muhammad Akhtar Munir, Muhammad Haris Khan, M Sarfraz, and Mohsen Ali. Ssal: Synergizing between selftraining and adversarial learning for domain adaptive object detection. Advances in Neural Information Processing Systems, 34:22770-22782, 2021. 6, 7", + "[34] Mengxue Qu, Yu Wu, Wu Liu, Qiqi Gong, Xiaodan Liang, Olga Russakovsky, Yao Zhao, and Yunchao Wei. Siri: A simple selective retraining mechanism for transformer-based visual grounding. In European Conference on Computer Vision, pages 546-562. Springer, 2022. 2, 3", + "[35] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. Advances in neural information processing systems, 28, 2015. 1, 2, 6, 7" + ], + "bbox": [ + 78, + 90, + 470, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[36] Farzaneh Rezaeanaran, Rakshith Shetty, Rahaf Aljundi, Daniel Olmeda Reino, Shanshan Zhang, and Bernt Schiele. Seeking similarities over differences: Similarity-based domain alignment for adaptive object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 9204-9213, 2021. 2, 7", + "[37] Christos Sakaridis, Dengxin Dai, and Luc Van Gool. Semantic foggy scene understanding with synthetic data. International Journal of Computer Vision, 126(9):973-992, 2018. 6", + "[38] Nitish Srivastava, Geoffrey Hinton, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. Dropout: a simple way to prevent neural networks from overfitting. The journal of machine learning research, 15(1):1929-1958, 2014. 3", + "[39] Kun Tian, Chenghao Zhang, Ying Wang, Shiming Xiang, and Chunhong Pan. Knowledge mining and transferring for domain adaptive object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 9133–9142, 2021. 7", + "[40] Zhi Tian, Chunhua Shen, Hao Chen, and Tong He. Fcos: Fully convolutional one-stage object detection. In Proceedings of the IEEE/CVF international conference on computer vision, pages 9627-9636, 2019. 1, 2, 6, 7", + "[41] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. Videomae: Masked autoencoders are data-efficient learners for self-supervised video pre-training. arXiv preprint arXiv:2203.12602, 2022. 2, 3", + "[42] Pascal Vincent, Hugo Larochelle, Yoshua Bengio, and Pierre-Antoine Manzagol. Extracting and composing robust features with denoising autoencoders. In Proceedings of the 25th international conference on Machine learning, pages 1096-1103, 2008. 3", + "[43] Vibashan Vs, Vikram Gupta, Poojan Oza, Vishwanath A Sindagi, and Vishal M Patel. Mega-cda: Memory guided attention for category-aware unsupervised domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4516-4526, 2021. 7", + "[44] Wen Wang, Yang Cao, Jing Zhang, Fengxiang He, Zheng-Jun Zha, Yonggang Wen, and Dacheng Tao. Exploring sequence feature alignment for domain adaptive detection transformers. In Proceedings of the 29th ACM International Conference on Multimedia, pages 1730-1738, 2021. 2, 6, 7", + "[45] Chang-Dong Xu, Xing-Ran Zhao, Xin Jin, and Xiu-Shen Wei. Exploring categorical regularization for domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11724-11733, 2020. 7", + "[46] Minghao Xu, Hang Wang, Bingbing Ni, Qi Tian, and Wenjun Zhang. Cross-domain detection via graph-induced prototype alignment. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12355-12364, 2020. 2, 3", + "[47] Fisher Yu, Haofeng Chen, Xin Wang, Wenqi Xian, Yingying Chen, Fangchen Liu, Vashisht Madhavan, and Trevor Darell. Bdd100k: A diverse driving dataset for heterogeneous multitask learning. In Proceedings of the IEEE/CVF con" + ], + "bbox": [ + 501, + 92, + 893, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "19048", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "ference on computer vision and pattern recognition, pages 2636-2645, 2020. 6", + "[48] Jinze Yu, Jiaming Liu, Xiaobao Wei, Haoyi Zhou, Yohei Nakata, Denis Gudovskiy, Tomoyuki Okuno, Jianxin Li, Kurt Keutzer, and Shanghang Zhang. Cross-domain object detection with mean-teacher transformer. arXiv preprint arXiv:2205.01643, 2022. 1, 2, 3, 6, 7", + "[49] Dan Zhang, Jingjing Li, Lin Xiong, Lan Lin, Mao Ye, and Shangming Yang. Cycle-consistent domain adaptive faster rcnn. IEEE Access, 7:123903-123911, 2019. 1, 2", + "[50] Liang Zhao and Limin Wang. Task-specific inconsistency alignment for domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14217-14226, 2022. 6", + "[51] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable detr: Deformable transformers for end-to-end object detection. In International Conference on Learning Representations, 2020. 1, 2, 3, 6, 7" + ], + "bbox": [ + 78, + 92, + 468, + 345 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "19049", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/5a41b22e-9755-4ada-9123-4e6d5ca57c32_model.json b/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/5a41b22e-9755-4ada-9123-4e6d5ca57c32_model.json new file mode 100644 index 0000000000000000000000000000000000000000..a7fd4b1c7646a67fa3ec411c77999929ce7b481c --- /dev/null +++ b/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/5a41b22e-9755-4ada-9123-4e6d5ca57c32_model.json @@ -0,0 +1,2312 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.221, + 0.131, + 0.75, + 0.176 + ], + "angle": 0, + "content": "Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection" + }, + { + "type": "text", + "bbox": [ + 0.086, + 0.202, + 0.894, + 0.294 + ], + "angle": 0, + "content": "Zijing Zhao\\(^{1}\\) Sitong Wei\\(^{1}\\) Qingchao Chen\\(^{2}\\) Dehui Li\\(^{3}\\) Yifan Yang\\(^{3}\\) Yuxin Peng\\(^{1}\\) Yang Liu\\(^{1*}\\) \n\\(^{1}\\)Wangxuan Institute of Computer Technology, Peking University \n\\(^{2}\\)National Institute of Health Data Science, Peking University \n\\(^{3}\\)Tencent Intelligent Mobility \nzijingzhao@stu.pku.edu.cn {weisitong, qingchao.chen, pengyuxin, yangliu}@oku.edu.cn \n{dehuili, lvanyang}@tencent.com" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.327, + 0.314, + 0.344 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.359, + 0.474, + 0.751 + ], + "angle": 0, + "content": "Domain adaptive Object Detection (DAOD) leverages a labeled domain (source) to learn an object detector generalizing to a novel domain without annotation (target). Recent advances use a teacher-student framework, i.e., a student model is supervised by the pseudo labels from a teacher model. Though great success, they suffer from the limited number of pseudo boxes with incorrect predictions caused by the domain shift, misleading the student model to get sub-optimal results. To mitigate this problem, we propose Masked Retraining Teacher-student framework (MRT) which leverages masked autoencoder and selective retraining mechanism on detection transformer. Specifically, we present a customized design of masked autoencoder branch, masking the multi-scale feature maps of target images and reconstructing features by the encoder of the student model and an auxiliary decoder. This helps the student model capture target domain characteristics and become a more data-efficient learner to gain knowledge from the limited number of pseudo boxes. Furthermore, we adopt selective retraining mechanism, periodically re-initializing certain parts of the student parameters with masked autoencoder refined weights to allow the model to jump out of the local optimum biased to the incorrect pseudo labels. Experimental results on three DAOD benchmarks demonstrate the effectiveness of our method. Code can be found at https://github.com/JeremyZhao1998/MRT-release." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.779, + 0.21, + 0.795 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.804, + 0.47, + 0.88 + ], + "angle": 0, + "content": "Object detection has a wide range of real-world application scenarios, and has been deeply studied in computer vision researches. CNN-based [35, 32, 40] and transformer-based [3, 51] detectors have shown great success in challenging benchmarks. However, they suffer from domain" + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.332, + 0.706, + 0.465 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.528, + 0.47, + 0.686, + 0.483 + ], + "angle": 0, + "content": "(a) mAP under limited boxes" + }, + { + "type": "image", + "bbox": [ + 0.709, + 0.332, + 0.886, + 0.465 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.711, + 0.47, + 0.884, + 0.484 + ], + "angle": 0, + "content": "(b) Category AP during training" + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.499, + 0.895, + 0.611 + ], + "angle": 0, + "content": "Figure 1. (a) Performance under limited number of box annotations. We adopt MAE in training target images with ground truth labels, but manually reduce the amount of bounding boxes. MAE boosts the performance by a large margin under limited boxes. (b) Performance of Category \"bicycle\" during training. The performance declines rapidly due to the local optimum caused by incorrect pseudo boxes. With the help of retraining (every 40 epochs), the model is able to jump out of the local optimum." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.64, + 0.892, + 0.671 + ], + "angle": 0, + "content": "shift where there is an obvious distribution gap between the pretraining data and the deployed environment." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.672, + 0.893, + 0.839 + ], + "angle": 0, + "content": "To mitigate the performance drop caused by domain shift without extra annotation, unsupervised domain adaptation (UDA) has been studied in classification, segmentation and object detection tasks, where the model is trained on a labeled source domain and an unlabeled target domain, and is expected to generalize well on the target domain. As a branch of UDA, unsupervised domain adaptive object detection (DAOD) researches [9, 49, 29, 48] utilize numerous techniques such as adversarial alignment, image-to-image translation, GNNs and mean teacher training, widely improving domain adaptation performance of object detectors." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.894, + 0.902 + ], + "angle": 0, + "content": "Among these approaches, [29, 48, 5, 20] use a teacher-student framework where a teacher model produces pseudo labels of the unlabeled target images to supervise a student model, and has achieved significant performance gains." + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.888, + 0.221, + 0.9 + ], + "angle": 0, + "content": "*Corresponding author" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19039" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.424 + ], + "angle": 0, + "content": "However, the teaching process faces the challenge of low-quality pseudo labels in which there are limited number of pseudo boxes and incorrect predictions caused by the domain shift. Under such framework, pseudo labels are selected from outputs of the teacher model by a threshold of confidence scores. Selecting large amounts of pseudo labels with lower threshold brings too many incorrect predictions, degrading the performance, while with higher threshold, the limited number of pseudo boxes provides sub-optimal supervision. Blue bars of Figure 1(a) shows that even supervised by ground truth labels without domain shift, the performance drops significantly when the amount of box annotations are reduced. Anyhow, incorrect predictions always exist, leading the model to get stuck at the local optimum. As is shown in Figure 1(b), in the later stage of training, performance of some categories declines rapidly (the blue curve) due to the growing number of incorrect pseudo boxes. Though [29] utilizes adversarial alignment and weak-strong augmentation to minimize the false positive ratio of pseudo labels, they ignore the sub-optimal supervision of the limited number of pseudo boxes, and the impact of incorrect pseudo labels which always exist." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.426, + 0.472, + 0.502 + ], + "angle": 0, + "content": "To address this issue, we propose Masked Retraining Teacher-student framework (MRT) which is built on the baseline of adaptive teacher-student framework for Deformable DETR[51] detector, leveraging masked autoencoder (MAE) and selective retraining mechanism." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.506, + 0.473, + 0.718 + ], + "angle": 0, + "content": "Unlike pretraining MAEs[19, 41] which leverage large-scale training data under a pretrain-finetune paradigm, we present a customized design of MAE branch, randomly masking portions of multi-scale feature maps of the target images and reconstructing the missing features from their contexts by the encoder of the student model and an auxiliary decoder, simultaneously with the detection loss. As a self-supervised task on target images, MAE leads the transformer encoder to gain more intimate knowledge of the target domain from the limited number of pseudo boxes. Empirically, we observe that MAE helps the model encode better features, improving the performance under any amount of supervision and achieving larger gains when fewer box annotations are provided, as is shown in Figure 1(a)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.72, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Furthermore, as the student model is sensitive to the pseudo label noise, we adopt a simple yet effective selective retraining mechanism. Specifically, we periodically re-initialize certain parts of the student parameters to allow the model to jump out of the local optimum biased to the incorrect pseudo labels. Unlike existing retraining approaches [18, 34] that ignore the quality of re-initialization weights, we re-initialize the student model with MAE refined weights to avoid low-quality student weights to impact the teacher model through EMA. In teacher-student framework, an enhanced teacher model helps the student recover rapidly after the re-initialization. As is shown in the orange" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.121 + ], + "angle": 0, + "content": "curve of Figure 1(b), retraining recovers the performance that has been corrupted by noisy pseudo labels." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.122, + 0.895, + 0.319 + ], + "angle": 0, + "content": "We summarize the contribution of this paper as follow: 1) We propose a novel Masked Retraining Teacher-student framework(MRT) for training domain adaptive detection transformers, which is built on the adaptive teacher-student framework baseline and overcomes the problem of low-quality pseudo labels. 2) To the best of our knowledge, we are the first to present that masked autoencoder is a data-efficient domain adapter which helps the model better capture domain characteristics, and the first to adopt selective retraining mechanism in teacher-student framework to help the model jump out of local optimums. 3) Our method outperforms existing approaches by a large margin and achieves state-of-the-art on three DAOD benchmarks." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.332, + 0.642, + 0.348 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.358, + 0.895, + 0.553 + ], + "angle": 0, + "content": "Object detection: Object detection has been deeply studied in computer vision. CNN-based methods[35, 30, 31] present region proposals networks and achieve outstanding performance. One-stage detectors without region proposals [32, 40] simplify the structure and perform faster. Recently, transformer-based models [3, 51] are also developed in object detection, exploring token-wise dependencies for context modeling. These methods all focus on supervised learning, while we aim to generalize the model to a novel domain without extra annotations. In this work, we employ Deformable DETR[51] as the detector due to its simplified one-stage structure and the flexible transfer-learning ability of the transformer architecture." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.554, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Domain adaptive object detection: Domain adaptive object detection (DAOD) is raised to overcome the domain shift problem in object detection. As a pioneer work of DAOD, [9] investigates adversarial feature alignment for Faster R-CNN. Following [9], [21, 8, 27, 7, 4, 36, 46] apply different aspects of feature alignments, and [44, 24, 17] elaborately design alignments for transformer architectures. Numerous techniques such as image-to-image translation[49], graph reasoning[28, 48] and pseudo label self-training[12, 29, 48] have also been studied for DAOD. Among existing approaches, methods utilizing teacher-student framework achieve leading position in experimental performances. [29] utilizes adversarial alignment and weak-strong augmentation to minimize the false positive ratio of pseudo labels. [20] reduces domain shift by incorporating target object knowledge through self-distillation. [5] employs uncertainty-guided self-training to promote both classification and localization adaptations. Though great success, they ignore the low-quality pseudo labels which contains limited number of bounding boxes and incorrect predictions. We build our method on the baseline of teacher-student framework with adversarial alignment, introducing MAE and selective retraining to overcome such problem." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "19040" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.455 + ], + "angle": 0, + "content": "Masked autoencoders: Autoencoding is a classical representation learning method, utilizing an encoder to map the input to a latent representation and a decoder to reconstruct the input. Denoising autoencoders (DAE)[42] corrupt the input signal and learn to reconstruct the original, uncorrupted signal. Recently, DAE methods are widely used in large-scale pretraining tasks in both language models [13, 2] and vision models [6, 14, 1], holding out a portion of the input and train models to predict the missing content. The influential MAE[19] randomly masks image patches with a high portion and reconstruct the missing pixels by an asymmetric architecture to pretrain a vision transformer that generalize well in downstream tasks. [41] explores MAE in video pretraining, raising the point that MAE is a data-efficient learner and domain shift is an important factor during pretraining. [11] employs attention mask for DETR decoder as an unsupervised pretraining task. However, these works all focus on pretraining transformer-based backbones with all accessible data to generalize to downstream tasks, without considering domain shift. We empirically observe that feeding MAE with inputs from mismatched domain provides sub-optimal results. Thus, we apply MAE only on target images for domain adaptation, guiding the encoder to better capture target domain characteristics." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.455, + 0.473, + 0.759 + ], + "angle": 0, + "content": "Overcoming local optimums: Optimizing neural networks faces the challenge of local optimums. Regularization methods such as Dropout[38] and DropBlock[16] try to avoid the model from over-fitting or getting trapped in local minimums by introducing randomness. [23] introduces cyclic learning rate, but is inapplicable for transformer-based models. Recent studies show that retraining is a simple yet effective way for transformers. [18] proposes DSD retraining with reference to model pruning to avoid overfitting to noisy data, and [34] proposes selective retraining mechanism for visual grounding transformers to converge to better minimums. To the best of our knowledge, we are the first to adopt retraining in teacher-student framework to overcome the impact of incorrect pseudo labels. Under such framework, quality of the re-initialization weights become significant, which has not been studied in existing retraining approaches, since the teacher model may be influenced by the re-initialized student weights to provide sub-optimal pseudo labels. We re-initializing the student parameters with MAE refined weights to avoid the problem." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.774, + 0.396, + 0.79 + ], + "angle": 0, + "content": "3. Problem Formulation and Baseline" + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.8, + 0.281, + 0.815 + ], + "angle": 0, + "content": "3.1. Problem Formulation" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.824, + 0.47, + 0.903 + ], + "angle": 0, + "content": "We first review the problem formulation of unsupervised DAOD. Given a labeled source dataset \\( D_{s} = \\{(x_{s}^{i},y_{s}^{i})\\}_{i = 1}^{N_{s}} \\) sized \\( N_{s} \\) and an unlabeled target dataset \\( D_{t} = \\{x_{t}^{i}\\}_{i = 1}^{N_{t}} \\) sized \\( N_{t} \\), where \\( x \\) denotes an image and \\( y = (b,c) \\) represents an annotation for object detection including bounding" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.138 + ], + "angle": 0, + "content": "box \\(b\\) and the corresponding category \\(c\\), we train a domain adaptive detector with both \\(D_{s}\\) and \\(D_{t}\\), and evaluate the detection performance on data in the target domain." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.146, + 0.878, + 0.162 + ], + "angle": 0, + "content": "3.2. Adaptive Teacher-student Baseline Revisited" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.169, + 0.892, + 0.228 + ], + "angle": 0, + "content": "Recent advances [46, 48] use a teacher-student framework combined with adversarial alignment and achieve SOTA. Our method is built on the adaptive teacher-student framework as baseline. We revisit the baseline as follow." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.23, + 0.892, + 0.336 + ], + "angle": 0, + "content": "Teacher-student framework: A teacher model \\( T \\) and a student model \\( S \\) share the same structure of backbone, encoder and decoder. The teacher takes a weakly augmented target image \\( x_{t} \\) and produces pseudo labels \\( (\\hat{b}_{t},\\hat{c}_{t}) \\). The student takes both source and target images which are strongly augmented. Supervised loss \\( \\mathcal{L}_{sup} \\) is calculated on \\( x_{s} \\) with their ground truth labels same as [51]:" + }, + { + "type": "equation", + "bbox": [ + 0.511, + 0.344, + 0.892, + 0.363 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {s u p} = \\mathcal {L} _ {b o x} ^ {S} \\left(x _ {s}, y _ {s}\\right) + \\mathcal {L} _ {g i o u} ^ {S} \\left(x _ {s}, y _ {s}\\right) + \\mathcal {L} _ {c l s} ^ {S} \\left(x _ {s}, y _ {s}\\right) \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.372, + 0.892, + 0.403 + ], + "angle": 0, + "content": "while \\( x_{t} \\) receive supervision from pseudo labels, but only in classification task following [46] as unsupervised loss:" + }, + { + "type": "equation", + "bbox": [ + 0.611, + 0.411, + 0.892, + 0.43 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {u n s u p} = \\mathcal {L} _ {c l s} ^ {S} \\left(x _ {t}, \\hat {b} _ {t}, \\hat {c} _ {t}\\right) \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.439, + 0.892, + 0.47 + ], + "angle": 0, + "content": "The teacher is only updated by Exponential Moving Average (EMA) from the student without gradient accumulation:" + }, + { + "type": "equation", + "bbox": [ + 0.619, + 0.484, + 0.892, + 0.501 + ], + "angle": 0, + "content": "\\[\n\\theta_ {t} \\leftarrow \\alpha \\theta_ {t} + (1 - \\alpha) \\theta_ {s} \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.506, + 0.892, + 0.536 + ], + "angle": 0, + "content": "where \\(\\theta_{t}\\) and \\(\\theta_{s}\\) denotes the model parameters of teacher and student respectively, and \\(\\alpha\\) is a hyper-parameter." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.537, + 0.892, + 0.657 + ], + "angle": 0, + "content": "Discriminators for adversarial alignment: Domain discriminators \\(D\\) are placed after certain components to predict the domain label of the features, updated by BCE loss. On Deformable DETR detector, we set discriminators for the backbone, encoder and decoder to provide global level, token-wise multi-scale feature level and instance level alignment respectively, and \\(\\mathcal{L}_{dis}\\) denotes their weighted sum. The adversarial optimization objective is formulated:" + }, + { + "type": "equation", + "bbox": [ + 0.622, + 0.668, + 0.892, + 0.69 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {a d v} = \\max _ {S} \\min _ {D} \\mathcal {L} _ {d i s} \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.698, + 0.892, + 0.744 + ], + "angle": 0, + "content": "where \\( S, D \\) denotes the student and discriminators respectively. Gradient Reverse Layers(GRL)[15] is adopted for min-max optimization. Overall objective of the student is:" + }, + { + "type": "equation", + "bbox": [ + 0.561, + 0.754, + 0.892, + 0.771 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {t e a c h}} = \\mathcal {L} _ {\\sup } + \\mathcal {L} _ {\\operatorname {a d v}} + \\lambda_ {\\text {u n s u p}} \\mathcal {L} _ {\\text {u n s u p}} \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.781, + 0.892, + 0.855 + ], + "angle": 0, + "content": "where \\(\\lambda_{unsup}\\) is the hyper-parameter, while the teacher is updated only by EMA which has been discussed. Before teaching process, the model will first be trained with \\(\\mathcal{L}_{sup}\\) using annotated source data \\(D_{s}\\), and both teacher and student model will be initialized with such parameters." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.892, + 0.902 + ], + "angle": 0, + "content": "The adaptive teacher-student baseline on Deformable DETR outperforms most existing DAOD approaches. However, the problem of low-quality pseudo labels still exist," + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "19041" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.11, + 0.092, + 0.882, + 0.368 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.373, + 0.895, + 0.459 + ], + "angle": 0, + "content": "Figure 2. Overview Masked Retraining Teacher-student framework(MRT). The adaptive teacher-student baseline consists of a teacher model which takes weakly-augmented target images and produces pseudo labels, and a student model which takes strongly augmented source and target images, supervised by ground truth labels and pseudo labels respectively. Adversarial alignment are applied on backbone, encoder and decoder. Our proposed MAE branch masks feature maps of target images, and and reconstructs the feature by student encoder and an auxiliary decoder. Our proposed selective retraining mechanism periodically re-initialize certain parts of the student parameters as highlighted. The teacher model is updated only by EMA from the student model. Empirically, we use the teacher model at inference time." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.481, + 0.472, + 0.543 + ], + "angle": 0, + "content": "leading the model to sub-optimal results, as has been shown in Figure 1. Our proposed method overcomes this issue by introducing MAE branch and selective retraining mechanism which will be elaborated in the following section." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.561, + 0.251, + 0.579 + ], + "angle": 0, + "content": "4. Proposed Method" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.589, + 0.251, + 0.604 + ], + "angle": 0, + "content": "4.1. Method Overview" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.614, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Our proposed method can be overviewed in Figure 2, which is built on the adaptive teacher-student baseline discussed in Section 3.2. We propose a customized design of masked autoencoder(MAE) branch for student model, randomly masking a portion of the multi-scale feature maps of the target images, feeding them into the encoder, and introducing an auxiliary decoder to reconstruct the missing features from their contexts. As a self-supervised task on target images, MAE leads the transformer encoder to gain more intimate knowledge of the target domain, thus helps the model better capture target domain characteristics and boosts the performance when the amount of pseudo boxes are limited. Employing selective retraining mechanism, we periodically re-initialize parts of the student parameters with the MAE refined weights, as is illustrated in Figure 2 with marked units, while the teacher model is continually updated via exponential moving average (EMA) from the student model. In this way, the teacher model continually produces relatively high-quality pseudo labels without be" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.481, + 0.892, + 0.619 + ], + "angle": 0, + "content": "ing corrupted by re-initialized low-quality student weights, and the student model is allowed to jump out of the local optimum biased to the incorrect pseudo boxes. Selecting pseudo labels from outputs of the teacher is also important. A fixed confidence threshold is often used, but is unaware of the imbalance sample class distribution and the training period. We propose a dynamic threshold strategy to set different thresholds for each category dynamically during training, selecting appropriate amount of pseudo boxes." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.632, + 0.761, + 0.648 + ], + "angle": 0, + "content": "4.2. Masked Autoencoder Branch" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.657, + 0.892, + 0.779 + ], + "angle": 0, + "content": "We propose a customized design of MAE branch for the student model to better capture target domain characteristic as a self-supervised domain adapter, and to effectively gain knowledge from the limited number of high-quality pseudo boxes. The multi-scale feature maps of target images will be masked and fed into the student encoder, and reconstructed by an auxiliary decoder. The masking and reconstructing processes are elaborated as follows." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.893, + 0.902 + ], + "angle": 0, + "content": "Feature masking: Unlike ViT [14] backbone which directly takes image patches as the input, the Deformable DETR encoder takes the multi-scale feature maps \\(\\{z_{i}\\in\\) \\(\\mathbb{R}^{C_i\\times H_i\\times W_i}\\}_{i = 1}^K\\) which are projected from the output of the backbone, where \\(K\\) denotes the number of scales. We randomly generate masking \\(\\{m_i\\in \\{0,1\\}^{H_i\\times W_i}\\}_{i = 1}^K\\) for every scale of the feature maps with the same masking ratio. The deformable attention relies on the spatial structure of the" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19042" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.198 + ], + "angle": 0, + "content": "feature maps to generate reference points and sampling locations that is used to choose points on the value matrix to perform sparse attention, so the spatial structure of the input cannot be serialized. As a result, we set the masked portion of the corresponding value matrix to zero in deformable attention to perform zero-masking, unlike [19] that only sends unmasked patches as a serialized input to ViT." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.198, + 0.471, + 0.409 + ], + "angle": 0, + "content": "Reconstruction: The encoder takes the masked feature maps, and further encodes the feature maps with deformable attention. On the output features of the encoder, we fill the masked portion with a shared mask query \\( q_{m} \\) and send them to an auxiliary MAE decoder \\( S_{m} \\) to reconstruct the feature map. Following [19], we adopt an asymmetric lightweight decoder. Since the last layer of the backbone outputs, i.e., \\( z_{K} \\) contains all the semantic information, we only reconstruct it to speed up convergence and reduce computation. The last layer of MAE decoder is a linear projection whose output channels equals to the channels of \\( z_{K} \\). Eventually, we compute mean square error (MSE) between the reconstructed and original features, but only on the masked portion, formulated as:" + }, + { + "type": "equation", + "bbox": [ + 0.16, + 0.415, + 0.469, + 0.431 + ], + "angle": 0, + "content": "\\[\n\\hat {z} _ {K} = S _ {m} \\left(S _ {e} \\left(\\operatorname {m a s k} \\left(m, x _ {t}\\right)\\right), q _ {m}\\right) \\tag {6}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.09, + 0.435, + 0.469, + 0.451 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {m a s k}} = \\mathcal {L} _ {\\text {M S E}} \\left(\\operatorname {m a s k} \\left(m _ {K}, z _ {K} ^ {\\prime}\\right), \\operatorname {m a s k} \\left(m _ {K}, z _ {K}\\right)\\right) \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.457, + 0.469, + 0.486 + ], + "angle": 0, + "content": "where \\( S_{e}, S_{m}, q_{m} \\) denotes the encoder of student model, the auxiliary MAE decoder and the mask query respectively." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.487, + 0.469, + 0.728 + ], + "angle": 0, + "content": "Training data: Note that although student model takes both source and target images, we employ MAE only on target images, since DAOD aims to train the detector to perform better on the unlabeled target domain, and applying MAE with source images leads the model to generate source domain features with sub-optimal performance. Employing MAE on target images helps the student encoder to gain more intimate knowledge of the target domain, and boosts performance when high-quality pseudo labels are limited. We apply MAE on student model instead of teacher, for it is the student model who suffers from sub-optimal supervision of the limited pseudo boxes. Besides, the teacher model is not supervised by any detection loss. Employing MAE on the teacher model creates an encoder that is incompatible with the decoder and detection head, thus is unable to provide meaningful pseudo labels." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.728, + 0.469, + 0.879 + ], + "angle": 0, + "content": "Training strategy: We train the MAE branch and detection loss simultaneously instead of following the pretrainfinetune paradigm, since pretraining leads the model to over-fit to reconstruction task due to the relatively small dataset with distinctive domain characteristics. Before the teaching process, we first train the model with \\(\\mathcal{L}_{sup}\\) in Equation(1) together with \\(\\mathcal{L}_{mask}\\) in Equation(7) to produce an enhanced initialization \\(\\theta_{mask}\\) for teaching, and as a refined re-initialization for selective retraining. The overall objective of student model in teaching process is:" + }, + { + "type": "equation", + "bbox": [ + 0.18, + 0.886, + 0.469, + 0.901 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} = \\mathcal {L} _ {\\text {t e a c h}} + \\lambda_ {\\text {m a s k}} \\mathcal {L} _ {\\text {m a s k}} \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.197 + ], + "angle": 0, + "content": "where \\(\\mathcal{L}_{\\text {teach }}\\) has been formulated in Equation(5), and \\(\\lambda_{mask}\\) is the coefficient of \\(\\mathcal{L}_{mask}\\) in Equation(7). As the teaching process continues, adequate amount of pseudo boxes will be produced, and the influence of \\(\\mathcal{L}_{mask}\\) should be lowered to avoid the encoder over-fitting to reconstruction task. As a result, We decay \\(\\lambda_{mask}\\) as teaching continues. More details will be discussed in Section 5.4." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.208, + 0.783, + 0.224 + ], + "angle": 0, + "content": "4.3. Selective Retraining Mechanism" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.232, + 0.892, + 0.428 + ], + "angle": 0, + "content": "The transformer-based models tend to over-fit without large-scale training data, especially when noisy annotations are included. Here in our case, pseudo labels always contain noise since they are provided by the updating teacher model instead of ground truths. As is shown in Figure 1(b), in later stage of the teaching process, performance of certain categories are severely influenced due to the over-fitting to the incorrect pseudo labels. Worse still, since the teacher model is continually updated via EMA from student model, it could also by affected and produces even worse pseudo labels. We adopt selective retraining mechanism on student branch to help student model jump out of local optimums biased to incorrect pseudo labels." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.429, + 0.892, + 0.76 + ], + "angle": 0, + "content": "To be specific, during teaching period, we continually update the teacher model via EMA without retraining it, but periodically re-initialize parts of the student model with the MAE refined parameters \\(\\theta_{mask}\\) which has been discussed in Section 4.2. Though \\(\\theta_{mask}\\) do not contain detection knowledge, its target domain encoding ability has not been corrupted by noisy pseudo labels. After re-initialization, the retrained components are allowed to leave the local optimum and can be guided by the fixed parts which can be regarded as better trained, and by an enhanced teacher which is continually updated. We do not retrain the teacher model since re-initialization cause a sudden drop of pseudo label quality, thus deteriorate the teaching process. We re-initialize the student model with MAE refined weights \\(\\theta_{mask}\\) rather than source-only trained weights or random weights for a quicker recovery, preventing its negative influence to teacher via EMA. We choose the retrained components by experimental studies. We try to perform reinitialization on different parts of the student model and choose the setting with best performance in which the decoder is kept while the backbone and encoder are retrained. More details will be discussed in Section 5.4." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.772, + 0.689, + 0.787 + ], + "angle": 0, + "content": "4.4. Dynamic Threshold" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Existing teacher-student frameworks on DAOD set a fixed confidence threshold to select pseudo labels from outputs of the teacher model. However, we observe in experiments that as the teaching process continues, the predicted confidence scores tend to rise, introducing too many pseudo labels which contain much more incorrect labels. Besides, fixed threshold for every category ignores the category dis" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "19043" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.095, + 0.088, + 0.875, + 0.384 + ], + "angle": 0, + "content": "
MethodDetectorpersonridercartruckbustrainmcyclebicyclemAP
FasterRCNN[35](Source)FRCNN26.938.235.618.332.49.625.828.626.9
DA-Faster[9]FRCNN29.240.443.419.738.328.523.732.732.0
UMT[12]FRCNN33.046.748.634.156.546.830.437.341.7
TIA[50]FRCNN34.846.349.731.152.148.637.738.142.3
D-adapt[25]FRCNN40.847.157.533.546.941.433.643.043.0
SIGMA[28]FRCNN44.043.960.331.650.451.531.740.644.2
\\(AT^1\\) [29]FRCNN43.754.162.331.954.449.335.247.947.4
TDD[20]FRCNN50.753.768.235.153.045.138.949.149.2
PT[5]FRCNN40.248.863.430.751.830.635.444.542.7
FCOS[40] (Source)FCOS36.936.344.118.629.38.420.331.928.2
EPM[22]FCOS44.246.658.524.845.229.128.634.639.0
SSAL[33]FCOS45.147.459.424.550.025.726.038.739.6
Def DETR[51] (Source)Def DETR37.739.144.217.226.85.821.635.528.5
SFA[44]Def DETR46.548.662.625.146.229.428.344.041.3
MTTrans[48]Def DETR47.749.965.225.845.933.832.646.543.4
\\(O^2\\text{net}\\)[17]Def DETR48.751.563.631.147.647.838.045.946.8
AQT[24]Def DETR49.352.364.427.753.746.536.046.447.1
MRT(Ours)Def DETR52.851.768.735.958.154.541.047.151.2
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.394, + 0.892, + 0.409 + ], + "angle": 0, + "content": "Table 1. Results of Cityscapes to Foggy Cityscapes(0.02). \"FRCNN\" denotes Faster R-CNN and \"Def DETR\" denotes Deformable DETR." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.433, + 0.47, + 0.539 + ], + "angle": 0, + "content": "tribution of samples. To address this issue, we initialize the thresholds for each category by a same value, and dynamically update them based on the predicted confidence scores of the source domain instances. In this way, the thresholds for each category could be updated differently. More details and discussion of the rationality and effectiveness of this method can be found in Appendix." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.555, + 0.21, + 0.572 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.58, + 0.18, + 0.594 + ], + "angle": 0, + "content": "5.1. Datasets" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.604, + 0.469, + 0.635 + ], + "angle": 0, + "content": "Following existing DAOD approaches [44, 48, 17, 24], we evaluate our method on the following benchmarks." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.636, + 0.469, + 0.726 + ], + "angle": 0, + "content": "Cityscapes to Foggy Cityscapes: Cityscapes[10] is collected from urban scenes containing 2,975 images for training and 500 images for validation. Foggy Cityscapes[37] is constructed by a fog synthesis algorithm from Cityscapes. We use Cityscapes as source domain and Foggy Cityscapes with highest fog density(0.02) as target domain." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.727, + 0.469, + 0.802 + ], + "angle": 0, + "content": "Cityscapes to BDD100k-daytime: BDD100k[47] is a large-scale driving dataset. Its daytime subset containing 36,728 training images and 5,258 validation images is commonly used in DAOD. We used Cityscapes as source domain and BDD100k-daytime as target domain." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.803, + 0.469, + 0.864 + ], + "angle": 0, + "content": "Sim10k to Cityscapes(car): Sim10k[26] is a synthetic dataset from GTA game engine containing 10,000 images. We use Sim10k as source domain and \"car\" instances in Cityscapes as target domain." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.432, + 0.719, + 0.449 + ], + "angle": 0, + "content": "5.2. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.457, + 0.892, + 0.683 + ], + "angle": 0, + "content": "We use Deformable DETR [51] as our base detector. For loss coefficients, we set \\(\\lambda_{unsup} = 1.0\\) and initial \\(\\lambda_{mask} = 1.0\\). For the discriminators, the coefficients of backbone, encoder and decoder is set 0.3, 1.0, 1.0 respectively. We set the weight smooth parameter \\(\\alpha = 0.9996\\) in EMA. For dynamic threshold, we initialize the thresholds for each category by 0.3. For MAE branch, we use a 2-layer asymmetric decoder and a mask ratio of 0.8. We optimize the network by Adam optimizer with initial learning rate \\(2 \\times 10^{-4}\\) and batch size 8. The data augmentation methods include random horizontal flip for weak augmentation, and randomly color jittering, grayscale and Gaussian blurring for strong augmentations. Algorithms are implemented by PyTorch. More implementation details which differ between benchmarks can be seen in Appendix." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.696, + 0.785, + 0.712 + ], + "angle": 0, + "content": "5.3. Comparing with Other Methods" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.892, + 0.901 + ], + "angle": 0, + "content": "We compare our proposed MRT with other methods on the three benchmarks mentioned above. Our proposed MRT outperforms previous methods, and achieves significant improvements compared with DETR-based methods. As shown in Table 1, for categories with fewer instances (i.e. \"truck\") in Cityscapes to Foggy Cityscapes, MRT performs much better, as the data-efficient MAE branch boost the performance. For confusing categories (i.e. \"bicycle\" and \"motorcycle\"), MRT has a significant performance gain with the help of selective retraining mechanism. As shown in Table 2, on Cityscapes to BDD100k-daytime where the class distribution of target dataset is largely different from" + }, + { + "type": "page_footnote", + "bbox": [ + 0.076, + 0.875, + 0.469, + 0.901 + ], + "angle": 0, + "content": "1We run Foggy(0.02) on AT's open source code to get the results instead of its originally reported Foggy(all) for a fair comparison." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19044" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.12, + 0.089, + 0.851, + 0.279 + ], + "angle": 0, + "content": "
MethodDetectorpersonridercartruckbusmcyclebicyclemAP
FasterRCNN[35](Source)FRCNN28.825.444.117.916.113.922.424.1
DA-Faster[9]FRCNN28.927.444.219.118.014.222.424.9
ICR-CCR-SW[45]FRCNN32.829.345.822.720.614.925.527.4
FCOS[40] (Source)FCOS38.624.854.517.216.315.018.326.4
EPM[22]FCOS39.626.855.818.819.114.520.127.8
Def DETR[51] (Source)Def DETR38.926.755.215.719.710.816.226.2
SFA[44]Def DETR40.227.657.519.123.415.419.228.9
AQT[24]Def DETR38.233.058.417.318.416.923.529.4
O2net[17]Def DETR40.431.258.620.425.014.922.730.5
MTTrans[48]Def DETR44.130.161.525.126.917.723.032.6
MRT(Ours)Def DETR48.430.963.724.725.520.222.633.7
" + }, + { + "type": "table_caption", + "bbox": [ + 0.325, + 0.289, + 0.645, + 0.303 + ], + "angle": 0, + "content": "Table 2. Results of Cityscapes to BDD100k-daytime." + }, + { + "type": "table", + "bbox": [ + 0.084, + 0.325, + 0.465, + 0.59 + ], + "angle": 0, + "content": "
MethodDetectorcarAP
Faster R-CNN(Source)[35]FRCNN39.4
DA-Faster[9]FRCNN41.9
MeGA-CDA[43]FRCNN44.8
GPA[45]FRCNN47.6
ViSGA[36]FRCNN49.3
KTNet[39]FRCNN50.7
PT[5]FRCNN55.1
FCOS(Source)[40]FCOS42.5
EPM[22]FCOS47.3
SSAL[33]FCOS51.8
Deformable DETR(Source)[51]Def DETR47.4
SFA[44]Def DETR52.6
AQT[24]Def DETR53.4
O2net[17]Def DETR54.1
MTTrans [29]Def DETR57.9
MRT(Ours)Def DETR62.0
" + }, + { + "type": "table_caption", + "bbox": [ + 0.133, + 0.6, + 0.415, + 0.615 + ], + "angle": 0, + "content": "Table 3. Results of Sim10k to Cityscapes(car)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.64, + 0.47, + 0.701 + ], + "angle": 0, + "content": "source, MRT still achieves leading. As shown in Table 3, on Sim10k to Cityscapes(car), MRT outperforms previous SOTAs, indicating that our proposed method stays effective under larger domain gap." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.711, + 0.334, + 0.727 + ], + "angle": 0, + "content": "5.4. Ablation Study and Analysis" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.47, + 0.78 + ], + "angle": 0, + "content": "In this section, we provide ablation study and analysis of our proposed approaches. All experiments are conducted on Cityscapes to Foggy Cityscapes." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Quantitative Ablation Study: The effect of proposed modules are presented in Table 4, from which we can observe: 1) Introducing MAE branch without teacher-student framework (line 2) shows a significant improvement compared with source-only trained model, indicating that MAE is a data-efficient domain adapter. 2) MAE branch, selective retraining and dynamic filter respectively improves the performance by a large margin (line 4-6) when independently" + }, + { + "type": "table", + "bbox": [ + 0.517, + 0.325, + 0.879, + 0.453 + ], + "angle": 0, + "content": "
SourceBaselineDTRetrainMAEmAP
✓28.5
✓✓35.8
✓✓44.9
✓✓✓45.5
✓✓✓✓48.3
✓✓✓✓48.1
✓✓✓✓✓51.2
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.462, + 0.892, + 0.533 + ], + "angle": 0, + "content": "Table 4. Ablation studies of proposed modules on Cityscapes to Foggy Cityscapes. \"Source\" denotes the source-only trained model. \"Baseline\" denotes the adaptive teacher-student baseline. \"DT\", \"Retrain\" and \"MAE\" denotes proposed dynamic threshold, selective retraining and masked autoencoder branch, respectively." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.563, + 0.892, + 0.624 + ], + "angle": 0, + "content": "used, illustrating their effectiveness. 3) Retraining combining with MAE refined re-initialization (line 7) further improves the performance, indicating that our proposed design maximizes the advantages of both modules." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.626, + 0.893, + 0.793 + ], + "angle": 0, + "content": "Qualitative visualization analysis: We provide qualitative visualization analysis of pseudo labels and feature distributions. Figure 3 shows the selected pseudo labels. From Figure 3(b) to 3(c), MAE guide the model to provide more pseudo labels, and from Figure 3(c) to 3(d), selective retraining filters out incorrect pseudo labels and predicts closer to ground truth. Figure 4 visualizes the features of two domains by t-SNE. MAE branch provides a much better initialization compared to source-only trained model, and our proposed MRT further bridges the domain gap. More visualization figures can be seen in Appendix." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.894, + 0.903 + ], + "angle": 0, + "content": "Analysis of MAE branch: Table 5 shows the detailed results of MAE ablation. Table 5(a) indicates that relatively high mask ratio yields a nontrivial and meaningful self-supervisory task. Table 5(b) explores the decay strategy of MAE coefficient \\(\\lambda_{mask}\\). \"no decay\" denotes the MAE loss continually exists with fixed \\(\\lambda_{mask}\\). \"linear\" denotes \\(\\lambda_{mask}\\) decays linearly during teaching process. \"hard\" de" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19045" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.095, + 0.094, + 0.245, + 0.155 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.127, + 0.159, + 0.213, + 0.171 + ], + "angle": 0, + "content": "(a) Source-only" + }, + { + "type": "image", + "bbox": [ + 0.252, + 0.094, + 0.403, + 0.154 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.293, + 0.159, + 0.362, + 0.171 + ], + "angle": 0, + "content": "(b) Baseline" + }, + { + "type": "image", + "bbox": [ + 0.41, + 0.094, + 0.561, + 0.154 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.428, + 0.159, + 0.543, + 0.171 + ], + "angle": 0, + "content": "(c) MRT w/o Retrain" + }, + { + "type": "image", + "bbox": [ + 0.568, + 0.094, + 0.718, + 0.154 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.601, + 0.159, + 0.686, + 0.171 + ], + "angle": 0, + "content": "(d) MRT (ours)" + }, + { + "type": "image", + "bbox": [ + 0.726, + 0.094, + 0.876, + 0.154 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.756, + 0.159, + 0.846, + 0.171 + ], + "angle": 0, + "content": "(e) Ground truth" + }, + { + "type": "image_caption", + "bbox": [ + 0.107, + 0.187, + 0.86, + 0.203 + ], + "angle": 0, + "content": "Figure 3. Qualitative ablation: pseudo labels for Foggy Cityscapes. \"Baseline\" denotes the adaptive teacher-student baseline." + }, + { + "type": "image", + "bbox": [ + 0.087, + 0.231, + 0.207, + 0.324 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.103, + 0.328, + 0.188, + 0.34 + ], + "angle": 0, + "content": "(a) Source-only" + }, + { + "type": "image", + "bbox": [ + 0.214, + 0.231, + 0.334, + 0.323 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.226, + 0.328, + 0.323, + 0.34 + ], + "angle": 0, + "content": "(b) Source+MAE" + }, + { + "type": "image", + "bbox": [ + 0.343, + 0.231, + 0.462, + 0.323 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.36, + 0.328, + 0.444, + 0.34 + ], + "angle": 0, + "content": "(c) MRT (ours)" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.356, + 0.47, + 0.399 + ], + "angle": 0, + "content": "Figure 4. Qualitative ablation: feature visualization of the two domains on Cityscapes to Foggy Cityscapes by t-SNE. The blue and orange points denote source and target features respectively." + }, + { + "type": "table", + "bbox": [ + 0.107, + 0.413, + 0.253, + 0.478 + ], + "angle": 0, + "content": "
Mask ratiomAP
0.547.1
0.848.3
0.946.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.137, + 0.479, + 0.222, + 0.49 + ], + "angle": 0, + "content": "(a) Mask ratio" + }, + { + "type": "table", + "bbox": [ + 0.3, + 0.413, + 0.438, + 0.478 + ], + "angle": 0, + "content": "
StrategymAP
No decay47.9
Linear48.2
Hard48.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.306, + 0.479, + 0.432, + 0.49 + ], + "angle": 0, + "content": "(b) Coefficient decay" + }, + { + "type": "table", + "bbox": [ + 0.088, + 0.502, + 0.271, + 0.568 + ], + "angle": 0, + "content": "
Training datamAP
Source44.5
Source & Target47.0
Target48.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.111, + 0.568, + 0.248, + 0.581 + ], + "angle": 0, + "content": "(c) MAE Training data" + }, + { + "type": "table", + "bbox": [ + 0.289, + 0.502, + 0.449, + 0.568 + ], + "angle": 0, + "content": "
MAE usagemAP
w/o MAE44.9
Pretrain42.7
MAE branch48.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.323, + 0.568, + 0.415, + 0.581 + ], + "angle": 0, + "content": "(d) MAE usage" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.591, + 0.47, + 0.647 + ], + "angle": 0, + "content": "Table 5. Ablation studies of MAE branch. (a) Results of different mask ratios. (b) Results of coefficient decay strategies. (c) The training data that MAE are applied to. (d) The usage of MAE (as a branch or as an independent pretraining stage)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.673, + 0.468, + 0.884 + ], + "angle": 0, + "content": "notes that we drop the MAE branch after a certain teaching epoch. \"No decay\" receives sub-optimal result for the MAE branch benefits less when more pseudo labels are provided, thus its influence to the overall objective should be lowered at later stage of training. Table 5(c) illustrates that MAE is sensitive to domain shift of the input data. Training with target features receives better performance on target evaluation compared with the inputs that consist source images. Table 5(d) compares the result of MAE branch with the pretrain-finetune paradigm which is commonly used in pretraining tasks, indicating that in DAOD, pretraining on relatively small dataset with distinctive domain characteristics leads the model to over-fit on reconstruction task. MRT use a customised MAE branch to overcome this issue." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.886, + 0.469, + 0.901 + ], + "angle": 0, + "content": "Analysis of Selective Retraining: Utilizing selective" + }, + { + "type": "image", + "bbox": [ + 0.501, + 0.224, + 0.707, + 0.32 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.532, + 0.321, + 0.658, + 0.333 + ], + "angle": 0, + "content": "(a) Retrained module" + }, + { + "type": "image", + "bbox": [ + 0.721, + 0.224, + 0.885, + 0.321 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.718, + 0.321, + 0.885, + 0.333 + ], + "angle": 0, + "content": "(b) Re-initialization weights" + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.343, + 0.892, + 0.399 + ], + "angle": 0, + "content": "Table 6. Ablation studies of selective retraining. (a) Results of different retrained modules (tick for retrained). \"Bac.\", \"Enc.\" and \"Dec.\" denotes backbone, encoder and decoder respectively. (b) Results of different re-initialization weights." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.425, + 0.892, + 0.591 + ], + "angle": 0, + "content": "retraining, we periodically re-initialize some components of the model while keeping other components as enhanced parts. In teacher-student framework, we do not re-initialize teacher as has been discussed in Section 4.3. For the student model, we choose the retrained modules through experimental results. Table 6(a) shows that keeping the decoder updated and retraining backbone and decoder gets the best performance. For the re-initialization weights, Table 6(b) shows that MAE refined weights receives the best performance. Further discussion on the selective retraining mechanism can be seen in Appendix." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.607, + 0.619, + 0.623 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.633, + 0.892, + 0.799 + ], + "angle": 0, + "content": "In this paper, we propose a novel Masked Retraining Teacher-student framework (MRT) on domain adaptive object detection task. Our customized design of masked autoencoder branch helps the student model better capture target domain characteristics and gain knowledge from limited amount of pseudo boxes, and the selective retraining mechanism allows the model to jump out of the local optimum biased to the incorrect pseudo labels. Experiments on three benchmarks confirmed the effectiveness of our model. Extensive ablation experiments demonstrate that every design helps to improve domain adaptation ability of the model." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.815, + 0.688, + 0.832 + ], + "angle": 0, + "content": "7. Acknowledgements" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.9 + ], + "angle": 0, + "content": "This work was supported by National Natural Science Foundation of China (61925201,62132001), Zhejiang Lab (NO.2022NB0AB05) and CCF-Tencent Open Research Fund." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19046" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.47, + 0.157 + ], + "angle": 0, + "content": "[1] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. Beit: Bert pre-training of image transformers. arXiv preprint arXiv:2106.08254, 2021.3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.16, + 0.471, + 0.229 + ], + "angle": 0, + "content": "[2] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, et al. Language models are few-shot learners. Advances in neural information processing systems, 33:1877-1901, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.232, + 0.471, + 0.299 + ], + "angle": 0, + "content": "[3] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In European conference on computer vision, pages 213-229. Springer, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.302, + 0.471, + 0.372 + ], + "angle": 0, + "content": "[4] Chaoqi Chen, Zebiao Zheng, Yue Huang, Xinghao Ding, and Yizhou Yu. I3net: Implicit instance-invariant network for adapting one-stage object detectors. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12576-12585, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.374, + 0.47, + 0.456 + ], + "angle": 0, + "content": "[5] Meilin Chen, Weijie Chen, Shicai Yang, Jie Song, Xin chao Wang, Lei Zhang, Yunfeng Yan, Donglian Qi, Yueting Zhuang, Di Xie, et al. Learning domain adaptive object detection with probabilistic teacher. In International Conference on Machine Learning, pages 3040-3055. PMLR, 2022. 1, 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.46, + 0.47, + 0.514 + ], + "angle": 0, + "content": "[6] Mark Chen, Alec Radford, Rewon Child, Jeffrey Wu, Heewoo Jun, David Luan, and Ilya Sutskever. Generative pretraining from pixels. In International conference on machine learning, pages 1691-1703. PMLR, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.517, + 0.471, + 0.572 + ], + "angle": 0, + "content": "[7] Qingchao Chen and Yang Liu. Structure-aware feature fusion for unsupervised domain adaptation. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 10567-10574, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.574, + 0.47, + 0.643 + ], + "angle": 0, + "content": "[8] Qingchao Chen, Yang Liu, Zhaowen Wang, Ian Wassell, and Kevin Chetty. Re-weighted adversarial adaptation network for unsupervised domain adaptation. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 7976-7985, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.646, + 0.47, + 0.713 + ], + "angle": 0, + "content": "[9] Yuhua Chen, Wen Li, Christos Sakaridis, Dengxin Dai, and Luc Van Gool. Domain adaptive faster r-cnn for object detection in the wild. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3339-3348, 2018. 1, 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.717, + 0.47, + 0.8 + ], + "angle": 0, + "content": "[10] Marius Cordts, Mohamed Omran, Sebastian Ramos, Timo Rehfeld, Markus Enzweiler, Rodrigo Benenson, Uwe Franke, Stefan Roth, and Bernt Schiele. The cityscapes dataset for semantic urban scene understanding. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3213-3223, 2016. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.803, + 0.47, + 0.87 + ], + "angle": 0, + "content": "[11] Zhigang Dai, Bolun Cai, Yugeng Lin, and Junying Chen. Up-detr: Unsupervised pre-training for object detection with transformers. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 1601-1610, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[12] Jinhong Deng, Wen Li, Yuhua Chen, and Lixin Duan. Unbiased mean teacher for cross-domain object detection. In" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.133 + ], + "angle": 0, + "content": "Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4091-4101, 2021. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.136, + 0.892, + 0.232 + ], + "angle": 0, + "content": "[13] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers), pages 4171–4186, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.234, + 0.892, + 0.317 + ], + "angle": 0, + "content": "[14] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2020. 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.319, + 0.892, + 0.36 + ], + "angle": 0, + "content": "[15] Yaroslav Ganin and Victor Lempitsky. Unsupervised domain adaptation by backpropagation. In International conference on machine learning, pages 1180-1189. PMLR, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.362, + 0.892, + 0.403 + ], + "angle": 0, + "content": "[16] Golnaz Ghiasi, Tsung-Yi Lin, and Quoc V Le. Dropblock: A regularization method for convolutional networks. Advances in neural information processing systems, 31, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.406, + 0.892, + 0.459 + ], + "angle": 0, + "content": "[17] Kaixiong Gong, Shuang Li, Shugang Li, Rui Zhang, Chi Harold Liu, and Qiang Chen. Improving transferability for domain adaptive detection transformers. arXiv preprint arXiv:2204.14195, 2022. 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.462, + 0.892, + 0.53 + ], + "angle": 0, + "content": "[18] Song Han, Jeff Pool, Sharan Narang, Huizi Mao, Enhao Gong, Shijian Tang, Erich Elsen, Peter Vajda, Manohar Paluri, John Tran, et al. Dsd: Dense-sparse-dense training for deep neural networks. arXiv preprint arXiv:1607.04381, 2016. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.533, + 0.892, + 0.601 + ], + "angle": 0, + "content": "[19] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollar, and Ross Girshick. Masked autoencoders are scalable vision learners. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 16000-16009, 2022. 2, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.604, + 0.892, + 0.686 + ], + "angle": 0, + "content": "[20] Mengzhe He, Yali Wang, Jiaxi Wu, Yiru Wang, Hanqing Li, Bo Li, Weihao Gan, Wei Wu, and Yu Qiao. Cross domain object detection by target-perceived dual branch distillation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9570-9580, 2022. 1, 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.688, + 0.892, + 0.744 + ], + "angle": 0, + "content": "[21] Zhenwei He and Lei Zhang. Multi-adversarial faster-rcnn for unrestricted object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6668–6677, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.746, + 0.892, + 0.813 + ], + "angle": 0, + "content": "[22] Cheng-Chun Hsu, Yi-Hsuan Tsai, Yen-Yu Lin, and Ming-Hsuan Yang. Every pixel matters: Center-aware feature alignment for domain adaptive object detector. In European Conference on Computer Vision, pages 733-748. Springer, 2020. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.816, + 0.892, + 0.87 + ], + "angle": 0, + "content": "[23] Gao Huang, Yixuan Li, Geoff Pleiss, Zhuang Liu, John E Hopcroft, and Kilian Q Weinberger. Snapshot ensembles: Train 1, get m for free. arXiv preprint arXiv:1704.00109, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.873, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[24] Wei-Jie Huang, Yu-Lin Lu, Shih-Yao Lin, Yusheng Xie, and Yen-Yu Lin. Aqt: Adversarial query transformers for domain" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19047" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "adaptive object detection. In 31st International Joint Conference on Artificial Intelligence, IJCAI 2022, pages 972-979. International Joint Conferences on Artificial Intelligence, 2022. 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.149, + 0.47, + 0.203 + ], + "angle": 0, + "content": "[25] Junguang Jiang, Baixu Chen, Jianmin Wang, and Mingsheng Long. Decoupled adaptation for cross-domain object detection. In International Conference on Learning Representations, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.205, + 0.471, + 0.272 + ], + "angle": 0, + "content": "[26] Matthew Johnson-Roberson, Charles Barto, Rounak Mehta, Sharath Nittur Sridhar, Karl Rosaen, and Ram Vasudevan. Driving in the matrix: Can virtual worlds replace human-generated annotations for real world tasks? arXiv preprint arXiv:1610.01983, 2016. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.274, + 0.471, + 0.355 + ], + "angle": 0, + "content": "[27] Taekyung Kim, Minki Jeong, Seunghyeon Kim, Seokeon Choi, and Changick Kim. Diversify and match: A domain adaptive representation learning paradigm for object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12456-12465, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.357, + 0.471, + 0.425 + ], + "angle": 0, + "content": "[28] Wuyang Li, Xinyu Liu, and Yixuan Yuan. Sigma: Semantic-complete graph matching for domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5291-5300, 2022. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.428, + 0.471, + 0.509 + ], + "angle": 0, + "content": "[29] Yu-Jhe Li, Xiaoliang Dai, Chih-Yao Ma, Yen-Cheng Liu, Kan Chen, Bichen Wu, Zijian He, Kris Kitani, and Peter Vajda. Cross-domain adaptive teacher for object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7581-7590, 2022. 1, 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.511, + 0.471, + 0.58 + ], + "angle": 0, + "content": "[30] Tsung-Yi Lin, Piotr Dólar, Ross Girshick, Kaiming He, Bharath Hariharan, and Serge Belongie. Feature pyramid networks for object detection. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2117-2125, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.581, + 0.471, + 0.635 + ], + "angle": 0, + "content": "[31] Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dólár. Focal loss for dense object detection. In Proceedings of the IEEE international conference on computer vision, pages 2980-2988, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.637, + 0.471, + 0.704 + ], + "angle": 0, + "content": "[32] Wei Liu, Dragomir Anguelov, Dumitru Erhan, Christian Szegedy, Scott Reed, Cheng-Yang Fu, and Alexander C Berg. Ssd: Single shot multibox detector. In European conference on computer vision, pages 21-37. Springer, 2016. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.706, + 0.471, + 0.774 + ], + "angle": 0, + "content": "[33] Muhammad Akhtar Munir, Muhammad Haris Khan, M Sarfraz, and Mohsen Ali. Ssal: Synergizing between selftraining and adversarial learning for domain adaptive object detection. Advances in Neural Information Processing Systems, 34:22770-22782, 2021. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.776, + 0.471, + 0.845 + ], + "angle": 0, + "content": "[34] Mengxue Qu, Yu Wu, Wu Liu, Qiqi Gong, Xiaodan Liang, Olga Russakovsky, Yao Zhao, and Yunchao Wei. Siri: A simple selective retraining mechanism for transformer-based visual grounding. In European Conference on Computer Vision, pages 546-562. Springer, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.471, + 0.9 + ], + "angle": 0, + "content": "[35] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. Advances in neural information processing systems, 28, 2015. 1, 2, 6, 7" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.176 + ], + "angle": 0, + "content": "[36] Farzaneh Rezaeanaran, Rakshith Shetty, Rahaf Aljundi, Daniel Olmeda Reino, Shanshan Zhang, and Bernt Schiele. Seeking similarities over differences: Similarity-based domain alignment for adaptive object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 9204-9213, 2021. 2, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.178, + 0.892, + 0.233 + ], + "angle": 0, + "content": "[37] Christos Sakaridis, Dengxin Dai, and Luc Van Gool. Semantic foggy scene understanding with synthetic data. International Journal of Computer Vision, 126(9):973-992, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.235, + 0.894, + 0.289 + ], + "angle": 0, + "content": "[38] Nitish Srivastava, Geoffrey Hinton, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. Dropout: a simple way to prevent neural networks from overfitting. The journal of machine learning research, 15(1):1929-1958, 2014. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.291, + 0.892, + 0.36 + ], + "angle": 0, + "content": "[39] Kun Tian, Chenghao Zhang, Ying Wang, Shiming Xiang, and Chunhong Pan. Knowledge mining and transferring for domain adaptive object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 9133–9142, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.362, + 0.892, + 0.418 + ], + "angle": 0, + "content": "[40] Zhi Tian, Chunhua Shen, Hao Chen, and Tong He. Fcos: Fully convolutional one-stage object detection. In Proceedings of the IEEE/CVF international conference on computer vision, pages 9627-9636, 2019. 1, 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.42, + 0.892, + 0.475 + ], + "angle": 0, + "content": "[41] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. Videomae: Masked autoencoders are data-efficient learners for self-supervised video pre-training. arXiv preprint arXiv:2203.12602, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.477, + 0.892, + 0.545 + ], + "angle": 0, + "content": "[42] Pascal Vincent, Hugo Larochelle, Yoshua Bengio, and Pierre-Antoine Manzagol. Extracting and composing robust features with denoising autoencoders. In Proceedings of the 25th international conference on Machine learning, pages 1096-1103, 2008. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.548, + 0.892, + 0.63 + ], + "angle": 0, + "content": "[43] Vibashan Vs, Vikram Gupta, Poojan Oza, Vishwanath A Sindagi, and Vishal M Patel. Mega-cda: Memory guided attention for category-aware unsupervised domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4516-4526, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.632, + 0.892, + 0.702 + ], + "angle": 0, + "content": "[44] Wen Wang, Yang Cao, Jing Zhang, Fengxiang He, Zheng-Jun Zha, Yonggang Wen, and Dacheng Tao. Exploring sequence feature alignment for domain adaptive detection transformers. In Proceedings of the 29th ACM International Conference on Multimedia, pages 1730-1738, 2021. 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.704, + 0.892, + 0.771 + ], + "angle": 0, + "content": "[45] Chang-Dong Xu, Xing-Ran Zhao, Xin Jin, and Xiu-Shen Wei. Exploring categorical regularization for domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11724-11733, 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.774, + 0.892, + 0.843 + ], + "angle": 0, + "content": "[46] Minghao Xu, Hang Wang, Bingbing Ni, Qi Tian, and Wenjun Zhang. Cross-domain detection via graph-induced prototype alignment. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12355-12364, 2020. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.845, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[47] Fisher Yu, Haofeng Chen, Xin Wang, Wenqi Xian, Yingying Chen, Fangchen Liu, Vashisht Madhavan, and Trevor Darell. Bdd100k: A diverse driving dataset for heterogeneous multitask learning. In Proceedings of the IEEE/CVF con" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19048" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.093, + 0.469, + 0.119 + ], + "angle": 0, + "content": "ference on computer vision and pattern recognition, pages 2636-2645, 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.47, + 0.19 + ], + "angle": 0, + "content": "[48] Jinze Yu, Jiaming Liu, Xiaobao Wei, Haoyi Zhou, Yohei Nakata, Denis Gudovskiy, Tomoyuki Okuno, Jianxin Li, Kurt Keutzer, and Shanghang Zhang. Cross-domain object detection with mean-teacher transformer. arXiv preprint arXiv:2205.01643, 2022. 1, 2, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.192, + 0.469, + 0.233 + ], + "angle": 0, + "content": "[49] Dan Zhang, Jingjing Li, Lin Xiong, Lan Lin, Mao Ye, and Shangming Yang. Cycle-consistent domain adaptive faster rcnn. IEEE Access, 7:123903-123911, 2019. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.235, + 0.469, + 0.29 + ], + "angle": 0, + "content": "[50] Liang Zhao and Limin Wang. Task-specific inconsistency alignment for domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14217-14226, 2022. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.292, + 0.469, + 0.347 + ], + "angle": 0, + "content": "[51] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable detr: Deformable transformers for end-to-end object detection. In International Conference on Learning Representations, 2020. 1, 2, 3, 6, 7" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.093, + 0.47, + 0.347 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.956 + ], + "angle": 0, + "content": "19049" + } + ] +] \ No newline at end of file diff --git a/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/5a41b22e-9755-4ada-9123-4e6d5ca57c32_origin.pdf b/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/5a41b22e-9755-4ada-9123-4e6d5ca57c32_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..d8a8407c8cfb68957e8f811ba94ec761afb00ca3 --- /dev/null +++ b/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/5a41b22e-9755-4ada-9123-4e6d5ca57c32_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:4332089110a35cabd68629f704003ddd7558a17edba254ba8da0819000f73d83 +size 2709592 diff --git a/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/full.md b/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/full.md new file mode 100644 index 0000000000000000000000000000000000000000..d5eeb4981917ae8e5de91ae53da9b6c03407ff00 --- /dev/null +++ b/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/full.md @@ -0,0 +1,329 @@ +# Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection + +Zijing Zhao $^{1}$ Sitong Wei $^{1}$ Qingchao Chen $^{2}$ Dehui Li $^{3}$ Yifan Yang $^{3}$ Yuxin Peng $^{1}$ Yang Liu $^{1*}$ $^{1}$ Wangxuan Institute of Computer Technology, Peking University + $^{2}$ National Institute of Health Data Science, Peking University + $^{3}$ Tencent Intelligent Mobility +zijingzhao@stu.pku.edu.cn {weisitong, qingchao.chen, pengyuxin, yangliu}@oku.edu.cn +{dehuili, lvanyang}@tencent.com + +# Abstract + +Domain adaptive Object Detection (DAOD) leverages a labeled domain (source) to learn an object detector generalizing to a novel domain without annotation (target). Recent advances use a teacher-student framework, i.e., a student model is supervised by the pseudo labels from a teacher model. Though great success, they suffer from the limited number of pseudo boxes with incorrect predictions caused by the domain shift, misleading the student model to get sub-optimal results. To mitigate this problem, we propose Masked Retraining Teacher-student framework (MRT) which leverages masked autoencoder and selective retraining mechanism on detection transformer. Specifically, we present a customized design of masked autoencoder branch, masking the multi-scale feature maps of target images and reconstructing features by the encoder of the student model and an auxiliary decoder. This helps the student model capture target domain characteristics and become a more data-efficient learner to gain knowledge from the limited number of pseudo boxes. Furthermore, we adopt selective retraining mechanism, periodically re-initializing certain parts of the student parameters with masked autoencoder refined weights to allow the model to jump out of the local optimum biased to the incorrect pseudo labels. Experimental results on three DAOD benchmarks demonstrate the effectiveness of our method. Code can be found at https://github.com/JeremyZhao1998/MRT-release. + +# 1. Introduction + +Object detection has a wide range of real-world application scenarios, and has been deeply studied in computer vision researches. CNN-based [35, 32, 40] and transformer-based [3, 51] detectors have shown great success in challenging benchmarks. However, they suffer from domain + +![](images/c6b35c3c697150246b1e1eb509c76f1920244abde7a71cf8db2ff3f1b30ea2f3.jpg) +(a) mAP under limited boxes +Figure 1. (a) Performance under limited number of box annotations. We adopt MAE in training target images with ground truth labels, but manually reduce the amount of bounding boxes. MAE boosts the performance by a large margin under limited boxes. (b) Performance of Category "bicycle" during training. The performance declines rapidly due to the local optimum caused by incorrect pseudo boxes. With the help of retraining (every 40 epochs), the model is able to jump out of the local optimum. + +![](images/94cc22a39ad05ec3161251866f1c032ea8da4c01ee079e011ad09499cebe3164.jpg) +(b) Category AP during training + +shift where there is an obvious distribution gap between the pretraining data and the deployed environment. + +To mitigate the performance drop caused by domain shift without extra annotation, unsupervised domain adaptation (UDA) has been studied in classification, segmentation and object detection tasks, where the model is trained on a labeled source domain and an unlabeled target domain, and is expected to generalize well on the target domain. As a branch of UDA, unsupervised domain adaptive object detection (DAOD) researches [9, 49, 29, 48] utilize numerous techniques such as adversarial alignment, image-to-image translation, GNNs and mean teacher training, widely improving domain adaptation performance of object detectors. + +Among these approaches, [29, 48, 5, 20] use a teacher-student framework where a teacher model produces pseudo labels of the unlabeled target images to supervise a student model, and has achieved significant performance gains. + +However, the teaching process faces the challenge of low-quality pseudo labels in which there are limited number of pseudo boxes and incorrect predictions caused by the domain shift. Under such framework, pseudo labels are selected from outputs of the teacher model by a threshold of confidence scores. Selecting large amounts of pseudo labels with lower threshold brings too many incorrect predictions, degrading the performance, while with higher threshold, the limited number of pseudo boxes provides sub-optimal supervision. Blue bars of Figure 1(a) shows that even supervised by ground truth labels without domain shift, the performance drops significantly when the amount of box annotations are reduced. Anyhow, incorrect predictions always exist, leading the model to get stuck at the local optimum. As is shown in Figure 1(b), in the later stage of training, performance of some categories declines rapidly (the blue curve) due to the growing number of incorrect pseudo boxes. Though [29] utilizes adversarial alignment and weak-strong augmentation to minimize the false positive ratio of pseudo labels, they ignore the sub-optimal supervision of the limited number of pseudo boxes, and the impact of incorrect pseudo labels which always exist. + +To address this issue, we propose Masked Retraining Teacher-student framework (MRT) which is built on the baseline of adaptive teacher-student framework for Deformable DETR[51] detector, leveraging masked autoencoder (MAE) and selective retraining mechanism. + +Unlike pretraining MAEs[19, 41] which leverage large-scale training data under a pretrain-finetune paradigm, we present a customized design of MAE branch, randomly masking portions of multi-scale feature maps of the target images and reconstructing the missing features from their contexts by the encoder of the student model and an auxiliary decoder, simultaneously with the detection loss. As a self-supervised task on target images, MAE leads the transformer encoder to gain more intimate knowledge of the target domain from the limited number of pseudo boxes. Empirically, we observe that MAE helps the model encode better features, improving the performance under any amount of supervision and achieving larger gains when fewer box annotations are provided, as is shown in Figure 1(a). + +Furthermore, as the student model is sensitive to the pseudo label noise, we adopt a simple yet effective selective retraining mechanism. Specifically, we periodically re-initialize certain parts of the student parameters to allow the model to jump out of the local optimum biased to the incorrect pseudo labels. Unlike existing retraining approaches [18, 34] that ignore the quality of re-initialization weights, we re-initialize the student model with MAE refined weights to avoid low-quality student weights to impact the teacher model through EMA. In teacher-student framework, an enhanced teacher model helps the student recover rapidly after the re-initialization. As is shown in the orange + +curve of Figure 1(b), retraining recovers the performance that has been corrupted by noisy pseudo labels. + +We summarize the contribution of this paper as follow: 1) We propose a novel Masked Retraining Teacher-student framework(MRT) for training domain adaptive detection transformers, which is built on the adaptive teacher-student framework baseline and overcomes the problem of low-quality pseudo labels. 2) To the best of our knowledge, we are the first to present that masked autoencoder is a data-efficient domain adapter which helps the model better capture domain characteristics, and the first to adopt selective retraining mechanism in teacher-student framework to help the model jump out of local optimums. 3) Our method outperforms existing approaches by a large margin and achieves state-of-the-art on three DAOD benchmarks. + +# 2. Related Work + +Object detection: Object detection has been deeply studied in computer vision. CNN-based methods[35, 30, 31] present region proposals networks and achieve outstanding performance. One-stage detectors without region proposals [32, 40] simplify the structure and perform faster. Recently, transformer-based models [3, 51] are also developed in object detection, exploring token-wise dependencies for context modeling. These methods all focus on supervised learning, while we aim to generalize the model to a novel domain without extra annotations. In this work, we employ Deformable DETR[51] as the detector due to its simplified one-stage structure and the flexible transfer-learning ability of the transformer architecture. + +Domain adaptive object detection: Domain adaptive object detection (DAOD) is raised to overcome the domain shift problem in object detection. As a pioneer work of DAOD, [9] investigates adversarial feature alignment for Faster R-CNN. Following [9], [21, 8, 27, 7, 4, 36, 46] apply different aspects of feature alignments, and [44, 24, 17] elaborately design alignments for transformer architectures. Numerous techniques such as image-to-image translation[49], graph reasoning[28, 48] and pseudo label self-training[12, 29, 48] have also been studied for DAOD. Among existing approaches, methods utilizing teacher-student framework achieve leading position in experimental performances. [29] utilizes adversarial alignment and weak-strong augmentation to minimize the false positive ratio of pseudo labels. [20] reduces domain shift by incorporating target object knowledge through self-distillation. [5] employs uncertainty-guided self-training to promote both classification and localization adaptations. Though great success, they ignore the low-quality pseudo labels which contains limited number of bounding boxes and incorrect predictions. We build our method on the baseline of teacher-student framework with adversarial alignment, introducing MAE and selective retraining to overcome such problem. + +Masked autoencoders: Autoencoding is a classical representation learning method, utilizing an encoder to map the input to a latent representation and a decoder to reconstruct the input. Denoising autoencoders (DAE)[42] corrupt the input signal and learn to reconstruct the original, uncorrupted signal. Recently, DAE methods are widely used in large-scale pretraining tasks in both language models [13, 2] and vision models [6, 14, 1], holding out a portion of the input and train models to predict the missing content. The influential MAE[19] randomly masks image patches with a high portion and reconstruct the missing pixels by an asymmetric architecture to pretrain a vision transformer that generalize well in downstream tasks. [41] explores MAE in video pretraining, raising the point that MAE is a data-efficient learner and domain shift is an important factor during pretraining. [11] employs attention mask for DETR decoder as an unsupervised pretraining task. However, these works all focus on pretraining transformer-based backbones with all accessible data to generalize to downstream tasks, without considering domain shift. We empirically observe that feeding MAE with inputs from mismatched domain provides sub-optimal results. Thus, we apply MAE only on target images for domain adaptation, guiding the encoder to better capture target domain characteristics. + +Overcoming local optimums: Optimizing neural networks faces the challenge of local optimums. Regularization methods such as Dropout[38] and DropBlock[16] try to avoid the model from over-fitting or getting trapped in local minimums by introducing randomness. [23] introduces cyclic learning rate, but is inapplicable for transformer-based models. Recent studies show that retraining is a simple yet effective way for transformers. [18] proposes DSD retraining with reference to model pruning to avoid overfitting to noisy data, and [34] proposes selective retraining mechanism for visual grounding transformers to converge to better minimums. To the best of our knowledge, we are the first to adopt retraining in teacher-student framework to overcome the impact of incorrect pseudo labels. Under such framework, quality of the re-initialization weights become significant, which has not been studied in existing retraining approaches, since the teacher model may be influenced by the re-initialized student weights to provide sub-optimal pseudo labels. We re-initializing the student parameters with MAE refined weights to avoid the problem. + +# 3. Problem Formulation and Baseline + +# 3.1. Problem Formulation + +We first review the problem formulation of unsupervised DAOD. Given a labeled source dataset $D_{s} = \{(x_{s}^{i},y_{s}^{i})\}_{i = 1}^{N_{s}}$ sized $N_{s}$ and an unlabeled target dataset $D_{t} = \{x_{t}^{i}\}_{i = 1}^{N_{t}}$ sized $N_{t}$ , where $x$ denotes an image and $y = (b,c)$ represents an annotation for object detection including bounding + +box $b$ and the corresponding category $c$ , we train a domain adaptive detector with both $D_{s}$ and $D_{t}$ , and evaluate the detection performance on data in the target domain. + +# 3.2. Adaptive Teacher-student Baseline Revisited + +Recent advances [46, 48] use a teacher-student framework combined with adversarial alignment and achieve SOTA. Our method is built on the adaptive teacher-student framework as baseline. We revisit the baseline as follow. + +Teacher-student framework: A teacher model $T$ and a student model $S$ share the same structure of backbone, encoder and decoder. The teacher takes a weakly augmented target image $x_{t}$ and produces pseudo labels $(\hat{b}_{t},\hat{c}_{t})$ . The student takes both source and target images which are strongly augmented. Supervised loss $\mathcal{L}_{sup}$ is calculated on $x_{s}$ with their ground truth labels same as [51]: + +$$ +\mathcal {L} _ {s u p} = \mathcal {L} _ {b o x} ^ {S} \left(x _ {s}, y _ {s}\right) + \mathcal {L} _ {g i o u} ^ {S} \left(x _ {s}, y _ {s}\right) + \mathcal {L} _ {c l s} ^ {S} \left(x _ {s}, y _ {s}\right) \tag {1} +$$ + +while $x_{t}$ receive supervision from pseudo labels, but only in classification task following [46] as unsupervised loss: + +$$ +\mathcal {L} _ {u n s u p} = \mathcal {L} _ {c l s} ^ {S} \left(x _ {t}, \hat {b} _ {t}, \hat {c} _ {t}\right) \tag {2} +$$ + +The teacher is only updated by Exponential Moving Average (EMA) from the student without gradient accumulation: + +$$ +\theta_ {t} \leftarrow \alpha \theta_ {t} + (1 - \alpha) \theta_ {s} \tag {3} +$$ + +where $\theta_{t}$ and $\theta_{s}$ denotes the model parameters of teacher and student respectively, and $\alpha$ is a hyper-parameter. + +Discriminators for adversarial alignment: Domain discriminators $D$ are placed after certain components to predict the domain label of the features, updated by BCE loss. On Deformable DETR detector, we set discriminators for the backbone, encoder and decoder to provide global level, token-wise multi-scale feature level and instance level alignment respectively, and $\mathcal{L}_{dis}$ denotes their weighted sum. The adversarial optimization objective is formulated: + +$$ +\mathcal {L} _ {a d v} = \max _ {S} \min _ {D} \mathcal {L} _ {d i s} \tag {4} +$$ + +where $S, D$ denotes the student and discriminators respectively. Gradient Reverse Layers(GRL)[15] is adopted for min-max optimization. Overall objective of the student is: + +$$ +\mathcal {L} _ {\text {t e a c h}} = \mathcal {L} _ {\sup } + \mathcal {L} _ {\operatorname {a d v}} + \lambda_ {\text {u n s u p}} \mathcal {L} _ {\text {u n s u p}} \tag {5} +$$ + +where $\lambda_{unsup}$ is the hyper-parameter, while the teacher is updated only by EMA which has been discussed. Before teaching process, the model will first be trained with $\mathcal{L}_{sup}$ using annotated source data $D_{s}$ , and both teacher and student model will be initialized with such parameters. + +The adaptive teacher-student baseline on Deformable DETR outperforms most existing DAOD approaches. However, the problem of low-quality pseudo labels still exist, + +![](images/ba04201101bba07153fef6bdb30cb84382b1023b51669b6386ed3025fd9c9fea.jpg) +Figure 2. Overview Masked Retraining Teacher-student framework(MRT). The adaptive teacher-student baseline consists of a teacher model which takes weakly-augmented target images and produces pseudo labels, and a student model which takes strongly augmented source and target images, supervised by ground truth labels and pseudo labels respectively. Adversarial alignment are applied on backbone, encoder and decoder. Our proposed MAE branch masks feature maps of target images, and and reconstructs the feature by student encoder and an auxiliary decoder. Our proposed selective retraining mechanism periodically re-initialize certain parts of the student parameters as highlighted. The teacher model is updated only by EMA from the student model. Empirically, we use the teacher model at inference time. + +leading the model to sub-optimal results, as has been shown in Figure 1. Our proposed method overcomes this issue by introducing MAE branch and selective retraining mechanism which will be elaborated in the following section. + +# 4. Proposed Method + +# 4.1. Method Overview + +Our proposed method can be overviewed in Figure 2, which is built on the adaptive teacher-student baseline discussed in Section 3.2. We propose a customized design of masked autoencoder(MAE) branch for student model, randomly masking a portion of the multi-scale feature maps of the target images, feeding them into the encoder, and introducing an auxiliary decoder to reconstruct the missing features from their contexts. As a self-supervised task on target images, MAE leads the transformer encoder to gain more intimate knowledge of the target domain, thus helps the model better capture target domain characteristics and boosts the performance when the amount of pseudo boxes are limited. Employing selective retraining mechanism, we periodically re-initialize parts of the student parameters with the MAE refined weights, as is illustrated in Figure 2 with marked units, while the teacher model is continually updated via exponential moving average (EMA) from the student model. In this way, the teacher model continually produces relatively high-quality pseudo labels without be + +ing corrupted by re-initialized low-quality student weights, and the student model is allowed to jump out of the local optimum biased to the incorrect pseudo boxes. Selecting pseudo labels from outputs of the teacher is also important. A fixed confidence threshold is often used, but is unaware of the imbalance sample class distribution and the training period. We propose a dynamic threshold strategy to set different thresholds for each category dynamically during training, selecting appropriate amount of pseudo boxes. + +# 4.2. Masked Autoencoder Branch + +We propose a customized design of MAE branch for the student model to better capture target domain characteristic as a self-supervised domain adapter, and to effectively gain knowledge from the limited number of high-quality pseudo boxes. The multi-scale feature maps of target images will be masked and fed into the student encoder, and reconstructed by an auxiliary decoder. The masking and reconstructing processes are elaborated as follows. + +Feature masking: Unlike ViT [14] backbone which directly takes image patches as the input, the Deformable DETR encoder takes the multi-scale feature maps $\{z_{i}\in$ $\mathbb{R}^{C_i\times H_i\times W_i}\}_{i = 1}^K$ which are projected from the output of the backbone, where $K$ denotes the number of scales. We randomly generate masking $\{m_i\in \{0,1\}^{H_i\times W_i}\}_{i = 1}^K$ for every scale of the feature maps with the same masking ratio. The deformable attention relies on the spatial structure of the + +feature maps to generate reference points and sampling locations that is used to choose points on the value matrix to perform sparse attention, so the spatial structure of the input cannot be serialized. As a result, we set the masked portion of the corresponding value matrix to zero in deformable attention to perform zero-masking, unlike [19] that only sends unmasked patches as a serialized input to ViT. + +Reconstruction: The encoder takes the masked feature maps, and further encodes the feature maps with deformable attention. On the output features of the encoder, we fill the masked portion with a shared mask query $q_{m}$ and send them to an auxiliary MAE decoder $S_{m}$ to reconstruct the feature map. Following [19], we adopt an asymmetric lightweight decoder. Since the last layer of the backbone outputs, i.e., $z_{K}$ contains all the semantic information, we only reconstruct it to speed up convergence and reduce computation. The last layer of MAE decoder is a linear projection whose output channels equals to the channels of $z_{K}$ . Eventually, we compute mean square error (MSE) between the reconstructed and original features, but only on the masked portion, formulated as: + +$$ +\hat {z} _ {K} = S _ {m} \left(S _ {e} \left(\operatorname {m a s k} \left(m, x _ {t}\right)\right), q _ {m}\right) \tag {6} +$$ + +$$ +\mathcal {L} _ {\text {m a s k}} = \mathcal {L} _ {\text {M S E}} \left(\operatorname {m a s k} \left(m _ {K}, z _ {K} ^ {\prime}\right), \operatorname {m a s k} \left(m _ {K}, z _ {K}\right)\right) \tag {7} +$$ + +where $S_{e}, S_{m}, q_{m}$ denotes the encoder of student model, the auxiliary MAE decoder and the mask query respectively. + +Training data: Note that although student model takes both source and target images, we employ MAE only on target images, since DAOD aims to train the detector to perform better on the unlabeled target domain, and applying MAE with source images leads the model to generate source domain features with sub-optimal performance. Employing MAE on target images helps the student encoder to gain more intimate knowledge of the target domain, and boosts performance when high-quality pseudo labels are limited. We apply MAE on student model instead of teacher, for it is the student model who suffers from sub-optimal supervision of the limited pseudo boxes. Besides, the teacher model is not supervised by any detection loss. Employing MAE on the teacher model creates an encoder that is incompatible with the decoder and detection head, thus is unable to provide meaningful pseudo labels. + +Training strategy: We train the MAE branch and detection loss simultaneously instead of following the pretrainfinetune paradigm, since pretraining leads the model to over-fit to reconstruction task due to the relatively small dataset with distinctive domain characteristics. Before the teaching process, we first train the model with $\mathcal{L}_{sup}$ in Equation(1) together with $\mathcal{L}_{mask}$ in Equation(7) to produce an enhanced initialization $\theta_{mask}$ for teaching, and as a refined re-initialization for selective retraining. The overall objective of student model in teaching process is: + +$$ +\mathcal {L} = \mathcal {L} _ {\text {t e a c h}} + \lambda_ {\text {m a s k}} \mathcal {L} _ {\text {m a s k}} \tag {8} +$$ + +where $\mathcal{L}_{\text {teach }}$ has been formulated in Equation(5), and $\lambda_{mask}$ is the coefficient of $\mathcal{L}_{mask}$ in Equation(7). As the teaching process continues, adequate amount of pseudo boxes will be produced, and the influence of $\mathcal{L}_{mask}$ should be lowered to avoid the encoder over-fitting to reconstruction task. As a result, We decay $\lambda_{mask}$ as teaching continues. More details will be discussed in Section 5.4. + +# 4.3. Selective Retraining Mechanism + +The transformer-based models tend to over-fit without large-scale training data, especially when noisy annotations are included. Here in our case, pseudo labels always contain noise since they are provided by the updating teacher model instead of ground truths. As is shown in Figure 1(b), in later stage of the teaching process, performance of certain categories are severely influenced due to the over-fitting to the incorrect pseudo labels. Worse still, since the teacher model is continually updated via EMA from student model, it could also by affected and produces even worse pseudo labels. We adopt selective retraining mechanism on student branch to help student model jump out of local optimums biased to incorrect pseudo labels. + +To be specific, during teaching period, we continually update the teacher model via EMA without retraining it, but periodically re-initialize parts of the student model with the MAE refined parameters $\theta_{mask}$ which has been discussed in Section 4.2. Though $\theta_{mask}$ do not contain detection knowledge, its target domain encoding ability has not been corrupted by noisy pseudo labels. After re-initialization, the retrained components are allowed to leave the local optimum and can be guided by the fixed parts which can be regarded as better trained, and by an enhanced teacher which is continually updated. We do not retrain the teacher model since re-initialization cause a sudden drop of pseudo label quality, thus deteriorate the teaching process. We re-initialize the student model with MAE refined weights $\theta_{mask}$ rather than source-only trained weights or random weights for a quicker recovery, preventing its negative influence to teacher via EMA. We choose the retrained components by experimental studies. We try to perform reinitialization on different parts of the student model and choose the setting with best performance in which the decoder is kept while the backbone and encoder are retrained. More details will be discussed in Section 5.4. + +# 4.4. Dynamic Threshold + +Existing teacher-student frameworks on DAOD set a fixed confidence threshold to select pseudo labels from outputs of the teacher model. However, we observe in experiments that as the teaching process continues, the predicted confidence scores tend to rise, introducing too many pseudo labels which contain much more incorrect labels. Besides, fixed threshold for every category ignores the category dis + +
MethodDetectorpersonridercartruckbustrainmcyclebicyclemAP
FasterRCNN[35](Source)FRCNN26.938.235.618.332.49.625.828.626.9
DA-Faster[9]FRCNN29.240.443.419.738.328.523.732.732.0
UMT[12]FRCNN33.046.748.634.156.546.830.437.341.7
TIA[50]FRCNN34.846.349.731.152.148.637.738.142.3
D-adapt[25]FRCNN40.847.157.533.546.941.433.643.043.0
SIGMA[28]FRCNN44.043.960.331.650.451.531.740.644.2
\(AT^1\) [29]FRCNN43.754.162.331.954.449.335.247.947.4
TDD[20]FRCNN50.753.768.235.153.045.138.949.149.2
PT[5]FRCNN40.248.863.430.751.830.635.444.542.7
FCOS[40] (Source)FCOS36.936.344.118.629.38.420.331.928.2
EPM[22]FCOS44.246.658.524.845.229.128.634.639.0
SSAL[33]FCOS45.147.459.424.550.025.726.038.739.6
Def DETR[51] (Source)Def DETR37.739.144.217.226.85.821.635.528.5
SFA[44]Def DETR46.548.662.625.146.229.428.344.041.3
MTTrans[48]Def DETR47.749.965.225.845.933.832.646.543.4
\(O^2\text{net}\)[17]Def DETR48.751.563.631.147.647.838.045.946.8
AQT[24]Def DETR49.352.364.427.753.746.536.046.447.1
MRT(Ours)Def DETR52.851.768.735.958.154.541.047.151.2
+ +Table 1. Results of Cityscapes to Foggy Cityscapes(0.02). "FRCNN" denotes Faster R-CNN and "Def DETR" denotes Deformable DETR. + +tribution of samples. To address this issue, we initialize the thresholds for each category by a same value, and dynamically update them based on the predicted confidence scores of the source domain instances. In this way, the thresholds for each category could be updated differently. More details and discussion of the rationality and effectiveness of this method can be found in Appendix. + +# 5. Experiments + +# 5.1. Datasets + +Following existing DAOD approaches [44, 48, 17, 24], we evaluate our method on the following benchmarks. + +Cityscapes to Foggy Cityscapes: Cityscapes[10] is collected from urban scenes containing 2,975 images for training and 500 images for validation. Foggy Cityscapes[37] is constructed by a fog synthesis algorithm from Cityscapes. We use Cityscapes as source domain and Foggy Cityscapes with highest fog density(0.02) as target domain. + +Cityscapes to BDD100k-daytime: BDD100k[47] is a large-scale driving dataset. Its daytime subset containing 36,728 training images and 5,258 validation images is commonly used in DAOD. We used Cityscapes as source domain and BDD100k-daytime as target domain. + +Sim10k to Cityscapes(car): Sim10k[26] is a synthetic dataset from GTA game engine containing 10,000 images. We use Sim10k as source domain and "car" instances in Cityscapes as target domain. + +# 5.2. Implementation Details + +We use Deformable DETR [51] as our base detector. For loss coefficients, we set $\lambda_{unsup} = 1.0$ and initial $\lambda_{mask} = 1.0$ . For the discriminators, the coefficients of backbone, encoder and decoder is set 0.3, 1.0, 1.0 respectively. We set the weight smooth parameter $\alpha = 0.9996$ in EMA. For dynamic threshold, we initialize the thresholds for each category by 0.3. For MAE branch, we use a 2-layer asymmetric decoder and a mask ratio of 0.8. We optimize the network by Adam optimizer with initial learning rate $2 \times 10^{-4}$ and batch size 8. The data augmentation methods include random horizontal flip for weak augmentation, and randomly color jittering, grayscale and Gaussian blurring for strong augmentations. Algorithms are implemented by PyTorch. More implementation details which differ between benchmarks can be seen in Appendix. + +# 5.3. Comparing with Other Methods + +We compare our proposed MRT with other methods on the three benchmarks mentioned above. Our proposed MRT outperforms previous methods, and achieves significant improvements compared with DETR-based methods. As shown in Table 1, for categories with fewer instances (i.e. "truck") in Cityscapes to Foggy Cityscapes, MRT performs much better, as the data-efficient MAE branch boost the performance. For confusing categories (i.e. "bicycle" and "motorcycle"), MRT has a significant performance gain with the help of selective retraining mechanism. As shown in Table 2, on Cityscapes to BDD100k-daytime where the class distribution of target dataset is largely different from + +
MethodDetectorpersonridercartruckbusmcyclebicyclemAP
FasterRCNN[35](Source)FRCNN28.825.444.117.916.113.922.424.1
DA-Faster[9]FRCNN28.927.444.219.118.014.222.424.9
ICR-CCR-SW[45]FRCNN32.829.345.822.720.614.925.527.4
FCOS[40] (Source)FCOS38.624.854.517.216.315.018.326.4
EPM[22]FCOS39.626.855.818.819.114.520.127.8
Def DETR[51] (Source)Def DETR38.926.755.215.719.710.816.226.2
SFA[44]Def DETR40.227.657.519.123.415.419.228.9
AQT[24]Def DETR38.233.058.417.318.416.923.529.4
O2net[17]Def DETR40.431.258.620.425.014.922.730.5
MTTrans[48]Def DETR44.130.161.525.126.917.723.032.6
MRT(Ours)Def DETR48.430.963.724.725.520.222.633.7
+ +Table 2. Results of Cityscapes to BDD100k-daytime. + +
MethodDetectorcarAP
Faster R-CNN(Source)[35]FRCNN39.4
DA-Faster[9]FRCNN41.9
MeGA-CDA[43]FRCNN44.8
GPA[45]FRCNN47.6
ViSGA[36]FRCNN49.3
KTNet[39]FRCNN50.7
PT[5]FRCNN55.1
FCOS(Source)[40]FCOS42.5
EPM[22]FCOS47.3
SSAL[33]FCOS51.8
Deformable DETR(Source)[51]Def DETR47.4
SFA[44]Def DETR52.6
AQT[24]Def DETR53.4
O2net[17]Def DETR54.1
MTTrans [29]Def DETR57.9
MRT(Ours)Def DETR62.0
+ +source, MRT still achieves leading. As shown in Table 3, on Sim10k to Cityscapes(car), MRT outperforms previous SOTAs, indicating that our proposed method stays effective under larger domain gap. + +# 5.4. Ablation Study and Analysis + +In this section, we provide ablation study and analysis of our proposed approaches. All experiments are conducted on Cityscapes to Foggy Cityscapes. + +Quantitative Ablation Study: The effect of proposed modules are presented in Table 4, from which we can observe: 1) Introducing MAE branch without teacher-student framework (line 2) shows a significant improvement compared with source-only trained model, indicating that MAE is a data-efficient domain adapter. 2) MAE branch, selective retraining and dynamic filter respectively improves the performance by a large margin (line 4-6) when independently + +Table 3. Results of Sim10k to Cityscapes(car). + +
SourceBaselineDTRetrainMAEmAP
✓28.5
✓✓35.8
✓✓44.9
✓✓✓45.5
✓✓✓✓48.3
✓✓✓✓48.1
✓✓✓✓✓51.2
+ +Table 4. Ablation studies of proposed modules on Cityscapes to Foggy Cityscapes. "Source" denotes the source-only trained model. "Baseline" denotes the adaptive teacher-student baseline. "DT", "Retrain" and "MAE" denotes proposed dynamic threshold, selective retraining and masked autoencoder branch, respectively. + +used, illustrating their effectiveness. 3) Retraining combining with MAE refined re-initialization (line 7) further improves the performance, indicating that our proposed design maximizes the advantages of both modules. + +Qualitative visualization analysis: We provide qualitative visualization analysis of pseudo labels and feature distributions. Figure 3 shows the selected pseudo labels. From Figure 3(b) to 3(c), MAE guide the model to provide more pseudo labels, and from Figure 3(c) to 3(d), selective retraining filters out incorrect pseudo labels and predicts closer to ground truth. Figure 4 visualizes the features of two domains by t-SNE. MAE branch provides a much better initialization compared to source-only trained model, and our proposed MRT further bridges the domain gap. More visualization figures can be seen in Appendix. + +Analysis of MAE branch: Table 5 shows the detailed results of MAE ablation. Table 5(a) indicates that relatively high mask ratio yields a nontrivial and meaningful self-supervisory task. Table 5(b) explores the decay strategy of MAE coefficient $\lambda_{mask}$ . "no decay" denotes the MAE loss continually exists with fixed $\lambda_{mask}$ . "linear" denotes $\lambda_{mask}$ decays linearly during teaching process. "hard" de + +![](images/b01752e886155a4070d7863d647a4929ac0c7ea70d534070a14663140a36fca7.jpg) +(a) Source-only + +![](images/4f73a368f397709af7b0f7ff42a4c66dc7298b67340a1ab04aa6c41722b0cf02.jpg) +(b) Baseline + +![](images/e5b27c2e05be8f98f50b4787986508537ae0184c2710a1639e325b92ea28d02e.jpg) +(c) MRT w/o Retrain + +![](images/ee9677c7894658429c18d35d43299888f100bf44ce74e7227941f507e3b9ecb9.jpg) +(d) MRT (ours) + +![](images/57023cc84755db92dd6adc3a942445ac8401f730ac4e9c8dc0be2a3e6ed174ce.jpg) +(e) Ground truth + +![](images/22fca1e0697ec39f238ed943d27fa6311fb9c0bbbcaebfa4a9b0fa4f7ff1e4bf.jpg) +(a) Source-only +Figure 4. Qualitative ablation: feature visualization of the two domains on Cityscapes to Foggy Cityscapes by t-SNE. The blue and orange points denote source and target features respectively. + +![](images/1db509e0492abc3c2cc537a65627d028180f11520c8943e31e57047fe32c6c9e.jpg) +(b) Source+MAE + +![](images/d305f8924a52b93b4ca583c2c65c024e111bcc8ec8f887a9386c8669eb95f13a.jpg) +(c) MRT (ours) + +
Mask ratiomAP
0.547.1
0.848.3
0.946.8
+ +(a) Mask ratio + +
StrategymAP
No decay47.9
Linear48.2
Hard48.3
+ +(b) Coefficient decay + +
Training datamAP
Source44.5
Source & Target47.0
Target48.3
+ +(c) MAE Training data + +
MAE usagemAP
w/o MAE44.9
Pretrain42.7
MAE branch48.3
+ +(d) MAE usage + +Table 5. Ablation studies of MAE branch. (a) Results of different mask ratios. (b) Results of coefficient decay strategies. (c) The training data that MAE are applied to. (d) The usage of MAE (as a branch or as an independent pretraining stage). + +notes that we drop the MAE branch after a certain teaching epoch. "No decay" receives sub-optimal result for the MAE branch benefits less when more pseudo labels are provided, thus its influence to the overall objective should be lowered at later stage of training. Table 5(c) illustrates that MAE is sensitive to domain shift of the input data. Training with target features receives better performance on target evaluation compared with the inputs that consist source images. Table 5(d) compares the result of MAE branch with the pretrain-finetune paradigm which is commonly used in pretraining tasks, indicating that in DAOD, pretraining on relatively small dataset with distinctive domain characteristics leads the model to over-fit on reconstruction task. MRT use a customised MAE branch to overcome this issue. + +Analysis of Selective Retraining: Utilizing selective + +![](images/39019c2f8f5e6f3ae5d4db0714b424771cb8bea191ce62ac97d7ffbcbb05d4ad.jpg) +Figure 3. Qualitative ablation: pseudo labels for Foggy Cityscapes. "Baseline" denotes the adaptive teacher-student baseline. +(a) Retrained module + +![](images/0fd8840883226dacfd2c8648769411cf6a12f831285c1cbccc081491ce431c34.jpg) +(b) Re-initialization weights +Table 6. Ablation studies of selective retraining. (a) Results of different retrained modules (tick for retrained). "Bac.", "Enc." and "Dec." denotes backbone, encoder and decoder respectively. (b) Results of different re-initialization weights. + +retraining, we periodically re-initialize some components of the model while keeping other components as enhanced parts. In teacher-student framework, we do not re-initialize teacher as has been discussed in Section 4.3. For the student model, we choose the retrained modules through experimental results. Table 6(a) shows that keeping the decoder updated and retraining backbone and decoder gets the best performance. For the re-initialization weights, Table 6(b) shows that MAE refined weights receives the best performance. Further discussion on the selective retraining mechanism can be seen in Appendix. + +# 6. Conclusion + +In this paper, we propose a novel Masked Retraining Teacher-student framework (MRT) on domain adaptive object detection task. Our customized design of masked autoencoder branch helps the student model better capture target domain characteristics and gain knowledge from limited amount of pseudo boxes, and the selective retraining mechanism allows the model to jump out of the local optimum biased to the incorrect pseudo labels. Experiments on three benchmarks confirmed the effectiveness of our model. Extensive ablation experiments demonstrate that every design helps to improve domain adaptation ability of the model. + +# 7. Acknowledgements + +This work was supported by National Natural Science Foundation of China (61925201,62132001), Zhejiang Lab (NO.2022NB0AB05) and CCF-Tencent Open Research Fund. + +# References + +[1] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. Beit: Bert pre-training of image transformers. arXiv preprint arXiv:2106.08254, 2021.3 +[2] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, et al. Language models are few-shot learners. Advances in neural information processing systems, 33:1877-1901, 2020. 3 +[3] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In European conference on computer vision, pages 213-229. Springer, 2020. 1, 2 +[4] Chaoqi Chen, Zebiao Zheng, Yue Huang, Xinghao Ding, and Yizhou Yu. I3net: Implicit instance-invariant network for adapting one-stage object detectors. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12576-12585, 2021. 2 +[5] Meilin Chen, Weijie Chen, Shicai Yang, Jie Song, Xin chao Wang, Lei Zhang, Yunfeng Yan, Donglian Qi, Yueting Zhuang, Di Xie, et al. Learning domain adaptive object detection with probabilistic teacher. In International Conference on Machine Learning, pages 3040-3055. PMLR, 2022. 1, 2, 6, 7 +[6] Mark Chen, Alec Radford, Rewon Child, Jeffrey Wu, Heewoo Jun, David Luan, and Ilya Sutskever. Generative pretraining from pixels. In International conference on machine learning, pages 1691-1703. PMLR, 2020. 3 +[7] Qingchao Chen and Yang Liu. Structure-aware feature fusion for unsupervised domain adaptation. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 10567-10574, 2020. 2 +[8] Qingchao Chen, Yang Liu, Zhaowen Wang, Ian Wassell, and Kevin Chetty. Re-weighted adversarial adaptation network for unsupervised domain adaptation. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 7976-7985, 2018. 2 +[9] Yuhua Chen, Wen Li, Christos Sakaridis, Dengxin Dai, and Luc Van Gool. Domain adaptive faster r-cnn for object detection in the wild. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3339-3348, 2018. 1, 2, 6, 7 +[10] Marius Cordts, Mohamed Omran, Sebastian Ramos, Timo Rehfeld, Markus Enzweiler, Rodrigo Benenson, Uwe Franke, Stefan Roth, and Bernt Schiele. The cityscapes dataset for semantic urban scene understanding. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3213-3223, 2016. 6 +[11] Zhigang Dai, Bolun Cai, Yugeng Lin, and Junying Chen. Up-detr: Unsupervised pre-training for object detection with transformers. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 1601-1610, 2021. 3 +[12] Jinhong Deng, Wen Li, Yuhua Chen, and Lixin Duan. Unbiased mean teacher for cross-domain object detection. In + +Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4091-4101, 2021. 2, 6 +[13] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers), pages 4171–4186, 2019. 3 +[14] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2020. 3, 4 +[15] Yaroslav Ganin and Victor Lempitsky. Unsupervised domain adaptation by backpropagation. In International conference on machine learning, pages 1180-1189. PMLR, 2015. 3 +[16] Golnaz Ghiasi, Tsung-Yi Lin, and Quoc V Le. Dropblock: A regularization method for convolutional networks. Advances in neural information processing systems, 31, 2018. 3 +[17] Kaixiong Gong, Shuang Li, Shugang Li, Rui Zhang, Chi Harold Liu, and Qiang Chen. Improving transferability for domain adaptive detection transformers. arXiv preprint arXiv:2204.14195, 2022. 2, 6, 7 +[18] Song Han, Jeff Pool, Sharan Narang, Huizi Mao, Enhao Gong, Shijian Tang, Erich Elsen, Peter Vajda, Manohar Paluri, John Tran, et al. Dsd: Dense-sparse-dense training for deep neural networks. arXiv preprint arXiv:1607.04381, 2016. 2, 3 +[19] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollar, and Ross Girshick. Masked autoencoders are scalable vision learners. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 16000-16009, 2022. 2, 3, 5 +[20] Mengzhe He, Yali Wang, Jiaxi Wu, Yiru Wang, Hanqing Li, Bo Li, Weihao Gan, Wei Wu, and Yu Qiao. Cross domain object detection by target-perceived dual branch distillation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9570-9580, 2022. 1, 2, 6 +[21] Zhenwei He and Lei Zhang. Multi-adversarial faster-rcnn for unrestricted object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6668–6677, 2019. 2 +[22] Cheng-Chun Hsu, Yi-Hsuan Tsai, Yen-Yu Lin, and Ming-Hsuan Yang. Every pixel matters: Center-aware feature alignment for domain adaptive object detector. In European Conference on Computer Vision, pages 733-748. Springer, 2020. 6, 7 +[23] Gao Huang, Yixuan Li, Geoff Pleiss, Zhuang Liu, John E Hopcroft, and Kilian Q Weinberger. Snapshot ensembles: Train 1, get m for free. arXiv preprint arXiv:1704.00109, 2017. 3 +[24] Wei-Jie Huang, Yu-Lin Lu, Shih-Yao Lin, Yusheng Xie, and Yen-Yu Lin. Aqt: Adversarial query transformers for domain + +adaptive object detection. In 31st International Joint Conference on Artificial Intelligence, IJCAI 2022, pages 972-979. International Joint Conferences on Artificial Intelligence, 2022. 2, 6, 7 +[25] Junguang Jiang, Baixu Chen, Jianmin Wang, and Mingsheng Long. Decoupled adaptation for cross-domain object detection. In International Conference on Learning Representations, 2021. 6 +[26] Matthew Johnson-Roberson, Charles Barto, Rounak Mehta, Sharath Nittur Sridhar, Karl Rosaen, and Ram Vasudevan. Driving in the matrix: Can virtual worlds replace human-generated annotations for real world tasks? arXiv preprint arXiv:1610.01983, 2016. 6 +[27] Taekyung Kim, Minki Jeong, Seunghyeon Kim, Seokeon Choi, and Changick Kim. Diversify and match: A domain adaptive representation learning paradigm for object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12456-12465, 2019. 2 +[28] Wuyang Li, Xinyu Liu, and Yixuan Yuan. Sigma: Semantic-complete graph matching for domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5291-5300, 2022. 2, 6 +[29] Yu-Jhe Li, Xiaoliang Dai, Chih-Yao Ma, Yen-Cheng Liu, Kan Chen, Bichen Wu, Zijian He, Kris Kitani, and Peter Vajda. Cross-domain adaptive teacher for object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7581-7590, 2022. 1, 2, 6, 7 +[30] Tsung-Yi Lin, Piotr Dólar, Ross Girshick, Kaiming He, Bharath Hariharan, and Serge Belongie. Feature pyramid networks for object detection. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2117-2125, 2017. 2 +[31] Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dólár. Focal loss for dense object detection. In Proceedings of the IEEE international conference on computer vision, pages 2980-2988, 2017. 2 +[32] Wei Liu, Dragomir Anguelov, Dumitru Erhan, Christian Szegedy, Scott Reed, Cheng-Yang Fu, and Alexander C Berg. Ssd: Single shot multibox detector. In European conference on computer vision, pages 21-37. Springer, 2016. 1, 2 +[33] Muhammad Akhtar Munir, Muhammad Haris Khan, M Sarfraz, and Mohsen Ali. Ssal: Synergizing between selftraining and adversarial learning for domain adaptive object detection. Advances in Neural Information Processing Systems, 34:22770-22782, 2021. 6, 7 +[34] Mengxue Qu, Yu Wu, Wu Liu, Qiqi Gong, Xiaodan Liang, Olga Russakovsky, Yao Zhao, and Yunchao Wei. Siri: A simple selective retraining mechanism for transformer-based visual grounding. In European Conference on Computer Vision, pages 546-562. Springer, 2022. 2, 3 +[35] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. Advances in neural information processing systems, 28, 2015. 1, 2, 6, 7 + +[36] Farzaneh Rezaeanaran, Rakshith Shetty, Rahaf Aljundi, Daniel Olmeda Reino, Shanshan Zhang, and Bernt Schiele. Seeking similarities over differences: Similarity-based domain alignment for adaptive object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 9204-9213, 2021. 2, 7 +[37] Christos Sakaridis, Dengxin Dai, and Luc Van Gool. Semantic foggy scene understanding with synthetic data. International Journal of Computer Vision, 126(9):973-992, 2018. 6 +[38] Nitish Srivastava, Geoffrey Hinton, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. Dropout: a simple way to prevent neural networks from overfitting. The journal of machine learning research, 15(1):1929-1958, 2014. 3 +[39] Kun Tian, Chenghao Zhang, Ying Wang, Shiming Xiang, and Chunhong Pan. Knowledge mining and transferring for domain adaptive object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 9133–9142, 2021. 7 +[40] Zhi Tian, Chunhua Shen, Hao Chen, and Tong He. Fcos: Fully convolutional one-stage object detection. In Proceedings of the IEEE/CVF international conference on computer vision, pages 9627-9636, 2019. 1, 2, 6, 7 +[41] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. Videomae: Masked autoencoders are data-efficient learners for self-supervised video pre-training. arXiv preprint arXiv:2203.12602, 2022. 2, 3 +[42] Pascal Vincent, Hugo Larochelle, Yoshua Bengio, and Pierre-Antoine Manzagol. Extracting and composing robust features with denoising autoencoders. In Proceedings of the 25th international conference on Machine learning, pages 1096-1103, 2008. 3 +[43] Vibashan Vs, Vikram Gupta, Poojan Oza, Vishwanath A Sindagi, and Vishal M Patel. Mega-cda: Memory guided attention for category-aware unsupervised domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4516-4526, 2021. 7 +[44] Wen Wang, Yang Cao, Jing Zhang, Fengxiang He, Zheng-Jun Zha, Yonggang Wen, and Dacheng Tao. Exploring sequence feature alignment for domain adaptive detection transformers. In Proceedings of the 29th ACM International Conference on Multimedia, pages 1730-1738, 2021. 2, 6, 7 +[45] Chang-Dong Xu, Xing-Ran Zhao, Xin Jin, and Xiu-Shen Wei. Exploring categorical regularization for domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11724-11733, 2020. 7 +[46] Minghao Xu, Hang Wang, Bingbing Ni, Qi Tian, and Wenjun Zhang. Cross-domain detection via graph-induced prototype alignment. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12355-12364, 2020. 2, 3 +[47] Fisher Yu, Haofeng Chen, Xin Wang, Wenqi Xian, Yingying Chen, Fangchen Liu, Vashisht Madhavan, and Trevor Darell. Bdd100k: A diverse driving dataset for heterogeneous multitask learning. In Proceedings of the IEEE/CVF con + +ference on computer vision and pattern recognition, pages 2636-2645, 2020. 6 +[48] Jinze Yu, Jiaming Liu, Xiaobao Wei, Haoyi Zhou, Yohei Nakata, Denis Gudovskiy, Tomoyuki Okuno, Jianxin Li, Kurt Keutzer, and Shanghang Zhang. Cross-domain object detection with mean-teacher transformer. arXiv preprint arXiv:2205.01643, 2022. 1, 2, 3, 6, 7 +[49] Dan Zhang, Jingjing Li, Lin Xiong, Lan Lin, Mao Ye, and Shangming Yang. Cycle-consistent domain adaptive faster rcnn. IEEE Access, 7:123903-123911, 2019. 1, 2 +[50] Liang Zhao and Limin Wang. Task-specific inconsistency alignment for domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14217-14226, 2022. 6 +[51] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable detr: Deformable transformers for end-to-end object detection. In International Conference on Learning Representations, 2020. 1, 2, 3, 6, 7 \ No newline at end of file diff --git a/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/images.zip b/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..3419d598b51c89cadea14341340df0e21cac6ec3 --- /dev/null +++ b/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:56194d148a42099cf1f3c708036ac551f7993a2cd0c9a836dc72a5ab9853c1c0 +size 567526 diff --git a/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/layout.json b/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..7eb84dc08f94f6498df91970275fdb749a5d3e57 --- /dev/null +++ b/2023/Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection/layout.json @@ -0,0 +1,8404 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 135, + 103, + 459, + 139 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 135, + 103, + 459, + 139 + ], + "spans": [ + { + "bbox": [ + 135, + 103, + 459, + 139 + ], + "type": "text", + "content": "Masked Retraining Teacher-Student Framework for Domain Adaptive Object Detection" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "spans": [ + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "text", + "content": "Zijing Zhao" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "text", + "content": " Sitong Wei" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "text", + "content": " Qingchao Chen" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "text", + "content": " Dehui Li" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "text", + "content": " Yifan Yang" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "text", + "content": " Yuxin Peng" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "text", + "content": " Yang Liu" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "text", + "content": "Wangxuan Institute of Computer Technology, Peking University \n" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "text", + "content": "National Institute of Health Data Science, Peking University \n" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 52, + 159, + 547, + 232 + ], + "type": "text", + "content": "Tencent Intelligent Mobility \nzijingzhao@stu.pku.edu.cn {weisitong, qingchao.chen, pengyuxin, yangliu}@oku.edu.cn \n{dehuili, lvanyang}@tencent.com" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 258, + 192, + 272 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 258, + 192, + 272 + ], + "spans": [ + { + "bbox": [ + 143, + 258, + 192, + 272 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 284, + 290, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 284, + 290, + 594 + ], + "spans": [ + { + "bbox": [ + 47, + 284, + 290, + 594 + ], + "type": "text", + "content": "Domain adaptive Object Detection (DAOD) leverages a labeled domain (source) to learn an object detector generalizing to a novel domain without annotation (target). Recent advances use a teacher-student framework, i.e., a student model is supervised by the pseudo labels from a teacher model. Though great success, they suffer from the limited number of pseudo boxes with incorrect predictions caused by the domain shift, misleading the student model to get sub-optimal results. To mitigate this problem, we propose Masked Retraining Teacher-student framework (MRT) which leverages masked autoencoder and selective retraining mechanism on detection transformer. Specifically, we present a customized design of masked autoencoder branch, masking the multi-scale feature maps of target images and reconstructing features by the encoder of the student model and an auxiliary decoder. This helps the student model capture target domain characteristics and become a more data-efficient learner to gain knowledge from the limited number of pseudo boxes. Furthermore, we adopt selective retraining mechanism, periodically re-initializing certain parts of the student parameters with masked autoencoder refined weights to allow the model to jump out of the local optimum biased to the incorrect pseudo labels. Experimental results on three DAOD benchmarks demonstrate the effectiveness of our method. Code can be found at https://github.com/JeremyZhao1998/MRT-release." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 616, + 128, + 629 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 616, + 128, + 629 + ], + "spans": [ + { + "bbox": [ + 47, + 616, + 128, + 629 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 636, + 287, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 636, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 636, + 287, + 696 + ], + "type": "text", + "content": "Object detection has a wide range of real-world application scenarios, and has been deeply studied in computer vision researches. CNN-based [35, 32, 40] and transformer-based [3, 51] detectors have shown great success in challenging benchmarks. However, they suffer from domain" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 310, + 262, + 432, + 368 + ], + "blocks": [ + { + "bbox": [ + 310, + 262, + 432, + 368 + ], + "lines": [ + { + "bbox": [ + 310, + 262, + 432, + 368 + ], + "spans": [ + { + "bbox": [ + 310, + 262, + 432, + 368 + ], + "type": "image", + "image_path": "c6b35c3c697150246b1e1eb509c76f1920244abde7a71cf8db2ff3f1b30ea2f3.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 323, + 372, + 419, + 382 + ], + "lines": [ + { + "bbox": [ + 323, + 372, + 419, + 382 + ], + "spans": [ + { + "bbox": [ + 323, + 372, + 419, + 382 + ], + "type": "text", + "content": "(a) mAP under limited boxes" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 304, + 395, + 547, + 483 + ], + "lines": [ + { + "bbox": [ + 304, + 395, + 547, + 483 + ], + "spans": [ + { + "bbox": [ + 304, + 395, + 547, + 483 + ], + "type": "text", + "content": "Figure 1. (a) Performance under limited number of box annotations. We adopt MAE in training target images with ground truth labels, but manually reduce the amount of bounding boxes. MAE boosts the performance by a large margin under limited boxes. (b) Performance of Category \"bicycle\" during training. The performance declines rapidly due to the local optimum caused by incorrect pseudo boxes. With the help of retraining (every 40 epochs), the model is able to jump out of the local optimum." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 433, + 262, + 542, + 368 + ], + "blocks": [ + { + "bbox": [ + 433, + 262, + 542, + 368 + ], + "lines": [ + { + "bbox": [ + 433, + 262, + 542, + 368 + ], + "spans": [ + { + "bbox": [ + 433, + 262, + 542, + 368 + ], + "type": "image", + "image_path": "94cc22a39ad05ec3161251866f1c032ea8da4c01ee079e011ad09499cebe3164.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 435, + 372, + 541, + 383 + ], + "lines": [ + { + "bbox": [ + 435, + 372, + 541, + 383 + ], + "spans": [ + { + "bbox": [ + 435, + 372, + 541, + 383 + ], + "type": "text", + "content": "(b) Category AP during training" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 506, + 545, + 531 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 506, + 545, + 531 + ], + "spans": [ + { + "bbox": [ + 304, + 506, + 545, + 531 + ], + "type": "text", + "content": "shift where there is an obvious distribution gap between the pretraining data and the deployed environment." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 532, + 546, + 664 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 532, + 546, + 664 + ], + "spans": [ + { + "bbox": [ + 304, + 532, + 546, + 664 + ], + "type": "text", + "content": "To mitigate the performance drop caused by domain shift without extra annotation, unsupervised domain adaptation (UDA) has been studied in classification, segmentation and object detection tasks, where the model is trained on a labeled source domain and an unlabeled target domain, and is expected to generalize well on the target domain. As a branch of UDA, unsupervised domain adaptive object detection (DAOD) researches [9, 49, 29, 48] utilize numerous techniques such as adversarial alignment, image-to-image translation, GNNs and mean teacher training, widely improving domain adaptation performance of object detectors." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "type": "text", + "content": "Among these approaches, [29, 48, 5, 20] use a teacher-student framework where a teacher model produces pseudo labels of the unlabeled target images to supervise a student model, and has achieved significant performance gains." + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 703, + 135, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 703, + 135, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 703, + 135, + 712 + ], + "type": "text", + "content": "*Corresponding author" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19039" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 335 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 335 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 335 + ], + "type": "text", + "content": "However, the teaching process faces the challenge of low-quality pseudo labels in which there are limited number of pseudo boxes and incorrect predictions caused by the domain shift. Under such framework, pseudo labels are selected from outputs of the teacher model by a threshold of confidence scores. Selecting large amounts of pseudo labels with lower threshold brings too many incorrect predictions, degrading the performance, while with higher threshold, the limited number of pseudo boxes provides sub-optimal supervision. Blue bars of Figure 1(a) shows that even supervised by ground truth labels without domain shift, the performance drops significantly when the amount of box annotations are reduced. Anyhow, incorrect predictions always exist, leading the model to get stuck at the local optimum. As is shown in Figure 1(b), in the later stage of training, performance of some categories declines rapidly (the blue curve) due to the growing number of incorrect pseudo boxes. Though [29] utilizes adversarial alignment and weak-strong augmentation to minimize the false positive ratio of pseudo labels, they ignore the sub-optimal supervision of the limited number of pseudo boxes, and the impact of incorrect pseudo labels which always exist." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 337, + 288, + 397 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 337, + 288, + 397 + ], + "spans": [ + { + "bbox": [ + 47, + 337, + 288, + 397 + ], + "type": "text", + "content": "To address this issue, we propose Masked Retraining Teacher-student framework (MRT) which is built on the baseline of adaptive teacher-student framework for Deformable DETR[51] detector, leveraging masked autoencoder (MAE) and selective retraining mechanism." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 400, + 289, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 400, + 289, + 568 + ], + "spans": [ + { + "bbox": [ + 47, + 400, + 289, + 568 + ], + "type": "text", + "content": "Unlike pretraining MAEs[19, 41] which leverage large-scale training data under a pretrain-finetune paradigm, we present a customized design of MAE branch, randomly masking portions of multi-scale feature maps of the target images and reconstructing the missing features from their contexts by the encoder of the student model and an auxiliary decoder, simultaneously with the detection loss. As a self-supervised task on target images, MAE leads the transformer encoder to gain more intimate knowledge of the target domain from the limited number of pseudo boxes. Empirically, we observe that MAE helps the model encode better features, improving the performance under any amount of supervision and achieving larger gains when fewer box annotations are provided, as is shown in Figure 1(a)." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 570, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 570, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 570, + 289, + 715 + ], + "type": "text", + "content": "Furthermore, as the student model is sensitive to the pseudo label noise, we adopt a simple yet effective selective retraining mechanism. Specifically, we periodically re-initialize certain parts of the student parameters to allow the model to jump out of the local optimum biased to the incorrect pseudo labels. Unlike existing retraining approaches [18, 34] that ignore the quality of re-initialization weights, we re-initialize the student model with MAE refined weights to avoid low-quality student weights to impact the teacher model through EMA. In teacher-student framework, an enhanced teacher model helps the student recover rapidly after the re-initialization. As is shown in the orange" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 304, + 72, + 545, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 95 + ], + "type": "text", + "content": "curve of Figure 1(b), retraining recovers the performance that has been corrupted by noisy pseudo labels." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 96, + 547, + 252 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 96, + 547, + 252 + ], + "spans": [ + { + "bbox": [ + 304, + 96, + 547, + 252 + ], + "type": "text", + "content": "We summarize the contribution of this paper as follow: 1) We propose a novel Masked Retraining Teacher-student framework(MRT) for training domain adaptive detection transformers, which is built on the adaptive teacher-student framework baseline and overcomes the problem of low-quality pseudo labels. 2) To the best of our knowledge, we are the first to present that masked autoencoder is a data-efficient domain adapter which helps the model better capture domain characteristics, and the first to adopt selective retraining mechanism in teacher-student framework to help the model jump out of local optimums. 3) Our method outperforms existing approaches by a large margin and achieves state-of-the-art on three DAOD benchmarks." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 262, + 392, + 275 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 262, + 392, + 275 + ], + "spans": [ + { + "bbox": [ + 306, + 262, + 392, + 275 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 283, + 547, + 437 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 283, + 547, + 437 + ], + "spans": [ + { + "bbox": [ + 304, + 283, + 547, + 437 + ], + "type": "text", + "content": "Object detection: Object detection has been deeply studied in computer vision. CNN-based methods[35, 30, 31] present region proposals networks and achieve outstanding performance. One-stage detectors without region proposals [32, 40] simplify the structure and perform faster. Recently, transformer-based models [3, 51] are also developed in object detection, exploring token-wise dependencies for context modeling. These methods all focus on supervised learning, while we aim to generalize the model to a novel domain without extra annotations. In this work, we employ Deformable DETR[51] as the detector due to its simplified one-stage structure and the flexible transfer-learning ability of the transformer architecture." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 438, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 438, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 438, + 547, + 715 + ], + "type": "text", + "content": "Domain adaptive object detection: Domain adaptive object detection (DAOD) is raised to overcome the domain shift problem in object detection. As a pioneer work of DAOD, [9] investigates adversarial feature alignment for Faster R-CNN. Following [9], [21, 8, 27, 7, 4, 36, 46] apply different aspects of feature alignments, and [44, 24, 17] elaborately design alignments for transformer architectures. Numerous techniques such as image-to-image translation[49], graph reasoning[28, 48] and pseudo label self-training[12, 29, 48] have also been studied for DAOD. Among existing approaches, methods utilizing teacher-student framework achieve leading position in experimental performances. [29] utilizes adversarial alignment and weak-strong augmentation to minimize the false positive ratio of pseudo labels. [20] reduces domain shift by incorporating target object knowledge through self-distillation. [5] employs uncertainty-guided self-training to promote both classification and localization adaptations. Though great success, they ignore the low-quality pseudo labels which contains limited number of bounding boxes and incorrect predictions. We build our method on the baseline of teacher-student framework with adversarial alignment, introducing MAE and selective retraining to overcome such problem." + } + ] + } + ], + "index": 8 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "19040" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 360 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 360 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 360 + ], + "type": "text", + "content": "Masked autoencoders: Autoencoding is a classical representation learning method, utilizing an encoder to map the input to a latent representation and a decoder to reconstruct the input. Denoising autoencoders (DAE)[42] corrupt the input signal and learn to reconstruct the original, uncorrupted signal. Recently, DAE methods are widely used in large-scale pretraining tasks in both language models [13, 2] and vision models [6, 14, 1], holding out a portion of the input and train models to predict the missing content. The influential MAE[19] randomly masks image patches with a high portion and reconstruct the missing pixels by an asymmetric architecture to pretrain a vision transformer that generalize well in downstream tasks. [41] explores MAE in video pretraining, raising the point that MAE is a data-efficient learner and domain shift is an important factor during pretraining. [11] employs attention mask for DETR decoder as an unsupervised pretraining task. However, these works all focus on pretraining transformer-based backbones with all accessible data to generalize to downstream tasks, without considering domain shift. We empirically observe that feeding MAE with inputs from mismatched domain provides sub-optimal results. Thus, we apply MAE only on target images for domain adaptation, guiding the encoder to better capture target domain characteristics." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 360, + 289, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 360, + 289, + 601 + ], + "spans": [ + { + "bbox": [ + 47, + 360, + 289, + 601 + ], + "type": "text", + "content": "Overcoming local optimums: Optimizing neural networks faces the challenge of local optimums. Regularization methods such as Dropout[38] and DropBlock[16] try to avoid the model from over-fitting or getting trapped in local minimums by introducing randomness. [23] introduces cyclic learning rate, but is inapplicable for transformer-based models. Recent studies show that retraining is a simple yet effective way for transformers. [18] proposes DSD retraining with reference to model pruning to avoid overfitting to noisy data, and [34] proposes selective retraining mechanism for visual grounding transformers to converge to better minimums. To the best of our knowledge, we are the first to adopt retraining in teacher-student framework to overcome the impact of incorrect pseudo labels. Under such framework, quality of the re-initialization weights become significant, which has not been studied in existing retraining approaches, since the teacher model may be influenced by the re-initialized student weights to provide sub-optimal pseudo labels. We re-initializing the student parameters with MAE refined weights to avoid the problem." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 613, + 242, + 625 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 613, + 242, + 625 + ], + "spans": [ + { + "bbox": [ + 47, + 613, + 242, + 625 + ], + "type": "text", + "content": "3. Problem Formulation and Baseline" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 633, + 171, + 645 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 633, + 171, + 645 + ], + "spans": [ + { + "bbox": [ + 47, + 633, + 171, + 645 + ], + "type": "text", + "content": "3.1. Problem Formulation" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "text", + "content": "We first review the problem formulation of unsupervised DAOD. Given a labeled source dataset " + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "inline_equation", + "content": "D_{s} = \\{(x_{s}^{i},y_{s}^{i})\\}_{i = 1}^{N_{s}}" + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "text", + "content": " sized " + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "inline_equation", + "content": "N_{s}" + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "text", + "content": " and an unlabeled target dataset " + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "inline_equation", + "content": "D_{t} = \\{x_{t}^{i}\\}_{i = 1}^{N_{t}}" + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "text", + "content": " sized " + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "inline_equation", + "content": "N_{t}" + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "text", + "content": " denotes an image and " + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "inline_equation", + "content": "y = (b,c)" + }, + { + "bbox": [ + 47, + 652, + 287, + 715 + ], + "type": "text", + "content": " represents an annotation for object detection including bounding" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "text", + "content": "box " + }, + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "b" + }, + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "text", + "content": " and the corresponding category " + }, + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "c" + }, + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "text", + "content": ", we train a domain adaptive detector with both " + }, + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "D_{s}" + }, + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "D_{t}" + }, + { + "bbox": [ + 304, + 72, + 545, + 109 + ], + "type": "text", + "content": ", and evaluate the detection performance on data in the target domain." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 115, + 537, + 128 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 115, + 537, + 128 + ], + "spans": [ + { + "bbox": [ + 305, + 115, + 537, + 128 + ], + "type": "text", + "content": "3.2. Adaptive Teacher-student Baseline Revisited" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 133, + 545, + 180 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 133, + 545, + 180 + ], + "spans": [ + { + "bbox": [ + 304, + 133, + 545, + 180 + ], + "type": "text", + "content": "Recent advances [46, 48] use a teacher-student framework combined with adversarial alignment and achieve SOTA. Our method is built on the adaptive teacher-student framework as baseline. We revisit the baseline as follow." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "content": "Teacher-student framework: A teacher model " + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "content": " and a student model " + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "content": " share the same structure of backbone, encoder and decoder. The teacher takes a weakly augmented target image " + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "inline_equation", + "content": "x_{t}" + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "content": " and produces pseudo labels " + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "inline_equation", + "content": "(\\hat{b}_{t},\\hat{c}_{t})" + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "content": ". The student takes both source and target images which are strongly augmented. Supervised loss " + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{sup}" + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "content": " is calculated on " + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "inline_equation", + "content": "x_{s}" + }, + { + "bbox": [ + 304, + 182, + 545, + 266 + ], + "type": "text", + "content": " with their ground truth labels same as [51]:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 312, + 272, + 545, + 287 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 272, + 545, + 287 + ], + "spans": [ + { + "bbox": [ + 312, + 272, + 545, + 287 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {s u p} = \\mathcal {L} _ {b o x} ^ {S} \\left(x _ {s}, y _ {s}\\right) + \\mathcal {L} _ {g i o u} ^ {S} \\left(x _ {s}, y _ {s}\\right) + \\mathcal {L} _ {c l s} ^ {S} \\left(x _ {s}, y _ {s}\\right) \\tag {1}", + "image_path": "0ac2d67999c52216fd1bf44a7c78319ab27a3673f6750290d9cff0a6107dcabd.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 294, + 545, + 319 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 294, + 545, + 319 + ], + "spans": [ + { + "bbox": [ + 304, + 294, + 545, + 319 + ], + "type": "text", + "content": "while " + }, + { + "bbox": [ + 304, + 294, + 545, + 319 + ], + "type": "inline_equation", + "content": "x_{t}" + }, + { + "bbox": [ + 304, + 294, + 545, + 319 + ], + "type": "text", + "content": " receive supervision from pseudo labels, but only in classification task following [46] as unsupervised loss:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 373, + 325, + 545, + 340 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 373, + 325, + 545, + 340 + ], + "spans": [ + { + "bbox": [ + 373, + 325, + 545, + 340 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {u n s u p} = \\mathcal {L} _ {c l s} ^ {S} \\left(x _ {t}, \\hat {b} _ {t}, \\hat {c} _ {t}\\right) \\tag {2}", + "image_path": "5b9b3c28c78e2ed574415c13eb75a7ddcf13a711a12067cdcad73ed69007fdcf.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 347, + 545, + 372 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 347, + 545, + 372 + ], + "spans": [ + { + "bbox": [ + 304, + 347, + 545, + 372 + ], + "type": "text", + "content": "The teacher is only updated by Exponential Moving Average (EMA) from the student without gradient accumulation:" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 378, + 383, + 545, + 396 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 378, + 383, + 545, + 396 + ], + "spans": [ + { + "bbox": [ + 378, + 383, + 545, + 396 + ], + "type": "interline_equation", + "content": "\\theta_ {t} \\leftarrow \\alpha \\theta_ {t} + (1 - \\alpha) \\theta_ {s} \\tag {3}", + "image_path": "ceb40cd178f80ebbfdb5c0bf81a78299702c29c357d811a281a6d2b208e47d1c.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 400, + 545, + 424 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 400, + 545, + 424 + ], + "spans": [ + { + "bbox": [ + 304, + 400, + 545, + 424 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 400, + 545, + 424 + ], + "type": "inline_equation", + "content": "\\theta_{t}" + }, + { + "bbox": [ + 304, + 400, + 545, + 424 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 400, + 545, + 424 + ], + "type": "inline_equation", + "content": "\\theta_{s}" + }, + { + "bbox": [ + 304, + 400, + 545, + 424 + ], + "type": "text", + "content": " denotes the model parameters of teacher and student respectively, and " + }, + { + "bbox": [ + 304, + 400, + 545, + 424 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 400, + 545, + 424 + ], + "type": "text", + "content": " is a hyper-parameter." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 425, + 545, + 520 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 425, + 545, + 520 + ], + "spans": [ + { + "bbox": [ + 304, + 425, + 545, + 520 + ], + "type": "text", + "content": "Discriminators for adversarial alignment: Domain discriminators " + }, + { + "bbox": [ + 304, + 425, + 545, + 520 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 304, + 425, + 545, + 520 + ], + "type": "text", + "content": " are placed after certain components to predict the domain label of the features, updated by BCE loss. On Deformable DETR detector, we set discriminators for the backbone, encoder and decoder to provide global level, token-wise multi-scale feature level and instance level alignment respectively, and " + }, + { + "bbox": [ + 304, + 425, + 545, + 520 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{dis}" + }, + { + "bbox": [ + 304, + 425, + 545, + 520 + ], + "type": "text", + "content": " denotes their weighted sum. The adversarial optimization objective is formulated:" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 380, + 529, + 545, + 546 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 380, + 529, + 545, + 546 + ], + "spans": [ + { + "bbox": [ + 380, + 529, + 545, + 546 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {a d v} = \\max _ {S} \\min _ {D} \\mathcal {L} _ {d i s} \\tag {4}", + "image_path": "cb6e989a99741b3ecff7cdafdff3c44c149012b5e38f2ec128a4f930efa0af7b.jpg" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 552, + 545, + 589 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 552, + 545, + 589 + ], + "spans": [ + { + "bbox": [ + 304, + 552, + 545, + 589 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 552, + 545, + 589 + ], + "type": "inline_equation", + "content": "S, D" + }, + { + "bbox": [ + 304, + 552, + 545, + 589 + ], + "type": "text", + "content": " denotes the student and discriminators respectively. Gradient Reverse Layers(GRL)[15] is adopted for min-max optimization. Overall objective of the student is:" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 343, + 597, + 545, + 610 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 343, + 597, + 545, + 610 + ], + "spans": [ + { + "bbox": [ + 343, + 597, + 545, + 610 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {t e a c h}} = \\mathcal {L} _ {\\sup } + \\mathcal {L} _ {\\operatorname {a d v}} + \\lambda_ {\\text {u n s u p}} \\mathcal {L} _ {\\text {u n s u p}} \\tag {5}", + "image_path": "c41c4381eb710894834867d81722fdbfd8778973d86db2d2343c6ecd0e0e3b5f.jpg" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 618, + 545, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 618, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 304, + 618, + 545, + 677 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 618, + 545, + 677 + ], + "type": "inline_equation", + "content": "\\lambda_{unsup}" + }, + { + "bbox": [ + 304, + 618, + 545, + 677 + ], + "type": "text", + "content": " is the hyper-parameter, while the teacher is updated only by EMA which has been discussed. Before teaching process, the model will first be trained with " + }, + { + "bbox": [ + 304, + 618, + 545, + 677 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{sup}" + }, + { + "bbox": [ + 304, + 618, + 545, + 677 + ], + "type": "text", + "content": " using annotated source data " + }, + { + "bbox": [ + 304, + 618, + 545, + 677 + ], + "type": "inline_equation", + "content": "D_{s}" + }, + { + "bbox": [ + 304, + 618, + 545, + 677 + ], + "type": "text", + "content": ", and both teacher and student model will be initialized with such parameters." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 677, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 545, + 714 + ], + "type": "text", + "content": "The adaptive teacher-student baseline on Deformable DETR outperforms most existing DAOD approaches. However, the problem of low-quality pseudo labels still exist," + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19041" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 67, + 72, + 539, + 291 + ], + "blocks": [ + { + "bbox": [ + 67, + 72, + 539, + 291 + ], + "lines": [ + { + "bbox": [ + 67, + 72, + 539, + 291 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 539, + 291 + ], + "type": "image", + "image_path": "ba04201101bba07153fef6bdb30cb84382b1023b51669b6386ed3025fd9c9fea.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 295, + 547, + 363 + ], + "lines": [ + { + "bbox": [ + 46, + 295, + 547, + 363 + ], + "spans": [ + { + "bbox": [ + 46, + 295, + 547, + 363 + ], + "type": "text", + "content": "Figure 2. Overview Masked Retraining Teacher-student framework(MRT). The adaptive teacher-student baseline consists of a teacher model which takes weakly-augmented target images and produces pseudo labels, and a student model which takes strongly augmented source and target images, supervised by ground truth labels and pseudo labels respectively. Adversarial alignment are applied on backbone, encoder and decoder. Our proposed MAE branch masks feature maps of target images, and and reconstructs the feature by student encoder and an auxiliary decoder. Our proposed selective retraining mechanism periodically re-initialize certain parts of the student parameters as highlighted. The teacher model is updated only by EMA from the student model. Empirically, we use the teacher model at inference time." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 380, + 288, + 430 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 380, + 288, + 430 + ], + "spans": [ + { + "bbox": [ + 46, + 380, + 288, + 430 + ], + "type": "text", + "content": "leading the model to sub-optimal results, as has been shown in Figure 1. Our proposed method overcomes this issue by introducing MAE branch and selective retraining mechanism which will be elaborated in the following section." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 444, + 153, + 458 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 444, + 153, + 458 + ], + "spans": [ + { + "bbox": [ + 47, + 444, + 153, + 458 + ], + "type": "text", + "content": "4. Proposed Method" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 466, + 153, + 478 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 466, + 153, + 478 + ], + "spans": [ + { + "bbox": [ + 47, + 466, + 153, + 478 + ], + "type": "text", + "content": "4.1. Method Overview" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 486, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 486, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 486, + 289, + 715 + ], + "type": "text", + "content": "Our proposed method can be overviewed in Figure 2, which is built on the adaptive teacher-student baseline discussed in Section 3.2. We propose a customized design of masked autoencoder(MAE) branch for student model, randomly masking a portion of the multi-scale feature maps of the target images, feeding them into the encoder, and introducing an auxiliary decoder to reconstruct the missing features from their contexts. As a self-supervised task on target images, MAE leads the transformer encoder to gain more intimate knowledge of the target domain, thus helps the model better capture target domain characteristics and boosts the performance when the amount of pseudo boxes are limited. Employing selective retraining mechanism, we periodically re-initialize parts of the student parameters with the MAE refined weights, as is illustrated in Figure 2 with marked units, while the teacher model is continually updated via exponential moving average (EMA) from the student model. In this way, the teacher model continually produces relatively high-quality pseudo labels without be" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 380, + 545, + 490 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 380, + 545, + 490 + ], + "spans": [ + { + "bbox": [ + 304, + 380, + 545, + 490 + ], + "type": "text", + "content": "ing corrupted by re-initialized low-quality student weights, and the student model is allowed to jump out of the local optimum biased to the incorrect pseudo boxes. Selecting pseudo labels from outputs of the teacher is also important. A fixed confidence threshold is often used, but is unaware of the imbalance sample class distribution and the training period. We propose a dynamic threshold strategy to set different thresholds for each category dynamically during training, selecting appropriate amount of pseudo boxes." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 500, + 465, + 513 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 500, + 465, + 513 + ], + "spans": [ + { + "bbox": [ + 305, + 500, + 465, + 513 + ], + "type": "text", + "content": "4.2. Masked Autoencoder Branch" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 520, + 545, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 520, + 545, + 616 + ], + "spans": [ + { + "bbox": [ + 304, + 520, + 545, + 616 + ], + "type": "text", + "content": "We propose a customized design of MAE branch for the student model to better capture target domain characteristic as a self-supervised domain adapter, and to effectively gain knowledge from the limited number of high-quality pseudo boxes. The multi-scale feature maps of target images will be masked and fed into the student encoder, and reconstructed by an auxiliary decoder. The masking and reconstructing processes are elaborated as follows." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": "Feature masking: Unlike ViT [14] backbone which directly takes image patches as the input, the Deformable DETR encoder takes the multi-scale feature maps " + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\{z_{i}\\in" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathbb{R}^{C_i\\times H_i\\times W_i}\\}_{i = 1}^K" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": " which are projected from the output of the backbone, where " + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": " denotes the number of scales. We randomly generate masking " + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\{m_i\\in \\{0,1\\}^{H_i\\times W_i}\\}_{i = 1}^K" + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": " for every scale of the feature maps with the same masking ratio. The deformable attention relies on the spatial structure of the" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19042" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": "feature maps to generate reference points and sampling locations that is used to choose points on the value matrix to perform sparse attention, so the spatial structure of the input cannot be serialized. As a result, we set the masked portion of the corresponding value matrix to zero in deformable attention to perform zero-masking, unlike [19] that only sends unmasked patches as a serialized input to ViT." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 156, + 288, + 323 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 156, + 288, + 323 + ], + "spans": [ + { + "bbox": [ + 46, + 156, + 288, + 323 + ], + "type": "text", + "content": "Reconstruction: The encoder takes the masked feature maps, and further encodes the feature maps with deformable attention. On the output features of the encoder, we fill the masked portion with a shared mask query " + }, + { + "bbox": [ + 46, + 156, + 288, + 323 + ], + "type": "inline_equation", + "content": "q_{m}" + }, + { + "bbox": [ + 46, + 156, + 288, + 323 + ], + "type": "text", + "content": " and send them to an auxiliary MAE decoder " + }, + { + "bbox": [ + 46, + 156, + 288, + 323 + ], + "type": "inline_equation", + "content": "S_{m}" + }, + { + "bbox": [ + 46, + 156, + 288, + 323 + ], + "type": "text", + "content": " to reconstruct the feature map. Following [19], we adopt an asymmetric lightweight decoder. Since the last layer of the backbone outputs, i.e., " + }, + { + "bbox": [ + 46, + 156, + 288, + 323 + ], + "type": "inline_equation", + "content": "z_{K}" + }, + { + "bbox": [ + 46, + 156, + 288, + 323 + ], + "type": "text", + "content": " contains all the semantic information, we only reconstruct it to speed up convergence and reduce computation. The last layer of MAE decoder is a linear projection whose output channels equals to the channels of " + }, + { + "bbox": [ + 46, + 156, + 288, + 323 + ], + "type": "inline_equation", + "content": "z_{K}" + }, + { + "bbox": [ + 46, + 156, + 288, + 323 + ], + "type": "text", + "content": ". Eventually, we compute mean square error (MSE) between the reconstructed and original features, but only on the masked portion, formulated as:" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 97, + 328, + 287, + 341 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 97, + 328, + 287, + 341 + ], + "spans": [ + { + "bbox": [ + 97, + 328, + 287, + 341 + ], + "type": "interline_equation", + "content": "\\hat {z} _ {K} = S _ {m} \\left(S _ {e} \\left(\\operatorname {m a s k} \\left(m, x _ {t}\\right)\\right), q _ {m}\\right) \\tag {6}", + "image_path": "f0e43a55a2508d6293fc8611644ae41974acc340a4571521ac6bf2e41ac1762e.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 55, + 344, + 287, + 357 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 344, + 287, + 357 + ], + "spans": [ + { + "bbox": [ + 55, + 344, + 287, + 357 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {m a s k}} = \\mathcal {L} _ {\\text {M S E}} \\left(\\operatorname {m a s k} \\left(m _ {K}, z _ {K} ^ {\\prime}\\right), \\operatorname {m a s k} \\left(m _ {K}, z _ {K}\\right)\\right) \\tag {7}", + "image_path": "ef8b33450373a5945f01ef94577a2ed9cbffec5b23ad51462907b7cadbb27874.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 361, + 287, + 384 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 361, + 287, + 384 + ], + "spans": [ + { + "bbox": [ + 47, + 361, + 287, + 384 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 361, + 287, + 384 + ], + "type": "inline_equation", + "content": "S_{e}, S_{m}, q_{m}" + }, + { + "bbox": [ + 47, + 361, + 287, + 384 + ], + "type": "text", + "content": " denotes the encoder of student model, the auxiliary MAE decoder and the mask query respectively." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 385, + 287, + 576 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 385, + 287, + 576 + ], + "spans": [ + { + "bbox": [ + 46, + 385, + 287, + 576 + ], + "type": "text", + "content": "Training data: Note that although student model takes both source and target images, we employ MAE only on target images, since DAOD aims to train the detector to perform better on the unlabeled target domain, and applying MAE with source images leads the model to generate source domain features with sub-optimal performance. Employing MAE on target images helps the student encoder to gain more intimate knowledge of the target domain, and boosts performance when high-quality pseudo labels are limited. We apply MAE on student model instead of teacher, for it is the student model who suffers from sub-optimal supervision of the limited pseudo boxes. Besides, the teacher model is not supervised by any detection loss. Employing MAE on the teacher model creates an encoder that is incompatible with the decoder and detection head, thus is unable to provide meaningful pseudo labels." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 576, + 287, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 576, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 576, + 287, + 696 + ], + "type": "text", + "content": "Training strategy: We train the MAE branch and detection loss simultaneously instead of following the pretrainfinetune paradigm, since pretraining leads the model to over-fit to reconstruction task due to the relatively small dataset with distinctive domain characteristics. Before the teaching process, we first train the model with " + }, + { + "bbox": [ + 46, + 576, + 287, + 696 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{sup}" + }, + { + "bbox": [ + 46, + 576, + 287, + 696 + ], + "type": "text", + "content": " in Equation(1) together with " + }, + { + "bbox": [ + 46, + 576, + 287, + 696 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{mask}" + }, + { + "bbox": [ + 46, + 576, + 287, + 696 + ], + "type": "text", + "content": " in Equation(7) to produce an enhanced initialization " + }, + { + "bbox": [ + 46, + 576, + 287, + 696 + ], + "type": "inline_equation", + "content": "\\theta_{mask}" + }, + { + "bbox": [ + 46, + 576, + 287, + 696 + ], + "type": "text", + "content": " for teaching, and as a refined re-initialization for selective retraining. The overall objective of student model in teaching process is:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 110, + 701, + 287, + 713 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 701, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 110, + 701, + 287, + 713 + ], + "type": "interline_equation", + "content": "\\mathcal {L} = \\mathcal {L} _ {\\text {t e a c h}} + \\lambda_ {\\text {m a s k}} \\mathcal {L} _ {\\text {m a s k}} \\tag {8}", + "image_path": "da29f7641c000ba407698795e63efc962137463222223f4acdb3867c4d2283ec.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\text {teach }}" + }, + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "type": "text", + "content": " has been formulated in Equation(5), and " + }, + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "\\lambda_{mask}" + }, + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "type": "text", + "content": " is the coefficient of " + }, + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{mask}" + }, + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "type": "text", + "content": " in Equation(7). As the teaching process continues, adequate amount of pseudo boxes will be produced, and the influence of " + }, + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{mask}" + }, + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "type": "text", + "content": " should be lowered to avoid the encoder over-fitting to reconstruction task. As a result, We decay " + }, + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "type": "inline_equation", + "content": "\\lambda_{mask}" + }, + { + "bbox": [ + 305, + 72, + 545, + 156 + ], + "type": "text", + "content": " as teaching continues. More details will be discussed in Section 5.4." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 164, + 479, + 177 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 164, + 479, + 177 + ], + "spans": [ + { + "bbox": [ + 306, + 164, + 479, + 177 + ], + "type": "text", + "content": "4.3. Selective Retraining Mechanism" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 183, + 545, + 338 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 183, + 545, + 338 + ], + "spans": [ + { + "bbox": [ + 304, + 183, + 545, + 338 + ], + "type": "text", + "content": "The transformer-based models tend to over-fit without large-scale training data, especially when noisy annotations are included. Here in our case, pseudo labels always contain noise since they are provided by the updating teacher model instead of ground truths. As is shown in Figure 1(b), in later stage of the teaching process, performance of certain categories are severely influenced due to the over-fitting to the incorrect pseudo labels. Worse still, since the teacher model is continually updated via EMA from student model, it could also by affected and produces even worse pseudo labels. We adopt selective retraining mechanism on student branch to help student model jump out of local optimums biased to incorrect pseudo labels." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 339, + 545, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 339, + 545, + 601 + ], + "spans": [ + { + "bbox": [ + 304, + 339, + 545, + 601 + ], + "type": "text", + "content": "To be specific, during teaching period, we continually update the teacher model via EMA without retraining it, but periodically re-initialize parts of the student model with the MAE refined parameters " + }, + { + "bbox": [ + 304, + 339, + 545, + 601 + ], + "type": "inline_equation", + "content": "\\theta_{mask}" + }, + { + "bbox": [ + 304, + 339, + 545, + 601 + ], + "type": "text", + "content": " which has been discussed in Section 4.2. Though " + }, + { + "bbox": [ + 304, + 339, + 545, + 601 + ], + "type": "inline_equation", + "content": "\\theta_{mask}" + }, + { + "bbox": [ + 304, + 339, + 545, + 601 + ], + "type": "text", + "content": " do not contain detection knowledge, its target domain encoding ability has not been corrupted by noisy pseudo labels. After re-initialization, the retrained components are allowed to leave the local optimum and can be guided by the fixed parts which can be regarded as better trained, and by an enhanced teacher which is continually updated. We do not retrain the teacher model since re-initialization cause a sudden drop of pseudo label quality, thus deteriorate the teaching process. We re-initialize the student model with MAE refined weights " + }, + { + "bbox": [ + 304, + 339, + 545, + 601 + ], + "type": "inline_equation", + "content": "\\theta_{mask}" + }, + { + "bbox": [ + 304, + 339, + 545, + 601 + ], + "type": "text", + "content": " rather than source-only trained weights or random weights for a quicker recovery, preventing its negative influence to teacher via EMA. We choose the retrained components by experimental studies. We try to perform reinitialization on different parts of the student model and choose the setting with best performance in which the decoder is kept while the backbone and encoder are retrained. More details will be discussed in Section 5.4." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 611, + 421, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 611, + 421, + 623 + ], + "spans": [ + { + "bbox": [ + 306, + 611, + 421, + 623 + ], + "type": "text", + "content": "4.4. Dynamic Threshold" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 545, + 713 + ], + "type": "text", + "content": "Existing teacher-student frameworks on DAOD set a fixed confidence threshold to select pseudo labels from outputs of the teacher model. However, we observe in experiments that as the teaching process continues, the predicted confidence scores tend to rise, introducing too many pseudo labels which contain much more incorrect labels. Besides, fixed threshold for every category ignores the category dis" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19043" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 58, + 69, + 535, + 304 + ], + "blocks": [ + { + "bbox": [ + 58, + 69, + 535, + 304 + ], + "lines": [ + { + "bbox": [ + 58, + 69, + 535, + 304 + ], + "spans": [ + { + "bbox": [ + 58, + 69, + 535, + 304 + ], + "type": "table", + "html": "
MethodDetectorpersonridercartruckbustrainmcyclebicyclemAP
FasterRCNN[35](Source)FRCNN26.938.235.618.332.49.625.828.626.9
DA-Faster[9]FRCNN29.240.443.419.738.328.523.732.732.0
UMT[12]FRCNN33.046.748.634.156.546.830.437.341.7
TIA[50]FRCNN34.846.349.731.152.148.637.738.142.3
D-adapt[25]FRCNN40.847.157.533.546.941.433.643.043.0
SIGMA[28]FRCNN44.043.960.331.650.451.531.740.644.2
\\(AT^1\\) [29]FRCNN43.754.162.331.954.449.335.247.947.4
TDD[20]FRCNN50.753.768.235.153.045.138.949.149.2
PT[5]FRCNN40.248.863.430.751.830.635.444.542.7
FCOS[40] (Source)FCOS36.936.344.118.629.38.420.331.928.2
EPM[22]FCOS44.246.658.524.845.229.128.634.639.0
SSAL[33]FCOS45.147.459.424.550.025.726.038.739.6
Def DETR[51] (Source)Def DETR37.739.144.217.226.85.821.635.528.5
SFA[44]Def DETR46.548.662.625.146.229.428.344.041.3
MTTrans[48]Def DETR47.749.965.225.845.933.832.646.543.4
\\(O^2\\text{net}\\)[17]Def DETR48.751.563.631.147.647.838.045.946.8
AQT[24]Def DETR49.352.364.427.753.746.536.046.447.1
MRT(Ours)Def DETR52.851.768.735.958.154.541.047.151.2
", + "image_path": "2ac7f117eee3857dfe0de8b7dc7d93eb39abe1c115c9cc7951a6225ea2167156.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 312, + 545, + 323 + ], + "lines": [ + { + "bbox": [ + 47, + 312, + 545, + 323 + ], + "spans": [ + { + "bbox": [ + 47, + 312, + 545, + 323 + ], + "type": "text", + "content": "Table 1. Results of Cityscapes to Foggy Cityscapes(0.02). \"FRCNN\" denotes Faster R-CNN and \"Def DETR\" denotes Deformable DETR." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 342, + 287, + 426 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 342, + 287, + 426 + ], + "spans": [ + { + "bbox": [ + 46, + 342, + 287, + 426 + ], + "type": "text", + "content": "tribution of samples. To address this issue, we initialize the thresholds for each category by a same value, and dynamically update them based on the predicted confidence scores of the source domain instances. In this way, the thresholds for each category could be updated differently. More details and discussion of the rationality and effectiveness of this method can be found in Appendix." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 439, + 128, + 453 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 439, + 128, + 453 + ], + "spans": [ + { + "bbox": [ + 47, + 439, + 128, + 453 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 459, + 110, + 470 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 459, + 110, + 470 + ], + "spans": [ + { + "bbox": [ + 47, + 459, + 110, + 470 + ], + "type": "text", + "content": "5.1. Datasets" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 478, + 287, + 502 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 478, + 287, + 502 + ], + "spans": [ + { + "bbox": [ + 47, + 478, + 287, + 502 + ], + "type": "text", + "content": "Following existing DAOD approaches [44, 48, 17, 24], we evaluate our method on the following benchmarks." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 503, + 287, + 574 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 503, + 287, + 574 + ], + "spans": [ + { + "bbox": [ + 46, + 503, + 287, + 574 + ], + "type": "text", + "content": "Cityscapes to Foggy Cityscapes: Cityscapes[10] is collected from urban scenes containing 2,975 images for training and 500 images for validation. Foggy Cityscapes[37] is constructed by a fog synthesis algorithm from Cityscapes. We use Cityscapes as source domain and Foggy Cityscapes with highest fog density(0.02) as target domain." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 575, + 287, + 635 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 575, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 46, + 575, + 287, + 635 + ], + "type": "text", + "content": "Cityscapes to BDD100k-daytime: BDD100k[47] is a large-scale driving dataset. Its daytime subset containing 36,728 training images and 5,258 validation images is commonly used in DAOD. We used Cityscapes as source domain and BDD100k-daytime as target domain." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 635, + 287, + 684 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 635, + 287, + 684 + ], + "spans": [ + { + "bbox": [ + 46, + 635, + 287, + 684 + ], + "type": "text", + "content": "Sim10k to Cityscapes(car): Sim10k[26] is a synthetic dataset from GTA game engine containing 10,000 images. We use Sim10k as source domain and \"car\" instances in Cityscapes as target domain." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 342, + 440, + 355 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 342, + 440, + 355 + ], + "spans": [ + { + "bbox": [ + 306, + 342, + 440, + 355 + ], + "type": "text", + "content": "5.2. Implementation Details" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 361, + 545, + 540 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 361, + 545, + 540 + ], + "spans": [ + { + "bbox": [ + 304, + 361, + 545, + 540 + ], + "type": "text", + "content": "We use Deformable DETR [51] as our base detector. For loss coefficients, we set " + }, + { + "bbox": [ + 304, + 361, + 545, + 540 + ], + "type": "inline_equation", + "content": "\\lambda_{unsup} = 1.0" + }, + { + "bbox": [ + 304, + 361, + 545, + 540 + ], + "type": "text", + "content": " and initial " + }, + { + "bbox": [ + 304, + 361, + 545, + 540 + ], + "type": "inline_equation", + "content": "\\lambda_{mask} = 1.0" + }, + { + "bbox": [ + 304, + 361, + 545, + 540 + ], + "type": "text", + "content": ". For the discriminators, the coefficients of backbone, encoder and decoder is set 0.3, 1.0, 1.0 respectively. We set the weight smooth parameter " + }, + { + "bbox": [ + 304, + 361, + 545, + 540 + ], + "type": "inline_equation", + "content": "\\alpha = 0.9996" + }, + { + "bbox": [ + 304, + 361, + 545, + 540 + ], + "type": "text", + "content": " in EMA. For dynamic threshold, we initialize the thresholds for each category by 0.3. For MAE branch, we use a 2-layer asymmetric decoder and a mask ratio of 0.8. We optimize the network by Adam optimizer with initial learning rate " + }, + { + "bbox": [ + 304, + 361, + 545, + 540 + ], + "type": "inline_equation", + "content": "2 \\times 10^{-4}" + }, + { + "bbox": [ + 304, + 361, + 545, + 540 + ], + "type": "text", + "content": " and batch size 8. The data augmentation methods include random horizontal flip for weak augmentation, and randomly color jittering, grayscale and Gaussian blurring for strong augmentations. Algorithms are implemented by PyTorch. More implementation details which differ between benchmarks can be seen in Appendix." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 551, + 480, + 563 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 551, + 480, + 563 + ], + "spans": [ + { + "bbox": [ + 306, + 551, + 480, + 563 + ], + "type": "text", + "content": "5.3. Comparing with Other Methods" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 545, + 713 + ], + "type": "text", + "content": "We compare our proposed MRT with other methods on the three benchmarks mentioned above. Our proposed MRT outperforms previous methods, and achieves significant improvements compared with DETR-based methods. As shown in Table 1, for categories with fewer instances (i.e. \"truck\") in Cityscapes to Foggy Cityscapes, MRT performs much better, as the data-efficient MAE branch boost the performance. For confusing categories (i.e. \"bicycle\" and \"motorcycle\"), MRT has a significant performance gain with the help of selective retraining mechanism. As shown in Table 2, on Cityscapes to BDD100k-daytime where the class distribution of target dataset is largely different from" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 46, + 693, + 287, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 693, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 693, + 287, + 713 + ], + "type": "text", + "content": "1We run Foggy(0.02) on AT's open source code to get the results instead of its originally reported Foggy(all) for a fair comparison." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19044" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 73, + 70, + 520, + 220 + ], + "blocks": [ + { + "bbox": [ + 73, + 70, + 520, + 220 + ], + "lines": [ + { + "bbox": [ + 73, + 70, + 520, + 220 + ], + "spans": [ + { + "bbox": [ + 73, + 70, + 520, + 220 + ], + "type": "table", + "html": "
MethodDetectorpersonridercartruckbusmcyclebicyclemAP
FasterRCNN[35](Source)FRCNN28.825.444.117.916.113.922.424.1
DA-Faster[9]FRCNN28.927.444.219.118.014.222.424.9
ICR-CCR-SW[45]FRCNN32.829.345.822.720.614.925.527.4
FCOS[40] (Source)FCOS38.624.854.517.216.315.018.326.4
EPM[22]FCOS39.626.855.818.819.114.520.127.8
Def DETR[51] (Source)Def DETR38.926.755.215.719.710.816.226.2
SFA[44]Def DETR40.227.657.519.123.415.419.228.9
AQT[24]Def DETR38.233.058.417.318.416.923.529.4
O2net[17]Def DETR40.431.258.620.425.014.922.730.5
MTTrans[48]Def DETR44.130.161.525.126.917.723.032.6
MRT(Ours)Def DETR48.430.963.724.725.520.222.633.7
", + "image_path": "c73b3874daf2b1478d722192102d932764c93bc6c95e3c153edc1e9db979f869.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 51, + 257, + 284, + 467 + ], + "blocks": [ + { + "bbox": [ + 198, + 228, + 394, + 239 + ], + "lines": [ + { + "bbox": [ + 198, + 228, + 394, + 239 + ], + "spans": [ + { + "bbox": [ + 198, + 228, + 394, + 239 + ], + "type": "text", + "content": "Table 2. Results of Cityscapes to BDD100k-daytime." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 51, + 257, + 284, + 467 + ], + "lines": [ + { + "bbox": [ + 51, + 257, + 284, + 467 + ], + "spans": [ + { + "bbox": [ + 51, + 257, + 284, + 467 + ], + "type": "table", + "html": "
MethodDetectorcarAP
Faster R-CNN(Source)[35]FRCNN39.4
DA-Faster[9]FRCNN41.9
MeGA-CDA[43]FRCNN44.8
GPA[45]FRCNN47.6
ViSGA[36]FRCNN49.3
KTNet[39]FRCNN50.7
PT[5]FRCNN55.1
FCOS(Source)[40]FCOS42.5
EPM[22]FCOS47.3
SSAL[33]FCOS51.8
Deformable DETR(Source)[51]Def DETR47.4
SFA[44]Def DETR52.6
AQT[24]Def DETR53.4
O2net[17]Def DETR54.1
MTTrans [29]Def DETR57.9
MRT(Ours)Def DETR62.0
", + "image_path": "adcf37c42f433f515dac3f4f585442bc06e05b26d02622490138cdc611bafd11.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 506, + 287, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 506, + 287, + 555 + ], + "spans": [ + { + "bbox": [ + 46, + 506, + 287, + 555 + ], + "type": "text", + "content": "source, MRT still achieves leading. As shown in Table 3, on Sim10k to Cityscapes(car), MRT outperforms previous SOTAs, indicating that our proposed method stays effective under larger domain gap." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 563, + 204, + 575 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 563, + 204, + 575 + ], + "spans": [ + { + "bbox": [ + 47, + 563, + 204, + 575 + ], + "type": "text", + "content": "5.4. Ablation Study and Analysis" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 582, + 287, + 617 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 287, + 617 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 287, + 617 + ], + "type": "text", + "content": "In this section, we provide ablation study and analysis of our proposed approaches. All experiments are conducted on Cityscapes to Foggy Cityscapes." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "text", + "content": "Quantitative Ablation Study: The effect of proposed modules are presented in Table 4, from which we can observe: 1) Introducing MAE branch without teacher-student framework (line 2) shows a significant improvement compared with source-only trained model, indicating that MAE is a data-efficient domain adapter. 2) MAE branch, selective retraining and dynamic filter respectively improves the performance by a large margin (line 4-6) when independently" + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 316, + 257, + 537, + 358 + ], + "blocks": [ + { + "bbox": [ + 81, + 475, + 253, + 487 + ], + "lines": [ + { + "bbox": [ + 81, + 475, + 253, + 487 + ], + "spans": [ + { + "bbox": [ + 81, + 475, + 253, + 487 + ], + "type": "text", + "content": "Table 3. Results of Sim10k to Cityscapes(car)." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 316, + 257, + 537, + 358 + ], + "lines": [ + { + "bbox": [ + 316, + 257, + 537, + 358 + ], + "spans": [ + { + "bbox": [ + 316, + 257, + 537, + 358 + ], + "type": "table", + "html": "
SourceBaselineDTRetrainMAEmAP
✓28.5
✓✓35.8
✓✓44.9
✓✓✓45.5
✓✓✓✓48.3
✓✓✓✓48.1
✓✓✓✓✓51.2
", + "image_path": "14af5fc7bd8b550b61c98e72d13376a4f62e6e89500242730cdc145339925f2f.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 365, + 545, + 422 + ], + "lines": [ + { + "bbox": [ + 305, + 365, + 545, + 422 + ], + "spans": [ + { + "bbox": [ + 305, + 365, + 545, + 422 + ], + "type": "text", + "content": "Table 4. Ablation studies of proposed modules on Cityscapes to Foggy Cityscapes. \"Source\" denotes the source-only trained model. \"Baseline\" denotes the adaptive teacher-student baseline. \"DT\", \"Retrain\" and \"MAE\" denotes proposed dynamic threshold, selective retraining and masked autoencoder branch, respectively." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 305, + 445, + 545, + 494 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 445, + 545, + 494 + ], + "spans": [ + { + "bbox": [ + 305, + 445, + 545, + 494 + ], + "type": "text", + "content": "used, illustrating their effectiveness. 3) Retraining combining with MAE refined re-initialization (line 7) further improves the performance, indicating that our proposed design maximizes the advantages of both modules." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 495, + 546, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 495, + 546, + 628 + ], + "spans": [ + { + "bbox": [ + 304, + 495, + 546, + 628 + ], + "type": "text", + "content": "Qualitative visualization analysis: We provide qualitative visualization analysis of pseudo labels and feature distributions. Figure 3 shows the selected pseudo labels. From Figure 3(b) to 3(c), MAE guide the model to provide more pseudo labels, and from Figure 3(c) to 3(d), selective retraining filters out incorrect pseudo labels and predicts closer to ground truth. Figure 4 visualizes the features of two domains by t-SNE. MAE branch provides a much better initialization compared to source-only trained model, and our proposed MRT further bridges the domain gap. More visualization figures can be seen in Appendix." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": "Analysis of MAE branch: Table 5 shows the detailed results of MAE ablation. Table 5(a) indicates that relatively high mask ratio yields a nontrivial and meaningful self-supervisory task. Table 5(b) explores the decay strategy of MAE coefficient " + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\lambda_{mask}" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": ". \"no decay\" denotes the MAE loss continually exists with fixed " + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\lambda_{mask}" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": ". \"linear\" denotes " + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\lambda_{mask}" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": " decays linearly during teaching process. \"hard\" de" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19045" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 58, + 74, + 149, + 122 + ], + "blocks": [ + { + "bbox": [ + 58, + 74, + 149, + 122 + ], + "lines": [ + { + "bbox": [ + 58, + 74, + 149, + 122 + ], + "spans": [ + { + "bbox": [ + 58, + 74, + 149, + 122 + ], + "type": "image", + "image_path": "b01752e886155a4070d7863d647a4929ac0c7ea70d534070a14663140a36fca7.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 77, + 125, + 130, + 135 + ], + "lines": [ + { + "bbox": [ + 77, + 125, + 130, + 135 + ], + "spans": [ + { + "bbox": [ + 77, + 125, + 130, + 135 + ], + "type": "text", + "content": "(a) Source-only" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 154, + 74, + 246, + 121 + ], + "blocks": [ + { + "bbox": [ + 154, + 74, + 246, + 121 + ], + "lines": [ + { + "bbox": [ + 154, + 74, + 246, + 121 + ], + "spans": [ + { + "bbox": [ + 154, + 74, + 246, + 121 + ], + "type": "image", + "image_path": "4f73a368f397709af7b0f7ff42a4c66dc7298b67340a1ab04aa6c41722b0cf02.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 179, + 125, + 221, + 135 + ], + "lines": [ + { + "bbox": [ + 179, + 125, + 221, + 135 + ], + "spans": [ + { + "bbox": [ + 179, + 125, + 221, + 135 + ], + "type": "text", + "content": "(b) Baseline" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 250, + 74, + 343, + 121 + ], + "blocks": [ + { + "bbox": [ + 250, + 74, + 343, + 121 + ], + "lines": [ + { + "bbox": [ + 250, + 74, + 343, + 121 + ], + "spans": [ + { + "bbox": [ + 250, + 74, + 343, + 121 + ], + "type": "image", + "image_path": "e5b27c2e05be8f98f50b4787986508537ae0184c2710a1639e325b92ea28d02e.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 261, + 125, + 332, + 135 + ], + "lines": [ + { + "bbox": [ + 261, + 125, + 332, + 135 + ], + "spans": [ + { + "bbox": [ + 261, + 125, + 332, + 135 + ], + "type": "text", + "content": "(c) MRT w/o Retrain" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 347, + 74, + 439, + 121 + ], + "blocks": [ + { + "bbox": [ + 347, + 74, + 439, + 121 + ], + "lines": [ + { + "bbox": [ + 347, + 74, + 439, + 121 + ], + "spans": [ + { + "bbox": [ + 347, + 74, + 439, + 121 + ], + "type": "image", + "image_path": "ee9677c7894658429c18d35d43299888f100bf44ce74e7227941f507e3b9ecb9.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 367, + 125, + 419, + 135 + ], + "lines": [ + { + "bbox": [ + 367, + 125, + 419, + 135 + ], + "spans": [ + { + "bbox": [ + 367, + 125, + 419, + 135 + ], + "type": "text", + "content": "(d) MRT (ours)" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 444, + 74, + 536, + 121 + ], + "blocks": [ + { + "bbox": [ + 444, + 74, + 536, + 121 + ], + "lines": [ + { + "bbox": [ + 444, + 74, + 536, + 121 + ], + "spans": [ + { + "bbox": [ + 444, + 74, + 536, + 121 + ], + "type": "image", + "image_path": "57023cc84755db92dd6adc3a942445ac8401f730ac4e9c8dc0be2a3e6ed174ce.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 462, + 125, + 517, + 135 + ], + "lines": [ + { + "bbox": [ + 462, + 125, + 517, + 135 + ], + "spans": [ + { + "bbox": [ + 462, + 125, + 517, + 135 + ], + "type": "text", + "content": "(e) Ground truth" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 53, + 182, + 126, + 256 + ], + "blocks": [ + { + "bbox": [ + 53, + 182, + 126, + 256 + ], + "lines": [ + { + "bbox": [ + 53, + 182, + 126, + 256 + ], + "spans": [ + { + "bbox": [ + 53, + 182, + 126, + 256 + ], + "type": "image", + "image_path": "22fca1e0697ec39f238ed943d27fa6311fb9c0bbbcaebfa4a9b0fa4f7ff1e4bf.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 63, + 259, + 115, + 269 + ], + "lines": [ + { + "bbox": [ + 63, + 259, + 115, + 269 + ], + "spans": [ + { + "bbox": [ + 63, + 259, + 115, + 269 + ], + "type": "text", + "content": "(a) Source-only" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 281, + 287, + 316 + ], + "lines": [ + { + "bbox": [ + 46, + 281, + 287, + 316 + ], + "spans": [ + { + "bbox": [ + 46, + 281, + 287, + 316 + ], + "type": "text", + "content": "Figure 4. Qualitative ablation: feature visualization of the two domains on Cityscapes to Foggy Cityscapes by t-SNE. The blue and orange points denote source and target features respectively." + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 130, + 182, + 204, + 255 + ], + "blocks": [ + { + "bbox": [ + 130, + 182, + 204, + 255 + ], + "lines": [ + { + "bbox": [ + 130, + 182, + 204, + 255 + ], + "spans": [ + { + "bbox": [ + 130, + 182, + 204, + 255 + ], + "type": "image", + "image_path": "1db509e0492abc3c2cc537a65627d028180f11520c8943e31e57047fe32c6c9e.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 138, + 259, + 197, + 269 + ], + "lines": [ + { + "bbox": [ + 138, + 259, + 197, + 269 + ], + "spans": [ + { + "bbox": [ + 138, + 259, + 197, + 269 + ], + "type": "text", + "content": "(b) Source+MAE" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 209, + 182, + 282, + 255 + ], + "blocks": [ + { + "bbox": [ + 209, + 182, + 282, + 255 + ], + "lines": [ + { + "bbox": [ + 209, + 182, + 282, + 255 + ], + "spans": [ + { + "bbox": [ + 209, + 182, + 282, + 255 + ], + "type": "image", + "image_path": "d305f8924a52b93b4ca583c2c65c024e111bcc8ec8f887a9386c8669eb95f13a.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 220, + 259, + 271, + 269 + ], + "lines": [ + { + "bbox": [ + 220, + 259, + 271, + 269 + ], + "spans": [ + { + "bbox": [ + 220, + 259, + 271, + 269 + ], + "type": "text", + "content": "(c) MRT (ours)" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 15 + }, + { + "type": "table", + "bbox": [ + 65, + 327, + 154, + 378 + ], + "blocks": [ + { + "bbox": [ + 65, + 327, + 154, + 378 + ], + "lines": [ + { + "bbox": [ + 65, + 327, + 154, + 378 + ], + "spans": [ + { + "bbox": [ + 65, + 327, + 154, + 378 + ], + "type": "table", + "html": "
Mask ratiomAP
0.547.1
0.848.3
0.946.8
", + "image_path": "64af137aa09e43943ae7586e70d52a7b5ca820e5ef9f982965c8063289505fdf.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "table_body" + } + ], + "index": 18 + }, + { + "type": "table", + "bbox": [ + 183, + 327, + 268, + 378 + ], + "blocks": [ + { + "bbox": [ + 83, + 379, + 135, + 388 + ], + "lines": [ + { + "bbox": [ + 83, + 379, + 135, + 388 + ], + "spans": [ + { + "bbox": [ + 83, + 379, + 135, + 388 + ], + "type": "text", + "content": "(a) Mask ratio" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 183, + 327, + 268, + 378 + ], + "lines": [ + { + "bbox": [ + 183, + 327, + 268, + 378 + ], + "spans": [ + { + "bbox": [ + 183, + 327, + 268, + 378 + ], + "type": "table", + "html": "
StrategymAP
No decay47.9
Linear48.2
Hard48.3
", + "image_path": "f5877e30ecf4174d1f0332d0f4ee3246f00b07f1792e90173423842cd40c3554.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "table_body" + } + ], + "index": 20 + }, + { + "type": "table", + "bbox": [ + 53, + 397, + 165, + 449 + ], + "blocks": [ + { + "bbox": [ + 187, + 379, + 264, + 388 + ], + "lines": [ + { + "bbox": [ + 187, + 379, + 264, + 388 + ], + "spans": [ + { + "bbox": [ + 187, + 379, + 264, + 388 + ], + "type": "text", + "content": "(b) Coefficient decay" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 53, + 397, + 165, + 449 + ], + "lines": [ + { + "bbox": [ + 53, + 397, + 165, + 449 + ], + "spans": [ + { + "bbox": [ + 53, + 397, + 165, + 449 + ], + "type": "table", + "html": "
Training datamAP
Source44.5
Source & Target47.0
Target48.3
", + "image_path": "905d7367758f90e1d21bb3c3a6f7ea95a24557772a0c747a7471a47df2a8d71c.jpg" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "table_body" + } + ], + "index": 22 + }, + { + "type": "table", + "bbox": [ + 176, + 397, + 274, + 449 + ], + "blocks": [ + { + "bbox": [ + 67, + 449, + 151, + 460 + ], + "lines": [ + { + "bbox": [ + 67, + 449, + 151, + 460 + ], + "spans": [ + { + "bbox": [ + 67, + 449, + 151, + 460 + ], + "type": "text", + "content": "(c) MAE Training data" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 176, + 397, + 274, + 449 + ], + "lines": [ + { + "bbox": [ + 176, + 397, + 274, + 449 + ], + "spans": [ + { + "bbox": [ + 176, + 397, + 274, + 449 + ], + "type": "table", + "html": "
MAE usagemAP
w/o MAE44.9
Pretrain42.7
MAE branch48.3
", + "image_path": "668dca3091c5643d6062b22fc330cd1f9979b37df8d5d18378bc8e84d4e065fb.jpg" + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "table_body" + } + ], + "index": 24 + }, + { + "bbox": [ + 197, + 449, + 253, + 460 + ], + "lines": [ + { + "bbox": [ + 197, + 449, + 253, + 460 + ], + "spans": [ + { + "bbox": [ + 197, + 449, + 253, + 460 + ], + "type": "text", + "content": "(d) MAE usage" + } + ] + } + ], + "index": 25, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 468, + 287, + 512 + ], + "lines": [ + { + "bbox": [ + 46, + 468, + 287, + 512 + ], + "spans": [ + { + "bbox": [ + 46, + 468, + 287, + 512 + ], + "type": "text", + "content": "Table 5. Ablation studies of MAE branch. (a) Results of different mask ratios. (b) Results of coefficient decay strategies. (c) The training data that MAE are applied to. (d) The usage of MAE (as a branch or as an independent pretraining stage)." + } + ] + } + ], + "index": 26, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 533, + 286, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 533, + 286, + 700 + ], + "spans": [ + { + "bbox": [ + 46, + 533, + 286, + 700 + ], + "type": "text", + "content": "notes that we drop the MAE branch after a certain teaching epoch. \"No decay\" receives sub-optimal result for the MAE branch benefits less when more pseudo labels are provided, thus its influence to the overall objective should be lowered at later stage of training. Table 5(c) illustrates that MAE is sensitive to domain shift of the input data. Training with target features receives better performance on target evaluation compared with the inputs that consist source images. Table 5(d) compares the result of MAE branch with the pretrain-finetune paradigm which is commonly used in pretraining tasks, indicating that in DAOD, pretraining on relatively small dataset with distinctive domain characteristics leads the model to over-fit on reconstruction task. MRT use a customised MAE branch to overcome this issue." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 59, + 701, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 701, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 59, + 701, + 287, + 713 + ], + "type": "text", + "content": "Analysis of Selective Retraining: Utilizing selective" + } + ] + } + ], + "index": 28 + }, + { + "type": "image", + "bbox": [ + 306, + 177, + 432, + 253 + ], + "blocks": [ + { + "bbox": [ + 65, + 148, + 526, + 160 + ], + "lines": [ + { + "bbox": [ + 65, + 148, + 526, + 160 + ], + "spans": [ + { + "bbox": [ + 65, + 148, + 526, + 160 + ], + "type": "text", + "content": "Figure 3. Qualitative ablation: pseudo labels for Foggy Cityscapes. \"Baseline\" denotes the adaptive teacher-student baseline." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 306, + 177, + 432, + 253 + ], + "lines": [ + { + "bbox": [ + 306, + 177, + 432, + 253 + ], + "spans": [ + { + "bbox": [ + 306, + 177, + 432, + 253 + ], + "type": "image", + "image_path": "39019c2f8f5e6f3ae5d4db0714b424771cb8bea191ce62ac97d7ffbcbb05d4ad.jpg" + } + ] + } + ], + "index": 29, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 325, + 254, + 402, + 263 + ], + "lines": [ + { + "bbox": [ + 325, + 254, + 402, + 263 + ], + "spans": [ + { + "bbox": [ + 325, + 254, + 402, + 263 + ], + "type": "text", + "content": "(a) Retrained module" + } + ] + } + ], + "index": 30, + "angle": 0, + "type": "image_caption" + } + ], + "index": 29 + }, + { + "type": "image", + "bbox": [ + 441, + 177, + 541, + 254 + ], + "blocks": [ + { + "bbox": [ + 441, + 177, + 541, + 254 + ], + "lines": [ + { + "bbox": [ + 441, + 177, + 541, + 254 + ], + "spans": [ + { + "bbox": [ + 441, + 177, + 541, + 254 + ], + "type": "image", + "image_path": "0fd8840883226dacfd2c8648769411cf6a12f831285c1cbccc081491ce431c34.jpg" + } + ] + } + ], + "index": 31, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 439, + 254, + 541, + 263 + ], + "lines": [ + { + "bbox": [ + 439, + 254, + 541, + 263 + ], + "spans": [ + { + "bbox": [ + 439, + 254, + 541, + 263 + ], + "type": "text", + "content": "(b) Re-initialization weights" + } + ] + } + ], + "index": 32, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 304, + 271, + 545, + 316 + ], + "lines": [ + { + "bbox": [ + 304, + 271, + 545, + 316 + ], + "spans": [ + { + "bbox": [ + 304, + 271, + 545, + 316 + ], + "type": "text", + "content": "Table 6. Ablation studies of selective retraining. (a) Results of different retrained modules (tick for retrained). \"Bac.\", \"Enc.\" and \"Dec.\" denotes backbone, encoder and decoder respectively. (b) Results of different re-initialization weights." + } + ] + } + ], + "index": 33, + "angle": 0, + "type": "image_caption" + } + ], + "index": 31 + }, + { + "bbox": [ + 304, + 336, + 545, + 468 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 336, + 545, + 468 + ], + "spans": [ + { + "bbox": [ + 304, + 336, + 545, + 468 + ], + "type": "text", + "content": "retraining, we periodically re-initialize some components of the model while keeping other components as enhanced parts. In teacher-student framework, we do not re-initialize teacher as has been discussed in Section 4.3. For the student model, we choose the retrained modules through experimental results. Table 6(a) shows that keeping the decoder updated and retraining backbone and decoder gets the best performance. For the re-initialization weights, Table 6(b) shows that MAE refined weights receives the best performance. Further discussion on the selective retraining mechanism can be seen in Appendix." + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 306, + 480, + 378, + 493 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 480, + 378, + 493 + ], + "spans": [ + { + "bbox": [ + 306, + 480, + 378, + 493 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 35 + }, + { + "bbox": [ + 304, + 501, + 545, + 632 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 501, + 545, + 632 + ], + "spans": [ + { + "bbox": [ + 304, + 501, + 545, + 632 + ], + "type": "text", + "content": "In this paper, we propose a novel Masked Retraining Teacher-student framework (MRT) on domain adaptive object detection task. Our customized design of masked autoencoder branch helps the student model better capture target domain characteristics and gain knowledge from limited amount of pseudo boxes, and the selective retraining mechanism allows the model to jump out of the local optimum biased to the incorrect pseudo labels. Experiments on three benchmarks confirmed the effectiveness of our model. Extensive ablation experiments demonstrate that every design helps to improve domain adaptation ability of the model." + } + ] + } + ], + "index": 36 + }, + { + "bbox": [ + 306, + 645, + 421, + 658 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 645, + 421, + 658 + ], + "spans": [ + { + "bbox": [ + 306, + 645, + 421, + 658 + ], + "type": "text", + "content": "7. Acknowledgements" + } + ] + } + ], + "index": 37 + }, + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 712 + ], + "type": "text", + "content": "This work was supported by National Natural Science Foundation of China (61925201,62132001), Zhejiang Lab (NO.2022NB0AB05) and CCF-Tencent Open Research Fund." + } + ] + } + ], + "index": 38 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19046" + } + ] + } + ], + "index": 39 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 124 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 124 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 124 + ], + "type": "text", + "content": "[1] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. Beit: Bert pre-training of image transformers. arXiv preprint arXiv:2106.08254, 2021.3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 126, + 288, + 181 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 126, + 288, + 181 + ], + "spans": [ + { + "bbox": [ + 53, + 126, + 288, + 181 + ], + "type": "text", + "content": "[2] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, et al. Language models are few-shot learners. Advances in neural information processing systems, 33:1877-1901, 2020. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 183, + 288, + 236 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 183, + 288, + 236 + ], + "spans": [ + { + "bbox": [ + 53, + 183, + 288, + 236 + ], + "type": "text", + "content": "[3] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In European conference on computer vision, pages 213-229. Springer, 2020. 1, 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 239, + 288, + 294 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 239, + 288, + 294 + ], + "spans": [ + { + "bbox": [ + 53, + 239, + 288, + 294 + ], + "type": "text", + "content": "[4] Chaoqi Chen, Zebiao Zheng, Yue Huang, Xinghao Ding, and Yizhou Yu. I3net: Implicit instance-invariant network for adapting one-stage object detectors. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12576-12585, 2021. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 296, + 287, + 361 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 296, + 287, + 361 + ], + "spans": [ + { + "bbox": [ + 53, + 296, + 287, + 361 + ], + "type": "text", + "content": "[5] Meilin Chen, Weijie Chen, Shicai Yang, Jie Song, Xin chao Wang, Lei Zhang, Yunfeng Yan, Donglian Qi, Yueting Zhuang, Di Xie, et al. Learning domain adaptive object detection with probabilistic teacher. In International Conference on Machine Learning, pages 3040-3055. PMLR, 2022. 1, 2, 6, 7" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 364, + 287, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 364, + 287, + 407 + ], + "spans": [ + { + "bbox": [ + 53, + 364, + 287, + 407 + ], + "type": "text", + "content": "[6] Mark Chen, Alec Radford, Rewon Child, Jeffrey Wu, Heewoo Jun, David Luan, and Ilya Sutskever. Generative pretraining from pixels. In International conference on machine learning, pages 1691-1703. PMLR, 2020. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 409, + 288, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 409, + 288, + 453 + ], + "spans": [ + { + "bbox": [ + 53, + 409, + 288, + 453 + ], + "type": "text", + "content": "[7] Qingchao Chen and Yang Liu. Structure-aware feature fusion for unsupervised domain adaptation. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 10567-10574, 2020. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 454, + 287, + 509 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 454, + 287, + 509 + ], + "spans": [ + { + "bbox": [ + 53, + 454, + 287, + 509 + ], + "type": "text", + "content": "[8] Qingchao Chen, Yang Liu, Zhaowen Wang, Ian Wassell, and Kevin Chetty. Re-weighted adversarial adaptation network for unsupervised domain adaptation. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 7976-7985, 2018. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 511, + 287, + 564 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 511, + 287, + 564 + ], + "spans": [ + { + "bbox": [ + 53, + 511, + 287, + 564 + ], + "type": "text", + "content": "[9] Yuhua Chen, Wen Li, Christos Sakaridis, Dengxin Dai, and Luc Van Gool. Domain adaptive faster r-cnn for object detection in the wild. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3339-3348, 2018. 1, 2, 6, 7" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 567, + 287, + 633 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 567, + 287, + 633 + ], + "spans": [ + { + "bbox": [ + 48, + 567, + 287, + 633 + ], + "type": "text", + "content": "[10] Marius Cordts, Mohamed Omran, Sebastian Ramos, Timo Rehfeld, Markus Enzweiler, Rodrigo Benenson, Uwe Franke, Stefan Roth, and Bernt Schiele. The cityscapes dataset for semantic urban scene understanding. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3213-3223, 2016. 6" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 635, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 635, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 635, + 287, + 689 + ], + "type": "text", + "content": "[11] Zhigang Dai, Bolun Cai, Yugeng Lin, and Junying Chen. Up-detr: Unsupervised pre-training for object detection with transformers. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 1601-1610, 2021. 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "text", + "content": "[12] Jinhong Deng, Wen Li, Yuhua Chen, and Lixin Duan. Unbiased mean teacher for cross-domain object detection. In" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 27, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 105 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 105 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 105 + ], + "type": "text", + "content": "Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4091-4101, 2021. 2, 6" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 308, + 107, + 545, + 183 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 107, + 545, + 183 + ], + "spans": [ + { + "bbox": [ + 308, + 107, + 545, + 183 + ], + "type": "text", + "content": "[13] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. In Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers), pages 4171–4186, 2019. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 185, + 545, + 251 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 185, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 308, + 185, + 545, + 251 + ], + "type": "text", + "content": "[14] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2020. 3, 4" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 252, + 545, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 252, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 308, + 252, + 545, + 285 + ], + "type": "text", + "content": "[15] Yaroslav Ganin and Victor Lempitsky. Unsupervised domain adaptation by backpropagation. In International conference on machine learning, pages 1180-1189. PMLR, 2015. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 286, + 545, + 319 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 286, + 545, + 319 + ], + "spans": [ + { + "bbox": [ + 308, + 286, + 545, + 319 + ], + "type": "text", + "content": "[16] Golnaz Ghiasi, Tsung-Yi Lin, and Quoc V Le. Dropblock: A regularization method for convolutional networks. Advances in neural information processing systems, 31, 2018. 3" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 321, + 545, + 363 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 321, + 545, + 363 + ], + "spans": [ + { + "bbox": [ + 308, + 321, + 545, + 363 + ], + "type": "text", + "content": "[17] Kaixiong Gong, Shuang Li, Shugang Li, Rui Zhang, Chi Harold Liu, and Qiang Chen. Improving transferability for domain adaptive detection transformers. arXiv preprint arXiv:2204.14195, 2022. 2, 6, 7" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 365, + 545, + 419 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 365, + 545, + 419 + ], + "spans": [ + { + "bbox": [ + 308, + 365, + 545, + 419 + ], + "type": "text", + "content": "[18] Song Han, Jeff Pool, Sharan Narang, Huizi Mao, Enhao Gong, Shijian Tang, Erich Elsen, Peter Vajda, Manohar Paluri, John Tran, et al. Dsd: Dense-sparse-dense training for deep neural networks. arXiv preprint arXiv:1607.04381, 2016. 2, 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 422, + 545, + 475 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 422, + 545, + 475 + ], + "spans": [ + { + "bbox": [ + 308, + 422, + 545, + 475 + ], + "type": "text", + "content": "[19] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollar, and Ross Girshick. Masked autoencoders are scalable vision learners. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 16000-16009, 2022. 2, 3, 5" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 478, + 545, + 543 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 478, + 545, + 543 + ], + "spans": [ + { + "bbox": [ + 308, + 478, + 545, + 543 + ], + "type": "text", + "content": "[20] Mengzhe He, Yali Wang, Jiaxi Wu, Yiru Wang, Hanqing Li, Bo Li, Weihao Gan, Wei Wu, and Yu Qiao. Cross domain object detection by target-perceived dual branch distillation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9570-9580, 2022. 1, 2, 6" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 544, + 545, + 589 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 544, + 545, + 589 + ], + "spans": [ + { + "bbox": [ + 308, + 544, + 545, + 589 + ], + "type": "text", + "content": "[21] Zhenwei He and Lei Zhang. Multi-adversarial faster-rcnn for unrestricted object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6668–6677, 2019. 2" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 590, + 545, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 590, + 545, + 643 + ], + "spans": [ + { + "bbox": [ + 308, + 590, + 545, + 643 + ], + "type": "text", + "content": "[22] Cheng-Chun Hsu, Yi-Hsuan Tsai, Yen-Yu Lin, and Ming-Hsuan Yang. Every pixel matters: Center-aware feature alignment for domain adaptive object detector. In European Conference on Computer Vision, pages 733-748. Springer, 2020. 6, 7" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 646, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 646, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 646, + 545, + 689 + ], + "type": "text", + "content": "[23] Gao Huang, Yixuan Li, Geoff Pleiss, Zhuang Liu, John E Hopcroft, and Kilian Q Weinberger. Snapshot ensembles: Train 1, get m for free. arXiv preprint arXiv:1704.00109, 2017. 3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "text", + "content": "[24] Wei-Jie Huang, Yu-Lin Lu, Shih-Yao Lin, Yusheng Xie, and Yen-Yu Lin. Aqt: Adversarial query transformers for domain" + } + ] + } + ], + "index": 26 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19047" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 712 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 67, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 287, + 116 + ], + "type": "text", + "content": "adaptive object detection. In 31st International Joint Conference on Artificial Intelligence, IJCAI 2022, pages 972-979. International Joint Conferences on Artificial Intelligence, 2022. 2, 6, 7" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 118, + 287, + 160 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 118, + 287, + 160 + ], + "spans": [ + { + "bbox": [ + 48, + 118, + 287, + 160 + ], + "type": "text", + "content": "[25] Junguang Jiang, Baixu Chen, Jianmin Wang, and Mingsheng Long. Decoupled adaptation for cross-domain object detection. In International Conference on Learning Representations, 2021. 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 162, + 288, + 215 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 162, + 288, + 215 + ], + "spans": [ + { + "bbox": [ + 48, + 162, + 288, + 215 + ], + "type": "text", + "content": "[26] Matthew Johnson-Roberson, Charles Barto, Rounak Mehta, Sharath Nittur Sridhar, Karl Rosaen, and Ram Vasudevan. Driving in the matrix: Can virtual worlds replace human-generated annotations for real world tasks? arXiv preprint arXiv:1610.01983, 2016. 6" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 217, + 288, + 281 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 217, + 288, + 281 + ], + "spans": [ + { + "bbox": [ + 48, + 217, + 288, + 281 + ], + "type": "text", + "content": "[27] Taekyung Kim, Minki Jeong, Seunghyeon Kim, Seokeon Choi, and Changick Kim. Diversify and match: A domain adaptive representation learning paradigm for object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12456-12465, 2019. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 282, + 288, + 336 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 282, + 288, + 336 + ], + "spans": [ + { + "bbox": [ + 48, + 282, + 288, + 336 + ], + "type": "text", + "content": "[28] Wuyang Li, Xinyu Liu, and Yixuan Yuan. Sigma: Semantic-complete graph matching for domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5291-5300, 2022. 2, 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 338, + 288, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 338, + 288, + 403 + ], + "spans": [ + { + "bbox": [ + 48, + 338, + 288, + 403 + ], + "type": "text", + "content": "[29] Yu-Jhe Li, Xiaoliang Dai, Chih-Yao Ma, Yen-Cheng Liu, Kan Chen, Bichen Wu, Zijian He, Kris Kitani, and Peter Vajda. Cross-domain adaptive teacher for object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7581-7590, 2022. 1, 2, 6, 7" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 404, + 288, + 459 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 404, + 288, + 459 + ], + "spans": [ + { + "bbox": [ + 48, + 404, + 288, + 459 + ], + "type": "text", + "content": "[30] Tsung-Yi Lin, Piotr Dólar, Ross Girshick, Kaiming He, Bharath Hariharan, and Serge Belongie. Feature pyramid networks for object detection. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2117-2125, 2017. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 460, + 288, + 502 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 460, + 288, + 502 + ], + "spans": [ + { + "bbox": [ + 48, + 460, + 288, + 502 + ], + "type": "text", + "content": "[31] Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dólár. Focal loss for dense object detection. In Proceedings of the IEEE international conference on computer vision, pages 2980-2988, 2017. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 504, + 288, + 557 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 504, + 288, + 557 + ], + "spans": [ + { + "bbox": [ + 48, + 504, + 288, + 557 + ], + "type": "text", + "content": "[32] Wei Liu, Dragomir Anguelov, Dumitru Erhan, Christian Szegedy, Scott Reed, Cheng-Yang Fu, and Alexander C Berg. Ssd: Single shot multibox detector. In European conference on computer vision, pages 21-37. Springer, 2016. 1, 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 559, + 288, + 613 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 559, + 288, + 613 + ], + "spans": [ + { + "bbox": [ + 48, + 559, + 288, + 613 + ], + "type": "text", + "content": "[33] Muhammad Akhtar Munir, Muhammad Haris Khan, M Sarfraz, and Mohsen Ali. Ssal: Synergizing between selftraining and adversarial learning for domain adaptive object detection. Advances in Neural Information Processing Systems, 34:22770-22782, 2021. 6, 7" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 614, + 288, + 669 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 614, + 288, + 669 + ], + "spans": [ + { + "bbox": [ + 48, + 614, + 288, + 669 + ], + "type": "text", + "content": "[34] Mengxue Qu, Yu Wu, Wu Liu, Qiqi Gong, Xiaodan Liang, Olga Russakovsky, Yao Zhao, and Yunchao Wei. Siri: A simple selective retraining mechanism for transformer-based visual grounding. In European Conference on Computer Vision, pages 546-562. Springer, 2022. 2, 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 670, + 288, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 288, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 288, + 712 + ], + "type": "text", + "content": "[35] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. Advances in neural information processing systems, 28, 2015. 1, 2, 6, 7" + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 712 + ], + "type": "list", + "angle": 0, + "index": 25, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 139 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 139 + ], + "type": "text", + "content": "[36] Farzaneh Rezaeanaran, Rakshith Shetty, Rahaf Aljundi, Daniel Olmeda Reino, Shanshan Zhang, and Bernt Schiele. Seeking similarities over differences: Similarity-based domain alignment for adaptive object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 9204-9213, 2021. 2, 7" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 307, + 140, + 545, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 140, + 545, + 184 + ], + "spans": [ + { + "bbox": [ + 307, + 140, + 545, + 184 + ], + "type": "text", + "content": "[37] Christos Sakaridis, Dengxin Dai, and Luc Van Gool. Semantic foggy scene understanding with synthetic data. International Journal of Computer Vision, 126(9):973-992, 2018. 6" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 186, + 547, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 186, + 547, + 228 + ], + "spans": [ + { + "bbox": [ + 307, + 186, + 547, + 228 + ], + "type": "text", + "content": "[38] Nitish Srivastava, Geoffrey Hinton, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. Dropout: a simple way to prevent neural networks from overfitting. The journal of machine learning research, 15(1):1929-1958, 2014. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 230, + 545, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 230, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 307, + 230, + 545, + 285 + ], + "type": "text", + "content": "[39] Kun Tian, Chenghao Zhang, Ying Wang, Shiming Xiang, and Chunhong Pan. Knowledge mining and transferring for domain adaptive object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 9133–9142, 2021. 7" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 286, + 545, + 331 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 286, + 545, + 331 + ], + "spans": [ + { + "bbox": [ + 307, + 286, + 545, + 331 + ], + "type": "text", + "content": "[40] Zhi Tian, Chunhua Shen, Hao Chen, and Tong He. Fcos: Fully convolutional one-stage object detection. In Proceedings of the IEEE/CVF international conference on computer vision, pages 9627-9636, 2019. 1, 2, 6, 7" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 332, + 545, + 376 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 332, + 545, + 376 + ], + "spans": [ + { + "bbox": [ + 307, + 332, + 545, + 376 + ], + "type": "text", + "content": "[41] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. Videomae: Masked autoencoders are data-efficient learners for self-supervised video pre-training. arXiv preprint arXiv:2203.12602, 2022. 2, 3" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 377, + 545, + 431 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 377, + 545, + 431 + ], + "spans": [ + { + "bbox": [ + 307, + 377, + 545, + 431 + ], + "type": "text", + "content": "[42] Pascal Vincent, Hugo Larochelle, Yoshua Bengio, and Pierre-Antoine Manzagol. Extracting and composing robust features with denoising autoencoders. In Proceedings of the 25th international conference on Machine learning, pages 1096-1103, 2008. 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 434, + 545, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 434, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 307, + 434, + 545, + 498 + ], + "type": "text", + "content": "[43] Vibashan Vs, Vikram Gupta, Poojan Oza, Vishwanath A Sindagi, and Vishal M Patel. Mega-cda: Memory guided attention for category-aware unsupervised domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4516-4526, 2021. 7" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 500, + 545, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 500, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 307, + 500, + 545, + 555 + ], + "type": "text", + "content": "[44] Wen Wang, Yang Cao, Jing Zhang, Fengxiang He, Zheng-Jun Zha, Yonggang Wen, and Dacheng Tao. Exploring sequence feature alignment for domain adaptive detection transformers. In Proceedings of the 29th ACM International Conference on Multimedia, pages 1730-1738, 2021. 2, 6, 7" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 557, + 545, + 610 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 557, + 545, + 610 + ], + "spans": [ + { + "bbox": [ + 307, + 557, + 545, + 610 + ], + "type": "text", + "content": "[45] Chang-Dong Xu, Xing-Ran Zhao, Xin Jin, and Xiu-Shen Wei. Exploring categorical regularization for domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11724-11733, 2020. 7" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 613, + 545, + 667 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 613, + 545, + 667 + ], + "spans": [ + { + "bbox": [ + 307, + 613, + 545, + 667 + ], + "type": "text", + "content": "[46] Minghao Xu, Hang Wang, Bingbing Ni, Qi Tian, and Wenjun Zhang. Cross-domain detection via graph-induced prototype alignment. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12355-12364, 2020. 2, 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 669, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 669, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 669, + 545, + 712 + ], + "type": "text", + "content": "[47] Fisher Yu, Haofeng Chen, Xin Wang, Wenqi Xian, Yingying Chen, Fangchen Liu, Vashisht Madhavan, and Trevor Darell. Bdd100k: A diverse driving dataset for heterogeneous multitask learning. In Proceedings of the IEEE/CVF con" + } + ] + } + ], + "index": 24 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19048" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 73, + 287, + 274 + ], + "type": "list", + "angle": 0, + "index": 5, + "blocks": [ + { + "bbox": [ + 66, + 73, + 287, + 94 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 73, + 287, + 94 + ], + "spans": [ + { + "bbox": [ + 66, + 73, + 287, + 94 + ], + "type": "text", + "content": "ference on computer vision and pattern recognition, pages 2636-2645, 2020. 6" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 150 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 150 + ], + "type": "text", + "content": "[48] Jinze Yu, Jiaming Liu, Xiaobao Wei, Haoyi Zhou, Yohei Nakata, Denis Gudovskiy, Tomoyuki Okuno, Jianxin Li, Kurt Keutzer, and Shanghang Zhang. Cross-domain object detection with mean-teacher transformer. arXiv preprint arXiv:2205.01643, 2022. 1, 2, 3, 6, 7" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 152, + 287, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 152, + 287, + 184 + ], + "spans": [ + { + "bbox": [ + 48, + 152, + 287, + 184 + ], + "type": "text", + "content": "[49] Dan Zhang, Jingjing Li, Lin Xiong, Lan Lin, Mao Ye, and Shangming Yang. Cycle-consistent domain adaptive faster rcnn. IEEE Access, 7:123903-123911, 2019. 1, 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 186, + 287, + 229 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 186, + 287, + 229 + ], + "spans": [ + { + "bbox": [ + 48, + 186, + 287, + 229 + ], + "type": "text", + "content": "[50] Liang Zhao and Limin Wang. Task-specific inconsistency alignment for domain adaptive object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 14217-14226, 2022. 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 231, + 287, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 231, + 287, + 274 + ], + "spans": [ + { + "bbox": [ + 48, + 231, + 287, + 274 + ], + "type": "text", + "content": "[51] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable detr: Deformable transformers for end-to-end object detection. In International Conference on Learning Representations, 2020. 1, 2, 3, 6, 7" + } + ] + } + ], + "index": 4 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "19049" + } + ] + } + ], + "index": 6 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/e14b4021-babf-4da5-a112-3aa5b237ce50_content_list.json b/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/e14b4021-babf-4da5-a112-3aa5b237ce50_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..db597dd6654fd1e25fef9da258d818cef93e5c9b --- /dev/null +++ b/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/e14b4021-babf-4da5-a112-3aa5b237ce50_content_list.json @@ -0,0 +1,1676 @@ +[ + { + "type": "text", + "text": "Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos", + "text_level": 1, + "bbox": [ + 104, + 128, + 867, + 174 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Zhiqiang Shen $^{1,5*}$ , Xiaoxiao Sheng $^{1*}$ , Hehe Fan $^{2\\dagger}$ , Longguang Wang $^{3}$ , Yulan Guo $^{4}$ , Qiong Liu $^{5}$ , Hao Wen $^{5}$ , Xi Zhou $^{1,5}$ $^{1}$ Shanghai Jiao Tong University $^{2}$ Zhejiang University $^{3}$ Aviation University of Air Force $^{4}$ Sun Yat-sen University $^{5}$ CloudWalk", + "bbox": [ + 122, + 202, + 849, + 273 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 308, + 313, + 325 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Recently, the community has made tremendous progress in developing effective methods for point cloud video understanding that learn from massive amounts of labeled data. However, annotating point cloud videos is usually notoriously expensive. Moreover, training via one or only a few traditional tasks (e.g., classification) may be insufficient to learn subtle details of the spatio-temporal structure existing in point cloud videos. In this paper, we propose a Masked Spatio-Temporal Structure Prediction (MaST-Pre) method to capture the structure of point cloud videos without human annotations. MaST-Pre is based on spatio-temporal point-tube masking and consists of two self-supervised learning tasks. First, by reconstructing masked point tubes, our method is able to capture the appearance information of point cloud videos. Second, to learn motion, we propose a temporal cardinality difference prediction task that estimates the change in the number of points within a point tube. In this way, MaST-Pre is forced to model the spatial and temporal structure in point cloud videos. Extensive experiments on MSRAction-3D, NTU-RGBD, NvGesture, and SHREC'17 demonstrate the effectiveness of the proposed method. The code is available at https://github.com/JohnsonSign/MaST-Pre.", + "bbox": [ + 76, + 340, + 473, + 690 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 717, + 209, + 734 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In physics, motion is the phenomenon in which position changes over time. Because point clouds provide precise position information, i.e., 3D coordinates, point cloud videos, which evolve over time, can accurately describe the 3D motion in the real world. Effectively understanding point cloud videos can significantly improve intelligent agents on the interaction with environments. Therefore, the community has developed a few effective methods for", + "bbox": [ + 75, + 743, + 468, + 864 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/b40a14514a2720f9027a0ed9d71f7e3584cc5f0ec63cfe8e21642e0a7eb9394c.jpg", + "image_caption": [ + "Figure 1. Our MaST-Pre is based on spatio-temporal point-tube masking. To enable a model to capture the appearance structure in point cloud videos, we ask it to reconstruct masked point tubes. To equip the model with motion modeling ability, we develop a temporal cardinality difference prediction task." + ], + "image_footnote": [], + "bbox": [ + 504, + 308, + 888, + 526 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "point cloud video understanding, including video classification [9-12, 40, 50] and semantic segmentation [6, 24, 42, 43]. However, most of these methods are based on supervised learning and that requires much effort to carefully annotate massive amounts of labels. Moreover, learning via only classification or segmentation may make deep neural networks take too much emphasis on the task itself but largely ignore the subtle details of the instinct spatiotemporal structure in point cloud videos. To alleviate those problems, we propose a self-supervised learning method on point cloud videos.", + "bbox": [ + 496, + 627, + 893, + 792 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Self-supervised learning uses supervisory signals from the data itself and enables deep neural networks to learn from massive data without human annotations. This is important to recognize more subtle patterns in data. Networks pre-trained with self-supervised learning usually yield higher performance than when solely trained in a supervised manner [5, 15, 16, 19]. Although self-supervised", + "bbox": [ + 496, + 795, + 895, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*These authors contributed equally.", + "bbox": [ + 94, + 875, + 284, + 887 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "† Corresponding author.", + "bbox": [ + 96, + 887, + 222, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "16580", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "learning has been applied to images [15], videos [13, 37] and static point clouds [29, 47], it has not been promoted on 4D signals, such as point cloud videos. Visual signals in point cloud videos can be divided into appearance and motion. While appearance specifies which objects are in videos, motion describes their dynamics. Therefore, self-supervised learning on point cloud videos should carefully make the most of the appearance and motion structure.", + "bbox": [ + 75, + 90, + 468, + 210 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this paper, we propose a Masked Spatio-Temporal Structure Prediction (MaST-Pre) method for self-supervised learning on point cloud videos (Fig. 1). MaST-Pre is based on a masking strategy, which has been proven effective in a range of applications. For example, because of the canonical structure, images can be easily segmented into multiple patches for masking [8, 15], which in the case of video are extended to patch tubes [13, 37]. For unstructured static point clouds, spherical support domain masking can be used for masked autoencoder [29, 47]. However, the spatial irregularity and temporal regularity make point cloud videos require a more elaborate masking strategy. Our method is based on a masked point tube mechanism, where a point tube is a local area expanding over a short time [11].", + "bbox": [ + 75, + 213, + 470, + 425 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Based on point-tube masking, our MaST-Pre employs two self-supervised tasks to capture the appearance and motion structure, respectively. First, to learn the appearance structure, MaST-Pre is asked to predict the invisible parts of the input from unmasked points. Second, to capture the dynamics in point tubes, we propose the temporal cardinality difference, which can be calculated online from inputs without additional parameters. Cardinality can reflect basic structures (e.g., line, edge, and plane) of static point clouds [21]. In this paper, we extend it to a temporal version so that it can model the dynamics of point cloud videos. Intuitively, the temporal cardinality difference characterizes the flow of points within a short time. Therefore, inferring the temporal cardinality difference of masked point tubes facilitates MaST-Pre to learn motion-informative representations. Our contributions are summarized as follows:", + "bbox": [ + 75, + 426, + 470, + 667 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We design a 4D scheme of masked prediction for self-supervised learning on point cloud videos, termed as MaST-Pre. Our MaST-Pre jointly learns the appearance and motion structure of point cloud videos.", + "- We propose the temporal cardinality difference, a simple and effective motion feature directly captured from raw input points. It explicitly guides MaST-Pre to learn motion-informative representations.", + "- Extensive experiments and ablation studies on several benchmark datasets validate that our MaST-Pre learns rich representations of point cloud videos." + ], + "bbox": [ + 94, + 684, + 468, + 881 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 89, + 640, + 106 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this section, we first briefly review visual mask prediction for self-supervised learning. Then, we present recent advances in self-supervised learning on point clouds and dynamics modeling for point cloud videos.", + "bbox": [ + 496, + 114, + 890, + 176 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Visual Mask Prediction", + "text_level": 1, + "bbox": [ + 500, + 181, + 718, + 196 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Mask prediction has been proven to be an excellent self-supervised task for visual representation learning [8,15,45]. By reconstructing target signals from the masked input, mask prediction enables the network to learn rich representations and boosts self-supervised learning [2,4,39,41]. Chen et al. [4] extended GPT [3] to operate the pixel sequence for prediction. Bao et al. [2] and Wang et al. [39] introduced another successful framework, BERT [19], to predict the identities of masked tokens.", + "bbox": [ + 496, + 205, + 890, + 340 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Then, He et al. [15] proposed MAE as a scalable vision learner to predict the pixels of masked patches. Feichtenhofer et al. [13] and Tong et al. [37] extended MAE to video representation learning by masking patch tubes. Wei et al. [41] developed MaskFeat to predict the HOG features of masked spatio-temporal tubes for self-supervised video pretraining. The regular structure of images and videos makes it easy to obtain patches or patch tubes, which facilitates the design of masking strategies. Pang et al. [29] extended MAE to unstructured static point clouds and designed a masking strategy based on the local spatial neighborhoods. However, point cloud videos are not only spatially irregular but also temporally misaligned across frames [9, 11]. To remedy this, we design a point-tube masking strategy.", + "bbox": [ + 496, + 340, + 892, + 554 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. Self-supervised Learning on Point Clouds", + "text_level": 1, + "bbox": [ + 500, + 560, + 854, + 575 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Contrastive learning has made significant progress on static point clouds [17, 32, 44, 49]. Xie et al. [44] proposed PointContrast to discriminate two geometric views of matched points using contrastive loss. Hou et al. [17] introduced contextual contrastive learning to PointContrast for data-efficient point pre-training. Rao et al. [32] mapped the local and global features to shared representation space and applied a contrastive loss on them. Zhang et al. [49] used the instance discrimination task on two augmented versions of a point cloud, while Huang et al. [18] pre-trained static point clouds using spatio-temporal augmentations. They transformed different views at point, region, object, and scene levels, and then used contrastive learning to judge their semantic consistency. However, there are limited augmentation methods that can guarantee the semantic consistency of point clouds, let alone point cloud videos.", + "bbox": [ + 496, + 584, + 890, + 825 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Prediction-based methods on point clouds also attract a lot of attention. Yang et al. [46] proposed a folding-based autoencoder that deforms a 2D grid to reconstruct the target 3D point cloud. Recently, mask prediction has been extended to static point clouds. Liu et al. [22] designed a point", + "bbox": [ + 496, + 825, + 890, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "16581", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/dad6bc8cee570461f85a6ff64696d5f6822c600719193bde0ee7de9205b7b572.jpg", + "image_caption": [ + "Figure 2. Illustration of the proposed MaST-Pre method. First, given a point cloud video, MaST-Pre divides it into several point tubes and masks part of them. Then, based on an encoder-decoder architecture, MaST-Pre attempts to recover masked point tubes and predict their temporal cardinality difference." + ], + "image_footnote": [], + "bbox": [ + 94, + 88, + 872, + 300 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "discrimination task for masked patches. Yu et al. [47] proposed PointBERT with an offline point tokenizer. Pang et al. [29] used a simpler task, reconstructing masked point coordinates, for point pre-training in an end-to-end manner. However, these methods solely focus on the geometric representation learning of static point clouds. In this paper, on top of learning appearance information, an explicit motion information learning method is designed for point cloud videos.", + "bbox": [ + 75, + 373, + 472, + 508 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.3. Dynamics Modeling for Point Cloud Videos", + "text_level": 1, + "bbox": [ + 76, + 525, + 444, + 542 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Supervised learning dominates point cloud video research. [11, 12] and [9, 10, 42, 43] use convolution-based methods and attention-based methods to implicitly learn the long-term features of point cloud videos, respectively. In addition, [24, 40, 50] apply empirical-based dynamics methods modeling point cloud videos. Wang et al. [40] introduced temporal rank pooling [14] to capture the frame-level dynamics. Zhong et al. [50] proposed a two-stream framework and used feature-level ST-surfaces [30] in the dynamics learning branch. Liu et al. [24] used a scene flow estimator [23] or an alternative grouping method to do point tracking for dynamics modeling. Although these methods are effective, they require complex calculations or additional modules.", + "bbox": [ + 75, + 551, + 468, + 762 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Self-supervised learning on point cloud videos is understudied [34, 35]. Wang et al. [38] pre-trained the encoder by predicting the temporal order of shuffled segments to learn the dynamics of point cloud videos. Zhang et al. [48] developed complete-to-partial 4D distillation to predict the representations of point cloud frames within a short time window. However, these methods learn motion information using clip-level or frame-level pretext tasks. In this paper, we propose the temporal cardinality difference prediction", + "bbox": [ + 75, + 763, + 470, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "for fine-grained dynamics learning on point cloud videos.", + "bbox": [ + 500, + 375, + 877, + 388 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Method", + "text_level": 1, + "bbox": [ + 500, + 402, + 589, + 417 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The architecture of our MaST-Pre is illustrated in Fig. 2. Given a point cloud video, it is first divided into multiple point tubes. Next, a masking operation is performed, separating these point tubes into visible and invisible parts. The visible ones are fed to an encoder, and then their updated embeddings are fed to the decoder along with the masked point tubes. Afterward, two-stream prediction tasks are implemented to recover the point coordinates within masked point tubes and to infer their temporal cardinality differences, respectively. Intuitively, enabling the decoder to perform well on two-stream prediction tasks demands the encoder to learn representations rich in appearance and motion information jointly.", + "bbox": [ + 496, + 428, + 890, + 625 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Masking Strategy", + "text_level": 1, + "bbox": [ + 500, + 635, + 671, + 651 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The masking strategy includes three steps: input division, embedding, and masking operation.", + "bbox": [ + 498, + 657, + 888, + 688 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Division. Point tubes are introduced as division units of the input point cloud video. Specifically, given a point cloud video $\\pmb{P}$ , Farthest Point Sampling is used to select $N$ key points $\\hat{\\pmb{p}}$ from the input. Next, we construct one point tube for each key point. The point tube centered at $i$ -th key point $\\hat{p}_i$ is denoted as $\\pmb{T}\\pmb{u}\\pmb{e}_{\\hat{p}_i} = \\{p \\mid p \\in \\pmb{P}, \\mathcal{D}_s(p, \\hat{p}_i) < r, \\mathcal{D}_t(p, \\hat{p}_i) < \\frac{l}{2}\\}$ , where $p$ is one of the input points, $\\mathcal{D}_s$ is the Euclidean distance, $\\mathcal{D}_t$ is the difference in frame timestamps of two points, $r$ is the radius of a spatial neighborhood and $l$ is the number of frames in a point tube. Then, we use random sampling to select $n$ points in each spatial neighborhood.", + "bbox": [ + 496, + 689, + 890, + 869 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this way, a point cloud video is divided into $N$ point tubes, and each point tube contains $l \\times n$ points. To en", + "bbox": [ + 500, + 869, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "16582", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/8defb88c45c42b96b704055e14bff5a18eb9ff14f4944abf73fc46700d127cc9.jpg", + "image_caption": [ + "(a) Cardinality Histogram", + "Figure 3. Illustration of Cardinality Histogram (a) and Temporal Cardinality Difference (b)." + ], + "image_footnote": [ + "I $\\sim$ VIII Octant", + "-·-·", + "Oct", + "ant Central Line", + "#", + "Points" + ], + "bbox": [ + 80, + 88, + 509, + 308 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/20ca32a24269e34bf21bac915d8dea42c334d81c44700f53ad35efbede127f12.jpg", + "image_caption": [ + "(b) Temporal Cardinality Difference" + ], + "image_footnote": [ + "$d_{1}d_{2}d_{3}d_{4}$", + "Angular Distance to Octant Central Line" + ], + "bbox": [ + 532, + 89, + 888, + 308 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "sure all points are covered by point tubes, $r$ and $l$ are set to maintain a minor overlap between adjacent point tubes.", + "bbox": [ + 75, + 411, + 468, + 441 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "**Embedding.** Following our baseline [9], each point tube is encoded into an embedding:", + "bbox": [ + 75, + 441, + 468, + 470 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {E} _ {\\hat {p} _ {i}} = \\sum_ {t = 1} ^ {l} \\sum_ {p \\in \\boldsymbol {T u b e} _ {\\hat {p} _ {i}} ^ {t}} f (p - \\hat {p} _ {i}), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 163, + 479, + 468, + 527 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbf{Tube}_{\\hat{p}_i}^t$ is the $t$ -th frame of the point tube centered at $\\hat{p}_i$ and $f(\\cdot)$ is an MLP-based feature extractor. More details can be found in [9].", + "bbox": [ + 75, + 536, + 468, + 580 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Masking. The design of the masking operation is related to the information redundancy of input [13, 15, 37]. Because of spatio-temporal coherence, the redundancy of the point cloud video is higher than low-dimensional data. Therefore, our MaST-Pre uses a high masking ratio on point cloud videos and the empirical result is $75\\%$ . A high ratio is helpful to alleviate information leakage and make reconstruction a meaningful self-supervised task. In addition, our MaST-Pre uses random masking of point tubes. As a spacetime-agnostic method, random masking is more effective than structure-aware strategies [13].", + "bbox": [ + 75, + 582, + 468, + 750 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Autoencoding", + "text_level": 1, + "bbox": [ + 76, + 756, + 220, + 772 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Our autoencoder is based on vanilla Transformers of point cloud videos [9]. An asymmetric encoder-decoder design is introduced to MaST-Pre.", + "bbox": [ + 75, + 779, + 468, + 824 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Encoder. To better capture the dynamics of point cloud videos, joint spatio-temporal attention is adopted [1,25]. In addition, only the visible point tubes with spatio-temporal positional embeddings are fed into the encoder during pretraining.", + "bbox": [ + 75, + 824, + 468, + 900 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Decoder. The decoder is similar to our encoder but a lightweight vanilla Transformer [9]. It takes both encoded point tubes and masked ones as input. By adding a full set of spatio-temporal positional embeddings to all tokens, location clues are provided for self-supervised learning. After decoding, only the embeddings of masked point tubes are fed to the following prediction heads.", + "bbox": [ + 496, + 411, + 893, + 517 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Two-stream Prediction", + "text_level": 1, + "bbox": [ + 500, + 526, + 712, + 541 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "It is demonstrated in [31, 36] that effective video representation integrates appearance and motion information. Therefore, two-stream self-supervised tasks are proposed to explicitly predict motions and reconstruct the appearance of masked point cloud videos.", + "bbox": [ + 496, + 549, + 893, + 625 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Appearance Stream. The reconstruction objectives are the point coordinates of masked point tubes. The $l_{2}$ Chamber Distance loss is used between predictions $P_{pre} \\in \\mathbb{R}^{l \\times n \\times 3}$ and the ground truth $P_{gt} \\in \\mathbb{R}^{l \\times n \\times 3}$ :", + "bbox": [ + 496, + 625, + 893, + 686 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {L} _ {a p p} = \\frac {1}{l} \\sum_ {i = 1} ^ {l} \\left\\{\\frac {1}{| \\boldsymbol {P} _ {p r e} ^ {i} |} \\sum_ {a \\in \\boldsymbol {P} _ {p r e} ^ {i}} \\min _ {b \\in \\boldsymbol {P} _ {g t} ^ {i}} \\| a - b \\| _ {2} ^ {2} + \\right. \\tag {2} \\\\ \\left. \\frac {1}{| \\boldsymbol {P} _ {g t} ^ {i} |} \\sum_ {b \\in \\boldsymbol {P} _ {g t} ^ {i}} \\min _ {a \\in \\boldsymbol {P} _ {p r e} ^ {i}} \\| b - a \\| _ {2} ^ {2} \\right\\}. \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 522, + 696, + 890, + 799 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Motion Stream. We propose the temporal cardinality difference as the target of the motion prediction stream. As shown in Fig. 3(a), the spherical support domain of the key point is divided into 8 octants. We follow the conventional rule that the area where the $xyz$ -coordinates are greater than 0 is the first octant I and then increases counterclockwise.", + "bbox": [ + 496, + 809, + 893, + 898 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "16583", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Then, count the cardinality of each octant into the corresponding bin of a histogram. To alleviate the noise in real-world point clouds, a probabilistic approach is employed. Specifically, calculate the angular distance $d$ of each point to the central line of its current octant, and divide it by $90^{\\circ}$ to normalize. For example, the current octant of Point2 (the green one in Fig. 3(a)) is octant III. The angular difference $d2$ between Point2 and the central dashed line of octant III is $30^{\\circ}$ . Consequently, the probabilities of Point2 belonging to octant IV and III are $\\frac{1}{3}$ (i.e., $\\frac{30^{\\circ}}{90^{\\circ}}$ ) and $\\frac{2}{3}$ (i.e., $\\frac{60^{\\circ}}{90^{\\circ}}$ ), respectively. In particular, when a point falls on an axis (e.g., the $-y$ axis), its probabilities belonging to octant IV and III are both 0.5.", + "bbox": [ + 75, + 90, + 472, + 286 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Next, as shown in Fig. 3(b), the cardinality histograms $C \\in \\mathbb{R}^8$ between adjacent frames of a point tube are subtracted to obtain its temporal cardinality difference $CD \\in \\mathbb{R}^8$ , which constitutes the ground truth $M_{gt} \\in \\mathbb{R}^{(l-1) \\times 8}$ of the motion stream. The decoded embeddings of masked point tubes are passed through a linear layer to obtain the motion prediction $M_{pre} \\in \\mathbb{R}^{(l-1) \\times 8}$ . The smooth $l_1$ loss of $i$ -th $CD$ between prediction and ground truth is denoted as $\\mathcal{L}_m^i$ . The loss of our motion stream is denoted as $\\mathcal{L}_{motion}$ :", + "bbox": [ + 76, + 287, + 472, + 425 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {m} ^ {i} = \\left\\{ \\begin{array}{l l} 0. 5 \\times \\left(M _ {p r e} ^ {i} - M _ {g t} ^ {i}\\right) ^ {2}, & \\text {i f} \\left| M _ {p r e} ^ {i} - M _ {g t} ^ {i} \\right| < 1 \\\\ \\left| M _ {p r e} ^ {i} - M _ {g t} ^ {i} \\right| - 0. 5, & \\text {o t h e r w i s e} \\end{array} , \\right. \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 84, + 436, + 468, + 476 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {m o t i o n}} = \\frac {1}{l - 1} \\sum_ {i = 1} ^ {l - 1} \\mathcal {L} _ {m} ^ {i}. \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 187, + 491, + 468, + 532 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Overall, the total loss of our MaST-Pre is defined as:", + "bbox": [ + 96, + 540, + 444, + 554 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\text {a p p}} + \\mathcal {L} _ {\\text {m o t i o n}}. \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 183, + 568, + 468, + 585 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "With both loss terms, our MaST-Pre can simultaneously learn the geometry and dynamics of point cloud videos.", + "bbox": [ + 76, + 597, + 468, + 628 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 643, + 209, + 659 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Our experiments are conducted on four point cloud video datasets. Following [13, 15, 37], we implement end-to-end fine-tuning, semi-supervised learning, and transfer learning to evaluate the pre-trained MaST-Pre. Afterward, ablation studies are conducted to analyze the design of our MaST-Pre and show the visualization results.", + "bbox": [ + 75, + 667, + 468, + 758 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Datasets", + "text_level": 1, + "bbox": [ + 76, + 770, + 179, + 785 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In this paper, to demonstrate the effectiveness of our spatio-temporal representations, we focus on long-term point cloud video tasks, including 4D action recognition and 4D gesture recognition.", + "bbox": [ + 75, + 794, + 468, + 854 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "MSRAction-3D [20] and NTU-RGBD [33] are utilized for the action recognition task. (1) MSRAction-3D is comprised of 567 videos in 20 daily actions. The average", + "bbox": [ + 75, + 854, + 468, + 901 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/b0267a0a46ddf3737421ad2f50f3625cc63730be11db54ecedfc37f6575adde9.jpg", + "table_caption": [ + "Table 1. Action recognition accuracy on MSRAction-3D." + ], + "table_footnote": [], + "table_body": "
MethodsAccuracy (%)
Supervised LearningMeteorNet [24]88.50
PSTNet [11]91.20
PSTNet++ [12]92.68
Kinet [50]93.27
PPTr [43]92.33
P4Transformer [9]90.94
PST-Transformer [10]93.73
End-to-end Fine-tuningP4Transformer + MaST-Pre91.29
PST-Transformer + MaST-Pre94.08
", + "bbox": [ + 501, + 101, + 890, + 262 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "frame number contained in each video is about 40. Following [9, 10], 270 videos are used as the training set and 297 videos are adopted as the test data. (2) NTU-RGBD consists of 56,880 videos with 60 fine-grained action categories. The frame number of each video is about 30 to 300. Under the cross-subject setting [33], 40,320 training videos and 16,560 test videos are used.", + "bbox": [ + 496, + 300, + 890, + 405 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "SHREC'17 [7] and NvGesture [28] are utilized for the gesture recognition task. (1) SHREC'17 is comprised of 2800 videos in 28 gestures. Following [7], this dataset is split into 1960 training videos and 840 test videos. (2) NvGesture consists of 1532 videos with 25 gesture classes. Following [27], 1050 videos are assigned to the training set and the remaining 482 videos to the test set.", + "bbox": [ + 496, + 412, + 892, + 518 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Pre-training", + "text_level": 1, + "bbox": [ + 500, + 547, + 633, + 564 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "During pre-training, given a point cloud video, 24 frames are densely sampled and 1024 points are selected for each frame. Following [9, 10], the frame sampling stride is set to 2/1 on NTU-RGBD/MSRAction-3D and only random scaling is employed for data augmentation. For division and embedding, the temporal downsampling rate is set to 2 and the temporal kernel size $l$ of each point tube is set to 3. Meanwhile, the spatial downsampling rate is set to 32. The radius of each support domain $r$ is set to 0.1/0.3 on NTU-RGBD/MSRAction-3D and the number of neighbor points $n$ within the spherical query is set to 32. The masking ratio is set to $75\\%$ unless otherwise specified.", + "bbox": [ + 496, + 577, + 890, + 758 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "P4Transformer [9] is utilized as our encoder, which consists of 10/5 layers of vanilla Transformers on NTU-RGBD/MSRAction-3D. The decoder is a 4-layer transformer. To verify the extensibility, PST-Transformer [10] is also used as an encoder on MSRAction-3D. Our MaST-Pre is pre-trained for 200 epochs and linear warmup is utilized for the first 10 epochs. The AdamW optimizer is used with a batch size of 128, and the initial learning rate is set to 0.001 with a cosine decay strategy.", + "bbox": [ + 496, + 763, + 892, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "16584", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/9e958dc1832dc616d4eb9b29c34459f92d08dc04d27949ed942bfb50bee6a814.jpg", + "table_caption": [ + "Table 2. Action recognition accuracy (%) on NTU-RGBD under cross-subject setting." + ], + "table_footnote": [], + "table_body": "
MethodsAcc.
3DV-Motion [40]84.5
3DV-PointNet++ [40]88.8
PSTNet [11]90.5
PSTNet++ [12]91.4
Kinet [50]92.3
P4Transformer [9]90.2
PST-Transformer [10]91.0
P4Transformer + MaST-Pre (End-to-end Fine-tuning)90.8
P4Transformer + MaST-Pre (50% Semi-supervised)87.8
", + "bbox": [ + 76, + 114, + 468, + 275 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. End-to-end Fine-tuning", + "text_level": 1, + "bbox": [ + 76, + 301, + 294, + 316 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We first evaluate our MaST-Pre by fine-tuning the pretrained encoder with a new classifier in a supervised manner. End-to-end fine-tuning experiments are conducted on NTU-RGBD and MSRAction-3D, respectively. In each experiment, the same dataset is used for pre-training and fine-tuning.", + "bbox": [ + 75, + 323, + 468, + 412 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "MSRAction-3D. During fine-tuning, 24 frames are densely sampled and 2048 points are selected in each frame. Following [11], the spatial search radius is set to 0.7. The model is trained for 50 epochs with a batch size of 12 on 4 GPUs. We use the AdamW optimizer and the initial learning rate is set to 0.001 with a cosine decay strategy. As shown in Table 1, compared with baselines trained in a fully supervised manner, our MaST-Pre introduces accuracy improvements for both P4Transformer and PST-Transformer. According to prior experience, the masked autoencoder needs to be fed a considerable amount of data in the pretraining stage to learn useful knowledge [13, 15]. However, the MSRAction-3D dataset is too small to bring significant improvement.", + "bbox": [ + 75, + 414, + 468, + 625 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "NTU-RGBD. The setup of fine-tuning is the same as pre-training, except that the pre-trained model is fine-tuned for 20 epochs with a batch size of 48 on 8 GPUs and the initial learning rate is set to 0.0005. From the end-to-end fine-tuning in Table 2, we can see that our pre-training method introduces an accuracy improvement compared with the baseline. By predicting the spatio-temporal structure, our MaST-Pre learns appearance and motion information during pre-training.", + "bbox": [ + 75, + 626, + 468, + 762 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.4. Semi-supervised Learning", + "text_level": 1, + "bbox": [ + 76, + 771, + 313, + 787 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We also evaluate the learned representations using a semi-supervised learning experiment. Specifically, the cross-subject training set of NTU-RGBD is used for pretraining, and then only a $50\\%$ training set is used for finetuning in a supervised manner. The setup of our semi-supervised learning experiment is the same as end-to-end fine-tuning on NTU-RGBD (Sec. 4.3).", + "bbox": [ + 75, + 794, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/4119c9b3a749d6521f5e57b7cd5750c0c6a8147f9497e3765f19aae924de9410.jpg", + "table_caption": [ + "Table 3. Gesture recognition accuracy (\\%) on NvGesture (NvG) and SHREC'17 (SHR)." + ], + "table_footnote": [], + "table_body": "
MethodsNvGSHR
FlickerNet [26]86.3-
PLSTM [27]85.987.6
PLSTM-PSS [27]87.393.1
Kinet [50]89.195.2
P4Transformer [9] (30 Epochs)84.887.5
P4Transformer [9] (50 Epochs)87.791.2
P4Transformer + MaST-Pre (30 Epochs)87.690.2
P4Transformer + MaST-Pre (50 Epochs)89.392.4
", + "bbox": [ + 501, + 114, + 890, + 262 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "From Table 2, we can see that the $50\\%$ semi-supervised result produced by our MaST-Pre achieves comparable performance to the fully supervised baseline even with only limited annotated data. This clearly demonstrates that MaST-Pre learns high-quality representations.", + "bbox": [ + 498, + 287, + 890, + 364 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.5. Transfer Learning", + "text_level": 1, + "bbox": [ + 500, + 373, + 678, + 388 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To evaluate the generalization ability of the representations learned by MaST-Pre, we conduct experiments by transferring the pre-trained encoder to other datasets. Specifically, the encoder is first pre-trained on NTU-RGBD following the setup in Sec. 4.2, and then fine-tuned with a new classifier on NvGesture and SHREC'17, respectively. Our transfer experiments are not only cross-dataset but also cross-task, i.e., from action recognition to gesture recognition. We compare our fine-tuned results to the fully supervised baseline in Table 3.", + "bbox": [ + 496, + 397, + 890, + 547 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "During fine-tuning, an AdamW optimizer with a batch size of 24 is used, and the initial learning rate is set to 0.002 with a cosine decay strategy. The pre-trained model is fine-tuned for 50 epochs on NvGesture and SHREC'17. As shown in Table 3, our MaST-Pre pre-training facilitates the P4Transformer to produce superior accuracy compared to the fully supervised baseline. Moreover, our MaST-Pre also performs faster convergence. Compared with the baseline without pre-training, significant improvements are achieved after fine-tuning for only 30 epochs (e.g., $84.8\\% \\rightarrow 87.6\\%$ on NvGesture and $87.5\\% \\rightarrow 90.2\\%$ on SHREC'17). This demonstrates that our MaST-Pre has excellent generalization ability across different tasks, facilitating the accuracy improvement of downstream tasks.", + "bbox": [ + 496, + 549, + 890, + 760 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.6. Ablation Studies", + "text_level": 1, + "bbox": [ + 500, + 770, + 663, + 785 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In order to balance authority and efficiency, the experiments of ablation studies are conducted on $10\\%$ NTU-RGBD, which contains 4032 training videos and 1656 test videos with category balance.", + "bbox": [ + 498, + 794, + 890, + 854 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Architecture Design. Our MaST-Pre utilizes a two-stream prediction to jointly learn both appearance and motion information. To demonstrate the effectiveness of this", + "bbox": [ + 498, + 854, + 890, + 898 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "16585", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/9528bb91f590fd312dfdf100d83b75bff3863b40d801f734f3c09766605af0c0.jpg", + "image_caption": [ + "Figure 4. Visualization of reconstruction results. For each action sample, the ground truth lies in the first row, the masked video lies in the second row, and the result lies in the third row." + ], + "image_footnote": [], + "bbox": [ + 91, + 85, + 470, + 441 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1148d5257b196bd26e29b7ac0286ca37566e3d11fd510131040ecc8b0dc302c2.jpg", + "image_caption": [], + "image_footnote": [ + "Rnne aenrnnnne nnnnne ennnnne eannnne" + ], + "bbox": [ + 480, + 85, + 852, + 441 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/6379ecd2e53538ddfb89eb5c655662a897ddfedea0c77f885fa2119d8d1e5061.jpg", + "table_caption": [ + "Table 4. Ablation studies on pre-training architectures." + ], + "table_footnote": [], + "table_body": "
Appearance StreamMotion StreamAcc. (%)
A065.85
A1✓70.13
A2 (Ours)✓✓78.25
", + "bbox": [ + 78, + 506, + 468, + 577 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/86069651966d97d4db0c809ed5fa240aa87c87e81a1df3a0a7f470cd3e97d20b.jpg", + "table_caption": [ + "Table 5. Ablation studies on masking ratios." + ], + "table_footnote": [], + "table_body": "
B1B2 (Ours)B3
Masking Ratio65%75%85%
Accuracy (%)76.9178.2577.20
", + "bbox": [ + 78, + 604, + 465, + 661 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "architecture, we first present the performance of model A0 as the $10\\%$ NTU-RGBD baseline in a fully supervised manner $(65.85\\%)$ . Then, model A1 is developed by removing the motion prediction stream. Quantitative results are presented in Table 4. It shows that with solely the appearance stream, the performance gain introduced by model A1 pretraining is limited. When these two streams are combined, comprehensive information can be learned and superior accuracy is achieved by our model A2 $(65.85\\% \\rightarrow 78.25\\%)$ . This demonstrates the effectiveness of our mask-based pretraining on point cloud videos and the necessity of the task of explicitly predicting motions.", + "bbox": [ + 75, + 688, + 468, + 868 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Masking Ratio. The masking operation plays a critical role in our MaST-Pre. Therefore, we conduct experiments", + "bbox": [ + 75, + 869, + 468, + 900 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/de1293a0174bf77d428a350fc5b62491c9fa7b767324c56449cf9e0d84ebb734.jpg", + "table_caption": [ + "Table 6. Ablation studies on the appearance stream." + ], + "table_footnote": [], + "table_body": "
# FramesTemporal & SpatialAccuracy (%)
D11-77.34
D23Coupling58.60
D3 (Ours)3Decoupling78.25
", + "bbox": [ + 501, + 506, + 887, + 583 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "to study different masking ratios, and the results are presented in Table 5. It shows that a high masking ratio is beneficial to our MaST-Pre and the highest accuracy is achieved at $75\\%$ masking ratio (model B2).", + "bbox": [ + 496, + 611, + 890, + 671 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Appearance Stream. Right reconstruction targets in the appearance stream contribute to the performance of our MaST-Pre. For model D3, in each point tube, the reconstruction loss (Eq. 2) is first calculated in each frame separately and then aggregated over $l$ frames, which is a decoupled manner. In contrast, model D2 calculates the reconstruction loss in a coupled manner by considering all points together. We also develop model D1 to reconstruct only the middle frame of each point tube.", + "bbox": [ + 496, + 672, + 892, + 808 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "As shown in Table 6, model D2 brings no accuracy gain and is even worse than the baseline model A0 (58.60% vs. 65.85%). In addition, D3 outperforms D1 and D2. This is because D3 implicitly learns spatio-temporal information during the process of reconstructing decoupled point tubes. We further visualize the reconstruction results in Fig. 4.", + "bbox": [ + 496, + 810, + 893, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "16586", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1dc66e7b855c05ca16fddd4bb1ec50c13c11297491aa996f499b40007da396a3.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 99, + 89, + 351, + 279 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/e7150fb7486695d9870fe7efc64d989efa51cfde878394dbc3a2a08efb0a10c0.jpg", + "image_caption": [ + "Figure 5. Samples of temporal cardinality difference, computed by subtracting cardinality histograms of frame $t - 1$ from frame $t$ ." + ], + "image_footnote": [], + "bbox": [ + 99, + 282, + 140, + 297 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Frame t-1", + "bbox": [ + 142, + 285, + 197, + 295 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/8c5d604dc5668e452de5a32e3f60b58970772c66f04550cd887059df5e0ddf5d.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 214, + 282, + 245, + 297 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Frame $t$", + "bbox": [ + 251, + 286, + 295, + 295 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/62d965fd48f312bb9a034fc9fdce71491efc0c1bd33ba73bbbaebf1fb1305fd6.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 315, + 286, + 349, + 297 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Movement", + "bbox": [ + 352, + 287, + 415, + 296 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/b22d679be37653c6d254f32dcef9740ae31264fc409eecf7f701923503850eea.jpg", + "image_caption": [ + "(b) Putting Hands Down" + ], + "image_footnote": [], + "bbox": [ + 403, + 90, + 614, + 260 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Key Point", + "bbox": [ + 431, + 285, + 498, + 296 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Support Domain", + "bbox": [ + 535, + 285, + 629, + 296 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/057e03f0ae59c4725d190ae9cd8f4dc530050dcae4605c7be33a3574e2ee23a2.jpg", + "image_caption": [ + "(c) Kicking Forward" + ], + "image_footnote": [], + "bbox": [ + 640, + 92, + 874, + 258 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/28a411feced4c81fa9bb4bf3148c3ccf3b7bbdafd39aba34a2114c4b8853afae.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 643, + 280, + 870, + 301 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/b9294ae5bc2021484ebcd535153f41a2a34ae896564027980534ba309281114d.jpg", + "table_caption": [ + "Table 7. Ablation studies on the temporal cardinality difference." + ], + "table_footnote": [], + "table_body": "
E1E2 (Ours)E3
# Section4816
Accuracy (%)77.8578.2569.50
", + "bbox": [ + 86, + 344, + 367, + 401 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/06b3d46cad289275d4bd66e8f1bd4ae27d88ee85b2ce2e514a99c9d3e4ab68a2.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
F1F2 (Ours)
InterpolationX✓
Accuracy (%)76.6978.25
", + "bbox": [ + 385, + 345, + 616, + 401 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/920ba76df114a5871eb8ba03a448c9ba984c8043e40181f4b64e619e5eb4ef10.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
G1 (Ours)G2
# Stride12
Accuracy (%)78.2575.85
", + "bbox": [ + 633, + 345, + 867, + 401 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Temporal Cardinality Difference. In order to investigate the temporal cardinality difference, we present the results under different sections, interpolations, and strides in Table 7. We develop the model E1/E3 to divide the support domain into 4/16 sections, while their accuracy is lower than E2 with 8 sections. This is because small space resolution will introduce noises and large resolution makes temporal cardinality difference insensitive to motions.", + "bbox": [ + 75, + 426, + 468, + 547 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Next, we develop model F1 by removing interpolation. While F2 outperforms F1 because interpolation improves its robustness. Finally, we develop model G2 to calculate the cardinality difference with temporal stride 2, but its performance is worse than G1 with stride 1. This is because a large temporal stride cannot capture fine-grained motions.", + "bbox": [ + 75, + 549, + 468, + 641 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We further visualize multiple samples of temporal cardinality difference in Fig. 5 to demonstrate its effectiveness in modeling motions. We present three typical actions, each consisting of two samples. As shown in Fig. 5(a), the temporal cardinality differences of the two raising hands actions project extremely similar motion patterns. Points in the first and seventh octants flow out heavily over time. Meanwhile, temporal cardinality differences within putting hands down (Fig. 5(b)) also display similarities, as well as in kicking forward (Fig. 5(c)). In particular, the temporal cardinality differences between raising hands and putting hands down are approximately reversible, which reflects its effectiveness in modeling dynamics.", + "bbox": [ + 75, + 642, + 468, + 838 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Computational Complexity. Table 8 shows the pretraining complexity and corresponding fine-tuning accuracy of the two models. After adding the motion prediction stream, model H2 achieves much higher accuracy than", + "bbox": [ + 75, + 839, + 468, + 900 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/ee71fe7f13f5ec83809ff58578a43de341de4a204b0834d0e93850ea5f9610eb.jpg", + "table_caption": [ + "Table 8. Time (mins/epoch) and memory (MiB) complexities." + ], + "table_footnote": [], + "table_body": "
ArchitecturesEncoderTimeMemoryAcc. (%)
H1Only Appearancew/o [M]5.4641470.13
H2 (Ours)Two Streamsw/o [M]6.2641878.25
", + "bbox": [ + 501, + 436, + 888, + 494 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "H1 with only a minor increase in pre-training complexities $(70.13\\% \\rightarrow 78.25\\%)$ .", + "bbox": [ + 498, + 522, + 890, + 551 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 570, + 617, + 585 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this paper, we introduce a masked spatio-temporal structure prediction method for point cloud video pretraining, termed as MaST-Pre. For modeling subtle dynamics, the temporal cardinality difference is proposed, which can be calculated online directly from inputs. Based on point-tube masking, MaST-Pre jointly conducts point cloud video reconstruction and temporal cardinality difference prediction to learn both appearance and motion information. Experiments on four benchmarks show that our MaST-Pre is an effective pre-training framework to boost the performance of point cloud video understanding.", + "bbox": [ + 496, + 597, + 890, + 763 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgments. This work was partially supported by the Fundamental Research Funds for the Central Universities (No. 226-2023-00048), the National Natural Science Foundation of China (No. U20A20185, 61972435), the Guangdong Basic and Applied Basic Research Foundation (2022B1515020103), the Shenzhen Science and Technology Program (No. RCYX20200714114641140), and the Chongqing Technology Innovation and Application Development Special Key Project(cstc2021jscx-cylhX0006).", + "bbox": [ + 496, + 763, + 890, + 901 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "16587", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lučić, and Cordelia Schmid. Vivit: A video vision transformer. In ICCV, 2021. 4", + "[2] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. BEiT: BERT pre-training of image transformers. In ICLR, 2022. 2", + "[3] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, Sandhini Agarwal, Ariel Herbert-Voss, Gretchen Krueger, Tom Henighan, Rewon Child, Aditya Ramesh, Daniel Ziegler, Jeffrey Wu, Clemens Winter, Chris Hesse, Mark Chen, Eric Sigler, Mateusz Litwin, Scott Gray, Benjamin Chess, Jack Clark, Christopher Berner, Sam McCandlish, Alec Radford, Ilya Sutskever, and Dario Amodei. Language models are few-shot learners. In NeurIPS, 2020. 2", + "[4] Mark Chen, Alec Radford, Rewon Child, Jeffrey Wu, Heewoo Jun, David Luan, and Ilya Sutskever. Generative pretraining from pixels. In ICML, 2020. 2", + "[5] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning of visual representations. In ICML, 2020. 1", + "[6] Christopher Choy, JunYoung Gwak, and Silvio Savarese. 4D spatio-temporal convnets: Minkowski convolutional neural networks. In CVPR, 2019. 1", + "[7] Quentin De Smedt, Hazem Wannous, Jean-Philippe Vandeborre, Joris Guerry, Bertrand Le Saux, and David Filiat. SHREC'17 Track: 3D hand gesture recognition using a depth and skeletal dataset. In 3DOR, 2017. 5", + "[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In ICLR, 2021. 2", + "[9] Hehe Fan, Yi Yang, and Mohan Kankanhalli. Point 4D transformer networks for spatio-temporal modeling in point cloud videos. In CVPR, 2021. 1, 2, 3, 4, 5, 6", + "[10] Hehe Fan, Yi Yang, and Mohan Kankanhalli. Point spatiotemporal transformer networks for point cloud video modeling. IEEE Transactions on Pattern Analysis and Machine Intelligence, 45(2):2181-2192, 2022. 1, 3, 5, 6", + "[11] Hehe Fan, Xin Yu, Yuhang Ding, Yi Yang, and Mohan Kankanhalli. PSTNet: Point spatio-temporal convolution on point cloud sequences. In ICLR, 2021. 1, 2, 3, 5, 6", + "[12] Hehe Fan, Xin Yu, Yi Yang, and Mohan Kankanhalli. Deep hierarchical representation of point cloud videos via spatio-temporal decomposition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(12):9918-9930, 2021. 1, 3, 5, 6", + "[13] Christoph Feichtenhofer, Haoqi Fan, Yanghao Li, and Kaiming He. Masked autoencoders as spatiotemporal learners. NeurIPS, 2022. 2, 4, 5, 6", + "[14] Basura Fernando, Efstratios Gavves, José Oramas, Amir Ghodrati, and Tinne Tuytelaars. Rank pooling for action recognition. IEEE transactions on pattern analysis and machine intelligence, 39(4):773-787, 2016. 3" + ], + "bbox": [ + 78, + 114, + 467, + 898 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[15] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In CVPR, 2022. 1, 2, 4, 5, 6", + "[16] Kaiming He, Haoqi Fan, Yuxin Wu, Saining Xie, and Ross Girshick. Momentum contrast for unsupervised visual representation learning. In CVPR, 2020. 1", + "[17] Ji Hou, Benjamin Graham, Matthias Nießner, and Saining Xie. Exploring data-efficient 3D scene understanding with contrastive scene contexts. In CVPR, 2021. 2", + "[18] Siyuan Huang, Yichen Xie, Song-Chun Zhu, and Yixin Zhu. Spatio-temporal self-supervised representation learning for 3D point clouds. In ICCV, 2021. 2", + "[19] Jacob Devlin Ming-Wei Chang Kenton and Lee Kristina Toutanova. BERT: Pre-training of deep bidirectional transformers for language understanding. In NAACL, 2019. 1, 2", + "[20] Wanqing Li, Zhengyou Zhang, and Zicheng Liu. Action recognition based on a bag of 3D points. In CVPRW, 2010. 5", + "[21] Hanxue Liang, Hehe Fan, Zhiwen Fan, Yi Wang, Tianlong Chen, Yu Cheng, and Zhangyang Wang. Point cloud domain adaptation via masked local 3D structure prediction. In ECCV, 2022. 2", + "[22] Haotian Liu, Mu Cai, and Yong Jae Lee. Masked discrimination for self-supervised learning on point clouds. In ECCV, 2022. 2", + "[23] Xingyu Liu, Charles R Qi, and Leonidas J Guibas. Flownet3D: Learning scene flow in 3D point clouds. In CVPR, 2019. 3", + "[24] Xingyu Liu, Mengyuan Yan, and Jeannette Bohg. MeteorNet: Deep learning on dynamic 3D point cloud sequences. In ICCV, 2019. 1, 3, 5", + "[25] Ze Liu, Jia Ning, Yue Cao, Yixuan Wei, Zheng Zhang, Stephen Lin, and Han Hu. Video swim transformer. In CVPR, 2022. 4", + "[26] Yuecong Min, Xiujuan Chai, Lei Zhao, and Xilin Chen. FlickerNet: Adaptive 3D gesture recognition from sparse point clouds. In BMVC, 2019. 6", + "[27] Yuecong Min, Yanxiao Zhang, Xiujuan Chai, and Xin Chen. An efficient PointLSTM for point clouds based gesture recognition. In CVPR, 2020. 5, 6", + "[28] Pavlo Molchanov, Xiaodong Yang, Shalini Gupta, Kihwan Kim, Stephen Tyree, and Jan Kautz. Online detection and classification of dynamic hand gestures with recurrent 3D convolutional neural network. In CVPR, 2016. 5", + "[29] Yatian Pang, Wenxiao Wang, Francis E.H. Tay, Wei Liu, Yonghong Tian, and Li Yuan. Masked autoencoders for point cloud self-supervised learning. In ECCV, 2022. 2, 3", + "[30] Helmut Pottmann and Johannes Wallner. Computational line geometry. Springer, 2001. 3", + "[31] Rui Qian, Shuangrui Ding, Xian Liu, and Dahua Lin. Static and dynamic concepts for self-supervised video representation learning. In ECCV, 2022. 4", + "[32] Yongming Rao, Jiwen Lu, and Jie Zhou. Global-local bidirectional reasoning for unsupervised representation learning of 3D point clouds. In CVPR, 2020. 2" + ], + "bbox": [ + 501, + 92, + 890, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "16588", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[33] Amir Shahroudy, Jun Liu, Tian-Tsong Ng, and Gang Wang. NTU RGB+D: A large scale dataset for 3D human activity analysis. In CVPR, 2016. 5", + "[34] Zhiqiang Shen, Xiaoxiao Sheng, Longguang Wang, Yulan Guo, Qiong Liu, and Xi Zhou. Pointemp: Contrastive mask prediction for self-supervised learning on point cloud videos. In CVPR, 2023. 3", + "[35] Xiaoxiao Sheng, Zhiqiang Shen, and Gang Xiao. Contrastive predictive autoencoders for dynamic point cloud self-supervised learning. In AAAI, 2023. 3", + "[36] Karen Simonyan and Andrew Zisserman. Two-stream convolutional networks for action recognition in videos. In NeurIPS, 2014. 4", + "[37] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. VideoMAE: Masked autoencoders are data-efficient learners for self-supervised video pre-training. In NeurIPS, 2022. 2, 4, 5", + "[38] Haiyan Wang, Liang Yang, Xuejian Rong, Jinglun Feng, and Yingli Tian. Self-supervised 4D spatio-temporal feature learning via order prediction of sequential point cloud clips. In WACV, 2021. 3", + "[39] Rui Wang, Dongdong Chen, Zuxuan Wu, Yinpeng Chen, Xiyang Dai, Mengchen Liu, Yu-Gang Jiang, Luowei Zhou, and Lu Yuan. BEVT: BERT pretraining of video transformers. In CVPR, 2022. 2", + "[40] Yancheng Wang, Yang Xiao, Fu Xiong, Wenxiang Jiang, Zhiguo Cao, Joey Tianyi Zhou, and Junsong Yuan. 3DV: 3D dynamic voxel for action recognition in depth video. In CVPR, 2020. 1, 3, 6", + "[41] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In CVPR, 2022. 2", + "[42] Yimin Wei, Hao Liu, Tingting Xie, Qiuhong Ke, and Yulan Guo. Spatial-temporal transformer for 3D point cloud sequences. In WACV, 2022. 1, 3", + "[43] Hao Wen, Yunze Liu, Jingwei Huang, Bo Duan, and Li Yi. Point primitive transformer for long-term 4D point cloud video understanding. In ECCV, 2022. 1, 3, 5", + "[44] Saining Xie, Jiatao Gu, Demi Guo, Charles R Qi, Leonidas Guibas, and Or Litany. PointContrast: Unsupervised pretraining for 3D point cloud understanding. In ECCV, 2020. 2", + "[45] Zhenda Xie, Zheng Zhang, Yue Cao, Yutong Lin, Jianmin Bao, Zhuliang Yao, Qi Dai, and Han Hu. SimMIM: A simple framework for masked image modeling. In CVPR, 2022. 2", + "[46] Yaoqing Yang, Chen Feng, Yiru Shen, and Dong Tian. FoldingNet: Point cloud auto-encoder via deep grid deformation. In CVPR, 2018. 2", + "[47] Xumin Yu, Lulu Tang, Yongming Rao, Tiejun Huang, Jie Zhou, and Jiwen Lu. Point-BERT: Pre-training 3D point cloud transformers with masked point modeling. In CVPR, 2022. 2, 3", + "[48] Zhuoyang Zhang, Yuhao Dong, Yunze Liu, and Li Yi. Complete-to-partial 4D distillation for self-supervised point cloud sequence representation learning. arXiv preprint arXiv:2212.05330, 2022. 3" + ], + "bbox": [ + 78, + 90, + 468, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[49] Zaiwei Zhang, Rohit Girdhar, Armand Joulin, and Ishan Misra. Self-supervised pretraining of 3D features on any point-cloud. In ICCV, 2021. 2", + "[50] Jia-Xing Zhong, Kaichen Zhou, Qingyong Hu, Bing Wang, Niki Trigoni, and Andrew Markham. No Pain, Big Gain: Classify dynamic point cloud sequences with static models by fitting feature-level space-time surfaces. In CVPR, 2022. 1, 3, 5, 6" + ], + "bbox": [ + 501, + 90, + 890, + 203 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "16589", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/e14b4021-babf-4da5-a112-3aa5b237ce50_model.json b/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/e14b4021-babf-4da5-a112-3aa5b237ce50_model.json new file mode 100644 index 0000000000000000000000000000000000000000..124c309f3d91f7b5e43e79bb582c2cd7c14d691b --- /dev/null +++ b/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/e14b4021-babf-4da5-a112-3aa5b237ce50_model.json @@ -0,0 +1,2387 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.105, + 0.13, + 0.868, + 0.175 + ], + "angle": 0, + "content": "Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos" + }, + { + "type": "text", + "bbox": [ + 0.123, + 0.203, + 0.85, + 0.275 + ], + "angle": 0, + "content": "Zhiqiang Shen\\(^{1,5*}\\), Xiaoxiao Sheng\\(^{1*}\\), Hehe Fan\\(^{2\\dagger}\\), Longguang Wang\\(^{3}\\), Yulan Guo\\(^{4}\\), Qiong Liu\\(^{5}\\), Hao Wen\\(^{5}\\), Xi Zhou\\(^{1,5}\\) \n\\(^{1}\\)Shanghai Jiao Tong University \\(^{2}\\)Zhejiang University \\(^{3}\\)Aviation University of Air Force \\(^{4}\\)Sun Yat-sen University \\(^{5}\\)CloudWalk" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.309, + 0.314, + 0.327 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.342, + 0.474, + 0.691 + ], + "angle": 0, + "content": "Recently, the community has made tremendous progress in developing effective methods for point cloud video understanding that learn from massive amounts of labeled data. However, annotating point cloud videos is usually notoriously expensive. Moreover, training via one or only a few traditional tasks (e.g., classification) may be insufficient to learn subtle details of the spatio-temporal structure existing in point cloud videos. In this paper, we propose a Masked Spatio-Temporal Structure Prediction (MaST-Pre) method to capture the structure of point cloud videos without human annotations. MaST-Pre is based on spatio-temporal point-tube masking and consists of two self-supervised learning tasks. First, by reconstructing masked point tubes, our method is able to capture the appearance information of point cloud videos. Second, to learn motion, we propose a temporal cardinality difference prediction task that estimates the change in the number of points within a point tube. In this way, MaST-Pre is forced to model the spatial and temporal structure in point cloud videos. Extensive experiments on MSRAction-3D, NTU-RGBD, NvGesture, and SHREC'17 demonstrate the effectiveness of the proposed method. The code is available at https://github.com/JohnsonSign/MaST-Pre." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.718, + 0.21, + 0.735 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.744, + 0.47, + 0.866 + ], + "angle": 0, + "content": "In physics, motion is the phenomenon in which position changes over time. Because point clouds provide precise position information, i.e., 3D coordinates, point cloud videos, which evolve over time, can accurately describe the 3D motion in the real world. Effectively understanding point cloud videos can significantly improve intelligent agents on the interaction with environments. Therefore, the community has developed a few effective methods for" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.309, + 0.889, + 0.527 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.531, + 0.895, + 0.603 + ], + "angle": 0, + "content": "Figure 1. Our MaST-Pre is based on spatio-temporal point-tube masking. To enable a model to capture the appearance structure in point cloud videos, we ask it to reconstruct masked point tubes. To equip the model with motion modeling ability, we develop a temporal cardinality difference prediction task." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.628, + 0.895, + 0.794 + ], + "angle": 0, + "content": "point cloud video understanding, including video classification [9-12, 40, 50] and semantic segmentation [6, 24, 42, 43]. However, most of these methods are based on supervised learning and that requires much effort to carefully annotate massive amounts of labels. Moreover, learning via only classification or segmentation may make deep neural networks take too much emphasis on the task itself but largely ignore the subtle details of the instinct spatiotemporal structure in point cloud videos. To alleviate those problems, we propose a self-supervised learning method on point cloud videos." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.896, + 0.903 + ], + "angle": 0, + "content": "Self-supervised learning uses supervisory signals from the data itself and enables deep neural networks to learn from massive data without human annotations. This is important to recognize more subtle patterns in data. Networks pre-trained with self-supervised learning usually yield higher performance than when solely trained in a supervised manner [5, 15, 16, 19]. Although self-supervised" + }, + { + "type": "page_footnote", + "bbox": [ + 0.095, + 0.875, + 0.285, + 0.888 + ], + "angle": 0, + "content": "*These authors contributed equally." + }, + { + "type": "page_footnote", + "bbox": [ + 0.098, + 0.888, + 0.223, + 0.9 + ], + "angle": 0, + "content": "† Corresponding author." + }, + { + "type": "list", + "bbox": [ + 0.095, + 0.875, + 0.285, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "16580" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.212 + ], + "angle": 0, + "content": "learning has been applied to images [15], videos [13, 37] and static point clouds [29, 47], it has not been promoted on 4D signals, such as point cloud videos. Visual signals in point cloud videos can be divided into appearance and motion. While appearance specifies which objects are in videos, motion describes their dynamics. Therefore, self-supervised learning on point cloud videos should carefully make the most of the appearance and motion structure." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.214, + 0.471, + 0.426 + ], + "angle": 0, + "content": "In this paper, we propose a Masked Spatio-Temporal Structure Prediction (MaST-Pre) method for self-supervised learning on point cloud videos (Fig. 1). MaST-Pre is based on a masking strategy, which has been proven effective in a range of applications. For example, because of the canonical structure, images can be easily segmented into multiple patches for masking [8, 15], which in the case of video are extended to patch tubes [13, 37]. For unstructured static point clouds, spherical support domain masking can be used for masked autoencoder [29, 47]. However, the spatial irregularity and temporal regularity make point cloud videos require a more elaborate masking strategy. Our method is based on a masked point tube mechanism, where a point tube is a local area expanding over a short time [11]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.427, + 0.471, + 0.669 + ], + "angle": 0, + "content": "Based on point-tube masking, our MaST-Pre employs two self-supervised tasks to capture the appearance and motion structure, respectively. First, to learn the appearance structure, MaST-Pre is asked to predict the invisible parts of the input from unmasked points. Second, to capture the dynamics in point tubes, we propose the temporal cardinality difference, which can be calculated online from inputs without additional parameters. Cardinality can reflect basic structures (e.g., line, edge, and plane) of static point clouds [21]. In this paper, we extend it to a temporal version so that it can model the dynamics of point cloud videos. Intuitively, the temporal cardinality difference characterizes the flow of points within a short time. Therefore, inferring the temporal cardinality difference of masked point tubes facilitates MaST-Pre to learn motion-informative representations. Our contributions are summarized as follows:" + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.685, + 0.469, + 0.747 + ], + "angle": 0, + "content": "- We design a 4D scheme of masked prediction for self-supervised learning on point cloud videos, termed as MaST-Pre. Our MaST-Pre jointly learns the appearance and motion structure of point cloud videos." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.761, + 0.469, + 0.822 + ], + "angle": 0, + "content": "- We propose the temporal cardinality difference, a simple and effective motion feature directly captured from raw input points. It explicitly guides MaST-Pre to learn motion-informative representations." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.837, + 0.469, + 0.882 + ], + "angle": 0, + "content": "- Extensive experiments and ablation studies on several benchmark datasets validate that our MaST-Pre learns rich representations of point cloud videos." + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.685, + 0.469, + 0.882 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.09, + 0.642, + 0.107 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.115, + 0.892, + 0.177 + ], + "angle": 0, + "content": "In this section, we first briefly review visual mask prediction for self-supervised learning. Then, we present recent advances in self-supervised learning on point clouds and dynamics modeling for point cloud videos." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.183, + 0.719, + 0.198 + ], + "angle": 0, + "content": "2.1. Visual Mask Prediction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.206, + 0.892, + 0.342 + ], + "angle": 0, + "content": "Mask prediction has been proven to be an excellent self-supervised task for visual representation learning [8,15,45]. By reconstructing target signals from the masked input, mask prediction enables the network to learn rich representations and boosts self-supervised learning [2,4,39,41]. Chen et al. [4] extended GPT [3] to operate the pixel sequence for prediction. Bao et al. [2] and Wang et al. [39] introduced another successful framework, BERT [19], to predict the identities of masked tokens." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.342, + 0.893, + 0.555 + ], + "angle": 0, + "content": "Then, He et al. [15] proposed MAE as a scalable vision learner to predict the pixels of masked patches. Feichtenhofer et al. [13] and Tong et al. [37] extended MAE to video representation learning by masking patch tubes. Wei et al. [41] developed MaskFeat to predict the HOG features of masked spatio-temporal tubes for self-supervised video pretraining. The regular structure of images and videos makes it easy to obtain patches or patch tubes, which facilitates the design of masking strategies. Pang et al. [29] extended MAE to unstructured static point clouds and designed a masking strategy based on the local spatial neighborhoods. However, point cloud videos are not only spatially irregular but also temporally misaligned across frames [9, 11]. To remedy this, we design a point-tube masking strategy." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.561, + 0.855, + 0.577 + ], + "angle": 0, + "content": "2.2. Self-supervised Learning on Point Clouds" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.585, + 0.892, + 0.827 + ], + "angle": 0, + "content": "Contrastive learning has made significant progress on static point clouds [17, 32, 44, 49]. Xie et al. [44] proposed PointContrast to discriminate two geometric views of matched points using contrastive loss. Hou et al. [17] introduced contextual contrastive learning to PointContrast for data-efficient point pre-training. Rao et al. [32] mapped the local and global features to shared representation space and applied a contrastive loss on them. Zhang et al. [49] used the instance discrimination task on two augmented versions of a point cloud, while Huang et al. [18] pre-trained static point clouds using spatio-temporal augmentations. They transformed different views at point, region, object, and scene levels, and then used contrastive learning to judge their semantic consistency. However, there are limited augmentation methods that can guarantee the semantic consistency of point clouds, let alone point cloud videos." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Prediction-based methods on point clouds also attract a lot of attention. Yang et al. [46] proposed a folding-based autoencoder that deforms a 2D grid to reconstruct the target 3D point cloud. Recently, mask prediction has been extended to static point clouds. Liu et al. [22] designed a point" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "16581" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.096, + 0.089, + 0.874, + 0.301 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.307, + 0.893, + 0.351 + ], + "angle": 0, + "content": "Figure 2. Illustration of the proposed MaST-Pre method. First, given a point cloud video, MaST-Pre divides it into several point tubes and masks part of them. Then, based on an encoder-decoder architecture, MaST-Pre attempts to recover masked point tubes and predict their temporal cardinality difference." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.374, + 0.473, + 0.51 + ], + "angle": 0, + "content": "discrimination task for masked patches. Yu et al. [47] proposed PointBERT with an offline point tokenizer. Pang et al. [29] used a simpler task, reconstructing masked point coordinates, for point pre-training in an end-to-end manner. However, these methods solely focus on the geometric representation learning of static point clouds. In this paper, on top of learning appearance information, an explicit motion information learning method is designed for point cloud videos." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.526, + 0.446, + 0.543 + ], + "angle": 0, + "content": "2.3. Dynamics Modeling for Point Cloud Videos" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.552, + 0.47, + 0.763 + ], + "angle": 0, + "content": "Supervised learning dominates point cloud video research. [11, 12] and [9, 10, 42, 43] use convolution-based methods and attention-based methods to implicitly learn the long-term features of point cloud videos, respectively. In addition, [24, 40, 50] apply empirical-based dynamics methods modeling point cloud videos. Wang et al. [40] introduced temporal rank pooling [14] to capture the frame-level dynamics. Zhong et al. [50] proposed a two-stream framework and used feature-level ST-surfaces [30] in the dynamics learning branch. Liu et al. [24] used a scene flow estimator [23] or an alternative grouping method to do point tracking for dynamics modeling. Although these methods are effective, they require complex calculations or additional modules." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Self-supervised learning on point cloud videos is understudied [34, 35]. Wang et al. [38] pre-trained the encoder by predicting the temporal order of shuffled segments to learn the dynamics of point cloud videos. Zhang et al. [48] developed complete-to-partial 4D distillation to predict the representations of point cloud frames within a short time window. However, these methods learn motion information using clip-level or frame-level pretext tasks. In this paper, we propose the temporal cardinality difference prediction" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.375, + 0.879, + 0.39 + ], + "angle": 0, + "content": "for fine-grained dynamics learning on point cloud videos." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.403, + 0.591, + 0.419 + ], + "angle": 0, + "content": "3. Method" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.429, + 0.892, + 0.626 + ], + "angle": 0, + "content": "The architecture of our MaST-Pre is illustrated in Fig. 2. Given a point cloud video, it is first divided into multiple point tubes. Next, a masking operation is performed, separating these point tubes into visible and invisible parts. The visible ones are fed to an encoder, and then their updated embeddings are fed to the decoder along with the masked point tubes. Afterward, two-stream prediction tasks are implemented to recover the point coordinates within masked point tubes and to infer their temporal cardinality differences, respectively. Intuitively, enabling the decoder to perform well on two-stream prediction tasks demands the encoder to learn representations rich in appearance and motion information jointly." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.636, + 0.673, + 0.652 + ], + "angle": 0, + "content": "3.1. Masking Strategy" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.659, + 0.89, + 0.689 + ], + "angle": 0, + "content": "The masking strategy includes three steps: input division, embedding, and masking operation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.69, + 0.892, + 0.87 + ], + "angle": 0, + "content": "Division. Point tubes are introduced as division units of the input point cloud video. Specifically, given a point cloud video \\( \\pmb{P} \\), Farthest Point Sampling is used to select \\( N \\) key points \\( \\hat{\\pmb{p}} \\) from the input. Next, we construct one point tube for each key point. The point tube centered at \\( i \\)-th key point \\( \\hat{p}_i \\) is denoted as \\( \\pmb{T}\\pmb{u}\\pmb{e}_{\\hat{p}_i} = \\{p \\mid p \\in \\pmb{P}, \\mathcal{D}_s(p, \\hat{p}_i) < r, \\mathcal{D}_t(p, \\hat{p}_i) < \\frac{l}{2}\\} \\), where \\( p \\) is one of the input points, \\( \\mathcal{D}_s \\) is the Euclidean distance, \\( \\mathcal{D}_t \\) is the difference in frame timestamps of two points, \\( r \\) is the radius of a spatial neighborhood and \\( l \\) is the number of frames in a point tube. Then, we use random sampling to select \\( n \\) points in each spatial neighborhood." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "In this way, a point cloud video is divided into \\(N\\) point tubes, and each point tube contains \\(l \\times n\\) points. To en" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16582" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.089, + 0.511, + 0.309 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.223, + 0.314, + 0.395, + 0.329 + ], + "angle": 0, + "content": "(a) Cardinality Histogram" + }, + { + "type": "image_footnote", + "bbox": [ + 0.102, + 0.344, + 0.19, + 0.357 + ], + "angle": 0, + "content": "I \\(\\sim\\) VIII Octant" + }, + { + "type": "image_footnote", + "bbox": [ + 0.218, + 0.345, + 0.256, + 0.356 + ], + "angle": 0, + "content": "-·-·" + }, + { + "type": "image_footnote", + "bbox": [ + 0.262, + 0.346, + 0.282, + 0.356 + ], + "angle": 0, + "content": "Oct" + }, + { + "type": "image_footnote", + "bbox": [ + 0.288, + 0.346, + 0.381, + 0.357 + ], + "angle": 0, + "content": "ant Central Line" + }, + { + "type": "image_footnote", + "bbox": [ + 0.413, + 0.346, + 0.449, + 0.356 + ], + "angle": 0, + "content": "#" + }, + { + "type": "image_footnote", + "bbox": [ + 0.455, + 0.346, + 0.499, + 0.356 + ], + "angle": 0, + "content": "Points" + }, + { + "type": "image", + "bbox": [ + 0.533, + 0.09, + 0.889, + 0.309 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.591, + 0.314, + 0.833, + 0.329 + ], + "angle": 0, + "content": "(b) Temporal Cardinality Difference" + }, + { + "type": "image_footnote", + "bbox": [ + 0.535, + 0.345, + 0.591, + 0.358 + ], + "angle": 0, + "content": "\\(d_{1}d_{2}d_{3}d_{4}\\)" + }, + { + "type": "image_footnote", + "bbox": [ + 0.595, + 0.345, + 0.841, + 0.358 + ], + "angle": 0, + "content": "Angular Distance to Octant Central Line" + }, + { + "type": "image_caption", + "bbox": [ + 0.212, + 0.373, + 0.757, + 0.387 + ], + "angle": 0, + "content": "Figure 3. Illustration of Cardinality Histogram (a) and Temporal Cardinality Difference (b)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.412, + 0.47, + 0.442 + ], + "angle": 0, + "content": "sure all points are covered by point tubes, \\( r \\) and \\( l \\) are set to maintain a minor overlap between adjacent point tubes." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.442, + 0.469, + 0.472 + ], + "angle": 0, + "content": "**Embedding.** Following our baseline [9], each point tube is encoded into an embedding:" + }, + { + "type": "equation", + "bbox": [ + 0.165, + 0.48, + 0.469, + 0.528 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {E} _ {\\hat {p} _ {i}} = \\sum_ {t = 1} ^ {l} \\sum_ {p \\in \\boldsymbol {T u b e} _ {\\hat {p} _ {i}} ^ {t}} f (p - \\hat {p} _ {i}), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.537, + 0.47, + 0.582 + ], + "angle": 0, + "content": "where \\(\\mathbf{Tube}_{\\hat{p}_i}^t\\) is the \\(t\\)-th frame of the point tube centered at \\(\\hat{p}_i\\) and \\(f(\\cdot)\\) is an MLP-based feature extractor. More details can be found in [9]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.583, + 0.47, + 0.75 + ], + "angle": 0, + "content": "Masking. The design of the masking operation is related to the information redundancy of input [13, 15, 37]. Because of spatio-temporal coherence, the redundancy of the point cloud video is higher than low-dimensional data. Therefore, our MaST-Pre uses a high masking ratio on point cloud videos and the empirical result is \\(75\\%\\). A high ratio is helpful to alleviate information leakage and make reconstruction a meaningful self-supervised task. In addition, our MaST-Pre uses random masking of point tubes. As a spacetime-agnostic method, random masking is more effective than structure-aware strategies [13]." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.757, + 0.221, + 0.773 + ], + "angle": 0, + "content": "3.2. Autoencoding" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.47, + 0.825 + ], + "angle": 0, + "content": "Our autoencoder is based on vanilla Transformers of point cloud videos [9]. An asymmetric encoder-decoder design is introduced to MaST-Pre." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.469, + 0.901 + ], + "angle": 0, + "content": "Encoder. To better capture the dynamics of point cloud videos, joint spatio-temporal attention is adopted [1,25]. In addition, only the visible point tubes with spatio-temporal positional embeddings are fed into the encoder during pretraining." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.412, + 0.895, + 0.518 + ], + "angle": 0, + "content": "Decoder. The decoder is similar to our encoder but a lightweight vanilla Transformer [9]. It takes both encoded point tubes and masked ones as input. By adding a full set of spatio-temporal positional embeddings to all tokens, location clues are provided for self-supervised learning. After decoding, only the embeddings of masked point tubes are fed to the following prediction heads." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.527, + 0.714, + 0.542 + ], + "angle": 0, + "content": "3.3. Two-stream Prediction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.55, + 0.894, + 0.626 + ], + "angle": 0, + "content": "It is demonstrated in [31, 36] that effective video representation integrates appearance and motion information. Therefore, two-stream self-supervised tasks are proposed to explicitly predict motions and reconstruct the appearance of masked point cloud videos." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.626, + 0.894, + 0.688 + ], + "angle": 0, + "content": "Appearance Stream. The reconstruction objectives are the point coordinates of masked point tubes. The \\(l_{2}\\) Chamber Distance loss is used between predictions \\(P_{pre} \\in \\mathbb{R}^{l \\times n \\times 3}\\) and the ground truth \\(P_{gt} \\in \\mathbb{R}^{l \\times n \\times 3}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.524, + 0.698, + 0.892, + 0.8 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {L} _ {a p p} = \\frac {1}{l} \\sum_ {i = 1} ^ {l} \\left\\{\\frac {1}{| \\boldsymbol {P} _ {p r e} ^ {i} |} \\sum_ {a \\in \\boldsymbol {P} _ {p r e} ^ {i}} \\min _ {b \\in \\boldsymbol {P} _ {g t} ^ {i}} \\| a - b \\| _ {2} ^ {2} + \\right. \\tag {2} \\\\ \\left. \\frac {1}{| \\boldsymbol {P} _ {g t} ^ {i} |} \\sum_ {b \\in \\boldsymbol {P} _ {g t} ^ {i}} \\min _ {a \\in \\boldsymbol {P} _ {p r e} ^ {i}} \\| b - a \\| _ {2} ^ {2} \\right\\}. \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.894, + 0.9 + ], + "angle": 0, + "content": "Motion Stream. We propose the temporal cardinality difference as the target of the motion prediction stream. As shown in Fig. 3(a), the spherical support domain of the key point is divided into 8 octants. We follow the conventional rule that the area where the \\( xyz \\)-coordinates are greater than 0 is the first octant I and then increases counterclockwise." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16583" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.287 + ], + "angle": 0, + "content": "Then, count the cardinality of each octant into the corresponding bin of a histogram. To alleviate the noise in real-world point clouds, a probabilistic approach is employed. Specifically, calculate the angular distance \\( d \\) of each point to the central line of its current octant, and divide it by \\( 90^{\\circ} \\) to normalize. For example, the current octant of Point2 (the green one in Fig. 3(a)) is octant III. The angular difference \\( d2 \\) between Point2 and the central dashed line of octant III is \\( 30^{\\circ} \\). Consequently, the probabilities of Point2 belonging to octant IV and III are \\( \\frac{1}{3} \\) (i.e., \\( \\frac{30^{\\circ}}{90^{\\circ}} \\)) and \\( \\frac{2}{3} \\) (i.e., \\( \\frac{60^{\\circ}}{90^{\\circ}} \\)), respectively. In particular, when a point falls on an axis (e.g., the \\( -y \\) axis), its probabilities belonging to octant IV and III are both 0.5." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.289, + 0.473, + 0.426 + ], + "angle": 0, + "content": "Next, as shown in Fig. 3(b), the cardinality histograms \\(C \\in \\mathbb{R}^8\\) between adjacent frames of a point tube are subtracted to obtain its temporal cardinality difference \\(CD \\in \\mathbb{R}^8\\), which constitutes the ground truth \\(M_{gt} \\in \\mathbb{R}^{(l-1) \\times 8}\\) of the motion stream. The decoded embeddings of masked point tubes are passed through a linear layer to obtain the motion prediction \\(M_{pre} \\in \\mathbb{R}^{(l-1) \\times 8}\\). The smooth \\(l_1\\) loss of \\(i\\)-th \\(CD\\) between prediction and ground truth is denoted as \\(\\mathcal{L}_m^i\\). The loss of our motion stream is denoted as \\(\\mathcal{L}_{motion}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.085, + 0.437, + 0.47, + 0.477 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {m} ^ {i} = \\left\\{ \\begin{array}{l l} 0. 5 \\times \\left(M _ {p r e} ^ {i} - M _ {g t} ^ {i}\\right) ^ {2}, & \\text {i f} \\left| M _ {p r e} ^ {i} - M _ {g t} ^ {i} \\right| < 1 \\\\ \\left| M _ {p r e} ^ {i} - M _ {g t} ^ {i} \\right| - 0. 5, & \\text {o t h e r w i s e} \\end{array} , \\right. \\tag {3}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.188, + 0.492, + 0.47, + 0.533 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {m o t i o n}} = \\frac {1}{l - 1} \\sum_ {i = 1} ^ {l - 1} \\mathcal {L} _ {m} ^ {i}. \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.541, + 0.445, + 0.555 + ], + "angle": 0, + "content": "Overall, the total loss of our MaST-Pre is defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.184, + 0.569, + 0.469, + 0.586 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\text {a p p}} + \\mathcal {L} _ {\\text {m o t i o n}}. \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.598, + 0.47, + 0.63 + ], + "angle": 0, + "content": "With both loss terms, our MaST-Pre can simultaneously learn the geometry and dynamics of point cloud videos." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.644, + 0.21, + 0.66 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.669, + 0.47, + 0.759 + ], + "angle": 0, + "content": "Our experiments are conducted on four point cloud video datasets. Following [13, 15, 37], we implement end-to-end fine-tuning, semi-supervised learning, and transfer learning to evaluate the pre-trained MaST-Pre. Afterward, ablation studies are conducted to analyze the design of our MaST-Pre and show the visualization results." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.771, + 0.18, + 0.786 + ], + "angle": 0, + "content": "4.1. Datasets" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.469, + 0.855 + ], + "angle": 0, + "content": "In this paper, to demonstrate the effectiveness of our spatio-temporal representations, we focus on long-term point cloud video tasks, including 4D action recognition and 4D gesture recognition." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.47, + 0.902 + ], + "angle": 0, + "content": "MSRAction-3D [20] and NTU-RGBD [33] are utilized for the action recognition task. (1) MSRAction-3D is comprised of 567 videos in 20 daily actions. The average" + }, + { + "type": "table_caption", + "bbox": [ + 0.525, + 0.088, + 0.866, + 0.101 + ], + "angle": 0, + "content": "Table 1. Action recognition accuracy on MSRAction-3D." + }, + { + "type": "table", + "bbox": [ + 0.503, + 0.102, + 0.892, + 0.263 + ], + "angle": 0, + "content": "
MethodsAccuracy (%)
Supervised LearningMeteorNet [24]88.50
PSTNet [11]91.20
PSTNet++ [12]92.68
Kinet [50]93.27
PPTr [43]92.33
P4Transformer [9]90.94
PST-Transformer [10]93.73
End-to-end Fine-tuningP4Transformer + MaST-Pre91.29
PST-Transformer + MaST-Pre94.08
" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.301, + 0.892, + 0.406 + ], + "angle": 0, + "content": "frame number contained in each video is about 40. Following [9, 10], 270 videos are used as the training set and 297 videos are adopted as the test data. (2) NTU-RGBD consists of 56,880 videos with 60 fine-grained action categories. The frame number of each video is about 30 to 300. Under the cross-subject setting [33], 40,320 training videos and 16,560 test videos are used." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.413, + 0.893, + 0.519 + ], + "angle": 0, + "content": "SHREC'17 [7] and NvGesture [28] are utilized for the gesture recognition task. (1) SHREC'17 is comprised of 2800 videos in 28 gestures. Following [7], this dataset is split into 1960 training videos and 840 test videos. (2) NvGesture consists of 1532 videos with 25 gesture classes. Following [27], 1050 videos are assigned to the training set and the remaining 482 videos to the test set." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.548, + 0.634, + 0.565 + ], + "angle": 0, + "content": "4.2. Pre-training" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.578, + 0.892, + 0.759 + ], + "angle": 0, + "content": "During pre-training, given a point cloud video, 24 frames are densely sampled and 1024 points are selected for each frame. Following [9, 10], the frame sampling stride is set to 2/1 on NTU-RGBD/MSRAction-3D and only random scaling is employed for data augmentation. For division and embedding, the temporal downsampling rate is set to 2 and the temporal kernel size \\( l \\) of each point tube is set to 3. Meanwhile, the spatial downsampling rate is set to 32. The radius of each support domain \\( r \\) is set to 0.1/0.3 on NTU-RGBD/MSRAction-3D and the number of neighbor points \\( n \\) within the spherical query is set to 32. The masking ratio is set to \\( 75\\% \\) unless otherwise specified." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.893, + 0.902 + ], + "angle": 0, + "content": "P4Transformer [9] is utilized as our encoder, which consists of 10/5 layers of vanilla Transformers on NTU-RGBD/MSRAction-3D. The decoder is a 4-layer transformer. To verify the extensibility, PST-Transformer [10] is also used as an encoder on MSRAction-3D. Our MaST-Pre is pre-trained for 200 epochs and linear warmup is utilized for the first 10 epochs. The AdamW optimizer is used with a batch size of 128, and the initial learning rate is set to 0.001 with a cosine decay strategy." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "16584" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.088, + 0.47, + 0.115 + ], + "angle": 0, + "content": "Table 2. Action recognition accuracy (%) on NTU-RGBD under cross-subject setting." + }, + { + "type": "table", + "bbox": [ + 0.078, + 0.115, + 0.47, + 0.276 + ], + "angle": 0, + "content": "
MethodsAcc.
3DV-Motion [40]84.5
3DV-PointNet++ [40]88.8
PSTNet [11]90.5
PSTNet++ [12]91.4
Kinet [50]92.3
P4Transformer [9]90.2
PST-Transformer [10]91.0
P4Transformer + MaST-Pre (End-to-end Fine-tuning)90.8
P4Transformer + MaST-Pre (50% Semi-supervised)87.8
" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.302, + 0.295, + 0.318 + ], + "angle": 0, + "content": "4.3. End-to-end Fine-tuning" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.324, + 0.469, + 0.414 + ], + "angle": 0, + "content": "We first evaluate our MaST-Pre by fine-tuning the pretrained encoder with a new classifier in a supervised manner. End-to-end fine-tuning experiments are conducted on NTU-RGBD and MSRAction-3D, respectively. In each experiment, the same dataset is used for pre-training and fine-tuning." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.415, + 0.469, + 0.626 + ], + "angle": 0, + "content": "MSRAction-3D. During fine-tuning, 24 frames are densely sampled and 2048 points are selected in each frame. Following [11], the spatial search radius is set to 0.7. The model is trained for 50 epochs with a batch size of 12 on 4 GPUs. We use the AdamW optimizer and the initial learning rate is set to 0.001 with a cosine decay strategy. As shown in Table 1, compared with baselines trained in a fully supervised manner, our MaST-Pre introduces accuracy improvements for both P4Transformer and PST-Transformer. According to prior experience, the masked autoencoder needs to be fed a considerable amount of data in the pretraining stage to learn useful knowledge [13, 15]. However, the MSRAction-3D dataset is too small to bring significant improvement." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.627, + 0.469, + 0.763 + ], + "angle": 0, + "content": "NTU-RGBD. The setup of fine-tuning is the same as pre-training, except that the pre-trained model is fine-tuned for 20 epochs with a batch size of 48 on 8 GPUs and the initial learning rate is set to 0.0005. From the end-to-end fine-tuning in Table 2, we can see that our pre-training method introduces an accuracy improvement compared with the baseline. By predicting the spatio-temporal structure, our MaST-Pre learns appearance and motion information during pre-training." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.772, + 0.315, + 0.789 + ], + "angle": 0, + "content": "4.4. Semi-supervised Learning" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.469, + 0.901 + ], + "angle": 0, + "content": "We also evaluate the learned representations using a semi-supervised learning experiment. Specifically, the cross-subject training set of NTU-RGBD is used for pretraining, and then only a \\(50\\%\\) training set is used for finetuning in a supervised manner. The setup of our semi-supervised learning experiment is the same as end-to-end fine-tuning on NTU-RGBD (Sec. 4.3)." + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.088, + 0.892, + 0.114 + ], + "angle": 0, + "content": "Table 3. Gesture recognition accuracy (\\%) on NvGesture (NvG) and SHREC'17 (SHR)." + }, + { + "type": "table", + "bbox": [ + 0.502, + 0.115, + 0.892, + 0.263 + ], + "angle": 0, + "content": "
MethodsNvGSHR
FlickerNet [26]86.3-
PLSTM [27]85.987.6
PLSTM-PSS [27]87.393.1
Kinet [50]89.195.2
P4Transformer [9] (30 Epochs)84.887.5
P4Transformer [9] (50 Epochs)87.791.2
P4Transformer + MaST-Pre (30 Epochs)87.690.2
P4Transformer + MaST-Pre (50 Epochs)89.392.4
" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.289, + 0.892, + 0.365 + ], + "angle": 0, + "content": "From Table 2, we can see that the \\(50\\%\\) semi-supervised result produced by our MaST-Pre achieves comparable performance to the fully supervised baseline even with only limited annotated data. This clearly demonstrates that MaST-Pre learns high-quality representations." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.374, + 0.679, + 0.39 + ], + "angle": 0, + "content": "4.5. Transfer Learning" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.398, + 0.892, + 0.548 + ], + "angle": 0, + "content": "To evaluate the generalization ability of the representations learned by MaST-Pre, we conduct experiments by transferring the pre-trained encoder to other datasets. Specifically, the encoder is first pre-trained on NTU-RGBD following the setup in Sec. 4.2, and then fine-tuned with a new classifier on NvGesture and SHREC'17, respectively. Our transfer experiments are not only cross-dataset but also cross-task, i.e., from action recognition to gesture recognition. We compare our fine-tuned results to the fully supervised baseline in Table 3." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.55, + 0.892, + 0.761 + ], + "angle": 0, + "content": "During fine-tuning, an AdamW optimizer with a batch size of 24 is used, and the initial learning rate is set to 0.002 with a cosine decay strategy. The pre-trained model is fine-tuned for 50 epochs on NvGesture and SHREC'17. As shown in Table 3, our MaST-Pre pre-training facilitates the P4Transformer to produce superior accuracy compared to the fully supervised baseline. Moreover, our MaST-Pre also performs faster convergence. Compared with the baseline without pre-training, significant improvements are achieved after fine-tuning for only 30 epochs (e.g., \\(84.8\\% \\rightarrow 87.6\\%\\) on NvGesture and \\(87.5\\% \\rightarrow 90.2\\%\\) on SHREC'17). This demonstrates that our MaST-Pre has excellent generalization ability across different tasks, facilitating the accuracy improvement of downstream tasks." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.771, + 0.665, + 0.786 + ], + "angle": 0, + "content": "4.6. Ablation Studies" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.795, + 0.892, + 0.855 + ], + "angle": 0, + "content": "In order to balance authority and efficiency, the experiments of ablation studies are conducted on \\(10\\%\\) NTU-RGBD, which contains 4032 training videos and 1656 test videos with category balance." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.9 + ], + "angle": 0, + "content": "Architecture Design. Our MaST-Pre utilizes a two-stream prediction to jointly learn both appearance and motion information. To demonstrate the effectiveness of this" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "16585" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.092, + 0.087, + 0.472, + 0.442 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.482, + 0.087, + 0.853, + 0.442 + ], + "angle": 0, + "content": null + }, + { + "type": "image_footnote", + "bbox": [ + 0.856, + 0.089, + 0.872, + 0.442 + ], + "angle": 0, + "content": "Rnne aenrnnnne nnnnne ennnnne eannnne" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.445, + 0.894, + 0.472 + ], + "angle": 0, + "content": "Figure 4. Visualization of reconstruction results. For each action sample, the ground truth lies in the first row, the masked video lies in the second row, and the result lies in the third row." + }, + { + "type": "table_caption", + "bbox": [ + 0.111, + 0.493, + 0.435, + 0.507 + ], + "angle": 0, + "content": "Table 4. Ablation studies on pre-training architectures." + }, + { + "type": "table", + "bbox": [ + 0.08, + 0.507, + 0.47, + 0.578 + ], + "angle": 0, + "content": "
Appearance StreamMotion StreamAcc. (%)
A065.85
A1✓70.13
A2 (Ours)✓✓78.25
" + }, + { + "type": "table_caption", + "bbox": [ + 0.142, + 0.592, + 0.404, + 0.605 + ], + "angle": 0, + "content": "Table 5. Ablation studies on masking ratios." + }, + { + "type": "table", + "bbox": [ + 0.08, + 0.605, + 0.466, + 0.662 + ], + "angle": 0, + "content": "
B1B2 (Ours)B3
Masking Ratio65%75%85%
Accuracy (%)76.9178.2577.20
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.689, + 0.47, + 0.869 + ], + "angle": 0, + "content": "architecture, we first present the performance of model A0 as the \\(10\\%\\) NTU-RGBD baseline in a fully supervised manner \\((65.85\\%)\\). Then, model A1 is developed by removing the motion prediction stream. Quantitative results are presented in Table 4. It shows that with solely the appearance stream, the performance gain introduced by model A1 pretraining is limited. When these two streams are combined, comprehensive information can be learned and superior accuracy is achieved by our model A2 \\((65.85\\% \\rightarrow 78.25\\%)\\). This demonstrates the effectiveness of our mask-based pretraining on point cloud videos and the necessity of the task of explicitly predicting motions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.871, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Masking Ratio. The masking operation plays a critical role in our MaST-Pre. Therefore, we conduct experiments" + }, + { + "type": "table_caption", + "bbox": [ + 0.542, + 0.493, + 0.848, + 0.507 + ], + "angle": 0, + "content": "Table 6. Ablation studies on the appearance stream." + }, + { + "type": "table", + "bbox": [ + 0.503, + 0.507, + 0.888, + 0.584 + ], + "angle": 0, + "content": "
# FramesTemporal & SpatialAccuracy (%)
D11-77.34
D23Coupling58.60
D3 (Ours)3Decoupling78.25
" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.612, + 0.892, + 0.672 + ], + "angle": 0, + "content": "to study different masking ratios, and the results are presented in Table 5. It shows that a high masking ratio is beneficial to our MaST-Pre and the highest accuracy is achieved at \\(75\\%\\) masking ratio (model B2)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.673, + 0.893, + 0.809 + ], + "angle": 0, + "content": "Appearance Stream. Right reconstruction targets in the appearance stream contribute to the performance of our MaST-Pre. For model D3, in each point tube, the reconstruction loss (Eq. 2) is first calculated in each frame separately and then aggregated over \\( l \\) frames, which is a decoupled manner. In contrast, model D2 calculates the reconstruction loss in a coupled manner by considering all points together. We also develop model D1 to reconstruct only the middle frame of each point tube." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.894, + 0.901 + ], + "angle": 0, + "content": "As shown in Table 6, model D2 brings no accuracy gain and is even worse than the baseline model A0 (58.60% vs. 65.85%). In addition, D3 outperforms D1 and D2. This is because D3 implicitly learns spatio-temporal information during the process of reconstructing decoupled point tubes. We further visualize the reconstruction results in Fig. 4." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "16586" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.101, + 0.09, + 0.352, + 0.28 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.1, + 0.283, + 0.141, + 0.298 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.143, + 0.286, + 0.198, + 0.296 + ], + "angle": 0, + "content": "Frame t-1" + }, + { + "type": "image", + "bbox": [ + 0.215, + 0.284, + 0.246, + 0.298 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.252, + 0.287, + 0.297, + 0.296 + ], + "angle": 0, + "content": "Frame \\(t\\)" + }, + { + "type": "image", + "bbox": [ + 0.316, + 0.287, + 0.351, + 0.299 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.353, + 0.288, + 0.416, + 0.297 + ], + "angle": 0, + "content": "Movement" + }, + { + "type": "image", + "bbox": [ + 0.404, + 0.091, + 0.616, + 0.261 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.447, + 0.264, + 0.582, + 0.275 + ], + "angle": 0, + "content": "(b) Putting Hands Down" + }, + { + "type": "text", + "bbox": [ + 0.432, + 0.286, + 0.499, + 0.297 + ], + "angle": 0, + "content": "Key Point" + }, + { + "type": "text", + "bbox": [ + 0.536, + 0.286, + 0.63, + 0.297 + ], + "angle": 0, + "content": "Support Domain" + }, + { + "type": "image", + "bbox": [ + 0.642, + 0.093, + 0.875, + 0.26 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.718, + 0.264, + 0.825, + 0.276 + ], + "angle": 0, + "content": "(c) Kicking Forward" + }, + { + "type": "image", + "bbox": [ + 0.644, + 0.281, + 0.872, + 0.302 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.101, + 0.306, + 0.867, + 0.321 + ], + "angle": 0, + "content": "Figure 5. Samples of temporal cardinality difference, computed by subtracting cardinality histograms of frame \\( t - 1 \\) from frame \\( t \\)." + }, + { + "type": "table_caption", + "bbox": [ + 0.293, + 0.332, + 0.674, + 0.345 + ], + "angle": 0, + "content": "Table 7. Ablation studies on the temporal cardinality difference." + }, + { + "type": "table", + "bbox": [ + 0.088, + 0.345, + 0.369, + 0.402 + ], + "angle": 0, + "content": "
E1E2 (Ours)E3
# Section4816
Accuracy (%)77.8578.2569.50
" + }, + { + "type": "table", + "bbox": [ + 0.386, + 0.346, + 0.617, + 0.402 + ], + "angle": 0, + "content": "
F1F2 (Ours)
InterpolationX✓
Accuracy (%)76.6978.25
" + }, + { + "type": "table", + "bbox": [ + 0.635, + 0.346, + 0.868, + 0.402 + ], + "angle": 0, + "content": "
G1 (Ours)G2
# Stride12
Accuracy (%)78.2575.85
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.428, + 0.469, + 0.548 + ], + "angle": 0, + "content": "Temporal Cardinality Difference. In order to investigate the temporal cardinality difference, we present the results under different sections, interpolations, and strides in Table 7. We develop the model E1/E3 to divide the support domain into 4/16 sections, while their accuracy is lower than E2 with 8 sections. This is because small space resolution will introduce noises and large resolution makes temporal cardinality difference insensitive to motions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.55, + 0.469, + 0.642 + ], + "angle": 0, + "content": "Next, we develop model F1 by removing interpolation. While F2 outperforms F1 because interpolation improves its robustness. Finally, we develop model G2 to calculate the cardinality difference with temporal stride 2, but its performance is worse than G1 with stride 1. This is because a large temporal stride cannot capture fine-grained motions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.643, + 0.469, + 0.839 + ], + "angle": 0, + "content": "We further visualize multiple samples of temporal cardinality difference in Fig. 5 to demonstrate its effectiveness in modeling motions. We present three typical actions, each consisting of two samples. As shown in Fig. 5(a), the temporal cardinality differences of the two raising hands actions project extremely similar motion patterns. Points in the first and seventh octants flow out heavily over time. Meanwhile, temporal cardinality differences within putting hands down (Fig. 5(b)) also display similarities, as well as in kicking forward (Fig. 5(c)). In particular, the temporal cardinality differences between raising hands and putting hands down are approximately reversible, which reflects its effectiveness in modeling dynamics." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.469, + 0.901 + ], + "angle": 0, + "content": "Computational Complexity. Table 8 shows the pretraining complexity and corresponding fine-tuning accuracy of the two models. After adding the motion prediction stream, model H2 achieves much higher accuracy than" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.425, + 0.866, + 0.438 + ], + "angle": 0, + "content": "Table 8. Time (mins/epoch) and memory (MiB) complexities." + }, + { + "type": "table", + "bbox": [ + 0.502, + 0.438, + 0.889, + 0.495 + ], + "angle": 0, + "content": "
ArchitecturesEncoderTimeMemoryAcc. (%)
H1Only Appearancew/o [M]5.4641470.13
H2 (Ours)Two Streamsw/o [M]6.2641878.25
" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.523, + 0.892, + 0.553 + ], + "angle": 0, + "content": "H1 with only a minor increase in pre-training complexities \\((70.13\\% \\rightarrow 78.25\\%)\\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.571, + 0.619, + 0.587 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.598, + 0.892, + 0.764 + ], + "angle": 0, + "content": "In this paper, we introduce a masked spatio-temporal structure prediction method for point cloud video pretraining, termed as MaST-Pre. For modeling subtle dynamics, the temporal cardinality difference is proposed, which can be calculated online directly from inputs. Based on point-tube masking, MaST-Pre jointly conducts point cloud video reconstruction and temporal cardinality difference prediction to learn both appearance and motion information. Experiments on four benchmarks show that our MaST-Pre is an effective pre-training framework to boost the performance of point cloud video understanding." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Acknowledgments. This work was partially supported by the Fundamental Research Funds for the Central Universities (No. 226-2023-00048), the National Natural Science Foundation of China (No. U20A20185, 61972435), the Guangdong Basic and Applied Basic Research Foundation (2022B1515020103), the Shenzhen Science and Technology Program (No. RCYX20200714114641140), and the Chongqing Technology Innovation and Application Development Special Key Project(cstc2021jscx-cylhX0006)." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "16587" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.115, + 0.468, + 0.156 + ], + "angle": 0, + "content": "[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lučić, and Cordelia Schmid. Vivit: A video vision transformer. In ICCV, 2021. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.157, + 0.468, + 0.186 + ], + "angle": 0, + "content": "[2] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. BEiT: BERT pre-training of image transformers. In ICLR, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.187, + 0.468, + 0.323 + ], + "angle": 0, + "content": "[3] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, Sandhini Agarwal, Ariel Herbert-Voss, Gretchen Krueger, Tom Henighan, Rewon Child, Aditya Ramesh, Daniel Ziegler, Jeffrey Wu, Clemens Winter, Chris Hesse, Mark Chen, Eric Sigler, Mateusz Litwin, Scott Gray, Benjamin Chess, Jack Clark, Christopher Berner, Sam McCandlish, Alec Radford, Ilya Sutskever, and Dario Amodei. Language models are few-shot learners. In NeurIPS, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.325, + 0.468, + 0.367 + ], + "angle": 0, + "content": "[4] Mark Chen, Alec Radford, Rewon Child, Jeffrey Wu, Heewoo Jun, David Luan, and Ilya Sutskever. Generative pretraining from pixels. In ICML, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.368, + 0.468, + 0.409 + ], + "angle": 0, + "content": "[5] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning of visual representations. In ICML, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.41, + 0.468, + 0.45 + ], + "angle": 0, + "content": "[6] Christopher Choy, JunYoung Gwak, and Silvio Savarese. 4D spatio-temporal convnets: Minkowski convolutional neural networks. In CVPR, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.452, + 0.468, + 0.507 + ], + "angle": 0, + "content": "[7] Quentin De Smedt, Hazem Wannous, Jean-Philippe Vandeborre, Joris Guerry, Bertrand Le Saux, and David Filiat. SHREC'17 Track: 3D hand gesture recognition using a depth and skeletal dataset. In 3DOR, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.509, + 0.468, + 0.59 + ], + "angle": 0, + "content": "[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In ICLR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.592, + 0.468, + 0.633 + ], + "angle": 0, + "content": "[9] Hehe Fan, Yi Yang, and Mohan Kankanhalli. Point 4D transformer networks for spatio-temporal modeling in point cloud videos. In CVPR, 2021. 1, 2, 3, 4, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.635, + 0.468, + 0.689 + ], + "angle": 0, + "content": "[10] Hehe Fan, Yi Yang, and Mohan Kankanhalli. Point spatiotemporal transformer networks for point cloud video modeling. IEEE Transactions on Pattern Analysis and Machine Intelligence, 45(2):2181-2192, 2022. 1, 3, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.69, + 0.468, + 0.732 + ], + "angle": 0, + "content": "[11] Hehe Fan, Xin Yu, Yuhang Ding, Yi Yang, and Mohan Kankanhalli. PSTNet: Point spatio-temporal convolution on point cloud sequences. In ICLR, 2021. 1, 2, 3, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.733, + 0.468, + 0.801 + ], + "angle": 0, + "content": "[12] Hehe Fan, Xin Yu, Yi Yang, and Mohan Kankanhalli. Deep hierarchical representation of point cloud videos via spatio-temporal decomposition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(12):9918-9930, 2021. 1, 3, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.803, + 0.468, + 0.843 + ], + "angle": 0, + "content": "[13] Christoph Feichtenhofer, Haoqi Fan, Yanghao Li, and Kaiming He. Masked autoencoders as spatiotemporal learners. NeurIPS, 2022. 2, 4, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.845, + 0.468, + 0.9 + ], + "angle": 0, + "content": "[14] Basura Fernando, Efstratios Gavves, José Oramas, Amir Ghodrati, and Tinne Tuytelaars. Rank pooling for action recognition. IEEE transactions on pattern analysis and machine intelligence, 39(4):773-787, 2016. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.115, + 0.468, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[15] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In CVPR, 2022. 1, 2, 4, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.178 + ], + "angle": 0, + "content": "[16] Kaiming He, Haoqi Fan, Yuxin Wu, Saining Xie, and Ross Girshick. Momentum contrast for unsupervised visual representation learning. In CVPR, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.179, + 0.892, + 0.22 + ], + "angle": 0, + "content": "[17] Ji Hou, Benjamin Graham, Matthias Nießner, and Saining Xie. Exploring data-efficient 3D scene understanding with contrastive scene contexts. In CVPR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.223, + 0.892, + 0.264 + ], + "angle": 0, + "content": "[18] Siyuan Huang, Yichen Xie, Song-Chun Zhu, and Yixin Zhu. Spatio-temporal self-supervised representation learning for 3D point clouds. In ICCV, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.266, + 0.892, + 0.32 + ], + "angle": 0, + "content": "[19] Jacob Devlin Ming-Wei Chang Kenton and Lee Kristina Toutanova. BERT: Pre-training of deep bidirectional transformers for language understanding. In NAACL, 2019. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.323, + 0.892, + 0.364 + ], + "angle": 0, + "content": "[20] Wanqing Li, Zhengyou Zhang, and Zicheng Liu. Action recognition based on a bag of 3D points. In CVPRW, 2010. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.367, + 0.892, + 0.422 + ], + "angle": 0, + "content": "[21] Hanxue Liang, Hehe Fan, Zhiwen Fan, Yi Wang, Tianlong Chen, Yu Cheng, and Zhangyang Wang. Point cloud domain adaptation via masked local 3D structure prediction. In ECCV, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.424, + 0.892, + 0.465 + ], + "angle": 0, + "content": "[22] Haotian Liu, Mu Cai, and Yong Jae Lee. Masked discrimination for self-supervised learning on point clouds. In ECCV, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.468, + 0.892, + 0.509 + ], + "angle": 0, + "content": "[23] Xingyu Liu, Charles R Qi, and Leonidas J Guibas. Flownet3D: Learning scene flow in 3D point clouds. In CVPR, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.511, + 0.892, + 0.552 + ], + "angle": 0, + "content": "[24] Xingyu Liu, Mengyuan Yan, and Jeannette Bohg. MeteorNet: Deep learning on dynamic 3D point cloud sequences. In ICCV, 2019. 1, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.554, + 0.892, + 0.595 + ], + "angle": 0, + "content": "[25] Ze Liu, Jia Ning, Yue Cao, Yixuan Wei, Zheng Zhang, Stephen Lin, and Han Hu. Video swim transformer. In CVPR, 2022. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.598, + 0.892, + 0.64 + ], + "angle": 0, + "content": "[26] Yuecong Min, Xiujuan Chai, Lei Zhao, and Xilin Chen. FlickerNet: Adaptive 3D gesture recognition from sparse point clouds. In BMVC, 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.642, + 0.892, + 0.683 + ], + "angle": 0, + "content": "[27] Yuecong Min, Yanxiao Zhang, Xiujuan Chai, and Xin Chen. An efficient PointLSTM for point clouds based gesture recognition. In CVPR, 2020. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.686, + 0.892, + 0.74 + ], + "angle": 0, + "content": "[28] Pavlo Molchanov, Xiaodong Yang, Shalini Gupta, Kihwan Kim, Stephen Tyree, and Jan Kautz. Online detection and classification of dynamic hand gestures with recurrent 3D convolutional neural network. In CVPR, 2016. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.742, + 0.892, + 0.784 + ], + "angle": 0, + "content": "[29] Yatian Pang, Wenxiao Wang, Francis E.H. Tay, Wei Liu, Yonghong Tian, and Li Yuan. Masked autoencoders for point cloud self-supervised learning. In ECCV, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.786, + 0.892, + 0.814 + ], + "angle": 0, + "content": "[30] Helmut Pottmann and Johannes Wallner. Computational line geometry. Springer, 2001. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.816, + 0.892, + 0.857 + ], + "angle": 0, + "content": "[31] Rui Qian, Shuangrui Ding, Xian Liu, and Dahua Lin. Static and dynamic concepts for self-supervised video representation learning. In ECCV, 2022. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.859, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[32] Yongming Rao, Jiwen Lu, and Jie Zhou. Global-local bidirectional reasoning for unsupervised representation learning of 3D point clouds. In CVPR, 2020. 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.956 + ], + "angle": 0, + "content": "16588" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.134 + ], + "angle": 0, + "content": "[33] Amir Shahroudy, Jun Liu, Tian-Tsong Ng, and Gang Wang. NTU RGB+D: A large scale dataset for 3D human activity analysis. In CVPR, 2016. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.469, + 0.19 + ], + "angle": 0, + "content": "[34] Zhiqiang Shen, Xiaoxiao Sheng, Longguang Wang, Yulan Guo, Qiong Liu, and Xi Zhou. Pointemp: Contrastive mask prediction for self-supervised learning on point cloud videos. In CVPR, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.192, + 0.469, + 0.234 + ], + "angle": 0, + "content": "[35] Xiaoxiao Sheng, Zhiqiang Shen, and Gang Xiao. Contrastive predictive autoencoders for dynamic point cloud self-supervised learning. In AAAI, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.236, + 0.469, + 0.275 + ], + "angle": 0, + "content": "[36] Karen Simonyan and Andrew Zisserman. Two-stream convolutional networks for action recognition in videos. In NeurIPS, 2014. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.278, + 0.469, + 0.331 + ], + "angle": 0, + "content": "[37] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. VideoMAE: Masked autoencoders are data-efficient learners for self-supervised video pre-training. In NeurIPS, 2022. 2, 4, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.334, + 0.469, + 0.389 + ], + "angle": 0, + "content": "[38] Haiyan Wang, Liang Yang, Xuejian Rong, Jinglun Feng, and Yingli Tian. Self-supervised 4D spatio-temporal feature learning via order prediction of sequential point cloud clips. In WACV, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.391, + 0.469, + 0.445 + ], + "angle": 0, + "content": "[39] Rui Wang, Dongdong Chen, Zuxuan Wu, Yinpeng Chen, Xiyang Dai, Mengchen Liu, Yu-Gang Jiang, Luowei Zhou, and Lu Yuan. BEVT: BERT pretraining of video transformers. In CVPR, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.448, + 0.469, + 0.502 + ], + "angle": 0, + "content": "[40] Yancheng Wang, Yang Xiao, Fu Xiong, Wenxiang Jiang, Zhiguo Cao, Joey Tianyi Zhou, and Junsong Yuan. 3DV: 3D dynamic voxel for action recognition in depth video. In CVPR, 2020. 1, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.504, + 0.469, + 0.558 + ], + "angle": 0, + "content": "[41] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In CVPR, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.561, + 0.469, + 0.602 + ], + "angle": 0, + "content": "[42] Yimin Wei, Hao Liu, Tingting Xie, Qiuhong Ke, and Yulan Guo. Spatial-temporal transformer for 3D point cloud sequences. In WACV, 2022. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.604, + 0.469, + 0.645 + ], + "angle": 0, + "content": "[43] Hao Wen, Yunze Liu, Jingwei Huang, Bo Duan, and Li Yi. Point primitive transformer for long-term 4D point cloud video understanding. In ECCV, 2022. 1, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.647, + 0.469, + 0.699 + ], + "angle": 0, + "content": "[44] Saining Xie, Jiatao Gu, Demi Guo, Charles R Qi, Leonidas Guibas, and Or Litany. PointContrast: Unsupervised pretraining for 3D point cloud understanding. In ECCV, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.703, + 0.469, + 0.744 + ], + "angle": 0, + "content": "[45] Zhenda Xie, Zheng Zhang, Yue Cao, Yutong Lin, Jianmin Bao, Zhuliang Yao, Qi Dai, and Han Hu. SimMIM: A simple framework for masked image modeling. In CVPR, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.746, + 0.469, + 0.786 + ], + "angle": 0, + "content": "[46] Yaoqing Yang, Chen Feng, Yiru Shen, and Dong Tian. FoldingNet: Point cloud auto-encoder via deep grid deformation. In CVPR, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.789, + 0.469, + 0.842 + ], + "angle": 0, + "content": "[47] Xumin Yu, Lulu Tang, Yongming Rao, Tiejun Huang, Jie Zhou, and Jiwen Lu. Point-BERT: Pre-training 3D point cloud transformers with masked point modeling. In CVPR, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.469, + 0.899 + ], + "angle": 0, + "content": "[48] Zhuoyang Zhang, Yuhao Dong, Yunze Liu, and Li Yi. Complete-to-partial 4D distillation for self-supervised point cloud sequence representation learning. arXiv preprint arXiv:2212.05330, 2022. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.092, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[49] Zaiwei Zhang, Rohit Girdhar, Armand Joulin, and Ishan Misra. Self-supervised pretraining of 3D features on any point-cloud. In ICCV, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.204 + ], + "angle": 0, + "content": "[50] Jia-Xing Zhong, Kaichen Zhou, Qingyong Hu, Bing Wang, Niki Trigoni, and Andrew Markham. No Pain, Big Gain: Classify dynamic point cloud sequences with static models by fitting feature-level space-time surfaces. In CVPR, 2022. 1, 3, 5, 6" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.092, + 0.892, + 0.204 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.956 + ], + "angle": 0, + "content": "16589" + } + ] +] \ No newline at end of file diff --git a/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/e14b4021-babf-4da5-a112-3aa5b237ce50_origin.pdf b/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/e14b4021-babf-4da5-a112-3aa5b237ce50_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..837249922543dc49f6d8f456ea8b81059edf8710 --- /dev/null +++ b/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/e14b4021-babf-4da5-a112-3aa5b237ce50_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:7337482bd07a880b7b2d56620b65d96188041745de5fb11e705ad4990cf4573a +size 2565307 diff --git a/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/full.md b/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/full.md new file mode 100644 index 0000000000000000000000000000000000000000..44d569e182131ec5a851ae38e9da27e92feb1471 --- /dev/null +++ b/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/full.md @@ -0,0 +1,333 @@ +# Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos + +Zhiqiang Shen $^{1,5*}$ , Xiaoxiao Sheng $^{1*}$ , Hehe Fan $^{2\dagger}$ , Longguang Wang $^{3}$ , Yulan Guo $^{4}$ , Qiong Liu $^{5}$ , Hao Wen $^{5}$ , Xi Zhou $^{1,5}$ $^{1}$ Shanghai Jiao Tong University $^{2}$ Zhejiang University $^{3}$ Aviation University of Air Force $^{4}$ Sun Yat-sen University $^{5}$ CloudWalk + +# Abstract + +Recently, the community has made tremendous progress in developing effective methods for point cloud video understanding that learn from massive amounts of labeled data. However, annotating point cloud videos is usually notoriously expensive. Moreover, training via one or only a few traditional tasks (e.g., classification) may be insufficient to learn subtle details of the spatio-temporal structure existing in point cloud videos. In this paper, we propose a Masked Spatio-Temporal Structure Prediction (MaST-Pre) method to capture the structure of point cloud videos without human annotations. MaST-Pre is based on spatio-temporal point-tube masking and consists of two self-supervised learning tasks. First, by reconstructing masked point tubes, our method is able to capture the appearance information of point cloud videos. Second, to learn motion, we propose a temporal cardinality difference prediction task that estimates the change in the number of points within a point tube. In this way, MaST-Pre is forced to model the spatial and temporal structure in point cloud videos. Extensive experiments on MSRAction-3D, NTU-RGBD, NvGesture, and SHREC'17 demonstrate the effectiveness of the proposed method. The code is available at https://github.com/JohnsonSign/MaST-Pre. + +# 1. Introduction + +In physics, motion is the phenomenon in which position changes over time. Because point clouds provide precise position information, i.e., 3D coordinates, point cloud videos, which evolve over time, can accurately describe the 3D motion in the real world. Effectively understanding point cloud videos can significantly improve intelligent agents on the interaction with environments. Therefore, the community has developed a few effective methods for + +![](images/b40a14514a2720f9027a0ed9d71f7e3584cc5f0ec63cfe8e21642e0a7eb9394c.jpg) +Figure 1. Our MaST-Pre is based on spatio-temporal point-tube masking. To enable a model to capture the appearance structure in point cloud videos, we ask it to reconstruct masked point tubes. To equip the model with motion modeling ability, we develop a temporal cardinality difference prediction task. + +point cloud video understanding, including video classification [9-12, 40, 50] and semantic segmentation [6, 24, 42, 43]. However, most of these methods are based on supervised learning and that requires much effort to carefully annotate massive amounts of labels. Moreover, learning via only classification or segmentation may make deep neural networks take too much emphasis on the task itself but largely ignore the subtle details of the instinct spatiotemporal structure in point cloud videos. To alleviate those problems, we propose a self-supervised learning method on point cloud videos. + +Self-supervised learning uses supervisory signals from the data itself and enables deep neural networks to learn from massive data without human annotations. This is important to recognize more subtle patterns in data. Networks pre-trained with self-supervised learning usually yield higher performance than when solely trained in a supervised manner [5, 15, 16, 19]. Although self-supervised + +learning has been applied to images [15], videos [13, 37] and static point clouds [29, 47], it has not been promoted on 4D signals, such as point cloud videos. Visual signals in point cloud videos can be divided into appearance and motion. While appearance specifies which objects are in videos, motion describes their dynamics. Therefore, self-supervised learning on point cloud videos should carefully make the most of the appearance and motion structure. + +In this paper, we propose a Masked Spatio-Temporal Structure Prediction (MaST-Pre) method for self-supervised learning on point cloud videos (Fig. 1). MaST-Pre is based on a masking strategy, which has been proven effective in a range of applications. For example, because of the canonical structure, images can be easily segmented into multiple patches for masking [8, 15], which in the case of video are extended to patch tubes [13, 37]. For unstructured static point clouds, spherical support domain masking can be used for masked autoencoder [29, 47]. However, the spatial irregularity and temporal regularity make point cloud videos require a more elaborate masking strategy. Our method is based on a masked point tube mechanism, where a point tube is a local area expanding over a short time [11]. + +Based on point-tube masking, our MaST-Pre employs two self-supervised tasks to capture the appearance and motion structure, respectively. First, to learn the appearance structure, MaST-Pre is asked to predict the invisible parts of the input from unmasked points. Second, to capture the dynamics in point tubes, we propose the temporal cardinality difference, which can be calculated online from inputs without additional parameters. Cardinality can reflect basic structures (e.g., line, edge, and plane) of static point clouds [21]. In this paper, we extend it to a temporal version so that it can model the dynamics of point cloud videos. Intuitively, the temporal cardinality difference characterizes the flow of points within a short time. Therefore, inferring the temporal cardinality difference of masked point tubes facilitates MaST-Pre to learn motion-informative representations. Our contributions are summarized as follows: + +- We design a 4D scheme of masked prediction for self-supervised learning on point cloud videos, termed as MaST-Pre. Our MaST-Pre jointly learns the appearance and motion structure of point cloud videos. +- We propose the temporal cardinality difference, a simple and effective motion feature directly captured from raw input points. It explicitly guides MaST-Pre to learn motion-informative representations. +- Extensive experiments and ablation studies on several benchmark datasets validate that our MaST-Pre learns rich representations of point cloud videos. + +# 2. Related Work + +In this section, we first briefly review visual mask prediction for self-supervised learning. Then, we present recent advances in self-supervised learning on point clouds and dynamics modeling for point cloud videos. + +# 2.1. Visual Mask Prediction + +Mask prediction has been proven to be an excellent self-supervised task for visual representation learning [8,15,45]. By reconstructing target signals from the masked input, mask prediction enables the network to learn rich representations and boosts self-supervised learning [2,4,39,41]. Chen et al. [4] extended GPT [3] to operate the pixel sequence for prediction. Bao et al. [2] and Wang et al. [39] introduced another successful framework, BERT [19], to predict the identities of masked tokens. + +Then, He et al. [15] proposed MAE as a scalable vision learner to predict the pixels of masked patches. Feichtenhofer et al. [13] and Tong et al. [37] extended MAE to video representation learning by masking patch tubes. Wei et al. [41] developed MaskFeat to predict the HOG features of masked spatio-temporal tubes for self-supervised video pretraining. The regular structure of images and videos makes it easy to obtain patches or patch tubes, which facilitates the design of masking strategies. Pang et al. [29] extended MAE to unstructured static point clouds and designed a masking strategy based on the local spatial neighborhoods. However, point cloud videos are not only spatially irregular but also temporally misaligned across frames [9, 11]. To remedy this, we design a point-tube masking strategy. + +# 2.2. Self-supervised Learning on Point Clouds + +Contrastive learning has made significant progress on static point clouds [17, 32, 44, 49]. Xie et al. [44] proposed PointContrast to discriminate two geometric views of matched points using contrastive loss. Hou et al. [17] introduced contextual contrastive learning to PointContrast for data-efficient point pre-training. Rao et al. [32] mapped the local and global features to shared representation space and applied a contrastive loss on them. Zhang et al. [49] used the instance discrimination task on two augmented versions of a point cloud, while Huang et al. [18] pre-trained static point clouds using spatio-temporal augmentations. They transformed different views at point, region, object, and scene levels, and then used contrastive learning to judge their semantic consistency. However, there are limited augmentation methods that can guarantee the semantic consistency of point clouds, let alone point cloud videos. + +Prediction-based methods on point clouds also attract a lot of attention. Yang et al. [46] proposed a folding-based autoencoder that deforms a 2D grid to reconstruct the target 3D point cloud. Recently, mask prediction has been extended to static point clouds. Liu et al. [22] designed a point + +![](images/dad6bc8cee570461f85a6ff64696d5f6822c600719193bde0ee7de9205b7b572.jpg) +Figure 2. Illustration of the proposed MaST-Pre method. First, given a point cloud video, MaST-Pre divides it into several point tubes and masks part of them. Then, based on an encoder-decoder architecture, MaST-Pre attempts to recover masked point tubes and predict their temporal cardinality difference. + +discrimination task for masked patches. Yu et al. [47] proposed PointBERT with an offline point tokenizer. Pang et al. [29] used a simpler task, reconstructing masked point coordinates, for point pre-training in an end-to-end manner. However, these methods solely focus on the geometric representation learning of static point clouds. In this paper, on top of learning appearance information, an explicit motion information learning method is designed for point cloud videos. + +# 2.3. Dynamics Modeling for Point Cloud Videos + +Supervised learning dominates point cloud video research. [11, 12] and [9, 10, 42, 43] use convolution-based methods and attention-based methods to implicitly learn the long-term features of point cloud videos, respectively. In addition, [24, 40, 50] apply empirical-based dynamics methods modeling point cloud videos. Wang et al. [40] introduced temporal rank pooling [14] to capture the frame-level dynamics. Zhong et al. [50] proposed a two-stream framework and used feature-level ST-surfaces [30] in the dynamics learning branch. Liu et al. [24] used a scene flow estimator [23] or an alternative grouping method to do point tracking for dynamics modeling. Although these methods are effective, they require complex calculations or additional modules. + +Self-supervised learning on point cloud videos is understudied [34, 35]. Wang et al. [38] pre-trained the encoder by predicting the temporal order of shuffled segments to learn the dynamics of point cloud videos. Zhang et al. [48] developed complete-to-partial 4D distillation to predict the representations of point cloud frames within a short time window. However, these methods learn motion information using clip-level or frame-level pretext tasks. In this paper, we propose the temporal cardinality difference prediction + +for fine-grained dynamics learning on point cloud videos. + +# 3. Method + +The architecture of our MaST-Pre is illustrated in Fig. 2. Given a point cloud video, it is first divided into multiple point tubes. Next, a masking operation is performed, separating these point tubes into visible and invisible parts. The visible ones are fed to an encoder, and then their updated embeddings are fed to the decoder along with the masked point tubes. Afterward, two-stream prediction tasks are implemented to recover the point coordinates within masked point tubes and to infer their temporal cardinality differences, respectively. Intuitively, enabling the decoder to perform well on two-stream prediction tasks demands the encoder to learn representations rich in appearance and motion information jointly. + +# 3.1. Masking Strategy + +The masking strategy includes three steps: input division, embedding, and masking operation. + +Division. Point tubes are introduced as division units of the input point cloud video. Specifically, given a point cloud video $\pmb{P}$ , Farthest Point Sampling is used to select $N$ key points $\hat{\pmb{p}}$ from the input. Next, we construct one point tube for each key point. The point tube centered at $i$ -th key point $\hat{p}_i$ is denoted as $\pmb{T}\pmb{u}\pmb{e}_{\hat{p}_i} = \{p \mid p \in \pmb{P}, \mathcal{D}_s(p, \hat{p}_i) < r, \mathcal{D}_t(p, \hat{p}_i) < \frac{l}{2}\}$ , where $p$ is one of the input points, $\mathcal{D}_s$ is the Euclidean distance, $\mathcal{D}_t$ is the difference in frame timestamps of two points, $r$ is the radius of a spatial neighborhood and $l$ is the number of frames in a point tube. Then, we use random sampling to select $n$ points in each spatial neighborhood. + +In this way, a point cloud video is divided into $N$ point tubes, and each point tube contains $l \times n$ points. To en + +(a) Cardinality Histogram +Figure 3. Illustration of Cardinality Histogram (a) and Temporal Cardinality Difference (b). +![](images/8defb88c45c42b96b704055e14bff5a18eb9ff14f4944abf73fc46700d127cc9.jpg) +I $\sim$ VIII Octant +-·-· +Oct +ant Central Line +# +Points + +(b) Temporal Cardinality Difference +![](images/20ca32a24269e34bf21bac915d8dea42c334d81c44700f53ad35efbede127f12.jpg) +$d_{1}d_{2}d_{3}d_{4}$ +Angular Distance to Octant Central Line + +sure all points are covered by point tubes, $r$ and $l$ are set to maintain a minor overlap between adjacent point tubes. + +**Embedding.** Following our baseline [9], each point tube is encoded into an embedding: + +$$ +\boldsymbol {E} _ {\hat {p} _ {i}} = \sum_ {t = 1} ^ {l} \sum_ {p \in \boldsymbol {T u b e} _ {\hat {p} _ {i}} ^ {t}} f (p - \hat {p} _ {i}), \tag {1} +$$ + +where $\mathbf{Tube}_{\hat{p}_i}^t$ is the $t$ -th frame of the point tube centered at $\hat{p}_i$ and $f(\cdot)$ is an MLP-based feature extractor. More details can be found in [9]. + +Masking. The design of the masking operation is related to the information redundancy of input [13, 15, 37]. Because of spatio-temporal coherence, the redundancy of the point cloud video is higher than low-dimensional data. Therefore, our MaST-Pre uses a high masking ratio on point cloud videos and the empirical result is $75\%$ . A high ratio is helpful to alleviate information leakage and make reconstruction a meaningful self-supervised task. In addition, our MaST-Pre uses random masking of point tubes. As a spacetime-agnostic method, random masking is more effective than structure-aware strategies [13]. + +# 3.2. Autoencoding + +Our autoencoder is based on vanilla Transformers of point cloud videos [9]. An asymmetric encoder-decoder design is introduced to MaST-Pre. + +Encoder. To better capture the dynamics of point cloud videos, joint spatio-temporal attention is adopted [1,25]. In addition, only the visible point tubes with spatio-temporal positional embeddings are fed into the encoder during pretraining. + +Decoder. The decoder is similar to our encoder but a lightweight vanilla Transformer [9]. It takes both encoded point tubes and masked ones as input. By adding a full set of spatio-temporal positional embeddings to all tokens, location clues are provided for self-supervised learning. After decoding, only the embeddings of masked point tubes are fed to the following prediction heads. + +# 3.3. Two-stream Prediction + +It is demonstrated in [31, 36] that effective video representation integrates appearance and motion information. Therefore, two-stream self-supervised tasks are proposed to explicitly predict motions and reconstruct the appearance of masked point cloud videos. + +Appearance Stream. The reconstruction objectives are the point coordinates of masked point tubes. The $l_{2}$ Chamber Distance loss is used between predictions $P_{pre} \in \mathbb{R}^{l \times n \times 3}$ and the ground truth $P_{gt} \in \mathbb{R}^{l \times n \times 3}$ : + +$$ +\begin{array}{l} \mathcal {L} _ {a p p} = \frac {1}{l} \sum_ {i = 1} ^ {l} \left\{\frac {1}{| \boldsymbol {P} _ {p r e} ^ {i} |} \sum_ {a \in \boldsymbol {P} _ {p r e} ^ {i}} \min _ {b \in \boldsymbol {P} _ {g t} ^ {i}} \| a - b \| _ {2} ^ {2} + \right. \tag {2} \\ \left. \frac {1}{| \boldsymbol {P} _ {g t} ^ {i} |} \sum_ {b \in \boldsymbol {P} _ {g t} ^ {i}} \min _ {a \in \boldsymbol {P} _ {p r e} ^ {i}} \| b - a \| _ {2} ^ {2} \right\}. \\ \end{array} +$$ + +Motion Stream. We propose the temporal cardinality difference as the target of the motion prediction stream. As shown in Fig. 3(a), the spherical support domain of the key point is divided into 8 octants. We follow the conventional rule that the area where the $xyz$ -coordinates are greater than 0 is the first octant I and then increases counterclockwise. + +Then, count the cardinality of each octant into the corresponding bin of a histogram. To alleviate the noise in real-world point clouds, a probabilistic approach is employed. Specifically, calculate the angular distance $d$ of each point to the central line of its current octant, and divide it by $90^{\circ}$ to normalize. For example, the current octant of Point2 (the green one in Fig. 3(a)) is octant III. The angular difference $d2$ between Point2 and the central dashed line of octant III is $30^{\circ}$ . Consequently, the probabilities of Point2 belonging to octant IV and III are $\frac{1}{3}$ (i.e., $\frac{30^{\circ}}{90^{\circ}}$ ) and $\frac{2}{3}$ (i.e., $\frac{60^{\circ}}{90^{\circ}}$ ), respectively. In particular, when a point falls on an axis (e.g., the $-y$ axis), its probabilities belonging to octant IV and III are both 0.5. + +Next, as shown in Fig. 3(b), the cardinality histograms $C \in \mathbb{R}^8$ between adjacent frames of a point tube are subtracted to obtain its temporal cardinality difference $CD \in \mathbb{R}^8$ , which constitutes the ground truth $M_{gt} \in \mathbb{R}^{(l-1) \times 8}$ of the motion stream. The decoded embeddings of masked point tubes are passed through a linear layer to obtain the motion prediction $M_{pre} \in \mathbb{R}^{(l-1) \times 8}$ . The smooth $l_1$ loss of $i$ -th $CD$ between prediction and ground truth is denoted as $\mathcal{L}_m^i$ . The loss of our motion stream is denoted as $\mathcal{L}_{motion}$ : + +$$ +\mathcal {L} _ {m} ^ {i} = \left\{ \begin{array}{l l} 0. 5 \times \left(M _ {p r e} ^ {i} - M _ {g t} ^ {i}\right) ^ {2}, & \text {i f} \left| M _ {p r e} ^ {i} - M _ {g t} ^ {i} \right| < 1 \\ \left| M _ {p r e} ^ {i} - M _ {g t} ^ {i} \right| - 0. 5, & \text {o t h e r w i s e} \end{array} , \right. \tag {3} +$$ + +$$ +\mathcal {L} _ {\text {m o t i o n}} = \frac {1}{l - 1} \sum_ {i = 1} ^ {l - 1} \mathcal {L} _ {m} ^ {i}. \tag {4} +$$ + +Overall, the total loss of our MaST-Pre is defined as: + +$$ +\mathcal {L} _ {\text {t o t a l}} = \mathcal {L} _ {\text {a p p}} + \mathcal {L} _ {\text {m o t i o n}}. \tag {5} +$$ + +With both loss terms, our MaST-Pre can simultaneously learn the geometry and dynamics of point cloud videos. + +# 4. Experiments + +Our experiments are conducted on four point cloud video datasets. Following [13, 15, 37], we implement end-to-end fine-tuning, semi-supervised learning, and transfer learning to evaluate the pre-trained MaST-Pre. Afterward, ablation studies are conducted to analyze the design of our MaST-Pre and show the visualization results. + +# 4.1. Datasets + +In this paper, to demonstrate the effectiveness of our spatio-temporal representations, we focus on long-term point cloud video tasks, including 4D action recognition and 4D gesture recognition. + +MSRAction-3D [20] and NTU-RGBD [33] are utilized for the action recognition task. (1) MSRAction-3D is comprised of 567 videos in 20 daily actions. The average + +Table 1. Action recognition accuracy on MSRAction-3D. + +
MethodsAccuracy (%)
Supervised LearningMeteorNet [24]88.50
PSTNet [11]91.20
PSTNet++ [12]92.68
Kinet [50]93.27
PPTr [43]92.33
P4Transformer [9]90.94
PST-Transformer [10]93.73
End-to-end Fine-tuningP4Transformer + MaST-Pre91.29
PST-Transformer + MaST-Pre94.08
+ +frame number contained in each video is about 40. Following [9, 10], 270 videos are used as the training set and 297 videos are adopted as the test data. (2) NTU-RGBD consists of 56,880 videos with 60 fine-grained action categories. The frame number of each video is about 30 to 300. Under the cross-subject setting [33], 40,320 training videos and 16,560 test videos are used. + +SHREC'17 [7] and NvGesture [28] are utilized for the gesture recognition task. (1) SHREC'17 is comprised of 2800 videos in 28 gestures. Following [7], this dataset is split into 1960 training videos and 840 test videos. (2) NvGesture consists of 1532 videos with 25 gesture classes. Following [27], 1050 videos are assigned to the training set and the remaining 482 videos to the test set. + +# 4.2. Pre-training + +During pre-training, given a point cloud video, 24 frames are densely sampled and 1024 points are selected for each frame. Following [9, 10], the frame sampling stride is set to 2/1 on NTU-RGBD/MSRAction-3D and only random scaling is employed for data augmentation. For division and embedding, the temporal downsampling rate is set to 2 and the temporal kernel size $l$ of each point tube is set to 3. Meanwhile, the spatial downsampling rate is set to 32. The radius of each support domain $r$ is set to 0.1/0.3 on NTU-RGBD/MSRAction-3D and the number of neighbor points $n$ within the spherical query is set to 32. The masking ratio is set to $75\%$ unless otherwise specified. + +P4Transformer [9] is utilized as our encoder, which consists of 10/5 layers of vanilla Transformers on NTU-RGBD/MSRAction-3D. The decoder is a 4-layer transformer. To verify the extensibility, PST-Transformer [10] is also used as an encoder on MSRAction-3D. Our MaST-Pre is pre-trained for 200 epochs and linear warmup is utilized for the first 10 epochs. The AdamW optimizer is used with a batch size of 128, and the initial learning rate is set to 0.001 with a cosine decay strategy. + +Table 2. Action recognition accuracy (%) on NTU-RGBD under cross-subject setting. + +
MethodsAcc.
3DV-Motion [40]84.5
3DV-PointNet++ [40]88.8
PSTNet [11]90.5
PSTNet++ [12]91.4
Kinet [50]92.3
P4Transformer [9]90.2
PST-Transformer [10]91.0
P4Transformer + MaST-Pre (End-to-end Fine-tuning)90.8
P4Transformer + MaST-Pre (50% Semi-supervised)87.8
+ +# 4.3. End-to-end Fine-tuning + +We first evaluate our MaST-Pre by fine-tuning the pretrained encoder with a new classifier in a supervised manner. End-to-end fine-tuning experiments are conducted on NTU-RGBD and MSRAction-3D, respectively. In each experiment, the same dataset is used for pre-training and fine-tuning. + +MSRAction-3D. During fine-tuning, 24 frames are densely sampled and 2048 points are selected in each frame. Following [11], the spatial search radius is set to 0.7. The model is trained for 50 epochs with a batch size of 12 on 4 GPUs. We use the AdamW optimizer and the initial learning rate is set to 0.001 with a cosine decay strategy. As shown in Table 1, compared with baselines trained in a fully supervised manner, our MaST-Pre introduces accuracy improvements for both P4Transformer and PST-Transformer. According to prior experience, the masked autoencoder needs to be fed a considerable amount of data in the pretraining stage to learn useful knowledge [13, 15]. However, the MSRAction-3D dataset is too small to bring significant improvement. + +NTU-RGBD. The setup of fine-tuning is the same as pre-training, except that the pre-trained model is fine-tuned for 20 epochs with a batch size of 48 on 8 GPUs and the initial learning rate is set to 0.0005. From the end-to-end fine-tuning in Table 2, we can see that our pre-training method introduces an accuracy improvement compared with the baseline. By predicting the spatio-temporal structure, our MaST-Pre learns appearance and motion information during pre-training. + +# 4.4. Semi-supervised Learning + +We also evaluate the learned representations using a semi-supervised learning experiment. Specifically, the cross-subject training set of NTU-RGBD is used for pretraining, and then only a $50\%$ training set is used for finetuning in a supervised manner. The setup of our semi-supervised learning experiment is the same as end-to-end fine-tuning on NTU-RGBD (Sec. 4.3). + +Table 3. Gesture recognition accuracy (\%) on NvGesture (NvG) and SHREC'17 (SHR). + +
MethodsNvGSHR
FlickerNet [26]86.3-
PLSTM [27]85.987.6
PLSTM-PSS [27]87.393.1
Kinet [50]89.195.2
P4Transformer [9] (30 Epochs)84.887.5
P4Transformer [9] (50 Epochs)87.791.2
P4Transformer + MaST-Pre (30 Epochs)87.690.2
P4Transformer + MaST-Pre (50 Epochs)89.392.4
+ +From Table 2, we can see that the $50\%$ semi-supervised result produced by our MaST-Pre achieves comparable performance to the fully supervised baseline even with only limited annotated data. This clearly demonstrates that MaST-Pre learns high-quality representations. + +# 4.5. Transfer Learning + +To evaluate the generalization ability of the representations learned by MaST-Pre, we conduct experiments by transferring the pre-trained encoder to other datasets. Specifically, the encoder is first pre-trained on NTU-RGBD following the setup in Sec. 4.2, and then fine-tuned with a new classifier on NvGesture and SHREC'17, respectively. Our transfer experiments are not only cross-dataset but also cross-task, i.e., from action recognition to gesture recognition. We compare our fine-tuned results to the fully supervised baseline in Table 3. + +During fine-tuning, an AdamW optimizer with a batch size of 24 is used, and the initial learning rate is set to 0.002 with a cosine decay strategy. The pre-trained model is fine-tuned for 50 epochs on NvGesture and SHREC'17. As shown in Table 3, our MaST-Pre pre-training facilitates the P4Transformer to produce superior accuracy compared to the fully supervised baseline. Moreover, our MaST-Pre also performs faster convergence. Compared with the baseline without pre-training, significant improvements are achieved after fine-tuning for only 30 epochs (e.g., $84.8\% \rightarrow 87.6\%$ on NvGesture and $87.5\% \rightarrow 90.2\%$ on SHREC'17). This demonstrates that our MaST-Pre has excellent generalization ability across different tasks, facilitating the accuracy improvement of downstream tasks. + +# 4.6. Ablation Studies + +In order to balance authority and efficiency, the experiments of ablation studies are conducted on $10\%$ NTU-RGBD, which contains 4032 training videos and 1656 test videos with category balance. + +Architecture Design. Our MaST-Pre utilizes a two-stream prediction to jointly learn both appearance and motion information. To demonstrate the effectiveness of this + +![](images/9528bb91f590fd312dfdf100d83b75bff3863b40d801f734f3c09766605af0c0.jpg) +Figure 4. Visualization of reconstruction results. For each action sample, the ground truth lies in the first row, the masked video lies in the second row, and the result lies in the third row. + +![](images/1148d5257b196bd26e29b7ac0286ca37566e3d11fd510131040ecc8b0dc302c2.jpg) +Rnne aenrnnnne nnnnne ennnnne eannnne + +Table 4. Ablation studies on pre-training architectures. + +
Appearance StreamMotion StreamAcc. (%)
A065.85
A1✓70.13
A2 (Ours)✓✓78.25
+ +Table 5. Ablation studies on masking ratios. + +
B1B2 (Ours)B3
Masking Ratio65%75%85%
Accuracy (%)76.9178.2577.20
+ +architecture, we first present the performance of model A0 as the $10\%$ NTU-RGBD baseline in a fully supervised manner $(65.85\%)$ . Then, model A1 is developed by removing the motion prediction stream. Quantitative results are presented in Table 4. It shows that with solely the appearance stream, the performance gain introduced by model A1 pretraining is limited. When these two streams are combined, comprehensive information can be learned and superior accuracy is achieved by our model A2 $(65.85\% \rightarrow 78.25\%)$ . This demonstrates the effectiveness of our mask-based pretraining on point cloud videos and the necessity of the task of explicitly predicting motions. + +Masking Ratio. The masking operation plays a critical role in our MaST-Pre. Therefore, we conduct experiments + +Table 6. Ablation studies on the appearance stream. + +
# FramesTemporal & SpatialAccuracy (%)
D11-77.34
D23Coupling58.60
D3 (Ours)3Decoupling78.25
+ +to study different masking ratios, and the results are presented in Table 5. It shows that a high masking ratio is beneficial to our MaST-Pre and the highest accuracy is achieved at $75\%$ masking ratio (model B2). + +Appearance Stream. Right reconstruction targets in the appearance stream contribute to the performance of our MaST-Pre. For model D3, in each point tube, the reconstruction loss (Eq. 2) is first calculated in each frame separately and then aggregated over $l$ frames, which is a decoupled manner. In contrast, model D2 calculates the reconstruction loss in a coupled manner by considering all points together. We also develop model D1 to reconstruct only the middle frame of each point tube. + +As shown in Table 6, model D2 brings no accuracy gain and is even worse than the baseline model A0 (58.60% vs. 65.85%). In addition, D3 outperforms D1 and D2. This is because D3 implicitly learns spatio-temporal information during the process of reconstructing decoupled point tubes. We further visualize the reconstruction results in Fig. 4. + +![](images/1dc66e7b855c05ca16fddd4bb1ec50c13c11297491aa996f499b40007da396a3.jpg) + +![](images/e7150fb7486695d9870fe7efc64d989efa51cfde878394dbc3a2a08efb0a10c0.jpg) +Figure 5. Samples of temporal cardinality difference, computed by subtracting cardinality histograms of frame $t - 1$ from frame $t$ . + +Frame t-1 + +![](images/8c5d604dc5668e452de5a32e3f60b58970772c66f04550cd887059df5e0ddf5d.jpg) + +Frame $t$ + +![](images/62d965fd48f312bb9a034fc9fdce71491efc0c1bd33ba73bbbaebf1fb1305fd6.jpg) + +Movement + +![](images/b22d679be37653c6d254f32dcef9740ae31264fc409eecf7f701923503850eea.jpg) +(b) Putting Hands Down + +Key Point + +Support Domain + +![](images/057e03f0ae59c4725d190ae9cd8f4dc530050dcae4605c7be33a3574e2ee23a2.jpg) +(c) Kicking Forward + +![](images/28a411feced4c81fa9bb4bf3148c3ccf3b7bbdafd39aba34a2114c4b8853afae.jpg) + +Table 7. Ablation studies on the temporal cardinality difference. + +
E1E2 (Ours)E3
# Section4816
Accuracy (%)77.8578.2569.50
+ +
F1F2 (Ours)
InterpolationX✓
Accuracy (%)76.6978.25
+ +
G1 (Ours)G2
# Stride12
Accuracy (%)78.2575.85
+ +Temporal Cardinality Difference. In order to investigate the temporal cardinality difference, we present the results under different sections, interpolations, and strides in Table 7. We develop the model E1/E3 to divide the support domain into 4/16 sections, while their accuracy is lower than E2 with 8 sections. This is because small space resolution will introduce noises and large resolution makes temporal cardinality difference insensitive to motions. + +Next, we develop model F1 by removing interpolation. While F2 outperforms F1 because interpolation improves its robustness. Finally, we develop model G2 to calculate the cardinality difference with temporal stride 2, but its performance is worse than G1 with stride 1. This is because a large temporal stride cannot capture fine-grained motions. + +We further visualize multiple samples of temporal cardinality difference in Fig. 5 to demonstrate its effectiveness in modeling motions. We present three typical actions, each consisting of two samples. As shown in Fig. 5(a), the temporal cardinality differences of the two raising hands actions project extremely similar motion patterns. Points in the first and seventh octants flow out heavily over time. Meanwhile, temporal cardinality differences within putting hands down (Fig. 5(b)) also display similarities, as well as in kicking forward (Fig. 5(c)). In particular, the temporal cardinality differences between raising hands and putting hands down are approximately reversible, which reflects its effectiveness in modeling dynamics. + +Computational Complexity. Table 8 shows the pretraining complexity and corresponding fine-tuning accuracy of the two models. After adding the motion prediction stream, model H2 achieves much higher accuracy than + +Table 8. Time (mins/epoch) and memory (MiB) complexities. + +
ArchitecturesEncoderTimeMemoryAcc. (%)
H1Only Appearancew/o [M]5.4641470.13
H2 (Ours)Two Streamsw/o [M]6.2641878.25
+ +H1 with only a minor increase in pre-training complexities $(70.13\% \rightarrow 78.25\%)$ . + +# 5. Conclusion + +In this paper, we introduce a masked spatio-temporal structure prediction method for point cloud video pretraining, termed as MaST-Pre. For modeling subtle dynamics, the temporal cardinality difference is proposed, which can be calculated online directly from inputs. Based on point-tube masking, MaST-Pre jointly conducts point cloud video reconstruction and temporal cardinality difference prediction to learn both appearance and motion information. Experiments on four benchmarks show that our MaST-Pre is an effective pre-training framework to boost the performance of point cloud video understanding. + +Acknowledgments. This work was partially supported by the Fundamental Research Funds for the Central Universities (No. 226-2023-00048), the National Natural Science Foundation of China (No. U20A20185, 61972435), the Guangdong Basic and Applied Basic Research Foundation (2022B1515020103), the Shenzhen Science and Technology Program (No. RCYX20200714114641140), and the Chongqing Technology Innovation and Application Development Special Key Project(cstc2021jscx-cylhX0006). + +# References + +[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lučić, and Cordelia Schmid. Vivit: A video vision transformer. In ICCV, 2021. 4 +[2] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. BEiT: BERT pre-training of image transformers. In ICLR, 2022. 2 +[3] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, Sandhini Agarwal, Ariel Herbert-Voss, Gretchen Krueger, Tom Henighan, Rewon Child, Aditya Ramesh, Daniel Ziegler, Jeffrey Wu, Clemens Winter, Chris Hesse, Mark Chen, Eric Sigler, Mateusz Litwin, Scott Gray, Benjamin Chess, Jack Clark, Christopher Berner, Sam McCandlish, Alec Radford, Ilya Sutskever, and Dario Amodei. Language models are few-shot learners. In NeurIPS, 2020. 2 +[4] Mark Chen, Alec Radford, Rewon Child, Jeffrey Wu, Heewoo Jun, David Luan, and Ilya Sutskever. Generative pretraining from pixels. In ICML, 2020. 2 +[5] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning of visual representations. In ICML, 2020. 1 +[6] Christopher Choy, JunYoung Gwak, and Silvio Savarese. 4D spatio-temporal convnets: Minkowski convolutional neural networks. In CVPR, 2019. 1 +[7] Quentin De Smedt, Hazem Wannous, Jean-Philippe Vandeborre, Joris Guerry, Bertrand Le Saux, and David Filiat. SHREC'17 Track: 3D hand gesture recognition using a depth and skeletal dataset. In 3DOR, 2017. 5 +[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In ICLR, 2021. 2 +[9] Hehe Fan, Yi Yang, and Mohan Kankanhalli. Point 4D transformer networks for spatio-temporal modeling in point cloud videos. In CVPR, 2021. 1, 2, 3, 4, 5, 6 +[10] Hehe Fan, Yi Yang, and Mohan Kankanhalli. Point spatiotemporal transformer networks for point cloud video modeling. IEEE Transactions on Pattern Analysis and Machine Intelligence, 45(2):2181-2192, 2022. 1, 3, 5, 6 +[11] Hehe Fan, Xin Yu, Yuhang Ding, Yi Yang, and Mohan Kankanhalli. PSTNet: Point spatio-temporal convolution on point cloud sequences. In ICLR, 2021. 1, 2, 3, 5, 6 +[12] Hehe Fan, Xin Yu, Yi Yang, and Mohan Kankanhalli. Deep hierarchical representation of point cloud videos via spatio-temporal decomposition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(12):9918-9930, 2021. 1, 3, 5, 6 +[13] Christoph Feichtenhofer, Haoqi Fan, Yanghao Li, and Kaiming He. Masked autoencoders as spatiotemporal learners. NeurIPS, 2022. 2, 4, 5, 6 +[14] Basura Fernando, Efstratios Gavves, José Oramas, Amir Ghodrati, and Tinne Tuytelaars. Rank pooling for action recognition. IEEE transactions on pattern analysis and machine intelligence, 39(4):773-787, 2016. 3 + +[15] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In CVPR, 2022. 1, 2, 4, 5, 6 +[16] Kaiming He, Haoqi Fan, Yuxin Wu, Saining Xie, and Ross Girshick. Momentum contrast for unsupervised visual representation learning. In CVPR, 2020. 1 +[17] Ji Hou, Benjamin Graham, Matthias Nießner, and Saining Xie. Exploring data-efficient 3D scene understanding with contrastive scene contexts. In CVPR, 2021. 2 +[18] Siyuan Huang, Yichen Xie, Song-Chun Zhu, and Yixin Zhu. Spatio-temporal self-supervised representation learning for 3D point clouds. In ICCV, 2021. 2 +[19] Jacob Devlin Ming-Wei Chang Kenton and Lee Kristina Toutanova. BERT: Pre-training of deep bidirectional transformers for language understanding. In NAACL, 2019. 1, 2 +[20] Wanqing Li, Zhengyou Zhang, and Zicheng Liu. Action recognition based on a bag of 3D points. In CVPRW, 2010. 5 +[21] Hanxue Liang, Hehe Fan, Zhiwen Fan, Yi Wang, Tianlong Chen, Yu Cheng, and Zhangyang Wang. Point cloud domain adaptation via masked local 3D structure prediction. In ECCV, 2022. 2 +[22] Haotian Liu, Mu Cai, and Yong Jae Lee. Masked discrimination for self-supervised learning on point clouds. In ECCV, 2022. 2 +[23] Xingyu Liu, Charles R Qi, and Leonidas J Guibas. Flownet3D: Learning scene flow in 3D point clouds. In CVPR, 2019. 3 +[24] Xingyu Liu, Mengyuan Yan, and Jeannette Bohg. MeteorNet: Deep learning on dynamic 3D point cloud sequences. In ICCV, 2019. 1, 3, 5 +[25] Ze Liu, Jia Ning, Yue Cao, Yixuan Wei, Zheng Zhang, Stephen Lin, and Han Hu. Video swim transformer. In CVPR, 2022. 4 +[26] Yuecong Min, Xiujuan Chai, Lei Zhao, and Xilin Chen. FlickerNet: Adaptive 3D gesture recognition from sparse point clouds. In BMVC, 2019. 6 +[27] Yuecong Min, Yanxiao Zhang, Xiujuan Chai, and Xin Chen. An efficient PointLSTM for point clouds based gesture recognition. In CVPR, 2020. 5, 6 +[28] Pavlo Molchanov, Xiaodong Yang, Shalini Gupta, Kihwan Kim, Stephen Tyree, and Jan Kautz. Online detection and classification of dynamic hand gestures with recurrent 3D convolutional neural network. In CVPR, 2016. 5 +[29] Yatian Pang, Wenxiao Wang, Francis E.H. Tay, Wei Liu, Yonghong Tian, and Li Yuan. Masked autoencoders for point cloud self-supervised learning. In ECCV, 2022. 2, 3 +[30] Helmut Pottmann and Johannes Wallner. Computational line geometry. Springer, 2001. 3 +[31] Rui Qian, Shuangrui Ding, Xian Liu, and Dahua Lin. Static and dynamic concepts for self-supervised video representation learning. In ECCV, 2022. 4 +[32] Yongming Rao, Jiwen Lu, and Jie Zhou. Global-local bidirectional reasoning for unsupervised representation learning of 3D point clouds. In CVPR, 2020. 2 + +[33] Amir Shahroudy, Jun Liu, Tian-Tsong Ng, and Gang Wang. NTU RGB+D: A large scale dataset for 3D human activity analysis. In CVPR, 2016. 5 +[34] Zhiqiang Shen, Xiaoxiao Sheng, Longguang Wang, Yulan Guo, Qiong Liu, and Xi Zhou. Pointemp: Contrastive mask prediction for self-supervised learning on point cloud videos. In CVPR, 2023. 3 +[35] Xiaoxiao Sheng, Zhiqiang Shen, and Gang Xiao. Contrastive predictive autoencoders for dynamic point cloud self-supervised learning. In AAAI, 2023. 3 +[36] Karen Simonyan and Andrew Zisserman. Two-stream convolutional networks for action recognition in videos. In NeurIPS, 2014. 4 +[37] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. VideoMAE: Masked autoencoders are data-efficient learners for self-supervised video pre-training. In NeurIPS, 2022. 2, 4, 5 +[38] Haiyan Wang, Liang Yang, Xuejian Rong, Jinglun Feng, and Yingli Tian. Self-supervised 4D spatio-temporal feature learning via order prediction of sequential point cloud clips. In WACV, 2021. 3 +[39] Rui Wang, Dongdong Chen, Zuxuan Wu, Yinpeng Chen, Xiyang Dai, Mengchen Liu, Yu-Gang Jiang, Luowei Zhou, and Lu Yuan. BEVT: BERT pretraining of video transformers. In CVPR, 2022. 2 +[40] Yancheng Wang, Yang Xiao, Fu Xiong, Wenxiang Jiang, Zhiguo Cao, Joey Tianyi Zhou, and Junsong Yuan. 3DV: 3D dynamic voxel for action recognition in depth video. In CVPR, 2020. 1, 3, 6 +[41] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In CVPR, 2022. 2 +[42] Yimin Wei, Hao Liu, Tingting Xie, Qiuhong Ke, and Yulan Guo. Spatial-temporal transformer for 3D point cloud sequences. In WACV, 2022. 1, 3 +[43] Hao Wen, Yunze Liu, Jingwei Huang, Bo Duan, and Li Yi. Point primitive transformer for long-term 4D point cloud video understanding. In ECCV, 2022. 1, 3, 5 +[44] Saining Xie, Jiatao Gu, Demi Guo, Charles R Qi, Leonidas Guibas, and Or Litany. PointContrast: Unsupervised pretraining for 3D point cloud understanding. In ECCV, 2020. 2 +[45] Zhenda Xie, Zheng Zhang, Yue Cao, Yutong Lin, Jianmin Bao, Zhuliang Yao, Qi Dai, and Han Hu. SimMIM: A simple framework for masked image modeling. In CVPR, 2022. 2 +[46] Yaoqing Yang, Chen Feng, Yiru Shen, and Dong Tian. FoldingNet: Point cloud auto-encoder via deep grid deformation. In CVPR, 2018. 2 +[47] Xumin Yu, Lulu Tang, Yongming Rao, Tiejun Huang, Jie Zhou, and Jiwen Lu. Point-BERT: Pre-training 3D point cloud transformers with masked point modeling. In CVPR, 2022. 2, 3 +[48] Zhuoyang Zhang, Yuhao Dong, Yunze Liu, and Li Yi. Complete-to-partial 4D distillation for self-supervised point cloud sequence representation learning. arXiv preprint arXiv:2212.05330, 2022. 3 + +[49] Zaiwei Zhang, Rohit Girdhar, Armand Joulin, and Ishan Misra. Self-supervised pretraining of 3D features on any point-cloud. In ICCV, 2021. 2 +[50] Jia-Xing Zhong, Kaichen Zhou, Qingyong Hu, Bing Wang, Niki Trigoni, and Andrew Markham. No Pain, Big Gain: Classify dynamic point cloud sequences with static models by fitting feature-level space-time surfaces. In CVPR, 2022. 1, 3, 5, 6 \ No newline at end of file diff --git a/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/images.zip b/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..cbd7ee7309c5f1eb9f5beb78198d46ada0752493 --- /dev/null +++ b/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:3e8af08e8c2b581bd5fb1ea12742e2f7141fc86f928132e3feca2d151bf3194d +size 574579 diff --git a/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/layout.json b/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..101cee0f04b1575ae4af4e89be475272205b66b3 --- /dev/null +++ b/2023/Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos/layout.json @@ -0,0 +1,8854 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 64, + 102, + 531, + 138 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 64, + 102, + 531, + 138 + ], + "spans": [ + { + "bbox": [ + 64, + 102, + 531, + 138 + ], + "type": "text", + "content": "Masked Spatio-Temporal Structure Prediction for Self-supervised Learning on Point Cloud Videos" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "spans": [ + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": "Zhiqiang Shen" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{1,5*}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": ", Xiaoxiao Sheng" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": ", Hehe Fan" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{2\\dagger}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": ", Longguang Wang" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": ", Yulan Guo" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": ", Qiong Liu" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{5}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": ", Hao Wen" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{5}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": ", Xi Zhou" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{1,5}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": "Shanghai Jiao Tong University " + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": "Zhejiang University " + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": "Aviation University of Air Force " + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": "Sun Yat-sen University " + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "inline_equation", + "content": "^{5}" + }, + { + "bbox": [ + 75, + 160, + 520, + 217 + ], + "type": "text", + "content": "CloudWalk" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 244, + 192, + 258 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 244, + 192, + 258 + ], + "spans": [ + { + "bbox": [ + 143, + 244, + 192, + 258 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 270, + 290, + 547 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 270, + 290, + 547 + ], + "spans": [ + { + "bbox": [ + 47, + 270, + 290, + 547 + ], + "type": "text", + "content": "Recently, the community has made tremendous progress in developing effective methods for point cloud video understanding that learn from massive amounts of labeled data. However, annotating point cloud videos is usually notoriously expensive. Moreover, training via one or only a few traditional tasks (e.g., classification) may be insufficient to learn subtle details of the spatio-temporal structure existing in point cloud videos. In this paper, we propose a Masked Spatio-Temporal Structure Prediction (MaST-Pre) method to capture the structure of point cloud videos without human annotations. MaST-Pre is based on spatio-temporal point-tube masking and consists of two self-supervised learning tasks. First, by reconstructing masked point tubes, our method is able to capture the appearance information of point cloud videos. Second, to learn motion, we propose a temporal cardinality difference prediction task that estimates the change in the number of points within a point tube. In this way, MaST-Pre is forced to model the spatial and temporal structure in point cloud videos. Extensive experiments on MSRAction-3D, NTU-RGBD, NvGesture, and SHREC'17 demonstrate the effectiveness of the proposed method. The code is available at https://github.com/JohnsonSign/MaST-Pre." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 568, + 128, + 582 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 568, + 128, + 582 + ], + "spans": [ + { + "bbox": [ + 47, + 568, + 128, + 582 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 589, + 287, + 685 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 589, + 287, + 685 + ], + "spans": [ + { + "bbox": [ + 46, + 589, + 287, + 685 + ], + "type": "text", + "content": "In physics, motion is the phenomenon in which position changes over time. Because point clouds provide precise position information, i.e., 3D coordinates, point cloud videos, which evolve over time, can accurately describe the 3D motion in the real world. Effectively understanding point cloud videos can significantly improve intelligent agents on the interaction with environments. Therefore, the community has developed a few effective methods for" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 309, + 244, + 544, + 417 + ], + "blocks": [ + { + "bbox": [ + 309, + 244, + 544, + 417 + ], + "lines": [ + { + "bbox": [ + 309, + 244, + 544, + 417 + ], + "spans": [ + { + "bbox": [ + 309, + 244, + 544, + 417 + ], + "type": "image", + "image_path": "b40a14514a2720f9027a0ed9d71f7e3584cc5f0ec63cfe8e21642e0a7eb9394c.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 420, + 547, + 477 + ], + "lines": [ + { + "bbox": [ + 305, + 420, + 547, + 477 + ], + "spans": [ + { + "bbox": [ + 305, + 420, + 547, + 477 + ], + "type": "text", + "content": "Figure 1. Our MaST-Pre is based on spatio-temporal point-tube masking. To enable a model to capture the appearance structure in point cloud videos, we ask it to reconstruct masked point tubes. To equip the model with motion modeling ability, we develop a temporal cardinality difference prediction task." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 497, + 547, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 497, + 547, + 628 + ], + "spans": [ + { + "bbox": [ + 304, + 497, + 547, + 628 + ], + "type": "text", + "content": "point cloud video understanding, including video classification [9-12, 40, 50] and semantic segmentation [6, 24, 42, 43]. However, most of these methods are based on supervised learning and that requires much effort to carefully annotate massive amounts of labels. Moreover, learning via only classification or segmentation may make deep neural networks take too much emphasis on the task itself but largely ignore the subtle details of the instinct spatiotemporal structure in point cloud videos. To alleviate those problems, we propose a self-supervised learning method on point cloud videos." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 630, + 548, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 548, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 548, + 715 + ], + "type": "text", + "content": "Self-supervised learning uses supervisory signals from the data itself and enables deep neural networks to learn from massive data without human annotations. This is important to recognize more subtle patterns in data. Networks pre-trained with self-supervised learning usually yield higher performance than when solely trained in a supervised manner [5, 15, 16, 19]. Although self-supervised" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 693, + 174, + 703 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 693, + 174, + 703 + ], + "spans": [ + { + "bbox": [ + 58, + 693, + 174, + 703 + ], + "type": "text", + "content": "*These authors contributed equally." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 59, + 703, + 136, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 703, + 136, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 703, + 136, + 712 + ], + "type": "text", + "content": "† Corresponding author." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "16580" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 167 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 167 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 167 + ], + "type": "text", + "content": "learning has been applied to images [15], videos [13, 37] and static point clouds [29, 47], it has not been promoted on 4D signals, such as point cloud videos. Visual signals in point cloud videos can be divided into appearance and motion. While appearance specifies which objects are in videos, motion describes their dynamics. Therefore, self-supervised learning on point cloud videos should carefully make the most of the appearance and motion structure." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 169, + 288, + 337 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 169, + 288, + 337 + ], + "spans": [ + { + "bbox": [ + 46, + 169, + 288, + 337 + ], + "type": "text", + "content": "In this paper, we propose a Masked Spatio-Temporal Structure Prediction (MaST-Pre) method for self-supervised learning on point cloud videos (Fig. 1). MaST-Pre is based on a masking strategy, which has been proven effective in a range of applications. For example, because of the canonical structure, images can be easily segmented into multiple patches for masking [8, 15], which in the case of video are extended to patch tubes [13, 37]. For unstructured static point clouds, spherical support domain masking can be used for masked autoencoder [29, 47]. However, the spatial irregularity and temporal regularity make point cloud videos require a more elaborate masking strategy. Our method is based on a masked point tube mechanism, where a point tube is a local area expanding over a short time [11]." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 338, + 288, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 338, + 288, + 529 + ], + "spans": [ + { + "bbox": [ + 46, + 338, + 288, + 529 + ], + "type": "text", + "content": "Based on point-tube masking, our MaST-Pre employs two self-supervised tasks to capture the appearance and motion structure, respectively. First, to learn the appearance structure, MaST-Pre is asked to predict the invisible parts of the input from unmasked points. Second, to capture the dynamics in point tubes, we propose the temporal cardinality difference, which can be calculated online from inputs without additional parameters. Cardinality can reflect basic structures (e.g., line, edge, and plane) of static point clouds [21]. In this paper, we extend it to a temporal version so that it can model the dynamics of point cloud videos. Intuitively, the temporal cardinality difference characterizes the flow of points within a short time. Therefore, inferring the temporal cardinality difference of masked point tubes facilitates MaST-Pre to learn motion-informative representations. Our contributions are summarized as follows:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 58, + 542, + 287, + 698 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 59, + 542, + 287, + 591 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 542, + 287, + 591 + ], + "spans": [ + { + "bbox": [ + 59, + 542, + 287, + 591 + ], + "type": "text", + "content": "- We design a 4D scheme of masked prediction for self-supervised learning on point cloud videos, termed as MaST-Pre. Our MaST-Pre jointly learns the appearance and motion structure of point cloud videos." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 58, + 602, + 287, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 602, + 287, + 651 + ], + "spans": [ + { + "bbox": [ + 58, + 602, + 287, + 651 + ], + "type": "text", + "content": "- We propose the temporal cardinality difference, a simple and effective motion feature directly captured from raw input points. It explicitly guides MaST-Pre to learn motion-informative representations." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 58, + 662, + 287, + 698 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 662, + 287, + 698 + ], + "spans": [ + { + "bbox": [ + 58, + 662, + 287, + 698 + ], + "type": "text", + "content": "- Extensive experiments and ablation studies on several benchmark datasets validate that our MaST-Pre learns rich representations of point cloud videos." + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 71, + 392, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 71, + 392, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 71, + 392, + 84 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 91, + 545, + 140 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 91, + 545, + 140 + ], + "spans": [ + { + "bbox": [ + 304, + 91, + 545, + 140 + ], + "type": "text", + "content": "In this section, we first briefly review visual mask prediction for self-supervised learning. Then, we present recent advances in self-supervised learning on point clouds and dynamics modeling for point cloud videos." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 144, + 440, + 156 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 144, + 440, + 156 + ], + "spans": [ + { + "bbox": [ + 306, + 144, + 440, + 156 + ], + "type": "text", + "content": "2.1. Visual Mask Prediction" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 163, + 545, + 270 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 163, + 545, + 270 + ], + "spans": [ + { + "bbox": [ + 304, + 163, + 545, + 270 + ], + "type": "text", + "content": "Mask prediction has been proven to be an excellent self-supervised task for visual representation learning [8,15,45]. By reconstructing target signals from the masked input, mask prediction enables the network to learn rich representations and boosts self-supervised learning [2,4,39,41]. Chen et al. [4] extended GPT [3] to operate the pixel sequence for prediction. Bao et al. [2] and Wang et al. [39] introduced another successful framework, BERT [19], to predict the identities of masked tokens." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 270, + 546, + 439 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 270, + 546, + 439 + ], + "spans": [ + { + "bbox": [ + 304, + 270, + 546, + 439 + ], + "type": "text", + "content": "Then, He et al. [15] proposed MAE as a scalable vision learner to predict the pixels of masked patches. Feichtenhofer et al. [13] and Tong et al. [37] extended MAE to video representation learning by masking patch tubes. Wei et al. [41] developed MaskFeat to predict the HOG features of masked spatio-temporal tubes for self-supervised video pretraining. The regular structure of images and videos makes it easy to obtain patches or patch tubes, which facilitates the design of masking strategies. Pang et al. [29] extended MAE to unstructured static point clouds and designed a masking strategy based on the local spatial neighborhoods. However, point cloud videos are not only spatially irregular but also temporally misaligned across frames [9, 11]. To remedy this, we design a point-tube masking strategy." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 444, + 523, + 456 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 444, + 523, + 456 + ], + "spans": [ + { + "bbox": [ + 306, + 444, + 523, + 456 + ], + "type": "text", + "content": "2.2. Self-supervised Learning on Point Clouds" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 463, + 545, + 654 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 463, + 545, + 654 + ], + "spans": [ + { + "bbox": [ + 304, + 463, + 545, + 654 + ], + "type": "text", + "content": "Contrastive learning has made significant progress on static point clouds [17, 32, 44, 49]. Xie et al. [44] proposed PointContrast to discriminate two geometric views of matched points using contrastive loss. Hou et al. [17] introduced contextual contrastive learning to PointContrast for data-efficient point pre-training. Rao et al. [32] mapped the local and global features to shared representation space and applied a contrastive loss on them. Zhang et al. [49] used the instance discrimination task on two augmented versions of a point cloud, while Huang et al. [18] pre-trained static point clouds using spatio-temporal augmentations. They transformed different views at point, region, object, and scene levels, and then used contrastive learning to judge their semantic consistency. However, there are limited augmentation methods that can guarantee the semantic consistency of point clouds, let alone point cloud videos." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 654, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 545, + 715 + ], + "type": "text", + "content": "Prediction-based methods on point clouds also attract a lot of attention. Yang et al. [46] proposed a folding-based autoencoder that deforms a 2D grid to reconstruct the target 3D point cloud. Recently, mask prediction has been extended to static point clouds. Liu et al. [22] designed a point" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16581" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 58, + 70, + 534, + 238 + ], + "blocks": [ + { + "bbox": [ + 58, + 70, + 534, + 238 + ], + "lines": [ + { + "bbox": [ + 58, + 70, + 534, + 238 + ], + "spans": [ + { + "bbox": [ + 58, + 70, + 534, + 238 + ], + "type": "image", + "image_path": "dad6bc8cee570461f85a6ff64696d5f6822c600719193bde0ee7de9205b7b572.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 243, + 546, + 277 + ], + "lines": [ + { + "bbox": [ + 46, + 243, + 546, + 277 + ], + "spans": [ + { + "bbox": [ + 46, + 243, + 546, + 277 + ], + "type": "text", + "content": "Figure 2. Illustration of the proposed MaST-Pre method. First, given a point cloud video, MaST-Pre divides it into several point tubes and masks part of them. Then, based on an encoder-decoder architecture, MaST-Pre attempts to recover masked point tubes and predict their temporal cardinality difference." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 296, + 289, + 403 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 296, + 289, + 403 + ], + "spans": [ + { + "bbox": [ + 46, + 296, + 289, + 403 + ], + "type": "text", + "content": "discrimination task for masked patches. Yu et al. [47] proposed PointBERT with an offline point tokenizer. Pang et al. [29] used a simpler task, reconstructing masked point coordinates, for point pre-training in an end-to-end manner. However, these methods solely focus on the geometric representation learning of static point clouds. In this paper, on top of learning appearance information, an explicit motion information learning method is designed for point cloud videos." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 416, + 272, + 430 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 416, + 272, + 430 + ], + "spans": [ + { + "bbox": [ + 47, + 416, + 272, + 430 + ], + "type": "text", + "content": "2.3. Dynamics Modeling for Point Cloud Videos" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 437, + 287, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 437, + 287, + 604 + ], + "spans": [ + { + "bbox": [ + 46, + 437, + 287, + 604 + ], + "type": "text", + "content": "Supervised learning dominates point cloud video research. [11, 12] and [9, 10, 42, 43] use convolution-based methods and attention-based methods to implicitly learn the long-term features of point cloud videos, respectively. In addition, [24, 40, 50] apply empirical-based dynamics methods modeling point cloud videos. Wang et al. [40] introduced temporal rank pooling [14] to capture the frame-level dynamics. Zhong et al. [50] proposed a two-stream framework and used feature-level ST-surfaces [30] in the dynamics learning branch. Liu et al. [24] used a scene flow estimator [23] or an alternative grouping method to do point tracking for dynamics modeling. Although these methods are effective, they require complex calculations or additional modules." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "content": "Self-supervised learning on point cloud videos is understudied [34, 35]. Wang et al. [38] pre-trained the encoder by predicting the temporal order of shuffled segments to learn the dynamics of point cloud videos. Zhang et al. [48] developed complete-to-partial 4D distillation to predict the representations of point cloud frames within a short time window. However, these methods learn motion information using clip-level or frame-level pretext tasks. In this paper, we propose the temporal cardinality difference prediction" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 297, + 537, + 308 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 297, + 537, + 308 + ], + "spans": [ + { + "bbox": [ + 306, + 297, + 537, + 308 + ], + "type": "text", + "content": "for fine-grained dynamics learning on point cloud videos." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 319, + 361, + 331 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 319, + 361, + 331 + ], + "spans": [ + { + "bbox": [ + 306, + 319, + 361, + 331 + ], + "type": "text", + "content": "3. Method" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 339, + 545, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 339, + 545, + 495 + ], + "spans": [ + { + "bbox": [ + 304, + 339, + 545, + 495 + ], + "type": "text", + "content": "The architecture of our MaST-Pre is illustrated in Fig. 2. Given a point cloud video, it is first divided into multiple point tubes. Next, a masking operation is performed, separating these point tubes into visible and invisible parts. The visible ones are fed to an encoder, and then their updated embeddings are fed to the decoder along with the masked point tubes. Afterward, two-stream prediction tasks are implemented to recover the point coordinates within masked point tubes and to infer their temporal cardinality differences, respectively. Intuitively, enabling the decoder to perform well on two-stream prediction tasks demands the encoder to learn representations rich in appearance and motion information jointly." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 503, + 411, + 516 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 503, + 411, + 516 + ], + "spans": [ + { + "bbox": [ + 306, + 503, + 411, + 516 + ], + "type": "text", + "content": "3.1. Masking Strategy" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 521, + 544, + 545 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 521, + 544, + 545 + ], + "spans": [ + { + "bbox": [ + 305, + 521, + 544, + 545 + ], + "type": "text", + "content": "The masking strategy includes three steps: input division, embedding, and masking operation." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": "Division. Point tubes are introduced as division units of the input point cloud video. Specifically, given a point cloud video " + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "inline_equation", + "content": "\\pmb{P}" + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": ", Farthest Point Sampling is used to select " + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": " key points " + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "inline_equation", + "content": "\\hat{\\pmb{p}}" + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": " from the input. Next, we construct one point tube for each key point. The point tube centered at " + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": "-th key point " + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "inline_equation", + "content": "\\hat{p}_i" + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": " is denoted as " + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "inline_equation", + "content": "\\pmb{T}\\pmb{u}\\pmb{e}_{\\hat{p}_i} = \\{p \\mid p \\in \\pmb{P}, \\mathcal{D}_s(p, \\hat{p}_i) < r, \\mathcal{D}_t(p, \\hat{p}_i) < \\frac{l}{2}\\}" + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": " is one of the input points, " + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_s" + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": " is the Euclidean distance, " + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_t" + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": " is the difference in frame timestamps of two points, " + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": " is the radius of a spatial neighborhood and " + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": " is the number of frames in a point tube. Then, we use random sampling to select " + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 304, + 546, + 545, + 689 + ], + "type": "text", + "content": " points in each spatial neighborhood." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": "In this way, a point cloud video is divided into " + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": " point tubes, and each point tube contains " + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "inline_equation", + "content": "l \\times n" + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": " points. To en" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16582" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 70, + 312, + 244 + ], + "blocks": [ + { + "bbox": [ + 49, + 70, + 312, + 244 + ], + "lines": [ + { + "bbox": [ + 49, + 70, + 312, + 244 + ], + "spans": [ + { + "bbox": [ + 49, + 70, + 312, + 244 + ], + "type": "image", + "image_path": "8defb88c45c42b96b704055e14bff5a18eb9ff14f4944abf73fc46700d127cc9.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 136, + 248, + 241, + 260 + ], + "lines": [ + { + "bbox": [ + 136, + 248, + 241, + 260 + ], + "spans": [ + { + "bbox": [ + 136, + 248, + 241, + 260 + ], + "type": "text", + "content": "(a) Cardinality Histogram" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 62, + 272, + 116, + 282 + ], + "lines": [ + { + "bbox": [ + 62, + 272, + 116, + 282 + ], + "spans": [ + { + "bbox": [ + 62, + 272, + 116, + 282 + ], + "type": "text", + "content": "I " + }, + { + "bbox": [ + 62, + 272, + 116, + 282 + ], + "type": "inline_equation", + "content": "\\sim" + }, + { + "bbox": [ + 62, + 272, + 116, + 282 + ], + "type": "text", + "content": " VIII Octant" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_footnote" + }, + { + "bbox": [ + 133, + 273, + 156, + 281 + ], + "lines": [ + { + "bbox": [ + 133, + 273, + 156, + 281 + ], + "spans": [ + { + "bbox": [ + 133, + 273, + 156, + 281 + ], + "type": "text", + "content": "-·-·" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_footnote" + }, + { + "bbox": [ + 160, + 274, + 172, + 281 + ], + "lines": [ + { + "bbox": [ + 160, + 274, + 172, + 281 + ], + "spans": [ + { + "bbox": [ + 160, + 274, + 172, + 281 + ], + "type": "text", + "content": "Oct" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_footnote" + }, + { + "bbox": [ + 176, + 274, + 233, + 282 + ], + "lines": [ + { + "bbox": [ + 176, + 274, + 233, + 282 + ], + "spans": [ + { + "bbox": [ + 176, + 274, + 233, + 282 + ], + "type": "text", + "content": "ant Central Line" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_footnote" + }, + { + "bbox": [ + 252, + 274, + 274, + 281 + ], + "lines": [ + { + "bbox": [ + 252, + 274, + 274, + 281 + ], + "spans": [ + { + "bbox": [ + 252, + 274, + 274, + 281 + ], + "type": "text", + "content": "#" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_footnote" + }, + { + "bbox": [ + 278, + 274, + 305, + 281 + ], + "lines": [ + { + "bbox": [ + 278, + 274, + 305, + 281 + ], + "spans": [ + { + "bbox": [ + 278, + 274, + 305, + 281 + ], + "type": "text", + "content": "Points" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_footnote" + }, + { + "bbox": [ + 129, + 295, + 463, + 306 + ], + "lines": [ + { + "bbox": [ + 129, + 295, + 463, + 306 + ], + "spans": [ + { + "bbox": [ + 129, + 295, + 463, + 306 + ], + "type": "text", + "content": "Figure 3. Illustration of Cardinality Histogram (a) and Temporal Cardinality Difference (b)." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 326, + 71, + 544, + 244 + ], + "blocks": [ + { + "bbox": [ + 326, + 71, + 544, + 244 + ], + "lines": [ + { + "bbox": [ + 326, + 71, + 544, + 244 + ], + "spans": [ + { + "bbox": [ + 326, + 71, + 544, + 244 + ], + "type": "image", + "image_path": "20ca32a24269e34bf21bac915d8dea42c334d81c44700f53ad35efbede127f12.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 361, + 248, + 509, + 260 + ], + "lines": [ + { + "bbox": [ + 361, + 248, + 509, + 260 + ], + "spans": [ + { + "bbox": [ + 361, + 248, + 509, + 260 + ], + "type": "text", + "content": "(b) Temporal Cardinality Difference" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 327, + 273, + 361, + 283 + ], + "lines": [ + { + "bbox": [ + 327, + 273, + 361, + 283 + ], + "spans": [ + { + "bbox": [ + 327, + 273, + 361, + 283 + ], + "type": "inline_equation", + "content": "d_{1}d_{2}d_{3}d_{4}" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_footnote" + }, + { + "bbox": [ + 364, + 273, + 514, + 283 + ], + "lines": [ + { + "bbox": [ + 364, + 273, + 514, + 283 + ], + "spans": [ + { + "bbox": [ + 364, + 273, + 514, + 283 + ], + "type": "text", + "content": "Angular Distance to Octant Central Line" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_footnote" + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 326, + 287, + 350 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 326, + 287, + 350 + ], + "spans": [ + { + "bbox": [ + 46, + 326, + 287, + 350 + ], + "type": "text", + "content": "sure all points are covered by point tubes, " + }, + { + "bbox": [ + 46, + 326, + 287, + 350 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 46, + 326, + 287, + 350 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 326, + 287, + 350 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 46, + 326, + 287, + 350 + ], + "type": "text", + "content": " are set to maintain a minor overlap between adjacent point tubes." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 350, + 287, + 373 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 350, + 287, + 373 + ], + "spans": [ + { + "bbox": [ + 46, + 350, + 287, + 373 + ], + "type": "text", + "content": "**Embedding.** Following our baseline [9], each point tube is encoded into an embedding:" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 100, + 380, + 287, + 418 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 100, + 380, + 287, + 418 + ], + "spans": [ + { + "bbox": [ + 100, + 380, + 287, + 418 + ], + "type": "interline_equation", + "content": "\\boldsymbol {E} _ {\\hat {p} _ {i}} = \\sum_ {t = 1} ^ {l} \\sum_ {p \\in \\boldsymbol {T u b e} _ {\\hat {p} _ {i}} ^ {t}} f (p - \\hat {p} _ {i}), \\tag {1}", + "image_path": "75f147822c7febd11ed42a7935e2c08d313bf7f9458649f2e9f08889a223f5fd.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 46, + 425, + 287, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 425, + 287, + 460 + ], + "spans": [ + { + "bbox": [ + 46, + 425, + 287, + 460 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 425, + 287, + 460 + ], + "type": "inline_equation", + "content": "\\mathbf{Tube}_{\\hat{p}_i}^t" + }, + { + "bbox": [ + 46, + 425, + 287, + 460 + ], + "type": "text", + "content": " is the " + }, + { + "bbox": [ + 46, + 425, + 287, + 460 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 425, + 287, + 460 + ], + "type": "text", + "content": "-th frame of the point tube centered at " + }, + { + "bbox": [ + 46, + 425, + 287, + 460 + ], + "type": "inline_equation", + "content": "\\hat{p}_i" + }, + { + "bbox": [ + 46, + 425, + 287, + 460 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 425, + 287, + 460 + ], + "type": "inline_equation", + "content": "f(\\cdot)" + }, + { + "bbox": [ + 46, + 425, + 287, + 460 + ], + "type": "text", + "content": " is an MLP-based feature extractor. More details can be found in [9]." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 46, + 461, + 287, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 461, + 287, + 594 + ], + "spans": [ + { + "bbox": [ + 46, + 461, + 287, + 594 + ], + "type": "text", + "content": "Masking. The design of the masking operation is related to the information redundancy of input [13, 15, 37]. Because of spatio-temporal coherence, the redundancy of the point cloud video is higher than low-dimensional data. Therefore, our MaST-Pre uses a high masking ratio on point cloud videos and the empirical result is " + }, + { + "bbox": [ + 46, + 461, + 287, + 594 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 46, + 461, + 287, + 594 + ], + "type": "text", + "content": ". A high ratio is helpful to alleviate information leakage and make reconstruction a meaningful self-supervised task. In addition, our MaST-Pre uses random masking of point tubes. As a spacetime-agnostic method, random masking is more effective than structure-aware strategies [13]." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 47, + 599, + 135, + 612 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 599, + 135, + 612 + ], + "spans": [ + { + "bbox": [ + 47, + 599, + 135, + 612 + ], + "type": "text", + "content": "3.2. Autoencoding" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 46, + 617, + 287, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 287, + 653 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 287, + 653 + ], + "type": "text", + "content": "Our autoencoder is based on vanilla Transformers of point cloud videos [9]. An asymmetric encoder-decoder design is introduced to MaST-Pre." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 46, + 653, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 287, + 713 + ], + "type": "text", + "content": "Encoder. To better capture the dynamics of point cloud videos, joint spatio-temporal attention is adopted [1,25]. In addition, only the visible point tubes with spatio-temporal positional embeddings are fed into the encoder during pretraining." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 304, + 326, + 547, + 410 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 326, + 547, + 410 + ], + "spans": [ + { + "bbox": [ + 304, + 326, + 547, + 410 + ], + "type": "text", + "content": "Decoder. The decoder is similar to our encoder but a lightweight vanilla Transformer [9]. It takes both encoded point tubes and masked ones as input. By adding a full set of spatio-temporal positional embeddings to all tokens, location clues are provided for self-supervised learning. After decoding, only the embeddings of masked point tubes are fed to the following prediction heads." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 306, + 417, + 436, + 429 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 417, + 436, + 429 + ], + "spans": [ + { + "bbox": [ + 306, + 417, + 436, + 429 + ], + "type": "text", + "content": "3.3. Two-stream Prediction" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 435, + 547, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 435, + 547, + 495 + ], + "spans": [ + { + "bbox": [ + 304, + 435, + 547, + 495 + ], + "type": "text", + "content": "It is demonstrated in [31, 36] that effective video representation integrates appearance and motion information. Therefore, two-stream self-supervised tasks are proposed to explicitly predict motions and reconstruct the appearance of masked point cloud videos." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 304, + 495, + 547, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 495, + 547, + 544 + ], + "spans": [ + { + "bbox": [ + 304, + 495, + 547, + 544 + ], + "type": "text", + "content": "Appearance Stream. The reconstruction objectives are the point coordinates of masked point tubes. The " + }, + { + "bbox": [ + 304, + 495, + 547, + 544 + ], + "type": "inline_equation", + "content": "l_{2}" + }, + { + "bbox": [ + 304, + 495, + 547, + 544 + ], + "type": "text", + "content": " Chamber Distance loss is used between predictions " + }, + { + "bbox": [ + 304, + 495, + 547, + 544 + ], + "type": "inline_equation", + "content": "P_{pre} \\in \\mathbb{R}^{l \\times n \\times 3}" + }, + { + "bbox": [ + 304, + 495, + 547, + 544 + ], + "type": "text", + "content": " and the ground truth " + }, + { + "bbox": [ + 304, + 495, + 547, + 544 + ], + "type": "inline_equation", + "content": "P_{gt} \\in \\mathbb{R}^{l \\times n \\times 3}" + }, + { + "bbox": [ + 304, + 495, + 547, + 544 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 320, + 552, + 545, + 633 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 320, + 552, + 545, + 633 + ], + "spans": [ + { + "bbox": [ + 320, + 552, + 545, + 633 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {L} _ {a p p} = \\frac {1}{l} \\sum_ {i = 1} ^ {l} \\left\\{\\frac {1}{| \\boldsymbol {P} _ {p r e} ^ {i} |} \\sum_ {a \\in \\boldsymbol {P} _ {p r e} ^ {i}} \\min _ {b \\in \\boldsymbol {P} _ {g t} ^ {i}} \\| a - b \\| _ {2} ^ {2} + \\right. \\tag {2} \\\\ \\left. \\frac {1}{| \\boldsymbol {P} _ {g t} ^ {i} |} \\sum_ {b \\in \\boldsymbol {P} _ {g t} ^ {i}} \\min _ {a \\in \\boldsymbol {P} _ {p r e} ^ {i}} \\| b - a \\| _ {2} ^ {2} \\right\\}. \\\\ \\end{array}", + "image_path": "b0469f1ddcddef13decdc945c52c3ac5570d92bf59cba6eea2a23e4129b0a01c.jpg" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 304, + 641, + 547, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 547, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 547, + 712 + ], + "type": "text", + "content": "Motion Stream. We propose the temporal cardinality difference as the target of the motion prediction stream. As shown in Fig. 3(a), the spherical support domain of the key point is divided into 8 octants. We follow the conventional rule that the area where the " + }, + { + "bbox": [ + 304, + 641, + 547, + 712 + ], + "type": "inline_equation", + "content": "xyz" + }, + { + "bbox": [ + 304, + 641, + 547, + 712 + ], + "type": "text", + "content": "-coordinates are greater than 0 is the first octant I and then increases counterclockwise." + } + ] + } + ], + "index": 26 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16583" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "text", + "content": "Then, count the cardinality of each octant into the corresponding bin of a histogram. To alleviate the noise in real-world point clouds, a probabilistic approach is employed. Specifically, calculate the angular distance " + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "text", + "content": " of each point to the central line of its current octant, and divide it by " + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "inline_equation", + "content": "90^{\\circ}" + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "text", + "content": " to normalize. For example, the current octant of Point2 (the green one in Fig. 3(a)) is octant III. The angular difference " + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "inline_equation", + "content": "d2" + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "text", + "content": " between Point2 and the central dashed line of octant III is " + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "inline_equation", + "content": "30^{\\circ}" + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "text", + "content": ". Consequently, the probabilities of Point2 belonging to octant IV and III are " + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "inline_equation", + "content": "\\frac{1}{3}" + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "text", + "content": " (i.e., " + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "inline_equation", + "content": "\\frac{30^{\\circ}}{90^{\\circ}}" + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "text", + "content": ") and " + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "inline_equation", + "content": "\\frac{2}{3}" + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "text", + "content": " (i.e., " + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "inline_equation", + "content": "\\frac{60^{\\circ}}{90^{\\circ}}" + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "text", + "content": "), respectively. In particular, when a point falls on an axis (e.g., the " + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "inline_equation", + "content": "-y" + }, + { + "bbox": [ + 46, + 72, + 289, + 227 + ], + "type": "text", + "content": " axis), its probabilities belonging to octant IV and III are both 0.5." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "spans": [ + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "text", + "content": "Next, as shown in Fig. 3(b), the cardinality histograms " + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "inline_equation", + "content": "C \\in \\mathbb{R}^8" + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "text", + "content": " between adjacent frames of a point tube are subtracted to obtain its temporal cardinality difference " + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "inline_equation", + "content": "CD \\in \\mathbb{R}^8" + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "text", + "content": ", which constitutes the ground truth " + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "inline_equation", + "content": "M_{gt} \\in \\mathbb{R}^{(l-1) \\times 8}" + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "text", + "content": " of the motion stream. The decoded embeddings of masked point tubes are passed through a linear layer to obtain the motion prediction " + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "inline_equation", + "content": "M_{pre} \\in \\mathbb{R}^{(l-1) \\times 8}" + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "text", + "content": ". The smooth " + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "inline_equation", + "content": "l_1" + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "text", + "content": " loss of " + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "text", + "content": "-th " + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "inline_equation", + "content": "CD" + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "text", + "content": " between prediction and ground truth is denoted as " + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_m^i" + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "text", + "content": ". The loss of our motion stream is denoted as " + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{motion}" + }, + { + "bbox": [ + 47, + 228, + 289, + 337 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 52, + 346, + 287, + 377 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 346, + 287, + 377 + ], + "spans": [ + { + "bbox": [ + 52, + 346, + 287, + 377 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {m} ^ {i} = \\left\\{ \\begin{array}{l l} 0. 5 \\times \\left(M _ {p r e} ^ {i} - M _ {g t} ^ {i}\\right) ^ {2}, & \\text {i f} \\left| M _ {p r e} ^ {i} - M _ {g t} ^ {i} \\right| < 1 \\\\ \\left| M _ {p r e} ^ {i} - M _ {g t} ^ {i} \\right| - 0. 5, & \\text {o t h e r w i s e} \\end{array} , \\right. \\tag {3}", + "image_path": "d4f5433186960128b21cb6ad3d99f0b3fd257fa0ac96f297bcb0ae9a3d16bde2.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 115, + 389, + 287, + 422 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 115, + 389, + 287, + 422 + ], + "spans": [ + { + "bbox": [ + 115, + 389, + 287, + 422 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {m o t i o n}} = \\frac {1}{l - 1} \\sum_ {i = 1} ^ {l - 1} \\mathcal {L} _ {m} ^ {i}. \\tag {4}", + "image_path": "bfe97f60bb9386294e692d815b2eb22500660f5a9a7e651d1ff5b682d45cbc9e.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 59, + 428, + 272, + 439 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 428, + 272, + 439 + ], + "spans": [ + { + "bbox": [ + 59, + 428, + 272, + 439 + ], + "type": "text", + "content": "Overall, the total loss of our MaST-Pre is defined as:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 112, + 450, + 287, + 464 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 112, + 450, + 287, + 464 + ], + "spans": [ + { + "bbox": [ + 112, + 450, + 287, + 464 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\text {a p p}} + \\mathcal {L} _ {\\text {m o t i o n}}. \\tag {5}", + "image_path": "41049cad585a77160f7ee4644da6c2604bb0cd803cd46507f3b8490db4fd5e49.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 473, + 287, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 473, + 287, + 498 + ], + "spans": [ + { + "bbox": [ + 47, + 473, + 287, + 498 + ], + "type": "text", + "content": "With both loss terms, our MaST-Pre can simultaneously learn the geometry and dynamics of point cloud videos." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 510, + 128, + 522 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 510, + 128, + 522 + ], + "spans": [ + { + "bbox": [ + 47, + 510, + 128, + 522 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 529, + 287, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 529, + 287, + 601 + ], + "spans": [ + { + "bbox": [ + 46, + 529, + 287, + 601 + ], + "type": "text", + "content": "Our experiments are conducted on four point cloud video datasets. Following [13, 15, 37], we implement end-to-end fine-tuning, semi-supervised learning, and transfer learning to evaluate the pre-trained MaST-Pre. Afterward, ablation studies are conducted to analyze the design of our MaST-Pre and show the visualization results." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 610, + 110, + 622 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 610, + 110, + 622 + ], + "spans": [ + { + "bbox": [ + 47, + 610, + 110, + 622 + ], + "type": "text", + "content": "4.1. Datasets" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 629, + 287, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 287, + 677 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 287, + 677 + ], + "type": "text", + "content": "In this paper, to demonstrate the effectiveness of our spatio-temporal representations, we focus on long-term point cloud video tasks, including 4D action recognition and 4D gesture recognition." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": "MSRAction-3D [20] and NTU-RGBD [33] are utilized for the action recognition task. (1) MSRAction-3D is comprised of 567 videos in 20 daily actions. The average" + } + ] + } + ], + "index": 11 + }, + { + "type": "table", + "bbox": [ + 307, + 80, + 545, + 208 + ], + "blocks": [ + { + "bbox": [ + 321, + 69, + 529, + 79 + ], + "lines": [ + { + "bbox": [ + 321, + 69, + 529, + 79 + ], + "spans": [ + { + "bbox": [ + 321, + 69, + 529, + 79 + ], + "type": "text", + "content": "Table 1. Action recognition accuracy on MSRAction-3D." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 307, + 80, + 545, + 208 + ], + "lines": [ + { + "bbox": [ + 307, + 80, + 545, + 208 + ], + "spans": [ + { + "bbox": [ + 307, + 80, + 545, + 208 + ], + "type": "table", + "html": "
MethodsAccuracy (%)
Supervised LearningMeteorNet [24]88.50
PSTNet [11]91.20
PSTNet++ [12]92.68
Kinet [50]93.27
PPTr [43]92.33
P4Transformer [9]90.94
PST-Transformer [10]93.73
End-to-end Fine-tuningP4Transformer + MaST-Pre91.29
PST-Transformer + MaST-Pre94.08
", + "image_path": "b0267a0a46ddf3737421ad2f50f3625cc63730be11db54ecedfc37f6575adde9.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_body" + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 238, + 545, + 321 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 238, + 545, + 321 + ], + "spans": [ + { + "bbox": [ + 304, + 238, + 545, + 321 + ], + "type": "text", + "content": "frame number contained in each video is about 40. Following [9, 10], 270 videos are used as the training set and 297 videos are adopted as the test data. (2) NTU-RGBD consists of 56,880 videos with 60 fine-grained action categories. The frame number of each video is about 30 to 300. Under the cross-subject setting [33], 40,320 training videos and 16,560 test videos are used." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 327, + 546, + 411 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 327, + 546, + 411 + ], + "spans": [ + { + "bbox": [ + 304, + 327, + 546, + 411 + ], + "type": "text", + "content": "SHREC'17 [7] and NvGesture [28] are utilized for the gesture recognition task. (1) SHREC'17 is comprised of 2800 videos in 28 gestures. Following [7], this dataset is split into 1960 training videos and 840 test videos. (2) NvGesture consists of 1532 videos with 25 gesture classes. Following [27], 1050 videos are assigned to the training set and the remaining 482 videos to the test set." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 434, + 388, + 447 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 434, + 388, + 447 + ], + "spans": [ + { + "bbox": [ + 306, + 434, + 388, + 447 + ], + "type": "text", + "content": "4.2. Pre-training" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 457, + 545, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 457, + 545, + 601 + ], + "spans": [ + { + "bbox": [ + 304, + 457, + 545, + 601 + ], + "type": "text", + "content": "During pre-training, given a point cloud video, 24 frames are densely sampled and 1024 points are selected for each frame. Following [9, 10], the frame sampling stride is set to 2/1 on NTU-RGBD/MSRAction-3D and only random scaling is employed for data augmentation. For division and embedding, the temporal downsampling rate is set to 2 and the temporal kernel size " + }, + { + "bbox": [ + 304, + 457, + 545, + 601 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 304, + 457, + 545, + 601 + ], + "type": "text", + "content": " of each point tube is set to 3. Meanwhile, the spatial downsampling rate is set to 32. The radius of each support domain " + }, + { + "bbox": [ + 304, + 457, + 545, + 601 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 304, + 457, + 545, + 601 + ], + "type": "text", + "content": " is set to 0.1/0.3 on NTU-RGBD/MSRAction-3D and the number of neighbor points " + }, + { + "bbox": [ + 304, + 457, + 545, + 601 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 304, + 457, + 545, + 601 + ], + "type": "text", + "content": " within the spherical query is set to 32. The masking ratio is set to " + }, + { + "bbox": [ + 304, + 457, + 545, + 601 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 304, + 457, + 545, + 601 + ], + "type": "text", + "content": " unless otherwise specified." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 605, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 546, + 714 + ], + "type": "text", + "content": "P4Transformer [9] is utilized as our encoder, which consists of 10/5 layers of vanilla Transformers on NTU-RGBD/MSRAction-3D. The decoder is a 4-layer transformer. To verify the extensibility, PST-Transformer [10] is also used as an encoder on MSRAction-3D. Our MaST-Pre is pre-trained for 200 epochs and linear warmup is utilized for the first 10 epochs. The AdamW optimizer is used with a batch size of 128, and the initial learning rate is set to 0.001 with a cosine decay strategy." + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "16584" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 47, + 91, + 287, + 218 + ], + "blocks": [ + { + "bbox": [ + 47, + 69, + 287, + 91 + ], + "lines": [ + { + "bbox": [ + 47, + 69, + 287, + 91 + ], + "spans": [ + { + "bbox": [ + 47, + 69, + 287, + 91 + ], + "type": "text", + "content": "Table 2. Action recognition accuracy (%) on NTU-RGBD under cross-subject setting." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 47, + 91, + 287, + 218 + ], + "lines": [ + { + "bbox": [ + 47, + 91, + 287, + 218 + ], + "spans": [ + { + "bbox": [ + 47, + 91, + 287, + 218 + ], + "type": "table", + "html": "
MethodsAcc.
3DV-Motion [40]84.5
3DV-PointNet++ [40]88.8
PSTNet [11]90.5
PSTNet++ [12]91.4
Kinet [50]92.3
P4Transformer [9]90.2
PST-Transformer [10]91.0
P4Transformer + MaST-Pre (End-to-end Fine-tuning)90.8
P4Transformer + MaST-Pre (50% Semi-supervised)87.8
", + "image_path": "9e958dc1832dc616d4eb9b29c34459f92d08dc04d27949ed942bfb50bee6a814.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 239, + 180, + 251 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 239, + 180, + 251 + ], + "spans": [ + { + "bbox": [ + 47, + 239, + 180, + 251 + ], + "type": "text", + "content": "4.3. End-to-end Fine-tuning" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 256, + 287, + 327 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 256, + 287, + 327 + ], + "spans": [ + { + "bbox": [ + 46, + 256, + 287, + 327 + ], + "type": "text", + "content": "We first evaluate our MaST-Pre by fine-tuning the pretrained encoder with a new classifier in a supervised manner. End-to-end fine-tuning experiments are conducted on NTU-RGBD and MSRAction-3D, respectively. In each experiment, the same dataset is used for pre-training and fine-tuning." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 328, + 287, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 328, + 287, + 495 + ], + "spans": [ + { + "bbox": [ + 46, + 328, + 287, + 495 + ], + "type": "text", + "content": "MSRAction-3D. During fine-tuning, 24 frames are densely sampled and 2048 points are selected in each frame. Following [11], the spatial search radius is set to 0.7. The model is trained for 50 epochs with a batch size of 12 on 4 GPUs. We use the AdamW optimizer and the initial learning rate is set to 0.001 with a cosine decay strategy. As shown in Table 1, compared with baselines trained in a fully supervised manner, our MaST-Pre introduces accuracy improvements for both P4Transformer and PST-Transformer. According to prior experience, the masked autoencoder needs to be fed a considerable amount of data in the pretraining stage to learn useful knowledge [13, 15]. However, the MSRAction-3D dataset is too small to bring significant improvement." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 496, + 287, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 496, + 287, + 604 + ], + "spans": [ + { + "bbox": [ + 46, + 496, + 287, + 604 + ], + "type": "text", + "content": "NTU-RGBD. The setup of fine-tuning is the same as pre-training, except that the pre-trained model is fine-tuned for 20 epochs with a batch size of 48 on 8 GPUs and the initial learning rate is set to 0.0005. From the end-to-end fine-tuning in Table 2, we can see that our pre-training method introduces an accuracy improvement compared with the baseline. By predicting the spatio-temporal structure, our MaST-Pre learns appearance and motion information during pre-training." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 611, + 192, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 611, + 192, + 624 + ], + "spans": [ + { + "bbox": [ + 47, + 611, + 192, + 624 + ], + "type": "text", + "content": "4.4. Semi-supervised Learning" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "content": "We also evaluate the learned representations using a semi-supervised learning experiment. Specifically, the cross-subject training set of NTU-RGBD is used for pretraining, and then only a " + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 46, + 629, + 287, + 713 + ], + "type": "text", + "content": " training set is used for finetuning in a supervised manner. The setup of our semi-supervised learning experiment is the same as end-to-end fine-tuning on NTU-RGBD (Sec. 4.3)." + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 307, + 91, + 545, + 208 + ], + "blocks": [ + { + "bbox": [ + 306, + 69, + 545, + 90 + ], + "lines": [ + { + "bbox": [ + 306, + 69, + 545, + 90 + ], + "spans": [ + { + "bbox": [ + 306, + 69, + 545, + 90 + ], + "type": "text", + "content": "Table 3. Gesture recognition accuracy (\\%) on NvGesture (NvG) and SHREC'17 (SHR)." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 307, + 91, + 545, + 208 + ], + "lines": [ + { + "bbox": [ + 307, + 91, + 545, + 208 + ], + "spans": [ + { + "bbox": [ + 307, + 91, + 545, + 208 + ], + "type": "table", + "html": "
MethodsNvGSHR
FlickerNet [26]86.3-
PLSTM [27]85.987.6
PLSTM-PSS [27]87.393.1
Kinet [50]89.195.2
P4Transformer [9] (30 Epochs)84.887.5
P4Transformer [9] (50 Epochs)87.791.2
P4Transformer + MaST-Pre (30 Epochs)87.690.2
P4Transformer + MaST-Pre (50 Epochs)89.392.4
", + "image_path": "4119c9b3a749d6521f5e57b7cd5750c0c6a8147f9497e3765f19aae924de9410.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 228, + 545, + 289 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 228, + 545, + 289 + ], + "spans": [ + { + "bbox": [ + 305, + 228, + 545, + 289 + ], + "type": "text", + "content": "From Table 2, we can see that the " + }, + { + "bbox": [ + 305, + 228, + 545, + 289 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 305, + 228, + 545, + 289 + ], + "type": "text", + "content": " semi-supervised result produced by our MaST-Pre achieves comparable performance to the fully supervised baseline even with only limited annotated data. This clearly demonstrates that MaST-Pre learns high-quality representations." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 296, + 415, + 308 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 296, + 415, + 308 + ], + "spans": [ + { + "bbox": [ + 306, + 296, + 415, + 308 + ], + "type": "text", + "content": "4.5. Transfer Learning" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 315, + 545, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 315, + 545, + 434 + ], + "spans": [ + { + "bbox": [ + 304, + 315, + 545, + 434 + ], + "type": "text", + "content": "To evaluate the generalization ability of the representations learned by MaST-Pre, we conduct experiments by transferring the pre-trained encoder to other datasets. Specifically, the encoder is first pre-trained on NTU-RGBD following the setup in Sec. 4.2, and then fine-tuned with a new classifier on NvGesture and SHREC'17, respectively. Our transfer experiments are not only cross-dataset but also cross-task, i.e., from action recognition to gesture recognition. We compare our fine-tuned results to the fully supervised baseline in Table 3." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 435, + 545, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 435, + 545, + 602 + ], + "spans": [ + { + "bbox": [ + 304, + 435, + 545, + 602 + ], + "type": "text", + "content": "During fine-tuning, an AdamW optimizer with a batch size of 24 is used, and the initial learning rate is set to 0.002 with a cosine decay strategy. The pre-trained model is fine-tuned for 50 epochs on NvGesture and SHREC'17. As shown in Table 3, our MaST-Pre pre-training facilitates the P4Transformer to produce superior accuracy compared to the fully supervised baseline. Moreover, our MaST-Pre also performs faster convergence. Compared with the baseline without pre-training, significant improvements are achieved after fine-tuning for only 30 epochs (e.g., " + }, + { + "bbox": [ + 304, + 435, + 545, + 602 + ], + "type": "inline_equation", + "content": "84.8\\% \\rightarrow 87.6\\%" + }, + { + "bbox": [ + 304, + 435, + 545, + 602 + ], + "type": "text", + "content": " on NvGesture and " + }, + { + "bbox": [ + 304, + 435, + 545, + 602 + ], + "type": "inline_equation", + "content": "87.5\\% \\rightarrow 90.2\\%" + }, + { + "bbox": [ + 304, + 435, + 545, + 602 + ], + "type": "text", + "content": " on SHREC'17). This demonstrates that our MaST-Pre has excellent generalization ability across different tasks, facilitating the accuracy improvement of downstream tasks." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 610, + 406, + 622 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 610, + 406, + 622 + ], + "spans": [ + { + "bbox": [ + 306, + 610, + 406, + 622 + ], + "type": "text", + "content": "4.6. Ablation Studies" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 629, + 545, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 629, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 305, + 629, + 545, + 677 + ], + "type": "text", + "content": "In order to balance authority and efficiency, the experiments of ablation studies are conducted on " + }, + { + "bbox": [ + 305, + 629, + 545, + 677 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 305, + 629, + 545, + 677 + ], + "type": "text", + "content": " NTU-RGBD, which contains 4032 training videos and 1656 test videos with category balance." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 677, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 712 + ], + "type": "text", + "content": "Architecture Design. Our MaST-Pre utilizes a two-stream prediction to jointly learn both appearance and motion information. To demonstrate the effectiveness of this" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16585" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 56, + 68, + 288, + 350 + ], + "blocks": [ + { + "bbox": [ + 56, + 68, + 288, + 350 + ], + "lines": [ + { + "bbox": [ + 56, + 68, + 288, + 350 + ], + "spans": [ + { + "bbox": [ + 56, + 68, + 288, + 350 + ], + "type": "image", + "image_path": "9528bb91f590fd312dfdf100d83b75bff3863b40d801f734f3c09766605af0c0.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 352, + 547, + 373 + ], + "lines": [ + { + "bbox": [ + 46, + 352, + 547, + 373 + ], + "spans": [ + { + "bbox": [ + 46, + 352, + 547, + 373 + ], + "type": "text", + "content": "Figure 4. Visualization of reconstruction results. For each action sample, the ground truth lies in the first row, the masked video lies in the second row, and the result lies in the third row." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 294, + 68, + 522, + 350 + ], + "blocks": [ + { + "bbox": [ + 294, + 68, + 522, + 350 + ], + "lines": [ + { + "bbox": [ + 294, + 68, + 522, + 350 + ], + "spans": [ + { + "bbox": [ + 294, + 68, + 522, + 350 + ], + "type": "image", + "image_path": "1148d5257b196bd26e29b7ac0286ca37566e3d11fd510131040ecc8b0dc302c2.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 523, + 70, + 533, + 350 + ], + "lines": [ + { + "bbox": [ + 523, + 70, + 533, + 350 + ], + "spans": [ + { + "bbox": [ + 523, + 70, + 533, + 350 + ], + "type": "text", + "content": "Rnne aenrnnnne nnnnne ennnnne eannnne" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_footnote" + } + ], + "index": 1 + }, + { + "type": "table", + "bbox": [ + 48, + 401, + 287, + 457 + ], + "blocks": [ + { + "bbox": [ + 67, + 390, + 266, + 401 + ], + "lines": [ + { + "bbox": [ + 67, + 390, + 266, + 401 + ], + "spans": [ + { + "bbox": [ + 67, + 390, + 266, + 401 + ], + "type": "text", + "content": "Table 4. Ablation studies on pre-training architectures." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 401, + 287, + 457 + ], + "lines": [ + { + "bbox": [ + 48, + 401, + 287, + 457 + ], + "spans": [ + { + "bbox": [ + 48, + 401, + 287, + 457 + ], + "type": "table", + "html": "
Appearance StreamMotion StreamAcc. (%)
A065.85
A1✓70.13
A2 (Ours)✓✓78.25
", + "image_path": "6379ecd2e53538ddfb89eb5c655662a897ddfedea0c77f885fa2119d8d1e5061.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 48, + 479, + 285, + 524 + ], + "blocks": [ + { + "bbox": [ + 86, + 468, + 247, + 479 + ], + "lines": [ + { + "bbox": [ + 86, + 468, + 247, + 479 + ], + "spans": [ + { + "bbox": [ + 86, + 468, + 247, + 479 + ], + "type": "text", + "content": "Table 5. Ablation studies on masking ratios." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 479, + 285, + 524 + ], + "lines": [ + { + "bbox": [ + 48, + 479, + 285, + 524 + ], + "spans": [ + { + "bbox": [ + 48, + 479, + 285, + 524 + ], + "type": "table", + "html": "
B1B2 (Ours)B3
Masking Ratio65%75%85%
Accuracy (%)76.9178.2577.20
", + "image_path": "86069651966d97d4db0c809ed5fa240aa87c87e81a1df3a0a7f470cd3e97d20b.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 545, + 287, + 688 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 545, + 287, + 688 + ], + "spans": [ + { + "bbox": [ + 46, + 545, + 287, + 688 + ], + "type": "text", + "content": "architecture, we first present the performance of model A0 as the " + }, + { + "bbox": [ + 46, + 545, + 287, + 688 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 46, + 545, + 287, + 688 + ], + "type": "text", + "content": " NTU-RGBD baseline in a fully supervised manner " + }, + { + "bbox": [ + 46, + 545, + 287, + 688 + ], + "type": "inline_equation", + "content": "(65.85\\%)" + }, + { + "bbox": [ + 46, + 545, + 287, + 688 + ], + "type": "text", + "content": ". Then, model A1 is developed by removing the motion prediction stream. Quantitative results are presented in Table 4. It shows that with solely the appearance stream, the performance gain introduced by model A1 pretraining is limited. When these two streams are combined, comprehensive information can be learned and superior accuracy is achieved by our model A2 " + }, + { + "bbox": [ + 46, + 545, + 287, + 688 + ], + "type": "inline_equation", + "content": "(65.85\\% \\rightarrow 78.25\\%)" + }, + { + "bbox": [ + 46, + 545, + 287, + 688 + ], + "type": "text", + "content": ". This demonstrates the effectiveness of our mask-based pretraining on point cloud videos and the necessity of the task of explicitly predicting motions." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 689, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 689, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 689, + 287, + 713 + ], + "type": "text", + "content": "Masking Ratio. The masking operation plays a critical role in our MaST-Pre. Therefore, we conduct experiments" + } + ] + } + ], + "index": 9 + }, + { + "type": "table", + "bbox": [ + 307, + 401, + 543, + 462 + ], + "blocks": [ + { + "bbox": [ + 331, + 390, + 518, + 401 + ], + "lines": [ + { + "bbox": [ + 331, + 390, + 518, + 401 + ], + "spans": [ + { + "bbox": [ + 331, + 390, + 518, + 401 + ], + "type": "text", + "content": "Table 6. Ablation studies on the appearance stream." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 307, + 401, + 543, + 462 + ], + "lines": [ + { + "bbox": [ + 307, + 401, + 543, + 462 + ], + "spans": [ + { + "bbox": [ + 307, + 401, + 543, + 462 + ], + "type": "table", + "html": "
# FramesTemporal & SpatialAccuracy (%)
D11-77.34
D23Coupling58.60
D3 (Ours)3Decoupling78.25
", + "image_path": "de1293a0174bf77d428a350fc5b62491c9fa7b767324c56449cf9e0d84ebb734.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 484, + 545, + 532 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 484, + 545, + 532 + ], + "spans": [ + { + "bbox": [ + 304, + 484, + 545, + 532 + ], + "type": "text", + "content": "to study different masking ratios, and the results are presented in Table 5. It shows that a high masking ratio is beneficial to our MaST-Pre and the highest accuracy is achieved at " + }, + { + "bbox": [ + 304, + 484, + 545, + 532 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 304, + 484, + 545, + 532 + ], + "type": "text", + "content": " masking ratio (model B2)." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 533, + 546, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 546, + 640 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 546, + 640 + ], + "type": "text", + "content": "Appearance Stream. Right reconstruction targets in the appearance stream contribute to the performance of our MaST-Pre. For model D3, in each point tube, the reconstruction loss (Eq. 2) is first calculated in each frame separately and then aggregated over " + }, + { + "bbox": [ + 304, + 533, + 546, + 640 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 304, + 533, + 546, + 640 + ], + "type": "text", + "content": " frames, which is a decoupled manner. In contrast, model D2 calculates the reconstruction loss in a coupled manner by considering all points together. We also develop model D1 to reconstruct only the middle frame of each point tube." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 642, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 547, + 713 + ], + "type": "text", + "content": "As shown in Table 6, model D2 brings no accuracy gain and is even worse than the baseline model A0 (58.60% vs. 65.85%). In addition, D3 outperforms D1 and D2. This is because D3 implicitly learns spatio-temporal information during the process of reconstructing decoupled point tubes. We further visualize the reconstruction results in Fig. 4." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "16586" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 61, + 71, + 215, + 221 + ], + "blocks": [ + { + "bbox": [ + 61, + 71, + 215, + 221 + ], + "lines": [ + { + "bbox": [ + 61, + 71, + 215, + 221 + ], + "spans": [ + { + "bbox": [ + 61, + 71, + 215, + 221 + ], + "type": "image", + "image_path": "1dc66e7b855c05ca16fddd4bb1ec50c13c11297491aa996f499b40007da396a3.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 61, + 224, + 86, + 236 + ], + "blocks": [ + { + "bbox": [ + 61, + 224, + 86, + 236 + ], + "lines": [ + { + "bbox": [ + 61, + 224, + 86, + 236 + ], + "spans": [ + { + "bbox": [ + 61, + 224, + 86, + 236 + ], + "type": "image", + "image_path": "e7150fb7486695d9870fe7efc64d989efa51cfde878394dbc3a2a08efb0a10c0.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 61, + 242, + 530, + 254 + ], + "lines": [ + { + "bbox": [ + 61, + 242, + 530, + 254 + ], + "spans": [ + { + "bbox": [ + 61, + 242, + 530, + 254 + ], + "type": "text", + "content": "Figure 5. Samples of temporal cardinality difference, computed by subtracting cardinality histograms of frame " + }, + { + "bbox": [ + 61, + 242, + 530, + 254 + ], + "type": "inline_equation", + "content": "t - 1" + }, + { + "bbox": [ + 61, + 242, + 530, + 254 + ], + "type": "text", + "content": " from frame " + }, + { + "bbox": [ + 61, + 242, + 530, + 254 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 61, + 242, + 530, + 254 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "bbox": [ + 87, + 226, + 121, + 234 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 87, + 226, + 121, + 234 + ], + "spans": [ + { + "bbox": [ + 87, + 226, + 121, + 234 + ], + "type": "text", + "content": "Frame t-1" + } + ] + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 131, + 224, + 150, + 236 + ], + "blocks": [ + { + "bbox": [ + 131, + 224, + 150, + 236 + ], + "lines": [ + { + "bbox": [ + 131, + 224, + 150, + 236 + ], + "spans": [ + { + "bbox": [ + 131, + 224, + 150, + 236 + ], + "type": "image", + "image_path": "8c5d604dc5668e452de5a32e3f60b58970772c66f04550cd887059df5e0ddf5d.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "bbox": [ + 154, + 227, + 181, + 234 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 154, + 227, + 181, + 234 + ], + "spans": [ + { + "bbox": [ + 154, + 227, + 181, + 234 + ], + "type": "text", + "content": "Frame " + }, + { + "bbox": [ + 154, + 227, + 181, + 234 + ], + "type": "inline_equation", + "content": "t" + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 193, + 227, + 214, + 236 + ], + "blocks": [ + { + "bbox": [ + 193, + 227, + 214, + 236 + ], + "lines": [ + { + "bbox": [ + 193, + 227, + 214, + 236 + ], + "spans": [ + { + "bbox": [ + 193, + 227, + 214, + 236 + ], + "type": "image", + "image_path": "62d965fd48f312bb9a034fc9fdce71491efc0c1bd33ba73bbbaebf1fb1305fd6.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "bbox": [ + 216, + 228, + 254, + 235 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 216, + 228, + 254, + 235 + ], + "spans": [ + { + "bbox": [ + 216, + 228, + 254, + 235 + ], + "type": "text", + "content": "Movement" + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 247, + 72, + 376, + 206 + ], + "blocks": [ + { + "bbox": [ + 247, + 72, + 376, + 206 + ], + "lines": [ + { + "bbox": [ + 247, + 72, + 376, + 206 + ], + "spans": [ + { + "bbox": [ + 247, + 72, + 376, + 206 + ], + "type": "image", + "image_path": "b22d679be37653c6d254f32dcef9740ae31264fc409eecf7f701923503850eea.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 273, + 209, + 356, + 217 + ], + "lines": [ + { + "bbox": [ + 273, + 209, + 356, + 217 + ], + "spans": [ + { + "bbox": [ + 273, + 209, + 356, + 217 + ], + "type": "text", + "content": "(b) Putting Hands Down" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 264, + 226, + 305, + 235 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 264, + 226, + 305, + 235 + ], + "spans": [ + { + "bbox": [ + 264, + 226, + 305, + 235 + ], + "type": "text", + "content": "Key Point" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 328, + 226, + 385, + 235 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 328, + 226, + 385, + 235 + ], + "spans": [ + { + "bbox": [ + 328, + 226, + 385, + 235 + ], + "type": "text", + "content": "Support Domain" + } + ] + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 392, + 73, + 535, + 205 + ], + "blocks": [ + { + "bbox": [ + 392, + 73, + 535, + 205 + ], + "lines": [ + { + "bbox": [ + 392, + 73, + 535, + 205 + ], + "spans": [ + { + "bbox": [ + 392, + 73, + 535, + 205 + ], + "type": "image", + "image_path": "057e03f0ae59c4725d190ae9cd8f4dc530050dcae4605c7be33a3574e2ee23a2.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 439, + 209, + 504, + 218 + ], + "lines": [ + { + "bbox": [ + 439, + 209, + 504, + 218 + ], + "spans": [ + { + "bbox": [ + 439, + 209, + 504, + 218 + ], + "type": "text", + "content": "(c) Kicking Forward" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 394, + 222, + 533, + 239 + ], + "blocks": [ + { + "bbox": [ + 394, + 222, + 533, + 239 + ], + "lines": [ + { + "bbox": [ + 394, + 222, + 533, + 239 + ], + "spans": [ + { + "bbox": [ + 394, + 222, + 533, + 239 + ], + "type": "image", + "image_path": "28a411feced4c81fa9bb4bf3148c3ccf3b7bbdafd39aba34a2114c4b8853afae.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + } + ], + "index": 13 + }, + { + "type": "table", + "bbox": [ + 53, + 273, + 225, + 318 + ], + "blocks": [ + { + "bbox": [ + 179, + 262, + 412, + 273 + ], + "lines": [ + { + "bbox": [ + 179, + 262, + 412, + 273 + ], + "spans": [ + { + "bbox": [ + 179, + 262, + 412, + 273 + ], + "type": "text", + "content": "Table 7. Ablation studies on the temporal cardinality difference." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 53, + 273, + 225, + 318 + ], + "lines": [ + { + "bbox": [ + 53, + 273, + 225, + 318 + ], + "spans": [ + { + "bbox": [ + 53, + 273, + 225, + 318 + ], + "type": "table", + "html": "
E1E2 (Ours)E3
# Section4816
Accuracy (%)77.8578.2569.50
", + "image_path": "b9294ae5bc2021484ebcd535153f41a2a34ae896564027980534ba309281114d.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "table_body" + } + ], + "index": 16 + }, + { + "type": "table", + "bbox": [ + 236, + 274, + 377, + 318 + ], + "blocks": [ + { + "bbox": [ + 236, + 274, + 377, + 318 + ], + "lines": [ + { + "bbox": [ + 236, + 274, + 377, + 318 + ], + "spans": [ + { + "bbox": [ + 236, + 274, + 377, + 318 + ], + "type": "table", + "html": "
F1F2 (Ours)
InterpolationX✓
Accuracy (%)76.6978.25
", + "image_path": "06b3d46cad289275d4bd66e8f1bd4ae27d88ee85b2ce2e514a99c9d3e4ab68a2.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "table_body" + } + ], + "index": 17 + }, + { + "type": "table", + "bbox": [ + 388, + 274, + 531, + 318 + ], + "blocks": [ + { + "bbox": [ + 388, + 274, + 531, + 318 + ], + "lines": [ + { + "bbox": [ + 388, + 274, + 531, + 318 + ], + "spans": [ + { + "bbox": [ + 388, + 274, + 531, + 318 + ], + "type": "table", + "html": "
G1 (Ours)G2
# Stride12
Accuracy (%)78.2575.85
", + "image_path": "920ba76df114a5871eb8ba03a448c9ba984c8043e40181f4b64e619e5eb4ef10.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "table_body" + } + ], + "index": 18 + }, + { + "bbox": [ + 46, + 338, + 287, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 338, + 287, + 434 + ], + "spans": [ + { + "bbox": [ + 46, + 338, + 287, + 434 + ], + "type": "text", + "content": "Temporal Cardinality Difference. In order to investigate the temporal cardinality difference, we present the results under different sections, interpolations, and strides in Table 7. We develop the model E1/E3 to divide the support domain into 4/16 sections, while their accuracy is lower than E2 with 8 sections. This is because small space resolution will introduce noises and large resolution makes temporal cardinality difference insensitive to motions." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 46, + 435, + 287, + 508 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 435, + 287, + 508 + ], + "spans": [ + { + "bbox": [ + 46, + 435, + 287, + 508 + ], + "type": "text", + "content": "Next, we develop model F1 by removing interpolation. While F2 outperforms F1 because interpolation improves its robustness. Finally, we develop model G2 to calculate the cardinality difference with temporal stride 2, but its performance is worse than G1 with stride 1. This is because a large temporal stride cannot capture fine-grained motions." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 46, + 509, + 287, + 664 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 509, + 287, + 664 + ], + "spans": [ + { + "bbox": [ + 46, + 509, + 287, + 664 + ], + "type": "text", + "content": "We further visualize multiple samples of temporal cardinality difference in Fig. 5 to demonstrate its effectiveness in modeling motions. We present three typical actions, each consisting of two samples. As shown in Fig. 5(a), the temporal cardinality differences of the two raising hands actions project extremely similar motion patterns. Points in the first and seventh octants flow out heavily over time. Meanwhile, temporal cardinality differences within putting hands down (Fig. 5(b)) also display similarities, as well as in kicking forward (Fig. 5(c)). In particular, the temporal cardinality differences between raising hands and putting hands down are approximately reversible, which reflects its effectiveness in modeling dynamics." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "type": "text", + "content": "Computational Complexity. Table 8 shows the pretraining complexity and corresponding fine-tuning accuracy of the two models. After adding the motion prediction stream, model H2 achieves much higher accuracy than" + } + ] + } + ], + "index": 22 + }, + { + "type": "table", + "bbox": [ + 307, + 346, + 544, + 392 + ], + "blocks": [ + { + "bbox": [ + 306, + 336, + 529, + 346 + ], + "lines": [ + { + "bbox": [ + 306, + 336, + 529, + 346 + ], + "spans": [ + { + "bbox": [ + 306, + 336, + 529, + 346 + ], + "type": "text", + "content": "Table 8. Time (mins/epoch) and memory (MiB) complexities." + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 307, + 346, + 544, + 392 + ], + "lines": [ + { + "bbox": [ + 307, + 346, + 544, + 392 + ], + "spans": [ + { + "bbox": [ + 307, + 346, + 544, + 392 + ], + "type": "table", + "html": "
ArchitecturesEncoderTimeMemoryAcc. (%)
H1Only Appearancew/o [M]5.4641470.13
H2 (Ours)Two Streamsw/o [M]6.2641878.25
", + "image_path": "ee71fe7f13f5ec83809ff58578a43de341de4a204b0834d0e93850ea5f9610eb.jpg" + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "table_body" + } + ], + "index": 24 + }, + { + "bbox": [ + 305, + 414, + 545, + 437 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 414, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 305, + 414, + 545, + 437 + ], + "type": "text", + "content": "H1 with only a minor increase in pre-training complexities " + }, + { + "bbox": [ + 305, + 414, + 545, + 437 + ], + "type": "inline_equation", + "content": "(70.13\\% \\rightarrow 78.25\\%)" + }, + { + "bbox": [ + 305, + 414, + 545, + 437 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 306, + 452, + 378, + 464 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 452, + 378, + 464 + ], + "spans": [ + { + "bbox": [ + 306, + 452, + 378, + 464 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 304, + 473, + 545, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 473, + 545, + 605 + ], + "spans": [ + { + "bbox": [ + 304, + 473, + 545, + 605 + ], + "type": "text", + "content": "In this paper, we introduce a masked spatio-temporal structure prediction method for point cloud video pretraining, termed as MaST-Pre. For modeling subtle dynamics, the temporal cardinality difference is proposed, which can be calculated online directly from inputs. Based on point-tube masking, MaST-Pre jointly conducts point cloud video reconstruction and temporal cardinality difference prediction to learn both appearance and motion information. Experiments on four benchmarks show that our MaST-Pre is an effective pre-training framework to boost the performance of point cloud video understanding." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 304, + 605, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 545, + 714 + ], + "type": "text", + "content": "Acknowledgments. This work was partially supported by the Fundamental Research Funds for the Central Universities (No. 226-2023-00048), the National Natural Science Foundation of China (No. U20A20185, 61972435), the Guangdong Basic and Applied Basic Research Foundation (2022B1515020103), the Shenzhen Science and Technology Program (No. RCYX20200714114641140), and the Chongqing Technology Innovation and Application Development Special Key Project(cstc2021jscx-cylhX0006)." + } + ] + } + ], + "index": 28 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16587" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 286, + 712 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 53, + 91, + 286, + 123 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 286, + 123 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 286, + 123 + ], + "type": "text", + "content": "[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lučić, and Cordelia Schmid. Vivit: A video vision transformer. In ICCV, 2021. 4" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 124, + 286, + 147 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 124, + 286, + 147 + ], + "spans": [ + { + "bbox": [ + 53, + 124, + 286, + 147 + ], + "type": "text", + "content": "[2] Hangbo Bao, Li Dong, Songhao Piao, and Furu Wei. BEiT: BERT pre-training of image transformers. In ICLR, 2022. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 148, + 286, + 255 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 148, + 286, + 255 + ], + "spans": [ + { + "bbox": [ + 53, + 148, + 286, + 255 + ], + "type": "text", + "content": "[3] Tom Brown, Benjamin Mann, Nick Ryder, Melanie Subbiah, Jared D Kaplan, Prafulla Dhariwal, Arvind Neelakantan, Pranav Shyam, Girish Sastry, Amanda Askell, Sandhini Agarwal, Ariel Herbert-Voss, Gretchen Krueger, Tom Henighan, Rewon Child, Aditya Ramesh, Daniel Ziegler, Jeffrey Wu, Clemens Winter, Chris Hesse, Mark Chen, Eric Sigler, Mateusz Litwin, Scott Gray, Benjamin Chess, Jack Clark, Christopher Berner, Sam McCandlish, Alec Radford, Ilya Sutskever, and Dario Amodei. Language models are few-shot learners. In NeurIPS, 2020. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 257, + 286, + 290 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 257, + 286, + 290 + ], + "spans": [ + { + "bbox": [ + 53, + 257, + 286, + 290 + ], + "type": "text", + "content": "[4] Mark Chen, Alec Radford, Rewon Child, Jeffrey Wu, Heewoo Jun, David Luan, and Ilya Sutskever. Generative pretraining from pixels. In ICML, 2020. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 291, + 286, + 323 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 291, + 286, + 323 + ], + "spans": [ + { + "bbox": [ + 53, + 291, + 286, + 323 + ], + "type": "text", + "content": "[5] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning of visual representations. In ICML, 2020. 1" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 324, + 286, + 356 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 324, + 286, + 356 + ], + "spans": [ + { + "bbox": [ + 53, + 324, + 286, + 356 + ], + "type": "text", + "content": "[6] Christopher Choy, JunYoung Gwak, and Silvio Savarese. 4D spatio-temporal convnets: Minkowski convolutional neural networks. In CVPR, 2019. 1" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 357, + 286, + 401 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 357, + 286, + 401 + ], + "spans": [ + { + "bbox": [ + 53, + 357, + 286, + 401 + ], + "type": "text", + "content": "[7] Quentin De Smedt, Hazem Wannous, Jean-Philippe Vandeborre, Joris Guerry, Bertrand Le Saux, and David Filiat. SHREC'17 Track: 3D hand gesture recognition using a depth and skeletal dataset. In 3DOR, 2017. 5" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 403, + 286, + 467 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 403, + 286, + 467 + ], + "spans": [ + { + "bbox": [ + 53, + 403, + 286, + 467 + ], + "type": "text", + "content": "[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In ICLR, 2021. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 468, + 286, + 501 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 468, + 286, + 501 + ], + "spans": [ + { + "bbox": [ + 53, + 468, + 286, + 501 + ], + "type": "text", + "content": "[9] Hehe Fan, Yi Yang, and Mohan Kankanhalli. Point 4D transformer networks for spatio-temporal modeling in point cloud videos. In CVPR, 2021. 1, 2, 3, 4, 5, 6" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 502, + 286, + 545 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 502, + 286, + 545 + ], + "spans": [ + { + "bbox": [ + 48, + 502, + 286, + 545 + ], + "type": "text", + "content": "[10] Hehe Fan, Yi Yang, and Mohan Kankanhalli. Point spatiotemporal transformer networks for point cloud video modeling. IEEE Transactions on Pattern Analysis and Machine Intelligence, 45(2):2181-2192, 2022. 1, 3, 5, 6" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 546, + 286, + 579 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 546, + 286, + 579 + ], + "spans": [ + { + "bbox": [ + 48, + 546, + 286, + 579 + ], + "type": "text", + "content": "[11] Hehe Fan, Xin Yu, Yuhang Ding, Yi Yang, and Mohan Kankanhalli. PSTNet: Point spatio-temporal convolution on point cloud sequences. In ICLR, 2021. 1, 2, 3, 5, 6" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 580, + 286, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 580, + 286, + 634 + ], + "spans": [ + { + "bbox": [ + 48, + 580, + 286, + 634 + ], + "type": "text", + "content": "[12] Hehe Fan, Xin Yu, Yi Yang, and Mohan Kankanhalli. Deep hierarchical representation of point cloud videos via spatio-temporal decomposition. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(12):9918-9930, 2021. 1, 3, 5, 6" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 635, + 286, + 667 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 635, + 286, + 667 + ], + "spans": [ + { + "bbox": [ + 48, + 635, + 286, + 667 + ], + "type": "text", + "content": "[13] Christoph Feichtenhofer, Haoqi Fan, Yanghao Li, and Kaiming He. Masked autoencoders as spatiotemporal learners. NeurIPS, 2022. 2, 4, 5, 6" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 669, + 286, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 669, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 669, + 286, + 712 + ], + "type": "text", + "content": "[14] Basura Fernando, Efstratios Gavves, José Oramas, Amir Ghodrati, and Tinne Tuytelaars. Rank pooling for action recognition. IEEE transactions on pattern analysis and machine intelligence, 39(4):773-787, 2016. 3" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 34, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "text", + "content": "[15] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dollár, and Ross Girshick. Masked autoencoders are scalable vision learners. In CVPR, 2022. 1, 2, 4, 5, 6" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 107, + 545, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 140 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 140 + ], + "type": "text", + "content": "[16] Kaiming He, Haoqi Fan, Yuxin Wu, Saining Xie, and Ross Girshick. Momentum contrast for unsupervised visual representation learning. In CVPR, 2020. 1" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 141, + 545, + 174 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 141, + 545, + 174 + ], + "spans": [ + { + "bbox": [ + 307, + 141, + 545, + 174 + ], + "type": "text", + "content": "[17] Ji Hou, Benjamin Graham, Matthias Nießner, and Saining Xie. Exploring data-efficient 3D scene understanding with contrastive scene contexts. In CVPR, 2021. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 176, + 545, + 209 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 176, + 545, + 209 + ], + "spans": [ + { + "bbox": [ + 307, + 176, + 545, + 209 + ], + "type": "text", + "content": "[18] Siyuan Huang, Yichen Xie, Song-Chun Zhu, and Yixin Zhu. Spatio-temporal self-supervised representation learning for 3D point clouds. In ICCV, 2021. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 210, + 545, + 253 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 210, + 545, + 253 + ], + "spans": [ + { + "bbox": [ + 307, + 210, + 545, + 253 + ], + "type": "text", + "content": "[19] Jacob Devlin Ming-Wei Chang Kenton and Lee Kristina Toutanova. BERT: Pre-training of deep bidirectional transformers for language understanding. In NAACL, 2019. 1, 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 255, + 545, + 288 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 255, + 545, + 288 + ], + "spans": [ + { + "bbox": [ + 307, + 255, + 545, + 288 + ], + "type": "text", + "content": "[20] Wanqing Li, Zhengyou Zhang, and Zicheng Liu. Action recognition based on a bag of 3D points. In CVPRW, 2010. 5" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 290, + 545, + 334 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 290, + 545, + 334 + ], + "spans": [ + { + "bbox": [ + 307, + 290, + 545, + 334 + ], + "type": "text", + "content": "[21] Hanxue Liang, Hehe Fan, Zhiwen Fan, Yi Wang, Tianlong Chen, Yu Cheng, and Zhangyang Wang. Point cloud domain adaptation via masked local 3D structure prediction. In ECCV, 2022. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 335, + 545, + 368 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 335, + 545, + 368 + ], + "spans": [ + { + "bbox": [ + 307, + 335, + 545, + 368 + ], + "type": "text", + "content": "[22] Haotian Liu, Mu Cai, and Yong Jae Lee. Masked discrimination for self-supervised learning on point clouds. In ECCV, 2022. 2" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 370, + 545, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 370, + 545, + 403 + ], + "spans": [ + { + "bbox": [ + 307, + 370, + 545, + 403 + ], + "type": "text", + "content": "[23] Xingyu Liu, Charles R Qi, and Leonidas J Guibas. Flownet3D: Learning scene flow in 3D point clouds. In CVPR, 2019. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 404, + 545, + 437 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 404, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 307, + 404, + 545, + 437 + ], + "type": "text", + "content": "[24] Xingyu Liu, Mengyuan Yan, and Jeannette Bohg. MeteorNet: Deep learning on dynamic 3D point cloud sequences. In ICCV, 2019. 1, 3, 5" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 438, + 545, + 471 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 438, + 545, + 471 + ], + "spans": [ + { + "bbox": [ + 307, + 438, + 545, + 471 + ], + "type": "text", + "content": "[25] Ze Liu, Jia Ning, Yue Cao, Yixuan Wei, Zheng Zhang, Stephen Lin, and Han Hu. Video swim transformer. In CVPR, 2022. 4" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 473, + 545, + 506 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 473, + 545, + 506 + ], + "spans": [ + { + "bbox": [ + 307, + 473, + 545, + 506 + ], + "type": "text", + "content": "[26] Yuecong Min, Xiujuan Chai, Lei Zhao, and Xilin Chen. FlickerNet: Adaptive 3D gesture recognition from sparse point clouds. In BMVC, 2019. 6" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 508, + 545, + 540 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 508, + 545, + 540 + ], + "spans": [ + { + "bbox": [ + 307, + 508, + 545, + 540 + ], + "type": "text", + "content": "[27] Yuecong Min, Yanxiao Zhang, Xiujuan Chai, and Xin Chen. An efficient PointLSTM for point clouds based gesture recognition. In CVPR, 2020. 5, 6" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 543, + 545, + 586 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 543, + 545, + 586 + ], + "spans": [ + { + "bbox": [ + 307, + 543, + 545, + 586 + ], + "type": "text", + "content": "[28] Pavlo Molchanov, Xiaodong Yang, Shalini Gupta, Kihwan Kim, Stephen Tyree, and Jan Kautz. Online detection and classification of dynamic hand gestures with recurrent 3D convolutional neural network. In CVPR, 2016. 5" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 587, + 545, + 620 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 587, + 545, + 620 + ], + "spans": [ + { + "bbox": [ + 307, + 587, + 545, + 620 + ], + "type": "text", + "content": "[29] Yatian Pang, Wenxiao Wang, Francis E.H. Tay, Wei Liu, Yonghong Tian, and Li Yuan. Masked autoencoders for point cloud self-supervised learning. In ECCV, 2022. 2, 3" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 307, + 622, + 545, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 622, + 545, + 644 + ], + "spans": [ + { + "bbox": [ + 307, + 622, + 545, + 644 + ], + "type": "text", + "content": "[30] Helmut Pottmann and Johannes Wallner. Computational line geometry. Springer, 2001. 3" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 307, + 646, + 545, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 646, + 545, + 678 + ], + "spans": [ + { + "bbox": [ + 307, + 646, + 545, + 678 + ], + "type": "text", + "content": "[31] Rui Qian, Shuangrui Ding, Xian Liu, and Dahua Lin. Static and dynamic concepts for self-supervised video representation learning. In ECCV, 2022. 4" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 307, + 680, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 680, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 680, + 545, + 712 + ], + "type": "text", + "content": "[32] Yongming Rao, Jiwen Lu, and Jie Zhou. Global-local bidirectional reasoning for unsupervised representation learning of 3D point clouds. In CVPR, 2020. 2" + } + ] + } + ], + "index": 33 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "16588" + } + ] + } + ], + "index": 35 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "type": "text", + "content": "[33] Amir Shahroudy, Jun Liu, Tian-Tsong Ng, and Gang Wang. NTU RGB+D: A large scale dataset for 3D human activity analysis. In CVPR, 2016. 5" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 287, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 287, + 150 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 287, + 150 + ], + "type": "text", + "content": "[34] Zhiqiang Shen, Xiaoxiao Sheng, Longguang Wang, Yulan Guo, Qiong Liu, and Xi Zhou. Pointemp: Contrastive mask prediction for self-supervised learning on point cloud videos. In CVPR, 2023. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 152, + 287, + 185 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 152, + 287, + 185 + ], + "spans": [ + { + "bbox": [ + 48, + 152, + 287, + 185 + ], + "type": "text", + "content": "[35] Xiaoxiao Sheng, Zhiqiang Shen, and Gang Xiao. Contrastive predictive autoencoders for dynamic point cloud self-supervised learning. In AAAI, 2023. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 186, + 287, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 186, + 287, + 217 + ], + "spans": [ + { + "bbox": [ + 48, + 186, + 287, + 217 + ], + "type": "text", + "content": "[36] Karen Simonyan and Andrew Zisserman. Two-stream convolutional networks for action recognition in videos. In NeurIPS, 2014. 4" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 220, + 287, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 220, + 287, + 262 + ], + "spans": [ + { + "bbox": [ + 48, + 220, + 287, + 262 + ], + "type": "text", + "content": "[37] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. VideoMAE: Masked autoencoders are data-efficient learners for self-supervised video pre-training. In NeurIPS, 2022. 2, 4, 5" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 264, + 287, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 264, + 287, + 308 + ], + "spans": [ + { + "bbox": [ + 48, + 264, + 287, + 308 + ], + "type": "text", + "content": "[38] Haiyan Wang, Liang Yang, Xuejian Rong, Jinglun Feng, and Yingli Tian. Self-supervised 4D spatio-temporal feature learning via order prediction of sequential point cloud clips. In WACV, 2021. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 309, + 287, + 352 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 309, + 287, + 352 + ], + "spans": [ + { + "bbox": [ + 48, + 309, + 287, + 352 + ], + "type": "text", + "content": "[39] Rui Wang, Dongdong Chen, Zuxuan Wu, Yinpeng Chen, Xiyang Dai, Mengchen Liu, Yu-Gang Jiang, Luowei Zhou, and Lu Yuan. BEVT: BERT pretraining of video transformers. In CVPR, 2022. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 354, + 287, + 397 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 354, + 287, + 397 + ], + "spans": [ + { + "bbox": [ + 48, + 354, + 287, + 397 + ], + "type": "text", + "content": "[40] Yancheng Wang, Yang Xiao, Fu Xiong, Wenxiang Jiang, Zhiguo Cao, Joey Tianyi Zhou, and Junsong Yuan. 3DV: 3D dynamic voxel for action recognition in depth video. In CVPR, 2020. 1, 3, 6" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 399, + 287, + 441 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 399, + 287, + 441 + ], + "spans": [ + { + "bbox": [ + 48, + 399, + 287, + 441 + ], + "type": "text", + "content": "[41] Chen Wei, Haoqi Fan, Saining Xie, Chao-Yuan Wu, Alan Yuille, and Christoph Feichtenhofer. Masked feature prediction for self-supervised visual pre-training. In CVPR, 2022. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 444, + 287, + 476 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 444, + 287, + 476 + ], + "spans": [ + { + "bbox": [ + 48, + 444, + 287, + 476 + ], + "type": "text", + "content": "[42] Yimin Wei, Hao Liu, Tingting Xie, Qiuhong Ke, and Yulan Guo. Spatial-temporal transformer for 3D point cloud sequences. In WACV, 2022. 1, 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 478, + 287, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 478, + 287, + 510 + ], + "spans": [ + { + "bbox": [ + 48, + 478, + 287, + 510 + ], + "type": "text", + "content": "[43] Hao Wen, Yunze Liu, Jingwei Huang, Bo Duan, and Li Yi. Point primitive transformer for long-term 4D point cloud video understanding. In ECCV, 2022. 1, 3, 5" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 512, + 287, + 553 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 512, + 287, + 553 + ], + "spans": [ + { + "bbox": [ + 48, + 512, + 287, + 553 + ], + "type": "text", + "content": "[44] Saining Xie, Jiatao Gu, Demi Guo, Charles R Qi, Leonidas Guibas, and Or Litany. PointContrast: Unsupervised pretraining for 3D point cloud understanding. In ECCV, 2020. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 556, + 287, + 589 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 556, + 287, + 589 + ], + "spans": [ + { + "bbox": [ + 48, + 556, + 287, + 589 + ], + "type": "text", + "content": "[45] Zhenda Xie, Zheng Zhang, Yue Cao, Yutong Lin, Jianmin Bao, Zhuliang Yao, Qi Dai, and Han Hu. SimMIM: A simple framework for masked image modeling. In CVPR, 2022. 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 590, + 287, + 622 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 590, + 287, + 622 + ], + "spans": [ + { + "bbox": [ + 48, + 590, + 287, + 622 + ], + "type": "text", + "content": "[46] Yaoqing Yang, Chen Feng, Yiru Shen, and Dong Tian. FoldingNet: Point cloud auto-encoder via deep grid deformation. In CVPR, 2018. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 624, + 287, + 666 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 624, + 287, + 666 + ], + "spans": [ + { + "bbox": [ + 48, + 624, + 287, + 666 + ], + "type": "text", + "content": "[47] Xumin Yu, Lulu Tang, Yongming Rao, Tiejun Huang, Jie Zhou, and Jiwen Lu. Point-BERT: Pre-training 3D point cloud transformers with masked point modeling. In CVPR, 2022. 2, 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 670, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 287, + 712 + ], + "type": "text", + "content": "[48] Zhuoyang Zhang, Yuhao Dong, Yunze Liu, and Li Yi. Complete-to-partial 4D distillation for self-supervised point cloud sequence representation learning. arXiv preprint arXiv:2212.05330, 2022. 3" + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 72, + 545, + 161 + ], + "type": "list", + "angle": 0, + "index": 19, + "blocks": [ + { + "bbox": [ + 307, + 72, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 72, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 72, + 545, + 106 + ], + "type": "text", + "content": "[49] Zaiwei Zhang, Rohit Girdhar, Armand Joulin, and Ishan Misra. Self-supervised pretraining of 3D features on any point-cloud. In ICCV, 2021. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 107, + 545, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 161 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 161 + ], + "type": "text", + "content": "[50] Jia-Xing Zhong, Kaichen Zhou, Qingyong Hu, Bing Wang, Niki Trigoni, and Andrew Markham. No Pain, Big Gain: Classify dynamic point cloud sequences with static models by fitting feature-level space-time surfaces. In CVPR, 2022. 1, 3, 5, 6" + } + ] + } + ], + "index": 18 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "16589" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Masked Spiking Transformer/7ef4a39e-394a-4406-bcd4-3ff4096115d4_content_list.json b/2023/Masked Spiking Transformer/7ef4a39e-394a-4406-bcd4-3ff4096115d4_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..b3c65454356d38db0aba9f44453562cec4cce56d --- /dev/null +++ b/2023/Masked Spiking Transformer/7ef4a39e-394a-4406-bcd4-3ff4096115d4_content_list.json @@ -0,0 +1,1724 @@ +[ + { + "type": "text", + "text": "Masked Spiking Transformer", + "text_level": 1, + "bbox": [ + 334, + 130, + 635, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Ziqing Wang $^{1,2*}$ Yuetong Fang $^{1*}$ Jiahang Cao $^{1}$ Qiang Zhang $^{1}$ Zhongrui Wang $^{3,4\\dagger}$ Renjing Xu $^{1\\dagger}$", + "bbox": [ + 86, + 178, + 880, + 200 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1The Hong Kong University of Science and Technology (Guangzhou) 2North Carolina State University", + "bbox": [ + 174, + 215, + 792, + 232 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "3The University of Hong Kong 4ACCESS - AI Chip Center for Emerging Smart Systems", + "bbox": [ + 217, + 233, + 751, + 250 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "zwang247@ncsu.edu, {yfang870, jcao248, qzhang749}@connect.hkust-gz.edu.cn", + "bbox": [ + 163, + 271, + 803, + 286 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "zrwang@eee.hku.hk, renjingxu@ust.hk", + "bbox": [ + 331, + 290, + 638, + 303 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 339, + 313, + 354 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "The combination of Spiking Neural Networks (SNNs) and Transformers has attracted significant attention due to their potential for high energy efficiency and high-performance nature. However, existing works on this topic typically rely on direct training, which can lead to suboptimal performance. To address this issue, we propose to leverage the benefits of the ANN-to-SNN conversion method to combine SNNs and Transformers, resulting in significantly improved performance over existing state-of-the-art SNN models. Furthermore, inspired by the quantal synaptic failures observed in the nervous system, which reduce the number of spikes transmitted across synapses, we introduce a novel Masked Spiking Transformer (MST) framework. This incorporates a Random Spike Masking (RSM) method to prune redundant spikes and reduce energy consumption without sacrificing performance. Our experimental results demonstrate that the proposed MST model achieves a significant reduction of $26.8\\%$ in power consumption when the masking ratio is $75\\%$ while maintaining the same level of performance as the unmasked model. The code is available at: https://github.com/bic-L/Masked-Spiking-Transformer.", + "bbox": [ + 76, + 371, + 473, + 704 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 733, + 209, + 750 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Spiking neural networks (SNNs), considered as the next generation neural networks [30], are brain-inspired neural networks based on the dynamic characteristics of biological neurons [31, 17]. SNNs have attracted significant attention due to their unique properties in handling sparse data, which can yield great energy efficiency benefits on neuromorphic hardware. Due to their specialties, they have been widely", + "bbox": [ + 75, + 758, + 468, + 864 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/f1c7ed3952b75e5d050a894adccea07a6265f2ddd01dcdb238d5d7ee6dcaa56e.jpg", + "image_caption": [ + "Figure 1. Performance of MST and other SOTA SNN models regarding top-1 accuracy and time steps. The markers, represented by circles and star shapes, denote the direct training (DT) and the ANN-to-SNN (A2S) conversion method, respectively, where the marker size corresponds to the model size. Results show that the proposed MST model achieves higher accuracy than the other SNN models." + ], + "image_footnote": [], + "bbox": [ + 498, + 354, + 694, + 556 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/df80e8530cbd60dd165de468d9a4cd683e6048d0e4ca1ca9b356d83b5b4d7d05.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 699, + 354, + 897, + 558 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "utilized in various fields, such as classification [32, 18], object detection [3] and tracking [51], etc. Nevertheless, SNNs currently can hardly realize a comparable performance to that of artificial neural networks (ANNs), especially for complex tasks such as ImageNet [40].", + "bbox": [ + 496, + 700, + 890, + 777 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In order to improve the performance of SNNs, various training methods have been proposed, broadly categorized as the direct training method and the ANN-to-SNN conversion method. Direct training methods leverage a continuous relaxation of the non-smooth spiking mechanism to enable backpropagation with a surrogate gradient function for handling non-differentiability [36], but this can lead to unstable gradient propagation and relatively low accuracy", + "bbox": [ + 496, + 779, + 892, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Equal contribution.", + "bbox": [ + 94, + 875, + 207, + 887 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "† Corresponding author", + "bbox": [ + 96, + 887, + 220, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "1761", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "compared to leading ANNs [38]. Alternatively, ANN-to-SNN conversion methods convert pre-trained ANNs into SNNs for better performance while requiring more time steps, with increased power consumption to reduce conversion errors [46, 25, 2, 7]. Our focus is on implementing the ANN-to-SNN conversion method to narrow the performance gap between leading ANNs and SNNs, but the required long time steps pose challenges in reducing energy consumption. Therefore, identifying strategies to decrease power consumption while maintaining excellent performance is crucial.", + "bbox": [ + 75, + 90, + 472, + 256 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The biological nervous system offers valuable insights for addressing the challenges of implementing high-performance Spiking Transformers using the ANN-to-SNN conversion method. The quantal synaptic failure theory suggests that missing information during neuronal signal transmission may not impact the computational information transmitted to a postsynaptic neuron under certain conditions, but can reduce energy consumption and heat production [23]. Likewise, in the ANN-to-SNN conversion process, missing spikes can possibly be compensated for by leveraging the correlations between signals in the space and time domains during the information propagation over multiple time steps. In addition, neural network models possess lots of redundant connections: prior works reveal that the redundancy in the self-attention module of Transformers can be pruned without significantly impacting performance [34, 49]. Therefore, eliminating redundant information during the transmission of neuronal signals can possibly reduce overall energy consumption in the Spiking Transformer model while preserving high performance.", + "bbox": [ + 75, + 257, + 472, + 559 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In our work, we propose a Masked Spiking Transformer (MST), which incorporates a Random Spike Masking (RSM) method designed specifically for SNNs. The RSM method randomly selects only a subset of input spikes, significantly reducing the number of spikes involved in the computation process. We evaluate the MST model on both static and neuromorphic datasets, demonstrating its superiority over existing SNN models. Our experiments show that the RSM method can reduce energy consumption on the self-attention module and the MLP module in Transformer, enabling the SNNs to take advantage of energy efficiency and high performance. Furthermore, the proposed RSM method is not limited to Transformer, but can be extended to other backbones such as ResNet and VGG, highlighting its potential as a general technique to improve SNN efficiency. Our results demonstrate the potential of this approach to provide a new direction for developing high-performance and energy-efficient SNN models.", + "bbox": [ + 75, + 559, + 472, + 830 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The main contributions of this paper can be summarized as follows:", + "bbox": [ + 76, + 830, + 470, + 861 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "- We propose a Masked Spiking Transformer (MST) using the ANN-to-SNN conversion method. To the best", + "bbox": [ + 94, + 869, + 470, + 901 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/3f36b6897dc51e05c932bfa271512da956a15bc4fd01b24b1f0e6b13e8659968.jpg", + "image_caption": [ + "Figure 2. Overview of our MST. (a) Schematic of the model architecture of the Swin Transformer, which is the backbone of our model. (b) Schematic of the proposed Transformer blocks, where BN layers replace the original LN layers. (c) Conceptual illustration of the RSM method, which involves randomly masking the input spike. (d-e) The RSM method in self-attention and MLP module." + ], + "image_footnote": [], + "bbox": [ + 498, + 89, + 908, + 304 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "of our knowledge, it is the first exploration of applying the self-attention mechanism fully in SNNs utilizing the ANN-to-SNN conversion method.", + "bbox": [ + 529, + 439, + 890, + 484 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- The MST model is evaluated on both static and neuromorphic datasets, and the results show that it outperforms state-of-the-art (SOTA) SNNs on all datasets. In specific, the top-1 accuracy of the MST model is $1.21\\%$ , $7.3\\%$ , and $3.7\\%$ higher than the current SOTA SNN model on the CIFAR-10, CIFAR-100, and ImageNet datasets, respectively.", + "- We design a Random Spike Masking (RSM) method for SNNs trained with the ANN-to-SNN conversion method to prune the redundant spikes during inference and save energy consumption.", + "- Extensive experiments show that our proposed RSM is a versatile and general method that can be utilized in other spike-based deep networks, such as ResNet and VGG SNN model variants." + ], + "bbox": [ + 517, + 494, + 890, + 739 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 779, + 640, + 796 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Spiking Neural Networks SNNs have gained popularity in the field of brain-inspired intelligence due to their compatibility with neuromorphic hardware and biological properties. With the increasing interest in larger-scale and higher-performance SNNs, recent research has focused on developing novel training algorithms and architectures.", + "bbox": [ + 496, + 809, + 890, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "1762", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Zheng et al. proposed a threshold-dependent batch normalization (tdBN) method based on spatiotemporal backpropagation to train a large-scale SNN model with 50 layers [56]. Besides, Fang et al. proposed the SEW ResNet architecture for residual learning in deep SNNs to overcome the gradient vanishing problem [10]. Later, they introduced a training algorithm that learns the threshold of each spiking neuron to improve the performance of SNNs [11]. However, these methods mainly discuss the SNN models that are dominated by convolutional layers, such as the SNN variants of VGG [42] and ResNet [15]. Despite their improvements, the performance of these methods still struggles to match their ANN counterparts, limiting the application of SNNs. In this context, our proposed work focuses on implementing the self-attention mechanism in SNNs to design a Spiking Transformer that improves the performance of SNNs.", + "bbox": [ + 75, + 90, + 472, + 333 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Transformer Transformer [47] was first introduced in Natural Language Processing (NLP) and quickly gained popularity for its remarkable capabilities in capturing long-range dependencies. Its success in NLP has inspired researchers to explore its potential in computer vision. Vision Transformer (ViT) [8] was the first attempt to apply the Transformer to image classification. ViT has achieved impressive results on various computer vision benchmarks, demonstrating the effectiveness of the self-attention mechanism in image understanding. Following the success of ViT, a series of works [29, 14] proposed improvements to the original ViT architecture. Motivated by the success of Transformers and its variations, this paper proposes a new architecture for SNNs that leverages the capacities of the Transformer and the energy efficiency of SNNs.", + "bbox": [ + 75, + 352, + 472, + 580 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Spiking Transformer The combination of the Transformer and SNNs can achieve better performance, which has been discussed in prior studies, including STNet [54] and Spike-T [55]. These models utilized separate branches of SNNs and Transformers for feature extraction, leading to the inability to run independently on neuromorphic hardware and failing to exploit the energy efficiency benefits of SNNs fully. In addition, Mueller et al. [35] proposed a Spiking Transformer using the ANN-to-SNN conversion method, but they did not implement the self-attention module in SNNs. The recently proposed Spikformer [57] directly trained the Transformer in SNNs, but still struggles to achieve comparable performance to leading ANNs. To address these limitations, we apply the self-attention mechanism fully in SNNs by utilizing the ANN-to-SNN conversion method and propose the RSM method to improve both the performance and energy efficiency of the Spiking Transformer. Our model offers a new direction for developing high-performance SNNs using the ANN-to-SNN conversion method.", + "bbox": [ + 75, + 598, + 472, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Methods", + "text_level": 1, + "bbox": [ + 500, + 89, + 599, + 106 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Spiking Neuron Model", + "text_level": 1, + "bbox": [ + 500, + 117, + 712, + 133 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "For ANNs, the input $\\pmb{a}^{l-1}$ to layer $l$ is mapped to the output $\\pmb{a}^l$ by a linear transformation matrix $\\pmb{W}^l$ and a nonlinear activation function $f(\\cdot)$ , that is $(l = 1,2,3,\\dots,L)$ :", + "bbox": [ + 498, + 140, + 893, + 188 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {a} ^ {l} = f \\left(\\boldsymbol {W} ^ {l} \\boldsymbol {a} ^ {l - 1}\\right) \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 629, + 196, + 892, + 224 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $f(\\cdot)$ is often set as the ReLU activation function.", + "bbox": [ + 498, + 234, + 870, + 250 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In SNNs, the Integrate-and-Fire (IF) spiking neuron model is commonly used in ANN-to-SNN conversion [25, 2, 7]. The dynamics of the IF model are described by:", + "bbox": [ + 498, + 250, + 890, + 295 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\pmb {v} ^ {l} (t) = \\pmb {v} ^ {l} (t - 1) + \\pmb {W} ^ {l} \\theta^ {l - 1} \\pmb {s} ^ {l - 1} (t) - \\theta^ {l} \\pmb {s} ^ {l} (t) \\quad (2)\n$$\n", + "text_format": "latex", + "bbox": [ + 539, + 304, + 892, + 325 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\pmb{v}^l (t)$ denotes the membrane potential of neurons in layer $l$ at time step $t$ , which corresponds to the linear transformation matrix $\\pmb{W}^{l}$ , the threshold $\\theta^l$ , and the binary output spikes of neurons in the previous layer $l - 1$ , denoted as $\\pmb{s}^{l - 1}(t)$ . The $s^l (t)$ is defined as follows:", + "bbox": [ + 498, + 334, + 892, + 411 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {s} ^ {l} (t) = H \\left(\\boldsymbol {u} ^ {l} (t) - \\theta^ {l}\\right) \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 614, + 422, + 892, + 444 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\pmb{u}^{l}(t) = \\pmb{v}^{l}(t - 1) + \\pmb{W}^{l}\\theta^{l - 1}\\pmb{s}^{l - 1}(t)$ denotes the membrane potential of neurons before the trigger of a spike at time step $t$ , $H(\\cdot)$ denotes the Heaviside step function. The neurons generate output spikes whenever the membrane potential $\\pmb{u}^{l}(t)$ exceeds the threshold value $\\theta^l$ , and the membrane potential is reset by subtracting the threshold value to reduce information loss [41].", + "bbox": [ + 496, + 448, + 893, + 556 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2.ANN-to-SNN conversion", + "text_level": 1, + "bbox": [ + 500, + 568, + 723, + 584 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To achieve the ANN-SNN conversion, a relationship is established between the rectified linear unit (ReLU) activation of analog neurons in ANNs and the firing rate or postsynaptic potential of spiking neurons in SNNs. This is obtained by summing Eq. 2 from time step 1 to $T$ dividing $T$ on both sides, resulting in the following equation:", + "bbox": [ + 496, + 592, + 890, + 684 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\frac {\\boldsymbol {v} ^ {l} (T) - \\boldsymbol {v} ^ {l} (0)}{T} = \\frac {\\sum_ {t = 1} ^ {T} \\boldsymbol {W} ^ {l} \\theta^ {l - 1} \\boldsymbol {s} ^ {l - 1} (t)}{T} - \\frac {\\sum_ {t = 1} ^ {T} \\theta^ {l} \\boldsymbol {s} ^ {l} (t)}{T} \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 501, + 693, + 890, + 738 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The linear relationship between $\\phi^l (T)$ and $\\phi^{l - 1}(T)$ is established by defining $\\phi^l (T) = \\frac{\\sum_{t\\equiv 1}^T\\theta^l s^l(t)}{T}$ as the average postsynaptic potential:", + "bbox": [ + 496, + 738, + 890, + 789 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\phi^ {l} (T) = \\boldsymbol {W} ^ {l} \\phi^ {l - 1} (T) - \\frac {\\boldsymbol {v} ^ {l} (T) - \\boldsymbol {v} ^ {l} (0)}{T} \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 560, + 797, + 890, + 830 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The equivalence between Eq. 1 and 5 holds only as $\\mathrm{T}$ goes to infinity, resulting in a conversion error. To address this issue, we replace the ReLU activation function with the quantization clip-floor-shift (QCFS) [2] function in the ANNs.", + "bbox": [ + 496, + 839, + 892, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "1763", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.3. Model Architecture", + "text_level": 1, + "bbox": [ + 76, + 90, + 266, + 104 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "An overview of the MST is depicted in Fig. 2, where the Swin Transformer [29] is adopted as the backbone network. To convert the original network into a fully-spiking manner, we incorporate the QCFS activation functions after each linear or regularization layer during the training phase, which are replaced with Integrate-and-Fire (IF) neurons in the inference process, resulting in more efficient computation.", + "bbox": [ + 75, + 113, + 468, + 219 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The entire computation process in the spiking self-attention module can be formulated as:", + "bbox": [ + 76, + 220, + 468, + 250 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nQ _ {s p k} [ t ] = \\operatorname {I F} (X [ t ] * W _ {q}) \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 184, + 258, + 468, + 281 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nK _ {s p k} [ t ] = \\operatorname {I F} (X [ t ] * W _ {k})\n$$\n", + "text_format": "latex", + "bbox": [ + 187, + 277, + 359, + 296 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $Q_{spk}$ , $K_{spk}$ denote the spike matrices of the query and key at $t$ time step, $\\mathrm{IF}(\\cdot)$ is the IF neuron function, $W_{q}$ , $W_{k}$ denote the corresponding weight matrices. Attention score is defined as:", + "bbox": [ + 76, + 305, + 468, + 364 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nA _ {s p k} [ t ] = \\operatorname {I F} \\left(\\frac {Q _ {s p k} [ t ] * K _ {s p k} ^ {T} [ t ]}{\\sqrt {d}}\\right) \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 161, + 375, + 468, + 411 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $A_{spk}$ represents the spike matrix of the attention score calculated by the dot product of the query spike matrix and the key spike matrix, and $d$ is a scaling factor equal to the feature dimension of a given attention head.", + "bbox": [ + 76, + 420, + 468, + 479 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The calculation of LN and BN can be expressed by:", + "bbox": [ + 96, + 479, + 439, + 496 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\ny = \\frac {x - \\operatorname {E} [ x ]}{\\sqrt {\\operatorname {V a r} [ x ] + \\epsilon}} * \\gamma + \\beta \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 181, + 506, + 468, + 542 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $x$ denotes the input tensor to be normalized, $\\operatorname{E}[x]$ and $\\operatorname{Var}[x]$ represent the mean and variance of $x$ , $\\epsilon$ is a small constant added to the variance for numerical stability, $\\gamma$ and $\\beta$ are trainable scaling and bias parameters respectively, and $y$ is the normalized output of the layer.", + "bbox": [ + 76, + 551, + 468, + 628 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In LN, the mean and variance are calculated across the features of each sample in a batch. Therefore, each sample in the batch has its normalization parameters. On the other hand, BN calculates the mean and variance across all samples in a batch for each feature, which means the normalization parameters are shared across all samples in a batch.", + "bbox": [ + 75, + 628, + 468, + 719 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Normalization is important for ensuring the feasibility of ANN-to-SNN conversion. As illustrated in Fig. 3, different normalization approach results in vastly different membrane potential in the inference process. Normalizing along the channel dimension (LN) cause a distribution mismatch between ANN and SNN, which leads to performance degradation, while normalizing along the batch dimension (BN) preserves a similar result. Replace all LN layers with BN layers is a straightforward approach to normalize the post-activation distribution of ANNs during the conversion process, but for large datasets like ImageNet, there are convergence issues. We resolve this problem by simply adding", + "bbox": [ + 75, + 719, + 470, + 901 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/a576c5b44bc04911a17c4c203092f13c8b8f878f5651da5977efa40b9de7a87c.jpg", + "image_caption": [ + "(a) ANN" + ], + "image_footnote": [], + "bbox": [ + 506, + 87, + 624, + 180 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/b2ecc446fa9bf249c908ea65e9e95e622ec7ef559cc58188a2d15b59bdc0849f.jpg", + "image_caption": [ + "(b) SNN (BN)" + ], + "image_footnote": [], + "bbox": [ + 629, + 88, + 750, + 180 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/c99baa9b30e33ed9725b32faf7db4c5e59e8340b2b9906af866793d3ee425de7.jpg", + "image_caption": [ + "(b) SNN (LN)", + "Figure 3. Illustration of distributions of (a) post-activation distribution in ANN, and (b-c) cumulative membrane potential distributions of SNN model with BN and LN, respectively. The heatmap shows a similar distribution between ANN and SNN(BN) models, while the widely varying distribution between ANN and SNN(LN) models leads to performance degradation." + ], + "image_footnote": [], + "bbox": [ + 753, + 88, + 888, + 180 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "a BN layer after each linear layer in the MLP module, inspired by [53]. Mathematically, the first layer of the modified MLP module is formulated as follows:", + "bbox": [ + 496, + 305, + 892, + 349 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {M L P} (x) = \\operatorname {I F} (\\operatorname {L i n e a r} (\\operatorname {B N} (x))) \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 586, + 362, + 890, + 378 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $x$ represents the input tensor, Linear denotes the linear layer, BN represents the batch normalization layer. Notably, the MLP module consists of two linear layers, each followed by a BN layer and an IF neuron function.", + "bbox": [ + 496, + 391, + 892, + 452 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.4. Random Spike Masking Method", + "text_level": 1, + "bbox": [ + 500, + 468, + 785, + 484 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Implementing the Transformer in SNNs using the ANN-to-SNN conversion method presents a challenge due to the high power consumption demand. To address this issue, we propose the Random Spike Masking (RSM) method for reducing redundant spikes during inference.", + "bbox": [ + 496, + 492, + 890, + 566 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Traditional ANN pruning methods remove weights with low magnitudes, which are believed to have little impact on the final output of the model [58]. In contrast, our RSM method prunes input spikes randomly according to the masking ratio, where each spike $(s = 1)$ has the probability of turning into a failure state $(s = 0)$ that can be implemented using binary mask matrices.", + "bbox": [ + 496, + 566, + 892, + 672 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "It is important to note that our proposed RSM method for spike pruning in SNNs differs from Dropout [44] used in ANNs. Dropout is a regularization technique that randomly masks some neurons during training, but all neurons are used for inference, and the output needs to be scaled by the retained probability used during training. This means that Dropout cannot directly reduce the number of spikes in the network. Unlike Dropout, the RSM method reduces the computational cost of SNNs by randomly pruning input spikes in both training and inference, explicitly removing redundancy in input spikes while obtaining excellent performance.", + "bbox": [ + 496, + 674, + 892, + 853 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The RSM method, illustrated in Fig. 2(c-e), randomly generates a binary mask with the same shape as the input spike matrix based on the masking ratio. This determines", + "bbox": [ + 496, + 854, + 893, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "1764", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "table", + "img_path": "images/31d314a5100e770ca4f88c65c8bcc9e4282282103df0c7e2aafd93ecf1c2605b.jpg", + "table_caption": [], + "table_footnote": [ + "Table 1. Performance comparison between the proposed model and the SOTA models on different static datasets, where Swin-T (BN) refers to the self-implemented ANN baseline replacing LN with BN [29]." + ], + "table_body": "
DatasetModelMethodArchitecture#Param(M)Time StepsAccuracy(%)
CIFAR-10ANN [29]Direct TrainingSwin-T(BN)27.6/98.14
Diet-SNN [39]Direct TrainingVGG-1639.91093.44
tdBN [56]Direct TrainingResNet-1912.6492.92
TET [6]Direct TrainingResNet-1912.6694.50
DSR [32]Direct TrainingPreActResNet-1811.22095.40
Spikformer [57]Direct TrainingSpikformer-4-3849.3495.51
RMP [13]ANN-to-SNNVGG-1639.9204893.63
RNL [7]ANN-to-SNNPreActResNet-1811.225693.45
QCFS [2]ANN-to-SNNRestNet-1811.751296.06
MST (ours)ANN-to-SNNSwin-T(BN)27.66496.32
12897.06
25697.27
CIFAR-100ANN [29]Direct TrainingSwin-T(BN)27.6/88.72
Diet-SNN [39]Direct TrainingVGG-1639.9569.67
tdBN [56]Direct TrainingResNet-1912.6470.86
TET [6]Direct TrainingResNet-1912.6674.72
DSR [32]Direct TrainingPreActResNet-1811.22078.50
SpikformerDirect TrainingSpikformer-4-3849.3478.21
RMP [13]ANN-to-SNNVGG-1639.9204870.93
RNL [7]ANN-to-SNNPreActResNet-1811.225675.10
QCFS [2]ANN-to-SNNRestNet-1811.751279.61
MST (ours)ANN-to-SNNSwin-T(BN)27.66485.40
12886.73
25686.91
ImageNetANN [29]Direct TrainingSwin-T(BN)28.5/80.51
Diet-SNN [39]Direct TrainingVGG-1639.9569.00
tdBN [56]Direct TrainingSEW-ResNet-3421.8467.04
TET [6]Direct TrainingSEW-ResNet-3421.8468.00
DSR [32]Direct TrainingPreActResNet-1811.25067.74
Spikformer [57]Direct TrainingSpikformer-8-76866.3474.81
RMP [13]ANN-to-SNNVGG-1639.9204873.09
QCFS [2]ANN-to-SNNRestNet-1811.7102474.32
MST (ours)ANN-to-SNNSwin-T(BN)28.512877.88
25678.37
51278.51
", + "bbox": [ + 94, + 90, + 875, + 654 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "which spikes are transmitted for calculation in subsequent neurons, enabling high matrix sparsity. With a masking ratio of $50\\%$ , for example, each spike has a $50\\%$ chance of being masked, reducing the number of spikes and power consumption. Hence, combining both the SNN-based self-attention mechanism with the RSM approach promises a balance between performance and energy efficiency.", + "bbox": [ + 75, + 709, + 470, + 815 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 829, + 209, + 847 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We conduct extensive experiments on both static datasets including CIFAR-10 [22], CIFAR-100 [21], and ImageNet datasets [5], and neuromorphic datasets including", + "bbox": [ + 75, + 854, + 470, + 902 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "CIFAR10-DVS [24], N-Caltech101 [37], N-Cars [43], ActionRecognition [33], and ASL-DVS [1] datasets, to validate the effectiveness of the MST model. In addition, we evaluate the effect of the RSM approach on accuracy and energy efficiency using the SpikingJelly framework [9]. More details of the training can be found in the supplementary.", + "bbox": [ + 496, + 709, + 890, + 816 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Performance on Static Datasets", + "text_level": 1, + "bbox": [ + 500, + 830, + 774, + 845 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Tab. 1 presents a comprehensive comparison of the MST model with the current SOTA SNN models on the CIFAR-10/100 and ImageNet datasets. The results show that the", + "bbox": [ + 500, + 854, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "1765", + "bbox": [ + 483, + 945, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/b248ac5f83f67e1ee1b66ea3bbda47e970d97ba5aa8f1d281ea3df34d55f2ba3.jpg", + "image_caption": [ + "Figure 4. Model Architecture for Neuromorphic Datasets." + ], + "image_footnote": [], + "bbox": [ + 102, + 89, + 444, + 224 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "proposed MST model outperforms all other models in terms of top-1 accuracy on all three datasets.", + "bbox": [ + 75, + 279, + 467, + 309 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Direct training models, such as Diet-SNN [39], tdBN [56], TET [6], and DSR [32], require lower time steps, but their top-1 accuracy is relatively low, compared to that of the MST model, in which tdBN [56] is $10\\%$ less accurate on the CIFAR-100 and ImageNet datasets.", + "bbox": [ + 75, + 309, + 467, + 383 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Conversely, models employing the ANN-to-SNN conversion method typically necessitate a greater number of time steps to reach optimal performance, including RMP [13], RNL [7], and QCFS [2]. The MST model also employs this method but requires only 64 time steps to achieve superior performance, which is far fewer than RMP [13]. This suggests that the MST model can achieve the highest accuracy in a reasonable number of time steps.", + "bbox": [ + 75, + 385, + 467, + 505 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Compared to transformer-based SNN models such as Spikformer [57], the MST model achieves higher top-1 accuracy on all three datasets. Specifically, the top-1 accuracy of the MST model is $1.8\\%$ , $8.7\\%$ , and $3.7\\%$ higher than Spikformer on the CIFAR-10, CIFAR-100, and ImageNet datasets, respectively. Moreover, the MST model has significantly fewer parameters compared to the 8-layer Spikformer [57] model.", + "bbox": [ + 75, + 506, + 467, + 626 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Performance on Neuromorphic Datasets", + "text_level": 1, + "bbox": [ + 76, + 635, + 421, + 652 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We showcase the suitability of the MST model for processing event-based data by evaluating its performance on neuromorphic datasets. Fig. 4 shows the framework for the MST model to process the neuromorphic datasets. We utilize a frame-based representation for preprocessing, where the event streams are transformed into a sequence of high-rate frames. Each event in the stream consists of four dimensions, including two spatial coordinates (x, y), timestamp, and polarity. The frames are integrated into an input tensor of size $(\\mathrm{n}\\times \\mathrm{C},\\mathrm{H},\\mathrm{W})$ ,where n is the number of frames, C is the number of original channels (which equals two, representing polarity), and H and W represent the height and width of the input, respectively. To align the input dimension with the model, an additional reduction layer is added to the first layer of the entire model, which reduces the channel dimension to 3. This enables us", + "bbox": [ + 75, + 659, + 467, + 898 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/f62b731f80bd232d234581ecd081d07909b7de8d58f457da747a491af8a1eb9f.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
DatasetModelTime StepsAccuracy (%)
CIFAR10-DVSSwin-T (BN)/88.98
TA-SNN [52]1072.00
PLIF [11]2074.80
Dspkie [26]1075.40
DSR [32]1077.30
TET [6]1083.17
NDA [27]1081.70
Spikformer [57]1080.90
12886.60
MST (ours)25687.20
51288.12
N-CALTECH101Swin-T (BN)/92.00
SALT [19]2055.00
NDA [27]1083.70
6484.71
MST (ours)12889.42
25691.38
N-CARSSwin-T (BN)/97.14
CarSNN [48]1086.00
NDA [27]1091.90
3294.67
MST (ours)6496.58
12897.28
Action RecognitionSwin-T (BN)/90.14
STCA [12]1071.20
Mb-SNN [28]1078.10
6484.76
MST (ours)12886.92
25688.21
ASL-DVSSwin-T (BN)/99.90
Meta-SNN [45]10096.04
6498.04
MST (ours)12898.51
25699.10
", + "bbox": [ + 516, + 89, + 877, + 618 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2. Performance comparison between the proposed model and the SOTA models on different neuromorphic datasets.", + "bbox": [ + 500, + 619, + 890, + 648 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "to leverage pre-training weights from the ImageNet dataset, accelerating the training convergence. Data augmentation for SNNs [27] is also applied to improve the accuracy. The ensuing experimental results demonstrate that the proposed fine-tuning approach for ANN-to-SNN conversion achieves remarkably high accuracy.", + "bbox": [ + 496, + 666, + 890, + 758 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The experimental results presented in Tab. 2 demonstrate the effectiveness of the proposed MST model in processing neuromorphic datasets. We compare the MST model with several SOTA SNN models on five popular neuromorphic datasets, including CIFAR10-DVS, N-Caltech101, NCars, Action Recognition, and ASL-DVS dataset. The experimental results show that the MST model achieves the highest top-1 accuracy on all datasets.", + "bbox": [ + 496, + 760, + 890, + 881 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "CIFAR10-DVS, N-Caltech101, and N-Cars datasets are", + "bbox": [ + 517, + 885, + 890, + 898 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "1766", + "bbox": [ + 483, + 945, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "constructed by converting the static datasets into event data by using event-based cameras. Tab. 2 shows that the MST model outperforms other SOTA SNN models significantly, achieving improvements of $4.95\\%$ , $7.68\\%$ , and $5.38\\%$ on CIFAR10-DVS, N-Caltech101, and N-Cars, respectively. The Action Recognition dataset consists of a series of human actions captured by event-based cameras. By adopting the data preprocessing method of [20], our MST model achieves a top-1 accuracy of $88.21\\%$ , which is far higher than other models. Additionally, the ASL-DVS dataset is a large 24-class dataset of gestures and the experimental results demonstrate that our MST model outperforms other SOTA models by $3.06\\%$ .", + "bbox": [ + 75, + 90, + 472, + 287 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "These results highlight the effectiveness of our proposed MST model in processing various types of neuromorphic datasets.", + "bbox": [ + 76, + 287, + 470, + 333 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Effectiveness of the Random Spike Masking Method", + "text_level": 1, + "bbox": [ + 76, + 345, + 470, + 377 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "The ANN-to-SNN conversion method typically involves a large number of time steps, leading to high power consumption. To address this issue, we propose the RSM method for spike pruning, and we demonstrate its effectiveness in the following section.", + "bbox": [ + 75, + 383, + 468, + 460 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Drawing inspiration from knowledge distillation [16], we use the model without masked as a teacher model, and the model after masked as a student model. By fine-tuning the student model, the masked model achieves high performance comparable to the original model without masking in terms of accuracy. This finding highlights the efficacy of the knowledge distillation technique in training masked models without compromising their performance. Consequently, we employ the fine-tuning approach as the training method for our subsequent comparative analysis.", + "bbox": [ + 75, + 460, + 468, + 611 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We evaluate the RSM method in two critical modules in the Transformer: the self-attention (SA) module and the Multi-layer Perceptron (MLP) module. As shown in Fig. 2(d-e), we apply the RSM method to the Query, Key, and Attention matrices in the SA module, as well as the output spike matrix of the first fully connected layer within each block of the MLP module.", + "bbox": [ + 75, + 612, + 468, + 717 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Fig. 5(a) and (b) depict the variation in accuracy for different masking ratios on the CIFAR-10 and CIFAR-100 datasets, respectively. The experimental results demonstrate that the accuracy decreases with the increasing masking ratio for both the SA and MLP modules, but their sensitivity to masking ratio changes differs. Specifically, the accuracy of the SA module remains stable over a certain range of masking ratios. In contrast, the accuracy of the MLP module declines more sharply and is more sensitive to masking ratio changes. Consistent with prior research [34, 49], the redundancy in the SA module enables the MST to withstand the losses caused by missing input spikes with", + "bbox": [ + 75, + 719, + 470, + 901 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/6faf2ceee2114643d5131e26d5123b257fa82443ebfe7cc4e72df0ed9dc2610b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 506, + 90, + 691, + 234 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/33a1b502007c475da3927f56b6ae28b7631c937ae34c98efc8d03ceb58f21856.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 508, + 234, + 691, + 375 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/ba202c8b34f3612eaad0b9798d9017e973b81cd93626f5adc0bc5c8fa0356297.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 697, + 90, + 883, + 234 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/12937ad9b9a231509fed4aa82780f80d28c533b529eb6c6516ed611f8811ca20.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 707, + 234, + 883, + 375 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/23340100e6adda5fbff85a8e0a895c1b4f79f391baadfe93e070b1d9cd97309e.jpg", + "image_caption": [ + "Figure 5. The effectiveness of the RSM method in (a) SA and (b) MLP modules of the MST model, as well as in Spiking (c) ResNet-18 and (d) VGG-16 models, with varying masking ratios. The inset photographs show the standard deviation of accuracy in 10 runs.", + "Figure 6. Comparison of the accuracy of masking different numbers of blocks on the CIFAR-100 dataset." + ], + "image_footnote": [], + "bbox": [ + 517, + 460, + 874, + 631 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "out significantly affecting the overall performance of the SNN.", + "bbox": [ + 498, + 685, + 890, + 715 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In addition to the variation in sensitivity to changes in the masking ratio between different modules, our experiments also demonstrate that the sensitivity can vary depending on the dataset used. The CIFAR-10 dataset is relatively less sensitive to changes in the masking ratio, with only a $0.1\\%$ decrease in accuracy when the masking ratio reaches $80\\%$ . In contrast, the CIFAR-100 dataset is more sensitive to changes in the masking ratio, experiencing a more substantial accuracy decline as the masking ratio increases.", + "bbox": [ + 496, + 717, + 890, + 853 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We also investigate the potential of the RSM method as a general approach for reducing power consumption in the context of ANN-to-SNN conversion. By applying the RSM", + "bbox": [ + 498, + 854, + 890, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "1767", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/0c76c4745d76bc341e791b408da8cadc814b3a01707cbef862c2cfea8c827d8f.jpg", + "table_caption": [], + "table_footnote": [ + "Table 3. Comparison of power consumption and accuracy between models with a Masking ratio of $0\\%$ , $50\\%$ , and $75\\%$ on the CIFAR-10 dataset, respectively. $(\\dots)$ in the table denotes the power consumption/accuracy compared to the unmasked model (with $0\\%$ random ratio)." + ], + "table_body": "
ModelRandom RatioP (α Watts)Accuracy (%)
MST0%3.9G (×1)97.27 (+0)
50%3.2G (×0.82)97.25 (-0.02)
75%2.9G (×0.74)97.29 (+0.02)
ResNet-180%58.2M (×1)96.48 (+0)
50%40.7M (×0.70)92.88 (-3.60)
75%34.1M (×0.58)82.68 (-13.80)
VGG-160%24.4M (×1)95.46 (+0)
50%18.9M (×0.77)89.56 (-5.90)
75%16.7M (×0.68)79.09 (-16.37)
", + "bbox": [ + 78, + 90, + 482, + 258 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "method to other SNN models like Spiking ResNet-18 and VGG-16 and introducing a masking ratio to each convolution layer, we aim to decrease the transmitted spikes. Our results, presented in Fig. 5, demonstrate that the redundancy of these models can also be leveraged to maintain performance while reducing power consumption within a specific range. This indicates the potential of the RSM method for widespread applications in various SNN models for improving energy efficiency.", + "bbox": [ + 75, + 352, + 468, + 488 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Fig. 6 illustrates the impact of masking different numbers of blocks on the accuracy of the MST model. Our results indicate a non-linear, positive relationship between the number of masked blocks and performance loss. Notably, masking the first 2-5 blocks causes a slight performance loss, and the loss increases with more masked blocks until saturation at around 9-10 blocks. These observations provide valuable insights for designing partially masked blocks.", + "bbox": [ + 75, + 489, + 468, + 625 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "To better evaluate the effects of the RSM method on energy consumption reduction, we utilize theoretical estimates of energy consumption on neuromorphic chips based on previous studies [4, 7]. Assuming that a spike activity consumes $\\alpha$ Joules and 1 time step takes $1\\mathrm{ms}$ . Then the power model is defined as:", + "bbox": [ + 75, + 625, + 468, + 715 + ], + "page_idx": 7 + }, + { + "type": "equation", + "text": "\n$$\nP = \\frac {\\text {t o t a l s p i k e s}}{1 \\times 1 0 ^ {- 3}} \\times \\alpha (\\text {W a t t s}) \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 169, + 728, + 468, + 758 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Tab. 3 presents the power consumption and accuracy of the MST, ResNet-18, and VGG-16 at $0\\%$ , $50\\%$ , and $75\\%$ masking ratios on the CIFAR-10 dataset. The RSM method is applied to the SA module in the MST and each block in ResNet-18 and VGG-16. The results demonstrate that the RSM method has a direct effect on the number of spikes transmitted, which in turn reduces power consumption. In specific, applying the RSM method to the MST", + "bbox": [ + 75, + 779, + 470, + 901 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/d1263df0a69bbd320b189d3a5abc5227b2d808365ee9953a28f2c382fe0f240f.jpg", + "image_caption": [ + "Figure 7. Comparison of attention maps between the MST model with $0\\%$ , $50\\%$ , and $75\\%$ masking ratio (from top to bottom) with 5 different time steps." + ], + "image_footnote": [], + "bbox": [ + 504, + 87, + 883, + 244 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "model can reduce power consumption by $26.8\\%$ without any loss in performance when the masking ratio reaches $75\\%$ . This finding suggests that there exist substantial redundant spikes in the SA module that can be pruned for better energy efficiency. As for ResNet-18 and VGG-16, the RSM method also yields significant power reduction. For instance, ResNet-18 can reduce power consumption by $30.1\\%$ with a moderate accuracy loss of $3.6\\%$ . However, excessive masking leads to a significant drop in accuracy.", + "bbox": [ + 496, + 313, + 890, + 450 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In summary, our results demonstrate that the proposed RSM method is effective when applied to the SA module in the Transformer, as well as other SNN models. By eliminating redundant spikes, the RSM method reduces power consumption while preserving performance, making it a promising approach for energy-efficient ANN-to-SNN conversion.", + "bbox": [ + 496, + 450, + 890, + 554 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "To visualize the impact of different masking ratios on attention maps, we compared the models with $0\\%$ , $50\\%$ , and $75\\%$ masking ratios using the Spike Activation Maps (SAM) method. The results, shown in Fig. 7, demonstrate that the models with different masking ratios concentrate on similar areas of the object at the same time step, with the red parts outlining the object. Comparison with the ANN model using the ScoreCAM method [50] reveals that both models focus on similar key information. These results suggest that the proposed RSM method preserves the regions of interest within the model, contributing to accuracy preservation.", + "bbox": [ + 496, + 556, + 890, + 723 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Discussion", + "text_level": 1, + "bbox": [ + 500, + 738, + 612, + 753 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this paper, we proposed the Masked Spiking Transformer (MST) with the Random Spike Masking (RSM) method. By pruning input spikes, the proposed RSM method effectively reduces power consumption while maintaining the performance of the model within a certain range.", + "bbox": [ + 496, + 763, + 890, + 840 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Though our experiments highlight the superiority of the MST model over state-of-the-art SNN models, our model still has limitations that need addressing. A key constraint is the relatively long time steps needed by the ANN-to-SNN", + "bbox": [ + 496, + 840, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "1768", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "conversion method, limiting the suitability of the proposed model for real-time applications with strict timing demands.", + "bbox": [ + 76, + 90, + 468, + 119 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Furthermore, even though the RSM method reduces the number of spikes and energy consumption, the experiment in this article merely investigates its applicability of ANN-to-SNN conversion, thus exhibiting relatively high energy consumption compared to direct-trained SNN models, which take fewer time steps. Consequently, future research could apply the RSM method to direct training methods to optimize energy consumption further and make SNNs more practical for real-world applications. Additionally, adopting different masking ratios across layers may achieve a better balance between performance and energy efficiency.", + "bbox": [ + 75, + 122, + 470, + 303 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 319, + 194, + 335 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this work, we propose a Masked Spiking Transformer (MST) framework that combines the energy efficiency of SNNs with the high-performance self-attention mechanism of Transformers using the ANN-to-SNN method. Additionally, we introduce a Random Spike Masking (RSM) method to prune input spikes, thus reducing power consumption. The experimental results demonstrate that the MST model outperforms current SOTA SNN models on both static and neuromorphic datasets. Furthermore, the proposed RSM method shows significant power reduction while maintaining performance in different modules of the Transformer and other SNN models. Our work opens up new possibilities for developing high-performance SNN models, paving the way for future research in this area.", + "bbox": [ + 75, + 344, + 470, + 555 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "7. Acknowledgement", + "text_level": 1, + "bbox": [ + 76, + 571, + 256, + 589 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work is supported by the Guangzhou-HKUST(GZ) Joint Funding Program (Grant No. 2023A03J0682), HK RGC (Grant Nos. 27206321, 17205922, 17212923), NSFC (Grant No. 62122004), National Key R&D Program of China (Grant No. SQ2022YFB3600159). This research is also partially supported by ACCESS - AI Chip Center for Emerging Smart Systems, sponsored by Innovation and Technology Fund (ITF), Hong Kong SAR.", + "bbox": [ + 75, + 597, + 468, + 719 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 76, + 734, + 174, + 750 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Yin Bi, Aaron Chadha, Alhabib Abbas, Eirina Bourtsovatze, and Yiannis Andreopoulos. Graph-based object classification for neuromorphic vision sensing. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 491-501, 2019.", + "[2] Tong Bu, Wei Fang, Jianhao Ding, PengLin Dai, Zhaofei Yu, and Tiejun Huang. Optimal ANN-SNN Conversion for High-accuracy and Ultra-low-latency Spiking Neural Networks. In International Conference on Learning Representations, 2021." + ], + "bbox": [ + 84, + 758, + 468, + 898 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[3] Yongqiang Cao, Yang Chen, and Deepak Khosla. Spiking deep convolutional neural networks for energy-efficient object recognition. International Journal of Computer Vision, 113(1):54-66, 2015.", + "[4] Yongqiang Cao, Yang Chen, and Deepak Khosla. Spiking deep convolutional neural networks for energy-efficient object recognition. International Journal of Computer Vision, 113:54-66, 2015.", + "[5] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In 2009 IEEE Conference on Computer Vision and Pattern Recognition, pages 248–255. IEEE, 2009.", + "[6] Shikuang Deng, Yuhang Li, Shanghai Zhang, and Shi Gu. Temporal Efficient Training of Spiking Neural Network via Gradient Re-weighting. arXiv preprint arXiv:2202.11946, 2022.", + "[7] Jianhao Ding, Zhaofei Yu, Yonghong Tian, and Tiejun Huang. Optimal ann-snn conversion for fast and accurate inference in deep spiking neural networks. arXiv preprint arXiv:2105.11654, 2021.", + "[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, and Sylvain Gelly. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020.", + "[9] Wei Fang, Yanqi Chen, Jianhao Ding, Ding Chen, Zhaofei Yu, Huihui Zhou, Timothée Masquelier, Yonghong Tian, and other contributors. Spikingjelly. https://github.com/fangwei123456/spikingjelly, 2020. Accessed: 2023-02-21.", + "[10] Wei Fang, Zhaofei Yu, Yanqi Chen, Tiejun Huang, Timothee Masquelier, and Yonghong Tian. Deep residual learning in spiking neural networks. Advances in Neural Information Processing Systems, 34:21056-21069, 2021.", + "[11] Wei Fang, Zhaofei Yu, Yanqi Chen, Timothée Masquelier, Tiejun Huang, and Yonghong Tian. Incorporating learnable membrane time constant to enhance learning of spiking neural networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2661-2671, 2021.", + "[12] Pengjie Gu, Rong Xiao, Gang Pan, and Huajin Tang. STCA: Spatio-Temporal Credit Assignment with Delayed Feedback in Deep Spiking Neural Networks. In Proceedings of the Twenty-Eighth International Joint Conference on Artificial Intelligence, pages 1366-1372, Macao, China, Aug. 2019. International Joint Conferences on Artificial Intelligence Organization.", + "[13] Bing Han, Gopalakrishnan Srinivasan, and Kaushik Roy. Rmp-snn: Residual membrane potential neuron for enabling deeper high-accuracy and low-latency spiking neural network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13558–13567, 2020.", + "[14] Ali Hassani, Steven Walton, Nikhil Shah, Abulikemu Abuduweili, Jiachen Li, and Humphrey Shi. Escaping the big data paradigm with compact transformers. arXiv preprint arXiv:2104.05704, 2021." + ], + "bbox": [ + 501, + 92, + 893, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "1769", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016.", + "[16] Geoffrey Hinton, Oriol Vinyals, and Jeff Dean. Distilling the Knowledge in a Neural Network, Mar. 2015.", + "[17] Eugene M. Izhikevich. Simple model of spiking neurons. IEEE Transactions on neural networks, 14(6):1569-1572, 2003.", + "[18] Youngeun Kim and Priyadarshini Panda. Optimizing deeper spiking neural networks for dynamic vision sensing. Neural Networks, 144:686-698, 2021.", + "[19] Youngeun Kim and Priyadarshini Panda. Optimizing deeper spiking neural networks for dynamic vision sensing. Neural Networks, 144:686-698, 2021.", + "[20] Karthik Sivarama Krishnan and Koushik Sivarama Krishnan. Benchmarking Conventional Vision Models on Neuromorphic Fall Detection and Action Recognition Dataset. In 2022 IEEE 12th Annual Computing and Communication Workshop and Conference (CCWC), pages 0518-0523. IEEE, 2022.", + "[21] Alex Krizhevsky and Geoffrey Hinton. Learning multiple layers of features from tiny images. 2009.", + "[22] Y. Lecun, L. Bottou, Y. Bengio, and P. Haffner. Gradient-based learning applied to document recognition. Proceedings of the IEEE, 86(11):2278-2324, Nov. 1998.", + "[23] William B. Levy and Robert A. Baxter. Energy-Efficient Neuronal Computation via Quantal Synaptic Failures. Journal of Neuroscience, 22(11):4746-4755, June 2002.", + "[24] Hongmin Li, Hanchao Liu, Xiangyang Ji, Guoqi Li, and Luping Shi. CIFAR10-DVS: An Event-Stream Dataset for Object Classification. Frontiers in Neuroscience, 11, 2017.", + "[25] Yuhang Li, Shikuang Deng, Xin Dong, Ruihao Gong, and Shi Gu. A free lunch from ANN: Towards efficient, accurate spiking neural networks calibration. In International Conference on Machine Learning, pages 6316-6325. PMLR, 2021.", + "[26] Yuhang Li, Yufei Guo, Shanghang Zhang, Shikuang Deng, Yongqing Hai, and Shi Gu. Differentiable spike: Rethinking gradient-descent for training spiking neural networks. Advances in Neural Information Processing Systems, 34:23426-23439, 2021.", + "[27] Yuhang Li, Youngeun Kim, Hyoungseob Park, Tamar Geller, and Priyadarshini Panda. Neuromorphic Data Augmentation for Training Spiking Neural Networks. arXiv preprint arXiv:2203.06145, 2022.", + "[28] Qianhui Liu, Dong Xing, Huajin Tang, De Ma, and Gang Pan. Event-based Action Recognition Using Motion Information and Spiking Neural Networks. In Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence, pages 1743-1749, Montreal, Canada, Aug. 2021. International Joint Conferences on Artificial Intelligence Organization.", + "[29] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10012-10022, 2021." + ], + "bbox": [ + 78, + 90, + 468, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[30] Wolfgang Maass. Networks of spiking neurons: The third generation of neural network models. Neural networks, 10(9):1659-1671, 1997.", + "[31] Warren S. McCulloch and Walter Pitts. A logical calculus of the ideas immanent in nervous activity. The bulletin of mathematical biophysics, 5(4):115-133, 1943.", + "[32] Qingyan Meng, Mingqing Xiao, Shen Yan, Yisen Wang, Zhouchen Lin, and Zhi-Quan Luo. Training High-Performance Low-Latency Spiking Neural Networks by Differentiation on Spike Representation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12444–12453, 2022.", + "[33] Shu Miao, Guang Chen, Xiangyu Ning, Yang Zi, Kejia Ren, Zhenshan Bing, and Alois Knoll. Neuromorphic vision datasets for pedestrian detection, action recognition, and fall detection. Frontiers in neurorobotics, 13:38, 2019.", + "[34] Paul Michel, Omer Levy, and Graham Neubig. Are sixteen heads really better than one? Advances in neural information processing systems, 32, 2019.", + "[35] Etienne Mueller, Viktor Studenyak, Daniel Auge, and Alois Knoll. Spiking Transformer Networks: A Rate Coded Approach for Processing Sequential Data. In 2021 7th International Conference on Systems and Informatics (ICSAI), pages 1-5, Nov. 2021.", + "[36] Emre O. Neftci, Hesham Mostafa, and Friedemann Zenke. Surrogate Gradient Learning in Spiking Neural Networks: Bringing the Power of Gradient-Based Optimization to Spiking Neural Networks. IEEE Signal Processing Magazine, 36(6):51-63, Nov. 2019.", + "[37] Garrick Orchard, Ajinkya Jayawant, Gregory K. Cohen, and Nitish Thakor. Converting Static Image Datasets to Spiking Neuromorphic Datasets Using Saccades. Frontiers in Neuroscience, 9, 2015.", + "[38] Wachirawit Ponghiran and Kaushik Roy. Spiking neural networks with improved inherent recurrence dynamics for sequential learning. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 8001-8008, 2022.", + "[39] Nitin Rathi and Kaushik Roy. DIET-SNN: Direct Input Encoding With Leakage and Threshold Optimization in Deep Spiking Neural Networks, Dec. 2020.", + "[40] Nitin Rathi, Gopalakrishnan Srinivasan, Priyadarshini Panda, and Kaushik Roy. Enabling deep spiking neural networks with hybrid conversion and spike timing dependent backpropagation. arXiv preprint arXiv:2005.01807, 2020.", + "[41] Bodo Rueckauer, Iulia-Alexandra Lungu, Yuhuang Hu, Michael Pfeiffer, and Shih-Chii Liu. Conversion of continuous-valued deep networks to efficient event-driven networks for image classification. Frontiers in neuroscience, 11:682, 2017.", + "[42] Karen Simonyan and Andrew Zisserman. Very Deep Convolutional Networks for Large-Scale Image Recognition, Apr. 2015.", + "[43] Amos Sironi, Manuele Brambilla, Nicolas Bourdis, Xavier Lagorce, and Ryad Benosman. HATS: Histograms of Averaged Time Surfaces for Robust Event-Based Object Classification. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1731-1740, 2018." + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "1770", + "bbox": [ + 483, + 945, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[44] Nitish Srivastava, Geoffrey Hinton, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. Dropout: A simple way to prevent neural networks from overfitting. The journal of machine learning research, 15(1):1929-1958, 2014.", + "[45] Kenneth M. Stewart and Emre O. Neftci. Meta-learning spiking neural networks with surrogate gradient descent. Neuro-morphic Computing and Engineering, 2(4):044002, 2022.", + "[46] Christoph Stöckl and Wolfgang Maass. Optimized spiking neurons can classify images with high accuracy through temporal coding with two spikes. Nature Machine Intelligence, 3(3):230-238, 2021.", + "[47] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, $\\backslash$ Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017.", + "[48] Alberto Viale, Alberto Marchisio, Maurizio Martina, Guido Masera, and Muhammad Shafique. Carsnn: An efficient spiking neural network for event-based autonomous cars on the loihi neuromorphic research processor. In 2021 International Joint Conference on Neural Networks (IJCNN), pages 1-10. IEEE, 2021.", + "[49] Elena Voita, David Talbot, Fedor Moiseev, Rico Sennrich, and Ivan Titov. Analyzing multi-head self-attention: Specialized heads do the heavy lifting, the rest can be pruned. arXiv preprint arXiv:1905.09418, 2019.", + "[50] Haofan Wang, Zifan Wang, Mengnan Du, Fan Yang, Zijian Zhang, Sirui Ding, Piotr Mardziel, and Xia Hu. Score-CAM: Score-Weighted Visual Explanations for Convolutional Neural Networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops, pages 24–25, 2020.", + "[51] Zheyu Yang, Yujie Wu, Guanrui Wang, Yukuan Yang, Guoqi Li, Lei Deng, Jun Zhu, and Luping Shi. DashNet: A hybrid artificial and spiking neural network for high-speed object tracking. arXiv preprint arXiv:1909.12942, 2019.", + "[52] Man Yao, Huanhuan Gao, Guangshe Zhao, Dingheng Wang, Yihan Lin, Zhaoxu Yang, and Guoqi Li. Temporal-wise attention spiking neural networks for event streams classification. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10221-10230, 2021.", + "[53] Zhuliang Yao, Yue Cao, Yutong Lin, Ze Liu, Zheng Zhang, and Han Hu. Leveraging batch normalization for vision transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 413-422, 2021.", + "[54] Jiqing Zhang, Bo Dong, Haiwei Zhang, Jianchuan Ding, Felix Heide, Baocai Yin, and Xin Yang. Spiking Transformers for Event-Based Single Object Tracking. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8801-8810, 2022.", + "[55] Jiyuan Zhang, Lulu Tang, Zhaofei Yu, Jiwen Lu, and Tiejun Huang. Spike Transformer: Monocular Depth Estimation for Spiking Camera. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part VII, pages 34-52. Springer, 2022.", + "[56] Hanle Zheng, Yujie Wu, Lei Deng, Yifan Hu, and Guoqi Li. Going deeper with directly-trained larger spiking neural networks. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 11062-11070, 2021." + ], + "bbox": [ + 78, + 90, + 468, + 898 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[57] Zhaokun Zhou, Yuesheng Zhu, Chao He, Yaowei Wang, Shuicheng Yan, Yonghong Tian, and Li Yuan. Spikformer: When Spiking Neural Network Meets Transformer. arXiv preprint arXiv:2209.15425, 2022.", + "[58] Michael Zhu and Suyog Gupta. To prune, or not to prune: Exploring the efficacy of pruning for model compression, Nov. 2017." + ], + "bbox": [ + 501, + 92, + 890, + 188 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "1771", + "bbox": [ + 483, + 945, + 513, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/Masked Spiking Transformer/7ef4a39e-394a-4406-bcd4-3ff4096115d4_model.json b/2023/Masked Spiking Transformer/7ef4a39e-394a-4406-bcd4-3ff4096115d4_model.json new file mode 100644 index 0000000000000000000000000000000000000000..54fe69b446126bf7419d60d1371649168464839f --- /dev/null +++ b/2023/Masked Spiking Transformer/7ef4a39e-394a-4406-bcd4-3ff4096115d4_model.json @@ -0,0 +1,2400 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.335, + 0.131, + 0.636, + 0.154 + ], + "angle": 0, + "content": "Masked Spiking Transformer" + }, + { + "type": "text", + "bbox": [ + 0.088, + 0.179, + 0.882, + 0.201 + ], + "angle": 0, + "content": "Ziqing Wang\\(^{1,2*}\\) Yuetong Fang\\(^{1*}\\) Jiahang Cao\\(^{1}\\) Qiang Zhang\\(^{1}\\) Zhongrui Wang\\(^{3,4\\dagger}\\) Renjing Xu\\(^{1\\dagger}\\)" + }, + { + "type": "text", + "bbox": [ + 0.175, + 0.216, + 0.794, + 0.233 + ], + "angle": 0, + "content": "1The Hong Kong University of Science and Technology (Guangzhou) 2North Carolina State University" + }, + { + "type": "text", + "bbox": [ + 0.218, + 0.234, + 0.753, + 0.251 + ], + "angle": 0, + "content": "3The University of Hong Kong 4ACCESS - AI Chip Center for Emerging Smart Systems" + }, + { + "type": "text", + "bbox": [ + 0.165, + 0.272, + 0.804, + 0.287 + ], + "angle": 0, + "content": "zwang247@ncsu.edu, {yfang870, jcao248, qzhang749}@connect.hkust-gz.edu.cn" + }, + { + "type": "text", + "bbox": [ + 0.332, + 0.291, + 0.639, + 0.304 + ], + "angle": 0, + "content": "zrwang@eee.hku.hk, renjingxu@ust.hk" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.34, + 0.314, + 0.356 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.372, + 0.474, + 0.705 + ], + "angle": 0, + "content": "The combination of Spiking Neural Networks (SNNs) and Transformers has attracted significant attention due to their potential for high energy efficiency and high-performance nature. However, existing works on this topic typically rely on direct training, which can lead to suboptimal performance. To address this issue, we propose to leverage the benefits of the ANN-to-SNN conversion method to combine SNNs and Transformers, resulting in significantly improved performance over existing state-of-the-art SNN models. Furthermore, inspired by the quantal synaptic failures observed in the nervous system, which reduce the number of spikes transmitted across synapses, we introduce a novel Masked Spiking Transformer (MST) framework. This incorporates a Random Spike Masking (RSM) method to prune redundant spikes and reduce energy consumption without sacrificing performance. Our experimental results demonstrate that the proposed MST model achieves a significant reduction of \\(26.8\\%\\) in power consumption when the masking ratio is \\(75\\%\\) while maintaining the same level of performance as the unmasked model. The code is available at: https://github.com/bic-L/Masked-Spiking-Transformer." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.734, + 0.21, + 0.75 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.759, + 0.47, + 0.866 + ], + "angle": 0, + "content": "Spiking neural networks (SNNs), considered as the next generation neural networks [30], are brain-inspired neural networks based on the dynamic characteristics of biological neurons [31, 17]. SNNs have attracted significant attention due to their unique properties in handling sparse data, which can yield great energy efficiency benefits on neuromorphic hardware. Due to their specialties, they have been widely" + }, + { + "type": "image", + "bbox": [ + 0.499, + 0.355, + 0.695, + 0.558 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.7, + 0.355, + 0.898, + 0.559 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.577, + 0.895, + 0.675 + ], + "angle": 0, + "content": "Figure 1. Performance of MST and other SOTA SNN models regarding top-1 accuracy and time steps. The markers, represented by circles and star shapes, denote the direct training (DT) and the ANN-to-SNN (A2S) conversion method, respectively, where the marker size corresponds to the model size. Results show that the proposed MST model achieves higher accuracy than the other SNN models." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.702, + 0.892, + 0.779 + ], + "angle": 0, + "content": "utilized in various fields, such as classification [32, 18], object detection [3] and tracking [51], etc. Nevertheless, SNNs currently can hardly realize a comparable performance to that of artificial neural networks (ANNs), especially for complex tasks such as ImageNet [40]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.893, + 0.903 + ], + "angle": 0, + "content": "In order to improve the performance of SNNs, various training methods have been proposed, broadly categorized as the direct training method and the ANN-to-SNN conversion method. Direct training methods leverage a continuous relaxation of the non-smooth spiking mechanism to enable backpropagation with a surrogate gradient function for handling non-differentiability [36], but this can lead to unstable gradient propagation and relatively low accuracy" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.875, + 0.208, + 0.888 + ], + "angle": 0, + "content": "*Equal contribution." + }, + { + "type": "page_footnote", + "bbox": [ + 0.098, + 0.888, + 0.221, + 0.9 + ], + "angle": 0, + "content": "† Corresponding author" + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.875, + 0.221, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "1761" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.257 + ], + "angle": 0, + "content": "compared to leading ANNs [38]. Alternatively, ANN-to-SNN conversion methods convert pre-trained ANNs into SNNs for better performance while requiring more time steps, with increased power consumption to reduce conversion errors [46, 25, 2, 7]. Our focus is on implementing the ANN-to-SNN conversion method to narrow the performance gap between leading ANNs and SNNs, but the required long time steps pose challenges in reducing energy consumption. Therefore, identifying strategies to decrease power consumption while maintaining excellent performance is crucial." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.258, + 0.473, + 0.56 + ], + "angle": 0, + "content": "The biological nervous system offers valuable insights for addressing the challenges of implementing high-performance Spiking Transformers using the ANN-to-SNN conversion method. The quantal synaptic failure theory suggests that missing information during neuronal signal transmission may not impact the computational information transmitted to a postsynaptic neuron under certain conditions, but can reduce energy consumption and heat production [23]. Likewise, in the ANN-to-SNN conversion process, missing spikes can possibly be compensated for by leveraging the correlations between signals in the space and time domains during the information propagation over multiple time steps. In addition, neural network models possess lots of redundant connections: prior works reveal that the redundancy in the self-attention module of Transformers can be pruned without significantly impacting performance [34, 49]. Therefore, eliminating redundant information during the transmission of neuronal signals can possibly reduce overall energy consumption in the Spiking Transformer model while preserving high performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.56, + 0.473, + 0.831 + ], + "angle": 0, + "content": "In our work, we propose a Masked Spiking Transformer (MST), which incorporates a Random Spike Masking (RSM) method designed specifically for SNNs. The RSM method randomly selects only a subset of input spikes, significantly reducing the number of spikes involved in the computation process. We evaluate the MST model on both static and neuromorphic datasets, demonstrating its superiority over existing SNN models. Our experiments show that the RSM method can reduce energy consumption on the self-attention module and the MLP module in Transformer, enabling the SNNs to take advantage of energy efficiency and high performance. Furthermore, the proposed RSM method is not limited to Transformer, but can be extended to other backbones such as ResNet and VGG, highlighting its potential as a general technique to improve SNN efficiency. Our results demonstrate the potential of this approach to provide a new direction for developing high-performance and energy-efficient SNN models." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.832, + 0.472, + 0.862 + ], + "angle": 0, + "content": "The main contributions of this paper can be summarized as follows:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.871, + 0.472, + 0.902 + ], + "angle": 0, + "content": "- We propose a Masked Spiking Transformer (MST) using the ANN-to-SNN conversion method. To the best" + }, + { + "type": "image", + "bbox": [ + 0.499, + 0.09, + 0.91, + 0.305 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.318, + 0.895, + 0.414 + ], + "angle": 0, + "content": "Figure 2. Overview of our MST. (a) Schematic of the model architecture of the Swin Transformer, which is the backbone of our model. (b) Schematic of the proposed Transformer blocks, where BN layers replace the original LN layers. (c) Conceptual illustration of the RSM method, which involves randomly masking the input spike. (d-e) The RSM method in self-attention and MLP module." + }, + { + "type": "text", + "bbox": [ + 0.531, + 0.44, + 0.892, + 0.485 + ], + "angle": 0, + "content": "of our knowledge, it is the first exploration of applying the self-attention mechanism fully in SNNs utilizing the ANN-to-SNN conversion method." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.495, + 0.892, + 0.601 + ], + "angle": 0, + "content": "- The MST model is evaluated on both static and neuromorphic datasets, and the results show that it outperforms state-of-the-art (SOTA) SNNs on all datasets. In specific, the top-1 accuracy of the MST model is \\(1.21\\%\\), \\(7.3\\%\\), and \\(3.7\\%\\) higher than the current SOTA SNN model on the CIFAR-10, CIFAR-100, and ImageNet datasets, respectively." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.61, + 0.892, + 0.672 + ], + "angle": 0, + "content": "- We design a Random Spike Masking (RSM) method for SNNs trained with the ANN-to-SNN conversion method to prune the redundant spikes during inference and save energy consumption." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.681, + 0.892, + 0.741 + ], + "angle": 0, + "content": "- Extensive experiments show that our proposed RSM is a versatile and general method that can be utilized in other spike-based deep networks, such as ResNet and VGG SNN model variants." + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.495, + 0.892, + 0.741 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.78, + 0.642, + 0.797 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Spiking Neural Networks SNNs have gained popularity in the field of brain-inspired intelligence due to their compatibility with neuromorphic hardware and biological properties. With the increasing interest in larger-scale and higher-performance SNNs, recent research has focused on developing novel training algorithms and architectures." + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "1762" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.334 + ], + "angle": 0, + "content": "Zheng et al. proposed a threshold-dependent batch normalization (tdBN) method based on spatiotemporal backpropagation to train a large-scale SNN model with 50 layers [56]. Besides, Fang et al. proposed the SEW ResNet architecture for residual learning in deep SNNs to overcome the gradient vanishing problem [10]. Later, they introduced a training algorithm that learns the threshold of each spiking neuron to improve the performance of SNNs [11]. However, these methods mainly discuss the SNN models that are dominated by convolutional layers, such as the SNN variants of VGG [42] and ResNet [15]. Despite their improvements, the performance of these methods still struggles to match their ANN counterparts, limiting the application of SNNs. In this context, our proposed work focuses on implementing the self-attention mechanism in SNNs to design a Spiking Transformer that improves the performance of SNNs." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.353, + 0.473, + 0.581 + ], + "angle": 0, + "content": "Transformer Transformer [47] was first introduced in Natural Language Processing (NLP) and quickly gained popularity for its remarkable capabilities in capturing long-range dependencies. Its success in NLP has inspired researchers to explore its potential in computer vision. Vision Transformer (ViT) [8] was the first attempt to apply the Transformer to image classification. ViT has achieved impressive results on various computer vision benchmarks, demonstrating the effectiveness of the self-attention mechanism in image understanding. Following the success of ViT, a series of works [29, 14] proposed improvements to the original ViT architecture. Motivated by the success of Transformers and its variations, this paper proposes a new architecture for SNNs that leverages the capacities of the Transformer and the energy efficiency of SNNs." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.599, + 0.473, + 0.901 + ], + "angle": 0, + "content": "Spiking Transformer The combination of the Transformer and SNNs can achieve better performance, which has been discussed in prior studies, including STNet [54] and Spike-T [55]. These models utilized separate branches of SNNs and Transformers for feature extraction, leading to the inability to run independently on neuromorphic hardware and failing to exploit the energy efficiency benefits of SNNs fully. In addition, Mueller et al. [35] proposed a Spiking Transformer using the ANN-to-SNN conversion method, but they did not implement the self-attention module in SNNs. The recently proposed Spikformer [57] directly trained the Transformer in SNNs, but still struggles to achieve comparable performance to leading ANNs. To address these limitations, we apply the self-attention mechanism fully in SNNs by utilizing the ANN-to-SNN conversion method and propose the RSM method to improve both the performance and energy efficiency of the Spiking Transformer. Our model offers a new direction for developing high-performance SNNs using the ANN-to-SNN conversion method." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.09, + 0.6, + 0.107 + ], + "angle": 0, + "content": "3. Methods" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.118, + 0.713, + 0.135 + ], + "angle": 0, + "content": "3.1. Spiking Neuron Model" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.141, + 0.894, + 0.189 + ], + "angle": 0, + "content": "For ANNs, the input \\( \\pmb{a}^{l-1} \\) to layer \\( l \\) is mapped to the output \\( \\pmb{a}^l \\) by a linear transformation matrix \\( \\pmb{W}^l \\) and a nonlinear activation function \\( f(\\cdot) \\), that is \\( (l = 1,2,3,\\dots,L) \\):" + }, + { + "type": "equation", + "bbox": [ + 0.63, + 0.198, + 0.893, + 0.226 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {a} ^ {l} = f \\left(\\boldsymbol {W} ^ {l} \\boldsymbol {a} ^ {l - 1}\\right) \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.235, + 0.871, + 0.25 + ], + "angle": 0, + "content": "where \\( f(\\cdot) \\) is often set as the ReLU activation function." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.25, + 0.892, + 0.296 + ], + "angle": 0, + "content": "In SNNs, the Integrate-and-Fire (IF) spiking neuron model is commonly used in ANN-to-SNN conversion [25, 2, 7]. The dynamics of the IF model are described by:" + }, + { + "type": "equation", + "bbox": [ + 0.54, + 0.305, + 0.893, + 0.326 + ], + "angle": 0, + "content": "\\[\n\\pmb {v} ^ {l} (t) = \\pmb {v} ^ {l} (t - 1) + \\pmb {W} ^ {l} \\theta^ {l - 1} \\pmb {s} ^ {l - 1} (t) - \\theta^ {l} \\pmb {s} ^ {l} (t) \\quad (2)\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.335, + 0.893, + 0.412 + ], + "angle": 0, + "content": "where \\(\\pmb{v}^l (t)\\) denotes the membrane potential of neurons in layer \\(l\\) at time step \\(t\\), which corresponds to the linear transformation matrix \\(\\pmb{W}^{l}\\), the threshold \\(\\theta^l\\), and the binary output spikes of neurons in the previous layer \\(l - 1\\), denoted as \\(\\pmb{s}^{l - 1}(t)\\). The \\(s^l (t)\\) is defined as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.616, + 0.424, + 0.893, + 0.445 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {s} ^ {l} (t) = H \\left(\\boldsymbol {u} ^ {l} (t) - \\theta^ {l}\\right) \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.449, + 0.894, + 0.557 + ], + "angle": 0, + "content": "where \\(\\pmb{u}^{l}(t) = \\pmb{v}^{l}(t - 1) + \\pmb{W}^{l}\\theta^{l - 1}\\pmb{s}^{l - 1}(t)\\) denotes the membrane potential of neurons before the trigger of a spike at time step \\(t\\), \\(H(\\cdot)\\) denotes the Heaviside step function. The neurons generate output spikes whenever the membrane potential \\(\\pmb{u}^{l}(t)\\) exceeds the threshold value \\(\\theta^l\\), and the membrane potential is reset by subtracting the threshold value to reduce information loss [41]." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.569, + 0.725, + 0.585 + ], + "angle": 0, + "content": "3.2.ANN-to-SNN conversion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.593, + 0.892, + 0.685 + ], + "angle": 0, + "content": "To achieve the ANN-SNN conversion, a relationship is established between the rectified linear unit (ReLU) activation of analog neurons in ANNs and the firing rate or postsynaptic potential of spiking neurons in SNNs. This is obtained by summing Eq. 2 from time step 1 to \\( T \\) dividing \\( T \\) on both sides, resulting in the following equation:" + }, + { + "type": "equation", + "bbox": [ + 0.502, + 0.694, + 0.892, + 0.739 + ], + "angle": 0, + "content": "\\[\n\\frac {\\boldsymbol {v} ^ {l} (T) - \\boldsymbol {v} ^ {l} (0)}{T} = \\frac {\\sum_ {t = 1} ^ {T} \\boldsymbol {W} ^ {l} \\theta^ {l - 1} \\boldsymbol {s} ^ {l - 1} (t)}{T} - \\frac {\\sum_ {t = 1} ^ {T} \\theta^ {l} \\boldsymbol {s} ^ {l} (t)}{T} \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.739, + 0.892, + 0.79 + ], + "angle": 0, + "content": "The linear relationship between \\(\\phi^l (T)\\) and \\(\\phi^{l - 1}(T)\\) is established by defining \\(\\phi^l (T) = \\frac{\\sum_{t\\equiv 1}^T\\theta^l s^l(t)}{T}\\) as the average postsynaptic potential:" + }, + { + "type": "equation", + "bbox": [ + 0.561, + 0.799, + 0.892, + 0.832 + ], + "angle": 0, + "content": "\\[\n\\phi^ {l} (T) = \\boldsymbol {W} ^ {l} \\phi^ {l - 1} (T) - \\frac {\\boldsymbol {v} ^ {l} (T) - \\boldsymbol {v} ^ {l} (0)}{T} \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.893, + 0.902 + ], + "angle": 0, + "content": "The equivalence between Eq. 1 and 5 holds only as \\( \\mathrm{T} \\) goes to infinity, resulting in a conversion error. To address this issue, we replace the ReLU activation function with the quantization clip-floor-shift (QCFS) [2] function in the ANNs." + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "1763" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.091, + 0.267, + 0.106 + ], + "angle": 0, + "content": "3.3. Model Architecture" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.114, + 0.47, + 0.22 + ], + "angle": 0, + "content": "An overview of the MST is depicted in Fig. 2, where the Swin Transformer [29] is adopted as the backbone network. To convert the original network into a fully-spiking manner, we incorporate the QCFS activation functions after each linear or regularization layer during the training phase, which are replaced with Integrate-and-Fire (IF) neurons in the inference process, resulting in more efficient computation." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.221, + 0.47, + 0.25 + ], + "angle": 0, + "content": "The entire computation process in the spiking self-attention module can be formulated as:" + }, + { + "type": "equation", + "bbox": [ + 0.186, + 0.259, + 0.469, + 0.282 + ], + "angle": 0, + "content": "\\[\nQ _ {s p k} [ t ] = \\operatorname {I F} (X [ t ] * W _ {q}) \\tag {6}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.188, + 0.279, + 0.361, + 0.297 + ], + "angle": 0, + "content": "\\[\nK _ {s p k} [ t ] = \\operatorname {I F} (X [ t ] * W _ {k})\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.306, + 0.47, + 0.366 + ], + "angle": 0, + "content": "where \\( Q_{spk} \\), \\( K_{spk} \\) denote the spike matrices of the query and key at \\( t \\) time step, \\( \\mathrm{IF}(\\cdot) \\) is the IF neuron function, \\( W_{q} \\), \\( W_{k} \\) denote the corresponding weight matrices. Attention score is defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.163, + 0.375, + 0.47, + 0.412 + ], + "angle": 0, + "content": "\\[\nA _ {s p k} [ t ] = \\operatorname {I F} \\left(\\frac {Q _ {s p k} [ t ] * K _ {s p k} ^ {T} [ t ]}{\\sqrt {d}}\\right) \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.421, + 0.47, + 0.48 + ], + "angle": 0, + "content": "where \\( A_{spk} \\) represents the spike matrix of the attention score calculated by the dot product of the query spike matrix and the key spike matrix, and \\( d \\) is a scaling factor equal to the feature dimension of a given attention head." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.481, + 0.441, + 0.497 + ], + "angle": 0, + "content": "The calculation of LN and BN can be expressed by:" + }, + { + "type": "equation", + "bbox": [ + 0.182, + 0.507, + 0.47, + 0.543 + ], + "angle": 0, + "content": "\\[\ny = \\frac {x - \\operatorname {E} [ x ]}{\\sqrt {\\operatorname {V a r} [ x ] + \\epsilon}} * \\gamma + \\beta \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.553, + 0.47, + 0.629 + ], + "angle": 0, + "content": "where \\( x \\) denotes the input tensor to be normalized, \\( \\operatorname{E}[x] \\) and \\( \\operatorname{Var}[x] \\) represent the mean and variance of \\( x \\), \\( \\epsilon \\) is a small constant added to the variance for numerical stability, \\( \\gamma \\) and \\( \\beta \\) are trainable scaling and bias parameters respectively, and \\( y \\) is the normalized output of the layer." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.63, + 0.47, + 0.72 + ], + "angle": 0, + "content": "In LN, the mean and variance are calculated across the features of each sample in a batch. Therefore, each sample in the batch has its normalization parameters. On the other hand, BN calculates the mean and variance across all samples in a batch for each feature, which means the normalization parameters are shared across all samples in a batch." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Normalization is important for ensuring the feasibility of ANN-to-SNN conversion. As illustrated in Fig. 3, different normalization approach results in vastly different membrane potential in the inference process. Normalizing along the channel dimension (LN) cause a distribution mismatch between ANN and SNN, which leads to performance degradation, while normalizing along the batch dimension (BN) preserves a similar result. Replace all LN layers with BN layers is a straightforward approach to normalize the post-activation distribution of ANNs during the conversion process, but for large datasets like ImageNet, there are convergence issues. We resolve this problem by simply adding" + }, + { + "type": "image", + "bbox": [ + 0.507, + 0.088, + 0.625, + 0.181 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.547, + 0.183, + 0.584, + 0.193 + ], + "angle": 0, + "content": "(a) ANN" + }, + { + "type": "image", + "bbox": [ + 0.63, + 0.089, + 0.75, + 0.181 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.659, + 0.183, + 0.717, + 0.193 + ], + "angle": 0, + "content": "(b) SNN (BN)" + }, + { + "type": "image", + "bbox": [ + 0.754, + 0.089, + 0.889, + 0.181 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.789, + 0.183, + 0.847, + 0.193 + ], + "angle": 0, + "content": "(b) SNN (LN)" + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.208, + 0.894, + 0.293 + ], + "angle": 0, + "content": "Figure 3. Illustration of distributions of (a) post-activation distribution in ANN, and (b-c) cumulative membrane potential distributions of SNN model with BN and LN, respectively. The heatmap shows a similar distribution between ANN and SNN(BN) models, while the widely varying distribution between ANN and SNN(LN) models leads to performance degradation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.306, + 0.893, + 0.351 + ], + "angle": 0, + "content": "a BN layer after each linear layer in the MLP module, inspired by [53]. Mathematically, the first layer of the modified MLP module is formulated as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.587, + 0.363, + 0.892, + 0.38 + ], + "angle": 0, + "content": "\\[\n\\operatorname {M L P} (x) = \\operatorname {I F} (\\operatorname {L i n e a r} (\\operatorname {B N} (x))) \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.392, + 0.893, + 0.453 + ], + "angle": 0, + "content": "where \\( x \\) represents the input tensor, Linear denotes the linear layer, BN represents the batch normalization layer. Notably, the MLP module consists of two linear layers, each followed by a BN layer and an IF neuron function." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.469, + 0.787, + 0.485 + ], + "angle": 0, + "content": "3.4. Random Spike Masking Method" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.493, + 0.892, + 0.568 + ], + "angle": 0, + "content": "Implementing the Transformer in SNNs using the ANN-to-SNN conversion method presents a challenge due to the high power consumption demand. To address this issue, we propose the Random Spike Masking (RSM) method for reducing redundant spikes during inference." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.568, + 0.893, + 0.674 + ], + "angle": 0, + "content": "Traditional ANN pruning methods remove weights with low magnitudes, which are believed to have little impact on the final output of the model [58]. In contrast, our RSM method prunes input spikes randomly according to the masking ratio, where each spike \\((s = 1)\\) has the probability of turning into a failure state \\((s = 0)\\) that can be implemented using binary mask matrices." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.675, + 0.893, + 0.854 + ], + "angle": 0, + "content": "It is important to note that our proposed RSM method for spike pruning in SNNs differs from Dropout [44] used in ANNs. Dropout is a regularization technique that randomly masks some neurons during training, but all neurons are used for inference, and the output needs to be scaled by the retained probability used during training. This means that Dropout cannot directly reduce the number of spikes in the network. Unlike Dropout, the RSM method reduces the computational cost of SNNs by randomly pruning input spikes in both training and inference, explicitly removing redundancy in input spikes while obtaining excellent performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.894, + 0.901 + ], + "angle": 0, + "content": "The RSM method, illustrated in Fig. 2(c-e), randomly generates a binary mask with the same shape as the input spike matrix based on the masking ratio. This determines" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "1764" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.096, + 0.091, + 0.877, + 0.655 + ], + "angle": 0, + "content": "
DatasetModelMethodArchitecture#Param(M)Time StepsAccuracy(%)
CIFAR-10ANN [29]Direct TrainingSwin-T(BN)27.6/98.14
Diet-SNN [39]Direct TrainingVGG-1639.91093.44
tdBN [56]Direct TrainingResNet-1912.6492.92
TET [6]Direct TrainingResNet-1912.6694.50
DSR [32]Direct TrainingPreActResNet-1811.22095.40
Spikformer [57]Direct TrainingSpikformer-4-3849.3495.51
RMP [13]ANN-to-SNNVGG-1639.9204893.63
RNL [7]ANN-to-SNNPreActResNet-1811.225693.45
QCFS [2]ANN-to-SNNRestNet-1811.751296.06
MST (ours)ANN-to-SNNSwin-T(BN)27.66496.32
12897.06
25697.27
CIFAR-100ANN [29]Direct TrainingSwin-T(BN)27.6/88.72
Diet-SNN [39]Direct TrainingVGG-1639.9569.67
tdBN [56]Direct TrainingResNet-1912.6470.86
TET [6]Direct TrainingResNet-1912.6674.72
DSR [32]Direct TrainingPreActResNet-1811.22078.50
SpikformerDirect TrainingSpikformer-4-3849.3478.21
RMP [13]ANN-to-SNNVGG-1639.9204870.93
RNL [7]ANN-to-SNNPreActResNet-1811.225675.10
QCFS [2]ANN-to-SNNRestNet-1811.751279.61
MST (ours)ANN-to-SNNSwin-T(BN)27.66485.40
12886.73
25686.91
ImageNetANN [29]Direct TrainingSwin-T(BN)28.5/80.51
Diet-SNN [39]Direct TrainingVGG-1639.9569.00
tdBN [56]Direct TrainingSEW-ResNet-3421.8467.04
TET [6]Direct TrainingSEW-ResNet-3421.8468.00
DSR [32]Direct TrainingPreActResNet-1811.25067.74
Spikformer [57]Direct TrainingSpikformer-8-76866.3474.81
RMP [13]ANN-to-SNNVGG-1639.9204873.09
QCFS [2]ANN-to-SNNRestNet-1811.7102474.32
MST (ours)ANN-to-SNNSwin-T(BN)28.512877.88
25678.37
51278.51
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.076, + 0.657, + 0.892, + 0.687 + ], + "angle": 0, + "content": "Table 1. Performance comparison between the proposed model and the SOTA models on different static datasets, where Swin-T (BN) refers to the self-implemented ANN baseline replacing LN with BN [29]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.71, + 0.471, + 0.816 + ], + "angle": 0, + "content": "which spikes are transmitted for calculation in subsequent neurons, enabling high matrix sparsity. With a masking ratio of \\(50\\%\\), for example, each spike has a \\(50\\%\\) chance of being masked, reducing the number of spikes and power consumption. Hence, combining both the SNN-based self-attention mechanism with the RSM approach promises a balance between performance and energy efficiency." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.83, + 0.21, + 0.848 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.471, + 0.903 + ], + "angle": 0, + "content": "We conduct extensive experiments on both static datasets including CIFAR-10 [22], CIFAR-100 [21], and ImageNet datasets [5], and neuromorphic datasets including" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.71, + 0.892, + 0.817 + ], + "angle": 0, + "content": "CIFAR10-DVS [24], N-Caltech101 [37], N-Cars [43], ActionRecognition [33], and ASL-DVS [1] datasets, to validate the effectiveness of the MST model. In addition, we evaluate the effect of the RSM approach on accuracy and energy efficiency using the SpikingJelly framework [9]. More details of the training can be found in the supplementary." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.831, + 0.776, + 0.846 + ], + "angle": 0, + "content": "4.1. Performance on Static Datasets" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Tab. 1 presents a comprehensive comparison of the MST model with the current SOTA SNN models on the CIFAR-10/100 and ImageNet datasets. The results show that the" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "1765" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.104, + 0.09, + 0.445, + 0.226 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.101, + 0.24, + 0.444, + 0.255 + ], + "angle": 0, + "content": "Figure 4. Model Architecture for Neuromorphic Datasets." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.28, + 0.468, + 0.31 + ], + "angle": 0, + "content": "proposed MST model outperforms all other models in terms of top-1 accuracy on all three datasets." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.31, + 0.468, + 0.385 + ], + "angle": 0, + "content": "Direct training models, such as Diet-SNN [39], tdBN [56], TET [6], and DSR [32], require lower time steps, but their top-1 accuracy is relatively low, compared to that of the MST model, in which tdBN [56] is \\(10\\%\\) less accurate on the CIFAR-100 and ImageNet datasets." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.386, + 0.468, + 0.506 + ], + "angle": 0, + "content": "Conversely, models employing the ANN-to-SNN conversion method typically necessitate a greater number of time steps to reach optimal performance, including RMP [13], RNL [7], and QCFS [2]. The MST model also employs this method but requires only 64 time steps to achieve superior performance, which is far fewer than RMP [13]. This suggests that the MST model can achieve the highest accuracy in a reasonable number of time steps." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.507, + 0.468, + 0.627 + ], + "angle": 0, + "content": "Compared to transformer-based SNN models such as Spikformer [57], the MST model achieves higher top-1 accuracy on all three datasets. Specifically, the top-1 accuracy of the MST model is \\(1.8\\%\\), \\(8.7\\%\\), and \\(3.7\\%\\) higher than Spikformer on the CIFAR-10, CIFAR-100, and ImageNet datasets, respectively. Moreover, the MST model has significantly fewer parameters compared to the 8-layer Spikformer [57] model." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.636, + 0.422, + 0.653 + ], + "angle": 0, + "content": "4.2. Performance on Neuromorphic Datasets" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.66, + 0.468, + 0.9 + ], + "angle": 0, + "content": "We showcase the suitability of the MST model for processing event-based data by evaluating its performance on neuromorphic datasets. Fig. 4 shows the framework for the MST model to process the neuromorphic datasets. We utilize a frame-based representation for preprocessing, where the event streams are transformed into a sequence of high-rate frames. Each event in the stream consists of four dimensions, including two spatial coordinates (x, y), timestamp, and polarity. The frames are integrated into an input tensor of size \\((\\mathrm{n}\\times \\mathrm{C},\\mathrm{H},\\mathrm{W})\\) ,where n is the number of frames, C is the number of original channels (which equals two, representing polarity), and H and W represent the height and width of the input, respectively. To align the input dimension with the model, an additional reduction layer is added to the first layer of the entire model, which reduces the channel dimension to 3. This enables us" + }, + { + "type": "table", + "bbox": [ + 0.517, + 0.09, + 0.878, + 0.619 + ], + "angle": 0, + "content": "
DatasetModelTime StepsAccuracy (%)
CIFAR10-DVSSwin-T (BN)/88.98
TA-SNN [52]1072.00
PLIF [11]2074.80
Dspkie [26]1075.40
DSR [32]1077.30
TET [6]1083.17
NDA [27]1081.70
Spikformer [57]1080.90
12886.60
MST (ours)25687.20
51288.12
N-CALTECH101Swin-T (BN)/92.00
SALT [19]2055.00
NDA [27]1083.70
6484.71
MST (ours)12889.42
25691.38
N-CARSSwin-T (BN)/97.14
CarSNN [48]1086.00
NDA [27]1091.90
3294.67
MST (ours)6496.58
12897.28
Action RecognitionSwin-T (BN)/90.14
STCA [12]1071.20
Mb-SNN [28]1078.10
6484.76
MST (ours)12886.92
25688.21
ASL-DVSSwin-T (BN)/99.90
Meta-SNN [45]10096.04
6498.04
MST (ours)12898.51
25699.10
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.621, + 0.892, + 0.649 + ], + "angle": 0, + "content": "Table 2. Performance comparison between the proposed model and the SOTA models on different neuromorphic datasets." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.667, + 0.892, + 0.759 + ], + "angle": 0, + "content": "to leverage pre-training weights from the ImageNet dataset, accelerating the training convergence. Data augmentation for SNNs [27] is also applied to improve the accuracy. The ensuing experimental results demonstrate that the proposed fine-tuning approach for ANN-to-SNN conversion achieves remarkably high accuracy." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.761, + 0.892, + 0.882 + ], + "angle": 0, + "content": "The experimental results presented in Tab. 2 demonstrate the effectiveness of the proposed MST model in processing neuromorphic datasets. We compare the MST model with several SOTA SNN models on five popular neuromorphic datasets, including CIFAR10-DVS, N-Caltech101, NCars, Action Recognition, and ASL-DVS dataset. The experimental results show that the MST model achieves the highest top-1 accuracy on all datasets." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.886, + 0.892, + 0.9 + ], + "angle": 0, + "content": "CIFAR10-DVS, N-Caltech101, and N-Cars datasets are" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.946, + 0.516, + 0.956 + ], + "angle": 0, + "content": "1766" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.288 + ], + "angle": 0, + "content": "constructed by converting the static datasets into event data by using event-based cameras. Tab. 2 shows that the MST model outperforms other SOTA SNN models significantly, achieving improvements of \\(4.95\\%\\), \\(7.68\\%\\), and \\(5.38\\%\\) on CIFAR10-DVS, N-Caltech101, and N-Cars, respectively. The Action Recognition dataset consists of a series of human actions captured by event-based cameras. By adopting the data preprocessing method of [20], our MST model achieves a top-1 accuracy of \\(88.21\\%\\), which is far higher than other models. Additionally, the ASL-DVS dataset is a large 24-class dataset of gestures and the experimental results demonstrate that our MST model outperforms other SOTA models by \\(3.06\\%\\)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.289, + 0.472, + 0.334 + ], + "angle": 0, + "content": "These results highlight the effectiveness of our proposed MST model in processing various types of neuromorphic datasets." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.346, + 0.471, + 0.378 + ], + "angle": 0, + "content": "4.3. Effectiveness of the Random Spike Masking Method" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.385, + 0.47, + 0.461 + ], + "angle": 0, + "content": "The ANN-to-SNN conversion method typically involves a large number of time steps, leading to high power consumption. To address this issue, we propose the RSM method for spike pruning, and we demonstrate its effectiveness in the following section." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.462, + 0.47, + 0.612 + ], + "angle": 0, + "content": "Drawing inspiration from knowledge distillation [16], we use the model without masked as a teacher model, and the model after masked as a student model. By fine-tuning the student model, the masked model achieves high performance comparable to the original model without masking in terms of accuracy. This finding highlights the efficacy of the knowledge distillation technique in training masked models without compromising their performance. Consequently, we employ the fine-tuning approach as the training method for our subsequent comparative analysis." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.613, + 0.47, + 0.718 + ], + "angle": 0, + "content": "We evaluate the RSM method in two critical modules in the Transformer: the self-attention (SA) module and the Multi-layer Perceptron (MLP) module. As shown in Fig. 2(d-e), we apply the RSM method to the Query, Key, and Attention matrices in the SA module, as well as the output spike matrix of the first fully connected layer within each block of the MLP module." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Fig. 5(a) and (b) depict the variation in accuracy for different masking ratios on the CIFAR-10 and CIFAR-100 datasets, respectively. The experimental results demonstrate that the accuracy decreases with the increasing masking ratio for both the SA and MLP modules, but their sensitivity to masking ratio changes differs. Specifically, the accuracy of the SA module remains stable over a certain range of masking ratios. In contrast, the accuracy of the MLP module declines more sharply and is more sensitive to masking ratio changes. Consistent with prior research [34, 49], the redundancy in the SA module enables the MST to withstand the losses caused by missing input spikes with" + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.091, + 0.692, + 0.236 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.509, + 0.236, + 0.692, + 0.375 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.699, + 0.091, + 0.885, + 0.236 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.709, + 0.236, + 0.885, + 0.375 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.389, + 0.895, + 0.459 + ], + "angle": 0, + "content": "Figure 5. The effectiveness of the RSM method in (a) SA and (b) MLP modules of the MST model, as well as in Spiking (c) ResNet-18 and (d) VGG-16 models, with varying masking ratios. The inset photographs show the standard deviation of accuracy in 10 runs." + }, + { + "type": "image", + "bbox": [ + 0.519, + 0.462, + 0.875, + 0.632 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.646, + 0.892, + 0.674 + ], + "angle": 0, + "content": "Figure 6. Comparison of the accuracy of masking different numbers of blocks on the CIFAR-100 dataset." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.686, + 0.892, + 0.716 + ], + "angle": 0, + "content": "out significantly affecting the overall performance of the SNN." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.718, + 0.892, + 0.854 + ], + "angle": 0, + "content": "In addition to the variation in sensitivity to changes in the masking ratio between different modules, our experiments also demonstrate that the sensitivity can vary depending on the dataset used. The CIFAR-10 dataset is relatively less sensitive to changes in the masking ratio, with only a \\(0.1\\%\\) decrease in accuracy when the masking ratio reaches \\(80\\%\\). In contrast, the CIFAR-100 dataset is more sensitive to changes in the masking ratio, experiencing a more substantial accuracy decline as the masking ratio increases." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.903 + ], + "angle": 0, + "content": "We also investigate the potential of the RSM method as a general approach for reducing power consumption in the context of ANN-to-SNN conversion. By applying the RSM" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "1767" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.08, + 0.091, + 0.483, + 0.26 + ], + "angle": 0, + "content": "
ModelRandom RatioP (α Watts)Accuracy (%)
MST0%3.9G (×1)97.27 (+0)
50%3.2G (×0.82)97.25 (-0.02)
75%2.9G (×0.74)97.29 (+0.02)
ResNet-180%58.2M (×1)96.48 (+0)
50%40.7M (×0.70)92.88 (-3.60)
75%34.1M (×0.58)82.68 (-13.80)
VGG-160%24.4M (×1)95.46 (+0)
50%18.9M (×0.77)89.56 (-5.90)
75%16.7M (×0.68)79.09 (-16.37)
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.076, + 0.269, + 0.47, + 0.339 + ], + "angle": 0, + "content": "Table 3. Comparison of power consumption and accuracy between models with a Masking ratio of \\(0\\%\\), \\(50\\%\\), and \\(75\\%\\) on the CIFAR-10 dataset, respectively. \\((\\dots)\\) in the table denotes the power consumption/accuracy compared to the unmasked model (with \\(0\\%\\) random ratio)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.353, + 0.47, + 0.489 + ], + "angle": 0, + "content": "method to other SNN models like Spiking ResNet-18 and VGG-16 and introducing a masking ratio to each convolution layer, we aim to decrease the transmitted spikes. Our results, presented in Fig. 5, demonstrate that the redundancy of these models can also be leveraged to maintain performance while reducing power consumption within a specific range. This indicates the potential of the RSM method for widespread applications in various SNN models for improving energy efficiency." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.49, + 0.47, + 0.625 + ], + "angle": 0, + "content": "Fig. 6 illustrates the impact of masking different numbers of blocks on the accuracy of the MST model. Our results indicate a non-linear, positive relationship between the number of masked blocks and performance loss. Notably, masking the first 2-5 blocks causes a slight performance loss, and the loss increases with more masked blocks until saturation at around 9-10 blocks. These observations provide valuable insights for designing partially masked blocks." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.626, + 0.47, + 0.716 + ], + "angle": 0, + "content": "To better evaluate the effects of the RSM method on energy consumption reduction, we utilize theoretical estimates of energy consumption on neuromorphic chips based on previous studies [4, 7]. Assuming that a spike activity consumes \\(\\alpha\\) Joules and 1 time step takes \\(1\\mathrm{ms}\\). Then the power model is defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.17, + 0.729, + 0.47, + 0.759 + ], + "angle": 0, + "content": "\\[\nP = \\frac {\\text {t o t a l s p i k e s}}{1 \\times 1 0 ^ {- 3}} \\times \\alpha (\\text {W a t t s}) \\tag {10}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Tab. 3 presents the power consumption and accuracy of the MST, ResNet-18, and VGG-16 at \\(0\\%\\), \\(50\\%\\), and \\(75\\%\\) masking ratios on the CIFAR-10 dataset. The RSM method is applied to the SA module in the MST and each block in ResNet-18 and VGG-16. The results demonstrate that the RSM method has a direct effect on the number of spikes transmitted, which in turn reduces power consumption. In specific, applying the RSM method to the MST" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.088, + 0.885, + 0.245 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.257, + 0.892, + 0.3 + ], + "angle": 0, + "content": "Figure 7. Comparison of attention maps between the MST model with \\(0\\%\\), \\(50\\%\\), and \\(75\\%\\) masking ratio (from top to bottom) with 5 different time steps." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.314, + 0.892, + 0.451 + ], + "angle": 0, + "content": "model can reduce power consumption by \\(26.8\\%\\) without any loss in performance when the masking ratio reaches \\(75\\%\\). This finding suggests that there exist substantial redundant spikes in the SA module that can be pruned for better energy efficiency. As for ResNet-18 and VGG-16, the RSM method also yields significant power reduction. For instance, ResNet-18 can reduce power consumption by \\(30.1\\%\\) with a moderate accuracy loss of \\(3.6\\%\\). However, excessive masking leads to a significant drop in accuracy." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.452, + 0.892, + 0.555 + ], + "angle": 0, + "content": "In summary, our results demonstrate that the proposed RSM method is effective when applied to the SA module in the Transformer, as well as other SNN models. By eliminating redundant spikes, the RSM method reduces power consumption while preserving performance, making it a promising approach for energy-efficient ANN-to-SNN conversion." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.558, + 0.892, + 0.724 + ], + "angle": 0, + "content": "To visualize the impact of different masking ratios on attention maps, we compared the models with \\(0\\%\\), \\(50\\%\\), and \\(75\\%\\) masking ratios using the Spike Activation Maps (SAM) method. The results, shown in Fig. 7, demonstrate that the models with different masking ratios concentrate on similar areas of the object at the same time step, with the red parts outlining the object. Comparison with the ANN model using the ScoreCAM method [50] reveals that both models focus on similar key information. These results suggest that the proposed RSM method preserves the regions of interest within the model, contributing to accuracy preservation." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.739, + 0.614, + 0.754 + ], + "angle": 0, + "content": "5. Discussion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.892, + 0.841 + ], + "angle": 0, + "content": "In this paper, we proposed the Masked Spiking Transformer (MST) with the Random Spike Masking (RSM) method. By pruning input spikes, the proposed RSM method effectively reduces power consumption while maintaining the performance of the model within a certain range." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.841, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Though our experiments highlight the superiority of the MST model over state-of-the-art SNN models, our model still has limitations that need addressing. A key constraint is the relatively long time steps needed by the ANN-to-SNN" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "1768" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.121 + ], + "angle": 0, + "content": "conversion method, limiting the suitability of the proposed model for real-time applications with strict timing demands." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.123, + 0.471, + 0.304 + ], + "angle": 0, + "content": "Furthermore, even though the RSM method reduces the number of spikes and energy consumption, the experiment in this article merely investigates its applicability of ANN-to-SNN conversion, thus exhibiting relatively high energy consumption compared to direct-trained SNN models, which take fewer time steps. Consequently, future research could apply the RSM method to direct training methods to optimize energy consumption further and make SNNs more practical for real-world applications. Additionally, adopting different masking ratios across layers may achieve a better balance between performance and energy efficiency." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.32, + 0.196, + 0.336 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.345, + 0.471, + 0.556 + ], + "angle": 0, + "content": "In this work, we propose a Masked Spiking Transformer (MST) framework that combines the energy efficiency of SNNs with the high-performance self-attention mechanism of Transformers using the ANN-to-SNN method. Additionally, we introduce a Random Spike Masking (RSM) method to prune input spikes, thus reducing power consumption. The experimental results demonstrate that the MST model outperforms current SOTA SNN models on both static and neuromorphic datasets. Furthermore, the proposed RSM method shows significant power reduction while maintaining performance in different modules of the Transformer and other SNN models. Our work opens up new possibilities for developing high-performance SNN models, paving the way for future research in this area." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.572, + 0.258, + 0.59 + ], + "angle": 0, + "content": "7. Acknowledgement" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.598, + 0.47, + 0.72 + ], + "angle": 0, + "content": "This work is supported by the Guangzhou-HKUST(GZ) Joint Funding Program (Grant No. 2023A03J0682), HK RGC (Grant Nos. 27206321, 17205922, 17212923), NSFC (Grant No. 62122004), National Key R&D Program of China (Grant No. SQ2022YFB3600159). This research is also partially supported by ACCESS - AI Chip Center for Emerging Smart Systems, sponsored by Innovation and Technology Fund (ITF), Hong Kong SAR." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.735, + 0.175, + 0.751 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.085, + 0.76, + 0.47, + 0.829 + ], + "angle": 0, + "content": "[1] Yin Bi, Aaron Chadha, Alhabib Abbas, Eirina Bourtsovatze, and Yiannis Andreopoulos. Graph-based object classification for neuromorphic vision sensing. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 491-501, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.831, + 0.47, + 0.9 + ], + "angle": 0, + "content": "[2] Tong Bu, Wei Fang, Jianhao Ding, PengLin Dai, Zhaofei Yu, and Tiejun Huang. Optimal ANN-SNN Conversion for High-accuracy and Ultra-low-latency Spiking Neural Networks. In International Conference on Learning Representations, 2021." + }, + { + "type": "list", + "bbox": [ + 0.085, + 0.76, + 0.47, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "[3] Yongqiang Cao, Yang Chen, and Deepak Khosla. Spiking deep convolutional neural networks for energy-efficient object recognition. International Journal of Computer Vision, 113(1):54-66, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.149, + 0.894, + 0.205 + ], + "angle": 0, + "content": "[4] Yongqiang Cao, Yang Chen, and Deepak Khosla. Spiking deep convolutional neural networks for energy-efficient object recognition. International Journal of Computer Vision, 113:54-66, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.207, + 0.895, + 0.262 + ], + "angle": 0, + "content": "[5] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In 2009 IEEE Conference on Computer Vision and Pattern Recognition, pages 248–255. IEEE, 2009." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.264, + 0.895, + 0.317 + ], + "angle": 0, + "content": "[6] Shikuang Deng, Yuhang Li, Shanghai Zhang, and Shi Gu. Temporal Efficient Training of Spiking Neural Network via Gradient Re-weighting. arXiv preprint arXiv:2202.11946, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.321, + 0.895, + 0.375 + ], + "angle": 0, + "content": "[7] Jianhao Ding, Zhaofei Yu, Yonghong Tian, and Tiejun Huang. Optimal ann-snn conversion for fast and accurate inference in deep spiking neural networks. arXiv preprint arXiv:2105.11654, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.377, + 0.892, + 0.46 + ], + "angle": 0, + "content": "[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, and Sylvain Gelly. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.462, + 0.892, + 0.531 + ], + "angle": 0, + "content": "[9] Wei Fang, Yanqi Chen, Jianhao Ding, Ding Chen, Zhaofei Yu, Huihui Zhou, Timothée Masquelier, Yonghong Tian, and other contributors. Spikingjelly. https://github.com/fangwei123456/spikingjelly, 2020. Accessed: 2023-02-21." + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.533, + 0.892, + 0.589 + ], + "angle": 0, + "content": "[10] Wei Fang, Zhaofei Yu, Yanqi Chen, Tiejun Huang, Timothee Masquelier, and Yonghong Tian. Deep residual learning in spiking neural networks. Advances in Neural Information Processing Systems, 34:21056-21069, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.591, + 0.892, + 0.66 + ], + "angle": 0, + "content": "[11] Wei Fang, Zhaofei Yu, Yanqi Chen, Timothée Masquelier, Tiejun Huang, and Yonghong Tian. Incorporating learnable membrane time constant to enhance learning of spiking neural networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2661-2671, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.661, + 0.892, + 0.758 + ], + "angle": 0, + "content": "[12] Pengjie Gu, Rong Xiao, Gang Pan, and Huajin Tang. STCA: Spatio-Temporal Credit Assignment with Delayed Feedback in Deep Spiking Neural Networks. In Proceedings of the Twenty-Eighth International Joint Conference on Artificial Intelligence, pages 1366-1372, Macao, China, Aug. 2019. International Joint Conferences on Artificial Intelligence Organization." + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.76, + 0.892, + 0.842 + ], + "angle": 0, + "content": "[13] Bing Han, Gopalakrishnan Srinivasan, and Kaushik Roy. Rmp-snn: Residual membrane potential neuron for enabling deeper high-accuracy and low-latency spiking neural network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13558–13567, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.502, + 0.845, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[14] Ali Hassani, Steven Walton, Nikhil Shah, Abulikemu Abuduweili, Jiachen Li, and Humphrey Shi. Escaping the big data paradigm with compact transformers. arXiv preprint arXiv:2104.05704, 2021." + }, + { + "type": "list", + "bbox": [ + 0.502, + 0.093, + 0.895, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "1769" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.149, + 0.47, + 0.176 + ], + "angle": 0, + "content": "[16] Geoffrey Hinton, Oriol Vinyals, and Jeff Dean. Distilling the Knowledge in a Neural Network, Mar. 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.179, + 0.469, + 0.219 + ], + "angle": 0, + "content": "[17] Eugene M. Izhikevich. Simple model of spiking neurons. IEEE Transactions on neural networks, 14(6):1569-1572, 2003." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.222, + 0.469, + 0.262 + ], + "angle": 0, + "content": "[18] Youngeun Kim and Priyadarshini Panda. Optimizing deeper spiking neural networks for dynamic vision sensing. Neural Networks, 144:686-698, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.265, + 0.469, + 0.305 + ], + "angle": 0, + "content": "[19] Youngeun Kim and Priyadarshini Panda. Optimizing deeper spiking neural networks for dynamic vision sensing. Neural Networks, 144:686-698, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.308, + 0.469, + 0.389 + ], + "angle": 0, + "content": "[20] Karthik Sivarama Krishnan and Koushik Sivarama Krishnan. Benchmarking Conventional Vision Models on Neuromorphic Fall Detection and Action Recognition Dataset. In 2022 IEEE 12th Annual Computing and Communication Workshop and Conference (CCWC), pages 0518-0523. IEEE, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.392, + 0.469, + 0.419 + ], + "angle": 0, + "content": "[21] Alex Krizhevsky and Geoffrey Hinton. Learning multiple layers of features from tiny images. 2009." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.421, + 0.469, + 0.462 + ], + "angle": 0, + "content": "[22] Y. Lecun, L. Bottou, Y. Bengio, and P. Haffner. Gradient-based learning applied to document recognition. Proceedings of the IEEE, 86(11):2278-2324, Nov. 1998." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.464, + 0.469, + 0.504 + ], + "angle": 0, + "content": "[23] William B. Levy and Robert A. Baxter. Energy-Efficient Neuronal Computation via Quantal Synaptic Failures. Journal of Neuroscience, 22(11):4746-4755, June 2002." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.507, + 0.469, + 0.548 + ], + "angle": 0, + "content": "[24] Hongmin Li, Hanchao Liu, Xiangyang Ji, Guoqi Li, and Luping Shi. CIFAR10-DVS: An Event-Stream Dataset for Object Classification. Frontiers in Neuroscience, 11, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.55, + 0.469, + 0.605 + ], + "angle": 0, + "content": "[25] Yuhang Li, Shikuang Deng, Xin Dong, Ruihao Gong, and Shi Gu. A free lunch from ANN: Towards efficient, accurate spiking neural networks calibration. In International Conference on Machine Learning, pages 6316-6325. PMLR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.607, + 0.469, + 0.674 + ], + "angle": 0, + "content": "[26] Yuhang Li, Yufei Guo, Shanghang Zhang, Shikuang Deng, Yongqing Hai, and Shi Gu. Differentiable spike: Rethinking gradient-descent for training spiking neural networks. Advances in Neural Information Processing Systems, 34:23426-23439, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.677, + 0.469, + 0.731 + ], + "angle": 0, + "content": "[27] Yuhang Li, Youngeun Kim, Hyoungseob Park, Tamar Geller, and Priyadarshini Panda. Neuromorphic Data Augmentation for Training Spiking Neural Networks. arXiv preprint arXiv:2203.06145, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.734, + 0.469, + 0.829 + ], + "angle": 0, + "content": "[28] Qianhui Liu, Dong Xing, Huajin Tang, De Ma, and Gang Pan. Event-based Action Recognition Using Motion Information and Spiking Neural Networks. In Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence, pages 1743-1749, Montreal, Canada, Aug. 2021. International Joint Conferences on Artificial Intelligence Organization." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.832, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[29] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10012-10022, 2021." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[30] Wolfgang Maass. Networks of spiking neurons: The third generation of neural network models. Neural networks, 10(9):1659-1671, 1997." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.137, + 0.894, + 0.176 + ], + "angle": 0, + "content": "[31] Warren S. McCulloch and Walter Pitts. A logical calculus of the ideas immanent in nervous activity. The bulletin of mathematical biophysics, 5(4):115-133, 1943." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.179, + 0.894, + 0.261 + ], + "angle": 0, + "content": "[32] Qingyan Meng, Mingqing Xiao, Shen Yan, Yisen Wang, Zhouchen Lin, and Zhi-Quan Luo. Training High-Performance Low-Latency Spiking Neural Networks by Differentiation on Spike Representation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12444–12453, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.264, + 0.892, + 0.318 + ], + "angle": 0, + "content": "[33] Shu Miao, Guang Chen, Xiangyu Ning, Yang Zi, Kejia Ren, Zhenshan Bing, and Alois Knoll. Neuromorphic vision datasets for pedestrian detection, action recognition, and fall detection. Frontiers in neurorobotics, 13:38, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.321, + 0.892, + 0.361 + ], + "angle": 0, + "content": "[34] Paul Michel, Omer Levy, and Graham Neubig. Are sixteen heads really better than one? Advances in neural information processing systems, 32, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.364, + 0.892, + 0.432 + ], + "angle": 0, + "content": "[35] Etienne Mueller, Viktor Studenyak, Daniel Auge, and Alois Knoll. Spiking Transformer Networks: A Rate Coded Approach for Processing Sequential Data. In 2021 7th International Conference on Systems and Informatics (ICSAI), pages 1-5, Nov. 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.435, + 0.892, + 0.502 + ], + "angle": 0, + "content": "[36] Emre O. Neftci, Hesham Mostafa, and Friedemann Zenke. Surrogate Gradient Learning in Spiking Neural Networks: Bringing the Power of Gradient-Based Optimization to Spiking Neural Networks. IEEE Signal Processing Magazine, 36(6):51-63, Nov. 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.504, + 0.892, + 0.559 + ], + "angle": 0, + "content": "[37] Garrick Orchard, Ajinkya Jayawant, Gregory K. Cohen, and Nitish Thakor. Converting Static Image Datasets to Spiking Neuromorphic Datasets Using Saccades. Frontiers in Neuroscience, 9, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.562, + 0.892, + 0.617 + ], + "angle": 0, + "content": "[38] Wachirawit Ponghiran and Kaushik Roy. Spiking neural networks with improved inherent recurrence dynamics for sequential learning. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 8001-8008, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.62, + 0.892, + 0.659 + ], + "angle": 0, + "content": "[39] Nitin Rathi and Kaushik Roy. DIET-SNN: Direct Input Encoding With Leakage and Threshold Optimization in Deep Spiking Neural Networks, Dec. 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.662, + 0.892, + 0.716 + ], + "angle": 0, + "content": "[40] Nitin Rathi, Gopalakrishnan Srinivasan, Priyadarshini Panda, and Kaushik Roy. Enabling deep spiking neural networks with hybrid conversion and spike timing dependent backpropagation. arXiv preprint arXiv:2005.01807, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.719, + 0.892, + 0.786 + ], + "angle": 0, + "content": "[41] Bodo Rueckauer, Iulia-Alexandra Lungu, Yuhuang Hu, Michael Pfeiffer, and Shih-Chii Liu. Conversion of continuous-valued deep networks to efficient event-driven networks for image classification. Frontiers in neuroscience, 11:682, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.789, + 0.892, + 0.829 + ], + "angle": 0, + "content": "[42] Karen Simonyan and Andrew Zisserman. Very Deep Convolutional Networks for Large-Scale Image Recognition, Apr. 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.832, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[43] Amos Sironi, Manuele Brambilla, Nicolas Bourdis, Xavier Lagorce, and Ryad Benosman. HATS: Histograms of Averaged Time Surfaces for Robust Event-Based Object Classification. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1731-1740, 2018." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.946, + 0.516, + 0.956 + ], + "angle": 0, + "content": "1770" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[44] Nitish Srivastava, Geoffrey Hinton, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. Dropout: A simple way to prevent neural networks from overfitting. The journal of machine learning research, 15(1):1929-1958, 2014." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.149, + 0.468, + 0.189 + ], + "angle": 0, + "content": "[45] Kenneth M. Stewart and Emre O. Neftci. Meta-learning spiking neural networks with surrogate gradient descent. Neuro-morphic Computing and Engineering, 2(4):044002, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.191, + 0.468, + 0.244 + ], + "angle": 0, + "content": "[46] Christoph Stöckl and Wolfgang Maass. Optimized spiking neurons can classify images with high accuracy through temporal coding with two spikes. Nature Machine Intelligence, 3(3):230-238, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.247, + 0.468, + 0.301 + ], + "angle": 0, + "content": "[47] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, \\(\\backslash\\) Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.303, + 0.468, + 0.383 + ], + "angle": 0, + "content": "[48] Alberto Viale, Alberto Marchisio, Maurizio Martina, Guido Masera, and Muhammad Shafique. Carsnn: An efficient spiking neural network for event-based autonomous cars on the loihi neuromorphic research processor. In 2021 International Joint Conference on Neural Networks (IJCNN), pages 1-10. IEEE, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.386, + 0.468, + 0.44 + ], + "angle": 0, + "content": "[49] Elena Voita, David Talbot, Fedor Moiseev, Rico Sennrich, and Ivan Titov. Analyzing multi-head self-attention: Specialized heads do the heavy lifting, the rest can be pruned. arXiv preprint arXiv:1905.09418, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.442, + 0.468, + 0.524 + ], + "angle": 0, + "content": "[50] Haofan Wang, Zifan Wang, Mengnan Du, Fan Yang, Zijian Zhang, Sirui Ding, Piotr Mardziel, and Xia Hu. Score-CAM: Score-Weighted Visual Explanations for Convolutional Neural Networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops, pages 24–25, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.526, + 0.468, + 0.579 + ], + "angle": 0, + "content": "[51] Zheyu Yang, Yujie Wu, Guanrui Wang, Yukuan Yang, Guoqi Li, Lei Deng, Jun Zhu, and Luping Shi. DashNet: A hybrid artificial and spiking neural network for high-speed object tracking. arXiv preprint arXiv:1909.12942, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.581, + 0.468, + 0.649 + ], + "angle": 0, + "content": "[52] Man Yao, Huanhuan Gao, Guangshe Zhao, Dingheng Wang, Yihan Lin, Zhaoxu Yang, and Guoqi Li. Temporal-wise attention spiking neural networks for event streams classification. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10221-10230, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.651, + 0.468, + 0.704 + ], + "angle": 0, + "content": "[53] Zhuliang Yao, Yue Cao, Yutong Lin, Ze Liu, Zheng Zhang, and Han Hu. Leveraging batch normalization for vision transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 413-422, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.707, + 0.468, + 0.774 + ], + "angle": 0, + "content": "[54] Jiqing Zhang, Bo Dong, Haiwei Zhang, Jianchuan Ding, Felix Heide, Baocai Yin, and Xin Yang. Spiking Transformers for Event-Based Single Object Tracking. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8801-8810, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.776, + 0.468, + 0.844 + ], + "angle": 0, + "content": "[55] Jiyuan Zhang, Lulu Tang, Zhaofei Yu, Jiwen Lu, and Tiejun Huang. Spike Transformer: Monocular Depth Estimation for Spiking Camera. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part VII, pages 34-52. Springer, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.847, + 0.468, + 0.9 + ], + "angle": 0, + "content": "[56] Hanle Zheng, Yujie Wu, Lei Deng, Yifan Hu, and Guoqi Li. Going deeper with directly-trained larger spiking neural networks. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 11062-11070, 2021." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "[57] Zhaokun Zhou, Yuesheng Zhu, Chao He, Yaowei Wang, Shuicheng Yan, Yonghong Tian, and Li Yuan. Spikformer: When Spiking Neural Network Meets Transformer. arXiv preprint arXiv:2209.15425, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.149, + 0.892, + 0.189 + ], + "angle": 0, + "content": "[58] Michael Zhu and Suyog Gupta. To prune, or not to prune: Exploring the efficacy of pruning for model compression, Nov. 2017." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.189 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.946, + 0.514, + 0.956 + ], + "angle": 0, + "content": "1771" + } + ] +] \ No newline at end of file diff --git a/2023/Masked Spiking Transformer/7ef4a39e-394a-4406-bcd4-3ff4096115d4_origin.pdf b/2023/Masked Spiking Transformer/7ef4a39e-394a-4406-bcd4-3ff4096115d4_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..e9e8bec8c48e89e37b754ab882759adc96b9ba9b --- /dev/null +++ b/2023/Masked Spiking Transformer/7ef4a39e-394a-4406-bcd4-3ff4096115d4_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:a98242b1b52c03de3ff9c721e5de607c4054508a84bc54adb169d2da9e32748e +size 5765052 diff --git a/2023/Masked Spiking Transformer/full.md b/2023/Masked Spiking Transformer/full.md new file mode 100644 index 0000000000000000000000000000000000000000..7cb600c82d3e8c047c524bdb0c484393b846cdbf --- /dev/null +++ b/2023/Masked Spiking Transformer/full.md @@ -0,0 +1,343 @@ +# Masked Spiking Transformer + +Ziqing Wang $^{1,2*}$ Yuetong Fang $^{1*}$ Jiahang Cao $^{1}$ Qiang Zhang $^{1}$ Zhongrui Wang $^{3,4\dagger}$ Renjing Xu $^{1\dagger}$ + +1The Hong Kong University of Science and Technology (Guangzhou) 2North Carolina State University + +3The University of Hong Kong 4ACCESS - AI Chip Center for Emerging Smart Systems + +zwang247@ncsu.edu, {yfang870, jcao248, qzhang749}@connect.hkust-gz.edu.cn + +zrwang@eee.hku.hk, renjingxu@ust.hk + +# Abstract + +The combination of Spiking Neural Networks (SNNs) and Transformers has attracted significant attention due to their potential for high energy efficiency and high-performance nature. However, existing works on this topic typically rely on direct training, which can lead to suboptimal performance. To address this issue, we propose to leverage the benefits of the ANN-to-SNN conversion method to combine SNNs and Transformers, resulting in significantly improved performance over existing state-of-the-art SNN models. Furthermore, inspired by the quantal synaptic failures observed in the nervous system, which reduce the number of spikes transmitted across synapses, we introduce a novel Masked Spiking Transformer (MST) framework. This incorporates a Random Spike Masking (RSM) method to prune redundant spikes and reduce energy consumption without sacrificing performance. Our experimental results demonstrate that the proposed MST model achieves a significant reduction of $26.8\%$ in power consumption when the masking ratio is $75\%$ while maintaining the same level of performance as the unmasked model. The code is available at: https://github.com/bic-L/Masked-Spiking-Transformer. + +# 1. Introduction + +Spiking neural networks (SNNs), considered as the next generation neural networks [30], are brain-inspired neural networks based on the dynamic characteristics of biological neurons [31, 17]. SNNs have attracted significant attention due to their unique properties in handling sparse data, which can yield great energy efficiency benefits on neuromorphic hardware. Due to their specialties, they have been widely + +![](images/f1c7ed3952b75e5d050a894adccea07a6265f2ddd01dcdb238d5d7ee6dcaa56e.jpg) +Figure 1. Performance of MST and other SOTA SNN models regarding top-1 accuracy and time steps. The markers, represented by circles and star shapes, denote the direct training (DT) and the ANN-to-SNN (A2S) conversion method, respectively, where the marker size corresponds to the model size. Results show that the proposed MST model achieves higher accuracy than the other SNN models. + +![](images/df80e8530cbd60dd165de468d9a4cd683e6048d0e4ca1ca9b356d83b5b4d7d05.jpg) + +utilized in various fields, such as classification [32, 18], object detection [3] and tracking [51], etc. Nevertheless, SNNs currently can hardly realize a comparable performance to that of artificial neural networks (ANNs), especially for complex tasks such as ImageNet [40]. + +In order to improve the performance of SNNs, various training methods have been proposed, broadly categorized as the direct training method and the ANN-to-SNN conversion method. Direct training methods leverage a continuous relaxation of the non-smooth spiking mechanism to enable backpropagation with a surrogate gradient function for handling non-differentiability [36], but this can lead to unstable gradient propagation and relatively low accuracy + +compared to leading ANNs [38]. Alternatively, ANN-to-SNN conversion methods convert pre-trained ANNs into SNNs for better performance while requiring more time steps, with increased power consumption to reduce conversion errors [46, 25, 2, 7]. Our focus is on implementing the ANN-to-SNN conversion method to narrow the performance gap between leading ANNs and SNNs, but the required long time steps pose challenges in reducing energy consumption. Therefore, identifying strategies to decrease power consumption while maintaining excellent performance is crucial. + +The biological nervous system offers valuable insights for addressing the challenges of implementing high-performance Spiking Transformers using the ANN-to-SNN conversion method. The quantal synaptic failure theory suggests that missing information during neuronal signal transmission may not impact the computational information transmitted to a postsynaptic neuron under certain conditions, but can reduce energy consumption and heat production [23]. Likewise, in the ANN-to-SNN conversion process, missing spikes can possibly be compensated for by leveraging the correlations between signals in the space and time domains during the information propagation over multiple time steps. In addition, neural network models possess lots of redundant connections: prior works reveal that the redundancy in the self-attention module of Transformers can be pruned without significantly impacting performance [34, 49]. Therefore, eliminating redundant information during the transmission of neuronal signals can possibly reduce overall energy consumption in the Spiking Transformer model while preserving high performance. + +In our work, we propose a Masked Spiking Transformer (MST), which incorporates a Random Spike Masking (RSM) method designed specifically for SNNs. The RSM method randomly selects only a subset of input spikes, significantly reducing the number of spikes involved in the computation process. We evaluate the MST model on both static and neuromorphic datasets, demonstrating its superiority over existing SNN models. Our experiments show that the RSM method can reduce energy consumption on the self-attention module and the MLP module in Transformer, enabling the SNNs to take advantage of energy efficiency and high performance. Furthermore, the proposed RSM method is not limited to Transformer, but can be extended to other backbones such as ResNet and VGG, highlighting its potential as a general technique to improve SNN efficiency. Our results demonstrate the potential of this approach to provide a new direction for developing high-performance and energy-efficient SNN models. + +The main contributions of this paper can be summarized as follows: + +- We propose a Masked Spiking Transformer (MST) using the ANN-to-SNN conversion method. To the best + +![](images/3f36b6897dc51e05c932bfa271512da956a15bc4fd01b24b1f0e6b13e8659968.jpg) +Figure 2. Overview of our MST. (a) Schematic of the model architecture of the Swin Transformer, which is the backbone of our model. (b) Schematic of the proposed Transformer blocks, where BN layers replace the original LN layers. (c) Conceptual illustration of the RSM method, which involves randomly masking the input spike. (d-e) The RSM method in self-attention and MLP module. + +of our knowledge, it is the first exploration of applying the self-attention mechanism fully in SNNs utilizing the ANN-to-SNN conversion method. + +- The MST model is evaluated on both static and neuromorphic datasets, and the results show that it outperforms state-of-the-art (SOTA) SNNs on all datasets. In specific, the top-1 accuracy of the MST model is $1.21\%$ , $7.3\%$ , and $3.7\%$ higher than the current SOTA SNN model on the CIFAR-10, CIFAR-100, and ImageNet datasets, respectively. +- We design a Random Spike Masking (RSM) method for SNNs trained with the ANN-to-SNN conversion method to prune the redundant spikes during inference and save energy consumption. +- Extensive experiments show that our proposed RSM is a versatile and general method that can be utilized in other spike-based deep networks, such as ResNet and VGG SNN model variants. + +# 2. Related Work + +Spiking Neural Networks SNNs have gained popularity in the field of brain-inspired intelligence due to their compatibility with neuromorphic hardware and biological properties. With the increasing interest in larger-scale and higher-performance SNNs, recent research has focused on developing novel training algorithms and architectures. + +Zheng et al. proposed a threshold-dependent batch normalization (tdBN) method based on spatiotemporal backpropagation to train a large-scale SNN model with 50 layers [56]. Besides, Fang et al. proposed the SEW ResNet architecture for residual learning in deep SNNs to overcome the gradient vanishing problem [10]. Later, they introduced a training algorithm that learns the threshold of each spiking neuron to improve the performance of SNNs [11]. However, these methods mainly discuss the SNN models that are dominated by convolutional layers, such as the SNN variants of VGG [42] and ResNet [15]. Despite their improvements, the performance of these methods still struggles to match their ANN counterparts, limiting the application of SNNs. In this context, our proposed work focuses on implementing the self-attention mechanism in SNNs to design a Spiking Transformer that improves the performance of SNNs. + +Transformer Transformer [47] was first introduced in Natural Language Processing (NLP) and quickly gained popularity for its remarkable capabilities in capturing long-range dependencies. Its success in NLP has inspired researchers to explore its potential in computer vision. Vision Transformer (ViT) [8] was the first attempt to apply the Transformer to image classification. ViT has achieved impressive results on various computer vision benchmarks, demonstrating the effectiveness of the self-attention mechanism in image understanding. Following the success of ViT, a series of works [29, 14] proposed improvements to the original ViT architecture. Motivated by the success of Transformers and its variations, this paper proposes a new architecture for SNNs that leverages the capacities of the Transformer and the energy efficiency of SNNs. + +Spiking Transformer The combination of the Transformer and SNNs can achieve better performance, which has been discussed in prior studies, including STNet [54] and Spike-T [55]. These models utilized separate branches of SNNs and Transformers for feature extraction, leading to the inability to run independently on neuromorphic hardware and failing to exploit the energy efficiency benefits of SNNs fully. In addition, Mueller et al. [35] proposed a Spiking Transformer using the ANN-to-SNN conversion method, but they did not implement the self-attention module in SNNs. The recently proposed Spikformer [57] directly trained the Transformer in SNNs, but still struggles to achieve comparable performance to leading ANNs. To address these limitations, we apply the self-attention mechanism fully in SNNs by utilizing the ANN-to-SNN conversion method and propose the RSM method to improve both the performance and energy efficiency of the Spiking Transformer. Our model offers a new direction for developing high-performance SNNs using the ANN-to-SNN conversion method. + +# 3. Methods + +# 3.1. Spiking Neuron Model + +For ANNs, the input $\pmb{a}^{l-1}$ to layer $l$ is mapped to the output $\pmb{a}^l$ by a linear transformation matrix $\pmb{W}^l$ and a nonlinear activation function $f(\cdot)$ , that is $(l = 1,2,3,\dots,L)$ : + +$$ +\boldsymbol {a} ^ {l} = f \left(\boldsymbol {W} ^ {l} \boldsymbol {a} ^ {l - 1}\right) \tag {1} +$$ + +where $f(\cdot)$ is often set as the ReLU activation function. + +In SNNs, the Integrate-and-Fire (IF) spiking neuron model is commonly used in ANN-to-SNN conversion [25, 2, 7]. The dynamics of the IF model are described by: + +$$ +\pmb {v} ^ {l} (t) = \pmb {v} ^ {l} (t - 1) + \pmb {W} ^ {l} \theta^ {l - 1} \pmb {s} ^ {l - 1} (t) - \theta^ {l} \pmb {s} ^ {l} (t) \quad (2) +$$ + +where $\pmb{v}^l (t)$ denotes the membrane potential of neurons in layer $l$ at time step $t$ , which corresponds to the linear transformation matrix $\pmb{W}^{l}$ , the threshold $\theta^l$ , and the binary output spikes of neurons in the previous layer $l - 1$ , denoted as $\pmb{s}^{l - 1}(t)$ . The $s^l (t)$ is defined as follows: + +$$ +\boldsymbol {s} ^ {l} (t) = H \left(\boldsymbol {u} ^ {l} (t) - \theta^ {l}\right) \tag {3} +$$ + +where $\pmb{u}^{l}(t) = \pmb{v}^{l}(t - 1) + \pmb{W}^{l}\theta^{l - 1}\pmb{s}^{l - 1}(t)$ denotes the membrane potential of neurons before the trigger of a spike at time step $t$ , $H(\cdot)$ denotes the Heaviside step function. The neurons generate output spikes whenever the membrane potential $\pmb{u}^{l}(t)$ exceeds the threshold value $\theta^l$ , and the membrane potential is reset by subtracting the threshold value to reduce information loss [41]. + +# 3.2.ANN-to-SNN conversion + +To achieve the ANN-SNN conversion, a relationship is established between the rectified linear unit (ReLU) activation of analog neurons in ANNs and the firing rate or postsynaptic potential of spiking neurons in SNNs. This is obtained by summing Eq. 2 from time step 1 to $T$ dividing $T$ on both sides, resulting in the following equation: + +$$ +\frac {\boldsymbol {v} ^ {l} (T) - \boldsymbol {v} ^ {l} (0)}{T} = \frac {\sum_ {t = 1} ^ {T} \boldsymbol {W} ^ {l} \theta^ {l - 1} \boldsymbol {s} ^ {l - 1} (t)}{T} - \frac {\sum_ {t = 1} ^ {T} \theta^ {l} \boldsymbol {s} ^ {l} (t)}{T} \tag {4} +$$ + +The linear relationship between $\phi^l (T)$ and $\phi^{l - 1}(T)$ is established by defining $\phi^l (T) = \frac{\sum_{t\equiv 1}^T\theta^l s^l(t)}{T}$ as the average postsynaptic potential: + +$$ +\phi^ {l} (T) = \boldsymbol {W} ^ {l} \phi^ {l - 1} (T) - \frac {\boldsymbol {v} ^ {l} (T) - \boldsymbol {v} ^ {l} (0)}{T} \tag {5} +$$ + +The equivalence between Eq. 1 and 5 holds only as $\mathrm{T}$ goes to infinity, resulting in a conversion error. To address this issue, we replace the ReLU activation function with the quantization clip-floor-shift (QCFS) [2] function in the ANNs. + +# 3.3. Model Architecture + +An overview of the MST is depicted in Fig. 2, where the Swin Transformer [29] is adopted as the backbone network. To convert the original network into a fully-spiking manner, we incorporate the QCFS activation functions after each linear or regularization layer during the training phase, which are replaced with Integrate-and-Fire (IF) neurons in the inference process, resulting in more efficient computation. + +The entire computation process in the spiking self-attention module can be formulated as: + +$$ +Q _ {s p k} [ t ] = \operatorname {I F} (X [ t ] * W _ {q}) \tag {6} +$$ + +$$ +K _ {s p k} [ t ] = \operatorname {I F} (X [ t ] * W _ {k}) +$$ + +where $Q_{spk}$ , $K_{spk}$ denote the spike matrices of the query and key at $t$ time step, $\mathrm{IF}(\cdot)$ is the IF neuron function, $W_{q}$ , $W_{k}$ denote the corresponding weight matrices. Attention score is defined as: + +$$ +A _ {s p k} [ t ] = \operatorname {I F} \left(\frac {Q _ {s p k} [ t ] * K _ {s p k} ^ {T} [ t ]}{\sqrt {d}}\right) \tag {7} +$$ + +where $A_{spk}$ represents the spike matrix of the attention score calculated by the dot product of the query spike matrix and the key spike matrix, and $d$ is a scaling factor equal to the feature dimension of a given attention head. + +The calculation of LN and BN can be expressed by: + +$$ +y = \frac {x - \operatorname {E} [ x ]}{\sqrt {\operatorname {V a r} [ x ] + \epsilon}} * \gamma + \beta \tag {8} +$$ + +where $x$ denotes the input tensor to be normalized, $\operatorname{E}[x]$ and $\operatorname{Var}[x]$ represent the mean and variance of $x$ , $\epsilon$ is a small constant added to the variance for numerical stability, $\gamma$ and $\beta$ are trainable scaling and bias parameters respectively, and $y$ is the normalized output of the layer. + +In LN, the mean and variance are calculated across the features of each sample in a batch. Therefore, each sample in the batch has its normalization parameters. On the other hand, BN calculates the mean and variance across all samples in a batch for each feature, which means the normalization parameters are shared across all samples in a batch. + +Normalization is important for ensuring the feasibility of ANN-to-SNN conversion. As illustrated in Fig. 3, different normalization approach results in vastly different membrane potential in the inference process. Normalizing along the channel dimension (LN) cause a distribution mismatch between ANN and SNN, which leads to performance degradation, while normalizing along the batch dimension (BN) preserves a similar result. Replace all LN layers with BN layers is a straightforward approach to normalize the post-activation distribution of ANNs during the conversion process, but for large datasets like ImageNet, there are convergence issues. We resolve this problem by simply adding + +![](images/a576c5b44bc04911a17c4c203092f13c8b8f878f5651da5977efa40b9de7a87c.jpg) +(a) ANN + +![](images/b2ecc446fa9bf249c908ea65e9e95e622ec7ef559cc58188a2d15b59bdc0849f.jpg) +(b) SNN (BN) + +![](images/c99baa9b30e33ed9725b32faf7db4c5e59e8340b2b9906af866793d3ee425de7.jpg) +(b) SNN (LN) +Figure 3. Illustration of distributions of (a) post-activation distribution in ANN, and (b-c) cumulative membrane potential distributions of SNN model with BN and LN, respectively. The heatmap shows a similar distribution between ANN and SNN(BN) models, while the widely varying distribution between ANN and SNN(LN) models leads to performance degradation. + +a BN layer after each linear layer in the MLP module, inspired by [53]. Mathematically, the first layer of the modified MLP module is formulated as follows: + +$$ +\operatorname {M L P} (x) = \operatorname {I F} (\operatorname {L i n e a r} (\operatorname {B N} (x))) \tag {9} +$$ + +where $x$ represents the input tensor, Linear denotes the linear layer, BN represents the batch normalization layer. Notably, the MLP module consists of two linear layers, each followed by a BN layer and an IF neuron function. + +# 3.4. Random Spike Masking Method + +Implementing the Transformer in SNNs using the ANN-to-SNN conversion method presents a challenge due to the high power consumption demand. To address this issue, we propose the Random Spike Masking (RSM) method for reducing redundant spikes during inference. + +Traditional ANN pruning methods remove weights with low magnitudes, which are believed to have little impact on the final output of the model [58]. In contrast, our RSM method prunes input spikes randomly according to the masking ratio, where each spike $(s = 1)$ has the probability of turning into a failure state $(s = 0)$ that can be implemented using binary mask matrices. + +It is important to note that our proposed RSM method for spike pruning in SNNs differs from Dropout [44] used in ANNs. Dropout is a regularization technique that randomly masks some neurons during training, but all neurons are used for inference, and the output needs to be scaled by the retained probability used during training. This means that Dropout cannot directly reduce the number of spikes in the network. Unlike Dropout, the RSM method reduces the computational cost of SNNs by randomly pruning input spikes in both training and inference, explicitly removing redundancy in input spikes while obtaining excellent performance. + +The RSM method, illustrated in Fig. 2(c-e), randomly generates a binary mask with the same shape as the input spike matrix based on the masking ratio. This determines + +
DatasetModelMethodArchitecture#Param(M)Time StepsAccuracy(%)
CIFAR-10ANN [29]Direct TrainingSwin-T(BN)27.6/98.14
Diet-SNN [39]Direct TrainingVGG-1639.91093.44
tdBN [56]Direct TrainingResNet-1912.6492.92
TET [6]Direct TrainingResNet-1912.6694.50
DSR [32]Direct TrainingPreActResNet-1811.22095.40
Spikformer [57]Direct TrainingSpikformer-4-3849.3495.51
RMP [13]ANN-to-SNNVGG-1639.9204893.63
RNL [7]ANN-to-SNNPreActResNet-1811.225693.45
QCFS [2]ANN-to-SNNRestNet-1811.751296.06
MST (ours)ANN-to-SNNSwin-T(BN)27.66496.32
12897.06
25697.27
CIFAR-100ANN [29]Direct TrainingSwin-T(BN)27.6/88.72
Diet-SNN [39]Direct TrainingVGG-1639.9569.67
tdBN [56]Direct TrainingResNet-1912.6470.86
TET [6]Direct TrainingResNet-1912.6674.72
DSR [32]Direct TrainingPreActResNet-1811.22078.50
SpikformerDirect TrainingSpikformer-4-3849.3478.21
RMP [13]ANN-to-SNNVGG-1639.9204870.93
RNL [7]ANN-to-SNNPreActResNet-1811.225675.10
QCFS [2]ANN-to-SNNRestNet-1811.751279.61
MST (ours)ANN-to-SNNSwin-T(BN)27.66485.40
12886.73
25686.91
ImageNetANN [29]Direct TrainingSwin-T(BN)28.5/80.51
Diet-SNN [39]Direct TrainingVGG-1639.9569.00
tdBN [56]Direct TrainingSEW-ResNet-3421.8467.04
TET [6]Direct TrainingSEW-ResNet-3421.8468.00
DSR [32]Direct TrainingPreActResNet-1811.25067.74
Spikformer [57]Direct TrainingSpikformer-8-76866.3474.81
RMP [13]ANN-to-SNNVGG-1639.9204873.09
QCFS [2]ANN-to-SNNRestNet-1811.7102474.32
MST (ours)ANN-to-SNNSwin-T(BN)28.512877.88
25678.37
51278.51
+ +Table 1. Performance comparison between the proposed model and the SOTA models on different static datasets, where Swin-T (BN) refers to the self-implemented ANN baseline replacing LN with BN [29]. + +which spikes are transmitted for calculation in subsequent neurons, enabling high matrix sparsity. With a masking ratio of $50\%$ , for example, each spike has a $50\%$ chance of being masked, reducing the number of spikes and power consumption. Hence, combining both the SNN-based self-attention mechanism with the RSM approach promises a balance between performance and energy efficiency. + +# 4. Experiments + +We conduct extensive experiments on both static datasets including CIFAR-10 [22], CIFAR-100 [21], and ImageNet datasets [5], and neuromorphic datasets including + +CIFAR10-DVS [24], N-Caltech101 [37], N-Cars [43], ActionRecognition [33], and ASL-DVS [1] datasets, to validate the effectiveness of the MST model. In addition, we evaluate the effect of the RSM approach on accuracy and energy efficiency using the SpikingJelly framework [9]. More details of the training can be found in the supplementary. + +# 4.1. Performance on Static Datasets + +Tab. 1 presents a comprehensive comparison of the MST model with the current SOTA SNN models on the CIFAR-10/100 and ImageNet datasets. The results show that the + +![](images/b248ac5f83f67e1ee1b66ea3bbda47e970d97ba5aa8f1d281ea3df34d55f2ba3.jpg) +Figure 4. Model Architecture for Neuromorphic Datasets. + +proposed MST model outperforms all other models in terms of top-1 accuracy on all three datasets. + +Direct training models, such as Diet-SNN [39], tdBN [56], TET [6], and DSR [32], require lower time steps, but their top-1 accuracy is relatively low, compared to that of the MST model, in which tdBN [56] is $10\%$ less accurate on the CIFAR-100 and ImageNet datasets. + +Conversely, models employing the ANN-to-SNN conversion method typically necessitate a greater number of time steps to reach optimal performance, including RMP [13], RNL [7], and QCFS [2]. The MST model also employs this method but requires only 64 time steps to achieve superior performance, which is far fewer than RMP [13]. This suggests that the MST model can achieve the highest accuracy in a reasonable number of time steps. + +Compared to transformer-based SNN models such as Spikformer [57], the MST model achieves higher top-1 accuracy on all three datasets. Specifically, the top-1 accuracy of the MST model is $1.8\%$ , $8.7\%$ , and $3.7\%$ higher than Spikformer on the CIFAR-10, CIFAR-100, and ImageNet datasets, respectively. Moreover, the MST model has significantly fewer parameters compared to the 8-layer Spikformer [57] model. + +# 4.2. Performance on Neuromorphic Datasets + +We showcase the suitability of the MST model for processing event-based data by evaluating its performance on neuromorphic datasets. Fig. 4 shows the framework for the MST model to process the neuromorphic datasets. We utilize a frame-based representation for preprocessing, where the event streams are transformed into a sequence of high-rate frames. Each event in the stream consists of four dimensions, including two spatial coordinates (x, y), timestamp, and polarity. The frames are integrated into an input tensor of size $(\mathrm{n}\times \mathrm{C},\mathrm{H},\mathrm{W})$ ,where n is the number of frames, C is the number of original channels (which equals two, representing polarity), and H and W represent the height and width of the input, respectively. To align the input dimension with the model, an additional reduction layer is added to the first layer of the entire model, which reduces the channel dimension to 3. This enables us + +
DatasetModelTime StepsAccuracy (%)
CIFAR10-DVSSwin-T (BN)/88.98
TA-SNN [52]1072.00
PLIF [11]2074.80
Dspkie [26]1075.40
DSR [32]1077.30
TET [6]1083.17
NDA [27]1081.70
Spikformer [57]1080.90
12886.60
MST (ours)25687.20
51288.12
N-CALTECH101Swin-T (BN)/92.00
SALT [19]2055.00
NDA [27]1083.70
6484.71
MST (ours)12889.42
25691.38
N-CARSSwin-T (BN)/97.14
CarSNN [48]1086.00
NDA [27]1091.90
3294.67
MST (ours)6496.58
12897.28
Action RecognitionSwin-T (BN)/90.14
STCA [12]1071.20
Mb-SNN [28]1078.10
6484.76
MST (ours)12886.92
25688.21
ASL-DVSSwin-T (BN)/99.90
Meta-SNN [45]10096.04
6498.04
MST (ours)12898.51
25699.10
+ +Table 2. Performance comparison between the proposed model and the SOTA models on different neuromorphic datasets. + +to leverage pre-training weights from the ImageNet dataset, accelerating the training convergence. Data augmentation for SNNs [27] is also applied to improve the accuracy. The ensuing experimental results demonstrate that the proposed fine-tuning approach for ANN-to-SNN conversion achieves remarkably high accuracy. + +The experimental results presented in Tab. 2 demonstrate the effectiveness of the proposed MST model in processing neuromorphic datasets. We compare the MST model with several SOTA SNN models on five popular neuromorphic datasets, including CIFAR10-DVS, N-Caltech101, NCars, Action Recognition, and ASL-DVS dataset. The experimental results show that the MST model achieves the highest top-1 accuracy on all datasets. + +CIFAR10-DVS, N-Caltech101, and N-Cars datasets are + +constructed by converting the static datasets into event data by using event-based cameras. Tab. 2 shows that the MST model outperforms other SOTA SNN models significantly, achieving improvements of $4.95\%$ , $7.68\%$ , and $5.38\%$ on CIFAR10-DVS, N-Caltech101, and N-Cars, respectively. The Action Recognition dataset consists of a series of human actions captured by event-based cameras. By adopting the data preprocessing method of [20], our MST model achieves a top-1 accuracy of $88.21\%$ , which is far higher than other models. Additionally, the ASL-DVS dataset is a large 24-class dataset of gestures and the experimental results demonstrate that our MST model outperforms other SOTA models by $3.06\%$ . + +These results highlight the effectiveness of our proposed MST model in processing various types of neuromorphic datasets. + +# 4.3. Effectiveness of the Random Spike Masking Method + +The ANN-to-SNN conversion method typically involves a large number of time steps, leading to high power consumption. To address this issue, we propose the RSM method for spike pruning, and we demonstrate its effectiveness in the following section. + +Drawing inspiration from knowledge distillation [16], we use the model without masked as a teacher model, and the model after masked as a student model. By fine-tuning the student model, the masked model achieves high performance comparable to the original model without masking in terms of accuracy. This finding highlights the efficacy of the knowledge distillation technique in training masked models without compromising their performance. Consequently, we employ the fine-tuning approach as the training method for our subsequent comparative analysis. + +We evaluate the RSM method in two critical modules in the Transformer: the self-attention (SA) module and the Multi-layer Perceptron (MLP) module. As shown in Fig. 2(d-e), we apply the RSM method to the Query, Key, and Attention matrices in the SA module, as well as the output spike matrix of the first fully connected layer within each block of the MLP module. + +Fig. 5(a) and (b) depict the variation in accuracy for different masking ratios on the CIFAR-10 and CIFAR-100 datasets, respectively. The experimental results demonstrate that the accuracy decreases with the increasing masking ratio for both the SA and MLP modules, but their sensitivity to masking ratio changes differs. Specifically, the accuracy of the SA module remains stable over a certain range of masking ratios. In contrast, the accuracy of the MLP module declines more sharply and is more sensitive to masking ratio changes. Consistent with prior research [34, 49], the redundancy in the SA module enables the MST to withstand the losses caused by missing input spikes with + +![](images/6faf2ceee2114643d5131e26d5123b257fa82443ebfe7cc4e72df0ed9dc2610b.jpg) + +![](images/33a1b502007c475da3927f56b6ae28b7631c937ae34c98efc8d03ceb58f21856.jpg) + +![](images/ba202c8b34f3612eaad0b9798d9017e973b81cd93626f5adc0bc5c8fa0356297.jpg) + +![](images/12937ad9b9a231509fed4aa82780f80d28c533b529eb6c6516ed611f8811ca20.jpg) + +![](images/23340100e6adda5fbff85a8e0a895c1b4f79f391baadfe93e070b1d9cd97309e.jpg) +Figure 5. The effectiveness of the RSM method in (a) SA and (b) MLP modules of the MST model, as well as in Spiking (c) ResNet-18 and (d) VGG-16 models, with varying masking ratios. The inset photographs show the standard deviation of accuracy in 10 runs. +Figure 6. Comparison of the accuracy of masking different numbers of blocks on the CIFAR-100 dataset. + +out significantly affecting the overall performance of the SNN. + +In addition to the variation in sensitivity to changes in the masking ratio between different modules, our experiments also demonstrate that the sensitivity can vary depending on the dataset used. The CIFAR-10 dataset is relatively less sensitive to changes in the masking ratio, with only a $0.1\%$ decrease in accuracy when the masking ratio reaches $80\%$ . In contrast, the CIFAR-100 dataset is more sensitive to changes in the masking ratio, experiencing a more substantial accuracy decline as the masking ratio increases. + +We also investigate the potential of the RSM method as a general approach for reducing power consumption in the context of ANN-to-SNN conversion. By applying the RSM + +
ModelRandom RatioP (α Watts)Accuracy (%)
MST0%3.9G (×1)97.27 (+0)
50%3.2G (×0.82)97.25 (-0.02)
75%2.9G (×0.74)97.29 (+0.02)
ResNet-180%58.2M (×1)96.48 (+0)
50%40.7M (×0.70)92.88 (-3.60)
75%34.1M (×0.58)82.68 (-13.80)
VGG-160%24.4M (×1)95.46 (+0)
50%18.9M (×0.77)89.56 (-5.90)
75%16.7M (×0.68)79.09 (-16.37)
+ +Table 3. Comparison of power consumption and accuracy between models with a Masking ratio of $0\%$ , $50\%$ , and $75\%$ on the CIFAR-10 dataset, respectively. $(\dots)$ in the table denotes the power consumption/accuracy compared to the unmasked model (with $0\%$ random ratio). + +method to other SNN models like Spiking ResNet-18 and VGG-16 and introducing a masking ratio to each convolution layer, we aim to decrease the transmitted spikes. Our results, presented in Fig. 5, demonstrate that the redundancy of these models can also be leveraged to maintain performance while reducing power consumption within a specific range. This indicates the potential of the RSM method for widespread applications in various SNN models for improving energy efficiency. + +Fig. 6 illustrates the impact of masking different numbers of blocks on the accuracy of the MST model. Our results indicate a non-linear, positive relationship between the number of masked blocks and performance loss. Notably, masking the first 2-5 blocks causes a slight performance loss, and the loss increases with more masked blocks until saturation at around 9-10 blocks. These observations provide valuable insights for designing partially masked blocks. + +To better evaluate the effects of the RSM method on energy consumption reduction, we utilize theoretical estimates of energy consumption on neuromorphic chips based on previous studies [4, 7]. Assuming that a spike activity consumes $\alpha$ Joules and 1 time step takes $1\mathrm{ms}$ . Then the power model is defined as: + +$$ +P = \frac {\text {t o t a l s p i k e s}}{1 \times 1 0 ^ {- 3}} \times \alpha (\text {W a t t s}) \tag {10} +$$ + +Tab. 3 presents the power consumption and accuracy of the MST, ResNet-18, and VGG-16 at $0\%$ , $50\%$ , and $75\%$ masking ratios on the CIFAR-10 dataset. The RSM method is applied to the SA module in the MST and each block in ResNet-18 and VGG-16. The results demonstrate that the RSM method has a direct effect on the number of spikes transmitted, which in turn reduces power consumption. In specific, applying the RSM method to the MST + +![](images/d1263df0a69bbd320b189d3a5abc5227b2d808365ee9953a28f2c382fe0f240f.jpg) +Figure 7. Comparison of attention maps between the MST model with $0\%$ , $50\%$ , and $75\%$ masking ratio (from top to bottom) with 5 different time steps. + +model can reduce power consumption by $26.8\%$ without any loss in performance when the masking ratio reaches $75\%$ . This finding suggests that there exist substantial redundant spikes in the SA module that can be pruned for better energy efficiency. As for ResNet-18 and VGG-16, the RSM method also yields significant power reduction. For instance, ResNet-18 can reduce power consumption by $30.1\%$ with a moderate accuracy loss of $3.6\%$ . However, excessive masking leads to a significant drop in accuracy. + +In summary, our results demonstrate that the proposed RSM method is effective when applied to the SA module in the Transformer, as well as other SNN models. By eliminating redundant spikes, the RSM method reduces power consumption while preserving performance, making it a promising approach for energy-efficient ANN-to-SNN conversion. + +To visualize the impact of different masking ratios on attention maps, we compared the models with $0\%$ , $50\%$ , and $75\%$ masking ratios using the Spike Activation Maps (SAM) method. The results, shown in Fig. 7, demonstrate that the models with different masking ratios concentrate on similar areas of the object at the same time step, with the red parts outlining the object. Comparison with the ANN model using the ScoreCAM method [50] reveals that both models focus on similar key information. These results suggest that the proposed RSM method preserves the regions of interest within the model, contributing to accuracy preservation. + +# 5. Discussion + +In this paper, we proposed the Masked Spiking Transformer (MST) with the Random Spike Masking (RSM) method. By pruning input spikes, the proposed RSM method effectively reduces power consumption while maintaining the performance of the model within a certain range. + +Though our experiments highlight the superiority of the MST model over state-of-the-art SNN models, our model still has limitations that need addressing. A key constraint is the relatively long time steps needed by the ANN-to-SNN + +conversion method, limiting the suitability of the proposed model for real-time applications with strict timing demands. + +Furthermore, even though the RSM method reduces the number of spikes and energy consumption, the experiment in this article merely investigates its applicability of ANN-to-SNN conversion, thus exhibiting relatively high energy consumption compared to direct-trained SNN models, which take fewer time steps. Consequently, future research could apply the RSM method to direct training methods to optimize energy consumption further and make SNNs more practical for real-world applications. Additionally, adopting different masking ratios across layers may achieve a better balance between performance and energy efficiency. + +# 6. Conclusion + +In this work, we propose a Masked Spiking Transformer (MST) framework that combines the energy efficiency of SNNs with the high-performance self-attention mechanism of Transformers using the ANN-to-SNN method. Additionally, we introduce a Random Spike Masking (RSM) method to prune input spikes, thus reducing power consumption. The experimental results demonstrate that the MST model outperforms current SOTA SNN models on both static and neuromorphic datasets. Furthermore, the proposed RSM method shows significant power reduction while maintaining performance in different modules of the Transformer and other SNN models. Our work opens up new possibilities for developing high-performance SNN models, paving the way for future research in this area. + +# 7. Acknowledgement + +This work is supported by the Guangzhou-HKUST(GZ) Joint Funding Program (Grant No. 2023A03J0682), HK RGC (Grant Nos. 27206321, 17205922, 17212923), NSFC (Grant No. 62122004), National Key R&D Program of China (Grant No. SQ2022YFB3600159). This research is also partially supported by ACCESS - AI Chip Center for Emerging Smart Systems, sponsored by Innovation and Technology Fund (ITF), Hong Kong SAR. + +# References + +[1] Yin Bi, Aaron Chadha, Alhabib Abbas, Eirina Bourtsovatze, and Yiannis Andreopoulos. Graph-based object classification for neuromorphic vision sensing. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 491-501, 2019. +[2] Tong Bu, Wei Fang, Jianhao Ding, PengLin Dai, Zhaofei Yu, and Tiejun Huang. Optimal ANN-SNN Conversion for High-accuracy and Ultra-low-latency Spiking Neural Networks. In International Conference on Learning Representations, 2021. + +[3] Yongqiang Cao, Yang Chen, and Deepak Khosla. Spiking deep convolutional neural networks for energy-efficient object recognition. International Journal of Computer Vision, 113(1):54-66, 2015. +[4] Yongqiang Cao, Yang Chen, and Deepak Khosla. Spiking deep convolutional neural networks for energy-efficient object recognition. International Journal of Computer Vision, 113:54-66, 2015. +[5] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In 2009 IEEE Conference on Computer Vision and Pattern Recognition, pages 248–255. IEEE, 2009. +[6] Shikuang Deng, Yuhang Li, Shanghai Zhang, and Shi Gu. Temporal Efficient Training of Spiking Neural Network via Gradient Re-weighting. arXiv preprint arXiv:2202.11946, 2022. +[7] Jianhao Ding, Zhaofei Yu, Yonghong Tian, and Tiejun Huang. Optimal ann-snn conversion for fast and accurate inference in deep spiking neural networks. arXiv preprint arXiv:2105.11654, 2021. +[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, and Sylvain Gelly. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020. +[9] Wei Fang, Yanqi Chen, Jianhao Ding, Ding Chen, Zhaofei Yu, Huihui Zhou, Timothée Masquelier, Yonghong Tian, and other contributors. Spikingjelly. https://github.com/fangwei123456/spikingjelly, 2020. Accessed: 2023-02-21. +[10] Wei Fang, Zhaofei Yu, Yanqi Chen, Tiejun Huang, Timothee Masquelier, and Yonghong Tian. Deep residual learning in spiking neural networks. Advances in Neural Information Processing Systems, 34:21056-21069, 2021. +[11] Wei Fang, Zhaofei Yu, Yanqi Chen, Timothée Masquelier, Tiejun Huang, and Yonghong Tian. Incorporating learnable membrane time constant to enhance learning of spiking neural networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2661-2671, 2021. +[12] Pengjie Gu, Rong Xiao, Gang Pan, and Huajin Tang. STCA: Spatio-Temporal Credit Assignment with Delayed Feedback in Deep Spiking Neural Networks. In Proceedings of the Twenty-Eighth International Joint Conference on Artificial Intelligence, pages 1366-1372, Macao, China, Aug. 2019. International Joint Conferences on Artificial Intelligence Organization. +[13] Bing Han, Gopalakrishnan Srinivasan, and Kaushik Roy. Rmp-snn: Residual membrane potential neuron for enabling deeper high-accuracy and low-latency spiking neural network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13558–13567, 2020. +[14] Ali Hassani, Steven Walton, Nikhil Shah, Abulikemu Abuduweili, Jiachen Li, and Humphrey Shi. Escaping the big data paradigm with compact transformers. arXiv preprint arXiv:2104.05704, 2021. + +[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016. +[16] Geoffrey Hinton, Oriol Vinyals, and Jeff Dean. Distilling the Knowledge in a Neural Network, Mar. 2015. +[17] Eugene M. Izhikevich. Simple model of spiking neurons. IEEE Transactions on neural networks, 14(6):1569-1572, 2003. +[18] Youngeun Kim and Priyadarshini Panda. Optimizing deeper spiking neural networks for dynamic vision sensing. Neural Networks, 144:686-698, 2021. +[19] Youngeun Kim and Priyadarshini Panda. Optimizing deeper spiking neural networks for dynamic vision sensing. Neural Networks, 144:686-698, 2021. +[20] Karthik Sivarama Krishnan and Koushik Sivarama Krishnan. Benchmarking Conventional Vision Models on Neuromorphic Fall Detection and Action Recognition Dataset. In 2022 IEEE 12th Annual Computing and Communication Workshop and Conference (CCWC), pages 0518-0523. IEEE, 2022. +[21] Alex Krizhevsky and Geoffrey Hinton. Learning multiple layers of features from tiny images. 2009. +[22] Y. Lecun, L. Bottou, Y. Bengio, and P. Haffner. Gradient-based learning applied to document recognition. Proceedings of the IEEE, 86(11):2278-2324, Nov. 1998. +[23] William B. Levy and Robert A. Baxter. Energy-Efficient Neuronal Computation via Quantal Synaptic Failures. Journal of Neuroscience, 22(11):4746-4755, June 2002. +[24] Hongmin Li, Hanchao Liu, Xiangyang Ji, Guoqi Li, and Luping Shi. CIFAR10-DVS: An Event-Stream Dataset for Object Classification. Frontiers in Neuroscience, 11, 2017. +[25] Yuhang Li, Shikuang Deng, Xin Dong, Ruihao Gong, and Shi Gu. A free lunch from ANN: Towards efficient, accurate spiking neural networks calibration. In International Conference on Machine Learning, pages 6316-6325. PMLR, 2021. +[26] Yuhang Li, Yufei Guo, Shanghang Zhang, Shikuang Deng, Yongqing Hai, and Shi Gu. Differentiable spike: Rethinking gradient-descent for training spiking neural networks. Advances in Neural Information Processing Systems, 34:23426-23439, 2021. +[27] Yuhang Li, Youngeun Kim, Hyoungseob Park, Tamar Geller, and Priyadarshini Panda. Neuromorphic Data Augmentation for Training Spiking Neural Networks. arXiv preprint arXiv:2203.06145, 2022. +[28] Qianhui Liu, Dong Xing, Huajin Tang, De Ma, and Gang Pan. Event-based Action Recognition Using Motion Information and Spiking Neural Networks. In Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence, pages 1743-1749, Montreal, Canada, Aug. 2021. International Joint Conferences on Artificial Intelligence Organization. +[29] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10012-10022, 2021. + +[30] Wolfgang Maass. Networks of spiking neurons: The third generation of neural network models. Neural networks, 10(9):1659-1671, 1997. +[31] Warren S. McCulloch and Walter Pitts. A logical calculus of the ideas immanent in nervous activity. The bulletin of mathematical biophysics, 5(4):115-133, 1943. +[32] Qingyan Meng, Mingqing Xiao, Shen Yan, Yisen Wang, Zhouchen Lin, and Zhi-Quan Luo. Training High-Performance Low-Latency Spiking Neural Networks by Differentiation on Spike Representation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12444–12453, 2022. +[33] Shu Miao, Guang Chen, Xiangyu Ning, Yang Zi, Kejia Ren, Zhenshan Bing, and Alois Knoll. Neuromorphic vision datasets for pedestrian detection, action recognition, and fall detection. Frontiers in neurorobotics, 13:38, 2019. +[34] Paul Michel, Omer Levy, and Graham Neubig. Are sixteen heads really better than one? Advances in neural information processing systems, 32, 2019. +[35] Etienne Mueller, Viktor Studenyak, Daniel Auge, and Alois Knoll. Spiking Transformer Networks: A Rate Coded Approach for Processing Sequential Data. In 2021 7th International Conference on Systems and Informatics (ICSAI), pages 1-5, Nov. 2021. +[36] Emre O. Neftci, Hesham Mostafa, and Friedemann Zenke. Surrogate Gradient Learning in Spiking Neural Networks: Bringing the Power of Gradient-Based Optimization to Spiking Neural Networks. IEEE Signal Processing Magazine, 36(6):51-63, Nov. 2019. +[37] Garrick Orchard, Ajinkya Jayawant, Gregory K. Cohen, and Nitish Thakor. Converting Static Image Datasets to Spiking Neuromorphic Datasets Using Saccades. Frontiers in Neuroscience, 9, 2015. +[38] Wachirawit Ponghiran and Kaushik Roy. Spiking neural networks with improved inherent recurrence dynamics for sequential learning. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 8001-8008, 2022. +[39] Nitin Rathi and Kaushik Roy. DIET-SNN: Direct Input Encoding With Leakage and Threshold Optimization in Deep Spiking Neural Networks, Dec. 2020. +[40] Nitin Rathi, Gopalakrishnan Srinivasan, Priyadarshini Panda, and Kaushik Roy. Enabling deep spiking neural networks with hybrid conversion and spike timing dependent backpropagation. arXiv preprint arXiv:2005.01807, 2020. +[41] Bodo Rueckauer, Iulia-Alexandra Lungu, Yuhuang Hu, Michael Pfeiffer, and Shih-Chii Liu. Conversion of continuous-valued deep networks to efficient event-driven networks for image classification. Frontiers in neuroscience, 11:682, 2017. +[42] Karen Simonyan and Andrew Zisserman. Very Deep Convolutional Networks for Large-Scale Image Recognition, Apr. 2015. +[43] Amos Sironi, Manuele Brambilla, Nicolas Bourdis, Xavier Lagorce, and Ryad Benosman. HATS: Histograms of Averaged Time Surfaces for Robust Event-Based Object Classification. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1731-1740, 2018. + +[44] Nitish Srivastava, Geoffrey Hinton, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. Dropout: A simple way to prevent neural networks from overfitting. The journal of machine learning research, 15(1):1929-1958, 2014. +[45] Kenneth M. Stewart and Emre O. Neftci. Meta-learning spiking neural networks with surrogate gradient descent. Neuro-morphic Computing and Engineering, 2(4):044002, 2022. +[46] Christoph Stöckl and Wolfgang Maass. Optimized spiking neurons can classify images with high accuracy through temporal coding with two spikes. Nature Machine Intelligence, 3(3):230-238, 2021. +[47] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, $\backslash$ Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. +[48] Alberto Viale, Alberto Marchisio, Maurizio Martina, Guido Masera, and Muhammad Shafique. Carsnn: An efficient spiking neural network for event-based autonomous cars on the loihi neuromorphic research processor. In 2021 International Joint Conference on Neural Networks (IJCNN), pages 1-10. IEEE, 2021. +[49] Elena Voita, David Talbot, Fedor Moiseev, Rico Sennrich, and Ivan Titov. Analyzing multi-head self-attention: Specialized heads do the heavy lifting, the rest can be pruned. arXiv preprint arXiv:1905.09418, 2019. +[50] Haofan Wang, Zifan Wang, Mengnan Du, Fan Yang, Zijian Zhang, Sirui Ding, Piotr Mardziel, and Xia Hu. Score-CAM: Score-Weighted Visual Explanations for Convolutional Neural Networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops, pages 24–25, 2020. +[51] Zheyu Yang, Yujie Wu, Guanrui Wang, Yukuan Yang, Guoqi Li, Lei Deng, Jun Zhu, and Luping Shi. DashNet: A hybrid artificial and spiking neural network for high-speed object tracking. arXiv preprint arXiv:1909.12942, 2019. +[52] Man Yao, Huanhuan Gao, Guangshe Zhao, Dingheng Wang, Yihan Lin, Zhaoxu Yang, and Guoqi Li. Temporal-wise attention spiking neural networks for event streams classification. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10221-10230, 2021. +[53] Zhuliang Yao, Yue Cao, Yutong Lin, Ze Liu, Zheng Zhang, and Han Hu. Leveraging batch normalization for vision transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 413-422, 2021. +[54] Jiqing Zhang, Bo Dong, Haiwei Zhang, Jianchuan Ding, Felix Heide, Baocai Yin, and Xin Yang. Spiking Transformers for Event-Based Single Object Tracking. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8801-8810, 2022. +[55] Jiyuan Zhang, Lulu Tang, Zhaofei Yu, Jiwen Lu, and Tiejun Huang. Spike Transformer: Monocular Depth Estimation for Spiking Camera. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part VII, pages 34-52. Springer, 2022. +[56] Hanle Zheng, Yujie Wu, Lei Deng, Yifan Hu, and Guoqi Li. Going deeper with directly-trained larger spiking neural networks. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 11062-11070, 2021. + +[57] Zhaokun Zhou, Yuesheng Zhu, Chao He, Yaowei Wang, Shuicheng Yan, Yonghong Tian, and Li Yuan. Spikformer: When Spiking Neural Network Meets Transformer. arXiv preprint arXiv:2209.15425, 2022. +[58] Michael Zhu and Suyog Gupta. To prune, or not to prune: Exploring the efficacy of pruning for model compression, Nov. 2017. \ No newline at end of file diff --git a/2023/Masked Spiking Transformer/images.zip b/2023/Masked Spiking Transformer/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..6156f39490abbac619fb8d13845305664c9917af --- /dev/null +++ b/2023/Masked Spiking Transformer/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:44ef405d4b163853bc0d1b695afd27c9985e3e599dd9cc8dbcea90ef1b735655 +size 601379 diff --git a/2023/Masked Spiking Transformer/layout.json b/2023/Masked Spiking Transformer/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..143c97810efc883bbfa9c96820bb57c9259bf647 --- /dev/null +++ b/2023/Masked Spiking Transformer/layout.json @@ -0,0 +1,9105 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 205, + 103, + 389, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 205, + 103, + 389, + 121 + ], + "spans": [ + { + "bbox": [ + 205, + 103, + 389, + 121 + ], + "type": "text", + "content": "Masked Spiking Transformer" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "spans": [ + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "text", + "content": "Ziqing Wang" + }, + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "inline_equation", + "content": "^{1,2*}" + }, + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "text", + "content": " Yuetong Fang" + }, + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "text", + "content": " Jiahang Cao" + }, + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "text", + "content": " Qiang Zhang" + }, + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "text", + "content": " Zhongrui Wang" + }, + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "inline_equation", + "content": "^{3,4\\dagger}" + }, + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "text", + "content": " Renjing Xu" + }, + { + "bbox": [ + 53, + 141, + 539, + 159 + ], + "type": "inline_equation", + "content": "^{1\\dagger}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 107, + 171, + 485, + 184 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 107, + 171, + 485, + 184 + ], + "spans": [ + { + "bbox": [ + 107, + 171, + 485, + 184 + ], + "type": "text", + "content": "1The Hong Kong University of Science and Technology (Guangzhou) 2North Carolina State University" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 133, + 185, + 460, + 198 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 133, + 185, + 460, + 198 + ], + "spans": [ + { + "bbox": [ + 133, + 185, + 460, + 198 + ], + "type": "text", + "content": "3The University of Hong Kong 4ACCESS - AI Chip Center for Emerging Smart Systems" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 100, + 215, + 492, + 227 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 100, + 215, + 492, + 227 + ], + "spans": [ + { + "bbox": [ + 100, + 215, + 492, + 227 + ], + "type": "text", + "content": "zwang247@ncsu.edu, {yfang870, jcao248, qzhang749}@connect.hkust-gz.edu.cn" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 203, + 230, + 391, + 240 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 203, + 230, + 391, + 240 + ], + "spans": [ + { + "bbox": [ + 203, + 230, + 391, + 240 + ], + "type": "text", + "content": "zrwang@eee.hku.hk, renjingxu@ust.hk" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 143, + 269, + 192, + 281 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 269, + 192, + 281 + ], + "spans": [ + { + "bbox": [ + 143, + 269, + 192, + 281 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 294, + 290, + 558 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 294, + 290, + 558 + ], + "spans": [ + { + "bbox": [ + 47, + 294, + 290, + 558 + ], + "type": "text", + "content": "The combination of Spiking Neural Networks (SNNs) and Transformers has attracted significant attention due to their potential for high energy efficiency and high-performance nature. However, existing works on this topic typically rely on direct training, which can lead to suboptimal performance. To address this issue, we propose to leverage the benefits of the ANN-to-SNN conversion method to combine SNNs and Transformers, resulting in significantly improved performance over existing state-of-the-art SNN models. Furthermore, inspired by the quantal synaptic failures observed in the nervous system, which reduce the number of spikes transmitted across synapses, we introduce a novel Masked Spiking Transformer (MST) framework. This incorporates a Random Spike Masking (RSM) method to prune redundant spikes and reduce energy consumption without sacrificing performance. Our experimental results demonstrate that the proposed MST model achieves a significant reduction of " + }, + { + "bbox": [ + 47, + 294, + 290, + 558 + ], + "type": "inline_equation", + "content": "26.8\\%" + }, + { + "bbox": [ + 47, + 294, + 290, + 558 + ], + "type": "text", + "content": " in power consumption when the masking ratio is " + }, + { + "bbox": [ + 47, + 294, + 290, + 558 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 47, + 294, + 290, + 558 + ], + "type": "text", + "content": " while maintaining the same level of performance as the unmasked model. The code is available at: https://github.com/bic-L/Masked-Spiking-Transformer." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 581, + 128, + 594 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 581, + 128, + 594 + ], + "spans": [ + { + "bbox": [ + 47, + 581, + 128, + 594 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 601, + 287, + 685 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 601, + 287, + 685 + ], + "spans": [ + { + "bbox": [ + 46, + 601, + 287, + 685 + ], + "type": "text", + "content": "Spiking neural networks (SNNs), considered as the next generation neural networks [30], are brain-inspired neural networks based on the dynamic characteristics of biological neurons [31, 17]. SNNs have attracted significant attention due to their unique properties in handling sparse data, which can yield great energy efficiency benefits on neuromorphic hardware. Due to their specialties, they have been widely" + } + ] + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 305, + 281, + 425, + 441 + ], + "blocks": [ + { + "bbox": [ + 305, + 281, + 425, + 441 + ], + "lines": [ + { + "bbox": [ + 305, + 281, + 425, + 441 + ], + "spans": [ + { + "bbox": [ + 305, + 281, + 425, + 441 + ], + "type": "image", + "image_path": "f1c7ed3952b75e5d050a894adccea07a6265f2ddd01dcdb238d5d7ee6dcaa56e.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 456, + 547, + 534 + ], + "lines": [ + { + "bbox": [ + 304, + 456, + 547, + 534 + ], + "spans": [ + { + "bbox": [ + 304, + 456, + 547, + 534 + ], + "type": "text", + "content": "Figure 1. Performance of MST and other SOTA SNN models regarding top-1 accuracy and time steps. The markers, represented by circles and star shapes, denote the direct training (DT) and the ANN-to-SNN (A2S) conversion method, respectively, where the marker size corresponds to the model size. Results show that the proposed MST model achieves higher accuracy than the other SNN models." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 428, + 281, + 549, + 442 + ], + "blocks": [ + { + "bbox": [ + 428, + 281, + 549, + 442 + ], + "lines": [ + { + "bbox": [ + 428, + 281, + 549, + 442 + ], + "spans": [ + { + "bbox": [ + 428, + 281, + 549, + 442 + ], + "type": "image", + "image_path": "df80e8530cbd60dd165de468d9a4cd683e6048d0e4ca1ca9b356d83b5b4d7d05.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 555, + 545, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 555, + 545, + 616 + ], + "spans": [ + { + "bbox": [ + 304, + 555, + 545, + 616 + ], + "type": "text", + "content": "utilized in various fields, such as classification [32, 18], object detection [3] and tracking [51], etc. Nevertheless, SNNs currently can hardly realize a comparable performance to that of artificial neural networks (ANNs), especially for complex tasks such as ImageNet [40]." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 617, + 546, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 546, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 546, + 715 + ], + "type": "text", + "content": "In order to improve the performance of SNNs, various training methods have been proposed, broadly categorized as the direct training method and the ANN-to-SNN conversion method. Direct training methods leverage a continuous relaxation of the non-smooth spiking mechanism to enable backpropagation with a surrogate gradient function for handling non-differentiability [36], but this can lead to unstable gradient propagation and relatively low accuracy" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 693, + 127, + 703 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 693, + 127, + 703 + ], + "spans": [ + { + "bbox": [ + 58, + 693, + 127, + 703 + ], + "type": "text", + "content": "*Equal contribution." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 59, + 703, + 135, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 703, + 135, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 703, + 135, + 712 + ], + "type": "text", + "content": "† Corresponding author" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "1761" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 203 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 203 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 203 + ], + "type": "text", + "content": "compared to leading ANNs [38]. Alternatively, ANN-to-SNN conversion methods convert pre-trained ANNs into SNNs for better performance while requiring more time steps, with increased power consumption to reduce conversion errors [46, 25, 2, 7]. Our focus is on implementing the ANN-to-SNN conversion method to narrow the performance gap between leading ANNs and SNNs, but the required long time steps pose challenges in reducing energy consumption. Therefore, identifying strategies to decrease power consumption while maintaining excellent performance is crucial." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 204, + 289, + 443 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 204, + 289, + 443 + ], + "spans": [ + { + "bbox": [ + 46, + 204, + 289, + 443 + ], + "type": "text", + "content": "The biological nervous system offers valuable insights for addressing the challenges of implementing high-performance Spiking Transformers using the ANN-to-SNN conversion method. The quantal synaptic failure theory suggests that missing information during neuronal signal transmission may not impact the computational information transmitted to a postsynaptic neuron under certain conditions, but can reduce energy consumption and heat production [23]. Likewise, in the ANN-to-SNN conversion process, missing spikes can possibly be compensated for by leveraging the correlations between signals in the space and time domains during the information propagation over multiple time steps. In addition, neural network models possess lots of redundant connections: prior works reveal that the redundancy in the self-attention module of Transformers can be pruned without significantly impacting performance [34, 49]. Therefore, eliminating redundant information during the transmission of neuronal signals can possibly reduce overall energy consumption in the Spiking Transformer model while preserving high performance." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 443, + 289, + 658 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 443, + 289, + 658 + ], + "spans": [ + { + "bbox": [ + 46, + 443, + 289, + 658 + ], + "type": "text", + "content": "In our work, we propose a Masked Spiking Transformer (MST), which incorporates a Random Spike Masking (RSM) method designed specifically for SNNs. The RSM method randomly selects only a subset of input spikes, significantly reducing the number of spikes involved in the computation process. We evaluate the MST model on both static and neuromorphic datasets, demonstrating its superiority over existing SNN models. Our experiments show that the RSM method can reduce energy consumption on the self-attention module and the MLP module in Transformer, enabling the SNNs to take advantage of energy efficiency and high performance. Furthermore, the proposed RSM method is not limited to Transformer, but can be extended to other backbones such as ResNet and VGG, highlighting its potential as a general technique to improve SNN efficiency. Our results demonstrate the potential of this approach to provide a new direction for developing high-performance and energy-efficient SNN models." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 658, + 288, + 682 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 658, + 288, + 682 + ], + "spans": [ + { + "bbox": [ + 47, + 658, + 288, + 682 + ], + "type": "text", + "content": "The main contributions of this paper can be summarized as follows:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 58, + 689, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 689, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 58, + 689, + 288, + 714 + ], + "type": "text", + "content": "- We propose a Masked Spiking Transformer (MST) using the ANN-to-SNN conversion method. To the best" + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 305, + 71, + 556, + 241 + ], + "blocks": [ + { + "bbox": [ + 305, + 71, + 556, + 241 + ], + "lines": [ + { + "bbox": [ + 305, + 71, + 556, + 241 + ], + "spans": [ + { + "bbox": [ + 305, + 71, + 556, + 241 + ], + "type": "image", + "image_path": "3f36b6897dc51e05c932bfa271512da956a15bc4fd01b24b1f0e6b13e8659968.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 251, + 547, + 327 + ], + "lines": [ + { + "bbox": [ + 304, + 251, + 547, + 327 + ], + "spans": [ + { + "bbox": [ + 304, + 251, + 547, + 327 + ], + "type": "text", + "content": "Figure 2. Overview of our MST. (a) Schematic of the model architecture of the Swin Transformer, which is the backbone of our model. (b) Schematic of the proposed Transformer blocks, where BN layers replace the original LN layers. (c) Conceptual illustration of the RSM method, which involves randomly masking the input spike. (d-e) The RSM method in self-attention and MLP module." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "bbox": [ + 324, + 348, + 545, + 384 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 324, + 348, + 545, + 384 + ], + "spans": [ + { + "bbox": [ + 324, + 348, + 545, + 384 + ], + "type": "text", + "content": "of our knowledge, it is the first exploration of applying the self-attention mechanism fully in SNNs utilizing the ANN-to-SNN conversion method." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 392, + 545, + 586 + ], + "type": "list", + "angle": 0, + "index": 11, + "blocks": [ + { + "bbox": [ + 317, + 392, + 545, + 475 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 392, + 545, + 475 + ], + "spans": [ + { + "bbox": [ + 317, + 392, + 545, + 475 + ], + "type": "text", + "content": "- The MST model is evaluated on both static and neuromorphic datasets, and the results show that it outperforms state-of-the-art (SOTA) SNNs on all datasets. In specific, the top-1 accuracy of the MST model is " + }, + { + "bbox": [ + 317, + 392, + 545, + 475 + ], + "type": "inline_equation", + "content": "1.21\\%" + }, + { + "bbox": [ + 317, + 392, + 545, + 475 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 317, + 392, + 545, + 475 + ], + "type": "inline_equation", + "content": "7.3\\%" + }, + { + "bbox": [ + 317, + 392, + 545, + 475 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 317, + 392, + 545, + 475 + ], + "type": "inline_equation", + "content": "3.7\\%" + }, + { + "bbox": [ + 317, + 392, + 545, + 475 + ], + "type": "text", + "content": " higher than the current SOTA SNN model on the CIFAR-10, CIFAR-100, and ImageNet datasets, respectively." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 317, + 483, + 545, + 532 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 483, + 545, + 532 + ], + "spans": [ + { + "bbox": [ + 317, + 483, + 545, + 532 + ], + "type": "text", + "content": "- We design a Random Spike Masking (RSM) method for SNNs trained with the ANN-to-SNN conversion method to prune the redundant spikes during inference and save energy consumption." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 317, + 539, + 545, + 586 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 539, + 545, + 586 + ], + "spans": [ + { + "bbox": [ + 317, + 539, + 545, + 586 + ], + "type": "text", + "content": "- Extensive experiments show that our proposed RSM is a versatile and general method that can be utilized in other spike-based deep networks, such as ResNet and VGG SNN model variants." + } + ] + } + ], + "index": 10 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 617, + 392, + 631 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 617, + 392, + 631 + ], + "spans": [ + { + "bbox": [ + 306, + 617, + 392, + 631 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 641, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 545, + 715 + ], + "type": "text", + "content": "Spiking Neural Networks SNNs have gained popularity in the field of brain-inspired intelligence due to their compatibility with neuromorphic hardware and biological properties. With the increasing interest in larger-scale and higher-performance SNNs, recent research has focused on developing novel training algorithms and architectures." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1762" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 264 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 264 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 264 + ], + "type": "text", + "content": "Zheng et al. proposed a threshold-dependent batch normalization (tdBN) method based on spatiotemporal backpropagation to train a large-scale SNN model with 50 layers [56]. Besides, Fang et al. proposed the SEW ResNet architecture for residual learning in deep SNNs to overcome the gradient vanishing problem [10]. Later, they introduced a training algorithm that learns the threshold of each spiking neuron to improve the performance of SNNs [11]. However, these methods mainly discuss the SNN models that are dominated by convolutional layers, such as the SNN variants of VGG [42] and ResNet [15]. Despite their improvements, the performance of these methods still struggles to match their ANN counterparts, limiting the application of SNNs. In this context, our proposed work focuses on implementing the self-attention mechanism in SNNs to design a Spiking Transformer that improves the performance of SNNs." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 279, + 289, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 279, + 289, + 460 + ], + "spans": [ + { + "bbox": [ + 46, + 279, + 289, + 460 + ], + "type": "text", + "content": "Transformer Transformer [47] was first introduced in Natural Language Processing (NLP) and quickly gained popularity for its remarkable capabilities in capturing long-range dependencies. Its success in NLP has inspired researchers to explore its potential in computer vision. Vision Transformer (ViT) [8] was the first attempt to apply the Transformer to image classification. ViT has achieved impressive results on various computer vision benchmarks, demonstrating the effectiveness of the self-attention mechanism in image understanding. Following the success of ViT, a series of works [29, 14] proposed improvements to the original ViT architecture. Motivated by the success of Transformers and its variations, this paper proposes a new architecture for SNNs that leverages the capacities of the Transformer and the energy efficiency of SNNs." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 474, + 289, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 474, + 289, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 474, + 289, + 713 + ], + "type": "text", + "content": "Spiking Transformer The combination of the Transformer and SNNs can achieve better performance, which has been discussed in prior studies, including STNet [54] and Spike-T [55]. These models utilized separate branches of SNNs and Transformers for feature extraction, leading to the inability to run independently on neuromorphic hardware and failing to exploit the energy efficiency benefits of SNNs fully. In addition, Mueller et al. [35] proposed a Spiking Transformer using the ANN-to-SNN conversion method, but they did not implement the self-attention module in SNNs. The recently proposed Spikformer [57] directly trained the Transformer in SNNs, but still struggles to achieve comparable performance to leading ANNs. To address these limitations, we apply the self-attention mechanism fully in SNNs by utilizing the ANN-to-SNN conversion method and propose the RSM method to improve both the performance and energy efficiency of the Spiking Transformer. Our model offers a new direction for developing high-performance SNNs using the ANN-to-SNN conversion method." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 306, + 71, + 367, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 71, + 367, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 71, + 367, + 84 + ], + "type": "text", + "content": "3. Methods" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 306, + 93, + 436, + 106 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 93, + 436, + 106 + ], + "spans": [ + { + "bbox": [ + 306, + 93, + 436, + 106 + ], + "type": "text", + "content": "3.1. Spiking Neuron Model" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "spans": [ + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "text", + "content": "For ANNs, the input " + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "inline_equation", + "content": "\\pmb{a}^{l-1}" + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "text", + "content": " to layer " + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "text", + "content": " is mapped to the output " + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "inline_equation", + "content": "\\pmb{a}^l" + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "text", + "content": " by a linear transformation matrix " + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "inline_equation", + "content": "\\pmb{W}^l" + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "text", + "content": " and a nonlinear activation function " + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "inline_equation", + "content": "f(\\cdot)" + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "text", + "content": ", that is " + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "inline_equation", + "content": "(l = 1,2,3,\\dots,L)" + }, + { + "bbox": [ + 305, + 111, + 547, + 149 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 385, + 156, + 546, + 178 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 385, + 156, + 546, + 178 + ], + "spans": [ + { + "bbox": [ + 385, + 156, + 546, + 178 + ], + "type": "interline_equation", + "content": "\\boldsymbol {a} ^ {l} = f \\left(\\boldsymbol {W} ^ {l} \\boldsymbol {a} ^ {l - 1}\\right) \\tag {1}", + "image_path": "9b5e2d0fe679b32ce5c2d6355002257beaec245f72238b0178fa314210558232.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 186, + 533, + 198 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 186, + 533, + 198 + ], + "spans": [ + { + "bbox": [ + 305, + 186, + 533, + 198 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 186, + 533, + 198 + ], + "type": "inline_equation", + "content": "f(\\cdot)" + }, + { + "bbox": [ + 305, + 186, + 533, + 198 + ], + "type": "text", + "content": " is often set as the ReLU activation function." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 198, + 545, + 234 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 198, + 545, + 234 + ], + "spans": [ + { + "bbox": [ + 305, + 198, + 545, + 234 + ], + "type": "text", + "content": "In SNNs, the Integrate-and-Fire (IF) spiking neuron model is commonly used in ANN-to-SNN conversion [25, 2, 7]. The dynamics of the IF model are described by:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 330, + 241, + 546, + 258 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 330, + 241, + 546, + 258 + ], + "spans": [ + { + "bbox": [ + 330, + 241, + 546, + 258 + ], + "type": "interline_equation", + "content": "\\pmb {v} ^ {l} (t) = \\pmb {v} ^ {l} (t - 1) + \\pmb {W} ^ {l} \\theta^ {l - 1} \\pmb {s} ^ {l - 1} (t) - \\theta^ {l} \\pmb {s} ^ {l} (t) \\quad (2)", + "image_path": "e52bc72ac4a14b69de4e403f80f4bc81a81609b2d21cd9126d74063a604cb77c.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "spans": [ + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "inline_equation", + "content": "\\pmb{v}^l (t)" + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "text", + "content": " denotes the membrane potential of neurons in layer " + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "text", + "content": " at time step " + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "text", + "content": ", which corresponds to the linear transformation matrix " + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "inline_equation", + "content": "\\pmb{W}^{l}" + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "text", + "content": ", the threshold " + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "inline_equation", + "content": "\\theta^l" + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "text", + "content": ", and the binary output spikes of neurons in the previous layer " + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "inline_equation", + "content": "l - 1" + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "text", + "content": ", denoted as " + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "inline_equation", + "content": "\\pmb{s}^{l - 1}(t)" + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "text", + "content": ". The " + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "inline_equation", + "content": "s^l (t)" + }, + { + "bbox": [ + 305, + 265, + 546, + 326 + ], + "type": "text", + "content": " is defined as follows:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 376, + 335, + 546, + 352 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 376, + 335, + 546, + 352 + ], + "spans": [ + { + "bbox": [ + 376, + 335, + 546, + 352 + ], + "type": "interline_equation", + "content": "\\boldsymbol {s} ^ {l} (t) = H \\left(\\boldsymbol {u} ^ {l} (t) - \\theta^ {l}\\right) \\tag {3}", + "image_path": "aa48138a199551e53a172714e12c15eb863b7e92f18db63d82ce322ad58e3338.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "spans": [ + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "type": "inline_equation", + "content": "\\pmb{u}^{l}(t) = \\pmb{v}^{l}(t - 1) + \\pmb{W}^{l}\\theta^{l - 1}\\pmb{s}^{l - 1}(t)" + }, + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "type": "text", + "content": " denotes the membrane potential of neurons before the trigger of a spike at time step " + }, + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "type": "inline_equation", + "content": "H(\\cdot)" + }, + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "type": "text", + "content": " denotes the Heaviside step function. The neurons generate output spikes whenever the membrane potential " + }, + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "type": "inline_equation", + "content": "\\pmb{u}^{l}(t)" + }, + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "type": "text", + "content": " exceeds the threshold value " + }, + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "type": "inline_equation", + "content": "\\theta^l" + }, + { + "bbox": [ + 304, + 355, + 547, + 441 + ], + "type": "text", + "content": ", and the membrane potential is reset by subtracting the threshold value to reduce information loss [41]." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 450, + 443, + 463 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 450, + 443, + 463 + ], + "spans": [ + { + "bbox": [ + 306, + 450, + 443, + 463 + ], + "type": "text", + "content": "3.2.ANN-to-SNN conversion" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 469, + 545, + 542 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 469, + 545, + 542 + ], + "spans": [ + { + "bbox": [ + 304, + 469, + 545, + 542 + ], + "type": "text", + "content": "To achieve the ANN-SNN conversion, a relationship is established between the rectified linear unit (ReLU) activation of analog neurons in ANNs and the firing rate or postsynaptic potential of spiking neurons in SNNs. This is obtained by summing Eq. 2 from time step 1 to " + }, + { + "bbox": [ + 304, + 469, + 545, + 542 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 304, + 469, + 545, + 542 + ], + "type": "text", + "content": " dividing " + }, + { + "bbox": [ + 304, + 469, + 545, + 542 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 304, + 469, + 545, + 542 + ], + "type": "text", + "content": " on both sides, resulting in the following equation:" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 549, + 545, + 585 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 549, + 545, + 585 + ], + "spans": [ + { + "bbox": [ + 307, + 549, + 545, + 585 + ], + "type": "interline_equation", + "content": "\\frac {\\boldsymbol {v} ^ {l} (T) - \\boldsymbol {v} ^ {l} (0)}{T} = \\frac {\\sum_ {t = 1} ^ {T} \\boldsymbol {W} ^ {l} \\theta^ {l - 1} \\boldsymbol {s} ^ {l - 1} (t)}{T} - \\frac {\\sum_ {t = 1} ^ {T} \\theta^ {l} \\boldsymbol {s} ^ {l} (t)}{T} \\tag {4}", + "image_path": "1533c4ed28baa2caac88702969b0e075f8e111b88892409c0c7655f6aeca607d.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 585, + 545, + 625 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 585, + 545, + 625 + ], + "spans": [ + { + "bbox": [ + 304, + 585, + 545, + 625 + ], + "type": "text", + "content": "The linear relationship between " + }, + { + "bbox": [ + 304, + 585, + 545, + 625 + ], + "type": "inline_equation", + "content": "\\phi^l (T)" + }, + { + "bbox": [ + 304, + 585, + 545, + 625 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 585, + 545, + 625 + ], + "type": "inline_equation", + "content": "\\phi^{l - 1}(T)" + }, + { + "bbox": [ + 304, + 585, + 545, + 625 + ], + "type": "text", + "content": " is established by defining " + }, + { + "bbox": [ + 304, + 585, + 545, + 625 + ], + "type": "inline_equation", + "content": "\\phi^l (T) = \\frac{\\sum_{t\\equiv 1}^T\\theta^l s^l(t)}{T}" + }, + { + "bbox": [ + 304, + 585, + 545, + 625 + ], + "type": "text", + "content": " as the average postsynaptic potential:" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 343, + 632, + 545, + 658 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 343, + 632, + 545, + 658 + ], + "spans": [ + { + "bbox": [ + 343, + 632, + 545, + 658 + ], + "type": "interline_equation", + "content": "\\phi^ {l} (T) = \\boldsymbol {W} ^ {l} \\phi^ {l - 1} (T) - \\frac {\\boldsymbol {v} ^ {l} (T) - \\boldsymbol {v} ^ {l} (0)}{T} \\tag {5}", + "image_path": "9d6f0ab1568e62b5ad9cc102a5a38f57bcf7bbea67fdc4f2233b4bebb1ef8758.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 665, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 546, + 714 + ], + "type": "text", + "content": "The equivalence between Eq. 1 and 5 holds only as " + }, + { + "bbox": [ + 304, + 665, + 546, + 714 + ], + "type": "inline_equation", + "content": "\\mathrm{T}" + }, + { + "bbox": [ + 304, + 665, + 546, + 714 + ], + "type": "text", + "content": " goes to infinity, resulting in a conversion error. To address this issue, we replace the ReLU activation function with the quantization clip-floor-shift (QCFS) [2] function in the ANNs." + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1763" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 163, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 163, + 83 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 163, + 83 + ], + "type": "text", + "content": "3.3. Model Architecture" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 90, + 287, + 174 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 90, + 287, + 174 + ], + "spans": [ + { + "bbox": [ + 46, + 90, + 287, + 174 + ], + "type": "text", + "content": "An overview of the MST is depicted in Fig. 2, where the Swin Transformer [29] is adopted as the backbone network. To convert the original network into a fully-spiking manner, we incorporate the QCFS activation functions after each linear or regularization layer during the training phase, which are replaced with Integrate-and-Fire (IF) neurons in the inference process, resulting in more efficient computation." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 175, + 287, + 198 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 175, + 287, + 198 + ], + "spans": [ + { + "bbox": [ + 47, + 175, + 287, + 198 + ], + "type": "text", + "content": "The entire computation process in the spiking self-attention module can be formulated as:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 113, + 205, + 287, + 223 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 113, + 205, + 287, + 223 + ], + "spans": [ + { + "bbox": [ + 113, + 205, + 287, + 223 + ], + "type": "interline_equation", + "content": "Q _ {s p k} [ t ] = \\operatorname {I F} (X [ t ] * W _ {q}) \\tag {6}", + "image_path": "b8770a9a2dc1ac26fdffb2b2a6d5549aa281911191e3e878f422e9f56b003f45.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 115, + 220, + 220, + 235 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 115, + 220, + 220, + 235 + ], + "spans": [ + { + "bbox": [ + 115, + 220, + 220, + 235 + ], + "type": "interline_equation", + "content": "K _ {s p k} [ t ] = \\operatorname {I F} (X [ t ] * W _ {k})", + "image_path": "31fb24d755b86abeea1168099dd6f9360cbbaf650ca7de971005fa6865012999.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "spans": [ + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "inline_equation", + "content": "Q_{spk}" + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "inline_equation", + "content": "K_{spk}" + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "text", + "content": " denote the spike matrices of the query and key at " + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "text", + "content": " time step, " + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "inline_equation", + "content": "\\mathrm{IF}(\\cdot)" + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "text", + "content": " is the IF neuron function, " + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "inline_equation", + "content": "W_{q}" + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "inline_equation", + "content": "W_{k}" + }, + { + "bbox": [ + 47, + 242, + 287, + 289 + ], + "type": "text", + "content": " denote the corresponding weight matrices. Attention score is defined as:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 99, + 297, + 287, + 326 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 99, + 297, + 287, + 326 + ], + "spans": [ + { + "bbox": [ + 99, + 297, + 287, + 326 + ], + "type": "interline_equation", + "content": "A _ {s p k} [ t ] = \\operatorname {I F} \\left(\\frac {Q _ {s p k} [ t ] * K _ {s p k} ^ {T} [ t ]}{\\sqrt {d}}\\right) \\tag {7}", + "image_path": "7b133b01bfbf7a4e60e574d98f9e4b0f91d0661853425c94e183d122e41750c5.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 333, + 287, + 380 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 333, + 287, + 380 + ], + "spans": [ + { + "bbox": [ + 47, + 333, + 287, + 380 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 333, + 287, + 380 + ], + "type": "inline_equation", + "content": "A_{spk}" + }, + { + "bbox": [ + 47, + 333, + 287, + 380 + ], + "type": "text", + "content": " represents the spike matrix of the attention score calculated by the dot product of the query spike matrix and the key spike matrix, and " + }, + { + "bbox": [ + 47, + 333, + 287, + 380 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 47, + 333, + 287, + 380 + ], + "type": "text", + "content": " is a scaling factor equal to the feature dimension of a given attention head." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 59, + 380, + 269, + 393 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 380, + 269, + 393 + ], + "spans": [ + { + "bbox": [ + 59, + 380, + 269, + 393 + ], + "type": "text", + "content": "The calculation of LN and BN can be expressed by:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 111, + 401, + 287, + 430 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 401, + 287, + 430 + ], + "spans": [ + { + "bbox": [ + 111, + 401, + 287, + 430 + ], + "type": "interline_equation", + "content": "y = \\frac {x - \\operatorname {E} [ x ]}{\\sqrt {\\operatorname {V a r} [ x ] + \\epsilon}} * \\gamma + \\beta \\tag {8}", + "image_path": "8fc9f20565f8c58aa86f25d9bd5e62c80b8fcd0761f2645fc4341fd2d234f233.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "spans": [ + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "text", + "content": " denotes the input tensor to be normalized, " + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "inline_equation", + "content": "\\operatorname{E}[x]" + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "inline_equation", + "content": "\\operatorname{Var}[x]" + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "text", + "content": " represent the mean and variance of " + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "text", + "content": " is a small constant added to the variance for numerical stability, " + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "text", + "content": " are trainable scaling and bias parameters respectively, and " + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "inline_equation", + "content": "y" + }, + { + "bbox": [ + 47, + 437, + 287, + 498 + ], + "type": "text", + "content": " is the normalized output of the layer." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 498, + 287, + 570 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 498, + 287, + 570 + ], + "spans": [ + { + "bbox": [ + 46, + 498, + 287, + 570 + ], + "type": "text", + "content": "In LN, the mean and variance are calculated across the features of each sample in a batch. Therefore, each sample in the batch has its normalization parameters. On the other hand, BN calculates the mean and variance across all samples in a batch for each feature, which means the normalization parameters are shared across all samples in a batch." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "type": "text", + "content": "Normalization is important for ensuring the feasibility of ANN-to-SNN conversion. As illustrated in Fig. 3, different normalization approach results in vastly different membrane potential in the inference process. Normalizing along the channel dimension (LN) cause a distribution mismatch between ANN and SNN, which leads to performance degradation, while normalizing along the batch dimension (BN) preserves a similar result. Replace all LN layers with BN layers is a straightforward approach to normalize the post-activation distribution of ANNs during the conversion process, but for large datasets like ImageNet, there are convergence issues. We resolve this problem by simply adding" + } + ] + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 310, + 69, + 382, + 143 + ], + "blocks": [ + { + "bbox": [ + 310, + 69, + 382, + 143 + ], + "lines": [ + { + "bbox": [ + 310, + 69, + 382, + 143 + ], + "spans": [ + { + "bbox": [ + 310, + 69, + 382, + 143 + ], + "type": "image", + "image_path": "a576c5b44bc04911a17c4c203092f13c8b8f878f5651da5977efa40b9de7a87c.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 334, + 144, + 357, + 152 + ], + "lines": [ + { + "bbox": [ + 334, + 144, + 357, + 152 + ], + "spans": [ + { + "bbox": [ + 334, + 144, + 357, + 152 + ], + "type": "text", + "content": "(a) ANN" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 385, + 70, + 459, + 143 + ], + "blocks": [ + { + "bbox": [ + 385, + 70, + 459, + 143 + ], + "lines": [ + { + "bbox": [ + 385, + 70, + 459, + 143 + ], + "spans": [ + { + "bbox": [ + 385, + 70, + 459, + 143 + ], + "type": "image", + "image_path": "b2ecc446fa9bf249c908ea65e9e95e622ec7ef559cc58188a2d15b59bdc0849f.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 403, + 144, + 438, + 152 + ], + "lines": [ + { + "bbox": [ + 403, + 144, + 438, + 152 + ], + "spans": [ + { + "bbox": [ + 403, + 144, + 438, + 152 + ], + "type": "text", + "content": "(b) SNN (BN)" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 461, + 70, + 544, + 143 + ], + "blocks": [ + { + "bbox": [ + 461, + 70, + 544, + 143 + ], + "lines": [ + { + "bbox": [ + 461, + 70, + 544, + 143 + ], + "spans": [ + { + "bbox": [ + 461, + 70, + 544, + 143 + ], + "type": "image", + "image_path": "c99baa9b30e33ed9725b32faf7db4c5e59e8340b2b9906af866793d3ee425de7.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 482, + 144, + 518, + 152 + ], + "lines": [ + { + "bbox": [ + 482, + 144, + 518, + 152 + ], + "spans": [ + { + "bbox": [ + 482, + 144, + 518, + 152 + ], + "type": "text", + "content": "(b) SNN (LN)" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 304, + 164, + 547, + 232 + ], + "lines": [ + { + "bbox": [ + 304, + 164, + 547, + 232 + ], + "spans": [ + { + "bbox": [ + 304, + 164, + 547, + 232 + ], + "type": "text", + "content": "Figure 3. Illustration of distributions of (a) post-activation distribution in ANN, and (b-c) cumulative membrane potential distributions of SNN model with BN and LN, respectively. The heatmap shows a similar distribution between ANN and SNN(BN) models, while the widely varying distribution between ANN and SNN(LN) models leads to performance degradation." + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 242, + 546, + 277 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 242, + 546, + 277 + ], + "spans": [ + { + "bbox": [ + 304, + 242, + 546, + 277 + ], + "type": "text", + "content": "a BN layer after each linear layer in the MLP module, inspired by [53]. Mathematically, the first layer of the modified MLP module is formulated as follows:" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 359, + 287, + 545, + 300 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 359, + 287, + 545, + 300 + ], + "spans": [ + { + "bbox": [ + 359, + 287, + 545, + 300 + ], + "type": "interline_equation", + "content": "\\operatorname {M L P} (x) = \\operatorname {I F} (\\operatorname {L i n e a r} (\\operatorname {B N} (x))) \\tag {9}", + "image_path": "215b699c4d5ba33c8fe3b572f0165b1e22b8ab1b966e9f27b35108400f1ab273.jpg" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 310, + 546, + 358 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 310, + 546, + 358 + ], + "spans": [ + { + "bbox": [ + 304, + 310, + 546, + 358 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 310, + 546, + 358 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 304, + 310, + 546, + 358 + ], + "type": "text", + "content": " represents the input tensor, Linear denotes the linear layer, BN represents the batch normalization layer. Notably, the MLP module consists of two linear layers, each followed by a BN layer and an IF neuron function." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 306, + 371, + 481, + 384 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 371, + 481, + 384 + ], + "spans": [ + { + "bbox": [ + 306, + 371, + 481, + 384 + ], + "type": "text", + "content": "3.4. Random Spike Masking Method" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 304, + 390, + 545, + 449 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 390, + 545, + 449 + ], + "spans": [ + { + "bbox": [ + 304, + 390, + 545, + 449 + ], + "type": "text", + "content": "Implementing the Transformer in SNNs using the ANN-to-SNN conversion method presents a challenge due to the high power consumption demand. To address this issue, we propose the Random Spike Masking (RSM) method for reducing redundant spikes during inference." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 304, + 449, + 546, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 449, + 546, + 533 + ], + "spans": [ + { + "bbox": [ + 304, + 449, + 546, + 533 + ], + "type": "text", + "content": "Traditional ANN pruning methods remove weights with low magnitudes, which are believed to have little impact on the final output of the model [58]. In contrast, our RSM method prunes input spikes randomly according to the masking ratio, where each spike " + }, + { + "bbox": [ + 304, + 449, + 546, + 533 + ], + "type": "inline_equation", + "content": "(s = 1)" + }, + { + "bbox": [ + 304, + 449, + 546, + 533 + ], + "type": "text", + "content": " has the probability of turning into a failure state " + }, + { + "bbox": [ + 304, + 449, + 546, + 533 + ], + "type": "inline_equation", + "content": "(s = 0)" + }, + { + "bbox": [ + 304, + 449, + 546, + 533 + ], + "type": "text", + "content": " that can be implemented using binary mask matrices." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 304, + 534, + 546, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 534, + 546, + 676 + ], + "spans": [ + { + "bbox": [ + 304, + 534, + 546, + 676 + ], + "type": "text", + "content": "It is important to note that our proposed RSM method for spike pruning in SNNs differs from Dropout [44] used in ANNs. Dropout is a regularization technique that randomly masks some neurons during training, but all neurons are used for inference, and the output needs to be scaled by the retained probability used during training. This means that Dropout cannot directly reduce the number of spikes in the network. Unlike Dropout, the RSM method reduces the computational cost of SNNs by randomly pruning input spikes in both training and inference, explicitly removing redundancy in input spikes while obtaining excellent performance." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 304, + 677, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 547, + 713 + ], + "type": "text", + "content": "The RSM method, illustrated in Fig. 2(c-e), randomly generates a binary mask with the same shape as the input spike matrix based on the masking ratio. This determines" + } + ] + } + ], + "index": 27 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1764" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 58, + 72, + 536, + 518 + ], + "blocks": [ + { + "bbox": [ + 58, + 72, + 536, + 518 + ], + "lines": [ + { + "bbox": [ + 58, + 72, + 536, + 518 + ], + "spans": [ + { + "bbox": [ + 58, + 72, + 536, + 518 + ], + "type": "table", + "html": "
DatasetModelMethodArchitecture#Param(M)Time StepsAccuracy(%)
CIFAR-10ANN [29]Direct TrainingSwin-T(BN)27.6/98.14
Diet-SNN [39]Direct TrainingVGG-1639.91093.44
tdBN [56]Direct TrainingResNet-1912.6492.92
TET [6]Direct TrainingResNet-1912.6694.50
DSR [32]Direct TrainingPreActResNet-1811.22095.40
Spikformer [57]Direct TrainingSpikformer-4-3849.3495.51
RMP [13]ANN-to-SNNVGG-1639.9204893.63
RNL [7]ANN-to-SNNPreActResNet-1811.225693.45
QCFS [2]ANN-to-SNNRestNet-1811.751296.06
MST (ours)ANN-to-SNNSwin-T(BN)27.66496.32
12897.06
25697.27
CIFAR-100ANN [29]Direct TrainingSwin-T(BN)27.6/88.72
Diet-SNN [39]Direct TrainingVGG-1639.9569.67
tdBN [56]Direct TrainingResNet-1912.6470.86
TET [6]Direct TrainingResNet-1912.6674.72
DSR [32]Direct TrainingPreActResNet-1811.22078.50
SpikformerDirect TrainingSpikformer-4-3849.3478.21
RMP [13]ANN-to-SNNVGG-1639.9204870.93
RNL [7]ANN-to-SNNPreActResNet-1811.225675.10
QCFS [2]ANN-to-SNNRestNet-1811.751279.61
MST (ours)ANN-to-SNNSwin-T(BN)27.66485.40
12886.73
25686.91
ImageNetANN [29]Direct TrainingSwin-T(BN)28.5/80.51
Diet-SNN [39]Direct TrainingVGG-1639.9569.00
tdBN [56]Direct TrainingSEW-ResNet-3421.8467.04
TET [6]Direct TrainingSEW-ResNet-3421.8468.00
DSR [32]Direct TrainingPreActResNet-1811.25067.74
Spikformer [57]Direct TrainingSpikformer-8-76866.3474.81
RMP [13]ANN-to-SNNVGG-1639.9204873.09
QCFS [2]ANN-to-SNNRestNet-1811.7102474.32
MST (ours)ANN-to-SNNSwin-T(BN)28.512877.88
25678.37
51278.51
", + "image_path": "31d314a5100e770ca4f88c65c8bcc9e4282282103df0c7e2aafd93ecf1c2605b.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 46, + 520, + 545, + 544 + ], + "lines": [ + { + "bbox": [ + 46, + 520, + 545, + 544 + ], + "spans": [ + { + "bbox": [ + 46, + 520, + 545, + 544 + ], + "type": "text", + "content": "Table 1. Performance comparison between the proposed model and the SOTA models on different static datasets, where Swin-T (BN) refers to the self-implemented ANN baseline replacing LN with BN [29]." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 562, + 288, + 646 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 562, + 288, + 646 + ], + "spans": [ + { + "bbox": [ + 46, + 562, + 288, + 646 + ], + "type": "text", + "content": "which spikes are transmitted for calculation in subsequent neurons, enabling high matrix sparsity. With a masking ratio of " + }, + { + "bbox": [ + 46, + 562, + 288, + 646 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 46, + 562, + 288, + 646 + ], + "type": "text", + "content": ", for example, each spike has a " + }, + { + "bbox": [ + 46, + 562, + 288, + 646 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 46, + 562, + 288, + 646 + ], + "type": "text", + "content": " chance of being masked, reducing the number of spikes and power consumption. Hence, combining both the SNN-based self-attention mechanism with the RSM approach promises a balance between performance and energy efficiency." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 657, + 128, + 671 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 657, + 128, + 671 + ], + "spans": [ + { + "bbox": [ + 47, + 657, + 128, + 671 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 288, + 715 + ], + "type": "text", + "content": "We conduct extensive experiments on both static datasets including CIFAR-10 [22], CIFAR-100 [21], and ImageNet datasets [5], and neuromorphic datasets including" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 562, + 545, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 562, + 545, + 647 + ], + "spans": [ + { + "bbox": [ + 304, + 562, + 545, + 647 + ], + "type": "text", + "content": "CIFAR10-DVS [24], N-Caltech101 [37], N-Cars [43], ActionRecognition [33], and ASL-DVS [1] datasets, to validate the effectiveness of the MST model. In addition, we evaluate the effect of the RSM approach on accuracy and energy efficiency using the SpikingJelly framework [9]. More details of the training can be found in the supplementary." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 658, + 474, + 670 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 658, + 474, + 670 + ], + "spans": [ + { + "bbox": [ + 306, + 658, + 474, + 670 + ], + "type": "text", + "content": "4.1. Performance on Static Datasets" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 677, + 545, + 713 + ], + "type": "text", + "content": "Tab. 1 presents a comprehensive comparison of the MST model with the current SOTA SNN models on the CIFAR-10/100 and ImageNet datasets. The results show that the" + } + ] + } + ], + "index": 7 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 749, + 315, + 757 + ], + "type": "text", + "content": "1765" + } + ] + } + ], + "index": 8 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 63, + 71, + 272, + 178 + ], + "blocks": [ + { + "bbox": [ + 63, + 71, + 272, + 178 + ], + "lines": [ + { + "bbox": [ + 63, + 71, + 272, + 178 + ], + "spans": [ + { + "bbox": [ + 63, + 71, + 272, + 178 + ], + "type": "image", + "image_path": "b248ac5f83f67e1ee1b66ea3bbda47e970d97ba5aa8f1d281ea3df34d55f2ba3.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 61, + 190, + 271, + 201 + ], + "lines": [ + { + "bbox": [ + 61, + 190, + 271, + 201 + ], + "spans": [ + { + "bbox": [ + 61, + 190, + 271, + 201 + ], + "type": "text", + "content": "Figure 4. Model Architecture for Neuromorphic Datasets." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 221, + 286, + 245 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 221, + 286, + 245 + ], + "spans": [ + { + "bbox": [ + 46, + 221, + 286, + 245 + ], + "type": "text", + "content": "proposed MST model outperforms all other models in terms of top-1 accuracy on all three datasets." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 245, + 286, + 304 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 245, + 286, + 304 + ], + "spans": [ + { + "bbox": [ + 46, + 245, + 286, + 304 + ], + "type": "text", + "content": "Direct training models, such as Diet-SNN [39], tdBN [56], TET [6], and DSR [32], require lower time steps, but their top-1 accuracy is relatively low, compared to that of the MST model, in which tdBN [56] is " + }, + { + "bbox": [ + 46, + 245, + 286, + 304 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 46, + 245, + 286, + 304 + ], + "type": "text", + "content": " less accurate on the CIFAR-100 and ImageNet datasets." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 305, + 286, + 400 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 305, + 286, + 400 + ], + "spans": [ + { + "bbox": [ + 46, + 305, + 286, + 400 + ], + "type": "text", + "content": "Conversely, models employing the ANN-to-SNN conversion method typically necessitate a greater number of time steps to reach optimal performance, including RMP [13], RNL [7], and QCFS [2]. The MST model also employs this method but requires only 64 time steps to achieve superior performance, which is far fewer than RMP [13]. This suggests that the MST model can achieve the highest accuracy in a reasonable number of time steps." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 401, + 286, + 496 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 401, + 286, + 496 + ], + "spans": [ + { + "bbox": [ + 46, + 401, + 286, + 496 + ], + "type": "text", + "content": "Compared to transformer-based SNN models such as Spikformer [57], the MST model achieves higher top-1 accuracy on all three datasets. Specifically, the top-1 accuracy of the MST model is " + }, + { + "bbox": [ + 46, + 401, + 286, + 496 + ], + "type": "inline_equation", + "content": "1.8\\%" + }, + { + "bbox": [ + 46, + 401, + 286, + 496 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 401, + 286, + 496 + ], + "type": "inline_equation", + "content": "8.7\\%" + }, + { + "bbox": [ + 46, + 401, + 286, + 496 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 401, + 286, + 496 + ], + "type": "inline_equation", + "content": "3.7\\%" + }, + { + "bbox": [ + 46, + 401, + 286, + 496 + ], + "type": "text", + "content": " higher than Spikformer on the CIFAR-10, CIFAR-100, and ImageNet datasets, respectively. Moreover, the MST model has significantly fewer parameters compared to the 8-layer Spikformer [57] model." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 503, + 258, + 517 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 503, + 258, + 517 + ], + "spans": [ + { + "bbox": [ + 47, + 503, + 258, + 517 + ], + "type": "text", + "content": "4.2. Performance on Neuromorphic Datasets" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 522, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 522, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 46, + 522, + 286, + 712 + ], + "type": "text", + "content": "We showcase the suitability of the MST model for processing event-based data by evaluating its performance on neuromorphic datasets. Fig. 4 shows the framework for the MST model to process the neuromorphic datasets. We utilize a frame-based representation for preprocessing, where the event streams are transformed into a sequence of high-rate frames. Each event in the stream consists of four dimensions, including two spatial coordinates (x, y), timestamp, and polarity. The frames are integrated into an input tensor of size " + }, + { + "bbox": [ + 46, + 522, + 286, + 712 + ], + "type": "inline_equation", + "content": "(\\mathrm{n}\\times \\mathrm{C},\\mathrm{H},\\mathrm{W})" + }, + { + "bbox": [ + 46, + 522, + 286, + 712 + ], + "type": "text", + "content": " ,where n is the number of frames, C is the number of original channels (which equals two, representing polarity), and H and W represent the height and width of the input, respectively. To align the input dimension with the model, an additional reduction layer is added to the first layer of the entire model, which reduces the channel dimension to 3. This enables us" + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 316, + 71, + 537, + 490 + ], + "blocks": [ + { + "bbox": [ + 316, + 71, + 537, + 490 + ], + "lines": [ + { + "bbox": [ + 316, + 71, + 537, + 490 + ], + "spans": [ + { + "bbox": [ + 316, + 71, + 537, + 490 + ], + "type": "table", + "html": "
DatasetModelTime StepsAccuracy (%)
CIFAR10-DVSSwin-T (BN)/88.98
TA-SNN [52]1072.00
PLIF [11]2074.80
Dspkie [26]1075.40
DSR [32]1077.30
TET [6]1083.17
NDA [27]1081.70
Spikformer [57]1080.90
12886.60
MST (ours)25687.20
51288.12
N-CALTECH101Swin-T (BN)/92.00
SALT [19]2055.00
NDA [27]1083.70
6484.71
MST (ours)12889.42
25691.38
N-CARSSwin-T (BN)/97.14
CarSNN [48]1086.00
NDA [27]1091.90
3294.67
MST (ours)6496.58
12897.28
Action RecognitionSwin-T (BN)/90.14
STCA [12]1071.20
Mb-SNN [28]1078.10
6484.76
MST (ours)12886.92
25688.21
ASL-DVSSwin-T (BN)/99.90
Meta-SNN [45]10096.04
6498.04
MST (ours)12898.51
25699.10
", + "image_path": "f62b731f80bd232d234581ecd081d07909b7de8d58f457da747a491af8a1eb9f.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 491, + 545, + 514 + ], + "lines": [ + { + "bbox": [ + 306, + 491, + 545, + 514 + ], + "spans": [ + { + "bbox": [ + 306, + 491, + 545, + 514 + ], + "type": "text", + "content": "Table 2. Performance comparison between the proposed model and the SOTA models on different neuromorphic datasets." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 528, + 545, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 528, + 545, + 601 + ], + "spans": [ + { + "bbox": [ + 304, + 528, + 545, + 601 + ], + "type": "text", + "content": "to leverage pre-training weights from the ImageNet dataset, accelerating the training convergence. Data augmentation for SNNs [27] is also applied to improve the accuracy. The ensuing experimental results demonstrate that the proposed fine-tuning approach for ANN-to-SNN conversion achieves remarkably high accuracy." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 602, + 545, + 698 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 602, + 545, + 698 + ], + "spans": [ + { + "bbox": [ + 304, + 602, + 545, + 698 + ], + "type": "text", + "content": "The experimental results presented in Tab. 2 demonstrate the effectiveness of the proposed MST model in processing neuromorphic datasets. We compare the MST model with several SOTA SNN models on five popular neuromorphic datasets, including CIFAR10-DVS, N-Caltech101, NCars, Action Recognition, and ASL-DVS dataset. The experimental results show that the MST model achieves the highest top-1 accuracy on all datasets." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 317, + 701, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 701, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 317, + 701, + 545, + 712 + ], + "type": "text", + "content": "CIFAR10-DVS, N-Caltech101, and N-Cars datasets are" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 749, + 315, + 757 + ], + "type": "text", + "content": "1766" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "text", + "content": "constructed by converting the static datasets into event data by using event-based cameras. Tab. 2 shows that the MST model outperforms other SOTA SNN models significantly, achieving improvements of " + }, + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "inline_equation", + "content": "4.95\\%" + }, + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "inline_equation", + "content": "7.68\\%" + }, + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "inline_equation", + "content": "5.38\\%" + }, + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "text", + "content": " on CIFAR10-DVS, N-Caltech101, and N-Cars, respectively. The Action Recognition dataset consists of a series of human actions captured by event-based cameras. By adopting the data preprocessing method of [20], our MST model achieves a top-1 accuracy of " + }, + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "inline_equation", + "content": "88.21\\%" + }, + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "text", + "content": ", which is far higher than other models. Additionally, the ASL-DVS dataset is a large 24-class dataset of gestures and the experimental results demonstrate that our MST model outperforms other SOTA models by " + }, + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "inline_equation", + "content": "3.06\\%" + }, + { + "bbox": [ + 46, + 72, + 289, + 228 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 228, + 288, + 264 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 228, + 288, + 264 + ], + "spans": [ + { + "bbox": [ + 47, + 228, + 288, + 264 + ], + "type": "text", + "content": "These results highlight the effectiveness of our proposed MST model in processing various types of neuromorphic datasets." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 274, + 288, + 299 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 274, + 288, + 299 + ], + "spans": [ + { + "bbox": [ + 47, + 274, + 288, + 299 + ], + "type": "text", + "content": "4.3. Effectiveness of the Random Spike Masking Method" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 304, + 287, + 365 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 304, + 287, + 365 + ], + "spans": [ + { + "bbox": [ + 46, + 304, + 287, + 365 + ], + "type": "text", + "content": "The ANN-to-SNN conversion method typically involves a large number of time steps, leading to high power consumption. To address this issue, we propose the RSM method for spike pruning, and we demonstrate its effectiveness in the following section." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 365, + 287, + 484 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 365, + 287, + 484 + ], + "spans": [ + { + "bbox": [ + 46, + 365, + 287, + 484 + ], + "type": "text", + "content": "Drawing inspiration from knowledge distillation [16], we use the model without masked as a teacher model, and the model after masked as a student model. By fine-tuning the student model, the masked model achieves high performance comparable to the original model without masking in terms of accuracy. This finding highlights the efficacy of the knowledge distillation technique in training masked models without compromising their performance. Consequently, we employ the fine-tuning approach as the training method for our subsequent comparative analysis." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 485, + 287, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 485, + 287, + 568 + ], + "spans": [ + { + "bbox": [ + 46, + 485, + 287, + 568 + ], + "type": "text", + "content": "We evaluate the RSM method in two critical modules in the Transformer: the self-attention (SA) module and the Multi-layer Perceptron (MLP) module. As shown in Fig. 2(d-e), we apply the RSM method to the Query, Key, and Attention matrices in the SA module, as well as the output spike matrix of the first fully connected layer within each block of the MLP module." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 288, + 714 + ], + "type": "text", + "content": "Fig. 5(a) and (b) depict the variation in accuracy for different masking ratios on the CIFAR-10 and CIFAR-100 datasets, respectively. The experimental results demonstrate that the accuracy decreases with the increasing masking ratio for both the SA and MLP modules, but their sensitivity to masking ratio changes differs. Specifically, the accuracy of the SA module remains stable over a certain range of masking ratios. In contrast, the accuracy of the MLP module declines more sharply and is more sensitive to masking ratio changes. Consistent with prior research [34, 49], the redundancy in the SA module enables the MST to withstand the losses caused by missing input spikes with" + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 310, + 72, + 423, + 186 + ], + "blocks": [ + { + "bbox": [ + 310, + 72, + 423, + 186 + ], + "lines": [ + { + "bbox": [ + 310, + 72, + 423, + 186 + ], + "spans": [ + { + "bbox": [ + 310, + 72, + 423, + 186 + ], + "type": "image", + "image_path": "6faf2ceee2114643d5131e26d5123b257fa82443ebfe7cc4e72df0ed9dc2610b.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 311, + 186, + 423, + 297 + ], + "blocks": [ + { + "bbox": [ + 311, + 186, + 423, + 297 + ], + "lines": [ + { + "bbox": [ + 311, + 186, + 423, + 297 + ], + "spans": [ + { + "bbox": [ + 311, + 186, + 423, + 297 + ], + "type": "image", + "image_path": "33a1b502007c475da3927f56b6ae28b7631c937ae34c98efc8d03ceb58f21856.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 427, + 72, + 541, + 186 + ], + "blocks": [ + { + "bbox": [ + 427, + 72, + 541, + 186 + ], + "lines": [ + { + "bbox": [ + 427, + 72, + 541, + 186 + ], + "spans": [ + { + "bbox": [ + 427, + 72, + 541, + 186 + ], + "type": "image", + "image_path": "ba202c8b34f3612eaad0b9798d9017e973b81cd93626f5adc0bc5c8fa0356297.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 433, + 186, + 541, + 297 + ], + "blocks": [ + { + "bbox": [ + 433, + 186, + 541, + 297 + ], + "lines": [ + { + "bbox": [ + 433, + 186, + 541, + 297 + ], + "spans": [ + { + "bbox": [ + 433, + 186, + 541, + 297 + ], + "type": "image", + "image_path": "12937ad9b9a231509fed4aa82780f80d28c533b529eb6c6516ed611f8811ca20.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 317, + 365, + 535, + 500 + ], + "blocks": [ + { + "bbox": [ + 305, + 308, + 547, + 363 + ], + "lines": [ + { + "bbox": [ + 305, + 308, + 547, + 363 + ], + "spans": [ + { + "bbox": [ + 305, + 308, + 547, + 363 + ], + "type": "text", + "content": "Figure 5. The effectiveness of the RSM method in (a) SA and (b) MLP modules of the MST model, as well as in Spiking (c) ResNet-18 and (d) VGG-16 models, with varying masking ratios. The inset photographs show the standard deviation of accuracy in 10 runs." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 317, + 365, + 535, + 500 + ], + "lines": [ + { + "bbox": [ + 317, + 365, + 535, + 500 + ], + "spans": [ + { + "bbox": [ + 317, + 365, + 535, + 500 + ], + "type": "image", + "image_path": "23340100e6adda5fbff85a8e0a895c1b4f79f391baadfe93e070b1d9cd97309e.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 511, + 545, + 533 + ], + "lines": [ + { + "bbox": [ + 305, + 511, + 545, + 533 + ], + "spans": [ + { + "bbox": [ + 305, + 511, + 545, + 533 + ], + "type": "text", + "content": "Figure 6. Comparison of the accuracy of masking different numbers of blocks on the CIFAR-100 dataset." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 543, + 545, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 543, + 545, + 567 + ], + "spans": [ + { + "bbox": [ + 305, + 543, + 545, + 567 + ], + "type": "text", + "content": "out significantly affecting the overall performance of the SNN." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 568, + 545, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 568, + 545, + 676 + ], + "spans": [ + { + "bbox": [ + 304, + 568, + 545, + 676 + ], + "type": "text", + "content": "In addition to the variation in sensitivity to changes in the masking ratio between different modules, our experiments also demonstrate that the sensitivity can vary depending on the dataset used. The CIFAR-10 dataset is relatively less sensitive to changes in the masking ratio, with only a " + }, + { + "bbox": [ + 304, + 568, + 545, + 676 + ], + "type": "inline_equation", + "content": "0.1\\%" + }, + { + "bbox": [ + 304, + 568, + 545, + 676 + ], + "type": "text", + "content": " decrease in accuracy when the masking ratio reaches " + }, + { + "bbox": [ + 304, + 568, + 545, + 676 + ], + "type": "inline_equation", + "content": "80\\%" + }, + { + "bbox": [ + 304, + 568, + 545, + 676 + ], + "type": "text", + "content": ". In contrast, the CIFAR-100 dataset is more sensitive to changes in the masking ratio, experiencing a more substantial accuracy decline as the masking ratio increases." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 677, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 715 + ], + "type": "text", + "content": "We also investigate the potential of the RSM method as a general approach for reducing power consumption in the context of ANN-to-SNN conversion. By applying the RSM" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1767" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 72, + 295, + 205 + ], + "blocks": [ + { + "bbox": [ + 48, + 72, + 295, + 205 + ], + "lines": [ + { + "bbox": [ + 48, + 72, + 295, + 205 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 295, + 205 + ], + "type": "table", + "html": "
ModelRandom RatioP (α Watts)Accuracy (%)
MST0%3.9G (×1)97.27 (+0)
50%3.2G (×0.82)97.25 (-0.02)
75%2.9G (×0.74)97.29 (+0.02)
ResNet-180%58.2M (×1)96.48 (+0)
50%40.7M (×0.70)92.88 (-3.60)
75%34.1M (×0.58)82.68 (-13.80)
VGG-160%24.4M (×1)95.46 (+0)
50%18.9M (×0.77)89.56 (-5.90)
75%16.7M (×0.68)79.09 (-16.37)
", + "image_path": "0c76c4745d76bc341e791b408da8cadc814b3a01707cbef862c2cfea8c827d8f.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "lines": [ + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "spans": [ + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "type": "text", + "content": "Table 3. Comparison of power consumption and accuracy between models with a Masking ratio of " + }, + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "type": "inline_equation", + "content": "0\\%" + }, + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "type": "text", + "content": " on the CIFAR-10 dataset, respectively. " + }, + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "type": "inline_equation", + "content": "(\\dots)" + }, + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "type": "text", + "content": " in the table denotes the power consumption/accuracy compared to the unmasked model (with " + }, + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "type": "inline_equation", + "content": "0\\%" + }, + { + "bbox": [ + 46, + 213, + 287, + 268 + ], + "type": "text", + "content": " random ratio)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 279, + 287, + 387 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 279, + 287, + 387 + ], + "spans": [ + { + "bbox": [ + 46, + 279, + 287, + 387 + ], + "type": "text", + "content": "method to other SNN models like Spiking ResNet-18 and VGG-16 and introducing a masking ratio to each convolution layer, we aim to decrease the transmitted spikes. Our results, presented in Fig. 5, demonstrate that the redundancy of these models can also be leveraged to maintain performance while reducing power consumption within a specific range. This indicates the potential of the RSM method for widespread applications in various SNN models for improving energy efficiency." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "spans": [ + { + "bbox": [ + 46, + 388, + 287, + 495 + ], + "type": "text", + "content": "Fig. 6 illustrates the impact of masking different numbers of blocks on the accuracy of the MST model. Our results indicate a non-linear, positive relationship between the number of masked blocks and performance loss. Notably, masking the first 2-5 blocks causes a slight performance loss, and the loss increases with more masked blocks until saturation at around 9-10 blocks. These observations provide valuable insights for designing partially masked blocks." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 495, + 287, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 495, + 287, + 567 + ], + "spans": [ + { + "bbox": [ + 46, + 495, + 287, + 567 + ], + "type": "text", + "content": "To better evaluate the effects of the RSM method on energy consumption reduction, we utilize theoretical estimates of energy consumption on neuromorphic chips based on previous studies [4, 7]. Assuming that a spike activity consumes " + }, + { + "bbox": [ + 46, + 495, + 287, + 567 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 46, + 495, + 287, + 567 + ], + "type": "text", + "content": " Joules and 1 time step takes " + }, + { + "bbox": [ + 46, + 495, + 287, + 567 + ], + "type": "inline_equation", + "content": "1\\mathrm{ms}" + }, + { + "bbox": [ + 46, + 495, + 287, + 567 + ], + "type": "text", + "content": ". Then the power model is defined as:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 104, + 577, + 287, + 601 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 104, + 577, + 287, + 601 + ], + "spans": [ + { + "bbox": [ + 104, + 577, + 287, + 601 + ], + "type": "interline_equation", + "content": "P = \\frac {\\text {t o t a l s p i k e s}}{1 \\times 1 0 ^ {- 3}} \\times \\alpha (\\text {W a t t s}) \\tag {10}", + "image_path": "a8dd18363d3e9f3d2fd2109224cda69f8b24844b389a9595b8586fc5c15a582e.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "text", + "content": "Tab. 3 presents the power consumption and accuracy of the MST, ResNet-18, and VGG-16 at " + }, + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "inline_equation", + "content": "0\\%" + }, + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 46, + 617, + 288, + 714 + ], + "type": "text", + "content": " masking ratios on the CIFAR-10 dataset. The RSM method is applied to the SA module in the MST and each block in ResNet-18 and VGG-16. The results demonstrate that the RSM method has a direct effect on the number of spikes transmitted, which in turn reduces power consumption. In specific, applying the RSM method to the MST" + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 309, + 69, + 541, + 194 + ], + "blocks": [ + { + "bbox": [ + 309, + 69, + 541, + 194 + ], + "lines": [ + { + "bbox": [ + 309, + 69, + 541, + 194 + ], + "spans": [ + { + "bbox": [ + 309, + 69, + 541, + 194 + ], + "type": "image", + "image_path": "d1263df0a69bbd320b189d3a5abc5227b2d808365ee9953a28f2c382fe0f240f.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 203, + 545, + 237 + ], + "lines": [ + { + "bbox": [ + 305, + 203, + 545, + 237 + ], + "spans": [ + { + "bbox": [ + 305, + 203, + 545, + 237 + ], + "type": "text", + "content": "Figure 7. Comparison of attention maps between the MST model with " + }, + { + "bbox": [ + 305, + 203, + 545, + 237 + ], + "type": "inline_equation", + "content": "0\\%" + }, + { + "bbox": [ + 305, + 203, + 545, + 237 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 305, + 203, + 545, + 237 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 305, + 203, + 545, + 237 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 305, + 203, + 545, + 237 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 305, + 203, + 545, + 237 + ], + "type": "text", + "content": " masking ratio (from top to bottom) with 5 different time steps." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 248, + 545, + 357 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 248, + 545, + 357 + ], + "spans": [ + { + "bbox": [ + 304, + 248, + 545, + 357 + ], + "type": "text", + "content": "model can reduce power consumption by " + }, + { + "bbox": [ + 304, + 248, + 545, + 357 + ], + "type": "inline_equation", + "content": "26.8\\%" + }, + { + "bbox": [ + 304, + 248, + 545, + 357 + ], + "type": "text", + "content": " without any loss in performance when the masking ratio reaches " + }, + { + "bbox": [ + 304, + 248, + 545, + 357 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 304, + 248, + 545, + 357 + ], + "type": "text", + "content": ". This finding suggests that there exist substantial redundant spikes in the SA module that can be pruned for better energy efficiency. As for ResNet-18 and VGG-16, the RSM method also yields significant power reduction. For instance, ResNet-18 can reduce power consumption by " + }, + { + "bbox": [ + 304, + 248, + 545, + 357 + ], + "type": "inline_equation", + "content": "30.1\\%" + }, + { + "bbox": [ + 304, + 248, + 545, + 357 + ], + "type": "text", + "content": " with a moderate accuracy loss of " + }, + { + "bbox": [ + 304, + 248, + 545, + 357 + ], + "type": "inline_equation", + "content": "3.6\\%" + }, + { + "bbox": [ + 304, + 248, + 545, + 357 + ], + "type": "text", + "content": ". However, excessive masking leads to a significant drop in accuracy." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 357, + 545, + 439 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 357, + 545, + 439 + ], + "spans": [ + { + "bbox": [ + 304, + 357, + 545, + 439 + ], + "type": "text", + "content": "In summary, our results demonstrate that the proposed RSM method is effective when applied to the SA module in the Transformer, as well as other SNN models. By eliminating redundant spikes, the RSM method reduces power consumption while preserving performance, making it a promising approach for energy-efficient ANN-to-SNN conversion." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 441, + 545, + 573 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 441, + 545, + 573 + ], + "spans": [ + { + "bbox": [ + 304, + 441, + 545, + 573 + ], + "type": "text", + "content": "To visualize the impact of different masking ratios on attention maps, we compared the models with " + }, + { + "bbox": [ + 304, + 441, + 545, + 573 + ], + "type": "inline_equation", + "content": "0\\%" + }, + { + "bbox": [ + 304, + 441, + 545, + 573 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 441, + 545, + 573 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 304, + 441, + 545, + 573 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 441, + 545, + 573 + ], + "type": "inline_equation", + "content": "75\\%" + }, + { + "bbox": [ + 304, + 441, + 545, + 573 + ], + "type": "text", + "content": " masking ratios using the Spike Activation Maps (SAM) method. The results, shown in Fig. 7, demonstrate that the models with different masking ratios concentrate on similar areas of the object at the same time step, with the red parts outlining the object. Comparison with the ANN model using the ScoreCAM method [50] reveals that both models focus on similar key information. These results suggest that the proposed RSM method preserves the regions of interest within the model, contributing to accuracy preservation." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 585, + 375, + 597 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 585, + 375, + 597 + ], + "spans": [ + { + "bbox": [ + 306, + 585, + 375, + 597 + ], + "type": "text", + "content": "5. Discussion" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "text", + "content": "In this paper, we proposed the Masked Spiking Transformer (MST) with the Random Spike Masking (RSM) method. By pruning input spikes, the proposed RSM method effectively reduces power consumption while maintaining the performance of the model within a certain range." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 666, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 666, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 666, + 545, + 713 + ], + "type": "text", + "content": "Though our experiments highlight the superiority of the MST model over state-of-the-art SNN models, our model still has limitations that need addressing. A key constraint is the relatively long time steps needed by the ANN-to-SNN" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1768" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "type": "text", + "content": "conversion method, limiting the suitability of the proposed model for real-time applications with strict timing demands." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 97, + 288, + 240 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 97, + 288, + 240 + ], + "spans": [ + { + "bbox": [ + 46, + 97, + 288, + 240 + ], + "type": "text", + "content": "Furthermore, even though the RSM method reduces the number of spikes and energy consumption, the experiment in this article merely investigates its applicability of ANN-to-SNN conversion, thus exhibiting relatively high energy consumption compared to direct-trained SNN models, which take fewer time steps. Consequently, future research could apply the RSM method to direct training methods to optimize energy consumption further and make SNNs more practical for real-world applications. Additionally, adopting different masking ratios across layers may achieve a better balance between performance and energy efficiency." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 253, + 119, + 266 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 253, + 119, + 266 + ], + "spans": [ + { + "bbox": [ + 47, + 253, + 119, + 266 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 273, + 288, + 440 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 273, + 288, + 440 + ], + "spans": [ + { + "bbox": [ + 46, + 273, + 288, + 440 + ], + "type": "text", + "content": "In this work, we propose a Masked Spiking Transformer (MST) framework that combines the energy efficiency of SNNs with the high-performance self-attention mechanism of Transformers using the ANN-to-SNN method. Additionally, we introduce a Random Spike Masking (RSM) method to prune input spikes, thus reducing power consumption. The experimental results demonstrate that the MST model outperforms current SOTA SNN models on both static and neuromorphic datasets. Furthermore, the proposed RSM method shows significant power reduction while maintaining performance in different modules of the Transformer and other SNN models. Our work opens up new possibilities for developing high-performance SNN models, paving the way for future research in this area." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 453, + 157, + 467 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 453, + 157, + 467 + ], + "spans": [ + { + "bbox": [ + 47, + 453, + 157, + 467 + ], + "type": "text", + "content": "7. Acknowledgement" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 473, + 287, + 570 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 473, + 287, + 570 + ], + "spans": [ + { + "bbox": [ + 46, + 473, + 287, + 570 + ], + "type": "text", + "content": "This work is supported by the Guangzhou-HKUST(GZ) Joint Funding Program (Grant No. 2023A03J0682), HK RGC (Grant Nos. 27206321, 17205922, 17212923), NSFC (Grant No. 62122004), National Key R&D Program of China (Grant No. SQ2022YFB3600159). This research is also partially supported by ACCESS - AI Chip Center for Emerging Smart Systems, sponsored by Innovation and Technology Fund (ITF), Hong Kong SAR." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 582, + 107, + 594 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 582, + 107, + 594 + ], + "spans": [ + { + "bbox": [ + 47, + 582, + 107, + 594 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 52, + 601, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 52, + 601, + 287, + 656 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 601, + 287, + 656 + ], + "spans": [ + { + "bbox": [ + 52, + 601, + 287, + 656 + ], + "type": "text", + "content": "[1] Yin Bi, Aaron Chadha, Alhabib Abbas, Eirina Bourtsovatze, and Yiannis Andreopoulos. Graph-based object classification for neuromorphic vision sensing. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 491-501, 2019." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 658, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 658, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 53, + 658, + 287, + 712 + ], + "type": "text", + "content": "[2] Tong Bu, Wei Fang, Jianhao Ding, PengLin Dai, Zhaofei Yu, and Tiejun Huang. Optimal ANN-SNN Conversion for High-accuracy and Ultra-low-latency Spiking Neural Networks. In International Conference on Learning Representations, 2021." + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 712 + ], + "type": "list", + "angle": 0, + "index": 22, + "blocks": [ + { + "bbox": [ + 311, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 311, + 73, + 545, + 116 + ], + "type": "text", + "content": "[3] Yongqiang Cao, Yang Chen, and Deepak Khosla. Spiking deep convolutional neural networks for energy-efficient object recognition. International Journal of Computer Vision, 113(1):54-66, 2015." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 311, + 118, + 547, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 118, + 547, + 162 + ], + "spans": [ + { + "bbox": [ + 311, + 118, + 547, + 162 + ], + "type": "text", + "content": "[4] Yongqiang Cao, Yang Chen, and Deepak Khosla. Spiking deep convolutional neural networks for energy-efficient object recognition. International Journal of Computer Vision, 113:54-66, 2015." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 311, + 163, + 547, + 207 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 163, + 547, + 207 + ], + "spans": [ + { + "bbox": [ + 311, + 163, + 547, + 207 + ], + "type": "text", + "content": "[5] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In 2009 IEEE Conference on Computer Vision and Pattern Recognition, pages 248–255. IEEE, 2009." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 311, + 209, + 547, + 251 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 209, + 547, + 251 + ], + "spans": [ + { + "bbox": [ + 311, + 209, + 547, + 251 + ], + "type": "text", + "content": "[6] Shikuang Deng, Yuhang Li, Shanghai Zhang, and Shi Gu. Temporal Efficient Training of Spiking Neural Network via Gradient Re-weighting. arXiv preprint arXiv:2202.11946, 2022." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 311, + 254, + 547, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 254, + 547, + 297 + ], + "spans": [ + { + "bbox": [ + 311, + 254, + 547, + 297 + ], + "type": "text", + "content": "[7] Jianhao Ding, Zhaofei Yu, Yonghong Tian, and Tiejun Huang. Optimal ann-snn conversion for fast and accurate inference in deep spiking neural networks. arXiv preprint arXiv:2105.11654, 2021." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 311, + 298, + 545, + 364 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 298, + 545, + 364 + ], + "spans": [ + { + "bbox": [ + 311, + 298, + 545, + 364 + ], + "type": "text", + "content": "[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, and Sylvain Gelly. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 311, + 365, + 545, + 420 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 365, + 545, + 420 + ], + "spans": [ + { + "bbox": [ + 311, + 365, + 545, + 420 + ], + "type": "text", + "content": "[9] Wei Fang, Yanqi Chen, Jianhao Ding, Ding Chen, Zhaofei Yu, Huihui Zhou, Timothée Masquelier, Yonghong Tian, and other contributors. Spikingjelly. https://github.com/fangwei123456/spikingjelly, 2020. Accessed: 2023-02-21." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 422, + 545, + 466 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 422, + 545, + 466 + ], + "spans": [ + { + "bbox": [ + 307, + 422, + 545, + 466 + ], + "type": "text", + "content": "[10] Wei Fang, Zhaofei Yu, Yanqi Chen, Tiejun Huang, Timothee Masquelier, and Yonghong Tian. Deep residual learning in spiking neural networks. Advances in Neural Information Processing Systems, 34:21056-21069, 2021." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 468, + 545, + 522 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 468, + 545, + 522 + ], + "spans": [ + { + "bbox": [ + 307, + 468, + 545, + 522 + ], + "type": "text", + "content": "[11] Wei Fang, Zhaofei Yu, Yanqi Chen, Timothée Masquelier, Tiejun Huang, and Yonghong Tian. Incorporating learnable membrane time constant to enhance learning of spiking neural networks. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2661-2671, 2021." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 523, + 545, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 523, + 545, + 600 + ], + "spans": [ + { + "bbox": [ + 307, + 523, + 545, + 600 + ], + "type": "text", + "content": "[12] Pengjie Gu, Rong Xiao, Gang Pan, and Huajin Tang. STCA: Spatio-Temporal Credit Assignment with Delayed Feedback in Deep Spiking Neural Networks. In Proceedings of the Twenty-Eighth International Joint Conference on Artificial Intelligence, pages 1366-1372, Macao, China, Aug. 2019. International Joint Conferences on Artificial Intelligence Organization." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 601, + 545, + 666 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 601, + 545, + 666 + ], + "spans": [ + { + "bbox": [ + 307, + 601, + 545, + 666 + ], + "type": "text", + "content": "[13] Bing Han, Gopalakrishnan Srinivasan, and Kaushik Roy. Rmp-snn: Residual membrane potential neuron for enabling deeper high-accuracy and low-latency spiking neural network. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13558–13567, 2020." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 669, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 669, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 669, + 545, + 712 + ], + "type": "text", + "content": "[14] Ali Hassani, Steven Walton, Nikhil Shah, Abulikemu Abuduweili, Jiachen Li, and Humphrey Shi. Escaping the big data paradigm with compact transformers. arXiv preprint arXiv:2104.05704, 2021." + } + ] + } + ], + "index": 21 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1769" + } + ] + } + ], + "index": 23 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 118, + 287, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 118, + 287, + 139 + ], + "spans": [ + { + "bbox": [ + 49, + 118, + 287, + 139 + ], + "type": "text", + "content": "[16] Geoffrey Hinton, Oriol Vinyals, and Jeff Dean. Distilling the Knowledge in a Neural Network, Mar. 2015." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 141, + 287, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 141, + 287, + 173 + ], + "spans": [ + { + "bbox": [ + 49, + 141, + 287, + 173 + ], + "type": "text", + "content": "[17] Eugene M. Izhikevich. Simple model of spiking neurons. IEEE Transactions on neural networks, 14(6):1569-1572, 2003." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 175, + 287, + 207 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 175, + 287, + 207 + ], + "spans": [ + { + "bbox": [ + 49, + 175, + 287, + 207 + ], + "type": "text", + "content": "[18] Youngeun Kim and Priyadarshini Panda. Optimizing deeper spiking neural networks for dynamic vision sensing. Neural Networks, 144:686-698, 2021." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 209, + 287, + 241 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 209, + 287, + 241 + ], + "spans": [ + { + "bbox": [ + 49, + 209, + 287, + 241 + ], + "type": "text", + "content": "[19] Youngeun Kim and Priyadarshini Panda. Optimizing deeper spiking neural networks for dynamic vision sensing. Neural Networks, 144:686-698, 2021." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 243, + 287, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 243, + 287, + 308 + ], + "spans": [ + { + "bbox": [ + 49, + 243, + 287, + 308 + ], + "type": "text", + "content": "[20] Karthik Sivarama Krishnan and Koushik Sivarama Krishnan. Benchmarking Conventional Vision Models on Neuromorphic Fall Detection and Action Recognition Dataset. In 2022 IEEE 12th Annual Computing and Communication Workshop and Conference (CCWC), pages 0518-0523. IEEE, 2022." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 310, + 287, + 331 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 310, + 287, + 331 + ], + "spans": [ + { + "bbox": [ + 49, + 310, + 287, + 331 + ], + "type": "text", + "content": "[21] Alex Krizhevsky and Geoffrey Hinton. Learning multiple layers of features from tiny images. 2009." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 333, + 287, + 365 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 333, + 287, + 365 + ], + "spans": [ + { + "bbox": [ + 49, + 333, + 287, + 365 + ], + "type": "text", + "content": "[22] Y. Lecun, L. Bottou, Y. Bengio, and P. Haffner. Gradient-based learning applied to document recognition. Proceedings of the IEEE, 86(11):2278-2324, Nov. 1998." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 367, + 287, + 399 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 367, + 287, + 399 + ], + "spans": [ + { + "bbox": [ + 49, + 367, + 287, + 399 + ], + "type": "text", + "content": "[23] William B. Levy and Robert A. Baxter. Energy-Efficient Neuronal Computation via Quantal Synaptic Failures. Journal of Neuroscience, 22(11):4746-4755, June 2002." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 401, + 287, + 434 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 401, + 287, + 434 + ], + "spans": [ + { + "bbox": [ + 49, + 401, + 287, + 434 + ], + "type": "text", + "content": "[24] Hongmin Li, Hanchao Liu, Xiangyang Ji, Guoqi Li, and Luping Shi. CIFAR10-DVS: An Event-Stream Dataset for Object Classification. Frontiers in Neuroscience, 11, 2017." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 435, + 287, + 479 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 435, + 287, + 479 + ], + "spans": [ + { + "bbox": [ + 49, + 435, + 287, + 479 + ], + "type": "text", + "content": "[25] Yuhang Li, Shikuang Deng, Xin Dong, Ruihao Gong, and Shi Gu. A free lunch from ANN: Towards efficient, accurate spiking neural networks calibration. In International Conference on Machine Learning, pages 6316-6325. PMLR, 2021." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 49, + 480, + 287, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 480, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 49, + 480, + 287, + 533 + ], + "type": "text", + "content": "[26] Yuhang Li, Yufei Guo, Shanghang Zhang, Shikuang Deng, Yongqing Hai, and Shi Gu. Differentiable spike: Rethinking gradient-descent for training spiking neural networks. Advances in Neural Information Processing Systems, 34:23426-23439, 2021." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 49, + 536, + 287, + 578 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 536, + 287, + 578 + ], + "spans": [ + { + "bbox": [ + 49, + 536, + 287, + 578 + ], + "type": "text", + "content": "[27] Yuhang Li, Youngeun Kim, Hyoungseob Park, Tamar Geller, and Priyadarshini Panda. Neuromorphic Data Augmentation for Training Spiking Neural Networks. arXiv preprint arXiv:2203.06145, 2022." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 49, + 581, + 287, + 656 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 581, + 287, + 656 + ], + "spans": [ + { + "bbox": [ + 49, + 581, + 287, + 656 + ], + "type": "text", + "content": "[28] Qianhui Liu, Dong Xing, Huajin Tang, De Ma, and Gang Pan. Event-based Action Recognition Using Motion Information and Spiking Neural Networks. In Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence, pages 1743-1749, Montreal, Canada, Aug. 2021. International Joint Conferences on Artificial Intelligence Organization." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 49, + 658, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 658, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 49, + 658, + 287, + 713 + ], + "type": "text", + "content": "[29] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10012-10022, 2021." + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "text", + "content": "[30] Wolfgang Maass. Networks of spiking neurons: The third generation of neural network models. Neural networks, 10(9):1659-1671, 1997." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 108, + 547, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 108, + 547, + 139 + ], + "spans": [ + { + "bbox": [ + 307, + 108, + 547, + 139 + ], + "type": "text", + "content": "[31] Warren S. McCulloch and Walter Pitts. A logical calculus of the ideas immanent in nervous activity. The bulletin of mathematical biophysics, 5(4):115-133, 1943." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 141, + 547, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 141, + 547, + 206 + ], + "spans": [ + { + "bbox": [ + 308, + 141, + 547, + 206 + ], + "type": "text", + "content": "[32] Qingyan Meng, Mingqing Xiao, Shen Yan, Yisen Wang, Zhouchen Lin, and Zhi-Quan Luo. Training High-Performance Low-Latency Spiking Neural Networks by Differentiation on Spike Representation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12444–12453, 2022." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 209, + 545, + 251 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 209, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 308, + 209, + 545, + 251 + ], + "type": "text", + "content": "[33] Shu Miao, Guang Chen, Xiangyu Ning, Yang Zi, Kejia Ren, Zhenshan Bing, and Alois Knoll. Neuromorphic vision datasets for pedestrian detection, action recognition, and fall detection. Frontiers in neurorobotics, 13:38, 2019." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 254, + 545, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 254, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 308, + 254, + 545, + 285 + ], + "type": "text", + "content": "[34] Paul Michel, Omer Levy, and Graham Neubig. Are sixteen heads really better than one? Advances in neural information processing systems, 32, 2019." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 288, + 545, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 288, + 545, + 342 + ], + "spans": [ + { + "bbox": [ + 308, + 288, + 545, + 342 + ], + "type": "text", + "content": "[35] Etienne Mueller, Viktor Studenyak, Daniel Auge, and Alois Knoll. Spiking Transformer Networks: A Rate Coded Approach for Processing Sequential Data. In 2021 7th International Conference on Systems and Informatics (ICSAI), pages 1-5, Nov. 2021." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 344, + 545, + 397 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 344, + 545, + 397 + ], + "spans": [ + { + "bbox": [ + 308, + 344, + 545, + 397 + ], + "type": "text", + "content": "[36] Emre O. Neftci, Hesham Mostafa, and Friedemann Zenke. Surrogate Gradient Learning in Spiking Neural Networks: Bringing the Power of Gradient-Based Optimization to Spiking Neural Networks. IEEE Signal Processing Magazine, 36(6):51-63, Nov. 2019." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 399, + 545, + 442 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 399, + 545, + 442 + ], + "spans": [ + { + "bbox": [ + 308, + 399, + 545, + 442 + ], + "type": "text", + "content": "[37] Garrick Orchard, Ajinkya Jayawant, Gregory K. Cohen, and Nitish Thakor. Converting Static Image Datasets to Spiking Neuromorphic Datasets Using Saccades. Frontiers in Neuroscience, 9, 2015." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 445, + 545, + 488 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 445, + 545, + 488 + ], + "spans": [ + { + "bbox": [ + 308, + 445, + 545, + 488 + ], + "type": "text", + "content": "[38] Wachirawit Ponghiran and Kaushik Roy. Spiking neural networks with improved inherent recurrence dynamics for sequential learning. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 8001-8008, 2022." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 491, + 545, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 491, + 545, + 521 + ], + "spans": [ + { + "bbox": [ + 308, + 491, + 545, + 521 + ], + "type": "text", + "content": "[39] Nitin Rathi and Kaushik Roy. DIET-SNN: Direct Input Encoding With Leakage and Threshold Optimization in Deep Spiking Neural Networks, Dec. 2020." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 524, + 545, + 567 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 524, + 545, + 567 + ], + "spans": [ + { + "bbox": [ + 308, + 524, + 545, + 567 + ], + "type": "text", + "content": "[40] Nitin Rathi, Gopalakrishnan Srinivasan, Priyadarshini Panda, and Kaushik Roy. Enabling deep spiking neural networks with hybrid conversion and spike timing dependent backpropagation. arXiv preprint arXiv:2005.01807, 2020." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 569, + 545, + 622 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 569, + 545, + 622 + ], + "spans": [ + { + "bbox": [ + 308, + 569, + 545, + 622 + ], + "type": "text", + "content": "[41] Bodo Rueckauer, Iulia-Alexandra Lungu, Yuhuang Hu, Michael Pfeiffer, and Shih-Chii Liu. Conversion of continuous-valued deep networks to efficient event-driven networks for image classification. Frontiers in neuroscience, 11:682, 2017." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 624, + 545, + 656 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 624, + 545, + 656 + ], + "spans": [ + { + "bbox": [ + 308, + 624, + 545, + 656 + ], + "type": "text", + "content": "[42] Karen Simonyan and Andrew Zisserman. Very Deep Convolutional Networks for Large-Scale Image Recognition, Apr. 2015." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 658, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 658, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 658, + 545, + 713 + ], + "type": "text", + "content": "[43] Amos Sironi, Manuele Brambilla, Nicolas Bourdis, Xavier Lagorce, and Ryad Benosman. HATS: Histograms of Averaged Time Surfaces for Robust Event-Based Object Classification. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1731-1740, 2018." + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 749, + 315, + 757 + ], + "type": "text", + "content": "1770" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[44] Nitish Srivastava, Geoffrey Hinton, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. Dropout: A simple way to prevent neural networks from overfitting. The journal of machine learning research, 15(1):1929-1958, 2014." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 118, + 286, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 118, + 286, + 149 + ], + "spans": [ + { + "bbox": [ + 49, + 118, + 286, + 149 + ], + "type": "text", + "content": "[45] Kenneth M. Stewart and Emre O. Neftci. Meta-learning spiking neural networks with surrogate gradient descent. Neuro-morphic Computing and Engineering, 2(4):044002, 2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 151, + 286, + 193 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 151, + 286, + 193 + ], + "spans": [ + { + "bbox": [ + 49, + 151, + 286, + 193 + ], + "type": "text", + "content": "[46] Christoph Stöckl and Wolfgang Maass. Optimized spiking neurons can classify images with high accuracy through temporal coding with two spikes. Nature Machine Intelligence, 3(3):230-238, 2021." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 195, + 286, + 238 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 195, + 286, + 238 + ], + "spans": [ + { + "bbox": [ + 49, + 195, + 286, + 238 + ], + "type": "text", + "content": "[47] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, " + }, + { + "bbox": [ + 49, + 195, + 286, + 238 + ], + "type": "inline_equation", + "content": "\\backslash" + }, + { + "bbox": [ + 49, + 195, + 286, + 238 + ], + "type": "text", + "content": " Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 239, + 286, + 303 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 239, + 286, + 303 + ], + "spans": [ + { + "bbox": [ + 49, + 239, + 286, + 303 + ], + "type": "text", + "content": "[48] Alberto Viale, Alberto Marchisio, Maurizio Martina, Guido Masera, and Muhammad Shafique. Carsnn: An efficient spiking neural network for event-based autonomous cars on the loihi neuromorphic research processor. In 2021 International Joint Conference on Neural Networks (IJCNN), pages 1-10. IEEE, 2021." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 305, + 286, + 348 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 305, + 286, + 348 + ], + "spans": [ + { + "bbox": [ + 49, + 305, + 286, + 348 + ], + "type": "text", + "content": "[49] Elena Voita, David Talbot, Fedor Moiseev, Rico Sennrich, and Ivan Titov. Analyzing multi-head self-attention: Specialized heads do the heavy lifting, the rest can be pruned. arXiv preprint arXiv:1905.09418, 2019." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 350, + 286, + 415 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 350, + 286, + 415 + ], + "spans": [ + { + "bbox": [ + 49, + 350, + 286, + 415 + ], + "type": "text", + "content": "[50] Haofan Wang, Zifan Wang, Mengnan Du, Fan Yang, Zijian Zhang, Sirui Ding, Piotr Mardziel, and Xia Hu. Score-CAM: Score-Weighted Visual Explanations for Convolutional Neural Networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops, pages 24–25, 2020." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 416, + 286, + 458 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 416, + 286, + 458 + ], + "spans": [ + { + "bbox": [ + 49, + 416, + 286, + 458 + ], + "type": "text", + "content": "[51] Zheyu Yang, Yujie Wu, Guanrui Wang, Yukuan Yang, Guoqi Li, Lei Deng, Jun Zhu, and Luping Shi. DashNet: A hybrid artificial and spiking neural network for high-speed object tracking. arXiv preprint arXiv:1909.12942, 2019." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 460, + 286, + 514 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 460, + 286, + 514 + ], + "spans": [ + { + "bbox": [ + 49, + 460, + 286, + 514 + ], + "type": "text", + "content": "[52] Man Yao, Huanhuan Gao, Guangshe Zhao, Dingheng Wang, Yihan Lin, Zhaoxu Yang, and Guoqi Li. Temporal-wise attention spiking neural networks for event streams classification. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 10221-10230, 2021." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 515, + 286, + 557 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 515, + 286, + 557 + ], + "spans": [ + { + "bbox": [ + 49, + 515, + 286, + 557 + ], + "type": "text", + "content": "[53] Zhuliang Yao, Yue Cao, Yutong Lin, Ze Liu, Zheng Zhang, and Han Hu. Leveraging batch normalization for vision transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 413-422, 2021." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 559, + 286, + 613 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 559, + 286, + 613 + ], + "spans": [ + { + "bbox": [ + 49, + 559, + 286, + 613 + ], + "type": "text", + "content": "[54] Jiqing Zhang, Bo Dong, Haiwei Zhang, Jianchuan Ding, Felix Heide, Baocai Yin, and Xin Yang. Spiking Transformers for Event-Based Single Object Tracking. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8801-8810, 2022." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 49, + 614, + 286, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 614, + 286, + 668 + ], + "spans": [ + { + "bbox": [ + 49, + 614, + 286, + 668 + ], + "type": "text", + "content": "[55] Jiyuan Zhang, Lulu Tang, Zhaofei Yu, Jiwen Lu, and Tiejun Huang. Spike Transformer: Monocular Depth Estimation for Spiking Camera. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part VII, pages 34-52. Springer, 2022." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 49, + 670, + 286, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 670, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 49, + 670, + 286, + 712 + ], + "type": "text", + "content": "[56] Hanle Zheng, Yujie Wu, Lei Deng, Yifan Hu, and Guoqi Li. Going deeper with directly-trained larger spiking neural networks. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 11062-11070, 2021." + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 149 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "text", + "content": "[57] Zhaokun Zhou, Yuesheng Zhu, Chao He, Yaowei Wang, Shuicheng Yan, Yonghong Tian, and Li Yuan. Spikformer: When Spiking Neural Network Meets Transformer. arXiv preprint arXiv:2209.15425, 2022." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 118, + 545, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 545, + 149 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 545, + 149 + ], + "type": "text", + "content": "[58] Michael Zhu and Suyog Gupta. To prune, or not to prune: Exploring the efficacy of pruning for model compression, Nov. 2017." + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 749, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 749, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 749, + 314, + 757 + ], + "type": "text", + "content": "1771" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Mastering Spatial Graph Prediction of Road Networks/e2e1da73-cf2c-48bb-9b35-8cf5cb0f98fc_content_list.json b/2023/Mastering Spatial Graph Prediction of Road Networks/e2e1da73-cf2c-48bb-9b35-8cf5cb0f98fc_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..8f3fb2a6d08213ceb175ee8cd3c473cbd5c54d7a --- /dev/null +++ b/2023/Mastering Spatial Graph Prediction of Road Networks/e2e1da73-cf2c-48bb-9b35-8cf5cb0f98fc_content_list.json @@ -0,0 +1,1401 @@ +[ + { + "type": "text", + "text": "Mastering Spatial Graph Prediction of Road Networks", + "text_level": 1, + "bbox": [ + 207, + 130, + 763, + 152 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/39e1605452bce5ce8cf84949b7a25e8c56a8e5a386b9bed9b83b78f260088d1b.jpg", + "image_caption": [ + "Figure 1. Our agent interacts with the currently generated spatial graph by proposing new edges to be added. A tree-based search produces a sequence of actions that maximizes a reward function based on complex geometrics priors." + ], + "image_footnote": [], + "bbox": [ + 135, + 179, + 834, + 417 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 470, + 313, + 488 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Accurately predicting road networks from satellite images requires a global understanding of the network topology. We propose to capture such high-level information by introducing a graph-based framework that given a partially generated graph, sequentially adds new edges. To deal with misalignment between the model predictions and the intended purpose, and to optimize over complex, non-continuous metrics of interest, we adopt a reinforcement learning (RL) approach that nominates modifications that maximize a cumulative reward. As opposed to standard supervised techniques that tend to be more restricted to commonly used surrogate losses, our framework yields more power and flexibility to encode problem-dependent knowledge. Empirical results on several benchmark datasets demonstrate enhanced performance and increased high-level reasoning about the graph topology when using a tree-based search. We further demonstrate the superiority of our approach in handling examples with substantial occlusion and additionally provide evidence that our predictions better match the statistical properties of the ground dataset.", + "bbox": [ + 75, + 503, + 473, + 806 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 821, + 209, + 835 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Road layout modelling from satellite images constitutes an important task of remote sensing, with applications in", + "bbox": [ + 75, + 845, + 470, + 878 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "everyday life, such as traffic flow prediction and navigation. The vast amounts of data available from the commercialization of geospatial data, in addition to the need for accurately establishing the connectivity of roads in remote areas, have led to an increased interest in the precise representation of existing road networks. By nature, these applications require structured data types that provide efficient representations to encode geometry, in this case, graphs, a de facto choice in domains such as computer graphics, virtual reality, gaming, and the film industry. These structured-graph representations are also commonly used to label recent road network datasets [60] and map repositories [40]. When dealing with complex predicted structures, however, how well the model optimizes a surrogate objective is not always the best indication of how well the model's predictions are aligned with the required task risk, i.e. the targeted final utilization.", + "bbox": [ + 500, + 472, + 892, + 729 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Problems of this nature have been recently extensively studied in the regime of natural language processing, where the misalignment between training objectives for tasks such as machine translation and summarization has garnered considerable attention among the academic community, who have devoted significant efforts to its analysis and elucidation. A popular emerging technique is to first learn to imitate some example outputs and then fix any misalignment issues by using reinforcement learning to adjust the predictions based on a reward function. The reward usually comes in the form of external human evaluation [41, 4].", + "bbox": [ + 496, + 734, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 47 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "$^{1}$ Correspondence sotirios.anagnostidis@inf.ethz.ch.", + "bbox": [ + 94, + 886, + 370, + 901 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "5408", + "bbox": [ + 482, + 946, + 516, + 957 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/289d74b5d8a6c6159644d8abbf0c30870bb8988556e3286346230df1ae30e3c4.jpg", + "image_caption": [ + "Figure 2. Typical road network features (SpaceNet dataset). From left to right: (a) the distribution of angles between road segments leading to the same intersection is biased towards 0 and 90 degrees, i.e. parallel or perpendicular roads. The same also holds (b) for angles between random road pieces within a ground distance of 400 meters. (c) Most road vertices belong to a single road piece, with a degree of 2. (d) The average number of intersections for areas of $400 \\times 400$ meters by ground distance." + ], + "image_footnote": [], + "bbox": [ + 101, + 90, + 285, + 215 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/fac45254ed5c48ba27e03a969eeb3008f80a5492ff823b3b086b98f006c1060e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 295, + 90, + 480, + 215 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/aa09bbcd1294069573c2a851e307fe6f114f5107efd8469ab08fd1ca396d7aa4.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 491, + 90, + 671, + 215 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/3ea6de973e7faf2eb4f3627c7a3e60158c58eadb5ce6bd0b7f6681e886e91b41.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 681, + 90, + 864, + 215 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this work we manifest how RL fine-tuning can greatly benefit and boost performance when producing intricate geometric predictions. For the task of road layout detection, existing methods, in contrast, mostly rely on pixel-based segmentation models that are trained on masks produced by rasterizing ground truth graphs. Performing pixel-wise segmentation, though, ignores structural features and geometric constraints inherent to the problem. As a result, minimum differences in the pixel-level output domain can have significant consequences in the proposed graph, in terms of connectivity and path distances, as manifested by the often fragmented outputs obtained after running inference on these models. In order to address these significant drawbacks, we propose a new paradigm where we (i) directly generate outputs as spatial graphs and (ii) formalize the problem as a game where we sequentially construct the output by adding edges between key points. These key points can in principle come from any off-the-shelf detector that identifies road pieces with sufficient accuracy. Our generation process avoids having to resort to cumbersome post-processing steps [8, 32] or optimize some surrogate objectives [30, 34] whose relation to the desired qualities of the final prediction can be disputed. Concurrently, the sequential decision-making strategy we propose enables us to focus interactively on different parts of the image, introducing the notion of a current state and producing reward estimates for a succession of actions. In essence, our method can be considered as a generalization of previous refinement techniques [8, 26] with three major advantages: (i) removal of the requirement for greedy decoding, (ii) ability to attend globally to the current prediction and selectively target parts of the image, and (iii) capacity to train based on demanding task-specific metrics.", + "bbox": [ + 76, + 287, + 472, + 786 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "More precisely, our contributions are the following:", + "bbox": [ + 96, + 787, + 439, + 803 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose a novel generic strategy for tuning autoregressive models that removes the requirement of decoding according to a pre-defined order and refines initial sampling probabilities via a tree search.", + "- We create a synthetic benchmark dataset of pixel-level" + ], + "bbox": [ + 94, + 816, + 470, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "accurate labels of overhead satellite images for the task of road network extraction. This gives us the ability to simulate complex scenarios with occluded regions, allowing us to demonstrate improved robustness.", + "bbox": [ + 529, + 287, + 890, + 349 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "- We confirm the wide applicability of our approach by improving the performance of existing methods on the popular SpaceNet and DeepGlobe datasets.", + "bbox": [ + 517, + 356, + 893, + 402 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related work", + "text_level": 1, + "bbox": [ + 500, + 419, + 637, + 435 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Initial attempts to extract road networks mainly revolved around handcrafted features and stochastic geometric models of roads [6]. Road layouts have specific characteristics regarding radiometry and topology e.g. particular junction distribution, certain general orientation, and curvature (see Fig. 2), that enable their detection even in cases with significant occlusion and uncertainty [19]. Modern approaches mostly formulate the road extraction task as a segmentation prediction task [27, 31, 3] by applying models such as Hourglass [37] or LinkNet [10]. This interpretation has significant drawbacks when evaluated against structural losses because of discontinuities in the predicted masks. Such shortcomings have been addressed by applying some additional post-processing steps, such as high-order conditional random fields [38, 65] or by training additional models that refine these initial predictions [29, 8]. Other common techniques include the optimization of an ensemble of losses. [13] rely on a directional loss and use non-maximal suppression as a thinning layer, while [8] calculate orientations of road segments. Although such auxiliary losses somewhat improve the output consistency, the fundamental issue of producing predictions in the pixel space persists. It remains impossible to overcome naturally occurring road structures, e.g. crossings of roads in different elevations, see Fig. 3.", + "bbox": [ + 496, + 446, + 890, + 808 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Previous failure cases have led to more intuitive conceptualizations of the task. Roadtracer [7], iteratively builds a road network, similar to a depth-first search approach, while [13] learn a generative model for road layouts and then apply it as a prior on top of a segmentation prediction mask. Proposed graph-based approaches encode the road", + "bbox": [ + 496, + 810, + 893, + 901 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "5409", + "bbox": [ + 482, + 946, + 514, + 957 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/ae7401aa94dbf125c2a87995e1e91ac77a5055cc773f910726b66a16bdfa70c5.jpg", + "image_caption": [ + "Figure 3. (Left) Typical segmentation-based methods generate an output graph by thresholding a segmentation mask, which can however often lead to fragmented outputs. Predicting segmentation masks also makes it impossible (right) to capture complex road interactions, such as overlapping roads at different elevations." + ], + "image_footnote": [], + "bbox": [ + 140, + 89, + 831, + 224 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "network directly as a graph, but either operate based on a constrained step-size [56] to generate new vertices or operate on a single step [18, 5], involving use-defined thresholding to post-process the final predictions. Most similar to our work, [26] predict locations of key points and define a specific order traversing them, as also done in [69]. Such autoregressive models have been recently successfully applied with the use of transformers [61] in a range of applications [36, 42, 43, 69] to model constraints between elements, where their supervised training explicitly requires tokens to be processed in a specific order. This specific order combined with the fact that only a surrogate training objective is used, introduces limitations, discussed further in the next section. In order to eliminate this order requirement and to optimize based on the desired metric, while attending globally to the currently generated graph, we propose to use RL as a suitable technique to tune these models.", + "bbox": [ + 75, + 286, + 472, + 542 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "RL has found success in the past in computer vision applications, we refer the interested reader to [24] for a comprehensive review. These approaches mainly use RL as an auxiliary unit with the goal of improving efficiency [68] or robustness [45]. We differ from these as we use RL to tune pre-trained models with the goal of aligning with a specified task-specific reward. Such tuning was concurrently shown to significantly boost performance for tasks such as object detection, among others [54].", + "bbox": [ + 75, + 542, + 472, + 679 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Methodology", + "text_level": 1, + "bbox": [ + 76, + 683, + 212, + 700 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We parametrize a road network as a graph $\\mathcal{G} = \\{\\mathcal{V},\\mathcal{E}\\}$ with each vertex $v_{i} = [x_{i},y_{i}]^{\\top}\\in \\mathcal{V}$ representing a key point on the road surface. The set of edges $(v_{i},v_{j})\\in \\mathcal{E}$ corresponds to road segments connecting these key points. We can then generate a probability distribution over roads by following a two-step process: i) generation of a set of vertices and ii) generation of a set of edges connecting them. Formally, for an image $\\mathcal{I}$ , a road network $\\mathcal{R}$ is derived as:", + "bbox": [ + 75, + 708, + 468, + 829 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {R} = \\underset {\\mathcal {V}, \\mathcal {E}} {\\arg \\max } P (\\mathcal {V}, \\mathcal {E} \\mid \\mathcal {I}) = P (\\mathcal {E} \\mid \\mathcal {V}, \\mathcal {I}) P (\\mathcal {V} \\mid \\mathcal {I}). \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 94, + 837, + 468, + 863 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The graph nodes typically correspond to local information in an image, and we therefore resort to a CNN-based model", + "bbox": [ + 76, + 869, + 470, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "to extract key points, providing the set $\\mathcal{V}'$ , that sufficiently captures the information in the ground truth graph $\\mathcal{G}$ . The construction of edges, however, requires higher-level reasoning that can cope with parallel roads, junctions, occlusions, or poor image resolution, among other difficulties.", + "bbox": [ + 496, + 286, + 890, + 361 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Considering probabilistic models over sequences and using the chain rule, we can factorize the joint distribution as the product of a series of conditional distributions", + "bbox": [ + 496, + 362, + 890, + 407 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nP (\\mathcal {E} \\mid \\mathcal {V}, \\mathcal {I}; \\sigma) = \\prod_ {n = 1} ^ {N _ {\\mathcal {E}}} P \\left(e _ {\\sigma (n)} \\mid e _ {< \\sigma (n)}, \\mathcal {V}, \\mathcal {I}\\right), \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 542, + 421, + 890, + 463 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $e_{<\\sigma(n)}$ represents $e_{\\sigma(1)}, e_{\\sigma(2)}, \\ldots, e_{\\sigma(n-1)}$ and $\\sigma \\in S_{N_{\\mathcal{E}}}$ denotes the set of all permutations of the integers $1, 2, \\ldots, N_{\\mathcal{E}}$ , with $N_{\\mathcal{E}}$ the number of edges. For our work we consider the setting where these sequences are upper bounded in length, i.e. $N_{\\mathcal{E}} \\leq N_{\\max}$ , since we are dealing with satellite images of fixed size. Autoregressive models (ARMs) have been used to solve similar tasks in the past by defining a fixed order of decoding [39, 59, 36, 42]. In our case, this would correspond to sorting all key points by their coordinates $x$ and $y$ and generating edges for each of them sequentially. We call this the autoregressive order. There are, however, two major drawbacks.", + "bbox": [ + 496, + 477, + 892, + 657 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "First, the evaluation metrics used for this task define a buffer region in which nodes in the ground truth and the predicted graph are considered to be a match. Therefore, a newly generated edge can be only partially correct when only partially overlapping with the ground truth graph. This non-smooth feedback comes in clear contrast to the supervised training scheme of ARMs, minimization of the negative log-likelihood, that assumes perfect information regarding the key points' locations, i.e. that the sets $\\mathcal{V}$ and $\\mathcal{V}'$ are the same. In practice, this condition is rarely met as the exact spatial graph can be represented in arbitrarily many ways by subdividing long edges into smaller ones or due to small perturbation to key points' locations. It is thus imperative that our model can estimate the expected improvement of adding selected edges, which implicitly can also signal when to appropriately end the generation process.", + "bbox": [ + 496, + 659, + 893, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "5410", + "bbox": [ + 482, + 946, + 514, + 957 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Second, the requirement to decode according to the autoregressive order introduces a bias and limits the expressiveness of the model [58]. As a result, it can lead to failures in cases with blurry inputs or occlusions [26]. We employ RL to overcome these deficiencies and align the model with the required objective. In more detail, we tune an autoregressive model, described in Section 3.1, with the ability to search into sequences of actions in the future, as described in Section 3.2. Our novel generic strategy improves the autoregressive model without requiring significantly more computational resources.", + "bbox": [ + 75, + 90, + 472, + 257 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.1. Autoregressive model", + "text_level": 1, + "bbox": [ + 76, + 261, + 277, + 275 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We start by introducing a base autoregressive model, illustrated in Fig. 4. Given an image and a set of key points, i.e a set of vertices $\\mathcal{V}'$ , our model produces a graph by sequentially predicting a list of indices corresponding to the graph's flattened, unweighted edge-list. Each forward pass produces probabilities over the set of key points, which leads to a new index after sampling. A successive pair of indices defines an edge as its two endpoints. A special end-of-sequence token is reserved to designate the end of the generation process.", + "bbox": [ + 75, + 284, + 468, + 434 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Following [63, 53], we begin by extracting visual features per key point, by interpolating intermediate layers of a ResNet backbone to the key points' locations, which are further augmented by position encodings of their locations. We then further process these features using two Transformer modules. The first transformer (Transformer I in Fig. 4) encodes the raw features of the key points as embeddings. The second transformer (Transformer II in Fig. 4) takes as input the currently generated edge list sequence, corresponding to the currently partially generated graph. Edges are directly mapped to the embeddings of their comprising key points, supplemented by position and type embeddings, to differentiate between them, as shown in Fig. 5 (a). An additional global image embedding also extracted by the ResNet is used to initialize the sequence. The Transformer II module produces a single hidden state, which is linked with the $N_{\\mathcal{V}'} + 1$ (corresponding to the provided key points, supplemented by the special end of the generation token) key points' embeddings by a pointer network [62], via a dot-product. This allows the generation of a probability distribution of variable length depending on the current set $\\mathcal{V}'$ , instead of using a fixed action space.", + "bbox": [ + 75, + 436, + 472, + 768 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Augmented search", + "text_level": 1, + "bbox": [ + 76, + 771, + 256, + 786 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In order to address the problems of greedy decoding (analyzed in Section 3), we frame our road extraction task as a classical Markov-decision process (MDP). The generation of a graph for every image defines an environment, where the length of the currently generated edge list determines the current step. Let $\\boldsymbol{o}_t$ , $\\alpha_t$ and $r_t$ correspond to the observation, the action, i.e. the selected key point index,", + "bbox": [ + 75, + 794, + 468, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "and the observed reward respectively, at time step $t$ . The aim is to search for a policy that maximizes the expected cumulative reward over a horizon $T$ , i.e., $\\max_{\\pi} J(\\pi) := \\mathbb{E}_{\\pi} \\left[ \\sum_{t=0}^{T-1} \\gamma^t r_t \\right]$ where $\\gamma \\in (0,1]$ indicates the discount factor and the expectation is with respect to the randomness in the policy and the transition dynamics. We set the discount factor to 1 due to the bounded time horizon.", + "bbox": [ + 496, + 90, + 890, + 198 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Instead of training a reward model [41], we employ established graph-theoretic metrics that also allow the definition of intermediate rewards, accelerating initial training. More formally, each action leads to the selection of a new key point, with new edges being added once every two actions. The addition of a new edge leads to a revision of the predicted graph and triggers an intermediate reward", + "bbox": [ + 496, + 198, + 890, + 305 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nr _ {t} = \\operatorname {s c} \\left(\\mathcal {G} _ {\\mathrm {g t}}, \\mathcal {G} _ {\\text {p r e d} _ {t}}\\right) - \\operatorname {s c} \\left(\\mathcal {G} _ {\\mathrm {g t}}, \\mathcal {G} _ {\\text {p r e d} _ {t - 1}}\\right), \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 566, + 314, + 890, + 332 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\operatorname{sc}(\\mathcal{G}_{\\mathrm{gt}}, \\mathcal{G}_{\\mathrm{pred}_t})$ is a similarity score between the ground truth graph $\\mathcal{G}_{\\mathrm{gt}}$ and the current estimate $\\mathcal{G}_{\\mathrm{pred}_t}$ . Discussion of the specific similarity scores used in practice is postponed for Section 3.3.", + "bbox": [ + 496, + 339, + 890, + 400 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "A proper spatial graph generation entails (i) correct topology and (ii) accurate location prediction of individual roads. For the latter, intermediate vertices of degree 2 are essential. We call a road segment (RS), an ordered collection of edges, between vertices of degree $d(\\cdot)$ two (or a collection of edges forming a circle):", + "bbox": [ + 496, + 400, + 890, + 491 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathrm {R S} = \\left\\{\\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {1}}, \\boldsymbol {v} _ {\\mathrm {r s} _ {2}}\\right), \\dots , \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {k - 1}}, \\boldsymbol {v} _ {\\mathrm {r s} _ {k}}\\right) \\right\\} \\\\ \\mathrm {s . t} \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {i}}, \\boldsymbol {v} _ {\\mathrm {r s} _ {i + 1}}\\right) \\in \\mathcal {E} \\text {f o r} i = 1, \\dots , k - 1 \\\\ d \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {i}}\\right) = 2, \\text {f o r} i = 2, \\dots k - 1, \\\\ \\left(d \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {1}}\\right) \\neq 2 \\text {a n d} d \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {k}}\\right) \\neq 2 \\text {o r} \\boldsymbol {v} _ {\\mathrm {r s} _ {1}} = \\boldsymbol {v} _ {\\mathrm {r s} _ {k}}\\right). \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 544, + 500, + 844, + 574 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "During the progression of an episode (i.e. the sequential generation of a graph), the topological nature of the similarity scores in Eq. 3 implies that the effect of each new edge to the reward will be reflected mostly once its whole corresponding road segment has been generated. To resolve the ambiguity in the credit assignment and allow our agent to look ahead into sequences of actions, we rely on Monte Carlo Tree Search (MCTS) to simulate entire sequences of actions. We use a state-of-the-art search-based agent, MuZero [48], that constructs a learnable model of the environment dynamics, simulating transitions in this latent representation and leading to significant computational benefits. At every step, the enhanced model with its new components produces value [50] and reward estimates, which define an exploration strategy. Simulations into future sequences of actions are performed based on this strategy, helping the model to make decisions based on future outcomes, not yet experienced. Compared to a simpler PPO objective [49, 41], that in our experience did not lead to significant improvements, MCTS generates a series of simulations traversing the tree from a root node, generating more", + "bbox": [ + 496, + 583, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "5411", + "bbox": [ + 482, + 946, + 513, + 957 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/5d674a1311acd3c4b95c744697c9304c3b0c023a027839930ef5e2ce5410de8a.jpg", + "image_caption": [ + "Figure 4. The autoregressive model with its three main components. (1) A backbone image model (ResNet) that extracts features for each key point at different scales, along with a global image embedding. (2) A key point model embeds visual and location features of distinct key points. (3) An edge embedding model relates the current edge sequence with the respective key points. Each edge token (signalled with the tokens 'index-i') corresponds to an index specifying the respective key point. A pair of such tokens designates an edge as its two endpoints. At the end of (3) we obtain a new distribution over key points that leads to an incremental update to the graph, after sampling." + ], + "image_footnote": [], + "bbox": [ + 212, + 88, + 759, + 297 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "stable value and reward estimates. MuZero requires three distinct parts (see also Fig. 5):", + "bbox": [ + 75, + 390, + 470, + 421 + ], + "page_idx": 4 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1. A representation function $f$ creates a latent vector of the current state $\\pmb{h}_t = f_\\theta(\\pmb{o}_t)$ , in our case the autoregressive model, shown in Fig. 4. Our current latent representation $\\pmb{h}_t$ contains the graph's hidden state along with the key points' embeddings used to map actions to latent vectors. As key points remain the same throughout the episode, image-based features (Components (1) and (2) in Fig. 4) are only computed once.", + "2. A dynamics network $g$ , we use a simple LSTM [20], as commonly done, that predicts the effect of a new action by predicting the next hidden state and the expected reward: $(\\hat{h}_t, \\hat{r}_t) = g_\\theta(\\hat{h}_{t-1}, \\alpha_t)$ . We can replace $\\tilde{h}_{t-1}$ with the latent representation $h_{t-1}$ , or its previous computed approximation $\\hat{h}_{t-1}$ for tree search of depth larger than 1.", + "3. A prediction network $\\psi$ , that estimates the policy and the value for the current state $(\\pmb{p}_{t+1}, v_t) = \\psi_\\theta(\\tilde{\\pmb{h}}_t)$ . We compute the policy via a pointer network as described in Section 3.1. Value estimates are produced by a simple multi-layer perceptron." + ], + "bbox": [ + 88, + 434, + 472, + 751 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The dynamics network guides the search and evaluates the expected reward of actions. For every newly generated edge, we also explicitly inform the network regarding the creation of new intersections and the expected relative change in the overall road surface generated via embeddings (see Fig. 5). By using the dynamics network, we bypass the expensive call to the decoder module during the search, and can instead approximate small modifications in the latent representation directly. For our experiments, the dynamics", + "bbox": [ + 75, + 763, + 470, + 902 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/bacb4f43b159a22feb9ec2adcd9e94fabbebc9be883d27232656d909cdeecc40.jpg", + "image_caption": [ + "Figure 5. The autoregressive model generates a hidden state corresponding to the graph embedding. (a) When doing so, the edge decoder directly attends to the input key points' embeddings, augmented by position and type embeddings. (b) The prediction network uses the hidden state to produce value and policy predictions. A pointer network allows an intuitive scale of the action space by the number of key points. (c) The dynamics network simulates trajectories by estimating new hidden states and rewards. For newly generated edges, it takes as input the embeddings of the new key points, but also the degree of the two vertices involved and the length of the newly proposed generated edge." + ], + "image_footnote": [], + "bbox": [ + 506, + 388, + 888, + 536 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "network requires up to 90 times less floating-point operations to simulate trajectories, compared to using the edge embeddings' decoder. Effectively, our method does not involve significantly more computation budget compared to the base autoregressive model. More details regarding the MuZero training and exploration are provided in Section 4 and in the appendix.", + "bbox": [ + 496, + 709, + 893, + 816 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.3. Evaluation metrics", + "text_level": 1, + "bbox": [ + 500, + 830, + 681, + 845 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We adopt the same evaluation metrics both as a comparison between different methods and to determine the reward for our agent, through Eq. 3. We use the relaxed versions of", + "bbox": [ + 498, + 854, + 893, + 902 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "5412", + "bbox": [ + 482, + 946, + 514, + 957 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "precision, recall, and intersection over union for pixel-level predictions Correctness/Completeness/Quality (CCQ) [66, 64]. As graph-theoretic metrics we use APLS [60] and additionally include new metrics introduced in [14] that compare Paths, Junctions and Sub-graphs of the graphs in question, producing respectively precision, recall and $f_{1}$ scores. More details can be found in the appendix.", + "bbox": [ + 75, + 90, + 472, + 196 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 214, + 209, + 232 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Implementation details. We resize images to $300 \\times 300$ pixels, standardizing according to the training set statistics. For exploration, we initialize workers using Ray [33] that execute episodes in the environment. For training, we unroll the dynamics function for $t_d = 5$ steps and use priority weights for the episode according to the differences between predicted and target values. Our algorithm can be considered as an approximate on-policy TD( $\\lambda$ ) [55] due to the relatively small replay buffer. We reanalyse older games [48] to provide fresher target estimates. Unvisited graph nodes are selected based on an upper confidence score, balancing exploration with exploitation, similar to [51]. We add exploration noise as Dirichlet noise and select actions based on a temperature-controlled sampling procedure, whose temperature is reduced during training.", + "bbox": [ + 75, + 241, + 468, + 467 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Given the limited high-quality available ground truth labels [52] and to accelerate training, we employ modifications introduced in EfficientZero [71]. We investigate adding supervision to the environment model and better initialize Q-value predictions similar to the implementation of Elf OpenGo [57]. We further scale values and rewards using an invertible transform inspired by [44]. Here, we predict support, as fully connected networks are biased towards learning low-frequency representations [21]. Selecting new actions involves generating simulations that can be done expeditiously given the small dimension of the latent space and the modest size of the dynamics network. Finally, to generate key points, we skeletonize segmentation masks provided by any baseline segmentation model, by thresholding the respective segmentation masks produced and applying RDP-simplification [17, 46]. Selecting an appropriate threshold and subdividing larger edges guarantees that the generated set $\\mathcal{V}'$ adequately captures most of the ground truth road network, leaving the complexity of the problem for our model to handle. We will use the term ARM to denote the autoregressive model and Ours for the RL-tuned model.", + "bbox": [ + 75, + 469, + 470, + 801 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Synthetic dataset", + "text_level": 1, + "bbox": [ + 76, + 815, + 243, + 830 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Initially, a simplified setting is chosen wherein the complete governance of both the nature and intensity of the difficulty inherent in the road-extraction task can be regulated. We generate a dataset of overhead satellite images of a syn", + "bbox": [ + 75, + 839, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/d4914a2d2c86ee8ef4099f953c98ae4debab9d3d3bae666611cee750869bd331.jpg", + "image_caption": [ + "Figure 6. (Left) Examples of fragmented outputs from the LinkNet model under cases of significant occlusion and how our approach performs in these demanding circumstances. (Right) The performance gap between our method and the same baseline is wide, based on topological spatial graph metrics, for a wide range of difficulties in the images. More details and examples are given in the supplementary material." + ], + "image_footnote": [], + "bbox": [ + 501, + 89, + 890, + 277 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "thetic town using CityEngine1. We randomly specify vegetation of varying height and width along the side walks of the generated streets, leading inadvertently to occlusions of varying difficulty. The simulated environment allows specifying pixel-perfect masks regarding both roads and trees occluding the road surface based on the provided camera parameters [23]. We defer more details regarding the generation process and dataset examples to the supplementary material.", + "bbox": [ + 496, + 393, + 892, + 527 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We compare our method by training on our dataset a LinkNet model [10], a popular segmentation model that has been widely used in the remote sensing community [25]. Even in this synthetic and thus less diverse scenario, the deficiency of segmentation models to rely mostly on local information, with no explicit ability for longer-range interactions, is evident. Fig. 6 illustrates examples of such oversegmented predictions and how our approach can improve on them. We also define a 'difficulty' attribute per synthetic satellite image, quantifying the occlusions as a percentage of the ground truth road mask covered. We observe a considerable absolute improvement in topological metric scores when training our model on this synthetic dataset, compared to the baseline, for varying image difficulty.", + "bbox": [ + 496, + 530, + 890, + 741 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Real datasets", + "text_level": 1, + "bbox": [ + 500, + 751, + 638, + 766 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We assess our approach on the SpaceNet and DeepGlobe datasets. A single image is provided to our method, with a spatial graph being generated as the output. We use the same train-test splits as in [8] to promote reproducibility, while results are reported for the final combined graph on the original image scale. No pre-training on the synthetic", + "bbox": [ + 496, + 773, + 890, + 866 + ], + "page_idx": 5 + }, + { + "type": "page_footnote", + "text": "1https://www.esri.com/en-us/arcgis/products/arcgis-cityengine/overview", + "bbox": [ + 500, + 875, + 795, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "5413", + "bbox": [ + 482, + 946, + 514, + 957 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/4d972e860e96a85d053dca875319e3a60b83a5cec687b44911a4cbdd42a09090.jpg", + "table_caption": [], + "table_footnote": [ + "* We do not fine-tune our model on the DeepGlobe dataset but instead refine predictions standardizing according to train dataset statistics.", + "** The authors provided predictions corresponding only to a center crop of the original SpaceNet dataset images. Also, note that the test set is different from the one reported on the rest of the methods, see also the appendix. Blue: best score, Green: second best score, Gray: results reported in different test set" + ], + "table_body": "
MethodCCQTLTSAPLS ↑Path-BasedJunction-BasedSub-graph-Based f1 ↑
corr. ↑comp. ↑qual. ↑corr. ↑2l+2s ↓pre. ↑rec. ↑f1 ↑pre. ↑rec. ↑f1 ↑
SpaceNetDeepRoadMapper [29]0.69430.68380.53860.41100.10120.51430.59580.64000.61710.62930.74430.68200.6783
Segmentation [28, 22]0.74930.70940.59690.41430.08280.54540.69090.68630.68850.71860.77100.74380.7117
LinkNet [10]0.81000.74490.64090.48940.07430.57430.67190.64600.65860.69850.78090.73740.7576
Orientation [8]0.80700.80010.68620.55940.08840.63150.71750.72800.72270.75520.75910.75710.7802
Sat2Graph [18]**0.69170.73510.57340.58020.11040.59510.59520.54160.56710.74740.59510.66260.7180
SPIN road mapper [5]0.78370.79880.66210.59220.10580.64220.72760.72650.72700.76210.78270.77220.7837
Ours0.81500.80920.69320.59700.07320.65870.73830.76130.74960.78450.78210.78330.7948
DeepGlobeLinkNet [10]0.80120.86760.73280.66400.08040.65250.68820.69200.69010.76750.74440.75580.7879
Orientation [8]0.82430.88570.75450.68660.10470.70120.69370.80820.74650.76240.79390.77780.8282
Ours*0.82230.89790.74940.72420.07430.74000.71500.82740.76710.79120.82830.80930.8391
", + "bbox": [ + 80, + 89, + 893, + 229 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/26afb835f5a84cf49902e1293758675f95315d8a463fa61175a66eb50e41b3e6.jpg", + "table_caption": [ + "Table 1. Quantitative results for the SpaceNet and DeepGlobe datasets." + ], + "table_footnote": [], + "table_body": "
DeepRoadMapper [29]Segmentation [22]Orientation [8]OursGround TruthSatellite Image
", + "bbox": [ + 84, + 297, + 879, + 494 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 3. APLS metric and perplexity (bits of information per edge) results for the SpaceNet dataset with provided key points that adequately capture the ground truth graph. Autoregressive order is defined in Section 3, while random order entails random permutation between edges and the order of key points within edges. To calculate perplexity for our method we use the initial predicted policy distribution, without any additional search. More details on baselines and general approach are presented in the appendix.", + "bbox": [ + 75, + 535, + 470, + 647 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/3534d6f9d77f3d939cf7206bc12e9c2c7b429b9c5b3e85699770c3140bc4062f.jpg", + "table_caption": [ + "Table 2. Qualitative results of improved connectivity. We recommend zooming in for more details." + ], + "table_footnote": [], + "table_body": "
Method MetricRandomClsGCNARMOurs
APLS0.0080.4300.5940.8940.928
Bits per edge: Autoregressive order8.743--0.5284.321
Bits per edge: Random order8.743--28.744.432
", + "bbox": [ + 78, + 648, + 478, + 714 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "dataset takes place.", + "bbox": [ + 76, + 742, + 207, + 757 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.2.1 Comparison to Baselines", + "text_level": 1, + "bbox": [ + 76, + 782, + 303, + 799 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We initially train the ARM model on ground-truth graph information by using a set of key points $\\mathcal{V}' = \\mathcal{V}$ . Even in this scenario, RL tuning increases the semantic quality of the extracted graphs as seen in Table 3. In cases where the set $\\mathcal{V}'$ is imperfect, and for reasons elaborated in Section 3, newly proposed edges may be only partially correct. Under", + "bbox": [ + 75, + 809, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "such circumstances, supervised training is infeasible, hence we rely on RL to produce the graph that leads to the maximum cumulative reward, i.e. our selected evaluation metrics. We conduct comparative analysis against the following approaches; we explore powerful CNN architectures, by training a Segmentation model with a ResNet backbone. We evaluate DeepRoadMapper [29], a model that refines previous segmentation by adding connections along possible identified paths. As done by [8] we notice that in complex scenarios, the effect of this post-processing step is not always positive. We also evaluate against LinkNet [10], and Orientation [8], which is trained to predict simultaneously road surfaces and orientation, and the relevant baselines [18, 5].", + "bbox": [ + 496, + 539, + 890, + 751 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Quantitative results in Table 1 and visual inspection in Table 2, affirm that the global context and the gradual generation incite a better understanding of the scene, leading to consistently outperforming topological metric results compared to the baselines. We remark that our predictions are more topologically consistent with fewer shortcomings, such as double roads, fragmented roads, and overconnections. This is further supplemented by comparing the statistics of the predicted spatial graphs in Fig. 7. We further", + "bbox": [ + 496, + 763, + 892, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "5414", + "bbox": [ + 482, + 946, + 514, + 957 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/37842d88c031a521df9c6fe696804a521702307cf1bb47ca41bcfa99c313e436.jpg", + "image_caption": [ + "Figure 7. (Left) Comparison of generated graph statistics, following the same post-processing, averaged across regions of $400 \\times 400$ meters in ground distance. Orientation refers to the method of [8]. (Right) The estimated Pareto front achieved through the evaluation of various runs, where a different number of MCTS simulations is being executed at each state. obj refers to an average of the APLS, Path-based f1, Junction-based f1 and Sub-graph-based f1 metrics." + ], + "image_footnote": [], + "bbox": [ + 83, + 88, + 248, + 186 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/7783eeeec9752c14d156a15f5840c3d2730140225ee8e446bc75b44c33302a6f.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 253, + 88, + 400, + 186 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/f97b8cb663405ceba97add71edc6f0c7a85ea2b40a2d193c289022895b126dba.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 403, + 89, + 558, + 186 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/aa7767f3b065226d13532d14cfc3f77db60de60704f7197aa1cacba5a42a6e4e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 562, + 90, + 714, + 186 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/59f6217c578e90777964331a4c268c7a5a5f65a975e2a5604c1ea11fd5b1f4f8.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 746, + 88, + 887, + 186 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "showcase the transferability of our model by employing it with no fine-tuning (apart from dataset-specific image normalization) on the DeepGlobe dataset. We can refine previous predictions by adding missing edges, leading to more accurate spatial graph predictions, as shown in Table 1. Our conjecture that road structures and their geometric features exhibit a high degree of recurrence across various locations and geographic regions worldwide is thus confirmed.", + "bbox": [ + 75, + 263, + 472, + 385 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.2.2 Ablation study", + "text_level": 1, + "bbox": [ + 76, + 404, + 235, + 419 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We experimented attending to image features for the two transformer modules by extracting per-patch visual features from the conditioning image $H^{\\mathrm{img}} = [h_1^{\\mathrm{img}}, h_2^{\\mathrm{img}}, \\ldots]$ , as done in the Vision Transformer [16]. This did not lead to significant improvements, which we attribute to over-fitting. In Table. 4 we highlight the relative importance of some additional components for the final predictions. As efficiency is also of particular importance to us, we further visualize the effect of varying the simulation depth of the dynamics network during training (Fig. 7 (right)). Surprisingly perhaps, our method performs consistently even with a limited number of simulations.", + "bbox": [ + 75, + 430, + 468, + 611 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In the appendix, we provide incremental results for the task of predicting road networks based on an optimal set of key points and insights concerning interpretability and further comparison to baselines based on the varying difficulty of the predicted underlying road networks. We also give more information regarding the generation of the synthetic dataset and the model architecture. Finally, we provide more implementation decisions, including details on exactly how key points and generated and how individual patch-level predictions are fused together. It is important to emphasize that our proposed method can operate effectively even when working with partially initialized predictions, making it a practical refinement approach that can be applied to existing baselines. By initializing our model based on the ARM model, we can achieve a rapid fine-tuning phase. Additionally, by utilizing the learned environment model, which avoids the need for expensive calls to the edge embedding model at each simulation step in MCTS, we can train the model even using a single GPU.", + "bbox": [ + 75, + 613, + 470, + 900 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/616d8845943d035e4be6a60301021e06fb2205a1c6a8f27827dfd820baa678c2.jpg", + "table_caption": [], + "table_footnote": [ + "P: Path-based, J: Junction-based, S: Sub-graph-based" + ], + "table_body": "
ModelAPLSP-f1J-f1S-f1
Ours0.65870.74960.78330.7948
- autoregressive pre-training-15.3%-13.7%-14.1%-13.3%
- visual features for key-points-13.4%-12.7%-12.1%-12.3%
- tree-search during evaluation-2.1%-1.4%-1.7%-1.1%
+ cross attend to image features+0.2%-0.4%-0.7%-0.3%
", + "bbox": [ + 500, + 261, + 903, + 340 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 4. Ablations study on SpaceNet dataset.", + "bbox": [ + 557, + 367, + 834, + 381 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusions", + "text_level": 1, + "bbox": [ + 500, + 421, + 627, + 436 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We presented a reinforcement learning framework for tuning autoregressive tasks for the task of generating a graph as a variable-length edge sequence, where a structured-aware decoder selects new edges by simulating action sequences into the future. Importantly, this allows the model to better capture the geometry of the targeted objects. One advantage of the proposed method is that the reward function is based on (non-continuous) metrics that are directly connected to the application in question. Our approach does not require significantly more computational resources compared to state-of-the-art supervised approaches, and in addition, it can be used to refine predictions from another given model. We also remark that the direct prediction of a graph enables the concurrent prediction of meta-information about the edges, including, for instance, the type of road (e.g. highway, primary or secondary street, biking lane).", + "bbox": [ + 496, + 454, + 890, + 712 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Our approach opens the door to several directions for future work. For example, we have assumed that a pre-defined model gives the location of key points, but one could instead augment the action space to propose new key points' locations. Other promising directions include the direct prediction of input-dependent graph primitives, e.g. T-junctions or roundabouts. Finally, we emphasize that our approach is suitable for a wide variety of applications where autoregressive models are typically used, which we intend to look into in the future. Such applications include among others, Scene Graph Generation [67, 70] and Visual reasoning/Factual Visual Question Answering [11, 35].", + "bbox": [ + 496, + 719, + 892, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "5415", + "bbox": [ + 482, + 946, + 514, + 957 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Reproducibility Statement", + "text_level": 1, + "bbox": [ + 76, + 90, + 321, + 107 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We have taken multiple steps to ensure the reproducibility of the experiments. We refer the reader to the appendix for a complete description of the training protocol. We have also released the code as part of the supplementary material.", + "bbox": [ + 76, + 114, + 468, + 176 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 188, + 173, + 204 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Samira Abnar and Willem Zuidema. Quantifying attention flow in transformers. arXiv preprint arXiv:2005.00928, 2020.", + "[2] David Acuna, Amlan Kar, and Sanja Fidler. Devil is in the edges: Learning semantic boundaries from noisy annotations. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11075-11083, 2019.", + "[3] Nicolas Audebert, Bertrand Le Saux, and Sébastien Lefèvre. Joint learning from earth observation and openstreetmap data to get faster better semantic maps. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 67-75, 2017.", + "[4] Yuntao Bai, Andy Jones, Kamal Ndousse, Amanda Askell, Anna Chen, Nova DasSarma, Dawn Drain, Stanislav Fort, Deep Ganguli, Tom Henighan, et al. Training a helpful and harmless assistant with reinforcement learning from human feedback. arXiv preprint arXiv:2204.05862, 2022.", + "[5] Wele Gedara Chaminda Bandara, Jeya Maria Jose Valanarasu, and Vishal M Patel. Spin road mapper: Extracting roads from aerial images via spatial and interaction space graph reasoning for autonomous driving. In 2022 International Conference on Robotics and Automation (ICRA), pages 343-350. IEEE, 2022.", + "[6] Meir Barzohar and David B Cooper. Automatic finding of main roads in aerial images by using geometric-stochastic models and estimation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 18(7):707-721, 1996.", + "[7] Favyen Bastani, Songtao He, Sofiane Abbar, Mohammad Al-izadeh, Hari Balakrishnan, Sanjay Chawla, Sam Madden, and David DeWitt. Roadtracer: Automatic extraction of road networks from aerial images. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4720–4728, 2018.", + "[8] Anil Batra, Suriya Singh, Guan Pang, Saikat Basu, CV Jawahar, and Manohar Paluri. Improved road connectivity by joint learning of orientation and segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10385-10393, 2019.", + "[9] Cameron B Browne, Edward Powley, Daniel Whitehouse, Simon M Lucas, Peter I Cowling, Philipp Rohlfshagen, Stephen Tavener, Diego Perez, Spyridon Samothrakis, and Simon Colton. A survey of monte carlo tree search methods. IEEE Transactions on Computational Intelligence and AI in games, 4(1):1-43, 2012.", + "[10] Abhishek Chaurasia and Eugenio Culurciello. Linknet: Exploiting encoder representations for efficient semantic segmentation. In 2017 IEEE Visual Communications and Image Processing (VCIP), pages 1-4. IEEE, 2017." + ], + "bbox": [ + 78, + 214, + 467, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[11] Xinlei Chen, Li-Jia Li, Li Fei-Fei, and Abhinav Gupta. Iterative visual reasoning beyond convolutions. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 7239-7248, 2018.", + "[12] Benjamin E Childs, James H Brodeur, and Levente Kocsis. Transpositions and move groups in monte carlo tree search. In 2008 IEEE Symposium On Computational Intelligence and Games, pages 389-395. IEEE, 2008.", + "[13] Hang Chu, Daiqing Li, David Acuna, Amlan Kar, Maria Shugrina, Xinkai Wei, Ming-Yu Liu, Antonio Torralba, and Sanja Fidler. Neural turtle graphics for modeling city road layouts. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4522-4530, 2019.", + "[14] Leonardo Citraro, Mateusz Kozinski, and Pascal Fua. Towards reliable evaluation of algorithms for road network reconstruction from aerial images. In European Conference on Computer Vision, pages 703-719. Springer, 2020.", + "[15] Ilke Demir, Krzysztof Koperski, David Lindenbaum, Guan Pang, Jing Huang, Saikat Basu, Forest Hughes, Devis Tuia, and Ramesh Raskar. Deep globe 2018: A challenge to parse the earth through satellite images. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 172-181, 2018.", + "[16] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020.", + "[17] David H Douglas and Thomas K Peucker. Algorithms for the reduction of the number of points required to represent a digitized line or its caricature. Cartographica: the international journal for geographic information and geovisualization, 10(2):112-122, 1973.", + "[18] Songtao He, Favyen Bastani, Satvat Jagwani, Mohammad Alizadeh, Hari Balakrishnan, Sanjay Chawla, Mohamed M Elshrif, Samuel Madden, and Mohammad Amin Sadeghi. Sat2graph: Road graph extraction through graph-tensor encoding. In European Conference on Computer Vision, pages 51-67. Springer, 2020.", + "[19] Stefan Hinz and Albert Baumgartner. Automatic extraction of urban road networks from multi-view aerial imagery. IS-PRS journal of photogrammetry and remote sensing, 58(1-2):83-98, 2003.", + "[20] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 9(8):1735-1780, 1997.", + "[21] Arthur Jacot, Franck Gabriel, and Clément Hongler. Neural tangent kernel: Convergence and generalization in neural networks. arXiv preprint arXiv:1806.07572, 2018.", + "[22] Pascal Kaiser, Jan Dirk Wegner, Aurélien Lucchi, Martin Jaggi, Thomas Hofmann, and Konrad Schindler. Learning aerial image segmentation from online maps. IEEE Transactions on Geoscience and Remote Sensing, 55(11):6054-6068, 2017.", + "[23] Fanjie Kong, Bohao Huang, Kyle Bradbury, and Jordan Malof. The synthinel-1 dataset: a collection of high resolution synthetic overhead imagery for building segmentation." + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "5416", + "bbox": [ + 482, + 946, + 514, + 957 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1814-1823, 2020.", + "[24] Ngan Le, Vidhiwar Singh Rathour, Kashu Yamazaki, Khoa Luu, and Marios Savvides. Deep reinforcement learning in computer vision: a comprehensive survey. Artificial Intelligence Review, pages 1-87, 2021.", + "[25] Yuxia Li, Bo Peng, Lei He, Kunlong Fan, and Ling Tong. Road segmentation of unmanned aerial vehicle remote sensing images using adversarial network with multiscale context aggregation. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 12(7):2279-2287, 2019.", + "[26] Zuoyue Li, Jan Dirk Wegner, and Aurélien Lucchi. Topological map extraction from overhead images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 1715-1724, 2019.", + "[27] Renbao Lian, Weixing Wang, Nadir Mustafa, and Liqin Huang. Road extraction methods in high-resolution remote sensing images: A comprehensive review. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 13:5489-5507, 2020.", + "[28] Jonathan Long, Evan Shelhamer, and Trevor Darrell. Fully convolutional networks for semantic segmentation. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3431-3440, 2015.", + "[29] Gellert Mattyus, Wenjie Luo, and Raquel Urtasun. Deeproadmapper: Extracting road topology from aerial images. In Proceedings of the IEEE International Conference on Computer Vision, pages 3438-3446, 2017.", + "[30] Gellert Mattyus and Raquel Urtasun. Matching adversarial networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 8024-8032, 2018.", + "[31] Gellert Mattyus, Shenlong Wang, Sanja Fidler, and Raquel Urtasun. Enhancing road maps by parsing aerial images around the world. In Proceedings of the IEEE international conference on computer vision, pages 1689-1697, 2015.", + "[32] Javier A Montoya-Zegarra, Jan D Wegner, L'ubor Ladický, and Konrad Schindler. On the evaluation of higher-order cliques for road network extraction. In 2015 Joint Urban Remote Sensing Event (JURSE), pages 1-4. IEEE, 2015.", + "[33] Philipp Moritz, Robert Nishihara, Stephanie Wang, Alexey Tumanov, Richard Liaw, Eric Liang, William Paul, Michael I Jordan, and Ion Stoica. Ray: A distributed framework for emerging ai applications. corr abs/1712.05889 (2017). arXiv preprint arXiv:1712.05889, 2017.", + "[34] Agata Mosinska, Pablo Marquez-Neila, Mateusz Kozinski, and Pascal Fua. Beyond the pixel-wise loss for topology-aware delineation. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3136–3145, 2018.", + "[35] Medhini Narasimhan, Svetlana Lazebnik, and Alexander Schwing. Out of the box: Reasoning with graph convolution nets for factual visual question answering. Advances in neural information processing systems, 31, 2018.", + "[36] Charlie Nash, Yaroslav Ganin, SM Ali Eslami, and Peter Battaglia. *Polygon: An autoregressive generative model of" + ], + "bbox": [ + 78, + 90, + 468, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "3d meshes. In International Conference on Machine Learning, pages 7220-7229. PMLR, 2020.", + "[37] Alejandro Newell, Kaiyu Yang, and Jia Deng. Stacked hourglass networks for human pose estimation. In European conference on computer vision, pages 483-499. Springer, 2016.", + "[38] Joachim Niemeyer, Jan Dirk Wegner, Clément Mallet, Franz Rottensteiner, and Uwe Soergel. Conditional random fields for urban scene classification with full waveform lidar data. In ISPRS Conference on Photogrammetric Image Analysis, pages 233-244. Springer, 2011.", + "[39] Aäron van den Oord, Nal Kalchbrenner, Oriol Vinyals, Lasse Espeholt, Alex Graves, and Koray Kavukcuoglu. Conditional image generation with pixelCNN decoders. In Proceedings of the 30th International Conference on Neural Information Processing Systems, pages 4797-4805, 2016.", + "[40] OpenStreetMap contributors. Planet dump retrieved from https://planet.osm.org . https://www.openstreetmap.org, 2017.", + "[41] Long Ouyang, Jeff Wu, Xu Jiang, Diogo Almeida, Carroll L Wainwright, Pamela Mishkin, Chong Zhang, Sandhini Agarwal, Katarina Slama, Alex Ray, et al. Training language models to follow instructions with human feedback. arXiv preprint arXiv:2203.02155, 2022.", + "[42] Wamiq Para, Paul Guerrero, Tom Kelly, Leonidas J Guibas, and Peter Wonka. Generative layout modeling using constraint graphs. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6690-6700, 2021.", + "[43] Wamiq Reyaz Para, Shariq Farooq Bhat, Paul Guerrero, Tom Kelly, Niloy Mitra, Leonidas Guibas, and Peter Wonka. Sketchgen: Generating constrained cad sketches. arXiv preprint arXiv:2106.02711, 2021.", + "[44] Tobias Pohlen, Bilal Piot, Todd Hester, Mohammad Gheshlaghi Azar, Dan Horgan, David Budden, Gabriel BarthMaron, Hado Van Hasselt, John Quan, Mel Večerík, et al. Observe and look further: Achieving consistent performance on atari. arXiv preprint arXiv:1805.11593, 2018.", + "[45] Pengda Qin, Weiran Xu, and William Yang Wang. Robust distant supervision relation extraction via deep reinforcement learning. arXiv preprint arXiv:1805.09927, 2018.", + "[46] Urs Ramer. An iterative procedure for the polygonal approximation of plane curves. Computer graphics and image processing, 1(3):244-256, 1972.", + "[47] Abdallah Saffidine, Tristan Cazenave, and Jean Méhat. Ucd: Upper confidence bound for rooted directed acyclic graphs. Knowledge-Based Systems, 34:26-33, 2012.", + "[48] Julian Schrittwieser, Ioannis Antonoglou, Thomas Hubert, Karen Simonyan, Laurent Sifre, Simon Schmitt, Arthur Guez, Edward Lockhart, Demis Hassabis, Thore Graepel, et al. Mastering atari, go, chess and shogi by planning with a learned model. Nature, 588(7839):604-609, 2020.", + "[49] John Schulman, Filip Wolski, Prafulla Dhariwal, Alec Radford, and Oleg Klimov. Proximal policy optimization algorithms. arXiv preprint arXiv:1707.06347, 2017.", + "[50] David Silver, Hado Hasselt, Matteo Hessel, Tom Schaul, Arthur Guez, Tim Harley, Gabriel Dulac-Arnold, David Reichert, Neil Rabinowitz, Andre Barreto, et al. The predictron:" + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "5417", + "bbox": [ + 482, + 946, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "End-to-end learning and planning. In International Conference on Machine Learning, pages 3191-3199. PMLR, 2017.", + "[51] David Silver, Thomas Hubert, Julian Schrittwieser, Ioannis Antonoglou, Matthew Lai, Arthur Guez, Marc Lanctot, Laurent Sifre, Dharshan Kumaran, Thore Graepel, et al. A general reinforcement learning algorithm that masters chess, shogi, and go through self-play. Science, 362(6419):1140-1144, 2018.", + "[52] Suriya Singh, Anil Batra, Guan Pang, Lorenzo Torresani, Saikat Basu, Manohar Paluri, and CV Jawahar. Self-supervised feature learning for semantic segmentation of overhead imagery. In BMVC, volume 1, page 4, 2018.", + "[53] Edward J Smith, Scott Fujimoto, Adriana Romero, and David Meger. Geometrics: Exploiting geometric structure for graph-encoded objects. arXiv preprint arXiv:1901.11461, 2019.", + "[54] André Susano Pinto, Alexander Kolesnikov, Yuge Shi, Lucas Beyer, and Xiaohua Zhai. Tuning computer vision models with task rewards. arXiv e-prints, pages arXiv-2302, 2023.", + "[55] Richard S Sutton and Andrew G Barto. Reinforcement learning: An introduction. MIT press, 2018.", + "[56] Yong-Qiang Tan, Shang-Hua Gao, Xuan-Yi Li, Ming-Ming Cheng, and Bo Ren. Vecroad: Point-based iterative graph exploration for road graphs extraction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8910-8918, 2020.", + "[57] Yuandong Tian, Jerry Ma, Qucheng Gong, Shubho Sengupta, Zhuoyuan Chen, James Pinkerton, and Larry Zitnick. Elf opengo: An analysis and open reimplementation of alphahzero. In International Conference on Machine Learning, pages 6244-6253. PMLR, 2019.", + "[58] Benigno Uria, Iain Murray, and Hugo Larochelle. A deep and tractable density estimator. In International Conference on Machine Learning, pages 467-475. PMLR, 2014.", + "[59] Aïron van den Oord, Sander Dieleman, Heiga Zen, Karen Simonyan, Oriol Vinyals, Alex Graves, Nal Kalchbrenner, Andrew Senior, and Koray Kavukcuoglu. Wavenet: A generative model for raw audio. In 9th ISCA Speech Synthesis Workshop, pages 125-125, 2016.", + "[60] Adam Van Etten, Dave Lindenbaum, and Todd M Bacastow. Spacenet: A remote sensing dataset and challenge series. arXiv preprint arXiv:1807.01232, 2018.", + "[61] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Advances in neural information processing systems, pages 5998-6008, 2017.", + "[62] Oriol Vinyals, Meire Fortunato, and Navdeep Jaitly. Pointer networks. arXiv preprint arXiv:1506.03134, 2015.", + "[63] Nanyang Wang, Yinda Zhang, Zhuwen Li, Yanwei Fu, Wei Liu, and Yu-Gang Jiang. Pixel2mesh: Generating 3d mesh models from single rgb images. In Proceedings of the European Conference on Computer Vision (ECCV), pages 52-67, 2018.", + "[64] Shenlong Wang, Min Bai, Gellert Mattyus, Hang Chu, Wenjie Luo, Bin Yang, Justin Liang, Joel Cheverie, Sanja Fidler, and Raquel Urtasun. Toronto: Seeing the world with a million eyes. arXiv preprint arXiv:1612.00423, 2016." + ], + "bbox": [ + 78, + 92, + 468, + 898 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[65] Jan D Wegner, Javier A Montoya-Zegarra, and Konrad Schindler. A higher-order crf model for road network extraction. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1698-1705, 2013.", + "[66] Christian Wiedemann, Christian Heipke, Helmut Mayer, and Olivier Jamet. Empirical evaluation of automatically extracted road axes. Empirical evaluation techniques in computer vision, 12:172-187, 1998.", + "[67] Danfei Xu, Yuke Zhu, Christopher B Choy, and Li Fei-Fei. Scene graph generation by iterative message passing. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5410-5419, 2017.", + "[68] Jingtao Xu, Yali Li, and Shengjin Wang. Adazoom: Adaptive zoom network for multi-scale object detection in large scenes. arXiv preprint arXiv:2106.10409, 2021.", + "[69] Zhenhua Xu, Yuxuan Liu, Lu Gan, Yuxiang Sun, Xinyu Wu, Ming Liu, and Lujia Wang. Rngdet: Road network graph detection by transformer in aerial images. IEEE Transactions on Geoscience and Remote Sensing, 60:1-12, 2022.", + "[70] Jianwei Yang, Jiasen Lu, Stefan Lee, Dhruv Batra, and Devi Parikh. Graph r-cnn for scene graph generation. In Proceedings of the European conference on computer vision (ECCV), pages 670-685, 2018.", + "[71] Weirui Ye, Shaohuai Liu, Thanard Kurutach, Pieter Abbeel, and Yang Gao. Mastering atari games with limited data. arXiv preprint arXiv:2111.00210, 2021." + ], + "bbox": [ + 501, + 92, + 890, + 459 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "5418", + "bbox": [ + 482, + 946, + 514, + 957 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/Mastering Spatial Graph Prediction of Road Networks/e2e1da73-cf2c-48bb-9b35-8cf5cb0f98fc_model.json b/2023/Mastering Spatial Graph Prediction of Road Networks/e2e1da73-cf2c-48bb-9b35-8cf5cb0f98fc_model.json new file mode 100644 index 0000000000000000000000000000000000000000..374517aec69f4861413293e1804d7d8c7a90e6fe --- /dev/null +++ b/2023/Mastering Spatial Graph Prediction of Road Networks/e2e1da73-cf2c-48bb-9b35-8cf5cb0f98fc_model.json @@ -0,0 +1,2257 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.044 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.048 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.209, + 0.131, + 0.764, + 0.154 + ], + "angle": 0, + "content": "Mastering Spatial Graph Prediction of Road Networks" + }, + { + "type": "image", + "bbox": [ + 0.136, + 0.18, + 0.836, + 0.419 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.422, + 0.895, + 0.452 + ], + "angle": 0, + "content": "Figure 1. Our agent interacts with the currently generated spatial graph by proposing new edges to be added. A tree-based search produces a sequence of actions that maximizes a reward function based on complex geometrics priors." + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.471, + 0.314, + 0.489 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.504, + 0.475, + 0.807 + ], + "angle": 0, + "content": "Accurately predicting road networks from satellite images requires a global understanding of the network topology. We propose to capture such high-level information by introducing a graph-based framework that given a partially generated graph, sequentially adds new edges. To deal with misalignment between the model predictions and the intended purpose, and to optimize over complex, non-continuous metrics of interest, we adopt a reinforcement learning (RL) approach that nominates modifications that maximize a cumulative reward. As opposed to standard supervised techniques that tend to be more restricted to commonly used surrogate losses, our framework yields more power and flexibility to encode problem-dependent knowledge. Empirical results on several benchmark datasets demonstrate enhanced performance and increased high-level reasoning about the graph topology when using a tree-based search. We further demonstrate the superiority of our approach in handling examples with substantial occlusion and additionally provide evidence that our predictions better match the statistical properties of the ground dataset." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.822, + 0.21, + 0.837 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.847, + 0.471, + 0.879 + ], + "angle": 0, + "content": "Road layout modelling from satellite images constitutes an important task of remote sensing, with applications in" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.473, + 0.893, + 0.73 + ], + "angle": 0, + "content": "everyday life, such as traffic flow prediction and navigation. The vast amounts of data available from the commercialization of geospatial data, in addition to the need for accurately establishing the connectivity of roads in remote areas, have led to an increased interest in the precise representation of existing road networks. By nature, these applications require structured data types that provide efficient representations to encode geometry, in this case, graphs, a de facto choice in domains such as computer graphics, virtual reality, gaming, and the film industry. These structured-graph representations are also commonly used to label recent road network datasets [60] and map repositories [40]. When dealing with complex predicted structures, however, how well the model optimizes a surrogate objective is not always the best indication of how well the model's predictions are aligned with the required task risk, i.e. the targeted final utilization." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Problems of this nature have been recently extensively studied in the regime of natural language processing, where the misalignment between training objectives for tasks such as machine translation and summarization has garnered considerable attention among the academic community, who have devoted significant efforts to its analysis and elucidation. A popular emerging technique is to first learn to imitate some example outputs and then fix any misalignment issues by using reinforcement learning to adjust the predictions based on a reward function. The reward usually comes in the form of external human evaluation [41, 4]." + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.372, + 0.902 + ], + "angle": 0, + "content": "\\(^{1}\\)Correspondence sotirios.anagnostidis@inf.ethz.ch." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.947, + 0.517, + 0.958 + ], + "angle": 0, + "content": "5408" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.102, + 0.092, + 0.287, + 0.216 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.296, + 0.092, + 0.481, + 0.216 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.493, + 0.092, + 0.673, + 0.216 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.682, + 0.092, + 0.866, + 0.216 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.219, + 0.895, + 0.277 + ], + "angle": 0, + "content": "Figure 2. Typical road network features (SpaceNet dataset). From left to right: (a) the distribution of angles between road segments leading to the same intersection is biased towards 0 and 90 degrees, i.e. parallel or perpendicular roads. The same also holds (b) for angles between random road pieces within a ground distance of 400 meters. (c) Most road vertices belong to a single road piece, with a degree of 2. (d) The average number of intersections for areas of \\(400 \\times 400\\) meters by ground distance." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.289, + 0.473, + 0.787 + ], + "angle": 0, + "content": "In this work we manifest how RL fine-tuning can greatly benefit and boost performance when producing intricate geometric predictions. For the task of road layout detection, existing methods, in contrast, mostly rely on pixel-based segmentation models that are trained on masks produced by rasterizing ground truth graphs. Performing pixel-wise segmentation, though, ignores structural features and geometric constraints inherent to the problem. As a result, minimum differences in the pixel-level output domain can have significant consequences in the proposed graph, in terms of connectivity and path distances, as manifested by the often fragmented outputs obtained after running inference on these models. In order to address these significant drawbacks, we propose a new paradigm where we (i) directly generate outputs as spatial graphs and (ii) formalize the problem as a game where we sequentially construct the output by adding edges between key points. These key points can in principle come from any off-the-shelf detector that identifies road pieces with sufficient accuracy. Our generation process avoids having to resort to cumbersome post-processing steps [8, 32] or optimize some surrogate objectives [30, 34] whose relation to the desired qualities of the final prediction can be disputed. Concurrently, the sequential decision-making strategy we propose enables us to focus interactively on different parts of the image, introducing the notion of a current state and producing reward estimates for a succession of actions. In essence, our method can be considered as a generalization of previous refinement techniques [8, 26] with three major advantages: (i) removal of the requirement for greedy decoding, (ii) ability to attend globally to the current prediction and selectively target parts of the image, and (iii) capacity to train based on demanding task-specific metrics." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.789, + 0.441, + 0.804 + ], + "angle": 0, + "content": "More precisely, our contributions are the following:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.818, + 0.47, + 0.879 + ], + "angle": 0, + "content": "- We propose a novel generic strategy for tuning autoregressive models that removes the requirement of decoding according to a pre-defined order and refines initial sampling probabilities via a tree search." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.886, + 0.471, + 0.902 + ], + "angle": 0, + "content": "- We create a synthetic benchmark dataset of pixel-level" + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.818, + 0.471, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.531, + 0.289, + 0.892, + 0.351 + ], + "angle": 0, + "content": "accurate labels of overhead satellite images for the task of road network extraction. This gives us the ability to simulate complex scenarios with occluded regions, allowing us to demonstrate improved robustness." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.357, + 0.894, + 0.403 + ], + "angle": 0, + "content": "- We confirm the wide applicability of our approach by improving the performance of existing methods on the popular SpaceNet and DeepGlobe datasets." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.42, + 0.638, + 0.436 + ], + "angle": 0, + "content": "2. Related work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.447, + 0.892, + 0.809 + ], + "angle": 0, + "content": "Initial attempts to extract road networks mainly revolved around handcrafted features and stochastic geometric models of roads [6]. Road layouts have specific characteristics regarding radiometry and topology e.g. particular junction distribution, certain general orientation, and curvature (see Fig. 2), that enable their detection even in cases with significant occlusion and uncertainty [19]. Modern approaches mostly formulate the road extraction task as a segmentation prediction task [27, 31, 3] by applying models such as Hourglass [37] or LinkNet [10]. This interpretation has significant drawbacks when evaluated against structural losses because of discontinuities in the predicted masks. Such shortcomings have been addressed by applying some additional post-processing steps, such as high-order conditional random fields [38, 65] or by training additional models that refine these initial predictions [29, 8]. Other common techniques include the optimization of an ensemble of losses. [13] rely on a directional loss and use non-maximal suppression as a thinning layer, while [8] calculate orientations of road segments. Although such auxiliary losses somewhat improve the output consistency, the fundamental issue of producing predictions in the pixel space persists. It remains impossible to overcome naturally occurring road structures, e.g. crossings of roads in different elevations, see Fig. 3." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.895, + 0.902 + ], + "angle": 0, + "content": "Previous failure cases have led to more intuitive conceptualizations of the task. Roadtracer [7], iteratively builds a road network, similar to a depth-first search approach, while [13] learn a generative model for road layouts and then apply it as a prior on top of a segmentation prediction mask. Proposed graph-based approaches encode the road" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.947, + 0.516, + 0.958 + ], + "angle": 0, + "content": "5409" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.142, + 0.09, + 0.832, + 0.226 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.23, + 0.895, + 0.273 + ], + "angle": 0, + "content": "Figure 3. (Left) Typical segmentation-based methods generate an output graph by thresholding a segmentation mask, which can however often lead to fragmented outputs. Predicting segmentation masks also makes it impossible (right) to capture complex road interactions, such as overlapping roads at different elevations." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.287, + 0.473, + 0.543 + ], + "angle": 0, + "content": "network directly as a graph, but either operate based on a constrained step-size [56] to generate new vertices or operate on a single step [18, 5], involving use-defined thresholding to post-process the final predictions. Most similar to our work, [26] predict locations of key points and define a specific order traversing them, as also done in [69]. Such autoregressive models have been recently successfully applied with the use of transformers [61] in a range of applications [36, 42, 43, 69] to model constraints between elements, where their supervised training explicitly requires tokens to be processed in a specific order. This specific order combined with the fact that only a surrogate training objective is used, introduces limitations, discussed further in the next section. In order to eliminate this order requirement and to optimize based on the desired metric, while attending globally to the currently generated graph, we propose to use RL as a suitable technique to tune these models." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.544, + 0.473, + 0.68 + ], + "angle": 0, + "content": "RL has found success in the past in computer vision applications, we refer the interested reader to [24] for a comprehensive review. These approaches mainly use RL as an auxiliary unit with the goal of improving efficiency [68] or robustness [45]. We differ from these as we use RL to tune pre-trained models with the goal of aligning with a specified task-specific reward. Such tuning was concurrently shown to significantly boost performance for tasks such as object detection, among others [54]." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.684, + 0.214, + 0.701 + ], + "angle": 0, + "content": "3. Methodology" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.709, + 0.47, + 0.83 + ], + "angle": 0, + "content": "We parametrize a road network as a graph \\(\\mathcal{G} = \\{\\mathcal{V},\\mathcal{E}\\}\\) with each vertex \\(v_{i} = [x_{i},y_{i}]^{\\top}\\in \\mathcal{V}\\) representing a key point on the road surface. The set of edges \\((v_{i},v_{j})\\in \\mathcal{E}\\) corresponds to road segments connecting these key points. We can then generate a probability distribution over roads by following a two-step process: i) generation of a set of vertices and ii) generation of a set of edges connecting them. Formally, for an image \\(\\mathcal{I}\\), a road network \\(\\mathcal{R}\\) is derived as:" + }, + { + "type": "equation", + "bbox": [ + 0.095, + 0.838, + 0.47, + 0.864 + ], + "angle": 0, + "content": "\\[\n\\mathcal {R} = \\underset {\\mathcal {V}, \\mathcal {E}} {\\arg \\max } P (\\mathcal {V}, \\mathcal {E} \\mid \\mathcal {I}) = P (\\mathcal {E} \\mid \\mathcal {V}, \\mathcal {I}) P (\\mathcal {V} \\mid \\mathcal {I}). \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.471, + 0.901 + ], + "angle": 0, + "content": "The graph nodes typically correspond to local information in an image, and we therefore resort to a CNN-based model" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.287, + 0.892, + 0.362 + ], + "angle": 0, + "content": "to extract key points, providing the set \\(\\mathcal{V}'\\), that sufficiently captures the information in the ground truth graph \\(\\mathcal{G}\\). The construction of edges, however, requires higher-level reasoning that can cope with parallel roads, junctions, occlusions, or poor image resolution, among other difficulties." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.363, + 0.892, + 0.409 + ], + "angle": 0, + "content": "Considering probabilistic models over sequences and using the chain rule, we can factorize the joint distribution as the product of a series of conditional distributions" + }, + { + "type": "equation", + "bbox": [ + 0.544, + 0.422, + 0.892, + 0.464 + ], + "angle": 0, + "content": "\\[\nP (\\mathcal {E} \\mid \\mathcal {V}, \\mathcal {I}; \\sigma) = \\prod_ {n = 1} ^ {N _ {\\mathcal {E}}} P \\left(e _ {\\sigma (n)} \\mid e _ {< \\sigma (n)}, \\mathcal {V}, \\mathcal {I}\\right), \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.478, + 0.893, + 0.658 + ], + "angle": 0, + "content": "where \\( e_{<\\sigma(n)} \\) represents \\( e_{\\sigma(1)}, e_{\\sigma(2)}, \\ldots, e_{\\sigma(n-1)} \\) and \\( \\sigma \\in S_{N_{\\mathcal{E}}} \\) denotes the set of all permutations of the integers \\( 1, 2, \\ldots, N_{\\mathcal{E}} \\), with \\( N_{\\mathcal{E}} \\) the number of edges. For our work we consider the setting where these sequences are upper bounded in length, i.e. \\( N_{\\mathcal{E}} \\leq N_{\\max} \\), since we are dealing with satellite images of fixed size. Autoregressive models (ARMs) have been used to solve similar tasks in the past by defining a fixed order of decoding [39, 59, 36, 42]. In our case, this would correspond to sorting all key points by their coordinates \\( x \\) and \\( y \\) and generating edges for each of them sequentially. We call this the autoregressive order. There are, however, two major drawbacks." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.66, + 0.895, + 0.902 + ], + "angle": 0, + "content": "First, the evaluation metrics used for this task define a buffer region in which nodes in the ground truth and the predicted graph are considered to be a match. Therefore, a newly generated edge can be only partially correct when only partially overlapping with the ground truth graph. This non-smooth feedback comes in clear contrast to the supervised training scheme of ARMs, minimization of the negative log-likelihood, that assumes perfect information regarding the key points' locations, i.e. that the sets \\(\\mathcal{V}\\) and \\(\\mathcal{V}'\\) are the same. In practice, this condition is rarely met as the exact spatial graph can be represented in arbitrarily many ways by subdividing long edges into smaller ones or due to small perturbation to key points' locations. It is thus imperative that our model can estimate the expected improvement of adding selected edges, which implicitly can also signal when to appropriately end the generation process." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.947, + 0.516, + 0.958 + ], + "angle": 0, + "content": "5410" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.258 + ], + "angle": 0, + "content": "Second, the requirement to decode according to the autoregressive order introduces a bias and limits the expressiveness of the model [58]. As a result, it can lead to failures in cases with blurry inputs or occlusions [26]. We employ RL to overcome these deficiencies and align the model with the required objective. In more detail, we tune an autoregressive model, described in Section 3.1, with the ability to search into sequences of actions in the future, as described in Section 3.2. Our novel generic strategy improves the autoregressive model without requiring significantly more computational resources." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.262, + 0.279, + 0.276 + ], + "angle": 0, + "content": "3.1. Autoregressive model" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.285, + 0.47, + 0.435 + ], + "angle": 0, + "content": "We start by introducing a base autoregressive model, illustrated in Fig. 4. Given an image and a set of key points, i.e a set of vertices \\(\\mathcal{V}'\\), our model produces a graph by sequentially predicting a list of indices corresponding to the graph's flattened, unweighted edge-list. Each forward pass produces probabilities over the set of key points, which leads to a new index after sampling. A successive pair of indices defines an edge as its two endpoints. A special end-of-sequence token is reserved to designate the end of the generation process." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.437, + 0.473, + 0.769 + ], + "angle": 0, + "content": "Following [63, 53], we begin by extracting visual features per key point, by interpolating intermediate layers of a ResNet backbone to the key points' locations, which are further augmented by position encodings of their locations. We then further process these features using two Transformer modules. The first transformer (Transformer I in Fig. 4) encodes the raw features of the key points as embeddings. The second transformer (Transformer II in Fig. 4) takes as input the currently generated edge list sequence, corresponding to the currently partially generated graph. Edges are directly mapped to the embeddings of their comprising key points, supplemented by position and type embeddings, to differentiate between them, as shown in Fig. 5 (a). An additional global image embedding also extracted by the ResNet is used to initialize the sequence. The Transformer II module produces a single hidden state, which is linked with the \\( N_{\\mathcal{V}'} + 1 \\) (corresponding to the provided key points, supplemented by the special end of the generation token) key points' embeddings by a pointer network [62], via a dot-product. This allows the generation of a probability distribution of variable length depending on the current set \\( \\mathcal{V}' \\), instead of using a fixed action space." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.772, + 0.258, + 0.787 + ], + "angle": 0, + "content": "3.2. Augmented search" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.47, + 0.902 + ], + "angle": 0, + "content": "In order to address the problems of greedy decoding (analyzed in Section 3), we frame our road extraction task as a classical Markov-decision process (MDP). The generation of a graph for every image defines an environment, where the length of the currently generated edge list determines the current step. Let \\( \\boldsymbol{o}_t \\), \\( \\alpha_t \\) and \\( r_t \\) correspond to the observation, the action, i.e. the selected key point index," + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.199 + ], + "angle": 0, + "content": "and the observed reward respectively, at time step \\( t \\). The aim is to search for a policy that maximizes the expected cumulative reward over a horizon \\( T \\), i.e., \\( \\max_{\\pi} J(\\pi) := \\mathbb{E}_{\\pi} \\left[ \\sum_{t=0}^{T-1} \\gamma^t r_t \\right] \\) where \\( \\gamma \\in (0,1] \\) indicates the discount factor and the expectation is with respect to the randomness in the policy and the transition dynamics. We set the discount factor to 1 due to the bounded time horizon." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.199, + 0.892, + 0.306 + ], + "angle": 0, + "content": "Instead of training a reward model [41], we employ established graph-theoretic metrics that also allow the definition of intermediate rewards, accelerating initial training. More formally, each action leads to the selection of a new key point, with new edges being added once every two actions. The addition of a new edge leads to a revision of the predicted graph and triggers an intermediate reward" + }, + { + "type": "equation", + "bbox": [ + 0.567, + 0.315, + 0.892, + 0.333 + ], + "angle": 0, + "content": "\\[\nr _ {t} = \\operatorname {s c} \\left(\\mathcal {G} _ {\\mathrm {g t}}, \\mathcal {G} _ {\\text {p r e d} _ {t}}\\right) - \\operatorname {s c} \\left(\\mathcal {G} _ {\\mathrm {g t}}, \\mathcal {G} _ {\\text {p r e d} _ {t - 1}}\\right), \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.34, + 0.892, + 0.401 + ], + "angle": 0, + "content": "where \\(\\operatorname{sc}(\\mathcal{G}_{\\mathrm{gt}}, \\mathcal{G}_{\\mathrm{pred}_t})\\) is a similarity score between the ground truth graph \\(\\mathcal{G}_{\\mathrm{gt}}\\) and the current estimate \\(\\mathcal{G}_{\\mathrm{pred}_t}\\). Discussion of the specific similarity scores used in practice is postponed for Section 3.3." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.401, + 0.892, + 0.492 + ], + "angle": 0, + "content": "A proper spatial graph generation entails (i) correct topology and (ii) accurate location prediction of individual roads. For the latter, intermediate vertices of degree 2 are essential. We call a road segment (RS), an ordered collection of edges, between vertices of degree \\( d(\\cdot) \\) two (or a collection of edges forming a circle):" + }, + { + "type": "equation", + "bbox": [ + 0.545, + 0.501, + 0.845, + 0.575 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathrm {R S} = \\left\\{\\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {1}}, \\boldsymbol {v} _ {\\mathrm {r s} _ {2}}\\right), \\dots , \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {k - 1}}, \\boldsymbol {v} _ {\\mathrm {r s} _ {k}}\\right) \\right\\} \\\\ \\mathrm {s . t} \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {i}}, \\boldsymbol {v} _ {\\mathrm {r s} _ {i + 1}}\\right) \\in \\mathcal {E} \\text {f o r} i = 1, \\dots , k - 1 \\\\ d \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {i}}\\right) = 2, \\text {f o r} i = 2, \\dots k - 1, \\\\ \\left(d \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {1}}\\right) \\neq 2 \\text {a n d} d \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {k}}\\right) \\neq 2 \\text {o r} \\boldsymbol {v} _ {\\mathrm {r s} _ {1}} = \\boldsymbol {v} _ {\\mathrm {r s} _ {k}}\\right). \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.584, + 0.892, + 0.902 + ], + "angle": 0, + "content": "During the progression of an episode (i.e. the sequential generation of a graph), the topological nature of the similarity scores in Eq. 3 implies that the effect of each new edge to the reward will be reflected mostly once its whole corresponding road segment has been generated. To resolve the ambiguity in the credit assignment and allow our agent to look ahead into sequences of actions, we rely on Monte Carlo Tree Search (MCTS) to simulate entire sequences of actions. We use a state-of-the-art search-based agent, MuZero [48], that constructs a learnable model of the environment dynamics, simulating transitions in this latent representation and leading to significant computational benefits. At every step, the enhanced model with its new components produces value [50] and reward estimates, which define an exploration strategy. Simulations into future sequences of actions are performed based on this strategy, helping the model to make decisions based on future outcomes, not yet experienced. Compared to a simpler PPO objective [49, 41], that in our experience did not lead to significant improvements, MCTS generates a series of simulations traversing the tree from a root node, generating more" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.947, + 0.514, + 0.958 + ], + "angle": 0, + "content": "5411" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.214, + 0.089, + 0.761, + 0.299 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.303, + 0.895, + 0.377 + ], + "angle": 0, + "content": "Figure 4. The autoregressive model with its three main components. (1) A backbone image model (ResNet) that extracts features for each key point at different scales, along with a global image embedding. (2) A key point model embeds visual and location features of distinct key points. (3) An edge embedding model relates the current edge sequence with the respective key points. Each edge token (signalled with the tokens 'index-i') corresponds to an index specifying the respective key point. A pair of such tokens designates an edge as its two endpoints. At the end of (3) we obtain a new distribution over key points that leads to an incremental update to the graph, after sampling." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.391, + 0.471, + 0.422 + ], + "angle": 0, + "content": "stable value and reward estimates. MuZero requires three distinct parts (see also Fig. 5):" + }, + { + "type": "text", + "bbox": [ + 0.09, + 0.435, + 0.473, + 0.558 + ], + "angle": 0, + "content": "1. A representation function \\( f \\) creates a latent vector of the current state \\( \\pmb{h}_t = f_\\theta(\\pmb{o}_t) \\), in our case the autoregressive model, shown in Fig. 4. Our current latent representation \\( \\pmb{h}_t \\) contains the graph's hidden state along with the key points' embeddings used to map actions to latent vectors. As key points remain the same throughout the episode, image-based features (Components (1) and (2) in Fig. 4) are only computed once." + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.563, + 0.47, + 0.669 + ], + "angle": 0, + "content": "2. A dynamics network \\( g \\), we use a simple LSTM [20], as commonly done, that predicts the effect of a new action by predicting the next hidden state and the expected reward: \\( (\\hat{h}_t, \\hat{r}_t) = g_\\theta(\\hat{h}_{t-1}, \\alpha_t) \\). We can replace \\( \\tilde{h}_{t-1} \\) with the latent representation \\( h_{t-1} \\), or its previous computed approximation \\( \\hat{h}_{t-1} \\) for tree search of depth larger than 1." + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.676, + 0.471, + 0.752 + ], + "angle": 0, + "content": "3. A prediction network \\(\\psi\\), that estimates the policy and the value for the current state \\((\\pmb{p}_{t+1}, v_t) = \\psi_\\theta(\\tilde{\\pmb{h}}_t)\\). We compute the policy via a pointer network as described in Section 3.1. Value estimates are produced by a simple multi-layer perceptron." + }, + { + "type": "list", + "bbox": [ + 0.089, + 0.435, + 0.473, + 0.752 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.903 + ], + "angle": 0, + "content": "The dynamics network guides the search and evaluates the expected reward of actions. For every newly generated edge, we also explicitly inform the network regarding the creation of new intersections and the expected relative change in the overall road surface generated via embeddings (see Fig. 5). By using the dynamics network, we bypass the expensive call to the decoder module during the search, and can instead approximate small modifications in the latent representation directly. For our experiments, the dynamics" + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.389, + 0.89, + 0.537 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.539, + 0.895, + 0.693 + ], + "angle": 0, + "content": "Figure 5. The autoregressive model generates a hidden state corresponding to the graph embedding. (a) When doing so, the edge decoder directly attends to the input key points' embeddings, augmented by position and type embeddings. (b) The prediction network uses the hidden state to produce value and policy predictions. A pointer network allows an intuitive scale of the action space by the number of key points. (c) The dynamics network simulates trajectories by estimating new hidden states and rewards. For newly generated edges, it takes as input the embeddings of the new key points, but also the degree of the two vertices involved and the length of the newly proposed generated edge." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.71, + 0.895, + 0.817 + ], + "angle": 0, + "content": "network requires up to 90 times less floating-point operations to simulate trajectories, compared to using the edge embeddings' decoder. Effectively, our method does not involve significantly more computation budget compared to the base autoregressive model. More details regarding the MuZero training and exploration are provided in Section 4 and in the appendix." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.831, + 0.683, + 0.846 + ], + "angle": 0, + "content": "3.3. Evaluation metrics" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.895, + 0.903 + ], + "angle": 0, + "content": "We adopt the same evaluation metrics both as a comparison between different methods and to determine the reward for our agent, through Eq. 3. We use the relaxed versions of" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.947, + 0.516, + 0.958 + ], + "angle": 0, + "content": "5412" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.198 + ], + "angle": 0, + "content": "precision, recall, and intersection over union for pixel-level predictions Correctness/Completeness/Quality (CCQ) [66, 64]. As graph-theoretic metrics we use APLS [60] and additionally include new metrics introduced in [14] that compare Paths, Junctions and Sub-graphs of the graphs in question, producing respectively precision, recall and \\( f_{1} \\) scores. More details can be found in the appendix." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.215, + 0.21, + 0.233 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.242, + 0.47, + 0.468 + ], + "angle": 0, + "content": "Implementation details. We resize images to \\(300 \\times 300\\) pixels, standardizing according to the training set statistics. For exploration, we initialize workers using Ray [33] that execute episodes in the environment. For training, we unroll the dynamics function for \\(t_d = 5\\) steps and use priority weights for the episode according to the differences between predicted and target values. Our algorithm can be considered as an approximate on-policy TD(\\(\\lambda\\)) [55] due to the relatively small replay buffer. We reanalyse older games [48] to provide fresher target estimates. Unvisited graph nodes are selected based on an upper confidence score, balancing exploration with exploitation, similar to [51]. We add exploration noise as Dirichlet noise and select actions based on a temperature-controlled sampling procedure, whose temperature is reduced during training." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.47, + 0.471, + 0.802 + ], + "angle": 0, + "content": "Given the limited high-quality available ground truth labels [52] and to accelerate training, we employ modifications introduced in EfficientZero [71]. We investigate adding supervision to the environment model and better initialize Q-value predictions similar to the implementation of Elf OpenGo [57]. We further scale values and rewards using an invertible transform inspired by [44]. Here, we predict support, as fully connected networks are biased towards learning low-frequency representations [21]. Selecting new actions involves generating simulations that can be done expeditiously given the small dimension of the latent space and the modest size of the dynamics network. Finally, to generate key points, we skeletonize segmentation masks provided by any baseline segmentation model, by thresholding the respective segmentation masks produced and applying RDP-simplification [17, 46]. Selecting an appropriate threshold and subdividing larger edges guarantees that the generated set \\(\\mathcal{V}'\\) adequately captures most of the ground truth road network, leaving the complexity of the problem for our model to handle. We will use the term ARM to denote the autoregressive model and Ours for the RL-tuned model." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.816, + 0.245, + 0.831 + ], + "angle": 0, + "content": "4.1. Synthetic dataset" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.469, + 0.901 + ], + "angle": 0, + "content": "Initially, a simplified setting is chosen wherein the complete governance of both the nature and intensity of the difficulty inherent in the road-extraction task can be regulated. We generate a dataset of overhead satellite images of a syn" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.09, + 0.891, + 0.278 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.281, + 0.893, + 0.379 + ], + "angle": 0, + "content": "Figure 6. (Left) Examples of fragmented outputs from the LinkNet model under cases of significant occlusion and how our approach performs in these demanding circumstances. (Right) The performance gap between our method and the same baseline is wide, based on topological spatial graph metrics, for a wide range of difficulties in the images. More details and examples are given in the supplementary material." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.394, + 0.893, + 0.529 + ], + "angle": 0, + "content": "thetic town using CityEngine1. We randomly specify vegetation of varying height and width along the side walks of the generated streets, leading inadvertently to occlusions of varying difficulty. The simulated environment allows specifying pixel-perfect masks regarding both roads and trees occluding the road surface based on the provided camera parameters [23]. We defer more details regarding the generation process and dataset examples to the supplementary material." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.531, + 0.892, + 0.742 + ], + "angle": 0, + "content": "We compare our method by training on our dataset a LinkNet model [10], a popular segmentation model that has been widely used in the remote sensing community [25]. Even in this synthetic and thus less diverse scenario, the deficiency of segmentation models to rely mostly on local information, with no explicit ability for longer-range interactions, is evident. Fig. 6 illustrates examples of such oversegmented predictions and how our approach can improve on them. We also define a 'difficulty' attribute per synthetic satellite image, quantifying the occlusions as a percentage of the ground truth road mask covered. We observe a considerable absolute improvement in topological metric scores when training our model on this synthetic dataset, compared to the baseline, for varying image difficulty." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.752, + 0.64, + 0.767 + ], + "angle": 0, + "content": "4.2. Real datasets" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.775, + 0.892, + 0.867 + ], + "angle": 0, + "content": "We assess our approach on the SpaceNet and DeepGlobe datasets. A single image is provided to our method, with a spatial graph being generated as the output. We use the same train-test splits as in [8] to promote reproducibility, while results are reported for the final combined graph on the original image scale. No pre-training on the synthetic" + }, + { + "type": "page_footnote", + "bbox": [ + 0.5, + 0.875, + 0.796, + 0.901 + ], + "angle": 0, + "content": "1https://www.esri.com/en-us/arcgis/products/arcgis-cityengine/overview" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.947, + 0.516, + 0.958 + ], + "angle": 0, + "content": "5413" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.081, + 0.09, + 0.894, + 0.23 + ], + "angle": 0, + "content": "
MethodCCQTLTSAPLS ↑Path-BasedJunction-BasedSub-graph-Based f1 ↑
corr. ↑comp. ↑qual. ↑corr. ↑2l+2s ↓pre. ↑rec. ↑f1 ↑pre. ↑rec. ↑f1 ↑
SpaceNetDeepRoadMapper [29]0.69430.68380.53860.41100.10120.51430.59580.64000.61710.62930.74430.68200.6783
Segmentation [28, 22]0.74930.70940.59690.41430.08280.54540.69090.68630.68850.71860.77100.74380.7117
LinkNet [10]0.81000.74490.64090.48940.07430.57430.67190.64600.65860.69850.78090.73740.7576
Orientation [8]0.80700.80010.68620.55940.08840.63150.71750.72800.72270.75520.75910.75710.7802
Sat2Graph [18]**0.69170.73510.57340.58020.11040.59510.59520.54160.56710.74740.59510.66260.7180
SPIN road mapper [5]0.78370.79880.66210.59220.10580.64220.72760.72650.72700.76210.78270.77220.7837
Ours0.81500.80920.69320.59700.07320.65870.73830.76130.74960.78450.78210.78330.7948
DeepGlobeLinkNet [10]0.80120.86760.73280.66400.08040.65250.68820.69200.69010.76750.74440.75580.7879
Orientation [8]0.82430.88570.75450.68660.10470.70120.69370.80820.74650.76240.79390.77780.8282
Ours*0.82230.89790.74940.72420.07430.74000.71500.82740.76710.79120.82830.80930.8391
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.086, + 0.232, + 0.581, + 0.241 + ], + "angle": 0, + "content": "* We do not fine-tune our model on the DeepGlobe dataset but instead refine predictions standardizing according to train dataset statistics." + }, + { + "type": "table_footnote", + "bbox": [ + 0.085, + 0.242, + 0.885, + 0.261 + ], + "angle": 0, + "content": "** The authors provided predictions corresponding only to a center crop of the original SpaceNet dataset images. Also, note that the test set is different from the one reported on the rest of the methods, see also the appendix. Blue: best score, Green: second best score, Gray: results reported in different test set" + }, + { + "type": "list", + "bbox": [ + 0.085, + 0.232, + 0.885, + 0.261 + ], + "angle": 0, + "content": null + }, + { + "type": "table_caption", + "bbox": [ + 0.274, + 0.275, + 0.695, + 0.289 + ], + "angle": 0, + "content": "Table 1. Quantitative results for the SpaceNet and DeepGlobe datasets." + }, + { + "type": "table", + "bbox": [ + 0.085, + 0.298, + 0.88, + 0.495 + ], + "angle": 0, + "content": "
DeepRoadMapper [29]Segmentation [22]Orientation [8]OursGround TruthSatellite Image
" + }, + { + "type": "table_caption", + "bbox": [ + 0.193, + 0.499, + 0.776, + 0.513 + ], + "angle": 0, + "content": "Table 2. Qualitative results of improved connectivity. We recommend zooming in for more details." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.536, + 0.471, + 0.648 + ], + "angle": 0, + "content": "Table 3. APLS metric and perplexity (bits of information per edge) results for the SpaceNet dataset with provided key points that adequately capture the ground truth graph. Autoregressive order is defined in Section 3, while random order entails random permutation between edges and the order of key points within edges. To calculate perplexity for our method we use the initial predicted policy distribution, without any additional search. More details on baselines and general approach are presented in the appendix." + }, + { + "type": "table", + "bbox": [ + 0.08, + 0.65, + 0.479, + 0.715 + ], + "angle": 0, + "content": "
Method MetricRandomClsGCNARMOurs
APLS0.0080.4300.5940.8940.928
Bits per edge: Autoregressive order8.743--0.5284.321
Bits per edge: Random order8.743--28.744.432
" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.743, + 0.208, + 0.758 + ], + "angle": 0, + "content": "dataset takes place." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.784, + 0.304, + 0.8 + ], + "angle": 0, + "content": "4.2.1 Comparison to Baselines" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.471, + 0.903 + ], + "angle": 0, + "content": "We initially train the ARM model on ground-truth graph information by using a set of key points \\(\\mathcal{V}' = \\mathcal{V}\\). Even in this scenario, RL tuning increases the semantic quality of the extracted graphs as seen in Table 3. In cases where the set \\(\\mathcal{V}'\\) is imperfect, and for reasons elaborated in Section 3, newly proposed edges may be only partially correct. Under" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.54, + 0.892, + 0.752 + ], + "angle": 0, + "content": "such circumstances, supervised training is infeasible, hence we rely on RL to produce the graph that leads to the maximum cumulative reward, i.e. our selected evaluation metrics. We conduct comparative analysis against the following approaches; we explore powerful CNN architectures, by training a Segmentation model with a ResNet backbone. We evaluate DeepRoadMapper [29], a model that refines previous segmentation by adding connections along possible identified paths. As done by [8] we notice that in complex scenarios, the effect of this post-processing step is not always positive. We also evaluate against LinkNet [10], and Orientation [8], which is trained to predict simultaneously road surfaces and orientation, and the relevant baselines [18, 5]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.893, + 0.903 + ], + "angle": 0, + "content": "Quantitative results in Table 1 and visual inspection in Table 2, affirm that the global context and the gradual generation incite a better understanding of the scene, leading to consistently outperforming topological metric results compared to the baselines. We remark that our predictions are more topologically consistent with fewer shortcomings, such as double roads, fragmented roads, and overconnections. This is further supplemented by comparing the statistics of the predicted spatial graphs in Fig. 7. We further" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.947, + 0.516, + 0.958 + ], + "angle": 0, + "content": "5414" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.089, + 0.249, + 0.187 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.254, + 0.089, + 0.401, + 0.187 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.405, + 0.09, + 0.56, + 0.187 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.563, + 0.091, + 0.715, + 0.187 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.747, + 0.089, + 0.888, + 0.187 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.191, + 0.894, + 0.247 + ], + "angle": 0, + "content": "Figure 7. (Left) Comparison of generated graph statistics, following the same post-processing, averaged across regions of \\(400 \\times 400\\) meters in ground distance. Orientation refers to the method of [8]. (Right) The estimated Pareto front achieved through the evaluation of various runs, where a different number of MCTS simulations is being executed at each state. obj refers to an average of the APLS, Path-based f1, Junction-based f1 and Sub-graph-based f1 metrics." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.265, + 0.473, + 0.386 + ], + "angle": 0, + "content": "showcase the transferability of our model by employing it with no fine-tuning (apart from dataset-specific image normalization) on the DeepGlobe dataset. We can refine previous predictions by adding missing edges, leading to more accurate spatial graph predictions, as shown in Table 1. Our conjecture that road structures and their geometric features exhibit a high degree of recurrence across various locations and geographic regions worldwide is thus confirmed." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.405, + 0.236, + 0.42 + ], + "angle": 0, + "content": "4.2.2 Ablation study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.431, + 0.47, + 0.612 + ], + "angle": 0, + "content": "We experimented attending to image features for the two transformer modules by extracting per-patch visual features from the conditioning image \\( H^{\\mathrm{img}} = [h_1^{\\mathrm{img}}, h_2^{\\mathrm{img}}, \\ldots] \\), as done in the Vision Transformer [16]. This did not lead to significant improvements, which we attribute to over-fitting. In Table. 4 we highlight the relative importance of some additional components for the final predictions. As efficiency is also of particular importance to us, we further visualize the effect of varying the simulation depth of the dynamics network during training (Fig. 7 (right)). Surprisingly perhaps, our method performs consistently even with a limited number of simulations." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.614, + 0.471, + 0.901 + ], + "angle": 0, + "content": "In the appendix, we provide incremental results for the task of predicting road networks based on an optimal set of key points and insights concerning interpretability and further comparison to baselines based on the varying difficulty of the predicted underlying road networks. We also give more information regarding the generation of the synthetic dataset and the model architecture. Finally, we provide more implementation decisions, including details on exactly how key points and generated and how individual patch-level predictions are fused together. It is important to emphasize that our proposed method can operate effectively even when working with partially initialized predictions, making it a practical refinement approach that can be applied to existing baselines. By initializing our model based on the ARM model, we can achieve a rapid fine-tuning phase. Additionally, by utilizing the learned environment model, which avoids the need for expensive calls to the edge embedding model at each simulation step in MCTS, we can train the model even using a single GPU." + }, + { + "type": "table", + "bbox": [ + 0.501, + 0.262, + 0.905, + 0.342 + ], + "angle": 0, + "content": "
ModelAPLSP-f1J-f1S-f1
Ours0.65870.74960.78330.7948
- autoregressive pre-training-15.3%-13.7%-14.1%-13.3%
- visual features for key-points-13.4%-12.7%-12.1%-12.3%
- tree-search during evaluation-2.1%-1.4%-1.7%-1.1%
+ cross attend to image features+0.2%-0.4%-0.7%-0.3%
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.501, + 0.345, + 0.748, + 0.357 + ], + "angle": 0, + "content": "P: Path-based, J: Junction-based, S: Sub-graph-based" + }, + { + "type": "table_caption", + "bbox": [ + 0.558, + 0.368, + 0.835, + 0.382 + ], + "angle": 0, + "content": "Table 4. Ablations study on SpaceNet dataset." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.422, + 0.628, + 0.437 + ], + "angle": 0, + "content": "5. Conclusions" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.455, + 0.892, + 0.713 + ], + "angle": 0, + "content": "We presented a reinforcement learning framework for tuning autoregressive tasks for the task of generating a graph as a variable-length edge sequence, where a structured-aware decoder selects new edges by simulating action sequences into the future. Importantly, this allows the model to better capture the geometry of the targeted objects. One advantage of the proposed method is that the reward function is based on (non-continuous) metrics that are directly connected to the application in question. Our approach does not require significantly more computational resources compared to state-of-the-art supervised approaches, and in addition, it can be used to refine predictions from another given model. We also remark that the direct prediction of a graph enables the concurrent prediction of meta-information about the edges, including, for instance, the type of road (e.g. highway, primary or secondary street, biking lane)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.893, + 0.901 + ], + "angle": 0, + "content": "Our approach opens the door to several directions for future work. For example, we have assumed that a pre-defined model gives the location of key points, but one could instead augment the action space to propose new key points' locations. Other promising directions include the direct prediction of input-dependent graph primitives, e.g. T-junctions or roundabouts. Finally, we emphasize that our approach is suitable for a wide variety of applications where autoregressive models are typically used, which we intend to look into in the future. Such applications include among others, Scene Graph Generation [67, 70] and Visual reasoning/Factual Visual Question Answering [11, 35]." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.947, + 0.516, + 0.958 + ], + "angle": 0, + "content": "5415" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.091, + 0.323, + 0.108 + ], + "angle": 0, + "content": "6. Reproducibility Statement" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.115, + 0.47, + 0.177 + ], + "angle": 0, + "content": "We have taken multiple steps to ensure the reproducibility of the experiments. We refer the reader to the appendix for a complete description of the training protocol. We have also released the code as part of the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.08, + 0.189, + 0.174, + 0.205 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.215, + 0.468, + 0.255 + ], + "angle": 0, + "content": "[1] Samira Abnar and Willem Zuidema. Quantifying attention flow in transformers. arXiv preprint arXiv:2005.00928, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.257, + 0.468, + 0.325 + ], + "angle": 0, + "content": "[2] David Acuna, Amlan Kar, and Sanja Fidler. Devil is in the edges: Learning semantic boundaries from noisy annotations. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11075-11083, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.327, + 0.468, + 0.395 + ], + "angle": 0, + "content": "[3] Nicolas Audebert, Bertrand Le Saux, and Sébastien Lefèvre. Joint learning from earth observation and openstreetmap data to get faster better semantic maps. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 67-75, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.398, + 0.468, + 0.466 + ], + "angle": 0, + "content": "[4] Yuntao Bai, Andy Jones, Kamal Ndousse, Amanda Askell, Anna Chen, Nova DasSarma, Dawn Drain, Stanislav Fort, Deep Ganguli, Tom Henighan, et al. Training a helpful and harmless assistant with reinforcement learning from human feedback. arXiv preprint arXiv:2204.05862, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.468, + 0.468, + 0.55 + ], + "angle": 0, + "content": "[5] Wele Gedara Chaminda Bandara, Jeya Maria Jose Valanarasu, and Vishal M Patel. Spin road mapper: Extracting roads from aerial images via spatial and interaction space graph reasoning for autonomous driving. In 2022 International Conference on Robotics and Automation (ICRA), pages 343-350. IEEE, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.552, + 0.468, + 0.607 + ], + "angle": 0, + "content": "[6] Meir Barzohar and David B Cooper. Automatic finding of main roads in aerial images by using geometric-stochastic models and estimation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 18(7):707-721, 1996." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.608, + 0.468, + 0.69 + ], + "angle": 0, + "content": "[7] Favyen Bastani, Songtao He, Sofiane Abbar, Mohammad Al-izadeh, Hari Balakrishnan, Sanjay Chawla, Sam Madden, and David DeWitt. Roadtracer: Automatic extraction of road networks from aerial images. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4720–4728, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.692, + 0.468, + 0.761 + ], + "angle": 0, + "content": "[8] Anil Batra, Suriya Singh, Guan Pang, Saikat Basu, CV Jawahar, and Manohar Paluri. Improved road connectivity by joint learning of orientation and segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10385-10393, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.762, + 0.468, + 0.844 + ], + "angle": 0, + "content": "[9] Cameron B Browne, Edward Powley, Daniel Whitehouse, Simon M Lucas, Peter I Cowling, Philipp Rohlfshagen, Stephen Tavener, Diego Perez, Spyridon Samothrakis, and Simon Colton. A survey of monte carlo tree search methods. IEEE Transactions on Computational Intelligence and AI in games, 4(1):1-43, 2012." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.468, + 0.901 + ], + "angle": 0, + "content": "[10] Abhishek Chaurasia and Eugenio Culurciello. Linknet: Exploiting encoder representations for efficient semantic segmentation. In 2017 IEEE Visual Communications and Image Processing (VCIP), pages 1-4. IEEE, 2017." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.215, + 0.468, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "[11] Xinlei Chen, Li-Jia Li, Li Fei-Fei, and Abhinav Gupta. Iterative visual reasoning beyond convolutions. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 7239-7248, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.15, + 0.892, + 0.205 + ], + "angle": 0, + "content": "[12] Benjamin E Childs, James H Brodeur, and Levente Kocsis. Transpositions and move groups in monte carlo tree search. In 2008 IEEE Symposium On Computational Intelligence and Games, pages 389-395. IEEE, 2008." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.207, + 0.892, + 0.275 + ], + "angle": 0, + "content": "[13] Hang Chu, Daiqing Li, David Acuna, Amlan Kar, Maria Shugrina, Xinkai Wei, Ming-Yu Liu, Antonio Torralba, and Sanja Fidler. Neural turtle graphics for modeling city road layouts. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4522-4530, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.278, + 0.892, + 0.332 + ], + "angle": 0, + "content": "[14] Leonardo Citraro, Mateusz Kozinski, and Pascal Fua. Towards reliable evaluation of algorithms for road network reconstruction from aerial images. In European Conference on Computer Vision, pages 703-719. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.334, + 0.892, + 0.417 + ], + "angle": 0, + "content": "[15] Ilke Demir, Krzysztof Koperski, David Lindenbaum, Guan Pang, Jing Huang, Saikat Basu, Forest Hughes, Devis Tuia, and Ramesh Raskar. Deep globe 2018: A challenge to parse the earth through satellite images. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 172-181, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.42, + 0.892, + 0.501 + ], + "angle": 0, + "content": "[16] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.504, + 0.892, + 0.572 + ], + "angle": 0, + "content": "[17] David H Douglas and Thomas K Peucker. Algorithms for the reduction of the number of points required to represent a digitized line or its caricature. Cartographica: the international journal for geographic information and geovisualization, 10(2):112-122, 1973." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.575, + 0.892, + 0.657 + ], + "angle": 0, + "content": "[18] Songtao He, Favyen Bastani, Satvat Jagwani, Mohammad Alizadeh, Hari Balakrishnan, Sanjay Chawla, Mohamed M Elshrif, Samuel Madden, and Mohammad Amin Sadeghi. Sat2graph: Road graph extraction through graph-tensor encoding. In European Conference on Computer Vision, pages 51-67. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.66, + 0.892, + 0.713 + ], + "angle": 0, + "content": "[19] Stefan Hinz and Albert Baumgartner. Automatic extraction of urban road networks from multi-view aerial imagery. IS-PRS journal of photogrammetry and remote sensing, 58(1-2):83-98, 2003." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.716, + 0.892, + 0.743 + ], + "angle": 0, + "content": "[20] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 9(8):1735-1780, 1997." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.746, + 0.892, + 0.786 + ], + "angle": 0, + "content": "[21] Arthur Jacot, Franck Gabriel, and Clément Hongler. Neural tangent kernel: Convergence and generalization in neural networks. arXiv preprint arXiv:1806.07572, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.789, + 0.892, + 0.856 + ], + "angle": 0, + "content": "[22] Pascal Kaiser, Jan Dirk Wegner, Aurélien Lucchi, Martin Jaggi, Thomas Hofmann, and Konrad Schindler. Learning aerial image segmentation from online maps. IEEE Transactions on Geoscience and Remote Sensing, 55(11):6054-6068, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.859, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[23] Fanjie Kong, Bohao Huang, Kyle Bradbury, and Jordan Malof. The synthinel-1 dataset: a collection of high resolution synthetic overhead imagery for building segmentation." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.947, + 0.516, + 0.958 + ], + "angle": 0, + "content": "5416" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.468, + 0.12 + ], + "angle": 0, + "content": "In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1814-1823, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.469, + 0.177 + ], + "angle": 0, + "content": "[24] Ngan Le, Vidhiwar Singh Rathour, Kashu Yamazaki, Khoa Luu, and Marios Savvides. Deep reinforcement learning in computer vision: a comprehensive survey. Artificial Intelligence Review, pages 1-87, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.179, + 0.469, + 0.26 + ], + "angle": 0, + "content": "[25] Yuxia Li, Bo Peng, Lei He, Kunlong Fan, and Ling Tong. Road segmentation of unmanned aerial vehicle remote sensing images using adversarial network with multiscale context aggregation. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 12(7):2279-2287, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.264, + 0.469, + 0.319 + ], + "angle": 0, + "content": "[26] Zuoyue Li, Jan Dirk Wegner, and Aurélien Lucchi. Topological map extraction from overhead images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 1715-1724, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.321, + 0.469, + 0.389 + ], + "angle": 0, + "content": "[27] Renbao Lian, Weixing Wang, Nadir Mustafa, and Liqin Huang. Road extraction methods in high-resolution remote sensing images: A comprehensive review. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 13:5489-5507, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.391, + 0.469, + 0.446 + ], + "angle": 0, + "content": "[28] Jonathan Long, Evan Shelhamer, and Trevor Darrell. Fully convolutional networks for semantic segmentation. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3431-3440, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.448, + 0.469, + 0.503 + ], + "angle": 0, + "content": "[29] Gellert Mattyus, Wenjie Luo, and Raquel Urtasun. Deeproadmapper: Extracting road topology from aerial images. In Proceedings of the IEEE International Conference on Computer Vision, pages 3438-3446, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.505, + 0.469, + 0.559 + ], + "angle": 0, + "content": "[30] Gellert Mattyus and Raquel Urtasun. Matching adversarial networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 8024-8032, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.562, + 0.469, + 0.617 + ], + "angle": 0, + "content": "[31] Gellert Mattyus, Shenlong Wang, Sanja Fidler, and Raquel Urtasun. Enhancing road maps by parsing aerial images around the world. In Proceedings of the IEEE international conference on computer vision, pages 1689-1697, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.619, + 0.469, + 0.673 + ], + "angle": 0, + "content": "[32] Javier A Montoya-Zegarra, Jan D Wegner, L'ubor Ladický, and Konrad Schindler. On the evaluation of higher-order cliques for road network extraction. In 2015 Joint Urban Remote Sensing Event (JURSE), pages 1-4. IEEE, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.676, + 0.469, + 0.744 + ], + "angle": 0, + "content": "[33] Philipp Moritz, Robert Nishihara, Stephanie Wang, Alexey Tumanov, Richard Liaw, Eric Liang, William Paul, Michael I Jordan, and Ion Stoica. Ray: A distributed framework for emerging ai applications. corr abs/1712.05889 (2017). arXiv preprint arXiv:1712.05889, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.746, + 0.469, + 0.813 + ], + "angle": 0, + "content": "[34] Agata Mosinska, Pablo Marquez-Neila, Mateusz Kozinski, and Pascal Fua. Beyond the pixel-wise loss for topology-aware delineation. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3136–3145, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.817, + 0.469, + 0.871 + ], + "angle": 0, + "content": "[35] Medhini Narasimhan, Svetlana Lazebnik, and Alexander Schwing. Out of the box: Reasoning with graph convolution nets for factual visual question answering. Advances in neural information processing systems, 31, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.874, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[36] Charlie Nash, Yaroslav Ganin, SM Ali Eslami, and Peter Battaglia. *Polygon: An autoregressive generative model of" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.89, + 0.12 + ], + "angle": 0, + "content": "3d meshes. In International Conference on Machine Learning, pages 7220-7229. PMLR, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.122, + 0.892, + 0.164 + ], + "angle": 0, + "content": "[37] Alejandro Newell, Kaiyu Yang, and Jia Deng. Stacked hourglass networks for human pose estimation. In European conference on computer vision, pages 483-499. Springer, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.165, + 0.892, + 0.234 + ], + "angle": 0, + "content": "[38] Joachim Niemeyer, Jan Dirk Wegner, Clément Mallet, Franz Rottensteiner, and Uwe Soergel. Conditional random fields for urban scene classification with full waveform lidar data. In ISPRS Conference on Photogrammetric Image Analysis, pages 233-244. Springer, 2011." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.236, + 0.892, + 0.304 + ], + "angle": 0, + "content": "[39] Aäron van den Oord, Nal Kalchbrenner, Oriol Vinyals, Lasse Espeholt, Alex Graves, and Koray Kavukcuoglu. Conditional image generation with pixelCNN decoders. In Proceedings of the 30th International Conference on Neural Information Processing Systems, pages 4797-4805, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.305, + 0.892, + 0.347 + ], + "angle": 0, + "content": "[40] OpenStreetMap contributors. Planet dump retrieved from https://planet.osm.org . https://www.openstreetmap.org, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.349, + 0.892, + 0.417 + ], + "angle": 0, + "content": "[41] Long Ouyang, Jeff Wu, Xu Jiang, Diogo Almeida, Carroll L Wainwright, Pamela Mishkin, Chong Zhang, Sandhini Agarwal, Katarina Slama, Alex Ray, et al. Training language models to follow instructions with human feedback. arXiv preprint arXiv:2203.02155, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.42, + 0.892, + 0.487 + ], + "angle": 0, + "content": "[42] Wamiq Para, Paul Guerrero, Tom Kelly, Leonidas J Guibas, and Peter Wonka. Generative layout modeling using constraint graphs. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6690-6700, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.49, + 0.892, + 0.545 + ], + "angle": 0, + "content": "[43] Wamiq Reyaz Para, Shariq Farooq Bhat, Paul Guerrero, Tom Kelly, Niloy Mitra, Leonidas Guibas, and Peter Wonka. Sketchgen: Generating constrained cad sketches. arXiv preprint arXiv:2106.02711, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.547, + 0.892, + 0.615 + ], + "angle": 0, + "content": "[44] Tobias Pohlen, Bilal Piot, Todd Hester, Mohammad Gheshlaghi Azar, Dan Horgan, David Budden, Gabriel BarthMaron, Hado Van Hasselt, John Quan, Mel Večerík, et al. Observe and look further: Achieving consistent performance on atari. arXiv preprint arXiv:1805.11593, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.617, + 0.892, + 0.657 + ], + "angle": 0, + "content": "[45] Pengda Qin, Weiran Xu, and William Yang Wang. Robust distant supervision relation extraction via deep reinforcement learning. arXiv preprint arXiv:1805.09927, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.661, + 0.892, + 0.701 + ], + "angle": 0, + "content": "[46] Urs Ramer. An iterative procedure for the polygonal approximation of plane curves. Computer graphics and image processing, 1(3):244-256, 1972." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.704, + 0.892, + 0.744 + ], + "angle": 0, + "content": "[47] Abdallah Saffidine, Tristan Cazenave, and Jean Méhat. Ucd: Upper confidence bound for rooted directed acyclic graphs. Knowledge-Based Systems, 34:26-33, 2012." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.746, + 0.892, + 0.814 + ], + "angle": 0, + "content": "[48] Julian Schrittwieser, Ioannis Antonoglou, Thomas Hubert, Karen Simonyan, Laurent Sifre, Simon Schmitt, Arthur Guez, Edward Lockhart, Demis Hassabis, Thore Graepel, et al. Mastering atari, go, chess and shogi by planning with a learned model. Nature, 588(7839):604-609, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.817, + 0.892, + 0.858 + ], + "angle": 0, + "content": "[49] John Schulman, Filip Wolski, Prafulla Dhariwal, Alec Radford, and Oleg Klimov. Proximal policy optimization algorithms. arXiv preprint arXiv:1707.06347, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.86, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[50] David Silver, Hado Hasselt, Matteo Hessel, Tom Schaul, Arthur Guez, Tim Harley, Gabriel Dulac-Arnold, David Reichert, Neil Rabinowitz, Andre Barreto, et al. The predictron:" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.947, + 0.515, + 0.957 + ], + "angle": 0, + "content": "5417" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.093, + 0.468, + 0.12 + ], + "angle": 0, + "content": "End-to-end learning and planning. In International Conference on Machine Learning, pages 3191-3199. PMLR, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.469, + 0.204 + ], + "angle": 0, + "content": "[51] David Silver, Thomas Hubert, Julian Schrittwieser, Ioannis Antonoglou, Matthew Lai, Arthur Guez, Marc Lanctot, Laurent Sifre, Dharshan Kumaran, Thore Graepel, et al. A general reinforcement learning algorithm that masters chess, shogi, and go through self-play. Science, 362(6419):1140-1144, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.207, + 0.469, + 0.262 + ], + "angle": 0, + "content": "[52] Suriya Singh, Anil Batra, Guan Pang, Lorenzo Torresani, Saikat Basu, Manohar Paluri, and CV Jawahar. Self-supervised feature learning for semantic segmentation of overhead imagery. In BMVC, volume 1, page 4, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.264, + 0.469, + 0.317 + ], + "angle": 0, + "content": "[53] Edward J Smith, Scott Fujimoto, Adriana Romero, and David Meger. Geometrics: Exploiting geometric structure for graph-encoded objects. arXiv preprint arXiv:1901.11461, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.32, + 0.469, + 0.361 + ], + "angle": 0, + "content": "[54] André Susano Pinto, Alexander Kolesnikov, Yuge Shi, Lucas Beyer, and Xiaohua Zhai. Tuning computer vision models with task rewards. arXiv e-prints, pages arXiv-2302, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.363, + 0.469, + 0.39 + ], + "angle": 0, + "content": "[55] Richard S Sutton and Andrew G Barto. Reinforcement learning: An introduction. MIT press, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.392, + 0.469, + 0.46 + ], + "angle": 0, + "content": "[56] Yong-Qiang Tan, Shang-Hua Gao, Xuan-Yi Li, Ming-Ming Cheng, and Bo Ren. Vecroad: Point-based iterative graph exploration for road graphs extraction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8910-8918, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.463, + 0.469, + 0.531 + ], + "angle": 0, + "content": "[57] Yuandong Tian, Jerry Ma, Qucheng Gong, Shubho Sengupta, Zhuoyuan Chen, James Pinkerton, and Larry Zitnick. Elf opengo: An analysis and open reimplementation of alphahzero. In International Conference on Machine Learning, pages 6244-6253. PMLR, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.533, + 0.469, + 0.574 + ], + "angle": 0, + "content": "[58] Benigno Uria, Iain Murray, and Hugo Larochelle. A deep and tractable density estimator. In International Conference on Machine Learning, pages 467-475. PMLR, 2014." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.577, + 0.469, + 0.645 + ], + "angle": 0, + "content": "[59] Aïron van den Oord, Sander Dieleman, Heiga Zen, Karen Simonyan, Oriol Vinyals, Alex Graves, Nal Kalchbrenner, Andrew Senior, and Koray Kavukcuoglu. Wavenet: A generative model for raw audio. In 9th ISCA Speech Synthesis Workshop, pages 125-125, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.647, + 0.469, + 0.687 + ], + "angle": 0, + "content": "[60] Adam Van Etten, Dave Lindenbaum, and Todd M Bacastow. Spacenet: A remote sensing dataset and challenge series. arXiv preprint arXiv:1807.01232, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.69, + 0.469, + 0.744 + ], + "angle": 0, + "content": "[61] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Advances in neural information processing systems, pages 5998-6008, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.747, + 0.469, + 0.773 + ], + "angle": 0, + "content": "[62] Oriol Vinyals, Meire Fortunato, and Navdeep Jaitly. Pointer networks. arXiv preprint arXiv:1506.03134, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.776, + 0.469, + 0.843 + ], + "angle": 0, + "content": "[63] Nanyang Wang, Yinda Zhang, Zhuwen Li, Yanwei Fu, Wei Liu, and Yu-Gang Jiang. Pixel2mesh: Generating 3d mesh models from single rgb images. In Proceedings of the European Conference on Computer Vision (ECCV), pages 52-67, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.469, + 0.9 + ], + "angle": 0, + "content": "[64] Shenlong Wang, Min Bai, Gellert Mattyus, Hang Chu, Wenjie Luo, Bin Yang, Justin Liang, Joel Cheverie, Sanja Fidler, and Raquel Urtasun. Toronto: Seeing the world with a million eyes. arXiv preprint arXiv:1612.00423, 2016." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.093, + 0.469, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.148 + ], + "angle": 0, + "content": "[65] Jan D Wegner, Javier A Montoya-Zegarra, and Konrad Schindler. A higher-order crf model for road network extraction. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1698-1705, 2013." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.151, + 0.892, + 0.204 + ], + "angle": 0, + "content": "[66] Christian Wiedemann, Christian Heipke, Helmut Mayer, and Olivier Jamet. Empirical evaluation of automatically extracted road axes. Empirical evaluation techniques in computer vision, 12:172-187, 1998." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.207, + 0.892, + 0.261 + ], + "angle": 0, + "content": "[67] Danfei Xu, Yuke Zhu, Christopher B Choy, and Li Fei-Fei. Scene graph generation by iterative message passing. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5410-5419, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.264, + 0.892, + 0.303 + ], + "angle": 0, + "content": "[68] Jingtao Xu, Yali Li, and Shengjin Wang. Adazoom: Adaptive zoom network for multi-scale object detection in large scenes. arXiv preprint arXiv:2106.10409, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.306, + 0.892, + 0.36 + ], + "angle": 0, + "content": "[69] Zhenhua Xu, Yuxuan Liu, Lu Gan, Yuxiang Sun, Xinyu Wu, Ming Liu, and Lujia Wang. Rngdet: Road network graph detection by transformer in aerial images. IEEE Transactions on Geoscience and Remote Sensing, 60:1-12, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.363, + 0.892, + 0.417 + ], + "angle": 0, + "content": "[70] Jianwei Yang, Jiasen Lu, Stefan Lee, Dhruv Batra, and Devi Parikh. Graph r-cnn for scene graph generation. In Proceedings of the European conference on computer vision (ECCV), pages 670-685, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.419, + 0.892, + 0.46 + ], + "angle": 0, + "content": "[71] Weirui Ye, Shaohuai Liu, Thanard Kurutach, Pieter Abbeel, and Yang Gao. Mastering atari games with limited data. arXiv preprint arXiv:2111.00210, 2021." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.46 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.947, + 0.516, + 0.958 + ], + "angle": 0, + "content": "5418" + } + ] +] \ No newline at end of file diff --git a/2023/Mastering Spatial Graph Prediction of Road Networks/e2e1da73-cf2c-48bb-9b35-8cf5cb0f98fc_origin.pdf b/2023/Mastering Spatial Graph Prediction of Road Networks/e2e1da73-cf2c-48bb-9b35-8cf5cb0f98fc_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..746b1696666b5d82b0642eb2706903bdb89c2e59 --- /dev/null +++ b/2023/Mastering Spatial Graph Prediction of Road Networks/e2e1da73-cf2c-48bb-9b35-8cf5cb0f98fc_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:a6320a11edba4048e1ac15f44dfea75834a610ae3d4d1e96102e6a37eb5db41f +size 16712729 diff --git a/2023/Mastering Spatial Graph Prediction of Road Networks/full.md b/2023/Mastering Spatial Graph Prediction of Road Networks/full.md new file mode 100644 index 0000000000000000000000000000000000000000..0fae0b66fb619f3b5ec5585949e5aae4480a6c63 --- /dev/null +++ b/2023/Mastering Spatial Graph Prediction of Road Networks/full.md @@ -0,0 +1,286 @@ +# Mastering Spatial Graph Prediction of Road Networks + +![](images/39e1605452bce5ce8cf84949b7a25e8c56a8e5a386b9bed9b83b78f260088d1b.jpg) +Figure 1. Our agent interacts with the currently generated spatial graph by proposing new edges to be added. A tree-based search produces a sequence of actions that maximizes a reward function based on complex geometrics priors. + +# Abstract + +Accurately predicting road networks from satellite images requires a global understanding of the network topology. We propose to capture such high-level information by introducing a graph-based framework that given a partially generated graph, sequentially adds new edges. To deal with misalignment between the model predictions and the intended purpose, and to optimize over complex, non-continuous metrics of interest, we adopt a reinforcement learning (RL) approach that nominates modifications that maximize a cumulative reward. As opposed to standard supervised techniques that tend to be more restricted to commonly used surrogate losses, our framework yields more power and flexibility to encode problem-dependent knowledge. Empirical results on several benchmark datasets demonstrate enhanced performance and increased high-level reasoning about the graph topology when using a tree-based search. We further demonstrate the superiority of our approach in handling examples with substantial occlusion and additionally provide evidence that our predictions better match the statistical properties of the ground dataset. + +# 1. Introduction + +Road layout modelling from satellite images constitutes an important task of remote sensing, with applications in + +everyday life, such as traffic flow prediction and navigation. The vast amounts of data available from the commercialization of geospatial data, in addition to the need for accurately establishing the connectivity of roads in remote areas, have led to an increased interest in the precise representation of existing road networks. By nature, these applications require structured data types that provide efficient representations to encode geometry, in this case, graphs, a de facto choice in domains such as computer graphics, virtual reality, gaming, and the film industry. These structured-graph representations are also commonly used to label recent road network datasets [60] and map repositories [40]. When dealing with complex predicted structures, however, how well the model optimizes a surrogate objective is not always the best indication of how well the model's predictions are aligned with the required task risk, i.e. the targeted final utilization. + +Problems of this nature have been recently extensively studied in the regime of natural language processing, where the misalignment between training objectives for tasks such as machine translation and summarization has garnered considerable attention among the academic community, who have devoted significant efforts to its analysis and elucidation. A popular emerging technique is to first learn to imitate some example outputs and then fix any misalignment issues by using reinforcement learning to adjust the predictions based on a reward function. The reward usually comes in the form of external human evaluation [41, 4]. + +![](images/289d74b5d8a6c6159644d8abbf0c30870bb8988556e3286346230df1ae30e3c4.jpg) +Figure 2. Typical road network features (SpaceNet dataset). From left to right: (a) the distribution of angles between road segments leading to the same intersection is biased towards 0 and 90 degrees, i.e. parallel or perpendicular roads. The same also holds (b) for angles between random road pieces within a ground distance of 400 meters. (c) Most road vertices belong to a single road piece, with a degree of 2. (d) The average number of intersections for areas of $400 \times 400$ meters by ground distance. + +![](images/fac45254ed5c48ba27e03a969eeb3008f80a5492ff823b3b086b98f006c1060e.jpg) + +![](images/aa09bbcd1294069573c2a851e307fe6f114f5107efd8469ab08fd1ca396d7aa4.jpg) + +![](images/3ea6de973e7faf2eb4f3627c7a3e60158c58eadb5ce6bd0b7f6681e886e91b41.jpg) + +In this work we manifest how RL fine-tuning can greatly benefit and boost performance when producing intricate geometric predictions. For the task of road layout detection, existing methods, in contrast, mostly rely on pixel-based segmentation models that are trained on masks produced by rasterizing ground truth graphs. Performing pixel-wise segmentation, though, ignores structural features and geometric constraints inherent to the problem. As a result, minimum differences in the pixel-level output domain can have significant consequences in the proposed graph, in terms of connectivity and path distances, as manifested by the often fragmented outputs obtained after running inference on these models. In order to address these significant drawbacks, we propose a new paradigm where we (i) directly generate outputs as spatial graphs and (ii) formalize the problem as a game where we sequentially construct the output by adding edges between key points. These key points can in principle come from any off-the-shelf detector that identifies road pieces with sufficient accuracy. Our generation process avoids having to resort to cumbersome post-processing steps [8, 32] or optimize some surrogate objectives [30, 34] whose relation to the desired qualities of the final prediction can be disputed. Concurrently, the sequential decision-making strategy we propose enables us to focus interactively on different parts of the image, introducing the notion of a current state and producing reward estimates for a succession of actions. In essence, our method can be considered as a generalization of previous refinement techniques [8, 26] with three major advantages: (i) removal of the requirement for greedy decoding, (ii) ability to attend globally to the current prediction and selectively target parts of the image, and (iii) capacity to train based on demanding task-specific metrics. + +More precisely, our contributions are the following: + +- We propose a novel generic strategy for tuning autoregressive models that removes the requirement of decoding according to a pre-defined order and refines initial sampling probabilities via a tree search. +- We create a synthetic benchmark dataset of pixel-level + +accurate labels of overhead satellite images for the task of road network extraction. This gives us the ability to simulate complex scenarios with occluded regions, allowing us to demonstrate improved robustness. + +- We confirm the wide applicability of our approach by improving the performance of existing methods on the popular SpaceNet and DeepGlobe datasets. + +# 2. Related work + +Initial attempts to extract road networks mainly revolved around handcrafted features and stochastic geometric models of roads [6]. Road layouts have specific characteristics regarding radiometry and topology e.g. particular junction distribution, certain general orientation, and curvature (see Fig. 2), that enable their detection even in cases with significant occlusion and uncertainty [19]. Modern approaches mostly formulate the road extraction task as a segmentation prediction task [27, 31, 3] by applying models such as Hourglass [37] or LinkNet [10]. This interpretation has significant drawbacks when evaluated against structural losses because of discontinuities in the predicted masks. Such shortcomings have been addressed by applying some additional post-processing steps, such as high-order conditional random fields [38, 65] or by training additional models that refine these initial predictions [29, 8]. Other common techniques include the optimization of an ensemble of losses. [13] rely on a directional loss and use non-maximal suppression as a thinning layer, while [8] calculate orientations of road segments. Although such auxiliary losses somewhat improve the output consistency, the fundamental issue of producing predictions in the pixel space persists. It remains impossible to overcome naturally occurring road structures, e.g. crossings of roads in different elevations, see Fig. 3. + +Previous failure cases have led to more intuitive conceptualizations of the task. Roadtracer [7], iteratively builds a road network, similar to a depth-first search approach, while [13] learn a generative model for road layouts and then apply it as a prior on top of a segmentation prediction mask. Proposed graph-based approaches encode the road + +![](images/ae7401aa94dbf125c2a87995e1e91ac77a5055cc773f910726b66a16bdfa70c5.jpg) +Figure 3. (Left) Typical segmentation-based methods generate an output graph by thresholding a segmentation mask, which can however often lead to fragmented outputs. Predicting segmentation masks also makes it impossible (right) to capture complex road interactions, such as overlapping roads at different elevations. + +network directly as a graph, but either operate based on a constrained step-size [56] to generate new vertices or operate on a single step [18, 5], involving use-defined thresholding to post-process the final predictions. Most similar to our work, [26] predict locations of key points and define a specific order traversing them, as also done in [69]. Such autoregressive models have been recently successfully applied with the use of transformers [61] in a range of applications [36, 42, 43, 69] to model constraints between elements, where their supervised training explicitly requires tokens to be processed in a specific order. This specific order combined with the fact that only a surrogate training objective is used, introduces limitations, discussed further in the next section. In order to eliminate this order requirement and to optimize based on the desired metric, while attending globally to the currently generated graph, we propose to use RL as a suitable technique to tune these models. + +RL has found success in the past in computer vision applications, we refer the interested reader to [24] for a comprehensive review. These approaches mainly use RL as an auxiliary unit with the goal of improving efficiency [68] or robustness [45]. We differ from these as we use RL to tune pre-trained models with the goal of aligning with a specified task-specific reward. Such tuning was concurrently shown to significantly boost performance for tasks such as object detection, among others [54]. + +# 3. Methodology + +We parametrize a road network as a graph $\mathcal{G} = \{\mathcal{V},\mathcal{E}\}$ with each vertex $v_{i} = [x_{i},y_{i}]^{\top}\in \mathcal{V}$ representing a key point on the road surface. The set of edges $(v_{i},v_{j})\in \mathcal{E}$ corresponds to road segments connecting these key points. We can then generate a probability distribution over roads by following a two-step process: i) generation of a set of vertices and ii) generation of a set of edges connecting them. Formally, for an image $\mathcal{I}$ , a road network $\mathcal{R}$ is derived as: + +$$ +\mathcal {R} = \underset {\mathcal {V}, \mathcal {E}} {\arg \max } P (\mathcal {V}, \mathcal {E} \mid \mathcal {I}) = P (\mathcal {E} \mid \mathcal {V}, \mathcal {I}) P (\mathcal {V} \mid \mathcal {I}). \tag {1} +$$ + +The graph nodes typically correspond to local information in an image, and we therefore resort to a CNN-based model + +to extract key points, providing the set $\mathcal{V}'$ , that sufficiently captures the information in the ground truth graph $\mathcal{G}$ . The construction of edges, however, requires higher-level reasoning that can cope with parallel roads, junctions, occlusions, or poor image resolution, among other difficulties. + +Considering probabilistic models over sequences and using the chain rule, we can factorize the joint distribution as the product of a series of conditional distributions + +$$ +P (\mathcal {E} \mid \mathcal {V}, \mathcal {I}; \sigma) = \prod_ {n = 1} ^ {N _ {\mathcal {E}}} P \left(e _ {\sigma (n)} \mid e _ {< \sigma (n)}, \mathcal {V}, \mathcal {I}\right), \tag {2} +$$ + +where $e_{<\sigma(n)}$ represents $e_{\sigma(1)}, e_{\sigma(2)}, \ldots, e_{\sigma(n-1)}$ and $\sigma \in S_{N_{\mathcal{E}}}$ denotes the set of all permutations of the integers $1, 2, \ldots, N_{\mathcal{E}}$ , with $N_{\mathcal{E}}$ the number of edges. For our work we consider the setting where these sequences are upper bounded in length, i.e. $N_{\mathcal{E}} \leq N_{\max}$ , since we are dealing with satellite images of fixed size. Autoregressive models (ARMs) have been used to solve similar tasks in the past by defining a fixed order of decoding [39, 59, 36, 42]. In our case, this would correspond to sorting all key points by their coordinates $x$ and $y$ and generating edges for each of them sequentially. We call this the autoregressive order. There are, however, two major drawbacks. + +First, the evaluation metrics used for this task define a buffer region in which nodes in the ground truth and the predicted graph are considered to be a match. Therefore, a newly generated edge can be only partially correct when only partially overlapping with the ground truth graph. This non-smooth feedback comes in clear contrast to the supervised training scheme of ARMs, minimization of the negative log-likelihood, that assumes perfect information regarding the key points' locations, i.e. that the sets $\mathcal{V}$ and $\mathcal{V}'$ are the same. In practice, this condition is rarely met as the exact spatial graph can be represented in arbitrarily many ways by subdividing long edges into smaller ones or due to small perturbation to key points' locations. It is thus imperative that our model can estimate the expected improvement of adding selected edges, which implicitly can also signal when to appropriately end the generation process. + +Second, the requirement to decode according to the autoregressive order introduces a bias and limits the expressiveness of the model [58]. As a result, it can lead to failures in cases with blurry inputs or occlusions [26]. We employ RL to overcome these deficiencies and align the model with the required objective. In more detail, we tune an autoregressive model, described in Section 3.1, with the ability to search into sequences of actions in the future, as described in Section 3.2. Our novel generic strategy improves the autoregressive model without requiring significantly more computational resources. + +# 3.1. Autoregressive model + +We start by introducing a base autoregressive model, illustrated in Fig. 4. Given an image and a set of key points, i.e a set of vertices $\mathcal{V}'$ , our model produces a graph by sequentially predicting a list of indices corresponding to the graph's flattened, unweighted edge-list. Each forward pass produces probabilities over the set of key points, which leads to a new index after sampling. A successive pair of indices defines an edge as its two endpoints. A special end-of-sequence token is reserved to designate the end of the generation process. + +Following [63, 53], we begin by extracting visual features per key point, by interpolating intermediate layers of a ResNet backbone to the key points' locations, which are further augmented by position encodings of their locations. We then further process these features using two Transformer modules. The first transformer (Transformer I in Fig. 4) encodes the raw features of the key points as embeddings. The second transformer (Transformer II in Fig. 4) takes as input the currently generated edge list sequence, corresponding to the currently partially generated graph. Edges are directly mapped to the embeddings of their comprising key points, supplemented by position and type embeddings, to differentiate between them, as shown in Fig. 5 (a). An additional global image embedding also extracted by the ResNet is used to initialize the sequence. The Transformer II module produces a single hidden state, which is linked with the $N_{\mathcal{V}'} + 1$ (corresponding to the provided key points, supplemented by the special end of the generation token) key points' embeddings by a pointer network [62], via a dot-product. This allows the generation of a probability distribution of variable length depending on the current set $\mathcal{V}'$ , instead of using a fixed action space. + +# 3.2. Augmented search + +In order to address the problems of greedy decoding (analyzed in Section 3), we frame our road extraction task as a classical Markov-decision process (MDP). The generation of a graph for every image defines an environment, where the length of the currently generated edge list determines the current step. Let $\boldsymbol{o}_t$ , $\alpha_t$ and $r_t$ correspond to the observation, the action, i.e. the selected key point index, + +and the observed reward respectively, at time step $t$ . The aim is to search for a policy that maximizes the expected cumulative reward over a horizon $T$ , i.e., $\max_{\pi} J(\pi) := \mathbb{E}_{\pi} \left[ \sum_{t=0}^{T-1} \gamma^t r_t \right]$ where $\gamma \in (0,1]$ indicates the discount factor and the expectation is with respect to the randomness in the policy and the transition dynamics. We set the discount factor to 1 due to the bounded time horizon. + +Instead of training a reward model [41], we employ established graph-theoretic metrics that also allow the definition of intermediate rewards, accelerating initial training. More formally, each action leads to the selection of a new key point, with new edges being added once every two actions. The addition of a new edge leads to a revision of the predicted graph and triggers an intermediate reward + +$$ +r _ {t} = \operatorname {s c} \left(\mathcal {G} _ {\mathrm {g t}}, \mathcal {G} _ {\text {p r e d} _ {t}}\right) - \operatorname {s c} \left(\mathcal {G} _ {\mathrm {g t}}, \mathcal {G} _ {\text {p r e d} _ {t - 1}}\right), \tag {3} +$$ + +where $\operatorname{sc}(\mathcal{G}_{\mathrm{gt}}, \mathcal{G}_{\mathrm{pred}_t})$ is a similarity score between the ground truth graph $\mathcal{G}_{\mathrm{gt}}$ and the current estimate $\mathcal{G}_{\mathrm{pred}_t}$ . Discussion of the specific similarity scores used in practice is postponed for Section 3.3. + +A proper spatial graph generation entails (i) correct topology and (ii) accurate location prediction of individual roads. For the latter, intermediate vertices of degree 2 are essential. We call a road segment (RS), an ordered collection of edges, between vertices of degree $d(\cdot)$ two (or a collection of edges forming a circle): + +$$ +\begin{array}{l} \mathrm {R S} = \left\{\left(\boldsymbol {v} _ {\mathrm {r s} _ {1}}, \boldsymbol {v} _ {\mathrm {r s} _ {2}}\right), \dots , \left(\boldsymbol {v} _ {\mathrm {r s} _ {k - 1}}, \boldsymbol {v} _ {\mathrm {r s} _ {k}}\right) \right\} \\ \mathrm {s . t} \left(\boldsymbol {v} _ {\mathrm {r s} _ {i}}, \boldsymbol {v} _ {\mathrm {r s} _ {i + 1}}\right) \in \mathcal {E} \text {f o r} i = 1, \dots , k - 1 \\ d \left(\boldsymbol {v} _ {\mathrm {r s} _ {i}}\right) = 2, \text {f o r} i = 2, \dots k - 1, \\ \left(d \left(\boldsymbol {v} _ {\mathrm {r s} _ {1}}\right) \neq 2 \text {a n d} d \left(\boldsymbol {v} _ {\mathrm {r s} _ {k}}\right) \neq 2 \text {o r} \boldsymbol {v} _ {\mathrm {r s} _ {1}} = \boldsymbol {v} _ {\mathrm {r s} _ {k}}\right). \\ \end{array} +$$ + +During the progression of an episode (i.e. the sequential generation of a graph), the topological nature of the similarity scores in Eq. 3 implies that the effect of each new edge to the reward will be reflected mostly once its whole corresponding road segment has been generated. To resolve the ambiguity in the credit assignment and allow our agent to look ahead into sequences of actions, we rely on Monte Carlo Tree Search (MCTS) to simulate entire sequences of actions. We use a state-of-the-art search-based agent, MuZero [48], that constructs a learnable model of the environment dynamics, simulating transitions in this latent representation and leading to significant computational benefits. At every step, the enhanced model with its new components produces value [50] and reward estimates, which define an exploration strategy. Simulations into future sequences of actions are performed based on this strategy, helping the model to make decisions based on future outcomes, not yet experienced. Compared to a simpler PPO objective [49, 41], that in our experience did not lead to significant improvements, MCTS generates a series of simulations traversing the tree from a root node, generating more + +![](images/5d674a1311acd3c4b95c744697c9304c3b0c023a027839930ef5e2ce5410de8a.jpg) +Figure 4. The autoregressive model with its three main components. (1) A backbone image model (ResNet) that extracts features for each key point at different scales, along with a global image embedding. (2) A key point model embeds visual and location features of distinct key points. (3) An edge embedding model relates the current edge sequence with the respective key points. Each edge token (signalled with the tokens 'index-i') corresponds to an index specifying the respective key point. A pair of such tokens designates an edge as its two endpoints. At the end of (3) we obtain a new distribution over key points that leads to an incremental update to the graph, after sampling. + +stable value and reward estimates. MuZero requires three distinct parts (see also Fig. 5): + +1. A representation function $f$ creates a latent vector of the current state $\pmb{h}_t = f_\theta(\pmb{o}_t)$ , in our case the autoregressive model, shown in Fig. 4. Our current latent representation $\pmb{h}_t$ contains the graph's hidden state along with the key points' embeddings used to map actions to latent vectors. As key points remain the same throughout the episode, image-based features (Components (1) and (2) in Fig. 4) are only computed once. +2. A dynamics network $g$ , we use a simple LSTM [20], as commonly done, that predicts the effect of a new action by predicting the next hidden state and the expected reward: $(\hat{h}_t, \hat{r}_t) = g_\theta(\hat{h}_{t-1}, \alpha_t)$ . We can replace $\tilde{h}_{t-1}$ with the latent representation $h_{t-1}$ , or its previous computed approximation $\hat{h}_{t-1}$ for tree search of depth larger than 1. +3. A prediction network $\psi$ , that estimates the policy and the value for the current state $(\pmb{p}_{t+1}, v_t) = \psi_\theta(\tilde{\pmb{h}}_t)$ . We compute the policy via a pointer network as described in Section 3.1. Value estimates are produced by a simple multi-layer perceptron. + +The dynamics network guides the search and evaluates the expected reward of actions. For every newly generated edge, we also explicitly inform the network regarding the creation of new intersections and the expected relative change in the overall road surface generated via embeddings (see Fig. 5). By using the dynamics network, we bypass the expensive call to the decoder module during the search, and can instead approximate small modifications in the latent representation directly. For our experiments, the dynamics + +![](images/bacb4f43b159a22feb9ec2adcd9e94fabbebc9be883d27232656d909cdeecc40.jpg) +Figure 5. The autoregressive model generates a hidden state corresponding to the graph embedding. (a) When doing so, the edge decoder directly attends to the input key points' embeddings, augmented by position and type embeddings. (b) The prediction network uses the hidden state to produce value and policy predictions. A pointer network allows an intuitive scale of the action space by the number of key points. (c) The dynamics network simulates trajectories by estimating new hidden states and rewards. For newly generated edges, it takes as input the embeddings of the new key points, but also the degree of the two vertices involved and the length of the newly proposed generated edge. + +network requires up to 90 times less floating-point operations to simulate trajectories, compared to using the edge embeddings' decoder. Effectively, our method does not involve significantly more computation budget compared to the base autoregressive model. More details regarding the MuZero training and exploration are provided in Section 4 and in the appendix. + +# 3.3. Evaluation metrics + +We adopt the same evaluation metrics both as a comparison between different methods and to determine the reward for our agent, through Eq. 3. We use the relaxed versions of + +precision, recall, and intersection over union for pixel-level predictions Correctness/Completeness/Quality (CCQ) [66, 64]. As graph-theoretic metrics we use APLS [60] and additionally include new metrics introduced in [14] that compare Paths, Junctions and Sub-graphs of the graphs in question, producing respectively precision, recall and $f_{1}$ scores. More details can be found in the appendix. + +# 4. Experiments + +Implementation details. We resize images to $300 \times 300$ pixels, standardizing according to the training set statistics. For exploration, we initialize workers using Ray [33] that execute episodes in the environment. For training, we unroll the dynamics function for $t_d = 5$ steps and use priority weights for the episode according to the differences between predicted and target values. Our algorithm can be considered as an approximate on-policy TD( $\lambda$ ) [55] due to the relatively small replay buffer. We reanalyse older games [48] to provide fresher target estimates. Unvisited graph nodes are selected based on an upper confidence score, balancing exploration with exploitation, similar to [51]. We add exploration noise as Dirichlet noise and select actions based on a temperature-controlled sampling procedure, whose temperature is reduced during training. + +Given the limited high-quality available ground truth labels [52] and to accelerate training, we employ modifications introduced in EfficientZero [71]. We investigate adding supervision to the environment model and better initialize Q-value predictions similar to the implementation of Elf OpenGo [57]. We further scale values and rewards using an invertible transform inspired by [44]. Here, we predict support, as fully connected networks are biased towards learning low-frequency representations [21]. Selecting new actions involves generating simulations that can be done expeditiously given the small dimension of the latent space and the modest size of the dynamics network. Finally, to generate key points, we skeletonize segmentation masks provided by any baseline segmentation model, by thresholding the respective segmentation masks produced and applying RDP-simplification [17, 46]. Selecting an appropriate threshold and subdividing larger edges guarantees that the generated set $\mathcal{V}'$ adequately captures most of the ground truth road network, leaving the complexity of the problem for our model to handle. We will use the term ARM to denote the autoregressive model and Ours for the RL-tuned model. + +# 4.1. Synthetic dataset + +Initially, a simplified setting is chosen wherein the complete governance of both the nature and intensity of the difficulty inherent in the road-extraction task can be regulated. We generate a dataset of overhead satellite images of a syn + +![](images/d4914a2d2c86ee8ef4099f953c98ae4debab9d3d3bae666611cee750869bd331.jpg) +Figure 6. (Left) Examples of fragmented outputs from the LinkNet model under cases of significant occlusion and how our approach performs in these demanding circumstances. (Right) The performance gap between our method and the same baseline is wide, based on topological spatial graph metrics, for a wide range of difficulties in the images. More details and examples are given in the supplementary material. + +thetic town using CityEngine1. We randomly specify vegetation of varying height and width along the side walks of the generated streets, leading inadvertently to occlusions of varying difficulty. The simulated environment allows specifying pixel-perfect masks regarding both roads and trees occluding the road surface based on the provided camera parameters [23]. We defer more details regarding the generation process and dataset examples to the supplementary material. + +We compare our method by training on our dataset a LinkNet model [10], a popular segmentation model that has been widely used in the remote sensing community [25]. Even in this synthetic and thus less diverse scenario, the deficiency of segmentation models to rely mostly on local information, with no explicit ability for longer-range interactions, is evident. Fig. 6 illustrates examples of such oversegmented predictions and how our approach can improve on them. We also define a 'difficulty' attribute per synthetic satellite image, quantifying the occlusions as a percentage of the ground truth road mask covered. We observe a considerable absolute improvement in topological metric scores when training our model on this synthetic dataset, compared to the baseline, for varying image difficulty. + +# 4.2. Real datasets + +We assess our approach on the SpaceNet and DeepGlobe datasets. A single image is provided to our method, with a spatial graph being generated as the output. We use the same train-test splits as in [8] to promote reproducibility, while results are reported for the final combined graph on the original image scale. No pre-training on the synthetic + +
MethodCCQTLTSAPLS ↑Path-BasedJunction-BasedSub-graph-Based f1 ↑
corr. ↑comp. ↑qual. ↑corr. ↑2l+2s ↓pre. ↑rec. ↑f1 ↑pre. ↑rec. ↑f1 ↑
SpaceNetDeepRoadMapper [29]0.69430.68380.53860.41100.10120.51430.59580.64000.61710.62930.74430.68200.6783
Segmentation [28, 22]0.74930.70940.59690.41430.08280.54540.69090.68630.68850.71860.77100.74380.7117
LinkNet [10]0.81000.74490.64090.48940.07430.57430.67190.64600.65860.69850.78090.73740.7576
Orientation [8]0.80700.80010.68620.55940.08840.63150.71750.72800.72270.75520.75910.75710.7802
Sat2Graph [18]**0.69170.73510.57340.58020.11040.59510.59520.54160.56710.74740.59510.66260.7180
SPIN road mapper [5]0.78370.79880.66210.59220.10580.64220.72760.72650.72700.76210.78270.77220.7837
Ours0.81500.80920.69320.59700.07320.65870.73830.76130.74960.78450.78210.78330.7948
DeepGlobeLinkNet [10]0.80120.86760.73280.66400.08040.65250.68820.69200.69010.76750.74440.75580.7879
Orientation [8]0.82430.88570.75450.68660.10470.70120.69370.80820.74650.76240.79390.77780.8282
Ours*0.82230.89790.74940.72420.07430.74000.71500.82740.76710.79120.82830.80930.8391
+ +* We do not fine-tune our model on the DeepGlobe dataset but instead refine predictions standardizing according to train dataset statistics. +** The authors provided predictions corresponding only to a center crop of the original SpaceNet dataset images. Also, note that the test set is different from the one reported on the rest of the methods, see also the appendix. Blue: best score, Green: second best score, Gray: results reported in different test set + +Table 1. Quantitative results for the SpaceNet and DeepGlobe datasets. + +
DeepRoadMapper [29]Segmentation [22]Orientation [8]OursGround TruthSatellite Image
+ +Table 3. APLS metric and perplexity (bits of information per edge) results for the SpaceNet dataset with provided key points that adequately capture the ground truth graph. Autoregressive order is defined in Section 3, while random order entails random permutation between edges and the order of key points within edges. To calculate perplexity for our method we use the initial predicted policy distribution, without any additional search. More details on baselines and general approach are presented in the appendix. + +Table 2. Qualitative results of improved connectivity. We recommend zooming in for more details. + +
Method MetricRandomClsGCNARMOurs
APLS0.0080.4300.5940.8940.928
Bits per edge: Autoregressive order8.743--0.5284.321
Bits per edge: Random order8.743--28.744.432
+ +dataset takes place. + +# 4.2.1 Comparison to Baselines + +We initially train the ARM model on ground-truth graph information by using a set of key points $\mathcal{V}' = \mathcal{V}$ . Even in this scenario, RL tuning increases the semantic quality of the extracted graphs as seen in Table 3. In cases where the set $\mathcal{V}'$ is imperfect, and for reasons elaborated in Section 3, newly proposed edges may be only partially correct. Under + +such circumstances, supervised training is infeasible, hence we rely on RL to produce the graph that leads to the maximum cumulative reward, i.e. our selected evaluation metrics. We conduct comparative analysis against the following approaches; we explore powerful CNN architectures, by training a Segmentation model with a ResNet backbone. We evaluate DeepRoadMapper [29], a model that refines previous segmentation by adding connections along possible identified paths. As done by [8] we notice that in complex scenarios, the effect of this post-processing step is not always positive. We also evaluate against LinkNet [10], and Orientation [8], which is trained to predict simultaneously road surfaces and orientation, and the relevant baselines [18, 5]. + +Quantitative results in Table 1 and visual inspection in Table 2, affirm that the global context and the gradual generation incite a better understanding of the scene, leading to consistently outperforming topological metric results compared to the baselines. We remark that our predictions are more topologically consistent with fewer shortcomings, such as double roads, fragmented roads, and overconnections. This is further supplemented by comparing the statistics of the predicted spatial graphs in Fig. 7. We further + +![](images/37842d88c031a521df9c6fe696804a521702307cf1bb47ca41bcfa99c313e436.jpg) +Figure 7. (Left) Comparison of generated graph statistics, following the same post-processing, averaged across regions of $400 \times 400$ meters in ground distance. Orientation refers to the method of [8]. (Right) The estimated Pareto front achieved through the evaluation of various runs, where a different number of MCTS simulations is being executed at each state. obj refers to an average of the APLS, Path-based f1, Junction-based f1 and Sub-graph-based f1 metrics. + +![](images/7783eeeec9752c14d156a15f5840c3d2730140225ee8e446bc75b44c33302a6f.jpg) + +![](images/f97b8cb663405ceba97add71edc6f0c7a85ea2b40a2d193c289022895b126dba.jpg) + +![](images/aa7767f3b065226d13532d14cfc3f77db60de60704f7197aa1cacba5a42a6e4e.jpg) + +![](images/59f6217c578e90777964331a4c268c7a5a5f65a975e2a5604c1ea11fd5b1f4f8.jpg) + +showcase the transferability of our model by employing it with no fine-tuning (apart from dataset-specific image normalization) on the DeepGlobe dataset. We can refine previous predictions by adding missing edges, leading to more accurate spatial graph predictions, as shown in Table 1. Our conjecture that road structures and their geometric features exhibit a high degree of recurrence across various locations and geographic regions worldwide is thus confirmed. + +# 4.2.2 Ablation study + +We experimented attending to image features for the two transformer modules by extracting per-patch visual features from the conditioning image $H^{\mathrm{img}} = [h_1^{\mathrm{img}}, h_2^{\mathrm{img}}, \ldots]$ , as done in the Vision Transformer [16]. This did not lead to significant improvements, which we attribute to over-fitting. In Table. 4 we highlight the relative importance of some additional components for the final predictions. As efficiency is also of particular importance to us, we further visualize the effect of varying the simulation depth of the dynamics network during training (Fig. 7 (right)). Surprisingly perhaps, our method performs consistently even with a limited number of simulations. + +In the appendix, we provide incremental results for the task of predicting road networks based on an optimal set of key points and insights concerning interpretability and further comparison to baselines based on the varying difficulty of the predicted underlying road networks. We also give more information regarding the generation of the synthetic dataset and the model architecture. Finally, we provide more implementation decisions, including details on exactly how key points and generated and how individual patch-level predictions are fused together. It is important to emphasize that our proposed method can operate effectively even when working with partially initialized predictions, making it a practical refinement approach that can be applied to existing baselines. By initializing our model based on the ARM model, we can achieve a rapid fine-tuning phase. Additionally, by utilizing the learned environment model, which avoids the need for expensive calls to the edge embedding model at each simulation step in MCTS, we can train the model even using a single GPU. + +
ModelAPLSP-f1J-f1S-f1
Ours0.65870.74960.78330.7948
- autoregressive pre-training-15.3%-13.7%-14.1%-13.3%
- visual features for key-points-13.4%-12.7%-12.1%-12.3%
- tree-search during evaluation-2.1%-1.4%-1.7%-1.1%
+ cross attend to image features+0.2%-0.4%-0.7%-0.3%
+ +P: Path-based, J: Junction-based, S: Sub-graph-based + +Table 4. Ablations study on SpaceNet dataset. + +# 5. Conclusions + +We presented a reinforcement learning framework for tuning autoregressive tasks for the task of generating a graph as a variable-length edge sequence, where a structured-aware decoder selects new edges by simulating action sequences into the future. Importantly, this allows the model to better capture the geometry of the targeted objects. One advantage of the proposed method is that the reward function is based on (non-continuous) metrics that are directly connected to the application in question. Our approach does not require significantly more computational resources compared to state-of-the-art supervised approaches, and in addition, it can be used to refine predictions from another given model. We also remark that the direct prediction of a graph enables the concurrent prediction of meta-information about the edges, including, for instance, the type of road (e.g. highway, primary or secondary street, biking lane). + +Our approach opens the door to several directions for future work. For example, we have assumed that a pre-defined model gives the location of key points, but one could instead augment the action space to propose new key points' locations. Other promising directions include the direct prediction of input-dependent graph primitives, e.g. T-junctions or roundabouts. Finally, we emphasize that our approach is suitable for a wide variety of applications where autoregressive models are typically used, which we intend to look into in the future. Such applications include among others, Scene Graph Generation [67, 70] and Visual reasoning/Factual Visual Question Answering [11, 35]. + +# 6. Reproducibility Statement + +We have taken multiple steps to ensure the reproducibility of the experiments. We refer the reader to the appendix for a complete description of the training protocol. We have also released the code as part of the supplementary material. + +# References + +[1] Samira Abnar and Willem Zuidema. Quantifying attention flow in transformers. arXiv preprint arXiv:2005.00928, 2020. +[2] David Acuna, Amlan Kar, and Sanja Fidler. Devil is in the edges: Learning semantic boundaries from noisy annotations. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11075-11083, 2019. +[3] Nicolas Audebert, Bertrand Le Saux, and Sébastien Lefèvre. Joint learning from earth observation and openstreetmap data to get faster better semantic maps. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 67-75, 2017. +[4] Yuntao Bai, Andy Jones, Kamal Ndousse, Amanda Askell, Anna Chen, Nova DasSarma, Dawn Drain, Stanislav Fort, Deep Ganguli, Tom Henighan, et al. Training a helpful and harmless assistant with reinforcement learning from human feedback. arXiv preprint arXiv:2204.05862, 2022. +[5] Wele Gedara Chaminda Bandara, Jeya Maria Jose Valanarasu, and Vishal M Patel. Spin road mapper: Extracting roads from aerial images via spatial and interaction space graph reasoning for autonomous driving. In 2022 International Conference on Robotics and Automation (ICRA), pages 343-350. IEEE, 2022. +[6] Meir Barzohar and David B Cooper. Automatic finding of main roads in aerial images by using geometric-stochastic models and estimation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 18(7):707-721, 1996. +[7] Favyen Bastani, Songtao He, Sofiane Abbar, Mohammad Al-izadeh, Hari Balakrishnan, Sanjay Chawla, Sam Madden, and David DeWitt. Roadtracer: Automatic extraction of road networks from aerial images. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4720–4728, 2018. +[8] Anil Batra, Suriya Singh, Guan Pang, Saikat Basu, CV Jawahar, and Manohar Paluri. Improved road connectivity by joint learning of orientation and segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10385-10393, 2019. +[9] Cameron B Browne, Edward Powley, Daniel Whitehouse, Simon M Lucas, Peter I Cowling, Philipp Rohlfshagen, Stephen Tavener, Diego Perez, Spyridon Samothrakis, and Simon Colton. A survey of monte carlo tree search methods. IEEE Transactions on Computational Intelligence and AI in games, 4(1):1-43, 2012. +[10] Abhishek Chaurasia and Eugenio Culurciello. Linknet: Exploiting encoder representations for efficient semantic segmentation. In 2017 IEEE Visual Communications and Image Processing (VCIP), pages 1-4. IEEE, 2017. + +[11] Xinlei Chen, Li-Jia Li, Li Fei-Fei, and Abhinav Gupta. Iterative visual reasoning beyond convolutions. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 7239-7248, 2018. +[12] Benjamin E Childs, James H Brodeur, and Levente Kocsis. Transpositions and move groups in monte carlo tree search. In 2008 IEEE Symposium On Computational Intelligence and Games, pages 389-395. IEEE, 2008. +[13] Hang Chu, Daiqing Li, David Acuna, Amlan Kar, Maria Shugrina, Xinkai Wei, Ming-Yu Liu, Antonio Torralba, and Sanja Fidler. Neural turtle graphics for modeling city road layouts. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4522-4530, 2019. +[14] Leonardo Citraro, Mateusz Kozinski, and Pascal Fua. Towards reliable evaluation of algorithms for road network reconstruction from aerial images. In European Conference on Computer Vision, pages 703-719. Springer, 2020. +[15] Ilke Demir, Krzysztof Koperski, David Lindenbaum, Guan Pang, Jing Huang, Saikat Basu, Forest Hughes, Devis Tuia, and Ramesh Raskar. Deep globe 2018: A challenge to parse the earth through satellite images. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 172-181, 2018. +[16] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020. +[17] David H Douglas and Thomas K Peucker. Algorithms for the reduction of the number of points required to represent a digitized line or its caricature. Cartographica: the international journal for geographic information and geovisualization, 10(2):112-122, 1973. +[18] Songtao He, Favyen Bastani, Satvat Jagwani, Mohammad Alizadeh, Hari Balakrishnan, Sanjay Chawla, Mohamed M Elshrif, Samuel Madden, and Mohammad Amin Sadeghi. Sat2graph: Road graph extraction through graph-tensor encoding. In European Conference on Computer Vision, pages 51-67. Springer, 2020. +[19] Stefan Hinz and Albert Baumgartner. Automatic extraction of urban road networks from multi-view aerial imagery. IS-PRS journal of photogrammetry and remote sensing, 58(1-2):83-98, 2003. +[20] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 9(8):1735-1780, 1997. +[21] Arthur Jacot, Franck Gabriel, and Clément Hongler. Neural tangent kernel: Convergence and generalization in neural networks. arXiv preprint arXiv:1806.07572, 2018. +[22] Pascal Kaiser, Jan Dirk Wegner, Aurélien Lucchi, Martin Jaggi, Thomas Hofmann, and Konrad Schindler. Learning aerial image segmentation from online maps. IEEE Transactions on Geoscience and Remote Sensing, 55(11):6054-6068, 2017. +[23] Fanjie Kong, Bohao Huang, Kyle Bradbury, and Jordan Malof. The synthinel-1 dataset: a collection of high resolution synthetic overhead imagery for building segmentation. + +In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1814-1823, 2020. +[24] Ngan Le, Vidhiwar Singh Rathour, Kashu Yamazaki, Khoa Luu, and Marios Savvides. Deep reinforcement learning in computer vision: a comprehensive survey. Artificial Intelligence Review, pages 1-87, 2021. +[25] Yuxia Li, Bo Peng, Lei He, Kunlong Fan, and Ling Tong. Road segmentation of unmanned aerial vehicle remote sensing images using adversarial network with multiscale context aggregation. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 12(7):2279-2287, 2019. +[26] Zuoyue Li, Jan Dirk Wegner, and Aurélien Lucchi. Topological map extraction from overhead images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 1715-1724, 2019. +[27] Renbao Lian, Weixing Wang, Nadir Mustafa, and Liqin Huang. Road extraction methods in high-resolution remote sensing images: A comprehensive review. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 13:5489-5507, 2020. +[28] Jonathan Long, Evan Shelhamer, and Trevor Darrell. Fully convolutional networks for semantic segmentation. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3431-3440, 2015. +[29] Gellert Mattyus, Wenjie Luo, and Raquel Urtasun. Deeproadmapper: Extracting road topology from aerial images. In Proceedings of the IEEE International Conference on Computer Vision, pages 3438-3446, 2017. +[30] Gellert Mattyus and Raquel Urtasun. Matching adversarial networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 8024-8032, 2018. +[31] Gellert Mattyus, Shenlong Wang, Sanja Fidler, and Raquel Urtasun. Enhancing road maps by parsing aerial images around the world. In Proceedings of the IEEE international conference on computer vision, pages 1689-1697, 2015. +[32] Javier A Montoya-Zegarra, Jan D Wegner, L'ubor Ladický, and Konrad Schindler. On the evaluation of higher-order cliques for road network extraction. In 2015 Joint Urban Remote Sensing Event (JURSE), pages 1-4. IEEE, 2015. +[33] Philipp Moritz, Robert Nishihara, Stephanie Wang, Alexey Tumanov, Richard Liaw, Eric Liang, William Paul, Michael I Jordan, and Ion Stoica. Ray: A distributed framework for emerging ai applications. corr abs/1712.05889 (2017). arXiv preprint arXiv:1712.05889, 2017. +[34] Agata Mosinska, Pablo Marquez-Neila, Mateusz Kozinski, and Pascal Fua. Beyond the pixel-wise loss for topology-aware delineation. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3136–3145, 2018. +[35] Medhini Narasimhan, Svetlana Lazebnik, and Alexander Schwing. Out of the box: Reasoning with graph convolution nets for factual visual question answering. Advances in neural information processing systems, 31, 2018. +[36] Charlie Nash, Yaroslav Ganin, SM Ali Eslami, and Peter Battaglia. *Polygon: An autoregressive generative model of + +3d meshes. In International Conference on Machine Learning, pages 7220-7229. PMLR, 2020. +[37] Alejandro Newell, Kaiyu Yang, and Jia Deng. Stacked hourglass networks for human pose estimation. In European conference on computer vision, pages 483-499. Springer, 2016. +[38] Joachim Niemeyer, Jan Dirk Wegner, Clément Mallet, Franz Rottensteiner, and Uwe Soergel. Conditional random fields for urban scene classification with full waveform lidar data. In ISPRS Conference on Photogrammetric Image Analysis, pages 233-244. Springer, 2011. +[39] Aäron van den Oord, Nal Kalchbrenner, Oriol Vinyals, Lasse Espeholt, Alex Graves, and Koray Kavukcuoglu. Conditional image generation with pixelCNN decoders. In Proceedings of the 30th International Conference on Neural Information Processing Systems, pages 4797-4805, 2016. +[40] OpenStreetMap contributors. Planet dump retrieved from https://planet.osm.org . https://www.openstreetmap.org, 2017. +[41] Long Ouyang, Jeff Wu, Xu Jiang, Diogo Almeida, Carroll L Wainwright, Pamela Mishkin, Chong Zhang, Sandhini Agarwal, Katarina Slama, Alex Ray, et al. Training language models to follow instructions with human feedback. arXiv preprint arXiv:2203.02155, 2022. +[42] Wamiq Para, Paul Guerrero, Tom Kelly, Leonidas J Guibas, and Peter Wonka. Generative layout modeling using constraint graphs. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6690-6700, 2021. +[43] Wamiq Reyaz Para, Shariq Farooq Bhat, Paul Guerrero, Tom Kelly, Niloy Mitra, Leonidas Guibas, and Peter Wonka. Sketchgen: Generating constrained cad sketches. arXiv preprint arXiv:2106.02711, 2021. +[44] Tobias Pohlen, Bilal Piot, Todd Hester, Mohammad Gheshlaghi Azar, Dan Horgan, David Budden, Gabriel BarthMaron, Hado Van Hasselt, John Quan, Mel Večerík, et al. Observe and look further: Achieving consistent performance on atari. arXiv preprint arXiv:1805.11593, 2018. +[45] Pengda Qin, Weiran Xu, and William Yang Wang. Robust distant supervision relation extraction via deep reinforcement learning. arXiv preprint arXiv:1805.09927, 2018. +[46] Urs Ramer. An iterative procedure for the polygonal approximation of plane curves. Computer graphics and image processing, 1(3):244-256, 1972. +[47] Abdallah Saffidine, Tristan Cazenave, and Jean Méhat. Ucd: Upper confidence bound for rooted directed acyclic graphs. Knowledge-Based Systems, 34:26-33, 2012. +[48] Julian Schrittwieser, Ioannis Antonoglou, Thomas Hubert, Karen Simonyan, Laurent Sifre, Simon Schmitt, Arthur Guez, Edward Lockhart, Demis Hassabis, Thore Graepel, et al. Mastering atari, go, chess and shogi by planning with a learned model. Nature, 588(7839):604-609, 2020. +[49] John Schulman, Filip Wolski, Prafulla Dhariwal, Alec Radford, and Oleg Klimov. Proximal policy optimization algorithms. arXiv preprint arXiv:1707.06347, 2017. +[50] David Silver, Hado Hasselt, Matteo Hessel, Tom Schaul, Arthur Guez, Tim Harley, Gabriel Dulac-Arnold, David Reichert, Neil Rabinowitz, Andre Barreto, et al. The predictron: + +End-to-end learning and planning. In International Conference on Machine Learning, pages 3191-3199. PMLR, 2017. +[51] David Silver, Thomas Hubert, Julian Schrittwieser, Ioannis Antonoglou, Matthew Lai, Arthur Guez, Marc Lanctot, Laurent Sifre, Dharshan Kumaran, Thore Graepel, et al. A general reinforcement learning algorithm that masters chess, shogi, and go through self-play. Science, 362(6419):1140-1144, 2018. +[52] Suriya Singh, Anil Batra, Guan Pang, Lorenzo Torresani, Saikat Basu, Manohar Paluri, and CV Jawahar. Self-supervised feature learning for semantic segmentation of overhead imagery. In BMVC, volume 1, page 4, 2018. +[53] Edward J Smith, Scott Fujimoto, Adriana Romero, and David Meger. Geometrics: Exploiting geometric structure for graph-encoded objects. arXiv preprint arXiv:1901.11461, 2019. +[54] André Susano Pinto, Alexander Kolesnikov, Yuge Shi, Lucas Beyer, and Xiaohua Zhai. Tuning computer vision models with task rewards. arXiv e-prints, pages arXiv-2302, 2023. +[55] Richard S Sutton and Andrew G Barto. Reinforcement learning: An introduction. MIT press, 2018. +[56] Yong-Qiang Tan, Shang-Hua Gao, Xuan-Yi Li, Ming-Ming Cheng, and Bo Ren. Vecroad: Point-based iterative graph exploration for road graphs extraction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8910-8918, 2020. +[57] Yuandong Tian, Jerry Ma, Qucheng Gong, Shubho Sengupta, Zhuoyuan Chen, James Pinkerton, and Larry Zitnick. Elf opengo: An analysis and open reimplementation of alphahzero. In International Conference on Machine Learning, pages 6244-6253. PMLR, 2019. +[58] Benigno Uria, Iain Murray, and Hugo Larochelle. A deep and tractable density estimator. In International Conference on Machine Learning, pages 467-475. PMLR, 2014. +[59] Aïron van den Oord, Sander Dieleman, Heiga Zen, Karen Simonyan, Oriol Vinyals, Alex Graves, Nal Kalchbrenner, Andrew Senior, and Koray Kavukcuoglu. Wavenet: A generative model for raw audio. In 9th ISCA Speech Synthesis Workshop, pages 125-125, 2016. +[60] Adam Van Etten, Dave Lindenbaum, and Todd M Bacastow. Spacenet: A remote sensing dataset and challenge series. arXiv preprint arXiv:1807.01232, 2018. +[61] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Advances in neural information processing systems, pages 5998-6008, 2017. +[62] Oriol Vinyals, Meire Fortunato, and Navdeep Jaitly. Pointer networks. arXiv preprint arXiv:1506.03134, 2015. +[63] Nanyang Wang, Yinda Zhang, Zhuwen Li, Yanwei Fu, Wei Liu, and Yu-Gang Jiang. Pixel2mesh: Generating 3d mesh models from single rgb images. In Proceedings of the European Conference on Computer Vision (ECCV), pages 52-67, 2018. +[64] Shenlong Wang, Min Bai, Gellert Mattyus, Hang Chu, Wenjie Luo, Bin Yang, Justin Liang, Joel Cheverie, Sanja Fidler, and Raquel Urtasun. Toronto: Seeing the world with a million eyes. arXiv preprint arXiv:1612.00423, 2016. + +[65] Jan D Wegner, Javier A Montoya-Zegarra, and Konrad Schindler. A higher-order crf model for road network extraction. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1698-1705, 2013. +[66] Christian Wiedemann, Christian Heipke, Helmut Mayer, and Olivier Jamet. Empirical evaluation of automatically extracted road axes. Empirical evaluation techniques in computer vision, 12:172-187, 1998. +[67] Danfei Xu, Yuke Zhu, Christopher B Choy, and Li Fei-Fei. Scene graph generation by iterative message passing. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5410-5419, 2017. +[68] Jingtao Xu, Yali Li, and Shengjin Wang. Adazoom: Adaptive zoom network for multi-scale object detection in large scenes. arXiv preprint arXiv:2106.10409, 2021. +[69] Zhenhua Xu, Yuxuan Liu, Lu Gan, Yuxiang Sun, Xinyu Wu, Ming Liu, and Lujia Wang. Rngdet: Road network graph detection by transformer in aerial images. IEEE Transactions on Geoscience and Remote Sensing, 60:1-12, 2022. +[70] Jianwei Yang, Jiasen Lu, Stefan Lee, Dhruv Batra, and Devi Parikh. Graph r-cnn for scene graph generation. In Proceedings of the European conference on computer vision (ECCV), pages 670-685, 2018. +[71] Weirui Ye, Shaohuai Liu, Thanard Kurutach, Pieter Abbeel, and Yang Gao. Mastering atari games with limited data. arXiv preprint arXiv:2111.00210, 2021. \ No newline at end of file diff --git a/2023/Mastering Spatial Graph Prediction of Road Networks/images.zip b/2023/Mastering Spatial Graph Prediction of Road Networks/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..b7fb70e7895b9b65285c32865117077f365493f8 --- /dev/null +++ b/2023/Mastering Spatial Graph Prediction of Road Networks/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:3d2109ddd42dc5a11d6e2db03cec5353cbeb9a1c2b2332bcec792797d593f518 +size 714940 diff --git a/2023/Mastering Spatial Graph Prediction of Road Networks/layout.json b/2023/Mastering Spatial Graph Prediction of Road Networks/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..6b6f02995b1a2fd3fa4acfc7c36870a0992846a3 --- /dev/null +++ b/2023/Mastering Spatial Graph Prediction of Road Networks/layout.json @@ -0,0 +1,7895 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 127, + 103, + 467, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 127, + 103, + 467, + 121 + ], + "spans": [ + { + "bbox": [ + 127, + 103, + 467, + 121 + ], + "type": "text", + "content": "Mastering Spatial Graph Prediction of Road Networks" + } + ] + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 83, + 142, + 511, + 331 + ], + "blocks": [ + { + "bbox": [ + 83, + 142, + 511, + 331 + ], + "lines": [ + { + "bbox": [ + 83, + 142, + 511, + 331 + ], + "spans": [ + { + "bbox": [ + 83, + 142, + 511, + 331 + ], + "type": "image", + "image_path": "39e1605452bce5ce8cf84949b7a25e8c56a8e5a386b9bed9b83b78f260088d1b.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 334, + 547, + 357 + ], + "lines": [ + { + "bbox": [ + 46, + 334, + 547, + 357 + ], + "spans": [ + { + "bbox": [ + 46, + 334, + 547, + 357 + ], + "type": "text", + "content": "Figure 1. Our agent interacts with the currently generated spatial graph by proposing new edges to be added. A tree-based search produces a sequence of actions that maximizes a reward function based on complex geometrics priors." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 373, + 192, + 387 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 373, + 192, + 387 + ], + "spans": [ + { + "bbox": [ + 143, + 373, + 192, + 387 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 399, + 290, + 639 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 399, + 290, + 639 + ], + "spans": [ + { + "bbox": [ + 46, + 399, + 290, + 639 + ], + "type": "text", + "content": "Accurately predicting road networks from satellite images requires a global understanding of the network topology. We propose to capture such high-level information by introducing a graph-based framework that given a partially generated graph, sequentially adds new edges. To deal with misalignment between the model predictions and the intended purpose, and to optimize over complex, non-continuous metrics of interest, we adopt a reinforcement learning (RL) approach that nominates modifications that maximize a cumulative reward. As opposed to standard supervised techniques that tend to be more restricted to commonly used surrogate losses, our framework yields more power and flexibility to encode problem-dependent knowledge. Empirical results on several benchmark datasets demonstrate enhanced performance and increased high-level reasoning about the graph topology when using a tree-based search. We further demonstrate the superiority of our approach in handling examples with substantial occlusion and additionally provide evidence that our predictions better match the statistical properties of the ground dataset." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 651, + 128, + 662 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 651, + 128, + 662 + ], + "spans": [ + { + "bbox": [ + 47, + 651, + 128, + 662 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 670, + 288, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 670, + 288, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 670, + 288, + 696 + ], + "type": "text", + "content": "Road layout modelling from satellite images constitutes an important task of remote sensing, with applications in" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 374, + 546, + 578 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 374, + 546, + 578 + ], + "spans": [ + { + "bbox": [ + 306, + 374, + 546, + 578 + ], + "type": "text", + "content": "everyday life, such as traffic flow prediction and navigation. The vast amounts of data available from the commercialization of geospatial data, in addition to the need for accurately establishing the connectivity of roads in remote areas, have led to an increased interest in the precise representation of existing road networks. By nature, these applications require structured data types that provide efficient representations to encode geometry, in this case, graphs, a de facto choice in domains such as computer graphics, virtual reality, gaming, and the film industry. These structured-graph representations are also commonly used to label recent road network datasets [60] and map repositories [40]. When dealing with complex predicted structures, however, how well the model optimizes a surrogate objective is not always the best indication of how well the model's predictions are aligned with the required task risk, i.e. the targeted final utilization." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "type": "text", + "content": "Problems of this nature have been recently extensively studied in the regime of natural language processing, where the misalignment between training objectives for tasks such as machine translation and summarization has garnered considerable attention among the academic community, who have devoted significant efforts to its analysis and elucidation. A popular emerging technique is to first learn to imitate some example outputs and then fix any misalignment issues by using reinforcement learning to adjust the predictions based on a reward function. The reward usually comes in the form of external human evaluation [41, 4]." + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 38 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 38 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 38 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 702, + 227, + 714 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 227, + 714 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 227, + 714 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 58, + 702, + 227, + 714 + ], + "type": "text", + "content": "Correspondence sotirios.anagnostidis@inf.ethz.ch." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 295, + 750, + 316, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 750, + 316, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 750, + 316, + 758 + ], + "type": "text", + "content": "5408" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 62, + 72, + 175, + 171 + ], + "blocks": [ + { + "bbox": [ + 62, + 72, + 175, + 171 + ], + "lines": [ + { + "bbox": [ + 62, + 72, + 175, + 171 + ], + "spans": [ + { + "bbox": [ + 62, + 72, + 175, + 171 + ], + "type": "image", + "image_path": "289d74b5d8a6c6159644d8abbf0c30870bb8988556e3286346230df1ae30e3c4.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 173, + 547, + 219 + ], + "lines": [ + { + "bbox": [ + 46, + 173, + 547, + 219 + ], + "spans": [ + { + "bbox": [ + 46, + 173, + 547, + 219 + ], + "type": "text", + "content": "Figure 2. Typical road network features (SpaceNet dataset). From left to right: (a) the distribution of angles between road segments leading to the same intersection is biased towards 0 and 90 degrees, i.e. parallel or perpendicular roads. The same also holds (b) for angles between random road pieces within a ground distance of 400 meters. (c) Most road vertices belong to a single road piece, with a degree of 2. (d) The average number of intersections for areas of " + }, + { + "bbox": [ + 46, + 173, + 547, + 219 + ], + "type": "inline_equation", + "content": "400 \\times 400" + }, + { + "bbox": [ + 46, + 173, + 547, + 219 + ], + "type": "text", + "content": " meters by ground distance." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 181, + 72, + 294, + 171 + ], + "blocks": [ + { + "bbox": [ + 181, + 72, + 294, + 171 + ], + "lines": [ + { + "bbox": [ + 181, + 72, + 294, + 171 + ], + "spans": [ + { + "bbox": [ + 181, + 72, + 294, + 171 + ], + "type": "image", + "image_path": "fac45254ed5c48ba27e03a969eeb3008f80a5492ff823b3b086b98f006c1060e.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 301, + 72, + 411, + 171 + ], + "blocks": [ + { + "bbox": [ + 301, + 72, + 411, + 171 + ], + "lines": [ + { + "bbox": [ + 301, + 72, + 411, + 171 + ], + "spans": [ + { + "bbox": [ + 301, + 72, + 411, + 171 + ], + "type": "image", + "image_path": "aa09bbcd1294069573c2a851e307fe6f114f5107efd8469ab08fd1ca396d7aa4.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 417, + 72, + 529, + 171 + ], + "blocks": [ + { + "bbox": [ + 417, + 72, + 529, + 171 + ], + "lines": [ + { + "bbox": [ + 417, + 72, + 529, + 171 + ], + "spans": [ + { + "bbox": [ + 417, + 72, + 529, + 171 + ], + "type": "image", + "image_path": "3ea6de973e7faf2eb4f3627c7a3e60158c58eadb5ce6bd0b7f6681e886e91b41.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 228, + 289, + 623 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 228, + 289, + 623 + ], + "spans": [ + { + "bbox": [ + 47, + 228, + 289, + 623 + ], + "type": "text", + "content": "In this work we manifest how RL fine-tuning can greatly benefit and boost performance when producing intricate geometric predictions. For the task of road layout detection, existing methods, in contrast, mostly rely on pixel-based segmentation models that are trained on masks produced by rasterizing ground truth graphs. Performing pixel-wise segmentation, though, ignores structural features and geometric constraints inherent to the problem. As a result, minimum differences in the pixel-level output domain can have significant consequences in the proposed graph, in terms of connectivity and path distances, as manifested by the often fragmented outputs obtained after running inference on these models. In order to address these significant drawbacks, we propose a new paradigm where we (i) directly generate outputs as spatial graphs and (ii) formalize the problem as a game where we sequentially construct the output by adding edges between key points. These key points can in principle come from any off-the-shelf detector that identifies road pieces with sufficient accuracy. Our generation process avoids having to resort to cumbersome post-processing steps [8, 32] or optimize some surrogate objectives [30, 34] whose relation to the desired qualities of the final prediction can be disputed. Concurrently, the sequential decision-making strategy we propose enables us to focus interactively on different parts of the image, introducing the notion of a current state and producing reward estimates for a succession of actions. In essence, our method can be considered as a generalization of previous refinement techniques [8, 26] with three major advantages: (i) removal of the requirement for greedy decoding, (ii) ability to attend globally to the current prediction and selectively target parts of the image, and (iii) capacity to train based on demanding task-specific metrics." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 59, + 624, + 269, + 636 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 624, + 269, + 636 + ], + "spans": [ + { + "bbox": [ + 59, + 624, + 269, + 636 + ], + "type": "text", + "content": "More precisely, our contributions are the following:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 58, + 647, + 288, + 714 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 58, + 647, + 287, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 647, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 58, + 647, + 287, + 696 + ], + "type": "text", + "content": "- We propose a novel generic strategy for tuning autoregressive models that removes the requirement of decoding according to a pre-defined order and refines initial sampling probabilities via a tree search." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 58, + 701, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 701, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 58, + 701, + 288, + 714 + ], + "type": "text", + "content": "- We create a synthetic benchmark dataset of pixel-level" + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 324, + 228, + 545, + 277 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 324, + 228, + 545, + 277 + ], + "spans": [ + { + "bbox": [ + 324, + 228, + 545, + 277 + ], + "type": "text", + "content": "accurate labels of overhead satellite images for the task of road network extraction. This gives us the ability to simulate complex scenarios with occluded regions, allowing us to demonstrate improved robustness." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 317, + 282, + 547, + 319 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 282, + 547, + 319 + ], + "spans": [ + { + "bbox": [ + 317, + 282, + 547, + 319 + ], + "type": "text", + "content": "- We confirm the wide applicability of our approach by improving the performance of existing methods on the popular SpaceNet and DeepGlobe datasets." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 332, + 390, + 345 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 332, + 390, + 345 + ], + "spans": [ + { + "bbox": [ + 306, + 332, + 390, + 345 + ], + "type": "text", + "content": "2. Related work" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 354, + 545, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 354, + 545, + 640 + ], + "spans": [ + { + "bbox": [ + 304, + 354, + 545, + 640 + ], + "type": "text", + "content": "Initial attempts to extract road networks mainly revolved around handcrafted features and stochastic geometric models of roads [6]. Road layouts have specific characteristics regarding radiometry and topology e.g. particular junction distribution, certain general orientation, and curvature (see Fig. 2), that enable their detection even in cases with significant occlusion and uncertainty [19]. Modern approaches mostly formulate the road extraction task as a segmentation prediction task [27, 31, 3] by applying models such as Hourglass [37] or LinkNet [10]. This interpretation has significant drawbacks when evaluated against structural losses because of discontinuities in the predicted masks. Such shortcomings have been addressed by applying some additional post-processing steps, such as high-order conditional random fields [38, 65] or by training additional models that refine these initial predictions [29, 8]. Other common techniques include the optimization of an ensemble of losses. [13] rely on a directional loss and use non-maximal suppression as a thinning layer, while [8] calculate orientations of road segments. Although such auxiliary losses somewhat improve the output consistency, the fundamental issue of producing predictions in the pixel space persists. It remains impossible to overcome naturally occurring road structures, e.g. crossings of roads in different elevations, see Fig. 3." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 642, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 547, + 714 + ], + "type": "text", + "content": "Previous failure cases have led to more intuitive conceptualizations of the task. Roadtracer [7], iteratively builds a road network, similar to a depth-first search approach, while [13] learn a generative model for road layouts and then apply it as a prior on top of a segmentation prediction mask. Proposed graph-based approaches encode the road" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "text", + "content": "5409" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 86, + 71, + 509, + 178 + ], + "blocks": [ + { + "bbox": [ + 86, + 71, + 509, + 178 + ], + "lines": [ + { + "bbox": [ + 86, + 71, + 509, + 178 + ], + "spans": [ + { + "bbox": [ + 86, + 71, + 509, + 178 + ], + "type": "image", + "image_path": "ae7401aa94dbf125c2a87995e1e91ac77a5055cc773f910726b66a16bdfa70c5.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 182, + 547, + 216 + ], + "lines": [ + { + "bbox": [ + 46, + 182, + 547, + 216 + ], + "spans": [ + { + "bbox": [ + 46, + 182, + 547, + 216 + ], + "type": "text", + "content": "Figure 3. (Left) Typical segmentation-based methods generate an output graph by thresholding a segmentation mask, which can however often lead to fragmented outputs. Predicting segmentation masks also makes it impossible (right) to capture complex road interactions, such as overlapping roads at different elevations." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 227, + 289, + 430 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 227, + 289, + 430 + ], + "spans": [ + { + "bbox": [ + 46, + 227, + 289, + 430 + ], + "type": "text", + "content": "network directly as a graph, but either operate based on a constrained step-size [56] to generate new vertices or operate on a single step [18, 5], involving use-defined thresholding to post-process the final predictions. Most similar to our work, [26] predict locations of key points and define a specific order traversing them, as also done in [69]. Such autoregressive models have been recently successfully applied with the use of transformers [61] in a range of applications [36, 42, 43, 69] to model constraints between elements, where their supervised training explicitly requires tokens to be processed in a specific order. This specific order combined with the fact that only a surrogate training objective is used, introduces limitations, discussed further in the next section. In order to eliminate this order requirement and to optimize based on the desired metric, while attending globally to the currently generated graph, we propose to use RL as a suitable technique to tune these models." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 430, + 289, + 538 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 430, + 289, + 538 + ], + "spans": [ + { + "bbox": [ + 46, + 430, + 289, + 538 + ], + "type": "text", + "content": "RL has found success in the past in computer vision applications, we refer the interested reader to [24] for a comprehensive review. These approaches mainly use RL as an auxiliary unit with the goal of improving efficiency [68] or robustness [45]. We differ from these as we use RL to tune pre-trained models with the goal of aligning with a specified task-specific reward. Such tuning was concurrently shown to significantly boost performance for tasks such as object detection, among others [54]." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 541, + 130, + 555 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 541, + 130, + 555 + ], + "spans": [ + { + "bbox": [ + 47, + 541, + 130, + 555 + ], + "type": "text", + "content": "3. Methodology" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "spans": [ + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "type": "text", + "content": "We parametrize a road network as a graph " + }, + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "type": "inline_equation", + "content": "\\mathcal{G} = \\{\\mathcal{V},\\mathcal{E}\\}" + }, + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "type": "text", + "content": " with each vertex " + }, + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "type": "inline_equation", + "content": "v_{i} = [x_{i},y_{i}]^{\\top}\\in \\mathcal{V}" + }, + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "type": "text", + "content": " representing a key point on the road surface. The set of edges " + }, + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "type": "inline_equation", + "content": "(v_{i},v_{j})\\in \\mathcal{E}" + }, + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "type": "text", + "content": " corresponds to road segments connecting these key points. We can then generate a probability distribution over roads by following a two-step process: i) generation of a set of vertices and ii) generation of a set of edges connecting them. Formally, for an image " + }, + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "type": "inline_equation", + "content": "\\mathcal{I}" + }, + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "type": "text", + "content": ", a road network " + }, + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "type": "inline_equation", + "content": "\\mathcal{R}" + }, + { + "bbox": [ + 46, + 561, + 287, + 657 + ], + "type": "text", + "content": " is derived as:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 58, + 663, + 287, + 684 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 663, + 287, + 684 + ], + "spans": [ + { + "bbox": [ + 58, + 663, + 287, + 684 + ], + "type": "interline_equation", + "content": "\\mathcal {R} = \\underset {\\mathcal {V}, \\mathcal {E}} {\\arg \\max } P (\\mathcal {V}, \\mathcal {E} \\mid \\mathcal {I}) = P (\\mathcal {E} \\mid \\mathcal {V}, \\mathcal {I}) P (\\mathcal {V} \\mid \\mathcal {I}). \\tag {1}", + "image_path": "16c451aba6a2d573291b46ba74124af04fa0f805df3794470c00449042dbfa75.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 689, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 288, + 713 + ], + "type": "text", + "content": "The graph nodes typically correspond to local information in an image, and we therefore resort to a CNN-based model" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 227, + 545, + 286 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 227, + 545, + 286 + ], + "spans": [ + { + "bbox": [ + 304, + 227, + 545, + 286 + ], + "type": "text", + "content": "to extract key points, providing the set " + }, + { + "bbox": [ + 304, + 227, + 545, + 286 + ], + "type": "inline_equation", + "content": "\\mathcal{V}'" + }, + { + "bbox": [ + 304, + 227, + 545, + 286 + ], + "type": "text", + "content": ", that sufficiently captures the information in the ground truth graph " + }, + { + "bbox": [ + 304, + 227, + 545, + 286 + ], + "type": "inline_equation", + "content": "\\mathcal{G}" + }, + { + "bbox": [ + 304, + 227, + 545, + 286 + ], + "type": "text", + "content": ". The construction of edges, however, requires higher-level reasoning that can cope with parallel roads, junctions, occlusions, or poor image resolution, among other difficulties." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 287, + 545, + 323 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 287, + 545, + 323 + ], + "spans": [ + { + "bbox": [ + 304, + 287, + 545, + 323 + ], + "type": "text", + "content": "Considering probabilistic models over sequences and using the chain rule, we can factorize the joint distribution as the product of a series of conditional distributions" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 332, + 334, + 545, + 367 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 332, + 334, + 545, + 367 + ], + "spans": [ + { + "bbox": [ + 332, + 334, + 545, + 367 + ], + "type": "interline_equation", + "content": "P (\\mathcal {E} \\mid \\mathcal {V}, \\mathcal {I}; \\sigma) = \\prod_ {n = 1} ^ {N _ {\\mathcal {E}}} P \\left(e _ {\\sigma (n)} \\mid e _ {< \\sigma (n)}, \\mathcal {V}, \\mathcal {I}\\right), \\tag {2}", + "image_path": "9090dd8efd767fcc4b2a53484fe2b1bd770a78498e93c89b630c2bd5f29cd709.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "spans": [ + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "inline_equation", + "content": "e_{<\\sigma(n)}" + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "text", + "content": " represents " + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "inline_equation", + "content": "e_{\\sigma(1)}, e_{\\sigma(2)}, \\ldots, e_{\\sigma(n-1)}" + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "inline_equation", + "content": "\\sigma \\in S_{N_{\\mathcal{E}}}" + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "text", + "content": " denotes the set of all permutations of the integers " + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "inline_equation", + "content": "1, 2, \\ldots, N_{\\mathcal{E}}" + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "text", + "content": ", with " + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "inline_equation", + "content": "N_{\\mathcal{E}}" + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "text", + "content": " the number of edges. For our work we consider the setting where these sequences are upper bounded in length, i.e. " + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "inline_equation", + "content": "N_{\\mathcal{E}} \\leq N_{\\max}" + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "text", + "content": ", since we are dealing with satellite images of fixed size. Autoregressive models (ARMs) have been used to solve similar tasks in the past by defining a fixed order of decoding [39, 59, 36, 42]. In our case, this would correspond to sorting all key points by their coordinates " + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "inline_equation", + "content": "y" + }, + { + "bbox": [ + 304, + 378, + 546, + 521 + ], + "type": "text", + "content": " and generating edges for each of them sequentially. We call this the autoregressive order. There are, however, two major drawbacks." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 522, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 522, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 522, + 547, + 714 + ], + "type": "text", + "content": "First, the evaluation metrics used for this task define a buffer region in which nodes in the ground truth and the predicted graph are considered to be a match. Therefore, a newly generated edge can be only partially correct when only partially overlapping with the ground truth graph. This non-smooth feedback comes in clear contrast to the supervised training scheme of ARMs, minimization of the negative log-likelihood, that assumes perfect information regarding the key points' locations, i.e. that the sets " + }, + { + "bbox": [ + 304, + 522, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\mathcal{V}" + }, + { + "bbox": [ + 304, + 522, + 547, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 522, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\mathcal{V}'" + }, + { + "bbox": [ + 304, + 522, + 547, + 714 + ], + "type": "text", + "content": " are the same. In practice, this condition is rarely met as the exact spatial graph can be represented in arbitrarily many ways by subdividing long edges into smaller ones or due to small perturbation to key points' locations. It is thus imperative that our model can estimate the expected improvement of adding selected edges, which implicitly can also signal when to appropriately end the generation process." + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "text", + "content": "5410" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "content": "Second, the requirement to decode according to the autoregressive order introduces a bias and limits the expressiveness of the model [58]. As a result, it can lead to failures in cases with blurry inputs or occlusions [26]. We employ RL to overcome these deficiencies and align the model with the required objective. In more detail, we tune an autoregressive model, described in Section 3.1, with the ability to search into sequences of actions in the future, as described in Section 3.2. Our novel generic strategy improves the autoregressive model without requiring significantly more computational resources." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 207, + 170, + 218 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 207, + 170, + 218 + ], + "spans": [ + { + "bbox": [ + 47, + 207, + 170, + 218 + ], + "type": "text", + "content": "3.1. Autoregressive model" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 225, + 287, + 344 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 225, + 287, + 344 + ], + "spans": [ + { + "bbox": [ + 46, + 225, + 287, + 344 + ], + "type": "text", + "content": "We start by introducing a base autoregressive model, illustrated in Fig. 4. Given an image and a set of key points, i.e a set of vertices " + }, + { + "bbox": [ + 46, + 225, + 287, + 344 + ], + "type": "inline_equation", + "content": "\\mathcal{V}'" + }, + { + "bbox": [ + 46, + 225, + 287, + 344 + ], + "type": "text", + "content": ", our model produces a graph by sequentially predicting a list of indices corresponding to the graph's flattened, unweighted edge-list. Each forward pass produces probabilities over the set of key points, which leads to a new index after sampling. A successive pair of indices defines an edge as its two endpoints. A special end-of-sequence token is reserved to designate the end of the generation process." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 346, + 289, + 609 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 346, + 289, + 609 + ], + "spans": [ + { + "bbox": [ + 46, + 346, + 289, + 609 + ], + "type": "text", + "content": "Following [63, 53], we begin by extracting visual features per key point, by interpolating intermediate layers of a ResNet backbone to the key points' locations, which are further augmented by position encodings of their locations. We then further process these features using two Transformer modules. The first transformer (Transformer I in Fig. 4) encodes the raw features of the key points as embeddings. The second transformer (Transformer II in Fig. 4) takes as input the currently generated edge list sequence, corresponding to the currently partially generated graph. Edges are directly mapped to the embeddings of their comprising key points, supplemented by position and type embeddings, to differentiate between them, as shown in Fig. 5 (a). An additional global image embedding also extracted by the ResNet is used to initialize the sequence. The Transformer II module produces a single hidden state, which is linked with the " + }, + { + "bbox": [ + 46, + 346, + 289, + 609 + ], + "type": "inline_equation", + "content": "N_{\\mathcal{V}'} + 1" + }, + { + "bbox": [ + 46, + 346, + 289, + 609 + ], + "type": "text", + "content": " (corresponding to the provided key points, supplemented by the special end of the generation token) key points' embeddings by a pointer network [62], via a dot-product. This allows the generation of a probability distribution of variable length depending on the current set " + }, + { + "bbox": [ + 46, + 346, + 289, + 609 + ], + "type": "inline_equation", + "content": "\\mathcal{V}'" + }, + { + "bbox": [ + 46, + 346, + 289, + 609 + ], + "type": "text", + "content": ", instead of using a fixed action space." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 611, + 157, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 611, + 157, + 623 + ], + "spans": [ + { + "bbox": [ + 47, + 611, + 157, + 623 + ], + "type": "text", + "content": "3.2. Augmented search" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 629, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 287, + 714 + ], + "type": "text", + "content": "In order to address the problems of greedy decoding (analyzed in Section 3), we frame our road extraction task as a classical Markov-decision process (MDP). The generation of a graph for every image defines an environment, where the length of the currently generated edge list determines the current step. Let " + }, + { + "bbox": [ + 46, + 629, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\boldsymbol{o}_t" + }, + { + "bbox": [ + 46, + 629, + 287, + 714 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 629, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\alpha_t" + }, + { + "bbox": [ + 46, + 629, + 287, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 629, + 287, + 714 + ], + "type": "inline_equation", + "content": "r_t" + }, + { + "bbox": [ + 46, + 629, + 287, + 714 + ], + "type": "text", + "content": " correspond to the observation, the action, i.e. the selected key point index," + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "type": "text", + "content": "and the observed reward respectively, at time step " + }, + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "type": "text", + "content": ". The aim is to search for a policy that maximizes the expected cumulative reward over a horizon " + }, + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "type": "text", + "content": ", i.e., " + }, + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "type": "inline_equation", + "content": "\\max_{\\pi} J(\\pi) := \\mathbb{E}_{\\pi} \\left[ \\sum_{t=0}^{T-1} \\gamma^t r_t \\right]" + }, + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "type": "inline_equation", + "content": "\\gamma \\in (0,1]" + }, + { + "bbox": [ + 304, + 72, + 545, + 157 + ], + "type": "text", + "content": " indicates the discount factor and the expectation is with respect to the randomness in the policy and the transition dynamics. We set the discount factor to 1 due to the bounded time horizon." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 157, + 545, + 242 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 157, + 545, + 242 + ], + "spans": [ + { + "bbox": [ + 304, + 157, + 545, + 242 + ], + "type": "text", + "content": "Instead of training a reward model [41], we employ established graph-theoretic metrics that also allow the definition of intermediate rewards, accelerating initial training. More formally, each action leads to the selection of a new key point, with new edges being added once every two actions. The addition of a new edge leads to a revision of the predicted graph and triggers an intermediate reward" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 347, + 249, + 545, + 263 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 347, + 249, + 545, + 263 + ], + "spans": [ + { + "bbox": [ + 347, + 249, + 545, + 263 + ], + "type": "interline_equation", + "content": "r _ {t} = \\operatorname {s c} \\left(\\mathcal {G} _ {\\mathrm {g t}}, \\mathcal {G} _ {\\text {p r e d} _ {t}}\\right) - \\operatorname {s c} \\left(\\mathcal {G} _ {\\mathrm {g t}}, \\mathcal {G} _ {\\text {p r e d} _ {t - 1}}\\right), \\tag {3}", + "image_path": "bc8500c5951785e12d2ca7c76d3eee52e80ddf632614068792722e3c7edb3e6b.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 269, + 545, + 317 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 269, + 545, + 317 + ], + "spans": [ + { + "bbox": [ + 304, + 269, + 545, + 317 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 269, + 545, + 317 + ], + "type": "inline_equation", + "content": "\\operatorname{sc}(\\mathcal{G}_{\\mathrm{gt}}, \\mathcal{G}_{\\mathrm{pred}_t})" + }, + { + "bbox": [ + 304, + 269, + 545, + 317 + ], + "type": "text", + "content": " is a similarity score between the ground truth graph " + }, + { + "bbox": [ + 304, + 269, + 545, + 317 + ], + "type": "inline_equation", + "content": "\\mathcal{G}_{\\mathrm{gt}}" + }, + { + "bbox": [ + 304, + 269, + 545, + 317 + ], + "type": "text", + "content": " and the current estimate " + }, + { + "bbox": [ + 304, + 269, + 545, + 317 + ], + "type": "inline_equation", + "content": "\\mathcal{G}_{\\mathrm{pred}_t}" + }, + { + "bbox": [ + 304, + 269, + 545, + 317 + ], + "type": "text", + "content": ". Discussion of the specific similarity scores used in practice is postponed for Section 3.3." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 317, + 545, + 389 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 317, + 545, + 389 + ], + "spans": [ + { + "bbox": [ + 304, + 317, + 545, + 389 + ], + "type": "text", + "content": "A proper spatial graph generation entails (i) correct topology and (ii) accurate location prediction of individual roads. For the latter, intermediate vertices of degree 2 are essential. We call a road segment (RS), an ordered collection of edges, between vertices of degree " + }, + { + "bbox": [ + 304, + 317, + 545, + 389 + ], + "type": "inline_equation", + "content": "d(\\cdot)" + }, + { + "bbox": [ + 304, + 317, + 545, + 389 + ], + "type": "text", + "content": " two (or a collection of edges forming a circle):" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 333, + 396, + 517, + 455 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 333, + 396, + 517, + 455 + ], + "spans": [ + { + "bbox": [ + 333, + 396, + 517, + 455 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathrm {R S} = \\left\\{\\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {1}}, \\boldsymbol {v} _ {\\mathrm {r s} _ {2}}\\right), \\dots , \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {k - 1}}, \\boldsymbol {v} _ {\\mathrm {r s} _ {k}}\\right) \\right\\} \\\\ \\mathrm {s . t} \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {i}}, \\boldsymbol {v} _ {\\mathrm {r s} _ {i + 1}}\\right) \\in \\mathcal {E} \\text {f o r} i = 1, \\dots , k - 1 \\\\ d \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {i}}\\right) = 2, \\text {f o r} i = 2, \\dots k - 1, \\\\ \\left(d \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {1}}\\right) \\neq 2 \\text {a n d} d \\left(\\boldsymbol {v} _ {\\mathrm {r s} _ {k}}\\right) \\neq 2 \\text {o r} \\boldsymbol {v} _ {\\mathrm {r s} _ {1}} = \\boldsymbol {v} _ {\\mathrm {r s} _ {k}}\\right). \\\\ \\end{array}", + "image_path": "e7889baa4294d0b10a81b149b0dfe85384a29ff1beb244eee10b30d3e6c668cf.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 462, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 462, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 462, + 545, + 714 + ], + "type": "text", + "content": "During the progression of an episode (i.e. the sequential generation of a graph), the topological nature of the similarity scores in Eq. 3 implies that the effect of each new edge to the reward will be reflected mostly once its whole corresponding road segment has been generated. To resolve the ambiguity in the credit assignment and allow our agent to look ahead into sequences of actions, we rely on Monte Carlo Tree Search (MCTS) to simulate entire sequences of actions. We use a state-of-the-art search-based agent, MuZero [48], that constructs a learnable model of the environment dynamics, simulating transitions in this latent representation and leading to significant computational benefits. At every step, the enhanced model with its new components produces value [50] and reward estimates, which define an exploration strategy. Simulations into future sequences of actions are performed based on this strategy, helping the model to make decisions based on future outcomes, not yet experienced. Compared to a simpler PPO objective [49, 41], that in our experience did not lead to significant improvements, MCTS generates a series of simulations traversing the tree from a root node, generating more" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 750, + 314, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 750, + 314, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 750, + 314, + 758 + ], + "type": "text", + "content": "5411" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 130, + 70, + 465, + 236 + ], + "blocks": [ + { + "bbox": [ + 130, + 70, + 465, + 236 + ], + "lines": [ + { + "bbox": [ + 130, + 70, + 465, + 236 + ], + "spans": [ + { + "bbox": [ + 130, + 70, + 465, + 236 + ], + "type": "image", + "image_path": "5d674a1311acd3c4b95c744697c9304c3b0c023a027839930ef5e2ce5410de8a.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 239, + 547, + 298 + ], + "lines": [ + { + "bbox": [ + 46, + 239, + 547, + 298 + ], + "spans": [ + { + "bbox": [ + 46, + 239, + 547, + 298 + ], + "type": "text", + "content": "Figure 4. The autoregressive model with its three main components. (1) A backbone image model (ResNet) that extracts features for each key point at different scales, along with a global image embedding. (2) A key point model embeds visual and location features of distinct key points. (3) An edge embedding model relates the current edge sequence with the respective key points. Each edge token (signalled with the tokens 'index-i') corresponds to an index specifying the respective key point. A pair of such tokens designates an edge as its two endpoints. At the end of (3) we obtain a new distribution over key points that leads to an incremental update to the graph, after sampling." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 309, + 288, + 334 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 309, + 288, + 334 + ], + "spans": [ + { + "bbox": [ + 46, + 309, + 288, + 334 + ], + "type": "text", + "content": "stable value and reward estimates. MuZero requires three distinct parts (see also Fig. 5):" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 54, + 344, + 289, + 595 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 55, + 344, + 289, + 441 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 344, + 289, + 441 + ], + "spans": [ + { + "bbox": [ + 55, + 344, + 289, + 441 + ], + "type": "text", + "content": "1. A representation function " + }, + { + "bbox": [ + 55, + 344, + 289, + 441 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 55, + 344, + 289, + 441 + ], + "type": "text", + "content": " creates a latent vector of the current state " + }, + { + "bbox": [ + 55, + 344, + 289, + 441 + ], + "type": "inline_equation", + "content": "\\pmb{h}_t = f_\\theta(\\pmb{o}_t)" + }, + { + "bbox": [ + 55, + 344, + 289, + 441 + ], + "type": "text", + "content": ", in our case the autoregressive model, shown in Fig. 4. Our current latent representation " + }, + { + "bbox": [ + 55, + 344, + 289, + 441 + ], + "type": "inline_equation", + "content": "\\pmb{h}_t" + }, + { + "bbox": [ + 55, + 344, + 289, + 441 + ], + "type": "text", + "content": " contains the graph's hidden state along with the key points' embeddings used to map actions to latent vectors. As key points remain the same throughout the episode, image-based features (Components (1) and (2) in Fig. 4) are only computed once." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "spans": [ + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "type": "text", + "content": "2. A dynamics network " + }, + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "type": "inline_equation", + "content": "g" + }, + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "type": "text", + "content": ", we use a simple LSTM [20], as commonly done, that predicts the effect of a new action by predicting the next hidden state and the expected reward: " + }, + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "type": "inline_equation", + "content": "(\\hat{h}_t, \\hat{r}_t) = g_\\theta(\\hat{h}_{t-1}, \\alpha_t)" + }, + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "type": "text", + "content": ". We can replace " + }, + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\tilde{h}_{t-1}" + }, + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "type": "text", + "content": " with the latent representation " + }, + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "type": "inline_equation", + "content": "h_{t-1}" + }, + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "type": "text", + "content": ", or its previous computed approximation " + }, + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "type": "inline_equation", + "content": "\\hat{h}_{t-1}" + }, + { + "bbox": [ + 54, + 445, + 287, + 529 + ], + "type": "text", + "content": " for tree search of depth larger than 1." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 54, + 535, + 288, + 595 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 535, + 288, + 595 + ], + "spans": [ + { + "bbox": [ + 54, + 535, + 288, + 595 + ], + "type": "text", + "content": "3. A prediction network " + }, + { + "bbox": [ + 54, + 535, + 288, + 595 + ], + "type": "inline_equation", + "content": "\\psi" + }, + { + "bbox": [ + 54, + 535, + 288, + 595 + ], + "type": "text", + "content": ", that estimates the policy and the value for the current state " + }, + { + "bbox": [ + 54, + 535, + 288, + 595 + ], + "type": "inline_equation", + "content": "(\\pmb{p}_{t+1}, v_t) = \\psi_\\theta(\\tilde{\\pmb{h}}_t)" + }, + { + "bbox": [ + 54, + 535, + 288, + 595 + ], + "type": "text", + "content": ". We compute the policy via a pointer network as described in Section 3.1. Value estimates are produced by a simple multi-layer perceptron." + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "content": "The dynamics network guides the search and evaluates the expected reward of actions. For every newly generated edge, we also explicitly inform the network regarding the creation of new intersections and the expected relative change in the overall road surface generated via embeddings (see Fig. 5). By using the dynamics network, we bypass the expensive call to the decoder module during the search, and can instead approximate small modifications in the latent representation directly. For our experiments, the dynamics" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 310, + 308, + 544, + 425 + ], + "blocks": [ + { + "bbox": [ + 310, + 308, + 544, + 425 + ], + "lines": [ + { + "bbox": [ + 310, + 308, + 544, + 425 + ], + "spans": [ + { + "bbox": [ + 310, + 308, + 544, + 425 + ], + "type": "image", + "image_path": "bacb4f43b159a22feb9ec2adcd9e94fabbebc9be883d27232656d909cdeecc40.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 426, + 547, + 548 + ], + "lines": [ + { + "bbox": [ + 304, + 426, + 547, + 548 + ], + "spans": [ + { + "bbox": [ + 304, + 426, + 547, + 548 + ], + "type": "text", + "content": "Figure 5. The autoregressive model generates a hidden state corresponding to the graph embedding. (a) When doing so, the edge decoder directly attends to the input key points' embeddings, augmented by position and type embeddings. (b) The prediction network uses the hidden state to produce value and policy predictions. A pointer network allows an intuitive scale of the action space by the number of key points. (c) The dynamics network simulates trajectories by estimating new hidden states and rewards. For newly generated edges, it takes as input the embeddings of the new key points, but also the degree of the two vertices involved and the length of the newly proposed generated edge." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 562, + 547, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 562, + 547, + 647 + ], + "spans": [ + { + "bbox": [ + 304, + 562, + 547, + 647 + ], + "type": "text", + "content": "network requires up to 90 times less floating-point operations to simulate trajectories, compared to using the edge embeddings' decoder. Effectively, our method does not involve significantly more computation budget compared to the base autoregressive model. More details regarding the MuZero training and exploration are provided in Section 4 and in the appendix." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 658, + 417, + 670 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 658, + 417, + 670 + ], + "spans": [ + { + "bbox": [ + 306, + 658, + 417, + 670 + ], + "type": "text", + "content": "3.3. Evaluation metrics" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 677, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 547, + 715 + ], + "type": "text", + "content": "We adopt the same evaluation metrics both as a comparison between different methods and to determine the reward for our agent, through Eq. 3. We use the relaxed versions of" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "text", + "content": "5412" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "content": "precision, recall, and intersection over union for pixel-level predictions Correctness/Completeness/Quality (CCQ) [66, 64]. As graph-theoretic metrics we use APLS [60] and additionally include new metrics introduced in [14] that compare Paths, Junctions and Sub-graphs of the graphs in question, producing respectively precision, recall and " + }, + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "inline_equation", + "content": "f_{1}" + }, + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "content": " scores. More details can be found in the appendix." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 170, + 128, + 184 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 170, + 128, + 184 + ], + "spans": [ + { + "bbox": [ + 47, + 170, + 128, + 184 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 191, + 287, + 370 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 191, + 287, + 370 + ], + "spans": [ + { + "bbox": [ + 46, + 191, + 287, + 370 + ], + "type": "text", + "content": "Implementation details. We resize images to " + }, + { + "bbox": [ + 46, + 191, + 287, + 370 + ], + "type": "inline_equation", + "content": "300 \\times 300" + }, + { + "bbox": [ + 46, + 191, + 287, + 370 + ], + "type": "text", + "content": " pixels, standardizing according to the training set statistics. For exploration, we initialize workers using Ray [33] that execute episodes in the environment. For training, we unroll the dynamics function for " + }, + { + "bbox": [ + 46, + 191, + 287, + 370 + ], + "type": "inline_equation", + "content": "t_d = 5" + }, + { + "bbox": [ + 46, + 191, + 287, + 370 + ], + "type": "text", + "content": " steps and use priority weights for the episode according to the differences between predicted and target values. Our algorithm can be considered as an approximate on-policy TD(" + }, + { + "bbox": [ + 46, + 191, + 287, + 370 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 191, + 287, + 370 + ], + "type": "text", + "content": ") [55] due to the relatively small replay buffer. We reanalyse older games [48] to provide fresher target estimates. Unvisited graph nodes are selected based on an upper confidence score, balancing exploration with exploitation, similar to [51]. We add exploration noise as Dirichlet noise and select actions based on a temperature-controlled sampling procedure, whose temperature is reduced during training." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 372, + 288, + 635 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 372, + 288, + 635 + ], + "spans": [ + { + "bbox": [ + 46, + 372, + 288, + 635 + ], + "type": "text", + "content": "Given the limited high-quality available ground truth labels [52] and to accelerate training, we employ modifications introduced in EfficientZero [71]. We investigate adding supervision to the environment model and better initialize Q-value predictions similar to the implementation of Elf OpenGo [57]. We further scale values and rewards using an invertible transform inspired by [44]. Here, we predict support, as fully connected networks are biased towards learning low-frequency representations [21]. Selecting new actions involves generating simulations that can be done expeditiously given the small dimension of the latent space and the modest size of the dynamics network. Finally, to generate key points, we skeletonize segmentation masks provided by any baseline segmentation model, by thresholding the respective segmentation masks produced and applying RDP-simplification [17, 46]. Selecting an appropriate threshold and subdividing larger edges guarantees that the generated set " + }, + { + "bbox": [ + 46, + 372, + 288, + 635 + ], + "type": "inline_equation", + "content": "\\mathcal{V}'" + }, + { + "bbox": [ + 46, + 372, + 288, + 635 + ], + "type": "text", + "content": " adequately captures most of the ground truth road network, leaving the complexity of the problem for our model to handle. We will use the term ARM to denote the autoregressive model and Ours for the RL-tuned model." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 646, + 149, + 658 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 646, + 149, + 658 + ], + "spans": [ + { + "bbox": [ + 47, + 646, + 149, + 658 + ], + "type": "text", + "content": "4.1. Synthetic dataset" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "type": "text", + "content": "Initially, a simplified setting is chosen wherein the complete governance of both the nature and intensity of the difficulty inherent in the road-extraction task can be regulated. We generate a dataset of overhead satellite images of a syn" + } + ] + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 307, + 71, + 545, + 220 + ], + "blocks": [ + { + "bbox": [ + 307, + 71, + 545, + 220 + ], + "lines": [ + { + "bbox": [ + 307, + 71, + 545, + 220 + ], + "spans": [ + { + "bbox": [ + 307, + 71, + 545, + 220 + ], + "type": "image", + "image_path": "d4914a2d2c86ee8ef4099f953c98ae4debab9d3d3bae666611cee750869bd331.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 222, + 546, + 300 + ], + "lines": [ + { + "bbox": [ + 304, + 222, + 546, + 300 + ], + "spans": [ + { + "bbox": [ + 304, + 222, + 546, + 300 + ], + "type": "text", + "content": "Figure 6. (Left) Examples of fragmented outputs from the LinkNet model under cases of significant occlusion and how our approach performs in these demanding circumstances. (Right) The performance gap between our method and the same baseline is wide, based on topological spatial graph metrics, for a wide range of difficulties in the images. More details and examples are given in the supplementary material." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 312, + 546, + 418 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 312, + 546, + 418 + ], + "spans": [ + { + "bbox": [ + 304, + 312, + 546, + 418 + ], + "type": "text", + "content": "thetic town using CityEngine1. We randomly specify vegetation of varying height and width along the side walks of the generated streets, leading inadvertently to occlusions of varying difficulty. The simulated environment allows specifying pixel-perfect masks regarding both roads and trees occluding the road surface based on the provided camera parameters [23]. We defer more details regarding the generation process and dataset examples to the supplementary material." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 420, + 545, + 587 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 420, + 545, + 587 + ], + "spans": [ + { + "bbox": [ + 304, + 420, + 545, + 587 + ], + "type": "text", + "content": "We compare our method by training on our dataset a LinkNet model [10], a popular segmentation model that has been widely used in the remote sensing community [25]. Even in this synthetic and thus less diverse scenario, the deficiency of segmentation models to rely mostly on local information, with no explicit ability for longer-range interactions, is evident. Fig. 6 illustrates examples of such oversegmented predictions and how our approach can improve on them. We also define a 'difficulty' attribute per synthetic satellite image, quantifying the occlusions as a percentage of the ground truth road mask covered. We observe a considerable absolute improvement in topological metric scores when training our model on this synthetic dataset, compared to the baseline, for varying image difficulty." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 595, + 391, + 607 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 595, + 391, + 607 + ], + "spans": [ + { + "bbox": [ + 306, + 595, + 391, + 607 + ], + "type": "text", + "content": "4.2. Real datasets" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 613, + 545, + 686 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 613, + 545, + 686 + ], + "spans": [ + { + "bbox": [ + 304, + 613, + 545, + 686 + ], + "type": "text", + "content": "We assess our approach on the SpaceNet and DeepGlobe datasets. A single image is provided to our method, with a spatial graph being generated as the output. We use the same train-test splits as in [8] to promote reproducibility, while results are reported for the final combined graph on the original image scale. No pre-training on the synthetic" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 306, + 693, + 487, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 693, + 487, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 693, + 487, + 713 + ], + "type": "text", + "content": "1https://www.esri.com/en-us/arcgis/products/arcgis-cityengine/overview" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "text", + "content": "5413" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 49, + 71, + 547, + 182 + ], + "blocks": [ + { + "bbox": [ + 49, + 71, + 547, + 182 + ], + "lines": [ + { + "bbox": [ + 49, + 71, + 547, + 182 + ], + "spans": [ + { + "bbox": [ + 49, + 71, + 547, + 182 + ], + "type": "table", + "html": "
MethodCCQTLTSAPLS ↑Path-BasedJunction-BasedSub-graph-Based f1 ↑
corr. ↑comp. ↑qual. ↑corr. ↑2l+2s ↓pre. ↑rec. ↑f1 ↑pre. ↑rec. ↑f1 ↑
SpaceNetDeepRoadMapper [29]0.69430.68380.53860.41100.10120.51430.59580.64000.61710.62930.74430.68200.6783
Segmentation [28, 22]0.74930.70940.59690.41430.08280.54540.69090.68630.68850.71860.77100.74380.7117
LinkNet [10]0.81000.74490.64090.48940.07430.57430.67190.64600.65860.69850.78090.73740.7576
Orientation [8]0.80700.80010.68620.55940.08840.63150.71750.72800.72270.75520.75910.75710.7802
Sat2Graph [18]**0.69170.73510.57340.58020.11040.59510.59520.54160.56710.74740.59510.66260.7180
SPIN road mapper [5]0.78370.79880.66210.59220.10580.64220.72760.72650.72700.76210.78270.77220.7837
Ours0.81500.80920.69320.59700.07320.65870.73830.76130.74960.78450.78210.78330.7948
DeepGlobeLinkNet [10]0.80120.86760.73280.66400.08040.65250.68820.69200.69010.76750.74440.75580.7879
Orientation [8]0.82430.88570.75450.68660.10470.70120.69370.80820.74650.76240.79390.77780.8282
Ours*0.82230.89790.74940.72420.07430.74000.71500.82740.76710.79120.82830.80930.8391
", + "image_path": "4d972e860e96a85d053dca875319e3a60b83a5cec687b44911a4cbdd42a09090.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 52, + 183, + 355, + 190 + ], + "lines": [ + { + "bbox": [ + 52, + 183, + 355, + 190 + ], + "spans": [ + { + "bbox": [ + 52, + 183, + 355, + 190 + ], + "type": "text", + "content": "* We do not fine-tune our model on the DeepGlobe dataset but instead refine predictions standardizing according to train dataset statistics." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + }, + { + "bbox": [ + 52, + 191, + 541, + 206 + ], + "lines": [ + { + "bbox": [ + 52, + 191, + 541, + 206 + ], + "spans": [ + { + "bbox": [ + 52, + 191, + 541, + 206 + ], + "type": "text", + "content": "** The authors provided predictions corresponding only to a center crop of the original SpaceNet dataset images. Also, note that the test set is different from the one reported on the rest of the methods, see also the appendix. Blue: best score, Green: second best score, Gray: results reported in different test set" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 52, + 236, + 538, + 392 + ], + "blocks": [ + { + "bbox": [ + 167, + 217, + 425, + 228 + ], + "lines": [ + { + "bbox": [ + 167, + 217, + 425, + 228 + ], + "spans": [ + { + "bbox": [ + 167, + 217, + 425, + 228 + ], + "type": "text", + "content": "Table 1. Quantitative results for the SpaceNet and DeepGlobe datasets." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 52, + 236, + 538, + 392 + ], + "lines": [ + { + "bbox": [ + 52, + 236, + 538, + 392 + ], + "spans": [ + { + "bbox": [ + 52, + 236, + 538, + 392 + ], + "type": "table", + "html": "
DeepRoadMapper [29]Segmentation [22]Orientation [8]OursGround TruthSatellite Image
", + "image_path": "26afb835f5a84cf49902e1293758675f95315d8a463fa61175a66eb50e41b3e6.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 424, + 288, + 513 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 424, + 288, + 513 + ], + "spans": [ + { + "bbox": [ + 46, + 424, + 288, + 513 + ], + "type": "text", + "content": "Table 3. APLS metric and perplexity (bits of information per edge) results for the SpaceNet dataset with provided key points that adequately capture the ground truth graph. Autoregressive order is defined in Section 3, while random order entails random permutation between edges and the order of key points within edges. To calculate perplexity for our method we use the initial predicted policy distribution, without any additional search. More details on baselines and general approach are presented in the appendix." + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 48, + 514, + 293, + 566 + ], + "blocks": [ + { + "bbox": [ + 118, + 395, + 474, + 406 + ], + "lines": [ + { + "bbox": [ + 118, + 395, + 474, + 406 + ], + "spans": [ + { + "bbox": [ + 118, + 395, + 474, + 406 + ], + "type": "text", + "content": "Table 2. Qualitative results of improved connectivity. We recommend zooming in for more details." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 514, + 293, + 566 + ], + "lines": [ + { + "bbox": [ + 48, + 514, + 293, + 566 + ], + "spans": [ + { + "bbox": [ + 48, + 514, + 293, + 566 + ], + "type": "table", + "html": "
Method MetricRandomClsGCNARMOurs
APLS0.0080.4300.5940.8940.928
Bits per edge: Autoregressive order8.743--0.5284.321
Bits per edge: Random order8.743--28.744.432
", + "image_path": "3534d6f9d77f3d939cf7206bc12e9c2c7b429b9c5b3e85699770c3140bc4062f.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 588, + 127, + 600 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 588, + 127, + 600 + ], + "spans": [ + { + "bbox": [ + 47, + 588, + 127, + 600 + ], + "type": "text", + "content": "dataset takes place." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 620, + 186, + 633 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 620, + 186, + 633 + ], + "spans": [ + { + "bbox": [ + 47, + 620, + 186, + 633 + ], + "type": "text", + "content": "4.2.1 Comparison to Baselines" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "text", + "content": "We initially train the ARM model on ground-truth graph information by using a set of key points " + }, + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{V}' = \\mathcal{V}" + }, + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "text", + "content": ". Even in this scenario, RL tuning increases the semantic quality of the extracted graphs as seen in Table 3. In cases where the set " + }, + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{V}'" + }, + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "text", + "content": " is imperfect, and for reasons elaborated in Section 3, newly proposed edges may be only partially correct. Under" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 427, + 545, + 595 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 427, + 545, + 595 + ], + "spans": [ + { + "bbox": [ + 304, + 427, + 545, + 595 + ], + "type": "text", + "content": "such circumstances, supervised training is infeasible, hence we rely on RL to produce the graph that leads to the maximum cumulative reward, i.e. our selected evaluation metrics. We conduct comparative analysis against the following approaches; we explore powerful CNN architectures, by training a Segmentation model with a ResNet backbone. We evaluate DeepRoadMapper [29], a model that refines previous segmentation by adding connections along possible identified paths. As done by [8] we notice that in complex scenarios, the effect of this post-processing step is not always positive. We also evaluate against LinkNet [10], and Orientation [8], which is trained to predict simultaneously road surfaces and orientation, and the relevant baselines [18, 5]." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 605, + 546, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 546, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 546, + 715 + ], + "type": "text", + "content": "Quantitative results in Table 1 and visual inspection in Table 2, affirm that the global context and the gradual generation incite a better understanding of the scene, leading to consistently outperforming topological metric results compared to the baselines. We remark that our predictions are more topologically consistent with fewer shortcomings, such as double roads, fragmented roads, and overconnections. This is further supplemented by comparing the statistics of the predicted spatial graphs in Fig. 7. We further" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "text", + "content": "5414" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 70, + 152, + 148 + ], + "blocks": [ + { + "bbox": [ + 51, + 70, + 152, + 148 + ], + "lines": [ + { + "bbox": [ + 51, + 70, + 152, + 148 + ], + "spans": [ + { + "bbox": [ + 51, + 70, + 152, + 148 + ], + "type": "image", + "image_path": "37842d88c031a521df9c6fe696804a521702307cf1bb47ca41bcfa99c313e436.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 151, + 547, + 195 + ], + "lines": [ + { + "bbox": [ + 46, + 151, + 547, + 195 + ], + "spans": [ + { + "bbox": [ + 46, + 151, + 547, + 195 + ], + "type": "text", + "content": "Figure 7. (Left) Comparison of generated graph statistics, following the same post-processing, averaged across regions of " + }, + { + "bbox": [ + 46, + 151, + 547, + 195 + ], + "type": "inline_equation", + "content": "400 \\times 400" + }, + { + "bbox": [ + 46, + 151, + 547, + 195 + ], + "type": "text", + "content": " meters in ground distance. Orientation refers to the method of [8]. (Right) The estimated Pareto front achieved through the evaluation of various runs, where a different number of MCTS simulations is being executed at each state. obj refers to an average of the APLS, Path-based f1, Junction-based f1 and Sub-graph-based f1 metrics." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 155, + 70, + 245, + 148 + ], + "blocks": [ + { + "bbox": [ + 155, + 70, + 245, + 148 + ], + "lines": [ + { + "bbox": [ + 155, + 70, + 245, + 148 + ], + "spans": [ + { + "bbox": [ + 155, + 70, + 245, + 148 + ], + "type": "image", + "image_path": "7783eeeec9752c14d156a15f5840c3d2730140225ee8e446bc75b44c33302a6f.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 247, + 71, + 342, + 148 + ], + "blocks": [ + { + "bbox": [ + 247, + 71, + 342, + 148 + ], + "lines": [ + { + "bbox": [ + 247, + 71, + 342, + 148 + ], + "spans": [ + { + "bbox": [ + 247, + 71, + 342, + 148 + ], + "type": "image", + "image_path": "f97b8cb663405ceba97add71edc6f0c7a85ea2b40a2d193c289022895b126dba.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 344, + 72, + 437, + 148 + ], + "blocks": [ + { + "bbox": [ + 344, + 72, + 437, + 148 + ], + "lines": [ + { + "bbox": [ + 344, + 72, + 437, + 148 + ], + "spans": [ + { + "bbox": [ + 344, + 72, + 437, + 148 + ], + "type": "image", + "image_path": "aa7767f3b065226d13532d14cfc3f77db60de60704f7197aa1cacba5a42a6e4e.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 457, + 70, + 543, + 148 + ], + "blocks": [ + { + "bbox": [ + 457, + 70, + 543, + 148 + ], + "lines": [ + { + "bbox": [ + 457, + 70, + 543, + 148 + ], + "spans": [ + { + "bbox": [ + 457, + 70, + 543, + 148 + ], + "type": "image", + "image_path": "59f6217c578e90777964331a4c268c7a5a5f65a975e2a5604c1ea11fd5b1f4f8.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 209, + 289, + 305 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 209, + 289, + 305 + ], + "spans": [ + { + "bbox": [ + 46, + 209, + 289, + 305 + ], + "type": "text", + "content": "showcase the transferability of our model by employing it with no fine-tuning (apart from dataset-specific image normalization) on the DeepGlobe dataset. We can refine previous predictions by adding missing edges, leading to more accurate spatial graph predictions, as shown in Table 1. Our conjecture that road structures and their geometric features exhibit a high degree of recurrence across various locations and geographic regions worldwide is thus confirmed." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 320, + 144, + 332 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 320, + 144, + 332 + ], + "spans": [ + { + "bbox": [ + 47, + 320, + 144, + 332 + ], + "type": "text", + "content": "4.2.2 Ablation study" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 341, + 287, + 484 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 341, + 287, + 484 + ], + "spans": [ + { + "bbox": [ + 46, + 341, + 287, + 484 + ], + "type": "text", + "content": "We experimented attending to image features for the two transformer modules by extracting per-patch visual features from the conditioning image " + }, + { + "bbox": [ + 46, + 341, + 287, + 484 + ], + "type": "inline_equation", + "content": "H^{\\mathrm{img}} = [h_1^{\\mathrm{img}}, h_2^{\\mathrm{img}}, \\ldots]" + }, + { + "bbox": [ + 46, + 341, + 287, + 484 + ], + "type": "text", + "content": ", as done in the Vision Transformer [16]. This did not lead to significant improvements, which we attribute to over-fitting. In Table. 4 we highlight the relative importance of some additional components for the final predictions. As efficiency is also of particular importance to us, we further visualize the effect of varying the simulation depth of the dynamics network during training (Fig. 7 (right)). Surprisingly perhaps, our method performs consistently even with a limited number of simulations." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 486, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 486, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 486, + 288, + 713 + ], + "type": "text", + "content": "In the appendix, we provide incremental results for the task of predicting road networks based on an optimal set of key points and insights concerning interpretability and further comparison to baselines based on the varying difficulty of the predicted underlying road networks. We also give more information regarding the generation of the synthetic dataset and the model architecture. Finally, we provide more implementation decisions, including details on exactly how key points and generated and how individual patch-level predictions are fused together. It is important to emphasize that our proposed method can operate effectively even when working with partially initialized predictions, making it a practical refinement approach that can be applied to existing baselines. By initializing our model based on the ARM model, we can achieve a rapid fine-tuning phase. Additionally, by utilizing the learned environment model, which avoids the need for expensive calls to the edge embedding model at each simulation step in MCTS, we can train the model even using a single GPU." + } + ] + } + ], + "index": 9 + }, + { + "type": "table", + "bbox": [ + 306, + 207, + 553, + 270 + ], + "blocks": [ + { + "bbox": [ + 306, + 207, + 553, + 270 + ], + "lines": [ + { + "bbox": [ + 306, + 207, + 553, + 270 + ], + "spans": [ + { + "bbox": [ + 306, + 207, + 553, + 270 + ], + "type": "table", + "html": "
ModelAPLSP-f1J-f1S-f1
Ours0.65870.74960.78330.7948
- autoregressive pre-training-15.3%-13.7%-14.1%-13.3%
- visual features for key-points-13.4%-12.7%-12.1%-12.3%
- tree-search during evaluation-2.1%-1.4%-1.7%-1.1%
+ cross attend to image features+0.2%-0.4%-0.7%-0.3%
", + "image_path": "616d8845943d035e4be6a60301021e06fb2205a1c6a8f27827dfd820baa678c2.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 306, + 273, + 457, + 282 + ], + "lines": [ + { + "bbox": [ + 306, + 273, + 457, + 282 + ], + "spans": [ + { + "bbox": [ + 306, + 273, + 457, + 282 + ], + "type": "text", + "content": "P: Path-based, J: Junction-based, S: Sub-graph-based" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 10 + }, + { + "bbox": [ + 341, + 291, + 511, + 302 + ], + "lines": [ + { + "bbox": [ + 341, + 291, + 511, + 302 + ], + "spans": [ + { + "bbox": [ + 341, + 291, + 511, + 302 + ], + "type": "text", + "content": "Table 4. Ablations study on SpaceNet dataset." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 334, + 384, + 346 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 334, + 384, + 346 + ], + "spans": [ + { + "bbox": [ + 306, + 334, + 384, + 346 + ], + "type": "text", + "content": "5. Conclusions" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 360, + 545, + 564 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 360, + 545, + 564 + ], + "spans": [ + { + "bbox": [ + 304, + 360, + 545, + 564 + ], + "type": "text", + "content": "We presented a reinforcement learning framework for tuning autoregressive tasks for the task of generating a graph as a variable-length edge sequence, where a structured-aware decoder selects new edges by simulating action sequences into the future. Importantly, this allows the model to better capture the geometry of the targeted objects. One advantage of the proposed method is that the reward function is based on (non-continuous) metrics that are directly connected to the application in question. Our approach does not require significantly more computational resources compared to state-of-the-art supervised approaches, and in addition, it can be used to refine predictions from another given model. We also remark that the direct prediction of a graph enables the concurrent prediction of meta-information about the edges, including, for instance, the type of road (e.g. highway, primary or secondary street, biking lane)." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 546, + 713 + ], + "type": "text", + "content": "Our approach opens the door to several directions for future work. For example, we have assumed that a pre-defined model gives the location of key points, but one could instead augment the action space to propose new key points' locations. Other promising directions include the direct prediction of input-dependent graph primitives, e.g. T-junctions or roundabouts. Finally, we emphasize that our approach is suitable for a wide variety of applications where autoregressive models are typically used, which we intend to look into in the future. Such applications include among others, Scene Graph Generation [67, 70] and Visual reasoning/Factual Visual Question Answering [11, 35]." + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "text", + "content": "5415" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 197, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 197, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 197, + 85 + ], + "type": "text", + "content": "6. Reproducibility Statement" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 91, + 287, + 140 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 91, + 287, + 140 + ], + "spans": [ + { + "bbox": [ + 47, + 91, + 287, + 140 + ], + "type": "text", + "content": "We have taken multiple steps to ensure the reproducibility of the experiments. We refer the reader to the appendix for a complete description of the training protocol. We have also released the code as part of the supplementary material." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 149, + 106, + 162 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 149, + 106, + 162 + ], + "spans": [ + { + "bbox": [ + 48, + 149, + 106, + 162 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 170, + 286, + 713 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 53, + 170, + 286, + 201 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 170, + 286, + 201 + ], + "spans": [ + { + "bbox": [ + 53, + 170, + 286, + 201 + ], + "type": "text", + "content": "[1] Samira Abnar and Willem Zuidema. Quantifying attention flow in transformers. arXiv preprint arXiv:2005.00928, 2020." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 203, + 286, + 257 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 203, + 286, + 257 + ], + "spans": [ + { + "bbox": [ + 53, + 203, + 286, + 257 + ], + "type": "text", + "content": "[2] David Acuna, Amlan Kar, and Sanja Fidler. Devil is in the edges: Learning semantic boundaries from noisy annotations. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11075-11083, 2019." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 258, + 286, + 312 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 258, + 286, + 312 + ], + "spans": [ + { + "bbox": [ + 53, + 258, + 286, + 312 + ], + "type": "text", + "content": "[3] Nicolas Audebert, Bertrand Le Saux, and Sébastien Lefèvre. Joint learning from earth observation and openstreetmap data to get faster better semantic maps. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 67-75, 2017." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 315, + 286, + 369 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 315, + 286, + 369 + ], + "spans": [ + { + "bbox": [ + 53, + 315, + 286, + 369 + ], + "type": "text", + "content": "[4] Yuntao Bai, Andy Jones, Kamal Ndousse, Amanda Askell, Anna Chen, Nova DasSarma, Dawn Drain, Stanislav Fort, Deep Ganguli, Tom Henighan, et al. Training a helpful and harmless assistant with reinforcement learning from human feedback. arXiv preprint arXiv:2204.05862, 2022." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 370, + 286, + 435 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 370, + 286, + 435 + ], + "spans": [ + { + "bbox": [ + 53, + 370, + 286, + 435 + ], + "type": "text", + "content": "[5] Wele Gedara Chaminda Bandara, Jeya Maria Jose Valanarasu, and Vishal M Patel. Spin road mapper: Extracting roads from aerial images via spatial and interaction space graph reasoning for autonomous driving. In 2022 International Conference on Robotics and Automation (ICRA), pages 343-350. IEEE, 2022." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 437, + 286, + 480 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 437, + 286, + 480 + ], + "spans": [ + { + "bbox": [ + 53, + 437, + 286, + 480 + ], + "type": "text", + "content": "[6] Meir Barzohar and David B Cooper. Automatic finding of main roads in aerial images by using geometric-stochastic models and estimation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 18(7):707-721, 1996." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 481, + 286, + 546 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 481, + 286, + 546 + ], + "spans": [ + { + "bbox": [ + 53, + 481, + 286, + 546 + ], + "type": "text", + "content": "[7] Favyen Bastani, Songtao He, Sofiane Abbar, Mohammad Al-izadeh, Hari Balakrishnan, Sanjay Chawla, Sam Madden, and David DeWitt. Roadtracer: Automatic extraction of road networks from aerial images. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4720–4728, 2018." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 548, + 286, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 548, + 286, + 602 + ], + "spans": [ + { + "bbox": [ + 53, + 548, + 286, + 602 + ], + "type": "text", + "content": "[8] Anil Batra, Suriya Singh, Guan Pang, Saikat Basu, CV Jawahar, and Manohar Paluri. Improved road connectivity by joint learning of orientation and segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10385-10393, 2019." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 53, + 603, + 286, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 603, + 286, + 668 + ], + "spans": [ + { + "bbox": [ + 53, + 603, + 286, + 668 + ], + "type": "text", + "content": "[9] Cameron B Browne, Edward Powley, Daniel Whitehouse, Simon M Lucas, Peter I Cowling, Philipp Rohlfshagen, Stephen Tavener, Diego Perez, Spyridon Samothrakis, and Simon Colton. A survey of monte carlo tree search methods. IEEE Transactions on Computational Intelligence and AI in games, 4(1):1-43, 2012." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 670, + 286, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 286, + 713 + ], + "type": "text", + "content": "[10] Abhishek Chaurasia and Eugenio Culurciello. Linknet: Exploiting encoder representations for efficient semantic segmentation. In 2017 IEEE Visual Communications and Image Processing (VCIP), pages 1-4. IEEE, 2017." + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 27, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "text", + "content": "[11] Xinlei Chen, Li-Jia Li, Li Fei-Fei, and Abhinav Gupta. Iterative visual reasoning beyond convolutions. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 7239-7248, 2018." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 118, + 545, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 545, + 162 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 545, + 162 + ], + "type": "text", + "content": "[12] Benjamin E Childs, James H Brodeur, and Levente Kocsis. Transpositions and move groups in monte carlo tree search. In 2008 IEEE Symposium On Computational Intelligence and Games, pages 389-395. IEEE, 2008." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 163, + 545, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 163, + 545, + 217 + ], + "spans": [ + { + "bbox": [ + 307, + 163, + 545, + 217 + ], + "type": "text", + "content": "[13] Hang Chu, Daiqing Li, David Acuna, Amlan Kar, Maria Shugrina, Xinkai Wei, Ming-Yu Liu, Antonio Torralba, and Sanja Fidler. Neural turtle graphics for modeling city road layouts. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4522-4530, 2019." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 220, + 545, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 220, + 545, + 262 + ], + "spans": [ + { + "bbox": [ + 307, + 220, + 545, + 262 + ], + "type": "text", + "content": "[14] Leonardo Citraro, Mateusz Kozinski, and Pascal Fua. Towards reliable evaluation of algorithms for road network reconstruction from aerial images. In European Conference on Computer Vision, pages 703-719. Springer, 2020." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 264, + 545, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 264, + 545, + 330 + ], + "spans": [ + { + "bbox": [ + 307, + 264, + 545, + 330 + ], + "type": "text", + "content": "[15] Ilke Demir, Krzysztof Koperski, David Lindenbaum, Guan Pang, Jing Huang, Saikat Basu, Forest Hughes, Devis Tuia, and Ramesh Raskar. Deep globe 2018: A challenge to parse the earth through satellite images. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 172-181, 2018." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 332, + 545, + 396 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 332, + 545, + 396 + ], + "spans": [ + { + "bbox": [ + 307, + 332, + 545, + 396 + ], + "type": "text", + "content": "[16] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 399, + 545, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 399, + 545, + 453 + ], + "spans": [ + { + "bbox": [ + 307, + 399, + 545, + 453 + ], + "type": "text", + "content": "[17] David H Douglas and Thomas K Peucker. Algorithms for the reduction of the number of points required to represent a digitized line or its caricature. Cartographica: the international journal for geographic information and geovisualization, 10(2):112-122, 1973." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 455, + 545, + 520 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 455, + 545, + 520 + ], + "spans": [ + { + "bbox": [ + 307, + 455, + 545, + 520 + ], + "type": "text", + "content": "[18] Songtao He, Favyen Bastani, Satvat Jagwani, Mohammad Alizadeh, Hari Balakrishnan, Sanjay Chawla, Mohamed M Elshrif, Samuel Madden, and Mohammad Amin Sadeghi. Sat2graph: Road graph extraction through graph-tensor encoding. In European Conference on Computer Vision, pages 51-67. Springer, 2020." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 522, + 545, + 564 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 522, + 545, + 564 + ], + "spans": [ + { + "bbox": [ + 307, + 522, + 545, + 564 + ], + "type": "text", + "content": "[19] Stefan Hinz and Albert Baumgartner. Automatic extraction of urban road networks from multi-view aerial imagery. IS-PRS journal of photogrammetry and remote sensing, 58(1-2):83-98, 2003." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 567, + 545, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 567, + 545, + 588 + ], + "spans": [ + { + "bbox": [ + 307, + 567, + 545, + 588 + ], + "type": "text", + "content": "[20] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 9(8):1735-1780, 1997." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 590, + 545, + 622 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 590, + 545, + 622 + ], + "spans": [ + { + "bbox": [ + 307, + 590, + 545, + 622 + ], + "type": "text", + "content": "[21] Arthur Jacot, Franck Gabriel, and Clément Hongler. Neural tangent kernel: Convergence and generalization in neural networks. arXiv preprint arXiv:1806.07572, 2018." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 624, + 545, + 677 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 624, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 307, + 624, + 545, + 677 + ], + "type": "text", + "content": "[22] Pascal Kaiser, Jan Dirk Wegner, Aurélien Lucchi, Martin Jaggi, Thomas Hofmann, and Konrad Schindler. Learning aerial image segmentation from online maps. IEEE Transactions on Geoscience and Remote Sensing, 55(11):6054-6068, 2017." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 680, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 680, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 680, + 545, + 713 + ], + "type": "text", + "content": "[23] Fanjie Kong, Bohao Huang, Kyle Bradbury, and Jordan Malof. The synthinel-1 dataset: a collection of high resolution synthetic overhead imagery for building segmentation." + } + ] + } + ], + "index": 26 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "text", + "content": "5416" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 66, + 72, + 286, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 286, + 95 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 286, + 95 + ], + "type": "text", + "content": "In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1814-1823, 2020." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 140 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 140 + ], + "type": "text", + "content": "[24] Ngan Le, Vidhiwar Singh Rathour, Kashu Yamazaki, Khoa Luu, and Marios Savvides. Deep reinforcement learning in computer vision: a comprehensive survey. Artificial Intelligence Review, pages 1-87, 2021." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 141, + 287, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 141, + 287, + 205 + ], + "spans": [ + { + "bbox": [ + 48, + 141, + 287, + 205 + ], + "type": "text", + "content": "[25] Yuxia Li, Bo Peng, Lei He, Kunlong Fan, and Ling Tong. Road segmentation of unmanned aerial vehicle remote sensing images using adversarial network with multiscale context aggregation. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 12(7):2279-2287, 2019." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 209, + 287, + 252 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 209, + 287, + 252 + ], + "spans": [ + { + "bbox": [ + 48, + 209, + 287, + 252 + ], + "type": "text", + "content": "[26] Zuoyue Li, Jan Dirk Wegner, and Aurélien Lucchi. Topological map extraction from overhead images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 1715-1724, 2019." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 254, + 287, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 254, + 287, + 308 + ], + "spans": [ + { + "bbox": [ + 48, + 254, + 287, + 308 + ], + "type": "text", + "content": "[27] Renbao Lian, Weixing Wang, Nadir Mustafa, and Liqin Huang. Road extraction methods in high-resolution remote sensing images: A comprehensive review. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 13:5489-5507, 2020." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 309, + 287, + 353 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 309, + 287, + 353 + ], + "spans": [ + { + "bbox": [ + 48, + 309, + 287, + 353 + ], + "type": "text", + "content": "[28] Jonathan Long, Evan Shelhamer, and Trevor Darrell. Fully convolutional networks for semantic segmentation. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3431-3440, 2015." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 354, + 287, + 398 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 354, + 287, + 398 + ], + "spans": [ + { + "bbox": [ + 48, + 354, + 287, + 398 + ], + "type": "text", + "content": "[29] Gellert Mattyus, Wenjie Luo, and Raquel Urtasun. Deeproadmapper: Extracting road topology from aerial images. In Proceedings of the IEEE International Conference on Computer Vision, pages 3438-3446, 2017." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 399, + 287, + 442 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 399, + 287, + 442 + ], + "spans": [ + { + "bbox": [ + 48, + 399, + 287, + 442 + ], + "type": "text", + "content": "[30] Gellert Mattyus and Raquel Urtasun. Matching adversarial networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 8024-8032, 2018." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 445, + 287, + 488 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 445, + 287, + 488 + ], + "spans": [ + { + "bbox": [ + 48, + 445, + 287, + 488 + ], + "type": "text", + "content": "[31] Gellert Mattyus, Shenlong Wang, Sanja Fidler, and Raquel Urtasun. Enhancing road maps by parsing aerial images around the world. In Proceedings of the IEEE international conference on computer vision, pages 1689-1697, 2015." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 490, + 287, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 490, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 48, + 490, + 287, + 533 + ], + "type": "text", + "content": "[32] Javier A Montoya-Zegarra, Jan D Wegner, L'ubor Ladický, and Konrad Schindler. On the evaluation of higher-order cliques for road network extraction. In 2015 Joint Urban Remote Sensing Event (JURSE), pages 1-4. IEEE, 2015." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 535, + 287, + 589 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 535, + 287, + 589 + ], + "spans": [ + { + "bbox": [ + 48, + 535, + 287, + 589 + ], + "type": "text", + "content": "[33] Philipp Moritz, Robert Nishihara, Stephanie Wang, Alexey Tumanov, Richard Liaw, Eric Liang, William Paul, Michael I Jordan, and Ion Stoica. Ray: A distributed framework for emerging ai applications. corr abs/1712.05889 (2017). arXiv preprint arXiv:1712.05889, 2017." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 590, + 287, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 590, + 287, + 643 + ], + "spans": [ + { + "bbox": [ + 48, + 590, + 287, + 643 + ], + "type": "text", + "content": "[34] Agata Mosinska, Pablo Marquez-Neila, Mateusz Kozinski, and Pascal Fua. Beyond the pixel-wise loss for topology-aware delineation. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3136–3145, 2018." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 647, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 287, + 689 + ], + "type": "text", + "content": "[35] Medhini Narasimhan, Svetlana Lazebnik, and Alexander Schwing. Out of the box: Reasoning with graph convolution nets for factual visual question answering. Advances in neural information processing systems, 31, 2018." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 692, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 692, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 692, + 287, + 713 + ], + "type": "text", + "content": "[36] Charlie Nash, Yaroslav Ganin, SM Ali Eslami, and Peter Battaglia. *Polygon: An autoregressive generative model of" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 327, + 73, + 544, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 544, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 544, + 95 + ], + "type": "text", + "content": "3d meshes. In International Conference on Machine Learning, pages 7220-7229. PMLR, 2020." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 96, + 545, + 129 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 96, + 545, + 129 + ], + "spans": [ + { + "bbox": [ + 307, + 96, + 545, + 129 + ], + "type": "text", + "content": "[37] Alejandro Newell, Kaiyu Yang, and Jia Deng. Stacked hourglass networks for human pose estimation. In European conference on computer vision, pages 483-499. Springer, 2016." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 130, + 545, + 185 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 130, + 545, + 185 + ], + "spans": [ + { + "bbox": [ + 307, + 130, + 545, + 185 + ], + "type": "text", + "content": "[38] Joachim Niemeyer, Jan Dirk Wegner, Clément Mallet, Franz Rottensteiner, and Uwe Soergel. Conditional random fields for urban scene classification with full waveform lidar data. In ISPRS Conference on Photogrammetric Image Analysis, pages 233-244. Springer, 2011." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 186, + 545, + 240 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 186, + 545, + 240 + ], + "spans": [ + { + "bbox": [ + 307, + 186, + 545, + 240 + ], + "type": "text", + "content": "[39] Aäron van den Oord, Nal Kalchbrenner, Oriol Vinyals, Lasse Espeholt, Alex Graves, and Koray Kavukcuoglu. Conditional image generation with pixelCNN decoders. In Proceedings of the 30th International Conference on Neural Information Processing Systems, pages 4797-4805, 2016." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 241, + 545, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 241, + 545, + 274 + ], + "spans": [ + { + "bbox": [ + 307, + 241, + 545, + 274 + ], + "type": "text", + "content": "[40] OpenStreetMap contributors. Planet dump retrieved from https://planet.osm.org . https://www.openstreetmap.org, 2017." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 276, + 545, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 276, + 545, + 330 + ], + "spans": [ + { + "bbox": [ + 307, + 276, + 545, + 330 + ], + "type": "text", + "content": "[41] Long Ouyang, Jeff Wu, Xu Jiang, Diogo Almeida, Carroll L Wainwright, Pamela Mishkin, Chong Zhang, Sandhini Agarwal, Katarina Slama, Alex Ray, et al. Training language models to follow instructions with human feedback. arXiv preprint arXiv:2203.02155, 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 332, + 545, + 385 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 332, + 545, + 385 + ], + "spans": [ + { + "bbox": [ + 307, + 332, + 545, + 385 + ], + "type": "text", + "content": "[42] Wamiq Para, Paul Guerrero, Tom Kelly, Leonidas J Guibas, and Peter Wonka. Generative layout modeling using constraint graphs. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 6690-6700, 2021." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 388, + 545, + 431 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 388, + 545, + 431 + ], + "spans": [ + { + "bbox": [ + 307, + 388, + 545, + 431 + ], + "type": "text", + "content": "[43] Wamiq Reyaz Para, Shariq Farooq Bhat, Paul Guerrero, Tom Kelly, Niloy Mitra, Leonidas Guibas, and Peter Wonka. Sketchgen: Generating constrained cad sketches. arXiv preprint arXiv:2106.02711, 2021." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 433, + 545, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 433, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 307, + 433, + 545, + 487 + ], + "type": "text", + "content": "[44] Tobias Pohlen, Bilal Piot, Todd Hester, Mohammad Gheshlaghi Azar, Dan Horgan, David Budden, Gabriel BarthMaron, Hado Van Hasselt, John Quan, Mel Večerík, et al. Observe and look further: Achieving consistent performance on atari. arXiv preprint arXiv:1805.11593, 2018." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 488, + 545, + 520 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 488, + 545, + 520 + ], + "spans": [ + { + "bbox": [ + 307, + 488, + 545, + 520 + ], + "type": "text", + "content": "[45] Pengda Qin, Weiran Xu, and William Yang Wang. Robust distant supervision relation extraction via deep reinforcement learning. arXiv preprint arXiv:1805.09927, 2018." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 523, + 545, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 523, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 307, + 523, + 545, + 555 + ], + "type": "text", + "content": "[46] Urs Ramer. An iterative procedure for the polygonal approximation of plane curves. Computer graphics and image processing, 1(3):244-256, 1972." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 557, + 545, + 589 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 557, + 545, + 589 + ], + "spans": [ + { + "bbox": [ + 307, + 557, + 545, + 589 + ], + "type": "text", + "content": "[47] Abdallah Saffidine, Tristan Cazenave, and Jean Méhat. Ucd: Upper confidence bound for rooted directed acyclic graphs. Knowledge-Based Systems, 34:26-33, 2012." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 590, + 545, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 590, + 545, + 644 + ], + "spans": [ + { + "bbox": [ + 307, + 590, + 545, + 644 + ], + "type": "text", + "content": "[48] Julian Schrittwieser, Ioannis Antonoglou, Thomas Hubert, Karen Simonyan, Laurent Sifre, Simon Schmitt, Arthur Guez, Edward Lockhart, Demis Hassabis, Thore Graepel, et al. Mastering atari, go, chess and shogi by planning with a learned model. Nature, 588(7839):604-609, 2020." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 647, + 545, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 647, + 545, + 679 + ], + "spans": [ + { + "bbox": [ + 307, + 647, + 545, + 679 + ], + "type": "text", + "content": "[49] John Schulman, Filip Wolski, Prafulla Dhariwal, Alec Radford, and Oleg Klimov. Proximal policy optimization algorithms. arXiv preprint arXiv:1707.06347, 2017." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "type": "text", + "content": "[50] David Silver, Hado Hasselt, Matteo Hessel, Tom Schaul, Arthur Guez, Tim Harley, Gabriel Dulac-Arnold, David Reichert, Neil Rabinowitz, Andre Barreto, et al. The predictron:" + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 750, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 750, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 750, + 315, + 757 + ], + "type": "text", + "content": "5417" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 73, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 67, + 73, + 286, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 73, + 286, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 73, + 286, + 95 + ], + "type": "text", + "content": "End-to-end learning and planning. In International Conference on Machine Learning, pages 3191-3199. PMLR, 2017." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 161 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 161 + ], + "type": "text", + "content": "[51] David Silver, Thomas Hubert, Julian Schrittwieser, Ioannis Antonoglou, Matthew Lai, Arthur Guez, Marc Lanctot, Laurent Sifre, Dharshan Kumaran, Thore Graepel, et al. A general reinforcement learning algorithm that masters chess, shogi, and go through self-play. Science, 362(6419):1140-1144, 2018." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 163, + 287, + 207 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 163, + 287, + 207 + ], + "spans": [ + { + "bbox": [ + 48, + 163, + 287, + 207 + ], + "type": "text", + "content": "[52] Suriya Singh, Anil Batra, Guan Pang, Lorenzo Torresani, Saikat Basu, Manohar Paluri, and CV Jawahar. Self-supervised feature learning for semantic segmentation of overhead imagery. In BMVC, volume 1, page 4, 2018." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 209, + 287, + 251 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 209, + 287, + 251 + ], + "spans": [ + { + "bbox": [ + 48, + 209, + 287, + 251 + ], + "type": "text", + "content": "[53] Edward J Smith, Scott Fujimoto, Adriana Romero, and David Meger. Geometrics: Exploiting geometric structure for graph-encoded objects. arXiv preprint arXiv:1901.11461, 2019." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 253, + 287, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 253, + 287, + 285 + ], + "spans": [ + { + "bbox": [ + 48, + 253, + 287, + 285 + ], + "type": "text", + "content": "[54] André Susano Pinto, Alexander Kolesnikov, Yuge Shi, Lucas Beyer, and Xiaohua Zhai. Tuning computer vision models with task rewards. arXiv e-prints, pages arXiv-2302, 2023." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 287, + 287, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 287, + 287, + 308 + ], + "spans": [ + { + "bbox": [ + 48, + 287, + 287, + 308 + ], + "type": "text", + "content": "[55] Richard S Sutton and Andrew G Barto. Reinforcement learning: An introduction. MIT press, 2018." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 310, + 287, + 364 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 310, + 287, + 364 + ], + "spans": [ + { + "bbox": [ + 48, + 310, + 287, + 364 + ], + "type": "text", + "content": "[56] Yong-Qiang Tan, Shang-Hua Gao, Xuan-Yi Li, Ming-Ming Cheng, and Bo Ren. Vecroad: Point-based iterative graph exploration for road graphs extraction. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8910-8918, 2020." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 366, + 287, + 420 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 366, + 287, + 420 + ], + "spans": [ + { + "bbox": [ + 48, + 366, + 287, + 420 + ], + "type": "text", + "content": "[57] Yuandong Tian, Jerry Ma, Qucheng Gong, Shubho Sengupta, Zhuoyuan Chen, James Pinkerton, and Larry Zitnick. Elf opengo: An analysis and open reimplementation of alphahzero. In International Conference on Machine Learning, pages 6244-6253. PMLR, 2019." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 422, + 287, + 454 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 422, + 287, + 454 + ], + "spans": [ + { + "bbox": [ + 48, + 422, + 287, + 454 + ], + "type": "text", + "content": "[58] Benigno Uria, Iain Murray, and Hugo Larochelle. A deep and tractable density estimator. In International Conference on Machine Learning, pages 467-475. PMLR, 2014." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 456, + 287, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 456, + 287, + 510 + ], + "spans": [ + { + "bbox": [ + 48, + 456, + 287, + 510 + ], + "type": "text", + "content": "[59] Aïron van den Oord, Sander Dieleman, Heiga Zen, Karen Simonyan, Oriol Vinyals, Alex Graves, Nal Kalchbrenner, Andrew Senior, and Koray Kavukcuoglu. Wavenet: A generative model for raw audio. In 9th ISCA Speech Synthesis Workshop, pages 125-125, 2016." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 512, + 287, + 544 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 512, + 287, + 544 + ], + "spans": [ + { + "bbox": [ + 48, + 512, + 287, + 544 + ], + "type": "text", + "content": "[60] Adam Van Etten, Dave Lindenbaum, and Todd M Bacastow. Spacenet: A remote sensing dataset and challenge series. arXiv preprint arXiv:1807.01232, 2018." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 546, + 287, + 589 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 546, + 287, + 589 + ], + "spans": [ + { + "bbox": [ + 48, + 546, + 287, + 589 + ], + "type": "text", + "content": "[61] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Advances in neural information processing systems, pages 5998-6008, 2017." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 591, + 287, + 612 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 591, + 287, + 612 + ], + "spans": [ + { + "bbox": [ + 48, + 591, + 287, + 612 + ], + "type": "text", + "content": "[62] Oriol Vinyals, Meire Fortunato, and Navdeep Jaitly. Pointer networks. arXiv preprint arXiv:1506.03134, 2015." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 614, + 287, + 667 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 614, + 287, + 667 + ], + "spans": [ + { + "bbox": [ + 48, + 614, + 287, + 667 + ], + "type": "text", + "content": "[63] Nanyang Wang, Yinda Zhang, Zhuwen Li, Yanwei Fu, Wei Liu, and Yu-Gang Jiang. Pixel2mesh: Generating 3d mesh models from single rgb images. In Proceedings of the European Conference on Computer Vision (ECCV), pages 52-67, 2018." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 670, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 287, + 712 + ], + "type": "text", + "content": "[64] Shenlong Wang, Min Bai, Gellert Mattyus, Hang Chu, Wenjie Luo, Bin Yang, Justin Liang, Joel Cheverie, Sanja Fidler, and Raquel Urtasun. Toronto: Seeing the world with a million eyes. arXiv preprint arXiv:1612.00423, 2016." + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 364 + ], + "type": "list", + "angle": 0, + "index": 23, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 117 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 117 + ], + "type": "text", + "content": "[65] Jan D Wegner, Javier A Montoya-Zegarra, and Konrad Schindler. A higher-order crf model for road network extraction. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1698-1705, 2013." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 119, + 545, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 119, + 545, + 161 + ], + "spans": [ + { + "bbox": [ + 307, + 119, + 545, + 161 + ], + "type": "text", + "content": "[66] Christian Wiedemann, Christian Heipke, Helmut Mayer, and Olivier Jamet. Empirical evaluation of automatically extracted road axes. Empirical evaluation techniques in computer vision, 12:172-187, 1998." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 163, + 545, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 163, + 545, + 206 + ], + "spans": [ + { + "bbox": [ + 307, + 163, + 545, + 206 + ], + "type": "text", + "content": "[67] Danfei Xu, Yuke Zhu, Christopher B Choy, and Li Fei-Fei. Scene graph generation by iterative message passing. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5410-5419, 2017." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 209, + 545, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 209, + 545, + 239 + ], + "spans": [ + { + "bbox": [ + 307, + 209, + 545, + 239 + ], + "type": "text", + "content": "[68] Jingtao Xu, Yali Li, and Shengjin Wang. Adazoom: Adaptive zoom network for multi-scale object detection in large scenes. arXiv preprint arXiv:2106.10409, 2021." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 242, + 545, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 242, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 307, + 242, + 545, + 285 + ], + "type": "text", + "content": "[69] Zhenhua Xu, Yuxuan Liu, Lu Gan, Yuxiang Sun, Xinyu Wu, Ming Liu, and Lujia Wang. Rngdet: Road network graph detection by transformer in aerial images. IEEE Transactions on Geoscience and Remote Sensing, 60:1-12, 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 287, + 545, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 287, + 545, + 330 + ], + "spans": [ + { + "bbox": [ + 307, + 287, + 545, + 330 + ], + "type": "text", + "content": "[70] Jianwei Yang, Jiasen Lu, Stefan Lee, Dhruv Batra, and Devi Parikh. Graph r-cnn for scene graph generation. In Proceedings of the European conference on computer vision (ECCV), pages 670-685, 2018." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 331, + 545, + 364 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 331, + 545, + 364 + ], + "spans": [ + { + "bbox": [ + 307, + 331, + 545, + 364 + ], + "type": "text", + "content": "[71] Weirui Ye, Shaohuai Liu, Thanard Kurutach, Pieter Abbeel, and Yang Gao. Mastering atari games with limited data. arXiv preprint arXiv:2111.00210, 2021." + } + ] + } + ], + "index": 22 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 750, + 315, + 758 + ], + "type": "text", + "content": "5418" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/1fb06bbc-ee8a-4da1-8280-e317a61d1b94_content_list.json b/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/1fb06bbc-ee8a-4da1-8280-e317a61d1b94_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..8e214f0b2734fb75d88542f80842420d93c5f1c6 --- /dev/null +++ b/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/1fb06bbc-ee8a-4da1-8280-e317a61d1b94_content_list.json @@ -0,0 +1,2144 @@ +[ + { + "type": "text", + "text": "MatrixCity: A Large-scale City Dataset for City-scale Neural Rendering and Beyond", + "text_level": 1, + "bbox": [ + 259, + 130, + 709, + 175 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Yixuan Li $^{1*}$ , Lihan Jiang $^{2*}$ , Linning Xu $^{1}$ , Yuanbo Xiangli $^{1}$", + "bbox": [ + 245, + 202, + 720, + 222 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Zhenzhi Wang $^{1}$ , Dahua Lin $^{1,2}$ , Bo Dai $^{2}$", + "bbox": [ + 320, + 223, + 648, + 241 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1 The Chinese University of Hong Kong 2 Shanghai AI Laboratory", + "bbox": [ + 212, + 241, + 756, + 260 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "ly122@ie.cuhk.edu.hk jianglihan@pjlab.org.cn", + "bbox": [ + 287, + 262, + 679, + 276 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{x1020,xy019,wz122,dhlin}@ie.cuhk.edu.hk daibo@pjlab.org.cn", + "bbox": [ + 223, + 279, + 745, + 294 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/ffc577d43c3d9084dbd9a57a6066482c51bba44cfdb73cc74a65bea46431ec83.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 124, + 320, + 325, + 446 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/4488920490e2240752b12acb8ed42149b4da4260f83f2f002f1647b5d3093a94.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 326, + 321, + 454, + 446 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/bf1f3b5c8849b58f1e42d402fb36bd3842ec365b1df62de3470877236224bcac.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 454, + 321, + 586, + 446 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/63838a31527cccd3037f8978c7aaa598a228d606b8f3005d5823c28cdbfa7ec4.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 586, + 321, + 717, + 446 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/ea45c4e15e8d633a7e2e1d49923ffad2e08d0aeda85a81482a6d9c634db38c48.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 718, + 321, + 849, + 446 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/31b506e8013a3500158603eb66b36adb7dfe8aca35cba258ae149d076bc7edd9.jpg", + "image_caption": [ + "Figure 1: An illustration of MatrixCity dataset's small city. a) We collected high-quality large-scale city scene images for a city-scale neural rendering benchmark from Unreal Engine 5, capturing various city environments from multiple viewing angles. b) Our flexible environment control can collect data under dynamic environmental factors such as varying lighting and weather conditions. c) Our developed platform also facilitates the extraction of additional properties, including depth maps and normal maps. These features open a wide range of opportunities for future research in city-scale neural rendering." + ], + "image_footnote": [], + "bbox": [ + 127, + 450, + 310, + 568 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/3382002608ea0464ffb32f81ab742c7cc9629ff8a43da3f4c8aee5205d33d9ed.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 310, + 450, + 504, + 568 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/015b38a5c12159dd47d74857989e246806437689c5f873f1200d26bea0064c2f.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 504, + 450, + 730, + 568 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/5715816fea391e7bc1118e82cb904304b5c5212498bacfc70bd24d68dd1b55f1.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 728, + 450, + 849, + 568 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 667, + 313, + 684 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Neural radiance fields (NeRF) and its subsequent variants have led to remarkable progress in neural rendering. While most of recent neural rendering works focus on objects and small-scale scenes, developing neural rendering methods for city-scale scenes is of great potential in many real-world applications. However, this line of research is impeded by the absence of a comprehensive and high-quality dataset, yet collecting such a dataset over real city-scale scenes is costly, sensitive, and technically infeasible. To this end, we build a large-scale, comprehensive, and high-quality synthetic dataset for city-scale neural rendering researches. Leveraging the Unreal Engine 5 City Sample project, we developed a pipeline to easily collect aerial", + "bbox": [ + 75, + 704, + 472, + 902 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "and street city views, accompanied by ground-truth camera poses and a range of additional data modalities. Flexible controls on environmental factors like light, weather, human and car crowd are also available in our pipeline, supporting the need of various tasks covering city-scale neural rendering and beyond. The resulting pilot dataset, MatrixCity, contains 67k aerial images and 452k street images from two city maps of total size $28km^2$ . On top of MatrixCity, a thorough benchmark is also conducted, which not only reveals unique challenges of the task of city-scale neural rendering, but also highlights potential improvements for future works. The dataset and code will be publicly available at the project page: https://city-super.github.io/matrixcity/.", + "bbox": [ + 496, + 669, + 893, + 867 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "3205", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 89, + 209, + 104 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Realistic rendering of city-scale scenes is a crucial component of many real-world applications, including aerial surveying, virtual reality, film production, and gaming. While NeRF [22] has made notable advancements in rendering objects and small-scale scenes, only a few early attempts [30, 33, 37] have sought to extend NeRF and its variants to larger city-scale scenes. Due to the paucity of benchmark dataset, the complexity and challenges of city-scale neural rendering have not been thoroughly investigated.", + "bbox": [ + 75, + 114, + 468, + 251 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Collecting a comprehensive and high-quality city-scale dataset in real-world is time consuming and resource intensive, and can be technically infeasible. Moreover, it is also impossible to control environmental factors, such as lighting conditions, weather patterns, and the presence of transient objects like pedestrians and vehicles. Thus, existing urban datasets [17, 33, 8] are limited to a few independent scenes rather than comprehensive city maps, failing to capture the diversity of urban environments. Furthermore, existing datasets often feature monotonous viewing angles, such as street-level [30] or aerial imagery [17, 33, 8], leading to partial city modeling with incomplete building geometries and ground-level details. Even if sufficient real-world city data is collected, legal or commercial issues can limit its accessibility, e.g., Block-NeRF dataset [30] only provides access to $1\\mathrm{km}$ street data, and UrbanScene3D dataset [17] offers only two real-world scenarios. Such restrictions significantly hinder the ability of researchers to advance the field of city-scale neural rendering.", + "bbox": [ + 75, + 251, + 470, + 537 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "This paper presents MatrixCity, a comprehensive and high-quality synthetic dataset to support the research of city-scale neural rendering as well as other extended tasks. Specifically, MatrixCity has several distinguished features: 1) High Quality. It is built in the City Sample project $^{1}$ of Unreal Engine $5^{2}$ with advanced graphic technologies which allows for the public release of rendered images. As shown in Figure 1, this engine offers rich city details of fine-grained textures and geometries from its photo-realistic rendering quality with realistic lighting, shadow effects, and accurate ground-truth camera poses. 2) Scale and Diversity. To create the MatrixCity dataset, we developed a plugin that can automatically capture data from the map of two cities provided by Unreal Engine 5, resulting in 172k and 347k images, respectively. These images cover areas equivalent to $2.7\\mathrm{km}^2$ and $25.3\\mathrm{km}^2$ in the real-world. The captured regions showcase a broad spectrum of urban landscapes, mirroring the complexity and heterogeneity of genuine cities. 3) Controllable Environments. Our developed plugin provides flexible control over a range of environmental factors", + "bbox": [ + 75, + 537, + 470, + 840 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "that are uncontrollable in the real world, including lighting, weather, and human and car crowds. By decoupling these various factors, we are able to provide corresponding data that can support in-depth research of city-scale neural rendering. 4) Multiple Properties. The plugin can also customize data collection trajectories, and extract multiple ground-truth components, including depth, normal and decomposed components of reflectance (e.g. diffuse, specular, metallic, etc.). Such advanced feature enables researchers to not only perform a range of city-scale neural rendering tasks under varying conditions but also supports other extended tasks, for example depth estimation and inverse rendering.", + "bbox": [ + 500, + 90, + 890, + 286 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Our benchmark study demonstrates the value of Matrix-City in advancing city-scale neural rendering researches. We experiment with several state-of-the-art neural rendering methods to conduct empirical analyses first on aerial and street data respectively, then on the fused data from both modes. Preliminary results indicate that even with these advanced methods, city-scale neural rendering is still a far-reaching goal. Specifically, we identified several challenges: 1) In aerial data, learning high-rise city regions poses a greater challenge than low-rise/ground areas due to complex building structures and occlusion; 2) Street data contains significantly more details than aerial data, which raises challenges for model capacity. Although block-size aerial data modeling is feasible, modeling street data with the same size may be more difficult; 3) The view direction and level of details varied significantly between the two modes of data, making it difficult to train them together; 4) Current models generally performed poorly on smaller objects with more details and reflective buildings in urban scenes. These findings present significant opportunities to advance research in city-scale neural rendering.", + "bbox": [ + 498, + 287, + 892, + 603 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In summary, our contributions are as follows:", + "bbox": [ + 517, + 604, + 818, + 619 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We constructed a large-scale, high-quality dataset for city-scale neural rendering, named MatrixCity. This dataset emphasizes attributes pivotal to city-scale scenes, encompassing elements like dynamic interactions and lighting conditions. MatrixCity contains both aerial and street-level images of complete city maps with extra depth, normal, and decomposed BRDF materials capable of supporting multiple tasks.", + "- We developed a plugin that leverages Unreal Engine 5 for automatic high-quality city data collection, allowing researchers to flexibly control lighting, weather, and transient objects. The plugin simplifies data collection for different task settings, making it a valuable tool for the community where users can build up advanced datasets as demanded.", + "- We conducted extensive studies on the MatrixCity dataset, which revealed some key challenges of city" + ], + "bbox": [ + 517, + 626, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_footnote", + "text": "1https://www.unrealengine.com/marketplace/en-US/product/city-sample", + "bbox": [ + 76, + 849, + 439, + 875 + ], + "page_idx": 1 + }, + { + "type": "page_footnote", + "text": "$^{2}$ https://www.unrealengine.com/", + "bbox": [ + 96, + 875, + 269, + 887 + ], + "page_idx": 1 + }, + { + "type": "page_footnote", + "text": "3https://www.unrealengine.com/en-US/eula/unreal", + "bbox": [ + 96, + 887, + 364, + 898 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "3206", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "scale neural rendering, and hopefully facilitate future research in this area.", + "bbox": [ + 109, + 90, + 467, + 119 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2. Related work", + "text_level": 1, + "bbox": [ + 76, + 136, + 212, + 152 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.1. 3D Neural Representation at City Scale", + "text_level": 1, + "bbox": [ + 76, + 161, + 413, + 178 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "City-scale reconstruction has been studied for decades. Previous methods for representing geometry of a city mainly relied on raw point clouds acquired through either structure-from-motion [1] or Lidar sensors [12]. Recently, with the emergence of Neural Radiance Fields (NeRF) [22], novel view synthesis has become more efficient and effective. Numerous methods in this direction have further improved the speed [18, 28, 10, 23, 7] and accuracy [40, 3, 4] of reconstruction. NeRF is also used in a wide range of applications beyond novel view synthesis, such as inverse rendering [5, 27, 42, 26], surface reconstruction [34, 36, 2, 38] or HDR synthesis [11, 14, 21]. Although these methods demonstrate acceptable performance with small objects, grappling with urban scenes remains a significant challenge due to the limited representation capability of NeRF.", + "bbox": [ + 76, + 185, + 467, + 411 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Based on these observations, recent methods were proposed for reconstructing radiance fields in urban-scale scenes. NeRF-W [20] captured per-image appearance variations and separated the entire scene into static and transient components, enabling the modeling of unstructured collections of in-the-wild photographs. Block-NeRF [30] extended NeRF-W [20] to model an neighborhood of San Francisco by dividing up urban environments into individually small Block-NeRFs. Mega-NeRF [33] also adopted the advantages of NeRF-W [20] and Block-NeRF [30] by first decomposing large-scale fly-view scenes into small spatial cells and then training these cells in parallel. Urban Radiance Fields [25] synthesized novel RGB images and extracted 3D surfaces from a combination of panoramicas and Lidar inputs in the urban environments. BungeeNeRF [37] introduced progressive modeling with multi-level supervision to handle city-scale data with varying levels of detail. Despite the progress made by the aforementioned methods [20, 30, 33, 25, 37], there is no unified dataset for evaluating these methods due to their varying settings. Significant challenge still remains in the city reconstruction problem, particularly in integrating aerial data and street-level data with varying levels of detail.", + "bbox": [ + 76, + 412, + 467, + 758 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. NeRF-based Datasets and Benchmarks", + "text_level": 1, + "bbox": [ + 76, + 770, + 411, + 786 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Several benchmarks based on NeRF are proposed in the recent two years, which focus on the effective and better reconstruction of single objects [22, 18, 13], indoor scenes [9], or outdoor unbounded scenes [4, 15]. While there have been some good attempts to collect high-quality large-scale datasets using high-precision acquisition equipment [8, 17, 30, 19] as shown in Table 1, the high acquisition", + "bbox": [ + 76, + 794, + 467, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "costs limit their size and scale. Some datasets are limited to only a few independent scenes that are far from urban-scale or are not fully open-source due to privacy and commercial reasons. For instance, Mill 19 dataset [33] only includes two suburban-like scenes, and the Quak 6D [8] and OMMO [19] datasets focus on a limited number of independent scenes that are not city-scale. Waymo Block-NeRF [30] dataset only grants access to 100 seconds of driving data and Urban Scene3D dataset [17] only releases two real-world scenarios. Additionally, existing real-world datasets commonly provide only one type of image data, such as street-level or aerial imagery, which makes modeling buildings incomplete [17, 19]. Collecting real data in outdoor scenes poses significant challenges due to difficulties in controlling environmental factors such as pedestrian movement, weather, and lighting. As a result, a standard and comprehensive benchmark for city-scale neural rendering has not yet been established. Existing outdoor NeRF-based benchmarks like OMMO [19] are too trivial to explore and analyze the urban implicit scene representation. To address these issues, we developed a plugin in Unreal Engine 5 to easily collect aerial and street city data with ground-truth camera poses. We built a city-scale and multitasking dataset that includes both fly-view and street-view images and propose a new city-scale benchmark for neural rendering. We also provided a detailed analysis of the challenges and opportunities of NeRF in urban environments.", + "bbox": [ + 496, + 90, + 890, + 498 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. MatrixCity Dataset", + "text_level": 1, + "bbox": [ + 500, + 508, + 686, + 526 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The MatrixCity dataset aims to introduce a new challenging benchmark to the field of city-scale neural rendering by providing comprehensive city maps consisting of both aerial and street-level data. In addition to RGB images, we also offer normal, depth, and decomposed reflectance properties to support other tasks. Moreover, we can flexibly control environmental factors, including light direction and intensity, fog density, and human or vehicle crowding, to enable simulating real-world dynamic situations. Sec 3.1 describes our data construction procedure. Sec 3.2 and 3.3 provide detailed statistics and characteristics of this dataset.", + "bbox": [ + 496, + 535, + 890, + 702 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Dataset Construction", + "text_level": 1, + "bbox": [ + 500, + 708, + 697, + 723 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "City Data Collection. Densely captured 2D images with sufficient multi-view supervision are required to learn a faithful scene geometry, especially for large city scenes. Collecting a sufficient amount of data in Unreal Engine 5 for city scenes is a complex process that requires adjusting camera trajectories to capture specific viewpoints. Although the Unreal Engine 5 offers a movie render queue plugin for high-quality image rendering, it can be time-consuming and inflexible to manually set up the position, rotation, and frame number of key points. For urban settings, it is not practical to manually set camera trajectories", + "bbox": [ + 496, + 734, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "3207", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/dba1b9a66b17b62fe7ae27698d59970b39418182f6f1f7d4601c45c036acac6d.jpg", + "image_caption": [ + "(a) Aerial block splits" + ], + "image_footnote": [], + "bbox": [ + 122, + 90, + 346, + 227 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/c0dd721ca974d0114370666b42366b01b072db2d002ca382c15a372bc817864a.jpg", + "image_caption": [ + "(b) Aerial trajectory in block 4", + "Figure 2: Illustration of data collection in the small city in Unreal Engine 5. (a) Aerial block split for the entire small city; (b&c) Camera aerial and street trajectory of block 4 (visualized in bird-eye views) used in our plugin for data collection." + ], + "image_footnote": [], + "bbox": [ + 370, + 93, + 599, + 227 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/a96c06da27a4398104f48b26fe15eed2cc98e434f62112eb732c6819bb26dee7.jpg", + "image_caption": [ + "(c) Street trajectory in block 4" + ], + "image_footnote": [], + "bbox": [ + 625, + 93, + 851, + 224 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "in a city-scale environment. To address this, we developed a plugin that automatically generates camera trajectories, reducing the need for manual annotation and increasing the efficiency of data collection. Camera trajectories generated by our plugins can be rendered in any Unreal Engine 5 scenes.", + "bbox": [ + 75, + 337, + 468, + 428 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "For aerial-view collection, we divide the city map into 10 blocks based on building heights (Figure 2 (a)) to better capture the building details. We provide the height of every collected block in the supplementary material. Note that current neural scene representations are generally suitable for bounded scenes, where scenes with large variation in height may cast great difficulty for accurate ray sampling. We then generate trajectories using the input of camera height and the four vertices' coordinates of the corresponding block (Figure 2 (b)) Our plugin puts four cameras at each capturing location, with each camera rotating $90^{\\circ}$ apart from each other in the yaw direction and identical pitch values. The pitch value for the floor area is $-45^{\\circ}$ , while it is $-60^{\\circ}$ for high-rise area as there are more occlusions at higher levels.", + "bbox": [ + 75, + 430, + 470, + 656 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "For street-view data collection, we manually annotate the start and end points of each road and use them as inputs to generate straight-line trajectories with our plugin. We position six perspective cameras at each capturing location to render a cube map, providing a comprehensive view of the surroundings. Note that the cube map can be naturally transformed into panorama images, which are suitable for capturing the street views as much as possible with limited camera positions. Figure 2 (c) shows the resulting street-level trajectories for a specific block. Our plugin saves the generated camera trajectories as sequence assets of Unreal Engine, which can be easily reused to render images with different environmental settings. We will enhance our plugin to support more complex camera trajectories in the future, enabling us to generate even higher quality city-scale data. Note that we adapt auto-exposure to collect data. If", + "bbox": [ + 75, + 659, + 470, + 900 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "we use the same fixed exposure for two types of data, the street views will be under-exposed while the aerial views will be over-exposed. HDR images will be included in the future.", + "bbox": [ + 496, + 337, + 892, + 397 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Quality Control. To build a high-quality dataset for city-scale neural rendering, we utilize several mechanisms to ensure that the rendered images are of high quality and that the camera poses are accurate. Rather than using the more efficient real-time rendering pipeline, which often produces flickering images, we use the movie render queue plugin to render images with movie-level standards. Additionally, we set the Engine Scalability Settings to the best, turn off the motion blur and use anti-aliasing during the rendering process to achieve the highest possible image quality. We inspect the images thoroughly after rendering to remove any aerial views that look outside the map boundaries and ensure that there are no object clippings. Unreal Engine 5 provides ground-truth camera poses, which we have further verified through additional experiments to ensure their accuracy. Even with a small set of street data, training the MipNeRF-360 [4] model yields almost perfect novel view synthesis results, as demonstrated in Figure 6. This confirms the accurate annotation of our camera poses. Overall, by adopting these mechanisms, we ensure that the Matrix-City dataset provides high-quality images with precise camera poses, which is crucial for city-scale neural rendering research. Without considering noises like inaccurate pose and motion blur, we intend to gain more insights about the intrinsic challenges of city scenes since isolating these noises from real data is generally infeasible.", + "bbox": [ + 496, + 407, + 893, + 800 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Dynamic Environments. The City Sample project of Unreal Engine 5 provides a plethora of powerful functions that allow for the creation of dynamic city scenes. As shown in Figure 1, we have the ability to control the presence of moving people and cars in the scene, adding to the realism of the environment. Additionally, we can quantitatively adjust", + "bbox": [ + 496, + 809, + 893, + 902 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "3208", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/1aaf2d2e8e3bdd8980447958fc7762a6d08ceb2cbf9ca763f4d66dc3c975311e.jpg", + "image_caption": [ + "Figure 3: Illustration of controlling dynamic environment factors in Unreal Engine 5 such as illumination (a), fog density (b) and decomposed reflectance (c)." + ], + "image_footnote": [], + "bbox": [ + 78, + 88, + 895, + 305 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "the angle and intensity of the lighting to emulate the natural changes in light throughout a day, as demonstrated in Figure 3(a). We can also control the amount of fog in a scene, as shown in Figure 3(b), providing another quantitative tool for enhancing realism. Taken together, these functions allow for the simulation of almost all basic dynamic situations found in the real world. In addition, general camera noises like motion blur and defocus blur shown in Figure 4 can be simulated in Unreal Engine. Such varying lighting, weather conditions, moving objects and camera noises will lead to more realistic and accurate city-scale neural rendering.", + "bbox": [ + 75, + 387, + 472, + 553 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Multiple Properties. Figure 1 (c) and Figure 3 (c) illustrates the various intermediate products generated by Unreal Engine during the rendering process, including depth, normal, and decomposed components (diffuse, specular, metallic, and roughness). These attributes are especially important for studies on inverse rendering and semantic analysis, which are popular for city scene analysis. Our plugin offers the ability to extract these properties without incurring any additional costs, which can be prohibitively expensive to obtain in real-world scenarios.", + "bbox": [ + 75, + 559, + 472, + 710 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.2. Dataset Statistics", + "text_level": 1, + "bbox": [ + 76, + 724, + 246, + 739 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The MatrixCity dataset comprises two scenes from the City Sample project: Small City covering an area of $2.7km^2$ and Big City spanning $25.3km^2$ . In total, we collect 67k aerial images and 452k street-level images to ensure comprehensive coverage. As shown in Table 1, many of current datasets [17, 8, 19] do not offer the dense image captures of the whole city but small-size independent scenes. Although Waymo Block-NeRF [30] dataset densely collects an area of approximately $960m \\times 570m$ , it only contains street data and results in the reconstructed buildings incom", + "bbox": [ + 75, + 750, + 472, + 902 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "plete. All the existing datasets do not have quantitatively controllable environments including light, weather and human and car crowds, nor multiple properties like normal, depth, the decomposed reflectance components, etc, which restricts the in-depth study of city-scale neural rendering in dynamic scenes and other extension tasks. KITTI-360 [16], NuScenes [6], Waymo Open [29] are not designed for neural rendering purposes and only provide limited camera viewpoints.", + "bbox": [ + 496, + 387, + 893, + 523 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/b5e3952916ea6f7b44b92747901e77d66c457413e12a681ae6ca37c745ec2cc0.jpg", + "image_caption": [ + "Figure 4: Examples of camera motion blur and defocus blur." + ], + "image_footnote": [], + "bbox": [ + 504, + 536, + 893, + 636 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.3. Dataset Characteristics", + "text_level": 1, + "bbox": [ + 500, + 704, + 718, + 719 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "High Quality. For constructing MatrixCity dataset, we use the City Sample project and the movie-level plugin named movie render queue of the Unreal Engine 5 which is demonstrated to reproduce The Matrix Awakens. Unlike games, the rendering process is not real-time and costs huge computations with pre-defined camera poses. Such movie-level rendering quality enables the collection of realistic city-scale data similar to the real world with fully dynamic environment factors. Vigorous quality control is performed during its collection phase.", + "bbox": [ + 496, + 729, + 893, + 882 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Large-scale and Diversity. The City Sample project of Un", + "bbox": [ + 500, + 885, + 890, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "3209", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/7d1ec882faa43eea7db01784cf3cc2b69c3077894122d603fa5f2bc6689b3caf.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Dataset#ImagesLevelTypesSourceLightingHuman/CarWeatherD-Reflectance
UrbanScene3D [17]128KSceneAerialSynthetic & RealXXXX
Quad 6K [8]5.1KSceneAerialRealXXXX
Mill 19 [33]3.6KSceneAerialRealXXXX
Waymo Block-NeRF [30]12KCityStreetReal✓XXX
OMMO [19]14.7KSceneAerialReal✓XXX
KITTI-360 [16]300KCityStreetRealX✓XX
NuScenes [6]1.4MCityStreetReal✓✓✓X
Waymo Open [29]1MCityStreetReal✓✓✓X
Ours519kCityAerial+StreetSynthetic✓✓✓✓
", + "bbox": [ + 81, + 88, + 893, + 246 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/1454fe48ebdc391575187d6e79f1a05deb4d3acf2345dd0e28f61a67392c5cb2.jpg", + "table_caption": [ + "Table 1: Comparison of statistics and properties between our MatrixCity dataset with previous datasets." + ], + "table_footnote": [], + "table_body": "
BlockNeRF [22]DVGO [28]TensoRF [7]Instant-NGP [23]MipNeRF-360 [4]Average Height
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
Block_A23.150.5610.64925.040.6770.52025.960.7200.46227.210.7930.37626.640.7720.406150
Block_B22.940.6130.48522.720.6490.46324.950.7760.32625.450.8260.27124.800.7650.352432
Block_C22.150.5900.52721.390.6490.47524.110.7540.37023.210.7880.31124.200.7590.365419
Block_D23.090.5700.54824.140.6560.48624.990.7120.41626.240.7850.33826.450.7900.338250
Block_E23.530.6120.53424.740.7040.46725.660.7490.40826.360.8070.33526.540.8110.338200
Overall22.970.5890.54823.610.6670.48225.130.7620.39625.690.8000.32625.730.7790.360279
", + "bbox": [ + 81, + 286, + 890, + 377 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2: Performance comparison of representative neural rendering methods on the aerial data of our MatrixCity benchmark.", + "bbox": [ + 76, + 387, + 890, + 402 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "real Engine 5 includes two cities with a large-scale coverage, which captures varying buildings, pedestrians, signs, vehicles, and lighting conditions, resulting in more diverse and realistic outdoor scenes that are representative of real-world cities. This ensures that researchers have access to a broad range of data to train their models on, leading to more accurate and effective city-scale neural rendering.", + "bbox": [ + 75, + 429, + 470, + 536 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Controllable Environments. Unlike the real world data, we could control the lighting angle and intensity, the density and height of fog, and the density of flow of pedestrians and vehicles in a fine-grained manner. This flexibility enables us to generate dynamic scenarios of city scenes that would be difficult to capture in real-world data. This level of control over the environment allows for more detailed exploration of how different factors influence the training process of city-scale neural rendering.", + "bbox": [ + 75, + 546, + 468, + 681 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Multiple Properties. Our developed plugin is able to extract additional information such as depth, normal and the decomposed reflectance components with minimum extra cost in Unreal Engine 5. This information supports additional tasks such as depth estimation, inverse rendering, which cannot be supported by real-world data without excessive labor.", + "bbox": [ + 75, + 691, + 468, + 797 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Applications. By exploring neural rendering models on MatrixCity, we can transfer the algorithms to real-world urban scenes, which can generate scene for games, virtual reality, automatic driving, and so on. The rendered scenes can also make the interactions with digital humans possible in the metaverse.", + "bbox": [ + 75, + 809, + 470, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 500, + 428, + 632, + 445 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this section, we mainly investigate the quality of reconstruction and novel view rendering, and reveal the challenges of adapting existing SOTA methods on this task. Additional studies (e.g., dynamics scenes, lighting control, etc.) are provided in the supplementary material.", + "bbox": [ + 496, + 454, + 890, + 530 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Datasets and Metrics.", + "text_level": 1, + "bbox": [ + 500, + 544, + 702, + 559 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "MatrixCity benchmark. The MatrixCity dataset contains two city maps: Small City and Big City. According to the common practice in surveying and mapping that adjacent images should have an overlap of $70\\% - 80\\%$ , we set a camera capture location every $40\\mathrm{m}$ for aerial data collection and $5\\mathrm{m}$ for street data collection. Small City includes 6k aerial images and 30k street-level images, while Big City has $60\\mathrm{k}$ aerial images and $286\\mathrm{k}$ street-level images. Note that we remove the aerial images that look outside the map boundary manually. Also, we remove the street images that look straight down following nerfstudio [31], which crops the bottom $20\\%$ of the 360 images to reduce useless information. The ratio of training set to testing set is 8:1. To ensure both completeness of training perspectives and generalization ability in testing, test set is collected separately with no location overlap with the training set. For aerial data, the yaw direction randoms from $0^{\\circ}$ to $360^{\\circ}$ and the pitch direction randoms from $-60^{\\circ}$ to $-45^{\\circ}$ , and every camera location captures 1 image. For street data, the yaw direction randoms from $0^{\\circ}$ to $90^{\\circ}$ and every camera location captures 5 images, whose pitch and roll direction keep the same with the training set. Since the street data", + "bbox": [ + 496, + 568, + 893, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "3210", + "bbox": [ + 482, + 944, + 516, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/a2d6f57608e675e78379d5ead5c87581a9d97f8f795ddb315597e45ffc6376a5.jpg", + "image_caption": [ + "(a)" + ], + "image_footnote": [], + "bbox": [ + 80, + 104, + 233, + 157 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/7efc69beb5066bf13d8c1f8f7fe8ef82267b6132cd0d525e4f0dbc72982e441b.jpg", + "image_caption": [ + "(b)" + ], + "image_footnote": [], + "bbox": [ + 243, + 104, + 395, + 157 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/52d526dd38275ecbdd4c3aed1b1558d91cc8aa4e8b0e25e93013c4ee4dcdc618.jpg", + "image_caption": [ + "(c)" + ], + "image_footnote": [], + "bbox": [ + 406, + 104, + 560, + 157 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/ac7c6bf44ffb6fff2627945aaedb66d3dc74c32eda2de31519d1ce08e2c511bd.jpg", + "image_caption": [ + "(d)" + ], + "image_footnote": [], + "bbox": [ + 570, + 104, + 723, + 157 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1813f822a44f559611da00862e23003591e3b19d2d7d677e02f375d425ae54a6.jpg", + "image_caption": [ + "(e)" + ], + "image_footnote": [], + "bbox": [ + 735, + 104, + 888, + 157 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/173e59d390a78f1d9d69cb754a988b12682306dbcb8752b37003019d37878b04.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 80, + 162, + 233, + 217 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/3baee1e69fd85e034b3f8d235b8afe23a98a5c7b00d5ed17b164e76207319149.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 243, + 162, + 395, + 217 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/cc3f57e98e3b2ad5c6d5ed1bff31cdc9a59a46609d6e78543b25f8125a4c8643.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 406, + 164, + 560, + 218 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/b3e25edfb77ad005a815d3bf031608e309d278bac5adca17224a7a06f133aecd.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 570, + 162, + 723, + 217 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/a1a50fd0d26136aadc0a924e8463884a11b3eb1ac58e3d9ee4f1481e945d51c3.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 735, + 162, + 888, + 217 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/79b2dc24e1d250ceb72897e93fc73767d98f70a954ef5d6ac09628a55175b33c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 80, + 222, + 233, + 276 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/4c310fb0e91d88429ca7c324eaa847d61b0839f0a8ea58ddd9733c19a444879f.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 243, + 222, + 395, + 276 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/66c6eb2cbb21e8630657c63ca89d6a11c9e39e4d72015cebbdcbf426c5f398db.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 406, + 222, + 560, + 276 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/db4e6e40e4198f57cb5d9752cd4c7c7eb6e97c4971e0aed54ef5e73431321aa5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 570, + 220, + 723, + 275 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1711fba39d6a4b55cf609d004aec26cdeca75f69e9cb812dc4a019a37afc0d5f.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 735, + 220, + 888, + 275 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/a37d26131b6638166dbe2630e902b341cbf9e8e5ac795846ee50f50214112cec.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 80, + 281, + 233, + 334 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/a506bdf0e33bf58c600353d7628583392f73bf814ee68f686c56a4f9fa53549a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 243, + 281, + 395, + 334 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/9a9aee706fc4a8b55126bbf59915f49eace32ae5a8dcf0f9a30e3a6ce3a7a919.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 406, + 280, + 560, + 333 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1ae01777f307d7c415f7fbf05cf39cf67bcbc11497c54b0d00833a6d9238f4af.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 570, + 280, + 723, + 333 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/eb7cf7b07977e8bff84813ccf5a2da69805288033ee1e79c1124a6064b1335ef.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 735, + 280, + 888, + 333 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/f415401d89c9534bfebd6ae89ca9ebd3f3e1666c1d1dc20125047f1cacfc7e52.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 80, + 340, + 233, + 393 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/ffd2c28d94582a153dc45750b939397ee5e831f8be52f406923c154e6390bd06.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 243, + 340, + 395, + 393 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/df5f8b3f1dd503685f0ca65e6fe4d272478bef06c5001516c64b570b58ba8803.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 406, + 340, + 560, + 393 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/9e574bf958c0afa6d5a39fb992bbbe7ebc49de439a64ea0a8cf01bf0ffb99881.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 570, + 339, + 723, + 392 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/579f264aa39dcd92dec537a98d9a4776ecb4942167873289564431404306e9ae.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 735, + 339, + 888, + 392 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1b5d6d54acaa2e4b773c3421b05c284fd627d498991eee280e06e4aff32968ff.jpg", + "image_caption": [ + "Figure 5: Visualization of novel view synthesis results of previous representative large-scale neural rendering methods on the aerial data of our MatrixCity dataset." + ], + "image_footnote": [], + "bbox": [ + 80, + 400, + 233, + 453 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/549c1711a84823d51881ebe1ad93c3ee94cac82ceb5abb8f2f47452b8e48f90b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 243, + 401, + 395, + 453 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/6f3dcfc6c6f3319fa39f11396a88bdb2d7bae36ece2204779a2dd6250b2e8a93.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 406, + 398, + 560, + 450 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/37a42ec35a471a3b507fc727123d918c110a7e9580483b8e3f6efddad7b7d93c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 570, + 398, + 723, + 450 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/617755d21edb6d2768be99db15ae50462d6c9aecfb42bb751a43fbe9f0b5126e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 735, + 398, + 888, + 450 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "contains more details, we also ablate the street data collection density in Table 4, which demonstrates that grid-based method is more sensitive to data density than MLP-based NeRF method. Additionally, we provide a super dense version street data with $135k$ for Small City with $1\\mathrm{m}$ interval. For demonstrative purpose, we conducted experiments on the Small City in this stage, where the interval between adjacent frames is $5\\mathrm{m}$ for street data. We will release the data splits of the following sections.", + "bbox": [ + 75, + 536, + 468, + 672 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Evaluation metric. We evaluate the rendering performance of each baseline method based on PSNR(Peak Signal-to-Noise Ratio), SSIM(Structural Similarity) [35] and the VGG implementation of LPIPS [41]. And we also use mean angular error (MAE) and mean squared error (MSE) to evaluate estimated normal vectors and depth map, respectively.", + "bbox": [ + 75, + 679, + 468, + 770 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.2. Baselines.", + "text_level": 1, + "bbox": [ + 76, + 784, + 187, + 799 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We aim to test the performance of current neural rendering methods on the MatrixCity dataset to explore the challenges for city-scale neural rendering. To achieve this, we choose five widely recognized methods: NeRF [22], DVGO [28], Instant-NGP [23], TensoRF [7] and MipNeRF-360 [4]. Note that we all use the official implementation of", + "bbox": [ + 75, + 810, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "these baselines except NeRF and Instant-NGP. For NeRF we use the widely recognized Pytorch version [39]. And for Instant-NGP, we use the open-source version [24]. We find that ngp-pl [24] generally performs better than torch-ngp [32]. To address the challenge of increasingly intricate urban content, we recognized the limited capacity of the original baseline models. So we increased the number of parameters to handle more complex urban environments. Specific details regarding these parameter increases can be found in the supplementary material.", + "bbox": [ + 496, + 536, + 892, + 686 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Neural Rendering on Aerial Data", + "text_level": 1, + "bbox": [ + 500, + 696, + 792, + 712 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Due to the limitations of current methods and models, it is impractical to use a single model to represent an entire map. Therefore, we divided the map into five blocks based on building height and coverage area. Each block covers a roughly homogeneous area, where buildings within each block have similar heights. Our results, shown in Table 2, indicate that MipNeRF-360 [4] and Instant-NGP [23] perform better, while NeRF [22] performs the worst. This indicates that grid-based methods and MLP-based NeRF methods both can model the block-size aerial data modeling well. Despite scaling up the NeRF model significantly, its ability to model large-scale scenes remains limited, as illus", + "bbox": [ + 496, + 719, + 893, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "3211", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1d742d12e9c0410fa15d8e19d54b454245993da18287585a8264f38d71d47653.jpg", + "image_caption": [ + "(a)" + ], + "image_footnote": [], + "bbox": [ + 130, + 87, + 251, + 181 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/85c7c5453911f599d9aba15eaf3888231c0fbde9fe4f86a0ab6ecbaf7703c389.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 256, + 87, + 377, + 181 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/ea301d09e8c836347eee1fe36022888121a8d92468635add68398b027f8639df.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 380, + 87, + 501, + 181 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/7e252dcf15a63c9ce0d61a5cd16640c65b8e185a51af50bb376890e8c8fb526e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 504, + 87, + 625, + 181 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/20cd175cf3e827499c97bee41ddf3a7ed8dbd7649ff2aae195efdba49fc1d48a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 627, + 87, + 750, + 181 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/3ecc2a8dd5583dc74c115f6dbc47863eebcb0415fc36e3abb740b73ab76bd5be.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 751, + 87, + 872, + 181 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/963851ea9510586eaaca935d44076b40df54d7ef4885c132d9fd07a2a89e7d21.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 132, + 183, + 251, + 277 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/d4a15c217187980974811195f011504bbd160d2d42dc9a5274d6a3f9b41fd62d.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 256, + 183, + 377, + 277 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/1c3963cef3df740d8dff5badcf21b73dd0adeb3204539f0b372119b5fb9cb8ea.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 380, + 183, + 500, + 277 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/83a43b889525f885c77e5e87c9ef883bcb7df74d44f3bc23a04defc490d3d69c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 504, + 183, + 625, + 277 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/09813853e540994a7e5a0a9c64674d2a577ad254da8b66aa86b3c1b9c29f167e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 627, + 183, + 750, + 277 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/2b2317974bd35ea44fee18d23954ba79dc1e750c55aaf1ed30bdb9ba1471350c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 751, + 183, + 872, + 277 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/d9c576c21877bbde15f8f912c8067f2cea2b291e598cc14506519a58fc32eaa9.jpg", + "image_caption": [ + "(b)" + ], + "image_footnote": [], + "bbox": [ + 132, + 282, + 251, + 376 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/3509b280d211d4234bfff1efbfb8ff00b54c7a56939466c61276925fc7e43acb.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 256, + 282, + 375, + 376 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/98c26496069b00204e2da4e11920f9902c48110c542312a974ec59374e4e2279.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 379, + 282, + 500, + 376 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/34340dc01f89c9d061aefe735091503edfbb2de3428a78f87797313c08d9b69f.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 504, + 282, + 624, + 376 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/95fcef5302b62294f9ad3588ef0271ba02d0460cfbf40f92b575e50c969079de.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 627, + 282, + 750, + 376 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/8933a8085e59e2873a802ba9215767cbb1d696fb355ba8e7caaacb99c4b648af.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 751, + 282, + 872, + 376 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/e13ae1d51cf0a6f24e9a51932e68338f5ef8619c218583018fa72388db71891e.jpg", + "image_caption": [ + "Figure 6: Visualization of novel view synthesis of city-scale neural rendering methods on (a) Block_Small and (b) Block_A of street-view data. MLP-based NeRF methods suffer from capacity issues while grid-based baselines show severe artifacts." + ], + "image_footnote": [], + "bbox": [ + 132, + 378, + 251, + 470 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/b1e2248edbfef02751cd85e2f0cacbbc6677ec4aa28c93e593e2aaf4c06dc5ed.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 256, + 378, + 375, + 470 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/ac43ab54fe24535bc1def9c954a45e1d86328f8aefe2fa7d2f144c69023cf702.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 379, + 378, + 500, + 470 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/8e4a2483c4d3dcb4b13b6472c620676497196b3d9c6de0f31a1a3026c9d38d1c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 504, + 378, + 625, + 470 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/596d72b347a1d36a7d1beef47bcd470b5d0a5810b226d9b6c37ad0fc33347438.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 627, + 378, + 750, + 470 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/3843696584c6256335a80f8a85b576f4c0b4e9b683fde1107f2ffb02edfb5a6e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 751, + 378, + 872, + 470 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/2164062a13e0ee57cf7bd058abe268d4147a3ea3a72dd61b9c639e34f0464b18.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
BlockNeRF [22]DVGO [28]TensoRF [7]Instant-NGP [23]MipNeRF-360 [4]
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
Block_A20.120.6010.62620.470.6170.60420.930.6430.57721.960.7120.49322.000.7170.488
Block_Small22.150.6780.51122.100.7110.45422.950.7410.44522.840.7450.40824.470.8270.297
Overall21.140.6400.56921.290.6640.52921.940.6920.51122.400.7290.45123.240.7720.393
", + "bbox": [ + 81, + 541, + 890, + 603 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "trated in Figure 5. Additionally, we found that the high-rise area is more challenging to model than the floor area. In the high-rise area, there are numerous occlusions between the buildings, which is a significant challenge for aerial data modeling. From Figure 5, we can observe that current methods still struggle to accurately model small objects and reflective buildings.", + "bbox": [ + 75, + 656, + 468, + 762 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.4. Neural Rendering on Street Data", + "text_level": 1, + "bbox": [ + 76, + 771, + 366, + 787 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We first run all these baselines on the street data of Block_A and find that all the methods perform much worse than the results of the aerial data, especially for the grid-based methods, as shown in Table 3. Street data contains much more details than aerial data, and it is harder to achieve high-quality results on street data than on aerial data, which is also demonstrated in Figure 7. Thus we", + "bbox": [ + 75, + 794, + 470, + 900 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/3b66f5656f0ba854051a9f03573df5cda5cc7c3630bf09922f0ee3ca4f92060b.jpg", + "table_caption": [ + "Table 3: Performance comparison of representative neural rendering methods on the street data of our MatrixCity benchmark." + ], + "table_footnote": [], + "table_body": "
DensityInstant-NGP [23]MipNeRF-360 [4]
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
5.0 m21.4360.7330.40227.750.8660.2956
3.6 m24.9780.8030.35029.3660.8840.280
2.0 m30.0250.8850.23531.4200.9010.265
1.0 m32.4440.9120.21131.8580.9050.263
0.5 m32.9990.9210.20232.2100.9070.261
", + "bbox": [ + 504, + 654, + 890, + 747 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 4: Ablation on the density of street data collection on our MatrixCity benchmark.", + "bbox": [ + 498, + 757, + 890, + 789 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "conclude that modeling the street data of a block-size area in a single model is not reasonable and filter a crossroad data to test current methods, called Block_Small. Analyzed the results on Block_Small, we find that the MLP-based NeRF methods perform better than the grid-based methods,", + "bbox": [ + 498, + 824, + 893, + 902 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "3212", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/ce057f5f6de5fd137029ecf8a4048d7ba25f851518d0081a8d09449885650996.jpg", + "image_caption": [ + "Figure 7: Visualization of the depth and normal results of MipNeRF-360 on aerial and street views." + ], + "image_footnote": [], + "bbox": [ + 96, + 89, + 330, + 195 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/eeeff59462180ae1570f354b02dbc2ad0f3e3308c580d5cd7a8ea1624ed5da0c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 331, + 90, + 570, + 196 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/c9f2e25d9bd2a66cd45541f475823b27f857ba4d4cd365f5577088d09d1d7ae3.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 580, + 90, + 720, + 196 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/b661b6763d352115c560348063b162ee4e87fdf5b23af7a1de96b19c44e659a5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 723, + 90, + 862, + 196 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/e416d48dae908559c4f6bebb7d888806d0b775821a1e1ceee538b97f8f9e9423.jpg", + "image_caption": [ + "Figure 8: Visualization of neural rendered results on aerial and street views before and after fusion of two types of views. Streets views are generally harder than aerial views to deliver high-quality rendering results, with notable floating artifacts, where the model get easily overfitting to the training views with cheated geometry. The naive joint training on the fused data downgrades the quality." + ], + "image_footnote": [], + "bbox": [ + 78, + 263, + 472, + 391 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/a49a2b753aff4e660b8c1861ea7ab54b2e3cbd7e1f4c2c0611c09417a3fe14d7.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Data TypeTensoRF [7]MipNeRF-360 [4]
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
Aerial27.260.8290.23128.370.8550.197
Streat22.100.7270.44923.050.8050.312
Fusion21.440.6560.50417.070.4700.600
", + "bbox": [ + 80, + 535, + 468, + 604 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 5: Ablation on the fusion of aerial and street data on our MatrixCity benchmark.", + "bbox": [ + 75, + 614, + 468, + 647 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "which is also demonstrated in Figure 6. The Block_Small can also be seen as a 360 unbounded scenes with a distant background. Figure 6 shows that MipNeRF-360 can alleviate this problem to some extent. However, the reflective parts and fine-grained architectures are still not well reconstructed.", + "bbox": [ + 75, + 671, + 468, + 762 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "4.5. Neural Rendering on Joint Types of Data", + "text_level": 1, + "bbox": [ + 76, + 771, + 428, + 787 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "The major motivation to fuse data from both aerial and street view is to provide content information at different granularity. While aerial views are generally easier to train with less geometry ambiguities, it lacks many details on the near-ground, which are critical to deliver immersive experience for exploring a city. On the other hand, street-view images often only offer partial information about the scene", + "bbox": [ + 75, + 794, + 470, + 902 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "revealing the local contents, which are sensitive to overfit to training views. We therefore explore to train the aerial and street data together, which cover the same area, aiming the leverage the advantage of two sources of data to ensure wide coverage as well as fine details. However, according to Table 5, we find that the performance of TensoRF [7] and MipNeRF-360 [4] both got worse after simply fusing the aerial and street data to train together. As shown in the Figure 8, the ground part of the aerial view becomes dirty after training with the street data for both methods. For the street view, the foreground of MipNeRF-360 becomes worse. We analyze that due to the significant difference in the level of details between street-level and aerial imagery, as well as the large disparity in distance from the foreground, it is challenging to train models simply by utilizing both types of data. We need to further investigate how algorithms can effectively utilize both the geometric information from aerial imagery and the detailed information from street-level imagery, such as finetuning, progressive training, separate group of hyperparameters, etc.", + "bbox": [ + 496, + 263, + 892, + 566 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 579, + 619, + 594 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this paper, we proposed MatrixCity, a high-quality and city-scale benchmark with diverse, controllable and realistic data collected from the powerful Unreal Engine 5. Additional information like depth and normal are also collected with minimum extra cost in our MatrixCity dataset, enables other potential tasks and applications like depth estimation and inverse rendering. On top of MatrixCity, we have empirically investigated representative methods on two types of data independently and the fusion of both aerial-view and street-view data. We hope these efforts could facilitate new advances in the field of city-scale neural rendering.", + "bbox": [ + 496, + 604, + 892, + 768 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgment This project is funded in part by Shanghai AI Laboratory (P23KS00020, 2022ZD0160201), CUHK Interdisciplinary AI Research Institute, and the Centre for Perceptual and Interactive Intelligence (CPII) Ltd under the Innovation and Technology Commission (ITC)'s InnoHK. We would like to thank Haiyi Mei and Lei Yang for their invaluable help and discussions for the plug-in development.", + "bbox": [ + 496, + 770, + 893, + 891 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "3213", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Sameer Agarwal, Yasutaka Furukawa, Noah Snavely, Ian Simon, Brian Curless, Steven M. Seitz, and Richard Szeliski. Building rome in a day. Commun. ACM, 54(10):105-112, 2011.", + "[2] Dejan Azinovic, Ricardo Martin-Brualla, Dan B. Goldman, Matthias Nießner, and Justus Thies. Neural RGB-D surface reconstruction. In CVPR, pages 6280-6291. IEEE, 2022.", + "[3] Jonathan T. Barron, Ben Mildenhall, Matthew Tancik, Peter Hedman, Ricardo Martin-Brualla, and Pratul P. Srinivasan. Mip-nerf: A multiscale representation for anti-aliasing neural radiance fields. In ICCV, pages 5835–5844. IEEE, 2021.", + "[4] Jonathan T. Barron, Ben Mildenhall, Dor Verbin, Pratul P. Srinivasan, and Peter Hedman. Mip-nerf 360: Unbounded anti-aliased neural radiance fields. In CVPR, pages 5460–5469. IEEE, 2022.", + "[5] Mark Boss, Raphael Braun, Varun Jampani, Jonathan T. Barron, Ce Liu, and Hendrik P. A. Lensch. Nerd: Neural reflectance decomposition from image collections. In ICCV, pages 12664-12674. IEEE, 2021.", + "[6] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giacarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 11621-11631, 2020.", + "[7] Anpei Chen, Zexiang Xu, Andreas Geiger, Jingyi Yu, and Hao Su. Tensorf: Tensorial radiance fields. In ECCV (32), volume 13692 of Lecture Notes in Computer Science, pages 333-350. Springer, 2022.", + "[8] David J. Crandall, Andrew Owens, Noah Snavely, and Daniel P. Huttenlocher. Sfm with mrfs: Discrete-continuous optimization for large-scale structure from motion. IEEE Trans. Pattern Anal. Mach. Intell., 35(12):2841-2853, 2013.", + "[9] Angela Dai, Angel X. Chang, Manolis Savva, Maciej Halber, Thomas A. Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In CVPR, pages 2432–2443. IEEE Computer Society, 2017.", + "[10] Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, pages 5491–5500. IEEE, 2022.", + "[11] Xin Huang, Qi Zhang, Ying Feng, Hongdong Li, Xuan Wang, and Qing Wang. Hdr-nerf: High dynamic range neural radiance fields. In CVPR, pages 18377-18387. IEEE, 2022.", + "[12] Veli Ilci and Charles K. Toth. High definition 3d map creation using gnss/imu/lidar sensor integration to support autonomous vehicle navigation. Sensors, 20(3):899, 2020.", + "[13] Rasmus Ramsbøl Jensen, Anders Lindbjerg Dahl, George Vogiatzis, Engin Tola, and Henrik Aanæs. Large scale multiview stereopsis evaluation. In CVPR, pages 406-413. IEEE Computer Society, 2014.", + "[14] Kim Jun-Seong, Kim Yu-Ji, Moon Ye-Bin, and Tae-Hyun Oh. HDR-plenoxels: Self-calibrating high dynamic range radiance fields. In ECCV (32), volume 13692 of Lecture Notes in Computer Science, pages 384-401. Springer, 2022." + ], + "bbox": [ + 78, + 114, + 470, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[15] Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: benchmarking large-scale scene reconstruction. ACM Trans. Graph., 36(4):78:1-78:13, 2017.", + "[16] Yiyi Liao, Jun Xie, and Andreas Geiger. Kitti-360: A novel dataset and benchmarks for urban scene understanding in 2d and 3d. IEEE Transactions on Pattern Analysis and Machine Intelligence, 45(3):3292-3310, 2022.", + "[17] Liqiang Lin, Yilin Liu, Yue Hu, Xingguang Yan, Ke Xie, and Hui Huang. Capturing, reconstructing, and simulating: The urbanscene3d dataset. In ECCV (8), volume 13668 of Lecture Notes in Computer Science, pages 93-109. Springer, 2022.", + "[18] Lingjie Liu, Jiatao Gu, Kyaw Zaw Lin, Tat-Seng Chua, and Christian Theobalt. Neural sparse voxel fields. In NeurIPS, 2020.", + "[19] Chongshan Lu, Fukun Yin, Xin Chen, Tao Chen, Gang Yu, and Jiayuan Fan. A large-scale outdoor multi-modal dataset and benchmark for novel view synthesis and implicit scene reconstruction. CoRR, abs/2301.06782, 2023.", + "[20] Ricardo Martin-Brualla, Noha Radwan, Mehdi S. M. Sajjadi, Jonathan T. Barron, Alexey Dosovitskiy, and Daniel Duckworth. Nerf in the wild: Neural radiance fields for unconstrained photo collections. In CVPR, pages 7210-7219. IEEE, 2021.", + "[21] Ben Mildenhall, Peter Hedman, Ricardo Martin-Brualla, Pratul P. Srinivasan, and Jonathan T. Barron. Nerf in the dark: High dynamic range view synthesis from noisy raw images. In CVPR, pages 16169-16178. IEEE, 2022.", + "[22] Ben Mildenhall, Pratul P. Srinivasan, Matthew Tancik, Jonathan T. Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. In ECCV (1), volume 12346 of Lecture Notes in Computer Science, pages 405-421. Springer, 2020.", + "[23] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Trans. Graph., 41(4):102:1-102:15, 2022.", + "[24] Chen Quei-An. ngp pl: a pytorch-lightning implementation of instant-ngp, 2022. https://github.com/kwea123/ngp.pl.", + "[25] Konstantinos Rematas, Andrew Liu, Pratul P. Srinivasan, Jonathan T. Barron, Andrea Tagliasacchi, Thomas A. Funkhouser, and Vittorio Ferrari. Urban radiance fields. In CVPR, pages 12922-12932. IEEE, 2022.", + "[26] Viktor Rudnev, Mohamed Elgharib, William A. P. Smith, Lingjie Liu, Vladislav Golyanik, and Christian Theobalt. Nerf for outdoor scene relighting. In ECCV (16), volume 13676 of Lecture Notes in Computer Science, pages 615-631. Springer, 2022.", + "[27] Pratul P. Srinivasan, Boyang Deng, Xiuming Zhang, Matthew Tancik, Ben Mildenhall, and Jonathan T. Barron. Nerv: Neural reflectance and visibility fields for relighting and view synthesis. In CVPR, pages 7495-7504. IEEE, 2021.", + "[28] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In CVPR, pages 5449-5459. IEEE, 2022.", + "[29] Pei Sun, Henrik Kretzschmar, Xerxes Dotiwalla, Aurelien Chouard, Vijaysai Patnaik, Paul Tsui, James Guo, Yin Zhou," + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "3214", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Yuning Chai, Benjamin Caine, et al. Scalability in perception for autonomous driving: Waymo open dataset. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2446-2454, 2020.", + "[30] Matthew Tancik, Vincent Casser, Xinchen Yan, Sabeek Pradhan, Ben P. Mildenhall, Pratul P. Srinivasan, Jonathan T. Barron, and Henrik Kretzschmar. Block-nerf: Scalable large scene neural view synthesis. In CVPR, pages 8238–8248. IEEE, 2022.", + "[31] Matthew Tancik, Ethan Weber, Evonne Ng, Ruilong Li, Brent Yi, Justin Kerr, Terrance Wang, Alexander Kristoffersen, Jake Austin, Kamyar Salahi, Abhik Ahuja, David McAllister, and Angjoo Kanazawa. Nerfstudio: A modular framework for neural radiance field development. In ACM SIGGRAPH 2023 Conference Proceedings, SIGGRAPH '23, 2023.", + "[32] Jiaxiang Tang. Torch-ngp: a pytorch implementation of instant-ngp, 2022. https://github.com/ashawkey/torch-ngp.", + "[33] Haithem Turki, Deva Ramanan, and Mahadev Satyanarayanan. Mega-nerf: Scalable construction of large-scale nerfs for virtual fly- throughs. In CVPR, pages 12912-12921. IEEE, 2022.", + "[34] Peng Wang, Lingjie Liu, Yuan Liu, Christian Theobalt, Taku Komura, and Wenping Wang. Neus: Learning neural implicit surfaces by volume rendering for multi-view reconstruction. In NeurIPS, pages 27171-27183, 2021.", + "[35] Zhou Wang, Alan C. Bovik, Hamid R. Sheikh, and Eero P. Simoncelli. Image quality assessment: from error visibility to structural similarity. IEEE Trans. Image Process., 13(4):600-612, 2004.", + "[36] Tong Wu, Jiaqi Wang, Xingang Pan, Xudong Xu, Christian Theobalt, Ziwei Liu, and Dahua Lin. Voxurf: Voxel-based efficient and accurate neural surface reconstruction. CoRR, abs/2208.12697, 2022.", + "[37] Yuanbo Xiangli, Linning Xu, Xingang Pan, Nanxuan Zhao, Anyi Rao, Christian Theobalt, Bo Dai, and Dahua Lin. Bungeenerf: Progressive neural radiance field for extreme multi-scale scene rendering. In ECCV (32), volume 13692 of Lecture Notes in Computer Science, pages 106-122. Springer, 2022.", + "[38] Lior Yariv, Jiatao Gu, Yoni Kasten, and Yaron Lipman. Volume rendering of neural implicit surfaces. In NeurIPS, pages 4805-4815, 2021.", + "[39] Lin Yen-Chen. Nerf-pytorch. https://github.com/yenchenlin/nerf-pytorch/, 2020.", + "[40] Kai Zhang, Gernot Riegler, Noah Snavely, and Vladlen Koltun. Nerf++: Analyzing and improving neural radiance fields. CoRR, abs/2010.07492, 2020.", + "[41] Richard Zhang, Phillip Isola, Alexei A. Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In CVPR, pages 586-595. IEEE, 2018.", + "[42] Xiuming Zhang, Pratul P. Srinivasan, Boyang Deng, Paul E. Debevec, William T. Freeman, and Jonathan T. Barron. Nefactor: neural factorization of shape and reflectance under an unknown illumination. ACM Trans. Graph., 40(6):237:1-237:18, 2021." + ], + "bbox": [ + 78, + 90, + 468, + 892 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "3215", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/1fb06bbc-ee8a-4da1-8280-e317a61d1b94_model.json b/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/1fb06bbc-ee8a-4da1-8280-e317a61d1b94_model.json new file mode 100644 index 0000000000000000000000000000000000000000..0b7a1648235063bca1aa88ba429c3f54be07be3b --- /dev/null +++ b/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/1fb06bbc-ee8a-4da1-8280-e317a61d1b94_model.json @@ -0,0 +1,2631 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.26, + 0.131, + 0.71, + 0.176 + ], + "angle": 0, + "content": "MatrixCity: A Large-scale City Dataset for City-scale Neural Rendering and Beyond" + }, + { + "type": "text", + "bbox": [ + 0.246, + 0.203, + 0.721, + 0.223 + ], + "angle": 0, + "content": "Yixuan Li\\(^{1*}\\), Lihan Jiang\\(^{2*}\\), Linning Xu\\(^{1}\\), Yuanbo Xiangli\\(^{1}\\)" + }, + { + "type": "text", + "bbox": [ + 0.321, + 0.224, + 0.65, + 0.242 + ], + "angle": 0, + "content": "Zhenzhi Wang\\(^{1}\\), Dahua Lin\\(^{1,2}\\), Bo Dai\\(^{2}\\)" + }, + { + "type": "text", + "bbox": [ + 0.214, + 0.242, + 0.758, + 0.261 + ], + "angle": 0, + "content": "1 The Chinese University of Hong Kong 2 Shanghai AI Laboratory" + }, + { + "type": "text", + "bbox": [ + 0.289, + 0.263, + 0.681, + 0.277 + ], + "angle": 0, + "content": "ly122@ie.cuhk.edu.hk jianglihan@pjlab.org.cn" + }, + { + "type": "text", + "bbox": [ + 0.225, + 0.28, + 0.746, + 0.295 + ], + "angle": 0, + "content": "{x1020,xy019,wz122,dhlin}@ie.cuhk.edu.hk daibo@pjlab.org.cn" + }, + { + "type": "image", + "bbox": [ + 0.125, + 0.321, + 0.326, + 0.448 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.327, + 0.323, + 0.455, + 0.448 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.455, + 0.323, + 0.587, + 0.448 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.587, + 0.323, + 0.718, + 0.448 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.719, + 0.323, + 0.851, + 0.448 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.128, + 0.452, + 0.311, + 0.569 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.311, + 0.452, + 0.505, + 0.569 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.506, + 0.452, + 0.731, + 0.569 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.729, + 0.452, + 0.851, + 0.569 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.075, + 0.58, + 0.892, + 0.657 + ], + "angle": 0, + "content": "Figure 1: An illustration of MatrixCity dataset's small city. a) We collected high-quality large-scale city scene images for a city-scale neural rendering benchmark from Unreal Engine 5, capturing various city environments from multiple viewing angles. b) Our flexible environment control can collect data under dynamic environmental factors such as varying lighting and weather conditions. c) Our developed platform also facilitates the extraction of additional properties, including depth maps and normal maps. These features open a wide range of opportunities for future research in city-scale neural rendering." + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.669, + 0.314, + 0.685 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.705, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Neural radiance fields (NeRF) and its subsequent variants have led to remarkable progress in neural rendering. While most of recent neural rendering works focus on objects and small-scale scenes, developing neural rendering methods for city-scale scenes is of great potential in many real-world applications. However, this line of research is impeded by the absence of a comprehensive and high-quality dataset, yet collecting such a dataset over real city-scale scenes is costly, sensitive, and technically infeasible. To this end, we build a large-scale, comprehensive, and high-quality synthetic dataset for city-scale neural rendering researches. Leveraging the Unreal Engine 5 City Sample project, we developed a pipeline to easily collect aerial" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.67, + 0.895, + 0.868 + ], + "angle": 0, + "content": "and street city views, accompanied by ground-truth camera poses and a range of additional data modalities. Flexible controls on environmental factors like light, weather, human and car crowd are also available in our pipeline, supporting the need of various tasks covering city-scale neural rendering and beyond. The resulting pilot dataset, MatrixCity, contains 67k aerial images and 452k street images from two city maps of total size \\(28km^2\\). On top of MatrixCity, a thorough benchmark is also conducted, which not only reveals unique challenges of the task of city-scale neural rendering, but also highlights potential improvements for future works. The dataset and code will be publicly available at the project page: https://city-super.github.io/matrixcity/." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3205" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.09, + 0.21, + 0.106 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.115, + 0.47, + 0.252 + ], + "angle": 0, + "content": "Realistic rendering of city-scale scenes is a crucial component of many real-world applications, including aerial surveying, virtual reality, film production, and gaming. While NeRF [22] has made notable advancements in rendering objects and small-scale scenes, only a few early attempts [30, 33, 37] have sought to extend NeRF and its variants to larger city-scale scenes. Due to the paucity of benchmark dataset, the complexity and challenges of city-scale neural rendering have not been thoroughly investigated." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.252, + 0.471, + 0.538 + ], + "angle": 0, + "content": "Collecting a comprehensive and high-quality city-scale dataset in real-world is time consuming and resource intensive, and can be technically infeasible. Moreover, it is also impossible to control environmental factors, such as lighting conditions, weather patterns, and the presence of transient objects like pedestrians and vehicles. Thus, existing urban datasets [17, 33, 8] are limited to a few independent scenes rather than comprehensive city maps, failing to capture the diversity of urban environments. Furthermore, existing datasets often feature monotonous viewing angles, such as street-level [30] or aerial imagery [17, 33, 8], leading to partial city modeling with incomplete building geometries and ground-level details. Even if sufficient real-world city data is collected, legal or commercial issues can limit its accessibility, e.g., Block-NeRF dataset [30] only provides access to \\(1\\mathrm{km}\\) street data, and UrbanScene3D dataset [17] offers only two real-world scenarios. Such restrictions significantly hinder the ability of researchers to advance the field of city-scale neural rendering." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.539, + 0.471, + 0.841 + ], + "angle": 0, + "content": "This paper presents MatrixCity, a comprehensive and high-quality synthetic dataset to support the research of city-scale neural rendering as well as other extended tasks. Specifically, MatrixCity has several distinguished features: 1) High Quality. It is built in the City Sample project \\(^{1}\\) of Unreal Engine \\(5^{2}\\) with advanced graphic technologies which allows for the public release of rendered images. As shown in Figure 1, this engine offers rich city details of fine-grained textures and geometries from its photo-realistic rendering quality with realistic lighting, shadow effects, and accurate ground-truth camera poses. 2) Scale and Diversity. To create the MatrixCity dataset, we developed a plugin that can automatically capture data from the map of two cities provided by Unreal Engine 5, resulting in 172k and 347k images, respectively. These images cover areas equivalent to \\(2.7\\mathrm{km}^2\\) and \\(25.3\\mathrm{km}^2\\) in the real-world. The captured regions showcase a broad spectrum of urban landscapes, mirroring the complexity and heterogeneity of genuine cities. 3) Controllable Environments. Our developed plugin provides flexible control over a range of environmental factors" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.092, + 0.892, + 0.287 + ], + "angle": 0, + "content": "that are uncontrollable in the real world, including lighting, weather, and human and car crowds. By decoupling these various factors, we are able to provide corresponding data that can support in-depth research of city-scale neural rendering. 4) Multiple Properties. The plugin can also customize data collection trajectories, and extract multiple ground-truth components, including depth, normal and decomposed components of reflectance (e.g. diffuse, specular, metallic, etc.). Such advanced feature enables researchers to not only perform a range of city-scale neural rendering tasks under varying conditions but also supports other extended tasks, for example depth estimation and inverse rendering." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.288, + 0.893, + 0.604 + ], + "angle": 0, + "content": "Our benchmark study demonstrates the value of Matrix-City in advancing city-scale neural rendering researches. We experiment with several state-of-the-art neural rendering methods to conduct empirical analyses first on aerial and street data respectively, then on the fused data from both modes. Preliminary results indicate that even with these advanced methods, city-scale neural rendering is still a far-reaching goal. Specifically, we identified several challenges: 1) In aerial data, learning high-rise city regions poses a greater challenge than low-rise/ground areas due to complex building structures and occlusion; 2) Street data contains significantly more details than aerial data, which raises challenges for model capacity. Although block-size aerial data modeling is feasible, modeling street data with the same size may be more difficult; 3) The view direction and level of details varied significantly between the two modes of data, making it difficult to train them together; 4) Current models generally performed poorly on smaller objects with more details and reflective buildings in urban scenes. These findings present significant opportunities to advance research in city-scale neural rendering." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.605, + 0.82, + 0.62 + ], + "angle": 0, + "content": "In summary, our contributions are as follows:" + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.627, + 0.892, + 0.749 + ], + "angle": 0, + "content": "- We constructed a large-scale, high-quality dataset for city-scale neural rendering, named MatrixCity. This dataset emphasizes attributes pivotal to city-scale scenes, encompassing elements like dynamic interactions and lighting conditions. MatrixCity contains both aerial and street-level images of complete city maps with extra depth, normal, and decomposed BRDF materials capable of supporting multiple tasks." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.756, + 0.892, + 0.861 + ], + "angle": 0, + "content": "- We developed a plugin that leverages Unreal Engine 5 for automatic high-quality city data collection, allowing researchers to flexibly control lighting, weather, and transient objects. The plugin simplifies data collection for different task settings, making it a valuable tool for the community where users can build up advanced datasets as demanded." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "- We conducted extensive studies on the MatrixCity dataset, which revealed some key challenges of city" + }, + { + "type": "list", + "bbox": [ + 0.519, + 0.627, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_footnote", + "bbox": [ + 0.078, + 0.85, + 0.441, + 0.875 + ], + "angle": 0, + "content": "1https://www.unrealengine.com/marketplace/en-US/product/city-sample" + }, + { + "type": "page_footnote", + "bbox": [ + 0.098, + 0.876, + 0.27, + 0.888 + ], + "angle": 0, + "content": "\\(^{2}\\)https://www.unrealengine.com/" + }, + { + "type": "page_footnote", + "bbox": [ + 0.098, + 0.888, + 0.365, + 0.9 + ], + "angle": 0, + "content": "3https://www.unrealengine.com/en-US/eula/unreal" + }, + { + "type": "list", + "bbox": [ + 0.078, + 0.85, + 0.441, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3206" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.11, + 0.092, + 0.468, + 0.121 + ], + "angle": 0, + "content": "scale neural rendering, and hopefully facilitate future research in this area." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.137, + 0.214, + 0.154 + ], + "angle": 0, + "content": "2. Related work" + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.162, + 0.415, + 0.179 + ], + "angle": 0, + "content": "2.1. 3D Neural Representation at City Scale" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.186, + 0.468, + 0.412 + ], + "angle": 0, + "content": "City-scale reconstruction has been studied for decades. Previous methods for representing geometry of a city mainly relied on raw point clouds acquired through either structure-from-motion [1] or Lidar sensors [12]. Recently, with the emergence of Neural Radiance Fields (NeRF) [22], novel view synthesis has become more efficient and effective. Numerous methods in this direction have further improved the speed [18, 28, 10, 23, 7] and accuracy [40, 3, 4] of reconstruction. NeRF is also used in a wide range of applications beyond novel view synthesis, such as inverse rendering [5, 27, 42, 26], surface reconstruction [34, 36, 2, 38] or HDR synthesis [11, 14, 21]. Although these methods demonstrate acceptable performance with small objects, grappling with urban scenes remains a significant challenge due to the limited representation capability of NeRF." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.414, + 0.468, + 0.76 + ], + "angle": 0, + "content": "Based on these observations, recent methods were proposed for reconstructing radiance fields in urban-scale scenes. NeRF-W [20] captured per-image appearance variations and separated the entire scene into static and transient components, enabling the modeling of unstructured collections of in-the-wild photographs. Block-NeRF [30] extended NeRF-W [20] to model an neighborhood of San Francisco by dividing up urban environments into individually small Block-NeRFs. Mega-NeRF [33] also adopted the advantages of NeRF-W [20] and Block-NeRF [30] by first decomposing large-scale fly-view scenes into small spatial cells and then training these cells in parallel. Urban Radiance Fields [25] synthesized novel RGB images and extracted 3D surfaces from a combination of panoramicas and Lidar inputs in the urban environments. BungeeNeRF [37] introduced progressive modeling with multi-level supervision to handle city-scale data with varying levels of detail. Despite the progress made by the aforementioned methods [20, 30, 33, 25, 37], there is no unified dataset for evaluating these methods due to their varying settings. Significant challenge still remains in the city reconstruction problem, particularly in integrating aerial data and street-level data with varying levels of detail." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.771, + 0.412, + 0.787 + ], + "angle": 0, + "content": "2.2. NeRF-based Datasets and Benchmarks" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.795, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Several benchmarks based on NeRF are proposed in the recent two years, which focus on the effective and better reconstruction of single objects [22, 18, 13], indoor scenes [9], or outdoor unbounded scenes [4, 15]. While there have been some good attempts to collect high-quality large-scale datasets using high-precision acquisition equipment [8, 17, 30, 19] as shown in Table 1, the high acquisition" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.499 + ], + "angle": 0, + "content": "costs limit their size and scale. Some datasets are limited to only a few independent scenes that are far from urban-scale or are not fully open-source due to privacy and commercial reasons. For instance, Mill 19 dataset [33] only includes two suburban-like scenes, and the Quak 6D [8] and OMMO [19] datasets focus on a limited number of independent scenes that are not city-scale. Waymo Block-NeRF [30] dataset only grants access to 100 seconds of driving data and Urban Scene3D dataset [17] only releases two real-world scenarios. Additionally, existing real-world datasets commonly provide only one type of image data, such as street-level or aerial imagery, which makes modeling buildings incomplete [17, 19]. Collecting real data in outdoor scenes poses significant challenges due to difficulties in controlling environmental factors such as pedestrian movement, weather, and lighting. As a result, a standard and comprehensive benchmark for city-scale neural rendering has not yet been established. Existing outdoor NeRF-based benchmarks like OMMO [19] are too trivial to explore and analyze the urban implicit scene representation. To address these issues, we developed a plugin in Unreal Engine 5 to easily collect aerial and street city data with ground-truth camera poses. We built a city-scale and multitasking dataset that includes both fly-view and street-view images and propose a new city-scale benchmark for neural rendering. We also provided a detailed analysis of the challenges and opportunities of NeRF in urban environments." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.51, + 0.687, + 0.527 + ], + "angle": 0, + "content": "3. MatrixCity Dataset" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.536, + 0.892, + 0.703 + ], + "angle": 0, + "content": "The MatrixCity dataset aims to introduce a new challenging benchmark to the field of city-scale neural rendering by providing comprehensive city maps consisting of both aerial and street-level data. In addition to RGB images, we also offer normal, depth, and decomposed reflectance properties to support other tasks. Moreover, we can flexibly control environmental factors, including light direction and intensity, fog density, and human or vehicle crowding, to enable simulating real-world dynamic situations. Sec 3.1 describes our data construction procedure. Sec 3.2 and 3.3 provide detailed statistics and characteristics of this dataset." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.709, + 0.699, + 0.724 + ], + "angle": 0, + "content": "3.1. Dataset Construction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.892, + 0.901 + ], + "angle": 0, + "content": "City Data Collection. Densely captured 2D images with sufficient multi-view supervision are required to learn a faithful scene geometry, especially for large city scenes. Collecting a sufficient amount of data in Unreal Engine 5 for city scenes is a complex process that requires adjusting camera trajectories to capture specific viewpoints. Although the Unreal Engine 5 offers a movie render queue plugin for high-quality image rendering, it can be time-consuming and inflexible to manually set up the position, rotation, and frame number of key points. For urban settings, it is not practical to manually set camera trajectories" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3207" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.123, + 0.092, + 0.348, + 0.228 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.168, + 0.237, + 0.298, + 0.25 + ], + "angle": 0, + "content": "(a) Aerial block splits" + }, + { + "type": "image", + "bbox": [ + 0.372, + 0.094, + 0.6, + 0.228 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.39, + 0.237, + 0.571, + 0.25 + ], + "angle": 0, + "content": "(b) Aerial trajectory in block 4" + }, + { + "type": "image", + "bbox": [ + 0.626, + 0.094, + 0.852, + 0.226 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.651, + 0.237, + 0.832, + 0.25 + ], + "angle": 0, + "content": "(c) Street trajectory in block 4" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.28, + 0.894, + 0.312 + ], + "angle": 0, + "content": "Figure 2: Illustration of data collection in the small city in Unreal Engine 5. (a) Aerial block split for the entire small city; (b&c) Camera aerial and street trajectory of block 4 (visualized in bird-eye views) used in our plugin for data collection." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.338, + 0.47, + 0.429 + ], + "angle": 0, + "content": "in a city-scale environment. To address this, we developed a plugin that automatically generates camera trajectories, reducing the need for manual annotation and increasing the efficiency of data collection. Camera trajectories generated by our plugins can be rendered in any Unreal Engine 5 scenes." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.431, + 0.471, + 0.657 + ], + "angle": 0, + "content": "For aerial-view collection, we divide the city map into 10 blocks based on building heights (Figure 2 (a)) to better capture the building details. We provide the height of every collected block in the supplementary material. Note that current neural scene representations are generally suitable for bounded scenes, where scenes with large variation in height may cast great difficulty for accurate ray sampling. We then generate trajectories using the input of camera height and the four vertices' coordinates of the corresponding block (Figure 2 (b)) Our plugin puts four cameras at each capturing location, with each camera rotating \\(90^{\\circ}\\) apart from each other in the yaw direction and identical pitch values. The pitch value for the floor area is \\(-45^{\\circ}\\), while it is \\(-60^{\\circ}\\) for high-rise area as there are more occlusions at higher levels." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.66, + 0.471, + 0.901 + ], + "angle": 0, + "content": "For street-view data collection, we manually annotate the start and end points of each road and use them as inputs to generate straight-line trajectories with our plugin. We position six perspective cameras at each capturing location to render a cube map, providing a comprehensive view of the surroundings. Note that the cube map can be naturally transformed into panorama images, which are suitable for capturing the street views as much as possible with limited camera positions. Figure 2 (c) shows the resulting street-level trajectories for a specific block. Our plugin saves the generated camera trajectories as sequence assets of Unreal Engine, which can be easily reused to render images with different environmental settings. We will enhance our plugin to support more complex camera trajectories in the future, enabling us to generate even higher quality city-scale data. Note that we adapt auto-exposure to collect data. If" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.338, + 0.893, + 0.398 + ], + "angle": 0, + "content": "we use the same fixed exposure for two types of data, the street views will be under-exposed while the aerial views will be over-exposed. HDR images will be included in the future." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.408, + 0.895, + 0.801 + ], + "angle": 0, + "content": "Quality Control. To build a high-quality dataset for city-scale neural rendering, we utilize several mechanisms to ensure that the rendered images are of high quality and that the camera poses are accurate. Rather than using the more efficient real-time rendering pipeline, which often produces flickering images, we use the movie render queue plugin to render images with movie-level standards. Additionally, we set the Engine Scalability Settings to the best, turn off the motion blur and use anti-aliasing during the rendering process to achieve the highest possible image quality. We inspect the images thoroughly after rendering to remove any aerial views that look outside the map boundaries and ensure that there are no object clippings. Unreal Engine 5 provides ground-truth camera poses, which we have further verified through additional experiments to ensure their accuracy. Even with a small set of street data, training the MipNeRF-360 [4] model yields almost perfect novel view synthesis results, as demonstrated in Figure 6. This confirms the accurate annotation of our camera poses. Overall, by adopting these mechanisms, we ensure that the Matrix-City dataset provides high-quality images with precise camera poses, which is crucial for city-scale neural rendering research. Without considering noises like inaccurate pose and motion blur, we intend to gain more insights about the intrinsic challenges of city scenes since isolating these noises from real data is generally infeasible." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Dynamic Environments. The City Sample project of Unreal Engine 5 provides a plethora of powerful functions that allow for the creation of dynamic city scenes. As shown in Figure 1, we have the ability to control the presence of moving people and cars in the scene, adding to the realism of the environment. Additionally, we can quantitatively adjust" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "3208" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.079, + 0.089, + 0.896, + 0.306 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.33, + 0.895, + 0.361 + ], + "angle": 0, + "content": "Figure 3: Illustration of controlling dynamic environment factors in Unreal Engine 5 such as illumination (a), fog density (b) and decomposed reflectance (c)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.388, + 0.473, + 0.554 + ], + "angle": 0, + "content": "the angle and intensity of the lighting to emulate the natural changes in light throughout a day, as demonstrated in Figure 3(a). We can also control the amount of fog in a scene, as shown in Figure 3(b), providing another quantitative tool for enhancing realism. Taken together, these functions allow for the simulation of almost all basic dynamic situations found in the real world. In addition, general camera noises like motion blur and defocus blur shown in Figure 4 can be simulated in Unreal Engine. Such varying lighting, weather conditions, moving objects and camera noises will lead to more realistic and accurate city-scale neural rendering." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.56, + 0.473, + 0.711 + ], + "angle": 0, + "content": "Multiple Properties. Figure 1 (c) and Figure 3 (c) illustrates the various intermediate products generated by Unreal Engine during the rendering process, including depth, normal, and decomposed components (diffuse, specular, metallic, and roughness). These attributes are especially important for studies on inverse rendering and semantic analysis, which are popular for city scene analysis. Our plugin offers the ability to extract these properties without incurring any additional costs, which can be prohibitively expensive to obtain in real-world scenarios." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.725, + 0.248, + 0.74 + ], + "angle": 0, + "content": "3.2. Dataset Statistics" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.473, + 0.903 + ], + "angle": 0, + "content": "The MatrixCity dataset comprises two scenes from the City Sample project: Small City covering an area of \\(2.7km^2\\) and Big City spanning \\(25.3km^2\\). In total, we collect 67k aerial images and 452k street-level images to ensure comprehensive coverage. As shown in Table 1, many of current datasets [17, 8, 19] do not offer the dense image captures of the whole city but small-size independent scenes. Although Waymo Block-NeRF [30] dataset densely collects an area of approximately \\(960m \\times 570m\\), it only contains street data and results in the reconstructed buildings incom" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.388, + 0.895, + 0.525 + ], + "angle": 0, + "content": "plete. All the existing datasets do not have quantitatively controllable environments including light, weather and human and car crowds, nor multiple properties like normal, depth, the decomposed reflectance components, etc, which restricts the in-depth study of city-scale neural rendering in dynamic scenes and other extension tasks. KITTI-360 [16], NuScenes [6], Waymo Open [29] are not designed for neural rendering purposes and only provide limited camera viewpoints." + }, + { + "type": "image", + "bbox": [ + 0.506, + 0.537, + 0.895, + 0.637 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.663, + 0.892, + 0.679 + ], + "angle": 0, + "content": "Figure 4: Examples of camera motion blur and defocus blur." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.705, + 0.719, + 0.72 + ], + "angle": 0, + "content": "3.3. Dataset Characteristics" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.731, + 0.895, + 0.883 + ], + "angle": 0, + "content": "High Quality. For constructing MatrixCity dataset, we use the City Sample project and the movie-level plugin named movie render queue of the Unreal Engine 5 which is demonstrated to reproduce The Matrix Awakens. Unlike games, the rendering process is not real-time and costs huge computations with pre-defined camera poses. Such movie-level rendering quality enables the collection of realistic city-scale data similar to the real world with fully dynamic environment factors. Vigorous quality control is performed during its collection phase." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.886, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Large-scale and Diversity. The City Sample project of Un" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3209" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.089, + 0.894, + 0.247 + ], + "angle": 0, + "content": "
Dataset#ImagesLevelTypesSourceLightingHuman/CarWeatherD-Reflectance
UrbanScene3D [17]128KSceneAerialSynthetic & RealXXXX
Quad 6K [8]5.1KSceneAerialRealXXXX
Mill 19 [33]3.6KSceneAerialRealXXXX
Waymo Block-NeRF [30]12KCityStreetReal✓XXX
OMMO [19]14.7KSceneAerialReal✓XXX
KITTI-360 [16]300KCityStreetRealX✓XX
NuScenes [6]1.4MCityStreetReal✓✓✓X
Waymo Open [29]1MCityStreetReal✓✓✓X
Ours519kCityAerial+StreetSynthetic✓✓✓✓
" + }, + { + "type": "table_caption", + "bbox": [ + 0.145, + 0.258, + 0.825, + 0.273 + ], + "angle": 0, + "content": "Table 1: Comparison of statistics and properties between our MatrixCity dataset with previous datasets." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.287, + 0.891, + 0.378 + ], + "angle": 0, + "content": "
BlockNeRF [22]DVGO [28]TensoRF [7]Instant-NGP [23]MipNeRF-360 [4]Average Height
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
Block_A23.150.5610.64925.040.6770.52025.960.7200.46227.210.7930.37626.640.7720.406150
Block_B22.940.6130.48522.720.6490.46324.950.7760.32625.450.8260.27124.800.7650.352432
Block_C22.150.5900.52721.390.6490.47524.110.7540.37023.210.7880.31124.200.7590.365419
Block_D23.090.5700.54824.140.6560.48624.990.7120.41626.240.7850.33826.450.7900.338250
Block_E23.530.6120.53424.740.7040.46725.660.7490.40826.360.8070.33526.540.8110.338200
Overall22.970.5890.54823.610.6670.48225.130.7620.39625.690.8000.32625.730.7790.360279
" + }, + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.388, + 0.892, + 0.404 + ], + "angle": 0, + "content": "Table 2: Performance comparison of representative neural rendering methods on the aerial data of our MatrixCity benchmark." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.43, + 0.471, + 0.537 + ], + "angle": 0, + "content": "real Engine 5 includes two cities with a large-scale coverage, which captures varying buildings, pedestrians, signs, vehicles, and lighting conditions, resulting in more diverse and realistic outdoor scenes that are representative of real-world cities. This ensures that researchers have access to a broad range of data to train their models on, leading to more accurate and effective city-scale neural rendering." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.547, + 0.47, + 0.683 + ], + "angle": 0, + "content": "Controllable Environments. Unlike the real world data, we could control the lighting angle and intensity, the density and height of fog, and the density of flow of pedestrians and vehicles in a fine-grained manner. This flexibility enables us to generate dynamic scenarios of city scenes that would be difficult to capture in real-world data. This level of control over the environment allows for more detailed exploration of how different factors influence the training process of city-scale neural rendering." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.693, + 0.47, + 0.799 + ], + "angle": 0, + "content": "Multiple Properties. Our developed plugin is able to extract additional information such as depth, normal and the decomposed reflectance components with minimum extra cost in Unreal Engine 5. This information supports additional tasks such as depth estimation, inverse rendering, which cannot be supported by real-world data without excessive labor." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.471, + 0.901 + ], + "angle": 0, + "content": "Applications. By exploring neural rendering models on MatrixCity, we can transfer the algorithms to real-world urban scenes, which can generate scene for games, virtual reality, automatic driving, and so on. The rendered scenes can also make the interactions with digital humans possible in the metaverse." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.429, + 0.633, + 0.446 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.455, + 0.892, + 0.531 + ], + "angle": 0, + "content": "In this section, we mainly investigate the quality of reconstruction and novel view rendering, and reveal the challenges of adapting existing SOTA methods on this task. Additional studies (e.g., dynamics scenes, lighting control, etc.) are provided in the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.545, + 0.704, + 0.56 + ], + "angle": 0, + "content": "4.1. Datasets and Metrics." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.569, + 0.895, + 0.903 + ], + "angle": 0, + "content": "MatrixCity benchmark. The MatrixCity dataset contains two city maps: Small City and Big City. According to the common practice in surveying and mapping that adjacent images should have an overlap of \\(70\\% - 80\\%\\), we set a camera capture location every \\(40\\mathrm{m}\\) for aerial data collection and \\(5\\mathrm{m}\\) for street data collection. Small City includes 6k aerial images and 30k street-level images, while Big City has \\(60\\mathrm{k}\\) aerial images and \\(286\\mathrm{k}\\) street-level images. Note that we remove the aerial images that look outside the map boundary manually. Also, we remove the street images that look straight down following nerfstudio [31], which crops the bottom \\(20\\%\\) of the 360 images to reduce useless information. The ratio of training set to testing set is 8:1. To ensure both completeness of training perspectives and generalization ability in testing, test set is collected separately with no location overlap with the training set. For aerial data, the yaw direction randoms from \\(0^{\\circ}\\) to \\(360^{\\circ}\\) and the pitch direction randoms from \\(-60^{\\circ}\\) to \\(-45^{\\circ}\\), and every camera location captures 1 image. For street data, the yaw direction randoms from \\(0^{\\circ}\\) to \\(90^{\\circ}\\) and every camera location captures 5 images, whose pitch and roll direction keep the same with the training set. Since the street data" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.517, + 0.957 + ], + "angle": 0, + "content": "3210" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.149, + 0.094, + 0.165, + 0.103 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.106, + 0.235, + 0.159 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.312, + 0.094, + 0.327, + 0.103 + ], + "angle": 0, + "content": "(b)" + }, + { + "type": "image", + "bbox": [ + 0.244, + 0.105, + 0.397, + 0.159 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.476, + 0.094, + 0.491, + 0.103 + ], + "angle": 0, + "content": "(c)" + }, + { + "type": "image", + "bbox": [ + 0.408, + 0.105, + 0.562, + 0.158 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.64, + 0.094, + 0.654, + 0.103 + ], + "angle": 0, + "content": "(d)" + }, + { + "type": "image", + "bbox": [ + 0.571, + 0.105, + 0.725, + 0.158 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.806, + 0.094, + 0.82, + 0.104 + ], + "angle": 0, + "content": "(e)" + }, + { + "type": "image", + "bbox": [ + 0.736, + 0.106, + 0.89, + 0.158 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.164, + 0.234, + 0.218 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.244, + 0.164, + 0.397, + 0.218 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.408, + 0.165, + 0.562, + 0.219 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.571, + 0.164, + 0.725, + 0.218 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.736, + 0.164, + 0.89, + 0.218 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.223, + 0.234, + 0.277 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.244, + 0.223, + 0.397, + 0.277 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.408, + 0.223, + 0.562, + 0.277 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.571, + 0.222, + 0.725, + 0.276 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.736, + 0.222, + 0.89, + 0.276 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.282, + 0.234, + 0.335 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.244, + 0.282, + 0.397, + 0.335 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.408, + 0.281, + 0.562, + 0.334 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.571, + 0.281, + 0.725, + 0.334 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.736, + 0.281, + 0.89, + 0.334 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.342, + 0.234, + 0.395 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.244, + 0.342, + 0.397, + 0.395 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.408, + 0.341, + 0.562, + 0.394 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.571, + 0.34, + 0.725, + 0.393 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.736, + 0.34, + 0.89, + 0.393 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.401, + 0.234, + 0.454 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.244, + 0.402, + 0.397, + 0.454 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.408, + 0.4, + 0.562, + 0.452 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.571, + 0.399, + 0.725, + 0.451 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.736, + 0.399, + 0.89, + 0.452 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.479, + 0.893, + 0.509 + ], + "angle": 0, + "content": "Figure 5: Visualization of novel view synthesis results of previous representative large-scale neural rendering methods on the aerial data of our MatrixCity dataset." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.537, + 0.47, + 0.673 + ], + "angle": 0, + "content": "contains more details, we also ablate the street data collection density in Table 4, which demonstrates that grid-based method is more sensitive to data density than MLP-based NeRF method. Additionally, we provide a super dense version street data with \\(135k\\) for Small City with \\(1\\mathrm{m}\\) interval. For demonstrative purpose, we conducted experiments on the Small City in this stage, where the interval between adjacent frames is \\(5\\mathrm{m}\\) for street data. We will release the data splits of the following sections." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.68, + 0.47, + 0.771 + ], + "angle": 0, + "content": "Evaluation metric. We evaluate the rendering performance of each baseline method based on PSNR(Peak Signal-to-Noise Ratio), SSIM(Structural Similarity) [35] and the VGG implementation of LPIPS [41]. And we also use mean angular error (MAE) and mean squared error (MSE) to evaluate estimated normal vectors and depth map, respectively." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.785, + 0.189, + 0.8 + ], + "angle": 0, + "content": "4.2. Baselines." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.471, + 0.903 + ], + "angle": 0, + "content": "We aim to test the performance of current neural rendering methods on the MatrixCity dataset to explore the challenges for city-scale neural rendering. To achieve this, we choose five widely recognized methods: NeRF [22], DVGO [28], Instant-NGP [23], TensoRF [7] and MipNeRF-360 [4]. Note that we all use the official implementation of" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.537, + 0.893, + 0.688 + ], + "angle": 0, + "content": "these baselines except NeRF and Instant-NGP. For NeRF we use the widely recognized Pytorch version [39]. And for Instant-NGP, we use the open-source version [24]. We find that ngp-pl [24] generally performs better than torch-ngp [32]. To address the challenge of increasingly intricate urban content, we recognized the limited capacity of the original baseline models. So we increased the number of parameters to handle more complex urban environments. Specific details regarding these parameter increases can be found in the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.697, + 0.794, + 0.713 + ], + "angle": 0, + "content": "4.3. Neural Rendering on Aerial Data" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.894, + 0.901 + ], + "angle": 0, + "content": "Due to the limitations of current methods and models, it is impractical to use a single model to represent an entire map. Therefore, we divided the map into five blocks based on building height and coverage area. Each block covers a roughly homogeneous area, where buildings within each block have similar heights. Our results, shown in Table 2, indicate that MipNeRF-360 [4] and Instant-NGP [23] perform better, while NeRF [22] performs the worst. This indicates that grid-based methods and MLP-based NeRF methods both can model the block-size aerial data modeling well. Despite scaling up the NeRF model significantly, its ability to model large-scale scenes remains limited, as illus" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "3211" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.105, + 0.177, + 0.128, + 0.192 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "image", + "bbox": [ + 0.132, + 0.088, + 0.253, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.258, + 0.088, + 0.379, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.382, + 0.088, + 0.502, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.088, + 0.626, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.629, + 0.088, + 0.75, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.753, + 0.088, + 0.874, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.133, + 0.184, + 0.253, + 0.279 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.257, + 0.184, + 0.378, + 0.279 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.381, + 0.184, + 0.501, + 0.279 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.184, + 0.626, + 0.279 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.629, + 0.184, + 0.75, + 0.279 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.753, + 0.184, + 0.874, + 0.279 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.133, + 0.284, + 0.253, + 0.377 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.257, + 0.284, + 0.377, + 0.377 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.38, + 0.284, + 0.501, + 0.377 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.284, + 0.625, + 0.377 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.629, + 0.284, + 0.75, + 0.377 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.753, + 0.284, + 0.873, + 0.377 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.107, + 0.372, + 0.13, + 0.387 + ], + "angle": 0, + "content": "(b)" + }, + { + "type": "image", + "bbox": [ + 0.133, + 0.379, + 0.253, + 0.472 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.257, + 0.379, + 0.377, + 0.472 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.38, + 0.379, + 0.501, + 0.472 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.379, + 0.626, + 0.472 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.629, + 0.379, + 0.75, + 0.472 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.753, + 0.379, + 0.873, + 0.472 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.496, + 0.893, + 0.528 + ], + "angle": 0, + "content": "Figure 6: Visualization of novel view synthesis of city-scale neural rendering methods on (a) Block_Small and (b) Block_A of street-view data. MLP-based NeRF methods suffer from capacity issues while grid-based baselines show severe artifacts." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.542, + 0.891, + 0.604 + ], + "angle": 0, + "content": "
BlockNeRF [22]DVGO [28]TensoRF [7]Instant-NGP [23]MipNeRF-360 [4]
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
Block_A20.120.6010.62620.470.6170.60420.930.6430.57721.960.7120.49322.000.7170.488
Block_Small22.150.6780.51122.100.7110.45422.950.7410.44522.840.7450.40824.470.8270.297
Overall21.140.6400.56921.290.6640.52921.940.6920.51122.400.7290.45123.240.7720.393
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.615, + 0.891, + 0.631 + ], + "angle": 0, + "content": "Table 3: Performance comparison of representative neural rendering methods on the street data of our MatrixCity benchmark." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.657, + 0.47, + 0.763 + ], + "angle": 0, + "content": "trated in Figure 5. Additionally, we found that the high-rise area is more challenging to model than the floor area. In the high-rise area, there are numerous occlusions between the buildings, which is a significant challenge for aerial data modeling. From Figure 5, we can observe that current methods still struggle to accurately model small objects and reflective buildings." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.772, + 0.367, + 0.789 + ], + "angle": 0, + "content": "4.4. Neural Rendering on Street Data" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.471, + 0.901 + ], + "angle": 0, + "content": "We first run all these baselines on the street data of Block_A and find that all the methods perform much worse than the results of the aerial data, especially for the grid-based methods, as shown in Table 3. Street data contains much more details than aerial data, and it is harder to achieve high-quality results on street data than on aerial data, which is also demonstrated in Figure 7. Thus we" + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.655, + 0.892, + 0.748 + ], + "angle": 0, + "content": "
DensityInstant-NGP [23]MipNeRF-360 [4]
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
5.0 m21.4360.7330.40227.750.8660.2956
3.6 m24.9780.8030.35029.3660.8840.280
2.0 m30.0250.8850.23531.4200.9010.265
1.0 m32.4440.9120.21131.8580.9050.263
0.5 m32.9990.9210.20232.2100.9070.261
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.758, + 0.892, + 0.79 + ], + "angle": 0, + "content": "Table 4: Ablation on the density of street data collection on our MatrixCity benchmark." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.825, + 0.894, + 0.903 + ], + "angle": 0, + "content": "conclude that modeling the street data of a block-size area in a single model is not reasonable and filter a crossroad data to test current methods, called Block_Small. Analyzed the results on Block_Small, we find that the MLP-based NeRF methods perform better than the grid-based methods," + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3212" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.098, + 0.09, + 0.331, + 0.196 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.333, + 0.091, + 0.571, + 0.197 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.581, + 0.091, + 0.722, + 0.197 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.724, + 0.091, + 0.864, + 0.197 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.157, + 0.222, + 0.812, + 0.238 + ], + "angle": 0, + "content": "Figure 7: Visualization of the depth and normal results of MipNeRF-360 on aerial and street views." + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.264, + 0.473, + 0.392 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.417, + 0.471, + 0.523 + ], + "angle": 0, + "content": "Figure 8: Visualization of neural rendered results on aerial and street views before and after fusion of two types of views. Streets views are generally harder than aerial views to deliver high-quality rendering results, with notable floating artifacts, where the model get easily overfitting to the training views with cheated geometry. The naive joint training on the fused data downgrades the quality." + }, + { + "type": "table", + "bbox": [ + 0.081, + 0.536, + 0.47, + 0.605 + ], + "angle": 0, + "content": "
Data TypeTensoRF [7]MipNeRF-360 [4]
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
Aerial27.260.8290.23128.370.8550.197
Streat22.100.7270.44923.050.8050.312
Fusion21.440.6560.50417.070.4700.600
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.615, + 0.47, + 0.648 + ], + "angle": 0, + "content": "Table 5: Ablation on the fusion of aerial and street data on our MatrixCity benchmark." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.672, + 0.47, + 0.763 + ], + "angle": 0, + "content": "which is also demonstrated in Figure 6. The Block_Small can also be seen as a 360 unbounded scenes with a distant background. Figure 6 shows that MipNeRF-360 can alleviate this problem to some extent. However, the reflective parts and fine-grained architectures are still not well reconstructed." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.772, + 0.429, + 0.789 + ], + "angle": 0, + "content": "4.5. Neural Rendering on Joint Types of Data" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.471, + 0.903 + ], + "angle": 0, + "content": "The major motivation to fuse data from both aerial and street view is to provide content information at different granularity. While aerial views are generally easier to train with less geometry ambiguities, it lacks many details on the near-ground, which are critical to deliver immersive experience for exploring a city. On the other hand, street-view images often only offer partial information about the scene" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.264, + 0.893, + 0.568 + ], + "angle": 0, + "content": "revealing the local contents, which are sensitive to overfit to training views. We therefore explore to train the aerial and street data together, which cover the same area, aiming the leverage the advantage of two sources of data to ensure wide coverage as well as fine details. However, according to Table 5, we find that the performance of TensoRF [7] and MipNeRF-360 [4] both got worse after simply fusing the aerial and street data to train together. As shown in the Figure 8, the ground part of the aerial view becomes dirty after training with the street data for both methods. For the street view, the foreground of MipNeRF-360 becomes worse. We analyze that due to the significant difference in the level of details between street-level and aerial imagery, as well as the large disparity in distance from the foreground, it is challenging to train models simply by utilizing both types of data. We need to further investigate how algorithms can effectively utilize both the geometric information from aerial imagery and the detailed information from street-level imagery, such as finetuning, progressive training, separate group of hyperparameters, etc." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.58, + 0.62, + 0.595 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.605, + 0.893, + 0.77 + ], + "angle": 0, + "content": "In this paper, we proposed MatrixCity, a high-quality and city-scale benchmark with diverse, controllable and realistic data collected from the powerful Unreal Engine 5. Additional information like depth and normal are also collected with minimum extra cost in our MatrixCity dataset, enables other potential tasks and applications like depth estimation and inverse rendering. On top of MatrixCity, we have empirically investigated representative methods on two types of data independently and the fusion of both aerial-view and street-view data. We hope these efforts could facilitate new advances in the field of city-scale neural rendering." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.771, + 0.894, + 0.892 + ], + "angle": 0, + "content": "Acknowledgment This project is funded in part by Shanghai AI Laboratory (P23KS00020, 2022ZD0160201), CUHK Interdisciplinary AI Research Institute, and the Centre for Perceptual and Interactive Intelligence (CPII) Ltd under the Innovation and Technology Commission (ITC)'s InnoHK. We would like to thank Haiyi Mei and Lei Yang for their invaluable help and discussions for the plug-in development." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3213" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.115, + 0.47, + 0.169 + ], + "angle": 0, + "content": "[1] Sameer Agarwal, Yasutaka Furukawa, Noah Snavely, Ian Simon, Brian Curless, Steven M. Seitz, and Richard Szeliski. Building rome in a day. Commun. ACM, 54(10):105-112, 2011." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.172, + 0.47, + 0.213 + ], + "angle": 0, + "content": "[2] Dejan Azinovic, Ricardo Martin-Brualla, Dan B. Goldman, Matthias Nießner, and Justus Thies. Neural RGB-D surface reconstruction. In CVPR, pages 6280-6291. IEEE, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.215, + 0.47, + 0.269 + ], + "angle": 0, + "content": "[3] Jonathan T. Barron, Ben Mildenhall, Matthew Tancik, Peter Hedman, Ricardo Martin-Brualla, and Pratul P. Srinivasan. Mip-nerf: A multiscale representation for anti-aliasing neural radiance fields. In ICCV, pages 5835–5844. IEEE, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.271, + 0.47, + 0.324 + ], + "angle": 0, + "content": "[4] Jonathan T. Barron, Ben Mildenhall, Dor Verbin, Pratul P. Srinivasan, and Peter Hedman. Mip-nerf 360: Unbounded anti-aliased neural radiance fields. In CVPR, pages 5460–5469. IEEE, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.326, + 0.47, + 0.381 + ], + "angle": 0, + "content": "[5] Mark Boss, Raphael Braun, Varun Jampani, Jonathan T. Barron, Ce Liu, and Hendrik P. A. Lensch. Nerd: Neural reflectance decomposition from image collections. In ICCV, pages 12664-12674. IEEE, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.383, + 0.471, + 0.465 + ], + "angle": 0, + "content": "[6] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giacarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 11621-11631, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.467, + 0.47, + 0.522 + ], + "angle": 0, + "content": "[7] Anpei Chen, Zexiang Xu, Andreas Geiger, Jingyi Yu, and Hao Su. Tensorf: Tensorial radiance fields. In ECCV (32), volume 13692 of Lecture Notes in Computer Science, pages 333-350. Springer, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.524, + 0.47, + 0.577 + ], + "angle": 0, + "content": "[8] David J. Crandall, Andrew Owens, Noah Snavely, and Daniel P. Huttenlocher. Sfm with mrfs: Discrete-continuous optimization for large-scale structure from motion. IEEE Trans. Pattern Anal. Mach. Intell., 35(12):2841-2853, 2013." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.579, + 0.469, + 0.634 + ], + "angle": 0, + "content": "[9] Angela Dai, Angel X. Chang, Manolis Savva, Maciej Halber, Thomas A. Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In CVPR, pages 2432–2443. IEEE Computer Society, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.636, + 0.469, + 0.689 + ], + "angle": 0, + "content": "[10] Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, pages 5491–5500. IEEE, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.691, + 0.469, + 0.745 + ], + "angle": 0, + "content": "[11] Xin Huang, Qi Zhang, Ying Feng, Hongdong Li, Xuan Wang, and Qing Wang. Hdr-nerf: High dynamic range neural radiance fields. In CVPR, pages 18377-18387. IEEE, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.748, + 0.469, + 0.788 + ], + "angle": 0, + "content": "[12] Veli Ilci and Charles K. Toth. High definition 3d map creation using gnss/imu/lidar sensor integration to support autonomous vehicle navigation. Sensors, 20(3):899, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.79, + 0.469, + 0.844 + ], + "angle": 0, + "content": "[13] Rasmus Ramsbøl Jensen, Anders Lindbjerg Dahl, George Vogiatzis, Engin Tola, and Henrik Aanæs. Large scale multiview stereopsis evaluation. In CVPR, pages 406-413. IEEE Computer Society, 2014." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[14] Kim Jun-Seong, Kim Yu-Ji, Moon Ye-Bin, and Tae-Hyun Oh. HDR-plenoxels: Self-calibrating high dynamic range radiance fields. In ECCV (32), volume 13692 of Lecture Notes in Computer Science, pages 384-401. Springer, 2022." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.115, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.146 + ], + "angle": 0, + "content": "[15] Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: benchmarking large-scale scene reconstruction. ACM Trans. Graph., 36(4):78:1-78:13, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.149, + 0.892, + 0.203 + ], + "angle": 0, + "content": "[16] Yiyi Liao, Jun Xie, and Andreas Geiger. Kitti-360: A novel dataset and benchmarks for urban scene understanding in 2d and 3d. IEEE Transactions on Pattern Analysis and Machine Intelligence, 45(3):3292-3310, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.205, + 0.892, + 0.272 + ], + "angle": 0, + "content": "[17] Liqiang Lin, Yilin Liu, Yue Hu, Xingguang Yan, Ke Xie, and Hui Huang. Capturing, reconstructing, and simulating: The urbanscene3d dataset. In ECCV (8), volume 13668 of Lecture Notes in Computer Science, pages 93-109. Springer, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.274, + 0.892, + 0.314 + ], + "angle": 0, + "content": "[18] Lingjie Liu, Jiatao Gu, Kyaw Zaw Lin, Tat-Seng Chua, and Christian Theobalt. Neural sparse voxel fields. In NeurIPS, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.316, + 0.892, + 0.37 + ], + "angle": 0, + "content": "[19] Chongshan Lu, Fukun Yin, Xin Chen, Tao Chen, Gang Yu, and Jiayuan Fan. A large-scale outdoor multi-modal dataset and benchmark for novel view synthesis and implicit scene reconstruction. CoRR, abs/2301.06782, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.372, + 0.892, + 0.439 + ], + "angle": 0, + "content": "[20] Ricardo Martin-Brualla, Noha Radwan, Mehdi S. M. Sajjadi, Jonathan T. Barron, Alexey Dosovitskiy, and Daniel Duckworth. Nerf in the wild: Neural radiance fields for unconstrained photo collections. In CVPR, pages 7210-7219. IEEE, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.442, + 0.892, + 0.496 + ], + "angle": 0, + "content": "[21] Ben Mildenhall, Peter Hedman, Ricardo Martin-Brualla, Pratul P. Srinivasan, and Jonathan T. Barron. Nerf in the dark: High dynamic range view synthesis from noisy raw images. In CVPR, pages 16169-16178. IEEE, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.498, + 0.892, + 0.566 + ], + "angle": 0, + "content": "[22] Ben Mildenhall, Pratul P. Srinivasan, Matthew Tancik, Jonathan T. Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. In ECCV (1), volume 12346 of Lecture Notes in Computer Science, pages 405-421. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.568, + 0.892, + 0.62 + ], + "angle": 0, + "content": "[23] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Trans. Graph., 41(4):102:1-102:15, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.623, + 0.892, + 0.65 + ], + "angle": 0, + "content": "[24] Chen Quei-An. ngp pl: a pytorch-lightning implementation of instant-ngp, 2022. https://github.com/kwea123/ngp.pl." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.652, + 0.892, + 0.704 + ], + "angle": 0, + "content": "[25] Konstantinos Rematas, Andrew Liu, Pratul P. Srinivasan, Jonathan T. Barron, Andrea Tagliasacchi, Thomas A. Funkhouser, and Vittorio Ferrari. Urban radiance fields. In CVPR, pages 12922-12932. IEEE, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.707, + 0.892, + 0.775 + ], + "angle": 0, + "content": "[26] Viktor Rudnev, Mohamed Elgharib, William A. P. Smith, Lingjie Liu, Vladislav Golyanik, and Christian Theobalt. Nerf for outdoor scene relighting. In ECCV (16), volume 13676 of Lecture Notes in Computer Science, pages 615-631. Springer, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.777, + 0.892, + 0.831 + ], + "angle": 0, + "content": "[27] Pratul P. Srinivasan, Boyang Deng, Xiuming Zhang, Matthew Tancik, Ben Mildenhall, and Jonathan T. Barron. Nerv: Neural reflectance and visibility fields for relighting and view synthesis. In CVPR, pages 7495-7504. IEEE, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.832, + 0.892, + 0.872 + ], + "angle": 0, + "content": "[28] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In CVPR, pages 5449-5459. IEEE, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.874, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[29] Pei Sun, Henrik Kretzschmar, Xerxes Dotiwalla, Aurelien Chouard, Vijaysai Patnaik, Paul Tsui, James Guo, Yin Zhou," + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "3214" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.148 + ], + "angle": 0, + "content": "Yuning Chai, Benjamin Caine, et al. Scalability in perception for autonomous driving: Waymo open dataset. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2446-2454, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.15, + 0.47, + 0.217 + ], + "angle": 0, + "content": "[30] Matthew Tancik, Vincent Casser, Xinchen Yan, Sabeek Pradhan, Ben P. Mildenhall, Pratul P. Srinivasan, Jonathan T. Barron, and Henrik Kretzschmar. Block-nerf: Scalable large scene neural view synthesis. In CVPR, pages 8238–8248. IEEE, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.219, + 0.47, + 0.315 + ], + "angle": 0, + "content": "[31] Matthew Tancik, Ethan Weber, Evonne Ng, Ruilong Li, Brent Yi, Justin Kerr, Terrance Wang, Alexander Kristoffersen, Jake Austin, Kamyar Salahi, Abhik Ahuja, David McAllister, and Angjoo Kanazawa. Nerfstudio: A modular framework for neural radiance field development. In ACM SIGGRAPH 2023 Conference Proceedings, SIGGRAPH '23, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.318, + 0.47, + 0.346 + ], + "angle": 0, + "content": "[32] Jiaxiang Tang. Torch-ngp: a pytorch implementation of instant-ngp, 2022. https://github.com/ashawkey/torch-ngp." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.347, + 0.47, + 0.401 + ], + "angle": 0, + "content": "[33] Haithem Turki, Deva Ramanan, and Mahadev Satyanarayanan. Mega-nerf: Scalable construction of large-scale nerfs for virtual fly- throughs. In CVPR, pages 12912-12921. IEEE, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.402, + 0.47, + 0.457 + ], + "angle": 0, + "content": "[34] Peng Wang, Lingjie Liu, Yuan Liu, Christian Theobalt, Taku Komura, and Wenping Wang. Neus: Learning neural implicit surfaces by volume rendering for multi-view reconstruction. In NeurIPS, pages 27171-27183, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.459, + 0.47, + 0.513 + ], + "angle": 0, + "content": "[35] Zhou Wang, Alan C. Bovik, Hamid R. Sheikh, and Eero P. Simoncelli. Image quality assessment: from error visibility to structural similarity. IEEE Trans. Image Process., 13(4):600-612, 2004." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.515, + 0.47, + 0.569 + ], + "angle": 0, + "content": "[36] Tong Wu, Jiaqi Wang, Xingang Pan, Xudong Xu, Christian Theobalt, Ziwei Liu, and Dahua Lin. Voxurf: Voxel-based efficient and accurate neural surface reconstruction. CoRR, abs/2208.12697, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.571, + 0.47, + 0.655 + ], + "angle": 0, + "content": "[37] Yuanbo Xiangli, Linning Xu, Xingang Pan, Nanxuan Zhao, Anyi Rao, Christian Theobalt, Bo Dai, and Dahua Lin. Bungeenerf: Progressive neural radiance field for extreme multi-scale scene rendering. In ECCV (32), volume 13692 of Lecture Notes in Computer Science, pages 106-122. Springer, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.656, + 0.47, + 0.696 + ], + "angle": 0, + "content": "[38] Lior Yariv, Jiatao Gu, Yoni Kasten, and Yaron Lipman. Volume rendering of neural implicit surfaces. In NeurIPS, pages 4805-4815, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.698, + 0.47, + 0.726 + ], + "angle": 0, + "content": "[39] Lin Yen-Chen. Nerf-pytorch. https://github.com/yenchenlin/nerf-pytorch/, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.727, + 0.47, + 0.767 + ], + "angle": 0, + "content": "[40] Kai Zhang, Gernot Riegler, Noah Snavely, and Vladlen Koltun. Nerf++: Analyzing and improving neural radiance fields. CoRR, abs/2010.07492, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.769, + 0.47, + 0.823 + ], + "angle": 0, + "content": "[41] Richard Zhang, Phillip Isola, Alexei A. Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In CVPR, pages 586-595. IEEE, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.825, + 0.47, + 0.893 + ], + "angle": 0, + "content": "[42] Xiuming Zhang, Pratul P. Srinivasan, Boyang Deng, Paul E. Debevec, William T. Freeman, and Jonathan T. Barron. Nefactor: neural factorization of shape and reflectance under an unknown illumination. ACM Trans. Graph., 40(6):237:1-237:18, 2021." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.893 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "3215" + } + ] +] \ No newline at end of file diff --git a/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/1fb06bbc-ee8a-4da1-8280-e317a61d1b94_origin.pdf b/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/1fb06bbc-ee8a-4da1-8280-e317a61d1b94_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..88ae0194032741141bb8433807c71a8bdba2a5e9 --- /dev/null +++ b/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/1fb06bbc-ee8a-4da1-8280-e317a61d1b94_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:43239adbfb1ba9ccf7c0c7e6cd247fe02613cd267787df6e4490a7b232e0c06d +size 5852976 diff --git a/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/full.md b/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/full.md new file mode 100644 index 0000000000000000000000000000000000000000..a99c57c87a734538ef0aed4f3c0fc0505bb41abf --- /dev/null +++ b/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/full.md @@ -0,0 +1,371 @@ +# MatrixCity: A Large-scale City Dataset for City-scale Neural Rendering and Beyond + +Yixuan Li $^{1*}$ , Lihan Jiang $^{2*}$ , Linning Xu $^{1}$ , Yuanbo Xiangli $^{1}$ + +Zhenzhi Wang $^{1}$ , Dahua Lin $^{1,2}$ , Bo Dai $^{2}$ + +1 The Chinese University of Hong Kong 2 Shanghai AI Laboratory + +ly122@ie.cuhk.edu.hk jianglihan@pjlab.org.cn + +{x1020,xy019,wz122,dhlin}@ie.cuhk.edu.hk daibo@pjlab.org.cn + +![](images/ffc577d43c3d9084dbd9a57a6066482c51bba44cfdb73cc74a65bea46431ec83.jpg) + +![](images/4488920490e2240752b12acb8ed42149b4da4260f83f2f002f1647b5d3093a94.jpg) + +![](images/bf1f3b5c8849b58f1e42d402fb36bd3842ec365b1df62de3470877236224bcac.jpg) + +![](images/63838a31527cccd3037f8978c7aaa598a228d606b8f3005d5823c28cdbfa7ec4.jpg) + +![](images/ea45c4e15e8d633a7e2e1d49923ffad2e08d0aeda85a81482a6d9c634db38c48.jpg) + +![](images/31b506e8013a3500158603eb66b36adb7dfe8aca35cba258ae149d076bc7edd9.jpg) +Figure 1: An illustration of MatrixCity dataset's small city. a) We collected high-quality large-scale city scene images for a city-scale neural rendering benchmark from Unreal Engine 5, capturing various city environments from multiple viewing angles. b) Our flexible environment control can collect data under dynamic environmental factors such as varying lighting and weather conditions. c) Our developed platform also facilitates the extraction of additional properties, including depth maps and normal maps. These features open a wide range of opportunities for future research in city-scale neural rendering. + +![](images/3382002608ea0464ffb32f81ab742c7cc9629ff8a43da3f4c8aee5205d33d9ed.jpg) + +![](images/015b38a5c12159dd47d74857989e246806437689c5f873f1200d26bea0064c2f.jpg) + +![](images/5715816fea391e7bc1118e82cb904304b5c5212498bacfc70bd24d68dd1b55f1.jpg) + +# Abstract + +Neural radiance fields (NeRF) and its subsequent variants have led to remarkable progress in neural rendering. While most of recent neural rendering works focus on objects and small-scale scenes, developing neural rendering methods for city-scale scenes is of great potential in many real-world applications. However, this line of research is impeded by the absence of a comprehensive and high-quality dataset, yet collecting such a dataset over real city-scale scenes is costly, sensitive, and technically infeasible. To this end, we build a large-scale, comprehensive, and high-quality synthetic dataset for city-scale neural rendering researches. Leveraging the Unreal Engine 5 City Sample project, we developed a pipeline to easily collect aerial + +and street city views, accompanied by ground-truth camera poses and a range of additional data modalities. Flexible controls on environmental factors like light, weather, human and car crowd are also available in our pipeline, supporting the need of various tasks covering city-scale neural rendering and beyond. The resulting pilot dataset, MatrixCity, contains 67k aerial images and 452k street images from two city maps of total size $28km^2$ . On top of MatrixCity, a thorough benchmark is also conducted, which not only reveals unique challenges of the task of city-scale neural rendering, but also highlights potential improvements for future works. The dataset and code will be publicly available at the project page: https://city-super.github.io/matrixcity/. + +# 1. Introduction + +Realistic rendering of city-scale scenes is a crucial component of many real-world applications, including aerial surveying, virtual reality, film production, and gaming. While NeRF [22] has made notable advancements in rendering objects and small-scale scenes, only a few early attempts [30, 33, 37] have sought to extend NeRF and its variants to larger city-scale scenes. Due to the paucity of benchmark dataset, the complexity and challenges of city-scale neural rendering have not been thoroughly investigated. + +Collecting a comprehensive and high-quality city-scale dataset in real-world is time consuming and resource intensive, and can be technically infeasible. Moreover, it is also impossible to control environmental factors, such as lighting conditions, weather patterns, and the presence of transient objects like pedestrians and vehicles. Thus, existing urban datasets [17, 33, 8] are limited to a few independent scenes rather than comprehensive city maps, failing to capture the diversity of urban environments. Furthermore, existing datasets often feature monotonous viewing angles, such as street-level [30] or aerial imagery [17, 33, 8], leading to partial city modeling with incomplete building geometries and ground-level details. Even if sufficient real-world city data is collected, legal or commercial issues can limit its accessibility, e.g., Block-NeRF dataset [30] only provides access to $1\mathrm{km}$ street data, and UrbanScene3D dataset [17] offers only two real-world scenarios. Such restrictions significantly hinder the ability of researchers to advance the field of city-scale neural rendering. + +This paper presents MatrixCity, a comprehensive and high-quality synthetic dataset to support the research of city-scale neural rendering as well as other extended tasks. Specifically, MatrixCity has several distinguished features: 1) High Quality. It is built in the City Sample project $^{1}$ of Unreal Engine $5^{2}$ with advanced graphic technologies which allows for the public release of rendered images. As shown in Figure 1, this engine offers rich city details of fine-grained textures and geometries from its photo-realistic rendering quality with realistic lighting, shadow effects, and accurate ground-truth camera poses. 2) Scale and Diversity. To create the MatrixCity dataset, we developed a plugin that can automatically capture data from the map of two cities provided by Unreal Engine 5, resulting in 172k and 347k images, respectively. These images cover areas equivalent to $2.7\mathrm{km}^2$ and $25.3\mathrm{km}^2$ in the real-world. The captured regions showcase a broad spectrum of urban landscapes, mirroring the complexity and heterogeneity of genuine cities. 3) Controllable Environments. Our developed plugin provides flexible control over a range of environmental factors + +that are uncontrollable in the real world, including lighting, weather, and human and car crowds. By decoupling these various factors, we are able to provide corresponding data that can support in-depth research of city-scale neural rendering. 4) Multiple Properties. The plugin can also customize data collection trajectories, and extract multiple ground-truth components, including depth, normal and decomposed components of reflectance (e.g. diffuse, specular, metallic, etc.). Such advanced feature enables researchers to not only perform a range of city-scale neural rendering tasks under varying conditions but also supports other extended tasks, for example depth estimation and inverse rendering. + +Our benchmark study demonstrates the value of Matrix-City in advancing city-scale neural rendering researches. We experiment with several state-of-the-art neural rendering methods to conduct empirical analyses first on aerial and street data respectively, then on the fused data from both modes. Preliminary results indicate that even with these advanced methods, city-scale neural rendering is still a far-reaching goal. Specifically, we identified several challenges: 1) In aerial data, learning high-rise city regions poses a greater challenge than low-rise/ground areas due to complex building structures and occlusion; 2) Street data contains significantly more details than aerial data, which raises challenges for model capacity. Although block-size aerial data modeling is feasible, modeling street data with the same size may be more difficult; 3) The view direction and level of details varied significantly between the two modes of data, making it difficult to train them together; 4) Current models generally performed poorly on smaller objects with more details and reflective buildings in urban scenes. These findings present significant opportunities to advance research in city-scale neural rendering. + +In summary, our contributions are as follows: + +- We constructed a large-scale, high-quality dataset for city-scale neural rendering, named MatrixCity. This dataset emphasizes attributes pivotal to city-scale scenes, encompassing elements like dynamic interactions and lighting conditions. MatrixCity contains both aerial and street-level images of complete city maps with extra depth, normal, and decomposed BRDF materials capable of supporting multiple tasks. +- We developed a plugin that leverages Unreal Engine 5 for automatic high-quality city data collection, allowing researchers to flexibly control lighting, weather, and transient objects. The plugin simplifies data collection for different task settings, making it a valuable tool for the community where users can build up advanced datasets as demanded. +- We conducted extensive studies on the MatrixCity dataset, which revealed some key challenges of city + +scale neural rendering, and hopefully facilitate future research in this area. + +# 2. Related work + +# 2.1. 3D Neural Representation at City Scale + +City-scale reconstruction has been studied for decades. Previous methods for representing geometry of a city mainly relied on raw point clouds acquired through either structure-from-motion [1] or Lidar sensors [12]. Recently, with the emergence of Neural Radiance Fields (NeRF) [22], novel view synthesis has become more efficient and effective. Numerous methods in this direction have further improved the speed [18, 28, 10, 23, 7] and accuracy [40, 3, 4] of reconstruction. NeRF is also used in a wide range of applications beyond novel view synthesis, such as inverse rendering [5, 27, 42, 26], surface reconstruction [34, 36, 2, 38] or HDR synthesis [11, 14, 21]. Although these methods demonstrate acceptable performance with small objects, grappling with urban scenes remains a significant challenge due to the limited representation capability of NeRF. + +Based on these observations, recent methods were proposed for reconstructing radiance fields in urban-scale scenes. NeRF-W [20] captured per-image appearance variations and separated the entire scene into static and transient components, enabling the modeling of unstructured collections of in-the-wild photographs. Block-NeRF [30] extended NeRF-W [20] to model an neighborhood of San Francisco by dividing up urban environments into individually small Block-NeRFs. Mega-NeRF [33] also adopted the advantages of NeRF-W [20] and Block-NeRF [30] by first decomposing large-scale fly-view scenes into small spatial cells and then training these cells in parallel. Urban Radiance Fields [25] synthesized novel RGB images and extracted 3D surfaces from a combination of panoramicas and Lidar inputs in the urban environments. BungeeNeRF [37] introduced progressive modeling with multi-level supervision to handle city-scale data with varying levels of detail. Despite the progress made by the aforementioned methods [20, 30, 33, 25, 37], there is no unified dataset for evaluating these methods due to their varying settings. Significant challenge still remains in the city reconstruction problem, particularly in integrating aerial data and street-level data with varying levels of detail. + +# 2.2. NeRF-based Datasets and Benchmarks + +Several benchmarks based on NeRF are proposed in the recent two years, which focus on the effective and better reconstruction of single objects [22, 18, 13], indoor scenes [9], or outdoor unbounded scenes [4, 15]. While there have been some good attempts to collect high-quality large-scale datasets using high-precision acquisition equipment [8, 17, 30, 19] as shown in Table 1, the high acquisition + +costs limit their size and scale. Some datasets are limited to only a few independent scenes that are far from urban-scale or are not fully open-source due to privacy and commercial reasons. For instance, Mill 19 dataset [33] only includes two suburban-like scenes, and the Quak 6D [8] and OMMO [19] datasets focus on a limited number of independent scenes that are not city-scale. Waymo Block-NeRF [30] dataset only grants access to 100 seconds of driving data and Urban Scene3D dataset [17] only releases two real-world scenarios. Additionally, existing real-world datasets commonly provide only one type of image data, such as street-level or aerial imagery, which makes modeling buildings incomplete [17, 19]. Collecting real data in outdoor scenes poses significant challenges due to difficulties in controlling environmental factors such as pedestrian movement, weather, and lighting. As a result, a standard and comprehensive benchmark for city-scale neural rendering has not yet been established. Existing outdoor NeRF-based benchmarks like OMMO [19] are too trivial to explore and analyze the urban implicit scene representation. To address these issues, we developed a plugin in Unreal Engine 5 to easily collect aerial and street city data with ground-truth camera poses. We built a city-scale and multitasking dataset that includes both fly-view and street-view images and propose a new city-scale benchmark for neural rendering. We also provided a detailed analysis of the challenges and opportunities of NeRF in urban environments. + +# 3. MatrixCity Dataset + +The MatrixCity dataset aims to introduce a new challenging benchmark to the field of city-scale neural rendering by providing comprehensive city maps consisting of both aerial and street-level data. In addition to RGB images, we also offer normal, depth, and decomposed reflectance properties to support other tasks. Moreover, we can flexibly control environmental factors, including light direction and intensity, fog density, and human or vehicle crowding, to enable simulating real-world dynamic situations. Sec 3.1 describes our data construction procedure. Sec 3.2 and 3.3 provide detailed statistics and characteristics of this dataset. + +# 3.1. Dataset Construction + +City Data Collection. Densely captured 2D images with sufficient multi-view supervision are required to learn a faithful scene geometry, especially for large city scenes. Collecting a sufficient amount of data in Unreal Engine 5 for city scenes is a complex process that requires adjusting camera trajectories to capture specific viewpoints. Although the Unreal Engine 5 offers a movie render queue plugin for high-quality image rendering, it can be time-consuming and inflexible to manually set up the position, rotation, and frame number of key points. For urban settings, it is not practical to manually set camera trajectories + +![](images/dba1b9a66b17b62fe7ae27698d59970b39418182f6f1f7d4601c45c036acac6d.jpg) +(a) Aerial block splits + +![](images/c0dd721ca974d0114370666b42366b01b072db2d002ca382c15a372bc817864a.jpg) +(b) Aerial trajectory in block 4 +Figure 2: Illustration of data collection in the small city in Unreal Engine 5. (a) Aerial block split for the entire small city; (b&c) Camera aerial and street trajectory of block 4 (visualized in bird-eye views) used in our plugin for data collection. + +![](images/a96c06da27a4398104f48b26fe15eed2cc98e434f62112eb732c6819bb26dee7.jpg) +(c) Street trajectory in block 4 + +in a city-scale environment. To address this, we developed a plugin that automatically generates camera trajectories, reducing the need for manual annotation and increasing the efficiency of data collection. Camera trajectories generated by our plugins can be rendered in any Unreal Engine 5 scenes. + +For aerial-view collection, we divide the city map into 10 blocks based on building heights (Figure 2 (a)) to better capture the building details. We provide the height of every collected block in the supplementary material. Note that current neural scene representations are generally suitable for bounded scenes, where scenes with large variation in height may cast great difficulty for accurate ray sampling. We then generate trajectories using the input of camera height and the four vertices' coordinates of the corresponding block (Figure 2 (b)) Our plugin puts four cameras at each capturing location, with each camera rotating $90^{\circ}$ apart from each other in the yaw direction and identical pitch values. The pitch value for the floor area is $-45^{\circ}$ , while it is $-60^{\circ}$ for high-rise area as there are more occlusions at higher levels. + +For street-view data collection, we manually annotate the start and end points of each road and use them as inputs to generate straight-line trajectories with our plugin. We position six perspective cameras at each capturing location to render a cube map, providing a comprehensive view of the surroundings. Note that the cube map can be naturally transformed into panorama images, which are suitable for capturing the street views as much as possible with limited camera positions. Figure 2 (c) shows the resulting street-level trajectories for a specific block. Our plugin saves the generated camera trajectories as sequence assets of Unreal Engine, which can be easily reused to render images with different environmental settings. We will enhance our plugin to support more complex camera trajectories in the future, enabling us to generate even higher quality city-scale data. Note that we adapt auto-exposure to collect data. If + +we use the same fixed exposure for two types of data, the street views will be under-exposed while the aerial views will be over-exposed. HDR images will be included in the future. + +Quality Control. To build a high-quality dataset for city-scale neural rendering, we utilize several mechanisms to ensure that the rendered images are of high quality and that the camera poses are accurate. Rather than using the more efficient real-time rendering pipeline, which often produces flickering images, we use the movie render queue plugin to render images with movie-level standards. Additionally, we set the Engine Scalability Settings to the best, turn off the motion blur and use anti-aliasing during the rendering process to achieve the highest possible image quality. We inspect the images thoroughly after rendering to remove any aerial views that look outside the map boundaries and ensure that there are no object clippings. Unreal Engine 5 provides ground-truth camera poses, which we have further verified through additional experiments to ensure their accuracy. Even with a small set of street data, training the MipNeRF-360 [4] model yields almost perfect novel view synthesis results, as demonstrated in Figure 6. This confirms the accurate annotation of our camera poses. Overall, by adopting these mechanisms, we ensure that the Matrix-City dataset provides high-quality images with precise camera poses, which is crucial for city-scale neural rendering research. Without considering noises like inaccurate pose and motion blur, we intend to gain more insights about the intrinsic challenges of city scenes since isolating these noises from real data is generally infeasible. + +Dynamic Environments. The City Sample project of Unreal Engine 5 provides a plethora of powerful functions that allow for the creation of dynamic city scenes. As shown in Figure 1, we have the ability to control the presence of moving people and cars in the scene, adding to the realism of the environment. Additionally, we can quantitatively adjust + +![](images/1aaf2d2e8e3bdd8980447958fc7762a6d08ceb2cbf9ca763f4d66dc3c975311e.jpg) +Figure 3: Illustration of controlling dynamic environment factors in Unreal Engine 5 such as illumination (a), fog density (b) and decomposed reflectance (c). + +the angle and intensity of the lighting to emulate the natural changes in light throughout a day, as demonstrated in Figure 3(a). We can also control the amount of fog in a scene, as shown in Figure 3(b), providing another quantitative tool for enhancing realism. Taken together, these functions allow for the simulation of almost all basic dynamic situations found in the real world. In addition, general camera noises like motion blur and defocus blur shown in Figure 4 can be simulated in Unreal Engine. Such varying lighting, weather conditions, moving objects and camera noises will lead to more realistic and accurate city-scale neural rendering. + +Multiple Properties. Figure 1 (c) and Figure 3 (c) illustrates the various intermediate products generated by Unreal Engine during the rendering process, including depth, normal, and decomposed components (diffuse, specular, metallic, and roughness). These attributes are especially important for studies on inverse rendering and semantic analysis, which are popular for city scene analysis. Our plugin offers the ability to extract these properties without incurring any additional costs, which can be prohibitively expensive to obtain in real-world scenarios. + +# 3.2. Dataset Statistics + +The MatrixCity dataset comprises two scenes from the City Sample project: Small City covering an area of $2.7km^2$ and Big City spanning $25.3km^2$ . In total, we collect 67k aerial images and 452k street-level images to ensure comprehensive coverage. As shown in Table 1, many of current datasets [17, 8, 19] do not offer the dense image captures of the whole city but small-size independent scenes. Although Waymo Block-NeRF [30] dataset densely collects an area of approximately $960m \times 570m$ , it only contains street data and results in the reconstructed buildings incom + +plete. All the existing datasets do not have quantitatively controllable environments including light, weather and human and car crowds, nor multiple properties like normal, depth, the decomposed reflectance components, etc, which restricts the in-depth study of city-scale neural rendering in dynamic scenes and other extension tasks. KITTI-360 [16], NuScenes [6], Waymo Open [29] are not designed for neural rendering purposes and only provide limited camera viewpoints. + +![](images/b5e3952916ea6f7b44b92747901e77d66c457413e12a681ae6ca37c745ec2cc0.jpg) +Figure 4: Examples of camera motion blur and defocus blur. + +# 3.3. Dataset Characteristics + +High Quality. For constructing MatrixCity dataset, we use the City Sample project and the movie-level plugin named movie render queue of the Unreal Engine 5 which is demonstrated to reproduce The Matrix Awakens. Unlike games, the rendering process is not real-time and costs huge computations with pre-defined camera poses. Such movie-level rendering quality enables the collection of realistic city-scale data similar to the real world with fully dynamic environment factors. Vigorous quality control is performed during its collection phase. + +Large-scale and Diversity. The City Sample project of Un + +
Dataset#ImagesLevelTypesSourceLightingHuman/CarWeatherD-Reflectance
UrbanScene3D [17]128KSceneAerialSynthetic & RealXXXX
Quad 6K [8]5.1KSceneAerialRealXXXX
Mill 19 [33]3.6KSceneAerialRealXXXX
Waymo Block-NeRF [30]12KCityStreetReal✓XXX
OMMO [19]14.7KSceneAerialReal✓XXX
KITTI-360 [16]300KCityStreetRealX✓XX
NuScenes [6]1.4MCityStreetReal✓✓✓X
Waymo Open [29]1MCityStreetReal✓✓✓X
Ours519kCityAerial+StreetSynthetic✓✓✓✓
+ +Table 1: Comparison of statistics and properties between our MatrixCity dataset with previous datasets. + +
BlockNeRF [22]DVGO [28]TensoRF [7]Instant-NGP [23]MipNeRF-360 [4]Average Height
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
Block_A23.150.5610.64925.040.6770.52025.960.7200.46227.210.7930.37626.640.7720.406150
Block_B22.940.6130.48522.720.6490.46324.950.7760.32625.450.8260.27124.800.7650.352432
Block_C22.150.5900.52721.390.6490.47524.110.7540.37023.210.7880.31124.200.7590.365419
Block_D23.090.5700.54824.140.6560.48624.990.7120.41626.240.7850.33826.450.7900.338250
Block_E23.530.6120.53424.740.7040.46725.660.7490.40826.360.8070.33526.540.8110.338200
Overall22.970.5890.54823.610.6670.48225.130.7620.39625.690.8000.32625.730.7790.360279
+ +Table 2: Performance comparison of representative neural rendering methods on the aerial data of our MatrixCity benchmark. + +real Engine 5 includes two cities with a large-scale coverage, which captures varying buildings, pedestrians, signs, vehicles, and lighting conditions, resulting in more diverse and realistic outdoor scenes that are representative of real-world cities. This ensures that researchers have access to a broad range of data to train their models on, leading to more accurate and effective city-scale neural rendering. + +Controllable Environments. Unlike the real world data, we could control the lighting angle and intensity, the density and height of fog, and the density of flow of pedestrians and vehicles in a fine-grained manner. This flexibility enables us to generate dynamic scenarios of city scenes that would be difficult to capture in real-world data. This level of control over the environment allows for more detailed exploration of how different factors influence the training process of city-scale neural rendering. + +Multiple Properties. Our developed plugin is able to extract additional information such as depth, normal and the decomposed reflectance components with minimum extra cost in Unreal Engine 5. This information supports additional tasks such as depth estimation, inverse rendering, which cannot be supported by real-world data without excessive labor. + +Applications. By exploring neural rendering models on MatrixCity, we can transfer the algorithms to real-world urban scenes, which can generate scene for games, virtual reality, automatic driving, and so on. The rendered scenes can also make the interactions with digital humans possible in the metaverse. + +# 4. Experiments + +In this section, we mainly investigate the quality of reconstruction and novel view rendering, and reveal the challenges of adapting existing SOTA methods on this task. Additional studies (e.g., dynamics scenes, lighting control, etc.) are provided in the supplementary material. + +# 4.1. Datasets and Metrics. + +MatrixCity benchmark. The MatrixCity dataset contains two city maps: Small City and Big City. According to the common practice in surveying and mapping that adjacent images should have an overlap of $70\% - 80\%$ , we set a camera capture location every $40\mathrm{m}$ for aerial data collection and $5\mathrm{m}$ for street data collection. Small City includes 6k aerial images and 30k street-level images, while Big City has $60\mathrm{k}$ aerial images and $286\mathrm{k}$ street-level images. Note that we remove the aerial images that look outside the map boundary manually. Also, we remove the street images that look straight down following nerfstudio [31], which crops the bottom $20\%$ of the 360 images to reduce useless information. The ratio of training set to testing set is 8:1. To ensure both completeness of training perspectives and generalization ability in testing, test set is collected separately with no location overlap with the training set. For aerial data, the yaw direction randoms from $0^{\circ}$ to $360^{\circ}$ and the pitch direction randoms from $-60^{\circ}$ to $-45^{\circ}$ , and every camera location captures 1 image. For street data, the yaw direction randoms from $0^{\circ}$ to $90^{\circ}$ and every camera location captures 5 images, whose pitch and roll direction keep the same with the training set. Since the street data + +![](images/a2d6f57608e675e78379d5ead5c87581a9d97f8f795ddb315597e45ffc6376a5.jpg) +(a) + +![](images/7efc69beb5066bf13d8c1f8f7fe8ef82267b6132cd0d525e4f0dbc72982e441b.jpg) +(b) + +![](images/52d526dd38275ecbdd4c3aed1b1558d91cc8aa4e8b0e25e93013c4ee4dcdc618.jpg) +(c) + +![](images/ac7c6bf44ffb6fff2627945aaedb66d3dc74c32eda2de31519d1ce08e2c511bd.jpg) +(d) + +![](images/1813f822a44f559611da00862e23003591e3b19d2d7d677e02f375d425ae54a6.jpg) +(e) + +![](images/173e59d390a78f1d9d69cb754a988b12682306dbcb8752b37003019d37878b04.jpg) + +![](images/3baee1e69fd85e034b3f8d235b8afe23a98a5c7b00d5ed17b164e76207319149.jpg) + +![](images/cc3f57e98e3b2ad5c6d5ed1bff31cdc9a59a46609d6e78543b25f8125a4c8643.jpg) + +![](images/b3e25edfb77ad005a815d3bf031608e309d278bac5adca17224a7a06f133aecd.jpg) + +![](images/a1a50fd0d26136aadc0a924e8463884a11b3eb1ac58e3d9ee4f1481e945d51c3.jpg) + +![](images/79b2dc24e1d250ceb72897e93fc73767d98f70a954ef5d6ac09628a55175b33c.jpg) + +![](images/4c310fb0e91d88429ca7c324eaa847d61b0839f0a8ea58ddd9733c19a444879f.jpg) + +![](images/66c6eb2cbb21e8630657c63ca89d6a11c9e39e4d72015cebbdcbf426c5f398db.jpg) + +![](images/db4e6e40e4198f57cb5d9752cd4c7c7eb6e97c4971e0aed54ef5e73431321aa5.jpg) + +![](images/1711fba39d6a4b55cf609d004aec26cdeca75f69e9cb812dc4a019a37afc0d5f.jpg) + +![](images/a37d26131b6638166dbe2630e902b341cbf9e8e5ac795846ee50f50214112cec.jpg) + +![](images/a506bdf0e33bf58c600353d7628583392f73bf814ee68f686c56a4f9fa53549a.jpg) + +![](images/9a9aee706fc4a8b55126bbf59915f49eace32ae5a8dcf0f9a30e3a6ce3a7a919.jpg) + +![](images/1ae01777f307d7c415f7fbf05cf39cf67bcbc11497c54b0d00833a6d9238f4af.jpg) + +![](images/eb7cf7b07977e8bff84813ccf5a2da69805288033ee1e79c1124a6064b1335ef.jpg) + +![](images/f415401d89c9534bfebd6ae89ca9ebd3f3e1666c1d1dc20125047f1cacfc7e52.jpg) + +![](images/ffd2c28d94582a153dc45750b939397ee5e831f8be52f406923c154e6390bd06.jpg) + +![](images/df5f8b3f1dd503685f0ca65e6fe4d272478bef06c5001516c64b570b58ba8803.jpg) + +![](images/9e574bf958c0afa6d5a39fb992bbbe7ebc49de439a64ea0a8cf01bf0ffb99881.jpg) + +![](images/579f264aa39dcd92dec537a98d9a4776ecb4942167873289564431404306e9ae.jpg) + +![](images/1b5d6d54acaa2e4b773c3421b05c284fd627d498991eee280e06e4aff32968ff.jpg) +Figure 5: Visualization of novel view synthesis results of previous representative large-scale neural rendering methods on the aerial data of our MatrixCity dataset. + +![](images/549c1711a84823d51881ebe1ad93c3ee94cac82ceb5abb8f2f47452b8e48f90b.jpg) + +![](images/6f3dcfc6c6f3319fa39f11396a88bdb2d7bae36ece2204779a2dd6250b2e8a93.jpg) + +![](images/37a42ec35a471a3b507fc727123d918c110a7e9580483b8e3f6efddad7b7d93c.jpg) + +![](images/617755d21edb6d2768be99db15ae50462d6c9aecfb42bb751a43fbe9f0b5126e.jpg) + +contains more details, we also ablate the street data collection density in Table 4, which demonstrates that grid-based method is more sensitive to data density than MLP-based NeRF method. Additionally, we provide a super dense version street data with $135k$ for Small City with $1\mathrm{m}$ interval. For demonstrative purpose, we conducted experiments on the Small City in this stage, where the interval between adjacent frames is $5\mathrm{m}$ for street data. We will release the data splits of the following sections. + +Evaluation metric. We evaluate the rendering performance of each baseline method based on PSNR(Peak Signal-to-Noise Ratio), SSIM(Structural Similarity) [35] and the VGG implementation of LPIPS [41]. And we also use mean angular error (MAE) and mean squared error (MSE) to evaluate estimated normal vectors and depth map, respectively. + +# 4.2. Baselines. + +We aim to test the performance of current neural rendering methods on the MatrixCity dataset to explore the challenges for city-scale neural rendering. To achieve this, we choose five widely recognized methods: NeRF [22], DVGO [28], Instant-NGP [23], TensoRF [7] and MipNeRF-360 [4]. Note that we all use the official implementation of + +these baselines except NeRF and Instant-NGP. For NeRF we use the widely recognized Pytorch version [39]. And for Instant-NGP, we use the open-source version [24]. We find that ngp-pl [24] generally performs better than torch-ngp [32]. To address the challenge of increasingly intricate urban content, we recognized the limited capacity of the original baseline models. So we increased the number of parameters to handle more complex urban environments. Specific details regarding these parameter increases can be found in the supplementary material. + +# 4.3. Neural Rendering on Aerial Data + +Due to the limitations of current methods and models, it is impractical to use a single model to represent an entire map. Therefore, we divided the map into five blocks based on building height and coverage area. Each block covers a roughly homogeneous area, where buildings within each block have similar heights. Our results, shown in Table 2, indicate that MipNeRF-360 [4] and Instant-NGP [23] perform better, while NeRF [22] performs the worst. This indicates that grid-based methods and MLP-based NeRF methods both can model the block-size aerial data modeling well. Despite scaling up the NeRF model significantly, its ability to model large-scale scenes remains limited, as illus + +![](images/1d742d12e9c0410fa15d8e19d54b454245993da18287585a8264f38d71d47653.jpg) +(a) + +![](images/85c7c5453911f599d9aba15eaf3888231c0fbde9fe4f86a0ab6ecbaf7703c389.jpg) + +![](images/ea301d09e8c836347eee1fe36022888121a8d92468635add68398b027f8639df.jpg) + +![](images/7e252dcf15a63c9ce0d61a5cd16640c65b8e185a51af50bb376890e8c8fb526e.jpg) + +![](images/20cd175cf3e827499c97bee41ddf3a7ed8dbd7649ff2aae195efdba49fc1d48a.jpg) + +![](images/3ecc2a8dd5583dc74c115f6dbc47863eebcb0415fc36e3abb740b73ab76bd5be.jpg) + +![](images/963851ea9510586eaaca935d44076b40df54d7ef4885c132d9fd07a2a89e7d21.jpg) + +![](images/d4a15c217187980974811195f011504bbd160d2d42dc9a5274d6a3f9b41fd62d.jpg) + +![](images/1c3963cef3df740d8dff5badcf21b73dd0adeb3204539f0b372119b5fb9cb8ea.jpg) + +![](images/83a43b889525f885c77e5e87c9ef883bcb7df74d44f3bc23a04defc490d3d69c.jpg) + +![](images/09813853e540994a7e5a0a9c64674d2a577ad254da8b66aa86b3c1b9c29f167e.jpg) + +![](images/2b2317974bd35ea44fee18d23954ba79dc1e750c55aaf1ed30bdb9ba1471350c.jpg) + +![](images/d9c576c21877bbde15f8f912c8067f2cea2b291e598cc14506519a58fc32eaa9.jpg) +(b) + +![](images/3509b280d211d4234bfff1efbfb8ff00b54c7a56939466c61276925fc7e43acb.jpg) + +![](images/98c26496069b00204e2da4e11920f9902c48110c542312a974ec59374e4e2279.jpg) + +![](images/34340dc01f89c9d061aefe735091503edfbb2de3428a78f87797313c08d9b69f.jpg) + +![](images/95fcef5302b62294f9ad3588ef0271ba02d0460cfbf40f92b575e50c969079de.jpg) + +![](images/8933a8085e59e2873a802ba9215767cbb1d696fb355ba8e7caaacb99c4b648af.jpg) + +![](images/e13ae1d51cf0a6f24e9a51932e68338f5ef8619c218583018fa72388db71891e.jpg) +Figure 6: Visualization of novel view synthesis of city-scale neural rendering methods on (a) Block_Small and (b) Block_A of street-view data. MLP-based NeRF methods suffer from capacity issues while grid-based baselines show severe artifacts. + +![](images/b1e2248edbfef02751cd85e2f0cacbbc6677ec4aa28c93e593e2aaf4c06dc5ed.jpg) + +![](images/ac43ab54fe24535bc1def9c954a45e1d86328f8aefe2fa7d2f144c69023cf702.jpg) + +![](images/8e4a2483c4d3dcb4b13b6472c620676497196b3d9c6de0f31a1a3026c9d38d1c.jpg) + +![](images/596d72b347a1d36a7d1beef47bcd470b5d0a5810b226d9b6c37ad0fc33347438.jpg) + +![](images/3843696584c6256335a80f8a85b576f4c0b4e9b683fde1107f2ffb02edfb5a6e.jpg) + +
BlockNeRF [22]DVGO [28]TensoRF [7]Instant-NGP [23]MipNeRF-360 [4]
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
Block_A20.120.6010.62620.470.6170.60420.930.6430.57721.960.7120.49322.000.7170.488
Block_Small22.150.6780.51122.100.7110.45422.950.7410.44522.840.7450.40824.470.8270.297
Overall21.140.6400.56921.290.6640.52921.940.6920.51122.400.7290.45123.240.7720.393
+ +trated in Figure 5. Additionally, we found that the high-rise area is more challenging to model than the floor area. In the high-rise area, there are numerous occlusions between the buildings, which is a significant challenge for aerial data modeling. From Figure 5, we can observe that current methods still struggle to accurately model small objects and reflective buildings. + +# 4.4. Neural Rendering on Street Data + +We first run all these baselines on the street data of Block_A and find that all the methods perform much worse than the results of the aerial data, especially for the grid-based methods, as shown in Table 3. Street data contains much more details than aerial data, and it is harder to achieve high-quality results on street data than on aerial data, which is also demonstrated in Figure 7. Thus we + +Table 3: Performance comparison of representative neural rendering methods on the street data of our MatrixCity benchmark. + +
DensityInstant-NGP [23]MipNeRF-360 [4]
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
5.0 m21.4360.7330.40227.750.8660.2956
3.6 m24.9780.8030.35029.3660.8840.280
2.0 m30.0250.8850.23531.4200.9010.265
1.0 m32.4440.9120.21131.8580.9050.263
0.5 m32.9990.9210.20232.2100.9070.261
+ +Table 4: Ablation on the density of street data collection on our MatrixCity benchmark. + +conclude that modeling the street data of a block-size area in a single model is not reasonable and filter a crossroad data to test current methods, called Block_Small. Analyzed the results on Block_Small, we find that the MLP-based NeRF methods perform better than the grid-based methods, + +![](images/ce057f5f6de5fd137029ecf8a4048d7ba25f851518d0081a8d09449885650996.jpg) +Figure 7: Visualization of the depth and normal results of MipNeRF-360 on aerial and street views. + +![](images/eeeff59462180ae1570f354b02dbc2ad0f3e3308c580d5cd7a8ea1624ed5da0c.jpg) + +![](images/c9f2e25d9bd2a66cd45541f475823b27f857ba4d4cd365f5577088d09d1d7ae3.jpg) + +![](images/b661b6763d352115c560348063b162ee4e87fdf5b23af7a1de96b19c44e659a5.jpg) + +![](images/e416d48dae908559c4f6bebb7d888806d0b775821a1e1ceee538b97f8f9e9423.jpg) +Figure 8: Visualization of neural rendered results on aerial and street views before and after fusion of two types of views. Streets views are generally harder than aerial views to deliver high-quality rendering results, with notable floating artifacts, where the model get easily overfitting to the training views with cheated geometry. The naive joint training on the fused data downgrades the quality. + +
Data TypeTensoRF [7]MipNeRF-360 [4]
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
Aerial27.260.8290.23128.370.8550.197
Streat22.100.7270.44923.050.8050.312
Fusion21.440.6560.50417.070.4700.600
+ +Table 5: Ablation on the fusion of aerial and street data on our MatrixCity benchmark. + +which is also demonstrated in Figure 6. The Block_Small can also be seen as a 360 unbounded scenes with a distant background. Figure 6 shows that MipNeRF-360 can alleviate this problem to some extent. However, the reflective parts and fine-grained architectures are still not well reconstructed. + +# 4.5. Neural Rendering on Joint Types of Data + +The major motivation to fuse data from both aerial and street view is to provide content information at different granularity. While aerial views are generally easier to train with less geometry ambiguities, it lacks many details on the near-ground, which are critical to deliver immersive experience for exploring a city. On the other hand, street-view images often only offer partial information about the scene + +revealing the local contents, which are sensitive to overfit to training views. We therefore explore to train the aerial and street data together, which cover the same area, aiming the leverage the advantage of two sources of data to ensure wide coverage as well as fine details. However, according to Table 5, we find that the performance of TensoRF [7] and MipNeRF-360 [4] both got worse after simply fusing the aerial and street data to train together. As shown in the Figure 8, the ground part of the aerial view becomes dirty after training with the street data for both methods. For the street view, the foreground of MipNeRF-360 becomes worse. We analyze that due to the significant difference in the level of details between street-level and aerial imagery, as well as the large disparity in distance from the foreground, it is challenging to train models simply by utilizing both types of data. We need to further investigate how algorithms can effectively utilize both the geometric information from aerial imagery and the detailed information from street-level imagery, such as finetuning, progressive training, separate group of hyperparameters, etc. + +# 5. Conclusion + +In this paper, we proposed MatrixCity, a high-quality and city-scale benchmark with diverse, controllable and realistic data collected from the powerful Unreal Engine 5. Additional information like depth and normal are also collected with minimum extra cost in our MatrixCity dataset, enables other potential tasks and applications like depth estimation and inverse rendering. On top of MatrixCity, we have empirically investigated representative methods on two types of data independently and the fusion of both aerial-view and street-view data. We hope these efforts could facilitate new advances in the field of city-scale neural rendering. + +Acknowledgment This project is funded in part by Shanghai AI Laboratory (P23KS00020, 2022ZD0160201), CUHK Interdisciplinary AI Research Institute, and the Centre for Perceptual and Interactive Intelligence (CPII) Ltd under the Innovation and Technology Commission (ITC)'s InnoHK. We would like to thank Haiyi Mei and Lei Yang for their invaluable help and discussions for the plug-in development. + +# References + +[1] Sameer Agarwal, Yasutaka Furukawa, Noah Snavely, Ian Simon, Brian Curless, Steven M. Seitz, and Richard Szeliski. Building rome in a day. Commun. ACM, 54(10):105-112, 2011. +[2] Dejan Azinovic, Ricardo Martin-Brualla, Dan B. Goldman, Matthias Nießner, and Justus Thies. Neural RGB-D surface reconstruction. In CVPR, pages 6280-6291. IEEE, 2022. +[3] Jonathan T. Barron, Ben Mildenhall, Matthew Tancik, Peter Hedman, Ricardo Martin-Brualla, and Pratul P. Srinivasan. Mip-nerf: A multiscale representation for anti-aliasing neural radiance fields. In ICCV, pages 5835–5844. IEEE, 2021. +[4] Jonathan T. Barron, Ben Mildenhall, Dor Verbin, Pratul P. Srinivasan, and Peter Hedman. Mip-nerf 360: Unbounded anti-aliased neural radiance fields. In CVPR, pages 5460–5469. IEEE, 2022. +[5] Mark Boss, Raphael Braun, Varun Jampani, Jonathan T. Barron, Ce Liu, and Hendrik P. A. Lensch. Nerd: Neural reflectance decomposition from image collections. In ICCV, pages 12664-12674. IEEE, 2021. +[6] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giacarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 11621-11631, 2020. +[7] Anpei Chen, Zexiang Xu, Andreas Geiger, Jingyi Yu, and Hao Su. Tensorf: Tensorial radiance fields. In ECCV (32), volume 13692 of Lecture Notes in Computer Science, pages 333-350. Springer, 2022. +[8] David J. Crandall, Andrew Owens, Noah Snavely, and Daniel P. Huttenlocher. Sfm with mrfs: Discrete-continuous optimization for large-scale structure from motion. IEEE Trans. Pattern Anal. Mach. Intell., 35(12):2841-2853, 2013. +[9] Angela Dai, Angel X. Chang, Manolis Savva, Maciej Halber, Thomas A. Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In CVPR, pages 2432–2443. IEEE Computer Society, 2017. +[10] Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, pages 5491–5500. IEEE, 2022. +[11] Xin Huang, Qi Zhang, Ying Feng, Hongdong Li, Xuan Wang, and Qing Wang. Hdr-nerf: High dynamic range neural radiance fields. In CVPR, pages 18377-18387. IEEE, 2022. +[12] Veli Ilci and Charles K. Toth. High definition 3d map creation using gnss/imu/lidar sensor integration to support autonomous vehicle navigation. Sensors, 20(3):899, 2020. +[13] Rasmus Ramsbøl Jensen, Anders Lindbjerg Dahl, George Vogiatzis, Engin Tola, and Henrik Aanæs. Large scale multiview stereopsis evaluation. In CVPR, pages 406-413. IEEE Computer Society, 2014. +[14] Kim Jun-Seong, Kim Yu-Ji, Moon Ye-Bin, and Tae-Hyun Oh. HDR-plenoxels: Self-calibrating high dynamic range radiance fields. In ECCV (32), volume 13692 of Lecture Notes in Computer Science, pages 384-401. Springer, 2022. + +[15] Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: benchmarking large-scale scene reconstruction. ACM Trans. Graph., 36(4):78:1-78:13, 2017. +[16] Yiyi Liao, Jun Xie, and Andreas Geiger. Kitti-360: A novel dataset and benchmarks for urban scene understanding in 2d and 3d. IEEE Transactions on Pattern Analysis and Machine Intelligence, 45(3):3292-3310, 2022. +[17] Liqiang Lin, Yilin Liu, Yue Hu, Xingguang Yan, Ke Xie, and Hui Huang. Capturing, reconstructing, and simulating: The urbanscene3d dataset. In ECCV (8), volume 13668 of Lecture Notes in Computer Science, pages 93-109. Springer, 2022. +[18] Lingjie Liu, Jiatao Gu, Kyaw Zaw Lin, Tat-Seng Chua, and Christian Theobalt. Neural sparse voxel fields. In NeurIPS, 2020. +[19] Chongshan Lu, Fukun Yin, Xin Chen, Tao Chen, Gang Yu, and Jiayuan Fan. A large-scale outdoor multi-modal dataset and benchmark for novel view synthesis and implicit scene reconstruction. CoRR, abs/2301.06782, 2023. +[20] Ricardo Martin-Brualla, Noha Radwan, Mehdi S. M. Sajjadi, Jonathan T. Barron, Alexey Dosovitskiy, and Daniel Duckworth. Nerf in the wild: Neural radiance fields for unconstrained photo collections. In CVPR, pages 7210-7219. IEEE, 2021. +[21] Ben Mildenhall, Peter Hedman, Ricardo Martin-Brualla, Pratul P. Srinivasan, and Jonathan T. Barron. Nerf in the dark: High dynamic range view synthesis from noisy raw images. In CVPR, pages 16169-16178. IEEE, 2022. +[22] Ben Mildenhall, Pratul P. Srinivasan, Matthew Tancik, Jonathan T. Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. In ECCV (1), volume 12346 of Lecture Notes in Computer Science, pages 405-421. Springer, 2020. +[23] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Trans. Graph., 41(4):102:1-102:15, 2022. +[24] Chen Quei-An. ngp pl: a pytorch-lightning implementation of instant-ngp, 2022. https://github.com/kwea123/ngp.pl. +[25] Konstantinos Rematas, Andrew Liu, Pratul P. Srinivasan, Jonathan T. Barron, Andrea Tagliasacchi, Thomas A. Funkhouser, and Vittorio Ferrari. Urban radiance fields. In CVPR, pages 12922-12932. IEEE, 2022. +[26] Viktor Rudnev, Mohamed Elgharib, William A. P. Smith, Lingjie Liu, Vladislav Golyanik, and Christian Theobalt. Nerf for outdoor scene relighting. In ECCV (16), volume 13676 of Lecture Notes in Computer Science, pages 615-631. Springer, 2022. +[27] Pratul P. Srinivasan, Boyang Deng, Xiuming Zhang, Matthew Tancik, Ben Mildenhall, and Jonathan T. Barron. Nerv: Neural reflectance and visibility fields for relighting and view synthesis. In CVPR, pages 7495-7504. IEEE, 2021. +[28] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In CVPR, pages 5449-5459. IEEE, 2022. +[29] Pei Sun, Henrik Kretzschmar, Xerxes Dotiwalla, Aurelien Chouard, Vijaysai Patnaik, Paul Tsui, James Guo, Yin Zhou, + +Yuning Chai, Benjamin Caine, et al. Scalability in perception for autonomous driving: Waymo open dataset. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2446-2454, 2020. +[30] Matthew Tancik, Vincent Casser, Xinchen Yan, Sabeek Pradhan, Ben P. Mildenhall, Pratul P. Srinivasan, Jonathan T. Barron, and Henrik Kretzschmar. Block-nerf: Scalable large scene neural view synthesis. In CVPR, pages 8238–8248. IEEE, 2022. +[31] Matthew Tancik, Ethan Weber, Evonne Ng, Ruilong Li, Brent Yi, Justin Kerr, Terrance Wang, Alexander Kristoffersen, Jake Austin, Kamyar Salahi, Abhik Ahuja, David McAllister, and Angjoo Kanazawa. Nerfstudio: A modular framework for neural radiance field development. In ACM SIGGRAPH 2023 Conference Proceedings, SIGGRAPH '23, 2023. +[32] Jiaxiang Tang. Torch-ngp: a pytorch implementation of instant-ngp, 2022. https://github.com/ashawkey/torch-ngp. +[33] Haithem Turki, Deva Ramanan, and Mahadev Satyanarayanan. Mega-nerf: Scalable construction of large-scale nerfs for virtual fly- throughs. In CVPR, pages 12912-12921. IEEE, 2022. +[34] Peng Wang, Lingjie Liu, Yuan Liu, Christian Theobalt, Taku Komura, and Wenping Wang. Neus: Learning neural implicit surfaces by volume rendering for multi-view reconstruction. In NeurIPS, pages 27171-27183, 2021. +[35] Zhou Wang, Alan C. Bovik, Hamid R. Sheikh, and Eero P. Simoncelli. Image quality assessment: from error visibility to structural similarity. IEEE Trans. Image Process., 13(4):600-612, 2004. +[36] Tong Wu, Jiaqi Wang, Xingang Pan, Xudong Xu, Christian Theobalt, Ziwei Liu, and Dahua Lin. Voxurf: Voxel-based efficient and accurate neural surface reconstruction. CoRR, abs/2208.12697, 2022. +[37] Yuanbo Xiangli, Linning Xu, Xingang Pan, Nanxuan Zhao, Anyi Rao, Christian Theobalt, Bo Dai, and Dahua Lin. Bungeenerf: Progressive neural radiance field for extreme multi-scale scene rendering. In ECCV (32), volume 13692 of Lecture Notes in Computer Science, pages 106-122. Springer, 2022. +[38] Lior Yariv, Jiatao Gu, Yoni Kasten, and Yaron Lipman. Volume rendering of neural implicit surfaces. In NeurIPS, pages 4805-4815, 2021. +[39] Lin Yen-Chen. Nerf-pytorch. https://github.com/yenchenlin/nerf-pytorch/, 2020. +[40] Kai Zhang, Gernot Riegler, Noah Snavely, and Vladlen Koltun. Nerf++: Analyzing and improving neural radiance fields. CoRR, abs/2010.07492, 2020. +[41] Richard Zhang, Phillip Isola, Alexei A. Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In CVPR, pages 586-595. IEEE, 2018. +[42] Xiuming Zhang, Pratul P. Srinivasan, Boyang Deng, Paul E. Debevec, William T. Freeman, and Jonathan T. Barron. Nefactor: neural factorization of shape and reflectance under an unknown illumination. ACM Trans. Graph., 40(6):237:1-237:18, 2021. \ No newline at end of file diff --git a/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/images.zip b/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..54b20e97b6c5a7f006c5bbf8dc0bbde12930c1df --- /dev/null +++ b/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:bc8ffd0ec8c1d92e88aef374f25c2f5dfc7c964daf7195ac4766a23f222a2197 +size 1056838 diff --git a/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/layout.json b/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..25eaafdfe56b42952dc410e61b94ad3560a037b7 --- /dev/null +++ b/2023/MatrixCity_ A Large-scale City Dataset for City-scale Neural Rendering and Beyond/layout.json @@ -0,0 +1,9450 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 159, + 103, + 434, + 139 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 159, + 103, + 434, + 139 + ], + "spans": [ + { + "bbox": [ + 159, + 103, + 434, + 139 + ], + "type": "text", + "content": "MatrixCity: A Large-scale City Dataset for City-scale Neural Rendering and Beyond" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 150, + 160, + 441, + 176 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 150, + 160, + 441, + 176 + ], + "spans": [ + { + "bbox": [ + 150, + 160, + 441, + 176 + ], + "type": "text", + "content": "Yixuan Li" + }, + { + "bbox": [ + 150, + 160, + 441, + 176 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 150, + 160, + 441, + 176 + ], + "type": "text", + "content": ", Lihan Jiang" + }, + { + "bbox": [ + 150, + 160, + 441, + 176 + ], + "type": "inline_equation", + "content": "^{2*}" + }, + { + "bbox": [ + 150, + 160, + 441, + 176 + ], + "type": "text", + "content": ", Linning Xu" + }, + { + "bbox": [ + 150, + 160, + 441, + 176 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 150, + 160, + 441, + 176 + ], + "type": "text", + "content": ", Yuanbo Xiangli" + }, + { + "bbox": [ + 150, + 160, + 441, + 176 + ], + "type": "inline_equation", + "content": "^{1}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 196, + 177, + 397, + 191 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 196, + 177, + 397, + 191 + ], + "spans": [ + { + "bbox": [ + 196, + 177, + 397, + 191 + ], + "type": "text", + "content": "Zhenzhi Wang" + }, + { + "bbox": [ + 196, + 177, + 397, + 191 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 196, + 177, + 397, + 191 + ], + "type": "text", + "content": ", Dahua Lin" + }, + { + "bbox": [ + 196, + 177, + 397, + 191 + ], + "type": "inline_equation", + "content": "^{1,2}" + }, + { + "bbox": [ + 196, + 177, + 397, + 191 + ], + "type": "text", + "content": ", Bo Dai" + }, + { + "bbox": [ + 196, + 177, + 397, + 191 + ], + "type": "inline_equation", + "content": "^{2}" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 130, + 191, + 463, + 206 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 130, + 191, + 463, + 206 + ], + "spans": [ + { + "bbox": [ + 130, + 191, + 463, + 206 + ], + "type": "text", + "content": "1 The Chinese University of Hong Kong 2 Shanghai AI Laboratory" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 176, + 208, + 416, + 219 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 176, + 208, + 416, + 219 + ], + "spans": [ + { + "bbox": [ + 176, + 208, + 416, + 219 + ], + "type": "text", + "content": "ly122@ie.cuhk.edu.hk jianglihan@pjlab.org.cn" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 137, + 221, + 456, + 233 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 137, + 221, + 456, + 233 + ], + "spans": [ + { + "bbox": [ + 137, + 221, + 456, + 233 + ], + "type": "text", + "content": "{x1020,xy019,wz122,dhlin}@ie.cuhk.edu.hk daibo@pjlab.org.cn" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 76, + 254, + 199, + 354 + ], + "blocks": [ + { + "bbox": [ + 76, + 254, + 199, + 354 + ], + "lines": [ + { + "bbox": [ + 76, + 254, + 199, + 354 + ], + "spans": [ + { + "bbox": [ + 76, + 254, + 199, + 354 + ], + "type": "image", + "image_path": "ffc577d43c3d9084dbd9a57a6066482c51bba44cfdb73cc74a65bea46431ec83.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 200, + 255, + 278, + 354 + ], + "blocks": [ + { + "bbox": [ + 200, + 255, + 278, + 354 + ], + "lines": [ + { + "bbox": [ + 200, + 255, + 278, + 354 + ], + "spans": [ + { + "bbox": [ + 200, + 255, + 278, + 354 + ], + "type": "image", + "image_path": "4488920490e2240752b12acb8ed42149b4da4260f83f2f002f1647b5d3093a94.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 278, + 255, + 359, + 354 + ], + "blocks": [ + { + "bbox": [ + 278, + 255, + 359, + 354 + ], + "lines": [ + { + "bbox": [ + 278, + 255, + 359, + 354 + ], + "spans": [ + { + "bbox": [ + 278, + 255, + 359, + 354 + ], + "type": "image", + "image_path": "bf1f3b5c8849b58f1e42d402fb36bd3842ec365b1df62de3470877236224bcac.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 359, + 255, + 439, + 354 + ], + "blocks": [ + { + "bbox": [ + 359, + 255, + 439, + 354 + ], + "lines": [ + { + "bbox": [ + 359, + 255, + 439, + 354 + ], + "spans": [ + { + "bbox": [ + 359, + 255, + 439, + 354 + ], + "type": "image", + "image_path": "63838a31527cccd3037f8978c7aaa598a228d606b8f3005d5823c28cdbfa7ec4.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 440, + 255, + 520, + 354 + ], + "blocks": [ + { + "bbox": [ + 440, + 255, + 520, + 354 + ], + "lines": [ + { + "bbox": [ + 440, + 255, + 520, + 354 + ], + "spans": [ + { + "bbox": [ + 440, + 255, + 520, + 354 + ], + "type": "image", + "image_path": "ea45c4e15e8d633a7e2e1d49923ffad2e08d0aeda85a81482a6d9c634db38c48.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 78, + 357, + 190, + 450 + ], + "blocks": [ + { + "bbox": [ + 78, + 357, + 190, + 450 + ], + "lines": [ + { + "bbox": [ + 78, + 357, + 190, + 450 + ], + "spans": [ + { + "bbox": [ + 78, + 357, + 190, + 450 + ], + "type": "image", + "image_path": "31b506e8013a3500158603eb66b36adb7dfe8aca35cba258ae149d076bc7edd9.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 459, + 545, + 520 + ], + "lines": [ + { + "bbox": [ + 45, + 459, + 545, + 520 + ], + "spans": [ + { + "bbox": [ + 45, + 459, + 545, + 520 + ], + "type": "text", + "content": "Figure 1: An illustration of MatrixCity dataset's small city. a) We collected high-quality large-scale city scene images for a city-scale neural rendering benchmark from Unreal Engine 5, capturing various city environments from multiple viewing angles. b) Our flexible environment control can collect data under dynamic environmental factors such as varying lighting and weather conditions. c) Our developed platform also facilitates the extraction of additional properties, including depth maps and normal maps. These features open a wide range of opportunities for future research in city-scale neural rendering." + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 190, + 357, + 309, + 450 + ], + "blocks": [ + { + "bbox": [ + 190, + 357, + 309, + 450 + ], + "lines": [ + { + "bbox": [ + 190, + 357, + 309, + 450 + ], + "spans": [ + { + "bbox": [ + 190, + 357, + 309, + 450 + ], + "type": "image", + "image_path": "3382002608ea0464ffb32f81ab742c7cc9629ff8a43da3f4c8aee5205d33d9ed.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 309, + 357, + 447, + 450 + ], + "blocks": [ + { + "bbox": [ + 309, + 357, + 447, + 450 + ], + "lines": [ + { + "bbox": [ + 309, + 357, + 447, + 450 + ], + "spans": [ + { + "bbox": [ + 309, + 357, + 447, + 450 + ], + "type": "image", + "image_path": "015b38a5c12159dd47d74857989e246806437689c5f873f1200d26bea0064c2f.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 446, + 357, + 520, + 450 + ], + "blocks": [ + { + "bbox": [ + 446, + 357, + 520, + 450 + ], + "lines": [ + { + "bbox": [ + 446, + 357, + 520, + 450 + ], + "spans": [ + { + "bbox": [ + 446, + 357, + 520, + 450 + ], + "type": "image", + "image_path": "5715816fea391e7bc1118e82cb904304b5c5212498bacfc70bd24d68dd1b55f1.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + } + ], + "index": 16 + }, + { + "bbox": [ + 143, + 529, + 192, + 542 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 529, + 192, + 542 + ], + "spans": [ + { + "bbox": [ + 143, + 529, + 192, + 542 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 46, + 558, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 558, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 558, + 289, + 715 + ], + "type": "text", + "content": "Neural radiance fields (NeRF) and its subsequent variants have led to remarkable progress in neural rendering. While most of recent neural rendering works focus on objects and small-scale scenes, developing neural rendering methods for city-scale scenes is of great potential in many real-world applications. However, this line of research is impeded by the absence of a comprehensive and high-quality dataset, yet collecting such a dataset over real city-scale scenes is costly, sensitive, and technically infeasible. To this end, we build a large-scale, comprehensive, and high-quality synthetic dataset for city-scale neural rendering researches. Leveraging the Unreal Engine 5 City Sample project, we developed a pipeline to easily collect aerial" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 530, + 547, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 530, + 547, + 687 + ], + "spans": [ + { + "bbox": [ + 304, + 530, + 547, + 687 + ], + "type": "text", + "content": "and street city views, accompanied by ground-truth camera poses and a range of additional data modalities. Flexible controls on environmental factors like light, weather, human and car crowd are also available in our pipeline, supporting the need of various tasks covering city-scale neural rendering and beyond. The resulting pilot dataset, MatrixCity, contains 67k aerial images and 452k street images from two city maps of total size " + }, + { + "bbox": [ + 304, + 530, + 547, + 687 + ], + "type": "inline_equation", + "content": "28km^2" + }, + { + "bbox": [ + 304, + 530, + 547, + 687 + ], + "type": "text", + "content": ". On top of MatrixCity, a thorough benchmark is also conducted, which not only reveals unique challenges of the task of city-scale neural rendering, but also highlights potential improvements for future works. The dataset and code will be publicly available at the project page: https://city-super.github.io/matrixcity/." + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3205" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 71, + 128, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 71, + 128, + 83 + ], + "spans": [ + { + "bbox": [ + 47, + 71, + 128, + 83 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 91, + 287, + 199 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 91, + 287, + 199 + ], + "spans": [ + { + "bbox": [ + 46, + 91, + 287, + 199 + ], + "type": "text", + "content": "Realistic rendering of city-scale scenes is a crucial component of many real-world applications, including aerial surveying, virtual reality, film production, and gaming. While NeRF [22] has made notable advancements in rendering objects and small-scale scenes, only a few early attempts [30, 33, 37] have sought to extend NeRF and its variants to larger city-scale scenes. Due to the paucity of benchmark dataset, the complexity and challenges of city-scale neural rendering have not been thoroughly investigated." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 199, + 288, + 426 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 199, + 288, + 426 + ], + "spans": [ + { + "bbox": [ + 46, + 199, + 288, + 426 + ], + "type": "text", + "content": "Collecting a comprehensive and high-quality city-scale dataset in real-world is time consuming and resource intensive, and can be technically infeasible. Moreover, it is also impossible to control environmental factors, such as lighting conditions, weather patterns, and the presence of transient objects like pedestrians and vehicles. Thus, existing urban datasets [17, 33, 8] are limited to a few independent scenes rather than comprehensive city maps, failing to capture the diversity of urban environments. Furthermore, existing datasets often feature monotonous viewing angles, such as street-level [30] or aerial imagery [17, 33, 8], leading to partial city modeling with incomplete building geometries and ground-level details. Even if sufficient real-world city data is collected, legal or commercial issues can limit its accessibility, e.g., Block-NeRF dataset [30] only provides access to " + }, + { + "bbox": [ + 46, + 199, + 288, + 426 + ], + "type": "inline_equation", + "content": "1\\mathrm{km}" + }, + { + "bbox": [ + 46, + 199, + 288, + 426 + ], + "type": "text", + "content": " street data, and UrbanScene3D dataset [17] offers only two real-world scenarios. Such restrictions significantly hinder the ability of researchers to advance the field of city-scale neural rendering." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 426, + 288, + 666 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 426, + 288, + 666 + ], + "spans": [ + { + "bbox": [ + 46, + 426, + 288, + 666 + ], + "type": "text", + "content": "This paper presents MatrixCity, a comprehensive and high-quality synthetic dataset to support the research of city-scale neural rendering as well as other extended tasks. Specifically, MatrixCity has several distinguished features: 1) High Quality. It is built in the City Sample project " + }, + { + "bbox": [ + 46, + 426, + 288, + 666 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 46, + 426, + 288, + 666 + ], + "type": "text", + "content": " of Unreal Engine " + }, + { + "bbox": [ + 46, + 426, + 288, + 666 + ], + "type": "inline_equation", + "content": "5^{2}" + }, + { + "bbox": [ + 46, + 426, + 288, + 666 + ], + "type": "text", + "content": " with advanced graphic technologies which allows for the public release of rendered images. As shown in Figure 1, this engine offers rich city details of fine-grained textures and geometries from its photo-realistic rendering quality with realistic lighting, shadow effects, and accurate ground-truth camera poses. 2) Scale and Diversity. To create the MatrixCity dataset, we developed a plugin that can automatically capture data from the map of two cities provided by Unreal Engine 5, resulting in 172k and 347k images, respectively. These images cover areas equivalent to " + }, + { + "bbox": [ + 46, + 426, + 288, + 666 + ], + "type": "inline_equation", + "content": "2.7\\mathrm{km}^2" + }, + { + "bbox": [ + 46, + 426, + 288, + 666 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 426, + 288, + 666 + ], + "type": "inline_equation", + "content": "25.3\\mathrm{km}^2" + }, + { + "bbox": [ + 46, + 426, + 288, + 666 + ], + "type": "text", + "content": " in the real-world. The captured regions showcase a broad spectrum of urban landscapes, mirroring the complexity and heterogeneity of genuine cities. 3) Controllable Environments. Our developed plugin provides flexible control over a range of environmental factors" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 306, + 72, + 545, + 227 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 545, + 227 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 545, + 227 + ], + "type": "text", + "content": "that are uncontrollable in the real world, including lighting, weather, and human and car crowds. By decoupling these various factors, we are able to provide corresponding data that can support in-depth research of city-scale neural rendering. 4) Multiple Properties. The plugin can also customize data collection trajectories, and extract multiple ground-truth components, including depth, normal and decomposed components of reflectance (e.g. diffuse, specular, metallic, etc.). Such advanced feature enables researchers to not only perform a range of city-scale neural rendering tasks under varying conditions but also supports other extended tasks, for example depth estimation and inverse rendering." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 305, + 228, + 546, + 478 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 228, + 546, + 478 + ], + "spans": [ + { + "bbox": [ + 305, + 228, + 546, + 478 + ], + "type": "text", + "content": "Our benchmark study demonstrates the value of Matrix-City in advancing city-scale neural rendering researches. We experiment with several state-of-the-art neural rendering methods to conduct empirical analyses first on aerial and street data respectively, then on the fused data from both modes. Preliminary results indicate that even with these advanced methods, city-scale neural rendering is still a far-reaching goal. Specifically, we identified several challenges: 1) In aerial data, learning high-rise city regions poses a greater challenge than low-rise/ground areas due to complex building structures and occlusion; 2) Street data contains significantly more details than aerial data, which raises challenges for model capacity. Although block-size aerial data modeling is feasible, modeling street data with the same size may be more difficult; 3) The view direction and level of details varied significantly between the two modes of data, making it difficult to train them together; 4) Current models generally performed poorly on smaller objects with more details and reflective buildings in urban scenes. These findings present significant opportunities to advance research in city-scale neural rendering." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 317, + 479, + 501, + 491 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 479, + 501, + 491 + ], + "spans": [ + { + "bbox": [ + 317, + 479, + 501, + 491 + ], + "type": "text", + "content": "In summary, our contributions are as follows:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 496, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 317, + 496, + 545, + 593 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 496, + 545, + 593 + ], + "spans": [ + { + "bbox": [ + 317, + 496, + 545, + 593 + ], + "type": "text", + "content": "- We constructed a large-scale, high-quality dataset for city-scale neural rendering, named MatrixCity. This dataset emphasizes attributes pivotal to city-scale scenes, encompassing elements like dynamic interactions and lighting conditions. MatrixCity contains both aerial and street-level images of complete city maps with extra depth, normal, and decomposed BRDF materials capable of supporting multiple tasks." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 598, + 545, + 681 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 598, + 545, + 681 + ], + "spans": [ + { + "bbox": [ + 317, + 598, + 545, + 681 + ], + "type": "text", + "content": "- We developed a plugin that leverages Unreal Engine 5 for automatic high-quality city data collection, allowing researchers to flexibly control lighting, weather, and transient objects. The plugin simplifies data collection for different task settings, making it a valuable tool for the community where users can build up advanced datasets as demanded." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 317, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 317, + 689, + 545, + 713 + ], + "type": "text", + "content": "- We conducted extensive studies on the MatrixCity dataset, which revealed some key challenges of city" + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 47, + 673, + 269, + 693 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 673, + 269, + 693 + ], + "spans": [ + { + "bbox": [ + 47, + 673, + 269, + 693 + ], + "type": "text", + "content": "1https://www.unrealengine.com/marketplace/en-US/product/city-sample" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 59, + 693, + 165, + 703 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 693, + 165, + 703 + ], + "spans": [ + { + "bbox": [ + 59, + 693, + 165, + 703 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 59, + 693, + 165, + 703 + ], + "type": "text", + "content": "https://www.unrealengine.com/" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 59, + 703, + 223, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 703, + 223, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 703, + 223, + 712 + ], + "type": "text", + "content": "3https://www.unrealengine.com/en-US/eula/unreal" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3206" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 67, + 72, + 286, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 286, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 286, + 95 + ], + "type": "text", + "content": "scale neural rendering, and hopefully facilitate future research in this area." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 108, + 130, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 108, + 130, + 121 + ], + "spans": [ + { + "bbox": [ + 47, + 108, + 130, + 121 + ], + "type": "text", + "content": "2. Related work" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 128, + 253, + 141 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 128, + 253, + 141 + ], + "spans": [ + { + "bbox": [ + 47, + 128, + 253, + 141 + ], + "type": "text", + "content": "2.1. 3D Neural Representation at City Scale" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 147, + 286, + 326 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 147, + 286, + 326 + ], + "spans": [ + { + "bbox": [ + 47, + 147, + 286, + 326 + ], + "type": "text", + "content": "City-scale reconstruction has been studied for decades. Previous methods for representing geometry of a city mainly relied on raw point clouds acquired through either structure-from-motion [1] or Lidar sensors [12]. Recently, with the emergence of Neural Radiance Fields (NeRF) [22], novel view synthesis has become more efficient and effective. Numerous methods in this direction have further improved the speed [18, 28, 10, 23, 7] and accuracy [40, 3, 4] of reconstruction. NeRF is also used in a wide range of applications beyond novel view synthesis, such as inverse rendering [5, 27, 42, 26], surface reconstruction [34, 36, 2, 38] or HDR synthesis [11, 14, 21]. Although these methods demonstrate acceptable performance with small objects, grappling with urban scenes remains a significant challenge due to the limited representation capability of NeRF." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 327, + 286, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 327, + 286, + 601 + ], + "spans": [ + { + "bbox": [ + 47, + 327, + 286, + 601 + ], + "type": "text", + "content": "Based on these observations, recent methods were proposed for reconstructing radiance fields in urban-scale scenes. NeRF-W [20] captured per-image appearance variations and separated the entire scene into static and transient components, enabling the modeling of unstructured collections of in-the-wild photographs. Block-NeRF [30] extended NeRF-W [20] to model an neighborhood of San Francisco by dividing up urban environments into individually small Block-NeRFs. Mega-NeRF [33] also adopted the advantages of NeRF-W [20] and Block-NeRF [30] by first decomposing large-scale fly-view scenes into small spatial cells and then training these cells in parallel. Urban Radiance Fields [25] synthesized novel RGB images and extracted 3D surfaces from a combination of panoramicas and Lidar inputs in the urban environments. BungeeNeRF [37] introduced progressive modeling with multi-level supervision to handle city-scale data with varying levels of detail. Despite the progress made by the aforementioned methods [20, 30, 33, 25, 37], there is no unified dataset for evaluating these methods due to their varying settings. Significant challenge still remains in the city reconstruction problem, particularly in integrating aerial data and street-level data with varying levels of detail." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 610, + 252, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 610, + 252, + 623 + ], + "spans": [ + { + "bbox": [ + 47, + 610, + 252, + 623 + ], + "type": "text", + "content": "2.2. NeRF-based Datasets and Benchmarks" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 629, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 629, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 629, + 286, + 713 + ], + "type": "text", + "content": "Several benchmarks based on NeRF are proposed in the recent two years, which focus on the effective and better reconstruction of single objects [22, 18, 13], indoor scenes [9], or outdoor unbounded scenes [4, 15]. While there have been some good attempts to collect high-quality large-scale datasets using high-precision acquisition equipment [8, 17, 30, 19] as shown in Table 1, the high acquisition" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 72, + 545, + 395 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 395 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 395 + ], + "type": "text", + "content": "costs limit their size and scale. Some datasets are limited to only a few independent scenes that are far from urban-scale or are not fully open-source due to privacy and commercial reasons. For instance, Mill 19 dataset [33] only includes two suburban-like scenes, and the Quak 6D [8] and OMMO [19] datasets focus on a limited number of independent scenes that are not city-scale. Waymo Block-NeRF [30] dataset only grants access to 100 seconds of driving data and Urban Scene3D dataset [17] only releases two real-world scenarios. Additionally, existing real-world datasets commonly provide only one type of image data, such as street-level or aerial imagery, which makes modeling buildings incomplete [17, 19]. Collecting real data in outdoor scenes poses significant challenges due to difficulties in controlling environmental factors such as pedestrian movement, weather, and lighting. As a result, a standard and comprehensive benchmark for city-scale neural rendering has not yet been established. Existing outdoor NeRF-based benchmarks like OMMO [19] are too trivial to explore and analyze the urban implicit scene representation. To address these issues, we developed a plugin in Unreal Engine 5 to easily collect aerial and street city data with ground-truth camera poses. We built a city-scale and multitasking dataset that includes both fly-view and street-view images and propose a new city-scale benchmark for neural rendering. We also provided a detailed analysis of the challenges and opportunities of NeRF in urban environments." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 403, + 420, + 417 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 403, + 420, + 417 + ], + "spans": [ + { + "bbox": [ + 306, + 403, + 420, + 417 + ], + "type": "text", + "content": "3. MatrixCity Dataset" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 424, + 545, + 556 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 424, + 545, + 556 + ], + "spans": [ + { + "bbox": [ + 304, + 424, + 545, + 556 + ], + "type": "text", + "content": "The MatrixCity dataset aims to introduce a new challenging benchmark to the field of city-scale neural rendering by providing comprehensive city maps consisting of both aerial and street-level data. In addition to RGB images, we also offer normal, depth, and decomposed reflectance properties to support other tasks. Moreover, we can flexibly control environmental factors, including light direction and intensity, fog density, and human or vehicle crowding, to enable simulating real-world dynamic situations. Sec 3.1 describes our data construction procedure. Sec 3.2 and 3.3 provide detailed statistics and characteristics of this dataset." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 561, + 427, + 573 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 561, + 427, + 573 + ], + "spans": [ + { + "bbox": [ + 306, + 561, + 427, + 573 + ], + "type": "text", + "content": "3.1. Dataset Construction" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": "City Data Collection. Densely captured 2D images with sufficient multi-view supervision are required to learn a faithful scene geometry, especially for large city scenes. Collecting a sufficient amount of data in Unreal Engine 5 for city scenes is a complex process that requires adjusting camera trajectories to capture specific viewpoints. Although the Unreal Engine 5 offers a movie render queue plugin for high-quality image rendering, it can be time-consuming and inflexible to manually set up the position, rotation, and frame number of key points. For urban settings, it is not practical to manually set camera trajectories" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3207" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 75, + 72, + 212, + 180 + ], + "blocks": [ + { + "bbox": [ + 75, + 72, + 212, + 180 + ], + "lines": [ + { + "bbox": [ + 75, + 72, + 212, + 180 + ], + "spans": [ + { + "bbox": [ + 75, + 72, + 212, + 180 + ], + "type": "image", + "image_path": "dba1b9a66b17b62fe7ae27698d59970b39418182f6f1f7d4601c45c036acac6d.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 102, + 187, + 182, + 198 + ], + "lines": [ + { + "bbox": [ + 102, + 187, + 182, + 198 + ], + "spans": [ + { + "bbox": [ + 102, + 187, + 182, + 198 + ], + "type": "text", + "content": "(a) Aerial block splits" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 227, + 74, + 367, + 180 + ], + "blocks": [ + { + "bbox": [ + 227, + 74, + 367, + 180 + ], + "lines": [ + { + "bbox": [ + 227, + 74, + 367, + 180 + ], + "spans": [ + { + "bbox": [ + 227, + 74, + 367, + 180 + ], + "type": "image", + "image_path": "c0dd721ca974d0114370666b42366b01b072db2d002ca382c15a372bc817864a.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 238, + 187, + 349, + 198 + ], + "lines": [ + { + "bbox": [ + 238, + 187, + 349, + 198 + ], + "spans": [ + { + "bbox": [ + 238, + 187, + 349, + 198 + ], + "type": "text", + "content": "(b) Aerial trajectory in block 4" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 221, + 547, + 247 + ], + "lines": [ + { + "bbox": [ + 46, + 221, + 547, + 247 + ], + "spans": [ + { + "bbox": [ + 46, + 221, + 547, + 247 + ], + "type": "text", + "content": "Figure 2: Illustration of data collection in the small city in Unreal Engine 5. (a) Aerial block split for the entire small city; (b&c) Camera aerial and street trajectory of block 4 (visualized in bird-eye views) used in our plugin for data collection." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 383, + 74, + 521, + 178 + ], + "blocks": [ + { + "bbox": [ + 383, + 74, + 521, + 178 + ], + "lines": [ + { + "bbox": [ + 383, + 74, + 521, + 178 + ], + "spans": [ + { + "bbox": [ + 383, + 74, + 521, + 178 + ], + "type": "image", + "image_path": "a96c06da27a4398104f48b26fe15eed2cc98e434f62112eb732c6819bb26dee7.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 398, + 187, + 509, + 198 + ], + "lines": [ + { + "bbox": [ + 398, + 187, + 509, + 198 + ], + "spans": [ + { + "bbox": [ + 398, + 187, + 509, + 198 + ], + "type": "text", + "content": "(c) Street trajectory in block 4" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 267, + 287, + 339 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 267, + 287, + 339 + ], + "spans": [ + { + "bbox": [ + 46, + 267, + 287, + 339 + ], + "type": "text", + "content": "in a city-scale environment. To address this, we developed a plugin that automatically generates camera trajectories, reducing the need for manual annotation and increasing the efficiency of data collection. Camera trajectories generated by our plugins can be rendered in any Unreal Engine 5 scenes." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 341, + 288, + 520 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 341, + 288, + 520 + ], + "spans": [ + { + "bbox": [ + 46, + 341, + 288, + 520 + ], + "type": "text", + "content": "For aerial-view collection, we divide the city map into 10 blocks based on building heights (Figure 2 (a)) to better capture the building details. We provide the height of every collected block in the supplementary material. Note that current neural scene representations are generally suitable for bounded scenes, where scenes with large variation in height may cast great difficulty for accurate ray sampling. We then generate trajectories using the input of camera height and the four vertices' coordinates of the corresponding block (Figure 2 (b)) Our plugin puts four cameras at each capturing location, with each camera rotating " + }, + { + "bbox": [ + 46, + 341, + 288, + 520 + ], + "type": "inline_equation", + "content": "90^{\\circ}" + }, + { + "bbox": [ + 46, + 341, + 288, + 520 + ], + "type": "text", + "content": " apart from each other in the yaw direction and identical pitch values. The pitch value for the floor area is " + }, + { + "bbox": [ + 46, + 341, + 288, + 520 + ], + "type": "inline_equation", + "content": "-45^{\\circ}" + }, + { + "bbox": [ + 46, + 341, + 288, + 520 + ], + "type": "text", + "content": ", while it is " + }, + { + "bbox": [ + 46, + 341, + 288, + 520 + ], + "type": "inline_equation", + "content": "-60^{\\circ}" + }, + { + "bbox": [ + 46, + 341, + 288, + 520 + ], + "type": "text", + "content": " for high-rise area as there are more occlusions at higher levels." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 522, + 288, + 713 + ], + "type": "text", + "content": "For street-view data collection, we manually annotate the start and end points of each road and use them as inputs to generate straight-line trajectories with our plugin. We position six perspective cameras at each capturing location to render a cube map, providing a comprehensive view of the surroundings. Note that the cube map can be naturally transformed into panorama images, which are suitable for capturing the street views as much as possible with limited camera positions. Figure 2 (c) shows the resulting street-level trajectories for a specific block. Our plugin saves the generated camera trajectories as sequence assets of Unreal Engine, which can be easily reused to render images with different environmental settings. We will enhance our plugin to support more complex camera trajectories in the future, enabling us to generate even higher quality city-scale data. Note that we adapt auto-exposure to collect data. If" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 267, + 546, + 315 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 267, + 546, + 315 + ], + "spans": [ + { + "bbox": [ + 304, + 267, + 546, + 315 + ], + "type": "text", + "content": "we use the same fixed exposure for two types of data, the street views will be under-exposed while the aerial views will be over-exposed. HDR images will be included in the future." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 323, + 547, + 634 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 323, + 547, + 634 + ], + "spans": [ + { + "bbox": [ + 304, + 323, + 547, + 634 + ], + "type": "text", + "content": "Quality Control. To build a high-quality dataset for city-scale neural rendering, we utilize several mechanisms to ensure that the rendered images are of high quality and that the camera poses are accurate. Rather than using the more efficient real-time rendering pipeline, which often produces flickering images, we use the movie render queue plugin to render images with movie-level standards. Additionally, we set the Engine Scalability Settings to the best, turn off the motion blur and use anti-aliasing during the rendering process to achieve the highest possible image quality. We inspect the images thoroughly after rendering to remove any aerial views that look outside the map boundaries and ensure that there are no object clippings. Unreal Engine 5 provides ground-truth camera poses, which we have further verified through additional experiments to ensure their accuracy. Even with a small set of street data, training the MipNeRF-360 [4] model yields almost perfect novel view synthesis results, as demonstrated in Figure 6. This confirms the accurate annotation of our camera poses. Overall, by adopting these mechanisms, we ensure that the Matrix-City dataset provides high-quality images with precise camera poses, which is crucial for city-scale neural rendering research. Without considering noises like inaccurate pose and motion blur, we intend to gain more insights about the intrinsic challenges of city scenes since isolating these noises from real data is generally infeasible." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 641, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 547, + 715 + ], + "type": "text", + "content": "Dynamic Environments. The City Sample project of Unreal Engine 5 provides a plethora of powerful functions that allow for the creation of dynamic city scenes. As shown in Figure 1, we have the ability to control the presence of moving people and cars in the scene, adding to the realism of the environment. Additionally, we can quantitatively adjust" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3208" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 48, + 70, + 548, + 242 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 548, + 242 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 548, + 242 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 548, + 242 + ], + "type": "image", + "image_path": "1aaf2d2e8e3bdd8980447958fc7762a6d08ceb2cbf9ca763f4d66dc3c975311e.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 261, + 547, + 285 + ], + "lines": [ + { + "bbox": [ + 46, + 261, + 547, + 285 + ], + "spans": [ + { + "bbox": [ + 46, + 261, + 547, + 285 + ], + "type": "text", + "content": "Figure 3: Illustration of controlling dynamic environment factors in Unreal Engine 5 such as illumination (a), fog density (b) and decomposed reflectance (c)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 307, + 289, + 438 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 307, + 289, + 438 + ], + "spans": [ + { + "bbox": [ + 46, + 307, + 289, + 438 + ], + "type": "text", + "content": "the angle and intensity of the lighting to emulate the natural changes in light throughout a day, as demonstrated in Figure 3(a). We can also control the amount of fog in a scene, as shown in Figure 3(b), providing another quantitative tool for enhancing realism. Taken together, these functions allow for the simulation of almost all basic dynamic situations found in the real world. In addition, general camera noises like motion blur and defocus blur shown in Figure 4 can be simulated in Unreal Engine. Such varying lighting, weather conditions, moving objects and camera noises will lead to more realistic and accurate city-scale neural rendering." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 443, + 289, + 563 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 443, + 289, + 563 + ], + "spans": [ + { + "bbox": [ + 46, + 443, + 289, + 563 + ], + "type": "text", + "content": "Multiple Properties. Figure 1 (c) and Figure 3 (c) illustrates the various intermediate products generated by Unreal Engine during the rendering process, including depth, normal, and decomposed components (diffuse, specular, metallic, and roughness). These attributes are especially important for studies on inverse rendering and semantic analysis, which are popular for city scene analysis. Our plugin offers the ability to extract these properties without incurring any additional costs, which can be prohibitively expensive to obtain in real-world scenarios." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 574, + 151, + 586 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 574, + 151, + 586 + ], + "spans": [ + { + "bbox": [ + 47, + 574, + 151, + 586 + ], + "type": "text", + "content": "3.2. Dataset Statistics" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": "The MatrixCity dataset comprises two scenes from the City Sample project: Small City covering an area of " + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "2.7km^2" + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": " and Big City spanning " + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "25.3km^2" + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": ". In total, we collect 67k aerial images and 452k street-level images to ensure comprehensive coverage. As shown in Table 1, many of current datasets [17, 8, 19] do not offer the dense image captures of the whole city but small-size independent scenes. Although Waymo Block-NeRF [30] dataset densely collects an area of approximately " + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "inline_equation", + "content": "960m \\times 570m" + }, + { + "bbox": [ + 46, + 594, + 289, + 715 + ], + "type": "text", + "content": ", it only contains street data and results in the reconstructed buildings incom" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 307, + 547, + 415 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 307, + 547, + 415 + ], + "spans": [ + { + "bbox": [ + 304, + 307, + 547, + 415 + ], + "type": "text", + "content": "plete. All the existing datasets do not have quantitatively controllable environments including light, weather and human and car crowds, nor multiple properties like normal, depth, the decomposed reflectance components, etc, which restricts the in-depth study of city-scale neural rendering in dynamic scenes and other extension tasks. KITTI-360 [16], NuScenes [6], Waymo Open [29] are not designed for neural rendering purposes and only provide limited camera viewpoints." + } + ] + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 309, + 425, + 547, + 504 + ], + "blocks": [ + { + "bbox": [ + 309, + 425, + 547, + 504 + ], + "lines": [ + { + "bbox": [ + 309, + 425, + 547, + 504 + ], + "spans": [ + { + "bbox": [ + 309, + 425, + 547, + 504 + ], + "type": "image", + "image_path": "b5e3952916ea6f7b44b92747901e77d66c457413e12a681ae6ca37c745ec2cc0.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 306, + 525, + 545, + 537 + ], + "lines": [ + { + "bbox": [ + 306, + 525, + 545, + 537 + ], + "spans": [ + { + "bbox": [ + 306, + 525, + 545, + 537 + ], + "type": "text", + "content": "Figure 4: Examples of camera motion blur and defocus blur." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 558, + 440, + 570 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 558, + 440, + 570 + ], + "spans": [ + { + "bbox": [ + 306, + 558, + 440, + 570 + ], + "type": "text", + "content": "3.3. Dataset Characteristics" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 578, + 547, + 699 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 578, + 547, + 699 + ], + "spans": [ + { + "bbox": [ + 304, + 578, + 547, + 699 + ], + "type": "text", + "content": "High Quality. For constructing MatrixCity dataset, we use the City Sample project and the movie-level plugin named movie render queue of the Unreal Engine 5 which is demonstrated to reproduce The Matrix Awakens. Unlike games, the rendering process is not real-time and costs huge computations with pre-defined camera poses. Such movie-level rendering quality enables the collection of realistic city-scale data similar to the real world with fully dynamic environment factors. Vigorous quality control is performed during its collection phase." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 701, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 701, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 306, + 701, + 545, + 714 + ], + "type": "text", + "content": "Large-scale and Diversity. The City Sample project of Un" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3209" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 70, + 547, + 195 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 547, + 195 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 547, + 195 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 547, + 195 + ], + "type": "table", + "html": "
Dataset#ImagesLevelTypesSourceLightingHuman/CarWeatherD-Reflectance
UrbanScene3D [17]128KSceneAerialSynthetic & RealXXXX
Quad 6K [8]5.1KSceneAerialRealXXXX
Mill 19 [33]3.6KSceneAerialRealXXXX
Waymo Block-NeRF [30]12KCityStreetReal✓XXX
OMMO [19]14.7KSceneAerialReal✓XXX
KITTI-360 [16]300KCityStreetRealX✓XX
NuScenes [6]1.4MCityStreetReal✓✓✓X
Waymo Open [29]1MCityStreetReal✓✓✓X
Ours519kCityAerial+StreetSynthetic✓✓✓✓
", + "image_path": "7d1ec882faa43eea7db01784cf3cc2b69c3077894122d603fa5f2bc6689b3caf.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 50, + 227, + 545, + 299 + ], + "blocks": [ + { + "bbox": [ + 88, + 204, + 504, + 216 + ], + "lines": [ + { + "bbox": [ + 88, + 204, + 504, + 216 + ], + "spans": [ + { + "bbox": [ + 88, + 204, + 504, + 216 + ], + "type": "text", + "content": "Table 1: Comparison of statistics and properties between our MatrixCity dataset with previous datasets." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 227, + 545, + 299 + ], + "lines": [ + { + "bbox": [ + 50, + 227, + 545, + 299 + ], + "spans": [ + { + "bbox": [ + 50, + 227, + 545, + 299 + ], + "type": "table", + "html": "
BlockNeRF [22]DVGO [28]TensoRF [7]Instant-NGP [23]MipNeRF-360 [4]Average Height
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
Block_A23.150.5610.64925.040.6770.52025.960.7200.46227.210.7930.37626.640.7720.406150
Block_B22.940.6130.48522.720.6490.46324.950.7760.32625.450.8260.27124.800.7650.352432
Block_C22.150.5900.52721.390.6490.47524.110.7540.37023.210.7880.31124.200.7590.365419
Block_D23.090.5700.54824.140.6560.48624.990.7120.41626.240.7850.33826.450.7900.338250
Block_E23.530.6120.53424.740.7040.46725.660.7490.40826.360.8070.33526.540.8110.338200
Overall22.970.5890.54823.610.6670.48225.130.7620.39625.690.8000.32625.730.7790.360279
", + "image_path": "1454fe48ebdc391575187d6e79f1a05deb4d3acf2345dd0e28f61a67392c5cb2.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 307, + 545, + 319 + ], + "lines": [ + { + "bbox": [ + 47, + 307, + 545, + 319 + ], + "spans": [ + { + "bbox": [ + 47, + 307, + 545, + 319 + ], + "type": "text", + "content": "Table 2: Performance comparison of representative neural rendering methods on the aerial data of our MatrixCity benchmark." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 340, + 288, + 425 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 340, + 288, + 425 + ], + "spans": [ + { + "bbox": [ + 46, + 340, + 288, + 425 + ], + "type": "text", + "content": "real Engine 5 includes two cities with a large-scale coverage, which captures varying buildings, pedestrians, signs, vehicles, and lighting conditions, resulting in more diverse and realistic outdoor scenes that are representative of real-world cities. This ensures that researchers have access to a broad range of data to train their models on, leading to more accurate and effective city-scale neural rendering." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 433, + 287, + 540 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 433, + 287, + 540 + ], + "spans": [ + { + "bbox": [ + 46, + 433, + 287, + 540 + ], + "type": "text", + "content": "Controllable Environments. Unlike the real world data, we could control the lighting angle and intensity, the density and height of fog, and the density of flow of pedestrians and vehicles in a fine-grained manner. This flexibility enables us to generate dynamic scenarios of city scenes that would be difficult to capture in real-world data. This level of control over the environment allows for more detailed exploration of how different factors influence the training process of city-scale neural rendering." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 548, + 287, + 632 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 548, + 287, + 632 + ], + "spans": [ + { + "bbox": [ + 46, + 548, + 287, + 632 + ], + "type": "text", + "content": "Multiple Properties. Our developed plugin is able to extract additional information such as depth, normal and the decomposed reflectance components with minimum extra cost in Unreal Engine 5. This information supports additional tasks such as depth estimation, inverse rendering, which cannot be supported by real-world data without excessive labor." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 641, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 288, + 713 + ], + "type": "text", + "content": "Applications. By exploring neural rendering models on MatrixCity, we can transfer the algorithms to real-world urban scenes, which can generate scene for games, virtual reality, automatic driving, and so on. The rendered scenes can also make the interactions with digital humans possible in the metaverse." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 339, + 387, + 353 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 339, + 387, + 353 + ], + "spans": [ + { + "bbox": [ + 306, + 339, + 387, + 353 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 360, + 545, + 420 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 360, + 545, + 420 + ], + "spans": [ + { + "bbox": [ + 304, + 360, + 545, + 420 + ], + "type": "text", + "content": "In this section, we mainly investigate the quality of reconstruction and novel view rendering, and reveal the challenges of adapting existing SOTA methods on this task. Additional studies (e.g., dynamics scenes, lighting control, etc.) are provided in the supplementary material." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 431, + 430, + 443 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 431, + 430, + 443 + ], + "spans": [ + { + "bbox": [ + 306, + 431, + 430, + 443 + ], + "type": "text", + "content": "4.1. Datasets and Metrics." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": "MatrixCity benchmark. The MatrixCity dataset contains two city maps: Small City and Big City. According to the common practice in surveying and mapping that adjacent images should have an overlap of " + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "inline_equation", + "content": "70\\% - 80\\%" + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": ", we set a camera capture location every " + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "inline_equation", + "content": "40\\mathrm{m}" + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": " for aerial data collection and " + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "inline_equation", + "content": "5\\mathrm{m}" + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": " for street data collection. Small City includes 6k aerial images and 30k street-level images, while Big City has " + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "inline_equation", + "content": "60\\mathrm{k}" + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": " aerial images and " + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "inline_equation", + "content": "286\\mathrm{k}" + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": " street-level images. Note that we remove the aerial images that look outside the map boundary manually. Also, we remove the street images that look straight down following nerfstudio [31], which crops the bottom " + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "inline_equation", + "content": "20\\%" + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": " of the 360 images to reduce useless information. The ratio of training set to testing set is 8:1. To ensure both completeness of training perspectives and generalization ability in testing, test set is collected separately with no location overlap with the training set. For aerial data, the yaw direction randoms from " + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "inline_equation", + "content": "0^{\\circ}" + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "inline_equation", + "content": "360^{\\circ}" + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": " and the pitch direction randoms from " + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "inline_equation", + "content": "-60^{\\circ}" + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "inline_equation", + "content": "-45^{\\circ}" + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": ", and every camera location captures 1 image. For street data, the yaw direction randoms from " + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "inline_equation", + "content": "0^{\\circ}" + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "inline_equation", + "content": "90^{\\circ}" + }, + { + "bbox": [ + 304, + 450, + 547, + 715 + ], + "type": "text", + "content": " and every camera location captures 5 images, whose pitch and roll direction keep the same with the training set. Since the street data" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 316, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 316, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 316, + 757 + ], + "type": "text", + "content": "3210" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 83, + 143, + 125 + ], + "blocks": [ + { + "bbox": [ + 91, + 74, + 100, + 81 + ], + "lines": [ + { + "bbox": [ + 91, + 74, + 100, + 81 + ], + "spans": [ + { + "bbox": [ + 91, + 74, + 100, + 81 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 49, + 83, + 143, + 125 + ], + "lines": [ + { + "bbox": [ + 49, + 83, + 143, + 125 + ], + "spans": [ + { + "bbox": [ + 49, + 83, + 143, + 125 + ], + "type": "image", + "image_path": "a2d6f57608e675e78379d5ead5c87581a9d97f8f795ddb315597e45ffc6376a5.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 149, + 83, + 242, + 125 + ], + "blocks": [ + { + "bbox": [ + 190, + 74, + 200, + 81 + ], + "lines": [ + { + "bbox": [ + 190, + 74, + 200, + 81 + ], + "spans": [ + { + "bbox": [ + 190, + 74, + 200, + 81 + ], + "type": "text", + "content": "(b)" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 149, + 83, + 242, + 125 + ], + "lines": [ + { + "bbox": [ + 149, + 83, + 242, + 125 + ], + "spans": [ + { + "bbox": [ + 149, + 83, + 242, + 125 + ], + "type": "image", + "image_path": "7efc69beb5066bf13d8c1f8f7fe8ef82267b6132cd0d525e4f0dbc72982e441b.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 249, + 83, + 343, + 125 + ], + "blocks": [ + { + "bbox": [ + 291, + 74, + 300, + 81 + ], + "lines": [ + { + "bbox": [ + 291, + 74, + 300, + 81 + ], + "spans": [ + { + "bbox": [ + 291, + 74, + 300, + 81 + ], + "type": "text", + "content": "(c)" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 249, + 83, + 343, + 125 + ], + "lines": [ + { + "bbox": [ + 249, + 83, + 343, + 125 + ], + "spans": [ + { + "bbox": [ + 249, + 83, + 343, + 125 + ], + "type": "image", + "image_path": "52d526dd38275ecbdd4c3aed1b1558d91cc8aa4e8b0e25e93013c4ee4dcdc618.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 349, + 83, + 443, + 125 + ], + "blocks": [ + { + "bbox": [ + 391, + 74, + 400, + 81 + ], + "lines": [ + { + "bbox": [ + 391, + 74, + 400, + 81 + ], + "spans": [ + { + "bbox": [ + 391, + 74, + 400, + 81 + ], + "type": "text", + "content": "(d)" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 349, + 83, + 443, + 125 + ], + "lines": [ + { + "bbox": [ + 349, + 83, + 443, + 125 + ], + "spans": [ + { + "bbox": [ + 349, + 83, + 443, + 125 + ], + "type": "image", + "image_path": "ac7c6bf44ffb6fff2627945aaedb66d3dc74c32eda2de31519d1ce08e2c511bd.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 450, + 83, + 544, + 125 + ], + "blocks": [ + { + "bbox": [ + 493, + 74, + 501, + 82 + ], + "lines": [ + { + "bbox": [ + 493, + 74, + 501, + 82 + ], + "spans": [ + { + "bbox": [ + 493, + 74, + 501, + 82 + ], + "type": "text", + "content": "(e)" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 450, + 83, + 544, + 125 + ], + "lines": [ + { + "bbox": [ + 450, + 83, + 544, + 125 + ], + "spans": [ + { + "bbox": [ + 450, + 83, + 544, + 125 + ], + "type": "image", + "image_path": "1813f822a44f559611da00862e23003591e3b19d2d7d677e02f375d425ae54a6.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 49, + 129, + 143, + 172 + ], + "blocks": [ + { + "bbox": [ + 49, + 129, + 143, + 172 + ], + "lines": [ + { + "bbox": [ + 49, + 129, + 143, + 172 + ], + "spans": [ + { + "bbox": [ + 49, + 129, + 143, + 172 + ], + "type": "image", + "image_path": "173e59d390a78f1d9d69cb754a988b12682306dbcb8752b37003019d37878b04.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 149, + 129, + 242, + 172 + ], + "blocks": [ + { + "bbox": [ + 149, + 129, + 242, + 172 + ], + "lines": [ + { + "bbox": [ + 149, + 129, + 242, + 172 + ], + "spans": [ + { + "bbox": [ + 149, + 129, + 242, + 172 + ], + "type": "image", + "image_path": "3baee1e69fd85e034b3f8d235b8afe23a98a5c7b00d5ed17b164e76207319149.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 249, + 130, + 343, + 173 + ], + "blocks": [ + { + "bbox": [ + 249, + 130, + 343, + 173 + ], + "lines": [ + { + "bbox": [ + 249, + 130, + 343, + 173 + ], + "spans": [ + { + "bbox": [ + 249, + 130, + 343, + 173 + ], + "type": "image", + "image_path": "cc3f57e98e3b2ad5c6d5ed1bff31cdc9a59a46609d6e78543b25f8125a4c8643.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 349, + 129, + 443, + 172 + ], + "blocks": [ + { + "bbox": [ + 349, + 129, + 443, + 172 + ], + "lines": [ + { + "bbox": [ + 349, + 129, + 443, + 172 + ], + "spans": [ + { + "bbox": [ + 349, + 129, + 443, + 172 + ], + "type": "image", + "image_path": "b3e25edfb77ad005a815d3bf031608e309d278bac5adca17224a7a06f133aecd.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 450, + 129, + 544, + 172 + ], + "blocks": [ + { + "bbox": [ + 450, + 129, + 544, + 172 + ], + "lines": [ + { + "bbox": [ + 450, + 129, + 544, + 172 + ], + "spans": [ + { + "bbox": [ + 450, + 129, + 544, + 172 + ], + "type": "image", + "image_path": "a1a50fd0d26136aadc0a924e8463884a11b3eb1ac58e3d9ee4f1481e945d51c3.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 49, + 176, + 143, + 219 + ], + "blocks": [ + { + "bbox": [ + 49, + 176, + 143, + 219 + ], + "lines": [ + { + "bbox": [ + 49, + 176, + 143, + 219 + ], + "spans": [ + { + "bbox": [ + 49, + 176, + 143, + 219 + ], + "type": "image", + "image_path": "79b2dc24e1d250ceb72897e93fc73767d98f70a954ef5d6ac09628a55175b33c.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 149, + 176, + 242, + 219 + ], + "blocks": [ + { + "bbox": [ + 149, + 176, + 242, + 219 + ], + "lines": [ + { + "bbox": [ + 149, + 176, + 242, + 219 + ], + "spans": [ + { + "bbox": [ + 149, + 176, + 242, + 219 + ], + "type": "image", + "image_path": "4c310fb0e91d88429ca7c324eaa847d61b0839f0a8ea58ddd9733c19a444879f.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 249, + 176, + 343, + 219 + ], + "blocks": [ + { + "bbox": [ + 249, + 176, + 343, + 219 + ], + "lines": [ + { + "bbox": [ + 249, + 176, + 343, + 219 + ], + "spans": [ + { + "bbox": [ + 249, + 176, + 343, + 219 + ], + "type": "image", + "image_path": "66c6eb2cbb21e8630657c63ca89d6a11c9e39e4d72015cebbdcbf426c5f398db.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 349, + 175, + 443, + 218 + ], + "blocks": [ + { + "bbox": [ + 349, + 175, + 443, + 218 + ], + "lines": [ + { + "bbox": [ + 349, + 175, + 443, + 218 + ], + "spans": [ + { + "bbox": [ + 349, + 175, + 443, + 218 + ], + "type": "image", + "image_path": "db4e6e40e4198f57cb5d9752cd4c7c7eb6e97c4971e0aed54ef5e73431321aa5.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 450, + 175, + 544, + 218 + ], + "blocks": [ + { + "bbox": [ + 450, + 175, + 544, + 218 + ], + "lines": [ + { + "bbox": [ + 450, + 175, + 544, + 218 + ], + "spans": [ + { + "bbox": [ + 450, + 175, + 544, + 218 + ], + "type": "image", + "image_path": "1711fba39d6a4b55cf609d004aec26cdeca75f69e9cb812dc4a019a37afc0d5f.jpg" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_body" + } + ], + "index": 19 + }, + { + "type": "image", + "bbox": [ + 49, + 223, + 143, + 265 + ], + "blocks": [ + { + "bbox": [ + 49, + 223, + 143, + 265 + ], + "lines": [ + { + "bbox": [ + 49, + 223, + 143, + 265 + ], + "spans": [ + { + "bbox": [ + 49, + 223, + 143, + 265 + ], + "type": "image", + "image_path": "a37d26131b6638166dbe2630e902b341cbf9e8e5ac795846ee50f50214112cec.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + } + ], + "index": 20 + }, + { + "type": "image", + "bbox": [ + 149, + 223, + 242, + 265 + ], + "blocks": [ + { + "bbox": [ + 149, + 223, + 242, + 265 + ], + "lines": [ + { + "bbox": [ + 149, + 223, + 242, + 265 + ], + "spans": [ + { + "bbox": [ + 149, + 223, + 242, + 265 + ], + "type": "image", + "image_path": "a506bdf0e33bf58c600353d7628583392f73bf814ee68f686c56a4f9fa53549a.jpg" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_body" + } + ], + "index": 21 + }, + { + "type": "image", + "bbox": [ + 249, + 222, + 343, + 264 + ], + "blocks": [ + { + "bbox": [ + 249, + 222, + 343, + 264 + ], + "lines": [ + { + "bbox": [ + 249, + 222, + 343, + 264 + ], + "spans": [ + { + "bbox": [ + 249, + 222, + 343, + 264 + ], + "type": "image", + "image_path": "9a9aee706fc4a8b55126bbf59915f49eace32ae5a8dcf0f9a30e3a6ce3a7a919.jpg" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_body" + } + ], + "index": 22 + }, + { + "type": "image", + "bbox": [ + 349, + 222, + 443, + 264 + ], + "blocks": [ + { + "bbox": [ + 349, + 222, + 443, + 264 + ], + "lines": [ + { + "bbox": [ + 349, + 222, + 443, + 264 + ], + "spans": [ + { + "bbox": [ + 349, + 222, + 443, + 264 + ], + "type": "image", + "image_path": "1ae01777f307d7c415f7fbf05cf39cf67bcbc11497c54b0d00833a6d9238f4af.jpg" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_body" + } + ], + "index": 23 + }, + { + "type": "image", + "bbox": [ + 450, + 222, + 544, + 264 + ], + "blocks": [ + { + "bbox": [ + 450, + 222, + 544, + 264 + ], + "lines": [ + { + "bbox": [ + 450, + 222, + 544, + 264 + ], + "spans": [ + { + "bbox": [ + 450, + 222, + 544, + 264 + ], + "type": "image", + "image_path": "eb7cf7b07977e8bff84813ccf5a2da69805288033ee1e79c1124a6064b1335ef.jpg" + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_body" + } + ], + "index": 24 + }, + { + "type": "image", + "bbox": [ + 49, + 270, + 143, + 312 + ], + "blocks": [ + { + "bbox": [ + 49, + 270, + 143, + 312 + ], + "lines": [ + { + "bbox": [ + 49, + 270, + 143, + 312 + ], + "spans": [ + { + "bbox": [ + 49, + 270, + 143, + 312 + ], + "type": "image", + "image_path": "f415401d89c9534bfebd6ae89ca9ebd3f3e1666c1d1dc20125047f1cacfc7e52.jpg" + } + ] + } + ], + "index": 25, + "angle": 0, + "type": "image_body" + } + ], + "index": 25 + }, + { + "type": "image", + "bbox": [ + 149, + 270, + 242, + 312 + ], + "blocks": [ + { + "bbox": [ + 149, + 270, + 242, + 312 + ], + "lines": [ + { + "bbox": [ + 149, + 270, + 242, + 312 + ], + "spans": [ + { + "bbox": [ + 149, + 270, + 242, + 312 + ], + "type": "image", + "image_path": "ffd2c28d94582a153dc45750b939397ee5e831f8be52f406923c154e6390bd06.jpg" + } + ] + } + ], + "index": 26, + "angle": 0, + "type": "image_body" + } + ], + "index": 26 + }, + { + "type": "image", + "bbox": [ + 249, + 270, + 343, + 312 + ], + "blocks": [ + { + "bbox": [ + 249, + 270, + 343, + 312 + ], + "lines": [ + { + "bbox": [ + 249, + 270, + 343, + 312 + ], + "spans": [ + { + "bbox": [ + 249, + 270, + 343, + 312 + ], + "type": "image", + "image_path": "df5f8b3f1dd503685f0ca65e6fe4d272478bef06c5001516c64b570b58ba8803.jpg" + } + ] + } + ], + "index": 27, + "angle": 0, + "type": "image_body" + } + ], + "index": 27 + }, + { + "type": "image", + "bbox": [ + 349, + 269, + 443, + 311 + ], + "blocks": [ + { + "bbox": [ + 349, + 269, + 443, + 311 + ], + "lines": [ + { + "bbox": [ + 349, + 269, + 443, + 311 + ], + "spans": [ + { + "bbox": [ + 349, + 269, + 443, + 311 + ], + "type": "image", + "image_path": "9e574bf958c0afa6d5a39fb992bbbe7ebc49de439a64ea0a8cf01bf0ffb99881.jpg" + } + ] + } + ], + "index": 28, + "angle": 0, + "type": "image_body" + } + ], + "index": 28 + }, + { + "type": "image", + "bbox": [ + 450, + 269, + 544, + 311 + ], + "blocks": [ + { + "bbox": [ + 450, + 269, + 544, + 311 + ], + "lines": [ + { + "bbox": [ + 450, + 269, + 544, + 311 + ], + "spans": [ + { + "bbox": [ + 450, + 269, + 544, + 311 + ], + "type": "image", + "image_path": "579f264aa39dcd92dec537a98d9a4776ecb4942167873289564431404306e9ae.jpg" + } + ] + } + ], + "index": 29, + "angle": 0, + "type": "image_body" + } + ], + "index": 29 + }, + { + "type": "image", + "bbox": [ + 49, + 317, + 143, + 359 + ], + "blocks": [ + { + "bbox": [ + 49, + 317, + 143, + 359 + ], + "lines": [ + { + "bbox": [ + 49, + 317, + 143, + 359 + ], + "spans": [ + { + "bbox": [ + 49, + 317, + 143, + 359 + ], + "type": "image", + "image_path": "1b5d6d54acaa2e4b773c3421b05c284fd627d498991eee280e06e4aff32968ff.jpg" + } + ] + } + ], + "index": 30, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 379, + 546, + 403 + ], + "lines": [ + { + "bbox": [ + 46, + 379, + 546, + 403 + ], + "spans": [ + { + "bbox": [ + 46, + 379, + 546, + 403 + ], + "type": "text", + "content": "Figure 5: Visualization of novel view synthesis results of previous representative large-scale neural rendering methods on the aerial data of our MatrixCity dataset." + } + ] + } + ], + "index": 35, + "angle": 0, + "type": "image_caption" + } + ], + "index": 30 + }, + { + "type": "image", + "bbox": [ + 149, + 318, + 242, + 359 + ], + "blocks": [ + { + "bbox": [ + 149, + 318, + 242, + 359 + ], + "lines": [ + { + "bbox": [ + 149, + 318, + 242, + 359 + ], + "spans": [ + { + "bbox": [ + 149, + 318, + 242, + 359 + ], + "type": "image", + "image_path": "549c1711a84823d51881ebe1ad93c3ee94cac82ceb5abb8f2f47452b8e48f90b.jpg" + } + ] + } + ], + "index": 31, + "angle": 0, + "type": "image_body" + } + ], + "index": 31 + }, + { + "type": "image", + "bbox": [ + 249, + 316, + 343, + 357 + ], + "blocks": [ + { + "bbox": [ + 249, + 316, + 343, + 357 + ], + "lines": [ + { + "bbox": [ + 249, + 316, + 343, + 357 + ], + "spans": [ + { + "bbox": [ + 249, + 316, + 343, + 357 + ], + "type": "image", + "image_path": "6f3dcfc6c6f3319fa39f11396a88bdb2d7bae36ece2204779a2dd6250b2e8a93.jpg" + } + ] + } + ], + "index": 32, + "angle": 0, + "type": "image_body" + } + ], + "index": 32 + }, + { + "type": "image", + "bbox": [ + 349, + 316, + 443, + 357 + ], + "blocks": [ + { + "bbox": [ + 349, + 316, + 443, + 357 + ], + "lines": [ + { + "bbox": [ + 349, + 316, + 443, + 357 + ], + "spans": [ + { + "bbox": [ + 349, + 316, + 443, + 357 + ], + "type": "image", + "image_path": "37a42ec35a471a3b507fc727123d918c110a7e9580483b8e3f6efddad7b7d93c.jpg" + } + ] + } + ], + "index": 33, + "angle": 0, + "type": "image_body" + } + ], + "index": 33 + }, + { + "type": "image", + "bbox": [ + 450, + 316, + 544, + 357 + ], + "blocks": [ + { + "bbox": [ + 450, + 316, + 544, + 357 + ], + "lines": [ + { + "bbox": [ + 450, + 316, + 544, + 357 + ], + "spans": [ + { + "bbox": [ + 450, + 316, + 544, + 357 + ], + "type": "image", + "image_path": "617755d21edb6d2768be99db15ae50462d6c9aecfb42bb751a43fbe9f0b5126e.jpg" + } + ] + } + ], + "index": 34, + "angle": 0, + "type": "image_body" + } + ], + "index": 34 + }, + { + "bbox": [ + 46, + 425, + 287, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 425, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 46, + 425, + 287, + 533 + ], + "type": "text", + "content": "contains more details, we also ablate the street data collection density in Table 4, which demonstrates that grid-based method is more sensitive to data density than MLP-based NeRF method. Additionally, we provide a super dense version street data with " + }, + { + "bbox": [ + 46, + 425, + 287, + 533 + ], + "type": "inline_equation", + "content": "135k" + }, + { + "bbox": [ + 46, + 425, + 287, + 533 + ], + "type": "text", + "content": " for Small City with " + }, + { + "bbox": [ + 46, + 425, + 287, + 533 + ], + "type": "inline_equation", + "content": "1\\mathrm{m}" + }, + { + "bbox": [ + 46, + 425, + 287, + 533 + ], + "type": "text", + "content": " interval. For demonstrative purpose, we conducted experiments on the Small City in this stage, where the interval between adjacent frames is " + }, + { + "bbox": [ + 46, + 425, + 287, + 533 + ], + "type": "inline_equation", + "content": "5\\mathrm{m}" + }, + { + "bbox": [ + 46, + 425, + 287, + 533 + ], + "type": "text", + "content": " for street data. We will release the data splits of the following sections." + } + ] + } + ], + "index": 36 + }, + { + "bbox": [ + 46, + 538, + 287, + 610 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 538, + 287, + 610 + ], + "spans": [ + { + "bbox": [ + 46, + 538, + 287, + 610 + ], + "type": "text", + "content": "Evaluation metric. We evaluate the rendering performance of each baseline method based on PSNR(Peak Signal-to-Noise Ratio), SSIM(Structural Similarity) [35] and the VGG implementation of LPIPS [41]. And we also use mean angular error (MAE) and mean squared error (MSE) to evaluate estimated normal vectors and depth map, respectively." + } + ] + } + ], + "index": 37 + }, + { + "bbox": [ + 47, + 621, + 115, + 633 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 621, + 115, + 633 + ], + "spans": [ + { + "bbox": [ + 47, + 621, + 115, + 633 + ], + "type": "text", + "content": "4.2. Baselines." + } + ] + } + ], + "index": 38 + }, + { + "bbox": [ + 46, + 642, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 288, + 715 + ], + "type": "text", + "content": "We aim to test the performance of current neural rendering methods on the MatrixCity dataset to explore the challenges for city-scale neural rendering. To achieve this, we choose five widely recognized methods: NeRF [22], DVGO [28], Instant-NGP [23], TensoRF [7] and MipNeRF-360 [4]. Note that we all use the official implementation of" + } + ] + } + ], + "index": 39 + }, + { + "bbox": [ + 304, + 425, + 546, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 425, + 546, + 544 + ], + "spans": [ + { + "bbox": [ + 304, + 425, + 546, + 544 + ], + "type": "text", + "content": "these baselines except NeRF and Instant-NGP. For NeRF we use the widely recognized Pytorch version [39]. And for Instant-NGP, we use the open-source version [24]. We find that ngp-pl [24] generally performs better than torch-ngp [32]. To address the challenge of increasingly intricate urban content, we recognized the limited capacity of the original baseline models. So we increased the number of parameters to handle more complex urban environments. Specific details regarding these parameter increases can be found in the supplementary material." + } + ] + } + ], + "index": 40 + }, + { + "bbox": [ + 306, + 552, + 485, + 564 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 552, + 485, + 564 + ], + "spans": [ + { + "bbox": [ + 306, + 552, + 485, + 564 + ], + "type": "text", + "content": "4.3. Neural Rendering on Aerial Data" + } + ] + } + ], + "index": 41 + }, + { + "bbox": [ + 304, + 570, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 547, + 713 + ], + "type": "text", + "content": "Due to the limitations of current methods and models, it is impractical to use a single model to represent an entire map. Therefore, we divided the map into five blocks based on building height and coverage area. Each block covers a roughly homogeneous area, where buildings within each block have similar heights. Our results, shown in Table 2, indicate that MipNeRF-360 [4] and Instant-NGP [23] perform better, while NeRF [22] performs the worst. This indicates that grid-based methods and MLP-based NeRF methods both can model the block-size aerial data modeling well. Despite scaling up the NeRF model significantly, its ability to model large-scale scenes remains limited, as illus" + } + ] + } + ], + "index": 42 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "3211" + } + ] + } + ], + "index": 43 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 80, + 69, + 154, + 144 + ], + "blocks": [ + { + "bbox": [ + 64, + 140, + 78, + 152 + ], + "lines": [ + { + "bbox": [ + 64, + 140, + 78, + 152 + ], + "spans": [ + { + "bbox": [ + 64, + 140, + 78, + 152 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 80, + 69, + 154, + 144 + ], + "lines": [ + { + "bbox": [ + 80, + 69, + 154, + 144 + ], + "spans": [ + { + "bbox": [ + 80, + 69, + 154, + 144 + ], + "type": "image", + "image_path": "1d742d12e9c0410fa15d8e19d54b454245993da18287585a8264f38d71d47653.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 157, + 69, + 231, + 144 + ], + "blocks": [ + { + "bbox": [ + 157, + 69, + 231, + 144 + ], + "lines": [ + { + "bbox": [ + 157, + 69, + 231, + 144 + ], + "spans": [ + { + "bbox": [ + 157, + 69, + 231, + 144 + ], + "type": "image", + "image_path": "85c7c5453911f599d9aba15eaf3888231c0fbde9fe4f86a0ab6ecbaf7703c389.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 233, + 69, + 307, + 144 + ], + "blocks": [ + { + "bbox": [ + 233, + 69, + 307, + 144 + ], + "lines": [ + { + "bbox": [ + 233, + 69, + 307, + 144 + ], + "spans": [ + { + "bbox": [ + 233, + 69, + 307, + 144 + ], + "type": "image", + "image_path": "ea301d09e8c836347eee1fe36022888121a8d92468635add68398b027f8639df.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 309, + 69, + 383, + 144 + ], + "blocks": [ + { + "bbox": [ + 309, + 69, + 383, + 144 + ], + "lines": [ + { + "bbox": [ + 309, + 69, + 383, + 144 + ], + "spans": [ + { + "bbox": [ + 309, + 69, + 383, + 144 + ], + "type": "image", + "image_path": "7e252dcf15a63c9ce0d61a5cd16640c65b8e185a51af50bb376890e8c8fb526e.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 384, + 69, + 459, + 144 + ], + "blocks": [ + { + "bbox": [ + 384, + 69, + 459, + 144 + ], + "lines": [ + { + "bbox": [ + 384, + 69, + 459, + 144 + ], + "spans": [ + { + "bbox": [ + 384, + 69, + 459, + 144 + ], + "type": "image", + "image_path": "20cd175cf3e827499c97bee41ddf3a7ed8dbd7649ff2aae195efdba49fc1d48a.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 460, + 69, + 534, + 144 + ], + "blocks": [ + { + "bbox": [ + 460, + 69, + 534, + 144 + ], + "lines": [ + { + "bbox": [ + 460, + 69, + 534, + 144 + ], + "spans": [ + { + "bbox": [ + 460, + 69, + 534, + 144 + ], + "type": "image", + "image_path": "3ecc2a8dd5583dc74c115f6dbc47863eebcb0415fc36e3abb740b73ab76bd5be.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 81, + 145, + 154, + 220 + ], + "blocks": [ + { + "bbox": [ + 81, + 145, + 154, + 220 + ], + "lines": [ + { + "bbox": [ + 81, + 145, + 154, + 220 + ], + "spans": [ + { + "bbox": [ + 81, + 145, + 154, + 220 + ], + "type": "image", + "image_path": "963851ea9510586eaaca935d44076b40df54d7ef4885c132d9fd07a2a89e7d21.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 157, + 145, + 231, + 220 + ], + "blocks": [ + { + "bbox": [ + 157, + 145, + 231, + 220 + ], + "lines": [ + { + "bbox": [ + 157, + 145, + 231, + 220 + ], + "spans": [ + { + "bbox": [ + 157, + 145, + 231, + 220 + ], + "type": "image", + "image_path": "d4a15c217187980974811195f011504bbd160d2d42dc9a5274d6a3f9b41fd62d.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 233, + 145, + 306, + 220 + ], + "blocks": [ + { + "bbox": [ + 233, + 145, + 306, + 220 + ], + "lines": [ + { + "bbox": [ + 233, + 145, + 306, + 220 + ], + "spans": [ + { + "bbox": [ + 233, + 145, + 306, + 220 + ], + "type": "image", + "image_path": "1c3963cef3df740d8dff5badcf21b73dd0adeb3204539f0b372119b5fb9cb8ea.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 309, + 145, + 383, + 220 + ], + "blocks": [ + { + "bbox": [ + 309, + 145, + 383, + 220 + ], + "lines": [ + { + "bbox": [ + 309, + 145, + 383, + 220 + ], + "spans": [ + { + "bbox": [ + 309, + 145, + 383, + 220 + ], + "type": "image", + "image_path": "83a43b889525f885c77e5e87c9ef883bcb7df74d44f3bc23a04defc490d3d69c.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 384, + 145, + 459, + 220 + ], + "blocks": [ + { + "bbox": [ + 384, + 145, + 459, + 220 + ], + "lines": [ + { + "bbox": [ + 384, + 145, + 459, + 220 + ], + "spans": [ + { + "bbox": [ + 384, + 145, + 459, + 220 + ], + "type": "image", + "image_path": "09813853e540994a7e5a0a9c64674d2a577ad254da8b66aa86b3c1b9c29f167e.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 460, + 145, + 534, + 220 + ], + "blocks": [ + { + "bbox": [ + 460, + 145, + 534, + 220 + ], + "lines": [ + { + "bbox": [ + 460, + 145, + 534, + 220 + ], + "spans": [ + { + "bbox": [ + 460, + 145, + 534, + 220 + ], + "type": "image", + "image_path": "2b2317974bd35ea44fee18d23954ba79dc1e750c55aaf1ed30bdb9ba1471350c.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 81, + 224, + 154, + 298 + ], + "blocks": [ + { + "bbox": [ + 81, + 224, + 154, + 298 + ], + "lines": [ + { + "bbox": [ + 81, + 224, + 154, + 298 + ], + "spans": [ + { + "bbox": [ + 81, + 224, + 154, + 298 + ], + "type": "image", + "image_path": "d9c576c21877bbde15f8f912c8067f2cea2b291e598cc14506519a58fc32eaa9.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 65, + 294, + 79, + 306 + ], + "lines": [ + { + "bbox": [ + 65, + 294, + 79, + 306 + ], + "spans": [ + { + "bbox": [ + 65, + 294, + 79, + 306 + ], + "type": "text", + "content": "(b)" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 157, + 224, + 230, + 298 + ], + "blocks": [ + { + "bbox": [ + 157, + 224, + 230, + 298 + ], + "lines": [ + { + "bbox": [ + 157, + 224, + 230, + 298 + ], + "spans": [ + { + "bbox": [ + 157, + 224, + 230, + 298 + ], + "type": "image", + "image_path": "3509b280d211d4234bfff1efbfb8ff00b54c7a56939466c61276925fc7e43acb.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 232, + 224, + 306, + 298 + ], + "blocks": [ + { + "bbox": [ + 232, + 224, + 306, + 298 + ], + "lines": [ + { + "bbox": [ + 232, + 224, + 306, + 298 + ], + "spans": [ + { + "bbox": [ + 232, + 224, + 306, + 298 + ], + "type": "image", + "image_path": "98c26496069b00204e2da4e11920f9902c48110c542312a974ec59374e4e2279.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 309, + 224, + 382, + 298 + ], + "blocks": [ + { + "bbox": [ + 309, + 224, + 382, + 298 + ], + "lines": [ + { + "bbox": [ + 309, + 224, + 382, + 298 + ], + "spans": [ + { + "bbox": [ + 309, + 224, + 382, + 298 + ], + "type": "image", + "image_path": "34340dc01f89c9d061aefe735091503edfbb2de3428a78f87797313c08d9b69f.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 384, + 224, + 459, + 298 + ], + "blocks": [ + { + "bbox": [ + 384, + 224, + 459, + 298 + ], + "lines": [ + { + "bbox": [ + 384, + 224, + 459, + 298 + ], + "spans": [ + { + "bbox": [ + 384, + 224, + 459, + 298 + ], + "type": "image", + "image_path": "95fcef5302b62294f9ad3588ef0271ba02d0460cfbf40f92b575e50c969079de.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 460, + 224, + 534, + 298 + ], + "blocks": [ + { + "bbox": [ + 460, + 224, + 534, + 298 + ], + "lines": [ + { + "bbox": [ + 460, + 224, + 534, + 298 + ], + "spans": [ + { + "bbox": [ + 460, + 224, + 534, + 298 + ], + "type": "image", + "image_path": "8933a8085e59e2873a802ba9215767cbb1d696fb355ba8e7caaacb99c4b648af.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 81, + 300, + 154, + 373 + ], + "blocks": [ + { + "bbox": [ + 81, + 300, + 154, + 373 + ], + "lines": [ + { + "bbox": [ + 81, + 300, + 154, + 373 + ], + "spans": [ + { + "bbox": [ + 81, + 300, + 154, + 373 + ], + "type": "image", + "image_path": "e13ae1d51cf0a6f24e9a51932e68338f5ef8619c218583018fa72388db71891e.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 392, + 546, + 418 + ], + "lines": [ + { + "bbox": [ + 46, + 392, + 546, + 418 + ], + "spans": [ + { + "bbox": [ + 46, + 392, + 546, + 418 + ], + "type": "text", + "content": "Figure 6: Visualization of novel view synthesis of city-scale neural rendering methods on (a) Block_Small and (b) Block_A of street-view data. MLP-based NeRF methods suffer from capacity issues while grid-based baselines show severe artifacts." + } + ] + } + ], + "index": 26, + "angle": 0, + "type": "image_caption" + } + ], + "index": 20 + }, + { + "type": "image", + "bbox": [ + 157, + 300, + 230, + 373 + ], + "blocks": [ + { + "bbox": [ + 157, + 300, + 230, + 373 + ], + "lines": [ + { + "bbox": [ + 157, + 300, + 230, + 373 + ], + "spans": [ + { + "bbox": [ + 157, + 300, + 230, + 373 + ], + "type": "image", + "image_path": "b1e2248edbfef02751cd85e2f0cacbbc6677ec4aa28c93e593e2aaf4c06dc5ed.jpg" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_body" + } + ], + "index": 21 + }, + { + "type": "image", + "bbox": [ + 232, + 300, + 306, + 373 + ], + "blocks": [ + { + "bbox": [ + 232, + 300, + 306, + 373 + ], + "lines": [ + { + "bbox": [ + 232, + 300, + 306, + 373 + ], + "spans": [ + { + "bbox": [ + 232, + 300, + 306, + 373 + ], + "type": "image", + "image_path": "ac43ab54fe24535bc1def9c954a45e1d86328f8aefe2fa7d2f144c69023cf702.jpg" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_body" + } + ], + "index": 22 + }, + { + "type": "image", + "bbox": [ + 309, + 300, + 383, + 373 + ], + "blocks": [ + { + "bbox": [ + 309, + 300, + 383, + 373 + ], + "lines": [ + { + "bbox": [ + 309, + 300, + 383, + 373 + ], + "spans": [ + { + "bbox": [ + 309, + 300, + 383, + 373 + ], + "type": "image", + "image_path": "8e4a2483c4d3dcb4b13b6472c620676497196b3d9c6de0f31a1a3026c9d38d1c.jpg" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_body" + } + ], + "index": 23 + }, + { + "type": "image", + "bbox": [ + 384, + 300, + 459, + 373 + ], + "blocks": [ + { + "bbox": [ + 384, + 300, + 459, + 373 + ], + "lines": [ + { + "bbox": [ + 384, + 300, + 459, + 373 + ], + "spans": [ + { + "bbox": [ + 384, + 300, + 459, + 373 + ], + "type": "image", + "image_path": "596d72b347a1d36a7d1beef47bcd470b5d0a5810b226d9b6c37ad0fc33347438.jpg" + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_body" + } + ], + "index": 24 + }, + { + "type": "image", + "bbox": [ + 460, + 300, + 534, + 373 + ], + "blocks": [ + { + "bbox": [ + 460, + 300, + 534, + 373 + ], + "lines": [ + { + "bbox": [ + 460, + 300, + 534, + 373 + ], + "spans": [ + { + "bbox": [ + 460, + 300, + 534, + 373 + ], + "type": "image", + "image_path": "3843696584c6256335a80f8a85b576f4c0b4e9b683fde1107f2ffb02edfb5a6e.jpg" + } + ] + } + ], + "index": 25, + "angle": 0, + "type": "image_body" + } + ], + "index": 25 + }, + { + "type": "table", + "bbox": [ + 50, + 429, + 545, + 478 + ], + "blocks": [ + { + "bbox": [ + 50, + 429, + 545, + 478 + ], + "lines": [ + { + "bbox": [ + 50, + 429, + 545, + 478 + ], + "spans": [ + { + "bbox": [ + 50, + 429, + 545, + 478 + ], + "type": "table", + "html": "
BlockNeRF [22]DVGO [28]TensoRF [7]Instant-NGP [23]MipNeRF-360 [4]
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
Block_A20.120.6010.62620.470.6170.60420.930.6430.57721.960.7120.49322.000.7170.488
Block_Small22.150.6780.51122.100.7110.45422.950.7410.44522.840.7450.40824.470.8270.297
Overall21.140.6400.56921.290.6640.52921.940.6920.51122.400.7290.45123.240.7720.393
", + "image_path": "2164062a13e0ee57cf7bd058abe268d4147a3ea3a72dd61b9c639e34f0464b18.jpg" + } + ] + } + ], + "index": 27, + "angle": 0, + "type": "table_body" + } + ], + "index": 27 + }, + { + "bbox": [ + 46, + 520, + 287, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 520, + 287, + 604 + ], + "spans": [ + { + "bbox": [ + 46, + 520, + 287, + 604 + ], + "type": "text", + "content": "trated in Figure 5. Additionally, we found that the high-rise area is more challenging to model than the floor area. In the high-rise area, there are numerous occlusions between the buildings, which is a significant challenge for aerial data modeling. From Figure 5, we can observe that current methods still struggle to accurately model small objects and reflective buildings." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 47, + 611, + 224, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 611, + 224, + 624 + ], + "spans": [ + { + "bbox": [ + 47, + 611, + 224, + 624 + ], + "type": "text", + "content": "4.4. Neural Rendering on Street Data" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 46, + 629, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 288, + 713 + ], + "type": "text", + "content": "We first run all these baselines on the street data of Block_A and find that all the methods perform much worse than the results of the aerial data, especially for the grid-based methods, as shown in Table 3. Street data contains much more details than aerial data, and it is harder to achieve high-quality results on street data than on aerial data, which is also demonstrated in Figure 7. Thus we" + } + ] + } + ], + "index": 31 + }, + { + "type": "table", + "bbox": [ + 309, + 518, + 545, + 592 + ], + "blocks": [ + { + "bbox": [ + 47, + 487, + 545, + 499 + ], + "lines": [ + { + "bbox": [ + 47, + 487, + 545, + 499 + ], + "spans": [ + { + "bbox": [ + 47, + 487, + 545, + 499 + ], + "type": "text", + "content": "Table 3: Performance comparison of representative neural rendering methods on the street data of our MatrixCity benchmark." + } + ] + } + ], + "index": 28, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 309, + 518, + 545, + 592 + ], + "lines": [ + { + "bbox": [ + 309, + 518, + 545, + 592 + ], + "spans": [ + { + "bbox": [ + 309, + 518, + 545, + 592 + ], + "type": "table", + "html": "
DensityInstant-NGP [23]MipNeRF-360 [4]
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
5.0 m21.4360.7330.40227.750.8660.2956
3.6 m24.9780.8030.35029.3660.8840.280
2.0 m30.0250.8850.23531.4200.9010.265
1.0 m32.4440.9120.21131.8580.9050.263
0.5 m32.9990.9210.20232.2100.9070.261
", + "image_path": "3b66f5656f0ba854051a9f03573df5cda5cc7c3630bf09922f0ee3ca4f92060b.jpg" + } + ] + } + ], + "index": 32, + "angle": 0, + "type": "table_body" + } + ], + "index": 32 + }, + { + "bbox": [ + 305, + 600, + 545, + 625 + ], + "lines": [ + { + "bbox": [ + 305, + 600, + 545, + 625 + ], + "spans": [ + { + "bbox": [ + 305, + 600, + 545, + 625 + ], + "type": "text", + "content": "Table 4: Ablation on the density of street data collection on our MatrixCity benchmark." + } + ] + } + ], + "index": 33, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 305, + 653, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 653, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 305, + 653, + 547, + 715 + ], + "type": "text", + "content": "conclude that modeling the street data of a block-size area in a single model is not reasonable and filter a crossroad data to test current methods, called Block_Small. Analyzed the results on Block_Small, we find that the MLP-based NeRF methods perform better than the grid-based methods," + } + ] + } + ], + "index": 34 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3212" + } + ] + } + ], + "index": 35 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 59, + 71, + 202, + 155 + ], + "blocks": [ + { + "bbox": [ + 59, + 71, + 202, + 155 + ], + "lines": [ + { + "bbox": [ + 59, + 71, + 202, + 155 + ], + "spans": [ + { + "bbox": [ + 59, + 71, + 202, + 155 + ], + "type": "image", + "image_path": "ce057f5f6de5fd137029ecf8a4048d7ba25f851518d0081a8d09449885650996.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 96, + 175, + 496, + 188 + ], + "lines": [ + { + "bbox": [ + 96, + 175, + 496, + 188 + ], + "spans": [ + { + "bbox": [ + 96, + 175, + 496, + 188 + ], + "type": "text", + "content": "Figure 7: Visualization of the depth and normal results of MipNeRF-360 on aerial and street views." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 203, + 72, + 349, + 156 + ], + "blocks": [ + { + "bbox": [ + 203, + 72, + 349, + 156 + ], + "lines": [ + { + "bbox": [ + 203, + 72, + 349, + 156 + ], + "spans": [ + { + "bbox": [ + 203, + 72, + 349, + 156 + ], + "type": "image", + "image_path": "eeeff59462180ae1570f354b02dbc2ad0f3e3308c580d5cd7a8ea1624ed5da0c.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 355, + 72, + 441, + 156 + ], + "blocks": [ + { + "bbox": [ + 355, + 72, + 441, + 156 + ], + "lines": [ + { + "bbox": [ + 355, + 72, + 441, + 156 + ], + "spans": [ + { + "bbox": [ + 355, + 72, + 441, + 156 + ], + "type": "image", + "image_path": "c9f2e25d9bd2a66cd45541f475823b27f857ba4d4cd365f5577088d09d1d7ae3.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 443, + 72, + 528, + 156 + ], + "blocks": [ + { + "bbox": [ + 443, + 72, + 528, + 156 + ], + "lines": [ + { + "bbox": [ + 443, + 72, + 528, + 156 + ], + "spans": [ + { + "bbox": [ + 443, + 72, + 528, + 156 + ], + "type": "image", + "image_path": "b661b6763d352115c560348063b162ee4e87fdf5b23af7a1de96b19c44e659a5.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 48, + 209, + 289, + 310 + ], + "blocks": [ + { + "bbox": [ + 48, + 209, + 289, + 310 + ], + "lines": [ + { + "bbox": [ + 48, + 209, + 289, + 310 + ], + "spans": [ + { + "bbox": [ + 48, + 209, + 289, + 310 + ], + "type": "image", + "image_path": "e416d48dae908559c4f6bebb7d888806d0b775821a1e1ceee538b97f8f9e9423.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 330, + 288, + 414 + ], + "lines": [ + { + "bbox": [ + 46, + 330, + 288, + 414 + ], + "spans": [ + { + "bbox": [ + 46, + 330, + 288, + 414 + ], + "type": "text", + "content": "Figure 8: Visualization of neural rendered results on aerial and street views before and after fusion of two types of views. Streets views are generally harder than aerial views to deliver high-quality rendering results, with notable floating artifacts, where the model get easily overfitting to the training views with cheated geometry. The naive joint training on the fused data downgrades the quality." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 49, + 424, + 287, + 479 + ], + "blocks": [ + { + "bbox": [ + 49, + 424, + 287, + 479 + ], + "lines": [ + { + "bbox": [ + 49, + 424, + 287, + 479 + ], + "spans": [ + { + "bbox": [ + 49, + 424, + 287, + 479 + ], + "type": "table", + "html": "
Data TypeTensoRF [7]MipNeRF-360 [4]
PSNR ↑SSIM ↑LPIPS ↓PSNR ↑SSIM ↑LPIPS ↓
Aerial27.260.8290.23128.370.8550.197
Streat22.100.7270.44923.050.8050.312
Fusion21.440.6560.50417.070.4700.600
", + "image_path": "a49a2b753aff4e660b8c1861ea7ab54b2e3cbd7e1f4c2c0611c09417a3fe14d7.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 487, + 287, + 513 + ], + "lines": [ + { + "bbox": [ + 46, + 487, + 287, + 513 + ], + "spans": [ + { + "bbox": [ + 46, + 487, + 287, + 513 + ], + "type": "text", + "content": "Table 5: Ablation on the fusion of aerial and street data on our MatrixCity benchmark." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 532, + 287, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 532, + 287, + 604 + ], + "spans": [ + { + "bbox": [ + 46, + 532, + 287, + 604 + ], + "type": "text", + "content": "which is also demonstrated in Figure 6. The Block_Small can also be seen as a 360 unbounded scenes with a distant background. Figure 6 shows that MipNeRF-360 can alleviate this problem to some extent. However, the reflective parts and fine-grained architectures are still not well reconstructed." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 611, + 262, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 611, + 262, + 624 + ], + "spans": [ + { + "bbox": [ + 47, + 611, + 262, + 624 + ], + "type": "text", + "content": "4.5. Neural Rendering on Joint Types of Data" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "content": "The major motivation to fuse data from both aerial and street view is to provide content information at different granularity. While aerial views are generally easier to train with less geometry ambiguities, it lacks many details on the near-ground, which are critical to deliver immersive experience for exploring a city. On the other hand, street-view images often only offer partial information about the scene" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 209, + 546, + 449 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 209, + 546, + 449 + ], + "spans": [ + { + "bbox": [ + 304, + 209, + 546, + 449 + ], + "type": "text", + "content": "revealing the local contents, which are sensitive to overfit to training views. We therefore explore to train the aerial and street data together, which cover the same area, aiming the leverage the advantage of two sources of data to ensure wide coverage as well as fine details. However, according to Table 5, we find that the performance of TensoRF [7] and MipNeRF-360 [4] both got worse after simply fusing the aerial and street data to train together. As shown in the Figure 8, the ground part of the aerial view becomes dirty after training with the street data for both methods. For the street view, the foreground of MipNeRF-360 becomes worse. We analyze that due to the significant difference in the level of details between street-level and aerial imagery, as well as the large disparity in distance from the foreground, it is challenging to train models simply by utilizing both types of data. We need to further investigate how algorithms can effectively utilize both the geometric information from aerial imagery and the detailed information from street-level imagery, such as finetuning, progressive training, separate group of hyperparameters, etc." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 459, + 379, + 471 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 459, + 379, + 471 + ], + "spans": [ + { + "bbox": [ + 306, + 459, + 379, + 471 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 479, + 546, + 609 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 479, + 546, + 609 + ], + "spans": [ + { + "bbox": [ + 304, + 479, + 546, + 609 + ], + "type": "text", + "content": "In this paper, we proposed MatrixCity, a high-quality and city-scale benchmark with diverse, controllable and realistic data collected from the powerful Unreal Engine 5. Additional information like depth and normal are also collected with minimum extra cost in our MatrixCity dataset, enables other potential tasks and applications like depth estimation and inverse rendering. On top of MatrixCity, we have empirically investigated representative methods on two types of data independently and the fusion of both aerial-view and street-view data. We hope these efforts could facilitate new advances in the field of city-scale neural rendering." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 610, + 547, + 706 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 610, + 547, + 706 + ], + "spans": [ + { + "bbox": [ + 304, + 610, + 547, + 706 + ], + "type": "text", + "content": "Acknowledgment This project is funded in part by Shanghai AI Laboratory (P23KS00020, 2022ZD0160201), CUHK Interdisciplinary AI Research Institute, and the Centre for Perceptual and Interactive Intelligence (CPII) Ltd under the Innovation and Technology Commission (ITC)'s InnoHK. We would like to thank Haiyi Mei and Lei Yang for their invaluable help and discussions for the plug-in development." + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3213" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 133 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 133 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 133 + ], + "type": "text", + "content": "[1] Sameer Agarwal, Yasutaka Furukawa, Noah Snavely, Ian Simon, Brian Curless, Steven M. Seitz, and Richard Szeliski. Building rome in a day. Commun. ACM, 54(10):105-112, 2011." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 136, + 287, + 168 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 136, + 287, + 168 + ], + "spans": [ + { + "bbox": [ + 53, + 136, + 287, + 168 + ], + "type": "text", + "content": "[2] Dejan Azinovic, Ricardo Martin-Brualla, Dan B. Goldman, Matthias Nießner, and Justus Thies. Neural RGB-D surface reconstruction. In CVPR, pages 6280-6291. IEEE, 2022." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 170, + 287, + 213 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 170, + 287, + 213 + ], + "spans": [ + { + "bbox": [ + 53, + 170, + 287, + 213 + ], + "type": "text", + "content": "[3] Jonathan T. Barron, Ben Mildenhall, Matthew Tancik, Peter Hedman, Ricardo Martin-Brualla, and Pratul P. Srinivasan. Mip-nerf: A multiscale representation for anti-aliasing neural radiance fields. In ICCV, pages 5835–5844. IEEE, 2021." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 214, + 287, + 256 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 214, + 287, + 256 + ], + "spans": [ + { + "bbox": [ + 53, + 214, + 287, + 256 + ], + "type": "text", + "content": "[4] Jonathan T. Barron, Ben Mildenhall, Dor Verbin, Pratul P. Srinivasan, and Peter Hedman. Mip-nerf 360: Unbounded anti-aliased neural radiance fields. In CVPR, pages 5460–5469. IEEE, 2022." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 258, + 287, + 301 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 258, + 287, + 301 + ], + "spans": [ + { + "bbox": [ + 53, + 258, + 287, + 301 + ], + "type": "text", + "content": "[5] Mark Boss, Raphael Braun, Varun Jampani, Jonathan T. Barron, Ce Liu, and Hendrik P. A. Lensch. Nerd: Neural reflectance decomposition from image collections. In ICCV, pages 12664-12674. IEEE, 2021." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 303, + 288, + 368 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 303, + 288, + 368 + ], + "spans": [ + { + "bbox": [ + 53, + 303, + 288, + 368 + ], + "type": "text", + "content": "[6] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giacarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 11621-11631, 2020." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 369, + 287, + 413 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 369, + 287, + 413 + ], + "spans": [ + { + "bbox": [ + 53, + 369, + 287, + 413 + ], + "type": "text", + "content": "[7] Anpei Chen, Zexiang Xu, Andreas Geiger, Jingyi Yu, and Hao Su. Tensorf: Tensorial radiance fields. In ECCV (32), volume 13692 of Lecture Notes in Computer Science, pages 333-350. Springer, 2022." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 415, + 287, + 456 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 415, + 287, + 456 + ], + "spans": [ + { + "bbox": [ + 53, + 415, + 287, + 456 + ], + "type": "text", + "content": "[8] David J. Crandall, Andrew Owens, Noah Snavely, and Daniel P. Huttenlocher. Sfm with mrfs: Discrete-continuous optimization for large-scale structure from motion. IEEE Trans. Pattern Anal. Mach. Intell., 35(12):2841-2853, 2013." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 458, + 287, + 502 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 458, + 287, + 502 + ], + "spans": [ + { + "bbox": [ + 53, + 458, + 287, + 502 + ], + "type": "text", + "content": "[9] Angela Dai, Angel X. Chang, Manolis Savva, Maciej Halber, Thomas A. Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In CVPR, pages 2432–2443. IEEE Computer Society, 2017." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 503, + 287, + 545 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 503, + 287, + 545 + ], + "spans": [ + { + "bbox": [ + 48, + 503, + 287, + 545 + ], + "type": "text", + "content": "[10] Sara Fridovich-Keil, Alex Yu, Matthew Tancik, Qinhong Chen, Benjamin Recht, and Angjoo Kanazawa. Plenoxels: Radiance fields without neural networks. In CVPR, pages 5491–5500. IEEE, 2022." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 547, + 287, + 590 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 547, + 287, + 590 + ], + "spans": [ + { + "bbox": [ + 48, + 547, + 287, + 590 + ], + "type": "text", + "content": "[11] Xin Huang, Qi Zhang, Ying Feng, Hongdong Li, Xuan Wang, and Qing Wang. Hdr-nerf: High dynamic range neural radiance fields. In CVPR, pages 18377-18387. IEEE, 2022." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 592, + 287, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 592, + 287, + 624 + ], + "spans": [ + { + "bbox": [ + 48, + 592, + 287, + 624 + ], + "type": "text", + "content": "[12] Veli Ilci and Charles K. Toth. High definition 3d map creation using gnss/imu/lidar sensor integration to support autonomous vehicle navigation. Sensors, 20(3):899, 2020." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 625, + 287, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 625, + 287, + 668 + ], + "spans": [ + { + "bbox": [ + 48, + 625, + 287, + 668 + ], + "type": "text", + "content": "[13] Rasmus Ramsbøl Jensen, Anders Lindbjerg Dahl, George Vogiatzis, Engin Tola, and Henrik Aanæs. Large scale multiview stereopsis evaluation. In CVPR, pages 406-413. IEEE Computer Society, 2014." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "type": "text", + "content": "[14] Kim Jun-Seong, Kim Yu-Ji, Moon Ye-Bin, and Tae-Hyun Oh. HDR-plenoxels: Self-calibrating high dynamic range radiance fields. In ECCV (32), volume 13692 of Lecture Notes in Computer Science, pages 384-401. Springer, 2022." + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 31, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 115 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 115 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 115 + ], + "type": "text", + "content": "[15] Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: benchmarking large-scale scene reconstruction. ACM Trans. Graph., 36(4):78:1-78:13, 2017." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 118, + 545, + 160 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 545, + 160 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 545, + 160 + ], + "type": "text", + "content": "[16] Yiyi Liao, Jun Xie, and Andreas Geiger. Kitti-360: A novel dataset and benchmarks for urban scene understanding in 2d and 3d. IEEE Transactions on Pattern Analysis and Machine Intelligence, 45(3):3292-3310, 2022." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 162, + 545, + 215 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 162, + 545, + 215 + ], + "spans": [ + { + "bbox": [ + 307, + 162, + 545, + 215 + ], + "type": "text", + "content": "[17] Liqiang Lin, Yilin Liu, Yue Hu, Xingguang Yan, Ke Xie, and Hui Huang. Capturing, reconstructing, and simulating: The urbanscene3d dataset. In ECCV (8), volume 13668 of Lecture Notes in Computer Science, pages 93-109. Springer, 2022." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 217, + 545, + 248 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 217, + 545, + 248 + ], + "spans": [ + { + "bbox": [ + 307, + 217, + 545, + 248 + ], + "type": "text", + "content": "[18] Lingjie Liu, Jiatao Gu, Kyaw Zaw Lin, Tat-Seng Chua, and Christian Theobalt. Neural sparse voxel fields. In NeurIPS, 2020." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 250, + 545, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 250, + 545, + 293 + ], + "spans": [ + { + "bbox": [ + 307, + 250, + 545, + 293 + ], + "type": "text", + "content": "[19] Chongshan Lu, Fukun Yin, Xin Chen, Tao Chen, Gang Yu, and Jiayuan Fan. A large-scale outdoor multi-modal dataset and benchmark for novel view synthesis and implicit scene reconstruction. CoRR, abs/2301.06782, 2023." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 294, + 545, + 347 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 294, + 545, + 347 + ], + "spans": [ + { + "bbox": [ + 307, + 294, + 545, + 347 + ], + "type": "text", + "content": "[20] Ricardo Martin-Brualla, Noha Radwan, Mehdi S. M. Sajjadi, Jonathan T. Barron, Alexey Dosovitskiy, and Daniel Duckworth. Nerf in the wild: Neural radiance fields for unconstrained photo collections. In CVPR, pages 7210-7219. IEEE, 2021." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 350, + 545, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 350, + 545, + 392 + ], + "spans": [ + { + "bbox": [ + 307, + 350, + 545, + 392 + ], + "type": "text", + "content": "[21] Ben Mildenhall, Peter Hedman, Ricardo Martin-Brualla, Pratul P. Srinivasan, and Jonathan T. Barron. Nerf in the dark: High dynamic range view synthesis from noisy raw images. In CVPR, pages 16169-16178. IEEE, 2022." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 394, + 545, + 448 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 394, + 545, + 448 + ], + "spans": [ + { + "bbox": [ + 307, + 394, + 545, + 448 + ], + "type": "text", + "content": "[22] Ben Mildenhall, Pratul P. Srinivasan, Matthew Tancik, Jonathan T. Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. In ECCV (1), volume 12346 of Lecture Notes in Computer Science, pages 405-421. Springer, 2020." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 449, + 545, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 449, + 545, + 491 + ], + "spans": [ + { + "bbox": [ + 307, + 449, + 545, + 491 + ], + "type": "text", + "content": "[23] Thomas Müller, Alex Evans, Christoph Schied, and Alexander Keller. Instant neural graphics primitives with a multiresolution hash encoding. ACM Trans. Graph., 41(4):102:1-102:15, 2022." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 493, + 545, + 514 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 493, + 545, + 514 + ], + "spans": [ + { + "bbox": [ + 307, + 493, + 545, + 514 + ], + "type": "text", + "content": "[24] Chen Quei-An. ngp pl: a pytorch-lightning implementation of instant-ngp, 2022. https://github.com/kwea123/ngp.pl." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 516, + 545, + 557 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 516, + 545, + 557 + ], + "spans": [ + { + "bbox": [ + 307, + 516, + 545, + 557 + ], + "type": "text", + "content": "[25] Konstantinos Rematas, Andrew Liu, Pratul P. Srinivasan, Jonathan T. Barron, Andrea Tagliasacchi, Thomas A. Funkhouser, and Vittorio Ferrari. Urban radiance fields. In CVPR, pages 12922-12932. IEEE, 2022." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 559, + 545, + 613 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 559, + 545, + 613 + ], + "spans": [ + { + "bbox": [ + 307, + 559, + 545, + 613 + ], + "type": "text", + "content": "[26] Viktor Rudnev, Mohamed Elgharib, William A. P. Smith, Lingjie Liu, Vladislav Golyanik, and Christian Theobalt. Nerf for outdoor scene relighting. In ECCV (16), volume 13676 of Lecture Notes in Computer Science, pages 615-631. Springer, 2022." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 615, + 545, + 658 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 615, + 545, + 658 + ], + "spans": [ + { + "bbox": [ + 307, + 615, + 545, + 658 + ], + "type": "text", + "content": "[27] Pratul P. Srinivasan, Boyang Deng, Xiuming Zhang, Matthew Tancik, Ben Mildenhall, and Jonathan T. Barron. Nerv: Neural reflectance and visibility fields for relighting and view synthesis. In CVPR, pages 7495-7504. IEEE, 2021." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 658, + 545, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 658, + 545, + 690 + ], + "spans": [ + { + "bbox": [ + 307, + 658, + 545, + 690 + ], + "type": "text", + "content": "[28] Cheng Sun, Min Sun, and Hwann-Tzong Chen. Direct voxel grid optimization: Super-fast convergence for radiance fields reconstruction. In CVPR, pages 5449-5459. IEEE, 2022." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 692, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 692, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 692, + 545, + 713 + ], + "type": "text", + "content": "[29] Pei Sun, Henrik Kretzschmar, Xerxes Dotiwalla, Aurelien Chouard, Vijaysai Patnaik, Paul Tsui, James Guo, Yin Zhou," + } + ] + } + ], + "index": 30 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3214" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 707 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 117 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 117 + ], + "type": "text", + "content": "Yuning Chai, Benjamin Caine, et al. Scalability in perception for autonomous driving: Waymo open dataset. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2446-2454, 2020." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 118, + 287, + 171 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 118, + 287, + 171 + ], + "spans": [ + { + "bbox": [ + 48, + 118, + 287, + 171 + ], + "type": "text", + "content": "[30] Matthew Tancik, Vincent Casser, Xinchen Yan, Sabeek Pradhan, Ben P. Mildenhall, Pratul P. Srinivasan, Jonathan T. Barron, and Henrik Kretzschmar. Block-nerf: Scalable large scene neural view synthesis. In CVPR, pages 8238–8248. IEEE, 2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 173, + 287, + 249 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 173, + 287, + 249 + ], + "spans": [ + { + "bbox": [ + 48, + 173, + 287, + 249 + ], + "type": "text", + "content": "[31] Matthew Tancik, Ethan Weber, Evonne Ng, Ruilong Li, Brent Yi, Justin Kerr, Terrance Wang, Alexander Kristoffersen, Jake Austin, Kamyar Salahi, Abhik Ahuja, David McAllister, and Angjoo Kanazawa. Nerfstudio: A modular framework for neural radiance field development. In ACM SIGGRAPH 2023 Conference Proceedings, SIGGRAPH '23, 2023." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 251, + 287, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 251, + 287, + 274 + ], + "spans": [ + { + "bbox": [ + 48, + 251, + 287, + 274 + ], + "type": "text", + "content": "[32] Jiaxiang Tang. Torch-ngp: a pytorch implementation of instant-ngp, 2022. https://github.com/ashawkey/torch-ngp." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 274, + 287, + 317 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 274, + 287, + 317 + ], + "spans": [ + { + "bbox": [ + 48, + 274, + 287, + 317 + ], + "type": "text", + "content": "[33] Haithem Turki, Deva Ramanan, and Mahadev Satyanarayanan. Mega-nerf: Scalable construction of large-scale nerfs for virtual fly- throughs. In CVPR, pages 12912-12921. IEEE, 2022." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 318, + 287, + 361 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 318, + 287, + 361 + ], + "spans": [ + { + "bbox": [ + 48, + 318, + 287, + 361 + ], + "type": "text", + "content": "[34] Peng Wang, Lingjie Liu, Yuan Liu, Christian Theobalt, Taku Komura, and Wenping Wang. Neus: Learning neural implicit surfaces by volume rendering for multi-view reconstruction. In NeurIPS, pages 27171-27183, 2021." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 363, + 287, + 406 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 363, + 287, + 406 + ], + "spans": [ + { + "bbox": [ + 48, + 363, + 287, + 406 + ], + "type": "text", + "content": "[35] Zhou Wang, Alan C. Bovik, Hamid R. Sheikh, and Eero P. Simoncelli. Image quality assessment: from error visibility to structural similarity. IEEE Trans. Image Process., 13(4):600-612, 2004." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 407, + 287, + 450 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 407, + 287, + 450 + ], + "spans": [ + { + "bbox": [ + 48, + 407, + 287, + 450 + ], + "type": "text", + "content": "[36] Tong Wu, Jiaqi Wang, Xingang Pan, Xudong Xu, Christian Theobalt, Ziwei Liu, and Dahua Lin. Voxurf: Voxel-based efficient and accurate neural surface reconstruction. CoRR, abs/2208.12697, 2022." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 452, + 287, + 518 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 452, + 287, + 518 + ], + "spans": [ + { + "bbox": [ + 48, + 452, + 287, + 518 + ], + "type": "text", + "content": "[37] Yuanbo Xiangli, Linning Xu, Xingang Pan, Nanxuan Zhao, Anyi Rao, Christian Theobalt, Bo Dai, and Dahua Lin. Bungeenerf: Progressive neural radiance field for extreme multi-scale scene rendering. In ECCV (32), volume 13692 of Lecture Notes in Computer Science, pages 106-122. Springer, 2022." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 519, + 287, + 551 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 519, + 287, + 551 + ], + "spans": [ + { + "bbox": [ + 48, + 519, + 287, + 551 + ], + "type": "text", + "content": "[38] Lior Yariv, Jiatao Gu, Yoni Kasten, and Yaron Lipman. Volume rendering of neural implicit surfaces. In NeurIPS, pages 4805-4815, 2021." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 552, + 287, + 574 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 552, + 287, + 574 + ], + "spans": [ + { + "bbox": [ + 48, + 552, + 287, + 574 + ], + "type": "text", + "content": "[39] Lin Yen-Chen. Nerf-pytorch. https://github.com/yenchenlin/nerf-pytorch/, 2020." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 575, + 287, + 607 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 575, + 287, + 607 + ], + "spans": [ + { + "bbox": [ + 48, + 575, + 287, + 607 + ], + "type": "text", + "content": "[40] Kai Zhang, Gernot Riegler, Noah Snavely, and Vladlen Koltun. Nerf++: Analyzing and improving neural radiance fields. CoRR, abs/2010.07492, 2020." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 609, + 287, + 651 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 609, + 287, + 651 + ], + "spans": [ + { + "bbox": [ + 48, + 609, + 287, + 651 + ], + "type": "text", + "content": "[41] Richard Zhang, Phillip Isola, Alexei A. Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In CVPR, pages 586-595. IEEE, 2018." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 653, + 287, + 707 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 653, + 287, + 707 + ], + "spans": [ + { + "bbox": [ + 48, + 653, + 287, + 707 + ], + "type": "text", + "content": "[42] Xiuming Zhang, Pratul P. Srinivasan, Boyang Deng, Paul E. Debevec, William T. Freeman, and Jonathan T. Barron. Nefactor: neural factorization of shape and reflectance under an unknown illumination. ACM Trans. Graph., 40(6):237:1-237:18, 2021." + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "3215" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/3d8f338d-7ad3-414d-a017-25b8e25151fd_content_list.json b/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/3d8f338d-7ad3-414d-a017-25b8e25151fd_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..beb1a9cdcbec249f28aa8a1e6bdb622f33f2829a --- /dev/null +++ b/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/3d8f338d-7ad3-414d-a017-25b8e25151fd_content_list.json @@ -0,0 +1,1500 @@ +[ + { + "type": "text", + "text": "MatrixVT: Efficient Multi-Camera to BEV Transformation for 3D Perception", + "text_level": 1, + "bbox": [ + 94, + 130, + 875, + 154 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Hongyu Zhou, Zheng Ge, Zeming Li, Xiangyu Zhang* MEGVII Technology", + "bbox": [ + 269, + 180, + 704, + 217 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{zhouhongyu, gezheng, lizeming, zhangxiangyu}@megvii.com", + "bbox": [ + 236, + 219, + 732, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 268, + 313, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "This paper proposes an efficient multi-camera to Bird's-Eye-View (BEV) view transformation method for 3D perception, dubbed MatrixVT. Existing view transformers either suffer from poor efficiency or rely on device-specific operators, hindering the broad application of BEV models. In contrast, our method generates BEV features efficiently with only convolutions and matrix multiplications (MatMul). Specifically, we propose describing the BEV feature as the MatMul of image feature and a sparse Feature Transporting Matrix (FTM). A Prime Extraction module is then introduced to compress the dimension of image features and reduce FTM's sparsity. Moreover, we propose the Ring & Ray Decomposition to replace the FTM with two matrices and reformulate our pipeline to reduce calculation further. Compared to existing methods, MatrixVT enjoys a faster speed and less memory footprint while remaining deploy-friendly. Extensive experiments on nuScenes and Waymo benchmarks demonstrate that our method is highly efficient but obtains results on par with the SOTA method in object detection and map segmentation tasks.", + "bbox": [ + 75, + 300, + 473, + 603 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 631, + 209, + 647 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Vision-centric 3D perception in Bird's-Eye-View (BEV) [17, 20, 24] has recently drawn extensive attention. Apart from their outstanding performance, the compact and unified feature representation in BEV facilitates straight-forward feature fusions [1, 5, 12, 10], and enables various downstream tasks (e.g. object detection [6, 9, 10], map segmentation [17, 30], motion planning, etc.) to be applied thereon easily.", + "bbox": [ + 75, + 656, + 468, + 777 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "View Transformation (VT) is the key component that converts multi-camera features to BEV, which has been heavily studied in previous works [15, 20, 17, 24, 10, 6, 21, 9]. Existing VT methods can be categorized into geometry-based [13, 19, 17, 9, 18, 30] and learning-based meth", + "bbox": [ + 75, + 777, + 470, + 854 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/fb432dea189edc91f47fda152fc823b97f4dc9a705573a076f8533d24976038c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 521, + 267, + 870, + 372 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/2ae6134179487d9f3d9d7dd0f488ca92d55bf898131976f820bc1c245eec3d8e.jpg", + "image_caption": [ + "Figure 1. The pipeline of Lift-Splat (upper) and our proposed MatrixVT (lower). We compress image features before VT to reduce memory footprint and calculation. Note that only standard operators are adopted in MatrixVT." + ], + "image_footnote": [], + "bbox": [ + 522, + 375, + 870, + 478 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "ods [10, 20, 15]. Among these two categories, geometry-based methods show superior performance due to the use of geometric constraints. Lift-Splat [17], as a representative geometry-based VT, predicts categorical depth distribution for each pixel and \"lift\" the corresponding features into 3D space according to the predicted depth. These feature vectors are then gathered into pre-defined grids on a reference BEV plane (i.e., \"splat\") to form the BEV feature (Fig. 1, upper). The Lift-Splat-based VT has shown great potential to produce high-quality BEV features, achieving remarkable performance on object detection [9, 5] and map segmentation tasks.", + "bbox": [ + 496, + 566, + 893, + 747 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Despite the effectiveness of Lift-Splat-like VT [9], two issues remain. First, the \"splat\" operation is not universally feasible. Existing implementations of \"splat\" relies on either the \"cumsum trick\" [17, 6] that is highly inefficient, or customized operators [9] that can only be used on specific devices, making application of BEV perception methods costly. Second, the size of \"lifted\" multi-view image features is huge, becoming the memory bottleneck of BEV models. These two issues lead to a heavy burden on BEV methods during both the training and inference phases. As", + "bbox": [ + 496, + 750, + 895, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding author. This research was supported by National Key R&D Program of China (No. 2017YFA0700800) and Beijing Academy of Artificial Intelligence (BAAI).", + "bbox": [ + 75, + 862, + 470, + 900 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "8548", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "a result, the drawbacks of existing view transformers limit the broad application of autonomous driving technology", + "bbox": [ + 76, + 90, + 468, + 119 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this work, we propose a novel VT method to address the above problems. MatrixVT is proposed based on the fact that the VT can be viewed as a feature transportation process. In that case, the BEV feature can be viewed as the MatMul between the \"lifted\" feature and a transporting matrix, namely Feature Transporting Matrix (FTM). We thus generalize the Lift-Splat VT into a simple form and eliminate specialized operators.", + "bbox": [ + 75, + 121, + 467, + 241 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "However, transformation with FTM is a kind of degradation — the mapping between the 3D space and BEV grids is extreme sparse, leading to the huge size of FTM and poor efficiency. Prior works [9, 18] seek customized operators, successfully avoiding such sparsity. In this paper, we argue that there are other solutions to the problem of sparse mapping. First, we propose Prime Extraction. Motivated by an observation that the height (vertical) dimension of images is less informative in autonomous driving (see Sec. 3.2), we compress the image features along this dimension before VT. Second, we adopt matrix decomposition to reduce the sparsity of FTM. The proposed Ring & Ray Decomposition orthogonally decomposes the FTM into two separate matrices, each encoding the distance and direction of the ego-centric polar coordinate. This decomposition also allows us to reformulate our pipeline into a mathematically equivalent but more efficient one (Fig. 1, lower). These two techniques reduce memory footprint and calculation during VT by hundreds of times, enabling MatrixVT to be more efficient than existing methods.", + "bbox": [ + 75, + 242, + 467, + 542 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The proposed MatrixVT inherits the advantages of the Lift-Splat [17] paradigm while being much more memory efficient and fast. Extensive experimental results show that MatrixVT is 2-to-8 times faster than previous methods [9, 6] and saves up to $97\\%$ memory footprint among different settings. Meanwhile, the perception model with MatrixVT achieves $46.6\\%$ mAP and $56.2\\%$ NDS for object detection and $46.2\\%$ mIoU for vehicle segmentation on the nuScenes [2] val set, which is comparable to the state-of-the-art performance [9]. We conclude our main contributions as follows:", + "bbox": [ + 75, + 544, + 467, + 708 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose a new description of multi-camera to BEV transformation — using the Feature Transportation Matrix (FTM), which is a more general representation.", + "- To solve the sparse mapping problem, we propose Prime Extraction and the Ring & Ray Decomposition, boosting VT with FTM by a huge margin.", + "- Extensive experiments demonstrate that MatrixVT yields comparable performance to the state-of-the-art method on the nuScenes object detection and map segmentation tasks while being more efficient and generally applicable." + ], + "bbox": [ + 94, + 717, + 467, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Works", + "text_level": 1, + "bbox": [ + 500, + 89, + 648, + 104 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Visual 3D Perception", + "text_level": 1, + "bbox": [ + 500, + 114, + 697, + 131 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Camera-based perception [28, 27, 6, 10, 11] is the most commonly used method for various scenarios due to its low cost and high accessibility. Comparing with 2D perception (object detection [26], semantic segmentation [22], etc.), 3D perception requires additional prediction of the depth information which is a naturally ill-posed problem [21].", + "bbox": [ + 496, + 138, + 890, + 229 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Existing works either predict the depth information explicitly or implicitly. FCOS3D [28] simply extends the structure of the classic 2D object detector [26], predicting pixel-wise depth explicitly using an extra sub-net. CaDDN [18] proposes treating depth prediction as a classification task rather than a regression task, and projecting image feature into Bird's-Eye-View (BEV) space to achieve unified modeling of detection and depth prediction. BEVDepth [9] proposes a heavy and well-designed subnet for depth prediction, achieving outstanding performance among other 3D object detectors. Meanwhile, methods like PON [20], BirdGAN [24], and EFT [23] use fully learnable networks to implement feature transformation, learning object depth implicitly using segmentation or detection supervision. Among theme, EFT [23] proposes using a learnable matrix for VT, which bears some resemblance, in form, to the Feature Transformation Matrix (FTM) we proposed. However, the matrices we designed for MatrixVT contains clear physical meanings with explicit depth modeling, and there are significant differences in their applicable scenarios and methods of use.", + "bbox": [ + 496, + 229, + 890, + 546 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. Perception in Bird's-Eye-View", + "text_level": 1, + "bbox": [ + 500, + 559, + 767, + 574 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The concept of BEV is firstly proposed for processing LiDAR point cloud [33, 7, 31, 32], and found effective for fusing multi-view image features. The core component of vision-based BEV paradigm is the view-transformation. OFT [21] firstly propose mapping image feature from Perspective View into BEV using camera parameters. This method projects a reference point from a BEV grid to the image plane, and sample corresponding features back to the BEV grid. Following this work, BEVFormer [10] proposes using Attention module to sample features around the reference point. These methods fail to distinguish BEV grids that are projected to the same position on the image plane, thus showing inferior performance than depth-based methods.", + "bbox": [ + 496, + 582, + 890, + 792 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Depth-based methods, represented by LSS [17] and CaDDN [18], predict categorical depth for each pixel, the extracted image feature on a specific pixel is then projected into 3D space by doing per-pixel outer product with corresponding depth. The projected high-dimensional tensor is then \"collapsed\" to a BEV reference plane using convolution [18], Pillar Pooling [17, 6], or Voxel Pooling [9]. Lift-", + "bbox": [ + 496, + 794, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "8549", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Splat based methods [17, 9, 6] show outstanding performance for downstream tasks but introduce two extra problems. Firstly, the intermediate representation of image features is large and in-efficient, making training and application of these methods difficult. Secondly, the Pillar Pooling [17] introduces random memory access, which is slow and device-demanding (extremely slow on general-purpose devices). In this paper, we propose a new depth-based view transformation to overcome these problems while retaining the ability to produce high-quality BEV features.", + "bbox": [ + 75, + 90, + 472, + 243 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. MatrixVT", + "text_level": 1, + "bbox": [ + 76, + 256, + 189, + 272 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The MatrixVT is a simple view transformer based on the depth-based VT paradigm. In Sec. 3.1, we first revisit existing Lift-Splat transformation [17, 9] and introduce the concept of Feature Transporting Matrix (FTM) together with the sparse mapping problem. Then, techniques proposed to solve the problem of sparse mapping i.e., Prime Extraction (Sec. 3.2) and Ring & Ray Decomposition (Sec. 3.3), are introduced. In Sec. 3.4, we designate the novel VT method utilizing the aforementioned techniques as MatrixVT, and elaborate its overall pipeline.", + "bbox": [ + 75, + 281, + 468, + 431 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "For clarity, we use letters of the normal script $(e.g. F)$ for tensors, the Roman script for matrices $(e.g. M)$ , and Bold script $(e.g. v)$ for vectors. Besides, $A \\cdot B$ denotes Matrix Multiplication (MatMul), $A \\odot B$ denotes Hadamard Product, and $a \\otimes b$ denotes outer product.", + "bbox": [ + 75, + 431, + 470, + 508 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Background", + "text_level": 1, + "bbox": [ + 76, + 518, + 209, + 534 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Lift-Splat-like methods exploit the idea of pseudo-LiDAR [29] and LiDAR-based BEV methods [33, 7] for View Transformation. Image features are \"lifted\" to 3D space and processed like point cloud. We define $N_{c}$ as the number of cameras for a specific scene; $N_{d}$ as the number of depth bins; $H_{I}$ and $W_{I}$ to be the height and width of image features; $H_{B}$ and $W_{B}$ to be the height and width of BEV features (i.e., shape of BEV grids); $C$ to be the number of feature channels. Consequently, let multi-view image features to be $F \\in \\mathbb{R}^{N_c \\times H_I \\times W_I \\times C}$ ; categorical depth to be $D \\in \\mathbb{R}^{N_c \\times H_I \\times W_I \\times N_d}$ ; BEV features to be $F_{BEV} \\in \\mathbb{R}^{H_B \\times W_B \\times C}$ (initialized to zeros). The Lift-Splat VT first \"lift\" the $F$ into 3D space by doing per-pixel outer product with $D$ , obtaining the high-dimensional intermediate tensor $F_{inter} \\in \\mathbb{R}^{N_c \\times H_I \\times W_I \\times N_d \\times C}$ .", + "bbox": [ + 75, + 542, + 472, + 770 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nF _ {i n t e r} = \\left\\{F _ {i n t e r} ^ {h, w} \\right\\} _ {H _ {I}, W _ {I}} = \\left\\{\\boldsymbol {F} ^ {h, w} \\cdot \\left(\\boldsymbol {D} ^ {h, w}\\right) ^ {T} \\right\\} _ {H _ {I}, W _ {I}} (1)\n$$\n", + "text_format": "latex", + "bbox": [ + 84, + 779, + 468, + 799 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The intermediate tensor can be treated as $N_{c} \\times H_{I} \\times W_{I} \\times N_{d}$ feature vectors, each vector corresponding to a geometric coordinate. The \"splat\" operation is then adopted using operators like Pillar Pooling [17], during which each feature vector is summed to a BEV grid according to geometric coordinates.", + "bbox": [ + 75, + 809, + 470, + 898 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/c35f78c0a1284a07e5b1b47e5e22fea5f606d0fa6d018ed8705abde2f0b82639.jpg", + "image_caption": [ + "Figure 2. Response strengths along vertical and horizontal dimensions. For autonomous driving, the variance of response on the width dimension is higher than height dimension." + ], + "image_footnote": [], + "bbox": [ + 522, + 97, + 879, + 352 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We find that the \"splat\" operation is a fixed mapping between the intermediate tensor and BEV grids. Therefore, we use a Feature Transporting Matrix $\\mathbf{M}_{\\mathrm{FT}} \\in \\mathbb{R}^{(H_B \\times W_B) \\times (N_c \\times H_I \\times W_I \\times N_d)}$ to describe this mapping. The FTM can be strictly equal to Pillar Pooling in LSS [17] or encodes different sampling rules (i.e., Gaussian sampling). The FTM enables feature transportation with Matrix Multiplication (MatMul):", + "bbox": [ + 498, + 421, + 890, + 542 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {F} _ {\\text {B E V}} = \\mathrm {M} _ {\\mathrm {F T}} \\cdot \\mathrm {F} _ {\\text {i n t e r}} \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 620, + 554, + 890, + 570 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\mathrm{F}_{\\mathrm{inter}}\\in \\mathbb{R}^{(N_c\\times H_I\\times W_I\\times N_d)\\times C}$ is the \"lifted\" feature $F_{inter}$ in matrix format, $\\mathrm{F_{BEV}}\\in \\mathbb{R}^{(H_B\\times W_B)\\times C}$ is the BEV feature $F_{BEV}$ in matrix format.", + "bbox": [ + 498, + 579, + 890, + 626 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Replacing the \"splat\" operation with FTM eliminates the need for customized operators. However, the sparse mapping between the 3D space and BEV grids can lead to a massive and highly sparse FTM, which harms the efficiency of matrix-based VT. To address the sparse mapping problem without customized operators, we propose two techniques to reduce the sparsity of FTM and speed up the transformation.", + "bbox": [ + 496, + 627, + 890, + 746 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Prime Extraction for Autonomous Driving", + "text_level": 1, + "bbox": [ + 500, + 756, + 861, + 772 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The high-dimensional intermediate tensor is the primary cause of the sparse mapping and the low efficiency of Lift-Splat-like VT. An intuitive way to reduce sparsity is reducing the size of $F_{inter}$ . In the context of autonomous driving, a notable observation can lead to feature compression. As can be seen in Fig. 2, the height dimension of camera images contains less informative data. The height dimension is filled with redundant and background features, making it", + "bbox": [ + 496, + 779, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "8550", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/97bfd8c3e8fb7a389411074bad6122cdc7fea34b1433ce6a165d97782774cf53.jpg", + "image_caption": [ + "Figure 3. The Prime Extraction module. The categorical depth is reduced guided by Prime Depth Attention, while the image feature is reduced by Prime Feature Extractor (PFE), which consists of MaxPooling and convolutions for refinement." + ], + "image_footnote": [], + "bbox": [ + 86, + 90, + 450, + 368 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "ideal for feature compression. Therefore, we propose Prime Extraction, which is a compression technique that can be used in autonomous driving and other scenarios with information redundancy of this nature.", + "bbox": [ + 75, + 455, + 468, + 516 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "As shown in Fig. 3, the Prime Extraction module predicts Prime Depth Attention for each direction (a column of the tensor) guided by the image feature. It generates the Prime Depth as a weighted sum of categorical depth distributions. Meanwhile, the Prime Feature is obtained by the Prime Feature Extractor (PFE), which consists of position embedding, column-wise max-pooling, and convolutions for refinement. By applying Prime Extraction to matrix-based VT, we successfully reduce the FTM to $\\mathbf{M}_{\\mathrm{FT}}^{\\prime} \\in \\mathbb{R}^{(H_B \\times W_B) \\times (N_c \\times W_I \\times N_d)}$ , which is $H_{I}$ times smaller than the raw matrix. The pipeline of generating the BEV feature using the Prime Feature and the Prime Depth is demonstrated in Fig. 4 (yellow box).", + "bbox": [ + 75, + 518, + 468, + 715 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The prime extraction is motivated by an observation: The image feature's height dimension has a lower response variance than the width dimension. This observation indicates that this dimension contains less information than the width dimension. We thus propose to compress image features on the height dimension. Previous works have also exploited reducing the height dimension of image features [20, 1], but we firstly propose compressing both image features and corresponding depth to boost VT.", + "bbox": [ + 75, + 717, + 468, + 853 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In Sec. 4.4, we will show that the extracted Prime Feature and Prime Depth effectively retain valuable information from the raw feature and produce BEV features of the", + "bbox": [ + 75, + 854, + 470, + 900 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "same high quality as the raw feature. Moreover, the Prime Extraction technique can be individually adapted to existing Lift-Splat-like VTs to enhance their efficiency at almost no performance cost.", + "bbox": [ + 496, + 90, + 892, + 151 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. \"Ring and Ray\" Decomposition", + "text_level": 1, + "bbox": [ + 498, + 161, + 779, + 176 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The sparsity of FTM can be further reduced by matrix decomposition. To this end, we propose the \"Ring & Ray\" Decomposition. Without loss of generality, we can set the $N_{c}$ to 1 and view $\\mathbf{M}_{\\mathrm{FT}}^{\\prime}$ as a tensor $M_{FT}^{\\prime}$ . In that case, the shape of $M_{FT}^{\\prime}$ would be $H_{B} \\times W_{B} \\times W_{I} \\times N_{d}$ . We note that its dimension of size $W_{I}$ can be viewed as the direction in a polar coordinate, since each column of the image feature represents information of a specific direction. Likewise, the dimension of size $N_{d}$ can be viewed as the distance in the polar coordinate. In other words, the image feature required for a specific BEV grid can be located by direction and distance. We thus propose to orthogonally decompose the $M_{FT}^{\\prime}$ into two separate matrices, each encoding the directional or distance information. Specifically, we use a Ring Matrix $\\mathbf{M}_{\\mathrm{Ring}} \\in \\mathbb{R}^{N_d \\times (H_B \\times W_B)}$ to encode distance information and a Ray Matrix $\\mathbf{M}_{\\mathrm{Ray}} \\in \\mathbb{R}^{W_I \\times (H_B \\times W_B)}$ to encode directional information (see Appendix 1.1 for pseudo code). The Ring & Ray Decomposition effectively reduces the size of static parameters. The number of predefined parameters (size of FTM) is reduced from $W_{I} \\times N_{d} \\times H_{B} \\times W_{B}$ to $(W_{I} + N_{d}) \\times H_{B} \\times W_{B}$ , which is typically 30 to 50 times less1.", + "bbox": [ + 496, + 184, + 892, + 517 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Then we show how to use these two matrices for VT. Given the Prime Feature and Prime Depth, we first do the per-pixel outer product of them as in Lift-Splat to obtain the \"lifted feature\" $F_{inter} \\in \\mathbb{R}^{W_I \\times N_d \\times C}$ .", + "bbox": [ + 496, + 517, + 890, + 578 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nF _ {i n t e r} = \\left\\{F _ {i n t e r} ^ {w} \\right\\} _ {W _ {I}} = \\left\\{\\boldsymbol {F} ^ {\\boldsymbol {w}} \\otimes \\left(\\boldsymbol {D} ^ {\\boldsymbol {w}}\\right) ^ {T} \\right\\} _ {W _ {I}} \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 544, + 589, + 890, + 608 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Then, as illustrated in Fig. 4, instead of using $\\mathrm{M}_{\\mathrm{FT}}'$ to directly transform it into a BEV feature (yellow box), we transpose $F_{inter}$ , view it as a matrix $\\mathrm{F}_{\\mathrm{inter}} \\in \\mathbb{R}^{N_d \\times (W_I \\times C)}$ , and do MatMul between the Ring Matrix and $\\mathrm{F}_{\\mathrm{inter}}$ to obtain an intermediate feature. The intermediate feature is then masked by doing a Hadamard Product with the Ray Matrix, summed on the dimension of $W_I$ to obtain the BEV feature. (Fig. 4, blue box, summation omitted).", + "bbox": [ + 496, + 618, + 890, + 739 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {F} _ {\\text {i n t e r}} ^ {*} = \\mathrm {M} _ {\\text {R a y}} \\odot (\\mathrm {M} _ {\\text {R i n g}} \\cdot \\mathrm {F} _ {\\text {i n t e r}}) \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 580, + 752, + 890, + 768 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nF _ {B E V} = \\sum_ {w} F _ {\\text {i n t e r}} ^ {* w} \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 627, + 772, + 890, + 801 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $F_{inter}^{*}\\in \\mathbb{R}^{W_I\\times C\\times H_B\\times W_B}$ is $\\mathrm{F}_{\\mathrm{inter}}^{*}$ in tensor form.", + "bbox": [ + 496, + 814, + 880, + 832 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "However, this decomposition do not reduce the FLOPs during VT and introduces the Intermediate Feature in Fig. 4 (blue) whose size if huge and depends on feature channel", + "bbox": [ + 496, + 832, + 890, + 876 + ], + "page_idx": 3 + }, + { + "type": "page_footnote", + "text": "Under feature width 44 and 88, with 112 depth bins.", + "bbox": [ + 514, + 886, + 800, + 898 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "8551", + "bbox": [ + 480, + 944, + 513, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/5649bb5366d44480f42c3ea588f88dd7b376088d50546afcc108adc67a7bacb3.jpg", + "image_caption": [ + "Pipelines of View Transformation Using Matrices", + "Figure 4. View Transformation using matrices. We first extract features from the image and predict categorical depth for each pixel. The obtained feature and depth are sent to the Prime Extraction module for compression. With the compressed Prime Feature and the Prime Depth, we \"lift\" the 1D Prime Feature into 2D space using Prime Depth. The \"lifted feature\" is then transformed into the BEV feature by MatMul with FTM or the decomposed Ring & Ray matrices." + ], + "image_footnote": [], + "bbox": [ + 86, + 111, + 890, + 334 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "$C$ . To reduce the calculation and memory footprint during VT, we combine Eq. 3 to Eq. 5 and rewrite them in a mathematically equivalent form (see Appendix 1.2 for proof):", + "bbox": [ + 76, + 417, + 468, + 464 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {F} _ {\\mathrm {B E V}} = \\mathrm {F} \\cdot \\left(\\mathrm {M} _ {\\text {R a y}} \\odot \\left(\\mathrm {M} _ {\\text {R i n g}} \\cdot \\mathrm {D}\\right)\\right) \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 151, + 473, + 468, + 491 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "With this reformulation, we reduce the calculation during VT from $2 \\times W_{I} \\times C \\times N_{d} \\times H_{B} \\times W_{B}$ FLOPs to $2(C + N_{d} + 1) \\times W_{I} \\times H_{B} \\times W_{B}$ FLOPs; the memory footprint is also reduced from $W_{I} \\times N_{d} \\times H_{B} \\times W_{B}$ to $(W_{I} + N_{d}) \\times H_{B} \\times W_{B}$ .", + "bbox": [ + 76, + 500, + 468, + 575 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.4. Overall Pipeline", + "text_level": 1, + "bbox": [ + 76, + 584, + 238, + 599 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "With above techniques, we reduce the calculation and memory footprint using FTM by hundreds of times, making VT with FTM not only feasible but also efficient. Given the multi-view images for a specific scene, we conclude the overall pipeline of MatrixVT as follows:", + "bbox": [ + 75, + 607, + 468, + 681 + ], + "page_idx": 4 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1. We first use an image backbone to extract image features from each image.", + "2. Then, a depth predictor is adopted to predict categorical depth distribution for each feature pixel to obtain the depth prediction.", + "3. After that, we send each image feature and corresponding depth to the Prime Extraction module, obtaining the Prime Feature and the Prime Depth, which is the compressed feature and depth.", + "4. Finally, with the Prime Feature, Prime Depth, and the pre-defined Ring & Ray Matrices, we use Eq. 6 (see also Fig. 1, lower) to obtain the BEV feature." + ], + "bbox": [ + 88, + 691, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 500, + 416, + 632, + 434 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In this section, we compare the performance, latency, and memory footprint of MatrixVT and other existing VT methods on the nuScenes benchmark [2].", + "bbox": [ + 498, + 441, + 890, + 488 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Implementation Details", + "text_level": 1, + "bbox": [ + 498, + 500, + 718, + 515 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We conduct our experiments based on BEVDepth [9], the current state-of-the-art detector on the nuScenes benchmark. In order to conduct a fair comparison of performance and efficiency, we re-implement BEVDepth according to their paper. Unless otherwise specified, we use ResNet50 [3] and VoVNet2-99 [8] pre-trained on DD3D [16] as the image backbone and SECOND FPN [31] as the image neck and BEV neck. The input image adopts pre-processing and data augmentations same as in [9]. We use BEV feature size $128 \\times 128$ for low input resolution and $256 \\times 256$ for high resolution on detection. Segmentation experiments use $200 \\times 200$ BEV resolution as in LSS [17]. We use the DepthNet [9] to predict categorical depth from $2\\mathrm{m}$ to $58\\mathrm{m}$ in nuScenes, with uniform 112 division. During training, CBGS [34] and model EMA are adopted. Models are trained to converge since MatrixVT converges a little slower than other methods, but no more than 30 epochs.", + "bbox": [ + 496, + 522, + 890, + 780 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Comparison of Performances", + "text_level": 1, + "bbox": [ + 498, + 791, + 759, + 806 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2.1 Object Detection", + "text_level": 1, + "bbox": [ + 500, + 815, + 671, + 830 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We conduct experiments under several settings to evaluate the performance of MatrixVT in Tab. 1 and Tab. 2. On the nuScenes benchmark, we first adopt the ResNet family as the backbone without applying multi-frame fusion.", + "bbox": [ + 496, + 839, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "8552", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/09df9ee9fe0938dad35376ee5e2e4d0119f41b017d0cab9fde125e66fdeefc99.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodBackboneResolutionMFmAP↑mATE↓mASE↓mAOE↓mAVE↓mAAE↓NDS↑
BEVDet [6]Res-50256 × 704×0.2860.7240.2780.5900.8730.2470.372
PETR [11]Res-50384 × 1056×0.3130.7680.2780.5640.9230.2250.381
BEVDepth [9]Res-50256 × 704×0.3370.6460.2710.5740.8380.2200.414
MatrixVTRes-50256 × 704×0.3360.6530.2710.4730.9030.2310.415
BEVDet [6]Res-101384 × 1056×0.3300.7020.2720.5340.9320.2510.396
FCOS3D [28]Res-101900 × 1600×0.3430.7250.2630.4221.2920.1530.415
PETR [11]Res-101512 × 1408×0.3570.7100.2700.4900.8850.2240.421
BEVFormer [10]R101-DCN900 × 1600×0.3750.7250.2720.3910.8020.2000.448
MatrixVTRes-101512 × 1408×0.3960.5770.2610.3970.8700.2070.467
BEVFormer [10]R101-DCN900 × 1600✓0.4160.6730.2740.3720.3940.1980.517
BEVDet4D [5]Swin-B640 × 1600✓0.4210.5790.2580.3290.3010.1910.545
BEVDepth [9]V2-99512 × 1408✓0.4640.5280.2540.3500.3540.1980.564
MatrixVTV2-99512 × 1408✓0.4660.5350.2600.3800.3420.1980.562
", + "bbox": [ + 81, + 89, + 893, + 318 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/1a605d32f9e5723de0d42c911e19655279ccb4f6be11faf14a00c817df49d34e.jpg", + "table_caption": [ + "Table 1. Experimental results of object detection on the nuScenes val set. The \"MF\" indicates multi-frame fusion." + ], + "table_footnote": [], + "table_body": "
MethodBackbonemAP↑mAPH↑mAPL↑
BEVDepth [9]Res-500.2900.2080.253
MatrixVTRes-500.3040.2150.259
", + "bbox": [ + 81, + 366, + 470, + 422 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "MatrixVT achieves $33.6\\%$ and $49.7\\%$ mAP with ResNet-50 and ResNet-101, which is comparable to the BEVDepth [9] and surpasses other methods by a large margin. We then test the upper bound of MatrixVT by replacing the backbone with V2-99 [8] pre-trained on external data and applying multi-frame fusion. Under this setting, MatrixVT achieves $46.6\\%$ mAP and $56.2\\%$ NDS, which is also comparable to the BEVDepth. Further, we validate if MatrixVT can be generalize to other benchmark. We conduct experiments on the Waymo benchmark [25], results show that MatrixVT still showing comparable or even better performance under this setting.", + "bbox": [ + 75, + 474, + 468, + 657 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2.2 Map Segmentation", + "text_level": 1, + "bbox": [ + 76, + 679, + 263, + 695 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We also conduct experiments on map segmentation tasks to validate the quality of the BEV feature generated by MatrixVT. To achieve this, we simply put a U-Net-like [22] segmentation head on the BEV feature. For fair comparison, we put the same head on the BEV feature of BEVDepth for experiments, and results are reported as \"BEVDepth-Seg\" in Tab. 3. It is worth noting that previous works achieve the best segmentation performance under different settings (different resolution, head structure, etc.); thus, we report the highest performance of each method. As can be seen from Tab. 3, the map segmentation performance of MatrixVT surpasses most existing methods on all three subtasks and is comparable to our baseline, BEVDepth.", + "bbox": [ + 75, + 704, + 470, + 902 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/c6f3c0aa70e03cd73750b35afe779319f95922a034f34707be6fea1430436157.jpg", + "table_caption": [ + "Table 2. Performance of object detection on Waymo val set." + ], + "table_footnote": [], + "table_body": "
MethodIoU-Drive↑IoU-Lane↑IoU-Vehicle↑
LSS [17]0.7290.2000.321
FIERY [4]--0.382
M2BEV [30]0.7590.380-
BEVFormer [10]0.7750.2390.467
BEVDepth-Seg0.8270.4640.450
MatrixVT0.8350.4480.462
", + "bbox": [ + 504, + 366, + 890, + 479 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 3. Experimental results of BEV segmentation on the nuScenes val set. We implement map segmentation on the BEVDepth by placing a segmentation head on the BEV feature.", + "bbox": [ + 500, + 479, + 890, + 522 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Efficient Transformation", + "text_level": 1, + "bbox": [ + 500, + 559, + 725, + 574 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We compare the efficiency of View Transformation in two dimensions: Speed and Memory Consumption. Note that we measure the latency and memory footprint (using fp32) of view transformers since these metrics are affected by backbone and head design. We take the CPU as a representative general-purpose device where customized operators are unavailable. For a fair comparison, we measure and compare the other two Lift-Splat-like view transformers. The LS-BEVDet is the accelerated transformation used in BEVDet (with default parameters); the LS-BEVDepth uses the CUDA [14] operator proposed in BEVDepth [9] that is not available on CPU and other platforms. To demonstrate the characteristics of different methods, we define six transformation settings, namely S1~S6, varies in image feature size, BEV feature size, and feature channels that are closely related to model performance.", + "bbox": [ + 496, + 582, + 890, + 824 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "As can be seen in Fig. 5, the proposed MatrixVT boost the transformation significantly on the CPU, being 4 to 8 times faster than the LS-BEVDet[6]. On the CUDA platform [14], where customized operators enable faster transformation, MatrixVT still shows a much faster speed than", + "bbox": [ + 496, + 824, + 893, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "8553", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/167e5a7a753d5e47c4cf4bd2389f2e2cb15c5ca2c4e43949673d39d555a9f20e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 294, + 89, + 676, + 112 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/ded93cdc4bf4aef54294406476dfc3d52bbbc10d04ae3ba608d09bb52dce2614.jpg", + "image_caption": [ + "Figure 5. Latency (left, middle) and the number of intermediate parameters (right) of MatrixVT and two implementations of Lift-Splat, the S1~S6 denote transformation settings represented by image feature size $(C\\times H_I\\times W_I)$ to BEV feature size $(C\\times H_B\\times W_B)$ . Note that the LS-BEVDet raises Out Of Memory error under S5 and S6 on CUDA. The LS-BEVDepth is not available without the CUDA platform." + ], + "image_footnote": [], + "bbox": [ + 86, + 114, + 356, + 268 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/eb4cee2494ada4bad1b00836d9134a3aea896492a8e3838bd96043a5d826731e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 357, + 114, + 620, + 268 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/d546a5d926b953d7be6a60ab7721c0388dd5389fddd4a921c85a5a7925c74cb2.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 622, + 114, + 883, + 268 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "the LS-BEVDepth under most settings. Besides, we calculate the number of intermediate variables during VT as an indicator of extra memory footprint. For MatrixVT, these variables include the Ring Matrix, Ray Matrix, and intermediate matrix; for Lift-Splat, intermediate variables include the intermediate tensor and the predefined BEV grids. As illustrated in Fig. 5 (right), MatrixVT consumes 2 to 15 times less memory than LS-BEVDepth and 40 to 80 times less memory than LS-BEVDet.", + "bbox": [ + 75, + 343, + 468, + 479 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In Tab. 4, we adopt our proposed methods onto the BEVDepth step-by-step and evaluate improvements in memory footprint and latency. It can be seen that Prime Extraction effectively reduced memory footprint and latency by a large margin. For the low-resolution setting (Res-50 & 256), the Ring & Ray FTM further reduces the resource consumption. For the high-resolution setting (V2-99 & $512 \\times 1408$ ), the application of Ring & Ray FTM enabled VT without custom operators at cost of extra computation.", + "bbox": [ + 75, + 479, + 468, + 614 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4. Effectiveness", + "text_level": 1, + "bbox": [ + 76, + 625, + 215, + 638 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In this section, we validate the effectiveness of the proposed methods by performance comparison and visualization.", + "bbox": [ + 75, + 647, + 468, + 691 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4.1 Effects on Performance", + "text_level": 1, + "bbox": [ + 76, + 710, + 294, + 724 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "As mentioned in Sec. 3.2, we argue that the features and corresponding depths can be compressed with little or no information loss. We thus individually adopt the Prime Extraction and the Ring & Ray FTM onto the BEVDepth [9] to verify their effectiveness. To adopt Prime Extraction individually, we compress image features and the depths before the common Lift-Splat. As shown in Tab. 4, the BEVDepth with our improvements achieves $41.5\\%$ NDS with Res-50 and $56.2\\%$ NDS with VovNetv2-99 [8], which is comparable to the baseline. Thus, we argue that Prime Extraction effectively retained key information from raw features, and", + "bbox": [ + 75, + 734, + 470, + 900 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/201b567a5a280ebcb72498bb571dc4e075170d7ca0822aaf5834015eeb98cdef.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
BackbonePERRNDSMem.Lat. (ms)
Res-500.416528M1.79
Res-50✓0.41694M1.42
Res-50✓✓0.41583M1.33
V2-990.5642.14G8.85
V2-99✓0.563405M2.04
V2-99✓✓0.562498M3.19
", + "bbox": [ + 514, + 340, + 879, + 468 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 4. Effects of using Prime Extraction (PE) and Ring & Ray FTM (RR) on BEVDepth. The memory consumption and latency reported is the memory footprint and time duration on PyTorch during View Transformation (VT).", + "bbox": [ + 498, + 468, + 890, + 522 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "the application of Ring & Ray FTM would not harm the final performance.", + "bbox": [ + 498, + 561, + 890, + 592 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4.2 Prime Information in Object Detection", + "text_level": 1, + "bbox": [ + 500, + 614, + 823, + 630 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We then delve into the mechanism of Prime Extraction by visualization. Fig. 6 shows the inputs and outputs of the Prime Extraction module. It can be seen that the Prime Extraction module trained on different tasks focusing on different information. The Prime Depth Attention in object detection focuses on foreground objects. Thus the Prime Depth retained the depth of objects while ignoring the depth of the background. Also, it can be seen from the yellow car in the second column, which is obscured by three pedestrians. Prime Extraction effectively distinguishes these objects at different depths.", + "bbox": [ + 496, + 640, + 890, + 806 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4.3 Prime Information in Map Segmentation", + "text_level": 1, + "bbox": [ + 500, + 830, + 839, + 845 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "For the map segmentation task, we take lane segmentation as an example — the Prime Extraction module focus on lane and road that is closely related to this task. However, since", + "bbox": [ + 498, + 854, + 892, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "8554", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/9b94ca56bbfb5a908de8c332f591a76603595681acf1e0f907267d2c73181453.jpg", + "image_caption": [ + "Figure 6. Depth Prediction, Prime Depth Attention, and Prime Depth for object detection and lane segmentation task. The categorical depth prediction is illustrated using distances with largest probability, while the Prime Depth is illustrated by raw probability values." + ], + "image_footnote": [], + "bbox": [ + 89, + 93, + 893, + 378 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "the area of the target category is a wide range covering several depth bins, the distribution of Prime Depth is uniform in the target area (see Fig. 6, 3rd and 4th columns). The observation indicates that Prime Extraction generates a new form of depth distribution that fits the map segmentation task. With the Prime Depth that is rather uniform, the same feature can be projected to multiple depth bins since they are occupied by the same category.", + "bbox": [ + 75, + 433, + 472, + 555 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.5. Extraction of Prime Feature", + "text_level": 1, + "bbox": [ + 76, + 569, + 330, + 584 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In the Prime Feature Extractor, we propose using max pooling followed by several 1D convolutions to reduce and refine the image feature. Before reduction, the coordinate of each pixel is embedded into the feature as position embedding. We conduct experiments to validate the contribution of each design.", + "bbox": [ + 75, + 595, + 468, + 685 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "A possible alternative of the max pooling is the CollapseConv as in [18] and [20], which merges the height dimension into the channel dimension and reduces the merged channel by linear projection. However, the design of CollapseConv brings some disadvantages. For example, the merged dimension is of size $C \\times H$ , which is high and requires extra memory transportation. To address these problems, we propose using max pooling to reduce the image feature in Prime Extraction. Tab. 5 shows that reduction using max pooling achieves even better performance than CollapseConv while eliminating these shortcomings.", + "bbox": [ + 75, + 686, + 468, + 853 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We also conduct experiments to show the effectiveness of the refine sub-net after reducing in Tab. 5. The results indicate that the refine sub-net plays a vital role in adapting", + "bbox": [ + 75, + 854, + 470, + 901 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/307ea17f8b5e6c885169a27fe2deca8d0a87fd3dee4f33cf05a5ef7b45c98a74.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ReductionRefinePos. Emb.mAPNDS
Max Pooling0.3280.393
Max Pooling✓0.3320.414
Max Pooling✓✓0.3360.415
CollapseConv✓✓0.3340.404
", + "bbox": [ + 506, + 431, + 885, + 521 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 5. Performance of MatrixVT with different feature reduction methods. The \"Refine\" indicates the refine convs, the \"Pos.Emb.\" indicates using front-view position embedding.", + "bbox": [ + 500, + 521, + 890, + 561 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "the reduced feature to BEV space, without which a performance drop of $0.9\\%$ mAP will occur. Finally, the experimental results in Tab. 5 have shown that the position embedding brings an improvement of $0.4\\%$ mAP, which is also preferable.", + "bbox": [ + 498, + 599, + 890, + 676 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 688, + 617, + 704 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "This paper proposes a new paradigm of View Transformation (VT) from multi-camera to Bird's-Eye-View. The proposed method, MatrixVT, generalizes VT into a feature transportation matrix. We then propose Prime Extraction, which eliminates the redundancy during transformation, and the Ring & Ray Decomposition, which simplifies and boost the transformation. While being faster and more efficient on both specialized devices like GPU and general-purpose devices like CPU, our extensive experiments on the nuScenes benchmark indicate that the MatrixVT offers comparable performance to the state-of-the-art method.", + "bbox": [ + 496, + 714, + 890, + 880 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "8555", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 174, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Xuyang Bai, Zeyu Hu, Xinge Zhu, Qingqiu Huang, Yilun Chen, Hongbo Fu, and Chiew-Lan Tai. Transfusion: Robust lidar-camera fusion for 3d object detection with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1090-1099, 2022. 1, 4", + "[2] Holger Caesar, Varun Bankiti, Alex H. Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2020, Seattle, WA, USA, June 13-19, 2020, pages 11618-11628. IEEE, 2020. 2, 5", + "[3] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In 2016 IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2016, Las Vegas, NV, USA, June 27-30, 2016, pages 770-778. IEEE Computer Society, 2016. 5", + "[4] Anthony Hu, Zak Murez, Nikhil Mohan, Sofia Dudas, Jeffrey Hawke, Vijay Badrinarayanan, Roberto Cipolla, and Alex Kendall. Fiery: Future instance prediction in bird's-eye view from surround monocular cameras. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 15273-15282, 2021. 6", + "[5] Junjie Huang and Guan Huang. Bevdet4d: Exploit temporal cues in multi-camera 3d object detection. ArXiv preprint, abs/2203.17054, 2022. 1, 6", + "[6] Junjie Huang, Guan Huang, Zheng Zhu, and Dalong Du. Bevdet: High-performance multi-camera 3d object detection in bird-eye-view. ArXiv preprint, abs/2112.11790, 2021. 1, 2, 3, 6", + "[7] Alex H. Lang, Sourabh Vora, Holger Caesar, Lubing Zhou, Jiong Yang, and Oscar Beijbom. Pointpillars: Fast encoders for object detection from point clouds. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 12697-12705. Computer Vision Foundation / IEEE, 2019. 2, 3", + "[8] Youngwan Lee and Jongyoul Park. Centermask: Real-time anchor-free instance segmentation. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2020, Seattle, WA, USA, June 13-19, 2020, pages 13903-13912. IEEE, 2020. 5, 6, 7", + "[9] Yinhao Li, Zheng Ge, Guanyi Yu, Jinrong Yang, Zengran Wang, Yukang Shi, Jianjian Sun, and Zeming Li. Bevdepth: Acquisition of reliable depth for multi-view 3d object detection. ArXiv preprint, abs/2206.10092, 2022. 1, 2, 3, 5, 6, 7", + "[10] Zhiqi Li, Wenhai Wang, Hongyang Li, Enze Xie, Chonghao Sima, Tong Lu, Qiao Yu, and Jifeng Dai. BEV-Former: Learning Bird's-Eye-View Representation from Multi-Camera Images via Spatiotemporal Transformers. ArXiv preprint, abs/2203.17270, 2022. 1, 2, 6", + "[11] Yingfei Liu, Tiancai Wang, Xiangyu Zhang, and Jian Sun. Petr: Position embedding transformation for multi-view 3d object detection. ArXiv preprint, abs/2203.05625, 2022. 2, 6" + ], + "bbox": [ + 78, + 114, + 470, + 901 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[12] Zhijian Liu, Haotian Tang, Alexander Amini, Xinyu Yang, Huizi Mao, Daniela Rus, and Song Han. Bevfusion: Multitask multi-sensor fusion with unified bird's-eye view representation. arXiv preprint arXiv:2205.13542, 2022. 1", + "[13] Hanspeter A Mallot, Heinrich H Bülthoff, JJ Little, and Stefan Bohrer. Inverse perspective mapping simplifies optical flow computation and obstacle detection. Biological cybernetics, 64(3):177-185, 1991. 1", + "[14] NVIDIA, Péter Vingelmann, and Frank H.P. Fitzek. Cuda, release: 10.2.89, 2020. 6", + "[15] Bowen Pan, Jiankai Sun, Ho Yin Tiga Leung, Alex Andonian, and Bolei Zhou. Cross-view semantic segmentation for sensing surroundings. IEEE Robotics and Automation Letters, 5(3):4867-4873, 2020. 1", + "[16] Dennis Park, Rares Ambrus, Vitor Guizilini, Jie Li, and Adrien Gaidon. Is pseudo-lidar needed for monocular 3d object detection? In IEEE/CVF International Conference on Computer Vision (ICCV), 2021. 5", + "[17] Jonah Philion and Sanja Fidler. Lift, splat, shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3d. In European Conference on Computer Vision, pages 194-210. Springer, 2020. 1, 2, 3, 5, 6", + "[18] Cody Reading, Ali Harakeh, Julia Chae, and Steven L. Waslander. Categorical depth distribution network for monocular 3d object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 8555-8564, 2021. 1, 2, 8", + "[19] Lennart Reiher, Bastian Lampe, and Lutz Eckstein. A sim2real deep learning approach for the transformation of images from multiple vehicle-mounted cameras to a semantically segmented image in bird's eye view. In 2020 IEEE 23rd International Conference on Intelligent Transportation Systems (ITSC), pages 1-7. IEEE, 2020. 1", + "[20] Thomas Roddick and Roberto Cipolla. Predicting semantic map representations from images using pyramid occupancy networks. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2020, Seattle, WA, USA, June 13-19, 2020, pages 11135-11144. IEEE, 2020. 1, 2, 4, 8", + "[21] Thomas Roddick, Alex Kendall, and Roberto Cipolla. Orthographic feature transform for monocular 3d object detection. In 30th British Machine Vision Conference 2019, BMVC 2019, Cardiff, UK, September 9-12, 2019, page 285. BMVA Press, 2019. 1, 2", + "[22] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image computing and computer-assisted intervention, pages 234-241. Springer, 2015. 2, 6", + "[23] Daeyun Shin, Zhile Ren, Erik B Sudderth, and Charless C Fowlkes. 3d scene reconstruction with multi-layer depth and epipolar transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2172-2182, 2019. 2", + "[24] Siddharth Srivastava, Frederic Jurie, and Gaurav Sharma. Learning 2d to 3d lifting for object detection in 3d for autonomous vehicles. In 2019 IEEE/RSJ International Confer-" + ], + "bbox": [ + 501, + 92, + 890, + 901 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "8556", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "ence on Intelligent Robots and Systems (IROS), pages 4504-4511. IEEE, 2019. 1, 2", + "[25] Pei Sun, Henrik Kretzschmar, Xerxes Dotiwalla, Aurelien Chouard, Vijaysai Patnaik, Paul Tsui, James Guo, Yin Zhou, Yuning Chai, Benjamin Caine, Vijay Vasudevan, Wei Han, Jiquan Ngiam, Hang Zhao, Aleksei Timofeev, Scott Ettinger, Maxim Krivokon, Amy Gao, Aditya Joshi, Yu Zhang, Jonathon Shlens, Zhifeng Chen, and Dragomir Anguelov. Scalability in perception for autonomous driving: Waymo open dataset. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), June 2020. 6", + "[26] Zhi Tian, Chunhua Shen, Hao Chen, and Tong He. FCOS: fully convolutional one-stage object detection. In 2019 IEEE/CVF International Conference on Computer Vision, ICCV 2019, Seoul, Korea (South), October 27 - November 2, 2019, pages 9626-9635. IEEE, 2019. 2", + "[27] Tai Wang, ZHU Xinge, Jiangmiao Pang, and Dahua Lin. Probabilistic and geometric depth: Detecting objects in perspective. In Conference on Robot Learning, pages 1475-1485. PMLR, 2022. 2", + "[28] Tai Wang, Xinge Zhu, Jiangmiao Pang, and Dahua Lin. Fcos3d: Fully convolutional one-stage monocular 3d object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 913-922, 2021. 2, 6", + "[29] Yan Wang, Wei-Lun Chao, Divyansh Garg, Bharath Hariharan, Mark E. Campbell, and Kilian Q. Weinberger. Pseudolidar from visual depth estimation: Bridging the gap in 3d object detection for autonomous driving. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 8445-8453. Computer Vision Foundation / IEEE, 2019. 3", + "[30] Enze Xie, Zhiding Yu, Daquan Zhou, Jonah Philion, Anima Anandkumar, Sanja Fidler, Ping Luo, and Jose M Alvarez. M^2bev: Multi-camera joint 3d detection and segmentation with unified birds-eye view representation. ArXiv preprint, abs/2204.05088, 2022. 1, 6", + "[31] Yan Yan, Yuxing Mao, and Bo Li. Second: Sparsely embedded convolutional detection. Sensors, 18(10):3337, 2018. 2, 5", + "[32] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Center-based 3d object detection and tracking. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 11784-11793, 2021. 2", + "[33] Yin Zhou and Oncel Tuzel. Voxelnet: End-to-end learning for point cloud based 3d object detection. In 2018 IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2018, Salt Lake City, UT, USA, June 18-22, 2018, pages 4490-4499. IEEE Computer Society, 2018. 2, 3", + "[34] Benjin Zhu, Zhengkai Jiang, Xiangxin Zhou, Zeming Li, and Gang Yu. Class-balanced grouping and sampling for point cloud 3d object detection. ArXiv preprint, abs/1908.09492, 2019. 5" + ], + "bbox": [ + 78, + 90, + 468, + 835 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "8557", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/3d8f338d-7ad3-414d-a017-25b8e25151fd_model.json b/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/3d8f338d-7ad3-414d-a017-25b8e25151fd_model.json new file mode 100644 index 0000000000000000000000000000000000000000..22831d52d9cdb0b58de13e52dcdac7414875bfe0 --- /dev/null +++ b/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/3d8f338d-7ad3-414d-a017-25b8e25151fd_model.json @@ -0,0 +1,1947 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.096, + 0.131, + 0.877, + 0.155 + ], + "angle": 0, + "content": "MatrixVT: Efficient Multi-Camera to BEV Transformation for 3D Perception" + }, + { + "type": "text", + "bbox": [ + 0.271, + 0.181, + 0.705, + 0.218 + ], + "angle": 0, + "content": "Hongyu Zhou, Zheng Ge, Zeming Li, Xiangyu Zhang* MEGVII Technology" + }, + { + "type": "text", + "bbox": [ + 0.238, + 0.22, + 0.733, + 0.234 + ], + "angle": 0, + "content": "{zhouhongyu, gezheng, lizeming, zhangxiangyu}@megvii.com" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.269, + 0.314, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.301, + 0.474, + 0.604 + ], + "angle": 0, + "content": "This paper proposes an efficient multi-camera to Bird's-Eye-View (BEV) view transformation method for 3D perception, dubbed MatrixVT. Existing view transformers either suffer from poor efficiency or rely on device-specific operators, hindering the broad application of BEV models. In contrast, our method generates BEV features efficiently with only convolutions and matrix multiplications (MatMul). Specifically, we propose describing the BEV feature as the MatMul of image feature and a sparse Feature Transporting Matrix (FTM). A Prime Extraction module is then introduced to compress the dimension of image features and reduce FTM's sparsity. Moreover, we propose the Ring & Ray Decomposition to replace the FTM with two matrices and reformulate our pipeline to reduce calculation further. Compared to existing methods, MatrixVT enjoys a faster speed and less memory footprint while remaining deploy-friendly. Extensive experiments on nuScenes and Waymo benchmarks demonstrate that our method is highly efficient but obtains results on par with the SOTA method in object detection and map segmentation tasks." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.632, + 0.21, + 0.648 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.657, + 0.47, + 0.779 + ], + "angle": 0, + "content": "Vision-centric 3D perception in Bird's-Eye-View (BEV) [17, 20, 24] has recently drawn extensive attention. Apart from their outstanding performance, the compact and unified feature representation in BEV facilitates straight-forward feature fusions [1, 5, 12, 10], and enables various downstream tasks (e.g. object detection [6, 9, 10], map segmentation [17, 30], motion planning, etc.) to be applied thereon easily." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.779, + 0.471, + 0.855 + ], + "angle": 0, + "content": "View Transformation (VT) is the key component that converts multi-camera features to BEV, which has been heavily studied in previous works [15, 20, 17, 24, 10, 6, 21, 9]. Existing VT methods can be categorized into geometry-based [13, 19, 17, 9, 18, 30] and learning-based meth" + }, + { + "type": "image", + "bbox": [ + 0.522, + 0.268, + 0.872, + 0.373 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.523, + 0.375, + 0.872, + 0.479 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.482, + 0.895, + 0.538 + ], + "angle": 0, + "content": "Figure 1. The pipeline of Lift-Splat (upper) and our proposed MatrixVT (lower). We compress image features before VT to reduce memory footprint and calculation. Note that only standard operators are adopted in MatrixVT." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.567, + 0.895, + 0.748 + ], + "angle": 0, + "content": "ods [10, 20, 15]. Among these two categories, geometry-based methods show superior performance due to the use of geometric constraints. Lift-Splat [17], as a representative geometry-based VT, predicts categorical depth distribution for each pixel and \"lift\" the corresponding features into 3D space according to the predicted depth. These feature vectors are then gathered into pre-defined grids on a reference BEV plane (i.e., \"splat\") to form the BEV feature (Fig. 1, upper). The Lift-Splat-based VT has shown great potential to produce high-quality BEV features, achieving remarkable performance on object detection [9, 5] and map segmentation tasks." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.896, + 0.903 + ], + "angle": 0, + "content": "Despite the effectiveness of Lift-Splat-like VT [9], two issues remain. First, the \"splat\" operation is not universally feasible. Existing implementations of \"splat\" relies on either the \"cumsum trick\" [17, 6] that is highly inefficient, or customized operators [9] that can only be used on specific devices, making application of BEV perception methods costly. Second, the size of \"lifted\" multi-view image features is huge, becoming the memory bottleneck of BEV models. These two issues lead to a heavy burden on BEV methods during both the training and inference phases. As" + }, + { + "type": "page_footnote", + "bbox": [ + 0.076, + 0.863, + 0.471, + 0.901 + ], + "angle": 0, + "content": "*Corresponding author. This research was supported by National Key R&D Program of China (No. 2017YFA0700800) and Beijing Academy of Artificial Intelligence (BAAI)." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8548" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.121 + ], + "angle": 0, + "content": "a result, the drawbacks of existing view transformers limit the broad application of autonomous driving technology" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.122, + 0.468, + 0.242 + ], + "angle": 0, + "content": "In this work, we propose a novel VT method to address the above problems. MatrixVT is proposed based on the fact that the VT can be viewed as a feature transportation process. In that case, the BEV feature can be viewed as the MatMul between the \"lifted\" feature and a transporting matrix, namely Feature Transporting Matrix (FTM). We thus generalize the Lift-Splat VT into a simple form and eliminate specialized operators." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.243, + 0.468, + 0.544 + ], + "angle": 0, + "content": "However, transformation with FTM is a kind of degradation — the mapping between the 3D space and BEV grids is extreme sparse, leading to the huge size of FTM and poor efficiency. Prior works [9, 18] seek customized operators, successfully avoiding such sparsity. In this paper, we argue that there are other solutions to the problem of sparse mapping. First, we propose Prime Extraction. Motivated by an observation that the height (vertical) dimension of images is less informative in autonomous driving (see Sec. 3.2), we compress the image features along this dimension before VT. Second, we adopt matrix decomposition to reduce the sparsity of FTM. The proposed Ring & Ray Decomposition orthogonally decomposes the FTM into two separate matrices, each encoding the distance and direction of the ego-centric polar coordinate. This decomposition also allows us to reformulate our pipeline into a mathematically equivalent but more efficient one (Fig. 1, lower). These two techniques reduce memory footprint and calculation during VT by hundreds of times, enabling MatrixVT to be more efficient than existing methods." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.545, + 0.468, + 0.709 + ], + "angle": 0, + "content": "The proposed MatrixVT inherits the advantages of the Lift-Splat [17] paradigm while being much more memory efficient and fast. Extensive experimental results show that MatrixVT is 2-to-8 times faster than previous methods [9, 6] and saves up to \\(97\\%\\) memory footprint among different settings. Meanwhile, the perception model with MatrixVT achieves \\(46.6\\%\\) mAP and \\(56.2\\%\\) NDS for object detection and \\(46.2\\%\\) mIoU for vehicle segmentation on the nuScenes [2] val set, which is comparable to the state-of-the-art performance [9]. We conclude our main contributions as follows:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.718, + 0.468, + 0.763 + ], + "angle": 0, + "content": "- We propose a new description of multi-camera to BEV transformation — using the Feature Transportation Matrix (FTM), which is a more general representation." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.772, + 0.468, + 0.817 + ], + "angle": 0, + "content": "- To solve the sparse mapping problem, we propose Prime Extraction and the Ring & Ray Decomposition, boosting VT with FTM by a huge margin." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.825, + 0.468, + 0.901 + ], + "angle": 0, + "content": "- Extensive experiments demonstrate that MatrixVT yields comparable performance to the state-of-the-art method on the nuScenes object detection and map segmentation tasks while being more efficient and generally applicable." + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.718, + 0.468, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.09, + 0.65, + 0.105 + ], + "angle": 0, + "content": "2. Related Works" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.115, + 0.698, + 0.132 + ], + "angle": 0, + "content": "2.1. Visual 3D Perception" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.139, + 0.892, + 0.23 + ], + "angle": 0, + "content": "Camera-based perception [28, 27, 6, 10, 11] is the most commonly used method for various scenarios due to its low cost and high accessibility. Comparing with 2D perception (object detection [26], semantic segmentation [22], etc.), 3D perception requires additional prediction of the depth information which is a naturally ill-posed problem [21]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.231, + 0.892, + 0.547 + ], + "angle": 0, + "content": "Existing works either predict the depth information explicitly or implicitly. FCOS3D [28] simply extends the structure of the classic 2D object detector [26], predicting pixel-wise depth explicitly using an extra sub-net. CaDDN [18] proposes treating depth prediction as a classification task rather than a regression task, and projecting image feature into Bird's-Eye-View (BEV) space to achieve unified modeling of detection and depth prediction. BEVDepth [9] proposes a heavy and well-designed subnet for depth prediction, achieving outstanding performance among other 3D object detectors. Meanwhile, methods like PON [20], BirdGAN [24], and EFT [23] use fully learnable networks to implement feature transformation, learning object depth implicitly using segmentation or detection supervision. Among theme, EFT [23] proposes using a learnable matrix for VT, which bears some resemblance, in form, to the Feature Transformation Matrix (FTM) we proposed. However, the matrices we designed for MatrixVT contains clear physical meanings with explicit depth modeling, and there are significant differences in their applicable scenarios and methods of use." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.56, + 0.768, + 0.575 + ], + "angle": 0, + "content": "2.2. Perception in Bird's-Eye-View" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.583, + 0.892, + 0.793 + ], + "angle": 0, + "content": "The concept of BEV is firstly proposed for processing LiDAR point cloud [33, 7, 31, 32], and found effective for fusing multi-view image features. The core component of vision-based BEV paradigm is the view-transformation. OFT [21] firstly propose mapping image feature from Perspective View into BEV using camera parameters. This method projects a reference point from a BEV grid to the image plane, and sample corresponding features back to the BEV grid. Following this work, BEVFormer [10] proposes using Attention module to sample features around the reference point. These methods fail to distinguish BEV grids that are projected to the same position on the image plane, thus showing inferior performance than depth-based methods." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Depth-based methods, represented by LSS [17] and CaDDN [18], predict categorical depth for each pixel, the extracted image feature on a specific pixel is then projected into 3D space by doing per-pixel outer product with corresponding depth. The projected high-dimensional tensor is then \"collapsed\" to a BEV reference plane using convolution [18], Pillar Pooling [17, 6], or Voxel Pooling [9]. Lift-" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8549" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.244 + ], + "angle": 0, + "content": "Splat based methods [17, 9, 6] show outstanding performance for downstream tasks but introduce two extra problems. Firstly, the intermediate representation of image features is large and in-efficient, making training and application of these methods difficult. Secondly, the Pillar Pooling [17] introduces random memory access, which is slow and device-demanding (extremely slow on general-purpose devices). In this paper, we propose a new depth-based view transformation to overcome these problems while retaining the ability to produce high-quality BEV features." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.257, + 0.191, + 0.273 + ], + "angle": 0, + "content": "3. MatrixVT" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.282, + 0.47, + 0.433 + ], + "angle": 0, + "content": "The MatrixVT is a simple view transformer based on the depth-based VT paradigm. In Sec. 3.1, we first revisit existing Lift-Splat transformation [17, 9] and introduce the concept of Feature Transporting Matrix (FTM) together with the sparse mapping problem. Then, techniques proposed to solve the problem of sparse mapping i.e., Prime Extraction (Sec. 3.2) and Ring & Ray Decomposition (Sec. 3.3), are introduced. In Sec. 3.4, we designate the novel VT method utilizing the aforementioned techniques as MatrixVT, and elaborate its overall pipeline." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.433, + 0.471, + 0.51 + ], + "angle": 0, + "content": "For clarity, we use letters of the normal script \\((e.g. F)\\) for tensors, the Roman script for matrices \\((e.g. M)\\), and Bold script \\((e.g. v)\\) for vectors. Besides, \\(A \\cdot B\\) denotes Matrix Multiplication (MatMul), \\(A \\odot B\\) denotes Hadamard Product, and \\(a \\otimes b\\) denotes outer product." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.52, + 0.21, + 0.535 + ], + "angle": 0, + "content": "3.1. Background" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.543, + 0.473, + 0.771 + ], + "angle": 0, + "content": "Lift-Splat-like methods exploit the idea of pseudo-LiDAR [29] and LiDAR-based BEV methods [33, 7] for View Transformation. Image features are \"lifted\" to 3D space and processed like point cloud. We define \\(N_{c}\\) as the number of cameras for a specific scene; \\(N_{d}\\) as the number of depth bins; \\(H_{I}\\) and \\(W_{I}\\) to be the height and width of image features; \\(H_{B}\\) and \\(W_{B}\\) to be the height and width of BEV features (i.e., shape of BEV grids); \\(C\\) to be the number of feature channels. Consequently, let multi-view image features to be \\(F \\in \\mathbb{R}^{N_c \\times H_I \\times W_I \\times C}\\); categorical depth to be \\(D \\in \\mathbb{R}^{N_c \\times H_I \\times W_I \\times N_d}\\); BEV features to be \\(F_{BEV} \\in \\mathbb{R}^{H_B \\times W_B \\times C}\\) (initialized to zeros). The Lift-Splat VT first \"lift\" the \\(F\\) into 3D space by doing per-pixel outer product with \\(D\\), obtaining the high-dimensional intermediate tensor \\(F_{inter} \\in \\mathbb{R}^{N_c \\times H_I \\times W_I \\times N_d \\times C}\\)." + }, + { + "type": "equation", + "bbox": [ + 0.085, + 0.78, + 0.47, + 0.8 + ], + "angle": 0, + "content": "\\[\nF _ {i n t e r} = \\left\\{F _ {i n t e r} ^ {h, w} \\right\\} _ {H _ {I}, W _ {I}} = \\left\\{\\boldsymbol {F} ^ {h, w} \\cdot \\left(\\boldsymbol {D} ^ {h, w}\\right) ^ {T} \\right\\} _ {H _ {I}, W _ {I}} (1)\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.471, + 0.9 + ], + "angle": 0, + "content": "The intermediate tensor can be treated as \\( N_{c} \\times H_{I} \\times W_{I} \\times N_{d} \\) feature vectors, each vector corresponding to a geometric coordinate. The \"splat\" operation is then adopted using operators like Pillar Pooling [17], during which each feature vector is summed to a BEV grid according to geometric coordinates." + }, + { + "type": "image", + "bbox": [ + 0.523, + 0.098, + 0.88, + 0.353 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.356, + 0.892, + 0.398 + ], + "angle": 0, + "content": "Figure 2. Response strengths along vertical and horizontal dimensions. For autonomous driving, the variance of response on the width dimension is higher than height dimension." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.422, + 0.892, + 0.543 + ], + "angle": 0, + "content": "We find that the \"splat\" operation is a fixed mapping between the intermediate tensor and BEV grids. Therefore, we use a Feature Transporting Matrix \\(\\mathbf{M}_{\\mathrm{FT}} \\in \\mathbb{R}^{(H_B \\times W_B) \\times (N_c \\times H_I \\times W_I \\times N_d)}\\) to describe this mapping. The FTM can be strictly equal to Pillar Pooling in LSS [17] or encodes different sampling rules (i.e., Gaussian sampling). The FTM enables feature transportation with Matrix Multiplication (MatMul):" + }, + { + "type": "equation", + "bbox": [ + 0.621, + 0.555, + 0.891, + 0.571 + ], + "angle": 0, + "content": "\\[\n\\mathrm {F} _ {\\text {B E V}} = \\mathrm {M} _ {\\mathrm {F T}} \\cdot \\mathrm {F} _ {\\text {i n t e r}} \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.58, + 0.891, + 0.627 + ], + "angle": 0, + "content": "where \\(\\mathrm{F}_{\\mathrm{inter}}\\in \\mathbb{R}^{(N_c\\times H_I\\times W_I\\times N_d)\\times C}\\) is the \"lifted\" feature \\(F_{inter}\\) in matrix format, \\(\\mathrm{F_{BEV}}\\in \\mathbb{R}^{(H_B\\times W_B)\\times C}\\) is the BEV feature \\(F_{BEV}\\) in matrix format." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.628, + 0.892, + 0.747 + ], + "angle": 0, + "content": "Replacing the \"splat\" operation with FTM eliminates the need for customized operators. However, the sparse mapping between the 3D space and BEV grids can lead to a massive and highly sparse FTM, which harms the efficiency of matrix-based VT. To address the sparse mapping problem without customized operators, we propose two techniques to reduce the sparsity of FTM and speed up the transformation." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.757, + 0.862, + 0.773 + ], + "angle": 0, + "content": "3.2. Prime Extraction for Autonomous Driving" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.892, + 0.901 + ], + "angle": 0, + "content": "The high-dimensional intermediate tensor is the primary cause of the sparse mapping and the low efficiency of Lift-Splat-like VT. An intuitive way to reduce sparsity is reducing the size of \\( F_{inter} \\). In the context of autonomous driving, a notable observation can lead to feature compression. As can be seen in Fig. 2, the height dimension of camera images contains less informative data. The height dimension is filled with redundant and background features, making it" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8550" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.088, + 0.092, + 0.452, + 0.369 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.373, + 0.473, + 0.43 + ], + "angle": 0, + "content": "Figure 3. The Prime Extraction module. The categorical depth is reduced guided by Prime Depth Attention, while the image feature is reduced by Prime Feature Extractor (PFE), which consists of MaxPooling and convolutions for refinement." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.457, + 0.47, + 0.517 + ], + "angle": 0, + "content": "ideal for feature compression. Therefore, we propose Prime Extraction, which is a compression technique that can be used in autonomous driving and other scenarios with information redundancy of this nature." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.52, + 0.47, + 0.717 + ], + "angle": 0, + "content": "As shown in Fig. 3, the Prime Extraction module predicts Prime Depth Attention for each direction (a column of the tensor) guided by the image feature. It generates the Prime Depth as a weighted sum of categorical depth distributions. Meanwhile, the Prime Feature is obtained by the Prime Feature Extractor (PFE), which consists of position embedding, column-wise max-pooling, and convolutions for refinement. By applying Prime Extraction to matrix-based VT, we successfully reduce the FTM to \\(\\mathbf{M}_{\\mathrm{FT}}^{\\prime} \\in \\mathbb{R}^{(H_B \\times W_B) \\times (N_c \\times W_I \\times N_d)}\\), which is \\(H_{I}\\) times smaller than the raw matrix. The pipeline of generating the BEV feature using the Prime Feature and the Prime Depth is demonstrated in Fig. 4 (yellow box)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.718, + 0.47, + 0.854 + ], + "angle": 0, + "content": "The prime extraction is motivated by an observation: The image feature's height dimension has a lower response variance than the width dimension. This observation indicates that this dimension contains less information than the width dimension. We thus propose to compress image features on the height dimension. Previous works have also exploited reducing the height dimension of image features [20, 1], but we firstly propose compressing both image features and corresponding depth to boost VT." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.471, + 0.901 + ], + "angle": 0, + "content": "In Sec. 4.4, we will show that the extracted Prime Feature and Prime Depth effectively retain valuable information from the raw feature and produce BEV features of the" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.893, + 0.152 + ], + "angle": 0, + "content": "same high quality as the raw feature. Moreover, the Prime Extraction technique can be individually adapted to existing Lift-Splat-like VTs to enhance their efficiency at almost no performance cost." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.162, + 0.78, + 0.178 + ], + "angle": 0, + "content": "3.3. \"Ring and Ray\" Decomposition" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.185, + 0.893, + 0.518 + ], + "angle": 0, + "content": "The sparsity of FTM can be further reduced by matrix decomposition. To this end, we propose the \"Ring & Ray\" Decomposition. Without loss of generality, we can set the \\(N_{c}\\) to 1 and view \\(\\mathbf{M}_{\\mathrm{FT}}^{\\prime}\\) as a tensor \\(M_{FT}^{\\prime}\\). In that case, the shape of \\(M_{FT}^{\\prime}\\) would be \\(H_{B} \\times W_{B} \\times W_{I} \\times N_{d}\\). We note that its dimension of size \\(W_{I}\\) can be viewed as the direction in a polar coordinate, since each column of the image feature represents information of a specific direction. Likewise, the dimension of size \\(N_{d}\\) can be viewed as the distance in the polar coordinate. In other words, the image feature required for a specific BEV grid can be located by direction and distance. We thus propose to orthogonally decompose the \\(M_{FT}^{\\prime}\\) into two separate matrices, each encoding the directional or distance information. Specifically, we use a Ring Matrix \\(\\mathbf{M}_{\\mathrm{Ring}} \\in \\mathbb{R}^{N_d \\times (H_B \\times W_B)}\\) to encode distance information and a Ray Matrix \\(\\mathbf{M}_{\\mathrm{Ray}} \\in \\mathbb{R}^{W_I \\times (H_B \\times W_B)}\\) to encode directional information (see Appendix 1.1 for pseudo code). The Ring & Ray Decomposition effectively reduces the size of static parameters. The number of predefined parameters (size of FTM) is reduced from \\(W_{I} \\times N_{d} \\times H_{B} \\times W_{B}\\) to \\((W_{I} + N_{d}) \\times H_{B} \\times W_{B}\\), which is typically 30 to 50 times less1." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.518, + 0.892, + 0.579 + ], + "angle": 0, + "content": "Then we show how to use these two matrices for VT. Given the Prime Feature and Prime Depth, we first do the per-pixel outer product of them as in Lift-Splat to obtain the \"lifted feature\" \\( F_{inter} \\in \\mathbb{R}^{W_I \\times N_d \\times C} \\)." + }, + { + "type": "equation", + "bbox": [ + 0.545, + 0.59, + 0.892, + 0.609 + ], + "angle": 0, + "content": "\\[\nF _ {i n t e r} = \\left\\{F _ {i n t e r} ^ {w} \\right\\} _ {W _ {I}} = \\left\\{\\boldsymbol {F} ^ {\\boldsymbol {w}} \\otimes \\left(\\boldsymbol {D} ^ {\\boldsymbol {w}}\\right) ^ {T} \\right\\} _ {W _ {I}} \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.619, + 0.892, + 0.74 + ], + "angle": 0, + "content": "Then, as illustrated in Fig. 4, instead of using \\( \\mathrm{M}_{\\mathrm{FT}}' \\) to directly transform it into a BEV feature (yellow box), we transpose \\( F_{inter} \\), view it as a matrix \\( \\mathrm{F}_{\\mathrm{inter}} \\in \\mathbb{R}^{N_d \\times (W_I \\times C)} \\), and do MatMul between the Ring Matrix and \\( \\mathrm{F}_{\\mathrm{inter}} \\) to obtain an intermediate feature. The intermediate feature is then masked by doing a Hadamard Product with the Ray Matrix, summed on the dimension of \\( W_I \\) to obtain the BEV feature. (Fig. 4, blue box, summation omitted)." + }, + { + "type": "equation", + "bbox": [ + 0.581, + 0.753, + 0.891, + 0.77 + ], + "angle": 0, + "content": "\\[\n\\mathrm {F} _ {\\text {i n t e r}} ^ {*} = \\mathrm {M} _ {\\text {R a y}} \\odot (\\mathrm {M} _ {\\text {R i n g}} \\cdot \\mathrm {F} _ {\\text {i n t e r}}) \\tag {4}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.628, + 0.773, + 0.891, + 0.803 + ], + "angle": 0, + "content": "\\[\nF _ {B E V} = \\sum_ {w} F _ {\\text {i n t e r}} ^ {* w} \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.815, + 0.882, + 0.833 + ], + "angle": 0, + "content": "where \\(F_{inter}^{*}\\in \\mathbb{R}^{W_I\\times C\\times H_B\\times W_B}\\) is \\(\\mathrm{F}_{\\mathrm{inter}}^{*}\\) in tensor form." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.833, + 0.892, + 0.877 + ], + "angle": 0, + "content": "However, this decomposition do not reduce the FLOPs during VT and introduces the Intermediate Feature in Fig. 4 (blue) whose size if huge and depends on feature channel" + }, + { + "type": "page_footnote", + "bbox": [ + 0.516, + 0.887, + 0.802, + 0.9 + ], + "angle": 0, + "content": "Under feature width 44 and 88, with 112 depth bins." + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "8551" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.088, + 0.095, + 0.43, + 0.111 + ], + "angle": 0, + "content": "Pipelines of View Transformation Using Matrices" + }, + { + "type": "image", + "bbox": [ + 0.087, + 0.112, + 0.891, + 0.335 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.338, + 0.894, + 0.395 + ], + "angle": 0, + "content": "Figure 4. View Transformation using matrices. We first extract features from the image and predict categorical depth for each pixel. The obtained feature and depth are sent to the Prime Extraction module for compression. With the compressed Prime Feature and the Prime Depth, we \"lift\" the 1D Prime Feature into 2D space using Prime Depth. The \"lifted feature\" is then transformed into the BEV feature by MatMul with FTM or the decomposed Ring & Ray matrices." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.419, + 0.47, + 0.465 + ], + "angle": 0, + "content": "\\(C\\). To reduce the calculation and memory footprint during VT, we combine Eq. 3 to Eq. 5 and rewrite them in a mathematically equivalent form (see Appendix 1.2 for proof):" + }, + { + "type": "equation", + "bbox": [ + 0.153, + 0.474, + 0.469, + 0.492 + ], + "angle": 0, + "content": "\\[\n\\mathrm {F} _ {\\mathrm {B E V}} = \\mathrm {F} \\cdot \\left(\\mathrm {M} _ {\\text {R a y}} \\odot \\left(\\mathrm {M} _ {\\text {R i n g}} \\cdot \\mathrm {D}\\right)\\right) \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.5, + 0.469, + 0.576 + ], + "angle": 0, + "content": "With this reformulation, we reduce the calculation during VT from \\(2 \\times W_{I} \\times C \\times N_{d} \\times H_{B} \\times W_{B}\\) FLOPs to \\(2(C + N_{d} + 1) \\times W_{I} \\times H_{B} \\times W_{B}\\) FLOPs; the memory footprint is also reduced from \\(W_{I} \\times N_{d} \\times H_{B} \\times W_{B}\\) to \\((W_{I} + N_{d}) \\times H_{B} \\times W_{B}\\)." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.585, + 0.239, + 0.601 + ], + "angle": 0, + "content": "3.4. Overall Pipeline" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.608, + 0.469, + 0.683 + ], + "angle": 0, + "content": "With above techniques, we reduce the calculation and memory footprint using FTM by hundreds of times, making VT with FTM not only feasible but also efficient. Given the multi-view images for a specific scene, we conclude the overall pipeline of MatrixVT as follows:" + }, + { + "type": "text", + "bbox": [ + 0.09, + 0.692, + 0.469, + 0.722 + ], + "angle": 0, + "content": "1. We first use an image backbone to extract image features from each image." + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.731, + 0.469, + 0.776 + ], + "angle": 0, + "content": "2. Then, a depth predictor is adopted to predict categorical depth distribution for each feature pixel to obtain the depth prediction." + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.786, + 0.469, + 0.846 + ], + "angle": 0, + "content": "3. After that, we send each image feature and corresponding depth to the Prime Extraction module, obtaining the Prime Feature and the Prime Depth, which is the compressed feature and depth." + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.856, + 0.469, + 0.901 + ], + "angle": 0, + "content": "4. Finally, with the Prime Feature, Prime Depth, and the pre-defined Ring & Ray Matrices, we use Eq. 6 (see also Fig. 1, lower) to obtain the BEV feature." + }, + { + "type": "list", + "bbox": [ + 0.089, + 0.692, + 0.469, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.417, + 0.633, + 0.435 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.443, + 0.892, + 0.489 + ], + "angle": 0, + "content": "In this section, we compare the performance, latency, and memory footprint of MatrixVT and other existing VT methods on the nuScenes benchmark [2]." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.5, + 0.719, + 0.516 + ], + "angle": 0, + "content": "4.1. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.523, + 0.892, + 0.781 + ], + "angle": 0, + "content": "We conduct our experiments based on BEVDepth [9], the current state-of-the-art detector on the nuScenes benchmark. In order to conduct a fair comparison of performance and efficiency, we re-implement BEVDepth according to their paper. Unless otherwise specified, we use ResNet50 [3] and VoVNet2-99 [8] pre-trained on DD3D [16] as the image backbone and SECOND FPN [31] as the image neck and BEV neck. The input image adopts pre-processing and data augmentations same as in [9]. We use BEV feature size \\(128 \\times 128\\) for low input resolution and \\(256 \\times 256\\) for high resolution on detection. Segmentation experiments use \\(200 \\times 200\\) BEV resolution as in LSS [17]. We use the DepthNet [9] to predict categorical depth from \\(2\\mathrm{m}\\) to \\(58\\mathrm{m}\\) in nuScenes, with uniform 112 division. During training, CBGS [34] and model EMA are adopted. Models are trained to converge since MatrixVT converges a little slower than other methods, but no more than 30 epochs." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.792, + 0.761, + 0.807 + ], + "angle": 0, + "content": "4.2. Comparison of Performances" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.816, + 0.673, + 0.831 + ], + "angle": 0, + "content": "4.2.1 Object Detection" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.901 + ], + "angle": 0, + "content": "We conduct experiments under several settings to evaluate the performance of MatrixVT in Tab. 1 and Tab. 2. On the nuScenes benchmark, we first adopt the ResNet family as the backbone without applying multi-frame fusion." + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8552" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.09, + 0.894, + 0.319 + ], + "angle": 0, + "content": "
MethodBackboneResolutionMFmAP↑mATE↓mASE↓mAOE↓mAVE↓mAAE↓NDS↑
BEVDet [6]Res-50256 × 704×0.2860.7240.2780.5900.8730.2470.372
PETR [11]Res-50384 × 1056×0.3130.7680.2780.5640.9230.2250.381
BEVDepth [9]Res-50256 × 704×0.3370.6460.2710.5740.8380.2200.414
MatrixVTRes-50256 × 704×0.3360.6530.2710.4730.9030.2310.415
BEVDet [6]Res-101384 × 1056×0.3300.7020.2720.5340.9320.2510.396
FCOS3D [28]Res-101900 × 1600×0.3430.7250.2630.4221.2920.1530.415
PETR [11]Res-101512 × 1408×0.3570.7100.2700.4900.8850.2240.421
BEVFormer [10]R101-DCN900 × 1600×0.3750.7250.2720.3910.8020.2000.448
MatrixVTRes-101512 × 1408×0.3960.5770.2610.3970.8700.2070.467
BEVFormer [10]R101-DCN900 × 1600✓0.4160.6730.2740.3720.3940.1980.517
BEVDet4D [5]Swin-B640 × 1600✓0.4210.5790.2580.3290.3010.1910.545
BEVDepth [9]V2-99512 × 1408✓0.4640.5280.2540.3500.3540.1980.564
MatrixVTV2-99512 × 1408✓0.4660.5350.2600.3800.3420.1980.562
" + }, + { + "type": "table_caption", + "bbox": [ + 0.15, + 0.318, + 0.82, + 0.33 + ], + "angle": 0, + "content": "Table 1. Experimental results of object detection on the nuScenes val set. The \"MF\" indicates multi-frame fusion." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.367, + 0.472, + 0.424 + ], + "angle": 0, + "content": "
MethodBackbonemAP↑mAPH↑mAPL↑
BEVDepth [9]Res-500.2900.2080.253
MatrixVTRes-500.3040.2150.259
" + }, + { + "type": "table_caption", + "bbox": [ + 0.081, + 0.424, + 0.432, + 0.437 + ], + "angle": 0, + "content": "Table 2. Performance of object detection on Waymo val set." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.476, + 0.47, + 0.658 + ], + "angle": 0, + "content": "MatrixVT achieves \\(33.6\\%\\) and \\(49.7\\%\\) mAP with ResNet-50 and ResNet-101, which is comparable to the BEVDepth [9] and surpasses other methods by a large margin. We then test the upper bound of MatrixVT by replacing the backbone with V2-99 [8] pre-trained on external data and applying multi-frame fusion. Under this setting, MatrixVT achieves \\(46.6\\%\\) mAP and \\(56.2\\%\\) NDS, which is also comparable to the BEVDepth. Further, we validate if MatrixVT can be generalize to other benchmark. We conduct experiments on the Waymo benchmark [25], results show that MatrixVT still showing comparable or even better performance under this setting." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.68, + 0.264, + 0.696 + ], + "angle": 0, + "content": "4.2.2 Map Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.705, + 0.471, + 0.903 + ], + "angle": 0, + "content": "We also conduct experiments on map segmentation tasks to validate the quality of the BEV feature generated by MatrixVT. To achieve this, we simply put a U-Net-like [22] segmentation head on the BEV feature. For fair comparison, we put the same head on the BEV feature of BEVDepth for experiments, and results are reported as \"BEVDepth-Seg\" in Tab. 3. It is worth noting that previous works achieve the best segmentation performance under different settings (different resolution, head structure, etc.); thus, we report the highest performance of each method. As can be seen from Tab. 3, the map segmentation performance of MatrixVT surpasses most existing methods on all three subtasks and is comparable to our baseline, BEVDepth." + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.367, + 0.892, + 0.481 + ], + "angle": 0, + "content": "
MethodIoU-Drive↑IoU-Lane↑IoU-Vehicle↑
LSS [17]0.7290.2000.321
FIERY [4]--0.382
M2BEV [30]0.7590.380-
BEVFormer [10]0.7750.2390.467
BEVDepth-Seg0.8270.4640.450
MatrixVT0.8350.4480.462
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.481, + 0.892, + 0.523 + ], + "angle": 0, + "content": "Table 3. Experimental results of BEV segmentation on the nuScenes val set. We implement map segmentation on the BEVDepth by placing a segmentation head on the BEV feature." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.56, + 0.727, + 0.575 + ], + "angle": 0, + "content": "4.3. Efficient Transformation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.583, + 0.892, + 0.825 + ], + "angle": 0, + "content": "We compare the efficiency of View Transformation in two dimensions: Speed and Memory Consumption. Note that we measure the latency and memory footprint (using fp32) of view transformers since these metrics are affected by backbone and head design. We take the CPU as a representative general-purpose device where customized operators are unavailable. For a fair comparison, we measure and compare the other two Lift-Splat-like view transformers. The LS-BEVDet is the accelerated transformation used in BEVDet (with default parameters); the LS-BEVDepth uses the CUDA [14] operator proposed in BEVDepth [9] that is not available on CPU and other platforms. To demonstrate the characteristics of different methods, we define six transformation settings, namely S1~S6, varies in image feature size, BEV feature size, and feature channels that are closely related to model performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.894, + 0.903 + ], + "angle": 0, + "content": "As can be seen in Fig. 5, the proposed MatrixVT boost the transformation significantly on the CPU, being 4 to 8 times faster than the LS-BEVDet[6]. On the CUDA platform [14], where customized operators enable faster transformation, MatrixVT still shows a much faster speed than" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8553" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.295, + 0.09, + 0.678, + 0.113 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.088, + 0.116, + 0.357, + 0.269 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.359, + 0.116, + 0.621, + 0.27 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.623, + 0.116, + 0.885, + 0.27 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.278, + 0.893, + 0.32 + ], + "angle": 0, + "content": "Figure 5. Latency (left, middle) and the number of intermediate parameters (right) of MatrixVT and two implementations of Lift-Splat, the S1~S6 denote transformation settings represented by image feature size \\((C\\times H_I\\times W_I)\\) to BEV feature size \\((C\\times H_B\\times W_B)\\). Note that the LS-BEVDet raises Out Of Memory error under S5 and S6 on CUDA. The LS-BEVDepth is not available without the CUDA platform." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.344, + 0.47, + 0.48 + ], + "angle": 0, + "content": "the LS-BEVDepth under most settings. Besides, we calculate the number of intermediate variables during VT as an indicator of extra memory footprint. For MatrixVT, these variables include the Ring Matrix, Ray Matrix, and intermediate matrix; for Lift-Splat, intermediate variables include the intermediate tensor and the predefined BEV grids. As illustrated in Fig. 5 (right), MatrixVT consumes 2 to 15 times less memory than LS-BEVDepth and 40 to 80 times less memory than LS-BEVDet." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.481, + 0.47, + 0.616 + ], + "angle": 0, + "content": "In Tab. 4, we adopt our proposed methods onto the BEVDepth step-by-step and evaluate improvements in memory footprint and latency. It can be seen that Prime Extraction effectively reduced memory footprint and latency by a large margin. For the low-resolution setting (Res-50 & 256), the Ring & Ray FTM further reduces the resource consumption. For the high-resolution setting (V2-99 & \\(512 \\times 1408\\)), the application of Ring & Ray FTM enabled VT without custom operators at cost of extra computation." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.625, + 0.216, + 0.64 + ], + "angle": 0, + "content": "4.4. Effectiveness" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.648, + 0.47, + 0.692 + ], + "angle": 0, + "content": "In this section, we validate the effectiveness of the proposed methods by performance comparison and visualization." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.711, + 0.295, + 0.725 + ], + "angle": 0, + "content": "4.4.1 Effects on Performance" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.471, + 0.901 + ], + "angle": 0, + "content": "As mentioned in Sec. 3.2, we argue that the features and corresponding depths can be compressed with little or no information loss. We thus individually adopt the Prime Extraction and the Ring & Ray FTM onto the BEVDepth [9] to verify their effectiveness. To adopt Prime Extraction individually, we compress image features and the depths before the common Lift-Splat. As shown in Tab. 4, the BEVDepth with our improvements achieves \\(41.5\\%\\) NDS with Res-50 and \\(56.2\\%\\) NDS with VovNetv2-99 [8], which is comparable to the baseline. Thus, we argue that Prime Extraction effectively retained key information from raw features, and" + }, + { + "type": "table", + "bbox": [ + 0.515, + 0.342, + 0.88, + 0.469 + ], + "angle": 0, + "content": "
BackbonePERRNDSMem.Lat. (ms)
Res-500.416528M1.79
Res-50✓0.41694M1.42
Res-50✓✓0.41583M1.33
V2-990.5642.14G8.85
V2-99✓0.563405M2.04
V2-99✓✓0.562498M3.19
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.469, + 0.892, + 0.523 + ], + "angle": 0, + "content": "Table 4. Effects of using Prime Extraction (PE) and Ring & Ray FTM (RR) on BEVDepth. The memory consumption and latency reported is the memory footprint and time duration on PyTorch during View Transformation (VT)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.563, + 0.892, + 0.593 + ], + "angle": 0, + "content": "the application of Ring & Ray FTM would not harm the final performance." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.616, + 0.825, + 0.631 + ], + "angle": 0, + "content": "4.4.2 Prime Information in Object Detection" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.641, + 0.892, + 0.807 + ], + "angle": 0, + "content": "We then delve into the mechanism of Prime Extraction by visualization. Fig. 6 shows the inputs and outputs of the Prime Extraction module. It can be seen that the Prime Extraction module trained on different tasks focusing on different information. The Prime Depth Attention in object detection focuses on foreground objects. Thus the Prime Depth retained the depth of objects while ignoring the depth of the background. Also, it can be seen from the yellow car in the second column, which is obscured by three pedestrians. Prime Extraction effectively distinguishes these objects at different depths." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.831, + 0.84, + 0.846 + ], + "angle": 0, + "content": "4.4.3 Prime Information in Map Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.893, + 0.901 + ], + "angle": 0, + "content": "For the map segmentation task, we take lane segmentation as an example — the Prime Extraction module focus on lane and road that is closely related to this task. However, since" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8554" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.091, + 0.094, + 0.895, + 0.379 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.381, + 0.893, + 0.41 + ], + "angle": 0, + "content": "Figure 6. Depth Prediction, Prime Depth Attention, and Prime Depth for object detection and lane segmentation task. The categorical depth prediction is illustrated using distances with largest probability, while the Prime Depth is illustrated by raw probability values." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.434, + 0.473, + 0.556 + ], + "angle": 0, + "content": "the area of the target category is a wide range covering several depth bins, the distribution of Prime Depth is uniform in the target area (see Fig. 6, 3rd and 4th columns). The observation indicates that Prime Extraction generates a new form of depth distribution that fits the map segmentation task. With the Prime Depth that is rather uniform, the same feature can be projected to multiple depth bins since they are occupied by the same category." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.57, + 0.331, + 0.585 + ], + "angle": 0, + "content": "4.5. Extraction of Prime Feature" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.596, + 0.47, + 0.686 + ], + "angle": 0, + "content": "In the Prime Feature Extractor, we propose using max pooling followed by several 1D convolutions to reduce and refine the image feature. Before reduction, the coordinate of each pixel is embedded into the feature as position embedding. We conduct experiments to validate the contribution of each design." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.688, + 0.47, + 0.854 + ], + "angle": 0, + "content": "A possible alternative of the max pooling is the CollapseConv as in [18] and [20], which merges the height dimension into the channel dimension and reduces the merged channel by linear projection. However, the design of CollapseConv brings some disadvantages. For example, the merged dimension is of size \\( C \\times H \\), which is high and requires extra memory transportation. To address these problems, we propose using max pooling to reduce the image feature in Prime Extraction. Tab. 5 shows that reduction using max pooling achieves even better performance than CollapseConv while eliminating these shortcomings." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.471, + 0.902 + ], + "angle": 0, + "content": "We also conduct experiments to show the effectiveness of the refine sub-net after reducing in Tab. 5. The results indicate that the refine sub-net plays a vital role in adapting" + }, + { + "type": "table", + "bbox": [ + 0.508, + 0.432, + 0.887, + 0.522 + ], + "angle": 0, + "content": "
ReductionRefinePos. Emb.mAPNDS
Max Pooling0.3280.393
Max Pooling✓0.3320.414
Max Pooling✓✓0.3360.415
CollapseConv✓✓0.3340.404
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.522, + 0.892, + 0.563 + ], + "angle": 0, + "content": "Table 5. Performance of MatrixVT with different feature reduction methods. The \"Refine\" indicates the refine convs, the \"Pos.Emb.\" indicates using front-view position embedding." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.601, + 0.892, + 0.677 + ], + "angle": 0, + "content": "the reduced feature to BEV space, without which a performance drop of \\(0.9\\%\\) mAP will occur. Finally, the experimental results in Tab. 5 have shown that the position embedding brings an improvement of \\(0.4\\%\\) mAP, which is also preferable." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.689, + 0.619, + 0.705 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.715, + 0.892, + 0.881 + ], + "angle": 0, + "content": "This paper proposes a new paradigm of View Transformation (VT) from multi-camera to Bird's-Eye-View. The proposed method, MatrixVT, generalizes VT into a feature transportation matrix. We then propose Prime Extraction, which eliminates the redundancy during transformation, and the Ring & Ray Decomposition, which simplifies and boost the transformation. While being faster and more efficient on both specialized devices like GPU and general-purpose devices like CPU, our extensive experiments on the nuScenes benchmark indicate that the MatrixVT offers comparable performance to the state-of-the-art method." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8555" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.175, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.47, + 0.199 + ], + "angle": 0, + "content": "[1] Xuyang Bai, Zeyu Hu, Xinge Zhu, Qingqiu Huang, Yilun Chen, Hongbo Fu, and Chiew-Lan Tai. Transfusion: Robust lidar-camera fusion for 3d object detection with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1090-1099, 2022. 1, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.201, + 0.472, + 0.298 + ], + "angle": 0, + "content": "[2] Holger Caesar, Varun Bankiti, Alex H. Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2020, Seattle, WA, USA, June 13-19, 2020, pages 11618-11628. IEEE, 2020. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.3, + 0.47, + 0.37 + ], + "angle": 0, + "content": "[3] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In 2016 IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2016, Las Vegas, NV, USA, June 27-30, 2016, pages 770-778. IEEE Computer Society, 2016. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.372, + 0.47, + 0.455 + ], + "angle": 0, + "content": "[4] Anthony Hu, Zak Murez, Nikhil Mohan, Sofia Dudas, Jeffrey Hawke, Vijay Badrinarayanan, Roberto Cipolla, and Alex Kendall. Fiery: Future instance prediction in bird's-eye view from surround monocular cameras. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 15273-15282, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.458, + 0.469, + 0.499 + ], + "angle": 0, + "content": "[5] Junjie Huang and Guan Huang. Bevdet4d: Exploit temporal cues in multi-camera 3d object detection. ArXiv preprint, abs/2203.17054, 2022. 1, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.501, + 0.47, + 0.557 + ], + "angle": 0, + "content": "[6] Junjie Huang, Guan Huang, Zheng Zhu, and Dalong Du. Bevdet: High-performance multi-camera 3d object detection in bird-eye-view. ArXiv preprint, abs/2112.11790, 2021. 1, 2, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.559, + 0.47, + 0.643 + ], + "angle": 0, + "content": "[7] Alex H. Lang, Sourabh Vora, Holger Caesar, Lubing Zhou, Jiong Yang, and Oscar Beijbom. Pointpillars: Fast encoders for object detection from point clouds. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 12697-12705. Computer Vision Foundation / IEEE, 2019. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.645, + 0.47, + 0.713 + ], + "angle": 0, + "content": "[8] Youngwan Lee and Jongyoul Park. Centermask: Real-time anchor-free instance segmentation. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2020, Seattle, WA, USA, June 13-19, 2020, pages 13903-13912. IEEE, 2020. 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.716, + 0.47, + 0.784 + ], + "angle": 0, + "content": "[9] Yinhao Li, Zheng Ge, Guanyi Yu, Jinrong Yang, Zengran Wang, Yukang Shi, Jianjian Sun, and Zeming Li. Bevdepth: Acquisition of reliable depth for multi-view 3d object detection. ArXiv preprint, abs/2206.10092, 2022. 1, 2, 3, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.787, + 0.469, + 0.857 + ], + "angle": 0, + "content": "[10] Zhiqi Li, Wenhai Wang, Hongyang Li, Enze Xie, Chonghao Sima, Tong Lu, Qiao Yu, and Jifeng Dai. BEV-Former: Learning Bird's-Eye-View Representation from Multi-Camera Images via Spatiotemporal Transformers. ArXiv preprint, abs/2203.17270, 2022. 1, 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.859, + 0.47, + 0.902 + ], + "angle": 0, + "content": "[11] Yingfei Liu, Tiancai Wang, Xiangyu Zhang, and Jian Sun. Petr: Position embedding transformation for multi-view 3d object detection. ArXiv preprint, abs/2203.05625, 2022. 2, 6" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.472, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.148 + ], + "angle": 0, + "content": "[12] Zhijian Liu, Haotian Tang, Alexander Amini, Xinyu Yang, Huizi Mao, Daniela Rus, and Song Han. Bevfusion: Multitask multi-sensor fusion with unified bird's-eye view representation. arXiv preprint arXiv:2205.13542, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.15, + 0.892, + 0.205 + ], + "angle": 0, + "content": "[13] Hanspeter A Mallot, Heinrich H Bülthoff, JJ Little, and Stefan Bohrer. Inverse perspective mapping simplifies optical flow computation and obstacle detection. Biological cybernetics, 64(3):177-185, 1991. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.207, + 0.892, + 0.234 + ], + "angle": 0, + "content": "[14] NVIDIA, Péter Vingelmann, and Frank H.P. Fitzek. Cuda, release: 10.2.89, 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.236, + 0.892, + 0.291 + ], + "angle": 0, + "content": "[15] Bowen Pan, Jiankai Sun, Ho Yin Tiga Leung, Alex Andonian, and Bolei Zhou. Cross-view semantic segmentation for sensing surroundings. IEEE Robotics and Automation Letters, 5(3):4867-4873, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.293, + 0.892, + 0.348 + ], + "angle": 0, + "content": "[16] Dennis Park, Rares Ambrus, Vitor Guizilini, Jie Li, and Adrien Gaidon. Is pseudo-lidar needed for monocular 3d object detection? In IEEE/CVF International Conference on Computer Vision (ICCV), 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.35, + 0.892, + 0.405 + ], + "angle": 0, + "content": "[17] Jonah Philion and Sanja Fidler. Lift, splat, shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3d. In European Conference on Computer Vision, pages 194-210. Springer, 2020. 1, 2, 3, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.407, + 0.892, + 0.476 + ], + "angle": 0, + "content": "[18] Cody Reading, Ali Harakeh, Julia Chae, and Steven L. Waslander. Categorical depth distribution network for monocular 3d object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 8555-8564, 2021. 1, 2, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.478, + 0.892, + 0.561 + ], + "angle": 0, + "content": "[19] Lennart Reiher, Bastian Lampe, and Lutz Eckstein. A sim2real deep learning approach for the transformation of images from multiple vehicle-mounted cameras to a semantically segmented image in bird's eye view. In 2020 IEEE 23rd International Conference on Intelligent Transportation Systems (ITSC), pages 1-7. IEEE, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.563, + 0.892, + 0.645 + ], + "angle": 0, + "content": "[20] Thomas Roddick and Roberto Cipolla. Predicting semantic map representations from images using pyramid occupancy networks. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2020, Seattle, WA, USA, June 13-19, 2020, pages 11135-11144. IEEE, 2020. 1, 2, 4, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.647, + 0.892, + 0.716 + ], + "angle": 0, + "content": "[21] Thomas Roddick, Alex Kendall, and Roberto Cipolla. Orthographic feature transform for monocular 3d object detection. In 30th British Machine Vision Conference 2019, BMVC 2019, Cardiff, UK, September 9-12, 2019, page 285. BMVA Press, 2019. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.718, + 0.892, + 0.787 + ], + "angle": 0, + "content": "[22] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image computing and computer-assisted intervention, pages 234-241. Springer, 2015. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.789, + 0.892, + 0.857 + ], + "angle": 0, + "content": "[23] Daeyun Shin, Zhile Ren, Erik B Sudderth, and Charless C Fowlkes. 3d scene reconstruction with multi-layer depth and epipolar transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2172-2182, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.859, + 0.892, + 0.902 + ], + "angle": 0, + "content": "[24] Siddharth Srivastava, Frederic Jurie, and Gaurav Sharma. Learning 2d to 3d lifting for object detection in 3d for autonomous vehicles. In 2019 IEEE/RSJ International Confer-" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8556" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.47, + 0.12 + ], + "angle": 0, + "content": "ence on Intelligent Robots and Systems (IROS), pages 4504-4511. IEEE, 2019. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.47, + 0.259 + ], + "angle": 0, + "content": "[25] Pei Sun, Henrik Kretzschmar, Xerxes Dotiwalla, Aurelien Chouard, Vijaysai Patnaik, Paul Tsui, James Guo, Yin Zhou, Yuning Chai, Benjamin Caine, Vijay Vasudevan, Wei Han, Jiquan Ngiam, Hang Zhao, Aleksei Timofeev, Scott Ettinger, Maxim Krivokon, Amy Gao, Aditya Joshi, Yu Zhang, Jonathon Shlens, Zhifeng Chen, and Dragomir Anguelov. Scalability in perception for autonomous driving: Waymo open dataset. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), June 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.262, + 0.47, + 0.33 + ], + "angle": 0, + "content": "[26] Zhi Tian, Chunhua Shen, Hao Chen, and Tong He. FCOS: fully convolutional one-stage object detection. In 2019 IEEE/CVF International Conference on Computer Vision, ICCV 2019, Seoul, Korea (South), October 27 - November 2, 2019, pages 9626-9635. IEEE, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.332, + 0.47, + 0.386 + ], + "angle": 0, + "content": "[27] Tai Wang, ZHU Xinge, Jiangmiao Pang, and Dahua Lin. Probabilistic and geometric depth: Detecting objects in perspective. In Conference on Robot Learning, pages 1475-1485. PMLR, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.389, + 0.47, + 0.444 + ], + "angle": 0, + "content": "[28] Tai Wang, Xinge Zhu, Jiangmiao Pang, and Dahua Lin. Fcos3d: Fully convolutional one-stage monocular 3d object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 913-922, 2021. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.446, + 0.47, + 0.541 + ], + "angle": 0, + "content": "[29] Yan Wang, Wei-Lun Chao, Divyansh Garg, Bharath Hariharan, Mark E. Campbell, and Kilian Q. Weinberger. Pseudolidar from visual depth estimation: Bridging the gap in 3d object detection for autonomous driving. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 8445-8453. Computer Vision Foundation / IEEE, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.543, + 0.47, + 0.611 + ], + "angle": 0, + "content": "[30] Enze Xie, Zhiding Yu, Daquan Zhou, Jonah Philion, Anima Anandkumar, Sanja Fidler, Ping Luo, and Jose M Alvarez. M^2bev: Multi-camera joint 3d detection and segmentation with unified birds-eye view representation. ArXiv preprint, abs/2204.05088, 2022. 1, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.614, + 0.47, + 0.653 + ], + "angle": 0, + "content": "[31] Yan Yan, Yuxing Mao, and Bo Li. Second: Sparsely embedded convolutional detection. Sensors, 18(10):3337, 2018. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.656, + 0.47, + 0.712 + ], + "angle": 0, + "content": "[32] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Center-based 3d object detection and tracking. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 11784-11793, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.714, + 0.47, + 0.782 + ], + "angle": 0, + "content": "[33] Yin Zhou and Oncel Tuzel. Voxelnet: End-to-end learning for point cloud based 3d object detection. In 2018 IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2018, Salt Lake City, UT, USA, June 18-22, 2018, pages 4490-4499. IEEE Computer Society, 2018. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.784, + 0.47, + 0.837 + ], + "angle": 0, + "content": "[34] Benjin Zhu, Zhengkai Jiang, Xiangxin Zhou, Zeming Li, and Gang Yu. Class-balanced grouping and sampling for point cloud 3d object detection. ArXiv preprint, abs/1908.09492, 2019. 5" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.837 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8557" + } + ] +] \ No newline at end of file diff --git a/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/3d8f338d-7ad3-414d-a017-25b8e25151fd_origin.pdf b/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/3d8f338d-7ad3-414d-a017-25b8e25151fd_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..eaa520266769d2b06298f2e1c6ec00a0e622dfeb --- /dev/null +++ b/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/3d8f338d-7ad3-414d-a017-25b8e25151fd_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:00317f697a0a061cf9b4fbd00a19a1f0a013340a90f3340bb2d85a851d580991 +size 3187519 diff --git a/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/full.md b/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/full.md new file mode 100644 index 0000000000000000000000000000000000000000..32733cfcef603d866d7f2997f29fd9dd0e13b96e --- /dev/null +++ b/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/full.md @@ -0,0 +1,279 @@ +# MatrixVT: Efficient Multi-Camera to BEV Transformation for 3D Perception + +Hongyu Zhou, Zheng Ge, Zeming Li, Xiangyu Zhang* MEGVII Technology + +{zhouhongyu, gezheng, lizeming, zhangxiangyu}@megvii.com + +# Abstract + +This paper proposes an efficient multi-camera to Bird's-Eye-View (BEV) view transformation method for 3D perception, dubbed MatrixVT. Existing view transformers either suffer from poor efficiency or rely on device-specific operators, hindering the broad application of BEV models. In contrast, our method generates BEV features efficiently with only convolutions and matrix multiplications (MatMul). Specifically, we propose describing the BEV feature as the MatMul of image feature and a sparse Feature Transporting Matrix (FTM). A Prime Extraction module is then introduced to compress the dimension of image features and reduce FTM's sparsity. Moreover, we propose the Ring & Ray Decomposition to replace the FTM with two matrices and reformulate our pipeline to reduce calculation further. Compared to existing methods, MatrixVT enjoys a faster speed and less memory footprint while remaining deploy-friendly. Extensive experiments on nuScenes and Waymo benchmarks demonstrate that our method is highly efficient but obtains results on par with the SOTA method in object detection and map segmentation tasks. + +# 1. Introduction + +Vision-centric 3D perception in Bird's-Eye-View (BEV) [17, 20, 24] has recently drawn extensive attention. Apart from their outstanding performance, the compact and unified feature representation in BEV facilitates straight-forward feature fusions [1, 5, 12, 10], and enables various downstream tasks (e.g. object detection [6, 9, 10], map segmentation [17, 30], motion planning, etc.) to be applied thereon easily. + +View Transformation (VT) is the key component that converts multi-camera features to BEV, which has been heavily studied in previous works [15, 20, 17, 24, 10, 6, 21, 9]. Existing VT methods can be categorized into geometry-based [13, 19, 17, 9, 18, 30] and learning-based meth + +![](images/fb432dea189edc91f47fda152fc823b97f4dc9a705573a076f8533d24976038c.jpg) + +![](images/2ae6134179487d9f3d9d7dd0f488ca92d55bf898131976f820bc1c245eec3d8e.jpg) +Figure 1. The pipeline of Lift-Splat (upper) and our proposed MatrixVT (lower). We compress image features before VT to reduce memory footprint and calculation. Note that only standard operators are adopted in MatrixVT. + +ods [10, 20, 15]. Among these two categories, geometry-based methods show superior performance due to the use of geometric constraints. Lift-Splat [17], as a representative geometry-based VT, predicts categorical depth distribution for each pixel and "lift" the corresponding features into 3D space according to the predicted depth. These feature vectors are then gathered into pre-defined grids on a reference BEV plane (i.e., "splat") to form the BEV feature (Fig. 1, upper). The Lift-Splat-based VT has shown great potential to produce high-quality BEV features, achieving remarkable performance on object detection [9, 5] and map segmentation tasks. + +Despite the effectiveness of Lift-Splat-like VT [9], two issues remain. First, the "splat" operation is not universally feasible. Existing implementations of "splat" relies on either the "cumsum trick" [17, 6] that is highly inefficient, or customized operators [9] that can only be used on specific devices, making application of BEV perception methods costly. Second, the size of "lifted" multi-view image features is huge, becoming the memory bottleneck of BEV models. These two issues lead to a heavy burden on BEV methods during both the training and inference phases. As + +a result, the drawbacks of existing view transformers limit the broad application of autonomous driving technology + +In this work, we propose a novel VT method to address the above problems. MatrixVT is proposed based on the fact that the VT can be viewed as a feature transportation process. In that case, the BEV feature can be viewed as the MatMul between the "lifted" feature and a transporting matrix, namely Feature Transporting Matrix (FTM). We thus generalize the Lift-Splat VT into a simple form and eliminate specialized operators. + +However, transformation with FTM is a kind of degradation — the mapping between the 3D space and BEV grids is extreme sparse, leading to the huge size of FTM and poor efficiency. Prior works [9, 18] seek customized operators, successfully avoiding such sparsity. In this paper, we argue that there are other solutions to the problem of sparse mapping. First, we propose Prime Extraction. Motivated by an observation that the height (vertical) dimension of images is less informative in autonomous driving (see Sec. 3.2), we compress the image features along this dimension before VT. Second, we adopt matrix decomposition to reduce the sparsity of FTM. The proposed Ring & Ray Decomposition orthogonally decomposes the FTM into two separate matrices, each encoding the distance and direction of the ego-centric polar coordinate. This decomposition also allows us to reformulate our pipeline into a mathematically equivalent but more efficient one (Fig. 1, lower). These two techniques reduce memory footprint and calculation during VT by hundreds of times, enabling MatrixVT to be more efficient than existing methods. + +The proposed MatrixVT inherits the advantages of the Lift-Splat [17] paradigm while being much more memory efficient and fast. Extensive experimental results show that MatrixVT is 2-to-8 times faster than previous methods [9, 6] and saves up to $97\%$ memory footprint among different settings. Meanwhile, the perception model with MatrixVT achieves $46.6\%$ mAP and $56.2\%$ NDS for object detection and $46.2\%$ mIoU for vehicle segmentation on the nuScenes [2] val set, which is comparable to the state-of-the-art performance [9]. We conclude our main contributions as follows: + +- We propose a new description of multi-camera to BEV transformation — using the Feature Transportation Matrix (FTM), which is a more general representation. +- To solve the sparse mapping problem, we propose Prime Extraction and the Ring & Ray Decomposition, boosting VT with FTM by a huge margin. +- Extensive experiments demonstrate that MatrixVT yields comparable performance to the state-of-the-art method on the nuScenes object detection and map segmentation tasks while being more efficient and generally applicable. + +# 2. Related Works + +# 2.1. Visual 3D Perception + +Camera-based perception [28, 27, 6, 10, 11] is the most commonly used method for various scenarios due to its low cost and high accessibility. Comparing with 2D perception (object detection [26], semantic segmentation [22], etc.), 3D perception requires additional prediction of the depth information which is a naturally ill-posed problem [21]. + +Existing works either predict the depth information explicitly or implicitly. FCOS3D [28] simply extends the structure of the classic 2D object detector [26], predicting pixel-wise depth explicitly using an extra sub-net. CaDDN [18] proposes treating depth prediction as a classification task rather than a regression task, and projecting image feature into Bird's-Eye-View (BEV) space to achieve unified modeling of detection and depth prediction. BEVDepth [9] proposes a heavy and well-designed subnet for depth prediction, achieving outstanding performance among other 3D object detectors. Meanwhile, methods like PON [20], BirdGAN [24], and EFT [23] use fully learnable networks to implement feature transformation, learning object depth implicitly using segmentation or detection supervision. Among theme, EFT [23] proposes using a learnable matrix for VT, which bears some resemblance, in form, to the Feature Transformation Matrix (FTM) we proposed. However, the matrices we designed for MatrixVT contains clear physical meanings with explicit depth modeling, and there are significant differences in their applicable scenarios and methods of use. + +# 2.2. Perception in Bird's-Eye-View + +The concept of BEV is firstly proposed for processing LiDAR point cloud [33, 7, 31, 32], and found effective for fusing multi-view image features. The core component of vision-based BEV paradigm is the view-transformation. OFT [21] firstly propose mapping image feature from Perspective View into BEV using camera parameters. This method projects a reference point from a BEV grid to the image plane, and sample corresponding features back to the BEV grid. Following this work, BEVFormer [10] proposes using Attention module to sample features around the reference point. These methods fail to distinguish BEV grids that are projected to the same position on the image plane, thus showing inferior performance than depth-based methods. + +Depth-based methods, represented by LSS [17] and CaDDN [18], predict categorical depth for each pixel, the extracted image feature on a specific pixel is then projected into 3D space by doing per-pixel outer product with corresponding depth. The projected high-dimensional tensor is then "collapsed" to a BEV reference plane using convolution [18], Pillar Pooling [17, 6], or Voxel Pooling [9]. Lift- + +Splat based methods [17, 9, 6] show outstanding performance for downstream tasks but introduce two extra problems. Firstly, the intermediate representation of image features is large and in-efficient, making training and application of these methods difficult. Secondly, the Pillar Pooling [17] introduces random memory access, which is slow and device-demanding (extremely slow on general-purpose devices). In this paper, we propose a new depth-based view transformation to overcome these problems while retaining the ability to produce high-quality BEV features. + +# 3. MatrixVT + +The MatrixVT is a simple view transformer based on the depth-based VT paradigm. In Sec. 3.1, we first revisit existing Lift-Splat transformation [17, 9] and introduce the concept of Feature Transporting Matrix (FTM) together with the sparse mapping problem. Then, techniques proposed to solve the problem of sparse mapping i.e., Prime Extraction (Sec. 3.2) and Ring & Ray Decomposition (Sec. 3.3), are introduced. In Sec. 3.4, we designate the novel VT method utilizing the aforementioned techniques as MatrixVT, and elaborate its overall pipeline. + +For clarity, we use letters of the normal script $(e.g. F)$ for tensors, the Roman script for matrices $(e.g. M)$ , and Bold script $(e.g. v)$ for vectors. Besides, $A \cdot B$ denotes Matrix Multiplication (MatMul), $A \odot B$ denotes Hadamard Product, and $a \otimes b$ denotes outer product. + +# 3.1. Background + +Lift-Splat-like methods exploit the idea of pseudo-LiDAR [29] and LiDAR-based BEV methods [33, 7] for View Transformation. Image features are "lifted" to 3D space and processed like point cloud. We define $N_{c}$ as the number of cameras for a specific scene; $N_{d}$ as the number of depth bins; $H_{I}$ and $W_{I}$ to be the height and width of image features; $H_{B}$ and $W_{B}$ to be the height and width of BEV features (i.e., shape of BEV grids); $C$ to be the number of feature channels. Consequently, let multi-view image features to be $F \in \mathbb{R}^{N_c \times H_I \times W_I \times C}$ ; categorical depth to be $D \in \mathbb{R}^{N_c \times H_I \times W_I \times N_d}$ ; BEV features to be $F_{BEV} \in \mathbb{R}^{H_B \times W_B \times C}$ (initialized to zeros). The Lift-Splat VT first "lift" the $F$ into 3D space by doing per-pixel outer product with $D$ , obtaining the high-dimensional intermediate tensor $F_{inter} \in \mathbb{R}^{N_c \times H_I \times W_I \times N_d \times C}$ . + +$$ +F _ {i n t e r} = \left\{F _ {i n t e r} ^ {h, w} \right\} _ {H _ {I}, W _ {I}} = \left\{\boldsymbol {F} ^ {h, w} \cdot \left(\boldsymbol {D} ^ {h, w}\right) ^ {T} \right\} _ {H _ {I}, W _ {I}} (1) +$$ + +The intermediate tensor can be treated as $N_{c} \times H_{I} \times W_{I} \times N_{d}$ feature vectors, each vector corresponding to a geometric coordinate. The "splat" operation is then adopted using operators like Pillar Pooling [17], during which each feature vector is summed to a BEV grid according to geometric coordinates. + +![](images/c35f78c0a1284a07e5b1b47e5e22fea5f606d0fa6d018ed8705abde2f0b82639.jpg) +Figure 2. Response strengths along vertical and horizontal dimensions. For autonomous driving, the variance of response on the width dimension is higher than height dimension. + +We find that the "splat" operation is a fixed mapping between the intermediate tensor and BEV grids. Therefore, we use a Feature Transporting Matrix $\mathbf{M}_{\mathrm{FT}} \in \mathbb{R}^{(H_B \times W_B) \times (N_c \times H_I \times W_I \times N_d)}$ to describe this mapping. The FTM can be strictly equal to Pillar Pooling in LSS [17] or encodes different sampling rules (i.e., Gaussian sampling). The FTM enables feature transportation with Matrix Multiplication (MatMul): + +$$ +\mathrm {F} _ {\text {B E V}} = \mathrm {M} _ {\mathrm {F T}} \cdot \mathrm {F} _ {\text {i n t e r}} \tag {2} +$$ + +where $\mathrm{F}_{\mathrm{inter}}\in \mathbb{R}^{(N_c\times H_I\times W_I\times N_d)\times C}$ is the "lifted" feature $F_{inter}$ in matrix format, $\mathrm{F_{BEV}}\in \mathbb{R}^{(H_B\times W_B)\times C}$ is the BEV feature $F_{BEV}$ in matrix format. + +Replacing the "splat" operation with FTM eliminates the need for customized operators. However, the sparse mapping between the 3D space and BEV grids can lead to a massive and highly sparse FTM, which harms the efficiency of matrix-based VT. To address the sparse mapping problem without customized operators, we propose two techniques to reduce the sparsity of FTM and speed up the transformation. + +# 3.2. Prime Extraction for Autonomous Driving + +The high-dimensional intermediate tensor is the primary cause of the sparse mapping and the low efficiency of Lift-Splat-like VT. An intuitive way to reduce sparsity is reducing the size of $F_{inter}$ . In the context of autonomous driving, a notable observation can lead to feature compression. As can be seen in Fig. 2, the height dimension of camera images contains less informative data. The height dimension is filled with redundant and background features, making it + +![](images/97bfd8c3e8fb7a389411074bad6122cdc7fea34b1433ce6a165d97782774cf53.jpg) +Figure 3. The Prime Extraction module. The categorical depth is reduced guided by Prime Depth Attention, while the image feature is reduced by Prime Feature Extractor (PFE), which consists of MaxPooling and convolutions for refinement. + +ideal for feature compression. Therefore, we propose Prime Extraction, which is a compression technique that can be used in autonomous driving and other scenarios with information redundancy of this nature. + +As shown in Fig. 3, the Prime Extraction module predicts Prime Depth Attention for each direction (a column of the tensor) guided by the image feature. It generates the Prime Depth as a weighted sum of categorical depth distributions. Meanwhile, the Prime Feature is obtained by the Prime Feature Extractor (PFE), which consists of position embedding, column-wise max-pooling, and convolutions for refinement. By applying Prime Extraction to matrix-based VT, we successfully reduce the FTM to $\mathbf{M}_{\mathrm{FT}}^{\prime} \in \mathbb{R}^{(H_B \times W_B) \times (N_c \times W_I \times N_d)}$ , which is $H_{I}$ times smaller than the raw matrix. The pipeline of generating the BEV feature using the Prime Feature and the Prime Depth is demonstrated in Fig. 4 (yellow box). + +The prime extraction is motivated by an observation: The image feature's height dimension has a lower response variance than the width dimension. This observation indicates that this dimension contains less information than the width dimension. We thus propose to compress image features on the height dimension. Previous works have also exploited reducing the height dimension of image features [20, 1], but we firstly propose compressing both image features and corresponding depth to boost VT. + +In Sec. 4.4, we will show that the extracted Prime Feature and Prime Depth effectively retain valuable information from the raw feature and produce BEV features of the + +same high quality as the raw feature. Moreover, the Prime Extraction technique can be individually adapted to existing Lift-Splat-like VTs to enhance their efficiency at almost no performance cost. + +# 3.3. "Ring and Ray" Decomposition + +The sparsity of FTM can be further reduced by matrix decomposition. To this end, we propose the "Ring & Ray" Decomposition. Without loss of generality, we can set the $N_{c}$ to 1 and view $\mathbf{M}_{\mathrm{FT}}^{\prime}$ as a tensor $M_{FT}^{\prime}$ . In that case, the shape of $M_{FT}^{\prime}$ would be $H_{B} \times W_{B} \times W_{I} \times N_{d}$ . We note that its dimension of size $W_{I}$ can be viewed as the direction in a polar coordinate, since each column of the image feature represents information of a specific direction. Likewise, the dimension of size $N_{d}$ can be viewed as the distance in the polar coordinate. In other words, the image feature required for a specific BEV grid can be located by direction and distance. We thus propose to orthogonally decompose the $M_{FT}^{\prime}$ into two separate matrices, each encoding the directional or distance information. Specifically, we use a Ring Matrix $\mathbf{M}_{\mathrm{Ring}} \in \mathbb{R}^{N_d \times (H_B \times W_B)}$ to encode distance information and a Ray Matrix $\mathbf{M}_{\mathrm{Ray}} \in \mathbb{R}^{W_I \times (H_B \times W_B)}$ to encode directional information (see Appendix 1.1 for pseudo code). The Ring & Ray Decomposition effectively reduces the size of static parameters. The number of predefined parameters (size of FTM) is reduced from $W_{I} \times N_{d} \times H_{B} \times W_{B}$ to $(W_{I} + N_{d}) \times H_{B} \times W_{B}$ , which is typically 30 to 50 times less1. + +Then we show how to use these two matrices for VT. Given the Prime Feature and Prime Depth, we first do the per-pixel outer product of them as in Lift-Splat to obtain the "lifted feature" $F_{inter} \in \mathbb{R}^{W_I \times N_d \times C}$ . + +$$ +F _ {i n t e r} = \left\{F _ {i n t e r} ^ {w} \right\} _ {W _ {I}} = \left\{\boldsymbol {F} ^ {\boldsymbol {w}} \otimes \left(\boldsymbol {D} ^ {\boldsymbol {w}}\right) ^ {T} \right\} _ {W _ {I}} \tag {3} +$$ + +Then, as illustrated in Fig. 4, instead of using $\mathrm{M}_{\mathrm{FT}}'$ to directly transform it into a BEV feature (yellow box), we transpose $F_{inter}$ , view it as a matrix $\mathrm{F}_{\mathrm{inter}} \in \mathbb{R}^{N_d \times (W_I \times C)}$ , and do MatMul between the Ring Matrix and $\mathrm{F}_{\mathrm{inter}}$ to obtain an intermediate feature. The intermediate feature is then masked by doing a Hadamard Product with the Ray Matrix, summed on the dimension of $W_I$ to obtain the BEV feature. (Fig. 4, blue box, summation omitted). + +$$ +\mathrm {F} _ {\text {i n t e r}} ^ {*} = \mathrm {M} _ {\text {R a y}} \odot (\mathrm {M} _ {\text {R i n g}} \cdot \mathrm {F} _ {\text {i n t e r}}) \tag {4} +$$ + +$$ +F _ {B E V} = \sum_ {w} F _ {\text {i n t e r}} ^ {* w} \tag {5} +$$ + +where $F_{inter}^{*}\in \mathbb{R}^{W_I\times C\times H_B\times W_B}$ is $\mathrm{F}_{\mathrm{inter}}^{*}$ in tensor form. + +However, this decomposition do not reduce the FLOPs during VT and introduces the Intermediate Feature in Fig. 4 (blue) whose size if huge and depends on feature channel + +![](images/5649bb5366d44480f42c3ea588f88dd7b376088d50546afcc108adc67a7bacb3.jpg) +Pipelines of View Transformation Using Matrices +Figure 4. View Transformation using matrices. We first extract features from the image and predict categorical depth for each pixel. The obtained feature and depth are sent to the Prime Extraction module for compression. With the compressed Prime Feature and the Prime Depth, we "lift" the 1D Prime Feature into 2D space using Prime Depth. The "lifted feature" is then transformed into the BEV feature by MatMul with FTM or the decomposed Ring & Ray matrices. + +$C$ . To reduce the calculation and memory footprint during VT, we combine Eq. 3 to Eq. 5 and rewrite them in a mathematically equivalent form (see Appendix 1.2 for proof): + +$$ +\mathrm {F} _ {\mathrm {B E V}} = \mathrm {F} \cdot \left(\mathrm {M} _ {\text {R a y}} \odot \left(\mathrm {M} _ {\text {R i n g}} \cdot \mathrm {D}\right)\right) \tag {6} +$$ + +With this reformulation, we reduce the calculation during VT from $2 \times W_{I} \times C \times N_{d} \times H_{B} \times W_{B}$ FLOPs to $2(C + N_{d} + 1) \times W_{I} \times H_{B} \times W_{B}$ FLOPs; the memory footprint is also reduced from $W_{I} \times N_{d} \times H_{B} \times W_{B}$ to $(W_{I} + N_{d}) \times H_{B} \times W_{B}$ . + +# 3.4. Overall Pipeline + +With above techniques, we reduce the calculation and memory footprint using FTM by hundreds of times, making VT with FTM not only feasible but also efficient. Given the multi-view images for a specific scene, we conclude the overall pipeline of MatrixVT as follows: + +1. We first use an image backbone to extract image features from each image. +2. Then, a depth predictor is adopted to predict categorical depth distribution for each feature pixel to obtain the depth prediction. +3. After that, we send each image feature and corresponding depth to the Prime Extraction module, obtaining the Prime Feature and the Prime Depth, which is the compressed feature and depth. +4. Finally, with the Prime Feature, Prime Depth, and the pre-defined Ring & Ray Matrices, we use Eq. 6 (see also Fig. 1, lower) to obtain the BEV feature. + +# 4. Experiments + +In this section, we compare the performance, latency, and memory footprint of MatrixVT and other existing VT methods on the nuScenes benchmark [2]. + +# 4.1. Implementation Details + +We conduct our experiments based on BEVDepth [9], the current state-of-the-art detector on the nuScenes benchmark. In order to conduct a fair comparison of performance and efficiency, we re-implement BEVDepth according to their paper. Unless otherwise specified, we use ResNet50 [3] and VoVNet2-99 [8] pre-trained on DD3D [16] as the image backbone and SECOND FPN [31] as the image neck and BEV neck. The input image adopts pre-processing and data augmentations same as in [9]. We use BEV feature size $128 \times 128$ for low input resolution and $256 \times 256$ for high resolution on detection. Segmentation experiments use $200 \times 200$ BEV resolution as in LSS [17]. We use the DepthNet [9] to predict categorical depth from $2\mathrm{m}$ to $58\mathrm{m}$ in nuScenes, with uniform 112 division. During training, CBGS [34] and model EMA are adopted. Models are trained to converge since MatrixVT converges a little slower than other methods, but no more than 30 epochs. + +# 4.2. Comparison of Performances + +# 4.2.1 Object Detection + +We conduct experiments under several settings to evaluate the performance of MatrixVT in Tab. 1 and Tab. 2. On the nuScenes benchmark, we first adopt the ResNet family as the backbone without applying multi-frame fusion. + +
MethodBackboneResolutionMFmAP↑mATE↓mASE↓mAOE↓mAVE↓mAAE↓NDS↑
BEVDet [6]Res-50256 × 704×0.2860.7240.2780.5900.8730.2470.372
PETR [11]Res-50384 × 1056×0.3130.7680.2780.5640.9230.2250.381
BEVDepth [9]Res-50256 × 704×0.3370.6460.2710.5740.8380.2200.414
MatrixVTRes-50256 × 704×0.3360.6530.2710.4730.9030.2310.415
BEVDet [6]Res-101384 × 1056×0.3300.7020.2720.5340.9320.2510.396
FCOS3D [28]Res-101900 × 1600×0.3430.7250.2630.4221.2920.1530.415
PETR [11]Res-101512 × 1408×0.3570.7100.2700.4900.8850.2240.421
BEVFormer [10]R101-DCN900 × 1600×0.3750.7250.2720.3910.8020.2000.448
MatrixVTRes-101512 × 1408×0.3960.5770.2610.3970.8700.2070.467
BEVFormer [10]R101-DCN900 × 1600✓0.4160.6730.2740.3720.3940.1980.517
BEVDet4D [5]Swin-B640 × 1600✓0.4210.5790.2580.3290.3010.1910.545
BEVDepth [9]V2-99512 × 1408✓0.4640.5280.2540.3500.3540.1980.564
MatrixVTV2-99512 × 1408✓0.4660.5350.2600.3800.3420.1980.562
+ +Table 1. Experimental results of object detection on the nuScenes val set. The "MF" indicates multi-frame fusion. + +
MethodBackbonemAP↑mAPH↑mAPL↑
BEVDepth [9]Res-500.2900.2080.253
MatrixVTRes-500.3040.2150.259
+ +MatrixVT achieves $33.6\%$ and $49.7\%$ mAP with ResNet-50 and ResNet-101, which is comparable to the BEVDepth [9] and surpasses other methods by a large margin. We then test the upper bound of MatrixVT by replacing the backbone with V2-99 [8] pre-trained on external data and applying multi-frame fusion. Under this setting, MatrixVT achieves $46.6\%$ mAP and $56.2\%$ NDS, which is also comparable to the BEVDepth. Further, we validate if MatrixVT can be generalize to other benchmark. We conduct experiments on the Waymo benchmark [25], results show that MatrixVT still showing comparable or even better performance under this setting. + +# 4.2.2 Map Segmentation + +We also conduct experiments on map segmentation tasks to validate the quality of the BEV feature generated by MatrixVT. To achieve this, we simply put a U-Net-like [22] segmentation head on the BEV feature. For fair comparison, we put the same head on the BEV feature of BEVDepth for experiments, and results are reported as "BEVDepth-Seg" in Tab. 3. It is worth noting that previous works achieve the best segmentation performance under different settings (different resolution, head structure, etc.); thus, we report the highest performance of each method. As can be seen from Tab. 3, the map segmentation performance of MatrixVT surpasses most existing methods on all three subtasks and is comparable to our baseline, BEVDepth. + +Table 2. Performance of object detection on Waymo val set. + +
MethodIoU-Drive↑IoU-Lane↑IoU-Vehicle↑
LSS [17]0.7290.2000.321
FIERY [4]--0.382
M2BEV [30]0.7590.380-
BEVFormer [10]0.7750.2390.467
BEVDepth-Seg0.8270.4640.450
MatrixVT0.8350.4480.462
+ +Table 3. Experimental results of BEV segmentation on the nuScenes val set. We implement map segmentation on the BEVDepth by placing a segmentation head on the BEV feature. + +# 4.3. Efficient Transformation + +We compare the efficiency of View Transformation in two dimensions: Speed and Memory Consumption. Note that we measure the latency and memory footprint (using fp32) of view transformers since these metrics are affected by backbone and head design. We take the CPU as a representative general-purpose device where customized operators are unavailable. For a fair comparison, we measure and compare the other two Lift-Splat-like view transformers. The LS-BEVDet is the accelerated transformation used in BEVDet (with default parameters); the LS-BEVDepth uses the CUDA [14] operator proposed in BEVDepth [9] that is not available on CPU and other platforms. To demonstrate the characteristics of different methods, we define six transformation settings, namely S1~S6, varies in image feature size, BEV feature size, and feature channels that are closely related to model performance. + +As can be seen in Fig. 5, the proposed MatrixVT boost the transformation significantly on the CPU, being 4 to 8 times faster than the LS-BEVDet[6]. On the CUDA platform [14], where customized operators enable faster transformation, MatrixVT still shows a much faster speed than + +![](images/167e5a7a753d5e47c4cf4bd2389f2e2cb15c5ca2c4e43949673d39d555a9f20e.jpg) + +![](images/ded93cdc4bf4aef54294406476dfc3d52bbbc10d04ae3ba608d09bb52dce2614.jpg) +Figure 5. Latency (left, middle) and the number of intermediate parameters (right) of MatrixVT and two implementations of Lift-Splat, the S1~S6 denote transformation settings represented by image feature size $(C\times H_I\times W_I)$ to BEV feature size $(C\times H_B\times W_B)$ . Note that the LS-BEVDet raises Out Of Memory error under S5 and S6 on CUDA. The LS-BEVDepth is not available without the CUDA platform. + +![](images/eb4cee2494ada4bad1b00836d9134a3aea896492a8e3838bd96043a5d826731e.jpg) + +![](images/d546a5d926b953d7be6a60ab7721c0388dd5389fddd4a921c85a5a7925c74cb2.jpg) + +the LS-BEVDepth under most settings. Besides, we calculate the number of intermediate variables during VT as an indicator of extra memory footprint. For MatrixVT, these variables include the Ring Matrix, Ray Matrix, and intermediate matrix; for Lift-Splat, intermediate variables include the intermediate tensor and the predefined BEV grids. As illustrated in Fig. 5 (right), MatrixVT consumes 2 to 15 times less memory than LS-BEVDepth and 40 to 80 times less memory than LS-BEVDet. + +In Tab. 4, we adopt our proposed methods onto the BEVDepth step-by-step and evaluate improvements in memory footprint and latency. It can be seen that Prime Extraction effectively reduced memory footprint and latency by a large margin. For the low-resolution setting (Res-50 & 256), the Ring & Ray FTM further reduces the resource consumption. For the high-resolution setting (V2-99 & $512 \times 1408$ ), the application of Ring & Ray FTM enabled VT without custom operators at cost of extra computation. + +# 4.4. Effectiveness + +In this section, we validate the effectiveness of the proposed methods by performance comparison and visualization. + +# 4.4.1 Effects on Performance + +As mentioned in Sec. 3.2, we argue that the features and corresponding depths can be compressed with little or no information loss. We thus individually adopt the Prime Extraction and the Ring & Ray FTM onto the BEVDepth [9] to verify their effectiveness. To adopt Prime Extraction individually, we compress image features and the depths before the common Lift-Splat. As shown in Tab. 4, the BEVDepth with our improvements achieves $41.5\%$ NDS with Res-50 and $56.2\%$ NDS with VovNetv2-99 [8], which is comparable to the baseline. Thus, we argue that Prime Extraction effectively retained key information from raw features, and + +
BackbonePERRNDSMem.Lat. (ms)
Res-500.416528M1.79
Res-50✓0.41694M1.42
Res-50✓✓0.41583M1.33
V2-990.5642.14G8.85
V2-99✓0.563405M2.04
V2-99✓✓0.562498M3.19
+ +Table 4. Effects of using Prime Extraction (PE) and Ring & Ray FTM (RR) on BEVDepth. The memory consumption and latency reported is the memory footprint and time duration on PyTorch during View Transformation (VT). + +the application of Ring & Ray FTM would not harm the final performance. + +# 4.4.2 Prime Information in Object Detection + +We then delve into the mechanism of Prime Extraction by visualization. Fig. 6 shows the inputs and outputs of the Prime Extraction module. It can be seen that the Prime Extraction module trained on different tasks focusing on different information. The Prime Depth Attention in object detection focuses on foreground objects. Thus the Prime Depth retained the depth of objects while ignoring the depth of the background. Also, it can be seen from the yellow car in the second column, which is obscured by three pedestrians. Prime Extraction effectively distinguishes these objects at different depths. + +# 4.4.3 Prime Information in Map Segmentation + +For the map segmentation task, we take lane segmentation as an example — the Prime Extraction module focus on lane and road that is closely related to this task. However, since + +![](images/9b94ca56bbfb5a908de8c332f591a76603595681acf1e0f907267d2c73181453.jpg) +Figure 6. Depth Prediction, Prime Depth Attention, and Prime Depth for object detection and lane segmentation task. The categorical depth prediction is illustrated using distances with largest probability, while the Prime Depth is illustrated by raw probability values. + +the area of the target category is a wide range covering several depth bins, the distribution of Prime Depth is uniform in the target area (see Fig. 6, 3rd and 4th columns). The observation indicates that Prime Extraction generates a new form of depth distribution that fits the map segmentation task. With the Prime Depth that is rather uniform, the same feature can be projected to multiple depth bins since they are occupied by the same category. + +# 4.5. Extraction of Prime Feature + +In the Prime Feature Extractor, we propose using max pooling followed by several 1D convolutions to reduce and refine the image feature. Before reduction, the coordinate of each pixel is embedded into the feature as position embedding. We conduct experiments to validate the contribution of each design. + +A possible alternative of the max pooling is the CollapseConv as in [18] and [20], which merges the height dimension into the channel dimension and reduces the merged channel by linear projection. However, the design of CollapseConv brings some disadvantages. For example, the merged dimension is of size $C \times H$ , which is high and requires extra memory transportation. To address these problems, we propose using max pooling to reduce the image feature in Prime Extraction. Tab. 5 shows that reduction using max pooling achieves even better performance than CollapseConv while eliminating these shortcomings. + +We also conduct experiments to show the effectiveness of the refine sub-net after reducing in Tab. 5. The results indicate that the refine sub-net plays a vital role in adapting + +
ReductionRefinePos. Emb.mAPNDS
Max Pooling0.3280.393
Max Pooling✓0.3320.414
Max Pooling✓✓0.3360.415
CollapseConv✓✓0.3340.404
+ +Table 5. Performance of MatrixVT with different feature reduction methods. The "Refine" indicates the refine convs, the "Pos.Emb." indicates using front-view position embedding. + +the reduced feature to BEV space, without which a performance drop of $0.9\%$ mAP will occur. Finally, the experimental results in Tab. 5 have shown that the position embedding brings an improvement of $0.4\%$ mAP, which is also preferable. + +# 5. Conclusion + +This paper proposes a new paradigm of View Transformation (VT) from multi-camera to Bird's-Eye-View. The proposed method, MatrixVT, generalizes VT into a feature transportation matrix. We then propose Prime Extraction, which eliminates the redundancy during transformation, and the Ring & Ray Decomposition, which simplifies and boost the transformation. While being faster and more efficient on both specialized devices like GPU and general-purpose devices like CPU, our extensive experiments on the nuScenes benchmark indicate that the MatrixVT offers comparable performance to the state-of-the-art method. + +# References + +[1] Xuyang Bai, Zeyu Hu, Xinge Zhu, Qingqiu Huang, Yilun Chen, Hongbo Fu, and Chiew-Lan Tai. Transfusion: Robust lidar-camera fusion for 3d object detection with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1090-1099, 2022. 1, 4 +[2] Holger Caesar, Varun Bankiti, Alex H. Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2020, Seattle, WA, USA, June 13-19, 2020, pages 11618-11628. IEEE, 2020. 2, 5 +[3] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In 2016 IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2016, Las Vegas, NV, USA, June 27-30, 2016, pages 770-778. IEEE Computer Society, 2016. 5 +[4] Anthony Hu, Zak Murez, Nikhil Mohan, Sofia Dudas, Jeffrey Hawke, Vijay Badrinarayanan, Roberto Cipolla, and Alex Kendall. Fiery: Future instance prediction in bird's-eye view from surround monocular cameras. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 15273-15282, 2021. 6 +[5] Junjie Huang and Guan Huang. Bevdet4d: Exploit temporal cues in multi-camera 3d object detection. ArXiv preprint, abs/2203.17054, 2022. 1, 6 +[6] Junjie Huang, Guan Huang, Zheng Zhu, and Dalong Du. Bevdet: High-performance multi-camera 3d object detection in bird-eye-view. ArXiv preprint, abs/2112.11790, 2021. 1, 2, 3, 6 +[7] Alex H. Lang, Sourabh Vora, Holger Caesar, Lubing Zhou, Jiong Yang, and Oscar Beijbom. Pointpillars: Fast encoders for object detection from point clouds. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 12697-12705. Computer Vision Foundation / IEEE, 2019. 2, 3 +[8] Youngwan Lee and Jongyoul Park. Centermask: Real-time anchor-free instance segmentation. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2020, Seattle, WA, USA, June 13-19, 2020, pages 13903-13912. IEEE, 2020. 5, 6, 7 +[9] Yinhao Li, Zheng Ge, Guanyi Yu, Jinrong Yang, Zengran Wang, Yukang Shi, Jianjian Sun, and Zeming Li. Bevdepth: Acquisition of reliable depth for multi-view 3d object detection. ArXiv preprint, abs/2206.10092, 2022. 1, 2, 3, 5, 6, 7 +[10] Zhiqi Li, Wenhai Wang, Hongyang Li, Enze Xie, Chonghao Sima, Tong Lu, Qiao Yu, and Jifeng Dai. BEV-Former: Learning Bird's-Eye-View Representation from Multi-Camera Images via Spatiotemporal Transformers. ArXiv preprint, abs/2203.17270, 2022. 1, 2, 6 +[11] Yingfei Liu, Tiancai Wang, Xiangyu Zhang, and Jian Sun. Petr: Position embedding transformation for multi-view 3d object detection. ArXiv preprint, abs/2203.05625, 2022. 2, 6 + +[12] Zhijian Liu, Haotian Tang, Alexander Amini, Xinyu Yang, Huizi Mao, Daniela Rus, and Song Han. Bevfusion: Multitask multi-sensor fusion with unified bird's-eye view representation. arXiv preprint arXiv:2205.13542, 2022. 1 +[13] Hanspeter A Mallot, Heinrich H Bülthoff, JJ Little, and Stefan Bohrer. Inverse perspective mapping simplifies optical flow computation and obstacle detection. Biological cybernetics, 64(3):177-185, 1991. 1 +[14] NVIDIA, Péter Vingelmann, and Frank H.P. Fitzek. Cuda, release: 10.2.89, 2020. 6 +[15] Bowen Pan, Jiankai Sun, Ho Yin Tiga Leung, Alex Andonian, and Bolei Zhou. Cross-view semantic segmentation for sensing surroundings. IEEE Robotics and Automation Letters, 5(3):4867-4873, 2020. 1 +[16] Dennis Park, Rares Ambrus, Vitor Guizilini, Jie Li, and Adrien Gaidon. Is pseudo-lidar needed for monocular 3d object detection? In IEEE/CVF International Conference on Computer Vision (ICCV), 2021. 5 +[17] Jonah Philion and Sanja Fidler. Lift, splat, shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3d. In European Conference on Computer Vision, pages 194-210. Springer, 2020. 1, 2, 3, 5, 6 +[18] Cody Reading, Ali Harakeh, Julia Chae, and Steven L. Waslander. Categorical depth distribution network for monocular 3d object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 8555-8564, 2021. 1, 2, 8 +[19] Lennart Reiher, Bastian Lampe, and Lutz Eckstein. A sim2real deep learning approach for the transformation of images from multiple vehicle-mounted cameras to a semantically segmented image in bird's eye view. In 2020 IEEE 23rd International Conference on Intelligent Transportation Systems (ITSC), pages 1-7. IEEE, 2020. 1 +[20] Thomas Roddick and Roberto Cipolla. Predicting semantic map representations from images using pyramid occupancy networks. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2020, Seattle, WA, USA, June 13-19, 2020, pages 11135-11144. IEEE, 2020. 1, 2, 4, 8 +[21] Thomas Roddick, Alex Kendall, and Roberto Cipolla. Orthographic feature transform for monocular 3d object detection. In 30th British Machine Vision Conference 2019, BMVC 2019, Cardiff, UK, September 9-12, 2019, page 285. BMVA Press, 2019. 1, 2 +[22] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image computing and computer-assisted intervention, pages 234-241. Springer, 2015. 2, 6 +[23] Daeyun Shin, Zhile Ren, Erik B Sudderth, and Charless C Fowlkes. 3d scene reconstruction with multi-layer depth and epipolar transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2172-2182, 2019. 2 +[24] Siddharth Srivastava, Frederic Jurie, and Gaurav Sharma. Learning 2d to 3d lifting for object detection in 3d for autonomous vehicles. In 2019 IEEE/RSJ International Confer- + +ence on Intelligent Robots and Systems (IROS), pages 4504-4511. IEEE, 2019. 1, 2 +[25] Pei Sun, Henrik Kretzschmar, Xerxes Dotiwalla, Aurelien Chouard, Vijaysai Patnaik, Paul Tsui, James Guo, Yin Zhou, Yuning Chai, Benjamin Caine, Vijay Vasudevan, Wei Han, Jiquan Ngiam, Hang Zhao, Aleksei Timofeev, Scott Ettinger, Maxim Krivokon, Amy Gao, Aditya Joshi, Yu Zhang, Jonathon Shlens, Zhifeng Chen, and Dragomir Anguelov. Scalability in perception for autonomous driving: Waymo open dataset. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), June 2020. 6 +[26] Zhi Tian, Chunhua Shen, Hao Chen, and Tong He. FCOS: fully convolutional one-stage object detection. In 2019 IEEE/CVF International Conference on Computer Vision, ICCV 2019, Seoul, Korea (South), October 27 - November 2, 2019, pages 9626-9635. IEEE, 2019. 2 +[27] Tai Wang, ZHU Xinge, Jiangmiao Pang, and Dahua Lin. Probabilistic and geometric depth: Detecting objects in perspective. In Conference on Robot Learning, pages 1475-1485. PMLR, 2022. 2 +[28] Tai Wang, Xinge Zhu, Jiangmiao Pang, and Dahua Lin. Fcos3d: Fully convolutional one-stage monocular 3d object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 913-922, 2021. 2, 6 +[29] Yan Wang, Wei-Lun Chao, Divyansh Garg, Bharath Hariharan, Mark E. Campbell, and Kilian Q. Weinberger. Pseudolidar from visual depth estimation: Bridging the gap in 3d object detection for autonomous driving. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 8445-8453. Computer Vision Foundation / IEEE, 2019. 3 +[30] Enze Xie, Zhiding Yu, Daquan Zhou, Jonah Philion, Anima Anandkumar, Sanja Fidler, Ping Luo, and Jose M Alvarez. M^2bev: Multi-camera joint 3d detection and segmentation with unified birds-eye view representation. ArXiv preprint, abs/2204.05088, 2022. 1, 6 +[31] Yan Yan, Yuxing Mao, and Bo Li. Second: Sparsely embedded convolutional detection. Sensors, 18(10):3337, 2018. 2, 5 +[32] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Center-based 3d object detection and tracking. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 11784-11793, 2021. 2 +[33] Yin Zhou and Oncel Tuzel. Voxelnet: End-to-end learning for point cloud based 3d object detection. In 2018 IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2018, Salt Lake City, UT, USA, June 18-22, 2018, pages 4490-4499. IEEE Computer Society, 2018. 2, 3 +[34] Benjin Zhu, Zhengkai Jiang, Xiangxin Zhou, Zeming Li, and Gang Yu. Class-balanced grouping and sampling for point cloud 3d object detection. ArXiv preprint, abs/1908.09492, 2019. 5 \ No newline at end of file diff --git a/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/images.zip b/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..f18d8c96a8e96473ec62c0de6098452d1f0564de --- /dev/null +++ b/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:1d4d2b59104659a347ed8af8e6ba40688056911b2809c9cc32ba854fae1eb85b +size 653056 diff --git a/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/layout.json b/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..cc585350f64efff071cf1e48dafa4522b8e2979f --- /dev/null +++ b/2023/MatrixVT_ Efficient Multi-Camera to BEV Transformation for 3D Perception/layout.json @@ -0,0 +1,7457 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 58, + 103, + 536, + 122 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 103, + 536, + 122 + ], + "spans": [ + { + "bbox": [ + 58, + 103, + 536, + 122 + ], + "type": "text", + "content": "MatrixVT: Efficient Multi-Camera to BEV Transformation for 3D Perception" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 165, + 143, + 431, + 172 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 165, + 143, + 431, + 172 + ], + "spans": [ + { + "bbox": [ + 165, + 143, + 431, + 172 + ], + "type": "text", + "content": "Hongyu Zhou, Zheng Ge, Zeming Li, Xiangyu Zhang* MEGVII Technology" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 145, + 174, + 448, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 145, + 174, + 448, + 185 + ], + "spans": [ + { + "bbox": [ + 145, + 174, + 448, + 185 + ], + "type": "text", + "content": "{zhouhongyu, gezheng, lizeming, zhangxiangyu}@megvii.com" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "spans": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 238, + 290, + 478 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 238, + 290, + 478 + ], + "spans": [ + { + "bbox": [ + 46, + 238, + 290, + 478 + ], + "type": "text", + "content": "This paper proposes an efficient multi-camera to Bird's-Eye-View (BEV) view transformation method for 3D perception, dubbed MatrixVT. Existing view transformers either suffer from poor efficiency or rely on device-specific operators, hindering the broad application of BEV models. In contrast, our method generates BEV features efficiently with only convolutions and matrix multiplications (MatMul). Specifically, we propose describing the BEV feature as the MatMul of image feature and a sparse Feature Transporting Matrix (FTM). A Prime Extraction module is then introduced to compress the dimension of image features and reduce FTM's sparsity. Moreover, we propose the Ring & Ray Decomposition to replace the FTM with two matrices and reformulate our pipeline to reduce calculation further. Compared to existing methods, MatrixVT enjoys a faster speed and less memory footprint while remaining deploy-friendly. Extensive experiments on nuScenes and Waymo benchmarks demonstrate that our method is highly efficient but obtains results on par with the SOTA method in object detection and map segmentation tasks." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 500, + 128, + 513 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 500, + 128, + 513 + ], + "spans": [ + { + "bbox": [ + 47, + 500, + 128, + 513 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 520, + 287, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 520, + 287, + 616 + ], + "spans": [ + { + "bbox": [ + 46, + 520, + 287, + 616 + ], + "type": "text", + "content": "Vision-centric 3D perception in Bird's-Eye-View (BEV) [17, 20, 24] has recently drawn extensive attention. Apart from their outstanding performance, the compact and unified feature representation in BEV facilitates straight-forward feature fusions [1, 5, 12, 10], and enables various downstream tasks (e.g. object detection [6, 9, 10], map segmentation [17, 30], motion planning, etc.) to be applied thereon easily." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 616, + 288, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 616, + 288, + 677 + ], + "spans": [ + { + "bbox": [ + 46, + 616, + 288, + 677 + ], + "type": "text", + "content": "View Transformation (VT) is the key component that converts multi-camera features to BEV, which has been heavily studied in previous works [15, 20, 17, 24, 10, 6, 21, 9]. Existing VT methods can be categorized into geometry-based [13, 19, 17, 9, 18, 30] and learning-based meth" + } + ] + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 319, + 212, + 533, + 295 + ], + "blocks": [ + { + "bbox": [ + 319, + 212, + 533, + 295 + ], + "lines": [ + { + "bbox": [ + 319, + 212, + 533, + 295 + ], + "spans": [ + { + "bbox": [ + 319, + 212, + 533, + 295 + ], + "type": "image", + "image_path": "fb432dea189edc91f47fda152fc823b97f4dc9a705573a076f8533d24976038c.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 320, + 297, + 533, + 379 + ], + "blocks": [ + { + "bbox": [ + 320, + 297, + 533, + 379 + ], + "lines": [ + { + "bbox": [ + 320, + 297, + 533, + 379 + ], + "spans": [ + { + "bbox": [ + 320, + 297, + 533, + 379 + ], + "type": "image", + "image_path": "2ae6134179487d9f3d9d7dd0f488ca92d55bf898131976f820bc1c245eec3d8e.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 381, + 547, + 426 + ], + "lines": [ + { + "bbox": [ + 305, + 381, + 547, + 426 + ], + "spans": [ + { + "bbox": [ + 305, + 381, + 547, + 426 + ], + "type": "text", + "content": "Figure 1. The pipeline of Lift-Splat (upper) and our proposed MatrixVT (lower). We compress image features before VT to reduce memory footprint and calculation. Note that only standard operators are adopted in MatrixVT." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 449, + 547, + 592 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 449, + 547, + 592 + ], + "spans": [ + { + "bbox": [ + 304, + 449, + 547, + 592 + ], + "type": "text", + "content": "ods [10, 20, 15]. Among these two categories, geometry-based methods show superior performance due to the use of geometric constraints. Lift-Splat [17], as a representative geometry-based VT, predicts categorical depth distribution for each pixel and \"lift\" the corresponding features into 3D space according to the predicted depth. These feature vectors are then gathered into pre-defined grids on a reference BEV plane (i.e., \"splat\") to form the BEV feature (Fig. 1, upper). The Lift-Splat-based VT has shown great potential to produce high-quality BEV features, achieving remarkable performance on object detection [9, 5] and map segmentation tasks." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 594, + 548, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 548, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 548, + 715 + ], + "type": "text", + "content": "Despite the effectiveness of Lift-Splat-like VT [9], two issues remain. First, the \"splat\" operation is not universally feasible. Existing implementations of \"splat\" relies on either the \"cumsum trick\" [17, 6] that is highly inefficient, or customized operators [9] that can only be used on specific devices, making application of BEV perception methods costly. Second, the size of \"lifted\" multi-view image features is huge, becoming the memory bottleneck of BEV models. These two issues lead to a heavy burden on BEV methods during both the training and inference phases. As" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 683, + 288, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 683, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 683, + 288, + 713 + ], + "type": "text", + "content": "*Corresponding author. This research was supported by National Key R&D Program of China (No. 2017YFA0700800) and Beijing Academy of Artificial Intelligence (BAAI)." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8548" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 95 + ], + "type": "text", + "content": "a result, the drawbacks of existing view transformers limit the broad application of autonomous driving technology" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 96, + 286, + 191 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 96, + 286, + 191 + ], + "spans": [ + { + "bbox": [ + 46, + 96, + 286, + 191 + ], + "type": "text", + "content": "In this work, we propose a novel VT method to address the above problems. MatrixVT is proposed based on the fact that the VT can be viewed as a feature transportation process. In that case, the BEV feature can be viewed as the MatMul between the \"lifted\" feature and a transporting matrix, namely Feature Transporting Matrix (FTM). We thus generalize the Lift-Splat VT into a simple form and eliminate specialized operators." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 192, + 286, + 430 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 192, + 286, + 430 + ], + "spans": [ + { + "bbox": [ + 46, + 192, + 286, + 430 + ], + "type": "text", + "content": "However, transformation with FTM is a kind of degradation — the mapping between the 3D space and BEV grids is extreme sparse, leading to the huge size of FTM and poor efficiency. Prior works [9, 18] seek customized operators, successfully avoiding such sparsity. In this paper, we argue that there are other solutions to the problem of sparse mapping. First, we propose Prime Extraction. Motivated by an observation that the height (vertical) dimension of images is less informative in autonomous driving (see Sec. 3.2), we compress the image features along this dimension before VT. Second, we adopt matrix decomposition to reduce the sparsity of FTM. The proposed Ring & Ray Decomposition orthogonally decomposes the FTM into two separate matrices, each encoding the distance and direction of the ego-centric polar coordinate. This decomposition also allows us to reformulate our pipeline into a mathematically equivalent but more efficient one (Fig. 1, lower). These two techniques reduce memory footprint and calculation during VT by hundreds of times, enabling MatrixVT to be more efficient than existing methods." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 431, + 286, + 561 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 431, + 286, + 561 + ], + "spans": [ + { + "bbox": [ + 46, + 431, + 286, + 561 + ], + "type": "text", + "content": "The proposed MatrixVT inherits the advantages of the Lift-Splat [17] paradigm while being much more memory efficient and fast. Extensive experimental results show that MatrixVT is 2-to-8 times faster than previous methods [9, 6] and saves up to " + }, + { + "bbox": [ + 46, + 431, + 286, + 561 + ], + "type": "inline_equation", + "content": "97\\%" + }, + { + "bbox": [ + 46, + 431, + 286, + 561 + ], + "type": "text", + "content": " memory footprint among different settings. Meanwhile, the perception model with MatrixVT achieves " + }, + { + "bbox": [ + 46, + 431, + 286, + 561 + ], + "type": "inline_equation", + "content": "46.6\\%" + }, + { + "bbox": [ + 46, + 431, + 286, + 561 + ], + "type": "text", + "content": " mAP and " + }, + { + "bbox": [ + 46, + 431, + 286, + 561 + ], + "type": "inline_equation", + "content": "56.2\\%" + }, + { + "bbox": [ + 46, + 431, + 286, + 561 + ], + "type": "text", + "content": " NDS for object detection and " + }, + { + "bbox": [ + 46, + 431, + 286, + 561 + ], + "type": "inline_equation", + "content": "46.2\\%" + }, + { + "bbox": [ + 46, + 431, + 286, + 561 + ], + "type": "text", + "content": " mIoU for vehicle segmentation on the nuScenes [2] val set, which is comparable to the state-of-the-art performance [9]. We conclude our main contributions as follows:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 58, + 568, + 286, + 713 + ], + "type": "list", + "angle": 0, + "index": 7, + "blocks": [ + { + "bbox": [ + 58, + 568, + 286, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 568, + 286, + 604 + ], + "spans": [ + { + "bbox": [ + 58, + 568, + 286, + 604 + ], + "type": "text", + "content": "- We propose a new description of multi-camera to BEV transformation — using the Feature Transportation Matrix (FTM), which is a more general representation." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 58, + 611, + 286, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 611, + 286, + 647 + ], + "spans": [ + { + "bbox": [ + 58, + 611, + 286, + 647 + ], + "type": "text", + "content": "- To solve the sparse mapping problem, we propose Prime Extraction and the Ring & Ray Decomposition, boosting VT with FTM by a huge margin." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 58, + 653, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 653, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 58, + 653, + 286, + 713 + ], + "type": "text", + "content": "- Extensive experiments demonstrate that MatrixVT yields comparable performance to the state-of-the-art method on the nuScenes object detection and map segmentation tasks while being more efficient and generally applicable." + } + ] + } + ], + "index": 6 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 71, + 397, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 71, + 397, + 83 + ], + "spans": [ + { + "bbox": [ + 306, + 71, + 397, + 83 + ], + "type": "text", + "content": "2. Related Works" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 91, + 427, + 104 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 91, + 427, + 104 + ], + "spans": [ + { + "bbox": [ + 306, + 91, + 427, + 104 + ], + "type": "text", + "content": "2.1. Visual 3D Perception" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 110, + 545, + 182 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 110, + 545, + 182 + ], + "spans": [ + { + "bbox": [ + 304, + 110, + 545, + 182 + ], + "type": "text", + "content": "Camera-based perception [28, 27, 6, 10, 11] is the most commonly used method for various scenarios due to its low cost and high accessibility. Comparing with 2D perception (object detection [26], semantic segmentation [22], etc.), 3D perception requires additional prediction of the depth information which is a naturally ill-posed problem [21]." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 182, + 545, + 433 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 182, + 545, + 433 + ], + "spans": [ + { + "bbox": [ + 304, + 182, + 545, + 433 + ], + "type": "text", + "content": "Existing works either predict the depth information explicitly or implicitly. FCOS3D [28] simply extends the structure of the classic 2D object detector [26], predicting pixel-wise depth explicitly using an extra sub-net. CaDDN [18] proposes treating depth prediction as a classification task rather than a regression task, and projecting image feature into Bird's-Eye-View (BEV) space to achieve unified modeling of detection and depth prediction. BEVDepth [9] proposes a heavy and well-designed subnet for depth prediction, achieving outstanding performance among other 3D object detectors. Meanwhile, methods like PON [20], BirdGAN [24], and EFT [23] use fully learnable networks to implement feature transformation, learning object depth implicitly using segmentation or detection supervision. Among theme, EFT [23] proposes using a learnable matrix for VT, which bears some resemblance, in form, to the Feature Transformation Matrix (FTM) we proposed. However, the matrices we designed for MatrixVT contains clear physical meanings with explicit depth modeling, and there are significant differences in their applicable scenarios and methods of use." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 443, + 470, + 455 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 443, + 470, + 455 + ], + "spans": [ + { + "bbox": [ + 306, + 443, + 470, + 455 + ], + "type": "text", + "content": "2.2. Perception in Bird's-Eye-View" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 461, + 545, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 461, + 545, + 628 + ], + "spans": [ + { + "bbox": [ + 304, + 461, + 545, + 628 + ], + "type": "text", + "content": "The concept of BEV is firstly proposed for processing LiDAR point cloud [33, 7, 31, 32], and found effective for fusing multi-view image features. The core component of vision-based BEV paradigm is the view-transformation. OFT [21] firstly propose mapping image feature from Perspective View into BEV using camera parameters. This method projects a reference point from a BEV grid to the image plane, and sample corresponding features back to the BEV grid. Following this work, BEVFormer [10] proposes using Attention module to sample features around the reference point. These methods fail to distinguish BEV grids that are projected to the same position on the image plane, thus showing inferior performance than depth-based methods." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "text", + "content": "Depth-based methods, represented by LSS [17] and CaDDN [18], predict categorical depth for each pixel, the extracted image feature on a specific pixel is then projected into 3D space by doing per-pixel outer product with corresponding depth. The projected high-dimensional tensor is then \"collapsed\" to a BEV reference plane using convolution [18], Pillar Pooling [17, 6], or Voxel Pooling [9]. Lift-" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8549" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": "Splat based methods [17, 9, 6] show outstanding performance for downstream tasks but introduce two extra problems. Firstly, the intermediate representation of image features is large and in-efficient, making training and application of these methods difficult. Secondly, the Pillar Pooling [17] introduces random memory access, which is slow and device-demanding (extremely slow on general-purpose devices). In this paper, we propose a new depth-based view transformation to overcome these problems while retaining the ability to produce high-quality BEV features." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 203, + 116, + 216 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 203, + 116, + 216 + ], + "spans": [ + { + "bbox": [ + 47, + 203, + 116, + 216 + ], + "type": "text", + "content": "3. MatrixVT" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 223, + 287, + 342 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 223, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 46, + 223, + 287, + 342 + ], + "type": "text", + "content": "The MatrixVT is a simple view transformer based on the depth-based VT paradigm. In Sec. 3.1, we first revisit existing Lift-Splat transformation [17, 9] and introduce the concept of Feature Transporting Matrix (FTM) together with the sparse mapping problem. Then, techniques proposed to solve the problem of sparse mapping i.e., Prime Extraction (Sec. 3.2) and Ring & Ray Decomposition (Sec. 3.3), are introduced. In Sec. 3.4, we designate the novel VT method utilizing the aforementioned techniques as MatrixVT, and elaborate its overall pipeline." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "spans": [ + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "text", + "content": "For clarity, we use letters of the normal script " + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "inline_equation", + "content": "(e.g. F)" + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "text", + "content": " for tensors, the Roman script for matrices " + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "inline_equation", + "content": "(e.g. M)" + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "text", + "content": ", and Bold script " + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "inline_equation", + "content": "(e.g. v)" + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "text", + "content": " for vectors. Besides, " + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "inline_equation", + "content": "A \\cdot B" + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "text", + "content": " denotes Matrix Multiplication (MatMul), " + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "inline_equation", + "content": "A \\odot B" + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "text", + "content": " denotes Hadamard Product, and " + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "inline_equation", + "content": "a \\otimes b" + }, + { + "bbox": [ + 46, + 342, + 288, + 403 + ], + "type": "text", + "content": " denotes outer product." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 411, + 128, + 423 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 411, + 128, + 423 + ], + "spans": [ + { + "bbox": [ + 47, + 411, + 128, + 423 + ], + "type": "text", + "content": "3.1. Background" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "spans": [ + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": "Lift-Splat-like methods exploit the idea of pseudo-LiDAR [29] and LiDAR-based BEV methods [33, 7] for View Transformation. Image features are \"lifted\" to 3D space and processed like point cloud. We define " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "N_{c}" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": " as the number of cameras for a specific scene; " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "N_{d}" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": " as the number of depth bins; " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "H_{I}" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "W_{I}" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": " to be the height and width of image features; " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "H_{B}" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "W_{B}" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": " to be the height and width of BEV features (i.e., shape of BEV grids); " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": " to be the number of feature channels. Consequently, let multi-view image features to be " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "F \\in \\mathbb{R}^{N_c \\times H_I \\times W_I \\times C}" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": "; categorical depth to be " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "D \\in \\mathbb{R}^{N_c \\times H_I \\times W_I \\times N_d}" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": "; BEV features to be " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "F_{BEV} \\in \\mathbb{R}^{H_B \\times W_B \\times C}" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": " (initialized to zeros). The Lift-Splat VT first \"lift\" the " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": " into 3D space by doing per-pixel outer product with " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": ", obtaining the high-dimensional intermediate tensor " + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "inline_equation", + "content": "F_{inter} \\in \\mathbb{R}^{N_c \\times H_I \\times W_I \\times N_d \\times C}" + }, + { + "bbox": [ + 46, + 430, + 289, + 610 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 52, + 617, + 287, + 633 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 617, + 287, + 633 + ], + "spans": [ + { + "bbox": [ + 52, + 617, + 287, + 633 + ], + "type": "interline_equation", + "content": "F _ {i n t e r} = \\left\\{F _ {i n t e r} ^ {h, w} \\right\\} _ {H _ {I}, W _ {I}} = \\left\\{\\boldsymbol {F} ^ {h, w} \\cdot \\left(\\boldsymbol {D} ^ {h, w}\\right) ^ {T} \\right\\} _ {H _ {I}, W _ {I}} (1)", + "image_path": "ad0d974eec3d672696ce30a64301d9999682b446ea0568043dd3ea0d1f30c42d.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 641, + 288, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 288, + 712 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 288, + 712 + ], + "type": "text", + "content": "The intermediate tensor can be treated as " + }, + { + "bbox": [ + 46, + 641, + 288, + 712 + ], + "type": "inline_equation", + "content": "N_{c} \\times H_{I} \\times W_{I} \\times N_{d}" + }, + { + "bbox": [ + 46, + 641, + 288, + 712 + ], + "type": "text", + "content": " feature vectors, each vector corresponding to a geometric coordinate. The \"splat\" operation is then adopted using operators like Pillar Pooling [17], during which each feature vector is summed to a BEV grid according to geometric coordinates." + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 320, + 77, + 538, + 279 + ], + "blocks": [ + { + "bbox": [ + 320, + 77, + 538, + 279 + ], + "lines": [ + { + "bbox": [ + 320, + 77, + 538, + 279 + ], + "spans": [ + { + "bbox": [ + 320, + 77, + 538, + 279 + ], + "type": "image", + "image_path": "c35f78c0a1284a07e5b1b47e5e22fea5f606d0fa6d018ed8705abde2f0b82639.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 281, + 545, + 315 + ], + "lines": [ + { + "bbox": [ + 305, + 281, + 545, + 315 + ], + "spans": [ + { + "bbox": [ + 305, + 281, + 545, + 315 + ], + "type": "text", + "content": "Figure 2. Response strengths along vertical and horizontal dimensions. For autonomous driving, the variance of response on the width dimension is higher than height dimension." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 334, + 545, + 430 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 334, + 545, + 430 + ], + "spans": [ + { + "bbox": [ + 305, + 334, + 545, + 430 + ], + "type": "text", + "content": "We find that the \"splat\" operation is a fixed mapping between the intermediate tensor and BEV grids. Therefore, we use a Feature Transporting Matrix " + }, + { + "bbox": [ + 305, + 334, + 545, + 430 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_{\\mathrm{FT}} \\in \\mathbb{R}^{(H_B \\times W_B) \\times (N_c \\times H_I \\times W_I \\times N_d)}" + }, + { + "bbox": [ + 305, + 334, + 545, + 430 + ], + "type": "text", + "content": " to describe this mapping. The FTM can be strictly equal to Pillar Pooling in LSS [17] or encodes different sampling rules (i.e., Gaussian sampling). The FTM enables feature transportation with Matrix Multiplication (MatMul):" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 380, + 439, + 545, + 452 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 380, + 439, + 545, + 452 + ], + "spans": [ + { + "bbox": [ + 380, + 439, + 545, + 452 + ], + "type": "interline_equation", + "content": "\\mathrm {F} _ {\\text {B E V}} = \\mathrm {M} _ {\\mathrm {F T}} \\cdot \\mathrm {F} _ {\\text {i n t e r}} \\tag {2}", + "image_path": "d1aea3d5d7a74609f42730d8fe6b95aa404be6d5e8d849002f25e25496334ba0.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 459, + 545, + 496 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 459, + 545, + 496 + ], + "spans": [ + { + "bbox": [ + 305, + 459, + 545, + 496 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 459, + 545, + 496 + ], + "type": "inline_equation", + "content": "\\mathrm{F}_{\\mathrm{inter}}\\in \\mathbb{R}^{(N_c\\times H_I\\times W_I\\times N_d)\\times C}" + }, + { + "bbox": [ + 305, + 459, + 545, + 496 + ], + "type": "text", + "content": " is the \"lifted\" feature " + }, + { + "bbox": [ + 305, + 459, + 545, + 496 + ], + "type": "inline_equation", + "content": "F_{inter}" + }, + { + "bbox": [ + 305, + 459, + 545, + 496 + ], + "type": "text", + "content": " in matrix format, " + }, + { + "bbox": [ + 305, + 459, + 545, + 496 + ], + "type": "inline_equation", + "content": "\\mathrm{F_{BEV}}\\in \\mathbb{R}^{(H_B\\times W_B)\\times C}" + }, + { + "bbox": [ + 305, + 459, + 545, + 496 + ], + "type": "text", + "content": " is the BEV feature " + }, + { + "bbox": [ + 305, + 459, + 545, + 496 + ], + "type": "inline_equation", + "content": "F_{BEV}" + }, + { + "bbox": [ + 305, + 459, + 545, + 496 + ], + "type": "text", + "content": " in matrix format." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 497, + 545, + 591 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 497, + 545, + 591 + ], + "spans": [ + { + "bbox": [ + 304, + 497, + 545, + 591 + ], + "type": "text", + "content": "Replacing the \"splat\" operation with FTM eliminates the need for customized operators. However, the sparse mapping between the 3D space and BEV grids can lead to a massive and highly sparse FTM, which harms the efficiency of matrix-based VT. To address the sparse mapping problem without customized operators, we propose two techniques to reduce the sparsity of FTM and speed up the transformation." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 599, + 527, + 612 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 599, + 527, + 612 + ], + "spans": [ + { + "bbox": [ + 306, + 599, + 527, + 612 + ], + "type": "text", + "content": "3.2. Prime Extraction for Autonomous Driving" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": "The high-dimensional intermediate tensor is the primary cause of the sparse mapping and the low efficiency of Lift-Splat-like VT. An intuitive way to reduce sparsity is reducing the size of " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "F_{inter}" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": ". In the context of autonomous driving, a notable observation can lead to feature compression. As can be seen in Fig. 2, the height dimension of camera images contains less informative data. The height dimension is filled with redundant and background features, making it" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "8550" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 72, + 276, + 292 + ], + "blocks": [ + { + "bbox": [ + 53, + 72, + 276, + 292 + ], + "lines": [ + { + "bbox": [ + 53, + 72, + 276, + 292 + ], + "spans": [ + { + "bbox": [ + 53, + 72, + 276, + 292 + ], + "type": "image", + "image_path": "97bfd8c3e8fb7a389411074bad6122cdc7fea34b1433ce6a165d97782774cf53.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 295, + 289, + 340 + ], + "lines": [ + { + "bbox": [ + 46, + 295, + 289, + 340 + ], + "spans": [ + { + "bbox": [ + 46, + 295, + 289, + 340 + ], + "type": "text", + "content": "Figure 3. The Prime Extraction module. The categorical depth is reduced guided by Prime Depth Attention, while the image feature is reduced by Prime Feature Extractor (PFE), which consists of MaxPooling and convolutions for refinement." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 361, + 287, + 409 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 361, + 287, + 409 + ], + "spans": [ + { + "bbox": [ + 46, + 361, + 287, + 409 + ], + "type": "text", + "content": "ideal for feature compression. Therefore, we propose Prime Extraction, which is a compression technique that can be used in autonomous driving and other scenarios with information redundancy of this nature." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 411, + 287, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 411, + 287, + 567 + ], + "spans": [ + { + "bbox": [ + 46, + 411, + 287, + 567 + ], + "type": "text", + "content": "As shown in Fig. 3, the Prime Extraction module predicts Prime Depth Attention for each direction (a column of the tensor) guided by the image feature. It generates the Prime Depth as a weighted sum of categorical depth distributions. Meanwhile, the Prime Feature is obtained by the Prime Feature Extractor (PFE), which consists of position embedding, column-wise max-pooling, and convolutions for refinement. By applying Prime Extraction to matrix-based VT, we successfully reduce the FTM to " + }, + { + "bbox": [ + 46, + 411, + 287, + 567 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_{\\mathrm{FT}}^{\\prime} \\in \\mathbb{R}^{(H_B \\times W_B) \\times (N_c \\times W_I \\times N_d)}" + }, + { + "bbox": [ + 46, + 411, + 287, + 567 + ], + "type": "text", + "content": ", which is " + }, + { + "bbox": [ + 46, + 411, + 287, + 567 + ], + "type": "inline_equation", + "content": "H_{I}" + }, + { + "bbox": [ + 46, + 411, + 287, + 567 + ], + "type": "text", + "content": " times smaller than the raw matrix. The pipeline of generating the BEV feature using the Prime Feature and the Prime Depth is demonstrated in Fig. 4 (yellow box)." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 568, + 287, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 568, + 287, + 676 + ], + "spans": [ + { + "bbox": [ + 46, + 568, + 287, + 676 + ], + "type": "text", + "content": "The prime extraction is motivated by an observation: The image feature's height dimension has a lower response variance than the width dimension. This observation indicates that this dimension contains less information than the width dimension. We thus propose to compress image features on the height dimension. Previous works have also exploited reducing the height dimension of image features [20, 1], but we firstly propose compressing both image features and corresponding depth to boost VT." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 677, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 288, + 713 + ], + "type": "text", + "content": "In Sec. 4.4, we will show that the extracted Prime Feature and Prime Depth effectively retain valuable information from the raw feature and produce BEV features of the" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 72, + 546, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 546, + 120 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 546, + 120 + ], + "type": "text", + "content": "same high quality as the raw feature. Moreover, the Prime Extraction technique can be individually adapted to existing Lift-Splat-like VTs to enhance their efficiency at almost no performance cost." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 128, + 477, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 128, + 477, + 140 + ], + "spans": [ + { + "bbox": [ + 305, + 128, + 477, + 140 + ], + "type": "text", + "content": "3.3. \"Ring and Ray\" Decomposition" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "spans": [ + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": "The sparsity of FTM can be further reduced by matrix decomposition. To this end, we propose the \"Ring & Ray\" Decomposition. Without loss of generality, we can set the " + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "inline_equation", + "content": "N_{c}" + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": " to 1 and view " + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_{\\mathrm{FT}}^{\\prime}" + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": " as a tensor " + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "inline_equation", + "content": "M_{FT}^{\\prime}" + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": ". In that case, the shape of " + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "inline_equation", + "content": "M_{FT}^{\\prime}" + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": " would be " + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "inline_equation", + "content": "H_{B} \\times W_{B} \\times W_{I} \\times N_{d}" + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": ". We note that its dimension of size " + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "inline_equation", + "content": "W_{I}" + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": " can be viewed as the direction in a polar coordinate, since each column of the image feature represents information of a specific direction. Likewise, the dimension of size " + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "inline_equation", + "content": "N_{d}" + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": " can be viewed as the distance in the polar coordinate. In other words, the image feature required for a specific BEV grid can be located by direction and distance. We thus propose to orthogonally decompose the " + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "inline_equation", + "content": "M_{FT}^{\\prime}" + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": " into two separate matrices, each encoding the directional or distance information. Specifically, we use a Ring Matrix " + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_{\\mathrm{Ring}} \\in \\mathbb{R}^{N_d \\times (H_B \\times W_B)}" + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": " to encode distance information and a Ray Matrix " + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_{\\mathrm{Ray}} \\in \\mathbb{R}^{W_I \\times (H_B \\times W_B)}" + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": " to encode directional information (see Appendix 1.1 for pseudo code). The Ring & Ray Decomposition effectively reduces the size of static parameters. The number of predefined parameters (size of FTM) is reduced from " + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "inline_equation", + "content": "W_{I} \\times N_{d} \\times H_{B} \\times W_{B}" + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "inline_equation", + "content": "(W_{I} + N_{d}) \\times H_{B} \\times W_{B}" + }, + { + "bbox": [ + 304, + 146, + 546, + 410 + ], + "type": "text", + "content": ", which is typically 30 to 50 times less1." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 410, + 545, + 458 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 410, + 545, + 458 + ], + "spans": [ + { + "bbox": [ + 304, + 410, + 545, + 458 + ], + "type": "text", + "content": "Then we show how to use these two matrices for VT. Given the Prime Feature and Prime Depth, we first do the per-pixel outer product of them as in Lift-Splat to obtain the \"lifted feature\" " + }, + { + "bbox": [ + 304, + 410, + 545, + 458 + ], + "type": "inline_equation", + "content": "F_{inter} \\in \\mathbb{R}^{W_I \\times N_d \\times C}" + }, + { + "bbox": [ + 304, + 410, + 545, + 458 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 333, + 467, + 545, + 482 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 333, + 467, + 545, + 482 + ], + "spans": [ + { + "bbox": [ + 333, + 467, + 545, + 482 + ], + "type": "interline_equation", + "content": "F _ {i n t e r} = \\left\\{F _ {i n t e r} ^ {w} \\right\\} _ {W _ {I}} = \\left\\{\\boldsymbol {F} ^ {\\boldsymbol {w}} \\otimes \\left(\\boldsymbol {D} ^ {\\boldsymbol {w}}\\right) ^ {T} \\right\\} _ {W _ {I}} \\tag {3}", + "image_path": "391e17cc0eabd4678e87ec424d9fa1d15c812fab93232329cdbf6ef315cc19e0.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "spans": [ + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "type": "text", + "content": "Then, as illustrated in Fig. 4, instead of using " + }, + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "type": "inline_equation", + "content": "\\mathrm{M}_{\\mathrm{FT}}'" + }, + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "type": "text", + "content": " to directly transform it into a BEV feature (yellow box), we transpose " + }, + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "type": "inline_equation", + "content": "F_{inter}" + }, + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "type": "text", + "content": ", view it as a matrix " + }, + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "type": "inline_equation", + "content": "\\mathrm{F}_{\\mathrm{inter}} \\in \\mathbb{R}^{N_d \\times (W_I \\times C)}" + }, + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "type": "text", + "content": ", and do MatMul between the Ring Matrix and " + }, + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "type": "inline_equation", + "content": "\\mathrm{F}_{\\mathrm{inter}}" + }, + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "type": "text", + "content": " to obtain an intermediate feature. The intermediate feature is then masked by doing a Hadamard Product with the Ray Matrix, summed on the dimension of " + }, + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "type": "inline_equation", + "content": "W_I" + }, + { + "bbox": [ + 304, + 490, + 545, + 586 + ], + "type": "text", + "content": " to obtain the BEV feature. (Fig. 4, blue box, summation omitted)." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 355, + 596, + 545, + 609 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 355, + 596, + 545, + 609 + ], + "spans": [ + { + "bbox": [ + 355, + 596, + 545, + 609 + ], + "type": "interline_equation", + "content": "\\mathrm {F} _ {\\text {i n t e r}} ^ {*} = \\mathrm {M} _ {\\text {R a y}} \\odot (\\mathrm {M} _ {\\text {R i n g}} \\cdot \\mathrm {F} _ {\\text {i n t e r}}) \\tag {4}", + "image_path": "f2a802314024ad054a4778a9cf4a06014bb8b0f1b36bfc2c61402a464db941a3.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 384, + 612, + 545, + 635 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 384, + 612, + 545, + 635 + ], + "spans": [ + { + "bbox": [ + 384, + 612, + 545, + 635 + ], + "type": "interline_equation", + "content": "F _ {B E V} = \\sum_ {w} F _ {\\text {i n t e r}} ^ {* w} \\tag {5}", + "image_path": "4495c0b0530a3ae4fa6aba398852823589e67fea2213f1bae0198beaa812e016.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 645, + 539, + 659 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 645, + 539, + 659 + ], + "spans": [ + { + "bbox": [ + 304, + 645, + 539, + 659 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 645, + 539, + 659 + ], + "type": "inline_equation", + "content": "F_{inter}^{*}\\in \\mathbb{R}^{W_I\\times C\\times H_B\\times W_B}" + }, + { + "bbox": [ + 304, + 645, + 539, + 659 + ], + "type": "text", + "content": " is " + }, + { + "bbox": [ + 304, + 645, + 539, + 659 + ], + "type": "inline_equation", + "content": "\\mathrm{F}_{\\mathrm{inter}}^{*}" + }, + { + "bbox": [ + 304, + 645, + 539, + 659 + ], + "type": "text", + "content": " in tensor form." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 659, + 545, + 694 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 659, + 545, + 694 + ], + "spans": [ + { + "bbox": [ + 304, + 659, + 545, + 694 + ], + "type": "text", + "content": "However, this decomposition do not reduce the FLOPs during VT and introduces the Intermediate Feature in Fig. 4 (blue) whose size if huge and depends on feature channel" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 315, + 702, + 490, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 702, + 490, + 712 + ], + "spans": [ + { + "bbox": [ + 315, + 702, + 490, + 712 + ], + "type": "text", + "content": "Under feature width 44 and 88, with 112 depth bins." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 294, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 314, + 757 + ], + "type": "text", + "content": "8551" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 88, + 545, + 265 + ], + "blocks": [ + { + "bbox": [ + 53, + 75, + 263, + 87 + ], + "lines": [ + { + "bbox": [ + 53, + 75, + 263, + 87 + ], + "spans": [ + { + "bbox": [ + 53, + 75, + 263, + 87 + ], + "type": "text", + "content": "Pipelines of View Transformation Using Matrices" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 53, + 88, + 545, + 265 + ], + "lines": [ + { + "bbox": [ + 53, + 88, + 545, + 265 + ], + "spans": [ + { + "bbox": [ + 53, + 88, + 545, + 265 + ], + "type": "image", + "image_path": "5649bb5366d44480f42c3ea588f88dd7b376088d50546afcc108adc67a7bacb3.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 267, + 547, + 312 + ], + "lines": [ + { + "bbox": [ + 46, + 267, + 547, + 312 + ], + "spans": [ + { + "bbox": [ + 46, + 267, + 547, + 312 + ], + "type": "text", + "content": "Figure 4. View Transformation using matrices. We first extract features from the image and predict categorical depth for each pixel. The obtained feature and depth are sent to the Prime Extraction module for compression. With the compressed Prime Feature and the Prime Depth, we \"lift\" the 1D Prime Feature into 2D space using Prime Depth. The \"lifted feature\" is then transformed into the BEV feature by MatMul with FTM or the decomposed Ring & Ray matrices." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 331, + 287, + 368 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 331, + 287, + 368 + ], + "spans": [ + { + "bbox": [ + 47, + 331, + 287, + 368 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 47, + 331, + 287, + 368 + ], + "type": "text", + "content": ". To reduce the calculation and memory footprint during VT, we combine Eq. 3 to Eq. 5 and rewrite them in a mathematically equivalent form (see Appendix 1.2 for proof):" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 93, + 375, + 287, + 389 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 93, + 375, + 287, + 389 + ], + "spans": [ + { + "bbox": [ + 93, + 375, + 287, + 389 + ], + "type": "interline_equation", + "content": "\\mathrm {F} _ {\\mathrm {B E V}} = \\mathrm {F} \\cdot \\left(\\mathrm {M} _ {\\text {R a y}} \\odot \\left(\\mathrm {M} _ {\\text {R i n g}} \\cdot \\mathrm {D}\\right)\\right) \\tag {6}", + "image_path": "46ca3a929c7a7991817a3fc4398072481f56b816862062d16219819587f59047.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 396, + 287, + 456 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 396, + 287, + 456 + ], + "spans": [ + { + "bbox": [ + 47, + 396, + 287, + 456 + ], + "type": "text", + "content": "With this reformulation, we reduce the calculation during VT from " + }, + { + "bbox": [ + 47, + 396, + 287, + 456 + ], + "type": "inline_equation", + "content": "2 \\times W_{I} \\times C \\times N_{d} \\times H_{B} \\times W_{B}" + }, + { + "bbox": [ + 47, + 396, + 287, + 456 + ], + "type": "text", + "content": " FLOPs to " + }, + { + "bbox": [ + 47, + 396, + 287, + 456 + ], + "type": "inline_equation", + "content": "2(C + N_{d} + 1) \\times W_{I} \\times H_{B} \\times W_{B}" + }, + { + "bbox": [ + 47, + 396, + 287, + 456 + ], + "type": "text", + "content": " FLOPs; the memory footprint is also reduced from " + }, + { + "bbox": [ + 47, + 396, + 287, + 456 + ], + "type": "inline_equation", + "content": "W_{I} \\times N_{d} \\times H_{B} \\times W_{B}" + }, + { + "bbox": [ + 47, + 396, + 287, + 456 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 47, + 396, + 287, + 456 + ], + "type": "inline_equation", + "content": "(W_{I} + N_{d}) \\times H_{B} \\times W_{B}" + }, + { + "bbox": [ + 47, + 396, + 287, + 456 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 463, + 146, + 475 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 463, + 146, + 475 + ], + "spans": [ + { + "bbox": [ + 47, + 463, + 146, + 475 + ], + "type": "text", + "content": "3.4. Overall Pipeline" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 481, + 287, + 540 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 481, + 287, + 540 + ], + "spans": [ + { + "bbox": [ + 46, + 481, + 287, + 540 + ], + "type": "text", + "content": "With above techniques, we reduce the calculation and memory footprint using FTM by hundreds of times, making VT with FTM not only feasible but also efficient. Given the multi-view images for a specific scene, we conclude the overall pipeline of MatrixVT as follows:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 54, + 548, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 55, + 548, + 287, + 571 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 548, + 287, + 571 + ], + "spans": [ + { + "bbox": [ + 55, + 548, + 287, + 571 + ], + "type": "text", + "content": "1. We first use an image backbone to extract image features from each image." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 54, + 578, + 287, + 614 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 578, + 287, + 614 + ], + "spans": [ + { + "bbox": [ + 54, + 578, + 287, + 614 + ], + "type": "text", + "content": "2. Then, a depth predictor is adopted to predict categorical depth distribution for each feature pixel to obtain the depth prediction." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 54, + 622, + 287, + 670 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 622, + 287, + 670 + ], + "spans": [ + { + "bbox": [ + 54, + 622, + 287, + 670 + ], + "type": "text", + "content": "3. After that, we send each image feature and corresponding depth to the Prime Extraction module, obtaining the Prime Feature and the Prime Depth, which is the compressed feature and depth." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 54, + 677, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 677, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 54, + 677, + 287, + 713 + ], + "type": "text", + "content": "4. Finally, with the Prime Feature, Prime Depth, and the pre-defined Ring & Ray Matrices, we use Eq. 6 (see also Fig. 1, lower) to obtain the BEV feature." + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 330, + 387, + 344 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 330, + 387, + 344 + ], + "spans": [ + { + "bbox": [ + 306, + 330, + 387, + 344 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 350, + 545, + 387 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 350, + 545, + 387 + ], + "spans": [ + { + "bbox": [ + 305, + 350, + 545, + 387 + ], + "type": "text", + "content": "In this section, we compare the performance, latency, and memory footprint of MatrixVT and other existing VT methods on the nuScenes benchmark [2]." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 396, + 440, + 408 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 396, + 440, + 408 + ], + "spans": [ + { + "bbox": [ + 305, + 396, + 440, + 408 + ], + "type": "text", + "content": "4.1. Implementation Details" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "spans": [ + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "type": "text", + "content": "We conduct our experiments based on BEVDepth [9], the current state-of-the-art detector on the nuScenes benchmark. In order to conduct a fair comparison of performance and efficiency, we re-implement BEVDepth according to their paper. Unless otherwise specified, we use ResNet50 [3] and VoVNet2-99 [8] pre-trained on DD3D [16] as the image backbone and SECOND FPN [31] as the image neck and BEV neck. The input image adopts pre-processing and data augmentations same as in [9]. We use BEV feature size " + }, + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "type": "inline_equation", + "content": "128 \\times 128" + }, + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "type": "text", + "content": " for low input resolution and " + }, + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "type": "inline_equation", + "content": "256 \\times 256" + }, + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "type": "text", + "content": " for high resolution on detection. Segmentation experiments use " + }, + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "type": "inline_equation", + "content": "200 \\times 200" + }, + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "type": "text", + "content": " BEV resolution as in LSS [17]. We use the DepthNet [9] to predict categorical depth from " + }, + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "type": "inline_equation", + "content": "2\\mathrm{m}" + }, + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "type": "inline_equation", + "content": "58\\mathrm{m}" + }, + { + "bbox": [ + 304, + 414, + 545, + 618 + ], + "type": "text", + "content": " in nuScenes, with uniform 112 division. During training, CBGS [34] and model EMA are adopted. Models are trained to converge since MatrixVT converges a little slower than other methods, but no more than 30 epochs." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 305, + 627, + 465, + 639 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 627, + 465, + 639 + ], + "spans": [ + { + "bbox": [ + 305, + 627, + 465, + 639 + ], + "type": "text", + "content": "4.2. Comparison of Performances" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 646, + 411, + 658 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 646, + 411, + 658 + ], + "spans": [ + { + "bbox": [ + 306, + 646, + 411, + 658 + ], + "type": "text", + "content": "4.2.1 Object Detection" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "We conduct experiments under several settings to evaluate the performance of MatrixVT in Tab. 1 and Tab. 2. On the nuScenes benchmark, we first adopt the ResNet family as the backbone without applying multi-frame fusion." + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "8552" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 71, + 547, + 252 + ], + "blocks": [ + { + "bbox": [ + 50, + 71, + 547, + 252 + ], + "lines": [ + { + "bbox": [ + 50, + 71, + 547, + 252 + ], + "spans": [ + { + "bbox": [ + 50, + 71, + 547, + 252 + ], + "type": "table", + "html": "
MethodBackboneResolutionMFmAP↑mATE↓mASE↓mAOE↓mAVE↓mAAE↓NDS↑
BEVDet [6]Res-50256 × 704×0.2860.7240.2780.5900.8730.2470.372
PETR [11]Res-50384 × 1056×0.3130.7680.2780.5640.9230.2250.381
BEVDepth [9]Res-50256 × 704×0.3370.6460.2710.5740.8380.2200.414
MatrixVTRes-50256 × 704×0.3360.6530.2710.4730.9030.2310.415
BEVDet [6]Res-101384 × 1056×0.3300.7020.2720.5340.9320.2510.396
FCOS3D [28]Res-101900 × 1600×0.3430.7250.2630.4221.2920.1530.415
PETR [11]Res-101512 × 1408×0.3570.7100.2700.4900.8850.2240.421
BEVFormer [10]R101-DCN900 × 1600×0.3750.7250.2720.3910.8020.2000.448
MatrixVTRes-101512 × 1408×0.3960.5770.2610.3970.8700.2070.467
BEVFormer [10]R101-DCN900 × 1600✓0.4160.6730.2740.3720.3940.1980.517
BEVDet4D [5]Swin-B640 × 1600✓0.4210.5790.2580.3290.3010.1910.545
BEVDepth [9]V2-99512 × 1408✓0.4640.5280.2540.3500.3540.1980.564
MatrixVTV2-99512 × 1408✓0.4660.5350.2600.3800.3420.1980.562
", + "image_path": "09df9ee9fe0938dad35376ee5e2e4d0119f41b017d0cab9fde125e66fdeefc99.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 50, + 290, + 288, + 335 + ], + "blocks": [ + { + "bbox": [ + 91, + 251, + 501, + 261 + ], + "lines": [ + { + "bbox": [ + 91, + 251, + 501, + 261 + ], + "spans": [ + { + "bbox": [ + 91, + 251, + 501, + 261 + ], + "type": "text", + "content": "Table 1. Experimental results of object detection on the nuScenes val set. The \"MF\" indicates multi-frame fusion." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 290, + 288, + 335 + ], + "lines": [ + { + "bbox": [ + 50, + 290, + 288, + 335 + ], + "spans": [ + { + "bbox": [ + 50, + 290, + 288, + 335 + ], + "type": "table", + "html": "
MethodBackbonemAP↑mAPH↑mAPL↑
BEVDepth [9]Res-500.2900.2080.253
MatrixVTRes-500.3040.2150.259
", + "image_path": "1a605d32f9e5723de0d42c911e19655279ccb4f6be11faf14a00c817df49d34e.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 376, + 287, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 376, + 287, + 521 + ], + "spans": [ + { + "bbox": [ + 46, + 376, + 287, + 521 + ], + "type": "text", + "content": "MatrixVT achieves " + }, + { + "bbox": [ + 46, + 376, + 287, + 521 + ], + "type": "inline_equation", + "content": "33.6\\%" + }, + { + "bbox": [ + 46, + 376, + 287, + 521 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 376, + 287, + 521 + ], + "type": "inline_equation", + "content": "49.7\\%" + }, + { + "bbox": [ + 46, + 376, + 287, + 521 + ], + "type": "text", + "content": " mAP with ResNet-50 and ResNet-101, which is comparable to the BEVDepth [9] and surpasses other methods by a large margin. We then test the upper bound of MatrixVT by replacing the backbone with V2-99 [8] pre-trained on external data and applying multi-frame fusion. Under this setting, MatrixVT achieves " + }, + { + "bbox": [ + 46, + 376, + 287, + 521 + ], + "type": "inline_equation", + "content": "46.6\\%" + }, + { + "bbox": [ + 46, + 376, + 287, + 521 + ], + "type": "text", + "content": " mAP and " + }, + { + "bbox": [ + 46, + 376, + 287, + 521 + ], + "type": "inline_equation", + "content": "56.2\\%" + }, + { + "bbox": [ + 46, + 376, + 287, + 521 + ], + "type": "text", + "content": " NDS, which is also comparable to the BEVDepth. Further, we validate if MatrixVT can be generalize to other benchmark. We conduct experiments on the Waymo benchmark [25], results show that MatrixVT still showing comparable or even better performance under this setting." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 538, + 161, + 551 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 538, + 161, + 551 + ], + "spans": [ + { + "bbox": [ + 47, + 538, + 161, + 551 + ], + "type": "text", + "content": "4.2.2 Map Segmentation" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 558, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 558, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 558, + 288, + 715 + ], + "type": "text", + "content": "We also conduct experiments on map segmentation tasks to validate the quality of the BEV feature generated by MatrixVT. To achieve this, we simply put a U-Net-like [22] segmentation head on the BEV feature. For fair comparison, we put the same head on the BEV feature of BEVDepth for experiments, and results are reported as \"BEVDepth-Seg\" in Tab. 3. It is worth noting that previous works achieve the best segmentation performance under different settings (different resolution, head structure, etc.); thus, we report the highest performance of each method. As can be seen from Tab. 3, the map segmentation performance of MatrixVT surpasses most existing methods on all three subtasks and is comparable to our baseline, BEVDepth." + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 309, + 290, + 545, + 380 + ], + "blocks": [ + { + "bbox": [ + 49, + 335, + 264, + 346 + ], + "lines": [ + { + "bbox": [ + 49, + 335, + 264, + 346 + ], + "spans": [ + { + "bbox": [ + 49, + 335, + 264, + 346 + ], + "type": "text", + "content": "Table 2. Performance of object detection on Waymo val set." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 309, + 290, + 545, + 380 + ], + "lines": [ + { + "bbox": [ + 309, + 290, + 545, + 380 + ], + "spans": [ + { + "bbox": [ + 309, + 290, + 545, + 380 + ], + "type": "table", + "html": "
MethodIoU-Drive↑IoU-Lane↑IoU-Vehicle↑
LSS [17]0.7290.2000.321
FIERY [4]--0.382
M2BEV [30]0.7590.380-
BEVFormer [10]0.7750.2390.467
BEVDepth-Seg0.8270.4640.450
MatrixVT0.8350.4480.462
", + "image_path": "c6f3c0aa70e03cd73750b35afe779319f95922a034f34707be6fea1430436157.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 380, + 545, + 414 + ], + "lines": [ + { + "bbox": [ + 306, + 380, + 545, + 414 + ], + "spans": [ + { + "bbox": [ + 306, + 380, + 545, + 414 + ], + "type": "text", + "content": "Table 3. Experimental results of BEV segmentation on the nuScenes val set. We implement map segmentation on the BEVDepth by placing a segmentation head on the BEV feature." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 443, + 444, + 455 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 443, + 444, + 455 + ], + "spans": [ + { + "bbox": [ + 306, + 443, + 444, + 455 + ], + "type": "text", + "content": "4.3. Efficient Transformation" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 461, + 545, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 461, + 545, + 653 + ], + "spans": [ + { + "bbox": [ + 304, + 461, + 545, + 653 + ], + "type": "text", + "content": "We compare the efficiency of View Transformation in two dimensions: Speed and Memory Consumption. Note that we measure the latency and memory footprint (using fp32) of view transformers since these metrics are affected by backbone and head design. We take the CPU as a representative general-purpose device where customized operators are unavailable. For a fair comparison, we measure and compare the other two Lift-Splat-like view transformers. The LS-BEVDet is the accelerated transformation used in BEVDet (with default parameters); the LS-BEVDepth uses the CUDA [14] operator proposed in BEVDepth [9] that is not available on CPU and other platforms. To demonstrate the characteristics of different methods, we define six transformation settings, namely S1~S6, varies in image feature size, BEV feature size, and feature channels that are closely related to model performance." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 653, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 547, + 715 + ], + "type": "text", + "content": "As can be seen in Fig. 5, the proposed MatrixVT boost the transformation significantly on the CPU, being 4 to 8 times faster than the LS-BEVDet[6]. On the CUDA platform [14], where customized operators enable faster transformation, MatrixVT still shows a much faster speed than" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8553" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 180, + 71, + 414, + 89 + ], + "blocks": [ + { + "bbox": [ + 180, + 71, + 414, + 89 + ], + "lines": [ + { + "bbox": [ + 180, + 71, + 414, + 89 + ], + "spans": [ + { + "bbox": [ + 180, + 71, + 414, + 89 + ], + "type": "image", + "image_path": "167e5a7a753d5e47c4cf4bd2389f2e2cb15c5ca2c4e43949673d39d555a9f20e.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 53, + 91, + 218, + 213 + ], + "blocks": [ + { + "bbox": [ + 53, + 91, + 218, + 213 + ], + "lines": [ + { + "bbox": [ + 53, + 91, + 218, + 213 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 218, + 213 + ], + "type": "image", + "image_path": "ded93cdc4bf4aef54294406476dfc3d52bbbc10d04ae3ba608d09bb52dce2614.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 220, + 546, + 253 + ], + "lines": [ + { + "bbox": [ + 46, + 220, + 546, + 253 + ], + "spans": [ + { + "bbox": [ + 46, + 220, + 546, + 253 + ], + "type": "text", + "content": "Figure 5. Latency (left, middle) and the number of intermediate parameters (right) of MatrixVT and two implementations of Lift-Splat, the S1~S6 denote transformation settings represented by image feature size " + }, + { + "bbox": [ + 46, + 220, + 546, + 253 + ], + "type": "inline_equation", + "content": "(C\\times H_I\\times W_I)" + }, + { + "bbox": [ + 46, + 220, + 546, + 253 + ], + "type": "text", + "content": " to BEV feature size " + }, + { + "bbox": [ + 46, + 220, + 546, + 253 + ], + "type": "inline_equation", + "content": "(C\\times H_B\\times W_B)" + }, + { + "bbox": [ + 46, + 220, + 546, + 253 + ], + "type": "text", + "content": ". Note that the LS-BEVDet raises Out Of Memory error under S5 and S6 on CUDA. The LS-BEVDepth is not available without the CUDA platform." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 219, + 91, + 380, + 213 + ], + "blocks": [ + { + "bbox": [ + 219, + 91, + 380, + 213 + ], + "lines": [ + { + "bbox": [ + 219, + 91, + 380, + 213 + ], + "spans": [ + { + "bbox": [ + 219, + 91, + 380, + 213 + ], + "type": "image", + "image_path": "eb4cee2494ada4bad1b00836d9134a3aea896492a8e3838bd96043a5d826731e.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 381, + 91, + 541, + 213 + ], + "blocks": [ + { + "bbox": [ + 381, + 91, + 541, + 213 + ], + "lines": [ + { + "bbox": [ + 381, + 91, + 541, + 213 + ], + "spans": [ + { + "bbox": [ + 381, + 91, + 541, + 213 + ], + "type": "image", + "image_path": "d546a5d926b953d7be6a60ab7721c0388dd5389fddd4a921c85a5a7925c74cb2.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 272, + 287, + 380 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 272, + 287, + 380 + ], + "spans": [ + { + "bbox": [ + 46, + 272, + 287, + 380 + ], + "type": "text", + "content": "the LS-BEVDepth under most settings. Besides, we calculate the number of intermediate variables during VT as an indicator of extra memory footprint. For MatrixVT, these variables include the Ring Matrix, Ray Matrix, and intermediate matrix; for Lift-Splat, intermediate variables include the intermediate tensor and the predefined BEV grids. As illustrated in Fig. 5 (right), MatrixVT consumes 2 to 15 times less memory than LS-BEVDepth and 40 to 80 times less memory than LS-BEVDet." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 380, + 287, + 487 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 380, + 287, + 487 + ], + "spans": [ + { + "bbox": [ + 46, + 380, + 287, + 487 + ], + "type": "text", + "content": "In Tab. 4, we adopt our proposed methods onto the BEVDepth step-by-step and evaluate improvements in memory footprint and latency. It can be seen that Prime Extraction effectively reduced memory footprint and latency by a large margin. For the low-resolution setting (Res-50 & 256), the Ring & Ray FTM further reduces the resource consumption. For the high-resolution setting (V2-99 & " + }, + { + "bbox": [ + 46, + 380, + 287, + 487 + ], + "type": "inline_equation", + "content": "512 \\times 1408" + }, + { + "bbox": [ + 46, + 380, + 287, + 487 + ], + "type": "text", + "content": "), the application of Ring & Ray FTM enabled VT without custom operators at cost of extra computation." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 495, + 132, + 506 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 495, + 132, + 506 + ], + "spans": [ + { + "bbox": [ + 47, + 495, + 132, + 506 + ], + "type": "text", + "content": "4.4. Effectiveness" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 513, + 287, + 548 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 513, + 287, + 548 + ], + "spans": [ + { + "bbox": [ + 46, + 513, + 287, + 548 + ], + "type": "text", + "content": "In this section, we validate the effectiveness of the proposed methods by performance comparison and visualization." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 563, + 180, + 574 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 563, + 180, + 574 + ], + "spans": [ + { + "bbox": [ + 47, + 563, + 180, + 574 + ], + "type": "text", + "content": "4.4.1 Effects on Performance" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "type": "text", + "content": "As mentioned in Sec. 3.2, we argue that the features and corresponding depths can be compressed with little or no information loss. We thus individually adopt the Prime Extraction and the Ring & Ray FTM onto the BEVDepth [9] to verify their effectiveness. To adopt Prime Extraction individually, we compress image features and the depths before the common Lift-Splat. As shown in Tab. 4, the BEVDepth with our improvements achieves " + }, + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "type": "inline_equation", + "content": "41.5\\%" + }, + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "type": "text", + "content": " NDS with Res-50 and " + }, + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "type": "inline_equation", + "content": "56.2\\%" + }, + { + "bbox": [ + 46, + 582, + 288, + 713 + ], + "type": "text", + "content": " NDS with VovNetv2-99 [8], which is comparable to the baseline. Thus, we argue that Prime Extraction effectively retained key information from raw features, and" + } + ] + } + ], + "index": 10 + }, + { + "type": "table", + "bbox": [ + 315, + 270, + 538, + 371 + ], + "blocks": [ + { + "bbox": [ + 315, + 270, + 538, + 371 + ], + "lines": [ + { + "bbox": [ + 315, + 270, + 538, + 371 + ], + "spans": [ + { + "bbox": [ + 315, + 270, + 538, + 371 + ], + "type": "table", + "html": "
BackbonePERRNDSMem.Lat. (ms)
Res-500.416528M1.79
Res-50✓0.41694M1.42
Res-50✓✓0.41583M1.33
V2-990.5642.14G8.85
V2-99✓0.563405M2.04
V2-99✓✓0.562498M3.19
", + "image_path": "201b567a5a280ebcb72498bb571dc4e075170d7ca0822aaf5834015eeb98cdef.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 371, + 545, + 414 + ], + "lines": [ + { + "bbox": [ + 305, + 371, + 545, + 414 + ], + "spans": [ + { + "bbox": [ + 305, + 371, + 545, + 414 + ], + "type": "text", + "content": "Table 4. Effects of using Prime Extraction (PE) and Ring & Ray FTM (RR) on BEVDepth. The memory consumption and latency reported is the memory footprint and time duration on PyTorch during View Transformation (VT)." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 305, + 445, + 545, + 469 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 445, + 545, + 469 + ], + "spans": [ + { + "bbox": [ + 305, + 445, + 545, + 469 + ], + "type": "text", + "content": "the application of Ring & Ray FTM would not harm the final performance." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 487, + 504, + 499 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 487, + 504, + 499 + ], + "spans": [ + { + "bbox": [ + 306, + 487, + 504, + 499 + ], + "type": "text", + "content": "4.4.2 Prime Information in Object Detection" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 507, + 545, + 639 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 507, + 545, + 639 + ], + "spans": [ + { + "bbox": [ + 304, + 507, + 545, + 639 + ], + "type": "text", + "content": "We then delve into the mechanism of Prime Extraction by visualization. Fig. 6 shows the inputs and outputs of the Prime Extraction module. It can be seen that the Prime Extraction module trained on different tasks focusing on different information. The Prime Depth Attention in object detection focuses on foreground objects. Thus the Prime Depth retained the depth of objects while ignoring the depth of the background. Also, it can be seen from the yellow car in the second column, which is obscured by three pedestrians. Prime Extraction effectively distinguishes these objects at different depths." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 658, + 514, + 670 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 658, + 514, + 670 + ], + "spans": [ + { + "bbox": [ + 306, + 658, + 514, + 670 + ], + "type": "text", + "content": "4.4.3 Prime Information in Map Segmentation" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 305, + 677, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 546, + 713 + ], + "type": "text", + "content": "For the map segmentation task, we take lane segmentation as an example — the Prime Extraction module focus on lane and road that is closely related to this task. However, since" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8554" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 55, + 74, + 547, + 300 + ], + "blocks": [ + { + "bbox": [ + 55, + 74, + 547, + 300 + ], + "lines": [ + { + "bbox": [ + 55, + 74, + 547, + 300 + ], + "spans": [ + { + "bbox": [ + 55, + 74, + 547, + 300 + ], + "type": "image", + "image_path": "9b94ca56bbfb5a908de8c332f591a76603595681acf1e0f907267d2c73181453.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 301, + 546, + 324 + ], + "lines": [ + { + "bbox": [ + 46, + 301, + 546, + 324 + ], + "spans": [ + { + "bbox": [ + 46, + 301, + 546, + 324 + ], + "type": "text", + "content": "Figure 6. Depth Prediction, Prime Depth Attention, and Prime Depth for object detection and lane segmentation task. The categorical depth prediction is illustrated using distances with largest probability, while the Prime Depth is illustrated by raw probability values." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 343, + 289, + 440 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 343, + 289, + 440 + ], + "spans": [ + { + "bbox": [ + 46, + 343, + 289, + 440 + ], + "type": "text", + "content": "the area of the target category is a wide range covering several depth bins, the distribution of Prime Depth is uniform in the target area (see Fig. 6, 3rd and 4th columns). The observation indicates that Prime Extraction generates a new form of depth distribution that fits the map segmentation task. With the Prime Depth that is rather uniform, the same feature can be projected to multiple depth bins since they are occupied by the same category." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 451, + 202, + 463 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 451, + 202, + 463 + ], + "spans": [ + { + "bbox": [ + 47, + 451, + 202, + 463 + ], + "type": "text", + "content": "4.5. Extraction of Prime Feature" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 472, + 287, + 543 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 472, + 287, + 543 + ], + "spans": [ + { + "bbox": [ + 46, + 472, + 287, + 543 + ], + "type": "text", + "content": "In the Prime Feature Extractor, we propose using max pooling followed by several 1D convolutions to reduce and refine the image feature. Before reduction, the coordinate of each pixel is embedded into the feature as position embedding. We conduct experiments to validate the contribution of each design." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 544, + 287, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 544, + 287, + 676 + ], + "spans": [ + { + "bbox": [ + 46, + 544, + 287, + 676 + ], + "type": "text", + "content": "A possible alternative of the max pooling is the CollapseConv as in [18] and [20], which merges the height dimension into the channel dimension and reduces the merged channel by linear projection. However, the design of CollapseConv brings some disadvantages. For example, the merged dimension is of size " + }, + { + "bbox": [ + 46, + 544, + 287, + 676 + ], + "type": "inline_equation", + "content": "C \\times H" + }, + { + "bbox": [ + 46, + 544, + 287, + 676 + ], + "type": "text", + "content": ", which is high and requires extra memory transportation. To address these problems, we propose using max pooling to reduce the image feature in Prime Extraction. Tab. 5 shows that reduction using max pooling achieves even better performance than CollapseConv while eliminating these shortcomings." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 677, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 288, + 714 + ], + "type": "text", + "content": "We also conduct experiments to show the effectiveness of the refine sub-net after reducing in Tab. 5. The results indicate that the refine sub-net plays a vital role in adapting" + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 310, + 342, + 542, + 413 + ], + "blocks": [ + { + "bbox": [ + 310, + 342, + 542, + 413 + ], + "lines": [ + { + "bbox": [ + 310, + 342, + 542, + 413 + ], + "spans": [ + { + "bbox": [ + 310, + 342, + 542, + 413 + ], + "type": "table", + "html": "
ReductionRefinePos. Emb.mAPNDS
Max Pooling0.3280.393
Max Pooling✓0.3320.414
Max Pooling✓✓0.3360.415
CollapseConv✓✓0.3340.404
", + "image_path": "307ea17f8b5e6c885169a27fe2deca8d0a87fd3dee4f33cf05a5ef7b45c98a74.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 413, + 545, + 445 + ], + "lines": [ + { + "bbox": [ + 306, + 413, + 545, + 445 + ], + "spans": [ + { + "bbox": [ + 306, + 413, + 545, + 445 + ], + "type": "text", + "content": "Table 5. Performance of MatrixVT with different feature reduction methods. The \"Refine\" indicates the refine convs, the \"Pos.Emb.\" indicates using front-view position embedding." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 305, + 475, + 545, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 475, + 545, + 536 + ], + "spans": [ + { + "bbox": [ + 305, + 475, + 545, + 536 + ], + "type": "text", + "content": "the reduced feature to BEV space, without which a performance drop of " + }, + { + "bbox": [ + 305, + 475, + 545, + 536 + ], + "type": "inline_equation", + "content": "0.9\\%" + }, + { + "bbox": [ + 305, + 475, + 545, + 536 + ], + "type": "text", + "content": " mAP will occur. Finally, the experimental results in Tab. 5 have shown that the position embedding brings an improvement of " + }, + { + "bbox": [ + 305, + 475, + 545, + 536 + ], + "type": "inline_equation", + "content": "0.4\\%" + }, + { + "bbox": [ + 305, + 475, + 545, + 536 + ], + "type": "text", + "content": " mAP, which is also preferable." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 545, + 378, + 558 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 545, + 378, + 558 + ], + "spans": [ + { + "bbox": [ + 306, + 545, + 378, + 558 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 566, + 545, + 697 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 566, + 545, + 697 + ], + "spans": [ + { + "bbox": [ + 304, + 566, + 545, + 697 + ], + "type": "text", + "content": "This paper proposes a new paradigm of View Transformation (VT) from multi-camera to Bird's-Eye-View. The proposed method, MatrixVT, generalizes VT into a feature transportation matrix. We then propose Prime Extraction, which eliminates the redundancy during transformation, and the Ring & Ray Decomposition, which simplifies and boost the transformation. While being faster and more efficient on both specialized devices like GPU and general-purpose devices like CPU, our extensive experiments on the nuScenes benchmark indicate that the MatrixVT offers comparable performance to the state-of-the-art method." + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8555" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 107, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 107, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 107, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 714 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 157 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 157 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 157 + ], + "type": "text", + "content": "[1] Xuyang Bai, Zeyu Hu, Xinge Zhu, Qingqiu Huang, Yilun Chen, Hongbo Fu, and Chiew-Lan Tai. Transfusion: Robust lidar-camera fusion for 3d object detection with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1090-1099, 2022. 1, 4" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 159, + 288, + 236 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 159, + 288, + 236 + ], + "spans": [ + { + "bbox": [ + 53, + 159, + 288, + 236 + ], + "type": "text", + "content": "[2] Holger Caesar, Varun Bankiti, Alex H. Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2020, Seattle, WA, USA, June 13-19, 2020, pages 11618-11628. IEEE, 2020. 2, 5" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 237, + 287, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 237, + 287, + 293 + ], + "spans": [ + { + "bbox": [ + 53, + 237, + 287, + 293 + ], + "type": "text", + "content": "[3] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In 2016 IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2016, Las Vegas, NV, USA, June 27-30, 2016, pages 770-778. IEEE Computer Society, 2016. 5" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 294, + 287, + 360 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 294, + 287, + 360 + ], + "spans": [ + { + "bbox": [ + 53, + 294, + 287, + 360 + ], + "type": "text", + "content": "[4] Anthony Hu, Zak Murez, Nikhil Mohan, Sofia Dudas, Jeffrey Hawke, Vijay Badrinarayanan, Roberto Cipolla, and Alex Kendall. Fiery: Future instance prediction in bird's-eye view from surround monocular cameras. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 15273-15282, 2021. 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 362, + 287, + 395 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 362, + 287, + 395 + ], + "spans": [ + { + "bbox": [ + 53, + 362, + 287, + 395 + ], + "type": "text", + "content": "[5] Junjie Huang and Guan Huang. Bevdet4d: Exploit temporal cues in multi-camera 3d object detection. ArXiv preprint, abs/2203.17054, 2022. 1, 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 396, + 287, + 441 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 396, + 287, + 441 + ], + "spans": [ + { + "bbox": [ + 53, + 396, + 287, + 441 + ], + "type": "text", + "content": "[6] Junjie Huang, Guan Huang, Zheng Zhu, and Dalong Du. Bevdet: High-performance multi-camera 3d object detection in bird-eye-view. ArXiv preprint, abs/2112.11790, 2021. 1, 2, 3, 6" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 442, + 287, + 509 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 442, + 287, + 509 + ], + "spans": [ + { + "bbox": [ + 53, + 442, + 287, + 509 + ], + "type": "text", + "content": "[7] Alex H. Lang, Sourabh Vora, Holger Caesar, Lubing Zhou, Jiong Yang, and Oscar Beijbom. Pointpillars: Fast encoders for object detection from point clouds. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 12697-12705. Computer Vision Foundation / IEEE, 2019. 2, 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 510, + 287, + 564 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 510, + 287, + 564 + ], + "spans": [ + { + "bbox": [ + 53, + 510, + 287, + 564 + ], + "type": "text", + "content": "[8] Youngwan Lee and Jongyoul Park. Centermask: Real-time anchor-free instance segmentation. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2020, Seattle, WA, USA, June 13-19, 2020, pages 13903-13912. IEEE, 2020. 5, 6, 7" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 567, + 287, + 620 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 567, + 287, + 620 + ], + "spans": [ + { + "bbox": [ + 53, + 567, + 287, + 620 + ], + "type": "text", + "content": "[9] Yinhao Li, Zheng Ge, Guanyi Yu, Jinrong Yang, Zengran Wang, Yukang Shi, Jianjian Sun, and Zeming Li. Bevdepth: Acquisition of reliable depth for multi-view 3d object detection. ArXiv preprint, abs/2206.10092, 2022. 1, 2, 3, 5, 6, 7" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 623, + 287, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 623, + 287, + 678 + ], + "spans": [ + { + "bbox": [ + 48, + 623, + 287, + 678 + ], + "type": "text", + "content": "[10] Zhiqi Li, Wenhai Wang, Hongyang Li, Enze Xie, Chonghao Sima, Tong Lu, Qiao Yu, and Jifeng Dai. BEV-Former: Learning Bird's-Eye-View Representation from Multi-Camera Images via Spatiotemporal Transformers. ArXiv preprint, abs/2203.17270, 2022. 1, 2, 6" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 680, + 287, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 680, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 48, + 680, + 287, + 714 + ], + "type": "text", + "content": "[11] Yingfei Liu, Tiancai Wang, Xiangyu Zhang, and Jian Sun. Petr: Position embedding transformation for multi-view 3d object detection. ArXiv preprint, abs/2203.05625, 2022. 2, 6" + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 714 + ], + "type": "list", + "angle": 0, + "index": 26, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 117 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 117 + ], + "type": "text", + "content": "[12] Zhijian Liu, Haotian Tang, Alexander Amini, Xinyu Yang, Huizi Mao, Daniela Rus, and Song Han. Bevfusion: Multitask multi-sensor fusion with unified bird's-eye view representation. arXiv preprint arXiv:2205.13542, 2022. 1" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 307, + 118, + 545, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 545, + 162 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 545, + 162 + ], + "type": "text", + "content": "[13] Hanspeter A Mallot, Heinrich H Bülthoff, JJ Little, and Stefan Bohrer. Inverse perspective mapping simplifies optical flow computation and obstacle detection. Biological cybernetics, 64(3):177-185, 1991. 1" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 163, + 545, + 185 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 163, + 545, + 185 + ], + "spans": [ + { + "bbox": [ + 307, + 163, + 545, + 185 + ], + "type": "text", + "content": "[14] NVIDIA, Péter Vingelmann, and Frank H.P. Fitzek. Cuda, release: 10.2.89, 2020. 6" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 186, + 545, + 230 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 186, + 545, + 230 + ], + "spans": [ + { + "bbox": [ + 308, + 186, + 545, + 230 + ], + "type": "text", + "content": "[15] Bowen Pan, Jiankai Sun, Ho Yin Tiga Leung, Alex Andonian, and Bolei Zhou. Cross-view semantic segmentation for sensing surroundings. IEEE Robotics and Automation Letters, 5(3):4867-4873, 2020. 1" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 232, + 545, + 275 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 232, + 545, + 275 + ], + "spans": [ + { + "bbox": [ + 308, + 232, + 545, + 275 + ], + "type": "text", + "content": "[16] Dennis Park, Rares Ambrus, Vitor Guizilini, Jie Li, and Adrien Gaidon. Is pseudo-lidar needed for monocular 3d object detection? In IEEE/CVF International Conference on Computer Vision (ICCV), 2021. 5" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 277, + 545, + 320 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 277, + 545, + 320 + ], + "spans": [ + { + "bbox": [ + 308, + 277, + 545, + 320 + ], + "type": "text", + "content": "[17] Jonah Philion and Sanja Fidler. Lift, splat, shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3d. In European Conference on Computer Vision, pages 194-210. Springer, 2020. 1, 2, 3, 5, 6" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 322, + 545, + 376 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 322, + 545, + 376 + ], + "spans": [ + { + "bbox": [ + 308, + 322, + 545, + 376 + ], + "type": "text", + "content": "[18] Cody Reading, Ali Harakeh, Julia Chae, and Steven L. Waslander. Categorical depth distribution network for monocular 3d object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 8555-8564, 2021. 1, 2, 8" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 378, + 545, + 444 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 378, + 545, + 444 + ], + "spans": [ + { + "bbox": [ + 308, + 378, + 545, + 444 + ], + "type": "text", + "content": "[19] Lennart Reiher, Bastian Lampe, and Lutz Eckstein. A sim2real deep learning approach for the transformation of images from multiple vehicle-mounted cameras to a semantically segmented image in bird's eye view. In 2020 IEEE 23rd International Conference on Intelligent Transportation Systems (ITSC), pages 1-7. IEEE, 2020. 1" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 445, + 545, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 445, + 545, + 510 + ], + "spans": [ + { + "bbox": [ + 308, + 445, + 545, + 510 + ], + "type": "text", + "content": "[20] Thomas Roddick and Roberto Cipolla. Predicting semantic map representations from images using pyramid occupancy networks. In 2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2020, Seattle, WA, USA, June 13-19, 2020, pages 11135-11144. IEEE, 2020. 1, 2, 4, 8" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 512, + 545, + 567 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 512, + 545, + 567 + ], + "spans": [ + { + "bbox": [ + 308, + 512, + 545, + 567 + ], + "type": "text", + "content": "[21] Thomas Roddick, Alex Kendall, and Roberto Cipolla. Orthographic feature transform for monocular 3d object detection. In 30th British Machine Vision Conference 2019, BMVC 2019, Cardiff, UK, September 9-12, 2019, page 285. BMVA Press, 2019. 1, 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 568, + 545, + 623 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 568, + 545, + 623 + ], + "spans": [ + { + "bbox": [ + 308, + 568, + 545, + 623 + ], + "type": "text", + "content": "[22] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image computing and computer-assisted intervention, pages 234-241. Springer, 2015. 2, 6" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 624, + 545, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 624, + 545, + 678 + ], + "spans": [ + { + "bbox": [ + 308, + 624, + 545, + 678 + ], + "type": "text", + "content": "[23] Daeyun Shin, Zhile Ren, Erik B Sudderth, and Charless C Fowlkes. 3d scene reconstruction with multi-layer depth and epipolar transformers. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 2172-2182, 2019. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 680, + 545, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 680, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 308, + 680, + 545, + 714 + ], + "type": "text", + "content": "[24] Siddharth Srivastava, Frederic Jurie, and Gaurav Sharma. Learning 2d to 3d lifting for object detection in 3d for autonomous vehicles. In 2019 IEEE/RSJ International Confer-" + } + ] + } + ], + "index": 25 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "8556" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 662 + ], + "type": "list", + "angle": 0, + "index": 11, + "blocks": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "text", + "content": "ence on Intelligent Robots and Systems (IROS), pages 4504-4511. IEEE, 2019. 1, 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 205 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 205 + ], + "type": "text", + "content": "[25] Pei Sun, Henrik Kretzschmar, Xerxes Dotiwalla, Aurelien Chouard, Vijaysai Patnaik, Paul Tsui, James Guo, Yin Zhou, Yuning Chai, Benjamin Caine, Vijay Vasudevan, Wei Han, Jiquan Ngiam, Hang Zhao, Aleksei Timofeev, Scott Ettinger, Maxim Krivokon, Amy Gao, Aditya Joshi, Yu Zhang, Jonathon Shlens, Zhifeng Chen, and Dragomir Anguelov. Scalability in perception for autonomous driving: Waymo open dataset. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), June 2020. 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 207, + 287, + 261 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 207, + 287, + 261 + ], + "spans": [ + { + "bbox": [ + 48, + 207, + 287, + 261 + ], + "type": "text", + "content": "[26] Zhi Tian, Chunhua Shen, Hao Chen, and Tong He. FCOS: fully convolutional one-stage object detection. In 2019 IEEE/CVF International Conference on Computer Vision, ICCV 2019, Seoul, Korea (South), October 27 - November 2, 2019, pages 9626-9635. IEEE, 2019. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 262, + 287, + 305 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 262, + 287, + 305 + ], + "spans": [ + { + "bbox": [ + 48, + 262, + 287, + 305 + ], + "type": "text", + "content": "[27] Tai Wang, ZHU Xinge, Jiangmiao Pang, and Dahua Lin. Probabilistic and geometric depth: Detecting objects in perspective. In Conference on Robot Learning, pages 1475-1485. PMLR, 2022. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 308, + 287, + 351 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 308, + 287, + 351 + ], + "spans": [ + { + "bbox": [ + 48, + 308, + 287, + 351 + ], + "type": "text", + "content": "[28] Tai Wang, Xinge Zhu, Jiangmiao Pang, and Dahua Lin. Fcos3d: Fully convolutional one-stage monocular 3d object detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 913-922, 2021. 2, 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 353, + 287, + 428 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 353, + 287, + 428 + ], + "spans": [ + { + "bbox": [ + 48, + 353, + 287, + 428 + ], + "type": "text", + "content": "[29] Yan Wang, Wei-Lun Chao, Divyansh Garg, Bharath Hariharan, Mark E. Campbell, and Kilian Q. Weinberger. Pseudolidar from visual depth estimation: Bridging the gap in 3d object detection for autonomous driving. In IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 8445-8453. Computer Vision Foundation / IEEE, 2019. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 430, + 287, + 483 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 430, + 287, + 483 + ], + "spans": [ + { + "bbox": [ + 48, + 430, + 287, + 483 + ], + "type": "text", + "content": "[30] Enze Xie, Zhiding Yu, Daquan Zhou, Jonah Philion, Anima Anandkumar, Sanja Fidler, Ping Luo, and Jose M Alvarez. M^2bev: Multi-camera joint 3d detection and segmentation with unified birds-eye view representation. ArXiv preprint, abs/2204.05088, 2022. 1, 6" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 486, + 287, + 517 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 486, + 287, + 517 + ], + "spans": [ + { + "bbox": [ + 48, + 486, + 287, + 517 + ], + "type": "text", + "content": "[31] Yan Yan, Yuxing Mao, and Bo Li. Second: Sparsely embedded convolutional detection. Sensors, 18(10):3337, 2018. 2, 5" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 519, + 287, + 563 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 519, + 287, + 563 + ], + "spans": [ + { + "bbox": [ + 48, + 519, + 287, + 563 + ], + "type": "text", + "content": "[32] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Center-based 3d object detection and tracking. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 11784-11793, 2021. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 565, + 287, + 619 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 565, + 287, + 619 + ], + "spans": [ + { + "bbox": [ + 48, + 565, + 287, + 619 + ], + "type": "text", + "content": "[33] Yin Zhou and Oncel Tuzel. Voxelnet: End-to-end learning for point cloud based 3d object detection. In 2018 IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2018, Salt Lake City, UT, USA, June 18-22, 2018, pages 4490-4499. IEEE Computer Society, 2018. 2, 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 620, + 287, + 662 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 620, + 287, + 662 + ], + "spans": [ + { + "bbox": [ + 48, + 620, + 287, + 662 + ], + "type": "text", + "content": "[34] Benjin Zhu, Zhengkai Jiang, Xiangxin Zhou, Zeming Li, and Gang Yu. Class-balanced grouping and sampling for point cloud 3d object detection. ArXiv preprint, abs/1908.09492, 2019. 5" + } + ] + } + ], + "index": 10 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8557" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/40deaafe-8b86-4716-a18c-f883acf32105_content_list.json b/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/40deaafe-8b86-4716-a18c-f883acf32105_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..3bbdce7c5526f1964783ef75bb08c2e0b60a463b --- /dev/null +++ b/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/40deaafe-8b86-4716-a18c-f883acf32105_content_list.json @@ -0,0 +1,1637 @@ +[ + { + "type": "text", + "text": "MeMOTR: Long-Term Memory-Augmented Transformer for Multi-Object Tracking", + "text_level": 1, + "bbox": [ + 192, + 130, + 779, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Ruopeng Gao $^{1}$ Limin Wang $^{1,2,\\text{四}}$", + "bbox": [ + 316, + 203, + 651, + 220 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{1}$ State Key Laboratory for Novel Software Technology, Nanjing University $^{2}$ Shanghai AI Lab", + "bbox": [ + 106, + 220, + 864, + 239 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 287, + 313, + 305 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "As a video task, Multiple Object Tracking (MOT) is expected to capture temporal information of targets effectively. Unfortunately, most existing methods only explicitly exploit the object features between adjacent frames, while lacking the capacity to model long-term temporal information. In this paper, we propose MeMOTR, a long-term memory-augmented Transformer for multi-object tracking. Our method is able to make the same object's track embedding more stable and distinguishable by leveraging long-term memory injection with a customized memory-attention layer. This significantly improves the target association ability of our model. Experimental results on DanceTrack show that MeMOTR impressively surpasses the state-of-the-art method by $7.9\\%$ and $13.0\\%$ on HOTA and AssA metrics, respectively. Furthermore, our model also outperforms other Transformer-based methods on association performance on MOT17 and generalizes well on BDD100K. Code is available at https://github.com/MCG-NJU/MeMOTR.", + "bbox": [ + 75, + 320, + 473, + 593 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 623, + 209, + 638 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Multi-Object Tracking (MOT) [8, 23, 29] aims to detect multiple objects and maintain their identities in a video stream. MOT can be applied to numerous downstream tasks, such as action recognition [7], behavior analysis [16], and so on. It is also an important technique for real-world applications, e.g., autonomous driving and surveillance.", + "bbox": [ + 75, + 648, + 468, + 739 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "According to the definition of MOT, this task can be formally divided into two parts: object detection and association. For a long time, pedestrian tracking datasets (like MOT17 [23]) have had mainstream domination in the community. However, these datasets have insufficient challenges in target association because of their almost linear motion pattern. Therefore, tracking-by-detection methods [5, 32, 43] achieve the state-of-the-art performance of MOT for several years. They first adopt a robust object de", + "bbox": [ + 75, + 739, + 470, + 877 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "tector (e.g., YOLOX [12]) to independently localize the objects in each frame and associate them with IoU [3, 40] or ReID features [26]. However, associating targets becomes a critical challenge in some complex scenarios, like group dancers [29] and sports players [8, 13]. These similar appearances and erratic movements may cause existing methods to fail. Recently, Transformer-based tracking methods [22, 42] have introduced a new fully-end-to-end MOT paradigm. Through the interaction and progressive decoding of detect and track queries in Transformer, they simultaneously complete detection and tracking. This paradigm is expected to have greater potential for object association due to the flexibility of Transformer, especially in the above complex scenes.", + "bbox": [ + 496, + 275, + 893, + 486 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Although these Transformer-based methods achieve excellent performance, they still struggle with some complicated issues, such as analogous appearances, irregular motion patterns, and long-term occlusions. We hypothesize that more intelligent leverage of temporal information can provide the tracker a more effective and robust representation for each tracked target, thereby relieving the above issues and boosting the tracking performance. Unfortunately, most previous methods [22, 42] only exploit the image or object features between two adjacent frames, which lacking the utilization of long-term temporal information.", + "bbox": [ + 496, + 488, + 895, + 655 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Based on the analysis above, in this paper, we focus on leveraging temporal information by proposing a long-term Memory-augmented Multi-Object Tracking method with TRansformer, coined as MeMOTR. We exploit detect and track embeddings to localize newborn and tracked objects via a Transformer Decoder, respectively. Our model maintains a long-term memory with the exponential recursion update algorithm [28] for each tracked object. Afterward, we inject this memory into the track embedding, reducing its abrupt changes and thus improving the model association ability. As multiple tracked targets exist in a video stream, we apply a memory-attention layer to produce a more distinguishable representation. Besides, we present an adaptive aggregation to fuse the object feature from two adjacent frames to improve tracking robustness.", + "bbox": [ + 496, + 656, + 895, + 883 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In addition, we argue that the learnable detection query", + "bbox": [ + 517, + 885, + 890, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "$\\boxtimes$ : Corresponding author (lmwang@nju.edu.cn).", + "bbox": [ + 99, + 887, + 364, + 900 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "9901", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "in DETR [6] has no semantic information about specific objects. However, the track query in Transformer-based MOT methods like MOTR [42] carries information about a tracked object. This difference will cause a semantic information gap and thus degrade the final tracking performance. Therefore, to overcome this issue, we use a light decoder to perform preliminary object detection, which outputs the detect embedding with specific semantics. Then we jointly input detect and track embeddings into the subsequent decoder to make MeMOTR tracking results more precise.", + "bbox": [ + 75, + 90, + 468, + 241 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We mainly evaluate our method on the DanceTrack dataset [29] because of its serious association challenge. Experimental results show that our method achieves the state-of-the-art performance on this challenging DanceTrack dataset, especially on association metrics (e.g., AssA, IDF1). We also evaluate our model on the traditional pedestrian tracking dataset of MOT17 [23] and the multicategories tracking dataset of BDD100K [41]. In addition, we perform extensive ablation studies further demonstrate the effectiveness of our designs.", + "bbox": [ + 75, + 242, + 470, + 393 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 76, + 407, + 218, + 422 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Tracking-by-Detection is a widely used MOT paradigm that has recently dominated the community. These methods always get trajectories by associating a given set of detections in a streaming video.", + "bbox": [ + 75, + 431, + 468, + 492 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The objects in classic pedestrian tracking scenarios [9, 23] always have different appearances and regular motion patterns. Therefore, appearance matching and linear motion estimation are widely used to match targets in consecutive frames. SORT [3] uses the Intersection-over-Union (IoU) to match predictions of the Kalman filter [33] and detected boxes. Deep-SORT [34] applies an additional network to extract target features, then utilizes cosine distances for matching besides motion consideration in SORT [3]. JDE [32], FairMOT [44], and Unicorn [38] further explore the architecture of appearance embedding and matching. ByteTrack [43] employs a robust detector based onYOLOX [12] and reuses low-confidence detections to enhance the association ability. Furthermore, OC-SORT [5] improves SORT [3] by rehabilitating lost targets. In recent years, as a trendy framework in vision tasks, some studies [35, 47] have also applied Transformers to match detection bounding boxes. Moreover, Dendorfer et al. [10] attempt to model pedestrian trajectories by leveraging more complex motion estimation methods (like S-GAN [14]) from the trajectory prediction task.", + "bbox": [ + 75, + 492, + 470, + 809 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The methods described above have powerful detection capabilities due to their robust detectors. However, although such methods have achieved outstanding performance in pedestrian tracking datasets, they are mediocre at dealing with more complex scenarios having irregular movements. These unforeseeable motion patterns will cause the trajec", + "bbox": [ + 75, + 810, + 468, + 902 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "tory estimation and prediction module to fail.", + "bbox": [ + 498, + 90, + 799, + 106 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Tracking-by-Query usually does not require additional post-processing to associate detection results. Unlike the tracking-by-detection paradigm mentioned above, tracking-by-query methods apply the track query to decode the location of tracked objects progressively.", + "bbox": [ + 496, + 107, + 890, + 183 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Inspired by DETR-family [6], most of these methods [22, 42] leverage the learnable object query to perform newborn object detection, while the track query localizes the position of tracked objects. TransTrack [30] builds a siamese network for detection and tracking, then applies an IoU matching to produce newborn targets. TrackFormer [22] utilizes the same Transformer decoder for both detection and tracking, then employs a nonmaximum suppression (NMS) with a high IoU threshold to remove strongly overlapping duplicate bounding boxes. MOTR [42] builds an elegant and fully end-to-end Transformer for multi-object tracking. This paradigm performs excellently in dealing with irregular movements due to the flexibility of query-based design. Furthermore, MQT [17] employs different queries to represent one tracked object and cares more about class-agnostic tracking.", + "bbox": [ + 496, + 183, + 892, + 425 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "However, current query-based methods typically exploit the information of adjacent frames (query [42] or feature [22] fusion). Although the track query can be continuously updated over time, most methods still do not explicitly exploit longer temporal information. Cai et al. [4] explore a large memory bank to benefit from time-related knowledge but suffer enormous storage costs. In order to use long-term information, we propose a long-term memory to stabilize the tracked object feature over time and a memory-attention layer for a more distinguishable representation. Our experiments further approve that this approach significantly improves association performance in MOT.", + "bbox": [ + 496, + 426, + 893, + 608 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "3. Method", + "text_level": 1, + "bbox": [ + 500, + 623, + 591, + 638 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "3.1. Overview", + "text_level": 1, + "bbox": [ + 500, + 648, + 609, + 662 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We propose the MeMOTR, a long-term memory-augmented Transformer for multi-object tracking. Different from most existing methods [22, 42] that only explicitly utilize the states of tracked objects between adjacent frames, our core contribution is to build a long-term memory (in Section 3.3) that maintains the long-term temporal feature for each tracked target, together with a temporal interaction module (TIM) that effectively injects the temporal information into subsequent tracking processes.", + "bbox": [ + 496, + 672, + 890, + 808 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Like most DETR-family methods [6], we use a ResNet-50 [15] backbone and a Transformer Encoder to produce the image feature of an input frame $I^t$ . As shown in Figure 1, the learnable detect query $Q_{det}$ is fed into the Detection Decoder $\\mathcal{D}_{det}$ (in Section 3.2) to generate the detect embedding $E_{det}^{t}$ for the current frame. Afterward, by query", + "bbox": [ + 496, + 810, + 890, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "9902", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/0bd298b495f0935e5b2fbce12b108fdc8db7e6f6e91d78be73382ed509911d08.jpg", + "image_caption": [ + "Figure 1. Overview of MeMOTR. Like most DETR-based [6] methods, we exploit a ResNet-50 [15] backbone and a Transformer [31] Encoder to learn a 2D representation of an input image. We use different colors to indicate different tracked targets, and the learnable detect query $Q_{det}$ is illustrated in gray. Then the Detection Decoder $\\mathcal{D}_{det}$ processes the detect query to generate the detect embedding $E_{det}^{t}$ , which aligns with the track embedding $E_{tck}^{t}$ from previous frames. Long-term memory is denoted as $M_{tck}^{t}$ . The initialization process in the blue dotted arrow will be applied to newborn objects. Our Long-Term Memory and Temporal Interaction Module is discussed in Section 3.3 and 3.4. More details are illustrated in Figure 2." + ], + "image_footnote": [], + "bbox": [ + 86, + 93, + 883, + 277 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "ing the encoded image feature with $[E_{det}^{t}, E_{tck}^{t}]$ , the Transformer Joint Decoder $\\mathcal{D}_{joint}$ produces the corresponding output $[\\hat{O}_{det}^{t}, \\hat{O}_{tck}^{t}]$ . For simplicity, we merge the newborn objects in $\\hat{O}_{det}^{t}$ (yellow box) with tracked objects' output $\\hat{O}_{tck}^{t}$ , denoted by $O_{tck}^{t}$ . Afterward, we predict the classification confidence $c_{i}^{t}$ and bounding box $b_{i}^{t}$ corresponding to the $i^{th}$ target from the output embeddings. Finally, we feed the output from adjacent frames $[O_{tck}^{t}, O_{tck}^{t-1}]$ and the long-term memory $M_{tck}^{t}$ into the Temporal Interaction Module, updating the subsequent track embedding $E_{tck}^{t+1}$ and long-term memory $M_{tck}^{t+1}$ . The details of our components will be elaborated in the following sections.", + "bbox": [ + 75, + 400, + 472, + 587 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Detection Decoder", + "text_level": 1, + "bbox": [ + 76, + 602, + 254, + 616 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In the previous Transformer-based methods [22, 42], the learnable detect query and the previous track query are jointly input to Transformer Decoder from scratch. This simple idea extends the end-to-end detection Transformer [6] to multi-object tracking. Nonetheless, we argue that this design may cause misalignment between detect and track queries. As discussed in numerous works [6, 20], the learnable object query in DETR-family plays a role similar to a learnable anchor with little semantic information. On the other hand, track queries have specific semantic knowledge to resolve their category and bounding boxes since they are generated from the output of previous frames.", + "bbox": [ + 75, + 627, + 468, + 808 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Therefore, as illustrated in Figure 1, we split the original Transformer Decoder into two parts. The first decoder layer is used for detection, and the remaining five layers are used for joint detection and tracking. These two decoders have the same structure but different inputs. The Detection Decoder $\\mathcal{D}_{det}$ takes the original learnable detect query $Q_{det}$", + "bbox": [ + 75, + 810, + 470, + 901 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "as input and generates the corresponding detect embedding $E_{det}^{t}$ , carrying enough semantic information to locate and classify the target roughly. After that, we concatenate the detect and track embedding together and feed them into the Joint Decoder $\\mathcal{D}_{joint}$ .", + "bbox": [ + 498, + 401, + 892, + 477 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.3. Long-Term Memory", + "text_level": 1, + "bbox": [ + 500, + 486, + 692, + 503 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Unlike previous methods [17, 42] that only exploit adjacent frames' information, we explicitly introduce a long-term memory $M_{tck}^{t}$ to maintain longer temporal information for tracked targets. When a newborn object is detected, we initialize its long-term memory with the current output.", + "bbox": [ + 496, + 508, + 890, + 585 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "It should be noted that in a video stream, objects only have minor deformation and movement in consecutive frames. Thus, we suppose the semantic feature of a tracked object changes only slightly in a short time. In the same way, our long-term memory should also update smoothly over time. Inspired by [28], we apply a simple but effective running average with exponentially decaying weights to update long-term memory $M_{tck}^{t}$ :", + "bbox": [ + 496, + 585, + 892, + 708 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\widetilde {M} _ {t c k} ^ {t + 1} = (1 - \\lambda) M _ {t c k} ^ {t} + \\lambda \\cdot O _ {t c k} ^ {t}, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 581, + 717, + 890, + 738 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\widetilde{M}_{tck}^{t+1}$ is the new long-term memory for the next frame. The memory update rate $\\lambda$ is experimentally set to 0.01, following the assumption that the memory changes smoothly and consistently in consecutive frames. We also tried some other values in Table 7.", + "bbox": [ + 496, + 744, + 890, + 821 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.4. Temporal Interaction Module", + "text_level": 1, + "bbox": [ + 500, + 832, + 764, + 848 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Adaptive Aggregation for Temporal Enhancement. Issues such as blurring or occlusion are often seen in a video stream. An intuitive idea to solve this problem is using", + "bbox": [ + 496, + 854, + 892, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "9903", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/e8cc905e439a8df8d2c700ebade1c23e6395f2327f99e183856078f055e73f54.jpg", + "image_caption": [ + "Figure 2. Illustration of Temporal Interaction Module. $\\widetilde{E}_{tck}^{t+1}$ and $\\widetilde{M}_{tck}^{t+1}$ are the prediction of $E_{tck}^{t}$ and $M_{tck}^{t}$ for the next frame, respectively." + ], + "image_footnote": [], + "bbox": [ + 140, + 88, + 406, + 300 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "multi-frame features to enhance the single-frame representation. Therefore, we fuse the outputs from two adjacent frames with an adaptive aggregation algorithm in our MeM-OTR. Due to occlusions and blurring, the output embedding $O_{tck}^{t}$ of the current frame may be unreliable. Thus, as illustrated in Figure 2, we generate a channel-wise weight $W_{tck}^{t}$ for each tracked instance to alleviate this problem:", + "bbox": [ + 75, + 383, + 467, + 489 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nW _ {t c k} ^ {t} = \\operatorname {S i g m o i d} \\left(\\operatorname {M L P} \\left(O _ {t c k} ^ {t}\\right)\\right). \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 165, + 505, + 468, + 523 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We multiply this weight $W_{tck}^{t}$ with the current output $O_{tck}^{t}$ and then concatenate the result with $O_{tck}^{t-1}$ from the previous frame. Furthermore, we apply a two-layer MLP to produce the fusion outcome $\\widetilde{O}_{tck}^{t}$ . This adaptive aggregation enhances the target representation with short-term temporal modeling.", + "bbox": [ + 75, + 529, + 468, + 619 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "However, we do not use the above channel-wise weight for previous output $O_{tck}^{t-1}$ . As we will discuss in Section 3.5, there is a difference between $O_{tck}^{t}$ and $O_{tck}^{t-1}$ . During inference, we employ a score threshold $\\tau_{tck}$ to guarantee that $O_{tck}^{t-1}$ is relatively reliable. Therefore, we input it entirely into the subsequent fusion step without the adaptive weight.", + "bbox": [ + 75, + 619, + 468, + 712 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Generate Track Embedding. As discussed in Section 3.1, we exploit the track embedding $E_{tck}^{t}$ to produce the location and category of each tracked target. Therefore, generating more reliable and distinguishable track embedding is the key to improving tracking performance. Our processing is illustrated in Figure 2.", + "bbox": [ + 75, + 719, + 468, + 808 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Since there are multiple similar objects in the same frame, we believe that learning more discriminative representations is also crucial to the tracker. Thus we employ a Multi-Head Attention [31] structure called memory-attention layer to achieve this interaction between different trajectories. Due to the reliability of long-term memory", + "bbox": [ + 75, + 810, + 468, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "$M_{tck}^{t}$ , we use it as $K$ , and the aggregation $\\hat{O}_{tck}^{t}$ and the output embedding $O_{tck}^{t}$ as $Q$ and $V$ , respectively.", + "bbox": [ + 498, + 89, + 890, + 121 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "After that, we combine long-term memory $M_{tck}^{t}$ and the result of memory-attention layer using addition, then input into an FFN network to predict the subsequent track embedding $\\widetilde{E}_{tck}^{t+1}$ . As shown in Equation (1), long-term memory is gradually changing over time. Therefore, by incorporating information from long-term memory, the track embedding $\\widetilde{E}_{tck}^{t+1}$ avoids abrupt changes that may cause association mistakes in consecutive frames. This design significantly improves the performance of object association, corroborated by ablation experiments shown in Table 6.", + "bbox": [ + 498, + 122, + 890, + 272 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.5. Inference Details", + "text_level": 1, + "bbox": [ + 500, + 282, + 666, + 296 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "At time step $t$ , we jointly input the learnable detect query $Q_{det}$ and track embedding $E_{tck}^{t}$ ( $E_{tck}^{0} = \\emptyset$ ) into our model to produce detection and tracking results, respectively. The detection result with a confidence score of more than $\\tau_{det}$ will transform into a newborn object.", + "bbox": [ + 498, + 306, + 890, + 381 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Target occlusion is a common issue in multi-object tracking task. If a tracked object is lost (confidence $\\leq \\tau_{tck}$ ) in the current frame, we do not directly remove its track embedding but mark it as inactive trajectory. Afterward, the inactive target will be removed entirely after $\\mathcal{T}_{miss}$ frames.", + "bbox": [ + 498, + 381, + 890, + 455 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "It is worth noting that we do not update the track embedding and long-term memory at every time step for each object. Instead, we choose to update those track embedding with high confidence. The choice of update threshold $\\tau_{next}$ yields the following formulation for updating:", + "bbox": [ + 498, + 458, + 890, + 532 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\left[ E _ {i} ^ {t + 1}, M _ {i} ^ {t + 1} \\right] = \\left\\{ \\begin{array}{l l} \\left[ \\widetilde {E} _ {i} ^ {t + 1}, \\widetilde {M} _ {i} ^ {t + 1} \\right], & c _ {i} ^ {t} > \\tau_ {\\text {n e x t}} \\\\ \\left[ E _ {i} ^ {t}, M _ {i} ^ {t} \\right], & c _ {i} ^ {t} \\leq \\tau_ {\\text {n e x t}} \\end{array} , \\right. \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 524, + 556, + 890, + 597 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $i$ is the target index, $t$ is the frame index, and $c_i^t$ is the predicted classification confidence of the $i^{th}$ object at time step $t$ . $\\widetilde{E}_i^{t + 1}$ and $\\widetilde{M}_i^{t + 1}$ are the predictions of track embedding and long-term memory, generated by Temporal Interaction Module shown in Figure 2. For simplicity, we set $\\tau_{det} = \\tau_{tck} = \\tau_{next} = 0.5$ in our experiments. $\\mathcal{T}_{miss}$ is set to 30, 15 and 10 on DanceTrack, MOT17 and BDD100K, respectively.", + "bbox": [ + 498, + 609, + 890, + 732 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 500, + 746, + 632, + 762 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Datasets and Metrics", + "text_level": 1, + "bbox": [ + 500, + 771, + 697, + 785 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Datasets. We mainly evaluate MeMOTR on the DanceTrack [29] dataset since they have more severe association challenges than traditional pedestrian tracking datasets. For a comprehensive evaluation, we also conduct experiments on MOT17 [23] and BDD100K [41].", + "bbox": [ + 498, + 794, + 890, + 869 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Metrics. Because of providing a balanced way to measure both detection and association performance explicitly,", + "bbox": [ + 498, + 869, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "9904", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "we use Higher Order Metric for Evaluating Multi-Object Tracking (HOTA) [21] to evaluate our method, especially analyzing our memory mechanism using Association Accuracy (AssA). We also list the MOTA [2] and IDF1 [25] metrics in our experimental results.", + "bbox": [ + 75, + 90, + 470, + 167 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Implementation Details", + "text_level": 1, + "bbox": [ + 76, + 176, + 294, + 193 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Following the settings in MOTR [42], we use several data augmentation methods, such as random resize and random crop. The shorter side of the input image is resized to 800, and the maximum size is restricted to 1536.", + "bbox": [ + 75, + 200, + 467, + 260 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We built MeMOTR upon DAB-Deformable-DETR [20] with a ResNet50 [15] backbone and initialize our model with the official DAB-Deformable-DETR [20] weights pretrained on the COCO [19] dataset. We suggest that the anchor-based position-prior from DAB-Deformable-DETR is quite effective due to the tracked box's smoothness in time and can be further exploited in future works. We also provide the results of our model based on Deformable-DETR [48] for fair comparison in Table 1. Our models are conducted on PyTorch with 8 NVIDIA Tesla V100 GPUs. By using PyTorch gradient checkpoint technology, we implement a memory-optimized version that can also be trained on NVIDIA GPUs with less than 10GB GPU memory. The batch size is set to 1 per GPU, and each batch contains a video clip with multiple frames. Within each clip, video frames are sampled with random intervals from 1 to 10. We use the AdamW optimizer with the initial learning rate of $2.0 \\times 10^{-4}$ . During training, we filter out the tracked target lower than the score threshold $\\tau_{update} = 0.5$ and IoU threshold $\\tau_{IoU} = 0.5$ .", + "bbox": [ + 75, + 261, + 468, + 563 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "On DanceTrack [29], we train MeMOTR for 18 epochs on the train set and drop the learning rate by a factor of 10 at the $12^{th}$ epoch. Firstly, we use two frames within a clip for training. And then increase the clip frames to 3, 4, and 5 at the $6^{th}$ , $10^{th}$ , and $14^{th}$ epochs, respectively. On MOT17 [23], due to the small train set (about 5K frames), it is easy to cause overfitting problems. Therefore, we add CrowdHuman [27] validation set to build a joint train set with MOT17 training data. CrowdHuman val set provides about 4K static images. Therefore, we apply random shifts from CenterTrack [46] to generate pseudo trajectories. Finally, we train MeMOTR for 130 epochs, and the learning rate decays by a factor of 10 at the $120^{th}$ epoch. The initial length of the training video clip is 2 and gradually increases to 3 and 4 at the $60^{th}$ and $100^{th}$ epochs, respectively. On BDD100K [41], we modify the sampling length at the $6^{th}$ and $10^{th}$ epochs and totally train 14 epochs while reducing the learning rate at the $12^{th}$ epoch.", + "bbox": [ + 75, + 564, + 468, + 835 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.3. Comparison on the DanceTrack Dataset", + "text_level": 1, + "bbox": [ + 76, + 845, + 419, + 862 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Since DanceTrack [29] is a dataset with various motions that cannot be modeled by classic linear motion estima", + "bbox": [ + 76, + 869, + 467, + 898 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/d808aeb85350d52c346e84e144656e0592fc4335415b902e2bd316092b86c74a.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodsHOTADetAAssAMOTAIDF1
w/o extra data:
FairMOT [44]39.766.723.882.240.8
CenterTrack [46]41.878.122.686.835.7
TraDeS [36]43.374.525.486.241.2
TransTrack [30]45.575.927.588.445.2
ByteTrack [43]47.771.032.189.653.9
GTR [47]48.072.531.984.750.3
QDTrack [24]54.280.136.887.750.4
MOTR [42]54.273.540.279.751.5
OC-SORT [5]55.180.338.392.054.6
C-BIoU [40]60.681.345.491.661.6
MeMOTR* (ours)63.477.052.385.465.5
MeMOTR (ours)68.580.558.489.971.2
with extra data:
MT_IoT [39]66.784.153.094.070.6
MOTRv2 [45]69.983.059.091.971.7
", + "bbox": [ + 519, + 89, + 874, + 349 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Table 1. Performance comparison with state-of-the-art methods on the DanceTrack [29] test set. Results for existing methods are from DanceTrack [29]. MeMOTR* means the result based on standard Deformable-DETR.", + "bbox": [ + 498, + 361, + 890, + 415 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "tion [3, 5], it provides a better choice to verify our tracking performance, especially the association performance.", + "bbox": [ + 498, + 440, + 890, + 470 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We compare MeMOTR with the state-of-the-art methods on the DanceTrack [29] test set in Table 1. Our method achieves 68.5 HOTA and gains a vast lead on the AssA metric (58.4 AssA), even surpassing some methods [39] that use additional datasets for training. Due to the limitations of the linear motion estimation module, some tracking-by-detection methods, for example, ByteTrack [43], although they can achieve great detection results (71.0 DetA), still cannot handle complex object association problems (32.1 AssA). However, their MOTA metrics are still high because MOTA overemphasizes detection performance.", + "bbox": [ + 496, + 470, + 890, + 637 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Our temporal interaction module, shown in Figure 2, leverages temporal information gracefully and efficiently. Moreover, the separated detection decoder $\\mathcal{D}_{det}$ discussed in Section 3.2 alleviates the conflicts between detection and tracking tasks. Therefore, we earn an impressive association performance (58.4 AssA and 71.2 IDF1) and competitive detection performance (80.5 DetA) compared with the state-of-the-art methods. We further prove our components' effectiveness in Section 4.6.", + "bbox": [ + 496, + 638, + 890, + 773 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.4. Comparison on the MOT17 Dataset", + "text_level": 1, + "bbox": [ + 500, + 785, + 808, + 800 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In order to make a comprehensive comparison, we also evaluate our method on the classic pedestrian tracking benchmark. Table 2 compares our method with state-of-the-art methods on the MOT17 [23] test set.", + "bbox": [ + 498, + 809, + 890, + 868 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Recent tracking-by-detection methods [40, 43] exploit robust detectors (like YOLOX [12]) to achieve really excel", + "bbox": [ + 500, + 869, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "9905", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/2f8180d156f524c649c4da7d569cc3746ea8b5dec0c3558a00c9bbff08c3d35f.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodsHOTADetAAssAMOTAIDF1
CNN based:
Tracktor++ [1]44.844.945.153.552.3
CenterTrack [46]52.253.851.067.864.7
TraDeS [36]52.755.250.869.163.9
QDTrack [24]53.955.652.768.766.3
GTR [47]59.161.657.075.371.5
FairMOT [44]59.360.958.073.772.3
DeepSORT [34]61.263.159.778.074.5
SORT [3]63.064.262.280.178.2
ByteTrack [43]63.164.562.080.377.3
Quo Vadis [10]63.164.662.180.377.7
OC-SORT [5]63.263.263.478.077.5
C-BIoU [40]64.164.863.781.179.7
Transformer based:
TrackFormer [22]///74.168.0
TransTrack [30]54.161.647.974.563.9
TransCenter [37]54.560.149.773.262.2
MeMOT [4]56.9/55.272.569.0
MOTR [42]57.258.955.871.968.4
MeMOTR (ours)58.859.658.472.871.5
Hybird based:
MOTRv2 [45]62.063.860.678.675.0
", + "bbox": [ + 98, + 89, + 450, + 440 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "lent detection performance (up to 64.8 DetA). Since performance on MOT17 overemphasizes detection performance, these methods perform immensely well. In this regard, there is still a massive gap in the detection performance of Transformer-based methods [4, 42] because too many dense and small object predictions are involved. In addition, the joint query in a shared Transformer decoder produces tracking and detection simultaneously, which may cause internal conflicts. The detect query is inhibited by the track query in the self-attention [31] structure, limiting the ability to detect newborn objects, especially those close to tracked targets, and vice versa. Because of this, TransTrack [30] achieves significantly better detection performance (61.6 DetA) due to its siamese network structure. This architecture decouples tracking and detection to resolve the above conflict, but its simple post-processing matching algorithm decreases its association performance.", + "bbox": [ + 75, + 535, + 468, + 792 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "On the other hand, we found that Transformer-based methods [42] suffer from serious overfitting problems in MOT17 [23] because of the tiny train set, which only contains about 5K frames. Although we use an additional CrowdHuman validation set for training mentioned in Section 4.2, severe overfitting still happens. Thus, we get $\\sim 90.0$ HOTA and $\\sim 95.0$ MOTA on the train set. However,", + "bbox": [ + 75, + 794, + 470, + 900 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/0a8ec96c5a0f804d6a8918a6596f445c89a282128fb6055b5096fe967315f037.jpg", + "table_caption": [ + "Table 2. Performance comparison with state-of-the-art methods on the MOT17 [23] test set. The best performance among the Transformer-based methods is marked in **bold. MOTRv2** [45] is marked in **hybrid** since their YOLOX [12] proposals." + ], + "table_footnote": [], + "table_body": "
MethodmTETAmHOTAmLocAmAssocAmAssA
QDTrack [24]47.8/45.948.5/
DeepSORT [34]48.0/46.446.7/
MOTR [42]50.737.035.851.047.3
TETer [18]50.8/47.252.9/
MeMOTR (ours)53.640.438.156.752.6
", + "bbox": [ + 504, + 89, + 887, + 191 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 3. Performance comparison on the BDD100K [41] val set. Results for existing methods are from [18].", + "bbox": [ + 500, + 200, + 890, + 229 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/797a29f04cbdbc905b218cf89a95352612119165dd8ad7231469aa95ba903aa4.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 529, + 244, + 694, + 329 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/a2b1f430ca88962de5828ac53574d1beb7f6f308c3a2747c5baedf5049c97f04.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 699, + 244, + 861, + 329 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/fd8abb219a02aed98c71c826320b4a221af423a51d3c18d6c95f4a611ab2f868.jpg", + "image_caption": [ + "Before Detection Decoder" + ], + "image_footnote": [], + "bbox": [ + 529, + 335, + 692, + 419 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/467bbfa2f84bb8895a042090eaa223f5d2c0f54019d1ee3ed1dac1fc0f84f55e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 699, + 335, + 861, + 419 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/7cb2c7bfe0255d3c493adec232ac55c337c4a8915eee4f5e6518c8b7f0317ee3.jpg", + "image_caption": [ + "After Detection Decoder", + "Figure 3. Visualize the anchors of tracked and newborn targets before (left) and after (right) the separated detection decoder $\\mathcal{D}_{\\text{det}}$ ." + ], + "image_footnote": [], + "bbox": [ + 535, + 436, + 857, + 457 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "too much additional training data can lead to inductive bias toward static people. Therefore, we argue that the train set of MOT17 is too small to train our model completely.", + "bbox": [ + 496, + 530, + 890, + 575 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Eventually, our method slightly improves the performance on the MOT17 test set to 58.8 HOTA. We gain competitive detection accuracy (DetA) compared with other Transformer-based methods. In particular, we improved the performance of object association, which AssA and IDF1 metrics can reflect. As a method that also uses the memory mechanism, our MeMOTR achieves higher AssA and IDF1, surpassing MeMOT [4] by $3.2\\%$ and $2.5\\%$ , respectively. These experimental results further validate the effectiveness of our method.", + "bbox": [ + 496, + 575, + 890, + 726 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.5. Comparison on the BDD100K Dataset", + "text_level": 1, + "bbox": [ + 500, + 739, + 828, + 755 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In order to evaluate our method in multi-category scenarios, we also evaluate our method on the BDD100K [41] val set in Table 3. To better assess multi-class tracking performance, we leverage Tracking-Every-Thing Accuracy (TETA) metric for ranking as they did in BDD100K MOT Challenge 2023. We re-evaluate MOTR [42] on the new metrics using the official model for comparison.", + "bbox": [ + 496, + 763, + 890, + 869 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The results show that our method can generalize well to multi-class scenarios and achieve impressive performance", + "bbox": [ + 498, + 869, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "9906", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/3d2fe92024c9107fe52b2176dd7dc9d68fbe5b63a42cb0b5fa94209bf8015a89.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
LDetHOTADetAAssAMOTAIDF1
062.174.352.283.165.6
163.974.655.083.467.1
263.273.854.381.965.8
", + "bbox": [ + 106, + 88, + 442, + 162 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/86e70dc4f9c6b232d2edef98ef02183e25a72cc0cc52181702c1ae6e62bb83a5.jpg", + "table_caption": [ + "Table 4. Ablation experiments on the layers of the separate Detection Decoder, which is denoted as $\\mathcal{L}_{\\mathcal{D}_{det}}$ ." + ], + "table_footnote": [], + "table_body": "
\\(O_{t-1}\\)\\(W_{tck}^{t}\\)HOTADetAAssAIDF1
62.373.952.764.6
✓62.474.552.564.6
✓62.774.453.165.3
✓✓63.974.655.067.1
", + "bbox": [ + 112, + 214, + 434, + 316 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "(53.6 TETA), especially in association (56.7 mAssocA), further demonstrating the effectiveness of our proposed method for associating targets.", + "bbox": [ + 76, + 366, + 468, + 412 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.6. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 422, + 230, + 438 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In this section, we study several components of our model, such as the long-term memory, adaptive aggregation, memory-attention layer, and separated detection decoder. Since our main contribution is a better utilization of temporal information, we choose to conduct ablation experiments on DanceTrack [29] due to its more severe object association challenges. On the other hand, DanceTrack [29] has more extensive training data to avoid severe overfitting (about $10 \\times$ compared with MOT17 [23]). We train our model on the train set and evaluate it on the official val set. Detection Decoder. For joint tracking and detection, the tracking-by-query paradigm processes detect and track queries in a shared Transformer decoder from scratch. However, the track query has rich semantic content from the previous tracked targets, in contrast to the object query for detection. On the other hand, learnable detect anchors often cover a larger range to find potential targets. In contrast, the anchor of tracked object pays more attention to a small area where the target appeared in the previous frame. This may cause a large gap between the anchors of tracked and newborn objects, as we visualized in Figure 3 (left).", + "bbox": [ + 75, + 446, + 468, + 763 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In this paper, we apply a separated Transformer decoder layer to perform preliminary target detection. The output $E_{det}^{t}$ of this Detection Decoder $\\mathcal{D}_{det}$ will be better aligned with the track embedding $E_{tck}^{t}$ generated by the previous frame to improve the tracking performance. We experimentally confirmed the effectiveness of this design, as shown in Table 4. Using only one separate Detection Decoder layer dramatically improves HOTA and AssA metrics by $1.8\\%$ and $2.8\\%$ , respectively. However, continuing to increase", + "bbox": [ + 75, + 763, + 470, + 901 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/03d075e878851d5cd94f563403fbefd3c05f085e1f48422a8d19b7ed27f2037e.jpg", + "table_caption": [ + "Table 5. Ablations on different designs of Adaptive Aggregation." + ], + "table_footnote": [], + "table_body": "
MtckattnHOTADetAAssAIDF1
naïve61.174.250.663.7
61.973.852.164.1
✓62.574.252.964.7
✓61.174.050.762.4
✓✓63.974.655.067.1
", + "bbox": [ + 539, + 88, + 857, + 210 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/ebb820529191996db3bf7b04c7591385dbf0c231419c14a6ad16227472d018d5.jpg", + "table_caption": [ + "Table 6. Ablation study of long-term memory $M_{tck}^{t}$ and memory-attention layer $attn$ . naive means a naive baseline with a single FFN for $O_{tck}^{t}$ to generate the track embedding $\\tilde{E}_{tck}^{t+1}$ ." + ], + "table_footnote": [], + "table_body": "
λHOTA↑DetA↑AssA↑IDF1↑IDsw ↓
0.00562.674.253.165.11383
0.0163.974.655.067.11237
0.0263.275.053.566.01213
0.0463.575.154.066.31295
", + "bbox": [ + 540, + 279, + 854, + 369 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 7. Ablation study on the long-term memory update ratio $\\lambda$ .", + "bbox": [ + 500, + 378, + 883, + 393 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "the layers of the Detection Decoder will reduce the refinement steps of track embeddings, thus slightly weakening the association performance. Furthermore, we visualize the bounding boxes after Detection Decoder in Figure 3 (right). This indicates that $\\mathcal{D}_{det}$ is able to locate objects roughly.", + "bbox": [ + 496, + 421, + 890, + 497 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Adaptive Aggregation. In Section 3.4, we design an adaptive aggregation, which dynamically fuses object features from adjacent frames. We ablate this structure in Table 5.", + "bbox": [ + 496, + 500, + 890, + 542 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "The first two results only use the current output $O_{tck}^{t}$ to generate the temporal aggregation $\\hat{O}_{tck}^{t}$ . In contrast, the next two lines fuse the previous output $\\hat{O}_{tck}^{t-1}$ into $\\hat{O}_{tck}^{t}$ . Introducing $O_{tck}^{t-1}$ provides additional object features from neighboring frames, thus improving tracking performance. We suppose this offers a complementary feature augmentation that can combat video ambiguity and uncertainty.", + "bbox": [ + 496, + 545, + 890, + 654 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Furthermore, we explore the impact of the dynamic weight $W_{tck}^{t}$ . As shown in Table 5, it only provides a little boost without $O_{tck}^{t-1}$ from the previous. We explain that dynamic $W_{tck}^{t}$ leads to missing information without complementary features from previous $O_{tck}^{t-1}$ . The result of the last row shows that utilizing both dynamic weight $W_{tck}^{t}$ and previous output $O_{tck}^{t-1}$ produces significantly better performance, with +2.6% HOTA and +2.3% AssA.", + "bbox": [ + 496, + 655, + 890, + 776 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Long-Term Memory. We propose a long-term memory in Section 3.3 to utilize longer temporal information and further inject it into subsequent track embedding to augment the object feature.", + "bbox": [ + 496, + 777, + 890, + 838 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We explore the impact of long-term memory $M_{tck}^{t}$ and show the experimental results in Table 6. For a more comprehensive comparison, we also experiment with another track embedding generation structure that removes the", + "bbox": [ + 496, + 839, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "9907", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/06118ad33e3e8445367062471ca789139ee714e0b0fdfeb9ed50bc90a851222b.jpg", + "image_caption": [ + "(a) w/o memory and w/o attention" + ], + "image_footnote": [], + "bbox": [ + 86, + 98, + 272, + 242 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/2c7aae48cfcd35add5b9787e25e8286df7947cae899639cf622a7857fb5224d5.jpg", + "image_caption": [ + "(b) $w / o$ memory and $w/$ attention" + ], + "image_footnote": [], + "bbox": [ + 287, + 98, + 475, + 242 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/b98afde71d03efafd8f3551aed53ec0ef612be966c2fc82c8707abc18c42c986.jpg", + "image_caption": [ + "(c) $w/$ memory and $w/o$ attention", + "Figure 4. Visualization of Track Embedding $E_{tck}^{t}$ (the first 50 frames in sequence dancetrack0063) from different structure designs by using t-Distributed Stochastic Neighbor Embedding (t-SNE). Track embeddings for different tracked targets (IDs) are marked in different colors and shapes. Our design 4(d) helps the model learn a more stable and distinguishable representation for the track embedding. Corresponding tracking performance is shown in Table 6." + ], + "image_footnote": [], + "bbox": [ + 490, + 98, + 678, + 242 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/abc8835bc4f651d8b33671732b4adaac2cab12ea9a9aa987e80c6612f1a58049.jpg", + "image_caption": [ + "(d) $w/$ memory and $w/$ attention (ours)" + ], + "image_footnote": [], + "bbox": [ + 692, + 98, + 880, + 242 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "memory-attention layer by passing the temporal aggregation $\\hat{O}_{tck}^{t}$ directly to an FFN network.", + "bbox": [ + 75, + 349, + 467, + 380 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Our experimental results show that utilizing long-term memory produces a better association performance, with $+0.8\\%$ and $+4.3\\%$ AssA for w/o and w/ memory-attention layer. The injection of long-term memory significantly stabilizes and augments the identity information of each track embedding, as visualized in Figure 4(c) and 4(d).", + "bbox": [ + 75, + 380, + 468, + 470 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Memory Attention. In Table 6, we also ablate memory-attention layer. It shows that by using memory-attention layer, our MeMOTR achieves much better performance (63.9 vs. 62.5 HOTA), especially improving AssA by $2.1\\%$ . This attention layer establishes interactions between different trajectories that help the track embedding learns discriminative features. However, without long-term memory $M_{tck}^{t}$ , memory-attention layer produces worse performance $(-1.4\\%)$ AssA and $-1.7\\%$ IDF1. We explain that the track embedding without memory augmentation is unstable. Therefore, interacting with such unreliable information can be counterproductive, as visualized in Figure 4(b).", + "bbox": [ + 75, + 472, + 468, + 652 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Memory Update Rate. Here, we explored the impact of long-term memory update rate $\\lambda$ on the tracking performance in Equation 1. As shown in Table 7, when progressively increasing the $\\lambda_{L}$ from 0.005 to 0.04, our model achieves the highest HOTA score at $\\lambda = 0.01$ while DetA score is decreasing slightly. We suggest the update rate $\\lambda$ may be a hyperparameter that needs to be chosen according to different datasets. For example, scenarios with plenty of target non-rigid deformation may need a higher memory update rate to adapt to the rapidly changing features.", + "bbox": [ + 75, + 652, + 468, + 804 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.7. Limitations", + "text_level": 1, + "bbox": [ + 76, + 816, + 202, + 830 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Although our MeMOTR brings a significant improvement in association performance, detection performance is still a drawback, especially in crowded scenarios (like MOT17 [23]). During experiments, we observed that some", + "bbox": [ + 75, + 839, + 468, + 900 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "times newborn objects are suppressed by tracked targets in the self-attention structure, which leads to reduced detection performance. Therefore, resolving this conflict is a crucial challenge for the joint tracking paradigm. This may help improve the detection capabilities, which can boost the overall tracking performance of the model, as studied in [45]. In addition, in pedestrian tracking, existing datasets are still limited in size and diversity. We suggest that training with other simulation datasets (like MOTSynth [11]) may alleviate the overfitting problem of our model and achieve better tracking performance.", + "bbox": [ + 496, + 349, + 890, + 515 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 537, + 617, + 551 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We have proposed MeMOTR, an end-to-end long-term memory-augmented Transformer for multi-object tracking. Our method builds a stable long-term memory for each tracked object and exploits this memory to augment the representation of track embedding, thus improving its association performance. Furthermore, by leveraging a memory-attention layer, our model makes different targets more distinguishable. As a result, our approach achieves the state-of-the-art performance on MOT benchmarks, especially in scenes with irregular motion patterns. Extensive ablation experiments and visualizations demonstrate the effectiveness of our components. We hope that future work will pay more attention to the use of long-term temporal information for object tracking.", + "bbox": [ + 496, + 566, + 890, + 776 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgements. This work is supported by National Key R&D Program of China (No. 2022ZD0160900), National Natural Science Foundation of China (No. 62076119, No. 61921006), Fundamental Research Funds for the Central Universities (No. 020214380091, No. 020214380099), and Collaborative Innovation Center of Novel Software Technology and Industrialization. Besides, Ruopeng Gao would like to thank Muyan Yang for her social support.", + "bbox": [ + 496, + 779, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "9908", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Philipp Bergmann, Tim Meinhardt, and Laura Leal-Taixe. Tracking without bells and whistles. In ICCV, pages 941-951. IEEE, 2019. 6", + "[2] Keni Bernstein and Rainer Stiefelhagen. Evaluating multiple object tracking performance: The CLEAR MOT metrics. EURASIP J. Image Video Process., 2008, 2008. 5", + "[3] Alex Bewley, ZongYuan Ge, Lionel Ott, Fabio Tozeto Ramos, and Ben Upcroft. Simple online and realtime tracking. In ICIP, pages 3464-3468. IEEE, 2016. 1, 2, 5, 6", + "[4] Jiarui Cai, Mingze Xu, Wei Li, Yuanjun Xiong, Wei Xia, Zhuowen Tu, and Stefano Soatto. Memot: Multi-object tracking with memory. In CVPR, pages 8080-8090. IEEE, 2022. 2, 6", + "[5] Jinkun Cao, Xinshuo Weng, Rawal Khirodkar, Jiangmiao Pang, and Kris Kitani. Observation-centric SORT: rethinking SORT for robust multi-object tracking. CoRR, abs/2203.14360, 2022. 1, 2, 5, 6", + "[6] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In ECCV(1), volume 12346 of Lecture Notes in Computer Science, pages 213-229. Springer, 2020. 2, 3", + "[7] Wongun Choi and Silvio Savarese. A unified framework for multi-target tracking and collective activity recognition. In ECCV (4), volume 7575 of Lecture Notes in Computer Science, pages 215-230. Springer, 2012. 1", + "[8] Yutao Cui, Chenkai Zeng, Xiaoyu Zhao, Yichun Yang, Gangshan Wu, and Limin Wang. SportsMOT: A large multi-object tracking dataset in multiple sports scenes. In ICCV, 2023. 1", + "[9] Patrick Dendorfer, Hamid Rezatofighi, Anton Milan, Javen Shi, Daniel Cremers, Ian D. Reid, Stefan Roth, Konrad Schindler, and Laura Leal-Taixe. MOT20: A benchmark for multi object tracking in crowded scenes. CoRR, abs/2003.09003, 2020. 2", + "[10] Patrick Dendorfer, Vladimir Yugay, Aljosa Osep, and Laura Leal-Taixe. Quo vadis: Is trajectory forecasting the key towards long-term multi-object tracking? In NeurIPS, 2022. 2, 6", + "[11] Matteo Fabbri, Guillem Brasó, Gianluca Maugeri, Orcun Cetintas, Riccardo Gasparini, Aljosa Osep, Simone Calderara, Laura Leal-Taixe, and Rita Cucchiara. Motsynth: How can synthetic data help pedestrian detection and tracking? In ICCV, pages 10829-10839. IEEE, 2021. 8", + "[12] Zheng Ge, Songtao Liu, Feng Wang, Zeming Li, and Jian Sun. YOLOX: exceeding YOLO series in 2021. CoRR, abs/2107.08430, 2021. 1, 2, 5, 6", + "[13] Silvio Giancola, Mohieddine Amine, Tarek Dghaily, and Bernard Ghanem. Socernet: A scalable dataset for action spotting in soccer videos. In CVPR Workshops, pages 1711-1721. Computer Vision Foundation / IEEE Computer Society, 2018. 1", + "[14] Agrim Gupta, Justin Johnson, Li Fei-Fei, Silvio Savarese, and Alexandre Alahi. Social GAN: socially acceptable trajectories with generative adversarial networks. In CVPR," + ], + "bbox": [ + 78, + 114, + 468, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "pages 2255-2264. Computer Vision Foundation / IEEE Computer Society, 2018. 2", + "[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778. IEEE Computer Society, 2016. 2, 3, 5", + "[16] Weiming Hu, Tieniu Tan, Liang Wang, and Stephen J. Maybank. A survey on visual surveillance of object motion and behaviors. IEEE Trans. Syst. Man Cybern. Part C, 34(3):334-352, 2004. 1", + "[17] Bruno Korbar and Andrew Zisserman. End-to-end tracking with a multi-query transformer. CoRR, abs/2210.14601, 2022. 2, 3", + "[18] Siyuan Li, Martin Danelljan, Henghui Ding, Thomas E. Huang, and Fisher Yu. Tracking every thing in the wild. In ECCV (22), volume 13682 of Lecture Notes in Computer Science, pages 498-515. Springer, 2022. 6", + "[19] Tsung-Yi Lin, Michael Maire, Serge J. Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C. Lawrence Zitnick. Microsoft COCO: common objects in context. In ECCV (5), volume 8693 of Lecture Notes in Computer Science, pages 740-755. Springer, 2014. 5", + "[20] Shilong Liu, Feng Li, Hao Zhang, Xiao Yang, Xianbiao Qi, Hang Su, Jun Zhu, and Lei Zhang. DAB-DETR: dynamic anchor boxes are better queries for DETR. In ICLR. OpenReview.net, 2022. 3, 5", + "[21] Jonathon Luiten, Aljosa Osep, Patrick Dendorfer, Philip H. S. Torr, Andreas Geiger, Laura Leal-Taixe, and Bastian Leibe. HOTA: A higher order metric for evaluating multi-object tracking. Int. J. Comput. Vis., 129(2):548-578, 2021. 5", + "[22] Tim Meinhardt, Alexander Kirillov, Laura Leal-Taixe, and Christoph Feichtenhofer. Trackformer: Multi-object tracking with transformers. In CVPR, pages 8834-8844. IEEE, 2022. 1, 2, 3, 6", + "[23] Anton Milan, Laura Leal-Taixe, Ian D. Reid, Stefan Roth, and Konrad Schindler. MOT16: A benchmark for multi-object tracking. CoRR, abs/1603.00831, 2016. 1, 2, 4, 5, 6, 7, 8", + "[24] Jiangmiao Pang, Linlu Qiu, Xia Li, Haofeng Chen, Qi Li, Trevor Darrell, and Fisher Yu. Quasi-dense similarity learning for multiple object tracking. In CVPR, pages 164-173. Computer Vision Foundation / IEEE, 2021. 5, 6", + "[25] Ergys Ristani, Francesco Solera, Roger S. Zou, Rita Cucchiara, and Carlo Tomasi. Performance measures and a data set for multi-target, multi-camera tracking. In ECCV Workshops (2), volume 9914 of Lecture Notes in Computer Science, pages 17-35, 2016. 5", + "[26] Ergys Ristani and Carlo Tomasi. Features for multi-target multi-camera tracking and re-identification. In CVPR, pages 6036–6046. Computer Vision Foundation / IEEE Computer Society, 2018. 1", + "[27] Shuai Shao, Zijian Zhao, Boxun Li, Tete Xiao, Gang Yu, Xiangyu Zhang, and Jian Sun. Crowdhuman: A benchmark for detecting human in a crowd. CoRR, abs/1805.00123, 2018. 5", + "[28] Chris Stauffer and W. Eric L. Grimson. Adaptive background mixture models for real-time tracking. In CVPR, pages 2246-2252. IEEE Computer Society, 1999. 1, 3" + ], + "bbox": [ + 503, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "9909", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[29] Peize Sun, Jinkun Cao, Yi Jiang, Zehuan Yuan, Song Bai, Kris Kitani, and Ping Luo. Dancetrack: Multi-object tracking in uniform appearance and diverse motion. In CVPR, pages 20961-20970. IEEE, 2022. 1, 2, 4, 5, 7", + "[30] Peize Sun, Yi Jiang, Rufeng Zhang, Enze Xie, Jinkun Cao, Xinting Hu, Tao Kong, Zehuan Yuan, Changhu Wang, and Ping Luo. Transtrack: Multiple-object tracking with transformer. CoRR, abs/2012.15460, 2020. 2, 5, 6", + "[31] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In NIPS, pages 5998-6008, 2017. 3, 4, 6", + "[32] Zhongdao Wang, Liang Zheng, Yixuan Liu, Yali Li, and Shengjin Wang. Towards real-time multi-object tracking. In ECCV (11), volume 12356 of Lecture Notes in Computer Science, pages 107-122. Springer, 2020. 1, 2", + "[33] Greg Welch, Gary Bishop, et al. An introduction to the kalman filter. 1995. 2", + "[34] Nicolai Wojke, Alex Bewley, and Dietrich Paulus. Simple online and realtime tracking with a deep association metric. In ICIP, pages 3645-3649. IEEE, 2017. 2, 6", + "[35] Sanghyun Woo, Kwanyong Park, Seoul Wug Oh, In So Kweon, and Joon-Young Lee. Tracking by associating clips. In ECCV (25), volume 13685 of Lecture Notes in Computer Science, pages 129–145. Springer, 2022. 2", + "[36] Jialian Wu, Jiale Cao, Liangchen Song, Yu Wang, Ming Yang, and Junsong Yuan. Track to detect and segment: An online multi-object tracker. In CVPR, pages 12352-12361. Computer Vision Foundation / IEEE, 2021. 5, 6", + "[37] Yihong Xu, Yutong Ban, Guillaume Delorme, Chuang Gan, Daniela Rus, and Xavier Alameda-Pineda. Transcenter: Transformers with dense queries for multiple-object tracking. CoRR, abs/2103.15145, 2021. 6", + "[38] Bin Yan, Yi Jiang, Peize Sun, Dong Wang, Zehuan Yuan, Ping Luo, and Huchuan Lu. Towards grand unification of object tracking. In ECCV (21), volume 13681 of Lecture Notes in Computer Science, pages 733-751. Springer, 2022. 2", + "[39] Feng Yan, Zhiheng Li, Weixin Luo, Zequn jie, Fan Liang, Xiaolin Wei, and Lin Ma. Multiple object tracking challenge technical report for team mt_iot, 2022. 5", + "[40] Fan Yang, Shigeyuki Odashima, Shoichi Masui, and Shan Jiang. Hard to track objects with irregular motions and similar appearances? make it easier by buffering the matching space. In WACV, pages 4788-4797. IEEE, 2023. 1, 5, 6", + "[41] Fisher Yu, Haofeng Chen, Xin Wang, Wenqi Xian, Yingying Chen, Fangchen Liu, Vashisht Madhavan, and Trevor Darrell. BDD100K: A diverse driving dataset for heterogeneous multitask learning. In CVPR, pages 2633-2642. Computer Vision Foundation / IEEE, 2020. 2, 4, 5, 6", + "[42] Fangao Zeng, Bin Dong, Yuang Zhang, Tiancai Wang, Xi-angyu Zhang, and Yichen Wei. MOTR: end-to-end multiple-object tracking with transformer. In ECCV (27), volume 13687 of Lecture Notes in Computer Science, pages 659–675. Springer, 2022. 1, 2, 3, 5, 6", + "[43] Yifu Zhang, Peize Sun, Yi Jiang, Dongdong Yu, Fucheng Weng, Zehuan Yuan, Ping Luo, Wenyu Liu, and Xinggang" + ], + "bbox": [ + 78, + 90, + 470, + 902 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Wang. Bytetrack: Multi-object tracking by associating every detection box. In ECCV (22), volume 13682 of Lecture Notes in Computer Science, pages 1-21. Springer, 2022. 1, 2, 5, 6", + "[44] Yifu Zhang, Chunyu Wang, Xinggang Wang, Wenjun Zeng, and Wenyu Liu. Fairmot: On the fairness of detection and re-identification in multiple object tracking. Int. J. Comput. Vis., 129(11):3069-3087, 2021. 2, 5, 6", + "[45] Yang Zhang, Tiancai Wang, and Xiangyu Zhang. Motrv2: Bootstrapping end-to-end multi-object tracking by pretrained object detectors, 2022. 5, 6, 8", + "[46] Xingyi Zhou, Vladlen Koltun, and Philipp Krahenbuhl. Tracking objects as points. In ECCV (4), volume 12349 of Lecture Notes in Computer Science, pages 474-490. Springer, 2020. 5, 6", + "[47] Xingyi Zhou, Tianwei Yin, Vladlen Koltun, and Philipp Krahenbihl. Global tracking transformers. In CVPR, pages 8761-8770. IEEE, 2022. 2, 5, 6", + "[48] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable DETR: deformable transformers for end-to-end object detection. In ICLR. OpenReview.net, 2021. 5" + ], + "bbox": [ + 501, + 92, + 890, + 387 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "9910", + "bbox": [ + 482, + 944, + 516, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/40deaafe-8b86-4716-a18c-f883acf32105_model.json b/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/40deaafe-8b86-4716-a18c-f883acf32105_model.json new file mode 100644 index 0000000000000000000000000000000000000000..69f77c80055eb2b7f1a20e3de3f585b0571134db --- /dev/null +++ b/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/40deaafe-8b86-4716-a18c-f883acf32105_model.json @@ -0,0 +1,2211 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.194, + 0.131, + 0.78, + 0.177 + ], + "angle": 0, + "content": "MeMOTR: Long-Term Memory-Augmented Transformer for Multi-Object Tracking" + }, + { + "type": "text", + "bbox": [ + 0.318, + 0.204, + 0.652, + 0.222 + ], + "angle": 0, + "content": "Ruopeng Gao\\(^{1}\\) Limin Wang\\(^{1,2,\\text{四}}\\)" + }, + { + "type": "text", + "bbox": [ + 0.107, + 0.221, + 0.865, + 0.24 + ], + "angle": 0, + "content": "\\(^{1}\\)State Key Laboratory for Novel Software Technology, Nanjing University \\(^{2}\\)Shanghai AI Lab" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.289, + 0.314, + 0.306 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.321, + 0.474, + 0.594 + ], + "angle": 0, + "content": "As a video task, Multiple Object Tracking (MOT) is expected to capture temporal information of targets effectively. Unfortunately, most existing methods only explicitly exploit the object features between adjacent frames, while lacking the capacity to model long-term temporal information. In this paper, we propose MeMOTR, a long-term memory-augmented Transformer for multi-object tracking. Our method is able to make the same object's track embedding more stable and distinguishable by leveraging long-term memory injection with a customized memory-attention layer. This significantly improves the target association ability of our model. Experimental results on DanceTrack show that MeMOTR impressively surpasses the state-of-the-art method by \\(7.9\\%\\) and \\(13.0\\%\\) on HOTA and AssA metrics, respectively. Furthermore, our model also outperforms other Transformer-based methods on association performance on MOT17 and generalizes well on BDD100K. Code is available at https://github.com/MCG-NJU/MeMOTR." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.624, + 0.21, + 0.64 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.649, + 0.47, + 0.74 + ], + "angle": 0, + "content": "Multi-Object Tracking (MOT) [8, 23, 29] aims to detect multiple objects and maintain their identities in a video stream. MOT can be applied to numerous downstream tasks, such as action recognition [7], behavior analysis [16], and so on. It is also an important technique for real-world applications, e.g., autonomous driving and surveillance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.741, + 0.471, + 0.878 + ], + "angle": 0, + "content": "According to the definition of MOT, this task can be formally divided into two parts: object detection and association. For a long time, pedestrian tracking datasets (like MOT17 [23]) have had mainstream domination in the community. However, these datasets have insufficient challenges in target association because of their almost linear motion pattern. Therefore, tracking-by-detection methods [5, 32, 43] achieve the state-of-the-art performance of MOT for several years. They first adopt a robust object de" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.276, + 0.895, + 0.487 + ], + "angle": 0, + "content": "tector (e.g., YOLOX [12]) to independently localize the objects in each frame and associate them with IoU [3, 40] or ReID features [26]. However, associating targets becomes a critical challenge in some complex scenarios, like group dancers [29] and sports players [8, 13]. These similar appearances and erratic movements may cause existing methods to fail. Recently, Transformer-based tracking methods [22, 42] have introduced a new fully-end-to-end MOT paradigm. Through the interaction and progressive decoding of detect and track queries in Transformer, they simultaneously complete detection and tracking. This paradigm is expected to have greater potential for object association due to the flexibility of Transformer, especially in the above complex scenes." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.489, + 0.896, + 0.656 + ], + "angle": 0, + "content": "Although these Transformer-based methods achieve excellent performance, they still struggle with some complicated issues, such as analogous appearances, irregular motion patterns, and long-term occlusions. We hypothesize that more intelligent leverage of temporal information can provide the tracker a more effective and robust representation for each tracked target, thereby relieving the above issues and boosting the tracking performance. Unfortunately, most previous methods [22, 42] only exploit the image or object features between two adjacent frames, which lacking the utilization of long-term temporal information." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.657, + 0.897, + 0.884 + ], + "angle": 0, + "content": "Based on the analysis above, in this paper, we focus on leveraging temporal information by proposing a long-term Memory-augmented Multi-Object Tracking method with TRansformer, coined as MeMOTR. We exploit detect and track embeddings to localize newborn and tracked objects via a Transformer Decoder, respectively. Our model maintains a long-term memory with the exponential recursion update algorithm [28] for each tracked object. Afterward, we inject this memory into the track embedding, reducing its abrupt changes and thus improving the model association ability. As multiple tracked targets exist in a video stream, we apply a memory-attention layer to produce a more distinguishable representation. Besides, we present an adaptive aggregation to fuse the object feature from two adjacent frames to improve tracking robustness." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.886, + 0.892, + 0.902 + ], + "angle": 0, + "content": "In addition, we argue that the learnable detection query" + }, + { + "type": "page_footnote", + "bbox": [ + 0.1, + 0.888, + 0.366, + 0.901 + ], + "angle": 0, + "content": "\\(\\boxtimes\\) : Corresponding author (lmwang@nju.edu.cn)." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "9901" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.242 + ], + "angle": 0, + "content": "in DETR [6] has no semantic information about specific objects. However, the track query in Transformer-based MOT methods like MOTR [42] carries information about a tracked object. This difference will cause a semantic information gap and thus degrade the final tracking performance. Therefore, to overcome this issue, we use a light decoder to perform preliminary object detection, which outputs the detect embedding with specific semantics. Then we jointly input detect and track embeddings into the subsequent decoder to make MeMOTR tracking results more precise." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.243, + 0.471, + 0.395 + ], + "angle": 0, + "content": "We mainly evaluate our method on the DanceTrack dataset [29] because of its serious association challenge. Experimental results show that our method achieves the state-of-the-art performance on this challenging DanceTrack dataset, especially on association metrics (e.g., AssA, IDF1). We also evaluate our model on the traditional pedestrian tracking dataset of MOT17 [23] and the multicategories tracking dataset of BDD100K [41]. In addition, we perform extensive ablation studies further demonstrate the effectiveness of our designs." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.408, + 0.22, + 0.423 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.432, + 0.47, + 0.493 + ], + "angle": 0, + "content": "Tracking-by-Detection is a widely used MOT paradigm that has recently dominated the community. These methods always get trajectories by associating a given set of detections in a streaming video." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.493, + 0.471, + 0.81 + ], + "angle": 0, + "content": "The objects in classic pedestrian tracking scenarios [9, 23] always have different appearances and regular motion patterns. Therefore, appearance matching and linear motion estimation are widely used to match targets in consecutive frames. SORT [3] uses the Intersection-over-Union (IoU) to match predictions of the Kalman filter [33] and detected boxes. Deep-SORT [34] applies an additional network to extract target features, then utilizes cosine distances for matching besides motion consideration in SORT [3]. JDE [32], FairMOT [44], and Unicorn [38] further explore the architecture of appearance embedding and matching. ByteTrack [43] employs a robust detector based onYOLOX [12] and reuses low-confidence detections to enhance the association ability. Furthermore, OC-SORT [5] improves SORT [3] by rehabilitating lost targets. In recent years, as a trendy framework in vision tasks, some studies [35, 47] have also applied Transformers to match detection bounding boxes. Moreover, Dendorfer et al. [10] attempt to model pedestrian trajectories by leveraging more complex motion estimation methods (like S-GAN [14]) from the trajectory prediction task." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.47, + 0.903 + ], + "angle": 0, + "content": "The methods described above have powerful detection capabilities due to their robust detectors. However, although such methods have achieved outstanding performance in pedestrian tracking datasets, they are mediocre at dealing with more complex scenarios having irregular movements. These unforeseeable motion patterns will cause the trajec" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.8, + 0.107 + ], + "angle": 0, + "content": "tory estimation and prediction module to fail." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.108, + 0.892, + 0.184 + ], + "angle": 0, + "content": "Tracking-by-Query usually does not require additional post-processing to associate detection results. Unlike the tracking-by-detection paradigm mentioned above, tracking-by-query methods apply the track query to decode the location of tracked objects progressively." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.184, + 0.893, + 0.426 + ], + "angle": 0, + "content": "Inspired by DETR-family [6], most of these methods [22, 42] leverage the learnable object query to perform newborn object detection, while the track query localizes the position of tracked objects. TransTrack [30] builds a siamese network for detection and tracking, then applies an IoU matching to produce newborn targets. TrackFormer [22] utilizes the same Transformer decoder for both detection and tracking, then employs a nonmaximum suppression (NMS) with a high IoU threshold to remove strongly overlapping duplicate bounding boxes. MOTR [42] builds an elegant and fully end-to-end Transformer for multi-object tracking. This paradigm performs excellently in dealing with irregular movements due to the flexibility of query-based design. Furthermore, MQT [17] employs different queries to represent one tracked object and cares more about class-agnostic tracking." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.427, + 0.894, + 0.609 + ], + "angle": 0, + "content": "However, current query-based methods typically exploit the information of adjacent frames (query [42] or feature [22] fusion). Although the track query can be continuously updated over time, most methods still do not explicitly exploit longer temporal information. Cai et al. [4] explore a large memory bank to benefit from time-related knowledge but suffer enormous storage costs. In order to use long-term information, we propose a long-term memory to stabilize the tracked object feature over time and a memory-attention layer for a more distinguishable representation. Our experiments further approve that this approach significantly improves association performance in MOT." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.624, + 0.593, + 0.64 + ], + "angle": 0, + "content": "3. Method" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.649, + 0.61, + 0.664 + ], + "angle": 0, + "content": "3.1. Overview" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.674, + 0.892, + 0.809 + ], + "angle": 0, + "content": "We propose the MeMOTR, a long-term memory-augmented Transformer for multi-object tracking. Different from most existing methods [22, 42] that only explicitly utilize the states of tracked objects between adjacent frames, our core contribution is to build a long-term memory (in Section 3.3) that maintains the long-term temporal feature for each tracked target, together with a temporal interaction module (TIM) that effectively injects the temporal information into subsequent tracking processes." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Like most DETR-family methods [6], we use a ResNet-50 [15] backbone and a Transformer Encoder to produce the image feature of an input frame \\(I^t\\). As shown in Figure 1, the learnable detect query \\(Q_{det}\\) is fed into the Detection Decoder \\(\\mathcal{D}_{det}\\) (in Section 3.2) to generate the detect embedding \\(E_{det}^{t}\\) for the current frame. Afterward, by query" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "9902" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.088, + 0.094, + 0.885, + 0.279 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.293, + 0.893, + 0.378 + ], + "angle": 0, + "content": "Figure 1. Overview of MeMOTR. Like most DETR-based [6] methods, we exploit a ResNet-50 [15] backbone and a Transformer [31] Encoder to learn a 2D representation of an input image. We use different colors to indicate different tracked targets, and the learnable detect query \\( Q_{det} \\) is illustrated in gray. Then the Detection Decoder \\( \\mathcal{D}_{det} \\) processes the detect query to generate the detect embedding \\( E_{det}^{t} \\), which aligns with the track embedding \\( E_{tck}^{t} \\) from previous frames. Long-term memory is denoted as \\( M_{tck}^{t} \\). The initialization process in the blue dotted arrow will be applied to newborn objects. Our Long-Term Memory and Temporal Interaction Module is discussed in Section 3.3 and 3.4. More details are illustrated in Figure 2." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.401, + 0.473, + 0.588 + ], + "angle": 0, + "content": "ing the encoded image feature with \\([E_{det}^{t}, E_{tck}^{t}]\\), the Transformer Joint Decoder \\(\\mathcal{D}_{joint}\\) produces the corresponding output \\([\\hat{O}_{det}^{t}, \\hat{O}_{tck}^{t}]\\). For simplicity, we merge the newborn objects in \\(\\hat{O}_{det}^{t}\\) (yellow box) with tracked objects' output \\(\\hat{O}_{tck}^{t}\\), denoted by \\(O_{tck}^{t}\\). Afterward, we predict the classification confidence \\(c_{i}^{t}\\) and bounding box \\(b_{i}^{t}\\) corresponding to the \\(i^{th}\\) target from the output embeddings. Finally, we feed the output from adjacent frames \\([O_{tck}^{t}, O_{tck}^{t-1}]\\) and the long-term memory \\(M_{tck}^{t}\\) into the Temporal Interaction Module, updating the subsequent track embedding \\(E_{tck}^{t+1}\\) and long-term memory \\(M_{tck}^{t+1}\\). The details of our components will be elaborated in the following sections." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.603, + 0.255, + 0.617 + ], + "angle": 0, + "content": "3.2. Detection Decoder" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.628, + 0.47, + 0.809 + ], + "angle": 0, + "content": "In the previous Transformer-based methods [22, 42], the learnable detect query and the previous track query are jointly input to Transformer Decoder from scratch. This simple idea extends the end-to-end detection Transformer [6] to multi-object tracking. Nonetheless, we argue that this design may cause misalignment between detect and track queries. As discussed in numerous works [6, 20], the learnable object query in DETR-family plays a role similar to a learnable anchor with little semantic information. On the other hand, track queries have specific semantic knowledge to resolve their category and bounding boxes since they are generated from the output of previous frames." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Therefore, as illustrated in Figure 1, we split the original Transformer Decoder into two parts. The first decoder layer is used for detection, and the remaining five layers are used for joint detection and tracking. These two decoders have the same structure but different inputs. The Detection Decoder \\(\\mathcal{D}_{det}\\) takes the original learnable detect query \\(Q_{det}\\)" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.402, + 0.893, + 0.478 + ], + "angle": 0, + "content": "as input and generates the corresponding detect embedding \\( E_{det}^{t} \\), carrying enough semantic information to locate and classify the target roughly. After that, we concatenate the detect and track embedding together and feed them into the Joint Decoder \\( \\mathcal{D}_{joint} \\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.487, + 0.694, + 0.504 + ], + "angle": 0, + "content": "3.3. Long-Term Memory" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.51, + 0.892, + 0.586 + ], + "angle": 0, + "content": "Unlike previous methods [17, 42] that only exploit adjacent frames' information, we explicitly introduce a long-term memory \\( M_{tck}^{t} \\) to maintain longer temporal information for tracked targets. When a newborn object is detected, we initialize its long-term memory with the current output." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.586, + 0.893, + 0.709 + ], + "angle": 0, + "content": "It should be noted that in a video stream, objects only have minor deformation and movement in consecutive frames. Thus, we suppose the semantic feature of a tracked object changes only slightly in a short time. In the same way, our long-term memory should also update smoothly over time. Inspired by [28], we apply a simple but effective running average with exponentially decaying weights to update long-term memory \\( M_{tck}^{t} \\):" + }, + { + "type": "equation", + "bbox": [ + 0.582, + 0.718, + 0.892, + 0.739 + ], + "angle": 0, + "content": "\\[\n\\widetilde {M} _ {t c k} ^ {t + 1} = (1 - \\lambda) M _ {t c k} ^ {t} + \\lambda \\cdot O _ {t c k} ^ {t}, \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.746, + 0.892, + 0.822 + ], + "angle": 0, + "content": "where \\(\\widetilde{M}_{tck}^{t+1}\\) is the new long-term memory for the next frame. The memory update rate \\(\\lambda\\) is experimentally set to 0.01, following the assumption that the memory changes smoothly and consistently in consecutive frames. We also tried some other values in Table 7." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.833, + 0.766, + 0.849 + ], + "angle": 0, + "content": "3.4. Temporal Interaction Module" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.893, + 0.902 + ], + "angle": 0, + "content": "Adaptive Aggregation for Temporal Enhancement. Issues such as blurring or occlusion are often seen in a video stream. An intuitive idea to solve this problem is using" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "9903" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.142, + 0.089, + 0.408, + 0.301 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.313, + 0.47, + 0.36 + ], + "angle": 0, + "content": "Figure 2. Illustration of Temporal Interaction Module. \\(\\widetilde{E}_{tck}^{t+1}\\) and \\(\\widetilde{M}_{tck}^{t+1}\\) are the prediction of \\(E_{tck}^{t}\\) and \\(M_{tck}^{t}\\) for the next frame, respectively." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.385, + 0.468, + 0.491 + ], + "angle": 0, + "content": "multi-frame features to enhance the single-frame representation. Therefore, we fuse the outputs from two adjacent frames with an adaptive aggregation algorithm in our MeM-OTR. Due to occlusions and blurring, the output embedding \\(O_{tck}^{t}\\) of the current frame may be unreliable. Thus, as illustrated in Figure 2, we generate a channel-wise weight \\(W_{tck}^{t}\\) for each tracked instance to alleviate this problem:" + }, + { + "type": "equation", + "bbox": [ + 0.166, + 0.506, + 0.469, + 0.524 + ], + "angle": 0, + "content": "\\[\nW _ {t c k} ^ {t} = \\operatorname {S i g m o i d} \\left(\\operatorname {M L P} \\left(O _ {t c k} ^ {t}\\right)\\right). \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.53, + 0.469, + 0.621 + ], + "angle": 0, + "content": "We multiply this weight \\( W_{tck}^{t} \\) with the current output \\( O_{tck}^{t} \\) and then concatenate the result with \\( O_{tck}^{t-1} \\) from the previous frame. Furthermore, we apply a two-layer MLP to produce the fusion outcome \\( \\widetilde{O}_{tck}^{t} \\). This adaptive aggregation enhances the target representation with short-term temporal modeling." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.621, + 0.469, + 0.713 + ], + "angle": 0, + "content": "However, we do not use the above channel-wise weight for previous output \\( O_{tck}^{t-1} \\). As we will discuss in Section 3.5, there is a difference between \\( O_{tck}^{t} \\) and \\( O_{tck}^{t-1} \\). During inference, we employ a score threshold \\( \\tau_{tck} \\) to guarantee that \\( O_{tck}^{t-1} \\) is relatively reliable. Therefore, we input it entirely into the subsequent fusion step without the adaptive weight." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.469, + 0.809 + ], + "angle": 0, + "content": "Generate Track Embedding. As discussed in Section 3.1, we exploit the track embedding \\( E_{tck}^{t} \\) to produce the location and category of each tracked target. Therefore, generating more reliable and distinguishable track embedding is the key to improving tracking performance. Our processing is illustrated in Figure 2." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.469, + 0.902 + ], + "angle": 0, + "content": "Since there are multiple similar objects in the same frame, we believe that learning more discriminative representations is also crucial to the tracker. Thus we employ a Multi-Head Attention [31] structure called memory-attention layer to achieve this interaction between different trajectories. Due to the reliability of long-term memory" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.09, + 0.891, + 0.122 + ], + "angle": 0, + "content": "\\(M_{tck}^{t}\\), we use it as \\(K\\), and the aggregation \\(\\hat{O}_{tck}^{t}\\) and the output embedding \\(O_{tck}^{t}\\) as \\(Q\\) and \\(V\\), respectively." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.123, + 0.892, + 0.273 + ], + "angle": 0, + "content": "After that, we combine long-term memory \\( M_{tck}^{t} \\) and the result of memory-attention layer using addition, then input into an FFN network to predict the subsequent track embedding \\( \\widetilde{E}_{tck}^{t+1} \\). As shown in Equation (1), long-term memory is gradually changing over time. Therefore, by incorporating information from long-term memory, the track embedding \\( \\widetilde{E}_{tck}^{t+1} \\) avoids abrupt changes that may cause association mistakes in consecutive frames. This design significantly improves the performance of object association, corroborated by ablation experiments shown in Table 6." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.283, + 0.667, + 0.297 + ], + "angle": 0, + "content": "3.5. Inference Details" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.307, + 0.892, + 0.382 + ], + "angle": 0, + "content": "At time step \\(t\\), we jointly input the learnable detect query \\(Q_{det}\\) and track embedding \\(E_{tck}^{t}\\) (\\(E_{tck}^{0} = \\emptyset\\)) into our model to produce detection and tracking results, respectively. The detection result with a confidence score of more than \\(\\tau_{det}\\) will transform into a newborn object." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.382, + 0.892, + 0.457 + ], + "angle": 0, + "content": "Target occlusion is a common issue in multi-object tracking task. If a tracked object is lost (confidence \\(\\leq \\tau_{tck}\\)) in the current frame, we do not directly remove its track embedding but mark it as inactive trajectory. Afterward, the inactive target will be removed entirely after \\(\\mathcal{T}_{miss}\\) frames." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.459, + 0.892, + 0.534 + ], + "angle": 0, + "content": "It is worth noting that we do not update the track embedding and long-term memory at every time step for each object. Instead, we choose to update those track embedding with high confidence. The choice of update threshold \\(\\tau_{next}\\) yields the following formulation for updating:" + }, + { + "type": "equation", + "bbox": [ + 0.525, + 0.557, + 0.891, + 0.598 + ], + "angle": 0, + "content": "\\[\n\\left[ E _ {i} ^ {t + 1}, M _ {i} ^ {t + 1} \\right] = \\left\\{ \\begin{array}{l l} \\left[ \\widetilde {E} _ {i} ^ {t + 1}, \\widetilde {M} _ {i} ^ {t + 1} \\right], & c _ {i} ^ {t} > \\tau_ {\\text {n e x t}} \\\\ \\left[ E _ {i} ^ {t}, M _ {i} ^ {t} \\right], & c _ {i} ^ {t} \\leq \\tau_ {\\text {n e x t}} \\end{array} , \\right. \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.61, + 0.892, + 0.733 + ], + "angle": 0, + "content": "where \\(i\\) is the target index, \\(t\\) is the frame index, and \\(c_i^t\\) is the predicted classification confidence of the \\(i^{th}\\) object at time step \\(t\\). \\(\\widetilde{E}_i^{t + 1}\\) and \\(\\widetilde{M}_i^{t + 1}\\) are the predictions of track embedding and long-term memory, generated by Temporal Interaction Module shown in Figure 2. For simplicity, we set \\(\\tau_{det} = \\tau_{tck} = \\tau_{next} = 0.5\\) in our experiments. \\(\\mathcal{T}_{miss}\\) is set to 30, 15 and 10 on DanceTrack, MOT17 and BDD100K, respectively." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.747, + 0.633, + 0.763 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.772, + 0.698, + 0.786 + ], + "angle": 0, + "content": "4.1. Datasets and Metrics" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.795, + 0.892, + 0.87 + ], + "angle": 0, + "content": "Datasets. We mainly evaluate MeMOTR on the DanceTrack [29] dataset since they have more severe association challenges than traditional pedestrian tracking datasets. For a comprehensive evaluation, we also conduct experiments on MOT17 [23] and BDD100K [41]." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Metrics. Because of providing a balanced way to measure both detection and association performance explicitly," + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "9904" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.091, + 0.471, + 0.168 + ], + "angle": 0, + "content": "we use Higher Order Metric for Evaluating Multi-Object Tracking (HOTA) [21] to evaluate our method, especially analyzing our memory mechanism using Association Accuracy (AssA). We also list the MOTA [2] and IDF1 [25] metrics in our experimental results." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.178, + 0.295, + 0.194 + ], + "angle": 0, + "content": "4.2. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.201, + 0.468, + 0.261 + ], + "angle": 0, + "content": "Following the settings in MOTR [42], we use several data augmentation methods, such as random resize and random crop. The shorter side of the input image is resized to 800, and the maximum size is restricted to 1536." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.262, + 0.47, + 0.564 + ], + "angle": 0, + "content": "We built MeMOTR upon DAB-Deformable-DETR [20] with a ResNet50 [15] backbone and initialize our model with the official DAB-Deformable-DETR [20] weights pretrained on the COCO [19] dataset. We suggest that the anchor-based position-prior from DAB-Deformable-DETR is quite effective due to the tracked box's smoothness in time and can be further exploited in future works. We also provide the results of our model based on Deformable-DETR [48] for fair comparison in Table 1. Our models are conducted on PyTorch with 8 NVIDIA Tesla V100 GPUs. By using PyTorch gradient checkpoint technology, we implement a memory-optimized version that can also be trained on NVIDIA GPUs with less than 10GB GPU memory. The batch size is set to 1 per GPU, and each batch contains a video clip with multiple frames. Within each clip, video frames are sampled with random intervals from 1 to 10. We use the AdamW optimizer with the initial learning rate of \\(2.0 \\times 10^{-4}\\). During training, we filter out the tracked target lower than the score threshold \\(\\tau_{update} = 0.5\\) and IoU threshold \\(\\tau_{IoU} = 0.5\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.565, + 0.47, + 0.837 + ], + "angle": 0, + "content": "On DanceTrack [29], we train MeMOTR for 18 epochs on the train set and drop the learning rate by a factor of 10 at the \\(12^{th}\\) epoch. Firstly, we use two frames within a clip for training. And then increase the clip frames to 3, 4, and 5 at the \\(6^{th}\\), \\(10^{th}\\), and \\(14^{th}\\) epochs, respectively. On MOT17 [23], due to the small train set (about 5K frames), it is easy to cause overfitting problems. Therefore, we add CrowdHuman [27] validation set to build a joint train set with MOT17 training data. CrowdHuman val set provides about 4K static images. Therefore, we apply random shifts from CenterTrack [46] to generate pseudo trajectories. Finally, we train MeMOTR for 130 epochs, and the learning rate decays by a factor of 10 at the \\(120^{th}\\) epoch. The initial length of the training video clip is 2 and gradually increases to 3 and 4 at the \\(60^{th}\\) and \\(100^{th}\\) epochs, respectively. On BDD100K [41], we modify the sampling length at the \\(6^{th}\\) and \\(10^{th}\\) epochs and totally train 14 epochs while reducing the learning rate at the \\(12^{th}\\) epoch." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.847, + 0.421, + 0.863 + ], + "angle": 0, + "content": "4.3. Comparison on the DanceTrack Dataset" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.468, + 0.9 + ], + "angle": 0, + "content": "Since DanceTrack [29] is a dataset with various motions that cannot be modeled by classic linear motion estima" + }, + { + "type": "table", + "bbox": [ + 0.521, + 0.09, + 0.875, + 0.351 + ], + "angle": 0, + "content": "
MethodsHOTADetAAssAMOTAIDF1
w/o extra data:
FairMOT [44]39.766.723.882.240.8
CenterTrack [46]41.878.122.686.835.7
TraDeS [36]43.374.525.486.241.2
TransTrack [30]45.575.927.588.445.2
ByteTrack [43]47.771.032.189.653.9
GTR [47]48.072.531.984.750.3
QDTrack [24]54.280.136.887.750.4
MOTR [42]54.273.540.279.751.5
OC-SORT [5]55.180.338.392.054.6
C-BIoU [40]60.681.345.491.661.6
MeMOTR* (ours)63.477.052.385.465.5
MeMOTR (ours)68.580.558.489.971.2
with extra data:
MT_IoT [39]66.784.153.094.070.6
MOTRv2 [45]69.983.059.091.971.7
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.362, + 0.892, + 0.416 + ], + "angle": 0, + "content": "Table 1. Performance comparison with state-of-the-art methods on the DanceTrack [29] test set. Results for existing methods are from DanceTrack [29]. MeMOTR* means the result based on standard Deformable-DETR." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.441, + 0.891, + 0.471 + ], + "angle": 0, + "content": "tion [3, 5], it provides a better choice to verify our tracking performance, especially the association performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.472, + 0.892, + 0.638 + ], + "angle": 0, + "content": "We compare MeMOTR with the state-of-the-art methods on the DanceTrack [29] test set in Table 1. Our method achieves 68.5 HOTA and gains a vast lead on the AssA metric (58.4 AssA), even surpassing some methods [39] that use additional datasets for training. Due to the limitations of the linear motion estimation module, some tracking-by-detection methods, for example, ByteTrack [43], although they can achieve great detection results (71.0 DetA), still cannot handle complex object association problems (32.1 AssA). However, their MOTA metrics are still high because MOTA overemphasizes detection performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.639, + 0.892, + 0.774 + ], + "angle": 0, + "content": "Our temporal interaction module, shown in Figure 2, leverages temporal information gracefully and efficiently. Moreover, the separated detection decoder \\( \\mathcal{D}_{det} \\) discussed in Section 3.2 alleviates the conflicts between detection and tracking tasks. Therefore, we earn an impressive association performance (58.4 AssA and 71.2 IDF1) and competitive detection performance (80.5 DetA) compared with the state-of-the-art methods. We further prove our components' effectiveness in Section 4.6." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.786, + 0.809, + 0.801 + ], + "angle": 0, + "content": "4.4. Comparison on the MOT17 Dataset" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.81, + 0.891, + 0.869 + ], + "angle": 0, + "content": "In order to make a comprehensive comparison, we also evaluate our method on the classic pedestrian tracking benchmark. Table 2 compares our method with state-of-the-art methods on the MOT17 [23] test set." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Recent tracking-by-detection methods [40, 43] exploit robust detectors (like YOLOX [12]) to achieve really excel" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "9905" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.099, + 0.09, + 0.451, + 0.441 + ], + "angle": 0, + "content": "
MethodsHOTADetAAssAMOTAIDF1
CNN based:
Tracktor++ [1]44.844.945.153.552.3
CenterTrack [46]52.253.851.067.864.7
TraDeS [36]52.755.250.869.163.9
QDTrack [24]53.955.652.768.766.3
GTR [47]59.161.657.075.371.5
FairMOT [44]59.360.958.073.772.3
DeepSORT [34]61.263.159.778.074.5
SORT [3]63.064.262.280.178.2
ByteTrack [43]63.164.562.080.377.3
Quo Vadis [10]63.164.662.180.377.7
OC-SORT [5]63.263.263.478.077.5
C-BIoU [40]64.164.863.781.179.7
Transformer based:
TrackFormer [22]///74.168.0
TransTrack [30]54.161.647.974.563.9
TransCenter [37]54.560.149.773.262.2
MeMOT [4]56.9/55.272.569.0
MOTR [42]57.258.955.871.968.4
MeMOTR (ours)58.859.658.472.871.5
Hybird based:
MOTRv2 [45]62.063.860.678.675.0
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.451, + 0.47, + 0.507 + ], + "angle": 0, + "content": "Table 2. Performance comparison with state-of-the-art methods on the MOT17 [23] test set. The best performance among the Transformer-based methods is marked in **bold. MOTRv2** [45] is marked in **hybrid** since their YOLOX [12] proposals." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.536, + 0.47, + 0.793 + ], + "angle": 0, + "content": "lent detection performance (up to 64.8 DetA). Since performance on MOT17 overemphasizes detection performance, these methods perform immensely well. In this regard, there is still a massive gap in the detection performance of Transformer-based methods [4, 42] because too many dense and small object predictions are involved. In addition, the joint query in a shared Transformer decoder produces tracking and detection simultaneously, which may cause internal conflicts. The detect query is inhibited by the track query in the self-attention [31] structure, limiting the ability to detect newborn objects, especially those close to tracked targets, and vice versa. Because of this, TransTrack [30] achieves significantly better detection performance (61.6 DetA) due to its siamese network structure. This architecture decouples tracking and detection to resolve the above conflict, but its simple post-processing matching algorithm decreases its association performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.471, + 0.901 + ], + "angle": 0, + "content": "On the other hand, we found that Transformer-based methods [42] suffer from serious overfitting problems in MOT17 [23] because of the tiny train set, which only contains about 5K frames. Although we use an additional CrowdHuman validation set for training mentioned in Section 4.2, severe overfitting still happens. Thus, we get \\(\\sim 90.0\\) HOTA and \\(\\sim 95.0\\) MOTA on the train set. However," + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.09, + 0.888, + 0.192 + ], + "angle": 0, + "content": "
MethodmTETAmHOTAmLocAmAssocAmAssA
QDTrack [24]47.8/45.948.5/
DeepSORT [34]48.0/46.446.7/
MOTR [42]50.737.035.851.047.3
TETer [18]50.8/47.252.9/
MeMOTR (ours)53.640.438.156.752.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.202, + 0.892, + 0.23 + ], + "angle": 0, + "content": "Table 3. Performance comparison on the BDD100K [41] val set. Results for existing methods are from [18]." + }, + { + "type": "image", + "bbox": [ + 0.53, + 0.245, + 0.695, + 0.33 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.7, + 0.245, + 0.862, + 0.33 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.53, + 0.336, + 0.693, + 0.42 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.539, + 0.422, + 0.683, + 0.432 + ], + "angle": 0, + "content": "Before Detection Decoder" + }, + { + "type": "image", + "bbox": [ + 0.7, + 0.336, + 0.862, + 0.42 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.713, + 0.422, + 0.848, + 0.432 + ], + "angle": 0, + "content": "After Detection Decoder" + }, + { + "type": "image", + "bbox": [ + 0.536, + 0.438, + 0.858, + 0.458 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.476, + 0.892, + 0.504 + ], + "angle": 0, + "content": "Figure 3. Visualize the anchors of tracked and newborn targets before (left) and after (right) the separated detection decoder \\( \\mathcal{D}_{\\text{det}} \\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.531, + 0.892, + 0.576 + ], + "angle": 0, + "content": "too much additional training data can lead to inductive bias toward static people. Therefore, we argue that the train set of MOT17 is too small to train our model completely." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.577, + 0.892, + 0.727 + ], + "angle": 0, + "content": "Eventually, our method slightly improves the performance on the MOT17 test set to 58.8 HOTA. We gain competitive detection accuracy (DetA) compared with other Transformer-based methods. In particular, we improved the performance of object association, which AssA and IDF1 metrics can reflect. As a method that also uses the memory mechanism, our MeMOTR achieves higher AssA and IDF1, surpassing MeMOT [4] by \\(3.2\\%\\) and \\(2.5\\%\\), respectively. These experimental results further validate the effectiveness of our method." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.74, + 0.829, + 0.756 + ], + "angle": 0, + "content": "4.5. Comparison on the BDD100K Dataset" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.764, + 0.892, + 0.87 + ], + "angle": 0, + "content": "In order to evaluate our method in multi-category scenarios, we also evaluate our method on the BDD100K [41] val set in Table 3. To better assess multi-class tracking performance, we leverage Tracking-Every-Thing Accuracy (TETA) metric for ranking as they did in BDD100K MOT Challenge 2023. We re-evaluate MOTR [42] on the new metrics using the official model for comparison." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "The results show that our method can generalize well to multi-class scenarios and achieve impressive performance" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "9906" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.107, + 0.089, + 0.444, + 0.164 + ], + "angle": 0, + "content": "
LDetHOTADetAAssAMOTAIDF1
062.174.352.283.165.6
163.974.655.083.467.1
263.273.854.381.965.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.174, + 0.47, + 0.204 + ], + "angle": 0, + "content": "Table 4. Ablation experiments on the layers of the separate Detection Decoder, which is denoted as \\( \\mathcal{L}_{\\mathcal{D}_{det}} \\)." + }, + { + "type": "table", + "bbox": [ + 0.113, + 0.215, + 0.436, + 0.318 + ], + "angle": 0, + "content": "
\\(O_{t-1}\\)\\(W_{tck}^{t}\\)HOTADetAAssAIDF1
62.373.952.764.6
✓62.474.552.564.6
✓62.774.453.165.3
✓✓63.974.655.067.1
" + }, + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.328, + 0.462, + 0.342 + ], + "angle": 0, + "content": "Table 5. Ablations on different designs of Adaptive Aggregation." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.367, + 0.47, + 0.414 + ], + "angle": 0, + "content": "(53.6 TETA), especially in association (56.7 mAssocA), further demonstrating the effectiveness of our proposed method for associating targets." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.423, + 0.231, + 0.439 + ], + "angle": 0, + "content": "4.6. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.447, + 0.47, + 0.765 + ], + "angle": 0, + "content": "In this section, we study several components of our model, such as the long-term memory, adaptive aggregation, memory-attention layer, and separated detection decoder. Since our main contribution is a better utilization of temporal information, we choose to conduct ablation experiments on DanceTrack [29] due to its more severe object association challenges. On the other hand, DanceTrack [29] has more extensive training data to avoid severe overfitting (about \\(10 \\times\\) compared with MOT17 [23]). We train our model on the train set and evaluate it on the official val set. Detection Decoder. For joint tracking and detection, the tracking-by-query paradigm processes detect and track queries in a shared Transformer decoder from scratch. However, the track query has rich semantic content from the previous tracked targets, in contrast to the object query for detection. On the other hand, learnable detect anchors often cover a larger range to find potential targets. In contrast, the anchor of tracked object pays more attention to a small area where the target appeared in the previous frame. This may cause a large gap between the anchors of tracked and newborn objects, as we visualized in Figure 3 (left)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.902 + ], + "angle": 0, + "content": "In this paper, we apply a separated Transformer decoder layer to perform preliminary target detection. The output \\( E_{det}^{t} \\) of this Detection Decoder \\( \\mathcal{D}_{det} \\) will be better aligned with the track embedding \\( E_{tck}^{t} \\) generated by the previous frame to improve the tracking performance. We experimentally confirmed the effectiveness of this design, as shown in Table 4. Using only one separate Detection Decoder layer dramatically improves HOTA and AssA metrics by \\( 1.8\\% \\) and \\( 2.8\\% \\), respectively. However, continuing to increase" + }, + { + "type": "table", + "bbox": [ + 0.54, + 0.089, + 0.858, + 0.212 + ], + "angle": 0, + "content": "
MtckattnHOTADetAAssAIDF1
naïve61.174.250.663.7
61.973.852.164.1
✓62.574.252.964.7
✓61.174.050.762.4
✓✓63.974.655.067.1
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.223, + 0.894, + 0.266 + ], + "angle": 0, + "content": "Table 6. Ablation study of long-term memory \\( M_{tck}^{t} \\) and memory-attention layer \\( attn \\). naive means a naive baseline with a single FFN for \\( O_{tck}^{t} \\) to generate the track embedding \\( \\tilde{E}_{tck}^{t+1} \\)." + }, + { + "type": "table", + "bbox": [ + 0.541, + 0.28, + 0.855, + 0.37 + ], + "angle": 0, + "content": "
λHOTA↑DetA↑AssA↑IDF1↑IDsw ↓
0.00562.674.253.165.11383
0.0163.974.655.067.11237
0.0263.275.053.566.01213
0.0463.575.154.066.31295
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.38, + 0.885, + 0.394 + ], + "angle": 0, + "content": "Table 7. Ablation study on the long-term memory update ratio \\( \\lambda \\) ." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.422, + 0.892, + 0.498 + ], + "angle": 0, + "content": "the layers of the Detection Decoder will reduce the refinement steps of track embeddings, thus slightly weakening the association performance. Furthermore, we visualize the bounding boxes after Detection Decoder in Figure 3 (right). This indicates that \\( \\mathcal{D}_{det} \\) is able to locate objects roughly." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.5, + 0.892, + 0.544 + ], + "angle": 0, + "content": "Adaptive Aggregation. In Section 3.4, we design an adaptive aggregation, which dynamically fuses object features from adjacent frames. We ablate this structure in Table 5." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.546, + 0.892, + 0.655 + ], + "angle": 0, + "content": "The first two results only use the current output \\(O_{tck}^{t}\\) to generate the temporal aggregation \\(\\hat{O}_{tck}^{t}\\). In contrast, the next two lines fuse the previous output \\(\\hat{O}_{tck}^{t-1}\\) into \\(\\hat{O}_{tck}^{t}\\). Introducing \\(O_{tck}^{t-1}\\) provides additional object features from neighboring frames, thus improving tracking performance. We suppose this offers a complementary feature augmentation that can combat video ambiguity and uncertainty." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.656, + 0.892, + 0.777 + ], + "angle": 0, + "content": "Furthermore, we explore the impact of the dynamic weight \\( W_{tck}^{t} \\). As shown in Table 5, it only provides a little boost without \\( O_{tck}^{t-1} \\) from the previous. We explain that dynamic \\( W_{tck}^{t} \\) leads to missing information without complementary features from previous \\( O_{tck}^{t-1} \\). The result of the last row shows that utilizing both dynamic weight \\( W_{tck}^{t} \\) and previous output \\( O_{tck}^{t-1} \\) produces significantly better performance, with +2.6% HOTA and +2.3% AssA." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.779, + 0.892, + 0.839 + ], + "angle": 0, + "content": "Long-Term Memory. We propose a long-term memory in Section 3.3 to utilize longer temporal information and further inject it into subsequent track embedding to augment the object feature." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.901 + ], + "angle": 0, + "content": "We explore the impact of long-term memory \\( M_{tck}^{t} \\) and show the experimental results in Table 6. For a more comprehensive comparison, we also experiment with another track embedding generation structure that removes the" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "9907" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.088, + 0.099, + 0.273, + 0.243 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.091, + 0.252, + 0.273, + 0.264 + ], + "angle": 0, + "content": "(a) w/o memory and w/o attention" + }, + { + "type": "image", + "bbox": [ + 0.289, + 0.099, + 0.477, + 0.243 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.297, + 0.252, + 0.472, + 0.264 + ], + "angle": 0, + "content": "(b) \\( w / o \\) memory and \\( w/ \\) attention" + }, + { + "type": "image", + "bbox": [ + 0.491, + 0.099, + 0.679, + 0.243 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.252, + 0.674, + 0.264 + ], + "angle": 0, + "content": "(c) \\( w/ \\) memory and \\( w/o \\) attention" + }, + { + "type": "image", + "bbox": [ + 0.693, + 0.099, + 0.882, + 0.243 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.688, + 0.252, + 0.89, + 0.264 + ], + "angle": 0, + "content": "(d) \\( w/ \\) memory and \\( w/ \\) attention (ours)" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.269, + 0.893, + 0.325 + ], + "angle": 0, + "content": "Figure 4. Visualization of Track Embedding \\( E_{tck}^{t} \\) (the first 50 frames in sequence dancetrack0063) from different structure designs by using t-Distributed Stochastic Neighbor Embedding (t-SNE). Track embeddings for different tracked targets (IDs) are marked in different colors and shapes. Our design 4(d) helps the model learn a more stable and distinguishable representation for the track embedding. Corresponding tracking performance is shown in Table 6." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.351, + 0.468, + 0.381 + ], + "angle": 0, + "content": "memory-attention layer by passing the temporal aggregation \\(\\hat{O}_{tck}^{t}\\) directly to an FFN network." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.381, + 0.469, + 0.471 + ], + "angle": 0, + "content": "Our experimental results show that utilizing long-term memory produces a better association performance, with \\(+0.8\\%\\) and \\(+4.3\\%\\) AssA for w/o and w/ memory-attention layer. The injection of long-term memory significantly stabilizes and augments the identity information of each track embedding, as visualized in Figure 4(c) and 4(d)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.473, + 0.469, + 0.653 + ], + "angle": 0, + "content": "Memory Attention. In Table 6, we also ablate memory-attention layer. It shows that by using memory-attention layer, our MeMOTR achieves much better performance (63.9 vs. 62.5 HOTA), especially improving AssA by \\(2.1\\%\\). This attention layer establishes interactions between different trajectories that help the track embedding learns discriminative features. However, without long-term memory \\(M_{tck}^{t}\\), memory-attention layer produces worse performance \\((-1.4\\%)\\) AssA and \\(-1.7\\%\\) IDF1. We explain that the track embedding without memory augmentation is unstable. Therefore, interacting with such unreliable information can be counterproductive, as visualized in Figure 4(b)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.654, + 0.469, + 0.805 + ], + "angle": 0, + "content": "Memory Update Rate. Here, we explored the impact of long-term memory update rate \\(\\lambda\\) on the tracking performance in Equation 1. As shown in Table 7, when progressively increasing the \\(\\lambda_{L}\\) from 0.005 to 0.04, our model achieves the highest HOTA score at \\(\\lambda = 0.01\\) while DetA score is decreasing slightly. We suggest the update rate \\(\\lambda\\) may be a hyperparameter that needs to be chosen according to different datasets. For example, scenarios with plenty of target non-rigid deformation may need a higher memory update rate to adapt to the rapidly changing features." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.817, + 0.203, + 0.831 + ], + "angle": 0, + "content": "4.7. Limitations" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.469, + 0.901 + ], + "angle": 0, + "content": "Although our MeMOTR brings a significant improvement in association performance, detection performance is still a drawback, especially in crowded scenarios (like MOT17 [23]). During experiments, we observed that some" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.351, + 0.892, + 0.516 + ], + "angle": 0, + "content": "times newborn objects are suppressed by tracked targets in the self-attention structure, which leads to reduced detection performance. Therefore, resolving this conflict is a crucial challenge for the joint tracking paradigm. This may help improve the detection capabilities, which can boost the overall tracking performance of the model, as studied in [45]. In addition, in pedestrian tracking, existing datasets are still limited in size and diversity. We suggest that training with other simulation datasets (like MOTSynth [11]) may alleviate the overfitting problem of our model and achieve better tracking performance." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.538, + 0.618, + 0.553 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.567, + 0.892, + 0.777 + ], + "angle": 0, + "content": "We have proposed MeMOTR, an end-to-end long-term memory-augmented Transformer for multi-object tracking. Our method builds a stable long-term memory for each tracked object and exploits this memory to augment the representation of track embedding, thus improving its association performance. Furthermore, by leveraging a memory-attention layer, our model makes different targets more distinguishable. As a result, our approach achieves the state-of-the-art performance on MOT benchmarks, especially in scenes with irregular motion patterns. Extensive ablation experiments and visualizations demonstrate the effectiveness of our components. We hope that future work will pay more attention to the use of long-term temporal information for object tracking." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Acknowledgements. This work is supported by National Key R&D Program of China (No. 2022ZD0160900), National Natural Science Foundation of China (No. 62076119, No. 61921006), Fundamental Research Funds for the Central Universities (No. 020214380091, No. 020214380099), and Collaborative Innovation Center of Novel Software Technology and Industrialization. Besides, Ruopeng Gao would like to thank Muyan Yang for her social support." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "9908" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.47, + 0.157 + ], + "angle": 0, + "content": "[1] Philipp Bergmann, Tim Meinhardt, and Laura Leal-Taixe. Tracking without bells and whistles. In ICCV, pages 941-951. IEEE, 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.16, + 0.47, + 0.2 + ], + "angle": 0, + "content": "[2] Keni Bernstein and Rainer Stiefelhagen. Evaluating multiple object tracking performance: The CLEAR MOT metrics. EURASIP J. Image Video Process., 2008, 2008. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.203, + 0.469, + 0.243 + ], + "angle": 0, + "content": "[3] Alex Bewley, ZongYuan Ge, Lionel Ott, Fabio Tozeto Ramos, and Ben Upcroft. Simple online and realtime tracking. In ICIP, pages 3464-3468. IEEE, 2016. 1, 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.246, + 0.469, + 0.3 + ], + "angle": 0, + "content": "[4] Jiarui Cai, Mingze Xu, Wei Li, Yuanjun Xiong, Wei Xia, Zhuowen Tu, and Stefano Soatto. Memot: Multi-object tracking with memory. In CVPR, pages 8080-8090. IEEE, 2022. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.304, + 0.469, + 0.358 + ], + "angle": 0, + "content": "[5] Jinkun Cao, Xinshuo Weng, Rawal Khirodkar, Jiangmiao Pang, and Kris Kitani. Observation-centric SORT: rethinking SORT for robust multi-object tracking. CoRR, abs/2203.14360, 2022. 1, 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.361, + 0.469, + 0.429 + ], + "angle": 0, + "content": "[6] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In ECCV(1), volume 12346 of Lecture Notes in Computer Science, pages 213-229. Springer, 2020. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.432, + 0.469, + 0.487 + ], + "angle": 0, + "content": "[7] Wongun Choi and Silvio Savarese. A unified framework for multi-target tracking and collective activity recognition. In ECCV (4), volume 7575 of Lecture Notes in Computer Science, pages 215-230. Springer, 2012. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.489, + 0.469, + 0.543 + ], + "angle": 0, + "content": "[8] Yutao Cui, Chenkai Zeng, Xiaoyu Zhao, Yichun Yang, Gangshan Wu, and Limin Wang. SportsMOT: A large multi-object tracking dataset in multiple sports scenes. In ICCV, 2023. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.546, + 0.469, + 0.613 + ], + "angle": 0, + "content": "[9] Patrick Dendorfer, Hamid Rezatofighi, Anton Milan, Javen Shi, Daniel Cremers, Ian D. Reid, Stefan Roth, Konrad Schindler, and Laura Leal-Taixe. MOT20: A benchmark for multi object tracking in crowded scenes. CoRR, abs/2003.09003, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.617, + 0.469, + 0.671 + ], + "angle": 0, + "content": "[10] Patrick Dendorfer, Vladimir Yugay, Aljosa Osep, and Laura Leal-Taixe. Quo vadis: Is trajectory forecasting the key towards long-term multi-object tracking? In NeurIPS, 2022. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.674, + 0.469, + 0.743 + ], + "angle": 0, + "content": "[11] Matteo Fabbri, Guillem Brasó, Gianluca Maugeri, Orcun Cetintas, Riccardo Gasparini, Aljosa Osep, Simone Calderara, Laura Leal-Taixe, and Rita Cucchiara. Motsynth: How can synthetic data help pedestrian detection and tracking? In ICCV, pages 10829-10839. IEEE, 2021. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.746, + 0.469, + 0.786 + ], + "angle": 0, + "content": "[12] Zheng Ge, Songtao Liu, Feng Wang, Zeming Li, and Jian Sun. YOLOX: exceeding YOLO series in 2021. CoRR, abs/2107.08430, 2021. 1, 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.789, + 0.469, + 0.857 + ], + "angle": 0, + "content": "[13] Silvio Giancola, Mohieddine Amine, Tarek Dghaily, and Bernard Ghanem. Socernet: A scalable dataset for action spotting in soccer videos. In CVPR Workshops, pages 1711-1721. Computer Vision Foundation / IEEE Computer Society, 2018. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.86, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[14] Agrim Gupta, Justin Johnson, Li Fei-Fei, Silvio Savarese, and Alexandre Alahi. Social GAN: socially acceptable trajectories with generative adversarial networks. In CVPR," + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "pages 2255-2264. Computer Vision Foundation / IEEE Computer Society, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.122, + 0.892, + 0.162 + ], + "angle": 0, + "content": "[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778. IEEE Computer Society, 2016. 2, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.164, + 0.892, + 0.217 + ], + "angle": 0, + "content": "[16] Weiming Hu, Tieniu Tan, Liang Wang, and Stephen J. Maybank. A survey on visual surveillance of object motion and behaviors. IEEE Trans. Syst. Man Cybern. Part C, 34(3):334-352, 2004. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.219, + 0.892, + 0.258 + ], + "angle": 0, + "content": "[17] Bruno Korbar and Andrew Zisserman. End-to-end tracking with a multi-query transformer. CoRR, abs/2210.14601, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.261, + 0.892, + 0.315 + ], + "angle": 0, + "content": "[18] Siyuan Li, Martin Danelljan, Henghui Ding, Thomas E. Huang, and Fisher Yu. Tracking every thing in the wild. In ECCV (22), volume 13682 of Lecture Notes in Computer Science, pages 498-515. Springer, 2022. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.317, + 0.892, + 0.385 + ], + "angle": 0, + "content": "[19] Tsung-Yi Lin, Michael Maire, Serge J. Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C. Lawrence Zitnick. Microsoft COCO: common objects in context. In ECCV (5), volume 8693 of Lecture Notes in Computer Science, pages 740-755. Springer, 2014. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.387, + 0.892, + 0.439 + ], + "angle": 0, + "content": "[20] Shilong Liu, Feng Li, Hao Zhang, Xiao Yang, Xianbiao Qi, Hang Su, Jun Zhu, and Lei Zhang. DAB-DETR: dynamic anchor boxes are better queries for DETR. In ICLR. OpenReview.net, 2022. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.442, + 0.892, + 0.508 + ], + "angle": 0, + "content": "[21] Jonathon Luiten, Aljosa Osep, Patrick Dendorfer, Philip H. S. Torr, Andreas Geiger, Laura Leal-Taixe, and Bastian Leibe. HOTA: A higher order metric for evaluating multi-object tracking. Int. J. Comput. Vis., 129(2):548-578, 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.512, + 0.892, + 0.565 + ], + "angle": 0, + "content": "[22] Tim Meinhardt, Alexander Kirillov, Laura Leal-Taixe, and Christoph Feichtenhofer. Trackformer: Multi-object tracking with transformers. In CVPR, pages 8834-8844. IEEE, 2022. 1, 2, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.568, + 0.892, + 0.621 + ], + "angle": 0, + "content": "[23] Anton Milan, Laura Leal-Taixe, Ian D. Reid, Stefan Roth, and Konrad Schindler. MOT16: A benchmark for multi-object tracking. CoRR, abs/1603.00831, 2016. 1, 2, 4, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.624, + 0.892, + 0.677 + ], + "angle": 0, + "content": "[24] Jiangmiao Pang, Linlu Qiu, Xia Li, Haofeng Chen, Qi Li, Trevor Darrell, and Fisher Yu. Quasi-dense similarity learning for multiple object tracking. In CVPR, pages 164-173. Computer Vision Foundation / IEEE, 2021. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.679, + 0.892, + 0.748 + ], + "angle": 0, + "content": "[25] Ergys Ristani, Francesco Solera, Roger S. Zou, Rita Cucchiara, and Carlo Tomasi. Performance measures and a data set for multi-target, multi-camera tracking. In ECCV Workshops (2), volume 9914 of Lecture Notes in Computer Science, pages 17-35, 2016. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.749, + 0.892, + 0.802 + ], + "angle": 0, + "content": "[26] Ergys Ristani and Carlo Tomasi. Features for multi-target multi-camera tracking and re-identification. In CVPR, pages 6036–6046. Computer Vision Foundation / IEEE Computer Society, 2018. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.804, + 0.892, + 0.857 + ], + "angle": 0, + "content": "[27] Shuai Shao, Zijian Zhao, Boxun Li, Tete Xiao, Gang Yu, Xiangyu Zhang, and Jian Sun. Crowdhuman: A benchmark for detecting human in a crowd. CoRR, abs/1805.00123, 2018. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.86, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[28] Chris Stauffer and W. Eric L. Grimson. Adaptive background mixture models for real-time tracking. In CVPR, pages 2246-2252. IEEE Computer Society, 1999. 1, 3" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.956 + ], + "angle": 0, + "content": "9909" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.148 + ], + "angle": 0, + "content": "[29] Peize Sun, Jinkun Cao, Yi Jiang, Zehuan Yuan, Song Bai, Kris Kitani, and Ping Luo. Dancetrack: Multi-object tracking in uniform appearance and diverse motion. In CVPR, pages 20961-20970. IEEE, 2022. 1, 2, 4, 5, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.149, + 0.47, + 0.205 + ], + "angle": 0, + "content": "[30] Peize Sun, Yi Jiang, Rufeng Zhang, Enze Xie, Jinkun Cao, Xinting Hu, Tao Kong, Zehuan Yuan, Changhu Wang, and Ping Luo. Transtrack: Multiple-object tracking with transformer. CoRR, abs/2012.15460, 2020. 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.206, + 0.471, + 0.261 + ], + "angle": 0, + "content": "[31] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In NIPS, pages 5998-6008, 2017. 3, 4, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.263, + 0.471, + 0.319 + ], + "angle": 0, + "content": "[32] Zhongdao Wang, Liang Zheng, Yixuan Liu, Yali Li, and Shengjin Wang. Towards real-time multi-object tracking. In ECCV (11), volume 12356 of Lecture Notes in Computer Science, pages 107-122. Springer, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.32, + 0.471, + 0.347 + ], + "angle": 0, + "content": "[33] Greg Welch, Gary Bishop, et al. An introduction to the kalman filter. 1995. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.349, + 0.471, + 0.39 + ], + "angle": 0, + "content": "[34] Nicolai Wojke, Alex Bewley, and Dietrich Paulus. Simple online and realtime tracking with a deep association metric. In ICIP, pages 3645-3649. IEEE, 2017. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.392, + 0.471, + 0.447 + ], + "angle": 0, + "content": "[35] Sanghyun Woo, Kwanyong Park, Seoul Wug Oh, In So Kweon, and Joon-Young Lee. Tracking by associating clips. In ECCV (25), volume 13685 of Lecture Notes in Computer Science, pages 129–145. Springer, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.449, + 0.47, + 0.504 + ], + "angle": 0, + "content": "[36] Jialian Wu, Jiale Cao, Liangchen Song, Yu Wang, Ming Yang, and Junsong Yuan. Track to detect and segment: An online multi-object tracker. In CVPR, pages 12352-12361. Computer Vision Foundation / IEEE, 2021. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.505, + 0.471, + 0.56 + ], + "angle": 0, + "content": "[37] Yihong Xu, Yutong Ban, Guillaume Delorme, Chuang Gan, Daniela Rus, and Xavier Alameda-Pineda. Transcenter: Transformers with dense queries for multiple-object tracking. CoRR, abs/2103.15145, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.562, + 0.471, + 0.629 + ], + "angle": 0, + "content": "[38] Bin Yan, Yi Jiang, Peize Sun, Dong Wang, Zehuan Yuan, Ping Luo, and Huchuan Lu. Towards grand unification of object tracking. In ECCV (21), volume 13681 of Lecture Notes in Computer Science, pages 733-751. Springer, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.632, + 0.471, + 0.674 + ], + "angle": 0, + "content": "[39] Feng Yan, Zhiheng Li, Weixin Luo, Zequn jie, Fan Liang, Xiaolin Wei, and Lin Ma. Multiple object tracking challenge technical report for team mt_iot, 2022. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.676, + 0.471, + 0.731 + ], + "angle": 0, + "content": "[40] Fan Yang, Shigeyuki Odashima, Shoichi Masui, and Shan Jiang. Hard to track objects with irregular motions and similar appearances? make it easier by buffering the matching space. In WACV, pages 4788-4797. IEEE, 2023. 1, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.732, + 0.471, + 0.801 + ], + "angle": 0, + "content": "[41] Fisher Yu, Haofeng Chen, Xin Wang, Wenqi Xian, Yingying Chen, Fangchen Liu, Vashisht Madhavan, and Trevor Darrell. BDD100K: A diverse driving dataset for heterogeneous multitask learning. In CVPR, pages 2633-2642. Computer Vision Foundation / IEEE, 2020. 2, 4, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.803, + 0.471, + 0.871 + ], + "angle": 0, + "content": "[42] Fangao Zeng, Bin Dong, Yuang Zhang, Tiancai Wang, Xi-angyu Zhang, and Yichen Wei. MOTR: end-to-end multiple-object tracking with transformer. In ECCV (27), volume 13687 of Lecture Notes in Computer Science, pages 659–675. Springer, 2022. 1, 2, 3, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.471, + 0.903 + ], + "angle": 0, + "content": "[43] Yifu Zhang, Peize Sun, Yi Jiang, Dongdong Yu, Fucheng Weng, Zehuan Yuan, Ping Luo, Wenyu Liu, and Xinggang" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.903 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.135 + ], + "angle": 0, + "content": "Wang. Bytetrack: Multi-object tracking by associating every detection box. In ECCV (22), volume 13682 of Lecture Notes in Computer Science, pages 1-21. Springer, 2022. 1, 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[44] Yifu Zhang, Chunyu Wang, Xinggang Wang, Wenjun Zeng, and Wenyu Liu. Fairmot: On the fairness of detection and re-identification in multiple object tracking. Int. J. Comput. Vis., 129(11):3069-3087, 2021. 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.192, + 0.892, + 0.234 + ], + "angle": 0, + "content": "[45] Yang Zhang, Tiancai Wang, and Xiangyu Zhang. Motrv2: Bootstrapping end-to-end multi-object tracking by pretrained object detectors, 2022. 5, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.235, + 0.892, + 0.291 + ], + "angle": 0, + "content": "[46] Xingyi Zhou, Vladlen Koltun, and Philipp Krahenbuhl. Tracking objects as points. In ECCV (4), volume 12349 of Lecture Notes in Computer Science, pages 474-490. Springer, 2020. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.292, + 0.892, + 0.332 + ], + "angle": 0, + "content": "[47] Xingyi Zhou, Tianwei Yin, Vladlen Koltun, and Philipp Krahenbihl. Global tracking transformers. In CVPR, pages 8761-8770. IEEE, 2022. 2, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.334, + 0.892, + 0.388 + ], + "angle": 0, + "content": "[48] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable DETR: deformable transformers for end-to-end object detection. In ICLR. OpenReview.net, 2021. 5" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.388 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.517, + 0.957 + ], + "angle": 0, + "content": "9910" + } + ] +] \ No newline at end of file diff --git a/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/40deaafe-8b86-4716-a18c-f883acf32105_origin.pdf b/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/40deaafe-8b86-4716-a18c-f883acf32105_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..e5362d9411dd9c62708df018fe577acbb687727d --- /dev/null +++ b/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/40deaafe-8b86-4716-a18c-f883acf32105_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:61d0e84e3383395b25b05ae42802ce856a36f8f349052f2023d4e6ea8022b00c +size 3031284 diff --git a/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/full.md b/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/full.md new file mode 100644 index 0000000000000000000000000000000000000000..abf5ebe305bbe1467c915f0dc295fe7dd65538a4 --- /dev/null +++ b/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/full.md @@ -0,0 +1,313 @@ +# MeMOTR: Long-Term Memory-Augmented Transformer for Multi-Object Tracking + +Ruopeng Gao $^{1}$ Limin Wang $^{1,2,\text{四}}$ + +$^{1}$ State Key Laboratory for Novel Software Technology, Nanjing University $^{2}$ Shanghai AI Lab + +# Abstract + +As a video task, Multiple Object Tracking (MOT) is expected to capture temporal information of targets effectively. Unfortunately, most existing methods only explicitly exploit the object features between adjacent frames, while lacking the capacity to model long-term temporal information. In this paper, we propose MeMOTR, a long-term memory-augmented Transformer for multi-object tracking. Our method is able to make the same object's track embedding more stable and distinguishable by leveraging long-term memory injection with a customized memory-attention layer. This significantly improves the target association ability of our model. Experimental results on DanceTrack show that MeMOTR impressively surpasses the state-of-the-art method by $7.9\%$ and $13.0\%$ on HOTA and AssA metrics, respectively. Furthermore, our model also outperforms other Transformer-based methods on association performance on MOT17 and generalizes well on BDD100K. Code is available at https://github.com/MCG-NJU/MeMOTR. + +# 1. Introduction + +Multi-Object Tracking (MOT) [8, 23, 29] aims to detect multiple objects and maintain their identities in a video stream. MOT can be applied to numerous downstream tasks, such as action recognition [7], behavior analysis [16], and so on. It is also an important technique for real-world applications, e.g., autonomous driving and surveillance. + +According to the definition of MOT, this task can be formally divided into two parts: object detection and association. For a long time, pedestrian tracking datasets (like MOT17 [23]) have had mainstream domination in the community. However, these datasets have insufficient challenges in target association because of their almost linear motion pattern. Therefore, tracking-by-detection methods [5, 32, 43] achieve the state-of-the-art performance of MOT for several years. They first adopt a robust object de + +tector (e.g., YOLOX [12]) to independently localize the objects in each frame and associate them with IoU [3, 40] or ReID features [26]. However, associating targets becomes a critical challenge in some complex scenarios, like group dancers [29] and sports players [8, 13]. These similar appearances and erratic movements may cause existing methods to fail. Recently, Transformer-based tracking methods [22, 42] have introduced a new fully-end-to-end MOT paradigm. Through the interaction and progressive decoding of detect and track queries in Transformer, they simultaneously complete detection and tracking. This paradigm is expected to have greater potential for object association due to the flexibility of Transformer, especially in the above complex scenes. + +Although these Transformer-based methods achieve excellent performance, they still struggle with some complicated issues, such as analogous appearances, irregular motion patterns, and long-term occlusions. We hypothesize that more intelligent leverage of temporal information can provide the tracker a more effective and robust representation for each tracked target, thereby relieving the above issues and boosting the tracking performance. Unfortunately, most previous methods [22, 42] only exploit the image or object features between two adjacent frames, which lacking the utilization of long-term temporal information. + +Based on the analysis above, in this paper, we focus on leveraging temporal information by proposing a long-term Memory-augmented Multi-Object Tracking method with TRansformer, coined as MeMOTR. We exploit detect and track embeddings to localize newborn and tracked objects via a Transformer Decoder, respectively. Our model maintains a long-term memory with the exponential recursion update algorithm [28] for each tracked object. Afterward, we inject this memory into the track embedding, reducing its abrupt changes and thus improving the model association ability. As multiple tracked targets exist in a video stream, we apply a memory-attention layer to produce a more distinguishable representation. Besides, we present an adaptive aggregation to fuse the object feature from two adjacent frames to improve tracking robustness. + +In addition, we argue that the learnable detection query + +in DETR [6] has no semantic information about specific objects. However, the track query in Transformer-based MOT methods like MOTR [42] carries information about a tracked object. This difference will cause a semantic information gap and thus degrade the final tracking performance. Therefore, to overcome this issue, we use a light decoder to perform preliminary object detection, which outputs the detect embedding with specific semantics. Then we jointly input detect and track embeddings into the subsequent decoder to make MeMOTR tracking results more precise. + +We mainly evaluate our method on the DanceTrack dataset [29] because of its serious association challenge. Experimental results show that our method achieves the state-of-the-art performance on this challenging DanceTrack dataset, especially on association metrics (e.g., AssA, IDF1). We also evaluate our model on the traditional pedestrian tracking dataset of MOT17 [23] and the multicategories tracking dataset of BDD100K [41]. In addition, we perform extensive ablation studies further demonstrate the effectiveness of our designs. + +# 2. Related Work + +Tracking-by-Detection is a widely used MOT paradigm that has recently dominated the community. These methods always get trajectories by associating a given set of detections in a streaming video. + +The objects in classic pedestrian tracking scenarios [9, 23] always have different appearances and regular motion patterns. Therefore, appearance matching and linear motion estimation are widely used to match targets in consecutive frames. SORT [3] uses the Intersection-over-Union (IoU) to match predictions of the Kalman filter [33] and detected boxes. Deep-SORT [34] applies an additional network to extract target features, then utilizes cosine distances for matching besides motion consideration in SORT [3]. JDE [32], FairMOT [44], and Unicorn [38] further explore the architecture of appearance embedding and matching. ByteTrack [43] employs a robust detector based onYOLOX [12] and reuses low-confidence detections to enhance the association ability. Furthermore, OC-SORT [5] improves SORT [3] by rehabilitating lost targets. In recent years, as a trendy framework in vision tasks, some studies [35, 47] have also applied Transformers to match detection bounding boxes. Moreover, Dendorfer et al. [10] attempt to model pedestrian trajectories by leveraging more complex motion estimation methods (like S-GAN [14]) from the trajectory prediction task. + +The methods described above have powerful detection capabilities due to their robust detectors. However, although such methods have achieved outstanding performance in pedestrian tracking datasets, they are mediocre at dealing with more complex scenarios having irregular movements. These unforeseeable motion patterns will cause the trajec + +tory estimation and prediction module to fail. + +Tracking-by-Query usually does not require additional post-processing to associate detection results. Unlike the tracking-by-detection paradigm mentioned above, tracking-by-query methods apply the track query to decode the location of tracked objects progressively. + +Inspired by DETR-family [6], most of these methods [22, 42] leverage the learnable object query to perform newborn object detection, while the track query localizes the position of tracked objects. TransTrack [30] builds a siamese network for detection and tracking, then applies an IoU matching to produce newborn targets. TrackFormer [22] utilizes the same Transformer decoder for both detection and tracking, then employs a nonmaximum suppression (NMS) with a high IoU threshold to remove strongly overlapping duplicate bounding boxes. MOTR [42] builds an elegant and fully end-to-end Transformer for multi-object tracking. This paradigm performs excellently in dealing with irregular movements due to the flexibility of query-based design. Furthermore, MQT [17] employs different queries to represent one tracked object and cares more about class-agnostic tracking. + +However, current query-based methods typically exploit the information of adjacent frames (query [42] or feature [22] fusion). Although the track query can be continuously updated over time, most methods still do not explicitly exploit longer temporal information. Cai et al. [4] explore a large memory bank to benefit from time-related knowledge but suffer enormous storage costs. In order to use long-term information, we propose a long-term memory to stabilize the tracked object feature over time and a memory-attention layer for a more distinguishable representation. Our experiments further approve that this approach significantly improves association performance in MOT. + +# 3. Method + +# 3.1. Overview + +We propose the MeMOTR, a long-term memory-augmented Transformer for multi-object tracking. Different from most existing methods [22, 42] that only explicitly utilize the states of tracked objects between adjacent frames, our core contribution is to build a long-term memory (in Section 3.3) that maintains the long-term temporal feature for each tracked target, together with a temporal interaction module (TIM) that effectively injects the temporal information into subsequent tracking processes. + +Like most DETR-family methods [6], we use a ResNet-50 [15] backbone and a Transformer Encoder to produce the image feature of an input frame $I^t$ . As shown in Figure 1, the learnable detect query $Q_{det}$ is fed into the Detection Decoder $\mathcal{D}_{det}$ (in Section 3.2) to generate the detect embedding $E_{det}^{t}$ for the current frame. Afterward, by query + +![](images/0bd298b495f0935e5b2fbce12b108fdc8db7e6f6e91d78be73382ed509911d08.jpg) +Figure 1. Overview of MeMOTR. Like most DETR-based [6] methods, we exploit a ResNet-50 [15] backbone and a Transformer [31] Encoder to learn a 2D representation of an input image. We use different colors to indicate different tracked targets, and the learnable detect query $Q_{det}$ is illustrated in gray. Then the Detection Decoder $\mathcal{D}_{det}$ processes the detect query to generate the detect embedding $E_{det}^{t}$ , which aligns with the track embedding $E_{tck}^{t}$ from previous frames. Long-term memory is denoted as $M_{tck}^{t}$ . The initialization process in the blue dotted arrow will be applied to newborn objects. Our Long-Term Memory and Temporal Interaction Module is discussed in Section 3.3 and 3.4. More details are illustrated in Figure 2. + +ing the encoded image feature with $[E_{det}^{t}, E_{tck}^{t}]$ , the Transformer Joint Decoder $\mathcal{D}_{joint}$ produces the corresponding output $[\hat{O}_{det}^{t}, \hat{O}_{tck}^{t}]$ . For simplicity, we merge the newborn objects in $\hat{O}_{det}^{t}$ (yellow box) with tracked objects' output $\hat{O}_{tck}^{t}$ , denoted by $O_{tck}^{t}$ . Afterward, we predict the classification confidence $c_{i}^{t}$ and bounding box $b_{i}^{t}$ corresponding to the $i^{th}$ target from the output embeddings. Finally, we feed the output from adjacent frames $[O_{tck}^{t}, O_{tck}^{t-1}]$ and the long-term memory $M_{tck}^{t}$ into the Temporal Interaction Module, updating the subsequent track embedding $E_{tck}^{t+1}$ and long-term memory $M_{tck}^{t+1}$ . The details of our components will be elaborated in the following sections. + +# 3.2. Detection Decoder + +In the previous Transformer-based methods [22, 42], the learnable detect query and the previous track query are jointly input to Transformer Decoder from scratch. This simple idea extends the end-to-end detection Transformer [6] to multi-object tracking. Nonetheless, we argue that this design may cause misalignment between detect and track queries. As discussed in numerous works [6, 20], the learnable object query in DETR-family plays a role similar to a learnable anchor with little semantic information. On the other hand, track queries have specific semantic knowledge to resolve their category and bounding boxes since they are generated from the output of previous frames. + +Therefore, as illustrated in Figure 1, we split the original Transformer Decoder into two parts. The first decoder layer is used for detection, and the remaining five layers are used for joint detection and tracking. These two decoders have the same structure but different inputs. The Detection Decoder $\mathcal{D}_{det}$ takes the original learnable detect query $Q_{det}$ + +as input and generates the corresponding detect embedding $E_{det}^{t}$ , carrying enough semantic information to locate and classify the target roughly. After that, we concatenate the detect and track embedding together and feed them into the Joint Decoder $\mathcal{D}_{joint}$ . + +# 3.3. Long-Term Memory + +Unlike previous methods [17, 42] that only exploit adjacent frames' information, we explicitly introduce a long-term memory $M_{tck}^{t}$ to maintain longer temporal information for tracked targets. When a newborn object is detected, we initialize its long-term memory with the current output. + +It should be noted that in a video stream, objects only have minor deformation and movement in consecutive frames. Thus, we suppose the semantic feature of a tracked object changes only slightly in a short time. In the same way, our long-term memory should also update smoothly over time. Inspired by [28], we apply a simple but effective running average with exponentially decaying weights to update long-term memory $M_{tck}^{t}$ : + +$$ +\widetilde {M} _ {t c k} ^ {t + 1} = (1 - \lambda) M _ {t c k} ^ {t} + \lambda \cdot O _ {t c k} ^ {t}, \tag {1} +$$ + +where $\widetilde{M}_{tck}^{t+1}$ is the new long-term memory for the next frame. The memory update rate $\lambda$ is experimentally set to 0.01, following the assumption that the memory changes smoothly and consistently in consecutive frames. We also tried some other values in Table 7. + +# 3.4. Temporal Interaction Module + +Adaptive Aggregation for Temporal Enhancement. Issues such as blurring or occlusion are often seen in a video stream. An intuitive idea to solve this problem is using + +![](images/e8cc905e439a8df8d2c700ebade1c23e6395f2327f99e183856078f055e73f54.jpg) +Figure 2. Illustration of Temporal Interaction Module. $\widetilde{E}_{tck}^{t+1}$ and $\widetilde{M}_{tck}^{t+1}$ are the prediction of $E_{tck}^{t}$ and $M_{tck}^{t}$ for the next frame, respectively. + +multi-frame features to enhance the single-frame representation. Therefore, we fuse the outputs from two adjacent frames with an adaptive aggregation algorithm in our MeM-OTR. Due to occlusions and blurring, the output embedding $O_{tck}^{t}$ of the current frame may be unreliable. Thus, as illustrated in Figure 2, we generate a channel-wise weight $W_{tck}^{t}$ for each tracked instance to alleviate this problem: + +$$ +W _ {t c k} ^ {t} = \operatorname {S i g m o i d} \left(\operatorname {M L P} \left(O _ {t c k} ^ {t}\right)\right). \tag {2} +$$ + +We multiply this weight $W_{tck}^{t}$ with the current output $O_{tck}^{t}$ and then concatenate the result with $O_{tck}^{t-1}$ from the previous frame. Furthermore, we apply a two-layer MLP to produce the fusion outcome $\widetilde{O}_{tck}^{t}$ . This adaptive aggregation enhances the target representation with short-term temporal modeling. + +However, we do not use the above channel-wise weight for previous output $O_{tck}^{t-1}$ . As we will discuss in Section 3.5, there is a difference between $O_{tck}^{t}$ and $O_{tck}^{t-1}$ . During inference, we employ a score threshold $\tau_{tck}$ to guarantee that $O_{tck}^{t-1}$ is relatively reliable. Therefore, we input it entirely into the subsequent fusion step without the adaptive weight. + +Generate Track Embedding. As discussed in Section 3.1, we exploit the track embedding $E_{tck}^{t}$ to produce the location and category of each tracked target. Therefore, generating more reliable and distinguishable track embedding is the key to improving tracking performance. Our processing is illustrated in Figure 2. + +Since there are multiple similar objects in the same frame, we believe that learning more discriminative representations is also crucial to the tracker. Thus we employ a Multi-Head Attention [31] structure called memory-attention layer to achieve this interaction between different trajectories. Due to the reliability of long-term memory + +$M_{tck}^{t}$ , we use it as $K$ , and the aggregation $\hat{O}_{tck}^{t}$ and the output embedding $O_{tck}^{t}$ as $Q$ and $V$ , respectively. + +After that, we combine long-term memory $M_{tck}^{t}$ and the result of memory-attention layer using addition, then input into an FFN network to predict the subsequent track embedding $\widetilde{E}_{tck}^{t+1}$ . As shown in Equation (1), long-term memory is gradually changing over time. Therefore, by incorporating information from long-term memory, the track embedding $\widetilde{E}_{tck}^{t+1}$ avoids abrupt changes that may cause association mistakes in consecutive frames. This design significantly improves the performance of object association, corroborated by ablation experiments shown in Table 6. + +# 3.5. Inference Details + +At time step $t$ , we jointly input the learnable detect query $Q_{det}$ and track embedding $E_{tck}^{t}$ ( $E_{tck}^{0} = \emptyset$ ) into our model to produce detection and tracking results, respectively. The detection result with a confidence score of more than $\tau_{det}$ will transform into a newborn object. + +Target occlusion is a common issue in multi-object tracking task. If a tracked object is lost (confidence $\leq \tau_{tck}$ ) in the current frame, we do not directly remove its track embedding but mark it as inactive trajectory. Afterward, the inactive target will be removed entirely after $\mathcal{T}_{miss}$ frames. + +It is worth noting that we do not update the track embedding and long-term memory at every time step for each object. Instead, we choose to update those track embedding with high confidence. The choice of update threshold $\tau_{next}$ yields the following formulation for updating: + +$$ +\left[ E _ {i} ^ {t + 1}, M _ {i} ^ {t + 1} \right] = \left\{ \begin{array}{l l} \left[ \widetilde {E} _ {i} ^ {t + 1}, \widetilde {M} _ {i} ^ {t + 1} \right], & c _ {i} ^ {t} > \tau_ {\text {n e x t}} \\ \left[ E _ {i} ^ {t}, M _ {i} ^ {t} \right], & c _ {i} ^ {t} \leq \tau_ {\text {n e x t}} \end{array} , \right. \tag {3} +$$ + +where $i$ is the target index, $t$ is the frame index, and $c_i^t$ is the predicted classification confidence of the $i^{th}$ object at time step $t$ . $\widetilde{E}_i^{t + 1}$ and $\widetilde{M}_i^{t + 1}$ are the predictions of track embedding and long-term memory, generated by Temporal Interaction Module shown in Figure 2. For simplicity, we set $\tau_{det} = \tau_{tck} = \tau_{next} = 0.5$ in our experiments. $\mathcal{T}_{miss}$ is set to 30, 15 and 10 on DanceTrack, MOT17 and BDD100K, respectively. + +# 4. Experiments + +# 4.1. Datasets and Metrics + +Datasets. We mainly evaluate MeMOTR on the DanceTrack [29] dataset since they have more severe association challenges than traditional pedestrian tracking datasets. For a comprehensive evaluation, we also conduct experiments on MOT17 [23] and BDD100K [41]. + +Metrics. Because of providing a balanced way to measure both detection and association performance explicitly, + +we use Higher Order Metric for Evaluating Multi-Object Tracking (HOTA) [21] to evaluate our method, especially analyzing our memory mechanism using Association Accuracy (AssA). We also list the MOTA [2] and IDF1 [25] metrics in our experimental results. + +# 4.2. Implementation Details + +Following the settings in MOTR [42], we use several data augmentation methods, such as random resize and random crop. The shorter side of the input image is resized to 800, and the maximum size is restricted to 1536. + +We built MeMOTR upon DAB-Deformable-DETR [20] with a ResNet50 [15] backbone and initialize our model with the official DAB-Deformable-DETR [20] weights pretrained on the COCO [19] dataset. We suggest that the anchor-based position-prior from DAB-Deformable-DETR is quite effective due to the tracked box's smoothness in time and can be further exploited in future works. We also provide the results of our model based on Deformable-DETR [48] for fair comparison in Table 1. Our models are conducted on PyTorch with 8 NVIDIA Tesla V100 GPUs. By using PyTorch gradient checkpoint technology, we implement a memory-optimized version that can also be trained on NVIDIA GPUs with less than 10GB GPU memory. The batch size is set to 1 per GPU, and each batch contains a video clip with multiple frames. Within each clip, video frames are sampled with random intervals from 1 to 10. We use the AdamW optimizer with the initial learning rate of $2.0 \times 10^{-4}$ . During training, we filter out the tracked target lower than the score threshold $\tau_{update} = 0.5$ and IoU threshold $\tau_{IoU} = 0.5$ . + +On DanceTrack [29], we train MeMOTR for 18 epochs on the train set and drop the learning rate by a factor of 10 at the $12^{th}$ epoch. Firstly, we use two frames within a clip for training. And then increase the clip frames to 3, 4, and 5 at the $6^{th}$ , $10^{th}$ , and $14^{th}$ epochs, respectively. On MOT17 [23], due to the small train set (about 5K frames), it is easy to cause overfitting problems. Therefore, we add CrowdHuman [27] validation set to build a joint train set with MOT17 training data. CrowdHuman val set provides about 4K static images. Therefore, we apply random shifts from CenterTrack [46] to generate pseudo trajectories. Finally, we train MeMOTR for 130 epochs, and the learning rate decays by a factor of 10 at the $120^{th}$ epoch. The initial length of the training video clip is 2 and gradually increases to 3 and 4 at the $60^{th}$ and $100^{th}$ epochs, respectively. On BDD100K [41], we modify the sampling length at the $6^{th}$ and $10^{th}$ epochs and totally train 14 epochs while reducing the learning rate at the $12^{th}$ epoch. + +# 4.3. Comparison on the DanceTrack Dataset + +Since DanceTrack [29] is a dataset with various motions that cannot be modeled by classic linear motion estima + +
MethodsHOTADetAAssAMOTAIDF1
w/o extra data:
FairMOT [44]39.766.723.882.240.8
CenterTrack [46]41.878.122.686.835.7
TraDeS [36]43.374.525.486.241.2
TransTrack [30]45.575.927.588.445.2
ByteTrack [43]47.771.032.189.653.9
GTR [47]48.072.531.984.750.3
QDTrack [24]54.280.136.887.750.4
MOTR [42]54.273.540.279.751.5
OC-SORT [5]55.180.338.392.054.6
C-BIoU [40]60.681.345.491.661.6
MeMOTR* (ours)63.477.052.385.465.5
MeMOTR (ours)68.580.558.489.971.2
with extra data:
MT_IoT [39]66.784.153.094.070.6
MOTRv2 [45]69.983.059.091.971.7
+ +Table 1. Performance comparison with state-of-the-art methods on the DanceTrack [29] test set. Results for existing methods are from DanceTrack [29]. MeMOTR* means the result based on standard Deformable-DETR. + +tion [3, 5], it provides a better choice to verify our tracking performance, especially the association performance. + +We compare MeMOTR with the state-of-the-art methods on the DanceTrack [29] test set in Table 1. Our method achieves 68.5 HOTA and gains a vast lead on the AssA metric (58.4 AssA), even surpassing some methods [39] that use additional datasets for training. Due to the limitations of the linear motion estimation module, some tracking-by-detection methods, for example, ByteTrack [43], although they can achieve great detection results (71.0 DetA), still cannot handle complex object association problems (32.1 AssA). However, their MOTA metrics are still high because MOTA overemphasizes detection performance. + +Our temporal interaction module, shown in Figure 2, leverages temporal information gracefully and efficiently. Moreover, the separated detection decoder $\mathcal{D}_{det}$ discussed in Section 3.2 alleviates the conflicts between detection and tracking tasks. Therefore, we earn an impressive association performance (58.4 AssA and 71.2 IDF1) and competitive detection performance (80.5 DetA) compared with the state-of-the-art methods. We further prove our components' effectiveness in Section 4.6. + +# 4.4. Comparison on the MOT17 Dataset + +In order to make a comprehensive comparison, we also evaluate our method on the classic pedestrian tracking benchmark. Table 2 compares our method with state-of-the-art methods on the MOT17 [23] test set. + +Recent tracking-by-detection methods [40, 43] exploit robust detectors (like YOLOX [12]) to achieve really excel + +
MethodsHOTADetAAssAMOTAIDF1
CNN based:
Tracktor++ [1]44.844.945.153.552.3
CenterTrack [46]52.253.851.067.864.7
TraDeS [36]52.755.250.869.163.9
QDTrack [24]53.955.652.768.766.3
GTR [47]59.161.657.075.371.5
FairMOT [44]59.360.958.073.772.3
DeepSORT [34]61.263.159.778.074.5
SORT [3]63.064.262.280.178.2
ByteTrack [43]63.164.562.080.377.3
Quo Vadis [10]63.164.662.180.377.7
OC-SORT [5]63.263.263.478.077.5
C-BIoU [40]64.164.863.781.179.7
Transformer based:
TrackFormer [22]///74.168.0
TransTrack [30]54.161.647.974.563.9
TransCenter [37]54.560.149.773.262.2
MeMOT [4]56.9/55.272.569.0
MOTR [42]57.258.955.871.968.4
MeMOTR (ours)58.859.658.472.871.5
Hybird based:
MOTRv2 [45]62.063.860.678.675.0
+ +lent detection performance (up to 64.8 DetA). Since performance on MOT17 overemphasizes detection performance, these methods perform immensely well. In this regard, there is still a massive gap in the detection performance of Transformer-based methods [4, 42] because too many dense and small object predictions are involved. In addition, the joint query in a shared Transformer decoder produces tracking and detection simultaneously, which may cause internal conflicts. The detect query is inhibited by the track query in the self-attention [31] structure, limiting the ability to detect newborn objects, especially those close to tracked targets, and vice versa. Because of this, TransTrack [30] achieves significantly better detection performance (61.6 DetA) due to its siamese network structure. This architecture decouples tracking and detection to resolve the above conflict, but its simple post-processing matching algorithm decreases its association performance. + +On the other hand, we found that Transformer-based methods [42] suffer from serious overfitting problems in MOT17 [23] because of the tiny train set, which only contains about 5K frames. Although we use an additional CrowdHuman validation set for training mentioned in Section 4.2, severe overfitting still happens. Thus, we get $\sim 90.0$ HOTA and $\sim 95.0$ MOTA on the train set. However, + +Table 2. Performance comparison with state-of-the-art methods on the MOT17 [23] test set. The best performance among the Transformer-based methods is marked in **bold. MOTRv2** [45] is marked in **hybrid** since their YOLOX [12] proposals. + +
MethodmTETAmHOTAmLocAmAssocAmAssA
QDTrack [24]47.8/45.948.5/
DeepSORT [34]48.0/46.446.7/
MOTR [42]50.737.035.851.047.3
TETer [18]50.8/47.252.9/
MeMOTR (ours)53.640.438.156.752.6
+ +Table 3. Performance comparison on the BDD100K [41] val set. Results for existing methods are from [18]. + +![](images/797a29f04cbdbc905b218cf89a95352612119165dd8ad7231469aa95ba903aa4.jpg) + +![](images/a2b1f430ca88962de5828ac53574d1beb7f6f308c3a2747c5baedf5049c97f04.jpg) + +![](images/fd8abb219a02aed98c71c826320b4a221af423a51d3c18d6c95f4a611ab2f868.jpg) +Before Detection Decoder + +![](images/467bbfa2f84bb8895a042090eaa223f5d2c0f54019d1ee3ed1dac1fc0f84f55e.jpg) + +![](images/7cb2c7bfe0255d3c493adec232ac55c337c4a8915eee4f5e6518c8b7f0317ee3.jpg) +After Detection Decoder +Figure 3. Visualize the anchors of tracked and newborn targets before (left) and after (right) the separated detection decoder $\mathcal{D}_{\text{det}}$ . + +too much additional training data can lead to inductive bias toward static people. Therefore, we argue that the train set of MOT17 is too small to train our model completely. + +Eventually, our method slightly improves the performance on the MOT17 test set to 58.8 HOTA. We gain competitive detection accuracy (DetA) compared with other Transformer-based methods. In particular, we improved the performance of object association, which AssA and IDF1 metrics can reflect. As a method that also uses the memory mechanism, our MeMOTR achieves higher AssA and IDF1, surpassing MeMOT [4] by $3.2\%$ and $2.5\%$ , respectively. These experimental results further validate the effectiveness of our method. + +# 4.5. Comparison on the BDD100K Dataset + +In order to evaluate our method in multi-category scenarios, we also evaluate our method on the BDD100K [41] val set in Table 3. To better assess multi-class tracking performance, we leverage Tracking-Every-Thing Accuracy (TETA) metric for ranking as they did in BDD100K MOT Challenge 2023. We re-evaluate MOTR [42] on the new metrics using the official model for comparison. + +The results show that our method can generalize well to multi-class scenarios and achieve impressive performance + +
LDetHOTADetAAssAMOTAIDF1
062.174.352.283.165.6
163.974.655.083.467.1
263.273.854.381.965.8
+ +Table 4. Ablation experiments on the layers of the separate Detection Decoder, which is denoted as $\mathcal{L}_{\mathcal{D}_{det}}$ . + +
\(O_{t-1}\)\(W_{tck}^{t}\)HOTADetAAssAIDF1
62.373.952.764.6
✓62.474.552.564.6
✓62.774.453.165.3
✓✓63.974.655.067.1
+ +(53.6 TETA), especially in association (56.7 mAssocA), further demonstrating the effectiveness of our proposed method for associating targets. + +# 4.6. Ablation Study + +In this section, we study several components of our model, such as the long-term memory, adaptive aggregation, memory-attention layer, and separated detection decoder. Since our main contribution is a better utilization of temporal information, we choose to conduct ablation experiments on DanceTrack [29] due to its more severe object association challenges. On the other hand, DanceTrack [29] has more extensive training data to avoid severe overfitting (about $10 \times$ compared with MOT17 [23]). We train our model on the train set and evaluate it on the official val set. Detection Decoder. For joint tracking and detection, the tracking-by-query paradigm processes detect and track queries in a shared Transformer decoder from scratch. However, the track query has rich semantic content from the previous tracked targets, in contrast to the object query for detection. On the other hand, learnable detect anchors often cover a larger range to find potential targets. In contrast, the anchor of tracked object pays more attention to a small area where the target appeared in the previous frame. This may cause a large gap between the anchors of tracked and newborn objects, as we visualized in Figure 3 (left). + +In this paper, we apply a separated Transformer decoder layer to perform preliminary target detection. The output $E_{det}^{t}$ of this Detection Decoder $\mathcal{D}_{det}$ will be better aligned with the track embedding $E_{tck}^{t}$ generated by the previous frame to improve the tracking performance. We experimentally confirmed the effectiveness of this design, as shown in Table 4. Using only one separate Detection Decoder layer dramatically improves HOTA and AssA metrics by $1.8\%$ and $2.8\%$ , respectively. However, continuing to increase + +Table 5. Ablations on different designs of Adaptive Aggregation. + +
MtckattnHOTADetAAssAIDF1
naïve61.174.250.663.7
61.973.852.164.1
✓62.574.252.964.7
✓61.174.050.762.4
✓✓63.974.655.067.1
+ +Table 6. Ablation study of long-term memory $M_{tck}^{t}$ and memory-attention layer $attn$ . naive means a naive baseline with a single FFN for $O_{tck}^{t}$ to generate the track embedding $\tilde{E}_{tck}^{t+1}$ . + +
λHOTA↑DetA↑AssA↑IDF1↑IDsw ↓
0.00562.674.253.165.11383
0.0163.974.655.067.11237
0.0263.275.053.566.01213
0.0463.575.154.066.31295
+ +Table 7. Ablation study on the long-term memory update ratio $\lambda$ . + +the layers of the Detection Decoder will reduce the refinement steps of track embeddings, thus slightly weakening the association performance. Furthermore, we visualize the bounding boxes after Detection Decoder in Figure 3 (right). This indicates that $\mathcal{D}_{det}$ is able to locate objects roughly. + +Adaptive Aggregation. In Section 3.4, we design an adaptive aggregation, which dynamically fuses object features from adjacent frames. We ablate this structure in Table 5. + +The first two results only use the current output $O_{tck}^{t}$ to generate the temporal aggregation $\hat{O}_{tck}^{t}$ . In contrast, the next two lines fuse the previous output $\hat{O}_{tck}^{t-1}$ into $\hat{O}_{tck}^{t}$ . Introducing $O_{tck}^{t-1}$ provides additional object features from neighboring frames, thus improving tracking performance. We suppose this offers a complementary feature augmentation that can combat video ambiguity and uncertainty. + +Furthermore, we explore the impact of the dynamic weight $W_{tck}^{t}$ . As shown in Table 5, it only provides a little boost without $O_{tck}^{t-1}$ from the previous. We explain that dynamic $W_{tck}^{t}$ leads to missing information without complementary features from previous $O_{tck}^{t-1}$ . The result of the last row shows that utilizing both dynamic weight $W_{tck}^{t}$ and previous output $O_{tck}^{t-1}$ produces significantly better performance, with +2.6% HOTA and +2.3% AssA. + +Long-Term Memory. We propose a long-term memory in Section 3.3 to utilize longer temporal information and further inject it into subsequent track embedding to augment the object feature. + +We explore the impact of long-term memory $M_{tck}^{t}$ and show the experimental results in Table 6. For a more comprehensive comparison, we also experiment with another track embedding generation structure that removes the + +![](images/06118ad33e3e8445367062471ca789139ee714e0b0fdfeb9ed50bc90a851222b.jpg) +(a) w/o memory and w/o attention + +![](images/2c7aae48cfcd35add5b9787e25e8286df7947cae899639cf622a7857fb5224d5.jpg) +(b) $w / o$ memory and $w/$ attention + +![](images/b98afde71d03efafd8f3551aed53ec0ef612be966c2fc82c8707abc18c42c986.jpg) +(c) $w/$ memory and $w/o$ attention +Figure 4. Visualization of Track Embedding $E_{tck}^{t}$ (the first 50 frames in sequence dancetrack0063) from different structure designs by using t-Distributed Stochastic Neighbor Embedding (t-SNE). Track embeddings for different tracked targets (IDs) are marked in different colors and shapes. Our design 4(d) helps the model learn a more stable and distinguishable representation for the track embedding. Corresponding tracking performance is shown in Table 6. + +![](images/abc8835bc4f651d8b33671732b4adaac2cab12ea9a9aa987e80c6612f1a58049.jpg) +(d) $w/$ memory and $w/$ attention (ours) + +memory-attention layer by passing the temporal aggregation $\hat{O}_{tck}^{t}$ directly to an FFN network. + +Our experimental results show that utilizing long-term memory produces a better association performance, with $+0.8\%$ and $+4.3\%$ AssA for w/o and w/ memory-attention layer. The injection of long-term memory significantly stabilizes and augments the identity information of each track embedding, as visualized in Figure 4(c) and 4(d). + +Memory Attention. In Table 6, we also ablate memory-attention layer. It shows that by using memory-attention layer, our MeMOTR achieves much better performance (63.9 vs. 62.5 HOTA), especially improving AssA by $2.1\%$ . This attention layer establishes interactions between different trajectories that help the track embedding learns discriminative features. However, without long-term memory $M_{tck}^{t}$ , memory-attention layer produces worse performance $(-1.4\%)$ AssA and $-1.7\%$ IDF1. We explain that the track embedding without memory augmentation is unstable. Therefore, interacting with such unreliable information can be counterproductive, as visualized in Figure 4(b). + +Memory Update Rate. Here, we explored the impact of long-term memory update rate $\lambda$ on the tracking performance in Equation 1. As shown in Table 7, when progressively increasing the $\lambda_{L}$ from 0.005 to 0.04, our model achieves the highest HOTA score at $\lambda = 0.01$ while DetA score is decreasing slightly. We suggest the update rate $\lambda$ may be a hyperparameter that needs to be chosen according to different datasets. For example, scenarios with plenty of target non-rigid deformation may need a higher memory update rate to adapt to the rapidly changing features. + +# 4.7. Limitations + +Although our MeMOTR brings a significant improvement in association performance, detection performance is still a drawback, especially in crowded scenarios (like MOT17 [23]). During experiments, we observed that some + +times newborn objects are suppressed by tracked targets in the self-attention structure, which leads to reduced detection performance. Therefore, resolving this conflict is a crucial challenge for the joint tracking paradigm. This may help improve the detection capabilities, which can boost the overall tracking performance of the model, as studied in [45]. In addition, in pedestrian tracking, existing datasets are still limited in size and diversity. We suggest that training with other simulation datasets (like MOTSynth [11]) may alleviate the overfitting problem of our model and achieve better tracking performance. + +# 5. Conclusion + +We have proposed MeMOTR, an end-to-end long-term memory-augmented Transformer for multi-object tracking. Our method builds a stable long-term memory for each tracked object and exploits this memory to augment the representation of track embedding, thus improving its association performance. Furthermore, by leveraging a memory-attention layer, our model makes different targets more distinguishable. As a result, our approach achieves the state-of-the-art performance on MOT benchmarks, especially in scenes with irregular motion patterns. Extensive ablation experiments and visualizations demonstrate the effectiveness of our components. We hope that future work will pay more attention to the use of long-term temporal information for object tracking. + +Acknowledgements. This work is supported by National Key R&D Program of China (No. 2022ZD0160900), National Natural Science Foundation of China (No. 62076119, No. 61921006), Fundamental Research Funds for the Central Universities (No. 020214380091, No. 020214380099), and Collaborative Innovation Center of Novel Software Technology and Industrialization. Besides, Ruopeng Gao would like to thank Muyan Yang for her social support. + +# References + +[1] Philipp Bergmann, Tim Meinhardt, and Laura Leal-Taixe. Tracking without bells and whistles. In ICCV, pages 941-951. IEEE, 2019. 6 +[2] Keni Bernstein and Rainer Stiefelhagen. Evaluating multiple object tracking performance: The CLEAR MOT metrics. EURASIP J. Image Video Process., 2008, 2008. 5 +[3] Alex Bewley, ZongYuan Ge, Lionel Ott, Fabio Tozeto Ramos, and Ben Upcroft. Simple online and realtime tracking. In ICIP, pages 3464-3468. IEEE, 2016. 1, 2, 5, 6 +[4] Jiarui Cai, Mingze Xu, Wei Li, Yuanjun Xiong, Wei Xia, Zhuowen Tu, and Stefano Soatto. Memot: Multi-object tracking with memory. In CVPR, pages 8080-8090. IEEE, 2022. 2, 6 +[5] Jinkun Cao, Xinshuo Weng, Rawal Khirodkar, Jiangmiao Pang, and Kris Kitani. Observation-centric SORT: rethinking SORT for robust multi-object tracking. CoRR, abs/2203.14360, 2022. 1, 2, 5, 6 +[6] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In ECCV(1), volume 12346 of Lecture Notes in Computer Science, pages 213-229. Springer, 2020. 2, 3 +[7] Wongun Choi and Silvio Savarese. A unified framework for multi-target tracking and collective activity recognition. In ECCV (4), volume 7575 of Lecture Notes in Computer Science, pages 215-230. Springer, 2012. 1 +[8] Yutao Cui, Chenkai Zeng, Xiaoyu Zhao, Yichun Yang, Gangshan Wu, and Limin Wang. SportsMOT: A large multi-object tracking dataset in multiple sports scenes. In ICCV, 2023. 1 +[9] Patrick Dendorfer, Hamid Rezatofighi, Anton Milan, Javen Shi, Daniel Cremers, Ian D. Reid, Stefan Roth, Konrad Schindler, and Laura Leal-Taixe. MOT20: A benchmark for multi object tracking in crowded scenes. CoRR, abs/2003.09003, 2020. 2 +[10] Patrick Dendorfer, Vladimir Yugay, Aljosa Osep, and Laura Leal-Taixe. Quo vadis: Is trajectory forecasting the key towards long-term multi-object tracking? In NeurIPS, 2022. 2, 6 +[11] Matteo Fabbri, Guillem Brasó, Gianluca Maugeri, Orcun Cetintas, Riccardo Gasparini, Aljosa Osep, Simone Calderara, Laura Leal-Taixe, and Rita Cucchiara. Motsynth: How can synthetic data help pedestrian detection and tracking? In ICCV, pages 10829-10839. IEEE, 2021. 8 +[12] Zheng Ge, Songtao Liu, Feng Wang, Zeming Li, and Jian Sun. YOLOX: exceeding YOLO series in 2021. CoRR, abs/2107.08430, 2021. 1, 2, 5, 6 +[13] Silvio Giancola, Mohieddine Amine, Tarek Dghaily, and Bernard Ghanem. Socernet: A scalable dataset for action spotting in soccer videos. In CVPR Workshops, pages 1711-1721. Computer Vision Foundation / IEEE Computer Society, 2018. 1 +[14] Agrim Gupta, Justin Johnson, Li Fei-Fei, Silvio Savarese, and Alexandre Alahi. Social GAN: socially acceptable trajectories with generative adversarial networks. In CVPR, + +pages 2255-2264. Computer Vision Foundation / IEEE Computer Society, 2018. 2 +[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778. IEEE Computer Society, 2016. 2, 3, 5 +[16] Weiming Hu, Tieniu Tan, Liang Wang, and Stephen J. Maybank. A survey on visual surveillance of object motion and behaviors. IEEE Trans. Syst. Man Cybern. Part C, 34(3):334-352, 2004. 1 +[17] Bruno Korbar and Andrew Zisserman. End-to-end tracking with a multi-query transformer. CoRR, abs/2210.14601, 2022. 2, 3 +[18] Siyuan Li, Martin Danelljan, Henghui Ding, Thomas E. Huang, and Fisher Yu. Tracking every thing in the wild. In ECCV (22), volume 13682 of Lecture Notes in Computer Science, pages 498-515. Springer, 2022. 6 +[19] Tsung-Yi Lin, Michael Maire, Serge J. Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C. Lawrence Zitnick. Microsoft COCO: common objects in context. In ECCV (5), volume 8693 of Lecture Notes in Computer Science, pages 740-755. Springer, 2014. 5 +[20] Shilong Liu, Feng Li, Hao Zhang, Xiao Yang, Xianbiao Qi, Hang Su, Jun Zhu, and Lei Zhang. DAB-DETR: dynamic anchor boxes are better queries for DETR. In ICLR. OpenReview.net, 2022. 3, 5 +[21] Jonathon Luiten, Aljosa Osep, Patrick Dendorfer, Philip H. S. Torr, Andreas Geiger, Laura Leal-Taixe, and Bastian Leibe. HOTA: A higher order metric for evaluating multi-object tracking. Int. J. Comput. Vis., 129(2):548-578, 2021. 5 +[22] Tim Meinhardt, Alexander Kirillov, Laura Leal-Taixe, and Christoph Feichtenhofer. Trackformer: Multi-object tracking with transformers. In CVPR, pages 8834-8844. IEEE, 2022. 1, 2, 3, 6 +[23] Anton Milan, Laura Leal-Taixe, Ian D. Reid, Stefan Roth, and Konrad Schindler. MOT16: A benchmark for multi-object tracking. CoRR, abs/1603.00831, 2016. 1, 2, 4, 5, 6, 7, 8 +[24] Jiangmiao Pang, Linlu Qiu, Xia Li, Haofeng Chen, Qi Li, Trevor Darrell, and Fisher Yu. Quasi-dense similarity learning for multiple object tracking. In CVPR, pages 164-173. Computer Vision Foundation / IEEE, 2021. 5, 6 +[25] Ergys Ristani, Francesco Solera, Roger S. Zou, Rita Cucchiara, and Carlo Tomasi. Performance measures and a data set for multi-target, multi-camera tracking. In ECCV Workshops (2), volume 9914 of Lecture Notes in Computer Science, pages 17-35, 2016. 5 +[26] Ergys Ristani and Carlo Tomasi. Features for multi-target multi-camera tracking and re-identification. In CVPR, pages 6036–6046. Computer Vision Foundation / IEEE Computer Society, 2018. 1 +[27] Shuai Shao, Zijian Zhao, Boxun Li, Tete Xiao, Gang Yu, Xiangyu Zhang, and Jian Sun. Crowdhuman: A benchmark for detecting human in a crowd. CoRR, abs/1805.00123, 2018. 5 +[28] Chris Stauffer and W. Eric L. Grimson. Adaptive background mixture models for real-time tracking. In CVPR, pages 2246-2252. IEEE Computer Society, 1999. 1, 3 + +[29] Peize Sun, Jinkun Cao, Yi Jiang, Zehuan Yuan, Song Bai, Kris Kitani, and Ping Luo. Dancetrack: Multi-object tracking in uniform appearance and diverse motion. In CVPR, pages 20961-20970. IEEE, 2022. 1, 2, 4, 5, 7 +[30] Peize Sun, Yi Jiang, Rufeng Zhang, Enze Xie, Jinkun Cao, Xinting Hu, Tao Kong, Zehuan Yuan, Changhu Wang, and Ping Luo. Transtrack: Multiple-object tracking with transformer. CoRR, abs/2012.15460, 2020. 2, 5, 6 +[31] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In NIPS, pages 5998-6008, 2017. 3, 4, 6 +[32] Zhongdao Wang, Liang Zheng, Yixuan Liu, Yali Li, and Shengjin Wang. Towards real-time multi-object tracking. In ECCV (11), volume 12356 of Lecture Notes in Computer Science, pages 107-122. Springer, 2020. 1, 2 +[33] Greg Welch, Gary Bishop, et al. An introduction to the kalman filter. 1995. 2 +[34] Nicolai Wojke, Alex Bewley, and Dietrich Paulus. Simple online and realtime tracking with a deep association metric. In ICIP, pages 3645-3649. IEEE, 2017. 2, 6 +[35] Sanghyun Woo, Kwanyong Park, Seoul Wug Oh, In So Kweon, and Joon-Young Lee. Tracking by associating clips. In ECCV (25), volume 13685 of Lecture Notes in Computer Science, pages 129–145. Springer, 2022. 2 +[36] Jialian Wu, Jiale Cao, Liangchen Song, Yu Wang, Ming Yang, and Junsong Yuan. Track to detect and segment: An online multi-object tracker. In CVPR, pages 12352-12361. Computer Vision Foundation / IEEE, 2021. 5, 6 +[37] Yihong Xu, Yutong Ban, Guillaume Delorme, Chuang Gan, Daniela Rus, and Xavier Alameda-Pineda. Transcenter: Transformers with dense queries for multiple-object tracking. CoRR, abs/2103.15145, 2021. 6 +[38] Bin Yan, Yi Jiang, Peize Sun, Dong Wang, Zehuan Yuan, Ping Luo, and Huchuan Lu. Towards grand unification of object tracking. In ECCV (21), volume 13681 of Lecture Notes in Computer Science, pages 733-751. Springer, 2022. 2 +[39] Feng Yan, Zhiheng Li, Weixin Luo, Zequn jie, Fan Liang, Xiaolin Wei, and Lin Ma. Multiple object tracking challenge technical report for team mt_iot, 2022. 5 +[40] Fan Yang, Shigeyuki Odashima, Shoichi Masui, and Shan Jiang. Hard to track objects with irregular motions and similar appearances? make it easier by buffering the matching space. In WACV, pages 4788-4797. IEEE, 2023. 1, 5, 6 +[41] Fisher Yu, Haofeng Chen, Xin Wang, Wenqi Xian, Yingying Chen, Fangchen Liu, Vashisht Madhavan, and Trevor Darrell. BDD100K: A diverse driving dataset for heterogeneous multitask learning. In CVPR, pages 2633-2642. Computer Vision Foundation / IEEE, 2020. 2, 4, 5, 6 +[42] Fangao Zeng, Bin Dong, Yuang Zhang, Tiancai Wang, Xi-angyu Zhang, and Yichen Wei. MOTR: end-to-end multiple-object tracking with transformer. In ECCV (27), volume 13687 of Lecture Notes in Computer Science, pages 659–675. Springer, 2022. 1, 2, 3, 5, 6 +[43] Yifu Zhang, Peize Sun, Yi Jiang, Dongdong Yu, Fucheng Weng, Zehuan Yuan, Ping Luo, Wenyu Liu, and Xinggang + +Wang. Bytetrack: Multi-object tracking by associating every detection box. In ECCV (22), volume 13682 of Lecture Notes in Computer Science, pages 1-21. Springer, 2022. 1, 2, 5, 6 +[44] Yifu Zhang, Chunyu Wang, Xinggang Wang, Wenjun Zeng, and Wenyu Liu. Fairmot: On the fairness of detection and re-identification in multiple object tracking. Int. J. Comput. Vis., 129(11):3069-3087, 2021. 2, 5, 6 +[45] Yang Zhang, Tiancai Wang, and Xiangyu Zhang. Motrv2: Bootstrapping end-to-end multi-object tracking by pretrained object detectors, 2022. 5, 6, 8 +[46] Xingyi Zhou, Vladlen Koltun, and Philipp Krahenbuhl. Tracking objects as points. In ECCV (4), volume 12349 of Lecture Notes in Computer Science, pages 474-490. Springer, 2020. 5, 6 +[47] Xingyi Zhou, Tianwei Yin, Vladlen Koltun, and Philipp Krahenbihl. Global tracking transformers. In CVPR, pages 8761-8770. IEEE, 2022. 2, 5, 6 +[48] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable DETR: deformable transformers for end-to-end object detection. In ICLR. OpenReview.net, 2021. 5 \ No newline at end of file diff --git a/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/images.zip b/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..0c23cf326ff24bc5471e517325c2d3f9dfdb3e6b --- /dev/null +++ b/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:3c3b5e8adaede1d5cbe849bd90b1e52334fb4fa788125ad4438f1cb1737e3e29 +size 442616 diff --git a/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/layout.json b/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..d246590bb2260d903b42e6303a41ca55f63be026 --- /dev/null +++ b/2023/MeMOTR_ Long-Term Memory-Augmented Transformer for Multi-Object Tracking/layout.json @@ -0,0 +1,9603 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 118, + 103, + 477, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 118, + 103, + 477, + 140 + ], + "spans": [ + { + "bbox": [ + 118, + 103, + 477, + 140 + ], + "type": "text", + "content": "MeMOTR: Long-Term Memory-Augmented Transformer for Multi-Object Tracking" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 194, + 161, + 399, + 175 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 194, + 161, + 399, + 175 + ], + "spans": [ + { + "bbox": [ + 194, + 161, + 399, + 175 + ], + "type": "text", + "content": "Ruopeng Gao" + }, + { + "bbox": [ + 194, + 161, + 399, + 175 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 194, + 161, + 399, + 175 + ], + "type": "text", + "content": " Limin Wang" + }, + { + "bbox": [ + 194, + 161, + 399, + 175 + ], + "type": "inline_equation", + "content": "^{1,2,\\text{四}}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 65, + 175, + 529, + 190 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 175, + 529, + 190 + ], + "spans": [ + { + "bbox": [ + 65, + 175, + 529, + 190 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 65, + 175, + 529, + 190 + ], + "type": "text", + "content": "State Key Laboratory for Novel Software Technology, Nanjing University " + }, + { + "bbox": [ + 65, + 175, + 529, + 190 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 65, + 175, + 529, + 190 + ], + "type": "text", + "content": "Shanghai AI Lab" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 228, + 192, + 242 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 228, + 192, + 242 + ], + "spans": [ + { + "bbox": [ + 143, + 228, + 192, + 242 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 254, + 290, + 470 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 254, + 290, + 470 + ], + "spans": [ + { + "bbox": [ + 46, + 254, + 290, + 470 + ], + "type": "text", + "content": "As a video task, Multiple Object Tracking (MOT) is expected to capture temporal information of targets effectively. Unfortunately, most existing methods only explicitly exploit the object features between adjacent frames, while lacking the capacity to model long-term temporal information. In this paper, we propose MeMOTR, a long-term memory-augmented Transformer for multi-object tracking. Our method is able to make the same object's track embedding more stable and distinguishable by leveraging long-term memory injection with a customized memory-attention layer. This significantly improves the target association ability of our model. Experimental results on DanceTrack show that MeMOTR impressively surpasses the state-of-the-art method by " + }, + { + "bbox": [ + 46, + 254, + 290, + 470 + ], + "type": "inline_equation", + "content": "7.9\\%" + }, + { + "bbox": [ + 46, + 254, + 290, + 470 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 254, + 290, + 470 + ], + "type": "inline_equation", + "content": "13.0\\%" + }, + { + "bbox": [ + 46, + 254, + 290, + 470 + ], + "type": "text", + "content": " on HOTA and AssA metrics, respectively. Furthermore, our model also outperforms other Transformer-based methods on association performance on MOT17 and generalizes well on BDD100K. Code is available at https://github.com/MCG-NJU/MeMOTR." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 494, + 128, + 506 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 494, + 128, + 506 + ], + "spans": [ + { + "bbox": [ + 47, + 494, + 128, + 506 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 514, + 287, + 586 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 514, + 287, + 586 + ], + "spans": [ + { + "bbox": [ + 46, + 514, + 287, + 586 + ], + "type": "text", + "content": "Multi-Object Tracking (MOT) [8, 23, 29] aims to detect multiple objects and maintain their identities in a video stream. MOT can be applied to numerous downstream tasks, such as action recognition [7], behavior analysis [16], and so on. It is also an important technique for real-world applications, e.g., autonomous driving and surveillance." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 586, + 288, + 695 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 586, + 288, + 695 + ], + "spans": [ + { + "bbox": [ + 46, + 586, + 288, + 695 + ], + "type": "text", + "content": "According to the definition of MOT, this task can be formally divided into two parts: object detection and association. For a long time, pedestrian tracking datasets (like MOT17 [23]) have had mainstream domination in the community. However, these datasets have insufficient challenges in target association because of their almost linear motion pattern. Therefore, tracking-by-detection methods [5, 32, 43] achieve the state-of-the-art performance of MOT for several years. They first adopt a robust object de" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 218, + 547, + 385 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 218, + 547, + 385 + ], + "spans": [ + { + "bbox": [ + 304, + 218, + 547, + 385 + ], + "type": "text", + "content": "tector (e.g., YOLOX [12]) to independently localize the objects in each frame and associate them with IoU [3, 40] or ReID features [26]. However, associating targets becomes a critical challenge in some complex scenarios, like group dancers [29] and sports players [8, 13]. These similar appearances and erratic movements may cause existing methods to fail. Recently, Transformer-based tracking methods [22, 42] have introduced a new fully-end-to-end MOT paradigm. Through the interaction and progressive decoding of detect and track queries in Transformer, they simultaneously complete detection and tracking. This paradigm is expected to have greater potential for object association due to the flexibility of Transformer, especially in the above complex scenes." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 387, + 548, + 519 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 387, + 548, + 519 + ], + "spans": [ + { + "bbox": [ + 304, + 387, + 548, + 519 + ], + "type": "text", + "content": "Although these Transformer-based methods achieve excellent performance, they still struggle with some complicated issues, such as analogous appearances, irregular motion patterns, and long-term occlusions. We hypothesize that more intelligent leverage of temporal information can provide the tracker a more effective and robust representation for each tracked target, thereby relieving the above issues and boosting the tracking performance. Unfortunately, most previous methods [22, 42] only exploit the image or object features between two adjacent frames, which lacking the utilization of long-term temporal information." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 520, + 548, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 520, + 548, + 700 + ], + "spans": [ + { + "bbox": [ + 304, + 520, + 548, + 700 + ], + "type": "text", + "content": "Based on the analysis above, in this paper, we focus on leveraging temporal information by proposing a long-term Memory-augmented Multi-Object Tracking method with TRansformer, coined as MeMOTR. We exploit detect and track embeddings to localize newborn and tracked objects via a Transformer Decoder, respectively. Our model maintains a long-term memory with the exponential recursion update algorithm [28] for each tracked object. Afterward, we inject this memory into the track embedding, reducing its abrupt changes and thus improving the model association ability. As multiple tracked targets exist in a video stream, we apply a memory-attention layer to produce a more distinguishable representation. Besides, we present an adaptive aggregation to fuse the object feature from two adjacent frames to improve tracking robustness." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 317, + 701, + 545, + 714 + ], + "type": "text", + "content": "In addition, we argue that the learnable detection query" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 61, + 703, + 223, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 703, + 223, + 713 + ], + "spans": [ + { + "bbox": [ + 61, + 703, + 223, + 713 + ], + "type": "inline_equation", + "content": "\\boxtimes" + }, + { + "bbox": [ + 61, + 703, + 223, + 713 + ], + "type": "text", + "content": " : Corresponding author (lmwang@nju.edu.cn)." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "9901" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 191 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 191 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 191 + ], + "type": "text", + "content": "in DETR [6] has no semantic information about specific objects. However, the track query in Transformer-based MOT methods like MOTR [42] carries information about a tracked object. This difference will cause a semantic information gap and thus degrade the final tracking performance. Therefore, to overcome this issue, we use a light decoder to perform preliminary object detection, which outputs the detect embedding with specific semantics. Then we jointly input detect and track embeddings into the subsequent decoder to make MeMOTR tracking results more precise." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 192, + 288, + 312 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 192, + 288, + 312 + ], + "spans": [ + { + "bbox": [ + 46, + 192, + 288, + 312 + ], + "type": "text", + "content": "We mainly evaluate our method on the DanceTrack dataset [29] because of its serious association challenge. Experimental results show that our method achieves the state-of-the-art performance on this challenging DanceTrack dataset, especially on association metrics (e.g., AssA, IDF1). We also evaluate our model on the traditional pedestrian tracking dataset of MOT17 [23] and the multicategories tracking dataset of BDD100K [41]. In addition, we perform extensive ablation studies further demonstrate the effectiveness of our designs." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 323, + 134, + 335 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 323, + 134, + 335 + ], + "spans": [ + { + "bbox": [ + 47, + 323, + 134, + 335 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 342, + 287, + 390 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 342, + 287, + 390 + ], + "spans": [ + { + "bbox": [ + 46, + 342, + 287, + 390 + ], + "type": "text", + "content": "Tracking-by-Detection is a widely used MOT paradigm that has recently dominated the community. These methods always get trajectories by associating a given set of detections in a streaming video." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 390, + 288, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 390, + 288, + 641 + ], + "spans": [ + { + "bbox": [ + 46, + 390, + 288, + 641 + ], + "type": "text", + "content": "The objects in classic pedestrian tracking scenarios [9, 23] always have different appearances and regular motion patterns. Therefore, appearance matching and linear motion estimation are widely used to match targets in consecutive frames. SORT [3] uses the Intersection-over-Union (IoU) to match predictions of the Kalman filter [33] and detected boxes. Deep-SORT [34] applies an additional network to extract target features, then utilizes cosine distances for matching besides motion consideration in SORT [3]. JDE [32], FairMOT [44], and Unicorn [38] further explore the architecture of appearance embedding and matching. ByteTrack [43] employs a robust detector based onYOLOX [12] and reuses low-confidence detections to enhance the association ability. Furthermore, OC-SORT [5] improves SORT [3] by rehabilitating lost targets. In recent years, as a trendy framework in vision tasks, some studies [35, 47] have also applied Transformers to match detection bounding boxes. Moreover, Dendorfer et al. [10] attempt to model pedestrian trajectories by leveraging more complex motion estimation methods (like S-GAN [14]) from the trajectory prediction task." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 642, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 287, + 715 + ], + "type": "text", + "content": "The methods described above have powerful detection capabilities due to their robust detectors. However, although such methods have achieved outstanding performance in pedestrian tracking datasets, they are mediocre at dealing with more complex scenarios having irregular movements. These unforeseeable motion patterns will cause the trajec" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 72, + 489, + 84 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 489, + 84 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 489, + 84 + ], + "type": "text", + "content": "tory estimation and prediction module to fail." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 85, + 545, + 145 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 85, + 545, + 145 + ], + "spans": [ + { + "bbox": [ + 304, + 85, + 545, + 145 + ], + "type": "text", + "content": "Tracking-by-Query usually does not require additional post-processing to associate detection results. Unlike the tracking-by-detection paradigm mentioned above, tracking-by-query methods apply the track query to decode the location of tracked objects progressively." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 145, + 546, + 337 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 145, + 546, + 337 + ], + "spans": [ + { + "bbox": [ + 304, + 145, + 546, + 337 + ], + "type": "text", + "content": "Inspired by DETR-family [6], most of these methods [22, 42] leverage the learnable object query to perform newborn object detection, while the track query localizes the position of tracked objects. TransTrack [30] builds a siamese network for detection and tracking, then applies an IoU matching to produce newborn targets. TrackFormer [22] utilizes the same Transformer decoder for both detection and tracking, then employs a nonmaximum suppression (NMS) with a high IoU threshold to remove strongly overlapping duplicate bounding boxes. MOTR [42] builds an elegant and fully end-to-end Transformer for multi-object tracking. This paradigm performs excellently in dealing with irregular movements due to the flexibility of query-based design. Furthermore, MQT [17] employs different queries to represent one tracked object and cares more about class-agnostic tracking." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 338, + 547, + 482 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 338, + 547, + 482 + ], + "spans": [ + { + "bbox": [ + 304, + 338, + 547, + 482 + ], + "type": "text", + "content": "However, current query-based methods typically exploit the information of adjacent frames (query [42] or feature [22] fusion). Although the track query can be continuously updated over time, most methods still do not explicitly exploit longer temporal information. Cai et al. [4] explore a large memory bank to benefit from time-related knowledge but suffer enormous storage costs. In order to use long-term information, we propose a long-term memory to stabilize the tracked object feature over time and a memory-attention layer for a more distinguishable representation. Our experiments further approve that this approach significantly improves association performance in MOT." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 494, + 362, + 506 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 494, + 362, + 506 + ], + "spans": [ + { + "bbox": [ + 306, + 494, + 362, + 506 + ], + "type": "text", + "content": "3. Method" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 514, + 373, + 525 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 514, + 373, + 525 + ], + "spans": [ + { + "bbox": [ + 306, + 514, + 373, + 525 + ], + "type": "text", + "content": "3.1. Overview" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 533, + 545, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 545, + 640 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 545, + 640 + ], + "type": "text", + "content": "We propose the MeMOTR, a long-term memory-augmented Transformer for multi-object tracking. Different from most existing methods [22, 42] that only explicitly utilize the states of tracked objects between adjacent frames, our core contribution is to build a long-term memory (in Section 3.3) that maintains the long-term temporal feature for each tracked target, together with a temporal interaction module (TIM) that effectively injects the temporal information into subsequent tracking processes." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 642, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 545, + 715 + ], + "type": "text", + "content": "Like most DETR-family methods [6], we use a ResNet-50 [15] backbone and a Transformer Encoder to produce the image feature of an input frame " + }, + { + "bbox": [ + 304, + 642, + 545, + 715 + ], + "type": "inline_equation", + "content": "I^t" + }, + { + "bbox": [ + 304, + 642, + 545, + 715 + ], + "type": "text", + "content": ". As shown in Figure 1, the learnable detect query " + }, + { + "bbox": [ + 304, + 642, + 545, + 715 + ], + "type": "inline_equation", + "content": "Q_{det}" + }, + { + "bbox": [ + 304, + 642, + 545, + 715 + ], + "type": "text", + "content": " is fed into the Detection Decoder " + }, + { + "bbox": [ + 304, + 642, + 545, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{det}" + }, + { + "bbox": [ + 304, + 642, + 545, + 715 + ], + "type": "text", + "content": " (in Section 3.2) to generate the detect embedding " + }, + { + "bbox": [ + 304, + 642, + 545, + 715 + ], + "type": "inline_equation", + "content": "E_{det}^{t}" + }, + { + "bbox": [ + 304, + 642, + 545, + 715 + ], + "type": "text", + "content": " for the current frame. Afterward, by query" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "9902" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 74, + 541, + 220 + ], + "blocks": [ + { + "bbox": [ + 53, + 74, + 541, + 220 + ], + "lines": [ + { + "bbox": [ + 53, + 74, + 541, + 220 + ], + "spans": [ + { + "bbox": [ + 53, + 74, + 541, + 220 + ], + "type": "image", + "image_path": "0bd298b495f0935e5b2fbce12b108fdc8db7e6f6e91d78be73382ed509911d08.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "lines": [ + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "spans": [ + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "type": "text", + "content": "Figure 1. Overview of MeMOTR. Like most DETR-based [6] methods, we exploit a ResNet-50 [15] backbone and a Transformer [31] Encoder to learn a 2D representation of an input image. We use different colors to indicate different tracked targets, and the learnable detect query " + }, + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "type": "inline_equation", + "content": "Q_{det}" + }, + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "type": "text", + "content": " is illustrated in gray. Then the Detection Decoder " + }, + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{det}" + }, + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "type": "text", + "content": " processes the detect query to generate the detect embedding " + }, + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "type": "inline_equation", + "content": "E_{det}^{t}" + }, + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "type": "text", + "content": ", which aligns with the track embedding " + }, + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "type": "inline_equation", + "content": "E_{tck}^{t}" + }, + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "type": "text", + "content": " from previous frames. Long-term memory is denoted as " + }, + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "type": "inline_equation", + "content": "M_{tck}^{t}" + }, + { + "bbox": [ + 46, + 232, + 546, + 299 + ], + "type": "text", + "content": ". The initialization process in the blue dotted arrow will be applied to newborn objects. Our Long-Term Memory and Temporal Interaction Module is discussed in Section 3.3 and 3.4. More details are illustrated in Figure 2." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "spans": [ + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": "ing the encoded image feature with " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "[E_{det}^{t}, E_{tck}^{t}]" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": ", the Transformer Joint Decoder " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{joint}" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": " produces the corresponding output " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "[\\hat{O}_{det}^{t}, \\hat{O}_{tck}^{t}]" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": ". For simplicity, we merge the newborn objects in " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "\\hat{O}_{det}^{t}" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": " (yellow box) with tracked objects' output " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "\\hat{O}_{tck}^{t}" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": ", denoted by " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "O_{tck}^{t}" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": ". Afterward, we predict the classification confidence " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "c_{i}^{t}" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": " and bounding box " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "b_{i}^{t}" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": " corresponding to the " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "i^{th}" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": " target from the output embeddings. Finally, we feed the output from adjacent frames " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "[O_{tck}^{t}, O_{tck}^{t-1}]" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": " and the long-term memory " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "M_{tck}^{t}" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": " into the Temporal Interaction Module, updating the subsequent track embedding " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "E_{tck}^{t+1}" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": " and long-term memory " + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "inline_equation", + "content": "M_{tck}^{t+1}" + }, + { + "bbox": [ + 46, + 317, + 289, + 465 + ], + "type": "text", + "content": ". The details of our components will be elaborated in the following sections." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 477, + 156, + 488 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 477, + 156, + 488 + ], + "spans": [ + { + "bbox": [ + 47, + 477, + 156, + 488 + ], + "type": "text", + "content": "3.2. Detection Decoder" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 497, + 287, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 497, + 287, + 640 + ], + "spans": [ + { + "bbox": [ + 46, + 497, + 287, + 640 + ], + "type": "text", + "content": "In the previous Transformer-based methods [22, 42], the learnable detect query and the previous track query are jointly input to Transformer Decoder from scratch. This simple idea extends the end-to-end detection Transformer [6] to multi-object tracking. Nonetheless, we argue that this design may cause misalignment between detect and track queries. As discussed in numerous works [6, 20], the learnable object query in DETR-family plays a role similar to a learnable anchor with little semantic information. On the other hand, track queries have specific semantic knowledge to resolve their category and bounding boxes since they are generated from the output of previous frames." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 642, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 288, + 714 + ], + "type": "text", + "content": "Therefore, as illustrated in Figure 1, we split the original Transformer Decoder into two parts. The first decoder layer is used for detection, and the remaining five layers are used for joint detection and tracking. These two decoders have the same structure but different inputs. The Detection Decoder " + }, + { + "bbox": [ + 46, + 642, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{det}" + }, + { + "bbox": [ + 46, + 642, + 288, + 714 + ], + "type": "text", + "content": " takes the original learnable detect query " + }, + { + "bbox": [ + 46, + 642, + 288, + 714 + ], + "type": "inline_equation", + "content": "Q_{det}" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 318, + 546, + 378 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 318, + 546, + 378 + ], + "spans": [ + { + "bbox": [ + 305, + 318, + 546, + 378 + ], + "type": "text", + "content": "as input and generates the corresponding detect embedding " + }, + { + "bbox": [ + 305, + 318, + 546, + 378 + ], + "type": "inline_equation", + "content": "E_{det}^{t}" + }, + { + "bbox": [ + 305, + 318, + 546, + 378 + ], + "type": "text", + "content": ", carrying enough semantic information to locate and classify the target roughly. After that, we concatenate the detect and track embedding together and feed them into the Joint Decoder " + }, + { + "bbox": [ + 305, + 318, + 546, + 378 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{joint}" + }, + { + "bbox": [ + 305, + 318, + 546, + 378 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 385, + 424, + 399 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 385, + 424, + 399 + ], + "spans": [ + { + "bbox": [ + 306, + 385, + 424, + 399 + ], + "type": "text", + "content": "3.3. Long-Term Memory" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 403, + 545, + 464 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 403, + 545, + 464 + ], + "spans": [ + { + "bbox": [ + 304, + 403, + 545, + 464 + ], + "type": "text", + "content": "Unlike previous methods [17, 42] that only exploit adjacent frames' information, we explicitly introduce a long-term memory " + }, + { + "bbox": [ + 304, + 403, + 545, + 464 + ], + "type": "inline_equation", + "content": "M_{tck}^{t}" + }, + { + "bbox": [ + 304, + 403, + 545, + 464 + ], + "type": "text", + "content": " to maintain longer temporal information for tracked targets. When a newborn object is detected, we initialize its long-term memory with the current output." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 464, + 546, + 561 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 464, + 546, + 561 + ], + "spans": [ + { + "bbox": [ + 304, + 464, + 546, + 561 + ], + "type": "text", + "content": "It should be noted that in a video stream, objects only have minor deformation and movement in consecutive frames. Thus, we suppose the semantic feature of a tracked object changes only slightly in a short time. In the same way, our long-term memory should also update smoothly over time. Inspired by [28], we apply a simple but effective running average with exponentially decaying weights to update long-term memory " + }, + { + "bbox": [ + 304, + 464, + 546, + 561 + ], + "type": "inline_equation", + "content": "M_{tck}^{t}" + }, + { + "bbox": [ + 304, + 464, + 546, + 561 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 356, + 568, + 545, + 585 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 356, + 568, + 545, + 585 + ], + "spans": [ + { + "bbox": [ + 356, + 568, + 545, + 585 + ], + "type": "interline_equation", + "content": "\\widetilde {M} _ {t c k} ^ {t + 1} = (1 - \\lambda) M _ {t c k} ^ {t} + \\lambda \\cdot O _ {t c k} ^ {t}, \\tag {1}", + "image_path": "226f067d1f00ffee8e7fb7e0a14f2947b9d783be251738b5ca46a846fd296404.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 590, + 545, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 590, + 545, + 651 + ], + "spans": [ + { + "bbox": [ + 304, + 590, + 545, + 651 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 590, + 545, + 651 + ], + "type": "inline_equation", + "content": "\\widetilde{M}_{tck}^{t+1}" + }, + { + "bbox": [ + 304, + 590, + 545, + 651 + ], + "type": "text", + "content": " is the new long-term memory for the next frame. The memory update rate " + }, + { + "bbox": [ + 304, + 590, + 545, + 651 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 590, + 545, + 651 + ], + "type": "text", + "content": " is experimentally set to 0.01, following the assumption that the memory changes smoothly and consistently in consecutive frames. We also tried some other values in Table 7." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 659, + 468, + 672 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 659, + 468, + 672 + ], + "spans": [ + { + "bbox": [ + 306, + 659, + 468, + 672 + ], + "type": "text", + "content": "3.4. Temporal Interaction Module" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 677, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 546, + 714 + ], + "type": "text", + "content": "Adaptive Aggregation for Temporal Enhancement. Issues such as blurring or occlusion are often seen in a video stream. An intuitive idea to solve this problem is using" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "9903" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 86, + 70, + 249, + 238 + ], + "blocks": [ + { + "bbox": [ + 86, + 70, + 249, + 238 + ], + "lines": [ + { + "bbox": [ + 86, + 70, + 249, + 238 + ], + "spans": [ + { + "bbox": [ + 86, + 70, + 249, + 238 + ], + "type": "image", + "image_path": "e8cc905e439a8df8d2c700ebade1c23e6395f2327f99e183856078f055e73f54.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 247, + 287, + 285 + ], + "lines": [ + { + "bbox": [ + 46, + 247, + 287, + 285 + ], + "spans": [ + { + "bbox": [ + 46, + 247, + 287, + 285 + ], + "type": "text", + "content": "Figure 2. Illustration of Temporal Interaction Module. " + }, + { + "bbox": [ + 46, + 247, + 287, + 285 + ], + "type": "inline_equation", + "content": "\\widetilde{E}_{tck}^{t+1}" + }, + { + "bbox": [ + 46, + 247, + 287, + 285 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 247, + 287, + 285 + ], + "type": "inline_equation", + "content": "\\widetilde{M}_{tck}^{t+1}" + }, + { + "bbox": [ + 46, + 247, + 287, + 285 + ], + "type": "text", + "content": " are the prediction of " + }, + { + "bbox": [ + 46, + 247, + 287, + 285 + ], + "type": "inline_equation", + "content": "E_{tck}^{t}" + }, + { + "bbox": [ + 46, + 247, + 287, + 285 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 247, + 287, + 285 + ], + "type": "inline_equation", + "content": "M_{tck}^{t}" + }, + { + "bbox": [ + 46, + 247, + 287, + 285 + ], + "type": "text", + "content": " for the next frame, respectively." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 304, + 286, + 388 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 304, + 286, + 388 + ], + "spans": [ + { + "bbox": [ + 46, + 304, + 286, + 388 + ], + "type": "text", + "content": "multi-frame features to enhance the single-frame representation. Therefore, we fuse the outputs from two adjacent frames with an adaptive aggregation algorithm in our MeM-OTR. Due to occlusions and blurring, the output embedding " + }, + { + "bbox": [ + 46, + 304, + 286, + 388 + ], + "type": "inline_equation", + "content": "O_{tck}^{t}" + }, + { + "bbox": [ + 46, + 304, + 286, + 388 + ], + "type": "text", + "content": " of the current frame may be unreliable. Thus, as illustrated in Figure 2, we generate a channel-wise weight " + }, + { + "bbox": [ + 46, + 304, + 286, + 388 + ], + "type": "inline_equation", + "content": "W_{tck}^{t}" + }, + { + "bbox": [ + 46, + 304, + 286, + 388 + ], + "type": "text", + "content": " for each tracked instance to alleviate this problem:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 101, + 400, + 287, + 415 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 101, + 400, + 287, + 415 + ], + "spans": [ + { + "bbox": [ + 101, + 400, + 287, + 415 + ], + "type": "interline_equation", + "content": "W _ {t c k} ^ {t} = \\operatorname {S i g m o i d} \\left(\\operatorname {M L P} \\left(O _ {t c k} ^ {t}\\right)\\right). \\tag {2}", + "image_path": "7d14ee9ab48ed6d325056e74ad34520a46d76dfe843ef47a96da5e0e3c71436b.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 419, + 287, + 491 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 419, + 287, + 491 + ], + "spans": [ + { + "bbox": [ + 46, + 419, + 287, + 491 + ], + "type": "text", + "content": "We multiply this weight " + }, + { + "bbox": [ + 46, + 419, + 287, + 491 + ], + "type": "inline_equation", + "content": "W_{tck}^{t}" + }, + { + "bbox": [ + 46, + 419, + 287, + 491 + ], + "type": "text", + "content": " with the current output " + }, + { + "bbox": [ + 46, + 419, + 287, + 491 + ], + "type": "inline_equation", + "content": "O_{tck}^{t}" + }, + { + "bbox": [ + 46, + 419, + 287, + 491 + ], + "type": "text", + "content": " and then concatenate the result with " + }, + { + "bbox": [ + 46, + 419, + 287, + 491 + ], + "type": "inline_equation", + "content": "O_{tck}^{t-1}" + }, + { + "bbox": [ + 46, + 419, + 287, + 491 + ], + "type": "text", + "content": " from the previous frame. Furthermore, we apply a two-layer MLP to produce the fusion outcome " + }, + { + "bbox": [ + 46, + 419, + 287, + 491 + ], + "type": "inline_equation", + "content": "\\widetilde{O}_{tck}^{t}" + }, + { + "bbox": [ + 46, + 419, + 287, + 491 + ], + "type": "text", + "content": ". This adaptive aggregation enhances the target representation with short-term temporal modeling." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "spans": [ + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "type": "text", + "content": "However, we do not use the above channel-wise weight for previous output " + }, + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "type": "inline_equation", + "content": "O_{tck}^{t-1}" + }, + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "type": "text", + "content": ". As we will discuss in Section 3.5, there is a difference between " + }, + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "type": "inline_equation", + "content": "O_{tck}^{t}" + }, + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "type": "inline_equation", + "content": "O_{tck}^{t-1}" + }, + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "type": "text", + "content": ". During inference, we employ a score threshold " + }, + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "type": "inline_equation", + "content": "\\tau_{tck}" + }, + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "type": "text", + "content": " to guarantee that " + }, + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "type": "inline_equation", + "content": "O_{tck}^{t-1}" + }, + { + "bbox": [ + 46, + 491, + 287, + 564 + ], + "type": "text", + "content": " is relatively reliable. Therefore, we input it entirely into the subsequent fusion step without the adaptive weight." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 570, + 287, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 287, + 640 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 287, + 640 + ], + "type": "text", + "content": "Generate Track Embedding. As discussed in Section 3.1, we exploit the track embedding " + }, + { + "bbox": [ + 46, + 570, + 287, + 640 + ], + "type": "inline_equation", + "content": "E_{tck}^{t}" + }, + { + "bbox": [ + 46, + 570, + 287, + 640 + ], + "type": "text", + "content": " to produce the location and category of each tracked target. Therefore, generating more reliable and distinguishable track embedding is the key to improving tracking performance. Our processing is illustrated in Figure 2." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "type": "text", + "content": "Since there are multiple similar objects in the same frame, we believe that learning more discriminative representations is also crucial to the tracker. Thus we employ a Multi-Head Attention [31] structure called memory-attention layer to achieve this interaction between different trajectories. Due to the reliability of long-term memory" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "spans": [ + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "inline_equation", + "content": "M_{tck}^{t}" + }, + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "text", + "content": ", we use it as " + }, + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "text", + "content": ", and the aggregation " + }, + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "inline_equation", + "content": "\\hat{O}_{tck}^{t}" + }, + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "text", + "content": " and the output embedding " + }, + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "inline_equation", + "content": "O_{tck}^{t}" + }, + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "inline_equation", + "content": "V" + }, + { + "bbox": [ + 305, + 71, + 545, + 96 + ], + "type": "text", + "content": ", respectively." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 97, + 545, + 216 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 97, + 545, + 216 + ], + "spans": [ + { + "bbox": [ + 305, + 97, + 545, + 216 + ], + "type": "text", + "content": "After that, we combine long-term memory " + }, + { + "bbox": [ + 305, + 97, + 545, + 216 + ], + "type": "inline_equation", + "content": "M_{tck}^{t}" + }, + { + "bbox": [ + 305, + 97, + 545, + 216 + ], + "type": "text", + "content": " and the result of memory-attention layer using addition, then input into an FFN network to predict the subsequent track embedding " + }, + { + "bbox": [ + 305, + 97, + 545, + 216 + ], + "type": "inline_equation", + "content": "\\widetilde{E}_{tck}^{t+1}" + }, + { + "bbox": [ + 305, + 97, + 545, + 216 + ], + "type": "text", + "content": ". As shown in Equation (1), long-term memory is gradually changing over time. Therefore, by incorporating information from long-term memory, the track embedding " + }, + { + "bbox": [ + 305, + 97, + 545, + 216 + ], + "type": "inline_equation", + "content": "\\widetilde{E}_{tck}^{t+1}" + }, + { + "bbox": [ + 305, + 97, + 545, + 216 + ], + "type": "text", + "content": " avoids abrupt changes that may cause association mistakes in consecutive frames. This design significantly improves the performance of object association, corroborated by ablation experiments shown in Table 6." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 224, + 408, + 235 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 224, + 408, + 235 + ], + "spans": [ + { + "bbox": [ + 306, + 224, + 408, + 235 + ], + "type": "text", + "content": "3.5. Inference Details" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "spans": [ + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "type": "text", + "content": "At time step " + }, + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "type": "text", + "content": ", we jointly input the learnable detect query " + }, + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "type": "inline_equation", + "content": "Q_{det}" + }, + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "type": "text", + "content": " and track embedding " + }, + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "type": "inline_equation", + "content": "E_{tck}^{t}" + }, + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "type": "text", + "content": " (" + }, + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "type": "inline_equation", + "content": "E_{tck}^{0} = \\emptyset" + }, + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "type": "text", + "content": ") into our model to produce detection and tracking results, respectively. The detection result with a confidence score of more than " + }, + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "type": "inline_equation", + "content": "\\tau_{det}" + }, + { + "bbox": [ + 305, + 243, + 545, + 302 + ], + "type": "text", + "content": " will transform into a newborn object." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 302, + 545, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 302, + 545, + 361 + ], + "spans": [ + { + "bbox": [ + 305, + 302, + 545, + 361 + ], + "type": "text", + "content": "Target occlusion is a common issue in multi-object tracking task. If a tracked object is lost (confidence " + }, + { + "bbox": [ + 305, + 302, + 545, + 361 + ], + "type": "inline_equation", + "content": "\\leq \\tau_{tck}" + }, + { + "bbox": [ + 305, + 302, + 545, + 361 + ], + "type": "text", + "content": ") in the current frame, we do not directly remove its track embedding but mark it as inactive trajectory. Afterward, the inactive target will be removed entirely after " + }, + { + "bbox": [ + 305, + 302, + 545, + 361 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_{miss}" + }, + { + "bbox": [ + 305, + 302, + 545, + 361 + ], + "type": "text", + "content": " frames." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 363, + 545, + 422 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 363, + 545, + 422 + ], + "spans": [ + { + "bbox": [ + 305, + 363, + 545, + 422 + ], + "type": "text", + "content": "It is worth noting that we do not update the track embedding and long-term memory at every time step for each object. Instead, we choose to update those track embedding with high confidence. The choice of update threshold " + }, + { + "bbox": [ + 305, + 363, + 545, + 422 + ], + "type": "inline_equation", + "content": "\\tau_{next}" + }, + { + "bbox": [ + 305, + 363, + 545, + 422 + ], + "type": "text", + "content": " yields the following formulation for updating:" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 321, + 441, + 545, + 473 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 321, + 441, + 545, + 473 + ], + "spans": [ + { + "bbox": [ + 321, + 441, + 545, + 473 + ], + "type": "interline_equation", + "content": "\\left[ E _ {i} ^ {t + 1}, M _ {i} ^ {t + 1} \\right] = \\left\\{ \\begin{array}{l l} \\left[ \\widetilde {E} _ {i} ^ {t + 1}, \\widetilde {M} _ {i} ^ {t + 1} \\right], & c _ {i} ^ {t} > \\tau_ {\\text {n e x t}} \\\\ \\left[ E _ {i} ^ {t}, M _ {i} ^ {t} \\right], & c _ {i} ^ {t} \\leq \\tau_ {\\text {n e x t}} \\end{array} , \\right. \\tag {3}", + "image_path": "f90871fca3367cb724e63297faebc25d8468a7bf57006c17a7d3d56b09c1e5ee.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "spans": [ + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "text", + "content": " is the target index, " + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "text", + "content": " is the frame index, and " + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "inline_equation", + "content": "c_i^t" + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "text", + "content": " is the predicted classification confidence of the " + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "inline_equation", + "content": "i^{th}" + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "text", + "content": " object at time step " + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "inline_equation", + "content": "\\widetilde{E}_i^{t + 1}" + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "inline_equation", + "content": "\\widetilde{M}_i^{t + 1}" + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "text", + "content": " are the predictions of track embedding and long-term memory, generated by Temporal Interaction Module shown in Figure 2. For simplicity, we set " + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "inline_equation", + "content": "\\tau_{det} = \\tau_{tck} = \\tau_{next} = 0.5" + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "text", + "content": " in our experiments. " + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_{miss}" + }, + { + "bbox": [ + 305, + 483, + 545, + 580 + ], + "type": "text", + "content": " is set to 30, 15 and 10 on DanceTrack, MOT17 and BDD100K, respectively." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 591, + 387, + 604 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 591, + 387, + 604 + ], + "spans": [ + { + "bbox": [ + 306, + 591, + 387, + 604 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 611, + 427, + 622 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 611, + 427, + 622 + ], + "spans": [ + { + "bbox": [ + 306, + 611, + 427, + 622 + ], + "type": "text", + "content": "4.1. Datasets and Metrics" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 629, + 545, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 629, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 305, + 629, + 545, + 689 + ], + "type": "text", + "content": "Datasets. We mainly evaluate MeMOTR on the DanceTrack [29] dataset since they have more severe association challenges than traditional pedestrian tracking datasets. For a comprehensive evaluation, we also conduct experiments on MOT17 [23] and BDD100K [41]." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "content": "Metrics. Because of providing a balanced way to measure both detection and association performance explicitly," + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "9904" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 288, + 133 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 288, + 133 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 288, + 133 + ], + "type": "text", + "content": "we use Higher Order Metric for Evaluating Multi-Object Tracking (HOTA) [21] to evaluate our method, especially analyzing our memory mechanism using Association Accuracy (AssA). We also list the MOTA [2] and IDF1 [25] metrics in our experimental results." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 140, + 180, + 153 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 140, + 180, + 153 + ], + "spans": [ + { + "bbox": [ + 47, + 140, + 180, + 153 + ], + "type": "text", + "content": "4.2. Implementation Details" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 159, + 286, + 206 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 159, + 286, + 206 + ], + "spans": [ + { + "bbox": [ + 46, + 159, + 286, + 206 + ], + "type": "text", + "content": "Following the settings in MOTR [42], we use several data augmentation methods, such as random resize and random crop. The shorter side of the input image is resized to 800, and the maximum size is restricted to 1536." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 207, + 287, + 446 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 207, + 287, + 446 + ], + "spans": [ + { + "bbox": [ + 46, + 207, + 287, + 446 + ], + "type": "text", + "content": "We built MeMOTR upon DAB-Deformable-DETR [20] with a ResNet50 [15] backbone and initialize our model with the official DAB-Deformable-DETR [20] weights pretrained on the COCO [19] dataset. We suggest that the anchor-based position-prior from DAB-Deformable-DETR is quite effective due to the tracked box's smoothness in time and can be further exploited in future works. We also provide the results of our model based on Deformable-DETR [48] for fair comparison in Table 1. Our models are conducted on PyTorch with 8 NVIDIA Tesla V100 GPUs. By using PyTorch gradient checkpoint technology, we implement a memory-optimized version that can also be trained on NVIDIA GPUs with less than 10GB GPU memory. The batch size is set to 1 per GPU, and each batch contains a video clip with multiple frames. Within each clip, video frames are sampled with random intervals from 1 to 10. We use the AdamW optimizer with the initial learning rate of " + }, + { + "bbox": [ + 46, + 207, + 287, + 446 + ], + "type": "inline_equation", + "content": "2.0 \\times 10^{-4}" + }, + { + "bbox": [ + 46, + 207, + 287, + 446 + ], + "type": "text", + "content": ". During training, we filter out the tracked target lower than the score threshold " + }, + { + "bbox": [ + 46, + 207, + 287, + 446 + ], + "type": "inline_equation", + "content": "\\tau_{update} = 0.5" + }, + { + "bbox": [ + 46, + 207, + 287, + 446 + ], + "type": "text", + "content": " and IoU threshold " + }, + { + "bbox": [ + 46, + 207, + 287, + 446 + ], + "type": "inline_equation", + "content": "\\tau_{IoU} = 0.5" + }, + { + "bbox": [ + 46, + 207, + 287, + 446 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "spans": [ + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "text", + "content": "On DanceTrack [29], we train MeMOTR for 18 epochs on the train set and drop the learning rate by a factor of 10 at the " + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "inline_equation", + "content": "12^{th}" + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "text", + "content": " epoch. Firstly, we use two frames within a clip for training. And then increase the clip frames to 3, 4, and 5 at the " + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "inline_equation", + "content": "6^{th}" + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "inline_equation", + "content": "10^{th}" + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "inline_equation", + "content": "14^{th}" + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "text", + "content": " epochs, respectively. On MOT17 [23], due to the small train set (about 5K frames), it is easy to cause overfitting problems. Therefore, we add CrowdHuman [27] validation set to build a joint train set with MOT17 training data. CrowdHuman val set provides about 4K static images. Therefore, we apply random shifts from CenterTrack [46] to generate pseudo trajectories. Finally, we train MeMOTR for 130 epochs, and the learning rate decays by a factor of 10 at the " + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "inline_equation", + "content": "120^{th}" + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "text", + "content": " epoch. The initial length of the training video clip is 2 and gradually increases to 3 and 4 at the " + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "inline_equation", + "content": "60^{th}" + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "inline_equation", + "content": "100^{th}" + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "text", + "content": " epochs, respectively. On BDD100K [41], we modify the sampling length at the " + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "inline_equation", + "content": "6^{th}" + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "inline_equation", + "content": "10^{th}" + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "text", + "content": " epochs and totally train 14 epochs while reducing the learning rate at the " + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "inline_equation", + "content": "12^{th}" + }, + { + "bbox": [ + 46, + 447, + 287, + 662 + ], + "type": "text", + "content": " epoch." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 670, + 257, + 683 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 670, + 257, + 683 + ], + "spans": [ + { + "bbox": [ + 47, + 670, + 257, + 683 + ], + "type": "text", + "content": "4.3. Comparison on the DanceTrack Dataset" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 689, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 286, + 712 + ], + "type": "text", + "content": "Since DanceTrack [29] is a dataset with various motions that cannot be modeled by classic linear motion estima" + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 318, + 71, + 535, + 277 + ], + "blocks": [ + { + "bbox": [ + 318, + 71, + 535, + 277 + ], + "lines": [ + { + "bbox": [ + 318, + 71, + 535, + 277 + ], + "spans": [ + { + "bbox": [ + 318, + 71, + 535, + 277 + ], + "type": "table", + "html": "
MethodsHOTADetAAssAMOTAIDF1
w/o extra data:
FairMOT [44]39.766.723.882.240.8
CenterTrack [46]41.878.122.686.835.7
TraDeS [36]43.374.525.486.241.2
TransTrack [30]45.575.927.588.445.2
ByteTrack [43]47.771.032.189.653.9
GTR [47]48.072.531.984.750.3
QDTrack [24]54.280.136.887.750.4
MOTR [42]54.273.540.279.751.5
OC-SORT [5]55.180.338.392.054.6
C-BIoU [40]60.681.345.491.661.6
MeMOTR* (ours)63.477.052.385.465.5
MeMOTR (ours)68.580.558.489.971.2
with extra data:
MT_IoT [39]66.784.153.094.070.6
MOTRv2 [45]69.983.059.091.971.7
", + "image_path": "d808aeb85350d52c346e84e144656e0592fc4335415b902e2bd316092b86c74a.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 286, + 545, + 329 + ], + "lines": [ + { + "bbox": [ + 305, + 286, + 545, + 329 + ], + "spans": [ + { + "bbox": [ + 305, + 286, + 545, + 329 + ], + "type": "text", + "content": "Table 1. Performance comparison with state-of-the-art methods on the DanceTrack [29] test set. Results for existing methods are from DanceTrack [29]. MeMOTR* means the result based on standard Deformable-DETR." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 305, + 349, + 545, + 373 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 349, + 545, + 373 + ], + "spans": [ + { + "bbox": [ + 305, + 349, + 545, + 373 + ], + "type": "text", + "content": "tion [3, 5], it provides a better choice to verify our tracking performance, especially the association performance." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 373, + 545, + 505 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 373, + 545, + 505 + ], + "spans": [ + { + "bbox": [ + 304, + 373, + 545, + 505 + ], + "type": "text", + "content": "We compare MeMOTR with the state-of-the-art methods on the DanceTrack [29] test set in Table 1. Our method achieves 68.5 HOTA and gains a vast lead on the AssA metric (58.4 AssA), even surpassing some methods [39] that use additional datasets for training. Due to the limitations of the linear motion estimation module, some tracking-by-detection methods, for example, ByteTrack [43], although they can achieve great detection results (71.0 DetA), still cannot handle complex object association problems (32.1 AssA). However, their MOTA metrics are still high because MOTA overemphasizes detection performance." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 506, + 545, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 506, + 545, + 613 + ], + "spans": [ + { + "bbox": [ + 304, + 506, + 545, + 613 + ], + "type": "text", + "content": "Our temporal interaction module, shown in Figure 2, leverages temporal information gracefully and efficiently. Moreover, the separated detection decoder " + }, + { + "bbox": [ + 304, + 506, + 545, + 613 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{det}" + }, + { + "bbox": [ + 304, + 506, + 545, + 613 + ], + "type": "text", + "content": " discussed in Section 3.2 alleviates the conflicts between detection and tracking tasks. Therefore, we earn an impressive association performance (58.4 AssA and 71.2 IDF1) and competitive detection performance (80.5 DetA) compared with the state-of-the-art methods. We further prove our components' effectiveness in Section 4.6." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 622, + 495, + 634 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 622, + 495, + 634 + ], + "spans": [ + { + "bbox": [ + 306, + 622, + 495, + 634 + ], + "type": "text", + "content": "4.4. Comparison on the MOT17 Dataset" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 641, + 545, + 688 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 641, + 545, + 688 + ], + "spans": [ + { + "bbox": [ + 305, + 641, + 545, + 688 + ], + "type": "text", + "content": "In order to make a comprehensive comparison, we also evaluate our method on the classic pedestrian tracking benchmark. Table 2 compares our method with state-of-the-art methods on the MOT17 [23] test set." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": "Recent tracking-by-detection methods [40, 43] exploit robust detectors (like YOLOX [12]) to achieve really excel" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "9905" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 60, + 71, + 276, + 349 + ], + "blocks": [ + { + "bbox": [ + 60, + 71, + 276, + 349 + ], + "lines": [ + { + "bbox": [ + 60, + 71, + 276, + 349 + ], + "spans": [ + { + "bbox": [ + 60, + 71, + 276, + 349 + ], + "type": "table", + "html": "
MethodsHOTADetAAssAMOTAIDF1
CNN based:
Tracktor++ [1]44.844.945.153.552.3
CenterTrack [46]52.253.851.067.864.7
TraDeS [36]52.755.250.869.163.9
QDTrack [24]53.955.652.768.766.3
GTR [47]59.161.657.075.371.5
FairMOT [44]59.360.958.073.772.3
DeepSORT [34]61.263.159.778.074.5
SORT [3]63.064.262.280.178.2
ByteTrack [43]63.164.562.080.377.3
Quo Vadis [10]63.164.662.180.377.7
OC-SORT [5]63.263.263.478.077.5
C-BIoU [40]64.164.863.781.179.7
Transformer based:
TrackFormer [22]///74.168.0
TransTrack [30]54.161.647.974.563.9
TransCenter [37]54.560.149.773.262.2
MeMOT [4]56.9/55.272.569.0
MOTR [42]57.258.955.871.968.4
MeMOTR (ours)58.859.658.472.871.5
Hybird based:
MOTRv2 [45]62.063.860.678.675.0
", + "image_path": "2f8180d156f524c649c4da7d569cc3746ea8b5dec0c3558a00c9bbff08c3d35f.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 424, + 287, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 424, + 287, + 628 + ], + "spans": [ + { + "bbox": [ + 46, + 424, + 287, + 628 + ], + "type": "text", + "content": "lent detection performance (up to 64.8 DetA). Since performance on MOT17 overemphasizes detection performance, these methods perform immensely well. In this regard, there is still a massive gap in the detection performance of Transformer-based methods [4, 42] because too many dense and small object predictions are involved. In addition, the joint query in a shared Transformer decoder produces tracking and detection simultaneously, which may cause internal conflicts. The detect query is inhibited by the track query in the self-attention [31] structure, limiting the ability to detect newborn objects, especially those close to tracked targets, and vice versa. Because of this, TransTrack [30] achieves significantly better detection performance (61.6 DetA) due to its siamese network structure. This architecture decouples tracking and detection to resolve the above conflict, but its simple post-processing matching algorithm decreases its association performance." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 629, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 288, + 713 + ], + "type": "text", + "content": "On the other hand, we found that Transformer-based methods [42] suffer from serious overfitting problems in MOT17 [23] because of the tiny train set, which only contains about 5K frames. Although we use an additional CrowdHuman validation set for training mentioned in Section 4.2, severe overfitting still happens. Thus, we get " + }, + { + "bbox": [ + 46, + 629, + 288, + 713 + ], + "type": "inline_equation", + "content": "\\sim 90.0" + }, + { + "bbox": [ + 46, + 629, + 288, + 713 + ], + "type": "text", + "content": " HOTA and " + }, + { + "bbox": [ + 46, + 629, + 288, + 713 + ], + "type": "inline_equation", + "content": "\\sim 95.0" + }, + { + "bbox": [ + 46, + 629, + 288, + 713 + ], + "type": "text", + "content": " MOTA on the train set. However," + } + ] + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 309, + 71, + 543, + 152 + ], + "blocks": [ + { + "bbox": [ + 47, + 357, + 287, + 401 + ], + "lines": [ + { + "bbox": [ + 47, + 357, + 287, + 401 + ], + "spans": [ + { + "bbox": [ + 47, + 357, + 287, + 401 + ], + "type": "text", + "content": "Table 2. Performance comparison with state-of-the-art methods on the MOT17 [23] test set. The best performance among the Transformer-based methods is marked in **bold. MOTRv2** [45] is marked in **hybrid** since their YOLOX [12] proposals." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 309, + 71, + 543, + 152 + ], + "lines": [ + { + "bbox": [ + 309, + 71, + 543, + 152 + ], + "spans": [ + { + "bbox": [ + 309, + 71, + 543, + 152 + ], + "type": "table", + "html": "
MethodmTETAmHOTAmLocAmAssocAmAssA
QDTrack [24]47.8/45.948.5/
DeepSORT [34]48.0/46.446.7/
MOTR [42]50.737.035.851.047.3
TETer [18]50.8/47.252.9/
MeMOTR (ours)53.640.438.156.752.6
", + "image_path": "0a8ec96c5a0f804d6a8918a6596f445c89a282128fb6055b5096fe967315f037.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 306, + 159, + 545, + 182 + ], + "lines": [ + { + "bbox": [ + 306, + 159, + 545, + 182 + ], + "spans": [ + { + "bbox": [ + 306, + 159, + 545, + 182 + ], + "type": "text", + "content": "Table 3. Performance comparison on the BDD100K [41] val set. Results for existing methods are from [18]." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "text" + }, + { + "type": "image", + "bbox": [ + 324, + 194, + 425, + 261 + ], + "blocks": [ + { + "bbox": [ + 324, + 194, + 425, + 261 + ], + "lines": [ + { + "bbox": [ + 324, + 194, + 425, + 261 + ], + "spans": [ + { + "bbox": [ + 324, + 194, + 425, + 261 + ], + "type": "image", + "image_path": "797a29f04cbdbc905b218cf89a95352612119165dd8ad7231469aa95ba903aa4.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 428, + 194, + 527, + 261 + ], + "blocks": [ + { + "bbox": [ + 428, + 194, + 527, + 261 + ], + "lines": [ + { + "bbox": [ + 428, + 194, + 527, + 261 + ], + "spans": [ + { + "bbox": [ + 428, + 194, + 527, + 261 + ], + "type": "image", + "image_path": "a2b1f430ca88962de5828ac53574d1beb7f6f308c3a2747c5baedf5049c97f04.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 324, + 266, + 424, + 332 + ], + "blocks": [ + { + "bbox": [ + 324, + 266, + 424, + 332 + ], + "lines": [ + { + "bbox": [ + 324, + 266, + 424, + 332 + ], + "spans": [ + { + "bbox": [ + 324, + 266, + 424, + 332 + ], + "type": "image", + "image_path": "fd8abb219a02aed98c71c826320b4a221af423a51d3c18d6c95f4a611ab2f868.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 329, + 334, + 417, + 342 + ], + "lines": [ + { + "bbox": [ + 329, + 334, + 417, + 342 + ], + "spans": [ + { + "bbox": [ + 329, + 334, + 417, + 342 + ], + "type": "text", + "content": "Before Detection Decoder" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 428, + 266, + 527, + 332 + ], + "blocks": [ + { + "bbox": [ + 428, + 266, + 527, + 332 + ], + "lines": [ + { + "bbox": [ + 428, + 266, + 527, + 332 + ], + "spans": [ + { + "bbox": [ + 428, + 266, + 527, + 332 + ], + "type": "image", + "image_path": "467bbfa2f84bb8895a042090eaa223f5d2c0f54019d1ee3ed1dac1fc0f84f55e.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 328, + 346, + 525, + 362 + ], + "blocks": [ + { + "bbox": [ + 436, + 334, + 518, + 342 + ], + "lines": [ + { + "bbox": [ + 436, + 334, + 518, + 342 + ], + "spans": [ + { + "bbox": [ + 436, + 334, + 518, + 342 + ], + "type": "text", + "content": "After Detection Decoder" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 328, + 346, + 525, + 362 + ], + "lines": [ + { + "bbox": [ + 328, + 346, + 525, + 362 + ], + "spans": [ + { + "bbox": [ + 328, + 346, + 525, + 362 + ], + "type": "image", + "image_path": "7cb2c7bfe0255d3c493adec232ac55c337c4a8915eee4f5e6518c8b7f0317ee3.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 376, + 545, + 399 + ], + "lines": [ + { + "bbox": [ + 305, + 376, + 545, + 399 + ], + "spans": [ + { + "bbox": [ + 305, + 376, + 545, + 399 + ], + "type": "text", + "content": "Figure 3. Visualize the anchors of tracked and newborn targets before (left) and after (right) the separated detection decoder " + }, + { + "bbox": [ + 305, + 376, + 545, + 399 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{\\text{det}}" + }, + { + "bbox": [ + 305, + 376, + 545, + 399 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 420, + 545, + 456 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 420, + 545, + 456 + ], + "spans": [ + { + "bbox": [ + 304, + 420, + 545, + 456 + ], + "type": "text", + "content": "too much additional training data can lead to inductive bias toward static people. Therefore, we argue that the train set of MOT17 is too small to train our model completely." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 456, + 545, + 575 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 456, + 545, + 575 + ], + "spans": [ + { + "bbox": [ + 304, + 456, + 545, + 575 + ], + "type": "text", + "content": "Eventually, our method slightly improves the performance on the MOT17 test set to 58.8 HOTA. We gain competitive detection accuracy (DetA) compared with other Transformer-based methods. In particular, we improved the performance of object association, which AssA and IDF1 metrics can reflect. As a method that also uses the memory mechanism, our MeMOTR achieves higher AssA and IDF1, surpassing MeMOT [4] by " + }, + { + "bbox": [ + 304, + 456, + 545, + 575 + ], + "type": "inline_equation", + "content": "3.2\\%" + }, + { + "bbox": [ + 304, + 456, + 545, + 575 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 456, + 545, + 575 + ], + "type": "inline_equation", + "content": "2.5\\%" + }, + { + "bbox": [ + 304, + 456, + 545, + 575 + ], + "type": "text", + "content": ", respectively. These experimental results further validate the effectiveness of our method." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 586, + 507, + 598 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 586, + 507, + 598 + ], + "spans": [ + { + "bbox": [ + 306, + 586, + 507, + 598 + ], + "type": "text", + "content": "4.5. Comparison on the BDD100K Dataset" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 605, + 545, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 545, + 689 + ], + "type": "text", + "content": "In order to evaluate our method in multi-category scenarios, we also evaluate our method on the BDD100K [41] val set in Table 3. To better assess multi-class tracking performance, we leverage Tracking-Every-Thing Accuracy (TETA) metric for ranking as they did in BDD100K MOT Challenge 2023. We re-evaluate MOTR [42] on the new metrics using the official model for comparison." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "content": "The results show that our method can generalize well to multi-class scenarios and achieve impressive performance" + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "9906" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 65, + 70, + 271, + 129 + ], + "blocks": [ + { + "bbox": [ + 65, + 70, + 271, + 129 + ], + "lines": [ + { + "bbox": [ + 65, + 70, + 271, + 129 + ], + "spans": [ + { + "bbox": [ + 65, + 70, + 271, + 129 + ], + "type": "table", + "html": "
LDetHOTADetAAssAMOTAIDF1
062.174.352.283.165.6
163.974.655.083.467.1
263.273.854.381.965.8
", + "image_path": "3d2fe92024c9107fe52b2176dd7dc9d68fbe5b63a42cb0b5fa94209bf8015a89.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 69, + 170, + 266, + 251 + ], + "blocks": [ + { + "bbox": [ + 47, + 137, + 287, + 161 + ], + "lines": [ + { + "bbox": [ + 47, + 137, + 287, + 161 + ], + "spans": [ + { + "bbox": [ + 47, + 137, + 287, + 161 + ], + "type": "text", + "content": "Table 4. Ablation experiments on the layers of the separate Detection Decoder, which is denoted as " + }, + { + "bbox": [ + 47, + 137, + 287, + 161 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathcal{D}_{det}}" + }, + { + "bbox": [ + 47, + 137, + 287, + 161 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 69, + 170, + 266, + 251 + ], + "lines": [ + { + "bbox": [ + 69, + 170, + 266, + 251 + ], + "spans": [ + { + "bbox": [ + 69, + 170, + 266, + 251 + ], + "type": "table", + "html": "
\\(O_{t-1}\\)\\(W_{tck}^{t}\\)HOTADetAAssAIDF1
62.373.952.764.6
✓62.474.552.564.6
✓62.774.453.165.3
✓✓63.974.655.067.1
", + "image_path": "86e70dc4f9c6b232d2edef98ef02183e25a72cc0cc52181702c1ae6e62bb83a5.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 290, + 287, + 327 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 290, + 287, + 327 + ], + "spans": [ + { + "bbox": [ + 47, + 290, + 287, + 327 + ], + "type": "text", + "content": "(53.6 TETA), especially in association (56.7 mAssocA), further demonstrating the effectiveness of our proposed method for associating targets." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 335, + 141, + 347 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 335, + 141, + 347 + ], + "spans": [ + { + "bbox": [ + 47, + 335, + 141, + 347 + ], + "type": "text", + "content": "4.6. Ablation Study" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 354, + 287, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 354, + 287, + 605 + ], + "spans": [ + { + "bbox": [ + 46, + 354, + 287, + 605 + ], + "type": "text", + "content": "In this section, we study several components of our model, such as the long-term memory, adaptive aggregation, memory-attention layer, and separated detection decoder. Since our main contribution is a better utilization of temporal information, we choose to conduct ablation experiments on DanceTrack [29] due to its more severe object association challenges. On the other hand, DanceTrack [29] has more extensive training data to avoid severe overfitting (about " + }, + { + "bbox": [ + 46, + 354, + 287, + 605 + ], + "type": "inline_equation", + "content": "10 \\times" + }, + { + "bbox": [ + 46, + 354, + 287, + 605 + ], + "type": "text", + "content": " compared with MOT17 [23]). We train our model on the train set and evaluate it on the official val set. Detection Decoder. For joint tracking and detection, the tracking-by-query paradigm processes detect and track queries in a shared Transformer decoder from scratch. However, the track query has rich semantic content from the previous tracked targets, in contrast to the object query for detection. On the other hand, learnable detect anchors often cover a larger range to find potential targets. In contrast, the anchor of tracked object pays more attention to a small area where the target appeared in the previous frame. This may cause a large gap between the anchors of tracked and newborn objects, as we visualized in Figure 3 (left)." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "content": "In this paper, we apply a separated Transformer decoder layer to perform preliminary target detection. The output " + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "inline_equation", + "content": "E_{det}^{t}" + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "content": " of this Detection Decoder " + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{det}" + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "content": " will be better aligned with the track embedding " + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "inline_equation", + "content": "E_{tck}^{t}" + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "content": " generated by the previous frame to improve the tracking performance. We experimentally confirmed the effectiveness of this design, as shown in Table 4. Using only one separate Detection Decoder layer dramatically improves HOTA and AssA metrics by " + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "inline_equation", + "content": "1.8\\%" + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "inline_equation", + "content": "2.8\\%" + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "content": ", respectively. However, continuing to increase" + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 330, + 70, + 525, + 167 + ], + "blocks": [ + { + "bbox": [ + 47, + 259, + 282, + 270 + ], + "lines": [ + { + "bbox": [ + 47, + 259, + 282, + 270 + ], + "spans": [ + { + "bbox": [ + 47, + 259, + 282, + 270 + ], + "type": "text", + "content": "Table 5. Ablations on different designs of Adaptive Aggregation." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 330, + 70, + 525, + 167 + ], + "lines": [ + { + "bbox": [ + 330, + 70, + 525, + 167 + ], + "spans": [ + { + "bbox": [ + 330, + 70, + 525, + 167 + ], + "type": "table", + "html": "
MtckattnHOTADetAAssAIDF1
naïve61.174.250.663.7
61.973.852.164.1
✓62.574.252.964.7
✓61.174.050.762.4
✓✓63.974.655.067.1
", + "image_path": "03d075e878851d5cd94f563403fbefd3c05f085e1f48422a8d19b7ed27f2037e.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 331, + 221, + 523, + 293 + ], + "blocks": [ + { + "bbox": [ + 305, + 176, + 547, + 210 + ], + "lines": [ + { + "bbox": [ + 305, + 176, + 547, + 210 + ], + "spans": [ + { + "bbox": [ + 305, + 176, + 547, + 210 + ], + "type": "text", + "content": "Table 6. Ablation study of long-term memory " + }, + { + "bbox": [ + 305, + 176, + 547, + 210 + ], + "type": "inline_equation", + "content": "M_{tck}^{t}" + }, + { + "bbox": [ + 305, + 176, + 547, + 210 + ], + "type": "text", + "content": " and memory-attention layer " + }, + { + "bbox": [ + 305, + 176, + 547, + 210 + ], + "type": "inline_equation", + "content": "attn" + }, + { + "bbox": [ + 305, + 176, + 547, + 210 + ], + "type": "text", + "content": ". naive means a naive baseline with a single FFN for " + }, + { + "bbox": [ + 305, + 176, + 547, + 210 + ], + "type": "inline_equation", + "content": "O_{tck}^{t}" + }, + { + "bbox": [ + 305, + 176, + 547, + 210 + ], + "type": "text", + "content": " to generate the track embedding " + }, + { + "bbox": [ + 305, + 176, + 547, + 210 + ], + "type": "inline_equation", + "content": "\\tilde{E}_{tck}^{t+1}" + }, + { + "bbox": [ + 305, + 176, + 547, + 210 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 331, + 221, + 523, + 293 + ], + "lines": [ + { + "bbox": [ + 331, + 221, + 523, + 293 + ], + "spans": [ + { + "bbox": [ + 331, + 221, + 523, + 293 + ], + "type": "table", + "html": "
λHOTA↑DetA↑AssA↑IDF1↑IDsw ↓
0.00562.674.253.165.11383
0.0163.974.655.067.11237
0.0263.275.053.566.01213
0.0463.575.154.066.31295
", + "image_path": "ebb820529191996db3bf7b04c7591385dbf0c231419c14a6ad16227472d018d5.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 300, + 541, + 312 + ], + "lines": [ + { + "bbox": [ + 306, + 300, + 541, + 312 + ], + "spans": [ + { + "bbox": [ + 306, + 300, + 541, + 312 + ], + "type": "text", + "content": "Table 7. Ablation study on the long-term memory update ratio " + }, + { + "bbox": [ + 306, + 300, + 541, + 312 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 306, + 300, + 541, + 312 + ], + "type": "text", + "content": " ." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 334, + 545, + 394 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 334, + 545, + 394 + ], + "spans": [ + { + "bbox": [ + 304, + 334, + 545, + 394 + ], + "type": "text", + "content": "the layers of the Detection Decoder will reduce the refinement steps of track embeddings, thus slightly weakening the association performance. Furthermore, we visualize the bounding boxes after Detection Decoder in Figure 3 (right). This indicates that " + }, + { + "bbox": [ + 304, + 334, + 545, + 394 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{det}" + }, + { + "bbox": [ + 304, + 334, + 545, + 394 + ], + "type": "text", + "content": " is able to locate objects roughly." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 396, + 545, + 430 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 396, + 545, + 430 + ], + "spans": [ + { + "bbox": [ + 304, + 396, + 545, + 430 + ], + "type": "text", + "content": "Adaptive Aggregation. In Section 3.4, we design an adaptive aggregation, which dynamically fuses object features from adjacent frames. We ablate this structure in Table 5." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "spans": [ + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "type": "text", + "content": "The first two results only use the current output " + }, + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "type": "inline_equation", + "content": "O_{tck}^{t}" + }, + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "type": "text", + "content": " to generate the temporal aggregation " + }, + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "type": "inline_equation", + "content": "\\hat{O}_{tck}^{t}" + }, + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "type": "text", + "content": ". In contrast, the next two lines fuse the previous output " + }, + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "type": "inline_equation", + "content": "\\hat{O}_{tck}^{t-1}" + }, + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "type": "text", + "content": " into " + }, + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "type": "inline_equation", + "content": "\\hat{O}_{tck}^{t}" + }, + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "type": "text", + "content": ". Introducing " + }, + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "type": "inline_equation", + "content": "O_{tck}^{t-1}" + }, + { + "bbox": [ + 304, + 432, + 545, + 518 + ], + "type": "text", + "content": " provides additional object features from neighboring frames, thus improving tracking performance. We suppose this offers a complementary feature augmentation that can combat video ambiguity and uncertainty." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "spans": [ + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "text", + "content": "Furthermore, we explore the impact of the dynamic weight " + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "inline_equation", + "content": "W_{tck}^{t}" + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "text", + "content": ". As shown in Table 5, it only provides a little boost without " + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "inline_equation", + "content": "O_{tck}^{t-1}" + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "text", + "content": " from the previous. We explain that dynamic " + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "inline_equation", + "content": "W_{tck}^{t}" + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "text", + "content": " leads to missing information without complementary features from previous " + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "inline_equation", + "content": "O_{tck}^{t-1}" + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "text", + "content": ". The result of the last row shows that utilizing both dynamic weight " + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "inline_equation", + "content": "W_{tck}^{t}" + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "text", + "content": " and previous output " + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "inline_equation", + "content": "O_{tck}^{t-1}" + }, + { + "bbox": [ + 304, + 519, + 545, + 615 + ], + "type": "text", + "content": " produces significantly better performance, with +2.6% HOTA and +2.3% AssA." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 616, + 545, + 664 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 616, + 545, + 664 + ], + "spans": [ + { + "bbox": [ + 304, + 616, + 545, + 664 + ], + "type": "text", + "content": "Long-Term Memory. We propose a long-term memory in Section 3.3 to utilize longer temporal information and further inject it into subsequent track embedding to augment the object feature." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "We explore the impact of long-term memory " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "M_{tck}^{t}" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": " and show the experimental results in Table 6. For a more comprehensive comparison, we also experiment with another track embedding generation structure that removes the" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "9907" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 78, + 167, + 192 + ], + "blocks": [ + { + "bbox": [ + 53, + 78, + 167, + 192 + ], + "lines": [ + { + "bbox": [ + 53, + 78, + 167, + 192 + ], + "spans": [ + { + "bbox": [ + 53, + 78, + 167, + 192 + ], + "type": "image", + "image_path": "06118ad33e3e8445367062471ca789139ee714e0b0fdfeb9ed50bc90a851222b.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 55, + 199, + 167, + 209 + ], + "lines": [ + { + "bbox": [ + 55, + 199, + 167, + 209 + ], + "spans": [ + { + "bbox": [ + 55, + 199, + 167, + 209 + ], + "type": "text", + "content": "(a) w/o memory and w/o attention" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 176, + 78, + 291, + 192 + ], + "blocks": [ + { + "bbox": [ + 176, + 78, + 291, + 192 + ], + "lines": [ + { + "bbox": [ + 176, + 78, + 291, + 192 + ], + "spans": [ + { + "bbox": [ + 176, + 78, + 291, + 192 + ], + "type": "image", + "image_path": "2c7aae48cfcd35add5b9787e25e8286df7947cae899639cf622a7857fb5224d5.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 181, + 199, + 288, + 209 + ], + "lines": [ + { + "bbox": [ + 181, + 199, + 288, + 209 + ], + "spans": [ + { + "bbox": [ + 181, + 199, + 288, + 209 + ], + "type": "text", + "content": "(b) " + }, + { + "bbox": [ + 181, + 199, + 288, + 209 + ], + "type": "inline_equation", + "content": "w / o" + }, + { + "bbox": [ + 181, + 199, + 288, + 209 + ], + "type": "text", + "content": " memory and " + }, + { + "bbox": [ + 181, + 199, + 288, + 209 + ], + "type": "inline_equation", + "content": "w/" + }, + { + "bbox": [ + 181, + 199, + 288, + 209 + ], + "type": "text", + "content": " attention" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 300, + 78, + 415, + 192 + ], + "blocks": [ + { + "bbox": [ + 300, + 78, + 415, + 192 + ], + "lines": [ + { + "bbox": [ + 300, + 78, + 415, + 192 + ], + "spans": [ + { + "bbox": [ + 300, + 78, + 415, + 192 + ], + "type": "image", + "image_path": "b98afde71d03efafd8f3551aed53ec0ef612be966c2fc82c8707abc18c42c986.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 199, + 412, + 209 + ], + "lines": [ + { + "bbox": [ + 305, + 199, + 412, + 209 + ], + "spans": [ + { + "bbox": [ + 305, + 199, + 412, + 209 + ], + "type": "text", + "content": "(c) " + }, + { + "bbox": [ + 305, + 199, + 412, + 209 + ], + "type": "inline_equation", + "content": "w/" + }, + { + "bbox": [ + 305, + 199, + 412, + 209 + ], + "type": "text", + "content": " memory and " + }, + { + "bbox": [ + 305, + 199, + 412, + 209 + ], + "type": "inline_equation", + "content": "w/o" + }, + { + "bbox": [ + 305, + 199, + 412, + 209 + ], + "type": "text", + "content": " attention" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 213, + 546, + 257 + ], + "lines": [ + { + "bbox": [ + 46, + 213, + 546, + 257 + ], + "spans": [ + { + "bbox": [ + 46, + 213, + 546, + 257 + ], + "type": "text", + "content": "Figure 4. Visualization of Track Embedding " + }, + { + "bbox": [ + 46, + 213, + 546, + 257 + ], + "type": "inline_equation", + "content": "E_{tck}^{t}" + }, + { + "bbox": [ + 46, + 213, + 546, + 257 + ], + "type": "text", + "content": " (the first 50 frames in sequence dancetrack0063) from different structure designs by using t-Distributed Stochastic Neighbor Embedding (t-SNE). Track embeddings for different tracked targets (IDs) are marked in different colors and shapes. Our design 4(d) helps the model learn a more stable and distinguishable representation for the track embedding. Corresponding tracking performance is shown in Table 6." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 424, + 78, + 539, + 192 + ], + "blocks": [ + { + "bbox": [ + 424, + 78, + 539, + 192 + ], + "lines": [ + { + "bbox": [ + 424, + 78, + 539, + 192 + ], + "spans": [ + { + "bbox": [ + 424, + 78, + 539, + 192 + ], + "type": "image", + "image_path": "abc8835bc4f651d8b33671732b4adaac2cab12ea9a9aa987e80c6612f1a58049.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 421, + 199, + 544, + 209 + ], + "lines": [ + { + "bbox": [ + 421, + 199, + 544, + 209 + ], + "spans": [ + { + "bbox": [ + 421, + 199, + 544, + 209 + ], + "type": "text", + "content": "(d) " + }, + { + "bbox": [ + 421, + 199, + 544, + 209 + ], + "type": "inline_equation", + "content": "w/" + }, + { + "bbox": [ + 421, + 199, + 544, + 209 + ], + "type": "text", + "content": " memory and " + }, + { + "bbox": [ + 421, + 199, + 544, + 209 + ], + "type": "inline_equation", + "content": "w/" + }, + { + "bbox": [ + 421, + 199, + 544, + 209 + ], + "type": "text", + "content": " attention (ours)" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 277, + 286, + 301 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 277, + 286, + 301 + ], + "spans": [ + { + "bbox": [ + 46, + 277, + 286, + 301 + ], + "type": "text", + "content": "memory-attention layer by passing the temporal aggregation " + }, + { + "bbox": [ + 46, + 277, + 286, + 301 + ], + "type": "inline_equation", + "content": "\\hat{O}_{tck}^{t}" + }, + { + "bbox": [ + 46, + 277, + 286, + 301 + ], + "type": "text", + "content": " directly to an FFN network." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 301, + 287, + 373 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 301, + 287, + 373 + ], + "spans": [ + { + "bbox": [ + 46, + 301, + 287, + 373 + ], + "type": "text", + "content": "Our experimental results show that utilizing long-term memory produces a better association performance, with " + }, + { + "bbox": [ + 46, + 301, + 287, + 373 + ], + "type": "inline_equation", + "content": "+0.8\\%" + }, + { + "bbox": [ + 46, + 301, + 287, + 373 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 301, + 287, + 373 + ], + "type": "inline_equation", + "content": "+4.3\\%" + }, + { + "bbox": [ + 46, + 301, + 287, + 373 + ], + "type": "text", + "content": " AssA for w/o and w/ memory-attention layer. The injection of long-term memory significantly stabilizes and augments the identity information of each track embedding, as visualized in Figure 4(c) and 4(d)." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 374, + 287, + 517 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 374, + 287, + 517 + ], + "spans": [ + { + "bbox": [ + 46, + 374, + 287, + 517 + ], + "type": "text", + "content": "Memory Attention. In Table 6, we also ablate memory-attention layer. It shows that by using memory-attention layer, our MeMOTR achieves much better performance (63.9 vs. 62.5 HOTA), especially improving AssA by " + }, + { + "bbox": [ + 46, + 374, + 287, + 517 + ], + "type": "inline_equation", + "content": "2.1\\%" + }, + { + "bbox": [ + 46, + 374, + 287, + 517 + ], + "type": "text", + "content": ". This attention layer establishes interactions between different trajectories that help the track embedding learns discriminative features. However, without long-term memory " + }, + { + "bbox": [ + 46, + 374, + 287, + 517 + ], + "type": "inline_equation", + "content": "M_{tck}^{t}" + }, + { + "bbox": [ + 46, + 374, + 287, + 517 + ], + "type": "text", + "content": ", memory-attention layer produces worse performance " + }, + { + "bbox": [ + 46, + 374, + 287, + 517 + ], + "type": "inline_equation", + "content": "(-1.4\\%)" + }, + { + "bbox": [ + 46, + 374, + 287, + 517 + ], + "type": "text", + "content": " AssA and " + }, + { + "bbox": [ + 46, + 374, + 287, + 517 + ], + "type": "inline_equation", + "content": "-1.7\\%" + }, + { + "bbox": [ + 46, + 374, + 287, + 517 + ], + "type": "text", + "content": " IDF1. We explain that the track embedding without memory augmentation is unstable. Therefore, interacting with such unreliable information can be counterproductive, as visualized in Figure 4(b)." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 517, + 287, + 637 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 517, + 287, + 637 + ], + "spans": [ + { + "bbox": [ + 46, + 517, + 287, + 637 + ], + "type": "text", + "content": "Memory Update Rate. Here, we explored the impact of long-term memory update rate " + }, + { + "bbox": [ + 46, + 517, + 287, + 637 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 517, + 287, + 637 + ], + "type": "text", + "content": " on the tracking performance in Equation 1. As shown in Table 7, when progressively increasing the " + }, + { + "bbox": [ + 46, + 517, + 287, + 637 + ], + "type": "inline_equation", + "content": "\\lambda_{L}" + }, + { + "bbox": [ + 46, + 517, + 287, + 637 + ], + "type": "text", + "content": " from 0.005 to 0.04, our model achieves the highest HOTA score at " + }, + { + "bbox": [ + 46, + 517, + 287, + 637 + ], + "type": "inline_equation", + "content": "\\lambda = 0.01" + }, + { + "bbox": [ + 46, + 517, + 287, + 637 + ], + "type": "text", + "content": " while DetA score is decreasing slightly. We suggest the update rate " + }, + { + "bbox": [ + 46, + 517, + 287, + 637 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 46, + 517, + 287, + 637 + ], + "type": "text", + "content": " may be a hyperparameter that needs to be chosen according to different datasets. For example, scenarios with plenty of target non-rigid deformation may need a higher memory update rate to adapt to the rapidly changing features." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 47, + 647, + 124, + 658 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 647, + 124, + 658 + ], + "spans": [ + { + "bbox": [ + 47, + 647, + 124, + 658 + ], + "type": "text", + "content": "4.7. Limitations" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "type": "text", + "content": "Although our MeMOTR brings a significant improvement in association performance, detection performance is still a drawback, especially in crowded scenarios (like MOT17 [23]). During experiments, we observed that some" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 277, + 545, + 408 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 277, + 545, + 408 + ], + "spans": [ + { + "bbox": [ + 304, + 277, + 545, + 408 + ], + "type": "text", + "content": "times newborn objects are suppressed by tracked targets in the self-attention structure, which leads to reduced detection performance. Therefore, resolving this conflict is a crucial challenge for the joint tracking paradigm. This may help improve the detection capabilities, which can boost the overall tracking performance of the model, as studied in [45]. In addition, in pedestrian tracking, existing datasets are still limited in size and diversity. We suggest that training with other simulation datasets (like MOTSynth [11]) may alleviate the overfitting problem of our model and achieve better tracking performance." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 426, + 378, + 437 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 426, + 378, + 437 + ], + "spans": [ + { + "bbox": [ + 306, + 426, + 378, + 437 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 449, + 545, + 615 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 449, + 545, + 615 + ], + "spans": [ + { + "bbox": [ + 304, + 449, + 545, + 615 + ], + "type": "text", + "content": "We have proposed MeMOTR, an end-to-end long-term memory-augmented Transformer for multi-object tracking. Our method builds a stable long-term memory for each tracked object and exploits this memory to augment the representation of track embedding, thus improving its association performance. Furthermore, by leveraging a memory-attention layer, our model makes different targets more distinguishable. As a result, our approach achieves the state-of-the-art performance on MOT benchmarks, especially in scenes with irregular motion patterns. Extensive ablation experiments and visualizations demonstrate the effectiveness of our components. We hope that future work will pay more attention to the use of long-term temporal information for object tracking." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": "Acknowledgements. This work is supported by National Key R&D Program of China (No. 2022ZD0160900), National Natural Science Foundation of China (No. 62076119, No. 61921006), Fundamental Research Funds for the Central Universities (No. 020214380091, No. 020214380099), and Collaborative Innovation Center of Novel Software Technology and Industrialization. Besides, Ruopeng Gao would like to thank Muyan Yang for her social support." + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "9908" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 124 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 124 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 124 + ], + "type": "text", + "content": "[1] Philipp Bergmann, Tim Meinhardt, and Laura Leal-Taixe. Tracking without bells and whistles. In ICCV, pages 941-951. IEEE, 2019. 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 126, + 287, + 158 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 126, + 287, + 158 + ], + "spans": [ + { + "bbox": [ + 53, + 126, + 287, + 158 + ], + "type": "text", + "content": "[2] Keni Bernstein and Rainer Stiefelhagen. Evaluating multiple object tracking performance: The CLEAR MOT metrics. EURASIP J. Image Video Process., 2008, 2008. 5" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 160, + 287, + 192 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 160, + 287, + 192 + ], + "spans": [ + { + "bbox": [ + 53, + 160, + 287, + 192 + ], + "type": "text", + "content": "[3] Alex Bewley, ZongYuan Ge, Lionel Ott, Fabio Tozeto Ramos, and Ben Upcroft. Simple online and realtime tracking. In ICIP, pages 3464-3468. IEEE, 2016. 1, 2, 5, 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 194, + 287, + 237 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 194, + 287, + 237 + ], + "spans": [ + { + "bbox": [ + 53, + 194, + 287, + 237 + ], + "type": "text", + "content": "[4] Jiarui Cai, Mingze Xu, Wei Li, Yuanjun Xiong, Wei Xia, Zhuowen Tu, and Stefano Soatto. Memot: Multi-object tracking with memory. In CVPR, pages 8080-8090. IEEE, 2022. 2, 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 240, + 287, + 283 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 240, + 287, + 283 + ], + "spans": [ + { + "bbox": [ + 53, + 240, + 287, + 283 + ], + "type": "text", + "content": "[5] Jinkun Cao, Xinshuo Weng, Rawal Khirodkar, Jiangmiao Pang, and Kris Kitani. Observation-centric SORT: rethinking SORT for robust multi-object tracking. CoRR, abs/2203.14360, 2022. 1, 2, 5, 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 285, + 287, + 339 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 285, + 287, + 339 + ], + "spans": [ + { + "bbox": [ + 53, + 285, + 287, + 339 + ], + "type": "text", + "content": "[6] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In ECCV(1), volume 12346 of Lecture Notes in Computer Science, pages 213-229. Springer, 2020. 2, 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 342, + 287, + 385 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 342, + 287, + 385 + ], + "spans": [ + { + "bbox": [ + 53, + 342, + 287, + 385 + ], + "type": "text", + "content": "[7] Wongun Choi and Silvio Savarese. A unified framework for multi-target tracking and collective activity recognition. In ECCV (4), volume 7575 of Lecture Notes in Computer Science, pages 215-230. Springer, 2012. 1" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 387, + 287, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 387, + 287, + 430 + ], + "spans": [ + { + "bbox": [ + 53, + 387, + 287, + 430 + ], + "type": "text", + "content": "[8] Yutao Cui, Chenkai Zeng, Xiaoyu Zhao, Yichun Yang, Gangshan Wu, and Limin Wang. SportsMOT: A large multi-object tracking dataset in multiple sports scenes. In ICCV, 2023. 1" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 432, + 287, + 485 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 432, + 287, + 485 + ], + "spans": [ + { + "bbox": [ + 53, + 432, + 287, + 485 + ], + "type": "text", + "content": "[9] Patrick Dendorfer, Hamid Rezatofighi, Anton Milan, Javen Shi, Daniel Cremers, Ian D. Reid, Stefan Roth, Konrad Schindler, and Laura Leal-Taixe. MOT20: A benchmark for multi object tracking in crowded scenes. CoRR, abs/2003.09003, 2020. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 488, + 287, + 531 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 488, + 287, + 531 + ], + "spans": [ + { + "bbox": [ + 48, + 488, + 287, + 531 + ], + "type": "text", + "content": "[10] Patrick Dendorfer, Vladimir Yugay, Aljosa Osep, and Laura Leal-Taixe. Quo vadis: Is trajectory forecasting the key towards long-term multi-object tracking? In NeurIPS, 2022. 2, 6" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 533, + 287, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 533, + 287, + 588 + ], + "spans": [ + { + "bbox": [ + 48, + 533, + 287, + 588 + ], + "type": "text", + "content": "[11] Matteo Fabbri, Guillem Brasó, Gianluca Maugeri, Orcun Cetintas, Riccardo Gasparini, Aljosa Osep, Simone Calderara, Laura Leal-Taixe, and Rita Cucchiara. Motsynth: How can synthetic data help pedestrian detection and tracking? In ICCV, pages 10829-10839. IEEE, 2021. 8" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 590, + 287, + 622 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 590, + 287, + 622 + ], + "spans": [ + { + "bbox": [ + 48, + 590, + 287, + 622 + ], + "type": "text", + "content": "[12] Zheng Ge, Songtao Liu, Feng Wang, Zeming Li, and Jian Sun. YOLOX: exceeding YOLO series in 2021. CoRR, abs/2107.08430, 2021. 1, 2, 5, 6" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 624, + 287, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 624, + 287, + 678 + ], + "spans": [ + { + "bbox": [ + 48, + 624, + 287, + 678 + ], + "type": "text", + "content": "[13] Silvio Giancola, Mohieddine Amine, Tarek Dghaily, and Bernard Ghanem. Socernet: A scalable dataset for action spotting in soccer videos. In CVPR Workshops, pages 1711-1721. Computer Vision Foundation / IEEE Computer Society, 2018. 1" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "type": "text", + "content": "[14] Agrim Gupta, Justin Johnson, Li Fei-Fei, Silvio Savarese, and Alexandre Alahi. Social GAN: socially acceptable trajectories with generative adversarial networks. In CVPR," + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 31, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "text", + "content": "pages 2255-2264. Computer Vision Foundation / IEEE Computer Society, 2018. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 96, + 545, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 96, + 545, + 128 + ], + "spans": [ + { + "bbox": [ + 308, + 96, + 545, + 128 + ], + "type": "text", + "content": "[15] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778. IEEE Computer Society, 2016. 2, 3, 5" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 129, + 545, + 171 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 129, + 545, + 171 + ], + "spans": [ + { + "bbox": [ + 308, + 129, + 545, + 171 + ], + "type": "text", + "content": "[16] Weiming Hu, Tieniu Tan, Liang Wang, and Stephen J. Maybank. A survey on visual surveillance of object motion and behaviors. IEEE Trans. Syst. Man Cybern. Part C, 34(3):334-352, 2004. 1" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 173, + 545, + 204 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 173, + 545, + 204 + ], + "spans": [ + { + "bbox": [ + 308, + 173, + 545, + 204 + ], + "type": "text", + "content": "[17] Bruno Korbar and Andrew Zisserman. End-to-end tracking with a multi-query transformer. CoRR, abs/2210.14601, 2022. 2, 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 206, + 545, + 249 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 206, + 545, + 249 + ], + "spans": [ + { + "bbox": [ + 308, + 206, + 545, + 249 + ], + "type": "text", + "content": "[18] Siyuan Li, Martin Danelljan, Henghui Ding, Thomas E. Huang, and Fisher Yu. Tracking every thing in the wild. In ECCV (22), volume 13682 of Lecture Notes in Computer Science, pages 498-515. Springer, 2022. 6" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 251, + 545, + 304 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 251, + 545, + 304 + ], + "spans": [ + { + "bbox": [ + 308, + 251, + 545, + 304 + ], + "type": "text", + "content": "[19] Tsung-Yi Lin, Michael Maire, Serge J. Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólar, and C. Lawrence Zitnick. Microsoft COCO: common objects in context. In ECCV (5), volume 8693 of Lecture Notes in Computer Science, pages 740-755. Springer, 2014. 5" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 306, + 545, + 347 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 306, + 545, + 347 + ], + "spans": [ + { + "bbox": [ + 308, + 306, + 545, + 347 + ], + "type": "text", + "content": "[20] Shilong Liu, Feng Li, Hao Zhang, Xiao Yang, Xianbiao Qi, Hang Su, Jun Zhu, and Lei Zhang. DAB-DETR: dynamic anchor boxes are better queries for DETR. In ICLR. OpenReview.net, 2022. 3, 5" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 350, + 545, + 402 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 350, + 545, + 402 + ], + "spans": [ + { + "bbox": [ + 308, + 350, + 545, + 402 + ], + "type": "text", + "content": "[21] Jonathon Luiten, Aljosa Osep, Patrick Dendorfer, Philip H. S. Torr, Andreas Geiger, Laura Leal-Taixe, and Bastian Leibe. HOTA: A higher order metric for evaluating multi-object tracking. Int. J. Comput. Vis., 129(2):548-578, 2021. 5" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 405, + 545, + 447 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 405, + 545, + 447 + ], + "spans": [ + { + "bbox": [ + 308, + 405, + 545, + 447 + ], + "type": "text", + "content": "[22] Tim Meinhardt, Alexander Kirillov, Laura Leal-Taixe, and Christoph Feichtenhofer. Trackformer: Multi-object tracking with transformers. In CVPR, pages 8834-8844. IEEE, 2022. 1, 2, 3, 6" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 449, + 545, + 491 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 449, + 545, + 491 + ], + "spans": [ + { + "bbox": [ + 308, + 449, + 545, + 491 + ], + "type": "text", + "content": "[23] Anton Milan, Laura Leal-Taixe, Ian D. Reid, Stefan Roth, and Konrad Schindler. MOT16: A benchmark for multi-object tracking. CoRR, abs/1603.00831, 2016. 1, 2, 4, 5, 6, 7, 8" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 494, + 545, + 536 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 494, + 545, + 536 + ], + "spans": [ + { + "bbox": [ + 308, + 494, + 545, + 536 + ], + "type": "text", + "content": "[24] Jiangmiao Pang, Linlu Qiu, Xia Li, Haofeng Chen, Qi Li, Trevor Darrell, and Fisher Yu. Quasi-dense similarity learning for multiple object tracking. In CVPR, pages 164-173. Computer Vision Foundation / IEEE, 2021. 5, 6" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 537, + 545, + 592 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 537, + 545, + 592 + ], + "spans": [ + { + "bbox": [ + 308, + 537, + 545, + 592 + ], + "type": "text", + "content": "[25] Ergys Ristani, Francesco Solera, Roger S. Zou, Rita Cucchiara, and Carlo Tomasi. Performance measures and a data set for multi-target, multi-camera tracking. In ECCV Workshops (2), volume 9914 of Lecture Notes in Computer Science, pages 17-35, 2016. 5" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 593, + 545, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 593, + 545, + 635 + ], + "spans": [ + { + "bbox": [ + 308, + 593, + 545, + 635 + ], + "type": "text", + "content": "[26] Ergys Ristani and Carlo Tomasi. Features for multi-target multi-camera tracking and re-identification. In CVPR, pages 6036–6046. Computer Vision Foundation / IEEE Computer Society, 2018. 1" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 636, + 545, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 636, + 545, + 678 + ], + "spans": [ + { + "bbox": [ + 308, + 636, + 545, + 678 + ], + "type": "text", + "content": "[27] Shuai Shao, Zijian Zhao, Boxun Li, Tete Xiao, Gang Yu, Xiangyu Zhang, and Jian Sun. Crowdhuman: A benchmark for detecting human in a crowd. CoRR, abs/1805.00123, 2018. 5" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 308, + 681, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 681, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 681, + 545, + 713 + ], + "type": "text", + "content": "[28] Chris Stauffer and W. Eric L. Grimson. Adaptive background mixture models for real-time tracking. In CVPR, pages 2246-2252. IEEE Computer Society, 1999. 1, 3" + } + ] + } + ], + "index": 30 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "9909" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 715 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 117 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 117 + ], + "type": "text", + "content": "[29] Peize Sun, Jinkun Cao, Yi Jiang, Zehuan Yuan, Song Bai, Kris Kitani, and Ping Luo. Dancetrack: Multi-object tracking in uniform appearance and diverse motion. In CVPR, pages 20961-20970. IEEE, 2022. 1, 2, 4, 5, 7" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 118, + 287, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 118, + 287, + 162 + ], + "spans": [ + { + "bbox": [ + 49, + 118, + 287, + 162 + ], + "type": "text", + "content": "[30] Peize Sun, Yi Jiang, Rufeng Zhang, Enze Xie, Jinkun Cao, Xinting Hu, Tao Kong, Zehuan Yuan, Changhu Wang, and Ping Luo. Transtrack: Multiple-object tracking with transformer. CoRR, abs/2012.15460, 2020. 2, 5, 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 163, + 288, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 163, + 288, + 206 + ], + "spans": [ + { + "bbox": [ + 48, + 163, + 288, + 206 + ], + "type": "text", + "content": "[31] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N. Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In NIPS, pages 5998-6008, 2017. 3, 4, 6" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 208, + 288, + 252 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 208, + 288, + 252 + ], + "spans": [ + { + "bbox": [ + 48, + 208, + 288, + 252 + ], + "type": "text", + "content": "[32] Zhongdao Wang, Liang Zheng, Yixuan Liu, Yali Li, and Shengjin Wang. Towards real-time multi-object tracking. In ECCV (11), volume 12356 of Lecture Notes in Computer Science, pages 107-122. Springer, 2020. 1, 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 253, + 288, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 253, + 288, + 274 + ], + "spans": [ + { + "bbox": [ + 48, + 253, + 288, + 274 + ], + "type": "text", + "content": "[33] Greg Welch, Gary Bishop, et al. An introduction to the kalman filter. 1995. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 276, + 288, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 276, + 288, + 308 + ], + "spans": [ + { + "bbox": [ + 48, + 276, + 288, + 308 + ], + "type": "text", + "content": "[34] Nicolai Wojke, Alex Bewley, and Dietrich Paulus. Simple online and realtime tracking with a deep association metric. In ICIP, pages 3645-3649. IEEE, 2017. 2, 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 310, + 288, + 354 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 310, + 288, + 354 + ], + "spans": [ + { + "bbox": [ + 48, + 310, + 288, + 354 + ], + "type": "text", + "content": "[35] Sanghyun Woo, Kwanyong Park, Seoul Wug Oh, In So Kweon, and Joon-Young Lee. Tracking by associating clips. In ECCV (25), volume 13685 of Lecture Notes in Computer Science, pages 129–145. Springer, 2022. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 355, + 287, + 399 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 355, + 287, + 399 + ], + "spans": [ + { + "bbox": [ + 48, + 355, + 287, + 399 + ], + "type": "text", + "content": "[36] Jialian Wu, Jiale Cao, Liangchen Song, Yu Wang, Ming Yang, and Junsong Yuan. Track to detect and segment: An online multi-object tracker. In CVPR, pages 12352-12361. Computer Vision Foundation / IEEE, 2021. 5, 6" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 399, + 288, + 443 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 399, + 288, + 443 + ], + "spans": [ + { + "bbox": [ + 48, + 399, + 288, + 443 + ], + "type": "text", + "content": "[37] Yihong Xu, Yutong Ban, Guillaume Delorme, Chuang Gan, Daniela Rus, and Xavier Alameda-Pineda. Transcenter: Transformers with dense queries for multiple-object tracking. CoRR, abs/2103.15145, 2021. 6" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 445, + 288, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 445, + 288, + 498 + ], + "spans": [ + { + "bbox": [ + 48, + 445, + 288, + 498 + ], + "type": "text", + "content": "[38] Bin Yan, Yi Jiang, Peize Sun, Dong Wang, Zehuan Yuan, Ping Luo, and Huchuan Lu. Towards grand unification of object tracking. In ECCV (21), volume 13681 of Lecture Notes in Computer Science, pages 733-751. Springer, 2022. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 500, + 288, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 500, + 288, + 533 + ], + "spans": [ + { + "bbox": [ + 48, + 500, + 288, + 533 + ], + "type": "text", + "content": "[39] Feng Yan, Zhiheng Li, Weixin Luo, Zequn jie, Fan Liang, Xiaolin Wei, and Lin Ma. Multiple object tracking challenge technical report for team mt_iot, 2022. 5" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 535, + 288, + 578 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 535, + 288, + 578 + ], + "spans": [ + { + "bbox": [ + 48, + 535, + 288, + 578 + ], + "type": "text", + "content": "[40] Fan Yang, Shigeyuki Odashima, Shoichi Masui, and Shan Jiang. Hard to track objects with irregular motions and similar appearances? make it easier by buffering the matching space. In WACV, pages 4788-4797. IEEE, 2023. 1, 5, 6" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 579, + 288, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 579, + 288, + 634 + ], + "spans": [ + { + "bbox": [ + 48, + 579, + 288, + 634 + ], + "type": "text", + "content": "[41] Fisher Yu, Haofeng Chen, Xin Wang, Wenqi Xian, Yingying Chen, Fangchen Liu, Vashisht Madhavan, and Trevor Darrell. BDD100K: A diverse driving dataset for heterogeneous multitask learning. In CVPR, pages 2633-2642. Computer Vision Foundation / IEEE, 2020. 2, 4, 5, 6" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 635, + 288, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 635, + 288, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 635, + 288, + 689 + ], + "type": "text", + "content": "[42] Fangao Zeng, Bin Dong, Yuang Zhang, Tiancai Wang, Xi-angyu Zhang, and Yichen Wei. MOTR: end-to-end multiple-object tracking with transformer. In ECCV (27), volume 13687 of Lecture Notes in Computer Science, pages 659–675. Springer, 2022. 1, 2, 3, 5, 6" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 691, + 288, + 715 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 288, + 715 + ], + "type": "text", + "content": "[43] Yifu Zhang, Peize Sun, Yi Jiang, Dongdong Yu, Fucheng Weng, Zehuan Yuan, Ping Luo, Wenyu Liu, and Xinggang" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 307 + ], + "type": "list", + "angle": 0, + "index": 22, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "type": "text", + "content": "Wang. Bytetrack: Multi-object tracking by associating every detection box. In ECCV (22), volume 13682 of Lecture Notes in Computer Science, pages 1-21. Springer, 2022. 1, 2, 5, 6" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "type": "text", + "content": "[44] Yifu Zhang, Chunyu Wang, Xinggang Wang, Wenjun Zeng, and Wenyu Liu. Fairmot: On the fairness of detection and re-identification in multiple object tracking. Int. J. Comput. Vis., 129(11):3069-3087, 2021. 2, 5, 6" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 152, + 545, + 185 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 185 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 185 + ], + "type": "text", + "content": "[45] Yang Zhang, Tiancai Wang, and Xiangyu Zhang. Motrv2: Bootstrapping end-to-end multi-object tracking by pretrained object detectors, 2022. 5, 6, 8" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 186, + 545, + 230 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 186, + 545, + 230 + ], + "spans": [ + { + "bbox": [ + 307, + 186, + 545, + 230 + ], + "type": "text", + "content": "[46] Xingyi Zhou, Vladlen Koltun, and Philipp Krahenbuhl. Tracking objects as points. In ECCV (4), volume 12349 of Lecture Notes in Computer Science, pages 474-490. Springer, 2020. 5, 6" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 231, + 545, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 231, + 545, + 262 + ], + "spans": [ + { + "bbox": [ + 307, + 231, + 545, + 262 + ], + "type": "text", + "content": "[47] Xingyi Zhou, Tianwei Yin, Vladlen Koltun, and Philipp Krahenbihl. Global tracking transformers. In CVPR, pages 8761-8770. IEEE, 2022. 2, 5, 6" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 264, + 545, + 307 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 264, + 545, + 307 + ], + "spans": [ + { + "bbox": [ + 308, + 264, + 545, + 307 + ], + "type": "text", + "content": "[48] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable DETR: deformable transformers for end-to-end object detection. In ICLR. OpenReview.net, 2021. 5" + } + ] + } + ], + "index": 21 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 316, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 316, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 316, + 757 + ], + "type": "text", + "content": "9910" + } + ] + } + ], + "index": 23 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/422d1f87-df33-4f64-91c1-e11c03538001_content_list.json b/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/422d1f87-df33-4f64-91c1-e11c03538001_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..c4cab121910c53035344026bf85f9508d9d10a37 --- /dev/null +++ b/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/422d1f87-df33-4f64-91c1-e11c03538001_content_list.json @@ -0,0 +1,1703 @@ +[ + { + "type": "text", + "text": "MeViS: A Large-scale Benchmark for Video Segmentation with Motion Expressions", + "text_level": 1, + "bbox": [ + 189, + 130, + 779, + 175 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Henghui Ding† Chang Liu‡ Shuting He‡ Xudong Jiang‡ Chen Change Loy† \n†S-Lab, Nanyang Technological University ‡School of EEE, Nanyang Technological University https://henghuiding.github.io/MeViS", + "bbox": [ + 99, + 202, + 869, + 257 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/8d09679b058034e7c0e0a113e87343a66f0de249e878c1c8c4237876547b1a96.jpg", + "image_caption": [ + "First Frame" + ], + "image_footnote": [], + "bbox": [ + 81, + 301, + 196, + 352 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/798617559adaeed9e11156a0bc1d0ebf23bd7e55266266e22cb679d0b143d42b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 199, + 301, + 313, + 352 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/35d7ab30b081707096a3a6658f0c248ff2ed05b8318a05b2e52787f335f5a912.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 315, + 301, + 428, + 352 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/b18065ea7702eba94aac72070e93798bf12f1f5219e01f24b7f5da406e5433fc.jpg", + "image_caption": [ + "\"The bird flying away\"" + ], + "image_footnote": [], + "bbox": [ + 428, + 301, + 542, + 352 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/0fbd6692630e9ffab0caf500676060ee2c357d29eef3877c7a3774ddd4a03093.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 542, + 301, + 656, + 352 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/bdaca24e959789161093efa2a452b82b80687dc27f93c3f395af9f3de26ea84a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 656, + 301, + 771, + 352 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/18af1536fd1197e4b52b4017e26d30db10baea00904a186dbe4211b87fcaa0bd.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 772, + 301, + 887, + 352 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/ab1c916b16a97d206c32ad50bc1e06da9a514bb6a18ac34916bc2fbf15b4957e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 81, + 368, + 194, + 419 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/1eea54912ba18f35c12f6d15a6e6ef3fb92598745b24aa2d5b35366755ff7835.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 199, + 368, + 313, + 419 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/0d58b3f0c15eb2b7cdf6689717b3a3e4cb42356f1be0ae5b7811b877e8bff5ed.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 315, + 368, + 428, + 417 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/b5750f9762dae3372c90c5de3da36ceb49a84476d23f92aa36162a2b08574380.jpg", + "image_caption": [ + "\"The cat playing with the teaser\"" + ], + "image_footnote": [], + "bbox": [ + 429, + 368, + 542, + 417 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/fd35b3a0614045da8409fcdf658fa00d4b439f766ad766e18685e605af5ba7e2.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 542, + 368, + 656, + 417 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/e6610a5240b6600d42f4364297f9dd04d96ed38daa5b85868280e1e7dbaff32e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 656, + 368, + 771, + 417 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/f63f3863f74d89bf1de6bec7786f03f8f5dfb931139a97bb863850329b380dc1.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 772, + 368, + 887, + 419 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/e1729cbb70ea858f0ba174a0955f1be7039a0047a1bb623457329507ac3938e3.jpg", + "image_caption": [ + "Figure 1. Examples of video clips from Motion expressions Video Segmentation (MeViS) are provided to illustrate the dataset's nature and complexity. The expressions in MeViS primarily focus on motion attributes and the referred target object cannot be identified by examining a single frame solely. For instance, the first example features three parrots with similar appearances, and the target object is identified as \"The bird flying away\". This object can only be recognized by capturing its motion throughout the video." + ], + "image_footnote": [], + "bbox": [ + 80, + 435, + 196, + 484 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/235574c321e7fdaccfb49d505bf5ccf7c6e260d854e6bf4561ffa0523b3c78e6.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 200, + 435, + 313, + 484 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/89dca7143cd62cf0546ce0c52c067976c6dc2542643185f6e4405bd1c853694d.jpg", + "image_caption": [ + "\"Bears that walk forwards from left to right then walk back\"" + ], + "image_footnote": [], + "bbox": [ + 315, + 435, + 428, + 484 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/3b0a810d47432bb562ae4ddff754a58d9270fc2e7989f7d1c60a9d1f00a96d65.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 428, + 435, + 542, + 484 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/7655cd3a6691a59c389e1144b3923f33d7325309fce54e86429e38c71e75c9da.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 542, + 435, + 656, + 484 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/b0033eed38d5dd73f94dc949147ddaedd7ab77de00c1cfda72a55a1250631db6.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 656, + 435, + 771, + 484 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/73562a20892778198fdd2e2b292d0abe3973ccb818613ea00d76faeb0c43eeeb.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 772, + 435, + 887, + 484 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 565, + 313, + 580 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "This paper strives for motion expressions guided video segmentation, which focuses on segmenting objects in video content based on a sentence describing the motion of the objects. Existing referring video object datasets typically focus on salient objects and use language expressions that contain excessive static attributes that could potentially enable the target object to be identified in a single frame. These datasets downplay the importance of motion in video content for language-guided video object segmentation. To investigate the feasibility of using motion expressions to ground and segment objects in videos, we propose a large-scale dataset called MeViS, which contains numerous motion expressions to indicate target objects in complex environments. We benchmarked 5 existing referring video object segmentation (RVOS) methods and conducted a comprehensive comparison on the MeViS dataset. The results show that current RVOS methods cannot effectively address motion expression-guided video segmentation. We further analyze the challenges and propose a baseline", + "bbox": [ + 73, + 590, + 470, + 878 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "approach for the proposed MeViS dataset. The goal of our benchmark is to provide a platform that enables the development of effective language-guided video segmentation algorithms that leverage motion expressions as a primary cue for object segmentation in complex video scenes. The proposed MeViS dataset has been released at https://henghuiding.github.io/MeViS.", + "bbox": [ + 500, + 566, + 893, + 672 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 501, + 707, + 632, + 722 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Language-guided video segmentation is an emerging field that involves segmenting and tracking target objects using natural language expressions. This field has traditionally been a sub-branch of semi-supervised video object segmentation, where referring expressions are used to describe the target object. Existing referring video object datasets, such as [13,21,44], commonly feature videos with isolated and salient objects that have obvious static features. The corresponding expressions often contain static attributes such as object color, which can be observed in a single frame. As a result, motion properties of videos are often", + "bbox": [ + 496, + 734, + 893, + 900 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "henghui.ding@gmail.com, ccloy@ntu.edu.sg", + "bbox": [ + 99, + 887, + 357, + 900 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "2694", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "given less emphasis, and referring image segmentation methods can be used for referring video segmentation, achieving good results [1, 10, 21, 31].", + "bbox": [ + 78, + 90, + 465, + 136 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this paper, we wish to highlight the significance of temporal motion properties of videos and explore the potential of using motion expressions to segment objects in videos. To this end, we propose a new large-scale dataset called Motion expressions Video Segmentation (MeViS) to aid our investigation. The MeViS dataset comprises 2,006 videos with a total of 8,171 objects, and 28,570 motion expressions are provided to refer to these objects.", + "bbox": [ + 78, + 138, + 465, + 258 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We take several steps to ensure that the MeViS dataset places emphasis on the temporal motions of videos. First, we carefully select video content that contains multiple objects that coexist with motion and exclude videos with isolated objects that can be easily described by static attributes. Second, we prioritize language expressions that do not contain static clues, such as category names or object colors, in cases where target objects can be unambiguously described by motion words alone. This is distinct from previous datasets, such as [13, 21, 44], which include obvious static clues in their expressions. Additionally, MeViS differentiates itself from referring image segmentation datasets, such as [20, 36, 53, 62], which do not account for the temporal properties of video content. Moreover, unlike existing referring video object segmentation datasets that focus on single-target expressions, where one expression refers to only one target object, MeViS expands this task to include multi-object expressions that refer to multiple target objects. This feature enables expressions to refer to an unlimited number of target objects, making the proposed MeViS more challenging and reflective of real-world scenarios.", + "bbox": [ + 78, + 261, + 465, + 578 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The proposed MeViS dataset poses notable challenges in capturing and understanding motions in both video and language. The language expressions may describe motion that spans a random number of frames, requiring the capture of fleeting movements and long-term actions that occur throughout the entire video. This poses significant challenges for both understanding motion in the video content and in the accompanying language expressions. Capturing fleeting movements requires attention on each individual frame, while understanding long and complex movements that span across many frames demands temporal context across the entire video. With the proposed dataset, we benchmark 5 existing referring video object segmentation (RVOS) methods [2, 10, 11, 44, 55] and conduct a comprehensive comparison. The experimental results demonstrate that MeViS presents more challenges than existing datasets, and current RVOS methods are unable to effectively address motion expression-guided video segmentation.", + "bbox": [ + 78, + 580, + 465, + 852 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In addition to proposing the MeViS dataset, we present a baseline approach, named Language-guided Motion Perception and Matching (LMPM), to address the challenges", + "bbox": [ + 78, + 854, + 465, + 898 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "posed by the dataset. Our approach generates language-conditional queries to detect potential target objects in the video and represents them using object embeddings, which are more robust and computationally efficient than object feature maps [15]. We then perform Motion Perception on the object embeddings to capture the temporal context and obtain a global view of the video, enabling the model to understand both fleeting and long-term motions. Next, we use a Transformer decoder to decode language-related information from the motion-aggregated object embeddings and predict object trajectories. Finally, we perform similarity matching between the language features and the predicted object trajectories to identify the target object(s).", + "bbox": [ + 503, + 90, + 888, + 286 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Our contributions provide a foundation for developing more advanced language-guided video segmentation algorithms that leverage motion expressions as a primary cue for object segmentation and identification in complex video scenes. In particular, we propose a new language-guided video segmentation dataset, MeViS, and conduct comprehensive evaluations of state-of-the-art referring video object segmentation methods on the MeViS dataset, providing a reference for future works. We also develop a simple baseline approach, LMPM, which points to potential solutions to some of the challenges and future research directions.", + "bbox": [ + 503, + 287, + 888, + 452 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 503, + 467, + 638, + 483 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Referring Image Segmentation. Referring image segmentation [5, 9, 10, 27, 28], also known as referring expression segmentation, involves grounding the target object in images based on natural language expressions that describe its properties and generating a corresponding segmentation mask. This task requires both language and image understanding and is one of the most fundamental yet challenging tasks in computer vision. Referring image segmentation was first introduced by Hu et al. [16] in 2016 and has received considerable attention since then. In the preTransformer era, mainstream methods typically employed Fully Convolutional Networks (FCN) [6, 7, 34] and Recurrent Neural Networks (RNN) to extract image features and language features, respectively, and then fused the multimodal features via some specially designed modules [12, 23, 30, 37]. For example, Liu et al. [30] introduced a Recurrent Multimodal Interaction (RMI) module to recurrently fuse the feature of each word into the image features. Li et al. [23] proposed a Recurrent Refinement Network (RRN) that progressively refines the segmentation mask based on pyramid features in FCN.", + "bbox": [ + 503, + 492, + 888, + 808 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In addition to one-stage methods that fuse multi-modal features and conduct segmentation, some methods decouple referring image segmentation into instance segmentation and language-object matching [19, 29, 61]. For instance, Yu et al. use the off-the-shelf instance segmentation model Mask R-CNN [14] to detect all instances first and then", + "bbox": [ + 503, + 810, + 888, + 898 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "2695", + "bbox": [ + 483, + 946, + 513, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "select the one that best matches the language as output. A holistic understanding of language and vision information is crucial for referring image segmentation, and many works have explored this direction [18, 58, 60]. For instance, Ye et al. introduce a Cross-Modal Self-Attention (CMSA) model [60] to select the most meaningful words in the expression and pixels in the image to achieve better contextual understanding. Recently, the success of Transformer [47] in vision tasks has inspired many studies in referring image segmentation. Ding et al. [9, 10] first introduced Transformer into referring segmentation and proposed a Vision-Language Transformer (VLT). Following Ding et al. [9, 10], more Transformer-based methods have been proposed [22, 52, 59]. For example, Wang et al. [52] employ the Vision-Language Decoder to deal with visual and text tokens extracted by CLIP [43]. Yang et al. [59] focus on multi-modal feature fusion and propose a Language-Aware Vision Transformer (LAVT).", + "bbox": [ + 76, + 90, + 472, + 361 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Referring Video Segmentation. Referring video object segmentation is an emerging area [3, 17, 31, 38, 39, 45, 46, 49, 50, 54, 57, 63] that aims to segment the target object indicated by a given expression across the entire video clip. It was first introduced in 2018 by A2D [13] and DAVIS17-RVOS [21], where A2D [13] seeks to segment actors according to descriptions of their actions in video content, and DAVIS17-RVOS [21] replaces masks with language as the reference for the target object in video object segmentation. Later, Seo et al. [44] built the Refer-YouTube-VOS based on the YouTube-VOS-2019 dataset [56]. These datasets typically provide an expression for a single object, and the expression usually describes the static attributes of the target object, such as its color and shape.", + "bbox": [ + 76, + 363, + 472, + 574 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Existing methods typically treat referring video segmentation as a form of semi-supervised video object segmentation [41] by replacing mask reference with language reference. For instance, Khoreva et al. [21] employ the referring image segmentation method MAttNet [61] to achieve frame-level segmentation and then perform post-processing for temporal consistency. URVOS [44] employs cross-modal attention to perform per-frame segmentation and propagate the mask across clips with a memory attention module. RefVOS [1] independently segments each frame based on the fused features of language and image/frame, without utilizing temporal information. Liang et al. [26] introduces a top-down approach that first detects all object tracklets and then selects the target object by matching between language and tracklet features. Most recently, ReferFormer [55] and MTTR [2] employ Transformer [47] to address referring video object segmentation.", + "bbox": [ + 76, + 575, + 472, + 833 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. MeViS Dataset", + "text_level": 1, + "bbox": [ + 76, + 845, + 228, + 861 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this section, we introduce the newly built large-scale dataset MeViS by first presenting the video collection and", + "bbox": [ + 76, + 869, + 470, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "annotation process in Section 3.1 and then providing the dataset statistics and analysis in Section 3.2.", + "bbox": [ + 498, + 90, + 890, + 122 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Motion Expression Annotation", + "text_level": 1, + "bbox": [ + 500, + 128, + 772, + 145 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Video Collection. We gather and choose videos from publicly available video segmentation datasets with high-quality mask annotations [8,42,48,51], and select the ones that meet our criteria for motion and object complexity. Our selection process involves the following rules:", + "bbox": [ + 498, + 157, + 893, + 234 + ], + "page_idx": 2 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "R1. We only include videos that have multiple objects within the frame in MeViS; videos with only one or two salient objects are not considered. We specifically look for videos that depict many objects with similar appearances, such as the first example video in Figure 1 which shows three yellow parrots.", + "R2. We select videos that contain objects that demonstrate substantial motion and movement. Videos depicting objects that have little or no motion are excluded." + ], + "bbox": [ + 501, + 237, + 893, + 375 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "After reviewing over 4,000 potential candidates, we carefully selected the most appropriate and suitable videos that meet our rigorous standards for both visual and linguistic content. Ultimately, by prioritizing quality over quantity, we chose 2,006 videos to create a benchmark that is diverse and representative of a wide range of real-world video scenarios. The basic language annotation methodology and procedure for MeViS follow the ReferIt [20], which is an interactive game-like approach that involves two players taking turns to annotate and validate. The following section will introduce the process of language expression annotation and validation in more detail.", + "bbox": [ + 498, + 375, + 893, + 554 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Language Expression Annotation. We developed a web-based annotation system for annotating language expressions. The system randomly selects a video from the MeViS dataset and displays all object masks of the selected video on the web system. The annotator needs to choose one or several objects from the video and write the corresponding referring expression according to the guidelines for annotating language expressions. To ensure that the language expressions in our dataset align with our focus on motion-based video segmentation, we established several guidelines for annotating the language expressions:", + "bbox": [ + 498, + 561, + 893, + 729 + ], + "page_idx": 2 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "A1. Target objects must exhibit significant motion. Objects that remain stationary or only demonstrate minimal motion should be disregarded.", + "A2. If an object can be unambiguously described by its motion or action, static attributes such as color should not be included in the expression.", + "A3. If multiple objects cannot be differentiated based solely on their motion or action, they can be described together if their motion or action can unambiguously identify them, such as \"The two lions fighting and running amidst a group of lions.\"" + ], + "bbox": [ + 500, + 734, + 893, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "2696", + "bbox": [ + 482, + 945, + 516, + 955 + ], + "page_idx": 2 + }, + { + "type": "table", + "img_path": "images/8e9cd45715314365c8256113156da14e3cb84f0effa6a859418adad7c380e805.jpg", + "table_caption": [ + "Table 1. Statistics of representative language-guided video segmentation datasets. The newly built MeViS has the largest number of objects and language expressions. More importantly, MeViS focuses on segmenting objects in the videos indicated by motion expressions. The MeViS enables the investigation of the feasibility of using motion expressions for object segmentation and grounding in videos." + ], + "table_footnote": [], + "table_body": "
DatasetYearPub.VideoObjectExpressionMaskObject/ VideoObject/ ExperisionTarget
A2D Sentence [13]2018CVPR3,7824,8256,65658k1.281Actor
J-HMDB Sentence [13]2018CVPR92892892831.8k11Actor
DAVIS16-RVOS [21]2018ACCV50501003.4k1n/aObject
DAVIS17-RVOS [21]2018ACCV902051,54413.5k2.271Object
Refer-Youtube-VOS [44]2020ECCV3,9787,45115,009131k1.861Object
MeViS (ours)2023ICCV2,0068,17128,570443k4.281.59Object(s)
", + "bbox": [ + 78, + 132, + 888, + 266 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "A4. If it is not possible to differentiate single or multiple objects based solely on their motion or action, limited static attributes can be included in the expression.", + "bbox": [ + 76, + 277, + 470, + 324 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Language Expression Validation. Upon receiving annotated \"video-object-expression\" samples from the annotators, the validation process begins by displaying the video and expression and prompting the validator to select and submit the objects referred to in the expression. The validator must find the targets independently and submit their selection. The system then compares the targets chosen by the validator with the annotations submitted by the annotator. A sample is considered valid if the validator and annotator independently selected the same target object(s) using the same expression. If the targets selected by the validator do not match the annotation submitted by the annotator, the sample will be forwarded to another validator for a second opinion. If the second validator also fails to identify the correct targets, the sample will be considered invalid and excluded from the dataset. Validator have the authority to reject samples that are deemed inappropriate or fall short of quality standards. Moreover, we stress the importance of the following validation criterion:", + "bbox": [ + 76, + 327, + 472, + 616 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "V1. The corresponding sentence will be removed from the dataset when the target object described by a sentence can be identified through a single frame without the need for motion information.", + "bbox": [ + 76, + 619, + 468, + 679 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "By establishing these validation criteria, we aim to ensure that the language sentences in our dataset accurately express motion and are of high quality, while also increasing the level of difficulty in the language-guided video segmentation task, thereby enabling a more robust evaluation of the performance of different models and methods.", + "bbox": [ + 76, + 685, + 468, + 776 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Dataset Analysis and Statistics", + "text_level": 1, + "bbox": [ + 76, + 786, + 346, + 801 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In Table 1, we present a statistical analysis of the newly proposed MeViS dataset, using 5 previous referring video object segmentation datasets as references, including A2D Sentence [13], J-HMDB Sentence [13], DAVIS16-RVOS [21], DAVIS17-RVOS [21], and Refer-Youtu-VOS [44]. As shown in Table 1, MeViS contains 2,006", + "bbox": [ + 76, + 809, + 470, + 900 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/91e79fe0ba098408afe6c3ce645eb1c40f1cb0de82c58f7f0f5de053e295826e.jpg", + "image_caption": [ + "(a). Durations of videos" + ], + "image_footnote": [], + "bbox": [ + 498, + 280, + 689, + 388 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/3bcf24c16111896ff871da85d13aa868af05898d64d0d73c95b5eef6a69e266e.jpg", + "image_caption": [ + "(b). Durations of objects", + "Figure 2. The duration of videos and objects of MeViS and Refer-Youtu-VOS [44], in seconds. The vertical lines and values in the legends represent the mean duration across the two datasets. The duration of both videos and objects in MeViS is significantly longer than Refer-Youtu-VOS." + ], + "image_footnote": [], + "bbox": [ + 696, + 282, + 885, + 388 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "videos and 8,171 objects. Compared to Refer-Youtu-VOS [44], which is based on the existing VOS dataset [56], MeViS has more objects (8,171 vs. 7,451), more expressions (28,570 vs. 15,009), and more annotation masks (443k vs. 131k). In the following, we discuss how the proposed dataset MeViS intentionally increases the complexities of language-guided video segmentation by considering the challenges of both linguistic and visual modalities.", + "bbox": [ + 496, + 489, + 892, + 611 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "- Video Content. As shown in Table 1, MeViS has an average of 4.28 objects per video, which is higher than previous datasets. Furthermore, as depicted in Figure 2, MeViS contains longer videos, with an average duration of 13.16 seconds, which is significantly longer than the Refer-Youtu-VOS dataset. These intentional design choices make MeViS more complex and challenging for language-guided video segmentation. This is in contrast to existing datasets such as A2D Sentence [13] and $\\mathrm{DAVIS}_{16}$ -RVOS [21], where only one or two salient objects per category are present, and the model can choose the most prominent object as the target or identify the target object based on the category name. For example, in Figure 3(b), there is only one person in the foreground, and the model can simply identify the target by the term \"a person\" while ignoring \"skateboarding\". The proposed MeViS dataset addresses this limitation by selecting videos with more objects that have diverse and dynamic motions. Moreover, MeViS features many videos with objects of the same", + "bbox": [ + 496, + 613, + 893, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "2697", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/0a1a18c9b085aeeee3868d49011958feb59058ac745b980f1d4914ba89b5a405.jpg", + "image_caption": [ + "(a). \"Giraffes turning around\"" + ], + "image_footnote": [], + "bbox": [ + 80, + 89, + 176, + 143 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/348d7f1eef02cebc8db282378e3a12159249290159050ee553109d1016fa7148.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 178, + 89, + 271, + 133 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/b6f6203cc699a86e138e2fe71378d0dde537384ce1d35e5b977d5202600c9913.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 274, + 89, + 369, + 133 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/ca17754a7f92310e0e97932cbabd6b1e9f8d7132d7082bd3214b0dff0f9b8425.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 370, + 90, + 465, + 133 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/261bd9855e5d96bf79a1eb6c252cc4d0ae0c69a6cd6b3fb5b2344b1629eabeeb.jpg", + "image_caption": [ + "(b). \"A person skating.\"" + ], + "image_footnote": [], + "bbox": [ + 80, + 199, + 176, + 244 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/f3b8980f8d7e10d8ff32851925089019a1d7608343c81c03f65c9d179db4efda.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 178, + 135, + 271, + 181 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/2ec54f5790388ed9254cd9fb1848553b4497c339c8fabf556eda75c28bded610.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 274, + 136, + 369, + 181 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/9c3c32a99fd22281b498cbf3ee65231f7c32d91408abb16fc479b7076b9ab860.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 370, + 136, + 465, + 181 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/10ebd9dda2a8f987720960a73ae5cacb16ac3c80f72ad539c995cb75e6a98e14.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 178, + 184, + 271, + 229 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/ce2af727ab62078d03844def69a37e0789c17e7dbbd030349423e33e658a3b60.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 274, + 184, + 369, + 229 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/2ccd32f87cc5d8e2f5506bfe3f07567ad948a59a77ad3e0f76f5b4a4182698e4.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 370, + 185, + 465, + 229 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/ef8f1e1c43e5f891870fbef2cb9d0c2e0f17a16290589157696f9e22fae02136.jpg", + "image_caption": [ + "Figure 3. (a) Example from MeViS. (b) Example from Refer-Youtu-VOS [44]. Compared to Refer-Youtu-VOS: $\\bullet$ Videos in MeViS contain more objects in complex environments, making it impossible to identify the target object via saliency or category information alone. $\\bullet$ The number of target objects indicated by language expression in MeViS is arbitrary, from 1 to many." + ], + "image_footnote": [], + "bbox": [ + 178, + 231, + 271, + 275 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/5b8e39569cd5fc3da8741927284d6d3611a7e4f594c36557d09743fbc948810d.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 274, + 231, + 367, + 275 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/80ee0ed1a600bacc2a803002840d59b20092e215e0db57c8c308499c84c16d39.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 370, + 231, + 465, + 275 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "category, such as a group of tigers or rabbits. For instance, in Figure 3(a), there are three giraffes with highly similar appearances, and the most salient foreground one is not the target object in this sample, making it challenging to identify the target object(s) through saliency or category information alone. By including more challenging videos, MeViS better simulates real-world scenarios, making it a valuable resource for studying motion expression-guided video understanding in complex environments.", + "bbox": [ + 75, + 380, + 468, + 517 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Target Object(s). As we have included longer videos in our MeViS dataset, we have also observed a significant increase in the duration of target objects, ensuring adequate object motions. As shown in Figure 2(b), the object durations in our dataset have an average of 10.88 seconds, which is more than two times longer than the average duration of Refer-Youtu-VOS. Compared to previous datasets, such as A2D Sentence [13] and J-HMDB Sentence [13], which focus on salient actions of a few categories [44], our MeViS dataset includes more categories from open-world [8, 42, 48, 51], presenting improved difficulties in the diversity of target objects. Besides, as shown in Table 1, previous datasets usually have one sentence referring to one single object, which means that finding multiple objects requires multiple expressions, and each object must be searched for individually*. In contrast, we add a more natural way of selecting target objects, where one expression may refer to several objects, denoted as \"multi-object expression\". An example of multi-object expression is shown in Figure 3(a), where \"Giraffes that turns around\" refers to two giraffes.", + "bbox": [ + 75, + 521, + 470, + 825 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/993fc699d1e1017ad8a285d37aa82df0cda92bccd4744b4f2c46c290fc8ea6c0.jpg", + "image_caption": [ + "Figure 4. Word cloud of the top 100 words in the MeViS dataset. MeViS has a large number of words that describe motions, like \"walking\", \"moving\", \"playing\", and many position words that are related to motions, such as \"left\", \"right\"." + ], + "image_footnote": [], + "bbox": [ + 506, + 89, + 880, + 233 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "As shown in Table 1, on average, each expression in MeViS refers to 1.59 objects, which is larger than existing datasets where the average is only 1 object per expression.", + "bbox": [ + 498, + 308, + 890, + 354 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Language Expression. One of the key distinguishing aspects of the MeViS dataset is its emphasis on describing object motions in language expressions. The previous largest RVOS dataset Refer-Youtu-VOS [44] provides two types of language annotations: full-video expression and first-frame expression. The first-frame expression is based solely on static attributes of the first frame image, whereas the full-video expression considers the entire video. However, in many cases, even the full-video expressions contain static attributes that could potentially enable the target object to be identified in a single frame, for example, \"A person on the right dressed in blue black...\". In contrast, to explore the practicality of employing motion expressions for object localization and segmentation in videos, MeViS is intentionally designed to include a range of diverse and dynamic object motions, making it more challenging to identify the target object based on static attributes alone. In MeViS, there are significantly more motion expressions that explicitly identify the target object based on its distinctive actions or movements. The language expressions in the proposed MeViS contain more motion attributes, such as object position moving through the video and actions that span several frames. The word cloud of the newly proposed MeViS is visualized in Figure 4. From the word cloud figure, we can observe that MeViS dataset has a large number of words that describe motions, like \"walking\", \"moving\", \"playing\", and many relative directions that are related to motions, such as \"left\", \"right\", etc.", + "bbox": [ + 496, + 357, + 892, + 781 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiment", + "text_level": 1, + "bbox": [ + 500, + 792, + 624, + 810 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Evaluation Metrics. Similar to previous studies such as [21,44], we employ two widely used metrics, $\\mathcal{I}$ and $\\mathcal{F}$ , to assess the performance of methods on the newly proposed MeViS dataset. The region similarity metric $\\mathcal{I}$ computes the Intersection over Union (IoU) of the predicted and", + "bbox": [ + 498, + 825, + 892, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_footnote", + "text": "*Although some datasets like $\\mathrm{DAVIS}_{16}$ -RVOS [21] contain samples of multiple instances as targets, the mask annotations provided by $\\mathrm{DAVIS}_{16}$ [40] do not distinguish instances, and some target masks cover several instances. Thus, each sample in $\\mathrm{DAVIS}_{16}$ -RVOS can be considered as a single-sentence single-object pair.", + "bbox": [ + 75, + 838, + 468, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "2698", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/1f64620243924b45063cb850c641de30fcfecd616222d6828f8e6637b563c69b.jpg", + "table_caption": [ + "Table 2. Temporal Context (TC) shows varying impacts on 3 datasets. Image-based methods, like VLT [10], can achieve state-of-the-art performance on $\\mathrm{DAVIS}_{17}$ -RVOS [21] and Refer-Youtu-VOS (RYV) [44], but cannot well handle the harder motion challenges in MeViS that require temporal context." + ], + "table_footnote": [], + "table_body": "
MethodsTypeTemporalDAVIS17-RVOSRYVMeViS
VLT [10]Image1 frame60.463.127.8
RFormer [55]Video5 rand. frames60.262.831.0
VLT+TCVideoAll frames60.362.735.5
RFormer+TCVideoAll frames59.963.036.3
", + "bbox": [ + 91, + 152, + 524, + 229 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "ground-truth masks, which reflects the quality of the segmentation. The F-measure $\\mathcal{F}$ reflects the contour accuracy of the prediction. To provide a comprehensive evaluation of the method's overall effectiveness, we calculate the average of these two metrics, denoted as $\\mathcal{J} \\& \\mathcal{F}$ .", + "bbox": [ + 75, + 241, + 470, + 316 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Dataset Setting. The MeViS dataset is a large-scale dataset that consists of a total of 2,006 videos along with 28,570 sentences. These videos are split into three subsets, i.e., training set, validation set, and testing set, which contain 1,712 videos, 140 videos, and 154 videos, respectively.", + "bbox": [ + 75, + 323, + 470, + 401 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Dataset Necessity and Challenges", + "text_level": 1, + "bbox": [ + 76, + 409, + 370, + 425 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To show the necessity and validity of MeViS in motion expression understanding, we compare the results of state-of-the-art referring image segmentation method VLT [10] and referring video segmentation method ReferFormer [55] on $\\mathrm{DAVIS}_{17}$ -RVOS [21], Refer-Youtu-VOS [44], and MeViS, as shown in Table 2. When trained on referring video segmentation dataset, such as Refer-Youtu-VOS [44] and testing on itself, the image-based method VLT [10] that does not use any temporal design can achieve exceptional results of $60.4\\%$ $\\mathcal{J} \\& \\mathcal{F}$ and $63.1\\%$ $\\mathcal{J} \\& \\mathcal{F}$ on video datasets $\\mathrm{DAVIS}_{17}$ -RVOS [21] and Refer-Youtu-VOS [44], respectively, which are even better than video method ReferFormer [55]. The results suggest that for $\\mathrm{DAVIS}_{17}$ -RVOS [21] and Refer-Youtu-VOS [44], the temporal context is not essential, and image-based methods that use static clues can achieve good performance on these two datasets. However, on the proposed MeViS, VLT [10] only achieves a score of $27.8\\%$ $\\mathcal{J} \\& \\mathcal{F}$ , suggesting that referring image segmentation methods without temporal designs struggle to address the unique challenges presented by videos in our dataset, particularly in handling motion, despite their success on other benchmark datasets. Furthermore, by comparing the results of VLT [10] with ReferFormer [55], which is trained using five randomly selected frames from the video, we find that ReferFormer outperforms VLT by a large margin of $3.2\\%$ in terms of $\\mathcal{J} \\& \\mathcal{F}$ . This further highlights the importance of analyzing long-term motions in the MeViS dataset. In order to further prove this point, we enhance VLT and ReferFormer by incorporating an attention module at the head to perceive and gather global temporal context (\"TC\" in Table 2).", + "bbox": [ + 73, + 431, + 472, + 902 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/328ef82cb218000e442417ebcaea7374e3b1e8111af8d9a889fdf7e931fc93da.jpg", + "table_caption": [ + "Table 3. Image-video cross-dataset validation. We train the models on referring image segmentation dataset Ref-COCO+/g, and test their performance on three different video datasets. The models trained on images perform worse on MeViS than on the other two datasets." + ], + "table_footnote": [], + "table_body": "
Training on Referring Image Segmentation Dataset
MethodsTypeDAVIS17-RVOSRYVMeViS
VLT [10]Image54.246.122.5
RFormer [55]Video55.645.227.0
", + "bbox": [ + 553, + 162, + 890, + 228 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "For module details, please refer to \"Motion Perception\" in Section 4.2. Adding temporal context via this module results in both VLT and ReferFormer achieving a performance gain of approximately $5\\%$ $\\mathcal{J}\\& \\mathcal{F}$ , underscoring the significance of temporal context for MeViS. However, it is worth noting that longer temporal information does not necessarily lead to better performance on $\\mathrm{DAVIS}_{17}$ -RVOS and Refer-Youtu-VOS.", + "bbox": [ + 496, + 241, + 890, + 361 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We also conduct a cross-dataset experiment by training on referring image segmentation datasets and testing on referring video segmentation datasets. The results in Table 3 show that both the image-based method VLT [10] and video-based method ReferFormer [55] achieve competitive results on Refer-Youtu-VOS [44] and $\\mathrm{DAVIS}_{17}$ -RVOS [21] when trained on image datasets Ref-COCO, Ref-COCO+, and Ref-COCOg. These results suggest that the expressions in Refer-Youtu-VOS [44] and DAVIS17-RVOS [21] provide static clues like in the image domain, and many target objects can be identified by examining a single frame solely. In contrast, when trained on referring image segmentation datasets and tested on MeViS, both VLT [10] and ReferFormer [55] perform worse, indicating that there is a significant expression-gap (e.g., static vs. motion) between MeViS and these image domain datasets.", + "bbox": [ + 496, + 363, + 892, + 606 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. LMPM: A Simple Baseline Approach", + "text_level": 1, + "bbox": [ + 498, + 619, + 823, + 635 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The MeViS dataset introduces unique challenges in detecting and understanding object motions in both video and language contexts. The motions described by language expressions can occur over a random number of frames, making it necessary to capture fleeting actions and movements that occur throughout the entire video. This presents significant challenges for recognizing motions in the video content and the corresponding language expressions. Detecting fleeting actions requires meticulous perceiving of every frame while comprehending complex and extended motion spanning multiple frames requires contextual understanding across the entire duration of the video. Current state-of-the-art methods, such as [2, 11, 55], rely on random sampling of a few frames, which may miss frames containing crucial information described by the given expression. Furthermore, these methods fail to effectively extract temporal contextual information and", + "bbox": [ + 496, + 643, + 893, + 901 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "2699", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/35c8dce7a0cdc952b19d53eaa1f125064dc2e8f988110c7388fed37fbc8f0a43.jpg", + "image_caption": [ + "Figure 5. The overview architecture of the proposed baseline approach Language-guided Motion Perception and Matching (LMPM). We first detect all possible target objects in each frame of the video and use object embeddings to represent them through Language-Guided Extractor. Then, Motion Perception is conducted on all the object embeddings of the video to grasp the global temporal context. By leveraging language queries and object embeddings with motion information, we generate object trajectories through a Transformer Decoder. Finally, we match the language features with the predicted object trajectories to identify the target object(s)." + ], + "image_footnote": [], + "bbox": [ + 83, + 88, + 890, + 262 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "instead simply use spatial-temporal feature extractors due to the significant burden on computational resources of temporal communication. Additionally, as illustrated in Section 3, objects described by language expressions can vary from one to multiple, requiring the output to cover from one to an arbitrary number of objects.", + "bbox": [ + 75, + 361, + 470, + 452 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "To address the challenges posed by the MeViS dataset, we propose a baseline approach called Language-guided Motion Perception and Matching (LMPM), which is depicted in Figure 5. LMPM generates $N_{1}$ language-based queries to identify potential target objects in the video, across $T$ frames, and produces object embeddings to represent each of them. Using language queries instead of conventional object queries can filter out irrelevant objects and ensure the efficiency and effectiveness of subsequent operations [9, 10]. Inspired by VITA [15], we represent objects using object embeddings, which provide instance-specific information, to reduce computational requirements [24, 25]. After obtaining object embeddings from frames in the video, we perform motion perception by inter-frame self-attention on the object embeddings to obtain a global view across $T$ frames. Motion perception enables object embeddings to capture temporal contextual information that spans multiple frames, or even the entire video. Then, we use $N_{2}$ language queries as the query and the object embeddings after Motion Perception as the key and value for the Transformer decoder. The Transformer decoder decodes language-related information from all object embeddings and aggregates relevant information to predict object trajectories. Finally, we match the language features with the predicted object trajectories to identify the target object(s). Rather than only selecting the best-matched object trajectory, we use a matching threshold $\\sigma$ to choose object trajectories only if their similarity with the language features exceeds the threshold $\\sigma$ . This enables the model", + "bbox": [ + 75, + 462, + 470, + 900 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/5ad0bc24b72a260829d1d5fe8513de46d3187f26d1bb1d89f0d2c501241112b0.jpg", + "table_caption": [ + "Table 4. Ablation study of the baseline approach LMPM." + ], + "table_footnote": [], + "table_body": "
IDLanguage QueryMotion PerceptionMatchingJ&F
i✓××31.0
ii✓✓×36.3
iii✓✓✓37.2
", + "bbox": [ + 506, + 376, + 885, + 443 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "to handle not only single-object expressions but also multi-object expressions, which is a unique feature of MeViS.", + "bbox": [ + 498, + 449, + 890, + 479 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Implementation Details. We set all the hyper-parameters related to the Language-Guided Extractor to the default settings of Mask2Former [4], including the backbone, Transformer decoder. We train 150,000 iterations using AdamW optimizer [35] with a learning rate of 0.00005. Tiny Swin Transformer [33] is employed as our backbone in all the experiments. The input frames are resized to have a minimum size of 448 pixels on the shorter side during inference. Motion Perception consists of six layers, and the Transformer decoder employs three layers. For the hyperparameter settings, we set $\\sigma$ , $N_{1}$ and $N_{2}$ to 0.8, 20, and 10, respectively. We use RoBERTa [32] as a text encoder that is consistent with the ReferFormer and is frozen all the time.", + "bbox": [ + 496, + 486, + 892, + 681 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Ablation study of LMPM. In Table 4, we present an ablation study of the baseline approach LMPM. We perform the following three experiments: (i) First, we use language queries to detect potential target object trajectories and output the best trajectory, similar to ReferFormer [55]. This variant achieves a $\\mathcal{J}\\& \\mathcal{F}$ score of $31.0\\%$ . It relies solely on language information with 5 randomly sampled frames and neglects global temporal context across the video, making it unable to effectively process long-term motions. (ii) With the help of Motion Perception, the $\\mathcal{J}\\& \\mathcal{F}$ score significantly improves by $5.3\\%$ , as it captures temporal contextual information and a global view of the entire video, which are critical for MeViS. (iii) Since MeViS contains multi-objects expressions, outputting only the object with", + "bbox": [ + 496, + 688, + 893, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "2700", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/93a96be995b8746bdf45bad313341efddd5470aba9ac4ba75c2b954b6730c4b7.jpg", + "table_caption": [ + "Table 5. MeViS Benchmark Results." + ], + "table_footnote": [], + "table_body": "
MethodsJ&FJF
URVOS [44]27.825.729.9
LBDT [11]29.327.830.8
MTTR [2]30.028.831.2
ReferFormer [55]31.029.832.2
VLT+TC [10]35.533.637.3
LMPM (ours)37.234.240.2
", + "bbox": [ + 80, + 104, + 467, + 208 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "the highest score is insufficient. We introduce a matching mechanism to identify the target object(s), enabling our method to handle not only single-object expressions but also multi-object expressions. This variant outperforms (ii) by $0.9\\%$ in terms of $\\mathcal{J}\\& \\mathcal{F}$ score.", + "bbox": [ + 75, + 232, + 468, + 308 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.3. MeViS Benchmark Results", + "text_level": 1, + "bbox": [ + 76, + 321, + 320, + 335 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Quantitative results. We performed a comprehensive evaluation of the MeViS dataset to assess the performance of existing methods in the more challenging motion-expression scenarios. We evaluated 1 modified image-based method VLT [10] and 4 recent state-of-the-art video-based methods, including URVOS [44], LBDT [11], MTTR [2], and ReferFormer [55], on the validation set $^{\\dagger}$ of MeViS. The evaluation results, presented in Table 5, indicate that the current state-of-the-art methods could only achieve performance ranging from $27.8\\%$ $\\mathcal{J}\\& \\mathcal{F}$ to $31.0\\%$ $\\mathcal{J}\\& \\mathcal{F}$ on the validation set of MeViS, while their results on other benchmarks like Refer-Youtu-VOS [44] and DAVIS $_{17}$ -RVOS [21] are usually above $60\\%$ $\\mathcal{J}\\& \\mathcal{F}$ . Our experiments demonstrate that while notable progress has been made in language-guided video object segmentation on existing benchmarks, the challenges presented by MeViS underline the need for further exploration of motion expression-guided video segmentation in complex scenarios. These challenges can arise from various factors, including both linguistic and visual modalities, such as the use of motion expressions and highly dynamic objects or fast-paced motions in videos, which can impact the overall performance of algorithms.", + "bbox": [ + 75, + 343, + 468, + 676 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Visualizations. Figure 6 displays some of the success and failure cases of the baseline approach LMPM. Example (a) and (b) depict successful cases where LMPM effectively processes expressions of long-term motions such as \"moving to the front ...\" and \"goes out of the screen\". In contrast, example (c) and (d) are failure cases. In example (c), the expression involves the target object disappearing and reappearing, which poses a significant challenge for the model's global understanding of the video. In this case, our model becomes disoriented after the target object reappears. Example (d) shows a sentence describing a long-term motion while involving multiple target objects. Our method successfully identifies the multiple targets, i.e., the", + "bbox": [ + 75, + 681, + 468, + 878 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/58f8e788fb86e04d6894ac76c8076d5a0567f8c85605d33759136bd191c7405c.jpg", + "image_caption": [ + "(a). \"The monkey moving to the front of another monkey, and turning\"" + ], + "image_footnote": [], + "bbox": [ + 501, + 89, + 888, + 127 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/320ef5dd75b619d0406fa231e31187eaf0c3e7c116dd517032f9a2495cfeaf00.jpg", + "image_caption": [ + "(b). \"The panda that goes out of the screen towards left\"" + ], + "image_footnote": [], + "bbox": [ + 503, + 138, + 888, + 176 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/9f67730a70d4fea923e3c87690148a83ca422782ec79a7dad0c269fbd1d7e920.jpg", + "image_caption": [ + "(c). \"The dog that disappears from left, then re-appears\"" + ], + "image_footnote": [], + "bbox": [ + 503, + 186, + 888, + 224 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/a053ab9b8e2b4ffb8a78a07c8e622f5877b5cf822b8c5cf67dc2c2832c9846e4.jpg", + "image_caption": [ + "(d). \"Two goats walking from the distance to the front, then turning back\"", + "Figure 6. Example success and failure cases of LMPM." + ], + "image_footnote": [], + "bbox": [ + 503, + 237, + 888, + 281 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "\"two goats walking from the distance\", at the beginning of the video. However, one of the targets is lost during the later stages of the video when the motions of objects became complex and tangled. These two failure cases demonstrate the complexity and challenges of MeViS, emphasizing the importance of a strong ability to comprehend the global temporal context of the entire video and to understand the motion expression for models working on MeViS.", + "bbox": [ + 496, + 329, + 890, + 450 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusion and Discussion", + "text_level": 1, + "bbox": [ + 500, + 465, + 746, + 481 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "The ability to effectively understand and leverage motion expressions as a primary cue for object segmentation in videos remains an unresolved challenge that requires attention in future research. The proposed large-scale benchmark MeViS provides a foundation for developing more advanced language-guided video segmentation algorithms.", + "bbox": [ + 496, + 492, + 890, + 582 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Future Directions. There are many interesting research directions and remaining challenges to be addressed with the MeViS dataset. These include but are not limited to: (i) exploring new techniques for better motion understanding and modeling in both visual and linguistic modalities, (ii) designing more elegant and robust models that can effectively handle diverse motion types spanning across a range of frames, including long-term/short-term and complex motions, (iii) developing advanced models that can handle complex scenes with various types of objects and expressions, (iv) creating more efficient models that can effectively reduce the number of redundant detected objects, (v) designing effective cross-modal fusion methods to better leverage the complementary information between language and visual signals, (vi) investigating the potential of transfer learning and domain adaptation in language-guided video segmentation, and (vii) developing methods that can better handle the open-world concepts in both the visual and linguistic domain. These challenges require significant research efforts to advance the state-of-the-art in language-guided video segmentation.", + "bbox": [ + 496, + 583, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_footnote", + "text": "The test set is utilized for evaluation during the competition periods.", + "bbox": [ + 94, + 886, + 460, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "2701", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgement. This study is supported under the RIE2020 Industry Alignment Fund - Industry Collaboration Projects (IAF-ICP) Funding Initiative, as well as cash and in-kind contribution from the industry partner(s). This study is also supported by the research grant of NTU Presidential Postdoctoral Fellowship. The data of MeViS is released for non-commercial research purposes only.", + "bbox": [ + 76, + 92, + 472, + 167 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 176, + 173, + 193 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Miriam Bellver, Carles Ventura, Carina Silberer, Ioannis Kazakos, Jordi Torres, and Xavier Giro-i Nieto. A closer look at referring expressions for video object segmentation. Multimedia Tools and Applications, 2022. 2, 3", + "[2] Adam Botach, Evgenii Zheltonozhskii, and Chaim Baskin. End-to-end referring video object segmentation with multimodal transformers. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 2, 3, 6, 8", + "[3] Weidong Chen, Dexiang Hong, Yuankai Qi, Zhenjun Han, Shuhui Wang, Laiyun Qing, Qingming Huang, and Guorong Li. Multi-attention network for compressed video referring object segmentation. In ACM Int. Conf. Multimedia, 2022. 3", + "[4] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 7", + "[5] Henghui Ding, Scott Cohen, Brian Price, and Xudong Jiang. PhraseClick: toward achieving flexible interactive segmentation by phrase and click. In Proc. Eur. Conf. Comput. Vis., 2020. 2", + "[6] Henghui Ding, Xudong Jiang, Ai Qun Liu, Nadia Magnenat Thalmann, and Gang Wang. Boundary-aware feature propagation for scene segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2019. 2", + "[7] Henghui Ding, Xudong Jiang, Bing Shuai, Ai Qun Liu, and Gang Wang. Context contrasted feature and gated multi-scale aggregation for scene segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 2", + "[8] Henghui Ding, Chang Liu, Shuting He, Xudong Jiang, Philip HS Torr, and Song Bai. MOSE: A new dataset for video object segmentation in complex scenes. In Proc. IEEE Int. Conf. Comput. Vis., 2023. 3, 5", + "[9] Henghui Ding, Chang Liu, Suchen Wang, and Xudong Jiang. Vision-language transformer and query generation for referring segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2021. 2, 3, 7", + "[10] Henghui Ding, Chang Liu, Suchen Wang, and Xudong Jiang. VLT: Vision-language transformer and query generation for referring segmentation. IEEE Trans. Pattern Anal. Mach. Intell., 2023. 2, 3, 6, 7, 8", + "[11] Zihan Ding, Tianrui Hui, Junshi Huang, Xiaoming Wei, Jizhong Han, and Si Liu. Language-bridged spatial-temporal interaction for referring video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 2, 6, 8", + "[12] Guang Feng, Zhiwei Hu, Lihe Zhang, and Huchuan Lu. Encoder fusion network with co-attention embedding for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 2", + "[13] Kirill Gavrilyuk, Amir Ghodrati, Zhenyang Li, and Cees GM Snoek. Actor and action video segmentation from a sentence. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 1, 2, 3, 4, 5", + "[14] Kaiming He, Georgia Gkioxari, Piotr Dollar, and Ross Girshick. Mask r-cnn. In Proc. IEEE Int. Conf. Comput. Vis., 2017. 2", + "[15] Miran Heo, Sukjun Hwang, Seoung Wug Oh, Joon-Young Lee, and Seon Joo Kim. Vita: Video instance segmentation via object token association. In Proc. Adv. Neural Inform. Process. Syst., 2022. 2, 7", + "[16] Ronghang Hu, Marcus Rohrbach, and Trevor Darrell. Segmentation from natural language expressions. In Proc. Eur. Conf. Comput. Vis., 2016. 2" + ], + "bbox": [ + 78, + 202, + 468, + 898 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[17] Tianrui Hui, Shaofei Huang, Si Liu, Zihan Ding, Guanbin Li, Wenguan Wang, Jizhong Han, and Fei Wang. Collaborative spatial-temporal modeling for language-queried video actor segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 3", + "[18] Tianrui Hui, Si Liu, Shaofei Huang, Guanbin Li, Sansi Yu, Faxi Zhang, and Jizhong Han. Linguistic structure guided context modeling for referring image segmentation. In Proc. Eur. Conf. Comput. Vis., 2020. 3", + "[19] Ya Jing, Tao Kong, Wei Wang, Liang Wang, Lei Li, and Tieniu Tan. Locate then segment: A strong pipeline for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 2", + "[20] Sahar Kazemzadeh, Vicente Ordonez, Mark Matten, and Tamara Berg. ReferItGame: Referring to objects in photographs of natural scenes. In Proc. of the Conf. on Empirical Methods in Natural Language Process., Doha, Qatar, 2014. Association for Computational Linguistics. 2, 3", + "[21] Anna Khoreva, Anna Rohrbach, and Bernt Schiele. Video object segmentation with language referring expressions. In Proc. Asi. Conf. Comput. Vis., 2018. 1, 2, 3, 4, 5, 6, 8", + "[22] Namyup Kim, Dongwon Kim, Cuiling Lan, Wenjun Zeng, and Suha Kwak. Restr: Convolution-free referring image segmentation using transformers. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3", + "[23] Ruiyu Li, Kaican Li, Yi-Chun Kuo, Michelle Shu, Xiaojuan Qi, Xiaoyong Shen, and Jiaya Jia. Referring image segmentation via recurrent refinement networks. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 2", + "[24] Xiangtai Li, Henghui Ding, Wenwei Zhang, Haobo Yuan, Jiangmiao Pang, Guangliang Cheng, Kai Chen, Ziwei Liu, and Chen Change Loy. Transformer-based visual segmentation: A survey. arXiv preprint arXiv:2304.09854, 2023. 7", + "[25] Xiangtai Li, Haobo Yuan, Wenwei Zhang, Guangliang Cheng, Jiangmiao Pang, and Chen Change Loy. Tube-link: A flexible cross tube baseline for universal video segmentation. ICCV, 2023. 7", + "[26] Chen Liang, Yu Wu, Tianfei Zhou, Wenguan Wang, Zongxin Yang, Yunchao Wei, and Yi Yang. Rethinking cross-modal interaction from a top-down perspective for referring video object segmentation. arXiv preprint arXiv:2106.01061, 2021. 3", + "[27] Chang Liu, Henghui Ding, and Xudong Jiang. GRES: Generalized referring expression segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2023. 2", + "[28] Chang Liu, Henghui Ding, Yulun Zhang, and Xudong Jiang. Multimodal mutual attention and iterative interaction for referring image segmentation. IEEE Trans. Image Processing, 2023. 2", + "[29] Chang Liu, Xudong Jiang, and Henghui Ding. Instance-specific feature propagation for referring segmentation. IEEE Trans. Multimedia, 2022. 2", + "[30] Chenxi Liu, Zhe Lin, Xiaohui Shen, Jimei Yang, Xin Lu, and Alan Yuille. Recurrent multimodal interaction for referring image segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2017. 2", + "[31] Si Liu, Tianrui Hui, Shaofei Huang, Yunchao Wei, Bo Li, and Guanbin Li. Cross-modal progressive comprehension for referring segmentation. IEEE Trans. Pattern Anal. Mach. Intell., 2021. 2, 3", + "[32] Yinhan Liu, Myle Ott, Naman Goyal, Jingfei Du, Mandar Joshi, Danqi Chen, Omer Levy, Mike Lewis, Luke Zettlemoyer, and Veselin Stoyanov. Roberta: A robustly optimized bert pretraining approach. arXiv preprint arXiv:1907.11692, 2019. 7", + "[33] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proc. IEEE Int. Conf. Comput. Vis., 2021. 7", + "[34] Jonathan Long, Evan Shelhamer, and Trevor Darrell. Fully convolutional networks for semantic segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2015. 2" + ], + "bbox": [ + 501, + 93, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "2702", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[35] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In Proc. Int. Conf. Learn. Represent., 2019. 7", + "[36] Junhua Mao, Jonathan Huang, Alexander Toshev, Oana Camburu, Alan L Yuille, and Kevin Murphy. Generation and comprehension of unambiguous object descriptions. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2016. 2", + "[37] Edgar Margffoy-Tuay, Juan C Pérez, Emilio Botero, and Pablo Arbeláez. Dynamic multimodal instance segmentation guided by natural language queries. In Proc. Eur. Conf. Comput. Vis., 2018. 2", + "[38] Bruce McIntosh, Kevin Duarte, Yogesh S Rawat, and Mubarak Shah. Visual-textual capsule routing for text-based video segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2020. 3", + "[39] Ke Ning, Lingxi Xie, Fei Wu, and Qi Tian. Polar relative positional encoding for video-language segmentation. In IJCAI, 2020. 3", + "[40] Federico Perazzi, Jordi Pont-Tuset, Brian McWilliams, Luc Van Gool, Markus Gross, and Alexander Sorkine-Hornung. A benchmark dataset and evaluation methodology for video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2016. 5", + "[41] Jordi Pont-Tuset, Federico Perazzi, Sergi Caelles, Pablo Arbeláez, Alex Sorkine-Hornung, and Luc Van Gool. The 2017 davis challenge on video object segmentation. arXiv preprint arXiv:1704.00675, 2017.3", + "[42] Jiyang Qi, Yan Gao, Yao Hu, Xinggang Wang, Xiaoyu Liu, Xiang Bai, Serge Belongie, Alan Yuille, Philip HS Torr, and Song Bai. Occluded video instance segmentation: A benchmark. Int. J. Comput. Vis., 130(8), 2022. 3, 5", + "[43] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In Proc. Int. Conf. Mach. Learn., 2021. 3", + "[44] Seonguk Seo, Joon-Young Lee, and Bohyung Han. Urvos: Unified referring video object segmentation network with a large-scale benchmark. In Proc. Eur. Conf. Comput. Vis., 2020. 1, 2, 3, 4, 5, 6, 8", + "[45] Mingjie Sun, Jimin Xiao, Eng GEE Lim, and Yao Zhao. Starting point selection and multiple-standard matching for video object segmentation with language annotation. IEEE Trans. Multimedia, 2022. 3", + "[46] Zongheng Tang, Yue Liao, Si Liu, Guanbin Li, Xiaojie Jin, Hongxu Jiang, Qian Yu, and Dong Xu. Human-centric spatio-temporal video grounding with visual transformers. IEEE Trans. Circuit Syst. Video Technol., 2021. 3", + "[47] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Proc. Adv. Neural Inform. Process. Syst., 2017. 3", + "[48] Paul Voigtlaender, Lishu Luo, Chun Yuan, Yong Jiang, and Bastian Leibe. Reducing the annotation effort for video object segmentation datasets. In Proc. IEEE Winter Conf. Appl. Comput. Vis., 2021. 3, 5" + ], + "bbox": [ + 78, + 93, + 468, + 738 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[49] Hao Wang, Cheng Deng, Fan Ma, and Yi Yang. Context modulated dynamic networks for actor and action video segmentation with language queries. In AAAI, 2020. 3", + "[50] Hao Wang, Cheng Deng, Junchi Yan, and Dacheng Tao. Asymmetric cross-guided attention network for actor and action video segmentation from natural language query. In Proc. IEEE Int. Conf. Comput. Vis., 2019. 3", + "[51] Weiyao Wang, Matt Feiszli, Heng Wang, and Du Tran. Unidentified video objects: A benchmark for dense, open-world segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2021. 3, 5", + "[52] Zhaoqing Wang, Yu Lu, Qiang Li, Xunqiang Tao, Yandong Guo, Mingming Gong, and Tongliang Liu. Cris: Clip-driven referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3", + "[53] Chenyun Wu, Zhe Lin, Scott Cohen, Trung Bui, and Subhransu Maji. Phrasecut: Language-based image segmentation in the wild. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2020. 2", + "[54] Dongming Wu, Xingping Dong, Ling Shao, and Jianbing Shen. Multi-level representation learning with semantic alignment for referring video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3", + "[55] Jiannan Wu, Yi Jiang, Peize Sun, Zehuan Yuan, and Ping Luo. Language as queries for referring video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 2, 3, 6, 7, 8", + "[56] Ning Xu, Linjie Yang, Yuchen Fan, Dingcheng Yue, Yuchen Liang, Jianchao Yang, and Thomas Huang. Youtube-vos: A large-scale video object segmentation benchmark. arXiv preprint arXiv:1809.03327, 2018.3,4", + "[57] Antoine Yang, Antoine Miech, Josef Sivic, Ivan Laptev, and Cordelia Schmid. Tubedetr: Spatio-temporal video grounding with transformers. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3", + "[58] Sibei Yang, Meng Xia, Guanbin Li, Hong-Yu Zhou, and Yizhou Yu. Bottom-up shift and reasoning for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 3", + "[59] Zhao Yang, Jiaqi Wang, Yansong Tang, Kai Chen, Hengshuang Zhao, and Philip HS Torr. Levt: Language-aware vision transformer for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3", + "[60] Linwei Ye, Mrigank Rochan, Zhi Liu, and Yang Wang. Cross-modal self-attention network for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2019. 3", + "[61] Licheng Yu, Zhe Lin, Xiaohui Shen, Jimei Yang, Xin Lu, Mohit Bansal, and Tamara L Berg. Mattnet: Modular attention network for referring expression comprehension. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 2, 3", + "[62] Licheng Yu, Patrick Poirson, Shan Yang, Alexander C Berg, and Tamara L Berg. Modeling context in referring expressions. In Proc. Eur. Conf. Comput. Vis., 2016. 2", + "[63] Wangbo Zhao, Kai Wang, Xiangxiang Chu, Fuzhao Xue, Xinchao Wang, and Yang You. Modeling motion with multi-modal features for text-based video segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + ], + "bbox": [ + 501, + 93, + 890, + 738 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "2703", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/422d1f87-df33-4f64-91c1-e11c03538001_model.json b/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/422d1f87-df33-4f64-91c1-e11c03538001_model.json new file mode 100644 index 0000000000000000000000000000000000000000..ba6361886683a964a9ab47b04c3c3390633bddcc --- /dev/null +++ b/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/422d1f87-df33-4f64-91c1-e11c03538001_model.json @@ -0,0 +1,2486 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.191, + 0.131, + 0.78, + 0.176 + ], + "angle": 0, + "content": "MeViS: A Large-scale Benchmark for Video Segmentation with Motion Expressions" + }, + { + "type": "text", + "bbox": [ + 0.1, + 0.203, + 0.87, + 0.258 + ], + "angle": 0, + "content": "Henghui Ding† Chang Liu‡ Shuting He‡ Xudong Jiang‡ Chen Change Loy† \n†S-Lab, Nanyang Technological University ‡School of EEE, Nanyang Technological University https://henghuiding.github.io/MeViS" + }, + { + "type": "image_caption", + "bbox": [ + 0.105, + 0.291, + 0.173, + 0.302 + ], + "angle": 0, + "content": "First Frame" + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.303, + 0.197, + 0.353 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.474, + 0.289, + 0.605, + 0.302 + ], + "angle": 0, + "content": "\"The bird flying away\"" + }, + { + "type": "image", + "bbox": [ + 0.2, + 0.303, + 0.315, + 0.353 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.316, + 0.303, + 0.429, + 0.353 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.429, + 0.303, + 0.543, + 0.353 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.543, + 0.303, + 0.657, + 0.353 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.658, + 0.303, + 0.772, + 0.353 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.773, + 0.303, + 0.888, + 0.353 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.451, + 0.356, + 0.64, + 0.37 + ], + "angle": 0, + "content": "\"The cat playing with the teaser\"" + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.369, + 0.196, + 0.42 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.2, + 0.369, + 0.315, + 0.42 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.316, + 0.369, + 0.429, + 0.419 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.43, + 0.369, + 0.544, + 0.419 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.544, + 0.369, + 0.657, + 0.419 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.658, + 0.369, + 0.772, + 0.419 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.773, + 0.369, + 0.888, + 0.42 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.375, + 0.423, + 0.715, + 0.436 + ], + "angle": 0, + "content": "\"Bears that walk forwards from left to right then walk back\"" + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.436, + 0.197, + 0.486 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.201, + 0.436, + 0.315, + 0.486 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.316, + 0.436, + 0.429, + 0.486 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.429, + 0.436, + 0.543, + 0.486 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.543, + 0.436, + 0.657, + 0.486 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.658, + 0.436, + 0.772, + 0.486 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.773, + 0.436, + 0.888, + 0.486 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.492, + 0.893, + 0.548 + ], + "angle": 0, + "content": "Figure 1. Examples of video clips from Motion expressions Video Segmentation (MeViS) are provided to illustrate the dataset's nature and complexity. The expressions in MeViS primarily focus on motion attributes and the referred target object cannot be identified by examining a single frame solely. For instance, the first example features three parrots with similar appearances, and the target object is identified as \"The bird flying away\". This object can only be recognized by capturing its motion throughout the video." + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.566, + 0.314, + 0.582 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.592, + 0.471, + 0.88 + ], + "angle": 0, + "content": "This paper strives for motion expressions guided video segmentation, which focuses on segmenting objects in video content based on a sentence describing the motion of the objects. Existing referring video object datasets typically focus on salient objects and use language expressions that contain excessive static attributes that could potentially enable the target object to be identified in a single frame. These datasets downplay the importance of motion in video content for language-guided video object segmentation. To investigate the feasibility of using motion expressions to ground and segment objects in videos, we propose a large-scale dataset called MeViS, which contains numerous motion expressions to indicate target objects in complex environments. We benchmarked 5 existing referring video object segmentation (RVOS) methods and conducted a comprehensive comparison on the MeViS dataset. The results show that current RVOS methods cannot effectively address motion expression-guided video segmentation. We further analyze the challenges and propose a baseline" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.568, + 0.895, + 0.674 + ], + "angle": 0, + "content": "approach for the proposed MeViS dataset. The goal of our benchmark is to provide a platform that enables the development of effective language-guided video segmentation algorithms that leverage motion expressions as a primary cue for object segmentation in complex video scenes. The proposed MeViS dataset has been released at https://henghuiding.github.io/MeViS." + }, + { + "type": "title", + "bbox": [ + 0.502, + 0.708, + 0.633, + 0.723 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.894, + 0.901 + ], + "angle": 0, + "content": "Language-guided video segmentation is an emerging field that involves segmenting and tracking target objects using natural language expressions. This field has traditionally been a sub-branch of semi-supervised video object segmentation, where referring expressions are used to describe the target object. Existing referring video object datasets, such as [13,21,44], commonly feature videos with isolated and salient objects that have obvious static features. The corresponding expressions often contain static attributes such as object color, which can be observed in a single frame. As a result, motion properties of videos are often" + }, + { + "type": "page_footnote", + "bbox": [ + 0.1, + 0.888, + 0.359, + 0.901 + ], + "angle": 0, + "content": "henghui.ding@gmail.com, ccloy@ntu.edu.sg" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2694" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.08, + 0.092, + 0.467, + 0.137 + ], + "angle": 0, + "content": "given less emphasis, and referring image segmentation methods can be used for referring video segmentation, achieving good results [1, 10, 21, 31]." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.139, + 0.467, + 0.26 + ], + "angle": 0, + "content": "In this paper, we wish to highlight the significance of temporal motion properties of videos and explore the potential of using motion expressions to segment objects in videos. To this end, we propose a new large-scale dataset called Motion expressions Video Segmentation (MeViS) to aid our investigation. The MeViS dataset comprises 2,006 videos with a total of 8,171 objects, and 28,570 motion expressions are provided to refer to these objects." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.262, + 0.467, + 0.579 + ], + "angle": 0, + "content": "We take several steps to ensure that the MeViS dataset places emphasis on the temporal motions of videos. First, we carefully select video content that contains multiple objects that coexist with motion and exclude videos with isolated objects that can be easily described by static attributes. Second, we prioritize language expressions that do not contain static clues, such as category names or object colors, in cases where target objects can be unambiguously described by motion words alone. This is distinct from previous datasets, such as [13, 21, 44], which include obvious static clues in their expressions. Additionally, MeViS differentiates itself from referring image segmentation datasets, such as [20, 36, 53, 62], which do not account for the temporal properties of video content. Moreover, unlike existing referring video object segmentation datasets that focus on single-target expressions, where one expression refers to only one target object, MeViS expands this task to include multi-object expressions that refer to multiple target objects. This feature enables expressions to refer to an unlimited number of target objects, making the proposed MeViS more challenging and reflective of real-world scenarios." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.582, + 0.467, + 0.853 + ], + "angle": 0, + "content": "The proposed MeViS dataset poses notable challenges in capturing and understanding motions in both video and language. The language expressions may describe motion that spans a random number of frames, requiring the capture of fleeting movements and long-term actions that occur throughout the entire video. This poses significant challenges for both understanding motion in the video content and in the accompanying language expressions. Capturing fleeting movements requires attention on each individual frame, while understanding long and complex movements that span across many frames demands temporal context across the entire video. With the proposed dataset, we benchmark 5 existing referring video object segmentation (RVOS) methods [2, 10, 11, 44, 55] and conduct a comprehensive comparison. The experimental results demonstrate that MeViS presents more challenges than existing datasets, and current RVOS methods are unable to effectively address motion expression-guided video segmentation." + }, + { + "type": "text", + "bbox": [ + 0.08, + 0.856, + 0.467, + 0.9 + ], + "angle": 0, + "content": "In addition to proposing the MeViS dataset, we present a baseline approach, named Language-guided Motion Perception and Matching (LMPM), to address the challenges" + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.092, + 0.89, + 0.287 + ], + "angle": 0, + "content": "posed by the dataset. Our approach generates language-conditional queries to detect potential target objects in the video and represents them using object embeddings, which are more robust and computationally efficient than object feature maps [15]. We then perform Motion Perception on the object embeddings to capture the temporal context and obtain a global view of the video, enabling the model to understand both fleeting and long-term motions. Next, we use a Transformer decoder to decode language-related information from the motion-aggregated object embeddings and predict object trajectories. Finally, we perform similarity matching between the language features and the predicted object trajectories to identify the target object(s)." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.289, + 0.89, + 0.453 + ], + "angle": 0, + "content": "Our contributions provide a foundation for developing more advanced language-guided video segmentation algorithms that leverage motion expressions as a primary cue for object segmentation and identification in complex video scenes. In particular, we propose a new language-guided video segmentation dataset, MeViS, and conduct comprehensive evaluations of state-of-the-art referring video object segmentation methods on the MeViS dataset, providing a reference for future works. We also develop a simple baseline approach, LMPM, which points to potential solutions to some of the challenges and future research directions." + }, + { + "type": "title", + "bbox": [ + 0.504, + 0.468, + 0.64, + 0.484 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.493, + 0.89, + 0.809 + ], + "angle": 0, + "content": "Referring Image Segmentation. Referring image segmentation [5, 9, 10, 27, 28], also known as referring expression segmentation, involves grounding the target object in images based on natural language expressions that describe its properties and generating a corresponding segmentation mask. This task requires both language and image understanding and is one of the most fundamental yet challenging tasks in computer vision. Referring image segmentation was first introduced by Hu et al. [16] in 2016 and has received considerable attention since then. In the preTransformer era, mainstream methods typically employed Fully Convolutional Networks (FCN) [6, 7, 34] and Recurrent Neural Networks (RNN) to extract image features and language features, respectively, and then fused the multimodal features via some specially designed modules [12, 23, 30, 37]. For example, Liu et al. [30] introduced a Recurrent Multimodal Interaction (RMI) module to recurrently fuse the feature of each word into the image features. Li et al. [23] proposed a Recurrent Refinement Network (RRN) that progressively refines the segmentation mask based on pyramid features in FCN." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.811, + 0.89, + 0.899 + ], + "angle": 0, + "content": "In addition to one-stage methods that fuse multi-modal features and conduct segmentation, some methods decouple referring image segmentation into instance segmentation and language-object matching [19, 29, 61]. For instance, Yu et al. use the off-the-shelf instance segmentation model Mask R-CNN [14] to detect all instances first and then" + }, + { + "type": "page_number", + "bbox": [ + 0.485, + 0.947, + 0.514, + 0.957 + ], + "angle": 0, + "content": "2695" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.362 + ], + "angle": 0, + "content": "select the one that best matches the language as output. A holistic understanding of language and vision information is crucial for referring image segmentation, and many works have explored this direction [18, 58, 60]. For instance, Ye et al. introduce a Cross-Modal Self-Attention (CMSA) model [60] to select the most meaningful words in the expression and pixels in the image to achieve better contextual understanding. Recently, the success of Transformer [47] in vision tasks has inspired many studies in referring image segmentation. Ding et al. [9, 10] first introduced Transformer into referring segmentation and proposed a Vision-Language Transformer (VLT). Following Ding et al. [9, 10], more Transformer-based methods have been proposed [22, 52, 59]. For example, Wang et al. [52] employ the Vision-Language Decoder to deal with visual and text tokens extracted by CLIP [43]. Yang et al. [59] focus on multi-modal feature fusion and propose a Language-Aware Vision Transformer (LAVT)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.364, + 0.473, + 0.575 + ], + "angle": 0, + "content": "Referring Video Segmentation. Referring video object segmentation is an emerging area [3, 17, 31, 38, 39, 45, 46, 49, 50, 54, 57, 63] that aims to segment the target object indicated by a given expression across the entire video clip. It was first introduced in 2018 by A2D [13] and DAVIS17-RVOS [21], where A2D [13] seeks to segment actors according to descriptions of their actions in video content, and DAVIS17-RVOS [21] replaces masks with language as the reference for the target object in video object segmentation. Later, Seo et al. [44] built the Refer-YouTube-VOS based on the YouTube-VOS-2019 dataset [56]. These datasets typically provide an expression for a single object, and the expression usually describes the static attributes of the target object, such as its color and shape." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.576, + 0.473, + 0.834 + ], + "angle": 0, + "content": "Existing methods typically treat referring video segmentation as a form of semi-supervised video object segmentation [41] by replacing mask reference with language reference. For instance, Khoreva et al. [21] employ the referring image segmentation method MAttNet [61] to achieve frame-level segmentation and then perform post-processing for temporal consistency. URVOS [44] employs cross-modal attention to perform per-frame segmentation and propagate the mask across clips with a memory attention module. RefVOS [1] independently segments each frame based on the fused features of language and image/frame, without utilizing temporal information. Liang et al. [26] introduces a top-down approach that first detects all object tracklets and then selects the target object by matching between language and tracklet features. Most recently, ReferFormer [55] and MTTR [2] employ Transformer [47] to address referring video object segmentation." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.846, + 0.229, + 0.862 + ], + "angle": 0, + "content": "3. MeViS Dataset" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.472, + 0.903 + ], + "angle": 0, + "content": "In this section, we introduce the newly built large-scale dataset MeViS by first presenting the video collection and" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.123 + ], + "angle": 0, + "content": "annotation process in Section 3.1 and then providing the dataset statistics and analysis in Section 3.2." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.13, + 0.774, + 0.146 + ], + "angle": 0, + "content": "3.1. Motion Expression Annotation" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.159, + 0.894, + 0.235 + ], + "angle": 0, + "content": "Video Collection. We gather and choose videos from publicly available video segmentation datasets with high-quality mask annotations [8,42,48,51], and select the ones that meet our criteria for motion and object complexity. Our selection process involves the following rules:" + }, + { + "type": "text", + "bbox": [ + 0.502, + 0.238, + 0.894, + 0.329 + ], + "angle": 0, + "content": "R1. We only include videos that have multiple objects within the frame in MeViS; videos with only one or two salient objects are not considered. We specifically look for videos that depict many objects with similar appearances, such as the first example video in Figure 1 which shows three yellow parrots." + }, + { + "type": "text", + "bbox": [ + 0.502, + 0.33, + 0.892, + 0.375 + ], + "angle": 0, + "content": "R2. We select videos that contain objects that demonstrate substantial motion and movement. Videos depicting objects that have little or no motion are excluded." + }, + { + "type": "list", + "bbox": [ + 0.502, + 0.238, + 0.894, + 0.375 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.375, + 0.895, + 0.555 + ], + "angle": 0, + "content": "After reviewing over 4,000 potential candidates, we carefully selected the most appropriate and suitable videos that meet our rigorous standards for both visual and linguistic content. Ultimately, by prioritizing quality over quantity, we chose 2,006 videos to create a benchmark that is diverse and representative of a wide range of real-world video scenarios. The basic language annotation methodology and procedure for MeViS follow the ReferIt [20], which is an interactive game-like approach that involves two players taking turns to annotate and validate. The following section will introduce the process of language expression annotation and validation in more detail." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.562, + 0.895, + 0.73 + ], + "angle": 0, + "content": "Language Expression Annotation. We developed a web-based annotation system for annotating language expressions. The system randomly selects a video from the MeViS dataset and displays all object masks of the selected video on the web system. The annotator needs to choose one or several objects from the video and write the corresponding referring expression according to the guidelines for annotating language expressions. To ensure that the language expressions in our dataset align with our focus on motion-based video segmentation, we established several guidelines for annotating the language expressions:" + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.735, + 0.892, + 0.78 + ], + "angle": 0, + "content": "A1. Target objects must exhibit significant motion. Objects that remain stationary or only demonstrate minimal motion should be disregarded." + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.781, + 0.892, + 0.826 + ], + "angle": 0, + "content": "A2. If an object can be unambiguously described by its motion or action, static attributes such as color should not be included in the expression." + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.827, + 0.894, + 0.902 + ], + "angle": 0, + "content": "A3. If multiple objects cannot be differentiated based solely on their motion or action, they can be described together if their motion or action can unambiguously identify them, such as \"The two lions fighting and running amidst a group of lions.\"" + }, + { + "type": "list", + "bbox": [ + 0.501, + 0.735, + 0.894, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.517, + 0.957 + ], + "angle": 0, + "content": "2696" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.089, + 0.892, + 0.131 + ], + "angle": 0, + "content": "Table 1. Statistics of representative language-guided video segmentation datasets. The newly built MeViS has the largest number of objects and language expressions. More importantly, MeViS focuses on segmenting objects in the videos indicated by motion expressions. The MeViS enables the investigation of the feasibility of using motion expressions for object segmentation and grounding in videos." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.133, + 0.89, + 0.267 + ], + "angle": 0, + "content": "
DatasetYearPub.VideoObjectExpressionMaskObject/ VideoObject/ ExperisionTarget
A2D Sentence [13]2018CVPR3,7824,8256,65658k1.281Actor
J-HMDB Sentence [13]2018CVPR92892892831.8k11Actor
DAVIS16-RVOS [21]2018ACCV50501003.4k1n/aObject
DAVIS17-RVOS [21]2018ACCV902051,54413.5k2.271Object
Refer-Youtube-VOS [44]2020ECCV3,9787,45115,009131k1.861Object
MeViS (ours)2023ICCV2,0068,17128,570443k4.281.59Object(s)
" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.278, + 0.471, + 0.325 + ], + "angle": 0, + "content": "A4. If it is not possible to differentiate single or multiple objects based solely on their motion or action, limited static attributes can be included in the expression." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.328, + 0.473, + 0.617 + ], + "angle": 0, + "content": "Language Expression Validation. Upon receiving annotated \"video-object-expression\" samples from the annotators, the validation process begins by displaying the video and expression and prompting the validator to select and submit the objects referred to in the expression. The validator must find the targets independently and submit their selection. The system then compares the targets chosen by the validator with the annotations submitted by the annotator. A sample is considered valid if the validator and annotator independently selected the same target object(s) using the same expression. If the targets selected by the validator do not match the annotation submitted by the annotator, the sample will be forwarded to another validator for a second opinion. If the second validator also fails to identify the correct targets, the sample will be considered invalid and excluded from the dataset. Validator have the authority to reject samples that are deemed inappropriate or fall short of quality standards. Moreover, we stress the importance of the following validation criterion:" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.62, + 0.47, + 0.68 + ], + "angle": 0, + "content": "V1. The corresponding sentence will be removed from the dataset when the target object described by a sentence can be identified through a single frame without the need for motion information." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.686, + 0.47, + 0.777 + ], + "angle": 0, + "content": "By establishing these validation criteria, we aim to ensure that the language sentences in our dataset accurately express motion and are of high quality, while also increasing the level of difficulty in the language-guided video segmentation task, thereby enabling a more robust evaluation of the performance of different models and methods." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.787, + 0.348, + 0.803 + ], + "angle": 0, + "content": "3.2. Dataset Analysis and Statistics" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.81, + 0.471, + 0.901 + ], + "angle": 0, + "content": "In Table 1, we present a statistical analysis of the newly proposed MeViS dataset, using 5 previous referring video object segmentation datasets as references, including A2D Sentence [13], J-HMDB Sentence [13], DAVIS16-RVOS [21], DAVIS17-RVOS [21], and Refer-Youtu-VOS [44]. As shown in Table 1, MeViS contains 2,006" + }, + { + "type": "image", + "bbox": [ + 0.499, + 0.281, + 0.691, + 0.39 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.547, + 0.392, + 0.675, + 0.404 + ], + "angle": 0, + "content": "(a). Durations of videos" + }, + { + "type": "image", + "bbox": [ + 0.697, + 0.284, + 0.886, + 0.39 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.743, + 0.392, + 0.873, + 0.405 + ], + "angle": 0, + "content": "(b). Durations of objects" + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.412, + 0.892, + 0.482 + ], + "angle": 0, + "content": "Figure 2. The duration of videos and objects of MeViS and Refer-Youtu-VOS [44], in seconds. The vertical lines and values in the legends represent the mean duration across the two datasets. The duration of both videos and objects in MeViS is significantly longer than Refer-Youtu-VOS." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.491, + 0.893, + 0.612 + ], + "angle": 0, + "content": "videos and 8,171 objects. Compared to Refer-Youtu-VOS [44], which is based on the existing VOS dataset [56], MeViS has more objects (8,171 vs. 7,451), more expressions (28,570 vs. 15,009), and more annotation masks (443k vs. 131k). In the following, we discuss how the proposed dataset MeViS intentionally increases the complexities of language-guided video segmentation by considering the challenges of both linguistic and visual modalities." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.614, + 0.895, + 0.901 + ], + "angle": 0, + "content": "- Video Content. As shown in Table 1, MeViS has an average of 4.28 objects per video, which is higher than previous datasets. Furthermore, as depicted in Figure 2, MeViS contains longer videos, with an average duration of 13.16 seconds, which is significantly longer than the Refer-Youtu-VOS dataset. These intentional design choices make MeViS more complex and challenging for language-guided video segmentation. This is in contrast to existing datasets such as A2D Sentence [13] and \\(\\mathrm{DAVIS}_{16}\\)-RVOS [21], where only one or two salient objects per category are present, and the model can choose the most prominent object as the target or identify the target object based on the category name. For example, in Figure 3(b), there is only one person in the foreground, and the model can simply identify the target by the term \"a person\" while ignoring \"skateboarding\". The proposed MeViS dataset addresses this limitation by selecting videos with more objects that have diverse and dynamic motions. Moreover, MeViS features many videos with objects of the same" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2697" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.09, + 0.177, + 0.145 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.179, + 0.09, + 0.272, + 0.135 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.275, + 0.09, + 0.37, + 0.135 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.372, + 0.091, + 0.466, + 0.135 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.094, + 0.15, + 0.165, + 0.168 + ], + "angle": 0, + "content": "(a). \"Giraffes turning around\"" + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.2, + 0.177, + 0.245 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.179, + 0.136, + 0.272, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.275, + 0.137, + 0.37, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.372, + 0.137, + 0.466, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.08, + 0.246, + 0.178, + 0.264 + ], + "angle": 0, + "content": "(b). \"A person skating.\"" + }, + { + "type": "image", + "bbox": [ + 0.179, + 0.185, + 0.272, + 0.231 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.275, + 0.185, + 0.37, + 0.231 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.372, + 0.186, + 0.466, + 0.231 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.179, + 0.232, + 0.272, + 0.276 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.275, + 0.232, + 0.369, + 0.276 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.372, + 0.232, + 0.466, + 0.276 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.279, + 0.47, + 0.362 + ], + "angle": 0, + "content": "Figure 3. (a) Example from MeViS. (b) Example from Refer-Youtu-VOS [44]. Compared to Refer-Youtu-VOS: \\(\\bullet\\) Videos in MeViS contain more objects in complex environments, making it impossible to identify the target object via saliency or category information alone. \\(\\bullet\\) The number of target objects indicated by language expression in MeViS is arbitrary, from 1 to many." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.381, + 0.47, + 0.518 + ], + "angle": 0, + "content": "category, such as a group of tigers or rabbits. For instance, in Figure 3(a), there are three giraffes with highly similar appearances, and the most salient foreground one is not the target object in this sample, making it challenging to identify the target object(s) through saliency or category information alone. By including more challenging videos, MeViS better simulates real-world scenarios, making it a valuable resource for studying motion expression-guided video understanding in complex environments." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.522, + 0.471, + 0.826 + ], + "angle": 0, + "content": "Target Object(s). As we have included longer videos in our MeViS dataset, we have also observed a significant increase in the duration of target objects, ensuring adequate object motions. As shown in Figure 2(b), the object durations in our dataset have an average of 10.88 seconds, which is more than two times longer than the average duration of Refer-Youtu-VOS. Compared to previous datasets, such as A2D Sentence [13] and J-HMDB Sentence [13], which focus on salient actions of a few categories [44], our MeViS dataset includes more categories from open-world [8, 42, 48, 51], presenting improved difficulties in the diversity of target objects. Besides, as shown in Table 1, previous datasets usually have one sentence referring to one single object, which means that finding multiple objects requires multiple expressions, and each object must be searched for individually*. In contrast, we add a more natural way of selecting target objects, where one expression may refer to several objects, denoted as \"multi-object expression\". An example of multi-object expression is shown in Figure 3(a), where \"Giraffes that turns around\" refers to two giraffes." + }, + { + "type": "image", + "bbox": [ + 0.507, + 0.09, + 0.882, + 0.234 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.239, + 0.892, + 0.295 + ], + "angle": 0, + "content": "Figure 4. Word cloud of the top 100 words in the MeViS dataset. MeViS has a large number of words that describe motions, like \"walking\", \"moving\", \"playing\", and many position words that are related to motions, such as \"left\", \"right\"." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.309, + 0.892, + 0.355 + ], + "angle": 0, + "content": "As shown in Table 1, on average, each expression in MeViS refers to 1.59 objects, which is larger than existing datasets where the average is only 1 object per expression." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.358, + 0.893, + 0.782 + ], + "angle": 0, + "content": "Language Expression. One of the key distinguishing aspects of the MeViS dataset is its emphasis on describing object motions in language expressions. The previous largest RVOS dataset Refer-Youtu-VOS [44] provides two types of language annotations: full-video expression and first-frame expression. The first-frame expression is based solely on static attributes of the first frame image, whereas the full-video expression considers the entire video. However, in many cases, even the full-video expressions contain static attributes that could potentially enable the target object to be identified in a single frame, for example, \"A person on the right dressed in blue black...\". In contrast, to explore the practicality of employing motion expressions for object localization and segmentation in videos, MeViS is intentionally designed to include a range of diverse and dynamic object motions, making it more challenging to identify the target object based on static attributes alone. In MeViS, there are significantly more motion expressions that explicitly identify the target object based on its distinctive actions or movements. The language expressions in the proposed MeViS contain more motion attributes, such as object position moving through the video and actions that span several frames. The word cloud of the newly proposed MeViS is visualized in Figure 4. From the word cloud figure, we can observe that MeViS dataset has a large number of words that describe motions, like \"walking\", \"moving\", \"playing\", and many relative directions that are related to motions, such as \"left\", \"right\", etc." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.794, + 0.625, + 0.811 + ], + "angle": 0, + "content": "4. Experiment" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.826, + 0.893, + 0.901 + ], + "angle": 0, + "content": "Evaluation Metrics. Similar to previous studies such as [21,44], we employ two widely used metrics, \\(\\mathcal{I}\\) and \\(\\mathcal{F}\\), to assess the performance of methods on the newly proposed MeViS dataset. The region similarity metric \\(\\mathcal{I}\\) computes the Intersection over Union (IoU) of the predicted and" + }, + { + "type": "page_footnote", + "bbox": [ + 0.076, + 0.839, + 0.47, + 0.902 + ], + "angle": 0, + "content": "*Although some datasets like \\( \\mathrm{DAVIS}_{16} \\)-RVOS [21] contain samples of multiple instances as targets, the mask annotations provided by \\( \\mathrm{DAVIS}_{16} \\) [40] do not distinguish instances, and some target masks cover several instances. Thus, each sample in \\( \\mathrm{DAVIS}_{16} \\)-RVOS can be considered as a single-sentence single-object pair." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2698" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.089, + 0.538, + 0.148 + ], + "angle": 0, + "content": "Table 2. Temporal Context (TC) shows varying impacts on 3 datasets. Image-based methods, like VLT [10], can achieve state-of-the-art performance on \\(\\mathrm{DAVIS}_{17}\\)-RVOS [21] and Refer-Youtu-VOS (RYV) [44], but cannot well handle the harder motion challenges in MeViS that require temporal context." + }, + { + "type": "table", + "bbox": [ + 0.093, + 0.153, + 0.526, + 0.23 + ], + "angle": 0, + "content": "
MethodsTypeTemporalDAVIS17-RVOSRYVMeViS
VLT [10]Image1 frame60.463.127.8
RFormer [55]Video5 rand. frames60.262.831.0
VLT+TCVideoAll frames60.362.735.5
RFormer+TCVideoAll frames59.963.036.3
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.242, + 0.471, + 0.318 + ], + "angle": 0, + "content": "ground-truth masks, which reflects the quality of the segmentation. The F-measure \\(\\mathcal{F}\\) reflects the contour accuracy of the prediction. To provide a comprehensive evaluation of the method's overall effectiveness, we calculate the average of these two metrics, denoted as \\(\\mathcal{J} \\& \\mathcal{F}\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.324, + 0.472, + 0.402 + ], + "angle": 0, + "content": "Dataset Setting. The MeViS dataset is a large-scale dataset that consists of a total of 2,006 videos along with 28,570 sentences. These videos are split into three subsets, i.e., training set, validation set, and testing set, which contain 1,712 videos, 140 videos, and 154 videos, respectively." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.41, + 0.371, + 0.426 + ], + "angle": 0, + "content": "4.1. Dataset Necessity and Challenges" + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.433, + 0.473, + 0.903 + ], + "angle": 0, + "content": "To show the necessity and validity of MeViS in motion expression understanding, we compare the results of state-of-the-art referring image segmentation method VLT [10] and referring video segmentation method ReferFormer [55] on \\(\\mathrm{DAVIS}_{17}\\)-RVOS [21], Refer-Youtu-VOS [44], and MeViS, as shown in Table 2. When trained on referring video segmentation dataset, such as Refer-Youtu-VOS [44] and testing on itself, the image-based method VLT [10] that does not use any temporal design can achieve exceptional results of \\(60.4\\%\\) \\(\\mathcal{J} \\& \\mathcal{F}\\) and \\(63.1\\%\\) \\(\\mathcal{J} \\& \\mathcal{F}\\) on video datasets \\(\\mathrm{DAVIS}_{17}\\)-RVOS [21] and Refer-Youtu-VOS [44], respectively, which are even better than video method ReferFormer [55]. The results suggest that for \\(\\mathrm{DAVIS}_{17}\\)-RVOS [21] and Refer-Youtu-VOS [44], the temporal context is not essential, and image-based methods that use static clues can achieve good performance on these two datasets. However, on the proposed MeViS, VLT [10] only achieves a score of \\(27.8\\%\\) \\(\\mathcal{J} \\& \\mathcal{F}\\), suggesting that referring image segmentation methods without temporal designs struggle to address the unique challenges presented by videos in our dataset, particularly in handling motion, despite their success on other benchmark datasets. Furthermore, by comparing the results of VLT [10] with ReferFormer [55], which is trained using five randomly selected frames from the video, we find that ReferFormer outperforms VLT by a large margin of \\(3.2\\%\\) in terms of \\(\\mathcal{J} \\& \\mathcal{F}\\). This further highlights the importance of analyzing long-term motions in the MeViS dataset. In order to further prove this point, we enhance VLT and ReferFormer by incorporating an attention module at the head to perceive and gather global temporal context (\"TC\" in Table 2)." + }, + { + "type": "table_caption", + "bbox": [ + 0.551, + 0.089, + 0.885, + 0.16 + ], + "angle": 0, + "content": "Table 3. Image-video cross-dataset validation. We train the models on referring image segmentation dataset Ref-COCO+/g, and test their performance on three different video datasets. The models trained on images perform worse on MeViS than on the other two datasets." + }, + { + "type": "table", + "bbox": [ + 0.554, + 0.163, + 0.892, + 0.229 + ], + "angle": 0, + "content": "
Training on Referring Image Segmentation Dataset
MethodsTypeDAVIS17-RVOSRYVMeViS
VLT [10]Image54.246.122.5
RFormer [55]Video55.645.227.0
" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.242, + 0.892, + 0.362 + ], + "angle": 0, + "content": "For module details, please refer to \"Motion Perception\" in Section 4.2. Adding temporal context via this module results in both VLT and ReferFormer achieving a performance gain of approximately \\(5\\%\\) \\(\\mathcal{J}\\& \\mathcal{F}\\), underscoring the significance of temporal context for MeViS. However, it is worth noting that longer temporal information does not necessarily lead to better performance on \\(\\mathrm{DAVIS}_{17}\\)-RVOS and Refer-Youtu-VOS." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.364, + 0.893, + 0.607 + ], + "angle": 0, + "content": "We also conduct a cross-dataset experiment by training on referring image segmentation datasets and testing on referring video segmentation datasets. The results in Table 3 show that both the image-based method VLT [10] and video-based method ReferFormer [55] achieve competitive results on Refer-Youtu-VOS [44] and \\(\\mathrm{DAVIS}_{17}\\)-RVOS [21] when trained on image datasets Ref-COCO, Ref-COCO+, and Ref-COCOg. These results suggest that the expressions in Refer-Youtu-VOS [44] and DAVIS17-RVOS [21] provide static clues like in the image domain, and many target objects can be identified by examining a single frame solely. In contrast, when trained on referring image segmentation datasets and tested on MeViS, both VLT [10] and ReferFormer [55] perform worse, indicating that there is a significant expression-gap (e.g., static vs. motion) between MeViS and these image domain datasets." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.62, + 0.825, + 0.636 + ], + "angle": 0, + "content": "4.2. LMPM: A Simple Baseline Approach" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.644, + 0.895, + 0.902 + ], + "angle": 0, + "content": "The MeViS dataset introduces unique challenges in detecting and understanding object motions in both video and language contexts. The motions described by language expressions can occur over a random number of frames, making it necessary to capture fleeting actions and movements that occur throughout the entire video. This presents significant challenges for recognizing motions in the video content and the corresponding language expressions. Detecting fleeting actions requires meticulous perceiving of every frame while comprehending complex and extended motion spanning multiple frames requires contextual understanding across the entire duration of the video. Current state-of-the-art methods, such as [2, 11, 55], rely on random sampling of a few frames, which may miss frames containing crucial information described by the given expression. Furthermore, these methods fail to effectively extract temporal contextual information and" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2699" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.089, + 0.891, + 0.263 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.271, + 0.893, + 0.342 + ], + "angle": 0, + "content": "Figure 5. The overview architecture of the proposed baseline approach Language-guided Motion Perception and Matching (LMPM). We first detect all possible target objects in each frame of the video and use object embeddings to represent them through Language-Guided Extractor. Then, Motion Perception is conducted on all the object embeddings of the video to grasp the global temporal context. By leveraging language queries and object embeddings with motion information, we generate object trajectories through a Transformer Decoder. Finally, we match the language features with the predicted object trajectories to identify the target object(s)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.362, + 0.471, + 0.453 + ], + "angle": 0, + "content": "instead simply use spatial-temporal feature extractors due to the significant burden on computational resources of temporal communication. Additionally, as illustrated in Section 3, objects described by language expressions can vary from one to multiple, requiring the output to cover from one to an arbitrary number of objects." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.463, + 0.471, + 0.901 + ], + "angle": 0, + "content": "To address the challenges posed by the MeViS dataset, we propose a baseline approach called Language-guided Motion Perception and Matching (LMPM), which is depicted in Figure 5. LMPM generates \\( N_{1} \\) language-based queries to identify potential target objects in the video, across \\( T \\) frames, and produces object embeddings to represent each of them. Using language queries instead of conventional object queries can filter out irrelevant objects and ensure the efficiency and effectiveness of subsequent operations [9, 10]. Inspired by VITA [15], we represent objects using object embeddings, which provide instance-specific information, to reduce computational requirements [24, 25]. After obtaining object embeddings from frames in the video, we perform motion perception by inter-frame self-attention on the object embeddings to obtain a global view across \\( T \\) frames. Motion perception enables object embeddings to capture temporal contextual information that spans multiple frames, or even the entire video. Then, we use \\( N_{2} \\) language queries as the query and the object embeddings after Motion Perception as the key and value for the Transformer decoder. The Transformer decoder decodes language-related information from all object embeddings and aggregates relevant information to predict object trajectories. Finally, we match the language features with the predicted object trajectories to identify the target object(s). Rather than only selecting the best-matched object trajectory, we use a matching threshold \\( \\sigma \\) to choose object trajectories only if their similarity with the language features exceeds the threshold \\( \\sigma \\). This enables the model" + }, + { + "type": "table_caption", + "bbox": [ + 0.525, + 0.36, + 0.866, + 0.374 + ], + "angle": 0, + "content": "Table 4. Ablation study of the baseline approach LMPM." + }, + { + "type": "table", + "bbox": [ + 0.508, + 0.377, + 0.887, + 0.444 + ], + "angle": 0, + "content": "
IDLanguage QueryMotion PerceptionMatchingJ&F
i✓××31.0
ii✓✓×36.3
iii✓✓✓37.2
" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.45, + 0.892, + 0.481 + ], + "angle": 0, + "content": "to handle not only single-object expressions but also multi-object expressions, which is a unique feature of MeViS." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.487, + 0.893, + 0.683 + ], + "angle": 0, + "content": "Implementation Details. We set all the hyper-parameters related to the Language-Guided Extractor to the default settings of Mask2Former [4], including the backbone, Transformer decoder. We train 150,000 iterations using AdamW optimizer [35] with a learning rate of 0.00005. Tiny Swin Transformer [33] is employed as our backbone in all the experiments. The input frames are resized to have a minimum size of 448 pixels on the shorter side during inference. Motion Perception consists of six layers, and the Transformer decoder employs three layers. For the hyperparameter settings, we set \\(\\sigma\\), \\(N_{1}\\) and \\(N_{2}\\) to 0.8, 20, and 10, respectively. We use RoBERTa [32] as a text encoder that is consistent with the ReferFormer and is frozen all the time." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.689, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Ablation study of LMPM. In Table 4, we present an ablation study of the baseline approach LMPM. We perform the following three experiments: (i) First, we use language queries to detect potential target object trajectories and output the best trajectory, similar to ReferFormer [55]. This variant achieves a \\(\\mathcal{J}\\& \\mathcal{F}\\) score of \\(31.0\\%\\). It relies solely on language information with 5 randomly sampled frames and neglects global temporal context across the video, making it unable to effectively process long-term motions. (ii) With the help of Motion Perception, the \\(\\mathcal{J}\\& \\mathcal{F}\\) score significantly improves by \\(5.3\\%\\), as it captures temporal contextual information and a global view of the entire video, which are critical for MeViS. (iii) Since MeViS contains multi-objects expressions, outputting only the object with" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2700" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.164, + 0.09, + 0.383, + 0.102 + ], + "angle": 0, + "content": "Table 5. MeViS Benchmark Results." + }, + { + "type": "table", + "bbox": [ + 0.081, + 0.105, + 0.468, + 0.209 + ], + "angle": 0, + "content": "
MethodsJ&FJF
URVOS [44]27.825.729.9
LBDT [11]29.327.830.8
MTTR [2]30.028.831.2
ReferFormer [55]31.029.832.2
VLT+TC [10]35.533.637.3
LMPM (ours)37.234.240.2
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.233, + 0.47, + 0.309 + ], + "angle": 0, + "content": "the highest score is insufficient. We introduce a matching mechanism to identify the target object(s), enabling our method to handle not only single-object expressions but also multi-object expressions. This variant outperforms (ii) by \\(0.9\\%\\) in terms of \\(\\mathcal{J}\\& \\mathcal{F}\\) score." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.322, + 0.321, + 0.336 + ], + "angle": 0, + "content": "4.3. MeViS Benchmark Results" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.344, + 0.47, + 0.678 + ], + "angle": 0, + "content": "Quantitative results. We performed a comprehensive evaluation of the MeViS dataset to assess the performance of existing methods in the more challenging motion-expression scenarios. We evaluated 1 modified image-based method VLT [10] and 4 recent state-of-the-art video-based methods, including URVOS [44], LBDT [11], MTTR [2], and ReferFormer [55], on the validation set\\(^{\\dagger}\\) of MeViS. The evaluation results, presented in Table 5, indicate that the current state-of-the-art methods could only achieve performance ranging from \\(27.8\\%\\) \\(\\mathcal{J}\\& \\mathcal{F}\\) to \\(31.0\\%\\) \\(\\mathcal{J}\\& \\mathcal{F}\\) on the validation set of MeViS, while their results on other benchmarks like Refer-Youtu-VOS [44] and DAVIS\\(_{17}\\)-RVOS [21] are usually above \\(60\\%\\) \\(\\mathcal{J}\\& \\mathcal{F}\\). Our experiments demonstrate that while notable progress has been made in language-guided video object segmentation on existing benchmarks, the challenges presented by MeViS underline the need for further exploration of motion expression-guided video segmentation in complex scenarios. These challenges can arise from various factors, including both linguistic and visual modalities, such as the use of motion expressions and highly dynamic objects or fast-paced motions in videos, which can impact the overall performance of algorithms." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.682, + 0.47, + 0.879 + ], + "angle": 0, + "content": "Visualizations. Figure 6 displays some of the success and failure cases of the baseline approach LMPM. Example (a) and (b) depict successful cases where LMPM effectively processes expressions of long-term motions such as \"moving to the front ...\" and \"goes out of the screen\". In contrast, example (c) and (d) are failure cases. In example (c), the expression involves the target object disappearing and reappearing, which poses a significant challenge for the model's global understanding of the video. In this case, our model becomes disoriented after the target object reappears. Example (d) shows a sentence describing a long-term motion while involving multiple target objects. Our method successfully identifies the multiple targets, i.e., the" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.09, + 0.889, + 0.128 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.532, + 0.129, + 0.854, + 0.138 + ], + "angle": 0, + "content": "(a). \"The monkey moving to the front of another monkey, and turning\"" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.139, + 0.889, + 0.177 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.565, + 0.178, + 0.825, + 0.188 + ], + "angle": 0, + "content": "(b). \"The panda that goes out of the screen towards left\"" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.188, + 0.889, + 0.226 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.565, + 0.227, + 0.825, + 0.237 + ], + "angle": 0, + "content": "(c). \"The dog that disappears from left, then re-appears\"" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.238, + 0.889, + 0.282 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.523, + 0.283, + 0.862, + 0.293 + ], + "angle": 0, + "content": "(d). \"Two goats walking from the distance to the front, then turning back\"" + }, + { + "type": "image_caption", + "bbox": [ + 0.53, + 0.299, + 0.86, + 0.312 + ], + "angle": 0, + "content": "Figure 6. Example success and failure cases of LMPM." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.33, + 0.892, + 0.452 + ], + "angle": 0, + "content": "\"two goats walking from the distance\", at the beginning of the video. However, one of the targets is lost during the later stages of the video when the motions of objects became complex and tangled. These two failure cases demonstrate the complexity and challenges of MeViS, emphasizing the importance of a strong ability to comprehend the global temporal context of the entire video and to understand the motion expression for models working on MeViS." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.467, + 0.747, + 0.482 + ], + "angle": 0, + "content": "5. Conclusion and Discussion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.493, + 0.891, + 0.583 + ], + "angle": 0, + "content": "The ability to effectively understand and leverage motion expressions as a primary cue for object segmentation in videos remains an unresolved challenge that requires attention in future research. The proposed large-scale benchmark MeViS provides a foundation for developing more advanced language-guided video segmentation algorithms." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.584, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Future Directions. There are many interesting research directions and remaining challenges to be addressed with the MeViS dataset. These include but are not limited to: (i) exploring new techniques for better motion understanding and modeling in both visual and linguistic modalities, (ii) designing more elegant and robust models that can effectively handle diverse motion types spanning across a range of frames, including long-term/short-term and complex motions, (iii) developing advanced models that can handle complex scenes with various types of objects and expressions, (iv) creating more efficient models that can effectively reduce the number of redundant detected objects, (v) designing effective cross-modal fusion methods to better leverage the complementary information between language and visual signals, (vi) investigating the potential of transfer learning and domain adaptation in language-guided video segmentation, and (vii) developing methods that can better handle the open-world concepts in both the visual and linguistic domain. These challenges require significant research efforts to advance the state-of-the-art in language-guided video segmentation." + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.461, + 0.901 + ], + "angle": 0, + "content": "The test set is utilized for evaluation during the competition periods." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "2701" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.093, + 0.473, + 0.168 + ], + "angle": 0, + "content": "Acknowledgement. This study is supported under the RIE2020 Industry Alignment Fund - Industry Collaboration Projects (IAF-ICP) Funding Initiative, as well as cash and in-kind contribution from the industry partner(s). This study is also supported by the research grant of NTU Presidential Postdoctoral Fellowship. The data of MeViS is released for non-commercial research purposes only." + }, + { + "type": "title", + "bbox": [ + 0.08, + 0.178, + 0.174, + 0.194 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.203, + 0.47, + 0.251 + ], + "angle": 0, + "content": "[1] Miriam Bellver, Carles Ventura, Carina Silberer, Ioannis Kazakos, Jordi Torres, and Xavier Giro-i Nieto. A closer look at referring expressions for video object segmentation. Multimedia Tools and Applications, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.251, + 0.47, + 0.299 + ], + "angle": 0, + "content": "[2] Adam Botach, Evgenii Zheltonozhskii, and Chaim Baskin. End-to-end referring video object segmentation with multimodal transformers. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 2, 3, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.3, + 0.469, + 0.347 + ], + "angle": 0, + "content": "[3] Weidong Chen, Dexiang Hong, Yuankai Qi, Zhenjun Han, Shuhui Wang, Laiyun Qing, Qingming Huang, and Guorong Li. Multi-attention network for compressed video referring object segmentation. In ACM Int. Conf. Multimedia, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.347, + 0.469, + 0.394 + ], + "angle": 0, + "content": "[4] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.395, + 0.469, + 0.432 + ], + "angle": 0, + "content": "[5] Henghui Ding, Scott Cohen, Brian Price, and Xudong Jiang. PhraseClick: toward achieving flexible interactive segmentation by phrase and click. In Proc. Eur. Conf. Comput. Vis., 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.432, + 0.469, + 0.478 + ], + "angle": 0, + "content": "[6] Henghui Ding, Xudong Jiang, Ai Qun Liu, Nadia Magnenat Thalmann, and Gang Wang. Boundary-aware feature propagation for scene segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.479, + 0.469, + 0.527 + ], + "angle": 0, + "content": "[7] Henghui Ding, Xudong Jiang, Bing Shuai, Ai Qun Liu, and Gang Wang. Context contrasted feature and gated multi-scale aggregation for scene segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.528, + 0.469, + 0.574 + ], + "angle": 0, + "content": "[8] Henghui Ding, Chang Liu, Shuting He, Xudong Jiang, Philip HS Torr, and Song Bai. MOSE: A new dataset for video object segmentation in complex scenes. In Proc. IEEE Int. Conf. Comput. Vis., 2023. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.576, + 0.469, + 0.622 + ], + "angle": 0, + "content": "[9] Henghui Ding, Chang Liu, Suchen Wang, and Xudong Jiang. Vision-language transformer and query generation for referring segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2021. 2, 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.624, + 0.469, + 0.671 + ], + "angle": 0, + "content": "[10] Henghui Ding, Chang Liu, Suchen Wang, and Xudong Jiang. VLT: Vision-language transformer and query generation for referring segmentation. IEEE Trans. Pattern Anal. Mach. Intell., 2023. 2, 3, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.672, + 0.469, + 0.719 + ], + "angle": 0, + "content": "[11] Zihan Ding, Tianrui Hui, Junshi Huang, Xiaoming Wei, Jizhong Han, and Si Liu. Language-bridged spatial-temporal interaction for referring video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 2, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.72, + 0.469, + 0.767 + ], + "angle": 0, + "content": "[12] Guang Feng, Zhiwei Hu, Lihe Zhang, and Huchuan Lu. Encoder fusion network with co-attention embedding for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.768, + 0.469, + 0.804 + ], + "angle": 0, + "content": "[13] Kirill Gavrilyuk, Amir Ghodrati, Zhenyang Li, and Cees GM Snoek. Actor and action video segmentation from a sentence. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 1, 2, 3, 4, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.805, + 0.469, + 0.828 + ], + "angle": 0, + "content": "[14] Kaiming He, Georgia Gkioxari, Piotr Dollar, and Ross Girshick. Mask r-cnn. In Proc. IEEE Int. Conf. Comput. Vis., 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.829, + 0.469, + 0.864 + ], + "angle": 0, + "content": "[15] Miran Heo, Sukjun Hwang, Seoung Wug Oh, Joon-Young Lee, and Seon Joo Kim. Vita: Video instance segmentation via object token association. In Proc. Adv. Neural Inform. Process. Syst., 2022. 2, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.865, + 0.469, + 0.899 + ], + "angle": 0, + "content": "[16] Ronghang Hu, Marcus Rohrbach, and Trevor Darrell. Segmentation from natural language expressions. In Proc. Eur. Conf. Comput. Vis., 2016. 2" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.203, + 0.47, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.094, + 0.892, + 0.142 + ], + "angle": 0, + "content": "[17] Tianrui Hui, Shaofei Huang, Si Liu, Zihan Ding, Guanbin Li, Wenguan Wang, Jizhong Han, and Fei Wang. Collaborative spatial-temporal modeling for language-queried video actor segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.143, + 0.892, + 0.192 + ], + "angle": 0, + "content": "[18] Tianrui Hui, Si Liu, Shaofei Huang, Guanbin Li, Sansi Yu, Faxi Zhang, and Jizhong Han. Linguistic structure guided context modeling for referring image segmentation. In Proc. Eur. Conf. Comput. Vis., 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.193, + 0.892, + 0.24 + ], + "angle": 0, + "content": "[19] Ya Jing, Tao Kong, Wei Wang, Liang Wang, Lei Li, and Tieniu Tan. Locate then segment: A strong pipeline for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.242, + 0.892, + 0.302 + ], + "angle": 0, + "content": "[20] Sahar Kazemzadeh, Vicente Ordonez, Mark Matten, and Tamara Berg. ReferItGame: Referring to objects in photographs of natural scenes. In Proc. of the Conf. on Empirical Methods in Natural Language Process., Doha, Qatar, 2014. Association for Computational Linguistics. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.304, + 0.892, + 0.34 + ], + "angle": 0, + "content": "[21] Anna Khoreva, Anna Rohrbach, and Bernt Schiele. Video object segmentation with language referring expressions. In Proc. Asi. Conf. Comput. Vis., 2018. 1, 2, 3, 4, 5, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.342, + 0.892, + 0.388 + ], + "angle": 0, + "content": "[22] Namyup Kim, Dongwon Kim, Cuiling Lan, Wenjun Zeng, and Suha Kwak. Restr: Convolution-free referring image segmentation using transformers. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.391, + 0.892, + 0.438 + ], + "angle": 0, + "content": "[23] Ruiyu Li, Kaican Li, Yi-Chun Kuo, Michelle Shu, Xiaojuan Qi, Xiaoyong Shen, and Jiaya Jia. Referring image segmentation via recurrent refinement networks. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.44, + 0.892, + 0.489 + ], + "angle": 0, + "content": "[24] Xiangtai Li, Henghui Ding, Wenwei Zhang, Haobo Yuan, Jiangmiao Pang, Guangliang Cheng, Kai Chen, Ziwei Liu, and Chen Change Loy. Transformer-based visual segmentation: A survey. arXiv preprint arXiv:2304.09854, 2023. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.49, + 0.892, + 0.527 + ], + "angle": 0, + "content": "[25] Xiangtai Li, Haobo Yuan, Wenwei Zhang, Guangliang Cheng, Jiangmiao Pang, and Chen Change Loy. Tube-link: A flexible cross tube baseline for universal video segmentation. ICCV, 2023. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.528, + 0.892, + 0.576 + ], + "angle": 0, + "content": "[26] Chen Liang, Yu Wu, Tianfei Zhou, Wenguan Wang, Zongxin Yang, Yunchao Wei, and Yi Yang. Rethinking cross-modal interaction from a top-down perspective for referring video object segmentation. arXiv preprint arXiv:2106.01061, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.577, + 0.892, + 0.613 + ], + "angle": 0, + "content": "[27] Chang Liu, Henghui Ding, and Xudong Jiang. GRES: Generalized referring expression segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.615, + 0.892, + 0.651 + ], + "angle": 0, + "content": "[28] Chang Liu, Henghui Ding, Yulun Zhang, and Xudong Jiang. Multimodal mutual attention and iterative interaction for referring image segmentation. IEEE Trans. Image Processing, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.653, + 0.892, + 0.688 + ], + "angle": 0, + "content": "[29] Chang Liu, Xudong Jiang, and Henghui Ding. Instance-specific feature propagation for referring segmentation. IEEE Trans. Multimedia, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.69, + 0.892, + 0.727 + ], + "angle": 0, + "content": "[30] Chenxi Liu, Zhe Lin, Xiaohui Shen, Jimei Yang, Xin Lu, and Alan Yuille. Recurrent multimodal interaction for referring image segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.728, + 0.892, + 0.764 + ], + "angle": 0, + "content": "[31] Si Liu, Tianrui Hui, Shaofei Huang, Yunchao Wei, Bo Li, and Guanbin Li. Cross-modal progressive comprehension for referring segmentation. IEEE Trans. Pattern Anal. Mach. Intell., 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.765, + 0.892, + 0.813 + ], + "angle": 0, + "content": "[32] Yinhan Liu, Myle Ott, Naman Goyal, Jingfei Du, Mandar Joshi, Danqi Chen, Omer Levy, Mike Lewis, Luke Zettlemoyer, and Veselin Stoyanov. Roberta: A robustly optimized bert pretraining approach. arXiv preprint arXiv:1907.11692, 2019. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.814, + 0.892, + 0.863 + ], + "angle": 0, + "content": "[33] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proc. IEEE Int. Conf. Comput. Vis., 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.864, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[34] Jonathan Long, Evan Shelhamer, and Trevor Darrell. Fully convolutional networks for semantic segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2015. 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.094, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2702" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.094, + 0.468, + 0.118 + ], + "angle": 0, + "content": "[35] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In Proc. Int. Conf. Learn. Represent., 2019. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.12, + 0.469, + 0.167 + ], + "angle": 0, + "content": "[36] Junhua Mao, Jonathan Huang, Alexander Toshev, Oana Camburu, Alan L Yuille, and Kevin Murphy. Generation and comprehension of unambiguous object descriptions. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.169, + 0.469, + 0.216 + ], + "angle": 0, + "content": "[37] Edgar Margffoy-Tuay, Juan C Pérez, Emilio Botero, and Pablo Arbeláez. Dynamic multimodal instance segmentation guided by natural language queries. In Proc. Eur. Conf. Comput. Vis., 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.219, + 0.468, + 0.255 + ], + "angle": 0, + "content": "[38] Bruce McIntosh, Kevin Duarte, Yogesh S Rawat, and Mubarak Shah. Visual-textual capsule routing for text-based video segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.257, + 0.468, + 0.28 + ], + "angle": 0, + "content": "[39] Ke Ning, Lingxi Xie, Fei Wu, and Qi Tian. Polar relative positional encoding for video-language segmentation. In IJCAI, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.282, + 0.468, + 0.341 + ], + "angle": 0, + "content": "[40] Federico Perazzi, Jordi Pont-Tuset, Brian McWilliams, Luc Van Gool, Markus Gross, and Alexander Sorkine-Hornung. A benchmark dataset and evaluation methodology for video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2016. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.344, + 0.468, + 0.39 + ], + "angle": 0, + "content": "[41] Jordi Pont-Tuset, Federico Perazzi, Sergi Caelles, Pablo Arbeláez, Alex Sorkine-Hornung, and Luc Van Gool. The 2017 davis challenge on video object segmentation. arXiv preprint arXiv:1704.00675, 2017.3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.393, + 0.468, + 0.441 + ], + "angle": 0, + "content": "[42] Jiyang Qi, Yan Gao, Yao Hu, Xinggang Wang, Xiaoyu Liu, Xiang Bai, Serge Belongie, Alan Yuille, Philip HS Torr, and Song Bai. Occluded video instance segmentation: A benchmark. Int. J. Comput. Vis., 130(8), 2022. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.443, + 0.468, + 0.502 + ], + "angle": 0, + "content": "[43] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In Proc. Int. Conf. Mach. Learn., 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.504, + 0.468, + 0.551 + ], + "angle": 0, + "content": "[44] Seonguk Seo, Joon-Young Lee, and Bohyung Han. Urvos: Unified referring video object segmentation network with a large-scale benchmark. In Proc. Eur. Conf. Comput. Vis., 2020. 1, 2, 3, 4, 5, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.554, + 0.468, + 0.601 + ], + "angle": 0, + "content": "[45] Mingjie Sun, Jimin Xiao, Eng GEE Lim, and Yao Zhao. Starting point selection and multiple-standard matching for video object segmentation with language annotation. IEEE Trans. Multimedia, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.604, + 0.468, + 0.651 + ], + "angle": 0, + "content": "[46] Zongheng Tang, Yue Liao, Si Liu, Guanbin Li, Xiaojie Jin, Hongxu Jiang, Qian Yu, and Dong Xu. Human-centric spatio-temporal video grounding with visual transformers. IEEE Trans. Circuit Syst. Video Technol., 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.653, + 0.468, + 0.7 + ], + "angle": 0, + "content": "[47] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Proc. Adv. Neural Inform. Process. Syst., 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.703, + 0.468, + 0.739 + ], + "angle": 0, + "content": "[48] Paul Voigtlaender, Lishu Luo, Chun Yuan, Yong Jiang, and Bastian Leibe. Reducing the annotation effort for video object segmentation datasets. In Proc. IEEE Winter Conf. Appl. Comput. Vis., 2021. 3, 5" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.094, + 0.469, + 0.739 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.094, + 0.892, + 0.129 + ], + "angle": 0, + "content": "[49] Hao Wang, Cheng Deng, Fan Ma, and Yi Yang. Context modulated dynamic networks for actor and action video segmentation with language queries. In AAAI, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.131, + 0.892, + 0.178 + ], + "angle": 0, + "content": "[50] Hao Wang, Cheng Deng, Junchi Yan, and Dacheng Tao. Asymmetric cross-guided attention network for actor and action video segmentation from natural language query. In Proc. IEEE Int. Conf. Comput. Vis., 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.18, + 0.892, + 0.215 + ], + "angle": 0, + "content": "[51] Weiyao Wang, Matt Feiszli, Heng Wang, and Du Tran. Unidentified video objects: A benchmark for dense, open-world segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2021. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.217, + 0.892, + 0.263 + ], + "angle": 0, + "content": "[52] Zhaoqing Wang, Yu Lu, Qiang Li, Xunqiang Tao, Yandong Guo, Mingming Gong, and Tongliang Liu. Cris: Clip-driven referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.265, + 0.892, + 0.3 + ], + "angle": 0, + "content": "[53] Chenyun Wu, Zhe Lin, Scott Cohen, Trung Bui, and Subhransu Maji. Phrasecut: Language-based image segmentation in the wild. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.302, + 0.892, + 0.349 + ], + "angle": 0, + "content": "[54] Dongming Wu, Xingping Dong, Ling Shao, and Jianbing Shen. Multi-level representation learning with semantic alignment for referring video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.35, + 0.892, + 0.386 + ], + "angle": 0, + "content": "[55] Jiannan Wu, Yi Jiang, Peize Sun, Zehuan Yuan, and Ping Luo. Language as queries for referring video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 2, 3, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.387, + 0.892, + 0.433 + ], + "angle": 0, + "content": "[56] Ning Xu, Linjie Yang, Yuchen Fan, Dingcheng Yue, Yuchen Liang, Jianchao Yang, and Thomas Huang. Youtube-vos: A large-scale video object segmentation benchmark. arXiv preprint arXiv:1809.03327, 2018.3,4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.435, + 0.892, + 0.482 + ], + "angle": 0, + "content": "[57] Antoine Yang, Antoine Miech, Josef Sivic, Ivan Laptev, and Cordelia Schmid. Tubedetr: Spatio-temporal video grounding with transformers. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.484, + 0.892, + 0.519 + ], + "angle": 0, + "content": "[58] Sibei Yang, Meng Xia, Guanbin Li, Hong-Yu Zhou, and Yizhou Yu. Bottom-up shift and reasoning for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.521, + 0.892, + 0.568 + ], + "angle": 0, + "content": "[59] Zhao Yang, Jiaqi Wang, Yansong Tang, Kai Chen, Hengshuang Zhao, and Philip HS Torr. Levt: Language-aware vision transformer for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.569, + 0.892, + 0.605 + ], + "angle": 0, + "content": "[60] Linwei Ye, Mrigank Rochan, Zhi Liu, and Yang Wang. Cross-modal self-attention network for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.606, + 0.892, + 0.653 + ], + "angle": 0, + "content": "[61] Licheng Yu, Zhe Lin, Xiaohui Shen, Jimei Yang, Xin Lu, Mohit Bansal, and Tamara L Berg. Mattnet: Modular attention network for referring expression comprehension. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.654, + 0.892, + 0.69 + ], + "angle": 0, + "content": "[62] Licheng Yu, Patrick Poirson, Shan Yang, Alexander C Berg, and Tamara L Berg. Modeling context in referring expressions. In Proc. Eur. Conf. Comput. Vis., 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.691, + 0.892, + 0.739 + ], + "angle": 0, + "content": "[63] Wangbo Zhao, Kai Wang, Xiangxiang Chu, Fuzhao Xue, Xinchao Wang, and Yang You. Modeling motion with multi-modal features for text-based video segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.094, + 0.892, + 0.739 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.515, + 0.957 + ], + "angle": 0, + "content": "2703" + } + ] +] \ No newline at end of file diff --git a/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/422d1f87-df33-4f64-91c1-e11c03538001_origin.pdf b/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/422d1f87-df33-4f64-91c1-e11c03538001_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..9cf1010f629093ba4ae752cf9885ea28fdea7114 --- /dev/null +++ b/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/422d1f87-df33-4f64-91c1-e11c03538001_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:7ac243f998b096fc36996399ef38d33a7516ecb951ca4772f07a22e394a3a075 +size 2643077 diff --git a/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/full.md b/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/full.md new file mode 100644 index 0000000000000000000000000000000000000000..1cc63cc947dd8e7868ce0a91f082c364be307248 --- /dev/null +++ b/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/full.md @@ -0,0 +1,326 @@ +# MeViS: A Large-scale Benchmark for Video Segmentation with Motion Expressions + +Henghui Ding† Chang Liu‡ Shuting He‡ Xudong Jiang‡ Chen Change Loy† +†S-Lab, Nanyang Technological University ‡School of EEE, Nanyang Technological University https://henghuiding.github.io/MeViS + +![](images/8d09679b058034e7c0e0a113e87343a66f0de249e878c1c8c4237876547b1a96.jpg) +First Frame + +![](images/798617559adaeed9e11156a0bc1d0ebf23bd7e55266266e22cb679d0b143d42b.jpg) + +![](images/35d7ab30b081707096a3a6658f0c248ff2ed05b8318a05b2e52787f335f5a912.jpg) + +![](images/b18065ea7702eba94aac72070e93798bf12f1f5219e01f24b7f5da406e5433fc.jpg) +"The bird flying away" + +![](images/0fbd6692630e9ffab0caf500676060ee2c357d29eef3877c7a3774ddd4a03093.jpg) + +![](images/bdaca24e959789161093efa2a452b82b80687dc27f93c3f395af9f3de26ea84a.jpg) + +![](images/18af1536fd1197e4b52b4017e26d30db10baea00904a186dbe4211b87fcaa0bd.jpg) + +![](images/ab1c916b16a97d206c32ad50bc1e06da9a514bb6a18ac34916bc2fbf15b4957e.jpg) + +![](images/1eea54912ba18f35c12f6d15a6e6ef3fb92598745b24aa2d5b35366755ff7835.jpg) + +![](images/0d58b3f0c15eb2b7cdf6689717b3a3e4cb42356f1be0ae5b7811b877e8bff5ed.jpg) + +![](images/b5750f9762dae3372c90c5de3da36ceb49a84476d23f92aa36162a2b08574380.jpg) +"The cat playing with the teaser" + +![](images/fd35b3a0614045da8409fcdf658fa00d4b439f766ad766e18685e605af5ba7e2.jpg) + +![](images/e6610a5240b6600d42f4364297f9dd04d96ed38daa5b85868280e1e7dbaff32e.jpg) + +![](images/f63f3863f74d89bf1de6bec7786f03f8f5dfb931139a97bb863850329b380dc1.jpg) + +![](images/e1729cbb70ea858f0ba174a0955f1be7039a0047a1bb623457329507ac3938e3.jpg) +Figure 1. Examples of video clips from Motion expressions Video Segmentation (MeViS) are provided to illustrate the dataset's nature and complexity. The expressions in MeViS primarily focus on motion attributes and the referred target object cannot be identified by examining a single frame solely. For instance, the first example features three parrots with similar appearances, and the target object is identified as "The bird flying away". This object can only be recognized by capturing its motion throughout the video. + +![](images/235574c321e7fdaccfb49d505bf5ccf7c6e260d854e6bf4561ffa0523b3c78e6.jpg) + +![](images/89dca7143cd62cf0546ce0c52c067976c6dc2542643185f6e4405bd1c853694d.jpg) +"Bears that walk forwards from left to right then walk back" + +![](images/3b0a810d47432bb562ae4ddff754a58d9270fc2e7989f7d1c60a9d1f00a96d65.jpg) + +![](images/7655cd3a6691a59c389e1144b3923f33d7325309fce54e86429e38c71e75c9da.jpg) + +![](images/b0033eed38d5dd73f94dc949147ddaedd7ab77de00c1cfda72a55a1250631db6.jpg) + +![](images/73562a20892778198fdd2e2b292d0abe3973ccb818613ea00d76faeb0c43eeeb.jpg) + +# Abstract + +This paper strives for motion expressions guided video segmentation, which focuses on segmenting objects in video content based on a sentence describing the motion of the objects. Existing referring video object datasets typically focus on salient objects and use language expressions that contain excessive static attributes that could potentially enable the target object to be identified in a single frame. These datasets downplay the importance of motion in video content for language-guided video object segmentation. To investigate the feasibility of using motion expressions to ground and segment objects in videos, we propose a large-scale dataset called MeViS, which contains numerous motion expressions to indicate target objects in complex environments. We benchmarked 5 existing referring video object segmentation (RVOS) methods and conducted a comprehensive comparison on the MeViS dataset. The results show that current RVOS methods cannot effectively address motion expression-guided video segmentation. We further analyze the challenges and propose a baseline + +approach for the proposed MeViS dataset. The goal of our benchmark is to provide a platform that enables the development of effective language-guided video segmentation algorithms that leverage motion expressions as a primary cue for object segmentation in complex video scenes. The proposed MeViS dataset has been released at https://henghuiding.github.io/MeViS. + +# 1. Introduction + +Language-guided video segmentation is an emerging field that involves segmenting and tracking target objects using natural language expressions. This field has traditionally been a sub-branch of semi-supervised video object segmentation, where referring expressions are used to describe the target object. Existing referring video object datasets, such as [13,21,44], commonly feature videos with isolated and salient objects that have obvious static features. The corresponding expressions often contain static attributes such as object color, which can be observed in a single frame. As a result, motion properties of videos are often + +given less emphasis, and referring image segmentation methods can be used for referring video segmentation, achieving good results [1, 10, 21, 31]. + +In this paper, we wish to highlight the significance of temporal motion properties of videos and explore the potential of using motion expressions to segment objects in videos. To this end, we propose a new large-scale dataset called Motion expressions Video Segmentation (MeViS) to aid our investigation. The MeViS dataset comprises 2,006 videos with a total of 8,171 objects, and 28,570 motion expressions are provided to refer to these objects. + +We take several steps to ensure that the MeViS dataset places emphasis on the temporal motions of videos. First, we carefully select video content that contains multiple objects that coexist with motion and exclude videos with isolated objects that can be easily described by static attributes. Second, we prioritize language expressions that do not contain static clues, such as category names or object colors, in cases where target objects can be unambiguously described by motion words alone. This is distinct from previous datasets, such as [13, 21, 44], which include obvious static clues in their expressions. Additionally, MeViS differentiates itself from referring image segmentation datasets, such as [20, 36, 53, 62], which do not account for the temporal properties of video content. Moreover, unlike existing referring video object segmentation datasets that focus on single-target expressions, where one expression refers to only one target object, MeViS expands this task to include multi-object expressions that refer to multiple target objects. This feature enables expressions to refer to an unlimited number of target objects, making the proposed MeViS more challenging and reflective of real-world scenarios. + +The proposed MeViS dataset poses notable challenges in capturing and understanding motions in both video and language. The language expressions may describe motion that spans a random number of frames, requiring the capture of fleeting movements and long-term actions that occur throughout the entire video. This poses significant challenges for both understanding motion in the video content and in the accompanying language expressions. Capturing fleeting movements requires attention on each individual frame, while understanding long and complex movements that span across many frames demands temporal context across the entire video. With the proposed dataset, we benchmark 5 existing referring video object segmentation (RVOS) methods [2, 10, 11, 44, 55] and conduct a comprehensive comparison. The experimental results demonstrate that MeViS presents more challenges than existing datasets, and current RVOS methods are unable to effectively address motion expression-guided video segmentation. + +In addition to proposing the MeViS dataset, we present a baseline approach, named Language-guided Motion Perception and Matching (LMPM), to address the challenges + +posed by the dataset. Our approach generates language-conditional queries to detect potential target objects in the video and represents them using object embeddings, which are more robust and computationally efficient than object feature maps [15]. We then perform Motion Perception on the object embeddings to capture the temporal context and obtain a global view of the video, enabling the model to understand both fleeting and long-term motions. Next, we use a Transformer decoder to decode language-related information from the motion-aggregated object embeddings and predict object trajectories. Finally, we perform similarity matching between the language features and the predicted object trajectories to identify the target object(s). + +Our contributions provide a foundation for developing more advanced language-guided video segmentation algorithms that leverage motion expressions as a primary cue for object segmentation and identification in complex video scenes. In particular, we propose a new language-guided video segmentation dataset, MeViS, and conduct comprehensive evaluations of state-of-the-art referring video object segmentation methods on the MeViS dataset, providing a reference for future works. We also develop a simple baseline approach, LMPM, which points to potential solutions to some of the challenges and future research directions. + +# 2. Related Work + +Referring Image Segmentation. Referring image segmentation [5, 9, 10, 27, 28], also known as referring expression segmentation, involves grounding the target object in images based on natural language expressions that describe its properties and generating a corresponding segmentation mask. This task requires both language and image understanding and is one of the most fundamental yet challenging tasks in computer vision. Referring image segmentation was first introduced by Hu et al. [16] in 2016 and has received considerable attention since then. In the preTransformer era, mainstream methods typically employed Fully Convolutional Networks (FCN) [6, 7, 34] and Recurrent Neural Networks (RNN) to extract image features and language features, respectively, and then fused the multimodal features via some specially designed modules [12, 23, 30, 37]. For example, Liu et al. [30] introduced a Recurrent Multimodal Interaction (RMI) module to recurrently fuse the feature of each word into the image features. Li et al. [23] proposed a Recurrent Refinement Network (RRN) that progressively refines the segmentation mask based on pyramid features in FCN. + +In addition to one-stage methods that fuse multi-modal features and conduct segmentation, some methods decouple referring image segmentation into instance segmentation and language-object matching [19, 29, 61]. For instance, Yu et al. use the off-the-shelf instance segmentation model Mask R-CNN [14] to detect all instances first and then + +select the one that best matches the language as output. A holistic understanding of language and vision information is crucial for referring image segmentation, and many works have explored this direction [18, 58, 60]. For instance, Ye et al. introduce a Cross-Modal Self-Attention (CMSA) model [60] to select the most meaningful words in the expression and pixels in the image to achieve better contextual understanding. Recently, the success of Transformer [47] in vision tasks has inspired many studies in referring image segmentation. Ding et al. [9, 10] first introduced Transformer into referring segmentation and proposed a Vision-Language Transformer (VLT). Following Ding et al. [9, 10], more Transformer-based methods have been proposed [22, 52, 59]. For example, Wang et al. [52] employ the Vision-Language Decoder to deal with visual and text tokens extracted by CLIP [43]. Yang et al. [59] focus on multi-modal feature fusion and propose a Language-Aware Vision Transformer (LAVT). + +Referring Video Segmentation. Referring video object segmentation is an emerging area [3, 17, 31, 38, 39, 45, 46, 49, 50, 54, 57, 63] that aims to segment the target object indicated by a given expression across the entire video clip. It was first introduced in 2018 by A2D [13] and DAVIS17-RVOS [21], where A2D [13] seeks to segment actors according to descriptions of their actions in video content, and DAVIS17-RVOS [21] replaces masks with language as the reference for the target object in video object segmentation. Later, Seo et al. [44] built the Refer-YouTube-VOS based on the YouTube-VOS-2019 dataset [56]. These datasets typically provide an expression for a single object, and the expression usually describes the static attributes of the target object, such as its color and shape. + +Existing methods typically treat referring video segmentation as a form of semi-supervised video object segmentation [41] by replacing mask reference with language reference. For instance, Khoreva et al. [21] employ the referring image segmentation method MAttNet [61] to achieve frame-level segmentation and then perform post-processing for temporal consistency. URVOS [44] employs cross-modal attention to perform per-frame segmentation and propagate the mask across clips with a memory attention module. RefVOS [1] independently segments each frame based on the fused features of language and image/frame, without utilizing temporal information. Liang et al. [26] introduces a top-down approach that first detects all object tracklets and then selects the target object by matching between language and tracklet features. Most recently, ReferFormer [55] and MTTR [2] employ Transformer [47] to address referring video object segmentation. + +# 3. MeViS Dataset + +In this section, we introduce the newly built large-scale dataset MeViS by first presenting the video collection and + +annotation process in Section 3.1 and then providing the dataset statistics and analysis in Section 3.2. + +# 3.1. Motion Expression Annotation + +Video Collection. We gather and choose videos from publicly available video segmentation datasets with high-quality mask annotations [8,42,48,51], and select the ones that meet our criteria for motion and object complexity. Our selection process involves the following rules: + +R1. We only include videos that have multiple objects within the frame in MeViS; videos with only one or two salient objects are not considered. We specifically look for videos that depict many objects with similar appearances, such as the first example video in Figure 1 which shows three yellow parrots. +R2. We select videos that contain objects that demonstrate substantial motion and movement. Videos depicting objects that have little or no motion are excluded. + +After reviewing over 4,000 potential candidates, we carefully selected the most appropriate and suitable videos that meet our rigorous standards for both visual and linguistic content. Ultimately, by prioritizing quality over quantity, we chose 2,006 videos to create a benchmark that is diverse and representative of a wide range of real-world video scenarios. The basic language annotation methodology and procedure for MeViS follow the ReferIt [20], which is an interactive game-like approach that involves two players taking turns to annotate and validate. The following section will introduce the process of language expression annotation and validation in more detail. + +Language Expression Annotation. We developed a web-based annotation system for annotating language expressions. The system randomly selects a video from the MeViS dataset and displays all object masks of the selected video on the web system. The annotator needs to choose one or several objects from the video and write the corresponding referring expression according to the guidelines for annotating language expressions. To ensure that the language expressions in our dataset align with our focus on motion-based video segmentation, we established several guidelines for annotating the language expressions: + +A1. Target objects must exhibit significant motion. Objects that remain stationary or only demonstrate minimal motion should be disregarded. +A2. If an object can be unambiguously described by its motion or action, static attributes such as color should not be included in the expression. +A3. If multiple objects cannot be differentiated based solely on their motion or action, they can be described together if their motion or action can unambiguously identify them, such as "The two lions fighting and running amidst a group of lions." + +Table 1. Statistics of representative language-guided video segmentation datasets. The newly built MeViS has the largest number of objects and language expressions. More importantly, MeViS focuses on segmenting objects in the videos indicated by motion expressions. The MeViS enables the investigation of the feasibility of using motion expressions for object segmentation and grounding in videos. + +
DatasetYearPub.VideoObjectExpressionMaskObject/ VideoObject/ ExperisionTarget
A2D Sentence [13]2018CVPR3,7824,8256,65658k1.281Actor
J-HMDB Sentence [13]2018CVPR92892892831.8k11Actor
DAVIS16-RVOS [21]2018ACCV50501003.4k1n/aObject
DAVIS17-RVOS [21]2018ACCV902051,54413.5k2.271Object
Refer-Youtube-VOS [44]2020ECCV3,9787,45115,009131k1.861Object
MeViS (ours)2023ICCV2,0068,17128,570443k4.281.59Object(s)
+ +A4. If it is not possible to differentiate single or multiple objects based solely on their motion or action, limited static attributes can be included in the expression. + +Language Expression Validation. Upon receiving annotated "video-object-expression" samples from the annotators, the validation process begins by displaying the video and expression and prompting the validator to select and submit the objects referred to in the expression. The validator must find the targets independently and submit their selection. The system then compares the targets chosen by the validator with the annotations submitted by the annotator. A sample is considered valid if the validator and annotator independently selected the same target object(s) using the same expression. If the targets selected by the validator do not match the annotation submitted by the annotator, the sample will be forwarded to another validator for a second opinion. If the second validator also fails to identify the correct targets, the sample will be considered invalid and excluded from the dataset. Validator have the authority to reject samples that are deemed inappropriate or fall short of quality standards. Moreover, we stress the importance of the following validation criterion: + +V1. The corresponding sentence will be removed from the dataset when the target object described by a sentence can be identified through a single frame without the need for motion information. + +By establishing these validation criteria, we aim to ensure that the language sentences in our dataset accurately express motion and are of high quality, while also increasing the level of difficulty in the language-guided video segmentation task, thereby enabling a more robust evaluation of the performance of different models and methods. + +# 3.2. Dataset Analysis and Statistics + +In Table 1, we present a statistical analysis of the newly proposed MeViS dataset, using 5 previous referring video object segmentation datasets as references, including A2D Sentence [13], J-HMDB Sentence [13], DAVIS16-RVOS [21], DAVIS17-RVOS [21], and Refer-Youtu-VOS [44]. As shown in Table 1, MeViS contains 2,006 + +![](images/91e79fe0ba098408afe6c3ce645eb1c40f1cb0de82c58f7f0f5de053e295826e.jpg) +(a). Durations of videos + +![](images/3bcf24c16111896ff871da85d13aa868af05898d64d0d73c95b5eef6a69e266e.jpg) +(b). Durations of objects +Figure 2. The duration of videos and objects of MeViS and Refer-Youtu-VOS [44], in seconds. The vertical lines and values in the legends represent the mean duration across the two datasets. The duration of both videos and objects in MeViS is significantly longer than Refer-Youtu-VOS. + +videos and 8,171 objects. Compared to Refer-Youtu-VOS [44], which is based on the existing VOS dataset [56], MeViS has more objects (8,171 vs. 7,451), more expressions (28,570 vs. 15,009), and more annotation masks (443k vs. 131k). In the following, we discuss how the proposed dataset MeViS intentionally increases the complexities of language-guided video segmentation by considering the challenges of both linguistic and visual modalities. + +- Video Content. As shown in Table 1, MeViS has an average of 4.28 objects per video, which is higher than previous datasets. Furthermore, as depicted in Figure 2, MeViS contains longer videos, with an average duration of 13.16 seconds, which is significantly longer than the Refer-Youtu-VOS dataset. These intentional design choices make MeViS more complex and challenging for language-guided video segmentation. This is in contrast to existing datasets such as A2D Sentence [13] and $\mathrm{DAVIS}_{16}$ -RVOS [21], where only one or two salient objects per category are present, and the model can choose the most prominent object as the target or identify the target object based on the category name. For example, in Figure 3(b), there is only one person in the foreground, and the model can simply identify the target by the term "a person" while ignoring "skateboarding". The proposed MeViS dataset addresses this limitation by selecting videos with more objects that have diverse and dynamic motions. Moreover, MeViS features many videos with objects of the same + +![](images/0a1a18c9b085aeeee3868d49011958feb59058ac745b980f1d4914ba89b5a405.jpg) +(a). "Giraffes turning around" + +![](images/348d7f1eef02cebc8db282378e3a12159249290159050ee553109d1016fa7148.jpg) + +![](images/b6f6203cc699a86e138e2fe71378d0dde537384ce1d35e5b977d5202600c9913.jpg) + +![](images/ca17754a7f92310e0e97932cbabd6b1e9f8d7132d7082bd3214b0dff0f9b8425.jpg) + +![](images/261bd9855e5d96bf79a1eb6c252cc4d0ae0c69a6cd6b3fb5b2344b1629eabeeb.jpg) +(b). "A person skating." + +![](images/f3b8980f8d7e10d8ff32851925089019a1d7608343c81c03f65c9d179db4efda.jpg) + +![](images/2ec54f5790388ed9254cd9fb1848553b4497c339c8fabf556eda75c28bded610.jpg) + +![](images/9c3c32a99fd22281b498cbf3ee65231f7c32d91408abb16fc479b7076b9ab860.jpg) + +![](images/10ebd9dda2a8f987720960a73ae5cacb16ac3c80f72ad539c995cb75e6a98e14.jpg) + +![](images/ce2af727ab62078d03844def69a37e0789c17e7dbbd030349423e33e658a3b60.jpg) + +![](images/2ccd32f87cc5d8e2f5506bfe3f07567ad948a59a77ad3e0f76f5b4a4182698e4.jpg) + +![](images/ef8f1e1c43e5f891870fbef2cb9d0c2e0f17a16290589157696f9e22fae02136.jpg) +Figure 3. (a) Example from MeViS. (b) Example from Refer-Youtu-VOS [44]. Compared to Refer-Youtu-VOS: $\bullet$ Videos in MeViS contain more objects in complex environments, making it impossible to identify the target object via saliency or category information alone. $\bullet$ The number of target objects indicated by language expression in MeViS is arbitrary, from 1 to many. + +![](images/5b8e39569cd5fc3da8741927284d6d3611a7e4f594c36557d09743fbc948810d.jpg) + +![](images/80ee0ed1a600bacc2a803002840d59b20092e215e0db57c8c308499c84c16d39.jpg) + +category, such as a group of tigers or rabbits. For instance, in Figure 3(a), there are three giraffes with highly similar appearances, and the most salient foreground one is not the target object in this sample, making it challenging to identify the target object(s) through saliency or category information alone. By including more challenging videos, MeViS better simulates real-world scenarios, making it a valuable resource for studying motion expression-guided video understanding in complex environments. + +Target Object(s). As we have included longer videos in our MeViS dataset, we have also observed a significant increase in the duration of target objects, ensuring adequate object motions. As shown in Figure 2(b), the object durations in our dataset have an average of 10.88 seconds, which is more than two times longer than the average duration of Refer-Youtu-VOS. Compared to previous datasets, such as A2D Sentence [13] and J-HMDB Sentence [13], which focus on salient actions of a few categories [44], our MeViS dataset includes more categories from open-world [8, 42, 48, 51], presenting improved difficulties in the diversity of target objects. Besides, as shown in Table 1, previous datasets usually have one sentence referring to one single object, which means that finding multiple objects requires multiple expressions, and each object must be searched for individually*. In contrast, we add a more natural way of selecting target objects, where one expression may refer to several objects, denoted as "multi-object expression". An example of multi-object expression is shown in Figure 3(a), where "Giraffes that turns around" refers to two giraffes. + +![](images/993fc699d1e1017ad8a285d37aa82df0cda92bccd4744b4f2c46c290fc8ea6c0.jpg) +Figure 4. Word cloud of the top 100 words in the MeViS dataset. MeViS has a large number of words that describe motions, like "walking", "moving", "playing", and many position words that are related to motions, such as "left", "right". + +As shown in Table 1, on average, each expression in MeViS refers to 1.59 objects, which is larger than existing datasets where the average is only 1 object per expression. + +Language Expression. One of the key distinguishing aspects of the MeViS dataset is its emphasis on describing object motions in language expressions. The previous largest RVOS dataset Refer-Youtu-VOS [44] provides two types of language annotations: full-video expression and first-frame expression. The first-frame expression is based solely on static attributes of the first frame image, whereas the full-video expression considers the entire video. However, in many cases, even the full-video expressions contain static attributes that could potentially enable the target object to be identified in a single frame, for example, "A person on the right dressed in blue black...". In contrast, to explore the practicality of employing motion expressions for object localization and segmentation in videos, MeViS is intentionally designed to include a range of diverse and dynamic object motions, making it more challenging to identify the target object based on static attributes alone. In MeViS, there are significantly more motion expressions that explicitly identify the target object based on its distinctive actions or movements. The language expressions in the proposed MeViS contain more motion attributes, such as object position moving through the video and actions that span several frames. The word cloud of the newly proposed MeViS is visualized in Figure 4. From the word cloud figure, we can observe that MeViS dataset has a large number of words that describe motions, like "walking", "moving", "playing", and many relative directions that are related to motions, such as "left", "right", etc. + +# 4. Experiment + +Evaluation Metrics. Similar to previous studies such as [21,44], we employ two widely used metrics, $\mathcal{I}$ and $\mathcal{F}$ , to assess the performance of methods on the newly proposed MeViS dataset. The region similarity metric $\mathcal{I}$ computes the Intersection over Union (IoU) of the predicted and + +Table 2. Temporal Context (TC) shows varying impacts on 3 datasets. Image-based methods, like VLT [10], can achieve state-of-the-art performance on $\mathrm{DAVIS}_{17}$ -RVOS [21] and Refer-Youtu-VOS (RYV) [44], but cannot well handle the harder motion challenges in MeViS that require temporal context. + +
MethodsTypeTemporalDAVIS17-RVOSRYVMeViS
VLT [10]Image1 frame60.463.127.8
RFormer [55]Video5 rand. frames60.262.831.0
VLT+TCVideoAll frames60.362.735.5
RFormer+TCVideoAll frames59.963.036.3
+ +ground-truth masks, which reflects the quality of the segmentation. The F-measure $\mathcal{F}$ reflects the contour accuracy of the prediction. To provide a comprehensive evaluation of the method's overall effectiveness, we calculate the average of these two metrics, denoted as $\mathcal{J} \& \mathcal{F}$ . + +Dataset Setting. The MeViS dataset is a large-scale dataset that consists of a total of 2,006 videos along with 28,570 sentences. These videos are split into three subsets, i.e., training set, validation set, and testing set, which contain 1,712 videos, 140 videos, and 154 videos, respectively. + +# 4.1. Dataset Necessity and Challenges + +To show the necessity and validity of MeViS in motion expression understanding, we compare the results of state-of-the-art referring image segmentation method VLT [10] and referring video segmentation method ReferFormer [55] on $\mathrm{DAVIS}_{17}$ -RVOS [21], Refer-Youtu-VOS [44], and MeViS, as shown in Table 2. When trained on referring video segmentation dataset, such as Refer-Youtu-VOS [44] and testing on itself, the image-based method VLT [10] that does not use any temporal design can achieve exceptional results of $60.4\%$ $\mathcal{J} \& \mathcal{F}$ and $63.1\%$ $\mathcal{J} \& \mathcal{F}$ on video datasets $\mathrm{DAVIS}_{17}$ -RVOS [21] and Refer-Youtu-VOS [44], respectively, which are even better than video method ReferFormer [55]. The results suggest that for $\mathrm{DAVIS}_{17}$ -RVOS [21] and Refer-Youtu-VOS [44], the temporal context is not essential, and image-based methods that use static clues can achieve good performance on these two datasets. However, on the proposed MeViS, VLT [10] only achieves a score of $27.8\%$ $\mathcal{J} \& \mathcal{F}$ , suggesting that referring image segmentation methods without temporal designs struggle to address the unique challenges presented by videos in our dataset, particularly in handling motion, despite their success on other benchmark datasets. Furthermore, by comparing the results of VLT [10] with ReferFormer [55], which is trained using five randomly selected frames from the video, we find that ReferFormer outperforms VLT by a large margin of $3.2\%$ in terms of $\mathcal{J} \& \mathcal{F}$ . This further highlights the importance of analyzing long-term motions in the MeViS dataset. In order to further prove this point, we enhance VLT and ReferFormer by incorporating an attention module at the head to perceive and gather global temporal context ("TC" in Table 2). + +Table 3. Image-video cross-dataset validation. We train the models on referring image segmentation dataset Ref-COCO+/g, and test their performance on three different video datasets. The models trained on images perform worse on MeViS than on the other two datasets. + +
Training on Referring Image Segmentation Dataset
MethodsTypeDAVIS17-RVOSRYVMeViS
VLT [10]Image54.246.122.5
RFormer [55]Video55.645.227.0
+ +For module details, please refer to "Motion Perception" in Section 4.2. Adding temporal context via this module results in both VLT and ReferFormer achieving a performance gain of approximately $5\%$ $\mathcal{J}\& \mathcal{F}$ , underscoring the significance of temporal context for MeViS. However, it is worth noting that longer temporal information does not necessarily lead to better performance on $\mathrm{DAVIS}_{17}$ -RVOS and Refer-Youtu-VOS. + +We also conduct a cross-dataset experiment by training on referring image segmentation datasets and testing on referring video segmentation datasets. The results in Table 3 show that both the image-based method VLT [10] and video-based method ReferFormer [55] achieve competitive results on Refer-Youtu-VOS [44] and $\mathrm{DAVIS}_{17}$ -RVOS [21] when trained on image datasets Ref-COCO, Ref-COCO+, and Ref-COCOg. These results suggest that the expressions in Refer-Youtu-VOS [44] and DAVIS17-RVOS [21] provide static clues like in the image domain, and many target objects can be identified by examining a single frame solely. In contrast, when trained on referring image segmentation datasets and tested on MeViS, both VLT [10] and ReferFormer [55] perform worse, indicating that there is a significant expression-gap (e.g., static vs. motion) between MeViS and these image domain datasets. + +# 4.2. LMPM: A Simple Baseline Approach + +The MeViS dataset introduces unique challenges in detecting and understanding object motions in both video and language contexts. The motions described by language expressions can occur over a random number of frames, making it necessary to capture fleeting actions and movements that occur throughout the entire video. This presents significant challenges for recognizing motions in the video content and the corresponding language expressions. Detecting fleeting actions requires meticulous perceiving of every frame while comprehending complex and extended motion spanning multiple frames requires contextual understanding across the entire duration of the video. Current state-of-the-art methods, such as [2, 11, 55], rely on random sampling of a few frames, which may miss frames containing crucial information described by the given expression. Furthermore, these methods fail to effectively extract temporal contextual information and + +![](images/35c8dce7a0cdc952b19d53eaa1f125064dc2e8f988110c7388fed37fbc8f0a43.jpg) +Figure 5. The overview architecture of the proposed baseline approach Language-guided Motion Perception and Matching (LMPM). We first detect all possible target objects in each frame of the video and use object embeddings to represent them through Language-Guided Extractor. Then, Motion Perception is conducted on all the object embeddings of the video to grasp the global temporal context. By leveraging language queries and object embeddings with motion information, we generate object trajectories through a Transformer Decoder. Finally, we match the language features with the predicted object trajectories to identify the target object(s). + +instead simply use spatial-temporal feature extractors due to the significant burden on computational resources of temporal communication. Additionally, as illustrated in Section 3, objects described by language expressions can vary from one to multiple, requiring the output to cover from one to an arbitrary number of objects. + +To address the challenges posed by the MeViS dataset, we propose a baseline approach called Language-guided Motion Perception and Matching (LMPM), which is depicted in Figure 5. LMPM generates $N_{1}$ language-based queries to identify potential target objects in the video, across $T$ frames, and produces object embeddings to represent each of them. Using language queries instead of conventional object queries can filter out irrelevant objects and ensure the efficiency and effectiveness of subsequent operations [9, 10]. Inspired by VITA [15], we represent objects using object embeddings, which provide instance-specific information, to reduce computational requirements [24, 25]. After obtaining object embeddings from frames in the video, we perform motion perception by inter-frame self-attention on the object embeddings to obtain a global view across $T$ frames. Motion perception enables object embeddings to capture temporal contextual information that spans multiple frames, or even the entire video. Then, we use $N_{2}$ language queries as the query and the object embeddings after Motion Perception as the key and value for the Transformer decoder. The Transformer decoder decodes language-related information from all object embeddings and aggregates relevant information to predict object trajectories. Finally, we match the language features with the predicted object trajectories to identify the target object(s). Rather than only selecting the best-matched object trajectory, we use a matching threshold $\sigma$ to choose object trajectories only if their similarity with the language features exceeds the threshold $\sigma$ . This enables the model + +Table 4. Ablation study of the baseline approach LMPM. + +
IDLanguage QueryMotion PerceptionMatchingJ&F
i✓××31.0
ii✓✓×36.3
iii✓✓✓37.2
+ +to handle not only single-object expressions but also multi-object expressions, which is a unique feature of MeViS. + +Implementation Details. We set all the hyper-parameters related to the Language-Guided Extractor to the default settings of Mask2Former [4], including the backbone, Transformer decoder. We train 150,000 iterations using AdamW optimizer [35] with a learning rate of 0.00005. Tiny Swin Transformer [33] is employed as our backbone in all the experiments. The input frames are resized to have a minimum size of 448 pixels on the shorter side during inference. Motion Perception consists of six layers, and the Transformer decoder employs three layers. For the hyperparameter settings, we set $\sigma$ , $N_{1}$ and $N_{2}$ to 0.8, 20, and 10, respectively. We use RoBERTa [32] as a text encoder that is consistent with the ReferFormer and is frozen all the time. + +Ablation study of LMPM. In Table 4, we present an ablation study of the baseline approach LMPM. We perform the following three experiments: (i) First, we use language queries to detect potential target object trajectories and output the best trajectory, similar to ReferFormer [55]. This variant achieves a $\mathcal{J}\& \mathcal{F}$ score of $31.0\%$ . It relies solely on language information with 5 randomly sampled frames and neglects global temporal context across the video, making it unable to effectively process long-term motions. (ii) With the help of Motion Perception, the $\mathcal{J}\& \mathcal{F}$ score significantly improves by $5.3\%$ , as it captures temporal contextual information and a global view of the entire video, which are critical for MeViS. (iii) Since MeViS contains multi-objects expressions, outputting only the object with + +Table 5. MeViS Benchmark Results. + +
MethodsJ&FJF
URVOS [44]27.825.729.9
LBDT [11]29.327.830.8
MTTR [2]30.028.831.2
ReferFormer [55]31.029.832.2
VLT+TC [10]35.533.637.3
LMPM (ours)37.234.240.2
+ +the highest score is insufficient. We introduce a matching mechanism to identify the target object(s), enabling our method to handle not only single-object expressions but also multi-object expressions. This variant outperforms (ii) by $0.9\%$ in terms of $\mathcal{J}\& \mathcal{F}$ score. + +# 4.3. MeViS Benchmark Results + +Quantitative results. We performed a comprehensive evaluation of the MeViS dataset to assess the performance of existing methods in the more challenging motion-expression scenarios. We evaluated 1 modified image-based method VLT [10] and 4 recent state-of-the-art video-based methods, including URVOS [44], LBDT [11], MTTR [2], and ReferFormer [55], on the validation set $^{\dagger}$ of MeViS. The evaluation results, presented in Table 5, indicate that the current state-of-the-art methods could only achieve performance ranging from $27.8\%$ $\mathcal{J}\& \mathcal{F}$ to $31.0\%$ $\mathcal{J}\& \mathcal{F}$ on the validation set of MeViS, while their results on other benchmarks like Refer-Youtu-VOS [44] and DAVIS $_{17}$ -RVOS [21] are usually above $60\%$ $\mathcal{J}\& \mathcal{F}$ . Our experiments demonstrate that while notable progress has been made in language-guided video object segmentation on existing benchmarks, the challenges presented by MeViS underline the need for further exploration of motion expression-guided video segmentation in complex scenarios. These challenges can arise from various factors, including both linguistic and visual modalities, such as the use of motion expressions and highly dynamic objects or fast-paced motions in videos, which can impact the overall performance of algorithms. + +Visualizations. Figure 6 displays some of the success and failure cases of the baseline approach LMPM. Example (a) and (b) depict successful cases where LMPM effectively processes expressions of long-term motions such as "moving to the front ..." and "goes out of the screen". In contrast, example (c) and (d) are failure cases. In example (c), the expression involves the target object disappearing and reappearing, which poses a significant challenge for the model's global understanding of the video. In this case, our model becomes disoriented after the target object reappears. Example (d) shows a sentence describing a long-term motion while involving multiple target objects. Our method successfully identifies the multiple targets, i.e., the + +![](images/58f8e788fb86e04d6894ac76c8076d5a0567f8c85605d33759136bd191c7405c.jpg) +(a). "The monkey moving to the front of another monkey, and turning" + +![](images/320ef5dd75b619d0406fa231e31187eaf0c3e7c116dd517032f9a2495cfeaf00.jpg) +(b). "The panda that goes out of the screen towards left" + +![](images/9f67730a70d4fea923e3c87690148a83ca422782ec79a7dad0c269fbd1d7e920.jpg) +(c). "The dog that disappears from left, then re-appears" + +![](images/a053ab9b8e2b4ffb8a78a07c8e622f5877b5cf822b8c5cf67dc2c2832c9846e4.jpg) +(d). "Two goats walking from the distance to the front, then turning back" +Figure 6. Example success and failure cases of LMPM. + +"two goats walking from the distance", at the beginning of the video. However, one of the targets is lost during the later stages of the video when the motions of objects became complex and tangled. These two failure cases demonstrate the complexity and challenges of MeViS, emphasizing the importance of a strong ability to comprehend the global temporal context of the entire video and to understand the motion expression for models working on MeViS. + +# 5. Conclusion and Discussion + +The ability to effectively understand and leverage motion expressions as a primary cue for object segmentation in videos remains an unresolved challenge that requires attention in future research. The proposed large-scale benchmark MeViS provides a foundation for developing more advanced language-guided video segmentation algorithms. + +Future Directions. There are many interesting research directions and remaining challenges to be addressed with the MeViS dataset. These include but are not limited to: (i) exploring new techniques for better motion understanding and modeling in both visual and linguistic modalities, (ii) designing more elegant and robust models that can effectively handle diverse motion types spanning across a range of frames, including long-term/short-term and complex motions, (iii) developing advanced models that can handle complex scenes with various types of objects and expressions, (iv) creating more efficient models that can effectively reduce the number of redundant detected objects, (v) designing effective cross-modal fusion methods to better leverage the complementary information between language and visual signals, (vi) investigating the potential of transfer learning and domain adaptation in language-guided video segmentation, and (vii) developing methods that can better handle the open-world concepts in both the visual and linguistic domain. These challenges require significant research efforts to advance the state-of-the-art in language-guided video segmentation. + +Acknowledgement. This study is supported under the RIE2020 Industry Alignment Fund - Industry Collaboration Projects (IAF-ICP) Funding Initiative, as well as cash and in-kind contribution from the industry partner(s). This study is also supported by the research grant of NTU Presidential Postdoctoral Fellowship. The data of MeViS is released for non-commercial research purposes only. + +# References + +[1] Miriam Bellver, Carles Ventura, Carina Silberer, Ioannis Kazakos, Jordi Torres, and Xavier Giro-i Nieto. A closer look at referring expressions for video object segmentation. Multimedia Tools and Applications, 2022. 2, 3 +[2] Adam Botach, Evgenii Zheltonozhskii, and Chaim Baskin. End-to-end referring video object segmentation with multimodal transformers. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 2, 3, 6, 8 +[3] Weidong Chen, Dexiang Hong, Yuankai Qi, Zhenjun Han, Shuhui Wang, Laiyun Qing, Qingming Huang, and Guorong Li. Multi-attention network for compressed video referring object segmentation. In ACM Int. Conf. Multimedia, 2022. 3 +[4] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 7 +[5] Henghui Ding, Scott Cohen, Brian Price, and Xudong Jiang. PhraseClick: toward achieving flexible interactive segmentation by phrase and click. In Proc. Eur. Conf. Comput. Vis., 2020. 2 +[6] Henghui Ding, Xudong Jiang, Ai Qun Liu, Nadia Magnenat Thalmann, and Gang Wang. Boundary-aware feature propagation for scene segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2019. 2 +[7] Henghui Ding, Xudong Jiang, Bing Shuai, Ai Qun Liu, and Gang Wang. Context contrasted feature and gated multi-scale aggregation for scene segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 2 +[8] Henghui Ding, Chang Liu, Shuting He, Xudong Jiang, Philip HS Torr, and Song Bai. MOSE: A new dataset for video object segmentation in complex scenes. In Proc. IEEE Int. Conf. Comput. Vis., 2023. 3, 5 +[9] Henghui Ding, Chang Liu, Suchen Wang, and Xudong Jiang. Vision-language transformer and query generation for referring segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2021. 2, 3, 7 +[10] Henghui Ding, Chang Liu, Suchen Wang, and Xudong Jiang. VLT: Vision-language transformer and query generation for referring segmentation. IEEE Trans. Pattern Anal. Mach. Intell., 2023. 2, 3, 6, 7, 8 +[11] Zihan Ding, Tianrui Hui, Junshi Huang, Xiaoming Wei, Jizhong Han, and Si Liu. Language-bridged spatial-temporal interaction for referring video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 2, 6, 8 +[12] Guang Feng, Zhiwei Hu, Lihe Zhang, and Huchuan Lu. Encoder fusion network with co-attention embedding for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 2 +[13] Kirill Gavrilyuk, Amir Ghodrati, Zhenyang Li, and Cees GM Snoek. Actor and action video segmentation from a sentence. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 1, 2, 3, 4, 5 +[14] Kaiming He, Georgia Gkioxari, Piotr Dollar, and Ross Girshick. Mask r-cnn. In Proc. IEEE Int. Conf. Comput. Vis., 2017. 2 +[15] Miran Heo, Sukjun Hwang, Seoung Wug Oh, Joon-Young Lee, and Seon Joo Kim. Vita: Video instance segmentation via object token association. In Proc. Adv. Neural Inform. Process. Syst., 2022. 2, 7 +[16] Ronghang Hu, Marcus Rohrbach, and Trevor Darrell. Segmentation from natural language expressions. In Proc. Eur. Conf. Comput. Vis., 2016. 2 + +[17] Tianrui Hui, Shaofei Huang, Si Liu, Zihan Ding, Guanbin Li, Wenguan Wang, Jizhong Han, and Fei Wang. Collaborative spatial-temporal modeling for language-queried video actor segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 3 +[18] Tianrui Hui, Si Liu, Shaofei Huang, Guanbin Li, Sansi Yu, Faxi Zhang, and Jizhong Han. Linguistic structure guided context modeling for referring image segmentation. In Proc. Eur. Conf. Comput. Vis., 2020. 3 +[19] Ya Jing, Tao Kong, Wei Wang, Liang Wang, Lei Li, and Tieniu Tan. Locate then segment: A strong pipeline for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 2 +[20] Sahar Kazemzadeh, Vicente Ordonez, Mark Matten, and Tamara Berg. ReferItGame: Referring to objects in photographs of natural scenes. In Proc. of the Conf. on Empirical Methods in Natural Language Process., Doha, Qatar, 2014. Association for Computational Linguistics. 2, 3 +[21] Anna Khoreva, Anna Rohrbach, and Bernt Schiele. Video object segmentation with language referring expressions. In Proc. Asi. Conf. Comput. Vis., 2018. 1, 2, 3, 4, 5, 6, 8 +[22] Namyup Kim, Dongwon Kim, Cuiling Lan, Wenjun Zeng, and Suha Kwak. Restr: Convolution-free referring image segmentation using transformers. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3 +[23] Ruiyu Li, Kaican Li, Yi-Chun Kuo, Michelle Shu, Xiaojuan Qi, Xiaoyong Shen, and Jiaya Jia. Referring image segmentation via recurrent refinement networks. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 2 +[24] Xiangtai Li, Henghui Ding, Wenwei Zhang, Haobo Yuan, Jiangmiao Pang, Guangliang Cheng, Kai Chen, Ziwei Liu, and Chen Change Loy. Transformer-based visual segmentation: A survey. arXiv preprint arXiv:2304.09854, 2023. 7 +[25] Xiangtai Li, Haobo Yuan, Wenwei Zhang, Guangliang Cheng, Jiangmiao Pang, and Chen Change Loy. Tube-link: A flexible cross tube baseline for universal video segmentation. ICCV, 2023. 7 +[26] Chen Liang, Yu Wu, Tianfei Zhou, Wenguan Wang, Zongxin Yang, Yunchao Wei, and Yi Yang. Rethinking cross-modal interaction from a top-down perspective for referring video object segmentation. arXiv preprint arXiv:2106.01061, 2021. 3 +[27] Chang Liu, Henghui Ding, and Xudong Jiang. GRES: Generalized referring expression segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2023. 2 +[28] Chang Liu, Henghui Ding, Yulun Zhang, and Xudong Jiang. Multimodal mutual attention and iterative interaction for referring image segmentation. IEEE Trans. Image Processing, 2023. 2 +[29] Chang Liu, Xudong Jiang, and Henghui Ding. Instance-specific feature propagation for referring segmentation. IEEE Trans. Multimedia, 2022. 2 +[30] Chenxi Liu, Zhe Lin, Xiaohui Shen, Jimei Yang, Xin Lu, and Alan Yuille. Recurrent multimodal interaction for referring image segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2017. 2 +[31] Si Liu, Tianrui Hui, Shaofei Huang, Yunchao Wei, Bo Li, and Guanbin Li. Cross-modal progressive comprehension for referring segmentation. IEEE Trans. Pattern Anal. Mach. Intell., 2021. 2, 3 +[32] Yinhan Liu, Myle Ott, Naman Goyal, Jingfei Du, Mandar Joshi, Danqi Chen, Omer Levy, Mike Lewis, Luke Zettlemoyer, and Veselin Stoyanov. Roberta: A robustly optimized bert pretraining approach. arXiv preprint arXiv:1907.11692, 2019. 7 +[33] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proc. IEEE Int. Conf. Comput. Vis., 2021. 7 +[34] Jonathan Long, Evan Shelhamer, and Trevor Darrell. Fully convolutional networks for semantic segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2015. 2 + +[35] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In Proc. Int. Conf. Learn. Represent., 2019. 7 +[36] Junhua Mao, Jonathan Huang, Alexander Toshev, Oana Camburu, Alan L Yuille, and Kevin Murphy. Generation and comprehension of unambiguous object descriptions. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2016. 2 +[37] Edgar Margffoy-Tuay, Juan C Pérez, Emilio Botero, and Pablo Arbeláez. Dynamic multimodal instance segmentation guided by natural language queries. In Proc. Eur. Conf. Comput. Vis., 2018. 2 +[38] Bruce McIntosh, Kevin Duarte, Yogesh S Rawat, and Mubarak Shah. Visual-textual capsule routing for text-based video segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2020. 3 +[39] Ke Ning, Lingxi Xie, Fei Wu, and Qi Tian. Polar relative positional encoding for video-language segmentation. In IJCAI, 2020. 3 +[40] Federico Perazzi, Jordi Pont-Tuset, Brian McWilliams, Luc Van Gool, Markus Gross, and Alexander Sorkine-Hornung. A benchmark dataset and evaluation methodology for video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2016. 5 +[41] Jordi Pont-Tuset, Federico Perazzi, Sergi Caelles, Pablo Arbeláez, Alex Sorkine-Hornung, and Luc Van Gool. The 2017 davis challenge on video object segmentation. arXiv preprint arXiv:1704.00675, 2017.3 +[42] Jiyang Qi, Yan Gao, Yao Hu, Xinggang Wang, Xiaoyu Liu, Xiang Bai, Serge Belongie, Alan Yuille, Philip HS Torr, and Song Bai. Occluded video instance segmentation: A benchmark. Int. J. Comput. Vis., 130(8), 2022. 3, 5 +[43] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In Proc. Int. Conf. Mach. Learn., 2021. 3 +[44] Seonguk Seo, Joon-Young Lee, and Bohyung Han. Urvos: Unified referring video object segmentation network with a large-scale benchmark. In Proc. Eur. Conf. Comput. Vis., 2020. 1, 2, 3, 4, 5, 6, 8 +[45] Mingjie Sun, Jimin Xiao, Eng GEE Lim, and Yao Zhao. Starting point selection and multiple-standard matching for video object segmentation with language annotation. IEEE Trans. Multimedia, 2022. 3 +[46] Zongheng Tang, Yue Liao, Si Liu, Guanbin Li, Xiaojie Jin, Hongxu Jiang, Qian Yu, and Dong Xu. Human-centric spatio-temporal video grounding with visual transformers. IEEE Trans. Circuit Syst. Video Technol., 2021. 3 +[47] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Proc. Adv. Neural Inform. Process. Syst., 2017. 3 +[48] Paul Voigtlaender, Lishu Luo, Chun Yuan, Yong Jiang, and Bastian Leibe. Reducing the annotation effort for video object segmentation datasets. In Proc. IEEE Winter Conf. Appl. Comput. Vis., 2021. 3, 5 + +[49] Hao Wang, Cheng Deng, Fan Ma, and Yi Yang. Context modulated dynamic networks for actor and action video segmentation with language queries. In AAAI, 2020. 3 +[50] Hao Wang, Cheng Deng, Junchi Yan, and Dacheng Tao. Asymmetric cross-guided attention network for actor and action video segmentation from natural language query. In Proc. IEEE Int. Conf. Comput. Vis., 2019. 3 +[51] Weiyao Wang, Matt Feiszli, Heng Wang, and Du Tran. Unidentified video objects: A benchmark for dense, open-world segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2021. 3, 5 +[52] Zhaoqing Wang, Yu Lu, Qiang Li, Xunqiang Tao, Yandong Guo, Mingming Gong, and Tongliang Liu. Cris: Clip-driven referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3 +[53] Chenyun Wu, Zhe Lin, Scott Cohen, Trung Bui, and Subhransu Maji. Phrasecut: Language-based image segmentation in the wild. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2020. 2 +[54] Dongming Wu, Xingping Dong, Ling Shao, and Jianbing Shen. Multi-level representation learning with semantic alignment for referring video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3 +[55] Jiannan Wu, Yi Jiang, Peize Sun, Zehuan Yuan, and Ping Luo. Language as queries for referring video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 2, 3, 6, 7, 8 +[56] Ning Xu, Linjie Yang, Yuchen Fan, Dingcheng Yue, Yuchen Liang, Jianchao Yang, and Thomas Huang. Youtube-vos: A large-scale video object segmentation benchmark. arXiv preprint arXiv:1809.03327, 2018.3,4 +[57] Antoine Yang, Antoine Miech, Josef Sivic, Ivan Laptev, and Cordelia Schmid. Tubedetr: Spatio-temporal video grounding with transformers. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3 +[58] Sibei Yang, Meng Xia, Guanbin Li, Hong-Yu Zhou, and Yizhou Yu. Bottom-up shift and reasoning for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 3 +[59] Zhao Yang, Jiaqi Wang, Yansong Tang, Kai Chen, Hengshuang Zhao, and Philip HS Torr. Levt: Language-aware vision transformer for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3 +[60] Linwei Ye, Mrigank Rochan, Zhi Liu, and Yang Wang. Cross-modal self-attention network for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2019. 3 +[61] Licheng Yu, Zhe Lin, Xiaohui Shen, Jimei Yang, Xin Lu, Mohit Bansal, and Tamara L Berg. Mattnet: Modular attention network for referring expression comprehension. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 2, 3 +[62] Licheng Yu, Patrick Poirson, Shan Yang, Alexander C Berg, and Tamara L Berg. Modeling context in referring expressions. In Proc. Eur. Conf. Comput. Vis., 2016. 2 +[63] Wangbo Zhao, Kai Wang, Xiangxiang Chu, Fuzhao Xue, Xinchao Wang, and Yang You. Modeling motion with multi-modal features for text-based video segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3 \ No newline at end of file diff --git a/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/images.zip b/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..b55f0e43a385038417bac43e7199a240fbcebd7b --- /dev/null +++ b/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:156cf10ab2f3346fecd72c917076af6ad6112a09df03e30975cbb726aa7ea9e0 +size 501659 diff --git a/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/layout.json b/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..16d0fe2260391a25a9152970f3a7ff32c834f9c6 --- /dev/null +++ b/2023/MeViS_ A Large-scale Benchmark for Video Segmentation with Motion Expressions/layout.json @@ -0,0 +1,8905 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 116, + 103, + 477, + 139 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 116, + 103, + 477, + 139 + ], + "spans": [ + { + "bbox": [ + 116, + 103, + 477, + 139 + ], + "type": "text", + "content": "MeViS: A Large-scale Benchmark for Video Segmentation with Motion Expressions" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 61, + 160, + 532, + 204 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 160, + 532, + 204 + ], + "spans": [ + { + "bbox": [ + 61, + 160, + 532, + 204 + ], + "type": "text", + "content": "Henghui Ding† Chang Liu‡ Shuting He‡ Xudong Jiang‡ Chen Change Loy† \n†S-Lab, Nanyang Technological University ‡School of EEE, Nanyang Technological University https://henghuiding.github.io/MeViS" + } + ] + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 50, + 239, + 120, + 279 + ], + "blocks": [ + { + "bbox": [ + 64, + 230, + 105, + 239 + ], + "lines": [ + { + "bbox": [ + 64, + 230, + 105, + 239 + ], + "spans": [ + { + "bbox": [ + 64, + 230, + 105, + 239 + ], + "type": "text", + "content": "First Frame" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 50, + 239, + 120, + 279 + ], + "lines": [ + { + "bbox": [ + 50, + 239, + 120, + 279 + ], + "spans": [ + { + "bbox": [ + 50, + 239, + 120, + 279 + ], + "type": "image", + "image_path": "8d09679b058034e7c0e0a113e87343a66f0de249e878c1c8c4237876547b1a96.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 122, + 239, + 192, + 279 + ], + "blocks": [ + { + "bbox": [ + 122, + 239, + 192, + 279 + ], + "lines": [ + { + "bbox": [ + 122, + 239, + 192, + 279 + ], + "spans": [ + { + "bbox": [ + 122, + 239, + 192, + 279 + ], + "type": "image", + "image_path": "798617559adaeed9e11156a0bc1d0ebf23bd7e55266266e22cb679d0b143d42b.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 193, + 239, + 262, + 279 + ], + "blocks": [ + { + "bbox": [ + 193, + 239, + 262, + 279 + ], + "lines": [ + { + "bbox": [ + 193, + 239, + 262, + 279 + ], + "spans": [ + { + "bbox": [ + 193, + 239, + 262, + 279 + ], + "type": "image", + "image_path": "35d7ab30b081707096a3a6658f0c248ff2ed05b8318a05b2e52787f335f5a912.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 262, + 239, + 332, + 279 + ], + "blocks": [ + { + "bbox": [ + 290, + 228, + 370, + 239 + ], + "lines": [ + { + "bbox": [ + 290, + 228, + 370, + 239 + ], + "spans": [ + { + "bbox": [ + 290, + 228, + 370, + 239 + ], + "type": "text", + "content": "\"The bird flying away\"" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 262, + 239, + 332, + 279 + ], + "lines": [ + { + "bbox": [ + 262, + 239, + 332, + 279 + ], + "spans": [ + { + "bbox": [ + 262, + 239, + 332, + 279 + ], + "type": "image", + "image_path": "b18065ea7702eba94aac72070e93798bf12f1f5219e01f24b7f5da406e5433fc.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 332, + 239, + 402, + 279 + ], + "blocks": [ + { + "bbox": [ + 332, + 239, + 402, + 279 + ], + "lines": [ + { + "bbox": [ + 332, + 239, + 402, + 279 + ], + "spans": [ + { + "bbox": [ + 332, + 239, + 402, + 279 + ], + "type": "image", + "image_path": "0fbd6692630e9ffab0caf500676060ee2c357d29eef3877c7a3774ddd4a03093.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 402, + 239, + 472, + 279 + ], + "blocks": [ + { + "bbox": [ + 402, + 239, + 472, + 279 + ], + "lines": [ + { + "bbox": [ + 402, + 239, + 472, + 279 + ], + "spans": [ + { + "bbox": [ + 402, + 239, + 472, + 279 + ], + "type": "image", + "image_path": "bdaca24e959789161093efa2a452b82b80687dc27f93c3f395af9f3de26ea84a.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 473, + 239, + 543, + 279 + ], + "blocks": [ + { + "bbox": [ + 473, + 239, + 543, + 279 + ], + "lines": [ + { + "bbox": [ + 473, + 239, + 543, + 279 + ], + "spans": [ + { + "bbox": [ + 473, + 239, + 543, + 279 + ], + "type": "image", + "image_path": "18af1536fd1197e4b52b4017e26d30db10baea00904a186dbe4211b87fcaa0bd.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 50, + 292, + 119, + 332 + ], + "blocks": [ + { + "bbox": [ + 50, + 292, + 119, + 332 + ], + "lines": [ + { + "bbox": [ + 50, + 292, + 119, + 332 + ], + "spans": [ + { + "bbox": [ + 50, + 292, + 119, + 332 + ], + "type": "image", + "image_path": "ab1c916b16a97d206c32ad50bc1e06da9a514bb6a18ac34916bc2fbf15b4957e.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 122, + 292, + 192, + 332 + ], + "blocks": [ + { + "bbox": [ + 122, + 292, + 192, + 332 + ], + "lines": [ + { + "bbox": [ + 122, + 292, + 192, + 332 + ], + "spans": [ + { + "bbox": [ + 122, + 292, + 192, + 332 + ], + "type": "image", + "image_path": "1eea54912ba18f35c12f6d15a6e6ef3fb92598745b24aa2d5b35366755ff7835.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 193, + 292, + 262, + 331 + ], + "blocks": [ + { + "bbox": [ + 193, + 292, + 262, + 331 + ], + "lines": [ + { + "bbox": [ + 193, + 292, + 262, + 331 + ], + "spans": [ + { + "bbox": [ + 193, + 292, + 262, + 331 + ], + "type": "image", + "image_path": "0d58b3f0c15eb2b7cdf6689717b3a3e4cb42356f1be0ae5b7811b877e8bff5ed.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 263, + 292, + 332, + 331 + ], + "blocks": [ + { + "bbox": [ + 276, + 281, + 391, + 293 + ], + "lines": [ + { + "bbox": [ + 276, + 281, + 391, + 293 + ], + "spans": [ + { + "bbox": [ + 276, + 281, + 391, + 293 + ], + "type": "text", + "content": "\"The cat playing with the teaser\"" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 263, + 292, + 332, + 331 + ], + "lines": [ + { + "bbox": [ + 263, + 292, + 332, + 331 + ], + "spans": [ + { + "bbox": [ + 263, + 292, + 332, + 331 + ], + "type": "image", + "image_path": "b5750f9762dae3372c90c5de3da36ceb49a84476d23f92aa36162a2b08574380.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 332, + 292, + 402, + 331 + ], + "blocks": [ + { + "bbox": [ + 332, + 292, + 402, + 331 + ], + "lines": [ + { + "bbox": [ + 332, + 292, + 402, + 331 + ], + "spans": [ + { + "bbox": [ + 332, + 292, + 402, + 331 + ], + "type": "image", + "image_path": "fd35b3a0614045da8409fcdf658fa00d4b439f766ad766e18685e605af5ba7e2.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 402, + 292, + 472, + 331 + ], + "blocks": [ + { + "bbox": [ + 402, + 292, + 472, + 331 + ], + "lines": [ + { + "bbox": [ + 402, + 292, + 472, + 331 + ], + "spans": [ + { + "bbox": [ + 402, + 292, + 472, + 331 + ], + "type": "image", + "image_path": "e6610a5240b6600d42f4364297f9dd04d96ed38daa5b85868280e1e7dbaff32e.jpg" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_body" + } + ], + "index": 19 + }, + { + "type": "image", + "bbox": [ + 473, + 292, + 543, + 332 + ], + "blocks": [ + { + "bbox": [ + 473, + 292, + 543, + 332 + ], + "lines": [ + { + "bbox": [ + 473, + 292, + 543, + 332 + ], + "spans": [ + { + "bbox": [ + 473, + 292, + 543, + 332 + ], + "type": "image", + "image_path": "f63f3863f74d89bf1de6bec7786f03f8f5dfb931139a97bb863850329b380dc1.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + } + ], + "index": 20 + }, + { + "type": "image", + "bbox": [ + 49, + 345, + 120, + 384 + ], + "blocks": [ + { + "bbox": [ + 49, + 345, + 120, + 384 + ], + "lines": [ + { + "bbox": [ + 49, + 345, + 120, + 384 + ], + "spans": [ + { + "bbox": [ + 49, + 345, + 120, + 384 + ], + "type": "image", + "image_path": "e1729cbb70ea858f0ba174a0955f1be7039a0047a1bb623457329507ac3938e3.jpg" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 389, + 546, + 434 + ], + "lines": [ + { + "bbox": [ + 46, + 389, + 546, + 434 + ], + "spans": [ + { + "bbox": [ + 46, + 389, + 546, + 434 + ], + "type": "text", + "content": "Figure 1. Examples of video clips from Motion expressions Video Segmentation (MeViS) are provided to illustrate the dataset's nature and complexity. The expressions in MeViS primarily focus on motion attributes and the referred target object cannot be identified by examining a single frame solely. For instance, the first example features three parrots with similar appearances, and the target object is identified as \"The bird flying away\". This object can only be recognized by capturing its motion throughout the video." + } + ] + } + ], + "index": 29, + "angle": 0, + "type": "image_caption" + } + ], + "index": 22 + }, + { + "type": "image", + "bbox": [ + 123, + 345, + 192, + 384 + ], + "blocks": [ + { + "bbox": [ + 123, + 345, + 192, + 384 + ], + "lines": [ + { + "bbox": [ + 123, + 345, + 192, + 384 + ], + "spans": [ + { + "bbox": [ + 123, + 345, + 192, + 384 + ], + "type": "image", + "image_path": "235574c321e7fdaccfb49d505bf5ccf7c6e260d854e6bf4561ffa0523b3c78e6.jpg" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_body" + } + ], + "index": 23 + }, + { + "type": "image", + "bbox": [ + 193, + 345, + 262, + 384 + ], + "blocks": [ + { + "bbox": [ + 229, + 335, + 437, + 345 + ], + "lines": [ + { + "bbox": [ + 229, + 335, + 437, + 345 + ], + "spans": [ + { + "bbox": [ + 229, + 335, + 437, + 345 + ], + "type": "text", + "content": "\"Bears that walk forwards from left to right then walk back\"" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 193, + 345, + 262, + 384 + ], + "lines": [ + { + "bbox": [ + 193, + 345, + 262, + 384 + ], + "spans": [ + { + "bbox": [ + 193, + 345, + 262, + 384 + ], + "type": "image", + "image_path": "89dca7143cd62cf0546ce0c52c067976c6dc2542643185f6e4405bd1c853694d.jpg" + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_body" + } + ], + "index": 24 + }, + { + "type": "image", + "bbox": [ + 262, + 345, + 332, + 384 + ], + "blocks": [ + { + "bbox": [ + 262, + 345, + 332, + 384 + ], + "lines": [ + { + "bbox": [ + 262, + 345, + 332, + 384 + ], + "spans": [ + { + "bbox": [ + 262, + 345, + 332, + 384 + ], + "type": "image", + "image_path": "3b0a810d47432bb562ae4ddff754a58d9270fc2e7989f7d1c60a9d1f00a96d65.jpg" + } + ] + } + ], + "index": 25, + "angle": 0, + "type": "image_body" + } + ], + "index": 25 + }, + { + "type": "image", + "bbox": [ + 332, + 345, + 402, + 384 + ], + "blocks": [ + { + "bbox": [ + 332, + 345, + 402, + 384 + ], + "lines": [ + { + "bbox": [ + 332, + 345, + 402, + 384 + ], + "spans": [ + { + "bbox": [ + 332, + 345, + 402, + 384 + ], + "type": "image", + "image_path": "7655cd3a6691a59c389e1144b3923f33d7325309fce54e86429e38c71e75c9da.jpg" + } + ] + } + ], + "index": 26, + "angle": 0, + "type": "image_body" + } + ], + "index": 26 + }, + { + "type": "image", + "bbox": [ + 402, + 345, + 472, + 384 + ], + "blocks": [ + { + "bbox": [ + 402, + 345, + 472, + 384 + ], + "lines": [ + { + "bbox": [ + 402, + 345, + 472, + 384 + ], + "spans": [ + { + "bbox": [ + 402, + 345, + 472, + 384 + ], + "type": "image", + "image_path": "b0033eed38d5dd73f94dc949147ddaedd7ab77de00c1cfda72a55a1250631db6.jpg" + } + ] + } + ], + "index": 27, + "angle": 0, + "type": "image_body" + } + ], + "index": 27 + }, + { + "type": "image", + "bbox": [ + 473, + 345, + 543, + 384 + ], + "blocks": [ + { + "bbox": [ + 473, + 345, + 543, + 384 + ], + "lines": [ + { + "bbox": [ + 473, + 345, + 543, + 384 + ], + "spans": [ + { + "bbox": [ + 473, + 345, + 543, + 384 + ], + "type": "image", + "image_path": "73562a20892778198fdd2e2b292d0abe3973ccb818613ea00d76faeb0c43eeeb.jpg" + } + ] + } + ], + "index": 28, + "angle": 0, + "type": "image_body" + } + ], + "index": 28 + }, + { + "bbox": [ + 143, + 448, + 192, + 460 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 448, + 192, + 460 + ], + "spans": [ + { + "bbox": [ + 143, + 448, + 192, + 460 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 45, + 468, + 288, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 468, + 288, + 696 + ], + "spans": [ + { + "bbox": [ + 45, + 468, + 288, + 696 + ], + "type": "text", + "content": "This paper strives for motion expressions guided video segmentation, which focuses on segmenting objects in video content based on a sentence describing the motion of the objects. Existing referring video object datasets typically focus on salient objects and use language expressions that contain excessive static attributes that could potentially enable the target object to be identified in a single frame. These datasets downplay the importance of motion in video content for language-guided video object segmentation. To investigate the feasibility of using motion expressions to ground and segment objects in videos, we propose a large-scale dataset called MeViS, which contains numerous motion expressions to indicate target objects in complex environments. We benchmarked 5 existing referring video object segmentation (RVOS) methods and conducted a comprehensive comparison on the MeViS dataset. The results show that current RVOS methods cannot effectively address motion expression-guided video segmentation. We further analyze the challenges and propose a baseline" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 306, + 449, + 547, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 449, + 547, + 533 + ], + "spans": [ + { + "bbox": [ + 306, + 449, + 547, + 533 + ], + "type": "text", + "content": "approach for the proposed MeViS dataset. The goal of our benchmark is to provide a platform that enables the development of effective language-guided video segmentation algorithms that leverage motion expressions as a primary cue for object segmentation in complex video scenes. The proposed MeViS dataset has been released at https://henghuiding.github.io/MeViS." + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 307, + 560, + 387, + 572 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 560, + 387, + 572 + ], + "spans": [ + { + "bbox": [ + 307, + 560, + 387, + 572 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 304, + 582, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 547, + 713 + ], + "type": "text", + "content": "Language-guided video segmentation is an emerging field that involves segmenting and tracking target objects using natural language expressions. This field has traditionally been a sub-branch of semi-supervised video object segmentation, where referring expressions are used to describe the target object. Existing referring video object datasets, such as [13,21,44], commonly feature videos with isolated and salient objects that have obvious static features. The corresponding expressions often contain static attributes such as object color, which can be observed in a single frame. As a result, motion properties of videos are often" + } + ] + } + ], + "index": 34 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 61, + 703, + 219, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 703, + 219, + 713 + ], + "spans": [ + { + "bbox": [ + 61, + 703, + 219, + 713 + ], + "type": "text", + "content": "henghui.ding@gmail.com, ccloy@ntu.edu.sg" + } + ] + } + ], + "index": 35 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2694" + } + ] + } + ], + "index": 36 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 285, + 108 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 285, + 108 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 285, + 108 + ], + "type": "text", + "content": "given less emphasis, and referring image segmentation methods can be used for referring video segmentation, achieving good results [1, 10, 21, 31]." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 110, + 285, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 110, + 285, + 205 + ], + "spans": [ + { + "bbox": [ + 48, + 110, + 285, + 205 + ], + "type": "text", + "content": "In this paper, we wish to highlight the significance of temporal motion properties of videos and explore the potential of using motion expressions to segment objects in videos. To this end, we propose a new large-scale dataset called Motion expressions Video Segmentation (MeViS) to aid our investigation. The MeViS dataset comprises 2,006 videos with a total of 8,171 objects, and 28,570 motion expressions are provided to refer to these objects." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 207, + 285, + 458 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 207, + 285, + 458 + ], + "spans": [ + { + "bbox": [ + 48, + 207, + 285, + 458 + ], + "type": "text", + "content": "We take several steps to ensure that the MeViS dataset places emphasis on the temporal motions of videos. First, we carefully select video content that contains multiple objects that coexist with motion and exclude videos with isolated objects that can be easily described by static attributes. Second, we prioritize language expressions that do not contain static clues, such as category names or object colors, in cases where target objects can be unambiguously described by motion words alone. This is distinct from previous datasets, such as [13, 21, 44], which include obvious static clues in their expressions. Additionally, MeViS differentiates itself from referring image segmentation datasets, such as [20, 36, 53, 62], which do not account for the temporal properties of video content. Moreover, unlike existing referring video object segmentation datasets that focus on single-target expressions, where one expression refers to only one target object, MeViS expands this task to include multi-object expressions that refer to multiple target objects. This feature enables expressions to refer to an unlimited number of target objects, making the proposed MeViS more challenging and reflective of real-world scenarios." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 460, + 285, + 675 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 460, + 285, + 675 + ], + "spans": [ + { + "bbox": [ + 48, + 460, + 285, + 675 + ], + "type": "text", + "content": "The proposed MeViS dataset poses notable challenges in capturing and understanding motions in both video and language. The language expressions may describe motion that spans a random number of frames, requiring the capture of fleeting movements and long-term actions that occur throughout the entire video. This poses significant challenges for both understanding motion in the video content and in the accompanying language expressions. Capturing fleeting movements requires attention on each individual frame, while understanding long and complex movements that span across many frames demands temporal context across the entire video. With the proposed dataset, we benchmark 5 existing referring video object segmentation (RVOS) methods [2, 10, 11, 44, 55] and conduct a comprehensive comparison. The experimental results demonstrate that MeViS presents more challenges than existing datasets, and current RVOS methods are unable to effectively address motion expression-guided video segmentation." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 677, + 285, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 677, + 285, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 677, + 285, + 712 + ], + "type": "text", + "content": "In addition to proposing the MeViS dataset, we present a baseline approach, named Language-guided Motion Perception and Matching (LMPM), to address the challenges" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 308, + 72, + 544, + 227 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 72, + 544, + 227 + ], + "spans": [ + { + "bbox": [ + 308, + 72, + 544, + 227 + ], + "type": "text", + "content": "posed by the dataset. Our approach generates language-conditional queries to detect potential target objects in the video and represents them using object embeddings, which are more robust and computationally efficient than object feature maps [15]. We then perform Motion Perception on the object embeddings to capture the temporal context and obtain a global view of the video, enabling the model to understand both fleeting and long-term motions. Next, we use a Transformer decoder to decode language-related information from the motion-aggregated object embeddings and predict object trajectories. Finally, we perform similarity matching between the language features and the predicted object trajectories to identify the target object(s)." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 308, + 228, + 544, + 358 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 228, + 544, + 358 + ], + "spans": [ + { + "bbox": [ + 308, + 228, + 544, + 358 + ], + "type": "text", + "content": "Our contributions provide a foundation for developing more advanced language-guided video segmentation algorithms that leverage motion expressions as a primary cue for object segmentation and identification in complex video scenes. In particular, we propose a new language-guided video segmentation dataset, MeViS, and conduct comprehensive evaluations of state-of-the-art referring video object segmentation methods on the MeViS dataset, providing a reference for future works. We also develop a simple baseline approach, LMPM, which points to potential solutions to some of the challenges and future research directions." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 308, + 370, + 391, + 383 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 370, + 391, + 383 + ], + "spans": [ + { + "bbox": [ + 308, + 370, + 391, + 383 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 308, + 390, + 544, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 390, + 544, + 640 + ], + "spans": [ + { + "bbox": [ + 308, + 390, + 544, + 640 + ], + "type": "text", + "content": "Referring Image Segmentation. Referring image segmentation [5, 9, 10, 27, 28], also known as referring expression segmentation, involves grounding the target object in images based on natural language expressions that describe its properties and generating a corresponding segmentation mask. This task requires both language and image understanding and is one of the most fundamental yet challenging tasks in computer vision. Referring image segmentation was first introduced by Hu et al. [16] in 2016 and has received considerable attention since then. In the preTransformer era, mainstream methods typically employed Fully Convolutional Networks (FCN) [6, 7, 34] and Recurrent Neural Networks (RNN) to extract image features and language features, respectively, and then fused the multimodal features via some specially designed modules [12, 23, 30, 37]. For example, Liu et al. [30] introduced a Recurrent Multimodal Interaction (RMI) module to recurrently fuse the feature of each word into the image features. Li et al. [23] proposed a Recurrent Refinement Network (RRN) that progressively refines the segmentation mask based on pyramid features in FCN." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 308, + 642, + 544, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 642, + 544, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 642, + 544, + 712 + ], + "type": "text", + "content": "In addition to one-stage methods that fuse multi-modal features and conduct segmentation, some methods decouple referring image segmentation into instance segmentation and language-object matching [19, 29, 61]. For instance, Yu et al. use the off-the-shelf instance segmentation model Mask R-CNN [14] to detect all instances first and then" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 750, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 750, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 750, + 314, + 757 + ], + "type": "text", + "content": "2695" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 286 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 286 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 286 + ], + "type": "text", + "content": "select the one that best matches the language as output. A holistic understanding of language and vision information is crucial for referring image segmentation, and many works have explored this direction [18, 58, 60]. For instance, Ye et al. introduce a Cross-Modal Self-Attention (CMSA) model [60] to select the most meaningful words in the expression and pixels in the image to achieve better contextual understanding. Recently, the success of Transformer [47] in vision tasks has inspired many studies in referring image segmentation. Ding et al. [9, 10] first introduced Transformer into referring segmentation and proposed a Vision-Language Transformer (VLT). Following Ding et al. [9, 10], more Transformer-based methods have been proposed [22, 52, 59]. For example, Wang et al. [52] employ the Vision-Language Decoder to deal with visual and text tokens extracted by CLIP [43]. Yang et al. [59] focus on multi-modal feature fusion and propose a Language-Aware Vision Transformer (LAVT)." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 288, + 289, + 455 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 288, + 289, + 455 + ], + "spans": [ + { + "bbox": [ + 47, + 288, + 289, + 455 + ], + "type": "text", + "content": "Referring Video Segmentation. Referring video object segmentation is an emerging area [3, 17, 31, 38, 39, 45, 46, 49, 50, 54, 57, 63] that aims to segment the target object indicated by a given expression across the entire video clip. It was first introduced in 2018 by A2D [13] and DAVIS17-RVOS [21], where A2D [13] seeks to segment actors according to descriptions of their actions in video content, and DAVIS17-RVOS [21] replaces masks with language as the reference for the target object in video object segmentation. Later, Seo et al. [44] built the Refer-YouTube-VOS based on the YouTube-VOS-2019 dataset [56]. These datasets typically provide an expression for a single object, and the expression usually describes the static attributes of the target object, such as its color and shape." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 456, + 289, + 660 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 456, + 289, + 660 + ], + "spans": [ + { + "bbox": [ + 47, + 456, + 289, + 660 + ], + "type": "text", + "content": "Existing methods typically treat referring video segmentation as a form of semi-supervised video object segmentation [41] by replacing mask reference with language reference. For instance, Khoreva et al. [21] employ the referring image segmentation method MAttNet [61] to achieve frame-level segmentation and then perform post-processing for temporal consistency. URVOS [44] employs cross-modal attention to perform per-frame segmentation and propagate the mask across clips with a memory attention module. RefVOS [1] independently segments each frame based on the fused features of language and image/frame, without utilizing temporal information. Liang et al. [26] introduces a top-down approach that first detects all object tracklets and then selects the target object by matching between language and tracklet features. Most recently, ReferFormer [55] and MTTR [2] employ Transformer [47] to address referring video object segmentation." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 670, + 140, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 670, + 140, + 682 + ], + "spans": [ + { + "bbox": [ + 47, + 670, + 140, + 682 + ], + "type": "text", + "content": "3. MeViS Dataset" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 689, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 288, + 715 + ], + "type": "text", + "content": "In this section, we introduce the newly built large-scale dataset MeViS by first presenting the video collection and" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 305, + 72, + 545, + 97 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 97 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 97 + ], + "type": "text", + "content": "annotation process in Section 3.1 and then providing the dataset statistics and analysis in Section 3.2." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 102, + 473, + 115 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 102, + 473, + 115 + ], + "spans": [ + { + "bbox": [ + 306, + 102, + 473, + 115 + ], + "type": "text", + "content": "3.1. Motion Expression Annotation" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 125, + 547, + 186 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 125, + 547, + 186 + ], + "spans": [ + { + "bbox": [ + 305, + 125, + 547, + 186 + ], + "type": "text", + "content": "Video Collection. We gather and choose videos from publicly available video segmentation datasets with high-quality mask annotations [8,42,48,51], and select the ones that meet our criteria for motion and object complexity. Our selection process involves the following rules:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 307, + 188, + 547, + 297 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 307, + 188, + 547, + 260 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 188, + 547, + 260 + ], + "spans": [ + { + "bbox": [ + 307, + 188, + 547, + 260 + ], + "type": "text", + "content": "R1. We only include videos that have multiple objects within the frame in MeViS; videos with only one or two salient objects are not considered. We specifically look for videos that depict many objects with similar appearances, such as the first example video in Figure 1 which shows three yellow parrots." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 307, + 261, + 545, + 297 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 261, + 545, + 297 + ], + "spans": [ + { + "bbox": [ + 307, + 261, + 545, + 297 + ], + "type": "text", + "content": "R2. We select videos that contain objects that demonstrate substantial motion and movement. Videos depicting objects that have little or no motion are excluded." + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 305, + 297, + 547, + 439 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 297, + 547, + 439 + ], + "spans": [ + { + "bbox": [ + 305, + 297, + 547, + 439 + ], + "type": "text", + "content": "After reviewing over 4,000 potential candidates, we carefully selected the most appropriate and suitable videos that meet our rigorous standards for both visual and linguistic content. Ultimately, by prioritizing quality over quantity, we chose 2,006 videos to create a benchmark that is diverse and representative of a wide range of real-world video scenarios. The basic language annotation methodology and procedure for MeViS follow the ReferIt [20], which is an interactive game-like approach that involves two players taking turns to annotate and validate. The following section will introduce the process of language expression annotation and validation in more detail." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 445, + 547, + 578 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 445, + 547, + 578 + ], + "spans": [ + { + "bbox": [ + 305, + 445, + 547, + 578 + ], + "type": "text", + "content": "Language Expression Annotation. We developed a web-based annotation system for annotating language expressions. The system randomly selects a video from the MeViS dataset and displays all object masks of the selected video on the web system. The annotator needs to choose one or several objects from the video and write the corresponding referring expression according to the guidelines for annotating language expressions. To ensure that the language expressions in our dataset align with our focus on motion-based video segmentation, we established several guidelines for annotating the language expressions:" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 582, + 547, + 714 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 306, + 582, + 545, + 617 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 582, + 545, + 617 + ], + "spans": [ + { + "bbox": [ + 306, + 582, + 545, + 617 + ], + "type": "text", + "content": "A1. Target objects must exhibit significant motion. Objects that remain stationary or only demonstrate minimal motion should be disregarded." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 618, + 545, + 654 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 618, + 545, + 654 + ], + "spans": [ + { + "bbox": [ + 306, + 618, + 545, + 654 + ], + "type": "text", + "content": "A2. If an object can be unambiguously described by its motion or action, static attributes such as color should not be included in the expression." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 654, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 654, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 306, + 654, + 547, + 714 + ], + "type": "text", + "content": "A3. If multiple objects cannot be differentiated based solely on their motion or action, they can be described together if their motion or action can unambiguously identify them, such as \"The two lions fighting and running amidst a group of lions.\"" + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 316, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 316, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 316, + 757 + ], + "type": "text", + "content": "2696" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 105, + 544, + 211 + ], + "blocks": [ + { + "bbox": [ + 47, + 70, + 545, + 103 + ], + "lines": [ + { + "bbox": [ + 47, + 70, + 545, + 103 + ], + "spans": [ + { + "bbox": [ + 47, + 70, + 545, + 103 + ], + "type": "text", + "content": "Table 1. Statistics of representative language-guided video segmentation datasets. The newly built MeViS has the largest number of objects and language expressions. More importantly, MeViS focuses on segmenting objects in the videos indicated by motion expressions. The MeViS enables the investigation of the feasibility of using motion expressions for object segmentation and grounding in videos." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 105, + 544, + 211 + ], + "lines": [ + { + "bbox": [ + 48, + 105, + 544, + 211 + ], + "spans": [ + { + "bbox": [ + 48, + 105, + 544, + 211 + ], + "type": "table", + "html": "
DatasetYearPub.VideoObjectExpressionMaskObject/ VideoObject/ ExperisionTarget
A2D Sentence [13]2018CVPR3,7824,8256,65658k1.281Actor
J-HMDB Sentence [13]2018CVPR92892892831.8k11Actor
DAVIS16-RVOS [21]2018ACCV50501003.4k1n/aObject
DAVIS17-RVOS [21]2018ACCV902051,54413.5k2.271Object
Refer-Youtube-VOS [44]2020ECCV3,9787,45115,009131k1.861Object
MeViS (ours)2023ICCV2,0068,17128,570443k4.281.59Object(s)
", + "image_path": "8e9cd45715314365c8256113156da14e3cb84f0effa6a859418adad7c380e805.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 220, + 288, + 257 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 220, + 288, + 257 + ], + "spans": [ + { + "bbox": [ + 47, + 220, + 288, + 257 + ], + "type": "text", + "content": "A4. If it is not possible to differentiate single or multiple objects based solely on their motion or action, limited static attributes can be included in the expression." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 259, + 289, + 488 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 259, + 289, + 488 + ], + "spans": [ + { + "bbox": [ + 47, + 259, + 289, + 488 + ], + "type": "text", + "content": "Language Expression Validation. Upon receiving annotated \"video-object-expression\" samples from the annotators, the validation process begins by displaying the video and expression and prompting the validator to select and submit the objects referred to in the expression. The validator must find the targets independently and submit their selection. The system then compares the targets chosen by the validator with the annotations submitted by the annotator. A sample is considered valid if the validator and annotator independently selected the same target object(s) using the same expression. If the targets selected by the validator do not match the annotation submitted by the annotator, the sample will be forwarded to another validator for a second opinion. If the second validator also fails to identify the correct targets, the sample will be considered invalid and excluded from the dataset. Validator have the authority to reject samples that are deemed inappropriate or fall short of quality standards. Moreover, we stress the importance of the following validation criterion:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 491, + 287, + 538 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 491, + 287, + 538 + ], + "spans": [ + { + "bbox": [ + 47, + 491, + 287, + 538 + ], + "type": "text", + "content": "V1. The corresponding sentence will be removed from the dataset when the target object described by a sentence can be identified through a single frame without the need for motion information." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 543, + 287, + 615 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 543, + 287, + 615 + ], + "spans": [ + { + "bbox": [ + 47, + 543, + 287, + 615 + ], + "type": "text", + "content": "By establishing these validation criteria, we aim to ensure that the language sentences in our dataset accurately express motion and are of high quality, while also increasing the level of difficulty in the language-guided video segmentation task, thereby enabling a more robust evaluation of the performance of different models and methods." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 623, + 212, + 635 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 623, + 212, + 635 + ], + "spans": [ + { + "bbox": [ + 47, + 623, + 212, + 635 + ], + "type": "text", + "content": "3.2. Dataset Analysis and Statistics" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 641, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 641, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 641, + 288, + 713 + ], + "type": "text", + "content": "In Table 1, we present a statistical analysis of the newly proposed MeViS dataset, using 5 previous referring video object segmentation datasets as references, including A2D Sentence [13], J-HMDB Sentence [13], DAVIS16-RVOS [21], DAVIS17-RVOS [21], and Refer-Youtu-VOS [44]. As shown in Table 1, MeViS contains 2,006" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 305, + 222, + 422, + 308 + ], + "blocks": [ + { + "bbox": [ + 305, + 222, + 422, + 308 + ], + "lines": [ + { + "bbox": [ + 305, + 222, + 422, + 308 + ], + "spans": [ + { + "bbox": [ + 305, + 222, + 422, + 308 + ], + "type": "image", + "image_path": "91e79fe0ba098408afe6c3ce645eb1c40f1cb0de82c58f7f0f5de053e295826e.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 334, + 310, + 413, + 319 + ], + "lines": [ + { + "bbox": [ + 334, + 310, + 413, + 319 + ], + "spans": [ + { + "bbox": [ + 334, + 310, + 413, + 319 + ], + "type": "text", + "content": "(a). Durations of videos" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 426, + 224, + 542, + 308 + ], + "blocks": [ + { + "bbox": [ + 426, + 224, + 542, + 308 + ], + "lines": [ + { + "bbox": [ + 426, + 224, + 542, + 308 + ], + "spans": [ + { + "bbox": [ + 426, + 224, + 542, + 308 + ], + "type": "image", + "image_path": "3bcf24c16111896ff871da85d13aa868af05898d64d0d73c95b5eef6a69e266e.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 454, + 310, + 534, + 320 + ], + "lines": [ + { + "bbox": [ + 454, + 310, + 534, + 320 + ], + "spans": [ + { + "bbox": [ + 454, + 310, + 534, + 320 + ], + "type": "text", + "content": "(b). Durations of objects" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 304, + 326, + 545, + 381 + ], + "lines": [ + { + "bbox": [ + 304, + 326, + 545, + 381 + ], + "spans": [ + { + "bbox": [ + 304, + 326, + 545, + 381 + ], + "type": "text", + "content": "Figure 2. The duration of videos and objects of MeViS and Refer-Youtu-VOS [44], in seconds. The vertical lines and values in the legends represent the mean duration across the two datasets. The duration of both videos and objects in MeViS is significantly longer than Refer-Youtu-VOS." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 388, + 546, + 484 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 388, + 546, + 484 + ], + "spans": [ + { + "bbox": [ + 304, + 388, + 546, + 484 + ], + "type": "text", + "content": "videos and 8,171 objects. Compared to Refer-Youtu-VOS [44], which is based on the existing VOS dataset [56], MeViS has more objects (8,171 vs. 7,451), more expressions (28,570 vs. 15,009), and more annotation masks (443k vs. 131k). In the following, we discuss how the proposed dataset MeViS intentionally increases the complexities of language-guided video segmentation by considering the challenges of both linguistic and visual modalities." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 486, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 486, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 486, + 547, + 713 + ], + "type": "text", + "content": "- Video Content. As shown in Table 1, MeViS has an average of 4.28 objects per video, which is higher than previous datasets. Furthermore, as depicted in Figure 2, MeViS contains longer videos, with an average duration of 13.16 seconds, which is significantly longer than the Refer-Youtu-VOS dataset. These intentional design choices make MeViS more complex and challenging for language-guided video segmentation. This is in contrast to existing datasets such as A2D Sentence [13] and " + }, + { + "bbox": [ + 304, + 486, + 547, + 713 + ], + "type": "inline_equation", + "content": "\\mathrm{DAVIS}_{16}" + }, + { + "bbox": [ + 304, + 486, + 547, + 713 + ], + "type": "text", + "content": "-RVOS [21], where only one or two salient objects per category are present, and the model can choose the most prominent object as the target or identify the target object based on the category name. For example, in Figure 3(b), there is only one person in the foreground, and the model can simply identify the target by the term \"a person\" while ignoring \"skateboarding\". The proposed MeViS dataset addresses this limitation by selecting videos with more objects that have diverse and dynamic motions. Moreover, MeViS features many videos with objects of the same" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2697" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 71, + 108, + 114 + ], + "blocks": [ + { + "bbox": [ + 49, + 71, + 108, + 114 + ], + "lines": [ + { + "bbox": [ + 49, + 71, + 108, + 114 + ], + "spans": [ + { + "bbox": [ + 49, + 71, + 108, + 114 + ], + "type": "image", + "image_path": "0a1a18c9b085aeeee3868d49011958feb59058ac745b980f1d4914ba89b5a405.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 57, + 118, + 100, + 133 + ], + "lines": [ + { + "bbox": [ + 57, + 118, + 100, + 133 + ], + "spans": [ + { + "bbox": [ + 57, + 118, + 100, + 133 + ], + "type": "text", + "content": "(a). \"Giraffes turning around\"" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 109, + 71, + 166, + 106 + ], + "blocks": [ + { + "bbox": [ + 109, + 71, + 166, + 106 + ], + "lines": [ + { + "bbox": [ + 109, + 71, + 166, + 106 + ], + "spans": [ + { + "bbox": [ + 109, + 71, + 166, + 106 + ], + "type": "image", + "image_path": "348d7f1eef02cebc8db282378e3a12159249290159050ee553109d1016fa7148.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 168, + 71, + 226, + 106 + ], + "blocks": [ + { + "bbox": [ + 168, + 71, + 226, + 106 + ], + "lines": [ + { + "bbox": [ + 168, + 71, + 226, + 106 + ], + "spans": [ + { + "bbox": [ + 168, + 71, + 226, + 106 + ], + "type": "image", + "image_path": "b6f6203cc699a86e138e2fe71378d0dde537384ce1d35e5b977d5202600c9913.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 227, + 72, + 285, + 106 + ], + "blocks": [ + { + "bbox": [ + 227, + 72, + 285, + 106 + ], + "lines": [ + { + "bbox": [ + 227, + 72, + 285, + 106 + ], + "spans": [ + { + "bbox": [ + 227, + 72, + 285, + 106 + ], + "type": "image", + "image_path": "ca17754a7f92310e0e97932cbabd6b1e9f8d7132d7082bd3214b0dff0f9b8425.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 49, + 158, + 108, + 194 + ], + "blocks": [ + { + "bbox": [ + 49, + 158, + 108, + 194 + ], + "lines": [ + { + "bbox": [ + 49, + 158, + 108, + 194 + ], + "spans": [ + { + "bbox": [ + 49, + 158, + 108, + 194 + ], + "type": "image", + "image_path": "261bd9855e5d96bf79a1eb6c252cc4d0ae0c69a6cd6b3fb5b2344b1629eabeeb.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 48, + 194, + 108, + 209 + ], + "lines": [ + { + "bbox": [ + 48, + 194, + 108, + 209 + ], + "spans": [ + { + "bbox": [ + 48, + 194, + 108, + 209 + ], + "type": "text", + "content": "(b). \"A person skating.\"" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 109, + 107, + 166, + 144 + ], + "blocks": [ + { + "bbox": [ + 109, + 107, + 166, + 144 + ], + "lines": [ + { + "bbox": [ + 109, + 107, + 166, + 144 + ], + "spans": [ + { + "bbox": [ + 109, + 107, + 166, + 144 + ], + "type": "image", + "image_path": "f3b8980f8d7e10d8ff32851925089019a1d7608343c81c03f65c9d179db4efda.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 168, + 108, + 226, + 144 + ], + "blocks": [ + { + "bbox": [ + 168, + 108, + 226, + 144 + ], + "lines": [ + { + "bbox": [ + 168, + 108, + 226, + 144 + ], + "spans": [ + { + "bbox": [ + 168, + 108, + 226, + 144 + ], + "type": "image", + "image_path": "2ec54f5790388ed9254cd9fb1848553b4497c339c8fabf556eda75c28bded610.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 227, + 108, + 285, + 144 + ], + "blocks": [ + { + "bbox": [ + 227, + 108, + 285, + 144 + ], + "lines": [ + { + "bbox": [ + 227, + 108, + 285, + 144 + ], + "spans": [ + { + "bbox": [ + 227, + 108, + 285, + 144 + ], + "type": "image", + "image_path": "9c3c32a99fd22281b498cbf3ee65231f7c32d91408abb16fc479b7076b9ab860.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 109, + 146, + 166, + 182 + ], + "blocks": [ + { + "bbox": [ + 109, + 146, + 166, + 182 + ], + "lines": [ + { + "bbox": [ + 109, + 146, + 166, + 182 + ], + "spans": [ + { + "bbox": [ + 109, + 146, + 166, + 182 + ], + "type": "image", + "image_path": "10ebd9dda2a8f987720960a73ae5cacb16ac3c80f72ad539c995cb75e6a98e14.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 168, + 146, + 226, + 182 + ], + "blocks": [ + { + "bbox": [ + 168, + 146, + 226, + 182 + ], + "lines": [ + { + "bbox": [ + 168, + 146, + 226, + 182 + ], + "spans": [ + { + "bbox": [ + 168, + 146, + 226, + 182 + ], + "type": "image", + "image_path": "ce2af727ab62078d03844def69a37e0789c17e7dbbd030349423e33e658a3b60.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 227, + 147, + 285, + 182 + ], + "blocks": [ + { + "bbox": [ + 227, + 147, + 285, + 182 + ], + "lines": [ + { + "bbox": [ + 227, + 147, + 285, + 182 + ], + "spans": [ + { + "bbox": [ + 227, + 147, + 285, + 182 + ], + "type": "image", + "image_path": "2ccd32f87cc5d8e2f5506bfe3f07567ad948a59a77ad3e0f76f5b4a4182698e4.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 109, + 183, + 166, + 218 + ], + "blocks": [ + { + "bbox": [ + 109, + 183, + 166, + 218 + ], + "lines": [ + { + "bbox": [ + 109, + 183, + 166, + 218 + ], + "spans": [ + { + "bbox": [ + 109, + 183, + 166, + 218 + ], + "type": "image", + "image_path": "ef8f1e1c43e5f891870fbef2cb9d0c2e0f17a16290589157696f9e22fae02136.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 220, + 287, + 286 + ], + "lines": [ + { + "bbox": [ + 46, + 220, + 287, + 286 + ], + "spans": [ + { + "bbox": [ + 46, + 220, + 287, + 286 + ], + "type": "text", + "content": "Figure 3. (a) Example from MeViS. (b) Example from Refer-Youtu-VOS [44]. Compared to Refer-Youtu-VOS: " + }, + { + "bbox": [ + 46, + 220, + 287, + 286 + ], + "type": "inline_equation", + "content": "\\bullet" + }, + { + "bbox": [ + 46, + 220, + 287, + 286 + ], + "type": "text", + "content": " Videos in MeViS contain more objects in complex environments, making it impossible to identify the target object via saliency or category information alone. " + }, + { + "bbox": [ + 46, + 220, + 287, + 286 + ], + "type": "inline_equation", + "content": "\\bullet" + }, + { + "bbox": [ + 46, + 220, + 287, + 286 + ], + "type": "text", + "content": " The number of target objects indicated by language expression in MeViS is arbitrary, from 1 to many." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 168, + 183, + 225, + 218 + ], + "blocks": [ + { + "bbox": [ + 168, + 183, + 225, + 218 + ], + "lines": [ + { + "bbox": [ + 168, + 183, + 225, + 218 + ], + "spans": [ + { + "bbox": [ + 168, + 183, + 225, + 218 + ], + "type": "image", + "image_path": "5b8e39569cd5fc3da8741927284d6d3611a7e4f594c36557d09743fbc948810d.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 227, + 183, + 285, + 218 + ], + "blocks": [ + { + "bbox": [ + 227, + 183, + 285, + 218 + ], + "lines": [ + { + "bbox": [ + 227, + 183, + 285, + 218 + ], + "spans": [ + { + "bbox": [ + 227, + 183, + 285, + 218 + ], + "type": "image", + "image_path": "80ee0ed1a600bacc2a803002840d59b20092e215e0db57c8c308499c84c16d39.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + } + ], + "index": 15 + }, + { + "bbox": [ + 46, + 301, + 287, + 410 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 301, + 287, + 410 + ], + "spans": [ + { + "bbox": [ + 46, + 301, + 287, + 410 + ], + "type": "text", + "content": "category, such as a group of tigers or rabbits. For instance, in Figure 3(a), there are three giraffes with highly similar appearances, and the most salient foreground one is not the target object in this sample, making it challenging to identify the target object(s) through saliency or category information alone. By including more challenging videos, MeViS better simulates real-world scenarios, making it a valuable resource for studying motion expression-guided video understanding in complex environments." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 46, + 413, + 288, + 654 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 413, + 288, + 654 + ], + "spans": [ + { + "bbox": [ + 46, + 413, + 288, + 654 + ], + "type": "text", + "content": "Target Object(s). As we have included longer videos in our MeViS dataset, we have also observed a significant increase in the duration of target objects, ensuring adequate object motions. As shown in Figure 2(b), the object durations in our dataset have an average of 10.88 seconds, which is more than two times longer than the average duration of Refer-Youtu-VOS. Compared to previous datasets, such as A2D Sentence [13] and J-HMDB Sentence [13], which focus on salient actions of a few categories [44], our MeViS dataset includes more categories from open-world [8, 42, 48, 51], presenting improved difficulties in the diversity of target objects. Besides, as shown in Table 1, previous datasets usually have one sentence referring to one single object, which means that finding multiple objects requires multiple expressions, and each object must be searched for individually*. In contrast, we add a more natural way of selecting target objects, where one expression may refer to several objects, denoted as \"multi-object expression\". An example of multi-object expression is shown in Figure 3(a), where \"Giraffes that turns around\" refers to two giraffes." + } + ] + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 310, + 71, + 539, + 185 + ], + "blocks": [ + { + "bbox": [ + 310, + 71, + 539, + 185 + ], + "lines": [ + { + "bbox": [ + 310, + 71, + 539, + 185 + ], + "spans": [ + { + "bbox": [ + 310, + 71, + 539, + 185 + ], + "type": "image", + "image_path": "993fc699d1e1017ad8a285d37aa82df0cda92bccd4744b4f2c46c290fc8ea6c0.jpg" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 189, + 545, + 233 + ], + "lines": [ + { + "bbox": [ + 305, + 189, + 545, + 233 + ], + "spans": [ + { + "bbox": [ + 305, + 189, + 545, + 233 + ], + "type": "text", + "content": "Figure 4. Word cloud of the top 100 words in the MeViS dataset. MeViS has a large number of words that describe motions, like \"walking\", \"moving\", \"playing\", and many position words that are related to motions, such as \"left\", \"right\"." + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_caption" + } + ], + "index": 19 + }, + { + "bbox": [ + 305, + 244, + 545, + 281 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 244, + 545, + 281 + ], + "spans": [ + { + "bbox": [ + 305, + 244, + 545, + 281 + ], + "type": "text", + "content": "As shown in Table 1, on average, each expression in MeViS refers to 1.59 objects, which is larger than existing datasets where the average is only 1 object per expression." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 283, + 546, + 619 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 283, + 546, + 619 + ], + "spans": [ + { + "bbox": [ + 304, + 283, + 546, + 619 + ], + "type": "text", + "content": "Language Expression. One of the key distinguishing aspects of the MeViS dataset is its emphasis on describing object motions in language expressions. The previous largest RVOS dataset Refer-Youtu-VOS [44] provides two types of language annotations: full-video expression and first-frame expression. The first-frame expression is based solely on static attributes of the first frame image, whereas the full-video expression considers the entire video. However, in many cases, even the full-video expressions contain static attributes that could potentially enable the target object to be identified in a single frame, for example, \"A person on the right dressed in blue black...\". In contrast, to explore the practicality of employing motion expressions for object localization and segmentation in videos, MeViS is intentionally designed to include a range of diverse and dynamic object motions, making it more challenging to identify the target object based on static attributes alone. In MeViS, there are significantly more motion expressions that explicitly identify the target object based on its distinctive actions or movements. The language expressions in the proposed MeViS contain more motion attributes, such as object position moving through the video and actions that span several frames. The word cloud of the newly proposed MeViS is visualized in Figure 4. From the word cloud figure, we can observe that MeViS dataset has a large number of words that describe motions, like \"walking\", \"moving\", \"playing\", and many relative directions that are related to motions, such as \"left\", \"right\", etc." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 306, + 628, + 382, + 642 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 628, + 382, + 642 + ], + "spans": [ + { + "bbox": [ + 306, + 628, + 382, + 642 + ], + "type": "text", + "content": "4. Experiment" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 305, + 654, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 654, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 654, + 546, + 713 + ], + "type": "text", + "content": "Evaluation Metrics. Similar to previous studies such as [21,44], we employ two widely used metrics, " + }, + { + "bbox": [ + 305, + 654, + 546, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{I}" + }, + { + "bbox": [ + 305, + 654, + 546, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 654, + 546, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 305, + 654, + 546, + 713 + ], + "type": "text", + "content": ", to assess the performance of methods on the newly proposed MeViS dataset. The region similarity metric " + }, + { + "bbox": [ + 305, + 654, + 546, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{I}" + }, + { + "bbox": [ + 305, + 654, + 546, + 713 + ], + "type": "text", + "content": " computes the Intersection over Union (IoU) of the predicted and" + } + ] + } + ], + "index": 24 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "text", + "content": "*Although some datasets like " + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mathrm{DAVIS}_{16}" + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "text", + "content": "-RVOS [21] contain samples of multiple instances as targets, the mask annotations provided by " + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mathrm{DAVIS}_{16}" + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "text", + "content": " [40] do not distinguish instances, and some target masks cover several instances. Thus, each sample in " + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mathrm{DAVIS}_{16}" + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "text", + "content": "-RVOS can be considered as a single-sentence single-object pair." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2698" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 56, + 121, + 321, + 182 + ], + "blocks": [ + { + "bbox": [ + 46, + 70, + 329, + 117 + ], + "lines": [ + { + "bbox": [ + 46, + 70, + 329, + 117 + ], + "spans": [ + { + "bbox": [ + 46, + 70, + 329, + 117 + ], + "type": "text", + "content": "Table 2. Temporal Context (TC) shows varying impacts on 3 datasets. Image-based methods, like VLT [10], can achieve state-of-the-art performance on " + }, + { + "bbox": [ + 46, + 70, + 329, + 117 + ], + "type": "inline_equation", + "content": "\\mathrm{DAVIS}_{17}" + }, + { + "bbox": [ + 46, + 70, + 329, + 117 + ], + "type": "text", + "content": "-RVOS [21] and Refer-Youtu-VOS (RYV) [44], but cannot well handle the harder motion challenges in MeViS that require temporal context." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 56, + 121, + 321, + 182 + ], + "lines": [ + { + "bbox": [ + 56, + 121, + 321, + 182 + ], + "spans": [ + { + "bbox": [ + 56, + 121, + 321, + 182 + ], + "type": "table", + "html": "
MethodsTypeTemporalDAVIS17-RVOSRYVMeViS
VLT [10]Image1 frame60.463.127.8
RFormer [55]Video5 rand. frames60.262.831.0
VLT+TCVideoAll frames60.362.735.5
RFormer+TCVideoAll frames59.963.036.3
", + "image_path": "1f64620243924b45063cb850c641de30fcfecd616222d6828f8e6637b563c69b.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 191, + 288, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 191, + 288, + 251 + ], + "spans": [ + { + "bbox": [ + 46, + 191, + 288, + 251 + ], + "type": "text", + "content": "ground-truth masks, which reflects the quality of the segmentation. The F-measure " + }, + { + "bbox": [ + 46, + 191, + 288, + 251 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 46, + 191, + 288, + 251 + ], + "type": "text", + "content": " reflects the contour accuracy of the prediction. To provide a comprehensive evaluation of the method's overall effectiveness, we calculate the average of these two metrics, denoted as " + }, + { + "bbox": [ + 46, + 191, + 288, + 251 + ], + "type": "inline_equation", + "content": "\\mathcal{J} \\& \\mathcal{F}" + }, + { + "bbox": [ + 46, + 191, + 288, + 251 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 256, + 288, + 318 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 256, + 288, + 318 + ], + "spans": [ + { + "bbox": [ + 46, + 256, + 288, + 318 + ], + "type": "text", + "content": "Dataset Setting. The MeViS dataset is a large-scale dataset that consists of a total of 2,006 videos along with 28,570 sentences. These videos are split into three subsets, i.e., training set, validation set, and testing set, which contain 1,712 videos, 140 videos, and 154 videos, respectively." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 324, + 227, + 337 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 324, + 227, + 337 + ], + "spans": [ + { + "bbox": [ + 47, + 324, + 227, + 337 + ], + "type": "text", + "content": "4.1. Dataset Necessity and Challenges" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "text", + "content": "To show the necessity and validity of MeViS in motion expression understanding, we compare the results of state-of-the-art referring image segmentation method VLT [10] and referring video segmentation method ReferFormer [55] on " + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathrm{DAVIS}_{17}" + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "text", + "content": "-RVOS [21], Refer-Youtu-VOS [44], and MeViS, as shown in Table 2. When trained on referring video segmentation dataset, such as Refer-Youtu-VOS [44] and testing on itself, the image-based method VLT [10] that does not use any temporal design can achieve exceptional results of " + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "inline_equation", + "content": "60.4\\%" + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{J} \\& \\mathcal{F}" + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "inline_equation", + "content": "63.1\\%" + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{J} \\& \\mathcal{F}" + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "text", + "content": " on video datasets " + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathrm{DAVIS}_{17}" + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "text", + "content": "-RVOS [21] and Refer-Youtu-VOS [44], respectively, which are even better than video method ReferFormer [55]. The results suggest that for " + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathrm{DAVIS}_{17}" + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "text", + "content": "-RVOS [21] and Refer-Youtu-VOS [44], the temporal context is not essential, and image-based methods that use static clues can achieve good performance on these two datasets. However, on the proposed MeViS, VLT [10] only achieves a score of " + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "inline_equation", + "content": "27.8\\%" + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{J} \\& \\mathcal{F}" + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "text", + "content": ", suggesting that referring image segmentation methods without temporal designs struggle to address the unique challenges presented by videos in our dataset, particularly in handling motion, despite their success on other benchmark datasets. Furthermore, by comparing the results of VLT [10] with ReferFormer [55], which is trained using five randomly selected frames from the video, we find that ReferFormer outperforms VLT by a large margin of " + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "inline_equation", + "content": "3.2\\%" + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "text", + "content": " in terms of " + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{J} \\& \\mathcal{F}" + }, + { + "bbox": [ + 45, + 342, + 289, + 715 + ], + "type": "text", + "content": ". This further highlights the importance of analyzing long-term motions in the MeViS dataset. In order to further prove this point, we enhance VLT and ReferFormer by incorporating an attention module at the head to perceive and gather global temporal context (\"TC\" in Table 2)." + } + ] + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 339, + 129, + 545, + 181 + ], + "blocks": [ + { + "bbox": [ + 337, + 70, + 541, + 126 + ], + "lines": [ + { + "bbox": [ + 337, + 70, + 541, + 126 + ], + "spans": [ + { + "bbox": [ + 337, + 70, + 541, + 126 + ], + "type": "text", + "content": "Table 3. Image-video cross-dataset validation. We train the models on referring image segmentation dataset Ref-COCO+/g, and test their performance on three different video datasets. The models trained on images perform worse on MeViS than on the other two datasets." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 339, + 129, + 545, + 181 + ], + "lines": [ + { + "bbox": [ + 339, + 129, + 545, + 181 + ], + "spans": [ + { + "bbox": [ + 339, + 129, + 545, + 181 + ], + "type": "table", + "html": "
Training on Referring Image Segmentation Dataset
MethodsTypeDAVIS17-RVOSRYVMeViS
VLT [10]Image54.246.122.5
RFormer [55]Video55.645.227.0
", + "image_path": "328ef82cb218000e442417ebcaea7374e3b1e8111af8d9a889fdf7e931fc93da.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 191, + 545, + 286 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 191, + 545, + 286 + ], + "spans": [ + { + "bbox": [ + 304, + 191, + 545, + 286 + ], + "type": "text", + "content": "For module details, please refer to \"Motion Perception\" in Section 4.2. Adding temporal context via this module results in both VLT and ReferFormer achieving a performance gain of approximately " + }, + { + "bbox": [ + 304, + 191, + 545, + 286 + ], + "type": "inline_equation", + "content": "5\\%" + }, + { + "bbox": [ + 304, + 191, + 545, + 286 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 304, + 191, + 545, + 286 + ], + "type": "text", + "content": ", underscoring the significance of temporal context for MeViS. However, it is worth noting that longer temporal information does not necessarily lead to better performance on " + }, + { + "bbox": [ + 304, + 191, + 545, + 286 + ], + "type": "inline_equation", + "content": "\\mathrm{DAVIS}_{17}" + }, + { + "bbox": [ + 304, + 191, + 545, + 286 + ], + "type": "text", + "content": "-RVOS and Refer-Youtu-VOS." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 288, + 546, + 480 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 288, + 546, + 480 + ], + "spans": [ + { + "bbox": [ + 304, + 288, + 546, + 480 + ], + "type": "text", + "content": "We also conduct a cross-dataset experiment by training on referring image segmentation datasets and testing on referring video segmentation datasets. The results in Table 3 show that both the image-based method VLT [10] and video-based method ReferFormer [55] achieve competitive results on Refer-Youtu-VOS [44] and " + }, + { + "bbox": [ + 304, + 288, + 546, + 480 + ], + "type": "inline_equation", + "content": "\\mathrm{DAVIS}_{17}" + }, + { + "bbox": [ + 304, + 288, + 546, + 480 + ], + "type": "text", + "content": "-RVOS [21] when trained on image datasets Ref-COCO, Ref-COCO+, and Ref-COCOg. These results suggest that the expressions in Refer-Youtu-VOS [44] and DAVIS17-RVOS [21] provide static clues like in the image domain, and many target objects can be identified by examining a single frame solely. In contrast, when trained on referring image segmentation datasets and tested on MeViS, both VLT [10] and ReferFormer [55] perform worse, indicating that there is a significant expression-gap (e.g., static vs. motion) between MeViS and these image domain datasets." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 491, + 504, + 503 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 491, + 504, + 503 + ], + "spans": [ + { + "bbox": [ + 305, + 491, + 504, + 503 + ], + "type": "text", + "content": "4.2. LMPM: A Simple Baseline Approach" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 510, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 510, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 547, + 714 + ], + "type": "text", + "content": "The MeViS dataset introduces unique challenges in detecting and understanding object motions in both video and language contexts. The motions described by language expressions can occur over a random number of frames, making it necessary to capture fleeting actions and movements that occur throughout the entire video. This presents significant challenges for recognizing motions in the video content and the corresponding language expressions. Detecting fleeting actions requires meticulous perceiving of every frame while comprehending complex and extended motion spanning multiple frames requires contextual understanding across the entire duration of the video. Current state-of-the-art methods, such as [2, 11, 55], rely on random sampling of a few frames, which may miss frames containing crucial information described by the given expression. Furthermore, these methods fail to effectively extract temporal contextual information and" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2699" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 70, + 545, + 208 + ], + "blocks": [ + { + "bbox": [ + 51, + 70, + 545, + 208 + ], + "lines": [ + { + "bbox": [ + 51, + 70, + 545, + 208 + ], + "spans": [ + { + "bbox": [ + 51, + 70, + 545, + 208 + ], + "type": "image", + "image_path": "35c8dce7a0cdc952b19d53eaa1f125064dc2e8f988110c7388fed37fbc8f0a43.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 214, + 546, + 270 + ], + "lines": [ + { + "bbox": [ + 46, + 214, + 546, + 270 + ], + "spans": [ + { + "bbox": [ + 46, + 214, + 546, + 270 + ], + "type": "text", + "content": "Figure 5. The overview architecture of the proposed baseline approach Language-guided Motion Perception and Matching (LMPM). We first detect all possible target objects in each frame of the video and use object embeddings to represent them through Language-Guided Extractor. Then, Motion Perception is conducted on all the object embeddings of the video to grasp the global temporal context. By leveraging language queries and object embeddings with motion information, we generate object trajectories through a Transformer Decoder. Finally, we match the language features with the predicted object trajectories to identify the target object(s)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 286, + 288, + 358 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 286, + 288, + 358 + ], + "spans": [ + { + "bbox": [ + 46, + 286, + 288, + 358 + ], + "type": "text", + "content": "instead simply use spatial-temporal feature extractors due to the significant burden on computational resources of temporal communication. Additionally, as illustrated in Section 3, objects described by language expressions can vary from one to multiple, requiring the output to cover from one to an arbitrary number of objects." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "text", + "content": "To address the challenges posed by the MeViS dataset, we propose a baseline approach called Language-guided Motion Perception and Matching (LMPM), which is depicted in Figure 5. LMPM generates " + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "inline_equation", + "content": "N_{1}" + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "text", + "content": " language-based queries to identify potential target objects in the video, across " + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "text", + "content": " frames, and produces object embeddings to represent each of them. Using language queries instead of conventional object queries can filter out irrelevant objects and ensure the efficiency and effectiveness of subsequent operations [9, 10]. Inspired by VITA [15], we represent objects using object embeddings, which provide instance-specific information, to reduce computational requirements [24, 25]. After obtaining object embeddings from frames in the video, we perform motion perception by inter-frame self-attention on the object embeddings to obtain a global view across " + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "text", + "content": " frames. Motion perception enables object embeddings to capture temporal contextual information that spans multiple frames, or even the entire video. Then, we use " + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "inline_equation", + "content": "N_{2}" + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "text", + "content": " language queries as the query and the object embeddings after Motion Perception as the key and value for the Transformer decoder. The Transformer decoder decodes language-related information from all object embeddings and aggregates relevant information to predict object trajectories. Finally, we match the language features with the predicted object trajectories to identify the target object(s). Rather than only selecting the best-matched object trajectory, we use a matching threshold " + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "text", + "content": " to choose object trajectories only if their similarity with the language features exceeds the threshold " + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 46, + 366, + 288, + 713 + ], + "type": "text", + "content": ". This enables the model" + } + ] + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 310, + 298, + 542, + 351 + ], + "blocks": [ + { + "bbox": [ + 321, + 285, + 529, + 296 + ], + "lines": [ + { + "bbox": [ + 321, + 285, + 529, + 296 + ], + "spans": [ + { + "bbox": [ + 321, + 285, + 529, + 296 + ], + "type": "text", + "content": "Table 4. Ablation study of the baseline approach LMPM." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 310, + 298, + 542, + 351 + ], + "lines": [ + { + "bbox": [ + 310, + 298, + 542, + 351 + ], + "spans": [ + { + "bbox": [ + 310, + 298, + 542, + 351 + ], + "type": "table", + "html": "
IDLanguage QueryMotion PerceptionMatchingJ&F
i✓××31.0
ii✓✓×36.3
iii✓✓✓37.2
", + "image_path": "5ad0bc24b72a260829d1d5fe8513de46d3187f26d1bb1d89f0d2c501241112b0.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 356, + 545, + 380 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 356, + 545, + 380 + ], + "spans": [ + { + "bbox": [ + 305, + 356, + 545, + 380 + ], + "type": "text", + "content": "to handle not only single-object expressions but also multi-object expressions, which is a unique feature of MeViS." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 385, + 546, + 540 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 385, + 546, + 540 + ], + "spans": [ + { + "bbox": [ + 304, + 385, + 546, + 540 + ], + "type": "text", + "content": "Implementation Details. We set all the hyper-parameters related to the Language-Guided Extractor to the default settings of Mask2Former [4], including the backbone, Transformer decoder. We train 150,000 iterations using AdamW optimizer [35] with a learning rate of 0.00005. Tiny Swin Transformer [33] is employed as our backbone in all the experiments. The input frames are resized to have a minimum size of 448 pixels on the shorter side during inference. Motion Perception consists of six layers, and the Transformer decoder employs three layers. For the hyperparameter settings, we set " + }, + { + "bbox": [ + 304, + 385, + 546, + 540 + ], + "type": "inline_equation", + "content": "\\sigma" + }, + { + "bbox": [ + 304, + 385, + 546, + 540 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 385, + 546, + 540 + ], + "type": "inline_equation", + "content": "N_{1}" + }, + { + "bbox": [ + 304, + 385, + 546, + 540 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 385, + 546, + 540 + ], + "type": "inline_equation", + "content": "N_{2}" + }, + { + "bbox": [ + 304, + 385, + 546, + 540 + ], + "type": "text", + "content": " to 0.8, 20, and 10, respectively. We use RoBERTa [32] as a text encoder that is consistent with the ReferFormer and is frozen all the time." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "type": "text", + "content": "Ablation study of LMPM. In Table 4, we present an ablation study of the baseline approach LMPM. We perform the following three experiments: (i) First, we use language queries to detect potential target object trajectories and output the best trajectory, similar to ReferFormer [55]. This variant achieves a " + }, + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "type": "text", + "content": " score of " + }, + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "type": "inline_equation", + "content": "31.0\\%" + }, + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "type": "text", + "content": ". It relies solely on language information with 5 randomly sampled frames and neglects global temporal context across the video, making it unable to effectively process long-term motions. (ii) With the help of Motion Perception, the " + }, + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "type": "text", + "content": " score significantly improves by " + }, + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "type": "inline_equation", + "content": "5.3\\%" + }, + { + "bbox": [ + 304, + 545, + 547, + 715 + ], + "type": "text", + "content": ", as it captures temporal contextual information and a global view of the entire video, which are critical for MeViS. (iii) Since MeViS contains multi-objects expressions, outputting only the object with" + } + ] + } + ], + "index": 8 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2700" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 49, + 83, + 286, + 165 + ], + "blocks": [ + { + "bbox": [ + 100, + 71, + 234, + 80 + ], + "lines": [ + { + "bbox": [ + 100, + 71, + 234, + 80 + ], + "spans": [ + { + "bbox": [ + 100, + 71, + 234, + 80 + ], + "type": "text", + "content": "Table 5. MeViS Benchmark Results." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 49, + 83, + 286, + 165 + ], + "lines": [ + { + "bbox": [ + 49, + 83, + 286, + 165 + ], + "spans": [ + { + "bbox": [ + 49, + 83, + 286, + 165 + ], + "type": "table", + "html": "
MethodsJ&FJF
URVOS [44]27.825.729.9
LBDT [11]29.327.830.8
MTTR [2]30.028.831.2
ReferFormer [55]31.029.832.2
VLT+TC [10]35.533.637.3
LMPM (ours)37.234.240.2
", + "image_path": "93a96be995b8746bdf45bad313341efddd5470aba9ac4ba75c2b954b6730c4b7.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 184, + 287, + 244 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 184, + 287, + 244 + ], + "spans": [ + { + "bbox": [ + 46, + 184, + 287, + 244 + ], + "type": "text", + "content": "the highest score is insufficient. We introduce a matching mechanism to identify the target object(s), enabling our method to handle not only single-object expressions but also multi-object expressions. This variant outperforms (ii) by " + }, + { + "bbox": [ + 46, + 184, + 287, + 244 + ], + "type": "inline_equation", + "content": "0.9\\%" + }, + { + "bbox": [ + 46, + 184, + 287, + 244 + ], + "type": "text", + "content": " in terms of " + }, + { + "bbox": [ + 46, + 184, + 287, + 244 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 46, + 184, + 287, + 244 + ], + "type": "text", + "content": " score." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 255, + 196, + 266 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 255, + 196, + 266 + ], + "spans": [ + { + "bbox": [ + 47, + 255, + 196, + 266 + ], + "type": "text", + "content": "4.3. MeViS Benchmark Results" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "spans": [ + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "text", + "content": "Quantitative results. We performed a comprehensive evaluation of the MeViS dataset to assess the performance of existing methods in the more challenging motion-expression scenarios. We evaluated 1 modified image-based method VLT [10] and 4 recent state-of-the-art video-based methods, including URVOS [44], LBDT [11], MTTR [2], and ReferFormer [55], on the validation set" + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "inline_equation", + "content": "^{\\dagger}" + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "text", + "content": " of MeViS. The evaluation results, presented in Table 5, indicate that the current state-of-the-art methods could only achieve performance ranging from " + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "inline_equation", + "content": "27.8\\%" + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "inline_equation", + "content": "31.0\\%" + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "text", + "content": " on the validation set of MeViS, while their results on other benchmarks like Refer-Youtu-VOS [44] and DAVIS" + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "inline_equation", + "content": "_{17}" + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "text", + "content": "-RVOS [21] are usually above " + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "inline_equation", + "content": "60\\%" + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "inline_equation", + "content": "\\mathcal{J}\\& \\mathcal{F}" + }, + { + "bbox": [ + 46, + 272, + 287, + 536 + ], + "type": "text", + "content": ". Our experiments demonstrate that while notable progress has been made in language-guided video object segmentation on existing benchmarks, the challenges presented by MeViS underline the need for further exploration of motion expression-guided video segmentation in complex scenarios. These challenges can arise from various factors, including both linguistic and visual modalities, such as the use of motion expressions and highly dynamic objects or fast-paced motions in videos, which can impact the overall performance of algorithms." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 540, + 287, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 540, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 540, + 287, + 696 + ], + "type": "text", + "content": "Visualizations. Figure 6 displays some of the success and failure cases of the baseline approach LMPM. Example (a) and (b) depict successful cases where LMPM effectively processes expressions of long-term motions such as \"moving to the front ...\" and \"goes out of the screen\". In contrast, example (c) and (d) are failure cases. In example (c), the expression involves the target object disappearing and reappearing, which poses a significant challenge for the model's global understanding of the video. In this case, our model becomes disoriented after the target object reappears. Example (d) shows a sentence describing a long-term motion while involving multiple target objects. Our method successfully identifies the multiple targets, i.e., the" + } + ] + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 307, + 71, + 544, + 101 + ], + "blocks": [ + { + "bbox": [ + 307, + 71, + 544, + 101 + ], + "lines": [ + { + "bbox": [ + 307, + 71, + 544, + 101 + ], + "spans": [ + { + "bbox": [ + 307, + 71, + 544, + 101 + ], + "type": "image", + "image_path": "58f8e788fb86e04d6894ac76c8076d5a0567f8c85605d33759136bd191c7405c.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 325, + 102, + 522, + 109 + ], + "lines": [ + { + "bbox": [ + 325, + 102, + 522, + 109 + ], + "spans": [ + { + "bbox": [ + 325, + 102, + 522, + 109 + ], + "type": "text", + "content": "(a). \"The monkey moving to the front of another monkey, and turning\"" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 308, + 110, + 544, + 140 + ], + "blocks": [ + { + "bbox": [ + 308, + 110, + 544, + 140 + ], + "lines": [ + { + "bbox": [ + 308, + 110, + 544, + 140 + ], + "spans": [ + { + "bbox": [ + 308, + 110, + 544, + 140 + ], + "type": "image", + "image_path": "320ef5dd75b619d0406fa231e31187eaf0c3e7c116dd517032f9a2495cfeaf00.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 345, + 140, + 504, + 148 + ], + "lines": [ + { + "bbox": [ + 345, + 140, + 504, + 148 + ], + "spans": [ + { + "bbox": [ + 345, + 140, + 504, + 148 + ], + "type": "text", + "content": "(b). \"The panda that goes out of the screen towards left\"" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 308, + 148, + 544, + 178 + ], + "blocks": [ + { + "bbox": [ + 308, + 148, + 544, + 178 + ], + "lines": [ + { + "bbox": [ + 308, + 148, + 544, + 178 + ], + "spans": [ + { + "bbox": [ + 308, + 148, + 544, + 178 + ], + "type": "image", + "image_path": "9f67730a70d4fea923e3c87690148a83ca422782ec79a7dad0c269fbd1d7e920.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 345, + 179, + 504, + 187 + ], + "lines": [ + { + "bbox": [ + 345, + 179, + 504, + 187 + ], + "spans": [ + { + "bbox": [ + 345, + 179, + 504, + 187 + ], + "type": "text", + "content": "(c). \"The dog that disappears from left, then re-appears\"" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 308, + 188, + 544, + 223 + ], + "blocks": [ + { + "bbox": [ + 308, + 188, + 544, + 223 + ], + "lines": [ + { + "bbox": [ + 308, + 188, + 544, + 223 + ], + "spans": [ + { + "bbox": [ + 308, + 188, + 544, + 223 + ], + "type": "image", + "image_path": "a053ab9b8e2b4ffb8a78a07c8e622f5877b5cf822b8c5cf67dc2c2832c9846e4.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 320, + 224, + 527, + 232 + ], + "lines": [ + { + "bbox": [ + 320, + 224, + 527, + 232 + ], + "spans": [ + { + "bbox": [ + 320, + 224, + 527, + 232 + ], + "type": "text", + "content": "(d). \"Two goats walking from the distance to the front, then turning back\"" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 324, + 236, + 526, + 247 + ], + "lines": [ + { + "bbox": [ + 324, + 236, + 526, + 247 + ], + "spans": [ + { + "bbox": [ + 324, + 236, + 526, + 247 + ], + "type": "text", + "content": "Figure 6. Example success and failure cases of LMPM." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 261, + 545, + 357 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 261, + 545, + 357 + ], + "spans": [ + { + "bbox": [ + 304, + 261, + 545, + 357 + ], + "type": "text", + "content": "\"two goats walking from the distance\", at the beginning of the video. However, one of the targets is lost during the later stages of the video when the motions of objects became complex and tangled. These two failure cases demonstrate the complexity and challenges of MeViS, emphasizing the importance of a strong ability to comprehend the global temporal context of the entire video and to understand the motion expression for models working on MeViS." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 369, + 457, + 381 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 369, + 457, + 381 + ], + "spans": [ + { + "bbox": [ + 306, + 369, + 457, + 381 + ], + "type": "text", + "content": "5. Conclusion and Discussion" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 390, + 545, + 461 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 390, + 545, + 461 + ], + "spans": [ + { + "bbox": [ + 304, + 390, + 545, + 461 + ], + "type": "text", + "content": "The ability to effectively understand and leverage motion expressions as a primary cue for object segmentation in videos remains an unresolved challenge that requires attention in future research. The proposed large-scale benchmark MeViS provides a foundation for developing more advanced language-guided video segmentation algorithms." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 462, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 462, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 462, + 545, + 713 + ], + "type": "text", + "content": "Future Directions. There are many interesting research directions and remaining challenges to be addressed with the MeViS dataset. These include but are not limited to: (i) exploring new techniques for better motion understanding and modeling in both visual and linguistic modalities, (ii) designing more elegant and robust models that can effectively handle diverse motion types spanning across a range of frames, including long-term/short-term and complex motions, (iii) developing advanced models that can handle complex scenes with various types of objects and expressions, (iv) creating more efficient models that can effectively reduce the number of redundant detected objects, (v) designing effective cross-modal fusion methods to better leverage the complementary information between language and visual signals, (vi) investigating the potential of transfer learning and domain adaptation in language-guided video segmentation, and (vii) developing methods that can better handle the open-world concepts in both the visual and linguistic domain. These challenges require significant research efforts to advance the state-of-the-art in language-guided video segmentation." + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 58, + 702, + 282, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 282, + 713 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 282, + 713 + ], + "type": "text", + "content": "The test set is utilized for evaluation during the competition periods." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "2701" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 73, + 289, + 133 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 73, + 289, + 133 + ], + "spans": [ + { + "bbox": [ + 47, + 73, + 289, + 133 + ], + "type": "text", + "content": "Acknowledgement. This study is supported under the RIE2020 Industry Alignment Fund - Industry Collaboration Projects (IAF-ICP) Funding Initiative, as well as cash and in-kind contribution from the industry partner(s). This study is also supported by the research grant of NTU Presidential Postdoctoral Fellowship. The data of MeViS is released for non-commercial research purposes only." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 140, + 106, + 153 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 140, + 106, + 153 + ], + "spans": [ + { + "bbox": [ + 48, + 140, + 106, + 153 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 160, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 18, + "blocks": [ + { + "bbox": [ + 53, + 160, + 287, + 198 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 160, + 287, + 198 + ], + "spans": [ + { + "bbox": [ + 53, + 160, + 287, + 198 + ], + "type": "text", + "content": "[1] Miriam Bellver, Carles Ventura, Carina Silberer, Ioannis Kazakos, Jordi Torres, and Xavier Giro-i Nieto. A closer look at referring expressions for video object segmentation. Multimedia Tools and Applications, 2022. 2, 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 198, + 287, + 236 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 198, + 287, + 236 + ], + "spans": [ + { + "bbox": [ + 53, + 198, + 287, + 236 + ], + "type": "text", + "content": "[2] Adam Botach, Evgenii Zheltonozhskii, and Chaim Baskin. End-to-end referring video object segmentation with multimodal transformers. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 2, 3, 6, 8" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 237, + 287, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 237, + 287, + 274 + ], + "spans": [ + { + "bbox": [ + 53, + 237, + 287, + 274 + ], + "type": "text", + "content": "[3] Weidong Chen, Dexiang Hong, Yuankai Qi, Zhenjun Han, Shuhui Wang, Laiyun Qing, Qingming Huang, and Guorong Li. Multi-attention network for compressed video referring object segmentation. In ACM Int. Conf. Multimedia, 2022. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 274, + 287, + 312 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 274, + 287, + 312 + ], + "spans": [ + { + "bbox": [ + 53, + 274, + 287, + 312 + ], + "type": "text", + "content": "[4] Bowen Cheng, Ishan Misra, Alexander G Schwing, Alexander Kirillov, and Rohit Girdhar. Masked-attention mask transformer for universal image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 7" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 312, + 287, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 312, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 53, + 312, + 287, + 342 + ], + "type": "text", + "content": "[5] Henghui Ding, Scott Cohen, Brian Price, and Xudong Jiang. PhraseClick: toward achieving flexible interactive segmentation by phrase and click. In Proc. Eur. Conf. Comput. Vis., 2020. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 342, + 287, + 378 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 342, + 287, + 378 + ], + "spans": [ + { + "bbox": [ + 53, + 342, + 287, + 378 + ], + "type": "text", + "content": "[6] Henghui Ding, Xudong Jiang, Ai Qun Liu, Nadia Magnenat Thalmann, and Gang Wang. Boundary-aware feature propagation for scene segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2019. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 379, + 287, + 417 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 379, + 287, + 417 + ], + "spans": [ + { + "bbox": [ + 53, + 379, + 287, + 417 + ], + "type": "text", + "content": "[7] Henghui Ding, Xudong Jiang, Bing Shuai, Ai Qun Liu, and Gang Wang. Context contrasted feature and gated multi-scale aggregation for scene segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 418, + 287, + 454 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 418, + 287, + 454 + ], + "spans": [ + { + "bbox": [ + 53, + 418, + 287, + 454 + ], + "type": "text", + "content": "[8] Henghui Ding, Chang Liu, Shuting He, Xudong Jiang, Philip HS Torr, and Song Bai. MOSE: A new dataset for video object segmentation in complex scenes. In Proc. IEEE Int. Conf. Comput. Vis., 2023. 3, 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 456, + 287, + 492 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 456, + 287, + 492 + ], + "spans": [ + { + "bbox": [ + 53, + 456, + 287, + 492 + ], + "type": "text", + "content": "[9] Henghui Ding, Chang Liu, Suchen Wang, and Xudong Jiang. Vision-language transformer and query generation for referring segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2021. 2, 3, 7" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 494, + 287, + 531 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 494, + 287, + 531 + ], + "spans": [ + { + "bbox": [ + 48, + 494, + 287, + 531 + ], + "type": "text", + "content": "[10] Henghui Ding, Chang Liu, Suchen Wang, and Xudong Jiang. VLT: Vision-language transformer and query generation for referring segmentation. IEEE Trans. Pattern Anal. Mach. Intell., 2023. 2, 3, 6, 7, 8" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 532, + 287, + 569 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 532, + 287, + 569 + ], + "spans": [ + { + "bbox": [ + 48, + 532, + 287, + 569 + ], + "type": "text", + "content": "[11] Zihan Ding, Tianrui Hui, Junshi Huang, Xiaoming Wei, Jizhong Han, and Si Liu. Language-bridged spatial-temporal interaction for referring video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 2, 6, 8" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 570, + 287, + 607 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 570, + 287, + 607 + ], + "spans": [ + { + "bbox": [ + 48, + 570, + 287, + 607 + ], + "type": "text", + "content": "[12] Guang Feng, Zhiwei Hu, Lihe Zhang, and Huchuan Lu. Encoder fusion network with co-attention embedding for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 608, + 287, + 636 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 608, + 287, + 636 + ], + "spans": [ + { + "bbox": [ + 48, + 608, + 287, + 636 + ], + "type": "text", + "content": "[13] Kirill Gavrilyuk, Amir Ghodrati, Zhenyang Li, and Cees GM Snoek. Actor and action video segmentation from a sentence. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 1, 2, 3, 4, 5" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 637, + 287, + 655 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 637, + 287, + 655 + ], + "spans": [ + { + "bbox": [ + 48, + 637, + 287, + 655 + ], + "type": "text", + "content": "[14] Kaiming He, Georgia Gkioxari, Piotr Dollar, and Ross Girshick. Mask r-cnn. In Proc. IEEE Int. Conf. Comput. Vis., 2017. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 656, + 287, + 684 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 656, + 287, + 684 + ], + "spans": [ + { + "bbox": [ + 48, + 656, + 287, + 684 + ], + "type": "text", + "content": "[15] Miran Heo, Sukjun Hwang, Seoung Wug Oh, Joon-Young Lee, and Seon Joo Kim. Vita: Video instance segmentation via object token association. In Proc. Adv. Neural Inform. Process. Syst., 2022. 2, 7" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 48, + 685, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 685, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 685, + 287, + 712 + ], + "type": "text", + "content": "[16] Ronghang Hu, Marcus Rohrbach, and Trevor Darrell. Segmentation from natural language expressions. In Proc. Eur. Conf. Comput. Vis., 2016. 2" + } + ] + } + ], + "index": 17 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 74, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 37, + "blocks": [ + { + "bbox": [ + 307, + 74, + 545, + 112 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 74, + 545, + 112 + ], + "spans": [ + { + "bbox": [ + 307, + 74, + 545, + 112 + ], + "type": "text", + "content": "[17] Tianrui Hui, Shaofei Huang, Si Liu, Zihan Ding, Guanbin Li, Wenguan Wang, Jizhong Han, and Fei Wang. Collaborative spatial-temporal modeling for language-queried video actor segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 113, + 545, + 152 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 113, + 545, + 152 + ], + "spans": [ + { + "bbox": [ + 307, + 113, + 545, + 152 + ], + "type": "text", + "content": "[18] Tianrui Hui, Si Liu, Shaofei Huang, Guanbin Li, Sansi Yu, Faxi Zhang, and Jizhong Han. Linguistic structure guided context modeling for referring image segmentation. In Proc. Eur. Conf. Comput. Vis., 2020. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 152, + 545, + 190 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 190 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 190 + ], + "type": "text", + "content": "[19] Ya Jing, Tao Kong, Wei Wang, Liang Wang, Lei Li, and Tieniu Tan. Locate then segment: A strong pipeline for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 191, + 545, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 191, + 545, + 239 + ], + "spans": [ + { + "bbox": [ + 307, + 191, + 545, + 239 + ], + "type": "text", + "content": "[20] Sahar Kazemzadeh, Vicente Ordonez, Mark Matten, and Tamara Berg. ReferItGame: Referring to objects in photographs of natural scenes. In Proc. of the Conf. on Empirical Methods in Natural Language Process., Doha, Qatar, 2014. Association for Computational Linguistics. 2, 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 240, + 545, + 269 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 240, + 545, + 269 + ], + "spans": [ + { + "bbox": [ + 307, + 240, + 545, + 269 + ], + "type": "text", + "content": "[21] Anna Khoreva, Anna Rohrbach, and Bernt Schiele. Video object segmentation with language referring expressions. In Proc. Asi. Conf. Comput. Vis., 2018. 1, 2, 3, 4, 5, 6, 8" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 270, + 545, + 307 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 270, + 545, + 307 + ], + "spans": [ + { + "bbox": [ + 307, + 270, + 545, + 307 + ], + "type": "text", + "content": "[22] Namyup Kim, Dongwon Kim, Cuiling Lan, Wenjun Zeng, and Suha Kwak. Restr: Convolution-free referring image segmentation using transformers. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 309, + 545, + 346 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 309, + 545, + 346 + ], + "spans": [ + { + "bbox": [ + 307, + 309, + 545, + 346 + ], + "type": "text", + "content": "[23] Ruiyu Li, Kaican Li, Yi-Chun Kuo, Michelle Shu, Xiaojuan Qi, Xiaoyong Shen, and Jiaya Jia. Referring image segmentation via recurrent refinement networks. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 348, + 545, + 387 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 348, + 545, + 387 + ], + "spans": [ + { + "bbox": [ + 307, + 348, + 545, + 387 + ], + "type": "text", + "content": "[24] Xiangtai Li, Henghui Ding, Wenwei Zhang, Haobo Yuan, Jiangmiao Pang, Guangliang Cheng, Kai Chen, Ziwei Liu, and Chen Change Loy. Transformer-based visual segmentation: A survey. arXiv preprint arXiv:2304.09854, 2023. 7" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 388, + 545, + 417 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 388, + 545, + 417 + ], + "spans": [ + { + "bbox": [ + 307, + 388, + 545, + 417 + ], + "type": "text", + "content": "[25] Xiangtai Li, Haobo Yuan, Wenwei Zhang, Guangliang Cheng, Jiangmiao Pang, and Chen Change Loy. Tube-link: A flexible cross tube baseline for universal video segmentation. ICCV, 2023. 7" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 418, + 545, + 456 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 418, + 545, + 456 + ], + "spans": [ + { + "bbox": [ + 307, + 418, + 545, + 456 + ], + "type": "text", + "content": "[26] Chen Liang, Yu Wu, Tianfei Zhou, Wenguan Wang, Zongxin Yang, Yunchao Wei, and Yi Yang. Rethinking cross-modal interaction from a top-down perspective for referring video object segmentation. arXiv preprint arXiv:2106.01061, 2021. 3" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 456, + 545, + 485 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 456, + 545, + 485 + ], + "spans": [ + { + "bbox": [ + 307, + 456, + 545, + 485 + ], + "type": "text", + "content": "[27] Chang Liu, Henghui Ding, and Xudong Jiang. GRES: Generalized referring expression segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2023. 2" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 487, + 545, + 515 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 487, + 545, + 515 + ], + "spans": [ + { + "bbox": [ + 307, + 487, + 545, + 515 + ], + "type": "text", + "content": "[28] Chang Liu, Henghui Ding, Yulun Zhang, and Xudong Jiang. Multimodal mutual attention and iterative interaction for referring image segmentation. IEEE Trans. Image Processing, 2023. 2" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 307, + 517, + 545, + 544 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 517, + 545, + 544 + ], + "spans": [ + { + "bbox": [ + 307, + 517, + 545, + 544 + ], + "type": "text", + "content": "[29] Chang Liu, Xudong Jiang, and Henghui Ding. Instance-specific feature propagation for referring segmentation. IEEE Trans. Multimedia, 2022. 2" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 307, + 546, + 545, + 575 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 546, + 545, + 575 + ], + "spans": [ + { + "bbox": [ + 307, + 546, + 545, + 575 + ], + "type": "text", + "content": "[30] Chenxi Liu, Zhe Lin, Xiaohui Shen, Jimei Yang, Xin Lu, and Alan Yuille. Recurrent multimodal interaction for referring image segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2017. 2" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 307, + 576, + 545, + 605 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 576, + 545, + 605 + ], + "spans": [ + { + "bbox": [ + 307, + 576, + 545, + 605 + ], + "type": "text", + "content": "[31] Si Liu, Tianrui Hui, Shaofei Huang, Yunchao Wei, Bo Li, and Guanbin Li. Cross-modal progressive comprehension for referring segmentation. IEEE Trans. Pattern Anal. Mach. Intell., 2021. 2, 3" + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 307, + 605, + 545, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 605, + 545, + 643 + ], + "spans": [ + { + "bbox": [ + 307, + 605, + 545, + 643 + ], + "type": "text", + "content": "[32] Yinhan Liu, Myle Ott, Naman Goyal, Jingfei Du, Mandar Joshi, Danqi Chen, Omer Levy, Mike Lewis, Luke Zettlemoyer, and Veselin Stoyanov. Roberta: A robustly optimized bert pretraining approach. arXiv preprint arXiv:1907.11692, 2019. 7" + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 307, + 644, + 545, + 683 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 644, + 545, + 683 + ], + "spans": [ + { + "bbox": [ + 307, + 644, + 545, + 683 + ], + "type": "text", + "content": "[33] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In Proc. IEEE Int. Conf. Comput. Vis., 2021. 7" + } + ] + } + ], + "index": 35 + }, + { + "bbox": [ + 307, + 684, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 684, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 684, + 545, + 713 + ], + "type": "text", + "content": "[34] Jonathan Long, Evan Shelhamer, and Trevor Darrell. Fully convolutional networks for semantic segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2015. 2" + } + ] + } + ], + "index": 36 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "2702" + } + ] + } + ], + "index": 38 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 74, + 287, + 585 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 48, + 74, + 286, + 93 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 74, + 286, + 93 + ], + "spans": [ + { + "bbox": [ + 48, + 74, + 286, + 93 + ], + "type": "text", + "content": "[35] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In Proc. Int. Conf. Learn. Represent., 2019. 7" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 95, + 287, + 132 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 95, + 287, + 132 + ], + "spans": [ + { + "bbox": [ + 49, + 95, + 287, + 132 + ], + "type": "text", + "content": "[36] Junhua Mao, Jonathan Huang, Alexander Toshev, Oana Camburu, Alan L Yuille, and Kevin Murphy. Generation and comprehension of unambiguous object descriptions. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2016. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 133, + 287, + 171 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 133, + 287, + 171 + ], + "spans": [ + { + "bbox": [ + 49, + 133, + 287, + 171 + ], + "type": "text", + "content": "[37] Edgar Margffoy-Tuay, Juan C Pérez, Emilio Botero, and Pablo Arbeláez. Dynamic multimodal instance segmentation guided by natural language queries. In Proc. Eur. Conf. Comput. Vis., 2018. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 173, + 286, + 201 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 173, + 286, + 201 + ], + "spans": [ + { + "bbox": [ + 49, + 173, + 286, + 201 + ], + "type": "text", + "content": "[38] Bruce McIntosh, Kevin Duarte, Yogesh S Rawat, and Mubarak Shah. Visual-textual capsule routing for text-based video segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2020. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 203, + 286, + 221 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 203, + 286, + 221 + ], + "spans": [ + { + "bbox": [ + 49, + 203, + 286, + 221 + ], + "type": "text", + "content": "[39] Ke Ning, Lingxi Xie, Fei Wu, and Qi Tian. Polar relative positional encoding for video-language segmentation. In IJCAI, 2020. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 223, + 286, + 270 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 223, + 286, + 270 + ], + "spans": [ + { + "bbox": [ + 49, + 223, + 286, + 270 + ], + "type": "text", + "content": "[40] Federico Perazzi, Jordi Pont-Tuset, Brian McWilliams, Luc Van Gool, Markus Gross, and Alexander Sorkine-Hornung. A benchmark dataset and evaluation methodology for video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2016. 5" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 272, + 286, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 272, + 286, + 308 + ], + "spans": [ + { + "bbox": [ + 49, + 272, + 286, + 308 + ], + "type": "text", + "content": "[41] Jordi Pont-Tuset, Federico Perazzi, Sergi Caelles, Pablo Arbeláez, Alex Sorkine-Hornung, and Luc Van Gool. The 2017 davis challenge on video object segmentation. arXiv preprint arXiv:1704.00675, 2017.3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 311, + 286, + 349 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 311, + 286, + 349 + ], + "spans": [ + { + "bbox": [ + 49, + 311, + 286, + 349 + ], + "type": "text", + "content": "[42] Jiyang Qi, Yan Gao, Yao Hu, Xinggang Wang, Xiaoyu Liu, Xiang Bai, Serge Belongie, Alan Yuille, Philip HS Torr, and Song Bai. Occluded video instance segmentation: A benchmark. Int. J. Comput. Vis., 130(8), 2022. 3, 5" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 350, + 286, + 397 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 350, + 286, + 397 + ], + "spans": [ + { + "bbox": [ + 49, + 350, + 286, + 397 + ], + "type": "text", + "content": "[43] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In Proc. Int. Conf. Mach. Learn., 2021. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 399, + 286, + 436 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 399, + 286, + 436 + ], + "spans": [ + { + "bbox": [ + 49, + 399, + 286, + 436 + ], + "type": "text", + "content": "[44] Seonguk Seo, Joon-Young Lee, and Bohyung Han. Urvos: Unified referring video object segmentation network with a large-scale benchmark. In Proc. Eur. Conf. Comput. Vis., 2020. 1, 2, 3, 4, 5, 6, 8" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 438, + 286, + 475 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 438, + 286, + 475 + ], + "spans": [ + { + "bbox": [ + 49, + 438, + 286, + 475 + ], + "type": "text", + "content": "[45] Mingjie Sun, Jimin Xiao, Eng GEE Lim, and Yao Zhao. Starting point selection and multiple-standard matching for video object segmentation with language annotation. IEEE Trans. Multimedia, 2022. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 49, + 478, + 286, + 515 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 478, + 286, + 515 + ], + "spans": [ + { + "bbox": [ + 49, + 478, + 286, + 515 + ], + "type": "text", + "content": "[46] Zongheng Tang, Yue Liao, Si Liu, Guanbin Li, Xiaojie Jin, Hongxu Jiang, Qian Yu, and Dong Xu. Human-centric spatio-temporal video grounding with visual transformers. IEEE Trans. Circuit Syst. Video Technol., 2021. 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 49, + 517, + 286, + 554 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 517, + 286, + 554 + ], + "spans": [ + { + "bbox": [ + 49, + 517, + 286, + 554 + ], + "type": "text", + "content": "[47] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. In Proc. Adv. Neural Inform. Process. Syst., 2017. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 49, + 556, + 286, + 585 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 556, + 286, + 585 + ], + "spans": [ + { + "bbox": [ + 49, + 556, + 286, + 585 + ], + "type": "text", + "content": "[48] Paul Voigtlaender, Lishu Luo, Chun Yuan, Yong Jiang, and Bastian Leibe. Reducing the annotation effort for video object segmentation datasets. In Proc. IEEE Winter Conf. Appl. Comput. Vis., 2021. 3, 5" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 74, + 545, + 585 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 307, + 74, + 545, + 102 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 74, + 545, + 102 + ], + "spans": [ + { + "bbox": [ + 307, + 74, + 545, + 102 + ], + "type": "text", + "content": "[49] Hao Wang, Cheng Deng, Fan Ma, and Yi Yang. Context modulated dynamic networks for actor and action video segmentation with language queries. In AAAI, 2020. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 103, + 545, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 103, + 545, + 140 + ], + "spans": [ + { + "bbox": [ + 307, + 103, + 545, + 140 + ], + "type": "text", + "content": "[50] Hao Wang, Cheng Deng, Junchi Yan, and Dacheng Tao. Asymmetric cross-guided attention network for actor and action video segmentation from natural language query. In Proc. IEEE Int. Conf. Comput. Vis., 2019. 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 142, + 545, + 170 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 142, + 545, + 170 + ], + "spans": [ + { + "bbox": [ + 307, + 142, + 545, + 170 + ], + "type": "text", + "content": "[51] Weiyao Wang, Matt Feiszli, Heng Wang, and Du Tran. Unidentified video objects: A benchmark for dense, open-world segmentation. In Proc. IEEE Int. Conf. Comput. Vis., 2021. 3, 5" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 171, + 545, + 208 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 171, + 545, + 208 + ], + "spans": [ + { + "bbox": [ + 307, + 171, + 545, + 208 + ], + "type": "text", + "content": "[52] Zhaoqing Wang, Yu Lu, Qiang Li, Xunqiang Tao, Yandong Guo, Mingming Gong, and Tongliang Liu. Cris: Clip-driven referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 209, + 545, + 237 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 209, + 545, + 237 + ], + "spans": [ + { + "bbox": [ + 307, + 209, + 545, + 237 + ], + "type": "text", + "content": "[53] Chenyun Wu, Zhe Lin, Scott Cohen, Trung Bui, and Subhransu Maji. Phrasecut: Language-based image segmentation in the wild. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2020. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 239, + 545, + 276 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 239, + 545, + 276 + ], + "spans": [ + { + "bbox": [ + 307, + 239, + 545, + 276 + ], + "type": "text", + "content": "[54] Dongming Wu, Xingping Dong, Ling Shao, and Jianbing Shen. Multi-level representation learning with semantic alignment for referring video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 277, + 545, + 305 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 277, + 545, + 305 + ], + "spans": [ + { + "bbox": [ + 307, + 277, + 545, + 305 + ], + "type": "text", + "content": "[55] Jiannan Wu, Yi Jiang, Peize Sun, Zehuan Yuan, and Ping Luo. Language as queries for referring video object segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 2, 3, 6, 7, 8" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 306, + 545, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 306, + 545, + 342 + ], + "spans": [ + { + "bbox": [ + 307, + 306, + 545, + 342 + ], + "type": "text", + "content": "[56] Ning Xu, Linjie Yang, Yuchen Fan, Dingcheng Yue, Yuchen Liang, Jianchao Yang, and Thomas Huang. Youtube-vos: A large-scale video object segmentation benchmark. arXiv preprint arXiv:1809.03327, 2018.3,4" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 344, + 545, + 381 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 344, + 545, + 381 + ], + "spans": [ + { + "bbox": [ + 307, + 344, + 545, + 381 + ], + "type": "text", + "content": "[57] Antoine Yang, Antoine Miech, Josef Sivic, Ivan Laptev, and Cordelia Schmid. Tubedetr: Spatio-temporal video grounding with transformers. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 383, + 545, + 411 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 383, + 545, + 411 + ], + "spans": [ + { + "bbox": [ + 307, + 383, + 545, + 411 + ], + "type": "text", + "content": "[58] Sibei Yang, Meng Xia, Guanbin Li, Hong-Yu Zhou, and Yizhou Yu. Bottom-up shift and reasoning for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2021. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 412, + 545, + 449 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 412, + 545, + 449 + ], + "spans": [ + { + "bbox": [ + 307, + 412, + 545, + 449 + ], + "type": "text", + "content": "[59] Zhao Yang, Jiaqi Wang, Yansong Tang, Kai Chen, Hengshuang Zhao, and Philip HS Torr. Levt: Language-aware vision transformer for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 450, + 545, + 479 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 450, + 545, + 479 + ], + "spans": [ + { + "bbox": [ + 307, + 450, + 545, + 479 + ], + "type": "text", + "content": "[60] Linwei Ye, Mrigank Rochan, Zhi Liu, and Yang Wang. Cross-modal self-attention network for referring image segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2019. 3" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 479, + 545, + 517 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 479, + 545, + 517 + ], + "spans": [ + { + "bbox": [ + 307, + 479, + 545, + 517 + ], + "type": "text", + "content": "[61] Licheng Yu, Zhe Lin, Xiaohui Shen, Jimei Yang, Xin Lu, Mohit Bansal, and Tamara L Berg. Mattnet: Modular attention network for referring expression comprehension. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2018. 2, 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 517, + 545, + 546 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 517, + 545, + 546 + ], + "spans": [ + { + "bbox": [ + 307, + 517, + 545, + 546 + ], + "type": "text", + "content": "[62] Licheng Yu, Patrick Poirson, Shan Yang, Alexander C Berg, and Tamara L Berg. Modeling context in referring expressions. In Proc. Eur. Conf. Comput. Vis., 2016. 2" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 547, + 545, + 585 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 547, + 545, + 585 + ], + "spans": [ + { + "bbox": [ + 307, + 547, + 545, + 585 + ], + "type": "text", + "content": "[63] Wangbo Zhao, Kai Wang, Xiangxiang Chu, Fuzhao Xue, Xinchao Wang, and Yang You. Modeling motion with multi-modal features for text-based video segmentation. In Proc. IEEE Conf. Comput. Vis. Pattern Recognit., 2022. 3" + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "2703" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/e2e81f44-6f94-4699-81e2-292ae5d4c0a8_content_list.json b/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/e2e81f44-6f94-4699-81e2-292ae5d4c0a8_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..cec71230f122d1e7ea6badbd22d7a037f115d611 --- /dev/null +++ b/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/e2e81f44-6f94-4699-81e2-292ae5d4c0a8_content_list.json @@ -0,0 +1,1615 @@ +[ + { + "type": "text", + "text": "Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning", + "text_level": 1, + "bbox": [ + 94, + 130, + 875, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Fan Lyu, Qing Sun, Fanhua Shang, Liang Wan, Wei Feng* \nCollege of Intelligence and Computing, Tianjin University", + "bbox": [ + 277, + 180, + 717, + 217 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{fanlyu, sssunqing, fhshang, lwan}@tju.edu.cn, wfeng@ieee.org", + "bbox": [ + 215, + 219, + 754, + 234 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 268, + 313, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In Parallel Continual Learning (PCL), the parallel multiple tasks start and end training unpredictably, thus suffering from both training conflict and catastrophic forgetting issues. The two issues are raised because the gradients from parallel tasks differ in directions and magnitudes. Thus, in this paper, we formulate the PCL into a minimum distance optimization problem among gradients and propose an explicit Asymmetric Gradient Distance (AGD) to evaluate the gradient discrepancy in PCL. AGD considers both gradient magnitude ratios and directions, and has a tolerance when updating with a small gradient of inverse direction, which reduces the imbalanced influence of gradients on parallel task training. Moreover, we present a novel Maximum Discrepancy Optimization (MaxDO) strategy to minimize the maximum discrepancy among multiple gradients. Solving by MaxDO with AGD, parallel training reduces the influence of the training conflict and suppresses the catastrophic forgetting of finished tasks. Extensive experiments validate the effectiveness of our approach on three image recognition datasets in task-incremental and class-incremental PCL. Our code is available at https://github.com/fanlyu/maxdo.", + "bbox": [ + 75, + 301, + 473, + 619 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 665, + 209, + 681 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Continual Learning (CL) [25, 27, 31, 43], aims to continuously learn new knowledge from a sequence of tasks with non-overlapping data streams over a lifelong time. In the era of Internet of Things, people are using many smart devices, where multi-source data and tasks would be accessed at any time. A CL system should respond to parallel data streams from multiple devices. We study Parallel Continual Learning (PCL), as shown in Fig. 1, where an unfixed number of tasks are trained in a parallel way at any time. Specifically, according to the access time of each task, PCL builds an adaptive number of parallel data pipes, thus enabling instant response to new-coming tasks without pending.", + "bbox": [ + 75, + 691, + 470, + 875 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Due to the parallel data streams from different tasks, PCL suffers from not only the catastrophic forgetting but the training conflict among parallel tasks. Most existing methods in CL are proposed to tackle the catastrophic forgetting [19, 25], including regularization-based [25, 8, 16, 51, 1], rehearsal-based [31, 9, 21, 4, 41, 36], and architecture-based [33, 49, 39, 38] methods. In PCL, the training processes of different tasks are diverse, i.e., each task starts and ends training unpredictably (see Fig. 1). Thereby the gradient from different task differs in direction and magnitude [50] and may be neutralized. The gradient discrepancies lead to catastrophic forgetting and training conflict issues, which may fail the learning of some tasks. At any time in PCL, therefore, we present that the problem can be formulated to find an optimal gradient in a minimum distance multi-objective optimization, where each objective is to minimize the distance to a target gradient. In general, the distance metric is proportional to the effect of the optimal gradient on the corresponding task.", + "bbox": [ + 500, + 268, + 893, + 542 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In most situations, the mentioned distance metric $D$ between gradients is set to symmetric intuitively, such as the Euclidean distance and cosine distance. In other words, we usually have $D(\\mathbf{x},\\mathbf{y}) = D(\\mathbf{y},\\mathbf{x})$ for any $\\mathbf{x}$ and $\\mathbf{y}$ . However, the gradient influence is imbalanced among parallel tasks in the gradient descent. For example, in Fig. 1, at the marked time, we have three gradients with diverse directions and magnitudes, and updating with any of them provides different influences to the other two. In the minimum distance problem, the optimal solution should have the minimum negative influence on all parallel tasks, but using symmetric metrics means the influences are optimized indistinguishably at the same time. Due to the fact that the gradients are with wide differences, the solution may have large biases, which would get the near-fitting task out of its local minimum but has less impact on a new-coming task.", + "bbox": [ + 496, + 547, + 893, + 790 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "To measure the gradient discrepancy, we hold the opinion that the distance metric in the min-distance problem should be asymmetric. First, though the metric is bound up with both the gradient magnitude and direction, the influences on model training from gradients should be asymmetric, where the model should have more tolerance to small gradients even if they indicate an inverse direction. Second, because", + "bbox": [ + 496, + 795, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 805, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding author.", + "bbox": [ + 94, + 886, + 220, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "11411", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/a910f8f9e525de354fa547a0395dbe3623eb2180fd906b4c69b63ea8fa3b0ecd.jpg", + "image_caption": [ + "Parallel Continual Learning" + ], + "image_footnote": [], + "bbox": [ + 81, + 89, + 442, + 220 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/3dcbca57a3c25f08a3d55998fdd48e2695f8125929ec84d25d5c7d4d79c63141.jpg", + "image_caption": [ + "Gradient Discrepancy", + "Figure 1. Overview of the proposed method in PCL. Left: PCL trains parallel tasks according to their access time without pending. Middle: At any time, gradients from different tasks (corresponding colors) have unpredicted direction and magnitude (the length of vectors). Right: We formulate PCL into a min-distance problem and propose an asymmetric distance for effective optimization." + ], + "image_footnote": [], + "bbox": [ + 452, + 89, + 602, + 220 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/583f6a4cdd92d1fbd35fa1ca0c5854137020753c6baf70de6a5ca8d57ec47c1f.jpg", + "image_caption": [ + "Minimize Asymmetric Distance" + ], + "image_footnote": [], + "bbox": [ + 612, + 90, + 888, + 220 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "gradients are with different magnitudes, the discrepancy between two large gradients is often set to larger than that between small gradients when using symmetric distance, such as Euclidean distance. Directly optimizing using magnitude-aware distance values may lead to the solution close to large gradients and thus hinder the kepping of old tasks. To mitigate the bias from the magnitude difference, it is better to employ the magnitude ratio instead of magnitude itself.", + "bbox": [ + 75, + 309, + 468, + 429 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Motivated by this, in this paper, we propose an explicit measurement for the learning from gradient discrepancy in PCL, named Asymmetric Gradient Distance (AGD), which considers gradient magnitude ratios and directions, and sets a tolerance for smaller gradients. As shown in Fig. 1, the proposed AGD is used in solving the minimum distance problem with multiple gradients from parallel tasks. Then, we propose an effective optimization strategy for minimizing the gradient discrepancy to avoid self-interference. We name the strategy Maximum Discrepancy Optimization (MaxDO), which minimizes the maximum discrepancy from each gradient to the others. Moreover, to address the catastrophic forgetting issue, we follow the rehearsal strategy [31] in traditional CL and build an extra memory data stream. The rehearsal data stream is used to provide a gradient of finished tasks in MaxDO. Solving by MaxDO with AGD, parallel training mitigates the impacts of the diverse training process and slows the catastrophic forgetting of finished tasks. Extensive results on three datasets show the superiority and effectiveness of our approach.", + "bbox": [ + 75, + 429, + 470, + 731 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Our main contributions are three-fold:", + "bbox": [ + 96, + 732, + 349, + 744 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "(1) We formulate the PCL into a minimum distance problem and compare symmetric and asymmetric distances. We show that symmetric metrics are not effective in solving the problem and suggest asymmetric metrics.", + "(2) We propose an asymmetric metric, named AGD, to evaluate the gradient discrepancy, which is proportional to the gradient magnitude ratios and directions. AGD measures the imbalance of gradient influence in PCL.", + "(3) We propose MaxDO for minimizing gradient discrepancy of different tasks, which maximally reduces the" + ], + "bbox": [ + 76, + 750, + 470, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "asymmetric discrepancy from a gradient to the others. MaxDO avoids the self-interference among gradients and reduces training conflict and catastrophic forgetting.", + "bbox": [ + 524, + 309, + 893, + 354 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 367, + 640, + 382 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Continual Learning", + "text_level": 1, + "bbox": [ + 500, + 392, + 689, + 407 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Continual Learning (CL) represents receiving data from new domains continually. In traditional CL, the new domains show up one by one, say serial CL. CL methods can be classified into three kinds. (1) Rehearsal [31, 9, 21, 4, 41, 36, 32], which saves or generates data of old tasks for retraining together with the current training. (2) Regularization [25, 8, 16, 51, 1, 17], which leverages extra regularization terms to consolidate previous knowledge when learning new tasks. (3) Dynamic architecture [33, 49, 39, 38], which freezes task-specific parameters and grows new branches for new tasks automatically. However, most of the existing CL methods are designed for reducing catastrophic forgetting in the serial scenario. Contrastively, in PCL, we need to tackle not only catastrophic forgetting but training conflict among parallel tasks, which is somehow related to multi-task learning.", + "bbox": [ + 496, + 415, + 893, + 642 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. Multi-Task Learning", + "text_level": 1, + "bbox": [ + 500, + 650, + 696, + 666 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Multi-Task Learning (MTL) [7] is used to address multiple tasks with a single model from one to many domains. Traditional MTL solutions can be mainly grouped into feature-based and parameter-based approaches [52]. The feature-based approaches focus on learning common feature representations for multiple tasks [34, 45]. The parameter-based approaches use model parameters in a task to help learn model parameters in other tasks [44, 5, 23]. Recently, some MTL methods propose to find an optimal gradient for updating and can be categorized into three types. (1) Learning-based methods [11], which learn a set of weights by backpropagation. (2) Solving-based methods [40, 29], solve the problem by finding an optimal gradient that is not dominated by the gradient from any task. (3) Calculating-based methods [30, 24, 12, 46, 50, 20, 28] compute the gradient weights", + "bbox": [ + 496, + 672, + 893, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "11412", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "by combining gradients or losses of all tasks. Inspired by MTL, we also formulate the problem into finding an optimal gradient. Specifically, we consider that the optimal gradient should have a small distance to all gradients.", + "bbox": [ + 75, + 90, + 468, + 151 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.3. Asymmetric Metric", + "text_level": 1, + "bbox": [ + 76, + 161, + 264, + 176 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In most situations in neural network, the distance is set to symmetric, e.g., the Euclidean distance. However, the symmetric metric is not always suitable for finding the optimal gradient (see the next section for details). Asymmetric metric [14, 35], also known as quasi-metric [14] or pseudo metric [18, 6], is a generalization of a metric but the symmetry axiom is eliminated in the definition of metric spaces. A classical example of asymmetric metric is the taxicab geometry topology including one-way streets, where a path from point A to B has different streets compared to a path from B to A. In this paper, we propose to measure the gradient discrepancy using an asymmetric metric and raise a novel optimization strategy to minimize the maximum discrepancy.", + "bbox": [ + 75, + 185, + 472, + 383 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Our Approach", + "text_level": 1, + "bbox": [ + 76, + 396, + 225, + 412 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Parallel Continual Learning", + "text_level": 1, + "bbox": [ + 76, + 420, + 331, + 436 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "On a timeline, given a sequence of $T$ tasks with parallel data streams $\\{\\mathcal{D}_1,\\dots ,\\mathcal{D}_T\\}$ for continual training, and each data stream can be accessed and suspended at any time. For simplest, we assume each data stream is i.i.d., and tasks are accessed in order from 1 to $T$ and there exists no real gap that no data stream flows on the timeline. Note that traditional CL is an edge situation of PCL that all tasks are nose-to-tail. A PCL model contains a shared backbone with parameter $\\theta$ to learn task-agnostic knowledge and adaptively incremental number of task-specific classifiers with parameters $\\theta_{i}$ . When a new task is accessed, a corresponding task-specific classifier will be constructed.", + "bbox": [ + 75, + 444, + 472, + 625 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In PCL, a task will be forgotten by learning any other tasks when its data stream ends. To avoid forgetting, we leverage the popular rehearsal strategy [31, 9, 21, 4, 41, 36] in our training. Rehearsal builds an extra data stream sampled from all seen tasks and retrans them to suppress the forgetting of finished tasks. For convenience, we denote the rehearsal data stream as $\\mathcal{D}_0$ . At time $t$ , we use $\\mathcal{T}_t$ to represent the activated data streams (including $\\mathcal{D}_0$ ). Together with the rehearsal data stream, PCL training yields the following dynamic multi-objective empirical risk minimization:", + "bbox": [ + 75, + 626, + 470, + 777 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\min _ {\\boldsymbol {\\theta}, \\left\\{\\boldsymbol {\\theta} _ {i} \\mid i \\in \\mathcal {T} _ {t} \\right\\}} \\quad \\left\\{\\ell_ {i} \\left(\\mathcal {D} _ {i}\\right) \\mid i \\in \\mathcal {T} _ {t} \\right\\}. \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 166, + 789, + 468, + 814 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Because the task-specific classifiers are updated by their own gradients $\\theta_{i}\\gets \\theta_{i} - \\alpha_{i}\\nabla_{\\theta_{i}}\\ell_{i}$ $(\\forall i\\in T_{t})$ with step size $\\alpha_{i}$ , we focus on the update of the shared backbone $\\pmb{\\theta}$ . At any PCL step, the goal of dynamic MOO is to optimize multiple objectives simultaneously while updating only once, and", + "bbox": [ + 75, + 825, + 472, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "the only update of the shared parameters depends on the gradients of all in-training tasks. It will exit an uncertain number of tasks, and each task will provide a task-specific gradient on the shared parameter $\\theta$ . Let $\\mathbf{g}_i = \\nabla_\\theta \\ell_i$ and $\\alpha$ be a step size for optimization. The problem of the backbone update can be formulated as follows:", + "bbox": [ + 496, + 90, + 890, + 181 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {\\theta} \\leftarrow \\boldsymbol {\\theta} - \\alpha \\mathbf {d} ^ {*}, \\quad \\text {w h e r e} \\mathbf {d} ^ {*} = f \\left(\\left\\{\\mathbf {g} _ {i} | \\forall i \\in \\mathcal {T} _ {t} \\right\\}\\right). \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 526, + 188, + 890, + 205 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The key question is how to compute the optimal gradient $\\mathbf{d}^*$ via the function $f(\\cdot)$ . In this paper, we define the function $f(\\cdot)$ as a min-distance multi-objective problem by minimizing the gradient distance from all in-training tasks:", + "bbox": [ + 496, + 212, + 893, + 272 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {d} ^ {*} = \\arg \\min _ {\\mathbf {d}} \\quad \\left\\{D \\left(\\mathbf {d}, \\mathbf {g} _ {i}\\right) \\mid \\forall i \\in \\mathcal {T} \\right\\}, \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 566, + 279, + 890, + 301 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where we need to identify what distance metric $D$ is used to measure gradient discrepancy. The motivation of Eq. (3) is that for the task $i$ in PCL, its own gradient $\\mathbf{g}_i$ is the most qualified update direction for itself. The solution $\\mathbf{d}^*$ should be as close to every gradient as possible.", + "bbox": [ + 496, + 306, + 890, + 382 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "A related but different task is Federated Continual Learning (FCL) [48, 42]. Most FCL methods primarily focus on serial training, involving multiple clients in training a shared task at the same time. It is meaningful to study Federated PCL in the future for the advancement of privacy protection.", + "bbox": [ + 496, + 382, + 893, + 458 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Measuring Asymmetric Gradient Discrepancy", + "text_level": 1, + "bbox": [ + 498, + 465, + 890, + 482 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To measure gradient discrepancy, the Euclidean Distance (EuDist, $D(\\mathbf{x},\\mathbf{y}) = \\| \\mathbf{x} - \\mathbf{y}\\| \\in [0,\\infty)$ ) and Cosine Distance (CosDist, $D(\\mathbf{x},\\mathbf{y}) = 1 - \\frac{\\mathbf{x}^\\top\\mathbf{y}}{\\|\\mathbf{x}\\|\\|\\mathbf{y}\\|} \\in [0,2]$ ) are the two most popular choices. Both of them are symmetric, i.e., $D(\\mathbf{x},\\mathbf{y}) = D(\\mathbf{y},\\mathbf{x})$ . A symmetric metric $D(\\mathbf{x},\\mathbf{y})$ means the forward influence ( $\\mathbf{x}$ to $\\mathbf{y}$ ) and backward influence ( $\\mathbf{y}$ to $\\mathbf{x}$ ) are equal. For example, given two in-training tasks A and B, the distance $D(\\mathbf{g}_{\\mathrm{A}},\\mathbf{g}_{\\mathrm{B}})$ represents both the effect of $\\mathbf{g}_{\\mathrm{A}}$ on task B and $\\mathbf{g}_{\\mathrm{B}}$ on task A because of $D(\\mathbf{g}_{\\mathrm{A}},\\mathbf{g}_{\\mathrm{B}}) = D(\\mathbf{g}_{\\mathrm{B}},\\mathbf{g}_{\\mathrm{A}})$ . Note that large distance from $\\mathbf{g}_{\\mathrm{A}}$ to $\\mathbf{g}_{\\mathrm{B}}$ means large negative influence on the training of task B with $\\mathbf{g}_{\\mathrm{A}}$ .", + "bbox": [ + 496, + 488, + 893, + 657 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "However, the model update is highly related to gradient magnitude and direction, which are asymmetric to model updating. The influence of the gradient $\\mathbf{g}_{\\mathrm{A}}$ on task B may be quite different from that of the gradient $\\mathbf{g}_{\\mathrm{B}}$ on task A. In previous studies [31, 9, 50], the two tasks are treated as conflict when $\\langle \\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}} \\rangle < 0$ . In PCL, due to the diverse training process, gradients from parallel tasks are diverse in magnitude and direction. When $\\| \\mathbf{g}_{\\mathrm{A}} \\| \\ll \\| \\mathbf{g}_{\\mathrm{B}} \\|$ , the gradient $\\mathbf{g}_{\\mathrm{A}}$ will have little negative influence on task B even if $\\langle \\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}} \\rangle < 0$ ; when $\\| \\mathbf{g}_{\\mathrm{A}} \\| \\gg \\| \\mathbf{g}_{\\mathrm{B}} \\|$ (e.g., a new task A is accessed when task B has been trained for some time near convergence), the update produces huge impact on task B even if $\\langle \\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}} \\rangle > 0$ . Using traditional symmetric distances can hardly represent the asymmetric update influence difference.", + "bbox": [ + 496, + 659, + 893, + 869 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To effectively measure gradient discrepancy in PCL, we introduce the asymmetric metric.", + "bbox": [ + 498, + 869, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "11413", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/d817f0f7b570a583e20f971b61ee404f8f1aefd9e24ae6a902284e7b51e1bbbe.jpg", + "image_caption": [ + "(a) $z = 1 - \\frac{\\mathbf{x}^{\\mathrm{T}}\\mathbf{y}}{||\\mathbf{x}||||\\mathbf{y}||}$" + ], + "image_footnote": [], + "bbox": [ + 89, + 88, + 339, + 251 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/b6afae9c4b7b9f2ba22ae0b15e703ef6ba7047b34c5ed44aa2745f734392ce7e.jpg", + "image_caption": [ + "(b) $z = \\| \\mathbf{x} - \\mathbf{y}\\|$ , $\\| \\mathbf{y}\\| = 0.2$", + "Figure 2. The measures of two gradient discrepancy from $\\mathbf{x}$ to $\\mathbf{y}$ . Note that the $x$ - and $y$ -axes are the angle (i.e., $\\angle \\mathbf{x}, \\mathbf{y}$ ) between $\\mathbf{x}$ and $\\mathbf{y}$ , and the magnitude ratio $\\frac{\\|\\mathbf{x}\\|}{\\|\\mathbf{y}\\|}$ , respectively. (a) Cosine distance; (b) Euclidean distance where $\\|\\mathbf{y}\\| = 0.2$ as an example; (c) Asymmetric gradient distance. Please see Appendix for the contours." + ], + "image_footnote": [], + "bbox": [ + 357, + 88, + 609, + 252 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/345811336273ba2622e3644d54005241be6d9bbb510a1dd1f32611206276f100.jpg", + "image_caption": [ + "(c) $z = \\frac{\\|\\mathbf{x} - \\mathbf{y}\\|}{\\|\\mathbf{y}\\| + \\|\\mathbf{x} - \\mathbf{y}\\|}$" + ], + "image_footnote": [], + "bbox": [ + 625, + 89, + 870, + 252 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Lemma 1 (Asymmetric Metric [14]) $D:\\mathcal{X}\\times \\mathcal{X}\\to \\mathbb{R}$ is an asymmetric metric (a.k.a. quasi-metric [47]) if $D$ satisfies", + "bbox": [ + 75, + 344, + 468, + 375 + ], + "page_idx": 3 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "(1) $D(\\mathbf{x},\\mathbf{y})\\geq 0$ and $\\forall \\mathbf{x}\\in \\mathbb{R}^d,D(\\mathbf{x},\\mathbf{x}) = 0;$", + "(2) $D(\\mathbf{x},\\mathbf{z})\\leq D(\\mathbf{x},\\mathbf{y}) + D(\\mathbf{y},\\mathbf{z}),\\forall \\mathbf{x},\\mathbf{y},\\mathbf{z}\\in \\mathbb{R}^{d}.$" + ], + "bbox": [ + 76, + 377, + 410, + 409 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The asymmetric metric does not require the symmetric property, i.e., $D(\\mathbf{x}, \\mathbf{y}) = D(\\mathbf{y}, \\mathbf{x})$ . Based on the definition, in this paper, we design an asymmetric metric to measure gradient discrepancy named Asymmetric Gradient Distance.", + "bbox": [ + 75, + 416, + 470, + 477 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Definition 1 (Asymmetric Gradient Distance (AGD))", + "text_level": 1, + "bbox": [ + 75, + 489, + 444, + 503 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Given two gradient $\\mathbf{g}_A$ and $\\mathbf{g}_B$ , the asymmetric gradient distance is defined as", + "bbox": [ + 75, + 505, + 468, + 535 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\widehat {D} (\\mathbf {g} _ {A}, \\mathbf {g} _ {B}) = \\left\\{ \\begin{array}{c l} 0 & , \\quad i f \\mathbf {g} _ {A} = \\mathbf {g} _ {B} = \\mathbf {0}, \\\\ \\frac {\\| \\mathbf {g} _ {A} - \\mathbf {g} _ {B} \\|}{\\| \\mathbf {g} _ {B} \\| + \\| \\mathbf {g} _ {A} - \\mathbf {g} _ {B} \\|}, & O t h e r w i s e. \\end{array} \\right.\n$$\n", + "text_format": "latex", + "bbox": [ + 89, + 546, + 454, + 599 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In Definition 1, we consider the edge situation when $\\mathbf{g}_{\\mathrm{A}} = \\mathbf{g}_{\\mathrm{B}} = \\mathbf{0}$ to meet the definition of the asymmetric metric in Lemma 1. In AGD, gradient directions and magnitudes are considered. Instead of using gradient magnitude value difference, we use magnitude ratio difference to avoid the diverse training of different tasks in PCL. Therefore, we derive the corollary of the magnitude ratio:", + "bbox": [ + 75, + 614, + 468, + 720 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Corollary 1 $\\widehat{D} (\\mathbf{g}_A,\\mathbf{g}_B)$ is an asymmetric metric and holds", + "bbox": [ + 76, + 729, + 467, + 747 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\lim_{\\substack{\\| \\mathbf{g}_{A}\\| \\\\ \\| \\mathbf{g}_{B}\\| \\to \\infty}}\\widehat{D} (\\mathbf{g}_{A},\\mathbf{g}_{B}) = 1,\\quad \\lim_{\\substack{\\| \\mathbf{g}_{A}\\| \\\\ \\| \\mathbf{g}_{B}\\| \\to 0}}\\widehat{D} (\\mathbf{g}_{A},\\mathbf{g}_{B}) = \\frac{1}{2}.\n$$\n", + "text_format": "latex", + "bbox": [ + 104, + 758, + 442, + 795 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We illustrate why AGD is qualified to evaluate the gradient discrepancy according to the definition and corollary. In Definition 1, we use AGD to represent the influence of $\\mathbf{g}_{\\mathrm{A}}$ on task B rather than the inverse. This is the key difference from the symmetric metrics such as Euclidean distance. Specifically, $\\mathbf{g}_{\\mathrm{A}}$ may make task B worse if $\\widehat{D}(\\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}})$ is large (close", + "bbox": [ + 75, + 809, + 470, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "to 1). If $\\widehat{D}(\\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}})$ is close to 0, $\\mathbf{g}_{\\mathrm{A}}$ and $\\mathbf{g}_{\\mathrm{B}}$ has less conflict. Moreover, Corollary 1 involves that when $\\|\\mathbf{g}_{\\mathrm{A}}\\| \\ll \\|\\mathbf{g}_{\\mathrm{B}}\\|$ , AGD has a tolerance $\\frac{1}{2}$ even if $\\langle \\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}} \\rangle < 0$ , which means the impact of $\\mathbf{g}_{\\mathrm{A}}$ on task B is mild. This is because updating with a zero gradient will neither improve nor damage the performance. Even though, we prefer positive influence rather than non-influence. Thus, we define that the distance $\\widehat{D}(\\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}})$ in this situation is the mid-level $(\\frac{1}{2})$ in the value range([0,1]). See different tolerances in our experiments.", + "bbox": [ + 496, + 343, + 893, + 479 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Moreover, we compare AGD (Fig. 2(c)) with Euclidean and cosine distance in Fig. 2. First, the cosine distance (Fig. 2(a)) is magnitude irrelevant, which ignores the magnitude difference in PCL. Second, the Euclidean distance (Fig. 2(b)) depends heavily on the magnitude value difference, but ignores that the gradient influence on the model update is asymmetric. For example, when $\\| \\mathbf{x}\\| \\to 0$ , EuDist will get large if we have large $\\| \\mathbf{y}\\|$ without any tolerance, which ignores the non-influence of zero gradient.", + "bbox": [ + 496, + 479, + 893, + 617 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Maximum Discrepancy Optimization", + "text_level": 1, + "bbox": [ + 500, + 625, + 821, + 642 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "At time $t$ , let the optimal solution to Problem (3) be $\\mathbf{d}^*$ , where $\\mathcal{T}_t$ is the index set of in-training tasks ( $\\mathcal{T}$ for simplicity). However, directly optimizing the problem is difficult due to the large decision space that has the same dimension as $\\pmb{\\theta}$ . Following [28, 40], we use linear scalarization to solve the transformed problem that allows only optimizing decision variable $\\mathbf{w} \\in \\mathbb{R}^{|\\mathcal{T}|}$ . That is, let $\\mathbf{d} = \\sum_{i \\in \\mathcal{T}} \\mathbf{w}_i \\mathbf{g}_i$ , where $\\forall \\mathbf{w}_i \\geq 0$ and $\\sum_{i \\in \\mathcal{T}} \\mathbf{w}_i = 1$ , we have", + "bbox": [ + 496, + 648, + 893, + 771 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {w} ^ {*} = \\underset {\\mathbf {w}} {\\arg \\min } \\quad \\left\\{\\widehat {D} \\left(\\sum_ {j} \\mathbf {w} _ {j} \\mathbf {g} _ {j}, \\mathbf {g} _ {i}\\right) | \\forall i \\in \\mathcal {T} \\right\\}. \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 514, + 781, + 890, + 830 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Each objective of the dual problem will be highly affected by the minimum discrepancy, i.e., each gradient itself. For example, by minimizing objective $\\widehat{D} (\\sum_{j}\\mathbf{w}_{j}\\mathbf{g}_{j},\\mathbf{g}_{i})$ , weight $\\mathbf{w}_i$ is more like to be activated than others. Thus, multiple", + "bbox": [ + 496, + 839, + 893, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "11414", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/86a186d1cdc01e2ac887d2d6f6b1e43f3672b64a687f052eca119106534c96f2.jpg", + "image_caption": [ + "Figure 3. Schematic of Maximum Discrepancy Optimization. Given multiple gradients $\\{\\mathbf{g}_i|\\forall i\\in \\mathcal{T}\\}$ $(|\\mathcal{T}| = 4$ for example) (1) A weight matrix $\\mathbf{W}$ is initialized with $\\frac{1}{|\\mathcal{T}|}$ for each entry. (2) For each row, the off-diagonal entries are used to weighted gradients and optimized for minimum AGD to the target gradient. (3) The diagonal entries $(\\square)$ are used to optimize with min-norm with MGDA. (4) The final weight matrix is reduced by each column for the final weights $(w^{\\prime})$ . See Sec. 3.3 for details." + ], + "image_footnote": [], + "bbox": [ + 78, + 87, + 893, + 282 + ], + "page_idx": 4 + }, + { + "type": "code", + "sub_type": "algorithm", + "code_caption": [ + "Algorithm 1: MaxDO ( ) in PCL" + ], + "code_body": "Input: Parameters $\\theta ,\\theta_{1:T}$ ; Step sizes $\\alpha$ $\\alpha_{1:T}$ Output: $\\theta ,\\theta_{1:T}$ \n1 for t in timeline do \n2 $\\mathcal{T}_t\\gets$ in-training task index; \n3 for $i\\in \\mathcal{T}_t$ do \n4 $\\begin{array}{r}\\mathcal{B}_i\\sim \\mathcal{D}_i;\\\\ \\pmb {\\theta}_i\\gets \\pmb {\\theta}_i - \\alpha_i\\nabla_{\\pmb{\\theta}_i}\\ell_i(\\mathcal{B}_i);\\\\ \\mathbf{g}_i = \\nabla_\\theta \\ell_i(\\mathcal{B}_i); \\end{array}$ \n5 \n6 end \n7 W\\* Optimization by Eq. (5); d\\* Final graident from Eq. (6); \n8 \n9 $\\theta \\leftarrow \\theta -\\alpha \\mathbf{d}^{*};$", + "bbox": [ + 81, + 388, + 436, + 593 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "objectives will be compromised by multiple self-interference but fail to reduce the maximum discrepancy in the dual problem optimization.", + "bbox": [ + 75, + 631, + 468, + 676 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "As shown in Fig. 3, we propose Maximum Discrepancy Optimization (MaxDO) to reduce the maximum gradient discrepancy. Specifically, instead of the weight vector $\\mathbf{w} \\in \\mathbb{R}^{|\\mathcal{T}|}$ , we optimize a weight matrix $\\mathbf{W} \\in \\mathbb{R}^{|\\mathcal{T}| \\times |\\mathcal{T}|}$ in which $\\forall \\mathbf{W}_{ij} \\geq 0$ . $\\mathbf{W}$ can be combined by a diagonal vector $\\dot{\\mathbf{w}} = [\\mathbf{W}_{1,1}, \\dots, \\mathbf{W}_{|\\mathcal{T}|,|\\mathcal{T}|}]$ and an off-diagonal matrix $\\widetilde{\\mathbf{W}} = \\mathbf{W} - \\mathrm{Diag}(\\dot{\\mathbf{w}})$ , where $\\sum_{i \\in \\mathcal{T}} \\dot{\\mathbf{w}}_i = 1$ and $\\sum_{j \\in \\mathcal{T}} \\widetilde{\\mathbf{W}}_{ij} = 1, \\forall i$ . Thus, $\\sum_{i,j \\in \\mathcal{T}} \\mathbf{W}_{ij} = |\\mathcal{T}| + 1$ and the two weights are independent and can be optimized without disturbance as follows: (1) $\\widetilde{\\mathbf{W}}$ , computed by Stochastic Gradient Descent (SGD), is used to make up the maximum gradient discrepancy. The objectives of any two rows in $\\widetilde{\\mathbf{W}}$ are different. For row $i$ , to formulate the maximum discrepancy of gradient $\\mathbf{g}_i$ , the objective is the combina", + "bbox": [ + 75, + 679, + 472, + 901 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "tion of non-diagonal entries. The weighted other gradients should be with the smallest asymmetric distance to $\\mathbf{g}_i$ . (2) $\\dot{\\mathbf{w}}$ is obtained by the Multiple Gradient Descent Algorithm (MGDA) [15], which is to obtain a weighted gradient that does not damage any tasks with a min-norm optimization. The objective of MGDA is 0 and the resulting point satisfies the Karush-Kuhn-Tucker condition or the solution gives a Pareto descent direction that improves all tasks. See Appendix for more details of MGDA. For each off-diagonal entry of the $i$ -th column, their sum means the effect of the gradient $\\mathbf{g}_i$ reducing the maximum discrepancy from other gradients. MGDA is used to reduce the possible negative effect in MaxDO. On the other hand, MaxDO reduces the training failure of new tasks in MGDA. To sum up, our MaxDO with AGD can be computed by", + "bbox": [ + 496, + 368, + 895, + 597 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {W} ^ {*} = \\underbrace {\\arg \\min _ {\\widetilde {\\mathbf {W}}} \\sum_ {\\forall i \\in \\mathcal {T}} \\widehat {D} \\left(\\sum_ {j \\neq i} \\widetilde {\\mathbf {W}} _ {i , j} \\mathbf {g} _ {j} , \\mathbf {g} _ {i}\\right)} _ {\\text {S G D w i t h M a x i m u m D i s c r e p a n c y}} + \\operatorname {D i a g} \\underbrace {\\left(\\underset {\\dot {\\mathbf {w}}} {\\arg \\min } \\left\\| \\sum_ {j} \\dot {\\mathbf {w}} _ {j} \\mathbf {g} _ {j} \\right\\|\\right)} _ {\\text {M G D A [ 1 5 ]}}. \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 550, + 602, + 893, + 741 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In Eq. (5), we can obtain an approximate solution by combining the closed-form solution and the iterative solution. Fig. 3 reveals the diagram of solving MaxDO. We project the solution of SGD onto the feasible set $(\\sum_{i \\neq j} \\mathbf{W}_{ij} = 1)$ via softmax at each step in the multiple steps for fast convergence. First, we initialize all entries of $\\mathbf{W}$ by $\\frac{1}{|\\mathcal{T}|}$ . Then, the off-diagonal matrix is used to minimize the maximum gradient discrepancy via SGD and the diagonal vector is optimized by min-norm. Finally, the final weights are reduced to a vector by dividing $|\\mathcal{T}| + 1$ to guarantee that their sum", + "bbox": [ + 496, + 747, + 895, + 902 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "11415", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "is 1. Note that, MaxDO is implemented only when $|\\mathcal{T}| > 1$ , i.e., multiple tasks are given at the current time. Otherwise, we have $\\mathbf{d}^{*} = \\mathbf{g}_{1}$ for the only current task 1. Thus, the final gradient $\\mathbf{d}^{*}$ is computed by", + "bbox": [ + 75, + 90, + 470, + 154 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {d} ^ {*} = \\left\\{ \\begin{array}{l l} \\mathbf {g} _ {1}, & | \\mathcal {T} | = 1, \\\\ \\sum_ {i} \\left(\\frac {1}{| \\mathcal {T} | + 1} \\sum_ {j} \\mathbf {W} _ {j, i} ^ {*}\\right) \\mathbf {g} _ {i}, & | \\mathcal {T} | > 1. \\end{array} \\right. \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 96, + 162, + 468, + 232 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The detailed algorithm is shown in Algorithm 1. With the rehearsal data stream, our algorithm learns a PCL model through a timeline. At the time $t$ on the timeline, given a mini-batch $\\mathcal{B}$ from each data stream, we compute the corresponding gradients on shared and task-specific parameters. The task-specific parameters are updated directly and the gradients on the shared backbone are collected for computed the final updated gradient $\\mathbf{d}$ . By using our MaxDO, we update the shared parameters $\\theta$ with the optimal $\\mathbf{d}^*$ .", + "bbox": [ + 75, + 242, + 472, + 380 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiment", + "text_level": 1, + "bbox": [ + 76, + 393, + 202, + 411 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Dataset", + "text_level": 1, + "bbox": [ + 76, + 417, + 174, + 434 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In our experiments, 3 traditional image recognition datasets are transformed into parallel data streams: (1) Parallel Split EMNIST (PS-EMNIST). We split EMNIST [13] (62 classes) into 5 tasks and the size of the label set for each task, i.e., the number of classes, is set to \\{12, 12, 12, 13, 13\\}. (2) Parallel Split CIFAR-100 (PS-CIFAR-100). We split CIFAR-100 into 10 tasks and the size of the label set for each task is set to 10. (3) Parallel Split ImageNet-TINY (PS-ImageNet-TINY). We split Tiny ImageNet [26] (200 classes) into 10 tasks, and the size of the label set for each task is set to 20. We evaluate PCL on task-incremental and class-incremental scenarios. Please see Appendix for more dataset details.", + "bbox": [ + 75, + 441, + 472, + 623 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "All three datasets have 3 different label sets (3 different class splits), each of which has 3 different timelines (when to access). For each timeline, we have 3 different runs with fixed seeds 1234, 1235, and 1236 for parameter initialization. In other words, we have 27 different settings for each dataset, and we report the average and standard deviation (avg $\\pm$ std) for each compared method in our experiments. Note that, we omit all blank time that no data stream flows for simplicity.", + "bbox": [ + 75, + 625, + 470, + 747 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Experiment Details", + "text_level": 1, + "bbox": [ + 76, + 756, + 264, + 772 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We implement our experiments using Tensorflow and conduct on a single NVidia RTX 3090Ti GPU card. We take a 2-layer MLP as the backbone network for PS-EMNIST and a Resnet-18 [22] for PS-CIFAR-100 and PS-ImageNet-Tiny. The learning rate is set to 0.003, 0.0004 and 0.0005 for PS-EMNIST, PS-CIFAR-100 and PS-ImageNet-Tiny. The SGD in MaxDO has a learning rate of 5. Each task is trained in a data stream, i.e., each data point passes only once. For each", + "bbox": [ + 75, + 779, + 472, + 902 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/1ae8de300461d0b1ceda8b92b66ef17a7b1dd0cee77b568ac8ba6ba7f66e7f75.jpg", + "image_caption": [ + "Figure 4. Different memory sizes on PS-CIFAR-100." + ], + "image_footnote": [], + "bbox": [ + 500, + 93, + 696, + 234 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/4fff1c78cc545be1a217d1ffa6e29e7ae4fbebcde1ad6dcbb68e42c55236c811.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 696, + 93, + 885, + 234 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "task, we set the batch size to 128 per step. For any new task in PCL, we build a new classifier, which is a fully-connected layer with a softmax function.", + "bbox": [ + 496, + 277, + 890, + 321 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To evaluate PCL, we compute the average accuracy and forgetting, following previous continual learning studies [31, 9, 3, 2, 37]. Let $e_t$ be the end time of task $t$ and the final time $\\bar{e} = \\max(e_1, e_2, \\dots, e_T)$ , the two metrics are computed as:", + "bbox": [ + 496, + 323, + 893, + 385 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\nA _ {\\bar {e}} = \\frac {1}{T} \\sum_ {t = 1} ^ {T} a _ {\\bar {e}} ^ {t}, \\quad F _ {\\bar {e}} = \\frac {1}{T} \\sum_ {t = 1} ^ {T} a _ {\\bar {e}} ^ {t} - a _ {e _ {t}} ^ {t}, \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 557, + 393, + 890, + 436 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $a_{k}^{j}$ is the mean testing accuracy of task $j$ at time $k$ . $A_{\\bar{e}}$ denotes the final average accuracy on all the tasks, and $F_{\\bar{e}}$ (also known as backward transfer) means the final performance drop compared to each task that was first trained.", + "bbox": [ + 498, + 444, + 893, + 506 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Main Results", + "text_level": 1, + "bbox": [ + 500, + 513, + 638, + 529 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We compare our method with MTL methods including MGDA [15], GradNorm [11], DWA [30], GradDrop [12], PCGrad [50] and RLW [28] in the PCL setting. We treat any time on the timeline as an MTL subunit to train PCL. All results of previous MTL methods are produced by ourselves with the claimed design in their papers. We also compare with some rehearsal-based SCL methods including AGEM[9], GMED[37] and ER[10]. To adapt to the SCL methods, we merge batches from every in-training task to mimic a naive sequence learning that only a batch from the current task and a batch from the memory buffer.", + "bbox": [ + 496, + 537, + 893, + 703 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We show the main comparisons with the proposed methods in Tables 1 and 2 on the three datasets. We have several major observations. First, the rehearsal strategy is useful for reducing catastrophic forgetting in PCL for all compared methods. As an extra data stream apart from in-training data streams, rehearsal provides data from the finished tasks training together with other tasks to suppress forgetting. With the rehearsal strategy, the memory may provide continual learning of finished tasks, and even better performance can be obtained, which results in positive forgetting values on $F_{\\bar{e}}$ . Second, without task-id, class-incremental PCL has worse performance than task-incremental PCL. Surprisingly, we find that MGDA has good performance than other methods in", + "bbox": [ + 496, + 704, + 895, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "11416", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/cea4a168931b6ecf7be8859b4b087d1b3274312d72ccb7268287f0325a47f23c.jpg", + "table_caption": [ + "Table 1. Task-incremental comparisons (avg ± std) on 3 datasets." + ], + "table_footnote": [], + "table_body": "
Method (+ Reherasal)TypePS-EMNISTPS-CIFAR-100PS-ImageNet-TINY
A̅̅ (‰)F̅̅ (‰)A̅̅ (‰)F̅̅ (‰)A̅̅ (‰)F̅̅ (‰)
AvgGradMTL89.344 ± 0.231-5.287 ± 0.21647.579 ± 0.08923.691 ± 0.43238.392 ± 0.0760.764 ± 0.139
MGDA [15]MTL84.887 ± 0.469-4.301 ± 0.81848.957 ± 0.45125.088 ± 0.20338.058 ± 0.7401.465 ± 0.490
GradNorm [11]MTL87.888 ± 0.158-6.197 ± 0.18347.210 ± 1.32323.474 ± 0.68838.226 ± 0.7691.647 ± 0.667
DWA [30]MTL88.405 ± 0.322-5.452 ± 0.33844.969 ± 0.37822.682 ± 0.53734.290 ± 1.099-1.053 ± 0.866
PCGrad [50]MTL89.698 ± 0.164-4.921 ± 0.12147.026 ± 0.53823.244 ± 0.74039.427 ± 1.2752.017 ± 0.769
RLW [28]MTL89.288 ± 0.218-5.226 ± 0.20447.574 ± 0.34923.833 ± 0.11738.531 ± 1.6101.332 ± 1.148
AGEM [9]SCL87.022 ± 0.519-7.646 ± 0.48327.379 ± 0.5855.416 ± 0.85128.530 ± 0.994-7.070 ± 1.410
GMED [37]SCL85.471 ± 0.324-8.875 ± 0.33549.094 ± 1.79218.356 ± 1.34534.495 ± 1.568-0.640 ± 1.799
ER [10]SCL89.106 ± 0.315-5.525 ± 0.20747.324 ± 0.58423.330 ± 0.76235.950 ± 0.763-0.767 ± 0.591
MaxDO (AGD)PCL90.189 ± 0.314-4.258 ± 0.31150.203 ± 0.97824.510 ± 0.09240.770 ± 0.3543.119 ± 0.450
", + "bbox": [ + 81, + 101, + 893, + 284 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/feb92a33b6857604b56a3444d1dafb174b1d163dcf05e30ac3b7b7e21f886eee.jpg", + "table_caption": [ + "Table 2. Class-incremental comparisons (avg $\\pm$ std) on 3 datasets." + ], + "table_footnote": [], + "table_body": "
Method (+ Reherasal)TypePS-EMNISTPS-CIFAR-100PS-ImageNet-TINY
A̅e(%)F̅e(%)A̅e(%)F̅e(%)A̅e(%)F̅e(%)
AvgGradMTL43.823 ± 0.566-44.484 ± 0.5968.921 ± 0.276-4.985 ± 0.7027.511 ± 0.661-15.825 ± 0.228
MGDA [15]MTL52.823 ± 0.201-7.753 ± 0.53811.323 ± 0.282-4.065 ± 0.7258.318 ± 0.155-13.118 ± 0.739
GradNorm [11]MTL43.292 ± 0.590-44.824 ± 0.6889.477 ± 0.222-4.403 ± 1.2366.395 ± 0.130-15.869 ± 0.336
DWA [30]MTL42.734 ± 0.211-38.944 ± 0.5813.519 ± 0.116-7.470 ± 0.2443.003 ± 0.139-12.774 ± 0.158
PCGrad [50]MTL45.035 ± 0.273-43.309 ± 0.17610.140 ± 0.253-5.149 ± 0.5537.789 ± 0.237-15.860 ± 0.318
RLW [28]MTL44.595 ± 0.480-43.424 ± 0.3259.957 ± 0.135-5.173 ± 0.6137.419 ± 0.258-16.079 ± 0.255
AGEM [9]SCL26.249 ± 0.511-62.480 ± 0.5273.374 ± 0.098-10.462 ± 0.5433.379 ± 0.149-18.514 ± 0.516
GMED [37]SCL22.694 ± 0.153-65.805 ± 0.2554.941 ± 0.407-12.837 ± 0.7103.386 ± 0.348-19.060 ± 0.682
ER [10]SCL43.474 ± 0.860-44.597 ± 0.8619.317 ± 0.339-5.337 ± 0.6266.126 ± 0.277-13.686 ± 0.290
MaxDO (AGD)PCL53.139 ± 0.156-11.903 ± 0.47612.237 ± 0.176-2.280 ± 0.2709.532 ± 0.363-12.511 ± 0.610
", + "bbox": [ + 81, + 310, + 890, + 489 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "class-incremental PCL compared with the task-incremental scenario, which means the suppressing on catastrophic forgetting is more important in class-incremental PCL. Third, the compared MTL methods are designed for balanced training and ignore the diverse training process in PCL, thus some gradients may be counteracted because of the large gradient discrepancy when updating the model. In contrast, our MaxDO with AGD obtains the best final accuracy $A^T$ on three datasets and two scenarios, which shows our superiority in balancing plasticity and stability. For example, we have $40.770\\%$ and $9.431\\%$ for PS-ImageNet-TINY on two scenarios respectively, while the compared best value is only $39.427\\%$ and $8.318\\%$ . On one hand, the proposed AGD is used to measure the asymmetric distance between gradients to boost the effective update of each task. On the other hand, the maximum discrepancies between multiple tasks are reduced. Note that, the forgetting measure of the proposed methods may not outperform the compared methods because we got both better new tasks and final accuracy performance, their difference value may be small.", + "bbox": [ + 76, + 517, + 473, + 819 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4. Rehearsal Analysis in PCL", + "text_level": 1, + "bbox": [ + 76, + 830, + 318, + 847 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In Fig. 4, we compare the effects of different memory buffer sizes (per class) in rehearsal on PS-CIFAR-100. We observe that the memory buffer size affects the remembering", + "bbox": [ + 76, + 854, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "of old knowledge, and a larger size means better knowledge keeping, which is similar to traditional CL. Under the same memory size, our method has better performance. Then, in Table 3(a), to show the MaxDO's effectiveness of forgetting reduction on rehearsal gradient, we evaluate the result that only leverages MaxDO on new tasks. In this case, the final gradient is calculated by $\\mathbf{d} = \\frac{1}{2}\\mathbf{g}_{\\mathrm{reh}} + \\frac{1}{2}\\mathbf{g}_{\\mathrm{new}}$ , where $\\mathbf{g}_{\\mathrm{new}}$ is the solution gradient via MaxDO on only new parallel tasks, and $\\mathbf{g}_{\\mathrm{reh}}$ means the gradient from the rehearsal data streams. The result shows that it is necessary to put the rehearsal gradient to the MaxDO. Otherwise, the model will get worse accuracy and forgetting.", + "bbox": [ + 496, + 517, + 893, + 700 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.5. Comparison with Symmetric Metrics", + "text_level": 1, + "bbox": [ + 500, + 708, + 821, + 724 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "As shown in Table 3(b), we compare AGD with three common symmetric metrics including EuDist, CosDist, and Normalized EuDist. EuDist, CosDist are defined in Sec. 3.2. The vanilla EuDist depends highly on the gradient magnitude difference, thus we also compare with its normalized version $D(\\mathbf{x},\\mathbf{y}) = \\frac{\\|\\mathbf{x} - \\mathbf{y}\\|}{\\|\\mathbf{x}\\| + \\|\\mathbf{y}\\|} \\in [0,1]$ , namely normalized EuDist (Norm EuDist). The results show that the three metrics can also obtain good performance with MaxDO. However, EuDist fails to reduce catastrophic forgetting effectively because of the over-emphasizing of gradient magnitude difference. Considering only the gradient direction difference, MaxDO", + "bbox": [ + 496, + 731, + 893, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "11417", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/7b850b10ace0dbe2f8465249c04865d9b9bc185f2b83a2a8cfccc6368cee695e.jpg", + "table_caption": [ + "Table 3. Reherasal experiemtns, comparisons with symmetric metrics and ablation studies in MaxDO on PS-CIFAR-100." + ], + "table_footnote": [], + "table_body": "
ExperimentMethodTask-incrementClass-increment
A̅e(%)F̅e(%)A̅e(%)F̅e(%)
(a) Rehearsal analysisMaxDO (w/o Rehearsal)25.241 ± 0.4663.128 ± 0.1752.971 ± 0.048-11.356 ± 0.703
MaxDO (w/o Reheerasal gradient)47.653 ± 1.28023.538 ± 1.4689.431 ± 0.469-5.907 ± 0.658
(b) Symmetric metricsMaxDO (EuDist)49.201 ± 0.41024.112 ± 0.19710.189 ± 0.218-7.172 ± 0.796
MaxDO (CosDist)49.154 ± 0.57025.094 ± 0.22211.771 ± 0.139-3.114 ± 0.681
MaxDO (Norm EuDist)48.517 ± 0.33624.386 ± 0.38811.692 ± 0.373-3.228 ± 0.822
(c) Ablation studiesMGDA [15]48.957 ± 0.45125.088 ± 0.20311.323 ± 0.282-4.065 ± 0.725
MaxDO (w/o Max-Discrepancy)47.899 ± 1.02223.874 ± 0.44710.441 ± 0.324-4.807 ± 0.573
MaxDO (w/o MGDA)49.631 ± 0.43125.816 ± 0.56111.881 ± 0.468-2.993 ± 0.964
(d) Our full methodMaxDO (AGD, w/ Reherasal)50.203 ± 0.27424.510 ± 0.09212.237 ± 0.176-2.280 ± 0.270
", + "bbox": [ + 81, + 101, + 893, + 280 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/18d9405b8087426dcf15d0ca9fea6a247f6b347f5598f8ac4f42496dba9479d9.jpg", + "image_caption": [ + "(a)", + "Figure 5. Training time comparisons." + ], + "image_footnote": [], + "bbox": [ + 78, + 308, + 271, + 445 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/5197341081d95afd38ac43bf1b27e759b29e2e5cba2c6a875248ef209fac8e1d.jpg", + "image_caption": [ + "(b)" + ], + "image_footnote": [], + "bbox": [ + 272, + 306, + 464, + 445 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "with CosDist obtains better performance than EuDist. But CosDist ignores the magnitude difference, which is also important in the min-distance problem, resulting in insufficient performance. Compared to EuDist, normalized EuDist obtains even worse performance. In contrast, MaxDO with AGD considers the asymmetric influence on gradient update, and tolerance is set to reduce the influence from small gradients to new-access tasks, which yields the best performance.", + "bbox": [ + 75, + 503, + 470, + 626 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.6. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 635, + 230, + 651 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We evaluate the impact of the two main components of MaxDO in Table 3(c). First, we block the maximum discrepancy in MaxDO (MaxDO (w/o Max-Discrepancy)), which means that we solve the min-distance problem with Eq. (4) directly. Because of the self-interference, the solution combines the minimum discrepancy but fails to effectively reduce the discrepancy from other gradients (47.899% and 10.441% for $A_{\\bar{e}}$ ). We then block the MGDA that obtains a weighted gradient not damage any tasks. MGDA is quite useful in traditional MTL tasks but is not suitable in PCL (w/o MGDA, 49.693% and 11.881% for $A_{\\bar{e}}$ ). Because of the diverse training process of parallel tasks, gradients are with large magnitude differences and MGDA prefers to set large factors to small gradients. We solve the problem by both MGDA and the maximum discrepancy, and the whole MaxDO method with AGD outperforms the two ablated", + "bbox": [ + 75, + 659, + 472, + 900 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "methods (50.203% and 12.231% for $A_{\\bar{e}}$ ), where the characters of the two components are combined.", + "bbox": [ + 496, + 305, + 893, + 335 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.7. Procedure Time", + "text_level": 1, + "bbox": [ + 498, + 342, + 661, + 357 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In Fig. 5, we show the training time comparison on PS-CIFAR-100. We first compare the training time for 2 to 5 parallel tasks in one iteration (Fig. 5(a)). We find that the generation of task numbers will grow the training time, and MaxDO needs more time than other methods because multiple minimum distance optimizations are performed. Then, we show both the final accuracy and whole training time in Fig. 5(b). In the whole timeline, MaxDO gets slightly longer training time than other methods but better performance.", + "bbox": [ + 496, + 366, + 893, + 502 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.8. Tolerance Analysis in AGD", + "text_level": 1, + "bbox": [ + 498, + 508, + 745, + 525 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In our paper, AGD is designed to have a tolerance $\\frac{1}{2}$ in Corollary 1. This is because updating with a zero gradient will neither improve nor damage the performance. Even though, we prefer positive influence rather than noninfluence. Thus, we define that the distance $\\widehat{D}(\\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}})$ in the situation $\\|\\mathbf{g}_{\\mathrm{A}}\\| \\ll \\|\\mathbf{g}_{\\mathrm{B}}\\|$ is the mid-level in the value range. Therefore, we study to change the tolerance and observe the performance change. The tolerance can be controlled by adding a factor $\\gamma > 0$ at the denominator. Omitting the edge situation, we have", + "bbox": [ + 496, + 532, + 893, + 683 + ], + "page_idx": 7 + }, + { + "type": "equation", + "text": "\n$$\n\\widehat {D} _ {\\gamma} \\left(\\mathbf {g} _ {\\mathrm {A}}, \\mathbf {g} _ {\\mathrm {B}}\\right) = \\frac {\\| \\mathbf {g} _ {\\mathrm {A}} - \\mathbf {g} _ {\\mathrm {B}} \\|}{\\gamma \\| \\mathbf {g} _ {\\mathrm {B}} \\| + \\| \\mathbf {g} _ {\\mathrm {A}} - \\mathbf {g} _ {\\mathrm {B}} \\Vert}.\n$$\n", + "text_format": "latex", + "bbox": [ + 570, + 689, + 821, + 722 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "The experiments on different tolerances are shown in Table 4. The results show either larger or smaller tolerances compared to $\\frac{1}{2}$ will get the performance drop during the PCL training.", + "bbox": [ + 496, + 727, + 893, + 773 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 784, + 619, + 799 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this paper, we studied to address the training conflict and catastrophic forgetting issues in Parallel Continual Learning (PCL). We presented that the two issues are rooted in the gradient discrepancies and formulated the problem into a minimum distance optimization among gradients. However, the distance metric is often set to be symmetric, which", + "bbox": [ + 496, + 810, + 893, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "11418", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/145f50b6952e5e9e748076c39565d82e6f7dae3e74891d7fe7eabdb1415d0ec7.jpg", + "table_caption": [ + "Table 4. Comparisons on different tolerance (Tol.)." + ], + "table_footnote": [], + "table_body": "
γTol.Task-incrementClass-increment
A̅e(%)F̅e(%)A̅e(%)F̅e(%)
0.25/646.118 ± 0.46322.617 ± 0.48411.283 ± 0.696-3.158 ± 1.087
0.52/346.452 ± 0.11322.874 ± 0.68011.284 ± 0.343-3.305 ± 0.629
11/250.203 ± 0.27424.510 ± 0.09212.237 ± 0.176-2.280 ± 0.270
21/349.827 ± 0.42025.520 ± 0.61111.603 ± 0.506-3.503 ± 0.687
31/448.766 ± 0.17124.491 ± 0.40611.389 ± 0.738-3.234 ± 1.060
41/548.859 ± 0.62724.714 ± 0.43711.378 ± 0.484-3.189 ± 0.902
", + "bbox": [ + 81, + 101, + 468, + 191 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "is problematic in gradient descent. To evaluate the gradient discrepancy in PCL, we proposed an explicit Asymmetric Gradient Distance (AGD), which considers both gradient magnitude ratios and directions and has a tolerance when updating with a small gradient of inverse direction. Moreover, we proposed a novel Maximum Discrepancy Optimization (MaxDO) strategy to minimize the maximum discrepancy among multiple gradients and avoid self-interference. Solving by MaxDO with AGD, the parallel training in PCL reduces the influence of the training conflict and slows the catastrophic forgetting. We verified the proposed method on three image recognition datasets. The experimental results significantly showed the advantage of MaxDO and the effectiveness of the proposed AGD. We list the latent limitation of our method: (1) The MaxDO cannot guarantee a theoretical Pareto optimum in the training process like MGDA, which means a better trade-off can be obtained in the future. (2) The MaxDO method needs more time for training.", + "bbox": [ + 76, + 222, + 473, + 494 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement", + "text_level": 1, + "bbox": [ + 76, + 513, + 236, + 531 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We gratefully acknowledge the invaluable support from the following funding bodies: the National Natural Science Foundation of China (62072334, 62276182), and the National Key Research and Development Program of China (2020YFC1522701).", + "bbox": [ + 76, + 542, + 470, + 617 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 637, + 174, + 652 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Rahaf Aljundi, Francesca Babiloni, Mohamed Elhoseiny, Marcus Rohrbach, and Tinne Tuytelaars. Memory aware synapses: Learning what (not) to forget. In ECCV, 2018. 1, 2", + "[2] Rahaf Aljundi, Eugene Belilovsky, Tinne Tuytelaars, Laurent Charlin, Massimo Caccia, Min Lin, and Lucas Page-Caccia. Online continual learning with maximal interfered retrieval. In NeurIPS, 2019. 6", + "[3] Rahaf Aljundi, Min Lin, Baptiste Goujaud, and Yoshua Bengio. Gradient based sample selection for online continual learning. In NeurlPS, 2019. 6", + "[4] Craig Atkinson, Brendan McCane, Lech Szymanski, and Anthony Robins. Pseudo-rehearsal: Achieving deep reinforcement learning without catastrophic forgetting. arXiv preprint arXiv:1812.02464, 2018. 1, 2, 3", + "[5] Aviad Barzilai and Koby Crammer. Convex multi-task learning by clustering. In AISTATS, 2015. 2" + ], + "bbox": [ + 84, + 664, + 470, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[6] Francesca Cagliari, Barbara Di Fabio, and Claudia Landi. The natural pseudo-distance as a quotient pseudo-metric, and applications. In Forum Mathematicum. De Gruyter, 2015. 3", + "[7] Rich Caruana. Multitask learning. Machine learning, 1997. 2", + "[8] Arslan Chaudhry, Puneet K Dokania, Thalaiyasingam Ajthan, and Philip HS Torr. Riemannian walk for incremental learning: Understanding forgetting and intransigence. In ECCV, 2018. 1, 2", + "[9] Arslan Chaudhry, Marc'Aurelio Ranzato, Marcus Rohrbach, and Mohamed Elhoseiny. Efficient lifelong learning with a-gem. In ICLR, 2019. 1, 2, 3, 6, 7", + "[10] Arslan Chaudhry, Marcus Rohrbach, Mohamed Elhoseiny, Thalaiyasingam Ajanthan, Puneet K Dokania, Philip H S Torr, and Marcurelio Ranzato. On tiny episodic memories in continual learning. arXiv: Learning, 2019. 6, 7", + "[11] Zhao Chen, Vijay Badrinarayanan, Chen-Yu Lee, and Andrew Rabinovich. Gradnorm: Gradient normalization for adaptive loss balancing in deep multitask networks. In ICML, 2018. 2, 6, 7", + "[12] Zhao Chen, Jiquan Ngiam, Yanping Huang, Thang Luong, Henrik Kretzschmar, Yuning Chai, and Dragomir Anguelov. Just pick a sign: Optimizing deep multitask models with gradient sign dropout. In NeurIPS, 2020. 2, 6", + "[13] Gregory Cohen, Saeed Afshar, Jonathan Tapson, and Andre Van Schaik. Emmist: Extending mnist to handwritten letters. In IJCNN, 2017. 6", + "[14] Julia Collins and Johannes Zimmer. An asymmetric arzelà-ascoli theorem. Topology and its Applications, 2007. 3, 4", + "[15] Jean-Antoine Désideri. Multiple-gradient descent algorithm (mgda) for multiobjective optimization. Comptes Rendus Mathematique, 2012. 5, 6, 7, 8", + "[16] Prithviraj Dhar, Rajat Vikram Singh, Kuan-Chuan Peng, Ziyan Wu, and Rama Chellappa. Learning without memorizing. In CVPR, 2019. 1, 2", + "[17] Mehrdad Farajtabar, Navig Azizan, Alex Mott, and Ang Li. Orthogonal gradient descent for continual learning. In AISTATS, 2020. 2", + "[18] MA Fiol. On pseudo-distance-regularity. Linear Algebra and its Applications, 2001. 3", + "[19] Robert M French. Catastrophic forgetting in connectionist networks. TiCS, 1999. 1", + "[20] Rick Groenendijk, Sezer Karaoglu, Theo Gevers, and Thomas Mensink. Multi-loss weighting with coefficient of variations. In WACV, 2021. 2", + "[21] Yunhui Guo, Mingrui Liu, Tianbao Yang, and Tajana Rosing. Learning with long-term remembering: Following the lead of mixed stochastic gradient. arXiv preprint arXiv:1909.11763, 2019. 1, 2, 3", + "[22] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, 2016. 6", + "[23] Ali Jalali, Sujay Sanghavi, Chao Ruan, and Pradeep Ravikumar. A dirty model for multi-task learning. In NeurIPS, 2010. 2", + "[24] Adrián Javaloy and Isabel Valera. Rotograd: Gradient homogenization in multitask learning. arXiv preprint arXiv:2103.02631, 2021. 2" + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "11419", + "bbox": [ + 478, + 944, + 519, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[25] James Kirkpatrick, Razvan Pascanu, Neil Rabinowitz, Joel Veness, Guillaume Desjardins, Andrei A Rusu, Kieran Milan, John Quan, Tiago Ramalho, Agnieszka Grabska-Barwinska, et al. Overcoming catastrophic forgetting in neural networks. PNAS, 2017. 1, 2", + "[26] Ya Le and Xuan Yang. Tiny imagenet visual recognition challenge. CS 231N, 2015. 6", + "[27] Zhizhong Li and Derek Hoiem. Learning without forgetting. TPAMI, 2017. 1", + "[28] Baijiong Lin, Feiyang Ye, and Yu Zhang. A closer look at loss weighting in multi-task learning. arXiv preprint arXiv:2111.10603, 2021. 2, 4, 6, 7", + "[29] Bo Liu, Xingchao Liu, Xiaojie Jin, Peter Stone, and Qiang Liu. Conflict-averse gradient descent for multi-task learning. In NeurIPS, 2021. 2", + "[30] Shikun Liu, Edward Johns, and Andrew J Davison. End-to-end multi-task learning with attention. In CVPR, 2019. 2, 6, 7", + "[31] David Lopez-Paz and Marc'Aurelio Ranzato. Gradient episodic memory for continual learning. In NeurIPS, 2017. 1, 2, 3, 6", + "[32] Fan Lyu, Shuai Wang, Wei Feng, Zihan Ye, Fuyuan Hu, and Song Wang. Multi-domain multi-task rehearsal for lifelong learning. In AAAI, 2021. 2", + "[33] Arun Mallya, Dillon Davis, and Svetlana Lazebnik. Piggyback: Adapting a single network to multiple tasks by learning to mask weights. In ECCV, 2018. 1, 2", + "[34] Andreas Maurer, Massi Pontil, and Bernardino Romero-Paredes. Sparse coding for multitask and transfer learning. In ICML, 2013. 2", + "[35] Andrea CG Mennucci. On asymmetric distances. Analysis and Geometry in Metric Spaces, 2013. 3", + "[36] Jary Pomponi, Simone Scardapane, and Aurelio Uncini. Pseudo-rehearsal for continual learning with normalizing flows. arXiv preprint arXiv:2007.02443, 2020. 1, 2, 3", + "[37] Liu Risheng, Liu Yaohua, Zeng Shangzhi, and Jin Zhang. Gradient-based editing of memory examples for online task-free continual learning. In NeurIPS, 2021. 6, 7", + "[38] Amir Rosenfeld and John K Tsotsos. Incremental learning through deep adaptation. TPAMI, 2018. 1, 2", + "[39] Andrei A Rusu, Neil C Rabinowitz, Guillaume Desjardins, Hubert Soyer, James Kirkpatrick, Koray Kavukcuoglu, Razvan Pascanu, and Raia Hadsell. Progressive neural networks. arXiv preprint arXiv:1606.04671, 2016. 1, 2", + "[40] Ozan Sener and Vladlen Koltun. Multi-task learning as multi-objective optimization. In NeurIPS, 2018. 2, 4", + "[41] Haseeb Shah, Khurram Javed, and Faisal Shafait. Distillation techniques for pseudo-rehearsal based incremental learning. arXiv preprint arXiv:1807.02799, 2018. 1, 2, 3", + "[42] Donald Shenaj, Marco Toldo, Alberto Rigon, and Pietro Zanuttigh. Asynchronous federated continual learning. In CVPR, 2023. 3", + "[43] Qing Sun, Fan Lyu, Fanhua Shang, Wei Feng, and Liang Wan. Exploring example influence in continual learning. *NeurIPS*, 2022. 1", + "[44] Sebastian Thrun and Joseph O'Sullivan. Discovering structure in multiple learning tasks: The tc algorithm. In ICML, 1996. 2" + ], + "bbox": [ + 78, + 90, + 470, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[45] Jie Wang and Jieping Ye. Safe screening for multi-task feature learning with multiple data matrices. In ICML, 2015. 2", + "[46] Zirui Wang, Yulia Tsvetkov, Orhan Firat, and Yuan Cao. Gradient vaccine: Investigating and improving multi-task optimization in massively multilingual models. arXiv preprint arXiv:2010.05874, 2020. 2", + "[47] Wallace Alvin Wilson. On quasi-metric spaces. American Journal of Mathematics, 1931. 4", + "[48] Jaehong Yoon, Wonyong Jeong, Giwoong Lee, Eunho Yang, and Sung Ju Hwang. Federated continual learning with weighted inter-client transfer. In ICML, 2021. 3", + "[49] Jaehong Yoon, Eunho Yang, Jeongtae Lee, and Sung Ju Hwang. Lifelong learning with dynamically expandable networks. arXiv preprint arXiv:1708.01547, 2017. 1, 2", + "[50] Tianhe Yu, Saurabh Kumar, Abhishek Gupta, Sergey Levine, Karol Hausman, and Chelsea Finn. Gradient surgery for multi-task learning. In NeurIPS, 2020. 1, 2, 3, 6, 7", + "[51] Friedemann Zenke, Ben Poole, and Surya Ganguli. Continual learning through synaptic intelligence. In ICML, 2017. 1, 2", + "[52] Yu Zhang and Qiang Yang. A survey on multi-task learning. IEEE TKDE, 2021. 2" + ], + "bbox": [ + 501, + 90, + 893, + 391 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "11420", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/e2e81f44-6f94-4699-81e2-292ae5d4c0a8_model.json b/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/e2e81f44-6f94-4699-81e2-292ae5d4c0a8_model.json new file mode 100644 index 0000000000000000000000000000000000000000..65833e4b264cde87f3f09eb31903be09cb6fb4cc --- /dev/null +++ b/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/e2e81f44-6f94-4699-81e2-292ae5d4c0a8_model.json @@ -0,0 +1,2288 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.807, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.096, + 0.131, + 0.877, + 0.154 + ], + "angle": 0, + "content": "Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning" + }, + { + "type": "text", + "bbox": [ + 0.279, + 0.181, + 0.718, + 0.218 + ], + "angle": 0, + "content": "Fan Lyu, Qing Sun, Fanhua Shang, Liang Wan, Wei Feng* \nCollege of Intelligence and Computing, Tianjin University" + }, + { + "type": "text", + "bbox": [ + 0.217, + 0.22, + 0.756, + 0.235 + ], + "angle": 0, + "content": "{fanlyu, sssunqing, fhshang, lwan}@tju.edu.cn, wfeng@ieee.org" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.269, + 0.314, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.302, + 0.474, + 0.62 + ], + "angle": 0, + "content": "In Parallel Continual Learning (PCL), the parallel multiple tasks start and end training unpredictably, thus suffering from both training conflict and catastrophic forgetting issues. The two issues are raised because the gradients from parallel tasks differ in directions and magnitudes. Thus, in this paper, we formulate the PCL into a minimum distance optimization problem among gradients and propose an explicit Asymmetric Gradient Distance (AGD) to evaluate the gradient discrepancy in PCL. AGD considers both gradient magnitude ratios and directions, and has a tolerance when updating with a small gradient of inverse direction, which reduces the imbalanced influence of gradients on parallel task training. Moreover, we present a novel Maximum Discrepancy Optimization (MaxDO) strategy to minimize the maximum discrepancy among multiple gradients. Solving by MaxDO with AGD, parallel training reduces the influence of the training conflict and suppresses the catastrophic forgetting of finished tasks. Extensive experiments validate the effectiveness of our approach on three image recognition datasets in task-incremental and class-incremental PCL. Our code is available at https://github.com/fanlyu/maxdo." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.666, + 0.21, + 0.683 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.692, + 0.471, + 0.875 + ], + "angle": 0, + "content": "Continual Learning (CL) [25, 27, 31, 43], aims to continuously learn new knowledge from a sequence of tasks with non-overlapping data streams over a lifelong time. In the era of Internet of Things, people are using many smart devices, where multi-source data and tasks would be accessed at any time. A CL system should respond to parallel data streams from multiple devices. We study Parallel Continual Learning (PCL), as shown in Fig. 1, where an unfixed number of tasks are trained in a parallel way at any time. Specifically, according to the access time of each task, PCL builds an adaptive number of parallel data pipes, thus enabling instant response to new-coming tasks without pending." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.27, + 0.895, + 0.543 + ], + "angle": 0, + "content": "Due to the parallel data streams from different tasks, PCL suffers from not only the catastrophic forgetting but the training conflict among parallel tasks. Most existing methods in CL are proposed to tackle the catastrophic forgetting [19, 25], including regularization-based [25, 8, 16, 51, 1], rehearsal-based [31, 9, 21, 4, 41, 36], and architecture-based [33, 49, 39, 38] methods. In PCL, the training processes of different tasks are diverse, i.e., each task starts and ends training unpredictably (see Fig. 1). Thereby the gradient from different task differs in direction and magnitude [50] and may be neutralized. The gradient discrepancies lead to catastrophic forgetting and training conflict issues, which may fail the learning of some tasks. At any time in PCL, therefore, we present that the problem can be formulated to find an optimal gradient in a minimum distance multi-objective optimization, where each objective is to minimize the distance to a target gradient. In general, the distance metric is proportional to the effect of the optimal gradient on the corresponding task." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.548, + 0.895, + 0.791 + ], + "angle": 0, + "content": "In most situations, the mentioned distance metric \\( D \\) between gradients is set to symmetric intuitively, such as the Euclidean distance and cosine distance. In other words, we usually have \\( D(\\mathbf{x},\\mathbf{y}) = D(\\mathbf{y},\\mathbf{x}) \\) for any \\( \\mathbf{x} \\) and \\( \\mathbf{y} \\). However, the gradient influence is imbalanced among parallel tasks in the gradient descent. For example, in Fig. 1, at the marked time, we have three gradients with diverse directions and magnitudes, and updating with any of them provides different influences to the other two. In the minimum distance problem, the optimal solution should have the minimum negative influence on all parallel tasks, but using symmetric metrics means the influences are optimized indistinguishably at the same time. Due to the fact that the gradients are with wide differences, the solution may have large biases, which would get the near-fitting task out of its local minimum but has less impact on a new-coming task." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.894, + 0.903 + ], + "angle": 0, + "content": "To measure the gradient discrepancy, we hold the opinion that the distance metric in the min-distance problem should be asymmetric. First, though the metric is bound up with both the gradient magnitude and direction, the influences on model training from gradients should be asymmetric, where the model should have more tolerance to small gradients even if they indicate an inverse direction. Second, because" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.222, + 0.9 + ], + "angle": 0, + "content": "*Corresponding author." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "11411" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.09, + 0.443, + 0.221 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.159, + 0.224, + 0.353, + 0.238 + ], + "angle": 0, + "content": "Parallel Continual Learning" + }, + { + "type": "image", + "bbox": [ + 0.453, + 0.09, + 0.603, + 0.221 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.453, + 0.224, + 0.604, + 0.239 + ], + "angle": 0, + "content": "Gradient Discrepancy" + }, + { + "type": "image", + "bbox": [ + 0.613, + 0.091, + 0.89, + 0.221 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.651, + 0.224, + 0.866, + 0.238 + ], + "angle": 0, + "content": "Minimize Asymmetric Distance" + }, + { + "type": "image_caption", + "bbox": [ + 0.075, + 0.243, + 0.894, + 0.285 + ], + "angle": 0, + "content": "Figure 1. Overview of the proposed method in PCL. Left: PCL trains parallel tasks according to their access time without pending. Middle: At any time, gradients from different tasks (corresponding colors) have unpredicted direction and magnitude (the length of vectors). Right: We formulate PCL into a min-distance problem and propose an asymmetric distance for effective optimization." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.31, + 0.47, + 0.43 + ], + "angle": 0, + "content": "gradients are with different magnitudes, the discrepancy between two large gradients is often set to larger than that between small gradients when using symmetric distance, such as Euclidean distance. Directly optimizing using magnitude-aware distance values may lead to the solution close to large gradients and thus hinder the kepping of old tasks. To mitigate the bias from the magnitude difference, it is better to employ the magnitude ratio instead of magnitude itself." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.43, + 0.471, + 0.732 + ], + "angle": 0, + "content": "Motivated by this, in this paper, we propose an explicit measurement for the learning from gradient discrepancy in PCL, named Asymmetric Gradient Distance (AGD), which considers gradient magnitude ratios and directions, and sets a tolerance for smaller gradients. As shown in Fig. 1, the proposed AGD is used in solving the minimum distance problem with multiple gradients from parallel tasks. Then, we propose an effective optimization strategy for minimizing the gradient discrepancy to avoid self-interference. We name the strategy Maximum Discrepancy Optimization (MaxDO), which minimizes the maximum discrepancy from each gradient to the others. Moreover, to address the catastrophic forgetting issue, we follow the rehearsal strategy [31] in traditional CL and build an extra memory data stream. The rehearsal data stream is used to provide a gradient of finished tasks in MaxDO. Solving by MaxDO with AGD, parallel training mitigates the impacts of the diverse training process and slows the catastrophic forgetting of finished tasks. Extensive results on three datasets show the superiority and effectiveness of our approach." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.733, + 0.351, + 0.746 + ], + "angle": 0, + "content": "Our main contributions are three-fold:" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.75, + 0.469, + 0.81 + ], + "angle": 0, + "content": "(1) We formulate the PCL into a minimum distance problem and compare symmetric and asymmetric distances. We show that symmetric metrics are not effective in solving the problem and suggest asymmetric metrics." + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.811, + 0.47, + 0.87 + ], + "angle": 0, + "content": "(2) We propose an asymmetric metric, named AGD, to evaluate the gradient discrepancy, which is proportional to the gradient magnitude ratios and directions. AGD measures the imbalance of gradient influence in PCL." + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.871, + 0.471, + 0.901 + ], + "angle": 0, + "content": "(3) We propose MaxDO for minimizing gradient discrepancy of different tasks, which maximally reduces the" + }, + { + "type": "list", + "bbox": [ + 0.078, + 0.75, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.526, + 0.31, + 0.894, + 0.356 + ], + "angle": 0, + "content": "asymmetric discrepancy from a gradient to the others. MaxDO avoids the self-interference among gradients and reduces training conflict and catastrophic forgetting." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.368, + 0.642, + 0.383 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.393, + 0.69, + 0.409 + ], + "angle": 0, + "content": "2.1. Continual Learning" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.416, + 0.895, + 0.643 + ], + "angle": 0, + "content": "Continual Learning (CL) represents receiving data from new domains continually. In traditional CL, the new domains show up one by one, say serial CL. CL methods can be classified into three kinds. (1) Rehearsal [31, 9, 21, 4, 41, 36, 32], which saves or generates data of old tasks for retraining together with the current training. (2) Regularization [25, 8, 16, 51, 1, 17], which leverages extra regularization terms to consolidate previous knowledge when learning new tasks. (3) Dynamic architecture [33, 49, 39, 38], which freezes task-specific parameters and grows new branches for new tasks automatically. However, most of the existing CL methods are designed for reducing catastrophic forgetting in the serial scenario. Contrastively, in PCL, we need to tackle not only catastrophic forgetting but training conflict among parallel tasks, which is somehow related to multi-task learning." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.651, + 0.697, + 0.667 + ], + "angle": 0, + "content": "2.2. Multi-Task Learning" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.674, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Multi-Task Learning (MTL) [7] is used to address multiple tasks with a single model from one to many domains. Traditional MTL solutions can be mainly grouped into feature-based and parameter-based approaches [52]. The feature-based approaches focus on learning common feature representations for multiple tasks [34, 45]. The parameter-based approaches use model parameters in a task to help learn model parameters in other tasks [44, 5, 23]. Recently, some MTL methods propose to find an optimal gradient for updating and can be categorized into three types. (1) Learning-based methods [11], which learn a set of weights by backpropagation. (2) Solving-based methods [40, 29], solve the problem by finding an optimal gradient that is not dominated by the gradient from any task. (3) Calculating-based methods [30, 24, 12, 46, 50, 20, 28] compute the gradient weights" + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "11412" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.152 + ], + "angle": 0, + "content": "by combining gradients or losses of all tasks. Inspired by MTL, we also formulate the problem into finding an optimal gradient. Specifically, we consider that the optimal gradient should have a small distance to all gradients." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.162, + 0.265, + 0.178 + ], + "angle": 0, + "content": "2.3. Asymmetric Metric" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.186, + 0.473, + 0.384 + ], + "angle": 0, + "content": "In most situations in neural network, the distance is set to symmetric, e.g., the Euclidean distance. However, the symmetric metric is not always suitable for finding the optimal gradient (see the next section for details). Asymmetric metric [14, 35], also known as quasi-metric [14] or pseudo metric [18, 6], is a generalization of a metric but the symmetry axiom is eliminated in the definition of metric spaces. A classical example of asymmetric metric is the taxicab geometry topology including one-way streets, where a path from point A to B has different streets compared to a path from B to A. In this paper, we propose to measure the gradient discrepancy using an asymmetric metric and raise a novel optimization strategy to minimize the maximum discrepancy." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.397, + 0.226, + 0.414 + ], + "angle": 0, + "content": "3. Our Approach" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.421, + 0.332, + 0.438 + ], + "angle": 0, + "content": "3.1. Parallel Continual Learning" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.445, + 0.473, + 0.625 + ], + "angle": 0, + "content": "On a timeline, given a sequence of \\(T\\) tasks with parallel data streams \\(\\{\\mathcal{D}_1,\\dots ,\\mathcal{D}_T\\}\\) for continual training, and each data stream can be accessed and suspended at any time. For simplest, we assume each data stream is i.i.d., and tasks are accessed in order from 1 to \\(T\\) and there exists no real gap that no data stream flows on the timeline. Note that traditional CL is an edge situation of PCL that all tasks are nose-to-tail. A PCL model contains a shared backbone with parameter \\(\\theta\\) to learn task-agnostic knowledge and adaptively incremental number of task-specific classifiers with parameters \\(\\theta_{i}\\). When a new task is accessed, a corresponding task-specific classifier will be constructed." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.627, + 0.471, + 0.779 + ], + "angle": 0, + "content": "In PCL, a task will be forgotten by learning any other tasks when its data stream ends. To avoid forgetting, we leverage the popular rehearsal strategy [31, 9, 21, 4, 41, 36] in our training. Rehearsal builds an extra data stream sampled from all seen tasks and retrans them to suppress the forgetting of finished tasks. For convenience, we denote the rehearsal data stream as \\(\\mathcal{D}_0\\). At time \\(t\\), we use \\(\\mathcal{T}_t\\) to represent the activated data streams (including \\(\\mathcal{D}_0\\)). Together with the rehearsal data stream, PCL training yields the following dynamic multi-objective empirical risk minimization:" + }, + { + "type": "equation", + "bbox": [ + 0.168, + 0.79, + 0.47, + 0.815 + ], + "angle": 0, + "content": "\\[\n\\min _ {\\boldsymbol {\\theta}, \\left\\{\\boldsymbol {\\theta} _ {i} \\mid i \\in \\mathcal {T} _ {t} \\right\\}} \\quad \\left\\{\\ell_ {i} \\left(\\mathcal {D} _ {i}\\right) \\mid i \\in \\mathcal {T} _ {t} \\right\\}. \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.826, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Because the task-specific classifiers are updated by their own gradients \\(\\theta_{i}\\gets \\theta_{i} - \\alpha_{i}\\nabla_{\\theta_{i}}\\ell_{i}\\) \\((\\forall i\\in T_{t})\\) with step size \\(\\alpha_{i}\\), we focus on the update of the shared backbone \\(\\pmb{\\theta}\\). At any PCL step, the goal of dynamic MOO is to optimize multiple objectives simultaneously while updating only once, and" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.182 + ], + "angle": 0, + "content": "the only update of the shared parameters depends on the gradients of all in-training tasks. It will exit an uncertain number of tasks, and each task will provide a task-specific gradient on the shared parameter \\(\\theta\\). Let \\(\\mathbf{g}_i = \\nabla_\\theta \\ell_i\\) and \\(\\alpha\\) be a step size for optimization. The problem of the backbone update can be formulated as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.527, + 0.189, + 0.892, + 0.207 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {\\theta} \\leftarrow \\boldsymbol {\\theta} - \\alpha \\mathbf {d} ^ {*}, \\quad \\text {w h e r e} \\mathbf {d} ^ {*} = f \\left(\\left\\{\\mathbf {g} _ {i} | \\forall i \\in \\mathcal {T} _ {t} \\right\\}\\right). \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.213, + 0.895, + 0.273 + ], + "angle": 0, + "content": "The key question is how to compute the optimal gradient \\(\\mathbf{d}^*\\) via the function \\(f(\\cdot)\\). In this paper, we define the function \\(f(\\cdot)\\) as a min-distance multi-objective problem by minimizing the gradient distance from all in-training tasks:" + }, + { + "type": "equation", + "bbox": [ + 0.568, + 0.28, + 0.892, + 0.302 + ], + "angle": 0, + "content": "\\[\n\\mathbf {d} ^ {*} = \\arg \\min _ {\\mathbf {d}} \\quad \\left\\{D \\left(\\mathbf {d}, \\mathbf {g} _ {i}\\right) \\mid \\forall i \\in \\mathcal {T} \\right\\}, \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.307, + 0.892, + 0.383 + ], + "angle": 0, + "content": "where we need to identify what distance metric \\( D \\) is used to measure gradient discrepancy. The motivation of Eq. (3) is that for the task \\( i \\) in PCL, its own gradient \\( \\mathbf{g}_i \\) is the most qualified update direction for itself. The solution \\( \\mathbf{d}^* \\) should be as close to every gradient as possible." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.383, + 0.895, + 0.459 + ], + "angle": 0, + "content": "A related but different task is Federated Continual Learning (FCL) [48, 42]. Most FCL methods primarily focus on serial training, involving multiple clients in training a shared task at the same time. It is meaningful to study Federated PCL in the future for the advancement of privacy protection." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.466, + 0.891, + 0.483 + ], + "angle": 0, + "content": "3.2. Measuring Asymmetric Gradient Discrepancy" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.489, + 0.895, + 0.659 + ], + "angle": 0, + "content": "To measure gradient discrepancy, the Euclidean Distance (EuDist, \\( D(\\mathbf{x},\\mathbf{y}) = \\| \\mathbf{x} - \\mathbf{y}\\| \\in [0,\\infty) \\)) and Cosine Distance (CosDist, \\( D(\\mathbf{x},\\mathbf{y}) = 1 - \\frac{\\mathbf{x}^\\top\\mathbf{y}}{\\|\\mathbf{x}\\|\\|\\mathbf{y}\\|} \\in [0,2] \\)) are the two most popular choices. Both of them are symmetric, i.e., \\( D(\\mathbf{x},\\mathbf{y}) = D(\\mathbf{y},\\mathbf{x}) \\). A symmetric metric \\( D(\\mathbf{x},\\mathbf{y}) \\) means the forward influence (\\(\\mathbf{x}\\) to \\(\\mathbf{y}\\)) and backward influence (\\(\\mathbf{y}\\) to \\(\\mathbf{x}\\)) are equal. For example, given two in-training tasks A and B, the distance \\( D(\\mathbf{g}_{\\mathrm{A}},\\mathbf{g}_{\\mathrm{B}}) \\) represents both the effect of \\(\\mathbf{g}_{\\mathrm{A}}\\) on task B and \\(\\mathbf{g}_{\\mathrm{B}}\\) on task A because of \\( D(\\mathbf{g}_{\\mathrm{A}},\\mathbf{g}_{\\mathrm{B}}) = D(\\mathbf{g}_{\\mathrm{B}},\\mathbf{g}_{\\mathrm{A}}) \\). Note that large distance from \\(\\mathbf{g}_{\\mathrm{A}}\\) to \\(\\mathbf{g}_{\\mathrm{B}}\\) means large negative influence on the training of task B with \\(\\mathbf{g}_{\\mathrm{A}}\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.66, + 0.895, + 0.87 + ], + "angle": 0, + "content": "However, the model update is highly related to gradient magnitude and direction, which are asymmetric to model updating. The influence of the gradient \\(\\mathbf{g}_{\\mathrm{A}}\\) on task B may be quite different from that of the gradient \\(\\mathbf{g}_{\\mathrm{B}}\\) on task A. In previous studies [31, 9, 50], the two tasks are treated as conflict when \\(\\langle \\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}} \\rangle < 0\\). In PCL, due to the diverse training process, gradients from parallel tasks are diverse in magnitude and direction. When \\(\\| \\mathbf{g}_{\\mathrm{A}} \\| \\ll \\| \\mathbf{g}_{\\mathrm{B}} \\|\\), the gradient \\(\\mathbf{g}_{\\mathrm{A}}\\) will have little negative influence on task B even if \\(\\langle \\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}} \\rangle < 0\\); when \\(\\| \\mathbf{g}_{\\mathrm{A}} \\| \\gg \\| \\mathbf{g}_{\\mathrm{B}} \\|\\) (e.g., a new task A is accessed when task B has been trained for some time near convergence), the update produces huge impact on task B even if \\(\\langle \\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}} \\rangle > 0\\). Using traditional symmetric distances can hardly represent the asymmetric update influence difference." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "To effectively measure gradient discrepancy in PCL, we introduce the asymmetric metric." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "11413" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.09, + 0.089, + 0.341, + 0.252 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.168, + 0.26, + 0.269, + 0.278 + ], + "angle": 0, + "content": "(a) \\(z = 1 - \\frac{\\mathbf{x}^{\\mathrm{T}}\\mathbf{y}}{||\\mathbf{x}||||\\mathbf{y}||}\\)" + }, + { + "type": "image", + "bbox": [ + 0.358, + 0.089, + 0.61, + 0.253 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.411, + 0.26, + 0.562, + 0.274 + ], + "angle": 0, + "content": "(b) \\(z = \\| \\mathbf{x} - \\mathbf{y}\\|\\) , \\(\\| \\mathbf{y}\\| = 0.2\\)" + }, + { + "type": "image", + "bbox": [ + 0.626, + 0.09, + 0.872, + 0.253 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.704, + 0.259, + 0.806, + 0.278 + ], + "angle": 0, + "content": "(c) \\(z = \\frac{\\|\\mathbf{x} - \\mathbf{y}\\|}{\\|\\mathbf{y}\\| + \\|\\mathbf{x} - \\mathbf{y}\\|}\\)" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.279, + 0.894, + 0.32 + ], + "angle": 0, + "content": "Figure 2. The measures of two gradient discrepancy from \\(\\mathbf{x}\\) to \\(\\mathbf{y}\\). Note that the \\(x\\)- and \\(y\\)-axes are the angle (i.e., \\(\\angle \\mathbf{x}, \\mathbf{y}\\)) between \\(\\mathbf{x}\\) and \\(\\mathbf{y}\\), and the magnitude ratio \\(\\frac{\\|\\mathbf{x}\\|}{\\|\\mathbf{y}\\|}\\), respectively. (a) Cosine distance; (b) Euclidean distance where \\(\\|\\mathbf{y}\\| = 0.2\\) as an example; (c) Asymmetric gradient distance. Please see Appendix for the contours." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.345, + 0.47, + 0.375 + ], + "angle": 0, + "content": "Lemma 1 (Asymmetric Metric [14]) \\(D:\\mathcal{X}\\times \\mathcal{X}\\to \\mathbb{R}\\) is an asymmetric metric (a.k.a. quasi-metric [47]) if \\(D\\) satisfies" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.378, + 0.381, + 0.394 + ], + "angle": 0, + "content": "(1) \\(D(\\mathbf{x},\\mathbf{y})\\geq 0\\) and \\(\\forall \\mathbf{x}\\in \\mathbb{R}^d,D(\\mathbf{x},\\mathbf{x}) = 0;\\)" + }, + { + "type": "text", + "bbox": [ + 0.079, + 0.394, + 0.411, + 0.41 + ], + "angle": 0, + "content": "(2) \\(D(\\mathbf{x},\\mathbf{z})\\leq D(\\mathbf{x},\\mathbf{y}) + D(\\mathbf{y},\\mathbf{z}),\\forall \\mathbf{x},\\mathbf{y},\\mathbf{z}\\in \\mathbb{R}^{d}.\\)" + }, + { + "type": "list", + "bbox": [ + 0.078, + 0.378, + 0.411, + 0.41 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.417, + 0.471, + 0.478 + ], + "angle": 0, + "content": "The asymmetric metric does not require the symmetric property, i.e., \\( D(\\mathbf{x}, \\mathbf{y}) = D(\\mathbf{y}, \\mathbf{x}) \\). Based on the definition, in this paper, we design an asymmetric metric to measure gradient discrepancy named Asymmetric Gradient Distance." + }, + { + "type": "title", + "bbox": [ + 0.076, + 0.491, + 0.445, + 0.505 + ], + "angle": 0, + "content": "Definition 1 (Asymmetric Gradient Distance (AGD))" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.506, + 0.47, + 0.536 + ], + "angle": 0, + "content": "Given two gradient \\(\\mathbf{g}_A\\) and \\(\\mathbf{g}_B\\), the asymmetric gradient distance is defined as" + }, + { + "type": "equation", + "bbox": [ + 0.091, + 0.547, + 0.455, + 0.6 + ], + "angle": 0, + "content": "\\[\n\\widehat {D} (\\mathbf {g} _ {A}, \\mathbf {g} _ {B}) = \\left\\{ \\begin{array}{c l} 0 & , \\quad i f \\mathbf {g} _ {A} = \\mathbf {g} _ {B} = \\mathbf {0}, \\\\ \\frac {\\| \\mathbf {g} _ {A} - \\mathbf {g} _ {B} \\|}{\\| \\mathbf {g} _ {B} \\| + \\| \\mathbf {g} _ {A} - \\mathbf {g} _ {B} \\|}, & O t h e r w i s e. \\end{array} \\right.\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.616, + 0.47, + 0.722 + ], + "angle": 0, + "content": "In Definition 1, we consider the edge situation when \\(\\mathbf{g}_{\\mathrm{A}} = \\mathbf{g}_{\\mathrm{B}} = \\mathbf{0}\\) to meet the definition of the asymmetric metric in Lemma 1. In AGD, gradient directions and magnitudes are considered. Instead of using gradient magnitude value difference, we use magnitude ratio difference to avoid the diverse training of different tasks in PCL. Therefore, we derive the corollary of the magnitude ratio:" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.731, + 0.468, + 0.748 + ], + "angle": 0, + "content": "Corollary 1 \\(\\widehat{D} (\\mathbf{g}_A,\\mathbf{g}_B)\\) is an asymmetric metric and holds" + }, + { + "type": "equation", + "bbox": [ + 0.105, + 0.759, + 0.443, + 0.796 + ], + "angle": 0, + "content": "\\[\n\\lim_{\\substack{\\| \\mathbf{g}_{A}\\| \\\\ \\| \\mathbf{g}_{B}\\| \\to \\infty}}\\widehat{D} (\\mathbf{g}_{A},\\mathbf{g}_{B}) = 1,\\quad \\lim_{\\substack{\\| \\mathbf{g}_{A}\\| \\\\ \\| \\mathbf{g}_{B}\\| \\to 0}}\\widehat{D} (\\mathbf{g}_{A},\\mathbf{g}_{B}) = \\frac{1}{2}.\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.471, + 0.902 + ], + "angle": 0, + "content": "We illustrate why AGD is qualified to evaluate the gradient discrepancy according to the definition and corollary. In Definition 1, we use AGD to represent the influence of \\(\\mathbf{g}_{\\mathrm{A}}\\) on task B rather than the inverse. This is the key difference from the symmetric metrics such as Euclidean distance. Specifically, \\(\\mathbf{g}_{\\mathrm{A}}\\) may make task B worse if \\(\\widehat{D}(\\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}})\\) is large (close" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.344, + 0.895, + 0.481 + ], + "angle": 0, + "content": "to 1). If \\(\\widehat{D}(\\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}})\\) is close to 0, \\(\\mathbf{g}_{\\mathrm{A}}\\) and \\(\\mathbf{g}_{\\mathrm{B}}\\) has less conflict. Moreover, Corollary 1 involves that when \\(\\|\\mathbf{g}_{\\mathrm{A}}\\| \\ll \\|\\mathbf{g}_{\\mathrm{B}}\\|\\), AGD has a tolerance \\(\\frac{1}{2}\\) even if \\(\\langle \\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}} \\rangle < 0\\), which means the impact of \\(\\mathbf{g}_{\\mathrm{A}}\\) on task B is mild. This is because updating with a zero gradient will neither improve nor damage the performance. Even though, we prefer positive influence rather than non-influence. Thus, we define that the distance \\(\\widehat{D}(\\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}})\\) in this situation is the mid-level \\((\\frac{1}{2})\\) in the value range([0,1]). See different tolerances in our experiments." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.481, + 0.895, + 0.618 + ], + "angle": 0, + "content": "Moreover, we compare AGD (Fig. 2(c)) with Euclidean and cosine distance in Fig. 2. First, the cosine distance (Fig. 2(a)) is magnitude irrelevant, which ignores the magnitude difference in PCL. Second, the Euclidean distance (Fig. 2(b)) depends heavily on the magnitude value difference, but ignores that the gradient influence on the model update is asymmetric. For example, when \\(\\| \\mathbf{x}\\| \\to 0\\), EuDist will get large if we have large \\(\\| \\mathbf{y}\\|\\) without any tolerance, which ignores the non-influence of zero gradient." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.626, + 0.822, + 0.643 + ], + "angle": 0, + "content": "3.3. Maximum Discrepancy Optimization" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.65, + 0.894, + 0.772 + ], + "angle": 0, + "content": "At time \\(t\\), let the optimal solution to Problem (3) be \\(\\mathbf{d}^*\\), where \\(\\mathcal{T}_t\\) is the index set of in-training tasks (\\(\\mathcal{T}\\) for simplicity). However, directly optimizing the problem is difficult due to the large decision space that has the same dimension as \\(\\pmb{\\theta}\\). Following [28, 40], we use linear scalarization to solve the transformed problem that allows only optimizing decision variable \\(\\mathbf{w} \\in \\mathbb{R}^{|\\mathcal{T}|}\\). That is, let \\(\\mathbf{d} = \\sum_{i \\in \\mathcal{T}} \\mathbf{w}_i \\mathbf{g}_i\\), where \\(\\forall \\mathbf{w}_i \\geq 0\\) and \\(\\sum_{i \\in \\mathcal{T}} \\mathbf{w}_i = 1\\), we have" + }, + { + "type": "equation", + "bbox": [ + 0.515, + 0.782, + 0.892, + 0.832 + ], + "angle": 0, + "content": "\\[\n\\mathbf {w} ^ {*} = \\underset {\\mathbf {w}} {\\arg \\min } \\quad \\left\\{\\widehat {D} \\left(\\sum_ {j} \\mathbf {w} _ {j} \\mathbf {g} _ {j}, \\mathbf {g} _ {i}\\right) | \\forall i \\in \\mathcal {T} \\right\\}. \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.894, + 0.902 + ], + "angle": 0, + "content": "Each objective of the dual problem will be highly affected by the minimum discrepancy, i.e., each gradient itself. For example, by minimizing objective \\(\\widehat{D} (\\sum_{j}\\mathbf{w}_{j}\\mathbf{g}_{j},\\mathbf{g}_{i})\\) , weight \\(\\mathbf{w}_i\\) is more like to be activated than others. Thus, multiple" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "11414" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.08, + 0.088, + 0.895, + 0.284 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.288, + 0.895, + 0.348 + ], + "angle": 0, + "content": "Figure 3. Schematic of Maximum Discrepancy Optimization. Given multiple gradients \\(\\{\\mathbf{g}_i|\\forall i\\in \\mathcal{T}\\}\\) \\((|\\mathcal{T}| = 4\\) for example) (1) A weight matrix \\(\\mathbf{W}\\) is initialized with \\(\\frac{1}{|\\mathcal{T}|}\\) for each entry. (2) For each row, the off-diagonal entries are used to weighted gradients and optimized for minimum AGD to the target gradient. (3) The diagonal entries \\((\\square)\\) are used to optimize with min-norm with MGDA. (4) The final weight matrix is reduced by each column for the final weights \\((w^{\\prime})\\). See Sec. 3.3 for details." + }, + { + "type": "code_caption", + "bbox": [ + 0.088, + 0.373, + 0.319, + 0.388 + ], + "angle": 0, + "content": "Algorithm 1: MaxDO ( ) in PCL" + }, + { + "type": "algorithm", + "bbox": [ + 0.082, + 0.39, + 0.437, + 0.594 + ], + "angle": 0, + "content": "Input: Parameters \\(\\theta ,\\theta_{1:T}\\) ; Step sizes \\(\\alpha\\) \\(\\alpha_{1:T}\\) Output: \\(\\theta ,\\theta_{1:T}\\) \n1 for t in timeline do \n2 \\(\\mathcal{T}_t\\gets\\) in-training task index; \n3 for \\(i\\in \\mathcal{T}_t\\) do \n4 \\(\\begin{array}{r}\\mathcal{B}_i\\sim \\mathcal{D}_i;\\\\ \\pmb {\\theta}_i\\gets \\pmb {\\theta}_i - \\alpha_i\\nabla_{\\pmb{\\theta}_i}\\ell_i(\\mathcal{B}_i);\\\\ \\mathbf{g}_i = \\nabla_\\theta \\ell_i(\\mathcal{B}_i); \\end{array}\\) \n5 \n6 end \n7 W\\* Optimization by Eq. (5); d\\* Final graident from Eq. (6); \n8 \n9 \\(\\theta \\leftarrow \\theta -\\alpha \\mathbf{d}^{*};\\)" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.632, + 0.47, + 0.678 + ], + "angle": 0, + "content": "objectives will be compromised by multiple self-interference but fail to reduce the maximum discrepancy in the dual problem optimization." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.68, + 0.473, + 0.902 + ], + "angle": 0, + "content": "As shown in Fig. 3, we propose Maximum Discrepancy Optimization (MaxDO) to reduce the maximum gradient discrepancy. Specifically, instead of the weight vector \\(\\mathbf{w} \\in \\mathbb{R}^{|\\mathcal{T}|}\\), we optimize a weight matrix \\(\\mathbf{W} \\in \\mathbb{R}^{|\\mathcal{T}| \\times |\\mathcal{T}|}\\) in which \\(\\forall \\mathbf{W}_{ij} \\geq 0\\). \\(\\mathbf{W}\\) can be combined by a diagonal vector \\(\\dot{\\mathbf{w}} = [\\mathbf{W}_{1,1}, \\dots, \\mathbf{W}_{|\\mathcal{T}|,|\\mathcal{T}|}]\\) and an off-diagonal matrix \\(\\widetilde{\\mathbf{W}} = \\mathbf{W} - \\mathrm{Diag}(\\dot{\\mathbf{w}})\\), where \\(\\sum_{i \\in \\mathcal{T}} \\dot{\\mathbf{w}}_i = 1\\) and \\(\\sum_{j \\in \\mathcal{T}} \\widetilde{\\mathbf{W}}_{ij} = 1, \\forall i\\). Thus, \\(\\sum_{i,j \\in \\mathcal{T}} \\mathbf{W}_{ij} = |\\mathcal{T}| + 1\\) and the two weights are independent and can be optimized without disturbance as follows: (1) \\(\\widetilde{\\mathbf{W}}\\), computed by Stochastic Gradient Descent (SGD), is used to make up the maximum gradient discrepancy. The objectives of any two rows in \\(\\widetilde{\\mathbf{W}}\\) are different. For row \\(i\\), to formulate the maximum discrepancy of gradient \\(\\mathbf{g}_i\\), the objective is the combina" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.369, + 0.896, + 0.598 + ], + "angle": 0, + "content": "tion of non-diagonal entries. The weighted other gradients should be with the smallest asymmetric distance to \\(\\mathbf{g}_i\\). (2) \\(\\dot{\\mathbf{w}}\\) is obtained by the Multiple Gradient Descent Algorithm (MGDA) [15], which is to obtain a weighted gradient that does not damage any tasks with a min-norm optimization. The objective of MGDA is 0 and the resulting point satisfies the Karush-Kuhn-Tucker condition or the solution gives a Pareto descent direction that improves all tasks. See Appendix for more details of MGDA. For each off-diagonal entry of the \\(i\\)-th column, their sum means the effect of the gradient \\(\\mathbf{g}_i\\) reducing the maximum discrepancy from other gradients. MGDA is used to reduce the possible negative effect in MaxDO. On the other hand, MaxDO reduces the training failure of new tasks in MGDA. To sum up, our MaxDO with AGD can be computed by" + }, + { + "type": "equation", + "bbox": [ + 0.552, + 0.603, + 0.894, + 0.742 + ], + "angle": 0, + "content": "\\[\n\\mathbf {W} ^ {*} = \\underbrace {\\arg \\min _ {\\widetilde {\\mathbf {W}}} \\sum_ {\\forall i \\in \\mathcal {T}} \\widehat {D} \\left(\\sum_ {j \\neq i} \\widetilde {\\mathbf {W}} _ {i , j} \\mathbf {g} _ {j} , \\mathbf {g} _ {i}\\right)} _ {\\text {S G D w i t h M a x i m u m D i s c r e p a n c y}} + \\operatorname {D i a g} \\underbrace {\\left(\\underset {\\dot {\\mathbf {w}}} {\\arg \\min } \\left\\| \\sum_ {j} \\dot {\\mathbf {w}} _ {j} \\mathbf {g} _ {j} \\right\\|\\right)} _ {\\text {M G D A [ 1 5 ]}}. \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.748, + 0.897, + 0.903 + ], + "angle": 0, + "content": "In Eq. (5), we can obtain an approximate solution by combining the closed-form solution and the iterative solution. Fig. 3 reveals the diagram of solving MaxDO. We project the solution of SGD onto the feasible set \\((\\sum_{i \\neq j} \\mathbf{W}_{ij} = 1)\\) via softmax at each step in the multiple steps for fast convergence. First, we initialize all entries of \\(\\mathbf{W}\\) by \\(\\frac{1}{|\\mathcal{T}|}\\). Then, the off-diagonal matrix is used to minimize the maximum gradient discrepancy via SGD and the diagonal vector is optimized by min-norm. Finally, the final weights are reduced to a vector by dividing \\(|\\mathcal{T}| + 1\\) to guarantee that their sum" + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "11415" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.091, + 0.472, + 0.155 + ], + "angle": 0, + "content": "is 1. Note that, MaxDO is implemented only when \\(|\\mathcal{T}| > 1\\), i.e., multiple tasks are given at the current time. Otherwise, we have \\(\\mathbf{d}^{*} = \\mathbf{g}_{1}\\) for the only current task 1. Thus, the final gradient \\(\\mathbf{d}^{*}\\) is computed by" + }, + { + "type": "equation", + "bbox": [ + 0.097, + 0.164, + 0.47, + 0.233 + ], + "angle": 0, + "content": "\\[\n\\mathbf {d} ^ {*} = \\left\\{ \\begin{array}{l l} \\mathbf {g} _ {1}, & | \\mathcal {T} | = 1, \\\\ \\sum_ {i} \\left(\\frac {1}{| \\mathcal {T} | + 1} \\sum_ {j} \\mathbf {W} _ {j, i} ^ {*}\\right) \\mathbf {g} _ {i}, & | \\mathcal {T} | > 1. \\end{array} \\right. \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.243, + 0.473, + 0.381 + ], + "angle": 0, + "content": "The detailed algorithm is shown in Algorithm 1. With the rehearsal data stream, our algorithm learns a PCL model through a timeline. At the time \\( t \\) on the timeline, given a mini-batch \\( \\mathcal{B} \\) from each data stream, we compute the corresponding gradients on shared and task-specific parameters. The task-specific parameters are updated directly and the gradients on the shared backbone are collected for computed the final updated gradient \\( \\mathbf{d} \\). By using our MaxDO, we update the shared parameters \\( \\theta \\) with the optimal \\( \\mathbf{d}^* \\)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.395, + 0.203, + 0.412 + ], + "angle": 0, + "content": "4. Experiment" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.419, + 0.175, + 0.435 + ], + "angle": 0, + "content": "4.1. Dataset" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.443, + 0.473, + 0.624 + ], + "angle": 0, + "content": "In our experiments, 3 traditional image recognition datasets are transformed into parallel data streams: (1) Parallel Split EMNIST (PS-EMNIST). We split EMNIST [13] (62 classes) into 5 tasks and the size of the label set for each task, i.e., the number of classes, is set to \\{12, 12, 12, 13, 13\\}. (2) Parallel Split CIFAR-100 (PS-CIFAR-100). We split CIFAR-100 into 10 tasks and the size of the label set for each task is set to 10. (3) Parallel Split ImageNet-TINY (PS-ImageNet-TINY). We split Tiny ImageNet [26] (200 classes) into 10 tasks, and the size of the label set for each task is set to 20. We evaluate PCL on task-incremental and class-incremental scenarios. Please see Appendix for more dataset details." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.625, + 0.472, + 0.748 + ], + "angle": 0, + "content": "All three datasets have 3 different label sets (3 different class splits), each of which has 3 different timelines (when to access). For each timeline, we have 3 different runs with fixed seeds 1234, 1235, and 1236 for parameter initialization. In other words, we have 27 different settings for each dataset, and we report the average and standard deviation (avg \\(\\pm\\) std) for each compared method in our experiments. Note that, we omit all blank time that no data stream flows for simplicity." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.757, + 0.265, + 0.773 + ], + "angle": 0, + "content": "4.2. Experiment Details" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.473, + 0.903 + ], + "angle": 0, + "content": "We implement our experiments using Tensorflow and conduct on a single NVidia RTX 3090Ti GPU card. We take a 2-layer MLP as the backbone network for PS-EMNIST and a Resnet-18 [22] for PS-CIFAR-100 and PS-ImageNet-Tiny. The learning rate is set to 0.003, 0.0004 and 0.0005 for PS-EMNIST, PS-CIFAR-100 and PS-ImageNet-Tiny. The SGD in MaxDO has a learning rate of 5. Each task is trained in a data stream, i.e., each data point passes only once. For each" + }, + { + "type": "image", + "bbox": [ + 0.501, + 0.094, + 0.697, + 0.236 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.697, + 0.094, + 0.887, + 0.236 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.533, + 0.239, + 0.855, + 0.254 + ], + "angle": 0, + "content": "Figure 4. Different memory sizes on PS-CIFAR-100." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.279, + 0.892, + 0.323 + ], + "angle": 0, + "content": "task, we set the batch size to 128 per step. For any new task in PCL, we build a new classifier, which is a fully-connected layer with a softmax function." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.324, + 0.894, + 0.386 + ], + "angle": 0, + "content": "To evaluate PCL, we compute the average accuracy and forgetting, following previous continual learning studies [31, 9, 3, 2, 37]. Let \\( e_t \\) be the end time of task \\( t \\) and the final time \\( \\bar{e} = \\max(e_1, e_2, \\dots, e_T) \\), the two metrics are computed as:" + }, + { + "type": "equation", + "bbox": [ + 0.558, + 0.395, + 0.892, + 0.438 + ], + "angle": 0, + "content": "\\[\nA _ {\\bar {e}} = \\frac {1}{T} \\sum_ {t = 1} ^ {T} a _ {\\bar {e}} ^ {t}, \\quad F _ {\\bar {e}} = \\frac {1}{T} \\sum_ {t = 1} ^ {T} a _ {\\bar {e}} ^ {t} - a _ {e _ {t}} ^ {t}, \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.445, + 0.895, + 0.507 + ], + "angle": 0, + "content": "where \\( a_{k}^{j} \\) is the mean testing accuracy of task \\( j \\) at time \\( k \\). \\( A_{\\bar{e}} \\) denotes the final average accuracy on all the tasks, and \\( F_{\\bar{e}} \\) (also known as backward transfer) means the final performance drop compared to each task that was first trained." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.515, + 0.64, + 0.53 + ], + "angle": 0, + "content": "4.3. Main Results" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.539, + 0.895, + 0.704 + ], + "angle": 0, + "content": "We compare our method with MTL methods including MGDA [15], GradNorm [11], DWA [30], GradDrop [12], PCGrad [50] and RLW [28] in the PCL setting. We treat any time on the timeline as an MTL subunit to train PCL. All results of previous MTL methods are produced by ourselves with the claimed design in their papers. We also compare with some rehearsal-based SCL methods including AGEM[9], GMED[37] and ER[10]. To adapt to the SCL methods, we merge batches from every in-training task to mimic a naive sequence learning that only a batch from the current task and a batch from the memory buffer." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.896, + 0.901 + ], + "angle": 0, + "content": "We show the main comparisons with the proposed methods in Tables 1 and 2 on the three datasets. We have several major observations. First, the rehearsal strategy is useful for reducing catastrophic forgetting in PCL for all compared methods. As an extra data stream apart from in-training data streams, rehearsal provides data from the finished tasks training together with other tasks to suppress forgetting. With the rehearsal strategy, the memory may provide continual learning of finished tasks, and even better performance can be obtained, which results in positive forgetting values on \\( F_{\\bar{e}} \\). Second, without task-id, class-incremental PCL has worse performance than task-incremental PCL. Surprisingly, we find that MGDA has good performance than other methods in" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "11416" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.286, + 0.088, + 0.679, + 0.101 + ], + "angle": 0, + "content": "Table 1. Task-incremental comparisons (avg ± std) on 3 datasets." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.102, + 0.894, + 0.285 + ], + "angle": 0, + "content": "
Method (+ Reherasal)TypePS-EMNISTPS-CIFAR-100PS-ImageNet-TINY
A̅̅ (‰)F̅̅ (‰)A̅̅ (‰)F̅̅ (‰)A̅̅ (‰)F̅̅ (‰)
AvgGradMTL89.344 ± 0.231-5.287 ± 0.21647.579 ± 0.08923.691 ± 0.43238.392 ± 0.0760.764 ± 0.139
MGDA [15]MTL84.887 ± 0.469-4.301 ± 0.81848.957 ± 0.45125.088 ± 0.20338.058 ± 0.7401.465 ± 0.490
GradNorm [11]MTL87.888 ± 0.158-6.197 ± 0.18347.210 ± 1.32323.474 ± 0.68838.226 ± 0.7691.647 ± 0.667
DWA [30]MTL88.405 ± 0.322-5.452 ± 0.33844.969 ± 0.37822.682 ± 0.53734.290 ± 1.099-1.053 ± 0.866
PCGrad [50]MTL89.698 ± 0.164-4.921 ± 0.12147.026 ± 0.53823.244 ± 0.74039.427 ± 1.2752.017 ± 0.769
RLW [28]MTL89.288 ± 0.218-5.226 ± 0.20447.574 ± 0.34923.833 ± 0.11738.531 ± 1.6101.332 ± 1.148
AGEM [9]SCL87.022 ± 0.519-7.646 ± 0.48327.379 ± 0.5855.416 ± 0.85128.530 ± 0.994-7.070 ± 1.410
GMED [37]SCL85.471 ± 0.324-8.875 ± 0.33549.094 ± 1.79218.356 ± 1.34534.495 ± 1.568-0.640 ± 1.799
ER [10]SCL89.106 ± 0.315-5.525 ± 0.20747.324 ± 0.58423.330 ± 0.76235.950 ± 0.763-0.767 ± 0.591
MaxDO (AGD)PCL90.189 ± 0.314-4.258 ± 0.31150.203 ± 0.97824.510 ± 0.09240.770 ± 0.3543.119 ± 0.450
" + }, + { + "type": "table_caption", + "bbox": [ + 0.283, + 0.298, + 0.68, + 0.311 + ], + "angle": 0, + "content": "Table 2. Class-incremental comparisons (avg \\( \\pm \\) std) on 3 datasets." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.311, + 0.892, + 0.491 + ], + "angle": 0, + "content": "
Method (+ Reherasal)TypePS-EMNISTPS-CIFAR-100PS-ImageNet-TINY
A̅e(%)F̅e(%)A̅e(%)F̅e(%)A̅e(%)F̅e(%)
AvgGradMTL43.823 ± 0.566-44.484 ± 0.5968.921 ± 0.276-4.985 ± 0.7027.511 ± 0.661-15.825 ± 0.228
MGDA [15]MTL52.823 ± 0.201-7.753 ± 0.53811.323 ± 0.282-4.065 ± 0.7258.318 ± 0.155-13.118 ± 0.739
GradNorm [11]MTL43.292 ± 0.590-44.824 ± 0.6889.477 ± 0.222-4.403 ± 1.2366.395 ± 0.130-15.869 ± 0.336
DWA [30]MTL42.734 ± 0.211-38.944 ± 0.5813.519 ± 0.116-7.470 ± 0.2443.003 ± 0.139-12.774 ± 0.158
PCGrad [50]MTL45.035 ± 0.273-43.309 ± 0.17610.140 ± 0.253-5.149 ± 0.5537.789 ± 0.237-15.860 ± 0.318
RLW [28]MTL44.595 ± 0.480-43.424 ± 0.3259.957 ± 0.135-5.173 ± 0.6137.419 ± 0.258-16.079 ± 0.255
AGEM [9]SCL26.249 ± 0.511-62.480 ± 0.5273.374 ± 0.098-10.462 ± 0.5433.379 ± 0.149-18.514 ± 0.516
GMED [37]SCL22.694 ± 0.153-65.805 ± 0.2554.941 ± 0.407-12.837 ± 0.7103.386 ± 0.348-19.060 ± 0.682
ER [10]SCL43.474 ± 0.860-44.597 ± 0.8619.317 ± 0.339-5.337 ± 0.6266.126 ± 0.277-13.686 ± 0.290
MaxDO (AGD)PCL53.139 ± 0.156-11.903 ± 0.47612.237 ± 0.176-2.280 ± 0.2709.532 ± 0.363-12.511 ± 0.610
" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.518, + 0.474, + 0.82 + ], + "angle": 0, + "content": "class-incremental PCL compared with the task-incremental scenario, which means the suppressing on catastrophic forgetting is more important in class-incremental PCL. Third, the compared MTL methods are designed for balanced training and ignore the diverse training process in PCL, thus some gradients may be counteracted because of the large gradient discrepancy when updating the model. In contrast, our MaxDO with AGD obtains the best final accuracy \\( A^T \\) on three datasets and two scenarios, which shows our superiority in balancing plasticity and stability. For example, we have \\( 40.770\\% \\) and \\( 9.431\\% \\) for PS-ImageNet-TINY on two scenarios respectively, while the compared best value is only \\( 39.427\\% \\) and \\( 8.318\\% \\). On one hand, the proposed AGD is used to measure the asymmetric distance between gradients to boost the effective update of each task. On the other hand, the maximum discrepancies between multiple tasks are reduced. Note that, the forgetting measure of the proposed methods may not outperform the compared methods because we got both better new tasks and final accuracy performance, their difference value may be small." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.832, + 0.32, + 0.848 + ], + "angle": 0, + "content": "4.4. Rehearsal Analysis in PCL" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.471, + 0.903 + ], + "angle": 0, + "content": "In Fig. 4, we compare the effects of different memory buffer sizes (per class) in rehearsal on PS-CIFAR-100. We observe that the memory buffer size affects the remembering" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.518, + 0.895, + 0.701 + ], + "angle": 0, + "content": "of old knowledge, and a larger size means better knowledge keeping, which is similar to traditional CL. Under the same memory size, our method has better performance. Then, in Table 3(a), to show the MaxDO's effectiveness of forgetting reduction on rehearsal gradient, we evaluate the result that only leverages MaxDO on new tasks. In this case, the final gradient is calculated by \\( \\mathbf{d} = \\frac{1}{2}\\mathbf{g}_{\\mathrm{reh}} + \\frac{1}{2}\\mathbf{g}_{\\mathrm{new}} \\), where \\( \\mathbf{g}_{\\mathrm{new}} \\) is the solution gradient via MaxDO on only new parallel tasks, and \\( \\mathbf{g}_{\\mathrm{reh}} \\) means the gradient from the rehearsal data streams. The result shows that it is necessary to put the rehearsal gradient to the MaxDO. Otherwise, the model will get worse accuracy and forgetting." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.709, + 0.822, + 0.725 + ], + "angle": 0, + "content": "4.5. Comparison with Symmetric Metrics" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.732, + 0.895, + 0.901 + ], + "angle": 0, + "content": "As shown in Table 3(b), we compare AGD with three common symmetric metrics including EuDist, CosDist, and Normalized EuDist. EuDist, CosDist are defined in Sec. 3.2. The vanilla EuDist depends highly on the gradient magnitude difference, thus we also compare with its normalized version \\( D(\\mathbf{x},\\mathbf{y}) = \\frac{\\|\\mathbf{x} - \\mathbf{y}\\|}{\\|\\mathbf{x}\\| + \\|\\mathbf{y}\\|} \\in [0,1] \\), namely normalized EuDist (Norm EuDist). The results show that the three metrics can also obtain good performance with MaxDO. However, EuDist fails to reduce catastrophic forgetting effectively because of the over-emphasizing of gradient magnitude difference. Considering only the gradient direction difference, MaxDO" + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "11417" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.123, + 0.088, + 0.842, + 0.101 + ], + "angle": 0, + "content": "Table 3. Reherasal experiemtns, comparisons with symmetric metrics and ablation studies in MaxDO on PS-CIFAR-100." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.102, + 0.894, + 0.281 + ], + "angle": 0, + "content": "
ExperimentMethodTask-incrementClass-increment
A̅e(%)F̅e(%)A̅e(%)F̅e(%)
(a) Rehearsal analysisMaxDO (w/o Rehearsal)25.241 ± 0.4663.128 ± 0.1752.971 ± 0.048-11.356 ± 0.703
MaxDO (w/o Reheerasal gradient)47.653 ± 1.28023.538 ± 1.4689.431 ± 0.469-5.907 ± 0.658
(b) Symmetric metricsMaxDO (EuDist)49.201 ± 0.41024.112 ± 0.19710.189 ± 0.218-7.172 ± 0.796
MaxDO (CosDist)49.154 ± 0.57025.094 ± 0.22211.771 ± 0.139-3.114 ± 0.681
MaxDO (Norm EuDist)48.517 ± 0.33624.386 ± 0.38811.692 ± 0.373-3.228 ± 0.822
(c) Ablation studiesMGDA [15]48.957 ± 0.45125.088 ± 0.20311.323 ± 0.282-4.065 ± 0.725
MaxDO (w/o Max-Discrepancy)47.899 ± 1.02223.874 ± 0.44710.441 ± 0.324-4.807 ± 0.573
MaxDO (w/o MGDA)49.631 ± 0.43125.816 ± 0.56111.881 ± 0.468-2.993 ± 0.964
(d) Our full methodMaxDO (AGD, w/ Reherasal)50.203 ± 0.27424.510 ± 0.09212.237 ± 0.176-2.280 ± 0.270
" + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.309, + 0.272, + 0.446 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.166, + 0.452, + 0.183, + 0.462 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "image", + "bbox": [ + 0.274, + 0.308, + 0.465, + 0.446 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.359, + 0.451, + 0.377, + 0.462 + ], + "angle": 0, + "content": "(b)" + }, + { + "type": "image_caption", + "bbox": [ + 0.157, + 0.466, + 0.384, + 0.48 + ], + "angle": 0, + "content": "Figure 5. Training time comparisons." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.505, + 0.471, + 0.627 + ], + "angle": 0, + "content": "with CosDist obtains better performance than EuDist. But CosDist ignores the magnitude difference, which is also important in the min-distance problem, resulting in insufficient performance. Compared to EuDist, normalized EuDist obtains even worse performance. In contrast, MaxDO with AGD considers the asymmetric influence on gradient update, and tolerance is set to reduce the influence from small gradients to new-access tasks, which yields the best performance." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.636, + 0.232, + 0.652 + ], + "angle": 0, + "content": "4.6. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.66, + 0.473, + 0.901 + ], + "angle": 0, + "content": "We evaluate the impact of the two main components of MaxDO in Table 3(c). First, we block the maximum discrepancy in MaxDO (MaxDO (w/o Max-Discrepancy)), which means that we solve the min-distance problem with Eq. (4) directly. Because of the self-interference, the solution combines the minimum discrepancy but fails to effectively reduce the discrepancy from other gradients (47.899% and 10.441% for \\( A_{\\bar{e}} \\)). We then block the MGDA that obtains a weighted gradient not damage any tasks. MGDA is quite useful in traditional MTL tasks but is not suitable in PCL (w/o MGDA, 49.693% and 11.881% for \\( A_{\\bar{e}} \\)). Because of the diverse training process of parallel tasks, gradients are with large magnitude differences and MGDA prefers to set large factors to small gradients. We solve the problem by both MGDA and the maximum discrepancy, and the whole MaxDO method with AGD outperforms the two ablated" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.306, + 0.895, + 0.336 + ], + "angle": 0, + "content": "methods (50.203% and 12.231% for \\( A_{\\bar{e}} \\)), where the characters of the two components are combined." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.343, + 0.663, + 0.358 + ], + "angle": 0, + "content": "4.7. Procedure Time" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.367, + 0.895, + 0.503 + ], + "angle": 0, + "content": "In Fig. 5, we show the training time comparison on PS-CIFAR-100. We first compare the training time for 2 to 5 parallel tasks in one iteration (Fig. 5(a)). We find that the generation of task numbers will grow the training time, and MaxDO needs more time than other methods because multiple minimum distance optimizations are performed. Then, we show both the final accuracy and whole training time in Fig. 5(b). In the whole timeline, MaxDO gets slightly longer training time than other methods but better performance." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.51, + 0.746, + 0.526 + ], + "angle": 0, + "content": "4.8. Tolerance Analysis in AGD" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.533, + 0.895, + 0.684 + ], + "angle": 0, + "content": "In our paper, AGD is designed to have a tolerance \\(\\frac{1}{2}\\) in Corollary 1. This is because updating with a zero gradient will neither improve nor damage the performance. Even though, we prefer positive influence rather than noninfluence. Thus, we define that the distance \\(\\widehat{D}(\\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}})\\) in the situation \\(\\|\\mathbf{g}_{\\mathrm{A}}\\| \\ll \\|\\mathbf{g}_{\\mathrm{B}}\\|\\) is the mid-level in the value range. Therefore, we study to change the tolerance and observe the performance change. The tolerance can be controlled by adding a factor \\(\\gamma > 0\\) at the denominator. Omitting the edge situation, we have" + }, + { + "type": "equation", + "bbox": [ + 0.571, + 0.69, + 0.822, + 0.723 + ], + "angle": 0, + "content": "\\[\n\\widehat {D} _ {\\gamma} \\left(\\mathbf {g} _ {\\mathrm {A}}, \\mathbf {g} _ {\\mathrm {B}}\\right) = \\frac {\\| \\mathbf {g} _ {\\mathrm {A}} - \\mathbf {g} _ {\\mathrm {B}} \\|}{\\gamma \\| \\mathbf {g} _ {\\mathrm {B}} \\| + \\| \\mathbf {g} _ {\\mathrm {A}} - \\mathbf {g} _ {\\mathrm {B}} \\Vert}.\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.728, + 0.894, + 0.775 + ], + "angle": 0, + "content": "The experiments on different tolerances are shown in Table 4. The results show either larger or smaller tolerances compared to \\(\\frac{1}{2}\\) will get the performance drop during the PCL training." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.785, + 0.62, + 0.8 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.895, + 0.901 + ], + "angle": 0, + "content": "In this paper, we studied to address the training conflict and catastrophic forgetting issues in Parallel Continual Learning (PCL). We presented that the two issues are rooted in the gradient discrepancies and formulated the problem into a minimum distance optimization among gradients. However, the distance metric is often set to be symmetric, which" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "11418" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.118, + 0.089, + 0.423, + 0.101 + ], + "angle": 0, + "content": "Table 4. Comparisons on different tolerance (Tol.)." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.102, + 0.47, + 0.192 + ], + "angle": 0, + "content": "
γTol.Task-incrementClass-increment
A̅e(%)F̅e(%)A̅e(%)F̅e(%)
0.25/646.118 ± 0.46322.617 ± 0.48411.283 ± 0.696-3.158 ± 1.087
0.52/346.452 ± 0.11322.874 ± 0.68011.284 ± 0.343-3.305 ± 0.629
11/250.203 ± 0.27424.510 ± 0.09212.237 ± 0.176-2.280 ± 0.270
21/349.827 ± 0.42025.520 ± 0.61111.603 ± 0.506-3.503 ± 0.687
31/448.766 ± 0.17124.491 ± 0.40611.389 ± 0.738-3.234 ± 1.060
41/548.859 ± 0.62724.714 ± 0.43711.378 ± 0.484-3.189 ± 0.902
" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.223, + 0.474, + 0.496 + ], + "angle": 0, + "content": "is problematic in gradient descent. To evaluate the gradient discrepancy in PCL, we proposed an explicit Asymmetric Gradient Distance (AGD), which considers both gradient magnitude ratios and directions and has a tolerance when updating with a small gradient of inverse direction. Moreover, we proposed a novel Maximum Discrepancy Optimization (MaxDO) strategy to minimize the maximum discrepancy among multiple gradients and avoid self-interference. Solving by MaxDO with AGD, the parallel training in PCL reduces the influence of the training conflict and slows the catastrophic forgetting. We verified the proposed method on three image recognition datasets. The experimental results significantly showed the advantage of MaxDO and the effectiveness of the proposed AGD. We list the latent limitation of our method: (1) The MaxDO cannot guarantee a theoretical Pareto optimum in the training process like MGDA, which means a better trade-off can be obtained in the future. (2) The MaxDO method needs more time for training." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.515, + 0.238, + 0.532 + ], + "angle": 0, + "content": "Acknowledgement" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.543, + 0.472, + 0.618 + ], + "angle": 0, + "content": "We gratefully acknowledge the invaluable support from the following funding bodies: the National Natural Science Foundation of China (62072334, 62276182), and the National Key Research and Development Program of China (2020YFC1522701)." + }, + { + "type": "title", + "bbox": [ + 0.079, + 0.638, + 0.175, + 0.654 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.085, + 0.665, + 0.47, + 0.708 + ], + "angle": 0, + "content": "[1] Rahaf Aljundi, Francesca Babiloni, Mohamed Elhoseiny, Marcus Rohrbach, and Tinne Tuytelaars. Memory aware synapses: Learning what (not) to forget. In ECCV, 2018. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.711, + 0.472, + 0.765 + ], + "angle": 0, + "content": "[2] Rahaf Aljundi, Eugene Belilovsky, Tinne Tuytelaars, Laurent Charlin, Massimo Caccia, Min Lin, and Lucas Page-Caccia. Online continual learning with maximal interfered retrieval. In NeurIPS, 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.769, + 0.471, + 0.811 + ], + "angle": 0, + "content": "[3] Rahaf Aljundi, Min Lin, Baptiste Goujaud, and Yoshua Bengio. Gradient based sample selection for online continual learning. In NeurlPS, 2019. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.814, + 0.471, + 0.87 + ], + "angle": 0, + "content": "[4] Craig Atkinson, Brendan McCane, Lech Szymanski, and Anthony Robins. Pseudo-rehearsal: Achieving deep reinforcement learning without catastrophic forgetting. arXiv preprint arXiv:1812.02464, 2018. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.873, + 0.471, + 0.901 + ], + "angle": 0, + "content": "[5] Aviad Barzilai and Koby Crammer. Convex multi-task learning by clustering. In AISTATS, 2015. 2" + }, + { + "type": "list", + "bbox": [ + 0.085, + 0.665, + 0.472, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.093, + 0.892, + 0.135 + ], + "angle": 0, + "content": "[6] Francesca Cagliari, Barbara Di Fabio, and Claudia Landi. The natural pseudo-distance as a quotient pseudo-metric, and applications. In Forum Mathematicum. De Gruyter, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.136, + 0.892, + 0.149 + ], + "angle": 0, + "content": "[7] Rich Caruana. Multitask learning. Machine learning, 1997. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.511, + 0.151, + 0.894, + 0.205 + ], + "angle": 0, + "content": "[8] Arslan Chaudhry, Puneet K Dokania, Thalaiyasingam Ajthan, and Philip HS Torr. Riemannian walk for incremental learning: Understanding forgetting and intransigence. In ECCV, 2018. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.511, + 0.207, + 0.892, + 0.248 + ], + "angle": 0, + "content": "[9] Arslan Chaudhry, Marc'Aurelio Ranzato, Marcus Rohrbach, and Mohamed Elhoseiny. Efficient lifelong learning with a-gem. In ICLR, 2019. 1, 2, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.25, + 0.892, + 0.305 + ], + "angle": 0, + "content": "[10] Arslan Chaudhry, Marcus Rohrbach, Mohamed Elhoseiny, Thalaiyasingam Ajanthan, Puneet K Dokania, Philip H S Torr, and Marcurelio Ranzato. On tiny episodic memories in continual learning. arXiv: Learning, 2019. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.306, + 0.892, + 0.36 + ], + "angle": 0, + "content": "[11] Zhao Chen, Vijay Badrinarayanan, Chen-Yu Lee, and Andrew Rabinovich. Gradnorm: Gradient normalization for adaptive loss balancing in deep multitask networks. In ICML, 2018. 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.362, + 0.892, + 0.417 + ], + "angle": 0, + "content": "[12] Zhao Chen, Jiquan Ngiam, Yanping Huang, Thang Luong, Henrik Kretzschmar, Yuning Chai, and Dragomir Anguelov. Just pick a sign: Optimizing deep multitask models with gradient sign dropout. In NeurIPS, 2020. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.419, + 0.892, + 0.459 + ], + "angle": 0, + "content": "[13] Gregory Cohen, Saeed Afshar, Jonathan Tapson, and Andre Van Schaik. Emmist: Extending mnist to handwritten letters. In IJCNN, 2017. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.461, + 0.892, + 0.489 + ], + "angle": 0, + "content": "[14] Julia Collins and Johannes Zimmer. An asymmetric arzelà-ascoli theorem. Topology and its Applications, 2007. 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.49, + 0.892, + 0.532 + ], + "angle": 0, + "content": "[15] Jean-Antoine Désideri. Multiple-gradient descent algorithm (mgda) for multiobjective optimization. Comptes Rendus Mathematique, 2012. 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.533, + 0.892, + 0.574 + ], + "angle": 0, + "content": "[16] Prithviraj Dhar, Rajat Vikram Singh, Kuan-Chuan Peng, Ziyan Wu, and Rama Chellappa. Learning without memorizing. In CVPR, 2019. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.576, + 0.892, + 0.616 + ], + "angle": 0, + "content": "[17] Mehrdad Farajtabar, Navig Azizan, Alex Mott, and Ang Li. Orthogonal gradient descent for continual learning. In AISTATS, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.617, + 0.892, + 0.645 + ], + "angle": 0, + "content": "[18] MA Fiol. On pseudo-distance-regularity. Linear Algebra and its Applications, 2001. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.647, + 0.892, + 0.673 + ], + "angle": 0, + "content": "[19] Robert M French. Catastrophic forgetting in connectionist networks. TiCS, 1999. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.676, + 0.892, + 0.716 + ], + "angle": 0, + "content": "[20] Rick Groenendijk, Sezer Karaoglu, Theo Gevers, and Thomas Mensink. Multi-loss weighting with coefficient of variations. In WACV, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.718, + 0.892, + 0.772 + ], + "angle": 0, + "content": "[21] Yunhui Guo, Mingrui Liu, Tianbao Yang, and Tajana Rosing. Learning with long-term remembering: Following the lead of mixed stochastic gradient. arXiv preprint arXiv:1909.11763, 2019. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.774, + 0.892, + 0.815 + ], + "angle": 0, + "content": "[22] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, 2016. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.817, + 0.892, + 0.857 + ], + "angle": 0, + "content": "[23] Ali Jalali, Sujay Sanghavi, Chao Ruan, and Pradeep Ravikumar. A dirty model for multi-task learning. In NeurIPS, 2010. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.859, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[24] Adrián Javaloy and Isabel Valera. Rotograd: Gradient homogenization in multitask learning. arXiv preprint arXiv:2103.02631, 2021. 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "11419" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.472, + 0.161 + ], + "angle": 0, + "content": "[25] James Kirkpatrick, Razvan Pascanu, Neil Rabinowitz, Joel Veness, Guillaume Desjardins, Andrei A Rusu, Kieran Milan, John Quan, Tiago Ramalho, Agnieszka Grabska-Barwinska, et al. Overcoming catastrophic forgetting in neural networks. PNAS, 2017. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.162, + 0.471, + 0.19 + ], + "angle": 0, + "content": "[26] Ya Le and Xuan Yang. Tiny imagenet visual recognition challenge. CS 231N, 2015. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.19, + 0.472, + 0.217 + ], + "angle": 0, + "content": "[27] Zhizhong Li and Derek Hoiem. Learning without forgetting. TPAMI, 2017. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.218, + 0.471, + 0.259 + ], + "angle": 0, + "content": "[28] Baijiong Lin, Feiyang Ye, and Yu Zhang. A closer look at loss weighting in multi-task learning. arXiv preprint arXiv:2111.10603, 2021. 2, 4, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.26, + 0.471, + 0.3 + ], + "angle": 0, + "content": "[29] Bo Liu, Xingchao Liu, Xiaojie Jin, Peter Stone, and Qiang Liu. Conflict-averse gradient descent for multi-task learning. In NeurIPS, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.301, + 0.471, + 0.342 + ], + "angle": 0, + "content": "[30] Shikun Liu, Edward Johns, and Andrew J Davison. End-to-end multi-task learning with attention. In CVPR, 2019. 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.343, + 0.471, + 0.383 + ], + "angle": 0, + "content": "[31] David Lopez-Paz and Marc'Aurelio Ranzato. Gradient episodic memory for continual learning. In NeurIPS, 2017. 1, 2, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.385, + 0.471, + 0.427 + ], + "angle": 0, + "content": "[32] Fan Lyu, Shuai Wang, Wei Feng, Zihan Ye, Fuyuan Hu, and Song Wang. Multi-domain multi-task rehearsal for lifelong learning. In AAAI, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.427, + 0.471, + 0.468 + ], + "angle": 0, + "content": "[33] Arun Mallya, Dillon Davis, and Svetlana Lazebnik. Piggyback: Adapting a single network to multiple tasks by learning to mask weights. In ECCV, 2018. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.469, + 0.471, + 0.51 + ], + "angle": 0, + "content": "[34] Andreas Maurer, Massi Pontil, and Bernardino Romero-Paredes. Sparse coding for multitask and transfer learning. In ICML, 2013. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.511, + 0.471, + 0.539 + ], + "angle": 0, + "content": "[35] Andrea CG Mennucci. On asymmetric distances. Analysis and Geometry in Metric Spaces, 2013. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.539, + 0.471, + 0.58 + ], + "angle": 0, + "content": "[36] Jary Pomponi, Simone Scardapane, and Aurelio Uncini. Pseudo-rehearsal for continual learning with normalizing flows. arXiv preprint arXiv:2007.02443, 2020. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.58, + 0.471, + 0.622 + ], + "angle": 0, + "content": "[37] Liu Risheng, Liu Yaohua, Zeng Shangzhi, and Jin Zhang. Gradient-based editing of memory examples for online task-free continual learning. In NeurIPS, 2021. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.622, + 0.471, + 0.651 + ], + "angle": 0, + "content": "[38] Amir Rosenfeld and John K Tsotsos. Incremental learning through deep adaptation. TPAMI, 2018. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.651, + 0.471, + 0.705 + ], + "angle": 0, + "content": "[39] Andrei A Rusu, Neil C Rabinowitz, Guillaume Desjardins, Hubert Soyer, James Kirkpatrick, Koray Kavukcuoglu, Razvan Pascanu, and Raia Hadsell. Progressive neural networks. arXiv preprint arXiv:1606.04671, 2016. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.706, + 0.471, + 0.734 + ], + "angle": 0, + "content": "[40] Ozan Sener and Vladlen Koltun. Multi-task learning as multi-objective optimization. In NeurIPS, 2018. 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.734, + 0.471, + 0.775 + ], + "angle": 0, + "content": "[41] Haseeb Shah, Khurram Javed, and Faisal Shafait. Distillation techniques for pseudo-rehearsal based incremental learning. arXiv preprint arXiv:1807.02799, 2018. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.776, + 0.471, + 0.816 + ], + "angle": 0, + "content": "[42] Donald Shenaj, Marco Toldo, Alberto Rigon, and Pietro Zanuttigh. Asynchronous federated continual learning. In CVPR, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.471, + 0.858 + ], + "angle": 0, + "content": "[43] Qing Sun, Fan Lyu, Fanhua Shang, Wei Feng, and Liang Wan. Exploring example influence in continual learning. *NeurIPS*, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.859, + 0.471, + 0.899 + ], + "angle": 0, + "content": "[44] Sebastian Thrun and Joseph O'Sullivan. Discovering structure in multiple learning tasks: The tc algorithm. In ICML, 1996. 2" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.472, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.092, + 0.892, + 0.121 + ], + "angle": 0, + "content": "[45] Jie Wang and Jieping Ye. Safe screening for multi-task feature learning with multiple data matrices. In ICML, 2015. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.122, + 0.894, + 0.177 + ], + "angle": 0, + "content": "[46] Zirui Wang, Yulia Tsvetkov, Orhan Firat, and Yuan Cao. Gradient vaccine: Investigating and improving multi-task optimization in massively multilingual models. arXiv preprint arXiv:2010.05874, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.179, + 0.892, + 0.207 + ], + "angle": 0, + "content": "[47] Wallace Alvin Wilson. On quasi-metric spaces. American Journal of Mathematics, 1931. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.208, + 0.892, + 0.248 + ], + "angle": 0, + "content": "[48] Jaehong Yoon, Wonyong Jeong, Giwoong Lee, Eunho Yang, and Sung Ju Hwang. Federated continual learning with weighted inter-client transfer. In ICML, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.25, + 0.892, + 0.291 + ], + "angle": 0, + "content": "[49] Jaehong Yoon, Eunho Yang, Jeongtae Lee, and Sung Ju Hwang. Lifelong learning with dynamically expandable networks. arXiv preprint arXiv:1708.01547, 2017. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.293, + 0.892, + 0.335 + ], + "angle": 0, + "content": "[50] Tianhe Yu, Saurabh Kumar, Abhishek Gupta, Sergey Levine, Karol Hausman, and Chelsea Finn. Gradient surgery for multi-task learning. In NeurIPS, 2020. 1, 2, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.336, + 0.892, + 0.364 + ], + "angle": 0, + "content": "[51] Friedemann Zenke, Ben Poole, and Surya Ganguli. Continual learning through synaptic intelligence. In ICML, 2017. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.365, + 0.892, + 0.392 + ], + "angle": 0, + "content": "[52] Yu Zhang and Qiang Yang. A survey on multi-task learning. IEEE TKDE, 2021. 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.092, + 0.894, + 0.392 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "11420" + } + ] +] \ No newline at end of file diff --git a/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/e2e81f44-6f94-4699-81e2-292ae5d4c0a8_origin.pdf b/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/e2e81f44-6f94-4699-81e2-292ae5d4c0a8_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..8a50634dc1b77518da4186972be192feff0ec266 --- /dev/null +++ b/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/e2e81f44-6f94-4699-81e2-292ae5d4c0a8_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:f230d9c523eff143968ecb6f6df8639ba5eff0382ab3df7b933b8891ef211b30 +size 1138202 diff --git a/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/full.md b/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/full.md new file mode 100644 index 0000000000000000000000000000000000000000..16f440729e3e0b92942404e011dda2492b8e04f2 --- /dev/null +++ b/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/full.md @@ -0,0 +1,338 @@ +# Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning + +Fan Lyu, Qing Sun, Fanhua Shang, Liang Wan, Wei Feng* +College of Intelligence and Computing, Tianjin University + +{fanlyu, sssunqing, fhshang, lwan}@tju.edu.cn, wfeng@ieee.org + +# Abstract + +In Parallel Continual Learning (PCL), the parallel multiple tasks start and end training unpredictably, thus suffering from both training conflict and catastrophic forgetting issues. The two issues are raised because the gradients from parallel tasks differ in directions and magnitudes. Thus, in this paper, we formulate the PCL into a minimum distance optimization problem among gradients and propose an explicit Asymmetric Gradient Distance (AGD) to evaluate the gradient discrepancy in PCL. AGD considers both gradient magnitude ratios and directions, and has a tolerance when updating with a small gradient of inverse direction, which reduces the imbalanced influence of gradients on parallel task training. Moreover, we present a novel Maximum Discrepancy Optimization (MaxDO) strategy to minimize the maximum discrepancy among multiple gradients. Solving by MaxDO with AGD, parallel training reduces the influence of the training conflict and suppresses the catastrophic forgetting of finished tasks. Extensive experiments validate the effectiveness of our approach on three image recognition datasets in task-incremental and class-incremental PCL. Our code is available at https://github.com/fanlyu/maxdo. + +# 1. Introduction + +Continual Learning (CL) [25, 27, 31, 43], aims to continuously learn new knowledge from a sequence of tasks with non-overlapping data streams over a lifelong time. In the era of Internet of Things, people are using many smart devices, where multi-source data and tasks would be accessed at any time. A CL system should respond to parallel data streams from multiple devices. We study Parallel Continual Learning (PCL), as shown in Fig. 1, where an unfixed number of tasks are trained in a parallel way at any time. Specifically, according to the access time of each task, PCL builds an adaptive number of parallel data pipes, thus enabling instant response to new-coming tasks without pending. + +Due to the parallel data streams from different tasks, PCL suffers from not only the catastrophic forgetting but the training conflict among parallel tasks. Most existing methods in CL are proposed to tackle the catastrophic forgetting [19, 25], including regularization-based [25, 8, 16, 51, 1], rehearsal-based [31, 9, 21, 4, 41, 36], and architecture-based [33, 49, 39, 38] methods. In PCL, the training processes of different tasks are diverse, i.e., each task starts and ends training unpredictably (see Fig. 1). Thereby the gradient from different task differs in direction and magnitude [50] and may be neutralized. The gradient discrepancies lead to catastrophic forgetting and training conflict issues, which may fail the learning of some tasks. At any time in PCL, therefore, we present that the problem can be formulated to find an optimal gradient in a minimum distance multi-objective optimization, where each objective is to minimize the distance to a target gradient. In general, the distance metric is proportional to the effect of the optimal gradient on the corresponding task. + +In most situations, the mentioned distance metric $D$ between gradients is set to symmetric intuitively, such as the Euclidean distance and cosine distance. In other words, we usually have $D(\mathbf{x},\mathbf{y}) = D(\mathbf{y},\mathbf{x})$ for any $\mathbf{x}$ and $\mathbf{y}$ . However, the gradient influence is imbalanced among parallel tasks in the gradient descent. For example, in Fig. 1, at the marked time, we have three gradients with diverse directions and magnitudes, and updating with any of them provides different influences to the other two. In the minimum distance problem, the optimal solution should have the minimum negative influence on all parallel tasks, but using symmetric metrics means the influences are optimized indistinguishably at the same time. Due to the fact that the gradients are with wide differences, the solution may have large biases, which would get the near-fitting task out of its local minimum but has less impact on a new-coming task. + +To measure the gradient discrepancy, we hold the opinion that the distance metric in the min-distance problem should be asymmetric. First, though the metric is bound up with both the gradient magnitude and direction, the influences on model training from gradients should be asymmetric, where the model should have more tolerance to small gradients even if they indicate an inverse direction. Second, because + +![](images/a910f8f9e525de354fa547a0395dbe3623eb2180fd906b4c69b63ea8fa3b0ecd.jpg) +Parallel Continual Learning + +![](images/3dcbca57a3c25f08a3d55998fdd48e2695f8125929ec84d25d5c7d4d79c63141.jpg) +Gradient Discrepancy +Figure 1. Overview of the proposed method in PCL. Left: PCL trains parallel tasks according to their access time without pending. Middle: At any time, gradients from different tasks (corresponding colors) have unpredicted direction and magnitude (the length of vectors). Right: We formulate PCL into a min-distance problem and propose an asymmetric distance for effective optimization. + +![](images/583f6a4cdd92d1fbd35fa1ca0c5854137020753c6baf70de6a5ca8d57ec47c1f.jpg) +Minimize Asymmetric Distance + +gradients are with different magnitudes, the discrepancy between two large gradients is often set to larger than that between small gradients when using symmetric distance, such as Euclidean distance. Directly optimizing using magnitude-aware distance values may lead to the solution close to large gradients and thus hinder the kepping of old tasks. To mitigate the bias from the magnitude difference, it is better to employ the magnitude ratio instead of magnitude itself. + +Motivated by this, in this paper, we propose an explicit measurement for the learning from gradient discrepancy in PCL, named Asymmetric Gradient Distance (AGD), which considers gradient magnitude ratios and directions, and sets a tolerance for smaller gradients. As shown in Fig. 1, the proposed AGD is used in solving the minimum distance problem with multiple gradients from parallel tasks. Then, we propose an effective optimization strategy for minimizing the gradient discrepancy to avoid self-interference. We name the strategy Maximum Discrepancy Optimization (MaxDO), which minimizes the maximum discrepancy from each gradient to the others. Moreover, to address the catastrophic forgetting issue, we follow the rehearsal strategy [31] in traditional CL and build an extra memory data stream. The rehearsal data stream is used to provide a gradient of finished tasks in MaxDO. Solving by MaxDO with AGD, parallel training mitigates the impacts of the diverse training process and slows the catastrophic forgetting of finished tasks. Extensive results on three datasets show the superiority and effectiveness of our approach. + +Our main contributions are three-fold: + +(1) We formulate the PCL into a minimum distance problem and compare symmetric and asymmetric distances. We show that symmetric metrics are not effective in solving the problem and suggest asymmetric metrics. +(2) We propose an asymmetric metric, named AGD, to evaluate the gradient discrepancy, which is proportional to the gradient magnitude ratios and directions. AGD measures the imbalance of gradient influence in PCL. +(3) We propose MaxDO for minimizing gradient discrepancy of different tasks, which maximally reduces the + +asymmetric discrepancy from a gradient to the others. MaxDO avoids the self-interference among gradients and reduces training conflict and catastrophic forgetting. + +# 2. Related Work + +# 2.1. Continual Learning + +Continual Learning (CL) represents receiving data from new domains continually. In traditional CL, the new domains show up one by one, say serial CL. CL methods can be classified into three kinds. (1) Rehearsal [31, 9, 21, 4, 41, 36, 32], which saves or generates data of old tasks for retraining together with the current training. (2) Regularization [25, 8, 16, 51, 1, 17], which leverages extra regularization terms to consolidate previous knowledge when learning new tasks. (3) Dynamic architecture [33, 49, 39, 38], which freezes task-specific parameters and grows new branches for new tasks automatically. However, most of the existing CL methods are designed for reducing catastrophic forgetting in the serial scenario. Contrastively, in PCL, we need to tackle not only catastrophic forgetting but training conflict among parallel tasks, which is somehow related to multi-task learning. + +# 2.2. Multi-Task Learning + +Multi-Task Learning (MTL) [7] is used to address multiple tasks with a single model from one to many domains. Traditional MTL solutions can be mainly grouped into feature-based and parameter-based approaches [52]. The feature-based approaches focus on learning common feature representations for multiple tasks [34, 45]. The parameter-based approaches use model parameters in a task to help learn model parameters in other tasks [44, 5, 23]. Recently, some MTL methods propose to find an optimal gradient for updating and can be categorized into three types. (1) Learning-based methods [11], which learn a set of weights by backpropagation. (2) Solving-based methods [40, 29], solve the problem by finding an optimal gradient that is not dominated by the gradient from any task. (3) Calculating-based methods [30, 24, 12, 46, 50, 20, 28] compute the gradient weights + +by combining gradients or losses of all tasks. Inspired by MTL, we also formulate the problem into finding an optimal gradient. Specifically, we consider that the optimal gradient should have a small distance to all gradients. + +# 2.3. Asymmetric Metric + +In most situations in neural network, the distance is set to symmetric, e.g., the Euclidean distance. However, the symmetric metric is not always suitable for finding the optimal gradient (see the next section for details). Asymmetric metric [14, 35], also known as quasi-metric [14] or pseudo metric [18, 6], is a generalization of a metric but the symmetry axiom is eliminated in the definition of metric spaces. A classical example of asymmetric metric is the taxicab geometry topology including one-way streets, where a path from point A to B has different streets compared to a path from B to A. In this paper, we propose to measure the gradient discrepancy using an asymmetric metric and raise a novel optimization strategy to minimize the maximum discrepancy. + +# 3. Our Approach + +# 3.1. Parallel Continual Learning + +On a timeline, given a sequence of $T$ tasks with parallel data streams $\{\mathcal{D}_1,\dots ,\mathcal{D}_T\}$ for continual training, and each data stream can be accessed and suspended at any time. For simplest, we assume each data stream is i.i.d., and tasks are accessed in order from 1 to $T$ and there exists no real gap that no data stream flows on the timeline. Note that traditional CL is an edge situation of PCL that all tasks are nose-to-tail. A PCL model contains a shared backbone with parameter $\theta$ to learn task-agnostic knowledge and adaptively incremental number of task-specific classifiers with parameters $\theta_{i}$ . When a new task is accessed, a corresponding task-specific classifier will be constructed. + +In PCL, a task will be forgotten by learning any other tasks when its data stream ends. To avoid forgetting, we leverage the popular rehearsal strategy [31, 9, 21, 4, 41, 36] in our training. Rehearsal builds an extra data stream sampled from all seen tasks and retrans them to suppress the forgetting of finished tasks. For convenience, we denote the rehearsal data stream as $\mathcal{D}_0$ . At time $t$ , we use $\mathcal{T}_t$ to represent the activated data streams (including $\mathcal{D}_0$ ). Together with the rehearsal data stream, PCL training yields the following dynamic multi-objective empirical risk minimization: + +$$ +\min _ {\boldsymbol {\theta}, \left\{\boldsymbol {\theta} _ {i} \mid i \in \mathcal {T} _ {t} \right\}} \quad \left\{\ell_ {i} \left(\mathcal {D} _ {i}\right) \mid i \in \mathcal {T} _ {t} \right\}. \tag {1} +$$ + +Because the task-specific classifiers are updated by their own gradients $\theta_{i}\gets \theta_{i} - \alpha_{i}\nabla_{\theta_{i}}\ell_{i}$ $(\forall i\in T_{t})$ with step size $\alpha_{i}$ , we focus on the update of the shared backbone $\pmb{\theta}$ . At any PCL step, the goal of dynamic MOO is to optimize multiple objectives simultaneously while updating only once, and + +the only update of the shared parameters depends on the gradients of all in-training tasks. It will exit an uncertain number of tasks, and each task will provide a task-specific gradient on the shared parameter $\theta$ . Let $\mathbf{g}_i = \nabla_\theta \ell_i$ and $\alpha$ be a step size for optimization. The problem of the backbone update can be formulated as follows: + +$$ +\boldsymbol {\theta} \leftarrow \boldsymbol {\theta} - \alpha \mathbf {d} ^ {*}, \quad \text {w h e r e} \mathbf {d} ^ {*} = f \left(\left\{\mathbf {g} _ {i} | \forall i \in \mathcal {T} _ {t} \right\}\right). \tag {2} +$$ + +The key question is how to compute the optimal gradient $\mathbf{d}^*$ via the function $f(\cdot)$ . In this paper, we define the function $f(\cdot)$ as a min-distance multi-objective problem by minimizing the gradient distance from all in-training tasks: + +$$ +\mathbf {d} ^ {*} = \arg \min _ {\mathbf {d}} \quad \left\{D \left(\mathbf {d}, \mathbf {g} _ {i}\right) \mid \forall i \in \mathcal {T} \right\}, \tag {3} +$$ + +where we need to identify what distance metric $D$ is used to measure gradient discrepancy. The motivation of Eq. (3) is that for the task $i$ in PCL, its own gradient $\mathbf{g}_i$ is the most qualified update direction for itself. The solution $\mathbf{d}^*$ should be as close to every gradient as possible. + +A related but different task is Federated Continual Learning (FCL) [48, 42]. Most FCL methods primarily focus on serial training, involving multiple clients in training a shared task at the same time. It is meaningful to study Federated PCL in the future for the advancement of privacy protection. + +# 3.2. Measuring Asymmetric Gradient Discrepancy + +To measure gradient discrepancy, the Euclidean Distance (EuDist, $D(\mathbf{x},\mathbf{y}) = \| \mathbf{x} - \mathbf{y}\| \in [0,\infty)$ ) and Cosine Distance (CosDist, $D(\mathbf{x},\mathbf{y}) = 1 - \frac{\mathbf{x}^\top\mathbf{y}}{\|\mathbf{x}\|\|\mathbf{y}\|} \in [0,2]$ ) are the two most popular choices. Both of them are symmetric, i.e., $D(\mathbf{x},\mathbf{y}) = D(\mathbf{y},\mathbf{x})$ . A symmetric metric $D(\mathbf{x},\mathbf{y})$ means the forward influence ( $\mathbf{x}$ to $\mathbf{y}$ ) and backward influence ( $\mathbf{y}$ to $\mathbf{x}$ ) are equal. For example, given two in-training tasks A and B, the distance $D(\mathbf{g}_{\mathrm{A}},\mathbf{g}_{\mathrm{B}})$ represents both the effect of $\mathbf{g}_{\mathrm{A}}$ on task B and $\mathbf{g}_{\mathrm{B}}$ on task A because of $D(\mathbf{g}_{\mathrm{A}},\mathbf{g}_{\mathrm{B}}) = D(\mathbf{g}_{\mathrm{B}},\mathbf{g}_{\mathrm{A}})$ . Note that large distance from $\mathbf{g}_{\mathrm{A}}$ to $\mathbf{g}_{\mathrm{B}}$ means large negative influence on the training of task B with $\mathbf{g}_{\mathrm{A}}$ . + +However, the model update is highly related to gradient magnitude and direction, which are asymmetric to model updating. The influence of the gradient $\mathbf{g}_{\mathrm{A}}$ on task B may be quite different from that of the gradient $\mathbf{g}_{\mathrm{B}}$ on task A. In previous studies [31, 9, 50], the two tasks are treated as conflict when $\langle \mathbf{g}_{\mathrm{A}}, \mathbf{g}_{\mathrm{B}} \rangle < 0$ . In PCL, due to the diverse training process, gradients from parallel tasks are diverse in magnitude and direction. When $\| \mathbf{g}_{\mathrm{A}} \| \ll \| \mathbf{g}_{\mathrm{B}} \|$ , the gradient $\mathbf{g}_{\mathrm{A}}$ will have little negative influence on task B even if $\langle \mathbf{g}_{\mathrm{A}}, \mathbf{g}_{\mathrm{B}} \rangle < 0$ ; when $\| \mathbf{g}_{\mathrm{A}} \| \gg \| \mathbf{g}_{\mathrm{B}} \|$ (e.g., a new task A is accessed when task B has been trained for some time near convergence), the update produces huge impact on task B even if $\langle \mathbf{g}_{\mathrm{A}}, \mathbf{g}_{\mathrm{B}} \rangle > 0$ . Using traditional symmetric distances can hardly represent the asymmetric update influence difference. + +To effectively measure gradient discrepancy in PCL, we introduce the asymmetric metric. + +![](images/d817f0f7b570a583e20f971b61ee404f8f1aefd9e24ae6a902284e7b51e1bbbe.jpg) +(a) $z = 1 - \frac{\mathbf{x}^{\mathrm{T}}\mathbf{y}}{||\mathbf{x}||||\mathbf{y}||}$ + +![](images/b6afae9c4b7b9f2ba22ae0b15e703ef6ba7047b34c5ed44aa2745f734392ce7e.jpg) +(b) $z = \| \mathbf{x} - \mathbf{y}\|$ , $\| \mathbf{y}\| = 0.2$ +Figure 2. The measures of two gradient discrepancy from $\mathbf{x}$ to $\mathbf{y}$ . Note that the $x$ - and $y$ -axes are the angle (i.e., $\angle \mathbf{x}, \mathbf{y}$ ) between $\mathbf{x}$ and $\mathbf{y}$ , and the magnitude ratio $\frac{\|\mathbf{x}\|}{\|\mathbf{y}\|}$ , respectively. (a) Cosine distance; (b) Euclidean distance where $\|\mathbf{y}\| = 0.2$ as an example; (c) Asymmetric gradient distance. Please see Appendix for the contours. + +![](images/345811336273ba2622e3644d54005241be6d9bbb510a1dd1f32611206276f100.jpg) +(c) $z = \frac{\|\mathbf{x} - \mathbf{y}\|}{\|\mathbf{y}\| + \|\mathbf{x} - \mathbf{y}\|}$ + +Lemma 1 (Asymmetric Metric [14]) $D:\mathcal{X}\times \mathcal{X}\to \mathbb{R}$ is an asymmetric metric (a.k.a. quasi-metric [47]) if $D$ satisfies + +(1) $D(\mathbf{x},\mathbf{y})\geq 0$ and $\forall \mathbf{x}\in \mathbb{R}^d,D(\mathbf{x},\mathbf{x}) = 0;$ +(2) $D(\mathbf{x},\mathbf{z})\leq D(\mathbf{x},\mathbf{y}) + D(\mathbf{y},\mathbf{z}),\forall \mathbf{x},\mathbf{y},\mathbf{z}\in \mathbb{R}^{d}.$ + +The asymmetric metric does not require the symmetric property, i.e., $D(\mathbf{x}, \mathbf{y}) = D(\mathbf{y}, \mathbf{x})$ . Based on the definition, in this paper, we design an asymmetric metric to measure gradient discrepancy named Asymmetric Gradient Distance. + +# Definition 1 (Asymmetric Gradient Distance (AGD)) + +Given two gradient $\mathbf{g}_A$ and $\mathbf{g}_B$ , the asymmetric gradient distance is defined as + +$$ +\widehat {D} (\mathbf {g} _ {A}, \mathbf {g} _ {B}) = \left\{ \begin{array}{c l} 0 & , \quad i f \mathbf {g} _ {A} = \mathbf {g} _ {B} = \mathbf {0}, \\ \frac {\| \mathbf {g} _ {A} - \mathbf {g} _ {B} \|}{\| \mathbf {g} _ {B} \| + \| \mathbf {g} _ {A} - \mathbf {g} _ {B} \|}, & O t h e r w i s e. \end{array} \right. +$$ + +In Definition 1, we consider the edge situation when $\mathbf{g}_{\mathrm{A}} = \mathbf{g}_{\mathrm{B}} = \mathbf{0}$ to meet the definition of the asymmetric metric in Lemma 1. In AGD, gradient directions and magnitudes are considered. Instead of using gradient magnitude value difference, we use magnitude ratio difference to avoid the diverse training of different tasks in PCL. Therefore, we derive the corollary of the magnitude ratio: + +Corollary 1 $\widehat{D} (\mathbf{g}_A,\mathbf{g}_B)$ is an asymmetric metric and holds + +$$ +\lim_{\substack{\| \mathbf{g}_{A}\| \\ \| \mathbf{g}_{B}\| \to \infty}}\widehat{D} (\mathbf{g}_{A},\mathbf{g}_{B}) = 1,\quad \lim_{\substack{\| \mathbf{g}_{A}\| \\ \| \mathbf{g}_{B}\| \to 0}}\widehat{D} (\mathbf{g}_{A},\mathbf{g}_{B}) = \frac{1}{2}. +$$ + +We illustrate why AGD is qualified to evaluate the gradient discrepancy according to the definition and corollary. In Definition 1, we use AGD to represent the influence of $\mathbf{g}_{\mathrm{A}}$ on task B rather than the inverse. This is the key difference from the symmetric metrics such as Euclidean distance. Specifically, $\mathbf{g}_{\mathrm{A}}$ may make task B worse if $\widehat{D}(\mathbf{g}_{\mathrm{A}}, \mathbf{g}_{\mathrm{B}})$ is large (close + +to 1). If $\widehat{D}(\mathbf{g}_{\mathrm{A}}, \mathbf{g}_{\mathrm{B}})$ is close to 0, $\mathbf{g}_{\mathrm{A}}$ and $\mathbf{g}_{\mathrm{B}}$ has less conflict. Moreover, Corollary 1 involves that when $\|\mathbf{g}_{\mathrm{A}}\| \ll \|\mathbf{g}_{\mathrm{B}}\|$ , AGD has a tolerance $\frac{1}{2}$ even if $\langle \mathbf{g}_{\mathrm{A}}, \mathbf{g}_{\mathrm{B}} \rangle < 0$ , which means the impact of $\mathbf{g}_{\mathrm{A}}$ on task B is mild. This is because updating with a zero gradient will neither improve nor damage the performance. Even though, we prefer positive influence rather than non-influence. Thus, we define that the distance $\widehat{D}(\mathbf{g}_{\mathrm{A}}, \mathbf{g}_{\mathrm{B}})$ in this situation is the mid-level $(\frac{1}{2})$ in the value range([0,1]). See different tolerances in our experiments. + +Moreover, we compare AGD (Fig. 2(c)) with Euclidean and cosine distance in Fig. 2. First, the cosine distance (Fig. 2(a)) is magnitude irrelevant, which ignores the magnitude difference in PCL. Second, the Euclidean distance (Fig. 2(b)) depends heavily on the magnitude value difference, but ignores that the gradient influence on the model update is asymmetric. For example, when $\| \mathbf{x}\| \to 0$ , EuDist will get large if we have large $\| \mathbf{y}\|$ without any tolerance, which ignores the non-influence of zero gradient. + +# 3.3. Maximum Discrepancy Optimization + +At time $t$ , let the optimal solution to Problem (3) be $\mathbf{d}^*$ , where $\mathcal{T}_t$ is the index set of in-training tasks ( $\mathcal{T}$ for simplicity). However, directly optimizing the problem is difficult due to the large decision space that has the same dimension as $\pmb{\theta}$ . Following [28, 40], we use linear scalarization to solve the transformed problem that allows only optimizing decision variable $\mathbf{w} \in \mathbb{R}^{|\mathcal{T}|}$ . That is, let $\mathbf{d} = \sum_{i \in \mathcal{T}} \mathbf{w}_i \mathbf{g}_i$ , where $\forall \mathbf{w}_i \geq 0$ and $\sum_{i \in \mathcal{T}} \mathbf{w}_i = 1$ , we have + +$$ +\mathbf {w} ^ {*} = \underset {\mathbf {w}} {\arg \min } \quad \left\{\widehat {D} \left(\sum_ {j} \mathbf {w} _ {j} \mathbf {g} _ {j}, \mathbf {g} _ {i}\right) | \forall i \in \mathcal {T} \right\}. \tag {4} +$$ + +Each objective of the dual problem will be highly affected by the minimum discrepancy, i.e., each gradient itself. For example, by minimizing objective $\widehat{D} (\sum_{j}\mathbf{w}_{j}\mathbf{g}_{j},\mathbf{g}_{i})$ , weight $\mathbf{w}_i$ is more like to be activated than others. Thus, multiple + +![](images/86a186d1cdc01e2ac887d2d6f6b1e43f3672b64a687f052eca119106534c96f2.jpg) +Figure 3. Schematic of Maximum Discrepancy Optimization. Given multiple gradients $\{\mathbf{g}_i|\forall i\in \mathcal{T}\}$ $(|\mathcal{T}| = 4$ for example) (1) A weight matrix $\mathbf{W}$ is initialized with $\frac{1}{|\mathcal{T}|}$ for each entry. (2) For each row, the off-diagonal entries are used to weighted gradients and optimized for minimum AGD to the target gradient. (3) The diagonal entries $(\square)$ are used to optimize with min-norm with MGDA. (4) The final weight matrix is reduced by each column for the final weights $(w^{\prime})$ . See Sec. 3.3 for details. + +Algorithm 1: MaxDO ( ) in PCL +Input: Parameters $\theta ,\theta_{1:T}$ ; Step sizes $\alpha$ $\alpha_{1:T}$ Output: $\theta ,\theta_{1:T}$ +1 for t in timeline do +2 $\mathcal{T}_t\gets$ in-training task index; +3 for $i\in \mathcal{T}_t$ do +4 $\begin{array}{r}\mathcal{B}_i\sim \mathcal{D}_i;\\ \pmb {\theta}_i\gets \pmb {\theta}_i - \alpha_i\nabla_{\pmb{\theta}_i}\ell_i(\mathcal{B}_i);\\ \mathbf{g}_i = \nabla_\theta \ell_i(\mathcal{B}_i); \end{array}$ +5 +6 end +7 W\* Optimization by Eq. (5); d\* Final graident from Eq. (6); +8 +9 $\theta \leftarrow \theta -\alpha \mathbf{d}^{*};$ + +objectives will be compromised by multiple self-interference but fail to reduce the maximum discrepancy in the dual problem optimization. + +As shown in Fig. 3, we propose Maximum Discrepancy Optimization (MaxDO) to reduce the maximum gradient discrepancy. Specifically, instead of the weight vector $\mathbf{w} \in \mathbb{R}^{|\mathcal{T}|}$ , we optimize a weight matrix $\mathbf{W} \in \mathbb{R}^{|\mathcal{T}| \times |\mathcal{T}|}$ in which $\forall \mathbf{W}_{ij} \geq 0$ . $\mathbf{W}$ can be combined by a diagonal vector $\dot{\mathbf{w}} = [\mathbf{W}_{1,1}, \dots, \mathbf{W}_{|\mathcal{T}|,|\mathcal{T}|}]$ and an off-diagonal matrix $\widetilde{\mathbf{W}} = \mathbf{W} - \mathrm{Diag}(\dot{\mathbf{w}})$ , where $\sum_{i \in \mathcal{T}} \dot{\mathbf{w}}_i = 1$ and $\sum_{j \in \mathcal{T}} \widetilde{\mathbf{W}}_{ij} = 1, \forall i$ . Thus, $\sum_{i,j \in \mathcal{T}} \mathbf{W}_{ij} = |\mathcal{T}| + 1$ and the two weights are independent and can be optimized without disturbance as follows: (1) $\widetilde{\mathbf{W}}$ , computed by Stochastic Gradient Descent (SGD), is used to make up the maximum gradient discrepancy. The objectives of any two rows in $\widetilde{\mathbf{W}}$ are different. For row $i$ , to formulate the maximum discrepancy of gradient $\mathbf{g}_i$ , the objective is the combina + +tion of non-diagonal entries. The weighted other gradients should be with the smallest asymmetric distance to $\mathbf{g}_i$ . (2) $\dot{\mathbf{w}}$ is obtained by the Multiple Gradient Descent Algorithm (MGDA) [15], which is to obtain a weighted gradient that does not damage any tasks with a min-norm optimization. The objective of MGDA is 0 and the resulting point satisfies the Karush-Kuhn-Tucker condition or the solution gives a Pareto descent direction that improves all tasks. See Appendix for more details of MGDA. For each off-diagonal entry of the $i$ -th column, their sum means the effect of the gradient $\mathbf{g}_i$ reducing the maximum discrepancy from other gradients. MGDA is used to reduce the possible negative effect in MaxDO. On the other hand, MaxDO reduces the training failure of new tasks in MGDA. To sum up, our MaxDO with AGD can be computed by + +$$ +\mathbf {W} ^ {*} = \underbrace {\arg \min _ {\widetilde {\mathbf {W}}} \sum_ {\forall i \in \mathcal {T}} \widehat {D} \left(\sum_ {j \neq i} \widetilde {\mathbf {W}} _ {i , j} \mathbf {g} _ {j} , \mathbf {g} _ {i}\right)} _ {\text {S G D w i t h M a x i m u m D i s c r e p a n c y}} + \operatorname {D i a g} \underbrace {\left(\underset {\dot {\mathbf {w}}} {\arg \min } \left\| \sum_ {j} \dot {\mathbf {w}} _ {j} \mathbf {g} _ {j} \right\|\right)} _ {\text {M G D A [ 1 5 ]}}. \tag {5} +$$ + +In Eq. (5), we can obtain an approximate solution by combining the closed-form solution and the iterative solution. Fig. 3 reveals the diagram of solving MaxDO. We project the solution of SGD onto the feasible set $(\sum_{i \neq j} \mathbf{W}_{ij} = 1)$ via softmax at each step in the multiple steps for fast convergence. First, we initialize all entries of $\mathbf{W}$ by $\frac{1}{|\mathcal{T}|}$ . Then, the off-diagonal matrix is used to minimize the maximum gradient discrepancy via SGD and the diagonal vector is optimized by min-norm. Finally, the final weights are reduced to a vector by dividing $|\mathcal{T}| + 1$ to guarantee that their sum + +is 1. Note that, MaxDO is implemented only when $|\mathcal{T}| > 1$ , i.e., multiple tasks are given at the current time. Otherwise, we have $\mathbf{d}^{*} = \mathbf{g}_{1}$ for the only current task 1. Thus, the final gradient $\mathbf{d}^{*}$ is computed by + +$$ +\mathbf {d} ^ {*} = \left\{ \begin{array}{l l} \mathbf {g} _ {1}, & | \mathcal {T} | = 1, \\ \sum_ {i} \left(\frac {1}{| \mathcal {T} | + 1} \sum_ {j} \mathbf {W} _ {j, i} ^ {*}\right) \mathbf {g} _ {i}, & | \mathcal {T} | > 1. \end{array} \right. \tag {6} +$$ + +The detailed algorithm is shown in Algorithm 1. With the rehearsal data stream, our algorithm learns a PCL model through a timeline. At the time $t$ on the timeline, given a mini-batch $\mathcal{B}$ from each data stream, we compute the corresponding gradients on shared and task-specific parameters. The task-specific parameters are updated directly and the gradients on the shared backbone are collected for computed the final updated gradient $\mathbf{d}$ . By using our MaxDO, we update the shared parameters $\theta$ with the optimal $\mathbf{d}^*$ . + +# 4. Experiment + +# 4.1. Dataset + +In our experiments, 3 traditional image recognition datasets are transformed into parallel data streams: (1) Parallel Split EMNIST (PS-EMNIST). We split EMNIST [13] (62 classes) into 5 tasks and the size of the label set for each task, i.e., the number of classes, is set to \{12, 12, 12, 13, 13\}. (2) Parallel Split CIFAR-100 (PS-CIFAR-100). We split CIFAR-100 into 10 tasks and the size of the label set for each task is set to 10. (3) Parallel Split ImageNet-TINY (PS-ImageNet-TINY). We split Tiny ImageNet [26] (200 classes) into 10 tasks, and the size of the label set for each task is set to 20. We evaluate PCL on task-incremental and class-incremental scenarios. Please see Appendix for more dataset details. + +All three datasets have 3 different label sets (3 different class splits), each of which has 3 different timelines (when to access). For each timeline, we have 3 different runs with fixed seeds 1234, 1235, and 1236 for parameter initialization. In other words, we have 27 different settings for each dataset, and we report the average and standard deviation (avg $\pm$ std) for each compared method in our experiments. Note that, we omit all blank time that no data stream flows for simplicity. + +# 4.2. Experiment Details + +We implement our experiments using Tensorflow and conduct on a single NVidia RTX 3090Ti GPU card. We take a 2-layer MLP as the backbone network for PS-EMNIST and a Resnet-18 [22] for PS-CIFAR-100 and PS-ImageNet-Tiny. The learning rate is set to 0.003, 0.0004 and 0.0005 for PS-EMNIST, PS-CIFAR-100 and PS-ImageNet-Tiny. The SGD in MaxDO has a learning rate of 5. Each task is trained in a data stream, i.e., each data point passes only once. For each + +![](images/1ae8de300461d0b1ceda8b92b66ef17a7b1dd0cee77b568ac8ba6ba7f66e7f75.jpg) +Figure 4. Different memory sizes on PS-CIFAR-100. + +![](images/4fff1c78cc545be1a217d1ffa6e29e7ae4fbebcde1ad6dcbb68e42c55236c811.jpg) + +task, we set the batch size to 128 per step. For any new task in PCL, we build a new classifier, which is a fully-connected layer with a softmax function. + +To evaluate PCL, we compute the average accuracy and forgetting, following previous continual learning studies [31, 9, 3, 2, 37]. Let $e_t$ be the end time of task $t$ and the final time $\bar{e} = \max(e_1, e_2, \dots, e_T)$ , the two metrics are computed as: + +$$ +A _ {\bar {e}} = \frac {1}{T} \sum_ {t = 1} ^ {T} a _ {\bar {e}} ^ {t}, \quad F _ {\bar {e}} = \frac {1}{T} \sum_ {t = 1} ^ {T} a _ {\bar {e}} ^ {t} - a _ {e _ {t}} ^ {t}, \tag {7} +$$ + +where $a_{k}^{j}$ is the mean testing accuracy of task $j$ at time $k$ . $A_{\bar{e}}$ denotes the final average accuracy on all the tasks, and $F_{\bar{e}}$ (also known as backward transfer) means the final performance drop compared to each task that was first trained. + +# 4.3. Main Results + +We compare our method with MTL methods including MGDA [15], GradNorm [11], DWA [30], GradDrop [12], PCGrad [50] and RLW [28] in the PCL setting. We treat any time on the timeline as an MTL subunit to train PCL. All results of previous MTL methods are produced by ourselves with the claimed design in their papers. We also compare with some rehearsal-based SCL methods including AGEM[9], GMED[37] and ER[10]. To adapt to the SCL methods, we merge batches from every in-training task to mimic a naive sequence learning that only a batch from the current task and a batch from the memory buffer. + +We show the main comparisons with the proposed methods in Tables 1 and 2 on the three datasets. We have several major observations. First, the rehearsal strategy is useful for reducing catastrophic forgetting in PCL for all compared methods. As an extra data stream apart from in-training data streams, rehearsal provides data from the finished tasks training together with other tasks to suppress forgetting. With the rehearsal strategy, the memory may provide continual learning of finished tasks, and even better performance can be obtained, which results in positive forgetting values on $F_{\bar{e}}$ . Second, without task-id, class-incremental PCL has worse performance than task-incremental PCL. Surprisingly, we find that MGDA has good performance than other methods in + +Table 1. Task-incremental comparisons (avg ± std) on 3 datasets. + +
Method (+ Reherasal)TypePS-EMNISTPS-CIFAR-100PS-ImageNet-TINY
A̅̅ (‰)F̅̅ (‰)A̅̅ (‰)F̅̅ (‰)A̅̅ (‰)F̅̅ (‰)
AvgGradMTL89.344 ± 0.231-5.287 ± 0.21647.579 ± 0.08923.691 ± 0.43238.392 ± 0.0760.764 ± 0.139
MGDA [15]MTL84.887 ± 0.469-4.301 ± 0.81848.957 ± 0.45125.088 ± 0.20338.058 ± 0.7401.465 ± 0.490
GradNorm [11]MTL87.888 ± 0.158-6.197 ± 0.18347.210 ± 1.32323.474 ± 0.68838.226 ± 0.7691.647 ± 0.667
DWA [30]MTL88.405 ± 0.322-5.452 ± 0.33844.969 ± 0.37822.682 ± 0.53734.290 ± 1.099-1.053 ± 0.866
PCGrad [50]MTL89.698 ± 0.164-4.921 ± 0.12147.026 ± 0.53823.244 ± 0.74039.427 ± 1.2752.017 ± 0.769
RLW [28]MTL89.288 ± 0.218-5.226 ± 0.20447.574 ± 0.34923.833 ± 0.11738.531 ± 1.6101.332 ± 1.148
AGEM [9]SCL87.022 ± 0.519-7.646 ± 0.48327.379 ± 0.5855.416 ± 0.85128.530 ± 0.994-7.070 ± 1.410
GMED [37]SCL85.471 ± 0.324-8.875 ± 0.33549.094 ± 1.79218.356 ± 1.34534.495 ± 1.568-0.640 ± 1.799
ER [10]SCL89.106 ± 0.315-5.525 ± 0.20747.324 ± 0.58423.330 ± 0.76235.950 ± 0.763-0.767 ± 0.591
MaxDO (AGD)PCL90.189 ± 0.314-4.258 ± 0.31150.203 ± 0.97824.510 ± 0.09240.770 ± 0.3543.119 ± 0.450
+ +Table 2. Class-incremental comparisons (avg $\pm$ std) on 3 datasets. + +
Method (+ Reherasal)TypePS-EMNISTPS-CIFAR-100PS-ImageNet-TINY
A̅e(%)F̅e(%)A̅e(%)F̅e(%)A̅e(%)F̅e(%)
AvgGradMTL43.823 ± 0.566-44.484 ± 0.5968.921 ± 0.276-4.985 ± 0.7027.511 ± 0.661-15.825 ± 0.228
MGDA [15]MTL52.823 ± 0.201-7.753 ± 0.53811.323 ± 0.282-4.065 ± 0.7258.318 ± 0.155-13.118 ± 0.739
GradNorm [11]MTL43.292 ± 0.590-44.824 ± 0.6889.477 ± 0.222-4.403 ± 1.2366.395 ± 0.130-15.869 ± 0.336
DWA [30]MTL42.734 ± 0.211-38.944 ± 0.5813.519 ± 0.116-7.470 ± 0.2443.003 ± 0.139-12.774 ± 0.158
PCGrad [50]MTL45.035 ± 0.273-43.309 ± 0.17610.140 ± 0.253-5.149 ± 0.5537.789 ± 0.237-15.860 ± 0.318
RLW [28]MTL44.595 ± 0.480-43.424 ± 0.3259.957 ± 0.135-5.173 ± 0.6137.419 ± 0.258-16.079 ± 0.255
AGEM [9]SCL26.249 ± 0.511-62.480 ± 0.5273.374 ± 0.098-10.462 ± 0.5433.379 ± 0.149-18.514 ± 0.516
GMED [37]SCL22.694 ± 0.153-65.805 ± 0.2554.941 ± 0.407-12.837 ± 0.7103.386 ± 0.348-19.060 ± 0.682
ER [10]SCL43.474 ± 0.860-44.597 ± 0.8619.317 ± 0.339-5.337 ± 0.6266.126 ± 0.277-13.686 ± 0.290
MaxDO (AGD)PCL53.139 ± 0.156-11.903 ± 0.47612.237 ± 0.176-2.280 ± 0.2709.532 ± 0.363-12.511 ± 0.610
+ +class-incremental PCL compared with the task-incremental scenario, which means the suppressing on catastrophic forgetting is more important in class-incremental PCL. Third, the compared MTL methods are designed for balanced training and ignore the diverse training process in PCL, thus some gradients may be counteracted because of the large gradient discrepancy when updating the model. In contrast, our MaxDO with AGD obtains the best final accuracy $A^T$ on three datasets and two scenarios, which shows our superiority in balancing plasticity and stability. For example, we have $40.770\%$ and $9.431\%$ for PS-ImageNet-TINY on two scenarios respectively, while the compared best value is only $39.427\%$ and $8.318\%$ . On one hand, the proposed AGD is used to measure the asymmetric distance between gradients to boost the effective update of each task. On the other hand, the maximum discrepancies between multiple tasks are reduced. Note that, the forgetting measure of the proposed methods may not outperform the compared methods because we got both better new tasks and final accuracy performance, their difference value may be small. + +# 4.4. Rehearsal Analysis in PCL + +In Fig. 4, we compare the effects of different memory buffer sizes (per class) in rehearsal on PS-CIFAR-100. We observe that the memory buffer size affects the remembering + +of old knowledge, and a larger size means better knowledge keeping, which is similar to traditional CL. Under the same memory size, our method has better performance. Then, in Table 3(a), to show the MaxDO's effectiveness of forgetting reduction on rehearsal gradient, we evaluate the result that only leverages MaxDO on new tasks. In this case, the final gradient is calculated by $\mathbf{d} = \frac{1}{2}\mathbf{g}_{\mathrm{reh}} + \frac{1}{2}\mathbf{g}_{\mathrm{new}}$ , where $\mathbf{g}_{\mathrm{new}}$ is the solution gradient via MaxDO on only new parallel tasks, and $\mathbf{g}_{\mathrm{reh}}$ means the gradient from the rehearsal data streams. The result shows that it is necessary to put the rehearsal gradient to the MaxDO. Otherwise, the model will get worse accuracy and forgetting. + +# 4.5. Comparison with Symmetric Metrics + +As shown in Table 3(b), we compare AGD with three common symmetric metrics including EuDist, CosDist, and Normalized EuDist. EuDist, CosDist are defined in Sec. 3.2. The vanilla EuDist depends highly on the gradient magnitude difference, thus we also compare with its normalized version $D(\mathbf{x},\mathbf{y}) = \frac{\|\mathbf{x} - \mathbf{y}\|}{\|\mathbf{x}\| + \|\mathbf{y}\|} \in [0,1]$ , namely normalized EuDist (Norm EuDist). The results show that the three metrics can also obtain good performance with MaxDO. However, EuDist fails to reduce catastrophic forgetting effectively because of the over-emphasizing of gradient magnitude difference. Considering only the gradient direction difference, MaxDO + +Table 3. Reherasal experiemtns, comparisons with symmetric metrics and ablation studies in MaxDO on PS-CIFAR-100. + +
ExperimentMethodTask-incrementClass-increment
A̅e(%)F̅e(%)A̅e(%)F̅e(%)
(a) Rehearsal analysisMaxDO (w/o Rehearsal)25.241 ± 0.4663.128 ± 0.1752.971 ± 0.048-11.356 ± 0.703
MaxDO (w/o Reheerasal gradient)47.653 ± 1.28023.538 ± 1.4689.431 ± 0.469-5.907 ± 0.658
(b) Symmetric metricsMaxDO (EuDist)49.201 ± 0.41024.112 ± 0.19710.189 ± 0.218-7.172 ± 0.796
MaxDO (CosDist)49.154 ± 0.57025.094 ± 0.22211.771 ± 0.139-3.114 ± 0.681
MaxDO (Norm EuDist)48.517 ± 0.33624.386 ± 0.38811.692 ± 0.373-3.228 ± 0.822
(c) Ablation studiesMGDA [15]48.957 ± 0.45125.088 ± 0.20311.323 ± 0.282-4.065 ± 0.725
MaxDO (w/o Max-Discrepancy)47.899 ± 1.02223.874 ± 0.44710.441 ± 0.324-4.807 ± 0.573
MaxDO (w/o MGDA)49.631 ± 0.43125.816 ± 0.56111.881 ± 0.468-2.993 ± 0.964
(d) Our full methodMaxDO (AGD, w/ Reherasal)50.203 ± 0.27424.510 ± 0.09212.237 ± 0.176-2.280 ± 0.270
+ +![](images/18d9405b8087426dcf15d0ca9fea6a247f6b347f5598f8ac4f42496dba9479d9.jpg) +(a) +Figure 5. Training time comparisons. + +![](images/5197341081d95afd38ac43bf1b27e759b29e2e5cba2c6a875248ef209fac8e1d.jpg) +(b) + +with CosDist obtains better performance than EuDist. But CosDist ignores the magnitude difference, which is also important in the min-distance problem, resulting in insufficient performance. Compared to EuDist, normalized EuDist obtains even worse performance. In contrast, MaxDO with AGD considers the asymmetric influence on gradient update, and tolerance is set to reduce the influence from small gradients to new-access tasks, which yields the best performance. + +# 4.6. Ablation Study + +We evaluate the impact of the two main components of MaxDO in Table 3(c). First, we block the maximum discrepancy in MaxDO (MaxDO (w/o Max-Discrepancy)), which means that we solve the min-distance problem with Eq. (4) directly. Because of the self-interference, the solution combines the minimum discrepancy but fails to effectively reduce the discrepancy from other gradients (47.899% and 10.441% for $A_{\bar{e}}$ ). We then block the MGDA that obtains a weighted gradient not damage any tasks. MGDA is quite useful in traditional MTL tasks but is not suitable in PCL (w/o MGDA, 49.693% and 11.881% for $A_{\bar{e}}$ ). Because of the diverse training process of parallel tasks, gradients are with large magnitude differences and MGDA prefers to set large factors to small gradients. We solve the problem by both MGDA and the maximum discrepancy, and the whole MaxDO method with AGD outperforms the two ablated + +methods (50.203% and 12.231% for $A_{\bar{e}}$ ), where the characters of the two components are combined. + +# 4.7. Procedure Time + +In Fig. 5, we show the training time comparison on PS-CIFAR-100. We first compare the training time for 2 to 5 parallel tasks in one iteration (Fig. 5(a)). We find that the generation of task numbers will grow the training time, and MaxDO needs more time than other methods because multiple minimum distance optimizations are performed. Then, we show both the final accuracy and whole training time in Fig. 5(b). In the whole timeline, MaxDO gets slightly longer training time than other methods but better performance. + +# 4.8. Tolerance Analysis in AGD + +In our paper, AGD is designed to have a tolerance $\frac{1}{2}$ in Corollary 1. This is because updating with a zero gradient will neither improve nor damage the performance. Even though, we prefer positive influence rather than noninfluence. Thus, we define that the distance $\widehat{D}(\mathbf{g}_{\mathrm{A}}, \mathbf{g}_{\mathrm{B}})$ in the situation $\|\mathbf{g}_{\mathrm{A}}\| \ll \|\mathbf{g}_{\mathrm{B}}\|$ is the mid-level in the value range. Therefore, we study to change the tolerance and observe the performance change. The tolerance can be controlled by adding a factor $\gamma > 0$ at the denominator. Omitting the edge situation, we have + +$$ +\widehat {D} _ {\gamma} \left(\mathbf {g} _ {\mathrm {A}}, \mathbf {g} _ {\mathrm {B}}\right) = \frac {\| \mathbf {g} _ {\mathrm {A}} - \mathbf {g} _ {\mathrm {B}} \|}{\gamma \| \mathbf {g} _ {\mathrm {B}} \| + \| \mathbf {g} _ {\mathrm {A}} - \mathbf {g} _ {\mathrm {B}} \Vert}. +$$ + +The experiments on different tolerances are shown in Table 4. The results show either larger or smaller tolerances compared to $\frac{1}{2}$ will get the performance drop during the PCL training. + +# 5. Conclusion + +In this paper, we studied to address the training conflict and catastrophic forgetting issues in Parallel Continual Learning (PCL). We presented that the two issues are rooted in the gradient discrepancies and formulated the problem into a minimum distance optimization among gradients. However, the distance metric is often set to be symmetric, which + +Table 4. Comparisons on different tolerance (Tol.). + +
γTol.Task-incrementClass-increment
A̅e(%)F̅e(%)A̅e(%)F̅e(%)
0.25/646.118 ± 0.46322.617 ± 0.48411.283 ± 0.696-3.158 ± 1.087
0.52/346.452 ± 0.11322.874 ± 0.68011.284 ± 0.343-3.305 ± 0.629
11/250.203 ± 0.27424.510 ± 0.09212.237 ± 0.176-2.280 ± 0.270
21/349.827 ± 0.42025.520 ± 0.61111.603 ± 0.506-3.503 ± 0.687
31/448.766 ± 0.17124.491 ± 0.40611.389 ± 0.738-3.234 ± 1.060
41/548.859 ± 0.62724.714 ± 0.43711.378 ± 0.484-3.189 ± 0.902
+ +is problematic in gradient descent. To evaluate the gradient discrepancy in PCL, we proposed an explicit Asymmetric Gradient Distance (AGD), which considers both gradient magnitude ratios and directions and has a tolerance when updating with a small gradient of inverse direction. Moreover, we proposed a novel Maximum Discrepancy Optimization (MaxDO) strategy to minimize the maximum discrepancy among multiple gradients and avoid self-interference. Solving by MaxDO with AGD, the parallel training in PCL reduces the influence of the training conflict and slows the catastrophic forgetting. We verified the proposed method on three image recognition datasets. The experimental results significantly showed the advantage of MaxDO and the effectiveness of the proposed AGD. We list the latent limitation of our method: (1) The MaxDO cannot guarantee a theoretical Pareto optimum in the training process like MGDA, which means a better trade-off can be obtained in the future. (2) The MaxDO method needs more time for training. + +# Acknowledgement + +We gratefully acknowledge the invaluable support from the following funding bodies: the National Natural Science Foundation of China (62072334, 62276182), and the National Key Research and Development Program of China (2020YFC1522701). + +# References + +[1] Rahaf Aljundi, Francesca Babiloni, Mohamed Elhoseiny, Marcus Rohrbach, and Tinne Tuytelaars. Memory aware synapses: Learning what (not) to forget. In ECCV, 2018. 1, 2 +[2] Rahaf Aljundi, Eugene Belilovsky, Tinne Tuytelaars, Laurent Charlin, Massimo Caccia, Min Lin, and Lucas Page-Caccia. Online continual learning with maximal interfered retrieval. In NeurIPS, 2019. 6 +[3] Rahaf Aljundi, Min Lin, Baptiste Goujaud, and Yoshua Bengio. Gradient based sample selection for online continual learning. In NeurlPS, 2019. 6 +[4] Craig Atkinson, Brendan McCane, Lech Szymanski, and Anthony Robins. Pseudo-rehearsal: Achieving deep reinforcement learning without catastrophic forgetting. arXiv preprint arXiv:1812.02464, 2018. 1, 2, 3 +[5] Aviad Barzilai and Koby Crammer. Convex multi-task learning by clustering. In AISTATS, 2015. 2 + +[6] Francesca Cagliari, Barbara Di Fabio, and Claudia Landi. The natural pseudo-distance as a quotient pseudo-metric, and applications. In Forum Mathematicum. De Gruyter, 2015. 3 +[7] Rich Caruana. Multitask learning. Machine learning, 1997. 2 +[8] Arslan Chaudhry, Puneet K Dokania, Thalaiyasingam Ajthan, and Philip HS Torr. Riemannian walk for incremental learning: Understanding forgetting and intransigence. In ECCV, 2018. 1, 2 +[9] Arslan Chaudhry, Marc'Aurelio Ranzato, Marcus Rohrbach, and Mohamed Elhoseiny. Efficient lifelong learning with a-gem. In ICLR, 2019. 1, 2, 3, 6, 7 +[10] Arslan Chaudhry, Marcus Rohrbach, Mohamed Elhoseiny, Thalaiyasingam Ajanthan, Puneet K Dokania, Philip H S Torr, and Marcurelio Ranzato. On tiny episodic memories in continual learning. arXiv: Learning, 2019. 6, 7 +[11] Zhao Chen, Vijay Badrinarayanan, Chen-Yu Lee, and Andrew Rabinovich. Gradnorm: Gradient normalization for adaptive loss balancing in deep multitask networks. In ICML, 2018. 2, 6, 7 +[12] Zhao Chen, Jiquan Ngiam, Yanping Huang, Thang Luong, Henrik Kretzschmar, Yuning Chai, and Dragomir Anguelov. Just pick a sign: Optimizing deep multitask models with gradient sign dropout. In NeurIPS, 2020. 2, 6 +[13] Gregory Cohen, Saeed Afshar, Jonathan Tapson, and Andre Van Schaik. Emmist: Extending mnist to handwritten letters. In IJCNN, 2017. 6 +[14] Julia Collins and Johannes Zimmer. An asymmetric arzelà-ascoli theorem. Topology and its Applications, 2007. 3, 4 +[15] Jean-Antoine Désideri. Multiple-gradient descent algorithm (mgda) for multiobjective optimization. Comptes Rendus Mathematique, 2012. 5, 6, 7, 8 +[16] Prithviraj Dhar, Rajat Vikram Singh, Kuan-Chuan Peng, Ziyan Wu, and Rama Chellappa. Learning without memorizing. In CVPR, 2019. 1, 2 +[17] Mehrdad Farajtabar, Navig Azizan, Alex Mott, and Ang Li. Orthogonal gradient descent for continual learning. In AISTATS, 2020. 2 +[18] MA Fiol. On pseudo-distance-regularity. Linear Algebra and its Applications, 2001. 3 +[19] Robert M French. Catastrophic forgetting in connectionist networks. TiCS, 1999. 1 +[20] Rick Groenendijk, Sezer Karaoglu, Theo Gevers, and Thomas Mensink. Multi-loss weighting with coefficient of variations. In WACV, 2021. 2 +[21] Yunhui Guo, Mingrui Liu, Tianbao Yang, and Tajana Rosing. Learning with long-term remembering: Following the lead of mixed stochastic gradient. arXiv preprint arXiv:1909.11763, 2019. 1, 2, 3 +[22] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, 2016. 6 +[23] Ali Jalali, Sujay Sanghavi, Chao Ruan, and Pradeep Ravikumar. A dirty model for multi-task learning. In NeurIPS, 2010. 2 +[24] Adrián Javaloy and Isabel Valera. Rotograd: Gradient homogenization in multitask learning. arXiv preprint arXiv:2103.02631, 2021. 2 + +[25] James Kirkpatrick, Razvan Pascanu, Neil Rabinowitz, Joel Veness, Guillaume Desjardins, Andrei A Rusu, Kieran Milan, John Quan, Tiago Ramalho, Agnieszka Grabska-Barwinska, et al. Overcoming catastrophic forgetting in neural networks. PNAS, 2017. 1, 2 +[26] Ya Le and Xuan Yang. Tiny imagenet visual recognition challenge. CS 231N, 2015. 6 +[27] Zhizhong Li and Derek Hoiem. Learning without forgetting. TPAMI, 2017. 1 +[28] Baijiong Lin, Feiyang Ye, and Yu Zhang. A closer look at loss weighting in multi-task learning. arXiv preprint arXiv:2111.10603, 2021. 2, 4, 6, 7 +[29] Bo Liu, Xingchao Liu, Xiaojie Jin, Peter Stone, and Qiang Liu. Conflict-averse gradient descent for multi-task learning. In NeurIPS, 2021. 2 +[30] Shikun Liu, Edward Johns, and Andrew J Davison. End-to-end multi-task learning with attention. In CVPR, 2019. 2, 6, 7 +[31] David Lopez-Paz and Marc'Aurelio Ranzato. Gradient episodic memory for continual learning. In NeurIPS, 2017. 1, 2, 3, 6 +[32] Fan Lyu, Shuai Wang, Wei Feng, Zihan Ye, Fuyuan Hu, and Song Wang. Multi-domain multi-task rehearsal for lifelong learning. In AAAI, 2021. 2 +[33] Arun Mallya, Dillon Davis, and Svetlana Lazebnik. Piggyback: Adapting a single network to multiple tasks by learning to mask weights. In ECCV, 2018. 1, 2 +[34] Andreas Maurer, Massi Pontil, and Bernardino Romero-Paredes. Sparse coding for multitask and transfer learning. In ICML, 2013. 2 +[35] Andrea CG Mennucci. On asymmetric distances. Analysis and Geometry in Metric Spaces, 2013. 3 +[36] Jary Pomponi, Simone Scardapane, and Aurelio Uncini. Pseudo-rehearsal for continual learning with normalizing flows. arXiv preprint arXiv:2007.02443, 2020. 1, 2, 3 +[37] Liu Risheng, Liu Yaohua, Zeng Shangzhi, and Jin Zhang. Gradient-based editing of memory examples for online task-free continual learning. In NeurIPS, 2021. 6, 7 +[38] Amir Rosenfeld and John K Tsotsos. Incremental learning through deep adaptation. TPAMI, 2018. 1, 2 +[39] Andrei A Rusu, Neil C Rabinowitz, Guillaume Desjardins, Hubert Soyer, James Kirkpatrick, Koray Kavukcuoglu, Razvan Pascanu, and Raia Hadsell. Progressive neural networks. arXiv preprint arXiv:1606.04671, 2016. 1, 2 +[40] Ozan Sener and Vladlen Koltun. Multi-task learning as multi-objective optimization. In NeurIPS, 2018. 2, 4 +[41] Haseeb Shah, Khurram Javed, and Faisal Shafait. Distillation techniques for pseudo-rehearsal based incremental learning. arXiv preprint arXiv:1807.02799, 2018. 1, 2, 3 +[42] Donald Shenaj, Marco Toldo, Alberto Rigon, and Pietro Zanuttigh. Asynchronous federated continual learning. In CVPR, 2023. 3 +[43] Qing Sun, Fan Lyu, Fanhua Shang, Wei Feng, and Liang Wan. Exploring example influence in continual learning. *NeurIPS*, 2022. 1 +[44] Sebastian Thrun and Joseph O'Sullivan. Discovering structure in multiple learning tasks: The tc algorithm. In ICML, 1996. 2 + +[45] Jie Wang and Jieping Ye. Safe screening for multi-task feature learning with multiple data matrices. In ICML, 2015. 2 +[46] Zirui Wang, Yulia Tsvetkov, Orhan Firat, and Yuan Cao. Gradient vaccine: Investigating and improving multi-task optimization in massively multilingual models. arXiv preprint arXiv:2010.05874, 2020. 2 +[47] Wallace Alvin Wilson. On quasi-metric spaces. American Journal of Mathematics, 1931. 4 +[48] Jaehong Yoon, Wonyong Jeong, Giwoong Lee, Eunho Yang, and Sung Ju Hwang. Federated continual learning with weighted inter-client transfer. In ICML, 2021. 3 +[49] Jaehong Yoon, Eunho Yang, Jeongtae Lee, and Sung Ju Hwang. Lifelong learning with dynamically expandable networks. arXiv preprint arXiv:1708.01547, 2017. 1, 2 +[50] Tianhe Yu, Saurabh Kumar, Abhishek Gupta, Sergey Levine, Karol Hausman, and Chelsea Finn. Gradient surgery for multi-task learning. In NeurIPS, 2020. 1, 2, 3, 6, 7 +[51] Friedemann Zenke, Ben Poole, and Surya Ganguli. Continual learning through synaptic intelligence. In ICML, 2017. 1, 2 +[52] Yu Zhang and Qiang Yang. A survey on multi-task learning. IEEE TKDE, 2021. 2 \ No newline at end of file diff --git a/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/images.zip b/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..9760bba40997527b1b0f31faf1f9172292924d16 --- /dev/null +++ b/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:3464e8e65b9cc1e0de1465abd26e742a755722e752e8034d4c6d2da1b8baab68 +size 690977 diff --git a/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/layout.json b/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..330210b88d2e6c7235e0b0ce2daa52e9cd1b4f04 --- /dev/null +++ b/2023/Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning/layout.json @@ -0,0 +1,10297 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 58, + 103, + 536, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 103, + 536, + 121 + ], + "spans": [ + { + "bbox": [ + 58, + 103, + 536, + 121 + ], + "type": "text", + "content": "Measuring Asymmetric Gradient Discrepancy in Parallel Continual Learning" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 170, + 143, + 439, + 172 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 170, + 143, + 439, + 172 + ], + "spans": [ + { + "bbox": [ + 170, + 143, + 439, + 172 + ], + "type": "text", + "content": "Fan Lyu, Qing Sun, Fanhua Shang, Liang Wan, Wei Feng* \nCollege of Intelligence and Computing, Tianjin University" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 132, + 174, + 462, + 186 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 132, + 174, + 462, + 186 + ], + "spans": [ + { + "bbox": [ + 132, + 174, + 462, + 186 + ], + "type": "text", + "content": "{fanlyu, sssunqing, fhshang, lwan}@tju.edu.cn, wfeng@ieee.org" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "spans": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 239, + 290, + 491 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 239, + 290, + 491 + ], + "spans": [ + { + "bbox": [ + 46, + 239, + 290, + 491 + ], + "type": "text", + "content": "In Parallel Continual Learning (PCL), the parallel multiple tasks start and end training unpredictably, thus suffering from both training conflict and catastrophic forgetting issues. The two issues are raised because the gradients from parallel tasks differ in directions and magnitudes. Thus, in this paper, we formulate the PCL into a minimum distance optimization problem among gradients and propose an explicit Asymmetric Gradient Distance (AGD) to evaluate the gradient discrepancy in PCL. AGD considers both gradient magnitude ratios and directions, and has a tolerance when updating with a small gradient of inverse direction, which reduces the imbalanced influence of gradients on parallel task training. Moreover, we present a novel Maximum Discrepancy Optimization (MaxDO) strategy to minimize the maximum discrepancy among multiple gradients. Solving by MaxDO with AGD, parallel training reduces the influence of the training conflict and suppresses the catastrophic forgetting of finished tasks. Extensive experiments validate the effectiveness of our approach on three image recognition datasets in task-incremental and class-incremental PCL. Our code is available at https://github.com/fanlyu/maxdo." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 527, + 128, + 540 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 527, + 128, + 540 + ], + "spans": [ + { + "bbox": [ + 47, + 527, + 128, + 540 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 548, + 288, + 693 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 548, + 288, + 693 + ], + "spans": [ + { + "bbox": [ + 46, + 548, + 288, + 693 + ], + "type": "text", + "content": "Continual Learning (CL) [25, 27, 31, 43], aims to continuously learn new knowledge from a sequence of tasks with non-overlapping data streams over a lifelong time. In the era of Internet of Things, people are using many smart devices, where multi-source data and tasks would be accessed at any time. A CL system should respond to parallel data streams from multiple devices. We study Parallel Continual Learning (PCL), as shown in Fig. 1, where an unfixed number of tasks are trained in a parallel way at any time. Specifically, according to the access time of each task, PCL builds an adaptive number of parallel data pipes, thus enabling instant response to new-coming tasks without pending." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 213, + 547, + 430 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 213, + 547, + 430 + ], + "spans": [ + { + "bbox": [ + 306, + 213, + 547, + 430 + ], + "type": "text", + "content": "Due to the parallel data streams from different tasks, PCL suffers from not only the catastrophic forgetting but the training conflict among parallel tasks. Most existing methods in CL are proposed to tackle the catastrophic forgetting [19, 25], including regularization-based [25, 8, 16, 51, 1], rehearsal-based [31, 9, 21, 4, 41, 36], and architecture-based [33, 49, 39, 38] methods. In PCL, the training processes of different tasks are diverse, i.e., each task starts and ends training unpredictably (see Fig. 1). Thereby the gradient from different task differs in direction and magnitude [50] and may be neutralized. The gradient discrepancies lead to catastrophic forgetting and training conflict issues, which may fail the learning of some tasks. At any time in PCL, therefore, we present that the problem can be formulated to find an optimal gradient in a minimum distance multi-objective optimization, where each objective is to minimize the distance to a target gradient. In general, the distance metric is proportional to the effect of the optimal gradient on the corresponding task." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 434, + 547, + 626 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 434, + 547, + 626 + ], + "spans": [ + { + "bbox": [ + 304, + 434, + 547, + 626 + ], + "type": "text", + "content": "In most situations, the mentioned distance metric " + }, + { + "bbox": [ + 304, + 434, + 547, + 626 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 304, + 434, + 547, + 626 + ], + "type": "text", + "content": " between gradients is set to symmetric intuitively, such as the Euclidean distance and cosine distance. In other words, we usually have " + }, + { + "bbox": [ + 304, + 434, + 547, + 626 + ], + "type": "inline_equation", + "content": "D(\\mathbf{x},\\mathbf{y}) = D(\\mathbf{y},\\mathbf{x})" + }, + { + "bbox": [ + 304, + 434, + 547, + 626 + ], + "type": "text", + "content": " for any " + }, + { + "bbox": [ + 304, + 434, + 547, + 626 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 304, + 434, + 547, + 626 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 434, + 547, + 626 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 304, + 434, + 547, + 626 + ], + "type": "text", + "content": ". However, the gradient influence is imbalanced among parallel tasks in the gradient descent. For example, in Fig. 1, at the marked time, we have three gradients with diverse directions and magnitudes, and updating with any of them provides different influences to the other two. In the minimum distance problem, the optimal solution should have the minimum negative influence on all parallel tasks, but using symmetric metrics means the influences are optimized indistinguishably at the same time. Due to the fact that the gradients are with wide differences, the solution may have large biases, which would get the near-fitting task out of its local minimum but has less impact on a new-coming task." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "type": "text", + "content": "To measure the gradient discrepancy, we hold the opinion that the distance metric in the min-distance problem should be asymmetric. First, though the metric is bound up with both the gradient magnitude and direction, the influences on model training from gradients should be asymmetric, where the model should have more tolerance to small gradients even if they indicate an inverse direction. Second, because" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 493, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 493, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 493, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 702, + 135, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 135, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 135, + 712 + ], + "type": "text", + "content": "*Corresponding author." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "11411" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 71, + 271, + 175 + ], + "blocks": [ + { + "bbox": [ + 50, + 71, + 271, + 175 + ], + "lines": [ + { + "bbox": [ + 50, + 71, + 271, + 175 + ], + "spans": [ + { + "bbox": [ + 50, + 71, + 271, + 175 + ], + "type": "image", + "image_path": "a910f8f9e525de354fa547a0395dbe3623eb2180fd906b4c69b63ea8fa3b0ecd.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 97, + 177, + 216, + 188 + ], + "lines": [ + { + "bbox": [ + 97, + 177, + 216, + 188 + ], + "spans": [ + { + "bbox": [ + 97, + 177, + 216, + 188 + ], + "type": "text", + "content": "Parallel Continual Learning" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 277, + 71, + 369, + 175 + ], + "blocks": [ + { + "bbox": [ + 277, + 71, + 369, + 175 + ], + "lines": [ + { + "bbox": [ + 277, + 71, + 369, + 175 + ], + "spans": [ + { + "bbox": [ + 277, + 71, + 369, + 175 + ], + "type": "image", + "image_path": "3dcbca57a3c25f08a3d55998fdd48e2695f8125929ec84d25d5c7d4d79c63141.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 277, + 177, + 369, + 189 + ], + "lines": [ + { + "bbox": [ + 277, + 177, + 369, + 189 + ], + "spans": [ + { + "bbox": [ + 277, + 177, + 369, + 189 + ], + "type": "text", + "content": "Gradient Discrepancy" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 45, + 192, + 547, + 225 + ], + "lines": [ + { + "bbox": [ + 45, + 192, + 547, + 225 + ], + "spans": [ + { + "bbox": [ + 45, + 192, + 547, + 225 + ], + "type": "text", + "content": "Figure 1. Overview of the proposed method in PCL. Left: PCL trains parallel tasks according to their access time without pending. Middle: At any time, gradients from different tasks (corresponding colors) have unpredicted direction and magnitude (the length of vectors). Right: We formulate PCL into a min-distance problem and propose an asymmetric distance for effective optimization." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 375, + 72, + 544, + 175 + ], + "blocks": [ + { + "bbox": [ + 375, + 72, + 544, + 175 + ], + "lines": [ + { + "bbox": [ + 375, + 72, + 544, + 175 + ], + "spans": [ + { + "bbox": [ + 375, + 72, + 544, + 175 + ], + "type": "image", + "image_path": "583f6a4cdd92d1fbd35fa1ca0c5854137020753c6baf70de6a5ca8d57ec47c1f.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 398, + 177, + 529, + 188 + ], + "lines": [ + { + "bbox": [ + 398, + 177, + 529, + 188 + ], + "spans": [ + { + "bbox": [ + 398, + 177, + 529, + 188 + ], + "type": "text", + "content": "Minimize Asymmetric Distance" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 245, + 287, + 340 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 245, + 287, + 340 + ], + "spans": [ + { + "bbox": [ + 46, + 245, + 287, + 340 + ], + "type": "text", + "content": "gradients are with different magnitudes, the discrepancy between two large gradients is often set to larger than that between small gradients when using symmetric distance, such as Euclidean distance. Directly optimizing using magnitude-aware distance values may lead to the solution close to large gradients and thus hinder the kepping of old tasks. To mitigate the bias from the magnitude difference, it is better to employ the magnitude ratio instead of magnitude itself." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 340, + 288, + 579 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 340, + 288, + 579 + ], + "spans": [ + { + "bbox": [ + 46, + 340, + 288, + 579 + ], + "type": "text", + "content": "Motivated by this, in this paper, we propose an explicit measurement for the learning from gradient discrepancy in PCL, named Asymmetric Gradient Distance (AGD), which considers gradient magnitude ratios and directions, and sets a tolerance for smaller gradients. As shown in Fig. 1, the proposed AGD is used in solving the minimum distance problem with multiple gradients from parallel tasks. Then, we propose an effective optimization strategy for minimizing the gradient discrepancy to avoid self-interference. We name the strategy Maximum Discrepancy Optimization (MaxDO), which minimizes the maximum discrepancy from each gradient to the others. Moreover, to address the catastrophic forgetting issue, we follow the rehearsal strategy [31] in traditional CL and build an extra memory data stream. The rehearsal data stream is used to provide a gradient of finished tasks in MaxDO. Solving by MaxDO with AGD, parallel training mitigates the impacts of the diverse training process and slows the catastrophic forgetting of finished tasks. Extensive results on three datasets show the superiority and effectiveness of our approach." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 59, + 580, + 214, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 580, + 214, + 590 + ], + "spans": [ + { + "bbox": [ + 59, + 580, + 214, + 590 + ], + "type": "text", + "content": "Our main contributions are three-fold:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 594, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 47, + 594, + 287, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 594, + 287, + 641 + ], + "spans": [ + { + "bbox": [ + 47, + 594, + 287, + 641 + ], + "type": "text", + "content": "(1) We formulate the PCL into a minimum distance problem and compare symmetric and asymmetric distances. We show that symmetric metrics are not effective in solving the problem and suggest asymmetric metrics." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 642, + 287, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 642, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 47, + 642, + 287, + 689 + ], + "type": "text", + "content": "(2) We propose an asymmetric metric, named AGD, to evaluate the gradient discrepancy, which is proportional to the gradient magnitude ratios and directions. AGD measures the imbalance of gradient influence in PCL." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 689, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 288, + 713 + ], + "type": "text", + "content": "(3) We propose MaxDO for minimizing gradient discrepancy of different tasks, which maximally reduces the" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 321, + 245, + 547, + 281 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 321, + 245, + 547, + 281 + ], + "spans": [ + { + "bbox": [ + 321, + 245, + 547, + 281 + ], + "type": "text", + "content": "asymmetric discrepancy from a gradient to the others. MaxDO avoids the self-interference among gradients and reduces training conflict and catastrophic forgetting." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 291, + 392, + 303 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 291, + 392, + 303 + ], + "spans": [ + { + "bbox": [ + 306, + 291, + 392, + 303 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 311, + 422, + 323 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 311, + 422, + 323 + ], + "spans": [ + { + "bbox": [ + 306, + 311, + 422, + 323 + ], + "type": "text", + "content": "2.1. Continual Learning" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 329, + 547, + 509 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 329, + 547, + 509 + ], + "spans": [ + { + "bbox": [ + 304, + 329, + 547, + 509 + ], + "type": "text", + "content": "Continual Learning (CL) represents receiving data from new domains continually. In traditional CL, the new domains show up one by one, say serial CL. CL methods can be classified into three kinds. (1) Rehearsal [31, 9, 21, 4, 41, 36, 32], which saves or generates data of old tasks for retraining together with the current training. (2) Regularization [25, 8, 16, 51, 1, 17], which leverages extra regularization terms to consolidate previous knowledge when learning new tasks. (3) Dynamic architecture [33, 49, 39, 38], which freezes task-specific parameters and grows new branches for new tasks automatically. However, most of the existing CL methods are designed for reducing catastrophic forgetting in the serial scenario. Contrastively, in PCL, we need to tackle not only catastrophic forgetting but training conflict among parallel tasks, which is somehow related to multi-task learning." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 515, + 426, + 528 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 515, + 426, + 528 + ], + "spans": [ + { + "bbox": [ + 306, + 515, + 426, + 528 + ], + "type": "text", + "content": "2.2. Multi-Task Learning" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 533, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 547, + 713 + ], + "type": "text", + "content": "Multi-Task Learning (MTL) [7] is used to address multiple tasks with a single model from one to many domains. Traditional MTL solutions can be mainly grouped into feature-based and parameter-based approaches [52]. The feature-based approaches focus on learning common feature representations for multiple tasks [34, 45]. The parameter-based approaches use model parameters in a task to help learn model parameters in other tasks [44, 5, 23]. Recently, some MTL methods propose to find an optimal gradient for updating and can be categorized into three types. (1) Learning-based methods [11], which learn a set of weights by backpropagation. (2) Solving-based methods [40, 29], solve the problem by finding an optimal gradient that is not dominated by the gradient from any task. (3) Calculating-based methods [30, 24, 12, 46, 50, 20, 28] compute the gradient weights" + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "11412" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": "by combining gradients or losses of all tasks. Inspired by MTL, we also formulate the problem into finding an optimal gradient. Specifically, we consider that the optimal gradient should have a small distance to all gradients." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 128, + 162, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 128, + 162, + 140 + ], + "spans": [ + { + "bbox": [ + 47, + 128, + 162, + 140 + ], + "type": "text", + "content": "2.3. Asymmetric Metric" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 147, + 289, + 304 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 147, + 289, + 304 + ], + "spans": [ + { + "bbox": [ + 46, + 147, + 289, + 304 + ], + "type": "text", + "content": "In most situations in neural network, the distance is set to symmetric, e.g., the Euclidean distance. However, the symmetric metric is not always suitable for finding the optimal gradient (see the next section for details). Asymmetric metric [14, 35], also known as quasi-metric [14] or pseudo metric [18, 6], is a generalization of a metric but the symmetry axiom is eliminated in the definition of metric spaces. A classical example of asymmetric metric is the taxicab geometry topology including one-way streets, where a path from point A to B has different streets compared to a path from B to A. In this paper, we propose to measure the gradient discrepancy using an asymmetric metric and raise a novel optimization strategy to minimize the maximum discrepancy." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 314, + 138, + 327 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 314, + 138, + 327 + ], + "spans": [ + { + "bbox": [ + 47, + 314, + 138, + 327 + ], + "type": "text", + "content": "3. Our Approach" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 333, + 203, + 346 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 333, + 203, + 346 + ], + "spans": [ + { + "bbox": [ + 47, + 333, + 203, + 346 + ], + "type": "text", + "content": "3.1. Parallel Continual Learning" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "spans": [ + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "type": "text", + "content": "On a timeline, given a sequence of " + }, + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "type": "text", + "content": " tasks with parallel data streams " + }, + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "type": "inline_equation", + "content": "\\{\\mathcal{D}_1,\\dots ,\\mathcal{D}_T\\}" + }, + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "type": "text", + "content": " for continual training, and each data stream can be accessed and suspended at any time. For simplest, we assume each data stream is i.i.d., and tasks are accessed in order from 1 to " + }, + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "type": "text", + "content": " and there exists no real gap that no data stream flows on the timeline. Note that traditional CL is an edge situation of PCL that all tasks are nose-to-tail. A PCL model contains a shared backbone with parameter " + }, + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "type": "text", + "content": " to learn task-agnostic knowledge and adaptively incremental number of task-specific classifiers with parameters " + }, + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "type": "inline_equation", + "content": "\\theta_{i}" + }, + { + "bbox": [ + 46, + 352, + 289, + 495 + ], + "type": "text", + "content": ". When a new task is accessed, a corresponding task-specific classifier will be constructed." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 496, + 288, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 496, + 288, + 616 + ], + "spans": [ + { + "bbox": [ + 46, + 496, + 288, + 616 + ], + "type": "text", + "content": "In PCL, a task will be forgotten by learning any other tasks when its data stream ends. To avoid forgetting, we leverage the popular rehearsal strategy [31, 9, 21, 4, 41, 36] in our training. Rehearsal builds an extra data stream sampled from all seen tasks and retrans them to suppress the forgetting of finished tasks. For convenience, we denote the rehearsal data stream as " + }, + { + "bbox": [ + 46, + 496, + 288, + 616 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_0" + }, + { + "bbox": [ + 46, + 496, + 288, + 616 + ], + "type": "text", + "content": ". At time " + }, + { + "bbox": [ + 46, + 496, + 288, + 616 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 496, + 288, + 616 + ], + "type": "text", + "content": ", we use " + }, + { + "bbox": [ + 46, + 496, + 288, + 616 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_t" + }, + { + "bbox": [ + 46, + 496, + 288, + 616 + ], + "type": "text", + "content": " to represent the activated data streams (including " + }, + { + "bbox": [ + 46, + 496, + 288, + 616 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_0" + }, + { + "bbox": [ + 46, + 496, + 288, + 616 + ], + "type": "text", + "content": "). Together with the rehearsal data stream, PCL training yields the following dynamic multi-objective empirical risk minimization:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 102, + 625, + 287, + 645 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 102, + 625, + 287, + 645 + ], + "spans": [ + { + "bbox": [ + 102, + 625, + 287, + 645 + ], + "type": "interline_equation", + "content": "\\min _ {\\boldsymbol {\\theta}, \\left\\{\\boldsymbol {\\theta} _ {i} \\mid i \\in \\mathcal {T} _ {t} \\right\\}} \\quad \\left\\{\\ell_ {i} \\left(\\mathcal {D} _ {i}\\right) \\mid i \\in \\mathcal {T} _ {t} \\right\\}. \\tag {1}", + "image_path": "826b7e0eea835d29b0fd99c524495510a1e45e5c39ffd6ad1d488c65014f00e6.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 654, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 654, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 654, + 289, + 715 + ], + "type": "text", + "content": "Because the task-specific classifiers are updated by their own gradients " + }, + { + "bbox": [ + 46, + 654, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\theta_{i}\\gets \\theta_{i} - \\alpha_{i}\\nabla_{\\theta_{i}}\\ell_{i}" + }, + { + "bbox": [ + 46, + 654, + 289, + 715 + ], + "type": "inline_equation", + "content": "(\\forall i\\in T_{t})" + }, + { + "bbox": [ + 46, + 654, + 289, + 715 + ], + "type": "text", + "content": " with step size " + }, + { + "bbox": [ + 46, + 654, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\alpha_{i}" + }, + { + "bbox": [ + 46, + 654, + 289, + 715 + ], + "type": "text", + "content": ", we focus on the update of the shared backbone " + }, + { + "bbox": [ + 46, + 654, + 289, + 715 + ], + "type": "inline_equation", + "content": "\\pmb{\\theta}" + }, + { + "bbox": [ + 46, + 654, + 289, + 715 + ], + "type": "text", + "content": ". At any PCL step, the goal of dynamic MOO is to optimize multiple objectives simultaneously while updating only once, and" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": "the only update of the shared parameters depends on the gradients of all in-training tasks. It will exit an uncertain number of tasks, and each task will provide a task-specific gradient on the shared parameter " + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": ". Let " + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_i = \\nabla_\\theta \\ell_i" + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": " be a step size for optimization. The problem of the backbone update can be formulated as follows:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 322, + 149, + 545, + 163 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 322, + 149, + 545, + 163 + ], + "spans": [ + { + "bbox": [ + 322, + 149, + 545, + 163 + ], + "type": "interline_equation", + "content": "\\boldsymbol {\\theta} \\leftarrow \\boldsymbol {\\theta} - \\alpha \\mathbf {d} ^ {*}, \\quad \\text {w h e r e} \\mathbf {d} ^ {*} = f \\left(\\left\\{\\mathbf {g} _ {i} | \\forall i \\in \\mathcal {T} _ {t} \\right\\}\\right). \\tag {2}", + "image_path": "257eab1504c94421dcac4f82ae72d096f33a149a4c7edc69f00f4c58d8b4fe3b.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 168, + 547, + 216 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 168, + 547, + 216 + ], + "spans": [ + { + "bbox": [ + 304, + 168, + 547, + 216 + ], + "type": "text", + "content": "The key question is how to compute the optimal gradient " + }, + { + "bbox": [ + 304, + 168, + 547, + 216 + ], + "type": "inline_equation", + "content": "\\mathbf{d}^*" + }, + { + "bbox": [ + 304, + 168, + 547, + 216 + ], + "type": "text", + "content": " via the function " + }, + { + "bbox": [ + 304, + 168, + 547, + 216 + ], + "type": "inline_equation", + "content": "f(\\cdot)" + }, + { + "bbox": [ + 304, + 168, + 547, + 216 + ], + "type": "text", + "content": ". In this paper, we define the function " + }, + { + "bbox": [ + 304, + 168, + 547, + 216 + ], + "type": "inline_equation", + "content": "f(\\cdot)" + }, + { + "bbox": [ + 304, + 168, + 547, + 216 + ], + "type": "text", + "content": " as a min-distance multi-objective problem by minimizing the gradient distance from all in-training tasks:" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 347, + 221, + 545, + 239 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 347, + 221, + 545, + 239 + ], + "spans": [ + { + "bbox": [ + 347, + 221, + 545, + 239 + ], + "type": "interline_equation", + "content": "\\mathbf {d} ^ {*} = \\arg \\min _ {\\mathbf {d}} \\quad \\left\\{D \\left(\\mathbf {d}, \\mathbf {g} _ {i}\\right) \\mid \\forall i \\in \\mathcal {T} \\right\\}, \\tag {3}", + "image_path": "9e6eff4cd6cc9beca37cefe2f4cdc5cd53b010ba6c18a8a60387f53d78a93505.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 243, + 545, + 303 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 243, + 545, + 303 + ], + "spans": [ + { + "bbox": [ + 304, + 243, + 545, + 303 + ], + "type": "text", + "content": "where we need to identify what distance metric " + }, + { + "bbox": [ + 304, + 243, + 545, + 303 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 304, + 243, + 545, + 303 + ], + "type": "text", + "content": " is used to measure gradient discrepancy. The motivation of Eq. (3) is that for the task " + }, + { + "bbox": [ + 304, + 243, + 545, + 303 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 243, + 545, + 303 + ], + "type": "text", + "content": " in PCL, its own gradient " + }, + { + "bbox": [ + 304, + 243, + 545, + 303 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_i" + }, + { + "bbox": [ + 304, + 243, + 545, + 303 + ], + "type": "text", + "content": " is the most qualified update direction for itself. The solution " + }, + { + "bbox": [ + 304, + 243, + 545, + 303 + ], + "type": "inline_equation", + "content": "\\mathbf{d}^*" + }, + { + "bbox": [ + 304, + 243, + 545, + 303 + ], + "type": "text", + "content": " should be as close to every gradient as possible." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 303, + 547, + 363 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 303, + 547, + 363 + ], + "spans": [ + { + "bbox": [ + 304, + 303, + 547, + 363 + ], + "type": "text", + "content": "A related but different task is Federated Continual Learning (FCL) [48, 42]. Most FCL methods primarily focus on serial training, involving multiple clients in training a shared task at the same time. It is meaningful to study Federated PCL in the future for the advancement of privacy protection." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 369, + 545, + 382 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 369, + 545, + 382 + ], + "spans": [ + { + "bbox": [ + 305, + 369, + 545, + 382 + ], + "type": "text", + "content": "3.2. Measuring Asymmetric Gradient Discrepancy" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "spans": [ + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": "To measure gradient discrepancy, the Euclidean Distance (EuDist, " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "D(\\mathbf{x},\\mathbf{y}) = \\| \\mathbf{x} - \\mathbf{y}\\| \\in [0,\\infty)" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": ") and Cosine Distance (CosDist, " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "D(\\mathbf{x},\\mathbf{y}) = 1 - \\frac{\\mathbf{x}^\\top\\mathbf{y}}{\\|\\mathbf{x}\\|\\|\\mathbf{y}\\|} \\in [0,2]" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": ") are the two most popular choices. Both of them are symmetric, i.e., " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "D(\\mathbf{x},\\mathbf{y}) = D(\\mathbf{y},\\mathbf{x})" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": ". A symmetric metric " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "D(\\mathbf{x},\\mathbf{y})" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": " means the forward influence (" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": ") and backward influence (" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": ") are equal. For example, given two in-training tasks A and B, the distance " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "D(\\mathbf{g}_{\\mathrm{A}},\\mathbf{g}_{\\mathrm{B}})" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": " represents both the effect of " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{A}}" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": " on task B and " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{B}}" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": " on task A because of " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "D(\\mathbf{g}_{\\mathrm{A}},\\mathbf{g}_{\\mathrm{B}}) = D(\\mathbf{g}_{\\mathrm{B}},\\mathbf{g}_{\\mathrm{A}})" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": ". Note that large distance from " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{A}}" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{B}}" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": " means large negative influence on the training of task B with " + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{A}}" + }, + { + "bbox": [ + 304, + 387, + 547, + 521 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "spans": [ + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "text", + "content": "However, the model update is highly related to gradient magnitude and direction, which are asymmetric to model updating. The influence of the gradient " + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{A}}" + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "text", + "content": " on task B may be quite different from that of the gradient " + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{B}}" + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "text", + "content": " on task A. In previous studies [31, 9, 50], the two tasks are treated as conflict when " + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "inline_equation", + "content": "\\langle \\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}} \\rangle < 0" + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "text", + "content": ". In PCL, due to the diverse training process, gradients from parallel tasks are diverse in magnitude and direction. When " + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "inline_equation", + "content": "\\| \\mathbf{g}_{\\mathrm{A}} \\| \\ll \\| \\mathbf{g}_{\\mathrm{B}} \\|" + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "text", + "content": ", the gradient " + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{A}}" + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "text", + "content": " will have little negative influence on task B even if " + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "inline_equation", + "content": "\\langle \\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}} \\rangle < 0" + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "text", + "content": "; when " + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "inline_equation", + "content": "\\| \\mathbf{g}_{\\mathrm{A}} \\| \\gg \\| \\mathbf{g}_{\\mathrm{B}} \\|" + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "text", + "content": " (e.g., a new task A is accessed when task B has been trained for some time near convergence), the update produces huge impact on task B even if " + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "inline_equation", + "content": "\\langle \\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}} \\rangle > 0" + }, + { + "bbox": [ + 304, + 522, + 547, + 689 + ], + "type": "text", + "content": ". Using traditional symmetric distances can hardly represent the asymmetric update influence difference." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "content": "To effectively measure gradient discrepancy in PCL, we introduce the asymmetric metric." + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "11413" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 55, + 70, + 208, + 199 + ], + "blocks": [ + { + "bbox": [ + 55, + 70, + 208, + 199 + ], + "lines": [ + { + "bbox": [ + 55, + 70, + 208, + 199 + ], + "spans": [ + { + "bbox": [ + 55, + 70, + 208, + 199 + ], + "type": "image", + "image_path": "d817f0f7b570a583e20f971b61ee404f8f1aefd9e24ae6a902284e7b51e1bbbe.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 102, + 205, + 164, + 220 + ], + "lines": [ + { + "bbox": [ + 102, + 205, + 164, + 220 + ], + "spans": [ + { + "bbox": [ + 102, + 205, + 164, + 220 + ], + "type": "text", + "content": "(a) " + }, + { + "bbox": [ + 102, + 205, + 164, + 220 + ], + "type": "inline_equation", + "content": "z = 1 - \\frac{\\mathbf{x}^{\\mathrm{T}}\\mathbf{y}}{||\\mathbf{x}||||\\mathbf{y}||}" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 219, + 70, + 373, + 200 + ], + "blocks": [ + { + "bbox": [ + 219, + 70, + 373, + 200 + ], + "lines": [ + { + "bbox": [ + 219, + 70, + 373, + 200 + ], + "spans": [ + { + "bbox": [ + 219, + 70, + 373, + 200 + ], + "type": "image", + "image_path": "b6afae9c4b7b9f2ba22ae0b15e703ef6ba7047b34c5ed44aa2745f734392ce7e.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 251, + 205, + 343, + 217 + ], + "lines": [ + { + "bbox": [ + 251, + 205, + 343, + 217 + ], + "spans": [ + { + "bbox": [ + 251, + 205, + 343, + 217 + ], + "type": "text", + "content": "(b) " + }, + { + "bbox": [ + 251, + 205, + 343, + 217 + ], + "type": "inline_equation", + "content": "z = \\| \\mathbf{x} - \\mathbf{y}\\|" + }, + { + "bbox": [ + 251, + 205, + 343, + 217 + ], + "type": "text", + "content": " , " + }, + { + "bbox": [ + 251, + 205, + 343, + 217 + ], + "type": "inline_equation", + "content": "\\| \\mathbf{y}\\| = 0.2" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "lines": [ + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "spans": [ + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "text", + "content": "Figure 2. The measures of two gradient discrepancy from " + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "text", + "content": ". Note that the " + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "text", + "content": "- and " + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "inline_equation", + "content": "y" + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "text", + "content": "-axes are the angle (i.e., " + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "inline_equation", + "content": "\\angle \\mathbf{x}, \\mathbf{y}" + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "text", + "content": ") between " + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "text", + "content": ", and the magnitude ratio " + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "inline_equation", + "content": "\\frac{\\|\\mathbf{x}\\|}{\\|\\mathbf{y}\\|}" + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "text", + "content": ", respectively. (a) Cosine distance; (b) Euclidean distance where " + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "inline_equation", + "content": "\\|\\mathbf{y}\\| = 0.2" + }, + { + "bbox": [ + 46, + 220, + 547, + 253 + ], + "type": "text", + "content": " as an example; (c) Asymmetric gradient distance. Please see Appendix for the contours." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 383, + 71, + 533, + 200 + ], + "blocks": [ + { + "bbox": [ + 383, + 71, + 533, + 200 + ], + "lines": [ + { + "bbox": [ + 383, + 71, + 533, + 200 + ], + "spans": [ + { + "bbox": [ + 383, + 71, + 533, + 200 + ], + "type": "image", + "image_path": "345811336273ba2622e3644d54005241be6d9bbb510a1dd1f32611206276f100.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 430, + 205, + 493, + 220 + ], + "lines": [ + { + "bbox": [ + 430, + 205, + 493, + 220 + ], + "spans": [ + { + "bbox": [ + 430, + 205, + 493, + 220 + ], + "type": "text", + "content": "(c) " + }, + { + "bbox": [ + 430, + 205, + 493, + 220 + ], + "type": "inline_equation", + "content": "z = \\frac{\\|\\mathbf{x} - \\mathbf{y}\\|}{\\|\\mathbf{y}\\| + \\|\\mathbf{x} - \\mathbf{y}\\|}" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 273, + 287, + 297 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 273, + 287, + 297 + ], + "spans": [ + { + "bbox": [ + 46, + 273, + 287, + 297 + ], + "type": "text", + "content": "Lemma 1 (Asymmetric Metric [14]) " + }, + { + "bbox": [ + 46, + 273, + 287, + 297 + ], + "type": "inline_equation", + "content": "D:\\mathcal{X}\\times \\mathcal{X}\\to \\mathbb{R}" + }, + { + "bbox": [ + 46, + 273, + 287, + 297 + ], + "type": "text", + "content": " is an asymmetric metric (a.k.a. quasi-metric [47]) if " + }, + { + "bbox": [ + 46, + 273, + 287, + 297 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 46, + 273, + 287, + 297 + ], + "type": "text", + "content": " satisfies" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 299, + 251, + 324 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 47, + 299, + 233, + 312 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 299, + 233, + 312 + ], + "spans": [ + { + "bbox": [ + 47, + 299, + 233, + 312 + ], + "type": "text", + "content": "(1) " + }, + { + "bbox": [ + 47, + 299, + 233, + 312 + ], + "type": "inline_equation", + "content": "D(\\mathbf{x},\\mathbf{y})\\geq 0" + }, + { + "bbox": [ + 47, + 299, + 233, + 312 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 299, + 233, + 312 + ], + "type": "inline_equation", + "content": "\\forall \\mathbf{x}\\in \\mathbb{R}^d,D(\\mathbf{x},\\mathbf{x}) = 0;" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 312, + 251, + 324 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 312, + 251, + 324 + ], + "spans": [ + { + "bbox": [ + 48, + 312, + 251, + 324 + ], + "type": "text", + "content": "(2) " + }, + { + "bbox": [ + 48, + 312, + 251, + 324 + ], + "type": "inline_equation", + "content": "D(\\mathbf{x},\\mathbf{z})\\leq D(\\mathbf{x},\\mathbf{y}) + D(\\mathbf{y},\\mathbf{z}),\\forall \\mathbf{x},\\mathbf{y},\\mathbf{z}\\in \\mathbb{R}^{d}." + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 46, + 330, + 288, + 378 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 330, + 288, + 378 + ], + "spans": [ + { + "bbox": [ + 46, + 330, + 288, + 378 + ], + "type": "text", + "content": "The asymmetric metric does not require the symmetric property, i.e., " + }, + { + "bbox": [ + 46, + 330, + 288, + 378 + ], + "type": "inline_equation", + "content": "D(\\mathbf{x}, \\mathbf{y}) = D(\\mathbf{y}, \\mathbf{x})" + }, + { + "bbox": [ + 46, + 330, + 288, + 378 + ], + "type": "text", + "content": ". Based on the definition, in this paper, we design an asymmetric metric to measure gradient discrepancy named Asymmetric Gradient Distance." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 388, + 272, + 399 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 388, + 272, + 399 + ], + "spans": [ + { + "bbox": [ + 46, + 388, + 272, + 399 + ], + "type": "text", + "content": "Definition 1 (Asymmetric Gradient Distance (AGD))" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 400, + 287, + 424 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 400, + 287, + 424 + ], + "spans": [ + { + "bbox": [ + 46, + 400, + 287, + 424 + ], + "type": "text", + "content": "Given two gradient " + }, + { + "bbox": [ + 46, + 400, + 287, + 424 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_A" + }, + { + "bbox": [ + 46, + 400, + 287, + 424 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 400, + 287, + 424 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_B" + }, + { + "bbox": [ + 46, + 400, + 287, + 424 + ], + "type": "text", + "content": ", the asymmetric gradient distance is defined as" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 55, + 433, + 278, + 475 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 433, + 278, + 475 + ], + "spans": [ + { + "bbox": [ + 55, + 433, + 278, + 475 + ], + "type": "interline_equation", + "content": "\\widehat {D} (\\mathbf {g} _ {A}, \\mathbf {g} _ {B}) = \\left\\{ \\begin{array}{c l} 0 & , \\quad i f \\mathbf {g} _ {A} = \\mathbf {g} _ {B} = \\mathbf {0}, \\\\ \\frac {\\| \\mathbf {g} _ {A} - \\mathbf {g} _ {B} \\|}{\\| \\mathbf {g} _ {B} \\| + \\| \\mathbf {g} _ {A} - \\mathbf {g} _ {B} \\|}, & O t h e r w i s e. \\end{array} \\right.", + "image_path": "2039a243702e7d37388a922cf4e91781e672ea34a5012642de3dde3a50244311.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 46, + 487, + 287, + 571 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 487, + 287, + 571 + ], + "spans": [ + { + "bbox": [ + 46, + 487, + 287, + 571 + ], + "type": "text", + "content": "In Definition 1, we consider the edge situation when " + }, + { + "bbox": [ + 46, + 487, + 287, + 571 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{A}} = \\mathbf{g}_{\\mathrm{B}} = \\mathbf{0}" + }, + { + "bbox": [ + 46, + 487, + 287, + 571 + ], + "type": "text", + "content": " to meet the definition of the asymmetric metric in Lemma 1. In AGD, gradient directions and magnitudes are considered. Instead of using gradient magnitude value difference, we use magnitude ratio difference to avoid the diverse training of different tasks in PCL. Therefore, we derive the corollary of the magnitude ratio:" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 47, + 578, + 286, + 592 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 578, + 286, + 592 + ], + "spans": [ + { + "bbox": [ + 47, + 578, + 286, + 592 + ], + "type": "text", + "content": "Corollary 1 " + }, + { + "bbox": [ + 47, + 578, + 286, + 592 + ], + "type": "inline_equation", + "content": "\\widehat{D} (\\mathbf{g}_A,\\mathbf{g}_B)" + }, + { + "bbox": [ + 47, + 578, + 286, + 592 + ], + "type": "text", + "content": " is an asymmetric metric and holds" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 64, + 601, + 271, + 630 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 64, + 601, + 271, + 630 + ], + "spans": [ + { + "bbox": [ + 64, + 601, + 271, + 630 + ], + "type": "interline_equation", + "content": "\\lim_{\\substack{\\| \\mathbf{g}_{A}\\| \\\\ \\| \\mathbf{g}_{B}\\| \\to \\infty}}\\widehat{D} (\\mathbf{g}_{A},\\mathbf{g}_{B}) = 1,\\quad \\lim_{\\substack{\\| \\mathbf{g}_{A}\\| \\\\ \\| \\mathbf{g}_{B}\\| \\to 0}}\\widehat{D} (\\mathbf{g}_{A},\\mathbf{g}_{B}) = \\frac{1}{2}.", + "image_path": "7ac545e36fae551b06d7241d1dbb0f04b1a20ccac9eb04872939a265a71b5ddd.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "type": "text", + "content": "We illustrate why AGD is qualified to evaluate the gradient discrepancy according to the definition and corollary. In Definition 1, we use AGD to represent the influence of " + }, + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{A}}" + }, + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "type": "text", + "content": " on task B rather than the inverse. This is the key difference from the symmetric metrics such as Euclidean distance. Specifically, " + }, + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{A}}" + }, + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "type": "text", + "content": " may make task B worse if " + }, + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\widehat{D}(\\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}})" + }, + { + "bbox": [ + 46, + 641, + 288, + 714 + ], + "type": "text", + "content": " is large (close" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "spans": [ + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "text", + "content": "to 1). If " + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "inline_equation", + "content": "\\widehat{D}(\\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}})" + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "text", + "content": " is close to 0, " + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{A}}" + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{B}}" + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "text", + "content": " has less conflict. Moreover, Corollary 1 involves that when " + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "inline_equation", + "content": "\\|\\mathbf{g}_{\\mathrm{A}}\\| \\ll \\|\\mathbf{g}_{\\mathrm{B}}\\|" + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "text", + "content": ", AGD has a tolerance " + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "inline_equation", + "content": "\\frac{1}{2}" + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "text", + "content": " even if " + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "inline_equation", + "content": "\\langle \\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}} \\rangle < 0" + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "text", + "content": ", which means the impact of " + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{A}}" + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "text", + "content": " on task B is mild. This is because updating with a zero gradient will neither improve nor damage the performance. Even though, we prefer positive influence rather than non-influence. Thus, we define that the distance " + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "inline_equation", + "content": "\\widehat{D}(\\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}})" + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "text", + "content": " in this situation is the mid-level " + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "inline_equation", + "content": "(\\frac{1}{2})" + }, + { + "bbox": [ + 304, + 272, + 547, + 380 + ], + "type": "text", + "content": " in the value range([0,1]). See different tolerances in our experiments." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 380, + 547, + 489 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 380, + 547, + 489 + ], + "spans": [ + { + "bbox": [ + 304, + 380, + 547, + 489 + ], + "type": "text", + "content": "Moreover, we compare AGD (Fig. 2(c)) with Euclidean and cosine distance in Fig. 2. First, the cosine distance (Fig. 2(a)) is magnitude irrelevant, which ignores the magnitude difference in PCL. Second, the Euclidean distance (Fig. 2(b)) depends heavily on the magnitude value difference, but ignores that the gradient influence on the model update is asymmetric. For example, when " + }, + { + "bbox": [ + 304, + 380, + 547, + 489 + ], + "type": "inline_equation", + "content": "\\| \\mathbf{x}\\| \\to 0" + }, + { + "bbox": [ + 304, + 380, + 547, + 489 + ], + "type": "text", + "content": ", EuDist will get large if we have large " + }, + { + "bbox": [ + 304, + 380, + 547, + 489 + ], + "type": "inline_equation", + "content": "\\| \\mathbf{y}\\|" + }, + { + "bbox": [ + 304, + 380, + 547, + 489 + ], + "type": "text", + "content": " without any tolerance, which ignores the non-influence of zero gradient." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 306, + 495, + 503, + 509 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 495, + 503, + 509 + ], + "spans": [ + { + "bbox": [ + 306, + 495, + 503, + 509 + ], + "type": "text", + "content": "3.3. Maximum Discrepancy Optimization" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "spans": [ + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "text", + "content": "At time " + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "text", + "content": ", let the optimal solution to Problem (3) be " + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "inline_equation", + "content": "\\mathbf{d}^*" + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_t" + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "text", + "content": " is the index set of in-training tasks (" + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "inline_equation", + "content": "\\mathcal{T}" + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "text", + "content": " for simplicity). However, directly optimizing the problem is difficult due to the large decision space that has the same dimension as " + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "inline_equation", + "content": "\\pmb{\\theta}" + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "text", + "content": ". Following [28, 40], we use linear scalarization to solve the transformed problem that allows only optimizing decision variable " + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "inline_equation", + "content": "\\mathbf{w} \\in \\mathbb{R}^{|\\mathcal{T}|}" + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "text", + "content": ". That is, let " + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "inline_equation", + "content": "\\mathbf{d} = \\sum_{i \\in \\mathcal{T}} \\mathbf{w}_i \\mathbf{g}_i" + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "inline_equation", + "content": "\\forall \\mathbf{w}_i \\geq 0" + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "inline_equation", + "content": "\\sum_{i \\in \\mathcal{T}} \\mathbf{w}_i = 1" + }, + { + "bbox": [ + 304, + 514, + 547, + 611 + ], + "type": "text", + "content": ", we have" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 315, + 619, + 545, + 658 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 619, + 545, + 658 + ], + "spans": [ + { + "bbox": [ + 315, + 619, + 545, + 658 + ], + "type": "interline_equation", + "content": "\\mathbf {w} ^ {*} = \\underset {\\mathbf {w}} {\\arg \\min } \\quad \\left\\{\\widehat {D} \\left(\\sum_ {j} \\mathbf {w} _ {j} \\mathbf {g} _ {j}, \\mathbf {g} _ {i}\\right) | \\forall i \\in \\mathcal {T} \\right\\}. \\tag {4}", + "image_path": "1c231b228e4b9fe01e6461cbf6baa33104f53c683517f18dcb75cdd5501b9827.jpg" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "type": "text", + "content": "Each objective of the dual problem will be highly affected by the minimum discrepancy, i.e., each gradient itself. For example, by minimizing objective " + }, + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\widehat{D} (\\sum_{j}\\mathbf{w}_{j}\\mathbf{g}_{j},\\mathbf{g}_{i})" + }, + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "type": "text", + "content": " , weight " + }, + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{w}_i" + }, + { + "bbox": [ + 304, + 665, + 547, + 714 + ], + "type": "text", + "content": " is more like to be activated than others. Thus, multiple" + } + ] + } + ], + "index": 24 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "11414" + } + ] + } + ], + "index": 25 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 48, + 69, + 547, + 224 + ], + "blocks": [ + { + "bbox": [ + 48, + 69, + 547, + 224 + ], + "lines": [ + { + "bbox": [ + 48, + 69, + 547, + 224 + ], + "spans": [ + { + "bbox": [ + 48, + 69, + 547, + 224 + ], + "type": "image", + "image_path": "86a186d1cdc01e2ac887d2d6f6b1e43f3672b64a687f052eca119106534c96f2.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "lines": [ + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "spans": [ + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "type": "text", + "content": "Figure 3. Schematic of Maximum Discrepancy Optimization. Given multiple gradients " + }, + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{g}_i|\\forall i\\in \\mathcal{T}\\}" + }, + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "type": "inline_equation", + "content": "(|\\mathcal{T}| = 4" + }, + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "type": "text", + "content": " for example) (1) A weight matrix " + }, + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "type": "inline_equation", + "content": "\\mathbf{W}" + }, + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "type": "text", + "content": " is initialized with " + }, + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "type": "inline_equation", + "content": "\\frac{1}{|\\mathcal{T}|}" + }, + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "type": "text", + "content": " for each entry. (2) For each row, the off-diagonal entries are used to weighted gradients and optimized for minimum AGD to the target gradient. (3) The diagonal entries " + }, + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "type": "inline_equation", + "content": "(\\square)" + }, + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "type": "text", + "content": " are used to optimize with min-norm with MGDA. (4) The final weight matrix is reduced by each column for the final weights " + }, + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "type": "inline_equation", + "content": "(w^{\\prime})" + }, + { + "bbox": [ + 46, + 228, + 547, + 275 + ], + "type": "text", + "content": ". See Sec. 3.3 for details." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "code", + "bbox": [ + 50, + 308, + 267, + 470 + ], + "blocks": [ + { + "bbox": [ + 53, + 295, + 195, + 307 + ], + "lines": [ + { + "bbox": [ + 53, + 295, + 195, + 307 + ], + "spans": [ + { + "bbox": [ + 53, + 295, + 195, + 307 + ], + "type": "text", + "content": "Algorithm 1: MaxDO ( ) in PCL" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "code_caption" + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "lines": [ + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "spans": [ + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "text", + "content": "Input: Parameters " + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "inline_equation", + "content": "\\theta ,\\theta_{1:T}" + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "text", + "content": " ; Step sizes " + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "inline_equation", + "content": "\\alpha_{1:T}" + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "text", + "content": " Output: " + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "inline_equation", + "content": "\\theta ,\\theta_{1:T}" + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "text", + "content": " \n1 for t in timeline do \n2 " + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "inline_equation", + "content": "\\mathcal{T}_t\\gets" + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "text", + "content": " in-training task index; \n3 for " + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "inline_equation", + "content": "i\\in \\mathcal{T}_t" + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "text", + "content": " do \n4 " + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "inline_equation", + "content": "\\begin{array}{r}\\mathcal{B}_i\\sim \\mathcal{D}_i;\\\\ \\pmb {\\theta}_i\\gets \\pmb {\\theta}_i - \\alpha_i\\nabla_{\\pmb{\\theta}_i}\\ell_i(\\mathcal{B}_i);\\\\ \\mathbf{g}_i = \\nabla_\\theta \\ell_i(\\mathcal{B}_i); \\end{array}" + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "text", + "content": " \n5 \n6 end \n7 W\\* Optimization by Eq. (5); d\\* Final graident from Eq. (6); \n8 \n9 " + }, + { + "bbox": [ + 50, + 308, + 267, + 470 + ], + "type": "inline_equation", + "content": "\\theta \\leftarrow \\theta -\\alpha \\mathbf{d}^{*};" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "code_body" + } + ], + "index": 3, + "sub_type": "algorithm" + }, + { + "bbox": [ + 46, + 500, + 287, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 500, + 287, + 536 + ], + "spans": [ + { + "bbox": [ + 46, + 500, + 287, + 536 + ], + "type": "text", + "content": "objectives will be compromised by multiple self-interference but fail to reduce the maximum discrepancy in the dual problem optimization." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": "As shown in Fig. 3, we propose Maximum Discrepancy Optimization (MaxDO) to reduce the maximum gradient discrepancy. Specifically, instead of the weight vector " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{w} \\in \\mathbb{R}^{|\\mathcal{T}|}" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": ", we optimize a weight matrix " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{W} \\in \\mathbb{R}^{|\\mathcal{T}| \\times |\\mathcal{T}|}" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": " in which " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "\\forall \\mathbf{W}_{ij} \\geq 0" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{W}" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": " can be combined by a diagonal vector " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "\\dot{\\mathbf{w}} = [\\mathbf{W}_{1,1}, \\dots, \\mathbf{W}_{|\\mathcal{T}|,|\\mathcal{T}|}]" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": " and an off-diagonal matrix " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "\\widetilde{\\mathbf{W}} = \\mathbf{W} - \\mathrm{Diag}(\\dot{\\mathbf{w}})" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "\\sum_{i \\in \\mathcal{T}} \\dot{\\mathbf{w}}_i = 1" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "\\sum_{j \\in \\mathcal{T}} \\widetilde{\\mathbf{W}}_{ij} = 1, \\forall i" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": ". Thus, " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "\\sum_{i,j \\in \\mathcal{T}} \\mathbf{W}_{ij} = |\\mathcal{T}| + 1" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": " and the two weights are independent and can be optimized without disturbance as follows: (1) " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "\\widetilde{\\mathbf{W}}" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": ", computed by Stochastic Gradient Descent (SGD), is used to make up the maximum gradient discrepancy. The objectives of any two rows in " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "\\widetilde{\\mathbf{W}}" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": " are different. For row " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": ", to formulate the maximum discrepancy of gradient " + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_i" + }, + { + "bbox": [ + 46, + 538, + 289, + 714 + ], + "type": "text", + "content": ", the objective is the combina" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 292, + 548, + 473 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 292, + 548, + 473 + ], + "spans": [ + { + "bbox": [ + 304, + 292, + 548, + 473 + ], + "type": "text", + "content": "tion of non-diagonal entries. The weighted other gradients should be with the smallest asymmetric distance to " + }, + { + "bbox": [ + 304, + 292, + 548, + 473 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_i" + }, + { + "bbox": [ + 304, + 292, + 548, + 473 + ], + "type": "text", + "content": ". (2) " + }, + { + "bbox": [ + 304, + 292, + 548, + 473 + ], + "type": "inline_equation", + "content": "\\dot{\\mathbf{w}}" + }, + { + "bbox": [ + 304, + 292, + 548, + 473 + ], + "type": "text", + "content": " is obtained by the Multiple Gradient Descent Algorithm (MGDA) [15], which is to obtain a weighted gradient that does not damage any tasks with a min-norm optimization. The objective of MGDA is 0 and the resulting point satisfies the Karush-Kuhn-Tucker condition or the solution gives a Pareto descent direction that improves all tasks. See Appendix for more details of MGDA. For each off-diagonal entry of the " + }, + { + "bbox": [ + 304, + 292, + 548, + 473 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 292, + 548, + 473 + ], + "type": "text", + "content": "-th column, their sum means the effect of the gradient " + }, + { + "bbox": [ + 304, + 292, + 548, + 473 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_i" + }, + { + "bbox": [ + 304, + 292, + 548, + 473 + ], + "type": "text", + "content": " reducing the maximum discrepancy from other gradients. MGDA is used to reduce the possible negative effect in MaxDO. On the other hand, MaxDO reduces the training failure of new tasks in MGDA. To sum up, our MaxDO with AGD can be computed by" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 337, + 477, + 547, + 587 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 337, + 477, + 547, + 587 + ], + "spans": [ + { + "bbox": [ + 337, + 477, + 547, + 587 + ], + "type": "interline_equation", + "content": "\\mathbf {W} ^ {*} = \\underbrace {\\arg \\min _ {\\widetilde {\\mathbf {W}}} \\sum_ {\\forall i \\in \\mathcal {T}} \\widehat {D} \\left(\\sum_ {j \\neq i} \\widetilde {\\mathbf {W}} _ {i , j} \\mathbf {g} _ {j} , \\mathbf {g} _ {i}\\right)} _ {\\text {S G D w i t h M a x i m u m D i s c r e p a n c y}} + \\operatorname {D i a g} \\underbrace {\\left(\\underset {\\dot {\\mathbf {w}}} {\\arg \\min } \\left\\| \\sum_ {j} \\dot {\\mathbf {w}} _ {j} \\mathbf {g} _ {j} \\right\\|\\right)} _ {\\text {M G D A [ 1 5 ]}}. \\tag {5}", + "image_path": "cccf5f4abb7af8c63206a3b69d751fad773d274669c0411e11625847bf08de41.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 592, + 548, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 592, + 548, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 592, + 548, + 715 + ], + "type": "text", + "content": "In Eq. (5), we can obtain an approximate solution by combining the closed-form solution and the iterative solution. Fig. 3 reveals the diagram of solving MaxDO. We project the solution of SGD onto the feasible set " + }, + { + "bbox": [ + 304, + 592, + 548, + 715 + ], + "type": "inline_equation", + "content": "(\\sum_{i \\neq j} \\mathbf{W}_{ij} = 1)" + }, + { + "bbox": [ + 304, + 592, + 548, + 715 + ], + "type": "text", + "content": " via softmax at each step in the multiple steps for fast convergence. First, we initialize all entries of " + }, + { + "bbox": [ + 304, + 592, + 548, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{W}" + }, + { + "bbox": [ + 304, + 592, + 548, + 715 + ], + "type": "text", + "content": " by " + }, + { + "bbox": [ + 304, + 592, + 548, + 715 + ], + "type": "inline_equation", + "content": "\\frac{1}{|\\mathcal{T}|}" + }, + { + "bbox": [ + 304, + 592, + 548, + 715 + ], + "type": "text", + "content": ". Then, the off-diagonal matrix is used to minimize the maximum gradient discrepancy via SGD and the diagonal vector is optimized by min-norm. Finally, the final weights are reduced to a vector by dividing " + }, + { + "bbox": [ + 304, + 592, + 548, + 715 + ], + "type": "inline_equation", + "content": "|\\mathcal{T}| + 1" + }, + { + "bbox": [ + 304, + 592, + 548, + 715 + ], + "type": "text", + "content": " to guarantee that their sum" + } + ] + } + ], + "index": 8 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "11415" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 288, + 122 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 288, + 122 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 288, + 122 + ], + "type": "text", + "content": "is 1. Note that, MaxDO is implemented only when " + }, + { + "bbox": [ + 46, + 72, + 288, + 122 + ], + "type": "inline_equation", + "content": "|\\mathcal{T}| > 1" + }, + { + "bbox": [ + 46, + 72, + 288, + 122 + ], + "type": "text", + "content": ", i.e., multiple tasks are given at the current time. Otherwise, we have " + }, + { + "bbox": [ + 46, + 72, + 288, + 122 + ], + "type": "inline_equation", + "content": "\\mathbf{d}^{*} = \\mathbf{g}_{1}" + }, + { + "bbox": [ + 46, + 72, + 288, + 122 + ], + "type": "text", + "content": " for the only current task 1. Thus, the final gradient " + }, + { + "bbox": [ + 46, + 72, + 288, + 122 + ], + "type": "inline_equation", + "content": "\\mathbf{d}^{*}" + }, + { + "bbox": [ + 46, + 72, + 288, + 122 + ], + "type": "text", + "content": " is computed by" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 59, + 129, + 287, + 184 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 129, + 287, + 184 + ], + "spans": [ + { + "bbox": [ + 59, + 129, + 287, + 184 + ], + "type": "interline_equation", + "content": "\\mathbf {d} ^ {*} = \\left\\{ \\begin{array}{l l} \\mathbf {g} _ {1}, & | \\mathcal {T} | = 1, \\\\ \\sum_ {i} \\left(\\frac {1}{| \\mathcal {T} | + 1} \\sum_ {j} \\mathbf {W} _ {j, i} ^ {*}\\right) \\mathbf {g} _ {i}, & | \\mathcal {T} | > 1. \\end{array} \\right. \\tag {6}", + "image_path": "da8981135978a17a0c4fc6d48c97b39527d73c47f7572c383341c4af99815779.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "spans": [ + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "type": "text", + "content": "The detailed algorithm is shown in Algorithm 1. With the rehearsal data stream, our algorithm learns a PCL model through a timeline. At the time " + }, + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "type": "text", + "content": " on the timeline, given a mini-batch " + }, + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "type": "inline_equation", + "content": "\\mathcal{B}" + }, + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "type": "text", + "content": " from each data stream, we compute the corresponding gradients on shared and task-specific parameters. The task-specific parameters are updated directly and the gradients on the shared backbone are collected for computed the final updated gradient " + }, + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "type": "inline_equation", + "content": "\\mathbf{d}" + }, + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "type": "text", + "content": ". By using our MaxDO, we update the shared parameters " + }, + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "type": "text", + "content": " with the optimal " + }, + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "type": "inline_equation", + "content": "\\mathbf{d}^*" + }, + { + "bbox": [ + 46, + 192, + 289, + 301 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 312, + 124, + 326 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 312, + 124, + 326 + ], + "spans": [ + { + "bbox": [ + 47, + 312, + 124, + 326 + ], + "type": "text", + "content": "4. Experiment" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 331, + 107, + 344 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 331, + 107, + 344 + ], + "spans": [ + { + "bbox": [ + 47, + 331, + 107, + 344 + ], + "type": "text", + "content": "4.1. Dataset" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 350, + 289, + 494 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 350, + 289, + 494 + ], + "spans": [ + { + "bbox": [ + 46, + 350, + 289, + 494 + ], + "type": "text", + "content": "In our experiments, 3 traditional image recognition datasets are transformed into parallel data streams: (1) Parallel Split EMNIST (PS-EMNIST). We split EMNIST [13] (62 classes) into 5 tasks and the size of the label set for each task, i.e., the number of classes, is set to \\{12, 12, 12, 13, 13\\}. (2) Parallel Split CIFAR-100 (PS-CIFAR-100). We split CIFAR-100 into 10 tasks and the size of the label set for each task is set to 10. (3) Parallel Split ImageNet-TINY (PS-ImageNet-TINY). We split Tiny ImageNet [26] (200 classes) into 10 tasks, and the size of the label set for each task is set to 20. We evaluate PCL on task-incremental and class-incremental scenarios. Please see Appendix for more dataset details." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 495, + 288, + 592 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 495, + 288, + 592 + ], + "spans": [ + { + "bbox": [ + 46, + 495, + 288, + 592 + ], + "type": "text", + "content": "All three datasets have 3 different label sets (3 different class splits), each of which has 3 different timelines (when to access). For each timeline, we have 3 different runs with fixed seeds 1234, 1235, and 1236 for parameter initialization. In other words, we have 27 different settings for each dataset, and we report the average and standard deviation (avg " + }, + { + "bbox": [ + 46, + 495, + 288, + 592 + ], + "type": "inline_equation", + "content": "\\pm" + }, + { + "bbox": [ + 46, + 495, + 288, + 592 + ], + "type": "text", + "content": " std) for each compared method in our experiments. Note that, we omit all blank time that no data stream flows for simplicity." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 599, + 162, + 612 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 599, + 162, + 612 + ], + "spans": [ + { + "bbox": [ + 47, + 599, + 162, + 612 + ], + "type": "text", + "content": "4.2. Experiment Details" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 617, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 289, + 715 + ], + "type": "text", + "content": "We implement our experiments using Tensorflow and conduct on a single NVidia RTX 3090Ti GPU card. We take a 2-layer MLP as the backbone network for PS-EMNIST and a Resnet-18 [22] for PS-CIFAR-100 and PS-ImageNet-Tiny. The learning rate is set to 0.003, 0.0004 and 0.0005 for PS-EMNIST, PS-CIFAR-100 and PS-ImageNet-Tiny. The SGD in MaxDO has a learning rate of 5. Each task is trained in a data stream, i.e., each data point passes only once. For each" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 306, + 74, + 426, + 186 + ], + "blocks": [ + { + "bbox": [ + 306, + 74, + 426, + 186 + ], + "lines": [ + { + "bbox": [ + 306, + 74, + 426, + 186 + ], + "spans": [ + { + "bbox": [ + 306, + 74, + 426, + 186 + ], + "type": "image", + "image_path": "1ae8de300461d0b1ceda8b92b66ef17a7b1dd0cee77b568ac8ba6ba7f66e7f75.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 326, + 189, + 523, + 201 + ], + "lines": [ + { + "bbox": [ + 326, + 189, + 523, + 201 + ], + "spans": [ + { + "bbox": [ + 326, + 189, + 523, + 201 + ], + "type": "text", + "content": "Figure 4. Different memory sizes on PS-CIFAR-100." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 426, + 74, + 542, + 186 + ], + "blocks": [ + { + "bbox": [ + 426, + 74, + 542, + 186 + ], + "lines": [ + { + "bbox": [ + 426, + 74, + 542, + 186 + ], + "spans": [ + { + "bbox": [ + 426, + 74, + 542, + 186 + ], + "type": "image", + "image_path": "4fff1c78cc545be1a217d1ffa6e29e7ae4fbebcde1ad6dcbb68e42c55236c811.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 220, + 545, + 255 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 220, + 545, + 255 + ], + "spans": [ + { + "bbox": [ + 304, + 220, + 545, + 255 + ], + "type": "text", + "content": "task, we set the batch size to 128 per step. For any new task in PCL, we build a new classifier, which is a fully-connected layer with a softmax function." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 256, + 547, + 305 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 256, + 547, + 305 + ], + "spans": [ + { + "bbox": [ + 304, + 256, + 547, + 305 + ], + "type": "text", + "content": "To evaluate PCL, we compute the average accuracy and forgetting, following previous continual learning studies [31, 9, 3, 2, 37]. Let " + }, + { + "bbox": [ + 304, + 256, + 547, + 305 + ], + "type": "inline_equation", + "content": "e_t" + }, + { + "bbox": [ + 304, + 256, + 547, + 305 + ], + "type": "text", + "content": " be the end time of task " + }, + { + "bbox": [ + 304, + 256, + 547, + 305 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 256, + 547, + 305 + ], + "type": "text", + "content": " and the final time " + }, + { + "bbox": [ + 304, + 256, + 547, + 305 + ], + "type": "inline_equation", + "content": "\\bar{e} = \\max(e_1, e_2, \\dots, e_T)" + }, + { + "bbox": [ + 304, + 256, + 547, + 305 + ], + "type": "text", + "content": ", the two metrics are computed as:" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 341, + 312, + 545, + 346 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 341, + 312, + 545, + 346 + ], + "spans": [ + { + "bbox": [ + 341, + 312, + 545, + 346 + ], + "type": "interline_equation", + "content": "A _ {\\bar {e}} = \\frac {1}{T} \\sum_ {t = 1} ^ {T} a _ {\\bar {e}} ^ {t}, \\quad F _ {\\bar {e}} = \\frac {1}{T} \\sum_ {t = 1} ^ {T} a _ {\\bar {e}} ^ {t} - a _ {e _ {t}} ^ {t}, \\tag {7}", + "image_path": "55064778576c089179c1799b46c5547f8c62310d2c0444e29684ba1b341be92d.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "spans": [ + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "type": "inline_equation", + "content": "a_{k}^{j}" + }, + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "type": "text", + "content": " is the mean testing accuracy of task " + }, + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "type": "text", + "content": " at time " + }, + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "type": "inline_equation", + "content": "A_{\\bar{e}}" + }, + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "type": "text", + "content": " denotes the final average accuracy on all the tasks, and " + }, + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "type": "inline_equation", + "content": "F_{\\bar{e}}" + }, + { + "bbox": [ + 305, + 352, + 547, + 401 + ], + "type": "text", + "content": " (also known as backward transfer) means the final performance drop compared to each task that was first trained." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 407, + 391, + 419 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 407, + 391, + 419 + ], + "spans": [ + { + "bbox": [ + 306, + 407, + 391, + 419 + ], + "type": "text", + "content": "4.3. Main Results" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 426, + 547, + 557 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 426, + 547, + 557 + ], + "spans": [ + { + "bbox": [ + 304, + 426, + 547, + 557 + ], + "type": "text", + "content": "We compare our method with MTL methods including MGDA [15], GradNorm [11], DWA [30], GradDrop [12], PCGrad [50] and RLW [28] in the PCL setting. We treat any time on the timeline as an MTL subunit to train PCL. All results of previous MTL methods are produced by ourselves with the claimed design in their papers. We also compare with some rehearsal-based SCL methods including AGEM[9], GMED[37] and ER[10]. To adapt to the SCL methods, we merge batches from every in-training task to mimic a naive sequence learning that only a batch from the current task and a batch from the memory buffer." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 558, + 548, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 548, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 548, + 713 + ], + "type": "text", + "content": "We show the main comparisons with the proposed methods in Tables 1 and 2 on the three datasets. We have several major observations. First, the rehearsal strategy is useful for reducing catastrophic forgetting in PCL for all compared methods. As an extra data stream apart from in-training data streams, rehearsal provides data from the finished tasks training together with other tasks to suppress forgetting. With the rehearsal strategy, the memory may provide continual learning of finished tasks, and even better performance can be obtained, which results in positive forgetting values on " + }, + { + "bbox": [ + 304, + 558, + 548, + 713 + ], + "type": "inline_equation", + "content": "F_{\\bar{e}}" + }, + { + "bbox": [ + 304, + 558, + 548, + 713 + ], + "type": "text", + "content": ". Second, without task-id, class-incremental PCL has worse performance than task-incremental PCL. Surprisingly, we find that MGDA has good performance than other methods in" + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "11416" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 80, + 547, + 225 + ], + "blocks": [ + { + "bbox": [ + 175, + 69, + 415, + 79 + ], + "lines": [ + { + "bbox": [ + 175, + 69, + 415, + 79 + ], + "spans": [ + { + "bbox": [ + 175, + 69, + 415, + 79 + ], + "type": "text", + "content": "Table 1. Task-incremental comparisons (avg ± std) on 3 datasets." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 80, + 547, + 225 + ], + "lines": [ + { + "bbox": [ + 50, + 80, + 547, + 225 + ], + "spans": [ + { + "bbox": [ + 50, + 80, + 547, + 225 + ], + "type": "table", + "html": "
Method (+ Reherasal)TypePS-EMNISTPS-CIFAR-100PS-ImageNet-TINY
A̅̅ (‰)F̅̅ (‰)A̅̅ (‰)F̅̅ (‰)A̅̅ (‰)F̅̅ (‰)
AvgGradMTL89.344 ± 0.231-5.287 ± 0.21647.579 ± 0.08923.691 ± 0.43238.392 ± 0.0760.764 ± 0.139
MGDA [15]MTL84.887 ± 0.469-4.301 ± 0.81848.957 ± 0.45125.088 ± 0.20338.058 ± 0.7401.465 ± 0.490
GradNorm [11]MTL87.888 ± 0.158-6.197 ± 0.18347.210 ± 1.32323.474 ± 0.68838.226 ± 0.7691.647 ± 0.667
DWA [30]MTL88.405 ± 0.322-5.452 ± 0.33844.969 ± 0.37822.682 ± 0.53734.290 ± 1.099-1.053 ± 0.866
PCGrad [50]MTL89.698 ± 0.164-4.921 ± 0.12147.026 ± 0.53823.244 ± 0.74039.427 ± 1.2752.017 ± 0.769
RLW [28]MTL89.288 ± 0.218-5.226 ± 0.20447.574 ± 0.34923.833 ± 0.11738.531 ± 1.6101.332 ± 1.148
AGEM [9]SCL87.022 ± 0.519-7.646 ± 0.48327.379 ± 0.5855.416 ± 0.85128.530 ± 0.994-7.070 ± 1.410
GMED [37]SCL85.471 ± 0.324-8.875 ± 0.33549.094 ± 1.79218.356 ± 1.34534.495 ± 1.568-0.640 ± 1.799
ER [10]SCL89.106 ± 0.315-5.525 ± 0.20747.324 ± 0.58423.330 ± 0.76235.950 ± 0.763-0.767 ± 0.591
MaxDO (AGD)PCL90.189 ± 0.314-4.258 ± 0.31150.203 ± 0.97824.510 ± 0.09240.770 ± 0.3543.119 ± 0.450
", + "image_path": "cea4a168931b6ecf7be8859b4b087d1b3274312d72ccb7268287f0325a47f23c.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "table", + "bbox": [ + 50, + 246, + 545, + 388 + ], + "blocks": [ + { + "bbox": [ + 173, + 236, + 416, + 246 + ], + "lines": [ + { + "bbox": [ + 173, + 236, + 416, + 246 + ], + "spans": [ + { + "bbox": [ + 173, + 236, + 416, + 246 + ], + "type": "text", + "content": "Table 2. Class-incremental comparisons (avg " + }, + { + "bbox": [ + 173, + 236, + 416, + 246 + ], + "type": "inline_equation", + "content": "\\pm" + }, + { + "bbox": [ + 173, + 236, + 416, + 246 + ], + "type": "text", + "content": " std) on 3 datasets." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 246, + 545, + 388 + ], + "lines": [ + { + "bbox": [ + 50, + 246, + 545, + 388 + ], + "spans": [ + { + "bbox": [ + 50, + 246, + 545, + 388 + ], + "type": "table", + "html": "
Method (+ Reherasal)TypePS-EMNISTPS-CIFAR-100PS-ImageNet-TINY
A̅e(%)F̅e(%)A̅e(%)F̅e(%)A̅e(%)F̅e(%)
AvgGradMTL43.823 ± 0.566-44.484 ± 0.5968.921 ± 0.276-4.985 ± 0.7027.511 ± 0.661-15.825 ± 0.228
MGDA [15]MTL52.823 ± 0.201-7.753 ± 0.53811.323 ± 0.282-4.065 ± 0.7258.318 ± 0.155-13.118 ± 0.739
GradNorm [11]MTL43.292 ± 0.590-44.824 ± 0.6889.477 ± 0.222-4.403 ± 1.2366.395 ± 0.130-15.869 ± 0.336
DWA [30]MTL42.734 ± 0.211-38.944 ± 0.5813.519 ± 0.116-7.470 ± 0.2443.003 ± 0.139-12.774 ± 0.158
PCGrad [50]MTL45.035 ± 0.273-43.309 ± 0.17610.140 ± 0.253-5.149 ± 0.5537.789 ± 0.237-15.860 ± 0.318
RLW [28]MTL44.595 ± 0.480-43.424 ± 0.3259.957 ± 0.135-5.173 ± 0.6137.419 ± 0.258-16.079 ± 0.255
AGEM [9]SCL26.249 ± 0.511-62.480 ± 0.5273.374 ± 0.098-10.462 ± 0.5433.379 ± 0.149-18.514 ± 0.516
GMED [37]SCL22.694 ± 0.153-65.805 ± 0.2554.941 ± 0.407-12.837 ± 0.7103.386 ± 0.348-19.060 ± 0.682
ER [10]SCL43.474 ± 0.860-44.597 ± 0.8619.317 ± 0.339-5.337 ± 0.6266.126 ± 0.277-13.686 ± 0.290
MaxDO (AGD)PCL53.139 ± 0.156-11.903 ± 0.47612.237 ± 0.176-2.280 ± 0.2709.532 ± 0.363-12.511 ± 0.610
", + "image_path": "feb92a33b6857604b56a3444d1dafb174b1d163dcf05e30ac3b7b7e21f886eee.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_body" + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "spans": [ + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "type": "text", + "content": "class-incremental PCL compared with the task-incremental scenario, which means the suppressing on catastrophic forgetting is more important in class-incremental PCL. Third, the compared MTL methods are designed for balanced training and ignore the diverse training process in PCL, thus some gradients may be counteracted because of the large gradient discrepancy when updating the model. In contrast, our MaxDO with AGD obtains the best final accuracy " + }, + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "type": "inline_equation", + "content": "A^T" + }, + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "type": "text", + "content": " on three datasets and two scenarios, which shows our superiority in balancing plasticity and stability. For example, we have " + }, + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "type": "inline_equation", + "content": "40.770\\%" + }, + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "type": "inline_equation", + "content": "9.431\\%" + }, + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "type": "text", + "content": " for PS-ImageNet-TINY on two scenarios respectively, while the compared best value is only " + }, + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "type": "inline_equation", + "content": "39.427\\%" + }, + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "type": "inline_equation", + "content": "8.318\\%" + }, + { + "bbox": [ + 47, + 410, + 290, + 649 + ], + "type": "text", + "content": ". On one hand, the proposed AGD is used to measure the asymmetric distance between gradients to boost the effective update of each task. On the other hand, the maximum discrepancies between multiple tasks are reduced. Note that, the forgetting measure of the proposed methods may not outperform the compared methods because we got both better new tasks and final accuracy performance, their difference value may be small." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 658, + 195, + 671 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 658, + 195, + 671 + ], + "spans": [ + { + "bbox": [ + 47, + 658, + 195, + 671 + ], + "type": "text", + "content": "4.4. Rehearsal Analysis in PCL" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 677, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 288, + 715 + ], + "type": "text", + "content": "In Fig. 4, we compare the effects of different memory buffer sizes (per class) in rehearsal on PS-CIFAR-100. We observe that the memory buffer size affects the remembering" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 410, + 547, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 410, + 547, + 555 + ], + "spans": [ + { + "bbox": [ + 304, + 410, + 547, + 555 + ], + "type": "text", + "content": "of old knowledge, and a larger size means better knowledge keeping, which is similar to traditional CL. Under the same memory size, our method has better performance. Then, in Table 3(a), to show the MaxDO's effectiveness of forgetting reduction on rehearsal gradient, we evaluate the result that only leverages MaxDO on new tasks. In this case, the final gradient is calculated by " + }, + { + "bbox": [ + 304, + 410, + 547, + 555 + ], + "type": "inline_equation", + "content": "\\mathbf{d} = \\frac{1}{2}\\mathbf{g}_{\\mathrm{reh}} + \\frac{1}{2}\\mathbf{g}_{\\mathrm{new}}" + }, + { + "bbox": [ + 304, + 410, + 547, + 555 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 410, + 547, + 555 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{new}}" + }, + { + "bbox": [ + 304, + 410, + 547, + 555 + ], + "type": "text", + "content": " is the solution gradient via MaxDO on only new parallel tasks, and " + }, + { + "bbox": [ + 304, + 410, + 547, + 555 + ], + "type": "inline_equation", + "content": "\\mathbf{g}_{\\mathrm{reh}}" + }, + { + "bbox": [ + 304, + 410, + 547, + 555 + ], + "type": "text", + "content": " means the gradient from the rehearsal data streams. The result shows that it is necessary to put the rehearsal gradient to the MaxDO. Otherwise, the model will get worse accuracy and forgetting." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 561, + 503, + 574 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 561, + 503, + 574 + ], + "spans": [ + { + "bbox": [ + 306, + 561, + 503, + 574 + ], + "type": "text", + "content": "4.5. Comparison with Symmetric Metrics" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 579, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 579, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 579, + 547, + 713 + ], + "type": "text", + "content": "As shown in Table 3(b), we compare AGD with three common symmetric metrics including EuDist, CosDist, and Normalized EuDist. EuDist, CosDist are defined in Sec. 3.2. The vanilla EuDist depends highly on the gradient magnitude difference, thus we also compare with its normalized version " + }, + { + "bbox": [ + 304, + 579, + 547, + 713 + ], + "type": "inline_equation", + "content": "D(\\mathbf{x},\\mathbf{y}) = \\frac{\\|\\mathbf{x} - \\mathbf{y}\\|}{\\|\\mathbf{x}\\| + \\|\\mathbf{y}\\|} \\in [0,1]" + }, + { + "bbox": [ + 304, + 579, + 547, + 713 + ], + "type": "text", + "content": ", namely normalized EuDist (Norm EuDist). The results show that the three metrics can also obtain good performance with MaxDO. However, EuDist fails to reduce catastrophic forgetting effectively because of the over-emphasizing of gradient magnitude difference. Considering only the gradient direction difference, MaxDO" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "11417" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 80, + 547, + 222 + ], + "blocks": [ + { + "bbox": [ + 75, + 69, + 515, + 79 + ], + "lines": [ + { + "bbox": [ + 75, + 69, + 515, + 79 + ], + "spans": [ + { + "bbox": [ + 75, + 69, + 515, + 79 + ], + "type": "text", + "content": "Table 3. Reherasal experiemtns, comparisons with symmetric metrics and ablation studies in MaxDO on PS-CIFAR-100." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 80, + 547, + 222 + ], + "lines": [ + { + "bbox": [ + 50, + 80, + 547, + 222 + ], + "spans": [ + { + "bbox": [ + 50, + 80, + 547, + 222 + ], + "type": "table", + "html": "
ExperimentMethodTask-incrementClass-increment
A̅e(%)F̅e(%)A̅e(%)F̅e(%)
(a) Rehearsal analysisMaxDO (w/o Rehearsal)25.241 ± 0.4663.128 ± 0.1752.971 ± 0.048-11.356 ± 0.703
MaxDO (w/o Reheerasal gradient)47.653 ± 1.28023.538 ± 1.4689.431 ± 0.469-5.907 ± 0.658
(b) Symmetric metricsMaxDO (EuDist)49.201 ± 0.41024.112 ± 0.19710.189 ± 0.218-7.172 ± 0.796
MaxDO (CosDist)49.154 ± 0.57025.094 ± 0.22211.771 ± 0.139-3.114 ± 0.681
MaxDO (Norm EuDist)48.517 ± 0.33624.386 ± 0.38811.692 ± 0.373-3.228 ± 0.822
(c) Ablation studiesMGDA [15]48.957 ± 0.45125.088 ± 0.20311.323 ± 0.282-4.065 ± 0.725
MaxDO (w/o Max-Discrepancy)47.899 ± 1.02223.874 ± 0.44710.441 ± 0.324-4.807 ± 0.573
MaxDO (w/o MGDA)49.631 ± 0.43125.816 ± 0.56111.881 ± 0.468-2.993 ± 0.964
(d) Our full methodMaxDO (AGD, w/ Reherasal)50.203 ± 0.27424.510 ± 0.09212.237 ± 0.176-2.280 ± 0.270
", + "image_path": "7b850b10ace0dbe2f8465249c04865d9b9bc185f2b83a2a8cfccc6368cee695e.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 48, + 244, + 166, + 353 + ], + "blocks": [ + { + "bbox": [ + 48, + 244, + 166, + 353 + ], + "lines": [ + { + "bbox": [ + 48, + 244, + 166, + 353 + ], + "spans": [ + { + "bbox": [ + 48, + 244, + 166, + 353 + ], + "type": "image", + "image_path": "18d9405b8087426dcf15d0ca9fea6a247f6b347f5598f8ac4f42496dba9479d9.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 101, + 357, + 111, + 365 + ], + "lines": [ + { + "bbox": [ + 101, + 357, + 111, + 365 + ], + "spans": [ + { + "bbox": [ + 101, + 357, + 111, + 365 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 96, + 369, + 235, + 380 + ], + "lines": [ + { + "bbox": [ + 96, + 369, + 235, + 380 + ], + "spans": [ + { + "bbox": [ + 96, + 369, + 235, + 380 + ], + "type": "text", + "content": "Figure 5. Training time comparisons." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 167, + 243, + 284, + 353 + ], + "blocks": [ + { + "bbox": [ + 167, + 243, + 284, + 353 + ], + "lines": [ + { + "bbox": [ + 167, + 243, + 284, + 353 + ], + "spans": [ + { + "bbox": [ + 167, + 243, + 284, + 353 + ], + "type": "image", + "image_path": "5197341081d95afd38ac43bf1b27e759b29e2e5cba2c6a875248ef209fac8e1d.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 219, + 357, + 230, + 365 + ], + "lines": [ + { + "bbox": [ + 219, + 357, + 230, + 365 + ], + "spans": [ + { + "bbox": [ + 219, + 357, + 230, + 365 + ], + "type": "text", + "content": "(b)" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 399, + 288, + 496 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 399, + 288, + 496 + ], + "spans": [ + { + "bbox": [ + 46, + 399, + 288, + 496 + ], + "type": "text", + "content": "with CosDist obtains better performance than EuDist. But CosDist ignores the magnitude difference, which is also important in the min-distance problem, resulting in insufficient performance. Compared to EuDist, normalized EuDist obtains even worse performance. In contrast, MaxDO with AGD considers the asymmetric influence on gradient update, and tolerance is set to reduce the influence from small gradients to new-access tasks, which yields the best performance." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 503, + 141, + 516 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 503, + 141, + 516 + ], + "spans": [ + { + "bbox": [ + 47, + 503, + 141, + 516 + ], + "type": "text", + "content": "4.6. Ablation Study" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 522, + 289, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 522, + 289, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 522, + 289, + 713 + ], + "type": "text", + "content": "We evaluate the impact of the two main components of MaxDO in Table 3(c). First, we block the maximum discrepancy in MaxDO (MaxDO (w/o Max-Discrepancy)), which means that we solve the min-distance problem with Eq. (4) directly. Because of the self-interference, the solution combines the minimum discrepancy but fails to effectively reduce the discrepancy from other gradients (47.899% and 10.441% for " + }, + { + "bbox": [ + 46, + 522, + 289, + 713 + ], + "type": "inline_equation", + "content": "A_{\\bar{e}}" + }, + { + "bbox": [ + 46, + 522, + 289, + 713 + ], + "type": "text", + "content": "). We then block the MGDA that obtains a weighted gradient not damage any tasks. MGDA is quite useful in traditional MTL tasks but is not suitable in PCL (w/o MGDA, 49.693% and 11.881% for " + }, + { + "bbox": [ + 46, + 522, + 289, + 713 + ], + "type": "inline_equation", + "content": "A_{\\bar{e}}" + }, + { + "bbox": [ + 46, + 522, + 289, + 713 + ], + "type": "text", + "content": "). Because of the diverse training process of parallel tasks, gradients are with large magnitude differences and MGDA prefers to set large factors to small gradients. We solve the problem by both MGDA and the maximum discrepancy, and the whole MaxDO method with AGD outperforms the two ablated" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 242, + 547, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 242, + 547, + 266 + ], + "spans": [ + { + "bbox": [ + 304, + 242, + 547, + 266 + ], + "type": "text", + "content": "methods (50.203% and 12.231% for " + }, + { + "bbox": [ + 304, + 242, + 547, + 266 + ], + "type": "inline_equation", + "content": "A_{\\bar{e}}" + }, + { + "bbox": [ + 304, + 242, + 547, + 266 + ], + "type": "text", + "content": "), where the characters of the two components are combined." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 271, + 405, + 283 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 271, + 405, + 283 + ], + "spans": [ + { + "bbox": [ + 305, + 271, + 405, + 283 + ], + "type": "text", + "content": "4.7. Procedure Time" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 290, + 547, + 398 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 290, + 547, + 398 + ], + "spans": [ + { + "bbox": [ + 304, + 290, + 547, + 398 + ], + "type": "text", + "content": "In Fig. 5, we show the training time comparison on PS-CIFAR-100. We first compare the training time for 2 to 5 parallel tasks in one iteration (Fig. 5(a)). We find that the generation of task numbers will grow the training time, and MaxDO needs more time than other methods because multiple minimum distance optimizations are performed. Then, we show both the final accuracy and whole training time in Fig. 5(b). In the whole timeline, MaxDO gets slightly longer training time than other methods but better performance." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 403, + 456, + 416 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 403, + 456, + 416 + ], + "spans": [ + { + "bbox": [ + 305, + 403, + 456, + 416 + ], + "type": "text", + "content": "4.8. Tolerance Analysis in AGD" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 422, + 547, + 541 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 422, + 547, + 541 + ], + "spans": [ + { + "bbox": [ + 304, + 422, + 547, + 541 + ], + "type": "text", + "content": "In our paper, AGD is designed to have a tolerance " + }, + { + "bbox": [ + 304, + 422, + 547, + 541 + ], + "type": "inline_equation", + "content": "\\frac{1}{2}" + }, + { + "bbox": [ + 304, + 422, + 547, + 541 + ], + "type": "text", + "content": " in Corollary 1. This is because updating with a zero gradient will neither improve nor damage the performance. Even though, we prefer positive influence rather than noninfluence. Thus, we define that the distance " + }, + { + "bbox": [ + 304, + 422, + 547, + 541 + ], + "type": "inline_equation", + "content": "\\widehat{D}(\\mathbf{g}_{\\mathrm{A}}, \\mathbf{g}_{\\mathrm{B}})" + }, + { + "bbox": [ + 304, + 422, + 547, + 541 + ], + "type": "text", + "content": " in the situation " + }, + { + "bbox": [ + 304, + 422, + 547, + 541 + ], + "type": "inline_equation", + "content": "\\|\\mathbf{g}_{\\mathrm{A}}\\| \\ll \\|\\mathbf{g}_{\\mathrm{B}}\\|" + }, + { + "bbox": [ + 304, + 422, + 547, + 541 + ], + "type": "text", + "content": " is the mid-level in the value range. Therefore, we study to change the tolerance and observe the performance change. The tolerance can be controlled by adding a factor " + }, + { + "bbox": [ + 304, + 422, + 547, + 541 + ], + "type": "inline_equation", + "content": "\\gamma > 0" + }, + { + "bbox": [ + 304, + 422, + 547, + 541 + ], + "type": "text", + "content": " at the denominator. Omitting the edge situation, we have" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 349, + 546, + 503, + 572 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 349, + 546, + 503, + 572 + ], + "spans": [ + { + "bbox": [ + 349, + 546, + 503, + 572 + ], + "type": "interline_equation", + "content": "\\widehat {D} _ {\\gamma} \\left(\\mathbf {g} _ {\\mathrm {A}}, \\mathbf {g} _ {\\mathrm {B}}\\right) = \\frac {\\| \\mathbf {g} _ {\\mathrm {A}} - \\mathbf {g} _ {\\mathrm {B}} \\|}{\\gamma \\| \\mathbf {g} _ {\\mathrm {B}} \\| + \\| \\mathbf {g} _ {\\mathrm {A}} - \\mathbf {g} _ {\\mathrm {B}} \\Vert}.", + "image_path": "bfe47d0eb5515d16c41c8604af86c77192663d62871f5ee136a0f52cf2f97a5b.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 576, + 547, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 576, + 547, + 613 + ], + "spans": [ + { + "bbox": [ + 304, + 576, + 547, + 613 + ], + "type": "text", + "content": "The experiments on different tolerances are shown in Table 4. The results show either larger or smaller tolerances compared to " + }, + { + "bbox": [ + 304, + 576, + 547, + 613 + ], + "type": "inline_equation", + "content": "\\frac{1}{2}" + }, + { + "bbox": [ + 304, + 576, + 547, + 613 + ], + "type": "text", + "content": " will get the performance drop during the PCL training." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 621, + 379, + 633 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 621, + 379, + 633 + ], + "spans": [ + { + "bbox": [ + 306, + 621, + 379, + 633 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 642, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 547, + 713 + ], + "type": "text", + "content": "In this paper, we studied to address the training conflict and catastrophic forgetting issues in Parallel Continual Learning (PCL). We presented that the two issues are rooted in the gradient discrepancies and formulated the problem into a minimum distance optimization among gradients. However, the distance metric is often set to be symmetric, which" + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "11418" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 80, + 287, + 152 + ], + "blocks": [ + { + "bbox": [ + 72, + 70, + 258, + 79 + ], + "lines": [ + { + "bbox": [ + 72, + 70, + 258, + 79 + ], + "spans": [ + { + "bbox": [ + 72, + 70, + 258, + 79 + ], + "type": "text", + "content": "Table 4. Comparisons on different tolerance (Tol.)." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 80, + 287, + 152 + ], + "lines": [ + { + "bbox": [ + 50, + 80, + 287, + 152 + ], + "spans": [ + { + "bbox": [ + 50, + 80, + 287, + 152 + ], + "type": "table", + "html": "
γTol.Task-incrementClass-increment
A̅e(%)F̅e(%)A̅e(%)F̅e(%)
0.25/646.118 ± 0.46322.617 ± 0.48411.283 ± 0.696-3.158 ± 1.087
0.52/346.452 ± 0.11322.874 ± 0.68011.284 ± 0.343-3.305 ± 0.629
11/250.203 ± 0.27424.510 ± 0.09212.237 ± 0.176-2.280 ± 0.270
21/349.827 ± 0.42025.520 ± 0.61111.603 ± 0.506-3.503 ± 0.687
31/448.766 ± 0.17124.491 ± 0.40611.389 ± 0.738-3.234 ± 1.060
41/548.859 ± 0.62724.714 ± 0.43711.378 ± 0.484-3.189 ± 0.902
", + "image_path": "145f50b6952e5e9e748076c39565d82e6f7dae3e74891d7fe7eabdb1415d0ec7.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 176, + 290, + 392 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 176, + 290, + 392 + ], + "spans": [ + { + "bbox": [ + 47, + 176, + 290, + 392 + ], + "type": "text", + "content": "is problematic in gradient descent. To evaluate the gradient discrepancy in PCL, we proposed an explicit Asymmetric Gradient Distance (AGD), which considers both gradient magnitude ratios and directions and has a tolerance when updating with a small gradient of inverse direction. Moreover, we proposed a novel Maximum Discrepancy Optimization (MaxDO) strategy to minimize the maximum discrepancy among multiple gradients and avoid self-interference. Solving by MaxDO with AGD, the parallel training in PCL reduces the influence of the training conflict and slows the catastrophic forgetting. We verified the proposed method on three image recognition datasets. The experimental results significantly showed the advantage of MaxDO and the effectiveness of the proposed AGD. We list the latent limitation of our method: (1) The MaxDO cannot guarantee a theoretical Pareto optimum in the training process like MGDA, which means a better trade-off can be obtained in the future. (2) The MaxDO method needs more time for training." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 407, + 145, + 421 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 407, + 145, + 421 + ], + "spans": [ + { + "bbox": [ + 47, + 407, + 145, + 421 + ], + "type": "text", + "content": "Acknowledgement" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 430, + 288, + 489 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 430, + 288, + 489 + ], + "spans": [ + { + "bbox": [ + 47, + 430, + 288, + 489 + ], + "type": "text", + "content": "We gratefully acknowledge the invaluable support from the following funding bodies: the National Natural Science Foundation of China (62072334, 62276182), and the National Key Research and Development Program of China (2020YFC1522701)." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 505, + 107, + 517 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 505, + 107, + 517 + ], + "spans": [ + { + "bbox": [ + 48, + 505, + 107, + 517 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 52, + 526, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 11, + "blocks": [ + { + "bbox": [ + 52, + 526, + 287, + 560 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 526, + 287, + 560 + ], + "spans": [ + { + "bbox": [ + 52, + 526, + 287, + 560 + ], + "type": "text", + "content": "[1] Rahaf Aljundi, Francesca Babiloni, Mohamed Elhoseiny, Marcus Rohrbach, and Tinne Tuytelaars. Memory aware synapses: Learning what (not) to forget. In ECCV, 2018. 1, 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 563, + 288, + 605 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 563, + 288, + 605 + ], + "spans": [ + { + "bbox": [ + 53, + 563, + 288, + 605 + ], + "type": "text", + "content": "[2] Rahaf Aljundi, Eugene Belilovsky, Tinne Tuytelaars, Laurent Charlin, Massimo Caccia, Min Lin, and Lucas Page-Caccia. Online continual learning with maximal interfered retrieval. In NeurIPS, 2019. 6" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 609, + 288, + 642 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 609, + 288, + 642 + ], + "spans": [ + { + "bbox": [ + 53, + 609, + 288, + 642 + ], + "type": "text", + "content": "[3] Rahaf Aljundi, Min Lin, Baptiste Goujaud, and Yoshua Bengio. Gradient based sample selection for online continual learning. In NeurlPS, 2019. 6" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 644, + 288, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 644, + 288, + 689 + ], + "spans": [ + { + "bbox": [ + 53, + 644, + 288, + 689 + ], + "type": "text", + "content": "[4] Craig Atkinson, Brendan McCane, Lech Szymanski, and Anthony Robins. Pseudo-rehearsal: Achieving deep reinforcement learning without catastrophic forgetting. arXiv preprint arXiv:1812.02464, 2018. 1, 2, 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 691, + 288, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 691, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 53, + 691, + 288, + 713 + ], + "type": "text", + "content": "[5] Aviad Barzilai and Koby Crammer. Convex multi-task learning by clustering. In AISTATS, 2015. 2" + } + ] + } + ], + "index": 10 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 31, + "blocks": [ + { + "bbox": [ + 312, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 312, + 73, + 545, + 106 + ], + "type": "text", + "content": "[6] Francesca Cagliari, Barbara Di Fabio, and Claudia Landi. The natural pseudo-distance as a quotient pseudo-metric, and applications. In Forum Mathematicum. De Gruyter, 2015. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 312, + 107, + 545, + 118 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 107, + 545, + 118 + ], + "spans": [ + { + "bbox": [ + 312, + 107, + 545, + 118 + ], + "type": "text", + "content": "[7] Rich Caruana. Multitask learning. Machine learning, 1997. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 312, + 119, + 547, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 119, + 547, + 162 + ], + "spans": [ + { + "bbox": [ + 312, + 119, + 547, + 162 + ], + "type": "text", + "content": "[8] Arslan Chaudhry, Puneet K Dokania, Thalaiyasingam Ajthan, and Philip HS Torr. Riemannian walk for incremental learning: Understanding forgetting and intransigence. In ECCV, 2018. 1, 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 312, + 163, + 545, + 196 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 163, + 545, + 196 + ], + "spans": [ + { + "bbox": [ + 312, + 163, + 545, + 196 + ], + "type": "text", + "content": "[9] Arslan Chaudhry, Marc'Aurelio Ranzato, Marcus Rohrbach, and Mohamed Elhoseiny. Efficient lifelong learning with a-gem. In ICLR, 2019. 1, 2, 3, 6, 7" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 198, + 545, + 241 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 198, + 545, + 241 + ], + "spans": [ + { + "bbox": [ + 307, + 198, + 545, + 241 + ], + "type": "text", + "content": "[10] Arslan Chaudhry, Marcus Rohrbach, Mohamed Elhoseiny, Thalaiyasingam Ajanthan, Puneet K Dokania, Philip H S Torr, and Marcurelio Ranzato. On tiny episodic memories in continual learning. arXiv: Learning, 2019. 6, 7" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 242, + 545, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 242, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 308, + 242, + 545, + 285 + ], + "type": "text", + "content": "[11] Zhao Chen, Vijay Badrinarayanan, Chen-Yu Lee, and Andrew Rabinovich. Gradnorm: Gradient normalization for adaptive loss balancing in deep multitask networks. In ICML, 2018. 2, 6, 7" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 286, + 545, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 286, + 545, + 330 + ], + "spans": [ + { + "bbox": [ + 308, + 286, + 545, + 330 + ], + "type": "text", + "content": "[12] Zhao Chen, Jiquan Ngiam, Yanping Huang, Thang Luong, Henrik Kretzschmar, Yuning Chai, and Dragomir Anguelov. Just pick a sign: Optimizing deep multitask models with gradient sign dropout. In NeurIPS, 2020. 2, 6" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 331, + 545, + 363 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 331, + 545, + 363 + ], + "spans": [ + { + "bbox": [ + 308, + 331, + 545, + 363 + ], + "type": "text", + "content": "[13] Gregory Cohen, Saeed Afshar, Jonathan Tapson, and Andre Van Schaik. Emmist: Extending mnist to handwritten letters. In IJCNN, 2017. 6" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 365, + 545, + 387 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 365, + 545, + 387 + ], + "spans": [ + { + "bbox": [ + 308, + 365, + 545, + 387 + ], + "type": "text", + "content": "[14] Julia Collins and Johannes Zimmer. An asymmetric arzelà-ascoli theorem. Topology and its Applications, 2007. 3, 4" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 388, + 545, + 421 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 388, + 545, + 421 + ], + "spans": [ + { + "bbox": [ + 308, + 388, + 545, + 421 + ], + "type": "text", + "content": "[15] Jean-Antoine Désideri. Multiple-gradient descent algorithm (mgda) for multiobjective optimization. Comptes Rendus Mathematique, 2012. 5, 6, 7, 8" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 422, + 545, + 454 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 422, + 545, + 454 + ], + "spans": [ + { + "bbox": [ + 308, + 422, + 545, + 454 + ], + "type": "text", + "content": "[16] Prithviraj Dhar, Rajat Vikram Singh, Kuan-Chuan Peng, Ziyan Wu, and Rama Chellappa. Learning without memorizing. In CVPR, 2019. 1, 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 456, + 545, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 456, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 308, + 456, + 545, + 487 + ], + "type": "text", + "content": "[17] Mehrdad Farajtabar, Navig Azizan, Alex Mott, and Ang Li. Orthogonal gradient descent for continual learning. In AISTATS, 2020. 2" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 488, + 545, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 488, + 545, + 510 + ], + "spans": [ + { + "bbox": [ + 308, + 488, + 545, + 510 + ], + "type": "text", + "content": "[18] MA Fiol. On pseudo-distance-regularity. Linear Algebra and its Applications, 2001. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 512, + 545, + 533 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 512, + 545, + 533 + ], + "spans": [ + { + "bbox": [ + 308, + 512, + 545, + 533 + ], + "type": "text", + "content": "[19] Robert M French. Catastrophic forgetting in connectionist networks. TiCS, 1999. 1" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 535, + 545, + 567 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 535, + 545, + 567 + ], + "spans": [ + { + "bbox": [ + 308, + 535, + 545, + 567 + ], + "type": "text", + "content": "[20] Rick Groenendijk, Sezer Karaoglu, Theo Gevers, and Thomas Mensink. Multi-loss weighting with coefficient of variations. In WACV, 2021. 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 568, + 545, + 611 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 568, + 545, + 611 + ], + "spans": [ + { + "bbox": [ + 308, + 568, + 545, + 611 + ], + "type": "text", + "content": "[21] Yunhui Guo, Mingrui Liu, Tianbao Yang, and Tajana Rosing. Learning with long-term remembering: Following the lead of mixed stochastic gradient. arXiv preprint arXiv:1909.11763, 2019. 1, 2, 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 613, + 545, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 613, + 545, + 645 + ], + "spans": [ + { + "bbox": [ + 308, + 613, + 545, + 645 + ], + "type": "text", + "content": "[22] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, 2016. 6" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 647, + 545, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 647, + 545, + 678 + ], + "spans": [ + { + "bbox": [ + 308, + 647, + 545, + 678 + ], + "type": "text", + "content": "[23] Ali Jalali, Sujay Sanghavi, Chao Ruan, and Pradeep Ravikumar. A dirty model for multi-task learning. In NeurIPS, 2010. 2" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 308, + 680, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 680, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 680, + 545, + 713 + ], + "type": "text", + "content": "[24] Adrián Javaloy and Isabel Valera. Rotograd: Gradient homogenization in multitask learning. arXiv preprint arXiv:2103.02631, 2021. 2" + } + ] + } + ], + "index": 30 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "text", + "content": "11419" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 712 + ], + "type": "list", + "angle": 0, + "index": 20, + "blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 127 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 288, + 127 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 288, + 127 + ], + "type": "text", + "content": "[25] James Kirkpatrick, Razvan Pascanu, Neil Rabinowitz, Joel Veness, Guillaume Desjardins, Andrei A Rusu, Kieran Milan, John Quan, Tiago Ramalho, Agnieszka Grabska-Barwinska, et al. Overcoming catastrophic forgetting in neural networks. PNAS, 2017. 1, 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 128, + 288, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 128, + 288, + 150 + ], + "spans": [ + { + "bbox": [ + 48, + 128, + 288, + 150 + ], + "type": "text", + "content": "[26] Ya Le and Xuan Yang. Tiny imagenet visual recognition challenge. CS 231N, 2015. 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 150, + 288, + 171 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 150, + 288, + 171 + ], + "spans": [ + { + "bbox": [ + 48, + 150, + 288, + 171 + ], + "type": "text", + "content": "[27] Zhizhong Li and Derek Hoiem. Learning without forgetting. TPAMI, 2017. 1" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 172, + 288, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 172, + 288, + 205 + ], + "spans": [ + { + "bbox": [ + 48, + 172, + 288, + 205 + ], + "type": "text", + "content": "[28] Baijiong Lin, Feiyang Ye, and Yu Zhang. A closer look at loss weighting in multi-task learning. arXiv preprint arXiv:2111.10603, 2021. 2, 4, 6, 7" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 205, + 288, + 237 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 205, + 288, + 237 + ], + "spans": [ + { + "bbox": [ + 48, + 205, + 288, + 237 + ], + "type": "text", + "content": "[29] Bo Liu, Xingchao Liu, Xiaojie Jin, Peter Stone, and Qiang Liu. Conflict-averse gradient descent for multi-task learning. In NeurIPS, 2021. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 238, + 288, + 270 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 238, + 288, + 270 + ], + "spans": [ + { + "bbox": [ + 48, + 238, + 288, + 270 + ], + "type": "text", + "content": "[30] Shikun Liu, Edward Johns, and Andrew J Davison. End-to-end multi-task learning with attention. In CVPR, 2019. 2, 6, 7" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 271, + 288, + 303 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 271, + 288, + 303 + ], + "spans": [ + { + "bbox": [ + 48, + 271, + 288, + 303 + ], + "type": "text", + "content": "[31] David Lopez-Paz and Marc'Aurelio Ranzato. Gradient episodic memory for continual learning. In NeurIPS, 2017. 1, 2, 3, 6" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 304, + 288, + 338 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 304, + 288, + 338 + ], + "spans": [ + { + "bbox": [ + 48, + 304, + 288, + 338 + ], + "type": "text", + "content": "[32] Fan Lyu, Shuai Wang, Wei Feng, Zihan Ye, Fuyuan Hu, and Song Wang. Multi-domain multi-task rehearsal for lifelong learning. In AAAI, 2021. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 338, + 288, + 370 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 338, + 288, + 370 + ], + "spans": [ + { + "bbox": [ + 48, + 338, + 288, + 370 + ], + "type": "text", + "content": "[33] Arun Mallya, Dillon Davis, and Svetlana Lazebnik. Piggyback: Adapting a single network to multiple tasks by learning to mask weights. In ECCV, 2018. 1, 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 371, + 288, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 371, + 288, + 403 + ], + "spans": [ + { + "bbox": [ + 48, + 371, + 288, + 403 + ], + "type": "text", + "content": "[34] Andreas Maurer, Massi Pontil, and Bernardino Romero-Paredes. Sparse coding for multitask and transfer learning. In ICML, 2013. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 404, + 288, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 404, + 288, + 426 + ], + "spans": [ + { + "bbox": [ + 48, + 404, + 288, + 426 + ], + "type": "text", + "content": "[35] Andrea CG Mennucci. On asymmetric distances. Analysis and Geometry in Metric Spaces, 2013. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 426, + 288, + 459 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 426, + 288, + 459 + ], + "spans": [ + { + "bbox": [ + 48, + 426, + 288, + 459 + ], + "type": "text", + "content": "[36] Jary Pomponi, Simone Scardapane, and Aurelio Uncini. Pseudo-rehearsal for continual learning with normalizing flows. arXiv preprint arXiv:2007.02443, 2020. 1, 2, 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 459, + 288, + 492 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 459, + 288, + 492 + ], + "spans": [ + { + "bbox": [ + 48, + 459, + 288, + 492 + ], + "type": "text", + "content": "[37] Liu Risheng, Liu Yaohua, Zeng Shangzhi, and Jin Zhang. Gradient-based editing of memory examples for online task-free continual learning. In NeurIPS, 2021. 6, 7" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 492, + 288, + 515 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 492, + 288, + 515 + ], + "spans": [ + { + "bbox": [ + 48, + 492, + 288, + 515 + ], + "type": "text", + "content": "[38] Amir Rosenfeld and John K Tsotsos. Incremental learning through deep adaptation. TPAMI, 2018. 1, 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 515, + 288, + 558 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 515, + 288, + 558 + ], + "spans": [ + { + "bbox": [ + 48, + 515, + 288, + 558 + ], + "type": "text", + "content": "[39] Andrei A Rusu, Neil C Rabinowitz, Guillaume Desjardins, Hubert Soyer, James Kirkpatrick, Koray Kavukcuoglu, Razvan Pascanu, and Raia Hadsell. Progressive neural networks. arXiv preprint arXiv:1606.04671, 2016. 1, 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 559, + 288, + 581 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 559, + 288, + 581 + ], + "spans": [ + { + "bbox": [ + 48, + 559, + 288, + 581 + ], + "type": "text", + "content": "[40] Ozan Sener and Vladlen Koltun. Multi-task learning as multi-objective optimization. In NeurIPS, 2018. 2, 4" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 581, + 288, + 613 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 581, + 288, + 613 + ], + "spans": [ + { + "bbox": [ + 48, + 581, + 288, + 613 + ], + "type": "text", + "content": "[41] Haseeb Shah, Khurram Javed, and Faisal Shafait. Distillation techniques for pseudo-rehearsal based incremental learning. arXiv preprint arXiv:1807.02799, 2018. 1, 2, 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 48, + 614, + 288, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 614, + 288, + 646 + ], + "spans": [ + { + "bbox": [ + 48, + 614, + 288, + 646 + ], + "type": "text", + "content": "[42] Donald Shenaj, Marco Toldo, Alberto Rigon, and Pietro Zanuttigh. Asynchronous federated continual learning. In CVPR, 2023. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 48, + 647, + 288, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 288, + 679 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 288, + 679 + ], + "type": "text", + "content": "[43] Qing Sun, Fan Lyu, Fanhua Shang, Wei Feng, and Liang Wan. Exploring example influence in continual learning. *NeurIPS*, 2022. 1" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 48, + 680, + 288, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 680, + 288, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 680, + 288, + 712 + ], + "type": "text", + "content": "[44] Sebastian Thrun and Joseph O'Sullivan. Discovering structure in multiple learning tasks: The tc algorithm. In ICML, 1996. 2" + } + ] + } + ], + "index": 19 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 72, + 547, + 310 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 307, + 72, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 72, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 307, + 72, + 545, + 95 + ], + "type": "text", + "content": "[45] Jie Wang and Jieping Ye. Safe screening for multi-task feature learning with multiple data matrices. In ICML, 2015. 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 96, + 547, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 96, + 547, + 140 + ], + "spans": [ + { + "bbox": [ + 307, + 96, + 547, + 140 + ], + "type": "text", + "content": "[46] Zirui Wang, Yulia Tsvetkov, Orhan Firat, and Yuan Cao. Gradient vaccine: Investigating and improving multi-task optimization in massively multilingual models. arXiv preprint arXiv:2010.05874, 2020. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 141, + 545, + 163 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 141, + 545, + 163 + ], + "spans": [ + { + "bbox": [ + 307, + 141, + 545, + 163 + ], + "type": "text", + "content": "[47] Wallace Alvin Wilson. On quasi-metric spaces. American Journal of Mathematics, 1931. 4" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 164, + 545, + 196 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 164, + 545, + 196 + ], + "spans": [ + { + "bbox": [ + 307, + 164, + 545, + 196 + ], + "type": "text", + "content": "[48] Jaehong Yoon, Wonyong Jeong, Giwoong Lee, Eunho Yang, and Sung Ju Hwang. Federated continual learning with weighted inter-client transfer. In ICML, 2021. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 198, + 545, + 230 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 198, + 545, + 230 + ], + "spans": [ + { + "bbox": [ + 307, + 198, + 545, + 230 + ], + "type": "text", + "content": "[49] Jaehong Yoon, Eunho Yang, Jeongtae Lee, and Sung Ju Hwang. Lifelong learning with dynamically expandable networks. arXiv preprint arXiv:1708.01547, 2017. 1, 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 232, + 545, + 265 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 232, + 545, + 265 + ], + "spans": [ + { + "bbox": [ + 307, + 232, + 545, + 265 + ], + "type": "text", + "content": "[50] Tianhe Yu, Saurabh Kumar, Abhishek Gupta, Sergey Levine, Karol Hausman, and Chelsea Finn. Gradient surgery for multi-task learning. In NeurIPS, 2020. 1, 2, 3, 6, 7" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 266, + 545, + 288 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 266, + 545, + 288 + ], + "spans": [ + { + "bbox": [ + 307, + 266, + 545, + 288 + ], + "type": "text", + "content": "[51] Friedemann Zenke, Ben Poole, and Surya Ganguli. Continual learning through synaptic intelligence. In ICML, 2017. 1, 2" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 289, + 545, + 310 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 289, + 545, + 310 + ], + "spans": [ + { + "bbox": [ + 307, + 289, + 545, + 310 + ], + "type": "text", + "content": "[52] Yu Zhang and Qiang Yang. A survey on multi-task learning. IEEE TKDE, 2021. 2" + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "11420" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/a294a7d4-55de-429f-8329-44c18b938170_content_list.json b/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/a294a7d4-55de-429f-8329-44c18b938170_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..aa3c025795525ab81e223a999a8095a22246f01e --- /dev/null +++ b/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/a294a7d4-55de-429f-8329-44c18b938170_content_list.json @@ -0,0 +1,1773 @@ +[ + { + "type": "text", + "text": "MedKLIP: Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis", + "text_level": 1, + "bbox": [ + 184, + 130, + 785, + 176 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Chaoyi Wu $^{1,2}$ , Xiaoman Zhang $^{1,2}$ , Ya Zhang $^{1,2}$ , Yanfeng Wang $^{1,2,\\dagger}$ , Weidi Xie $^{1,2,\\dagger}$ $^{1}$ Cooperative Medianet Innovation Center, Shanghai Jiao Tong University $^{2}$ Shanghai AI Laboratory $\\{\\mathrm{wtzxxxxwcy02, xm99sjtu, ya_zhang, wangyanfeng, weidi}\\} \\mathrm{sjtu.edu.cn}$ https://chaoyi-wu.github.io/MedKLIP/", + "bbox": [ + 86, + 200, + 890, + 275 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 309, + 313, + 325 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In this paper, we consider enhancing medical visual-language pre-training (VLP) with domain-specific knowledge, by exploiting the paired image-text reports from the radiological daily practice. In particular, we make the following contributions: First, unlike existing works that directly process the raw reports, we adopt a novel triplet extraction module to extract the medical-related information, avoiding unnecessary complexity from language grammar and enhancing the supervision signals; Second, we propose a novel triplet encoding module with entity translation by querying a knowledge base, to exploit the rich domain knowledge in medical field, and implicitly build relationships between medical entities in the language embedding space; Third, we propose to use a Transformer-based fusion model for spatially aligning the entity description with visual signals at the image patch level, enabling the ability for medical diagnosis; Fourth, we conduct thorough experiments to validate the effectiveness of our architecture, and benchmark on numerous public benchmarks e.g., ChestX-ray14, RSNA Pneumonia, SIIM-ACR Pneumothorax, COVIDx CXR-2, COVID Rural, and EdemaSeverity. In both zero-shot and fine-tuning settings, our model has demonstrated strong performance compared with the former methods on disease classification and grounding.", + "bbox": [ + 76, + 340, + 473, + 704 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 731, + 209, + 747 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "With the rapid development of deep learning, numerous works have been proposed to facilitate computer-aided diagnosis in the medical field [46, 20, 55, 19]. Despite the tremendous progress, these models are normally trained to recognize or segment the structures that fall into a certain closed set of anatomical or disease categories, whenever a new disease comes to be of interest, a costly procedure for data annotation, model re-training are required, fundamen", + "bbox": [ + 75, + 756, + 468, + 878 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/776a2a2efcaae6e8ffac6dacfa1af20fdde1eaf463fe0e458d69a7b3c2c0ab70.jpg", + "image_caption": [ + "Figure 1: Our method mainly considers combining medical knowledge with VLP. We propose Triplet Extraction and Entity Translation modules, so that the network can be supervised with detailed entity-level signals." + ], + "image_footnote": [], + "bbox": [ + 501, + 308, + 890, + 429 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "tally limiting its practical values. As an alternative, recent research considers to train the model on the corpus, consisting of large amount of multi-modal data, that is generated from daily clinical routine, for instance, the most common example is the dataset of X-ray images with paired radiological reports [18, 28, 31].", + "bbox": [ + 496, + 518, + 892, + 611 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "This paper presents our preliminary investigation on vision-language representation learning in the medical domain, with the goal of better zero-shot disease diagnosis (classification) and grounding. Undoubtedly, these tasks have also been widely investigated in the computer vision community, with significant progress made on developing Foundational Models in the past years, for example, CLIP [50], ALBEF [33], BLIP[32], etc. However, to achieve such a goal in the medical domain, different challenges must be resolved, that requires research efforts from the community: First, data availability, training Foundation Models in computer vision normally require over millions of image-text pairs, while in the medical domain, only a few hundred thousand pairs are available [31]. The limited data challenges language models to understand the reports in free form [6]. Second, the problem considered in computer-aided diagnosis is naturally fine-grained, that requires distinguishing the medical concepts to understand the disease, as a consequence, domain knowledge is essen", + "bbox": [ + 496, + 613, + 893, + 900 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "†: Corresponding author.", + "bbox": [ + 78, + 887, + 212, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "21372", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "tial; Third, robustness is crucial, it is, therefore, preferable to have explainability, where diagnosis results come along with the visual grounding, to help radiologists understand the system, and build trust between human and machines.", + "bbox": [ + 78, + 90, + 467, + 150 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Existing work in medical VLP (Vision-Language Pretraining) [68, 47, 25, 6] follows a straightforward training paradigm by matching raw reports with image scans, as shown in Fig.1A, ignoring the medical prior knowledge, and, thus, we propose a novel knowledge-enhanced visual-language model as shown in Fig. 1B. First, we propose a triplet extraction module to extract useful medical entities (keywords) from raw reports, and simplify each report into sets of triplets, denoted as {entity, position, exist}. Decomposing reports into triplets leads to an effective representation of the reports with minimal information loss due to the structural prior in reports; Second, we translate the medical entities into fine-grained descriptions by leveraging a well-defined medical word knowledge base, that tends to explain diseases with common vocabulary. Thus, computing text embeddings for these descriptions enables to implicitly establish relationships between medical entities; Third, we view the entities as a query set and adopt a transformer-based architecture for aligning the image patches with entity descriptions, that enables explicit supervision signals at entity level. Consequently, we can simultaneously infer the likelihood of certain diseases with the visual evidence in the form of a spatial heatmap, i.e., providing rough grounding for explainability.", + "bbox": [ + 80, + 152, + 467, + 513 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We pre-train the model on one widely-used medical image-report dataset MIMIC-CXR [31], and rigorously evaluate on the task of disease diagnosis across numerous public benchmarks, e.g., ChestX-ray14 [58], RSNA Pneumonia [51], SIIM-ACR Pneumothorax [1], COVIDx CXR2 [48], COVID Rural [54, 15], and EdemaSeverity [7]. We get state-of-the-art performance on zero-shot classification and grounding on different diseases, spanning different image distributions, with further fine-tuning, our model still exceeds previous models significantly.", + "bbox": [ + 80, + 517, + 467, + 667 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 80, + 684, + 215, + 700 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "General Vision-Language Pre-training (VLP) Models. In computer vision, such line of research has gained tremendous success in the recent literature, generally speaking, the developed architectures can either be two-stream [4, 33, 30], i.e., dual encoders, or those based on single-stream methods [35, 9], that favors visual-language fusion. In particular, several works [13, 38, 66] consider considers to combine the commonsense knowledge into the vision-language pre-training, however, in this paper, we focus on medical domain, which is clearly more fine-grained and requires significantly more expertise.", + "bbox": [ + 80, + 710, + 467, + 876 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Medical Named-Entity-Rcognition (NER) Models. Var", + "bbox": [ + 80, + 885, + 467, + 898 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "ious natural language processing (NLP) approaches have been proposed to extract information from radiology reports [49, 28, 44, 52]. These early methods considered only the disease, thus causing information loss. Further state-of-the-art works [29, 61] are proposed to extract relationship between different entities without demand of pre-defined close disease set, retaining most of useful information with high accuracy. In weakly supervision [67] and report generation fields [14], NER methods have shown great impact, and greatly inspired us for more effective vision-language pre-training with medical domain knowledge injected.", + "bbox": [ + 503, + 90, + 888, + 257 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Medical Knowledge Enhanced Models. In general NLP, many works considering combining knowledge, e.g., K-BERT [41] while they consider general knowledge more and focuses on language encoding. In medical community, leveraging external medical knowledge to enhance deep learning models is also a quite important topic [62]. Depending the approaches of using medical knowledge, They can be classified into model-based or input-based. In model-based approaches, the authors aim to imitate the radiological or diagnosis practice to design models [34, 23, 57, 26, 45, 21, 12]. While in input-based approaches, the knowledge is treated as an extra input for computing features [65, 63, 53, 11] or to guide the final training loss [8, 27, 37, 39, 43], commonly used in report generation tasks [59, 64, 40, 11, 36]. However, none of these works are targeting on vision-language pre-training in medical domain with image-report.", + "bbox": [ + 503, + 261, + 888, + 518 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Concurrent Works in Medical VLP. Existing medical VLP methods follow the two-stream flow [68, 25, 7, 47, 60, 10], i.e., use contrastive learning and without fusion module, for example, ConVIRT [68] initially proposed to use contrastive loss as a proxy task for aligning the medical scan and corresponding reports, LoVT and GLoRIA then focus on improving the local alignment performance [25, 7]. BioViL notices the language pattern in reports is different from natural texts and re-designs the language model [6]. The recent arxiv preprint, MedCLIP [60], considers leveraging unpaired data to make up data scarcity. The most related to ours is CheXzero [56], which targets at zero-shot diagnosis. Align [10] focuses on leveraging external medical knowledge to improve the performance of VLP model on medical Visual Question Answering (VQA). However, they treat knowledge as an additional loss and we adopt a new training scheme leveraging medical knowledge by aligning entity, instead of raw reports, with images. Despite significant contribution has been made by existing work [68, 25, 7, 47, 60, 56], they still treat medical texts and images as common natural data and do not explicitly leverage the rich prior knowledge from medical domain. In this paper, we consider to incorporate domain knowledge, re-design the pre-training pipeline delicately and target at accurate diagnosis in X-ray scans.", + "bbox": [ + 503, + 523, + 888, + 898 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "21373", + "bbox": [ + 478, + 925, + 517, + 936 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/184e46e42002293ec887f663549c937d2195280796d5db9df1c9cdf2a9572e59.jpg", + "image_caption": [ + "A. Report Pre-processing" + ], + "image_footnote": [], + "bbox": [ + 81, + 107, + 232, + 233 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/451617ab1cdd63e7cf8934a4a7fac0f453f4ef445779f596a32b658c20aa624b.jpg", + "image_caption": [ + "B. Knowledge-enhanced Triplet Encoding" + ], + "image_footnote": [], + "bbox": [ + 248, + 108, + 496, + 237 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/1e1f7ad98701c856502e4577d8ac37167e88115900b73763bd0763e5e9981816.jpg", + "image_caption": [ + "C. Training Flow", + "Figure 2: The whole framework of our method. We first pre-process the report into triplets leveraging triplet extraction module. Then we encode the extracted triplets and it is worth emphasizing that we translate the entities into detailed descriptions during encoding, by querying the medical knowledge base. Finally we change the training flow with triplets, i.e., we query a transformer-based fusion module at entity level, which provides more detailed supervision signals." + ], + "image_footnote": [], + "bbox": [ + 511, + 107, + 888, + 239 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Method", + "text_level": 1, + "bbox": [ + 76, + 320, + 166, + 335 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this section, we start by describing the considered problem scenario in Sec. 3.1, followed by our report pre-process operation with triplet extraction in Sec. 3.2. Then we introduce our proposed knowledge-enhanced architecture in Sec. 3.3, including, visual encoder, knowledge-enhanced triplet encoder, and the fusion module for aligning visual-language signals. In Sec. 3.4, we describe the training procedure with the paired image-reports sourced from the daily routine X-ray scans and, in Sec.3.5, we introduce the procedure for inference.", + "bbox": [ + 75, + 349, + 468, + 501 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Problem Scenario", + "text_level": 1, + "bbox": [ + 76, + 525, + 250, + 539 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Assuming we are given a training set with $N$ samples, i.e., $\\mathcal{D}_{\\mathrm{train}} = \\{(\\mathcal{X}_1,\\mathcal{T}_1),\\ldots ,(\\mathcal{X}_N,\\mathcal{T}_N)\\}$ , where $\\mathcal{X}_i,\\mathcal{T}_i$ refer to the X-ray image and its corresponding medical report generated in the daily routine scans, respectively, our goal is to train a visual-language model that enables us to diagnose the existence of certain diseases and localize the visual evidence spatially. Specifically, at inference time, we can freely ask the system to identify the likelihood of the patient getting a certain disease (seen or unseen during training):", + "bbox": [ + 75, + 553, + 468, + 705 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {s} _ {i}, \\hat {m} _ {i} = \\Phi_ {\\text {f u s i o n}} \\left(\\Phi_ {\\text {v i s u a l}} \\left(\\mathcal {X} _ {i}\\right), \\Phi_ {\\text {t e x t u a l}} ([ \\text {d e s c r i p t i o n} ])\\right), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 91, + 726, + 468, + 742 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\mathcal{X}_i\\in \\mathbb{R}^{H\\times W\\times 3}$ refers to an image sample from the test set, with $H,W$ denoting height and width respectively. $\\hat{s}_i\\in [0,1]$ refers to the inferred likelihood of the patient having a certain disease indicated by the input description, and $\\hat{m}_i\\in \\mathbb{R}^{H\\times W\\times 1}$ denotes a predicted spatial heatmap, with high activation on pixels that potentially provide the visual indication for such disease. In the following section, we will introduce our report pre-process operation with triplet extraction.", + "bbox": [ + 75, + 763, + 468, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Report Pre-processing", + "text_level": 1, + "bbox": [ + 500, + 321, + 707, + 337 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To start with, we propose to pre-process medical reports with a Triplet Extraction module by removing the unnecessary complexity from language grammar. Note that, we hereon only consider single sampled image-reports pair $(\\mathcal{X}_i,\\mathcal{T}_i)$ , and ignore the subscript in notations for simplicity.", + "bbox": [ + 498, + 344, + 890, + 420 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We condense the original reports with an off-shelf medical Named Entity Recognition (NER) method, namely RadGraph [29, 67], transforming reports into a set of triplets, as shown in Figure 2A. In detail, the medical key words can be extracted and classified as \"entity\" or \"position\" with the NER module. \"Entity\" refers to some clinical observations, like \"Opacity\". \"Position\" refers to the anatomical body part that occurs in a radiology report, like \"right lower lobe\". Besides, the NER module will also provide an \"exist\" label to conclude whether an entity is claimed to be exist, absent or uncertain in reports. Based on this, we can use a set of triplets, i.e., {entity, position, exist}, to reformulate the sentence in reports, for example, the triplet {Opacity, Right lower lobe, True} represents \"It is true that there is opacity located at right lower lobe\". Note that, the triplets with a specific \"position\" are not always termed as True in \"exist\" as radiologists may point out entities absent at some specific position.", + "bbox": [ + 496, + 420, + 892, + 691 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Therefore, given a report $\\mathcal{T}$ with multiple sentences, $\\mathcal{T} = \\{s_1,s_2,\\dots ,s_M\\}$ , the extraction module independently operates on each of the sentences, and construct a number of triplets from the report:", + "bbox": [ + 498, + 691, + 890, + 752 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\Phi_ {\\mathrm {e x}} \\left(s _ {j}\\right) = \\left\\{\\text {e n t i t y} _ {n}, \\text {p o s i t i o n} _ {n}, \\text {e x i s t} _ {n} \\right\\}, n \\in [ 0, t _ {j} ], \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 519, + 763, + 890, + 780 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $t_j$ represents the total number of entities contained in one sentence, with $n = 0$ indicating the special case that there is no valid entity. After the triplet extraction, each report is equal to a set of triplets.", + "bbox": [ + 496, + 790, + 890, + 851 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Discussion. In contrast to natural texts, information in medical reports tends to be more condensed, with radiologists pointing out the existence of abnormality and their positions", + "bbox": [ + 498, + 854, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "21374", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "in the image. Meanwhile, medical terminologies tend to be professional, and within certain vocabulary (mostly listed in UMLS [5]), specially designed NER methods [29] demonstrate great performance on reports. Therefore, adopting the Triplet Extraction operation in medical VLP can avoid unnecessary complexity from understanding grammar, while still retaining the useful information in reports.", + "bbox": [ + 75, + 90, + 472, + 196 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Architecture", + "text_level": 1, + "bbox": [ + 76, + 209, + 210, + 224 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In this section, we detail our proposed framework, consisting of three components, namely, visual encoding, knowledge-enhanced triplet encoding, and fusion module, as shown in Fig. 2B and Fig. 2C.", + "bbox": [ + 75, + 233, + 468, + 294 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3.1 Visual Encoding", + "text_level": 1, + "bbox": [ + 76, + 316, + 246, + 333 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Given an X-ray image scan $\\mathcal{X} \\in \\mathbb{R}^{H \\times W \\times 3}$ , we can compute the features with a visual backbone:", + "bbox": [ + 75, + 342, + 468, + 373 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {V} = \\Phi_ {\\text {v i s u a l}} (\\mathcal {X}) \\in \\mathbb {R} ^ {h \\times w \\times d}, \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 179, + 386, + 468, + 405 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "$h, w, d$ refer to the height, width, and feature dimension of the output, in our case, we adopt ResNet-50 as the visual backbone, and take the output from the 4th residual block. Note that, we make the architectural choice for fair comparison with existing work [68, 47, 25, 6], while other visual backbones, e.g., ViT [17], can equally be applied.", + "bbox": [ + 75, + 417, + 472, + 508 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3.2 Knowledge-enhanced Triplet Encoding", + "text_level": 1, + "bbox": [ + 76, + 532, + 403, + 547 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The goal of this module is to encode the triplets extracted from reports by incorporating medical domain knowledge as shown in Fig.2B.", + "bbox": [ + 75, + 558, + 468, + 603 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Given a triplet as $\\{\\text{entity}, \\text{position}, \\text{exist}\\}$ , it is easy to code the \"exist\" as it only has three outcomes. We use $l \\in \\{0, 1, -1\\}$ tockenize it, 1 for True, 0 for False, -1 for uncertain. For the \"entity\" words, we translate them into detailed descriptions by querying some easy-access medical knowledge bases [12], e.g., Description([“Pneumonia”]) = \"It is a condition of the lung primarily ... present with opacities and pleural effusion ...\". Despite its simplicity, converting the entities into descriptions is crucial for more reliable and zero-shot diagnosis, as it further decomposes the professional medical entities into basic attributes that are shared by different diseases, encouraging the model to capture a deep understanding of the visual evidence. For the \"position\" words, we use a prompt as \"It is located at $\\{\\text{position}\\}$ \" to form a sentence. Finally, we use ClinicalBERT [3] as a pre-trained text encoder, to compute the embedding for the \"entity\" and \"position\", and then adopt a linear MLP to", + "bbox": [ + 75, + 604, + 472, + 863 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "project the embedding to desired dimensions:", + "bbox": [ + 500, + 90, + 802, + 106 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\ne = \\Phi_ {\\text {t e x t u a l}} (\\text {D e s c r i p t i o n} (\\{\\text {e n t i t y} \\})) \\in \\mathbb {R} ^ {d}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 524, + 117, + 890, + 135 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\np = \\Phi_ {\\text {t e x t u a l}} \\left(\" \\text {I t i s l o c a t e d a t} \\{\\text {p o s i t i o n} \\}\\right) \\in \\mathbb {R} ^ {d ^ {\\prime}}. \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 524, + 138, + 890, + 157 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Each triplet has now been embedded into $\\{e,p,l\\}$ .", + "bbox": [ + 500, + 169, + 833, + 185 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Discussion. The extracted entities are medical terminologies that are only understandable to audiences with a medical background, while enriching them with detailed descriptions helps the model to capture a deep understanding of visual evidence for diseases. Such patterns can be generalized across diseases, as many attribute descriptions tend to be shared, enabling the model to build implicit relationships on seen classes and understand descriptions for unseen ones.", + "bbox": [ + 498, + 188, + 890, + 309 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3.3 Fusion Module", + "text_level": 1, + "bbox": [ + 500, + 330, + 660, + 344 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "With the triplets from reports, we can supervise the model on the entity level instead of the entire report level. The \"position\" and \"exist\" parts in triplets can be naturally seen as more fine-grained supervision labels. Specifically, we adopt a Transformer-based architecture, use the embedding of entities as query, iteratively attending the image embeddings, and output exist and position predictions of entities.", + "bbox": [ + 498, + 354, + 890, + 459 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In detail, we select the top $|Q|$ most commonly appearing entities' embeddings in all training reports, to form an entity query set $Q = \\{e_1, e_2, \\dots, e_{|Q|}\\}$ . The details of the entity query set is provided in the supplementary material (Sec. A). Then $Q$ will be passed into a fusion module with the image representation $\\mathcal{V}$ for alignment. The fusion module consists of multiple Transformer Decoder layers, with $Q$ as Query, and $\\mathcal{V}$ as Key and Value. The outputs are further fed into two MLPs, independently infer the existence of the entity and the entity's position:", + "bbox": [ + 498, + 460, + 890, + 611 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\left\\{\\hat {s}, \\hat {p}, \\hat {m} \\right\\} = \\Phi_ {\\text {f u s i o n}} (\\mathcal {V}, Q), \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 599, + 625, + 890, + 642 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\hat{s} \\in \\mathbb{R}^{|Q|}$ represents the existence prediction for each entity query, and $\\hat{p} \\in \\mathbb{R}^{|Q| \\times d'}$ represents the predicted position for all entities. Note that, $\\hat{m} \\in \\mathbb{R}^{H \\times W}$ denotes the average of the cross-attention maps sourced from Transformer layers and is up-sampled to the size of input image with nearest interpolation. $\\hat{m}$ is used for grounding at inference, as it naturally acts as a segmentation heatmap. During training, we will not directly calculate any loss on it.", + "bbox": [ + 496, + 652, + 893, + 776 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Discussion. Adopting Transformer decoder enables to compute correspondences between entities and images at patch-level. Consequently, image features $\\mathcal{V}$ are more suitable for downstream segmentation tasks and the average of cross-attention maps in each layers can be used directly for zero-shot grounding, providing explainable for diagnosis. Besides, the default self-attention on queries in Transformer structure can also build relationships across entities.", + "bbox": [ + 496, + 779, + 893, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_footnote", + "text": "$^{1}$ Wikipedia https://en.wikipedia.org/wiki/ $^{2}$ UMLS [5] https://www.nlm.nih.gov/research/uml5/", + "bbox": [ + 76, + 875, + 442, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "21375", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.4. Training", + "text_level": 1, + "bbox": [ + 76, + 90, + 181, + 107 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Given a set of encoded triplets $\\{e,p,l\\}$ extracted from the pairing reports $\\mathcal{T}$ , we can compute training loss on the output of fusion module. For the existence prediction $\\hat{s}$ , we use binary cross-entropy with the corresponding \"exist\" labels $l$ , and if $l$ is $-1$ we just pass this label, denoted as $\\mathcal{L}_{\\mathrm{cls}}$ . To supervise the position prediction for each entity query, we adopt contrastive learning. We form a position set with top $|P|$ common position embeddings as a position set, $P = \\{p_{1},p_{2},\\dots ,p_{|P|}\\}$ , randomly sample $M$ negative position embeddings from it, and use the corresponding position embedding $p$ from triplets as positive:", + "bbox": [ + 75, + 112, + 472, + 282 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {l o c}} = - \\frac {1}{| Q |} \\sum_ {k = 1} ^ {| Q |} \\frac {e ^ {\\langle \\hat {p} _ {k} , p _ {k} \\rangle}}{e ^ {\\langle \\hat {p} _ {k} , p _ {k} \\rangle} + \\sum_ {u = 1} ^ {M} e ^ {\\langle \\hat {p} _ {k} , P _ {\\mathcal {I} (k , u)} \\rangle}}, \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 101, + 291, + 468, + 335 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\langle \\cdot, \\cdot \\rangle$ represents the inner product of two vectors and $\\mathcal{I}(\\cdot, \\cdot)$ is a random index sampling function. The position embeddings are un-normalized in calculation. Note that, some entities may not be mentioned in the report and thus, we can not find corresponding labels in triplets. We simply ignore the corresponding predictions while computing loss.", + "bbox": [ + 76, + 344, + 468, + 435 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The final loss is the sum of the two:", + "bbox": [ + 96, + 436, + 334, + 450 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {t o t a l}} = \\alpha_ {1} \\mathcal {L} _ {\\text {l o c}} + \\alpha_ {2} \\mathcal {L} _ {\\text {c l s}}, \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 187, + 463, + 468, + 479 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\alpha_{1},\\alpha_{2}$ refer to two hyper-parameters controlling the ratio of the two losses, and we set them to be 1.0 by default.", + "bbox": [ + 76, + 489, + 468, + 521 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Discussion. In contrast to the existing approaches [68] that align images with entire reports, our training paradigm with triplets provides supervision at a more fine-grained entity level, rather than the global alignment between image and reports as has often done in existing approaches.", + "bbox": [ + 76, + 526, + 468, + 603 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.5. Inference", + "text_level": 1, + "bbox": [ + 76, + 612, + 187, + 626 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "At inference time, given a test image, we can directly infer the existence of certain entities/disease, and ground their visual evidence. In particular, for the entities that have appeared in the entity query set $Q$ , we simply adopt the corresponding elements from $Q$ , while for those unseen ones, we replace the entity with a brief description provided by the user, and treat it as an extra query added to entity query set $Q$ , resembling zero-shot inference. The existence output $\\hat{s}$ can be directly applied for classification, the average cross-attention $\\hat{m}$ between the target entity and the visual features are used for grounding.", + "bbox": [ + 75, + 635, + 468, + 801 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiment", + "text_level": 1, + "bbox": [ + 76, + 815, + 202, + 832 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In this section, we start by introducing the dataset used for experiments, e.g., pre-training, and various downstream datasets. Then we describe the implementation details and the considered baselines.", + "bbox": [ + 76, + 839, + 468, + 898 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.1. Pre-training Dataset", + "text_level": 1, + "bbox": [ + 500, + 90, + 692, + 106 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "MIMIC-CXR v2 [31, 22] consists of over 227k studies of paired image-report data, they are sourced from 65,379 patients at different scanning. Each study can have one or two images (different scan views), totaling 377,110 images.", + "bbox": [ + 498, + 112, + 893, + 175 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Datasets for Downstream Tasks", + "text_level": 1, + "bbox": [ + 500, + 181, + 777, + 196 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "ChestX-ray14 [58] contains 112,120 frontal-view X-ray images of 30,805 unique patients, collected from the year of 1992 to 2015 by NIH(National Institutes of Health), with labels of 14 common diseases provided. We split the dataset into $0.8 / 0.1 / 0.1$ for train-valid/test.", + "bbox": [ + 498, + 205, + 892, + 280 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "RSNA Pneumonia [51] contains more than 260k frontal-view chest X-rays with corresponding pneumonia opacity masks collected by RSNA (Radiological Society of North America). Commonly, it is treated as a classification tasks [25, 6]. We split the dataset into $0.6 / 0.2 / 0.2$ for train-valid/test.", + "bbox": [ + 498, + 284, + 893, + 375 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "SIIM-ACR Pneumothorax [1] contains more than 12k frontal-view chest X-rays with pneumothorax masks collected by SIIM-ACR (Society for Imaging Informatics in Medicine and American College of Radiology). Similarly to RSNA Pneumonia dataset, it can be both used as classification and segmentation tasks. We split the dataset into 0.6/0.2/0.2 for train-valid/test.", + "bbox": [ + 498, + 378, + 892, + 484 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "COVIDx CXR-2 [48] and COVID Rural [54, 15] aim to evaluate on diagnosing COVID-19. COVIDx CXR-3 contains 29,986 images from 16,648 patients with COVID-19 classification labels. We use it as a classification dataset and split it into $0.7 / 0.2 / 0.1$ for train-valid/test. Additionally, we use COVID Rural dataset for COVID-19 segmentation. It contains more than 200 chest X-rays with segmentation masks, and we split it into $0.6 / 0.2 / 0.2$ for train-valid/test.", + "bbox": [ + 498, + 487, + 892, + 609 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Edema Severity [7] contains 6,524 examples from MIMIC-CXR with pulmonary edema severity labels (0 to 3, increasing severity) extracted from the radiology reports. Of these, 141 radiologists were examined by radiologists, and consensus was reached on severity level. It can be seen as a typical fine-grained classification task. We split the dataset into $0.6 / 0.2 / 0.2$ for train-valid/test.", + "bbox": [ + 498, + 612, + 893, + 719 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.3. Implementation", + "text_level": 1, + "bbox": [ + 500, + 726, + 660, + 742 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "This section describes the implementation for architectures. In Pre-training, the triplets extraction module and text encoders used in triplets encoding are all fixed, while the visual encoder and fusion module are trained end-to-end on the image-text pairs. In Fine-tuning, we adopt ResNet50 [24] initialized with image encoder for classification, and ResUNet [16] initialize its encoder with our pretrained image encoder for segmentation. More details about exact values of different parameters and training progress can be found in supplementary material (Sec. B)", + "bbox": [ + 498, + 750, + 893, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "21376", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/94e0e3b58e16fc02e2731faa5945743bda758597494b5f18794a11cc6e3dee7e.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Dataset MethodsRSNA PneumoniaSIIM-ACR PneumothoraxChestX-ray14
AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑
ConVIRT [68]0.80420.58420.76110.64310.43290.57000.61010.16280.7102
GLoRIA [25]0.71450.49010.71290.53420.38230.40470.66100.17320.7700
BioViL [6]0.82800.58330.76690.70790.48550.69090.69120.19310.7916
CheXzero [56]0.85790.62110.79420.68790.47040.54660.72960.21410.8278
Ours0.86940.63420.80020.89240.68330.84280.76760.25250.8619
", + "bbox": [ + 117, + 89, + 848, + 193 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/616b8d4a6206eb01043de702736db618cb27831de1ae985d3e9dd83f55443560.jpg", + "table_caption": [ + "Table 1: Comparison with other state-of-the-art methods on zero-shot classification task. AUC, F1 and ACC scores are reported. For ChestX-ray14, the metrics all refer to the macro average on the 14 diseases." + ], + "table_footnote": [], + "table_body": "
Prompt Type MethodsDirect Covid-19Covid-19 Description
AUC↑F1↑ACC↑AUC↑F1↑ACC↑
ConVIRT [68]0.61590.70570.61130.52080.69020.5266
GLoRIA [25]0.63190.69380.57100.66590.70070.6083
BioViL [6]0.61370.69580.54610.53820.69100.5375
CheXzero [56]0.64620.73690.66290.66670.64000.6578
Ours0.65610.70660.59170.73960.76700.7006
", + "bbox": [ + 86, + 241, + 566, + 347 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2: Comparison with other state-of-the-art methods on zero-shot Covid-19 classification task. AUC, F1 and ACC scores are reported. \"Direct Covid-19\" refers to directly use \"Covid-19\" to construct the prompt sentence while \"Covid-19 Description\" refers to replace the name \"Covid-19\" with its description.", + "bbox": [ + 573, + 242, + 890, + 348 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.4. Baselines", + "text_level": 1, + "bbox": [ + 76, + 361, + 184, + 376 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We compare with various existing state-of-the-art medical image-text pre-train methods, namely, ConVIRT [68], GLoRIA [25], BioViL [6] and CheXzero [56]. Since ConVIRT and GLoRIA are pre-trained on an in-house dataset, we re-train their models on MIMIC-CXR dataset for fair comparison. For BioViL, we use the officially released models by the authors. For zero-shot setting, we use the prompt as mentioned by BioViL [6] and compare to the very recent method (CheXzero [56]) that has shown to have better zero-shot diagnosis ability than radiologists. For finetuning, we all use the same setting as described in Sec. 4.3.", + "bbox": [ + 75, + 383, + 470, + 551 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.5. Metrics", + "text_level": 1, + "bbox": [ + 76, + 560, + 173, + 574 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "AUC, F1 and ACC are measured for classification tasks. F1 comprehensively measures the recall and precision of the model, and ACC is the short of Accuracy. The final binary prediction threshold is chosen to maximise the F1 score. The ACC score is also calculated under this threshold.", + "bbox": [ + 75, + 585, + 468, + 662 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Pointing Game is used for evaluating the grounding performance. In specific, we extract the region with max response in the output heat-map, for one instance, if the region hit the ground-truth mask, it is considered a positive prediction, otherwise negative. Finally, accuracy can be calculated as the pointing game score.", + "bbox": [ + 75, + 666, + 468, + 758 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Dice and IOU are commonly used for segmentation tasks. For zero-shot segmentation, we search the segmentation threshold with 0.01 interval for all methods, and report the maximal Dice score for each model.", + "bbox": [ + 75, + 760, + 468, + 821 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Precision and Recall refer to the detection Precision and Recall. For medical, it is important that lesions are detected even without fine segmentation. Additionally, in some hard cases, especially for the zero-shot setting, Dice and IOU may be too strict to reflect the performance differ", + "bbox": [ + 75, + 824, + 468, + 902 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "ence. Precision and recall scores can compensate for these. We choose the IOU threshold as 0.1 to calculate the scores.", + "bbox": [ + 498, + 362, + 890, + 392 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Results", + "text_level": 1, + "bbox": [ + 500, + 409, + 586, + 425 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this section, we will report the experimental results. In general, we split the results into two parts: zero-shot setting and fine-tuning setting. In the zero-shot case (Sec. 5.1), we carry out the ablation study and compare it with the other SOTA image-text pre-train methods. We mainly consider classification and segmentation tasks; in the fine-tuning case (Sec. 5.2), we evaluate the model's transferability by fine-tuning the model with $1\\%$ , $10\\%$ , and $100\\%$ data portion. Additionally, we also add a disease grading downstream task, which can be seen as a fine-grade classification task, showing that our pre-trained model can be transferred to the downstream tasks at ease.", + "bbox": [ + 496, + 435, + 890, + 617 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Zero-shot Evaluation", + "text_level": 1, + "bbox": [ + 500, + 628, + 697, + 643 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this section, we compare our method with other state-of-the-art methods under zero-shot setting, on classification and grounding. Due to the space limitation, we include the entire ablation study in the supplementary material (Sec. C), referring to it for more details and analysis, and all comparisons here are made using our best model with position contrastive loss and entity description encoder.", + "bbox": [ + 496, + 654, + 890, + 760 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1.1 Classification", + "text_level": 1, + "bbox": [ + 500, + 784, + 648, + 797 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Seen Diseases. As shown in Tab. 1, we compare with existing methods on three widely-used datasets, demonstrating consistent performance improvement. Specifically, on pneumonia and pneumothorax datasets, despite the images being collected by different clinics with different diseases, our model improves the AUC score from 0.83 to 0.87 on", + "bbox": [ + 496, + 809, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "21377", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/09923556a4426d48dca8851532d90c4f06edd2580c15686400e5a85b1c718236.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodsPointing Game↑Recall↑Precision↑IoU↑Dice↑
GLoRIA [25]0.76070.83300.16210.21820.3468
BioViL [6]0.83420.85210.50340.30290.4386
Ours0.87210.86610.64200.31720.4649
", + "bbox": [ + 78, + 88, + 514, + 157 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/10ef62940d592a119cbca004fa33d052315954cf23d7514cee5ae7d1e9ff9a5f.jpg", + "table_caption": [ + "(a) Zero-shot grounding on Pneumonia" + ], + "table_footnote": [], + "table_body": "
MethodsPointing Game↑Recall↑Precision↑
GLoRIA [25]0.06510.23770.0585
BioViL [6]0.02520.19630.1429
Ours0.19750.35620.1940
", + "bbox": [ + 542, + 88, + 872, + 157 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/8c63fd1c29b95f4d7a08831c7c6f8ff2acdd1bc3844130aa9a1e4b84d0587edf.jpg", + "table_caption": [ + "(b) Zero-shot grounding on Pneumothorax", + "Table 3: Comparison with other state-of-the-art methods on zero-shot region grounding tasks. (a) shows the results on RSNA Pneumonia dataset. (b) shows the results on SIIM-ACR Pneumothorax dataset. The pneumothorax region tends to be thin and narrow and much more challenging for grounding, we thus only consider pointing game, recall, and precision. Our method can achieve better performance on different metrics, especially on the pointing game score. ConVIRT and CheXzero can not realize this function." + ], + "table_footnote": [], + "table_body": "
Prompt Type MethodsDirect COVID-19Covid-19 Description
Pointing Game↑Recall↑Precision↑IoU↑Dice↑Pointing Game↑AR↑AP↑IoU↑Dice↑
GLoRIA [25]0.03640.29060.10730.06450.11410.27270.28210.13360.05960.1075
BioViL [6]0.40000.25640.27030.11980.19670.18180.23930.16370.08610.1427
Ours0.18180.18800.14970.07470.12890.58180.52140.49590.13730.2278
", + "bbox": [ + 133, + 272, + 834, + 353 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 4: Comparison with other state-of-the-art methods on zero-shot Covid-19 opacity region grounding task. \"Direct COVID-19\" refers to directly use \"Covid-19\" to construct the prompt sentence for entity encoding while \"Covid-19 Description\" refers to replace the name \"Covid-19\" with its description. Our method can achieve better performance on different metrics.", + "bbox": [ + 75, + 357, + 892, + 402 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "RSNA pneumonia dataset and from 0.71 to 0.89 on SIIM-ACR pneumothorax dataset, as shown in Tab. 1. This shows that our method can better deal with the multi-center and multi-disease data distribution in medical. While on ChestX-ray14 dataset, we improve the average AUC scores from 0.69 to 0.77, we refer the reader to supplementary material (Sec. D) for detailed comparison of 14 diseases.", + "bbox": [ + 75, + 429, + 468, + 532 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Unseen Diseases. Here, we are considering a strict setting for openset classification, in particular, we use covid-19 to evaluate the systems. Covid-19 is a new disease that only appeared in 2019, MIMIC-CXR reports collected in the year 2015 do not include any entity of covid-19, thus it requires the system to have the ability to diagnose truly unseen diseases. As shown in Tab. 2, existing approaches that only rely on disease name struggles to make the correct diagnosis. While, our proposed approach, after introducing medical knowledge, i.e., using entity descriptions, can understand the complex medical entity descriptions unseen in the training set, and significantly boost the performance from 0.66 to 0.74 on AUC and from 0.59 to 0.70 on ACC, demonstrating entity translation is vital for unseen diseases.", + "bbox": [ + 75, + 539, + 470, + 750 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.1.2 Grounding", + "text_level": 1, + "bbox": [ + 76, + 770, + 209, + 786 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In addition to the plain diagnosis, explainability can be equally critical in healthcare, improving the reliability and trustiness of the machine learning systems. Here, we consider providing explainability by grounding the abnormality in the prediction and compare against the existing approaches. Similarly, we split the diseases into seen and unseen ones, depending on whether their names have ap", + "bbox": [ + 75, + 794, + 468, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "peared in the medical reports. Specifically, \"Pneumonia\" and \"Pneumothorax\" are treated as seen, and \"Covid-19\" is treated as unseen. Due to the space limitation, we include visualization results in supplementary material (Sec. E).", + "bbox": [ + 496, + 429, + 892, + 491 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Seen Diseases. We show the results for grounding on RSNA Pneumonia opacity and SIIM-ACR Pneumothorax collapse in Tab. 3. As shown in Tab. 3a, our proposed model surpasses existing approaches on all metrics, for example, we improve the pointing game score from 0.83 to 0.87, the detection Recall from 0.85 to 0.87, the detection precision from 0.50 to 0.64, the IOU from 0.30 to 0.32 and the Dice from 0.44 to 0.46. While on SIIM-ACR dataset (Tab. 3b), the pneumothorax region tends to be thin and narrow, localizing it can often be more challenging than that of opacity grounding [6], we thus only consider pointing game, recall, and precision. Similarly, our method can achieve significantly better performance than prior approaches.", + "bbox": [ + 496, + 513, + 892, + 710 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Unseen Diseases. We also conduct the zero-shot grounding experiment on the unseen disease, namely, Covid-19, as shown in Tab. 4. Our model has shown consistent improvements in all metrics, e.g., boosting the pointing game score from 0.40 to 0.58. One observation to be noticed is that, results in Tab. 4 are mostly consistent with those in Tab. 2, i.e., better classification results tend to lead to better grounding. Overall, our model with knowledge-enhanced language encoding has facilitated the visual encoder to learn underlying evidence relating to the diseases, therefore, leading to more interpretable representations than prior approaches.", + "bbox": [ + 496, + 734, + 893, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "21378", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/b158c5d30a1bc042dd8c12c147a9cdde0a3069b441872af7c125740b3c474185.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Dataset Data PortionPneumoniaPneumothoraxCovid-19ChestX-ray14
1%10%100%1%10%100%1%10%100%1%10%100%
Scratch0.71070.81500.86260.43470.61200.65710.78610.91620.95540.60050.73650.7924
ConVIRT [68]0.83980.85620.87610.71340.78260.90040.86750.95410.97260.66150.76580.8128
GLoRIA [25]0.85990.86660.88460.74390.85380.90140.90650.93810.97280.67100.76420.8184
BioViL [6]0.82330.85380.88360.69480.77750.86890.89890.95290.97290.69520.75270.8245
Ours0.87310.87990.89310.85270.90710.91880.92240.96570.97290.77210.78940.8323
", + "bbox": [ + 101, + 89, + 866, + 191 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/f83ccbcef85eb6ab8a72b7bd346defb132755ee0c3fd6e650eec13b45dace0f2.jpg", + "table_caption": [ + "Table 5: Comparison of AUC scores with other state-of-the-art methods on fine-tuning classification task. The macro average of AUC scores on 14 diseases are reported for ChestX-ray14 dataset." + ], + "table_footnote": [], + "table_body": "
Diseases Data PortionPneumoniaPneumothoraxCovid-19
1%10%100%1%10%100%1%10%100%
Scratch0.43470.60470.70680.21330.33230.74470.14810.23670.3228
ConVIRT [68]0.57060.64910.72010.54060.61210.73520.19950.27240.3737
GLoRIA [25]0.65550.69070.73280.56730.57780.76940.18890.28090.3869
BioViL [6]0.68240.70380.72490.62670.69980.78490.21130.32390.4162
Ours0.70640.71620.75790.66590.72100.79370.24450.35390.4399
", + "bbox": [ + 119, + 237, + 848, + 342 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/39e9d20d07831c4ca7986eed2711dfe436a7c0fd5203d9aeb9083dc92a7c3e43.jpg", + "table_caption": [ + "Table 6: Comparison of Dice scores with other state-of-the-art methods on fine-tuning segmentation tasks. Three diseases are reported, and for each disease, three data portions, $1\\%$ , $10\\%$ , $100\\%$ are adopted to show the performance change under different data amounts." + ], + "table_footnote": [], + "table_body": "
Methods0123AVG
AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑
Scratch0.76310.70360.67380.53830.35930.32230.66920.43280.70120.84200.56940.87700.70310.51630.6436
ConVIRT [68]0.84530.77690.77930.60990.39380.46290.72020.48430.64450.90470.61540.88090.77000.56760.6919
GLoRIA [25]0.83040.75770.75200.62080.39910.49220.73390.49580.70370.92460.66670.91020.77740.57980.7145
BioViL [6]0.80340.73780.71480.60350.39120.45700.68600.44970.67770.92290.65000.91600.75400.55720.6914
Ours0.85020.76460.75390.66410.41400.53920.76050.52660.70310.88450.62500.91600.78980.58260.7280
", + "bbox": [ + 81, + 402, + 883, + 508 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 7: Comparison with other state-of-the-art methods on fine-tuning edema severity grading multi-class classification task. AUC score is reported in the Table. \"0,1,2,3\" in the table represents the severity level and final average scores are reported.", + "bbox": [ + 75, + 512, + 890, + 544 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.2. Fine-tuning Evaluation", + "text_level": 1, + "bbox": [ + 76, + 565, + 290, + 580 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this section, we consider the fine-tuning scenario, with the pre-trained model as initialization, and trained end-to-end on the downstream tasks. We test on three different tasks, namely, classification, segmentation, and grading. In classification and segmentation, the test splits and metrics are the same as in the \"zero-shot\" section. Grading is a new task we introduce in fine-tuning setting, which can be seen as a fine-grained classification task.", + "bbox": [ + 75, + 593, + 470, + 713 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.2.1 Classification", + "text_level": 1, + "bbox": [ + 76, + 747, + 223, + 762 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We experiment on four different datasets, using $1\\%$ , $10\\%$ , $100\\%$ of the data for fine-tuning, that is consistent with the existing work [68, 25, 6]. As shown in Tab. 5, our model has demonstrated substantial improvements in the AUC scores over the existing approaches across all datasets, reflecting that our pre-trained representation is of higher quality than existing models. We refer the readers to the supplementary material (Sec. D) for more detailed comparison results.", + "bbox": [ + 75, + 779, + 468, + 900 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.2.2 Segmentation", + "text_level": 1, + "bbox": [ + 500, + 565, + 650, + 580 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In Tab. 6, we conduct fine-tuning experiments on three different diseases for segmentation. We pick $1\\%$ , $10\\%$ , $100\\%$ of the data for fine-tuning. For all three different diseases with different image distributions, our methods surpass the existing state-of-the-art methods by a large margin, especially under the low-data regime.", + "bbox": [ + 496, + 599, + 890, + 691 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.2.3 Grading", + "text_level": 1, + "bbox": [ + 500, + 729, + 614, + 746 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Besides diagnosis, grading the disease severity level also plays an important role. Here, we adopt our pre-trained features and train them for the multi-class classification task, with 0 to 3 representing different severity levels. As shown in Tab. 7, for each level, the AUC, F1, and ACC scores are calculated as one class against all other ones, for example, 0 vs $\\{1,2,3\\}$ . Final macro average scores of four levels are computed. On the majority of severity levels, our method can achieve the best results.", + "bbox": [ + 496, + 763, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "21379", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 90, + 194, + 104 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this paper, we introduce a novel medical knowledge enhanced VLP model. First, we propose a triplet extraction module to extract useful medical-related triplets as more useful supervision signals, simplifying complex raw reports with minimal information loss. Second, we translate the entities in extracted triplets into detailed medical descriptions and embed them with a text encoder enabling the network to understand complex medical expert-level knowledge. Finally, a transformer-based structure is proposed to do local region alignment. In experiments, We evaluate our method on different datasets under various settings. Our method shows strong zero-shot classification and grounding abilities, even facing unseen diseases. Additionally, with finetuning, our method still outperforms state-of-the-art methods significantly, showing the superiority of our method.", + "bbox": [ + 75, + 114, + 472, + 344 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement", + "text_level": 1, + "bbox": [ + 76, + 358, + 236, + 376 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work is supported by the National Key R&D Program of China (No. 2022ZD0160702), STCSM (No. 22511106101, No. 18DZ2270700, No. 21DZ1100100), 111 plan (No. BP0719010), and State Key Laboratory of UHD Video and Audio Production and Presentation.", + "bbox": [ + 76, + 383, + 470, + 460 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 76, + 476, + 174, + 492 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Society for imaging informatics in medicine: Siim-acr pneumothorax segmentation. https://www.kaggle.com/c/siim-acr-pneumothorax-segmentation.2019.", + "[2] Emily Alsentzer, John Murphy, William Boag, Wei-Hung Weng, Di Jin, Tristan Naumann, and Matthew McDermott. Publicly available clinical BERT embeddings. In Proceedings of the 2nd Clinical Natural Language Processing Workshop, pages 72-78, Minneapolis, Minnesota, USA, June 2019. Association for Computational Linguistics.", + "[3] Emily Alsentzer, John R Murphy, Willie Boag, WeiHung Weng, Di Jin, Tristan Naumann, WA Redmond, and Matthew BA McDermott. Publicly available clinical bert embeddings. *NAACL HLT* 2019, page 72, 2019.", + "[4] Federico Bianchi, Giuseppe Attanasio, Raphael Pisoni, Silvia Terragni, Gabriele Sarti, and Sri Lakshmi. Contrastive language-image pre-training for the italian language. arXiv preprint arXiv:2108.08688, 2021.", + "[5] Olivier Bodenreider. The unified medical language system (umlts): integrating biomedical terminology. *Nucleic acids research*, 32(suppl_1):D267–D270, 2004.", + "[6] Benedikt Boecking, Naoto Usuyama, Shruthi Bannur, Daniel C Castro, Anton Schwaighofer, Stephanie Hyland, Maria Wetscherek, Tristan Naumann, Aditya Nori, Javier Alvarez-Valle, et al. Making the most of text semantics to improve biomedical vision-language processing. In European conference on computer vision, pages 1-21, 2022. Official Implementa" + ], + "bbox": [ + 86, + 502, + 470, + 901 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "tion: https://github.com/microsoft/hi-ml/tree/main/hi-ml-multimodal.", + "[7] Geeticka Chauhan, Ruizhi Liao, William Wells, Jacob Andreas, Xin Wang, Seth Berkowitz, Steven Horng, Peter Szolovits, and Polina Golland. Joint modeling of chest radiographs and radiology reports for pulmonary edema assessment. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 529-539. Springer, 2020.", + "[8] Sihong Chen, Jing Qin, Xing Ji, Baiying Lei, Tianfu Wang, Dong Ni, and Jie-Zhi Cheng. Automatic scoring of multiple semantic attributes with multi-task feature leverage: a study on pulmonary nodules in ct images. IEEE transactions on medical imaging, 36(3):802-814, 2016.", + "[9] Yen-Chun Chen, Linjie Li, Licheng Yu, Ahmed El Kholy, Faisal Ahmed, Zhe Gan, Yu Cheng, and Jingjing Liu. Uniter: Universal image-text representation learning. In European conference on computer vision, pages 104-120. Springer, 2020.", + "[10] Zhihong Chen, Guanbin Li, and Xiang Wan. Align, reason and learn: Enhancing medical vision-and-language pretraining with knowledge. In Proceedings of the 30th ACM International Conference on Multimedia, pages 5152-5161, 2022.", + "[11] Zhihong Chen, Yan Song, Tsung-Hui Chang, and Xiang Wan. Generating radiology reports via memory-driven transformer. In Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP), pages 1439-1449, 2020.", + "[12] Hui Cui, Yiyue Xu, Wanlong Li, Linlin Wang, and Henry Duh. Collaborative learning of cross-channel clinical attention for radiotherapy-related esophageal fistula prediction from ct. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 212-220. Springer, 2020.", + "[13] Yuhao Cui, Zhou Yu, Chunqi Wang, Zhongzhou Zhao, Ji Zhang, Meng Wang, and Jun Yu. Rosita: Enhancing vision-and-language semantic alignments via cross-and intra-modal knowledge integration. In Proceedings of the 29th ACM International Conference on Multimedia, pages 797-806, 2021.", + "[14] Jean-Benoit Delbrouck, Pierre Chambon, Christian Bluethgen, Emily Tsai, Omar Almusa, and Curtis P Langlotz. Improving the factual correctness of radiology report generation with semantic rewards. arXiv preprint arXiv:2210.12186, 2022.", + "[15] Shivang Desai, Ahmad Baghal, Thidathip Wongsurawat, Piroon Jenjaroenpun, Thomas Powell, Shaymaa Al-Shukri, Kim Gates, Phillip Farmer, Michael Rutherford, Geri Blake, et al. Chest imaging representing a Covid-19 positive rural us population. Scientific data, 7(1):1-6, 2020.", + "[16] Foivos I Diakogiannis, François Waldner, Peter Caccetta, and Chen Wu. Resunet-a: A deep learning framework for semantic segmentation of remotely sensed data. ISPRS Journal of Photogrammetry and Remote Sensing, 162:94-114, 2020.", + "[17] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner," + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "21380", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2020.", + "[18] Jared A Dunnmon, Alexander J Ratner, Khaled Saab, Nishith Khandwala, Matthew Markert, Hersh Sagreiya, Roger Goldman, Christopher Lee-Messer, Matthew P Lungren, Daniel L Rubin, et al. Cross-modal data programming enables rapid medical machine learning. *Patterns*, 1(2):100019, 2020.", + "[19] Bradley J Erickson, Panagiotis Korfiatis, Zeynettin Akkus, and Timothy L Kline. Machine learning for medical imaging. Radiographics, 37(2):505, 2017.", + "[20] Andre Esteva, Brett Kuprel, Roberto A Novoa, Justin Ko, Susan M Swetter, Helen M Blau, and Sebastian Thrun. Dermatologist-level classification of skin cancer with deep neural networks. nature, 542(7639):115-118, 2017.", + "[21] Leyuan Fang, Chong Wang, Shutao Li, Hossein Rabbani, Xiangdong Chen, and Zhimin Liu. Attention to lesion: Lesion-aware convolutional neural network for retinal optical coherence tomography image classification. IEEE transactions on medical imaging, 38(8):1959-1970, 2019.", + "[22] Ary L Goldberger, Luis AN Amaral, Leon Glass, Jeffrey M Hausdorff, Plamen Ch Ivanov, Roger G Mark, Joseph E Mietus, George B Moody, Chung-Kang Peng, and H Eugene Stanley. Physiobank, physiotoolkit, and physionet: components of a new research resource for complex physiologic signals. circulation, 101(23):e215-e220, 2000.", + "[23] Ivan Gonzalez-Diaz. Dermaknet: Incorporating the knowledge of dermatologists to convolutional neural networks for skin lesion diagnosis. IEEE journal of biomedical and health informatics, 23(2):547-559, 2018.", + "[24] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016.", + "[25] Shih-Cheng Huang, Liyue Shen, Matthew P Lungren, and Serena Yeung. Gloria: A multimodal global-local representation learning framework for label-efficient medical image recognition. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 3942-3951, 2021. Official Implementation: https://github.com/ marshuang80/gloria.", + "[26] Xin Huang, Yu Fang, Mingming Lu, Fengqi Yan, Jun Yang, and Yilu Xu. Dual-ray net: automatic diagnosis of thoracic diseases using frontal and lateral chest x-rays. Journal of Medical Imaging and Health Informatics, 10(2):348-355, 2020.", + "[27] Sarfaraz Hussein, Kunlin Cao, Qi Song, and Ulas Bagci. Risk stratification of lung nodules using 3d cnn-based multitask learning. In International conference on information processing in medical imaging, pages 249-260. Springer, 2017.", + "[28] Jeremy Irvin, Pranav Rajpurkar, Michael Ko, Yifan Yu, Silviana Ciurea-Ilicus, Chris Chute, Henrik Marklund, Behzad Haghgoo, Robyn Ball, Katie Shpanskaya, et al. Chexpert: A large chest radiograph dataset with uncertainty labels and expert comparison. In Proceedings of the AAAI conference on artificial intelligence, volume 33, pages 590-597, 2019." + ], + "bbox": [ + 78, + 90, + 468, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[29] Saahil Jain, Ashwin Agrawal, Adriel Saporta, Steven Truong, Tan Bui, Pierre Chambon, Yuhao Zhang, Matthew P Lungren, Andrew Y Ng, Curtis Langlotz, et al. Radgraph: Extracting clinical entities and relations from radiology reports. In Thirty-fifth Conference on Neural Information Processing Systems Datasets and Benchmarks Track (Round 1), 2021.", + "[30] Chao Jia, Yinfei Yang, Ye Xia, Yi-Ting Chen, Zarana Parekh, Hieu Pham, Quoc Le, Yun-Hsuan Sung, Zhen Li, and Tom Duerig. Scaling up visual and vision-language representation learning with noisy text supervision. In International Conference on Machine Learning, pages 4904-4916. PMLR, 2021.", + "[31] AEWP Johnson, Tom Pollard, Roger Mark, Seth Berkowitz, and Steven Horng. Mimic-cxr database. PhysioNet10, 13026:C2JT1Q, 2019.", + "[32] Junnan Li, Dongxu Li, Caiming Xiong, and Steven Hoi. Blip: Bootstrapping language-image pre-training for unified vision-language understanding and generation. arXiv preprint arXiv:2201.12086, 2022.", + "[33] Junnan Li, Ramprasaath Selvaraju, Akhilesh Gotmare, Shafiq Joty, Caiming Xiong, and Steven Chu Hong Hoi. Align before fuse: Vision and language representation learning with momentum distillation. Advances in neural information processing systems, 34:9694-9705, 2021.", + "[34] Liu Li, Mai Xu, Xiaofei Wang, Lai Jiang, and Hanruo Liu. Attention based glaucoma detection: a large-scale database and cnn model. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 10571-10580, 2019.", + "[35] Liunian Harold Li, Mark Yatskar, Da Yin, Cho-Jui Hsieh, and Kai-Wei Chang. Visualbert: A simple and perform-. mant baseline for vision and language. arXiv preprint arXiv:1908.03557, 2019.", + "[36] Mingjie Li, Wenjia Cai, Karin Verspoor, Shirui Pan, Xiaodan Liang, and Xiaojun Chang. Cross-modal clinical graph transformer for ophthalmic report generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 20656-20665, 2022.", + "[37] Xiaomeng Li, Xiaowei Hu, Lequan Yu, Lei Zhu, Chi-Wing Fu, and Pheng-Ann Heng. Canet: cross-disease attention network for joint diabetic retinopathy and diabetic macular edema grading. IEEE transactions on medical imaging, 39(5):1483-1493, 2019.", + "[38] Xiujun Li, Xi Yin, Chunyuan Li, Pengchuan Zhang, Xiaowei Hu, Lei Zhang, Lijuan Wang, Houdong Hu, Li Dong, Furu Wei, et al. Oscar: Object-semantics aligned pre-training for vision-language tasks. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XXX 16, pages 121-137. Springer, 2020.", + "[39] Qing Liao, Ye Ding, Zoe L Jiang, Xuan Wang, Chunkai Zhang, and Qian Zhang. Multi-task deep convolutional neural network for cancer diagnosis. Neurocomputing, 348:66-73, 2019.", + "[40] Fenglin Liu, Xian Wu, Shen Ge, Wei Fan, and Yuexian Zou. Exploring and distilling posterior and prior knowledge for radiology report generation. In Proceedings of" + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "21381", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "the IEEE/CVF conference on computer vision and pattern recognition, pages 13753-13762, 2021.", + "[41] Weijie Liu, Peng Zhou, Zhe Zhao, Zhiruo Wang, Qi Ju, Haotang Deng, and Ping Wang. K-bert: Enabling language representation with knowledge graph. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 2901-2908, 2020.", + "[42] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In International Conference on Learning Representations, 2018.", + "[43] Gabriel Maicas, Andrew P Bradley, Jacinto C Nascimento, Ian Reid, and Gustavo Carneiro. Training medical image analysis systems like radiologists. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 546-554. Springer, 2018.", + "[44] Matthew BA McDermott, Tzu Ming Harry Hsu, Wei-Hung Weng, Marzyeh Ghassemi, and Peter Szolovits. Chexpert++: Approximating the chexpert labeler for speed, differentiability, and probabilistic output. In Machine Learning for Healthcare Conference, pages 913-927. PMLR, 2020.", + "[45] Masahiro Mitsuhara, Hiroshi Fukui, Yusuke Sakashita, Takanori Ogata, Tsubasa Hirakawa, Takayoshi Yamashita, and Hironobu Fujiyoshi. Embedding human knowledge into deep neural network via attention map. arXiv preprint arXiv:1905.03540, 2019.", + "[46] Yasuhide Miura, Yuhao Zhang, Emily Tsai, Curtis Langlotz, and Dan Jurafsky. Improving factual completeness and consistency of image-to-text radiology report generation. In Proceedings of the 2021 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pages 5288-5304, 2021.", + "[47] Philip Müller, Georgios Kaissis, Congyu Zou, and Daniel Rückert. Joint learning of localized representations from medical images and reports. arXiv preprint arXiv:2112.02889, 2021.", + "[48] Maya Pavlova, Naomi Terhljan, Audrey G Chung, Andy Zhao, Siddharth Surana, Hossein Aboutalebi, Hayden Gunraj, Ali Sabri, Amer Alaref, and Alexander Wong. Covid-net cxr-2: An enhanced deep convolutional neural network design for detection of COVID-19 cases from chest x-ray images. Frontiers in Medicine, 9, 2022.", + "[49] Yifan Peng, Xiaosong Wang, Le Lu, Mohammadhadi Bagheri, Ronald Summers, and Zhiyong Lu. Negbio: a high-performance tool for negation and uncertainty detection in radiology reports. AMIA Summits on Translational Science Proceedings, 2018:188, 2018.", + "[50] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning, pages 8748-8763. PMLR, 2021.", + "[51] George Shih, Carol C Wu, Safwan S Halabi, Marc D Kohli, Luciano M Prevedello, Tessa S Cook, Arjun Sharma, Judith K Amorosa, Veronica Arteaga, Maya Galperin-Aizenberg, et al. Augmenting the national institutes of health chest radiograph dataset with expert annotations of possible pneumonia. Radiology. Artificial intelligence, 1(1), 2019." + ], + "bbox": [ + 78, + 92, + 468, + 898 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[52] Akshay Smit, Saahil Jain, Pranav Rajpurkar, Anuj Pareek, Andrew Y Ng, and Matthew Lungren. Combining automatic labelers and expert annotations for accurate radiology report labeling using bert. In Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP), pages 1500-1519, 2020.", + "[53] Jiaxing Tan, Yumei Huo, Zhengrong Liang, and Lihong Li. Expert knowledge-infused deep learning for automatic lung nodule detection. Journal of X-ray Science and Technology, 27(1):17-35, 2019.", + "[54] Haiming Tang, Nanfei Sun, and Yi Li. Deep learning segmentation model for automated detection of the opacity regions in the chest x-rays of the COVID-19 positive patients and the application for disease severity. medRxiv preprint, 2020.", + "[55] Joseph J Titano, Marcus Badgeley, Javin Schefflein, Margaret Pain, Andres Su, Michael Cai, Nathaniel Swinburne, John Zech, Jun Kim, Joshua Bederson, et al. Automated deep-neural-network surveillance of cranial images for acute neurologic events. Nature medicine, 24(9):1337-1341, 2018.", + "[56] Ekin Tiu, Ellie Talius, Pujan Patel, Curtis P Langlotz, Andrew Y Ng, and Pranav Rajpurkar. Expert-level detection of pathologies from unannotated chest x-ray images via self-supervised learning. Nature Biomedical Engineering, pages 1-8, 2022.", + "[57] Kun Wang, Xiaohong Zhang, Sheng Huang, Feiyu Chen, Xiangbo Zhang, and Luwen Huangfu. Learning to recognize thoracic disease in chest x-rays with knowledge-guided deep zoom neural networks. IEEE Access, 8:159790-159805, 2020.", + "[58] Xiaosong Wang, Yifan Peng, Le Lu, Zhiyong Lu, Mohammadhadi Bagheri, and Ronald M Summers. Chestx-ray8: Hospital-scale chest x-ray database and benchmarks on weakly-supervised classification and localization of common thorax diseases. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2097-2106, 2017.", + "[59] Zhanyu Wang, Mingkang Tang, Lei Wang, Xiu Li, and Luping Zhou. A medical semantic-assisted transformer for radiographic report generation. In Medical Image Computing and Computer Assisted Intervention-MICCAI 2022: 25th International Conference, Singapore, September 18-22, 2022, Proceedings, Part III, pages 655-664. Springer, 2022.", + "[60] Zifeng Wang, Zhenbang Wu, Dinesh Agarwal, and Jimeng Sun. Medclip: Contrastive learning from unpaired medical images and text. arXiv preprint arXiv:2210.10163, 2022.", + "[61] Joy T Wu, Nkechinyere Nneka Agu, Ismini Lourentzou, Arjun Sharma, Joseph Alexander Paguio, Jasper Seth Yao, Edward Christopher Dee, William G Mitchell, Satyananda Kashyap, Andrea Giovannini, et al. Chest imagenome dataset for clinical reasoning. In Thirty-fifth Conference on Neural Information Processing Systems Datasets and Benchmarks Track (Round 2), 2021.", + "[62] Xiaozheng Xie, Jianwei Niu, Xuefeng Liu, Zhengsu Chen, Shaojie Tang, and Shui Yu. A survey on incorporating domain knowledge into deep learning for medical image analysis. Medical Image Analysis, 69:101985, 2021.", + "[63] Yutong Xie, Yong Xia, Jianpeng Zhang, Yang Song, Dagan Feng, Michael Fulham, and Weidong Cai. Knowledge-based" + ], + "bbox": [ + 501, + 92, + 890, + 898 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "21382", + "bbox": [ + 478, + 924, + 519, + 936 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "collaborative deep learning for benign-malignant lung nodule classification on chest ct. IEEE transactions on medical imaging, 38(4):991-1004, 2018.", + "[64] Shuxin Yang, Xian Wu, Shen Ge, S Kevin Zhou, and Li Xiao. Knowledge matters: Chest radiology report generation with general and specific knowledge. Medical Image Analysis, 80:102510, 2022.", + "[65] Wenkai Yang, Juanjuan Zhao, Yan Qiang, Xiaotang Yang, Yunyun Dong, Qianqian Du, Guohua Shi, and Muhammad Bilal Zia. Dscgans: Integrate domain knowledge in training dual-path semi-supervised conditional generative adversarial networks and s3vm for ultrasonography thyroid nodules classification. In International conference on medical image computing and computer-assisted intervention, pages 558-566. Springer, 2019.", + "[66] Fei Yu, Jiji Tang, Weichong Yin, Yu Sun, Hao Tian, Hua Wu, and Haifeng Wang. Ernie-vil: Knowledge enhanced vision-language representations through scene graphs. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 3208-3216, 2021.", + "[67] Ke Yu, Shantanu Ghosh, Zhexiong Liu, Christopher Deible, and Kayhan Batmanghelich. Anatomy-guided weakly-supervised abnormality localization in chest x-rays. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 658-668. Springer, 2022.", + "[68] Yuhao Zhang, Hang Jiang, Yasuhide Miura, Christopher D Manning, and Curtis P Langlotz. Contrastive learning of medical visual representations from paired images and text. In Machine Learning for Healthcare, 2022. Highest Starred Implementation: https://github.com/edreisMD/ConVIRT-pytorch." + ], + "bbox": [ + 78, + 90, + 468, + 541 + ], + "page_idx": 11 + }, + { + "type": "page_number", + "text": "21383", + "bbox": [ + 478, + 924, + 517, + 936 + ], + "page_idx": 11 + } +] \ No newline at end of file diff --git a/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/a294a7d4-55de-429f-8329-44c18b938170_model.json b/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/a294a7d4-55de-429f-8329-44c18b938170_model.json new file mode 100644 index 0000000000000000000000000000000000000000..3b1f73d8b80b3f8e093952a9f27b5aab27d3614c --- /dev/null +++ b/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/a294a7d4-55de-429f-8329-44c18b938170_model.json @@ -0,0 +1,2534 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.185, + 0.131, + 0.787, + 0.177 + ], + "angle": 0, + "content": "MedKLIP: Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis" + }, + { + "type": "text", + "bbox": [ + 0.088, + 0.202, + 0.892, + 0.276 + ], + "angle": 0, + "content": "Chaoyi Wu\\(^{1,2}\\), Xiaoman Zhang\\(^{1,2}\\), Ya Zhang\\(^{1,2}\\), Yanfeng Wang\\(^{1,2,\\dagger}\\), Weidi Xie\\(^{1,2,\\dagger}\\) \n\\(^{1}\\)Cooperative Medianet Innovation Center, Shanghai Jiao Tong University \\(^{2}\\)Shanghai AI Laboratory \\(\\{\\mathrm{wtzxxxxwcy02, xm99sjtu, ya_zhang, wangyanfeng, weidi}\\} \\mathrm{sjtu.edu.cn}\\) https://chaoyi-wu.github.io/MedKLIP/" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.31, + 0.314, + 0.326 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.342, + 0.474, + 0.705 + ], + "angle": 0, + "content": "In this paper, we consider enhancing medical visual-language pre-training (VLP) with domain-specific knowledge, by exploiting the paired image-text reports from the radiological daily practice. In particular, we make the following contributions: First, unlike existing works that directly process the raw reports, we adopt a novel triplet extraction module to extract the medical-related information, avoiding unnecessary complexity from language grammar and enhancing the supervision signals; Second, we propose a novel triplet encoding module with entity translation by querying a knowledge base, to exploit the rich domain knowledge in medical field, and implicitly build relationships between medical entities in the language embedding space; Third, we propose to use a Transformer-based fusion model for spatially aligning the entity description with visual signals at the image patch level, enabling the ability for medical diagnosis; Fourth, we conduct thorough experiments to validate the effectiveness of our architecture, and benchmark on numerous public benchmarks e.g., ChestX-ray14, RSNA Pneumonia, SIIM-ACR Pneumothorax, COVIDx CXR-2, COVID Rural, and EdemaSeverity. In both zero-shot and fine-tuning settings, our model has demonstrated strong performance compared with the former methods on disease classification and grounding." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.732, + 0.21, + 0.748 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.757, + 0.47, + 0.879 + ], + "angle": 0, + "content": "With the rapid development of deep learning, numerous works have been proposed to facilitate computer-aided diagnosis in the medical field [46, 20, 55, 19]. Despite the tremendous progress, these models are normally trained to recognize or segment the structures that fall into a certain closed set of anatomical or disease categories, whenever a new disease comes to be of interest, a costly procedure for data annotation, model re-training are required, fundamen" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.309, + 0.892, + 0.43 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.444, + 0.894, + 0.506 + ], + "angle": 0, + "content": "Figure 1: Our method mainly considers combining medical knowledge with VLP. We propose Triplet Extraction and Entity Translation modules, so that the network can be supervised with detailed entity-level signals." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.52, + 0.893, + 0.612 + ], + "angle": 0, + "content": "tally limiting its practical values. As an alternative, recent research considers to train the model on the corpus, consisting of large amount of multi-modal data, that is generated from daily clinical routine, for instance, the most common example is the dataset of X-ray images with paired radiological reports [18, 28, 31]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.614, + 0.895, + 0.901 + ], + "angle": 0, + "content": "This paper presents our preliminary investigation on vision-language representation learning in the medical domain, with the goal of better zero-shot disease diagnosis (classification) and grounding. Undoubtedly, these tasks have also been widely investigated in the computer vision community, with significant progress made on developing Foundational Models in the past years, for example, CLIP [50], ALBEF [33], BLIP[32], etc. However, to achieve such a goal in the medical domain, different challenges must be resolved, that requires research efforts from the community: First, data availability, training Foundation Models in computer vision normally require over millions of image-text pairs, while in the medical domain, only a few hundred thousand pairs are available [31]. The limited data challenges language models to understand the reports in free form [6]. Second, the problem considered in computer-aided diagnosis is naturally fine-grained, that requires distinguishing the medical concepts to understand the disease, as a consequence, domain knowledge is essen" + }, + { + "type": "page_footnote", + "bbox": [ + 0.079, + 0.888, + 0.214, + 0.9 + ], + "angle": 0, + "content": "†: Corresponding author." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.925, + 0.521, + 0.937 + ], + "angle": 0, + "content": "21372" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.08, + 0.092, + 0.468, + 0.151 + ], + "angle": 0, + "content": "tial; Third, robustness is crucial, it is, therefore, preferable to have explainability, where diagnosis results come along with the visual grounding, to help radiologists understand the system, and build trust between human and machines." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.154, + 0.468, + 0.515 + ], + "angle": 0, + "content": "Existing work in medical VLP (Vision-Language Pretraining) [68, 47, 25, 6] follows a straightforward training paradigm by matching raw reports with image scans, as shown in Fig.1A, ignoring the medical prior knowledge, and, thus, we propose a novel knowledge-enhanced visual-language model as shown in Fig. 1B. First, we propose a triplet extraction module to extract useful medical entities (keywords) from raw reports, and simplify each report into sets of triplets, denoted as {entity, position, exist}. Decomposing reports into triplets leads to an effective representation of the reports with minimal information loss due to the structural prior in reports; Second, we translate the medical entities into fine-grained descriptions by leveraging a well-defined medical word knowledge base, that tends to explain diseases with common vocabulary. Thus, computing text embeddings for these descriptions enables to implicitly establish relationships between medical entities; Third, we view the entities as a query set and adopt a transformer-based architecture for aligning the image patches with entity descriptions, that enables explicit supervision signals at entity level. Consequently, we can simultaneously infer the likelihood of certain diseases with the visual evidence in the form of a spatial heatmap, i.e., providing rough grounding for explainability." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.518, + 0.468, + 0.668 + ], + "angle": 0, + "content": "We pre-train the model on one widely-used medical image-report dataset MIMIC-CXR [31], and rigorously evaluate on the task of disease diagnosis across numerous public benchmarks, e.g., ChestX-ray14 [58], RSNA Pneumonia [51], SIIM-ACR Pneumothorax [1], COVIDx CXR2 [48], COVID Rural [54, 15], and EdemaSeverity [7]. We get state-of-the-art performance on zero-shot classification and grounding on different diseases, spanning different image distributions, with further fine-tuning, our model still exceeds previous models significantly." + }, + { + "type": "title", + "bbox": [ + 0.081, + 0.685, + 0.217, + 0.701 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.712, + 0.468, + 0.877 + ], + "angle": 0, + "content": "General Vision-Language Pre-training (VLP) Models. In computer vision, such line of research has gained tremendous success in the recent literature, generally speaking, the developed architectures can either be two-stream [4, 33, 30], i.e., dual encoders, or those based on single-stream methods [35, 9], that favors visual-language fusion. In particular, several works [13, 38, 66] consider considers to combine the commonsense knowledge into the vision-language pre-training, however, in this paper, we focus on medical domain, which is clearly more fine-grained and requires significantly more expertise." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.886, + 0.468, + 0.9 + ], + "angle": 0, + "content": "Medical Named-Entity-Rcognition (NER) Models. Var" + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.092, + 0.89, + 0.258 + ], + "angle": 0, + "content": "ious natural language processing (NLP) approaches have been proposed to extract information from radiology reports [49, 28, 44, 52]. These early methods considered only the disease, thus causing information loss. Further state-of-the-art works [29, 61] are proposed to extract relationship between different entities without demand of pre-defined close disease set, retaining most of useful information with high accuracy. In weakly supervision [67] and report generation fields [14], NER methods have shown great impact, and greatly inspired us for more effective vision-language pre-training with medical domain knowledge injected." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.262, + 0.89, + 0.519 + ], + "angle": 0, + "content": "Medical Knowledge Enhanced Models. In general NLP, many works considering combining knowledge, e.g., K-BERT [41] while they consider general knowledge more and focuses on language encoding. In medical community, leveraging external medical knowledge to enhance deep learning models is also a quite important topic [62]. Depending the approaches of using medical knowledge, They can be classified into model-based or input-based. In model-based approaches, the authors aim to imitate the radiological or diagnosis practice to design models [34, 23, 57, 26, 45, 21, 12]. While in input-based approaches, the knowledge is treated as an extra input for computing features [65, 63, 53, 11] or to guide the final training loss [8, 27, 37, 39, 43], commonly used in report generation tasks [59, 64, 40, 11, 36]. However, none of these works are targeting on vision-language pre-training in medical domain with image-report." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.524, + 0.89, + 0.9 + ], + "angle": 0, + "content": "Concurrent Works in Medical VLP. Existing medical VLP methods follow the two-stream flow [68, 25, 7, 47, 60, 10], i.e., use contrastive learning and without fusion module, for example, ConVIRT [68] initially proposed to use contrastive loss as a proxy task for aligning the medical scan and corresponding reports, LoVT and GLoRIA then focus on improving the local alignment performance [25, 7]. BioViL notices the language pattern in reports is different from natural texts and re-designs the language model [6]. The recent arxiv preprint, MedCLIP [60], considers leveraging unpaired data to make up data scarcity. The most related to ours is CheXzero [56], which targets at zero-shot diagnosis. Align [10] focuses on leveraging external medical knowledge to improve the performance of VLP model on medical Visual Question Answering (VQA). However, they treat knowledge as an additional loss and we adopt a new training scheme leveraging medical knowledge by aligning entity, instead of raw reports, with images. Despite significant contribution has been made by existing work [68, 25, 7, 47, 60, 56], they still treat medical texts and images as common natural data and do not explicitly leverage the rich prior knowledge from medical domain. In this paper, we consider to incorporate domain knowledge, re-design the pre-training pipeline delicately and target at accurate diagnosis in X-ray scans." + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.926, + 0.518, + 0.937 + ], + "angle": 0, + "content": "21373" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.082, + 0.091, + 0.233, + 0.105 + ], + "angle": 0, + "content": "A. Report Pre-processing" + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.108, + 0.233, + 0.234 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.241, + 0.093, + 0.492, + 0.107 + ], + "angle": 0, + "content": "B. Knowledge-enhanced Triplet Encoding" + }, + { + "type": "image", + "bbox": [ + 0.249, + 0.109, + 0.498, + 0.238 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.512, + 0.093, + 0.611, + 0.107 + ], + "angle": 0, + "content": "C. Training Flow" + }, + { + "type": "image", + "bbox": [ + 0.513, + 0.108, + 0.89, + 0.24 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.253, + 0.894, + 0.314 + ], + "angle": 0, + "content": "Figure 2: The whole framework of our method. We first pre-process the report into triplets leveraging triplet extraction module. Then we encode the extracted triplets and it is worth emphasizing that we translate the entities into detailed descriptions during encoding, by querying the medical knowledge base. Finally we change the training flow with triplets, i.e., we query a transformer-based fusion module at entity level, which provides more detailed supervision signals." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.321, + 0.168, + 0.336 + ], + "angle": 0, + "content": "3. Method" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.351, + 0.47, + 0.502 + ], + "angle": 0, + "content": "In this section, we start by describing the considered problem scenario in Sec. 3.1, followed by our report pre-process operation with triplet extraction in Sec. 3.2. Then we introduce our proposed knowledge-enhanced architecture in Sec. 3.3, including, visual encoder, knowledge-enhanced triplet encoder, and the fusion module for aligning visual-language signals. In Sec. 3.4, we describe the training procedure with the paired image-reports sourced from the daily routine X-ray scans and, in Sec.3.5, we introduce the procedure for inference." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.526, + 0.251, + 0.54 + ], + "angle": 0, + "content": "3.1. Problem Scenario" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.554, + 0.47, + 0.706 + ], + "angle": 0, + "content": "Assuming we are given a training set with \\(N\\) samples, i.e., \\(\\mathcal{D}_{\\mathrm{train}} = \\{(\\mathcal{X}_1,\\mathcal{T}_1),\\ldots ,(\\mathcal{X}_N,\\mathcal{T}_N)\\}\\), where \\(\\mathcal{X}_i,\\mathcal{T}_i\\) refer to the X-ray image and its corresponding medical report generated in the daily routine scans, respectively, our goal is to train a visual-language model that enables us to diagnose the existence of certain diseases and localize the visual evidence spatially. Specifically, at inference time, we can freely ask the system to identify the likelihood of the patient getting a certain disease (seen or unseen during training):" + }, + { + "type": "equation", + "bbox": [ + 0.093, + 0.727, + 0.47, + 0.743 + ], + "angle": 0, + "content": "\\[\n\\hat {s} _ {i}, \\hat {m} _ {i} = \\Phi_ {\\text {f u s i o n}} \\left(\\Phi_ {\\text {v i s u a l}} \\left(\\mathcal {X} _ {i}\\right), \\Phi_ {\\text {t e x t u a l}} ([ \\text {d e s c r i p t i o n} ])\\right), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.764, + 0.47, + 0.901 + ], + "angle": 0, + "content": "where \\(\\mathcal{X}_i\\in \\mathbb{R}^{H\\times W\\times 3}\\) refers to an image sample from the test set, with \\(H,W\\) denoting height and width respectively. \\(\\hat{s}_i\\in [0,1]\\) refers to the inferred likelihood of the patient having a certain disease indicated by the input description, and \\(\\hat{m}_i\\in \\mathbb{R}^{H\\times W\\times 1}\\) denotes a predicted spatial heatmap, with high activation on pixels that potentially provide the visual indication for such disease. In the following section, we will introduce our report pre-process operation with triplet extraction." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.322, + 0.708, + 0.338 + ], + "angle": 0, + "content": "3.2. Report Pre-processing" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.345, + 0.892, + 0.421 + ], + "angle": 0, + "content": "To start with, we propose to pre-process medical reports with a Triplet Extraction module by removing the unnecessary complexity from language grammar. Note that, we hereon only consider single sampled image-reports pair \\((\\mathcal{X}_i,\\mathcal{T}_i)\\), and ignore the subscript in notations for simplicity." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.421, + 0.893, + 0.692 + ], + "angle": 0, + "content": "We condense the original reports with an off-shelf medical Named Entity Recognition (NER) method, namely RadGraph [29, 67], transforming reports into a set of triplets, as shown in Figure 2A. In detail, the medical key words can be extracted and classified as \"entity\" or \"position\" with the NER module. \"Entity\" refers to some clinical observations, like \"Opacity\". \"Position\" refers to the anatomical body part that occurs in a radiology report, like \"right lower lobe\". Besides, the NER module will also provide an \"exist\" label to conclude whether an entity is claimed to be exist, absent or uncertain in reports. Based on this, we can use a set of triplets, i.e., {entity, position, exist}, to reformulate the sentence in reports, for example, the triplet {Opacity, Right lower lobe, True} represents \"It is true that there is opacity located at right lower lobe\". Note that, the triplets with a specific \"position\" are not always termed as True in \"exist\" as radiologists may point out entities absent at some specific position." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.693, + 0.892, + 0.753 + ], + "angle": 0, + "content": "Therefore, given a report \\(\\mathcal{T}\\) with multiple sentences, \\(\\mathcal{T} = \\{s_1,s_2,\\dots ,s_M\\}\\), the extraction module independently operates on each of the sentences, and construct a number of triplets from the report:" + }, + { + "type": "equation", + "bbox": [ + 0.52, + 0.764, + 0.892, + 0.781 + ], + "angle": 0, + "content": "\\[\n\\Phi_ {\\mathrm {e x}} \\left(s _ {j}\\right) = \\left\\{\\text {e n t i t y} _ {n}, \\text {p o s i t i o n} _ {n}, \\text {e x i s t} _ {n} \\right\\}, n \\in [ 0, t _ {j} ], \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.791, + 0.892, + 0.852 + ], + "angle": 0, + "content": "where \\( t_j \\) represents the total number of entities contained in one sentence, with \\( n = 0 \\) indicating the special case that there is no valid entity. After the triplet extraction, each report is equal to a set of triplets." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Discussion. In contrast to natural texts, information in medical reports tends to be more condensed, with radiologists pointing out the existence of abnormality and their positions" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.925, + 0.519, + 0.937 + ], + "angle": 0, + "content": "21374" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.198 + ], + "angle": 0, + "content": "in the image. Meanwhile, medical terminologies tend to be professional, and within certain vocabulary (mostly listed in UMLS [5]), specially designed NER methods [29] demonstrate great performance on reports. Therefore, adopting the Triplet Extraction operation in medical VLP can avoid unnecessary complexity from understanding grammar, while still retaining the useful information in reports." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.21, + 0.212, + 0.225 + ], + "angle": 0, + "content": "3.3. Architecture" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.234, + 0.47, + 0.295 + ], + "angle": 0, + "content": "In this section, we detail our proposed framework, consisting of three components, namely, visual encoding, knowledge-enhanced triplet encoding, and fusion module, as shown in Fig. 2B and Fig. 2C." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.318, + 0.248, + 0.334 + ], + "angle": 0, + "content": "3.3.1 Visual Encoding" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.343, + 0.47, + 0.374 + ], + "angle": 0, + "content": "Given an X-ray image scan \\(\\mathcal{X} \\in \\mathbb{R}^{H \\times W \\times 3}\\), we can compute the features with a visual backbone:" + }, + { + "type": "equation", + "bbox": [ + 0.18, + 0.387, + 0.47, + 0.406 + ], + "angle": 0, + "content": "\\[\n\\mathcal {V} = \\Phi_ {\\text {v i s u a l}} (\\mathcal {X}) \\in \\mathbb {R} ^ {h \\times w \\times d}, \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.418, + 0.473, + 0.51 + ], + "angle": 0, + "content": "\\(h, w, d\\) refer to the height, width, and feature dimension of the output, in our case, we adopt ResNet-50 as the visual backbone, and take the output from the 4th residual block. Note that, we make the architectural choice for fair comparison with existing work [68, 47, 25, 6], while other visual backbones, e.g., ViT [17], can equally be applied." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.533, + 0.405, + 0.549 + ], + "angle": 0, + "content": "3.3.2 Knowledge-enhanced Triplet Encoding" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.559, + 0.47, + 0.604 + ], + "angle": 0, + "content": "The goal of this module is to encode the triplets extracted from reports by incorporating medical domain knowledge as shown in Fig.2B." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.605, + 0.473, + 0.864 + ], + "angle": 0, + "content": "Given a triplet as \\(\\{\\text{entity}, \\text{position}, \\text{exist}\\}\\), it is easy to code the \"exist\" as it only has three outcomes. We use \\(l \\in \\{0, 1, -1\\}\\) tockenize it, 1 for True, 0 for False, -1 for uncertain. For the \"entity\" words, we translate them into detailed descriptions by querying some easy-access medical knowledge bases [12], e.g., Description([“Pneumonia”]) = \"It is a condition of the lung primarily ... present with opacities and pleural effusion ...\". Despite its simplicity, converting the entities into descriptions is crucial for more reliable and zero-shot diagnosis, as it further decomposes the professional medical entities into basic attributes that are shared by different diseases, encouraging the model to capture a deep understanding of the visual evidence. For the \"position\" words, we use a prompt as \"It is located at \\(\\{\\text{position}\\}\\)\" to form a sentence. Finally, we use ClinicalBERT [3] as a pre-trained text encoder, to compute the embedding for the \"entity\" and \"position\", and then adopt a linear MLP to" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.092, + 0.803, + 0.107 + ], + "angle": 0, + "content": "project the embedding to desired dimensions:" + }, + { + "type": "equation", + "bbox": [ + 0.526, + 0.118, + 0.892, + 0.136 + ], + "angle": 0, + "content": "\\[\ne = \\Phi_ {\\text {t e x t u a l}} (\\text {D e s c r i p t i o n} (\\{\\text {e n t i t y} \\})) \\in \\mathbb {R} ^ {d}, \\tag {4}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.526, + 0.14, + 0.892, + 0.158 + ], + "angle": 0, + "content": "\\[\np = \\Phi_ {\\text {t e x t u a l}} \\left(\" \\text {I t i s l o c a t e d a t} \\{\\text {p o s i t i o n} \\}\\right) \\in \\mathbb {R} ^ {d ^ {\\prime}}. \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.17, + 0.834, + 0.186 + ], + "angle": 0, + "content": "Each triplet has now been embedded into \\(\\{e,p,l\\}\\)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.189, + 0.892, + 0.31 + ], + "angle": 0, + "content": "Discussion. The extracted entities are medical terminologies that are only understandable to audiences with a medical background, while enriching them with detailed descriptions helps the model to capture a deep understanding of visual evidence for diseases. Such patterns can be generalized across diseases, as many attribute descriptions tend to be shared, enabling the model to build implicit relationships on seen classes and understand descriptions for unseen ones." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.331, + 0.661, + 0.345 + ], + "angle": 0, + "content": "3.3.3 Fusion Module" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.355, + 0.892, + 0.46 + ], + "angle": 0, + "content": "With the triplets from reports, we can supervise the model on the entity level instead of the entire report level. The \"position\" and \"exist\" parts in triplets can be naturally seen as more fine-grained supervision labels. Specifically, we adopt a Transformer-based architecture, use the embedding of entities as query, iteratively attending the image embeddings, and output exist and position predictions of entities." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.461, + 0.892, + 0.612 + ], + "angle": 0, + "content": "In detail, we select the top \\( |Q| \\) most commonly appearing entities' embeddings in all training reports, to form an entity query set \\( Q = \\{e_1, e_2, \\dots, e_{|Q|}\\} \\). The details of the entity query set is provided in the supplementary material (Sec. A). Then \\( Q \\) will be passed into a fusion module with the image representation \\( \\mathcal{V} \\) for alignment. The fusion module consists of multiple Transformer Decoder layers, with \\( Q \\) as Query, and \\( \\mathcal{V} \\) as Key and Value. The outputs are further fed into two MLPs, independently infer the existence of the entity and the entity's position:" + }, + { + "type": "equation", + "bbox": [ + 0.601, + 0.625, + 0.892, + 0.643 + ], + "angle": 0, + "content": "\\[\n\\left\\{\\hat {s}, \\hat {p}, \\hat {m} \\right\\} = \\Phi_ {\\text {f u s i o n}} (\\mathcal {V}, Q), \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.654, + 0.894, + 0.777 + ], + "angle": 0, + "content": "where \\(\\hat{s} \\in \\mathbb{R}^{|Q|}\\) represents the existence prediction for each entity query, and \\(\\hat{p} \\in \\mathbb{R}^{|Q| \\times d'}\\) represents the predicted position for all entities. Note that, \\(\\hat{m} \\in \\mathbb{R}^{H \\times W}\\) denotes the average of the cross-attention maps sourced from Transformer layers and is up-sampled to the size of input image with nearest interpolation. \\(\\hat{m}\\) is used for grounding at inference, as it naturally acts as a segmentation heatmap. During training, we will not directly calculate any loss on it." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Discussion. Adopting Transformer decoder enables to compute correspondences between entities and images at patch-level. Consequently, image features \\(\\mathcal{V}\\) are more suitable for downstream segmentation tasks and the average of cross-attention maps in each layers can be used directly for zero-shot grounding, providing explainable for diagnosis. Besides, the default self-attention on queries in Transformer structure can also build relationships across entities." + }, + { + "type": "page_footnote", + "bbox": [ + 0.077, + 0.875, + 0.444, + 0.901 + ], + "angle": 0, + "content": "\\(^{1}\\)Wikipedia https://en.wikipedia.org/wiki/ \\(^{2}\\)UMLS [5] https://www.nlm.nih.gov/research/uml5/" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.925, + 0.521, + 0.937 + ], + "angle": 0, + "content": "21375" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.091, + 0.182, + 0.108 + ], + "angle": 0, + "content": "3.4. Training" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.113, + 0.473, + 0.283 + ], + "angle": 0, + "content": "Given a set of encoded triplets \\(\\{e,p,l\\}\\) extracted from the pairing reports \\(\\mathcal{T}\\), we can compute training loss on the output of fusion module. For the existence prediction \\(\\hat{s}\\), we use binary cross-entropy with the corresponding \"exist\" labels \\(l\\), and if \\(l\\) is \\(-1\\) we just pass this label, denoted as \\(\\mathcal{L}_{\\mathrm{cls}}\\). To supervise the position prediction for each entity query, we adopt contrastive learning. We form a position set with top \\(|P|\\) common position embeddings as a position set, \\(P = \\{p_{1},p_{2},\\dots ,p_{|P|}\\}\\), randomly sample \\(M\\) negative position embeddings from it, and use the corresponding position embedding \\(p\\) from triplets as positive:" + }, + { + "type": "equation", + "bbox": [ + 0.102, + 0.292, + 0.47, + 0.337 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {l o c}} = - \\frac {1}{| Q |} \\sum_ {k = 1} ^ {| Q |} \\frac {e ^ {\\langle \\hat {p} _ {k} , p _ {k} \\rangle}}{e ^ {\\langle \\hat {p} _ {k} , p _ {k} \\rangle} + \\sum_ {u = 1} ^ {M} e ^ {\\langle \\hat {p} _ {k} , P _ {\\mathcal {I} (k , u)} \\rangle}}, \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.345, + 0.47, + 0.436 + ], + "angle": 0, + "content": "where \\(\\langle \\cdot, \\cdot \\rangle\\) represents the inner product of two vectors and \\(\\mathcal{I}(\\cdot, \\cdot)\\) is a random index sampling function. The position embeddings are un-normalized in calculation. Note that, some entities may not be mentioned in the report and thus, we can not find corresponding labels in triplets. We simply ignore the corresponding predictions while computing loss." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.437, + 0.336, + 0.451 + ], + "angle": 0, + "content": "The final loss is the sum of the two:" + }, + { + "type": "equation", + "bbox": [ + 0.188, + 0.464, + 0.47, + 0.48 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {t o t a l}} = \\alpha_ {1} \\mathcal {L} _ {\\text {l o c}} + \\alpha_ {2} \\mathcal {L} _ {\\text {c l s}}, \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.491, + 0.47, + 0.522 + ], + "angle": 0, + "content": "where \\(\\alpha_{1},\\alpha_{2}\\) refer to two hyper-parameters controlling the ratio of the two losses, and we set them to be 1.0 by default." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.527, + 0.47, + 0.604 + ], + "angle": 0, + "content": "Discussion. In contrast to the existing approaches [68] that align images with entire reports, our training paradigm with triplets provides supervision at a more fine-grained entity level, rather than the global alignment between image and reports as has often done in existing approaches." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.613, + 0.188, + 0.627 + ], + "angle": 0, + "content": "3.5. Inference" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.636, + 0.47, + 0.803 + ], + "angle": 0, + "content": "At inference time, given a test image, we can directly infer the existence of certain entities/disease, and ground their visual evidence. In particular, for the entities that have appeared in the entity query set \\( Q \\), we simply adopt the corresponding elements from \\( Q \\), while for those unseen ones, we replace the entity with a brief description provided by the user, and treat it as an extra query added to entity query set \\( Q \\), resembling zero-shot inference. The existence output \\( \\hat{s} \\) can be directly applied for classification, the average cross-attention \\( \\hat{m} \\) between the target entity and the visual features are used for grounding." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.816, + 0.203, + 0.833 + ], + "angle": 0, + "content": "4. Experiment" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.84, + 0.47, + 0.9 + ], + "angle": 0, + "content": "In this section, we start by introducing the dataset used for experiments, e.g., pre-training, and various downstream datasets. Then we describe the implementation details and the considered baselines." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.091, + 0.694, + 0.107 + ], + "angle": 0, + "content": "4.1. Pre-training Dataset" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.113, + 0.894, + 0.176 + ], + "angle": 0, + "content": "MIMIC-CXR v2 [31, 22] consists of over 227k studies of paired image-report data, they are sourced from 65,379 patients at different scanning. Each study can have one or two images (different scan views), totaling 377,110 images." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.183, + 0.779, + 0.198 + ], + "angle": 0, + "content": "4.2. Datasets for Downstream Tasks" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.206, + 0.893, + 0.281 + ], + "angle": 0, + "content": "ChestX-ray14 [58] contains 112,120 frontal-view X-ray images of 30,805 unique patients, collected from the year of 1992 to 2015 by NIH(National Institutes of Health), with labels of 14 common diseases provided. We split the dataset into \\(0.8 / 0.1 / 0.1\\) for train-valid/test." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.285, + 0.894, + 0.375 + ], + "angle": 0, + "content": "RSNA Pneumonia [51] contains more than 260k frontal-view chest X-rays with corresponding pneumonia opacity masks collected by RSNA (Radiological Society of North America). Commonly, it is treated as a classification tasks [25, 6]. We split the dataset into \\(0.6 / 0.2 / 0.2\\) for train-valid/test." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.379, + 0.893, + 0.485 + ], + "angle": 0, + "content": "SIIM-ACR Pneumothorax [1] contains more than 12k frontal-view chest X-rays with pneumothorax masks collected by SIIM-ACR (Society for Imaging Informatics in Medicine and American College of Radiology). Similarly to RSNA Pneumonia dataset, it can be both used as classification and segmentation tasks. We split the dataset into 0.6/0.2/0.2 for train-valid/test." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.488, + 0.893, + 0.61 + ], + "angle": 0, + "content": "COVIDx CXR-2 [48] and COVID Rural [54, 15] aim to evaluate on diagnosing COVID-19. COVIDx CXR-3 contains 29,986 images from 16,648 patients with COVID-19 classification labels. We use it as a classification dataset and split it into \\(0.7 / 0.2 / 0.1\\) for train-valid/test. Additionally, we use COVID Rural dataset for COVID-19 segmentation. It contains more than 200 chest X-rays with segmentation masks, and we split it into \\(0.6 / 0.2 / 0.2\\) for train-valid/test." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.613, + 0.894, + 0.72 + ], + "angle": 0, + "content": "Edema Severity [7] contains 6,524 examples from MIMIC-CXR with pulmonary edema severity labels (0 to 3, increasing severity) extracted from the radiology reports. Of these, 141 radiologists were examined by radiologists, and consensus was reached on severity level. It can be seen as a typical fine-grained classification task. We split the dataset into \\(0.6 / 0.2 / 0.2\\) for train-valid/test." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.727, + 0.661, + 0.743 + ], + "angle": 0, + "content": "4.3. Implementation" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.75, + 0.894, + 0.902 + ], + "angle": 0, + "content": "This section describes the implementation for architectures. In Pre-training, the triplets extraction module and text encoders used in triplets encoding are all fixed, while the visual encoder and fusion module are trained end-to-end on the image-text pairs. In Fine-tuning, we adopt ResNet50 [24] initialized with image encoder for classification, and ResUNet [16] initialize its encoder with our pretrained image encoder for segmentation. More details about exact values of different parameters and training progress can be found in supplementary material (Sec. B)" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.925, + 0.521, + 0.937 + ], + "angle": 0, + "content": "21376" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.119, + 0.09, + 0.849, + 0.194 + ], + "angle": 0, + "content": "
Dataset MethodsRSNA PneumoniaSIIM-ACR PneumothoraxChestX-ray14
AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑
ConVIRT [68]0.80420.58420.76110.64310.43290.57000.61010.16280.7102
GLoRIA [25]0.71450.49010.71290.53420.38230.40470.66100.17320.7700
BioViL [6]0.82800.58330.76690.70790.48550.69090.69120.19310.7916
CheXzero [56]0.85790.62110.79420.68790.47040.54660.72960.21410.8278
Ours0.86940.63420.80020.89240.68330.84280.76760.25250.8619
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.197, + 0.895, + 0.228 + ], + "angle": 0, + "content": "Table 1: Comparison with other state-of-the-art methods on zero-shot classification task. AUC, F1 and ACC scores are reported. For ChestX-ray14, the metrics all refer to the macro average on the 14 diseases." + }, + { + "type": "table", + "bbox": [ + 0.088, + 0.242, + 0.568, + 0.348 + ], + "angle": 0, + "content": "
Prompt Type MethodsDirect Covid-19Covid-19 Description
AUC↑F1↑ACC↑AUC↑F1↑ACC↑
ConVIRT [68]0.61590.70570.61130.52080.69020.5266
GLoRIA [25]0.63190.69380.57100.66590.70070.6083
BioViL [6]0.61370.69580.54610.53820.69100.5375
CheXzero [56]0.64620.73690.66290.66670.64000.6578
Ours0.65610.70660.59170.73960.76700.7006
" + }, + { + "type": "table_caption", + "bbox": [ + 0.574, + 0.243, + 0.892, + 0.349 + ], + "angle": 0, + "content": "Table 2: Comparison with other state-of-the-art methods on zero-shot Covid-19 classification task. AUC, F1 and ACC scores are reported. \"Direct Covid-19\" refers to directly use \"Covid-19\" to construct the prompt sentence while \"Covid-19 Description\" refers to replace the name \"Covid-19\" with its description." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.362, + 0.186, + 0.377 + ], + "angle": 0, + "content": "4.4. Baselines" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.385, + 0.471, + 0.552 + ], + "angle": 0, + "content": "We compare with various existing state-of-the-art medical image-text pre-train methods, namely, ConVIRT [68], GLoRIA [25], BioViL [6] and CheXzero [56]. Since ConVIRT and GLoRIA are pre-trained on an in-house dataset, we re-train their models on MIMIC-CXR dataset for fair comparison. For BioViL, we use the officially released models by the authors. For zero-shot setting, we use the prompt as mentioned by BioViL [6] and compare to the very recent method (CheXzero [56]) that has shown to have better zero-shot diagnosis ability than radiologists. For finetuning, we all use the same setting as described in Sec. 4.3." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.561, + 0.174, + 0.575 + ], + "angle": 0, + "content": "4.5. Metrics" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.587, + 0.47, + 0.663 + ], + "angle": 0, + "content": "AUC, F1 and ACC are measured for classification tasks. F1 comprehensively measures the recall and precision of the model, and ACC is the short of Accuracy. The final binary prediction threshold is chosen to maximise the F1 score. The ACC score is also calculated under this threshold." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.667, + 0.47, + 0.759 + ], + "angle": 0, + "content": "Pointing Game is used for evaluating the grounding performance. In specific, we extract the region with max response in the output heat-map, for one instance, if the region hit the ground-truth mask, it is considered a positive prediction, otherwise negative. Finally, accuracy can be calculated as the pointing game score." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.761, + 0.469, + 0.822 + ], + "angle": 0, + "content": "Dice and IOU are commonly used for segmentation tasks. For zero-shot segmentation, we search the segmentation threshold with 0.01 interval for all methods, and report the maximal Dice score for each model." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Precision and Recall refer to the detection Precision and Recall. For medical, it is important that lesions are detected even without fine segmentation. Additionally, in some hard cases, especially for the zero-shot setting, Dice and IOU may be too strict to reflect the performance differ" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.363, + 0.892, + 0.393 + ], + "angle": 0, + "content": "ence. Precision and recall scores can compensate for these. We choose the IOU threshold as 0.1 to calculate the scores." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.41, + 0.587, + 0.426 + ], + "angle": 0, + "content": "5. Results" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.436, + 0.892, + 0.618 + ], + "angle": 0, + "content": "In this section, we will report the experimental results. In general, we split the results into two parts: zero-shot setting and fine-tuning setting. In the zero-shot case (Sec. 5.1), we carry out the ablation study and compare it with the other SOTA image-text pre-train methods. We mainly consider classification and segmentation tasks; in the fine-tuning case (Sec. 5.2), we evaluate the model's transferability by fine-tuning the model with \\(1\\%\\), \\(10\\%\\), and \\(100\\%\\) data portion. Additionally, we also add a disease grading downstream task, which can be seen as a fine-grade classification task, showing that our pre-trained model can be transferred to the downstream tasks at ease." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.63, + 0.699, + 0.645 + ], + "angle": 0, + "content": "5.1. Zero-shot Evaluation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.655, + 0.892, + 0.761 + ], + "angle": 0, + "content": "In this section, we compare our method with other state-of-the-art methods under zero-shot setting, on classification and grounding. Due to the space limitation, we include the entire ablation study in the supplementary material (Sec. C), referring to it for more details and analysis, and all comparisons here are made using our best model with position contrastive loss and entity description encoder." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.785, + 0.649, + 0.799 + ], + "angle": 0, + "content": "5.1.1 Classification" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Seen Diseases. As shown in Tab. 1, we compare with existing methods on three widely-used datasets, demonstrating consistent performance improvement. Specifically, on pneumonia and pneumothorax datasets, despite the images being collected by different clinics with different diseases, our model improves the AUC score from 0.83 to 0.87 on" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.925, + 0.521, + 0.937 + ], + "angle": 0, + "content": "21377" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.08, + 0.089, + 0.516, + 0.158 + ], + "angle": 0, + "content": "
MethodsPointing Game↑Recall↑Precision↑IoU↑Dice↑
GLoRIA [25]0.76070.83300.16210.21820.3468
BioViL [6]0.83420.85210.50340.30290.4386
Ours0.87210.86610.64200.31720.4649
" + }, + { + "type": "table_caption", + "bbox": [ + 0.195, + 0.164, + 0.429, + 0.178 + ], + "angle": 0, + "content": "(a) Zero-shot grounding on Pneumonia" + }, + { + "type": "table", + "bbox": [ + 0.543, + 0.089, + 0.874, + 0.158 + ], + "angle": 0, + "content": "
MethodsPointing Game↑Recall↑Precision↑
GLoRIA [25]0.06510.23770.0585
BioViL [6]0.02520.19630.1429
Ours0.19750.35620.1940
" + }, + { + "type": "table_caption", + "bbox": [ + 0.588, + 0.164, + 0.842, + 0.178 + ], + "angle": 0, + "content": "(b) Zero-shot grounding on Pneumothorax" + }, + { + "type": "table_caption", + "bbox": [ + 0.075, + 0.183, + 0.894, + 0.258 + ], + "angle": 0, + "content": "Table 3: Comparison with other state-of-the-art methods on zero-shot region grounding tasks. (a) shows the results on RSNA Pneumonia dataset. (b) shows the results on SIIM-ACR Pneumothorax dataset. The pneumothorax region tends to be thin and narrow and much more challenging for grounding, we thus only consider pointing game, recall, and precision. Our method can achieve better performance on different metrics, especially on the pointing game score. ConVIRT and CheXzero can not realize this function." + }, + { + "type": "table", + "bbox": [ + 0.134, + 0.273, + 0.835, + 0.354 + ], + "angle": 0, + "content": "
Prompt Type MethodsDirect COVID-19Covid-19 Description
Pointing Game↑Recall↑Precision↑IoU↑Dice↑Pointing Game↑AR↑AP↑IoU↑Dice↑
GLoRIA [25]0.03640.29060.10730.06450.11410.27270.28210.13360.05960.1075
BioViL [6]0.40000.25640.27030.11980.19670.18180.23930.16370.08610.1427
Ours0.18180.18800.14970.07470.12890.58180.52140.49590.13730.2278
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.358, + 0.893, + 0.403 + ], + "angle": 0, + "content": "Table 4: Comparison with other state-of-the-art methods on zero-shot Covid-19 opacity region grounding task. \"Direct COVID-19\" refers to directly use \"Covid-19\" to construct the prompt sentence for entity encoding while \"Covid-19 Description\" refers to replace the name \"Covid-19\" with its description. Our method can achieve better performance on different metrics." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.43, + 0.47, + 0.534 + ], + "angle": 0, + "content": "RSNA pneumonia dataset and from 0.71 to 0.89 on SIIM-ACR pneumothorax dataset, as shown in Tab. 1. This shows that our method can better deal with the multi-center and multi-disease data distribution in medical. While on ChestX-ray14 dataset, we improve the average AUC scores from 0.69 to 0.77, we refer the reader to supplementary material (Sec. D) for detailed comparison of 14 diseases." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.54, + 0.471, + 0.751 + ], + "angle": 0, + "content": "Unseen Diseases. Here, we are considering a strict setting for openset classification, in particular, we use covid-19 to evaluate the systems. Covid-19 is a new disease that only appeared in 2019, MIMIC-CXR reports collected in the year 2015 do not include any entity of covid-19, thus it requires the system to have the ability to diagnose truly unseen diseases. As shown in Tab. 2, existing approaches that only rely on disease name struggles to make the correct diagnosis. While, our proposed approach, after introducing medical knowledge, i.e., using entity descriptions, can understand the complex medical entity descriptions unseen in the training set, and significantly boost the performance from 0.66 to 0.74 on AUC and from 0.59 to 0.70 on ACC, demonstrating entity translation is vital for unseen diseases." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.771, + 0.21, + 0.787 + ], + "angle": 0, + "content": "5.1.2 Grounding" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.47, + 0.903 + ], + "angle": 0, + "content": "In addition to the plain diagnosis, explainability can be equally critical in healthcare, improving the reliability and trustiness of the machine learning systems. Here, we consider providing explainability by grounding the abnormality in the prediction and compare against the existing approaches. Similarly, we split the diseases into seen and unseen ones, depending on whether their names have ap" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.43, + 0.893, + 0.492 + ], + "angle": 0, + "content": "peared in the medical reports. Specifically, \"Pneumonia\" and \"Pneumothorax\" are treated as seen, and \"Covid-19\" is treated as unseen. Due to the space limitation, we include visualization results in supplementary material (Sec. E)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.515, + 0.893, + 0.712 + ], + "angle": 0, + "content": "Seen Diseases. We show the results for grounding on RSNA Pneumonia opacity and SIIM-ACR Pneumothorax collapse in Tab. 3. As shown in Tab. 3a, our proposed model surpasses existing approaches on all metrics, for example, we improve the pointing game score from 0.83 to 0.87, the detection Recall from 0.85 to 0.87, the detection precision from 0.50 to 0.64, the IOU from 0.30 to 0.32 and the Dice from 0.44 to 0.46. While on SIIM-ACR dataset (Tab. 3b), the pneumothorax region tends to be thin and narrow, localizing it can often be more challenging than that of opacity grounding [6], we thus only consider pointing game, recall, and precision. Similarly, our method can achieve significantly better performance than prior approaches." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Unseen Diseases. We also conduct the zero-shot grounding experiment on the unseen disease, namely, Covid-19, as shown in Tab. 4. Our model has shown consistent improvements in all metrics, e.g., boosting the pointing game score from 0.40 to 0.58. One observation to be noticed is that, results in Tab. 4 are mostly consistent with those in Tab. 2, i.e., better classification results tend to lead to better grounding. Overall, our model with knowledge-enhanced language encoding has facilitated the visual encoder to learn underlying evidence relating to the diseases, therefore, leading to more interpretable representations than prior approaches." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.925, + 0.521, + 0.937 + ], + "angle": 0, + "content": "21378" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.102, + 0.09, + 0.867, + 0.193 + ], + "angle": 0, + "content": "
Dataset Data PortionPneumoniaPneumothoraxCovid-19ChestX-ray14
1%10%100%1%10%100%1%10%100%1%10%100%
Scratch0.71070.81500.86260.43470.61200.65710.78610.91620.95540.60050.73650.7924
ConVIRT [68]0.83980.85620.87610.71340.78260.90040.86750.95410.97260.66150.76580.8128
GLoRIA [25]0.85990.86660.88460.74390.85380.90140.90650.93810.97280.67100.76420.8184
BioViL [6]0.82330.85380.88360.69480.77750.86890.89890.95290.97290.69520.75270.8245
Ours0.87310.87990.89310.85270.90710.91880.92240.96570.97290.77210.78940.8323
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.197, + 0.895, + 0.228 + ], + "angle": 0, + "content": "Table 5: Comparison of AUC scores with other state-of-the-art methods on fine-tuning classification task. The macro average of AUC scores on 14 diseases are reported for ChestX-ray14 dataset." + }, + { + "type": "table", + "bbox": [ + 0.12, + 0.238, + 0.849, + 0.343 + ], + "angle": 0, + "content": "
Diseases Data PortionPneumoniaPneumothoraxCovid-19
1%10%100%1%10%100%1%10%100%
Scratch0.43470.60470.70680.21330.33230.74470.14810.23670.3228
ConVIRT [68]0.57060.64910.72010.54060.61210.73520.19950.27240.3737
GLoRIA [25]0.65550.69070.73280.56730.57780.76940.18890.28090.3869
BioViL [6]0.68240.70380.72490.62670.69980.78490.21130.32390.4162
Ours0.70640.71620.75790.66590.72100.79370.24450.35390.4399
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.346, + 0.895, + 0.392 + ], + "angle": 0, + "content": "Table 6: Comparison of Dice scores with other state-of-the-art methods on fine-tuning segmentation tasks. Three diseases are reported, and for each disease, three data portions, \\(1\\%\\), \\(10\\%\\), \\(100\\%\\) are adopted to show the performance change under different data amounts." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.403, + 0.885, + 0.51 + ], + "angle": 0, + "content": "
Methods0123AVG
AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑
Scratch0.76310.70360.67380.53830.35930.32230.66920.43280.70120.84200.56940.87700.70310.51630.6436
ConVIRT [68]0.84530.77690.77930.60990.39380.46290.72020.48430.64450.90470.61540.88090.77000.56760.6919
GLoRIA [25]0.83040.75770.75200.62080.39910.49220.73390.49580.70370.92460.66670.91020.77740.57980.7145
BioViL [6]0.80340.73780.71480.60350.39120.45700.68600.44970.67770.92290.65000.91600.75400.55720.6914
Ours0.85020.76460.75390.66410.41400.53920.76050.52660.70310.88450.62500.91600.78980.58260.7280
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.513, + 0.892, + 0.545 + ], + "angle": 0, + "content": "Table 7: Comparison with other state-of-the-art methods on fine-tuning edema severity grading multi-class classification task. AUC score is reported in the Table. \"0,1,2,3\" in the table represents the severity level and final average scores are reported." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.566, + 0.292, + 0.581 + ], + "angle": 0, + "content": "5.2. Fine-tuning Evaluation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.594, + 0.471, + 0.714 + ], + "angle": 0, + "content": "In this section, we consider the fine-tuning scenario, with the pre-trained model as initialization, and trained end-to-end on the downstream tasks. We test on three different tasks, namely, classification, segmentation, and grading. In classification and segmentation, the test splits and metrics are the same as in the \"zero-shot\" section. Grading is a new task we introduce in fine-tuning setting, which can be seen as a fine-grained classification task." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.748, + 0.225, + 0.763 + ], + "angle": 0, + "content": "5.2.1 Classification" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.47, + 0.901 + ], + "angle": 0, + "content": "We experiment on four different datasets, using \\(1\\%\\), \\(10\\%\\), \\(100\\%\\) of the data for fine-tuning, that is consistent with the existing work [68, 25, 6]. As shown in Tab. 5, our model has demonstrated substantial improvements in the AUC scores over the existing approaches across all datasets, reflecting that our pre-trained representation is of higher quality than existing models. We refer the readers to the supplementary material (Sec. D) for more detailed comparison results." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.566, + 0.651, + 0.581 + ], + "angle": 0, + "content": "5.2.2 Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.6, + 0.892, + 0.692 + ], + "angle": 0, + "content": "In Tab. 6, we conduct fine-tuning experiments on three different diseases for segmentation. We pick \\(1\\%\\), \\(10\\%\\), \\(100\\%\\) of the data for fine-tuning. For all three different diseases with different image distributions, our methods surpass the existing state-of-the-art methods by a large margin, especially under the low-data regime." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.731, + 0.615, + 0.747 + ], + "angle": 0, + "content": "5.2.3 Grading" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Besides diagnosis, grading the disease severity level also plays an important role. Here, we adopt our pre-trained features and train them for the multi-class classification task, with 0 to 3 representing different severity levels. As shown in Tab. 7, for each level, the AUC, F1, and ACC scores are calculated as one class against all other ones, for example, 0 vs \\(\\{1,2,3\\}\\). Final macro average scores of four levels are computed. On the majority of severity levels, our method can achieve the best results." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.925, + 0.521, + 0.937 + ], + "angle": 0, + "content": "21379" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.091, + 0.196, + 0.106 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.116, + 0.473, + 0.345 + ], + "angle": 0, + "content": "In this paper, we introduce a novel medical knowledge enhanced VLP model. First, we propose a triplet extraction module to extract useful medical-related triplets as more useful supervision signals, simplifying complex raw reports with minimal information loss. Second, we translate the entities in extracted triplets into detailed medical descriptions and embed them with a text encoder enabling the network to understand complex medical expert-level knowledge. Finally, a transformer-based structure is proposed to do local region alignment. In experiments, We evaluate our method on different datasets under various settings. Our method shows strong zero-shot classification and grounding abilities, even facing unseen diseases. Additionally, with finetuning, our method still outperforms state-of-the-art methods significantly, showing the superiority of our method." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.359, + 0.238, + 0.377 + ], + "angle": 0, + "content": "Acknowledgement" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.385, + 0.472, + 0.462 + ], + "angle": 0, + "content": "This work is supported by the National Key R&D Program of China (No. 2022ZD0160702), STCSM (No. 22511106101, No. 18DZ2270700, No. 21DZ1100100), 111 plan (No. BP0719010), and State Key Laboratory of UHD Video and Audio Production and Presentation." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.477, + 0.175, + 0.493 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.503, + 0.469, + 0.557 + ], + "angle": 0, + "content": "[1] Society for imaging informatics in medicine: Siim-acr pneumothorax segmentation. https://www.kaggle.com/c/siim-acr-pneumothorax-segmentation.2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.56, + 0.47, + 0.644 + ], + "angle": 0, + "content": "[2] Emily Alsentzer, John Murphy, William Boag, Wei-Hung Weng, Di Jin, Tristan Naumann, and Matthew McDermott. Publicly available clinical BERT embeddings. In Proceedings of the 2nd Clinical Natural Language Processing Workshop, pages 72-78, Minneapolis, Minnesota, USA, June 2019. Association for Computational Linguistics." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.645, + 0.47, + 0.701 + ], + "angle": 0, + "content": "[3] Emily Alsentzer, John R Murphy, Willie Boag, WeiHung Weng, Di Jin, Tristan Naumann, WA Redmond, and Matthew BA McDermott. Publicly available clinical bert embeddings. *NAACL HLT* 2019, page 72, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.703, + 0.47, + 0.758 + ], + "angle": 0, + "content": "[4] Federico Bianchi, Giuseppe Attanasio, Raphael Pisoni, Silvia Terragni, Gabriele Sarti, and Sri Lakshmi. Contrastive language-image pre-training for the italian language. arXiv preprint arXiv:2108.08688, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.76, + 0.47, + 0.802 + ], + "angle": 0, + "content": "[5] Olivier Bodenreider. The unified medical language system (umlts): integrating biomedical terminology. *Nucleic acids research*, 32(suppl_1):D267–D270, 2004." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.804, + 0.471, + 0.902 + ], + "angle": 0, + "content": "[6] Benedikt Boecking, Naoto Usuyama, Shruthi Bannur, Daniel C Castro, Anton Schwaighofer, Stephanie Hyland, Maria Wetscherek, Tristan Naumann, Aditya Nori, Javier Alvarez-Valle, et al. Making the most of text semantics to improve biomedical vision-language processing. In European conference on computer vision, pages 1-21, 2022. Official Implementa" + }, + { + "type": "list", + "bbox": [ + 0.087, + 0.503, + 0.471, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "tion: https://github.com/microsoft/hi-ml/tree/main/hi-ml-multimodal." + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.122, + 0.894, + 0.219 + ], + "angle": 0, + "content": "[7] Geeticka Chauhan, Ruizhi Liao, William Wells, Jacob Andreas, Xin Wang, Seth Berkowitz, Steven Horng, Peter Szolovits, and Polina Golland. Joint modeling of chest radiographs and radiology reports for pulmonary edema assessment. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 529-539. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.221, + 0.892, + 0.29 + ], + "angle": 0, + "content": "[8] Sihong Chen, Jing Qin, Xing Ji, Baiying Lei, Tianfu Wang, Dong Ni, and Jie-Zhi Cheng. Automatic scoring of multiple semantic attributes with multi-task feature leverage: a study on pulmonary nodules in ct images. IEEE transactions on medical imaging, 36(3):802-814, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.291, + 0.892, + 0.36 + ], + "angle": 0, + "content": "[9] Yen-Chun Chen, Linjie Li, Licheng Yu, Ahmed El Kholy, Faisal Ahmed, Zhe Gan, Yu Cheng, and Jingjing Liu. Uniter: Universal image-text representation learning. In European conference on computer vision, pages 104-120. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.362, + 0.892, + 0.431 + ], + "angle": 0, + "content": "[10] Zhihong Chen, Guanbin Li, and Xiang Wan. Align, reason and learn: Enhancing medical vision-and-language pretraining with knowledge. In Proceedings of the 30th ACM International Conference on Multimedia, pages 5152-5161, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.433, + 0.892, + 0.502 + ], + "angle": 0, + "content": "[11] Zhihong Chen, Yan Song, Tsung-Hui Chang, and Xiang Wan. Generating radiology reports via memory-driven transformer. In Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP), pages 1439-1449, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.504, + 0.892, + 0.588 + ], + "angle": 0, + "content": "[12] Hui Cui, Yiyue Xu, Wanlong Li, Linlin Wang, and Henry Duh. Collaborative learning of cross-channel clinical attention for radiotherapy-related esophageal fistula prediction from ct. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 212-220. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.589, + 0.892, + 0.671 + ], + "angle": 0, + "content": "[13] Yuhao Cui, Zhou Yu, Chunqi Wang, Zhongzhou Zhao, Ji Zhang, Meng Wang, and Jun Yu. Rosita: Enhancing vision-and-language semantic alignments via cross-and intra-modal knowledge integration. In Proceedings of the 29th ACM International Conference on Multimedia, pages 797-806, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.673, + 0.892, + 0.743 + ], + "angle": 0, + "content": "[14] Jean-Benoit Delbrouck, Pierre Chambon, Christian Bluethgen, Emily Tsai, Omar Almusa, and Curtis P Langlotz. Improving the factual correctness of radiology report generation with semantic rewards. arXiv preprint arXiv:2210.12186, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.745, + 0.892, + 0.814 + ], + "angle": 0, + "content": "[15] Shivang Desai, Ahmad Baghal, Thidathip Wongsurawat, Piroon Jenjaroenpun, Thomas Powell, Shaymaa Al-Shukri, Kim Gates, Phillip Farmer, Michael Rutherford, Geri Blake, et al. Chest imaging representing a Covid-19 positive rural us population. Scientific data, 7(1):1-6, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.816, + 0.892, + 0.872 + ], + "angle": 0, + "content": "[16] Foivos I Diakogiannis, François Waldner, Peter Caccetta, and Chen Wu. Resunet-a: A deep learning framework for semantic segmentation of remotely sensed data. ISPRS Journal of Photogrammetry and Remote Sensing, 162:94-114, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.873, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[17] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner," + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.925, + 0.521, + 0.937 + ], + "angle": 0, + "content": "21380" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.149, + 0.47, + 0.217 + ], + "angle": 0, + "content": "[18] Jared A Dunnmon, Alexander J Ratner, Khaled Saab, Nishith Khandwala, Matthew Markert, Hersh Sagreiya, Roger Goldman, Christopher Lee-Messer, Matthew P Lungren, Daniel L Rubin, et al. Cross-modal data programming enables rapid medical machine learning. *Patterns*, 1(2):100019, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.219, + 0.468, + 0.259 + ], + "angle": 0, + "content": "[19] Bradley J Erickson, Panagiotis Korfiatis, Zeynettin Akkus, and Timothy L Kline. Machine learning for medical imaging. Radiographics, 37(2):505, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.261, + 0.468, + 0.315 + ], + "angle": 0, + "content": "[20] Andre Esteva, Brett Kuprel, Roberto A Novoa, Justin Ko, Susan M Swetter, Helen M Blau, and Sebastian Thrun. Dermatologist-level classification of skin cancer with deep neural networks. nature, 542(7639):115-118, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.317, + 0.468, + 0.384 + ], + "angle": 0, + "content": "[21] Leyuan Fang, Chong Wang, Shutao Li, Hossein Rabbani, Xiangdong Chen, and Zhimin Liu. Attention to lesion: Lesion-aware convolutional neural network for retinal optical coherence tomography image classification. IEEE transactions on medical imaging, 38(8):1959-1970, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.386, + 0.468, + 0.468 + ], + "angle": 0, + "content": "[22] Ary L Goldberger, Luis AN Amaral, Leon Glass, Jeffrey M Hausdorff, Plamen Ch Ivanov, Roger G Mark, Joseph E Mietus, George B Moody, Chung-Kang Peng, and H Eugene Stanley. Physiobank, physiotoolkit, and physionet: components of a new research resource for complex physiologic signals. circulation, 101(23):e215-e220, 2000." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.47, + 0.468, + 0.524 + ], + "angle": 0, + "content": "[23] Ivan Gonzalez-Diaz. Dermaknet: Incorporating the knowledge of dermatologists to convolutional neural networks for skin lesion diagnosis. IEEE journal of biomedical and health informatics, 23(2):547-559, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.526, + 0.468, + 0.579 + ], + "angle": 0, + "content": "[24] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.582, + 0.468, + 0.677 + ], + "angle": 0, + "content": "[25] Shih-Cheng Huang, Liyue Shen, Matthew P Lungren, and Serena Yeung. Gloria: A multimodal global-local representation learning framework for label-efficient medical image recognition. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 3942-3951, 2021. Official Implementation: https://github.com/ marshuang80/gloria." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.679, + 0.468, + 0.746 + ], + "angle": 0, + "content": "[26] Xin Huang, Yu Fang, Mingming Lu, Fengqi Yan, Jun Yang, and Yilu Xu. Dual-ray net: automatic diagnosis of thoracic diseases using frontal and lateral chest x-rays. Journal of Medical Imaging and Health Informatics, 10(2):348-355, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.748, + 0.468, + 0.815 + ], + "angle": 0, + "content": "[27] Sarfaraz Hussein, Kunlin Cao, Qi Song, and Ulas Bagci. Risk stratification of lung nodules using 3d cnn-based multitask learning. In International conference on information processing in medical imaging, pages 249-260. Springer, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.468, + 0.899 + ], + "angle": 0, + "content": "[28] Jeremy Irvin, Pranav Rajpurkar, Michael Ko, Yifan Yu, Silviana Ciurea-Ilicus, Chris Chute, Henrik Marklund, Behzad Haghgoo, Robyn Ball, Katie Shpanskaya, et al. Chexpert: A large chest radiograph dataset with uncertainty labels and expert comparison. In Proceedings of the AAAI conference on artificial intelligence, volume 33, pages 590-597, 2019." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.187 + ], + "angle": 0, + "content": "[29] Saahil Jain, Ashwin Agrawal, Adriel Saporta, Steven Truong, Tan Bui, Pierre Chambon, Yuhao Zhang, Matthew P Lungren, Andrew Y Ng, Curtis Langlotz, et al. Radgraph: Extracting clinical entities and relations from radiology reports. In Thirty-fifth Conference on Neural Information Processing Systems Datasets and Benchmarks Track (Round 1), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.19, + 0.892, + 0.271 + ], + "angle": 0, + "content": "[30] Chao Jia, Yinfei Yang, Ye Xia, Yi-Ting Chen, Zarana Parekh, Hieu Pham, Quoc Le, Yun-Hsuan Sung, Zhen Li, and Tom Duerig. Scaling up visual and vision-language representation learning with noisy text supervision. In International Conference on Machine Learning, pages 4904-4916. PMLR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.274, + 0.892, + 0.314 + ], + "angle": 0, + "content": "[31] AEWP Johnson, Tom Pollard, Roger Mark, Seth Berkowitz, and Steven Horng. Mimic-cxr database. PhysioNet10, 13026:C2JT1Q, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.316, + 0.892, + 0.37 + ], + "angle": 0, + "content": "[32] Junnan Li, Dongxu Li, Caiming Xiong, and Steven Hoi. Blip: Bootstrapping language-image pre-training for unified vision-language understanding and generation. arXiv preprint arXiv:2201.12086, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.372, + 0.892, + 0.44 + ], + "angle": 0, + "content": "[33] Junnan Li, Ramprasaath Selvaraju, Akhilesh Gotmare, Shafiq Joty, Caiming Xiong, and Steven Chu Hong Hoi. Align before fuse: Vision and language representation learning with momentum distillation. Advances in neural information processing systems, 34:9694-9705, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.442, + 0.892, + 0.509 + ], + "angle": 0, + "content": "[34] Liu Li, Mai Xu, Xiaofei Wang, Lai Jiang, and Hanruo Liu. Attention based glaucoma detection: a large-scale database and cnn model. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 10571-10580, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.511, + 0.892, + 0.564 + ], + "angle": 0, + "content": "[35] Liunian Harold Li, Mark Yatskar, Da Yin, Cho-Jui Hsieh, and Kai-Wei Chang. Visualbert: A simple and perform-. mant baseline for vision and language. arXiv preprint arXiv:1908.03557, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.567, + 0.892, + 0.635 + ], + "angle": 0, + "content": "[36] Mingjie Li, Wenjia Cai, Karin Verspoor, Shirui Pan, Xiaodan Liang, and Xiaojun Chang. Cross-modal clinical graph transformer for ophthalmic report generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 20656-20665, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.637, + 0.892, + 0.704 + ], + "angle": 0, + "content": "[37] Xiaomeng Li, Xiaowei Hu, Lequan Yu, Lei Zhu, Chi-Wing Fu, and Pheng-Ann Heng. Canet: cross-disease attention network for joint diabetic retinopathy and diabetic macular edema grading. IEEE transactions on medical imaging, 39(5):1483-1493, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.707, + 0.892, + 0.801 + ], + "angle": 0, + "content": "[38] Xiujun Li, Xi Yin, Chunyuan Li, Pengchuan Zhang, Xiaowei Hu, Lei Zhang, Lijuan Wang, Houdong Hu, Li Dong, Furu Wei, et al. Oscar: Object-semantics aligned pre-training for vision-language tasks. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XXX 16, pages 121-137. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.804, + 0.892, + 0.857 + ], + "angle": 0, + "content": "[39] Qing Liao, Ye Ding, Zoe L Jiang, Xuan Wang, Chunkai Zhang, and Qian Zhang. Multi-task deep convolutional neural network for cancer diagnosis. Neurocomputing, 348:66-73, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.86, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[40] Fenglin Liu, Xian Wu, Shen Ge, Wei Fan, and Yuexian Zou. Exploring and distilling posterior and prior knowledge for radiology report generation. In Proceedings of" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.518, + 0.937 + ], + "angle": 0, + "content": "21381" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.111, + 0.093, + 0.468, + 0.12 + ], + "angle": 0, + "content": "the IEEE/CVF conference on computer vision and pattern recognition, pages 13753-13762, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.469, + 0.188 + ], + "angle": 0, + "content": "[41] Weijie Liu, Peng Zhou, Zhe Zhao, Zhiruo Wang, Qi Ju, Haotang Deng, and Ping Wang. K-bert: Enabling language representation with knowledge graph. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 2901-2908, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.19, + 0.469, + 0.232 + ], + "angle": 0, + "content": "[42] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In International Conference on Learning Representations, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.233, + 0.469, + 0.301 + ], + "angle": 0, + "content": "[43] Gabriel Maicas, Andrew P Bradley, Jacinto C Nascimento, Ian Reid, and Gustavo Carneiro. Training medical image analysis systems like radiologists. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 546-554. Springer, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.303, + 0.469, + 0.371 + ], + "angle": 0, + "content": "[44] Matthew BA McDermott, Tzu Ming Harry Hsu, Wei-Hung Weng, Marzyeh Ghassemi, and Peter Szolovits. Chexpert++: Approximating the chexpert labeler for speed, differentiability, and probabilistic output. In Machine Learning for Healthcare Conference, pages 913-927. PMLR, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.372, + 0.469, + 0.44 + ], + "angle": 0, + "content": "[45] Masahiro Mitsuhara, Hiroshi Fukui, Yusuke Sakashita, Takanori Ogata, Tsubasa Hirakawa, Takayoshi Yamashita, and Hironobu Fujiyoshi. Embedding human knowledge into deep neural network via attention map. arXiv preprint arXiv:1905.03540, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.442, + 0.469, + 0.525 + ], + "angle": 0, + "content": "[46] Yasuhide Miura, Yuhao Zhang, Emily Tsai, Curtis Langlotz, and Dan Jurafsky. Improving factual completeness and consistency of image-to-text radiology report generation. In Proceedings of the 2021 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pages 5288-5304, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.526, + 0.469, + 0.579 + ], + "angle": 0, + "content": "[47] Philip Müller, Georgios Kaissis, Congyu Zou, and Daniel Rückert. Joint learning of localized representations from medical images and reports. arXiv preprint arXiv:2112.02889, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.581, + 0.469, + 0.663 + ], + "angle": 0, + "content": "[48] Maya Pavlova, Naomi Terhljan, Audrey G Chung, Andy Zhao, Siddharth Surana, Hossein Aboutalebi, Hayden Gunraj, Ali Sabri, Amer Alaref, and Alexander Wong. Covid-net cxr-2: An enhanced deep convolutional neural network design for detection of COVID-19 cases from chest x-ray images. Frontiers in Medicine, 9, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.665, + 0.469, + 0.733 + ], + "angle": 0, + "content": "[49] Yifan Peng, Xiaosong Wang, Le Lu, Mohammadhadi Bagheri, Ronald Summers, and Zhiyong Lu. Negbio: a high-performance tool for negation and uncertainty detection in radiology reports. AMIA Summits on Translational Science Proceedings, 2018:188, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.735, + 0.469, + 0.816 + ], + "angle": 0, + "content": "[50] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning, pages 8748-8763. PMLR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.469, + 0.9 + ], + "angle": 0, + "content": "[51] George Shih, Carol C Wu, Safwan S Halabi, Marc D Kohli, Luciano M Prevedello, Tessa S Cook, Arjun Sharma, Judith K Amorosa, Veronica Arteaga, Maya Galperin-Aizenberg, et al. Augmenting the national institutes of health chest radiograph dataset with expert annotations of possible pneumonia. Radiology. Artificial intelligence, 1(1), 2019." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.093, + 0.469, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.176 + ], + "angle": 0, + "content": "[52] Akshay Smit, Saahil Jain, Pranav Rajpurkar, Anuj Pareek, Andrew Y Ng, and Matthew Lungren. Combining automatic labelers and expert annotations for accurate radiology report labeling using bert. In Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP), pages 1500-1519, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.177, + 0.892, + 0.231 + ], + "angle": 0, + "content": "[53] Jiaxing Tan, Yumei Huo, Zhengrong Liang, and Lihong Li. Expert knowledge-infused deep learning for automatic lung nodule detection. Journal of X-ray Science and Technology, 27(1):17-35, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.232, + 0.892, + 0.288 + ], + "angle": 0, + "content": "[54] Haiming Tang, Nanfei Sun, and Yi Li. Deep learning segmentation model for automated detection of the opacity regions in the chest x-rays of the COVID-19 positive patients and the application for disease severity. medRxiv preprint, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.289, + 0.892, + 0.357 + ], + "angle": 0, + "content": "[55] Joseph J Titano, Marcus Badgeley, Javin Schefflein, Margaret Pain, Andres Su, Michael Cai, Nathaniel Swinburne, John Zech, Jun Kim, Joshua Bederson, et al. Automated deep-neural-network surveillance of cranial images for acute neurologic events. Nature medicine, 24(9):1337-1341, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.358, + 0.892, + 0.425 + ], + "angle": 0, + "content": "[56] Ekin Tiu, Ellie Talius, Pujan Patel, Curtis P Langlotz, Andrew Y Ng, and Pranav Rajpurkar. Expert-level detection of pathologies from unannotated chest x-ray images via self-supervised learning. Nature Biomedical Engineering, pages 1-8, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.428, + 0.892, + 0.495 + ], + "angle": 0, + "content": "[57] Kun Wang, Xiaohong Zhang, Sheng Huang, Feiyu Chen, Xiangbo Zhang, and Luwen Huangfu. Learning to recognize thoracic disease in chest x-rays with knowledge-guided deep zoom neural networks. IEEE Access, 8:159790-159805, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.497, + 0.892, + 0.593 + ], + "angle": 0, + "content": "[58] Xiaosong Wang, Yifan Peng, Le Lu, Zhiyong Lu, Mohammadhadi Bagheri, and Ronald M Summers. Chestx-ray8: Hospital-scale chest x-ray database and benchmarks on weakly-supervised classification and localization of common thorax diseases. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2097-2106, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.595, + 0.892, + 0.678 + ], + "angle": 0, + "content": "[59] Zhanyu Wang, Mingkang Tang, Lei Wang, Xiu Li, and Luping Zhou. A medical semantic-assisted transformer for radiographic report generation. In Medical Image Computing and Computer Assisted Intervention-MICCAI 2022: 25th International Conference, Singapore, September 18-22, 2022, Proceedings, Part III, pages 655-664. Springer, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.679, + 0.892, + 0.719 + ], + "angle": 0, + "content": "[60] Zifeng Wang, Zhenbang Wu, Dinesh Agarwal, and Jimeng Sun. Medclip: Contrastive learning from unpaired medical images and text. arXiv preprint arXiv:2210.10163, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.72, + 0.892, + 0.816 + ], + "angle": 0, + "content": "[61] Joy T Wu, Nkechinyere Nneka Agu, Ismini Lourentzou, Arjun Sharma, Joseph Alexander Paguio, Jasper Seth Yao, Edward Christopher Dee, William G Mitchell, Satyananda Kashyap, Andrea Giovannini, et al. Chest imagenome dataset for clinical reasoning. In Thirty-fifth Conference on Neural Information Processing Systems Datasets and Benchmarks Track (Round 2), 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.818, + 0.892, + 0.872 + ], + "angle": 0, + "content": "[62] Xiaozheng Xie, Jianwei Niu, Xuefeng Liu, Zhengsu Chen, Shaojie Tang, and Shui Yu. A survey on incorporating domain knowledge into deep learning for medical image analysis. Medical Image Analysis, 69:101985, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.874, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[63] Yutong Xie, Yong Xia, Jianpeng Zhang, Yang Song, Dagan Feng, Michael Fulham, and Weidong Cai. Knowledge-based" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.52, + 0.937 + ], + "angle": 0, + "content": "21382" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.469, + 0.134 + ], + "angle": 0, + "content": "collaborative deep learning for benign-malignant lung nodule classification on chest ct. IEEE transactions on medical imaging, 38(4):991-1004, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.469, + 0.19 + ], + "angle": 0, + "content": "[64] Shuxin Yang, Xian Wu, Shen Ge, S Kevin Zhou, and Li Xiao. Knowledge matters: Chest radiology report generation with general and specific knowledge. Medical Image Analysis, 80:102510, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.192, + 0.469, + 0.303 + ], + "angle": 0, + "content": "[65] Wenkai Yang, Juanjuan Zhao, Yan Qiang, Xiaotang Yang, Yunyun Dong, Qianqian Du, Guohua Shi, and Muhammad Bilal Zia. Dscgans: Integrate domain knowledge in training dual-path semi-supervised conditional generative adversarial networks and s3vm for ultrasonography thyroid nodules classification. In International conference on medical image computing and computer-assisted intervention, pages 558-566. Springer, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.304, + 0.469, + 0.373 + ], + "angle": 0, + "content": "[66] Fei Yu, Jiji Tang, Weichong Yin, Yu Sun, Hao Tian, Hua Wu, and Haifeng Wang. Ernie-vil: Knowledge enhanced vision-language representations through scene graphs. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 3208-3216, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.375, + 0.469, + 0.456 + ], + "angle": 0, + "content": "[67] Ke Yu, Shantanu Ghosh, Zhexiong Liu, Christopher Deible, and Kayhan Batmanghelich. Anatomy-guided weakly-supervised abnormality localization in chest x-rays. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 658-668. Springer, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.459, + 0.469, + 0.542 + ], + "angle": 0, + "content": "[68] Yuhao Zhang, Hang Jiang, Yasuhide Miura, Christopher D Manning, and Curtis P Langlotz. Contrastive learning of medical visual representations from paired images and text. In Machine Learning for Healthcare, 2022. Highest Starred Implementation: https://github.com/edreisMD/ConVIRT-pytorch." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.542 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.925, + 0.519, + 0.937 + ], + "angle": 0, + "content": "21383" + } + ] +] \ No newline at end of file diff --git a/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/a294a7d4-55de-429f-8329-44c18b938170_origin.pdf b/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/a294a7d4-55de-429f-8329-44c18b938170_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..004303ca560b4963894e4f1cc4659aca031a2a26 --- /dev/null +++ b/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/a294a7d4-55de-429f-8329-44c18b938170_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:08bf82d62d23b416b6c670bd0b1889fa71d611cd5c83c66d2a320c0bde1c88cd +size 615429 diff --git a/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/full.md b/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/full.md new file mode 100644 index 0000000000000000000000000000000000000000..c46bb5a3de300defdeaee2c40dfc3fa7dc3a782f --- /dev/null +++ b/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/full.md @@ -0,0 +1,354 @@ +# MedKLIP: Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis + +Chaoyi Wu $^{1,2}$ , Xiaoman Zhang $^{1,2}$ , Ya Zhang $^{1,2}$ , Yanfeng Wang $^{1,2,\dagger}$ , Weidi Xie $^{1,2,\dagger}$ $^{1}$ Cooperative Medianet Innovation Center, Shanghai Jiao Tong University $^{2}$ Shanghai AI Laboratory $\{\mathrm{wtzxxxxwcy02, xm99sjtu, ya_zhang, wangyanfeng, weidi}\} \mathrm{sjtu.edu.cn}$ https://chaoyi-wu.github.io/MedKLIP/ + +# Abstract + +In this paper, we consider enhancing medical visual-language pre-training (VLP) with domain-specific knowledge, by exploiting the paired image-text reports from the radiological daily practice. In particular, we make the following contributions: First, unlike existing works that directly process the raw reports, we adopt a novel triplet extraction module to extract the medical-related information, avoiding unnecessary complexity from language grammar and enhancing the supervision signals; Second, we propose a novel triplet encoding module with entity translation by querying a knowledge base, to exploit the rich domain knowledge in medical field, and implicitly build relationships between medical entities in the language embedding space; Third, we propose to use a Transformer-based fusion model for spatially aligning the entity description with visual signals at the image patch level, enabling the ability for medical diagnosis; Fourth, we conduct thorough experiments to validate the effectiveness of our architecture, and benchmark on numerous public benchmarks e.g., ChestX-ray14, RSNA Pneumonia, SIIM-ACR Pneumothorax, COVIDx CXR-2, COVID Rural, and EdemaSeverity. In both zero-shot and fine-tuning settings, our model has demonstrated strong performance compared with the former methods on disease classification and grounding. + +# 1. Introduction + +With the rapid development of deep learning, numerous works have been proposed to facilitate computer-aided diagnosis in the medical field [46, 20, 55, 19]. Despite the tremendous progress, these models are normally trained to recognize or segment the structures that fall into a certain closed set of anatomical or disease categories, whenever a new disease comes to be of interest, a costly procedure for data annotation, model re-training are required, fundamen + +![](images/776a2a2efcaae6e8ffac6dacfa1af20fdde1eaf463fe0e458d69a7b3c2c0ab70.jpg) +Figure 1: Our method mainly considers combining medical knowledge with VLP. We propose Triplet Extraction and Entity Translation modules, so that the network can be supervised with detailed entity-level signals. + +tally limiting its practical values. As an alternative, recent research considers to train the model on the corpus, consisting of large amount of multi-modal data, that is generated from daily clinical routine, for instance, the most common example is the dataset of X-ray images with paired radiological reports [18, 28, 31]. + +This paper presents our preliminary investigation on vision-language representation learning in the medical domain, with the goal of better zero-shot disease diagnosis (classification) and grounding. Undoubtedly, these tasks have also been widely investigated in the computer vision community, with significant progress made on developing Foundational Models in the past years, for example, CLIP [50], ALBEF [33], BLIP[32], etc. However, to achieve such a goal in the medical domain, different challenges must be resolved, that requires research efforts from the community: First, data availability, training Foundation Models in computer vision normally require over millions of image-text pairs, while in the medical domain, only a few hundred thousand pairs are available [31]. The limited data challenges language models to understand the reports in free form [6]. Second, the problem considered in computer-aided diagnosis is naturally fine-grained, that requires distinguishing the medical concepts to understand the disease, as a consequence, domain knowledge is essen + +tial; Third, robustness is crucial, it is, therefore, preferable to have explainability, where diagnosis results come along with the visual grounding, to help radiologists understand the system, and build trust between human and machines. + +Existing work in medical VLP (Vision-Language Pretraining) [68, 47, 25, 6] follows a straightforward training paradigm by matching raw reports with image scans, as shown in Fig.1A, ignoring the medical prior knowledge, and, thus, we propose a novel knowledge-enhanced visual-language model as shown in Fig. 1B. First, we propose a triplet extraction module to extract useful medical entities (keywords) from raw reports, and simplify each report into sets of triplets, denoted as {entity, position, exist}. Decomposing reports into triplets leads to an effective representation of the reports with minimal information loss due to the structural prior in reports; Second, we translate the medical entities into fine-grained descriptions by leveraging a well-defined medical word knowledge base, that tends to explain diseases with common vocabulary. Thus, computing text embeddings for these descriptions enables to implicitly establish relationships between medical entities; Third, we view the entities as a query set and adopt a transformer-based architecture for aligning the image patches with entity descriptions, that enables explicit supervision signals at entity level. Consequently, we can simultaneously infer the likelihood of certain diseases with the visual evidence in the form of a spatial heatmap, i.e., providing rough grounding for explainability. + +We pre-train the model on one widely-used medical image-report dataset MIMIC-CXR [31], and rigorously evaluate on the task of disease diagnosis across numerous public benchmarks, e.g., ChestX-ray14 [58], RSNA Pneumonia [51], SIIM-ACR Pneumothorax [1], COVIDx CXR2 [48], COVID Rural [54, 15], and EdemaSeverity [7]. We get state-of-the-art performance on zero-shot classification and grounding on different diseases, spanning different image distributions, with further fine-tuning, our model still exceeds previous models significantly. + +# 2. Related Work + +General Vision-Language Pre-training (VLP) Models. In computer vision, such line of research has gained tremendous success in the recent literature, generally speaking, the developed architectures can either be two-stream [4, 33, 30], i.e., dual encoders, or those based on single-stream methods [35, 9], that favors visual-language fusion. In particular, several works [13, 38, 66] consider considers to combine the commonsense knowledge into the vision-language pre-training, however, in this paper, we focus on medical domain, which is clearly more fine-grained and requires significantly more expertise. + +Medical Named-Entity-Rcognition (NER) Models. Var + +ious natural language processing (NLP) approaches have been proposed to extract information from radiology reports [49, 28, 44, 52]. These early methods considered only the disease, thus causing information loss. Further state-of-the-art works [29, 61] are proposed to extract relationship between different entities without demand of pre-defined close disease set, retaining most of useful information with high accuracy. In weakly supervision [67] and report generation fields [14], NER methods have shown great impact, and greatly inspired us for more effective vision-language pre-training with medical domain knowledge injected. + +Medical Knowledge Enhanced Models. In general NLP, many works considering combining knowledge, e.g., K-BERT [41] while they consider general knowledge more and focuses on language encoding. In medical community, leveraging external medical knowledge to enhance deep learning models is also a quite important topic [62]. Depending the approaches of using medical knowledge, They can be classified into model-based or input-based. In model-based approaches, the authors aim to imitate the radiological or diagnosis practice to design models [34, 23, 57, 26, 45, 21, 12]. While in input-based approaches, the knowledge is treated as an extra input for computing features [65, 63, 53, 11] or to guide the final training loss [8, 27, 37, 39, 43], commonly used in report generation tasks [59, 64, 40, 11, 36]. However, none of these works are targeting on vision-language pre-training in medical domain with image-report. + +Concurrent Works in Medical VLP. Existing medical VLP methods follow the two-stream flow [68, 25, 7, 47, 60, 10], i.e., use contrastive learning and without fusion module, for example, ConVIRT [68] initially proposed to use contrastive loss as a proxy task for aligning the medical scan and corresponding reports, LoVT and GLoRIA then focus on improving the local alignment performance [25, 7]. BioViL notices the language pattern in reports is different from natural texts and re-designs the language model [6]. The recent arxiv preprint, MedCLIP [60], considers leveraging unpaired data to make up data scarcity. The most related to ours is CheXzero [56], which targets at zero-shot diagnosis. Align [10] focuses on leveraging external medical knowledge to improve the performance of VLP model on medical Visual Question Answering (VQA). However, they treat knowledge as an additional loss and we adopt a new training scheme leveraging medical knowledge by aligning entity, instead of raw reports, with images. Despite significant contribution has been made by existing work [68, 25, 7, 47, 60, 56], they still treat medical texts and images as common natural data and do not explicitly leverage the rich prior knowledge from medical domain. In this paper, we consider to incorporate domain knowledge, re-design the pre-training pipeline delicately and target at accurate diagnosis in X-ray scans. + +![](images/184e46e42002293ec887f663549c937d2195280796d5db9df1c9cdf2a9572e59.jpg) +A. Report Pre-processing + +![](images/451617ab1cdd63e7cf8934a4a7fac0f453f4ef445779f596a32b658c20aa624b.jpg) +B. Knowledge-enhanced Triplet Encoding + +![](images/1e1f7ad98701c856502e4577d8ac37167e88115900b73763bd0763e5e9981816.jpg) +C. Training Flow +Figure 2: The whole framework of our method. We first pre-process the report into triplets leveraging triplet extraction module. Then we encode the extracted triplets and it is worth emphasizing that we translate the entities into detailed descriptions during encoding, by querying the medical knowledge base. Finally we change the training flow with triplets, i.e., we query a transformer-based fusion module at entity level, which provides more detailed supervision signals. + +# 3. Method + +In this section, we start by describing the considered problem scenario in Sec. 3.1, followed by our report pre-process operation with triplet extraction in Sec. 3.2. Then we introduce our proposed knowledge-enhanced architecture in Sec. 3.3, including, visual encoder, knowledge-enhanced triplet encoder, and the fusion module for aligning visual-language signals. In Sec. 3.4, we describe the training procedure with the paired image-reports sourced from the daily routine X-ray scans and, in Sec.3.5, we introduce the procedure for inference. + +# 3.1. Problem Scenario + +Assuming we are given a training set with $N$ samples, i.e., $\mathcal{D}_{\mathrm{train}} = \{(\mathcal{X}_1,\mathcal{T}_1),\ldots ,(\mathcal{X}_N,\mathcal{T}_N)\}$ , where $\mathcal{X}_i,\mathcal{T}_i$ refer to the X-ray image and its corresponding medical report generated in the daily routine scans, respectively, our goal is to train a visual-language model that enables us to diagnose the existence of certain diseases and localize the visual evidence spatially. Specifically, at inference time, we can freely ask the system to identify the likelihood of the patient getting a certain disease (seen or unseen during training): + +$$ +\hat {s} _ {i}, \hat {m} _ {i} = \Phi_ {\text {f u s i o n}} \left(\Phi_ {\text {v i s u a l}} \left(\mathcal {X} _ {i}\right), \Phi_ {\text {t e x t u a l}} ([ \text {d e s c r i p t i o n} ])\right), \tag {1} +$$ + +where $\mathcal{X}_i\in \mathbb{R}^{H\times W\times 3}$ refers to an image sample from the test set, with $H,W$ denoting height and width respectively. $\hat{s}_i\in [0,1]$ refers to the inferred likelihood of the patient having a certain disease indicated by the input description, and $\hat{m}_i\in \mathbb{R}^{H\times W\times 1}$ denotes a predicted spatial heatmap, with high activation on pixels that potentially provide the visual indication for such disease. In the following section, we will introduce our report pre-process operation with triplet extraction. + +# 3.2. Report Pre-processing + +To start with, we propose to pre-process medical reports with a Triplet Extraction module by removing the unnecessary complexity from language grammar. Note that, we hereon only consider single sampled image-reports pair $(\mathcal{X}_i,\mathcal{T}_i)$ , and ignore the subscript in notations for simplicity. + +We condense the original reports with an off-shelf medical Named Entity Recognition (NER) method, namely RadGraph [29, 67], transforming reports into a set of triplets, as shown in Figure 2A. In detail, the medical key words can be extracted and classified as "entity" or "position" with the NER module. "Entity" refers to some clinical observations, like "Opacity". "Position" refers to the anatomical body part that occurs in a radiology report, like "right lower lobe". Besides, the NER module will also provide an "exist" label to conclude whether an entity is claimed to be exist, absent or uncertain in reports. Based on this, we can use a set of triplets, i.e., {entity, position, exist}, to reformulate the sentence in reports, for example, the triplet {Opacity, Right lower lobe, True} represents "It is true that there is opacity located at right lower lobe". Note that, the triplets with a specific "position" are not always termed as True in "exist" as radiologists may point out entities absent at some specific position. + +Therefore, given a report $\mathcal{T}$ with multiple sentences, $\mathcal{T} = \{s_1,s_2,\dots ,s_M\}$ , the extraction module independently operates on each of the sentences, and construct a number of triplets from the report: + +$$ +\Phi_ {\mathrm {e x}} \left(s _ {j}\right) = \left\{\text {e n t i t y} _ {n}, \text {p o s i t i o n} _ {n}, \text {e x i s t} _ {n} \right\}, n \in [ 0, t _ {j} ], \tag {2} +$$ + +where $t_j$ represents the total number of entities contained in one sentence, with $n = 0$ indicating the special case that there is no valid entity. After the triplet extraction, each report is equal to a set of triplets. + +Discussion. In contrast to natural texts, information in medical reports tends to be more condensed, with radiologists pointing out the existence of abnormality and their positions + +in the image. Meanwhile, medical terminologies tend to be professional, and within certain vocabulary (mostly listed in UMLS [5]), specially designed NER methods [29] demonstrate great performance on reports. Therefore, adopting the Triplet Extraction operation in medical VLP can avoid unnecessary complexity from understanding grammar, while still retaining the useful information in reports. + +# 3.3. Architecture + +In this section, we detail our proposed framework, consisting of three components, namely, visual encoding, knowledge-enhanced triplet encoding, and fusion module, as shown in Fig. 2B and Fig. 2C. + +# 3.3.1 Visual Encoding + +Given an X-ray image scan $\mathcal{X} \in \mathbb{R}^{H \times W \times 3}$ , we can compute the features with a visual backbone: + +$$ +\mathcal {V} = \Phi_ {\text {v i s u a l}} (\mathcal {X}) \in \mathbb {R} ^ {h \times w \times d}, \tag {3} +$$ + +$h, w, d$ refer to the height, width, and feature dimension of the output, in our case, we adopt ResNet-50 as the visual backbone, and take the output from the 4th residual block. Note that, we make the architectural choice for fair comparison with existing work [68, 47, 25, 6], while other visual backbones, e.g., ViT [17], can equally be applied. + +# 3.3.2 Knowledge-enhanced Triplet Encoding + +The goal of this module is to encode the triplets extracted from reports by incorporating medical domain knowledge as shown in Fig.2B. + +Given a triplet as $\{\text{entity}, \text{position}, \text{exist}\}$ , it is easy to code the "exist" as it only has three outcomes. We use $l \in \{0, 1, -1\}$ tockenize it, 1 for True, 0 for False, -1 for uncertain. For the "entity" words, we translate them into detailed descriptions by querying some easy-access medical knowledge bases [12], e.g., Description([“Pneumonia”]) = "It is a condition of the lung primarily ... present with opacities and pleural effusion ...". Despite its simplicity, converting the entities into descriptions is crucial for more reliable and zero-shot diagnosis, as it further decomposes the professional medical entities into basic attributes that are shared by different diseases, encouraging the model to capture a deep understanding of the visual evidence. For the "position" words, we use a prompt as "It is located at $\{\text{position}\}$ " to form a sentence. Finally, we use ClinicalBERT [3] as a pre-trained text encoder, to compute the embedding for the "entity" and "position", and then adopt a linear MLP to + +project the embedding to desired dimensions: + +$$ +e = \Phi_ {\text {t e x t u a l}} (\text {D e s c r i p t i o n} (\{\text {e n t i t y} \})) \in \mathbb {R} ^ {d}, \tag {4} +$$ + +$$ +p = \Phi_ {\text {t e x t u a l}} \left(" \text {I t i s l o c a t e d a t} \{\text {p o s i t i o n} \}\right) \in \mathbb {R} ^ {d ^ {\prime}}. \tag {5} +$$ + +Each triplet has now been embedded into $\{e,p,l\}$ . + +Discussion. The extracted entities are medical terminologies that are only understandable to audiences with a medical background, while enriching them with detailed descriptions helps the model to capture a deep understanding of visual evidence for diseases. Such patterns can be generalized across diseases, as many attribute descriptions tend to be shared, enabling the model to build implicit relationships on seen classes and understand descriptions for unseen ones. + +# 3.3.3 Fusion Module + +With the triplets from reports, we can supervise the model on the entity level instead of the entire report level. The "position" and "exist" parts in triplets can be naturally seen as more fine-grained supervision labels. Specifically, we adopt a Transformer-based architecture, use the embedding of entities as query, iteratively attending the image embeddings, and output exist and position predictions of entities. + +In detail, we select the top $|Q|$ most commonly appearing entities' embeddings in all training reports, to form an entity query set $Q = \{e_1, e_2, \dots, e_{|Q|}\}$ . The details of the entity query set is provided in the supplementary material (Sec. A). Then $Q$ will be passed into a fusion module with the image representation $\mathcal{V}$ for alignment. The fusion module consists of multiple Transformer Decoder layers, with $Q$ as Query, and $\mathcal{V}$ as Key and Value. The outputs are further fed into two MLPs, independently infer the existence of the entity and the entity's position: + +$$ +\left\{\hat {s}, \hat {p}, \hat {m} \right\} = \Phi_ {\text {f u s i o n}} (\mathcal {V}, Q), \tag {6} +$$ + +where $\hat{s} \in \mathbb{R}^{|Q|}$ represents the existence prediction for each entity query, and $\hat{p} \in \mathbb{R}^{|Q| \times d'}$ represents the predicted position for all entities. Note that, $\hat{m} \in \mathbb{R}^{H \times W}$ denotes the average of the cross-attention maps sourced from Transformer layers and is up-sampled to the size of input image with nearest interpolation. $\hat{m}$ is used for grounding at inference, as it naturally acts as a segmentation heatmap. During training, we will not directly calculate any loss on it. + +Discussion. Adopting Transformer decoder enables to compute correspondences between entities and images at patch-level. Consequently, image features $\mathcal{V}$ are more suitable for downstream segmentation tasks and the average of cross-attention maps in each layers can be used directly for zero-shot grounding, providing explainable for diagnosis. Besides, the default self-attention on queries in Transformer structure can also build relationships across entities. + +# 3.4. Training + +Given a set of encoded triplets $\{e,p,l\}$ extracted from the pairing reports $\mathcal{T}$ , we can compute training loss on the output of fusion module. For the existence prediction $\hat{s}$ , we use binary cross-entropy with the corresponding "exist" labels $l$ , and if $l$ is $-1$ we just pass this label, denoted as $\mathcal{L}_{\mathrm{cls}}$ . To supervise the position prediction for each entity query, we adopt contrastive learning. We form a position set with top $|P|$ common position embeddings as a position set, $P = \{p_{1},p_{2},\dots ,p_{|P|}\}$ , randomly sample $M$ negative position embeddings from it, and use the corresponding position embedding $p$ from triplets as positive: + +$$ +\mathcal {L} _ {\mathrm {l o c}} = - \frac {1}{| Q |} \sum_ {k = 1} ^ {| Q |} \frac {e ^ {\langle \hat {p} _ {k} , p _ {k} \rangle}}{e ^ {\langle \hat {p} _ {k} , p _ {k} \rangle} + \sum_ {u = 1} ^ {M} e ^ {\langle \hat {p} _ {k} , P _ {\mathcal {I} (k , u)} \rangle}}, \tag {7} +$$ + +where $\langle \cdot, \cdot \rangle$ represents the inner product of two vectors and $\mathcal{I}(\cdot, \cdot)$ is a random index sampling function. The position embeddings are un-normalized in calculation. Note that, some entities may not be mentioned in the report and thus, we can not find corresponding labels in triplets. We simply ignore the corresponding predictions while computing loss. + +The final loss is the sum of the two: + +$$ +\mathcal {L} _ {\text {t o t a l}} = \alpha_ {1} \mathcal {L} _ {\text {l o c}} + \alpha_ {2} \mathcal {L} _ {\text {c l s}}, \tag {8} +$$ + +where $\alpha_{1},\alpha_{2}$ refer to two hyper-parameters controlling the ratio of the two losses, and we set them to be 1.0 by default. + +Discussion. In contrast to the existing approaches [68] that align images with entire reports, our training paradigm with triplets provides supervision at a more fine-grained entity level, rather than the global alignment between image and reports as has often done in existing approaches. + +# 3.5. Inference + +At inference time, given a test image, we can directly infer the existence of certain entities/disease, and ground their visual evidence. In particular, for the entities that have appeared in the entity query set $Q$ , we simply adopt the corresponding elements from $Q$ , while for those unseen ones, we replace the entity with a brief description provided by the user, and treat it as an extra query added to entity query set $Q$ , resembling zero-shot inference. The existence output $\hat{s}$ can be directly applied for classification, the average cross-attention $\hat{m}$ between the target entity and the visual features are used for grounding. + +# 4. Experiment + +In this section, we start by introducing the dataset used for experiments, e.g., pre-training, and various downstream datasets. Then we describe the implementation details and the considered baselines. + +# 4.1. Pre-training Dataset + +MIMIC-CXR v2 [31, 22] consists of over 227k studies of paired image-report data, they are sourced from 65,379 patients at different scanning. Each study can have one or two images (different scan views), totaling 377,110 images. + +# 4.2. Datasets for Downstream Tasks + +ChestX-ray14 [58] contains 112,120 frontal-view X-ray images of 30,805 unique patients, collected from the year of 1992 to 2015 by NIH(National Institutes of Health), with labels of 14 common diseases provided. We split the dataset into $0.8 / 0.1 / 0.1$ for train-valid/test. + +RSNA Pneumonia [51] contains more than 260k frontal-view chest X-rays with corresponding pneumonia opacity masks collected by RSNA (Radiological Society of North America). Commonly, it is treated as a classification tasks [25, 6]. We split the dataset into $0.6 / 0.2 / 0.2$ for train-valid/test. + +SIIM-ACR Pneumothorax [1] contains more than 12k frontal-view chest X-rays with pneumothorax masks collected by SIIM-ACR (Society for Imaging Informatics in Medicine and American College of Radiology). Similarly to RSNA Pneumonia dataset, it can be both used as classification and segmentation tasks. We split the dataset into 0.6/0.2/0.2 for train-valid/test. + +COVIDx CXR-2 [48] and COVID Rural [54, 15] aim to evaluate on diagnosing COVID-19. COVIDx CXR-3 contains 29,986 images from 16,648 patients with COVID-19 classification labels. We use it as a classification dataset and split it into $0.7 / 0.2 / 0.1$ for train-valid/test. Additionally, we use COVID Rural dataset for COVID-19 segmentation. It contains more than 200 chest X-rays with segmentation masks, and we split it into $0.6 / 0.2 / 0.2$ for train-valid/test. + +Edema Severity [7] contains 6,524 examples from MIMIC-CXR with pulmonary edema severity labels (0 to 3, increasing severity) extracted from the radiology reports. Of these, 141 radiologists were examined by radiologists, and consensus was reached on severity level. It can be seen as a typical fine-grained classification task. We split the dataset into $0.6 / 0.2 / 0.2$ for train-valid/test. + +# 4.3. Implementation + +This section describes the implementation for architectures. In Pre-training, the triplets extraction module and text encoders used in triplets encoding are all fixed, while the visual encoder and fusion module are trained end-to-end on the image-text pairs. In Fine-tuning, we adopt ResNet50 [24] initialized with image encoder for classification, and ResUNet [16] initialize its encoder with our pretrained image encoder for segmentation. More details about exact values of different parameters and training progress can be found in supplementary material (Sec. B) + +
Dataset MethodsRSNA PneumoniaSIIM-ACR PneumothoraxChestX-ray14
AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑
ConVIRT [68]0.80420.58420.76110.64310.43290.57000.61010.16280.7102
GLoRIA [25]0.71450.49010.71290.53420.38230.40470.66100.17320.7700
BioViL [6]0.82800.58330.76690.70790.48550.69090.69120.19310.7916
CheXzero [56]0.85790.62110.79420.68790.47040.54660.72960.21410.8278
Ours0.86940.63420.80020.89240.68330.84280.76760.25250.8619
+ +Table 1: Comparison with other state-of-the-art methods on zero-shot classification task. AUC, F1 and ACC scores are reported. For ChestX-ray14, the metrics all refer to the macro average on the 14 diseases. + +
Prompt Type MethodsDirect Covid-19Covid-19 Description
AUC↑F1↑ACC↑AUC↑F1↑ACC↑
ConVIRT [68]0.61590.70570.61130.52080.69020.5266
GLoRIA [25]0.63190.69380.57100.66590.70070.6083
BioViL [6]0.61370.69580.54610.53820.69100.5375
CheXzero [56]0.64620.73690.66290.66670.64000.6578
Ours0.65610.70660.59170.73960.76700.7006
+ +Table 2: Comparison with other state-of-the-art methods on zero-shot Covid-19 classification task. AUC, F1 and ACC scores are reported. "Direct Covid-19" refers to directly use "Covid-19" to construct the prompt sentence while "Covid-19 Description" refers to replace the name "Covid-19" with its description. + +# 4.4. Baselines + +We compare with various existing state-of-the-art medical image-text pre-train methods, namely, ConVIRT [68], GLoRIA [25], BioViL [6] and CheXzero [56]. Since ConVIRT and GLoRIA are pre-trained on an in-house dataset, we re-train their models on MIMIC-CXR dataset for fair comparison. For BioViL, we use the officially released models by the authors. For zero-shot setting, we use the prompt as mentioned by BioViL [6] and compare to the very recent method (CheXzero [56]) that has shown to have better zero-shot diagnosis ability than radiologists. For finetuning, we all use the same setting as described in Sec. 4.3. + +# 4.5. Metrics + +AUC, F1 and ACC are measured for classification tasks. F1 comprehensively measures the recall and precision of the model, and ACC is the short of Accuracy. The final binary prediction threshold is chosen to maximise the F1 score. The ACC score is also calculated under this threshold. + +Pointing Game is used for evaluating the grounding performance. In specific, we extract the region with max response in the output heat-map, for one instance, if the region hit the ground-truth mask, it is considered a positive prediction, otherwise negative. Finally, accuracy can be calculated as the pointing game score. + +Dice and IOU are commonly used for segmentation tasks. For zero-shot segmentation, we search the segmentation threshold with 0.01 interval for all methods, and report the maximal Dice score for each model. + +Precision and Recall refer to the detection Precision and Recall. For medical, it is important that lesions are detected even without fine segmentation. Additionally, in some hard cases, especially for the zero-shot setting, Dice and IOU may be too strict to reflect the performance differ + +ence. Precision and recall scores can compensate for these. We choose the IOU threshold as 0.1 to calculate the scores. + +# 5. Results + +In this section, we will report the experimental results. In general, we split the results into two parts: zero-shot setting and fine-tuning setting. In the zero-shot case (Sec. 5.1), we carry out the ablation study and compare it with the other SOTA image-text pre-train methods. We mainly consider classification and segmentation tasks; in the fine-tuning case (Sec. 5.2), we evaluate the model's transferability by fine-tuning the model with $1\%$ , $10\%$ , and $100\%$ data portion. Additionally, we also add a disease grading downstream task, which can be seen as a fine-grade classification task, showing that our pre-trained model can be transferred to the downstream tasks at ease. + +# 5.1. Zero-shot Evaluation + +In this section, we compare our method with other state-of-the-art methods under zero-shot setting, on classification and grounding. Due to the space limitation, we include the entire ablation study in the supplementary material (Sec. C), referring to it for more details and analysis, and all comparisons here are made using our best model with position contrastive loss and entity description encoder. + +# 5.1.1 Classification + +Seen Diseases. As shown in Tab. 1, we compare with existing methods on three widely-used datasets, demonstrating consistent performance improvement. Specifically, on pneumonia and pneumothorax datasets, despite the images being collected by different clinics with different diseases, our model improves the AUC score from 0.83 to 0.87 on + +
MethodsPointing Game↑Recall↑Precision↑IoU↑Dice↑
GLoRIA [25]0.76070.83300.16210.21820.3468
BioViL [6]0.83420.85210.50340.30290.4386
Ours0.87210.86610.64200.31720.4649
+ +(a) Zero-shot grounding on Pneumonia + +
MethodsPointing Game↑Recall↑Precision↑
GLoRIA [25]0.06510.23770.0585
BioViL [6]0.02520.19630.1429
Ours0.19750.35620.1940
+ +(b) Zero-shot grounding on Pneumothorax +Table 3: Comparison with other state-of-the-art methods on zero-shot region grounding tasks. (a) shows the results on RSNA Pneumonia dataset. (b) shows the results on SIIM-ACR Pneumothorax dataset. The pneumothorax region tends to be thin and narrow and much more challenging for grounding, we thus only consider pointing game, recall, and precision. Our method can achieve better performance on different metrics, especially on the pointing game score. ConVIRT and CheXzero can not realize this function. + +
Prompt Type MethodsDirect COVID-19Covid-19 Description
Pointing Game↑Recall↑Precision↑IoU↑Dice↑Pointing Game↑AR↑AP↑IoU↑Dice↑
GLoRIA [25]0.03640.29060.10730.06450.11410.27270.28210.13360.05960.1075
BioViL [6]0.40000.25640.27030.11980.19670.18180.23930.16370.08610.1427
Ours0.18180.18800.14970.07470.12890.58180.52140.49590.13730.2278
+ +Table 4: Comparison with other state-of-the-art methods on zero-shot Covid-19 opacity region grounding task. "Direct COVID-19" refers to directly use "Covid-19" to construct the prompt sentence for entity encoding while "Covid-19 Description" refers to replace the name "Covid-19" with its description. Our method can achieve better performance on different metrics. + +RSNA pneumonia dataset and from 0.71 to 0.89 on SIIM-ACR pneumothorax dataset, as shown in Tab. 1. This shows that our method can better deal with the multi-center and multi-disease data distribution in medical. While on ChestX-ray14 dataset, we improve the average AUC scores from 0.69 to 0.77, we refer the reader to supplementary material (Sec. D) for detailed comparison of 14 diseases. + +Unseen Diseases. Here, we are considering a strict setting for openset classification, in particular, we use covid-19 to evaluate the systems. Covid-19 is a new disease that only appeared in 2019, MIMIC-CXR reports collected in the year 2015 do not include any entity of covid-19, thus it requires the system to have the ability to diagnose truly unseen diseases. As shown in Tab. 2, existing approaches that only rely on disease name struggles to make the correct diagnosis. While, our proposed approach, after introducing medical knowledge, i.e., using entity descriptions, can understand the complex medical entity descriptions unseen in the training set, and significantly boost the performance from 0.66 to 0.74 on AUC and from 0.59 to 0.70 on ACC, demonstrating entity translation is vital for unseen diseases. + +# 5.1.2 Grounding + +In addition to the plain diagnosis, explainability can be equally critical in healthcare, improving the reliability and trustiness of the machine learning systems. Here, we consider providing explainability by grounding the abnormality in the prediction and compare against the existing approaches. Similarly, we split the diseases into seen and unseen ones, depending on whether their names have ap + +peared in the medical reports. Specifically, "Pneumonia" and "Pneumothorax" are treated as seen, and "Covid-19" is treated as unseen. Due to the space limitation, we include visualization results in supplementary material (Sec. E). + +Seen Diseases. We show the results for grounding on RSNA Pneumonia opacity and SIIM-ACR Pneumothorax collapse in Tab. 3. As shown in Tab. 3a, our proposed model surpasses existing approaches on all metrics, for example, we improve the pointing game score from 0.83 to 0.87, the detection Recall from 0.85 to 0.87, the detection precision from 0.50 to 0.64, the IOU from 0.30 to 0.32 and the Dice from 0.44 to 0.46. While on SIIM-ACR dataset (Tab. 3b), the pneumothorax region tends to be thin and narrow, localizing it can often be more challenging than that of opacity grounding [6], we thus only consider pointing game, recall, and precision. Similarly, our method can achieve significantly better performance than prior approaches. + +Unseen Diseases. We also conduct the zero-shot grounding experiment on the unseen disease, namely, Covid-19, as shown in Tab. 4. Our model has shown consistent improvements in all metrics, e.g., boosting the pointing game score from 0.40 to 0.58. One observation to be noticed is that, results in Tab. 4 are mostly consistent with those in Tab. 2, i.e., better classification results tend to lead to better grounding. Overall, our model with knowledge-enhanced language encoding has facilitated the visual encoder to learn underlying evidence relating to the diseases, therefore, leading to more interpretable representations than prior approaches. + +
Dataset Data PortionPneumoniaPneumothoraxCovid-19ChestX-ray14
1%10%100%1%10%100%1%10%100%1%10%100%
Scratch0.71070.81500.86260.43470.61200.65710.78610.91620.95540.60050.73650.7924
ConVIRT [68]0.83980.85620.87610.71340.78260.90040.86750.95410.97260.66150.76580.8128
GLoRIA [25]0.85990.86660.88460.74390.85380.90140.90650.93810.97280.67100.76420.8184
BioViL [6]0.82330.85380.88360.69480.77750.86890.89890.95290.97290.69520.75270.8245
Ours0.87310.87990.89310.85270.90710.91880.92240.96570.97290.77210.78940.8323
+ +Table 5: Comparison of AUC scores with other state-of-the-art methods on fine-tuning classification task. The macro average of AUC scores on 14 diseases are reported for ChestX-ray14 dataset. + +
Diseases Data PortionPneumoniaPneumothoraxCovid-19
1%10%100%1%10%100%1%10%100%
Scratch0.43470.60470.70680.21330.33230.74470.14810.23670.3228
ConVIRT [68]0.57060.64910.72010.54060.61210.73520.19950.27240.3737
GLoRIA [25]0.65550.69070.73280.56730.57780.76940.18890.28090.3869
BioViL [6]0.68240.70380.72490.62670.69980.78490.21130.32390.4162
Ours0.70640.71620.75790.66590.72100.79370.24450.35390.4399
+ +Table 6: Comparison of Dice scores with other state-of-the-art methods on fine-tuning segmentation tasks. Three diseases are reported, and for each disease, three data portions, $1\%$ , $10\%$ , $100\%$ are adopted to show the performance change under different data amounts. + +
Methods0123AVG
AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑
Scratch0.76310.70360.67380.53830.35930.32230.66920.43280.70120.84200.56940.87700.70310.51630.6436
ConVIRT [68]0.84530.77690.77930.60990.39380.46290.72020.48430.64450.90470.61540.88090.77000.56760.6919
GLoRIA [25]0.83040.75770.75200.62080.39910.49220.73390.49580.70370.92460.66670.91020.77740.57980.7145
BioViL [6]0.80340.73780.71480.60350.39120.45700.68600.44970.67770.92290.65000.91600.75400.55720.6914
Ours0.85020.76460.75390.66410.41400.53920.76050.52660.70310.88450.62500.91600.78980.58260.7280
+ +Table 7: Comparison with other state-of-the-art methods on fine-tuning edema severity grading multi-class classification task. AUC score is reported in the Table. "0,1,2,3" in the table represents the severity level and final average scores are reported. + +# 5.2. Fine-tuning Evaluation + +In this section, we consider the fine-tuning scenario, with the pre-trained model as initialization, and trained end-to-end on the downstream tasks. We test on three different tasks, namely, classification, segmentation, and grading. In classification and segmentation, the test splits and metrics are the same as in the "zero-shot" section. Grading is a new task we introduce in fine-tuning setting, which can be seen as a fine-grained classification task. + +# 5.2.1 Classification + +We experiment on four different datasets, using $1\%$ , $10\%$ , $100\%$ of the data for fine-tuning, that is consistent with the existing work [68, 25, 6]. As shown in Tab. 5, our model has demonstrated substantial improvements in the AUC scores over the existing approaches across all datasets, reflecting that our pre-trained representation is of higher quality than existing models. We refer the readers to the supplementary material (Sec. D) for more detailed comparison results. + +# 5.2.2 Segmentation + +In Tab. 6, we conduct fine-tuning experiments on three different diseases for segmentation. We pick $1\%$ , $10\%$ , $100\%$ of the data for fine-tuning. For all three different diseases with different image distributions, our methods surpass the existing state-of-the-art methods by a large margin, especially under the low-data regime. + +# 5.2.3 Grading + +Besides diagnosis, grading the disease severity level also plays an important role. Here, we adopt our pre-trained features and train them for the multi-class classification task, with 0 to 3 representing different severity levels. As shown in Tab. 7, for each level, the AUC, F1, and ACC scores are calculated as one class against all other ones, for example, 0 vs $\{1,2,3\}$ . Final macro average scores of four levels are computed. On the majority of severity levels, our method can achieve the best results. + +# 6. Conclusion + +In this paper, we introduce a novel medical knowledge enhanced VLP model. First, we propose a triplet extraction module to extract useful medical-related triplets as more useful supervision signals, simplifying complex raw reports with minimal information loss. Second, we translate the entities in extracted triplets into detailed medical descriptions and embed them with a text encoder enabling the network to understand complex medical expert-level knowledge. Finally, a transformer-based structure is proposed to do local region alignment. In experiments, We evaluate our method on different datasets under various settings. Our method shows strong zero-shot classification and grounding abilities, even facing unseen diseases. Additionally, with finetuning, our method still outperforms state-of-the-art methods significantly, showing the superiority of our method. + +# Acknowledgement + +This work is supported by the National Key R&D Program of China (No. 2022ZD0160702), STCSM (No. 22511106101, No. 18DZ2270700, No. 21DZ1100100), 111 plan (No. BP0719010), and State Key Laboratory of UHD Video and Audio Production and Presentation. + +# References + +[1] Society for imaging informatics in medicine: Siim-acr pneumothorax segmentation. https://www.kaggle.com/c/siim-acr-pneumothorax-segmentation.2019. +[2] Emily Alsentzer, John Murphy, William Boag, Wei-Hung Weng, Di Jin, Tristan Naumann, and Matthew McDermott. Publicly available clinical BERT embeddings. In Proceedings of the 2nd Clinical Natural Language Processing Workshop, pages 72-78, Minneapolis, Minnesota, USA, June 2019. Association for Computational Linguistics. +[3] Emily Alsentzer, John R Murphy, Willie Boag, WeiHung Weng, Di Jin, Tristan Naumann, WA Redmond, and Matthew BA McDermott. Publicly available clinical bert embeddings. *NAACL HLT* 2019, page 72, 2019. +[4] Federico Bianchi, Giuseppe Attanasio, Raphael Pisoni, Silvia Terragni, Gabriele Sarti, and Sri Lakshmi. Contrastive language-image pre-training for the italian language. arXiv preprint arXiv:2108.08688, 2021. +[5] Olivier Bodenreider. The unified medical language system (umlts): integrating biomedical terminology. *Nucleic acids research*, 32(suppl_1):D267–D270, 2004. +[6] Benedikt Boecking, Naoto Usuyama, Shruthi Bannur, Daniel C Castro, Anton Schwaighofer, Stephanie Hyland, Maria Wetscherek, Tristan Naumann, Aditya Nori, Javier Alvarez-Valle, et al. Making the most of text semantics to improve biomedical vision-language processing. In European conference on computer vision, pages 1-21, 2022. Official Implementa + +tion: https://github.com/microsoft/hi-ml/tree/main/hi-ml-multimodal. +[7] Geeticka Chauhan, Ruizhi Liao, William Wells, Jacob Andreas, Xin Wang, Seth Berkowitz, Steven Horng, Peter Szolovits, and Polina Golland. Joint modeling of chest radiographs and radiology reports for pulmonary edema assessment. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 529-539. Springer, 2020. +[8] Sihong Chen, Jing Qin, Xing Ji, Baiying Lei, Tianfu Wang, Dong Ni, and Jie-Zhi Cheng. Automatic scoring of multiple semantic attributes with multi-task feature leverage: a study on pulmonary nodules in ct images. IEEE transactions on medical imaging, 36(3):802-814, 2016. +[9] Yen-Chun Chen, Linjie Li, Licheng Yu, Ahmed El Kholy, Faisal Ahmed, Zhe Gan, Yu Cheng, and Jingjing Liu. Uniter: Universal image-text representation learning. In European conference on computer vision, pages 104-120. Springer, 2020. +[10] Zhihong Chen, Guanbin Li, and Xiang Wan. Align, reason and learn: Enhancing medical vision-and-language pretraining with knowledge. In Proceedings of the 30th ACM International Conference on Multimedia, pages 5152-5161, 2022. +[11] Zhihong Chen, Yan Song, Tsung-Hui Chang, and Xiang Wan. Generating radiology reports via memory-driven transformer. In Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP), pages 1439-1449, 2020. +[12] Hui Cui, Yiyue Xu, Wanlong Li, Linlin Wang, and Henry Duh. Collaborative learning of cross-channel clinical attention for radiotherapy-related esophageal fistula prediction from ct. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 212-220. Springer, 2020. +[13] Yuhao Cui, Zhou Yu, Chunqi Wang, Zhongzhou Zhao, Ji Zhang, Meng Wang, and Jun Yu. Rosita: Enhancing vision-and-language semantic alignments via cross-and intra-modal knowledge integration. In Proceedings of the 29th ACM International Conference on Multimedia, pages 797-806, 2021. +[14] Jean-Benoit Delbrouck, Pierre Chambon, Christian Bluethgen, Emily Tsai, Omar Almusa, and Curtis P Langlotz. Improving the factual correctness of radiology report generation with semantic rewards. arXiv preprint arXiv:2210.12186, 2022. +[15] Shivang Desai, Ahmad Baghal, Thidathip Wongsurawat, Piroon Jenjaroenpun, Thomas Powell, Shaymaa Al-Shukri, Kim Gates, Phillip Farmer, Michael Rutherford, Geri Blake, et al. Chest imaging representing a Covid-19 positive rural us population. Scientific data, 7(1):1-6, 2020. +[16] Foivos I Diakogiannis, François Waldner, Peter Caccetta, and Chen Wu. Resunet-a: A deep learning framework for semantic segmentation of remotely sensed data. ISPRS Journal of Photogrammetry and Remote Sensing, 162:94-114, 2020. +[17] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, + +Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2020. +[18] Jared A Dunnmon, Alexander J Ratner, Khaled Saab, Nishith Khandwala, Matthew Markert, Hersh Sagreiya, Roger Goldman, Christopher Lee-Messer, Matthew P Lungren, Daniel L Rubin, et al. Cross-modal data programming enables rapid medical machine learning. *Patterns*, 1(2):100019, 2020. +[19] Bradley J Erickson, Panagiotis Korfiatis, Zeynettin Akkus, and Timothy L Kline. Machine learning for medical imaging. Radiographics, 37(2):505, 2017. +[20] Andre Esteva, Brett Kuprel, Roberto A Novoa, Justin Ko, Susan M Swetter, Helen M Blau, and Sebastian Thrun. Dermatologist-level classification of skin cancer with deep neural networks. nature, 542(7639):115-118, 2017. +[21] Leyuan Fang, Chong Wang, Shutao Li, Hossein Rabbani, Xiangdong Chen, and Zhimin Liu. Attention to lesion: Lesion-aware convolutional neural network for retinal optical coherence tomography image classification. IEEE transactions on medical imaging, 38(8):1959-1970, 2019. +[22] Ary L Goldberger, Luis AN Amaral, Leon Glass, Jeffrey M Hausdorff, Plamen Ch Ivanov, Roger G Mark, Joseph E Mietus, George B Moody, Chung-Kang Peng, and H Eugene Stanley. Physiobank, physiotoolkit, and physionet: components of a new research resource for complex physiologic signals. circulation, 101(23):e215-e220, 2000. +[23] Ivan Gonzalez-Diaz. Dermaknet: Incorporating the knowledge of dermatologists to convolutional neural networks for skin lesion diagnosis. IEEE journal of biomedical and health informatics, 23(2):547-559, 2018. +[24] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. +[25] Shih-Cheng Huang, Liyue Shen, Matthew P Lungren, and Serena Yeung. Gloria: A multimodal global-local representation learning framework for label-efficient medical image recognition. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 3942-3951, 2021. Official Implementation: https://github.com/ marshuang80/gloria. +[26] Xin Huang, Yu Fang, Mingming Lu, Fengqi Yan, Jun Yang, and Yilu Xu. Dual-ray net: automatic diagnosis of thoracic diseases using frontal and lateral chest x-rays. Journal of Medical Imaging and Health Informatics, 10(2):348-355, 2020. +[27] Sarfaraz Hussein, Kunlin Cao, Qi Song, and Ulas Bagci. Risk stratification of lung nodules using 3d cnn-based multitask learning. In International conference on information processing in medical imaging, pages 249-260. Springer, 2017. +[28] Jeremy Irvin, Pranav Rajpurkar, Michael Ko, Yifan Yu, Silviana Ciurea-Ilicus, Chris Chute, Henrik Marklund, Behzad Haghgoo, Robyn Ball, Katie Shpanskaya, et al. Chexpert: A large chest radiograph dataset with uncertainty labels and expert comparison. In Proceedings of the AAAI conference on artificial intelligence, volume 33, pages 590-597, 2019. + +[29] Saahil Jain, Ashwin Agrawal, Adriel Saporta, Steven Truong, Tan Bui, Pierre Chambon, Yuhao Zhang, Matthew P Lungren, Andrew Y Ng, Curtis Langlotz, et al. Radgraph: Extracting clinical entities and relations from radiology reports. In Thirty-fifth Conference on Neural Information Processing Systems Datasets and Benchmarks Track (Round 1), 2021. +[30] Chao Jia, Yinfei Yang, Ye Xia, Yi-Ting Chen, Zarana Parekh, Hieu Pham, Quoc Le, Yun-Hsuan Sung, Zhen Li, and Tom Duerig. Scaling up visual and vision-language representation learning with noisy text supervision. In International Conference on Machine Learning, pages 4904-4916. PMLR, 2021. +[31] AEWP Johnson, Tom Pollard, Roger Mark, Seth Berkowitz, and Steven Horng. Mimic-cxr database. PhysioNet10, 13026:C2JT1Q, 2019. +[32] Junnan Li, Dongxu Li, Caiming Xiong, and Steven Hoi. Blip: Bootstrapping language-image pre-training for unified vision-language understanding and generation. arXiv preprint arXiv:2201.12086, 2022. +[33] Junnan Li, Ramprasaath Selvaraju, Akhilesh Gotmare, Shafiq Joty, Caiming Xiong, and Steven Chu Hong Hoi. Align before fuse: Vision and language representation learning with momentum distillation. Advances in neural information processing systems, 34:9694-9705, 2021. +[34] Liu Li, Mai Xu, Xiaofei Wang, Lai Jiang, and Hanruo Liu. Attention based glaucoma detection: a large-scale database and cnn model. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 10571-10580, 2019. +[35] Liunian Harold Li, Mark Yatskar, Da Yin, Cho-Jui Hsieh, and Kai-Wei Chang. Visualbert: A simple and perform-. mant baseline for vision and language. arXiv preprint arXiv:1908.03557, 2019. +[36] Mingjie Li, Wenjia Cai, Karin Verspoor, Shirui Pan, Xiaodan Liang, and Xiaojun Chang. Cross-modal clinical graph transformer for ophthalmic report generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 20656-20665, 2022. +[37] Xiaomeng Li, Xiaowei Hu, Lequan Yu, Lei Zhu, Chi-Wing Fu, and Pheng-Ann Heng. Canet: cross-disease attention network for joint diabetic retinopathy and diabetic macular edema grading. IEEE transactions on medical imaging, 39(5):1483-1493, 2019. +[38] Xiujun Li, Xi Yin, Chunyuan Li, Pengchuan Zhang, Xiaowei Hu, Lei Zhang, Lijuan Wang, Houdong Hu, Li Dong, Furu Wei, et al. Oscar: Object-semantics aligned pre-training for vision-language tasks. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XXX 16, pages 121-137. Springer, 2020. +[39] Qing Liao, Ye Ding, Zoe L Jiang, Xuan Wang, Chunkai Zhang, and Qian Zhang. Multi-task deep convolutional neural network for cancer diagnosis. Neurocomputing, 348:66-73, 2019. +[40] Fenglin Liu, Xian Wu, Shen Ge, Wei Fan, and Yuexian Zou. Exploring and distilling posterior and prior knowledge for radiology report generation. In Proceedings of + +the IEEE/CVF conference on computer vision and pattern recognition, pages 13753-13762, 2021. +[41] Weijie Liu, Peng Zhou, Zhe Zhao, Zhiruo Wang, Qi Ju, Haotang Deng, and Ping Wang. K-bert: Enabling language representation with knowledge graph. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 2901-2908, 2020. +[42] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In International Conference on Learning Representations, 2018. +[43] Gabriel Maicas, Andrew P Bradley, Jacinto C Nascimento, Ian Reid, and Gustavo Carneiro. Training medical image analysis systems like radiologists. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 546-554. Springer, 2018. +[44] Matthew BA McDermott, Tzu Ming Harry Hsu, Wei-Hung Weng, Marzyeh Ghassemi, and Peter Szolovits. Chexpert++: Approximating the chexpert labeler for speed, differentiability, and probabilistic output. In Machine Learning for Healthcare Conference, pages 913-927. PMLR, 2020. +[45] Masahiro Mitsuhara, Hiroshi Fukui, Yusuke Sakashita, Takanori Ogata, Tsubasa Hirakawa, Takayoshi Yamashita, and Hironobu Fujiyoshi. Embedding human knowledge into deep neural network via attention map. arXiv preprint arXiv:1905.03540, 2019. +[46] Yasuhide Miura, Yuhao Zhang, Emily Tsai, Curtis Langlotz, and Dan Jurafsky. Improving factual completeness and consistency of image-to-text radiology report generation. In Proceedings of the 2021 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pages 5288-5304, 2021. +[47] Philip Müller, Georgios Kaissis, Congyu Zou, and Daniel Rückert. Joint learning of localized representations from medical images and reports. arXiv preprint arXiv:2112.02889, 2021. +[48] Maya Pavlova, Naomi Terhljan, Audrey G Chung, Andy Zhao, Siddharth Surana, Hossein Aboutalebi, Hayden Gunraj, Ali Sabri, Amer Alaref, and Alexander Wong. Covid-net cxr-2: An enhanced deep convolutional neural network design for detection of COVID-19 cases from chest x-ray images. Frontiers in Medicine, 9, 2022. +[49] Yifan Peng, Xiaosong Wang, Le Lu, Mohammadhadi Bagheri, Ronald Summers, and Zhiyong Lu. Negbio: a high-performance tool for negation and uncertainty detection in radiology reports. AMIA Summits on Translational Science Proceedings, 2018:188, 2018. +[50] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning, pages 8748-8763. PMLR, 2021. +[51] George Shih, Carol C Wu, Safwan S Halabi, Marc D Kohli, Luciano M Prevedello, Tessa S Cook, Arjun Sharma, Judith K Amorosa, Veronica Arteaga, Maya Galperin-Aizenberg, et al. Augmenting the national institutes of health chest radiograph dataset with expert annotations of possible pneumonia. Radiology. Artificial intelligence, 1(1), 2019. + +[52] Akshay Smit, Saahil Jain, Pranav Rajpurkar, Anuj Pareek, Andrew Y Ng, and Matthew Lungren. Combining automatic labelers and expert annotations for accurate radiology report labeling using bert. In Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP), pages 1500-1519, 2020. +[53] Jiaxing Tan, Yumei Huo, Zhengrong Liang, and Lihong Li. Expert knowledge-infused deep learning for automatic lung nodule detection. Journal of X-ray Science and Technology, 27(1):17-35, 2019. +[54] Haiming Tang, Nanfei Sun, and Yi Li. Deep learning segmentation model for automated detection of the opacity regions in the chest x-rays of the COVID-19 positive patients and the application for disease severity. medRxiv preprint, 2020. +[55] Joseph J Titano, Marcus Badgeley, Javin Schefflein, Margaret Pain, Andres Su, Michael Cai, Nathaniel Swinburne, John Zech, Jun Kim, Joshua Bederson, et al. Automated deep-neural-network surveillance of cranial images for acute neurologic events. Nature medicine, 24(9):1337-1341, 2018. +[56] Ekin Tiu, Ellie Talius, Pujan Patel, Curtis P Langlotz, Andrew Y Ng, and Pranav Rajpurkar. Expert-level detection of pathologies from unannotated chest x-ray images via self-supervised learning. Nature Biomedical Engineering, pages 1-8, 2022. +[57] Kun Wang, Xiaohong Zhang, Sheng Huang, Feiyu Chen, Xiangbo Zhang, and Luwen Huangfu. Learning to recognize thoracic disease in chest x-rays with knowledge-guided deep zoom neural networks. IEEE Access, 8:159790-159805, 2020. +[58] Xiaosong Wang, Yifan Peng, Le Lu, Zhiyong Lu, Mohammadhadi Bagheri, and Ronald M Summers. Chestx-ray8: Hospital-scale chest x-ray database and benchmarks on weakly-supervised classification and localization of common thorax diseases. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2097-2106, 2017. +[59] Zhanyu Wang, Mingkang Tang, Lei Wang, Xiu Li, and Luping Zhou. A medical semantic-assisted transformer for radiographic report generation. In Medical Image Computing and Computer Assisted Intervention-MICCAI 2022: 25th International Conference, Singapore, September 18-22, 2022, Proceedings, Part III, pages 655-664. Springer, 2022. +[60] Zifeng Wang, Zhenbang Wu, Dinesh Agarwal, and Jimeng Sun. Medclip: Contrastive learning from unpaired medical images and text. arXiv preprint arXiv:2210.10163, 2022. +[61] Joy T Wu, Nkechinyere Nneka Agu, Ismini Lourentzou, Arjun Sharma, Joseph Alexander Paguio, Jasper Seth Yao, Edward Christopher Dee, William G Mitchell, Satyananda Kashyap, Andrea Giovannini, et al. Chest imagenome dataset for clinical reasoning. In Thirty-fifth Conference on Neural Information Processing Systems Datasets and Benchmarks Track (Round 2), 2021. +[62] Xiaozheng Xie, Jianwei Niu, Xuefeng Liu, Zhengsu Chen, Shaojie Tang, and Shui Yu. A survey on incorporating domain knowledge into deep learning for medical image analysis. Medical Image Analysis, 69:101985, 2021. +[63] Yutong Xie, Yong Xia, Jianpeng Zhang, Yang Song, Dagan Feng, Michael Fulham, and Weidong Cai. Knowledge-based + +collaborative deep learning for benign-malignant lung nodule classification on chest ct. IEEE transactions on medical imaging, 38(4):991-1004, 2018. +[64] Shuxin Yang, Xian Wu, Shen Ge, S Kevin Zhou, and Li Xiao. Knowledge matters: Chest radiology report generation with general and specific knowledge. Medical Image Analysis, 80:102510, 2022. +[65] Wenkai Yang, Juanjuan Zhao, Yan Qiang, Xiaotang Yang, Yunyun Dong, Qianqian Du, Guohua Shi, and Muhammad Bilal Zia. Dscgans: Integrate domain knowledge in training dual-path semi-supervised conditional generative adversarial networks and s3vm for ultrasonography thyroid nodules classification. In International conference on medical image computing and computer-assisted intervention, pages 558-566. Springer, 2019. +[66] Fei Yu, Jiji Tang, Weichong Yin, Yu Sun, Hao Tian, Hua Wu, and Haifeng Wang. Ernie-vil: Knowledge enhanced vision-language representations through scene graphs. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 3208-3216, 2021. +[67] Ke Yu, Shantanu Ghosh, Zhexiong Liu, Christopher Deible, and Kayhan Batmanghelich. Anatomy-guided weakly-supervised abnormality localization in chest x-rays. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 658-668. Springer, 2022. +[68] Yuhao Zhang, Hang Jiang, Yasuhide Miura, Christopher D Manning, and Curtis P Langlotz. Contrastive learning of medical visual representations from paired images and text. In Machine Learning for Healthcare, 2022. Highest Starred Implementation: https://github.com/edreisMD/ConVIRT-pytorch. \ No newline at end of file diff --git a/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/images.zip b/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..ecb851c3189bf5a6a11f1c507176b96be5dc5f31 --- /dev/null +++ b/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:df5a5176d588f4393a08e5ddf901c2ae04418cb7ba87170d120f9baed0dfb883 +size 476995 diff --git a/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/layout.json b/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..caf99250e41bc9514648a78df1c1ddff1251db83 --- /dev/null +++ b/2023/MedKLIP_ Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis/layout.json @@ -0,0 +1,9179 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 113, + 103, + 481, + 140 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 113, + 103, + 481, + 140 + ], + "spans": [ + { + "bbox": [ + 113, + 103, + 481, + 140 + ], + "type": "text", + "content": "MedKLIP: Medical Knowledge Enhanced Language-Image Pre-Training for X-ray Diagnosis" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "spans": [ + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "text", + "content": "Chaoyi Wu" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "inline_equation", + "content": "^{1,2}" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "text", + "content": ", Xiaoman Zhang" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "inline_equation", + "content": "^{1,2}" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "text", + "content": ", Ya Zhang" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "inline_equation", + "content": "^{1,2}" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "text", + "content": ", Yanfeng Wang" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "inline_equation", + "content": "^{1,2,\\dagger}" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "text", + "content": ", Weidi Xie" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "inline_equation", + "content": "^{1,2,\\dagger}" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "text", + "content": "Cooperative Medianet Innovation Center, Shanghai Jiao Tong University " + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "text", + "content": "Shanghai AI Laboratory " + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "inline_equation", + "content": "\\{\\mathrm{wtzxxxxwcy02, xm99sjtu, ya_zhang, wangyanfeng, weidi}\\} \\mathrm{sjtu.edu.cn}" + }, + { + "bbox": [ + 53, + 159, + 545, + 218 + ], + "type": "text", + "content": " https://chaoyi-wu.github.io/MedKLIP/" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 245, + 192, + 258 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 245, + 192, + 258 + ], + "spans": [ + { + "bbox": [ + 143, + 245, + 192, + 258 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 270, + 290, + 558 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 270, + 290, + 558 + ], + "spans": [ + { + "bbox": [ + 47, + 270, + 290, + 558 + ], + "type": "text", + "content": "In this paper, we consider enhancing medical visual-language pre-training (VLP) with domain-specific knowledge, by exploiting the paired image-text reports from the radiological daily practice. In particular, we make the following contributions: First, unlike existing works that directly process the raw reports, we adopt a novel triplet extraction module to extract the medical-related information, avoiding unnecessary complexity from language grammar and enhancing the supervision signals; Second, we propose a novel triplet encoding module with entity translation by querying a knowledge base, to exploit the rich domain knowledge in medical field, and implicitly build relationships between medical entities in the language embedding space; Third, we propose to use a Transformer-based fusion model for spatially aligning the entity description with visual signals at the image patch level, enabling the ability for medical diagnosis; Fourth, we conduct thorough experiments to validate the effectiveness of our architecture, and benchmark on numerous public benchmarks e.g., ChestX-ray14, RSNA Pneumonia, SIIM-ACR Pneumothorax, COVIDx CXR-2, COVID Rural, and EdemaSeverity. In both zero-shot and fine-tuning settings, our model has demonstrated strong performance compared with the former methods on disease classification and grounding." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 579, + 128, + 592 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 579, + 128, + 592 + ], + "spans": [ + { + "bbox": [ + 47, + 579, + 128, + 592 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 599, + 287, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 599, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 599, + 287, + 696 + ], + "type": "text", + "content": "With the rapid development of deep learning, numerous works have been proposed to facilitate computer-aided diagnosis in the medical field [46, 20, 55, 19]. Despite the tremendous progress, these models are normally trained to recognize or segment the structures that fall into a certain closed set of anatomical or disease categories, whenever a new disease comes to be of interest, a costly procedure for data annotation, model re-training are required, fundamen" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 307, + 244, + 545, + 340 + ], + "blocks": [ + { + "bbox": [ + 307, + 244, + 545, + 340 + ], + "lines": [ + { + "bbox": [ + 307, + 244, + 545, + 340 + ], + "spans": [ + { + "bbox": [ + 307, + 244, + 545, + 340 + ], + "type": "image", + "image_path": "776a2a2efcaae6e8ffac6dacfa1af20fdde1eaf463fe0e458d69a7b3c2c0ab70.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 351, + 547, + 400 + ], + "lines": [ + { + "bbox": [ + 305, + 351, + 547, + 400 + ], + "spans": [ + { + "bbox": [ + 305, + 351, + 547, + 400 + ], + "type": "text", + "content": "Figure 1: Our method mainly considers combining medical knowledge with VLP. We propose Triplet Extraction and Entity Translation modules, so that the network can be supervised with detailed entity-level signals." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 411, + 546, + 484 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 411, + 546, + 484 + ], + "spans": [ + { + "bbox": [ + 304, + 411, + 546, + 484 + ], + "type": "text", + "content": "tally limiting its practical values. As an alternative, recent research considers to train the model on the corpus, consisting of large amount of multi-modal data, that is generated from daily clinical routine, for instance, the most common example is the dataset of X-ray images with paired radiological reports [18, 28, 31]." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 486, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 486, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 486, + 547, + 713 + ], + "type": "text", + "content": "This paper presents our preliminary investigation on vision-language representation learning in the medical domain, with the goal of better zero-shot disease diagnosis (classification) and grounding. Undoubtedly, these tasks have also been widely investigated in the computer vision community, with significant progress made on developing Foundational Models in the past years, for example, CLIP [50], ALBEF [33], BLIP[32], etc. However, to achieve such a goal in the medical domain, different challenges must be resolved, that requires research efforts from the community: First, data availability, training Foundation Models in computer vision normally require over millions of image-text pairs, while in the medical domain, only a few hundred thousand pairs are available [31]. The limited data challenges language models to understand the reports in free form [6]. Second, the problem considered in computer-aided diagnosis is naturally fine-grained, that requires distinguishing the medical concepts to understand the disease, as a consequence, domain knowledge is essen" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 703, + 130, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 703, + 130, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 703, + 130, + 712 + ], + "type": "text", + "content": "†: Corresponding author." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "21372" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 286, + 119 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 286, + 119 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 286, + 119 + ], + "type": "text", + "content": "tial; Third, robustness is crucial, it is, therefore, preferable to have explainability, where diagnosis results come along with the visual grounding, to help radiologists understand the system, and build trust between human and machines." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 121, + 286, + 407 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 121, + 286, + 407 + ], + "spans": [ + { + "bbox": [ + 49, + 121, + 286, + 407 + ], + "type": "text", + "content": "Existing work in medical VLP (Vision-Language Pretraining) [68, 47, 25, 6] follows a straightforward training paradigm by matching raw reports with image scans, as shown in Fig.1A, ignoring the medical prior knowledge, and, thus, we propose a novel knowledge-enhanced visual-language model as shown in Fig. 1B. First, we propose a triplet extraction module to extract useful medical entities (keywords) from raw reports, and simplify each report into sets of triplets, denoted as {entity, position, exist}. Decomposing reports into triplets leads to an effective representation of the reports with minimal information loss due to the structural prior in reports; Second, we translate the medical entities into fine-grained descriptions by leveraging a well-defined medical word knowledge base, that tends to explain diseases with common vocabulary. Thus, computing text embeddings for these descriptions enables to implicitly establish relationships between medical entities; Third, we view the entities as a query set and adopt a transformer-based architecture for aligning the image patches with entity descriptions, that enables explicit supervision signals at entity level. Consequently, we can simultaneously infer the likelihood of certain diseases with the visual evidence in the form of a spatial heatmap, i.e., providing rough grounding for explainability." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 410, + 286, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 410, + 286, + 529 + ], + "spans": [ + { + "bbox": [ + 49, + 410, + 286, + 529 + ], + "type": "text", + "content": "We pre-train the model on one widely-used medical image-report dataset MIMIC-CXR [31], and rigorously evaluate on the task of disease diagnosis across numerous public benchmarks, e.g., ChestX-ray14 [58], RSNA Pneumonia [51], SIIM-ACR Pneumothorax [1], COVIDx CXR2 [48], COVID Rural [54, 15], and EdemaSeverity [7]. We get state-of-the-art performance on zero-shot classification and grounding on different diseases, spanning different image distributions, with further fine-tuning, our model still exceeds previous models significantly." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 542, + 132, + 555 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 542, + 132, + 555 + ], + "spans": [ + { + "bbox": [ + 49, + 542, + 132, + 555 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 563, + 286, + 694 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 563, + 286, + 694 + ], + "spans": [ + { + "bbox": [ + 49, + 563, + 286, + 694 + ], + "type": "text", + "content": "General Vision-Language Pre-training (VLP) Models. In computer vision, such line of research has gained tremendous success in the recent literature, generally speaking, the developed architectures can either be two-stream [4, 33, 30], i.e., dual encoders, or those based on single-stream methods [35, 9], that favors visual-language fusion. In particular, several works [13, 38, 66] consider considers to combine the commonsense knowledge into the vision-language pre-training, however, in this paper, we focus on medical domain, which is clearly more fine-grained and requires significantly more expertise." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 701, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 701, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 49, + 701, + 286, + 712 + ], + "type": "text", + "content": "Medical Named-Entity-Rcognition (NER) Models. Var" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 308, + 72, + 544, + 204 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 72, + 544, + 204 + ], + "spans": [ + { + "bbox": [ + 308, + 72, + 544, + 204 + ], + "type": "text", + "content": "ious natural language processing (NLP) approaches have been proposed to extract information from radiology reports [49, 28, 44, 52]. These early methods considered only the disease, thus causing information loss. Further state-of-the-art works [29, 61] are proposed to extract relationship between different entities without demand of pre-defined close disease set, retaining most of useful information with high accuracy. In weakly supervision [67] and report generation fields [14], NER methods have shown great impact, and greatly inspired us for more effective vision-language pre-training with medical domain knowledge injected." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 308, + 207, + 544, + 411 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 207, + 544, + 411 + ], + "spans": [ + { + "bbox": [ + 308, + 207, + 544, + 411 + ], + "type": "text", + "content": "Medical Knowledge Enhanced Models. In general NLP, many works considering combining knowledge, e.g., K-BERT [41] while they consider general knowledge more and focuses on language encoding. In medical community, leveraging external medical knowledge to enhance deep learning models is also a quite important topic [62]. Depending the approaches of using medical knowledge, They can be classified into model-based or input-based. In model-based approaches, the authors aim to imitate the radiological or diagnosis practice to design models [34, 23, 57, 26, 45, 21, 12]. While in input-based approaches, the knowledge is treated as an extra input for computing features [65, 63, 53, 11] or to guide the final training loss [8, 27, 37, 39, 43], commonly used in report generation tasks [59, 64, 40, 11, 36]. However, none of these works are targeting on vision-language pre-training in medical domain with image-report." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 308, + 415, + 544, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 415, + 544, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 415, + 544, + 712 + ], + "type": "text", + "content": "Concurrent Works in Medical VLP. Existing medical VLP methods follow the two-stream flow [68, 25, 7, 47, 60, 10], i.e., use contrastive learning and without fusion module, for example, ConVIRT [68] initially proposed to use contrastive loss as a proxy task for aligning the medical scan and corresponding reports, LoVT and GLoRIA then focus on improving the local alignment performance [25, 7]. BioViL notices the language pattern in reports is different from natural texts and re-designs the language model [6]. The recent arxiv preprint, MedCLIP [60], considers leveraging unpaired data to make up data scarcity. The most related to ours is CheXzero [56], which targets at zero-shot diagnosis. Align [10] focuses on leveraging external medical knowledge to improve the performance of VLP model on medical Visual Question Answering (VQA). However, they treat knowledge as an additional loss and we adopt a new training scheme leveraging medical knowledge by aligning entity, instead of raw reports, with images. Despite significant contribution has been made by existing work [68, 25, 7, 47, 60, 56], they still treat medical texts and images as common natural data and do not explicitly leverage the rich prior knowledge from medical domain. In this paper, we consider to incorporate domain knowledge, re-design the pre-training pipeline delicately and target at accurate diagnosis in X-ray scans." + } + ] + } + ], + "index": 8 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 733, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 733, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 733, + 317, + 742 + ], + "type": "text", + "content": "21373" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 85, + 142, + 185 + ], + "blocks": [ + { + "bbox": [ + 50, + 72, + 142, + 83 + ], + "lines": [ + { + "bbox": [ + 50, + 72, + 142, + 83 + ], + "spans": [ + { + "bbox": [ + 50, + 72, + 142, + 83 + ], + "type": "text", + "content": "A. Report Pre-processing" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 50, + 85, + 142, + 185 + ], + "lines": [ + { + "bbox": [ + 50, + 85, + 142, + 185 + ], + "spans": [ + { + "bbox": [ + 50, + 85, + 142, + 185 + ], + "type": "image", + "image_path": "184e46e42002293ec887f663549c937d2195280796d5db9df1c9cdf2a9572e59.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 152, + 86, + 304, + 188 + ], + "blocks": [ + { + "bbox": [ + 147, + 73, + 301, + 84 + ], + "lines": [ + { + "bbox": [ + 147, + 73, + 301, + 84 + ], + "spans": [ + { + "bbox": [ + 147, + 73, + 301, + 84 + ], + "type": "text", + "content": "B. Knowledge-enhanced Triplet Encoding" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 152, + 86, + 304, + 188 + ], + "lines": [ + { + "bbox": [ + 152, + 86, + 304, + 188 + ], + "spans": [ + { + "bbox": [ + 152, + 86, + 304, + 188 + ], + "type": "image", + "image_path": "451617ab1cdd63e7cf8934a4a7fac0f453f4ef445779f596a32b658c20aa624b.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 313, + 85, + 544, + 190 + ], + "blocks": [ + { + "bbox": [ + 313, + 73, + 373, + 84 + ], + "lines": [ + { + "bbox": [ + 313, + 73, + 373, + 84 + ], + "spans": [ + { + "bbox": [ + 313, + 73, + 373, + 84 + ], + "type": "text", + "content": "C. Training Flow" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 313, + 85, + 544, + 190 + ], + "lines": [ + { + "bbox": [ + 313, + 85, + 544, + 190 + ], + "spans": [ + { + "bbox": [ + 313, + 85, + 544, + 190 + ], + "type": "image", + "image_path": "1e1f7ad98701c856502e4577d8ac37167e88115900b73763bd0763e5e9981816.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 200, + 547, + 248 + ], + "lines": [ + { + "bbox": [ + 46, + 200, + 547, + 248 + ], + "spans": [ + { + "bbox": [ + 46, + 200, + 547, + 248 + ], + "type": "text", + "content": "Figure 2: The whole framework of our method. We first pre-process the report into triplets leveraging triplet extraction module. Then we encode the extracted triplets and it is worth emphasizing that we translate the entities into detailed descriptions during encoding, by querying the medical knowledge base. Finally we change the training flow with triplets, i.e., we query a transformer-based fusion module at entity level, which provides more detailed supervision signals." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 254, + 102, + 266 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 254, + 102, + 266 + ], + "spans": [ + { + "bbox": [ + 47, + 254, + 102, + 266 + ], + "type": "text", + "content": "3. Method" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 277, + 287, + 397 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 277, + 287, + 397 + ], + "spans": [ + { + "bbox": [ + 46, + 277, + 287, + 397 + ], + "type": "text", + "content": "In this section, we start by describing the considered problem scenario in Sec. 3.1, followed by our report pre-process operation with triplet extraction in Sec. 3.2. Then we introduce our proposed knowledge-enhanced architecture in Sec. 3.3, including, visual encoder, knowledge-enhanced triplet encoder, and the fusion module for aligning visual-language signals. In Sec. 3.4, we describe the training procedure with the paired image-reports sourced from the daily routine X-ray scans and, in Sec.3.5, we introduce the procedure for inference." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 416, + 153, + 427 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 416, + 153, + 427 + ], + "spans": [ + { + "bbox": [ + 47, + 416, + 153, + 427 + ], + "type": "text", + "content": "3.1. Problem Scenario" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 438, + 287, + 559 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 438, + 287, + 559 + ], + "spans": [ + { + "bbox": [ + 46, + 438, + 287, + 559 + ], + "type": "text", + "content": "Assuming we are given a training set with " + }, + { + "bbox": [ + 46, + 438, + 287, + 559 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 438, + 287, + 559 + ], + "type": "text", + "content": " samples, i.e., " + }, + { + "bbox": [ + 46, + 438, + 287, + 559 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{\\mathrm{train}} = \\{(\\mathcal{X}_1,\\mathcal{T}_1),\\ldots ,(\\mathcal{X}_N,\\mathcal{T}_N)\\}" + }, + { + "bbox": [ + 46, + 438, + 287, + 559 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 438, + 287, + 559 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_i,\\mathcal{T}_i" + }, + { + "bbox": [ + 46, + 438, + 287, + 559 + ], + "type": "text", + "content": " refer to the X-ray image and its corresponding medical report generated in the daily routine scans, respectively, our goal is to train a visual-language model that enables us to diagnose the existence of certain diseases and localize the visual evidence spatially. Specifically, at inference time, we can freely ask the system to identify the likelihood of the patient getting a certain disease (seen or unseen during training):" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 56, + 575, + 287, + 588 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 575, + 287, + 588 + ], + "spans": [ + { + "bbox": [ + 56, + 575, + 287, + 588 + ], + "type": "interline_equation", + "content": "\\hat {s} _ {i}, \\hat {m} _ {i} = \\Phi_ {\\text {f u s i o n}} \\left(\\Phi_ {\\text {v i s u a l}} \\left(\\mathcal {X} _ {i}\\right), \\Phi_ {\\text {t e x t u a l}} ([ \\text {d e s c r i p t i o n} ])\\right), \\tag {1}", + "image_path": "94530f2317728f64b45f53360f813803483a3688100891b1e9c615406e234e38.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{X}_i\\in \\mathbb{R}^{H\\times W\\times 3}" + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "content": " refers to an image sample from the test set, with " + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "inline_equation", + "content": "H,W" + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "content": " denoting height and width respectively. " + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\hat{s}_i\\in [0,1]" + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "content": " refers to the inferred likelihood of the patient having a certain disease indicated by the input description, and " + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\hat{m}_i\\in \\mathbb{R}^{H\\times W\\times 1}" + }, + { + "bbox": [ + 46, + 605, + 287, + 713 + ], + "type": "text", + "content": " denotes a predicted spatial heatmap, with high activation on pixels that potentially provide the visual indication for such disease. In the following section, we will introduce our report pre-process operation with triplet extraction." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 255, + 433, + 267 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 255, + 433, + 267 + ], + "spans": [ + { + "bbox": [ + 306, + 255, + 433, + 267 + ], + "type": "text", + "content": "3.2. Report Pre-processing" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 273, + 545, + 333 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 273, + 545, + 333 + ], + "spans": [ + { + "bbox": [ + 305, + 273, + 545, + 333 + ], + "type": "text", + "content": "To start with, we propose to pre-process medical reports with a Triplet Extraction module by removing the unnecessary complexity from language grammar. Note that, we hereon only consider single sampled image-reports pair " + }, + { + "bbox": [ + 305, + 273, + 545, + 333 + ], + "type": "inline_equation", + "content": "(\\mathcal{X}_i,\\mathcal{T}_i)" + }, + { + "bbox": [ + 305, + 273, + 545, + 333 + ], + "type": "text", + "content": ", and ignore the subscript in notations for simplicity." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 333, + 546, + 548 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 333, + 546, + 548 + ], + "spans": [ + { + "bbox": [ + 304, + 333, + 546, + 548 + ], + "type": "text", + "content": "We condense the original reports with an off-shelf medical Named Entity Recognition (NER) method, namely RadGraph [29, 67], transforming reports into a set of triplets, as shown in Figure 2A. In detail, the medical key words can be extracted and classified as \"entity\" or \"position\" with the NER module. \"Entity\" refers to some clinical observations, like \"Opacity\". \"Position\" refers to the anatomical body part that occurs in a radiology report, like \"right lower lobe\". Besides, the NER module will also provide an \"exist\" label to conclude whether an entity is claimed to be exist, absent or uncertain in reports. Based on this, we can use a set of triplets, i.e., {entity, position, exist}, to reformulate the sentence in reports, for example, the triplet {Opacity, Right lower lobe, True} represents \"It is true that there is opacity located at right lower lobe\". Note that, the triplets with a specific \"position\" are not always termed as True in \"exist\" as radiologists may point out entities absent at some specific position." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 548, + 545, + 596 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 548, + 545, + 596 + ], + "spans": [ + { + "bbox": [ + 305, + 548, + 545, + 596 + ], + "type": "text", + "content": "Therefore, given a report " + }, + { + "bbox": [ + 305, + 548, + 545, + 596 + ], + "type": "inline_equation", + "content": "\\mathcal{T}" + }, + { + "bbox": [ + 305, + 548, + 545, + 596 + ], + "type": "text", + "content": " with multiple sentences, " + }, + { + "bbox": [ + 305, + 548, + 545, + 596 + ], + "type": "inline_equation", + "content": "\\mathcal{T} = \\{s_1,s_2,\\dots ,s_M\\}" + }, + { + "bbox": [ + 305, + 548, + 545, + 596 + ], + "type": "text", + "content": ", the extraction module independently operates on each of the sentences, and construct a number of triplets from the report:" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 318, + 605, + 545, + 618 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 318, + 605, + 545, + 618 + ], + "spans": [ + { + "bbox": [ + 318, + 605, + 545, + 618 + ], + "type": "interline_equation", + "content": "\\Phi_ {\\mathrm {e x}} \\left(s _ {j}\\right) = \\left\\{\\text {e n t i t y} _ {n}, \\text {p o s i t i o n} _ {n}, \\text {e x i s t} _ {n} \\right\\}, n \\in [ 0, t _ {j} ], \\tag {2}", + "image_path": "ee0bdbf181debc30d0ce134f8f8ced740efb0bb8e2d08a24898915e5d42aa73f.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 626, + 545, + 674 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 626, + 545, + 674 + ], + "spans": [ + { + "bbox": [ + 304, + 626, + 545, + 674 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 626, + 545, + 674 + ], + "type": "inline_equation", + "content": "t_j" + }, + { + "bbox": [ + 304, + 626, + 545, + 674 + ], + "type": "text", + "content": " represents the total number of entities contained in one sentence, with " + }, + { + "bbox": [ + 304, + 626, + 545, + 674 + ], + "type": "inline_equation", + "content": "n = 0" + }, + { + "bbox": [ + 304, + 626, + 545, + 674 + ], + "type": "text", + "content": " indicating the special case that there is no valid entity. After the triplet extraction, each report is equal to a set of triplets." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "content": "Discussion. In contrast to natural texts, information in medical reports tends to be more condensed, with radiologists pointing out the existence of abnormality and their positions" + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "21374" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 156 + ], + "type": "text", + "content": "in the image. Meanwhile, medical terminologies tend to be professional, and within certain vocabulary (mostly listed in UMLS [5]), specially designed NER methods [29] demonstrate great performance on reports. Therefore, adopting the Triplet Extraction operation in medical VLP can avoid unnecessary complexity from understanding grammar, while still retaining the useful information in reports." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 166, + 129, + 178 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 166, + 129, + 178 + ], + "spans": [ + { + "bbox": [ + 47, + 166, + 129, + 178 + ], + "type": "text", + "content": "3.3. Architecture" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 185, + 287, + 233 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 185, + 287, + 233 + ], + "spans": [ + { + "bbox": [ + 46, + 185, + 287, + 233 + ], + "type": "text", + "content": "In this section, we detail our proposed framework, consisting of three components, namely, visual encoding, knowledge-enhanced triplet encoding, and fusion module, as shown in Fig. 2B and Fig. 2C." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 251, + 151, + 264 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 251, + 151, + 264 + ], + "spans": [ + { + "bbox": [ + 47, + 251, + 151, + 264 + ], + "type": "text", + "content": "3.3.1 Visual Encoding" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 271, + 287, + 296 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 271, + 287, + 296 + ], + "spans": [ + { + "bbox": [ + 46, + 271, + 287, + 296 + ], + "type": "text", + "content": "Given an X-ray image scan " + }, + { + "bbox": [ + 46, + 271, + 287, + 296 + ], + "type": "inline_equation", + "content": "\\mathcal{X} \\in \\mathbb{R}^{H \\times W \\times 3}" + }, + { + "bbox": [ + 46, + 271, + 287, + 296 + ], + "type": "text", + "content": ", we can compute the features with a visual backbone:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 110, + 306, + 287, + 321 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 306, + 287, + 321 + ], + "spans": [ + { + "bbox": [ + 110, + 306, + 287, + 321 + ], + "type": "interline_equation", + "content": "\\mathcal {V} = \\Phi_ {\\text {v i s u a l}} (\\mathcal {X}) \\in \\mathbb {R} ^ {h \\times w \\times d}, \\tag {3}", + "image_path": "28a23da7c2b1885f549641f128192461dee58d0f5de927be6663358b995d2cc0.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 331, + 289, + 403 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 331, + 289, + 403 + ], + "spans": [ + { + "bbox": [ + 46, + 331, + 289, + 403 + ], + "type": "inline_equation", + "content": "h, w, d" + }, + { + "bbox": [ + 46, + 331, + 289, + 403 + ], + "type": "text", + "content": " refer to the height, width, and feature dimension of the output, in our case, we adopt ResNet-50 as the visual backbone, and take the output from the 4th residual block. Note that, we make the architectural choice for fair comparison with existing work [68, 47, 25, 6], while other visual backbones, e.g., ViT [17], can equally be applied." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 422, + 247, + 434 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 422, + 247, + 434 + ], + "spans": [ + { + "bbox": [ + 47, + 422, + 247, + 434 + ], + "type": "text", + "content": "3.3.2 Knowledge-enhanced Triplet Encoding" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 442, + 287, + 478 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 442, + 287, + 478 + ], + "spans": [ + { + "bbox": [ + 46, + 442, + 287, + 478 + ], + "type": "text", + "content": "The goal of this module is to encode the triplets extracted from reports by incorporating medical domain knowledge as shown in Fig.2B." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 479, + 289, + 684 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 479, + 289, + 684 + ], + "spans": [ + { + "bbox": [ + 46, + 479, + 289, + 684 + ], + "type": "text", + "content": "Given a triplet as " + }, + { + "bbox": [ + 46, + 479, + 289, + 684 + ], + "type": "inline_equation", + "content": "\\{\\text{entity}, \\text{position}, \\text{exist}\\}" + }, + { + "bbox": [ + 46, + 479, + 289, + 684 + ], + "type": "text", + "content": ", it is easy to code the \"exist\" as it only has three outcomes. We use " + }, + { + "bbox": [ + 46, + 479, + 289, + 684 + ], + "type": "inline_equation", + "content": "l \\in \\{0, 1, -1\\}" + }, + { + "bbox": [ + 46, + 479, + 289, + 684 + ], + "type": "text", + "content": " tockenize it, 1 for True, 0 for False, -1 for uncertain. For the \"entity\" words, we translate them into detailed descriptions by querying some easy-access medical knowledge bases [12], e.g., Description([“Pneumonia”]) = \"It is a condition of the lung primarily ... present with opacities and pleural effusion ...\". Despite its simplicity, converting the entities into descriptions is crucial for more reliable and zero-shot diagnosis, as it further decomposes the professional medical entities into basic attributes that are shared by different diseases, encouraging the model to capture a deep understanding of the visual evidence. For the \"position\" words, we use a prompt as \"It is located at " + }, + { + "bbox": [ + 46, + 479, + 289, + 684 + ], + "type": "inline_equation", + "content": "\\{\\text{position}\\}" + }, + { + "bbox": [ + 46, + 479, + 289, + 684 + ], + "type": "text", + "content": "\" to form a sentence. Finally, we use ClinicalBERT [3] as a pre-trained text encoder, to compute the embedding for the \"entity\" and \"position\", and then adopt a linear MLP to" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 72, + 491, + 84 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 491, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 491, + 84 + ], + "type": "text", + "content": "project the embedding to desired dimensions:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 321, + 93, + 545, + 107 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 321, + 93, + 545, + 107 + ], + "spans": [ + { + "bbox": [ + 321, + 93, + 545, + 107 + ], + "type": "interline_equation", + "content": "e = \\Phi_ {\\text {t e x t u a l}} (\\text {D e s c r i p t i o n} (\\{\\text {e n t i t y} \\})) \\in \\mathbb {R} ^ {d}, \\tag {4}", + "image_path": "5652af5cd1c8dfeb01e7b87397430ee0cf0278cf9988dd20781c1c07724a617b.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 321, + 110, + 545, + 125 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 321, + 110, + 545, + 125 + ], + "spans": [ + { + "bbox": [ + 321, + 110, + 545, + 125 + ], + "type": "interline_equation", + "content": "p = \\Phi_ {\\text {t e x t u a l}} \\left(\" \\text {I t i s l o c a t e d a t} \\{\\text {p o s i t i o n} \\}\\right) \\in \\mathbb {R} ^ {d ^ {\\prime}}. \\tag {5}", + "image_path": "8767b3d4acd631745490dde1a506dcc5bc7291685e8105ac5ae7becd66ea03af.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 134, + 510, + 147 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 134, + 510, + 147 + ], + "spans": [ + { + "bbox": [ + 306, + 134, + 510, + 147 + ], + "type": "text", + "content": "Each triplet has now been embedded into " + }, + { + "bbox": [ + 306, + 134, + 510, + 147 + ], + "type": "inline_equation", + "content": "\\{e,p,l\\}" + }, + { + "bbox": [ + 306, + 134, + 510, + 147 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 149, + 545, + 245 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 149, + 545, + 245 + ], + "spans": [ + { + "bbox": [ + 305, + 149, + 545, + 245 + ], + "type": "text", + "content": "Discussion. The extracted entities are medical terminologies that are only understandable to audiences with a medical background, while enriching them with detailed descriptions helps the model to capture a deep understanding of visual evidence for diseases. Such patterns can be generalized across diseases, as many attribute descriptions tend to be shared, enabling the model to build implicit relationships on seen classes and understand descriptions for unseen ones." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 262, + 404, + 273 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 262, + 404, + 273 + ], + "spans": [ + { + "bbox": [ + 306, + 262, + 404, + 273 + ], + "type": "text", + "content": "3.3.3 Fusion Module" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 281, + 545, + 364 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 281, + 545, + 364 + ], + "spans": [ + { + "bbox": [ + 305, + 281, + 545, + 364 + ], + "type": "text", + "content": "With the triplets from reports, we can supervise the model on the entity level instead of the entire report level. The \"position\" and \"exist\" parts in triplets can be naturally seen as more fine-grained supervision labels. Specifically, we adopt a Transformer-based architecture, use the embedding of entities as query, iteratively attending the image embeddings, and output exist and position predictions of entities." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "spans": [ + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "text", + "content": "In detail, we select the top " + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "inline_equation", + "content": "|Q|" + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "text", + "content": " most commonly appearing entities' embeddings in all training reports, to form an entity query set " + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "inline_equation", + "content": "Q = \\{e_1, e_2, \\dots, e_{|Q|}\\}" + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "text", + "content": ". The details of the entity query set is provided in the supplementary material (Sec. A). Then " + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "text", + "content": " will be passed into a fusion module with the image representation " + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "inline_equation", + "content": "\\mathcal{V}" + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "text", + "content": " for alignment. The fusion module consists of multiple Transformer Decoder layers, with " + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "text", + "content": " as Query, and " + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "inline_equation", + "content": "\\mathcal{V}" + }, + { + "bbox": [ + 305, + 365, + 545, + 484 + ], + "type": "text", + "content": " as Key and Value. The outputs are further fed into two MLPs, independently infer the existence of the entity and the entity's position:" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 367, + 495, + 545, + 509 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 367, + 495, + 545, + 509 + ], + "spans": [ + { + "bbox": [ + 367, + 495, + 545, + 509 + ], + "type": "interline_equation", + "content": "\\left\\{\\hat {s}, \\hat {p}, \\hat {m} \\right\\} = \\Phi_ {\\text {f u s i o n}} (\\mathcal {V}, Q), \\tag {6}", + "image_path": "093fa55abec9c88f5cd30195c21d33286c209cd3bdc57bdf633750f64e559f18.jpg" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 517, + 547, + 615 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 517, + 547, + 615 + ], + "spans": [ + { + "bbox": [ + 304, + 517, + 547, + 615 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 517, + 547, + 615 + ], + "type": "inline_equation", + "content": "\\hat{s} \\in \\mathbb{R}^{|Q|}" + }, + { + "bbox": [ + 304, + 517, + 547, + 615 + ], + "type": "text", + "content": " represents the existence prediction for each entity query, and " + }, + { + "bbox": [ + 304, + 517, + 547, + 615 + ], + "type": "inline_equation", + "content": "\\hat{p} \\in \\mathbb{R}^{|Q| \\times d'}" + }, + { + "bbox": [ + 304, + 517, + 547, + 615 + ], + "type": "text", + "content": " represents the predicted position for all entities. Note that, " + }, + { + "bbox": [ + 304, + 517, + 547, + 615 + ], + "type": "inline_equation", + "content": "\\hat{m} \\in \\mathbb{R}^{H \\times W}" + }, + { + "bbox": [ + 304, + 517, + 547, + 615 + ], + "type": "text", + "content": " denotes the average of the cross-attention maps sourced from Transformer layers and is up-sampled to the size of input image with nearest interpolation. " + }, + { + "bbox": [ + 304, + 517, + 547, + 615 + ], + "type": "inline_equation", + "content": "\\hat{m}" + }, + { + "bbox": [ + 304, + 517, + 547, + 615 + ], + "type": "text", + "content": " is used for grounding at inference, as it naturally acts as a segmentation heatmap. During training, we will not directly calculate any loss on it." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 617, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 547, + 713 + ], + "type": "text", + "content": "Discussion. Adopting Transformer decoder enables to compute correspondences between entities and images at patch-level. Consequently, image features " + }, + { + "bbox": [ + 304, + 617, + 547, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{V}" + }, + { + "bbox": [ + 304, + 617, + 547, + 713 + ], + "type": "text", + "content": " are more suitable for downstream segmentation tasks and the average of cross-attention maps in each layers can be used directly for zero-shot grounding, providing explainable for diagnosis. Besides, the default self-attention on queries in Transformer structure can also build relationships across entities." + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 47, + 693, + 271, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 693, + 271, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 693, + 271, + 713 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 47, + 693, + 271, + 713 + ], + "type": "text", + "content": "Wikipedia https://en.wikipedia.org/wiki/ " + }, + { + "bbox": [ + 47, + 693, + 271, + 713 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 47, + 693, + 271, + 713 + ], + "type": "text", + "content": "UMLS [5] https://www.nlm.nih.gov/research/uml5/" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "21375" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 111, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 111, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 111, + 85 + ], + "type": "text", + "content": "3.4. Training" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "spans": [ + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "content": "Given a set of encoded triplets " + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "inline_equation", + "content": "\\{e,p,l\\}" + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "content": " extracted from the pairing reports " + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "inline_equation", + "content": "\\mathcal{T}" + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "content": ", we can compute training loss on the output of fusion module. For the existence prediction " + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "inline_equation", + "content": "\\hat{s}" + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "content": ", we use binary cross-entropy with the corresponding \"exist\" labels " + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "content": ", and if " + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "content": " is " + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "inline_equation", + "content": "-1" + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "content": " we just pass this label, denoted as " + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{cls}}" + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "content": ". To supervise the position prediction for each entity query, we adopt contrastive learning. We form a position set with top " + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "inline_equation", + "content": "|P|" + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "content": " common position embeddings as a position set, " + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "inline_equation", + "content": "P = \\{p_{1},p_{2},\\dots ,p_{|P|}\\}" + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "content": ", randomly sample " + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "content": " negative position embeddings from it, and use the corresponding position embedding " + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 46, + 89, + 289, + 224 + ], + "type": "text", + "content": " from triplets as positive:" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 62, + 231, + 287, + 266 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 231, + 287, + 266 + ], + "spans": [ + { + "bbox": [ + 62, + 231, + 287, + 266 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {l o c}} = - \\frac {1}{| Q |} \\sum_ {k = 1} ^ {| Q |} \\frac {e ^ {\\langle \\hat {p} _ {k} , p _ {k} \\rangle}}{e ^ {\\langle \\hat {p} _ {k} , p _ {k} \\rangle} + \\sum_ {u = 1} ^ {M} e ^ {\\langle \\hat {p} _ {k} , P _ {\\mathcal {I} (k , u)} \\rangle}}, \\tag {7}", + "image_path": "7f9130ce24a1b9ac9cd4cdff45f6f92b06d7dcc01cba0b2abdf70bc2af5891de.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 273, + 287, + 345 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 273, + 287, + 345 + ], + "spans": [ + { + "bbox": [ + 47, + 273, + 287, + 345 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 273, + 287, + 345 + ], + "type": "inline_equation", + "content": "\\langle \\cdot, \\cdot \\rangle" + }, + { + "bbox": [ + 47, + 273, + 287, + 345 + ], + "type": "text", + "content": " represents the inner product of two vectors and " + }, + { + "bbox": [ + 47, + 273, + 287, + 345 + ], + "type": "inline_equation", + "content": "\\mathcal{I}(\\cdot, \\cdot)" + }, + { + "bbox": [ + 47, + 273, + 287, + 345 + ], + "type": "text", + "content": " is a random index sampling function. The position embeddings are un-normalized in calculation. Note that, some entities may not be mentioned in the report and thus, we can not find corresponding labels in triplets. We simply ignore the corresponding predictions while computing loss." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 59, + 346, + 205, + 357 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 346, + 205, + 357 + ], + "spans": [ + { + "bbox": [ + 59, + 346, + 205, + 357 + ], + "type": "text", + "content": "The final loss is the sum of the two:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 115, + 367, + 287, + 380 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 115, + 367, + 287, + 380 + ], + "spans": [ + { + "bbox": [ + 115, + 367, + 287, + 380 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {t o t a l}} = \\alpha_ {1} \\mathcal {L} _ {\\text {l o c}} + \\alpha_ {2} \\mathcal {L} _ {\\text {c l s}}, \\tag {8}", + "image_path": "84027fbd1125fed1ae36623ec38d0e1fccc92d4a82fb24bf90c939f50d047344.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 388, + 287, + 413 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 388, + 287, + 413 + ], + "spans": [ + { + "bbox": [ + 47, + 388, + 287, + 413 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 388, + 287, + 413 + ], + "type": "inline_equation", + "content": "\\alpha_{1},\\alpha_{2}" + }, + { + "bbox": [ + 47, + 388, + 287, + 413 + ], + "type": "text", + "content": " refer to two hyper-parameters controlling the ratio of the two losses, and we set them to be 1.0 by default." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 417, + 287, + 478 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 417, + 287, + 478 + ], + "spans": [ + { + "bbox": [ + 47, + 417, + 287, + 478 + ], + "type": "text", + "content": "Discussion. In contrast to the existing approaches [68] that align images with entire reports, our training paradigm with triplets provides supervision at a more fine-grained entity level, rather than the global alignment between image and reports as has often done in existing approaches." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 485, + 115, + 496 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 485, + 115, + 496 + ], + "spans": [ + { + "bbox": [ + 47, + 485, + 115, + 496 + ], + "type": "text", + "content": "3.5. Inference" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "type": "text", + "content": "At inference time, given a test image, we can directly infer the existence of certain entities/disease, and ground their visual evidence. In particular, for the entities that have appeared in the entity query set " + }, + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "type": "text", + "content": ", we simply adopt the corresponding elements from " + }, + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "type": "text", + "content": ", while for those unseen ones, we replace the entity with a brief description provided by the user, and treat it as an extra query added to entity query set " + }, + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "type": "inline_equation", + "content": "Q" + }, + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "type": "text", + "content": ", resembling zero-shot inference. The existence output " + }, + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "type": "inline_equation", + "content": "\\hat{s}" + }, + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "type": "text", + "content": " can be directly applied for classification, the average cross-attention " + }, + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "type": "inline_equation", + "content": "\\hat{m}" + }, + { + "bbox": [ + 46, + 503, + 287, + 635 + ], + "type": "text", + "content": " between the target entity and the visual features are used for grounding." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 646, + 124, + 659 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 646, + 124, + 659 + ], + "spans": [ + { + "bbox": [ + 47, + 646, + 124, + 659 + ], + "type": "text", + "content": "4. Experiment" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 665, + 287, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 665, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 47, + 665, + 287, + 712 + ], + "type": "text", + "content": "In this section, we start by introducing the dataset used for experiments, e.g., pre-training, and various downstream datasets. Then we describe the implementation details and the considered baselines." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 72, + 424, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 424, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 424, + 84 + ], + "type": "text", + "content": "4.1. Pre-training Dataset" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 89, + 547, + 139 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 89, + 547, + 139 + ], + "spans": [ + { + "bbox": [ + 305, + 89, + 547, + 139 + ], + "type": "text", + "content": "MIMIC-CXR v2 [31, 22] consists of over 227k studies of paired image-report data, they are sourced from 65,379 patients at different scanning. Each study can have one or two images (different scan views), totaling 377,110 images." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 144, + 476, + 156 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 144, + 476, + 156 + ], + "spans": [ + { + "bbox": [ + 306, + 144, + 476, + 156 + ], + "type": "text", + "content": "4.2. Datasets for Downstream Tasks" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 163, + 546, + 222 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 163, + 546, + 222 + ], + "spans": [ + { + "bbox": [ + 305, + 163, + 546, + 222 + ], + "type": "text", + "content": "ChestX-ray14 [58] contains 112,120 frontal-view X-ray images of 30,805 unique patients, collected from the year of 1992 to 2015 by NIH(National Institutes of Health), with labels of 14 common diseases provided. We split the dataset into " + }, + { + "bbox": [ + 305, + 163, + 546, + 222 + ], + "type": "inline_equation", + "content": "0.8 / 0.1 / 0.1" + }, + { + "bbox": [ + 305, + 163, + 546, + 222 + ], + "type": "text", + "content": " for train-valid/test." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 225, + 547, + 297 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 225, + 547, + 297 + ], + "spans": [ + { + "bbox": [ + 305, + 225, + 547, + 297 + ], + "type": "text", + "content": "RSNA Pneumonia [51] contains more than 260k frontal-view chest X-rays with corresponding pneumonia opacity masks collected by RSNA (Radiological Society of North America). Commonly, it is treated as a classification tasks [25, 6]. We split the dataset into " + }, + { + "bbox": [ + 305, + 225, + 547, + 297 + ], + "type": "inline_equation", + "content": "0.6 / 0.2 / 0.2" + }, + { + "bbox": [ + 305, + 225, + 547, + 297 + ], + "type": "text", + "content": " for train-valid/test." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 305, + 300, + 546, + 384 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 300, + 546, + 384 + ], + "spans": [ + { + "bbox": [ + 305, + 300, + 546, + 384 + ], + "type": "text", + "content": "SIIM-ACR Pneumothorax [1] contains more than 12k frontal-view chest X-rays with pneumothorax masks collected by SIIM-ACR (Society for Imaging Informatics in Medicine and American College of Radiology). Similarly to RSNA Pneumonia dataset, it can be both used as classification and segmentation tasks. We split the dataset into 0.6/0.2/0.2 for train-valid/test." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 386, + 546, + 483 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 386, + 546, + 483 + ], + "spans": [ + { + "bbox": [ + 305, + 386, + 546, + 483 + ], + "type": "text", + "content": "COVIDx CXR-2 [48] and COVID Rural [54, 15] aim to evaluate on diagnosing COVID-19. COVIDx CXR-3 contains 29,986 images from 16,648 patients with COVID-19 classification labels. We use it as a classification dataset and split it into " + }, + { + "bbox": [ + 305, + 386, + 546, + 483 + ], + "type": "inline_equation", + "content": "0.7 / 0.2 / 0.1" + }, + { + "bbox": [ + 305, + 386, + 546, + 483 + ], + "type": "text", + "content": " for train-valid/test. Additionally, we use COVID Rural dataset for COVID-19 segmentation. It contains more than 200 chest X-rays with segmentation masks, and we split it into " + }, + { + "bbox": [ + 305, + 386, + 546, + 483 + ], + "type": "inline_equation", + "content": "0.6 / 0.2 / 0.2" + }, + { + "bbox": [ + 305, + 386, + 546, + 483 + ], + "type": "text", + "content": " for train-valid/test." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 305, + 485, + 547, + 570 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 485, + 547, + 570 + ], + "spans": [ + { + "bbox": [ + 305, + 485, + 547, + 570 + ], + "type": "text", + "content": "Edema Severity [7] contains 6,524 examples from MIMIC-CXR with pulmonary edema severity labels (0 to 3, increasing severity) extracted from the radiology reports. Of these, 141 radiologists were examined by radiologists, and consensus was reached on severity level. It can be seen as a typical fine-grained classification task. We split the dataset into " + }, + { + "bbox": [ + 305, + 485, + 547, + 570 + ], + "type": "inline_equation", + "content": "0.6 / 0.2 / 0.2" + }, + { + "bbox": [ + 305, + 485, + 547, + 570 + ], + "type": "text", + "content": " for train-valid/test." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 575, + 404, + 588 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 575, + 404, + 588 + ], + "spans": [ + { + "bbox": [ + 306, + 575, + 404, + 588 + ], + "type": "text", + "content": "4.3. Implementation" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 305, + 594, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 594, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 305, + 594, + 547, + 714 + ], + "type": "text", + "content": "This section describes the implementation for architectures. In Pre-training, the triplets extraction module and text encoders used in triplets encoding are all fixed, while the visual encoder and fusion module are trained end-to-end on the image-text pairs. In Fine-tuning, we adopt ResNet50 [24] initialized with image encoder for classification, and ResUNet [16] initialize its encoder with our pretrained image encoder for segmentation. More details about exact values of different parameters and training progress can be found in supplementary material (Sec. B)" + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "21376" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 72, + 71, + 519, + 153 + ], + "blocks": [ + { + "bbox": [ + 72, + 71, + 519, + 153 + ], + "lines": [ + { + "bbox": [ + 72, + 71, + 519, + 153 + ], + "spans": [ + { + "bbox": [ + 72, + 71, + 519, + 153 + ], + "type": "table", + "html": "
Dataset MethodsRSNA PneumoniaSIIM-ACR PneumothoraxChestX-ray14
AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑
ConVIRT [68]0.80420.58420.76110.64310.43290.57000.61010.16280.7102
GLoRIA [25]0.71450.49010.71290.53420.38230.40470.66100.17320.7700
BioViL [6]0.82800.58330.76690.70790.48550.69090.69120.19310.7916
CheXzero [56]0.85790.62110.79420.68790.47040.54660.72960.21410.8278
Ours0.86940.63420.80020.89240.68330.84280.76760.25250.8619
", + "image_path": "94e0e3b58e16fc02e2731faa5945743bda758597494b5f18794a11cc6e3dee7e.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 53, + 191, + 347, + 275 + ], + "blocks": [ + { + "bbox": [ + 46, + 156, + 547, + 180 + ], + "lines": [ + { + "bbox": [ + 46, + 156, + 547, + 180 + ], + "spans": [ + { + "bbox": [ + 46, + 156, + 547, + 180 + ], + "type": "text", + "content": "Table 1: Comparison with other state-of-the-art methods on zero-shot classification task. AUC, F1 and ACC scores are reported. For ChestX-ray14, the metrics all refer to the macro average on the 14 diseases." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 53, + 191, + 347, + 275 + ], + "lines": [ + { + "bbox": [ + 53, + 191, + 347, + 275 + ], + "spans": [ + { + "bbox": [ + 53, + 191, + 347, + 275 + ], + "type": "table", + "html": "
Prompt Type MethodsDirect Covid-19Covid-19 Description
AUC↑F1↑ACC↑AUC↑F1↑ACC↑
ConVIRT [68]0.61590.70570.61130.52080.69020.5266
GLoRIA [25]0.63190.69380.57100.66590.70070.6083
BioViL [6]0.61370.69580.54610.53820.69100.5375
CheXzero [56]0.64620.73690.66290.66670.64000.6578
Ours0.65610.70660.59170.73960.76700.7006
", + "image_path": "616b8d4a6206eb01043de702736db618cb27831de1ae985d3e9dd83f55443560.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 351, + 192, + 545, + 276 + ], + "lines": [ + { + "bbox": [ + 351, + 192, + 545, + 276 + ], + "spans": [ + { + "bbox": [ + 351, + 192, + 545, + 276 + ], + "type": "text", + "content": "Table 2: Comparison with other state-of-the-art methods on zero-shot Covid-19 classification task. AUC, F1 and ACC scores are reported. \"Direct Covid-19\" refers to directly use \"Covid-19\" to construct the prompt sentence while \"Covid-19 Description\" refers to replace the name \"Covid-19\" with its description." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 47, + 286, + 113, + 298 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 286, + 113, + 298 + ], + "spans": [ + { + "bbox": [ + 47, + 286, + 113, + 298 + ], + "type": "text", + "content": "4.4. Baselines" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 304, + 288, + 437 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 304, + 288, + 437 + ], + "spans": [ + { + "bbox": [ + 46, + 304, + 288, + 437 + ], + "type": "text", + "content": "We compare with various existing state-of-the-art medical image-text pre-train methods, namely, ConVIRT [68], GLoRIA [25], BioViL [6] and CheXzero [56]. Since ConVIRT and GLoRIA are pre-trained on an in-house dataset, we re-train their models on MIMIC-CXR dataset for fair comparison. For BioViL, we use the officially released models by the authors. For zero-shot setting, we use the prompt as mentioned by BioViL [6] and compare to the very recent method (CheXzero [56]) that has shown to have better zero-shot diagnosis ability than radiologists. For finetuning, we all use the same setting as described in Sec. 4.3." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 444, + 106, + 455 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 444, + 106, + 455 + ], + "spans": [ + { + "bbox": [ + 47, + 444, + 106, + 455 + ], + "type": "text", + "content": "4.5. Metrics" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 464, + 287, + 525 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 464, + 287, + 525 + ], + "spans": [ + { + "bbox": [ + 46, + 464, + 287, + 525 + ], + "type": "text", + "content": "AUC, F1 and ACC are measured for classification tasks. F1 comprehensively measures the recall and precision of the model, and ACC is the short of Accuracy. The final binary prediction threshold is chosen to maximise the F1 score. The ACC score is also calculated under this threshold." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 528, + 287, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 528, + 287, + 601 + ], + "spans": [ + { + "bbox": [ + 46, + 528, + 287, + 601 + ], + "type": "text", + "content": "Pointing Game is used for evaluating the grounding performance. In specific, we extract the region with max response in the output heat-map, for one instance, if the region hit the ground-truth mask, it is considered a positive prediction, otherwise negative. Finally, accuracy can be calculated as the pointing game score." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 602, + 287, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 602, + 287, + 651 + ], + "spans": [ + { + "bbox": [ + 46, + 602, + 287, + 651 + ], + "type": "text", + "content": "Dice and IOU are commonly used for segmentation tasks. For zero-shot segmentation, we search the segmentation threshold with 0.01 interval for all methods, and report the maximal Dice score for each model." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "type": "text", + "content": "Precision and Recall refer to the detection Precision and Recall. For medical, it is important that lesions are detected even without fine segmentation. Additionally, in some hard cases, especially for the zero-shot setting, Dice and IOU may be too strict to reflect the performance differ" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 287, + 545, + 311 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 287, + 545, + 311 + ], + "spans": [ + { + "bbox": [ + 305, + 287, + 545, + 311 + ], + "type": "text", + "content": "ence. Precision and recall scores can compensate for these. We choose the IOU threshold as 0.1 to calculate the scores." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 324, + 359, + 337 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 324, + 359, + 337 + ], + "spans": [ + { + "bbox": [ + 306, + 324, + 359, + 337 + ], + "type": "text", + "content": "5. Results" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 345, + 545, + 489 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 345, + 545, + 489 + ], + "spans": [ + { + "bbox": [ + 304, + 345, + 545, + 489 + ], + "type": "text", + "content": "In this section, we will report the experimental results. In general, we split the results into two parts: zero-shot setting and fine-tuning setting. In the zero-shot case (Sec. 5.1), we carry out the ablation study and compare it with the other SOTA image-text pre-train methods. We mainly consider classification and segmentation tasks; in the fine-tuning case (Sec. 5.2), we evaluate the model's transferability by fine-tuning the model with " + }, + { + "bbox": [ + 304, + 345, + 545, + 489 + ], + "type": "inline_equation", + "content": "1\\%" + }, + { + "bbox": [ + 304, + 345, + 545, + 489 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 345, + 545, + 489 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 304, + 345, + 545, + 489 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 345, + 545, + 489 + ], + "type": "inline_equation", + "content": "100\\%" + }, + { + "bbox": [ + 304, + 345, + 545, + 489 + ], + "type": "text", + "content": " data portion. Additionally, we also add a disease grading downstream task, which can be seen as a fine-grade classification task, showing that our pre-trained model can be transferred to the downstream tasks at ease." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 498, + 427, + 510 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 498, + 427, + 510 + ], + "spans": [ + { + "bbox": [ + 306, + 498, + 427, + 510 + ], + "type": "text", + "content": "5.1. Zero-shot Evaluation" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 518, + 545, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 518, + 545, + 602 + ], + "spans": [ + { + "bbox": [ + 304, + 518, + 545, + 602 + ], + "type": "text", + "content": "In this section, we compare our method with other state-of-the-art methods under zero-shot setting, on classification and grounding. Due to the space limitation, we include the entire ablation study in the supplementary material (Sec. C), referring to it for more details and analysis, and all comparisons here are made using our best model with position contrastive loss and entity description encoder." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 621, + 397, + 632 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 621, + 397, + 632 + ], + "spans": [ + { + "bbox": [ + 306, + 621, + 397, + 632 + ], + "type": "text", + "content": "5.1.1 Classification" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 641, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 545, + 713 + ], + "type": "text", + "content": "Seen Diseases. As shown in Tab. 1, we compare with existing methods on three widely-used datasets, demonstrating consistent performance improvement. Specifically, on pneumonia and pneumothorax datasets, despite the images being collected by different clinics with different diseases, our model improves the AUC score from 0.83 to 0.87 on" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "21377" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 70, + 315, + 125 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 315, + 125 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 315, + 125 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 315, + 125 + ], + "type": "table", + "html": "
MethodsPointing Game↑Recall↑Precision↑IoU↑Dice↑
GLoRIA [25]0.76070.83300.16210.21820.3468
BioViL [6]0.83420.85210.50340.30290.4386
Ours0.87210.86610.64200.31720.4649
", + "image_path": "09923556a4426d48dca8851532d90c4f06edd2580c15686400e5a85b1c718236.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 332, + 70, + 534, + 125 + ], + "blocks": [ + { + "bbox": [ + 119, + 129, + 262, + 140 + ], + "lines": [ + { + "bbox": [ + 119, + 129, + 262, + 140 + ], + "spans": [ + { + "bbox": [ + 119, + 129, + 262, + 140 + ], + "type": "text", + "content": "(a) Zero-shot grounding on Pneumonia" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 332, + 70, + 534, + 125 + ], + "lines": [ + { + "bbox": [ + 332, + 70, + 534, + 125 + ], + "spans": [ + { + "bbox": [ + 332, + 70, + 534, + 125 + ], + "type": "table", + "html": "
MethodsPointing Game↑Recall↑Precision↑
GLoRIA [25]0.06510.23770.0585
BioViL [6]0.02520.19630.1429
Ours0.19750.35620.1940
", + "image_path": "10ef62940d592a119cbca004fa33d052315954cf23d7514cee5ae7d1e9ff9a5f.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 82, + 216, + 511, + 280 + ], + "blocks": [ + { + "bbox": [ + 359, + 129, + 515, + 140 + ], + "lines": [ + { + "bbox": [ + 359, + 129, + 515, + 140 + ], + "spans": [ + { + "bbox": [ + 359, + 129, + 515, + 140 + ], + "type": "text", + "content": "(b) Zero-shot grounding on Pneumothorax" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 45, + 144, + 547, + 204 + ], + "lines": [ + { + "bbox": [ + 45, + 144, + 547, + 204 + ], + "spans": [ + { + "bbox": [ + 45, + 144, + 547, + 204 + ], + "type": "text", + "content": "Table 3: Comparison with other state-of-the-art methods on zero-shot region grounding tasks. (a) shows the results on RSNA Pneumonia dataset. (b) shows the results on SIIM-ACR Pneumothorax dataset. The pneumothorax region tends to be thin and narrow and much more challenging for grounding, we thus only consider pointing game, recall, and precision. Our method can achieve better performance on different metrics, especially on the pointing game score. ConVIRT and CheXzero can not realize this function." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 82, + 216, + 511, + 280 + ], + "lines": [ + { + "bbox": [ + 82, + 216, + 511, + 280 + ], + "spans": [ + { + "bbox": [ + 82, + 216, + 511, + 280 + ], + "type": "table", + "html": "
Prompt Type MethodsDirect COVID-19Covid-19 Description
Pointing Game↑Recall↑Precision↑IoU↑Dice↑Pointing Game↑AR↑AP↑IoU↑Dice↑
GLoRIA [25]0.03640.29060.10730.06450.11410.27270.28210.13360.05960.1075
BioViL [6]0.40000.25640.27030.11980.19670.18180.23930.16370.08610.1427
Ours0.18180.18800.14970.07470.12890.58180.52140.49590.13730.2278
", + "image_path": "8c63fd1c29b95f4d7a08831c7c6f8ff2acdd1bc3844130aa9a1e4b84d0587edf.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 283, + 546, + 319 + ], + "lines": [ + { + "bbox": [ + 46, + 283, + 546, + 319 + ], + "spans": [ + { + "bbox": [ + 46, + 283, + 546, + 319 + ], + "type": "text", + "content": "Table 4: Comparison with other state-of-the-art methods on zero-shot Covid-19 opacity region grounding task. \"Direct COVID-19\" refers to directly use \"Covid-19\" to construct the prompt sentence for entity encoding while \"Covid-19 Description\" refers to replace the name \"Covid-19\" with its description. Our method can achieve better performance on different metrics." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 340, + 287, + 422 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 340, + 287, + 422 + ], + "spans": [ + { + "bbox": [ + 46, + 340, + 287, + 422 + ], + "type": "text", + "content": "RSNA pneumonia dataset and from 0.71 to 0.89 on SIIM-ACR pneumothorax dataset, as shown in Tab. 1. This shows that our method can better deal with the multi-center and multi-disease data distribution in medical. While on ChestX-ray14 dataset, we improve the average AUC scores from 0.69 to 0.77, we refer the reader to supplementary material (Sec. D) for detailed comparison of 14 diseases." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 427, + 288, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 427, + 288, + 594 + ], + "spans": [ + { + "bbox": [ + 46, + 427, + 288, + 594 + ], + "type": "text", + "content": "Unseen Diseases. Here, we are considering a strict setting for openset classification, in particular, we use covid-19 to evaluate the systems. Covid-19 is a new disease that only appeared in 2019, MIMIC-CXR reports collected in the year 2015 do not include any entity of covid-19, thus it requires the system to have the ability to diagnose truly unseen diseases. As shown in Tab. 2, existing approaches that only rely on disease name struggles to make the correct diagnosis. While, our proposed approach, after introducing medical knowledge, i.e., using entity descriptions, can understand the complex medical entity descriptions unseen in the training set, and significantly boost the performance from 0.66 to 0.74 on AUC and from 0.59 to 0.70 on ACC, demonstrating entity translation is vital for unseen diseases." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 610, + 128, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 610, + 128, + 623 + ], + "spans": [ + { + "bbox": [ + 47, + 610, + 128, + 623 + ], + "type": "text", + "content": "5.1.2 Grounding" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 629, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 287, + 715 + ], + "type": "text", + "content": "In addition to the plain diagnosis, explainability can be equally critical in healthcare, improving the reliability and trustiness of the machine learning systems. Here, we consider providing explainability by grounding the abnormality in the prediction and compare against the existing approaches. Similarly, we split the diseases into seen and unseen ones, depending on whether their names have ap" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 340, + 546, + 389 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 340, + 546, + 389 + ], + "spans": [ + { + "bbox": [ + 304, + 340, + 546, + 389 + ], + "type": "text", + "content": "peared in the medical reports. Specifically, \"Pneumonia\" and \"Pneumothorax\" are treated as seen, and \"Covid-19\" is treated as unseen. Due to the space limitation, we include visualization results in supplementary material (Sec. E)." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 407, + 546, + 563 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 407, + 546, + 563 + ], + "spans": [ + { + "bbox": [ + 304, + 407, + 546, + 563 + ], + "type": "text", + "content": "Seen Diseases. We show the results for grounding on RSNA Pneumonia opacity and SIIM-ACR Pneumothorax collapse in Tab. 3. As shown in Tab. 3a, our proposed model surpasses existing approaches on all metrics, for example, we improve the pointing game score from 0.83 to 0.87, the detection Recall from 0.85 to 0.87, the detection precision from 0.50 to 0.64, the IOU from 0.30 to 0.32 and the Dice from 0.44 to 0.46. While on SIIM-ACR dataset (Tab. 3b), the pneumothorax region tends to be thin and narrow, localizing it can often be more challenging than that of opacity grounding [6], we thus only consider pointing game, recall, and precision. Similarly, our method can achieve significantly better performance than prior approaches." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "type": "text", + "content": "Unseen Diseases. We also conduct the zero-shot grounding experiment on the unseen disease, namely, Covid-19, as shown in Tab. 4. Our model has shown consistent improvements in all metrics, e.g., boosting the pointing game score from 0.40 to 0.58. One observation to be noticed is that, results in Tab. 4 are mostly consistent with those in Tab. 2, i.e., better classification results tend to lead to better grounding. Overall, our model with knowledge-enhanced language encoding has facilitated the visual encoder to learn underlying evidence relating to the diseases, therefore, leading to more interpretable representations than prior approaches." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "21378" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 62, + 71, + 530, + 152 + ], + "blocks": [ + { + "bbox": [ + 62, + 71, + 530, + 152 + ], + "lines": [ + { + "bbox": [ + 62, + 71, + 530, + 152 + ], + "spans": [ + { + "bbox": [ + 62, + 71, + 530, + 152 + ], + "type": "table", + "html": "
Dataset Data PortionPneumoniaPneumothoraxCovid-19ChestX-ray14
1%10%100%1%10%100%1%10%100%1%10%100%
Scratch0.71070.81500.86260.43470.61200.65710.78610.91620.95540.60050.73650.7924
ConVIRT [68]0.83980.85620.87610.71340.78260.90040.86750.95410.97260.66150.76580.8128
GLoRIA [25]0.85990.86660.88460.74390.85380.90140.90650.93810.97280.67100.76420.8184
BioViL [6]0.82330.85380.88360.69480.77750.86890.89890.95290.97290.69520.75270.8245
Ours0.87310.87990.89310.85270.90710.91880.92240.96570.97290.77210.78940.8323
", + "image_path": "b158c5d30a1bc042dd8c12c147a9cdde0a3069b441872af7c125740b3c474185.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 73, + 188, + 519, + 271 + ], + "blocks": [ + { + "bbox": [ + 46, + 156, + 547, + 180 + ], + "lines": [ + { + "bbox": [ + 46, + 156, + 547, + 180 + ], + "spans": [ + { + "bbox": [ + 46, + 156, + 547, + 180 + ], + "type": "text", + "content": "Table 5: Comparison of AUC scores with other state-of-the-art methods on fine-tuning classification task. The macro average of AUC scores on 14 diseases are reported for ChestX-ray14 dataset." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 73, + 188, + 519, + 271 + ], + "lines": [ + { + "bbox": [ + 73, + 188, + 519, + 271 + ], + "spans": [ + { + "bbox": [ + 73, + 188, + 519, + 271 + ], + "type": "table", + "html": "
Diseases Data PortionPneumoniaPneumothoraxCovid-19
1%10%100%1%10%100%1%10%100%
Scratch0.43470.60470.70680.21330.33230.74470.14810.23670.3228
ConVIRT [68]0.57060.64910.72010.54060.61210.73520.19950.27240.3737
GLoRIA [25]0.65550.69070.73280.56730.57780.76940.18890.28090.3869
BioViL [6]0.68240.70380.72490.62670.69980.78490.21130.32390.4162
Ours0.70640.71620.75790.66590.72100.79370.24450.35390.4399
", + "image_path": "f83ccbcef85eb6ab8a72b7bd346defb132755ee0c3fd6e650eec13b45dace0f2.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 50, + 319, + 541, + 403 + ], + "blocks": [ + { + "bbox": [ + 46, + 274, + 547, + 310 + ], + "lines": [ + { + "bbox": [ + 46, + 274, + 547, + 310 + ], + "spans": [ + { + "bbox": [ + 46, + 274, + 547, + 310 + ], + "type": "text", + "content": "Table 6: Comparison of Dice scores with other state-of-the-art methods on fine-tuning segmentation tasks. Three diseases are reported, and for each disease, three data portions, " + }, + { + "bbox": [ + 46, + 274, + 547, + 310 + ], + "type": "inline_equation", + "content": "1\\%" + }, + { + "bbox": [ + 46, + 274, + 547, + 310 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 274, + 547, + 310 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 46, + 274, + 547, + 310 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 274, + 547, + 310 + ], + "type": "inline_equation", + "content": "100\\%" + }, + { + "bbox": [ + 46, + 274, + 547, + 310 + ], + "type": "text", + "content": " are adopted to show the performance change under different data amounts." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 319, + 541, + 403 + ], + "lines": [ + { + "bbox": [ + 50, + 319, + 541, + 403 + ], + "spans": [ + { + "bbox": [ + 50, + 319, + 541, + 403 + ], + "type": "table", + "html": "
Methods0123AVG
AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑AUC↑F1↑ACC↑
Scratch0.76310.70360.67380.53830.35930.32230.66920.43280.70120.84200.56940.87700.70310.51630.6436
ConVIRT [68]0.84530.77690.77930.60990.39380.46290.72020.48430.64450.90470.61540.88090.77000.56760.6919
GLoRIA [25]0.83040.75770.75200.62080.39910.49220.73390.49580.70370.92460.66670.91020.77740.57980.7145
BioViL [6]0.80340.73780.71480.60350.39120.45700.68600.44970.67770.92290.65000.91600.75400.55720.6914
Ours0.85020.76460.75390.66410.41400.53920.76050.52660.70310.88450.62500.91600.78980.58260.7280
", + "image_path": "39e9d20d07831c4ca7986eed2711dfe436a7c0fd5203d9aeb9083dc92a7c3e43.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 406, + 545, + 431 + ], + "lines": [ + { + "bbox": [ + 46, + 406, + 545, + 431 + ], + "spans": [ + { + "bbox": [ + 46, + 406, + 545, + 431 + ], + "type": "text", + "content": "Table 7: Comparison with other state-of-the-art methods on fine-tuning edema severity grading multi-class classification task. AUC score is reported in the Table. \"0,1,2,3\" in the table represents the severity level and final average scores are reported." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 47, + 448, + 178, + 460 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 448, + 178, + 460 + ], + "spans": [ + { + "bbox": [ + 47, + 448, + 178, + 460 + ], + "type": "text", + "content": "5.2. Fine-tuning Evaluation" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 470, + 288, + 565 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 470, + 288, + 565 + ], + "spans": [ + { + "bbox": [ + 46, + 470, + 288, + 565 + ], + "type": "text", + "content": "In this section, we consider the fine-tuning scenario, with the pre-trained model as initialization, and trained end-to-end on the downstream tasks. We test on three different tasks, namely, classification, segmentation, and grading. In classification and segmentation, the test splits and metrics are the same as in the \"zero-shot\" section. Grading is a new task we introduce in fine-tuning setting, which can be seen as a fine-grained classification task." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 592, + 137, + 604 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 592, + 137, + 604 + ], + "spans": [ + { + "bbox": [ + 47, + 592, + 137, + 604 + ], + "type": "text", + "content": "5.2.1 Classification" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 617, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 287, + 713 + ], + "type": "text", + "content": "We experiment on four different datasets, using " + }, + { + "bbox": [ + 46, + 617, + 287, + 713 + ], + "type": "inline_equation", + "content": "1\\%" + }, + { + "bbox": [ + 46, + 617, + 287, + 713 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 617, + 287, + 713 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 46, + 617, + 287, + 713 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 617, + 287, + 713 + ], + "type": "inline_equation", + "content": "100\\%" + }, + { + "bbox": [ + 46, + 617, + 287, + 713 + ], + "type": "text", + "content": " of the data for fine-tuning, that is consistent with the existing work [68, 25, 6]. As shown in Tab. 5, our model has demonstrated substantial improvements in the AUC scores over the existing approaches across all datasets, reflecting that our pre-trained representation is of higher quality than existing models. We refer the readers to the supplementary material (Sec. D) for more detailed comparison results." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 448, + 398, + 460 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 448, + 398, + 460 + ], + "spans": [ + { + "bbox": [ + 306, + 448, + 398, + 460 + ], + "type": "text", + "content": "5.2.2 Segmentation" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 475, + 545, + 548 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 475, + 545, + 548 + ], + "spans": [ + { + "bbox": [ + 304, + 475, + 545, + 548 + ], + "type": "text", + "content": "In Tab. 6, we conduct fine-tuning experiments on three different diseases for segmentation. We pick " + }, + { + "bbox": [ + 304, + 475, + 545, + 548 + ], + "type": "inline_equation", + "content": "1\\%" + }, + { + "bbox": [ + 304, + 475, + 545, + 548 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 475, + 545, + 548 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 304, + 475, + 545, + 548 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 475, + 545, + 548 + ], + "type": "inline_equation", + "content": "100\\%" + }, + { + "bbox": [ + 304, + 475, + 545, + 548 + ], + "type": "text", + "content": " of the data for fine-tuning. For all three different diseases with different image distributions, our methods surpass the existing state-of-the-art methods by a large margin, especially under the low-data regime." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 578, + 376, + 591 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 578, + 376, + 591 + ], + "spans": [ + { + "bbox": [ + 306, + 578, + 376, + 591 + ], + "type": "text", + "content": "5.2.3 Grading" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "text", + "content": "Besides diagnosis, grading the disease severity level also plays an important role. Here, we adopt our pre-trained features and train them for the multi-class classification task, with 0 to 3 representing different severity levels. As shown in Tab. 7, for each level, the AUC, F1, and ACC scores are calculated as one class against all other ones, for example, 0 vs " + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\{1,2,3\\}" + }, + { + "bbox": [ + 304, + 605, + 545, + 713 + ], + "type": "text", + "content": ". Final macro average scores of four levels are computed. On the majority of severity levels, our method can achieve the best results." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "21379" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 119, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 119, + 83 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 119, + 83 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 91, + 289, + 273 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 91, + 289, + 273 + ], + "spans": [ + { + "bbox": [ + 46, + 91, + 289, + 273 + ], + "type": "text", + "content": "In this paper, we introduce a novel medical knowledge enhanced VLP model. First, we propose a triplet extraction module to extract useful medical-related triplets as more useful supervision signals, simplifying complex raw reports with minimal information loss. Second, we translate the entities in extracted triplets into detailed medical descriptions and embed them with a text encoder enabling the network to understand complex medical expert-level knowledge. Finally, a transformer-based structure is proposed to do local region alignment. In experiments, We evaluate our method on different datasets under various settings. Our method shows strong zero-shot classification and grounding abilities, even facing unseen diseases. Additionally, with finetuning, our method still outperforms state-of-the-art methods significantly, showing the superiority of our method." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 284, + 145, + 298 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 284, + 145, + 298 + ], + "spans": [ + { + "bbox": [ + 47, + 284, + 145, + 298 + ], + "type": "text", + "content": "Acknowledgement" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 304, + 288, + 365 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 304, + 288, + 365 + ], + "spans": [ + { + "bbox": [ + 47, + 304, + 288, + 365 + ], + "type": "text", + "content": "This work is supported by the National Key R&D Program of China (No. 2022ZD0160702), STCSM (No. 22511106101, No. 18DZ2270700, No. 21DZ1100100), 111 plan (No. BP0719010), and State Key Laboratory of UHD Video and Audio Production and Presentation." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 377, + 107, + 390 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 377, + 107, + 390 + ], + "spans": [ + { + "bbox": [ + 47, + 377, + 107, + 390 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 398, + 288, + 714 + ], + "type": "list", + "angle": 0, + "index": 11, + "blocks": [ + { + "bbox": [ + 53, + 398, + 287, + 441 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 398, + 287, + 441 + ], + "spans": [ + { + "bbox": [ + 53, + 398, + 287, + 441 + ], + "type": "text", + "content": "[1] Society for imaging informatics in medicine: Siim-acr pneumothorax segmentation. https://www.kaggle.com/c/siim-acr-pneumothorax-segmentation.2019." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 443, + 287, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 443, + 287, + 510 + ], + "spans": [ + { + "bbox": [ + 53, + 443, + 287, + 510 + ], + "type": "text", + "content": "[2] Emily Alsentzer, John Murphy, William Boag, Wei-Hung Weng, Di Jin, Tristan Naumann, and Matthew McDermott. Publicly available clinical BERT embeddings. In Proceedings of the 2nd Clinical Natural Language Processing Workshop, pages 72-78, Minneapolis, Minnesota, USA, June 2019. Association for Computational Linguistics." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 510, + 287, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 510, + 287, + 555 + ], + "spans": [ + { + "bbox": [ + 53, + 510, + 287, + 555 + ], + "type": "text", + "content": "[3] Emily Alsentzer, John R Murphy, Willie Boag, WeiHung Weng, Di Jin, Tristan Naumann, WA Redmond, and Matthew BA McDermott. Publicly available clinical bert embeddings. *NAACL HLT* 2019, page 72, 2019." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 556, + 287, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 556, + 287, + 600 + ], + "spans": [ + { + "bbox": [ + 53, + 556, + 287, + 600 + ], + "type": "text", + "content": "[4] Federico Bianchi, Giuseppe Attanasio, Raphael Pisoni, Silvia Terragni, Gabriele Sarti, and Sri Lakshmi. Contrastive language-image pre-training for the italian language. arXiv preprint arXiv:2108.08688, 2021." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 601, + 287, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 601, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 53, + 601, + 287, + 635 + ], + "type": "text", + "content": "[5] Olivier Bodenreider. The unified medical language system (umlts): integrating biomedical terminology. *Nucleic acids research*, 32(suppl_1):D267–D270, 2004." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 636, + 288, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 636, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 53, + 636, + 288, + 714 + ], + "type": "text", + "content": "[6] Benedikt Boecking, Naoto Usuyama, Shruthi Bannur, Daniel C Castro, Anton Schwaighofer, Stephanie Hyland, Maria Wetscherek, Tristan Naumann, Aditya Nori, Javier Alvarez-Valle, et al. Making the most of text semantics to improve biomedical vision-language processing. In European conference on computer vision, pages 1-21, 2022. Official Implementa" + } + ] + } + ], + "index": 10 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 24, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "text", + "content": "tion: https://github.com/microsoft/hi-ml/tree/main/hi-ml-multimodal." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 312, + 96, + 547, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 96, + 547, + 173 + ], + "spans": [ + { + "bbox": [ + 312, + 96, + 547, + 173 + ], + "type": "text", + "content": "[7] Geeticka Chauhan, Ruizhi Liao, William Wells, Jacob Andreas, Xin Wang, Seth Berkowitz, Steven Horng, Peter Szolovits, and Polina Golland. Joint modeling of chest radiographs and radiology reports for pulmonary edema assessment. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 529-539. Springer, 2020." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 312, + 175, + 545, + 229 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 175, + 545, + 229 + ], + "spans": [ + { + "bbox": [ + 312, + 175, + 545, + 229 + ], + "type": "text", + "content": "[8] Sihong Chen, Jing Qin, Xing Ji, Baiying Lei, Tianfu Wang, Dong Ni, and Jie-Zhi Cheng. Automatic scoring of multiple semantic attributes with multi-task feature leverage: a study on pulmonary nodules in ct images. IEEE transactions on medical imaging, 36(3):802-814, 2016." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 312, + 230, + 545, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 230, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 312, + 230, + 545, + 285 + ], + "type": "text", + "content": "[9] Yen-Chun Chen, Linjie Li, Licheng Yu, Ahmed El Kholy, Faisal Ahmed, Zhe Gan, Yu Cheng, and Jingjing Liu. Uniter: Universal image-text representation learning. In European conference on computer vision, pages 104-120. Springer, 2020." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 286, + 545, + 341 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 286, + 545, + 341 + ], + "spans": [ + { + "bbox": [ + 307, + 286, + 545, + 341 + ], + "type": "text", + "content": "[10] Zhihong Chen, Guanbin Li, and Xiang Wan. Align, reason and learn: Enhancing medical vision-and-language pretraining with knowledge. In Proceedings of the 30th ACM International Conference on Multimedia, pages 5152-5161, 2022." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 342, + 545, + 397 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 342, + 545, + 397 + ], + "spans": [ + { + "bbox": [ + 307, + 342, + 545, + 397 + ], + "type": "text", + "content": "[11] Zhihong Chen, Yan Song, Tsung-Hui Chang, and Xiang Wan. Generating radiology reports via memory-driven transformer. In Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP), pages 1439-1449, 2020." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 399, + 545, + 465 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 399, + 545, + 465 + ], + "spans": [ + { + "bbox": [ + 307, + 399, + 545, + 465 + ], + "type": "text", + "content": "[12] Hui Cui, Yiyue Xu, Wanlong Li, Linlin Wang, and Henry Duh. Collaborative learning of cross-channel clinical attention for radiotherapy-related esophageal fistula prediction from ct. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 212-220. Springer, 2020." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 466, + 545, + 531 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 466, + 545, + 531 + ], + "spans": [ + { + "bbox": [ + 307, + 466, + 545, + 531 + ], + "type": "text", + "content": "[13] Yuhao Cui, Zhou Yu, Chunqi Wang, Zhongzhou Zhao, Ji Zhang, Meng Wang, and Jun Yu. Rosita: Enhancing vision-and-language semantic alignments via cross-and intra-modal knowledge integration. In Proceedings of the 29th ACM International Conference on Multimedia, pages 797-806, 2021." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 533, + 545, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 533, + 545, + 588 + ], + "spans": [ + { + "bbox": [ + 307, + 533, + 545, + 588 + ], + "type": "text", + "content": "[14] Jean-Benoit Delbrouck, Pierre Chambon, Christian Bluethgen, Emily Tsai, Omar Almusa, and Curtis P Langlotz. Improving the factual correctness of radiology report generation with semantic rewards. arXiv preprint arXiv:2210.12186, 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 590, + 545, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 590, + 545, + 644 + ], + "spans": [ + { + "bbox": [ + 307, + 590, + 545, + 644 + ], + "type": "text", + "content": "[15] Shivang Desai, Ahmad Baghal, Thidathip Wongsurawat, Piroon Jenjaroenpun, Thomas Powell, Shaymaa Al-Shukri, Kim Gates, Phillip Farmer, Michael Rutherford, Geri Blake, et al. Chest imaging representing a Covid-19 positive rural us population. Scientific data, 7(1):1-6, 2020." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 646, + 545, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 646, + 545, + 690 + ], + "spans": [ + { + "bbox": [ + 307, + 646, + 545, + 690 + ], + "type": "text", + "content": "[16] Foivos I Diakogiannis, François Waldner, Peter Caccetta, and Chen Wu. Resunet-a: A deep learning framework for semantic segmentation of remotely sensed data. ISPRS Journal of Photogrammetry and Remote Sensing, 162:94-114, 2020." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 691, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 691, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 691, + 545, + 713 + ], + "type": "text", + "content": "[17] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner," + } + ] + } + ], + "index": 23 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "21380" + } + ] + } + ], + "index": 25 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 116 + ], + "type": "text", + "content": "Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In International Conference on Learning Representations, 2020." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 118, + 287, + 171 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 118, + 287, + 171 + ], + "spans": [ + { + "bbox": [ + 48, + 118, + 287, + 171 + ], + "type": "text", + "content": "[18] Jared A Dunnmon, Alexander J Ratner, Khaled Saab, Nishith Khandwala, Matthew Markert, Hersh Sagreiya, Roger Goldman, Christopher Lee-Messer, Matthew P Lungren, Daniel L Rubin, et al. Cross-modal data programming enables rapid medical machine learning. *Patterns*, 1(2):100019, 2020." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 173, + 286, + 205 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 173, + 286, + 205 + ], + "spans": [ + { + "bbox": [ + 48, + 173, + 286, + 205 + ], + "type": "text", + "content": "[19] Bradley J Erickson, Panagiotis Korfiatis, Zeynettin Akkus, and Timothy L Kline. Machine learning for medical imaging. Radiographics, 37(2):505, 2017." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 206, + 286, + 249 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 206, + 286, + 249 + ], + "spans": [ + { + "bbox": [ + 48, + 206, + 286, + 249 + ], + "type": "text", + "content": "[20] Andre Esteva, Brett Kuprel, Roberto A Novoa, Justin Ko, Susan M Swetter, Helen M Blau, and Sebastian Thrun. Dermatologist-level classification of skin cancer with deep neural networks. nature, 542(7639):115-118, 2017." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 251, + 286, + 304 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 251, + 286, + 304 + ], + "spans": [ + { + "bbox": [ + 48, + 251, + 286, + 304 + ], + "type": "text", + "content": "[21] Leyuan Fang, Chong Wang, Shutao Li, Hossein Rabbani, Xiangdong Chen, and Zhimin Liu. Attention to lesion: Lesion-aware convolutional neural network for retinal optical coherence tomography image classification. IEEE transactions on medical imaging, 38(8):1959-1970, 2019." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 305, + 286, + 370 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 305, + 286, + 370 + ], + "spans": [ + { + "bbox": [ + 48, + 305, + 286, + 370 + ], + "type": "text", + "content": "[22] Ary L Goldberger, Luis AN Amaral, Leon Glass, Jeffrey M Hausdorff, Plamen Ch Ivanov, Roger G Mark, Joseph E Mietus, George B Moody, Chung-Kang Peng, and H Eugene Stanley. Physiobank, physiotoolkit, and physionet: components of a new research resource for complex physiologic signals. circulation, 101(23):e215-e220, 2000." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 372, + 286, + 415 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 372, + 286, + 415 + ], + "spans": [ + { + "bbox": [ + 48, + 372, + 286, + 415 + ], + "type": "text", + "content": "[23] Ivan Gonzalez-Diaz. Dermaknet: Incorporating the knowledge of dermatologists to convolutional neural networks for skin lesion diagnosis. IEEE journal of biomedical and health informatics, 23(2):547-559, 2018." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 416, + 286, + 458 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 416, + 286, + 458 + ], + "spans": [ + { + "bbox": [ + 48, + 416, + 286, + 458 + ], + "type": "text", + "content": "[24] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 460, + 286, + 536 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 460, + 286, + 536 + ], + "spans": [ + { + "bbox": [ + 48, + 460, + 286, + 536 + ], + "type": "text", + "content": "[25] Shih-Cheng Huang, Liyue Shen, Matthew P Lungren, and Serena Yeung. Gloria: A multimodal global-local representation learning framework for label-efficient medical image recognition. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 3942-3951, 2021. Official Implementation: https://github.com/ marshuang80/gloria." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 537, + 286, + 590 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 537, + 286, + 590 + ], + "spans": [ + { + "bbox": [ + 48, + 537, + 286, + 590 + ], + "type": "text", + "content": "[26] Xin Huang, Yu Fang, Mingming Lu, Fengqi Yan, Jun Yang, and Yilu Xu. Dual-ray net: automatic diagnosis of thoracic diseases using frontal and lateral chest x-rays. Journal of Medical Imaging and Health Informatics, 10(2):348-355, 2020." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 592, + 286, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 592, + 286, + 645 + ], + "spans": [ + { + "bbox": [ + 48, + 592, + 286, + 645 + ], + "type": "text", + "content": "[27] Sarfaraz Hussein, Kunlin Cao, Qi Song, and Ulas Bagci. Risk stratification of lung nodules using 3d cnn-based multitask learning. In International conference on information processing in medical imaging, pages 249-260. Springer, 2017." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 647, + 286, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 286, + 712 + ], + "type": "text", + "content": "[28] Jeremy Irvin, Pranav Rajpurkar, Michael Ko, Yifan Yu, Silviana Ciurea-Ilicus, Chris Chute, Henrik Marklund, Behzad Haghgoo, Robyn Ball, Katie Shpanskaya, et al. Chexpert: A large chest radiograph dataset with uncertainty labels and expert comparison. In Proceedings of the AAAI conference on artificial intelligence, volume 33, pages 590-597, 2019." + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 25, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 148 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 148 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 148 + ], + "type": "text", + "content": "[29] Saahil Jain, Ashwin Agrawal, Adriel Saporta, Steven Truong, Tan Bui, Pierre Chambon, Yuhao Zhang, Matthew P Lungren, Andrew Y Ng, Curtis Langlotz, et al. Radgraph: Extracting clinical entities and relations from radiology reports. In Thirty-fifth Conference on Neural Information Processing Systems Datasets and Benchmarks Track (Round 1), 2021." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 307, + 150, + 545, + 214 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 150, + 545, + 214 + ], + "spans": [ + { + "bbox": [ + 307, + 150, + 545, + 214 + ], + "type": "text", + "content": "[30] Chao Jia, Yinfei Yang, Ye Xia, Yi-Ting Chen, Zarana Parekh, Hieu Pham, Quoc Le, Yun-Hsuan Sung, Zhen Li, and Tom Duerig. Scaling up visual and vision-language representation learning with noisy text supervision. In International Conference on Machine Learning, pages 4904-4916. PMLR, 2021." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 217, + 545, + 248 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 217, + 545, + 248 + ], + "spans": [ + { + "bbox": [ + 307, + 217, + 545, + 248 + ], + "type": "text", + "content": "[31] AEWP Johnson, Tom Pollard, Roger Mark, Seth Berkowitz, and Steven Horng. Mimic-cxr database. PhysioNet10, 13026:C2JT1Q, 2019." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 250, + 545, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 250, + 545, + 293 + ], + "spans": [ + { + "bbox": [ + 307, + 250, + 545, + 293 + ], + "type": "text", + "content": "[32] Junnan Li, Dongxu Li, Caiming Xiong, and Steven Hoi. Blip: Bootstrapping language-image pre-training for unified vision-language understanding and generation. arXiv preprint arXiv:2201.12086, 2022." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 294, + 545, + 348 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 294, + 545, + 348 + ], + "spans": [ + { + "bbox": [ + 307, + 294, + 545, + 348 + ], + "type": "text", + "content": "[33] Junnan Li, Ramprasaath Selvaraju, Akhilesh Gotmare, Shafiq Joty, Caiming Xiong, and Steven Chu Hong Hoi. Align before fuse: Vision and language representation learning with momentum distillation. Advances in neural information processing systems, 34:9694-9705, 2021." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 350, + 545, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 350, + 545, + 403 + ], + "spans": [ + { + "bbox": [ + 307, + 350, + 545, + 403 + ], + "type": "text", + "content": "[34] Liu Li, Mai Xu, Xiaofei Wang, Lai Jiang, and Hanruo Liu. Attention based glaucoma detection: a large-scale database and cnn model. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 10571-10580, 2019." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 404, + 545, + 446 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 404, + 545, + 446 + ], + "spans": [ + { + "bbox": [ + 307, + 404, + 545, + 446 + ], + "type": "text", + "content": "[35] Liunian Harold Li, Mark Yatskar, Da Yin, Cho-Jui Hsieh, and Kai-Wei Chang. Visualbert: A simple and perform-. mant baseline for vision and language. arXiv preprint arXiv:1908.03557, 2019." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 449, + 545, + 502 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 449, + 545, + 502 + ], + "spans": [ + { + "bbox": [ + 307, + 449, + 545, + 502 + ], + "type": "text", + "content": "[36] Mingjie Li, Wenjia Cai, Karin Verspoor, Shirui Pan, Xiaodan Liang, and Xiaojun Chang. Cross-modal clinical graph transformer for ophthalmic report generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 20656-20665, 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 504, + 545, + 557 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 504, + 545, + 557 + ], + "spans": [ + { + "bbox": [ + 307, + 504, + 545, + 557 + ], + "type": "text", + "content": "[37] Xiaomeng Li, Xiaowei Hu, Lequan Yu, Lei Zhu, Chi-Wing Fu, and Pheng-Ann Heng. Canet: cross-disease attention network for joint diabetic retinopathy and diabetic macular edema grading. IEEE transactions on medical imaging, 39(5):1483-1493, 2019." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 559, + 545, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 559, + 545, + 634 + ], + "spans": [ + { + "bbox": [ + 307, + 559, + 545, + 634 + ], + "type": "text", + "content": "[38] Xiujun Li, Xi Yin, Chunyuan Li, Pengchuan Zhang, Xiaowei Hu, Lei Zhang, Lijuan Wang, Houdong Hu, Li Dong, Furu Wei, et al. Oscar: Object-semantics aligned pre-training for vision-language tasks. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XXX 16, pages 121-137. Springer, 2020." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 636, + 545, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 636, + 545, + 678 + ], + "spans": [ + { + "bbox": [ + 307, + 636, + 545, + 678 + ], + "type": "text", + "content": "[39] Qing Liao, Ye Ding, Zoe L Jiang, Xuan Wang, Chunkai Zhang, and Qian Zhang. Multi-task deep convolutional neural network for cancer diagnosis. Neurocomputing, 348:66-73, 2019." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 681, + 545, + 713 + ], + "type": "text", + "content": "[40] Fenglin Liu, Xian Wu, Shen Ge, Wei Fan, and Yuexian Zou. Exploring and distilling posterior and prior knowledge for radiology report generation. In Proceedings of" + } + ] + } + ], + "index": 24 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "21381" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 73, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 67, + 73, + 286, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 73, + 286, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 73, + 286, + 95 + ], + "type": "text", + "content": "the IEEE/CVF conference on computer vision and pattern recognition, pages 13753-13762, 2021." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 148 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 148 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 148 + ], + "type": "text", + "content": "[41] Weijie Liu, Peng Zhou, Zhe Zhao, Zhiruo Wang, Qi Ju, Haotang Deng, and Ping Wang. K-bert: Enabling language representation with knowledge graph. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 2901-2908, 2020." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 150, + 287, + 183 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 150, + 287, + 183 + ], + "spans": [ + { + "bbox": [ + 48, + 150, + 287, + 183 + ], + "type": "text", + "content": "[42] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. In International Conference on Learning Representations, 2018." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 184, + 287, + 238 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 184, + 287, + 238 + ], + "spans": [ + { + "bbox": [ + 48, + 184, + 287, + 238 + ], + "type": "text", + "content": "[43] Gabriel Maicas, Andrew P Bradley, Jacinto C Nascimento, Ian Reid, and Gustavo Carneiro. Training medical image analysis systems like radiologists. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 546-554. Springer, 2018." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 239, + 287, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 239, + 287, + 293 + ], + "spans": [ + { + "bbox": [ + 48, + 239, + 287, + 293 + ], + "type": "text", + "content": "[44] Matthew BA McDermott, Tzu Ming Harry Hsu, Wei-Hung Weng, Marzyeh Ghassemi, and Peter Szolovits. Chexpert++: Approximating the chexpert labeler for speed, differentiability, and probabilistic output. In Machine Learning for Healthcare Conference, pages 913-927. PMLR, 2020." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 294, + 287, + 348 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 294, + 287, + 348 + ], + "spans": [ + { + "bbox": [ + 48, + 294, + 287, + 348 + ], + "type": "text", + "content": "[45] Masahiro Mitsuhara, Hiroshi Fukui, Yusuke Sakashita, Takanori Ogata, Tsubasa Hirakawa, Takayoshi Yamashita, and Hironobu Fujiyoshi. Embedding human knowledge into deep neural network via attention map. arXiv preprint arXiv:1905.03540, 2019." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 350, + 287, + 415 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 350, + 287, + 415 + ], + "spans": [ + { + "bbox": [ + 48, + 350, + 287, + 415 + ], + "type": "text", + "content": "[46] Yasuhide Miura, Yuhao Zhang, Emily Tsai, Curtis Langlotz, and Dan Jurafsky. Improving factual completeness and consistency of image-to-text radiology report generation. In Proceedings of the 2021 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pages 5288-5304, 2021." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 416, + 287, + 458 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 416, + 287, + 458 + ], + "spans": [ + { + "bbox": [ + 48, + 416, + 287, + 458 + ], + "type": "text", + "content": "[47] Philip Müller, Georgios Kaissis, Congyu Zou, and Daniel Rückert. Joint learning of localized representations from medical images and reports. arXiv preprint arXiv:2112.02889, 2021." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 460, + 287, + 525 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 460, + 287, + 525 + ], + "spans": [ + { + "bbox": [ + 48, + 460, + 287, + 525 + ], + "type": "text", + "content": "[48] Maya Pavlova, Naomi Terhljan, Audrey G Chung, Andy Zhao, Siddharth Surana, Hossein Aboutalebi, Hayden Gunraj, Ali Sabri, Amer Alaref, and Alexander Wong. Covid-net cxr-2: An enhanced deep convolutional neural network design for detection of COVID-19 cases from chest x-ray images. Frontiers in Medicine, 9, 2022." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 526, + 287, + 580 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 526, + 287, + 580 + ], + "spans": [ + { + "bbox": [ + 48, + 526, + 287, + 580 + ], + "type": "text", + "content": "[49] Yifan Peng, Xiaosong Wang, Le Lu, Mohammadhadi Bagheri, Ronald Summers, and Zhiyong Lu. Negbio: a high-performance tool for negation and uncertainty detection in radiology reports. AMIA Summits on Translational Science Proceedings, 2018:188, 2018." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 582, + 287, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 582, + 287, + 646 + ], + "spans": [ + { + "bbox": [ + 48, + 582, + 287, + 646 + ], + "type": "text", + "content": "[50] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International Conference on Machine Learning, pages 8748-8763. PMLR, 2021." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 647, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 287, + 712 + ], + "type": "text", + "content": "[51] George Shih, Carol C Wu, Safwan S Halabi, Marc D Kohli, Luciano M Prevedello, Tessa S Cook, Arjun Sharma, Judith K Amorosa, Veronica Arteaga, Maya Galperin-Aizenberg, et al. Augmenting the national institutes of health chest radiograph dataset with expert annotations of possible pneumonia. Radiology. Artificial intelligence, 1(1), 2019." + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 25, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 139 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 139 + ], + "type": "text", + "content": "[52] Akshay Smit, Saahil Jain, Pranav Rajpurkar, Anuj Pareek, Andrew Y Ng, and Matthew Lungren. Combining automatic labelers and expert annotations for accurate radiology report labeling using bert. In Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP), pages 1500-1519, 2020." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 307, + 140, + 545, + 182 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 140, + 545, + 182 + ], + "spans": [ + { + "bbox": [ + 307, + 140, + 545, + 182 + ], + "type": "text", + "content": "[53] Jiaxing Tan, Yumei Huo, Zhengrong Liang, and Lihong Li. Expert knowledge-infused deep learning for automatic lung nodule detection. Journal of X-ray Science and Technology, 27(1):17-35, 2019." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 308, + 183, + 545, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 183, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 308, + 183, + 545, + 228 + ], + "type": "text", + "content": "[54] Haiming Tang, Nanfei Sun, and Yi Li. Deep learning segmentation model for automated detection of the opacity regions in the chest x-rays of the COVID-19 positive patients and the application for disease severity. medRxiv preprint, 2020." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 228, + 545, + 282 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 228, + 545, + 282 + ], + "spans": [ + { + "bbox": [ + 308, + 228, + 545, + 282 + ], + "type": "text", + "content": "[55] Joseph J Titano, Marcus Badgeley, Javin Schefflein, Margaret Pain, Andres Su, Michael Cai, Nathaniel Swinburne, John Zech, Jun Kim, Joshua Bederson, et al. Automated deep-neural-network surveillance of cranial images for acute neurologic events. Nature medicine, 24(9):1337-1341, 2018." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 283, + 545, + 336 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 283, + 545, + 336 + ], + "spans": [ + { + "bbox": [ + 308, + 283, + 545, + 336 + ], + "type": "text", + "content": "[56] Ekin Tiu, Ellie Talius, Pujan Patel, Curtis P Langlotz, Andrew Y Ng, and Pranav Rajpurkar. Expert-level detection of pathologies from unannotated chest x-ray images via self-supervised learning. Nature Biomedical Engineering, pages 1-8, 2022." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 338, + 545, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 338, + 545, + 392 + ], + "spans": [ + { + "bbox": [ + 308, + 338, + 545, + 392 + ], + "type": "text", + "content": "[57] Kun Wang, Xiaohong Zhang, Sheng Huang, Feiyu Chen, Xiangbo Zhang, and Luwen Huangfu. Learning to recognize thoracic disease in chest x-rays with knowledge-guided deep zoom neural networks. IEEE Access, 8:159790-159805, 2020." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 393, + 545, + 469 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 393, + 545, + 469 + ], + "spans": [ + { + "bbox": [ + 308, + 393, + 545, + 469 + ], + "type": "text", + "content": "[58] Xiaosong Wang, Yifan Peng, Le Lu, Zhiyong Lu, Mohammadhadi Bagheri, and Ronald M Summers. Chestx-ray8: Hospital-scale chest x-ray database and benchmarks on weakly-supervised classification and localization of common thorax diseases. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2097-2106, 2017." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 471, + 545, + 536 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 471, + 545, + 536 + ], + "spans": [ + { + "bbox": [ + 308, + 471, + 545, + 536 + ], + "type": "text", + "content": "[59] Zhanyu Wang, Mingkang Tang, Lei Wang, Xiu Li, and Luping Zhou. A medical semantic-assisted transformer for radiographic report generation. In Medical Image Computing and Computer Assisted Intervention-MICCAI 2022: 25th International Conference, Singapore, September 18-22, 2022, Proceedings, Part III, pages 655-664. Springer, 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 537, + 545, + 569 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 537, + 545, + 569 + ], + "spans": [ + { + "bbox": [ + 308, + 537, + 545, + 569 + ], + "type": "text", + "content": "[60] Zifeng Wang, Zhenbang Wu, Dinesh Agarwal, and Jimeng Sun. Medclip: Contrastive learning from unpaired medical images and text. arXiv preprint arXiv:2210.10163, 2022." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 570, + 545, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 570, + 545, + 646 + ], + "spans": [ + { + "bbox": [ + 308, + 570, + 545, + 646 + ], + "type": "text", + "content": "[61] Joy T Wu, Nkechinyere Nneka Agu, Ismini Lourentzou, Arjun Sharma, Joseph Alexander Paguio, Jasper Seth Yao, Edward Christopher Dee, William G Mitchell, Satyananda Kashyap, Andrea Giovannini, et al. Chest imagenome dataset for clinical reasoning. In Thirty-fifth Conference on Neural Information Processing Systems Datasets and Benchmarks Track (Round 2), 2021." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 647, + 545, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 647, + 545, + 690 + ], + "spans": [ + { + "bbox": [ + 308, + 647, + 545, + 690 + ], + "type": "text", + "content": "[62] Xiaozheng Xie, Jianwei Niu, Xuefeng Liu, Zhengsu Chen, Shaojie Tang, and Shui Yu. A survey on incorporating domain knowledge into deep learning for medical image analysis. Medical Image Analysis, 69:101985, 2021." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 692, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 692, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 692, + 545, + 712 + ], + "type": "text", + "content": "[63] Yutong Xie, Yong Xia, Jianpeng Zhang, Yang Song, Dagan Feng, Michael Fulham, and Weidong Cai. Knowledge-based" + } + ] + } + ], + "index": 24 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 318, + 742 + ], + "type": "text", + "content": "21382" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 429 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "type": "text", + "content": "collaborative deep learning for benign-malignant lung nodule classification on chest ct. IEEE transactions on medical imaging, 38(4):991-1004, 2018." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 287, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 287, + 150 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 287, + 150 + ], + "type": "text", + "content": "[64] Shuxin Yang, Xian Wu, Shen Ge, S Kevin Zhou, and Li Xiao. Knowledge matters: Chest radiology report generation with general and specific knowledge. Medical Image Analysis, 80:102510, 2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 152, + 287, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 152, + 287, + 239 + ], + "spans": [ + { + "bbox": [ + 48, + 152, + 287, + 239 + ], + "type": "text", + "content": "[65] Wenkai Yang, Juanjuan Zhao, Yan Qiang, Xiaotang Yang, Yunyun Dong, Qianqian Du, Guohua Shi, and Muhammad Bilal Zia. Dscgans: Integrate domain knowledge in training dual-path semi-supervised conditional generative adversarial networks and s3vm for ultrasonography thyroid nodules classification. In International conference on medical image computing and computer-assisted intervention, pages 558-566. Springer, 2019." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 240, + 287, + 295 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 240, + 287, + 295 + ], + "spans": [ + { + "bbox": [ + 48, + 240, + 287, + 295 + ], + "type": "text", + "content": "[66] Fei Yu, Jiji Tang, Weichong Yin, Yu Sun, Hao Tian, Hua Wu, and Haifeng Wang. Ernie-vil: Knowledge enhanced vision-language representations through scene graphs. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 3208-3216, 2021." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 297, + 287, + 361 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 297, + 287, + 361 + ], + "spans": [ + { + "bbox": [ + 48, + 297, + 287, + 361 + ], + "type": "text", + "content": "[67] Ke Yu, Shantanu Ghosh, Zhexiong Liu, Christopher Deible, and Kayhan Batmanghelich. Anatomy-guided weakly-supervised abnormality localization in chest x-rays. In International Conference on Medical Image Computing and Computer-Assisted Intervention, pages 658-668. Springer, 2022." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 363, + 287, + 429 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 363, + 287, + 429 + ], + "spans": [ + { + "bbox": [ + 48, + 363, + 287, + 429 + ], + "type": "text", + "content": "[68] Yuhao Zhang, Hang Jiang, Yasuhide Miura, Christopher D Manning, and Curtis P Langlotz. Contrastive learning of medical visual representations from paired images and text. In Machine Learning for Healthcare, 2022. Highest Starred Implementation: https://github.com/edreisMD/ConVIRT-pytorch." + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "spans": [ + { + "bbox": [ + 293, + 732, + 317, + 742 + ], + "type": "text", + "content": "21383" + } + ] + } + ], + "index": 7 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 11 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/cc22facf-9790-4a7c-8861-ea4adecda7ac_content_list.json b/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/cc22facf-9790-4a7c-8861-ea4adecda7ac_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..879f164fa96d857085eca059637df917151c8663 --- /dev/null +++ b/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/cc22facf-9790-4a7c-8861-ea4adecda7ac_content_list.json @@ -0,0 +1,1646 @@ +[ + { + "type": "text", + "text": "Membrane Potential Batch Normalization for Spiking Neural Networks", + "text_level": 1, + "bbox": [ + 124, + 130, + 846, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Yufei Guo,\\* Yuhan Zhang,\\* Yuanpei Chen, Weihang Peng, Xiaode Liu, Liwen Zhang, Xuhui Huang, Zhe Ma\\* Intelligent Science & Technology Academy of CASIC, China Scientific Research Laboratory of Aerospace Intelligent Systems and Technology, China", + "bbox": [ + 135, + 180, + 834, + 252 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 286, + 313, + 301 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "As one of the energy-efficient alternatives of conventional neural networks (CNNs), spiking neural networks (SNNs) have gained more and more interest recently. To train the deep models, some effective batch normalization (BN) techniques are proposed in SNNs. All these BNs are suggested to be used after the convolution layer as usually doing in CNNs. However, the spiking neuron is much more complex with the spatio-temporal dynamics. The regulated data flow after the BN layer will be disturbed again by the membrane potential updating operation before the firing function, i.e., the nonlinear activation. Therefore, we advocate adding another BN layer before the firing function to normalize the membrane potential again, called MPBN. To eliminate the induced time cost of MPBN, we also propose a training-inference-decoupled re-parameterization technique to fold the trained MPBN into the firing threshold. With the re-parameterization technique, the MPBN will not introduce any extra time burden in the inference. Furthermore, the MPBN can also adopt the element-wised form, while these BNs after the convolution layer can only use the channel-wised form. Experimental results show that the proposed MPBN performs well on both popular non-spiking static and neuromorphic datasets.", + "bbox": [ + 75, + 319, + 472, + 667 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 698, + 209, + 714 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Emerged as a biology-inspired method, spiking neural networks (SNNs) have received much attention in artificial intelligence and neuroscience recently [17, 13, 57, 56, 47, 58, 59]. SNNs deal with binary event-driven spikes as their activations and therefore the multiplications of activations and weights can be substituted for additions or only keeping silent. Benefitting from such a computation paradigm, SNNs derive extreme energy efficiency and run efficiently when implemented on neuromorphic hardware [1, 42, 5].", + "bbox": [ + 75, + 724, + 468, + 861 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Despite the SNN has achieved great success in diverse fields including pattern recognition [12, 21, 19, 14], object detection [30], language processing [55], robotics [9], and so on, its development is deeply inspired by the experience of convolutional neural networks (CNNs) in many aspects. However, the spiking neuron model along with the rich spatio-temporal dynamic makes SNNs much different from CNNs, and directly transferring some experience of CNNs to SNNs without any modifications may be not a good idea. As one of the famous techniques in CNNs, the batch normalization(BN) technique shows great advantages. It can reduce the gradient exploding/vanishing problem, flatten the loss landscape, and reduce the internal covariate shift, thus being widely used in CNNs. There are also some works trying to apply normalization approaches in the SNN field to help model convergence. For example, inspired by BN in CNNs, NeuNorm [51] was proposed to normalize the data along the channel dimension. Considering that the temporal dimension is also important in SNNs, threshold-dependent batch normalization (tdBN) [62] then extended the scope of BN to the additional temporal dimension. Subsequently, to better depict the differences of data flow distributions in different time dimensions, the temporal batch normalization through time (BNTT) [31], postsynaptic potential normalization (PSP-BN) [28], and temporal effective batch normalization (TEBN) [10] that regulate the data flows with multiple BNs on different time steps were proposed.", + "bbox": [ + 500, + 287, + 893, + 710 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "However, all these BNs proposed in SNNs are advised to be used after convolution layers as usually doing in CNNs. This ignores the fact that the nonlinear transformation in the SNN spiking neuron is much more complex than that of the ReLU neuron. In the spiking neuron, the data flow after the convolution layer will be first injected into the residual membrane potential (MP) coming from the previous time step to generate a new MP at the current time step. And then the neuron will fire a spike or keep silent still based on whether or not the new MP is up to the firing threshold. Obviously, though the data flow has been normalized by the BN after the convolution layer, it will be", + "bbox": [ + 496, + 719, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Equal contribution. \n†Corresponding author, mazhe_thu@163.com.", + "bbox": [ + 94, + 875, + 341, + 900 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "19420", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/753c39a704f8c0eb5fca69152ad5cf5c19d1c3127871e3cc9636e26d81ea5f28.jpg", + "image_caption": [ + "Figure 1: The difference between our SNN with MPBN and the vanilla SNN. We add another BN layer after membrane potential updating (MPU) operation in the training. The MPBN can be folded into the firing threshold and then the homogenous firing threshold will be transformed into different ones." + ], + "image_footnote": [], + "bbox": [ + 112, + 89, + 436, + 296 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "disturbed again by the residual MP in the membrane potential updating process. Therefore, we advocate also adding a BN layer after MP updating to regulate the data flow once again, called MPBN. Furthermore, we also propose a training-inference-decoupled re-parameterization technique in SNNs to fold the trained MPBN into the firing threshold. Hence, the MPBN will not induce any extra burden in the inference but a trivial burden in the training. The MPBN can be extended to channel-wised MPBN and element-wised MPBN further, which is very different from that of CNNs where only channel-wised normalization can be folded into weights. The difference between our SNN with MPBN and the vanilla SNN is illustrated in Fig. 1. Our main contributions are as follows:", + "bbox": [ + 75, + 421, + 470, + 632 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose to add another BN layer after the membrane potential updating operation named MPBN to handle the data flow disturbance in the spiking neuron. The experiment shows that MPBN can flatten the loss landscape further, thus benefiting model convergence and task accuracy.", + "- We also propose a re-parameterization method to decouple the training-time SNN and the inference-time SNN. In specific, we propose a method to fold the trained MPBN parameter into the firing threshold. Therefore, MPBN can be seen as only training auxiliary manner free from burdens in the inference-time. This re-parameterization method is suitable for both channel-wised MPBN and element-wised MPBN.", + "- Extensive experiment results show that the SNN trained with the MPBN is highly effective compared" + ], + "bbox": [ + 94, + 642, + 470, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "with other state-of-the-art SNN models on both static and dynamic datasets, e.g., $96.47\\%$ top-1 accuracy and $79.51\\%$ top-1 accuracy are achieved on the CIFAR-10 and CIFAR-100 with only 2 time steps.", + "bbox": [ + 531, + 90, + 893, + 152 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 167, + 640, + 183 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Learning of Spiking Neural Networks", + "text_level": 1, + "bbox": [ + 500, + 191, + 825, + 209 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "There are three kinds of learning algorithms of SNNs, including unsupervised learning [43, 24], converting ANN to SNN (ANN2SNN) [46, 25, 26], and supervised learning [19, 38, 20]. Unsupervised learning adopts some biological mechanism to update the SNN model, i.e., the spiketiming-dependent plasticity (STDP) approach [39], thus being considered a biologically plausible method. However, STDP cannot help train large-scale networks yet, thus it is usually limited to small datasets and non-ideal performance. The ANN-SNN conversion approach [22, 37] obtains an SNN by reusing well-trained homogeneous ANN parameters and replacing the ReLU neuron with a spiking neuron. Since the ANN model is easier to train and reach high performance, the ANN-SNN conversion method provides an interesting way to generate an SNN in a short time with competitive performance. However, the converted SNN will lose the rich temporal dynamic behaviors and thus cannot handle neuromorphic datasets well. Supervised learning [11, 50, 18] adopts the surrogate gradient (SG) approach to train SNNs with error backpropagation. It can handle temporal data and provide decent performance with few time steps on the large-scale dataset, thus having received much attention recently. For a more detailed introduction, please refer to the recent SNN survey [17]. Our work falls under the supervised learning.", + "bbox": [ + 496, + 215, + 893, + 595 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. Normalization in Spiking Neural Networks", + "text_level": 1, + "bbox": [ + 500, + 604, + 864, + 619 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The batch normalization technique was originally introduced as a kind of training auxiliary method by [29] in CNNs. It uses the weight-summed input over a mini-batch of training cases to compute a mean and variance and then uses them to regulate the summed input. This simple operation can derive many benefits. i) It reduces the internal covariate shift (ICS), thus accelerating the training of a deep neural network. ii) It makes the network insensitive to the scale of the gradients, thus a higher learning rate can be chosen to accelerate the training. iii) It makes the network suitable for more nonlinearities by preventing the network from getting stuck in the saturated modes. With these advantages, more kinds of BNs were proposed, including layer normalization [2], group normalization [52], instance normalization [48], and switchable normalization [40].", + "bbox": [ + 496, + 628, + 890, + 853 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "There are also some works that modify and apply normalization approaches in the SNN field. For example, NeuNorm [51] also normalizes the feature map along the chan", + "bbox": [ + 496, + 854, + 893, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "19421", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "nel dimension like BN in CNNs. Recently, some methods were proposed to normalize the feature map from both the channel dimension and temporal dimension to take care of the spatio-temporal characteristics of the SNN, such as the threshold-dependent batch normalization (tdBN) [62]. It extends the scope of BN to the additional temporal dimension by adopting a 3DBN-like normalization method in CNNs. Note that, the tdBN can be folded into the weights, thus inducing no burden in the inference time. Nevertheless, NeuNorm and tdBN still use the shared parameters along the temporal dimension. Some works argued that the distributions of data in different time steps vary wildly and that using shared parameters is not a good choice. Subsequently, the temporal batch normalization through time (BNTT) [31], postsynaptic potential normalization (PSP-BN) [28], and temporal effective batch normalization (TEBN) [10] were proposed. These BNs regulate the data flow utilizing different parameters through time steps. Though these BNs with different BN parameters on different time steps can train more well-performed SNN models, their parameters can not be folded into the weights, thus will increase the computations and running time in the inference.", + "bbox": [ + 75, + 90, + 472, + 436 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Nevertheless, all these BNs in the SNN field are advised to be used after convolution layers. However, the data flow after the convolution layer will not be presented to the firing function directly but to the membrane potential updating function first. Hence, the data flow will be disturbed again before reaching the firing function. To this end, in this paper, we add another BN after the membrane potential updating function, called the MPBN to retain normalized data flow before the firing function.", + "bbox": [ + 75, + 439, + 472, + 575 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Preliminary", + "text_level": 1, + "bbox": [ + 76, + 592, + 204, + 609 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Leaky Integrate-and-Fire Model", + "text_level": 1, + "bbox": [ + 76, + 618, + 362, + 633 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Different from CNNs, SNNs use binary spikes to transmit information. In the paper, we use the widely used Leaky-Integrate-and-Fire (LIF) neuron model [41] to introduce the unique spatial-temporal dynamic of the spiking model. First, we introduce the notation rules used here as follows. Vectors or tensors are denoted by bold italic letters, i.e., $\\mathbf{x}$ and $\\mathbf{o}$ represent the input and output variables respectively. Matrices are denoted by bold capital letters. For instance, $\\mathbf{W}$ is the weight matrix. The constant is denoted by small letters.", + "bbox": [ + 75, + 642, + 468, + 792 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In LIF, the membrane potential is updated by", + "bbox": [ + 96, + 795, + 395, + 810 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {u} ^ {(t + 1), \\text {p r e}} = \\tau \\boldsymbol {u} ^ {(t)} + \\boldsymbol {c} ^ {(t + 1)}, \\text {w h e r e} \\boldsymbol {c} ^ {(t + 1)} = \\mathbf {W} \\boldsymbol {x} ^ {(t + 1)}, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 89, + 821, + 468, + 854 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\pmb{u}$ represents the membrane potential and $\\pmb{u}^{(t + 1),\\mathrm{pre}}$ is the updated membrane potential at time step $t + 1$ , $\\pmb{c}^{(t + 1)}$ is the pre-synaptic input at time step $t + 1$ , which is charged", + "bbox": [ + 75, + 854, + 468, + 901 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "by weight-summed input spikes $\\pmb{x}^{(t + 1)}$ , and $\\tau$ is a constant within (0, 1), which controls the leakage of the membrane potential. Then, when the updated membrane potential $\\pmb{u}^{(t + 1),\\mathrm{pre}}$ is up to the firing threshold $V_{\\mathrm{th}}$ , the LIF spiking neuron will fire a spike as below,", + "bbox": [ + 496, + 90, + 890, + 167 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {o} ^ {(t + 1)} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f} \\boldsymbol {u} ^ {(t + 1), \\text {p r e}} > V _ {\\text {t h}} \\\\ 0 & \\text {o t h e r w i s e} \\end{array} , \\right. \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 576, + 179, + 890, + 219 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {u} ^ {(t + 1)} = \\boldsymbol {u} ^ {(t + 1), \\text {p r e}} \\cdot (1 - \\boldsymbol {o} ^ {(t + 1)}).\n$$\n", + "text_format": "latex", + "bbox": [ + 581, + 222, + 813, + 241 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "After firing, the spike output $\\pmb{o}^{(t + 1)}$ at time step $t + 1$ will be transmitted to the next layer and become its input. At the same time, the updated membrane potential will be reset to zero and becomes $\\pmb{u}^{(t + 1)}$ to join the neuron processing at the next time step.", + "bbox": [ + 496, + 255, + 890, + 330 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The Classifier in the SNN. In a classification model, the final output is used to compute the Softmax and predict the desired class object. In an SNN model, if we also use LIF neurons at the output layer to fire spikes and use the number of spikes to compute the probability, too much information will be lost. Therefore, we only integrate the output and do not fire them across time, as doing in recent work [20, 21, 12].", + "bbox": [ + 496, + 333, + 890, + 453 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {o} _ {\\text {o u t}} = \\frac {1}{T} \\sum_ {t = 1} ^ {T} \\boldsymbol {c} _ {\\text {o u t}} ^ {(t)} = \\frac {1}{T} \\sum_ {t = 1} ^ {T} \\mathbf {W} \\boldsymbol {x} ^ {(t)}. \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 576, + 455, + 890, + 496 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Then, the cross-entropy loss is computed based on the true label and $\\operatorname{Softmax}(\\pmb{o}_{\\mathrm{out}})$ .", + "bbox": [ + 496, + 503, + 890, + 535 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Batch Normalization in SNNs", + "text_level": 1, + "bbox": [ + 500, + 547, + 764, + 561 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Batch normalization can effectively reduce the internal covariate shift and alleviate the gradient vanishing or explosion problem for training networks, thus having been widely used in CNNs. Fortunately, BN can also be used in SNNs. Considering a spiking neuron with input $\\pmb{c} = \\{c^{(1)}, c^{(2)}, \\dots, c^{(t)}, \\dots\\}$ , where $t$ is the time step, BN regulate the input at each time step as follows,", + "bbox": [ + 496, + 571, + 890, + 678 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\tilde {\\boldsymbol {c}} _ {i} ^ {(t)} = \\frac {\\boldsymbol {c} _ {i} ^ {(t)} - \\boldsymbol {\\mu} _ {i}}{\\sqrt {\\boldsymbol {\\sigma} _ {i} ^ {2} + \\epsilon}}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 633, + 690, + 890, + 729 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $c_{i}^{(t)}$ is the input in $i$ -th channel at $t$ -th time step, $\\mu_{i}$ and $\\sigma_{i}$ are the mean and variance of input in channel dimension, and $\\epsilon$ is a small constant to avoid denominator being zero. To ensure BN can represent the identity transformation, the normalized vector $\\tilde{c}_{i}^{(t)}$ is scaled and shifted in a learning manner as follows,", + "bbox": [ + 496, + 743, + 890, + 839 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\operatorname {B N} \\left(\\boldsymbol {c} _ {i} ^ {(t)}\\right) = \\boldsymbol {\\lambda} _ {i} \\tilde {\\boldsymbol {c}} _ {i} ^ {(t)} + \\boldsymbol {\\beta} _ {i}, \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 611, + 851, + 890, + 872 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\lambda_{i}$ and $\\beta_{i}$ are channel-wised learnable parameters.", + "bbox": [ + 500, + 885, + 877, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "19422", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4. Methodology", + "text_level": 1, + "bbox": [ + 76, + 89, + 210, + 107 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "This section first introduces the specific form of membrane potential batch normalization. Then the reparameterization technique that how to fold the MPBN into $V_{\\mathrm{th}}$ will be introduced in detail. Next, some key details for training the SNN and the pseudocode for the training and inference of our SNN will be given. Finally, we will provide plenty of ablation studies and the comparison of the loss landscape of the models with or without MPBN to show the effectiveness of the proposed method.", + "bbox": [ + 75, + 114, + 472, + 251 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Membrane Potential Batch Normalization", + "text_level": 1, + "bbox": [ + 76, + 258, + 436, + 273 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "As abovementioned, we argue that though the data flow has been normalized by the BN after the convolution layer, it will be disturbed again by the membrane potential updating operation. To better depict this, we give the vanilla form of LIF neuron with BN first as follows,", + "bbox": [ + 75, + 282, + 468, + 357 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {u} ^ {(t + 1), \\text {p r e}} = \\tau \\boldsymbol {u} ^ {(t)} + \\mathrm {B N} (\\mathbf {W} \\boldsymbol {x} ^ {(t + 1)}), \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 148, + 364, + 468, + 383 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\tau$ is 0.25 in the paper following [21, 38, 4]. To regulate the disturbed data flow once again, We further embed another BN after the membrane potential updating operation, called MPBN. The LIF neuron with MPBN can be updated as", + "bbox": [ + 75, + 392, + 468, + 465 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\tilde {\\boldsymbol {u}} ^ {(t + 1), \\text {p r e}} = \\operatorname {M P B N} (\\boldsymbol {u} ^ {(t + 1), \\text {p r e}}). \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 163, + 465, + 468, + 484 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Obviously, $\\pmb{u}^{(t + 1),\\mathrm{pre}}$ will be scaled and sifted, and some $\\pmb{u}^{(t + 1),\\mathrm{pre}}$ less than $V_{\\mathrm{th}}$ may be greater than $V_{\\mathrm{th}}$ with MPBN and vice versa. This is abhorrent with the biology and MPBN will cause some extra computation burden in the inference compared with the vanilla one. To solve this problem, we also propose a training-inference-decoupled re-parameterization technique here.", + "bbox": [ + 75, + 487, + 468, + 594 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.2. Re-parameterization", + "text_level": 1, + "bbox": [ + 76, + 602, + 272, + 617 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "With MPBN, the firing function will be updated as", + "bbox": [ + 96, + 625, + 431, + 641 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {o} ^ {(t + 1)} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f M P B N} (\\boldsymbol {u} ^ {(t + 1), \\text {p r e}}) > V _ {\\text {t h}} \\\\ 0 & \\text {o t h e r w i s e} \\end{array} . \\right. \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 122, + 647, + 468, + 689 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "If we unfold the MPBN, the above equation will be reorganized as", + "bbox": [ + 75, + 695, + 468, + 724 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {o} _ {i} ^ {(t + 1)} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f} \\lambda_ {i} \\frac {\\boldsymbol {u} _ {i} ^ {(t + 1) , \\text {p r e}} - \\boldsymbol {\\mu} _ {i}}{\\sqrt {\\sigma_ {i} ^ {2}}} + \\beta_ {i} > V _ {\\text {t h}} \\\\ 0 & \\text {o t h e r w i s e} \\end{array} . \\right. \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 117, + 733, + 468, + 781 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "By folding the MPBN to $V_{\\mathrm{th}}$ , the firing function will be further updated as", + "bbox": [ + 75, + 789, + 468, + 819 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {o} _ {i} ^ {(t + 1)} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f} \\boldsymbol {u} ^ {(t + 1), \\text {p r e}} > \\left(\\tilde {\\boldsymbol {V}} _ {\\mathrm {t h}}\\right) _ {i} \\\\ 0 & \\text {o t h e r w i s e} \\end{array} , \\right. \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 148, + 827, + 468, + 872 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $(\\tilde{V}_{\\mathrm{th}})_i = \\frac{(V_{\\mathrm{th}} - \\beta_i)\\sqrt{\\sigma_i^2}}{\\lambda_i} +\\pmb {\\mu}_i$", + "bbox": [ + 140, + 872, + 403, + 904 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Algorithm 1 Training and inference of our SNN.", + "bbox": [ + 500, + 90, + 825, + 104 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Training", + "text_level": 1, + "bbox": [ + 500, + 108, + 566, + 122 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Input: An SNN to be trained with MPBN; training dataset; total training iteration: $I_{\\text{train}}$ .", + "bbox": [ + 500, + 123, + 890, + 152 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Output: The well-trained SNN.", + "bbox": [ + 500, + 152, + 712, + 167 + ], + "page_idx": 3 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1: for all $i = 1,2,\\ldots ,{I}_{\\text{train }}$ iteration do", + "2: Get mini-batch training data, $\\pmb{x}_{\\mathrm{in}}(i)$ and class label, $\\pmb{y}(i)$ ;", + "3: Feed the $\\pmb{x}_{\\mathrm{in}}(i)$ into the SNN and regulate the data flow by BN and MPBN;", + "4: Calculate the SNN output, $\\pmb{o}_{\\mathrm{out}}(i)$ by Eq. 3;", + "5: Compute classification loss $L_{\\mathrm{CE}}$ = $\\mathcal{L}_{\\mathrm{CE}}(\\pmb{o}_{\\mathrm{out}}(i),\\pmb{y}(i));$", + "6: Calculate the gradient w.r.t. W by Eq. 11;", + "7: Update $\\mathbf{W}$ : $(\\mathbf{W} \\leftarrow \\mathbf{W} - \\eta \\frac{\\partial L}{\\partial \\mathbf{W}})$ where $\\eta$ is learning rate.", + "8: end for" + ], + "bbox": [ + 509, + 170, + 890, + 349 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Re-parameterization", + "text_level": 1, + "bbox": [ + 500, + 354, + 648, + 368 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Input: The trained SNN with MPBN; total number of MPBN: $n$ .", + "bbox": [ + 500, + 369, + 890, + 397 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Output: The re-parameterized trained SNN without MPBN but diverse $V_{\\mathrm{th}}$ .", + "bbox": [ + 500, + 398, + 890, + 429 + ], + "page_idx": 3 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1: for all $i = 1,2,\\ldots ,n$ number do", + "2: Fold the parameters of $i$ -th MPBN into $i$ -th $V_{\\mathrm{th}}$ by Eq. 10;", + "3: end for" + ], + "bbox": [ + 509, + 431, + 890, + 489 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Inference", + "text_level": 1, + "bbox": [ + 500, + 494, + 571, + 507 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Input: The re-parameterized trained SNN; test dataset; total test iteration: $I_{\\mathrm{test}}$ .", + "bbox": [ + 500, + 510, + 890, + 540 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Output: The output.", + "bbox": [ + 500, + 541, + 638, + 555 + ], + "page_idx": 3 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "1: for all $i = 1,2,\\ldots ,{I}_{\\text{test }}$ iteration do", + "2: Get mini-batch test data, $\\mathbf{x}_{\\mathrm{in}}(i)$ and class label, $\\mathbf{y}(i)$ in test dataset;", + "3: Feed the $\\pmb{x}_{\\mathrm{in}}(i)$ into the reparameterized SNN without MPBN;", + "4: Calculate the SNN output, $\\pmb{o}_{\\mathrm{out}}(i)$ by Eq. 3;", + "5: Compare the classification factor $\\pmb{o}_{\\mathrm{out}}(i)$ and $\\pmb{y}(i)$ for classification." + ], + "bbox": [ + 509, + 558, + 888, + 676 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "6: end for", + "text_level": 1, + "bbox": [ + 509, + 679, + 581, + 691 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "It can be seen that by absorbing some parameters from MPBN, $V_{\\mathrm{th}}$ will be transformed to another channel-wised $(\\tilde{V}_{\\mathrm{th}})_i$ . In this way, the extra computation burden caused by MPBN will be eliminated again in the inference time. Furthermore, the diversity of the spiking neuron will be improved with abundant firing parameters as the learnable firing threshold in other work [3, 49].", + "bbox": [ + 496, + 724, + 890, + 830 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.3. Training Framework", + "text_level": 1, + "bbox": [ + 500, + 845, + 697, + 861 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In the paper, the spatial-temporal backpropagation (STBP) algorithm [51] is adopted to train the SNN mod", + "bbox": [ + 500, + 869, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "19423", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/7dc6ade33d1190bb6aa0db95652147e83bc5f7dcd28ced2428a6446947c4bdb7.jpg", + "image_caption": [ + "(a) CIFAR-10" + ], + "image_footnote": [], + "bbox": [ + 86, + 94, + 256, + 196 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/9532ddd02be7274b71ff4db54919280bc180d4795662696cb7b42e6d766f2355.jpg", + "image_caption": [ + "(b) CIFAR-100", + "Figure 2: The accuracy curves of spiking ResNet20 with or without MPBN using 2 time steps on CIFAR-10 (left) and CIFAR-100 (right). The MPBN based SNNs obviously enjoy higher accuracy and easier convergence." + ], + "image_footnote": [], + "bbox": [ + 279, + 95, + 444, + 196 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "els. STBP treats the SNN model as a self-recurrent neural network thus enabling an error backpropagation mechanism following the same principles as in CNNs. However, there is still a problem impeding the direct training of SNNs. To demonstrate this problem, we formulate the gradient at the layer $l$ by the chain rule, given by", + "bbox": [ + 75, + 318, + 468, + 409 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\frac {\\partial L}{\\partial \\mathbf {W} ^ {l}} = \\sum_ {t} \\left(\\frac {\\partial L}{\\partial \\boldsymbol {o} ^ {(t) , l}} \\frac {\\partial \\boldsymbol {o} ^ {(t) , l}}{\\partial \\boldsymbol {u} ^ {(t) , l}} + \\frac {\\partial L}{\\partial \\boldsymbol {u} ^ {(t + 1) , l}} \\frac {\\partial \\boldsymbol {u} ^ {(t + 1) , l}}{\\partial \\boldsymbol {u} ^ {(t) , l}}\\right) \\frac {\\partial \\boldsymbol {u} ^ {(t) , l}}{\\partial \\mathbf {W} ^ {l}}, \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 76, + 421, + 468, + 470 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\frac{\\partial\\pmb{o}^{(t),l}}{\\partial\\pmb{u}^{(t),l}}$ is the gradient of firing function at at $t$ -th time step in $l$ -th layer. Obviously, the non-differentiable firing activity of the spiking neuron will result in zero gradients everywhere, while infinity at $V_{\\mathrm{th}}$ . Therefore, the gradient descent $(\\mathbf{W}^l\\gets \\mathbf{W}^l -\\eta \\frac{\\partial L}{\\partial\\mathbf{W}^l})$ either freezes or updates to infinity in the backpropagation. To handle this problem, here, we also adopt the commonly used STE surrogate gradients as doing in other surrogate gradients (SG) methods [44, 20]. Mathematically, it is defined as:", + "bbox": [ + 75, + 472, + 468, + 609 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\frac {d \\boldsymbol {o}}{d \\boldsymbol {u}} = \\left\\{ \\begin{array}{l l} 1, & \\text {i f} 0 \\leq \\boldsymbol {u} \\leq 1 \\\\ 0, & \\text {o t h e r w i s e} \\end{array} \\right.. \\tag {12}\n$$\n", + "text_format": "latex", + "bbox": [ + 156, + 623, + 468, + 656 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Then, the SNN model can be trained end-to-end. The training and inference of our SNN are detailed in Algo. 1.", + "bbox": [ + 76, + 667, + 468, + 698 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.4. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 710, + 228, + 726 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To verify the effectiveness of the MPBN, a lot of ablative studies using spiking ResNet20 architecture along with different time steps were conducted on the CIFAR-10 and CIFAR-100 datasets. The results of top-1 accuracy of these models are shown in Tab. 1. It's can be seen that the test accuracy of the SNNs with MPBN is always higher than these vanilla counterparts. For example, the accuracy of baseline SNN with 1 time step is $90.40\\%$ , while with MPBN, it will increase up to $92.22\\%$ , which is a huge improvement (more than $2.0\\%$ ) in the SNN field. Moreover, we also show the test accuracy curves of ResNet20 using MPBN and its", + "bbox": [ + 75, + 734, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/6f0f77407c2aca89fdc1b019e0b3bf428daa18301e81702c2981fa7afb370203.jpg", + "table_caption": [ + "Table 1: Ablation experiments for MPBN." + ], + "table_footnote": [], + "table_body": "
DatasetMethodTime stepAccuracy
CIFAR-10baseline190.40%
w/ MPBN192.22%
baseline292.80%
w/ MPBN293.54%
baseline493.85%
w/ MPBN494.28%
CIFAR-100baseline167.94%
w/ MPBN168.36%
baseline270.18%
w/ MPBN270.79%
baseline471.77%
w/ MPBN472.30%
", + "bbox": [ + 519, + 114, + 874, + 325 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/6863b9ac56d0690ab487204ebbbc6ece166455ad1ad0c842df883d19db9f0313.jpg", + "image_caption": [ + "(a) MPBN", + "Figure 3: The 1D loss landscape of spiking ResNet20 with and without MPBN." + ], + "image_footnote": [], + "bbox": [ + 509, + 340, + 692, + 434 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/5e6dea99328c8638d89687bd97a184f1994ea19a3d6e40db450ad2569f5c2e5e.jpg", + "image_caption": [ + "(b) Vanilla" + ], + "image_footnote": [], + "bbox": [ + 702, + 340, + 883, + 434 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "vanilla counterpart with 2 time steps on CIFAR-10/100 during training in Fig. 2. It can be observed obviously that the SNNs with MPBN also perform better on convergence speed. To sum up, the proposed MPBN can both improve accuracy and convergence speed, which are very important aspects in deep learning.", + "bbox": [ + 498, + 526, + 890, + 617 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.5. Loss Landscape", + "text_level": 1, + "bbox": [ + 500, + 626, + 658, + 643 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We further inspect the 1D loss landscapes [36] of the SNNs with or without MPBN using spiking ResNet20 architecture in 2 time steps to show why the MPBN can improve accuracy and convergence speed in Fig. 3. It can be observed that the loss landscape of the SNN model with MPBN is flatter than that of the SNN without MPBN. This indicates that the MPBN makes the landscape of the corresponding optimization problem smoother [36], thus making the gradients more predictive and network faster convergence. The results here provide convincing evidence for ablation studies in Section 4.4.", + "bbox": [ + 498, + 648, + 890, + 815 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 500, + 830, + 632, + 847 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In this section, abundant experiments were conducted to verify the effectiveness of the MPBN using widely-used spiking ResNet20 [44, 46], VGG16 [44], ResNet18 [11],", + "bbox": [ + 498, + 854, + 890, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "19424", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/588ccc23c9aad74dcdf1526efc833a637967f1adfed9d739bdca805b17c47303.jpg", + "table_caption": [ + "Table 2: Comparison with SoTA methods on CIFAR-10." + ], + "table_footnote": [], + "table_body": "
DatasetMethodTypeArchitectureTimestepAccuracy
CIFAR-10SpikeNorm [46]ANN2SNNVGG16250091.55%
Hybrid-Train [45]Hybrid trainingVGG1620092.02%
Spike-basedBP [34]SNN trainingResNet1110090.95%
Joint A-SNN [19]SNN trainingResNet18495.45%
GLIF [60]SNN trainingResNet19294.44%
PLIF [12]SNN trainingPLIFNet893.50%
Diet-SNN [44]SNN trainingVGG16592.70%
1093.44%
ResNet20591.78%
1092.54%
RecDis-SNN [20]SNN trainingResNet19293.64%
495.53%
695.55%
Dspike [38]SNN trainingResNet20293.13%
493.66%
694.25%
STBP-tdBN [62]SNN trainingResNet19292.34%
492.92%
693.16%
TET [7]SNN trainingResNet19294.16%
494.44%
694.50%
Real Spike [21]SNN trainingResNet19295.31%
495.51%
696.10%
InfLoR-SNN [16]SNN trainingResNet20593.01%
1093.65%
MPBNSNN trainingResNet19196.06%±0.10
296.47%±0.08
ResNet20192.22%±0.11
293.54%±0.09
494.28%±0.07
VGG16293.96%±0.09
494.44%±0.08
", + "bbox": [ + 156, + 114, + 816, + 660 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "ResNet19 [62], and ResNet34 [11] on both static datasets including CIFAR-10 [32], CIFAR-100 [32], and ImageNet [6], and one neuromorphic dataset, CIFAR10-DVS [35]. The specific introduction for these datasets has been detailed in many recent works [62, 44, 21, 38]. Here, we mainly introduce these hyper-parameters and data preprocessing in detail. We used the widely adopted LIF neuron in our SNN models as other works about direct training methods [44, 46]. These hyper-parameters for LIF neuron about the initial firing threshold $V_{\\mathrm{th}}$ and the membrane potential decaying constant $\\tau_{\\mathrm{decay}}$ are 0.5 and 0.25 respectively. For static image datasets, since encoding the 8-bit RGB images into 1-bit spikes will lose too much information, we use an ANN-like convolutional layer and a LIF layer to encode the", + "bbox": [ + 75, + 684, + 472, + 897 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "images to spikes for all the rest of the layers, as in recent works [62, 44, 21, 38].", + "bbox": [ + 498, + 684, + 890, + 714 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Comparison with SoTA Methods", + "text_level": 1, + "bbox": [ + 498, + 724, + 789, + 742 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "CIFAR-10. On CIFAR-10, we trained our SNN model using the SGD optimizer with 0.9 momentum. The initial learning rate is 0.1 and decays to 0 in cosine form. The total training time is 400 epochs. To fairly compare with these recent SoTA methods [38, 20, 16], we also adopt data normalization, random horizontal flipping, cropping, and cutout [8] for data augmentation. We run three times for each experiment to report the \"mean ± std\" in Tab. 2. It can be seen that our models can outperform other methods over all these chosen widely adopted architectures with", + "bbox": [ + 496, + 750, + 893, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "19425", + "bbox": [ + 480, + 944, + 517, + 957 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/546326ffe740b108e04f1bdd8ae06bebe5901e2592bea9f1b6328201acdfbd66.jpg", + "table_caption": [ + "Table 3: Comparison with SoTA methods on CIFAR-100." + ], + "table_footnote": [], + "table_body": "
DatasetMethodTypeArchitectureTimestepAccuracy
CIFAR-100SpikeNorm [46]ANN2SNNResNet20250064.09%
RMP [23]ANN2SNNResNet20204867.82%
Hybrid-Train [45]Hybrid trainingVGG1112567.90%
IM-Loss [15]SNN trainingVGG16570.18%
Joint A-SNN [19]SNN trainingResNet18477.39%
ResNet34479.76%
Dspike [38]SNN trainingResNet20271.68%
473.35%
674.24%
TET [7]SNN trainingResNet19272.87%
474.47%
674.72%
RecDis-SNN [20]SNN trainingResNet19474.10%
VGG16569.88%
InfLoR-SNN [16]SNN trainingResNet20571.19%
VGG16571.56%
Real Spike [21]SNN trainingResNet20566.60%
VGG16570.62%
GLIF [60]SNN trainingResNet19275.48%
477.05%
TEBN [10]SNN trainingResNet19275.86%
476.13%
676.41%
MPBNSNN trainingVGG16474.74%±0.11
ResNet19178.71%±0.10
279.51%±0.07
ResNet20270.79%±0.08
472.30%±0.08
", + "bbox": [ + 158, + 114, + 810, + 568 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/85a3e33687344eab1d6bdedec19f703bad42504dd32e4baba3e5792c1d762461.jpg", + "table_caption": [ + "Table 4: Comparison with SoTA methods on ImageNet." + ], + "table_footnote": [], + "table_body": "
DatasetMethodTypeArchitectureTimestepAccuracy
ImageNetSTBP-tdBN [62]SNN trainingResNet34663.72%
TET [7]SNN trainingResNet34664.79%
MS-ResNet [27]SNN trainingResNet18663.10%
OTT [54]SNN trainingResNet34663.10%
Real Spike [21]SNN trainingResNet18463.68%
SEW ResNet [11]SNN trainingResNet18463.18%
ResNet34467.04%
MPBNSNN trainingResNet18463.14%±0.08
ResNet34464.71%±0.09
", + "bbox": [ + 171, + 608, + 799, + 773 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "fewer time steps. For example, The accuracy of spiking ResNet19 trained with MPBN with only 1 time step can be up to $96.06\\%$ , while the Real Spike [21] needs 6 time steps to reach a comparable result and the RecDis-SNN [61] even still underperforms $0.51\\%$ with 6 time steps. This superiority can also be observed in the results regarding the spiking", + "bbox": [ + 75, + 799, + 470, + 891 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "ResNet20 and VGG16.", + "bbox": [ + 500, + 799, + 656, + 813 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "CIFAR-100. For CIFAR-100, we adopted the same settings as in CIFAR-10. The proposed MPBN also performs well on CIFAR-100. It can be seen that our method gets the best accuracy over all these networks even with fewer time steps. For instants, the ResNet19 trained with MPBN", + "bbox": [ + 496, + 824, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "19426", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/071584ea156ed8f7f9430a0a5a67f61e32c6d8cee608a8a8cde4de1280f7fde7.jpg", + "table_caption": [ + "Table 5: Comparison with SoTA methods on CIFAR10-DVS." + ], + "table_footnote": [], + "table_body": "
DatasetMethodTypeArchitectureTimestepAccuracy
CIFAR10-DVSRollout [33]RolloutDenseNet1066.80%
LIAF-Net [53]Conv3DLIAF-Net1071.70%
LIAF-Net [53]LIAFLIAF-Net1070.40%
STBP-tdBN [62]SNN trainingResNet191067.80%
RecDis-SNN [20]SNN trainingResNet191072.42%
Real Spike [21]SNN trainingResNet191072.85%
ResNet201078.00%
MPBNSNN trainingResNet191074.40%±0.20
ResNet201078.70%±0.10
", + "bbox": [ + 153, + 114, + 818, + 282 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "can achieve $78.71\\%$ top-1 accuracy with only 1 time step, which outperforms other SoTA methods such as TET, GLIF, TEBN, and RecDis-SNN even with 4 or 6 time steps about $1.66\\% -3.99\\%$ .", + "bbox": [ + 75, + 306, + 468, + 366 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "ImageNet. On ImageNet, we used standard data normalization, random horizontal flipping, and cropping for data augmentation and trained the networks for 320 epochs as in [11]. The optimizer setting also keeps the same with CIFAR datasets. The results for ImageNet are presented in Tab. 4. It can be seen that the accuracy of our method is better than that of these recent SoTA methods, only relatively smaller compared with SEW ResNet [11] for spiking ResNet34. However, SEW ResNet is not a typical SNN model. It adopts the activation before addition form-based ResNet and its blocks will fire positive integer spikes. In this way, the event-driven and multiplication-addition transform advantages of SNNs will be lost. While we adopt the original ResNet, which fires standard binary spikes.", + "bbox": [ + 75, + 367, + 468, + 578 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "CIFAR10-DVS. We also adopted the neuromorphic dataset, CIFAR10-DVS in the paper to verify the effectiveness of the MPBN. We also split the dataset into 9K training images and 1K test images, and resize them to $48 \\times 48$ for data augmentation as in [51, 21]. The learning rate is 0.01 and other settings are the same as CIFAR-10. It can be seen that the MPBN also shows superiority in this dataset.", + "bbox": [ + 75, + 579, + 468, + 685 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.2. Extension of the MPBN", + "text_level": 1, + "bbox": [ + 76, + 693, + 302, + 708 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In CNNs, the most widely used BN is channelwised. This is because element-wised BNs are very time-consuming and can not be folded into weights, otherwise, the channel-wised weight-sharing mechanism will be destroyed. However, the MPBN adopts the firing thresholdfolded manner and the firing threshold need not keep the same along the channels, therefore, MPBN can use the element-wised form freely. In this way, $V_{\\mathrm{th}}$ will be transformed to element-wised ones as follows,", + "bbox": [ + 75, + 715, + 468, + 852 + ], + "page_idx": 7 + }, + { + "type": "equation", + "text": "\n$$\n(\\tilde {\\boldsymbol {V}} _ {\\mathrm {t h}}) _ {i, j, k} = \\frac {(V _ {\\mathrm {t h}} - \\beta_ {i , j , k}) \\sqrt {\\sigma_ {i , j , k} ^ {2}}}{\\boldsymbol {\\lambda} _ {i , j , k}} + \\boldsymbol {\\mu} _ {i, j, k}, \\tag {13}\n$$\n", + "text_format": "latex", + "bbox": [ + 109, + 861, + 468, + 905 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/207bdb3c0906f30b6aeefabaac5408db75f35a71e099b57775946db7d928fe93.jpg", + "table_caption": [ + "Table 6: Comparison with learnable firing threshold methods." + ], + "table_footnote": [], + "table_body": "
DatasetMethodTime stepAccuracy
CIFAR-10channel-wised494.28%
element-wised494.42%
CIFAR-100channel-wised472.30%
element-wised472.49%
", + "bbox": [ + 504, + 345, + 887, + 438 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "where $(\\tilde{V}_{\\mathrm{th}})_{i,j,k}$ is the transformed firing threshold of the neuron comes from $i$ -th channel in the spatial position $(j,k)$ . To investigate the performance of the element-wised MPBN, here we also provide a comparison of the vanilla MPBN and its extension. The results of top-1 accuracy of the spiking ResNet20 with 4 time steps on CIFAR datasets are shown in Tab. 6. Though the two versions all perform well, the element-wised MPBN is relatively better than the channel-wised MPBN. This may be because element-wised MPBN can learn more firing threshold values, which means a richer representation ability for SNNs.", + "bbox": [ + 496, + 460, + 890, + 628 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 640, + 619, + 656 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In the paper, we advocated adding the MPBN before the firing function to regulate the disturbed data flow again. We also provided a training-inference-decoupled reparameterization technique to fold the trained MPBN into the firing threshold to eliminate the extra time burden induced by MPBN in the inference time. Furthermore, the channel-wised and element-wised MPBN in different granularities were explored. Extensive experiments verified that the proposed MPBN can consistently achieve good performance.", + "bbox": [ + 496, + 665, + 890, + 816 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgment", + "text_level": 1, + "bbox": [ + 500, + 830, + 651, + 847 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "This work is supported by grants from the National Natural Science Foundation of China under contracts No.12202412 and No.12202413.", + "bbox": [ + 498, + 854, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "19427", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 174, + 106 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Filipp Akopyan, Jun Sawada, Andrew Cassidy, Rodrigo Alvarez-Icaza, John Arthur, Paul Merolla, Nabil Imam, Yutaka Nakamura, Pallab Datta, Gi-Joon Nam, Brian Taba, Michael Beakes, Bernard Brezzo, Jente Kuang, Rajit Manohar, W.P. Risk, Bryan Jackson, and Dharmendra Modha. Truenorth: Design and tool flow of a 65 mw 1 million neuron programmable neurosynaptic chip. Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on, 34:1537-1557, 10 2015. 1", + "[2] Jimmy Lei Ba, Jamie Ryan Kiros, and Geoffrey E Hinton. Layer normalization. arXiv preprint arXiv:1607.06450, 2016. 2", + "[3] G. Bellec, D. Salaj, A. Subramoney, R. Legenstein, and W. Maass. Long short-term memory and learning-to-learn in networks of spiking neurons, 2018. 4", + "[4] Xiang Cheng, Yunzhe Hao, Jiaming Xu, and Bo Xu. Lisnn: Improving spiking neural networks with lateral interactions for robust object recognition. pages 1519-1525, 07 2020. 4", + "[5] Mike Davies, Narayan Srinivasa, Tsung-Han Lin, Gautham Chinya, Andrew Lines, Andreas Wild, Hong Wang, and Deepak Mathaikutty. Loihi: A neuromorphic manycore processor with on-chip learning. IEEE Micro, 38:82 - 99, 01 2018. 1", + "[6] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Fei-Fei Li. Imagenet: a large-scale hierarchical image database. pages 248-255, 06 2009. 6", + "[7] Shikuang Deng, Yuhang Li, Shanghang Zhang, and Shi Gu. Temporal efficient training of spiking neural network via gradient re-weighting. In International Conference on Learning Representations, 2022. 6, 7", + "[8] Terrance DeVries and Graham W. Taylor. Improved regularization of convolutional neural networks with cutout, 2017. 6", + "[9] Travis DeWolf. Spiking neural networks take control. Science Robotics, 6(58):eabk3268, 2021. 1", + "[10] Chaoteng Duan, Jianhao Ding, Shiyan Chen, Zhaofei Yu, and Tiejun Huang. Temporal effective batch normalization in spiking neural networks. In Alice H. Oh, Alekh Agarwal, Danielle Belgrave, and Kyunghyun Cho, editors, Advances in Neural Information Processing Systems, 2022. 1, 3, 7", + "[11] Wei Fang, Zhaofei Yu, Yanqi Chen, Tiejun Huang, and Yonghong Tian. Deep residual learning in spiking neural networks. 2021. 2, 5, 6, 7, 8", + "[12] Wei Fang, Zhaofei yu, Yanqi Chen, Timothee Masquelier, Tiejun Huang, and Yonghong Tian. Incorporating learnable membrane time constant to enhance learning of spiking neural networks. 08 2021. 1, 3, 6", + "[13] Samanwoy Ghosh-Dastidar and Hojjat Adeli. Spiking neural networks. Int. J. Neural Syst., 19:295-308, 08 2009. 1", + "[14] Yufei Guo and Yuanpei Chen. Neuroclip: Neuromorphic data understanding by clip and snn. arXiv preprint arXiv:2306.12073, 2023. 1", + "[15] Yufei Guo, Yuanpei Chen, Liwen Zhang, Xiaode Liu, Yinglei Wang, Xuhui Huang, and Zhe Ma. IM-loss: Information maximization loss for spiking neural networks. In Alice H." + ], + "bbox": [ + 78, + 114, + 468, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Oh, Alekh Agarwal, Danielle Belgrave, and Kyunghyun Cho, editors, Advances in Neural Information Processing Systems, 2022. 7", + "[16] Yufei Guo, Yuanpei Chen, Liwen Zhang, YingLei Wang, Xiaode Liu, Xinyi Tong, Yuanyuan Ou, Xuhui Huang, and Zhe Ma. Reducing information loss for spiking neural networks. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XI, pages 36-52. Springer, 2022. 6, 7", + "[17] Yufei Guo, Xuhui Huang, and Zhe Ma. Direct learning-based deep spiking neural networks: a review. Frontiers in Neuroscience, 17:1209795, 2023. 1, 2", + "[18] Yufei Guo, Xiaode Liu, Yuanpei Chen, Liwen Zhang, Wei-hang Peng, Yuhan Zhang, Xuhui Huang, and Zhe Ma. Rmp-loss: Regularizing membrane potential distribution for spiking neural networks. arXiv preprint arXiv:2308.06787, 2023.2", + "[19] Yufei Guo, Weihang Peng, Yuanpei Chen, Liwen Zhang, Xiaode Liu, Xuhui Huang, and Zhe Ma. Joint a-snn: Joint training of artificial and spiking neural networks via self-distillation and weight factorization. Pattern Recognition, page 109639, 2023. 1, 2, 6, 7", + "[20] Yufei Guo, Xinyi Tong, Yuanpei Chen, Liwen Zhang, Xiaode Liu, Zhe Ma, and Xuhui Huang. Recdis-snn: Rectifying membrane potential distribution for directly training spiking neural networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 326-335, June 2022. 2, 3, 5, 6, 7, 8", + "[21] Yufei Guo, Liwen Zhang, Yuanpei Chen, Xinyi Tong, Xiaode Liu, YingLei Wang, Xuhui Huang, and Zhe Ma. Real spike: Learning real-valued spikes for spiking neural networks. In European Conference on Computer Vision, pages 52-68. Springer, 2022. 1, 3, 4, 6, 7, 8", + "[22] Bing Han and Kaushik Roy. Deep spiking neural network: Energy efficiency through time based coding. In ECCV, pages 388-404. Springer, 2020. 2", + "[23] Bing Han, Gopalakrishnan Srinivasan, and Kaushik Roy. Rmp-snn: Residual membrane potential neuron for enabling deeper high-accuracy and low-latency spiking neural network. pages 13555–13564, 06 2020. 7", + "[24] Yunzhe Hao, Xuhui Huang, Meng Dong, and Bo Xu. A biologically plausible supervised learning method for spiking neural networks using the symmetric stdp rule. Neural Networks, 121, 09 2019. 2", + "[25] Zecheng Hao, Tong Bu, Jianhao Ding, Tiejun Huang, and Zhaofei Yu. Reducing ann-snn conversion error through residual membrane potential, 2023. 2", + "[26] Zecheng Hao, Jianhao Ding, Tong Bu, Tiejun Huang, and Zhaofei Yu. Bridging the gap between anns and snns by calibrating offset spikes, 2023. 2", + "[27] Yifan Hu, Yujie Wu, Lei Deng, and Guoqi Li. Advancing residual learning towards powerful deep spiking neural networks. arXiv preprint arXiv:2112.08954, 2021. 7", + "[28] Shin-ichi Ikegawa, Ryuji Saiin, Yoshihide Sawada, and Naotake Natori. Rethinking the role of normalization and residual blocks for spiking neural networks. Sensors, 22(8), 2022. 1, 3" + ], + "bbox": [ + 503, + 92, + 890, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "19428", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[29] Sergey Ioffe and Christian Szegedy. Batch normalization: Accelerating deep network training by reducing internal covariate shift. In International conference on machine learning, pages 448-456. PMLR, 2015. 2", + "[30] Seijoon Kim, Seongsik Park, Byunggook Na, and Sungroh Yoon. Spiking-yolo: spiking neural network for energy-efficient object detection. In Proceedings of the AAAI conference on artificial intelligence, volume 34, pages 11270-11277, 2020. 1", + "[31] Y. Kim and P. Panda. Revisiting batch normalization for training low-latency deep spiking neural networks from scratch, 2020. 1, 3", + "[32] Alex Krizhevsky, Vinod Nair, and Geoffrey Hinton. Cifar-10 (canadian institute for advanced research). 6", + "[33] Alexander Kugele, Thomas Pfeil, Michael Pfeiffer, and Elisabetta Chicca. Efficient processing of spatio-temporal data streams with spiking neural networks. Frontiers in Neuroscience, 14:439, 05 2020. 8", + "[34] Chankyu Lee, Syed Sarwar, Priyadarshini Panda, Gopalakrishnan Srinivasan, and Kaushik Roy. Enabling spike-based backpropagation for training deep neural network architectures. Frontiers in Neuroscience, 14:119, 02 2020. 6", + "[35] Hongmin Li. Cifar10-dvs: An event-stream dataset for object classification. Frontiers in Neuroscience, 11, 05 2017. 6", + "[36] Hao Li, Zheng Xu, Gavin Taylor, Christoph Studer, and Tom Goldstein. Visualizing the loss landscape of neural nets. Advances in neural information processing systems, 31, 2018. 5", + "[37] Yuhang Li, Shikuang Deng, Xin Dong, and et al. A free lunch from ann: Towards efficient, accurate spiking neural networks calibration. In ICML, 2021. 2", + "[38] Yuhang Li, Yufei Guo, Shanghang Zhang, Shikuang Deng, Yongqing Hai, and Shi Gu. Differentiable spike: Rethinking gradient-descent for training spiking neural networks. Advances in Neural Information Processing Systems, 34, 2021. 2, 4, 6, 7", + "[39] S. A. Lobov and et al. Spatial properties of stdp in a spiking neural network enable controlling a mobile robot. Frontiers in Neuroscience, 2020. 2", + "[40] Ping Luo, Jiamin Ren, Zhanglin Peng, Ruimao Zhang, and Jingyu Li. Differentiable learning-to-normalize via switchable normalization, 2019. 2", + "[41] Mitchell A Nahmias, Bhavin J Shastri, Alexander N Tait, and Paul R Prucnal. A leaky integrate-and-fire laser neuron for ultrafast cognitive computing. IEEE journal of selected topics in quantum electronics, 19(5):1-12, 2013. 3", + "[42] Jing Pei, Lei Deng, Sen Song, Mingguo Zhao, Youhui Zhang, Shuang Wu, Guanrui Wang, Zhe Zou, Zhenzhi Wu, Wei He, Feng Chen, Ning Deng, Si Wu, Yu Wang, Yujie Wu, Zheyu Yang, Cheng Ma, Guoqi Li, Wentao Han, and L.P. Shi. Towards artificial general intelligence with hybrid tianjic chip architecture. Nature, 572:106, 08 2019. 1", + "[43] Peter, U., Diehl, Matthew, and Cook. Unsupervised learning of digit recognition using spike-timing-dependent plasticity. Frontiers in Computational Neuroscience, 9:99, 2015. 2" + ], + "bbox": [ + 78, + 90, + 468, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[44] Nitin Rathi and Kaushik Roy. DIET-SNN: direct input encoding with leakage and threshold optimization in deep spiking neural networks. CoRR, abs/2008.03658, 2020. 5, 6", + "[45] Nitin Rathi, Gopalakrishnan Srinivasan, Priyadarshini Panda, and Kaushik Roy. Enabling deep spiking neural networks with hybrid conversion and spike timing dependent backpropagation. 05 2020. 6, 7", + "[46] Abhronil Sengupta, Yuting Ye, Robert Wang, Chiao Liu, and Kaushik Roy. Going deeper in spiking neural networks: Vgg and residual architectures. Frontiers in Neuroscience, 13, 02 2018. 2, 5, 6, 7", + "[47] Jiangrong Shen, Qi Xu, Jian K Liu, Yueming Wang, Gang Pan, and Huajin Tang. Esl-snns: An evolutionary structure learning strategy for spiking neural networks. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 37, pages 86-93, 2023. 1", + "[48] Dmitry Ulyanov, Andrea Vedaldi, and Victor Lempitsky. Instance normalization: The missing ingredient for fast stylization, 2017. 2", + "[49] Siqi Wang, Tee Hiang Cheng, and Meng-Hiot Lim. LTMD: Learning improvement of spiking neural networks with learnable thresholding neurons and moderate dropout. In Alice H. Oh, Alekh Agarwal, Danielle Belgrave, and Kyunghyun Cho, editors, Advances in Neural Information Processing Systems, 2022. 4", + "[50] Yujie Wu, Lei Deng, and et al. Spatio-temporal backpropagation for training high-performance spiking neural networks. Frontiers in neuroscience, 2018. 2", + "[51] Yujie Wu, Lei Deng, Guoqi Li, Jun Zhu, Yuan Xie, and L.P. Shi. Direct training for spiking neural networks: Faster, larger, better. Proceedings of the AAAI Conference on Artificial Intelligence, 33:1311-1318, 07 2019. 1, 2, 4, 8", + "[52] Yuxin Wu and Kaiming He. Group normalization. In Proceedings of the European conference on computer vision (ECCV), pages 3-19, 2018. 2", + "[53] Zhenzhi Wu, Hehui Zhang, Yihan Lin, Guoqi Li, Meng Wang, and Ye Tang. Liaf-net: Leaky integrate and analog fire network for lightweight and efficient spatiotemporal information processing. IEEE Transactions on Neural Networks and Learning Systems, 33(11):6249-6262, 2022. 8", + "[54] Mingqing Xiao, Qingyan Meng, Zongpeng Zhang, Di He, and Zhouchen Lin. Online training through time for spiking neural networks. arXiv preprint arXiv:2210.04195, 2022. 7", + "[55] Rong Xiao, Yu Wan, Baosong Yang, Haibo Zhang, Huajin Tang, Derek F Wong, and Boxing Chen. Towards energy-preserving natural language understanding with spiking neural networks. IEEE/ACM Transactions on Audio, Speech, and Language Processing, 31:439-447, 2022. 1", + "[56] Qi Xu, Yaxin Li, Xuanye Fang, Jiangrong Shen, Jian K Liu, Huajin Tang, and Gang Pan. Biologically inspired structure learning with reverse knowledge distillation for spiking neural networks. arXiv preprint arXiv:2304.09500, 2023. 1", + "[57] Qi Xu, Yaxin Li, Jiangrong Shen, Jian K Liu, Huajin Tang, and Gang Pan. Constructing deep spiking neural networks from artificial neural networks with knowledge distillation. arXiv preprint arXiv:2304.05627, 2023. 1", + "[58] Qi Xu, Yaxin Li, Jiangrong Shen, Pingping Zhang, Jian K Liu, Huajin Tang, and Gang Pan. Hierarchical spiking-based" + ], + "bbox": [ + 501, + 92, + 890, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "19429", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "model for efficient image classification with enhanced feature extraction and encoding. IEEE Transactions on Neural Networks and Learning Systems, 2022. 1", + "[59] Qi Xu, Jiangrong Shen, Xuming Ran, Huajin Tang, Gang Pan, and Jian K Liu. Robust transcoding sensory information with neural spikes. IEEE Transactions on Neural Networks and Learning Systems, 33(5):1935-1946, 2021. 1", + "[60] Xingting Yao, Fanrong Li, Zitao Mo, and Jian Cheng. Glif: A unified gated leaky integrate-and-fire neuron for spiking neural networks. arXiv preprint arXiv:2210.13768, 2022. 6, 7", + "[61] Wenrui Zhang and Peng Li. Temporal spike sequence learning via backpropagation for deep spiking neural networks. 02 2020. 7", + "[62] Hanle Zheng, Yujie Wu, Lei Deng, Yifan Hu, and Guoqi Li. Going deeper with directly-trained larger spiking neural networks. 10 2020. 1, 3, 6, 7, 8" + ], + "bbox": [ + 78, + 90, + 468, + 330 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "19430", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/cc22facf-9790-4a7c-8861-ea4adecda7ac_model.json b/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/cc22facf-9790-4a7c-8861-ea4adecda7ac_model.json new file mode 100644 index 0000000000000000000000000000000000000000..86fc58dd2151f5aef8dc876f9b9aa607f949f4b2 --- /dev/null +++ b/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/cc22facf-9790-4a7c-8861-ea4adecda7ac_model.json @@ -0,0 +1,2532 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.125, + 0.131, + 0.847, + 0.154 + ], + "angle": 0, + "content": "Membrane Potential Batch Normalization for Spiking Neural Networks" + }, + { + "type": "text", + "bbox": [ + 0.136, + 0.181, + 0.835, + 0.253 + ], + "angle": 0, + "content": "Yufei Guo,\\* Yuhan Zhang,\\* Yuanpei Chen, Weihang Peng, Xiaode Liu, Liwen Zhang, Xuhui Huang, Zhe Ma\\* Intelligent Science & Technology Academy of CASIC, China Scientific Research Laboratory of Aerospace Intelligent Systems and Technology, China" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.287, + 0.314, + 0.303 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.32, + 0.473, + 0.668 + ], + "angle": 0, + "content": "As one of the energy-efficient alternatives of conventional neural networks (CNNs), spiking neural networks (SNNs) have gained more and more interest recently. To train the deep models, some effective batch normalization (BN) techniques are proposed in SNNs. All these BNs are suggested to be used after the convolution layer as usually doing in CNNs. However, the spiking neuron is much more complex with the spatio-temporal dynamics. The regulated data flow after the BN layer will be disturbed again by the membrane potential updating operation before the firing function, i.e., the nonlinear activation. Therefore, we advocate adding another BN layer before the firing function to normalize the membrane potential again, called MPBN. To eliminate the induced time cost of MPBN, we also propose a training-inference-decoupled re-parameterization technique to fold the trained MPBN into the firing threshold. With the re-parameterization technique, the MPBN will not introduce any extra time burden in the inference. Furthermore, the MPBN can also adopt the element-wised form, while these BNs after the convolution layer can only use the channel-wised form. Experimental results show that the proposed MPBN performs well on both popular non-spiking static and neuromorphic datasets." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.699, + 0.21, + 0.715 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.726, + 0.47, + 0.862 + ], + "angle": 0, + "content": "Emerged as a biology-inspired method, spiking neural networks (SNNs) have received much attention in artificial intelligence and neuroscience recently [17, 13, 57, 56, 47, 58, 59]. SNNs deal with binary event-driven spikes as their activations and therefore the multiplications of activations and weights can be substituted for additions or only keeping silent. Benefitting from such a computation paradigm, SNNs derive extreme energy efficiency and run efficiently when implemented on neuromorphic hardware [1, 42, 5]." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.288, + 0.895, + 0.712 + ], + "angle": 0, + "content": "Despite the SNN has achieved great success in diverse fields including pattern recognition [12, 21, 19, 14], object detection [30], language processing [55], robotics [9], and so on, its development is deeply inspired by the experience of convolutional neural networks (CNNs) in many aspects. However, the spiking neuron model along with the rich spatio-temporal dynamic makes SNNs much different from CNNs, and directly transferring some experience of CNNs to SNNs without any modifications may be not a good idea. As one of the famous techniques in CNNs, the batch normalization(BN) technique shows great advantages. It can reduce the gradient exploding/vanishing problem, flatten the loss landscape, and reduce the internal covariate shift, thus being widely used in CNNs. There are also some works trying to apply normalization approaches in the SNN field to help model convergence. For example, inspired by BN in CNNs, NeuNorm [51] was proposed to normalize the data along the channel dimension. Considering that the temporal dimension is also important in SNNs, threshold-dependent batch normalization (tdBN) [62] then extended the scope of BN to the additional temporal dimension. Subsequently, to better depict the differences of data flow distributions in different time dimensions, the temporal batch normalization through time (BNTT) [31], postsynaptic potential normalization (PSP-BN) [28], and temporal effective batch normalization (TEBN) [10] that regulate the data flows with multiple BNs on different time steps were proposed." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.895, + 0.903 + ], + "angle": 0, + "content": "However, all these BNs proposed in SNNs are advised to be used after convolution layers as usually doing in CNNs. This ignores the fact that the nonlinear transformation in the SNN spiking neuron is much more complex than that of the ReLU neuron. In the spiking neuron, the data flow after the convolution layer will be first injected into the residual membrane potential (MP) coming from the previous time step to generate a new MP at the current time step. And then the neuron will fire a spike or keep silent still based on whether or not the new MP is up to the firing threshold. Obviously, though the data flow has been normalized by the BN after the convolution layer, it will be" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.875, + 0.342, + 0.901 + ], + "angle": 0, + "content": "*Equal contribution. \n†Corresponding author, mazhe_thu@163.com." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "19420" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.113, + 0.09, + 0.437, + 0.297 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.308, + 0.473, + 0.399 + ], + "angle": 0, + "content": "Figure 1: The difference between our SNN with MPBN and the vanilla SNN. We add another BN layer after membrane potential updating (MPU) operation in the training. The MPBN can be folded into the firing threshold and then the homogenous firing threshold will be transformed into different ones." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.422, + 0.472, + 0.633 + ], + "angle": 0, + "content": "disturbed again by the residual MP in the membrane potential updating process. Therefore, we advocate also adding a BN layer after MP updating to regulate the data flow once again, called MPBN. Furthermore, we also propose a training-inference-decoupled re-parameterization technique in SNNs to fold the trained MPBN into the firing threshold. Hence, the MPBN will not induce any extra burden in the inference but a trivial burden in the training. The MPBN can be extended to channel-wised MPBN and element-wised MPBN further, which is very different from that of CNNs where only channel-wised normalization can be folded into weights. The difference between our SNN with MPBN and the vanilla SNN is illustrated in Fig. 1. Our main contributions are as follows:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.643, + 0.47, + 0.735 + ], + "angle": 0, + "content": "- We propose to add another BN layer after the membrane potential updating operation named MPBN to handle the data flow disturbance in the spiking neuron. The experiment shows that MPBN can flatten the loss landscape further, thus benefiting model convergence and task accuracy." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.741, + 0.47, + 0.864 + ], + "angle": 0, + "content": "- We also propose a re-parameterization method to decouple the training-time SNN and the inference-time SNN. In specific, we propose a method to fold the trained MPBN parameter into the firing threshold. Therefore, MPBN can be seen as only training auxiliary manner free from burdens in the inference-time. This re-parameterization method is suitable for both channel-wised MPBN and element-wised MPBN." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.871, + 0.472, + 0.902 + ], + "angle": 0, + "content": "- Extensive experiment results show that the SNN trained with the MPBN is highly effective compared" + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.643, + 0.472, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.532, + 0.092, + 0.894, + 0.153 + ], + "angle": 0, + "content": "with other state-of-the-art SNN models on both static and dynamic datasets, e.g., \\(96.47\\%\\) top-1 accuracy and \\(79.51\\%\\) top-1 accuracy are achieved on the CIFAR-10 and CIFAR-100 with only 2 time steps." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.168, + 0.642, + 0.184 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.193, + 0.826, + 0.21 + ], + "angle": 0, + "content": "2.1. Learning of Spiking Neural Networks" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.217, + 0.895, + 0.596 + ], + "angle": 0, + "content": "There are three kinds of learning algorithms of SNNs, including unsupervised learning [43, 24], converting ANN to SNN (ANN2SNN) [46, 25, 26], and supervised learning [19, 38, 20]. Unsupervised learning adopts some biological mechanism to update the SNN model, i.e., the spiketiming-dependent plasticity (STDP) approach [39], thus being considered a biologically plausible method. However, STDP cannot help train large-scale networks yet, thus it is usually limited to small datasets and non-ideal performance. The ANN-SNN conversion approach [22, 37] obtains an SNN by reusing well-trained homogeneous ANN parameters and replacing the ReLU neuron with a spiking neuron. Since the ANN model is easier to train and reach high performance, the ANN-SNN conversion method provides an interesting way to generate an SNN in a short time with competitive performance. However, the converted SNN will lose the rich temporal dynamic behaviors and thus cannot handle neuromorphic datasets well. Supervised learning [11, 50, 18] adopts the surrogate gradient (SG) approach to train SNNs with error backpropagation. It can handle temporal data and provide decent performance with few time steps on the large-scale dataset, thus having received much attention recently. For a more detailed introduction, please refer to the recent SNN survey [17]. Our work falls under the supervised learning." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.605, + 0.866, + 0.621 + ], + "angle": 0, + "content": "2.2. Normalization in Spiking Neural Networks" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.629, + 0.892, + 0.854 + ], + "angle": 0, + "content": "The batch normalization technique was originally introduced as a kind of training auxiliary method by [29] in CNNs. It uses the weight-summed input over a mini-batch of training cases to compute a mean and variance and then uses them to regulate the summed input. This simple operation can derive many benefits. i) It reduces the internal covariate shift (ICS), thus accelerating the training of a deep neural network. ii) It makes the network insensitive to the scale of the gradients, thus a higher learning rate can be chosen to accelerate the training. iii) It makes the network suitable for more nonlinearities by preventing the network from getting stuck in the saturated modes. With these advantages, more kinds of BNs were proposed, including layer normalization [2], group normalization [52], instance normalization [48], and switchable normalization [40]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.894, + 0.901 + ], + "angle": 0, + "content": "There are also some works that modify and apply normalization approaches in the SNN field. For example, NeuNorm [51] also normalizes the feature map along the chan" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "19421" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.438 + ], + "angle": 0, + "content": "nel dimension like BN in CNNs. Recently, some methods were proposed to normalize the feature map from both the channel dimension and temporal dimension to take care of the spatio-temporal characteristics of the SNN, such as the threshold-dependent batch normalization (tdBN) [62]. It extends the scope of BN to the additional temporal dimension by adopting a 3DBN-like normalization method in CNNs. Note that, the tdBN can be folded into the weights, thus inducing no burden in the inference time. Nevertheless, NeuNorm and tdBN still use the shared parameters along the temporal dimension. Some works argued that the distributions of data in different time steps vary wildly and that using shared parameters is not a good choice. Subsequently, the temporal batch normalization through time (BNTT) [31], postsynaptic potential normalization (PSP-BN) [28], and temporal effective batch normalization (TEBN) [10] were proposed. These BNs regulate the data flow utilizing different parameters through time steps. Though these BNs with different BN parameters on different time steps can train more well-performed SNN models, their parameters can not be folded into the weights, thus will increase the computations and running time in the inference." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.44, + 0.473, + 0.577 + ], + "angle": 0, + "content": "Nevertheless, all these BNs in the SNN field are advised to be used after convolution layers. However, the data flow after the convolution layer will not be presented to the firing function directly but to the membrane potential updating function first. Hence, the data flow will be disturbed again before reaching the firing function. To this end, in this paper, we add another BN after the membrane potential updating function, called the MPBN to retain normalized data flow before the firing function." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.593, + 0.205, + 0.61 + ], + "angle": 0, + "content": "3. Preliminary" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.619, + 0.364, + 0.635 + ], + "angle": 0, + "content": "3.1. Leaky Integrate-and-Fire Model" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.643, + 0.47, + 0.794 + ], + "angle": 0, + "content": "Different from CNNs, SNNs use binary spikes to transmit information. In the paper, we use the widely used Leaky-Integrate-and-Fire (LIF) neuron model [41] to introduce the unique spatial-temporal dynamic of the spiking model. First, we introduce the notation rules used here as follows. Vectors or tensors are denoted by bold italic letters, i.e., \\( \\mathbf{x} \\) and \\( \\mathbf{o} \\) represent the input and output variables respectively. Matrices are denoted by bold capital letters. For instance, \\( \\mathbf{W} \\) is the weight matrix. The constant is denoted by small letters." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.796, + 0.397, + 0.811 + ], + "angle": 0, + "content": "In LIF, the membrane potential is updated by" + }, + { + "type": "equation", + "bbox": [ + 0.09, + 0.822, + 0.47, + 0.855 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {u} ^ {(t + 1), \\text {p r e}} = \\tau \\boldsymbol {u} ^ {(t)} + \\boldsymbol {c} ^ {(t + 1)}, \\text {w h e r e} \\boldsymbol {c} ^ {(t + 1)} = \\mathbf {W} \\boldsymbol {x} ^ {(t + 1)}, \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.47, + 0.902 + ], + "angle": 0, + "content": "where \\(\\pmb{u}\\) represents the membrane potential and \\(\\pmb{u}^{(t + 1),\\mathrm{pre}}\\) is the updated membrane potential at time step \\(t + 1\\), \\(\\pmb{c}^{(t + 1)}\\) is the pre-synaptic input at time step \\(t + 1\\), which is charged" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.091, + 0.892, + 0.168 + ], + "angle": 0, + "content": "by weight-summed input spikes \\( \\pmb{x}^{(t + 1)} \\), and \\( \\tau \\) is a constant within (0, 1), which controls the leakage of the membrane potential. Then, when the updated membrane potential \\( \\pmb{u}^{(t + 1),\\mathrm{pre}} \\) is up to the firing threshold \\( V_{\\mathrm{th}} \\), the LIF spiking neuron will fire a spike as below," + }, + { + "type": "equation", + "bbox": [ + 0.577, + 0.18, + 0.892, + 0.22 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {o} ^ {(t + 1)} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f} \\boldsymbol {u} ^ {(t + 1), \\text {p r e}} > V _ {\\text {t h}} \\\\ 0 & \\text {o t h e r w i s e} \\end{array} , \\right. \\tag {2}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.582, + 0.223, + 0.815, + 0.242 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {u} ^ {(t + 1)} = \\boldsymbol {u} ^ {(t + 1), \\text {p r e}} \\cdot (1 - \\boldsymbol {o} ^ {(t + 1)}).\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.256, + 0.892, + 0.332 + ], + "angle": 0, + "content": "After firing, the spike output \\( \\pmb{o}^{(t + 1)} \\) at time step \\( t + 1 \\) will be transmitted to the next layer and become its input. At the same time, the updated membrane potential will be reset to zero and becomes \\( \\pmb{u}^{(t + 1)} \\) to join the neuron processing at the next time step." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.334, + 0.892, + 0.454 + ], + "angle": 0, + "content": "The Classifier in the SNN. In a classification model, the final output is used to compute the Softmax and predict the desired class object. In an SNN model, if we also use LIF neurons at the output layer to fire spikes and use the number of spikes to compute the probability, too much information will be lost. Therefore, we only integrate the output and do not fire them across time, as doing in recent work [20, 21, 12]." + }, + { + "type": "equation", + "bbox": [ + 0.577, + 0.456, + 0.892, + 0.497 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {o} _ {\\text {o u t}} = \\frac {1}{T} \\sum_ {t = 1} ^ {T} \\boldsymbol {c} _ {\\text {o u t}} ^ {(t)} = \\frac {1}{T} \\sum_ {t = 1} ^ {T} \\mathbf {W} \\boldsymbol {x} ^ {(t)}. \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.505, + 0.892, + 0.536 + ], + "angle": 0, + "content": "Then, the cross-entropy loss is computed based on the true label and \\(\\operatorname{Softmax}(\\pmb{o}_{\\mathrm{out}})\\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.548, + 0.766, + 0.563 + ], + "angle": 0, + "content": "3.2. Batch Normalization in SNNs" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.572, + 0.892, + 0.679 + ], + "angle": 0, + "content": "Batch normalization can effectively reduce the internal covariate shift and alleviate the gradient vanishing or explosion problem for training networks, thus having been widely used in CNNs. Fortunately, BN can also be used in SNNs. Considering a spiking neuron with input \\( \\pmb{c} = \\{c^{(1)}, c^{(2)}, \\dots, c^{(t)}, \\dots\\} \\), where \\( t \\) is the time step, BN regulate the input at each time step as follows," + }, + { + "type": "equation", + "bbox": [ + 0.635, + 0.691, + 0.892, + 0.731 + ], + "angle": 0, + "content": "\\[\n\\tilde {\\boldsymbol {c}} _ {i} ^ {(t)} = \\frac {\\boldsymbol {c} _ {i} ^ {(t)} - \\boldsymbol {\\mu} _ {i}}{\\sqrt {\\boldsymbol {\\sigma} _ {i} ^ {2} + \\epsilon}}, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.744, + 0.892, + 0.84 + ], + "angle": 0, + "content": "where \\( c_{i}^{(t)} \\) is the input in \\( i \\)-th channel at \\( t \\)-th time step, \\( \\mu_{i} \\) and \\( \\sigma_{i} \\) are the mean and variance of input in channel dimension, and \\( \\epsilon \\) is a small constant to avoid denominator being zero. To ensure BN can represent the identity transformation, the normalized vector \\( \\tilde{c}_{i}^{(t)} \\) is scaled and shifted in a learning manner as follows," + }, + { + "type": "equation", + "bbox": [ + 0.612, + 0.852, + 0.892, + 0.873 + ], + "angle": 0, + "content": "\\[\n\\operatorname {B N} \\left(\\boldsymbol {c} _ {i} ^ {(t)}\\right) = \\boldsymbol {\\lambda} _ {i} \\tilde {\\boldsymbol {c}} _ {i} ^ {(t)} + \\boldsymbol {\\beta} _ {i}, \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.886, + 0.878, + 0.902 + ], + "angle": 0, + "content": "where \\(\\lambda_{i}\\) and \\(\\beta_{i}\\) are channel-wised learnable parameters." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19422" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.09, + 0.212, + 0.108 + ], + "angle": 0, + "content": "4. Methodology" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.115, + 0.473, + 0.252 + ], + "angle": 0, + "content": "This section first introduces the specific form of membrane potential batch normalization. Then the reparameterization technique that how to fold the MPBN into \\( V_{\\mathrm{th}} \\) will be introduced in detail. Next, some key details for training the SNN and the pseudocode for the training and inference of our SNN will be given. Finally, we will provide plenty of ablation studies and the comparison of the loss landscape of the models with or without MPBN to show the effectiveness of the proposed method." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.26, + 0.437, + 0.275 + ], + "angle": 0, + "content": "4.1. Membrane Potential Batch Normalization" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.283, + 0.47, + 0.358 + ], + "angle": 0, + "content": "As abovementioned, we argue that though the data flow has been normalized by the BN after the convolution layer, it will be disturbed again by the membrane potential updating operation. To better depict this, we give the vanilla form of LIF neuron with BN first as follows," + }, + { + "type": "equation", + "bbox": [ + 0.149, + 0.365, + 0.47, + 0.384 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {u} ^ {(t + 1), \\text {p r e}} = \\tau \\boldsymbol {u} ^ {(t)} + \\mathrm {B N} (\\mathbf {W} \\boldsymbol {x} ^ {(t + 1)}), \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.393, + 0.47, + 0.466 + ], + "angle": 0, + "content": "where \\(\\tau\\) is 0.25 in the paper following [21, 38, 4]. To regulate the disturbed data flow once again, We further embed another BN after the membrane potential updating operation, called MPBN. The LIF neuron with MPBN can be updated as" + }, + { + "type": "equation", + "bbox": [ + 0.165, + 0.466, + 0.469, + 0.485 + ], + "angle": 0, + "content": "\\[\n\\tilde {\\boldsymbol {u}} ^ {(t + 1), \\text {p r e}} = \\operatorname {M P B N} (\\boldsymbol {u} ^ {(t + 1), \\text {p r e}}). \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.488, + 0.47, + 0.595 + ], + "angle": 0, + "content": "Obviously, \\(\\pmb{u}^{(t + 1),\\mathrm{pre}}\\) will be scaled and sifted, and some \\(\\pmb{u}^{(t + 1),\\mathrm{pre}}\\) less than \\(V_{\\mathrm{th}}\\) may be greater than \\(V_{\\mathrm{th}}\\) with MPBN and vice versa. This is abhorrent with the biology and MPBN will cause some extra computation burden in the inference compared with the vanilla one. To solve this problem, we also propose a training-inference-decoupled re-parameterization technique here." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.603, + 0.274, + 0.618 + ], + "angle": 0, + "content": "4.2. Re-parameterization" + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.626, + 0.433, + 0.642 + ], + "angle": 0, + "content": "With MPBN, the firing function will be updated as" + }, + { + "type": "equation", + "bbox": [ + 0.124, + 0.648, + 0.469, + 0.69 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {o} ^ {(t + 1)} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f M P B N} (\\boldsymbol {u} ^ {(t + 1), \\text {p r e}}) > V _ {\\text {t h}} \\\\ 0 & \\text {o t h e r w i s e} \\end{array} . \\right. \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.696, + 0.469, + 0.726 + ], + "angle": 0, + "content": "If we unfold the MPBN, the above equation will be reorganized as" + }, + { + "type": "equation", + "bbox": [ + 0.119, + 0.734, + 0.469, + 0.782 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {o} _ {i} ^ {(t + 1)} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f} \\lambda_ {i} \\frac {\\boldsymbol {u} _ {i} ^ {(t + 1) , \\text {p r e}} - \\boldsymbol {\\mu} _ {i}}{\\sqrt {\\sigma_ {i} ^ {2}}} + \\beta_ {i} > V _ {\\text {t h}} \\\\ 0 & \\text {o t h e r w i s e} \\end{array} . \\right. \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.79, + 0.469, + 0.82 + ], + "angle": 0, + "content": "By folding the MPBN to \\( V_{\\mathrm{th}} \\), the firing function will be further updated as" + }, + { + "type": "equation", + "bbox": [ + 0.149, + 0.828, + 0.469, + 0.873 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {o} _ {i} ^ {(t + 1)} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f} \\boldsymbol {u} ^ {(t + 1), \\text {p r e}} > \\left(\\tilde {\\boldsymbol {V}} _ {\\mathrm {t h}}\\right) _ {i} \\\\ 0 & \\text {o t h e r w i s e} \\end{array} , \\right. \\tag {10}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.142, + 0.873, + 0.405, + 0.905 + ], + "angle": 0, + "content": "where \\((\\tilde{V}_{\\mathrm{th}})_i = \\frac{(V_{\\mathrm{th}} - \\beta_i)\\sqrt{\\sigma_i^2}}{\\lambda_i} +\\pmb {\\mu}_i\\)" + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.091, + 0.826, + 0.106 + ], + "angle": 0, + "content": "Algorithm 1 Training and inference of our SNN." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.109, + 0.567, + 0.123 + ], + "angle": 0, + "content": "Training" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.124, + 0.892, + 0.153 + ], + "angle": 0, + "content": "Input: An SNN to be trained with MPBN; training dataset; total training iteration: \\( I_{\\text{train}} \\)." + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.154, + 0.713, + 0.168 + ], + "angle": 0, + "content": "Output: The well-trained SNN." + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.171, + 0.78, + 0.186 + ], + "angle": 0, + "content": "1: for all \\( i = 1,2,\\ldots ,{I}_{\\text{train }} \\) iteration do" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.187, + 0.891, + 0.216 + ], + "angle": 0, + "content": "2: Get mini-batch training data, \\( \\pmb{x}_{\\mathrm{in}}(i) \\) and class label, \\( \\pmb{y}(i) \\);" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.217, + 0.891, + 0.246 + ], + "angle": 0, + "content": "3: Feed the \\( \\pmb{x}_{\\mathrm{in}}(i) \\) into the SNN and regulate the data flow by BN and MPBN;" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.247, + 0.84, + 0.262 + ], + "angle": 0, + "content": "4: Calculate the SNN output, \\( \\pmb{o}_{\\mathrm{out}}(i) \\) by Eq. 3;" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.263, + 0.892, + 0.292 + ], + "angle": 0, + "content": "5: Compute classification loss \\(L_{\\mathrm{CE}}\\) = \\(\\mathcal{L}_{\\mathrm{CE}}(\\pmb{o}_{\\mathrm{out}}(i),\\pmb{y}(i));\\)" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.293, + 0.825, + 0.307 + ], + "angle": 0, + "content": "6: Calculate the gradient w.r.t. W by Eq. 11;" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.308, + 0.891, + 0.336 + ], + "angle": 0, + "content": "7: Update \\(\\mathbf{W}\\): \\((\\mathbf{W} \\leftarrow \\mathbf{W} - \\eta \\frac{\\partial L}{\\partial \\mathbf{W}})\\) where \\(\\eta\\) is learning rate." + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.338, + 0.584, + 0.35 + ], + "angle": 0, + "content": "8: end for" + }, + { + "type": "list", + "bbox": [ + 0.511, + 0.171, + 0.892, + 0.35 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.355, + 0.65, + 0.369 + ], + "angle": 0, + "content": "Re-parameterization" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.37, + 0.892, + 0.398 + ], + "angle": 0, + "content": "Input: The trained SNN with MPBN; total number of MPBN: \\( n \\)." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.4, + 0.891, + 0.43 + ], + "angle": 0, + "content": "Output: The re-parameterized trained SNN without MPBN but diverse \\( V_{\\mathrm{th}} \\)." + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.433, + 0.75, + 0.447 + ], + "angle": 0, + "content": "1: for all \\( i = 1,2,\\ldots ,n \\) number do" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.448, + 0.891, + 0.477 + ], + "angle": 0, + "content": "2: Fold the parameters of \\(i\\)-th MPBN into \\(i\\)-th \\(V_{\\mathrm{th}}\\) by Eq. 10;" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.48, + 0.584, + 0.491 + ], + "angle": 0, + "content": "3: end for" + }, + { + "type": "list", + "bbox": [ + 0.511, + 0.433, + 0.891, + 0.491 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.496, + 0.572, + 0.508 + ], + "angle": 0, + "content": "Inference" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.511, + 0.891, + 0.541 + ], + "angle": 0, + "content": "Input: The re-parameterized trained SNN; test dataset; total test iteration: \\( I_{\\mathrm{test}} \\)." + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.542, + 0.64, + 0.556 + ], + "angle": 0, + "content": "Output: The output." + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.559, + 0.774, + 0.573 + ], + "angle": 0, + "content": "1: for all \\( i = 1,2,\\ldots ,{I}_{\\text{test }} \\) iteration do" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.574, + 0.89, + 0.603 + ], + "angle": 0, + "content": "2: Get mini-batch test data, \\( \\mathbf{x}_{\\mathrm{in}}(i) \\) and class label, \\( \\mathbf{y}(i) \\) in test dataset;" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.604, + 0.89, + 0.633 + ], + "angle": 0, + "content": "3: Feed the \\( \\pmb{x}_{\\mathrm{in}}(i) \\) into the reparameterized SNN without MPBN;" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.635, + 0.84, + 0.65 + ], + "angle": 0, + "content": "4: Calculate the SNN output, \\( \\pmb{o}_{\\mathrm{out}}(i) \\) by Eq. 3;" + }, + { + "type": "text", + "bbox": [ + 0.511, + 0.65, + 0.89, + 0.678 + ], + "angle": 0, + "content": "5: Compare the classification factor \\( \\pmb{o}_{\\mathrm{out}}(i) \\) and \\( \\pmb{y}(i) \\) for classification." + }, + { + "type": "list", + "bbox": [ + 0.511, + 0.559, + 0.89, + 0.678 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.511, + 0.68, + 0.583, + 0.692 + ], + "angle": 0, + "content": "6: end for" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.726, + 0.892, + 0.832 + ], + "angle": 0, + "content": "It can be seen that by absorbing some parameters from MPBN, \\( V_{\\mathrm{th}} \\) will be transformed to another channel-wised \\( (\\tilde{V}_{\\mathrm{th}})_i \\). In this way, the extra computation burden caused by MPBN will be eliminated again in the inference time. Furthermore, the diversity of the spiking neuron will be improved with abundant firing parameters as the learnable firing threshold in other work [3, 49]." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.846, + 0.698, + 0.862 + ], + "angle": 0, + "content": "4.3. Training Framework" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "In the paper, the spatial-temporal backpropagation (STBP) algorithm [51] is adopted to train the SNN mod" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19423" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.088, + 0.095, + 0.257, + 0.198 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.137, + 0.205, + 0.221, + 0.217 + ], + "angle": 0, + "content": "(a) CIFAR-10" + }, + { + "type": "image", + "bbox": [ + 0.28, + 0.096, + 0.445, + 0.198 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.324, + 0.205, + 0.415, + 0.217 + ], + "angle": 0, + "content": "(b) CIFAR-100" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.23, + 0.47, + 0.292 + ], + "angle": 0, + "content": "Figure 2: The accuracy curves of spiking ResNet20 with or without MPBN using 2 time steps on CIFAR-10 (left) and CIFAR-100 (right). The MPBN based SNNs obviously enjoy higher accuracy and easier convergence." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.319, + 0.469, + 0.41 + ], + "angle": 0, + "content": "els. STBP treats the SNN model as a self-recurrent neural network thus enabling an error backpropagation mechanism following the same principles as in CNNs. However, there is still a problem impeding the direct training of SNNs. To demonstrate this problem, we formulate the gradient at the layer \\(l\\) by the chain rule, given by" + }, + { + "type": "equation", + "bbox": [ + 0.078, + 0.422, + 0.47, + 0.472 + ], + "angle": 0, + "content": "\\[\n\\frac {\\partial L}{\\partial \\mathbf {W} ^ {l}} = \\sum_ {t} \\left(\\frac {\\partial L}{\\partial \\boldsymbol {o} ^ {(t) , l}} \\frac {\\partial \\boldsymbol {o} ^ {(t) , l}}{\\partial \\boldsymbol {u} ^ {(t) , l}} + \\frac {\\partial L}{\\partial \\boldsymbol {u} ^ {(t + 1) , l}} \\frac {\\partial \\boldsymbol {u} ^ {(t + 1) , l}}{\\partial \\boldsymbol {u} ^ {(t) , l}}\\right) \\frac {\\partial \\boldsymbol {u} ^ {(t) , l}}{\\partial \\mathbf {W} ^ {l}}, \\tag {11}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.473, + 0.469, + 0.611 + ], + "angle": 0, + "content": "where \\(\\frac{\\partial\\pmb{o}^{(t),l}}{\\partial\\pmb{u}^{(t),l}}\\) is the gradient of firing function at at \\(t\\)-th time step in \\(l\\)-th layer. Obviously, the non-differentiable firing activity of the spiking neuron will result in zero gradients everywhere, while infinity at \\(V_{\\mathrm{th}}\\). Therefore, the gradient descent \\((\\mathbf{W}^l\\gets \\mathbf{W}^l -\\eta \\frac{\\partial L}{\\partial\\mathbf{W}^l})\\) either freezes or updates to infinity in the backpropagation. To handle this problem, here, we also adopt the commonly used STE surrogate gradients as doing in other surrogate gradients (SG) methods [44, 20]. Mathematically, it is defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.158, + 0.624, + 0.469, + 0.657 + ], + "angle": 0, + "content": "\\[\n\\frac {d \\boldsymbol {o}}{d \\boldsymbol {u}} = \\left\\{ \\begin{array}{l l} 1, & \\text {i f} 0 \\leq \\boldsymbol {u} \\leq 1 \\\\ 0, & \\text {o t h e r w i s e} \\end{array} \\right.. \\tag {12}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.668, + 0.469, + 0.699 + ], + "angle": 0, + "content": "Then, the SNN model can be trained end-to-end. The training and inference of our SNN are detailed in Algo. 1." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.711, + 0.23, + 0.727 + ], + "angle": 0, + "content": "4.4. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.469, + 0.901 + ], + "angle": 0, + "content": "To verify the effectiveness of the MPBN, a lot of ablative studies using spiking ResNet20 architecture along with different time steps were conducted on the CIFAR-10 and CIFAR-100 datasets. The results of top-1 accuracy of these models are shown in Tab. 1. It's can be seen that the test accuracy of the SNNs with MPBN is always higher than these vanilla counterparts. For example, the accuracy of baseline SNN with 1 time step is \\(90.40\\%\\), while with MPBN, it will increase up to \\(92.22\\%\\), which is a huge improvement (more than \\(2.0\\%\\)) in the SNN field. Moreover, we also show the test accuracy curves of ResNet20 using MPBN and its" + }, + { + "type": "table_caption", + "bbox": [ + 0.556, + 0.09, + 0.836, + 0.105 + ], + "angle": 0, + "content": "Table 1: Ablation experiments for MPBN." + }, + { + "type": "table", + "bbox": [ + 0.521, + 0.116, + 0.875, + 0.327 + ], + "angle": 0, + "content": "
DatasetMethodTime stepAccuracy
CIFAR-10baseline190.40%
w/ MPBN192.22%
baseline292.80%
w/ MPBN293.54%
baseline493.85%
w/ MPBN494.28%
CIFAR-100baseline167.94%
w/ MPBN168.36%
baseline270.18%
w/ MPBN270.79%
baseline471.77%
w/ MPBN472.30%
" + }, + { + "type": "image", + "bbox": [ + 0.511, + 0.341, + 0.693, + 0.435 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.57, + 0.443, + 0.634, + 0.456 + ], + "angle": 0, + "content": "(a) MPBN" + }, + { + "type": "image", + "bbox": [ + 0.703, + 0.341, + 0.884, + 0.435 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.76, + 0.443, + 0.825, + 0.456 + ], + "angle": 0, + "content": "(b) Vanilla" + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.469, + 0.892, + 0.499 + ], + "angle": 0, + "content": "Figure 3: The 1D loss landscape of spiking ResNet20 with and without MPBN." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.527, + 0.892, + 0.618 + ], + "angle": 0, + "content": "vanilla counterpart with 2 time steps on CIFAR-10/100 during training in Fig. 2. It can be observed obviously that the SNNs with MPBN also perform better on convergence speed. To sum up, the proposed MPBN can both improve accuracy and convergence speed, which are very important aspects in deep learning." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.627, + 0.66, + 0.644 + ], + "angle": 0, + "content": "4.5. Loss Landscape" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.65, + 0.892, + 0.816 + ], + "angle": 0, + "content": "We further inspect the 1D loss landscapes [36] of the SNNs with or without MPBN using spiking ResNet20 architecture in 2 time steps to show why the MPBN can improve accuracy and convergence speed in Fig. 3. It can be observed that the loss landscape of the SNN model with MPBN is flatter than that of the SNN without MPBN. This indicates that the MPBN makes the landscape of the corresponding optimization problem smoother [36], thus making the gradients more predictive and network faster convergence. The results here provide convincing evidence for ablation studies in Section 4.4." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.831, + 0.633, + 0.848 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.902 + ], + "angle": 0, + "content": "In this section, abundant experiments were conducted to verify the effectiveness of the MPBN using widely-used spiking ResNet20 [44, 46], VGG16 [44], ResNet18 [11]," + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19424" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.299, + 0.089, + 0.672, + 0.105 + ], + "angle": 0, + "content": "Table 2: Comparison with SoTA methods on CIFAR-10." + }, + { + "type": "table", + "bbox": [ + 0.158, + 0.116, + 0.817, + 0.661 + ], + "angle": 0, + "content": "
DatasetMethodTypeArchitectureTimestepAccuracy
CIFAR-10SpikeNorm [46]ANN2SNNVGG16250091.55%
Hybrid-Train [45]Hybrid trainingVGG1620092.02%
Spike-basedBP [34]SNN trainingResNet1110090.95%
Joint A-SNN [19]SNN trainingResNet18495.45%
GLIF [60]SNN trainingResNet19294.44%
PLIF [12]SNN trainingPLIFNet893.50%
Diet-SNN [44]SNN trainingVGG16592.70%
1093.44%
ResNet20591.78%
1092.54%
RecDis-SNN [20]SNN trainingResNet19293.64%
495.53%
695.55%
Dspike [38]SNN trainingResNet20293.13%
493.66%
694.25%
STBP-tdBN [62]SNN trainingResNet19292.34%
492.92%
693.16%
TET [7]SNN trainingResNet19294.16%
494.44%
694.50%
Real Spike [21]SNN trainingResNet19295.31%
495.51%
696.10%
InfLoR-SNN [16]SNN trainingResNet20593.01%
1093.65%
MPBNSNN trainingResNet19196.06%±0.10
296.47%±0.08
ResNet20192.22%±0.11
293.54%±0.09
494.28%±0.07
VGG16293.96%±0.09
494.44%±0.08
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.685, + 0.473, + 0.898 + ], + "angle": 0, + "content": "ResNet19 [62], and ResNet34 [11] on both static datasets including CIFAR-10 [32], CIFAR-100 [32], and ImageNet [6], and one neuromorphic dataset, CIFAR10-DVS [35]. The specific introduction for these datasets has been detailed in many recent works [62, 44, 21, 38]. Here, we mainly introduce these hyper-parameters and data preprocessing in detail. We used the widely adopted LIF neuron in our SNN models as other works about direct training methods [44, 46]. These hyper-parameters for LIF neuron about the initial firing threshold \\( V_{\\mathrm{th}} \\) and the membrane potential decaying constant \\( \\tau_{\\mathrm{decay}} \\) are 0.5 and 0.25 respectively. For static image datasets, since encoding the 8-bit RGB images into 1-bit spikes will lose too much information, we use an ANN-like convolutional layer and a LIF layer to encode the" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.685, + 0.892, + 0.715 + ], + "angle": 0, + "content": "images to spikes for all the rest of the layers, as in recent works [62, 44, 21, 38]." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.726, + 0.79, + 0.743 + ], + "angle": 0, + "content": "5.1. Comparison with SoTA Methods" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.895, + 0.903 + ], + "angle": 0, + "content": "CIFAR-10. On CIFAR-10, we trained our SNN model using the SGD optimizer with 0.9 momentum. The initial learning rate is 0.1 and decays to 0 in cosine form. The total training time is 400 epochs. To fairly compare with these recent SoTA methods [38, 20, 16], we also adopt data normalization, random horizontal flipping, cropping, and cutout [8] for data augmentation. We run three times for each experiment to report the \"mean ± std\" in Tab. 2. It can be seen that our models can outperform other methods over all these chosen widely adopted architectures with" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.958 + ], + "angle": 0, + "content": "19425" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.294, + 0.089, + 0.677, + 0.105 + ], + "angle": 0, + "content": "Table 3: Comparison with SoTA methods on CIFAR-100." + }, + { + "type": "table", + "bbox": [ + 0.16, + 0.116, + 0.812, + 0.569 + ], + "angle": 0, + "content": "
DatasetMethodTypeArchitectureTimestepAccuracy
CIFAR-100SpikeNorm [46]ANN2SNNResNet20250064.09%
RMP [23]ANN2SNNResNet20204867.82%
Hybrid-Train [45]Hybrid trainingVGG1112567.90%
IM-Loss [15]SNN trainingVGG16570.18%
Joint A-SNN [19]SNN trainingResNet18477.39%
ResNet34479.76%
Dspike [38]SNN trainingResNet20271.68%
473.35%
674.24%
TET [7]SNN trainingResNet19272.87%
474.47%
674.72%
RecDis-SNN [20]SNN trainingResNet19474.10%
VGG16569.88%
InfLoR-SNN [16]SNN trainingResNet20571.19%
VGG16571.56%
Real Spike [21]SNN trainingResNet20566.60%
VGG16570.62%
GLIF [60]SNN trainingResNet19275.48%
477.05%
TEBN [10]SNN trainingResNet19275.86%
476.13%
676.41%
MPBNSNN trainingVGG16474.74%±0.11
ResNet19178.71%±0.10
279.51%±0.07
ResNet20270.79%±0.08
472.30%±0.08
" + }, + { + "type": "table_caption", + "bbox": [ + 0.3, + 0.582, + 0.669, + 0.598 + ], + "angle": 0, + "content": "Table 4: Comparison with SoTA methods on ImageNet." + }, + { + "type": "table", + "bbox": [ + 0.172, + 0.609, + 0.8, + 0.774 + ], + "angle": 0, + "content": "
DatasetMethodTypeArchitectureTimestepAccuracy
ImageNetSTBP-tdBN [62]SNN trainingResNet34663.72%
TET [7]SNN trainingResNet34664.79%
MS-ResNet [27]SNN trainingResNet18663.10%
OTT [54]SNN trainingResNet34663.10%
Real Spike [21]SNN trainingResNet18463.68%
SEW ResNet [11]SNN trainingResNet18463.18%
ResNet34467.04%
MPBNSNN trainingResNet18463.14%±0.08
ResNet34464.71%±0.09
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.8, + 0.471, + 0.892 + ], + "angle": 0, + "content": "fewer time steps. For example, The accuracy of spiking ResNet19 trained with MPBN with only 1 time step can be up to \\(96.06\\%\\), while the Real Spike [21] needs 6 time steps to reach a comparable result and the RecDis-SNN [61] even still underperforms \\(0.51\\%\\) with 6 time steps. This superiority can also be observed in the results regarding the spiking" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.8, + 0.657, + 0.814 + ], + "angle": 0, + "content": "ResNet20 and VGG16." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "CIFAR-100. For CIFAR-100, we adopted the same settings as in CIFAR-10. The proposed MPBN also performs well on CIFAR-100. It can be seen that our method gets the best accuracy over all these networks even with fewer time steps. For instants, the ResNet19 trained with MPBN" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19426" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.282, + 0.089, + 0.687, + 0.105 + ], + "angle": 0, + "content": "Table 5: Comparison with SoTA methods on CIFAR10-DVS." + }, + { + "type": "table", + "bbox": [ + 0.155, + 0.116, + 0.819, + 0.284 + ], + "angle": 0, + "content": "
DatasetMethodTypeArchitectureTimestepAccuracy
CIFAR10-DVSRollout [33]RolloutDenseNet1066.80%
LIAF-Net [53]Conv3DLIAF-Net1071.70%
LIAF-Net [53]LIAFLIAF-Net1070.40%
STBP-tdBN [62]SNN trainingResNet191067.80%
RecDis-SNN [20]SNN trainingResNet191072.42%
Real Spike [21]SNN trainingResNet191072.85%
ResNet201078.00%
MPBNSNN trainingResNet191074.40%±0.20
ResNet201078.70%±0.10
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.307, + 0.47, + 0.367 + ], + "angle": 0, + "content": "can achieve \\(78.71\\%\\) top-1 accuracy with only 1 time step, which outperforms other SoTA methods such as TET, GLIF, TEBN, and RecDis-SNN even with 4 or 6 time steps about \\(1.66\\% -3.99\\%\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.368, + 0.47, + 0.579 + ], + "angle": 0, + "content": "ImageNet. On ImageNet, we used standard data normalization, random horizontal flipping, and cropping for data augmentation and trained the networks for 320 epochs as in [11]. The optimizer setting also keeps the same with CIFAR datasets. The results for ImageNet are presented in Tab. 4. It can be seen that the accuracy of our method is better than that of these recent SoTA methods, only relatively smaller compared with SEW ResNet [11] for spiking ResNet34. However, SEW ResNet is not a typical SNN model. It adopts the activation before addition form-based ResNet and its blocks will fire positive integer spikes. In this way, the event-driven and multiplication-addition transform advantages of SNNs will be lost. While we adopt the original ResNet, which fires standard binary spikes." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.58, + 0.47, + 0.686 + ], + "angle": 0, + "content": "CIFAR10-DVS. We also adopted the neuromorphic dataset, CIFAR10-DVS in the paper to verify the effectiveness of the MPBN. We also split the dataset into 9K training images and 1K test images, and resize them to \\(48 \\times 48\\) for data augmentation as in [51, 21]. The learning rate is 0.01 and other settings are the same as CIFAR-10. It can be seen that the MPBN also shows superiority in this dataset." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.694, + 0.303, + 0.709 + ], + "angle": 0, + "content": "5.2. Extension of the MPBN" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.717, + 0.47, + 0.853 + ], + "angle": 0, + "content": "In CNNs, the most widely used BN is channelwised. This is because element-wised BNs are very time-consuming and can not be folded into weights, otherwise, the channel-wised weight-sharing mechanism will be destroyed. However, the MPBN adopts the firing thresholdfolded manner and the firing threshold need not keep the same along the channels, therefore, MPBN can use the element-wised form freely. In this way, \\(V_{\\mathrm{th}}\\) will be transformed to element-wised ones as follows," + }, + { + "type": "equation", + "bbox": [ + 0.11, + 0.862, + 0.47, + 0.906 + ], + "angle": 0, + "content": "\\[\n(\\tilde {\\boldsymbol {V}} _ {\\mathrm {t h}}) _ {i, j, k} = \\frac {(V _ {\\mathrm {t h}} - \\beta_ {i , j , k}) \\sqrt {\\sigma_ {i , j , k} ^ {2}}}{\\boldsymbol {\\lambda} _ {i , j , k}} + \\boldsymbol {\\mu} _ {i, j, k}, \\tag {13}\n\\]" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.306, + 0.892, + 0.336 + ], + "angle": 0, + "content": "Table 6: Comparison with learnable firing threshold methods." + }, + { + "type": "table", + "bbox": [ + 0.506, + 0.347, + 0.888, + 0.439 + ], + "angle": 0, + "content": "
DatasetMethodTime stepAccuracy
CIFAR-10channel-wised494.28%
element-wised494.42%
CIFAR-100channel-wised472.30%
element-wised472.49%
" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.461, + 0.892, + 0.629 + ], + "angle": 0, + "content": "where \\((\\tilde{V}_{\\mathrm{th}})_{i,j,k}\\) is the transformed firing threshold of the neuron comes from \\(i\\)-th channel in the spatial position \\((j,k)\\). To investigate the performance of the element-wised MPBN, here we also provide a comparison of the vanilla MPBN and its extension. The results of top-1 accuracy of the spiking ResNet20 with 4 time steps on CIFAR datasets are shown in Tab. 6. Though the two versions all perform well, the element-wised MPBN is relatively better than the channel-wised MPBN. This may be because element-wised MPBN can learn more firing threshold values, which means a richer representation ability for SNNs." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.641, + 0.62, + 0.657 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.666, + 0.892, + 0.817 + ], + "angle": 0, + "content": "In the paper, we advocated adding the MPBN before the firing function to regulate the disturbed data flow again. We also provided a training-inference-decoupled reparameterization technique to fold the trained MPBN into the firing threshold to eliminate the extra time burden induced by MPBN in the inference time. Furthermore, the channel-wised and element-wised MPBN in different granularities were explored. Extensive experiments verified that the proposed MPBN can consistently achieve good performance." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.831, + 0.652, + 0.848 + ], + "angle": 0, + "content": "Acknowledgment" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "This work is supported by grants from the National Natural Science Foundation of China under contracts No.12202412 and No.12202413." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19427" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.079, + 0.09, + 0.176, + 0.107 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.47, + 0.24 + ], + "angle": 0, + "content": "[1] Filipp Akopyan, Jun Sawada, Andrew Cassidy, Rodrigo Alvarez-Icaza, John Arthur, Paul Merolla, Nabil Imam, Yutaka Nakamura, Pallab Datta, Gi-Joon Nam, Brian Taba, Michael Beakes, Bernard Brezzo, Jente Kuang, Rajit Manohar, W.P. Risk, Bryan Jackson, and Dharmendra Modha. Truenorth: Design and tool flow of a 65 mw 1 million neuron programmable neurosynaptic chip. Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on, 34:1537-1557, 10 2015. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.242, + 0.47, + 0.283 + ], + "angle": 0, + "content": "[2] Jimmy Lei Ba, Jamie Ryan Kiros, and Geoffrey E Hinton. Layer normalization. arXiv preprint arXiv:1607.06450, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.285, + 0.47, + 0.327 + ], + "angle": 0, + "content": "[3] G. Bellec, D. Salaj, A. Subramoney, R. Legenstein, and W. Maass. Long short-term memory and learning-to-learn in networks of spiking neurons, 2018. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.328, + 0.47, + 0.37 + ], + "angle": 0, + "content": "[4] Xiang Cheng, Yunzhe Hao, Jiaming Xu, and Bo Xu. Lisnn: Improving spiking neural networks with lateral interactions for robust object recognition. pages 1519-1525, 07 2020. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.372, + 0.47, + 0.44 + ], + "angle": 0, + "content": "[5] Mike Davies, Narayan Srinivasa, Tsung-Han Lin, Gautham Chinya, Andrew Lines, Andreas Wild, Hong Wang, and Deepak Mathaikutty. Loihi: A neuromorphic manycore processor with on-chip learning. IEEE Micro, 38:82 - 99, 01 2018. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.442, + 0.47, + 0.485 + ], + "angle": 0, + "content": "[6] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Fei-Fei Li. Imagenet: a large-scale hierarchical image database. pages 248-255, 06 2009. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.486, + 0.47, + 0.542 + ], + "angle": 0, + "content": "[7] Shikuang Deng, Yuhang Li, Shanghang Zhang, and Shi Gu. Temporal efficient training of spiking neural network via gradient re-weighting. In International Conference on Learning Representations, 2022. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.543, + 0.47, + 0.584 + ], + "angle": 0, + "content": "[8] Terrance DeVries and Graham W. Taylor. Improved regularization of convolutional neural networks with cutout, 2017. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.586, + 0.47, + 0.614 + ], + "angle": 0, + "content": "[9] Travis DeWolf. Spiking neural networks take control. Science Robotics, 6(58):eabk3268, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.079, + 0.615, + 0.47, + 0.685 + ], + "angle": 0, + "content": "[10] Chaoteng Duan, Jianhao Ding, Shiyan Chen, Zhaofei Yu, and Tiejun Huang. Temporal effective batch normalization in spiking neural networks. In Alice H. Oh, Alekh Agarwal, Danielle Belgrave, and Kyunghyun Cho, editors, Advances in Neural Information Processing Systems, 2022. 1, 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.079, + 0.687, + 0.47, + 0.728 + ], + "angle": 0, + "content": "[11] Wei Fang, Zhaofei Yu, Yanqi Chen, Tiejun Huang, and Yonghong Tian. Deep residual learning in spiking neural networks. 2021. 2, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.079, + 0.729, + 0.47, + 0.785 + ], + "angle": 0, + "content": "[12] Wei Fang, Zhaofei yu, Yanqi Chen, Timothee Masquelier, Tiejun Huang, and Yonghong Tian. Incorporating learnable membrane time constant to enhance learning of spiking neural networks. 08 2021. 1, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.079, + 0.786, + 0.47, + 0.815 + ], + "angle": 0, + "content": "[13] Samanwoy Ghosh-Dastidar and Hojjat Adeli. Spiking neural networks. Int. J. Neural Syst., 19:295-308, 08 2009. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.079, + 0.816, + 0.47, + 0.857 + ], + "angle": 0, + "content": "[14] Yufei Guo and Yuanpei Chen. Neuroclip: Neuromorphic data understanding by clip and snn. arXiv preprint arXiv:2306.12073, 2023. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.079, + 0.858, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[15] Yufei Guo, Yuanpei Chen, Liwen Zhang, Xiaode Liu, Yinglei Wang, Xuhui Huang, and Zhe Ma. IM-loss: Information maximization loss for spiking neural networks. In Alice H." + }, + { + "type": "list", + "bbox": [ + 0.079, + 0.116, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "Oh, Alekh Agarwal, Danielle Belgrave, and Kyunghyun Cho, editors, Advances in Neural Information Processing Systems, 2022. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.136, + 0.892, + 0.219 + ], + "angle": 0, + "content": "[16] Yufei Guo, Yuanpei Chen, Liwen Zhang, YingLei Wang, Xiaode Liu, Xinyi Tong, Yuanyuan Ou, Xuhui Huang, and Zhe Ma. Reducing information loss for spiking neural networks. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XI, pages 36-52. Springer, 2022. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.221, + 0.892, + 0.261 + ], + "angle": 0, + "content": "[17] Yufei Guo, Xuhui Huang, and Zhe Ma. Direct learning-based deep spiking neural networks: a review. Frontiers in Neuroscience, 17:1209795, 2023. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.263, + 0.892, + 0.331 + ], + "angle": 0, + "content": "[18] Yufei Guo, Xiaode Liu, Yuanpei Chen, Liwen Zhang, Wei-hang Peng, Yuhan Zhang, Xuhui Huang, and Zhe Ma. Rmp-loss: Regularizing membrane potential distribution for spiking neural networks. arXiv preprint arXiv:2308.06787, 2023.2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.333, + 0.892, + 0.403 + ], + "angle": 0, + "content": "[19] Yufei Guo, Weihang Peng, Yuanpei Chen, Liwen Zhang, Xiaode Liu, Xuhui Huang, and Zhe Ma. Joint a-snn: Joint training of artificial and spiking neural networks via self-distillation and weight factorization. Pattern Recognition, page 109639, 2023. 1, 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.405, + 0.892, + 0.488 + ], + "angle": 0, + "content": "[20] Yufei Guo, Xinyi Tong, Yuanpei Chen, Liwen Zhang, Xiaode Liu, Zhe Ma, and Xuhui Huang. Recdis-snn: Rectifying membrane potential distribution for directly training spiking neural networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 326-335, June 2022. 2, 3, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.49, + 0.892, + 0.559 + ], + "angle": 0, + "content": "[21] Yufei Guo, Liwen Zhang, Yuanpei Chen, Xinyi Tong, Xiaode Liu, YingLei Wang, Xuhui Huang, and Zhe Ma. Real spike: Learning real-valued spikes for spiking neural networks. In European Conference on Computer Vision, pages 52-68. Springer, 2022. 1, 3, 4, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.56, + 0.892, + 0.602 + ], + "angle": 0, + "content": "[22] Bing Han and Kaushik Roy. Deep spiking neural network: Energy efficiency through time based coding. In ECCV, pages 388-404. Springer, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.603, + 0.892, + 0.658 + ], + "angle": 0, + "content": "[23] Bing Han, Gopalakrishnan Srinivasan, and Kaushik Roy. Rmp-snn: Residual membrane potential neuron for enabling deeper high-accuracy and low-latency spiking neural network. pages 13555–13564, 06 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.66, + 0.892, + 0.715 + ], + "angle": 0, + "content": "[24] Yunzhe Hao, Xuhui Huang, Meng Dong, and Bo Xu. A biologically plausible supervised learning method for spiking neural networks using the symmetric stdp rule. Neural Networks, 121, 09 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.716, + 0.892, + 0.758 + ], + "angle": 0, + "content": "[25] Zecheng Hao, Tong Bu, Jianhao Ding, Tiejun Huang, and Zhaofei Yu. Reducing ann-snn conversion error through residual membrane potential, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.759, + 0.892, + 0.801 + ], + "angle": 0, + "content": "[26] Zecheng Hao, Jianhao Ding, Tong Bu, Tiejun Huang, and Zhaofei Yu. Bridging the gap between anns and snns by calibrating offset spikes, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.802, + 0.892, + 0.844 + ], + "angle": 0, + "content": "[27] Yifan Hu, Yujie Wu, Lei Deng, and Guoqi Li. Advancing residual learning towards powerful deep spiking neural networks. arXiv preprint arXiv:2112.08954, 2021. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.845, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[28] Shin-ichi Ikegawa, Ryuji Saiin, Yoshihide Sawada, and Naotake Natori. Rethinking the role of normalization and residual blocks for spiking neural networks. Sensors, 22(8), 2022. 1, 3" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19428" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[29] Sergey Ioffe and Christian Szegedy. Batch normalization: Accelerating deep network training by reducing internal covariate shift. In International conference on machine learning, pages 448-456. PMLR, 2015. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.151, + 0.47, + 0.219 + ], + "angle": 0, + "content": "[30] Seijoon Kim, Seongsik Park, Byunggook Na, and Sungroh Yoon. Spiking-yolo: spiking neural network for energy-efficient object detection. In Proceedings of the AAAI conference on artificial intelligence, volume 34, pages 11270-11277, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.222, + 0.47, + 0.262 + ], + "angle": 0, + "content": "[31] Y. Kim and P. Panda. Revisiting batch normalization for training low-latency deep spiking neural networks from scratch, 2020. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.266, + 0.469, + 0.293 + ], + "angle": 0, + "content": "[32] Alex Krizhevsky, Vinod Nair, and Geoffrey Hinton. Cifar-10 (canadian institute for advanced research). 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.296, + 0.469, + 0.35 + ], + "angle": 0, + "content": "[33] Alexander Kugele, Thomas Pfeil, Michael Pfeiffer, and Elisabetta Chicca. Efficient processing of spatio-temporal data streams with spiking neural networks. Frontiers in Neuroscience, 14:439, 05 2020. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.354, + 0.469, + 0.408 + ], + "angle": 0, + "content": "[34] Chankyu Lee, Syed Sarwar, Priyadarshini Panda, Gopalakrishnan Srinivasan, and Kaushik Roy. Enabling spike-based backpropagation for training deep neural network architectures. Frontiers in Neuroscience, 14:119, 02 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.412, + 0.469, + 0.451 + ], + "angle": 0, + "content": "[35] Hongmin Li. Cifar10-dvs: An event-stream dataset for object classification. Frontiers in Neuroscience, 11, 05 2017. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.455, + 0.469, + 0.509 + ], + "angle": 0, + "content": "[36] Hao Li, Zheng Xu, Gavin Taylor, Christoph Studer, and Tom Goldstein. Visualizing the loss landscape of neural nets. Advances in neural information processing systems, 31, 2018. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.513, + 0.469, + 0.553 + ], + "angle": 0, + "content": "[37] Yuhang Li, Shikuang Deng, Xin Dong, and et al. A free lunch from ann: Towards efficient, accurate spiking neural networks calibration. In ICML, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.557, + 0.469, + 0.625 + ], + "angle": 0, + "content": "[38] Yuhang Li, Yufei Guo, Shanghang Zhang, Shikuang Deng, Yongqing Hai, and Shi Gu. Differentiable spike: Rethinking gradient-descent for training spiking neural networks. Advances in Neural Information Processing Systems, 34, 2021. 2, 4, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.629, + 0.469, + 0.669 + ], + "angle": 0, + "content": "[39] S. A. Lobov and et al. Spatial properties of stdp in a spiking neural network enable controlling a mobile robot. Frontiers in Neuroscience, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.673, + 0.469, + 0.713 + ], + "angle": 0, + "content": "[40] Ping Luo, Jiamin Ren, Zhanglin Peng, Ruimao Zhang, and Jingyu Li. Differentiable learning-to-normalize via switchable normalization, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.716, + 0.469, + 0.771 + ], + "angle": 0, + "content": "[41] Mitchell A Nahmias, Bhavin J Shastri, Alexander N Tait, and Paul R Prucnal. A leaky integrate-and-fire laser neuron for ultrafast cognitive computing. IEEE journal of selected topics in quantum electronics, 19(5):1-12, 2013. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.774, + 0.469, + 0.856 + ], + "angle": 0, + "content": "[42] Jing Pei, Lei Deng, Sen Song, Mingguo Zhao, Youhui Zhang, Shuang Wu, Guanrui Wang, Zhe Zou, Zhenzhi Wu, Wei He, Feng Chen, Ning Deng, Si Wu, Yu Wang, Yujie Wu, Zheyu Yang, Cheng Ma, Guoqi Li, Wentao Han, and L.P. Shi. Towards artificial general intelligence with hybrid tianjic chip architecture. Nature, 572:106, 08 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.859, + 0.469, + 0.9 + ], + "angle": 0, + "content": "[43] Peter, U., Diehl, Matthew, and Cook. Unsupervised learning of digit recognition using spike-timing-dependent plasticity. Frontiers in Computational Neuroscience, 9:99, 2015. 2" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[44] Nitin Rathi and Kaushik Roy. DIET-SNN: direct input encoding with leakage and threshold optimization in deep spiking neural networks. CoRR, abs/2008.03658, 2020. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.189 + ], + "angle": 0, + "content": "[45] Nitin Rathi, Gopalakrishnan Srinivasan, Priyadarshini Panda, and Kaushik Roy. Enabling deep spiking neural networks with hybrid conversion and spike timing dependent backpropagation. 05 2020. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.192, + 0.892, + 0.244 + ], + "angle": 0, + "content": "[46] Abhronil Sengupta, Yuting Ye, Robert Wang, Chiao Liu, and Kaushik Roy. Going deeper in spiking neural networks: Vgg and residual architectures. Frontiers in Neuroscience, 13, 02 2018. 2, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.247, + 0.892, + 0.314 + ], + "angle": 0, + "content": "[47] Jiangrong Shen, Qi Xu, Jian K Liu, Yueming Wang, Gang Pan, and Huajin Tang. Esl-snns: An evolutionary structure learning strategy for spiking neural networks. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 37, pages 86-93, 2023. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.316, + 0.892, + 0.355 + ], + "angle": 0, + "content": "[48] Dmitry Ulyanov, Andrea Vedaldi, and Victor Lempitsky. Instance normalization: The missing ingredient for fast stylization, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.358, + 0.892, + 0.44 + ], + "angle": 0, + "content": "[49] Siqi Wang, Tee Hiang Cheng, and Meng-Hiot Lim. LTMD: Learning improvement of spiking neural networks with learnable thresholding neurons and moderate dropout. In Alice H. Oh, Alekh Agarwal, Danielle Belgrave, and Kyunghyun Cho, editors, Advances in Neural Information Processing Systems, 2022. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.442, + 0.892, + 0.481 + ], + "angle": 0, + "content": "[50] Yujie Wu, Lei Deng, and et al. Spatio-temporal backpropagation for training high-performance spiking neural networks. Frontiers in neuroscience, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.484, + 0.892, + 0.537 + ], + "angle": 0, + "content": "[51] Yujie Wu, Lei Deng, Guoqi Li, Jun Zhu, Yuan Xie, and L.P. Shi. Direct training for spiking neural networks: Faster, larger, better. Proceedings of the AAAI Conference on Artificial Intelligence, 33:1311-1318, 07 2019. 1, 2, 4, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.539, + 0.892, + 0.58 + ], + "angle": 0, + "content": "[52] Yuxin Wu and Kaiming He. Group normalization. In Proceedings of the European conference on computer vision (ECCV), pages 3-19, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.582, + 0.892, + 0.649 + ], + "angle": 0, + "content": "[53] Zhenzhi Wu, Hehui Zhang, Yihan Lin, Guoqi Li, Meng Wang, and Ye Tang. Liaf-net: Leaky integrate and analog fire network for lightweight and efficient spatiotemporal information processing. IEEE Transactions on Neural Networks and Learning Systems, 33(11):6249-6262, 2022. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.651, + 0.892, + 0.691 + ], + "angle": 0, + "content": "[54] Mingqing Xiao, Qingyan Meng, Zongpeng Zhang, Di He, and Zhouchen Lin. Online training through time for spiking neural networks. arXiv preprint arXiv:2210.04195, 2022. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.693, + 0.892, + 0.761 + ], + "angle": 0, + "content": "[55] Rong Xiao, Yu Wan, Baosong Yang, Haibo Zhang, Huajin Tang, Derek F Wong, and Boxing Chen. Towards energy-preserving natural language understanding with spiking neural networks. IEEE/ACM Transactions on Audio, Speech, and Language Processing, 31:439-447, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.763, + 0.892, + 0.816 + ], + "angle": 0, + "content": "[56] Qi Xu, Yaxin Li, Xuanye Fang, Jiangrong Shen, Jian K Liu, Huajin Tang, and Gang Pan. Biologically inspired structure learning with reverse knowledge distillation for spiking neural networks. arXiv preprint arXiv:2304.09500, 2023. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.818, + 0.892, + 0.872 + ], + "angle": 0, + "content": "[57] Qi Xu, Yaxin Li, Jiangrong Shen, Jian K Liu, Huajin Tang, and Gang Pan. Constructing deep spiking neural networks from artificial neural networks with knowledge distillation. arXiv preprint arXiv:2304.05627, 2023. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.874, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[58] Qi Xu, Yaxin Li, Jiangrong Shen, Pingping Zhang, Jian K Liu, Huajin Tang, and Gang Pan. Hierarchical spiking-based" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19429" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.134 + ], + "angle": 0, + "content": "model for efficient image classification with enhanced feature extraction and encoding. IEEE Transactions on Neural Networks and Learning Systems, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.47, + 0.19 + ], + "angle": 0, + "content": "[59] Qi Xu, Jiangrong Shen, Xuming Ran, Huajin Tang, Gang Pan, and Jian K Liu. Robust transcoding sensory information with neural spikes. IEEE Transactions on Neural Networks and Learning Systems, 33(5):1935-1946, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.192, + 0.47, + 0.246 + ], + "angle": 0, + "content": "[60] Xingting Yao, Fanrong Li, Zitao Mo, and Jian Cheng. Glif: A unified gated leaky integrate-and-fire neuron for spiking neural networks. arXiv preprint arXiv:2210.13768, 2022. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.249, + 0.47, + 0.288 + ], + "angle": 0, + "content": "[61] Wenrui Zhang and Peng Li. Temporal spike sequence learning via backpropagation for deep spiking neural networks. 02 2020. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.291, + 0.47, + 0.332 + ], + "angle": 0, + "content": "[62] Hanle Zheng, Yujie Wu, Lei Deng, Yifan Hu, and Guoqi Li. Going deeper with directly-trained larger spiking neural networks. 10 2020. 1, 3, 6, 7, 8" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.332 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19430" + } + ] +] \ No newline at end of file diff --git a/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/cc22facf-9790-4a7c-8861-ea4adecda7ac_origin.pdf b/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/cc22facf-9790-4a7c-8861-ea4adecda7ac_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..253a945e59658d0be41c094ee63df92e666efde3 --- /dev/null +++ b/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/cc22facf-9790-4a7c-8861-ea4adecda7ac_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:94f21d0e71abeca49028aac506c87e88fc47b0dd75c21cdbadaca1872eb7595d +size 1345331 diff --git a/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/full.md b/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/full.md new file mode 100644 index 0000000000000000000000000000000000000000..84dfd03ad4c321b6548b1a2030c7f005ac236018 --- /dev/null +++ b/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/full.md @@ -0,0 +1,356 @@ +# Membrane Potential Batch Normalization for Spiking Neural Networks + +Yufei Guo,\* Yuhan Zhang,\* Yuanpei Chen, Weihang Peng, Xiaode Liu, Liwen Zhang, Xuhui Huang, Zhe Ma\* Intelligent Science & Technology Academy of CASIC, China Scientific Research Laboratory of Aerospace Intelligent Systems and Technology, China + +# Abstract + +As one of the energy-efficient alternatives of conventional neural networks (CNNs), spiking neural networks (SNNs) have gained more and more interest recently. To train the deep models, some effective batch normalization (BN) techniques are proposed in SNNs. All these BNs are suggested to be used after the convolution layer as usually doing in CNNs. However, the spiking neuron is much more complex with the spatio-temporal dynamics. The regulated data flow after the BN layer will be disturbed again by the membrane potential updating operation before the firing function, i.e., the nonlinear activation. Therefore, we advocate adding another BN layer before the firing function to normalize the membrane potential again, called MPBN. To eliminate the induced time cost of MPBN, we also propose a training-inference-decoupled re-parameterization technique to fold the trained MPBN into the firing threshold. With the re-parameterization technique, the MPBN will not introduce any extra time burden in the inference. Furthermore, the MPBN can also adopt the element-wised form, while these BNs after the convolution layer can only use the channel-wised form. Experimental results show that the proposed MPBN performs well on both popular non-spiking static and neuromorphic datasets. + +# 1. Introduction + +Emerged as a biology-inspired method, spiking neural networks (SNNs) have received much attention in artificial intelligence and neuroscience recently [17, 13, 57, 56, 47, 58, 59]. SNNs deal with binary event-driven spikes as their activations and therefore the multiplications of activations and weights can be substituted for additions or only keeping silent. Benefitting from such a computation paradigm, SNNs derive extreme energy efficiency and run efficiently when implemented on neuromorphic hardware [1, 42, 5]. + +Despite the SNN has achieved great success in diverse fields including pattern recognition [12, 21, 19, 14], object detection [30], language processing [55], robotics [9], and so on, its development is deeply inspired by the experience of convolutional neural networks (CNNs) in many aspects. However, the spiking neuron model along with the rich spatio-temporal dynamic makes SNNs much different from CNNs, and directly transferring some experience of CNNs to SNNs without any modifications may be not a good idea. As one of the famous techniques in CNNs, the batch normalization(BN) technique shows great advantages. It can reduce the gradient exploding/vanishing problem, flatten the loss landscape, and reduce the internal covariate shift, thus being widely used in CNNs. There are also some works trying to apply normalization approaches in the SNN field to help model convergence. For example, inspired by BN in CNNs, NeuNorm [51] was proposed to normalize the data along the channel dimension. Considering that the temporal dimension is also important in SNNs, threshold-dependent batch normalization (tdBN) [62] then extended the scope of BN to the additional temporal dimension. Subsequently, to better depict the differences of data flow distributions in different time dimensions, the temporal batch normalization through time (BNTT) [31], postsynaptic potential normalization (PSP-BN) [28], and temporal effective batch normalization (TEBN) [10] that regulate the data flows with multiple BNs on different time steps were proposed. + +However, all these BNs proposed in SNNs are advised to be used after convolution layers as usually doing in CNNs. This ignores the fact that the nonlinear transformation in the SNN spiking neuron is much more complex than that of the ReLU neuron. In the spiking neuron, the data flow after the convolution layer will be first injected into the residual membrane potential (MP) coming from the previous time step to generate a new MP at the current time step. And then the neuron will fire a spike or keep silent still based on whether or not the new MP is up to the firing threshold. Obviously, though the data flow has been normalized by the BN after the convolution layer, it will be + +![](images/753c39a704f8c0eb5fca69152ad5cf5c19d1c3127871e3cc9636e26d81ea5f28.jpg) +Figure 1: The difference between our SNN with MPBN and the vanilla SNN. We add another BN layer after membrane potential updating (MPU) operation in the training. The MPBN can be folded into the firing threshold and then the homogenous firing threshold will be transformed into different ones. + +disturbed again by the residual MP in the membrane potential updating process. Therefore, we advocate also adding a BN layer after MP updating to regulate the data flow once again, called MPBN. Furthermore, we also propose a training-inference-decoupled re-parameterization technique in SNNs to fold the trained MPBN into the firing threshold. Hence, the MPBN will not induce any extra burden in the inference but a trivial burden in the training. The MPBN can be extended to channel-wised MPBN and element-wised MPBN further, which is very different from that of CNNs where only channel-wised normalization can be folded into weights. The difference between our SNN with MPBN and the vanilla SNN is illustrated in Fig. 1. Our main contributions are as follows: + +- We propose to add another BN layer after the membrane potential updating operation named MPBN to handle the data flow disturbance in the spiking neuron. The experiment shows that MPBN can flatten the loss landscape further, thus benefiting model convergence and task accuracy. +- We also propose a re-parameterization method to decouple the training-time SNN and the inference-time SNN. In specific, we propose a method to fold the trained MPBN parameter into the firing threshold. Therefore, MPBN can be seen as only training auxiliary manner free from burdens in the inference-time. This re-parameterization method is suitable for both channel-wised MPBN and element-wised MPBN. +- Extensive experiment results show that the SNN trained with the MPBN is highly effective compared + +with other state-of-the-art SNN models on both static and dynamic datasets, e.g., $96.47\%$ top-1 accuracy and $79.51\%$ top-1 accuracy are achieved on the CIFAR-10 and CIFAR-100 with only 2 time steps. + +# 2. Related Work + +# 2.1. Learning of Spiking Neural Networks + +There are three kinds of learning algorithms of SNNs, including unsupervised learning [43, 24], converting ANN to SNN (ANN2SNN) [46, 25, 26], and supervised learning [19, 38, 20]. Unsupervised learning adopts some biological mechanism to update the SNN model, i.e., the spiketiming-dependent plasticity (STDP) approach [39], thus being considered a biologically plausible method. However, STDP cannot help train large-scale networks yet, thus it is usually limited to small datasets and non-ideal performance. The ANN-SNN conversion approach [22, 37] obtains an SNN by reusing well-trained homogeneous ANN parameters and replacing the ReLU neuron with a spiking neuron. Since the ANN model is easier to train and reach high performance, the ANN-SNN conversion method provides an interesting way to generate an SNN in a short time with competitive performance. However, the converted SNN will lose the rich temporal dynamic behaviors and thus cannot handle neuromorphic datasets well. Supervised learning [11, 50, 18] adopts the surrogate gradient (SG) approach to train SNNs with error backpropagation. It can handle temporal data and provide decent performance with few time steps on the large-scale dataset, thus having received much attention recently. For a more detailed introduction, please refer to the recent SNN survey [17]. Our work falls under the supervised learning. + +# 2.2. Normalization in Spiking Neural Networks + +The batch normalization technique was originally introduced as a kind of training auxiliary method by [29] in CNNs. It uses the weight-summed input over a mini-batch of training cases to compute a mean and variance and then uses them to regulate the summed input. This simple operation can derive many benefits. i) It reduces the internal covariate shift (ICS), thus accelerating the training of a deep neural network. ii) It makes the network insensitive to the scale of the gradients, thus a higher learning rate can be chosen to accelerate the training. iii) It makes the network suitable for more nonlinearities by preventing the network from getting stuck in the saturated modes. With these advantages, more kinds of BNs were proposed, including layer normalization [2], group normalization [52], instance normalization [48], and switchable normalization [40]. + +There are also some works that modify and apply normalization approaches in the SNN field. For example, NeuNorm [51] also normalizes the feature map along the chan + +nel dimension like BN in CNNs. Recently, some methods were proposed to normalize the feature map from both the channel dimension and temporal dimension to take care of the spatio-temporal characteristics of the SNN, such as the threshold-dependent batch normalization (tdBN) [62]. It extends the scope of BN to the additional temporal dimension by adopting a 3DBN-like normalization method in CNNs. Note that, the tdBN can be folded into the weights, thus inducing no burden in the inference time. Nevertheless, NeuNorm and tdBN still use the shared parameters along the temporal dimension. Some works argued that the distributions of data in different time steps vary wildly and that using shared parameters is not a good choice. Subsequently, the temporal batch normalization through time (BNTT) [31], postsynaptic potential normalization (PSP-BN) [28], and temporal effective batch normalization (TEBN) [10] were proposed. These BNs regulate the data flow utilizing different parameters through time steps. Though these BNs with different BN parameters on different time steps can train more well-performed SNN models, their parameters can not be folded into the weights, thus will increase the computations and running time in the inference. + +Nevertheless, all these BNs in the SNN field are advised to be used after convolution layers. However, the data flow after the convolution layer will not be presented to the firing function directly but to the membrane potential updating function first. Hence, the data flow will be disturbed again before reaching the firing function. To this end, in this paper, we add another BN after the membrane potential updating function, called the MPBN to retain normalized data flow before the firing function. + +# 3. Preliminary + +# 3.1. Leaky Integrate-and-Fire Model + +Different from CNNs, SNNs use binary spikes to transmit information. In the paper, we use the widely used Leaky-Integrate-and-Fire (LIF) neuron model [41] to introduce the unique spatial-temporal dynamic of the spiking model. First, we introduce the notation rules used here as follows. Vectors or tensors are denoted by bold italic letters, i.e., $\mathbf{x}$ and $\mathbf{o}$ represent the input and output variables respectively. Matrices are denoted by bold capital letters. For instance, $\mathbf{W}$ is the weight matrix. The constant is denoted by small letters. + +In LIF, the membrane potential is updated by + +$$ +\boldsymbol {u} ^ {(t + 1), \text {p r e}} = \tau \boldsymbol {u} ^ {(t)} + \boldsymbol {c} ^ {(t + 1)}, \text {w h e r e} \boldsymbol {c} ^ {(t + 1)} = \mathbf {W} \boldsymbol {x} ^ {(t + 1)}, \tag {1} +$$ + +where $\pmb{u}$ represents the membrane potential and $\pmb{u}^{(t + 1),\mathrm{pre}}$ is the updated membrane potential at time step $t + 1$ , $\pmb{c}^{(t + 1)}$ is the pre-synaptic input at time step $t + 1$ , which is charged + +by weight-summed input spikes $\pmb{x}^{(t + 1)}$ , and $\tau$ is a constant within (0, 1), which controls the leakage of the membrane potential. Then, when the updated membrane potential $\pmb{u}^{(t + 1),\mathrm{pre}}$ is up to the firing threshold $V_{\mathrm{th}}$ , the LIF spiking neuron will fire a spike as below, + +$$ +\boldsymbol {o} ^ {(t + 1)} = \left\{ \begin{array}{l l} 1 & \text {i f} \boldsymbol {u} ^ {(t + 1), \text {p r e}} > V _ {\text {t h}} \\ 0 & \text {o t h e r w i s e} \end{array} , \right. \tag {2} +$$ + +$$ +\boldsymbol {u} ^ {(t + 1)} = \boldsymbol {u} ^ {(t + 1), \text {p r e}} \cdot (1 - \boldsymbol {o} ^ {(t + 1)}). +$$ + +After firing, the spike output $\pmb{o}^{(t + 1)}$ at time step $t + 1$ will be transmitted to the next layer and become its input. At the same time, the updated membrane potential will be reset to zero and becomes $\pmb{u}^{(t + 1)}$ to join the neuron processing at the next time step. + +The Classifier in the SNN. In a classification model, the final output is used to compute the Softmax and predict the desired class object. In an SNN model, if we also use LIF neurons at the output layer to fire spikes and use the number of spikes to compute the probability, too much information will be lost. Therefore, we only integrate the output and do not fire them across time, as doing in recent work [20, 21, 12]. + +$$ +\boldsymbol {o} _ {\text {o u t}} = \frac {1}{T} \sum_ {t = 1} ^ {T} \boldsymbol {c} _ {\text {o u t}} ^ {(t)} = \frac {1}{T} \sum_ {t = 1} ^ {T} \mathbf {W} \boldsymbol {x} ^ {(t)}. \tag {3} +$$ + +Then, the cross-entropy loss is computed based on the true label and $\operatorname{Softmax}(\pmb{o}_{\mathrm{out}})$ . + +# 3.2. Batch Normalization in SNNs + +Batch normalization can effectively reduce the internal covariate shift and alleviate the gradient vanishing or explosion problem for training networks, thus having been widely used in CNNs. Fortunately, BN can also be used in SNNs. Considering a spiking neuron with input $\pmb{c} = \{c^{(1)}, c^{(2)}, \dots, c^{(t)}, \dots\}$ , where $t$ is the time step, BN regulate the input at each time step as follows, + +$$ +\tilde {\boldsymbol {c}} _ {i} ^ {(t)} = \frac {\boldsymbol {c} _ {i} ^ {(t)} - \boldsymbol {\mu} _ {i}}{\sqrt {\boldsymbol {\sigma} _ {i} ^ {2} + \epsilon}}, \tag {4} +$$ + +where $c_{i}^{(t)}$ is the input in $i$ -th channel at $t$ -th time step, $\mu_{i}$ and $\sigma_{i}$ are the mean and variance of input in channel dimension, and $\epsilon$ is a small constant to avoid denominator being zero. To ensure BN can represent the identity transformation, the normalized vector $\tilde{c}_{i}^{(t)}$ is scaled and shifted in a learning manner as follows, + +$$ +\operatorname {B N} \left(\boldsymbol {c} _ {i} ^ {(t)}\right) = \boldsymbol {\lambda} _ {i} \tilde {\boldsymbol {c}} _ {i} ^ {(t)} + \boldsymbol {\beta} _ {i}, \tag {5} +$$ + +where $\lambda_{i}$ and $\beta_{i}$ are channel-wised learnable parameters. + +# 4. Methodology + +This section first introduces the specific form of membrane potential batch normalization. Then the reparameterization technique that how to fold the MPBN into $V_{\mathrm{th}}$ will be introduced in detail. Next, some key details for training the SNN and the pseudocode for the training and inference of our SNN will be given. Finally, we will provide plenty of ablation studies and the comparison of the loss landscape of the models with or without MPBN to show the effectiveness of the proposed method. + +# 4.1. Membrane Potential Batch Normalization + +As abovementioned, we argue that though the data flow has been normalized by the BN after the convolution layer, it will be disturbed again by the membrane potential updating operation. To better depict this, we give the vanilla form of LIF neuron with BN first as follows, + +$$ +\boldsymbol {u} ^ {(t + 1), \text {p r e}} = \tau \boldsymbol {u} ^ {(t)} + \mathrm {B N} (\mathbf {W} \boldsymbol {x} ^ {(t + 1)}), \tag {6} +$$ + +where $\tau$ is 0.25 in the paper following [21, 38, 4]. To regulate the disturbed data flow once again, We further embed another BN after the membrane potential updating operation, called MPBN. The LIF neuron with MPBN can be updated as + +$$ +\tilde {\boldsymbol {u}} ^ {(t + 1), \text {p r e}} = \operatorname {M P B N} (\boldsymbol {u} ^ {(t + 1), \text {p r e}}). \tag {7} +$$ + +Obviously, $\pmb{u}^{(t + 1),\mathrm{pre}}$ will be scaled and sifted, and some $\pmb{u}^{(t + 1),\mathrm{pre}}$ less than $V_{\mathrm{th}}$ may be greater than $V_{\mathrm{th}}$ with MPBN and vice versa. This is abhorrent with the biology and MPBN will cause some extra computation burden in the inference compared with the vanilla one. To solve this problem, we also propose a training-inference-decoupled re-parameterization technique here. + +# 4.2. Re-parameterization + +With MPBN, the firing function will be updated as + +$$ +\boldsymbol {o} ^ {(t + 1)} = \left\{ \begin{array}{l l} 1 & \text {i f M P B N} (\boldsymbol {u} ^ {(t + 1), \text {p r e}}) > V _ {\text {t h}} \\ 0 & \text {o t h e r w i s e} \end{array} . \right. \tag {8} +$$ + +If we unfold the MPBN, the above equation will be reorganized as + +$$ +\boldsymbol {o} _ {i} ^ {(t + 1)} = \left\{ \begin{array}{l l} 1 & \text {i f} \lambda_ {i} \frac {\boldsymbol {u} _ {i} ^ {(t + 1) , \text {p r e}} - \boldsymbol {\mu} _ {i}}{\sqrt {\sigma_ {i} ^ {2}}} + \beta_ {i} > V _ {\text {t h}} \\ 0 & \text {o t h e r w i s e} \end{array} . \right. \tag {9} +$$ + +By folding the MPBN to $V_{\mathrm{th}}$ , the firing function will be further updated as + +$$ +\boldsymbol {o} _ {i} ^ {(t + 1)} = \left\{ \begin{array}{l l} 1 & \text {i f} \boldsymbol {u} ^ {(t + 1), \text {p r e}} > \left(\tilde {\boldsymbol {V}} _ {\mathrm {t h}}\right) _ {i} \\ 0 & \text {o t h e r w i s e} \end{array} , \right. \tag {10} +$$ + +where $(\tilde{V}_{\mathrm{th}})_i = \frac{(V_{\mathrm{th}} - \beta_i)\sqrt{\sigma_i^2}}{\lambda_i} +\pmb {\mu}_i$ + +Algorithm 1 Training and inference of our SNN. + +# Training + +Input: An SNN to be trained with MPBN; training dataset; total training iteration: $I_{\text{train}}$ . + +Output: The well-trained SNN. + +1: for all $i = 1,2,\ldots ,{I}_{\text{train }}$ iteration do +2: Get mini-batch training data, $\pmb{x}_{\mathrm{in}}(i)$ and class label, $\pmb{y}(i)$ ; +3: Feed the $\pmb{x}_{\mathrm{in}}(i)$ into the SNN and regulate the data flow by BN and MPBN; +4: Calculate the SNN output, $\pmb{o}_{\mathrm{out}}(i)$ by Eq. 3; +5: Compute classification loss $L_{\mathrm{CE}}$ = $\mathcal{L}_{\mathrm{CE}}(\pmb{o}_{\mathrm{out}}(i),\pmb{y}(i));$ +6: Calculate the gradient w.r.t. W by Eq. 11; +7: Update $\mathbf{W}$ : $(\mathbf{W} \leftarrow \mathbf{W} - \eta \frac{\partial L}{\partial \mathbf{W}})$ where $\eta$ is learning rate. +8: end for + +# Re-parameterization + +Input: The trained SNN with MPBN; total number of MPBN: $n$ . + +Output: The re-parameterized trained SNN without MPBN but diverse $V_{\mathrm{th}}$ . + +1: for all $i = 1,2,\ldots ,n$ number do +2: Fold the parameters of $i$ -th MPBN into $i$ -th $V_{\mathrm{th}}$ by Eq. 10; +3: end for + +# Inference + +Input: The re-parameterized trained SNN; test dataset; total test iteration: $I_{\mathrm{test}}$ . + +Output: The output. + +1: for all $i = 1,2,\ldots ,{I}_{\text{test }}$ iteration do +2: Get mini-batch test data, $\mathbf{x}_{\mathrm{in}}(i)$ and class label, $\mathbf{y}(i)$ in test dataset; +3: Feed the $\pmb{x}_{\mathrm{in}}(i)$ into the reparameterized SNN without MPBN; +4: Calculate the SNN output, $\pmb{o}_{\mathrm{out}}(i)$ by Eq. 3; +5: Compare the classification factor $\pmb{o}_{\mathrm{out}}(i)$ and $\pmb{y}(i)$ for classification. + +# 6: end for + +It can be seen that by absorbing some parameters from MPBN, $V_{\mathrm{th}}$ will be transformed to another channel-wised $(\tilde{V}_{\mathrm{th}})_i$ . In this way, the extra computation burden caused by MPBN will be eliminated again in the inference time. Furthermore, the diversity of the spiking neuron will be improved with abundant firing parameters as the learnable firing threshold in other work [3, 49]. + +# 4.3. Training Framework + +In the paper, the spatial-temporal backpropagation (STBP) algorithm [51] is adopted to train the SNN mod + +![](images/7dc6ade33d1190bb6aa0db95652147e83bc5f7dcd28ced2428a6446947c4bdb7.jpg) +(a) CIFAR-10 + +![](images/9532ddd02be7274b71ff4db54919280bc180d4795662696cb7b42e6d766f2355.jpg) +(b) CIFAR-100 +Figure 2: The accuracy curves of spiking ResNet20 with or without MPBN using 2 time steps on CIFAR-10 (left) and CIFAR-100 (right). The MPBN based SNNs obviously enjoy higher accuracy and easier convergence. + +els. STBP treats the SNN model as a self-recurrent neural network thus enabling an error backpropagation mechanism following the same principles as in CNNs. However, there is still a problem impeding the direct training of SNNs. To demonstrate this problem, we formulate the gradient at the layer $l$ by the chain rule, given by + +$$ +\frac {\partial L}{\partial \mathbf {W} ^ {l}} = \sum_ {t} \left(\frac {\partial L}{\partial \boldsymbol {o} ^ {(t) , l}} \frac {\partial \boldsymbol {o} ^ {(t) , l}}{\partial \boldsymbol {u} ^ {(t) , l}} + \frac {\partial L}{\partial \boldsymbol {u} ^ {(t + 1) , l}} \frac {\partial \boldsymbol {u} ^ {(t + 1) , l}}{\partial \boldsymbol {u} ^ {(t) , l}}\right) \frac {\partial \boldsymbol {u} ^ {(t) , l}}{\partial \mathbf {W} ^ {l}}, \tag {11} +$$ + +where $\frac{\partial\pmb{o}^{(t),l}}{\partial\pmb{u}^{(t),l}}$ is the gradient of firing function at at $t$ -th time step in $l$ -th layer. Obviously, the non-differentiable firing activity of the spiking neuron will result in zero gradients everywhere, while infinity at $V_{\mathrm{th}}$ . Therefore, the gradient descent $(\mathbf{W}^l\gets \mathbf{W}^l -\eta \frac{\partial L}{\partial\mathbf{W}^l})$ either freezes or updates to infinity in the backpropagation. To handle this problem, here, we also adopt the commonly used STE surrogate gradients as doing in other surrogate gradients (SG) methods [44, 20]. Mathematically, it is defined as: + +$$ +\frac {d \boldsymbol {o}}{d \boldsymbol {u}} = \left\{ \begin{array}{l l} 1, & \text {i f} 0 \leq \boldsymbol {u} \leq 1 \\ 0, & \text {o t h e r w i s e} \end{array} \right.. \tag {12} +$$ + +Then, the SNN model can be trained end-to-end. The training and inference of our SNN are detailed in Algo. 1. + +# 4.4. Ablation Study + +To verify the effectiveness of the MPBN, a lot of ablative studies using spiking ResNet20 architecture along with different time steps were conducted on the CIFAR-10 and CIFAR-100 datasets. The results of top-1 accuracy of these models are shown in Tab. 1. It's can be seen that the test accuracy of the SNNs with MPBN is always higher than these vanilla counterparts. For example, the accuracy of baseline SNN with 1 time step is $90.40\%$ , while with MPBN, it will increase up to $92.22\%$ , which is a huge improvement (more than $2.0\%$ ) in the SNN field. Moreover, we also show the test accuracy curves of ResNet20 using MPBN and its + +Table 1: Ablation experiments for MPBN. + +
DatasetMethodTime stepAccuracy
CIFAR-10baseline190.40%
w/ MPBN192.22%
baseline292.80%
w/ MPBN293.54%
baseline493.85%
w/ MPBN494.28%
CIFAR-100baseline167.94%
w/ MPBN168.36%
baseline270.18%
w/ MPBN270.79%
baseline471.77%
w/ MPBN472.30%
+ +![](images/6863b9ac56d0690ab487204ebbbc6ece166455ad1ad0c842df883d19db9f0313.jpg) +(a) MPBN +Figure 3: The 1D loss landscape of spiking ResNet20 with and without MPBN. + +![](images/5e6dea99328c8638d89687bd97a184f1994ea19a3d6e40db450ad2569f5c2e5e.jpg) +(b) Vanilla + +vanilla counterpart with 2 time steps on CIFAR-10/100 during training in Fig. 2. It can be observed obviously that the SNNs with MPBN also perform better on convergence speed. To sum up, the proposed MPBN can both improve accuracy and convergence speed, which are very important aspects in deep learning. + +# 4.5. Loss Landscape + +We further inspect the 1D loss landscapes [36] of the SNNs with or without MPBN using spiking ResNet20 architecture in 2 time steps to show why the MPBN can improve accuracy and convergence speed in Fig. 3. It can be observed that the loss landscape of the SNN model with MPBN is flatter than that of the SNN without MPBN. This indicates that the MPBN makes the landscape of the corresponding optimization problem smoother [36], thus making the gradients more predictive and network faster convergence. The results here provide convincing evidence for ablation studies in Section 4.4. + +# 5. Experiments + +In this section, abundant experiments were conducted to verify the effectiveness of the MPBN using widely-used spiking ResNet20 [44, 46], VGG16 [44], ResNet18 [11], + +Table 2: Comparison with SoTA methods on CIFAR-10. + +
DatasetMethodTypeArchitectureTimestepAccuracy
CIFAR-10SpikeNorm [46]ANN2SNNVGG16250091.55%
Hybrid-Train [45]Hybrid trainingVGG1620092.02%
Spike-basedBP [34]SNN trainingResNet1110090.95%
Joint A-SNN [19]SNN trainingResNet18495.45%
GLIF [60]SNN trainingResNet19294.44%
PLIF [12]SNN trainingPLIFNet893.50%
Diet-SNN [44]SNN trainingVGG16592.70%
1093.44%
ResNet20591.78%
1092.54%
RecDis-SNN [20]SNN trainingResNet19293.64%
495.53%
695.55%
Dspike [38]SNN trainingResNet20293.13%
493.66%
694.25%
STBP-tdBN [62]SNN trainingResNet19292.34%
492.92%
693.16%
TET [7]SNN trainingResNet19294.16%
494.44%
694.50%
Real Spike [21]SNN trainingResNet19295.31%
495.51%
696.10%
InfLoR-SNN [16]SNN trainingResNet20593.01%
1093.65%
MPBNSNN trainingResNet19196.06%±0.10
296.47%±0.08
ResNet20192.22%±0.11
293.54%±0.09
494.28%±0.07
VGG16293.96%±0.09
494.44%±0.08
+ +ResNet19 [62], and ResNet34 [11] on both static datasets including CIFAR-10 [32], CIFAR-100 [32], and ImageNet [6], and one neuromorphic dataset, CIFAR10-DVS [35]. The specific introduction for these datasets has been detailed in many recent works [62, 44, 21, 38]. Here, we mainly introduce these hyper-parameters and data preprocessing in detail. We used the widely adopted LIF neuron in our SNN models as other works about direct training methods [44, 46]. These hyper-parameters for LIF neuron about the initial firing threshold $V_{\mathrm{th}}$ and the membrane potential decaying constant $\tau_{\mathrm{decay}}$ are 0.5 and 0.25 respectively. For static image datasets, since encoding the 8-bit RGB images into 1-bit spikes will lose too much information, we use an ANN-like convolutional layer and a LIF layer to encode the + +images to spikes for all the rest of the layers, as in recent works [62, 44, 21, 38]. + +# 5.1. Comparison with SoTA Methods + +CIFAR-10. On CIFAR-10, we trained our SNN model using the SGD optimizer with 0.9 momentum. The initial learning rate is 0.1 and decays to 0 in cosine form. The total training time is 400 epochs. To fairly compare with these recent SoTA methods [38, 20, 16], we also adopt data normalization, random horizontal flipping, cropping, and cutout [8] for data augmentation. We run three times for each experiment to report the "mean ± std" in Tab. 2. It can be seen that our models can outperform other methods over all these chosen widely adopted architectures with + +Table 3: Comparison with SoTA methods on CIFAR-100. + +
DatasetMethodTypeArchitectureTimestepAccuracy
CIFAR-100SpikeNorm [46]ANN2SNNResNet20250064.09%
RMP [23]ANN2SNNResNet20204867.82%
Hybrid-Train [45]Hybrid trainingVGG1112567.90%
IM-Loss [15]SNN trainingVGG16570.18%
Joint A-SNN [19]SNN trainingResNet18477.39%
ResNet34479.76%
Dspike [38]SNN trainingResNet20271.68%
473.35%
674.24%
TET [7]SNN trainingResNet19272.87%
474.47%
674.72%
RecDis-SNN [20]SNN trainingResNet19474.10%
VGG16569.88%
InfLoR-SNN [16]SNN trainingResNet20571.19%
VGG16571.56%
Real Spike [21]SNN trainingResNet20566.60%
VGG16570.62%
GLIF [60]SNN trainingResNet19275.48%
477.05%
TEBN [10]SNN trainingResNet19275.86%
476.13%
676.41%
MPBNSNN trainingVGG16474.74%±0.11
ResNet19178.71%±0.10
279.51%±0.07
ResNet20270.79%±0.08
472.30%±0.08
+ +Table 4: Comparison with SoTA methods on ImageNet. + +
DatasetMethodTypeArchitectureTimestepAccuracy
ImageNetSTBP-tdBN [62]SNN trainingResNet34663.72%
TET [7]SNN trainingResNet34664.79%
MS-ResNet [27]SNN trainingResNet18663.10%
OTT [54]SNN trainingResNet34663.10%
Real Spike [21]SNN trainingResNet18463.68%
SEW ResNet [11]SNN trainingResNet18463.18%
ResNet34467.04%
MPBNSNN trainingResNet18463.14%±0.08
ResNet34464.71%±0.09
+ +fewer time steps. For example, The accuracy of spiking ResNet19 trained with MPBN with only 1 time step can be up to $96.06\%$ , while the Real Spike [21] needs 6 time steps to reach a comparable result and the RecDis-SNN [61] even still underperforms $0.51\%$ with 6 time steps. This superiority can also be observed in the results regarding the spiking + +ResNet20 and VGG16. + +CIFAR-100. For CIFAR-100, we adopted the same settings as in CIFAR-10. The proposed MPBN also performs well on CIFAR-100. It can be seen that our method gets the best accuracy over all these networks even with fewer time steps. For instants, the ResNet19 trained with MPBN + +Table 5: Comparison with SoTA methods on CIFAR10-DVS. + +
DatasetMethodTypeArchitectureTimestepAccuracy
CIFAR10-DVSRollout [33]RolloutDenseNet1066.80%
LIAF-Net [53]Conv3DLIAF-Net1071.70%
LIAF-Net [53]LIAFLIAF-Net1070.40%
STBP-tdBN [62]SNN trainingResNet191067.80%
RecDis-SNN [20]SNN trainingResNet191072.42%
Real Spike [21]SNN trainingResNet191072.85%
ResNet201078.00%
MPBNSNN trainingResNet191074.40%±0.20
ResNet201078.70%±0.10
+ +can achieve $78.71\%$ top-1 accuracy with only 1 time step, which outperforms other SoTA methods such as TET, GLIF, TEBN, and RecDis-SNN even with 4 or 6 time steps about $1.66\% -3.99\%$ . + +ImageNet. On ImageNet, we used standard data normalization, random horizontal flipping, and cropping for data augmentation and trained the networks for 320 epochs as in [11]. The optimizer setting also keeps the same with CIFAR datasets. The results for ImageNet are presented in Tab. 4. It can be seen that the accuracy of our method is better than that of these recent SoTA methods, only relatively smaller compared with SEW ResNet [11] for spiking ResNet34. However, SEW ResNet is not a typical SNN model. It adopts the activation before addition form-based ResNet and its blocks will fire positive integer spikes. In this way, the event-driven and multiplication-addition transform advantages of SNNs will be lost. While we adopt the original ResNet, which fires standard binary spikes. + +CIFAR10-DVS. We also adopted the neuromorphic dataset, CIFAR10-DVS in the paper to verify the effectiveness of the MPBN. We also split the dataset into 9K training images and 1K test images, and resize them to $48 \times 48$ for data augmentation as in [51, 21]. The learning rate is 0.01 and other settings are the same as CIFAR-10. It can be seen that the MPBN also shows superiority in this dataset. + +# 5.2. Extension of the MPBN + +In CNNs, the most widely used BN is channelwised. This is because element-wised BNs are very time-consuming and can not be folded into weights, otherwise, the channel-wised weight-sharing mechanism will be destroyed. However, the MPBN adopts the firing thresholdfolded manner and the firing threshold need not keep the same along the channels, therefore, MPBN can use the element-wised form freely. In this way, $V_{\mathrm{th}}$ will be transformed to element-wised ones as follows, + +$$ +(\tilde {\boldsymbol {V}} _ {\mathrm {t h}}) _ {i, j, k} = \frac {(V _ {\mathrm {t h}} - \beta_ {i , j , k}) \sqrt {\sigma_ {i , j , k} ^ {2}}}{\boldsymbol {\lambda} _ {i , j , k}} + \boldsymbol {\mu} _ {i, j, k}, \tag {13} +$$ + +Table 6: Comparison with learnable firing threshold methods. + +
DatasetMethodTime stepAccuracy
CIFAR-10channel-wised494.28%
element-wised494.42%
CIFAR-100channel-wised472.30%
element-wised472.49%
+ +where $(\tilde{V}_{\mathrm{th}})_{i,j,k}$ is the transformed firing threshold of the neuron comes from $i$ -th channel in the spatial position $(j,k)$ . To investigate the performance of the element-wised MPBN, here we also provide a comparison of the vanilla MPBN and its extension. The results of top-1 accuracy of the spiking ResNet20 with 4 time steps on CIFAR datasets are shown in Tab. 6. Though the two versions all perform well, the element-wised MPBN is relatively better than the channel-wised MPBN. This may be because element-wised MPBN can learn more firing threshold values, which means a richer representation ability for SNNs. + +# 6. Conclusion + +In the paper, we advocated adding the MPBN before the firing function to regulate the disturbed data flow again. We also provided a training-inference-decoupled reparameterization technique to fold the trained MPBN into the firing threshold to eliminate the extra time burden induced by MPBN in the inference time. Furthermore, the channel-wised and element-wised MPBN in different granularities were explored. Extensive experiments verified that the proposed MPBN can consistently achieve good performance. + +# Acknowledgment + +This work is supported by grants from the National Natural Science Foundation of China under contracts No.12202412 and No.12202413. + +# References + +[1] Filipp Akopyan, Jun Sawada, Andrew Cassidy, Rodrigo Alvarez-Icaza, John Arthur, Paul Merolla, Nabil Imam, Yutaka Nakamura, Pallab Datta, Gi-Joon Nam, Brian Taba, Michael Beakes, Bernard Brezzo, Jente Kuang, Rajit Manohar, W.P. Risk, Bryan Jackson, and Dharmendra Modha. Truenorth: Design and tool flow of a 65 mw 1 million neuron programmable neurosynaptic chip. Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on, 34:1537-1557, 10 2015. 1 +[2] Jimmy Lei Ba, Jamie Ryan Kiros, and Geoffrey E Hinton. Layer normalization. arXiv preprint arXiv:1607.06450, 2016. 2 +[3] G. Bellec, D. Salaj, A. Subramoney, R. Legenstein, and W. Maass. Long short-term memory and learning-to-learn in networks of spiking neurons, 2018. 4 +[4] Xiang Cheng, Yunzhe Hao, Jiaming Xu, and Bo Xu. Lisnn: Improving spiking neural networks with lateral interactions for robust object recognition. pages 1519-1525, 07 2020. 4 +[5] Mike Davies, Narayan Srinivasa, Tsung-Han Lin, Gautham Chinya, Andrew Lines, Andreas Wild, Hong Wang, and Deepak Mathaikutty. Loihi: A neuromorphic manycore processor with on-chip learning. IEEE Micro, 38:82 - 99, 01 2018. 1 +[6] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Fei-Fei Li. Imagenet: a large-scale hierarchical image database. pages 248-255, 06 2009. 6 +[7] Shikuang Deng, Yuhang Li, Shanghang Zhang, and Shi Gu. Temporal efficient training of spiking neural network via gradient re-weighting. In International Conference on Learning Representations, 2022. 6, 7 +[8] Terrance DeVries and Graham W. Taylor. Improved regularization of convolutional neural networks with cutout, 2017. 6 +[9] Travis DeWolf. Spiking neural networks take control. Science Robotics, 6(58):eabk3268, 2021. 1 +[10] Chaoteng Duan, Jianhao Ding, Shiyan Chen, Zhaofei Yu, and Tiejun Huang. Temporal effective batch normalization in spiking neural networks. In Alice H. Oh, Alekh Agarwal, Danielle Belgrave, and Kyunghyun Cho, editors, Advances in Neural Information Processing Systems, 2022. 1, 3, 7 +[11] Wei Fang, Zhaofei Yu, Yanqi Chen, Tiejun Huang, and Yonghong Tian. Deep residual learning in spiking neural networks. 2021. 2, 5, 6, 7, 8 +[12] Wei Fang, Zhaofei yu, Yanqi Chen, Timothee Masquelier, Tiejun Huang, and Yonghong Tian. Incorporating learnable membrane time constant to enhance learning of spiking neural networks. 08 2021. 1, 3, 6 +[13] Samanwoy Ghosh-Dastidar and Hojjat Adeli. Spiking neural networks. Int. J. Neural Syst., 19:295-308, 08 2009. 1 +[14] Yufei Guo and Yuanpei Chen. Neuroclip: Neuromorphic data understanding by clip and snn. arXiv preprint arXiv:2306.12073, 2023. 1 +[15] Yufei Guo, Yuanpei Chen, Liwen Zhang, Xiaode Liu, Yinglei Wang, Xuhui Huang, and Zhe Ma. IM-loss: Information maximization loss for spiking neural networks. In Alice H. + +Oh, Alekh Agarwal, Danielle Belgrave, and Kyunghyun Cho, editors, Advances in Neural Information Processing Systems, 2022. 7 +[16] Yufei Guo, Yuanpei Chen, Liwen Zhang, YingLei Wang, Xiaode Liu, Xinyi Tong, Yuanyuan Ou, Xuhui Huang, and Zhe Ma. Reducing information loss for spiking neural networks. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XI, pages 36-52. Springer, 2022. 6, 7 +[17] Yufei Guo, Xuhui Huang, and Zhe Ma. Direct learning-based deep spiking neural networks: a review. Frontiers in Neuroscience, 17:1209795, 2023. 1, 2 +[18] Yufei Guo, Xiaode Liu, Yuanpei Chen, Liwen Zhang, Wei-hang Peng, Yuhan Zhang, Xuhui Huang, and Zhe Ma. Rmp-loss: Regularizing membrane potential distribution for spiking neural networks. arXiv preprint arXiv:2308.06787, 2023.2 +[19] Yufei Guo, Weihang Peng, Yuanpei Chen, Liwen Zhang, Xiaode Liu, Xuhui Huang, and Zhe Ma. Joint a-snn: Joint training of artificial and spiking neural networks via self-distillation and weight factorization. Pattern Recognition, page 109639, 2023. 1, 2, 6, 7 +[20] Yufei Guo, Xinyi Tong, Yuanpei Chen, Liwen Zhang, Xiaode Liu, Zhe Ma, and Xuhui Huang. Recdis-snn: Rectifying membrane potential distribution for directly training spiking neural networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 326-335, June 2022. 2, 3, 5, 6, 7, 8 +[21] Yufei Guo, Liwen Zhang, Yuanpei Chen, Xinyi Tong, Xiaode Liu, YingLei Wang, Xuhui Huang, and Zhe Ma. Real spike: Learning real-valued spikes for spiking neural networks. In European Conference on Computer Vision, pages 52-68. Springer, 2022. 1, 3, 4, 6, 7, 8 +[22] Bing Han and Kaushik Roy. Deep spiking neural network: Energy efficiency through time based coding. In ECCV, pages 388-404. Springer, 2020. 2 +[23] Bing Han, Gopalakrishnan Srinivasan, and Kaushik Roy. Rmp-snn: Residual membrane potential neuron for enabling deeper high-accuracy and low-latency spiking neural network. pages 13555–13564, 06 2020. 7 +[24] Yunzhe Hao, Xuhui Huang, Meng Dong, and Bo Xu. A biologically plausible supervised learning method for spiking neural networks using the symmetric stdp rule. Neural Networks, 121, 09 2019. 2 +[25] Zecheng Hao, Tong Bu, Jianhao Ding, Tiejun Huang, and Zhaofei Yu. Reducing ann-snn conversion error through residual membrane potential, 2023. 2 +[26] Zecheng Hao, Jianhao Ding, Tong Bu, Tiejun Huang, and Zhaofei Yu. Bridging the gap between anns and snns by calibrating offset spikes, 2023. 2 +[27] Yifan Hu, Yujie Wu, Lei Deng, and Guoqi Li. Advancing residual learning towards powerful deep spiking neural networks. arXiv preprint arXiv:2112.08954, 2021. 7 +[28] Shin-ichi Ikegawa, Ryuji Saiin, Yoshihide Sawada, and Naotake Natori. Rethinking the role of normalization and residual blocks for spiking neural networks. Sensors, 22(8), 2022. 1, 3 + +[29] Sergey Ioffe and Christian Szegedy. Batch normalization: Accelerating deep network training by reducing internal covariate shift. In International conference on machine learning, pages 448-456. PMLR, 2015. 2 +[30] Seijoon Kim, Seongsik Park, Byunggook Na, and Sungroh Yoon. Spiking-yolo: spiking neural network for energy-efficient object detection. In Proceedings of the AAAI conference on artificial intelligence, volume 34, pages 11270-11277, 2020. 1 +[31] Y. Kim and P. Panda. Revisiting batch normalization for training low-latency deep spiking neural networks from scratch, 2020. 1, 3 +[32] Alex Krizhevsky, Vinod Nair, and Geoffrey Hinton. Cifar-10 (canadian institute for advanced research). 6 +[33] Alexander Kugele, Thomas Pfeil, Michael Pfeiffer, and Elisabetta Chicca. Efficient processing of spatio-temporal data streams with spiking neural networks. Frontiers in Neuroscience, 14:439, 05 2020. 8 +[34] Chankyu Lee, Syed Sarwar, Priyadarshini Panda, Gopalakrishnan Srinivasan, and Kaushik Roy. Enabling spike-based backpropagation for training deep neural network architectures. Frontiers in Neuroscience, 14:119, 02 2020. 6 +[35] Hongmin Li. Cifar10-dvs: An event-stream dataset for object classification. Frontiers in Neuroscience, 11, 05 2017. 6 +[36] Hao Li, Zheng Xu, Gavin Taylor, Christoph Studer, and Tom Goldstein. Visualizing the loss landscape of neural nets. Advances in neural information processing systems, 31, 2018. 5 +[37] Yuhang Li, Shikuang Deng, Xin Dong, and et al. A free lunch from ann: Towards efficient, accurate spiking neural networks calibration. In ICML, 2021. 2 +[38] Yuhang Li, Yufei Guo, Shanghang Zhang, Shikuang Deng, Yongqing Hai, and Shi Gu. Differentiable spike: Rethinking gradient-descent for training spiking neural networks. Advances in Neural Information Processing Systems, 34, 2021. 2, 4, 6, 7 +[39] S. A. Lobov and et al. Spatial properties of stdp in a spiking neural network enable controlling a mobile robot. Frontiers in Neuroscience, 2020. 2 +[40] Ping Luo, Jiamin Ren, Zhanglin Peng, Ruimao Zhang, and Jingyu Li. Differentiable learning-to-normalize via switchable normalization, 2019. 2 +[41] Mitchell A Nahmias, Bhavin J Shastri, Alexander N Tait, and Paul R Prucnal. A leaky integrate-and-fire laser neuron for ultrafast cognitive computing. IEEE journal of selected topics in quantum electronics, 19(5):1-12, 2013. 3 +[42] Jing Pei, Lei Deng, Sen Song, Mingguo Zhao, Youhui Zhang, Shuang Wu, Guanrui Wang, Zhe Zou, Zhenzhi Wu, Wei He, Feng Chen, Ning Deng, Si Wu, Yu Wang, Yujie Wu, Zheyu Yang, Cheng Ma, Guoqi Li, Wentao Han, and L.P. Shi. Towards artificial general intelligence with hybrid tianjic chip architecture. Nature, 572:106, 08 2019. 1 +[43] Peter, U., Diehl, Matthew, and Cook. Unsupervised learning of digit recognition using spike-timing-dependent plasticity. Frontiers in Computational Neuroscience, 9:99, 2015. 2 + +[44] Nitin Rathi and Kaushik Roy. DIET-SNN: direct input encoding with leakage and threshold optimization in deep spiking neural networks. CoRR, abs/2008.03658, 2020. 5, 6 +[45] Nitin Rathi, Gopalakrishnan Srinivasan, Priyadarshini Panda, and Kaushik Roy. Enabling deep spiking neural networks with hybrid conversion and spike timing dependent backpropagation. 05 2020. 6, 7 +[46] Abhronil Sengupta, Yuting Ye, Robert Wang, Chiao Liu, and Kaushik Roy. Going deeper in spiking neural networks: Vgg and residual architectures. Frontiers in Neuroscience, 13, 02 2018. 2, 5, 6, 7 +[47] Jiangrong Shen, Qi Xu, Jian K Liu, Yueming Wang, Gang Pan, and Huajin Tang. Esl-snns: An evolutionary structure learning strategy for spiking neural networks. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 37, pages 86-93, 2023. 1 +[48] Dmitry Ulyanov, Andrea Vedaldi, and Victor Lempitsky. Instance normalization: The missing ingredient for fast stylization, 2017. 2 +[49] Siqi Wang, Tee Hiang Cheng, and Meng-Hiot Lim. LTMD: Learning improvement of spiking neural networks with learnable thresholding neurons and moderate dropout. In Alice H. Oh, Alekh Agarwal, Danielle Belgrave, and Kyunghyun Cho, editors, Advances in Neural Information Processing Systems, 2022. 4 +[50] Yujie Wu, Lei Deng, and et al. Spatio-temporal backpropagation for training high-performance spiking neural networks. Frontiers in neuroscience, 2018. 2 +[51] Yujie Wu, Lei Deng, Guoqi Li, Jun Zhu, Yuan Xie, and L.P. Shi. Direct training for spiking neural networks: Faster, larger, better. Proceedings of the AAAI Conference on Artificial Intelligence, 33:1311-1318, 07 2019. 1, 2, 4, 8 +[52] Yuxin Wu and Kaiming He. Group normalization. In Proceedings of the European conference on computer vision (ECCV), pages 3-19, 2018. 2 +[53] Zhenzhi Wu, Hehui Zhang, Yihan Lin, Guoqi Li, Meng Wang, and Ye Tang. Liaf-net: Leaky integrate and analog fire network for lightweight and efficient spatiotemporal information processing. IEEE Transactions on Neural Networks and Learning Systems, 33(11):6249-6262, 2022. 8 +[54] Mingqing Xiao, Qingyan Meng, Zongpeng Zhang, Di He, and Zhouchen Lin. Online training through time for spiking neural networks. arXiv preprint arXiv:2210.04195, 2022. 7 +[55] Rong Xiao, Yu Wan, Baosong Yang, Haibo Zhang, Huajin Tang, Derek F Wong, and Boxing Chen. Towards energy-preserving natural language understanding with spiking neural networks. IEEE/ACM Transactions on Audio, Speech, and Language Processing, 31:439-447, 2022. 1 +[56] Qi Xu, Yaxin Li, Xuanye Fang, Jiangrong Shen, Jian K Liu, Huajin Tang, and Gang Pan. Biologically inspired structure learning with reverse knowledge distillation for spiking neural networks. arXiv preprint arXiv:2304.09500, 2023. 1 +[57] Qi Xu, Yaxin Li, Jiangrong Shen, Jian K Liu, Huajin Tang, and Gang Pan. Constructing deep spiking neural networks from artificial neural networks with knowledge distillation. arXiv preprint arXiv:2304.05627, 2023. 1 +[58] Qi Xu, Yaxin Li, Jiangrong Shen, Pingping Zhang, Jian K Liu, Huajin Tang, and Gang Pan. Hierarchical spiking-based + +model for efficient image classification with enhanced feature extraction and encoding. IEEE Transactions on Neural Networks and Learning Systems, 2022. 1 +[59] Qi Xu, Jiangrong Shen, Xuming Ran, Huajin Tang, Gang Pan, and Jian K Liu. Robust transcoding sensory information with neural spikes. IEEE Transactions on Neural Networks and Learning Systems, 33(5):1935-1946, 2021. 1 +[60] Xingting Yao, Fanrong Li, Zitao Mo, and Jian Cheng. Glif: A unified gated leaky integrate-and-fire neuron for spiking neural networks. arXiv preprint arXiv:2210.13768, 2022. 6, 7 +[61] Wenrui Zhang and Peng Li. Temporal spike sequence learning via backpropagation for deep spiking neural networks. 02 2020. 7 +[62] Hanle Zheng, Yujie Wu, Lei Deng, Yifan Hu, and Guoqi Li. Going deeper with directly-trained larger spiking neural networks. 10 2020. 1, 3, 6, 7, 8 \ No newline at end of file diff --git a/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/images.zip b/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..24bce6188341537a3bac9e5a5a94429a783a32c9 --- /dev/null +++ b/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:9819fd51e5fe8d02ce9f6d7885a4805e768df902820cd1e6108c83c39a343b55 +size 553989 diff --git a/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/layout.json b/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..e90d37b6a12d547068456146b53634f69eacc7ac --- /dev/null +++ b/2023/Membrane Potential Batch Normalization for Spiking Neural Networks/layout.json @@ -0,0 +1,9292 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 76, + 103, + 518, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 76, + 103, + 518, + 121 + ], + "spans": [ + { + "bbox": [ + 76, + 103, + 518, + 121 + ], + "type": "text", + "content": "Membrane Potential Batch Normalization for Spiking Neural Networks" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 83, + 143, + 511, + 200 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 83, + 143, + 511, + 200 + ], + "spans": [ + { + "bbox": [ + 83, + 143, + 511, + 200 + ], + "type": "text", + "content": "Yufei Guo,\\* Yuhan Zhang,\\* Yuanpei Chen, Weihang Peng, Xiaode Liu, Liwen Zhang, Xuhui Huang, Zhe Ma\\* Intelligent Science & Technology Academy of CASIC, China Scientific Research Laboratory of Aerospace Intelligent Systems and Technology, China" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 227, + 192, + 239 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 227, + 192, + 239 + ], + "spans": [ + { + "bbox": [ + 143, + 227, + 192, + 239 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 253, + 289, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 253, + 289, + 529 + ], + "spans": [ + { + "bbox": [ + 46, + 253, + 289, + 529 + ], + "type": "text", + "content": "As one of the energy-efficient alternatives of conventional neural networks (CNNs), spiking neural networks (SNNs) have gained more and more interest recently. To train the deep models, some effective batch normalization (BN) techniques are proposed in SNNs. All these BNs are suggested to be used after the convolution layer as usually doing in CNNs. However, the spiking neuron is much more complex with the spatio-temporal dynamics. The regulated data flow after the BN layer will be disturbed again by the membrane potential updating operation before the firing function, i.e., the nonlinear activation. Therefore, we advocate adding another BN layer before the firing function to normalize the membrane potential again, called MPBN. To eliminate the induced time cost of MPBN, we also propose a training-inference-decoupled re-parameterization technique to fold the trained MPBN into the firing threshold. With the re-parameterization technique, the MPBN will not introduce any extra time burden in the inference. Furthermore, the MPBN can also adopt the element-wised form, while these BNs after the convolution layer can only use the channel-wised form. Experimental results show that the proposed MPBN performs well on both popular non-spiking static and neuromorphic datasets." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 553, + 128, + 566 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 553, + 128, + 566 + ], + "spans": [ + { + "bbox": [ + 47, + 553, + 128, + 566 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 574, + 287, + 682 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 574, + 287, + 682 + ], + "spans": [ + { + "bbox": [ + 46, + 574, + 287, + 682 + ], + "type": "text", + "content": "Emerged as a biology-inspired method, spiking neural networks (SNNs) have received much attention in artificial intelligence and neuroscience recently [17, 13, 57, 56, 47, 58, 59]. SNNs deal with binary event-driven spikes as their activations and therefore the multiplications of activations and weights can be substituted for additions or only keeping silent. Benefitting from such a computation paradigm, SNNs derive extreme energy efficiency and run efficiently when implemented on neuromorphic hardware [1, 42, 5]." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 228, + 547, + 563 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 228, + 547, + 563 + ], + "spans": [ + { + "bbox": [ + 306, + 228, + 547, + 563 + ], + "type": "text", + "content": "Despite the SNN has achieved great success in diverse fields including pattern recognition [12, 21, 19, 14], object detection [30], language processing [55], robotics [9], and so on, its development is deeply inspired by the experience of convolutional neural networks (CNNs) in many aspects. However, the spiking neuron model along with the rich spatio-temporal dynamic makes SNNs much different from CNNs, and directly transferring some experience of CNNs to SNNs without any modifications may be not a good idea. As one of the famous techniques in CNNs, the batch normalization(BN) technique shows great advantages. It can reduce the gradient exploding/vanishing problem, flatten the loss landscape, and reduce the internal covariate shift, thus being widely used in CNNs. There are also some works trying to apply normalization approaches in the SNN field to help model convergence. For example, inspired by BN in CNNs, NeuNorm [51] was proposed to normalize the data along the channel dimension. Considering that the temporal dimension is also important in SNNs, threshold-dependent batch normalization (tdBN) [62] then extended the scope of BN to the additional temporal dimension. Subsequently, to better depict the differences of data flow distributions in different time dimensions, the temporal batch normalization through time (BNTT) [31], postsynaptic potential normalization (PSP-BN) [28], and temporal effective batch normalization (TEBN) [10] that regulate the data flows with multiple BNs on different time steps were proposed." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 570, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 547, + 715 + ], + "type": "text", + "content": "However, all these BNs proposed in SNNs are advised to be used after convolution layers as usually doing in CNNs. This ignores the fact that the nonlinear transformation in the SNN spiking neuron is much more complex than that of the ReLU neuron. In the spiking neuron, the data flow after the convolution layer will be first injected into the residual membrane potential (MP) coming from the previous time step to generate a new MP at the current time step. And then the neuron will fire a spike or keep silent still based on whether or not the new MP is up to the firing threshold. Obviously, though the data flow has been normalized by the BN after the convolution layer, it will be" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 693, + 209, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 693, + 209, + 713 + ], + "spans": [ + { + "bbox": [ + 58, + 693, + 209, + 713 + ], + "type": "text", + "content": "*Equal contribution. \n†Corresponding author, mazhe_thu@163.com." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "19420" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 69, + 71, + 267, + 235 + ], + "blocks": [ + { + "bbox": [ + 69, + 71, + 267, + 235 + ], + "lines": [ + { + "bbox": [ + 69, + 71, + 267, + 235 + ], + "spans": [ + { + "bbox": [ + 69, + 71, + 267, + 235 + ], + "type": "image", + "image_path": "753c39a704f8c0eb5fca69152ad5cf5c19d1c3127871e3cc9636e26d81ea5f28.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 243, + 289, + 316 + ], + "lines": [ + { + "bbox": [ + 46, + 243, + 289, + 316 + ], + "spans": [ + { + "bbox": [ + 46, + 243, + 289, + 316 + ], + "type": "text", + "content": "Figure 1: The difference between our SNN with MPBN and the vanilla SNN. We add another BN layer after membrane potential updating (MPU) operation in the training. The MPBN can be folded into the firing threshold and then the homogenous firing threshold will be transformed into different ones." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 334, + 288, + 501 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 334, + 288, + 501 + ], + "spans": [ + { + "bbox": [ + 46, + 334, + 288, + 501 + ], + "type": "text", + "content": "disturbed again by the residual MP in the membrane potential updating process. Therefore, we advocate also adding a BN layer after MP updating to regulate the data flow once again, called MPBN. Furthermore, we also propose a training-inference-decoupled re-parameterization technique in SNNs to fold the trained MPBN into the firing threshold. Hence, the MPBN will not induce any extra burden in the inference but a trivial burden in the training. The MPBN can be extended to channel-wised MPBN and element-wised MPBN further, which is very different from that of CNNs where only channel-wised normalization can be folded into weights. The difference between our SNN with MPBN and the vanilla SNN is illustrated in Fig. 1. Our main contributions are as follows:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 58, + 509, + 288, + 714 + ], + "type": "list", + "angle": 0, + "index": 6, + "blocks": [ + { + "bbox": [ + 58, + 509, + 287, + 582 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 509, + 287, + 582 + ], + "spans": [ + { + "bbox": [ + 58, + 509, + 287, + 582 + ], + "type": "text", + "content": "- We propose to add another BN layer after the membrane potential updating operation named MPBN to handle the data flow disturbance in the spiking neuron. The experiment shows that MPBN can flatten the loss landscape further, thus benefiting model convergence and task accuracy." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 58, + 586, + 287, + 684 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 586, + 287, + 684 + ], + "spans": [ + { + "bbox": [ + 58, + 586, + 287, + 684 + ], + "type": "text", + "content": "- We also propose a re-parameterization method to decouple the training-time SNN and the inference-time SNN. In specific, we propose a method to fold the trained MPBN parameter into the firing threshold. Therefore, MPBN can be seen as only training auxiliary manner free from burdens in the inference-time. This re-parameterization method is suitable for both channel-wised MPBN and element-wised MPBN." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 58, + 689, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 689, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 58, + 689, + 288, + 714 + ], + "type": "text", + "content": "- Extensive experiment results show that the SNN trained with the MPBN is highly effective compared" + } + ] + } + ], + "index": 5 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 325, + 72, + 547, + 121 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 325, + 72, + 547, + 121 + ], + "spans": [ + { + "bbox": [ + 325, + 72, + 547, + 121 + ], + "type": "text", + "content": "with other state-of-the-art SNN models on both static and dynamic datasets, e.g., " + }, + { + "bbox": [ + 325, + 72, + 547, + 121 + ], + "type": "inline_equation", + "content": "96.47\\%" + }, + { + "bbox": [ + 325, + 72, + 547, + 121 + ], + "type": "text", + "content": " top-1 accuracy and " + }, + { + "bbox": [ + 325, + 72, + 547, + 121 + ], + "type": "inline_equation", + "content": "79.51\\%" + }, + { + "bbox": [ + 325, + 72, + 547, + 121 + ], + "type": "text", + "content": " top-1 accuracy are achieved on the CIFAR-10 and CIFAR-100 with only 2 time steps." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 133, + 392, + 145 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 133, + 392, + 145 + ], + "spans": [ + { + "bbox": [ + 306, + 133, + 392, + 145 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 152, + 505, + 166 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 152, + 505, + 166 + ], + "spans": [ + { + "bbox": [ + 306, + 152, + 505, + 166 + ], + "type": "text", + "content": "2.1. Learning of Spiking Neural Networks" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 171, + 547, + 472 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 171, + 547, + 472 + ], + "spans": [ + { + "bbox": [ + 304, + 171, + 547, + 472 + ], + "type": "text", + "content": "There are three kinds of learning algorithms of SNNs, including unsupervised learning [43, 24], converting ANN to SNN (ANN2SNN) [46, 25, 26], and supervised learning [19, 38, 20]. Unsupervised learning adopts some biological mechanism to update the SNN model, i.e., the spiketiming-dependent plasticity (STDP) approach [39], thus being considered a biologically plausible method. However, STDP cannot help train large-scale networks yet, thus it is usually limited to small datasets and non-ideal performance. The ANN-SNN conversion approach [22, 37] obtains an SNN by reusing well-trained homogeneous ANN parameters and replacing the ReLU neuron with a spiking neuron. Since the ANN model is easier to train and reach high performance, the ANN-SNN conversion method provides an interesting way to generate an SNN in a short time with competitive performance. However, the converted SNN will lose the rich temporal dynamic behaviors and thus cannot handle neuromorphic datasets well. Supervised learning [11, 50, 18] adopts the surrogate gradient (SG) approach to train SNNs with error backpropagation. It can handle temporal data and provide decent performance with few time steps on the large-scale dataset, thus having received much attention recently. For a more detailed introduction, please refer to the recent SNN survey [17]. Our work falls under the supervised learning." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 479, + 529, + 491 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 479, + 529, + 491 + ], + "spans": [ + { + "bbox": [ + 306, + 479, + 529, + 491 + ], + "type": "text", + "content": "2.2. Normalization in Spiking Neural Networks" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 498, + 545, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 498, + 545, + 676 + ], + "spans": [ + { + "bbox": [ + 304, + 498, + 545, + 676 + ], + "type": "text", + "content": "The batch normalization technique was originally introduced as a kind of training auxiliary method by [29] in CNNs. It uses the weight-summed input over a mini-batch of training cases to compute a mean and variance and then uses them to regulate the summed input. This simple operation can derive many benefits. i) It reduces the internal covariate shift (ICS), thus accelerating the training of a deep neural network. ii) It makes the network insensitive to the scale of the gradients, thus a higher learning rate can be chosen to accelerate the training. iii) It makes the network suitable for more nonlinearities by preventing the network from getting stuck in the saturated modes. With these advantages, more kinds of BNs were proposed, including layer normalization [2], group normalization [52], instance normalization [48], and switchable normalization [40]." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 677, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 547, + 713 + ], + "type": "text", + "content": "There are also some works that modify and apply normalization approaches in the SNN field. For example, NeuNorm [51] also normalizes the feature map along the chan" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19421" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 346 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 346 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 346 + ], + "type": "text", + "content": "nel dimension like BN in CNNs. Recently, some methods were proposed to normalize the feature map from both the channel dimension and temporal dimension to take care of the spatio-temporal characteristics of the SNN, such as the threshold-dependent batch normalization (tdBN) [62]. It extends the scope of BN to the additional temporal dimension by adopting a 3DBN-like normalization method in CNNs. Note that, the tdBN can be folded into the weights, thus inducing no burden in the inference time. Nevertheless, NeuNorm and tdBN still use the shared parameters along the temporal dimension. Some works argued that the distributions of data in different time steps vary wildly and that using shared parameters is not a good choice. Subsequently, the temporal batch normalization through time (BNTT) [31], postsynaptic potential normalization (PSP-BN) [28], and temporal effective batch normalization (TEBN) [10] were proposed. These BNs regulate the data flow utilizing different parameters through time steps. Though these BNs with different BN parameters on different time steps can train more well-performed SNN models, their parameters can not be folded into the weights, thus will increase the computations and running time in the inference." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 348, + 289, + 456 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 348, + 289, + 456 + ], + "spans": [ + { + "bbox": [ + 46, + 348, + 289, + 456 + ], + "type": "text", + "content": "Nevertheless, all these BNs in the SNN field are advised to be used after convolution layers. However, the data flow after the convolution layer will not be presented to the firing function directly but to the membrane potential updating function first. Hence, the data flow will be disturbed again before reaching the firing function. To this end, in this paper, we add another BN after the membrane potential updating function, called the MPBN to retain normalized data flow before the firing function." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 469, + 125, + 483 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 469, + 125, + 483 + ], + "spans": [ + { + "bbox": [ + 47, + 469, + 125, + 483 + ], + "type": "text", + "content": "3. Preliminary" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 490, + 222, + 502 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 490, + 222, + 502 + ], + "spans": [ + { + "bbox": [ + 47, + 490, + 222, + 502 + ], + "type": "text", + "content": "3.1. Leaky Integrate-and-Fire Model" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 509, + 287, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 509, + 287, + 628 + ], + "spans": [ + { + "bbox": [ + 46, + 509, + 287, + 628 + ], + "type": "text", + "content": "Different from CNNs, SNNs use binary spikes to transmit information. In the paper, we use the widely used Leaky-Integrate-and-Fire (LIF) neuron model [41] to introduce the unique spatial-temporal dynamic of the spiking model. First, we introduce the notation rules used here as follows. Vectors or tensors are denoted by bold italic letters, i.e., " + }, + { + "bbox": [ + 46, + 509, + 287, + 628 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 46, + 509, + 287, + 628 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 509, + 287, + 628 + ], + "type": "inline_equation", + "content": "\\mathbf{o}" + }, + { + "bbox": [ + 46, + 509, + 287, + 628 + ], + "type": "text", + "content": " represent the input and output variables respectively. Matrices are denoted by bold capital letters. For instance, " + }, + { + "bbox": [ + 46, + 509, + 287, + 628 + ], + "type": "inline_equation", + "content": "\\mathbf{W}" + }, + { + "bbox": [ + 46, + 509, + 287, + 628 + ], + "type": "text", + "content": " is the weight matrix. The constant is denoted by small letters." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 59, + 630, + 242, + 642 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 630, + 242, + 642 + ], + "spans": [ + { + "bbox": [ + 59, + 630, + 242, + 642 + ], + "type": "text", + "content": "In LIF, the membrane potential is updated by" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 55, + 651, + 287, + 677 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 651, + 287, + 677 + ], + "spans": [ + { + "bbox": [ + 55, + 651, + 287, + 677 + ], + "type": "interline_equation", + "content": "\\boldsymbol {u} ^ {(t + 1), \\text {p r e}} = \\tau \\boldsymbol {u} ^ {(t)} + \\boldsymbol {c} ^ {(t + 1)}, \\text {w h e r e} \\boldsymbol {c} ^ {(t + 1)} = \\mathbf {W} \\boldsymbol {x} ^ {(t + 1)}, \\tag {1}", + "image_path": "cee75590954ae4ca747aafff3d249a1ae81fa176a448fa669ca3a60f295b4614.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\pmb{u}" + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": " represents the membrane potential and " + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\pmb{u}^{(t + 1),\\mathrm{pre}}" + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": " is the updated membrane potential at time step " + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "inline_equation", + "content": "t + 1" + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\pmb{c}^{(t + 1)}" + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": " is the pre-synaptic input at time step " + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "inline_equation", + "content": "t + 1" + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": ", which is charged" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "content": "by weight-summed input spikes " + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "inline_equation", + "content": "\\pmb{x}^{(t + 1)}" + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "content": " is a constant within (0, 1), which controls the leakage of the membrane potential. Then, when the updated membrane potential " + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "inline_equation", + "content": "\\pmb{u}^{(t + 1),\\mathrm{pre}}" + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "content": " is up to the firing threshold " + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{th}}" + }, + { + "bbox": [ + 304, + 72, + 545, + 133 + ], + "type": "text", + "content": ", the LIF spiking neuron will fire a spike as below," + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 353, + 142, + 545, + 174 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 353, + 142, + 545, + 174 + ], + "spans": [ + { + "bbox": [ + 353, + 142, + 545, + 174 + ], + "type": "interline_equation", + "content": "\\boldsymbol {o} ^ {(t + 1)} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f} \\boldsymbol {u} ^ {(t + 1), \\text {p r e}} > V _ {\\text {t h}} \\\\ 0 & \\text {o t h e r w i s e} \\end{array} , \\right. \\tag {2}", + "image_path": "b945f07ca1c763b26b5f0fbe32d5a5681cad8885780f24daee6efdff21955470.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 356, + 176, + 498, + 191 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 356, + 176, + 498, + 191 + ], + "spans": [ + { + "bbox": [ + 356, + 176, + 498, + 191 + ], + "type": "interline_equation", + "content": "\\boldsymbol {u} ^ {(t + 1)} = \\boldsymbol {u} ^ {(t + 1), \\text {p r e}} \\cdot (1 - \\boldsymbol {o} ^ {(t + 1)}).", + "image_path": "e8687bead1d069ff32d7a53c9f8264329e8ca668b22fd613829f0214208a6243.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 202, + 545, + 262 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 202, + 545, + 262 + ], + "spans": [ + { + "bbox": [ + 304, + 202, + 545, + 262 + ], + "type": "text", + "content": "After firing, the spike output " + }, + { + "bbox": [ + 304, + 202, + 545, + 262 + ], + "type": "inline_equation", + "content": "\\pmb{o}^{(t + 1)}" + }, + { + "bbox": [ + 304, + 202, + 545, + 262 + ], + "type": "text", + "content": " at time step " + }, + { + "bbox": [ + 304, + 202, + 545, + 262 + ], + "type": "inline_equation", + "content": "t + 1" + }, + { + "bbox": [ + 304, + 202, + 545, + 262 + ], + "type": "text", + "content": " will be transmitted to the next layer and become its input. At the same time, the updated membrane potential will be reset to zero and becomes " + }, + { + "bbox": [ + 304, + 202, + 545, + 262 + ], + "type": "inline_equation", + "content": "\\pmb{u}^{(t + 1)}" + }, + { + "bbox": [ + 304, + 202, + 545, + 262 + ], + "type": "text", + "content": " to join the neuron processing at the next time step." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 264, + 545, + 359 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 264, + 545, + 359 + ], + "spans": [ + { + "bbox": [ + 304, + 264, + 545, + 359 + ], + "type": "text", + "content": "The Classifier in the SNN. In a classification model, the final output is used to compute the Softmax and predict the desired class object. In an SNN model, if we also use LIF neurons at the output layer to fire spikes and use the number of spikes to compute the probability, too much information will be lost. Therefore, we only integrate the output and do not fire them across time, as doing in recent work [20, 21, 12]." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 353, + 361, + 545, + 393 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 353, + 361, + 545, + 393 + ], + "spans": [ + { + "bbox": [ + 353, + 361, + 545, + 393 + ], + "type": "interline_equation", + "content": "\\boldsymbol {o} _ {\\text {o u t}} = \\frac {1}{T} \\sum_ {t = 1} ^ {T} \\boldsymbol {c} _ {\\text {o u t}} ^ {(t)} = \\frac {1}{T} \\sum_ {t = 1} ^ {T} \\mathbf {W} \\boldsymbol {x} ^ {(t)}. \\tag {3}", + "image_path": "0d7721449c4cf65a0a827136b2311899e1bab01c250f11d4e41eaa75b2c87756.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 399, + 545, + 424 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 399, + 545, + 424 + ], + "spans": [ + { + "bbox": [ + 304, + 399, + 545, + 424 + ], + "type": "text", + "content": "Then, the cross-entropy loss is computed based on the true label and " + }, + { + "bbox": [ + 304, + 399, + 545, + 424 + ], + "type": "inline_equation", + "content": "\\operatorname{Softmax}(\\pmb{o}_{\\mathrm{out}})" + }, + { + "bbox": [ + 304, + 399, + 545, + 424 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 434, + 468, + 445 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 434, + 468, + 445 + ], + "spans": [ + { + "bbox": [ + 306, + 434, + 468, + 445 + ], + "type": "text", + "content": "3.2. Batch Normalization in SNNs" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 453, + 545, + 537 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 453, + 545, + 537 + ], + "spans": [ + { + "bbox": [ + 304, + 453, + 545, + 537 + ], + "type": "text", + "content": "Batch normalization can effectively reduce the internal covariate shift and alleviate the gradient vanishing or explosion problem for training networks, thus having been widely used in CNNs. Fortunately, BN can also be used in SNNs. Considering a spiking neuron with input " + }, + { + "bbox": [ + 304, + 453, + 545, + 537 + ], + "type": "inline_equation", + "content": "\\pmb{c} = \\{c^{(1)}, c^{(2)}, \\dots, c^{(t)}, \\dots\\}" + }, + { + "bbox": [ + 304, + 453, + 545, + 537 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 453, + 545, + 537 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 453, + 545, + 537 + ], + "type": "text", + "content": " is the time step, BN regulate the input at each time step as follows," + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 388, + 547, + 545, + 578 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 388, + 547, + 545, + 578 + ], + "spans": [ + { + "bbox": [ + 388, + 547, + 545, + 578 + ], + "type": "interline_equation", + "content": "\\tilde {\\boldsymbol {c}} _ {i} ^ {(t)} = \\frac {\\boldsymbol {c} _ {i} ^ {(t)} - \\boldsymbol {\\mu} _ {i}}{\\sqrt {\\boldsymbol {\\sigma} _ {i} ^ {2} + \\epsilon}}, \\tag {4}", + "image_path": "88e77bd4cf5debbea048a8e5411b5e8c8aad837870063d1fc76fb1b22515ea70.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "inline_equation", + "content": "c_{i}^{(t)}" + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "text", + "content": " is the input in " + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "text", + "content": "-th channel at " + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "text", + "content": "-th time step, " + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "inline_equation", + "content": "\\mu_{i}" + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "inline_equation", + "content": "\\sigma_{i}" + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "text", + "content": " are the mean and variance of input in channel dimension, and " + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "text", + "content": " is a small constant to avoid denominator being zero. To ensure BN can represent the identity transformation, the normalized vector " + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "inline_equation", + "content": "\\tilde{c}_{i}^{(t)}" + }, + { + "bbox": [ + 304, + 589, + 545, + 665 + ], + "type": "text", + "content": " is scaled and shifted in a learning manner as follows," + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 374, + 674, + 545, + 691 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 374, + 674, + 545, + 691 + ], + "spans": [ + { + "bbox": [ + 374, + 674, + 545, + 691 + ], + "type": "interline_equation", + "content": "\\operatorname {B N} \\left(\\boldsymbol {c} _ {i} ^ {(t)}\\right) = \\boldsymbol {\\lambda} _ {i} \\tilde {\\boldsymbol {c}} _ {i} ^ {(t)} + \\boldsymbol {\\beta} _ {i}, \\tag {5}", + "image_path": "22bfe47621499b370f32fdd911fa02e93223906ed136375c04122319337c772d.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 701, + 537, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 701, + 537, + 714 + ], + "spans": [ + { + "bbox": [ + 306, + 701, + 537, + 714 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 306, + 701, + 537, + 714 + ], + "type": "inline_equation", + "content": "\\lambda_{i}" + }, + { + "bbox": [ + 306, + 701, + 537, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 701, + 537, + 714 + ], + "type": "inline_equation", + "content": "\\beta_{i}" + }, + { + "bbox": [ + 306, + 701, + 537, + 714 + ], + "type": "text", + "content": " are channel-wised learnable parameters." + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19422" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 71, + 129, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 71, + 129, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 71, + 129, + 85 + ], + "type": "text", + "content": "4. Methodology" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 91, + 289, + 199 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 91, + 289, + 199 + ], + "spans": [ + { + "bbox": [ + 46, + 91, + 289, + 199 + ], + "type": "text", + "content": "This section first introduces the specific form of membrane potential batch normalization. Then the reparameterization technique that how to fold the MPBN into " + }, + { + "bbox": [ + 46, + 91, + 289, + 199 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{th}}" + }, + { + "bbox": [ + 46, + 91, + 289, + 199 + ], + "type": "text", + "content": " will be introduced in detail. Next, some key details for training the SNN and the pseudocode for the training and inference of our SNN will be given. Finally, we will provide plenty of ablation studies and the comparison of the loss landscape of the models with or without MPBN to show the effectiveness of the proposed method." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 205, + 267, + 217 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 205, + 267, + 217 + ], + "spans": [ + { + "bbox": [ + 47, + 205, + 267, + 217 + ], + "type": "text", + "content": "4.1. Membrane Potential Batch Normalization" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 224, + 287, + 283 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 224, + 287, + 283 + ], + "spans": [ + { + "bbox": [ + 46, + 224, + 287, + 283 + ], + "type": "text", + "content": "As abovementioned, we argue that though the data flow has been normalized by the BN after the convolution layer, it will be disturbed again by the membrane potential updating operation. To better depict this, we give the vanilla form of LIF neuron with BN first as follows," + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 91, + 289, + 287, + 304 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 289, + 287, + 304 + ], + "spans": [ + { + "bbox": [ + 91, + 289, + 287, + 304 + ], + "type": "interline_equation", + "content": "\\boldsymbol {u} ^ {(t + 1), \\text {p r e}} = \\tau \\boldsymbol {u} ^ {(t)} + \\mathrm {B N} (\\mathbf {W} \\boldsymbol {x} ^ {(t + 1)}), \\tag {6}", + "image_path": "44ded41052ab22284ec0e3d56ba85e268c68c06bacf2e9a5592cdbd5900db716.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 311, + 287, + 369 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 311, + 287, + 369 + ], + "spans": [ + { + "bbox": [ + 46, + 311, + 287, + 369 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 311, + 287, + 369 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 46, + 311, + 287, + 369 + ], + "type": "text", + "content": " is 0.25 in the paper following [21, 38, 4]. To regulate the disturbed data flow once again, We further embed another BN after the membrane potential updating operation, called MPBN. The LIF neuron with MPBN can be updated as" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 100, + 369, + 287, + 384 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 100, + 369, + 287, + 384 + ], + "spans": [ + { + "bbox": [ + 100, + 369, + 287, + 384 + ], + "type": "interline_equation", + "content": "\\tilde {\\boldsymbol {u}} ^ {(t + 1), \\text {p r e}} = \\operatorname {M P B N} (\\boldsymbol {u} ^ {(t + 1), \\text {p r e}}). \\tag {7}", + "image_path": "5616402e634f81c8655ae78b7ee65d7dedbf69b4bc985f679d1e8da53df58945.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 386, + 287, + 471 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 386, + 287, + 471 + ], + "spans": [ + { + "bbox": [ + 46, + 386, + 287, + 471 + ], + "type": "text", + "content": "Obviously, " + }, + { + "bbox": [ + 46, + 386, + 287, + 471 + ], + "type": "inline_equation", + "content": "\\pmb{u}^{(t + 1),\\mathrm{pre}}" + }, + { + "bbox": [ + 46, + 386, + 287, + 471 + ], + "type": "text", + "content": " will be scaled and sifted, and some " + }, + { + "bbox": [ + 46, + 386, + 287, + 471 + ], + "type": "inline_equation", + "content": "\\pmb{u}^{(t + 1),\\mathrm{pre}}" + }, + { + "bbox": [ + 46, + 386, + 287, + 471 + ], + "type": "text", + "content": " less than " + }, + { + "bbox": [ + 46, + 386, + 287, + 471 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{th}}" + }, + { + "bbox": [ + 46, + 386, + 287, + 471 + ], + "type": "text", + "content": " may be greater than " + }, + { + "bbox": [ + 46, + 386, + 287, + 471 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{th}}" + }, + { + "bbox": [ + 46, + 386, + 287, + 471 + ], + "type": "text", + "content": " with MPBN and vice versa. This is abhorrent with the biology and MPBN will cause some extra computation burden in the inference compared with the vanilla one. To solve this problem, we also propose a training-inference-decoupled re-parameterization technique here." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 477, + 167, + 489 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 477, + 167, + 489 + ], + "spans": [ + { + "bbox": [ + 47, + 477, + 167, + 489 + ], + "type": "text", + "content": "4.2. Re-parameterization" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 59, + 495, + 264, + 508 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 495, + 264, + 508 + ], + "spans": [ + { + "bbox": [ + 59, + 495, + 264, + 508 + ], + "type": "text", + "content": "With MPBN, the firing function will be updated as" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 75, + 513, + 287, + 546 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 75, + 513, + 287, + 546 + ], + "spans": [ + { + "bbox": [ + 75, + 513, + 287, + 546 + ], + "type": "interline_equation", + "content": "\\boldsymbol {o} ^ {(t + 1)} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f M P B N} (\\boldsymbol {u} ^ {(t + 1), \\text {p r e}}) > V _ {\\text {t h}} \\\\ 0 & \\text {o t h e r w i s e} \\end{array} . \\right. \\tag {8}", + "image_path": "7a6ae7ab9ff7a9b5172c4881b679c9e3b2dbf662c38653d32ad09cc818ef7345.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 551, + 287, + 574 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 551, + 287, + 574 + ], + "spans": [ + { + "bbox": [ + 46, + 551, + 287, + 574 + ], + "type": "text", + "content": "If we unfold the MPBN, the above equation will be reorganized as" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 72, + 581, + 287, + 619 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 72, + 581, + 287, + 619 + ], + "spans": [ + { + "bbox": [ + 72, + 581, + 287, + 619 + ], + "type": "interline_equation", + "content": "\\boldsymbol {o} _ {i} ^ {(t + 1)} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f} \\lambda_ {i} \\frac {\\boldsymbol {u} _ {i} ^ {(t + 1) , \\text {p r e}} - \\boldsymbol {\\mu} _ {i}}{\\sqrt {\\sigma_ {i} ^ {2}}} + \\beta_ {i} > V _ {\\text {t h}} \\\\ 0 & \\text {o t h e r w i s e} \\end{array} . \\right. \\tag {9}", + "image_path": "4aa9b315921a86f46badabefb5037ef05b87aa982b26baea286cb37ac421e780.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 625, + 287, + 649 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 625, + 287, + 649 + ], + "spans": [ + { + "bbox": [ + 46, + 625, + 287, + 649 + ], + "type": "text", + "content": "By folding the MPBN to " + }, + { + "bbox": [ + 46, + 625, + 287, + 649 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{th}}" + }, + { + "bbox": [ + 46, + 625, + 287, + 649 + ], + "type": "text", + "content": ", the firing function will be further updated as" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 91, + 655, + 287, + 691 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 655, + 287, + 691 + ], + "spans": [ + { + "bbox": [ + 91, + 655, + 287, + 691 + ], + "type": "interline_equation", + "content": "\\boldsymbol {o} _ {i} ^ {(t + 1)} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f} \\boldsymbol {u} ^ {(t + 1), \\text {p r e}} > \\left(\\tilde {\\boldsymbol {V}} _ {\\mathrm {t h}}\\right) _ {i} \\\\ 0 & \\text {o t h e r w i s e} \\end{array} , \\right. \\tag {10}", + "image_path": "0d50c2f1f4539f689ff89f863e4b1e8ed806379691b6d84f08105e4336c9a080.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 86, + 691, + 247, + 716 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 86, + 691, + 247, + 716 + ], + "spans": [ + { + "bbox": [ + 86, + 691, + 247, + 716 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 86, + 691, + 247, + 716 + ], + "type": "inline_equation", + "content": "(\\tilde{V}_{\\mathrm{th}})_i = \\frac{(V_{\\mathrm{th}} - \\beta_i)\\sqrt{\\sigma_i^2}}{\\lambda_i} +\\pmb {\\mu}_i" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 72, + 505, + 83 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 505, + 83 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 505, + 83 + ], + "type": "text", + "content": "Algorithm 1 Training and inference of our SNN." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 86, + 347, + 97 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 86, + 347, + 97 + ], + "spans": [ + { + "bbox": [ + 306, + 86, + 347, + 97 + ], + "type": "text", + "content": "Training" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 98, + 545, + 121 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 98, + 545, + 121 + ], + "spans": [ + { + "bbox": [ + 306, + 98, + 545, + 121 + ], + "type": "text", + "content": "Input: An SNN to be trained with MPBN; training dataset; total training iteration: " + }, + { + "bbox": [ + 306, + 98, + 545, + 121 + ], + "type": "inline_equation", + "content": "I_{\\text{train}}" + }, + { + "bbox": [ + 306, + 98, + 545, + 121 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 306, + 121, + 436, + 133 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 121, + 436, + 133 + ], + "spans": [ + { + "bbox": [ + 306, + 121, + 436, + 133 + ], + "type": "text", + "content": "Output: The well-trained SNN." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 312, + 135, + 545, + 277 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 312, + 135, + 477, + 147 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 135, + 477, + 147 + ], + "spans": [ + { + "bbox": [ + 312, + 135, + 477, + 147 + ], + "type": "text", + "content": "1: for all " + }, + { + "bbox": [ + 312, + 135, + 477, + 147 + ], + "type": "inline_equation", + "content": "i = 1,2,\\ldots ,{I}_{\\text{train }}" + }, + { + "bbox": [ + 312, + 135, + 477, + 147 + ], + "type": "text", + "content": " iteration do" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 312, + 148, + 545, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 148, + 545, + 171 + ], + "spans": [ + { + "bbox": [ + 312, + 148, + 545, + 171 + ], + "type": "text", + "content": "2: Get mini-batch training data, " + }, + { + "bbox": [ + 312, + 148, + 545, + 171 + ], + "type": "inline_equation", + "content": "\\pmb{x}_{\\mathrm{in}}(i)" + }, + { + "bbox": [ + 312, + 148, + 545, + 171 + ], + "type": "text", + "content": " and class label, " + }, + { + "bbox": [ + 312, + 148, + 545, + 171 + ], + "type": "inline_equation", + "content": "\\pmb{y}(i)" + }, + { + "bbox": [ + 312, + 148, + 545, + 171 + ], + "type": "text", + "content": ";" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 312, + 171, + 545, + 194 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 171, + 545, + 194 + ], + "spans": [ + { + "bbox": [ + 312, + 171, + 545, + 194 + ], + "type": "text", + "content": "3: Feed the " + }, + { + "bbox": [ + 312, + 171, + 545, + 194 + ], + "type": "inline_equation", + "content": "\\pmb{x}_{\\mathrm{in}}(i)" + }, + { + "bbox": [ + 312, + 171, + 545, + 194 + ], + "type": "text", + "content": " into the SNN and regulate the data flow by BN and MPBN;" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 312, + 195, + 514, + 207 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 195, + 514, + 207 + ], + "spans": [ + { + "bbox": [ + 312, + 195, + 514, + 207 + ], + "type": "text", + "content": "4: Calculate the SNN output, " + }, + { + "bbox": [ + 312, + 195, + 514, + 207 + ], + "type": "inline_equation", + "content": "\\pmb{o}_{\\mathrm{out}}(i)" + }, + { + "bbox": [ + 312, + 195, + 514, + 207 + ], + "type": "text", + "content": " by Eq. 3;" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 312, + 208, + 545, + 231 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 208, + 545, + 231 + ], + "spans": [ + { + "bbox": [ + 312, + 208, + 545, + 231 + ], + "type": "text", + "content": "5: Compute classification loss " + }, + { + "bbox": [ + 312, + 208, + 545, + 231 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{CE}}" + }, + { + "bbox": [ + 312, + 208, + 545, + 231 + ], + "type": "text", + "content": " = " + }, + { + "bbox": [ + 312, + 208, + 545, + 231 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{CE}}(\\pmb{o}_{\\mathrm{out}}(i),\\pmb{y}(i));" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 312, + 232, + 504, + 243 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 232, + 504, + 243 + ], + "spans": [ + { + "bbox": [ + 312, + 232, + 504, + 243 + ], + "type": "text", + "content": "6: Calculate the gradient w.r.t. W by Eq. 11;" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 312, + 243, + 545, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 243, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 312, + 243, + 545, + 266 + ], + "type": "text", + "content": "7: Update " + }, + { + "bbox": [ + 312, + 243, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\mathbf{W}" + }, + { + "bbox": [ + 312, + 243, + 545, + 266 + ], + "type": "text", + "content": ": " + }, + { + "bbox": [ + 312, + 243, + 545, + 266 + ], + "type": "inline_equation", + "content": "(\\mathbf{W} \\leftarrow \\mathbf{W} - \\eta \\frac{\\partial L}{\\partial \\mathbf{W}})" + }, + { + "bbox": [ + 312, + 243, + 545, + 266 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 312, + 243, + 545, + 266 + ], + "type": "inline_equation", + "content": "\\eta" + }, + { + "bbox": [ + 312, + 243, + 545, + 266 + ], + "type": "text", + "content": " is learning rate." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 312, + 267, + 357, + 277 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 267, + 357, + 277 + ], + "spans": [ + { + "bbox": [ + 312, + 267, + 357, + 277 + ], + "type": "text", + "content": "8: end for" + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 281, + 397, + 292 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 281, + 397, + 292 + ], + "spans": [ + { + "bbox": [ + 306, + 281, + 397, + 292 + ], + "type": "text", + "content": "Re-parameterization" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 306, + 293, + 545, + 315 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 293, + 545, + 315 + ], + "spans": [ + { + "bbox": [ + 306, + 293, + 545, + 315 + ], + "type": "text", + "content": "Input: The trained SNN with MPBN; total number of MPBN: " + }, + { + "bbox": [ + 306, + 293, + 545, + 315 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 306, + 293, + 545, + 315 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 306, + 316, + 545, + 340 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 316, + 545, + 340 + ], + "spans": [ + { + "bbox": [ + 306, + 316, + 545, + 340 + ], + "type": "text", + "content": "Output: The re-parameterized trained SNN without MPBN but diverse " + }, + { + "bbox": [ + 306, + 316, + 545, + 340 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{th}}" + }, + { + "bbox": [ + 306, + 316, + 545, + 340 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 312, + 342, + 545, + 388 + ], + "type": "list", + "angle": 0, + "index": 35, + "blocks": [ + { + "bbox": [ + 312, + 342, + 459, + 354 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 342, + 459, + 354 + ], + "spans": [ + { + "bbox": [ + 312, + 342, + 459, + 354 + ], + "type": "text", + "content": "1: for all " + }, + { + "bbox": [ + 312, + 342, + 459, + 354 + ], + "type": "inline_equation", + "content": "i = 1,2,\\ldots ,n" + }, + { + "bbox": [ + 312, + 342, + 459, + 354 + ], + "type": "text", + "content": " number do" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 312, + 354, + 545, + 377 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 354, + 545, + 377 + ], + "spans": [ + { + "bbox": [ + 312, + 354, + 545, + 377 + ], + "type": "text", + "content": "2: Fold the parameters of " + }, + { + "bbox": [ + 312, + 354, + 545, + 377 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 312, + 354, + 545, + 377 + ], + "type": "text", + "content": "-th MPBN into " + }, + { + "bbox": [ + 312, + 354, + 545, + 377 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 312, + 354, + 545, + 377 + ], + "type": "text", + "content": "-th " + }, + { + "bbox": [ + 312, + 354, + 545, + 377 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{th}}" + }, + { + "bbox": [ + 312, + 354, + 545, + 377 + ], + "type": "text", + "content": " by Eq. 10;" + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 312, + 380, + 357, + 388 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 380, + 357, + 388 + ], + "spans": [ + { + "bbox": [ + 312, + 380, + 357, + 388 + ], + "type": "text", + "content": "3: end for" + } + ] + } + ], + "index": 34 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 392, + 350, + 402 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 392, + 350, + 402 + ], + "spans": [ + { + "bbox": [ + 306, + 392, + 350, + 402 + ], + "type": "text", + "content": "Inference" + } + ] + } + ], + "index": 36 + }, + { + "bbox": [ + 306, + 404, + 545, + 428 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 404, + 545, + 428 + ], + "spans": [ + { + "bbox": [ + 306, + 404, + 545, + 428 + ], + "type": "text", + "content": "Input: The re-parameterized trained SNN; test dataset; total test iteration: " + }, + { + "bbox": [ + 306, + 404, + 545, + 428 + ], + "type": "inline_equation", + "content": "I_{\\mathrm{test}}" + }, + { + "bbox": [ + 306, + 404, + 545, + 428 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 37 + }, + { + "bbox": [ + 306, + 429, + 391, + 440 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 429, + 391, + 440 + ], + "spans": [ + { + "bbox": [ + 306, + 429, + 391, + 440 + ], + "type": "text", + "content": "Output: The output." + } + ] + } + ], + "index": 38 + }, + { + "bbox": [ + 312, + 442, + 544, + 536 + ], + "type": "list", + "angle": 0, + "index": 44, + "blocks": [ + { + "bbox": [ + 312, + 442, + 473, + 453 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 442, + 473, + 453 + ], + "spans": [ + { + "bbox": [ + 312, + 442, + 473, + 453 + ], + "type": "text", + "content": "1: for all " + }, + { + "bbox": [ + 312, + 442, + 473, + 453 + ], + "type": "inline_equation", + "content": "i = 1,2,\\ldots ,{I}_{\\text{test }}" + }, + { + "bbox": [ + 312, + 442, + 473, + 453 + ], + "type": "text", + "content": " iteration do" + } + ] + } + ], + "index": 39 + }, + { + "bbox": [ + 312, + 454, + 544, + 477 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 454, + 544, + 477 + ], + "spans": [ + { + "bbox": [ + 312, + 454, + 544, + 477 + ], + "type": "text", + "content": "2: Get mini-batch test data, " + }, + { + "bbox": [ + 312, + 454, + 544, + 477 + ], + "type": "inline_equation", + "content": "\\mathbf{x}_{\\mathrm{in}}(i)" + }, + { + "bbox": [ + 312, + 454, + 544, + 477 + ], + "type": "text", + "content": " and class label, " + }, + { + "bbox": [ + 312, + 454, + 544, + 477 + ], + "type": "inline_equation", + "content": "\\mathbf{y}(i)" + }, + { + "bbox": [ + 312, + 454, + 544, + 477 + ], + "type": "text", + "content": " in test dataset;" + } + ] + } + ], + "index": 40 + }, + { + "bbox": [ + 312, + 478, + 544, + 501 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 478, + 544, + 501 + ], + "spans": [ + { + "bbox": [ + 312, + 478, + 544, + 501 + ], + "type": "text", + "content": "3: Feed the " + }, + { + "bbox": [ + 312, + 478, + 544, + 501 + ], + "type": "inline_equation", + "content": "\\pmb{x}_{\\mathrm{in}}(i)" + }, + { + "bbox": [ + 312, + 478, + 544, + 501 + ], + "type": "text", + "content": " into the reparameterized SNN without MPBN;" + } + ] + } + ], + "index": 41 + }, + { + "bbox": [ + 312, + 502, + 514, + 514 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 502, + 514, + 514 + ], + "spans": [ + { + "bbox": [ + 312, + 502, + 514, + 514 + ], + "type": "text", + "content": "4: Calculate the SNN output, " + }, + { + "bbox": [ + 312, + 502, + 514, + 514 + ], + "type": "inline_equation", + "content": "\\pmb{o}_{\\mathrm{out}}(i)" + }, + { + "bbox": [ + 312, + 502, + 514, + 514 + ], + "type": "text", + "content": " by Eq. 3;" + } + ] + } + ], + "index": 42 + }, + { + "bbox": [ + 312, + 514, + 544, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 514, + 544, + 536 + ], + "spans": [ + { + "bbox": [ + 312, + 514, + 544, + 536 + ], + "type": "text", + "content": "5: Compare the classification factor " + }, + { + "bbox": [ + 312, + 514, + 544, + 536 + ], + "type": "inline_equation", + "content": "\\pmb{o}_{\\mathrm{out}}(i)" + }, + { + "bbox": [ + 312, + 514, + 544, + 536 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 312, + 514, + 544, + 536 + ], + "type": "inline_equation", + "content": "\\pmb{y}(i)" + }, + { + "bbox": [ + 312, + 514, + 544, + 536 + ], + "type": "text", + "content": " for classification." + } + ] + } + ], + "index": 43 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 312, + 538, + 356, + 548 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 538, + 356, + 548 + ], + "spans": [ + { + "bbox": [ + 312, + 538, + 356, + 548 + ], + "type": "text", + "content": "6: end for" + } + ] + } + ], + "index": 45 + }, + { + "bbox": [ + 304, + 574, + 545, + 658 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 574, + 545, + 658 + ], + "spans": [ + { + "bbox": [ + 304, + 574, + 545, + 658 + ], + "type": "text", + "content": "It can be seen that by absorbing some parameters from MPBN, " + }, + { + "bbox": [ + 304, + 574, + 545, + 658 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{th}}" + }, + { + "bbox": [ + 304, + 574, + 545, + 658 + ], + "type": "text", + "content": " will be transformed to another channel-wised " + }, + { + "bbox": [ + 304, + 574, + 545, + 658 + ], + "type": "inline_equation", + "content": "(\\tilde{V}_{\\mathrm{th}})_i" + }, + { + "bbox": [ + 304, + 574, + 545, + 658 + ], + "type": "text", + "content": ". In this way, the extra computation burden caused by MPBN will be eliminated again in the inference time. Furthermore, the diversity of the spiking neuron will be improved with abundant firing parameters as the learnable firing threshold in other work [3, 49]." + } + ] + } + ], + "index": 46 + }, + { + "bbox": [ + 306, + 670, + 427, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 670, + 427, + 682 + ], + "spans": [ + { + "bbox": [ + 306, + 670, + 427, + 682 + ], + "type": "text", + "content": "4.3. Training Framework" + } + ] + } + ], + "index": 47 + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": "In the paper, the spatial-temporal backpropagation (STBP) algorithm [51] is adopted to train the SNN mod" + } + ] + } + ], + "index": 48 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19423" + } + ] + } + ], + "index": 49 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 75, + 157, + 156 + ], + "blocks": [ + { + "bbox": [ + 53, + 75, + 157, + 156 + ], + "lines": [ + { + "bbox": [ + 53, + 75, + 157, + 156 + ], + "spans": [ + { + "bbox": [ + 53, + 75, + 157, + 156 + ], + "type": "image", + "image_path": "7dc6ade33d1190bb6aa0db95652147e83bc5f7dcd28ced2428a6446947c4bdb7.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 83, + 162, + 135, + 171 + ], + "lines": [ + { + "bbox": [ + 83, + 162, + 135, + 171 + ], + "spans": [ + { + "bbox": [ + 83, + 162, + 135, + 171 + ], + "type": "text", + "content": "(a) CIFAR-10" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 171, + 76, + 272, + 156 + ], + "blocks": [ + { + "bbox": [ + 171, + 76, + 272, + 156 + ], + "lines": [ + { + "bbox": [ + 171, + 76, + 272, + 156 + ], + "spans": [ + { + "bbox": [ + 171, + 76, + 272, + 156 + ], + "type": "image", + "image_path": "9532ddd02be7274b71ff4db54919280bc180d4795662696cb7b42e6d766f2355.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 198, + 162, + 253, + 171 + ], + "lines": [ + { + "bbox": [ + 198, + 162, + 253, + 171 + ], + "spans": [ + { + "bbox": [ + 198, + 162, + 253, + 171 + ], + "type": "text", + "content": "(b) CIFAR-100" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 182, + 287, + 231 + ], + "lines": [ + { + "bbox": [ + 46, + 182, + 287, + 231 + ], + "spans": [ + { + "bbox": [ + 46, + 182, + 287, + 231 + ], + "type": "text", + "content": "Figure 2: The accuracy curves of spiking ResNet20 with or without MPBN using 2 time steps on CIFAR-10 (left) and CIFAR-100 (right). The MPBN based SNNs obviously enjoy higher accuracy and easier convergence." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 252, + 287, + 324 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 252, + 287, + 324 + ], + "spans": [ + { + "bbox": [ + 46, + 252, + 287, + 324 + ], + "type": "text", + "content": "els. STBP treats the SNN model as a self-recurrent neural network thus enabling an error backpropagation mechanism following the same principles as in CNNs. However, there is still a problem impeding the direct training of SNNs. To demonstrate this problem, we formulate the gradient at the layer " + }, + { + "bbox": [ + 46, + 252, + 287, + 324 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 46, + 252, + 287, + 324 + ], + "type": "text", + "content": " by the chain rule, given by" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 334, + 287, + 373 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 334, + 287, + 373 + ], + "spans": [ + { + "bbox": [ + 47, + 334, + 287, + 373 + ], + "type": "interline_equation", + "content": "\\frac {\\partial L}{\\partial \\mathbf {W} ^ {l}} = \\sum_ {t} \\left(\\frac {\\partial L}{\\partial \\boldsymbol {o} ^ {(t) , l}} \\frac {\\partial \\boldsymbol {o} ^ {(t) , l}}{\\partial \\boldsymbol {u} ^ {(t) , l}} + \\frac {\\partial L}{\\partial \\boldsymbol {u} ^ {(t + 1) , l}} \\frac {\\partial \\boldsymbol {u} ^ {(t + 1) , l}}{\\partial \\boldsymbol {u} ^ {(t) , l}}\\right) \\frac {\\partial \\boldsymbol {u} ^ {(t) , l}}{\\partial \\mathbf {W} ^ {l}}, \\tag {11}", + "image_path": "14a7e4f39eefbfeb08345cd3ca62e1ca87db36ea4bca7b0b47e5244dff8022b9.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "spans": [ + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "type": "inline_equation", + "content": "\\frac{\\partial\\pmb{o}^{(t),l}}{\\partial\\pmb{u}^{(t),l}}" + }, + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "type": "text", + "content": " is the gradient of firing function at at " + }, + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "type": "text", + "content": "-th time step in " + }, + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "type": "text", + "content": "-th layer. Obviously, the non-differentiable firing activity of the spiking neuron will result in zero gradients everywhere, while infinity at " + }, + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{th}}" + }, + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "type": "text", + "content": ". Therefore, the gradient descent " + }, + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "type": "inline_equation", + "content": "(\\mathbf{W}^l\\gets \\mathbf{W}^l -\\eta \\frac{\\partial L}{\\partial\\mathbf{W}^l})" + }, + { + "bbox": [ + 46, + 374, + 287, + 483 + ], + "type": "text", + "content": " either freezes or updates to infinity in the backpropagation. To handle this problem, here, we also adopt the commonly used STE surrogate gradients as doing in other surrogate gradients (SG) methods [44, 20]. Mathematically, it is defined as:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 96, + 494, + 287, + 520 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 96, + 494, + 287, + 520 + ], + "spans": [ + { + "bbox": [ + 96, + 494, + 287, + 520 + ], + "type": "interline_equation", + "content": "\\frac {d \\boldsymbol {o}}{d \\boldsymbol {u}} = \\left\\{ \\begin{array}{l l} 1, & \\text {i f} 0 \\leq \\boldsymbol {u} \\leq 1 \\\\ 0, & \\text {o t h e r w i s e} \\end{array} \\right.. \\tag {12}", + "image_path": "9e3eb8250f35d99bbc91fc6d9843c799f3952a58dcc30af704befd4e8da1ed71.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 529, + 287, + 553 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 529, + 287, + 553 + ], + "spans": [ + { + "bbox": [ + 47, + 529, + 287, + 553 + ], + "type": "text", + "content": "Then, the SNN model can be trained end-to-end. The training and inference of our SNN are detailed in Algo. 1." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 563, + 140, + 575 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 563, + 140, + 575 + ], + "spans": [ + { + "bbox": [ + 47, + 563, + 140, + 575 + ], + "type": "text", + "content": "4.4. Ablation Study" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 582, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 287, + 713 + ], + "type": "text", + "content": "To verify the effectiveness of the MPBN, a lot of ablative studies using spiking ResNet20 architecture along with different time steps were conducted on the CIFAR-10 and CIFAR-100 datasets. The results of top-1 accuracy of these models are shown in Tab. 1. It's can be seen that the test accuracy of the SNNs with MPBN is always higher than these vanilla counterparts. For example, the accuracy of baseline SNN with 1 time step is " + }, + { + "bbox": [ + 46, + 582, + 287, + 713 + ], + "type": "inline_equation", + "content": "90.40\\%" + }, + { + "bbox": [ + 46, + 582, + 287, + 713 + ], + "type": "text", + "content": ", while with MPBN, it will increase up to " + }, + { + "bbox": [ + 46, + 582, + 287, + 713 + ], + "type": "inline_equation", + "content": "92.22\\%" + }, + { + "bbox": [ + 46, + 582, + 287, + 713 + ], + "type": "text", + "content": ", which is a huge improvement (more than " + }, + { + "bbox": [ + 46, + 582, + 287, + 713 + ], + "type": "inline_equation", + "content": "2.0\\%" + }, + { + "bbox": [ + 46, + 582, + 287, + 713 + ], + "type": "text", + "content": ") in the SNN field. Moreover, we also show the test accuracy curves of ResNet20 using MPBN and its" + } + ] + } + ], + "index": 11 + }, + { + "type": "table", + "bbox": [ + 318, + 91, + 535, + 258 + ], + "blocks": [ + { + "bbox": [ + 340, + 71, + 511, + 83 + ], + "lines": [ + { + "bbox": [ + 340, + 71, + 511, + 83 + ], + "spans": [ + { + "bbox": [ + 340, + 71, + 511, + 83 + ], + "type": "text", + "content": "Table 1: Ablation experiments for MPBN." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 318, + 91, + 535, + 258 + ], + "lines": [ + { + "bbox": [ + 318, + 91, + 535, + 258 + ], + "spans": [ + { + "bbox": [ + 318, + 91, + 535, + 258 + ], + "type": "table", + "html": "
DatasetMethodTime stepAccuracy
CIFAR-10baseline190.40%
w/ MPBN192.22%
baseline292.80%
w/ MPBN293.54%
baseline493.85%
w/ MPBN494.28%
CIFAR-100baseline167.94%
w/ MPBN168.36%
baseline270.18%
w/ MPBN270.79%
baseline471.77%
w/ MPBN472.30%
", + "image_path": "6f0f77407c2aca89fdc1b019e0b3bf428daa18301e81702c2981fa7afb370203.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_body" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 312, + 270, + 424, + 344 + ], + "blocks": [ + { + "bbox": [ + 312, + 270, + 424, + 344 + ], + "lines": [ + { + "bbox": [ + 312, + 270, + 424, + 344 + ], + "spans": [ + { + "bbox": [ + 312, + 270, + 424, + 344 + ], + "type": "image", + "image_path": "6863b9ac56d0690ab487204ebbbc6ece166455ad1ad0c842df883d19db9f0313.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 348, + 350, + 388, + 361 + ], + "lines": [ + { + "bbox": [ + 348, + 350, + 388, + 361 + ], + "spans": [ + { + "bbox": [ + 348, + 350, + 388, + 361 + ], + "type": "text", + "content": "(a) MPBN" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 306, + 371, + 545, + 395 + ], + "lines": [ + { + "bbox": [ + 306, + 371, + 545, + 395 + ], + "spans": [ + { + "bbox": [ + 306, + 371, + 545, + 395 + ], + "type": "text", + "content": "Figure 3: The 1D loss landscape of spiking ResNet20 with and without MPBN." + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 430, + 270, + 541, + 344 + ], + "blocks": [ + { + "bbox": [ + 430, + 270, + 541, + 344 + ], + "lines": [ + { + "bbox": [ + 430, + 270, + 541, + 344 + ], + "spans": [ + { + "bbox": [ + 430, + 270, + 541, + 344 + ], + "type": "image", + "image_path": "5e6dea99328c8638d89687bd97a184f1994ea19a3d6e40db450ad2569f5c2e5e.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 465, + 350, + 504, + 361 + ], + "lines": [ + { + "bbox": [ + 465, + 350, + 504, + 361 + ], + "spans": [ + { + "bbox": [ + 465, + 350, + 504, + 361 + ], + "type": "text", + "content": "(b) Vanilla" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_caption" + } + ], + "index": 16 + }, + { + "bbox": [ + 305, + 417, + 545, + 489 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 417, + 545, + 489 + ], + "spans": [ + { + "bbox": [ + 305, + 417, + 545, + 489 + ], + "type": "text", + "content": "vanilla counterpart with 2 time steps on CIFAR-10/100 during training in Fig. 2. It can be observed obviously that the SNNs with MPBN also perform better on convergence speed. To sum up, the proposed MPBN can both improve accuracy and convergence speed, which are very important aspects in deep learning." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 496, + 403, + 510 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 496, + 403, + 510 + ], + "spans": [ + { + "bbox": [ + 306, + 496, + 403, + 510 + ], + "type": "text", + "content": "4.5. Loss Landscape" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 305, + 514, + 545, + 646 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 514, + 545, + 646 + ], + "spans": [ + { + "bbox": [ + 305, + 514, + 545, + 646 + ], + "type": "text", + "content": "We further inspect the 1D loss landscapes [36] of the SNNs with or without MPBN using spiking ResNet20 architecture in 2 time steps to show why the MPBN can improve accuracy and convergence speed in Fig. 3. It can be observed that the loss landscape of the SNN model with MPBN is flatter than that of the SNN without MPBN. This indicates that the MPBN makes the landscape of the corresponding optimization problem smoother [36], thus making the gradients more predictive and network faster convergence. The results here provide convincing evidence for ablation studies in Section 4.4." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 306, + 658, + 387, + 671 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 658, + 387, + 671 + ], + "spans": [ + { + "bbox": [ + 306, + 658, + 387, + 671 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 305, + 677, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 714 + ], + "type": "text", + "content": "In this section, abundant experiments were conducted to verify the effectiveness of the MPBN using widely-used spiking ResNet20 [44, 46], VGG16 [44], ResNet18 [11]," + } + ] + } + ], + "index": 23 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19424" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 96, + 91, + 500, + 523 + ], + "blocks": [ + { + "bbox": [ + 182, + 70, + 411, + 83 + ], + "lines": [ + { + "bbox": [ + 182, + 70, + 411, + 83 + ], + "spans": [ + { + "bbox": [ + 182, + 70, + 411, + 83 + ], + "type": "text", + "content": "Table 2: Comparison with SoTA methods on CIFAR-10." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 96, + 91, + 500, + 523 + ], + "lines": [ + { + "bbox": [ + 96, + 91, + 500, + 523 + ], + "spans": [ + { + "bbox": [ + 96, + 91, + 500, + 523 + ], + "type": "table", + "html": "
DatasetMethodTypeArchitectureTimestepAccuracy
CIFAR-10SpikeNorm [46]ANN2SNNVGG16250091.55%
Hybrid-Train [45]Hybrid trainingVGG1620092.02%
Spike-basedBP [34]SNN trainingResNet1110090.95%
Joint A-SNN [19]SNN trainingResNet18495.45%
GLIF [60]SNN trainingResNet19294.44%
PLIF [12]SNN trainingPLIFNet893.50%
Diet-SNN [44]SNN trainingVGG16592.70%
1093.44%
ResNet20591.78%
1092.54%
RecDis-SNN [20]SNN trainingResNet19293.64%
495.53%
695.55%
Dspike [38]SNN trainingResNet20293.13%
493.66%
694.25%
STBP-tdBN [62]SNN trainingResNet19292.34%
492.92%
693.16%
TET [7]SNN trainingResNet19294.16%
494.44%
694.50%
Real Spike [21]SNN trainingResNet19295.31%
495.51%
696.10%
InfLoR-SNN [16]SNN trainingResNet20593.01%
1093.65%
MPBNSNN trainingResNet19196.06%±0.10
296.47%±0.08
ResNet20192.22%±0.11
293.54%±0.09
494.28%±0.07
VGG16293.96%±0.09
494.44%±0.08
", + "image_path": "588ccc23c9aad74dcdf1526efc833a637967f1adfed9d739bdca805b17c47303.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 542, + 289, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 542, + 289, + 711 + ], + "spans": [ + { + "bbox": [ + 46, + 542, + 289, + 711 + ], + "type": "text", + "content": "ResNet19 [62], and ResNet34 [11] on both static datasets including CIFAR-10 [32], CIFAR-100 [32], and ImageNet [6], and one neuromorphic dataset, CIFAR10-DVS [35]. The specific introduction for these datasets has been detailed in many recent works [62, 44, 21, 38]. Here, we mainly introduce these hyper-parameters and data preprocessing in detail. We used the widely adopted LIF neuron in our SNN models as other works about direct training methods [44, 46]. These hyper-parameters for LIF neuron about the initial firing threshold " + }, + { + "bbox": [ + 46, + 542, + 289, + 711 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{th}}" + }, + { + "bbox": [ + 46, + 542, + 289, + 711 + ], + "type": "text", + "content": " and the membrane potential decaying constant " + }, + { + "bbox": [ + 46, + 542, + 289, + 711 + ], + "type": "inline_equation", + "content": "\\tau_{\\mathrm{decay}}" + }, + { + "bbox": [ + 46, + 542, + 289, + 711 + ], + "type": "text", + "content": " are 0.5 and 0.25 respectively. For static image datasets, since encoding the 8-bit RGB images into 1-bit spikes will lose too much information, we use an ANN-like convolutional layer and a LIF layer to encode the" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 305, + 542, + 545, + 566 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 542, + 545, + 566 + ], + "spans": [ + { + "bbox": [ + 305, + 542, + 545, + 566 + ], + "type": "text", + "content": "images to spikes for all the rest of the layers, as in recent works [62, 44, 21, 38]." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 305, + 574, + 483, + 588 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 574, + 483, + 588 + ], + "spans": [ + { + "bbox": [ + 305, + 574, + 483, + 588 + ], + "type": "text", + "content": "5.1. Comparison with SoTA Methods" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": "CIFAR-10. On CIFAR-10, we trained our SNN model using the SGD optimizer with 0.9 momentum. The initial learning rate is 0.1 and decays to 0 in cosine form. The total training time is 400 epochs. To fairly compare with these recent SoTA methods [38, 20, 16], we also adopt data normalization, random horizontal flipping, cropping, and cutout [8] for data augmentation. We run three times for each experiment to report the \"mean ± std\" in Tab. 2. It can be seen that our models can outperform other methods over all these chosen widely adopted architectures with" + } + ] + } + ], + "index": 5 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 758 + ], + "type": "text", + "content": "19425" + } + ] + } + ], + "index": 6 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 97, + 91, + 496, + 450 + ], + "blocks": [ + { + "bbox": [ + 179, + 70, + 414, + 83 + ], + "lines": [ + { + "bbox": [ + 179, + 70, + 414, + 83 + ], + "spans": [ + { + "bbox": [ + 179, + 70, + 414, + 83 + ], + "type": "text", + "content": "Table 3: Comparison with SoTA methods on CIFAR-100." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 97, + 91, + 496, + 450 + ], + "lines": [ + { + "bbox": [ + 97, + 91, + 496, + 450 + ], + "spans": [ + { + "bbox": [ + 97, + 91, + 496, + 450 + ], + "type": "table", + "html": "
DatasetMethodTypeArchitectureTimestepAccuracy
CIFAR-100SpikeNorm [46]ANN2SNNResNet20250064.09%
RMP [23]ANN2SNNResNet20204867.82%
Hybrid-Train [45]Hybrid trainingVGG1112567.90%
IM-Loss [15]SNN trainingVGG16570.18%
Joint A-SNN [19]SNN trainingResNet18477.39%
ResNet34479.76%
Dspike [38]SNN trainingResNet20271.68%
473.35%
674.24%
TET [7]SNN trainingResNet19272.87%
474.47%
674.72%
RecDis-SNN [20]SNN trainingResNet19474.10%
VGG16569.88%
InfLoR-SNN [16]SNN trainingResNet20571.19%
VGG16571.56%
Real Spike [21]SNN trainingResNet20566.60%
VGG16570.62%
GLIF [60]SNN trainingResNet19275.48%
477.05%
TEBN [10]SNN trainingResNet19275.86%
476.13%
676.41%
MPBNSNN trainingVGG16474.74%±0.11
ResNet19178.71%±0.10
279.51%±0.07
ResNet20270.79%±0.08
472.30%±0.08
", + "image_path": "546326ffe740b108e04f1bdd8ae06bebe5901e2592bea9f1b6328201acdfbd66.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "table", + "bbox": [ + 105, + 482, + 489, + 613 + ], + "blocks": [ + { + "bbox": [ + 183, + 460, + 409, + 473 + ], + "lines": [ + { + "bbox": [ + 183, + 460, + 409, + 473 + ], + "spans": [ + { + "bbox": [ + 183, + 460, + 409, + 473 + ], + "type": "text", + "content": "Table 4: Comparison with SoTA methods on ImageNet." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 105, + 482, + 489, + 613 + ], + "lines": [ + { + "bbox": [ + 105, + 482, + 489, + 613 + ], + "spans": [ + { + "bbox": [ + 105, + 482, + 489, + 613 + ], + "type": "table", + "html": "
DatasetMethodTypeArchitectureTimestepAccuracy
ImageNetSTBP-tdBN [62]SNN trainingResNet34663.72%
TET [7]SNN trainingResNet34664.79%
MS-ResNet [27]SNN trainingResNet18663.10%
OTT [54]SNN trainingResNet34663.10%
Real Spike [21]SNN trainingResNet18463.68%
SEW ResNet [11]SNN trainingResNet18463.18%
ResNet34467.04%
MPBNSNN trainingResNet18463.14%±0.08
ResNet34464.71%±0.09
", + "image_path": "85a3e33687344eab1d6bdedec19f703bad42504dd32e4baba3e5792c1d762461.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_body" + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 633, + 288, + 706 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 633, + 288, + 706 + ], + "spans": [ + { + "bbox": [ + 46, + 633, + 288, + 706 + ], + "type": "text", + "content": "fewer time steps. For example, The accuracy of spiking ResNet19 trained with MPBN with only 1 time step can be up to " + }, + { + "bbox": [ + 46, + 633, + 288, + 706 + ], + "type": "inline_equation", + "content": "96.06\\%" + }, + { + "bbox": [ + 46, + 633, + 288, + 706 + ], + "type": "text", + "content": ", while the Real Spike [21] needs 6 time steps to reach a comparable result and the RecDis-SNN [61] even still underperforms " + }, + { + "bbox": [ + 46, + 633, + 288, + 706 + ], + "type": "inline_equation", + "content": "0.51\\%" + }, + { + "bbox": [ + 46, + 633, + 288, + 706 + ], + "type": "text", + "content": " with 6 time steps. This superiority can also be observed in the results regarding the spiking" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 306, + 633, + 402, + 644 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 633, + 402, + 644 + ], + "spans": [ + { + "bbox": [ + 306, + 633, + 402, + 644 + ], + "type": "text", + "content": "ResNet20 and VGG16." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "CIFAR-100. For CIFAR-100, we adopted the same settings as in CIFAR-10. The proposed MPBN also performs well on CIFAR-100. It can be seen that our method gets the best accuracy over all these networks even with fewer time steps. For instants, the ResNet19 trained with MPBN" + } + ] + } + ], + "index": 6 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19426" + } + ] + } + ], + "index": 7 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 94, + 91, + 501, + 224 + ], + "blocks": [ + { + "bbox": [ + 172, + 70, + 420, + 83 + ], + "lines": [ + { + "bbox": [ + 172, + 70, + 420, + 83 + ], + "spans": [ + { + "bbox": [ + 172, + 70, + 420, + 83 + ], + "type": "text", + "content": "Table 5: Comparison with SoTA methods on CIFAR10-DVS." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 94, + 91, + 501, + 224 + ], + "lines": [ + { + "bbox": [ + 94, + 91, + 501, + 224 + ], + "spans": [ + { + "bbox": [ + 94, + 91, + 501, + 224 + ], + "type": "table", + "html": "
DatasetMethodTypeArchitectureTimestepAccuracy
CIFAR10-DVSRollout [33]RolloutDenseNet1066.80%
LIAF-Net [53]Conv3DLIAF-Net1071.70%
LIAF-Net [53]LIAFLIAF-Net1070.40%
STBP-tdBN [62]SNN trainingResNet191067.80%
RecDis-SNN [20]SNN trainingResNet191072.42%
Real Spike [21]SNN trainingResNet191072.85%
ResNet201078.00%
MPBNSNN trainingResNet191074.40%±0.20
ResNet201078.70%±0.10
", + "image_path": "071584ea156ed8f7f9430a0a5a67f61e32c6d8cee608a8a8cde4de1280f7fde7.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 243, + 287, + 290 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 243, + 287, + 290 + ], + "spans": [ + { + "bbox": [ + 46, + 243, + 287, + 290 + ], + "type": "text", + "content": "can achieve " + }, + { + "bbox": [ + 46, + 243, + 287, + 290 + ], + "type": "inline_equation", + "content": "78.71\\%" + }, + { + "bbox": [ + 46, + 243, + 287, + 290 + ], + "type": "text", + "content": " top-1 accuracy with only 1 time step, which outperforms other SoTA methods such as TET, GLIF, TEBN, and RecDis-SNN even with 4 or 6 time steps about " + }, + { + "bbox": [ + 46, + 243, + 287, + 290 + ], + "type": "inline_equation", + "content": "1.66\\% -3.99\\%" + }, + { + "bbox": [ + 46, + 243, + 287, + 290 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 291, + 287, + 458 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 291, + 287, + 458 + ], + "spans": [ + { + "bbox": [ + 46, + 291, + 287, + 458 + ], + "type": "text", + "content": "ImageNet. On ImageNet, we used standard data normalization, random horizontal flipping, and cropping for data augmentation and trained the networks for 320 epochs as in [11]. The optimizer setting also keeps the same with CIFAR datasets. The results for ImageNet are presented in Tab. 4. It can be seen that the accuracy of our method is better than that of these recent SoTA methods, only relatively smaller compared with SEW ResNet [11] for spiking ResNet34. However, SEW ResNet is not a typical SNN model. It adopts the activation before addition form-based ResNet and its blocks will fire positive integer spikes. In this way, the event-driven and multiplication-addition transform advantages of SNNs will be lost. While we adopt the original ResNet, which fires standard binary spikes." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 459, + 287, + 543 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 459, + 287, + 543 + ], + "spans": [ + { + "bbox": [ + 46, + 459, + 287, + 543 + ], + "type": "text", + "content": "CIFAR10-DVS. We also adopted the neuromorphic dataset, CIFAR10-DVS in the paper to verify the effectiveness of the MPBN. We also split the dataset into 9K training images and 1K test images, and resize them to " + }, + { + "bbox": [ + 46, + 459, + 287, + 543 + ], + "type": "inline_equation", + "content": "48 \\times 48" + }, + { + "bbox": [ + 46, + 459, + 287, + 543 + ], + "type": "text", + "content": " for data augmentation as in [51, 21]. The learning rate is 0.01 and other settings are the same as CIFAR-10. It can be seen that the MPBN also shows superiority in this dataset." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 549, + 185, + 561 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 549, + 185, + 561 + ], + "spans": [ + { + "bbox": [ + 47, + 549, + 185, + 561 + ], + "type": "text", + "content": "5.2. Extension of the MPBN" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 567, + 287, + 675 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 567, + 287, + 675 + ], + "spans": [ + { + "bbox": [ + 46, + 567, + 287, + 675 + ], + "type": "text", + "content": "In CNNs, the most widely used BN is channelwised. This is because element-wised BNs are very time-consuming and can not be folded into weights, otherwise, the channel-wised weight-sharing mechanism will be destroyed. However, the MPBN adopts the firing thresholdfolded manner and the firing threshold need not keep the same along the channels, therefore, MPBN can use the element-wised form freely. In this way, " + }, + { + "bbox": [ + 46, + 567, + 287, + 675 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{th}}" + }, + { + "bbox": [ + 46, + 567, + 287, + 675 + ], + "type": "text", + "content": " will be transformed to element-wised ones as follows," + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 67, + 682, + 287, + 717 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 682, + 287, + 717 + ], + "spans": [ + { + "bbox": [ + 67, + 682, + 287, + 717 + ], + "type": "interline_equation", + "content": "(\\tilde {\\boldsymbol {V}} _ {\\mathrm {t h}}) _ {i, j, k} = \\frac {(V _ {\\mathrm {t h}} - \\beta_ {i , j , k}) \\sqrt {\\sigma_ {i , j , k} ^ {2}}}{\\boldsymbol {\\lambda} _ {i , j , k}} + \\boldsymbol {\\mu} _ {i, j, k}, \\tag {13}", + "image_path": "449f5ede755ca9bdf3dd19dcb4239b1f85481a5404a21b81a93102c2aaa25b89.jpg" + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 309, + 274, + 543, + 347 + ], + "blocks": [ + { + "bbox": [ + 305, + 242, + 545, + 266 + ], + "lines": [ + { + "bbox": [ + 305, + 242, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 305, + 242, + 545, + 266 + ], + "type": "text", + "content": "Table 6: Comparison with learnable firing threshold methods." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 309, + 274, + 543, + 347 + ], + "lines": [ + { + "bbox": [ + 309, + 274, + 543, + 347 + ], + "spans": [ + { + "bbox": [ + 309, + 274, + 543, + 347 + ], + "type": "table", + "html": "
DatasetMethodTime stepAccuracy
CIFAR-10channel-wised494.28%
element-wised494.42%
CIFAR-100channel-wised472.30%
element-wised472.49%
", + "image_path": "207bdb3c0906f30b6aeefabaac5408db75f35a71e099b57775946db7d928fe93.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 365, + 545, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 365, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 304, + 365, + 545, + 498 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 365, + 545, + 498 + ], + "type": "inline_equation", + "content": "(\\tilde{V}_{\\mathrm{th}})_{i,j,k}" + }, + { + "bbox": [ + 304, + 365, + 545, + 498 + ], + "type": "text", + "content": " is the transformed firing threshold of the neuron comes from " + }, + { + "bbox": [ + 304, + 365, + 545, + 498 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 365, + 545, + 498 + ], + "type": "text", + "content": "-th channel in the spatial position " + }, + { + "bbox": [ + 304, + 365, + 545, + 498 + ], + "type": "inline_equation", + "content": "(j,k)" + }, + { + "bbox": [ + 304, + 365, + 545, + 498 + ], + "type": "text", + "content": ". To investigate the performance of the element-wised MPBN, here we also provide a comparison of the vanilla MPBN and its extension. The results of top-1 accuracy of the spiking ResNet20 with 4 time steps on CIFAR datasets are shown in Tab. 6. Though the two versions all perform well, the element-wised MPBN is relatively better than the channel-wised MPBN. This may be because element-wised MPBN can learn more firing threshold values, which means a richer representation ability for SNNs." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 507, + 379, + 520 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 507, + 379, + 520 + ], + "spans": [ + { + "bbox": [ + 306, + 507, + 379, + 520 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 527, + 545, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 527, + 545, + 647 + ], + "spans": [ + { + "bbox": [ + 304, + 527, + 545, + 647 + ], + "type": "text", + "content": "In the paper, we advocated adding the MPBN before the firing function to regulate the disturbed data flow again. We also provided a training-inference-decoupled reparameterization technique to fold the trained MPBN into the firing threshold to eliminate the extra time burden induced by MPBN in the inference time. Furthermore, the channel-wised and element-wised MPBN in different granularities were explored. Extensive experiments verified that the proposed MPBN can consistently achieve good performance." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 658, + 399, + 671 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 658, + 399, + 671 + ], + "spans": [ + { + "bbox": [ + 306, + 658, + 399, + 671 + ], + "type": "text", + "content": "Acknowledgment" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "content": "This work is supported by grants from the National Natural Science Foundation of China under contracts No.12202412 and No.12202413." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19427" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 16, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 190 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 190 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 190 + ], + "type": "text", + "content": "[1] Filipp Akopyan, Jun Sawada, Andrew Cassidy, Rodrigo Alvarez-Icaza, John Arthur, Paul Merolla, Nabil Imam, Yutaka Nakamura, Pallab Datta, Gi-Joon Nam, Brian Taba, Michael Beakes, Bernard Brezzo, Jente Kuang, Rajit Manohar, W.P. Risk, Bryan Jackson, and Dharmendra Modha. Truenorth: Design and tool flow of a 65 mw 1 million neuron programmable neurosynaptic chip. Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on, 34:1537-1557, 10 2015. 1" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 191, + 287, + 224 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 191, + 287, + 224 + ], + "spans": [ + { + "bbox": [ + 53, + 191, + 287, + 224 + ], + "type": "text", + "content": "[2] Jimmy Lei Ba, Jamie Ryan Kiros, and Geoffrey E Hinton. Layer normalization. arXiv preprint arXiv:1607.06450, 2016. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 225, + 287, + 258 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 225, + 287, + 258 + ], + "spans": [ + { + "bbox": [ + 53, + 225, + 287, + 258 + ], + "type": "text", + "content": "[3] G. Bellec, D. Salaj, A. Subramoney, R. Legenstein, and W. Maass. Long short-term memory and learning-to-learn in networks of spiking neurons, 2018. 4" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 259, + 287, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 259, + 287, + 293 + ], + "spans": [ + { + "bbox": [ + 53, + 259, + 287, + 293 + ], + "type": "text", + "content": "[4] Xiang Cheng, Yunzhe Hao, Jiaming Xu, and Bo Xu. Lisnn: Improving spiking neural networks with lateral interactions for robust object recognition. pages 1519-1525, 07 2020. 4" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 294, + 287, + 348 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 294, + 287, + 348 + ], + "spans": [ + { + "bbox": [ + 53, + 294, + 287, + 348 + ], + "type": "text", + "content": "[5] Mike Davies, Narayan Srinivasa, Tsung-Han Lin, Gautham Chinya, Andrew Lines, Andreas Wild, Hong Wang, and Deepak Mathaikutty. Loihi: A neuromorphic manycore processor with on-chip learning. IEEE Micro, 38:82 - 99, 01 2018. 1" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 350, + 287, + 384 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 350, + 287, + 384 + ], + "spans": [ + { + "bbox": [ + 53, + 350, + 287, + 384 + ], + "type": "text", + "content": "[6] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Fei-Fei Li. Imagenet: a large-scale hierarchical image database. pages 248-255, 06 2009. 6" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 384, + 287, + 429 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 384, + 287, + 429 + ], + "spans": [ + { + "bbox": [ + 53, + 384, + 287, + 429 + ], + "type": "text", + "content": "[7] Shikuang Deng, Yuhang Li, Shanghang Zhang, and Shi Gu. Temporal efficient training of spiking neural network via gradient re-weighting. In International Conference on Learning Representations, 2022. 6, 7" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 430, + 287, + 462 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 430, + 287, + 462 + ], + "spans": [ + { + "bbox": [ + 53, + 430, + 287, + 462 + ], + "type": "text", + "content": "[8] Terrance DeVries and Graham W. Taylor. Improved regularization of convolutional neural networks with cutout, 2017. 6" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 464, + 287, + 486 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 464, + 287, + 486 + ], + "spans": [ + { + "bbox": [ + 53, + 464, + 287, + 486 + ], + "type": "text", + "content": "[9] Travis DeWolf. Spiking neural networks take control. Science Robotics, 6(58):eabk3268, 2021. 1" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 487, + 287, + 542 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 487, + 287, + 542 + ], + "spans": [ + { + "bbox": [ + 48, + 487, + 287, + 542 + ], + "type": "text", + "content": "[10] Chaoteng Duan, Jianhao Ding, Shiyan Chen, Zhaofei Yu, and Tiejun Huang. Temporal effective batch normalization in spiking neural networks. In Alice H. Oh, Alekh Agarwal, Danielle Belgrave, and Kyunghyun Cho, editors, Advances in Neural Information Processing Systems, 2022. 1, 3, 7" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 544, + 287, + 576 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 544, + 287, + 576 + ], + "spans": [ + { + "bbox": [ + 48, + 544, + 287, + 576 + ], + "type": "text", + "content": "[11] Wei Fang, Zhaofei Yu, Yanqi Chen, Tiejun Huang, and Yonghong Tian. Deep residual learning in spiking neural networks. 2021. 2, 5, 6, 7, 8" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 577, + 287, + 621 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 577, + 287, + 621 + ], + "spans": [ + { + "bbox": [ + 48, + 577, + 287, + 621 + ], + "type": "text", + "content": "[12] Wei Fang, Zhaofei yu, Yanqi Chen, Timothee Masquelier, Tiejun Huang, and Yonghong Tian. Incorporating learnable membrane time constant to enhance learning of spiking neural networks. 08 2021. 1, 3, 6" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 622, + 287, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 622, + 287, + 645 + ], + "spans": [ + { + "bbox": [ + 48, + 622, + 287, + 645 + ], + "type": "text", + "content": "[13] Samanwoy Ghosh-Dastidar and Hojjat Adeli. Spiking neural networks. Int. J. Neural Syst., 19:295-308, 08 2009. 1" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 646, + 287, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 646, + 287, + 678 + ], + "spans": [ + { + "bbox": [ + 48, + 646, + 287, + 678 + ], + "type": "text", + "content": "[14] Yufei Guo and Yuanpei Chen. Neuroclip: Neuromorphic data understanding by clip and snn. arXiv preprint arXiv:2306.12073, 2023. 1" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 679, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 679, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 679, + 287, + 713 + ], + "type": "text", + "content": "[15] Yufei Guo, Yuanpei Chen, Liwen Zhang, Xiaode Liu, Yinglei Wang, Xuhui Huang, and Zhe Ma. IM-loss: Information maximization loss for spiking neural networks. In Alice H." + } + ] + } + ], + "index": 15 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 31, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "type": "text", + "content": "Oh, Alekh Agarwal, Danielle Belgrave, and Kyunghyun Cho, editors, Advances in Neural Information Processing Systems, 2022. 7" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 107, + 545, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 107, + 545, + 173 + ], + "spans": [ + { + "bbox": [ + 308, + 107, + 545, + 173 + ], + "type": "text", + "content": "[16] Yufei Guo, Yuanpei Chen, Liwen Zhang, YingLei Wang, Xiaode Liu, Xinyi Tong, Yuanyuan Ou, Xuhui Huang, and Zhe Ma. Reducing information loss for spiking neural networks. In Computer Vision-ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XI, pages 36-52. Springer, 2022. 6, 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 175, + 545, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 175, + 545, + 206 + ], + "spans": [ + { + "bbox": [ + 308, + 175, + 545, + 206 + ], + "type": "text", + "content": "[17] Yufei Guo, Xuhui Huang, and Zhe Ma. Direct learning-based deep spiking neural networks: a review. Frontiers in Neuroscience, 17:1209795, 2023. 1, 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 208, + 545, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 208, + 545, + 262 + ], + "spans": [ + { + "bbox": [ + 308, + 208, + 545, + 262 + ], + "type": "text", + "content": "[18] Yufei Guo, Xiaode Liu, Yuanpei Chen, Liwen Zhang, Wei-hang Peng, Yuhan Zhang, Xuhui Huang, and Zhe Ma. Rmp-loss: Regularizing membrane potential distribution for spiking neural networks. arXiv preprint arXiv:2308.06787, 2023.2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 263, + 545, + 319 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 263, + 545, + 319 + ], + "spans": [ + { + "bbox": [ + 308, + 263, + 545, + 319 + ], + "type": "text", + "content": "[19] Yufei Guo, Weihang Peng, Yuanpei Chen, Liwen Zhang, Xiaode Liu, Xuhui Huang, and Zhe Ma. Joint a-snn: Joint training of artificial and spiking neural networks via self-distillation and weight factorization. Pattern Recognition, page 109639, 2023. 1, 2, 6, 7" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 320, + 545, + 386 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 320, + 545, + 386 + ], + "spans": [ + { + "bbox": [ + 308, + 320, + 545, + 386 + ], + "type": "text", + "content": "[20] Yufei Guo, Xinyi Tong, Yuanpei Chen, Liwen Zhang, Xiaode Liu, Zhe Ma, and Xuhui Huang. Recdis-snn: Rectifying membrane potential distribution for directly training spiking neural networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 326-335, June 2022. 2, 3, 5, 6, 7, 8" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 388, + 545, + 442 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 388, + 545, + 442 + ], + "spans": [ + { + "bbox": [ + 308, + 388, + 545, + 442 + ], + "type": "text", + "content": "[21] Yufei Guo, Liwen Zhang, Yuanpei Chen, Xinyi Tong, Xiaode Liu, YingLei Wang, Xuhui Huang, and Zhe Ma. Real spike: Learning real-valued spikes for spiking neural networks. In European Conference on Computer Vision, pages 52-68. Springer, 2022. 1, 3, 4, 6, 7, 8" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 443, + 545, + 476 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 443, + 545, + 476 + ], + "spans": [ + { + "bbox": [ + 308, + 443, + 545, + 476 + ], + "type": "text", + "content": "[22] Bing Han and Kaushik Roy. Deep spiking neural network: Energy efficiency through time based coding. In ECCV, pages 388-404. Springer, 2020. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 477, + 545, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 477, + 545, + 521 + ], + "spans": [ + { + "bbox": [ + 308, + 477, + 545, + 521 + ], + "type": "text", + "content": "[23] Bing Han, Gopalakrishnan Srinivasan, and Kaushik Roy. Rmp-snn: Residual membrane potential neuron for enabling deeper high-accuracy and low-latency spiking neural network. pages 13555–13564, 06 2020. 7" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 522, + 545, + 566 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 522, + 545, + 566 + ], + "spans": [ + { + "bbox": [ + 308, + 522, + 545, + 566 + ], + "type": "text", + "content": "[24] Yunzhe Hao, Xuhui Huang, Meng Dong, and Bo Xu. A biologically plausible supervised learning method for spiking neural networks using the symmetric stdp rule. Neural Networks, 121, 09 2019. 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 567, + 545, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 567, + 545, + 600 + ], + "spans": [ + { + "bbox": [ + 308, + 567, + 545, + 600 + ], + "type": "text", + "content": "[25] Zecheng Hao, Tong Bu, Jianhao Ding, Tiejun Huang, and Zhaofei Yu. Reducing ann-snn conversion error through residual membrane potential, 2023. 2" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 601, + 545, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 601, + 545, + 634 + ], + "spans": [ + { + "bbox": [ + 308, + 601, + 545, + 634 + ], + "type": "text", + "content": "[26] Zecheng Hao, Jianhao Ding, Tong Bu, Tiejun Huang, and Zhaofei Yu. Bridging the gap between anns and snns by calibrating offset spikes, 2023. 2" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 635, + 545, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 635, + 545, + 668 + ], + "spans": [ + { + "bbox": [ + 308, + 635, + 545, + 668 + ], + "type": "text", + "content": "[27] Yifan Hu, Yujie Wu, Lei Deng, and Guoqi Li. Advancing residual learning towards powerful deep spiking neural networks. arXiv preprint arXiv:2112.08954, 2021. 7" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 308, + 669, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 669, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 669, + 545, + 712 + ], + "type": "text", + "content": "[28] Shin-ichi Ikegawa, Ryuji Saiin, Yoshihide Sawada, and Naotake Natori. Rethinking the role of normalization and residual blocks for spiking neural networks. Sensors, 22(8), 2022. 1, 3" + } + ] + } + ], + "index": 30 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19428" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 712 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[29] Sergey Ioffe and Christian Szegedy. Batch normalization: Accelerating deep network training by reducing internal covariate shift. In International conference on machine learning, pages 448-456. PMLR, 2015. 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 119, + 287, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 119, + 287, + 173 + ], + "spans": [ + { + "bbox": [ + 48, + 119, + 287, + 173 + ], + "type": "text", + "content": "[30] Seijoon Kim, Seongsik Park, Byunggook Na, and Sungroh Yoon. Spiking-yolo: spiking neural network for energy-efficient object detection. In Proceedings of the AAAI conference on artificial intelligence, volume 34, pages 11270-11277, 2020. 1" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 175, + 287, + 207 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 175, + 287, + 207 + ], + "spans": [ + { + "bbox": [ + 48, + 175, + 287, + 207 + ], + "type": "text", + "content": "[31] Y. Kim and P. Panda. Revisiting batch normalization for training low-latency deep spiking neural networks from scratch, 2020. 1, 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 210, + 287, + 232 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 210, + 287, + 232 + ], + "spans": [ + { + "bbox": [ + 48, + 210, + 287, + 232 + ], + "type": "text", + "content": "[32] Alex Krizhevsky, Vinod Nair, and Geoffrey Hinton. Cifar-10 (canadian institute for advanced research). 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 234, + 287, + 277 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 234, + 287, + 277 + ], + "spans": [ + { + "bbox": [ + 48, + 234, + 287, + 277 + ], + "type": "text", + "content": "[33] Alexander Kugele, Thomas Pfeil, Michael Pfeiffer, and Elisabetta Chicca. Efficient processing of spatio-temporal data streams with spiking neural networks. Frontiers in Neuroscience, 14:439, 05 2020. 8" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 280, + 287, + 323 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 280, + 287, + 323 + ], + "spans": [ + { + "bbox": [ + 48, + 280, + 287, + 323 + ], + "type": "text", + "content": "[34] Chankyu Lee, Syed Sarwar, Priyadarshini Panda, Gopalakrishnan Srinivasan, and Kaushik Roy. Enabling spike-based backpropagation for training deep neural network architectures. Frontiers in Neuroscience, 14:119, 02 2020. 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 326, + 287, + 357 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 326, + 287, + 357 + ], + "spans": [ + { + "bbox": [ + 48, + 326, + 287, + 357 + ], + "type": "text", + "content": "[35] Hongmin Li. Cifar10-dvs: An event-stream dataset for object classification. Frontiers in Neuroscience, 11, 05 2017. 6" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 360, + 287, + 403 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 360, + 287, + 403 + ], + "spans": [ + { + "bbox": [ + 48, + 360, + 287, + 403 + ], + "type": "text", + "content": "[36] Hao Li, Zheng Xu, Gavin Taylor, Christoph Studer, and Tom Goldstein. Visualizing the loss landscape of neural nets. Advances in neural information processing systems, 31, 2018. 5" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 406, + 287, + 437 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 406, + 287, + 437 + ], + "spans": [ + { + "bbox": [ + 48, + 406, + 287, + 437 + ], + "type": "text", + "content": "[37] Yuhang Li, Shikuang Deng, Xin Dong, and et al. A free lunch from ann: Towards efficient, accurate spiking neural networks calibration. In ICML, 2021. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 441, + 287, + 495 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 441, + 287, + 495 + ], + "spans": [ + { + "bbox": [ + 48, + 441, + 287, + 495 + ], + "type": "text", + "content": "[38] Yuhang Li, Yufei Guo, Shanghang Zhang, Shikuang Deng, Yongqing Hai, and Shi Gu. Differentiable spike: Rethinking gradient-descent for training spiking neural networks. Advances in Neural Information Processing Systems, 34, 2021. 2, 4, 6, 7" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 498, + 287, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 498, + 287, + 529 + ], + "spans": [ + { + "bbox": [ + 48, + 498, + 287, + 529 + ], + "type": "text", + "content": "[39] S. A. Lobov and et al. Spatial properties of stdp in a spiking neural network enable controlling a mobile robot. Frontiers in Neuroscience, 2020. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 533, + 287, + 564 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 533, + 287, + 564 + ], + "spans": [ + { + "bbox": [ + 48, + 533, + 287, + 564 + ], + "type": "text", + "content": "[40] Ping Luo, Jiamin Ren, Zhanglin Peng, Ruimao Zhang, and Jingyu Li. Differentiable learning-to-normalize via switchable normalization, 2019. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 567, + 287, + 610 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 567, + 287, + 610 + ], + "spans": [ + { + "bbox": [ + 48, + 567, + 287, + 610 + ], + "type": "text", + "content": "[41] Mitchell A Nahmias, Bhavin J Shastri, Alexander N Tait, and Paul R Prucnal. A leaky integrate-and-fire laser neuron for ultrafast cognitive computing. IEEE journal of selected topics in quantum electronics, 19(5):1-12, 2013. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 613, + 287, + 677 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 613, + 287, + 677 + ], + "spans": [ + { + "bbox": [ + 48, + 613, + 287, + 677 + ], + "type": "text", + "content": "[42] Jing Pei, Lei Deng, Sen Song, Mingguo Zhao, Youhui Zhang, Shuang Wu, Guanrui Wang, Zhe Zou, Zhenzhi Wu, Wei He, Feng Chen, Ning Deng, Si Wu, Yu Wang, Yujie Wu, Zheyu Yang, Cheng Ma, Guoqi Li, Wentao Han, and L.P. Shi. Towards artificial general intelligence with hybrid tianjic chip architecture. Nature, 572:106, 08 2019. 1" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 680, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 680, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 680, + 287, + 712 + ], + "type": "text", + "content": "[43] Peter, U., Diehl, Matthew, and Cook. Unsupervised learning of digit recognition using spike-timing-dependent plasticity. Frontiers in Computational Neuroscience, 9:99, 2015. 2" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 31, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "text", + "content": "[44] Nitin Rathi and Kaushik Roy. DIET-SNN: direct input encoding with leakage and threshold optimization in deep spiking neural networks. CoRR, abs/2008.03658, 2020. 5, 6" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 107, + 545, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 149 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 149 + ], + "type": "text", + "content": "[45] Nitin Rathi, Gopalakrishnan Srinivasan, Priyadarshini Panda, and Kaushik Roy. Enabling deep spiking neural networks with hybrid conversion and spike timing dependent backpropagation. 05 2020. 6, 7" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 152, + 545, + 193 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 193 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 193 + ], + "type": "text", + "content": "[46] Abhronil Sengupta, Yuting Ye, Robert Wang, Chiao Liu, and Kaushik Roy. Going deeper in spiking neural networks: Vgg and residual architectures. Frontiers in Neuroscience, 13, 02 2018. 2, 5, 6, 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 195, + 545, + 248 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 195, + 545, + 248 + ], + "spans": [ + { + "bbox": [ + 307, + 195, + 545, + 248 + ], + "type": "text", + "content": "[47] Jiangrong Shen, Qi Xu, Jian K Liu, Yueming Wang, Gang Pan, and Huajin Tang. Esl-snns: An evolutionary structure learning strategy for spiking neural networks. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 37, pages 86-93, 2023. 1" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 250, + 545, + 281 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 250, + 545, + 281 + ], + "spans": [ + { + "bbox": [ + 307, + 250, + 545, + 281 + ], + "type": "text", + "content": "[48] Dmitry Ulyanov, Andrea Vedaldi, and Victor Lempitsky. Instance normalization: The missing ingredient for fast stylization, 2017. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 283, + 545, + 348 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 283, + 545, + 348 + ], + "spans": [ + { + "bbox": [ + 307, + 283, + 545, + 348 + ], + "type": "text", + "content": "[49] Siqi Wang, Tee Hiang Cheng, and Meng-Hiot Lim. LTMD: Learning improvement of spiking neural networks with learnable thresholding neurons and moderate dropout. In Alice H. Oh, Alekh Agarwal, Danielle Belgrave, and Kyunghyun Cho, editors, Advances in Neural Information Processing Systems, 2022. 4" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 350, + 545, + 380 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 350, + 545, + 380 + ], + "spans": [ + { + "bbox": [ + 307, + 350, + 545, + 380 + ], + "type": "text", + "content": "[50] Yujie Wu, Lei Deng, and et al. Spatio-temporal backpropagation for training high-performance spiking neural networks. Frontiers in neuroscience, 2018. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 383, + 545, + 425 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 383, + 545, + 425 + ], + "spans": [ + { + "bbox": [ + 307, + 383, + 545, + 425 + ], + "type": "text", + "content": "[51] Yujie Wu, Lei Deng, Guoqi Li, Jun Zhu, Yuan Xie, and L.P. Shi. Direct training for spiking neural networks: Faster, larger, better. Proceedings of the AAAI Conference on Artificial Intelligence, 33:1311-1318, 07 2019. 1, 2, 4, 8" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 426, + 545, + 459 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 426, + 545, + 459 + ], + "spans": [ + { + "bbox": [ + 307, + 426, + 545, + 459 + ], + "type": "text", + "content": "[52] Yuxin Wu and Kaiming He. Group normalization. In Proceedings of the European conference on computer vision (ECCV), pages 3-19, 2018. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 460, + 545, + 514 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 460, + 545, + 514 + ], + "spans": [ + { + "bbox": [ + 307, + 460, + 545, + 514 + ], + "type": "text", + "content": "[53] Zhenzhi Wu, Hehui Zhang, Yihan Lin, Guoqi Li, Meng Wang, and Ye Tang. Liaf-net: Leaky integrate and analog fire network for lightweight and efficient spatiotemporal information processing. IEEE Transactions on Neural Networks and Learning Systems, 33(11):6249-6262, 2022. 8" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 515, + 545, + 547 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 515, + 545, + 547 + ], + "spans": [ + { + "bbox": [ + 307, + 515, + 545, + 547 + ], + "type": "text", + "content": "[54] Mingqing Xiao, Qingyan Meng, Zongpeng Zhang, Di He, and Zhouchen Lin. Online training through time for spiking neural networks. arXiv preprint arXiv:2210.04195, 2022. 7" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 548, + 545, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 548, + 545, + 602 + ], + "spans": [ + { + "bbox": [ + 307, + 548, + 545, + 602 + ], + "type": "text", + "content": "[55] Rong Xiao, Yu Wan, Baosong Yang, Haibo Zhang, Huajin Tang, Derek F Wong, and Boxing Chen. Towards energy-preserving natural language understanding with spiking neural networks. IEEE/ACM Transactions on Audio, Speech, and Language Processing, 31:439-447, 2022. 1" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 604, + 545, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 604, + 545, + 646 + ], + "spans": [ + { + "bbox": [ + 307, + 604, + 545, + 646 + ], + "type": "text", + "content": "[56] Qi Xu, Yaxin Li, Xuanye Fang, Jiangrong Shen, Jian K Liu, Huajin Tang, and Gang Pan. Biologically inspired structure learning with reverse knowledge distillation for spiking neural networks. arXiv preprint arXiv:2304.09500, 2023. 1" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 647, + 545, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 647, + 545, + 690 + ], + "spans": [ + { + "bbox": [ + 307, + 647, + 545, + 690 + ], + "type": "text", + "content": "[57] Qi Xu, Yaxin Li, Jiangrong Shen, Jian K Liu, Huajin Tang, and Gang Pan. Constructing deep spiking neural networks from artificial neural networks with knowledge distillation. arXiv preprint arXiv:2304.05627, 2023. 1" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 692, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 692, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 692, + 545, + 712 + ], + "type": "text", + "content": "[58] Qi Xu, Yaxin Li, Jiangrong Shen, Pingping Zhang, Jian K Liu, Huajin Tang, and Gang Pan. Hierarchical spiking-based" + } + ] + } + ], + "index": 30 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19429" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 262 + ], + "type": "list", + "angle": 0, + "index": 5, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 106 + ], + "type": "text", + "content": "model for efficient image classification with enhanced feature extraction and encoding. IEEE Transactions on Neural Networks and Learning Systems, 2022. 1" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 287, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 287, + 150 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 287, + 150 + ], + "type": "text", + "content": "[59] Qi Xu, Jiangrong Shen, Xuming Ran, Huajin Tang, Gang Pan, and Jian K Liu. Robust transcoding sensory information with neural spikes. IEEE Transactions on Neural Networks and Learning Systems, 33(5):1935-1946, 2021. 1" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 152, + 287, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 152, + 287, + 194 + ], + "spans": [ + { + "bbox": [ + 48, + 152, + 287, + 194 + ], + "type": "text", + "content": "[60] Xingting Yao, Fanrong Li, Zitao Mo, and Jian Cheng. Glif: A unified gated leaky integrate-and-fire neuron for spiking neural networks. arXiv preprint arXiv:2210.13768, 2022. 6, 7" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 197, + 287, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 197, + 287, + 228 + ], + "spans": [ + { + "bbox": [ + 48, + 197, + 287, + 228 + ], + "type": "text", + "content": "[61] Wenrui Zhang and Peng Li. Temporal spike sequence learning via backpropagation for deep spiking neural networks. 02 2020. 7" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 230, + 287, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 230, + 287, + 262 + ], + "spans": [ + { + "bbox": [ + 48, + 230, + 287, + 262 + ], + "type": "text", + "content": "[62] Hanle Zheng, Yujie Wu, Lei Deng, Yifan Hu, and Guoqi Li. Going deeper with directly-trained larger spiking neural networks. 10 2020. 1, 3, 6, 7, 8" + } + ] + } + ], + "index": 4 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19430" + } + ] + } + ], + "index": 6 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Memory-and-Anticipation Transformer for Online Action Understanding/a1b3a75e-11e3-4ea7-94a7-a5bef15574c1_content_list.json b/2023/Memory-and-Anticipation Transformer for Online Action Understanding/a1b3a75e-11e3-4ea7-94a7-a5bef15574c1_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..5e5f6e625d367366db52c88444bd778c6a577bfb --- /dev/null +++ b/2023/Memory-and-Anticipation Transformer for Online Action Understanding/a1b3a75e-11e3-4ea7-94a7-a5bef15574c1_content_list.json @@ -0,0 +1,1713 @@ +[ + { + "type": "text", + "text": "Memory-and-Anticipation Transformer for Online Action Understanding", + "text_level": 1, + "bbox": [ + 114, + 130, + 854, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Jiahao Wang $^{1*}$ Guo Chen $^{1,2*}$ Yifei Huang $^{2}$ Limin Wang $^{1,2}$ Tong Lu $^{1\\boxtimes}$ $^{1}$ State Key Laboratory for Novel Software Technology, Nanjing University \n $^{2}$ Shanghai AI Laboratory", + "bbox": [ + 169, + 179, + 799, + 234 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 258, + 268, + 336, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Most existing forecasting systems are memory-based methods, which attempt to mimic human forecasting ability by employing various memory mechanisms and have progressed in temporal modeling for memory dependency. Nevertheless, an obvious weakness of this paradigm is that it can only model limited historical dependence and can not transcend the past. In this paper, we rethink the temporal dependence of event evolution and propose a novel memory-anticipation-based paradigm to model an entire temporal structure, including the past, present, and future. Based on this idea, we present Memory-and-Anticipation Transformer (MAT), a memory-anticipation-based approach, to address the online action detection and anticipation tasks. In addition, owing to the inherent superiority of MAT, it can process online action detection and anticipation tasks in a unified manner. The proposed MAT model is tested on four challenging benchmarks TVSeries, THUMOS'14, HDD, and EPIC-Kitchens-100, for online action detection and anticipation tasks, and it significantly outperforms all existing methods. Code is available at https://github.com/Echo0125/Memory-and-Anticipation-Transformer.", + "bbox": [ + 76, + 300, + 473, + 632 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 664, + 209, + 680 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Online anticipation [32] or detection [10] in computer vision attempt to perceive future or present states from a historical perspective. They are the crucial factors of AI systems that engage with complex real environments and interact with other agents, e.g. wearable devices [46], human-robot interaction systems [33], and autonomous vehicles [62].", + "bbox": [ + 75, + 691, + 468, + 797 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Human beings frequently imagine future events based on past experiences. Similarly, anticipating future events inherently requires modeling past actions or the progression of events to predict what will happen next. To bridge the gap with human forecasting ability, current systems", + "bbox": [ + 75, + 797, + 470, + 875 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/fda5038fd67c3a9bd266960e1d244aff40dc654540c84fad370ae12ca4e16ffa.jpg", + "image_caption": [ + "Figure 1: Examples for the forward influence of memory and backward constraint of anticipation. (a) An athlete prepares to start, starts to run, and then jumps to form the result of completing a high jump; (b) The goals of a camera wearer for cutting a tomato dictate the sequence of actions he will perform: hold the knife, get ready to cut, etc.; (c) Compared with the memory-based method, the memory-anticipation-based method is able to establish circular dependencies between memory and future." + ], + "image_footnote": [], + "bbox": [ + 503, + 267, + 890, + 498 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "strive to mimic this cognitive ability by employing different memory mechanisms [58, 26, 7, 67, 44, 17]. Previous research [14, 44] demonstrated that modeling long temporal context is crucial for accurate anticipation. LSTR [58] further decomposes the memory encoder into long and short-term stages for online action detection and anticipation, allowing for the extraction of more representative memory features. Similarly, research efforts such as [67, 7, 27] have also illustrated improvements based on this principle.", + "bbox": [ + 496, + 641, + 890, + 777 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "However, despite various memory-based approaches, memory is not the only driver of present or future action. The synchronization between shot transitions and the evolution of actor behavior appears to cohere with the beliefs and wills of the event weavers, be they actors or camerewearers. In (a) and (b) of Fig 1, we use the examples of high jumping and cooking to show the forward influence of memory and backward constraint of anticipation.", + "bbox": [ + 496, + 779, + 892, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "* Equal contribution, ⌒ Corresponding author (lutong@nju.edu.cn)", + "bbox": [ + 99, + 886, + 460, + 900 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "13824", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Upon closer examination of both examples, it has been observed that future-oriented thoughts may impact action and memory, which seems modulated by the encoding of new information [43, 25]. Additionally, anticipation may change as ongoing behavior progresses and memory is updated [41, 20]. This indicates that there exists a circular interdependence between anticipation and memory, constraining the evolution of behavior or events.", + "bbox": [ + 75, + 90, + 470, + 210 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Based on the preceding analysis, we reevaluate the temporal dependencies inherent in memory-based methods. In their preoccupation with the impact of memory on anticipation, these memory-based methods tend to overlook the inverse direction of impact, i.e., anticipation on memory. Consequently, historical representations are not adequately corrected, thereby risking impeding any attempts to transcend the past. Against this backdrop, we assert that a comprehensive temporal structure seamlessly integrates memory and anticipation is indispensable. In other words, a memory-anticipation-based method building circular dependencies between memory and anticipation, as shown in Fig 1(c), holds tremendous promise for enhancing cognitive inference capabilities and advanced understanding of AI systems about the present and future.", + "bbox": [ + 75, + 214, + 468, + 441 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To this end, we propose Memory-and-Anticipation Transformer (MAT), a novel memory-anticipation-based approach that fully models the complete temporal context, including history, present, and future. A Progressive Memory Encoder is designed to provide a more precise history summary by compressing long- and short-term memory in a segment-based fashion. Meanwhile, we propose our key idea of modeling circular dependencies between memory and future, implemented as Memory-Anticipation Circular Decoder. It first learns latent future features in a supervised manner, then updates iteratively the enhanced short-term memory and the latent future features by performing Conditional circular Interaction between them. Among them, multiple interaction processes capture the circular dependency and supervise the output to maintain stable features with real semantics.", + "bbox": [ + 75, + 443, + 468, + 684 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Remarkably, owing to the inherent superiority of our model design, we are able to adapt both tasks, i.e., online action detection and anticipation, in a unified manner, spanning the training and online inference stages. For any given dataset, the MAT model obviates the need for separate training or testing for each task. Rather, a single training process is enough, and during inference, the corresponding token for each task can be extracted effortlessly.", + "bbox": [ + 75, + 686, + 468, + 808 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In summary, our contributions are 1). We rethink the temporal dependence of event evolution and propose a memory-anticipation-based paradigm for the circular interaction of memory and anticipation, introducing the concept of memory and future circular dependence. 2). We propose a unified architecture Memory-Anticipation Transformer", + "bbox": [ + 75, + 810, + 470, + 902 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "(MAT) that simultaneously processes online action detection and anticipation, showing effective performance. 3). MAT significantly outperforms all existing methods on four challenging benchmarks for online action detection and anticipation tasks, i.e., TVSeries [10], THUMOS'14 [30], HDD [42] and EPIC-Kitchens-100 [9].", + "bbox": [ + 496, + 90, + 890, + 183 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 195, + 640, + 210 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Online Action Detection and Anticipation. Online action detection [10] aims to predict the action as it happens without accessing the future. Previous methods [57, 12, 16, 61, 54, 58, 7, 67, 4] for online action detection include recurrent networks, reinforcement learning, and, more recently, transformers. [15] uses a reinforced network to encourage making great decisions as early as possible. [57] adopts RNN to generate future predictions to improve online action detection. [58] proposes a transformer to scale the history spanning a longer duration. The target of action anticipation [9, 14, 17, 56] is predicting what actions will occur after a certain time. RULSTM [14] explores action anticipation and proposes an LSTM-based network to solve this problem. AVT [17] proposed an end-to-end attention-based model for anticipative video modeling and learns feature representations by self-supervised methods.", + "bbox": [ + 496, + 220, + 890, + 462 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Online action detection and anticipation share two key characteristics: the inability to perceive future representations, with information derived solely from historical context, and the goal of predicting actions after a certain time. Previous research has typically studied the model for each task in isolation [61, 7] or trained and tested them separately [58, 67], ignoring the potential benefits of leveraging their shared characteristics. We propose a novel unified framework, named MAT, to address this limitation, which allows us to train or infer both tasks simultaneously.", + "bbox": [ + 496, + 463, + 890, + 613 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Transformer for Video Understanding. Transformers have proven successful in natural language processing [49], and researchers have shown increasing interest in its application to vision tasks [11, 48, 40, 53, 18, 37]. Several methods have been proposed to use transformers for temporal modeling in video-related tasks [1, 2, 6, 28, 35, 36, 39, 52, 55, 65]. Timesformer [3] proposes divided attention to capture spatial and temporal information for action recognition separately. MViT [13] builds a feature hierarchy by progressively expanding channel capacity and reducing video spatial-temporal resolution. Actionformer [63] adopts the transformer architecture with local attention for temporal action localization. TubeDETR [60] tackles video grounding with an encoder-decoder transformer-based architecture to efficiently encode spatial and multi-modal interactions. Our MAT model is also built upon the transformer, utilizing its encoder and decoder architectures. We meticulously integrate the transformer blocks to implement our memory encoder and memory-anticipation circular decoder.", + "bbox": [ + 496, + 614, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "13825", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/84096c7762465264f596457b38a592b26977a4f3d7eeb453f581268434854c36.jpg", + "image_caption": [ + "Progressive Memory Encoder", + "Memory-Anticipation Circular Decoder", + "Figure 2: MAT architecture. We first divide the temporal sequence into long-term and short-term memories. In Progressive Memory Encoder, long-term memory queries $\\mathbf{Q}_L$ progressively map the long-term to an abstract representation and be fed to the transformer decoder block to enhance the short-term memory. Then the Memory-Anticipation Circular Decoder utilizes learnable queries $\\mathbf{Q}_F$ and $\\mathbf{Q}_F'$ to perceive the future context and circularly updates the historical and future representation. Finally, a weight-shared classifier is adopted to output the classification scores of short-term and future for online action detection and anticipation." + ], + "image_footnote": [], + "bbox": [ + 81, + 103, + 893, + 250 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Problem Setup", + "text_level": 1, + "bbox": [ + 76, + 348, + 227, + 366 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Online action anticipation and detection share a similar goal of predicting actions in untrimmed video sequences. In the former, we aim to forecast actions after a time gap $\\tau$ , as defined in [9], while in the latter, we predict the action under $\\tau = 0$ . Both tasks require classifying actions without access to future information during inference. We represent the input video as $\\mathbf{V} = \\{v_t\\}_{t = -T + 1}^0$ , and our objective is to predict the action category $\\tilde{y}_{\\tau} \\in \\{0,1,2,\\dots,C\\}$ occurs after a specified time gap $\\tau$ in the future. Here, $C$ represents the total number of action categories, and label 0 denotes the background category.", + "bbox": [ + 75, + 375, + 472, + 541 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4. Memory-and-Anticipation Transformer", + "text_level": 1, + "bbox": [ + 76, + 554, + 434, + 571 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We now describe Memory-and-Anticipation Transformer (MAT) model architecture, as illustrated in Fig 2. It processes the memory cached in runtime to predict current or future actions. We adopt the encoder-decoder architecture to implement the model. The Progressive Memory Encoder is proposed to improve the quality of compressing long-term memory and enhancing short-term memory, which has a fundamental impact on anticipation and detection. MAT also employs our presented key component Memory-Anticipation Circular Decoder that generates the latent anticipation feature and conducts interaction between memory and anticipation in an iterative loop. We now introduce each model component in detail, followed by the training, online inference, and implementation details.", + "bbox": [ + 75, + 580, + 468, + 791 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4.1. Progressive Memory Encoder", + "text_level": 1, + "bbox": [ + 76, + 801, + 341, + 816 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We use video feature $\\mathbf{F} = \\{f_t\\}_{t = -T + 1}^0\\in \\mathbb{R}^{T\\times D}$ generated by a pretrained feature extractor as the input to our model, where $D$ and $T$ are the dimension and length of the feature sequence, respectively. To better handle the long memory, following [58], we divide the feature sequence into", + "bbox": [ + 75, + 823, + 470, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "two consecutive memories. The first is the short-term memory that stores only a handful of recently occurred frames. It stores the feature vectors as $\\mathbf{M}_S = \\{f_t\\}_{t = -m_S + 1}^0$ , where $m_{S}$ denotes the length. The other, named long-term memory, contains the feature that is far away from the current time, which is defined as $\\mathbf{M}_L = \\{f_t\\}_{t = -T + 1}^{-m_S}$ . We set $m_{L}$ to be the length of the long-term memory, which is much longer than the short-term memory.", + "bbox": [ + 496, + 349, + 890, + 470 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In practice, Progressive Memory Encoder progressively encodes long- and short-term memories. It first compresses the long-term memory to an abstract representation and injects them into the short-term memory. Differing with previous works [58, 67] that separately tackle the long- and short-term memories by one long-term encoder and one short-term decoder, we integrate these two works into a single encoder architecture. It is due to our encoded short-term memory being served for decoders and not as the final output. In our experiments, we observe that the design of the memory encoder is crucial for model performance. Therefore, different with [58, 67], we introduce a novel long-term memory compression method to improve the quality of memory encoding.", + "bbox": [ + 496, + 473, + 892, + 684 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Segment-based Long-term Memory Compression. LSTR [58] adopts a two-stage compression technique to project the long-term memory to a fixed-length latent embedding. It implements a function similar to the bottleneck layer [22]. Long-term memory, however, represents a long token sequence that often carries much noise. It is problematic to generate attention weights while crossattention queries too many tokens with mixed noise. We propose Segment-based Long-term Memory Compression to alleviate the issue, as shown in Fig 3. Concretely, we first divide $\\mathbf{M}_L$ into $N_{s}$ non-overlapping memory segments $\\mathbf{S} = \\{\\mathbf{s}_i\\}_{i = 1}^{N_s}$ of length $\\frac{m_L}{N_s}$ . We then employ $N_{L}$ learnable tokens $\\mathbf{Q}_L\\in \\mathbb{R}^{N_L\\times D}$ as the long-term memory queries and a weight-shared transformer decoder block to query", + "bbox": [ + 496, + 686, + 893, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "13826", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "each segment. $\\mathbf{S}$ will be transformed to $N_{s}$ segment-level abstract feature $\\mathbf{F} = \\{\\mathbf{f}_i\\}_{i = 1}^{N_s}$ , where $\\mathbf{f}_i\\in \\mathbb{R}^{N_L\\times D}$ . We average pool each $\\mathbf{f}_i$ to one vector $\\mathbb{R}^D$ and concatenate them to form the long-term compressed segmented memory $\\mathbf{M}_L^s\\in \\mathbb{R}^{N_s\\times D}$ . At last, we feed them into two transformer encoder blocks to obtain the final compressed longterm memory $\\widehat{\\mathbf{M}}_L\\in \\mathbb{R}^{N_s\\times D}$ .", + "bbox": [ + 75, + 90, + 468, + 196 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Short-term Memory Enhancement. As short-term memory $\\mathbf{M}_S = \\{f_t\\}_{t = -m_S + 1}^0$ contains crucial trends for accurately predicting the current or upcoming activities, we leverage short-term memory as the query to retrieve relevant context from the compressed long-term memory. As illustrated in Fig 2, we employ a transformer causal decoder block to aggregate compressed long-term memory $\\widehat{\\mathbf{M}}_L$ into short-term memory. The enhanced short-term memory $\\widehat{\\mathbf{M}}_S$ is then used to identify actions at each timestep, constituting a sequence of previously occurring actions and predicting future states and actions. We use frame-level action labels to supervise the dense classification task, encouraging the model to produce a clear sequence of historical behavior.", + "bbox": [ + 75, + 198, + 470, + 398 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.2. Memory-Anticipation Circular Decoder", + "text_level": 1, + "bbox": [ + 76, + 404, + 419, + 420 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To implement our key idea that considers the co-reaction between anticipation and memory, we carefully design Memory-Anticipation Circular Decoder that circularly performs interaction between them. It first generates the latent anticipation that is a prerequisite for memory-anticipation interaction. Then, Conditional Circular Interaction will generate new memories and anticipation conditioned on old ones iteratively. Finally, a weight-shared classification head will supervise the generated memories and anticipation.", + "bbox": [ + 75, + 428, + 468, + 563 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Latent Anticipation Generation. Initially, we do not have an anticipation state. Therefore, we must first generate a latent anticipation feature, i.e., a future representation containing abstract information derived from known memory. Given the compressed long-term memory $\\widehat{\\mathbf{M}}_L$ and short-term memory $\\widehat{\\mathbf{M}}_S$ , we first concatenate them to form the entire memory $\\mathbf{M}_E = [\\widehat{\\mathbf{M}}_L, \\widehat{\\mathbf{M}}_S]$ , where $[\\cdot, \\cdot]$ is the concatenating operation along the temporal dimension. Then, we use $N_F$ future queries $\\mathbf{Q}_F \\in \\mathbb{R}^{N_F \\times D}$ and a transformer decoder block to query $\\mathbf{M}_E$ . The updated future queries are represented as the latent anticipation features $\\mathbf{F}_A \\in \\mathbb{R}^{N_F \\times D}$ at the current state. We use future information, e.g., future video features and future action labels, to supervise $\\mathbf{F}_A$ . In practice, we use information from the next $T_F$ seconds. Since $\\mathbf{F}_A$ is only used to describe the latent future states, too large future embeddings may overfit the anticipation representation. We set $N_F$ to be smaller than the length of the used future information sequence. Then we use bilinear interpolation to upsample it to align for point-to-point supervision. Note that although we use future information here, this does not lead to an information leak. The model will generate preliminary anticipation", + "bbox": [ + 75, + 564, + 470, + 901 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/cf0bbbf71d6b4c46b1bd735c217ba1258943f1d92de9b2a59da2728a1ae4d20f.jpg", + "image_caption": [ + "Figure 3: Segment-based Long-term Memory Compression. For example, given $m_{L} = 9$ , $N_{s} = 3$ , the process is shown above. We can finally obtain compressed features $\\widehat{M}_L$ of length 3." + ], + "image_footnote": [], + "bbox": [ + 504, + 90, + 890, + 252 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "in the inference phase and not use future labels or features.", + "bbox": [ + 498, + 335, + 887, + 349 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Conditional Circular Interaction. So far, we have generated long-term memory $\\widehat{\\mathbf{M}}_L$ , short-term memory $\\widehat{\\mathbf{M}}_S$ and latent anticipation features $\\mathbf{F}_A$ . The memories, however, are limited to the past and can not go beyond history. We now describe how Conditional Circular Interaction works. For brevity, we detail how memory and anticipation interact with each other one time.", + "bbox": [ + 498, + 349, + 890, + 455 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "As shown in Fig 4, we first concatenate $\\widehat{\\mathbf{M}}_L$ , $\\widehat{\\mathbf{M}}_S$ and $\\mathbf{F}_A$ to form the entire feature $\\mathbf{F}_E = [\\widehat{\\mathbf{M}}_L, \\widehat{\\mathbf{M}}_S, \\mathbf{F}_A]$ . Then, $\\mathbf{F}_E$ and $\\widehat{\\mathbf{M}}_S$ are feed into a transformer decoder block:", + "bbox": [ + 498, + 455, + 890, + 506 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\widehat {\\mathbf {M}} _ {S} ^ {\\prime} = \\operatorname {C r o s s A t t n} \\left(\\widehat {\\mathbf {M}} _ {S}, \\mathbf {F} _ {E}, \\mathbf {F} _ {E}\\right), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 581, + 517, + 890, + 536 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathrm{CrossAttn}(Q,K,V)$ is the cross-attention layer in the transformer decoder block. The updated short-term memory is represented as $\\widehat{\\mathbf{M}}_S^{\\prime}$ . Since $\\mathbf{F}_E$ contains memories and anticipation, $\\widehat{\\mathbf{M}}_S$ as a query condition dynamically extracts new semantics mixed with memories and anticipation from three representations. Next, we re-concatenate $\\widehat{\\mathbf{M}}_L$ , $\\widehat{\\mathbf{M}}_S^{\\prime}$ and $\\mathbf{F}_A$ to generate the new entire feature $\\mathbf{F}_E^{\\prime} = [\\widehat{\\mathbf{M}}_L,\\widehat{\\mathbf{M}}_S^{\\prime},\\mathbf{F}_A]$ . Another transformer decoder block is used to query $\\mathbf{F}_E^{\\prime}$ , with $\\mathbf{F}_A$ as the query condition:", + "bbox": [ + 498, + 547, + 890, + 691 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {F} _ {A} ^ {\\prime} = \\operatorname {C r o s s A t t n} \\left(\\mathbf {F} _ {A}, \\mathbf {F} _ {E} ^ {\\prime}, \\mathbf {F} _ {E} ^ {\\prime}\\right), \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 586, + 703, + 890, + 720 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbf{F}_A^\\prime$ is the resulting anticipation features. After that, $\\mathbf{F}_A^\\prime$ is injected with the higher-order inferred semantics brought about by the interaction between memory and anticipation.", + "bbox": [ + 498, + 732, + 890, + 792 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In the interaction process, the generated $\\widehat{\\mathbf{M}}_S^{\\prime}$ is both supervised like the above initial anticipation features. It should be noted that different from generating latent initial anticipation through fewer future queries, we find that using a new group of future queries $\\mathbf{Q}_F^{\\prime} \\in \\mathbb{R}^{N_F^{\\prime} \\times D}$ strictly aligned future information sequences of $T_{F}$ seconds in the first interaction process to replace the $\\mathbf{F}_A$ with $\\mathbf{Q}_F^{\\prime}$ , bring", + "bbox": [ + 496, + 792, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "13827", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/7fe50402cc49b9a7ca248989783fbd5f5eff4f00abb59eea7fef14c4a3887e7f.jpg", + "image_caption": [ + "Figure 4: Conditional circular interaction dynamically updates and re-constructs the context between memories and anticipation by aggregating different temporal information." + ], + "image_footnote": [], + "bbox": [ + 78, + 88, + 472, + 220 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "performance improvement. Thus, we point-to-point supervise the anticipation $\\mathbf{F}_A^\\prime$ generated by each interaction process. Meanwhile, this design is more natural to output the corresponding token according to the anticipation gap time. We circularly perform the interaction process $N_{t}$ times until saturation. The yielded $\\widehat{\\mathbf{M}}_S^{\\prime}$ and $\\mathbf{F}_A^\\prime$ in one interaction process become the new $\\widehat{\\mathbf{M}}_S$ and $\\mathbf{F}_A$ and are passed to the next interaction process.", + "bbox": [ + 75, + 296, + 468, + 421 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.3. Training", + "text_level": 1, + "bbox": [ + 76, + 429, + 181, + 445 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Our MAT model relies on action steps of short-term memory to predict the current or future action. These steps are utilized as auxiliary information to benefit action detection and anticipation. It is worth noting that since the MAT model regards online action detection and anticipation as the same tasks with different settings, we can define the loss function in a unified fashion.", + "bbox": [ + 75, + 452, + 468, + 556 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "For the $\\widehat{\\mathbf{M}}_S$ generated by the encoder, we feed it to a classifier to generate the action probabilities $\\widehat{\\mathbf{Y}}_S = \\{\\widehat{\\mathbf{y}}_S^i\\}_{i=1}^{m_S}$ . We then supervise the whole short-term memory using a cross-entropy loss with the labeled action, $\\{c_S^i\\}_{i=1}^{m_S}$ . Learned future features $\\mathbf{F}_A$ are fed into the same classifier to generate the probabilities $\\widehat{\\mathbf{Y}}_F = \\{\\widehat{\\mathbf{y}}_F^i\\}_{i=1}^{N_F}$ and we also adopt a cross-entropy loss with the target, $\\{c_F^i\\}_{i=1}^{m_S}$ :", + "bbox": [ + 76, + 558, + 470, + 666 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {S} ^ {0} = - \\sum_ {i = 1} ^ {m _ {S}} \\log \\widehat {\\mathbf {y}} _ {S} ^ {i} [ c _ {S} ^ {i} ], \\mathcal {L} _ {F} ^ {0} = - \\sum_ {i = 1} ^ {N _ {F}} \\log \\widehat {\\mathbf {y}} _ {F} ^ {i} [ c _ {F} ^ {i} ], \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 99, + 672, + 468, + 714 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathcal{L}_S^0$ and $\\mathcal{L}_F^0$ are the loss function of encoded shortterm memory and initial anticipation features, respectively. As the conditional circular interaction is conducted $N_{t}$ times, we use $\\mathcal{L}_S^i$ and $\\mathcal{L}_F^i$ to represent the loss of memory and anticipation in each interaction process, where $1\\leq i\\leq N_{t}$ . Their calculation is similar to $\\mathcal{L}_S^0$ and $\\mathcal{L}_F^0$ . The final training loss is formulated by:", + "bbox": [ + 75, + 720, + 468, + 828 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} = \\sum_ {i = 0} ^ {N _ {t}} \\lambda_ {s} ^ {i} \\cdot \\mathcal {L} _ {S} ^ {i} + \\lambda_ {f} \\sum_ {i = 0} ^ {N _ {t}} \\mathcal {L} _ {F} ^ {i}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 168, + 835, + 468, + 878 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\lambda_s^i$ and $\\lambda_{f}$ are the balance coefficients.", + "bbox": [ + 76, + 885, + 377, + 901 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.4. Online Inference", + "text_level": 1, + "bbox": [ + 500, + 90, + 666, + 104 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The existing works [57, 61, 58, 67, 17] test each task independently. Thanks to the design of the unified framework, MAT simultaneously infers online action detection and anticipation tasks on one streaming video. It uses the output $\\widehat{\\mathbf{M}}_S$ and $\\mathbf{F}_A$ produced by the last interaction as results of online action detection and anticipation, respectively. We take out the last token of $\\widehat{\\mathbf{M}}_S$ for online action detection. For action anticipation, according to gap time $\\tau$ , we take out the corresponding token from $\\mathbf{F}_A$ for forecasting.", + "bbox": [ + 496, + 114, + 893, + 255 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 500, + 268, + 633, + 286 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.1. Dataset and Metrics", + "text_level": 1, + "bbox": [ + 500, + 294, + 691, + 309 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Dataset. We test on three online action detection datasets. THUMOS'14 [30] consists of over 20 hours of sports video annotated with 20 actions. TVSeries [10] includes 27 episodes of 6 popular TV series, about 150 minutes each and 16 hours total. HDD [42] is a largescale human driving video dataset comprising 104 hours of untrimmed videos and 11 action categories. Furthermore, we evaluate on EpicKitchens-100 [9] that contains 100 hours of egocentric videos with at least 90K action segments and whose narrations are mapped to 97 verb classes and 300 noun classes.", + "bbox": [ + 496, + 319, + 890, + 484 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Evaluation Metrics. For online action detection, following previous works [10, 34, 54, 58, 61], we use per-frame mean Average Precision (mAP) on THUMOS'14 and HDD, and per-frame mean calibrated Average Precision (mcAP) [10] on TVSeries. For action anticipation, we employ Top-5 Verb/Noun/Action Recall to measure the performance with an anticipation period $\\tau = 1s$ [9].", + "bbox": [ + 496, + 486, + 890, + 592 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.2. Implementation details", + "text_level": 1, + "bbox": [ + 500, + 604, + 714, + 619 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Following prior works [57, 58, 67], we conduct our experiments on pre-extracted features. For TVSeries and THUMOS'14, we first resample the videos at 24 FPS and then extract the frames at 4 FPS for training and validation. We adopt a two-stream network [50] to extract feature. We use off-the-shell checkpoint released by mmentation2 [8] that pretrained on ActivityNet v1.3 [23] and Kinetics [31] to extract frame-level RGB and optical features. On EK100, following [14], we resample the videos at 30 FPS and then fine-tune the two-stream TSN on the classification task.", + "bbox": [ + 496, + 628, + 890, + 777 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Memory Dropping. Despite the promising capabilities of the dense attention mechanism, capturing long-range dependencies remains a challenge. However, relying on the dense attention mechanism may lead to sub-optimization of the network, resulting in a locally optimal solution. We seek to explore memory-dropping strategies for implementing sparse attention during training. We experiment with various approaches, including dropout [24], top-k selec", + "bbox": [ + 496, + 779, + 890, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "13828", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/2eec5bbb8d04abe7dc692c94d1535d6dc66a71ae20010a19f0667e167326fc95.jpg", + "table_caption": [], + "table_footnote": [ + "(a) Segment number." + ], + "table_body": "
NsmAP
[58]69.6
269.8
470.2
870.4
1270.1
", + "bbox": [ + 86, + 87, + 189, + 178 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/7f8883c81dba5413d18f759fac6a78bc28b93ff9f5348e6133be46a76ee79937.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
renewalmAP
070.0
170.4
269.7
", + "bbox": [ + 202, + 88, + 321, + 150 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/aaf378abb78735e344ea8d7df4f7133ad5aed16ccedc375dbd8e8246dbbb8904.jpg", + "table_caption": [], + "table_footnote": [ + "(b) Future queries renewing." + ], + "table_body": "
deepsupervisionmAP
-cls69.9
✓feat69.6
✓cls70.4
✓feat + cls70.2
", + "bbox": [ + 333, + 88, + 506, + 164 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/dd312d13e6088ea4305c16d51343d8e61e8c63a2ea15b9fd001bdbfaa2b67dba.jpg", + "table_caption": [], + "table_footnote": [ + "(c) Future supervision." + ], + "table_body": "
shortfuturemAP
unshared69.6
separately shared70.1
full shared70.4
", + "bbox": [ + 519, + 88, + 684, + 152 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/a361fde626e4c8bcf28a059a31732d1711bf6283a80b550749b15198b6b75a73.jpg", + "table_caption": [], + "table_footnote": [ + "(d) Shared classifier.", + "(e) MixClip+." + ], + "table_body": "
longshortVNA
--32.136.118.1
MC-32.936.918.4
MCMC31.037.418.5
MCMC+35.038.819.5
MC+MC+31.636.818.4
", + "bbox": [ + 694, + 88, + 887, + 178 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/d38deab0355a795f5ad40b3abe6a4e232b2984ce14234042c691ee63227ff13d.jpg", + "table_caption": [ + "Table 1: Ablation Experiments. We conduct detailed ablation on (a): Segment number, (b): Future queries renewing, (c): Future supervision, (d): Shared classifier, and (e): MixClip+. The gray rows denote default choices.", + "long short future interaction $N_{t}$ detection anticipation" + ], + "table_footnote": [], + "table_body": "
(a)--67.6+0.053.7+0.0
(b)✓CA168.3+0.754.7+1.0
(c)✓✓CA168.9+1.355.3+1.6
(d)✓✓CA168.6+1.055.8+2.1
(e)✓✓CA169.2+1.656.1+2.4
(f)✓✓✓Avg&Cat168.3+0.755.3+1.6
(g)✓✓✓CA169.9+2.356.6+2.9
(h)✓✓✓CA270.4+2.957.3+3.6
(i)✓✓✓CA370.2+2.657.1+3.4
", + "bbox": [ + 78, + 291, + 468, + 422 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2: Ablation study on the information stream, interaction method, and times for Conditional Circular Interaction. The shallow gray row denotes the baseline setting without any interaction.", + "bbox": [ + 75, + 431, + 468, + 474 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "tion [51], and token dropping [21]. We compare these strategies, recorded in the supplementary material, and find that the top-k selection yields the best performance.", + "bbox": [ + 75, + 489, + 468, + 535 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "MixClip+. TesTra [67] proposed an augmentation technique called MixClip to solve over-fitting caused by large long-term memory. Unlike long-term memory which presents an abstract concept, short-term memory provides a continuous motion trend, often playing a decisive role in anticipation. It leads to the fact that MixClip damages the continuity of motion, thereby, does not apply to short-term memory. We propose MixClip+ to solve the issue.", + "bbox": [ + 75, + 536, + 468, + 656 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In addition to mixing augmentation for long-term memory, we mix each feature token of short-term memory with a random clip from different videos. To maintain the continuity of short-term memory, we adopt soft fusion with hyperparameter $\\alpha = 0.25$ to mix features and the corresponding labels, similar to Mixup [64]. Due to space limitations, we will describe this part in the supplementary material.", + "bbox": [ + 75, + 657, + 468, + 762 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.3. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 771, + 230, + 787 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Now we analyze the MAT model, using the two-stream features pretrained on ActivityNet v1.3 and THUMOS'14 test set as the test bed. Furthermore, we also study the contribution of the proposed MixClip+ on EPIC-Kitchens-100.", + "bbox": [ + 75, + 794, + 468, + 854 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Segment Number. We evaluate the effect of segment number $N_{s}$ for long-term memory compression in Table 1a. We find even a small $N_{s}$ can improve performance, com", + "bbox": [ + 75, + 854, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/ffbb725d7783c022603e6a70b4e982b6c1d6ed63f69633601c8feb82760f765a.jpg", + "image_caption": [ + "Figure 5: Generating latent anticipation with different anticipation length $T_{F}$ and numbers of learnable tokens $N_{F}$ ." + ], + "image_footnote": [], + "bbox": [ + 516, + 277, + 877, + 429 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "pared with two-stage compression [58]. However, too many segments result in too little information within each segment to effectively capture temporal dependency. We use $N_{s} = 8$ as the default in the following ablation experiments.", + "bbox": [ + 498, + 489, + 890, + 549 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Query Number and Anticipation Length. Fig 5 compares generating latent anticipation using $N_{F}$ learnable tokens with different anticipation lengths $T_{F}$ . The experimental results indicate that, for $T_{F} \\leq 4$ , a larger $N_{F}$ yields superior results owing to strongly correlated semantics of short-term memory and short-term anticipation thus, the model can benefit from more tokens. We observe that $N_{F} = 8,16,32$ exhibits a similar trend in the accuracy curve, with the model achieving optimal performance with $N_{F} = 32$ . This suggests that long-term anticipation is more adaptable for sparse tokens. The observations imply that anticipation is also suitable for long- and short-term modeling.", + "bbox": [ + 496, + 551, + 892, + 733 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Future Queries Renewal. As Section 4.2 outlines, renewing future queries before the initial interaction improves performance. In Table 1b, we compare different renewing times (\"0\" denotes no renewal and utilizes $F_{A}$ ). A plausible explanation is that, in the first interaction process, the interaction from anticipation to memory adjusts the old memory, causing its domain to shift largely, which leads to insufficient interaction from the new memory to the initial anticipation feature.", + "bbox": [ + 496, + 733, + 890, + 868 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Future Supervision. In addition, we carry out diverse experiments to determine the optimal choice of future su", + "bbox": [ + 500, + 869, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "13829", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/d3264aa79738dd5262425a3599da896fcb0ec00ebdbbf5f6a452e28b0b4cf3cc.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodModalityInitOverallUnseenTail
VerbNounActionVerbNounActionVerbNounAction
RULSTM [14]RGBIN-1K27.529.013.329.823.813.119.921.410.6
AVT [17]IN-1K27.230.713.6------
AVT [17]IN-21K30.231.714.9------
DCR [59]IN-1K31.031.114.6------
TeSTra [67]IN-1K26.836.217.027.130.113.319.328.613.7
MAT (Ours)IN-1K32.739.718.831.732.112.725.732.416.0
RULSTM [14]RGB + OF + OBJIN-1K27.830.814.028.827.214.219.822.011.1
TempAgg [44]IN-1K23.231.414.728.026.214.514.522.514.8
AVT+ [17]IN-1K25.531.814.825.523.611.518.525.812.6
AVT+ [17]IN-21K28.232.015.929.526.012.823.229.214.1
TeSTra [67]RGB + OFIN-1K30.835.817.629.626.012.823.229.214.2
MAT (Ours)IN-1K35.038.819.532.530.313.828.733.116.9
", + "bbox": [ + 78, + 88, + 901, + 299 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/fd1b601f950f08e55a4237abd873982195f1d4bec7ebd980c122d3ffd62ff290.jpg", + "table_caption": [ + "Table 3: Comparison to prior work on EPIC-Kitchens-100 Action Anticipation [9]. Accuracy measured by class-mean recall@5(%) following the standard protocol." + ], + "table_footnote": [], + "table_body": "
ModalityEncoderInitFTOverallUnseenTail
RGBTSNIN-1K✓18.812.716.0
RGB + OFTSNIN-1K✓19.513.816.9
RGBViT-LK40019.116.216.1
RGB (V)ViT-LEgo4D21.919.418.5
RGB (N)ViT-LEgo4D24.221.420.9
RGB (V + N)ViT-LEgo4D24.621.421.2
", + "bbox": [ + 81, + 349, + 460, + 457 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "persion, as illustrated in Table 1c. We investigate two methods, namely future feature supervision and future label supervision. The results suggest that, compared to feature supervision, label supervision yields superior accuracy by incorporating stronger semantics derived from manual annotation. Furthermore, we explore the significance of deep supervision, i.e., multi-stage supervision. We observe that introducing multiple supervisions of real action labels improves performance.", + "bbox": [ + 75, + 535, + 468, + 671 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Shared Classifier. In Table 1d, we exploit the classifier design in deep supervision for short-term memory and anticipation. We observe that sharing classifier parameters separately for them yields better performance. When we use a full-shared classifier for memory and anticipation, sharing all feature samples between them leads to the best performance. These results indicate that all yielded features in the interaction processes enrich the feature samples to be classified, reaching a function similar to the data augmentation.", + "bbox": [ + 75, + 672, + 470, + 809 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Conditional Circular Interaction. Table 2 compares conditional circular interaction incorporating different interaction information streams, methods, and times. From (a) to (e), our experimental results demonstrate that the model's classification performance improves with the in", + "bbox": [ + 76, + 824, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/247fe4e160204479b8c27fd26e5de583ebef9aa32b8fee3e77add1ffff432aad.jpg", + "table_caption": [ + "Table 4: Exploring different visual encoders for EK100 action anticipation. V or N denotes the encoder is pretrained on verb or noun subset [5]. \"FT\" is that the encoder is fine-tuned on the classification task of EK100." + ], + "table_footnote": [], + "table_body": "
MethodTHUMOS'14TVSeries
KineticsANetKineticsANet
RED [15]-37.575.1-
TRN [57]-38.975.7-
OadTR [54]53.545.977.879.1
LSTR [58]52.650.180.8-
GateHUB [7]-54.282.0-
TesTra [67]56.855.3--
MAT (ours)58.257.382.681.5
", + "bbox": [ + 516, + 351, + 877, + 491 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 5: Action anticipation result on THUMOS'14 and TVSeries, mAP is reported for THUMOS'14 and mcAP for TVSeries.", + "bbox": [ + 498, + 501, + 892, + 542 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "creasing richness of interaction information. Moreover, we observe that latent information in the future is equally or even more critical to classify the current action than information from the distant past, as evidenced by the performance comparison between (c) and (e). We also investigate the effect of different interaction mechanisms, comparing (f) and (g), and the results indicate that the cross-attention (CA) mechanism outperforms average pooling and concatenation similar to [54], achieving a $2.1\\%$ higher accuracy. Lastly, we evaluate the impact of different interaction times $N_{t}$ , as illustrated by (g), (h), and (i). The experimental results reveal that the model's performance improves gradually with the increase of $N_{t}$ . Notably, the model attains its highest performance when interacting with all information $N_{t} = 2$ times.", + "bbox": [ + 496, + 565, + 890, + 792 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "MixClip+ for Anticipation. Table 1e presents the augmentation efficacy of MixClip+ or MixClip on long- and short-term memory. Notably, the baseline experiences a significant drop in action recall to $18.1\\%$ without data augmentation. However, the result is still significantly better than Testra [67] with MixClip ( $18.1\\%$ vs $17.6\\%$ ), as shown in Table 3. Furthermore, the results in row 3 reveal that MixClip", + "bbox": [ + 496, + 794, + 893, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "13830", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/4f0f9bfd0659ea569af65074301161f710a260044f7cb4697ae22b4aa45723b5.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodAugmentationOverallUnseenTail
LongShortVerbNounActionVerbNounActionVerbNounAction
LSTR‡[58]--39.644.122.634.335.318.739.041.620.7
TesTra‡[67]--40.044.823.234.636.019.039.442.120.9
MAT (ours)--41.846.124.936.537.920.140.843.222.8
TesTra‡[67]MixClip-39.745.625.136.337.219.239.042.422.2
MAT (ours)MixClip-42.647.325.938.337.619.741.844.023.1
MAT (ours)MixClipMixClip+44.548.326.339.938.120.343.446.623.7
", + "bbox": [ + 78, + 88, + 898, + 210 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/de8cdbdf5346165ce70f141b06059d5a8aa721f5173187cd153873b4f0f25598.jpg", + "table_caption": [ + "Table 6: Online action detection result on EPIC-Kitchens-100. Accuracy is measured by class-mean recall@5%. ‡ was reproduced by us because LSTR [58] and TesTra [67] did not report the result." + ], + "table_footnote": [], + "table_body": "
MethodArchTHUMOS'14TVSeriesHDD
KineticsANetKineticsANetSensor
CDC [45]CNN-44.4---
RED [15]RNN-45.3-79.227.4
TRN [57]RNN62.147.286.283.729.2
IDN [12]RNN60.350.086.184.7-
LAP [34]RNN-53.3-85.3-
PKD [66]CNN64.5-86.4--
WOAD [16]RNN67.1----
OadTR [54]Trans65.258.387.285.429.8
Colar [61]Trans66.959.488.186.030.6
LSTR [58]Trans69.565.389.188.1-
GateHUB [7]Trans70.769.189.688.432.1
TeSTra [67]Trans71.268.2---
MAT (Ours)Trans71.670.489.788.632.7
", + "bbox": [ + 80, + 262, + 464, + 483 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 7: Online action detection performances on THUMOS'14 [30], TVSeries [10], and HDD [42]. The mAP performance is reported for THUMOS'14 and HDD, while the mcAP is reported for TVSeries.", + "bbox": [ + 75, + 494, + 468, + 551 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "is not suited for short-term memory, as it cannot improve performance and may even degrade the results regarding the verb (32.1% vs 31.0%). However, the model achieves the best performance (19.5%) when performing MixClip and MixClip+ augmentation separately on long- and short-term memory. Moreover, we validate the augmentation of double-MixClip+ (in row 5) on long- and short-term memory and observe that the overall gain of the model is small, similar to double-MixClip (in row 3).", + "bbox": [ + 75, + 566, + 468, + 703 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4. Comparison with State-of-the-Art Methods", + "text_level": 1, + "bbox": [ + 76, + 710, + 444, + 727 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Action Anticipation. We compare MAT with prior methods on EPIC-Kitchens-100 for action anticipation, as shown in Table 3. We divide the experimental results into two parts, one part of the input modality is RGB, and the other is multi-modal input, such as optical flow and object features. Using the ImageNet-1K pretrained features, MAT significantly outperforms RULSTM [14], AVT [17], and TeSTra [67] on terms of verb, noun, and action (at least $2.5\\%$ , $3.0\\%$ , and $1.8\\%$ , respectively). MAT with RGB and optical flow features achieves $1.8\\%$ higher action recall than TeSTra with the same input, which can better reflect the ef", + "bbox": [ + 75, + 734, + 470, + 901 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "fectiveness of the modules we designed.", + "bbox": [ + 498, + 265, + 767, + 280 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In Table 4, we conduct an extensive analysis of the impact of various visual encoders on the performance of action anticipation. In particular, we leverage the ViT architecture [11], which is pre-trained on the largest egocentric dataset Ego4D [19], made available by [5], owing to its superior performance in Ego4D Challenges. Additionally, to compare the impact of first-person and third-person pretraining, we utilize the weights pretrained on the K400 [31], provided by VideoMAE [47]. The results suggest that encoders pre-trained on first-person datasets perform better than on widely-used third-person datasets. Moreover, leveraging the noun subset brings a huge performance boost, comparing pretraining on the verb subset of the Ego4D dataset. We suppose the noun subset with more object categories (the verb and noun subset include 118 and 582 categories) encourages the encoder to search more complex visual semantics. It highlights the critical role of egocentric perspective upstream pretraining method [38, 68] and diverse semantic annotations [19, 9, 29], which could have far-reaching implications for egocentric research.", + "bbox": [ + 496, + 280, + 890, + 582 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Following previous works [58, 7, 67], we further evaluate MAT on action anticipation tasks for THUMOS'14 and TVSeries. Unlike the previous work that required additional learnable tokens, we take the corresponding tokens from $\\mathbf{F}_A$ for forecasting. Table 5 shows that using the ActivityNet pretrained features, MAT significantly outperforms the existing methods by $2.0\\%$ and $0.6\\%$ on THUMOS'14 and TVSeries, respectively. Moreover, the performance of MAT can also be further improved when pretraining on Kinetics.", + "bbox": [ + 496, + 582, + 892, + 733 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Online Action Detection. We also compare MAT with other state-of-the-art online action detection methods [57, 58, 54, 61, 7] on THUMOS'14, TVSeries, and HDD. As illustrated in Table 7, our MAT achieves state-of-the-art performance and improves mAP by $2.2\\%$ on the THUMOS'14 dataset under the TSN-Anet feature input, and $0.4\\%$ under the TSN-Kinetics feature. For TVSeries, MAT is slightly better than GateHUB by $0.1\\%$ Furthermore, MAT achieves $0.6\\%$ better than the state-of-the-art GateHUB $(32.1\\%)$ method on HDD.", + "bbox": [ + 496, + 734, + 890, + 883 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "To further verify the effect of MAT, in Table 6, we offer", + "bbox": [ + 519, + 885, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "13831", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/37eefcc05c094367545c758271205dd7da024abf161ff7c275c5723b2a3cbeda.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Method#ParamFPSmAP
Optical FlowRGB FeatFlow FeatModelTotal
TRN402.9 M8.170.514.6123.38.147.2
OadTR75.8 M8.170.514.6110.08.158.3
LSTR58.0 M8.170.514.691.68.165.3
GateHUB45.2 M8.170.514.671.28.169.1
MAT (Ours)94.6 M8.170.514.672.68.170.4
", + "bbox": [ + 78, + 89, + 470, + 208 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 8: Efficiency comparison between MAT and the previous work on parameter (M) and inference speed (FPS)", + "bbox": [ + 76, + 220, + 468, + 250 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/5e6aabeedaa545e85a5a2cd69515be16a1599679ee3ea7ca1d29ae19eb8414ba.jpg", + "image_caption": [ + "Figure 6: Visualization of MAT's online prediction. The curves indicate the predicted confidence of the ground-truth class (High-Jump) with LSTR and our method." + ], + "image_footnote": [], + "bbox": [ + 78, + 263, + 470, + 339 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "the results for online action detection on the EK100 dataset. We divide the experimental results into two parts: one does not use augmentation, and the other uses MixClip or MixClip+. The results show that MAT surpasses the previous method by a large margin whether or not to use data augmentation. It is worth noting that when performing online action detection, we only need to take out the corresponding token in the short-term memory $\\widehat{\\mathbf{M}}_S$ for prediction. The superior performance of the model further highlights that MAT can simultaneously handle online action detection and anticipation tasks, thus integrating the two problems into a unified framework and performing excellently.", + "bbox": [ + 75, + 409, + 468, + 592 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5.5. Efficiency Analysis", + "text_level": 1, + "bbox": [ + 76, + 601, + 259, + 618 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 8 compares MAT with other methods in terms of model parameters and running time, conducted on a single Tesla V100. It is worth noting that under the same features, the efficiency bottleneck of the system remains in optical flow calculation and feature extraction. Our approach achieves a stronger performance while effectively balancing the trade-off between parameters and computational.", + "bbox": [ + 75, + 625, + 468, + 731 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5.6. Qualitative Analysis.", + "text_level": 1, + "bbox": [ + 76, + 741, + 272, + 758 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In Fig 6, we qualitatively analyzes the proposed MAT model. The confidence in the range [0, 1] on the y-axis denotes the probability of predicting the current action, e.g., HighJump. The figure highlights our MAT's successful suppression of background and high-confidence feedback of action segments compared with LSTR. The circular interaction of memory and anticipation provides reliable semantic information for the online prediction of the model, making the model offers a more sensitive and accurate torsion signal", + "bbox": [ + 75, + 763, + 470, + 902 + ], + "page_idx": 8 + }, + { + "type": "image", + "img_path": "images/ec9224486ed73be0889e595d38aa06b1ac67a43bb56a49cf53b8009e9a8c9410.jpg", + "image_caption": [ + "Figure 7: Attention weight visualization of different attention heads." + ], + "image_footnote": [], + "bbox": [ + 504, + 89, + 893, + 257 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "on the transition between background and foreground.", + "bbox": [ + 500, + 314, + 857, + 329 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5.7. Attention Visualization", + "text_level": 1, + "bbox": [ + 500, + 340, + 714, + 356 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Fig 7 depicts the attention weights of the last token of the short-term memory. It can be seen that under the blessing of future perception, MAT's multi-head attention mechanism pays attention to memory and anticipation simultaneously, leading to the model not limiting in history and attaining better performance.", + "bbox": [ + 496, + 364, + 893, + 455 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Conclusion and Future Work", + "text_level": 1, + "bbox": [ + 500, + 465, + 769, + 479 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We present Memory-and-Anticipation Transformer (MAT), a novel memory-anticipation-based paradigm for online action detection and anticipation, to overcome the weakness of most existing methods that can only complete modeling temporal dependency within a limited historical context. Through extensive experiments on four challenging benchmarks across two tasks, we show its applicability in predicting present or future actions, obtaining state-of-the-art results, and demonstrating the importance of circular interaction between memory and anticipation in the entire temporal structure. Although the temporal dimension is only considered in this work, we believe MAT would be a general paradigm for any AI system used to analyze video online and predict future events. In the near future, we will validate our model on more benchmarks and extend it to the long-term anticipation task. In the longer term, we will continue to unearth the intrinsic association of memory with anticipation and develop more effective forecasting models.", + "bbox": [ + 496, + 489, + 892, + 777 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgements", + "text_level": 1, + "bbox": [ + 500, + 787, + 666, + 804 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work was supported in part by National Key R&D Program of China (No. 2022ZD0160900), National Natural Science Foundation of China (Grant No. 61672273, 61832008, 62076119), and was also supported by the Fundamental Research Funds for the Central Universities XJ2023000701 and XJ2023004101.", + "bbox": [ + 496, + 809, + 893, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "13832", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In ICCV, pages 6816-6826, 2021. 2", + "[2] Iz Beltagy, Matthew E. Peters, and Arman Cohan. Longformer: The long-document transformer. CoRR, abs/2004.05150, 2020. 2", + "[3] Gedas Bertasius, Heng Wang, and Lorenzo Torresani. Is space-time attention all you need for video understanding? In ICML, volume 139, pages 813-824, 2021. 2", + "[4] Shuqiang Cao, Weixin Luo, Bairui Wang, Wei Zhang, and Lin Ma. A circular window-based cascade transformer for online action detection. CoRR, abs/2208.14209, 2022. 2", + "[5] Guo Chen, Sen Xing, Zhe Chen, Yi Wang, Kunchang Li, Yizhuo Li, Yi Liu, Jiahao Wang, Yin-Dong Zheng, Bingkun Huang, Zhiyu Zhao, Junting Pan, Yifei Huang, Zun Wang, Jiashuo Yu, Yinan He, Hongjie Zhang, Tong Lu, Yali Wang, Limin Wang, and Yu Qiao. Internvideo-ego4d: A pack of champion solutions to ego4d challenges. CoRR, abs/2211.09529, 2022. 7, 8", + "[6] Guo Chen, Yin-Dong Zheng, Jiahao Wang, Jilan Xu, Yifei Huang, Junting Pan, Yi Wang, Yali Wang, Yu Qiao, Tong Lu, and Limin Wang. Videollm: Modeling video sequence with large language models. CoRR, abs/2305.13292, 2023. 2", + "[7] Junwen Chen, Gaurav Mittal, Ye Yu, Yu Kong, and Mei Chen. Gatehub: Gated history unit with background suppression for online action detection. In CVPR, pages 19925-19934, 2022. 1, 2, 7, 8", + "[8] MMAction2 Contributors. Openmmlab's next generation video understanding toolbox and benchmark. https://github.com/open-mmlab/mmaction2, 2020.5", + "[9] Dima Damen, Hazel Doughty, Giovanni Maria Farinella, Antonino Furnari, Jian Ma, Evangelos Kazakos, Davide Moltisanti, Jonathan Munro, Toby Perrett, Will Price, and Michael Wray. Rescaling egocentric vision: Collection, pipeline and challenges for epic-kitchens-100. International Journal of Computer Vision (IJCV), 130:33-55, 2022. 2, 3, 5, 7, 8", + "[10] Roeland De Geest, Efstratios Gavves, Amir Ghodrati, Zhenyang Li, Cees Snoek, and Tinne Tuytelaars. Online action detection. In ECCV, pages 269-284, 2016. 1, 2, 5, 8", + "[11] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In 9th International Conference on Learning Representations, ICLR 2021, Virtual Event, Austria, May 3-7, 2021. OpenReview.net, 2021. 2, 8", + "[12] Hyunjun Eun, Jinyoung Moon, Jongyoul Park, Chanho Jung, and Changick Kim. Learning to discriminate information for online action detection. In CVPR, pages 806-815, 2020. 2, 8", + "[13] Haoqi Fan, Bo Xiong, Karttikeya Mangalam, Yanghao Li, Zhicheng Yan, Jitendra Malik, and Christoph Feichtenhofer." + ], + "bbox": [ + 78, + 114, + 467, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Multiscale vision transformers. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 6804-6815. IEEE, 2021. 2", + "[14] Antonino Furnari and Giovanni Maria Farinella. What would you expect? anticipating egocentric actions with rolling-unrolling lstms and modality attention. In International Conference on Computer Vision (ICCV), 2019. 1, 2, 5, 7, 8", + "[15] Jiyang Gao, Zhenheng Yang, and Ram Nevatia. RED: reinforced encoder-decoder networks for action anticipation. In BMVC, 2017. 2, 7, 8", + "[16] Mingfei Gao, Yingbo Zhou, Ran Xu, Richard Socher, and Caiming Xiong. WOAD: weakly supervised online action detection in untrimmed videos. In CVPR, pages 1915-1923, 2021. 2, 8", + "[17] Rohit Girdhar and Kristen Grauman. Anticipative Video Transformer. In ICCV, 2021. 1, 2, 5, 7, 8", + "[18] Rohit Girdhar, Mannat Singh, Nikhila Ravi, Laurens van der Maaten, Armand Joulin, and Ishan Misra. Omnivore: A single model for many visual modalities. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New Orleans, LA, USA, June 18-24, 2022, pages 16081-16091. IEEE, 2022. 2", + "[19] Kristen Grauman, Andrew Westbury, Eugene Byrne, Zachary Chavis, Antonino Furnari, Rohit Girdhar, Jackson Hamburger, Hao Jiang, Miao Liu, Xingyu Liu, Miguel Martin, Tushar Nagarajan, Ilija Radosavovic, Santhosh Kumar Ramakrishnan, Fiona Ryan, Jayant Sharma, Michael Wray, Mengmeng Xu, Eric Zhongcong Xu, Chen Zhao, Siddhant Bansal, Dhruv Batra, Vincent Cartillier, Sean Crane, Tien Do, Morrie Doulaty, Akshay Erapalli, Christoph Feichtenhofer, Adriano Fragomeni, Qichen Fu, Abrham Gebreselasie, Cristina Gonzalez, James Hillis, Xuhua Huang, Yifei Huang, Wenqi Jia, Wesley Khoo, Jachym Kolár, Satwik Kottur, Anurag Kumar, Federico Landini, Chao Li, Yanghao Li, Zhenqiang Li, Karttikeya Mangalam, Raghava Modhugu, Jonathan Munro, Tullie Murrell, Takumi Nishiyasu, Will Price, Paola Ruiz Puentes, Merey Ramazanova, Leda Sari, Kiran Somasundaram, Audrey Southerland, Yusuke Sugano, Ruijie Tao, Minh Vo, Yuchen Wang, Xindi Wu, Takuma Yagi, Ziwei Zhao, Yunyi Zhu, Pablo Arbeláez, David Crandall, Dima Damen, Giovanni Maria Farinella, Christian Fuegen, Bernard Ghanem, Vamsi Krishna Ithapu, C. V. Jawahar, Hanbyul Joo, Kris Kitani, Haizhou Li, Richard A. Newcombe, Aude Oliva, Hyun Soo Park, James M. Rehg, Yoichi Sato, Jianbo Shi, Mike Zheng Shou, Antonio Torralba, Lorenzo Torresani, Mingfei Yan, and Jitendra Malik. Ego4d: Around the world in 3,000 hours of egocentric video. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New Orleans, LA, USA June 18-24, 2022 pages 18973-18990. IEEE, 2022. 8", + "[20] Demis Hassabis, Dharshan Kumaran, Christopher Summerfield, and Matthew Botvinick. Neuroscience-inspired artificial intelligence. Neuron, 95(2):245-258, 2017. 2", + "[21] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dólar, and Ross B. Girshick. Masked autoencoders are scalable vision learners. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New" + ], + "bbox": [ + 503, + 92, + 890, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "13833", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Orleans, LA, USA, June 18-24, 2022, pages 15979-15988. IEEE, 2022. 6", + "[22] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778, 2016. 3", + "[23] Fabian Caba Heilbron, Victor Escorcia, Bernard Ghanem, and Juan Carlos Niebles. Activitynet: A large-scale video benchmark for human activity understanding. In CVPR, pages 961-970, 2015. 5", + "[24] Geoffrey E. Hinton, Nitish Srivastava, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. Improving neural networks by preventing co-adaptation of feature detectors. CoRR, abs/1207.0580, 2012. 5", + "[25] Yifei Huang, Minjie Cai, Zhenqiang Li, Feng Lu, and Yoichi Sato. Mutual context network for jointly estimating egocentric gaze and action. IEEE Transactions on Image Processing, 29:7795-7806, 2020. 2", + "[26] Yifei Huang, Minjie Cai, Zhenqiang Li, and Yoichi Sato. Predicting gaze in egocentric video by learning task-dependent attention transition. In Proceedings of the European conference on computer vision (ECCV), pages 754-769, 2018. 1", + "[27] Yifei Huang, Yusuke Sugano, and Yoichi Sato. Improving action segmentation via graph-based temporal reasoning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 14024-14034, 2020. 1", + "[28] Yifei Huang, Lijin Yang, and Yoichi Sato. Compound prototype matching for few-shot action recognition. In European Conference on Computer Vision, pages 351-368, 2022. 2", + "[29] Baoxiong Jia, Ting Lei, Song-Chun Zhu, and Siyuan Huang. Egotaskqa: Understanding human tasks in egocentric videos. CoRR, abs/2210.03929, 2022. 8", + "[30] Y.-G. Jiang, J. Liu, A. Roshan Zamir, G. Toderici, I. Laptev, M. Shah, and R. Sukthankar. THUMOS challenge: Action recognition with a large number of classes. http://crcv.ucf.edu/THUMOS14/, 2014. 2, 5, 8", + "[31] Will Kay, João Carreira, Karen Simonyan, Brian Zhang, Chloe Hillier, Sudheendra Vijayanarasimhan, Fabio Viola, Tim Green, Trevor Back, Paul Natsev, Mustafa Suleyman, and Andrew Zisserman. The kinetics human action video dataset. CoRR, abs/1705.06950, 2017. 5, 8", + "[32] Kris M Kitani, Brian D Ziebart, James Andrew Bagnell, and Martial Hebert. Activity forecasting. In Computer Vision-ECCV 2012: 12th European Conference on Computer Vision, Florence, Italy, October 7-13, 2012, Proceedings, Part IV 12, pages 201-214. Springer, 2012. 1", + "[33] Hema S Koppula and Ashutosh Saxena. Anticipating human activities using object affordances for reactive robotic response. IEEE transactions on pattern analysis and machine intelligence, 38(1):14-29, 2015. 1", + "[34] Sumin Lee, Hyunjun Eun, Jinyoung Moon, Seokeon Choi, Yoonhyung Kim, Chanho Jung, and Changick Kim. Learning to discriminate information for online action detection: Analysis and application. TPAMI, pages 1-17, 2022. 5, 8", + "[35] Kunchang Li, Yali Wang, Yinan He, Yizhuo Li, Yi Wang, Limin Wang, and Yu Qiao. Uniformerv2: Spatiotemporal learning by arming image vits with video uniformer. arXiv preprint arXiv:2211.09552, 2022. 2" + ], + "bbox": [ + 78, + 90, + 468, + 900 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[36] Kunchang Li, Yali Wang, Yizhuo Li, Yi Wang, Yinan He, Limin Wang, and Yu Qiao. Unmasked teacher: Towards training-efficient video foundation models. arXiv preprint arXiv:2303.16058, 2023. 2", + "[37] Zhiqi Li, Zhiding Yu, Wenhai Wang, Anima Anandkumar, Tong Lu, and Jose M Alvarez. Fb-bev: Bev representation from forward-backward view transformations. arXiv preprint arXiv:2308.02236, 2023. 2", + "[38] Kevin Qinghong Lin, Alex Jinpeng Wang, Mattia Soldan, Michael Wray, Rui Yan, Eric Zhongcong Xu, Difei Gao, Rong-Cheng Tu, Wenzhe Zhao, Weijie Kong, Chengfei Cai, Hongfa Wang, Dima Damen, Bernard Ghanem, Wei Liu, and Mike Zheng Shou. Egocentric video-language pretraining. CoRR, abs/2206.01670, 2022. 8", + "[39] Xiaolong Liu, Qimeng Wang, Yao Hu, Xu Tang, Song Bai, and Xiang Bai. End-to-end temporal action detection with transformer. CoRR, abs/2106.10271, 2021. 2", + "[40] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 9992-10002. IEEE, 2021. 2", + "[41] Giovanni Pezzulo, Francesco Rigoli, and Karl Friston. Active inference, homeostatic regulation and adaptive behavioural control. Progress in neurobiology, 134:17-35, 2015. 2", + "[42] Vasili Ramanishka, Yi-Ting Chen, Teruhisa Mitsu, and Kate Saenko. Toward driving scene understanding: A dataset for learning driver behavior and causal reasoning. In CVPR, 2018. 2, 5, 8", + "[43] Daniel L Schacter and Donna Rose Addis. The ghosts of past and future. Nature, 445(7123):27-27, 2007. 2", + "[44] Fadime Sener, Dipika Singhania, and Angela Yao. Temporal aggregate representations for long-range video understanding. In Andrea Vedaldi, Horst Bischof, Thomas Brox, and Jan-Michael Frahm, editors, Computer Vision - ECCV 2020 - 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XVI, volume 12361 of Lecture Notes in Computer Science, pages 154-171. Springer, 2020. 1, 7", + "[45] Zheng Shou, Jonathan Chan, Alireza Zareian, Kazuyuki Miyazawa, and Shih-Fu Chang. CDC: convolutional-deconvolutional networks for precise temporal action localization in untrimmed videos. In 2017 IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2017, Honolulu, HI, USA, July 21-26, 2017, pages 1417-1426. IEEE Computer Society, 2017. 8", + "[46] Bilge Soran, Ali Farhadi, and Linda Shapiro. Generating notifications for missing actions: Don't forget to turn the lights off! In Proceedings of the IEEE International Conference on Computer Vision, pages 4669-4677, 2015. 1", + "[47] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. Videomae: Masked autoencoders are data-efficient learners for self-supervised video pre-training. CoRR, abs/2203.12602, 2022. 8", + "[48] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Hervé Jégou. Training" + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "13834", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "data-efficient image transformers & distillation through attention. In Marina Meila and Tong Zhang, editors, Proceedings of the 38th International Conference on Machine Learning, ICML 2021, 18-24 July 2021, Virtual Event, volume 139 of Proceedings of Machine Learning Research, pages 10347-10357. PMLR, 2021. 2", + "[49] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. 2", + "[50] Limin Wang, Yuanjun Xiong, Zhe Wang, Yu Qiao, Dahua Lin, Xiaou Tang, and Luc Van Gool. Temporal segment networks: Towards good practices for deep action recognition. In ECCV, pages 20-36, 2016. 5", + "[51] Pichao Wang, Xue Wang, Fan Wang, Ming Lin, Shuning Chang, Hao Li, and Rong Jin. KVT: k-nn attention for boosting vision transformers. In Shai Avidan, Gabriel J. Brostow, Moustapha Cisse, Giovanni Maria Farinella, and Tal Hassner, editors, Computer Vision - ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXIV, volume 13684 of Lecture Notes in Computer Science, pages 285-302. Springer, 2022. 6", + "[52] Sinong Wang, Belinda Z. Li, Madian Khabsa, Han Fang, and Hao Ma. Linformer: Self-attention with linear complexity. CoRR, abs/2006.04768, 2020. 2", + "[53] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 548-558. IEEE, 2021. 2", + "[54] Xiang Wang, Shiwei Zhang, Zhiwu Qing, Yuanjie Shao, Zhengrong Zuo, Changxin Gao, and Nong Sang. Long short-term transformer for online action detection. In ICCV, 2021. 2, 5, 7, 8", + "[55] Yi Wang, Kunchang Li, Yizhuo Li, Yinan He, Bingkun Huang, Zhiyu Zhao, Hongjie Zhang, Jilan Xu, Yi Liu, Zun Wang, et al. Internvideo: General video foundation models via generative and discriminative learning. arXiv preprint arXiv:2212.03191, 2022. 2", + "[56] Chao-Yuan Wu, Yanghao Li, Karttikeya Mangalam, Haoqi Fan, Bo Xiong, Jitendra Malik, and Christoph Feichtenhofer. Memvit: Memory-augmented multiscale vision transformer for efficient long-term video recognition. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New Orleans, LA, USA, June 18-24, 2022, pages 13577-13587. IEEE, 2022. 2", + "[57] Mingze Xu, Mingfei Gao, Yi-Ting Chen, Larry S Davis, and David J Crandall. Temporal recurrent networks for online action detection. In ICCV, pages 5532-5541, 2019. 2, 5, 7, 8", + "[58] Mingze Xu, Yuanjun Xiong, Hao Chen, Xinyu Li, Wei Xia, Zhuowen Tu, and Stefano Soatto. Long short-term transformer for online action detection. In NeurIPS, 2021. 1, 2, 3, 5, 6, 7, 8", + "[59] Xinyu Xu, Yong-Lu Li, and Cewu Lu. Learning to anticipate future with dynamic context removal. In Proceedings of" + ], + "bbox": [ + 78, + 90, + 470, + 901 + ], + "page_idx": 11 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12734-12744, 2022. 7", + "[60] Antoine Yang, Antoine Miech, Josef Sivic, Ivan Laptev, and Cordelia Schmid. Tubedetr: Spatio-temporal video grounding with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 16442-16453, June 2022. 2", + "[61] Le Yang, Junwei Han, and Dingwen Zhang. Colar: Effective and efficient online action detection by consulting exemplars. In CVPR, 2022. 2, 5, 8", + "[62] Cunjun Yu, Xiao Ma, Jiawei Ren, Haiyu Zhao, and Shuai Yi. Spatio-temporal graph transformer networks for pedestrian trajectory prediction. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XII 16, pages 507-523. Springer, 2020. 1", + "[63] Chen-Lin Zhang, Jianxin Wu, and Yin Li. Actionformer: Localizing moments of actions with transformers. CoRR, abs/2202.07925, 2022. 2", + "[64] Hongyi Zhang, Moustapha Cisse, Yann N. Dauphin, and David Lopez-Paz. mixup: Beyond empirical risk minimization. In 6th International Conference on Learning Representations, ICLR 2018, Vancouver, BC, Canada, April 30 - May 3, 2018, Conference Track Proceedings. OpenReview.net, 2018. 6", + "[65] Yanyi Zhang, Xinyu Li, Chunhui Liu, Bing Shuai, Yi Zhu, Biagio Brattoli, Hao Chen, Ivan Marsic, and Joseph Tighe. Vidtr: Video transformer without convolutions. In ICCV, pages 13557-13567, 2021. 2", + "[66] Peisen Zhao, Jiajie Wang, Lingxi Xie, Ya Zhang, Yanfeng Wang, and Qi Tian. Privileged knowledge distillation for online action detection. CoRR, abs/2011.09158, 2020. 8", + "[67] Yue Zhao and Philipp Krahenbuhl. Real-time online video detection with temporal smoothing transformers. In European Conference on Computer Vision (ECCV), 2022. 1, 2, 3, 5, 6, 7, 8", + "[68] Yue Zhao, Ishan Misra, Philipp Krahenbuhl, and Rohit Girdhar. Learning video representations from large language models. CoRR, abs/2212.04501, 2022. 8" + ], + "bbox": [ + 501, + 92, + 893, + 628 + ], + "page_idx": 11 + }, + { + "type": "page_number", + "text": "13835", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 11 + } +] \ No newline at end of file diff --git a/2023/Memory-and-Anticipation Transformer for Online Action Understanding/a1b3a75e-11e3-4ea7-94a7-a5bef15574c1_model.json b/2023/Memory-and-Anticipation Transformer for Online Action Understanding/a1b3a75e-11e3-4ea7-94a7-a5bef15574c1_model.json new file mode 100644 index 0000000000000000000000000000000000000000..30bd3e6ab2a6b0776e59a01087af2a85e92fac43 --- /dev/null +++ b/2023/Memory-and-Anticipation Transformer for Online Action Understanding/a1b3a75e-11e3-4ea7-94a7-a5bef15574c1_model.json @@ -0,0 +1,2545 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.044 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.115, + 0.131, + 0.856, + 0.154 + ], + "angle": 0, + "content": "Memory-and-Anticipation Transformer for Online Action Understanding" + }, + { + "type": "text", + "bbox": [ + 0.17, + 0.18, + 0.8, + 0.235 + ], + "angle": 0, + "content": "Jiahao Wang\\(^{1*}\\) Guo Chen\\(^{1,2*}\\) Yifei Huang\\(^{2}\\) Limin Wang\\(^{1,2}\\) Tong Lu\\(^{1\\boxtimes}\\) \n\\(^{1}\\) State Key Laboratory for Novel Software Technology, Nanjing University \n\\(^{2}\\) Shanghai AI Laboratory" + }, + { + "type": "title", + "bbox": [ + 0.259, + 0.269, + 0.337, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.301, + 0.474, + 0.633 + ], + "angle": 0, + "content": "Most existing forecasting systems are memory-based methods, which attempt to mimic human forecasting ability by employing various memory mechanisms and have progressed in temporal modeling for memory dependency. Nevertheless, an obvious weakness of this paradigm is that it can only model limited historical dependence and can not transcend the past. In this paper, we rethink the temporal dependence of event evolution and propose a novel memory-anticipation-based paradigm to model an entire temporal structure, including the past, present, and future. Based on this idea, we present Memory-and-Anticipation Transformer (MAT), a memory-anticipation-based approach, to address the online action detection and anticipation tasks. In addition, owing to the inherent superiority of MAT, it can process online action detection and anticipation tasks in a unified manner. The proposed MAT model is tested on four challenging benchmarks TVSeries, THUMOS'14, HDD, and EPIC-Kitchens-100, for online action detection and anticipation tasks, and it significantly outperforms all existing methods. Code is available at https://github.com/Echo0125/Memory-and-Anticipation-Transformer." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.665, + 0.21, + 0.681 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.692, + 0.47, + 0.798 + ], + "angle": 0, + "content": "Online anticipation [32] or detection [10] in computer vision attempt to perceive future or present states from a historical perspective. They are the crucial factors of AI systems that engage with complex real environments and interact with other agents, e.g. wearable devices [46], human-robot interaction systems [33], and autonomous vehicles [62]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.799, + 0.471, + 0.875 + ], + "angle": 0, + "content": "Human beings frequently imagine future events based on past experiences. Similarly, anticipating future events inherently requires modeling past actions or the progression of events to predict what will happen next. To bridge the gap with human forecasting ability, current systems" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.268, + 0.892, + 0.499 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.51, + 0.895, + 0.622 + ], + "angle": 0, + "content": "Figure 1: Examples for the forward influence of memory and backward constraint of anticipation. (a) An athlete prepares to start, starts to run, and then jumps to form the result of completing a high jump; (b) The goals of a camera wearer for cutting a tomato dictate the sequence of actions he will perform: hold the knife, get ready to cut, etc.; (c) Compared with the memory-based method, the memory-anticipation-based method is able to establish circular dependencies between memory and future." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.642, + 0.892, + 0.779 + ], + "angle": 0, + "content": "strive to mimic this cognitive ability by employing different memory mechanisms [58, 26, 7, 67, 44, 17]. Previous research [14, 44] demonstrated that modeling long temporal context is crucial for accurate anticipation. LSTR [58] further decomposes the memory encoder into long and short-term stages for online action detection and anticipation, allowing for the extraction of more representative memory features. Similarly, research efforts such as [67, 7, 27] have also illustrated improvements based on this principle." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.893, + 0.902 + ], + "angle": 0, + "content": "However, despite various memory-based approaches, memory is not the only driver of present or future action. The synchronization between shot transitions and the evolution of actor behavior appears to cohere with the beliefs and wills of the event weavers, be they actors or camerewearers. In (a) and (b) of Fig 1, we use the examples of high jumping and cooking to show the forward influence of memory and backward constraint of anticipation." + }, + { + "type": "page_footnote", + "bbox": [ + 0.101, + 0.887, + 0.461, + 0.901 + ], + "angle": 0, + "content": "* Equal contribution, ⌒ Corresponding author (lutong@nju.edu.cn)" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "13824" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.471, + 0.212 + ], + "angle": 0, + "content": "Upon closer examination of both examples, it has been observed that future-oriented thoughts may impact action and memory, which seems modulated by the encoding of new information [43, 25]. Additionally, anticipation may change as ongoing behavior progresses and memory is updated [41, 20]. This indicates that there exists a circular interdependence between anticipation and memory, constraining the evolution of behavior or events." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.215, + 0.47, + 0.442 + ], + "angle": 0, + "content": "Based on the preceding analysis, we reevaluate the temporal dependencies inherent in memory-based methods. In their preoccupation with the impact of memory on anticipation, these memory-based methods tend to overlook the inverse direction of impact, i.e., anticipation on memory. Consequently, historical representations are not adequately corrected, thereby risking impeding any attempts to transcend the past. Against this backdrop, we assert that a comprehensive temporal structure seamlessly integrates memory and anticipation is indispensable. In other words, a memory-anticipation-based method building circular dependencies between memory and anticipation, as shown in Fig 1(c), holds tremendous promise for enhancing cognitive inference capabilities and advanced understanding of AI systems about the present and future." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.444, + 0.47, + 0.685 + ], + "angle": 0, + "content": "To this end, we propose Memory-and-Anticipation Transformer (MAT), a novel memory-anticipation-based approach that fully models the complete temporal context, including history, present, and future. A Progressive Memory Encoder is designed to provide a more precise history summary by compressing long- and short-term memory in a segment-based fashion. Meanwhile, we propose our key idea of modeling circular dependencies between memory and future, implemented as Memory-Anticipation Circular Decoder. It first learns latent future features in a supervised manner, then updates iteratively the enhanced short-term memory and the latent future features by performing Conditional circular Interaction between them. Among them, multiple interaction processes capture the circular dependency and supervise the output to maintain stable features with real semantics." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.687, + 0.47, + 0.809 + ], + "angle": 0, + "content": "Remarkably, owing to the inherent superiority of our model design, we are able to adapt both tasks, i.e., online action detection and anticipation, in a unified manner, spanning the training and online inference stages. For any given dataset, the MAT model obviates the need for separate training or testing for each task. Rather, a single training process is enough, and during inference, the corresponding token for each task can be extracted effortlessly." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.471, + 0.903 + ], + "angle": 0, + "content": "In summary, our contributions are 1). We rethink the temporal dependence of event evolution and propose a memory-anticipation-based paradigm for the circular interaction of memory and anticipation, introducing the concept of memory and future circular dependence. 2). We propose a unified architecture Memory-Anticipation Transformer" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.184 + ], + "angle": 0, + "content": "(MAT) that simultaneously processes online action detection and anticipation, showing effective performance. 3). MAT significantly outperforms all existing methods on four challenging benchmarks for online action detection and anticipation tasks, i.e., TVSeries [10], THUMOS'14 [30], HDD [42] and EPIC-Kitchens-100 [9]." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.196, + 0.642, + 0.212 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.221, + 0.892, + 0.463 + ], + "angle": 0, + "content": "Online Action Detection and Anticipation. Online action detection [10] aims to predict the action as it happens without accessing the future. Previous methods [57, 12, 16, 61, 54, 58, 7, 67, 4] for online action detection include recurrent networks, reinforcement learning, and, more recently, transformers. [15] uses a reinforced network to encourage making great decisions as early as possible. [57] adopts RNN to generate future predictions to improve online action detection. [58] proposes a transformer to scale the history spanning a longer duration. The target of action anticipation [9, 14, 17, 56] is predicting what actions will occur after a certain time. RULSTM [14] explores action anticipation and proposes an LSTM-based network to solve this problem. AVT [17] proposed an end-to-end attention-based model for anticipative video modeling and learns feature representations by self-supervised methods." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.464, + 0.892, + 0.614 + ], + "angle": 0, + "content": "Online action detection and anticipation share two key characteristics: the inability to perceive future representations, with information derived solely from historical context, and the goal of predicting actions after a certain time. Previous research has typically studied the model for each task in isolation [61, 7] or trained and tested them separately [58, 67], ignoring the potential benefits of leveraging their shared characteristics. We propose a novel unified framework, named MAT, to address this limitation, which allows us to train or infer both tasks simultaneously." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.615, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Transformer for Video Understanding. Transformers have proven successful in natural language processing [49], and researchers have shown increasing interest in its application to vision tasks [11, 48, 40, 53, 18, 37]. Several methods have been proposed to use transformers for temporal modeling in video-related tasks [1, 2, 6, 28, 35, 36, 39, 52, 55, 65]. Timesformer [3] proposes divided attention to capture spatial and temporal information for action recognition separately. MViT [13] builds a feature hierarchy by progressively expanding channel capacity and reducing video spatial-temporal resolution. Actionformer [63] adopts the transformer architecture with local attention for temporal action localization. TubeDETR [60] tackles video grounding with an encoder-decoder transformer-based architecture to efficiently encode spatial and multi-modal interactions. Our MAT model is also built upon the transformer, utilizing its encoder and decoder architectures. We meticulously integrate the transformer blocks to implement our memory encoder and memory-anticipation circular decoder." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13825" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.147, + 0.089, + 0.342, + 0.103 + ], + "angle": 0, + "content": "Progressive Memory Encoder" + }, + { + "type": "image_caption", + "bbox": [ + 0.453, + 0.089, + 0.71, + 0.103 + ], + "angle": 0, + "content": "Memory-Anticipation Circular Decoder" + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.104, + 0.894, + 0.251 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.254, + 0.895, + 0.325 + ], + "angle": 0, + "content": "Figure 2: MAT architecture. We first divide the temporal sequence into long-term and short-term memories. In Progressive Memory Encoder, long-term memory queries \\(\\mathbf{Q}_L\\) progressively map the long-term to an abstract representation and be fed to the transformer decoder block to enhance the short-term memory. Then the Memory-Anticipation Circular Decoder utilizes learnable queries \\(\\mathbf{Q}_F\\) and \\(\\mathbf{Q}_F'\\) to perceive the future context and circularly updates the historical and future representation. Finally, a weight-shared classifier is adopted to output the classification scores of short-term and future for online action detection and anticipation." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.349, + 0.228, + 0.367 + ], + "angle": 0, + "content": "3. Problem Setup" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.375, + 0.473, + 0.542 + ], + "angle": 0, + "content": "Online action anticipation and detection share a similar goal of predicting actions in untrimmed video sequences. In the former, we aim to forecast actions after a time gap \\(\\tau\\), as defined in [9], while in the latter, we predict the action under \\(\\tau = 0\\). Both tasks require classifying actions without access to future information during inference. We represent the input video as \\(\\mathbf{V} = \\{v_t\\}_{t = -T + 1}^0\\), and our objective is to predict the action category \\(\\tilde{y}_{\\tau} \\in \\{0,1,2,\\dots,C\\}\\) occurs after a specified time gap \\(\\tau\\) in the future. Here, \\(C\\) represents the total number of action categories, and label 0 denotes the background category." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.555, + 0.436, + 0.573 + ], + "angle": 0, + "content": "4. Memory-and-Anticipation Transformer" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.581, + 0.47, + 0.792 + ], + "angle": 0, + "content": "We now describe Memory-and-Anticipation Transformer (MAT) model architecture, as illustrated in Fig 2. It processes the memory cached in runtime to predict current or future actions. We adopt the encoder-decoder architecture to implement the model. The Progressive Memory Encoder is proposed to improve the quality of compressing long-term memory and enhancing short-term memory, which has a fundamental impact on anticipation and detection. MAT also employs our presented key component Memory-Anticipation Circular Decoder that generates the latent anticipation feature and conducts interaction between memory and anticipation in an iterative loop. We now introduce each model component in detail, followed by the training, online inference, and implementation details." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.802, + 0.342, + 0.818 + ], + "angle": 0, + "content": "4.1. Progressive Memory Encoder" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.824, + 0.471, + 0.903 + ], + "angle": 0, + "content": "We use video feature \\(\\mathbf{F} = \\{f_t\\}_{t = -T + 1}^0\\in \\mathbb{R}^{T\\times D}\\) generated by a pretrained feature extractor as the input to our model, where \\(D\\) and \\(T\\) are the dimension and length of the feature sequence, respectively. To better handle the long memory, following [58], we divide the feature sequence into" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.351, + 0.892, + 0.472 + ], + "angle": 0, + "content": "two consecutive memories. The first is the short-term memory that stores only a handful of recently occurred frames. It stores the feature vectors as \\(\\mathbf{M}_S = \\{f_t\\}_{t = -m_S + 1}^0\\) , where \\(m_{S}\\) denotes the length. The other, named long-term memory, contains the feature that is far away from the current time, which is defined as \\(\\mathbf{M}_L = \\{f_t\\}_{t = -T + 1}^{-m_S}\\) . We set \\(m_{L}\\) to be the length of the long-term memory, which is much longer than the short-term memory." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.474, + 0.893, + 0.685 + ], + "angle": 0, + "content": "In practice, Progressive Memory Encoder progressively encodes long- and short-term memories. It first compresses the long-term memory to an abstract representation and injects them into the short-term memory. Differing with previous works [58, 67] that separately tackle the long- and short-term memories by one long-term encoder and one short-term decoder, we integrate these two works into a single encoder architecture. It is due to our encoded short-term memory being served for decoders and not as the final output. In our experiments, we observe that the design of the memory encoder is crucial for model performance. Therefore, different with [58, 67], we introduce a novel long-term memory compression method to improve the quality of memory encoding." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.688, + 0.895, + 0.902 + ], + "angle": 0, + "content": "Segment-based Long-term Memory Compression. LSTR [58] adopts a two-stage compression technique to project the long-term memory to a fixed-length latent embedding. It implements a function similar to the bottleneck layer [22]. Long-term memory, however, represents a long token sequence that often carries much noise. It is problematic to generate attention weights while crossattention queries too many tokens with mixed noise. We propose Segment-based Long-term Memory Compression to alleviate the issue, as shown in Fig 3. Concretely, we first divide \\(\\mathbf{M}_L\\) into \\(N_{s}\\) non-overlapping memory segments \\(\\mathbf{S} = \\{\\mathbf{s}_i\\}_{i = 1}^{N_s}\\) of length \\(\\frac{m_L}{N_s}\\). We then employ \\(N_{L}\\) learnable tokens \\(\\mathbf{Q}_L\\in \\mathbb{R}^{N_L\\times D}\\) as the long-term memory queries and a weight-shared transformer decoder block to query" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "13826" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.091, + 0.47, + 0.198 + ], + "angle": 0, + "content": "each segment. \\(\\mathbf{S}\\) will be transformed to \\(N_{s}\\) segment-level abstract feature \\(\\mathbf{F} = \\{\\mathbf{f}_i\\}_{i = 1}^{N_s}\\), where \\(\\mathbf{f}_i\\in \\mathbb{R}^{N_L\\times D}\\). We average pool each \\(\\mathbf{f}_i\\) to one vector \\(\\mathbb{R}^D\\) and concatenate them to form the long-term compressed segmented memory \\(\\mathbf{M}_L^s\\in \\mathbb{R}^{N_s\\times D}\\). At last, we feed them into two transformer encoder blocks to obtain the final compressed longterm memory \\(\\widehat{\\mathbf{M}}_L\\in \\mathbb{R}^{N_s\\times D}\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.199, + 0.471, + 0.399 + ], + "angle": 0, + "content": "Short-term Memory Enhancement. As short-term memory \\(\\mathbf{M}_S = \\{f_t\\}_{t = -m_S + 1}^0\\) contains crucial trends for accurately predicting the current or upcoming activities, we leverage short-term memory as the query to retrieve relevant context from the compressed long-term memory. As illustrated in Fig 2, we employ a transformer causal decoder block to aggregate compressed long-term memory \\(\\widehat{\\mathbf{M}}_L\\) into short-term memory. The enhanced short-term memory \\(\\widehat{\\mathbf{M}}_S\\) is then used to identify actions at each timestep, constituting a sequence of previously occurring actions and predicting future states and actions. We use frame-level action labels to supervise the dense classification task, encouraging the model to produce a clear sequence of historical behavior." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.405, + 0.42, + 0.421 + ], + "angle": 0, + "content": "4.2. Memory-Anticipation Circular Decoder" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.429, + 0.47, + 0.564 + ], + "angle": 0, + "content": "To implement our key idea that considers the co-reaction between anticipation and memory, we carefully design Memory-Anticipation Circular Decoder that circularly performs interaction between them. It first generates the latent anticipation that is a prerequisite for memory-anticipation interaction. Then, Conditional Circular Interaction will generate new memories and anticipation conditioned on old ones iteratively. Finally, a weight-shared classification head will supervise the generated memories and anticipation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.565, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Latent Anticipation Generation. Initially, we do not have an anticipation state. Therefore, we must first generate a latent anticipation feature, i.e., a future representation containing abstract information derived from known memory. Given the compressed long-term memory \\(\\widehat{\\mathbf{M}}_L\\) and short-term memory \\(\\widehat{\\mathbf{M}}_S\\), we first concatenate them to form the entire memory \\(\\mathbf{M}_E = [\\widehat{\\mathbf{M}}_L, \\widehat{\\mathbf{M}}_S]\\), where \\([\\cdot, \\cdot]\\) is the concatenating operation along the temporal dimension. Then, we use \\(N_F\\) future queries \\(\\mathbf{Q}_F \\in \\mathbb{R}^{N_F \\times D}\\) and a transformer decoder block to query \\(\\mathbf{M}_E\\). The updated future queries are represented as the latent anticipation features \\(\\mathbf{F}_A \\in \\mathbb{R}^{N_F \\times D}\\) at the current state. We use future information, e.g., future video features and future action labels, to supervise \\(\\mathbf{F}_A\\). In practice, we use information from the next \\(T_F\\) seconds. Since \\(\\mathbf{F}_A\\) is only used to describe the latent future states, too large future embeddings may overfit the anticipation representation. We set \\(N_F\\) to be smaller than the length of the used future information sequence. Then we use bilinear interpolation to upsample it to align for point-to-point supervision. Note that although we use future information here, this does not lead to an information leak. The model will generate preliminary anticipation" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.091, + 0.892, + 0.253 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.266, + 0.892, + 0.308 + ], + "angle": 0, + "content": "Figure 3: Segment-based Long-term Memory Compression. For example, given \\( m_{L} = 9 \\), \\( N_{s} = 3 \\), the process is shown above. We can finally obtain compressed features \\( \\widehat{M}_L \\) of length 3." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.336, + 0.888, + 0.35 + ], + "angle": 0, + "content": "in the inference phase and not use future labels or features." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.351, + 0.892, + 0.456 + ], + "angle": 0, + "content": "Conditional Circular Interaction. So far, we have generated long-term memory \\(\\widehat{\\mathbf{M}}_L\\), short-term memory \\(\\widehat{\\mathbf{M}}_S\\) and latent anticipation features \\(\\mathbf{F}_A\\). The memories, however, are limited to the past and can not go beyond history. We now describe how Conditional Circular Interaction works. For brevity, we detail how memory and anticipation interact with each other one time." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.456, + 0.892, + 0.507 + ], + "angle": 0, + "content": "As shown in Fig 4, we first concatenate \\(\\widehat{\\mathbf{M}}_L\\), \\(\\widehat{\\mathbf{M}}_S\\) and \\(\\mathbf{F}_A\\) to form the entire feature \\(\\mathbf{F}_E = [\\widehat{\\mathbf{M}}_L, \\widehat{\\mathbf{M}}_S, \\mathbf{F}_A]\\). Then, \\(\\mathbf{F}_E\\) and \\(\\widehat{\\mathbf{M}}_S\\) are feed into a transformer decoder block:" + }, + { + "type": "equation", + "bbox": [ + 0.583, + 0.518, + 0.891, + 0.537 + ], + "angle": 0, + "content": "\\[\n\\widehat {\\mathbf {M}} _ {S} ^ {\\prime} = \\operatorname {C r o s s A t t n} \\left(\\widehat {\\mathbf {M}} _ {S}, \\mathbf {F} _ {E}, \\mathbf {F} _ {E}\\right), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.548, + 0.892, + 0.693 + ], + "angle": 0, + "content": "where \\(\\mathrm{CrossAttn}(Q,K,V)\\) is the cross-attention layer in the transformer decoder block. The updated short-term memory is represented as \\(\\widehat{\\mathbf{M}}_S^{\\prime}\\). Since \\(\\mathbf{F}_E\\) contains memories and anticipation, \\(\\widehat{\\mathbf{M}}_S\\) as a query condition dynamically extracts new semantics mixed with memories and anticipation from three representations. Next, we re-concatenate \\(\\widehat{\\mathbf{M}}_L\\), \\(\\widehat{\\mathbf{M}}_S^{\\prime}\\) and \\(\\mathbf{F}_A\\) to generate the new entire feature \\(\\mathbf{F}_E^{\\prime} = [\\widehat{\\mathbf{M}}_L,\\widehat{\\mathbf{M}}_S^{\\prime},\\mathbf{F}_A]\\). Another transformer decoder block is used to query \\(\\mathbf{F}_E^{\\prime}\\), with \\(\\mathbf{F}_A\\) as the query condition:" + }, + { + "type": "equation", + "bbox": [ + 0.588, + 0.704, + 0.891, + 0.721 + ], + "angle": 0, + "content": "\\[\n\\mathbf {F} _ {A} ^ {\\prime} = \\operatorname {C r o s s A t t n} \\left(\\mathbf {F} _ {A}, \\mathbf {F} _ {E} ^ {\\prime}, \\mathbf {F} _ {E} ^ {\\prime}\\right), \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.733, + 0.891, + 0.793 + ], + "angle": 0, + "content": "where \\(\\mathbf{F}_A^\\prime\\) is the resulting anticipation features. After that, \\(\\mathbf{F}_A^\\prime\\) is injected with the higher-order inferred semantics brought about by the interaction between memory and anticipation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.794, + 0.892, + 0.902 + ], + "angle": 0, + "content": "In the interaction process, the generated \\(\\widehat{\\mathbf{M}}_S^{\\prime}\\) is both supervised like the above initial anticipation features. It should be noted that different from generating latent initial anticipation through fewer future queries, we find that using a new group of future queries \\(\\mathbf{Q}_F^{\\prime} \\in \\mathbb{R}^{N_F^{\\prime} \\times D}\\) strictly aligned future information sequences of \\(T_{F}\\) seconds in the first interaction process to replace the \\(\\mathbf{F}_A\\) with \\(\\mathbf{Q}_F^{\\prime}\\), bring" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13827" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.08, + 0.089, + 0.473, + 0.222 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.232, + 0.471, + 0.274 + ], + "angle": 0, + "content": "Figure 4: Conditional circular interaction dynamically updates and re-constructs the context between memories and anticipation by aggregating different temporal information." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.297, + 0.47, + 0.422 + ], + "angle": 0, + "content": "performance improvement. Thus, we point-to-point supervise the anticipation \\(\\mathbf{F}_A^\\prime\\) generated by each interaction process. Meanwhile, this design is more natural to output the corresponding token according to the anticipation gap time. We circularly perform the interaction process \\(N_{t}\\) times until saturation. The yielded \\(\\widehat{\\mathbf{M}}_S^{\\prime}\\) and \\(\\mathbf{F}_A^\\prime\\) in one interaction process become the new \\(\\widehat{\\mathbf{M}}_S\\) and \\(\\mathbf{F}_A\\) and are passed to the next interaction process." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.43, + 0.182, + 0.446 + ], + "angle": 0, + "content": "4.3. Training" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.453, + 0.47, + 0.558 + ], + "angle": 0, + "content": "Our MAT model relies on action steps of short-term memory to predict the current or future action. These steps are utilized as auxiliary information to benefit action detection and anticipation. It is worth noting that since the MAT model regards online action detection and anticipation as the same tasks with different settings, we can define the loss function in a unified fashion." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.559, + 0.471, + 0.667 + ], + "angle": 0, + "content": "For the \\(\\widehat{\\mathbf{M}}_S\\) generated by the encoder, we feed it to a classifier to generate the action probabilities \\(\\widehat{\\mathbf{Y}}_S = \\{\\widehat{\\mathbf{y}}_S^i\\}_{i=1}^{m_S}\\). We then supervise the whole short-term memory using a cross-entropy loss with the labeled action, \\(\\{c_S^i\\}_{i=1}^{m_S}\\). Learned future features \\(\\mathbf{F}_A\\) are fed into the same classifier to generate the probabilities \\(\\widehat{\\mathbf{Y}}_F = \\{\\widehat{\\mathbf{y}}_F^i\\}_{i=1}^{N_F}\\) and we also adopt a cross-entropy loss with the target, \\(\\{c_F^i\\}_{i=1}^{m_S}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.101, + 0.673, + 0.47, + 0.715 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {S} ^ {0} = - \\sum_ {i = 1} ^ {m _ {S}} \\log \\widehat {\\mathbf {y}} _ {S} ^ {i} [ c _ {S} ^ {i} ], \\mathcal {L} _ {F} ^ {0} = - \\sum_ {i = 1} ^ {N _ {F}} \\log \\widehat {\\mathbf {y}} _ {F} ^ {i} [ c _ {F} ^ {i} ], \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.722, + 0.47, + 0.829 + ], + "angle": 0, + "content": "where \\(\\mathcal{L}_S^0\\) and \\(\\mathcal{L}_F^0\\) are the loss function of encoded shortterm memory and initial anticipation features, respectively. As the conditional circular interaction is conducted \\(N_{t}\\) times, we use \\(\\mathcal{L}_S^i\\) and \\(\\mathcal{L}_F^i\\) to represent the loss of memory and anticipation in each interaction process, where \\(1\\leq i\\leq N_{t}\\). Their calculation is similar to \\(\\mathcal{L}_S^0\\) and \\(\\mathcal{L}_F^0\\). The final training loss is formulated by:" + }, + { + "type": "equation", + "bbox": [ + 0.169, + 0.836, + 0.47, + 0.879 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} = \\sum_ {i = 0} ^ {N _ {t}} \\lambda_ {s} ^ {i} \\cdot \\mathcal {L} _ {S} ^ {i} + \\lambda_ {f} \\sum_ {i = 0} ^ {N _ {t}} \\mathcal {L} _ {F} ^ {i}, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.886, + 0.379, + 0.902 + ], + "angle": 0, + "content": "where \\(\\lambda_s^i\\) and \\(\\lambda_{f}\\) are the balance coefficients." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.091, + 0.667, + 0.106 + ], + "angle": 0, + "content": "4.4. Online Inference" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.115, + 0.894, + 0.256 + ], + "angle": 0, + "content": "The existing works [57, 61, 58, 67, 17] test each task independently. Thanks to the design of the unified framework, MAT simultaneously infers online action detection and anticipation tasks on one streaming video. It uses the output \\(\\widehat{\\mathbf{M}}_S\\) and \\(\\mathbf{F}_A\\) produced by the last interaction as results of online action detection and anticipation, respectively. We take out the last token of \\(\\widehat{\\mathbf{M}}_S\\) for online action detection. For action anticipation, according to gap time \\(\\tau\\), we take out the corresponding token from \\(\\mathbf{F}_A\\) for forecasting." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.27, + 0.634, + 0.287 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.295, + 0.692, + 0.31 + ], + "angle": 0, + "content": "5.1. Dataset and Metrics" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.32, + 0.892, + 0.485 + ], + "angle": 0, + "content": "Dataset. We test on three online action detection datasets. THUMOS'14 [30] consists of over 20 hours of sports video annotated with 20 actions. TVSeries [10] includes 27 episodes of 6 popular TV series, about 150 minutes each and 16 hours total. HDD [42] is a largescale human driving video dataset comprising 104 hours of untrimmed videos and 11 action categories. Furthermore, we evaluate on EpicKitchens-100 [9] that contains 100 hours of egocentric videos with at least 90K action segments and whose narrations are mapped to 97 verb classes and 300 noun classes." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.487, + 0.892, + 0.593 + ], + "angle": 0, + "content": "Evaluation Metrics. For online action detection, following previous works [10, 34, 54, 58, 61], we use per-frame mean Average Precision (mAP) on THUMOS'14 and HDD, and per-frame mean calibrated Average Precision (mcAP) [10] on TVSeries. For action anticipation, we employ Top-5 Verb/Noun/Action Recall to measure the performance with an anticipation period \\(\\tau = 1s\\) [9]." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.605, + 0.715, + 0.621 + ], + "angle": 0, + "content": "5.2. Implementation details" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.629, + 0.892, + 0.779 + ], + "angle": 0, + "content": "Following prior works [57, 58, 67], we conduct our experiments on pre-extracted features. For TVSeries and THUMOS'14, we first resample the videos at 24 FPS and then extract the frames at 4 FPS for training and validation. We adopt a two-stream network [50] to extract feature. We use off-the-shell checkpoint released by mmentation2 [8] that pretrained on ActivityNet v1.3 [23] and Kinetics [31] to extract frame-level RGB and optical features. On EK100, following [14], we resample the videos at 30 FPS and then fine-tune the two-stream TSN on the classification task." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Memory Dropping. Despite the promising capabilities of the dense attention mechanism, capturing long-range dependencies remains a challenge. However, relying on the dense attention mechanism may lead to sub-optimization of the network, resulting in a locally optimal solution. We seek to explore memory-dropping strategies for implementing sparse attention during training. We experiment with various approaches, including dropout [24], top-k selec" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13828" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.088, + 0.088, + 0.191, + 0.179 + ], + "angle": 0, + "content": "
NsmAP
[58]69.6
269.8
470.2
870.4
1270.1
" + }, + { + "type": "table", + "bbox": [ + 0.203, + 0.089, + 0.323, + 0.151 + ], + "angle": 0, + "content": "
renewalmAP
070.0
170.4
269.7
" + }, + { + "type": "table", + "bbox": [ + 0.334, + 0.089, + 0.507, + 0.165 + ], + "angle": 0, + "content": "
deepsupervisionmAP
-cls69.9
✓feat69.6
✓cls70.4
✓feat + cls70.2
" + }, + { + "type": "table", + "bbox": [ + 0.52, + 0.089, + 0.685, + 0.154 + ], + "angle": 0, + "content": "
shortfuturemAP
unshared69.6
separately shared70.1
full shared70.4
" + }, + { + "type": "table", + "bbox": [ + 0.696, + 0.089, + 0.888, + 0.179 + ], + "angle": 0, + "content": "
longshortVNA
--32.136.118.1
MC-32.936.918.4
MCMC31.037.418.5
MCMC+35.038.819.5
MC+MC+31.636.818.4
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.082, + 0.186, + 0.19, + 0.21 + ], + "angle": 0, + "content": "(a) Segment number." + }, + { + "type": "table_footnote", + "bbox": [ + 0.197, + 0.187, + 0.322, + 0.211 + ], + "angle": 0, + "content": "(b) Future queries renewing." + }, + { + "type": "table_footnote", + "bbox": [ + 0.352, + 0.187, + 0.482, + 0.199 + ], + "angle": 0, + "content": "(c) Future supervision." + }, + { + "type": "table_footnote", + "bbox": [ + 0.541, + 0.187, + 0.657, + 0.198 + ], + "angle": 0, + "content": "(d) Shared classifier." + }, + { + "type": "table_footnote", + "bbox": [ + 0.75, + 0.187, + 0.828, + 0.199 + ], + "angle": 0, + "content": "(e) MixClip+." + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.223, + 0.894, + 0.252 + ], + "angle": 0, + "content": "Table 1: Ablation Experiments. We conduct detailed ablation on (a): Segment number, (b): Future queries renewing, (c): Future supervision, (d): Shared classifier, and (e): MixClip+. The gray rows denote default choices." + }, + { + "type": "table_caption", + "bbox": [ + 0.108, + 0.276, + 0.465, + 0.29 + ], + "angle": 0, + "content": "long short future interaction \\(N_{t}\\) detection anticipation" + }, + { + "type": "table", + "bbox": [ + 0.08, + 0.292, + 0.47, + 0.424 + ], + "angle": 0, + "content": "
(a)--67.6+0.053.7+0.0
(b)✓CA168.3+0.754.7+1.0
(c)✓✓CA168.9+1.355.3+1.6
(d)✓✓CA168.6+1.055.8+2.1
(e)✓✓CA169.2+1.656.1+2.4
(f)✓✓✓Avg&Cat168.3+0.755.3+1.6
(g)✓✓✓CA169.9+2.356.6+2.9
(h)✓✓✓CA270.4+2.957.3+3.6
(i)✓✓✓CA370.2+2.657.1+3.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.433, + 0.47, + 0.476 + ], + "angle": 0, + "content": "Table 2: Ablation study on the information stream, interaction method, and times for Conditional Circular Interaction. The shallow gray row denotes the baseline setting without any interaction." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.491, + 0.47, + 0.536 + ], + "angle": 0, + "content": "tion [51], and token dropping [21]. We compare these strategies, recorded in the supplementary material, and find that the top-k selection yields the best performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.537, + 0.47, + 0.657 + ], + "angle": 0, + "content": "MixClip+. TesTra [67] proposed an augmentation technique called MixClip to solve over-fitting caused by large long-term memory. Unlike long-term memory which presents an abstract concept, short-term memory provides a continuous motion trend, often playing a decisive role in anticipation. It leads to the fact that MixClip damages the continuity of motion, thereby, does not apply to short-term memory. We propose MixClip+ to solve the issue." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.658, + 0.47, + 0.763 + ], + "angle": 0, + "content": "In addition to mixing augmentation for long-term memory, we mix each feature token of short-term memory with a random clip from different videos. To maintain the continuity of short-term memory, we adopt soft fusion with hyperparameter \\(\\alpha = 0.25\\) to mix features and the corresponding labels, similar to Mixup [64]. Due to space limitations, we will describe this part in the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.772, + 0.231, + 0.789 + ], + "angle": 0, + "content": "5.3. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.469, + 0.856 + ], + "angle": 0, + "content": "Now we analyze the MAT model, using the two-stream features pretrained on ActivityNet v1.3 and THUMOS'14 test set as the test bed. Furthermore, we also study the contribution of the proposed MixClip+ on EPIC-Kitchens-100." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Segment Number. We evaluate the effect of segment number \\( N_{s} \\) for long-term memory compression in Table 1a. We find even a small \\( N_{s} \\) can improve performance, com" + }, + { + "type": "image", + "bbox": [ + 0.517, + 0.278, + 0.878, + 0.43 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.444, + 0.892, + 0.472 + ], + "angle": 0, + "content": "Figure 5: Generating latent anticipation with different anticipation length \\( T_{F} \\) and numbers of learnable tokens \\( N_{F} \\)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.49, + 0.892, + 0.55 + ], + "angle": 0, + "content": "pared with two-stage compression [58]. However, too many segments result in too little information within each segment to effectively capture temporal dependency. We use \\( N_{s} = 8 \\) as the default in the following ablation experiments." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.552, + 0.893, + 0.734 + ], + "angle": 0, + "content": "Query Number and Anticipation Length. Fig 5 compares generating latent anticipation using \\( N_{F} \\) learnable tokens with different anticipation lengths \\( T_{F} \\). The experimental results indicate that, for \\( T_{F} \\leq 4 \\), a larger \\( N_{F} \\) yields superior results owing to strongly correlated semantics of short-term memory and short-term anticipation thus, the model can benefit from more tokens. We observe that \\( N_{F} = 8,16,32 \\) exhibits a similar trend in the accuracy curve, with the model achieving optimal performance with \\( N_{F} = 32 \\). This suggests that long-term anticipation is more adaptable for sparse tokens. The observations imply that anticipation is also suitable for long- and short-term modeling." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.734, + 0.892, + 0.869 + ], + "angle": 0, + "content": "Future Queries Renewal. As Section 4.2 outlines, renewing future queries before the initial interaction improves performance. In Table 1b, we compare different renewing times (\"0\" denotes no renewal and utilizes \\( F_{A} \\)). A plausible explanation is that, in the first interaction process, the interaction from anticipation to memory adjusts the old memory, causing its domain to shift largely, which leads to insufficient interaction from the new memory to the initial anticipation feature." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Future Supervision. In addition, we carry out diverse experiments to determine the optimal choice of future su" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13829" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.08, + 0.089, + 0.902, + 0.3 + ], + "angle": 0, + "content": "
MethodModalityInitOverallUnseenTail
VerbNounActionVerbNounActionVerbNounAction
RULSTM [14]RGBIN-1K27.529.013.329.823.813.119.921.410.6
AVT [17]IN-1K27.230.713.6------
AVT [17]IN-21K30.231.714.9------
DCR [59]IN-1K31.031.114.6------
TeSTra [67]IN-1K26.836.217.027.130.113.319.328.613.7
MAT (Ours)IN-1K32.739.718.831.732.112.725.732.416.0
RULSTM [14]RGB + OF + OBJIN-1K27.830.814.028.827.214.219.822.011.1
TempAgg [44]IN-1K23.231.414.728.026.214.514.522.514.8
AVT+ [17]IN-1K25.531.814.825.523.611.518.525.812.6
AVT+ [17]IN-21K28.232.015.929.526.012.823.229.214.1
TeSTra [67]RGB + OFIN-1K30.835.817.629.626.012.823.229.214.2
MAT (Ours)IN-1K35.038.819.532.530.313.828.733.116.9
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.31, + 0.893, + 0.34 + ], + "angle": 0, + "content": "Table 3: Comparison to prior work on EPIC-Kitchens-100 Action Anticipation [9]. Accuracy measured by class-mean recall@5(%) following the standard protocol." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.351, + 0.462, + 0.458 + ], + "angle": 0, + "content": "
ModalityEncoderInitFTOverallUnseenTail
RGBTSNIN-1K✓18.812.716.0
RGB + OFTSNIN-1K✓19.513.816.9
RGBViT-LK40019.116.216.1
RGB (V)ViT-LEgo4D21.919.418.5
RGB (N)ViT-LEgo4D24.221.420.9
RGB (V + N)ViT-LEgo4D24.621.421.2
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.468, + 0.47, + 0.524 + ], + "angle": 0, + "content": "Table 4: Exploring different visual encoders for EK100 action anticipation. V or N denotes the encoder is pretrained on verb or noun subset [5]. \"FT\" is that the encoder is fine-tuned on the classification task of EK100." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.536, + 0.47, + 0.672 + ], + "angle": 0, + "content": "persion, as illustrated in Table 1c. We investigate two methods, namely future feature supervision and future label supervision. The results suggest that, compared to feature supervision, label supervision yields superior accuracy by incorporating stronger semantics derived from manual annotation. Furthermore, we explore the significance of deep supervision, i.e., multi-stage supervision. We observe that introducing multiple supervisions of real action labels improves performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.673, + 0.471, + 0.81 + ], + "angle": 0, + "content": "Shared Classifier. In Table 1d, we exploit the classifier design in deep supervision for short-term memory and anticipation. We observe that sharing classifier parameters separately for them yields better performance. When we use a full-shared classifier for memory and anticipation, sharing all feature samples between them leads to the best performance. These results indicate that all yielded features in the interaction processes enrich the feature samples to be classified, reaching a function similar to the data augmentation." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.825, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Conditional Circular Interaction. Table 2 compares conditional circular interaction incorporating different interaction information streams, methods, and times. From (a) to (e), our experimental results demonstrate that the model's classification performance improves with the in" + }, + { + "type": "table", + "bbox": [ + 0.517, + 0.352, + 0.878, + 0.492 + ], + "angle": 0, + "content": "
MethodTHUMOS'14TVSeries
KineticsANetKineticsANet
RED [15]-37.575.1-
TRN [57]-38.975.7-
OadTR [54]53.545.977.879.1
LSTR [58]52.650.180.8-
GateHUB [7]-54.282.0-
TesTra [67]56.855.3--
MAT (ours)58.257.382.681.5
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.502, + 0.893, + 0.543 + ], + "angle": 0, + "content": "Table 5: Action anticipation result on THUMOS'14 and TVSeries, mAP is reported for THUMOS'14 and mcAP for TVSeries." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.566, + 0.892, + 0.793 + ], + "angle": 0, + "content": "creasing richness of interaction information. Moreover, we observe that latent information in the future is equally or even more critical to classify the current action than information from the distant past, as evidenced by the performance comparison between (c) and (e). We also investigate the effect of different interaction mechanisms, comparing (f) and (g), and the results indicate that the cross-attention (CA) mechanism outperforms average pooling and concatenation similar to [54], achieving a \\(2.1\\%\\) higher accuracy. Lastly, we evaluate the impact of different interaction times \\(N_{t}\\), as illustrated by (g), (h), and (i). The experimental results reveal that the model's performance improves gradually with the increase of \\(N_{t}\\). Notably, the model attains its highest performance when interacting with all information \\(N_{t} = 2\\) times." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.895, + 0.903 + ], + "angle": 0, + "content": "MixClip+ for Anticipation. Table 1e presents the augmentation efficacy of MixClip+ or MixClip on long- and short-term memory. Notably, the baseline experiences a significant drop in action recall to \\(18.1\\%\\) without data augmentation. However, the result is still significantly better than Testra [67] with MixClip (\\(18.1\\%\\) vs \\(17.6\\%\\)), as shown in Table 3. Furthermore, the results in row 3 reveal that MixClip" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "13830" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.079, + 0.089, + 0.9, + 0.212 + ], + "angle": 0, + "content": "
MethodAugmentationOverallUnseenTail
LongShortVerbNounActionVerbNounActionVerbNounAction
LSTR‡[58]--39.644.122.634.335.318.739.041.620.7
TesTra‡[67]--40.044.823.234.636.019.039.442.120.9
MAT (ours)--41.846.124.936.537.920.140.843.222.8
TesTra‡[67]MixClip-39.745.625.136.337.219.239.042.422.2
MAT (ours)MixClip-42.647.325.938.337.619.741.844.023.1
MAT (ours)MixClipMixClip+44.548.326.339.938.120.343.446.623.7
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.221, + 0.893, + 0.25 + ], + "angle": 0, + "content": "Table 6: Online action detection result on EPIC-Kitchens-100. Accuracy is measured by class-mean recall@5%. ‡ was reproduced by us because LSTR [58] and TesTra [67] did not report the result." + }, + { + "type": "table", + "bbox": [ + 0.081, + 0.263, + 0.465, + 0.484 + ], + "angle": 0, + "content": "
MethodArchTHUMOS'14TVSeriesHDD
KineticsANetKineticsANetSensor
CDC [45]CNN-44.4---
RED [15]RNN-45.3-79.227.4
TRN [57]RNN62.147.286.283.729.2
IDN [12]RNN60.350.086.184.7-
LAP [34]RNN-53.3-85.3-
PKD [66]CNN64.5-86.4--
WOAD [16]RNN67.1----
OadTR [54]Trans65.258.387.285.429.8
Colar [61]Trans66.959.488.186.030.6
LSTR [58]Trans69.565.389.188.1-
GateHUB [7]Trans70.769.189.688.432.1
TeSTra [67]Trans71.268.2---
MAT (Ours)Trans71.670.489.788.632.7
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.496, + 0.47, + 0.553 + ], + "angle": 0, + "content": "Table 7: Online action detection performances on THUMOS'14 [30], TVSeries [10], and HDD [42]. The mAP performance is reported for THUMOS'14 and HDD, while the mcAP is reported for TVSeries." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.567, + 0.47, + 0.704 + ], + "angle": 0, + "content": "is not suited for short-term memory, as it cannot improve performance and may even degrade the results regarding the verb (32.1% vs 31.0%). However, the model achieves the best performance (19.5%) when performing MixClip and MixClip+ augmentation separately on long- and short-term memory. Moreover, we validate the augmentation of double-MixClip+ (in row 5) on long- and short-term memory and observe that the overall gain of the model is small, similar to double-MixClip (in row 3)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.712, + 0.446, + 0.728 + ], + "angle": 0, + "content": "5.4. Comparison with State-of-the-Art Methods" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Action Anticipation. We compare MAT with prior methods on EPIC-Kitchens-100 for action anticipation, as shown in Table 3. We divide the experimental results into two parts, one part of the input modality is RGB, and the other is multi-modal input, such as optical flow and object features. Using the ImageNet-1K pretrained features, MAT significantly outperforms RULSTM [14], AVT [17], and TeSTra [67] on terms of verb, noun, and action (at least \\(2.5\\%\\), \\(3.0\\%\\), and \\(1.8\\%\\), respectively). MAT with RGB and optical flow features achieves \\(1.8\\%\\) higher action recall than TeSTra with the same input, which can better reflect the ef" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.266, + 0.768, + 0.281 + ], + "angle": 0, + "content": "fectiveness of the modules we designed." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.281, + 0.892, + 0.583 + ], + "angle": 0, + "content": "In Table 4, we conduct an extensive analysis of the impact of various visual encoders on the performance of action anticipation. In particular, we leverage the ViT architecture [11], which is pre-trained on the largest egocentric dataset Ego4D [19], made available by [5], owing to its superior performance in Ego4D Challenges. Additionally, to compare the impact of first-person and third-person pretraining, we utilize the weights pretrained on the K400 [31], provided by VideoMAE [47]. The results suggest that encoders pre-trained on first-person datasets perform better than on widely-used third-person datasets. Moreover, leveraging the noun subset brings a huge performance boost, comparing pretraining on the verb subset of the Ego4D dataset. We suppose the noun subset with more object categories (the verb and noun subset include 118 and 582 categories) encourages the encoder to search more complex visual semantics. It highlights the critical role of egocentric perspective upstream pretraining method [38, 68] and diverse semantic annotations [19, 9, 29], which could have far-reaching implications for egocentric research." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.583, + 0.893, + 0.734 + ], + "angle": 0, + "content": "Following previous works [58, 7, 67], we further evaluate MAT on action anticipation tasks for THUMOS'14 and TVSeries. Unlike the previous work that required additional learnable tokens, we take the corresponding tokens from \\(\\mathbf{F}_A\\) for forecasting. Table 5 shows that using the ActivityNet pretrained features, MAT significantly outperforms the existing methods by \\(2.0\\%\\) and \\(0.6\\%\\) on THUMOS'14 and TVSeries, respectively. Moreover, the performance of MAT can also be further improved when pretraining on Kinetics." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.892, + 0.885 + ], + "angle": 0, + "content": "Online Action Detection. We also compare MAT with other state-of-the-art online action detection methods [57, 58, 54, 61, 7] on THUMOS'14, TVSeries, and HDD. As illustrated in Table 7, our MAT achieves state-of-the-art performance and improves mAP by \\(2.2\\%\\) on the THUMOS'14 dataset under the TSN-Anet feature input, and \\(0.4\\%\\) under the TSN-Kinetics feature. For TVSeries, MAT is slightly better than GateHUB by \\(0.1\\%\\) Furthermore, MAT achieves \\(0.6\\%\\) better than the state-of-the-art GateHUB \\((32.1\\%)\\) method on HDD." + }, + { + "type": "text", + "bbox": [ + 0.52, + 0.886, + 0.892, + 0.901 + ], + "angle": 0, + "content": "To further verify the effect of MAT, in Table 6, we offer" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "13831" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.08, + 0.09, + 0.472, + 0.209 + ], + "angle": 0, + "content": "
Method#ParamFPSmAP
Optical FlowRGB FeatFlow FeatModelTotal
TRN402.9 M8.170.514.6123.38.147.2
OadTR75.8 M8.170.514.6110.08.158.3
LSTR58.0 M8.170.514.691.68.165.3
GateHUB45.2 M8.170.514.671.28.169.1
MAT (Ours)94.6 M8.170.514.672.68.170.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.222, + 0.47, + 0.25 + ], + "angle": 0, + "content": "Table 8: Efficiency comparison between MAT and the previous work on parameter (M) and inference speed (FPS)" + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.264, + 0.472, + 0.34 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.351, + 0.47, + 0.392 + ], + "angle": 0, + "content": "Figure 6: Visualization of MAT's online prediction. The curves indicate the predicted confidence of the ground-truth class (High-Jump) with LSTR and our method." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.41, + 0.47, + 0.593 + ], + "angle": 0, + "content": "the results for online action detection on the EK100 dataset. We divide the experimental results into two parts: one does not use augmentation, and the other uses MixClip or MixClip+. The results show that MAT surpasses the previous method by a large margin whether or not to use data augmentation. It is worth noting that when performing online action detection, we only need to take out the corresponding token in the short-term memory \\(\\widehat{\\mathbf{M}}_S\\) for prediction. The superior performance of the model further highlights that MAT can simultaneously handle online action detection and anticipation tasks, thus integrating the two problems into a unified framework and performing excellently." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.602, + 0.26, + 0.619 + ], + "angle": 0, + "content": "5.5. Efficiency Analysis" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.626, + 0.47, + 0.732 + ], + "angle": 0, + "content": "Table 8 compares MAT with other methods in terms of model parameters and running time, conducted on a single Tesla V100. It is worth noting that under the same features, the efficiency bottleneck of the system remains in optical flow calculation and feature extraction. Our approach achieves a stronger performance while effectively balancing the trade-off between parameters and computational." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.742, + 0.273, + 0.759 + ], + "angle": 0, + "content": "5.6. Qualitative Analysis." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.903 + ], + "angle": 0, + "content": "In Fig 6, we qualitatively analyzes the proposed MAT model. The confidence in the range [0, 1] on the y-axis denotes the probability of predicting the current action, e.g., HighJump. The figure highlights our MAT's successful suppression of background and high-confidence feedback of action segments compared with LSTR. The circular interaction of memory and anticipation provides reliable semantic information for the online prediction of the model, making the model offers a more sensitive and accurate torsion signal" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.09, + 0.894, + 0.258 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.268, + 0.892, + 0.296 + ], + "angle": 0, + "content": "Figure 7: Attention weight visualization of different attention heads." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.315, + 0.858, + 0.33 + ], + "angle": 0, + "content": "on the transition between background and foreground." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.341, + 0.715, + 0.357 + ], + "angle": 0, + "content": "5.7. Attention Visualization" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.365, + 0.894, + 0.456 + ], + "angle": 0, + "content": "Fig 7 depicts the attention weights of the last token of the short-term memory. It can be seen that under the blessing of future perception, MAT's multi-head attention mechanism pays attention to memory and anticipation simultaneously, leading to the model not limiting in history and attaining better performance." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.466, + 0.771, + 0.481 + ], + "angle": 0, + "content": "6. Conclusion and Future Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.491, + 0.893, + 0.779 + ], + "angle": 0, + "content": "We present Memory-and-Anticipation Transformer (MAT), a novel memory-anticipation-based paradigm for online action detection and anticipation, to overcome the weakness of most existing methods that can only complete modeling temporal dependency within a limited historical context. Through extensive experiments on four challenging benchmarks across two tasks, we show its applicability in predicting present or future actions, obtaining state-of-the-art results, and demonstrating the importance of circular interaction between memory and anticipation in the entire temporal structure. Although the temporal dimension is only considered in this work, we believe MAT would be a general paradigm for any AI system used to analyze video online and predict future events. In the near future, we will validate our model on more benchmarks and extend it to the long-term anticipation task. In the longer term, we will continue to unearth the intrinsic association of memory with anticipation and develop more effective forecasting models." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.789, + 0.667, + 0.805 + ], + "angle": 0, + "content": "Acknowledgements" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.894, + 0.9 + ], + "angle": 0, + "content": "This work was supported in part by National Key R&D Program of China (No. 2022ZD0160900), National Natural Science Foundation of China (Grant No. 61672273, 61832008, 62076119), and was also supported by the Fundamental Research Funds for the Central Universities XJ2023000701 and XJ2023004101." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13832" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.468, + 0.157 + ], + "angle": 0, + "content": "[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In ICCV, pages 6816-6826, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.16, + 0.468, + 0.2 + ], + "angle": 0, + "content": "[2] Iz Beltagy, Matthew E. Peters, and Arman Cohan. Longformer: The long-document transformer. CoRR, abs/2004.05150, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.203, + 0.468, + 0.244 + ], + "angle": 0, + "content": "[3] Gedas Bertasius, Heng Wang, and Lorenzo Torresani. Is space-time attention all you need for video understanding? In ICML, volume 139, pages 813-824, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.247, + 0.468, + 0.287 + ], + "angle": 0, + "content": "[4] Shuqiang Cao, Weixin Luo, Bairui Wang, Wei Zhang, and Lin Ma. A circular window-based cascade transformer for online action detection. CoRR, abs/2208.14209, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.291, + 0.468, + 0.386 + ], + "angle": 0, + "content": "[5] Guo Chen, Sen Xing, Zhe Chen, Yi Wang, Kunchang Li, Yizhuo Li, Yi Liu, Jiahao Wang, Yin-Dong Zheng, Bingkun Huang, Zhiyu Zhao, Junting Pan, Yifei Huang, Zun Wang, Jiashuo Yu, Yinan He, Hongjie Zhang, Tong Lu, Yali Wang, Limin Wang, and Yu Qiao. Internvideo-ego4d: A pack of champion solutions to ego4d challenges. CoRR, abs/2211.09529, 2022. 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.389, + 0.468, + 0.456 + ], + "angle": 0, + "content": "[6] Guo Chen, Yin-Dong Zheng, Jiahao Wang, Jilan Xu, Yifei Huang, Junting Pan, Yi Wang, Yali Wang, Yu Qiao, Tong Lu, and Limin Wang. Videollm: Modeling video sequence with large language models. CoRR, abs/2305.13292, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.46, + 0.468, + 0.514 + ], + "angle": 0, + "content": "[7] Junwen Chen, Gaurav Mittal, Ye Yu, Yu Kong, and Mei Chen. Gatehub: Gated history unit with background suppression for online action detection. In CVPR, pages 19925-19934, 2022. 1, 2, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.518, + 0.468, + 0.559 + ], + "angle": 0, + "content": "[8] MMAction2 Contributors. Openmmlab's next generation video understanding toolbox and benchmark. https://github.com/open-mmlab/mmaction2, 2020.5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.562, + 0.468, + 0.657 + ], + "angle": 0, + "content": "[9] Dima Damen, Hazel Doughty, Giovanni Maria Farinella, Antonino Furnari, Jian Ma, Evangelos Kazakos, Davide Moltisanti, Jonathan Munro, Toby Perrett, Will Price, and Michael Wray. Rescaling egocentric vision: Collection, pipeline and challenges for epic-kitchens-100. International Journal of Computer Vision (IJCV), 130:33-55, 2022. 2, 3, 5, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.66, + 0.468, + 0.701 + ], + "angle": 0, + "content": "[10] Roeland De Geest, Efstratios Gavves, Amir Ghodrati, Zhenyang Li, Cees Snoek, and Tinne Tuytelaars. Online action detection. In ECCV, pages 269-284, 2016. 1, 2, 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.704, + 0.468, + 0.813 + ], + "angle": 0, + "content": "[11] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In 9th International Conference on Learning Representations, ICLR 2021, Virtual Event, Austria, May 3-7, 2021. OpenReview.net, 2021. 2, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.816, + 0.468, + 0.869 + ], + "angle": 0, + "content": "[12] Hyunjun Eun, Jinyoung Moon, Jongyoul Park, Chanho Jung, and Changick Kim. Learning to discriminate information for online action detection. In CVPR, pages 806-815, 2020. 2, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.468, + 0.901 + ], + "angle": 0, + "content": "[13] Haoqi Fan, Bo Xiong, Karttikeya Mangalam, Yanghao Li, Zhicheng Yan, Jitendra Malik, and Christoph Feichtenhofer." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.468, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "Multiscale vision transformers. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 6804-6815. IEEE, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.149, + 0.892, + 0.204 + ], + "angle": 0, + "content": "[14] Antonino Furnari and Giovanni Maria Farinella. What would you expect? anticipating egocentric actions with rolling-unrolling lstms and modality attention. In International Conference on Computer Vision (ICCV), 2019. 1, 2, 5, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.206, + 0.892, + 0.245 + ], + "angle": 0, + "content": "[15] Jiyang Gao, Zhenheng Yang, and Ram Nevatia. RED: reinforced encoder-decoder networks for action anticipation. In BMVC, 2017. 2, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.248, + 0.892, + 0.3 + ], + "angle": 0, + "content": "[16] Mingfei Gao, Yingbo Zhou, Ran Xu, Richard Socher, and Caiming Xiong. WOAD: weakly supervised online action detection in untrimmed videos. In CVPR, pages 1915-1923, 2021. 2, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.304, + 0.892, + 0.33 + ], + "angle": 0, + "content": "[17] Rohit Girdhar and Kristen Grauman. Anticipative Video Transformer. In ICCV, 2021. 1, 2, 5, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.333, + 0.892, + 0.413 + ], + "angle": 0, + "content": "[18] Rohit Girdhar, Mannat Singh, Nikhila Ravi, Laurens van der Maaten, Armand Joulin, and Ishan Misra. Omnivore: A single model for many visual modalities. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New Orleans, LA, USA, June 18-24, 2022, pages 16081-16091. IEEE, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.416, + 0.892, + 0.802 + ], + "angle": 0, + "content": "[19] Kristen Grauman, Andrew Westbury, Eugene Byrne, Zachary Chavis, Antonino Furnari, Rohit Girdhar, Jackson Hamburger, Hao Jiang, Miao Liu, Xingyu Liu, Miguel Martin, Tushar Nagarajan, Ilija Radosavovic, Santhosh Kumar Ramakrishnan, Fiona Ryan, Jayant Sharma, Michael Wray, Mengmeng Xu, Eric Zhongcong Xu, Chen Zhao, Siddhant Bansal, Dhruv Batra, Vincent Cartillier, Sean Crane, Tien Do, Morrie Doulaty, Akshay Erapalli, Christoph Feichtenhofer, Adriano Fragomeni, Qichen Fu, Abrham Gebreselasie, Cristina Gonzalez, James Hillis, Xuhua Huang, Yifei Huang, Wenqi Jia, Wesley Khoo, Jachym Kolár, Satwik Kottur, Anurag Kumar, Federico Landini, Chao Li, Yanghao Li, Zhenqiang Li, Karttikeya Mangalam, Raghava Modhugu, Jonathan Munro, Tullie Murrell, Takumi Nishiyasu, Will Price, Paola Ruiz Puentes, Merey Ramazanova, Leda Sari, Kiran Somasundaram, Audrey Southerland, Yusuke Sugano, Ruijie Tao, Minh Vo, Yuchen Wang, Xindi Wu, Takuma Yagi, Ziwei Zhao, Yunyi Zhu, Pablo Arbeláez, David Crandall, Dima Damen, Giovanni Maria Farinella, Christian Fuegen, Bernard Ghanem, Vamsi Krishna Ithapu, C. V. Jawahar, Hanbyul Joo, Kris Kitani, Haizhou Li, Richard A. Newcombe, Aude Oliva, Hyun Soo Park, James M. Rehg, Yoichi Sato, Jianbo Shi, Mike Zheng Shou, Antonio Torralba, Lorenzo Torresani, Mingfei Yan, and Jitendra Malik. Ego4d: Around the world in 3,000 hours of egocentric video. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New Orleans, LA, USA June 18-24, 2022 pages 18973-18990. IEEE, 2022. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.804, + 0.892, + 0.844 + ], + "angle": 0, + "content": "[20] Demis Hassabis, Dharshan Kumaran, Christopher Summerfield, and Matthew Botvinick. Neuroscience-inspired artificial intelligence. Neuron, 95(2):245-258, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.846, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[21] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dólar, and Ross B. Girshick. Masked autoencoders are scalable vision learners. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13833" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.468, + 0.12 + ], + "angle": 0, + "content": "Orleans, LA, USA, June 18-24, 2022, pages 15979-15988. IEEE, 2022. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.121, + 0.469, + 0.162 + ], + "angle": 0, + "content": "[22] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778, 2016. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.163, + 0.469, + 0.219 + ], + "angle": 0, + "content": "[23] Fabian Caba Heilbron, Victor Escorcia, Bernard Ghanem, and Juan Carlos Niebles. Activitynet: A large-scale video benchmark for human activity understanding. In CVPR, pages 961-970, 2015. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.219, + 0.469, + 0.273 + ], + "angle": 0, + "content": "[24] Geoffrey E. Hinton, Nitish Srivastava, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. Improving neural networks by preventing co-adaptation of feature detectors. CoRR, abs/1207.0580, 2012. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.274, + 0.469, + 0.328 + ], + "angle": 0, + "content": "[25] Yifei Huang, Minjie Cai, Zhenqiang Li, Feng Lu, and Yoichi Sato. Mutual context network for jointly estimating egocentric gaze and action. IEEE Transactions on Image Processing, 29:7795-7806, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.33, + 0.469, + 0.398 + ], + "angle": 0, + "content": "[26] Yifei Huang, Minjie Cai, Zhenqiang Li, and Yoichi Sato. Predicting gaze in egocentric video by learning task-dependent attention transition. In Proceedings of the European conference on computer vision (ECCV), pages 754-769, 2018. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.4, + 0.469, + 0.455 + ], + "angle": 0, + "content": "[27] Yifei Huang, Yusuke Sugano, and Yoichi Sato. Improving action segmentation via graph-based temporal reasoning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 14024-14034, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.456, + 0.469, + 0.497 + ], + "angle": 0, + "content": "[28] Yifei Huang, Lijin Yang, and Yoichi Sato. Compound prototype matching for few-shot action recognition. In European Conference on Computer Vision, pages 351-368, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.497, + 0.469, + 0.538 + ], + "angle": 0, + "content": "[29] Baoxiong Jia, Ting Lei, Song-Chun Zhu, and Siyuan Huang. Egotaskqa: Understanding human tasks in egocentric videos. CoRR, abs/2210.03929, 2022. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.539, + 0.469, + 0.594 + ], + "angle": 0, + "content": "[30] Y.-G. Jiang, J. Liu, A. Roshan Zamir, G. Toderici, I. Laptev, M. Shah, and R. Sukthankar. THUMOS challenge: Action recognition with a large number of classes. http://crcv.ucf.edu/THUMOS14/, 2014. 2, 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.595, + 0.469, + 0.663 + ], + "angle": 0, + "content": "[31] Will Kay, João Carreira, Karen Simonyan, Brian Zhang, Chloe Hillier, Sudheendra Vijayanarasimhan, Fabio Viola, Tim Green, Trevor Back, Paul Natsev, Mustafa Suleyman, and Andrew Zisserman. The kinetics human action video dataset. CoRR, abs/1705.06950, 2017. 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.664, + 0.469, + 0.734 + ], + "angle": 0, + "content": "[32] Kris M Kitani, Brian D Ziebart, James Andrew Bagnell, and Martial Hebert. Activity forecasting. In Computer Vision-ECCV 2012: 12th European Conference on Computer Vision, Florence, Italy, October 7-13, 2012, Proceedings, Part IV 12, pages 201-214. Springer, 2012. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.735, + 0.469, + 0.789 + ], + "angle": 0, + "content": "[33] Hema S Koppula and Ashutosh Saxena. Anticipating human activities using object affordances for reactive robotic response. IEEE transactions on pattern analysis and machine intelligence, 38(1):14-29, 2015. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.79, + 0.469, + 0.845 + ], + "angle": 0, + "content": "[34] Sumin Lee, Hyunjun Eun, Jinyoung Moon, Seokeon Choi, Yoonhyung Kim, Chanho Jung, and Changick Kim. Learning to discriminate information for online action detection: Analysis and application. TPAMI, pages 1-17, 2022. 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[35] Kunchang Li, Yali Wang, Yinan He, Yizhuo Li, Yi Wang, Limin Wang, and Yu Qiao. Uniformerv2: Spatiotemporal learning by arming image vits with video uniformer. arXiv preprint arXiv:2211.09552, 2022. 2" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "[36] Kunchang Li, Yali Wang, Yizhuo Li, Yi Wang, Yinan He, Limin Wang, and Yu Qiao. Unmasked teacher: Towards training-efficient video foundation models. arXiv preprint arXiv:2303.16058, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.149, + 0.892, + 0.205 + ], + "angle": 0, + "content": "[37] Zhiqi Li, Zhiding Yu, Wenhai Wang, Anima Anandkumar, Tong Lu, and Jose M Alvarez. Fb-bev: Bev representation from forward-backward view transformations. arXiv preprint arXiv:2308.02236, 2023. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.207, + 0.892, + 0.289 + ], + "angle": 0, + "content": "[38] Kevin Qinghong Lin, Alex Jinpeng Wang, Mattia Soldan, Michael Wray, Rui Yan, Eric Zhongcong Xu, Difei Gao, Rong-Cheng Tu, Wenzhe Zhao, Weijie Kong, Chengfei Cai, Hongfa Wang, Dima Damen, Bernard Ghanem, Wei Liu, and Mike Zheng Shou. Egocentric video-language pretraining. CoRR, abs/2206.01670, 2022. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.291, + 0.892, + 0.332 + ], + "angle": 0, + "content": "[39] Xiaolong Liu, Qimeng Wang, Yao Hu, Xu Tang, Song Bai, and Xiang Bai. End-to-end temporal action detection with transformer. CoRR, abs/2106.10271, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.334, + 0.892, + 0.417 + ], + "angle": 0, + "content": "[40] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 9992-10002. IEEE, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.419, + 0.892, + 0.473 + ], + "angle": 0, + "content": "[41] Giovanni Pezzulo, Francesco Rigoli, and Karl Friston. Active inference, homeostatic regulation and adaptive behavioural control. Progress in neurobiology, 134:17-35, 2015. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.476, + 0.892, + 0.531 + ], + "angle": 0, + "content": "[42] Vasili Ramanishka, Yi-Ting Chen, Teruhisa Mitsu, and Kate Saenko. Toward driving scene understanding: A dataset for learning driver behavior and causal reasoning. In CVPR, 2018. 2, 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.532, + 0.892, + 0.56 + ], + "angle": 0, + "content": "[43] Daniel L Schacter and Donna Rose Addis. The ghosts of past and future. Nature, 445(7123):27-27, 2007. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.562, + 0.892, + 0.659 + ], + "angle": 0, + "content": "[44] Fadime Sener, Dipika Singhania, and Angela Yao. Temporal aggregate representations for long-range video understanding. In Andrea Vedaldi, Horst Bischof, Thomas Brox, and Jan-Michael Frahm, editors, Computer Vision - ECCV 2020 - 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XVI, volume 12361 of Lecture Notes in Computer Science, pages 154-171. Springer, 2020. 1, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.66, + 0.892, + 0.757 + ], + "angle": 0, + "content": "[45] Zheng Shou, Jonathan Chan, Alireza Zareian, Kazuyuki Miyazawa, and Shih-Fu Chang. CDC: convolutional-deconvolutional networks for precise temporal action localization in untrimmed videos. In 2017 IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2017, Honolulu, HI, USA, July 21-26, 2017, pages 1417-1426. IEEE Computer Society, 2017. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.758, + 0.892, + 0.814 + ], + "angle": 0, + "content": "[46] Bilge Soran, Ali Farhadi, and Linda Shapiro. Generating notifications for missing actions: Don't forget to turn the lights off! In Proceedings of the IEEE International Conference on Computer Vision, pages 4669-4677, 2015. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.816, + 0.892, + 0.87 + ], + "angle": 0, + "content": "[47] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. Videomae: Masked autoencoders are data-efficient learners for self-supervised video pre-training. CoRR, abs/2203.12602, 2022. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.872, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[48] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Hervé Jégou. Training" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "13834" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.47, + 0.175 + ], + "angle": 0, + "content": "data-efficient image transformers & distillation through attention. In Marina Meila and Tong Zhang, editors, Proceedings of the 38th International Conference on Machine Learning, ICML 2021, 18-24 July 2021, Virtual Event, volume 139 of Proceedings of Machine Learning Research, pages 10347-10357. PMLR, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.177, + 0.47, + 0.232 + ], + "angle": 0, + "content": "[49] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.233, + 0.471, + 0.288 + ], + "angle": 0, + "content": "[50] Limin Wang, Yuanjun Xiong, Zhe Wang, Yu Qiao, Dahua Lin, Xiaou Tang, and Luc Van Gool. Temporal segment networks: Towards good practices for deep action recognition. In ECCV, pages 20-36, 2016. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.289, + 0.471, + 0.399 + ], + "angle": 0, + "content": "[51] Pichao Wang, Xue Wang, Fan Wang, Ming Lin, Shuning Chang, Hao Li, and Rong Jin. KVT: k-nn attention for boosting vision transformers. In Shai Avidan, Gabriel J. Brostow, Moustapha Cisse, Giovanni Maria Farinella, and Tal Hassner, editors, Computer Vision - ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXIV, volume 13684 of Lecture Notes in Computer Science, pages 285-302. Springer, 2022. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.401, + 0.471, + 0.44 + ], + "angle": 0, + "content": "[52] Sinong Wang, Belinda Z. Li, Madian Khabsa, Han Fang, and Hao Ma. Linformer: Self-attention with linear complexity. CoRR, abs/2006.04768, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.442, + 0.471, + 0.537 + ], + "angle": 0, + "content": "[53] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 548-558. IEEE, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.539, + 0.47, + 0.593 + ], + "angle": 0, + "content": "[54] Xiang Wang, Shiwei Zhang, Zhiwu Qing, Yuanjie Shao, Zhengrong Zuo, Changxin Gao, and Nong Sang. Long short-term transformer for online action detection. In ICCV, 2021. 2, 5, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.595, + 0.471, + 0.663 + ], + "angle": 0, + "content": "[55] Yi Wang, Kunchang Li, Yizhuo Li, Yinan He, Bingkun Huang, Zhiyu Zhao, Hongjie Zhang, Jilan Xu, Yi Liu, Zun Wang, et al. Internvideo: General video foundation models via generative and discriminative learning. arXiv preprint arXiv:2212.03191, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.665, + 0.471, + 0.76 + ], + "angle": 0, + "content": "[56] Chao-Yuan Wu, Yanghao Li, Karttikeya Mangalam, Haoqi Fan, Bo Xiong, Jitendra Malik, and Christoph Feichtenhofer. Memvit: Memory-augmented multiscale vision transformer for efficient long-term video recognition. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New Orleans, LA, USA, June 18-24, 2022, pages 13577-13587. IEEE, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.762, + 0.471, + 0.815 + ], + "angle": 0, + "content": "[57] Mingze Xu, Mingfei Gao, Yi-Ting Chen, Larry S Davis, and David J Crandall. Temporal recurrent networks for online action detection. In ICCV, pages 5532-5541, 2019. 2, 5, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.471, + 0.872 + ], + "angle": 0, + "content": "[58] Mingze Xu, Yuanjun Xiong, Hao Chen, Xinyu Li, Wei Xia, Zhuowen Tu, and Stefano Soatto. Long short-term transformer for online action detection. In NeurIPS, 2021. 1, 2, 3, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.874, + 0.471, + 0.902 + ], + "angle": 0, + "content": "[59] Xinyu Xu, Yong-Lu Li, and Cewu Lu. Learning to anticipate future with dynamic context removal. In Proceedings of" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12734-12744, 2022. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.122, + 0.894, + 0.19 + ], + "angle": 0, + "content": "[60] Antoine Yang, Antoine Miech, Josef Sivic, Ivan Laptev, and Cordelia Schmid. Tubedetr: Spatio-temporal video grounding with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 16442-16453, June 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.192, + 0.892, + 0.234 + ], + "angle": 0, + "content": "[61] Le Yang, Junwei Han, and Dingwen Zhang. Colar: Effective and efficient online action detection by consulting exemplars. In CVPR, 2022. 2, 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.235, + 0.892, + 0.304 + ], + "angle": 0, + "content": "[62] Cunjun Yu, Xiao Ma, Jiawei Ren, Haiyu Zhao, and Shuai Yi. Spatio-temporal graph transformer networks for pedestrian trajectory prediction. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XII 16, pages 507-523. Springer, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.305, + 0.892, + 0.346 + ], + "angle": 0, + "content": "[63] Chen-Lin Zhang, Jianxin Wu, and Yin Li. Actionformer: Localizing moments of actions with transformers. CoRR, abs/2202.07925, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.348, + 0.892, + 0.43 + ], + "angle": 0, + "content": "[64] Hongyi Zhang, Moustapha Cisse, Yann N. Dauphin, and David Lopez-Paz. mixup: Beyond empirical risk minimization. In 6th International Conference on Learning Representations, ICLR 2018, Vancouver, BC, Canada, April 30 - May 3, 2018, Conference Track Proceedings. OpenReview.net, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.432, + 0.892, + 0.488 + ], + "angle": 0, + "content": "[65] Yanyi Zhang, Xinyu Li, Chunhui Liu, Bing Shuai, Yi Zhu, Biagio Brattoli, Hao Chen, Ivan Marsic, and Joseph Tighe. Vidtr: Video transformer without convolutions. In ICCV, pages 13557-13567, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.489, + 0.892, + 0.53 + ], + "angle": 0, + "content": "[66] Peisen Zhao, Jiajie Wang, Lingxi Xie, Ya Zhang, Yanfeng Wang, and Qi Tian. Privileged knowledge distillation for online action detection. CoRR, abs/2011.09158, 2020. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.532, + 0.892, + 0.587 + ], + "angle": 0, + "content": "[67] Yue Zhao and Philipp Krahenbuhl. Real-time online video detection with temporal smoothing transformers. In European Conference on Computer Vision (ECCV), 2022. 1, 2, 3, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.589, + 0.892, + 0.629 + ], + "angle": 0, + "content": "[68] Yue Zhao, Ishan Misra, Philipp Krahenbuhl, and Rohit Girdhar. Learning video representations from large language models. CoRR, abs/2212.04501, 2022. 8" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.894, + 0.629 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13835" + } + ] +] \ No newline at end of file diff --git a/2023/Memory-and-Anticipation Transformer for Online Action Understanding/a1b3a75e-11e3-4ea7-94a7-a5bef15574c1_origin.pdf b/2023/Memory-and-Anticipation Transformer for Online Action Understanding/a1b3a75e-11e3-4ea7-94a7-a5bef15574c1_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..fa51241369c8b57492038944f72bed9ad80136b0 --- /dev/null +++ b/2023/Memory-and-Anticipation Transformer for Online Action Understanding/a1b3a75e-11e3-4ea7-94a7-a5bef15574c1_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:0523a04785004b394508adf1b482075d9a9869aed72cc83e008d71214f9ae184 +size 2182602 diff --git a/2023/Memory-and-Anticipation Transformer for Online Action Understanding/full.md b/2023/Memory-and-Anticipation Transformer for Online Action Understanding/full.md new file mode 100644 index 0000000000000000000000000000000000000000..a510d6cca1d97fd6e08ff11fa67e4d3bf8986df8 --- /dev/null +++ b/2023/Memory-and-Anticipation Transformer for Online Action Understanding/full.md @@ -0,0 +1,347 @@ +# Memory-and-Anticipation Transformer for Online Action Understanding + +Jiahao Wang $^{1*}$ Guo Chen $^{1,2*}$ Yifei Huang $^{2}$ Limin Wang $^{1,2}$ Tong Lu $^{1\boxtimes}$ $^{1}$ State Key Laboratory for Novel Software Technology, Nanjing University + $^{2}$ Shanghai AI Laboratory + +# Abstract + +Most existing forecasting systems are memory-based methods, which attempt to mimic human forecasting ability by employing various memory mechanisms and have progressed in temporal modeling for memory dependency. Nevertheless, an obvious weakness of this paradigm is that it can only model limited historical dependence and can not transcend the past. In this paper, we rethink the temporal dependence of event evolution and propose a novel memory-anticipation-based paradigm to model an entire temporal structure, including the past, present, and future. Based on this idea, we present Memory-and-Anticipation Transformer (MAT), a memory-anticipation-based approach, to address the online action detection and anticipation tasks. In addition, owing to the inherent superiority of MAT, it can process online action detection and anticipation tasks in a unified manner. The proposed MAT model is tested on four challenging benchmarks TVSeries, THUMOS'14, HDD, and EPIC-Kitchens-100, for online action detection and anticipation tasks, and it significantly outperforms all existing methods. Code is available at https://github.com/Echo0125/Memory-and-Anticipation-Transformer. + +# 1. Introduction + +Online anticipation [32] or detection [10] in computer vision attempt to perceive future or present states from a historical perspective. They are the crucial factors of AI systems that engage with complex real environments and interact with other agents, e.g. wearable devices [46], human-robot interaction systems [33], and autonomous vehicles [62]. + +Human beings frequently imagine future events based on past experiences. Similarly, anticipating future events inherently requires modeling past actions or the progression of events to predict what will happen next. To bridge the gap with human forecasting ability, current systems + +![](images/fda5038fd67c3a9bd266960e1d244aff40dc654540c84fad370ae12ca4e16ffa.jpg) +Figure 1: Examples for the forward influence of memory and backward constraint of anticipation. (a) An athlete prepares to start, starts to run, and then jumps to form the result of completing a high jump; (b) The goals of a camera wearer for cutting a tomato dictate the sequence of actions he will perform: hold the knife, get ready to cut, etc.; (c) Compared with the memory-based method, the memory-anticipation-based method is able to establish circular dependencies between memory and future. + +strive to mimic this cognitive ability by employing different memory mechanisms [58, 26, 7, 67, 44, 17]. Previous research [14, 44] demonstrated that modeling long temporal context is crucial for accurate anticipation. LSTR [58] further decomposes the memory encoder into long and short-term stages for online action detection and anticipation, allowing for the extraction of more representative memory features. Similarly, research efforts such as [67, 7, 27] have also illustrated improvements based on this principle. + +However, despite various memory-based approaches, memory is not the only driver of present or future action. The synchronization between shot transitions and the evolution of actor behavior appears to cohere with the beliefs and wills of the event weavers, be they actors or camerewearers. In (a) and (b) of Fig 1, we use the examples of high jumping and cooking to show the forward influence of memory and backward constraint of anticipation. + +Upon closer examination of both examples, it has been observed that future-oriented thoughts may impact action and memory, which seems modulated by the encoding of new information [43, 25]. Additionally, anticipation may change as ongoing behavior progresses and memory is updated [41, 20]. This indicates that there exists a circular interdependence between anticipation and memory, constraining the evolution of behavior or events. + +Based on the preceding analysis, we reevaluate the temporal dependencies inherent in memory-based methods. In their preoccupation with the impact of memory on anticipation, these memory-based methods tend to overlook the inverse direction of impact, i.e., anticipation on memory. Consequently, historical representations are not adequately corrected, thereby risking impeding any attempts to transcend the past. Against this backdrop, we assert that a comprehensive temporal structure seamlessly integrates memory and anticipation is indispensable. In other words, a memory-anticipation-based method building circular dependencies between memory and anticipation, as shown in Fig 1(c), holds tremendous promise for enhancing cognitive inference capabilities and advanced understanding of AI systems about the present and future. + +To this end, we propose Memory-and-Anticipation Transformer (MAT), a novel memory-anticipation-based approach that fully models the complete temporal context, including history, present, and future. A Progressive Memory Encoder is designed to provide a more precise history summary by compressing long- and short-term memory in a segment-based fashion. Meanwhile, we propose our key idea of modeling circular dependencies between memory and future, implemented as Memory-Anticipation Circular Decoder. It first learns latent future features in a supervised manner, then updates iteratively the enhanced short-term memory and the latent future features by performing Conditional circular Interaction between them. Among them, multiple interaction processes capture the circular dependency and supervise the output to maintain stable features with real semantics. + +Remarkably, owing to the inherent superiority of our model design, we are able to adapt both tasks, i.e., online action detection and anticipation, in a unified manner, spanning the training and online inference stages. For any given dataset, the MAT model obviates the need for separate training or testing for each task. Rather, a single training process is enough, and during inference, the corresponding token for each task can be extracted effortlessly. + +In summary, our contributions are 1). We rethink the temporal dependence of event evolution and propose a memory-anticipation-based paradigm for the circular interaction of memory and anticipation, introducing the concept of memory and future circular dependence. 2). We propose a unified architecture Memory-Anticipation Transformer + +(MAT) that simultaneously processes online action detection and anticipation, showing effective performance. 3). MAT significantly outperforms all existing methods on four challenging benchmarks for online action detection and anticipation tasks, i.e., TVSeries [10], THUMOS'14 [30], HDD [42] and EPIC-Kitchens-100 [9]. + +# 2. Related Work + +Online Action Detection and Anticipation. Online action detection [10] aims to predict the action as it happens without accessing the future. Previous methods [57, 12, 16, 61, 54, 58, 7, 67, 4] for online action detection include recurrent networks, reinforcement learning, and, more recently, transformers. [15] uses a reinforced network to encourage making great decisions as early as possible. [57] adopts RNN to generate future predictions to improve online action detection. [58] proposes a transformer to scale the history spanning a longer duration. The target of action anticipation [9, 14, 17, 56] is predicting what actions will occur after a certain time. RULSTM [14] explores action anticipation and proposes an LSTM-based network to solve this problem. AVT [17] proposed an end-to-end attention-based model for anticipative video modeling and learns feature representations by self-supervised methods. + +Online action detection and anticipation share two key characteristics: the inability to perceive future representations, with information derived solely from historical context, and the goal of predicting actions after a certain time. Previous research has typically studied the model for each task in isolation [61, 7] or trained and tested them separately [58, 67], ignoring the potential benefits of leveraging their shared characteristics. We propose a novel unified framework, named MAT, to address this limitation, which allows us to train or infer both tasks simultaneously. + +Transformer for Video Understanding. Transformers have proven successful in natural language processing [49], and researchers have shown increasing interest in its application to vision tasks [11, 48, 40, 53, 18, 37]. Several methods have been proposed to use transformers for temporal modeling in video-related tasks [1, 2, 6, 28, 35, 36, 39, 52, 55, 65]. Timesformer [3] proposes divided attention to capture spatial and temporal information for action recognition separately. MViT [13] builds a feature hierarchy by progressively expanding channel capacity and reducing video spatial-temporal resolution. Actionformer [63] adopts the transformer architecture with local attention for temporal action localization. TubeDETR [60] tackles video grounding with an encoder-decoder transformer-based architecture to efficiently encode spatial and multi-modal interactions. Our MAT model is also built upon the transformer, utilizing its encoder and decoder architectures. We meticulously integrate the transformer blocks to implement our memory encoder and memory-anticipation circular decoder. + +![](images/84096c7762465264f596457b38a592b26977a4f3d7eeb453f581268434854c36.jpg) +Progressive Memory Encoder +Memory-Anticipation Circular Decoder +Figure 2: MAT architecture. We first divide the temporal sequence into long-term and short-term memories. In Progressive Memory Encoder, long-term memory queries $\mathbf{Q}_L$ progressively map the long-term to an abstract representation and be fed to the transformer decoder block to enhance the short-term memory. Then the Memory-Anticipation Circular Decoder utilizes learnable queries $\mathbf{Q}_F$ and $\mathbf{Q}_F'$ to perceive the future context and circularly updates the historical and future representation. Finally, a weight-shared classifier is adopted to output the classification scores of short-term and future for online action detection and anticipation. + +# 3. Problem Setup + +Online action anticipation and detection share a similar goal of predicting actions in untrimmed video sequences. In the former, we aim to forecast actions after a time gap $\tau$ , as defined in [9], while in the latter, we predict the action under $\tau = 0$ . Both tasks require classifying actions without access to future information during inference. We represent the input video as $\mathbf{V} = \{v_t\}_{t = -T + 1}^0$ , and our objective is to predict the action category $\tilde{y}_{\tau} \in \{0,1,2,\dots,C\}$ occurs after a specified time gap $\tau$ in the future. Here, $C$ represents the total number of action categories, and label 0 denotes the background category. + +# 4. Memory-and-Anticipation Transformer + +We now describe Memory-and-Anticipation Transformer (MAT) model architecture, as illustrated in Fig 2. It processes the memory cached in runtime to predict current or future actions. We adopt the encoder-decoder architecture to implement the model. The Progressive Memory Encoder is proposed to improve the quality of compressing long-term memory and enhancing short-term memory, which has a fundamental impact on anticipation and detection. MAT also employs our presented key component Memory-Anticipation Circular Decoder that generates the latent anticipation feature and conducts interaction between memory and anticipation in an iterative loop. We now introduce each model component in detail, followed by the training, online inference, and implementation details. + +# 4.1. Progressive Memory Encoder + +We use video feature $\mathbf{F} = \{f_t\}_{t = -T + 1}^0\in \mathbb{R}^{T\times D}$ generated by a pretrained feature extractor as the input to our model, where $D$ and $T$ are the dimension and length of the feature sequence, respectively. To better handle the long memory, following [58], we divide the feature sequence into + +two consecutive memories. The first is the short-term memory that stores only a handful of recently occurred frames. It stores the feature vectors as $\mathbf{M}_S = \{f_t\}_{t = -m_S + 1}^0$ , where $m_{S}$ denotes the length. The other, named long-term memory, contains the feature that is far away from the current time, which is defined as $\mathbf{M}_L = \{f_t\}_{t = -T + 1}^{-m_S}$ . We set $m_{L}$ to be the length of the long-term memory, which is much longer than the short-term memory. + +In practice, Progressive Memory Encoder progressively encodes long- and short-term memories. It first compresses the long-term memory to an abstract representation and injects them into the short-term memory. Differing with previous works [58, 67] that separately tackle the long- and short-term memories by one long-term encoder and one short-term decoder, we integrate these two works into a single encoder architecture. It is due to our encoded short-term memory being served for decoders and not as the final output. In our experiments, we observe that the design of the memory encoder is crucial for model performance. Therefore, different with [58, 67], we introduce a novel long-term memory compression method to improve the quality of memory encoding. + +Segment-based Long-term Memory Compression. LSTR [58] adopts a two-stage compression technique to project the long-term memory to a fixed-length latent embedding. It implements a function similar to the bottleneck layer [22]. Long-term memory, however, represents a long token sequence that often carries much noise. It is problematic to generate attention weights while crossattention queries too many tokens with mixed noise. We propose Segment-based Long-term Memory Compression to alleviate the issue, as shown in Fig 3. Concretely, we first divide $\mathbf{M}_L$ into $N_{s}$ non-overlapping memory segments $\mathbf{S} = \{\mathbf{s}_i\}_{i = 1}^{N_s}$ of length $\frac{m_L}{N_s}$ . We then employ $N_{L}$ learnable tokens $\mathbf{Q}_L\in \mathbb{R}^{N_L\times D}$ as the long-term memory queries and a weight-shared transformer decoder block to query + +each segment. $\mathbf{S}$ will be transformed to $N_{s}$ segment-level abstract feature $\mathbf{F} = \{\mathbf{f}_i\}_{i = 1}^{N_s}$ , where $\mathbf{f}_i\in \mathbb{R}^{N_L\times D}$ . We average pool each $\mathbf{f}_i$ to one vector $\mathbb{R}^D$ and concatenate them to form the long-term compressed segmented memory $\mathbf{M}_L^s\in \mathbb{R}^{N_s\times D}$ . At last, we feed them into two transformer encoder blocks to obtain the final compressed longterm memory $\widehat{\mathbf{M}}_L\in \mathbb{R}^{N_s\times D}$ . + +Short-term Memory Enhancement. As short-term memory $\mathbf{M}_S = \{f_t\}_{t = -m_S + 1}^0$ contains crucial trends for accurately predicting the current or upcoming activities, we leverage short-term memory as the query to retrieve relevant context from the compressed long-term memory. As illustrated in Fig 2, we employ a transformer causal decoder block to aggregate compressed long-term memory $\widehat{\mathbf{M}}_L$ into short-term memory. The enhanced short-term memory $\widehat{\mathbf{M}}_S$ is then used to identify actions at each timestep, constituting a sequence of previously occurring actions and predicting future states and actions. We use frame-level action labels to supervise the dense classification task, encouraging the model to produce a clear sequence of historical behavior. + +# 4.2. Memory-Anticipation Circular Decoder + +To implement our key idea that considers the co-reaction between anticipation and memory, we carefully design Memory-Anticipation Circular Decoder that circularly performs interaction between them. It first generates the latent anticipation that is a prerequisite for memory-anticipation interaction. Then, Conditional Circular Interaction will generate new memories and anticipation conditioned on old ones iteratively. Finally, a weight-shared classification head will supervise the generated memories and anticipation. + +Latent Anticipation Generation. Initially, we do not have an anticipation state. Therefore, we must first generate a latent anticipation feature, i.e., a future representation containing abstract information derived from known memory. Given the compressed long-term memory $\widehat{\mathbf{M}}_L$ and short-term memory $\widehat{\mathbf{M}}_S$ , we first concatenate them to form the entire memory $\mathbf{M}_E = [\widehat{\mathbf{M}}_L, \widehat{\mathbf{M}}_S]$ , where $[\cdot, \cdot]$ is the concatenating operation along the temporal dimension. Then, we use $N_F$ future queries $\mathbf{Q}_F \in \mathbb{R}^{N_F \times D}$ and a transformer decoder block to query $\mathbf{M}_E$ . The updated future queries are represented as the latent anticipation features $\mathbf{F}_A \in \mathbb{R}^{N_F \times D}$ at the current state. We use future information, e.g., future video features and future action labels, to supervise $\mathbf{F}_A$ . In practice, we use information from the next $T_F$ seconds. Since $\mathbf{F}_A$ is only used to describe the latent future states, too large future embeddings may overfit the anticipation representation. We set $N_F$ to be smaller than the length of the used future information sequence. Then we use bilinear interpolation to upsample it to align for point-to-point supervision. Note that although we use future information here, this does not lead to an information leak. The model will generate preliminary anticipation + +![](images/cf0bbbf71d6b4c46b1bd735c217ba1258943f1d92de9b2a59da2728a1ae4d20f.jpg) +Figure 3: Segment-based Long-term Memory Compression. For example, given $m_{L} = 9$ , $N_{s} = 3$ , the process is shown above. We can finally obtain compressed features $\widehat{M}_L$ of length 3. + +in the inference phase and not use future labels or features. + +Conditional Circular Interaction. So far, we have generated long-term memory $\widehat{\mathbf{M}}_L$ , short-term memory $\widehat{\mathbf{M}}_S$ and latent anticipation features $\mathbf{F}_A$ . The memories, however, are limited to the past and can not go beyond history. We now describe how Conditional Circular Interaction works. For brevity, we detail how memory and anticipation interact with each other one time. + +As shown in Fig 4, we first concatenate $\widehat{\mathbf{M}}_L$ , $\widehat{\mathbf{M}}_S$ and $\mathbf{F}_A$ to form the entire feature $\mathbf{F}_E = [\widehat{\mathbf{M}}_L, \widehat{\mathbf{M}}_S, \mathbf{F}_A]$ . Then, $\mathbf{F}_E$ and $\widehat{\mathbf{M}}_S$ are feed into a transformer decoder block: + +$$ +\widehat {\mathbf {M}} _ {S} ^ {\prime} = \operatorname {C r o s s A t t n} \left(\widehat {\mathbf {M}} _ {S}, \mathbf {F} _ {E}, \mathbf {F} _ {E}\right), \tag {1} +$$ + +where $\mathrm{CrossAttn}(Q,K,V)$ is the cross-attention layer in the transformer decoder block. The updated short-term memory is represented as $\widehat{\mathbf{M}}_S^{\prime}$ . Since $\mathbf{F}_E$ contains memories and anticipation, $\widehat{\mathbf{M}}_S$ as a query condition dynamically extracts new semantics mixed with memories and anticipation from three representations. Next, we re-concatenate $\widehat{\mathbf{M}}_L$ , $\widehat{\mathbf{M}}_S^{\prime}$ and $\mathbf{F}_A$ to generate the new entire feature $\mathbf{F}_E^{\prime} = [\widehat{\mathbf{M}}_L,\widehat{\mathbf{M}}_S^{\prime},\mathbf{F}_A]$ . Another transformer decoder block is used to query $\mathbf{F}_E^{\prime}$ , with $\mathbf{F}_A$ as the query condition: + +$$ +\mathbf {F} _ {A} ^ {\prime} = \operatorname {C r o s s A t t n} \left(\mathbf {F} _ {A}, \mathbf {F} _ {E} ^ {\prime}, \mathbf {F} _ {E} ^ {\prime}\right), \tag {2} +$$ + +where $\mathbf{F}_A^\prime$ is the resulting anticipation features. After that, $\mathbf{F}_A^\prime$ is injected with the higher-order inferred semantics brought about by the interaction between memory and anticipation. + +In the interaction process, the generated $\widehat{\mathbf{M}}_S^{\prime}$ is both supervised like the above initial anticipation features. It should be noted that different from generating latent initial anticipation through fewer future queries, we find that using a new group of future queries $\mathbf{Q}_F^{\prime} \in \mathbb{R}^{N_F^{\prime} \times D}$ strictly aligned future information sequences of $T_{F}$ seconds in the first interaction process to replace the $\mathbf{F}_A$ with $\mathbf{Q}_F^{\prime}$ , bring + +![](images/7fe50402cc49b9a7ca248989783fbd5f5eff4f00abb59eea7fef14c4a3887e7f.jpg) +Figure 4: Conditional circular interaction dynamically updates and re-constructs the context between memories and anticipation by aggregating different temporal information. + +performance improvement. Thus, we point-to-point supervise the anticipation $\mathbf{F}_A^\prime$ generated by each interaction process. Meanwhile, this design is more natural to output the corresponding token according to the anticipation gap time. We circularly perform the interaction process $N_{t}$ times until saturation. The yielded $\widehat{\mathbf{M}}_S^{\prime}$ and $\mathbf{F}_A^\prime$ in one interaction process become the new $\widehat{\mathbf{M}}_S$ and $\mathbf{F}_A$ and are passed to the next interaction process. + +# 4.3. Training + +Our MAT model relies on action steps of short-term memory to predict the current or future action. These steps are utilized as auxiliary information to benefit action detection and anticipation. It is worth noting that since the MAT model regards online action detection and anticipation as the same tasks with different settings, we can define the loss function in a unified fashion. + +For the $\widehat{\mathbf{M}}_S$ generated by the encoder, we feed it to a classifier to generate the action probabilities $\widehat{\mathbf{Y}}_S = \{\widehat{\mathbf{y}}_S^i\}_{i=1}^{m_S}$ . We then supervise the whole short-term memory using a cross-entropy loss with the labeled action, $\{c_S^i\}_{i=1}^{m_S}$ . Learned future features $\mathbf{F}_A$ are fed into the same classifier to generate the probabilities $\widehat{\mathbf{Y}}_F = \{\widehat{\mathbf{y}}_F^i\}_{i=1}^{N_F}$ and we also adopt a cross-entropy loss with the target, $\{c_F^i\}_{i=1}^{m_S}$ : + +$$ +\mathcal {L} _ {S} ^ {0} = - \sum_ {i = 1} ^ {m _ {S}} \log \widehat {\mathbf {y}} _ {S} ^ {i} [ c _ {S} ^ {i} ], \mathcal {L} _ {F} ^ {0} = - \sum_ {i = 1} ^ {N _ {F}} \log \widehat {\mathbf {y}} _ {F} ^ {i} [ c _ {F} ^ {i} ], \tag {3} +$$ + +where $\mathcal{L}_S^0$ and $\mathcal{L}_F^0$ are the loss function of encoded shortterm memory and initial anticipation features, respectively. As the conditional circular interaction is conducted $N_{t}$ times, we use $\mathcal{L}_S^i$ and $\mathcal{L}_F^i$ to represent the loss of memory and anticipation in each interaction process, where $1\leq i\leq N_{t}$ . Their calculation is similar to $\mathcal{L}_S^0$ and $\mathcal{L}_F^0$ . The final training loss is formulated by: + +$$ +\mathcal {L} = \sum_ {i = 0} ^ {N _ {t}} \lambda_ {s} ^ {i} \cdot \mathcal {L} _ {S} ^ {i} + \lambda_ {f} \sum_ {i = 0} ^ {N _ {t}} \mathcal {L} _ {F} ^ {i}, \tag {4} +$$ + +where $\lambda_s^i$ and $\lambda_{f}$ are the balance coefficients. + +# 4.4. Online Inference + +The existing works [57, 61, 58, 67, 17] test each task independently. Thanks to the design of the unified framework, MAT simultaneously infers online action detection and anticipation tasks on one streaming video. It uses the output $\widehat{\mathbf{M}}_S$ and $\mathbf{F}_A$ produced by the last interaction as results of online action detection and anticipation, respectively. We take out the last token of $\widehat{\mathbf{M}}_S$ for online action detection. For action anticipation, according to gap time $\tau$ , we take out the corresponding token from $\mathbf{F}_A$ for forecasting. + +# 5. Experiments + +# 5.1. Dataset and Metrics + +Dataset. We test on three online action detection datasets. THUMOS'14 [30] consists of over 20 hours of sports video annotated with 20 actions. TVSeries [10] includes 27 episodes of 6 popular TV series, about 150 minutes each and 16 hours total. HDD [42] is a largescale human driving video dataset comprising 104 hours of untrimmed videos and 11 action categories. Furthermore, we evaluate on EpicKitchens-100 [9] that contains 100 hours of egocentric videos with at least 90K action segments and whose narrations are mapped to 97 verb classes and 300 noun classes. + +Evaluation Metrics. For online action detection, following previous works [10, 34, 54, 58, 61], we use per-frame mean Average Precision (mAP) on THUMOS'14 and HDD, and per-frame mean calibrated Average Precision (mcAP) [10] on TVSeries. For action anticipation, we employ Top-5 Verb/Noun/Action Recall to measure the performance with an anticipation period $\tau = 1s$ [9]. + +# 5.2. Implementation details + +Following prior works [57, 58, 67], we conduct our experiments on pre-extracted features. For TVSeries and THUMOS'14, we first resample the videos at 24 FPS and then extract the frames at 4 FPS for training and validation. We adopt a two-stream network [50] to extract feature. We use off-the-shell checkpoint released by mmentation2 [8] that pretrained on ActivityNet v1.3 [23] and Kinetics [31] to extract frame-level RGB and optical features. On EK100, following [14], we resample the videos at 30 FPS and then fine-tune the two-stream TSN on the classification task. + +Memory Dropping. Despite the promising capabilities of the dense attention mechanism, capturing long-range dependencies remains a challenge. However, relying on the dense attention mechanism may lead to sub-optimization of the network, resulting in a locally optimal solution. We seek to explore memory-dropping strategies for implementing sparse attention during training. We experiment with various approaches, including dropout [24], top-k selec + +
NsmAP
[58]69.6
269.8
470.2
870.4
1270.1
+ +(a) Segment number. + +
renewalmAP
070.0
170.4
269.7
+ +
deepsupervisionmAP
-cls69.9
✓feat69.6
✓cls70.4
✓feat + cls70.2
+ +(b) Future queries renewing. + +
shortfuturemAP
unshared69.6
separately shared70.1
full shared70.4
+ +(c) Future supervision. + +
longshortVNA
--32.136.118.1
MC-32.936.918.4
MCMC31.037.418.5
MCMC+35.038.819.5
MC+MC+31.636.818.4
+ +(d) Shared classifier. +(e) MixClip+. + +Table 1: Ablation Experiments. We conduct detailed ablation on (a): Segment number, (b): Future queries renewing, (c): Future supervision, (d): Shared classifier, and (e): MixClip+. The gray rows denote default choices. +long short future interaction $N_{t}$ detection anticipation + +
(a)--67.6+0.053.7+0.0
(b)✓CA168.3+0.754.7+1.0
(c)✓✓CA168.9+1.355.3+1.6
(d)✓✓CA168.6+1.055.8+2.1
(e)✓✓CA169.2+1.656.1+2.4
(f)✓✓✓Avg&Cat168.3+0.755.3+1.6
(g)✓✓✓CA169.9+2.356.6+2.9
(h)✓✓✓CA270.4+2.957.3+3.6
(i)✓✓✓CA370.2+2.657.1+3.4
+ +Table 2: Ablation study on the information stream, interaction method, and times for Conditional Circular Interaction. The shallow gray row denotes the baseline setting without any interaction. + +tion [51], and token dropping [21]. We compare these strategies, recorded in the supplementary material, and find that the top-k selection yields the best performance. + +MixClip+. TesTra [67] proposed an augmentation technique called MixClip to solve over-fitting caused by large long-term memory. Unlike long-term memory which presents an abstract concept, short-term memory provides a continuous motion trend, often playing a decisive role in anticipation. It leads to the fact that MixClip damages the continuity of motion, thereby, does not apply to short-term memory. We propose MixClip+ to solve the issue. + +In addition to mixing augmentation for long-term memory, we mix each feature token of short-term memory with a random clip from different videos. To maintain the continuity of short-term memory, we adopt soft fusion with hyperparameter $\alpha = 0.25$ to mix features and the corresponding labels, similar to Mixup [64]. Due to space limitations, we will describe this part in the supplementary material. + +# 5.3. Ablation Study + +Now we analyze the MAT model, using the two-stream features pretrained on ActivityNet v1.3 and THUMOS'14 test set as the test bed. Furthermore, we also study the contribution of the proposed MixClip+ on EPIC-Kitchens-100. + +Segment Number. We evaluate the effect of segment number $N_{s}$ for long-term memory compression in Table 1a. We find even a small $N_{s}$ can improve performance, com + +![](images/ffbb725d7783c022603e6a70b4e982b6c1d6ed63f69633601c8feb82760f765a.jpg) +Figure 5: Generating latent anticipation with different anticipation length $T_{F}$ and numbers of learnable tokens $N_{F}$ . + +pared with two-stage compression [58]. However, too many segments result in too little information within each segment to effectively capture temporal dependency. We use $N_{s} = 8$ as the default in the following ablation experiments. + +Query Number and Anticipation Length. Fig 5 compares generating latent anticipation using $N_{F}$ learnable tokens with different anticipation lengths $T_{F}$ . The experimental results indicate that, for $T_{F} \leq 4$ , a larger $N_{F}$ yields superior results owing to strongly correlated semantics of short-term memory and short-term anticipation thus, the model can benefit from more tokens. We observe that $N_{F} = 8,16,32$ exhibits a similar trend in the accuracy curve, with the model achieving optimal performance with $N_{F} = 32$ . This suggests that long-term anticipation is more adaptable for sparse tokens. The observations imply that anticipation is also suitable for long- and short-term modeling. + +Future Queries Renewal. As Section 4.2 outlines, renewing future queries before the initial interaction improves performance. In Table 1b, we compare different renewing times ("0" denotes no renewal and utilizes $F_{A}$ ). A plausible explanation is that, in the first interaction process, the interaction from anticipation to memory adjusts the old memory, causing its domain to shift largely, which leads to insufficient interaction from the new memory to the initial anticipation feature. + +Future Supervision. In addition, we carry out diverse experiments to determine the optimal choice of future su + +
MethodModalityInitOverallUnseenTail
VerbNounActionVerbNounActionVerbNounAction
RULSTM [14]RGBIN-1K27.529.013.329.823.813.119.921.410.6
AVT [17]IN-1K27.230.713.6------
AVT [17]IN-21K30.231.714.9------
DCR [59]IN-1K31.031.114.6------
TeSTra [67]IN-1K26.836.217.027.130.113.319.328.613.7
MAT (Ours)IN-1K32.739.718.831.732.112.725.732.416.0
RULSTM [14]RGB + OF + OBJIN-1K27.830.814.028.827.214.219.822.011.1
TempAgg [44]IN-1K23.231.414.728.026.214.514.522.514.8
AVT+ [17]IN-1K25.531.814.825.523.611.518.525.812.6
AVT+ [17]IN-21K28.232.015.929.526.012.823.229.214.1
TeSTra [67]RGB + OFIN-1K30.835.817.629.626.012.823.229.214.2
MAT (Ours)IN-1K35.038.819.532.530.313.828.733.116.9
+ +Table 3: Comparison to prior work on EPIC-Kitchens-100 Action Anticipation [9]. Accuracy measured by class-mean recall@5(%) following the standard protocol. + +
ModalityEncoderInitFTOverallUnseenTail
RGBTSNIN-1K✓18.812.716.0
RGB + OFTSNIN-1K✓19.513.816.9
RGBViT-LK40019.116.216.1
RGB (V)ViT-LEgo4D21.919.418.5
RGB (N)ViT-LEgo4D24.221.420.9
RGB (V + N)ViT-LEgo4D24.621.421.2
+ +persion, as illustrated in Table 1c. We investigate two methods, namely future feature supervision and future label supervision. The results suggest that, compared to feature supervision, label supervision yields superior accuracy by incorporating stronger semantics derived from manual annotation. Furthermore, we explore the significance of deep supervision, i.e., multi-stage supervision. We observe that introducing multiple supervisions of real action labels improves performance. + +Shared Classifier. In Table 1d, we exploit the classifier design in deep supervision for short-term memory and anticipation. We observe that sharing classifier parameters separately for them yields better performance. When we use a full-shared classifier for memory and anticipation, sharing all feature samples between them leads to the best performance. These results indicate that all yielded features in the interaction processes enrich the feature samples to be classified, reaching a function similar to the data augmentation. + +Conditional Circular Interaction. Table 2 compares conditional circular interaction incorporating different interaction information streams, methods, and times. From (a) to (e), our experimental results demonstrate that the model's classification performance improves with the in + +Table 4: Exploring different visual encoders for EK100 action anticipation. V or N denotes the encoder is pretrained on verb or noun subset [5]. "FT" is that the encoder is fine-tuned on the classification task of EK100. + +
MethodTHUMOS'14TVSeries
KineticsANetKineticsANet
RED [15]-37.575.1-
TRN [57]-38.975.7-
OadTR [54]53.545.977.879.1
LSTR [58]52.650.180.8-
GateHUB [7]-54.282.0-
TesTra [67]56.855.3--
MAT (ours)58.257.382.681.5
+ +Table 5: Action anticipation result on THUMOS'14 and TVSeries, mAP is reported for THUMOS'14 and mcAP for TVSeries. + +creasing richness of interaction information. Moreover, we observe that latent information in the future is equally or even more critical to classify the current action than information from the distant past, as evidenced by the performance comparison between (c) and (e). We also investigate the effect of different interaction mechanisms, comparing (f) and (g), and the results indicate that the cross-attention (CA) mechanism outperforms average pooling and concatenation similar to [54], achieving a $2.1\%$ higher accuracy. Lastly, we evaluate the impact of different interaction times $N_{t}$ , as illustrated by (g), (h), and (i). The experimental results reveal that the model's performance improves gradually with the increase of $N_{t}$ . Notably, the model attains its highest performance when interacting with all information $N_{t} = 2$ times. + +MixClip+ for Anticipation. Table 1e presents the augmentation efficacy of MixClip+ or MixClip on long- and short-term memory. Notably, the baseline experiences a significant drop in action recall to $18.1\%$ without data augmentation. However, the result is still significantly better than Testra [67] with MixClip ( $18.1\%$ vs $17.6\%$ ), as shown in Table 3. Furthermore, the results in row 3 reveal that MixClip + +
MethodAugmentationOverallUnseenTail
LongShortVerbNounActionVerbNounActionVerbNounAction
LSTR‡[58]--39.644.122.634.335.318.739.041.620.7
TesTra‡[67]--40.044.823.234.636.019.039.442.120.9
MAT (ours)--41.846.124.936.537.920.140.843.222.8
TesTra‡[67]MixClip-39.745.625.136.337.219.239.042.422.2
MAT (ours)MixClip-42.647.325.938.337.619.741.844.023.1
MAT (ours)MixClipMixClip+44.548.326.339.938.120.343.446.623.7
+ +Table 6: Online action detection result on EPIC-Kitchens-100. Accuracy is measured by class-mean recall@5%. ‡ was reproduced by us because LSTR [58] and TesTra [67] did not report the result. + +
MethodArchTHUMOS'14TVSeriesHDD
KineticsANetKineticsANetSensor
CDC [45]CNN-44.4---
RED [15]RNN-45.3-79.227.4
TRN [57]RNN62.147.286.283.729.2
IDN [12]RNN60.350.086.184.7-
LAP [34]RNN-53.3-85.3-
PKD [66]CNN64.5-86.4--
WOAD [16]RNN67.1----
OadTR [54]Trans65.258.387.285.429.8
Colar [61]Trans66.959.488.186.030.6
LSTR [58]Trans69.565.389.188.1-
GateHUB [7]Trans70.769.189.688.432.1
TeSTra [67]Trans71.268.2---
MAT (Ours)Trans71.670.489.788.632.7
+ +Table 7: Online action detection performances on THUMOS'14 [30], TVSeries [10], and HDD [42]. The mAP performance is reported for THUMOS'14 and HDD, while the mcAP is reported for TVSeries. + +is not suited for short-term memory, as it cannot improve performance and may even degrade the results regarding the verb (32.1% vs 31.0%). However, the model achieves the best performance (19.5%) when performing MixClip and MixClip+ augmentation separately on long- and short-term memory. Moreover, we validate the augmentation of double-MixClip+ (in row 5) on long- and short-term memory and observe that the overall gain of the model is small, similar to double-MixClip (in row 3). + +# 5.4. Comparison with State-of-the-Art Methods + +Action Anticipation. We compare MAT with prior methods on EPIC-Kitchens-100 for action anticipation, as shown in Table 3. We divide the experimental results into two parts, one part of the input modality is RGB, and the other is multi-modal input, such as optical flow and object features. Using the ImageNet-1K pretrained features, MAT significantly outperforms RULSTM [14], AVT [17], and TeSTra [67] on terms of verb, noun, and action (at least $2.5\%$ , $3.0\%$ , and $1.8\%$ , respectively). MAT with RGB and optical flow features achieves $1.8\%$ higher action recall than TeSTra with the same input, which can better reflect the ef + +fectiveness of the modules we designed. + +In Table 4, we conduct an extensive analysis of the impact of various visual encoders on the performance of action anticipation. In particular, we leverage the ViT architecture [11], which is pre-trained on the largest egocentric dataset Ego4D [19], made available by [5], owing to its superior performance in Ego4D Challenges. Additionally, to compare the impact of first-person and third-person pretraining, we utilize the weights pretrained on the K400 [31], provided by VideoMAE [47]. The results suggest that encoders pre-trained on first-person datasets perform better than on widely-used third-person datasets. Moreover, leveraging the noun subset brings a huge performance boost, comparing pretraining on the verb subset of the Ego4D dataset. We suppose the noun subset with more object categories (the verb and noun subset include 118 and 582 categories) encourages the encoder to search more complex visual semantics. It highlights the critical role of egocentric perspective upstream pretraining method [38, 68] and diverse semantic annotations [19, 9, 29], which could have far-reaching implications for egocentric research. + +Following previous works [58, 7, 67], we further evaluate MAT on action anticipation tasks for THUMOS'14 and TVSeries. Unlike the previous work that required additional learnable tokens, we take the corresponding tokens from $\mathbf{F}_A$ for forecasting. Table 5 shows that using the ActivityNet pretrained features, MAT significantly outperforms the existing methods by $2.0\%$ and $0.6\%$ on THUMOS'14 and TVSeries, respectively. Moreover, the performance of MAT can also be further improved when pretraining on Kinetics. + +Online Action Detection. We also compare MAT with other state-of-the-art online action detection methods [57, 58, 54, 61, 7] on THUMOS'14, TVSeries, and HDD. As illustrated in Table 7, our MAT achieves state-of-the-art performance and improves mAP by $2.2\%$ on the THUMOS'14 dataset under the TSN-Anet feature input, and $0.4\%$ under the TSN-Kinetics feature. For TVSeries, MAT is slightly better than GateHUB by $0.1\%$ Furthermore, MAT achieves $0.6\%$ better than the state-of-the-art GateHUB $(32.1\%)$ method on HDD. + +To further verify the effect of MAT, in Table 6, we offer + +
Method#ParamFPSmAP
Optical FlowRGB FeatFlow FeatModelTotal
TRN402.9 M8.170.514.6123.38.147.2
OadTR75.8 M8.170.514.6110.08.158.3
LSTR58.0 M8.170.514.691.68.165.3
GateHUB45.2 M8.170.514.671.28.169.1
MAT (Ours)94.6 M8.170.514.672.68.170.4
+ +Table 8: Efficiency comparison between MAT and the previous work on parameter (M) and inference speed (FPS) + +![](images/5e6aabeedaa545e85a5a2cd69515be16a1599679ee3ea7ca1d29ae19eb8414ba.jpg) +Figure 6: Visualization of MAT's online prediction. The curves indicate the predicted confidence of the ground-truth class (High-Jump) with LSTR and our method. + +the results for online action detection on the EK100 dataset. We divide the experimental results into two parts: one does not use augmentation, and the other uses MixClip or MixClip+. The results show that MAT surpasses the previous method by a large margin whether or not to use data augmentation. It is worth noting that when performing online action detection, we only need to take out the corresponding token in the short-term memory $\widehat{\mathbf{M}}_S$ for prediction. The superior performance of the model further highlights that MAT can simultaneously handle online action detection and anticipation tasks, thus integrating the two problems into a unified framework and performing excellently. + +# 5.5. Efficiency Analysis + +Table 8 compares MAT with other methods in terms of model parameters and running time, conducted on a single Tesla V100. It is worth noting that under the same features, the efficiency bottleneck of the system remains in optical flow calculation and feature extraction. Our approach achieves a stronger performance while effectively balancing the trade-off between parameters and computational. + +# 5.6. Qualitative Analysis. + +In Fig 6, we qualitatively analyzes the proposed MAT model. The confidence in the range [0, 1] on the y-axis denotes the probability of predicting the current action, e.g., HighJump. The figure highlights our MAT's successful suppression of background and high-confidence feedback of action segments compared with LSTR. The circular interaction of memory and anticipation provides reliable semantic information for the online prediction of the model, making the model offers a more sensitive and accurate torsion signal + +![](images/ec9224486ed73be0889e595d38aa06b1ac67a43bb56a49cf53b8009e9a8c9410.jpg) +Figure 7: Attention weight visualization of different attention heads. + +on the transition between background and foreground. + +# 5.7. Attention Visualization + +Fig 7 depicts the attention weights of the last token of the short-term memory. It can be seen that under the blessing of future perception, MAT's multi-head attention mechanism pays attention to memory and anticipation simultaneously, leading to the model not limiting in history and attaining better performance. + +# 6. Conclusion and Future Work + +We present Memory-and-Anticipation Transformer (MAT), a novel memory-anticipation-based paradigm for online action detection and anticipation, to overcome the weakness of most existing methods that can only complete modeling temporal dependency within a limited historical context. Through extensive experiments on four challenging benchmarks across two tasks, we show its applicability in predicting present or future actions, obtaining state-of-the-art results, and demonstrating the importance of circular interaction between memory and anticipation in the entire temporal structure. Although the temporal dimension is only considered in this work, we believe MAT would be a general paradigm for any AI system used to analyze video online and predict future events. In the near future, we will validate our model on more benchmarks and extend it to the long-term anticipation task. In the longer term, we will continue to unearth the intrinsic association of memory with anticipation and develop more effective forecasting models. + +# Acknowledgements + +This work was supported in part by National Key R&D Program of China (No. 2022ZD0160900), National Natural Science Foundation of China (Grant No. 61672273, 61832008, 62076119), and was also supported by the Fundamental Research Funds for the Central Universities XJ2023000701 and XJ2023004101. + +# References + +[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In ICCV, pages 6816-6826, 2021. 2 +[2] Iz Beltagy, Matthew E. Peters, and Arman Cohan. Longformer: The long-document transformer. CoRR, abs/2004.05150, 2020. 2 +[3] Gedas Bertasius, Heng Wang, and Lorenzo Torresani. Is space-time attention all you need for video understanding? In ICML, volume 139, pages 813-824, 2021. 2 +[4] Shuqiang Cao, Weixin Luo, Bairui Wang, Wei Zhang, and Lin Ma. A circular window-based cascade transformer for online action detection. CoRR, abs/2208.14209, 2022. 2 +[5] Guo Chen, Sen Xing, Zhe Chen, Yi Wang, Kunchang Li, Yizhuo Li, Yi Liu, Jiahao Wang, Yin-Dong Zheng, Bingkun Huang, Zhiyu Zhao, Junting Pan, Yifei Huang, Zun Wang, Jiashuo Yu, Yinan He, Hongjie Zhang, Tong Lu, Yali Wang, Limin Wang, and Yu Qiao. Internvideo-ego4d: A pack of champion solutions to ego4d challenges. CoRR, abs/2211.09529, 2022. 7, 8 +[6] Guo Chen, Yin-Dong Zheng, Jiahao Wang, Jilan Xu, Yifei Huang, Junting Pan, Yi Wang, Yali Wang, Yu Qiao, Tong Lu, and Limin Wang. Videollm: Modeling video sequence with large language models. CoRR, abs/2305.13292, 2023. 2 +[7] Junwen Chen, Gaurav Mittal, Ye Yu, Yu Kong, and Mei Chen. Gatehub: Gated history unit with background suppression for online action detection. In CVPR, pages 19925-19934, 2022. 1, 2, 7, 8 +[8] MMAction2 Contributors. Openmmlab's next generation video understanding toolbox and benchmark. https://github.com/open-mmlab/mmaction2, 2020.5 +[9] Dima Damen, Hazel Doughty, Giovanni Maria Farinella, Antonino Furnari, Jian Ma, Evangelos Kazakos, Davide Moltisanti, Jonathan Munro, Toby Perrett, Will Price, and Michael Wray. Rescaling egocentric vision: Collection, pipeline and challenges for epic-kitchens-100. International Journal of Computer Vision (IJCV), 130:33-55, 2022. 2, 3, 5, 7, 8 +[10] Roeland De Geest, Efstratios Gavves, Amir Ghodrati, Zhenyang Li, Cees Snoek, and Tinne Tuytelaars. Online action detection. In ECCV, pages 269-284, 2016. 1, 2, 5, 8 +[11] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In 9th International Conference on Learning Representations, ICLR 2021, Virtual Event, Austria, May 3-7, 2021. OpenReview.net, 2021. 2, 8 +[12] Hyunjun Eun, Jinyoung Moon, Jongyoul Park, Chanho Jung, and Changick Kim. Learning to discriminate information for online action detection. In CVPR, pages 806-815, 2020. 2, 8 +[13] Haoqi Fan, Bo Xiong, Karttikeya Mangalam, Yanghao Li, Zhicheng Yan, Jitendra Malik, and Christoph Feichtenhofer. + +Multiscale vision transformers. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 6804-6815. IEEE, 2021. 2 +[14] Antonino Furnari and Giovanni Maria Farinella. What would you expect? anticipating egocentric actions with rolling-unrolling lstms and modality attention. In International Conference on Computer Vision (ICCV), 2019. 1, 2, 5, 7, 8 +[15] Jiyang Gao, Zhenheng Yang, and Ram Nevatia. RED: reinforced encoder-decoder networks for action anticipation. In BMVC, 2017. 2, 7, 8 +[16] Mingfei Gao, Yingbo Zhou, Ran Xu, Richard Socher, and Caiming Xiong. WOAD: weakly supervised online action detection in untrimmed videos. In CVPR, pages 1915-1923, 2021. 2, 8 +[17] Rohit Girdhar and Kristen Grauman. Anticipative Video Transformer. In ICCV, 2021. 1, 2, 5, 7, 8 +[18] Rohit Girdhar, Mannat Singh, Nikhila Ravi, Laurens van der Maaten, Armand Joulin, and Ishan Misra. Omnivore: A single model for many visual modalities. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New Orleans, LA, USA, June 18-24, 2022, pages 16081-16091. IEEE, 2022. 2 +[19] Kristen Grauman, Andrew Westbury, Eugene Byrne, Zachary Chavis, Antonino Furnari, Rohit Girdhar, Jackson Hamburger, Hao Jiang, Miao Liu, Xingyu Liu, Miguel Martin, Tushar Nagarajan, Ilija Radosavovic, Santhosh Kumar Ramakrishnan, Fiona Ryan, Jayant Sharma, Michael Wray, Mengmeng Xu, Eric Zhongcong Xu, Chen Zhao, Siddhant Bansal, Dhruv Batra, Vincent Cartillier, Sean Crane, Tien Do, Morrie Doulaty, Akshay Erapalli, Christoph Feichtenhofer, Adriano Fragomeni, Qichen Fu, Abrham Gebreselasie, Cristina Gonzalez, James Hillis, Xuhua Huang, Yifei Huang, Wenqi Jia, Wesley Khoo, Jachym Kolár, Satwik Kottur, Anurag Kumar, Federico Landini, Chao Li, Yanghao Li, Zhenqiang Li, Karttikeya Mangalam, Raghava Modhugu, Jonathan Munro, Tullie Murrell, Takumi Nishiyasu, Will Price, Paola Ruiz Puentes, Merey Ramazanova, Leda Sari, Kiran Somasundaram, Audrey Southerland, Yusuke Sugano, Ruijie Tao, Minh Vo, Yuchen Wang, Xindi Wu, Takuma Yagi, Ziwei Zhao, Yunyi Zhu, Pablo Arbeláez, David Crandall, Dima Damen, Giovanni Maria Farinella, Christian Fuegen, Bernard Ghanem, Vamsi Krishna Ithapu, C. V. Jawahar, Hanbyul Joo, Kris Kitani, Haizhou Li, Richard A. Newcombe, Aude Oliva, Hyun Soo Park, James M. Rehg, Yoichi Sato, Jianbo Shi, Mike Zheng Shou, Antonio Torralba, Lorenzo Torresani, Mingfei Yan, and Jitendra Malik. Ego4d: Around the world in 3,000 hours of egocentric video. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New Orleans, LA, USA June 18-24, 2022 pages 18973-18990. IEEE, 2022. 8 +[20] Demis Hassabis, Dharshan Kumaran, Christopher Summerfield, and Matthew Botvinick. Neuroscience-inspired artificial intelligence. Neuron, 95(2):245-258, 2017. 2 +[21] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dólar, and Ross B. Girshick. Masked autoencoders are scalable vision learners. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New + +Orleans, LA, USA, June 18-24, 2022, pages 15979-15988. IEEE, 2022. 6 +[22] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778, 2016. 3 +[23] Fabian Caba Heilbron, Victor Escorcia, Bernard Ghanem, and Juan Carlos Niebles. Activitynet: A large-scale video benchmark for human activity understanding. In CVPR, pages 961-970, 2015. 5 +[24] Geoffrey E. Hinton, Nitish Srivastava, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. Improving neural networks by preventing co-adaptation of feature detectors. CoRR, abs/1207.0580, 2012. 5 +[25] Yifei Huang, Minjie Cai, Zhenqiang Li, Feng Lu, and Yoichi Sato. Mutual context network for jointly estimating egocentric gaze and action. IEEE Transactions on Image Processing, 29:7795-7806, 2020. 2 +[26] Yifei Huang, Minjie Cai, Zhenqiang Li, and Yoichi Sato. Predicting gaze in egocentric video by learning task-dependent attention transition. In Proceedings of the European conference on computer vision (ECCV), pages 754-769, 2018. 1 +[27] Yifei Huang, Yusuke Sugano, and Yoichi Sato. Improving action segmentation via graph-based temporal reasoning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 14024-14034, 2020. 1 +[28] Yifei Huang, Lijin Yang, and Yoichi Sato. Compound prototype matching for few-shot action recognition. In European Conference on Computer Vision, pages 351-368, 2022. 2 +[29] Baoxiong Jia, Ting Lei, Song-Chun Zhu, and Siyuan Huang. Egotaskqa: Understanding human tasks in egocentric videos. CoRR, abs/2210.03929, 2022. 8 +[30] Y.-G. Jiang, J. Liu, A. Roshan Zamir, G. Toderici, I. Laptev, M. Shah, and R. Sukthankar. THUMOS challenge: Action recognition with a large number of classes. http://crcv.ucf.edu/THUMOS14/, 2014. 2, 5, 8 +[31] Will Kay, João Carreira, Karen Simonyan, Brian Zhang, Chloe Hillier, Sudheendra Vijayanarasimhan, Fabio Viola, Tim Green, Trevor Back, Paul Natsev, Mustafa Suleyman, and Andrew Zisserman. The kinetics human action video dataset. CoRR, abs/1705.06950, 2017. 5, 8 +[32] Kris M Kitani, Brian D Ziebart, James Andrew Bagnell, and Martial Hebert. Activity forecasting. In Computer Vision-ECCV 2012: 12th European Conference on Computer Vision, Florence, Italy, October 7-13, 2012, Proceedings, Part IV 12, pages 201-214. Springer, 2012. 1 +[33] Hema S Koppula and Ashutosh Saxena. Anticipating human activities using object affordances for reactive robotic response. IEEE transactions on pattern analysis and machine intelligence, 38(1):14-29, 2015. 1 +[34] Sumin Lee, Hyunjun Eun, Jinyoung Moon, Seokeon Choi, Yoonhyung Kim, Chanho Jung, and Changick Kim. Learning to discriminate information for online action detection: Analysis and application. TPAMI, pages 1-17, 2022. 5, 8 +[35] Kunchang Li, Yali Wang, Yinan He, Yizhuo Li, Yi Wang, Limin Wang, and Yu Qiao. Uniformerv2: Spatiotemporal learning by arming image vits with video uniformer. arXiv preprint arXiv:2211.09552, 2022. 2 + +[36] Kunchang Li, Yali Wang, Yizhuo Li, Yi Wang, Yinan He, Limin Wang, and Yu Qiao. Unmasked teacher: Towards training-efficient video foundation models. arXiv preprint arXiv:2303.16058, 2023. 2 +[37] Zhiqi Li, Zhiding Yu, Wenhai Wang, Anima Anandkumar, Tong Lu, and Jose M Alvarez. Fb-bev: Bev representation from forward-backward view transformations. arXiv preprint arXiv:2308.02236, 2023. 2 +[38] Kevin Qinghong Lin, Alex Jinpeng Wang, Mattia Soldan, Michael Wray, Rui Yan, Eric Zhongcong Xu, Difei Gao, Rong-Cheng Tu, Wenzhe Zhao, Weijie Kong, Chengfei Cai, Hongfa Wang, Dima Damen, Bernard Ghanem, Wei Liu, and Mike Zheng Shou. Egocentric video-language pretraining. CoRR, abs/2206.01670, 2022. 8 +[39] Xiaolong Liu, Qimeng Wang, Yao Hu, Xu Tang, Song Bai, and Xiang Bai. End-to-end temporal action detection with transformer. CoRR, abs/2106.10271, 2021. 2 +[40] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 9992-10002. IEEE, 2021. 2 +[41] Giovanni Pezzulo, Francesco Rigoli, and Karl Friston. Active inference, homeostatic regulation and adaptive behavioural control. Progress in neurobiology, 134:17-35, 2015. 2 +[42] Vasili Ramanishka, Yi-Ting Chen, Teruhisa Mitsu, and Kate Saenko. Toward driving scene understanding: A dataset for learning driver behavior and causal reasoning. In CVPR, 2018. 2, 5, 8 +[43] Daniel L Schacter and Donna Rose Addis. The ghosts of past and future. Nature, 445(7123):27-27, 2007. 2 +[44] Fadime Sener, Dipika Singhania, and Angela Yao. Temporal aggregate representations for long-range video understanding. In Andrea Vedaldi, Horst Bischof, Thomas Brox, and Jan-Michael Frahm, editors, Computer Vision - ECCV 2020 - 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XVI, volume 12361 of Lecture Notes in Computer Science, pages 154-171. Springer, 2020. 1, 7 +[45] Zheng Shou, Jonathan Chan, Alireza Zareian, Kazuyuki Miyazawa, and Shih-Fu Chang. CDC: convolutional-deconvolutional networks for precise temporal action localization in untrimmed videos. In 2017 IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2017, Honolulu, HI, USA, July 21-26, 2017, pages 1417-1426. IEEE Computer Society, 2017. 8 +[46] Bilge Soran, Ali Farhadi, and Linda Shapiro. Generating notifications for missing actions: Don't forget to turn the lights off! In Proceedings of the IEEE International Conference on Computer Vision, pages 4669-4677, 2015. 1 +[47] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. Videomae: Masked autoencoders are data-efficient learners for self-supervised video pre-training. CoRR, abs/2203.12602, 2022. 8 +[48] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Hervé Jégou. Training + +data-efficient image transformers & distillation through attention. In Marina Meila and Tong Zhang, editors, Proceedings of the 38th International Conference on Machine Learning, ICML 2021, 18-24 July 2021, Virtual Event, volume 139 of Proceedings of Machine Learning Research, pages 10347-10357. PMLR, 2021. 2 +[49] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. 2 +[50] Limin Wang, Yuanjun Xiong, Zhe Wang, Yu Qiao, Dahua Lin, Xiaou Tang, and Luc Van Gool. Temporal segment networks: Towards good practices for deep action recognition. In ECCV, pages 20-36, 2016. 5 +[51] Pichao Wang, Xue Wang, Fan Wang, Ming Lin, Shuning Chang, Hao Li, and Rong Jin. KVT: k-nn attention for boosting vision transformers. In Shai Avidan, Gabriel J. Brostow, Moustapha Cisse, Giovanni Maria Farinella, and Tal Hassner, editors, Computer Vision - ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXIV, volume 13684 of Lecture Notes in Computer Science, pages 285-302. Springer, 2022. 6 +[52] Sinong Wang, Belinda Z. Li, Madian Khabsa, Han Fang, and Hao Ma. Linformer: Self-attention with linear complexity. CoRR, abs/2006.04768, 2020. 2 +[53] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 548-558. IEEE, 2021. 2 +[54] Xiang Wang, Shiwei Zhang, Zhiwu Qing, Yuanjie Shao, Zhengrong Zuo, Changxin Gao, and Nong Sang. Long short-term transformer for online action detection. In ICCV, 2021. 2, 5, 7, 8 +[55] Yi Wang, Kunchang Li, Yizhuo Li, Yinan He, Bingkun Huang, Zhiyu Zhao, Hongjie Zhang, Jilan Xu, Yi Liu, Zun Wang, et al. Internvideo: General video foundation models via generative and discriminative learning. arXiv preprint arXiv:2212.03191, 2022. 2 +[56] Chao-Yuan Wu, Yanghao Li, Karttikeya Mangalam, Haoqi Fan, Bo Xiong, Jitendra Malik, and Christoph Feichtenhofer. Memvit: Memory-augmented multiscale vision transformer for efficient long-term video recognition. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New Orleans, LA, USA, June 18-24, 2022, pages 13577-13587. IEEE, 2022. 2 +[57] Mingze Xu, Mingfei Gao, Yi-Ting Chen, Larry S Davis, and David J Crandall. Temporal recurrent networks for online action detection. In ICCV, pages 5532-5541, 2019. 2, 5, 7, 8 +[58] Mingze Xu, Yuanjun Xiong, Hao Chen, Xinyu Li, Wei Xia, Zhuowen Tu, and Stefano Soatto. Long short-term transformer for online action detection. In NeurIPS, 2021. 1, 2, 3, 5, 6, 7, 8 +[59] Xinyu Xu, Yong-Lu Li, and Cewu Lu. Learning to anticipate future with dynamic context removal. In Proceedings of + +the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12734-12744, 2022. 7 +[60] Antoine Yang, Antoine Miech, Josef Sivic, Ivan Laptev, and Cordelia Schmid. Tubedetr: Spatio-temporal video grounding with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 16442-16453, June 2022. 2 +[61] Le Yang, Junwei Han, and Dingwen Zhang. Colar: Effective and efficient online action detection by consulting exemplars. In CVPR, 2022. 2, 5, 8 +[62] Cunjun Yu, Xiao Ma, Jiawei Ren, Haiyu Zhao, and Shuai Yi. Spatio-temporal graph transformer networks for pedestrian trajectory prediction. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XII 16, pages 507-523. Springer, 2020. 1 +[63] Chen-Lin Zhang, Jianxin Wu, and Yin Li. Actionformer: Localizing moments of actions with transformers. CoRR, abs/2202.07925, 2022. 2 +[64] Hongyi Zhang, Moustapha Cisse, Yann N. Dauphin, and David Lopez-Paz. mixup: Beyond empirical risk minimization. In 6th International Conference on Learning Representations, ICLR 2018, Vancouver, BC, Canada, April 30 - May 3, 2018, Conference Track Proceedings. OpenReview.net, 2018. 6 +[65] Yanyi Zhang, Xinyu Li, Chunhui Liu, Bing Shuai, Yi Zhu, Biagio Brattoli, Hao Chen, Ivan Marsic, and Joseph Tighe. Vidtr: Video transformer without convolutions. In ICCV, pages 13557-13567, 2021. 2 +[66] Peisen Zhao, Jiajie Wang, Lingxi Xie, Ya Zhang, Yanfeng Wang, and Qi Tian. Privileged knowledge distillation for online action detection. CoRR, abs/2011.09158, 2020. 8 +[67] Yue Zhao and Philipp Krahenbuhl. Real-time online video detection with temporal smoothing transformers. In European Conference on Computer Vision (ECCV), 2022. 1, 2, 3, 5, 6, 7, 8 +[68] Yue Zhao, Ishan Misra, Philipp Krahenbuhl, and Rohit Girdhar. Learning video representations from large language models. CoRR, abs/2212.04501, 2022. 8 \ No newline at end of file diff --git a/2023/Memory-and-Anticipation Transformer for Online Action Understanding/images.zip b/2023/Memory-and-Anticipation Transformer for Online Action Understanding/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..7800f5f659fe59d2e390d18af4fb7016842e0eba --- /dev/null +++ b/2023/Memory-and-Anticipation Transformer for Online Action Understanding/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:d8254ef3c8588f40b089dd177c954fdd62738fd20e838e0cf54adf589ebe9999 +size 601508 diff --git a/2023/Memory-and-Anticipation Transformer for Online Action Understanding/layout.json b/2023/Memory-and-Anticipation Transformer for Online Action Understanding/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..8b8ffaa2b05390625c3a63da787a88c3aa4762c7 --- /dev/null +++ b/2023/Memory-and-Anticipation Transformer for Online Action Understanding/layout.json @@ -0,0 +1,10675 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 70, + 103, + 523, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 103, + 523, + 121 + ], + "spans": [ + { + "bbox": [ + 70, + 103, + 523, + 121 + ], + "type": "text", + "content": "Memory-and-Anticipation Transformer for Online Action Understanding" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "spans": [ + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "text", + "content": "Jiahao Wang" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "text", + "content": " Guo Chen" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "inline_equation", + "content": "^{1,2*}" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "text", + "content": " Yifei Huang" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "text", + "content": " Limin Wang" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "inline_equation", + "content": "^{1,2}" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "text", + "content": " Tong Lu" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "inline_equation", + "content": "^{1\\boxtimes}" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "text", + "content": " State Key Laboratory for Novel Software Technology, Nanjing University \n" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 104, + 142, + 489, + 186 + ], + "type": "text", + "content": " Shanghai AI Laboratory" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 158, + 213, + 206, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 158, + 213, + 206, + 225 + ], + "spans": [ + { + "bbox": [ + 158, + 213, + 206, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 238, + 290, + 501 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 238, + 290, + 501 + ], + "spans": [ + { + "bbox": [ + 47, + 238, + 290, + 501 + ], + "type": "text", + "content": "Most existing forecasting systems are memory-based methods, which attempt to mimic human forecasting ability by employing various memory mechanisms and have progressed in temporal modeling for memory dependency. Nevertheless, an obvious weakness of this paradigm is that it can only model limited historical dependence and can not transcend the past. In this paper, we rethink the temporal dependence of event evolution and propose a novel memory-anticipation-based paradigm to model an entire temporal structure, including the past, present, and future. Based on this idea, we present Memory-and-Anticipation Transformer (MAT), a memory-anticipation-based approach, to address the online action detection and anticipation tasks. In addition, owing to the inherent superiority of MAT, it can process online action detection and anticipation tasks in a unified manner. The proposed MAT model is tested on four challenging benchmarks TVSeries, THUMOS'14, HDD, and EPIC-Kitchens-100, for online action detection and anticipation tasks, and it significantly outperforms all existing methods. Code is available at https://github.com/Echo0125/Memory-and-Anticipation-Transformer." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 526, + 128, + 539 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 526, + 128, + 539 + ], + "spans": [ + { + "bbox": [ + 47, + 526, + 128, + 539 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 548, + 287, + 632 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 548, + 287, + 632 + ], + "spans": [ + { + "bbox": [ + 46, + 548, + 287, + 632 + ], + "type": "text", + "content": "Online anticipation [32] or detection [10] in computer vision attempt to perceive future or present states from a historical perspective. They are the crucial factors of AI systems that engage with complex real environments and interact with other agents, e.g. wearable devices [46], human-robot interaction systems [33], and autonomous vehicles [62]." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 632, + 288, + 693 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 632, + 288, + 693 + ], + "spans": [ + { + "bbox": [ + 46, + 632, + 288, + 693 + ], + "type": "text", + "content": "Human beings frequently imagine future events based on past experiences. Similarly, anticipating future events inherently requires modeling past actions or the progression of events to predict what will happen next. To bridge the gap with human forecasting ability, current systems" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 308, + 212, + 545, + 395 + ], + "blocks": [ + { + "bbox": [ + 308, + 212, + 545, + 395 + ], + "lines": [ + { + "bbox": [ + 308, + 212, + 545, + 395 + ], + "spans": [ + { + "bbox": [ + 308, + 212, + 545, + 395 + ], + "type": "image", + "image_path": "fda5038fd67c3a9bd266960e1d244aff40dc654540c84fad370ae12ca4e16ffa.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 403, + 547, + 492 + ], + "lines": [ + { + "bbox": [ + 305, + 403, + 547, + 492 + ], + "spans": [ + { + "bbox": [ + 305, + 403, + 547, + 492 + ], + "type": "text", + "content": "Figure 1: Examples for the forward influence of memory and backward constraint of anticipation. (a) An athlete prepares to start, starts to run, and then jumps to form the result of completing a high jump; (b) The goals of a camera wearer for cutting a tomato dictate the sequence of actions he will perform: hold the knife, get ready to cut, etc.; (c) Compared with the memory-based method, the memory-anticipation-based method is able to establish circular dependencies between memory and future." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 508, + 545, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 508, + 545, + 616 + ], + "spans": [ + { + "bbox": [ + 304, + 508, + 545, + 616 + ], + "type": "text", + "content": "strive to mimic this cognitive ability by employing different memory mechanisms [58, 26, 7, 67, 44, 17]. Previous research [14, 44] demonstrated that modeling long temporal context is crucial for accurate anticipation. LSTR [58] further decomposes the memory encoder into long and short-term stages for online action detection and anticipation, allowing for the extraction of more representative memory features. Similarly, research efforts such as [67, 7, 27] have also illustrated improvements based on this principle." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 546, + 714 + ], + "type": "text", + "content": "However, despite various memory-based approaches, memory is not the only driver of present or future action. The synchronization between shot transitions and the evolution of actor behavior appears to cohere with the beliefs and wills of the event weavers, be they actors or camerewearers. In (a) and (b) of Fig 1, we use the examples of high jumping and cooking to show the forward influence of memory and backward constraint of anticipation." + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 61, + 702, + 282, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 702, + 282, + 713 + ], + "spans": [ + { + "bbox": [ + 61, + 702, + 282, + 713 + ], + "type": "text", + "content": "* Equal contribution, ⌒ Corresponding author (lutong@nju.edu.cn)" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "13824" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 288, + 167 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 288, + 167 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 288, + 167 + ], + "type": "text", + "content": "Upon closer examination of both examples, it has been observed that future-oriented thoughts may impact action and memory, which seems modulated by the encoding of new information [43, 25]. Additionally, anticipation may change as ongoing behavior progresses and memory is updated [41, 20]. This indicates that there exists a circular interdependence between anticipation and memory, constraining the evolution of behavior or events." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 170, + 287, + 350 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 170, + 287, + 350 + ], + "spans": [ + { + "bbox": [ + 46, + 170, + 287, + 350 + ], + "type": "text", + "content": "Based on the preceding analysis, we reevaluate the temporal dependencies inherent in memory-based methods. In their preoccupation with the impact of memory on anticipation, these memory-based methods tend to overlook the inverse direction of impact, i.e., anticipation on memory. Consequently, historical representations are not adequately corrected, thereby risking impeding any attempts to transcend the past. Against this backdrop, we assert that a comprehensive temporal structure seamlessly integrates memory and anticipation is indispensable. In other words, a memory-anticipation-based method building circular dependencies between memory and anticipation, as shown in Fig 1(c), holds tremendous promise for enhancing cognitive inference capabilities and advanced understanding of AI systems about the present and future." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 351, + 287, + 542 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 351, + 287, + 542 + ], + "spans": [ + { + "bbox": [ + 46, + 351, + 287, + 542 + ], + "type": "text", + "content": "To this end, we propose Memory-and-Anticipation Transformer (MAT), a novel memory-anticipation-based approach that fully models the complete temporal context, including history, present, and future. A Progressive Memory Encoder is designed to provide a more precise history summary by compressing long- and short-term memory in a segment-based fashion. Meanwhile, we propose our key idea of modeling circular dependencies between memory and future, implemented as Memory-Anticipation Circular Decoder. It first learns latent future features in a supervised manner, then updates iteratively the enhanced short-term memory and the latent future features by performing Conditional circular Interaction between them. Among them, multiple interaction processes capture the circular dependency and supervise the output to maintain stable features with real semantics." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 544, + 287, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 544, + 287, + 640 + ], + "spans": [ + { + "bbox": [ + 46, + 544, + 287, + 640 + ], + "type": "text", + "content": "Remarkably, owing to the inherent superiority of our model design, we are able to adapt both tasks, i.e., online action detection and anticipation, in a unified manner, spanning the training and online inference stages. For any given dataset, the MAT model obviates the need for separate training or testing for each task. Rather, a single training process is enough, and during inference, the corresponding token for each task can be extracted effortlessly." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 642, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 288, + 715 + ], + "type": "text", + "content": "In summary, our contributions are 1). We rethink the temporal dependence of event evolution and propose a memory-anticipation-based paradigm for the circular interaction of memory and anticipation, introducing the concept of memory and future circular dependence. 2). We propose a unified architecture Memory-Anticipation Transformer" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 72, + 545, + 145 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 145 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 145 + ], + "type": "text", + "content": "(MAT) that simultaneously processes online action detection and anticipation, showing effective performance. 3). MAT significantly outperforms all existing methods on four challenging benchmarks for online action detection and anticipation tasks, i.e., TVSeries [10], THUMOS'14 [30], HDD [42] and EPIC-Kitchens-100 [9]." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 306, + 155, + 392, + 167 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 155, + 392, + 167 + ], + "spans": [ + { + "bbox": [ + 306, + 155, + 392, + 167 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 175, + 545, + 366 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 175, + 545, + 366 + ], + "spans": [ + { + "bbox": [ + 304, + 175, + 545, + 366 + ], + "type": "text", + "content": "Online Action Detection and Anticipation. Online action detection [10] aims to predict the action as it happens without accessing the future. Previous methods [57, 12, 16, 61, 54, 58, 7, 67, 4] for online action detection include recurrent networks, reinforcement learning, and, more recently, transformers. [15] uses a reinforced network to encourage making great decisions as early as possible. [57] adopts RNN to generate future predictions to improve online action detection. [58] proposes a transformer to scale the history spanning a longer duration. The target of action anticipation [9, 14, 17, 56] is predicting what actions will occur after a certain time. RULSTM [14] explores action anticipation and proposes an LSTM-based network to solve this problem. AVT [17] proposed an end-to-end attention-based model for anticipative video modeling and learns feature representations by self-supervised methods." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 367, + 545, + 486 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 367, + 545, + 486 + ], + "spans": [ + { + "bbox": [ + 304, + 367, + 545, + 486 + ], + "type": "text", + "content": "Online action detection and anticipation share two key characteristics: the inability to perceive future representations, with information derived solely from historical context, and the goal of predicting actions after a certain time. Previous research has typically studied the model for each task in isolation [61, 7] or trained and tested them separately [58, 67], ignoring the potential benefits of leveraging their shared characteristics. We propose a novel unified framework, named MAT, to address this limitation, which allows us to train or infer both tasks simultaneously." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 487, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 487, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 487, + 545, + 713 + ], + "type": "text", + "content": "Transformer for Video Understanding. Transformers have proven successful in natural language processing [49], and researchers have shown increasing interest in its application to vision tasks [11, 48, 40, 53, 18, 37]. Several methods have been proposed to use transformers for temporal modeling in video-related tasks [1, 2, 6, 28, 35, 36, 39, 52, 55, 65]. Timesformer [3] proposes divided attention to capture spatial and temporal information for action recognition separately. MViT [13] builds a feature hierarchy by progressively expanding channel capacity and reducing video spatial-temporal resolution. Actionformer [63] adopts the transformer architecture with local attention for temporal action localization. TubeDETR [60] tackles video grounding with an encoder-decoder transformer-based architecture to efficiently encode spatial and multi-modal interactions. Our MAT model is also built upon the transformer, utilizing its encoder and decoder architectures. We meticulously integrate the transformer blocks to implement our memory encoder and memory-anticipation circular decoder." + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13825" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 82, + 547, + 198 + ], + "blocks": [ + { + "bbox": [ + 89, + 70, + 209, + 81 + ], + "lines": [ + { + "bbox": [ + 89, + 70, + 209, + 81 + ], + "spans": [ + { + "bbox": [ + 89, + 70, + 209, + 81 + ], + "type": "text", + "content": "Progressive Memory Encoder" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 277, + 70, + 434, + 81 + ], + "lines": [ + { + "bbox": [ + 277, + 70, + 434, + 81 + ], + "spans": [ + { + "bbox": [ + 277, + 70, + 434, + 81 + ], + "type": "text", + "content": "Memory-Anticipation Circular Decoder" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 50, + 82, + 547, + 198 + ], + "lines": [ + { + "bbox": [ + 50, + 82, + 547, + 198 + ], + "spans": [ + { + "bbox": [ + 50, + 82, + 547, + 198 + ], + "type": "image", + "image_path": "84096c7762465264f596457b38a592b26977a4f3d7eeb453f581268434854c36.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 201, + 547, + 257 + ], + "lines": [ + { + "bbox": [ + 46, + 201, + 547, + 257 + ], + "spans": [ + { + "bbox": [ + 46, + 201, + 547, + 257 + ], + "type": "text", + "content": "Figure 2: MAT architecture. We first divide the temporal sequence into long-term and short-term memories. In Progressive Memory Encoder, long-term memory queries " + }, + { + "bbox": [ + 46, + 201, + 547, + 257 + ], + "type": "inline_equation", + "content": "\\mathbf{Q}_L" + }, + { + "bbox": [ + 46, + 201, + 547, + 257 + ], + "type": "text", + "content": " progressively map the long-term to an abstract representation and be fed to the transformer decoder block to enhance the short-term memory. Then the Memory-Anticipation Circular Decoder utilizes learnable queries " + }, + { + "bbox": [ + 46, + 201, + 547, + 257 + ], + "type": "inline_equation", + "content": "\\mathbf{Q}_F" + }, + { + "bbox": [ + 46, + 201, + 547, + 257 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 201, + 547, + 257 + ], + "type": "inline_equation", + "content": "\\mathbf{Q}_F'" + }, + { + "bbox": [ + 46, + 201, + 547, + 257 + ], + "type": "text", + "content": " to perceive the future context and circularly updates the historical and future representation. Finally, a weight-shared classifier is adopted to output the classification scores of short-term and future for online action detection and anticipation." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 276, + 139, + 290 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 276, + 139, + 290 + ], + "spans": [ + { + "bbox": [ + 47, + 276, + 139, + 290 + ], + "type": "text", + "content": "3. Problem Setup" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "spans": [ + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "text", + "content": "Online action anticipation and detection share a similar goal of predicting actions in untrimmed video sequences. In the former, we aim to forecast actions after a time gap " + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "text", + "content": ", as defined in [9], while in the latter, we predict the action under " + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "inline_equation", + "content": "\\tau = 0" + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "text", + "content": ". Both tasks require classifying actions without access to future information during inference. We represent the input video as " + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "inline_equation", + "content": "\\mathbf{V} = \\{v_t\\}_{t = -T + 1}^0" + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "text", + "content": ", and our objective is to predict the action category " + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "inline_equation", + "content": "\\tilde{y}_{\\tau} \\in \\{0,1,2,\\dots,C\\}" + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "text", + "content": " occurs after a specified time gap " + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "text", + "content": " in the future. Here, " + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 46, + 297, + 289, + 429 + ], + "type": "text", + "content": " represents the total number of action categories, and label 0 denotes the background category." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 439, + 266, + 453 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 439, + 266, + 453 + ], + "spans": [ + { + "bbox": [ + 47, + 439, + 266, + 453 + ], + "type": "text", + "content": "4. Memory-and-Anticipation Transformer" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 460, + 287, + 627 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 460, + 287, + 627 + ], + "spans": [ + { + "bbox": [ + 46, + 460, + 287, + 627 + ], + "type": "text", + "content": "We now describe Memory-and-Anticipation Transformer (MAT) model architecture, as illustrated in Fig 2. It processes the memory cached in runtime to predict current or future actions. We adopt the encoder-decoder architecture to implement the model. The Progressive Memory Encoder is proposed to improve the quality of compressing long-term memory and enhancing short-term memory, which has a fundamental impact on anticipation and detection. MAT also employs our presented key component Memory-Anticipation Circular Decoder that generates the latent anticipation feature and conducts interaction between memory and anticipation in an iterative loop. We now introduce each model component in detail, followed by the training, online inference, and implementation details." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 635, + 209, + 647 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 635, + 209, + 647 + ], + "spans": [ + { + "bbox": [ + 47, + 635, + 209, + 647 + ], + "type": "text", + "content": "4.1. Progressive Memory Encoder" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 652, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 652, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 652, + 288, + 715 + ], + "type": "text", + "content": "We use video feature " + }, + { + "bbox": [ + 46, + 652, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{F} = \\{f_t\\}_{t = -T + 1}^0\\in \\mathbb{R}^{T\\times D}" + }, + { + "bbox": [ + 46, + 652, + 288, + 715 + ], + "type": "text", + "content": " generated by a pretrained feature extractor as the input to our model, where " + }, + { + "bbox": [ + 46, + 652, + 288, + 715 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 46, + 652, + 288, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 652, + 288, + 715 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 46, + 652, + 288, + 715 + ], + "type": "text", + "content": " are the dimension and length of the feature sequence, respectively. To better handle the long memory, following [58], we divide the feature sequence into" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 277, + 545, + 373 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 277, + 545, + 373 + ], + "spans": [ + { + "bbox": [ + 304, + 277, + 545, + 373 + ], + "type": "text", + "content": "two consecutive memories. The first is the short-term memory that stores only a handful of recently occurred frames. It stores the feature vectors as " + }, + { + "bbox": [ + 304, + 277, + 545, + 373 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_S = \\{f_t\\}_{t = -m_S + 1}^0" + }, + { + "bbox": [ + 304, + 277, + 545, + 373 + ], + "type": "text", + "content": " , where " + }, + { + "bbox": [ + 304, + 277, + 545, + 373 + ], + "type": "inline_equation", + "content": "m_{S}" + }, + { + "bbox": [ + 304, + 277, + 545, + 373 + ], + "type": "text", + "content": " denotes the length. The other, named long-term memory, contains the feature that is far away from the current time, which is defined as " + }, + { + "bbox": [ + 304, + 277, + 545, + 373 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_L = \\{f_t\\}_{t = -T + 1}^{-m_S}" + }, + { + "bbox": [ + 304, + 277, + 545, + 373 + ], + "type": "text", + "content": " . We set " + }, + { + "bbox": [ + 304, + 277, + 545, + 373 + ], + "type": "inline_equation", + "content": "m_{L}" + }, + { + "bbox": [ + 304, + 277, + 545, + 373 + ], + "type": "text", + "content": " to be the length of the long-term memory, which is much longer than the short-term memory." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 375, + 546, + 542 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 375, + 546, + 542 + ], + "spans": [ + { + "bbox": [ + 304, + 375, + 546, + 542 + ], + "type": "text", + "content": "In practice, Progressive Memory Encoder progressively encodes long- and short-term memories. It first compresses the long-term memory to an abstract representation and injects them into the short-term memory. Differing with previous works [58, 67] that separately tackle the long- and short-term memories by one long-term encoder and one short-term decoder, we integrate these two works into a single encoder architecture. It is due to our encoded short-term memory being served for decoders and not as the final output. In our experiments, we observe that the design of the memory encoder is crucial for model performance. Therefore, different with [58, 67], we introduce a novel long-term memory compression method to improve the quality of memory encoding." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "text", + "content": "Segment-based Long-term Memory Compression. LSTR [58] adopts a two-stage compression technique to project the long-term memory to a fixed-length latent embedding. It implements a function similar to the bottleneck layer [22]. Long-term memory, however, represents a long token sequence that often carries much noise. It is problematic to generate attention weights while crossattention queries too many tokens with mixed noise. We propose Segment-based Long-term Memory Compression to alleviate the issue, as shown in Fig 3. Concretely, we first divide " + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_L" + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "text", + "content": " into " + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "inline_equation", + "content": "N_{s}" + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "text", + "content": " non-overlapping memory segments " + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{S} = \\{\\mathbf{s}_i\\}_{i = 1}^{N_s}" + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "text", + "content": " of length " + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\frac{m_L}{N_s}" + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "text", + "content": ". We then employ " + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "inline_equation", + "content": "N_{L}" + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "text", + "content": " learnable tokens " + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{Q}_L\\in \\mathbb{R}^{N_L\\times D}" + }, + { + "bbox": [ + 304, + 544, + 547, + 714 + ], + "type": "text", + "content": " as the long-term memory queries and a weight-shared transformer decoder block to query" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "13826" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": "each segment. " + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "inline_equation", + "content": "\\mathbf{S}" + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": " will be transformed to " + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "inline_equation", + "content": "N_{s}" + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": " segment-level abstract feature " + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "inline_equation", + "content": "\\mathbf{F} = \\{\\mathbf{f}_i\\}_{i = 1}^{N_s}" + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_i\\in \\mathbb{R}^{N_L\\times D}" + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": ". We average pool each " + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_i" + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": " to one vector " + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "inline_equation", + "content": "\\mathbb{R}^D" + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": " and concatenate them to form the long-term compressed segmented memory " + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_L^s\\in \\mathbb{R}^{N_s\\times D}" + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": ". At last, we feed them into two transformer encoder blocks to obtain the final compressed longterm memory " + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_L\\in \\mathbb{R}^{N_s\\times D}" + }, + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 157, + 288, + 316 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 157, + 288, + 316 + ], + "spans": [ + { + "bbox": [ + 46, + 157, + 288, + 316 + ], + "type": "text", + "content": "Short-term Memory Enhancement. As short-term memory " + }, + { + "bbox": [ + 46, + 157, + 288, + 316 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_S = \\{f_t\\}_{t = -m_S + 1}^0" + }, + { + "bbox": [ + 46, + 157, + 288, + 316 + ], + "type": "text", + "content": " contains crucial trends for accurately predicting the current or upcoming activities, we leverage short-term memory as the query to retrieve relevant context from the compressed long-term memory. As illustrated in Fig 2, we employ a transformer causal decoder block to aggregate compressed long-term memory " + }, + { + "bbox": [ + 46, + 157, + 288, + 316 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_L" + }, + { + "bbox": [ + 46, + 157, + 288, + 316 + ], + "type": "text", + "content": " into short-term memory. The enhanced short-term memory " + }, + { + "bbox": [ + 46, + 157, + 288, + 316 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S" + }, + { + "bbox": [ + 46, + 157, + 288, + 316 + ], + "type": "text", + "content": " is then used to identify actions at each timestep, constituting a sequence of previously occurring actions and predicting future states and actions. We use frame-level action labels to supervise the dense classification task, encouraging the model to produce a clear sequence of historical behavior." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 320, + 257, + 333 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 320, + 257, + 333 + ], + "spans": [ + { + "bbox": [ + 47, + 320, + 257, + 333 + ], + "type": "text", + "content": "4.2. Memory-Anticipation Circular Decoder" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 339, + 287, + 446 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 339, + 287, + 446 + ], + "spans": [ + { + "bbox": [ + 46, + 339, + 287, + 446 + ], + "type": "text", + "content": "To implement our key idea that considers the co-reaction between anticipation and memory, we carefully design Memory-Anticipation Circular Decoder that circularly performs interaction between them. It first generates the latent anticipation that is a prerequisite for memory-anticipation interaction. Then, Conditional Circular Interaction will generate new memories and anticipation conditioned on old ones iteratively. Finally, a weight-shared classification head will supervise the generated memories and anticipation." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": "Latent Anticipation Generation. Initially, we do not have an anticipation state. Therefore, we must first generate a latent anticipation feature, i.e., a future representation containing abstract information derived from known memory. Given the compressed long-term memory " + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_L" + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": " and short-term memory " + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S" + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": ", we first concatenate them to form the entire memory " + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_E = [\\widehat{\\mathbf{M}}_L, \\widehat{\\mathbf{M}}_S]" + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "inline_equation", + "content": "[\\cdot, \\cdot]" + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": " is the concatenating operation along the temporal dimension. Then, we use " + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "inline_equation", + "content": "N_F" + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": " future queries " + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{Q}_F \\in \\mathbb{R}^{N_F \\times D}" + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": " and a transformer decoder block to query " + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{M}_E" + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": ". The updated future queries are represented as the latent anticipation features " + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A \\in \\mathbb{R}^{N_F \\times D}" + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": " at the current state. We use future information, e.g., future video features and future action labels, to supervise " + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A" + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": ". In practice, we use information from the next " + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "inline_equation", + "content": "T_F" + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": " seconds. Since " + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A" + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": " is only used to describe the latent future states, too large future embeddings may overfit the anticipation representation. We set " + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "inline_equation", + "content": "N_F" + }, + { + "bbox": [ + 46, + 447, + 288, + 714 + ], + "type": "text", + "content": " to be smaller than the length of the used future information sequence. Then we use bilinear interpolation to upsample it to align for point-to-point supervision. Note that although we use future information here, this does not lead to an information leak. The model will generate preliminary anticipation" + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 309, + 72, + 545, + 200 + ], + "blocks": [ + { + "bbox": [ + 309, + 72, + 545, + 200 + ], + "lines": [ + { + "bbox": [ + 309, + 72, + 545, + 200 + ], + "spans": [ + { + "bbox": [ + 309, + 72, + 545, + 200 + ], + "type": "image", + "image_path": "cf0bbbf71d6b4c46b1bd735c217ba1258943f1d92de9b2a59da2728a1ae4d20f.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 210, + 545, + 243 + ], + "lines": [ + { + "bbox": [ + 305, + 210, + 545, + 243 + ], + "spans": [ + { + "bbox": [ + 305, + 210, + 545, + 243 + ], + "type": "text", + "content": "Figure 3: Segment-based Long-term Memory Compression. For example, given " + }, + { + "bbox": [ + 305, + 210, + 545, + 243 + ], + "type": "inline_equation", + "content": "m_{L} = 9" + }, + { + "bbox": [ + 305, + 210, + 545, + 243 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 305, + 210, + 545, + 243 + ], + "type": "inline_equation", + "content": "N_{s} = 3" + }, + { + "bbox": [ + 305, + 210, + 545, + 243 + ], + "type": "text", + "content": ", the process is shown above. We can finally obtain compressed features " + }, + { + "bbox": [ + 305, + 210, + 545, + 243 + ], + "type": "inline_equation", + "content": "\\widehat{M}_L" + }, + { + "bbox": [ + 305, + 210, + 545, + 243 + ], + "type": "text", + "content": " of length 3." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 266, + 543, + 277 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 266, + 543, + 277 + ], + "spans": [ + { + "bbox": [ + 305, + 266, + 543, + 277 + ], + "type": "text", + "content": "in the inference phase and not use future labels or features." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 277, + 545, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 277, + 545, + 361 + ], + "spans": [ + { + "bbox": [ + 305, + 277, + 545, + 361 + ], + "type": "text", + "content": "Conditional Circular Interaction. So far, we have generated long-term memory " + }, + { + "bbox": [ + 305, + 277, + 545, + 361 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_L" + }, + { + "bbox": [ + 305, + 277, + 545, + 361 + ], + "type": "text", + "content": ", short-term memory " + }, + { + "bbox": [ + 305, + 277, + 545, + 361 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S" + }, + { + "bbox": [ + 305, + 277, + 545, + 361 + ], + "type": "text", + "content": " and latent anticipation features " + }, + { + "bbox": [ + 305, + 277, + 545, + 361 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A" + }, + { + "bbox": [ + 305, + 277, + 545, + 361 + ], + "type": "text", + "content": ". The memories, however, are limited to the past and can not go beyond history. We now describe how Conditional Circular Interaction works. For brevity, we detail how memory and anticipation interact with each other one time." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "spans": [ + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "text", + "content": "As shown in Fig 4, we first concatenate " + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_L" + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S" + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A" + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "text", + "content": " to form the entire feature " + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_E = [\\widehat{\\mathbf{M}}_L, \\widehat{\\mathbf{M}}_S, \\mathbf{F}_A]" + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "text", + "content": ". Then, " + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_E" + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S" + }, + { + "bbox": [ + 305, + 361, + 545, + 401 + ], + "type": "text", + "content": " are feed into a transformer decoder block:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 356, + 410, + 545, + 425 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 356, + 410, + 545, + 425 + ], + "spans": [ + { + "bbox": [ + 356, + 410, + 545, + 425 + ], + "type": "interline_equation", + "content": "\\widehat {\\mathbf {M}} _ {S} ^ {\\prime} = \\operatorname {C r o s s A t t n} \\left(\\widehat {\\mathbf {M}} _ {S}, \\mathbf {F} _ {E}, \\mathbf {F} _ {E}\\right), \\tag {1}", + "image_path": "fa7247ea5c0c79402d7facdee63ae48be92f8c3ed8af45e93a048b03ce64dd81.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "spans": [ + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "inline_equation", + "content": "\\mathrm{CrossAttn}(Q,K,V)" + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "text", + "content": " is the cross-attention layer in the transformer decoder block. The updated short-term memory is represented as " + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S^{\\prime}" + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "text", + "content": ". Since " + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_E" + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "text", + "content": " contains memories and anticipation, " + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S" + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "text", + "content": " as a query condition dynamically extracts new semantics mixed with memories and anticipation from three representations. Next, we re-concatenate " + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_L" + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S^{\\prime}" + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A" + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "text", + "content": " to generate the new entire feature " + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_E^{\\prime} = [\\widehat{\\mathbf{M}}_L,\\widehat{\\mathbf{M}}_S^{\\prime},\\mathbf{F}_A]" + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "text", + "content": ". Another transformer decoder block is used to query " + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_E^{\\prime}" + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "text", + "content": ", with " + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A" + }, + { + "bbox": [ + 305, + 434, + 545, + 548 + ], + "type": "text", + "content": " as the query condition:" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 359, + 557, + 545, + 571 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 359, + 557, + 545, + 571 + ], + "spans": [ + { + "bbox": [ + 359, + 557, + 545, + 571 + ], + "type": "interline_equation", + "content": "\\mathbf {F} _ {A} ^ {\\prime} = \\operatorname {C r o s s A t t n} \\left(\\mathbf {F} _ {A}, \\mathbf {F} _ {E} ^ {\\prime}, \\mathbf {F} _ {E} ^ {\\prime}\\right), \\tag {2}", + "image_path": "bb5c430fab5813f021d05c059bc548f04c44d7a5cf21d3560bddcf7bd79bcf68.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 580, + 545, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 580, + 545, + 628 + ], + "spans": [ + { + "bbox": [ + 305, + 580, + 545, + 628 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 580, + 545, + 628 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A^\\prime" + }, + { + "bbox": [ + 305, + 580, + 545, + 628 + ], + "type": "text", + "content": " is the resulting anticipation features. After that, " + }, + { + "bbox": [ + 305, + 580, + 545, + 628 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A^\\prime" + }, + { + "bbox": [ + 305, + 580, + 545, + 628 + ], + "type": "text", + "content": " is injected with the higher-order inferred semantics brought about by the interaction between memory and anticipation." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "type": "text", + "content": "In the interaction process, the generated " + }, + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S^{\\prime}" + }, + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "type": "text", + "content": " is both supervised like the above initial anticipation features. It should be noted that different from generating latent initial anticipation through fewer future queries, we find that using a new group of future queries " + }, + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{Q}_F^{\\prime} \\in \\mathbb{R}^{N_F^{\\prime} \\times D}" + }, + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "type": "text", + "content": " strictly aligned future information sequences of " + }, + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "type": "inline_equation", + "content": "T_{F}" + }, + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "type": "text", + "content": " seconds in the first interaction process to replace the " + }, + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A" + }, + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{Q}_F^{\\prime}" + }, + { + "bbox": [ + 304, + 628, + 545, + 714 + ], + "type": "text", + "content": ", bring" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13827" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 48, + 70, + 289, + 175 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 289, + 175 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 289, + 175 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 289, + 175 + ], + "type": "image", + "image_path": "7fe50402cc49b9a7ca248989783fbd5f5eff4f00abb59eea7fef14c4a3887e7f.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 183, + 288, + 217 + ], + "lines": [ + { + "bbox": [ + 46, + 183, + 288, + 217 + ], + "spans": [ + { + "bbox": [ + 46, + 183, + 288, + 217 + ], + "type": "text", + "content": "Figure 4: Conditional circular interaction dynamically updates and re-constructs the context between memories and anticipation by aggregating different temporal information." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "spans": [ + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "text", + "content": "performance improvement. Thus, we point-to-point supervise the anticipation " + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A^\\prime" + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "text", + "content": " generated by each interaction process. Meanwhile, this design is more natural to output the corresponding token according to the anticipation gap time. We circularly perform the interaction process " + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "inline_equation", + "content": "N_{t}" + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "text", + "content": " times until saturation. The yielded " + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S^{\\prime}" + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A^\\prime" + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "text", + "content": " in one interaction process become the new " + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S" + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A" + }, + { + "bbox": [ + 46, + 235, + 287, + 334 + ], + "type": "text", + "content": " and are passed to the next interaction process." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 340, + 111, + 353 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 340, + 111, + 353 + ], + "spans": [ + { + "bbox": [ + 47, + 340, + 111, + 353 + ], + "type": "text", + "content": "4.3. Training" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 358, + 287, + 441 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 358, + 287, + 441 + ], + "spans": [ + { + "bbox": [ + 46, + 358, + 287, + 441 + ], + "type": "text", + "content": "Our MAT model relies on action steps of short-term memory to predict the current or future action. These steps are utilized as auxiliary information to benefit action detection and anticipation. It is worth noting that since the MAT model regards online action detection and anticipation as the same tasks with different settings, we can define the loss function in a unified fashion." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "spans": [ + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "text", + "content": "For the " + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S" + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "text", + "content": " generated by the encoder, we feed it to a classifier to generate the action probabilities " + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{Y}}_S = \\{\\widehat{\\mathbf{y}}_S^i\\}_{i=1}^{m_S}" + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "text", + "content": ". We then supervise the whole short-term memory using a cross-entropy loss with the labeled action, " + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "inline_equation", + "content": "\\{c_S^i\\}_{i=1}^{m_S}" + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "text", + "content": ". Learned future features " + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A" + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "text", + "content": " are fed into the same classifier to generate the probabilities " + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{Y}}_F = \\{\\widehat{\\mathbf{y}}_F^i\\}_{i=1}^{N_F}" + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "text", + "content": " and we also adopt a cross-entropy loss with the target, " + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "inline_equation", + "content": "\\{c_F^i\\}_{i=1}^{m_S}" + }, + { + "bbox": [ + 47, + 442, + 288, + 528 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 61, + 533, + 287, + 566 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 533, + 287, + 566 + ], + "spans": [ + { + "bbox": [ + 61, + 533, + 287, + 566 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {S} ^ {0} = - \\sum_ {i = 1} ^ {m _ {S}} \\log \\widehat {\\mathbf {y}} _ {S} ^ {i} [ c _ {S} ^ {i} ], \\mathcal {L} _ {F} ^ {0} = - \\sum_ {i = 1} ^ {N _ {F}} \\log \\widehat {\\mathbf {y}} _ {F} ^ {i} [ c _ {F} ^ {i} ], \\tag {3}", + "image_path": "1c26afeac11413a96077e8c0db4785c0f70ae37784a1b46b918648d91c76e187.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "spans": [ + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_S^0" + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_F^0" + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "text", + "content": " are the loss function of encoded shortterm memory and initial anticipation features, respectively. As the conditional circular interaction is conducted " + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "inline_equation", + "content": "N_{t}" + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "text", + "content": " times, we use " + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_S^i" + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_F^i" + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "text", + "content": " to represent the loss of memory and anticipation in each interaction process, where " + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "inline_equation", + "content": "1\\leq i\\leq N_{t}" + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "text", + "content": ". Their calculation is similar to " + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_S^0" + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_F^0" + }, + { + "bbox": [ + 46, + 571, + 287, + 656 + ], + "type": "text", + "content": ". The final training loss is formulated by:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 103, + 662, + 287, + 696 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 103, + 662, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 103, + 662, + 287, + 696 + ], + "type": "interline_equation", + "content": "\\mathcal {L} = \\sum_ {i = 0} ^ {N _ {t}} \\lambda_ {s} ^ {i} \\cdot \\mathcal {L} _ {S} ^ {i} + \\lambda_ {f} \\sum_ {i = 0} ^ {N _ {t}} \\mathcal {L} _ {F} ^ {i}, \\tag {4}", + "image_path": "a508db6a180e3ced6332eb26c5c420cb4a3ad3abad858c2fe307bfc76529b6c2.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 701, + 231, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 701, + 231, + 714 + ], + "spans": [ + { + "bbox": [ + 47, + 701, + 231, + 714 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 701, + 231, + 714 + ], + "type": "inline_equation", + "content": "\\lambda_s^i" + }, + { + "bbox": [ + 47, + 701, + 231, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 701, + 231, + 714 + ], + "type": "inline_equation", + "content": "\\lambda_{f}" + }, + { + "bbox": [ + 47, + 701, + 231, + 714 + ], + "type": "text", + "content": " are the balance coefficients." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 72, + 408, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 408, + 83 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 408, + 83 + ], + "type": "text", + "content": "4.4. Online Inference" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "spans": [ + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "type": "text", + "content": "The existing works [57, 61, 58, 67, 17] test each task independently. Thanks to the design of the unified framework, MAT simultaneously infers online action detection and anticipation tasks on one streaming video. It uses the output " + }, + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S" + }, + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A" + }, + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "type": "text", + "content": " produced by the last interaction as results of online action detection and anticipation, respectively. We take out the last token of " + }, + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S" + }, + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "type": "text", + "content": " for online action detection. For action anticipation, according to gap time " + }, + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "type": "text", + "content": ", we take out the corresponding token from " + }, + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A" + }, + { + "bbox": [ + 304, + 91, + 547, + 202 + ], + "type": "text", + "content": " for forecasting." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 213, + 388, + 227 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 213, + 388, + 227 + ], + "spans": [ + { + "bbox": [ + 306, + 213, + 388, + 227 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 233, + 423, + 245 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 233, + 423, + 245 + ], + "spans": [ + { + "bbox": [ + 306, + 233, + 423, + 245 + ], + "type": "text", + "content": "5.1. Dataset and Metrics" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 253, + 545, + 384 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 253, + 545, + 384 + ], + "spans": [ + { + "bbox": [ + 304, + 253, + 545, + 384 + ], + "type": "text", + "content": "Dataset. We test on three online action detection datasets. THUMOS'14 [30] consists of over 20 hours of sports video annotated with 20 actions. TVSeries [10] includes 27 episodes of 6 popular TV series, about 150 minutes each and 16 hours total. HDD [42] is a largescale human driving video dataset comprising 104 hours of untrimmed videos and 11 action categories. Furthermore, we evaluate on EpicKitchens-100 [9] that contains 100 hours of egocentric videos with at least 90K action segments and whose narrations are mapped to 97 verb classes and 300 noun classes." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 385, + 545, + 469 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 385, + 545, + 469 + ], + "spans": [ + { + "bbox": [ + 304, + 385, + 545, + 469 + ], + "type": "text", + "content": "Evaluation Metrics. For online action detection, following previous works [10, 34, 54, 58, 61], we use per-frame mean Average Precision (mAP) on THUMOS'14 and HDD, and per-frame mean calibrated Average Precision (mcAP) [10] on TVSeries. For action anticipation, we employ Top-5 Verb/Noun/Action Recall to measure the performance with an anticipation period " + }, + { + "bbox": [ + 304, + 385, + 545, + 469 + ], + "type": "inline_equation", + "content": "\\tau = 1s" + }, + { + "bbox": [ + 304, + 385, + 545, + 469 + ], + "type": "text", + "content": " [9]." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 479, + 437, + 491 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 479, + 437, + 491 + ], + "spans": [ + { + "bbox": [ + 306, + 479, + 437, + 491 + ], + "type": "text", + "content": "5.2. Implementation details" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 498, + 545, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 498, + 545, + 616 + ], + "spans": [ + { + "bbox": [ + 304, + 498, + 545, + 616 + ], + "type": "text", + "content": "Following prior works [57, 58, 67], we conduct our experiments on pre-extracted features. For TVSeries and THUMOS'14, we first resample the videos at 24 FPS and then extract the frames at 4 FPS for training and validation. We adopt a two-stream network [50] to extract feature. We use off-the-shell checkpoint released by mmentation2 [8] that pretrained on ActivityNet v1.3 [23] and Kinetics [31] to extract frame-level RGB and optical features. On EK100, following [14], we resample the videos at 30 FPS and then fine-tune the two-stream TSN on the classification task." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 617, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 545, + 714 + ], + "type": "text", + "content": "Memory Dropping. Despite the promising capabilities of the dense attention mechanism, capturing long-range dependencies remains a challenge. However, relying on the dense attention mechanism may lead to sub-optimization of the network, resulting in a locally optimal solution. We seek to explore memory-dropping strategies for implementing sparse attention during training. We experiment with various approaches, including dropout [24], top-k selec" + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13828" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 53, + 69, + 116, + 141 + ], + "blocks": [ + { + "bbox": [ + 53, + 69, + 116, + 141 + ], + "lines": [ + { + "bbox": [ + 53, + 69, + 116, + 141 + ], + "spans": [ + { + "bbox": [ + 53, + 69, + 116, + 141 + ], + "type": "table", + "html": "
NsmAP
[58]69.6
269.8
470.2
870.4
1270.1
", + "image_path": "2eec5bbb8d04abe7dc692c94d1535d6dc66a71ae20010a19f0667e167326fc95.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 50, + 147, + 116, + 166 + ], + "lines": [ + { + "bbox": [ + 50, + 147, + 116, + 166 + ], + "spans": [ + { + "bbox": [ + 50, + 147, + 116, + 166 + ], + "type": "text", + "content": "(a) Segment number." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 124, + 70, + 197, + 119 + ], + "blocks": [ + { + "bbox": [ + 124, + 70, + 197, + 119 + ], + "lines": [ + { + "bbox": [ + 124, + 70, + 197, + 119 + ], + "spans": [ + { + "bbox": [ + 124, + 70, + 197, + 119 + ], + "type": "table", + "html": "
renewalmAP
070.0
170.4
269.7
", + "image_path": "7f8883c81dba5413d18f759fac6a78bc28b93ff9f5348e6133be46a76ee79937.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "table", + "bbox": [ + 204, + 70, + 310, + 130 + ], + "blocks": [ + { + "bbox": [ + 204, + 70, + 310, + 130 + ], + "lines": [ + { + "bbox": [ + 204, + 70, + 310, + 130 + ], + "spans": [ + { + "bbox": [ + 204, + 70, + 310, + 130 + ], + "type": "table", + "html": "
deepsupervisionmAP
-cls69.9
✓feat69.6
✓cls70.4
✓feat + cls70.2
", + "image_path": "aaf378abb78735e344ea8d7df4f7133ad5aed16ccedc375dbd8e8246dbbb8904.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 120, + 148, + 197, + 167 + ], + "lines": [ + { + "bbox": [ + 120, + 148, + 197, + 167 + ], + "spans": [ + { + "bbox": [ + 120, + 148, + 197, + 167 + ], + "type": "text", + "content": "(b) Future queries renewing." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 318, + 70, + 419, + 121 + ], + "blocks": [ + { + "bbox": [ + 318, + 70, + 419, + 121 + ], + "lines": [ + { + "bbox": [ + 318, + 70, + 419, + 121 + ], + "spans": [ + { + "bbox": [ + 318, + 70, + 419, + 121 + ], + "type": "table", + "html": "
shortfuturemAP
unshared69.6
separately shared70.1
full shared70.4
", + "image_path": "dd312d13e6088ea4305c16d51343d8e61e8c63a2ea15b9fd001bdbfaa2b67dba.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 215, + 148, + 294, + 157 + ], + "lines": [ + { + "bbox": [ + 215, + 148, + 294, + 157 + ], + "spans": [ + { + "bbox": [ + 215, + 148, + 294, + 157 + ], + "type": "text", + "content": "(c) Future supervision." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 425, + 70, + 543, + 141 + ], + "blocks": [ + { + "bbox": [ + 425, + 70, + 543, + 141 + ], + "lines": [ + { + "bbox": [ + 425, + 70, + 543, + 141 + ], + "spans": [ + { + "bbox": [ + 425, + 70, + 543, + 141 + ], + "type": "table", + "html": "
longshortVNA
--32.136.118.1
MC-32.936.918.4
MCMC31.037.418.5
MCMC+35.038.819.5
MC+MC+31.636.818.4
", + "image_path": "a361fde626e4c8bcf28a059a31732d1711bf6283a80b550749b15198b6b75a73.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 331, + 148, + 402, + 156 + ], + "lines": [ + { + "bbox": [ + 331, + 148, + 402, + 156 + ], + "spans": [ + { + "bbox": [ + 331, + 148, + 402, + 156 + ], + "type": "text", + "content": "(d) Shared classifier." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_footnote" + }, + { + "bbox": [ + 459, + 148, + 506, + 157 + ], + "lines": [ + { + "bbox": [ + 459, + 148, + 506, + 157 + ], + "spans": [ + { + "bbox": [ + 459, + 148, + 506, + 157 + ], + "type": "text", + "content": "(e) MixClip+." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 48, + 231, + 287, + 335 + ], + "blocks": [ + { + "bbox": [ + 46, + 176, + 547, + 199 + ], + "lines": [ + { + "bbox": [ + 46, + 176, + 547, + 199 + ], + "spans": [ + { + "bbox": [ + 46, + 176, + 547, + 199 + ], + "type": "text", + "content": "Table 1: Ablation Experiments. We conduct detailed ablation on (a): Segment number, (b): Future queries renewing, (c): Future supervision, (d): Shared classifier, and (e): MixClip+. The gray rows denote default choices." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 66, + 218, + 284, + 229 + ], + "lines": [ + { + "bbox": [ + 66, + 218, + 284, + 229 + ], + "spans": [ + { + "bbox": [ + 66, + 218, + 284, + 229 + ], + "type": "text", + "content": "long short future interaction " + }, + { + "bbox": [ + 66, + 218, + 284, + 229 + ], + "type": "inline_equation", + "content": "N_{t}" + }, + { + "bbox": [ + 66, + 218, + 284, + 229 + ], + "type": "text", + "content": " detection anticipation" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 231, + 287, + 335 + ], + "lines": [ + { + "bbox": [ + 48, + 231, + 287, + 335 + ], + "spans": [ + { + "bbox": [ + 48, + 231, + 287, + 335 + ], + "type": "table", + "html": "
(a)--67.6+0.053.7+0.0
(b)✓CA168.3+0.754.7+1.0
(c)✓✓CA168.9+1.355.3+1.6
(d)✓✓CA168.6+1.055.8+2.1
(e)✓✓CA169.2+1.656.1+2.4
(f)✓✓✓Avg&Cat168.3+0.755.3+1.6
(g)✓✓✓CA169.9+2.356.6+2.9
(h)✓✓✓CA270.4+2.957.3+3.6
(i)✓✓✓CA370.2+2.657.1+3.4
", + "image_path": "d38deab0355a795f5ad40b3abe6a4e232b2984ce14234042c691ee63227ff13d.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_body" + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 342, + 287, + 376 + ], + "lines": [ + { + "bbox": [ + 46, + 342, + 287, + 376 + ], + "spans": [ + { + "bbox": [ + 46, + 342, + 287, + 376 + ], + "type": "text", + "content": "Table 2: Ablation study on the information stream, interaction method, and times for Conditional Circular Interaction. The shallow gray row denotes the baseline setting without any interaction." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 388, + 287, + 424 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 388, + 287, + 424 + ], + "spans": [ + { + "bbox": [ + 46, + 388, + 287, + 424 + ], + "type": "text", + "content": "tion [51], and token dropping [21]. We compare these strategies, recorded in the supplementary material, and find that the top-k selection yields the best performance." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 46, + 425, + 287, + 520 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 425, + 287, + 520 + ], + "spans": [ + { + "bbox": [ + 46, + 425, + 287, + 520 + ], + "type": "text", + "content": "MixClip+. TesTra [67] proposed an augmentation technique called MixClip to solve over-fitting caused by large long-term memory. Unlike long-term memory which presents an abstract concept, short-term memory provides a continuous motion trend, often playing a decisive role in anticipation. It leads to the fact that MixClip damages the continuity of motion, thereby, does not apply to short-term memory. We propose MixClip+ to solve the issue." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 46, + 521, + 287, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 521, + 287, + 604 + ], + "spans": [ + { + "bbox": [ + 46, + 521, + 287, + 604 + ], + "type": "text", + "content": "In addition to mixing augmentation for long-term memory, we mix each feature token of short-term memory with a random clip from different videos. To maintain the continuity of short-term memory, we adopt soft fusion with hyperparameter " + }, + { + "bbox": [ + 46, + 521, + 287, + 604 + ], + "type": "inline_equation", + "content": "\\alpha = 0.25" + }, + { + "bbox": [ + 46, + 521, + 287, + 604 + ], + "type": "text", + "content": " to mix features and the corresponding labels, similar to Mixup [64]. Due to space limitations, we will describe this part in the supplementary material." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 47, + 611, + 141, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 611, + 141, + 624 + ], + "spans": [ + { + "bbox": [ + 47, + 611, + 141, + 624 + ], + "type": "text", + "content": "5.3. Ablation Study" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 46, + 629, + 287, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 287, + 677 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 287, + 677 + ], + "type": "text", + "content": "Now we analyze the MAT model, using the two-stream features pretrained on ActivityNet v1.3 and THUMOS'14 test set as the test bed. Furthermore, we also study the contribution of the proposed MixClip+ on EPIC-Kitchens-100." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "type": "text", + "content": "Segment Number. We evaluate the effect of segment number " + }, + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "N_{s}" + }, + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "type": "text", + "content": " for long-term memory compression in Table 1a. We find even a small " + }, + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "N_{s}" + }, + { + "bbox": [ + 46, + 677, + 287, + 713 + ], + "type": "text", + "content": " can improve performance, com" + } + ] + } + ], + "index": 19 + }, + { + "type": "image", + "bbox": [ + 316, + 220, + 537, + 340 + ], + "blocks": [ + { + "bbox": [ + 316, + 220, + 537, + 340 + ], + "lines": [ + { + "bbox": [ + 316, + 220, + 537, + 340 + ], + "spans": [ + { + "bbox": [ + 316, + 220, + 537, + 340 + ], + "type": "image", + "image_path": "ffbb725d7783c022603e6a70b4e982b6c1d6ed63f69633601c8feb82760f765a.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 306, + 351, + 545, + 373 + ], + "lines": [ + { + "bbox": [ + 306, + 351, + 545, + 373 + ], + "spans": [ + { + "bbox": [ + 306, + 351, + 545, + 373 + ], + "type": "text", + "content": "Figure 5: Generating latent anticipation with different anticipation length " + }, + { + "bbox": [ + 306, + 351, + 545, + 373 + ], + "type": "inline_equation", + "content": "T_{F}" + }, + { + "bbox": [ + 306, + 351, + 545, + 373 + ], + "type": "text", + "content": " and numbers of learnable tokens " + }, + { + "bbox": [ + 306, + 351, + 545, + 373 + ], + "type": "inline_equation", + "content": "N_{F}" + }, + { + "bbox": [ + 306, + 351, + 545, + 373 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_caption" + } + ], + "index": 20 + }, + { + "bbox": [ + 305, + 388, + 545, + 435 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 388, + 545, + 435 + ], + "spans": [ + { + "bbox": [ + 305, + 388, + 545, + 435 + ], + "type": "text", + "content": "pared with two-stage compression [58]. However, too many segments result in too little information within each segment to effectively capture temporal dependency. We use " + }, + { + "bbox": [ + 305, + 388, + 545, + 435 + ], + "type": "inline_equation", + "content": "N_{s} = 8" + }, + { + "bbox": [ + 305, + 388, + 545, + 435 + ], + "type": "text", + "content": " as the default in the following ablation experiments." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "spans": [ + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "text", + "content": "Query Number and Anticipation Length. Fig 5 compares generating latent anticipation using " + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "inline_equation", + "content": "N_{F}" + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "text", + "content": " learnable tokens with different anticipation lengths " + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "inline_equation", + "content": "T_{F}" + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "text", + "content": ". The experimental results indicate that, for " + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "inline_equation", + "content": "T_{F} \\leq 4" + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "text", + "content": ", a larger " + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "inline_equation", + "content": "N_{F}" + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "text", + "content": " yields superior results owing to strongly correlated semantics of short-term memory and short-term anticipation thus, the model can benefit from more tokens. We observe that " + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "inline_equation", + "content": "N_{F} = 8,16,32" + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "text", + "content": " exhibits a similar trend in the accuracy curve, with the model achieving optimal performance with " + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "inline_equation", + "content": "N_{F} = 32" + }, + { + "bbox": [ + 304, + 437, + 546, + 581 + ], + "type": "text", + "content": ". This suggests that long-term anticipation is more adaptable for sparse tokens. The observations imply that anticipation is also suitable for long- and short-term modeling." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 304, + 581, + 545, + 688 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 581, + 545, + 688 + ], + "spans": [ + { + "bbox": [ + 304, + 581, + 545, + 688 + ], + "type": "text", + "content": "Future Queries Renewal. As Section 4.2 outlines, renewing future queries before the initial interaction improves performance. In Table 1b, we compare different renewing times (\"0\" denotes no renewal and utilizes " + }, + { + "bbox": [ + 304, + 581, + 545, + 688 + ], + "type": "inline_equation", + "content": "F_{A}" + }, + { + "bbox": [ + 304, + 581, + 545, + 688 + ], + "type": "text", + "content": "). A plausible explanation is that, in the first interaction process, the interaction from anticipation to memory adjusts the old memory, causing its domain to shift largely, which leads to insufficient interaction from the new memory to the initial anticipation feature." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 713 + ], + "type": "text", + "content": "Future Supervision. In addition, we carry out diverse experiments to determine the optimal choice of future su" + } + ] + } + ], + "index": 25 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13829" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 70, + 552, + 237 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 552, + 237 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 552, + 237 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 552, + 237 + ], + "type": "table", + "html": "
MethodModalityInitOverallUnseenTail
VerbNounActionVerbNounActionVerbNounAction
RULSTM [14]RGBIN-1K27.529.013.329.823.813.119.921.410.6
AVT [17]IN-1K27.230.713.6------
AVT [17]IN-21K30.231.714.9------
DCR [59]IN-1K31.031.114.6------
TeSTra [67]IN-1K26.836.217.027.130.113.319.328.613.7
MAT (Ours)IN-1K32.739.718.831.732.112.725.732.416.0
RULSTM [14]RGB + OF + OBJIN-1K27.830.814.028.827.214.219.822.011.1
TempAgg [44]IN-1K23.231.414.728.026.214.514.522.514.8
AVT+ [17]IN-1K25.531.814.825.523.611.518.525.812.6
AVT+ [17]IN-21K28.232.015.929.526.012.823.229.214.1
TeSTra [67]RGB + OFIN-1K30.835.817.629.626.012.823.229.214.2
MAT (Ours)IN-1K35.038.819.532.530.313.828.733.116.9
", + "image_path": "d3264aa79738dd5262425a3599da896fcb0ec00ebdbbf5f6a452e28b0b4cf3cc.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 50, + 277, + 282, + 362 + ], + "blocks": [ + { + "bbox": [ + 47, + 245, + 546, + 269 + ], + "lines": [ + { + "bbox": [ + 47, + 245, + 546, + 269 + ], + "spans": [ + { + "bbox": [ + 47, + 245, + 546, + 269 + ], + "type": "text", + "content": "Table 3: Comparison to prior work on EPIC-Kitchens-100 Action Anticipation [9]. Accuracy measured by class-mean recall@5(%) following the standard protocol." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 277, + 282, + 362 + ], + "lines": [ + { + "bbox": [ + 50, + 277, + 282, + 362 + ], + "spans": [ + { + "bbox": [ + 50, + 277, + 282, + 362 + ], + "type": "table", + "html": "
ModalityEncoderInitFTOverallUnseenTail
RGBTSNIN-1K✓18.812.716.0
RGB + OFTSNIN-1K✓19.513.816.9
RGBViT-LK40019.116.216.1
RGB (V)ViT-LEgo4D21.919.418.5
RGB (N)ViT-LEgo4D24.221.420.9
RGB (V + N)ViT-LEgo4D24.621.421.2
", + "image_path": "fd1b601f950f08e55a4237abd873982195f1d4bec7ebd980c122d3ffd62ff290.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 424, + 287, + 532 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 424, + 287, + 532 + ], + "spans": [ + { + "bbox": [ + 46, + 424, + 287, + 532 + ], + "type": "text", + "content": "persion, as illustrated in Table 1c. We investigate two methods, namely future feature supervision and future label supervision. The results suggest that, compared to feature supervision, label supervision yields superior accuracy by incorporating stronger semantics derived from manual annotation. Furthermore, we explore the significance of deep supervision, i.e., multi-stage supervision. We observe that introducing multiple supervisions of real action labels improves performance." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 533, + 288, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 533, + 288, + 641 + ], + "spans": [ + { + "bbox": [ + 46, + 533, + 288, + 641 + ], + "type": "text", + "content": "Shared Classifier. In Table 1d, we exploit the classifier design in deep supervision for short-term memory and anticipation. We observe that sharing classifier parameters separately for them yields better performance. When we use a full-shared classifier for memory and anticipation, sharing all feature samples between them leads to the best performance. These results indicate that all yielded features in the interaction processes enrich the feature samples to be classified, reaching a function similar to the data augmentation." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 653, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 653, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 653, + 288, + 715 + ], + "type": "text", + "content": "Conditional Circular Interaction. Table 2 compares conditional circular interaction incorporating different interaction information streams, methods, and times. From (a) to (e), our experimental results demonstrate that the model's classification performance improves with the in" + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 316, + 278, + 537, + 389 + ], + "blocks": [ + { + "bbox": [ + 47, + 370, + 287, + 415 + ], + "lines": [ + { + "bbox": [ + 47, + 370, + 287, + 415 + ], + "spans": [ + { + "bbox": [ + 47, + 370, + 287, + 415 + ], + "type": "text", + "content": "Table 4: Exploring different visual encoders for EK100 action anticipation. V or N denotes the encoder is pretrained on verb or noun subset [5]. \"FT\" is that the encoder is fine-tuned on the classification task of EK100." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 316, + 278, + 537, + 389 + ], + "lines": [ + { + "bbox": [ + 316, + 278, + 537, + 389 + ], + "spans": [ + { + "bbox": [ + 316, + 278, + 537, + 389 + ], + "type": "table", + "html": "
MethodTHUMOS'14TVSeries
KineticsANetKineticsANet
RED [15]-37.575.1-
TRN [57]-38.975.7-
OadTR [54]53.545.977.879.1
LSTR [58]52.650.180.8-
GateHUB [7]-54.282.0-
TesTra [67]56.855.3--
MAT (ours)58.257.382.681.5
", + "image_path": "247fe4e160204479b8c27fd26e5de583ebef9aa32b8fee3e77add1ffff432aad.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 397, + 546, + 430 + ], + "lines": [ + { + "bbox": [ + 305, + 397, + 546, + 430 + ], + "spans": [ + { + "bbox": [ + 305, + 397, + 546, + 430 + ], + "type": "text", + "content": "Table 5: Action anticipation result on THUMOS'14 and TVSeries, mAP is reported for THUMOS'14 and mcAP for TVSeries." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 448, + 545, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 448, + 545, + 628 + ], + "spans": [ + { + "bbox": [ + 304, + 448, + 545, + 628 + ], + "type": "text", + "content": "creasing richness of interaction information. Moreover, we observe that latent information in the future is equally or even more critical to classify the current action than information from the distant past, as evidenced by the performance comparison between (c) and (e). We also investigate the effect of different interaction mechanisms, comparing (f) and (g), and the results indicate that the cross-attention (CA) mechanism outperforms average pooling and concatenation similar to [54], achieving a " + }, + { + "bbox": [ + 304, + 448, + 545, + 628 + ], + "type": "inline_equation", + "content": "2.1\\%" + }, + { + "bbox": [ + 304, + 448, + 545, + 628 + ], + "type": "text", + "content": " higher accuracy. Lastly, we evaluate the impact of different interaction times " + }, + { + "bbox": [ + 304, + 448, + 545, + 628 + ], + "type": "inline_equation", + "content": "N_{t}" + }, + { + "bbox": [ + 304, + 448, + 545, + 628 + ], + "type": "text", + "content": ", as illustrated by (g), (h), and (i). The experimental results reveal that the model's performance improves gradually with the increase of " + }, + { + "bbox": [ + 304, + 448, + 545, + 628 + ], + "type": "inline_equation", + "content": "N_{t}" + }, + { + "bbox": [ + 304, + 448, + 545, + 628 + ], + "type": "text", + "content": ". Notably, the model attains its highest performance when interacting with all information " + }, + { + "bbox": [ + 304, + 448, + 545, + 628 + ], + "type": "inline_equation", + "content": "N_{t} = 2" + }, + { + "bbox": [ + 304, + 448, + 545, + 628 + ], + "type": "text", + "content": " times." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": "MixClip+ for Anticipation. Table 1e presents the augmentation efficacy of MixClip+ or MixClip on long- and short-term memory. Notably, the baseline experiences a significant drop in action recall to " + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "inline_equation", + "content": "18.1\\%" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": " without data augmentation. However, the result is still significantly better than Testra [67] with MixClip (" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "inline_equation", + "content": "18.1\\%" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": " vs " + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "inline_equation", + "content": "17.6\\%" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": "), as shown in Table 3. Furthermore, the results in row 3 reveal that MixClip" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "13830" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 70, + 550, + 167 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 550, + 167 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 550, + 167 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 550, + 167 + ], + "type": "table", + "html": "
MethodAugmentationOverallUnseenTail
LongShortVerbNounActionVerbNounActionVerbNounAction
LSTR‡[58]--39.644.122.634.335.318.739.041.620.7
TesTra‡[67]--40.044.823.234.636.019.039.442.120.9
MAT (ours)--41.846.124.936.537.920.140.843.222.8
TesTra‡[67]MixClip-39.745.625.136.337.219.239.042.422.2
MAT (ours)MixClip-42.647.325.938.337.619.741.844.023.1
MAT (ours)MixClipMixClip+44.548.326.339.938.120.343.446.623.7
", + "image_path": "4f0f9bfd0659ea569af65074301161f710a260044f7cb4697ae22b4aa45723b5.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 49, + 208, + 284, + 383 + ], + "blocks": [ + { + "bbox": [ + 46, + 175, + 546, + 198 + ], + "lines": [ + { + "bbox": [ + 46, + 175, + 546, + 198 + ], + "spans": [ + { + "bbox": [ + 46, + 175, + 546, + 198 + ], + "type": "text", + "content": "Table 6: Online action detection result on EPIC-Kitchens-100. Accuracy is measured by class-mean recall@5%. ‡ was reproduced by us because LSTR [58] and TesTra [67] did not report the result." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 49, + 208, + 284, + 383 + ], + "lines": [ + { + "bbox": [ + 49, + 208, + 284, + 383 + ], + "spans": [ + { + "bbox": [ + 49, + 208, + 284, + 383 + ], + "type": "table", + "html": "
MethodArchTHUMOS'14TVSeriesHDD
KineticsANetKineticsANetSensor
CDC [45]CNN-44.4---
RED [15]RNN-45.3-79.227.4
TRN [57]RNN62.147.286.283.729.2
IDN [12]RNN60.350.086.184.7-
LAP [34]RNN-53.3-85.3-
PKD [66]CNN64.5-86.4--
WOAD [16]RNN67.1----
OadTR [54]Trans65.258.387.285.429.8
Colar [61]Trans66.959.488.186.030.6
LSTR [58]Trans69.565.389.188.1-
GateHUB [7]Trans70.769.189.688.432.1
TeSTra [67]Trans71.268.2---
MAT (Ours)Trans71.670.489.788.632.7
", + "image_path": "de8cdbdf5346165ce70f141b06059d5a8aa721f5173187cd153873b4f0f25598.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 392, + 287, + 437 + ], + "lines": [ + { + "bbox": [ + 46, + 392, + 287, + 437 + ], + "spans": [ + { + "bbox": [ + 46, + 392, + 287, + 437 + ], + "type": "text", + "content": "Table 7: Online action detection performances on THUMOS'14 [30], TVSeries [10], and HDD [42]. The mAP performance is reported for THUMOS'14 and HDD, while the mcAP is reported for TVSeries." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 449, + 287, + 557 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 449, + 287, + 557 + ], + "spans": [ + { + "bbox": [ + 46, + 449, + 287, + 557 + ], + "type": "text", + "content": "is not suited for short-term memory, as it cannot improve performance and may even degrade the results regarding the verb (32.1% vs 31.0%). However, the model achieves the best performance (19.5%) when performing MixClip and MixClip+ augmentation separately on long- and short-term memory. Moreover, we validate the augmentation of double-MixClip+ (in row 5) on long- and short-term memory and observe that the overall gain of the model is small, similar to double-MixClip (in row 3)." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 563, + 272, + 576 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 563, + 272, + 576 + ], + "spans": [ + { + "bbox": [ + 47, + 563, + 272, + 576 + ], + "type": "text", + "content": "5.4. Comparison with State-of-the-Art Methods" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": "Action Anticipation. We compare MAT with prior methods on EPIC-Kitchens-100 for action anticipation, as shown in Table 3. We divide the experimental results into two parts, one part of the input modality is RGB, and the other is multi-modal input, such as optical flow and object features. Using the ImageNet-1K pretrained features, MAT significantly outperforms RULSTM [14], AVT [17], and TeSTra [67] on terms of verb, noun, and action (at least " + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "inline_equation", + "content": "2.5\\%" + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "inline_equation", + "content": "3.0\\%" + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "inline_equation", + "content": "1.8\\%" + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": ", respectively). MAT with RGB and optical flow features achieves " + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "inline_equation", + "content": "1.8\\%" + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": " higher action recall than TeSTra with the same input, which can better reflect the ef" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 210, + 470, + 222 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 210, + 470, + 222 + ], + "spans": [ + { + "bbox": [ + 305, + 210, + 470, + 222 + ], + "type": "text", + "content": "fectiveness of the modules we designed." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 222, + 545, + 461 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 222, + 545, + 461 + ], + "spans": [ + { + "bbox": [ + 304, + 222, + 545, + 461 + ], + "type": "text", + "content": "In Table 4, we conduct an extensive analysis of the impact of various visual encoders on the performance of action anticipation. In particular, we leverage the ViT architecture [11], which is pre-trained on the largest egocentric dataset Ego4D [19], made available by [5], owing to its superior performance in Ego4D Challenges. Additionally, to compare the impact of first-person and third-person pretraining, we utilize the weights pretrained on the K400 [31], provided by VideoMAE [47]. The results suggest that encoders pre-trained on first-person datasets perform better than on widely-used third-person datasets. Moreover, leveraging the noun subset brings a huge performance boost, comparing pretraining on the verb subset of the Ego4D dataset. We suppose the noun subset with more object categories (the verb and noun subset include 118 and 582 categories) encourages the encoder to search more complex visual semantics. It highlights the critical role of egocentric perspective upstream pretraining method [38, 68] and diverse semantic annotations [19, 9, 29], which could have far-reaching implications for egocentric research." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 461, + 546, + 581 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 461, + 546, + 581 + ], + "spans": [ + { + "bbox": [ + 304, + 461, + 546, + 581 + ], + "type": "text", + "content": "Following previous works [58, 7, 67], we further evaluate MAT on action anticipation tasks for THUMOS'14 and TVSeries. Unlike the previous work that required additional learnable tokens, we take the corresponding tokens from " + }, + { + "bbox": [ + 304, + 461, + 546, + 581 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_A" + }, + { + "bbox": [ + 304, + 461, + 546, + 581 + ], + "type": "text", + "content": " for forecasting. Table 5 shows that using the ActivityNet pretrained features, MAT significantly outperforms the existing methods by " + }, + { + "bbox": [ + 304, + 461, + 546, + 581 + ], + "type": "inline_equation", + "content": "2.0\\%" + }, + { + "bbox": [ + 304, + 461, + 546, + 581 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 461, + 546, + 581 + ], + "type": "inline_equation", + "content": "0.6\\%" + }, + { + "bbox": [ + 304, + 461, + 546, + 581 + ], + "type": "text", + "content": " on THUMOS'14 and TVSeries, respectively. Moreover, the performance of MAT can also be further improved when pretraining on Kinetics." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "type": "text", + "content": "Online Action Detection. We also compare MAT with other state-of-the-art online action detection methods [57, 58, 54, 61, 7] on THUMOS'14, TVSeries, and HDD. As illustrated in Table 7, our MAT achieves state-of-the-art performance and improves mAP by " + }, + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "type": "inline_equation", + "content": "2.2\\%" + }, + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "type": "text", + "content": " on the THUMOS'14 dataset under the TSN-Anet feature input, and " + }, + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "type": "inline_equation", + "content": "0.4\\%" + }, + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "type": "text", + "content": " under the TSN-Kinetics feature. For TVSeries, MAT is slightly better than GateHUB by " + }, + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "type": "inline_equation", + "content": "0.1\\%" + }, + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "type": "text", + "content": " Furthermore, MAT achieves " + }, + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "type": "inline_equation", + "content": "0.6\\%" + }, + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "type": "text", + "content": " better than the state-of-the-art GateHUB " + }, + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "type": "inline_equation", + "content": "(32.1\\%)" + }, + { + "bbox": [ + 304, + 582, + 545, + 700 + ], + "type": "text", + "content": " method on HDD." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 318, + 701, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 318, + 701, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 318, + 701, + 545, + 713 + ], + "type": "text", + "content": "To further verify the effect of MAT, in Table 6, we offer" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13831" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 71, + 288, + 165 + ], + "blocks": [ + { + "bbox": [ + 48, + 71, + 288, + 165 + ], + "lines": [ + { + "bbox": [ + 48, + 71, + 288, + 165 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 288, + 165 + ], + "type": "table", + "html": "
Method#ParamFPSmAP
Optical FlowRGB FeatFlow FeatModelTotal
TRN402.9 M8.170.514.6123.38.147.2
OadTR75.8 M8.170.514.6110.08.158.3
LSTR58.0 M8.170.514.691.68.165.3
GateHUB45.2 M8.170.514.671.28.169.1
MAT (Ours)94.6 M8.170.514.672.68.170.4
", + "image_path": "37eefcc05c094367545c758271205dd7da024abf161ff7c275c5723b2a3cbeda.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 175, + 287, + 198 + ], + "lines": [ + { + "bbox": [ + 47, + 175, + 287, + 198 + ], + "spans": [ + { + "bbox": [ + 47, + 175, + 287, + 198 + ], + "type": "text", + "content": "Table 8: Efficiency comparison between MAT and the previous work on parameter (M) and inference speed (FPS)" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "type": "image", + "bbox": [ + 48, + 209, + 288, + 269 + ], + "blocks": [ + { + "bbox": [ + 48, + 209, + 288, + 269 + ], + "lines": [ + { + "bbox": [ + 48, + 209, + 288, + 269 + ], + "spans": [ + { + "bbox": [ + 48, + 209, + 288, + 269 + ], + "type": "image", + "image_path": "5e6aabeedaa545e85a5a2cd69515be16a1599679ee3ea7ca1d29ae19eb8414ba.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 277, + 287, + 310 + ], + "lines": [ + { + "bbox": [ + 47, + 277, + 287, + 310 + ], + "spans": [ + { + "bbox": [ + 47, + 277, + 287, + 310 + ], + "type": "text", + "content": "Figure 6: Visualization of MAT's online prediction. The curves indicate the predicted confidence of the ground-truth class (High-Jump) with LSTR and our method." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 324, + 287, + 469 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 324, + 287, + 469 + ], + "spans": [ + { + "bbox": [ + 46, + 324, + 287, + 469 + ], + "type": "text", + "content": "the results for online action detection on the EK100 dataset. We divide the experimental results into two parts: one does not use augmentation, and the other uses MixClip or MixClip+. The results show that MAT surpasses the previous method by a large margin whether or not to use data augmentation. It is worth noting that when performing online action detection, we only need to take out the corresponding token in the short-term memory " + }, + { + "bbox": [ + 46, + 324, + 287, + 469 + ], + "type": "inline_equation", + "content": "\\widehat{\\mathbf{M}}_S" + }, + { + "bbox": [ + 46, + 324, + 287, + 469 + ], + "type": "text", + "content": " for prediction. The superior performance of the model further highlights that MAT can simultaneously handle online action detection and anticipation tasks, thus integrating the two problems into a unified framework and performing excellently." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 476, + 159, + 490 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 476, + 159, + 490 + ], + "spans": [ + { + "bbox": [ + 47, + 476, + 159, + 490 + ], + "type": "text", + "content": "5.5. Efficiency Analysis" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 495, + 287, + 579 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 495, + 287, + 579 + ], + "spans": [ + { + "bbox": [ + 46, + 495, + 287, + 579 + ], + "type": "text", + "content": "Table 8 compares MAT with other methods in terms of model parameters and running time, conducted on a single Tesla V100. It is worth noting that under the same features, the efficiency bottleneck of the system remains in optical flow calculation and feature extraction. Our approach achieves a stronger performance while effectively balancing the trade-off between parameters and computational." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 587, + 167, + 601 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 587, + 167, + 601 + ], + "spans": [ + { + "bbox": [ + 47, + 587, + 167, + 601 + ], + "type": "text", + "content": "5.6. Qualitative Analysis." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 715 + ], + "type": "text", + "content": "In Fig 6, we qualitatively analyzes the proposed MAT model. The confidence in the range [0, 1] on the y-axis denotes the probability of predicting the current action, e.g., HighJump. The figure highlights our MAT's successful suppression of background and high-confidence feedback of action segments compared with LSTR. The circular interaction of memory and anticipation provides reliable semantic information for the online prediction of the model, making the model offers a more sensitive and accurate torsion signal" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 309, + 71, + 547, + 204 + ], + "blocks": [ + { + "bbox": [ + 309, + 71, + 547, + 204 + ], + "lines": [ + { + "bbox": [ + 309, + 71, + 547, + 204 + ], + "spans": [ + { + "bbox": [ + 309, + 71, + 547, + 204 + ], + "type": "image", + "image_path": "ec9224486ed73be0889e595d38aa06b1ac67a43bb56a49cf53b8009e9a8c9410.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 212, + 545, + 234 + ], + "lines": [ + { + "bbox": [ + 305, + 212, + 545, + 234 + ], + "spans": [ + { + "bbox": [ + 305, + 212, + 545, + 234 + ], + "type": "text", + "content": "Figure 7: Attention weight visualization of different attention heads." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 249, + 525, + 261 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 249, + 525, + 261 + ], + "spans": [ + { + "bbox": [ + 306, + 249, + 525, + 261 + ], + "type": "text", + "content": "on the transition between background and foreground." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 270, + 437, + 282 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 270, + 437, + 282 + ], + "spans": [ + { + "bbox": [ + 306, + 270, + 437, + 282 + ], + "type": "text", + "content": "5.7. Attention Visualization" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 289, + 547, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 289, + 547, + 361 + ], + "spans": [ + { + "bbox": [ + 304, + 289, + 547, + 361 + ], + "type": "text", + "content": "Fig 7 depicts the attention weights of the last token of the short-term memory. It can be seen that under the blessing of future perception, MAT's multi-head attention mechanism pays attention to memory and anticipation simultaneously, leading to the model not limiting in history and attaining better performance." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 369, + 471, + 380 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 369, + 471, + 380 + ], + "spans": [ + { + "bbox": [ + 306, + 369, + 471, + 380 + ], + "type": "text", + "content": "6. Conclusion and Future Work" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 388, + 546, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 388, + 546, + 616 + ], + "spans": [ + { + "bbox": [ + 304, + 388, + 546, + 616 + ], + "type": "text", + "content": "We present Memory-and-Anticipation Transformer (MAT), a novel memory-anticipation-based paradigm for online action detection and anticipation, to overcome the weakness of most existing methods that can only complete modeling temporal dependency within a limited historical context. Through extensive experiments on four challenging benchmarks across two tasks, we show its applicability in predicting present or future actions, obtaining state-of-the-art results, and demonstrating the importance of circular interaction between memory and anticipation in the entire temporal structure. Although the temporal dimension is only considered in this work, we believe MAT would be a general paradigm for any AI system used to analyze video online and predict future events. In the near future, we will validate our model on more benchmarks and extend it to the long-term anticipation task. In the longer term, we will continue to unearth the intrinsic association of memory with anticipation and develop more effective forecasting models." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 624, + 408, + 637 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 624, + 408, + 637 + ], + "spans": [ + { + "bbox": [ + 306, + 624, + 408, + 637 + ], + "type": "text", + "content": "Acknowledgements" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 641, + 547, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 547, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 547, + 712 + ], + "type": "text", + "content": "This work was supported in part by National Key R&D Program of China (No. 2022ZD0160900), National Natural Science Foundation of China (Grant No. 61672273, 61832008, 62076119), and was also supported by the Fundamental Research Funds for the Central Universities XJ2023000701 and XJ2023004101." + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13832" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 286, + 713 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 53, + 91, + 286, + 124 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 286, + 124 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 286, + 124 + ], + "type": "text", + "content": "[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lucic, and Cordelia Schmid. Vivit: A video vision transformer. In ICCV, pages 6816-6826, 2021. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 126, + 286, + 158 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 126, + 286, + 158 + ], + "spans": [ + { + "bbox": [ + 53, + 126, + 286, + 158 + ], + "type": "text", + "content": "[2] Iz Beltagy, Matthew E. Peters, and Arman Cohan. Longformer: The long-document transformer. CoRR, abs/2004.05150, 2020. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 160, + 286, + 193 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 160, + 286, + 193 + ], + "spans": [ + { + "bbox": [ + 53, + 160, + 286, + 193 + ], + "type": "text", + "content": "[3] Gedas Bertasius, Heng Wang, and Lorenzo Torresani. Is space-time attention all you need for video understanding? In ICML, volume 139, pages 813-824, 2021. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 195, + 286, + 227 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 195, + 286, + 227 + ], + "spans": [ + { + "bbox": [ + 53, + 195, + 286, + 227 + ], + "type": "text", + "content": "[4] Shuqiang Cao, Weixin Luo, Bairui Wang, Wei Zhang, and Lin Ma. A circular window-based cascade transformer for online action detection. CoRR, abs/2208.14209, 2022. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 230, + 286, + 305 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 230, + 286, + 305 + ], + "spans": [ + { + "bbox": [ + 53, + 230, + 286, + 305 + ], + "type": "text", + "content": "[5] Guo Chen, Sen Xing, Zhe Chen, Yi Wang, Kunchang Li, Yizhuo Li, Yi Liu, Jiahao Wang, Yin-Dong Zheng, Bingkun Huang, Zhiyu Zhao, Junting Pan, Yifei Huang, Zun Wang, Jiashuo Yu, Yinan He, Hongjie Zhang, Tong Lu, Yali Wang, Limin Wang, and Yu Qiao. Internvideo-ego4d: A pack of champion solutions to ego4d challenges. CoRR, abs/2211.09529, 2022. 7, 8" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 308, + 286, + 361 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 308, + 286, + 361 + ], + "spans": [ + { + "bbox": [ + 53, + 308, + 286, + 361 + ], + "type": "text", + "content": "[6] Guo Chen, Yin-Dong Zheng, Jiahao Wang, Jilan Xu, Yifei Huang, Junting Pan, Yi Wang, Yali Wang, Yu Qiao, Tong Lu, and Limin Wang. Videollm: Modeling video sequence with large language models. CoRR, abs/2305.13292, 2023. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 364, + 286, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 364, + 286, + 407 + ], + "spans": [ + { + "bbox": [ + 53, + 364, + 286, + 407 + ], + "type": "text", + "content": "[7] Junwen Chen, Gaurav Mittal, Ye Yu, Yu Kong, and Mei Chen. Gatehub: Gated history unit with background suppression for online action detection. In CVPR, pages 19925-19934, 2022. 1, 2, 7, 8" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 410, + 286, + 442 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 410, + 286, + 442 + ], + "spans": [ + { + "bbox": [ + 53, + 410, + 286, + 442 + ], + "type": "text", + "content": "[8] MMAction2 Contributors. Openmmlab's next generation video understanding toolbox and benchmark. https://github.com/open-mmlab/mmaction2, 2020.5" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 445, + 286, + 520 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 445, + 286, + 520 + ], + "spans": [ + { + "bbox": [ + 53, + 445, + 286, + 520 + ], + "type": "text", + "content": "[9] Dima Damen, Hazel Doughty, Giovanni Maria Farinella, Antonino Furnari, Jian Ma, Evangelos Kazakos, Davide Moltisanti, Jonathan Munro, Toby Perrett, Will Price, and Michael Wray. Rescaling egocentric vision: Collection, pipeline and challenges for epic-kitchens-100. International Journal of Computer Vision (IJCV), 130:33-55, 2022. 2, 3, 5, 7, 8" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 522, + 286, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 522, + 286, + 555 + ], + "spans": [ + { + "bbox": [ + 48, + 522, + 286, + 555 + ], + "type": "text", + "content": "[10] Roeland De Geest, Efstratios Gavves, Amir Ghodrati, Zhenyang Li, Cees Snoek, and Tinne Tuytelaars. Online action detection. In ECCV, pages 269-284, 2016. 1, 2, 5, 8" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 557, + 286, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 557, + 286, + 643 + ], + "spans": [ + { + "bbox": [ + 48, + 557, + 286, + 643 + ], + "type": "text", + "content": "[11] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. In 9th International Conference on Learning Representations, ICLR 2021, Virtual Event, Austria, May 3-7, 2021. OpenReview.net, 2021. 2, 8" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 646, + 286, + 688 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 646, + 286, + 688 + ], + "spans": [ + { + "bbox": [ + 48, + 646, + 286, + 688 + ], + "type": "text", + "content": "[12] Hyunjun Eun, Jinyoung Moon, Jongyoul Park, Chanho Jung, and Changick Kim. Learning to discriminate information for online action detection. In CVPR, pages 806-815, 2020. 2, 8" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 691, + 286, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 286, + 713 + ], + "type": "text", + "content": "[13] Haoqi Fan, Bo Xiong, Karttikeya Mangalam, Yanghao Li, Zhicheng Yan, Jitendra Malik, and Christoph Feichtenhofer." + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 24, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 116 + ], + "type": "text", + "content": "Multiscale vision transformers. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 6804-6815. IEEE, 2021. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 118, + 545, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 118, + 545, + 161 + ], + "spans": [ + { + "bbox": [ + 308, + 118, + 545, + 161 + ], + "type": "text", + "content": "[14] Antonino Furnari and Giovanni Maria Farinella. What would you expect? anticipating egocentric actions with rolling-unrolling lstms and modality attention. In International Conference on Computer Vision (ICCV), 2019. 1, 2, 5, 7, 8" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 163, + 545, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 163, + 545, + 194 + ], + "spans": [ + { + "bbox": [ + 308, + 163, + 545, + 194 + ], + "type": "text", + "content": "[15] Jiyang Gao, Zhenheng Yang, and Ram Nevatia. RED: reinforced encoder-decoder networks for action anticipation. In BMVC, 2017. 2, 7, 8" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 196, + 545, + 237 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 196, + 545, + 237 + ], + "spans": [ + { + "bbox": [ + 308, + 196, + 545, + 237 + ], + "type": "text", + "content": "[16] Mingfei Gao, Yingbo Zhou, Ran Xu, Richard Socher, and Caiming Xiong. WOAD: weakly supervised online action detection in untrimmed videos. In CVPR, pages 1915-1923, 2021. 2, 8" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 240, + 545, + 261 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 240, + 545, + 261 + ], + "spans": [ + { + "bbox": [ + 308, + 240, + 545, + 261 + ], + "type": "text", + "content": "[17] Rohit Girdhar and Kristen Grauman. Anticipative Video Transformer. In ICCV, 2021. 1, 2, 5, 7, 8" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 263, + 545, + 327 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 263, + 545, + 327 + ], + "spans": [ + { + "bbox": [ + 308, + 263, + 545, + 327 + ], + "type": "text", + "content": "[18] Rohit Girdhar, Mannat Singh, Nikhila Ravi, Laurens van der Maaten, Armand Joulin, and Ishan Misra. Omnivore: A single model for many visual modalities. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New Orleans, LA, USA, June 18-24, 2022, pages 16081-16091. IEEE, 2022. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 329, + 545, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 329, + 545, + 635 + ], + "spans": [ + { + "bbox": [ + 308, + 329, + 545, + 635 + ], + "type": "text", + "content": "[19] Kristen Grauman, Andrew Westbury, Eugene Byrne, Zachary Chavis, Antonino Furnari, Rohit Girdhar, Jackson Hamburger, Hao Jiang, Miao Liu, Xingyu Liu, Miguel Martin, Tushar Nagarajan, Ilija Radosavovic, Santhosh Kumar Ramakrishnan, Fiona Ryan, Jayant Sharma, Michael Wray, Mengmeng Xu, Eric Zhongcong Xu, Chen Zhao, Siddhant Bansal, Dhruv Batra, Vincent Cartillier, Sean Crane, Tien Do, Morrie Doulaty, Akshay Erapalli, Christoph Feichtenhofer, Adriano Fragomeni, Qichen Fu, Abrham Gebreselasie, Cristina Gonzalez, James Hillis, Xuhua Huang, Yifei Huang, Wenqi Jia, Wesley Khoo, Jachym Kolár, Satwik Kottur, Anurag Kumar, Federico Landini, Chao Li, Yanghao Li, Zhenqiang Li, Karttikeya Mangalam, Raghava Modhugu, Jonathan Munro, Tullie Murrell, Takumi Nishiyasu, Will Price, Paola Ruiz Puentes, Merey Ramazanova, Leda Sari, Kiran Somasundaram, Audrey Southerland, Yusuke Sugano, Ruijie Tao, Minh Vo, Yuchen Wang, Xindi Wu, Takuma Yagi, Ziwei Zhao, Yunyi Zhu, Pablo Arbeláez, David Crandall, Dima Damen, Giovanni Maria Farinella, Christian Fuegen, Bernard Ghanem, Vamsi Krishna Ithapu, C. V. Jawahar, Hanbyul Joo, Kris Kitani, Haizhou Li, Richard A. Newcombe, Aude Oliva, Hyun Soo Park, James M. Rehg, Yoichi Sato, Jianbo Shi, Mike Zheng Shou, Antonio Torralba, Lorenzo Torresani, Mingfei Yan, and Jitendra Malik. Ego4d: Around the world in 3,000 hours of egocentric video. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New Orleans, LA, USA June 18-24, 2022 pages 18973-18990. IEEE, 2022. 8" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 636, + 545, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 636, + 545, + 668 + ], + "spans": [ + { + "bbox": [ + 308, + 636, + 545, + 668 + ], + "type": "text", + "content": "[20] Demis Hassabis, Dharshan Kumaran, Christopher Summerfield, and Matthew Botvinick. Neuroscience-inspired artificial intelligence. Neuron, 95(2):245-258, 2017. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 670, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 670, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 670, + 545, + 713 + ], + "type": "text", + "content": "[21] Kaiming He, Xinlei Chen, Saining Xie, Yanghao Li, Piotr Dólar, and Ross B. Girshick. Masked autoencoders are scalable vision learners. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New" + } + ] + } + ], + "index": 23 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "13833" + } + ] + } + ], + "index": 25 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 67, + 72, + 286, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 286, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 286, + 95 + ], + "type": "text", + "content": "Orleans, LA, USA, June 18-24, 2022, pages 15979-15988. IEEE, 2022. 6" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 95, + 287, + 128 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 95, + 287, + 128 + ], + "spans": [ + { + "bbox": [ + 48, + 95, + 287, + 128 + ], + "type": "text", + "content": "[22] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In CVPR, pages 770-778, 2016. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 129, + 287, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 129, + 287, + 173 + ], + "spans": [ + { + "bbox": [ + 48, + 129, + 287, + 173 + ], + "type": "text", + "content": "[23] Fabian Caba Heilbron, Victor Escorcia, Bernard Ghanem, and Juan Carlos Niebles. Activitynet: A large-scale video benchmark for human activity understanding. In CVPR, pages 961-970, 2015. 5" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 173, + 287, + 216 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 173, + 287, + 216 + ], + "spans": [ + { + "bbox": [ + 48, + 173, + 287, + 216 + ], + "type": "text", + "content": "[24] Geoffrey E. Hinton, Nitish Srivastava, Alex Krizhevsky, Ilya Sutskever, and Ruslan Salakhutdinov. Improving neural networks by preventing co-adaptation of feature detectors. CoRR, abs/1207.0580, 2012. 5" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 217, + 287, + 259 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 217, + 287, + 259 + ], + "spans": [ + { + "bbox": [ + 48, + 217, + 287, + 259 + ], + "type": "text", + "content": "[25] Yifei Huang, Minjie Cai, Zhenqiang Li, Feng Lu, and Yoichi Sato. Mutual context network for jointly estimating egocentric gaze and action. IEEE Transactions on Image Processing, 29:7795-7806, 2020. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 261, + 287, + 315 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 261, + 287, + 315 + ], + "spans": [ + { + "bbox": [ + 48, + 261, + 287, + 315 + ], + "type": "text", + "content": "[26] Yifei Huang, Minjie Cai, Zhenqiang Li, and Yoichi Sato. Predicting gaze in egocentric video by learning task-dependent attention transition. In Proceedings of the European conference on computer vision (ECCV), pages 754-769, 2018. 1" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 316, + 287, + 360 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 316, + 287, + 360 + ], + "spans": [ + { + "bbox": [ + 48, + 316, + 287, + 360 + ], + "type": "text", + "content": "[27] Yifei Huang, Yusuke Sugano, and Yoichi Sato. Improving action segmentation via graph-based temporal reasoning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 14024-14034, 2020. 1" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 361, + 287, + 393 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 361, + 287, + 393 + ], + "spans": [ + { + "bbox": [ + 48, + 361, + 287, + 393 + ], + "type": "text", + "content": "[28] Yifei Huang, Lijin Yang, and Yoichi Sato. Compound prototype matching for few-shot action recognition. In European Conference on Computer Vision, pages 351-368, 2022. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 393, + 287, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 393, + 287, + 426 + ], + "spans": [ + { + "bbox": [ + 48, + 393, + 287, + 426 + ], + "type": "text", + "content": "[29] Baoxiong Jia, Ting Lei, Song-Chun Zhu, and Siyuan Huang. Egotaskqa: Understanding human tasks in egocentric videos. CoRR, abs/2210.03929, 2022. 8" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 426, + 287, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 426, + 287, + 470 + ], + "spans": [ + { + "bbox": [ + 48, + 426, + 287, + 470 + ], + "type": "text", + "content": "[30] Y.-G. Jiang, J. Liu, A. Roshan Zamir, G. Toderici, I. Laptev, M. Shah, and R. Sukthankar. THUMOS challenge: Action recognition with a large number of classes. http://crcv.ucf.edu/THUMOS14/, 2014. 2, 5, 8" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 471, + 287, + 525 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 471, + 287, + 525 + ], + "spans": [ + { + "bbox": [ + 48, + 471, + 287, + 525 + ], + "type": "text", + "content": "[31] Will Kay, João Carreira, Karen Simonyan, Brian Zhang, Chloe Hillier, Sudheendra Vijayanarasimhan, Fabio Viola, Tim Green, Trevor Back, Paul Natsev, Mustafa Suleyman, and Andrew Zisserman. The kinetics human action video dataset. CoRR, abs/1705.06950, 2017. 5, 8" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 525, + 287, + 581 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 525, + 287, + 581 + ], + "spans": [ + { + "bbox": [ + 48, + 525, + 287, + 581 + ], + "type": "text", + "content": "[32] Kris M Kitani, Brian D Ziebart, James Andrew Bagnell, and Martial Hebert. Activity forecasting. In Computer Vision-ECCV 2012: 12th European Conference on Computer Vision, Florence, Italy, October 7-13, 2012, Proceedings, Part IV 12, pages 201-214. Springer, 2012. 1" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 582, + 287, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 582, + 287, + 624 + ], + "spans": [ + { + "bbox": [ + 48, + 582, + 287, + 624 + ], + "type": "text", + "content": "[33] Hema S Koppula and Ashutosh Saxena. Anticipating human activities using object affordances for reactive robotic response. IEEE transactions on pattern analysis and machine intelligence, 38(1):14-29, 2015. 1" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 625, + 287, + 669 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 625, + 287, + 669 + ], + "spans": [ + { + "bbox": [ + 48, + 625, + 287, + 669 + ], + "type": "text", + "content": "[34] Sumin Lee, Hyunjun Eun, Jinyoung Moon, Seokeon Choi, Yoonhyung Kim, Chanho Jung, and Changick Kim. Learning to discriminate information for online action detection: Analysis and application. TPAMI, pages 1-17, 2022. 5, 8" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 287, + 713 + ], + "type": "text", + "content": "[35] Kunchang Li, Yali Wang, Yinan He, Yizhuo Li, Yi Wang, Limin Wang, and Yu Qiao. Uniformerv2: Spatiotemporal learning by arming image vits with video uniformer. arXiv preprint arXiv:2211.09552, 2022. 2" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 116 + ], + "type": "text", + "content": "[36] Kunchang Li, Yali Wang, Yizhuo Li, Yi Wang, Yinan He, Limin Wang, and Yu Qiao. Unmasked teacher: Towards training-efficient video foundation models. arXiv preprint arXiv:2303.16058, 2023. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 118, + 545, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 545, + 162 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 545, + 162 + ], + "type": "text", + "content": "[37] Zhiqi Li, Zhiding Yu, Wenhai Wang, Anima Anandkumar, Tong Lu, and Jose M Alvarez. Fb-bev: Bev representation from forward-backward view transformations. arXiv preprint arXiv:2308.02236, 2023. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 163, + 545, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 163, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 307, + 163, + 545, + 228 + ], + "type": "text", + "content": "[38] Kevin Qinghong Lin, Alex Jinpeng Wang, Mattia Soldan, Michael Wray, Rui Yan, Eric Zhongcong Xu, Difei Gao, Rong-Cheng Tu, Wenzhe Zhao, Weijie Kong, Chengfei Cai, Hongfa Wang, Dima Damen, Bernard Ghanem, Wei Liu, and Mike Zheng Shou. Egocentric video-language pretraining. CoRR, abs/2206.01670, 2022. 8" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 230, + 545, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 230, + 545, + 262 + ], + "spans": [ + { + "bbox": [ + 307, + 230, + 545, + 262 + ], + "type": "text", + "content": "[39] Xiaolong Liu, Qimeng Wang, Yao Hu, Xu Tang, Song Bai, and Xiang Bai. End-to-end temporal action detection with transformer. CoRR, abs/2106.10271, 2021. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 264, + 545, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 264, + 545, + 330 + ], + "spans": [ + { + "bbox": [ + 307, + 264, + 545, + 330 + ], + "type": "text", + "content": "[40] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 9992-10002. IEEE, 2021. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 331, + 545, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 331, + 545, + 374 + ], + "spans": [ + { + "bbox": [ + 307, + 331, + 545, + 374 + ], + "type": "text", + "content": "[41] Giovanni Pezzulo, Francesco Rigoli, and Karl Friston. Active inference, homeostatic regulation and adaptive behavioural control. Progress in neurobiology, 134:17-35, 2015. 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 376, + 545, + 420 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 376, + 545, + 420 + ], + "spans": [ + { + "bbox": [ + 307, + 376, + 545, + 420 + ], + "type": "text", + "content": "[42] Vasili Ramanishka, Yi-Ting Chen, Teruhisa Mitsu, and Kate Saenko. Toward driving scene understanding: A dataset for learning driver behavior and causal reasoning. In CVPR, 2018. 2, 5, 8" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 421, + 545, + 443 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 421, + 545, + 443 + ], + "spans": [ + { + "bbox": [ + 307, + 421, + 545, + 443 + ], + "type": "text", + "content": "[43] Daniel L Schacter and Donna Rose Addis. The ghosts of past and future. Nature, 445(7123):27-27, 2007. 2" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 445, + 545, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 445, + 545, + 521 + ], + "spans": [ + { + "bbox": [ + 307, + 445, + 545, + 521 + ], + "type": "text", + "content": "[44] Fadime Sener, Dipika Singhania, and Angela Yao. Temporal aggregate representations for long-range video understanding. In Andrea Vedaldi, Horst Bischof, Thomas Brox, and Jan-Michael Frahm, editors, Computer Vision - ECCV 2020 - 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XVI, volume 12361 of Lecture Notes in Computer Science, pages 154-171. Springer, 2020. 1, 7" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 522, + 545, + 599 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 522, + 545, + 599 + ], + "spans": [ + { + "bbox": [ + 307, + 522, + 545, + 599 + ], + "type": "text", + "content": "[45] Zheng Shou, Jonathan Chan, Alireza Zareian, Kazuyuki Miyazawa, and Shih-Fu Chang. CDC: convolutional-deconvolutional networks for precise temporal action localization in untrimmed videos. In 2017 IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2017, Honolulu, HI, USA, July 21-26, 2017, pages 1417-1426. IEEE Computer Society, 2017. 8" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 600, + 545, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 600, + 545, + 644 + ], + "spans": [ + { + "bbox": [ + 307, + 600, + 545, + 644 + ], + "type": "text", + "content": "[46] Bilge Soran, Ali Farhadi, and Linda Shapiro. Generating notifications for missing actions: Don't forget to turn the lights off! In Proceedings of the IEEE International Conference on Computer Vision, pages 4669-4677, 2015. 1" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 646, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 646, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 307, + 646, + 545, + 689 + ], + "type": "text", + "content": "[47] Zhan Tong, Yibing Song, Jue Wang, and Limin Wang. Videomae: Masked autoencoders are data-efficient learners for self-supervised video pre-training. CoRR, abs/2203.12602, 2022. 8" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 690, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 690, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 690, + 545, + 713 + ], + "type": "text", + "content": "[48] Hugo Touvron, Matthieu Cord, Matthijs Douze, Francisco Massa, Alexandre Sablayrolles, and Hervé Jégou. Training" + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "13834" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 714 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 67, + 72, + 287, + 138 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 287, + 138 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 287, + 138 + ], + "type": "text", + "content": "data-efficient image transformers & distillation through attention. In Marina Meila and Tong Zhang, editors, Proceedings of the 38th International Conference on Machine Learning, ICML 2021, 18-24 July 2021, Virtual Event, volume 139 of Proceedings of Machine Learning Research, pages 10347-10357. PMLR, 2021. 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 140, + 287, + 183 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 140, + 287, + 183 + ], + "spans": [ + { + "bbox": [ + 48, + 140, + 287, + 183 + ], + "type": "text", + "content": "[49] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Advances in neural information processing systems, 30, 2017. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 184, + 288, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 184, + 288, + 228 + ], + "spans": [ + { + "bbox": [ + 48, + 184, + 288, + 228 + ], + "type": "text", + "content": "[50] Limin Wang, Yuanjun Xiong, Zhe Wang, Yu Qiao, Dahua Lin, Xiaou Tang, and Luc Van Gool. Temporal segment networks: Towards good practices for deep action recognition. In ECCV, pages 20-36, 2016. 5" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 228, + 288, + 316 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 228, + 288, + 316 + ], + "spans": [ + { + "bbox": [ + 48, + 228, + 288, + 316 + ], + "type": "text", + "content": "[51] Pichao Wang, Xue Wang, Fan Wang, Ming Lin, Shuning Chang, Hao Li, and Rong Jin. KVT: k-nn attention for boosting vision transformers. In Shai Avidan, Gabriel J. Brostow, Moustapha Cisse, Giovanni Maria Farinella, and Tal Hassner, editors, Computer Vision - ECCV 2022: 17th European Conference, Tel Aviv, Israel, October 23-27, 2022, Proceedings, Part XXIV, volume 13684 of Lecture Notes in Computer Science, pages 285-302. Springer, 2022. 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 317, + 288, + 348 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 317, + 288, + 348 + ], + "spans": [ + { + "bbox": [ + 48, + 317, + 288, + 348 + ], + "type": "text", + "content": "[52] Sinong Wang, Belinda Z. Li, Madian Khabsa, Han Fang, and Hao Ma. Linformer: Self-attention with linear complexity. CoRR, abs/2006.04768, 2020. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 350, + 288, + 425 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 350, + 288, + 425 + ], + "spans": [ + { + "bbox": [ + 48, + 350, + 288, + 425 + ], + "type": "text", + "content": "[53] Wenhai Wang, Enze Xie, Xiang Li, Deng-Ping Fan, Kaitao Song, Ding Liang, Tong Lu, Ping Luo, and Ling Shao. Pyramid vision transformer: A versatile backbone for dense prediction without convolutions. In 2021 IEEE/CVF International Conference on Computer Vision, ICCV 2021, Montreal, QC, Canada, October 10-17, 2021, pages 548-558. IEEE, 2021. 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 426, + 287, + 469 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 426, + 287, + 469 + ], + "spans": [ + { + "bbox": [ + 48, + 426, + 287, + 469 + ], + "type": "text", + "content": "[54] Xiang Wang, Shiwei Zhang, Zhiwu Qing, Yuanjie Shao, Zhengrong Zuo, Changxin Gao, and Nong Sang. Long short-term transformer for online action detection. In ICCV, 2021. 2, 5, 7, 8" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 471, + 288, + 525 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 471, + 288, + 525 + ], + "spans": [ + { + "bbox": [ + 48, + 471, + 288, + 525 + ], + "type": "text", + "content": "[55] Yi Wang, Kunchang Li, Yizhuo Li, Yinan He, Bingkun Huang, Zhiyu Zhao, Hongjie Zhang, Jilan Xu, Yi Liu, Zun Wang, et al. Internvideo: General video foundation models via generative and discriminative learning. arXiv preprint arXiv:2212.03191, 2022. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 526, + 288, + 601 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 526, + 288, + 601 + ], + "spans": [ + { + "bbox": [ + 48, + 526, + 288, + 601 + ], + "type": "text", + "content": "[56] Chao-Yuan Wu, Yanghao Li, Karttikeya Mangalam, Haoqi Fan, Bo Xiong, Jitendra Malik, and Christoph Feichtenhofer. Memvit: Memory-augmented multiscale vision transformer for efficient long-term video recognition. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, CVPR 2022, New Orleans, LA, USA, June 18-24, 2022, pages 13577-13587. IEEE, 2022. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 603, + 288, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 603, + 288, + 645 + ], + "spans": [ + { + "bbox": [ + 48, + 603, + 288, + 645 + ], + "type": "text", + "content": "[57] Mingze Xu, Mingfei Gao, Yi-Ting Chen, Larry S Davis, and David J Crandall. Temporal recurrent networks for online action detection. In ICCV, pages 5532-5541, 2019. 2, 5, 7, 8" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 647, + 288, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 288, + 690 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 288, + 690 + ], + "type": "text", + "content": "[58] Mingze Xu, Yuanjun Xiong, Hao Chen, Xinyu Li, Wei Xia, Zhuowen Tu, and Stefano Soatto. Long short-term transformer for online action detection. In NeurIPS, 2021. 1, 2, 3, 5, 6, 7, 8" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 692, + 288, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 692, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 48, + 692, + 288, + 714 + ], + "type": "text", + "content": "[59] Xinyu Xu, Yong-Lu Li, and Cewu Lu. Learning to anticipate future with dynamic context removal. In Proceedings of" + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 498 + ], + "type": "list", + "angle": 0, + "index": 23, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "text", + "content": "the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12734-12744, 2022. 7" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 307, + 96, + 547, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 96, + 547, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 96, + 547, + 150 + ], + "type": "text", + "content": "[60] Antoine Yang, Antoine Miech, Josef Sivic, Ivan Laptev, and Cordelia Schmid. Tubedetr: Spatio-temporal video grounding with transformers. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 16442-16453, June 2022. 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 152, + 545, + 185 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 185 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 185 + ], + "type": "text", + "content": "[61] Le Yang, Junwei Han, and Dingwen Zhang. Colar: Effective and efficient online action detection by consulting exemplars. In CVPR, 2022. 2, 5, 8" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 186, + 545, + 240 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 186, + 545, + 240 + ], + "spans": [ + { + "bbox": [ + 307, + 186, + 545, + 240 + ], + "type": "text", + "content": "[62] Cunjun Yu, Xiao Ma, Jiawei Ren, Haiyu Zhao, and Shuai Yi. Spatio-temporal graph transformer networks for pedestrian trajectory prediction. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XII 16, pages 507-523. Springer, 2020. 1" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 241, + 545, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 241, + 545, + 274 + ], + "spans": [ + { + "bbox": [ + 307, + 241, + 545, + 274 + ], + "type": "text", + "content": "[63] Chen-Lin Zhang, Jianxin Wu, and Yin Li. Actionformer: Localizing moments of actions with transformers. CoRR, abs/2202.07925, 2022. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 275, + 545, + 340 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 275, + 545, + 340 + ], + "spans": [ + { + "bbox": [ + 308, + 275, + 545, + 340 + ], + "type": "text", + "content": "[64] Hongyi Zhang, Moustapha Cisse, Yann N. Dauphin, and David Lopez-Paz. mixup: Beyond empirical risk minimization. In 6th International Conference on Learning Representations, ICLR 2018, Vancouver, BC, Canada, April 30 - May 3, 2018, Conference Track Proceedings. OpenReview.net, 2018. 6" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 342, + 545, + 386 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 342, + 545, + 386 + ], + "spans": [ + { + "bbox": [ + 308, + 342, + 545, + 386 + ], + "type": "text", + "content": "[65] Yanyi Zhang, Xinyu Li, Chunhui Liu, Bing Shuai, Yi Zhu, Biagio Brattoli, Hao Chen, Ivan Marsic, and Joseph Tighe. Vidtr: Video transformer without convolutions. In ICCV, pages 13557-13567, 2021. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 387, + 545, + 419 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 387, + 545, + 419 + ], + "spans": [ + { + "bbox": [ + 308, + 387, + 545, + 419 + ], + "type": "text", + "content": "[66] Peisen Zhao, Jiajie Wang, Lingxi Xie, Ya Zhang, Yanfeng Wang, and Qi Tian. Privileged knowledge distillation for online action detection. CoRR, abs/2011.09158, 2020. 8" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 421, + 545, + 464 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 421, + 545, + 464 + ], + "spans": [ + { + "bbox": [ + 308, + 421, + 545, + 464 + ], + "type": "text", + "content": "[67] Yue Zhao and Philipp Krahenbuhl. Real-time online video detection with temporal smoothing transformers. In European Conference on Computer Vision (ECCV), 2022. 1, 2, 3, 5, 6, 7, 8" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 466, + 545, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 466, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 308, + 466, + 545, + 498 + ], + "type": "text", + "content": "[68] Yue Zhao, Ishan Misra, Philipp Krahenbuhl, and Rohit Girdhar. Learning video representations from large language models. CoRR, abs/2212.04501, 2022. 8" + } + ] + } + ], + "index": 22 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "13835" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 11 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/9db8fa07-a91f-4043-9a71-b3d3e6b17388_content_list.json b/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/9db8fa07-a91f-4043-9a71-b3d3e6b17388_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..6da972f27216a5612881d8cb88a5ff6052283407 --- /dev/null +++ b/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/9db8fa07-a91f-4043-9a71-b3d3e6b17388_content_list.json @@ -0,0 +1,1307 @@ +[ + { + "type": "text", + "text": "MemorySeg: Online LiDAR Semantic Segmentation with a Latent Memory", + "text_level": 1, + "bbox": [ + 104, + 130, + 864, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Enxu Li Sergio Casas Raquel Urtasun Waabi University of Toronto {tli, sergio, urtasun}@waabi.ai", + "bbox": [ + 307, + 181, + 665, + 234 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 268, + 313, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Semantic segmentation of LiDAR point clouds has been widely studied in recent years, with most existing methods focusing on tackling this task using a single scan of the environment. However, leveraging the temporal stream of observations can provide very rich contextual information on regions of the scene with poor visibility (e.g., occlusions) or sparse observations (e.g., at long range), and can help reduce redundant computation frame after frame. In this paper, we tackle the challenge of exploiting the information from the past frames to improve the predictions of the current frame in an online fashion. To address this challenge, we propose a novel framework for semantic segmentation of a temporal sequence of LiDAR point clouds that utilizes a memory network to store, update and retrieve past information. Our framework also includes a novel regularizer that penalizes prediction variations in the neighborhood of the point cloud. Prior works have attempted to incorporate memory in range view representations for semantic segmentation, but these methods fail to handle occlusions and the range view representation of the scene changes drastically as agents nearby move. Our proposed framework overcomes these limitations by building a sparse 3D latent representation of the surroundings. We evaluate our method on SemanticKITTI, nuScenes, and PandaSet. Our experiments demonstrate the effectiveness of the proposed framework compared to the state-of-the-art. For more information, visit the project website: https://waabi.ai/research/memoryseg.", + "bbox": [ + 75, + 301, + 473, + 724 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 753, + 209, + 768 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Semantic segmentation of LiDAR point clouds is a key component for the safe deployment of self-driving vehicles (SDV). It enables SDVs to enhance their understanding of the surrounding environment by categorizing every 3D point into specific classes of interest, such as vehicles, pedestrians, traffic signs, buildings, roadways, etc. This rich and precise 3D representation of the environment can then be used for various applications such as generating online or", + "bbox": [ + 75, + 779, + 468, + 902 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/5bb242696325f5413353a18ba9d10318de2d8beb984d13165a23469698b2feb8.jpg", + "image_caption": [ + "Figure 1. Objects could be partially occluded in single frame LiDAR point cloud. Our approach learns a 3D latent memory representation for better contextualizing the online observations. We apply PCA [14] to reduce the latent dimension to 3 and plot as RGB. (Best viewed in color and zoomed-in.)" + ], + "image_footnote": [], + "bbox": [ + 500, + 271, + 691, + 407 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/117f91f4cb516d038ac16fc603a00cf7e95bcd53d2648f90be1a404ab033d4e8.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 696, + 271, + 893, + 409 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "offline semantic maps, building localization priors, or making the shapes of an object tracker more precise.", + "bbox": [ + 498, + 500, + 890, + 532 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "LiDAR data is typically captured as a continuous stream of data, where every fraction of a second (typically 100ms) a new point cloud is available. Despite this fact, most LiDAR segmentation approaches process each frame independently [15, 32, 28, 22, 34, 5, 29] due to the computational and memory complexity associated with processing large amounts of 3D point cloud data. However, reasoning about a single frame suffers from the sparsity of the observations, particularly at range, and has difficulty handling occluded objects. Furthermore, the absence of motion information can make categorizing certain objects difficult.", + "bbox": [ + 496, + 534, + 892, + 700 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Several approaches [20, 19] utilize a sliding window approach, where a small set of past frames is processed independently at every time step. The main shortcoming of this approach is its limited temporal context (typically under 1 second) due to resource constraints, as processing multiple LiDAR scans at once is expensive. TemporalLidarSeg [8] proposed to utilize a latent spatial memory to retain information about the past while avoiding redundant computation every time a new scan is available, in a range view (RV) representation. However, the RV of the scene changes drastically as the SDV or the other actors move due to changes in perspective. As a result, the memory can be dominated by nearby objects, which appear larger in the RV representen", + "bbox": [ + 496, + 704, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "745", + "bbox": [ + 485, + 945, + 509, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "tation, making it challenging to be updated from frame to frame. Occlusion can be particularly challenging as the occluder now occupies the same spatial region that was previously describing the occluded object. This limits the usefulness of the memory. In contrast to RV, 3D is a metric space where the distances between points are preserved regardless of the viewpoint or relative distance to the SDV. Thus, representing the memory in 3D enables learning size priors for different classes. It allocates equal representation power to them regardless of the distance to the SDV, and enables easy understanding of motion. Moreover, previously observed regions that are currently occluded can be remembered in the memory as the occluder and occluded objects occupy different 3D regions, even though they share the same space in RV. Despite these advantages, 3D memory has been overlooked in LiDAR semantic segmentation.", + "bbox": [ + 80, + 90, + 467, + 332 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this paper we propose MEMORYSEG, a novel online LiDAR segmentation model that recurrently updates a sparse 3D latent memory as new observations are received, efficiently and effectively accumulating evidence from past observations. Fig. 1 illustrates the expressive power of such memory. In a single scan, objects are hard to identify due to sparsity (particularly at range) and lack of semantics, and occluded areas have no observations. In contrast, our latent memory is much denser, providing a rich context to separate different classes, especially in currently occluded regions.", + "bbox": [ + 80, + 335, + 467, + 486 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To achieve an effective memory update that takes into account both the past and the present for accurate decoding, our method addresses several challenges. First, we align the previous memory with the current observation in the latest ego frame, to compensate for the SDV motion. Second, the sparsity level of the memory and the observation embeddings are different, making fusion non-trivial. The latent memory is denser, and thus some currently unobserved locations may be present in the memory. Complementarily, some regions in the current scan have not been observed before, such as new observations appearing as the SDV drives further. For this reason, we propose a mechanism to fill in missing regions in the current observations and add new observations to the memory during the update. Third, other objects are also moving (potentially in opposite direction), thus fusing the memory and observation embeddings requires a large receptive field. We address this via a carefully designed architecture that achieves a large receptive field yet preserves sparsity for efficiency. Additionally, we introduce a novel point-level neighbourhood variation regularizer which penalizes significant differences in semantic predictions within local 3D neighborhoods.", + "bbox": [ + 80, + 489, + 467, + 820 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Extensive experiments in SemanticKITTI [2], nuScenes [4] and PandaSet [27] demonstrate that MEMORYSEG outperforms current state-of-the-art semantic segmentation methods that rely purely on LiDAR on multiple benchmarks.", + "bbox": [ + 80, + 824, + 467, + 898 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 504, + 90, + 638, + 104 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this section, we start by reviewing LiDAR semantic segmentation approaches in the literature and then focus on methods proposed for temporal LiDAR reasoning.", + "bbox": [ + 504, + 116, + 890, + 160 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. LiDAR Semantic Segmentation", + "text_level": 1, + "bbox": [ + 504, + 172, + 772, + 186 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "LiDAR-based semantic segmentation methods can be classified into four categories based on the type of data being processed: point-based [16, 17, 13, 24], projection-based [28, 7, 32], voxel-based [5, 34, 12], or a combination of the data representations [22, 29].", + "bbox": [ + 504, + 196, + 890, + 271 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Point-based approaches [16, 17, 13, 24] operate directly on the point cloud, but most [17, 13, 24] rely on down-sampling to accommodate limited computational resources. KPCov [24] introduces customized spatial kernel-based point convolution which yields the most favorable outcomes compared to other point-based methods. However, it requires a significant amount of computational resources, which can limit its practicality in certain applications.", + "bbox": [ + 504, + 272, + 890, + 393 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Projection-based methods [28, 7, 32] involve projecting a 3D point cloud onto a 2D image plane, which can be done using either in spherical Range-View [28, 7], BirdEye-View [32], or multi-view representations [11]. These approaches usually operate in real-time, benefiting from efficient 2D CNN inference on GPUs. However, they suffer from significant information loss due to projection, which can prevent them from being on par with state-of-the-art methods.", + "bbox": [ + 504, + 393, + 890, + 527 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The emergence of 3D voxel-based approaches [5, 34, 12] can be attributed to recent advancements in sparse 3D convolutions [6, 21]. Typically, LiDAR point clouds are converted into Cartesian [5] or Cylindrical [34] voxels and then processed using sparse convolutions. They have demonstrated state-of-the-art performance, but reducing voxel resolution can result in significant loss of information.", + "bbox": [ + 504, + 531, + 890, + 635 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Recently, researchers have explored the potential of leveraging multiple data representations [22, 30, 29, 31] to benefit from the information acquired by each representation. For instance, SPVNAS [22] incorporates both pointwise features and 3D-voxel features in their network while learning to segment. Similarly, RPVNet [29] utilizes a trilateral structure in their network, where each branch adopts a distinct data representation mentioned earlier.", + "bbox": [ + 504, + 637, + 890, + 757 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Our method takes a similar approach to incorporate both point and voxel representations in the network. Voxel representations are utilized for contextual information learning, while point representations are employed to preserve fine-grained details, such as object boundaries and curvatures.", + "bbox": [ + 504, + 758, + 890, + 833 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. Temporal LiDAR Reasoning", + "text_level": 1, + "bbox": [ + 504, + 845, + 753, + 861 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Previous methods [20, 19, 26] have attempted to integrate a small number of past frames to facilitate temporal", + "bbox": [ + 504, + 869, + 890, + 898 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "746", + "bbox": [ + 486, + 946, + 509, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "reasoning. For instance, SpSequenceNet [20] introduces cross-frame global attention, which uses information from the previous frame to emphasize features in the current frame. Additionally, it utilizes cross-frame local interpolation to combine local features from both the previous and current frame. Further, MetaRangeSeg [26] includes information from past frames by having the residual depth map as an additional feature to the input. However, these methods are not well-suited for continuous application to a temporal sequence of LiDAR point clouds. Firstly, they are inefficient as they discard previous observations and require the model to start from scratch each time a new point cloud is received. Secondly, they only aggregate temporal information within a short horizon, failing to capture the potential of temporal reasoning over a longer duration.", + "bbox": [ + 75, + 90, + 472, + 318 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Several works [8, 9] have attempted to incorporate temporal reasoning through a recurrent framework. Specifically, Duerr et al. [8] presents a recurrent segmentation architecture in RV, which uses previous observations as memory and aligns them temporally in the range image space. However, RV memory has limitations, such as prioritizing nearby objects, and suffering from contention of memory resources during occlusions (since information from behind the occluder and the occluder itself are now sharing the same memory entries). Further, StrObe [9] implemented a multi-scale 2D BEV memory for object detection enabling the network to take advantage of previous computations and process new LiDAR data incrementally. However, compared to object detection, semantic segmentation requires a more fine-grained and nuanced understanding of the scene and therefore a 3D memory is more suitable than 2D BEV.", + "bbox": [ + 75, + 321, + 472, + 565 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Our approach is distinct from previous methods as we propose an online LiDAR semantic segmentation framework utilizing a sparse 3D memory. By representing the memory in 3D, we preserve the distance between points regardless of viewpoint or distance from the SDV, allowing for size priors of different classes to be learned. Additionally, the memory also retains previously observed regions even when currently occluded, as occluders and occluded objects occupy different 3D regions, despite being in the same space in RV. Furthermore, we preserve fine-grained height details that are lost in the BEV memory.", + "bbox": [ + 75, + 569, + 472, + 737 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.3D Memory-based LiDAR Segmentation", + "text_level": 1, + "bbox": [ + 76, + 763, + 441, + 782 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this section we introduce MEMORYSEG, an online semantic segmentation framework for streaming LiDAR point clouds that leverages a 3D latent memory to remember the past and better handle occlusions and sparse observations. In the remainder of this section, we first describe our model formulation, then present the network architecture and finally explain the learning process.", + "bbox": [ + 75, + 794, + 470, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Model Formulation", + "text_level": 1, + "bbox": [ + 498, + 90, + 687, + 106 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Let $\\mathcal{P} = \\{\\mathcal{P}_t\\}_{t=1}^L$ be a sequence of LiDAR sweeps where $L \\in \\mathbb{N}^+$ is the sequence length and $t \\in [1, L]$ is the time index. Each LiDAR sweep $\\mathcal{P}_t = (\\mathbf{G}_t, \\mathbf{F}_t)$ is a $360^\\circ$ scan of the surrounding with $N_t$ unordered points. $\\mathbf{G}_t \\in \\mathbb{R}^{N_t \\times 3}$ contains the Cartesian coordinates in the ego vehicle frame and $\\mathbf{F}_t \\in \\mathbb{R}^{N_t}$ is the LiDAR intensity of the point. Let $\\mathbf{T}_{t-1 \\to t} \\in SE(3)$ be the pose transformation from the vehicle frame at time $t-1$ to $t$ .", + "bbox": [ + 496, + 112, + 890, + 233 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To make informed semantic predictions, in this paper we maintain a latent (or hidden) memory in 3D. This memory is sparse in nature since the majority of the 3D space is unoccupied. To represent this sparsity, we parametrize the memory at time $t$ using a sparse set of voxels containing the coordinates $H_{G,t} \\in \\mathbb{R}^{M_t \\times 3}$ and their corresponding learned embeddings $H_{F,t} \\in \\mathbb{R}^{M_t \\times d_m}$ . $M_t$ is the number of voxel entries in the latent memory at time $t$ and $d_m$ is the embedding dimension. Preserving the voxel coordinates is important to perform alignment as the reference changes when the SDV moves. We utilize a voxel-based sparse representation as it provides notable computational benefits with respect to dense tensors as well as sparse representations at the point level without sacrificing performance.", + "bbox": [ + 496, + 234, + 892, + 445 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Inference follows a three-step process that is repeated every time a new LiDAR sweep is available: (i) the encoder takes in the most recent LiDAR point cloud at current time $t$ and extracts point-level and voxel-level observation embeddings, (ii) the latent memory is updated taking into account the voxel-level embeddings from the new observations, and (iii) the semantic predictions are decoded by combining the point-level embeddings from the encoder and voxel-level embeddings from the updated memory. We refer the reader to Fig. 2 for an illustration of our method.", + "bbox": [ + 496, + 446, + 893, + 595 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The memory update stage faces challenges due to the changing reference frame as the SDV moves, different sparsity levels of memory and current LiDAR sweep, as well as the motion of other actors. To address these challenges, a Feature Alignment Module (FAM) is introduced to align the previous memory state with the current observation embeddings. Subsequently, an Adaptive Padding Module (APM) is utilized to fill in missing observations in the current data and add new observations to the memory. Then, a Memory Refinement Module (MRM) is employed to update the latent memory using padded observations. Next, we explain each component in more detail.", + "bbox": [ + 496, + 597, + 893, + 777 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Encoder: Following [22], our encoder is composed of a point-branch that computes point-level embeddings preserving the fine details and a voxel-branch that performs contextual reasoning through 3D sparse convolutional blocks [21]. The point-branch receives a 7-dimensional feature vector per point, with the xyz coordinates, intensity, and relative offsets to the nearest voxel center as features. It comprises two shared MLPs that output point embeddings,", + "bbox": [ + 496, + 779, + 893, + 902 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "747", + "bbox": [ + 485, + 944, + 509, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/dd010bd514f353a03c675e261fa2550d17534abb629a6c20ad5802aa64f0b154.jpg", + "image_caption": [ + "Figure 2. An overview of our model, MEMORYSEG. After the encoder processes the LiDAR point cloud at time $t$ , the resulting feature map is utilized to update the latent memory (see Fig. 3 for more details about the memory update). Then, the decoder combines the refined memory with the point embeddings from the encoder to obtain semantic predictions." + ], + "image_footnote": [], + "bbox": [ + 99, + 90, + 867, + 244 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/eb7a6e4abb0d0d94406f0da981144bf80ef8d0201ed05dc3925138e3d8049b63.jpg", + "image_caption": [ + "Figure 3. Overview of the latent memory update process. The latent memory embeddings $(H_{G,t - 1},H_{F,t - 1})$ are transformed to the ego frame at $t$ with the Feature Alignment Module (FAM). Next, the Adaptive Padding Module (APM) is utilized to learn the padding of both memory and observation embeddings. The Memory Refinement Module (MRM) updates the latent memory by incorporating the padded observation embeddings. The updated memory is then passed to the decoder for generating semantic predictions. (Best viewed in color and zoomed-in.)" + ], + "image_footnote": [], + "bbox": [ + 78, + 313, + 472, + 401 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "as illustrated in Fig. 2. We average point embeddings belonging to the same voxel from the first shared MLP over voxels of size $v_{b}$ to obtain voxel features. These features are then processed through four residual blocks with 3D sparse convolutions, each downsampling the feature map by a factor of 2. Two additional residual blocks with 3D sparse convolutions are applied to upsample the sparse feature maps. Unlike a full U-Net [18] that recovers features at the original resolution, we only upsample to $\\frac{1}{4}$ of the original size for computational efficiency reasons, and use the coarser features to update the latent memory before decoding finer details to output our semantic predictions.", + "bbox": [ + 75, + 546, + 468, + 728 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Feature Alignment: The reference frame changes as the SDV moves. We propose the Feature Alignment Module (FAM) to transform the latent memory from the ego frame at $t - 1$ to $t$ and align with the current observation embeddings. Specifically, we take the memory voxel coordinates $H_{G,t-1}$ and use the pose information $\\mathbf{T}_{t-1 \\to t}$ to project from the ego frame at $t - 1$ to $t$ . We then re-voxelize using the projected coordinates with a voxel size of $v_m$ . If multiple entries are inside the same memory voxel, we take the average of them to be the voxel feature. The resulting warped coordinates and embeddings of the memory in the", + "bbox": [ + 75, + 734, + 470, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "ego frame $t$ are denoted as $\\tilde{H}_{G,t}$ and $\\tilde{H}_{F,t}$ , respectively.", + "bbox": [ + 496, + 315, + 867, + 330 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Adaptive Padding: To handle the different sparsity of the latent memory and the voxel-level observation embeddings, we propose the Adaptive Padding Module (APM). We refer the readers to Fig. 3 for an illustration. First, we re-voxelize the encoder features with the same voxel size $v_{m}$ where entries within the same voxel are averaged. We denote the resulting coordinates and embeddings as $X_{G}$ and $X_{F}$ . Note that we omit $t$ in this section for brevity. Let $x_{G} \\subseteq X_{G}$ and $x_{F} \\subseteq X_{F}$ be the coordinates and embeddings of the new observations at time $t$ that are not present in the memory. To obtain an initial guess of the memory embedding for a new entry, we utilize a weighted aggregation approach within its surrounding neighbourhood. This involves taking into account the coordinate offsets relative to the existing neighbouring voxels in the memory, which provides insight into their importance for aggregation, similar to Continuous Conv [25]. In addition to this, we incorporate the feature similarities and feature distances as additional cues for the aggregation process. Encoding feature similarities is particularly useful for assigning weights to the neighborhood. In a dynamic scene with moving actors, the closest voxel may not always be the most important voxel. By providing feature similarities, the network can make more informed decisions. The goal of such completion is to make a hypothesis of the embedding at the previously unobserved location using the available information. More precisely, we add those entries in the memory where their coordinates are $h_{G}^{\\prime} = x_{G}$ and the embedding of each voxel $j$ are initialized as follows,", + "bbox": [ + 496, + 333, + 890, + 755 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nh _ {F, j} ^ {\\prime} = \\sum_ {i \\in \\Omega_ {\\tilde {H}} (j)} w _ {j i} \\tilde {H} _ {F, i}, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 611, + 767, + 890, + 801 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nw _ {j i} = \\psi \\left(\\tilde {H} _ {G, i} - x _ {G, j}, \\| \\tilde {H} _ {F, i} - x _ {F, j} \\|, \\frac {\\tilde {H} _ {F , i} \\cdot x _ {F , j}}{\\| \\tilde {H} _ {F , i} \\| \\| x _ {F , j} \\|}\\right), \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 506, + 821, + 890, + 859 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $i$ and $j$ are voxel indices, $\\Omega_{\\tilde{H}}(j)$ is the k-nearest-neighborhood of voxel $j$ in $\\tilde{H}_G$ , and $\\psi$ is a shared MLP", + "bbox": [ + 496, + 868, + 893, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "748", + "bbox": [ + 486, + 945, + 509, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "followed by a softmax layer on the dimension of neighbourhood to ensure $\\sum_{i}w_{ji} = 1$", + "bbox": [ + 75, + 90, + 468, + 121 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Second, we identify the regions in the memory that are unseen in the current observation and denote their coordinates and embeddings as $\\tilde{h}_G \\subseteq \\tilde{H}_G$ and $\\tilde{h}_F \\subseteq \\tilde{H}_F$ . We add entries $x_G'$ and $x_F'$ to complete the current observation in a similar manner.", + "bbox": [ + 75, + 121, + 468, + 196 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Memory Refinement: We design a sparse version of a ConvGRU [1] to update the latent memory $H_{F,t-1}^{\\prime}$ using the current padded observation embeddings $X_{F,t}^{\\prime}$ as follows:", + "bbox": [ + 76, + 199, + 468, + 246 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} r _ {t} = \\operatorname {s i g m o i d} \\left[ \\Psi_ {r} \\left(X _ {F, t} ^ {\\prime}, H _ {F, t - 1} ^ {\\prime}\\right) \\right], \\\\ z _ {t} = \\operatorname {s i g m o i d} \\left[ \\Psi_ {z} \\left(X _ {F, t} ^ {\\prime}, H _ {F, t - 1} ^ {\\prime}\\right) \\right], \\\\ \\hat {H} _ {F, t} = \\tanh \\left[ \\Psi_ {u} \\left(X _ {F, t} ^ {\\prime}, r _ {t} \\cdot H _ {F, t - 1} ^ {\\prime}\\right) \\right], \\tag {3} \\\\ H _ {F, t} = \\hat {H} _ {F, t} \\cdot z _ {t} + H _ {F, t - 1} ^ {\\prime} \\cdot (1 - z _ {t}), \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 148, + 258, + 468, + 340 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\Psi_r, \\Psi_z, \\Psi_u$ are sparse 3D convolutional blocks with downsampling layers that aim to expand the receptive field and upsampling layers that restore the embeddings to their original size. $r_t$ and $z_t$ are learned signals to reset or update the memory, respectively. We refer the readers to the supplementary material about the detailed architecture of the sparse convolutional blocks.", + "bbox": [ + 75, + 351, + 468, + 455 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Decoder: Our decoder consists of an MLP, two residual blocks with sparse 3D convolutions, and a linear semantic header. Specifically, we first take the corresponding memory embeddings at coordinates $\\mathbf{G}_t$ and add with the point embeddings from the encoder. The resulting combined embeddings are then voxelized with voxel size of $\\frac{v_b}{4}$ and further processed by two residual blocks that upsample the feature maps back to the original resolution. In parallel, an MLP takes the point embeddings before voxelization to retain the fine-grained details. Finally, the semantic header takes the combination of voxel and point embeddings to obtain per-point semantic predictions.", + "bbox": [ + 75, + 459, + 468, + 641 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Memory Initialization: At the start of the sequence ( $t = 0$ ), the first observation is used to initialize memory, with $H_{G,0} = X_{G,0}$ and $H_{F,0} = X_{F,0}$ .", + "bbox": [ + 76, + 643, + 468, + 689 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.2. Learning", + "text_level": 1, + "bbox": [ + 76, + 699, + 184, + 714 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We learn our segmentation model by minimizing a linear combination of conventional segmentation loss functions [13, 34, 22] and a novel point-wise regularizer to better supervise the network training.", + "bbox": [ + 75, + 722, + 468, + 782 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nJ = \\beta_ {w c e} J _ {w c e} + \\beta_ {l s} J _ {l s} + \\beta_ {r e g} J _ {r e g}. \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 151, + 796, + 468, + 813 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Here, $J_{wce}$ denotes cross-entropy loss, weighted by the inverse frequency of classes, to address class imbalance in the dataset. The Lovasz Softmax Loss ( $J_{ls}$ ) [3] is used to train the network, as it is a differentiable surrogate for the non-convex intersection over union (IoU) metric, which is", + "bbox": [ + 75, + 824, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "a commonly used evaluation metric for semantic segmentation. Additionally, $J_{reg}$ corresponds to our proposed pointwise regularizer. $\\beta_{reg}, \\beta_{wce}$ and $\\beta_{ls}$ are hyperparameters.", + "bbox": [ + 498, + 90, + 890, + 137 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Point-wise Smoothness: Our regularizer is designed to limit significant variations in semantic predictions within the 3D neighborhood of each point, except when these variations occur at the class boundary. Formally,", + "bbox": [ + 498, + 138, + 890, + 200 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} J _ {r e g} = \\frac {1}{N _ {t}} \\sum_ {\\substack {i = 1 \\\\ 1}} ^ {N _ {t}} | \\Delta (Y, i) - \\Delta (\\hat {Y}, i) |, \\tag{5} \\\\ \\Delta (Y, i) = \\Big | \\frac {1}{| \\Omega_ {\\mathcal {P} _ {t}} (i) |} \\sum_ {j \\in \\Omega_ {\\mathcal {P} _ {t}} (i)} | y _ {i} - y _ {j} | \\Big |. \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 566, + 214, + 890, + 295 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Here, $\\Delta(Y, i)$ represents the ground truth semantic variation around point $i$ , while $\\Delta(\\hat{Y}, i)$ corresponds to the predicted semantic variation around point $i$ . We use $\\hat{Y} \\in \\mathbb{R}^{N_t \\times C}$ to denote the predicted semantic distribution over $C$ classes, and $Y \\in \\mathbb{R}^{N_t \\times C}$ to denote the ground truth semantic one-hot label. The variable $y_i$ represents the $i$ -th element of $Y$ . $\\Omega_{\\mathcal{P}_t}(i)$ denotes the neighborhood of point $i$ in $\\mathcal{P}_t$ , and $|\\Omega_{\\mathcal{P}_t}(i)|$ represents the number of points in the neighborhood. The inspiration for this regularizer comes from a study by [11] that penalizes adjacent pixel prediction variations with the ground truth.", + "bbox": [ + 498, + 309, + 890, + 476 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 500, + 493, + 632, + 508 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In this section, we thoroughly analyze the performance of our method on three different datasets: SemanticKITTI [2], nuScenes [4], and PandaSet [27]. These datasets were collected using different LiDAR sensors and in diverse geographical regions. Our results demonstrate that MEMORY-SEG outperforms the current state of the art in all benchmarks. Additionally, we conduct ablation studies to understand the impact of our contributions. We demonstrate that incorporating a 3D sparse latent memory improves semantic predictions, with a very significant gain in long-range areas as these are sparser and more often partially obstructed than short-range regions.", + "bbox": [ + 498, + 518, + 890, + 700 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Datasets: We benchmark our approach on three large-scale autonomous driving datasets: SemanticKITTI [2] consists of 22 sequences from the KITTI Odometry Dataset [10], which was collected in Germany using a Velodyne HDL-64E LiDAR. We use the standard split where sequences 0 to 10 are used for training (with sequence 8 for validation), and sequences 11 to 21 are held for testing. We follow the standard setting where semantic labels are mapped to 19 classes for the single-scan benchmark and 25 for the multi-scan benchmark. In the latter, all movable classes are further divided into moving and non-moving classes. Given that prior research on temporal aggregation for semantic segmentation is more prevalent in", + "bbox": [ + 496, + 703, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "749", + "bbox": [ + 485, + 945, + 509, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/62f97c9815d0000fa18ca0e2f10e77a1d9534031784def7f62be593c95e85616.jpg", + "table_caption": [], + "table_footnote": [ + "Table 1. Comparison to the state-of-the-art methods on the test set of SemanticKITTI [2] multi-scan benchmark. (m) indicates moving. We include LiDAR-only published approaches at the time of submission. These approaches are categorized into two groups: the first group includes methods that aim for single-scan segmentation but use multiple aggregated frames as input; the second group consists of methods that introduce temporal aggregation modules explicitly tailored for handling multiple scans. Metrics are provided in [%]." + ], + "table_body": "
MethodmIoUCarBicycleMoonecycleTruckOther VehiclePersonBicyclistMoonecyclistRoadParkingSidewalkOther GroundBuildingFenceVegetationTrunkTerrainPoleTraffic Signcar (m)bicyclist (m)person (m)motorcycle (m)other-vehicle (m)truck (m)
TangentConv [23]34.184.92.018.221.118.51.60.00.083.938.364.015.385.849.179.543.256.736.431.240.31.16.41.930.142.2
DarkNet53Seg [2]41.684.130.432.920.220.77.50.00.091.664.975.327.585.256.578.450.764.838.153.361.514.115.20.228.937.8
KPConv [24]51.293.744.947.242.538.621.60.00.086.558.470.526.790.864.584.670.366.057.053.969.467.467.547.24.75.8
Cylinder3D [34]52.594.667.663.841.338.812.51.70.290.765.074.532.392.666.085.872.068.963.161.474.968.365.711.90.10.0
SpSequenceNet [20]43.188.524.026.229.222.76.30.00.090.157.673.927.191.266.884.066.065.750.848.753.241.226.236.22.30.1
TemporalLidarSeg [8]47.092.147.740.939.235.014.40.00.091.859.675.823.289.863.882.362.564.752.660.468.242.840.412.912.42.1
TemporalLatticeNet [19]47.191.635.436.126.923.09.40.00.091.559.375.327.589.665.384.666.770.457.260.459.741.751.048.85.90.0
Meta-RangeSeg [26]49.790.850.049.529.534.816.60.00.090.862.974.826.589.862.182.865.766.556.264.569.060.457.922.016.62.6
MEMORYSEG [ours]58.394.068.368.851.340.927.00.32.889.964.374.829.292.269.384.875.170.165.568.571.774.471.773.915.113.6
", + "bbox": [ + 80, + 88, + 888, + 210 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "the multi-scan benchmark, we consider it more appropriate for evaluating our proposed method. Single-scan benchmark results are also provided in the supplementary material. nuScenes [4] was collected in Boston and Singapore using a Velodyne HDL-32E LiDAR sensor, which captures sparser point clouds that pose extra challenges for semantic reasoning. The dataset contains a total of 1000 scenes, with 700 scenes used for training, 150 for validation, and the remaining 150 held out for testing. Each scene contains about 40 labeled frames recorded at $2\\mathrm{Hz}$ . We follow the standard setting which maps 31 fine-grained classes to 16 classes for training and evaluation. PandaSet [27] provides short sequences of temporal data but with a large number of moving actors in Silicon Valley. This dataset was collected using a Hesai-Pandar64 LiDAR and consists of 103 sequences, each with a length of 8 seconds. Following [8], we grouped the original fine-grained semantic classes into 14 for training and testing, trying to match the classes in other popular segmentation benchmarks [2, 4]. We also used the same train/Validation/test split as in the reference paper.", + "bbox": [ + 80, + 279, + 467, + 580 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Implementation details: For all datasets, we first train the network without the memory update for single-scan segmentation for 50 epochs. Then, we freeze the encoder and train the memory update block and decoder in a recurrent fashion for an additional 20 epochs. During each training iteration, we use the first 10 consecutive sweeps as warmup memory, and then train the network with backpropagation through time (BPTT) on the next 3 frames. The memory voxel size $v_{m}$ is $0.5\\mathrm{m}$ , and the embedding dimension $d_{m}$ is 128. We use the AdamW optimizer with a starting learning rate of 0.003 and a decay factor of 0.9. During training, we use data augmentation including global scaling sampled at random from [0.80, 1.20], translation sampled from [0, 0.2] m on all three axes, and global rotation around the Z axis with a random angle sampled from $[-\\pi ,\\pi ]$ . We set the loss weights $\\beta_{wce}$ to 1, $\\beta_{ls}$ to 2, and $\\beta_{reg}$ to 500. We set the regularizer neighborhood $\\Omega_{P_t}(i)$ to be the closest 32 points around point $i$ , and use a padding neighbourhood $\\Omega_{\\tilde{H}}(j)$ to be the closest 5 voxels of voxel $j$ . All experiments are conducted using 4 NVIDIA T4 GPUs with a batch size of 1 per GPU. During evaluation, we unroll each sequence from the", + "bbox": [ + 80, + 584, + 467, + 898 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "first frame to the end and follow [34, 12] to apply test-time-augmentation, i.e. averaging prediction scores of 10 forward passes with augmented input from a single model.", + "bbox": [ + 503, + 279, + 890, + 323 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To adapt to the uniqueness of each dataset, we consider the following per-dataset settings. To train on the SemanticKITTI dataset, we set the voxel size $v_{b}$ to 0.05 m. Due to the limited quantities of movable actors in this dataset, following [33] we generate a library of instances from the training sequences and randomly inject 5 objects over the ground classes at each frame during training. To improve the ability to separate classes into moving and non-moving actors, we add another linear header to classify points as moving or static and fuse the results from the semantic header. More implementation details are provided in the supplementary material. For nuScenes, the voxel size is set to 0.1 m, and 0.125 m for PandaSet.", + "bbox": [ + 503, + 325, + 890, + 518 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Metrics: We follow existing works [34, 5, 29] and use the intersection over union (IoU) averaged over all classes as the main metric (mIoU). Class-wise IoUs are also reported. Comparison against state-of-the-art: Our results are compared with other state-of-the-art approaches on the test set of three datasets in Tab. 1 to 3. We include approaches that use LiDAR only for fair comparison. Notably, our proposed method outperforms all prior works on all three datasets, demonstrating its generalizability across various LiDAR sensors and different geographical regions.", + "bbox": [ + 503, + 522, + 890, + 672 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Tab. 1 presents a comparison of our approach on the SemanticKITTI multi-scan benchmark, which is designed to evaluate methods that focus on temporal aggregation for semantic segmentation. The other methods in the table are divided into two groups. The first group consists of baselines that are designed for single-scan segmentation but aggregate multiple consecutive frames as input at the cost of higher memory consumption and longer runtime. In contrast, the second group proposes temporal aggregation modules specifically to handle multiple scans. It is worth noting that our proposed method performs significantly better than all of these approaches. MEMORYSEG demonstrates exceptional performance in segmenting dynamic actors, such as moving bicyclist, motorcyclist, and person. These substantial improvements can be attributed to the proposed re", + "bbox": [ + 503, + 675, + 890, + 898 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "750", + "bbox": [ + 486, + 946, + 509, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/e8ba7269a459b7f2f6a7b35233e17fcc9812e455be0b96ff59c317fac47833a1.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodmIoUFW-mIoUBarrierBicycleBusCarConstructionMotorcyclePedestrainTraffic ConeTrailerTruckDrivableOther FlatSidewalkTerrainMannmadeVegetation
PolarNet [32]69.487.472.216.877.086.551.169.764.854.169.763.596.667.177.772.187.184.5
Cylinder3D [34]77.289.982.829.884.389.463.079.377.273.484.669.197.770.280.375.590.487.6
SPVCNN [22]77.489.780.030.091.990.864.779.075.670.981.074.697.469.280.076.189.387.1
(AF)2-S3Net [5]78.388.578.952.289.984.277.474.377.372.083.973.897.166.577.574.087.786.8
MEMORYSEG [ours]80.691.484.940.291.292.471.273.585.977.888.076.497.969.081.277.692.689.7
", + "bbox": [ + 81, + 88, + 888, + 196 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/6111709c4eed82f35fbc00dab61043a0841f87ba0094eaeae26fac40d42846c9.jpg", + "table_caption": [ + "Table 2. Comparison to the state-of-the-art methods on the test set of nuScenes [4] LiDAR semantic segmentation benchmark. We include LiDAR-only published approaches at the time of submission. Metrics are provided in [%]" + ], + "table_footnote": [], + "table_body": "
MethodmIoUCarBicycleMotorcycleTruckOther VehiclePersonRoadRoad BarriersSidewalkBuildingVegetationTerrainBackgroundTraffic Sign
SqueezeSegv3 [28]55.792.824.118.036.554.363.091.111.971.386.285.061.363.220.6
SalsaNext [7]57.892.140.731.728.756.269.090.022.667.185.683.458.563.320.6
TemporalLidarSeg [8]60.093.733.638.037.159.972.091.114.670.688.288.463.868.420.7
SPVCNN [22]64.795.838.146.344.074.178.691.228.370.387.287.561.567.535.6
MEMORYSEG [ours]70.397.260.258.462.974.382.692.127.774.189.490.764.972.836.4
", + "bbox": [ + 160, + 234, + 807, + 340 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 3. Comparison to the state-of-the-art methods on the test set of PandaSet [27]. Metrics are provided in [%].", + "bbox": [ + 150, + 340, + 813, + 353 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "current framework, which implicitly encode the motion of moving actors in the 3D latent memory. Furthermore, we also demonstrate the effectiveness of our approach on the single-scan benchmark of the same dataset. We refer the readers to the supplementary material for the detailed results. This is a more competitive benchmark focusing on single-scan semantic segmentation where previous research has focused on proposing various architectures [5, 29, 34] or knowledge distillation techniques [12]. Our results show that MEMORYSEG can outperform these methods, which are highly optimized for this benchmark.", + "bbox": [ + 80, + 366, + 467, + 531 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Results on nuScenes [4] benchmark are presented in Tab. 2. MEMORYSEG outperforms the previous state-of-the-art. Our method is particularly effective in smaller classes such as barriers, pedestrians, and traffic cones, which present challenges for semantic segmentation networks due to the sparser point clouds available in this dataset. However, our approach overcomes this limitation by using a 3D latent memory to improve semantic reasoning of the sparse points. Additionally, we observe significant gains in the background classes, such as sidewalk, terrain, and manmade, which often rely on understanding of the surrounding to be segmented correctly. Our method improves the contextual reasoning by accumulating past observations using a latent memory representation.", + "bbox": [ + 80, + 535, + 467, + 746 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Finally, we compare our results with the state-of-the-art methods on PandaSet [27] and report the test set IoUs in Tab. 3. Our proposed method also achieves state-of-the-art performance in this dataset. Notably, our approach outperforms others by a large margin in almost all classes. We highlight that MEMORYSEG consistently outperforms TemporalLidarSeg [8] across multiple benchmarks, a method that also proposes a latent memory but in RV instead of 3D. These findings confirm our hypothesis that the 3D latent memory approach is more effective than using RV in", + "bbox": [ + 80, + 750, + 467, + 900 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "accurately segmenting objects in 3D point clouds.", + "bbox": [ + 503, + 366, + 826, + 381 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Importance of the memory: Fig. 4 highlights the significance of incorporating memory, particularly in longer range regions where point clouds are much sparser. To assess the effectiveness of the learned latent memory, we compare against our encoder and decoder without the memory update module as the single frame baseline (SFB). Our proposed network consistently outperforms the SFB in all regions, with the most significant improvement observed in the long-range region of nuScenes, where points are sparser and more difficult to contextualize. Thanks to the 3D sparse latent memory that accumulates semantic embeddings of past frames, our proposed approach performs much better than the SFB, particularly in those challenging regions. Fig. 5 provides similar insights. In the top-left of the figure, the SFB fails to segment a partially occluded vehicle located behind a fence. In contrast, our proposed approach initially segments the vehicle as other vehicle class, but as the ego vehicle advances, the 3D latent memory accumulates and refines through new observations, enabling the network to correctly identify the vehicle as a car after two sweeps. This illustration further confirms that the proposed 3D latent memory provides better contextualization of sparse objects that are partially occluded. Additional qualitative results are provided in the supplementary materials. We also quantitatively demonstrate the importance of memory in Tab. 4. M1 builds on SFB and incorporates FAM and MRM. Note that both FAM and MRM are essential for updating the latent memory continuously. FAM aligns the sparse 3D latent memory in the traveling ego frame, while MRM helps in learning to reset and update the memory recurrently. APM is replaced with zero-padding in M1 to highlight the significance of memory. M1 shows a $2.3\\%$ improvement in the mIoU metric compared to SFB, attributed to the ability of the sparse 3D latent memory to aggregate information in the", + "bbox": [ + 501, + 387, + 888, + 898 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "751", + "bbox": [ + 486, + 946, + 508, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c348a92562f83dc6f81a722b53334aa51d91ac4d8133d3b32cbc9ff1f36538cf.jpg", + "image_caption": [ + "Figure 4. Comparison of MEMORYSEG with single frame baseline (SFB) on the validation set with different distance-range." + ], + "image_footnote": [], + "bbox": [ + 86, + 90, + 225, + 181 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/16a254d4d06ebc9e4d62b15bcb503d1ffa68b8f04d1226febbd8f6da7be64b03.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 227, + 90, + 323, + 181 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/a9b38dbbd4ac12da2f32f0361b8bf1bc03c879777c81cefdd4f2d2537f42021d.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 323, + 90, + 459, + 181 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/c36b96394e07a95ad5a8dc2679eb6408d10ed23e71334877732f3c8e4fe54fd7.jpg", + "image_caption": [ + "Figure 5. Predictions of MEMORYSEG over time are illustrated in the bottom row. We include the prediction from the single frame baseline (SFB) and ground truth with color code at the top." + ], + "image_footnote": [], + "bbox": [ + 81, + 220, + 467, + 388 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "temporal dimension as the ego moves through the scene.", + "bbox": [ + 76, + 465, + 449, + 481 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Influence of adaptive padding: In this section, we compare our proposed APM with zero padding and Continuous Conv [25]. The results are presented in Tab. 4. M2 is an extension of M1 that introduces adaptive padding on both observation and memory embeddings when they are aligned. However, the padded entries are only processed using the relative coordinates in the neighborhood, similar to Continuous Conv [25] with the attention mechanism. A slight improvement of $0.2\\%$ is observed when new observations in the latent memory are initialized with a learned guess instead of all zeros. To further improve the performance of the network, M4 exploits feature similarities and distances in APM. When assigning an initial embedding to a new entry, both the relative position and the similarity to neighbors are considered. This is particularly useful for moving actors in the scene, where the network should learn to start with a guess with a similar embedding in the neighborhood, rather than the closest entry. By comparing M0 with M3 further confirms the usefulness of the proposed APM.", + "bbox": [ + 75, + 486, + 468, + 773 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Influence of memory refinement: In M3 of Tab. 4, we replace our proposed MRM with a vanilla sparse ConvGRU [1], which has a limited receptive field due to the convolution kernel size, making it challenging for fast-moving actors. However, MRM overcomes this limitation by down-sampling features to increase the receptive field. This improves the learning of meaningful reset and update gates for refining the latent memory.", + "bbox": [ + 75, + 779, + 467, + 900 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/bfe8fa4fe7101edbdd298074a4c3da923108eb77d02dc92672762282aa0a42de.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
FAMAPMMRMmIoU
CCOursSCGOurs
SFB67.2
M0✓✓✓68.9
M1✓✓69.5
M2✓✓✓69.7
M3✓✓✓69.7
M4✓✓✓70.8
", + "bbox": [ + 516, + 88, + 877, + 198 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/70a5c83324a4c2969d722ae9f5bab487551481b00150b5939b114caaf40204e5.jpg", + "table_caption": [ + "Table 4. Ablation on the proposed components in the network. Metrics are mIoU on the validation set of SemanticKITTI [2] provided in [%]. FAM: Feature Alignment Module, APM: Adaptive Padding Module, CC: padding using Continuous Conv [25], SCG: Sparse ConvGRU [1]. MRM: Memory Refinement Module." + ], + "table_footnote": [], + "table_body": "
RegularizerSemanticKITTInuScenesPandaSet
66.472.964.7
✓67.276.766.6
", + "bbox": [ + 532, + 280, + 859, + 323 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 5. Ablation on the model performance with and without the proposed regularizer. Metrics are mIoU on the validation set provided in [%].", + "bbox": [ + 498, + 333, + 890, + 375 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Influence of the regularizer: To demonstrate the effectiveness of our regularizer to train semantic segmentation networks on point clouds with different characteristics, we ablate this loss on the three datasets and summarize the results in Tab. 5. The results consistently show that incorporating the regularizer leads to performance improvements. The regularizer provides additional supervision on variations and boundaries, which is particularly beneficial for nuScenes. We note once again that this dataset has sparser point clouds than the other two.", + "bbox": [ + 496, + 388, + 890, + 537 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Parameter count and runtime comparison: MEMORY-SEG incurs only a relatively small computational overhead of $23\\%$ more parameters and $20\\%$ runtime than SFB. On the other hand, when naively concatenating the past five frames as the input to the model, despite having the same number of parameters as SFB, it takes 1.58 times longer (32% slower than our method) while only exploiting a limited 0.5-second window from the past.", + "bbox": [ + 496, + 542, + 890, + 662 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 678, + 617, + 693 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this paper, we have proposed a novel online LiDAR segmentation model named MEMORYSEG, which utilizes a sparse 3D latent memory to recurrently accumulate learned semantic embeddings from past observations. We also presented a novel variation regularizer to supervise the learning of 3D semantic segmentation on point clouds. Our results demonstrate that our approach achieve state-of-the-art performance on three large-scale datasets. This improved performance can be attributed to the ability of the latent memory to better contextualize objects in the scene. Looking ahead, our future work will focus on integrating instance segmentation and tracking to develop an end-to-end memory-augmented panoptic segmentation framework.", + "bbox": [ + 496, + 704, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "752", + "bbox": [ + 485, + 945, + 509, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Nicolas Ballas, Li Yao, Chris Pal, and Aaron C. Courville. Delving deeper into convolutional networks for learning video representations. In 4th International Conference on Learning Representations, ICLR 2016, San Juan, Puerto Rico, May 2-4, 2016, Conference Track Proceedings, 2016.", + "[2] Jens Behley, Martin Garbade, Andres Milioto, Jan Quenzel, Sven Behnke, Cyril Stachniss, and Jürgen Gall. Semantickitti: A dataset for semantic scene understanding of lidar sequences. In 2019 IEEE/CVF International Conference on Computer Vision, pages 9296-9306. IEEE, 2019.", + "[3] Maxim Berman, Amal Rannen Triki, and Matthew B Blaschko. The lovasz-softmax loss: A tractable surrogate for the optimization of the intersection-over-union measure in neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4413-4421, 2018.", + "[4] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11621-11631, 2020.", + "[5] Ran Cheng, Ryan Razani, Ehsan Taghavi, Enxu Li, and Bingbing Liu. af2-s3net: Attentive feature fusion with adaptive feature selection for sparse semantic segmentation network. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 12547-12556, 2021.", + "[6] Christopher Choy, JunYoung Gwak, and Silvio Savarese. 4d spatio-temporal convnets: Minkowski convolutional neural networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 3075-3084, 2019.", + "[7] Tiago Cortinhal, George Tzelepis, and Eren Erdal Aksoy. Salsanext: Fast semantic segmentation of lidar point clouds for autonomous driving. In 2020 IEEE Intelligent Vehicles Symposium (IV), pages 655-661, 2020.", + "[8] Fabian Duerr, Mario Pfaller, Hendrik Weigel, and Jürgen Beyerer. Lidar-based recurrent 3d semantic segmentation with temporal memory alignment. In 2020 International Conference on 3D Vision (3DV), pages 781-790. IEEE, 2020.", + "[9] Davi Frossard, Shun Da Suo, Sergio Casas, James Tu, and Raquel Urtasun. Strobe: Streaming object detection from lidar packets. In Jens Kober, Fabio Ramos, and Claire Tomlin, editors, Proceedings of the 2020 Conference on Robot Learning, volume 155 of Proceedings of Machine Learning Research, pages 1174-1183. PMLR, 16-18 Nov 2021.", + "[10] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the kitti vision benchmark suite. In Conference on Computer Vision and Pattern Recognition (CVPR), 2012.", + "[11] Martin Gerdzhev, Ryan Razani, Ehsan Taghavi, and Liu Bingbing. Tornado-net: multiview total variation semantic segmentation with diamond inception module. In 2021" + ], + "bbox": [ + 78, + 114, + 470, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "IEEE International Conference on Robotics and Automation (ICRA), pages 9543-9549, 2021.", + "[12] Yuenan Hou, Xinge Zhu, Yuexin Ma, Chen Change Loy, and Yikang Li. Point-to-voxel knowledge distillation for lidar semantic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8479-8488, 2022.", + "[13] Qingyong Hu, Bo Yang, Linhai Xie, Stefano Rosa, Yulan Guo, Zhihua Wang, Niki Trigoni, and Andrew Markham. Randla-net: Efficient semantic segmentation of large-scale point clouds. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 11108-11117, 2020.", + "[14] Ian Jolliffe. *Principal Component Analysis*. John Wiley & Sons, Ltd, 2005.", + "[15] Andres Milioto, Ignacio Vizzo, Jens Behley, and Cyril Stachniss. Rangenet++: Fast and accurate lidar semantic segmentation. In Proc. of the IEEE/RSJ Intl. Conf. on Intelligent Robots and Systems (IROS), 2019.", + "[16] Charles R Qi, Hao Su, Kaichun Mo, and Leonidas J Guibas. Pointnet: Deep learning on point sets for 3d classification and segmentation. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 652-660, 2017.", + "[17] Charles Ruizhongtai Qi, Li Yi, Hao Su, and Leonidas J Guibas. Pointnet++: Deep hierarchical feature learning on point sets in a metric space. Advances in neural information processing systems, 30, 2017.", + "[18] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In Medical Image Computing and Computer-Assisted Intervention-MICCAI 2015: 18th International Conference, Munich, Germany, October 5-9, 2015, Proceedings, Part III 18, pages 234-241. Springer, 2015.", + "[19] Peer Schütt, Radu Alexandru Rosu, and Sven Behnke. Abstract flow for temporal semantic segmentation on the permutohedral lattice. In Proceedings of the IEEE International Conference on Robotics and Automation (ICRA), 2022.", + "[20] Hanyu Shi, Guosheng Lin, Hao Wang, Tzu-Yi Hung, and Zhenhua Wang. Spsequencenet: Semantic segmentation network on 4d point clouds. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 4574-4583, 2020.", + "[21] Haotian Tang, Zhijian Liu, Xiuyu Li, Yujun Lin, and Song Han. Torchsparse: Efficient point cloud inference engine. Proceedings of Machine Learning and Systems, 4:302-315, 2022.", + "[22] Haotian Tang, Zhijian Liu, Shengyu Zhao, Yujun Lin, Ji Lin, Hanrui Wang, and Song Han. Searching efficient 3d architectures with sparse point-voxel convolution. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23–28, 2020, Proceedings, Part XXVIII, pages 685–702. Springer, 2020.", + "[23] Maxim Tatarchenko, Jaesik Park, Vladlen Koltun, and Qian-Yi Zhou. Tangent convolutions for dense prediction in 3d. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3887-3896, 2018.", + "[24] Hugues Thomas, Charles R Qi, Jean-Emmanuel Deschaud, Beatrix Marcotegui, François Goulette, and Leonidas J" + ], + "bbox": [ + 503, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "753", + "bbox": [ + 486, + 945, + 509, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Guibas. Kpconv: Flexible and deformable convolution for point clouds. In Proc. of the IEEE International Conference on Computer Vision, pages 6411-6420, 2019.", + "[25] Shenlong Wang, Simon Suo, Wei-Chiu Ma, Andrei Pokrovsky, and Raquel Urtasun. Deep parametric continuous convolutional neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2589-2597, 2018.", + "[26] Song Wang, Jianke Zhu, and Ruixiang Zhang. Metarangeseg: Lidar sequence semantic segmentation using multiple feature aggregation. IEEE Robotics and Automation Letters, 7(4):9739-9746, 2022.", + "[27] Pengchuan Xiao, Zhenlei Shao, Steven Hao, Zishuo Zhang, Xiaolin Chai, Judy Jiao, Zesong Li, Jian Wu, Kai Sun, Kun Jiang, et al. Pandaset: Advanced sensor suite dataset for autonomous driving. In 2021 IEEE International Intelligent Transportation Systems Conference (ITSC), pages 3095-3101. IEEE, 2021.", + "[28] Chenfeng Xu, Bichen Wu, Zining Wang, Wei Zhan, Peter Vajda, Kurt Keutzer, and Masayoshi Tomizuka. Squeeze-segv3: Spatially-adaptive convolution for efficient pointcloud segmentation. In European Conference on Computer Vision, pages 1-19. Springer, 2020.", + "[29] Jianyun Xu, Ruixiang Zhang, Jian Dou, Yushi Zhu, Jie Sun, and Shiliang Pu. Rpvnet: A deep and efficient range-point-voxel fusion network for lidar point cloud segmentation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 16024-16033, 2021.", + "[30] Xu Yan, Jiantao Gao, Chaoda Zheng, Chao Zheng, Ruimao Zhang, Shuguang Cui, and Zhen Li. 2dpass: 2d priors assisted semantic segmentation on lidar point clouds. In European Conference on Computer Vision, pages 677-695. Springer, 2022.", + "[31] Maosheng Ye, Shuangjie Xu, Tongyi Cao, and Qifeng Chen. Drinet: A dual-representation iterative learning network for point cloud segmentation. In Proceedings of the IEEE/CVF international conference on computer vision, pages 7447-7456, 2021.", + "[32] Yang Zhang, Zixiang Zhou, Philip David, Xiangyu Yue, Zerong Xi, Boqing Gong, and Hassan Foroosh. Polarnet: An improved grid representation for online lidar point clouds semantic segmentation. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9601-9610, 2020.", + "[33] Zixiang Zhou, Yang Zhang, and Hassan Foroosh. Panoptic-polarnet: Proposal-free lidar point cloud panoptic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13194-13203, 2021.", + "[34] Xinge Zhu, Hui Zhou, Tai Wang, Fangzhou Hong, Yuexin Ma, Wei Li, Hongsheng Li, and Dahua Lin. Cylindrical and asymmetrical 3d convolution networks for lidar segmentation. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 9939-9948, 2021." + ], + "bbox": [ + 78, + 90, + 468, + 864 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "754", + "bbox": [ + 486, + 945, + 509, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/9db8fa07-a91f-4043-9a71-b3d3e6b17388_model.json b/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/9db8fa07-a91f-4043-9a71-b3d3e6b17388_model.json new file mode 100644 index 0000000000000000000000000000000000000000..ff72b931ab254ba3e6d0dd253042cc18516eb2e6 --- /dev/null +++ b/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/9db8fa07-a91f-4043-9a71-b3d3e6b17388_model.json @@ -0,0 +1,1705 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.105, + 0.131, + 0.865, + 0.154 + ], + "angle": 0, + "content": "MemorySeg: Online LiDAR Semantic Segmentation with a Latent Memory" + }, + { + "type": "text", + "bbox": [ + 0.308, + 0.182, + 0.666, + 0.235 + ], + "angle": 0, + "content": "Enxu Li Sergio Casas Raquel Urtasun Waabi University of Toronto {tli, sergio, urtasun}@waabi.ai" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.269, + 0.314, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.302, + 0.474, + 0.725 + ], + "angle": 0, + "content": "Semantic segmentation of LiDAR point clouds has been widely studied in recent years, with most existing methods focusing on tackling this task using a single scan of the environment. However, leveraging the temporal stream of observations can provide very rich contextual information on regions of the scene with poor visibility (e.g., occlusions) or sparse observations (e.g., at long range), and can help reduce redundant computation frame after frame. In this paper, we tackle the challenge of exploiting the information from the past frames to improve the predictions of the current frame in an online fashion. To address this challenge, we propose a novel framework for semantic segmentation of a temporal sequence of LiDAR point clouds that utilizes a memory network to store, update and retrieve past information. Our framework also includes a novel regularizer that penalizes prediction variations in the neighborhood of the point cloud. Prior works have attempted to incorporate memory in range view representations for semantic segmentation, but these methods fail to handle occlusions and the range view representation of the scene changes drastically as agents nearby move. Our proposed framework overcomes these limitations by building a sparse 3D latent representation of the surroundings. We evaluate our method on SemanticKITTI, nuScenes, and PandaSet. Our experiments demonstrate the effectiveness of the proposed framework compared to the state-of-the-art. For more information, visit the project website: https://waabi.ai/research/memoryseg." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.755, + 0.21, + 0.77 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Semantic segmentation of LiDAR point clouds is a key component for the safe deployment of self-driving vehicles (SDV). It enables SDVs to enhance their understanding of the surrounding environment by categorizing every 3D point into specific classes of interest, such as vehicles, pedestrians, traffic signs, buildings, roadways, etc. This rich and precise 3D representation of the environment can then be used for various applications such as generating online or" + }, + { + "type": "image", + "bbox": [ + 0.501, + 0.272, + 0.692, + 0.409 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.697, + 0.272, + 0.895, + 0.41 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.413, + 0.895, + 0.482 + ], + "angle": 0, + "content": "Figure 1. Objects could be partially occluded in single frame LiDAR point cloud. Our approach learns a 3D latent memory representation for better contextualizing the online observations. We apply PCA [14] to reduce the latent dimension to 3 and plot as RGB. (Best viewed in color and zoomed-in.)" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.501, + 0.892, + 0.533 + ], + "angle": 0, + "content": "offline semantic maps, building localization priors, or making the shapes of an object tracker more precise." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.535, + 0.893, + 0.701 + ], + "angle": 0, + "content": "LiDAR data is typically captured as a continuous stream of data, where every fraction of a second (typically 100ms) a new point cloud is available. Despite this fact, most LiDAR segmentation approaches process each frame independently [15, 32, 28, 22, 34, 5, 29] due to the computational and memory complexity associated with processing large amounts of 3D point cloud data. However, reasoning about a single frame suffers from the sparsity of the observations, particularly at range, and has difficulty handling occluded objects. Furthermore, the absence of motion information can make categorizing certain objects difficult." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Several approaches [20, 19] utilize a sliding window approach, where a small set of past frames is processed independently at every time step. The main shortcoming of this approach is its limited temporal context (typically under 1 second) due to resource constraints, as processing multiple LiDAR scans at once is expensive. TemporalLidarSeg [8] proposed to utilize a latent spatial memory to retain information about the past while avoiding redundant computation every time a new scan is available, in a range view (RV) representation. However, the RV of the scene changes drastically as the SDV or the other actors move due to changes in perspective. As a result, the memory can be dominated by nearby objects, which appear larger in the RV representen" + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.946, + 0.511, + 0.957 + ], + "angle": 0, + "content": "745" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.081, + 0.092, + 0.468, + 0.333 + ], + "angle": 0, + "content": "tation, making it challenging to be updated from frame to frame. Occlusion can be particularly challenging as the occluder now occupies the same spatial region that was previously describing the occluded object. This limits the usefulness of the memory. In contrast to RV, 3D is a metric space where the distances between points are preserved regardless of the viewpoint or relative distance to the SDV. Thus, representing the memory in 3D enables learning size priors for different classes. It allocates equal representation power to them regardless of the distance to the SDV, and enables easy understanding of motion. Moreover, previously observed regions that are currently occluded can be remembered in the memory as the occluder and occluded objects occupy different 3D regions, even though they share the same space in RV. Despite these advantages, 3D memory has been overlooked in LiDAR semantic segmentation." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.336, + 0.468, + 0.487 + ], + "angle": 0, + "content": "In this paper we propose MEMORYSEG, a novel online LiDAR segmentation model that recurrently updates a sparse 3D latent memory as new observations are received, efficiently and effectively accumulating evidence from past observations. Fig. 1 illustrates the expressive power of such memory. In a single scan, objects are hard to identify due to sparsity (particularly at range) and lack of semantics, and occluded areas have no observations. In contrast, our latent memory is much denser, providing a rich context to separate different classes, especially in currently occluded regions." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.491, + 0.468, + 0.821 + ], + "angle": 0, + "content": "To achieve an effective memory update that takes into account both the past and the present for accurate decoding, our method addresses several challenges. First, we align the previous memory with the current observation in the latest ego frame, to compensate for the SDV motion. Second, the sparsity level of the memory and the observation embeddings are different, making fusion non-trivial. The latent memory is denser, and thus some currently unobserved locations may be present in the memory. Complementarily, some regions in the current scan have not been observed before, such as new observations appearing as the SDV drives further. For this reason, we propose a mechanism to fill in missing regions in the current observations and add new observations to the memory during the update. Third, other objects are also moving (potentially in opposite direction), thus fusing the memory and observation embeddings requires a large receptive field. We address this via a carefully designed architecture that achieves a large receptive field yet preserves sparsity for efficiency. Additionally, we introduce a novel point-level neighbourhood variation regularizer which penalizes significant differences in semantic predictions within local 3D neighborhoods." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.825, + 0.468, + 0.899 + ], + "angle": 0, + "content": "Extensive experiments in SemanticKITTI [2], nuScenes [4] and PandaSet [27] demonstrate that MEMORYSEG outperforms current state-of-the-art semantic segmentation methods that rely purely on LiDAR on multiple benchmarks." + }, + { + "type": "title", + "bbox": [ + 0.505, + 0.091, + 0.64, + 0.105 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.505, + 0.117, + 0.891, + 0.161 + ], + "angle": 0, + "content": "In this section, we start by reviewing LiDAR semantic segmentation approaches in the literature and then focus on methods proposed for temporal LiDAR reasoning." + }, + { + "type": "title", + "bbox": [ + 0.505, + 0.173, + 0.774, + 0.188 + ], + "angle": 0, + "content": "2.1. LiDAR Semantic Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.505, + 0.197, + 0.891, + 0.272 + ], + "angle": 0, + "content": "LiDAR-based semantic segmentation methods can be classified into four categories based on the type of data being processed: point-based [16, 17, 13, 24], projection-based [28, 7, 32], voxel-based [5, 34, 12], or a combination of the data representations [22, 29]." + }, + { + "type": "text", + "bbox": [ + 0.505, + 0.273, + 0.891, + 0.394 + ], + "angle": 0, + "content": "Point-based approaches [16, 17, 13, 24] operate directly on the point cloud, but most [17, 13, 24] rely on down-sampling to accommodate limited computational resources. KPCov [24] introduces customized spatial kernel-based point convolution which yields the most favorable outcomes compared to other point-based methods. However, it requires a significant amount of computational resources, which can limit its practicality in certain applications." + }, + { + "type": "text", + "bbox": [ + 0.505, + 0.395, + 0.891, + 0.529 + ], + "angle": 0, + "content": "Projection-based methods [28, 7, 32] involve projecting a 3D point cloud onto a 2D image plane, which can be done using either in spherical Range-View [28, 7], BirdEye-View [32], or multi-view representations [11]. These approaches usually operate in real-time, benefiting from efficient 2D CNN inference on GPUs. However, they suffer from significant information loss due to projection, which can prevent them from being on par with state-of-the-art methods." + }, + { + "type": "text", + "bbox": [ + 0.505, + 0.532, + 0.891, + 0.636 + ], + "angle": 0, + "content": "The emergence of 3D voxel-based approaches [5, 34, 12] can be attributed to recent advancements in sparse 3D convolutions [6, 21]. Typically, LiDAR point clouds are converted into Cartesian [5] or Cylindrical [34] voxels and then processed using sparse convolutions. They have demonstrated state-of-the-art performance, but reducing voxel resolution can result in significant loss of information." + }, + { + "type": "text", + "bbox": [ + 0.505, + 0.638, + 0.891, + 0.758 + ], + "angle": 0, + "content": "Recently, researchers have explored the potential of leveraging multiple data representations [22, 30, 29, 31] to benefit from the information acquired by each representation. For instance, SPVNAS [22] incorporates both pointwise features and 3D-voxel features in their network while learning to segment. Similarly, RPVNet [29] utilizes a trilateral structure in their network, where each branch adopts a distinct data representation mentioned earlier." + }, + { + "type": "text", + "bbox": [ + 0.505, + 0.759, + 0.891, + 0.834 + ], + "angle": 0, + "content": "Our method takes a similar approach to incorporate both point and voxel representations in the network. Voxel representations are utilized for contextual information learning, while point representations are employed to preserve fine-grained details, such as object boundaries and curvatures." + }, + { + "type": "title", + "bbox": [ + 0.505, + 0.847, + 0.754, + 0.862 + ], + "angle": 0, + "content": "2.2. Temporal LiDAR Reasoning" + }, + { + "type": "text", + "bbox": [ + 0.505, + 0.871, + 0.891, + 0.9 + ], + "angle": 0, + "content": "Previous methods [20, 19, 26] have attempted to integrate a small number of past frames to facilitate temporal" + }, + { + "type": "page_number", + "bbox": [ + 0.488, + 0.947, + 0.511, + 0.956 + ], + "angle": 0, + "content": "746" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.319 + ], + "angle": 0, + "content": "reasoning. For instance, SpSequenceNet [20] introduces cross-frame global attention, which uses information from the previous frame to emphasize features in the current frame. Additionally, it utilizes cross-frame local interpolation to combine local features from both the previous and current frame. Further, MetaRangeSeg [26] includes information from past frames by having the residual depth map as an additional feature to the input. However, these methods are not well-suited for continuous application to a temporal sequence of LiDAR point clouds. Firstly, they are inefficient as they discard previous observations and require the model to start from scratch each time a new point cloud is received. Secondly, they only aggregate temporal information within a short horizon, failing to capture the potential of temporal reasoning over a longer duration." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.323, + 0.473, + 0.566 + ], + "angle": 0, + "content": "Several works [8, 9] have attempted to incorporate temporal reasoning through a recurrent framework. Specifically, Duerr et al. [8] presents a recurrent segmentation architecture in RV, which uses previous observations as memory and aligns them temporally in the range image space. However, RV memory has limitations, such as prioritizing nearby objects, and suffering from contention of memory resources during occlusions (since information from behind the occluder and the occluder itself are now sharing the same memory entries). Further, StrObe [9] implemented a multi-scale 2D BEV memory for object detection enabling the network to take advantage of previous computations and process new LiDAR data incrementally. However, compared to object detection, semantic segmentation requires a more fine-grained and nuanced understanding of the scene and therefore a 3D memory is more suitable than 2D BEV." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.57, + 0.473, + 0.738 + ], + "angle": 0, + "content": "Our approach is distinct from previous methods as we propose an online LiDAR semantic segmentation framework utilizing a sparse 3D memory. By representing the memory in 3D, we preserve the distance between points regardless of viewpoint or distance from the SDV, allowing for size priors of different classes to be learned. Additionally, the memory also retains previously observed regions even when currently occluded, as occluders and occluded objects occupy different 3D regions, despite being in the same space in RV. Furthermore, we preserve fine-grained height details that are lost in the BEV memory." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.765, + 0.442, + 0.784 + ], + "angle": 0, + "content": "3.3D Memory-based LiDAR Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.471, + 0.903 + ], + "angle": 0, + "content": "In this section we introduce MEMORYSEG, an online semantic segmentation framework for streaming LiDAR point clouds that leverages a 3D latent memory to remember the past and better handle occlusions and sparse observations. In the remainder of this section, we first describe our model formulation, then present the network architecture and finally explain the learning process." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.091, + 0.688, + 0.107 + ], + "angle": 0, + "content": "3.1. Model Formulation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.113, + 0.892, + 0.234 + ], + "angle": 0, + "content": "Let \\(\\mathcal{P} = \\{\\mathcal{P}_t\\}_{t=1}^L\\) be a sequence of LiDAR sweeps where \\(L \\in \\mathbb{N}^+\\) is the sequence length and \\(t \\in [1, L]\\) is the time index. Each LiDAR sweep \\(\\mathcal{P}_t = (\\mathbf{G}_t, \\mathbf{F}_t)\\) is a \\(360^\\circ\\) scan of the surrounding with \\(N_t\\) unordered points. \\(\\mathbf{G}_t \\in \\mathbb{R}^{N_t \\times 3}\\) contains the Cartesian coordinates in the ego vehicle frame and \\(\\mathbf{F}_t \\in \\mathbb{R}^{N_t}\\) is the LiDAR intensity of the point. Let \\(\\mathbf{T}_{t-1 \\to t} \\in SE(3)\\) be the pose transformation from the vehicle frame at time \\(t-1\\) to \\(t\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.236, + 0.893, + 0.446 + ], + "angle": 0, + "content": "To make informed semantic predictions, in this paper we maintain a latent (or hidden) memory in 3D. This memory is sparse in nature since the majority of the 3D space is unoccupied. To represent this sparsity, we parametrize the memory at time \\( t \\) using a sparse set of voxels containing the coordinates \\( H_{G,t} \\in \\mathbb{R}^{M_t \\times 3} \\) and their corresponding learned embeddings \\( H_{F,t} \\in \\mathbb{R}^{M_t \\times d_m} \\). \\( M_t \\) is the number of voxel entries in the latent memory at time \\( t \\) and \\( d_m \\) is the embedding dimension. Preserving the voxel coordinates is important to perform alignment as the reference changes when the SDV moves. We utilize a voxel-based sparse representation as it provides notable computational benefits with respect to dense tensors as well as sparse representations at the point level without sacrificing performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.447, + 0.894, + 0.597 + ], + "angle": 0, + "content": "Inference follows a three-step process that is repeated every time a new LiDAR sweep is available: (i) the encoder takes in the most recent LiDAR point cloud at current time \\( t \\) and extracts point-level and voxel-level observation embeddings, (ii) the latent memory is updated taking into account the voxel-level embeddings from the new observations, and (iii) the semantic predictions are decoded by combining the point-level embeddings from the encoder and voxel-level embeddings from the updated memory. We refer the reader to Fig. 2 for an illustration of our method." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.598, + 0.894, + 0.779 + ], + "angle": 0, + "content": "The memory update stage faces challenges due to the changing reference frame as the SDV moves, different sparsity levels of memory and current LiDAR sweep, as well as the motion of other actors. To address these challenges, a Feature Alignment Module (FAM) is introduced to align the previous memory state with the current observation embeddings. Subsequently, an Adaptive Padding Module (APM) is utilized to fill in missing observations in the current data and add new observations to the memory. Then, a Memory Refinement Module (MRM) is employed to update the latent memory using padded observations. Next, we explain each component in more detail." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.894, + 0.903 + ], + "angle": 0, + "content": "Encoder: Following [22], our encoder is composed of a point-branch that computes point-level embeddings preserving the fine details and a voxel-branch that performs contextual reasoning through 3D sparse convolutional blocks [21]. The point-branch receives a 7-dimensional feature vector per point, with the xyz coordinates, intensity, and relative offsets to the nearest voxel center as features. It comprises two shared MLPs that output point embeddings," + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.945, + 0.511, + 0.956 + ], + "angle": 0, + "content": "747" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.101, + 0.091, + 0.868, + 0.246 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.25, + 0.895, + 0.293 + ], + "angle": 0, + "content": "Figure 2. An overview of our model, MEMORYSEG. After the encoder processes the LiDAR point cloud at time \\( t \\), the resulting feature map is utilized to update the latent memory (see Fig. 3 for more details about the memory update). Then, the decoder combines the refined memory with the point embeddings from the encoder to obtain semantic predictions." + }, + { + "type": "image", + "bbox": [ + 0.079, + 0.314, + 0.473, + 0.402 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.405, + 0.473, + 0.531 + ], + "angle": 0, + "content": "Figure 3. Overview of the latent memory update process. The latent memory embeddings \\((H_{G,t - 1},H_{F,t - 1})\\) are transformed to the ego frame at \\(t\\) with the Feature Alignment Module (FAM). Next, the Adaptive Padding Module (APM) is utilized to learn the padding of both memory and observation embeddings. The Memory Refinement Module (MRM) updates the latent memory by incorporating the padded observation embeddings. The updated memory is then passed to the decoder for generating semantic predictions. (Best viewed in color and zoomed-in.)" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.547, + 0.47, + 0.729 + ], + "angle": 0, + "content": "as illustrated in Fig. 2. We average point embeddings belonging to the same voxel from the first shared MLP over voxels of size \\( v_{b} \\) to obtain voxel features. These features are then processed through four residual blocks with 3D sparse convolutions, each downsampling the feature map by a factor of 2. Two additional residual blocks with 3D sparse convolutions are applied to upsample the sparse feature maps. Unlike a full U-Net [18] that recovers features at the original resolution, we only upsample to \\( \\frac{1}{4} \\) of the original size for computational efficiency reasons, and use the coarser features to update the latent memory before decoding finer details to output our semantic predictions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.471, + 0.902 + ], + "angle": 0, + "content": "Feature Alignment: The reference frame changes as the SDV moves. We propose the Feature Alignment Module (FAM) to transform the latent memory from the ego frame at \\( t - 1 \\) to \\( t \\) and align with the current observation embeddings. Specifically, we take the memory voxel coordinates \\( H_{G,t-1} \\) and use the pose information \\( \\mathbf{T}_{t-1 \\to t} \\) to project from the ego frame at \\( t - 1 \\) to \\( t \\). We then re-voxelize using the projected coordinates with a voxel size of \\( v_m \\). If multiple entries are inside the same memory voxel, we take the average of them to be the voxel feature. The resulting warped coordinates and embeddings of the memory in the" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.316, + 0.868, + 0.332 + ], + "angle": 0, + "content": "ego frame \\(t\\) are denoted as \\(\\tilde{H}_{G,t}\\) and \\(\\tilde{H}_{F,t}\\), respectively." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.334, + 0.892, + 0.756 + ], + "angle": 0, + "content": "Adaptive Padding: To handle the different sparsity of the latent memory and the voxel-level observation embeddings, we propose the Adaptive Padding Module (APM). We refer the readers to Fig. 3 for an illustration. First, we re-voxelize the encoder features with the same voxel size \\( v_{m} \\) where entries within the same voxel are averaged. We denote the resulting coordinates and embeddings as \\( X_{G} \\) and \\( X_{F} \\). Note that we omit \\( t \\) in this section for brevity. Let \\( x_{G} \\subseteq X_{G} \\) and \\( x_{F} \\subseteq X_{F} \\) be the coordinates and embeddings of the new observations at time \\( t \\) that are not present in the memory. To obtain an initial guess of the memory embedding for a new entry, we utilize a weighted aggregation approach within its surrounding neighbourhood. This involves taking into account the coordinate offsets relative to the existing neighbouring voxels in the memory, which provides insight into their importance for aggregation, similar to Continuous Conv [25]. In addition to this, we incorporate the feature similarities and feature distances as additional cues for the aggregation process. Encoding feature similarities is particularly useful for assigning weights to the neighborhood. In a dynamic scene with moving actors, the closest voxel may not always be the most important voxel. By providing feature similarities, the network can make more informed decisions. The goal of such completion is to make a hypothesis of the embedding at the previously unobserved location using the available information. More precisely, we add those entries in the memory where their coordinates are \\( h_{G}^{\\prime} = x_{G} \\) and the embedding of each voxel \\( j \\) are initialized as follows," + }, + { + "type": "equation", + "bbox": [ + 0.612, + 0.768, + 0.892, + 0.802 + ], + "angle": 0, + "content": "\\[\nh _ {F, j} ^ {\\prime} = \\sum_ {i \\in \\Omega_ {\\tilde {H}} (j)} w _ {j i} \\tilde {H} _ {F, i}, \\tag {1}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.508, + 0.823, + 0.892, + 0.86 + ], + "angle": 0, + "content": "\\[\nw _ {j i} = \\psi \\left(\\tilde {H} _ {G, i} - x _ {G, j}, \\| \\tilde {H} _ {F, i} - x _ {F, j} \\|, \\frac {\\tilde {H} _ {F , i} \\cdot x _ {F , j}}{\\| \\tilde {H} _ {F , i} \\| \\| x _ {F , j} \\|}\\right), \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.869, + 0.895, + 0.902 + ], + "angle": 0, + "content": "where \\(i\\) and \\(j\\) are voxel indices, \\(\\Omega_{\\tilde{H}}(j)\\) is the k-nearest-neighborhood of voxel \\(j\\) in \\(\\tilde{H}_G\\), and \\(\\psi\\) is a shared MLP" + }, + { + "type": "page_number", + "bbox": [ + 0.487, + 0.946, + 0.511, + 0.956 + ], + "angle": 0, + "content": "748" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.122 + ], + "angle": 0, + "content": "followed by a softmax layer on the dimension of neighbourhood to ensure \\(\\sum_{i}w_{ji} = 1\\)" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.122, + 0.47, + 0.197 + ], + "angle": 0, + "content": "Second, we identify the regions in the memory that are unseen in the current observation and denote their coordinates and embeddings as \\(\\tilde{h}_G \\subseteq \\tilde{H}_G\\) and \\(\\tilde{h}_F \\subseteq \\tilde{H}_F\\). We add entries \\(x_G'\\) and \\(x_F'\\) to complete the current observation in a similar manner." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.2, + 0.47, + 0.247 + ], + "angle": 0, + "content": "Memory Refinement: We design a sparse version of a ConvGRU [1] to update the latent memory \\( H_{F,t-1}^{\\prime} \\) using the current padded observation embeddings \\( X_{F,t}^{\\prime} \\) as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.149, + 0.26, + 0.469, + 0.341 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} r _ {t} = \\operatorname {s i g m o i d} \\left[ \\Psi_ {r} \\left(X _ {F, t} ^ {\\prime}, H _ {F, t - 1} ^ {\\prime}\\right) \\right], \\\\ z _ {t} = \\operatorname {s i g m o i d} \\left[ \\Psi_ {z} \\left(X _ {F, t} ^ {\\prime}, H _ {F, t - 1} ^ {\\prime}\\right) \\right], \\\\ \\hat {H} _ {F, t} = \\tanh \\left[ \\Psi_ {u} \\left(X _ {F, t} ^ {\\prime}, r _ {t} \\cdot H _ {F, t - 1} ^ {\\prime}\\right) \\right], \\tag {3} \\\\ H _ {F, t} = \\hat {H} _ {F, t} \\cdot z _ {t} + H _ {F, t - 1} ^ {\\prime} \\cdot (1 - z _ {t}), \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.352, + 0.469, + 0.457 + ], + "angle": 0, + "content": "where \\(\\Psi_r, \\Psi_z, \\Psi_u\\) are sparse 3D convolutional blocks with downsampling layers that aim to expand the receptive field and upsampling layers that restore the embeddings to their original size. \\(r_t\\) and \\(z_t\\) are learned signals to reset or update the memory, respectively. We refer the readers to the supplementary material about the detailed architecture of the sparse convolutional blocks." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.46, + 0.47, + 0.642 + ], + "angle": 0, + "content": "Decoder: Our decoder consists of an MLP, two residual blocks with sparse 3D convolutions, and a linear semantic header. Specifically, we first take the corresponding memory embeddings at coordinates \\(\\mathbf{G}_t\\) and add with the point embeddings from the encoder. The resulting combined embeddings are then voxelized with voxel size of \\(\\frac{v_b}{4}\\) and further processed by two residual blocks that upsample the feature maps back to the original resolution. In parallel, an MLP takes the point embeddings before voxelization to retain the fine-grained details. Finally, the semantic header takes the combination of voxel and point embeddings to obtain per-point semantic predictions." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.644, + 0.47, + 0.69 + ], + "angle": 0, + "content": "Memory Initialization: At the start of the sequence (\\(t = 0\\)), the first observation is used to initialize memory, with \\(H_{G,0} = X_{G,0}\\) and \\(H_{F,0} = X_{F,0}\\)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.7, + 0.186, + 0.715 + ], + "angle": 0, + "content": "3.2. Learning" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.723, + 0.469, + 0.784 + ], + "angle": 0, + "content": "We learn our segmentation model by minimizing a linear combination of conventional segmentation loss functions [13, 34, 22] and a novel point-wise regularizer to better supervise the network training." + }, + { + "type": "equation", + "bbox": [ + 0.152, + 0.797, + 0.469, + 0.814 + ], + "angle": 0, + "content": "\\[\nJ = \\beta_ {w c e} J _ {w c e} + \\beta_ {l s} J _ {l s} + \\beta_ {r e g} J _ {r e g}. \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Here, \\( J_{wce} \\) denotes cross-entropy loss, weighted by the inverse frequency of classes, to address class imbalance in the dataset. The Lovasz Softmax Loss (\\( J_{ls} \\)) [3] is used to train the network, as it is a differentiable surrogate for the non-convex intersection over union (IoU) metric, which is" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.138 + ], + "angle": 0, + "content": "a commonly used evaluation metric for semantic segmentation. Additionally, \\( J_{reg} \\) corresponds to our proposed pointwise regularizer. \\( \\beta_{reg}, \\beta_{wce} \\) and \\( \\beta_{ls} \\) are hyperparameters." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.14, + 0.892, + 0.201 + ], + "angle": 0, + "content": "Point-wise Smoothness: Our regularizer is designed to limit significant variations in semantic predictions within the 3D neighborhood of each point, except when these variations occur at the class boundary. Formally," + }, + { + "type": "equation", + "bbox": [ + 0.567, + 0.215, + 0.892, + 0.296 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} J _ {r e g} = \\frac {1}{N _ {t}} \\sum_ {\\substack {i = 1 \\\\ 1}} ^ {N _ {t}} | \\Delta (Y, i) - \\Delta (\\hat {Y}, i) |, \\tag{5} \\\\ \\Delta (Y, i) = \\Big | \\frac {1}{| \\Omega_ {\\mathcal {P} _ {t}} (i) |} \\sum_ {j \\in \\Omega_ {\\mathcal {P} _ {t}} (i)} | y _ {i} - y _ {j} | \\Big |. \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.31, + 0.892, + 0.477 + ], + "angle": 0, + "content": "Here, \\(\\Delta(Y, i)\\) represents the ground truth semantic variation around point \\(i\\), while \\(\\Delta(\\hat{Y}, i)\\) corresponds to the predicted semantic variation around point \\(i\\). We use \\(\\hat{Y} \\in \\mathbb{R}^{N_t \\times C}\\) to denote the predicted semantic distribution over \\(C\\) classes, and \\(Y \\in \\mathbb{R}^{N_t \\times C}\\) to denote the ground truth semantic one-hot label. The variable \\(y_i\\) represents the \\(i\\)-th element of \\(Y\\). \\(\\Omega_{\\mathcal{P}_t}(i)\\) denotes the neighborhood of point \\(i\\) in \\(\\mathcal{P}_t\\), and \\(|\\Omega_{\\mathcal{P}_t}(i)|\\) represents the number of points in the neighborhood. The inspiration for this regularizer comes from a study by [11] that penalizes adjacent pixel prediction variations with the ground truth." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.494, + 0.633, + 0.51 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.52, + 0.892, + 0.702 + ], + "angle": 0, + "content": "In this section, we thoroughly analyze the performance of our method on three different datasets: SemanticKITTI [2], nuScenes [4], and PandaSet [27]. These datasets were collected using different LiDAR sensors and in diverse geographical regions. Our results demonstrate that MEMORY-SEG outperforms the current state of the art in all benchmarks. Additionally, we conduct ablation studies to understand the impact of our contributions. We demonstrate that incorporating a 3D sparse latent memory improves semantic predictions, with a very significant gain in long-range areas as these are sparser and more often partially obstructed than short-range regions." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.704, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Datasets: We benchmark our approach on three large-scale autonomous driving datasets: SemanticKITTI [2] consists of 22 sequences from the KITTI Odometry Dataset [10], which was collected in Germany using a Velodyne HDL-64E LiDAR. We use the standard split where sequences 0 to 10 are used for training (with sequence 8 for validation), and sequences 11 to 21 are held for testing. We follow the standard setting where semantic labels are mapped to 19 classes for the single-scan benchmark and 25 for the multi-scan benchmark. In the latter, all movable classes are further divided into moving and non-moving classes. Given that prior research on temporal aggregation for semantic segmentation is more prevalent in" + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.946, + 0.511, + 0.957 + ], + "angle": 0, + "content": "749" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.081, + 0.089, + 0.89, + 0.212 + ], + "angle": 0, + "content": "
MethodmIoUCarBicycleMoonecycleTruckOther VehiclePersonBicyclistMoonecyclistRoadParkingSidewalkOther GroundBuildingFenceVegetationTrunkTerrainPoleTraffic Signcar (m)bicyclist (m)person (m)motorcycle (m)other-vehicle (m)truck (m)
TangentConv [23]34.184.92.018.221.118.51.60.00.083.938.364.015.385.849.179.543.256.736.431.240.31.16.41.930.142.2
DarkNet53Seg [2]41.684.130.432.920.220.77.50.00.091.664.975.327.585.256.578.450.764.838.153.361.514.115.20.228.937.8
KPConv [24]51.293.744.947.242.538.621.60.00.086.558.470.526.790.864.584.670.366.057.053.969.467.467.547.24.75.8
Cylinder3D [34]52.594.667.663.841.338.812.51.70.290.765.074.532.392.666.085.872.068.963.161.474.968.365.711.90.10.0
SpSequenceNet [20]43.188.524.026.229.222.76.30.00.090.157.673.927.191.266.884.066.065.750.848.753.241.226.236.22.30.1
TemporalLidarSeg [8]47.092.147.740.939.235.014.40.00.091.859.675.823.289.863.882.362.564.752.660.468.242.840.412.912.42.1
TemporalLatticeNet [19]47.191.635.436.126.923.09.40.00.091.559.375.327.589.665.384.666.770.457.260.459.741.751.048.85.90.0
Meta-RangeSeg [26]49.790.850.049.529.534.816.60.00.090.862.974.826.589.862.182.865.766.556.264.569.060.457.922.016.62.6
MEMORYSEG [ours]58.394.068.368.851.340.927.00.32.889.964.374.829.292.269.384.875.170.165.568.571.774.471.773.915.113.6
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.08, + 0.213, + 0.892, + 0.266 + ], + "angle": 0, + "content": "Table 1. Comparison to the state-of-the-art methods on the test set of SemanticKITTI [2] multi-scan benchmark. (m) indicates moving. We include LiDAR-only published approaches at the time of submission. These approaches are categorized into two groups: the first group includes methods that aim for single-scan segmentation but use multiple aggregated frames as input; the second group consists of methods that introduce temporal aggregation modules explicitly tailored for handling multiple scans. Metrics are provided in [%]." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.28, + 0.468, + 0.581 + ], + "angle": 0, + "content": "the multi-scan benchmark, we consider it more appropriate for evaluating our proposed method. Single-scan benchmark results are also provided in the supplementary material. nuScenes [4] was collected in Boston and Singapore using a Velodyne HDL-32E LiDAR sensor, which captures sparser point clouds that pose extra challenges for semantic reasoning. The dataset contains a total of 1000 scenes, with 700 scenes used for training, 150 for validation, and the remaining 150 held out for testing. Each scene contains about 40 labeled frames recorded at \\(2\\mathrm{Hz}\\). We follow the standard setting which maps 31 fine-grained classes to 16 classes for training and evaluation. PandaSet [27] provides short sequences of temporal data but with a large number of moving actors in Silicon Valley. This dataset was collected using a Hesai-Pandar64 LiDAR and consists of 103 sequences, each with a length of 8 seconds. Following [8], we grouped the original fine-grained semantic classes into 14 for training and testing, trying to match the classes in other popular segmentation benchmarks [2, 4]. We also used the same train/Validation/test split as in the reference paper." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.585, + 0.468, + 0.9 + ], + "angle": 0, + "content": "Implementation details: For all datasets, we first train the network without the memory update for single-scan segmentation for 50 epochs. Then, we freeze the encoder and train the memory update block and decoder in a recurrent fashion for an additional 20 epochs. During each training iteration, we use the first 10 consecutive sweeps as warmup memory, and then train the network with backpropagation through time (BPTT) on the next 3 frames. The memory voxel size \\( v_{m} \\) is \\( 0.5\\mathrm{m} \\), and the embedding dimension \\( d_{m} \\) is 128. We use the AdamW optimizer with a starting learning rate of 0.003 and a decay factor of 0.9. During training, we use data augmentation including global scaling sampled at random from [0.80, 1.20], translation sampled from [0, 0.2] m on all three axes, and global rotation around the Z axis with a random angle sampled from \\( [-\\pi ,\\pi ] \\). We set the loss weights \\( \\beta_{wce} \\) to 1, \\( \\beta_{ls} \\) to 2, and \\( \\beta_{reg} \\) to 500. We set the regularizer neighborhood \\( \\Omega_{P_t}(i) \\) to be the closest 32 points around point \\( i \\), and use a padding neighbourhood \\( \\Omega_{\\tilde{H}}(j) \\) to be the closest 5 voxels of voxel \\( j \\). All experiments are conducted using 4 NVIDIA T4 GPUs with a batch size of 1 per GPU. During evaluation, we unroll each sequence from the" + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.28, + 0.891, + 0.324 + ], + "angle": 0, + "content": "first frame to the end and follow [34, 12] to apply test-time-augmentation, i.e. averaging prediction scores of 10 forward passes with augmented input from a single model." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.326, + 0.891, + 0.519 + ], + "angle": 0, + "content": "To adapt to the uniqueness of each dataset, we consider the following per-dataset settings. To train on the SemanticKITTI dataset, we set the voxel size \\( v_{b} \\) to 0.05 m. Due to the limited quantities of movable actors in this dataset, following [33] we generate a library of instances from the training sequences and randomly inject 5 objects over the ground classes at each frame during training. To improve the ability to separate classes into moving and non-moving actors, we add another linear header to classify points as moving or static and fuse the results from the semantic header. More implementation details are provided in the supplementary material. For nuScenes, the voxel size is set to 0.1 m, and 0.125 m for PandaSet." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.523, + 0.891, + 0.674 + ], + "angle": 0, + "content": "Metrics: We follow existing works [34, 5, 29] and use the intersection over union (IoU) averaged over all classes as the main metric (mIoU). Class-wise IoUs are also reported. Comparison against state-of-the-art: Our results are compared with other state-of-the-art approaches on the test set of three datasets in Tab. 1 to 3. We include approaches that use LiDAR only for fair comparison. Notably, our proposed method outperforms all prior works on all three datasets, demonstrating its generalizability across various LiDAR sensors and different geographical regions." + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.676, + 0.891, + 0.9 + ], + "angle": 0, + "content": "Tab. 1 presents a comparison of our approach on the SemanticKITTI multi-scan benchmark, which is designed to evaluate methods that focus on temporal aggregation for semantic segmentation. The other methods in the table are divided into two groups. The first group consists of baselines that are designed for single-scan segmentation but aggregate multiple consecutive frames as input at the cost of higher memory consumption and longer runtime. In contrast, the second group proposes temporal aggregation modules specifically to handle multiple scans. It is worth noting that our proposed method performs significantly better than all of these approaches. MEMORYSEG demonstrates exceptional performance in segmenting dynamic actors, such as moving bicyclist, motorcyclist, and person. These substantial improvements can be attributed to the proposed re" + }, + { + "type": "page_number", + "bbox": [ + 0.488, + 0.947, + 0.511, + 0.957 + ], + "angle": 0, + "content": "750" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.089, + 0.89, + 0.198 + ], + "angle": 0, + "content": "
MethodmIoUFW-mIoUBarrierBicycleBusCarConstructionMotorcyclePedestrainTraffic ConeTrailerTruckDrivableOther FlatSidewalkTerrainMannmadeVegetation
PolarNet [32]69.487.472.216.877.086.551.169.764.854.169.763.596.667.177.772.187.184.5
Cylinder3D [34]77.289.982.829.884.389.463.079.377.273.484.669.197.770.280.375.590.487.6
SPVCNN [22]77.489.780.030.091.990.864.779.075.670.981.074.697.469.280.076.189.387.1
(AF)2-S3Net [5]78.388.578.952.289.984.277.474.377.372.083.973.897.166.577.574.087.786.8
MEMORYSEG [ours]80.691.484.940.291.292.471.273.585.977.888.076.497.969.081.277.692.689.7
" + }, + { + "type": "table_caption", + "bbox": [ + 0.08, + 0.199, + 0.891, + 0.224 + ], + "angle": 0, + "content": "Table 2. Comparison to the state-of-the-art methods on the test set of nuScenes [4] LiDAR semantic segmentation benchmark. We include LiDAR-only published approaches at the time of submission. Metrics are provided in [%]" + }, + { + "type": "table", + "bbox": [ + 0.161, + 0.236, + 0.808, + 0.341 + ], + "angle": 0, + "content": "
MethodmIoUCarBicycleMotorcycleTruckOther VehiclePersonRoadRoad BarriersSidewalkBuildingVegetationTerrainBackgroundTraffic Sign
SqueezeSegv3 [28]55.792.824.118.036.554.363.091.111.971.386.285.061.363.220.6
SalsaNext [7]57.892.140.731.728.756.269.090.022.667.185.683.458.563.320.6
TemporalLidarSeg [8]60.093.733.638.037.159.972.091.114.670.688.288.463.868.420.7
SPVCNN [22]64.795.838.146.344.074.178.691.228.370.387.287.561.567.535.6
MEMORYSEG [ours]70.397.260.258.462.974.382.692.127.774.189.490.764.972.836.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.151, + 0.342, + 0.815, + 0.354 + ], + "angle": 0, + "content": "Table 3. Comparison to the state-of-the-art methods on the test set of PandaSet [27]. Metrics are provided in [%]." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.367, + 0.468, + 0.532 + ], + "angle": 0, + "content": "current framework, which implicitly encode the motion of moving actors in the 3D latent memory. Furthermore, we also demonstrate the effectiveness of our approach on the single-scan benchmark of the same dataset. We refer the readers to the supplementary material for the detailed results. This is a more competitive benchmark focusing on single-scan semantic segmentation where previous research has focused on proposing various architectures [5, 29, 34] or knowledge distillation techniques [12]. Our results show that MEMORYSEG can outperform these methods, which are highly optimized for this benchmark." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.536, + 0.468, + 0.747 + ], + "angle": 0, + "content": "Results on nuScenes [4] benchmark are presented in Tab. 2. MEMORYSEG outperforms the previous state-of-the-art. Our method is particularly effective in smaller classes such as barriers, pedestrians, and traffic cones, which present challenges for semantic segmentation networks due to the sparser point clouds available in this dataset. However, our approach overcomes this limitation by using a 3D latent memory to improve semantic reasoning of the sparse points. Additionally, we observe significant gains in the background classes, such as sidewalk, terrain, and manmade, which often rely on understanding of the surrounding to be segmented correctly. Our method improves the contextual reasoning by accumulating past observations using a latent memory representation." + }, + { + "type": "text", + "bbox": [ + 0.081, + 0.75, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Finally, we compare our results with the state-of-the-art methods on PandaSet [27] and report the test set IoUs in Tab. 3. Our proposed method also achieves state-of-the-art performance in this dataset. Notably, our approach outperforms others by a large margin in almost all classes. We highlight that MEMORYSEG consistently outperforms TemporalLidarSeg [8] across multiple benchmarks, a method that also proposes a latent memory but in RV instead of 3D. These findings confirm our hypothesis that the 3D latent memory approach is more effective than using RV in" + }, + { + "type": "text", + "bbox": [ + 0.504, + 0.367, + 0.828, + 0.382 + ], + "angle": 0, + "content": "accurately segmenting objects in 3D point clouds." + }, + { + "type": "text", + "bbox": [ + 0.503, + 0.388, + 0.89, + 0.9 + ], + "angle": 0, + "content": "Importance of the memory: Fig. 4 highlights the significance of incorporating memory, particularly in longer range regions where point clouds are much sparser. To assess the effectiveness of the learned latent memory, we compare against our encoder and decoder without the memory update module as the single frame baseline (SFB). Our proposed network consistently outperforms the SFB in all regions, with the most significant improvement observed in the long-range region of nuScenes, where points are sparser and more difficult to contextualize. Thanks to the 3D sparse latent memory that accumulates semantic embeddings of past frames, our proposed approach performs much better than the SFB, particularly in those challenging regions. Fig. 5 provides similar insights. In the top-left of the figure, the SFB fails to segment a partially occluded vehicle located behind a fence. In contrast, our proposed approach initially segments the vehicle as other vehicle class, but as the ego vehicle advances, the 3D latent memory accumulates and refines through new observations, enabling the network to correctly identify the vehicle as a car after two sweeps. This illustration further confirms that the proposed 3D latent memory provides better contextualization of sparse objects that are partially occluded. Additional qualitative results are provided in the supplementary materials. We also quantitatively demonstrate the importance of memory in Tab. 4. M1 builds on SFB and incorporates FAM and MRM. Note that both FAM and MRM are essential for updating the latent memory continuously. FAM aligns the sparse 3D latent memory in the traveling ego frame, while MRM helps in learning to reset and update the memory recurrently. APM is replaced with zero-padding in M1 to highlight the significance of memory. M1 shows a \\(2.3\\%\\) improvement in the mIoU metric compared to SFB, attributed to the ability of the sparse 3D latent memory to aggregate information in the" + }, + { + "type": "page_number", + "bbox": [ + 0.488, + 0.947, + 0.509, + 0.957 + ], + "angle": 0, + "content": "751" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.088, + 0.091, + 0.226, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.228, + 0.091, + 0.324, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.325, + 0.092, + 0.46, + 0.182 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.187, + 0.468, + 0.214 + ], + "angle": 0, + "content": "Figure 4. Comparison of MEMORYSEG with single frame baseline (SFB) on the validation set with different distance-range." + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.222, + 0.468, + 0.389 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.395, + 0.468, + 0.436 + ], + "angle": 0, + "content": "Figure 5. Predictions of MEMORYSEG over time are illustrated in the bottom row. We include the prediction from the single frame baseline (SFB) and ground truth with color code at the top." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.467, + 0.45, + 0.482 + ], + "angle": 0, + "content": "temporal dimension as the ego moves through the scene." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.487, + 0.47, + 0.775 + ], + "angle": 0, + "content": "Influence of adaptive padding: In this section, we compare our proposed APM with zero padding and Continuous Conv [25]. The results are presented in Tab. 4. M2 is an extension of M1 that introduces adaptive padding on both observation and memory embeddings when they are aligned. However, the padded entries are only processed using the relative coordinates in the neighborhood, similar to Continuous Conv [25] with the attention mechanism. A slight improvement of \\(0.2\\%\\) is observed when new observations in the latent memory are initialized with a learned guess instead of all zeros. To further improve the performance of the network, M4 exploits feature similarities and distances in APM. When assigning an initial embedding to a new entry, both the relative position and the similarity to neighbors are considered. This is particularly useful for moving actors in the scene, where the network should learn to start with a guess with a similar embedding in the neighborhood, rather than the closest entry. By comparing M0 with M3 further confirms the usefulness of the proposed APM." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.78, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Influence of memory refinement: In M3 of Tab. 4, we replace our proposed MRM with a vanilla sparse ConvGRU [1], which has a limited receptive field due to the convolution kernel size, making it challenging for fast-moving actors. However, MRM overcomes this limitation by down-sampling features to increase the receptive field. This improves the learning of meaningful reset and update gates for refining the latent memory." + }, + { + "type": "table", + "bbox": [ + 0.517, + 0.089, + 0.878, + 0.199 + ], + "angle": 0, + "content": "
FAMAPMMRMmIoU
CCOursSCGOurs
SFB67.2
M0✓✓✓68.9
M1✓✓69.5
M2✓✓✓69.7
M3✓✓✓69.7
M4✓✓✓70.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.199, + 0.892, + 0.268 + ], + "angle": 0, + "content": "Table 4. Ablation on the proposed components in the network. Metrics are mIoU on the validation set of SemanticKITTI [2] provided in [%]. FAM: Feature Alignment Module, APM: Adaptive Padding Module, CC: padding using Continuous Conv [25], SCG: Sparse ConvGRU [1]. MRM: Memory Refinement Module." + }, + { + "type": "table", + "bbox": [ + 0.533, + 0.281, + 0.86, + 0.324 + ], + "angle": 0, + "content": "
RegularizerSemanticKITTInuScenesPandaSet
66.472.964.7
✓67.276.766.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.334, + 0.892, + 0.375 + ], + "angle": 0, + "content": "Table 5. Ablation on the model performance with and without the proposed regularizer. Metrics are mIoU on the validation set provided in [%]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.389, + 0.892, + 0.539 + ], + "angle": 0, + "content": "Influence of the regularizer: To demonstrate the effectiveness of our regularizer to train semantic segmentation networks on point clouds with different characteristics, we ablate this loss on the three datasets and summarize the results in Tab. 5. The results consistently show that incorporating the regularizer leads to performance improvements. The regularizer provides additional supervision on variations and boundaries, which is particularly beneficial for nuScenes. We note once again that this dataset has sparser point clouds than the other two." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.543, + 0.892, + 0.664 + ], + "angle": 0, + "content": "Parameter count and runtime comparison: MEMORY-SEG incurs only a relatively small computational overhead of \\(23\\%\\) more parameters and \\(20\\%\\) runtime than SFB. On the other hand, when naively concatenating the past five frames as the input to the model, despite having the same number of parameters as SFB, it takes 1.58 times longer (32% slower than our method) while only exploiting a limited 0.5-second window from the past." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.679, + 0.618, + 0.694 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.892, + 0.901 + ], + "angle": 0, + "content": "In this paper, we have proposed a novel online LiDAR segmentation model named MEMORYSEG, which utilizes a sparse 3D latent memory to recurrently accumulate learned semantic embeddings from past observations. We also presented a novel variation regularizer to supervise the learning of 3D semantic segmentation on point clouds. Our results demonstrate that our approach achieve state-of-the-art performance on three large-scale datasets. This improved performance can be attributed to the ability of the latent memory to better contextualize objects in the scene. Looking ahead, our future work will focus on integrating instance segmentation and tracking to develop an end-to-end memory-augmented panoptic segmentation framework." + }, + { + "type": "page_number", + "bbox": [ + 0.486, + 0.946, + 0.511, + 0.957 + ], + "angle": 0, + "content": "752" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.47, + 0.186 + ], + "angle": 0, + "content": "[1] Nicolas Ballas, Li Yao, Chris Pal, and Aaron C. Courville. Delving deeper into convolutional networks for learning video representations. In 4th International Conference on Learning Representations, ICLR 2016, San Juan, Puerto Rico, May 2-4, 2016, Conference Track Proceedings, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.188, + 0.472, + 0.257 + ], + "angle": 0, + "content": "[2] Jens Behley, Martin Garbade, Andres Milioto, Jan Quenzel, Sven Behnke, Cyril Stachniss, and Jürgen Gall. Semantickitti: A dataset for semantic scene understanding of lidar sequences. In 2019 IEEE/CVF International Conference on Computer Vision, pages 9296-9306. IEEE, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.259, + 0.471, + 0.342 + ], + "angle": 0, + "content": "[3] Maxim Berman, Amal Rannen Triki, and Matthew B Blaschko. The lovasz-softmax loss: A tractable surrogate for the optimization of the intersection-over-union measure in neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4413-4421, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.344, + 0.47, + 0.428 + ], + "angle": 0, + "content": "[4] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11621-11631, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.43, + 0.47, + 0.513 + ], + "angle": 0, + "content": "[5] Ran Cheng, Ryan Razani, Ehsan Taghavi, Enxu Li, and Bingbing Liu. af2-s3net: Attentive feature fusion with adaptive feature selection for sparse semantic segmentation network. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 12547-12556, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.515, + 0.47, + 0.584 + ], + "angle": 0, + "content": "[6] Christopher Choy, JunYoung Gwak, and Silvio Savarese. 4d spatio-temporal convnets: Minkowski convolutional neural networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 3075-3084, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.587, + 0.47, + 0.643 + ], + "angle": 0, + "content": "[7] Tiago Cortinhal, George Tzelepis, and Eren Erdal Aksoy. Salsanext: Fast semantic segmentation of lidar point clouds for autonomous driving. In 2020 IEEE Intelligent Vehicles Symposium (IV), pages 655-661, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.645, + 0.47, + 0.713 + ], + "angle": 0, + "content": "[8] Fabian Duerr, Mario Pfaller, Hendrik Weigel, and Jürgen Beyerer. Lidar-based recurrent 3d semantic segmentation with temporal memory alignment. In 2020 International Conference on 3D Vision (3DV), pages 781-790. IEEE, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.716, + 0.47, + 0.8 + ], + "angle": 0, + "content": "[9] Davi Frossard, Shun Da Suo, Sergio Casas, James Tu, and Raquel Urtasun. Strobe: Streaming object detection from lidar packets. In Jens Kober, Fabio Ramos, and Claire Tomlin, editors, Proceedings of the 2020 Conference on Robot Learning, volume 155 of Proceedings of Machine Learning Research, pages 1174-1183. PMLR, 16-18 Nov 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.802, + 0.47, + 0.857 + ], + "angle": 0, + "content": "[10] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the kitti vision benchmark suite. In Conference on Computer Vision and Pattern Recognition (CVPR), 2012." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.859, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[11] Martin Gerdzhev, Ryan Razani, Ehsan Taghavi, and Liu Bingbing. Tornado-net: multiview total variation semantic segmentation with diamond inception module. In 2021" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.472, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "IEEE International Conference on Robotics and Automation (ICRA), pages 9543-9549, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.121, + 0.892, + 0.188 + ], + "angle": 0, + "content": "[12] Yuenan Hou, Xinge Zhu, Yuexin Ma, Chen Change Loy, and Yikang Li. Point-to-voxel knowledge distillation for lidar semantic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8479-8488, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.19, + 0.892, + 0.272 + ], + "angle": 0, + "content": "[13] Qingyong Hu, Bo Yang, Linhai Xie, Stefano Rosa, Yulan Guo, Zhihua Wang, Niki Trigoni, and Andrew Markham. Randla-net: Efficient semantic segmentation of large-scale point clouds. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 11108-11117, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.274, + 0.892, + 0.3 + ], + "angle": 0, + "content": "[14] Ian Jolliffe. *Principal Component Analysis*. John Wiley & Sons, Ltd, 2005." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.302, + 0.892, + 0.357 + ], + "angle": 0, + "content": "[15] Andres Milioto, Ignacio Vizzo, Jens Behley, and Cyril Stachniss. Rangenet++: Fast and accurate lidar semantic segmentation. In Proc. of the IEEE/RSJ Intl. Conf. on Intelligent Robots and Systems (IROS), 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.358, + 0.892, + 0.413 + ], + "angle": 0, + "content": "[16] Charles R Qi, Hao Su, Kaichun Mo, and Leonidas J Guibas. Pointnet: Deep learning on point sets for 3d classification and segmentation. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 652-660, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.414, + 0.892, + 0.469 + ], + "angle": 0, + "content": "[17] Charles Ruizhongtai Qi, Li Yi, Hao Su, and Leonidas J Guibas. Pointnet++: Deep hierarchical feature learning on point sets in a metric space. Advances in neural information processing systems, 30, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.47, + 0.892, + 0.552 + ], + "angle": 0, + "content": "[18] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In Medical Image Computing and Computer-Assisted Intervention-MICCAI 2015: 18th International Conference, Munich, Germany, October 5-9, 2015, Proceedings, Part III 18, pages 234-241. Springer, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.554, + 0.892, + 0.607 + ], + "angle": 0, + "content": "[19] Peer Schütt, Radu Alexandru Rosu, and Sven Behnke. Abstract flow for temporal semantic segmentation on the permutohedral lattice. In Proceedings of the IEEE International Conference on Robotics and Automation (ICRA), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.609, + 0.892, + 0.677 + ], + "angle": 0, + "content": "[20] Hanyu Shi, Guosheng Lin, Hao Wang, Tzu-Yi Hung, and Zhenhua Wang. Spsequencenet: Semantic segmentation network on 4d point clouds. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 4574-4583, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.679, + 0.892, + 0.732 + ], + "angle": 0, + "content": "[21] Haotian Tang, Zhijian Liu, Xiuyu Li, Yujun Lin, and Song Han. Torchsparse: Efficient point cloud inference engine. Proceedings of Machine Learning and Systems, 4:302-315, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.734, + 0.892, + 0.816 + ], + "angle": 0, + "content": "[22] Haotian Tang, Zhijian Liu, Shengyu Zhao, Yujun Lin, Ji Lin, Hanrui Wang, and Song Han. Searching efficient 3d architectures with sparse point-voxel convolution. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23–28, 2020, Proceedings, Part XXVIII, pages 685–702. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.818, + 0.892, + 0.872 + ], + "angle": 0, + "content": "[23] Maxim Tatarchenko, Jaesik Park, Vladlen Koltun, and Qian-Yi Zhou. Tangent convolutions for dense prediction in 3d. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3887-3896, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.874, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[24] Hugues Thomas, Charles R Qi, Jean-Emmanuel Deschaud, Beatrix Marcotegui, François Goulette, and Leonidas J" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.487, + 0.946, + 0.511, + 0.957 + ], + "angle": 0, + "content": "753" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.469, + 0.134 + ], + "angle": 0, + "content": "Guibas. Kpconv: Flexible and deformable convolution for point clouds. In Proc. of the IEEE International Conference on Computer Vision, pages 6411-6420, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.469, + 0.205 + ], + "angle": 0, + "content": "[25] Shenlong Wang, Simon Suo, Wei-Chiu Ma, Andrei Pokrovsky, and Raquel Urtasun. Deep parametric continuous convolutional neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2589-2597, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.207, + 0.469, + 0.261 + ], + "angle": 0, + "content": "[26] Song Wang, Jianke Zhu, and Ruixiang Zhang. Metarangeseg: Lidar sequence semantic segmentation using multiple feature aggregation. IEEE Robotics and Automation Letters, 7(4):9739-9746, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.263, + 0.469, + 0.344 + ], + "angle": 0, + "content": "[27] Pengchuan Xiao, Zhenlei Shao, Steven Hao, Zishuo Zhang, Xiaolin Chai, Judy Jiao, Zesong Li, Jian Wu, Kai Sun, Kun Jiang, et al. Pandaset: Advanced sensor suite dataset for autonomous driving. In 2021 IEEE International Intelligent Transportation Systems Conference (ITSC), pages 3095-3101. IEEE, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.347, + 0.469, + 0.416 + ], + "angle": 0, + "content": "[28] Chenfeng Xu, Bichen Wu, Zining Wang, Wei Zhan, Peter Vajda, Kurt Keutzer, and Masayoshi Tomizuka. Squeeze-segv3: Spatially-adaptive convolution for efficient pointcloud segmentation. In European Conference on Computer Vision, pages 1-19. Springer, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.418, + 0.469, + 0.486 + ], + "angle": 0, + "content": "[29] Jianyun Xu, Ruixiang Zhang, Jian Dou, Yushi Zhu, Jie Sun, and Shiliang Pu. Rpvnet: A deep and efficient range-point-voxel fusion network for lidar point cloud segmentation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 16024-16033, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.488, + 0.469, + 0.557 + ], + "angle": 0, + "content": "[30] Xu Yan, Jiantao Gao, Chaoda Zheng, Chao Zheng, Ruimao Zhang, Shuguang Cui, and Zhen Li. 2dpass: 2d priors assisted semantic segmentation on lidar point clouds. In European Conference on Computer Vision, pages 677-695. Springer, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.559, + 0.469, + 0.626 + ], + "angle": 0, + "content": "[31] Maosheng Ye, Shuangjie Xu, Tongyi Cao, and Qifeng Chen. Drinet: A dual-representation iterative learning network for point cloud segmentation. In Proceedings of the IEEE/CVF international conference on computer vision, pages 7447-7456, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.629, + 0.469, + 0.711 + ], + "angle": 0, + "content": "[32] Yang Zhang, Zixiang Zhou, Philip David, Xiangyu Yue, Zerong Xi, Boqing Gong, and Hassan Foroosh. Polarnet: An improved grid representation for online lidar point clouds semantic segmentation. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9601-9610, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.713, + 0.469, + 0.781 + ], + "angle": 0, + "content": "[33] Zixiang Zhou, Yang Zhang, and Hassan Foroosh. Panoptic-polarnet: Proposal-free lidar point cloud panoptic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13194-13203, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.784, + 0.469, + 0.865 + ], + "angle": 0, + "content": "[34] Xinge Zhu, Hui Zhou, Tai Wang, Fangzhou Hong, Yuexin Ma, Wei Li, Hongsheng Li, and Dahua Lin. Cylindrical and asymmetrical 3d convolution networks for lidar segmentation. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 9939-9948, 2021." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.865 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.488, + 0.946, + 0.511, + 0.956 + ], + "angle": 0, + "content": "754" + } + ] +] \ No newline at end of file diff --git a/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/9db8fa07-a91f-4043-9a71-b3d3e6b17388_origin.pdf b/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/9db8fa07-a91f-4043-9a71-b3d3e6b17388_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..ed06d88016ab36f701ff04ce025df4fcc3dfb0bd --- /dev/null +++ b/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/9db8fa07-a91f-4043-9a71-b3d3e6b17388_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c51a0ba2c851e52664057cc287bd863f7cfb17e5187807233354b496dfe93eb3 +size 5092249 diff --git a/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/full.md b/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/full.md new file mode 100644 index 0000000000000000000000000000000000000000..116941f12fa4af8c86ed42ea08596c9d0b82e0cb --- /dev/null +++ b/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/full.md @@ -0,0 +1,247 @@ +# MemorySeg: Online LiDAR Semantic Segmentation with a Latent Memory + +Enxu Li Sergio Casas Raquel Urtasun Waabi University of Toronto {tli, sergio, urtasun}@waabi.ai + +# Abstract + +Semantic segmentation of LiDAR point clouds has been widely studied in recent years, with most existing methods focusing on tackling this task using a single scan of the environment. However, leveraging the temporal stream of observations can provide very rich contextual information on regions of the scene with poor visibility (e.g., occlusions) or sparse observations (e.g., at long range), and can help reduce redundant computation frame after frame. In this paper, we tackle the challenge of exploiting the information from the past frames to improve the predictions of the current frame in an online fashion. To address this challenge, we propose a novel framework for semantic segmentation of a temporal sequence of LiDAR point clouds that utilizes a memory network to store, update and retrieve past information. Our framework also includes a novel regularizer that penalizes prediction variations in the neighborhood of the point cloud. Prior works have attempted to incorporate memory in range view representations for semantic segmentation, but these methods fail to handle occlusions and the range view representation of the scene changes drastically as agents nearby move. Our proposed framework overcomes these limitations by building a sparse 3D latent representation of the surroundings. We evaluate our method on SemanticKITTI, nuScenes, and PandaSet. Our experiments demonstrate the effectiveness of the proposed framework compared to the state-of-the-art. For more information, visit the project website: https://waabi.ai/research/memoryseg. + +# 1. Introduction + +Semantic segmentation of LiDAR point clouds is a key component for the safe deployment of self-driving vehicles (SDV). It enables SDVs to enhance their understanding of the surrounding environment by categorizing every 3D point into specific classes of interest, such as vehicles, pedestrians, traffic signs, buildings, roadways, etc. This rich and precise 3D representation of the environment can then be used for various applications such as generating online or + +![](images/5bb242696325f5413353a18ba9d10318de2d8beb984d13165a23469698b2feb8.jpg) +Figure 1. Objects could be partially occluded in single frame LiDAR point cloud. Our approach learns a 3D latent memory representation for better contextualizing the online observations. We apply PCA [14] to reduce the latent dimension to 3 and plot as RGB. (Best viewed in color and zoomed-in.) + +![](images/117f91f4cb516d038ac16fc603a00cf7e95bcd53d2648f90be1a404ab033d4e8.jpg) + +offline semantic maps, building localization priors, or making the shapes of an object tracker more precise. + +LiDAR data is typically captured as a continuous stream of data, where every fraction of a second (typically 100ms) a new point cloud is available. Despite this fact, most LiDAR segmentation approaches process each frame independently [15, 32, 28, 22, 34, 5, 29] due to the computational and memory complexity associated with processing large amounts of 3D point cloud data. However, reasoning about a single frame suffers from the sparsity of the observations, particularly at range, and has difficulty handling occluded objects. Furthermore, the absence of motion information can make categorizing certain objects difficult. + +Several approaches [20, 19] utilize a sliding window approach, where a small set of past frames is processed independently at every time step. The main shortcoming of this approach is its limited temporal context (typically under 1 second) due to resource constraints, as processing multiple LiDAR scans at once is expensive. TemporalLidarSeg [8] proposed to utilize a latent spatial memory to retain information about the past while avoiding redundant computation every time a new scan is available, in a range view (RV) representation. However, the RV of the scene changes drastically as the SDV or the other actors move due to changes in perspective. As a result, the memory can be dominated by nearby objects, which appear larger in the RV representen + +tation, making it challenging to be updated from frame to frame. Occlusion can be particularly challenging as the occluder now occupies the same spatial region that was previously describing the occluded object. This limits the usefulness of the memory. In contrast to RV, 3D is a metric space where the distances between points are preserved regardless of the viewpoint or relative distance to the SDV. Thus, representing the memory in 3D enables learning size priors for different classes. It allocates equal representation power to them regardless of the distance to the SDV, and enables easy understanding of motion. Moreover, previously observed regions that are currently occluded can be remembered in the memory as the occluder and occluded objects occupy different 3D regions, even though they share the same space in RV. Despite these advantages, 3D memory has been overlooked in LiDAR semantic segmentation. + +In this paper we propose MEMORYSEG, a novel online LiDAR segmentation model that recurrently updates a sparse 3D latent memory as new observations are received, efficiently and effectively accumulating evidence from past observations. Fig. 1 illustrates the expressive power of such memory. In a single scan, objects are hard to identify due to sparsity (particularly at range) and lack of semantics, and occluded areas have no observations. In contrast, our latent memory is much denser, providing a rich context to separate different classes, especially in currently occluded regions. + +To achieve an effective memory update that takes into account both the past and the present for accurate decoding, our method addresses several challenges. First, we align the previous memory with the current observation in the latest ego frame, to compensate for the SDV motion. Second, the sparsity level of the memory and the observation embeddings are different, making fusion non-trivial. The latent memory is denser, and thus some currently unobserved locations may be present in the memory. Complementarily, some regions in the current scan have not been observed before, such as new observations appearing as the SDV drives further. For this reason, we propose a mechanism to fill in missing regions in the current observations and add new observations to the memory during the update. Third, other objects are also moving (potentially in opposite direction), thus fusing the memory and observation embeddings requires a large receptive field. We address this via a carefully designed architecture that achieves a large receptive field yet preserves sparsity for efficiency. Additionally, we introduce a novel point-level neighbourhood variation regularizer which penalizes significant differences in semantic predictions within local 3D neighborhoods. + +Extensive experiments in SemanticKITTI [2], nuScenes [4] and PandaSet [27] demonstrate that MEMORYSEG outperforms current state-of-the-art semantic segmentation methods that rely purely on LiDAR on multiple benchmarks. + +# 2. Related Work + +In this section, we start by reviewing LiDAR semantic segmentation approaches in the literature and then focus on methods proposed for temporal LiDAR reasoning. + +# 2.1. LiDAR Semantic Segmentation + +LiDAR-based semantic segmentation methods can be classified into four categories based on the type of data being processed: point-based [16, 17, 13, 24], projection-based [28, 7, 32], voxel-based [5, 34, 12], or a combination of the data representations [22, 29]. + +Point-based approaches [16, 17, 13, 24] operate directly on the point cloud, but most [17, 13, 24] rely on down-sampling to accommodate limited computational resources. KPCov [24] introduces customized spatial kernel-based point convolution which yields the most favorable outcomes compared to other point-based methods. However, it requires a significant amount of computational resources, which can limit its practicality in certain applications. + +Projection-based methods [28, 7, 32] involve projecting a 3D point cloud onto a 2D image plane, which can be done using either in spherical Range-View [28, 7], BirdEye-View [32], or multi-view representations [11]. These approaches usually operate in real-time, benefiting from efficient 2D CNN inference on GPUs. However, they suffer from significant information loss due to projection, which can prevent them from being on par with state-of-the-art methods. + +The emergence of 3D voxel-based approaches [5, 34, 12] can be attributed to recent advancements in sparse 3D convolutions [6, 21]. Typically, LiDAR point clouds are converted into Cartesian [5] or Cylindrical [34] voxels and then processed using sparse convolutions. They have demonstrated state-of-the-art performance, but reducing voxel resolution can result in significant loss of information. + +Recently, researchers have explored the potential of leveraging multiple data representations [22, 30, 29, 31] to benefit from the information acquired by each representation. For instance, SPVNAS [22] incorporates both pointwise features and 3D-voxel features in their network while learning to segment. Similarly, RPVNet [29] utilizes a trilateral structure in their network, where each branch adopts a distinct data representation mentioned earlier. + +Our method takes a similar approach to incorporate both point and voxel representations in the network. Voxel representations are utilized for contextual information learning, while point representations are employed to preserve fine-grained details, such as object boundaries and curvatures. + +# 2.2. Temporal LiDAR Reasoning + +Previous methods [20, 19, 26] have attempted to integrate a small number of past frames to facilitate temporal + +reasoning. For instance, SpSequenceNet [20] introduces cross-frame global attention, which uses information from the previous frame to emphasize features in the current frame. Additionally, it utilizes cross-frame local interpolation to combine local features from both the previous and current frame. Further, MetaRangeSeg [26] includes information from past frames by having the residual depth map as an additional feature to the input. However, these methods are not well-suited for continuous application to a temporal sequence of LiDAR point clouds. Firstly, they are inefficient as they discard previous observations and require the model to start from scratch each time a new point cloud is received. Secondly, they only aggregate temporal information within a short horizon, failing to capture the potential of temporal reasoning over a longer duration. + +Several works [8, 9] have attempted to incorporate temporal reasoning through a recurrent framework. Specifically, Duerr et al. [8] presents a recurrent segmentation architecture in RV, which uses previous observations as memory and aligns them temporally in the range image space. However, RV memory has limitations, such as prioritizing nearby objects, and suffering from contention of memory resources during occlusions (since information from behind the occluder and the occluder itself are now sharing the same memory entries). Further, StrObe [9] implemented a multi-scale 2D BEV memory for object detection enabling the network to take advantage of previous computations and process new LiDAR data incrementally. However, compared to object detection, semantic segmentation requires a more fine-grained and nuanced understanding of the scene and therefore a 3D memory is more suitable than 2D BEV. + +Our approach is distinct from previous methods as we propose an online LiDAR semantic segmentation framework utilizing a sparse 3D memory. By representing the memory in 3D, we preserve the distance between points regardless of viewpoint or distance from the SDV, allowing for size priors of different classes to be learned. Additionally, the memory also retains previously observed regions even when currently occluded, as occluders and occluded objects occupy different 3D regions, despite being in the same space in RV. Furthermore, we preserve fine-grained height details that are lost in the BEV memory. + +# 3.3D Memory-based LiDAR Segmentation + +In this section we introduce MEMORYSEG, an online semantic segmentation framework for streaming LiDAR point clouds that leverages a 3D latent memory to remember the past and better handle occlusions and sparse observations. In the remainder of this section, we first describe our model formulation, then present the network architecture and finally explain the learning process. + +# 3.1. Model Formulation + +Let $\mathcal{P} = \{\mathcal{P}_t\}_{t=1}^L$ be a sequence of LiDAR sweeps where $L \in \mathbb{N}^+$ is the sequence length and $t \in [1, L]$ is the time index. Each LiDAR sweep $\mathcal{P}_t = (\mathbf{G}_t, \mathbf{F}_t)$ is a $360^\circ$ scan of the surrounding with $N_t$ unordered points. $\mathbf{G}_t \in \mathbb{R}^{N_t \times 3}$ contains the Cartesian coordinates in the ego vehicle frame and $\mathbf{F}_t \in \mathbb{R}^{N_t}$ is the LiDAR intensity of the point. Let $\mathbf{T}_{t-1 \to t} \in SE(3)$ be the pose transformation from the vehicle frame at time $t-1$ to $t$ . + +To make informed semantic predictions, in this paper we maintain a latent (or hidden) memory in 3D. This memory is sparse in nature since the majority of the 3D space is unoccupied. To represent this sparsity, we parametrize the memory at time $t$ using a sparse set of voxels containing the coordinates $H_{G,t} \in \mathbb{R}^{M_t \times 3}$ and their corresponding learned embeddings $H_{F,t} \in \mathbb{R}^{M_t \times d_m}$ . $M_t$ is the number of voxel entries in the latent memory at time $t$ and $d_m$ is the embedding dimension. Preserving the voxel coordinates is important to perform alignment as the reference changes when the SDV moves. We utilize a voxel-based sparse representation as it provides notable computational benefits with respect to dense tensors as well as sparse representations at the point level without sacrificing performance. + +Inference follows a three-step process that is repeated every time a new LiDAR sweep is available: (i) the encoder takes in the most recent LiDAR point cloud at current time $t$ and extracts point-level and voxel-level observation embeddings, (ii) the latent memory is updated taking into account the voxel-level embeddings from the new observations, and (iii) the semantic predictions are decoded by combining the point-level embeddings from the encoder and voxel-level embeddings from the updated memory. We refer the reader to Fig. 2 for an illustration of our method. + +The memory update stage faces challenges due to the changing reference frame as the SDV moves, different sparsity levels of memory and current LiDAR sweep, as well as the motion of other actors. To address these challenges, a Feature Alignment Module (FAM) is introduced to align the previous memory state with the current observation embeddings. Subsequently, an Adaptive Padding Module (APM) is utilized to fill in missing observations in the current data and add new observations to the memory. Then, a Memory Refinement Module (MRM) is employed to update the latent memory using padded observations. Next, we explain each component in more detail. + +Encoder: Following [22], our encoder is composed of a point-branch that computes point-level embeddings preserving the fine details and a voxel-branch that performs contextual reasoning through 3D sparse convolutional blocks [21]. The point-branch receives a 7-dimensional feature vector per point, with the xyz coordinates, intensity, and relative offsets to the nearest voxel center as features. It comprises two shared MLPs that output point embeddings, + +![](images/dd010bd514f353a03c675e261fa2550d17534abb629a6c20ad5802aa64f0b154.jpg) +Figure 2. An overview of our model, MEMORYSEG. After the encoder processes the LiDAR point cloud at time $t$ , the resulting feature map is utilized to update the latent memory (see Fig. 3 for more details about the memory update). Then, the decoder combines the refined memory with the point embeddings from the encoder to obtain semantic predictions. + +![](images/eb7a6e4abb0d0d94406f0da981144bf80ef8d0201ed05dc3925138e3d8049b63.jpg) +Figure 3. Overview of the latent memory update process. The latent memory embeddings $(H_{G,t - 1},H_{F,t - 1})$ are transformed to the ego frame at $t$ with the Feature Alignment Module (FAM). Next, the Adaptive Padding Module (APM) is utilized to learn the padding of both memory and observation embeddings. The Memory Refinement Module (MRM) updates the latent memory by incorporating the padded observation embeddings. The updated memory is then passed to the decoder for generating semantic predictions. (Best viewed in color and zoomed-in.) + +as illustrated in Fig. 2. We average point embeddings belonging to the same voxel from the first shared MLP over voxels of size $v_{b}$ to obtain voxel features. These features are then processed through four residual blocks with 3D sparse convolutions, each downsampling the feature map by a factor of 2. Two additional residual blocks with 3D sparse convolutions are applied to upsample the sparse feature maps. Unlike a full U-Net [18] that recovers features at the original resolution, we only upsample to $\frac{1}{4}$ of the original size for computational efficiency reasons, and use the coarser features to update the latent memory before decoding finer details to output our semantic predictions. + +Feature Alignment: The reference frame changes as the SDV moves. We propose the Feature Alignment Module (FAM) to transform the latent memory from the ego frame at $t - 1$ to $t$ and align with the current observation embeddings. Specifically, we take the memory voxel coordinates $H_{G,t-1}$ and use the pose information $\mathbf{T}_{t-1 \to t}$ to project from the ego frame at $t - 1$ to $t$ . We then re-voxelize using the projected coordinates with a voxel size of $v_m$ . If multiple entries are inside the same memory voxel, we take the average of them to be the voxel feature. The resulting warped coordinates and embeddings of the memory in the + +ego frame $t$ are denoted as $\tilde{H}_{G,t}$ and $\tilde{H}_{F,t}$ , respectively. + +Adaptive Padding: To handle the different sparsity of the latent memory and the voxel-level observation embeddings, we propose the Adaptive Padding Module (APM). We refer the readers to Fig. 3 for an illustration. First, we re-voxelize the encoder features with the same voxel size $v_{m}$ where entries within the same voxel are averaged. We denote the resulting coordinates and embeddings as $X_{G}$ and $X_{F}$ . Note that we omit $t$ in this section for brevity. Let $x_{G} \subseteq X_{G}$ and $x_{F} \subseteq X_{F}$ be the coordinates and embeddings of the new observations at time $t$ that are not present in the memory. To obtain an initial guess of the memory embedding for a new entry, we utilize a weighted aggregation approach within its surrounding neighbourhood. This involves taking into account the coordinate offsets relative to the existing neighbouring voxels in the memory, which provides insight into their importance for aggregation, similar to Continuous Conv [25]. In addition to this, we incorporate the feature similarities and feature distances as additional cues for the aggregation process. Encoding feature similarities is particularly useful for assigning weights to the neighborhood. In a dynamic scene with moving actors, the closest voxel may not always be the most important voxel. By providing feature similarities, the network can make more informed decisions. The goal of such completion is to make a hypothesis of the embedding at the previously unobserved location using the available information. More precisely, we add those entries in the memory where their coordinates are $h_{G}^{\prime} = x_{G}$ and the embedding of each voxel $j$ are initialized as follows, + +$$ +h _ {F, j} ^ {\prime} = \sum_ {i \in \Omega_ {\tilde {H}} (j)} w _ {j i} \tilde {H} _ {F, i}, \tag {1} +$$ + +$$ +w _ {j i} = \psi \left(\tilde {H} _ {G, i} - x _ {G, j}, \| \tilde {H} _ {F, i} - x _ {F, j} \|, \frac {\tilde {H} _ {F , i} \cdot x _ {F , j}}{\| \tilde {H} _ {F , i} \| \| x _ {F , j} \|}\right), \tag {2} +$$ + +where $i$ and $j$ are voxel indices, $\Omega_{\tilde{H}}(j)$ is the k-nearest-neighborhood of voxel $j$ in $\tilde{H}_G$ , and $\psi$ is a shared MLP + +followed by a softmax layer on the dimension of neighbourhood to ensure $\sum_{i}w_{ji} = 1$ + +Second, we identify the regions in the memory that are unseen in the current observation and denote their coordinates and embeddings as $\tilde{h}_G \subseteq \tilde{H}_G$ and $\tilde{h}_F \subseteq \tilde{H}_F$ . We add entries $x_G'$ and $x_F'$ to complete the current observation in a similar manner. + +Memory Refinement: We design a sparse version of a ConvGRU [1] to update the latent memory $H_{F,t-1}^{\prime}$ using the current padded observation embeddings $X_{F,t}^{\prime}$ as follows: + +$$ +\begin{array}{l} r _ {t} = \operatorname {s i g m o i d} \left[ \Psi_ {r} \left(X _ {F, t} ^ {\prime}, H _ {F, t - 1} ^ {\prime}\right) \right], \\ z _ {t} = \operatorname {s i g m o i d} \left[ \Psi_ {z} \left(X _ {F, t} ^ {\prime}, H _ {F, t - 1} ^ {\prime}\right) \right], \\ \hat {H} _ {F, t} = \tanh \left[ \Psi_ {u} \left(X _ {F, t} ^ {\prime}, r _ {t} \cdot H _ {F, t - 1} ^ {\prime}\right) \right], \tag {3} \\ H _ {F, t} = \hat {H} _ {F, t} \cdot z _ {t} + H _ {F, t - 1} ^ {\prime} \cdot (1 - z _ {t}), \\ \end{array} +$$ + +where $\Psi_r, \Psi_z, \Psi_u$ are sparse 3D convolutional blocks with downsampling layers that aim to expand the receptive field and upsampling layers that restore the embeddings to their original size. $r_t$ and $z_t$ are learned signals to reset or update the memory, respectively. We refer the readers to the supplementary material about the detailed architecture of the sparse convolutional blocks. + +Decoder: Our decoder consists of an MLP, two residual blocks with sparse 3D convolutions, and a linear semantic header. Specifically, we first take the corresponding memory embeddings at coordinates $\mathbf{G}_t$ and add with the point embeddings from the encoder. The resulting combined embeddings are then voxelized with voxel size of $\frac{v_b}{4}$ and further processed by two residual blocks that upsample the feature maps back to the original resolution. In parallel, an MLP takes the point embeddings before voxelization to retain the fine-grained details. Finally, the semantic header takes the combination of voxel and point embeddings to obtain per-point semantic predictions. + +Memory Initialization: At the start of the sequence ( $t = 0$ ), the first observation is used to initialize memory, with $H_{G,0} = X_{G,0}$ and $H_{F,0} = X_{F,0}$ . + +# 3.2. Learning + +We learn our segmentation model by minimizing a linear combination of conventional segmentation loss functions [13, 34, 22] and a novel point-wise regularizer to better supervise the network training. + +$$ +J = \beta_ {w c e} J _ {w c e} + \beta_ {l s} J _ {l s} + \beta_ {r e g} J _ {r e g}. \tag {4} +$$ + +Here, $J_{wce}$ denotes cross-entropy loss, weighted by the inverse frequency of classes, to address class imbalance in the dataset. The Lovasz Softmax Loss ( $J_{ls}$ ) [3] is used to train the network, as it is a differentiable surrogate for the non-convex intersection over union (IoU) metric, which is + +a commonly used evaluation metric for semantic segmentation. Additionally, $J_{reg}$ corresponds to our proposed pointwise regularizer. $\beta_{reg}, \beta_{wce}$ and $\beta_{ls}$ are hyperparameters. + +Point-wise Smoothness: Our regularizer is designed to limit significant variations in semantic predictions within the 3D neighborhood of each point, except when these variations occur at the class boundary. Formally, + +$$ +\begin{array}{l} J _ {r e g} = \frac {1}{N _ {t}} \sum_ {\substack {i = 1 \\ 1}} ^ {N _ {t}} | \Delta (Y, i) - \Delta (\hat {Y}, i) |, \tag{5} \\ \Delta (Y, i) = \Big | \frac {1}{| \Omega_ {\mathcal {P} _ {t}} (i) |} \sum_ {j \in \Omega_ {\mathcal {P} _ {t}} (i)} | y _ {i} - y _ {j} | \Big |. \\ \end{array} +$$ + +Here, $\Delta(Y, i)$ represents the ground truth semantic variation around point $i$ , while $\Delta(\hat{Y}, i)$ corresponds to the predicted semantic variation around point $i$ . We use $\hat{Y} \in \mathbb{R}^{N_t \times C}$ to denote the predicted semantic distribution over $C$ classes, and $Y \in \mathbb{R}^{N_t \times C}$ to denote the ground truth semantic one-hot label. The variable $y_i$ represents the $i$ -th element of $Y$ . $\Omega_{\mathcal{P}_t}(i)$ denotes the neighborhood of point $i$ in $\mathcal{P}_t$ , and $|\Omega_{\mathcal{P}_t}(i)|$ represents the number of points in the neighborhood. The inspiration for this regularizer comes from a study by [11] that penalizes adjacent pixel prediction variations with the ground truth. + +# 4. Experiments + +In this section, we thoroughly analyze the performance of our method on three different datasets: SemanticKITTI [2], nuScenes [4], and PandaSet [27]. These datasets were collected using different LiDAR sensors and in diverse geographical regions. Our results demonstrate that MEMORY-SEG outperforms the current state of the art in all benchmarks. Additionally, we conduct ablation studies to understand the impact of our contributions. We demonstrate that incorporating a 3D sparse latent memory improves semantic predictions, with a very significant gain in long-range areas as these are sparser and more often partially obstructed than short-range regions. + +Datasets: We benchmark our approach on three large-scale autonomous driving datasets: SemanticKITTI [2] consists of 22 sequences from the KITTI Odometry Dataset [10], which was collected in Germany using a Velodyne HDL-64E LiDAR. We use the standard split where sequences 0 to 10 are used for training (with sequence 8 for validation), and sequences 11 to 21 are held for testing. We follow the standard setting where semantic labels are mapped to 19 classes for the single-scan benchmark and 25 for the multi-scan benchmark. In the latter, all movable classes are further divided into moving and non-moving classes. Given that prior research on temporal aggregation for semantic segmentation is more prevalent in + +
MethodmIoUCarBicycleMoonecycleTruckOther VehiclePersonBicyclistMoonecyclistRoadParkingSidewalkOther GroundBuildingFenceVegetationTrunkTerrainPoleTraffic Signcar (m)bicyclist (m)person (m)motorcycle (m)other-vehicle (m)truck (m)
TangentConv [23]34.184.92.018.221.118.51.60.00.083.938.364.015.385.849.179.543.256.736.431.240.31.16.41.930.142.2
DarkNet53Seg [2]41.684.130.432.920.220.77.50.00.091.664.975.327.585.256.578.450.764.838.153.361.514.115.20.228.937.8
KPConv [24]51.293.744.947.242.538.621.60.00.086.558.470.526.790.864.584.670.366.057.053.969.467.467.547.24.75.8
Cylinder3D [34]52.594.667.663.841.338.812.51.70.290.765.074.532.392.666.085.872.068.963.161.474.968.365.711.90.10.0
SpSequenceNet [20]43.188.524.026.229.222.76.30.00.090.157.673.927.191.266.884.066.065.750.848.753.241.226.236.22.30.1
TemporalLidarSeg [8]47.092.147.740.939.235.014.40.00.091.859.675.823.289.863.882.362.564.752.660.468.242.840.412.912.42.1
TemporalLatticeNet [19]47.191.635.436.126.923.09.40.00.091.559.375.327.589.665.384.666.770.457.260.459.741.751.048.85.90.0
Meta-RangeSeg [26]49.790.850.049.529.534.816.60.00.090.862.974.826.589.862.182.865.766.556.264.569.060.457.922.016.62.6
MEMORYSEG [ours]58.394.068.368.851.340.927.00.32.889.964.374.829.292.269.384.875.170.165.568.571.774.471.773.915.113.6
+ +Table 1. Comparison to the state-of-the-art methods on the test set of SemanticKITTI [2] multi-scan benchmark. (m) indicates moving. We include LiDAR-only published approaches at the time of submission. These approaches are categorized into two groups: the first group includes methods that aim for single-scan segmentation but use multiple aggregated frames as input; the second group consists of methods that introduce temporal aggregation modules explicitly tailored for handling multiple scans. Metrics are provided in [%]. + +the multi-scan benchmark, we consider it more appropriate for evaluating our proposed method. Single-scan benchmark results are also provided in the supplementary material. nuScenes [4] was collected in Boston and Singapore using a Velodyne HDL-32E LiDAR sensor, which captures sparser point clouds that pose extra challenges for semantic reasoning. The dataset contains a total of 1000 scenes, with 700 scenes used for training, 150 for validation, and the remaining 150 held out for testing. Each scene contains about 40 labeled frames recorded at $2\mathrm{Hz}$ . We follow the standard setting which maps 31 fine-grained classes to 16 classes for training and evaluation. PandaSet [27] provides short sequences of temporal data but with a large number of moving actors in Silicon Valley. This dataset was collected using a Hesai-Pandar64 LiDAR and consists of 103 sequences, each with a length of 8 seconds. Following [8], we grouped the original fine-grained semantic classes into 14 for training and testing, trying to match the classes in other popular segmentation benchmarks [2, 4]. We also used the same train/Validation/test split as in the reference paper. + +Implementation details: For all datasets, we first train the network without the memory update for single-scan segmentation for 50 epochs. Then, we freeze the encoder and train the memory update block and decoder in a recurrent fashion for an additional 20 epochs. During each training iteration, we use the first 10 consecutive sweeps as warmup memory, and then train the network with backpropagation through time (BPTT) on the next 3 frames. The memory voxel size $v_{m}$ is $0.5\mathrm{m}$ , and the embedding dimension $d_{m}$ is 128. We use the AdamW optimizer with a starting learning rate of 0.003 and a decay factor of 0.9. During training, we use data augmentation including global scaling sampled at random from [0.80, 1.20], translation sampled from [0, 0.2] m on all three axes, and global rotation around the Z axis with a random angle sampled from $[-\pi ,\pi ]$ . We set the loss weights $\beta_{wce}$ to 1, $\beta_{ls}$ to 2, and $\beta_{reg}$ to 500. We set the regularizer neighborhood $\Omega_{P_t}(i)$ to be the closest 32 points around point $i$ , and use a padding neighbourhood $\Omega_{\tilde{H}}(j)$ to be the closest 5 voxels of voxel $j$ . All experiments are conducted using 4 NVIDIA T4 GPUs with a batch size of 1 per GPU. During evaluation, we unroll each sequence from the + +first frame to the end and follow [34, 12] to apply test-time-augmentation, i.e. averaging prediction scores of 10 forward passes with augmented input from a single model. + +To adapt to the uniqueness of each dataset, we consider the following per-dataset settings. To train on the SemanticKITTI dataset, we set the voxel size $v_{b}$ to 0.05 m. Due to the limited quantities of movable actors in this dataset, following [33] we generate a library of instances from the training sequences and randomly inject 5 objects over the ground classes at each frame during training. To improve the ability to separate classes into moving and non-moving actors, we add another linear header to classify points as moving or static and fuse the results from the semantic header. More implementation details are provided in the supplementary material. For nuScenes, the voxel size is set to 0.1 m, and 0.125 m for PandaSet. + +Metrics: We follow existing works [34, 5, 29] and use the intersection over union (IoU) averaged over all classes as the main metric (mIoU). Class-wise IoUs are also reported. Comparison against state-of-the-art: Our results are compared with other state-of-the-art approaches on the test set of three datasets in Tab. 1 to 3. We include approaches that use LiDAR only for fair comparison. Notably, our proposed method outperforms all prior works on all three datasets, demonstrating its generalizability across various LiDAR sensors and different geographical regions. + +Tab. 1 presents a comparison of our approach on the SemanticKITTI multi-scan benchmark, which is designed to evaluate methods that focus on temporal aggregation for semantic segmentation. The other methods in the table are divided into two groups. The first group consists of baselines that are designed for single-scan segmentation but aggregate multiple consecutive frames as input at the cost of higher memory consumption and longer runtime. In contrast, the second group proposes temporal aggregation modules specifically to handle multiple scans. It is worth noting that our proposed method performs significantly better than all of these approaches. MEMORYSEG demonstrates exceptional performance in segmenting dynamic actors, such as moving bicyclist, motorcyclist, and person. These substantial improvements can be attributed to the proposed re + +
MethodmIoUFW-mIoUBarrierBicycleBusCarConstructionMotorcyclePedestrainTraffic ConeTrailerTruckDrivableOther FlatSidewalkTerrainMannmadeVegetation
PolarNet [32]69.487.472.216.877.086.551.169.764.854.169.763.596.667.177.772.187.184.5
Cylinder3D [34]77.289.982.829.884.389.463.079.377.273.484.669.197.770.280.375.590.487.6
SPVCNN [22]77.489.780.030.091.990.864.779.075.670.981.074.697.469.280.076.189.387.1
(AF)2-S3Net [5]78.388.578.952.289.984.277.474.377.372.083.973.897.166.577.574.087.786.8
MEMORYSEG [ours]80.691.484.940.291.292.471.273.585.977.888.076.497.969.081.277.692.689.7
+ +Table 2. Comparison to the state-of-the-art methods on the test set of nuScenes [4] LiDAR semantic segmentation benchmark. We include LiDAR-only published approaches at the time of submission. Metrics are provided in [%] + +
MethodmIoUCarBicycleMotorcycleTruckOther VehiclePersonRoadRoad BarriersSidewalkBuildingVegetationTerrainBackgroundTraffic Sign
SqueezeSegv3 [28]55.792.824.118.036.554.363.091.111.971.386.285.061.363.220.6
SalsaNext [7]57.892.140.731.728.756.269.090.022.667.185.683.458.563.320.6
TemporalLidarSeg [8]60.093.733.638.037.159.972.091.114.670.688.288.463.868.420.7
SPVCNN [22]64.795.838.146.344.074.178.691.228.370.387.287.561.567.535.6
MEMORYSEG [ours]70.397.260.258.462.974.382.692.127.774.189.490.764.972.836.4
+ +Table 3. Comparison to the state-of-the-art methods on the test set of PandaSet [27]. Metrics are provided in [%]. + +current framework, which implicitly encode the motion of moving actors in the 3D latent memory. Furthermore, we also demonstrate the effectiveness of our approach on the single-scan benchmark of the same dataset. We refer the readers to the supplementary material for the detailed results. This is a more competitive benchmark focusing on single-scan semantic segmentation where previous research has focused on proposing various architectures [5, 29, 34] or knowledge distillation techniques [12]. Our results show that MEMORYSEG can outperform these methods, which are highly optimized for this benchmark. + +Results on nuScenes [4] benchmark are presented in Tab. 2. MEMORYSEG outperforms the previous state-of-the-art. Our method is particularly effective in smaller classes such as barriers, pedestrians, and traffic cones, which present challenges for semantic segmentation networks due to the sparser point clouds available in this dataset. However, our approach overcomes this limitation by using a 3D latent memory to improve semantic reasoning of the sparse points. Additionally, we observe significant gains in the background classes, such as sidewalk, terrain, and manmade, which often rely on understanding of the surrounding to be segmented correctly. Our method improves the contextual reasoning by accumulating past observations using a latent memory representation. + +Finally, we compare our results with the state-of-the-art methods on PandaSet [27] and report the test set IoUs in Tab. 3. Our proposed method also achieves state-of-the-art performance in this dataset. Notably, our approach outperforms others by a large margin in almost all classes. We highlight that MEMORYSEG consistently outperforms TemporalLidarSeg [8] across multiple benchmarks, a method that also proposes a latent memory but in RV instead of 3D. These findings confirm our hypothesis that the 3D latent memory approach is more effective than using RV in + +accurately segmenting objects in 3D point clouds. + +Importance of the memory: Fig. 4 highlights the significance of incorporating memory, particularly in longer range regions where point clouds are much sparser. To assess the effectiveness of the learned latent memory, we compare against our encoder and decoder without the memory update module as the single frame baseline (SFB). Our proposed network consistently outperforms the SFB in all regions, with the most significant improvement observed in the long-range region of nuScenes, where points are sparser and more difficult to contextualize. Thanks to the 3D sparse latent memory that accumulates semantic embeddings of past frames, our proposed approach performs much better than the SFB, particularly in those challenging regions. Fig. 5 provides similar insights. In the top-left of the figure, the SFB fails to segment a partially occluded vehicle located behind a fence. In contrast, our proposed approach initially segments the vehicle as other vehicle class, but as the ego vehicle advances, the 3D latent memory accumulates and refines through new observations, enabling the network to correctly identify the vehicle as a car after two sweeps. This illustration further confirms that the proposed 3D latent memory provides better contextualization of sparse objects that are partially occluded. Additional qualitative results are provided in the supplementary materials. We also quantitatively demonstrate the importance of memory in Tab. 4. M1 builds on SFB and incorporates FAM and MRM. Note that both FAM and MRM are essential for updating the latent memory continuously. FAM aligns the sparse 3D latent memory in the traveling ego frame, while MRM helps in learning to reset and update the memory recurrently. APM is replaced with zero-padding in M1 to highlight the significance of memory. M1 shows a $2.3\%$ improvement in the mIoU metric compared to SFB, attributed to the ability of the sparse 3D latent memory to aggregate information in the + +![](images/c348a92562f83dc6f81a722b53334aa51d91ac4d8133d3b32cbc9ff1f36538cf.jpg) +Figure 4. Comparison of MEMORYSEG with single frame baseline (SFB) on the validation set with different distance-range. + +![](images/16a254d4d06ebc9e4d62b15bcb503d1ffa68b8f04d1226febbd8f6da7be64b03.jpg) + +![](images/a9b38dbbd4ac12da2f32f0361b8bf1bc03c879777c81cefdd4f2d2537f42021d.jpg) + +![](images/c36b96394e07a95ad5a8dc2679eb6408d10ed23e71334877732f3c8e4fe54fd7.jpg) +Figure 5. Predictions of MEMORYSEG over time are illustrated in the bottom row. We include the prediction from the single frame baseline (SFB) and ground truth with color code at the top. + +temporal dimension as the ego moves through the scene. + +Influence of adaptive padding: In this section, we compare our proposed APM with zero padding and Continuous Conv [25]. The results are presented in Tab. 4. M2 is an extension of M1 that introduces adaptive padding on both observation and memory embeddings when they are aligned. However, the padded entries are only processed using the relative coordinates in the neighborhood, similar to Continuous Conv [25] with the attention mechanism. A slight improvement of $0.2\%$ is observed when new observations in the latent memory are initialized with a learned guess instead of all zeros. To further improve the performance of the network, M4 exploits feature similarities and distances in APM. When assigning an initial embedding to a new entry, both the relative position and the similarity to neighbors are considered. This is particularly useful for moving actors in the scene, where the network should learn to start with a guess with a similar embedding in the neighborhood, rather than the closest entry. By comparing M0 with M3 further confirms the usefulness of the proposed APM. + +Influence of memory refinement: In M3 of Tab. 4, we replace our proposed MRM with a vanilla sparse ConvGRU [1], which has a limited receptive field due to the convolution kernel size, making it challenging for fast-moving actors. However, MRM overcomes this limitation by down-sampling features to increase the receptive field. This improves the learning of meaningful reset and update gates for refining the latent memory. + +
FAMAPMMRMmIoU
CCOursSCGOurs
SFB67.2
M0✓✓✓68.9
M1✓✓69.5
M2✓✓✓69.7
M3✓✓✓69.7
M4✓✓✓70.8
+ +Table 4. Ablation on the proposed components in the network. Metrics are mIoU on the validation set of SemanticKITTI [2] provided in [%]. FAM: Feature Alignment Module, APM: Adaptive Padding Module, CC: padding using Continuous Conv [25], SCG: Sparse ConvGRU [1]. MRM: Memory Refinement Module. + +
RegularizerSemanticKITTInuScenesPandaSet
66.472.964.7
✓67.276.766.6
+ +Table 5. Ablation on the model performance with and without the proposed regularizer. Metrics are mIoU on the validation set provided in [%]. + +Influence of the regularizer: To demonstrate the effectiveness of our regularizer to train semantic segmentation networks on point clouds with different characteristics, we ablate this loss on the three datasets and summarize the results in Tab. 5. The results consistently show that incorporating the regularizer leads to performance improvements. The regularizer provides additional supervision on variations and boundaries, which is particularly beneficial for nuScenes. We note once again that this dataset has sparser point clouds than the other two. + +Parameter count and runtime comparison: MEMORY-SEG incurs only a relatively small computational overhead of $23\%$ more parameters and $20\%$ runtime than SFB. On the other hand, when naively concatenating the past five frames as the input to the model, despite having the same number of parameters as SFB, it takes 1.58 times longer (32% slower than our method) while only exploiting a limited 0.5-second window from the past. + +# 5. Conclusion + +In this paper, we have proposed a novel online LiDAR segmentation model named MEMORYSEG, which utilizes a sparse 3D latent memory to recurrently accumulate learned semantic embeddings from past observations. We also presented a novel variation regularizer to supervise the learning of 3D semantic segmentation on point clouds. Our results demonstrate that our approach achieve state-of-the-art performance on three large-scale datasets. This improved performance can be attributed to the ability of the latent memory to better contextualize objects in the scene. Looking ahead, our future work will focus on integrating instance segmentation and tracking to develop an end-to-end memory-augmented panoptic segmentation framework. + +# References + +[1] Nicolas Ballas, Li Yao, Chris Pal, and Aaron C. Courville. Delving deeper into convolutional networks for learning video representations. In 4th International Conference on Learning Representations, ICLR 2016, San Juan, Puerto Rico, May 2-4, 2016, Conference Track Proceedings, 2016. +[2] Jens Behley, Martin Garbade, Andres Milioto, Jan Quenzel, Sven Behnke, Cyril Stachniss, and Jürgen Gall. Semantickitti: A dataset for semantic scene understanding of lidar sequences. In 2019 IEEE/CVF International Conference on Computer Vision, pages 9296-9306. IEEE, 2019. +[3] Maxim Berman, Amal Rannen Triki, and Matthew B Blaschko. The lovasz-softmax loss: A tractable surrogate for the optimization of the intersection-over-union measure in neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4413-4421, 2018. +[4] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11621-11631, 2020. +[5] Ran Cheng, Ryan Razani, Ehsan Taghavi, Enxu Li, and Bingbing Liu. af2-s3net: Attentive feature fusion with adaptive feature selection for sparse semantic segmentation network. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 12547-12556, 2021. +[6] Christopher Choy, JunYoung Gwak, and Silvio Savarese. 4d spatio-temporal convnets: Minkowski convolutional neural networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 3075-3084, 2019. +[7] Tiago Cortinhal, George Tzelepis, and Eren Erdal Aksoy. Salsanext: Fast semantic segmentation of lidar point clouds for autonomous driving. In 2020 IEEE Intelligent Vehicles Symposium (IV), pages 655-661, 2020. +[8] Fabian Duerr, Mario Pfaller, Hendrik Weigel, and Jürgen Beyerer. Lidar-based recurrent 3d semantic segmentation with temporal memory alignment. In 2020 International Conference on 3D Vision (3DV), pages 781-790. IEEE, 2020. +[9] Davi Frossard, Shun Da Suo, Sergio Casas, James Tu, and Raquel Urtasun. Strobe: Streaming object detection from lidar packets. In Jens Kober, Fabio Ramos, and Claire Tomlin, editors, Proceedings of the 2020 Conference on Robot Learning, volume 155 of Proceedings of Machine Learning Research, pages 1174-1183. PMLR, 16-18 Nov 2021. +[10] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the kitti vision benchmark suite. In Conference on Computer Vision and Pattern Recognition (CVPR), 2012. +[11] Martin Gerdzhev, Ryan Razani, Ehsan Taghavi, and Liu Bingbing. Tornado-net: multiview total variation semantic segmentation with diamond inception module. In 2021 + +IEEE International Conference on Robotics and Automation (ICRA), pages 9543-9549, 2021. +[12] Yuenan Hou, Xinge Zhu, Yuexin Ma, Chen Change Loy, and Yikang Li. Point-to-voxel knowledge distillation for lidar semantic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8479-8488, 2022. +[13] Qingyong Hu, Bo Yang, Linhai Xie, Stefano Rosa, Yulan Guo, Zhihua Wang, Niki Trigoni, and Andrew Markham. Randla-net: Efficient semantic segmentation of large-scale point clouds. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 11108-11117, 2020. +[14] Ian Jolliffe. *Principal Component Analysis*. John Wiley & Sons, Ltd, 2005. +[15] Andres Milioto, Ignacio Vizzo, Jens Behley, and Cyril Stachniss. Rangenet++: Fast and accurate lidar semantic segmentation. In Proc. of the IEEE/RSJ Intl. Conf. on Intelligent Robots and Systems (IROS), 2019. +[16] Charles R Qi, Hao Su, Kaichun Mo, and Leonidas J Guibas. Pointnet: Deep learning on point sets for 3d classification and segmentation. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 652-660, 2017. +[17] Charles Ruizhongtai Qi, Li Yi, Hao Su, and Leonidas J Guibas. Pointnet++: Deep hierarchical feature learning on point sets in a metric space. Advances in neural information processing systems, 30, 2017. +[18] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In Medical Image Computing and Computer-Assisted Intervention-MICCAI 2015: 18th International Conference, Munich, Germany, October 5-9, 2015, Proceedings, Part III 18, pages 234-241. Springer, 2015. +[19] Peer Schütt, Radu Alexandru Rosu, and Sven Behnke. Abstract flow for temporal semantic segmentation on the permutohedral lattice. In Proceedings of the IEEE International Conference on Robotics and Automation (ICRA), 2022. +[20] Hanyu Shi, Guosheng Lin, Hao Wang, Tzu-Yi Hung, and Zhenhua Wang. Spsequencenet: Semantic segmentation network on 4d point clouds. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 4574-4583, 2020. +[21] Haotian Tang, Zhijian Liu, Xiuyu Li, Yujun Lin, and Song Han. Torchsparse: Efficient point cloud inference engine. Proceedings of Machine Learning and Systems, 4:302-315, 2022. +[22] Haotian Tang, Zhijian Liu, Shengyu Zhao, Yujun Lin, Ji Lin, Hanrui Wang, and Song Han. Searching efficient 3d architectures with sparse point-voxel convolution. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23–28, 2020, Proceedings, Part XXVIII, pages 685–702. Springer, 2020. +[23] Maxim Tatarchenko, Jaesik Park, Vladlen Koltun, and Qian-Yi Zhou. Tangent convolutions for dense prediction in 3d. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3887-3896, 2018. +[24] Hugues Thomas, Charles R Qi, Jean-Emmanuel Deschaud, Beatrix Marcotegui, François Goulette, and Leonidas J + +Guibas. Kpconv: Flexible and deformable convolution for point clouds. In Proc. of the IEEE International Conference on Computer Vision, pages 6411-6420, 2019. +[25] Shenlong Wang, Simon Suo, Wei-Chiu Ma, Andrei Pokrovsky, and Raquel Urtasun. Deep parametric continuous convolutional neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2589-2597, 2018. +[26] Song Wang, Jianke Zhu, and Ruixiang Zhang. Metarangeseg: Lidar sequence semantic segmentation using multiple feature aggregation. IEEE Robotics and Automation Letters, 7(4):9739-9746, 2022. +[27] Pengchuan Xiao, Zhenlei Shao, Steven Hao, Zishuo Zhang, Xiaolin Chai, Judy Jiao, Zesong Li, Jian Wu, Kai Sun, Kun Jiang, et al. Pandaset: Advanced sensor suite dataset for autonomous driving. In 2021 IEEE International Intelligent Transportation Systems Conference (ITSC), pages 3095-3101. IEEE, 2021. +[28] Chenfeng Xu, Bichen Wu, Zining Wang, Wei Zhan, Peter Vajda, Kurt Keutzer, and Masayoshi Tomizuka. Squeeze-segv3: Spatially-adaptive convolution for efficient pointcloud segmentation. In European Conference on Computer Vision, pages 1-19. Springer, 2020. +[29] Jianyun Xu, Ruixiang Zhang, Jian Dou, Yushi Zhu, Jie Sun, and Shiliang Pu. Rpvnet: A deep and efficient range-point-voxel fusion network for lidar point cloud segmentation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 16024-16033, 2021. +[30] Xu Yan, Jiantao Gao, Chaoda Zheng, Chao Zheng, Ruimao Zhang, Shuguang Cui, and Zhen Li. 2dpass: 2d priors assisted semantic segmentation on lidar point clouds. In European Conference on Computer Vision, pages 677-695. Springer, 2022. +[31] Maosheng Ye, Shuangjie Xu, Tongyi Cao, and Qifeng Chen. Drinet: A dual-representation iterative learning network for point cloud segmentation. In Proceedings of the IEEE/CVF international conference on computer vision, pages 7447-7456, 2021. +[32] Yang Zhang, Zixiang Zhou, Philip David, Xiangyu Yue, Zerong Xi, Boqing Gong, and Hassan Foroosh. Polarnet: An improved grid representation for online lidar point clouds semantic segmentation. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9601-9610, 2020. +[33] Zixiang Zhou, Yang Zhang, and Hassan Foroosh. Panoptic-polarnet: Proposal-free lidar point cloud panoptic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13194-13203, 2021. +[34] Xinge Zhu, Hui Zhou, Tai Wang, Fangzhou Hong, Yuexin Ma, Wei Li, Hongsheng Li, and Dahua Lin. Cylindrical and asymmetrical 3d convolution networks for lidar segmentation. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 9939-9948, 2021. \ No newline at end of file diff --git a/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/images.zip b/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..c7892b87f382a5717376a9ea2eb4cb1cf5988836 --- /dev/null +++ b/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:0f56228c2db7fef1d59f002f173e4f965a2d727bd71dcb4d2bcd62ebf3a22d12 +size 439433 diff --git a/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/layout.json b/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..5cc5b8b12198576f60f2e1496d53560250631645 --- /dev/null +++ b/2023/MemorySeg_ Online LiDAR Semantic Segmentation with a Latent Memory/layout.json @@ -0,0 +1,7244 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 64, + 103, + 529, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 64, + 103, + 529, + 121 + ], + "spans": [ + { + "bbox": [ + 64, + 103, + 529, + 121 + ], + "type": "text", + "content": "MemorySeg: Online LiDAR Semantic Segmentation with a Latent Memory" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 188, + 144, + 407, + 186 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 188, + 144, + 407, + 186 + ], + "spans": [ + { + "bbox": [ + 188, + 144, + 407, + 186 + ], + "type": "text", + "content": "Enxu Li Sergio Casas Raquel Urtasun Waabi University of Toronto {tli, sergio, urtasun}@waabi.ai" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "spans": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 239, + 290, + 574 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 239, + 290, + 574 + ], + "spans": [ + { + "bbox": [ + 46, + 239, + 290, + 574 + ], + "type": "text", + "content": "Semantic segmentation of LiDAR point clouds has been widely studied in recent years, with most existing methods focusing on tackling this task using a single scan of the environment. However, leveraging the temporal stream of observations can provide very rich contextual information on regions of the scene with poor visibility (e.g., occlusions) or sparse observations (e.g., at long range), and can help reduce redundant computation frame after frame. In this paper, we tackle the challenge of exploiting the information from the past frames to improve the predictions of the current frame in an online fashion. To address this challenge, we propose a novel framework for semantic segmentation of a temporal sequence of LiDAR point clouds that utilizes a memory network to store, update and retrieve past information. Our framework also includes a novel regularizer that penalizes prediction variations in the neighborhood of the point cloud. Prior works have attempted to incorporate memory in range view representations for semantic segmentation, but these methods fail to handle occlusions and the range view representation of the scene changes drastically as agents nearby move. Our proposed framework overcomes these limitations by building a sparse 3D latent representation of the surroundings. We evaluate our method on SemanticKITTI, nuScenes, and PandaSet. Our experiments demonstrate the effectiveness of the proposed framework compared to the state-of-the-art. For more information, visit the project website: https://waabi.ai/research/memoryseg." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 597, + 128, + 609 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 597, + 128, + 609 + ], + "spans": [ + { + "bbox": [ + 47, + 597, + 128, + 609 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 287, + 715 + ], + "type": "text", + "content": "Semantic segmentation of LiDAR point clouds is a key component for the safe deployment of self-driving vehicles (SDV). It enables SDVs to enhance their understanding of the surrounding environment by categorizing every 3D point into specific classes of interest, such as vehicles, pedestrians, traffic signs, buildings, roadways, etc. This rich and precise 3D representation of the environment can then be used for various applications such as generating online or" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 306, + 215, + 423, + 323 + ], + "blocks": [ + { + "bbox": [ + 306, + 215, + 423, + 323 + ], + "lines": [ + { + "bbox": [ + 306, + 215, + 423, + 323 + ], + "spans": [ + { + "bbox": [ + 306, + 215, + 423, + 323 + ], + "type": "image", + "image_path": "5bb242696325f5413353a18ba9d10318de2d8beb984d13165a23469698b2feb8.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 327, + 547, + 381 + ], + "lines": [ + { + "bbox": [ + 305, + 327, + 547, + 381 + ], + "spans": [ + { + "bbox": [ + 305, + 327, + 547, + 381 + ], + "type": "text", + "content": "Figure 1. Objects could be partially occluded in single frame LiDAR point cloud. Our approach learns a 3D latent memory representation for better contextualizing the online observations. We apply PCA [14] to reduce the latent dimension to 3 and plot as RGB. (Best viewed in color and zoomed-in.)" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 426, + 215, + 547, + 324 + ], + "blocks": [ + { + "bbox": [ + 426, + 215, + 547, + 324 + ], + "lines": [ + { + "bbox": [ + 426, + 215, + 547, + 324 + ], + "spans": [ + { + "bbox": [ + 426, + 215, + 547, + 324 + ], + "type": "image", + "image_path": "117f91f4cb516d038ac16fc603a00cf7e95bcd53d2648f90be1a404ab033d4e8.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 396, + 545, + 422 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 396, + 545, + 422 + ], + "spans": [ + { + "bbox": [ + 305, + 396, + 545, + 422 + ], + "type": "text", + "content": "offline semantic maps, building localization priors, or making the shapes of an object tracker more precise." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 423, + 546, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 423, + 546, + 555 + ], + "spans": [ + { + "bbox": [ + 304, + 423, + 546, + 555 + ], + "type": "text", + "content": "LiDAR data is typically captured as a continuous stream of data, where every fraction of a second (typically 100ms) a new point cloud is available. Despite this fact, most LiDAR segmentation approaches process each frame independently [15, 32, 28, 22, 34, 5, 29] due to the computational and memory complexity associated with processing large amounts of 3D point cloud data. However, reasoning about a single frame suffers from the sparsity of the observations, particularly at range, and has difficulty handling occluded objects. Furthermore, the absence of motion information can make categorizing certain objects difficult." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 547, + 715 + ], + "type": "text", + "content": "Several approaches [20, 19] utilize a sliding window approach, where a small set of past frames is processed independently at every time step. The main shortcoming of this approach is its limited temporal context (typically under 1 second) due to resource constraints, as processing multiple LiDAR scans at once is expensive. TemporalLidarSeg [8] proposed to utilize a latent spatial memory to retain information about the past while avoiding redundant computation every time a new scan is available, in a range view (RV) representation. However, the RV of the scene changes drastically as the SDV or the other actors move due to changes in perspective. As a result, the memory can be dominated by nearby objects, which appear larger in the RV representen" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "text", + "content": "745" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 49, + 72, + 286, + 263 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 72, + 286, + 263 + ], + "spans": [ + { + "bbox": [ + 49, + 72, + 286, + 263 + ], + "type": "text", + "content": "tation, making it challenging to be updated from frame to frame. Occlusion can be particularly challenging as the occluder now occupies the same spatial region that was previously describing the occluded object. This limits the usefulness of the memory. In contrast to RV, 3D is a metric space where the distances between points are preserved regardless of the viewpoint or relative distance to the SDV. Thus, representing the memory in 3D enables learning size priors for different classes. It allocates equal representation power to them regardless of the distance to the SDV, and enables easy understanding of motion. Moreover, previously observed regions that are currently occluded can be remembered in the memory as the occluder and occluded objects occupy different 3D regions, even though they share the same space in RV. Despite these advantages, 3D memory has been overlooked in LiDAR semantic segmentation." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 266, + 286, + 385 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 266, + 286, + 385 + ], + "spans": [ + { + "bbox": [ + 49, + 266, + 286, + 385 + ], + "type": "text", + "content": "In this paper we propose MEMORYSEG, a novel online LiDAR segmentation model that recurrently updates a sparse 3D latent memory as new observations are received, efficiently and effectively accumulating evidence from past observations. Fig. 1 illustrates the expressive power of such memory. In a single scan, objects are hard to identify due to sparsity (particularly at range) and lack of semantics, and occluded areas have no observations. In contrast, our latent memory is much denser, providing a rich context to separate different classes, especially in currently occluded regions." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 388, + 286, + 650 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 388, + 286, + 650 + ], + "spans": [ + { + "bbox": [ + 49, + 388, + 286, + 650 + ], + "type": "text", + "content": "To achieve an effective memory update that takes into account both the past and the present for accurate decoding, our method addresses several challenges. First, we align the previous memory with the current observation in the latest ego frame, to compensate for the SDV motion. Second, the sparsity level of the memory and the observation embeddings are different, making fusion non-trivial. The latent memory is denser, and thus some currently unobserved locations may be present in the memory. Complementarily, some regions in the current scan have not been observed before, such as new observations appearing as the SDV drives further. For this reason, we propose a mechanism to fill in missing regions in the current observations and add new observations to the memory during the update. Third, other objects are also moving (potentially in opposite direction), thus fusing the memory and observation embeddings requires a large receptive field. We address this via a carefully designed architecture that achieves a large receptive field yet preserves sparsity for efficiency. Additionally, we introduce a novel point-level neighbourhood variation regularizer which penalizes significant differences in semantic predictions within local 3D neighborhoods." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 653, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 653, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 49, + 653, + 286, + 712 + ], + "type": "text", + "content": "Extensive experiments in SemanticKITTI [2], nuScenes [4] and PandaSet [27] demonstrate that MEMORYSEG outperforms current state-of-the-art semantic segmentation methods that rely purely on LiDAR on multiple benchmarks." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 309, + 72, + 391, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 72, + 391, + 83 + ], + "spans": [ + { + "bbox": [ + 309, + 72, + 391, + 83 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 309, + 92, + 545, + 127 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 92, + 545, + 127 + ], + "spans": [ + { + "bbox": [ + 309, + 92, + 545, + 127 + ], + "type": "text", + "content": "In this section, we start by reviewing LiDAR semantic segmentation approaches in the literature and then focus on methods proposed for temporal LiDAR reasoning." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 309, + 137, + 473, + 148 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 137, + 473, + 148 + ], + "spans": [ + { + "bbox": [ + 309, + 137, + 473, + 148 + ], + "type": "text", + "content": "2.1. LiDAR Semantic Segmentation" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 309, + 156, + 545, + 215 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 156, + 545, + 215 + ], + "spans": [ + { + "bbox": [ + 309, + 156, + 545, + 215 + ], + "type": "text", + "content": "LiDAR-based semantic segmentation methods can be classified into four categories based on the type of data being processed: point-based [16, 17, 13, 24], projection-based [28, 7, 32], voxel-based [5, 34, 12], or a combination of the data representations [22, 29]." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 309, + 216, + 545, + 312 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 216, + 545, + 312 + ], + "spans": [ + { + "bbox": [ + 309, + 216, + 545, + 312 + ], + "type": "text", + "content": "Point-based approaches [16, 17, 13, 24] operate directly on the point cloud, but most [17, 13, 24] rely on down-sampling to accommodate limited computational resources. KPCov [24] introduces customized spatial kernel-based point convolution which yields the most favorable outcomes compared to other point-based methods. However, it requires a significant amount of computational resources, which can limit its practicality in certain applications." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 309, + 312, + 545, + 418 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 312, + 545, + 418 + ], + "spans": [ + { + "bbox": [ + 309, + 312, + 545, + 418 + ], + "type": "text", + "content": "Projection-based methods [28, 7, 32] involve projecting a 3D point cloud onto a 2D image plane, which can be done using either in spherical Range-View [28, 7], BirdEye-View [32], or multi-view representations [11]. These approaches usually operate in real-time, benefiting from efficient 2D CNN inference on GPUs. However, they suffer from significant information loss due to projection, which can prevent them from being on par with state-of-the-art methods." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 309, + 421, + 545, + 503 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 421, + 545, + 503 + ], + "spans": [ + { + "bbox": [ + 309, + 421, + 545, + 503 + ], + "type": "text", + "content": "The emergence of 3D voxel-based approaches [5, 34, 12] can be attributed to recent advancements in sparse 3D convolutions [6, 21]. Typically, LiDAR point clouds are converted into Cartesian [5] or Cylindrical [34] voxels and then processed using sparse convolutions. They have demonstrated state-of-the-art performance, but reducing voxel resolution can result in significant loss of information." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 309, + 505, + 545, + 600 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 505, + 545, + 600 + ], + "spans": [ + { + "bbox": [ + 309, + 505, + 545, + 600 + ], + "type": "text", + "content": "Recently, researchers have explored the potential of leveraging multiple data representations [22, 30, 29, 31] to benefit from the information acquired by each representation. For instance, SPVNAS [22] incorporates both pointwise features and 3D-voxel features in their network while learning to segment. Similarly, RPVNet [29] utilizes a trilateral structure in their network, where each branch adopts a distinct data representation mentioned earlier." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 309, + 601, + 545, + 660 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 601, + 545, + 660 + ], + "spans": [ + { + "bbox": [ + 309, + 601, + 545, + 660 + ], + "type": "text", + "content": "Our method takes a similar approach to incorporate both point and voxel representations in the network. Voxel representations are utilized for contextual information learning, while point representations are employed to preserve fine-grained details, such as object boundaries and curvatures." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 309, + 670, + 461, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 670, + 461, + 682 + ], + "spans": [ + { + "bbox": [ + 309, + 670, + 461, + 682 + ], + "type": "text", + "content": "2.2. Temporal LiDAR Reasoning" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 309, + 689, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 689, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 309, + 689, + 545, + 712 + ], + "type": "text", + "content": "Previous methods [20, 19, 26] have attempted to integrate a small number of past frames to facilitate temporal" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 298, + 750, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 750, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 298, + 750, + 312, + 757 + ], + "type": "text", + "content": "746" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 252 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 252 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 252 + ], + "type": "text", + "content": "reasoning. For instance, SpSequenceNet [20] introduces cross-frame global attention, which uses information from the previous frame to emphasize features in the current frame. Additionally, it utilizes cross-frame local interpolation to combine local features from both the previous and current frame. Further, MetaRangeSeg [26] includes information from past frames by having the residual depth map as an additional feature to the input. However, these methods are not well-suited for continuous application to a temporal sequence of LiDAR point clouds. Firstly, they are inefficient as they discard previous observations and require the model to start from scratch each time a new point cloud is received. Secondly, they only aggregate temporal information within a short horizon, failing to capture the potential of temporal reasoning over a longer duration." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 255, + 289, + 448 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 255, + 289, + 448 + ], + "spans": [ + { + "bbox": [ + 46, + 255, + 289, + 448 + ], + "type": "text", + "content": "Several works [8, 9] have attempted to incorporate temporal reasoning through a recurrent framework. Specifically, Duerr et al. [8] presents a recurrent segmentation architecture in RV, which uses previous observations as memory and aligns them temporally in the range image space. However, RV memory has limitations, such as prioritizing nearby objects, and suffering from contention of memory resources during occlusions (since information from behind the occluder and the occluder itself are now sharing the same memory entries). Further, StrObe [9] implemented a multi-scale 2D BEV memory for object detection enabling the network to take advantage of previous computations and process new LiDAR data incrementally. However, compared to object detection, semantic segmentation requires a more fine-grained and nuanced understanding of the scene and therefore a 3D memory is more suitable than 2D BEV." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 451, + 289, + 584 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 451, + 289, + 584 + ], + "spans": [ + { + "bbox": [ + 46, + 451, + 289, + 584 + ], + "type": "text", + "content": "Our approach is distinct from previous methods as we propose an online LiDAR semantic segmentation framework utilizing a sparse 3D memory. By representing the memory in 3D, we preserve the distance between points regardless of viewpoint or distance from the SDV, allowing for size priors of different classes to be learned. Additionally, the memory also retains previously observed regions even when currently occluded, as occluders and occluded objects occupy different 3D regions, despite being in the same space in RV. Furthermore, we preserve fine-grained height details that are lost in the BEV memory." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 605, + 270, + 620 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 605, + 270, + 620 + ], + "spans": [ + { + "bbox": [ + 47, + 605, + 270, + 620 + ], + "type": "text", + "content": "3.3D Memory-based LiDAR Segmentation" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "content": "In this section we introduce MEMORYSEG, an online semantic segmentation framework for streaming LiDAR point clouds that leverages a 3D latent memory to remember the past and better handle occlusions and sparse observations. In the remainder of this section, we first describe our model formulation, then present the network architecture and finally explain the learning process." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 305, + 72, + 421, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 421, + 84 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 421, + 84 + ], + "type": "text", + "content": "3.1. Model Formulation" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "spans": [ + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "content": "Let " + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "inline_equation", + "content": "\\mathcal{P} = \\{\\mathcal{P}_t\\}_{t=1}^L" + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "content": " be a sequence of LiDAR sweeps where " + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "inline_equation", + "content": "L \\in \\mathbb{N}^+" + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "content": " is the sequence length and " + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "inline_equation", + "content": "t \\in [1, L]" + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "content": " is the time index. Each LiDAR sweep " + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "inline_equation", + "content": "\\mathcal{P}_t = (\\mathbf{G}_t, \\mathbf{F}_t)" + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "content": " is a " + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "inline_equation", + "content": "360^\\circ" + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "content": " scan of the surrounding with " + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "inline_equation", + "content": "N_t" + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "content": " unordered points. " + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "inline_equation", + "content": "\\mathbf{G}_t \\in \\mathbb{R}^{N_t \\times 3}" + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "content": " contains the Cartesian coordinates in the ego vehicle frame and " + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_t \\in \\mathbb{R}^{N_t}" + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "content": " is the LiDAR intensity of the point. Let " + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "inline_equation", + "content": "\\mathbf{T}_{t-1 \\to t} \\in SE(3)" + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "content": " be the pose transformation from the vehicle frame at time " + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "inline_equation", + "content": "t-1" + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 89, + 545, + 185 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "spans": [ + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "text", + "content": "To make informed semantic predictions, in this paper we maintain a latent (or hidden) memory in 3D. This memory is sparse in nature since the majority of the 3D space is unoccupied. To represent this sparsity, we parametrize the memory at time " + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "text", + "content": " using a sparse set of voxels containing the coordinates " + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "inline_equation", + "content": "H_{G,t} \\in \\mathbb{R}^{M_t \\times 3}" + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "text", + "content": " and their corresponding learned embeddings " + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "inline_equation", + "content": "H_{F,t} \\in \\mathbb{R}^{M_t \\times d_m}" + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "inline_equation", + "content": "M_t" + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "text", + "content": " is the number of voxel entries in the latent memory at time " + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "inline_equation", + "content": "d_m" + }, + { + "bbox": [ + 304, + 186, + 546, + 353 + ], + "type": "text", + "content": " is the embedding dimension. Preserving the voxel coordinates is important to perform alignment as the reference changes when the SDV moves. We utilize a voxel-based sparse representation as it provides notable computational benefits with respect to dense tensors as well as sparse representations at the point level without sacrificing performance." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 354, + 547, + 472 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 354, + 547, + 472 + ], + "spans": [ + { + "bbox": [ + 304, + 354, + 547, + 472 + ], + "type": "text", + "content": "Inference follows a three-step process that is repeated every time a new LiDAR sweep is available: (i) the encoder takes in the most recent LiDAR point cloud at current time " + }, + { + "bbox": [ + 304, + 354, + 547, + 472 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 354, + 547, + 472 + ], + "type": "text", + "content": " and extracts point-level and voxel-level observation embeddings, (ii) the latent memory is updated taking into account the voxel-level embeddings from the new observations, and (iii) the semantic predictions are decoded by combining the point-level embeddings from the encoder and voxel-level embeddings from the updated memory. We refer the reader to Fig. 2 for an illustration of our method." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 473, + 547, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 473, + 547, + 616 + ], + "spans": [ + { + "bbox": [ + 304, + 473, + 547, + 616 + ], + "type": "text", + "content": "The memory update stage faces challenges due to the changing reference frame as the SDV moves, different sparsity levels of memory and current LiDAR sweep, as well as the motion of other actors. To address these challenges, a Feature Alignment Module (FAM) is introduced to align the previous memory state with the current observation embeddings. Subsequently, an Adaptive Padding Module (APM) is utilized to fill in missing observations in the current data and add new observations to the memory. Then, a Memory Refinement Module (MRM) is employed to update the latent memory using padded observations. Next, we explain each component in more detail." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 617, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 547, + 715 + ], + "type": "text", + "content": "Encoder: Following [22], our encoder is composed of a point-branch that computes point-level embeddings preserving the fine details and a voxel-branch that performs contextual reasoning through 3D sparse convolutional blocks [21]. The point-branch receives a 7-dimensional feature vector per point, with the xyz coordinates, intensity, and relative offsets to the nearest voxel center as features. It comprises two shared MLPs that output point embeddings," + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 297, + 748, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 748, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 748, + 312, + 757 + ], + "type": "text", + "content": "747" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 61, + 72, + 531, + 194 + ], + "blocks": [ + { + "bbox": [ + 61, + 72, + 531, + 194 + ], + "lines": [ + { + "bbox": [ + 61, + 72, + 531, + 194 + ], + "spans": [ + { + "bbox": [ + 61, + 72, + 531, + 194 + ], + "type": "image", + "image_path": "dd010bd514f353a03c675e261fa2550d17534abb629a6c20ad5802aa64f0b154.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 198, + 547, + 232 + ], + "lines": [ + { + "bbox": [ + 46, + 198, + 547, + 232 + ], + "spans": [ + { + "bbox": [ + 46, + 198, + 547, + 232 + ], + "type": "text", + "content": "Figure 2. An overview of our model, MEMORYSEG. After the encoder processes the LiDAR point cloud at time " + }, + { + "bbox": [ + 46, + 198, + 547, + 232 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 198, + 547, + 232 + ], + "type": "text", + "content": ", the resulting feature map is utilized to update the latent memory (see Fig. 3 for more details about the memory update). Then, the decoder combines the refined memory with the point embeddings from the encoder to obtain semantic predictions." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 48, + 248, + 289, + 318 + ], + "blocks": [ + { + "bbox": [ + 48, + 248, + 289, + 318 + ], + "lines": [ + { + "bbox": [ + 48, + 248, + 289, + 318 + ], + "spans": [ + { + "bbox": [ + 48, + 248, + 289, + 318 + ], + "type": "image", + "image_path": "eb7a6e4abb0d0d94406f0da981144bf80ef8d0201ed05dc3925138e3d8049b63.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 320, + 289, + 420 + ], + "lines": [ + { + "bbox": [ + 46, + 320, + 289, + 420 + ], + "spans": [ + { + "bbox": [ + 46, + 320, + 289, + 420 + ], + "type": "text", + "content": "Figure 3. Overview of the latent memory update process. The latent memory embeddings " + }, + { + "bbox": [ + 46, + 320, + 289, + 420 + ], + "type": "inline_equation", + "content": "(H_{G,t - 1},H_{F,t - 1})" + }, + { + "bbox": [ + 46, + 320, + 289, + 420 + ], + "type": "text", + "content": " are transformed to the ego frame at " + }, + { + "bbox": [ + 46, + 320, + 289, + 420 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 320, + 289, + 420 + ], + "type": "text", + "content": " with the Feature Alignment Module (FAM). Next, the Adaptive Padding Module (APM) is utilized to learn the padding of both memory and observation embeddings. The Memory Refinement Module (MRM) updates the latent memory by incorporating the padded observation embeddings. The updated memory is then passed to the decoder for generating semantic predictions. (Best viewed in color and zoomed-in.)" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 433, + 287, + 577 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 433, + 287, + 577 + ], + "spans": [ + { + "bbox": [ + 46, + 433, + 287, + 577 + ], + "type": "text", + "content": "as illustrated in Fig. 2. We average point embeddings belonging to the same voxel from the first shared MLP over voxels of size " + }, + { + "bbox": [ + 46, + 433, + 287, + 577 + ], + "type": "inline_equation", + "content": "v_{b}" + }, + { + "bbox": [ + 46, + 433, + 287, + 577 + ], + "type": "text", + "content": " to obtain voxel features. These features are then processed through four residual blocks with 3D sparse convolutions, each downsampling the feature map by a factor of 2. Two additional residual blocks with 3D sparse convolutions are applied to upsample the sparse feature maps. Unlike a full U-Net [18] that recovers features at the original resolution, we only upsample to " + }, + { + "bbox": [ + 46, + 433, + 287, + 577 + ], + "type": "inline_equation", + "content": "\\frac{1}{4}" + }, + { + "bbox": [ + 46, + 433, + 287, + 577 + ], + "type": "text", + "content": " of the original size for computational efficiency reasons, and use the coarser features to update the latent memory before decoding finer details to output our semantic predictions." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": "Feature Alignment: The reference frame changes as the SDV moves. We propose the Feature Alignment Module (FAM) to transform the latent memory from the ego frame at " + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "inline_equation", + "content": "t - 1" + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": " and align with the current observation embeddings. Specifically, we take the memory voxel coordinates " + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "inline_equation", + "content": "H_{G,t-1}" + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": " and use the pose information " + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{T}_{t-1 \\to t}" + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": " to project from the ego frame at " + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "inline_equation", + "content": "t - 1" + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": ". We then re-voxelize using the projected coordinates with a voxel size of " + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "inline_equation", + "content": "v_m" + }, + { + "bbox": [ + 46, + 582, + 288, + 714 + ], + "type": "text", + "content": ". If multiple entries are inside the same memory voxel, we take the average of them to be the voxel feature. The resulting warped coordinates and embeddings of the memory in the" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 250, + 531, + 262 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 250, + 531, + 262 + ], + "spans": [ + { + "bbox": [ + 304, + 250, + 531, + 262 + ], + "type": "text", + "content": "ego frame " + }, + { + "bbox": [ + 304, + 250, + 531, + 262 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 250, + 531, + 262 + ], + "type": "text", + "content": " are denoted as " + }, + { + "bbox": [ + 304, + 250, + 531, + 262 + ], + "type": "inline_equation", + "content": "\\tilde{H}_{G,t}" + }, + { + "bbox": [ + 304, + 250, + 531, + 262 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 250, + 531, + 262 + ], + "type": "inline_equation", + "content": "\\tilde{H}_{F,t}" + }, + { + "bbox": [ + 304, + 250, + 531, + 262 + ], + "type": "text", + "content": ", respectively." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "spans": [ + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "text", + "content": "Adaptive Padding: To handle the different sparsity of the latent memory and the voxel-level observation embeddings, we propose the Adaptive Padding Module (APM). We refer the readers to Fig. 3 for an illustration. First, we re-voxelize the encoder features with the same voxel size " + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "inline_equation", + "content": "v_{m}" + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "text", + "content": " where entries within the same voxel are averaged. We denote the resulting coordinates and embeddings as " + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "inline_equation", + "content": "X_{G}" + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "inline_equation", + "content": "X_{F}" + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "text", + "content": ". Note that we omit " + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "text", + "content": " in this section for brevity. Let " + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "inline_equation", + "content": "x_{G} \\subseteq X_{G}" + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "inline_equation", + "content": "x_{F} \\subseteq X_{F}" + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "text", + "content": " be the coordinates and embeddings of the new observations at time " + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "text", + "content": " that are not present in the memory. To obtain an initial guess of the memory embedding for a new entry, we utilize a weighted aggregation approach within its surrounding neighbourhood. This involves taking into account the coordinate offsets relative to the existing neighbouring voxels in the memory, which provides insight into their importance for aggregation, similar to Continuous Conv [25]. In addition to this, we incorporate the feature similarities and feature distances as additional cues for the aggregation process. Encoding feature similarities is particularly useful for assigning weights to the neighborhood. In a dynamic scene with moving actors, the closest voxel may not always be the most important voxel. By providing feature similarities, the network can make more informed decisions. The goal of such completion is to make a hypothesis of the embedding at the previously unobserved location using the available information. More precisely, we add those entries in the memory where their coordinates are " + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "inline_equation", + "content": "h_{G}^{\\prime} = x_{G}" + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "text", + "content": " and the embedding of each voxel " + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 304, + 264, + 545, + 598 + ], + "type": "text", + "content": " are initialized as follows," + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 374, + 608, + 545, + 635 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 374, + 608, + 545, + 635 + ], + "spans": [ + { + "bbox": [ + 374, + 608, + 545, + 635 + ], + "type": "interline_equation", + "content": "h _ {F, j} ^ {\\prime} = \\sum_ {i \\in \\Omega_ {\\tilde {H}} (j)} w _ {j i} \\tilde {H} _ {F, i}, \\tag {1}", + "image_path": "c4aaaaecadf83dbc3b675c9f7db643ec7d303a93ce62d31e6531131d89e65995.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 310, + 651, + 545, + 681 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 651, + 545, + 681 + ], + "spans": [ + { + "bbox": [ + 310, + 651, + 545, + 681 + ], + "type": "interline_equation", + "content": "w _ {j i} = \\psi \\left(\\tilde {H} _ {G, i} - x _ {G, j}, \\| \\tilde {H} _ {F, i} - x _ {F, j} \\|, \\frac {\\tilde {H} _ {F , i} \\cdot x _ {F , j}}{\\| \\tilde {H} _ {F , i} \\| \\| x _ {F , j} \\|}\\right), \\tag {2}", + "image_path": "2d2bb0e3be0559a6b31cb211508e666fd048d57d798c9ed705b0c15725f372f1.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "text", + "content": " are voxel indices, " + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\Omega_{\\tilde{H}}(j)" + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "text", + "content": " is the k-nearest-neighborhood of voxel " + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "text", + "content": " in " + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\tilde{H}_G" + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\psi" + }, + { + "bbox": [ + 304, + 688, + 547, + 714 + ], + "type": "text", + "content": " is a shared MLP" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "type": "text", + "content": "748" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 96 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 96 + ], + "type": "text", + "content": "followed by a softmax layer on the dimension of neighbourhood to ensure " + }, + { + "bbox": [ + 46, + 72, + 287, + 96 + ], + "type": "inline_equation", + "content": "\\sum_{i}w_{ji} = 1" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 96, + 287, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 96, + 287, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 96, + 287, + 156 + ], + "type": "text", + "content": "Second, we identify the regions in the memory that are unseen in the current observation and denote their coordinates and embeddings as " + }, + { + "bbox": [ + 46, + 96, + 287, + 156 + ], + "type": "inline_equation", + "content": "\\tilde{h}_G \\subseteq \\tilde{H}_G" + }, + { + "bbox": [ + 46, + 96, + 287, + 156 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 96, + 287, + 156 + ], + "type": "inline_equation", + "content": "\\tilde{h}_F \\subseteq \\tilde{H}_F" + }, + { + "bbox": [ + 46, + 96, + 287, + 156 + ], + "type": "text", + "content": ". We add entries " + }, + { + "bbox": [ + 46, + 96, + 287, + 156 + ], + "type": "inline_equation", + "content": "x_G'" + }, + { + "bbox": [ + 46, + 96, + 287, + 156 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 96, + 287, + 156 + ], + "type": "inline_equation", + "content": "x_F'" + }, + { + "bbox": [ + 46, + 96, + 287, + 156 + ], + "type": "text", + "content": " to complete the current observation in a similar manner." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 158, + 287, + 195 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 158, + 287, + 195 + ], + "spans": [ + { + "bbox": [ + 47, + 158, + 287, + 195 + ], + "type": "text", + "content": "Memory Refinement: We design a sparse version of a ConvGRU [1] to update the latent memory " + }, + { + "bbox": [ + 47, + 158, + 287, + 195 + ], + "type": "inline_equation", + "content": "H_{F,t-1}^{\\prime}" + }, + { + "bbox": [ + 47, + 158, + 287, + 195 + ], + "type": "text", + "content": " using the current padded observation embeddings " + }, + { + "bbox": [ + 47, + 158, + 287, + 195 + ], + "type": "inline_equation", + "content": "X_{F,t}^{\\prime}" + }, + { + "bbox": [ + 47, + 158, + 287, + 195 + ], + "type": "text", + "content": " as follows:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 91, + 205, + 287, + 270 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 205, + 287, + 270 + ], + "spans": [ + { + "bbox": [ + 91, + 205, + 287, + 270 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} r _ {t} = \\operatorname {s i g m o i d} \\left[ \\Psi_ {r} \\left(X _ {F, t} ^ {\\prime}, H _ {F, t - 1} ^ {\\prime}\\right) \\right], \\\\ z _ {t} = \\operatorname {s i g m o i d} \\left[ \\Psi_ {z} \\left(X _ {F, t} ^ {\\prime}, H _ {F, t - 1} ^ {\\prime}\\right) \\right], \\\\ \\hat {H} _ {F, t} = \\tanh \\left[ \\Psi_ {u} \\left(X _ {F, t} ^ {\\prime}, r _ {t} \\cdot H _ {F, t - 1} ^ {\\prime}\\right) \\right], \\tag {3} \\\\ H _ {F, t} = \\hat {H} _ {F, t} \\cdot z _ {t} + H _ {F, t - 1} ^ {\\prime} \\cdot (1 - z _ {t}), \\\\ \\end{array}", + "image_path": "9040aa9202322955f5cfc5892ce1292f4289154d201141b60944bc465622710c.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 278, + 287, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 278, + 287, + 361 + ], + "spans": [ + { + "bbox": [ + 46, + 278, + 287, + 361 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 278, + 287, + 361 + ], + "type": "inline_equation", + "content": "\\Psi_r, \\Psi_z, \\Psi_u" + }, + { + "bbox": [ + 46, + 278, + 287, + 361 + ], + "type": "text", + "content": " are sparse 3D convolutional blocks with downsampling layers that aim to expand the receptive field and upsampling layers that restore the embeddings to their original size. " + }, + { + "bbox": [ + 46, + 278, + 287, + 361 + ], + "type": "inline_equation", + "content": "r_t" + }, + { + "bbox": [ + 46, + 278, + 287, + 361 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 278, + 287, + 361 + ], + "type": "inline_equation", + "content": "z_t" + }, + { + "bbox": [ + 46, + 278, + 287, + 361 + ], + "type": "text", + "content": " are learned signals to reset or update the memory, respectively. We refer the readers to the supplementary material about the detailed architecture of the sparse convolutional blocks." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 364, + 287, + 508 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 364, + 287, + 508 + ], + "spans": [ + { + "bbox": [ + 46, + 364, + 287, + 508 + ], + "type": "text", + "content": "Decoder: Our decoder consists of an MLP, two residual blocks with sparse 3D convolutions, and a linear semantic header. Specifically, we first take the corresponding memory embeddings at coordinates " + }, + { + "bbox": [ + 46, + 364, + 287, + 508 + ], + "type": "inline_equation", + "content": "\\mathbf{G}_t" + }, + { + "bbox": [ + 46, + 364, + 287, + 508 + ], + "type": "text", + "content": " and add with the point embeddings from the encoder. The resulting combined embeddings are then voxelized with voxel size of " + }, + { + "bbox": [ + 46, + 364, + 287, + 508 + ], + "type": "inline_equation", + "content": "\\frac{v_b}{4}" + }, + { + "bbox": [ + 46, + 364, + 287, + 508 + ], + "type": "text", + "content": " and further processed by two residual blocks that upsample the feature maps back to the original resolution. In parallel, an MLP takes the point embeddings before voxelization to retain the fine-grained details. Finally, the semantic header takes the combination of voxel and point embeddings to obtain per-point semantic predictions." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 510, + 287, + 546 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 510, + 287, + 546 + ], + "spans": [ + { + "bbox": [ + 47, + 510, + 287, + 546 + ], + "type": "text", + "content": "Memory Initialization: At the start of the sequence (" + }, + { + "bbox": [ + 47, + 510, + 287, + 546 + ], + "type": "inline_equation", + "content": "t = 0" + }, + { + "bbox": [ + 47, + 510, + 287, + 546 + ], + "type": "text", + "content": "), the first observation is used to initialize memory, with " + }, + { + "bbox": [ + 47, + 510, + 287, + 546 + ], + "type": "inline_equation", + "content": "H_{G,0} = X_{G,0}" + }, + { + "bbox": [ + 47, + 510, + 287, + 546 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 510, + 287, + 546 + ], + "type": "inline_equation", + "content": "H_{F,0} = X_{F,0}" + }, + { + "bbox": [ + 47, + 510, + 287, + 546 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 554, + 113, + 566 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 554, + 113, + 566 + ], + "spans": [ + { + "bbox": [ + 47, + 554, + 113, + 566 + ], + "type": "text", + "content": "3.2. Learning" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 572, + 287, + 620 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 572, + 287, + 620 + ], + "spans": [ + { + "bbox": [ + 46, + 572, + 287, + 620 + ], + "type": "text", + "content": "We learn our segmentation model by minimizing a linear combination of conventional segmentation loss functions [13, 34, 22] and a novel point-wise regularizer to better supervise the network training." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 93, + 631, + 287, + 644 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 93, + 631, + 287, + 644 + ], + "spans": [ + { + "bbox": [ + 93, + 631, + 287, + 644 + ], + "type": "interline_equation", + "content": "J = \\beta_ {w c e} J _ {w c e} + \\beta_ {l s} J _ {l s} + \\beta_ {r e g} J _ {r e g}. \\tag {4}", + "image_path": "f5b8600baf8a608539d6ef22996d2817a70036e84b3fc637e9ac6fb8dd209d2c.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 653, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 287, + 713 + ], + "type": "text", + "content": "Here, " + }, + { + "bbox": [ + 46, + 653, + 287, + 713 + ], + "type": "inline_equation", + "content": "J_{wce}" + }, + { + "bbox": [ + 46, + 653, + 287, + 713 + ], + "type": "text", + "content": " denotes cross-entropy loss, weighted by the inverse frequency of classes, to address class imbalance in the dataset. The Lovasz Softmax Loss (" + }, + { + "bbox": [ + 46, + 653, + 287, + 713 + ], + "type": "inline_equation", + "content": "J_{ls}" + }, + { + "bbox": [ + 46, + 653, + 287, + 713 + ], + "type": "text", + "content": ") [3] is used to train the network, as it is a differentiable surrogate for the non-convex intersection over union (IoU) metric, which is" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "content": "a commonly used evaluation metric for semantic segmentation. Additionally, " + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "J_{reg}" + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "content": " corresponds to our proposed pointwise regularizer. " + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "\\beta_{reg}, \\beta_{wce}" + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "\\beta_{ls}" + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "content": " are hyperparameters." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 110, + 545, + 159 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 110, + 545, + 159 + ], + "spans": [ + { + "bbox": [ + 305, + 110, + 545, + 159 + ], + "type": "text", + "content": "Point-wise Smoothness: Our regularizer is designed to limit significant variations in semantic predictions within the 3D neighborhood of each point, except when these variations occur at the class boundary. Formally," + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 347, + 170, + 545, + 234 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 347, + 170, + 545, + 234 + ], + "spans": [ + { + "bbox": [ + 347, + 170, + 545, + 234 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} J _ {r e g} = \\frac {1}{N _ {t}} \\sum_ {\\substack {i = 1 \\\\ 1}} ^ {N _ {t}} | \\Delta (Y, i) - \\Delta (\\hat {Y}, i) |, \\tag{5} \\\\ \\Delta (Y, i) = \\Big | \\frac {1}{| \\Omega_ {\\mathcal {P} _ {t}} (i) |} \\sum_ {j \\in \\Omega_ {\\mathcal {P} _ {t}} (i)} | y _ {i} - y _ {j} | \\Big |. \\\\ \\end{array}", + "image_path": "15f17f567d813a4c56a1685fdd1b50d280926710affd78610344a62fb30b90b4.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "spans": [ + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": "Here, " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "\\Delta(Y, i)" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": " represents the ground truth semantic variation around point " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": ", while " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "\\Delta(\\hat{Y}, i)" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": " corresponds to the predicted semantic variation around point " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": ". We use " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "\\hat{Y} \\in \\mathbb{R}^{N_t \\times C}" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": " to denote the predicted semantic distribution over " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": " classes, and " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "Y \\in \\mathbb{R}^{N_t \\times C}" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": " to denote the ground truth semantic one-hot label. The variable " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "y_i" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": " represents the " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": "-th element of " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "Y" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "\\Omega_{\\mathcal{P}_t}(i)" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": " denotes the neighborhood of point " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": " in " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "\\mathcal{P}_t" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "inline_equation", + "content": "|\\Omega_{\\mathcal{P}_t}(i)|" + }, + { + "bbox": [ + 305, + 245, + 545, + 377 + ], + "type": "text", + "content": " represents the number of points in the neighborhood. The inspiration for this regularizer comes from a study by [11] that penalizes adjacent pixel prediction variations with the ground truth." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 391, + 387, + 403 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 391, + 387, + 403 + ], + "spans": [ + { + "bbox": [ + 306, + 391, + 387, + 403 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 411, + 545, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 411, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 305, + 411, + 545, + 555 + ], + "type": "text", + "content": "In this section, we thoroughly analyze the performance of our method on three different datasets: SemanticKITTI [2], nuScenes [4], and PandaSet [27]. These datasets were collected using different LiDAR sensors and in diverse geographical regions. Our results demonstrate that MEMORY-SEG outperforms the current state of the art in all benchmarks. Additionally, we conduct ablation studies to understand the impact of our contributions. We demonstrate that incorporating a 3D sparse latent memory improves semantic predictions, with a very significant gain in long-range areas as these are sparser and more often partially obstructed than short-range regions." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 557, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 557, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 557, + 545, + 713 + ], + "type": "text", + "content": "Datasets: We benchmark our approach on three large-scale autonomous driving datasets: SemanticKITTI [2] consists of 22 sequences from the KITTI Odometry Dataset [10], which was collected in Germany using a Velodyne HDL-64E LiDAR. We use the standard split where sequences 0 to 10 are used for training (with sequence 8 for validation), and sequences 11 to 21 are held for testing. We follow the standard setting where semantic labels are mapped to 19 classes for the single-scan benchmark and 25 for the multi-scan benchmark. In the latter, all movable classes are further divided into moving and non-moving classes. Given that prior research on temporal aggregation for semantic segmentation is more prevalent in" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "text", + "content": "749" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 49, + 70, + 544, + 167 + ], + "blocks": [ + { + "bbox": [ + 49, + 70, + 544, + 167 + ], + "lines": [ + { + "bbox": [ + 49, + 70, + 544, + 167 + ], + "spans": [ + { + "bbox": [ + 49, + 70, + 544, + 167 + ], + "type": "table", + "html": "
MethodmIoUCarBicycleMoonecycleTruckOther VehiclePersonBicyclistMoonecyclistRoadParkingSidewalkOther GroundBuildingFenceVegetationTrunkTerrainPoleTraffic Signcar (m)bicyclist (m)person (m)motorcycle (m)other-vehicle (m)truck (m)
TangentConv [23]34.184.92.018.221.118.51.60.00.083.938.364.015.385.849.179.543.256.736.431.240.31.16.41.930.142.2
DarkNet53Seg [2]41.684.130.432.920.220.77.50.00.091.664.975.327.585.256.578.450.764.838.153.361.514.115.20.228.937.8
KPConv [24]51.293.744.947.242.538.621.60.00.086.558.470.526.790.864.584.670.366.057.053.969.467.467.547.24.75.8
Cylinder3D [34]52.594.667.663.841.338.812.51.70.290.765.074.532.392.666.085.872.068.963.161.474.968.365.711.90.10.0
SpSequenceNet [20]43.188.524.026.229.222.76.30.00.090.157.673.927.191.266.884.066.065.750.848.753.241.226.236.22.30.1
TemporalLidarSeg [8]47.092.147.740.939.235.014.40.00.091.859.675.823.289.863.882.362.564.752.660.468.242.840.412.912.42.1
TemporalLatticeNet [19]47.191.635.436.126.923.09.40.00.091.559.375.327.589.665.384.666.770.457.260.459.741.751.048.85.90.0
Meta-RangeSeg [26]49.790.850.049.529.534.816.60.00.090.862.974.826.589.862.182.865.766.556.264.569.060.457.922.016.62.6
MEMORYSEG [ours]58.394.068.368.851.340.927.00.32.889.964.374.829.292.269.384.875.170.165.568.571.774.471.773.915.113.6
", + "image_path": "62f97c9815d0000fa18ca0e2f10e77a1d9534031784def7f62be593c95e85616.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 48, + 168, + 545, + 210 + ], + "lines": [ + { + "bbox": [ + 48, + 168, + 545, + 210 + ], + "spans": [ + { + "bbox": [ + 48, + 168, + 545, + 210 + ], + "type": "text", + "content": "Table 1. Comparison to the state-of-the-art methods on the test set of SemanticKITTI [2] multi-scan benchmark. (m) indicates moving. We include LiDAR-only published approaches at the time of submission. These approaches are categorized into two groups: the first group includes methods that aim for single-scan segmentation but use multiple aggregated frames as input; the second group consists of methods that introduce temporal aggregation modules explicitly tailored for handling multiple scans. Metrics are provided in [%]." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 221, + 286, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 221, + 286, + 460 + ], + "spans": [ + { + "bbox": [ + 49, + 221, + 286, + 460 + ], + "type": "text", + "content": "the multi-scan benchmark, we consider it more appropriate for evaluating our proposed method. Single-scan benchmark results are also provided in the supplementary material. nuScenes [4] was collected in Boston and Singapore using a Velodyne HDL-32E LiDAR sensor, which captures sparser point clouds that pose extra challenges for semantic reasoning. The dataset contains a total of 1000 scenes, with 700 scenes used for training, 150 for validation, and the remaining 150 held out for testing. Each scene contains about 40 labeled frames recorded at " + }, + { + "bbox": [ + 49, + 221, + 286, + 460 + ], + "type": "inline_equation", + "content": "2\\mathrm{Hz}" + }, + { + "bbox": [ + 49, + 221, + 286, + 460 + ], + "type": "text", + "content": ". We follow the standard setting which maps 31 fine-grained classes to 16 classes for training and evaluation. PandaSet [27] provides short sequences of temporal data but with a large number of moving actors in Silicon Valley. This dataset was collected using a Hesai-Pandar64 LiDAR and consists of 103 sequences, each with a length of 8 seconds. Following [8], we grouped the original fine-grained semantic classes into 14 for training and testing, trying to match the classes in other popular segmentation benchmarks [2, 4]. We also used the same train/Validation/test split as in the reference paper." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "content": "Implementation details: For all datasets, we first train the network without the memory update for single-scan segmentation for 50 epochs. Then, we freeze the encoder and train the memory update block and decoder in a recurrent fashion for an additional 20 epochs. During each training iteration, we use the first 10 consecutive sweeps as warmup memory, and then train the network with backpropagation through time (BPTT) on the next 3 frames. The memory voxel size " + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "inline_equation", + "content": "v_{m}" + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "content": " is " + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "inline_equation", + "content": "0.5\\mathrm{m}" + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "content": ", and the embedding dimension " + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "inline_equation", + "content": "d_{m}" + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "content": " is 128. We use the AdamW optimizer with a starting learning rate of 0.003 and a decay factor of 0.9. During training, we use data augmentation including global scaling sampled at random from [0.80, 1.20], translation sampled from [0, 0.2] m on all three axes, and global rotation around the Z axis with a random angle sampled from " + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "inline_equation", + "content": "[-\\pi ,\\pi ]" + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "content": ". We set the loss weights " + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "inline_equation", + "content": "\\beta_{wce}" + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "content": " to 1, " + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "inline_equation", + "content": "\\beta_{ls}" + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "content": " to 2, and " + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "inline_equation", + "content": "\\beta_{reg}" + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "content": " to 500. We set the regularizer neighborhood " + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "inline_equation", + "content": "\\Omega_{P_t}(i)" + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "content": " to be the closest 32 points around point " + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "content": ", and use a padding neighbourhood " + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "inline_equation", + "content": "\\Omega_{\\tilde{H}}(j)" + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "content": " to be the closest 5 voxels of voxel " + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 49, + 463, + 286, + 712 + ], + "type": "text", + "content": ". All experiments are conducted using 4 NVIDIA T4 GPUs with a batch size of 1 per GPU. During evaluation, we unroll each sequence from the" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 308, + 221, + 545, + 256 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 221, + 545, + 256 + ], + "spans": [ + { + "bbox": [ + 308, + 221, + 545, + 256 + ], + "type": "text", + "content": "first frame to the end and follow [34, 12] to apply test-time-augmentation, i.e. averaging prediction scores of 10 forward passes with augmented input from a single model." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 308, + 258, + 545, + 411 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 258, + 545, + 411 + ], + "spans": [ + { + "bbox": [ + 308, + 258, + 545, + 411 + ], + "type": "text", + "content": "To adapt to the uniqueness of each dataset, we consider the following per-dataset settings. To train on the SemanticKITTI dataset, we set the voxel size " + }, + { + "bbox": [ + 308, + 258, + 545, + 411 + ], + "type": "inline_equation", + "content": "v_{b}" + }, + { + "bbox": [ + 308, + 258, + 545, + 411 + ], + "type": "text", + "content": " to 0.05 m. Due to the limited quantities of movable actors in this dataset, following [33] we generate a library of instances from the training sequences and randomly inject 5 objects over the ground classes at each frame during training. To improve the ability to separate classes into moving and non-moving actors, we add another linear header to classify points as moving or static and fuse the results from the semantic header. More implementation details are provided in the supplementary material. For nuScenes, the voxel size is set to 0.1 m, and 0.125 m for PandaSet." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 308, + 414, + 545, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 414, + 545, + 533 + ], + "spans": [ + { + "bbox": [ + 308, + 414, + 545, + 533 + ], + "type": "text", + "content": "Metrics: We follow existing works [34, 5, 29] and use the intersection over union (IoU) averaged over all classes as the main metric (mIoU). Class-wise IoUs are also reported. Comparison against state-of-the-art: Our results are compared with other state-of-the-art approaches on the test set of three datasets in Tab. 1 to 3. We include approaches that use LiDAR only for fair comparison. Notably, our proposed method outperforms all prior works on all three datasets, demonstrating its generalizability across various LiDAR sensors and different geographical regions." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 308, + 535, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 535, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 535, + 545, + 712 + ], + "type": "text", + "content": "Tab. 1 presents a comparison of our approach on the SemanticKITTI multi-scan benchmark, which is designed to evaluate methods that focus on temporal aggregation for semantic segmentation. The other methods in the table are divided into two groups. The first group consists of baselines that are designed for single-scan segmentation but aggregate multiple consecutive frames as input at the cost of higher memory consumption and longer runtime. In contrast, the second group proposes temporal aggregation modules specifically to handle multiple scans. It is worth noting that our proposed method performs significantly better than all of these approaches. MEMORYSEG demonstrates exceptional performance in segmenting dynamic actors, such as moving bicyclist, motorcyclist, and person. These substantial improvements can be attributed to the proposed re" + } + ] + } + ], + "index": 7 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 298, + 750, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 750, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 298, + 750, + 312, + 757 + ], + "type": "text", + "content": "750" + } + ] + } + ], + "index": 8 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 70, + 544, + 156 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 544, + 156 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 544, + 156 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 544, + 156 + ], + "type": "table", + "html": "
MethodmIoUFW-mIoUBarrierBicycleBusCarConstructionMotorcyclePedestrainTraffic ConeTrailerTruckDrivableOther FlatSidewalkTerrainMannmadeVegetation
PolarNet [32]69.487.472.216.877.086.551.169.764.854.169.763.596.667.177.772.187.184.5
Cylinder3D [34]77.289.982.829.884.389.463.079.377.273.484.669.197.770.280.375.590.487.6
SPVCNN [22]77.489.780.030.091.990.864.779.075.670.981.074.697.469.280.076.189.387.1
(AF)2-S3Net [5]78.388.578.952.289.984.277.474.377.372.083.973.897.166.577.574.087.786.8
MEMORYSEG [ours]80.691.484.940.291.292.471.273.585.977.888.076.497.969.081.277.692.689.7
", + "image_path": "e8ba7269a459b7f2f6a7b35233e17fcc9812e455be0b96ff59c317fac47833a1.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 98, + 186, + 494, + 270 + ], + "blocks": [ + { + "bbox": [ + 48, + 157, + 545, + 177 + ], + "lines": [ + { + "bbox": [ + 48, + 157, + 545, + 177 + ], + "spans": [ + { + "bbox": [ + 48, + 157, + 545, + 177 + ], + "type": "text", + "content": "Table 2. Comparison to the state-of-the-art methods on the test set of nuScenes [4] LiDAR semantic segmentation benchmark. We include LiDAR-only published approaches at the time of submission. Metrics are provided in [%]" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 98, + 186, + 494, + 270 + ], + "lines": [ + { + "bbox": [ + 98, + 186, + 494, + 270 + ], + "spans": [ + { + "bbox": [ + 98, + 186, + 494, + 270 + ], + "type": "table", + "html": "
MethodmIoUCarBicycleMotorcycleTruckOther VehiclePersonRoadRoad BarriersSidewalkBuildingVegetationTerrainBackgroundTraffic Sign
SqueezeSegv3 [28]55.792.824.118.036.554.363.091.111.971.386.285.061.363.220.6
SalsaNext [7]57.892.140.731.728.756.269.090.022.667.185.683.458.563.320.6
TemporalLidarSeg [8]60.093.733.638.037.159.972.091.114.670.688.288.463.868.420.7
SPVCNN [22]64.795.838.146.344.074.178.691.228.370.387.287.561.567.535.6
MEMORYSEG [ours]70.397.260.258.462.974.382.692.127.774.189.490.764.972.836.4
", + "image_path": "6111709c4eed82f35fbc00dab61043a0841f87ba0094eaeae26fac40d42846c9.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 92, + 270, + 498, + 280 + ], + "lines": [ + { + "bbox": [ + 92, + 270, + 498, + 280 + ], + "spans": [ + { + "bbox": [ + 92, + 270, + 498, + 280 + ], + "type": "text", + "content": "Table 3. Comparison to the state-of-the-art methods on the test set of PandaSet [27]. Metrics are provided in [%]." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 49, + 290, + 286, + 421 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 290, + 286, + 421 + ], + "spans": [ + { + "bbox": [ + 49, + 290, + 286, + 421 + ], + "type": "text", + "content": "current framework, which implicitly encode the motion of moving actors in the 3D latent memory. Furthermore, we also demonstrate the effectiveness of our approach on the single-scan benchmark of the same dataset. We refer the readers to the supplementary material for the detailed results. This is a more competitive benchmark focusing on single-scan semantic segmentation where previous research has focused on proposing various architectures [5, 29, 34] or knowledge distillation techniques [12]. Our results show that MEMORYSEG can outperform these methods, which are highly optimized for this benchmark." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 424, + 286, + 591 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 424, + 286, + 591 + ], + "spans": [ + { + "bbox": [ + 49, + 424, + 286, + 591 + ], + "type": "text", + "content": "Results on nuScenes [4] benchmark are presented in Tab. 2. MEMORYSEG outperforms the previous state-of-the-art. Our method is particularly effective in smaller classes such as barriers, pedestrians, and traffic cones, which present challenges for semantic segmentation networks due to the sparser point clouds available in this dataset. However, our approach overcomes this limitation by using a 3D latent memory to improve semantic reasoning of the sparse points. Additionally, we observe significant gains in the background classes, such as sidewalk, terrain, and manmade, which often rely on understanding of the surrounding to be segmented correctly. Our method improves the contextual reasoning by accumulating past observations using a latent memory representation." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 594, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 594, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 49, + 594, + 286, + 713 + ], + "type": "text", + "content": "Finally, we compare our results with the state-of-the-art methods on PandaSet [27] and report the test set IoUs in Tab. 3. Our proposed method also achieves state-of-the-art performance in this dataset. Notably, our approach outperforms others by a large margin in almost all classes. We highlight that MEMORYSEG consistently outperforms TemporalLidarSeg [8] across multiple benchmarks, a method that also proposes a latent memory but in RV instead of 3D. These findings confirm our hypothesis that the 3D latent memory approach is more effective than using RV in" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 308, + 290, + 506, + 302 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 290, + 506, + 302 + ], + "spans": [ + { + "bbox": [ + 308, + 290, + 506, + 302 + ], + "type": "text", + "content": "accurately segmenting objects in 3D point clouds." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 307, + 307, + 544, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 307, + 544, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 307, + 544, + 712 + ], + "type": "text", + "content": "Importance of the memory: Fig. 4 highlights the significance of incorporating memory, particularly in longer range regions where point clouds are much sparser. To assess the effectiveness of the learned latent memory, we compare against our encoder and decoder without the memory update module as the single frame baseline (SFB). Our proposed network consistently outperforms the SFB in all regions, with the most significant improvement observed in the long-range region of nuScenes, where points are sparser and more difficult to contextualize. Thanks to the 3D sparse latent memory that accumulates semantic embeddings of past frames, our proposed approach performs much better than the SFB, particularly in those challenging regions. Fig. 5 provides similar insights. In the top-left of the figure, the SFB fails to segment a partially occluded vehicle located behind a fence. In contrast, our proposed approach initially segments the vehicle as other vehicle class, but as the ego vehicle advances, the 3D latent memory accumulates and refines through new observations, enabling the network to correctly identify the vehicle as a car after two sweeps. This illustration further confirms that the proposed 3D latent memory provides better contextualization of sparse objects that are partially occluded. Additional qualitative results are provided in the supplementary materials. We also quantitatively demonstrate the importance of memory in Tab. 4. M1 builds on SFB and incorporates FAM and MRM. Note that both FAM and MRM are essential for updating the latent memory continuously. FAM aligns the sparse 3D latent memory in the traveling ego frame, while MRM helps in learning to reset and update the memory recurrently. APM is replaced with zero-padding in M1 to highlight the significance of memory. M1 shows a " + }, + { + "bbox": [ + 307, + 307, + 544, + 712 + ], + "type": "inline_equation", + "content": "2.3\\%" + }, + { + "bbox": [ + 307, + 307, + 544, + 712 + ], + "type": "text", + "content": " improvement in the mIoU metric compared to SFB, attributed to the ability of the sparse 3D latent memory to aggregate information in the" + } + ] + } + ], + "index": 8 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 298, + 750, + 311, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 750, + 311, + 757 + ], + "spans": [ + { + "bbox": [ + 298, + 750, + 311, + 757 + ], + "type": "text", + "content": "751" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 72, + 138, + 144 + ], + "blocks": [ + { + "bbox": [ + 53, + 72, + 138, + 144 + ], + "lines": [ + { + "bbox": [ + 53, + 72, + 138, + 144 + ], + "spans": [ + { + "bbox": [ + 53, + 72, + 138, + 144 + ], + "type": "image", + "image_path": "c348a92562f83dc6f81a722b53334aa51d91ac4d8133d3b32cbc9ff1f36538cf.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 148, + 286, + 169 + ], + "lines": [ + { + "bbox": [ + 47, + 148, + 286, + 169 + ], + "spans": [ + { + "bbox": [ + 47, + 148, + 286, + 169 + ], + "type": "text", + "content": "Figure 4. Comparison of MEMORYSEG with single frame baseline (SFB) on the validation set with different distance-range." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 139, + 72, + 198, + 144 + ], + "blocks": [ + { + "bbox": [ + 139, + 72, + 198, + 144 + ], + "lines": [ + { + "bbox": [ + 139, + 72, + 198, + 144 + ], + "spans": [ + { + "bbox": [ + 139, + 72, + 198, + 144 + ], + "type": "image", + "image_path": "16a254d4d06ebc9e4d62b15bcb503d1ffa68b8f04d1226febbd8f6da7be64b03.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 198, + 72, + 281, + 144 + ], + "blocks": [ + { + "bbox": [ + 198, + 72, + 281, + 144 + ], + "lines": [ + { + "bbox": [ + 198, + 72, + 281, + 144 + ], + "spans": [ + { + "bbox": [ + 198, + 72, + 281, + 144 + ], + "type": "image", + "image_path": "a9b38dbbd4ac12da2f32f0361b8bf1bc03c879777c81cefdd4f2d2537f42021d.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 50, + 175, + 286, + 308 + ], + "blocks": [ + { + "bbox": [ + 50, + 175, + 286, + 308 + ], + "lines": [ + { + "bbox": [ + 50, + 175, + 286, + 308 + ], + "spans": [ + { + "bbox": [ + 50, + 175, + 286, + 308 + ], + "type": "image", + "image_path": "c36b96394e07a95ad5a8dc2679eb6408d10ed23e71334877732f3c8e4fe54fd7.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 312, + 286, + 345 + ], + "lines": [ + { + "bbox": [ + 46, + 312, + 286, + 345 + ], + "spans": [ + { + "bbox": [ + 46, + 312, + 286, + 345 + ], + "type": "text", + "content": "Figure 5. Predictions of MEMORYSEG over time are illustrated in the bottom row. We include the prediction from the single frame baseline (SFB) and ground truth with color code at the top." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 369, + 275, + 381 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 369, + 275, + 381 + ], + "spans": [ + { + "bbox": [ + 47, + 369, + 275, + 381 + ], + "type": "text", + "content": "temporal dimension as the ego moves through the scene." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 385, + 287, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 385, + 287, + 613 + ], + "spans": [ + { + "bbox": [ + 46, + 385, + 287, + 613 + ], + "type": "text", + "content": "Influence of adaptive padding: In this section, we compare our proposed APM with zero padding and Continuous Conv [25]. The results are presented in Tab. 4. M2 is an extension of M1 that introduces adaptive padding on both observation and memory embeddings when they are aligned. However, the padded entries are only processed using the relative coordinates in the neighborhood, similar to Continuous Conv [25] with the attention mechanism. A slight improvement of " + }, + { + "bbox": [ + 46, + 385, + 287, + 613 + ], + "type": "inline_equation", + "content": "0.2\\%" + }, + { + "bbox": [ + 46, + 385, + 287, + 613 + ], + "type": "text", + "content": " is observed when new observations in the latent memory are initialized with a learned guess instead of all zeros. To further improve the performance of the network, M4 exploits feature similarities and distances in APM. When assigning an initial embedding to a new entry, both the relative position and the similarity to neighbors are considered. This is particularly useful for moving actors in the scene, where the network should learn to start with a guess with a similar embedding in the neighborhood, rather than the closest entry. By comparing M0 with M3 further confirms the usefulness of the proposed APM." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 617, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 617, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 617, + 286, + 713 + ], + "type": "text", + "content": "Influence of memory refinement: In M3 of Tab. 4, we replace our proposed MRM with a vanilla sparse ConvGRU [1], which has a limited receptive field due to the convolution kernel size, making it challenging for fast-moving actors. However, MRM overcomes this limitation by down-sampling features to increase the receptive field. This improves the learning of meaningful reset and update gates for refining the latent memory." + } + ] + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 316, + 70, + 537, + 157 + ], + "blocks": [ + { + "bbox": [ + 316, + 70, + 537, + 157 + ], + "lines": [ + { + "bbox": [ + 316, + 70, + 537, + 157 + ], + "spans": [ + { + "bbox": [ + 316, + 70, + 537, + 157 + ], + "type": "table", + "html": "
FAMAPMMRMmIoU
CCOursSCGOurs
SFB67.2
M0✓✓✓68.9
M1✓✓69.5
M2✓✓✓69.7
M3✓✓✓69.7
M4✓✓✓70.8
", + "image_path": "bfe8fa4fe7101edbdd298074a4c3da923108eb77d02dc92672762282aa0a42de.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "type": "table", + "bbox": [ + 326, + 222, + 526, + 256 + ], + "blocks": [ + { + "bbox": [ + 305, + 157, + 545, + 212 + ], + "lines": [ + { + "bbox": [ + 305, + 157, + 545, + 212 + ], + "spans": [ + { + "bbox": [ + 305, + 157, + 545, + 212 + ], + "type": "text", + "content": "Table 4. Ablation on the proposed components in the network. Metrics are mIoU on the validation set of SemanticKITTI [2] provided in [%]. FAM: Feature Alignment Module, APM: Adaptive Padding Module, CC: padding using Continuous Conv [25], SCG: Sparse ConvGRU [1]. MRM: Memory Refinement Module." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 326, + 222, + 526, + 256 + ], + "lines": [ + { + "bbox": [ + 326, + 222, + 526, + 256 + ], + "spans": [ + { + "bbox": [ + 326, + 222, + 526, + 256 + ], + "type": "table", + "html": "
RegularizerSemanticKITTInuScenesPandaSet
66.472.964.7
✓67.276.766.6
", + "image_path": "70a5c83324a4c2969d722ae9f5bab487551481b00150b5939b114caaf40204e5.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 264, + 545, + 297 + ], + "lines": [ + { + "bbox": [ + 305, + 264, + 545, + 297 + ], + "spans": [ + { + "bbox": [ + 305, + 264, + 545, + 297 + ], + "type": "text", + "content": "Table 5. Ablation on the model performance with and without the proposed regularizer. Metrics are mIoU on the validation set provided in [%]." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 308, + 545, + 426 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 308, + 545, + 426 + ], + "spans": [ + { + "bbox": [ + 304, + 308, + 545, + 426 + ], + "type": "text", + "content": "Influence of the regularizer: To demonstrate the effectiveness of our regularizer to train semantic segmentation networks on point clouds with different characteristics, we ablate this loss on the three datasets and summarize the results in Tab. 5. The results consistently show that incorporating the regularizer leads to performance improvements. The regularizer provides additional supervision on variations and boundaries, which is particularly beneficial for nuScenes. We note once again that this dataset has sparser point clouds than the other two." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 430, + 545, + 525 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 430, + 545, + 525 + ], + "spans": [ + { + "bbox": [ + 304, + 430, + 545, + 525 + ], + "type": "text", + "content": "Parameter count and runtime comparison: MEMORY-SEG incurs only a relatively small computational overhead of " + }, + { + "bbox": [ + 304, + 430, + 545, + 525 + ], + "type": "inline_equation", + "content": "23\\%" + }, + { + "bbox": [ + 304, + 430, + 545, + 525 + ], + "type": "text", + "content": " more parameters and " + }, + { + "bbox": [ + 304, + 430, + 545, + 525 + ], + "type": "inline_equation", + "content": "20\\%" + }, + { + "bbox": [ + 304, + 430, + 545, + 525 + ], + "type": "text", + "content": " runtime than SFB. On the other hand, when naively concatenating the past five frames as the input to the model, despite having the same number of parameters as SFB, it takes 1.58 times longer (32% slower than our method) while only exploiting a limited 0.5-second window from the past." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 537, + 378, + 549 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 537, + 378, + 549 + ], + "spans": [ + { + "bbox": [ + 306, + 537, + 378, + 549 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 558, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 545, + 713 + ], + "type": "text", + "content": "In this paper, we have proposed a novel online LiDAR segmentation model named MEMORYSEG, which utilizes a sparse 3D latent memory to recurrently accumulate learned semantic embeddings from past observations. We also presented a novel variation regularizer to supervise the learning of 3D semantic segmentation on point clouds. Our results demonstrate that our approach achieve state-of-the-art performance on three large-scale datasets. This improved performance can be attributed to the ability of the latent memory to better contextualize objects in the scene. Looking ahead, our future work will focus on integrating instance segmentation and tracking to develop an end-to-end memory-augmented panoptic segmentation framework." + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 297, + 749, + 312, + 757 + ], + "type": "text", + "content": "752" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 147 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 147 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 147 + ], + "type": "text", + "content": "[1] Nicolas Ballas, Li Yao, Chris Pal, and Aaron C. Courville. Delving deeper into convolutional networks for learning video representations. In 4th International Conference on Learning Representations, ICLR 2016, San Juan, Puerto Rico, May 2-4, 2016, Conference Track Proceedings, 2016." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 148, + 288, + 203 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 148, + 288, + 203 + ], + "spans": [ + { + "bbox": [ + 53, + 148, + 288, + 203 + ], + "type": "text", + "content": "[2] Jens Behley, Martin Garbade, Andres Milioto, Jan Quenzel, Sven Behnke, Cyril Stachniss, and Jürgen Gall. Semantickitti: A dataset for semantic scene understanding of lidar sequences. In 2019 IEEE/CVF International Conference on Computer Vision, pages 9296-9306. IEEE, 2019." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 205, + 288, + 270 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 205, + 288, + 270 + ], + "spans": [ + { + "bbox": [ + 53, + 205, + 288, + 270 + ], + "type": "text", + "content": "[3] Maxim Berman, Amal Rannen Triki, and Matthew B Blaschko. The lovasz-softmax loss: A tractable surrogate for the optimization of the intersection-over-union measure in neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 4413-4421, 2018." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 272, + 287, + 338 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 272, + 287, + 338 + ], + "spans": [ + { + "bbox": [ + 53, + 272, + 287, + 338 + ], + "type": "text", + "content": "[4] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11621-11631, 2020." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 340, + 287, + 406 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 340, + 287, + 406 + ], + "spans": [ + { + "bbox": [ + 53, + 340, + 287, + 406 + ], + "type": "text", + "content": "[5] Ran Cheng, Ryan Razani, Ehsan Taghavi, Enxu Li, and Bingbing Liu. af2-s3net: Attentive feature fusion with adaptive feature selection for sparse semantic segmentation network. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 12547-12556, 2021." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 407, + 287, + 462 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 407, + 287, + 462 + ], + "spans": [ + { + "bbox": [ + 53, + 407, + 287, + 462 + ], + "type": "text", + "content": "[6] Christopher Choy, JunYoung Gwak, and Silvio Savarese. 4d spatio-temporal convnets: Minkowski convolutional neural networks. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 3075-3084, 2019." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 464, + 287, + 509 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 464, + 287, + 509 + ], + "spans": [ + { + "bbox": [ + 53, + 464, + 287, + 509 + ], + "type": "text", + "content": "[7] Tiago Cortinhal, George Tzelepis, and Eren Erdal Aksoy. Salsanext: Fast semantic segmentation of lidar point clouds for autonomous driving. In 2020 IEEE Intelligent Vehicles Symposium (IV), pages 655-661, 2020." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 510, + 287, + 564 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 510, + 287, + 564 + ], + "spans": [ + { + "bbox": [ + 53, + 510, + 287, + 564 + ], + "type": "text", + "content": "[8] Fabian Duerr, Mario Pfaller, Hendrik Weigel, and Jürgen Beyerer. Lidar-based recurrent 3d semantic segmentation with temporal memory alignment. In 2020 International Conference on 3D Vision (3DV), pages 781-790. IEEE, 2020." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 567, + 287, + 633 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 567, + 287, + 633 + ], + "spans": [ + { + "bbox": [ + 53, + 567, + 287, + 633 + ], + "type": "text", + "content": "[9] Davi Frossard, Shun Da Suo, Sergio Casas, James Tu, and Raquel Urtasun. Strobe: Streaming object detection from lidar packets. In Jens Kober, Fabio Ramos, and Claire Tomlin, editors, Proceedings of the 2020 Conference on Robot Learning, volume 155 of Proceedings of Machine Learning Research, pages 1174-1183. PMLR, 16-18 Nov 2021." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 635, + 287, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 635, + 287, + 678 + ], + "spans": [ + { + "bbox": [ + 48, + 635, + 287, + 678 + ], + "type": "text", + "content": "[10] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the kitti vision benchmark suite. In Conference on Computer Vision and Pattern Recognition (CVPR), 2012." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 680, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 680, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 680, + 287, + 713 + ], + "type": "text", + "content": "[11] Martin Gerdzhev, Ryan Razani, Ehsan Taghavi, and Liu Bingbing. Tornado-net: multiview total variation semantic segmentation with diamond inception module. In 2021" + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 27, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 95 + ], + "type": "text", + "content": "IEEE International Conference on Robotics and Automation (ICRA), pages 9543-9549, 2021." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 308, + 95, + 545, + 148 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 95, + 545, + 148 + ], + "spans": [ + { + "bbox": [ + 308, + 95, + 545, + 148 + ], + "type": "text", + "content": "[12] Yuenan Hou, Xinge Zhu, Yuexin Ma, Chen Change Loy, and Yikang Li. Point-to-voxel knowledge distillation for lidar semantic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8479-8488, 2022." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 308, + 150, + 545, + 215 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 150, + 545, + 215 + ], + "spans": [ + { + "bbox": [ + 308, + 150, + 545, + 215 + ], + "type": "text", + "content": "[13] Qingyong Hu, Bo Yang, Linhai Xie, Stefano Rosa, Yulan Guo, Zhihua Wang, Niki Trigoni, and Andrew Markham. Randla-net: Efficient semantic segmentation of large-scale point clouds. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 11108-11117, 2020." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 217, + 545, + 237 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 217, + 545, + 237 + ], + "spans": [ + { + "bbox": [ + 308, + 217, + 545, + 237 + ], + "type": "text", + "content": "[14] Ian Jolliffe. *Principal Component Analysis*. John Wiley & Sons, Ltd, 2005." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 239, + 545, + 282 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 239, + 545, + 282 + ], + "spans": [ + { + "bbox": [ + 308, + 239, + 545, + 282 + ], + "type": "text", + "content": "[15] Andres Milioto, Ignacio Vizzo, Jens Behley, and Cyril Stachniss. Rangenet++: Fast and accurate lidar semantic segmentation. In Proc. of the IEEE/RSJ Intl. Conf. on Intelligent Robots and Systems (IROS), 2019." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 283, + 545, + 327 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 283, + 545, + 327 + ], + "spans": [ + { + "bbox": [ + 308, + 283, + 545, + 327 + ], + "type": "text", + "content": "[16] Charles R Qi, Hao Su, Kaichun Mo, and Leonidas J Guibas. Pointnet: Deep learning on point sets for 3d classification and segmentation. In Proc. of the IEEE conference on computer vision and pattern recognition, pages 652-660, 2017." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 327, + 545, + 371 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 327, + 545, + 371 + ], + "spans": [ + { + "bbox": [ + 308, + 327, + 545, + 371 + ], + "type": "text", + "content": "[17] Charles Ruizhongtai Qi, Li Yi, Hao Su, and Leonidas J Guibas. Pointnet++: Deep hierarchical feature learning on point sets in a metric space. Advances in neural information processing systems, 30, 2017." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 372, + 545, + 437 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 372, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 308, + 372, + 545, + 437 + ], + "type": "text", + "content": "[18] Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-net: Convolutional networks for biomedical image segmentation. In Medical Image Computing and Computer-Assisted Intervention-MICCAI 2015: 18th International Conference, Munich, Germany, October 5-9, 2015, Proceedings, Part III 18, pages 234-241. Springer, 2015." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 438, + 545, + 480 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 438, + 545, + 480 + ], + "spans": [ + { + "bbox": [ + 308, + 438, + 545, + 480 + ], + "type": "text", + "content": "[19] Peer Schütt, Radu Alexandru Rosu, and Sven Behnke. Abstract flow for temporal semantic segmentation on the permutohedral lattice. In Proceedings of the IEEE International Conference on Robotics and Automation (ICRA), 2022." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 482, + 545, + 536 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 482, + 545, + 536 + ], + "spans": [ + { + "bbox": [ + 308, + 482, + 545, + 536 + ], + "type": "text", + "content": "[20] Hanyu Shi, Guosheng Lin, Hao Wang, Tzu-Yi Hung, and Zhenhua Wang. Spsequencenet: Semantic segmentation network on 4d point clouds. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 4574-4583, 2020." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 537, + 545, + 579 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 537, + 545, + 579 + ], + "spans": [ + { + "bbox": [ + 308, + 537, + 545, + 579 + ], + "type": "text", + "content": "[21] Haotian Tang, Zhijian Liu, Xiuyu Li, Yujun Lin, and Song Han. Torchsparse: Efficient point cloud inference engine. Proceedings of Machine Learning and Systems, 4:302-315, 2022." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 581, + 545, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 581, + 545, + 646 + ], + "spans": [ + { + "bbox": [ + 308, + 581, + 545, + 646 + ], + "type": "text", + "content": "[22] Haotian Tang, Zhijian Liu, Shengyu Zhao, Yujun Lin, Ji Lin, Hanrui Wang, and Song Han. Searching efficient 3d architectures with sparse point-voxel convolution. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23–28, 2020, Proceedings, Part XXVIII, pages 685–702. Springer, 2020." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 647, + 545, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 647, + 545, + 690 + ], + "spans": [ + { + "bbox": [ + 308, + 647, + 545, + 690 + ], + "type": "text", + "content": "[23] Maxim Tatarchenko, Jaesik Park, Vladlen Koltun, and Qian-Yi Zhou. Tangent convolutions for dense prediction in 3d. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3887-3896, 2018." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 692, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 692, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 692, + 545, + 713 + ], + "type": "text", + "content": "[24] Hugues Thomas, Charles R Qi, Jean-Emmanuel Deschaud, Beatrix Marcotegui, François Goulette, and Leonidas J" + } + ] + } + ], + "index": 26 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "type": "text", + "content": "753" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 685 + ], + "type": "list", + "angle": 0, + "index": 11, + "blocks": [ + { + "bbox": [ + 67, + 72, + 287, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 287, + 106 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 287, + 106 + ], + "type": "text", + "content": "Guibas. Kpconv: Flexible and deformable convolution for point clouds. In Proc. of the IEEE International Conference on Computer Vision, pages 6411-6420, 2019." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 287, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 287, + 162 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 287, + 162 + ], + "type": "text", + "content": "[25] Shenlong Wang, Simon Suo, Wei-Chiu Ma, Andrei Pokrovsky, and Raquel Urtasun. Deep parametric continuous convolutional neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2589-2597, 2018." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 163, + 287, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 163, + 287, + 206 + ], + "spans": [ + { + "bbox": [ + 49, + 163, + 287, + 206 + ], + "type": "text", + "content": "[26] Song Wang, Jianke Zhu, and Ruixiang Zhang. Metarangeseg: Lidar sequence semantic segmentation using multiple feature aggregation. IEEE Robotics and Automation Letters, 7(4):9739-9746, 2022." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 208, + 287, + 272 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 208, + 287, + 272 + ], + "spans": [ + { + "bbox": [ + 49, + 208, + 287, + 272 + ], + "type": "text", + "content": "[27] Pengchuan Xiao, Zhenlei Shao, Steven Hao, Zishuo Zhang, Xiaolin Chai, Judy Jiao, Zesong Li, Jian Wu, Kai Sun, Kun Jiang, et al. Pandaset: Advanced sensor suite dataset for autonomous driving. In 2021 IEEE International Intelligent Transportation Systems Conference (ITSC), pages 3095-3101. IEEE, 2021." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 274, + 287, + 329 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 274, + 287, + 329 + ], + "spans": [ + { + "bbox": [ + 49, + 274, + 287, + 329 + ], + "type": "text", + "content": "[28] Chenfeng Xu, Bichen Wu, Zining Wang, Wei Zhan, Peter Vajda, Kurt Keutzer, and Masayoshi Tomizuka. Squeeze-segv3: Spatially-adaptive convolution for efficient pointcloud segmentation. In European Conference on Computer Vision, pages 1-19. Springer, 2020." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 331, + 287, + 384 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 331, + 287, + 384 + ], + "spans": [ + { + "bbox": [ + 49, + 331, + 287, + 384 + ], + "type": "text", + "content": "[29] Jianyun Xu, Ruixiang Zhang, Jian Dou, Yushi Zhu, Jie Sun, and Shiliang Pu. Rpvnet: A deep and efficient range-point-voxel fusion network for lidar point cloud segmentation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 16024-16033, 2021." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 386, + 287, + 441 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 386, + 287, + 441 + ], + "spans": [ + { + "bbox": [ + 49, + 386, + 287, + 441 + ], + "type": "text", + "content": "[30] Xu Yan, Jiantao Gao, Chaoda Zheng, Chao Zheng, Ruimao Zhang, Shuguang Cui, and Zhen Li. 2dpass: 2d priors assisted semantic segmentation on lidar point clouds. In European Conference on Computer Vision, pages 677-695. Springer, 2022." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 442, + 287, + 495 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 442, + 287, + 495 + ], + "spans": [ + { + "bbox": [ + 49, + 442, + 287, + 495 + ], + "type": "text", + "content": "[31] Maosheng Ye, Shuangjie Xu, Tongyi Cao, and Qifeng Chen. Drinet: A dual-representation iterative learning network for point cloud segmentation. In Proceedings of the IEEE/CVF international conference on computer vision, pages 7447-7456, 2021." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 498, + 287, + 563 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 498, + 287, + 563 + ], + "spans": [ + { + "bbox": [ + 49, + 498, + 287, + 563 + ], + "type": "text", + "content": "[32] Yang Zhang, Zixiang Zhou, Philip David, Xiangyu Yue, Zerong Xi, Boqing Gong, and Hassan Foroosh. Polarnet: An improved grid representation for online lidar point clouds semantic segmentation. In Proc. of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9601-9610, 2020." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 564, + 287, + 618 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 564, + 287, + 618 + ], + "spans": [ + { + "bbox": [ + 49, + 564, + 287, + 618 + ], + "type": "text", + "content": "[33] Zixiang Zhou, Yang Zhang, and Hassan Foroosh. Panoptic-polarnet: Proposal-free lidar point cloud panoptic segmentation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13194-13203, 2021." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 620, + 287, + 685 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 620, + 287, + 685 + ], + "spans": [ + { + "bbox": [ + 49, + 620, + 287, + 685 + ], + "type": "text", + "content": "[34] Xinge Zhu, Hui Zhou, Tai Wang, Fangzhou Hong, Yuexin Ma, Wei Li, Hongsheng Li, and Dahua Lin. Cylindrical and asymmetrical 3d convolution networks for lidar segmentation. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 9939-9948, 2021." + } + ] + } + ], + "index": 10 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "spans": [ + { + "bbox": [ + 298, + 749, + 312, + 757 + ], + "type": "text", + "content": "754" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/743afd5f-14b2-4965-bbeb-bded0a673761_content_list.json b/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/743afd5f-14b2-4965-bbeb-bded0a673761_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..2a5fc9096583d8c25031291f676a721e8522e174 --- /dev/null +++ b/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/743afd5f-14b2-4965-bbeb-bded0a673761_content_list.json @@ -0,0 +1,1623 @@ +[ + { + "type": "text", + "text": "Mesh2Tex: Generating Mesh Textures from Image Queries", + "text_level": 1, + "bbox": [ + 187, + 130, + 782, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Alexey Bokhovkin \nTechnical University of Munich", + "bbox": [ + 217, + 181, + 470, + 215 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "aleksei.bokhovkin@tum.de", + "bbox": [ + 236, + 219, + 452, + 232 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Shubham Tulsiani \nCarnegie Mellon University", + "bbox": [ + 527, + 181, + 750, + 215 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "shubhtuls@cmu.edu", + "bbox": [ + 563, + 219, + 715, + 232 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Angela Dai \nTechnical University of Munich", + "bbox": [ + 357, + 242, + 611, + 276 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "angela.dai@tum.de", + "bbox": [ + 408, + 280, + 560, + 292 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/8296feaf5e377ed5113e2fbd562fd59894a85601a47335c82e8d3b0376f2da5b.jpg", + "image_caption": [ + "Figure 1: Mesh2Tex learns realistic object texturing on a shape geometry through a hybrid mesh-field texture representation supporting high-resolution texture generation on various shape meshes. Furthermore, our learned texture manifold supports texture transfer optimization from image queries without requiring any matching geometry or pose alignment to the image, producing perceptually consistent texturing in this challenging content creation scenario." + ], + "image_footnote": [], + "bbox": [ + 114, + 301, + 282, + 611 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/98d115b7600e4fcc1169744912728cc1f28829d3c0b434b74110962a9cac1e34.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 300, + 301, + 566, + 612 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/20262dff57895213672ea8064178813438175c32c8762a14990a3dc55c11c4be.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 586, + 301, + 852, + 612 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 686, + 313, + 702 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Remarkable advances have been achieved recently in learning neural representations that characterize object geometry, while generating textured objects suitable for downstream applications and 3D rendering remains at an early stage. In particular, reconstructing textured geometry from images of real objects is a significant challenge – reconstructed geometry is often inexact, making realistic texturing a significant challenge. We present Mesh2Tex, which learns a realistic object texture manifold from uncorrelated collections of 3D object geometry and photorealistic RGB images, by leveraging a hybrid mesh-neural-field texture representation. Our texture representation enables compact encoding", + "bbox": [ + 75, + 719, + 473, + 902 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "of high-resolution textures as a neural field in the barycentric coordinate system of the mesh faces. The learned texture manifold enables effective navigation to generate an object texture for a given 3D object geometry that matches to an input RGB image, which maintains robustness even under challenging real-world scenarios where the mesh geometry approximates an inexact match to the underlying geometry in the RGB image. Mesh2Tex can effectively generate realistic object textures for an object mesh to match real images observations towards digitization of real environments, significantly improving over previous state of the art.", + "bbox": [ + 496, + 688, + 893, + 853 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Project page: alexeybokhovkin.github.io/ mesh2tex/", + "bbox": [ + 498, + 854, + 893, + 883 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "8918", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 78, + 90, + 207, + 104 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The ability to obtain 3D representations of real-world objects lies at the core of many important applications in graphics, robotics, movies and video games, and mixed reality. Approaches tackling the tasks of 3D generation [33, 26, 21, 29, 30, 10] or single-view reconstruction [5, 27, 46, 25, 7] enable users to easily create digital 3D assets, either from scratch or conditioned on an image. However, these approaches primarily focus on generating/inferring the geometry of objects, and this alone is insufficient to capture realistic environments, which requires high-quality texturing.", + "bbox": [ + 76, + 114, + 468, + 280 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this work, we propose Mesh2Tex tackle the complementary task of high-fidelity texture generation given known object geometry. In addition to allowing texturing generation for a given object mesh, Mesh2Tex also enables image-based texture synthesis – synthesizing textures that perceptually match a single RGB image observation. In contrast to existing appearance modeling works that characterize texture as a field over the volume of 3D space [3, 39, 40, 31], we observe that object textures lie on object surfaces, and instead generate textures only on the mesh surface, with a hybrid explicit-implicit texture representation that ties the texture field to the barycentric coordinates of the mesh faces. This produces textured meshes directly compatible with downstream applications and 3D rendering engines.", + "bbox": [ + 76, + 281, + 470, + 492 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "As large quantities of high-quality textured 3D objects are very expensive to obtain, requiring countless hours of skilled artists' work, we train our texture generator with uncorrelated collections of 3D object geometry and photorealistic 2D images, leveraging differentiable rendering to optimize mesh textures at arbitrary resolutions to match the quality of real 2D images in an adversarial fashion. That is, we generate coarse features and colors for each mesh face, which are then refined to high-resolution textures through a neural field defined on the barycentric coordinates of each mesh face. This hybrid texture representation enables differentiable rendering for texturing on explicit mesh surfaces while exploiting the efficiency of neural field representations.", + "bbox": [ + 76, + 493, + 470, + 688 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Our learned texture generator can then be used to produce realistic textures to match an input RGB observation of an object, by optimizing over our learned texture manifold conditioned on the mesh geometry, to find a latent texturing that perceptually matches the RGB image. As state-of-the-art object geometry reconstructions are typically inexact (e.g., noise, oversmoothing, retrieval from a database), our learned texture manifold enables effective regularization over plausible textures which effectively capture the perceptual input while providing realistic texturing over the full object. We formulate a patch-based style loss to capture perceptual similarities between our optimized texture and the RGB image, guided by dense correspondence prediction to correlate them. Experiments demonstrate that we outperform state of the art", + "bbox": [ + 76, + 688, + 470, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "in both unconditional texture generation as well as image-conditioned texture generation.", + "bbox": [ + 498, + 90, + 893, + 119 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In summary, our contributions are:", + "bbox": [ + 519, + 122, + 750, + 136 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- a new hybrid mesh-neural-field texture representation that enables diverse, realistic texture generation on object mesh geometry by tying a neural texture field to the barycentric coordinate system of the mesh faces. This enables learning a rich texture manifold from collections of uncorrelated real images and object meshes through adversarial differentiable rendering.", + "- our learned texture manifold enables effective inference-time optimization to texture an object mesh to perceptually match a single real-world RGB image; crucially, we maintain robustness to real-world scenarios of differing views and even geometry with a patch-based perceptual optimization guided by dense correspondences." + ], + "bbox": [ + 517, + 148, + 893, + 354 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 371, + 640, + 386 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Optimization-based Texturing. Various approaches have been proposed to texture 3D shapes by optimizing from aligned image views of the shape. The traditional optimization approach of Zhou et. al. [52] solves a global optimization for a mapping from observed RGB images onto reconstructed geometry. More recently, Huang et. al. [17] introduce a modern adversarial discriminator loss, coupled with differentiable rendering, to optimize for texture on reconstructed geometry to produce realistic texturing robust to camera pose misalignments in real-world RGB-D capture scenarios. PointNeRF [47] and NeuMesh [48] optimize for view-dependent features using distance-based interpolation from the k-nearest neighbor points/vertices; in contrast, we aim to design a method with view-independent texturing that enables robustness to entirely arbitrary viewpoints. While these methods can produce impressive texturing results, they require aligned 2D/3D data and cannot produce textures in unobserved regions.", + "bbox": [ + 496, + 396, + 893, + 669 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Learned Texture Completion and Generation. Learning-based methods have also explored generative texturing, aiming to learn generalized features for unconditional synthesis or conditional inpainting. Photoshop [34] proposes to learn material retrieval to apply materials to 3D shapes. Recently, several methods have been developed to generate textures on various representations: SPSG [9] produces per-voxel colors with an adversarial differentiable rendering formulation, Pavollo et. al. [35] learn texturing in the UV domain, and Henderson et. al. [15] and Texturify [42] propose to generate per-face mesh colors with variational and adversarial training, respectively. TM-NET [12] is basically the 2D approach for texture generation as it uses unfolded UV maps as the main representation, which is unable to generate", + "bbox": [ + 496, + 689, + 893, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "8919", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/b93da614410658cc6da2d5347b5a0be0f60fc03da525c3f744d018db1c5de053.jpg", + "image_caption": [ + "Figure 2: Method overview. Left: we first learn a texture generator for textures represented as a shared local neural field in the barycentric coordinate system of each mesh face. This enables the capture of high-resolution texture detail, while remaining tied to surface geometry, avoiding ambiguities of volumetric field representations. Our learned texture manifold can then be used for texture transfer from a single RGB query image, based on a correspondence-guided patch-based style loss to produce perceptually consistent texturing even for shapes with differing geometry and unknown image pose." + ], + "image_footnote": [], + "bbox": [ + 81, + 89, + 589, + 250 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/fc629d3f54baabbaa5c6e717438f3d2aae02cc57e8dfed2a00e8d297068382d6.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 591, + 90, + 887, + 250 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "consistent textures near the seams. Moreover, this method uses explicit part information, which significantly simplifies the setup for geometry-aware texture generation. The recent success of neural implicit field representations has also inspired implicit texture field models [32, 3, 11]. Our approach aims to model texture on the surface of a mesh, coupled with the representation capacity of a shared implicit field per mesh face.", + "bbox": [ + 75, + 376, + 472, + 498 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Query-based 3D Understanding. The recent success of vision-language models such as CLIP [36] has sparked interest in query-guided 3D understanding from text and images. Text and image guidance have been exploited for knowledge distillation for 3D semantic understanding [24, 38, 20]. Various shape generation tasks have also been formulated with text queries, by leveraging CLIP as supervision [41, 19, 44]. In particular, Text2Mesh [28] leverages CLIP guidance for text-based texture optimization on 3D shapes. We formulate Mesh2Tex to support image-based queries for texture transfer optimization to various 3D shapes, to reflect potential practical texturing scenarios where images are largely easy to capture or find, with high visual specificity. We thus tackle challenges in geometric and pose misalignments from various potential image queries.", + "bbox": [ + 75, + 518, + 472, + 744 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Method", + "text_level": 1, + "bbox": [ + 76, + 760, + 169, + 776 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Overview", + "text_level": 1, + "bbox": [ + 76, + 785, + 187, + 800 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We aim to learn a high-quality texture manifold conditioned on a given shape mesh geometry, which supports unconditional texture generation as well as optimization within the texture manifold to fit to image queries for practical texturing scenarios. An overview of our approach is visualized in Figure 2. We propose to learn this texture manifold on a", + "bbox": [ + 75, + 809, + 472, + 901 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "hybrid representation that combines a mesh representation with a neural field operating on the barycentric coordinates of each mesh face. Our texture generator then generates initial coarse features per-face for a given shape mesh, which are then refined by a shared neural field across the mesh faces. This enables high-resolution texture generation by sampling the neural field on the mesh surface. In the absence of a large-scale dataset of high-quality 3D textured shapes, we supervise the texture generation with an adversarial loss with photorealistic 2D images, through differentiable rendering.", + "bbox": [ + 496, + 376, + 893, + 527 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We can then traverse our learned texture manifold to generate textures for a given shape geometry to perceptually match to image queries. Since an RGB image query may be taken at an arbitrary camera pose, we estimate the object pose in the RGB image along with its normalized object coordinates [45] to guide the texture optimization. Furthermore, we must also support texture transfer scenarios, as having an exact geometric shape match for an arbitrary RGB image query cannot be assumed in practice. We thus employ both a global and local patch-based style loss to generate a realistic texture that perceptually matches the query image.", + "bbox": [ + 496, + 527, + 895, + 696 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Mesh-Field Texture Generation", + "text_level": 1, + "bbox": [ + 500, + 708, + 779, + 723 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We learn a texture manifold on a mesh-field representation. Given a shape mesh $\\mathcal{M}$ , we use a latent-variable conditioned encoder-decoder to obtain per-face features $F$ . We then employ a shared neural field $\\psi$ that operates on each face to produce arbitrary-resolution texturing. High-quality texture generation is then learned by supervision with photorealistic 2D images in an adversarial fashion through differentiable rendering. Our texture generator training is shown in Figure 3.", + "bbox": [ + 496, + 732, + 893, + 868 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "A shape mesh $\\mathcal{M}$ is represented as a quadrilateral mesh; inspired by the hierarchical mesh representation of Textu", + "bbox": [ + 498, + 869, + 893, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "8920", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "rify [42], we also employ QuadriFlow [18] to parameterize shape meshes as hierarchies of 4-way rotationally symmetric (4-RoSy) fields. We can then leverage convolutional and pooling operators on the neighborhoods of each quad face, enabling encoding and decoding features on such mesh faces with arbitrary topologies. We employ an encoder-decoder face convolutional network $G$ on $\\mathcal{M}$ , which takes as input geometric quad face features (per-face normals, fundamental forms, and curvature), and predicts per-face features $F_{c}$ . Similar to StyleGAN [22] we incorporate a latent texture code $z$ into the decoder through a mapping network.", + "bbox": [ + 75, + 90, + 472, + 257 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "As we aim to generate high-quality textures not limited to the mesh face resolution, we leverage a neural field $\\psi$ . $\\psi$ takes as input a barycentric coordinate $p$ on a mesh face, along with mean face feature $F_{v}$ of all incident quad faces:", + "bbox": [ + 76, + 257, + 470, + 319 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\psi \\left(p, b _ {1} F _ {v _ {1}} + b _ {2} F _ {v _ {2}} + b _ {3} F _ {v _ {3}}\\right) = c \\in \\mathbf {R} _ {[ - 1, 1 ]} ^ {3}, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 120, + 327, + 470, + 347 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathcal{A} = \\{v_1, v_2, v_3\\}$ is the triangle half of a quad face $\\{v_1, v_2, v_4, v_3\\}$ in which $p$ lies, $\\{b_1, b_2, b_3\\}$ are the barycentric coordinates of $p$ with respect to triangle $\\mathcal{A}$ , and $c$ is the final output color. We can then generate arbitrary-resolution textures by densely sampling $\\psi$ on each mesh face.", + "bbox": [ + 76, + 354, + 468, + 431 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To supervise the learning of this mesh-field texture manifold, we differentiably render our generated textures for an adversarial loss with photorealistic 2D images. To render the generated textures, we sample $\\psi$ at the locations corresponding to each pixel in the rendered view. In addition to implicit field $\\psi$ rendering, we also pass the output feature map $F_{c}$ into one convolutional layer and render it using PyTorch3D [37] differentiable renderer and supervise it similarly as a proxy loss. We then train the texture manifold in an end-to-end fashion using a non-saturating GAN loss with gradient penalty and path length regularization.", + "bbox": [ + 75, + 431, + 472, + 598 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "During training, we do not use any paired geometry with rendered images and only use unpaired collections of real-world images and synthetic shapes.", + "bbox": [ + 75, + 597, + 470, + 643 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Texture Transfer from a Single Image", + "text_level": 1, + "bbox": [ + 76, + 650, + 403, + 667 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Once learned, we can not only use our texture manifold for unconditional generation, but also importantly traverse through the manifold to produce shape texturing that matches to a query RGB image $I$ . This represents real-world texturing scenarios where a user may wish to texture a shape based on an easy-to-capture image inspiration. Here, notable challenges are lack of knowledge of the ground truth object pose in $I$ , and handling inexact geometric matches between the shape mesh to be textured and the object in $I$ – as it is not practical, nor always desirable, to assume the ability to reconstruct or retrieve the exact geometry of the object in an arbitrary image. We thus aim to produce textures on a shape to perceptually match an image $I$ in these challenging scenarios. Our texture transfer optimization is illustrated in Figure 4.", + "bbox": [ + 75, + 674, + 472, + 902 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/0cd58eb7be127c44c750ee16710cbda8e5757cf3a38a92b7c351d95d351b67b5.jpg", + "image_caption": [ + "Figure 3: Mesh-field texture generation. We employ face convolutions following [42] for initial coarse feature generation, followed by a neural field that interprets the per-face features to produce refined color outputs at arbitrary locations on the mesh surface. The hybrid mesh-field texture generation is supervised in an adversarial fashion through differentiable rendering, with photorealistic 2D images representing the real distribution." + ], + "image_footnote": [], + "bbox": [ + 506, + 89, + 890, + 202 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/cdb58652f794816070dfb59a6ac4423cd845e7b93cb106b671583cecbdcdcc21.jpg", + "image_caption": [ + "Figure 4: Texture transfer optimization from a single image. We traverse our learned texture manifold for texture transfer from a single RGB image query. Since image alignment may be unknown, we estimate a coarse pose along with finer-grained dense NOC correspondences. We leverage the NOCs to guide patch sampling for our patch-based style loss to produce texturing that perceptually matches to the query images, without requiring any exact geometric shape matches to the image." + ], + "image_footnote": [], + "bbox": [ + 509, + 364, + 883, + 484 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "From $I$ , we first estimate the object pose as the azimuth and elevation angles, $\\alpha^a$ and $\\alpha^e$ , respectively. To this end, we use a ResNet-18 [14] network on $I$ , pre-trained on synthetic rendered shapes to classify $\\alpha^a$ and $\\alpha^e$ into 12 and 5 bins for a coarse rotation estimate. For finer-grained reasoning, we predict normalized object coordinates [45] $I_{\\mathrm{NOC}}$ , dense correspondences from the object pixels in $I$ to the canonical space of the object. For NOC prediction, we use a UNet-style network with an EfficientNet-b4 [43] backbone, trained on synthetic rendered shape data.", + "bbox": [ + 496, + 672, + 893, + 824 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We then formulate our texture transfer optimization. We differentiably render our generated texture from initial pose estimate $\\alpha^a$ and $\\alpha^e$ to produce the rendered image produced from local neural field $\\psi X$ . Since we optimize for perceptual similarity, we employ a style loss [13] in a global and", + "bbox": [ + 496, + 825, + 893, + 902 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "8921", + "bbox": [ + 482, + 944, + 513, + 957 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "local fashion to compare $X$ and $I$ .", + "bbox": [ + 76, + 90, + 307, + 104 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We then optimize for latent texture code $z$ with the loss:", + "bbox": [ + 96, + 106, + 467, + 121 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} L = w _ {g l o b} \\sum_ {h = 1} ^ {N _ {h}} \\sum_ {l = 1} ^ {N _ {l}} L _ {g l o b} \\left(I ^ {h, l}, X ^ {h, l}\\right) \\\\ + w _ {p a t c h} \\sum_ {p = 1} ^ {N _ {p}} \\sum_ {h = 1} ^ {N _ {h}} \\sum_ {l = 1} ^ {N _ {l}} L _ {p a t c h} \\left(I _ {p} ^ {h, l} (x, y), X _ {p} ^ {h, l} \\left(x ^ {\\prime}, y ^ {\\prime}\\right)\\right), \\tag {2} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 76, + 128, + 468, + 232 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $L_{glob}$ denotes a global style loss, $L_{patch}$ a local patch-based style loss, and $w_{glob}$ and $w_{patch}$ constants to balance the loss values.", + "bbox": [ + 75, + 239, + 470, + 285 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Global style loss. $L_{glob}$ considers the full images $I$ and $X$ at $N_h = 3$ resolution levels (original, half, and quarter resolution): $I^h$ and $X^h$ , $h \\in [1,2,3]$ . The global style loss is then computed on each pair $(X^h, I^h)$ on $N_l = 5$ VGG feature layers.", + "bbox": [ + 75, + 303, + 468, + 378 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Patch style losses. Since the precise structure of the object in $I$ may not match with that of $X$ (e.g. geometry mismatch or inconsistent pose prediction), we further employ local style losses on image patches. We extract $N_{p} = 2$ patches $I_{p}(x,y)$ from $I$ randomly per iteration, located at patch centers $(x,y)$ within the object. We then use the corresponding NOC estimate at the patch location, $I_{\\mathrm{NOC}}(x,y)$ , and find a corresponding patch $X_{p}(x^{\\prime},y^{\\prime})$ where $(x^{\\prime},y^{\\prime})$ is the pixel location whose shape NOC is closest to $I_{\\mathrm{NOC}}(x,y)$ w.r.t. $\\ell_2$ distance. Note that since $X$ has been rendered from a shape mesh, we can use ground truth shape NOCs for $X$ , and only require predicted NOCs for $I$ . This provides a coarse correspondence between patches to guide the style loss. Similar to $L_{glob}$ , we apply $L_{patch}$ at $N_{h} = 3$ resolution levels and with $N_{l} = 5$ VGG feature layers.", + "bbox": [ + 75, + 397, + 470, + 623 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Face feature refinement. With texture code $z$ optimized from Equation 2, we further allow for texture refinement by unfreezing the last two face convolutional layers in the texture generator. We optimize for refined weights in the surface features using only $L_{patch}$ , which enables better capturing of local detail in $I$ .", + "bbox": [ + 75, + 641, + 468, + 732 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Implementation Details Our Mesh2Tex model is implemented using PyTorch and trained using an Adam [23] optimizer with learning rates of 1e-4, 12e-4, 1e-4, 14e-4 for the encoder, generator, neural field $\\psi$ parameters and both discriminators, respectively. Mesh2Tex is trained on 2 NVIDIA A6000s for 50k iterations ( $\\sim$ 100 hours) until convergence.", + "bbox": [ + 75, + 750, + 468, + 839 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "At test-time, we optimize latent codes for 100 iterations and refined weights for additional 300 iterations, which takes $\\sim 400$ s in total. During texture optimization, we extract $64 \\times 64$ patches. We provide further details in the supplemental.", + "bbox": [ + 75, + 839, + 467, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Results", + "text_level": 1, + "bbox": [ + 500, + 90, + 586, + 104 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We evaluate the texture generation capabilities of Mesh2Tex on unconditional generation and image-based texture generation, on both synthetic and real data. For both scenarios, our texture generation is trained from real images.", + "bbox": [ + 498, + 116, + 893, + 178 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Datasets. For evaluation, we use object geometry from ShapeNet [4] for texturing, and real-world query images from ScanNet [8] for chairs, and from CompCars [49] for cars. For synthetic experiments requiring exact geometric matches, we use ShapeNet textured objects and render query image views. For real image queries with close matching geometry, we use Scan2CAD [1] annotations for chair meshes to ScanNet images. For CompCars, we use the coarse pose information (front, back, left, right, etc.) to estimate close image alignments. During training, poses are rendered to coarsely approximate the distribution of real train images (e.g., for cars, 8 poses representing front, back, left, right, front-left, front-right, back-left, and back-right; for chairs, random poses from PhotoShape pose estimates).", + "bbox": [ + 496, + 205, + 893, + 417 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Note that all methods, except GET3D, were trained with the same set of ShapeNet meshes, and images from PhotoShape [34] and CompCars [49] for chairs and cars. GET3D requires a much denser sampling of images per shape rather than a single view per shape, so we instead compare with the authors' released pre-trained GET3D model.", + "bbox": [ + 496, + 419, + 893, + 510 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Evaluation metrics. We evaluate the perceptual quality of our generated textures with several metrics. To measure the realistic quality of the textures, we compare rendered views of generated textures on various shapes to real-world images, using the standard FID [16] and KID [2] scores used for assessing generated image quality. For FID and KID evaluation, we use real images from PhotoShape [34] and CompCars [49] for chairs and cars, respectively, and 6 rendered views from each synthesized textured shape. Additionally, for texture transfer from a single image, we compute CLIP [36] similarity as cosine distances between the query image and rendered texture. In synthetic experiment setups where exact geometric matches are available, we further compute an LPIPS [51] perceptual metric between synthesized views and the query image.", + "bbox": [ + 496, + 539, + 893, + 767 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Baselines. We compare with several state-of-the-art texturing methods leveraging various texture representations: Yu et. al. [50] learns texture generation on a UV map parameterization, EG3D [3] leverages an efficient triplane representation for view synthesis, Texturify [42] generates per-face colors on a mesh, and GET3D [11] jointly estimates color and geometry with triplane representations.", + "bbox": [ + 496, + 794, + 893, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "8922", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/d0013ebdc1f5400695e82c1fbd471b2120309b1ad95a9ff4add7b59ca0ca4734.jpg", + "image_caption": [ + "Figure 5: Unconditional texturing for meshes from ShapeNet [4], in comparison with state of the art. Our approach generates more realistic, detailed textures." + ], + "image_footnote": [], + "bbox": [ + 83, + 88, + 467, + 377 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/deb893a413c8a32d831fd5afc74de7c146d8e7e7d1d783ec716e42f2005a9c49.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodParameterizationChairsCars
FIDKIDFIDKID
EG3DTri-plane Implicit36.452.1583.115.95
Yu et al.UV38.982.4673.635.77
GET3DTri-plane Implicit46.203.0289.626.92
Texturify4-RoSy Field31.081.7559.554.97
Ours4-RoSy Implicit Field30.011.6941.353.41
", + "bbox": [ + 81, + 462, + 468, + 556 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 1: Unconditional texture generation for 3D shapes. Our mesh-field approach outperforms state of the art in generation quality. The KID values are scaled by $10^{2}$ .", + "bbox": [ + 75, + 566, + 470, + 613 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Unconditional Texture Generation", + "text_level": 1, + "bbox": [ + 76, + 641, + 377, + 657 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 1 and Figure 5 show quantitative and qualitative comparisons of unconditional texture generation to state of the art. Our hybrid mesh-field texture representation enables richer texture generation with finer-scale details than state-of-the-art baselines.", + "bbox": [ + 75, + 666, + 470, + 742 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Texture Transfer from a Single Image", + "text_level": 1, + "bbox": [ + 76, + 753, + 403, + 772 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We further evaluate texturing of objects from image queries, which opens up new possibilities in the content creation process. We consider both synthetic image queries, which enable texturing of exact geometric matches, as well as real image queries, where no object geometry matches exactly to the queries. For all baselines, we apply a similar texture optimization as our approach, leveraging global and patch-style losses without NOC guidance. During test-time", + "bbox": [ + 75, + 780, + 470, + 902 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/7ddc1782154188f13c5cfd1743876dc8807d6cb5722cfc53f469bc9e940a71a3.jpg", + "image_caption": [ + "Figure 6: Texture transfer from synthetic image queries to exact shape geometry with unknown image alignment. Mesh2Tex produces more geometrically consistent texturing with finer-resolution details captured in our mesh-field texture representation. Note that GET3D models both geometry and color, resulting in possible geometric changes." + ], + "image_footnote": [], + "bbox": [ + 506, + 89, + 888, + 412 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "optimization in texture transfer experiments, we consider settings of known/unknown shape and pose for image queries, but we use the same adversarially trained model for all test-time experiments.", + "bbox": [ + 496, + 551, + 893, + 613 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2.1 Synthetic Image Query Experiments", + "text_level": 1, + "bbox": [ + 500, + 631, + 808, + 647 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Exact geometry and known image alignment. We evaluate texture generation from a single image query to exactly matching object geometry with known image alignment in Tables 2 and 3, which measure the distribution quality and perceptual match to the query image, respectively. The optimization through our high-fidelity texture manifold enables more detailed texturing to match to various texture changes in the query image, in comparison to baselines.", + "bbox": [ + 496, + 655, + 893, + 777 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Exact geometry and unknown image alignment. We evaluate texture generation from a single image query where the pose of the shape in the input query is unknown. Quantitative evaluation with state of the art is shown in Tables 4 and 5, which measure the distribution quality and perceptual match to the query image, respectively. Figure 6 visualizes qualitative comparisons. For GET3D, we do not evaluate", + "bbox": [ + 496, + 795, + 893, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "8923", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/549825ed01b8ce553467c83e10f6b6ebca9bd4009b0a44d3ede2f320263d4303.jpg", + "image_caption": [ + "Figure 7: Texture transfer from real images (ScanNet) to closely matching shape geometry (ShapeNet). Despite inexact geometry and pose, Mesh2Tex produces perceptually consistent texturing." + ], + "image_footnote": [], + "bbox": [ + 96, + 89, + 450, + 428 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "LPIPS, as it can produce geometric changes resulting in an inexact geometry match to the query.", + "bbox": [ + 75, + 537, + 468, + 569 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Even with exact geometry, the unknown image alignment poses a notable challenge, resulting in degraded performance in the baselines. Our approach maintains more robustness due to the NOC guidance in our patch loss during texture optimization, producing more plausible texture generation.", + "bbox": [ + 75, + 569, + 468, + 645 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Texture transfer. We evaluate texture transfer experiments from a single image query to an arbitrary shape of a different geometry than the input query. Tables 6 and 7 compare our approach to state of the art. This challenging scenario of differing geometry results in a performance drop in all methods; however, due to our NOC-guided style optimization on a mesh-field texture representation, Mesh2Tex can produce textures on novel shape geometry with greater coherency and finer details than baselines.", + "bbox": [ + 75, + 662, + 468, + 797 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.2.2 Real Image Query Experiments", + "text_level": 1, + "bbox": [ + 76, + 816, + 352, + 832 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Closely-matching geometry and image alignment. We evaluate texturing from a single real-world image, where the shape geometry to be textured and image alignment are close (as we cannot guarantee an exact match to real-world", + "bbox": [ + 75, + 839, + 468, + 900 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/919d674751877b92c8c90b9692ffcf07a0ad547046ec1816834f0e632385e1ba.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
FIDKIDFIDKIDFIDKID
EG3D146.69.49297.920.82318.827.39
Yu et al.153.110.2289.418.88329.828.60
GET3D265.626.67248.815.57336.538.74
Texturify155.910.94301.420.63342.233.65
Ours115.45.38165.56.84309.726.50
", + "bbox": [ + 504, + 88, + 890, + 215 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 2: Evaluation on aligned queried texture generation with image queries from rendered ShapeNet chairs and cars, as well as real-world images from ScanNet chairs. Mesh2Tex generates more realistic textures from single-image queries. The KID values are scaled by $10^{2}$ .", + "bbox": [ + 496, + 226, + 893, + 303 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "images). We compare with state of the art in Tables 2 and 3. In the real-world setting, view-dependent effects in real images (e.g., specular highlights, reflections) pose a notable challenge in evaluating texture optimization. With close but inexact geometry and alignment, our method can still produce textures that are consistent with the image queries due to NOC-guided optimization, while baseline methods struggle to transfer textures from incomplete and cluttered real-world objects.", + "bbox": [ + 496, + 328, + 890, + 465 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Closely-matching geometry and unknown image alignment. We further consider texturing from a single real-world image to close shape geometry with unknown image alignment. We show qualitative results in Figure 7 and quantitative evaluation in Tables 4 and 5. Our NOC-guided optimization through our texture manifold generates more perceptually representative textures.", + "bbox": [ + 496, + 484, + 893, + 590 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Texture transfer. Finally, we evaluate the challenging texture transfer scenario from a single real-world image from ScanNet [8] to an arbitrary ShapeNet [4] mesh of the same class category. This reflects potential texturing applications from users who wish to use an inspirational image to generate texturing on a given shape. We show a quantitative comparison in Tables 6 and 7, and qualitative results in Figure 8. Our mesh-field texture representation maintains more detail with NOC-guided patch loss to provide more robustness during optimization.", + "bbox": [ + 496, + 609, + 893, + 760 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Generated textures may differ from input images in Figs. 7 and 8 since shape geometry and poses differ between the shape to be textured and the query image. Thus, we cannot leverage any 1-1 correspondences, instead optimizing for patch-based perceptual similarity.", + "bbox": [ + 496, + 761, + 890, + 837 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Applicability to real scans", + "text_level": 1, + "bbox": [ + 500, + 845, + 735, + 863 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Our method can also be easily applied to real scanned shapes, by applying QuadriFlow [18] to convert Marching", + "bbox": [ + 500, + 869, + 890, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "8924", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/92bdb086cc612d4c851b461e1dda894964d6d3659ac19a99f642b550f2f53807.jpg", + "image_caption": [ + "Figure 8: Texture transfer from real images (ScanNet, CompCars) to arbitrary shape geometry of the same class category (ShapeNet). Under this challenging scenario, our NOC-guided patch optimization enables plausible texturing for image queries." + ], + "image_footnote": [], + "bbox": [ + 80, + 88, + 468, + 406 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/4079c15c8602aea0b5d9034c78b98d4376cd101d065ee7bd017c98a40ebdb1d4.jpg", + "image_caption": [ + "Figure 9: Texturing on real scanned objects from Redwood dataset. Mesh2Tex is able to generate consistent textures for non-synthetic geometry without finetuning." + ], + "image_footnote": [], + "bbox": [ + 91, + 523, + 452, + 612 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Cubes meshes to a quad mesh input. Fig. 9 shows our texturing of scanned shapes from the Redwood [6] dataset based on real ScanNet image queries.", + "bbox": [ + 75, + 712, + 470, + 758 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.4. Ablations", + "text_level": 1, + "bbox": [ + 76, + 770, + 189, + 786 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "What is the impact of our mesh-field representation for texture generation? Texturify [42] represents a per-face mesh color generation approach and the texturing results in coarse alignment of geometry and color features, while we introduce a shared barycentric neural field to capture high-fidelity details. Figure 5 shows our much finer-level detail generation, particularly for complex textures on cars.", + "bbox": [ + 75, + 794, + 470, + 902 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/57a2707f49b66021e29bbca880447b75f69c2abd6d9d146726a6389a2f1d217c.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
CLIPLPIPSCLIPLPIPSCLIP
EG3D89.8716.4183.2715.6982.86
Yu et al.89.7316.2684.3314.8382.93
GET3D85.00-81.38-78.52
Texturify89.2216.2383.8214.6981.71
Ours92.2714.6485.9114.7784.28
", + "bbox": [ + 504, + 88, + 893, + 213 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 3: Evaluation on aligned queried texture generation with image queries from rendered ShapeNet chairs and cars, as well as real-world images from ScanNet chairs. Our texture transfer optimization produces more perceptually representative texturing results.", + "bbox": [ + 496, + 222, + 893, + 299 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "What is the impact of patch style loss in the texture optimization process? Table 8 shows that our patch-based style loss significantly improves texture transfer optimization performance, allowing for the capture of more local detail and robustness to mismatches to the query image. The patch-based optimization enables better capture of texture differences in shape parts than when only using the whole image. Namely, ablating patch style loss results in texture leaks between parts of different colors, an inability to capture textures of fine structures such as thin chair legs, and artifacts around texture-background borders.", + "bbox": [ + 496, + 327, + 893, + 493 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "What is the impact of NOC guidance for the patch style loss? In Table 8, we see that the NOC guidance helps to improve the perceptual quality of results by establishing coarse correspondence to the query image. The NOC guidance largely affects local texture changes inherent to small-scale and thin parts (e.g., chair arms, legs), while only global style is captured without NOCs.", + "bbox": [ + 496, + 494, + 893, + 599 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "What is the effect of surface feature optimization? Following latent texture code optimization, we allow for surface features in the texture generator to further be optimized, which produces slightly improved local texture detail, as shown in Table 8. Optimizing for surface features allows for non-harmful and small extending the flexibility of texture generation to better express high-contrast textures.", + "bbox": [ + 496, + 601, + 893, + 707 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "What is the effect of global style loss? Table 8 shows that without our global style loss, the consistency of texture transfer is severely reduced. The single patch-based style loss enhances similarity to queries locally, but not globally.", + "bbox": [ + 496, + 708, + 890, + 768 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Following latent texture code optimization, we allow for surface features in the texture generator to further be optimized, which produces slightly improved local texture detail, as shown in Table 8.", + "bbox": [ + 496, + 770, + 893, + 829 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We refer to the supplemental for qualitative ablation analysis.", + "bbox": [ + 500, + 830, + 893, + 847 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Limitations. Mesh2Tex offers a promising step towards conditional mesh texturing from a single image, though vari-", + "bbox": [ + 498, + 869, + 893, + 902 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "8925", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/8cb32d160a0199ec0e9bd4ec36cd4d14589313af81596b510e7ae84f362d7576.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
FIDKIDFIDKIDFIDKID
EG3D155.29.13326.824.48319.427.18
Yu et al.160.09.88343.332.71327.128.20
GET3D271.926.54254.416.63337.338.76
Texturify174.211.74344.225.34333.328.81
Ours121.15.08165.86.77311.926.73
", + "bbox": [ + 81, + 88, + 467, + 215 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/9e024271612caed987465241e9a4fcddfa5cf20c0bfc62920729864d19244d4b.jpg", + "table_caption": [ + "Table 4: Evaluation on unaligned queried texture generation with image queries from rendered ShapeNet chairs and cars, as well as real images from ScanNet chairs. Mesh2Tex maintains more realistic texture details than state of the art. The KID values are scaled by $10^{2}$ ." + ], + "table_footnote": [], + "table_body": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
CLIPLPIPSCLIPLPIPSCLIP
EG3D89.5116.8381.9316.1483.40
Yu et al.88.9816.8179.3521.8482.67
GET3D84.66-81.54-79.02
Texturify88.2416.8280.4515.4282.26
Ours91.5714.9685.4214.9784.28
", + "bbox": [ + 81, + 332, + 467, + 454 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/b10bc9aa0aad8f420ab8757700e813acae49c7f4564ad3b3dd63c8991d8d271c.jpg", + "table_caption": [ + "Table 5: Evaluation on unaligned queried texture generation to ShapeNet chairs and cars from rendered ShapeNet objects as well as real-world image queries from ScanNet chairs. Our NOC-guided patch style loss maintains more robustness to the unknown image alignment." + ], + "table_footnote": [], + "table_body": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNetCars CompCars
FIDKIDFIDKIDFIDKIDFIDKID
EG3D297.428.53343.626.57355.233.31352.339.15
Yu et al.303.429.10351.126.75362.634.20385.451.37
GET3D--------
Texturify307.929.63357.127.05370.434.85264.729.23
Ours276.726.17194.510.11348.532.33203.721.48
", + "bbox": [ + 81, + 571, + 467, + 664 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "ous limitations remain. For instance, our approach does not explicitly model semantics, potentially leading to distortions in texture in semantically meaningful areas (e.g., spokes of a car wheel). Additionally, a more explicit characterization of the texture distribution could enable probabilistic sampling when input queries may be occluded or incomplete.", + "bbox": [ + 75, + 809, + 470, + 902 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/c0bd8db6badfe34d4dcd91a0ea3e1d1d2b7ca22836d28cbd718b8bf6f4897219.jpg", + "table_caption": [ + "Table 6: Evaluation on texture transfer to ShapeNet chairs and cars from rendered ShapeNet objects as well as real-world image queries from ScanNet chairs and CompCars cars. In this challenging scenario, our mesh-field representation retains more realistic detail in texture optimization. The KID values are scaled by $10^{2}$ ." + ], + "table_footnote": [], + "table_body": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNetCars CompCars
CLIPCLIPCLIPCLIP
EG3D81.6280.7281.5468.18
Yu et al.81.3178.6981.2164.76
GET3D----
Texturify80.7078.5980.9966.93
Ours83.4782.2081.9577.71
", + "bbox": [ + 504, + 88, + 890, + 205 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/20c2a5d203b5b59e215dc0191e222b05026b85fe50a75f625de576771faae549.jpg", + "table_caption": [ + "Table 7: Evaluation on texture transfer to ShapeNet chairs and cars from rendered ShapeNet objects as well as real-world image queries from ScanNet chairs and CompCars cars. Our NOC-guided patch style loss enables better characterization of the input query image for texturing." + ], + "table_footnote": [], + "table_body": "
MethodChairs (unaligned) ShapeNet
FIDKIDCLIP
w/o NOC124.35.5391.09
w/o patches143.56.9189.68
w/o surf. features127.15.8090.70
w/o glob. style169.610.1288.05
Ours121.15.0891.57
", + "bbox": [ + 547, + 309, + 844, + 431 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 8: Ablation study on texture transfer optimization design. Our NOC guidance, patch style loss, and surface feature optimization help to improve generated texture quality. The KID values are scaled by $10^{2}$ .", + "bbox": [ + 496, + 441, + 893, + 503 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 532, + 617, + 549 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We presented Mesh2Tex, which learns a texture manifold based on a hybrid mesh-field representation to generate realistic, high-quality textures on shape geometry from real-world imagery. Mesh2Tex enables test-time optimization for texture transfer from single image queries. Crucially, our NOC-guided local and global style loss enables optimization for perceptually matching textures on a 3D shape that does not require exact geometric matches to RGB image queries. We believe this opens up many new possibilities in texturing for content creation, enabling easy-to-capture images to be used as guidance for holistic shape texturing.", + "bbox": [ + 496, + 559, + 893, + 727 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgements. This work was supported by the Bavarian State Ministry of Science and the Arts coordinated by the Bavarian Research Institute for Digital Transformation (bidt). ST was partially supported by a gift award from CISCO.", + "bbox": [ + 496, + 738, + 893, + 800 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 500, + 816, + 596, + 834 + ], + "page_idx": 8 + }, + { + "type": "ref_text", + "text": "[1] Armen Avetisyan, Manuel Dahnert, Angela Dai, Manolis Savva, Angel X. Chang, and Matthias Nießner. Scan2cad: Learning CAD model alignment in RGB-D scans. In IEEE Conference on Computer Vision and Pattern Recognition,", + "bbox": [ + 506, + 844, + 893, + 902 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "8926", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 2614-2623, 2019. 5", + "[2] Mikołaj Binkowski, Danica J Sutherland, Michael Arbel, and Arthur Gretton. Demystifying mmd gans. arXiv preprint arXiv:1801.01401, 2018. 5", + "[3] Eric R. Chan, Connor Z. Lin, Matthew A. Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas Guibas, Jonathan Tremblay, Sameh Khamis, Tero Karras, and Gordon Wetzstein. Efficient geometry-aware 3D generative adversarial networks. In arXiv, 2021. 2, 3, 5", + "[4] Angel X Chang, Thomas Funkhouser, Leonidas Guibas, Pat Hanrahan, Qixing Huang, Zimo Li, Silvio Savarese, Manolis Savva, Shuran Song, Hao Su, et al. Shapenet: An information-rich 3d model repository. arXiv preprint arXiv:1512.03012, 2015. 5, 6, 7", + "[5] Zhiqin Chen and Hao Zhang. Learning implicit fields for generative shape modeling. Proceedings of IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2019. 2", + "[6] Sungjoon Choi, Qian-Yi Zhou, and Vladlen Koltun. Robust reconstruction of indoor scenes. In 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 5556-5565, 2015. 8", + "[7] Manuel Dahnert, Ji Hou, Matthias Nießner, and Angela Dai. Panoptic 3d scene reconstruction from a single rgb image. In Thirty-Fifth Conference on Neural Information Processing Systems, 2021. 2", + "[8] Angela Dai, Angel X. Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Niessner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In The IEEE Conference on Computer Vision and Pattern Recognition (CVPR), July 2017. 5, 7", + "[9] Angela Dai, Yawar Siddiqui, Justus Thies, Julien Valentin, and Matthias Nießner. Spsg: Self-supervised photometric scene generation from rgb-d scans. In Proc. Computer Vision and Pattern Recognition (CVPR), IEEE, 2021. 2", + "[10] Yu Deng, Jiaolong Yang, and Xin Tong. Deformed implicit field: Modeling 3d shapes with learned dense correspondence. In IEEE Computer Vision and Pattern Recognition, 2021. 2", + "[11] Jun Gao, Tianchang Shen, Zian Wang, Wenzheng Chen, Kangxue Yin, Daiqing Li, Or Litany, Zan Gojcic, and Sanja Fidler. Get3d: A generative model of high quality 3d textured shapes learned from images. In Advances In Neural Information Processing Systems, 2022. 3, 5", + "[12] Lin Gao, Tong Wu, Yu-Jie Yuan, Ming-Xian Lin, Yu-Kun Lai, and Hao Zhang. Tm-net: Deep generative networks for textured meshes. 10 2020. 2", + "[13] Leon A Gatys, Alexander S Ecker, and Matthias Bethge. Image style transfer using convolutional neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2414-2423, 2016. 4", + "[14] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 4", + "[15] Paul Henderson, Vagia Tsiminaki, and Christoph H Lampert. Leveraging 2d data to learn textured 3d mesh generation." + ], + "bbox": [ + 78, + 90, + 470, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7498-7507, 2020. 2", + "[16] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in neural information processing systems, 30, 2017. 5", + "[17] Jingwei Huang, Justus Thies, Angela Dai, Abhijit Kundu, Chiyu Jiang, Leonidas J Guibas, Matthias Niessner, and Thomas Funkhouser. Adversarial texture optimization from rgb-d scans. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1559-1568, 2020. 2", + "[18] Jingwei Huang, Yichao Zhou, Matthias Niessner, Jonathan Richard Shewchuk, and Leonidas J Guibas. Quadriflow: A scalable and robust method for quadrangulation. In Computer Graphics Forum, volume 37, pages 147-160. Wiley Online Library, 2018. 4, 7", + "[19] Ajay Jain, Ben Mildenhall, Jonathan T. Barron, Pieter Abbeel, and Ben Poole. Zero-shot text-guided object generation with dream fields. CVPR, 2022. 3", + "[20] Krishna Murthy Jatavallabhula, Alihusein Kuwajerwala, Qiao Gu, Mohd Omama, Tao Chen, Shuang Li, Ganesh Iyer, Soroush Saryazdi, Nikhil Keetha, Ayush Tewari, et al. Conceptfusion: Open-set multimodal 3d mapping. arXiv preprint arXiv:2302.07241, 2023. 3", + "[21] Xie Jianwen, Yifei Xu, Zilong Zheng, Song Zhu, and Ying-nian Wu. Generative pointnet: Energy-based learning on unordered point sets for 3d generation, reconstruction and classification. 04 2020. 2", + "[22] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of stylegan. CVPR, 2020. 4", + "[23] Diederik P. Kingma and Jimmy Ba. Adam: A method for stochastic optimization. CoRR, abs/1412.6980, 2014. 5", + "[24] Juil Koo, Ian Huang, Panos Achlioptas, Leonidas J Guibas, and Minhyuk Sung. Partglot: Learning shape part segmentation from language reference games. In Proceedings of IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 3", + "[25] Weicheng Kuo, Anelia Angelova, Tsung-Yi Lin, and Angela Dai. Patch2cad: Patchwise embedding learning for in-the-wild shape retrieval from a single image. 2021 IEEE/CVF International Conference on Computer Vision (ICCV), pages 12569-12579, 2021. 2", + "[26] Shitong Luo and Wei Hu. Diffusion probabilistic models for 3d point cloud generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), June 2021. 2", + "[27] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3d reconstruction in function space. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 4460-4470, 2019. 2", + "[28] Oscar Michel, Roi Bar-On, Richard Liu, Sagie Benaim, and Rana Hanocka. Text2mesh: Text-driven neural stylization for meshes. arXiv preprint arXiv:2112.03221, 2021. 3" + ], + "bbox": [ + 503, + 92, + 893, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "8927", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[29] Paritosh Mittal, Yen-Chi Cheng, Maneesh Singh, and Shubham Tulsiani. AutoSDF: Shape priors for 3d completion, reconstruction and generation. In CVPR, 2022. 2", + "[30] Charlie Nash, Yaroslav Ganin, S. Eslami, and Peter Battaglia. *Polygon: An autoregressive generative model of 3d meshes.* 02 2020. 2", + "[31] Michael Oechsle, Lars Mescheder, Michael Niemeyer, Thilo Strauss, and Andreas Geiger. Texture fields: Learning texture representations in function space. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4531-4540, 2019. 2", + "[32] Michael Oechsle, Lars Mescheder, Michael Niemeyer, Thilo Strauss, and Andreas Geiger. Texture fields: Learning texture representations in function space. In Proceedings IEEE International Conf. on Computer Vision (ICCV), 2019. 3", + "[33] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. Deepsdf: Learning continuous signed distance functions for shape representation. In 2019 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 165-174, 2019. 2", + "[34] Keunhong Park, Konstantinos Rematas, Ali Farhadi, and Steven M. Seitz. Photoshape: Photorealistic materials for large-scale shape collections. ACM Trans. Graph., 37(6), Nov. 2018. 2, 5", + "[35] Dario Pavllo, Jonas Kohler, Thomas Hofmann, and Aurelien Lucchi. Learning generative models of textured 3d meshes from real-world images. In IEEE/CVF International Conference on Computer Vision (ICCV), 2021. 2", + "[36] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International conference on machine learning, pages 8748-8763. PMLR, 2021. 3, 5", + "[37] Nikhila Ravi, Jeremy Reizenstein, David Novotny, Taylor Gordon, Wan-Yen Lo, Justin Johnson, and Georgia Gkioxari. Accelerating 3d deep learning with pytorch3d. arXiv:2007.08501, 2020.4", + "[38] David Rozenberszki, Or Litany, and Angela Dai. Language-grounded indoor 3d semantic segmentation in the wild. In Proceedings of the European Conference on Computer Vision (ECCV), 2022. 3", + "[39] Shunsuke Saito, Zeng Huang, Ryota Natsume, Shigeo Morishima, Angjoo Kanazawa, and Hao Li. Pifu: Pixel-aligned implicit function for high-resolution clothed human digitization. In The IEEE International Conference on Computer Vision (ICCV), October 2019. 2", + "[40] Shunsuke Saito, Tomas Simon, Jason Saragih, and Hanbyul Joo. Pifuhd: Multi-level pixel-aligned implicit function for high-resolution 3d human digitization. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, June 2020. 2", + "[41] Aditya Sanghi, Hang Chu, Joseph G Lambourne, Ye Wang, Chin-Yi Cheng, and Marco Fumero. Clip-forge: Towards zero-shot text-to-shape generation. arXiv preprint arXiv:2110.02624, 2021. 3" + ], + "bbox": [ + 78, + 90, + 470, + 898 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[42] Yawar Siddiqui, Justus Thies, Fangchang Ma, Qi Shan, Matthias Nießner, and Angela Dai. Texturify: Generating textures on 3d shape surfaces, 2022. 2, 4, 5, 8", + "[43] Mingxing Tan and Quoc V. Le. Efficientnet: Rethinking model scaling for convolutional neural networks. In ICML, 2019. 4", + "[44] Can Wang, Menglei Chai, Mingming He, Dongdong Chen, and Jing Liao. Clip-nerf: Text-and-image driven manipulation of neural radiance fields. ArXiv, abs/2112.05139, 2021. 3", + "[45] He Wang, Srinath Sridhar, Jingwei Huang, Julien Valentin, Shuran Song, and Leonidas J Guibas. Normalized object coordinate space for category-level 6d object pose and size estimation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2642-2651, 2019. 3, 4", + "[46] Qiangeng Xu, Weiyue Wang, Duygu Ceylan, Radomir Mech, and Ulrich Neumann. Disn: Deep implicit surface network for high-quality single-view 3d reconstruction. In H. Wallach, H. Larochelle, A. Beygelzimer, F. d'Alché-Buc, E. Fox, and R. Garnett, editors, Advances in Neural Information Processing Systems 32, pages 492-502. Curran Associates, Inc., 2019. 2", + "[47] Qiangeng Xu, Zexiang Xu, Julien Philip, Sai Bi, Zhixin Shu, Kalyan Sunkavalli, and Ulrich Neumann. Point-nerf: Point-based neural radiance fields. 2022 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 5428–5438, 2022. 2", + "[48] Bangbang Yang, Chong Bao, Junyi Zeng, Hujun Bao, Yinda Zhang, Zhaopeng Cui, and Guofeng Zhang. Neumesh: Learning disentangled neural mesh-based implicit field for geometry and texture editing. 07 2022. 2", + "[49] Linjie Yang, Ping Luo, Chen Change Loy, and Xiaou Tang. A large-scale car dataset for fine-grained categorization and verification. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3973-3981, 2015. 5", + "[50] Rui Yu, Yue Dong, Pieter Peers, and Xin Tong. Learning texture generators for 3d shape collections from internet photo sets. In *British Machine Vision Conference*, 2021. 5", + "[51] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In CVPR, 2018. 5", + "[52] Qian-Yi Zhou and Vladlen Koltun. Color map optimization for 3d reconstruction with consumer depth cameras. ACM Transactions on Graphics, 33, 08 2014. 2" + ], + "bbox": [ + 501, + 90, + 892, + 713 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "8928", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/743afd5f-14b2-4965-bbeb-bded0a673761_model.json b/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/743afd5f-14b2-4965-bbeb-bded0a673761_model.json new file mode 100644 index 0000000000000000000000000000000000000000..8391d7c404b2ae1f9cf08d32e2d203a1be2e5d1c --- /dev/null +++ b/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/743afd5f-14b2-4965-bbeb-bded0a673761_model.json @@ -0,0 +1,2235 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.188, + 0.131, + 0.784, + 0.154 + ], + "angle": 0, + "content": "Mesh2Tex: Generating Mesh Textures from Image Queries" + }, + { + "type": "text", + "bbox": [ + 0.218, + 0.182, + 0.472, + 0.216 + ], + "angle": 0, + "content": "Alexey Bokhovkin \nTechnical University of Munich" + }, + { + "type": "text", + "bbox": [ + 0.238, + 0.22, + 0.453, + 0.233 + ], + "angle": 0, + "content": "aleksei.bokhovkin@tum.de" + }, + { + "type": "text", + "bbox": [ + 0.529, + 0.182, + 0.751, + 0.217 + ], + "angle": 0, + "content": "Shubham Tulsiani \nCarnegie Mellon University" + }, + { + "type": "text", + "bbox": [ + 0.564, + 0.22, + 0.717, + 0.233 + ], + "angle": 0, + "content": "shubhtuls@cmu.edu" + }, + { + "type": "text", + "bbox": [ + 0.358, + 0.243, + 0.612, + 0.277 + ], + "angle": 0, + "content": "Angela Dai \nTechnical University of Munich" + }, + { + "type": "text", + "bbox": [ + 0.409, + 0.281, + 0.562, + 0.294 + ], + "angle": 0, + "content": "angela.dai@tum.de" + }, + { + "type": "image", + "bbox": [ + 0.116, + 0.303, + 0.283, + 0.612 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.302, + 0.303, + 0.568, + 0.613 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.587, + 0.302, + 0.853, + 0.613 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.075, + 0.617, + 0.895, + 0.679 + ], + "angle": 0, + "content": "Figure 1: Mesh2Tex learns realistic object texturing on a shape geometry through a hybrid mesh-field texture representation supporting high-resolution texture generation on various shape meshes. Furthermore, our learned texture manifold supports texture transfer optimization from image queries without requiring any matching geometry or pose alignment to the image, producing perceptually consistent texturing in this challenging content creation scenario." + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.687, + 0.314, + 0.703 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.72, + 0.474, + 0.903 + ], + "angle": 0, + "content": "Remarkable advances have been achieved recently in learning neural representations that characterize object geometry, while generating textured objects suitable for downstream applications and 3D rendering remains at an early stage. In particular, reconstructing textured geometry from images of real objects is a significant challenge – reconstructed geometry is often inexact, making realistic texturing a significant challenge. We present Mesh2Tex, which learns a realistic object texture manifold from uncorrelated collections of 3D object geometry and photorealistic RGB images, by leveraging a hybrid mesh-neural-field texture representation. Our texture representation enables compact encoding" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.689, + 0.895, + 0.854 + ], + "angle": 0, + "content": "of high-resolution textures as a neural field in the barycentric coordinate system of the mesh faces. The learned texture manifold enables effective navigation to generate an object texture for a given 3D object geometry that matches to an input RGB image, which maintains robustness even under challenging real-world scenarios where the mesh geometry approximates an inexact match to the underlying geometry in the RGB image. Mesh2Tex can effectively generate realistic object textures for an object mesh to match real images observations towards digitization of real environments, significantly improving over previous state of the art." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.855, + 0.895, + 0.885 + ], + "angle": 0, + "content": "Project page: alexeybokhovkin.github.io/ mesh2tex/" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8918" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.079, + 0.091, + 0.208, + 0.105 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.116, + 0.47, + 0.281 + ], + "angle": 0, + "content": "The ability to obtain 3D representations of real-world objects lies at the core of many important applications in graphics, robotics, movies and video games, and mixed reality. Approaches tackling the tasks of 3D generation [33, 26, 21, 29, 30, 10] or single-view reconstruction [5, 27, 46, 25, 7] enable users to easily create digital 3D assets, either from scratch or conditioned on an image. However, these approaches primarily focus on generating/inferring the geometry of objects, and this alone is insufficient to capture realistic environments, which requires high-quality texturing." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.282, + 0.471, + 0.493 + ], + "angle": 0, + "content": "In this work, we propose Mesh2Tex tackle the complementary task of high-fidelity texture generation given known object geometry. In addition to allowing texturing generation for a given object mesh, Mesh2Tex also enables image-based texture synthesis – synthesizing textures that perceptually match a single RGB image observation. In contrast to existing appearance modeling works that characterize texture as a field over the volume of 3D space [3, 39, 40, 31], we observe that object textures lie on object surfaces, and instead generate textures only on the mesh surface, with a hybrid explicit-implicit texture representation that ties the texture field to the barycentric coordinates of the mesh faces. This produces textured meshes directly compatible with downstream applications and 3D rendering engines." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.494, + 0.471, + 0.689 + ], + "angle": 0, + "content": "As large quantities of high-quality textured 3D objects are very expensive to obtain, requiring countless hours of skilled artists' work, we train our texture generator with uncorrelated collections of 3D object geometry and photorealistic 2D images, leveraging differentiable rendering to optimize mesh textures at arbitrary resolutions to match the quality of real 2D images in an adversarial fashion. That is, we generate coarse features and colors for each mesh face, which are then refined to high-resolution textures through a neural field defined on the barycentric coordinates of each mesh face. This hybrid texture representation enables differentiable rendering for texturing on explicit mesh surfaces while exploiting the efficiency of neural field representations." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.689, + 0.471, + 0.901 + ], + "angle": 0, + "content": "Our learned texture generator can then be used to produce realistic textures to match an input RGB observation of an object, by optimizing over our learned texture manifold conditioned on the mesh geometry, to find a latent texturing that perceptually matches the RGB image. As state-of-the-art object geometry reconstructions are typically inexact (e.g., noise, oversmoothing, retrieval from a database), our learned texture manifold enables effective regularization over plausible textures which effectively capture the perceptual input while providing realistic texturing over the full object. We formulate a patch-based style loss to capture perceptual similarities between our optimized texture and the RGB image, guided by dense correspondence prediction to correlate them. Experiments demonstrate that we outperform state of the art" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.894, + 0.121 + ], + "angle": 0, + "content": "in both unconditional texture generation as well as image-conditioned texture generation." + }, + { + "type": "text", + "bbox": [ + 0.52, + 0.123, + 0.75, + 0.137 + ], + "angle": 0, + "content": "In summary, our contributions are:" + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.149, + 0.894, + 0.254 + ], + "angle": 0, + "content": "- a new hybrid mesh-neural-field texture representation that enables diverse, realistic texture generation on object mesh geometry by tying a neural texture field to the barycentric coordinate system of the mesh faces. This enables learning a rich texture manifold from collections of uncorrelated real images and object meshes through adversarial differentiable rendering." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.266, + 0.894, + 0.356 + ], + "angle": 0, + "content": "- our learned texture manifold enables effective inference-time optimization to texture an object mesh to perceptually match a single real-world RGB image; crucially, we maintain robustness to real-world scenarios of differing views and even geometry with a patch-based perceptual optimization guided by dense correspondences." + }, + { + "type": "list", + "bbox": [ + 0.519, + 0.149, + 0.894, + 0.356 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.372, + 0.642, + 0.387 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.397, + 0.895, + 0.67 + ], + "angle": 0, + "content": "Optimization-based Texturing. Various approaches have been proposed to texture 3D shapes by optimizing from aligned image views of the shape. The traditional optimization approach of Zhou et. al. [52] solves a global optimization for a mapping from observed RGB images onto reconstructed geometry. More recently, Huang et. al. [17] introduce a modern adversarial discriminator loss, coupled with differentiable rendering, to optimize for texture on reconstructed geometry to produce realistic texturing robust to camera pose misalignments in real-world RGB-D capture scenarios. PointNeRF [47] and NeuMesh [48] optimize for view-dependent features using distance-based interpolation from the k-nearest neighbor points/vertices; in contrast, we aim to design a method with view-independent texturing that enables robustness to entirely arbitrary viewpoints. While these methods can produce impressive texturing results, they require aligned 2D/3D data and cannot produce textures in unobserved regions." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.69, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Learned Texture Completion and Generation. Learning-based methods have also explored generative texturing, aiming to learn generalized features for unconditional synthesis or conditional inpainting. Photoshop [34] proposes to learn material retrieval to apply materials to 3D shapes. Recently, several methods have been developed to generate textures on various representations: SPSG [9] produces per-voxel colors with an adversarial differentiable rendering formulation, Pavollo et. al. [35] learn texturing in the UV domain, and Henderson et. al. [15] and Texturify [42] propose to generate per-face mesh colors with variational and adversarial training, respectively. TM-NET [12] is basically the 2D approach for texture generation as it uses unfolded UV maps as the main representation, which is unable to generate" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8919" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.09, + 0.59, + 0.251 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.593, + 0.091, + 0.888, + 0.25 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.261, + 0.895, + 0.34 + ], + "angle": 0, + "content": "Figure 2: Method overview. Left: we first learn a texture generator for textures represented as a shared local neural field in the barycentric coordinate system of each mesh face. This enables the capture of high-resolution texture detail, while remaining tied to surface geometry, avoiding ambiguities of volumetric field representations. Our learned texture manifold can then be used for texture transfer from a single RGB query image, based on a correspondence-guided patch-based style loss to produce perceptually consistent texturing even for shapes with differing geometry and unknown image pose." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.377, + 0.473, + 0.499 + ], + "angle": 0, + "content": "consistent textures near the seams. Moreover, this method uses explicit part information, which significantly simplifies the setup for geometry-aware texture generation. The recent success of neural implicit field representations has also inspired implicit texture field models [32, 3, 11]. Our approach aims to model texture on the surface of a mesh, coupled with the representation capacity of a shared implicit field per mesh face." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.519, + 0.473, + 0.746 + ], + "angle": 0, + "content": "Query-based 3D Understanding. The recent success of vision-language models such as CLIP [36] has sparked interest in query-guided 3D understanding from text and images. Text and image guidance have been exploited for knowledge distillation for 3D semantic understanding [24, 38, 20]. Various shape generation tasks have also been formulated with text queries, by leveraging CLIP as supervision [41, 19, 44]. In particular, Text2Mesh [28] leverages CLIP guidance for text-based texture optimization on 3D shapes. We formulate Mesh2Tex to support image-based queries for texture transfer optimization to various 3D shapes, to reflect potential practical texturing scenarios where images are largely easy to capture or find, with high visual specificity. We thus tackle challenges in geometric and pose misalignments from various potential image queries." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.761, + 0.17, + 0.777 + ], + "angle": 0, + "content": "3. Method" + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.786, + 0.188, + 0.801 + ], + "angle": 0, + "content": "3.1. Overview" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.473, + 0.902 + ], + "angle": 0, + "content": "We aim to learn a high-quality texture manifold conditioned on a given shape mesh geometry, which supports unconditional texture generation as well as optimization within the texture manifold to fit to image queries for practical texturing scenarios. An overview of our approach is visualized in Figure 2. We propose to learn this texture manifold on a" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.377, + 0.895, + 0.528 + ], + "angle": 0, + "content": "hybrid representation that combines a mesh representation with a neural field operating on the barycentric coordinates of each mesh face. Our texture generator then generates initial coarse features per-face for a given shape mesh, which are then refined by a shared neural field across the mesh faces. This enables high-resolution texture generation by sampling the neural field on the mesh surface. In the absence of a large-scale dataset of high-quality 3D textured shapes, we supervise the texture generation with an adversarial loss with photorealistic 2D images, through differentiable rendering." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.529, + 0.896, + 0.697 + ], + "angle": 0, + "content": "We can then traverse our learned texture manifold to generate textures for a given shape geometry to perceptually match to image queries. Since an RGB image query may be taken at an arbitrary camera pose, we estimate the object pose in the RGB image along with its normalized object coordinates [45] to guide the texture optimization. Furthermore, we must also support texture transfer scenarios, as having an exact geometric shape match for an arbitrary RGB image query cannot be assumed in practice. We thus employ both a global and local patch-based style loss to generate a realistic texture that perceptually matches the query image." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.709, + 0.78, + 0.724 + ], + "angle": 0, + "content": "3.2. Mesh-Field Texture Generation" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.733, + 0.895, + 0.869 + ], + "angle": 0, + "content": "We learn a texture manifold on a mesh-field representation. Given a shape mesh \\(\\mathcal{M}\\), we use a latent-variable conditioned encoder-decoder to obtain per-face features \\(F\\). We then employ a shared neural field \\(\\psi\\) that operates on each face to produce arbitrary-resolution texturing. High-quality texture generation is then learned by supervision with photorealistic 2D images in an adversarial fashion through differentiable rendering. Our texture generator training is shown in Figure 3." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.895, + 0.902 + ], + "angle": 0, + "content": "A shape mesh \\(\\mathcal{M}\\) is represented as a quadrilateral mesh; inspired by the hierarchical mesh representation of Textu" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8920" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.258 + ], + "angle": 0, + "content": "rify [42], we also employ QuadriFlow [18] to parameterize shape meshes as hierarchies of 4-way rotationally symmetric (4-RoSy) fields. We can then leverage convolutional and pooling operators on the neighborhoods of each quad face, enabling encoding and decoding features on such mesh faces with arbitrary topologies. We employ an encoder-decoder face convolutional network \\( G \\) on \\( \\mathcal{M} \\), which takes as input geometric quad face features (per-face normals, fundamental forms, and curvature), and predicts per-face features \\( F_{c} \\). Similar to StyleGAN [22] we incorporate a latent texture code \\( z \\) into the decoder through a mapping network." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.258, + 0.472, + 0.32 + ], + "angle": 0, + "content": "As we aim to generate high-quality textures not limited to the mesh face resolution, we leverage a neural field \\(\\psi\\). \\(\\psi\\) takes as input a barycentric coordinate \\(p\\) on a mesh face, along with mean face feature \\(F_{v}\\) of all incident quad faces:" + }, + { + "type": "equation", + "bbox": [ + 0.122, + 0.328, + 0.471, + 0.348 + ], + "angle": 0, + "content": "\\[\n\\psi \\left(p, b _ {1} F _ {v _ {1}} + b _ {2} F _ {v _ {2}} + b _ {3} F _ {v _ {3}}\\right) = c \\in \\mathbf {R} _ {[ - 1, 1 ]} ^ {3}, \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.356, + 0.47, + 0.432 + ], + "angle": 0, + "content": "where \\(\\mathcal{A} = \\{v_1, v_2, v_3\\}\\) is the triangle half of a quad face \\(\\{v_1, v_2, v_4, v_3\\}\\) in which \\(p\\) lies, \\(\\{b_1, b_2, b_3\\}\\) are the barycentric coordinates of \\(p\\) with respect to triangle \\(\\mathcal{A}\\), and \\(c\\) is the final output color. We can then generate arbitrary-resolution textures by densely sampling \\(\\psi\\) on each mesh face." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.432, + 0.473, + 0.599 + ], + "angle": 0, + "content": "To supervise the learning of this mesh-field texture manifold, we differentiably render our generated textures for an adversarial loss with photorealistic 2D images. To render the generated textures, we sample \\(\\psi\\) at the locations corresponding to each pixel in the rendered view. In addition to implicit field \\(\\psi\\) rendering, we also pass the output feature map \\(F_{c}\\) into one convolutional layer and render it using PyTorch3D [37] differentiable renderer and supervise it similarly as a proxy loss. We then train the texture manifold in an end-to-end fashion using a non-saturating GAN loss with gradient penalty and path length regularization." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.598, + 0.472, + 0.644 + ], + "angle": 0, + "content": "During training, we do not use any paired geometry with rendered images and only use unpaired collections of real-world images and synthetic shapes." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.651, + 0.405, + 0.668 + ], + "angle": 0, + "content": "3.3. Texture Transfer from a Single Image" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.675, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Once learned, we can not only use our texture manifold for unconditional generation, but also importantly traverse through the manifold to produce shape texturing that matches to a query RGB image \\( I \\). This represents real-world texturing scenarios where a user may wish to texture a shape based on an easy-to-capture image inspiration. Here, notable challenges are lack of knowledge of the ground truth object pose in \\( I \\), and handling inexact geometric matches between the shape mesh to be textured and the object in \\( I \\) – as it is not practical, nor always desirable, to assume the ability to reconstruct or retrieve the exact geometry of the object in an arbitrary image. We thus aim to produce textures on a shape to perceptually match an image \\( I \\) in these challenging scenarios. Our texture transfer optimization is illustrated in Figure 4." + }, + { + "type": "image", + "bbox": [ + 0.507, + 0.09, + 0.891, + 0.203 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.215, + 0.895, + 0.336 + ], + "angle": 0, + "content": "Figure 3: Mesh-field texture generation. We employ face convolutions following [42] for initial coarse feature generation, followed by a neural field that interprets the per-face features to produce refined color outputs at arbitrary locations on the mesh surface. The hybrid mesh-field texture generation is supervised in an adversarial fashion through differentiable rendering, with photorealistic 2D images representing the real distribution." + }, + { + "type": "image", + "bbox": [ + 0.51, + 0.366, + 0.885, + 0.485 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.496, + 0.895, + 0.633 + ], + "angle": 0, + "content": "Figure 4: Texture transfer optimization from a single image. We traverse our learned texture manifold for texture transfer from a single RGB image query. Since image alignment may be unknown, we estimate a coarse pose along with finer-grained dense NOC correspondences. We leverage the NOCs to guide patch sampling for our patch-based style loss to produce texturing that perceptually matches to the query images, without requiring any exact geometric shape matches to the image." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.674, + 0.895, + 0.825 + ], + "angle": 0, + "content": "From \\(I\\), we first estimate the object pose as the azimuth and elevation angles, \\(\\alpha^a\\) and \\(\\alpha^e\\), respectively. To this end, we use a ResNet-18 [14] network on \\(I\\), pre-trained on synthetic rendered shapes to classify \\(\\alpha^a\\) and \\(\\alpha^e\\) into 12 and 5 bins for a coarse rotation estimate. For finer-grained reasoning, we predict normalized object coordinates [45] \\(I_{\\mathrm{NOC}}\\), dense correspondences from the object pixels in \\(I\\) to the canonical space of the object. For NOC prediction, we use a UNet-style network with an EfficientNet-b4 [43] backbone, trained on synthetic rendered shape data." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.895, + 0.903 + ], + "angle": 0, + "content": "We then formulate our texture transfer optimization. We differentiably render our generated texture from initial pose estimate \\(\\alpha^a\\) and \\(\\alpha^e\\) to produce the rendered image produced from local neural field \\(\\psi X\\). Since we optimize for perceptual similarity, we employ a style loss [13] in a global and" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.958 + ], + "angle": 0, + "content": "8921" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.308, + 0.106 + ], + "angle": 0, + "content": "local fashion to compare \\(X\\) and \\(I\\)." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.107, + 0.468, + 0.122 + ], + "angle": 0, + "content": "We then optimize for latent texture code \\(z\\) with the loss:" + }, + { + "type": "equation", + "bbox": [ + 0.078, + 0.129, + 0.47, + 0.233 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} L = w _ {g l o b} \\sum_ {h = 1} ^ {N _ {h}} \\sum_ {l = 1} ^ {N _ {l}} L _ {g l o b} \\left(I ^ {h, l}, X ^ {h, l}\\right) \\\\ + w _ {p a t c h} \\sum_ {p = 1} ^ {N _ {p}} \\sum_ {h = 1} ^ {N _ {h}} \\sum_ {l = 1} ^ {N _ {l}} L _ {p a t c h} \\left(I _ {p} ^ {h, l} (x, y), X _ {p} ^ {h, l} \\left(x ^ {\\prime}, y ^ {\\prime}\\right)\\right), \\tag {2} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.241, + 0.471, + 0.286 + ], + "angle": 0, + "content": "where \\( L_{glob} \\) denotes a global style loss, \\( L_{patch} \\) a local patch-based style loss, and \\( w_{glob} \\) and \\( w_{patch} \\) constants to balance the loss values." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.304, + 0.47, + 0.38 + ], + "angle": 0, + "content": "Global style loss. \\( L_{glob} \\) considers the full images \\( I \\) and \\( X \\) at \\( N_h = 3 \\) resolution levels (original, half, and quarter resolution): \\( I^h \\) and \\( X^h \\), \\( h \\in [1,2,3] \\). The global style loss is then computed on each pair \\( (X^h, I^h) \\) on \\( N_l = 5 \\) VGG feature layers." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.398, + 0.471, + 0.624 + ], + "angle": 0, + "content": "Patch style losses. Since the precise structure of the object in \\(I\\) may not match with that of \\(X\\) (e.g. geometry mismatch or inconsistent pose prediction), we further employ local style losses on image patches. We extract \\(N_{p} = 2\\) patches \\(I_{p}(x,y)\\) from \\(I\\) randomly per iteration, located at patch centers \\((x,y)\\) within the object. We then use the corresponding NOC estimate at the patch location, \\(I_{\\mathrm{NOC}}(x,y)\\), and find a corresponding patch \\(X_{p}(x^{\\prime},y^{\\prime})\\) where \\((x^{\\prime},y^{\\prime})\\) is the pixel location whose shape NOC is closest to \\(I_{\\mathrm{NOC}}(x,y)\\) w.r.t. \\(\\ell_2\\) distance. Note that since \\(X\\) has been rendered from a shape mesh, we can use ground truth shape NOCs for \\(X\\), and only require predicted NOCs for \\(I\\). This provides a coarse correspondence between patches to guide the style loss. Similar to \\(L_{glob}\\), we apply \\(L_{patch}\\) at \\(N_{h} = 3\\) resolution levels and with \\(N_{l} = 5\\) VGG feature layers." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.642, + 0.47, + 0.733 + ], + "angle": 0, + "content": "Face feature refinement. With texture code \\( z \\) optimized from Equation 2, we further allow for texture refinement by unfreezing the last two face convolutional layers in the texture generator. We optimize for refined weights in the surface features using only \\( L_{patch} \\), which enables better capturing of local detail in \\( I \\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.47, + 0.84 + ], + "angle": 0, + "content": "Implementation Details Our Mesh2Tex model is implemented using PyTorch and trained using an Adam [23] optimizer with learning rates of 1e-4, 12e-4, 1e-4, 14e-4 for the encoder, generator, neural field \\(\\psi\\) parameters and both discriminators, respectively. Mesh2Tex is trained on 2 NVIDIA A6000s for 50k iterations (\\(\\sim\\) 100 hours) until convergence." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.468, + 0.901 + ], + "angle": 0, + "content": "At test-time, we optimize latent codes for 100 iterations and refined weights for additional 300 iterations, which takes \\(\\sim 400\\)s in total. During texture optimization, we extract \\(64 \\times 64\\) patches. We provide further details in the supplemental." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.091, + 0.587, + 0.106 + ], + "angle": 0, + "content": "4. Results" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.117, + 0.894, + 0.179 + ], + "angle": 0, + "content": "We evaluate the texture generation capabilities of Mesh2Tex on unconditional generation and image-based texture generation, on both synthetic and real data. For both scenarios, our texture generation is trained from real images." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.207, + 0.895, + 0.419 + ], + "angle": 0, + "content": "Datasets. For evaluation, we use object geometry from ShapeNet [4] for texturing, and real-world query images from ScanNet [8] for chairs, and from CompCars [49] for cars. For synthetic experiments requiring exact geometric matches, we use ShapeNet textured objects and render query image views. For real image queries with close matching geometry, we use Scan2CAD [1] annotations for chair meshes to ScanNet images. For CompCars, we use the coarse pose information (front, back, left, right, etc.) to estimate close image alignments. During training, poses are rendered to coarsely approximate the distribution of real train images (e.g., for cars, 8 poses representing front, back, left, right, front-left, front-right, back-left, and back-right; for chairs, random poses from PhotoShape pose estimates)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.42, + 0.894, + 0.511 + ], + "angle": 0, + "content": "Note that all methods, except GET3D, were trained with the same set of ShapeNet meshes, and images from PhotoShape [34] and CompCars [49] for chairs and cars. GET3D requires a much denser sampling of images per shape rather than a single view per shape, so we instead compare with the authors' released pre-trained GET3D model." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.54, + 0.895, + 0.768 + ], + "angle": 0, + "content": "Evaluation metrics. We evaluate the perceptual quality of our generated textures with several metrics. To measure the realistic quality of the textures, we compare rendered views of generated textures on various shapes to real-world images, using the standard FID [16] and KID [2] scores used for assessing generated image quality. For FID and KID evaluation, we use real images from PhotoShape [34] and CompCars [49] for chairs and cars, respectively, and 6 rendered views from each synthesized textured shape. Additionally, for texture transfer from a single image, we compute CLIP [36] similarity as cosine distances between the query image and rendered texture. In synthetic experiment setups where exact geometric matches are available, we further compute an LPIPS [51] perceptual metric between synthesized views and the query image." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Baselines. We compare with several state-of-the-art texturing methods leveraging various texture representations: Yu et. al. [50] learns texture generation on a UV map parameterization, EG3D [3] leverages an efficient triplane representation for view synthesis, Texturify [42] generates per-face colors on a mesh, and GET3D [11] jointly estimates color and geometry with triplane representations." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8922" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.084, + 0.089, + 0.468, + 0.378 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.388, + 0.472, + 0.434 + ], + "angle": 0, + "content": "Figure 5: Unconditional texturing for meshes from ShapeNet [4], in comparison with state of the art. Our approach generates more realistic, detailed textures." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.463, + 0.469, + 0.558 + ], + "angle": 0, + "content": "
MethodParameterizationChairsCars
FIDKIDFIDKID
EG3DTri-plane Implicit36.452.1583.115.95
Yu et al.UV38.982.4673.635.77
GET3DTri-plane Implicit46.203.0289.626.92
Texturify4-RoSy Field31.081.7559.554.97
Ours4-RoSy Implicit Field30.011.6941.353.41
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.568, + 0.472, + 0.614 + ], + "angle": 0, + "content": "Table 1: Unconditional texture generation for 3D shapes. Our mesh-field approach outperforms state of the art in generation quality. The KID values are scaled by \\(10^{2}\\)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.642, + 0.379, + 0.658 + ], + "angle": 0, + "content": "4.1. Unconditional Texture Generation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.667, + 0.472, + 0.743 + ], + "angle": 0, + "content": "Table 1 and Figure 5 show quantitative and qualitative comparisons of unconditional texture generation to state of the art. Our hybrid mesh-field texture representation enables richer texture generation with finer-scale details than state-of-the-art baselines." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.755, + 0.405, + 0.773 + ], + "angle": 0, + "content": "4.2. Texture Transfer from a Single Image" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.781, + 0.471, + 0.903 + ], + "angle": 0, + "content": "We further evaluate texturing of objects from image queries, which opens up new possibilities in the content creation process. We consider both synthetic image queries, which enable texturing of exact geometric matches, as well as real image queries, where no object geometry matches exactly to the queries. For all baselines, we apply a similar texture optimization as our approach, leveraging global and patch-style losses without NOC guidance. During test-time" + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.09, + 0.889, + 0.413 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.423, + 0.896, + 0.515 + ], + "angle": 0, + "content": "Figure 6: Texture transfer from synthetic image queries to exact shape geometry with unknown image alignment. Mesh2Tex produces more geometrically consistent texturing with finer-resolution details captured in our mesh-field texture representation. Note that GET3D models both geometry and color, resulting in possible geometric changes." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.553, + 0.895, + 0.614 + ], + "angle": 0, + "content": "optimization in texture transfer experiments, we consider settings of known/unknown shape and pose for image queries, but we use the same adversarially trained model for all test-time experiments." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.632, + 0.81, + 0.648 + ], + "angle": 0, + "content": "4.2.1 Synthetic Image Query Experiments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.656, + 0.895, + 0.779 + ], + "angle": 0, + "content": "Exact geometry and known image alignment. We evaluate texture generation from a single image query to exactly matching object geometry with known image alignment in Tables 2 and 3, which measure the distribution quality and perceptual match to the query image, respectively. The optimization through our high-fidelity texture manifold enables more detailed texturing to match to various texture changes in the query image, in comparison to baselines." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Exact geometry and unknown image alignment. We evaluate texture generation from a single image query where the pose of the shape in the input query is unknown. Quantitative evaluation with state of the art is shown in Tables 4 and 5, which measure the distribution quality and perceptual match to the query image, respectively. Figure 6 visualizes qualitative comparisons. For GET3D, we do not evaluate" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8923" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.097, + 0.09, + 0.452, + 0.429 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.44, + 0.472, + 0.501 + ], + "angle": 0, + "content": "Figure 7: Texture transfer from real images (ScanNet) to closely matching shape geometry (ShapeNet). Despite inexact geometry and pose, Mesh2Tex produces perceptually consistent texturing." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.539, + 0.469, + 0.57 + ], + "angle": 0, + "content": "LPIPS, as it can produce geometric changes resulting in an inexact geometry match to the query." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.57, + 0.47, + 0.646 + ], + "angle": 0, + "content": "Even with exact geometry, the unknown image alignment poses a notable challenge, resulting in degraded performance in the baselines. Our approach maintains more robustness due to the NOC guidance in our patch loss during texture optimization, producing more plausible texture generation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.663, + 0.47, + 0.798 + ], + "angle": 0, + "content": "Texture transfer. We evaluate texture transfer experiments from a single image query to an arbitrary shape of a different geometry than the input query. Tables 6 and 7 compare our approach to state of the art. This challenging scenario of differing geometry results in a performance drop in all methods; however, due to our NOC-guided style optimization on a mesh-field texture representation, Mesh2Tex can produce textures on novel shape geometry with greater coherency and finer details than baselines." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.817, + 0.353, + 0.833 + ], + "angle": 0, + "content": "4.2.2 Real Image Query Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Closely-matching geometry and image alignment. We evaluate texturing from a single real-world image, where the shape geometry to be textured and image alignment are close (as we cannot guarantee an exact match to real-world" + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.089, + 0.892, + 0.216 + ], + "angle": 0, + "content": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
FIDKIDFIDKIDFIDKID
EG3D146.69.49297.920.82318.827.39
Yu et al.153.110.2289.418.88329.828.60
GET3D265.626.67248.815.57336.538.74
Texturify155.910.94301.420.63342.233.65
Ours115.45.38165.56.84309.726.50
" + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.227, + 0.895, + 0.304 + ], + "angle": 0, + "content": "Table 2: Evaluation on aligned queried texture generation with image queries from rendered ShapeNet chairs and cars, as well as real-world images from ScanNet chairs. Mesh2Tex generates more realistic textures from single-image queries. The KID values are scaled by \\(10^{2}\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.329, + 0.892, + 0.466 + ], + "angle": 0, + "content": "images). We compare with state of the art in Tables 2 and 3. In the real-world setting, view-dependent effects in real images (e.g., specular highlights, reflections) pose a notable challenge in evaluating texture optimization. With close but inexact geometry and alignment, our method can still produce textures that are consistent with the image queries due to NOC-guided optimization, while baseline methods struggle to transfer textures from incomplete and cluttered real-world objects." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.485, + 0.895, + 0.592 + ], + "angle": 0, + "content": "Closely-matching geometry and unknown image alignment. We further consider texturing from a single real-world image to close shape geometry with unknown image alignment. We show qualitative results in Figure 7 and quantitative evaluation in Tables 4 and 5. Our NOC-guided optimization through our texture manifold generates more perceptually representative textures." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.61, + 0.895, + 0.761 + ], + "angle": 0, + "content": "Texture transfer. Finally, we evaluate the challenging texture transfer scenario from a single real-world image from ScanNet [8] to an arbitrary ShapeNet [4] mesh of the same class category. This reflects potential texturing applications from users who wish to use an inspirational image to generate texturing on a given shape. We show a quantitative comparison in Tables 6 and 7, and qualitative results in Figure 8. Our mesh-field texture representation maintains more detail with NOC-guided patch loss to provide more robustness during optimization." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.762, + 0.892, + 0.838 + ], + "angle": 0, + "content": "Generated textures may differ from input images in Figs. 7 and 8 since shape geometry and poses differ between the shape to be textured and the query image. Thus, we cannot leverage any 1-1 correspondences, instead optimizing for patch-based perceptual similarity." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.847, + 0.736, + 0.864 + ], + "angle": 0, + "content": "4.3. Applicability to real scans" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.871, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Our method can also be easily applied to real scanned shapes, by applying QuadriFlow [18] to convert Marching" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8924" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.089, + 0.47, + 0.407 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.417, + 0.473, + 0.496 + ], + "angle": 0, + "content": "Figure 8: Texture transfer from real images (ScanNet, CompCars) to arbitrary shape geometry of the same class category (ShapeNet). Under this challenging scenario, our NOC-guided patch optimization enables plausible texturing for image queries." + }, + { + "type": "image", + "bbox": [ + 0.093, + 0.524, + 0.454, + 0.613 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.626, + 0.471, + 0.673 + ], + "angle": 0, + "content": "Figure 9: Texturing on real scanned objects from Redwood dataset. Mesh2Tex is able to generate consistent textures for non-synthetic geometry without finetuning." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.713, + 0.472, + 0.76 + ], + "angle": 0, + "content": "Cubes meshes to a quad mesh input. Fig. 9 shows our texturing of scanned shapes from the Redwood [6] dataset based on real ScanNet image queries." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.771, + 0.19, + 0.787 + ], + "angle": 0, + "content": "4.4. Ablations" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.472, + 0.903 + ], + "angle": 0, + "content": "What is the impact of our mesh-field representation for texture generation? Texturify [42] represents a per-face mesh color generation approach and the texturing results in coarse alignment of geometry and color features, while we introduce a shared barycentric neural field to capture high-fidelity details. Figure 5 shows our much finer-level detail generation, particularly for complex textures on cars." + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.089, + 0.895, + 0.214 + ], + "angle": 0, + "content": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
CLIPLPIPSCLIPLPIPSCLIP
EG3D89.8716.4183.2715.6982.86
Yu et al.89.7316.2684.3314.8382.93
GET3D85.00-81.38-78.52
Texturify89.2216.2383.8214.6981.71
Ours92.2714.6485.9114.7784.28
" + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.223, + 0.895, + 0.3 + ], + "angle": 0, + "content": "Table 3: Evaluation on aligned queried texture generation with image queries from rendered ShapeNet chairs and cars, as well as real-world images from ScanNet chairs. Our texture transfer optimization produces more perceptually representative texturing results." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.328, + 0.895, + 0.494 + ], + "angle": 0, + "content": "What is the impact of patch style loss in the texture optimization process? Table 8 shows that our patch-based style loss significantly improves texture transfer optimization performance, allowing for the capture of more local detail and robustness to mismatches to the query image. The patch-based optimization enables better capture of texture differences in shape parts than when only using the whole image. Namely, ablating patch style loss results in texture leaks between parts of different colors, an inability to capture textures of fine structures such as thin chair legs, and artifacts around texture-background borders." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.495, + 0.895, + 0.6 + ], + "angle": 0, + "content": "What is the impact of NOC guidance for the patch style loss? In Table 8, we see that the NOC guidance helps to improve the perceptual quality of results by establishing coarse correspondence to the query image. The NOC guidance largely affects local texture changes inherent to small-scale and thin parts (e.g., chair arms, legs), while only global style is captured without NOCs." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.602, + 0.895, + 0.708 + ], + "angle": 0, + "content": "What is the effect of surface feature optimization? Following latent texture code optimization, we allow for surface features in the texture generator to further be optimized, which produces slightly improved local texture detail, as shown in Table 8. Optimizing for surface features allows for non-harmful and small extending the flexibility of texture generation to better express high-contrast textures." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.709, + 0.892, + 0.77 + ], + "angle": 0, + "content": "What is the effect of global style loss? Table 8 shows that without our global style loss, the consistency of texture transfer is severely reduced. The single patch-based style loss enhances similarity to queries locally, but not globally." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.771, + 0.895, + 0.83 + ], + "angle": 0, + "content": "Following latent texture code optimization, we allow for surface features in the texture generator to further be optimized, which produces slightly improved local texture detail, as shown in Table 8." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.832, + 0.895, + 0.848 + ], + "angle": 0, + "content": "We refer to the supplemental for qualitative ablation analysis." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Limitations. Mesh2Tex offers a promising step towards conditional mesh texturing from a single image, though vari-" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8925" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.089, + 0.468, + 0.216 + ], + "angle": 0, + "content": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
FIDKIDFIDKIDFIDKID
EG3D155.29.13326.824.48319.427.18
Yu et al.160.09.88343.332.71327.128.20
GET3D271.926.54254.416.63337.338.76
Texturify174.211.74344.225.34333.328.81
Ours121.15.08165.86.77311.926.73
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.226, + 0.472, + 0.304 + ], + "angle": 0, + "content": "Table 4: Evaluation on unaligned queried texture generation with image queries from rendered ShapeNet chairs and cars, as well as real images from ScanNet chairs. Mesh2Tex maintains more realistic texture details than state of the art. The KID values are scaled by \\(10^{2}\\)." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.333, + 0.468, + 0.455 + ], + "angle": 0, + "content": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
CLIPLPIPSCLIPLPIPSCLIP
EG3D89.5116.8381.9316.1483.40
Yu et al.88.9816.8179.3521.8482.67
GET3D84.66-81.54-79.02
Texturify88.2416.8280.4515.4282.26
Ours91.5714.9685.4214.9784.28
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.467, + 0.472, + 0.545 + ], + "angle": 0, + "content": "Table 5: Evaluation on unaligned queried texture generation to ShapeNet chairs and cars from rendered ShapeNet objects as well as real-world image queries from ScanNet chairs. Our NOC-guided patch style loss maintains more robustness to the unknown image alignment." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.573, + 0.468, + 0.665 + ], + "angle": 0, + "content": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNetCars CompCars
FIDKIDFIDKIDFIDKIDFIDKID
EG3D297.428.53343.626.57355.233.31352.339.15
Yu et al.303.429.10351.126.75362.634.20385.451.37
GET3D--------
Texturify307.929.63357.127.05370.434.85264.729.23
Ours276.726.17194.510.11348.532.33203.721.48
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.676, + 0.472, + 0.768 + ], + "angle": 0, + "content": "Table 6: Evaluation on texture transfer to ShapeNet chairs and cars from rendered ShapeNet objects as well as real-world image queries from ScanNet chairs and CompCars cars. In this challenging scenario, our mesh-field representation retains more realistic detail in texture optimization. The KID values are scaled by \\(10^{2}\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.471, + 0.903 + ], + "angle": 0, + "content": "ous limitations remain. For instance, our approach does not explicitly model semantics, potentially leading to distortions in texture in semantically meaningful areas (e.g., spokes of a car wheel). Additionally, a more explicit characterization of the texture distribution could enable probabilistic sampling when input queries may be occluded or incomplete." + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.089, + 0.892, + 0.206 + ], + "angle": 0, + "content": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNetCars CompCars
CLIPCLIPCLIPCLIP
EG3D81.6280.7281.5468.18
Yu et al.81.3178.6981.2164.76
GET3D----
Texturify80.7078.5980.9966.93
Ours83.4782.2081.9577.71
" + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.217, + 0.895, + 0.295 + ], + "angle": 0, + "content": "Table 7: Evaluation on texture transfer to ShapeNet chairs and cars from rendered ShapeNet objects as well as real-world image queries from ScanNet chairs and CompCars cars. Our NOC-guided patch style loss enables better characterization of the input query image for texturing." + }, + { + "type": "table", + "bbox": [ + 0.549, + 0.31, + 0.846, + 0.433 + ], + "angle": 0, + "content": "
MethodChairs (unaligned) ShapeNet
FIDKIDCLIP
w/o NOC124.35.5391.09
w/o patches143.56.9189.68
w/o surf. features127.15.8090.70
w/o glob. style169.610.1288.05
Ours121.15.0891.57
" + }, + { + "type": "table_caption", + "bbox": [ + 0.498, + 0.443, + 0.895, + 0.505 + ], + "angle": 0, + "content": "Table 8: Ablation study on texture transfer optimization design. Our NOC guidance, patch style loss, and surface feature optimization help to improve generated texture quality. The KID values are scaled by \\(10^{2}\\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.533, + 0.619, + 0.55 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.56, + 0.895, + 0.728 + ], + "angle": 0, + "content": "We presented Mesh2Tex, which learns a texture manifold based on a hybrid mesh-field representation to generate realistic, high-quality textures on shape geometry from real-world imagery. Mesh2Tex enables test-time optimization for texture transfer from single image queries. Crucially, our NOC-guided local and global style loss enables optimization for perceptually matching textures on a 3D shape that does not require exact geometric matches to RGB image queries. We believe this opens up many new possibilities in texturing for content creation, enabling easy-to-capture images to be used as guidance for holistic shape texturing." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.739, + 0.895, + 0.801 + ], + "angle": 0, + "content": "Acknowledgements. This work was supported by the Bavarian State Ministry of Science and the Arts coordinated by the Bavarian Research Institute for Digital Transformation (bidt). ST was partially supported by a gift award from CISCO." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.818, + 0.597, + 0.835 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.508, + 0.845, + 0.895, + 0.903 + ], + "angle": 0, + "content": "[1] Armen Avetisyan, Manuel Dahnert, Angela Dai, Manolis Savva, Angel X. Chang, and Matthias Nießner. Scan2cad: Learning CAD model alignment in RGB-D scans. In IEEE Conference on Computer Vision and Pattern Recognition," + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8926" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.469, + 0.12 + ], + "angle": 0, + "content": "CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 2614-2623, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.122, + 0.47, + 0.163 + ], + "angle": 0, + "content": "[2] Mikołaj Binkowski, Danica J Sutherland, Michael Arbel, and Arthur Gretton. Demystifying mmd gans. arXiv preprint arXiv:1801.01401, 2018. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.165, + 0.471, + 0.234 + ], + "angle": 0, + "content": "[3] Eric R. Chan, Connor Z. Lin, Matthew A. Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas Guibas, Jonathan Tremblay, Sameh Khamis, Tero Karras, and Gordon Wetzstein. Efficient geometry-aware 3D generative adversarial networks. In arXiv, 2021. 2, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.236, + 0.471, + 0.303 + ], + "angle": 0, + "content": "[4] Angel X Chang, Thomas Funkhouser, Leonidas Guibas, Pat Hanrahan, Qixing Huang, Zimo Li, Silvio Savarese, Manolis Savva, Shuran Song, Hao Su, et al. Shapenet: An information-rich 3d model repository. arXiv preprint arXiv:1512.03012, 2015. 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.305, + 0.471, + 0.359 + ], + "angle": 0, + "content": "[5] Zhiqin Chen and Hao Zhang. Learning implicit fields for generative shape modeling. Proceedings of IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.362, + 0.47, + 0.417 + ], + "angle": 0, + "content": "[6] Sungjoon Choi, Qian-Yi Zhou, and Vladlen Koltun. Robust reconstruction of indoor scenes. In 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 5556-5565, 2015. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.42, + 0.471, + 0.473 + ], + "angle": 0, + "content": "[7] Manuel Dahnert, Ji Hou, Matthias Nießner, and Angela Dai. Panoptic 3d scene reconstruction from a single rgb image. In Thirty-Fifth Conference on Neural Information Processing Systems, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.476, + 0.471, + 0.545 + ], + "angle": 0, + "content": "[8] Angela Dai, Angel X. Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Niessner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In The IEEE Conference on Computer Vision and Pattern Recognition (CVPR), July 2017. 5, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.547, + 0.471, + 0.602 + ], + "angle": 0, + "content": "[9] Angela Dai, Yawar Siddiqui, Justus Thies, Julien Valentin, and Matthias Nießner. Spsg: Self-supervised photometric scene generation from rgb-d scans. In Proc. Computer Vision and Pattern Recognition (CVPR), IEEE, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.604, + 0.471, + 0.645 + ], + "angle": 0, + "content": "[10] Yu Deng, Jiaolong Yang, and Xin Tong. Deformed implicit field: Modeling 3d shapes with learned dense correspondence. In IEEE Computer Vision and Pattern Recognition, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.647, + 0.471, + 0.715 + ], + "angle": 0, + "content": "[11] Jun Gao, Tianchang Shen, Zian Wang, Wenzheng Chen, Kangxue Yin, Daiqing Li, Or Litany, Zan Gojcic, and Sanja Fidler. Get3d: A generative model of high quality 3d textured shapes learned from images. In Advances In Neural Information Processing Systems, 2022. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.717, + 0.471, + 0.758 + ], + "angle": 0, + "content": "[12] Lin Gao, Tong Wu, Yu-Jie Yuan, Ming-Xian Lin, Yu-Kun Lai, and Hao Zhang. Tm-net: Deep generative networks for textured meshes. 10 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.76, + 0.471, + 0.815 + ], + "angle": 0, + "content": "[13] Leon A Gatys, Alexander S Ecker, and Matthias Bethge. Image style transfer using convolutional neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2414-2423, 2016. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.817, + 0.471, + 0.871 + ], + "angle": 0, + "content": "[14] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.471, + 0.901 + ], + "angle": 0, + "content": "[15] Paul Henderson, Vagia Tsiminaki, and Christoph H Lampert. Leveraging 2d data to learn textured 3d mesh generation." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.893, + 0.121 + ], + "angle": 0, + "content": "In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7498-7507, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.123, + 0.894, + 0.19 + ], + "angle": 0, + "content": "[16] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in neural information processing systems, 30, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.193, + 0.894, + 0.274 + ], + "angle": 0, + "content": "[17] Jingwei Huang, Justus Thies, Angela Dai, Abhijit Kundu, Chiyu Jiang, Leonidas J Guibas, Matthias Niessner, and Thomas Funkhouser. Adversarial texture optimization from rgb-d scans. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1559-1568, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.277, + 0.894, + 0.347 + ], + "angle": 0, + "content": "[18] Jingwei Huang, Yichao Zhou, Matthias Niessner, Jonathan Richard Shewchuk, and Leonidas J Guibas. Quadriflow: A scalable and robust method for quadrangulation. In Computer Graphics Forum, volume 37, pages 147-160. Wiley Online Library, 2018. 4, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.349, + 0.893, + 0.389 + ], + "angle": 0, + "content": "[19] Ajay Jain, Ben Mildenhall, Jonathan T. Barron, Pieter Abbeel, and Ben Poole. Zero-shot text-guided object generation with dream fields. CVPR, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.391, + 0.893, + 0.459 + ], + "angle": 0, + "content": "[20] Krishna Murthy Jatavallabhula, Alihusein Kuwajerwala, Qiao Gu, Mohd Omama, Tao Chen, Shuang Li, Ganesh Iyer, Soroush Saryazdi, Nikhil Keetha, Ayush Tewari, et al. Conceptfusion: Open-set multimodal 3d mapping. arXiv preprint arXiv:2302.07241, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.462, + 0.893, + 0.516 + ], + "angle": 0, + "content": "[21] Xie Jianwen, Yifei Xu, Zilong Zheng, Song Zhu, and Ying-nian Wu. Generative pointnet: Energy-based learning on unordered point sets for 3d generation, reconstruction and classification. 04 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.519, + 0.893, + 0.56 + ], + "angle": 0, + "content": "[22] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of stylegan. CVPR, 2020. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.562, + 0.893, + 0.589 + ], + "angle": 0, + "content": "[23] Diederik P. Kingma and Jimmy Ba. Adam: A method for stochastic optimization. CoRR, abs/1412.6980, 2014. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.591, + 0.894, + 0.659 + ], + "angle": 0, + "content": "[24] Juil Koo, Ian Huang, Panos Achlioptas, Leonidas J Guibas, and Minhyuk Sung. Partglot: Learning shape part segmentation from language reference games. In Proceedings of IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.661, + 0.893, + 0.73 + ], + "angle": 0, + "content": "[25] Weicheng Kuo, Anelia Angelova, Tsung-Yi Lin, and Angela Dai. Patch2cad: Patchwise embedding learning for in-the-wild shape retrieval from a single image. 2021 IEEE/CVF International Conference on Computer Vision (ICCV), pages 12569-12579, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.733, + 0.893, + 0.787 + ], + "angle": 0, + "content": "[26] Shitong Luo and Wei Hu. Diffusion probabilistic models for 3d point cloud generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), June 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.789, + 0.893, + 0.857 + ], + "angle": 0, + "content": "[27] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3d reconstruction in function space. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 4460-4470, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.86, + 0.893, + 0.901 + ], + "angle": 0, + "content": "[28] Oscar Michel, Roi Bar-On, Richard Liu, Sagie Benaim, and Rana Hanocka. Text2mesh: Text-driven neural stylization for meshes. arXiv preprint arXiv:2112.03221, 2021. 3" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8927" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.472, + 0.134 + ], + "angle": 0, + "content": "[29] Paritosh Mittal, Yen-Chi Cheng, Maneesh Singh, and Shubham Tulsiani. AutoSDF: Shape priors for 3d completion, reconstruction and generation. In CVPR, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.137, + 0.472, + 0.178 + ], + "angle": 0, + "content": "[30] Charlie Nash, Yaroslav Ganin, S. Eslami, and Peter Battaglia. *Polygon: An autoregressive generative model of 3d meshes.* 02 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.181, + 0.472, + 0.25 + ], + "angle": 0, + "content": "[31] Michael Oechsle, Lars Mescheder, Michael Niemeyer, Thilo Strauss, and Andreas Geiger. Texture fields: Learning texture representations in function space. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4531-4540, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.253, + 0.472, + 0.309 + ], + "angle": 0, + "content": "[32] Michael Oechsle, Lars Mescheder, Michael Niemeyer, Thilo Strauss, and Andreas Geiger. Texture fields: Learning texture representations in function space. In Proceedings IEEE International Conf. on Computer Vision (ICCV), 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.311, + 0.472, + 0.38 + ], + "angle": 0, + "content": "[33] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. Deepsdf: Learning continuous signed distance functions for shape representation. In 2019 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 165-174, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.383, + 0.472, + 0.438 + ], + "angle": 0, + "content": "[34] Keunhong Park, Konstantinos Rematas, Ali Farhadi, and Steven M. Seitz. Photoshape: Photorealistic materials for large-scale shape collections. ACM Trans. Graph., 37(6), Nov. 2018. 2, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.441, + 0.472, + 0.496 + ], + "angle": 0, + "content": "[35] Dario Pavllo, Jonas Kohler, Thomas Hofmann, and Aurelien Lucchi. Learning generative models of textured 3d meshes from real-world images. In IEEE/CVF International Conference on Computer Vision (ICCV), 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.499, + 0.472, + 0.582 + ], + "angle": 0, + "content": "[36] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International conference on machine learning, pages 8748-8763. PMLR, 2021. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.585, + 0.472, + 0.64 + ], + "angle": 0, + "content": "[37] Nikhila Ravi, Jeremy Reizenstein, David Novotny, Taylor Gordon, Wan-Yen Lo, Justin Johnson, and Georgia Gkioxari. Accelerating 3d deep learning with pytorch3d. arXiv:2007.08501, 2020.4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.643, + 0.472, + 0.699 + ], + "angle": 0, + "content": "[38] David Rozenberszki, Or Litany, and Angela Dai. Language-grounded indoor 3d semantic segmentation in the wild. In Proceedings of the European Conference on Computer Vision (ECCV), 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.702, + 0.472, + 0.77 + ], + "angle": 0, + "content": "[39] Shunsuke Saito, Zeng Huang, Ryota Natsume, Shigeo Morishima, Angjoo Kanazawa, and Hao Li. Pifu: Pixel-aligned implicit function for high-resolution clothed human digitization. In The IEEE International Conference on Computer Vision (ICCV), October 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.773, + 0.472, + 0.842 + ], + "angle": 0, + "content": "[40] Shunsuke Saito, Tomas Simon, Jason Saragih, and Hanbyul Joo. Pifuhd: Multi-level pixel-aligned implicit function for high-resolution 3d human digitization. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, June 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.472, + 0.9 + ], + "angle": 0, + "content": "[41] Aditya Sanghi, Hang Chu, Joseph G Lambourne, Ye Wang, Chin-Yi Cheng, and Marco Fumero. Clip-forge: Towards zero-shot text-to-shape generation. arXiv preprint arXiv:2110.02624, 2021. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.472, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.092, + 0.893, + 0.134 + ], + "angle": 0, + "content": "[42] Yawar Siddiqui, Justus Thies, Fangchang Ma, Qi Shan, Matthias Nießner, and Angela Dai. Texturify: Generating textures on 3d shape surfaces, 2022. 2, 4, 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.137, + 0.893, + 0.176 + ], + "angle": 0, + "content": "[43] Mingxing Tan and Quoc V. Le. Efficientnet: Rethinking model scaling for convolutional neural networks. In ICML, 2019. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.179, + 0.893, + 0.219 + ], + "angle": 0, + "content": "[44] Can Wang, Menglei Chai, Mingming He, Dongdong Chen, and Jing Liao. Clip-nerf: Text-and-image driven manipulation of neural radiance fields. ArXiv, abs/2112.05139, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.221, + 0.893, + 0.303 + ], + "angle": 0, + "content": "[45] He Wang, Srinath Sridhar, Jingwei Huang, Julien Valentin, Shuran Song, and Leonidas J Guibas. Normalized object coordinate space for category-level 6d object pose and size estimation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2642-2651, 2019. 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.305, + 0.893, + 0.388 + ], + "angle": 0, + "content": "[46] Qiangeng Xu, Weiyue Wang, Duygu Ceylan, Radomir Mech, and Ulrich Neumann. Disn: Deep implicit surface network for high-quality single-view 3d reconstruction. In H. Wallach, H. Larochelle, A. Beygelzimer, F. d'Alché-Buc, E. Fox, and R. Garnett, editors, Advances in Neural Information Processing Systems 32, pages 492-502. Curran Associates, Inc., 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.39, + 0.893, + 0.458 + ], + "angle": 0, + "content": "[47] Qiangeng Xu, Zexiang Xu, Julien Philip, Sai Bi, Zhixin Shu, Kalyan Sunkavalli, and Ulrich Neumann. Point-nerf: Point-based neural radiance fields. 2022 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 5428–5438, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.46, + 0.893, + 0.515 + ], + "angle": 0, + "content": "[48] Bangbang Yang, Chong Bao, Junyi Zeng, Hujun Bao, Yinda Zhang, Zhaopeng Cui, and Guofeng Zhang. Neumesh: Learning disentangled neural mesh-based implicit field for geometry and texture editing. 07 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.517, + 0.893, + 0.583 + ], + "angle": 0, + "content": "[49] Linjie Yang, Ping Luo, Chen Change Loy, and Xiaou Tang. A large-scale car dataset for fine-grained categorization and verification. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3973-3981, 2015. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.587, + 0.893, + 0.628 + ], + "angle": 0, + "content": "[50] Rui Yu, Yue Dong, Pieter Peers, and Xin Tong. Learning texture generators for 3d shape collections from internet photo sets. In *British Machine Vision Conference*, 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.63, + 0.893, + 0.671 + ], + "angle": 0, + "content": "[51] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In CVPR, 2018. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.672, + 0.893, + 0.714 + ], + "angle": 0, + "content": "[52] Qian-Yi Zhou and Vladlen Koltun. Color map optimization for 3d reconstruction with consumer depth cameras. ACM Transactions on Graphics, 33, 08 2014. 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.092, + 0.893, + 0.714 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8928" + } + ] +] \ No newline at end of file diff --git a/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/743afd5f-14b2-4965-bbeb-bded0a673761_origin.pdf b/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/743afd5f-14b2-4965-bbeb-bded0a673761_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..e0003e0d9913db548c6fe56f8086a0292c6767b1 --- /dev/null +++ b/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/743afd5f-14b2-4965-bbeb-bded0a673761_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:172f47e39a82ac517e69d190a04af75ffdedbd4ef09e41e2b04b001b4155fed4 +size 6013211 diff --git a/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/full.md b/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/full.md new file mode 100644 index 0000000000000000000000000000000000000000..b1af437ad03a7b7e5fb5ae5e07db9b71d9cd22aa --- /dev/null +++ b/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/full.md @@ -0,0 +1,313 @@ +# Mesh2Tex: Generating Mesh Textures from Image Queries + +Alexey Bokhovkin +Technical University of Munich + +aleksei.bokhovkin@tum.de + +Shubham Tulsiani +Carnegie Mellon University + +shubhtuls@cmu.edu + +Angela Dai +Technical University of Munich + +angela.dai@tum.de + +![](images/8296feaf5e377ed5113e2fbd562fd59894a85601a47335c82e8d3b0376f2da5b.jpg) +Figure 1: Mesh2Tex learns realistic object texturing on a shape geometry through a hybrid mesh-field texture representation supporting high-resolution texture generation on various shape meshes. Furthermore, our learned texture manifold supports texture transfer optimization from image queries without requiring any matching geometry or pose alignment to the image, producing perceptually consistent texturing in this challenging content creation scenario. + +![](images/98d115b7600e4fcc1169744912728cc1f28829d3c0b434b74110962a9cac1e34.jpg) + +![](images/20262dff57895213672ea8064178813438175c32c8762a14990a3dc55c11c4be.jpg) + +# Abstract + +Remarkable advances have been achieved recently in learning neural representations that characterize object geometry, while generating textured objects suitable for downstream applications and 3D rendering remains at an early stage. In particular, reconstructing textured geometry from images of real objects is a significant challenge – reconstructed geometry is often inexact, making realistic texturing a significant challenge. We present Mesh2Tex, which learns a realistic object texture manifold from uncorrelated collections of 3D object geometry and photorealistic RGB images, by leveraging a hybrid mesh-neural-field texture representation. Our texture representation enables compact encoding + +of high-resolution textures as a neural field in the barycentric coordinate system of the mesh faces. The learned texture manifold enables effective navigation to generate an object texture for a given 3D object geometry that matches to an input RGB image, which maintains robustness even under challenging real-world scenarios where the mesh geometry approximates an inexact match to the underlying geometry in the RGB image. Mesh2Tex can effectively generate realistic object textures for an object mesh to match real images observations towards digitization of real environments, significantly improving over previous state of the art. + +Project page: alexeybokhovkin.github.io/ mesh2tex/ + +# 1. Introduction + +The ability to obtain 3D representations of real-world objects lies at the core of many important applications in graphics, robotics, movies and video games, and mixed reality. Approaches tackling the tasks of 3D generation [33, 26, 21, 29, 30, 10] or single-view reconstruction [5, 27, 46, 25, 7] enable users to easily create digital 3D assets, either from scratch or conditioned on an image. However, these approaches primarily focus on generating/inferring the geometry of objects, and this alone is insufficient to capture realistic environments, which requires high-quality texturing. + +In this work, we propose Mesh2Tex tackle the complementary task of high-fidelity texture generation given known object geometry. In addition to allowing texturing generation for a given object mesh, Mesh2Tex also enables image-based texture synthesis – synthesizing textures that perceptually match a single RGB image observation. In contrast to existing appearance modeling works that characterize texture as a field over the volume of 3D space [3, 39, 40, 31], we observe that object textures lie on object surfaces, and instead generate textures only on the mesh surface, with a hybrid explicit-implicit texture representation that ties the texture field to the barycentric coordinates of the mesh faces. This produces textured meshes directly compatible with downstream applications and 3D rendering engines. + +As large quantities of high-quality textured 3D objects are very expensive to obtain, requiring countless hours of skilled artists' work, we train our texture generator with uncorrelated collections of 3D object geometry and photorealistic 2D images, leveraging differentiable rendering to optimize mesh textures at arbitrary resolutions to match the quality of real 2D images in an adversarial fashion. That is, we generate coarse features and colors for each mesh face, which are then refined to high-resolution textures through a neural field defined on the barycentric coordinates of each mesh face. This hybrid texture representation enables differentiable rendering for texturing on explicit mesh surfaces while exploiting the efficiency of neural field representations. + +Our learned texture generator can then be used to produce realistic textures to match an input RGB observation of an object, by optimizing over our learned texture manifold conditioned on the mesh geometry, to find a latent texturing that perceptually matches the RGB image. As state-of-the-art object geometry reconstructions are typically inexact (e.g., noise, oversmoothing, retrieval from a database), our learned texture manifold enables effective regularization over plausible textures which effectively capture the perceptual input while providing realistic texturing over the full object. We formulate a patch-based style loss to capture perceptual similarities between our optimized texture and the RGB image, guided by dense correspondence prediction to correlate them. Experiments demonstrate that we outperform state of the art + +in both unconditional texture generation as well as image-conditioned texture generation. + +In summary, our contributions are: + +- a new hybrid mesh-neural-field texture representation that enables diverse, realistic texture generation on object mesh geometry by tying a neural texture field to the barycentric coordinate system of the mesh faces. This enables learning a rich texture manifold from collections of uncorrelated real images and object meshes through adversarial differentiable rendering. +- our learned texture manifold enables effective inference-time optimization to texture an object mesh to perceptually match a single real-world RGB image; crucially, we maintain robustness to real-world scenarios of differing views and even geometry with a patch-based perceptual optimization guided by dense correspondences. + +# 2. Related Work + +Optimization-based Texturing. Various approaches have been proposed to texture 3D shapes by optimizing from aligned image views of the shape. The traditional optimization approach of Zhou et. al. [52] solves a global optimization for a mapping from observed RGB images onto reconstructed geometry. More recently, Huang et. al. [17] introduce a modern adversarial discriminator loss, coupled with differentiable rendering, to optimize for texture on reconstructed geometry to produce realistic texturing robust to camera pose misalignments in real-world RGB-D capture scenarios. PointNeRF [47] and NeuMesh [48] optimize for view-dependent features using distance-based interpolation from the k-nearest neighbor points/vertices; in contrast, we aim to design a method with view-independent texturing that enables robustness to entirely arbitrary viewpoints. While these methods can produce impressive texturing results, they require aligned 2D/3D data and cannot produce textures in unobserved regions. + +Learned Texture Completion and Generation. Learning-based methods have also explored generative texturing, aiming to learn generalized features for unconditional synthesis or conditional inpainting. Photoshop [34] proposes to learn material retrieval to apply materials to 3D shapes. Recently, several methods have been developed to generate textures on various representations: SPSG [9] produces per-voxel colors with an adversarial differentiable rendering formulation, Pavollo et. al. [35] learn texturing in the UV domain, and Henderson et. al. [15] and Texturify [42] propose to generate per-face mesh colors with variational and adversarial training, respectively. TM-NET [12] is basically the 2D approach for texture generation as it uses unfolded UV maps as the main representation, which is unable to generate + +![](images/b93da614410658cc6da2d5347b5a0be0f60fc03da525c3f744d018db1c5de053.jpg) +Figure 2: Method overview. Left: we first learn a texture generator for textures represented as a shared local neural field in the barycentric coordinate system of each mesh face. This enables the capture of high-resolution texture detail, while remaining tied to surface geometry, avoiding ambiguities of volumetric field representations. Our learned texture manifold can then be used for texture transfer from a single RGB query image, based on a correspondence-guided patch-based style loss to produce perceptually consistent texturing even for shapes with differing geometry and unknown image pose. + +![](images/fc629d3f54baabbaa5c6e717438f3d2aae02cc57e8dfed2a00e8d297068382d6.jpg) + +consistent textures near the seams. Moreover, this method uses explicit part information, which significantly simplifies the setup for geometry-aware texture generation. The recent success of neural implicit field representations has also inspired implicit texture field models [32, 3, 11]. Our approach aims to model texture on the surface of a mesh, coupled with the representation capacity of a shared implicit field per mesh face. + +Query-based 3D Understanding. The recent success of vision-language models such as CLIP [36] has sparked interest in query-guided 3D understanding from text and images. Text and image guidance have been exploited for knowledge distillation for 3D semantic understanding [24, 38, 20]. Various shape generation tasks have also been formulated with text queries, by leveraging CLIP as supervision [41, 19, 44]. In particular, Text2Mesh [28] leverages CLIP guidance for text-based texture optimization on 3D shapes. We formulate Mesh2Tex to support image-based queries for texture transfer optimization to various 3D shapes, to reflect potential practical texturing scenarios where images are largely easy to capture or find, with high visual specificity. We thus tackle challenges in geometric and pose misalignments from various potential image queries. + +# 3. Method + +# 3.1. Overview + +We aim to learn a high-quality texture manifold conditioned on a given shape mesh geometry, which supports unconditional texture generation as well as optimization within the texture manifold to fit to image queries for practical texturing scenarios. An overview of our approach is visualized in Figure 2. We propose to learn this texture manifold on a + +hybrid representation that combines a mesh representation with a neural field operating on the barycentric coordinates of each mesh face. Our texture generator then generates initial coarse features per-face for a given shape mesh, which are then refined by a shared neural field across the mesh faces. This enables high-resolution texture generation by sampling the neural field on the mesh surface. In the absence of a large-scale dataset of high-quality 3D textured shapes, we supervise the texture generation with an adversarial loss with photorealistic 2D images, through differentiable rendering. + +We can then traverse our learned texture manifold to generate textures for a given shape geometry to perceptually match to image queries. Since an RGB image query may be taken at an arbitrary camera pose, we estimate the object pose in the RGB image along with its normalized object coordinates [45] to guide the texture optimization. Furthermore, we must also support texture transfer scenarios, as having an exact geometric shape match for an arbitrary RGB image query cannot be assumed in practice. We thus employ both a global and local patch-based style loss to generate a realistic texture that perceptually matches the query image. + +# 3.2. Mesh-Field Texture Generation + +We learn a texture manifold on a mesh-field representation. Given a shape mesh $\mathcal{M}$ , we use a latent-variable conditioned encoder-decoder to obtain per-face features $F$ . We then employ a shared neural field $\psi$ that operates on each face to produce arbitrary-resolution texturing. High-quality texture generation is then learned by supervision with photorealistic 2D images in an adversarial fashion through differentiable rendering. Our texture generator training is shown in Figure 3. + +A shape mesh $\mathcal{M}$ is represented as a quadrilateral mesh; inspired by the hierarchical mesh representation of Textu + +rify [42], we also employ QuadriFlow [18] to parameterize shape meshes as hierarchies of 4-way rotationally symmetric (4-RoSy) fields. We can then leverage convolutional and pooling operators on the neighborhoods of each quad face, enabling encoding and decoding features on such mesh faces with arbitrary topologies. We employ an encoder-decoder face convolutional network $G$ on $\mathcal{M}$ , which takes as input geometric quad face features (per-face normals, fundamental forms, and curvature), and predicts per-face features $F_{c}$ . Similar to StyleGAN [22] we incorporate a latent texture code $z$ into the decoder through a mapping network. + +As we aim to generate high-quality textures not limited to the mesh face resolution, we leverage a neural field $\psi$ . $\psi$ takes as input a barycentric coordinate $p$ on a mesh face, along with mean face feature $F_{v}$ of all incident quad faces: + +$$ +\psi \left(p, b _ {1} F _ {v _ {1}} + b _ {2} F _ {v _ {2}} + b _ {3} F _ {v _ {3}}\right) = c \in \mathbf {R} _ {[ - 1, 1 ]} ^ {3}, \tag {1} +$$ + +where $\mathcal{A} = \{v_1, v_2, v_3\}$ is the triangle half of a quad face $\{v_1, v_2, v_4, v_3\}$ in which $p$ lies, $\{b_1, b_2, b_3\}$ are the barycentric coordinates of $p$ with respect to triangle $\mathcal{A}$ , and $c$ is the final output color. We can then generate arbitrary-resolution textures by densely sampling $\psi$ on each mesh face. + +To supervise the learning of this mesh-field texture manifold, we differentiably render our generated textures for an adversarial loss with photorealistic 2D images. To render the generated textures, we sample $\psi$ at the locations corresponding to each pixel in the rendered view. In addition to implicit field $\psi$ rendering, we also pass the output feature map $F_{c}$ into one convolutional layer and render it using PyTorch3D [37] differentiable renderer and supervise it similarly as a proxy loss. We then train the texture manifold in an end-to-end fashion using a non-saturating GAN loss with gradient penalty and path length regularization. + +During training, we do not use any paired geometry with rendered images and only use unpaired collections of real-world images and synthetic shapes. + +# 3.3. Texture Transfer from a Single Image + +Once learned, we can not only use our texture manifold for unconditional generation, but also importantly traverse through the manifold to produce shape texturing that matches to a query RGB image $I$ . This represents real-world texturing scenarios where a user may wish to texture a shape based on an easy-to-capture image inspiration. Here, notable challenges are lack of knowledge of the ground truth object pose in $I$ , and handling inexact geometric matches between the shape mesh to be textured and the object in $I$ – as it is not practical, nor always desirable, to assume the ability to reconstruct or retrieve the exact geometry of the object in an arbitrary image. We thus aim to produce textures on a shape to perceptually match an image $I$ in these challenging scenarios. Our texture transfer optimization is illustrated in Figure 4. + +![](images/0cd58eb7be127c44c750ee16710cbda8e5757cf3a38a92b7c351d95d351b67b5.jpg) +Figure 3: Mesh-field texture generation. We employ face convolutions following [42] for initial coarse feature generation, followed by a neural field that interprets the per-face features to produce refined color outputs at arbitrary locations on the mesh surface. The hybrid mesh-field texture generation is supervised in an adversarial fashion through differentiable rendering, with photorealistic 2D images representing the real distribution. + +![](images/cdb58652f794816070dfb59a6ac4423cd845e7b93cb106b671583cecbdcdcc21.jpg) +Figure 4: Texture transfer optimization from a single image. We traverse our learned texture manifold for texture transfer from a single RGB image query. Since image alignment may be unknown, we estimate a coarse pose along with finer-grained dense NOC correspondences. We leverage the NOCs to guide patch sampling for our patch-based style loss to produce texturing that perceptually matches to the query images, without requiring any exact geometric shape matches to the image. + +From $I$ , we first estimate the object pose as the azimuth and elevation angles, $\alpha^a$ and $\alpha^e$ , respectively. To this end, we use a ResNet-18 [14] network on $I$ , pre-trained on synthetic rendered shapes to classify $\alpha^a$ and $\alpha^e$ into 12 and 5 bins for a coarse rotation estimate. For finer-grained reasoning, we predict normalized object coordinates [45] $I_{\mathrm{NOC}}$ , dense correspondences from the object pixels in $I$ to the canonical space of the object. For NOC prediction, we use a UNet-style network with an EfficientNet-b4 [43] backbone, trained on synthetic rendered shape data. + +We then formulate our texture transfer optimization. We differentiably render our generated texture from initial pose estimate $\alpha^a$ and $\alpha^e$ to produce the rendered image produced from local neural field $\psi X$ . Since we optimize for perceptual similarity, we employ a style loss [13] in a global and + +local fashion to compare $X$ and $I$ . + +We then optimize for latent texture code $z$ with the loss: + +$$ +\begin{array}{l} L = w _ {g l o b} \sum_ {h = 1} ^ {N _ {h}} \sum_ {l = 1} ^ {N _ {l}} L _ {g l o b} \left(I ^ {h, l}, X ^ {h, l}\right) \\ + w _ {p a t c h} \sum_ {p = 1} ^ {N _ {p}} \sum_ {h = 1} ^ {N _ {h}} \sum_ {l = 1} ^ {N _ {l}} L _ {p a t c h} \left(I _ {p} ^ {h, l} (x, y), X _ {p} ^ {h, l} \left(x ^ {\prime}, y ^ {\prime}\right)\right), \tag {2} \\ \end{array} +$$ + +where $L_{glob}$ denotes a global style loss, $L_{patch}$ a local patch-based style loss, and $w_{glob}$ and $w_{patch}$ constants to balance the loss values. + +Global style loss. $L_{glob}$ considers the full images $I$ and $X$ at $N_h = 3$ resolution levels (original, half, and quarter resolution): $I^h$ and $X^h$ , $h \in [1,2,3]$ . The global style loss is then computed on each pair $(X^h, I^h)$ on $N_l = 5$ VGG feature layers. + +Patch style losses. Since the precise structure of the object in $I$ may not match with that of $X$ (e.g. geometry mismatch or inconsistent pose prediction), we further employ local style losses on image patches. We extract $N_{p} = 2$ patches $I_{p}(x,y)$ from $I$ randomly per iteration, located at patch centers $(x,y)$ within the object. We then use the corresponding NOC estimate at the patch location, $I_{\mathrm{NOC}}(x,y)$ , and find a corresponding patch $X_{p}(x^{\prime},y^{\prime})$ where $(x^{\prime},y^{\prime})$ is the pixel location whose shape NOC is closest to $I_{\mathrm{NOC}}(x,y)$ w.r.t. $\ell_2$ distance. Note that since $X$ has been rendered from a shape mesh, we can use ground truth shape NOCs for $X$ , and only require predicted NOCs for $I$ . This provides a coarse correspondence between patches to guide the style loss. Similar to $L_{glob}$ , we apply $L_{patch}$ at $N_{h} = 3$ resolution levels and with $N_{l} = 5$ VGG feature layers. + +Face feature refinement. With texture code $z$ optimized from Equation 2, we further allow for texture refinement by unfreezing the last two face convolutional layers in the texture generator. We optimize for refined weights in the surface features using only $L_{patch}$ , which enables better capturing of local detail in $I$ . + +Implementation Details Our Mesh2Tex model is implemented using PyTorch and trained using an Adam [23] optimizer with learning rates of 1e-4, 12e-4, 1e-4, 14e-4 for the encoder, generator, neural field $\psi$ parameters and both discriminators, respectively. Mesh2Tex is trained on 2 NVIDIA A6000s for 50k iterations ( $\sim$ 100 hours) until convergence. + +At test-time, we optimize latent codes for 100 iterations and refined weights for additional 300 iterations, which takes $\sim 400$ s in total. During texture optimization, we extract $64 \times 64$ patches. We provide further details in the supplemental. + +# 4. Results + +We evaluate the texture generation capabilities of Mesh2Tex on unconditional generation and image-based texture generation, on both synthetic and real data. For both scenarios, our texture generation is trained from real images. + +Datasets. For evaluation, we use object geometry from ShapeNet [4] for texturing, and real-world query images from ScanNet [8] for chairs, and from CompCars [49] for cars. For synthetic experiments requiring exact geometric matches, we use ShapeNet textured objects and render query image views. For real image queries with close matching geometry, we use Scan2CAD [1] annotations for chair meshes to ScanNet images. For CompCars, we use the coarse pose information (front, back, left, right, etc.) to estimate close image alignments. During training, poses are rendered to coarsely approximate the distribution of real train images (e.g., for cars, 8 poses representing front, back, left, right, front-left, front-right, back-left, and back-right; for chairs, random poses from PhotoShape pose estimates). + +Note that all methods, except GET3D, were trained with the same set of ShapeNet meshes, and images from PhotoShape [34] and CompCars [49] for chairs and cars. GET3D requires a much denser sampling of images per shape rather than a single view per shape, so we instead compare with the authors' released pre-trained GET3D model. + +Evaluation metrics. We evaluate the perceptual quality of our generated textures with several metrics. To measure the realistic quality of the textures, we compare rendered views of generated textures on various shapes to real-world images, using the standard FID [16] and KID [2] scores used for assessing generated image quality. For FID and KID evaluation, we use real images from PhotoShape [34] and CompCars [49] for chairs and cars, respectively, and 6 rendered views from each synthesized textured shape. Additionally, for texture transfer from a single image, we compute CLIP [36] similarity as cosine distances between the query image and rendered texture. In synthetic experiment setups where exact geometric matches are available, we further compute an LPIPS [51] perceptual metric between synthesized views and the query image. + +Baselines. We compare with several state-of-the-art texturing methods leveraging various texture representations: Yu et. al. [50] learns texture generation on a UV map parameterization, EG3D [3] leverages an efficient triplane representation for view synthesis, Texturify [42] generates per-face colors on a mesh, and GET3D [11] jointly estimates color and geometry with triplane representations. + +![](images/d0013ebdc1f5400695e82c1fbd471b2120309b1ad95a9ff4add7b59ca0ca4734.jpg) +Figure 5: Unconditional texturing for meshes from ShapeNet [4], in comparison with state of the art. Our approach generates more realistic, detailed textures. + +
MethodParameterizationChairsCars
FIDKIDFIDKID
EG3DTri-plane Implicit36.452.1583.115.95
Yu et al.UV38.982.4673.635.77
GET3DTri-plane Implicit46.203.0289.626.92
Texturify4-RoSy Field31.081.7559.554.97
Ours4-RoSy Implicit Field30.011.6941.353.41
+ +Table 1: Unconditional texture generation for 3D shapes. Our mesh-field approach outperforms state of the art in generation quality. The KID values are scaled by $10^{2}$ . + +# 4.1. Unconditional Texture Generation + +Table 1 and Figure 5 show quantitative and qualitative comparisons of unconditional texture generation to state of the art. Our hybrid mesh-field texture representation enables richer texture generation with finer-scale details than state-of-the-art baselines. + +# 4.2. Texture Transfer from a Single Image + +We further evaluate texturing of objects from image queries, which opens up new possibilities in the content creation process. We consider both synthetic image queries, which enable texturing of exact geometric matches, as well as real image queries, where no object geometry matches exactly to the queries. For all baselines, we apply a similar texture optimization as our approach, leveraging global and patch-style losses without NOC guidance. During test-time + +![](images/7ddc1782154188f13c5cfd1743876dc8807d6cb5722cfc53f469bc9e940a71a3.jpg) +Figure 6: Texture transfer from synthetic image queries to exact shape geometry with unknown image alignment. Mesh2Tex produces more geometrically consistent texturing with finer-resolution details captured in our mesh-field texture representation. Note that GET3D models both geometry and color, resulting in possible geometric changes. + +optimization in texture transfer experiments, we consider settings of known/unknown shape and pose for image queries, but we use the same adversarially trained model for all test-time experiments. + +# 4.2.1 Synthetic Image Query Experiments + +Exact geometry and known image alignment. We evaluate texture generation from a single image query to exactly matching object geometry with known image alignment in Tables 2 and 3, which measure the distribution quality and perceptual match to the query image, respectively. The optimization through our high-fidelity texture manifold enables more detailed texturing to match to various texture changes in the query image, in comparison to baselines. + +Exact geometry and unknown image alignment. We evaluate texture generation from a single image query where the pose of the shape in the input query is unknown. Quantitative evaluation with state of the art is shown in Tables 4 and 5, which measure the distribution quality and perceptual match to the query image, respectively. Figure 6 visualizes qualitative comparisons. For GET3D, we do not evaluate + +![](images/549825ed01b8ce553467c83e10f6b6ebca9bd4009b0a44d3ede2f320263d4303.jpg) +Figure 7: Texture transfer from real images (ScanNet) to closely matching shape geometry (ShapeNet). Despite inexact geometry and pose, Mesh2Tex produces perceptually consistent texturing. + +LPIPS, as it can produce geometric changes resulting in an inexact geometry match to the query. + +Even with exact geometry, the unknown image alignment poses a notable challenge, resulting in degraded performance in the baselines. Our approach maintains more robustness due to the NOC guidance in our patch loss during texture optimization, producing more plausible texture generation. + +Texture transfer. We evaluate texture transfer experiments from a single image query to an arbitrary shape of a different geometry than the input query. Tables 6 and 7 compare our approach to state of the art. This challenging scenario of differing geometry results in a performance drop in all methods; however, due to our NOC-guided style optimization on a mesh-field texture representation, Mesh2Tex can produce textures on novel shape geometry with greater coherency and finer details than baselines. + +# 4.2.2 Real Image Query Experiments + +Closely-matching geometry and image alignment. We evaluate texturing from a single real-world image, where the shape geometry to be textured and image alignment are close (as we cannot guarantee an exact match to real-world + +
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
FIDKIDFIDKIDFIDKID
EG3D146.69.49297.920.82318.827.39
Yu et al.153.110.2289.418.88329.828.60
GET3D265.626.67248.815.57336.538.74
Texturify155.910.94301.420.63342.233.65
Ours115.45.38165.56.84309.726.50
+ +Table 2: Evaluation on aligned queried texture generation with image queries from rendered ShapeNet chairs and cars, as well as real-world images from ScanNet chairs. Mesh2Tex generates more realistic textures from single-image queries. The KID values are scaled by $10^{2}$ . + +images). We compare with state of the art in Tables 2 and 3. In the real-world setting, view-dependent effects in real images (e.g., specular highlights, reflections) pose a notable challenge in evaluating texture optimization. With close but inexact geometry and alignment, our method can still produce textures that are consistent with the image queries due to NOC-guided optimization, while baseline methods struggle to transfer textures from incomplete and cluttered real-world objects. + +Closely-matching geometry and unknown image alignment. We further consider texturing from a single real-world image to close shape geometry with unknown image alignment. We show qualitative results in Figure 7 and quantitative evaluation in Tables 4 and 5. Our NOC-guided optimization through our texture manifold generates more perceptually representative textures. + +Texture transfer. Finally, we evaluate the challenging texture transfer scenario from a single real-world image from ScanNet [8] to an arbitrary ShapeNet [4] mesh of the same class category. This reflects potential texturing applications from users who wish to use an inspirational image to generate texturing on a given shape. We show a quantitative comparison in Tables 6 and 7, and qualitative results in Figure 8. Our mesh-field texture representation maintains more detail with NOC-guided patch loss to provide more robustness during optimization. + +Generated textures may differ from input images in Figs. 7 and 8 since shape geometry and poses differ between the shape to be textured and the query image. Thus, we cannot leverage any 1-1 correspondences, instead optimizing for patch-based perceptual similarity. + +# 4.3. Applicability to real scans + +Our method can also be easily applied to real scanned shapes, by applying QuadriFlow [18] to convert Marching + +![](images/92bdb086cc612d4c851b461e1dda894964d6d3659ac19a99f642b550f2f53807.jpg) +Figure 8: Texture transfer from real images (ScanNet, CompCars) to arbitrary shape geometry of the same class category (ShapeNet). Under this challenging scenario, our NOC-guided patch optimization enables plausible texturing for image queries. + +![](images/4079c15c8602aea0b5d9034c78b98d4376cd101d065ee7bd017c98a40ebdb1d4.jpg) +Figure 9: Texturing on real scanned objects from Redwood dataset. Mesh2Tex is able to generate consistent textures for non-synthetic geometry without finetuning. + +Cubes meshes to a quad mesh input. Fig. 9 shows our texturing of scanned shapes from the Redwood [6] dataset based on real ScanNet image queries. + +# 4.4. Ablations + +What is the impact of our mesh-field representation for texture generation? Texturify [42] represents a per-face mesh color generation approach and the texturing results in coarse alignment of geometry and color features, while we introduce a shared barycentric neural field to capture high-fidelity details. Figure 5 shows our much finer-level detail generation, particularly for complex textures on cars. + +
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
CLIPLPIPSCLIPLPIPSCLIP
EG3D89.8716.4183.2715.6982.86
Yu et al.89.7316.2684.3314.8382.93
GET3D85.00-81.38-78.52
Texturify89.2216.2383.8214.6981.71
Ours92.2714.6485.9114.7784.28
+ +Table 3: Evaluation on aligned queried texture generation with image queries from rendered ShapeNet chairs and cars, as well as real-world images from ScanNet chairs. Our texture transfer optimization produces more perceptually representative texturing results. + +What is the impact of patch style loss in the texture optimization process? Table 8 shows that our patch-based style loss significantly improves texture transfer optimization performance, allowing for the capture of more local detail and robustness to mismatches to the query image. The patch-based optimization enables better capture of texture differences in shape parts than when only using the whole image. Namely, ablating patch style loss results in texture leaks between parts of different colors, an inability to capture textures of fine structures such as thin chair legs, and artifacts around texture-background borders. + +What is the impact of NOC guidance for the patch style loss? In Table 8, we see that the NOC guidance helps to improve the perceptual quality of results by establishing coarse correspondence to the query image. The NOC guidance largely affects local texture changes inherent to small-scale and thin parts (e.g., chair arms, legs), while only global style is captured without NOCs. + +What is the effect of surface feature optimization? Following latent texture code optimization, we allow for surface features in the texture generator to further be optimized, which produces slightly improved local texture detail, as shown in Table 8. Optimizing for surface features allows for non-harmful and small extending the flexibility of texture generation to better express high-contrast textures. + +What is the effect of global style loss? Table 8 shows that without our global style loss, the consistency of texture transfer is severely reduced. The single patch-based style loss enhances similarity to queries locally, but not globally. + +Following latent texture code optimization, we allow for surface features in the texture generator to further be optimized, which produces slightly improved local texture detail, as shown in Table 8. + +We refer to the supplemental for qualitative ablation analysis. + +Limitations. Mesh2Tex offers a promising step towards conditional mesh texturing from a single image, though vari- + +
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
FIDKIDFIDKIDFIDKID
EG3D155.29.13326.824.48319.427.18
Yu et al.160.09.88343.332.71327.128.20
GET3D271.926.54254.416.63337.338.76
Texturify174.211.74344.225.34333.328.81
Ours121.15.08165.86.77311.926.73
+ +Table 4: Evaluation on unaligned queried texture generation with image queries from rendered ShapeNet chairs and cars, as well as real images from ScanNet chairs. Mesh2Tex maintains more realistic texture details than state of the art. The KID values are scaled by $10^{2}$ . + +
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
CLIPLPIPSCLIPLPIPSCLIP
EG3D89.5116.8381.9316.1483.40
Yu et al.88.9816.8179.3521.8482.67
GET3D84.66-81.54-79.02
Texturify88.2416.8280.4515.4282.26
Ours91.5714.9685.4214.9784.28
+ +Table 5: Evaluation on unaligned queried texture generation to ShapeNet chairs and cars from rendered ShapeNet objects as well as real-world image queries from ScanNet chairs. Our NOC-guided patch style loss maintains more robustness to the unknown image alignment. + +
MethodChairs ShapeNetCars ShapeNetChairs ScanNetCars CompCars
FIDKIDFIDKIDFIDKIDFIDKID
EG3D297.428.53343.626.57355.233.31352.339.15
Yu et al.303.429.10351.126.75362.634.20385.451.37
GET3D--------
Texturify307.929.63357.127.05370.434.85264.729.23
Ours276.726.17194.510.11348.532.33203.721.48
+ +ous limitations remain. For instance, our approach does not explicitly model semantics, potentially leading to distortions in texture in semantically meaningful areas (e.g., spokes of a car wheel). Additionally, a more explicit characterization of the texture distribution could enable probabilistic sampling when input queries may be occluded or incomplete. + +Table 6: Evaluation on texture transfer to ShapeNet chairs and cars from rendered ShapeNet objects as well as real-world image queries from ScanNet chairs and CompCars cars. In this challenging scenario, our mesh-field representation retains more realistic detail in texture optimization. The KID values are scaled by $10^{2}$ . + +
MethodChairs ShapeNetCars ShapeNetChairs ScanNetCars CompCars
CLIPCLIPCLIPCLIP
EG3D81.6280.7281.5468.18
Yu et al.81.3178.6981.2164.76
GET3D----
Texturify80.7078.5980.9966.93
Ours83.4782.2081.9577.71
+ +Table 7: Evaluation on texture transfer to ShapeNet chairs and cars from rendered ShapeNet objects as well as real-world image queries from ScanNet chairs and CompCars cars. Our NOC-guided patch style loss enables better characterization of the input query image for texturing. + +
MethodChairs (unaligned) ShapeNet
FIDKIDCLIP
w/o NOC124.35.5391.09
w/o patches143.56.9189.68
w/o surf. features127.15.8090.70
w/o glob. style169.610.1288.05
Ours121.15.0891.57
+ +Table 8: Ablation study on texture transfer optimization design. Our NOC guidance, patch style loss, and surface feature optimization help to improve generated texture quality. The KID values are scaled by $10^{2}$ . + +# 5. Conclusion + +We presented Mesh2Tex, which learns a texture manifold based on a hybrid mesh-field representation to generate realistic, high-quality textures on shape geometry from real-world imagery. Mesh2Tex enables test-time optimization for texture transfer from single image queries. Crucially, our NOC-guided local and global style loss enables optimization for perceptually matching textures on a 3D shape that does not require exact geometric matches to RGB image queries. We believe this opens up many new possibilities in texturing for content creation, enabling easy-to-capture images to be used as guidance for holistic shape texturing. + +Acknowledgements. This work was supported by the Bavarian State Ministry of Science and the Arts coordinated by the Bavarian Research Institute for Digital Transformation (bidt). ST was partially supported by a gift award from CISCO. + +# References + +[1] Armen Avetisyan, Manuel Dahnert, Angela Dai, Manolis Savva, Angel X. Chang, and Matthias Nießner. Scan2cad: Learning CAD model alignment in RGB-D scans. In IEEE Conference on Computer Vision and Pattern Recognition, + +CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 2614-2623, 2019. 5 +[2] Mikołaj Binkowski, Danica J Sutherland, Michael Arbel, and Arthur Gretton. Demystifying mmd gans. arXiv preprint arXiv:1801.01401, 2018. 5 +[3] Eric R. Chan, Connor Z. Lin, Matthew A. Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas Guibas, Jonathan Tremblay, Sameh Khamis, Tero Karras, and Gordon Wetzstein. Efficient geometry-aware 3D generative adversarial networks. In arXiv, 2021. 2, 3, 5 +[4] Angel X Chang, Thomas Funkhouser, Leonidas Guibas, Pat Hanrahan, Qixing Huang, Zimo Li, Silvio Savarese, Manolis Savva, Shuran Song, Hao Su, et al. Shapenet: An information-rich 3d model repository. arXiv preprint arXiv:1512.03012, 2015. 5, 6, 7 +[5] Zhiqin Chen and Hao Zhang. Learning implicit fields for generative shape modeling. Proceedings of IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2019. 2 +[6] Sungjoon Choi, Qian-Yi Zhou, and Vladlen Koltun. Robust reconstruction of indoor scenes. In 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 5556-5565, 2015. 8 +[7] Manuel Dahnert, Ji Hou, Matthias Nießner, and Angela Dai. Panoptic 3d scene reconstruction from a single rgb image. In Thirty-Fifth Conference on Neural Information Processing Systems, 2021. 2 +[8] Angela Dai, Angel X. Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Niessner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In The IEEE Conference on Computer Vision and Pattern Recognition (CVPR), July 2017. 5, 7 +[9] Angela Dai, Yawar Siddiqui, Justus Thies, Julien Valentin, and Matthias Nießner. Spsg: Self-supervised photometric scene generation from rgb-d scans. In Proc. Computer Vision and Pattern Recognition (CVPR), IEEE, 2021. 2 +[10] Yu Deng, Jiaolong Yang, and Xin Tong. Deformed implicit field: Modeling 3d shapes with learned dense correspondence. In IEEE Computer Vision and Pattern Recognition, 2021. 2 +[11] Jun Gao, Tianchang Shen, Zian Wang, Wenzheng Chen, Kangxue Yin, Daiqing Li, Or Litany, Zan Gojcic, and Sanja Fidler. Get3d: A generative model of high quality 3d textured shapes learned from images. In Advances In Neural Information Processing Systems, 2022. 3, 5 +[12] Lin Gao, Tong Wu, Yu-Jie Yuan, Ming-Xian Lin, Yu-Kun Lai, and Hao Zhang. Tm-net: Deep generative networks for textured meshes. 10 2020. 2 +[13] Leon A Gatys, Alexander S Ecker, and Matthias Bethge. Image style transfer using convolutional neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2414-2423, 2016. 4 +[14] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 4 +[15] Paul Henderson, Vagia Tsiminaki, and Christoph H Lampert. Leveraging 2d data to learn textured 3d mesh generation. + +In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7498-7507, 2020. 2 +[16] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in neural information processing systems, 30, 2017. 5 +[17] Jingwei Huang, Justus Thies, Angela Dai, Abhijit Kundu, Chiyu Jiang, Leonidas J Guibas, Matthias Niessner, and Thomas Funkhouser. Adversarial texture optimization from rgb-d scans. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1559-1568, 2020. 2 +[18] Jingwei Huang, Yichao Zhou, Matthias Niessner, Jonathan Richard Shewchuk, and Leonidas J Guibas. Quadriflow: A scalable and robust method for quadrangulation. In Computer Graphics Forum, volume 37, pages 147-160. Wiley Online Library, 2018. 4, 7 +[19] Ajay Jain, Ben Mildenhall, Jonathan T. Barron, Pieter Abbeel, and Ben Poole. Zero-shot text-guided object generation with dream fields. CVPR, 2022. 3 +[20] Krishna Murthy Jatavallabhula, Alihusein Kuwajerwala, Qiao Gu, Mohd Omama, Tao Chen, Shuang Li, Ganesh Iyer, Soroush Saryazdi, Nikhil Keetha, Ayush Tewari, et al. Conceptfusion: Open-set multimodal 3d mapping. arXiv preprint arXiv:2302.07241, 2023. 3 +[21] Xie Jianwen, Yifei Xu, Zilong Zheng, Song Zhu, and Ying-nian Wu. Generative pointnet: Energy-based learning on unordered point sets for 3d generation, reconstruction and classification. 04 2020. 2 +[22] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of stylegan. CVPR, 2020. 4 +[23] Diederik P. Kingma and Jimmy Ba. Adam: A method for stochastic optimization. CoRR, abs/1412.6980, 2014. 5 +[24] Juil Koo, Ian Huang, Panos Achlioptas, Leonidas J Guibas, and Minhyuk Sung. Partglot: Learning shape part segmentation from language reference games. In Proceedings of IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 3 +[25] Weicheng Kuo, Anelia Angelova, Tsung-Yi Lin, and Angela Dai. Patch2cad: Patchwise embedding learning for in-the-wild shape retrieval from a single image. 2021 IEEE/CVF International Conference on Computer Vision (ICCV), pages 12569-12579, 2021. 2 +[26] Shitong Luo and Wei Hu. Diffusion probabilistic models for 3d point cloud generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), June 2021. 2 +[27] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3d reconstruction in function space. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 4460-4470, 2019. 2 +[28] Oscar Michel, Roi Bar-On, Richard Liu, Sagie Benaim, and Rana Hanocka. Text2mesh: Text-driven neural stylization for meshes. arXiv preprint arXiv:2112.03221, 2021. 3 + +[29] Paritosh Mittal, Yen-Chi Cheng, Maneesh Singh, and Shubham Tulsiani. AutoSDF: Shape priors for 3d completion, reconstruction and generation. In CVPR, 2022. 2 +[30] Charlie Nash, Yaroslav Ganin, S. Eslami, and Peter Battaglia. *Polygon: An autoregressive generative model of 3d meshes.* 02 2020. 2 +[31] Michael Oechsle, Lars Mescheder, Michael Niemeyer, Thilo Strauss, and Andreas Geiger. Texture fields: Learning texture representations in function space. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4531-4540, 2019. 2 +[32] Michael Oechsle, Lars Mescheder, Michael Niemeyer, Thilo Strauss, and Andreas Geiger. Texture fields: Learning texture representations in function space. In Proceedings IEEE International Conf. on Computer Vision (ICCV), 2019. 3 +[33] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. Deepsdf: Learning continuous signed distance functions for shape representation. In 2019 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 165-174, 2019. 2 +[34] Keunhong Park, Konstantinos Rematas, Ali Farhadi, and Steven M. Seitz. Photoshape: Photorealistic materials for large-scale shape collections. ACM Trans. Graph., 37(6), Nov. 2018. 2, 5 +[35] Dario Pavllo, Jonas Kohler, Thomas Hofmann, and Aurelien Lucchi. Learning generative models of textured 3d meshes from real-world images. In IEEE/CVF International Conference on Computer Vision (ICCV), 2021. 2 +[36] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International conference on machine learning, pages 8748-8763. PMLR, 2021. 3, 5 +[37] Nikhila Ravi, Jeremy Reizenstein, David Novotny, Taylor Gordon, Wan-Yen Lo, Justin Johnson, and Georgia Gkioxari. Accelerating 3d deep learning with pytorch3d. arXiv:2007.08501, 2020.4 +[38] David Rozenberszki, Or Litany, and Angela Dai. Language-grounded indoor 3d semantic segmentation in the wild. In Proceedings of the European Conference on Computer Vision (ECCV), 2022. 3 +[39] Shunsuke Saito, Zeng Huang, Ryota Natsume, Shigeo Morishima, Angjoo Kanazawa, and Hao Li. Pifu: Pixel-aligned implicit function for high-resolution clothed human digitization. In The IEEE International Conference on Computer Vision (ICCV), October 2019. 2 +[40] Shunsuke Saito, Tomas Simon, Jason Saragih, and Hanbyul Joo. Pifuhd: Multi-level pixel-aligned implicit function for high-resolution 3d human digitization. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, June 2020. 2 +[41] Aditya Sanghi, Hang Chu, Joseph G Lambourne, Ye Wang, Chin-Yi Cheng, and Marco Fumero. Clip-forge: Towards zero-shot text-to-shape generation. arXiv preprint arXiv:2110.02624, 2021. 3 + +[42] Yawar Siddiqui, Justus Thies, Fangchang Ma, Qi Shan, Matthias Nießner, and Angela Dai. Texturify: Generating textures on 3d shape surfaces, 2022. 2, 4, 5, 8 +[43] Mingxing Tan and Quoc V. Le. Efficientnet: Rethinking model scaling for convolutional neural networks. In ICML, 2019. 4 +[44] Can Wang, Menglei Chai, Mingming He, Dongdong Chen, and Jing Liao. Clip-nerf: Text-and-image driven manipulation of neural radiance fields. ArXiv, abs/2112.05139, 2021. 3 +[45] He Wang, Srinath Sridhar, Jingwei Huang, Julien Valentin, Shuran Song, and Leonidas J Guibas. Normalized object coordinate space for category-level 6d object pose and size estimation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2642-2651, 2019. 3, 4 +[46] Qiangeng Xu, Weiyue Wang, Duygu Ceylan, Radomir Mech, and Ulrich Neumann. Disn: Deep implicit surface network for high-quality single-view 3d reconstruction. In H. Wallach, H. Larochelle, A. Beygelzimer, F. d'Alché-Buc, E. Fox, and R. Garnett, editors, Advances in Neural Information Processing Systems 32, pages 492-502. Curran Associates, Inc., 2019. 2 +[47] Qiangeng Xu, Zexiang Xu, Julien Philip, Sai Bi, Zhixin Shu, Kalyan Sunkavalli, and Ulrich Neumann. Point-nerf: Point-based neural radiance fields. 2022 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 5428–5438, 2022. 2 +[48] Bangbang Yang, Chong Bao, Junyi Zeng, Hujun Bao, Yinda Zhang, Zhaopeng Cui, and Guofeng Zhang. Neumesh: Learning disentangled neural mesh-based implicit field for geometry and texture editing. 07 2022. 2 +[49] Linjie Yang, Ping Luo, Chen Change Loy, and Xiaou Tang. A large-scale car dataset for fine-grained categorization and verification. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3973-3981, 2015. 5 +[50] Rui Yu, Yue Dong, Pieter Peers, and Xin Tong. Learning texture generators for 3d shape collections from internet photo sets. In *British Machine Vision Conference*, 2021. 5 +[51] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In CVPR, 2018. 5 +[52] Qian-Yi Zhou and Vladlen Koltun. Color map optimization for 3d reconstruction with consumer depth cameras. ACM Transactions on Graphics, 33, 08 2014. 2 \ No newline at end of file diff --git a/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/images.zip b/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..bd0213ba508a278654bf6d631c60af30c492ed4a --- /dev/null +++ b/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c794f372ee5bf2fa7ee01d31ded9876e3078243ace8dfd1a6fd4a9282a5b8e07 +size 726987 diff --git a/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/layout.json b/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..2098563e5b5cb33f42ab17d1d092e9d9e68d3f8d --- /dev/null +++ b/2023/Mesh2Tex_ Generating Mesh Textures from Image Queries/layout.json @@ -0,0 +1,8595 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 115, + 103, + 479, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 115, + 103, + 479, + 121 + ], + "spans": [ + { + "bbox": [ + 115, + 103, + 479, + 121 + ], + "type": "text", + "content": "Mesh2Tex: Generating Mesh Textures from Image Queries" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 133, + 144, + 288, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 133, + 144, + 288, + 171 + ], + "spans": [ + { + "bbox": [ + 133, + 144, + 288, + 171 + ], + "type": "text", + "content": "Alexey Bokhovkin \nTechnical University of Munich" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 145, + 174, + 277, + 184 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 145, + 174, + 277, + 184 + ], + "spans": [ + { + "bbox": [ + 145, + 174, + 277, + 184 + ], + "type": "text", + "content": "aleksei.bokhovkin@tum.de" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 323, + 144, + 459, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 323, + 144, + 459, + 171 + ], + "spans": [ + { + "bbox": [ + 323, + 144, + 459, + 171 + ], + "type": "text", + "content": "Shubham Tulsiani \nCarnegie Mellon University" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 345, + 174, + 438, + 184 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 345, + 174, + 438, + 184 + ], + "spans": [ + { + "bbox": [ + 345, + 174, + 438, + 184 + ], + "type": "text", + "content": "shubhtuls@cmu.edu" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 219, + 192, + 374, + 219 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 219, + 192, + 374, + 219 + ], + "spans": [ + { + "bbox": [ + 219, + 192, + 374, + 219 + ], + "type": "text", + "content": "Angela Dai \nTechnical University of Munich" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 250, + 222, + 343, + 232 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 250, + 222, + 343, + 232 + ], + "spans": [ + { + "bbox": [ + 250, + 222, + 343, + 232 + ], + "type": "text", + "content": "angela.dai@tum.de" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 70, + 239, + 173, + 484 + ], + "blocks": [ + { + "bbox": [ + 70, + 239, + 173, + 484 + ], + "lines": [ + { + "bbox": [ + 70, + 239, + 173, + 484 + ], + "spans": [ + { + "bbox": [ + 70, + 239, + 173, + 484 + ], + "type": "image", + "image_path": "8296feaf5e377ed5113e2fbd562fd59894a85601a47335c82e8d3b0376f2da5b.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 45, + 488, + 547, + 537 + ], + "lines": [ + { + "bbox": [ + 45, + 488, + 547, + 537 + ], + "spans": [ + { + "bbox": [ + 45, + 488, + 547, + 537 + ], + "type": "text", + "content": "Figure 1: Mesh2Tex learns realistic object texturing on a shape geometry through a hybrid mesh-field texture representation supporting high-resolution texture generation on various shape meshes. Furthermore, our learned texture manifold supports texture transfer optimization from image queries without requiring any matching geometry or pose alignment to the image, producing perceptually consistent texturing in this challenging content creation scenario." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 184, + 239, + 347, + 485 + ], + "blocks": [ + { + "bbox": [ + 184, + 239, + 347, + 485 + ], + "lines": [ + { + "bbox": [ + 184, + 239, + 347, + 485 + ], + "spans": [ + { + "bbox": [ + 184, + 239, + 347, + 485 + ], + "type": "image", + "image_path": "98d115b7600e4fcc1169744912728cc1f28829d3c0b434b74110962a9cac1e34.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 359, + 239, + 522, + 485 + ], + "blocks": [ + { + "bbox": [ + 359, + 239, + 522, + 485 + ], + "lines": [ + { + "bbox": [ + 359, + 239, + 522, + 485 + ], + "spans": [ + { + "bbox": [ + 359, + 239, + 522, + 485 + ], + "type": "image", + "image_path": "20262dff57895213672ea8064178813438175c32c8762a14990a3dc55c11c4be.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 143, + 544, + 192, + 556 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 544, + 192, + 556 + ], + "spans": [ + { + "bbox": [ + 143, + 544, + 192, + 556 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 570, + 290, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 570, + 290, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 570, + 290, + 715 + ], + "type": "text", + "content": "Remarkable advances have been achieved recently in learning neural representations that characterize object geometry, while generating textured objects suitable for downstream applications and 3D rendering remains at an early stage. In particular, reconstructing textured geometry from images of real objects is a significant challenge – reconstructed geometry is often inexact, making realistic texturing a significant challenge. We present Mesh2Tex, which learns a realistic object texture manifold from uncorrelated collections of 3D object geometry and photorealistic RGB images, by leveraging a hybrid mesh-neural-field texture representation. Our texture representation enables compact encoding" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 545, + 547, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 545, + 547, + 676 + ], + "spans": [ + { + "bbox": [ + 304, + 545, + 547, + 676 + ], + "type": "text", + "content": "of high-resolution textures as a neural field in the barycentric coordinate system of the mesh faces. The learned texture manifold enables effective navigation to generate an object texture for a given 3D object geometry that matches to an input RGB image, which maintains robustness even under challenging real-world scenarios where the mesh geometry approximates an inexact match to the underlying geometry in the RGB image. Mesh2Tex can effectively generate realistic object textures for an object mesh to match real images observations towards digitization of real environments, significantly improving over previous state of the art." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 677, + 547, + 700 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 547, + 700 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 547, + 700 + ], + "type": "text", + "content": "Project page: alexeybokhovkin.github.io/ mesh2tex/" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8918" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 127, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 127, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 127, + 83 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 91, + 287, + 222 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 91, + 287, + 222 + ], + "spans": [ + { + "bbox": [ + 47, + 91, + 287, + 222 + ], + "type": "text", + "content": "The ability to obtain 3D representations of real-world objects lies at the core of many important applications in graphics, robotics, movies and video games, and mixed reality. Approaches tackling the tasks of 3D generation [33, 26, 21, 29, 30, 10] or single-view reconstruction [5, 27, 46, 25, 7] enable users to easily create digital 3D assets, either from scratch or conditioned on an image. However, these approaches primarily focus on generating/inferring the geometry of objects, and this alone is insufficient to capture realistic environments, which requires high-quality texturing." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 223, + 288, + 390 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 223, + 288, + 390 + ], + "spans": [ + { + "bbox": [ + 47, + 223, + 288, + 390 + ], + "type": "text", + "content": "In this work, we propose Mesh2Tex tackle the complementary task of high-fidelity texture generation given known object geometry. In addition to allowing texturing generation for a given object mesh, Mesh2Tex also enables image-based texture synthesis – synthesizing textures that perceptually match a single RGB image observation. In contrast to existing appearance modeling works that characterize texture as a field over the volume of 3D space [3, 39, 40, 31], we observe that object textures lie on object surfaces, and instead generate textures only on the mesh surface, with a hybrid explicit-implicit texture representation that ties the texture field to the barycentric coordinates of the mesh faces. This produces textured meshes directly compatible with downstream applications and 3D rendering engines." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 391, + 288, + 545 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 391, + 288, + 545 + ], + "spans": [ + { + "bbox": [ + 47, + 391, + 288, + 545 + ], + "type": "text", + "content": "As large quantities of high-quality textured 3D objects are very expensive to obtain, requiring countless hours of skilled artists' work, we train our texture generator with uncorrelated collections of 3D object geometry and photorealistic 2D images, leveraging differentiable rendering to optimize mesh textures at arbitrary resolutions to match the quality of real 2D images in an adversarial fashion. That is, we generate coarse features and colors for each mesh face, which are then refined to high-resolution textures through a neural field defined on the barycentric coordinates of each mesh face. This hybrid texture representation enables differentiable rendering for texturing on explicit mesh surfaces while exploiting the efficiency of neural field representations." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 545, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 545, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 545, + 288, + 713 + ], + "type": "text", + "content": "Our learned texture generator can then be used to produce realistic textures to match an input RGB observation of an object, by optimizing over our learned texture manifold conditioned on the mesh geometry, to find a latent texturing that perceptually matches the RGB image. As state-of-the-art object geometry reconstructions are typically inexact (e.g., noise, oversmoothing, retrieval from a database), our learned texture manifold enables effective regularization over plausible textures which effectively capture the perceptual input while providing realistic texturing over the full object. We formulate a patch-based style loss to capture perceptual similarities between our optimized texture and the RGB image, guided by dense correspondence prediction to correlate them. Experiments demonstrate that we outperform state of the art" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 305, + 72, + 547, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 547, + 95 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 547, + 95 + ], + "type": "text", + "content": "in both unconditional texture generation as well as image-conditioned texture generation." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 318, + 97, + 459, + 108 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 318, + 97, + 459, + 108 + ], + "spans": [ + { + "bbox": [ + 318, + 97, + 459, + 108 + ], + "type": "text", + "content": "In summary, our contributions are:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 118, + 547, + 281 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 317, + 118, + 547, + 201 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 118, + 547, + 201 + ], + "spans": [ + { + "bbox": [ + 317, + 118, + 547, + 201 + ], + "type": "text", + "content": "- a new hybrid mesh-neural-field texture representation that enables diverse, realistic texture generation on object mesh geometry by tying a neural texture field to the barycentric coordinate system of the mesh faces. This enables learning a rich texture manifold from collections of uncorrelated real images and object meshes through adversarial differentiable rendering." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 210, + 547, + 281 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 210, + 547, + 281 + ], + "spans": [ + { + "bbox": [ + 317, + 210, + 547, + 281 + ], + "type": "text", + "content": "- our learned texture manifold enables effective inference-time optimization to texture an object mesh to perceptually match a single real-world RGB image; crucially, we maintain robustness to real-world scenarios of differing views and even geometry with a patch-based perceptual optimization guided by dense correspondences." + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 294, + 392, + 306 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 294, + 392, + 306 + ], + "spans": [ + { + "bbox": [ + 306, + 294, + 392, + 306 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 314, + 547, + 530 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 314, + 547, + 530 + ], + "spans": [ + { + "bbox": [ + 304, + 314, + 547, + 530 + ], + "type": "text", + "content": "Optimization-based Texturing. Various approaches have been proposed to texture 3D shapes by optimizing from aligned image views of the shape. The traditional optimization approach of Zhou et. al. [52] solves a global optimization for a mapping from observed RGB images onto reconstructed geometry. More recently, Huang et. al. [17] introduce a modern adversarial discriminator loss, coupled with differentiable rendering, to optimize for texture on reconstructed geometry to produce realistic texturing robust to camera pose misalignments in real-world RGB-D capture scenarios. PointNeRF [47] and NeuMesh [48] optimize for view-dependent features using distance-based interpolation from the k-nearest neighbor points/vertices; in contrast, we aim to design a method with view-independent texturing that enables robustness to entirely arbitrary viewpoints. While these methods can produce impressive texturing results, they require aligned 2D/3D data and cannot produce textures in unobserved regions." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 546, + 547, + 713 + ], + "type": "text", + "content": "Learned Texture Completion and Generation. Learning-based methods have also explored generative texturing, aiming to learn generalized features for unconditional synthesis or conditional inpainting. Photoshop [34] proposes to learn material retrieval to apply materials to 3D shapes. Recently, several methods have been developed to generate textures on various representations: SPSG [9] produces per-voxel colors with an adversarial differentiable rendering formulation, Pavollo et. al. [35] learn texturing in the UV domain, and Henderson et. al. [15] and Texturify [42] propose to generate per-face mesh colors with variational and adversarial training, respectively. TM-NET [12] is basically the 2D approach for texture generation as it uses unfolded UV maps as the main representation, which is unable to generate" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "8919" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 71, + 361, + 198 + ], + "blocks": [ + { + "bbox": [ + 50, + 71, + 361, + 198 + ], + "lines": [ + { + "bbox": [ + 50, + 71, + 361, + 198 + ], + "spans": [ + { + "bbox": [ + 50, + 71, + 361, + 198 + ], + "type": "image", + "image_path": "b93da614410658cc6da2d5347b5a0be0f60fc03da525c3f744d018db1c5de053.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 206, + 547, + 269 + ], + "lines": [ + { + "bbox": [ + 46, + 206, + 547, + 269 + ], + "spans": [ + { + "bbox": [ + 46, + 206, + 547, + 269 + ], + "type": "text", + "content": "Figure 2: Method overview. Left: we first learn a texture generator for textures represented as a shared local neural field in the barycentric coordinate system of each mesh face. This enables the capture of high-resolution texture detail, while remaining tied to surface geometry, avoiding ambiguities of volumetric field representations. Our learned texture manifold can then be used for texture transfer from a single RGB query image, based on a correspondence-guided patch-based style loss to produce perceptually consistent texturing even for shapes with differing geometry and unknown image pose." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 362, + 72, + 543, + 198 + ], + "blocks": [ + { + "bbox": [ + 362, + 72, + 543, + 198 + ], + "lines": [ + { + "bbox": [ + 362, + 72, + 543, + 198 + ], + "spans": [ + { + "bbox": [ + 362, + 72, + 543, + 198 + ], + "type": "image", + "image_path": "fc629d3f54baabbaa5c6e717438f3d2aae02cc57e8dfed2a00e8d297068382d6.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 298, + 289, + 395 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 298, + 289, + 395 + ], + "spans": [ + { + "bbox": [ + 46, + 298, + 289, + 395 + ], + "type": "text", + "content": "consistent textures near the seams. Moreover, this method uses explicit part information, which significantly simplifies the setup for geometry-aware texture generation. The recent success of neural implicit field representations has also inspired implicit texture field models [32, 3, 11]. Our approach aims to model texture on the surface of a mesh, coupled with the representation capacity of a shared implicit field per mesh face." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 411, + 289, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 411, + 289, + 590 + ], + "spans": [ + { + "bbox": [ + 46, + 411, + 289, + 590 + ], + "type": "text", + "content": "Query-based 3D Understanding. The recent success of vision-language models such as CLIP [36] has sparked interest in query-guided 3D understanding from text and images. Text and image guidance have been exploited for knowledge distillation for 3D semantic understanding [24, 38, 20]. Various shape generation tasks have also been formulated with text queries, by leveraging CLIP as supervision [41, 19, 44]. In particular, Text2Mesh [28] leverages CLIP guidance for text-based texture optimization on 3D shapes. We formulate Mesh2Tex to support image-based queries for texture transfer optimization to various 3D shapes, to reflect potential practical texturing scenarios where images are largely easy to capture or find, with high visual specificity. We thus tackle challenges in geometric and pose misalignments from various potential image queries." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 602, + 104, + 615 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 602, + 104, + 615 + ], + "spans": [ + { + "bbox": [ + 47, + 602, + 104, + 615 + ], + "type": "text", + "content": "3. Method" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 622, + 115, + 634 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 622, + 115, + 634 + ], + "spans": [ + { + "bbox": [ + 47, + 622, + 115, + 634 + ], + "type": "text", + "content": "3.1. Overview" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 641, + 289, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 289, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 289, + 714 + ], + "type": "text", + "content": "We aim to learn a high-quality texture manifold conditioned on a given shape mesh geometry, which supports unconditional texture generation as well as optimization within the texture manifold to fit to image queries for practical texturing scenarios. An overview of our approach is visualized in Figure 2. We propose to learn this texture manifold on a" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 298, + 547, + 418 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 298, + 547, + 418 + ], + "spans": [ + { + "bbox": [ + 304, + 298, + 547, + 418 + ], + "type": "text", + "content": "hybrid representation that combines a mesh representation with a neural field operating on the barycentric coordinates of each mesh face. Our texture generator then generates initial coarse features per-face for a given shape mesh, which are then refined by a shared neural field across the mesh faces. This enables high-resolution texture generation by sampling the neural field on the mesh surface. In the absence of a large-scale dataset of high-quality 3D textured shapes, we supervise the texture generation with an adversarial loss with photorealistic 2D images, through differentiable rendering." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 418, + 548, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 418, + 548, + 552 + ], + "spans": [ + { + "bbox": [ + 304, + 418, + 548, + 552 + ], + "type": "text", + "content": "We can then traverse our learned texture manifold to generate textures for a given shape geometry to perceptually match to image queries. Since an RGB image query may be taken at an arbitrary camera pose, we estimate the object pose in the RGB image along with its normalized object coordinates [45] to guide the texture optimization. Furthermore, we must also support texture transfer scenarios, as having an exact geometric shape match for an arbitrary RGB image query cannot be assumed in practice. We thus employ both a global and local patch-based style loss to generate a realistic texture that perceptually matches the query image." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 561, + 477, + 573 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 561, + 477, + 573 + ], + "spans": [ + { + "bbox": [ + 306, + 561, + 477, + 573 + ], + "type": "text", + "content": "3.2. Mesh-Field Texture Generation" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 580, + 547, + 688 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 580, + 547, + 688 + ], + "spans": [ + { + "bbox": [ + 304, + 580, + 547, + 688 + ], + "type": "text", + "content": "We learn a texture manifold on a mesh-field representation. Given a shape mesh " + }, + { + "bbox": [ + 304, + 580, + 547, + 688 + ], + "type": "inline_equation", + "content": "\\mathcal{M}" + }, + { + "bbox": [ + 304, + 580, + 547, + 688 + ], + "type": "text", + "content": ", we use a latent-variable conditioned encoder-decoder to obtain per-face features " + }, + { + "bbox": [ + 304, + 580, + 547, + 688 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 304, + 580, + 547, + 688 + ], + "type": "text", + "content": ". We then employ a shared neural field " + }, + { + "bbox": [ + 304, + 580, + 547, + 688 + ], + "type": "inline_equation", + "content": "\\psi" + }, + { + "bbox": [ + 304, + 580, + 547, + 688 + ], + "type": "text", + "content": " that operates on each face to produce arbitrary-resolution texturing. High-quality texture generation is then learned by supervision with photorealistic 2D images in an adversarial fashion through differentiable rendering. Our texture generator training is shown in Figure 3." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "type": "text", + "content": "A shape mesh " + }, + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\mathcal{M}" + }, + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "type": "text", + "content": " is represented as a quadrilateral mesh; inspired by the hierarchical mesh representation of Textu" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8920" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "content": "rify [42], we also employ QuadriFlow [18] to parameterize shape meshes as hierarchies of 4-way rotationally symmetric (4-RoSy) fields. We can then leverage convolutional and pooling operators on the neighborhoods of each quad face, enabling encoding and decoding features on such mesh faces with arbitrary topologies. We employ an encoder-decoder face convolutional network " + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "inline_equation", + "content": "G" + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "content": " on " + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "inline_equation", + "content": "\\mathcal{M}" + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "content": ", which takes as input geometric quad face features (per-face normals, fundamental forms, and curvature), and predicts per-face features " + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "inline_equation", + "content": "F_{c}" + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "content": ". Similar to StyleGAN [22] we incorporate a latent texture code " + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 46, + 72, + 289, + 204 + ], + "type": "text", + "content": " into the decoder through a mapping network." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 204, + 288, + 253 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 204, + 288, + 253 + ], + "spans": [ + { + "bbox": [ + 47, + 204, + 288, + 253 + ], + "type": "text", + "content": "As we aim to generate high-quality textures not limited to the mesh face resolution, we leverage a neural field " + }, + { + "bbox": [ + 47, + 204, + 288, + 253 + ], + "type": "inline_equation", + "content": "\\psi" + }, + { + "bbox": [ + 47, + 204, + 288, + 253 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 47, + 204, + 288, + 253 + ], + "type": "inline_equation", + "content": "\\psi" + }, + { + "bbox": [ + 47, + 204, + 288, + 253 + ], + "type": "text", + "content": " takes as input a barycentric coordinate " + }, + { + "bbox": [ + 47, + 204, + 288, + 253 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 47, + 204, + 288, + 253 + ], + "type": "text", + "content": " on a mesh face, along with mean face feature " + }, + { + "bbox": [ + 47, + 204, + 288, + 253 + ], + "type": "inline_equation", + "content": "F_{v}" + }, + { + "bbox": [ + 47, + 204, + 288, + 253 + ], + "type": "text", + "content": " of all incident quad faces:" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 74, + 259, + 288, + 275 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 259, + 288, + 275 + ], + "spans": [ + { + "bbox": [ + 74, + 259, + 288, + 275 + ], + "type": "interline_equation", + "content": "\\psi \\left(p, b _ {1} F _ {v _ {1}} + b _ {2} F _ {v _ {2}} + b _ {3} F _ {v _ {3}}\\right) = c \\in \\mathbf {R} _ {[ - 1, 1 ]} ^ {3}, \\tag {1}", + "image_path": "70afdddad8f779d169913c03c0f5d81373ce3aa37c43fce279530ea00a8cca35.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "inline_equation", + "content": "\\mathcal{A} = \\{v_1, v_2, v_3\\}" + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "text", + "content": " is the triangle half of a quad face " + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "inline_equation", + "content": "\\{v_1, v_2, v_4, v_3\\}" + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "text", + "content": " in which " + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "text", + "content": " lies, " + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "inline_equation", + "content": "\\{b_1, b_2, b_3\\}" + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "text", + "content": " are the barycentric coordinates of " + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "text", + "content": " with respect to triangle " + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "inline_equation", + "content": "\\mathcal{A}" + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "inline_equation", + "content": "c" + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "text", + "content": " is the final output color. We can then generate arbitrary-resolution textures by densely sampling " + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "inline_equation", + "content": "\\psi" + }, + { + "bbox": [ + 47, + 281, + 287, + 342 + ], + "type": "text", + "content": " on each mesh face." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 342, + 289, + 474 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 342, + 289, + 474 + ], + "spans": [ + { + "bbox": [ + 46, + 342, + 289, + 474 + ], + "type": "text", + "content": "To supervise the learning of this mesh-field texture manifold, we differentiably render our generated textures for an adversarial loss with photorealistic 2D images. To render the generated textures, we sample " + }, + { + "bbox": [ + 46, + 342, + 289, + 474 + ], + "type": "inline_equation", + "content": "\\psi" + }, + { + "bbox": [ + 46, + 342, + 289, + 474 + ], + "type": "text", + "content": " at the locations corresponding to each pixel in the rendered view. In addition to implicit field " + }, + { + "bbox": [ + 46, + 342, + 289, + 474 + ], + "type": "inline_equation", + "content": "\\psi" + }, + { + "bbox": [ + 46, + 342, + 289, + 474 + ], + "type": "text", + "content": " rendering, we also pass the output feature map " + }, + { + "bbox": [ + 46, + 342, + 289, + 474 + ], + "type": "inline_equation", + "content": "F_{c}" + }, + { + "bbox": [ + 46, + 342, + 289, + 474 + ], + "type": "text", + "content": " into one convolutional layer and render it using PyTorch3D [37] differentiable renderer and supervise it similarly as a proxy loss. We then train the texture manifold in an end-to-end fashion using a non-saturating GAN loss with gradient penalty and path length regularization." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 473, + 288, + 510 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 473, + 288, + 510 + ], + "spans": [ + { + "bbox": [ + 46, + 473, + 288, + 510 + ], + "type": "text", + "content": "During training, we do not use any paired geometry with rendered images and only use unpaired collections of real-world images and synthetic shapes." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 515, + 247, + 529 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 515, + 247, + 529 + ], + "spans": [ + { + "bbox": [ + 47, + 515, + 247, + 529 + ], + "type": "text", + "content": "3.3. Texture Transfer from a Single Image" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 534, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 534, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 534, + 289, + 715 + ], + "type": "text", + "content": "Once learned, we can not only use our texture manifold for unconditional generation, but also importantly traverse through the manifold to produce shape texturing that matches to a query RGB image " + }, + { + "bbox": [ + 46, + 534, + 289, + 715 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 534, + 289, + 715 + ], + "type": "text", + "content": ". This represents real-world texturing scenarios where a user may wish to texture a shape based on an easy-to-capture image inspiration. Here, notable challenges are lack of knowledge of the ground truth object pose in " + }, + { + "bbox": [ + 46, + 534, + 289, + 715 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 534, + 289, + 715 + ], + "type": "text", + "content": ", and handling inexact geometric matches between the shape mesh to be textured and the object in " + }, + { + "bbox": [ + 46, + 534, + 289, + 715 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 534, + 289, + 715 + ], + "type": "text", + "content": " – as it is not practical, nor always desirable, to assume the ability to reconstruct or retrieve the exact geometry of the object in an arbitrary image. We thus aim to produce textures on a shape to perceptually match an image " + }, + { + "bbox": [ + 46, + 534, + 289, + 715 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 534, + 289, + 715 + ], + "type": "text", + "content": " in these challenging scenarios. Our texture transfer optimization is illustrated in Figure 4." + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 310, + 71, + 545, + 160 + ], + "blocks": [ + { + "bbox": [ + 310, + 71, + 545, + 160 + ], + "lines": [ + { + "bbox": [ + 310, + 71, + 545, + 160 + ], + "spans": [ + { + "bbox": [ + 310, + 71, + 545, + 160 + ], + "type": "image", + "image_path": "0cd58eb7be127c44c750ee16710cbda8e5757cf3a38a92b7c351d95d351b67b5.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "lines": [ + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "spans": [ + { + "bbox": [ + 304, + 170, + 547, + 266 + ], + "type": "text", + "content": "Figure 3: Mesh-field texture generation. We employ face convolutions following [42] for initial coarse feature generation, followed by a neural field that interprets the per-face features to produce refined color outputs at arbitrary locations on the mesh surface. The hybrid mesh-field texture generation is supervised in an adversarial fashion through differentiable rendering, with photorealistic 2D images representing the real distribution." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 312, + 289, + 541, + 384 + ], + "blocks": [ + { + "bbox": [ + 312, + 289, + 541, + 384 + ], + "lines": [ + { + "bbox": [ + 312, + 289, + 541, + 384 + ], + "spans": [ + { + "bbox": [ + 312, + 289, + 541, + 384 + ], + "type": "image", + "image_path": "cdb58652f794816070dfb59a6ac4423cd845e7b93cb106b671583cecbdcdcc21.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 392, + 547, + 501 + ], + "lines": [ + { + "bbox": [ + 304, + 392, + 547, + 501 + ], + "spans": [ + { + "bbox": [ + 304, + 392, + 547, + 501 + ], + "type": "text", + "content": "Figure 4: Texture transfer optimization from a single image. We traverse our learned texture manifold for texture transfer from a single RGB image query. Since image alignment may be unknown, we estimate a coarse pose along with finer-grained dense NOC correspondences. We leverage the NOCs to guide patch sampling for our patch-based style loss to produce texturing that perceptually matches to the query images, without requiring any exact geometric shape matches to the image." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "text", + "content": "From " + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "text", + "content": ", we first estimate the object pose as the azimuth and elevation angles, " + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "inline_equation", + "content": "\\alpha^a" + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "inline_equation", + "content": "\\alpha^e" + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "text", + "content": ", respectively. To this end, we use a ResNet-18 [14] network on " + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "text", + "content": ", pre-trained on synthetic rendered shapes to classify " + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "inline_equation", + "content": "\\alpha^a" + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "inline_equation", + "content": "\\alpha^e" + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "text", + "content": " into 12 and 5 bins for a coarse rotation estimate. For finer-grained reasoning, we predict normalized object coordinates [45] " + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "inline_equation", + "content": "I_{\\mathrm{NOC}}" + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "text", + "content": ", dense correspondences from the object pixels in " + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 304, + 533, + 547, + 653 + ], + "type": "text", + "content": " to the canonical space of the object. For NOC prediction, we use a UNet-style network with an EfficientNet-b4 [43] backbone, trained on synthetic rendered shape data." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": "We then formulate our texture transfer optimization. We differentiably render our generated texture from initial pose estimate " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\alpha^a" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\alpha^e" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": " to produce the rendered image produced from local neural field " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\psi X" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": ". Since we optimize for perceptual similarity, we employ a style loss [13] in a global and" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 314, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 758 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 758 + ], + "type": "text", + "content": "8921" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 188, + 83 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 188, + 83 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 188, + 83 + ], + "type": "text", + "content": "local fashion to compare " + }, + { + "bbox": [ + 47, + 72, + 188, + 83 + ], + "type": "inline_equation", + "content": "X" + }, + { + "bbox": [ + 47, + 72, + 188, + 83 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 72, + 188, + 83 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 47, + 72, + 188, + 83 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 59, + 84, + 286, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 84, + 286, + 96 + ], + "spans": [ + { + "bbox": [ + 59, + 84, + 286, + 96 + ], + "type": "text", + "content": "We then optimize for latent texture code " + }, + { + "bbox": [ + 59, + 84, + 286, + 96 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 59, + 84, + 286, + 96 + ], + "type": "text", + "content": " with the loss:" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 102, + 287, + 184 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 102, + 287, + 184 + ], + "spans": [ + { + "bbox": [ + 47, + 102, + 287, + 184 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} L = w _ {g l o b} \\sum_ {h = 1} ^ {N _ {h}} \\sum_ {l = 1} ^ {N _ {l}} L _ {g l o b} \\left(I ^ {h, l}, X ^ {h, l}\\right) \\\\ + w _ {p a t c h} \\sum_ {p = 1} ^ {N _ {p}} \\sum_ {h = 1} ^ {N _ {h}} \\sum_ {l = 1} ^ {N _ {l}} L _ {p a t c h} \\left(I _ {p} ^ {h, l} (x, y), X _ {p} ^ {h, l} \\left(x ^ {\\prime}, y ^ {\\prime}\\right)\\right), \\tag {2} \\\\ \\end{array}", + "image_path": "2ac09d99f0cf4b0d8247959a4a5006199828c0e1c8c9c58fa80093cdc75f90a2.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 190, + 288, + 226 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 190, + 288, + 226 + ], + "spans": [ + { + "bbox": [ + 46, + 190, + 288, + 226 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 190, + 288, + 226 + ], + "type": "inline_equation", + "content": "L_{glob}" + }, + { + "bbox": [ + 46, + 190, + 288, + 226 + ], + "type": "text", + "content": " denotes a global style loss, " + }, + { + "bbox": [ + 46, + 190, + 288, + 226 + ], + "type": "inline_equation", + "content": "L_{patch}" + }, + { + "bbox": [ + 46, + 190, + 288, + 226 + ], + "type": "text", + "content": " a local patch-based style loss, and " + }, + { + "bbox": [ + 46, + 190, + 288, + 226 + ], + "type": "inline_equation", + "content": "w_{glob}" + }, + { + "bbox": [ + 46, + 190, + 288, + 226 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 190, + 288, + 226 + ], + "type": "inline_equation", + "content": "w_{patch}" + }, + { + "bbox": [ + 46, + 190, + 288, + 226 + ], + "type": "text", + "content": " constants to balance the loss values." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "spans": [ + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": "Global style loss. " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "L_{glob}" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": " considers the full images " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "X" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": " at " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "N_h = 3" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": " resolution levels (original, half, and quarter resolution): " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "I^h" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "X^h" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "h \\in [1,2,3]" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": ". The global style loss is then computed on each pair " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "(X^h, I^h)" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": " on " + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "inline_equation", + "content": "N_l = 5" + }, + { + "bbox": [ + 46, + 240, + 287, + 300 + ], + "type": "text", + "content": " VGG feature layers." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "spans": [ + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": "Patch style losses. Since the precise structure of the object in " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " may not match with that of " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "X" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " (e.g. geometry mismatch or inconsistent pose prediction), we further employ local style losses on image patches. We extract " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "N_{p} = 2" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " patches " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "I_{p}(x,y)" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " randomly per iteration, located at patch centers " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "(x,y)" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " within the object. We then use the corresponding NOC estimate at the patch location, " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "I_{\\mathrm{NOC}}(x,y)" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": ", and find a corresponding patch " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "X_{p}(x^{\\prime},y^{\\prime})" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "(x^{\\prime},y^{\\prime})" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " is the pixel location whose shape NOC is closest to " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "I_{\\mathrm{NOC}}(x,y)" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " w.r.t. " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "\\ell_2" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " distance. Note that since " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "X" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " has been rendered from a shape mesh, we can use ground truth shape NOCs for " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "X" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": ", and only require predicted NOCs for " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": ". This provides a coarse correspondence between patches to guide the style loss. Similar to " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "L_{glob}" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": ", we apply " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "L_{patch}" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " at " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "N_{h} = 3" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " resolution levels and with " + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "inline_equation", + "content": "N_{l} = 5" + }, + { + "bbox": [ + 46, + 315, + 288, + 494 + ], + "type": "text", + "content": " VGG feature layers." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 508, + 287, + 580 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 508, + 287, + 580 + ], + "spans": [ + { + "bbox": [ + 46, + 508, + 287, + 580 + ], + "type": "text", + "content": "Face feature refinement. With texture code " + }, + { + "bbox": [ + 46, + 508, + 287, + 580 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 46, + 508, + 287, + 580 + ], + "type": "text", + "content": " optimized from Equation 2, we further allow for texture refinement by unfreezing the last two face convolutional layers in the texture generator. We optimize for refined weights in the surface features using only " + }, + { + "bbox": [ + 46, + 508, + 287, + 580 + ], + "type": "inline_equation", + "content": "L_{patch}" + }, + { + "bbox": [ + 46, + 508, + 287, + 580 + ], + "type": "text", + "content": ", which enables better capturing of local detail in " + }, + { + "bbox": [ + 46, + 508, + 287, + 580 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 508, + 287, + 580 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 594, + 287, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 287, + 665 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 287, + 665 + ], + "type": "text", + "content": "Implementation Details Our Mesh2Tex model is implemented using PyTorch and trained using an Adam [23] optimizer with learning rates of 1e-4, 12e-4, 1e-4, 14e-4 for the encoder, generator, neural field " + }, + { + "bbox": [ + 46, + 594, + 287, + 665 + ], + "type": "inline_equation", + "content": "\\psi" + }, + { + "bbox": [ + 46, + 594, + 287, + 665 + ], + "type": "text", + "content": " parameters and both discriminators, respectively. Mesh2Tex is trained on 2 NVIDIA A6000s for 50k iterations (" + }, + { + "bbox": [ + 46, + 594, + 287, + 665 + ], + "type": "inline_equation", + "content": "\\sim" + }, + { + "bbox": [ + 46, + 594, + 287, + 665 + ], + "type": "text", + "content": " 100 hours) until convergence." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 665, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 286, + 713 + ], + "type": "text", + "content": "At test-time, we optimize latent codes for 100 iterations and refined weights for additional 300 iterations, which takes " + }, + { + "bbox": [ + 46, + 665, + 286, + 713 + ], + "type": "inline_equation", + "content": "\\sim 400" + }, + { + "bbox": [ + 46, + 665, + 286, + 713 + ], + "type": "text", + "content": "s in total. During texture optimization, we extract " + }, + { + "bbox": [ + 46, + 665, + 286, + 713 + ], + "type": "inline_equation", + "content": "64 \\times 64" + }, + { + "bbox": [ + 46, + 665, + 286, + 713 + ], + "type": "text", + "content": " patches. We provide further details in the supplemental." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 72, + 359, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 359, + 83 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 359, + 83 + ], + "type": "text", + "content": "4. Results" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 92, + 547, + 141 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 92, + 547, + 141 + ], + "spans": [ + { + "bbox": [ + 305, + 92, + 547, + 141 + ], + "type": "text", + "content": "We evaluate the texture generation capabilities of Mesh2Tex on unconditional generation and image-based texture generation, on both synthetic and real data. For both scenarios, our texture generation is trained from real images." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 163, + 547, + 331 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 163, + 547, + 331 + ], + "spans": [ + { + "bbox": [ + 304, + 163, + 547, + 331 + ], + "type": "text", + "content": "Datasets. For evaluation, we use object geometry from ShapeNet [4] for texturing, and real-world query images from ScanNet [8] for chairs, and from CompCars [49] for cars. For synthetic experiments requiring exact geometric matches, we use ShapeNet textured objects and render query image views. For real image queries with close matching geometry, we use Scan2CAD [1] annotations for chair meshes to ScanNet images. For CompCars, we use the coarse pose information (front, back, left, right, etc.) to estimate close image alignments. During training, poses are rendered to coarsely approximate the distribution of real train images (e.g., for cars, 8 poses representing front, back, left, right, front-left, front-right, back-left, and back-right; for chairs, random poses from PhotoShape pose estimates)." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 332, + 547, + 404 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 332, + 547, + 404 + ], + "spans": [ + { + "bbox": [ + 304, + 332, + 547, + 404 + ], + "type": "text", + "content": "Note that all methods, except GET3D, were trained with the same set of ShapeNet meshes, and images from PhotoShape [34] and CompCars [49] for chairs and cars. GET3D requires a much denser sampling of images per shape rather than a single view per shape, so we instead compare with the authors' released pre-trained GET3D model." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 427, + 547, + 608 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 427, + 547, + 608 + ], + "spans": [ + { + "bbox": [ + 304, + 427, + 547, + 608 + ], + "type": "text", + "content": "Evaluation metrics. We evaluate the perceptual quality of our generated textures with several metrics. To measure the realistic quality of the textures, we compare rendered views of generated textures on various shapes to real-world images, using the standard FID [16] and KID [2] scores used for assessing generated image quality. For FID and KID evaluation, we use real images from PhotoShape [34] and CompCars [49] for chairs and cars, respectively, and 6 rendered views from each synthesized textured shape. Additionally, for texture transfer from a single image, we compute CLIP [36] similarity as cosine distances between the query image and rendered texture. In synthetic experiment setups where exact geometric matches are available, we further compute an LPIPS [51] perceptual metric between synthesized views and the query image." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 629, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 547, + 713 + ], + "type": "text", + "content": "Baselines. We compare with several state-of-the-art texturing methods leveraging various texture representations: Yu et. al. [50] learns texture generation on a UV map parameterization, EG3D [3] leverages an efficient triplane representation for view synthesis, Texturify [42] generates per-face colors on a mesh, and GET3D [11] jointly estimates color and geometry with triplane representations." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8922" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 51, + 70, + 286, + 299 + ], + "blocks": [ + { + "bbox": [ + 51, + 70, + 286, + 299 + ], + "lines": [ + { + "bbox": [ + 51, + 70, + 286, + 299 + ], + "spans": [ + { + "bbox": [ + 51, + 70, + 286, + 299 + ], + "type": "image", + "image_path": "d0013ebdc1f5400695e82c1fbd471b2120309b1ad95a9ff4add7b59ca0ca4734.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 307, + 288, + 343 + ], + "lines": [ + { + "bbox": [ + 46, + 307, + 288, + 343 + ], + "spans": [ + { + "bbox": [ + 46, + 307, + 288, + 343 + ], + "type": "text", + "content": "Figure 5: Unconditional texturing for meshes from ShapeNet [4], in comparison with state of the art. Our approach generates more realistic, detailed textures." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 50, + 366, + 287, + 441 + ], + "blocks": [ + { + "bbox": [ + 50, + 366, + 287, + 441 + ], + "lines": [ + { + "bbox": [ + 50, + 366, + 287, + 441 + ], + "spans": [ + { + "bbox": [ + 50, + 366, + 287, + 441 + ], + "type": "table", + "html": "
MethodParameterizationChairsCars
FIDKIDFIDKID
EG3DTri-plane Implicit36.452.1583.115.95
Yu et al.UV38.982.4673.635.77
GET3DTri-plane Implicit46.203.0289.626.92
Texturify4-RoSy Field31.081.7559.554.97
Ours4-RoSy Implicit Field30.011.6941.353.41
", + "image_path": "deb893a413c8a32d831fd5afc74de7c146d8e7e7d1d783ec716e42f2005a9c49.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 449, + 288, + 486 + ], + "lines": [ + { + "bbox": [ + 46, + 449, + 288, + 486 + ], + "spans": [ + { + "bbox": [ + 46, + 449, + 288, + 486 + ], + "type": "text", + "content": "Table 1: Unconditional texture generation for 3D shapes. Our mesh-field approach outperforms state of the art in generation quality. The KID values are scaled by " + }, + { + "bbox": [ + 46, + 449, + 288, + 486 + ], + "type": "inline_equation", + "content": "10^{2}" + }, + { + "bbox": [ + 46, + 449, + 288, + 486 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 47, + 508, + 231, + 521 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 508, + 231, + 521 + ], + "spans": [ + { + "bbox": [ + 47, + 508, + 231, + 521 + ], + "type": "text", + "content": "4.1. Unconditional Texture Generation" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 528, + 288, + 588 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 528, + 288, + 588 + ], + "spans": [ + { + "bbox": [ + 46, + 528, + 288, + 588 + ], + "type": "text", + "content": "Table 1 and Figure 5 show quantitative and qualitative comparisons of unconditional texture generation to state of the art. Our hybrid mesh-field texture representation enables richer texture generation with finer-scale details than state-of-the-art baselines." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 597, + 247, + 612 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 597, + 247, + 612 + ], + "spans": [ + { + "bbox": [ + 47, + 597, + 247, + 612 + ], + "type": "text", + "content": "4.2. Texture Transfer from a Single Image" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 618, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 618, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 618, + 288, + 715 + ], + "type": "text", + "content": "We further evaluate texturing of objects from image queries, which opens up new possibilities in the content creation process. We consider both synthetic image queries, which enable texturing of exact geometric matches, as well as real image queries, where no object geometry matches exactly to the queries. For all baselines, we apply a similar texture optimization as our approach, leveraging global and patch-style losses without NOC guidance. During test-time" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 310, + 71, + 544, + 327 + ], + "blocks": [ + { + "bbox": [ + 310, + 71, + 544, + 327 + ], + "lines": [ + { + "bbox": [ + 310, + 71, + 544, + 327 + ], + "spans": [ + { + "bbox": [ + 310, + 71, + 544, + 327 + ], + "type": "image", + "image_path": "7ddc1782154188f13c5cfd1743876dc8807d6cb5722cfc53f469bc9e940a71a3.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 335, + 548, + 407 + ], + "lines": [ + { + "bbox": [ + 304, + 335, + 548, + 407 + ], + "spans": [ + { + "bbox": [ + 304, + 335, + 548, + 407 + ], + "type": "text", + "content": "Figure 6: Texture transfer from synthetic image queries to exact shape geometry with unknown image alignment. Mesh2Tex produces more geometrically consistent texturing with finer-resolution details captured in our mesh-field texture representation. Note that GET3D models both geometry and color, resulting in possible geometric changes." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 437, + 547, + 486 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 437, + 547, + 486 + ], + "spans": [ + { + "bbox": [ + 304, + 437, + 547, + 486 + ], + "type": "text", + "content": "optimization in texture transfer experiments, we consider settings of known/unknown shape and pose for image queries, but we use the same adversarially trained model for all test-time experiments." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 500, + 495, + 513 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 500, + 495, + 513 + ], + "spans": [ + { + "bbox": [ + 306, + 500, + 495, + 513 + ], + "type": "text", + "content": "4.2.1 Synthetic Image Query Experiments" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 519, + 547, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 519, + 547, + 616 + ], + "spans": [ + { + "bbox": [ + 304, + 519, + 547, + 616 + ], + "type": "text", + "content": "Exact geometry and known image alignment. We evaluate texture generation from a single image query to exactly matching object geometry with known image alignment in Tables 2 and 3, which measure the distribution quality and perceptual match to the query image, respectively. The optimization through our high-fidelity texture manifold enables more detailed texturing to match to various texture changes in the query image, in comparison to baselines." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 547, + 715 + ], + "type": "text", + "content": "Exact geometry and unknown image alignment. We evaluate texture generation from a single image query where the pose of the shape in the input query is unknown. Quantitative evaluation with state of the art is shown in Tables 4 and 5, which measure the distribution quality and perceptual match to the query image, respectively. Figure 6 visualizes qualitative comparisons. For GET3D, we do not evaluate" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8923" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 59, + 71, + 276, + 339 + ], + "blocks": [ + { + "bbox": [ + 59, + 71, + 276, + 339 + ], + "lines": [ + { + "bbox": [ + 59, + 71, + 276, + 339 + ], + "spans": [ + { + "bbox": [ + 59, + 71, + 276, + 339 + ], + "type": "image", + "image_path": "549825ed01b8ce553467c83e10f6b6ebca9bd4009b0a44d3ede2f320263d4303.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 348, + 288, + 396 + ], + "lines": [ + { + "bbox": [ + 46, + 348, + 288, + 396 + ], + "spans": [ + { + "bbox": [ + 46, + 348, + 288, + 396 + ], + "type": "text", + "content": "Figure 7: Texture transfer from real images (ScanNet) to closely matching shape geometry (ShapeNet). Despite inexact geometry and pose, Mesh2Tex produces perceptually consistent texturing." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 426, + 287, + 451 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 426, + 287, + 451 + ], + "spans": [ + { + "bbox": [ + 46, + 426, + 287, + 451 + ], + "type": "text", + "content": "LPIPS, as it can produce geometric changes resulting in an inexact geometry match to the query." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 451, + 287, + 511 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 451, + 287, + 511 + ], + "spans": [ + { + "bbox": [ + 46, + 451, + 287, + 511 + ], + "type": "text", + "content": "Even with exact geometry, the unknown image alignment poses a notable challenge, resulting in degraded performance in the baselines. Our approach maintains more robustness due to the NOC guidance in our patch loss during texture optimization, producing more plausible texture generation." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 525, + 287, + 632 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 525, + 287, + 632 + ], + "spans": [ + { + "bbox": [ + 46, + 525, + 287, + 632 + ], + "type": "text", + "content": "Texture transfer. We evaluate texture transfer experiments from a single image query to an arbitrary shape of a different geometry than the input query. Tables 6 and 7 compare our approach to state of the art. This challenging scenario of differing geometry results in a performance drop in all methods; however, due to our NOC-guided style optimization on a mesh-field texture representation, Mesh2Tex can produce textures on novel shape geometry with greater coherency and finer details than baselines." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 647, + 216, + 659 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 647, + 216, + 659 + ], + "spans": [ + { + "bbox": [ + 47, + 647, + 216, + 659 + ], + "type": "text", + "content": "4.2.2 Real Image Query Experiments" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 287, + 713 + ], + "type": "text", + "content": "Closely-matching geometry and image alignment. We evaluate texturing from a single real-world image, where the shape geometry to be textured and image alignment are close (as we cannot guarantee an exact match to real-world" + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 309, + 70, + 545, + 171 + ], + "blocks": [ + { + "bbox": [ + 309, + 70, + 545, + 171 + ], + "lines": [ + { + "bbox": [ + 309, + 70, + 545, + 171 + ], + "spans": [ + { + "bbox": [ + 309, + 70, + 545, + 171 + ], + "type": "table", + "html": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
FIDKIDFIDKIDFIDKID
EG3D146.69.49297.920.82318.827.39
Yu et al.153.110.2289.418.88329.828.60
GET3D265.626.67248.815.57336.538.74
Texturify155.910.94301.420.63342.233.65
Ours115.45.38165.56.84309.726.50
", + "image_path": "919d674751877b92c8c90b9692ffcf07a0ad547046ec1816834f0e632385e1ba.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 179, + 547, + 240 + ], + "lines": [ + { + "bbox": [ + 304, + 179, + 547, + 240 + ], + "spans": [ + { + "bbox": [ + 304, + 179, + 547, + 240 + ], + "type": "text", + "content": "Table 2: Evaluation on aligned queried texture generation with image queries from rendered ShapeNet chairs and cars, as well as real-world images from ScanNet chairs. Mesh2Tex generates more realistic textures from single-image queries. The KID values are scaled by " + }, + { + "bbox": [ + 304, + 179, + 547, + 240 + ], + "type": "inline_equation", + "content": "10^{2}" + }, + { + "bbox": [ + 304, + 179, + 547, + 240 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 260, + 545, + 369 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 260, + 545, + 369 + ], + "spans": [ + { + "bbox": [ + 304, + 260, + 545, + 369 + ], + "type": "text", + "content": "images). We compare with state of the art in Tables 2 and 3. In the real-world setting, view-dependent effects in real images (e.g., specular highlights, reflections) pose a notable challenge in evaluating texture optimization. With close but inexact geometry and alignment, our method can still produce textures that are consistent with the image queries due to NOC-guided optimization, while baseline methods struggle to transfer textures from incomplete and cluttered real-world objects." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 384, + 547, + 468 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 384, + 547, + 468 + ], + "spans": [ + { + "bbox": [ + 304, + 384, + 547, + 468 + ], + "type": "text", + "content": "Closely-matching geometry and unknown image alignment. We further consider texturing from a single real-world image to close shape geometry with unknown image alignment. We show qualitative results in Figure 7 and quantitative evaluation in Tables 4 and 5. Our NOC-guided optimization through our texture manifold generates more perceptually representative textures." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 483, + 547, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 483, + 547, + 602 + ], + "spans": [ + { + "bbox": [ + 304, + 483, + 547, + 602 + ], + "type": "text", + "content": "Texture transfer. Finally, we evaluate the challenging texture transfer scenario from a single real-world image from ScanNet [8] to an arbitrary ShapeNet [4] mesh of the same class category. This reflects potential texturing applications from users who wish to use an inspirational image to generate texturing on a given shape. We show a quantitative comparison in Tables 6 and 7, and qualitative results in Figure 8. Our mesh-field texture representation maintains more detail with NOC-guided patch loss to provide more robustness during optimization." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 603, + 545, + 663 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 603, + 545, + 663 + ], + "spans": [ + { + "bbox": [ + 304, + 603, + 545, + 663 + ], + "type": "text", + "content": "Generated textures may differ from input images in Figs. 7 and 8 since shape geometry and poses differ between the shape to be textured and the query image. Thus, we cannot leverage any 1-1 correspondences, instead optimizing for patch-based perceptual similarity." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 670, + 450, + 684 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 670, + 450, + 684 + ], + "spans": [ + { + "bbox": [ + 306, + 670, + 450, + 684 + ], + "type": "text", + "content": "4.3. Applicability to real scans" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 689, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 689, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 306, + 689, + 545, + 715 + ], + "type": "text", + "content": "Our method can also be easily applied to real scanned shapes, by applying QuadriFlow [18] to convert Marching" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8924" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 70, + 287, + 322 + ], + "blocks": [ + { + "bbox": [ + 49, + 70, + 287, + 322 + ], + "lines": [ + { + "bbox": [ + 49, + 70, + 287, + 322 + ], + "spans": [ + { + "bbox": [ + 49, + 70, + 287, + 322 + ], + "type": "image", + "image_path": "92bdb086cc612d4c851b461e1dda894964d6d3659ac19a99f642b550f2f53807.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 330, + 289, + 392 + ], + "lines": [ + { + "bbox": [ + 46, + 330, + 289, + 392 + ], + "spans": [ + { + "bbox": [ + 46, + 330, + 289, + 392 + ], + "type": "text", + "content": "Figure 8: Texture transfer from real images (ScanNet, CompCars) to arbitrary shape geometry of the same class category (ShapeNet). Under this challenging scenario, our NOC-guided patch optimization enables plausible texturing for image queries." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 56, + 415, + 277, + 485 + ], + "blocks": [ + { + "bbox": [ + 56, + 415, + 277, + 485 + ], + "lines": [ + { + "bbox": [ + 56, + 415, + 277, + 485 + ], + "spans": [ + { + "bbox": [ + 56, + 415, + 277, + 485 + ], + "type": "image", + "image_path": "4079c15c8602aea0b5d9034c78b98d4376cd101d065ee7bd017c98a40ebdb1d4.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 495, + 288, + 533 + ], + "lines": [ + { + "bbox": [ + 46, + 495, + 288, + 533 + ], + "spans": [ + { + "bbox": [ + 46, + 495, + 288, + 533 + ], + "type": "text", + "content": "Figure 9: Texturing on real scanned objects from Redwood dataset. Mesh2Tex is able to generate consistent textures for non-synthetic geometry without finetuning." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 564, + 288, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 564, + 288, + 601 + ], + "spans": [ + { + "bbox": [ + 46, + 564, + 288, + 601 + ], + "type": "text", + "content": "Cubes meshes to a quad mesh input. Fig. 9 shows our texturing of scanned shapes from the Redwood [6] dataset based on real ScanNet image queries." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 610, + 116, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 610, + 116, + 623 + ], + "spans": [ + { + "bbox": [ + 47, + 610, + 116, + 623 + ], + "type": "text", + "content": "4.4. Ablations" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "content": "What is the impact of our mesh-field representation for texture generation? Texturify [42] represents a per-face mesh color generation approach and the texturing results in coarse alignment of geometry and color features, while we introduce a shared barycentric neural field to capture high-fidelity details. Figure 5 shows our much finer-level detail generation, particularly for complex textures on cars." + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 309, + 70, + 547, + 169 + ], + "blocks": [ + { + "bbox": [ + 309, + 70, + 547, + 169 + ], + "lines": [ + { + "bbox": [ + 309, + 70, + 547, + 169 + ], + "spans": [ + { + "bbox": [ + 309, + 70, + 547, + 169 + ], + "type": "table", + "html": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
CLIPLPIPSCLIPLPIPSCLIP
EG3D89.8716.4183.2715.6982.86
Yu et al.89.7316.2684.3314.8382.93
GET3D85.00-81.38-78.52
Texturify89.2216.2383.8214.6981.71
Ours92.2714.6485.9114.7784.28
", + "image_path": "57a2707f49b66021e29bbca880447b75f69c2abd6d9d146726a6389a2f1d217c.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 176, + 547, + 237 + ], + "lines": [ + { + "bbox": [ + 304, + 176, + 547, + 237 + ], + "spans": [ + { + "bbox": [ + 304, + 176, + 547, + 237 + ], + "type": "text", + "content": "Table 3: Evaluation on aligned queried texture generation with image queries from rendered ShapeNet chairs and cars, as well as real-world images from ScanNet chairs. Our texture transfer optimization produces more perceptually representative texturing results." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 259, + 547, + 391 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 259, + 547, + 391 + ], + "spans": [ + { + "bbox": [ + 304, + 259, + 547, + 391 + ], + "type": "text", + "content": "What is the impact of patch style loss in the texture optimization process? Table 8 shows that our patch-based style loss significantly improves texture transfer optimization performance, allowing for the capture of more local detail and robustness to mismatches to the query image. The patch-based optimization enables better capture of texture differences in shape parts than when only using the whole image. Namely, ablating patch style loss results in texture leaks between parts of different colors, an inability to capture textures of fine structures such as thin chair legs, and artifacts around texture-background borders." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 392, + 547, + 475 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 392, + 547, + 475 + ], + "spans": [ + { + "bbox": [ + 304, + 392, + 547, + 475 + ], + "type": "text", + "content": "What is the impact of NOC guidance for the patch style loss? In Table 8, we see that the NOC guidance helps to improve the perceptual quality of results by establishing coarse correspondence to the query image. The NOC guidance largely affects local texture changes inherent to small-scale and thin parts (e.g., chair arms, legs), while only global style is captured without NOCs." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 476, + 547, + 560 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 476, + 547, + 560 + ], + "spans": [ + { + "bbox": [ + 304, + 476, + 547, + 560 + ], + "type": "text", + "content": "What is the effect of surface feature optimization? Following latent texture code optimization, we allow for surface features in the texture generator to further be optimized, which produces slightly improved local texture detail, as shown in Table 8. Optimizing for surface features allows for non-harmful and small extending the flexibility of texture generation to better express high-contrast textures." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 561, + 545, + 609 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 561, + 545, + 609 + ], + "spans": [ + { + "bbox": [ + 304, + 561, + 545, + 609 + ], + "type": "text", + "content": "What is the effect of global style loss? Table 8 shows that without our global style loss, the consistency of texture transfer is severely reduced. The single patch-based style loss enhances similarity to queries locally, but not globally." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 610, + 547, + 657 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 610, + 547, + 657 + ], + "spans": [ + { + "bbox": [ + 304, + 610, + 547, + 657 + ], + "type": "text", + "content": "Following latent texture code optimization, we allow for surface features in the texture generator to further be optimized, which produces slightly improved local texture detail, as shown in Table 8." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 658, + 547, + 671 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 658, + 547, + 671 + ], + "spans": [ + { + "bbox": [ + 306, + 658, + 547, + 671 + ], + "type": "text", + "content": "We refer to the supplemental for qualitative ablation analysis." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 689, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 547, + 715 + ], + "type": "text", + "content": "Limitations. Mesh2Tex offers a promising step towards conditional mesh texturing from a single image, though vari-" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8925" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 70, + 286, + 171 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 286, + 171 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 286, + 171 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 286, + 171 + ], + "type": "table", + "html": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
FIDKIDFIDKIDFIDKID
EG3D155.29.13326.824.48319.427.18
Yu et al.160.09.88343.332.71327.128.20
GET3D271.926.54254.416.63337.338.76
Texturify174.211.74344.225.34333.328.81
Ours121.15.08165.86.77311.926.73
", + "image_path": "8cb32d160a0199ec0e9bd4ec36cd4d14589313af81596b510e7ae84f362d7576.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 50, + 263, + 286, + 360 + ], + "blocks": [ + { + "bbox": [ + 46, + 178, + 288, + 240 + ], + "lines": [ + { + "bbox": [ + 46, + 178, + 288, + 240 + ], + "spans": [ + { + "bbox": [ + 46, + 178, + 288, + 240 + ], + "type": "text", + "content": "Table 4: Evaluation on unaligned queried texture generation with image queries from rendered ShapeNet chairs and cars, as well as real images from ScanNet chairs. Mesh2Tex maintains more realistic texture details than state of the art. The KID values are scaled by " + }, + { + "bbox": [ + 46, + 178, + 288, + 240 + ], + "type": "inline_equation", + "content": "10^{2}" + }, + { + "bbox": [ + 46, + 178, + 288, + 240 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 263, + 286, + 360 + ], + "lines": [ + { + "bbox": [ + 50, + 263, + 286, + 360 + ], + "spans": [ + { + "bbox": [ + 50, + 263, + 286, + 360 + ], + "type": "table", + "html": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNet
Exact geometryClose geometry
CLIPLPIPSCLIPLPIPSCLIP
EG3D89.5116.8381.9316.1483.40
Yu et al.88.9816.8179.3521.8482.67
GET3D84.66-81.54-79.02
Texturify88.2416.8280.4515.4282.26
Ours91.5714.9685.4214.9784.28
", + "image_path": "9e024271612caed987465241e9a4fcddfa5cf20c0bfc62920729864d19244d4b.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 50, + 453, + 286, + 526 + ], + "blocks": [ + { + "bbox": [ + 46, + 369, + 288, + 431 + ], + "lines": [ + { + "bbox": [ + 46, + 369, + 288, + 431 + ], + "spans": [ + { + "bbox": [ + 46, + 369, + 288, + 431 + ], + "type": "text", + "content": "Table 5: Evaluation on unaligned queried texture generation to ShapeNet chairs and cars from rendered ShapeNet objects as well as real-world image queries from ScanNet chairs. Our NOC-guided patch style loss maintains more robustness to the unknown image alignment." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 453, + 286, + 526 + ], + "lines": [ + { + "bbox": [ + 50, + 453, + 286, + 526 + ], + "spans": [ + { + "bbox": [ + 50, + 453, + 286, + 526 + ], + "type": "table", + "html": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNetCars CompCars
FIDKIDFIDKIDFIDKIDFIDKID
EG3D297.428.53343.626.57355.233.31352.339.15
Yu et al.303.429.10351.126.75362.634.20385.451.37
GET3D--------
Texturify307.929.63357.127.05370.434.85264.729.23
Ours276.726.17194.510.11348.532.33203.721.48
", + "image_path": "b10bc9aa0aad8f420ab8757700e813acae49c7f4564ad3b3dd63c8991d8d271c.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "text", + "content": "ous limitations remain. For instance, our approach does not explicitly model semantics, potentially leading to distortions in texture in semantically meaningful areas (e.g., spokes of a car wheel). Additionally, a more explicit characterization of the texture distribution could enable probabilistic sampling when input queries may be occluded or incomplete." + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 309, + 70, + 545, + 163 + ], + "blocks": [ + { + "bbox": [ + 46, + 535, + 288, + 608 + ], + "lines": [ + { + "bbox": [ + 46, + 535, + 288, + 608 + ], + "spans": [ + { + "bbox": [ + 46, + 535, + 288, + 608 + ], + "type": "text", + "content": "Table 6: Evaluation on texture transfer to ShapeNet chairs and cars from rendered ShapeNet objects as well as real-world image queries from ScanNet chairs and CompCars cars. In this challenging scenario, our mesh-field representation retains more realistic detail in texture optimization. The KID values are scaled by " + }, + { + "bbox": [ + 46, + 535, + 288, + 608 + ], + "type": "inline_equation", + "content": "10^{2}" + }, + { + "bbox": [ + 46, + 535, + 288, + 608 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 309, + 70, + 545, + 163 + ], + "lines": [ + { + "bbox": [ + 309, + 70, + 545, + 163 + ], + "spans": [ + { + "bbox": [ + 309, + 70, + 545, + 163 + ], + "type": "table", + "html": "
MethodChairs ShapeNetCars ShapeNetChairs ScanNetCars CompCars
CLIPCLIPCLIPCLIP
EG3D81.6280.7281.5468.18
Yu et al.81.3178.6981.2164.76
GET3D----
Texturify80.7078.5980.9966.93
Ours83.4782.2081.9577.71
", + "image_path": "c0bd8db6badfe34d4dcd91a0ea3e1d1d2b7ca22836d28cbd718b8bf6f4897219.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 335, + 245, + 517, + 342 + ], + "blocks": [ + { + "bbox": [ + 304, + 171, + 547, + 233 + ], + "lines": [ + { + "bbox": [ + 304, + 171, + 547, + 233 + ], + "spans": [ + { + "bbox": [ + 304, + 171, + 547, + 233 + ], + "type": "text", + "content": "Table 7: Evaluation on texture transfer to ShapeNet chairs and cars from rendered ShapeNet objects as well as real-world image queries from ScanNet chairs and CompCars cars. Our NOC-guided patch style loss enables better characterization of the input query image for texturing." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 335, + 245, + 517, + 342 + ], + "lines": [ + { + "bbox": [ + 335, + 245, + 517, + 342 + ], + "spans": [ + { + "bbox": [ + 335, + 245, + 517, + 342 + ], + "type": "table", + "html": "
MethodChairs (unaligned) ShapeNet
FIDKIDCLIP
w/o NOC124.35.5391.09
w/o patches143.56.9189.68
w/o surf. features127.15.8090.70
w/o glob. style169.610.1288.05
Ours121.15.0891.57
", + "image_path": "20c2a5d203b5b59e215dc0191e222b05026b85fe50a75f625de576771faae549.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 350, + 547, + 399 + ], + "lines": [ + { + "bbox": [ + 304, + 350, + 547, + 399 + ], + "spans": [ + { + "bbox": [ + 304, + 350, + 547, + 399 + ], + "type": "text", + "content": "Table 8: Ablation study on texture transfer optimization design. Our NOC guidance, patch style loss, and surface feature optimization help to improve generated texture quality. The KID values are scaled by " + }, + { + "bbox": [ + 304, + 350, + 547, + 399 + ], + "type": "inline_equation", + "content": "10^{2}" + }, + { + "bbox": [ + 304, + 350, + 547, + 399 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 422, + 378, + 435 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 422, + 378, + 435 + ], + "spans": [ + { + "bbox": [ + 306, + 422, + 378, + 435 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 443, + 547, + 576 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 443, + 547, + 576 + ], + "spans": [ + { + "bbox": [ + 304, + 443, + 547, + 576 + ], + "type": "text", + "content": "We presented Mesh2Tex, which learns a texture manifold based on a hybrid mesh-field representation to generate realistic, high-quality textures on shape geometry from real-world imagery. Mesh2Tex enables test-time optimization for texture transfer from single image queries. Crucially, our NOC-guided local and global style loss enables optimization for perceptually matching textures on a 3D shape that does not require exact geometric matches to RGB image queries. We believe this opens up many new possibilities in texturing for content creation, enabling easy-to-capture images to be used as guidance for holistic shape texturing." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 585, + 547, + 634 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 585, + 547, + 634 + ], + "spans": [ + { + "bbox": [ + 304, + 585, + 547, + 634 + ], + "type": "text", + "content": "Acknowledgements. This work was supported by the Bavarian State Ministry of Science and the Arts coordinated by the Bavarian Research Institute for Digital Transformation (bidt). ST was partially supported by a gift award from CISCO." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 647, + 365, + 661 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 647, + 365, + 661 + ], + "spans": [ + { + "bbox": [ + 306, + 647, + 365, + 661 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 310, + 669, + 547, + 715 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 669, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 310, + 669, + 547, + 715 + ], + "type": "text", + "content": "[1] Armen Avetisyan, Manuel Dahnert, Angela Dai, Manolis Savva, Angel X. Chang, and Matthias Nießner. Scan2cad: Learning CAD model alignment in RGB-D scans. In IEEE Conference on Computer Vision and Pattern Recognition," + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8926" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "text", + "content": "CVPR 2019, Long Beach, CA, USA, June 16-20, 2019, pages 2614-2623, 2019. 5" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 53, + 96, + 287, + 129 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 96, + 287, + 129 + ], + "spans": [ + { + "bbox": [ + 53, + 96, + 287, + 129 + ], + "type": "text", + "content": "[2] Mikołaj Binkowski, Danica J Sutherland, Michael Arbel, and Arthur Gretton. Demystifying mmd gans. arXiv preprint arXiv:1801.01401, 2018. 5" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 130, + 288, + 185 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 130, + 288, + 185 + ], + "spans": [ + { + "bbox": [ + 53, + 130, + 288, + 185 + ], + "type": "text", + "content": "[3] Eric R. Chan, Connor Z. Lin, Matthew A. Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas Guibas, Jonathan Tremblay, Sameh Khamis, Tero Karras, and Gordon Wetzstein. Efficient geometry-aware 3D generative adversarial networks. In arXiv, 2021. 2, 3, 5" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 186, + 288, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 186, + 288, + 239 + ], + "spans": [ + { + "bbox": [ + 53, + 186, + 288, + 239 + ], + "type": "text", + "content": "[4] Angel X Chang, Thomas Funkhouser, Leonidas Guibas, Pat Hanrahan, Qixing Huang, Zimo Li, Silvio Savarese, Manolis Savva, Shuran Song, Hao Su, et al. Shapenet: An information-rich 3d model repository. arXiv preprint arXiv:1512.03012, 2015. 5, 6, 7" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 241, + 288, + 284 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 241, + 288, + 284 + ], + "spans": [ + { + "bbox": [ + 53, + 241, + 288, + 284 + ], + "type": "text", + "content": "[5] Zhiqin Chen and Hao Zhang. Learning implicit fields for generative shape modeling. Proceedings of IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2019. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 286, + 287, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 286, + 287, + 330 + ], + "spans": [ + { + "bbox": [ + 53, + 286, + 287, + 330 + ], + "type": "text", + "content": "[6] Sungjoon Choi, Qian-Yi Zhou, and Vladlen Koltun. Robust reconstruction of indoor scenes. In 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 5556-5565, 2015. 8" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 332, + 288, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 332, + 288, + 374 + ], + "spans": [ + { + "bbox": [ + 53, + 332, + 288, + 374 + ], + "type": "text", + "content": "[7] Manuel Dahnert, Ji Hou, Matthias Nießner, and Angela Dai. Panoptic 3d scene reconstruction from a single rgb image. In Thirty-Fifth Conference on Neural Information Processing Systems, 2021. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 376, + 288, + 431 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 376, + 288, + 431 + ], + "spans": [ + { + "bbox": [ + 53, + 376, + 288, + 431 + ], + "type": "text", + "content": "[8] Angela Dai, Angel X. Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Niessner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In The IEEE Conference on Computer Vision and Pattern Recognition (CVPR), July 2017. 5, 7" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 433, + 288, + 476 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 433, + 288, + 476 + ], + "spans": [ + { + "bbox": [ + 53, + 433, + 288, + 476 + ], + "type": "text", + "content": "[9] Angela Dai, Yawar Siddiqui, Justus Thies, Julien Valentin, and Matthias Nießner. Spsg: Self-supervised photometric scene generation from rgb-d scans. In Proc. Computer Vision and Pattern Recognition (CVPR), IEEE, 2021. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 478, + 288, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 478, + 288, + 510 + ], + "spans": [ + { + "bbox": [ + 48, + 478, + 288, + 510 + ], + "type": "text", + "content": "[10] Yu Deng, Jiaolong Yang, and Xin Tong. Deformed implicit field: Modeling 3d shapes with learned dense correspondence. In IEEE Computer Vision and Pattern Recognition, 2021. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 512, + 288, + 566 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 512, + 288, + 566 + ], + "spans": [ + { + "bbox": [ + 48, + 512, + 288, + 566 + ], + "type": "text", + "content": "[11] Jun Gao, Tianchang Shen, Zian Wang, Wenzheng Chen, Kangxue Yin, Daiqing Li, Or Litany, Zan Gojcic, and Sanja Fidler. Get3d: A generative model of high quality 3d textured shapes learned from images. In Advances In Neural Information Processing Systems, 2022. 3, 5" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 567, + 288, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 567, + 288, + 600 + ], + "spans": [ + { + "bbox": [ + 48, + 567, + 288, + 600 + ], + "type": "text", + "content": "[12] Lin Gao, Tong Wu, Yu-Jie Yuan, Ming-Xian Lin, Yu-Kun Lai, and Hao Zhang. Tm-net: Deep generative networks for textured meshes. 10 2020. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 601, + 288, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 601, + 288, + 645 + ], + "spans": [ + { + "bbox": [ + 48, + 601, + 288, + 645 + ], + "type": "text", + "content": "[13] Leon A Gatys, Alexander S Ecker, and Matthias Bethge. Image style transfer using convolutional neural networks. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 2414-2423, 2016. 4" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 647, + 288, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 288, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 288, + 689 + ], + "type": "text", + "content": "[14] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 4" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 691, + 288, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 288, + 713 + ], + "type": "text", + "content": "[15] Paul Henderson, Vagia Tsiminaki, and Christoph H Lampert. Leveraging 2d data to learn textured 3d mesh generation." + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 326, + 73, + 546, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 546, + 95 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 546, + 95 + ], + "type": "text", + "content": "In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7498-7507, 2020. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 97, + 547, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 97, + 547, + 150 + ], + "spans": [ + { + "bbox": [ + 308, + 97, + 547, + 150 + ], + "type": "text", + "content": "[16] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in neural information processing systems, 30, 2017. 5" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 152, + 547, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 152, + 547, + 217 + ], + "spans": [ + { + "bbox": [ + 308, + 152, + 547, + 217 + ], + "type": "text", + "content": "[17] Jingwei Huang, Justus Thies, Angela Dai, Abhijit Kundu, Chiyu Jiang, Leonidas J Guibas, Matthias Niessner, and Thomas Funkhouser. Adversarial texture optimization from rgb-d scans. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 1559-1568, 2020. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 219, + 547, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 219, + 547, + 274 + ], + "spans": [ + { + "bbox": [ + 308, + 219, + 547, + 274 + ], + "type": "text", + "content": "[18] Jingwei Huang, Yichao Zhou, Matthias Niessner, Jonathan Richard Shewchuk, and Leonidas J Guibas. Quadriflow: A scalable and robust method for quadrangulation. In Computer Graphics Forum, volume 37, pages 147-160. Wiley Online Library, 2018. 4, 7" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 276, + 546, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 276, + 546, + 308 + ], + "spans": [ + { + "bbox": [ + 308, + 276, + 546, + 308 + ], + "type": "text", + "content": "[19] Ajay Jain, Ben Mildenhall, Jonathan T. Barron, Pieter Abbeel, and Ben Poole. Zero-shot text-guided object generation with dream fields. CVPR, 2022. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 309, + 546, + 363 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 309, + 546, + 363 + ], + "spans": [ + { + "bbox": [ + 308, + 309, + 546, + 363 + ], + "type": "text", + "content": "[20] Krishna Murthy Jatavallabhula, Alihusein Kuwajerwala, Qiao Gu, Mohd Omama, Tao Chen, Shuang Li, Ganesh Iyer, Soroush Saryazdi, Nikhil Keetha, Ayush Tewari, et al. Conceptfusion: Open-set multimodal 3d mapping. arXiv preprint arXiv:2302.07241, 2023. 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 365, + 546, + 408 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 365, + 546, + 408 + ], + "spans": [ + { + "bbox": [ + 308, + 365, + 546, + 408 + ], + "type": "text", + "content": "[21] Xie Jianwen, Yifei Xu, Zilong Zheng, Song Zhu, and Ying-nian Wu. Generative pointnet: Energy-based learning on unordered point sets for 3d generation, reconstruction and classification. 04 2020. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 411, + 546, + 443 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 411, + 546, + 443 + ], + "spans": [ + { + "bbox": [ + 308, + 411, + 546, + 443 + ], + "type": "text", + "content": "[22] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of stylegan. CVPR, 2020. 4" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 445, + 546, + 466 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 445, + 546, + 466 + ], + "spans": [ + { + "bbox": [ + 308, + 445, + 546, + 466 + ], + "type": "text", + "content": "[23] Diederik P. Kingma and Jimmy Ba. Adam: A method for stochastic optimization. CoRR, abs/1412.6980, 2014. 5" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 468, + 547, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 468, + 547, + 521 + ], + "spans": [ + { + "bbox": [ + 308, + 468, + 547, + 521 + ], + "type": "text", + "content": "[24] Juil Koo, Ian Huang, Panos Achlioptas, Leonidas J Guibas, and Minhyuk Sung. Partglot: Learning shape part segmentation from language reference games. In Proceedings of IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 523, + 546, + 578 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 523, + 546, + 578 + ], + "spans": [ + { + "bbox": [ + 308, + 523, + 546, + 578 + ], + "type": "text", + "content": "[25] Weicheng Kuo, Anelia Angelova, Tsung-Yi Lin, and Angela Dai. Patch2cad: Patchwise embedding learning for in-the-wild shape retrieval from a single image. 2021 IEEE/CVF International Conference on Computer Vision (ICCV), pages 12569-12579, 2021. 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 580, + 546, + 623 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 580, + 546, + 623 + ], + "spans": [ + { + "bbox": [ + 308, + 580, + 546, + 623 + ], + "type": "text", + "content": "[26] Shitong Luo and Wei Hu. Diffusion probabilistic models for 3d point cloud generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), June 2021. 2" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 624, + 546, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 624, + 546, + 678 + ], + "spans": [ + { + "bbox": [ + 308, + 624, + 546, + 678 + ], + "type": "text", + "content": "[27] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3d reconstruction in function space. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 4460-4470, 2019. 2" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 681, + 546, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 681, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 681, + 546, + 713 + ], + "type": "text", + "content": "[28] Oscar Michel, Roi Bar-On, Richard Liu, Sagie Benaim, and Rana Hanocka. Text2mesh: Text-driven neural stylization for meshes. arXiv preprint arXiv:2112.03221, 2021. 3" + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8927" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 712 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 288, + 106 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 288, + 106 + ], + "type": "text", + "content": "[29] Paritosh Mittal, Yen-Chi Cheng, Maneesh Singh, and Shubham Tulsiani. AutoSDF: Shape priors for 3d completion, reconstruction and generation. In CVPR, 2022. 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 108, + 288, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 108, + 288, + 140 + ], + "spans": [ + { + "bbox": [ + 48, + 108, + 288, + 140 + ], + "type": "text", + "content": "[30] Charlie Nash, Yaroslav Ganin, S. Eslami, and Peter Battaglia. *Polygon: An autoregressive generative model of 3d meshes.* 02 2020. 2" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 143, + 288, + 198 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 143, + 288, + 198 + ], + "spans": [ + { + "bbox": [ + 48, + 143, + 288, + 198 + ], + "type": "text", + "content": "[31] Michael Oechsle, Lars Mescheder, Michael Niemeyer, Thilo Strauss, and Andreas Geiger. Texture fields: Learning texture representations in function space. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 4531-4540, 2019. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 200, + 288, + 244 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 200, + 288, + 244 + ], + "spans": [ + { + "bbox": [ + 48, + 200, + 288, + 244 + ], + "type": "text", + "content": "[32] Michael Oechsle, Lars Mescheder, Michael Niemeyer, Thilo Strauss, and Andreas Geiger. Texture fields: Learning texture representations in function space. In Proceedings IEEE International Conf. on Computer Vision (ICCV), 2019. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 246, + 288, + 300 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 246, + 288, + 300 + ], + "spans": [ + { + "bbox": [ + 48, + 246, + 288, + 300 + ], + "type": "text", + "content": "[33] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. Deepsdf: Learning continuous signed distance functions for shape representation. In 2019 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 165-174, 2019. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 303, + 288, + 346 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 303, + 288, + 346 + ], + "spans": [ + { + "bbox": [ + 48, + 303, + 288, + 346 + ], + "type": "text", + "content": "[34] Keunhong Park, Konstantinos Rematas, Ali Farhadi, and Steven M. Seitz. Photoshape: Photorealistic materials for large-scale shape collections. ACM Trans. Graph., 37(6), Nov. 2018. 2, 5" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 349, + 288, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 349, + 288, + 392 + ], + "spans": [ + { + "bbox": [ + 48, + 349, + 288, + 392 + ], + "type": "text", + "content": "[35] Dario Pavllo, Jonas Kohler, Thomas Hofmann, and Aurelien Lucchi. Learning generative models of textured 3d meshes from real-world images. In IEEE/CVF International Conference on Computer Vision (ICCV), 2021. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 395, + 288, + 460 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 395, + 288, + 460 + ], + "spans": [ + { + "bbox": [ + 48, + 395, + 288, + 460 + ], + "type": "text", + "content": "[36] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International conference on machine learning, pages 8748-8763. PMLR, 2021. 3, 5" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 463, + 288, + 506 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 463, + 288, + 506 + ], + "spans": [ + { + "bbox": [ + 48, + 463, + 288, + 506 + ], + "type": "text", + "content": "[37] Nikhila Ravi, Jeremy Reizenstein, David Novotny, Taylor Gordon, Wan-Yen Lo, Justin Johnson, and Georgia Gkioxari. Accelerating 3d deep learning with pytorch3d. arXiv:2007.08501, 2020.4" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 509, + 288, + 553 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 509, + 288, + 553 + ], + "spans": [ + { + "bbox": [ + 48, + 509, + 288, + 553 + ], + "type": "text", + "content": "[38] David Rozenberszki, Or Litany, and Angela Dai. Language-grounded indoor 3d semantic segmentation in the wild. In Proceedings of the European Conference on Computer Vision (ECCV), 2022. 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 555, + 288, + 609 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 555, + 288, + 609 + ], + "spans": [ + { + "bbox": [ + 48, + 555, + 288, + 609 + ], + "type": "text", + "content": "[39] Shunsuke Saito, Zeng Huang, Ryota Natsume, Shigeo Morishima, Angjoo Kanazawa, and Hao Li. Pifu: Pixel-aligned implicit function for high-resolution clothed human digitization. In The IEEE International Conference on Computer Vision (ICCV), October 2019. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 612, + 288, + 666 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 612, + 288, + 666 + ], + "spans": [ + { + "bbox": [ + 48, + 612, + 288, + 666 + ], + "type": "text", + "content": "[40] Shunsuke Saito, Tomas Simon, Jason Saragih, and Hanbyul Joo. Pifuhd: Multi-level pixel-aligned implicit function for high-resolution 3d human digitization. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, June 2020. 2" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 670, + 288, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 288, + 712 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 288, + 712 + ], + "type": "text", + "content": "[41] Aditya Sanghi, Hang Chu, Joseph G Lambourne, Ye Wang, Chin-Yi Cheng, and Marco Fumero. Clip-forge: Towards zero-shot text-to-shape generation. arXiv preprint arXiv:2110.02624, 2021. 3" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 72, + 546, + 565 + ], + "type": "list", + "angle": 0, + "index": 25, + "blocks": [ + { + "bbox": [ + 307, + 72, + 546, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 72, + 546, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 72, + 546, + 106 + ], + "type": "text", + "content": "[42] Yawar Siddiqui, Justus Thies, Fangchang Ma, Qi Shan, Matthias Nießner, and Angela Dai. Texturify: Generating textures on 3d shape surfaces, 2022. 2, 4, 5, 8" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 108, + 546, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 108, + 546, + 139 + ], + "spans": [ + { + "bbox": [ + 307, + 108, + 546, + 139 + ], + "type": "text", + "content": "[43] Mingxing Tan and Quoc V. Le. Efficientnet: Rethinking model scaling for convolutional neural networks. In ICML, 2019. 4" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 141, + 546, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 141, + 546, + 173 + ], + "spans": [ + { + "bbox": [ + 307, + 141, + 546, + 173 + ], + "type": "text", + "content": "[44] Can Wang, Menglei Chai, Mingming He, Dongdong Chen, and Jing Liao. Clip-nerf: Text-and-image driven manipulation of neural radiance fields. ArXiv, abs/2112.05139, 2021. 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 175, + 546, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 175, + 546, + 239 + ], + "spans": [ + { + "bbox": [ + 307, + 175, + 546, + 239 + ], + "type": "text", + "content": "[45] He Wang, Srinath Sridhar, Jingwei Huang, Julien Valentin, Shuran Song, and Leonidas J Guibas. Normalized object coordinate space for category-level 6d object pose and size estimation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 2642-2651, 2019. 3, 4" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 241, + 546, + 307 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 241, + 546, + 307 + ], + "spans": [ + { + "bbox": [ + 307, + 241, + 546, + 307 + ], + "type": "text", + "content": "[46] Qiangeng Xu, Weiyue Wang, Duygu Ceylan, Radomir Mech, and Ulrich Neumann. Disn: Deep implicit surface network for high-quality single-view 3d reconstruction. In H. Wallach, H. Larochelle, A. Beygelzimer, F. d'Alché-Buc, E. Fox, and R. Garnett, editors, Advances in Neural Information Processing Systems 32, pages 492-502. Curran Associates, Inc., 2019. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 308, + 546, + 362 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 308, + 546, + 362 + ], + "spans": [ + { + "bbox": [ + 307, + 308, + 546, + 362 + ], + "type": "text", + "content": "[47] Qiangeng Xu, Zexiang Xu, Julien Philip, Sai Bi, Zhixin Shu, Kalyan Sunkavalli, and Ulrich Neumann. Point-nerf: Point-based neural radiance fields. 2022 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 5428–5438, 2022. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 364, + 546, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 364, + 546, + 407 + ], + "spans": [ + { + "bbox": [ + 307, + 364, + 546, + 407 + ], + "type": "text", + "content": "[48] Bangbang Yang, Chong Bao, Junyi Zeng, Hujun Bao, Yinda Zhang, Zhaopeng Cui, and Guofeng Zhang. Neumesh: Learning disentangled neural mesh-based implicit field for geometry and texture editing. 07 2022. 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 409, + 546, + 461 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 409, + 546, + 461 + ], + "spans": [ + { + "bbox": [ + 307, + 409, + 546, + 461 + ], + "type": "text", + "content": "[49] Linjie Yang, Ping Luo, Chen Change Loy, and Xiaou Tang. A large-scale car dataset for fine-grained categorization and verification. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3973-3981, 2015. 5" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 464, + 546, + 497 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 464, + 546, + 497 + ], + "spans": [ + { + "bbox": [ + 307, + 464, + 546, + 497 + ], + "type": "text", + "content": "[50] Rui Yu, Yue Dong, Pieter Peers, and Xin Tong. Learning texture generators for 3d shape collections from internet photo sets. In *British Machine Vision Conference*, 2021. 5" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 498, + 546, + 531 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 498, + 546, + 531 + ], + "spans": [ + { + "bbox": [ + 307, + 498, + 546, + 531 + ], + "type": "text", + "content": "[51] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In CVPR, 2018. 5" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 532, + 546, + 565 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 532, + 546, + 565 + ], + "spans": [ + { + "bbox": [ + 307, + 532, + 546, + 565 + ], + "type": "text", + "content": "[52] Qian-Yi Zhou and Vladlen Koltun. Color map optimization for 3d reconstruction with consumer depth cameras. ACM Transactions on Graphics, 33, 08 2014. 2" + } + ] + } + ], + "index": 24 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "8928" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/06d792b4-9c42-4f8e-baa6-449a229309f7_content_list.json b/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/06d792b4-9c42-4f8e-baa6-449a229309f7_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..c39845e6b8daee33fd0e7702a2944d0e843889b8 --- /dev/null +++ b/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/06d792b4-9c42-4f8e-baa6-449a229309f7_content_list.json @@ -0,0 +1,1805 @@ +[ + { + "type": "text", + "text": "Meta OOD Learning For Continuously Adaptive OOD Detection", + "text_level": 1, + "bbox": [ + 156, + 130, + 813, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Xinheng Wu† Jie Lu† Zhen Fang† Guangquan Zhang†", + "bbox": [ + 267, + 179, + 702, + 199 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "†Australian Artificial Intelligence Institute, University of Technology Sydney", + "bbox": [ + 181, + 199, + 787, + 217 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Xinheng.Wu@student.uts.edu.au {Jie.Lu, Zhen.Fang, Guangquan.Zhang}@uts.edu.au*", + "bbox": [ + 135, + 219, + 838, + 234 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 268, + 313, + 284 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Out-of-distribution (OOD) detection is crucial to modern deep learning applications by identifying and alerting about the OOD samples that should not be tested or used for making predictions. Current OOD detection methods have made significant progress when in-distribution (ID) and OOD samples are drawn from static distributions. However, this can be unrealistic when applied to real-world systems which often undergo continuous variations and shifts in ID and OOD distributions over time. Therefore, for an effective application in real-world systems, the development of OOD detection methods that can adapt to these dynamic and evolving distributions is essential. In this paper, we propose a novel and more realistic setting called continuously adaptive out-of-distribution (CAOD) detection which targets on developing an OOD detection model that enables dynamic and quick adaptation to a new arriving distribution, with insufficient ID samples during deployment time. To address CAOD, we develop meta OOD learning (MOL) by designing a learning-to-adapt diagram such that a good initialized OOD detection model is learned during the training process. In the testing process, MOL ensures OOD detection performance over shifting distributions by quickly adapting to new distributions with a few adaptations. Extensive experiments on several OOD benchmarks endorse the effectiveness of our method in preserving both ID classification accuracy and OOD detection performance on continuously shifting distributions.", + "bbox": [ + 75, + 300, + 473, + 709 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 734, + 209, + 752 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Out-of-distribution (OOD) detection is vital to modern deep learning (DL) applications in the real world, especially in safety-critical applications such as autonomous vehicle control [21], and medical areas [64]. This is because DL systems may make over-confident and incorrect predictions when encountering the out-of-distribution (OOD) samples, which possess semantic labels that are distinct from those", + "bbox": [ + 75, + 761, + 468, + 867 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/9074d848afddb7d879dfd4391f528393b7a4670a1fa560a8d108a14404cc2d1c.jpg", + "image_caption": [ + "Figure 1: Difference between existing static OOD detection and a more realistic scenario of Continuously Adaptive OOD Detection (Problem 1) when test samples come from continuously shifting distribution, i.e., Definition 1." + ], + "image_footnote": [], + "bbox": [ + 503, + 271, + 893, + 460 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "of in-distribution (ID) samples [63]. To mitigate this issue, an important problem out-of-distribution detection has been proposed and studied extensively [10, 17]. In OOD detection, the classifier is required to perform accurate predictions on ID samples while simultaneously identifying OOD samples. Many representative methods either utilize outputs [17, 34], feature representations [29, 45], or gradients [19, 32] to enlarge the separations between ID and OOD samples, while others [18, 39] incorporate auxiliary OOD samples to regularize the deep models during training.", + "bbox": [ + 496, + 551, + 893, + 703 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Although OOD detection has achieved great progress, existing methods only focus on a simple scenario where ID and OOD samples are assumed to be drawn from static ID and OOD distributions. However, many real-world systems are changing dynamically and thus inherently exhibit continuous distribution shifts over time. Take a self-driving agent equipped with a scene recognition system as an example: in the real world, the surrounding environment (e.g., illumination, weather) may shift continuously on the road, such as from day to night, and from clean to foggy. Treating the arriving training and test samples as from static distributions may potentially harm the effectiveness of OOD detection, leading to the misclassification of distribution-shifted", + "bbox": [ + 496, + 704, + 895, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Corresponding to Jie Lu and Zhen Fang. The work is supported by the Australian Research Council under Discovery Grant DP200100700.", + "bbox": [ + 76, + 875, + 468, + 900 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "19353", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "ID and OOD samples. Such scenarios highlight the limitations of current OOD detection methods when applied to continuously shifting distributions. Figure 1 highlights the difference between OOD detection on static distribution and when applying to continuously shifting distributions.", + "bbox": [ + 75, + 90, + 468, + 167 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To tackle the continuously shifting scenarios in OOD detection, we propose a novel and realistic setting termed continuously adaptive out-of-distribution (CAOOD) detection, which targets on developing OOD detection method to 1) quickly adapt to the continuously shifting ID distributions and 2) detect the continuously shifting OOD samples over time. Note that during the deployment time, the ID samples may be insufficient during the adaptation process. Therefore, how to enable dynamic and quick adaptation with insufficient ID samples to achieve good OOD detection performance over time is core challenge of CAOOD detection.", + "bbox": [ + 75, + 169, + 468, + 335 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Inspired by domain adaptation [14, 6] and meta-learning [13], we develop a novel and effective CAOD detection method called meta out-of-distribution learning (MOL) to address the challenge in CAOD detection. To dynamically and quickly adapt to the continuously shifting ID samples, we leverage the learning-to-learn paradigm [52] of meta-learning which aims to learn an internal representation for quick adaptation to a new task. Specifically, by formulating adaptations to the continuous shifting ID samples as a variety of inner tasks, we design a meta-training procedure for learning to adapt explicitly. Further, to facilitate quick adaptation with insufficient ID samples, we propose to learn a meta-representation during training, which allows us to only update the light-weighted classifier during testing while keeping the meta-representation fixed. Additionally, considering OOD samples are unavailable in training, we propose to generate OOD samples based on the shifting ID feature representations. Lastly, the classifier is trained discriminatively based on both ID and virtual OOD samples.", + "bbox": [ + 75, + 337, + 470, + 625 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The contributions are summarized as follows:", + "bbox": [ + 96, + 627, + 398, + 641 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose a more realistic OOD detection setting called CAOD detection to promote the applications of OOD detection techniques in real-world scenarios.", + "- We develop technologies based on meta-learning and domain adaptation to quickly adapt to the continuously shifting ID distributions. With these technologies, MOL is proposed to address CAOD detection.", + "- We conduct extensive experiments comparing MOL with competitive OOD detection methods using various fine-tuning/adaptation strategies on 114 CAOOD detection tasks. Experiments show that MOL achieves the best performance for both ID classification and OOD detection in continuously shifting distributions." + ], + "bbox": [ + 94, + 664, + 468, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 89, + 640, + 106 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Out-of-distribution Detection methods are mainly post-hoc based adopting different scoring functions based on either logit outputs [17, 32, 34, 46, 28, 20], feature representations [45, 29, 33, 54, 47], or gradients [32, 19, 22]. These methods enjoy good applicability when deployed as they can be easily integrated into a pre-trained model without retraining. Other works utilize contrastive learning [48, 47, 55], specifically designed loss functions [60, 38, 40]. However, these methods often require sophisticated score functions but may not necessarily outperform post-hoc methods in general as noted by [63]. Another line of OOD detection methods focus on regularizing the training of classifier using either auxiliary OOD datasets or generated fake OOD samples [18, 30, 34]. These works study sampling strategies [39, 3, 31], OOD samples generation approaches [30, 51, 8], and uncertainty regularization mechanisms [50]. In addition to above strategies, other strategies have also been explored. For example, to overcome the intrinsic inconsistency of prior metrics by aggregating both the known and unknown class performance in a single performance curve, [59] propose a novel OOD detection metric named OpenAUC as the final objective function to learn OOD detector.", + "bbox": [ + 496, + 114, + 890, + 446 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Above OOD detection methods neglect inevitable distribution shifts in test data over time in real-world applications. Very few OOD detection works consider such shift: one work [62] used a large unlabeled dataset containing ID samples aiming to encourage ID semantic information modeling while being robust to covariate shift. Another work [65] considers explicitly promotes the generalization capacity of the OOD detector when being evaluated on covariate-shifted ID data. Recent work [41] discovers that environmental-related features (e.g., backgrounds) significantly worsen existing OOD detection performance. These early attempts highlight existing OOD detection methods are prone to distribution shifts and consequently inadequate for realistic scenarios, which motivates our research.", + "bbox": [ + 496, + 448, + 890, + 657 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Domain Adaptation (DA) aims to adapt machine learning models to unseen and different distributions [12, 64, 67, 7]. In complementary to OOD detection, DA improves models' generalization ability to covariate shift when test data share the same label set as training [35, 4]. Most existing DA methods focus on matching discrete source and target domains leveraging domain statistics [42], distance-based loss functions [37], and adversarial training [14]. Recently, different methods are developed to perform continuous domain adaptation when the target domain shifts smoothly over time [2, 53, 56]. Continuous domain adaptation is related to our problem but it does not follow an open-world assumption where test data may contain OOD samples that do not belong to the training label set. In this paper, we address a more challenging open-world learning scenario, OOD detection under continuous shifting distributions.", + "bbox": [ + 496, + 659, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "19354", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Open World Recognition aims to incrementally learn new information without forgetting in an open world [24, 1, 11]. This problem concentrates on zero-shot learning [44], mitigating catastrophic forgetting [25], and incremental learning [43], where unknown samples can be progressively labeled as inputs. This is different from our focus on learning an open-world classifier that can quickly adapt to continuously shifted domains online while maintaining both ID and OOD detection performance. Additional literature on the topic of meta-learning is included in the Appendix.", + "bbox": [ + 75, + 90, + 472, + 243 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Problem Setup and Notations", + "text_level": 1, + "bbox": [ + 76, + 258, + 349, + 275 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "OD Detection. Let $\\mathcal{X}$ denote the feature space, $\\mathcal{Y} = [C]$ be the label space. We consider the ID distribution $D_{X_1Y_1}$ as a joint distribution defined over $\\mathcal{X}\\times \\mathcal{Y}$ , where $X_{\\mathrm{I}}$ and $Y_{\\mathrm{I}}$ are random variables whose outputs are from spaces $\\mathcal{X}$ and $\\mathcal{Y}$ . Given a set of $n$ samples drawn i.i.d. from the ID distribution called ID data, $S = \\{(\\mathbf{x}_j,y_j)\\}_{j = 1}^n\\sim D_{X_1Y_1}$ . A classic classification model $\\mathbf{f}:\\mathcal{X}\\to \\mathbb{R}^{C}$ , is trained on the training set $S$ , to predict the label of an input test data [10].", + "bbox": [ + 75, + 282, + 468, + 407 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "During the test time of OOD detection, the test samples contain some unknown OOD samples drawn from an OOD distribution $D_{X_0Y_0}$ , where $X_0$ is a random variable from $\\mathcal{X}$ , but $Y_0$ is a random variable whose outputs do not belong to $\\mathcal{Y}$ , i.e., $Y_0 \\notin \\mathcal{Y}$ . The classical OOD detection methods aim to design an effective score function $s(\\cdot; \\mathbf{f}): \\mathcal{X} \\to \\mathbb{R}$ [32, 29, 34] and train a corresponding model $\\mathbf{f}$ by ID samples $S$ such that the following OOD detector", + "bbox": [ + 75, + 407, + 468, + 527 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nG _ {\\gamma} (\\mathbf {x}; s, \\mathbf {f}) = \\left\\{ \\begin{array}{l l} \\text {I D} & \\text {i f} s (\\mathbf {x}; \\mathbf {f}) \\geq \\gamma \\\\ \\text {O O D} & \\text {i f} s (\\mathbf {x}; \\mathbf {f}) < \\gamma \\end{array} \\right. \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 140, + 542, + 468, + 574 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\gamma$ is a threshold can distinguish ID and OOD samples accurately. In this paper, we select $\\gamma$ when $95\\%$ ID data is correctly classified [63, 58, 57], and use energy score [34] as the scoring function to design our OOD detector, i.e.,", + "bbox": [ + 75, + 583, + 468, + 643 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\ns (\\mathbf {x}; \\mathbf {f}) = \\log \\sum_ {l = 1} ^ {C} \\exp (f _ {l} (\\mathbf {x})) \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 174, + 657, + 468, + 698 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $f_{l}(\\mathbf{x})$ is the $l$ -th coordinate of $\\mathbf{f}(\\mathbf{x})$ .", + "bbox": [ + 76, + 707, + 356, + 723 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Continuously Adaptive OOD Detection. To tackle more realistic scenarios that the ID and OOD samples are from continuously shifting distributions over a discrete time period $T = \\{t_1, t_2, \\dots, t_N\\}$ , which satisfies that $0 < t_1 < t_2 < \\dots < t_N$ . We also set $T_k = \\{t_1, t_2, \\dots, t_k\\}$ and set $T_K^- = \\{t_K, t_{K+1}, \\dots, t_N\\}$ , where $1 \\leq k < K \\leq N$ . It is clear that $T_k \\cup T_K^- \\subset T$ and $T_k \\cap T_K^- = \\emptyset$ . Next, the definition of continuously shifting ID and OOD distributions is given in Definition 1.", + "bbox": [ + 75, + 738, + 468, + 875 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/7fe2311f62c252f98969cdc3178bd8fe9b74118ac199578b4527867524a2c396.jpg", + "image_caption": [ + "Figure 2: A heuristic illustration CAOD problem. The target is to train an OOD detection model $g_{0}$ using S, $\\{S^t\\}_{t \\in T_k}$ so it can obtain good OOD detection performance on unseen shifting samples $\\{S^t\\}_{t \\in T_K^-}$ by quick adaptation." + ], + "image_footnote": [], + "bbox": [ + 501, + 90, + 883, + 220 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Definition 1 (Continuously Shifting Distributions.) Let $D_{X_1Y_1}^t$ and $D_{X_0Y_0}^t$ are $ID$ and OOD joint distributions at time $t \\in T$ . We say $D_{X_1Y_1}^t, D_{X_0Y_0}^t$ are continuously shifting $ID$ and OOD distributions, if for any $i \\in [N-1]$ ,", + "bbox": [ + 498, + 311, + 890, + 375 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} d \\left(D _ {X _ {1} Y _ {1}} ^ {t _ {i}}, D _ {X _ {1} Y _ {1}} ^ {t _ {i + 1}}\\right) < \\epsilon , \\\\ d (D _ {X _ {\\mathrm {O}}} ^ {t _ {i}}, D _ {X _ {\\mathrm {O}}} ^ {t _ {i + 1}}) < \\epsilon , \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 617, + 383, + 771, + 428 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $d(\\cdot, \\cdot)$ is a distribution metric and $\\epsilon$ is a small value.", + "bbox": [ + 500, + 436, + 885, + 452 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In Definition 1, the small value $\\epsilon$ is used to estimate the gradual variations and quantify the continuity of continuously shifting ID and OOD distributions. We note here that distribution shift over time can be significant as it gradually accumulates. Next, we give the definition of continuously adaptive OOD detection.", + "bbox": [ + 498, + 464, + 890, + 555 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Problem 1 (Continuously Adaptive OOD Detection.)", + "text_level": 1, + "bbox": [ + 498, + 566, + 867, + 582 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Let $D_{X_{\\mathrm{I}}Y_{\\mathrm{I}}}^{t}$ and $D_{X_{\\mathrm{O}}Y_{\\mathrm{O}}}^{t}$ be the continuously shifting ID and OOD distributions over time period $T$ and let $D_{X_{\\mathrm{I}}Y_{\\mathrm{I}}}$ be the original ID distribution. Given sets of samples", + "bbox": [ + 498, + 582, + 890, + 628 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nS = \\left\\{\\left(\\mathbf {x} _ {1}, y _ {1}\\right), \\dots , \\left(\\mathbf {x} _ {n}, y _ {n}\\right) \\right\\} \\sim D _ {X _ {1} Y _ {1}}, i. i. d.\n$$\n", + "text_format": "latex", + "bbox": [ + 560, + 638, + 862, + 656 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nS ^ {t} = \\left\\{\\mathbf {x} _ {1} ^ {t}, \\dots , \\mathbf {x} _ {n} ^ {t} \\right\\} \\sim D _ {X _ {1}} ^ {t}, i. i. d., f o r e a c h t \\in T\n$$\n", + "text_format": "latex", + "bbox": [ + 527, + 657, + 864, + 676 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "with $n^t \\ll n$ if $t \\in T_K^-$ , the aim of continuously adaptive OOD detection is to train an initial OOD detection model $g_0$ using $S$ , $\\{S^t\\}_{t \\in T_k}$ , and to quickly update the model $g_{t_i}$ (at each time $t_i \\in T_K^- = \\{t_K, t_{K+1}, \\dots, t_N\\}$ ) based on the previous model $g_{t_{i-1}}$ ( $g_0$ is the initial model, i.e., $g_{t_{K-1}} = g_0$ ) using $S$ , $S^{t_i}$ . Such that for any test sample $\\mathbf{x} \\in \\{S^t\\}_{t \\in T_K^-}$ : 1) if $\\mathbf{x}$ is from ID distribution $D_{X_1}^t$ , $g_{t_N}$ classifies $\\mathbf{x}$ into correct ID label; and 2) if $\\mathbf{x}$ is from OOD distribution $D_{X_0}^t$ , $g_{t_N}$ detects $\\mathbf{x}$ as OOD.", + "bbox": [ + 498, + 688, + 890, + 829 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "A heuristic illustration of the CAOD problem is provided in Figure 2. The key challenge of Problem 1 is to quickly adapt to new ID distribution $D_{X_1}^{t_i}$ using insufficient ID samples $S^{t_i}$ at time $t_i$ . To achieve satisfied performance", + "bbox": [ + 498, + 839, + 890, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_footnote", + "text": "1We use [N] to represent set {1,..., N}. Therefore, $[C] = \\{1,\\dots,C\\}$ .", + "bbox": [ + 94, + 886, + 467, + 901 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "19355", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "across time period $T_{K}^{-}$ , a good initial OOD detection model $g_{0}$ is indispensable for effective adaptation. In Section 4, we illustrate the proposed MOL method and detail how to obtain the initial model $g_{0}$ during the training procedure.", + "bbox": [ + 75, + 90, + 468, + 151 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Notations. To facilitate better comprehension, we introduce some necessary notations. To learn a good initial OOD detection model $g_{0}$ , we mainly use meta-learning techniques. Following the meta-training procedure [13], we need to sample a support set $\\mathbf{S}_{\\mathrm{spt}} = \\{S_{\\mathrm{spt}}^{t}\\}_{t\\in T_{k}^{\\prime}}$ from $\\{S^t\\}_{t\\in T_k}$ where $T_{k}^{\\prime}\\subset T_{k}$ and $S_{\\mathrm{spt}}^{t}\\subset S^{t}$ . We also need to sample a query set $\\mathbf{S}_{\\mathrm{qry}} = \\{S_{\\mathrm{qry}}^{t}\\}_{t\\in T_{k}^{\\prime}}$ from $\\{S^t\\}_{t\\in T_k}$ , where $S_{\\mathrm{qry}}^{t}\\subset S^{t}$ . Further, we set $\\mathbf{f}_{\\Theta}$ to be the feature extractor, set $\\mathbf{h}_{\\Phi}$ to be the adapter, and set $\\mathbf{c}_W$ to be the classifier, where $\\Theta ,\\Phi$ and $W$ are the parameters. Then the classification model $\\mathbf{f}$ can be expressed as a function composition:", + "bbox": [ + 75, + 152, + 470, + 321 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {f} _ {W, \\Phi , \\Theta} = \\mathbf {c} _ {W} \\circ \\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta}.\n$$\n", + "text_format": "latex", + "bbox": [ + 187, + 330, + 356, + 347 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Lastly, the OOD detection model $G_{\\gamma}$ can be obtained via the score function $s(\\cdot ;\\mathbf{f}_{W,\\Phi ,\\Theta})$ as shown in Eqs. 1 and 2.", + "bbox": [ + 75, + 357, + 468, + 388 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To adapt the shifting distributions, we mainly utilize the maximum mean discrepancy (MMD) [15], which are introduced in following: given samples $\\{\\mathbf{x}_i\\}_{i=1}^n$ and $\\{\\mathbf{x}_j'\\}_{j=1}^m$ ,", + "bbox": [ + 75, + 388, + 468, + 435 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} d _ {k} (\\{\\mathbf {x} _ {i} \\} _ {i = 1} ^ {n}, \\{\\mathbf {x} _ {j} ^ {\\prime} \\} _ {j = 1} ^ {m}) \\\\ = \\left\\| \\frac {1}{n} \\sum_ {i = 1} ^ {n} \\phi_ {k} (\\mathbf {x} _ {i}) - \\frac {1}{m} \\sum_ {i = 1} ^ {m} \\phi_ {k} (\\mathbf {x} _ {j}) \\right\\| _ {k}, \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 148, + 446, + 397, + 505 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $k$ is the kernel and $\\phi_{k}$ is the kernel feature map. To further improve the adaptive performance, in this work, we use the multi-kernel MMD $d_{mk}$ , which is shown in [36].", + "bbox": [ + 75, + 513, + 468, + 559 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. Methodology", + "text_level": 1, + "bbox": [ + 76, + 573, + 210, + 589 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "It is important to recognize that while the number of test samples $S^t (t \\in T_K^-)$ may be limited during deployment, we often have access to a satisfactory number of labeled training samples $S$ as well as unlabeled samples $\\{S^t\\}_{t \\in T_k}$ that can be used to simulate distribution shifts that may occur during deployment. This motivates us to learn a well-designed initial OOD detection model $g_0$ that utilizes both labeled training samples $S$ and unlabeled samples $\\{S^t\\}_{t \\in T_k}$ to effectively adapt to the shifting test samples $S^t (t \\in T_K^-)$ as defined in Problem 1.", + "bbox": [ + 75, + 598, + 468, + 747 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To develop an effective initial OOD detection model $g_0$ , we consider learning an internal meta-representation that enables efficient adaptation to the new distributions in Problem 1. Additionally, note that OOD samples are unavailable during the training process, we utilize the virtual OOD synthesize [8] techniques to generate reliable-virtual OOD samples. The virtual OOD samples emulate real OOD samples and thus enable the classifier to be trained with an additional uncertainty regularization term that incorporates both ID and virtual OOD information.", + "bbox": [ + 75, + 750, + 468, + 898 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "An effective strategy of learning $g_{0}$ is to draw upon the experience of meta-learning [9, 52]. Originally proposed for addressing few-shot learning [9, 23], meta-learning involves utilizing fast adaptation on a small number of samples. By using meta-learning [13], we can efficiently adapt the initial model to new distributions encountered during deployment. Specifically, a meta-training process is explicitly designed for learning-to-adapt by viewing the adaptation to each time $t \\in T_k'$ for OOD detection as the inner tasks, thus dynamic adaptations across all time periods $T_k'$ can be regarded as one input for the outer-loop training process. Concretely, we can train the classifier by considering both ID adaptation and OOD uncertainty regularization. In the outer loop, we update the model with respect to many inner tasks across all time periods $T_k'$ . We detail the inner learning tasks and outer-loop meta-training process in Sections 4.1 and 4.2. The entire procedures of the proposed MOL method are shown in Algorithms 1 and 2.", + "bbox": [ + 496, + 90, + 890, + 363 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Inner Learning Task for MOL", + "text_level": 1, + "bbox": [ + 498, + 375, + 769, + 390 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "ID Adaptation. In the inner task, we firstly train the adapter $\\mathbf{h}_{\\Phi}$ and classifier $\\mathbf{c}_W$ to adapt to current ID distribution at time point $t \\in T_k'$ using support set $\\mathbf{S}_{\\mathrm{spt}}$ . Specifically, given a cross-entropy loss $\\ell_{\\mathrm{ce}}$ and multi-kernel MMD $d_{mk}$ , we minimize the following objective.", + "bbox": [ + 496, + 398, + 890, + 474 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\min _ {\\Phi , W} \\left[ \\mathcal {L} _ {\\mathrm {c e}} + \\mathcal {L} _ {\\mathrm {d}} ^ {t} \\right] = \\min _ {\\Phi , W} \\left[ \\frac {1}{n} \\sum_ {i = 1} ^ {n} \\ell_ {\\mathrm {c e}} \\left(\\mathbf {f} _ {\\Theta , \\Phi , W} \\left(\\mathbf {x} _ {i}\\right), y _ {i}\\right) \\right. \\tag {3} \\\\ \\left. \\right. + d _ {m k} ^ {2} \\big (\\{\\mathbf {f} _ {\\Theta , \\Phi , W} (\\mathbf {x} _ {i}) \\} _ {i = 1} ^ {n}, \\{\\mathbf {f} _ {\\Theta , \\Phi , W} (\\mathbf {x} _ {j, \\mathrm {s p t}} ^ {t}) \\} _ {j = 1} ^ {m ^ {t}} \\big) \\big ], \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 509, + 488, + 890, + 550 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\{\\mathbf{x}_{j,\\mathrm{spt}}^t\\}_{j = 1}^m = S_{\\mathrm{spt}}^t$ . Then at each time $t\\in T_k^\\prime$ , we estimate the empirical mean and covariance of training samples $S$ for each class $c\\in \\mathcal{V}$ using $\\mathbf{h}_{\\Phi}\\circ \\mathbf{f}_{\\Theta}$ [29],", + "bbox": [ + 496, + 564, + 890, + 611 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {\\boldsymbol {\\mu}} _ {c} ^ {t} = \\frac {1}{n _ {c}} \\sum_ {i: y _ {i} = c} \\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta} \\left(\\mathbf {x} _ {i}\\right), \\quad \\hat {\\boldsymbol {\\Sigma}} ^ {t} = \\frac {1}{n} \\sum_ {c = 1} ^ {C} \\hat {\\boldsymbol {\\Sigma}} _ {c} ^ {t}, \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 524, + 623, + 890, + 666 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $n_c$ is the number of samples $S$ for class $c$ , and", + "bbox": [ + 500, + 679, + 849, + 694 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {\\boldsymbol {\\Sigma}} _ {c} ^ {t} = \\sum_ {i: y _ {i} = c} ^ {n} \\left(\\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta} \\left(\\mathbf {x} _ {i}\\right) - \\hat {\\boldsymbol {\\mu}} _ {c} ^ {t}\\right) \\left(\\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta} \\left(\\mathbf {x} _ {i}\\right) - \\hat {\\boldsymbol {\\mu}} _ {c} ^ {t}\\right) ^ {\\top}.\n$$\n", + "text_format": "latex", + "bbox": [ + 500, + 707, + 877, + 747 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Note that the adapter $\\mathbf{h}_{\\Phi}$ is updated by the training objective in Eq. (3) at each time $t\\in T_k^{\\prime}$ .", + "bbox": [ + 496, + 760, + 890, + 790 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Virtual OOD Generation. We generate virtual OOD samples based on the updated ID features $\\mathbf{h}_{\\Phi} \\circ \\mathbf{f}_{\\Theta}$ at each time $t \\in T_k'$ . Motivated by [8, 29], we also assume that adapted class-conditional ID distribution $D_{\\mathbf{h}_{\\Phi} \\circ \\mathbf{f}_{\\Theta}(X_{\\mathrm{I}}) | Y_{\\mathrm{I}} = c}^{t}$ is similar to a multivariate Gaussian distribution, i.e.,", + "bbox": [ + 496, + 791, + 890, + 866 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nD _ {\\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta} (X _ {\\mathrm {I}}) | Y _ {\\mathrm {I}} = c} ^ {t} \\approx \\mathcal {N} \\left(\\hat {\\mu} _ {c} ^ {t}, \\hat {\\Sigma} ^ {t}\\right),\n$$\n", + "text_format": "latex", + "bbox": [ + 583, + 878, + 807, + 904 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "19356", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "which implies that we can sample virtual OOD samples $Z_{c}^{t}$ at the adapted feature space $\\mathcal{Z} = \\mathbf{h}_{\\Phi}\\circ \\mathbf{f}_{\\Theta}(\\mathcal{X})\\subset \\mathbb{R}^{\\tilde{d}}$ to each class $c$ in the $\\delta$ -likelihood region, i.e., $Z_{c}^{t}$ is sampled from", + "bbox": [ + 76, + 90, + 468, + 140 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\left\\{\\mathbf {z} _ {c} ^ {t} \\mid \\frac {A}{| \\hat {\\boldsymbol {\\Sigma}} | ^ {1 / 2}} \\exp \\left(\\left(\\mathbf {z} _ {c} ^ {t} - \\hat {\\boldsymbol {\\mu}} _ {c} ^ {t}\\right) \\hat {\\boldsymbol {\\Sigma}} ^ {- 1} \\left(\\mathbf {z} _ {c} ^ {t} - \\hat {\\boldsymbol {\\mu}} _ {c} ^ {t}\\right)\\right) < \\delta \\right\\}, \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 91, + 146, + 468, + 180 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $A = 1 / (2\\pi)^{\\tilde{d} /2}$ and $\\delta$ is a small constant to ensure that the sampled OOD samples $Z_{c}^{t}$ are near the estimated class boundary in the adapted feature space $\\mathcal{Z}$ .", + "bbox": [ + 76, + 190, + 468, + 238 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Inner Uncertainty Regularization. By the above steps, at each time $t \\in T_k'$ , we obtained the adapting ID information and the virtual OOD samples at the adapted feature space $\\mathcal{Z}$ . Now we add an extra regularization term such that the classifier $\\mathbf{c}_W$ can classify the adapted ID samples and virtual OOD samples in the adapted feature space $\\mathcal{Z}$ . Specifically, the regularization term [8] is shown in following,", + "bbox": [ + 75, + 239, + 468, + 345 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {L} _ {\\mathrm {o o d}} ^ {t} = \\frac {1}{C} \\sum_ {c = 1} ^ {C} \\mathbb {E} _ {\\mathbf {z} \\sim \\mathcal {Z} _ {c} ^ {t}} \\left[ - \\log \\frac {1}{1 + \\exp^ {s (\\mathbf {z} ; \\mathbf {c} _ {W})}} \\right] \\tag {6} \\\\ + \\mathbb {E} _ {\\mathbf {x} \\sim S _ {\\mathrm {s p t}} ^ {t}} \\left[ - \\log \\frac {\\exp^ {s (\\mathbf {x} ; \\mathbf {f} _ {W , \\Phi , \\Theta})}}{1 + \\exp^ {s (\\mathbf {x} ; \\mathbf {f} _ {W , \\Phi , \\Theta})}} \\right], \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 114, + 353, + 468, + 431 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where the score function $s$ is introduced in Eq. (2). Therefore, we obtain the optimization problem for inner tasks by combining Eq. (3) and (6), i.e., for a parameter $\\lambda > 0$ ,", + "bbox": [ + 76, + 438, + 468, + 483 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\min _ {W, \\Phi} \\mathcal {L} ^ {t} = \\min _ {W, \\Phi} \\left[ \\mathcal {L} _ {\\mathrm {c e}} + \\mathcal {L} _ {\\mathrm {d}} ^ {t} + \\lambda \\mathcal {L} _ {\\mathrm {o o d}} ^ {t} \\right]. \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 148, + 489, + 468, + 513 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Note that at the earlier training stage, we optimize $\\Phi$ , $W$ only by using Eq. (3) so that a good estimation of ID distribution can be learned. Specifically, following VOS [8], we maintained a ID class-conditional queue $|Q_y|$ for each class $y \\in \\mathcal{V}$ for continuous online estimation of $\\hat{\\mu}_c^t$ and $\\hat{\\Sigma}^t$ . The uncertainty regularization (Eq. (7)) is introduced in the middle of the training (i.e., at a certain starting epoch $E$ ).", + "bbox": [ + 76, + 522, + 468, + 630 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.2. Learning A Meta-representation", + "text_level": 1, + "bbox": [ + 76, + 638, + 362, + 655 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Outer-loop Training. In Section 4.1, the inner training task only involves updating the adapter $\\mathbf{h}_{\\Phi}$ and classifier $\\mathbf{c}_W$ while keeping the feature extractor $\\mathbf{f}_{\\Theta}$ fixed. In the outer loop, we target on updating $\\mathbf{f}_{\\Theta}$ corresponding to fixed $\\Phi$ , $W$ given in the inner tasks at each time $t \\in T_k'$ . Firstly, considering harnessing the knowledge transfer between continuous shifting distributions during time period $T_k'$ , we minimize the distribution discrepancy across the time period $T_k'$ : let $T_k' = \\{t_1', t_2', \\dots, t_l'\\}$ with $t_1' < t_2' < \\dots < t_l'$ , then", + "bbox": [ + 76, + 661, + 468, + 799 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {q r y}} = \\max _ {i \\in [ l - 1 ]} d _ {m k} ^ {2} \\left(\\mathbf {f} _ {\\Theta , \\Phi , W} \\left(S _ {\\mathrm {q r y}} ^ {t _ {i + 1} ^ {\\prime}}\\right), \\mathbf {f} _ {\\Theta , \\Phi , W} \\left(S _ {\\mathrm {q r y}} ^ {t _ {i} ^ {\\prime}}\\right)\\right), \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 91, + 806, + 468, + 837 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathbf{f}_{\\Theta ,\\Phi ,W}(S_{\\mathrm{qry}}^{t_i'}) = \\{\\mathbf{f}_{\\Theta ,\\Phi ,W}(\\mathbf{x}_{j,\\mathrm{qry}}^{t_i'})\\}_{j = 1}^{m't_i'}$ here we set $S_{\\mathrm{qry}}^{t_i'} = \\{\\mathbf{x}_{j,\\mathrm{qry}}^{t_i'}\\}_{j = 1}^{m't_i}$ . Intuitively, $\\mathcal{L}_{\\mathrm{qry}}$ estimates the discrepancies of continuously shifting distributions across the", + "bbox": [ + 76, + 845, + 468, + 901 + ], + "page_idx": 4 + }, + { + "type": "code", + "sub_type": "algorithm", + "code_caption": [ + "Algorithm 1. MOL in Training Process" + ], + "code_body": "Input: ID training samples $S$ and $\\{S^t\\}_{t\\in T_k}$ ; learning rates $\\alpha ,\\beta$ randomly initialized model $\\mathbf{f}_{W,\\Phi ,\\Theta} = \\mathbf{c}_W\\circ \\mathbf{h}_{\\Phi}\\circ \\mathbf{f}_{\\Theta}$ while not done do Randomly initialized adapter $\\mathbf{h}_{\\Phi}$ and classifier $\\mathbf{c}_W$ Randomly sample $T_{k}^{\\prime} = \\{t_{1}^{\\prime},t_{2}^{\\prime},\\dots,t_{l}^{\\prime}\\}$ from $T_{k}$ and sample support and query sets $\\mathbf{S}_{\\mathrm{spt}}$ and $\\mathbf{S}_{\\mathrm{qry}}$ from $\\{S^t\\}_{t\\in T_k'}$ for $i = 1$ to $l$ do Estimate $\\hat{\\mu}_c^{t_i}$ and $\\hat{\\Sigma}^{t_i}$ by using $S$ and Eq. (4); Sample virtual OOD samples $Z_{c}^{t_{i}}$ by Eq. (5); Compute $\\mathcal{L}^{t_i}$ using $S,S_{\\mathrm{spt}}^{t_i}$ and $Z_{c}^{t_{i}}$ by Eq. (7); Update parameters: $(\\Phi ,W)_{t_i + 1} = (\\Phi ,W)_{t_i} - \\alpha \\nabla \\mathcal{L}^{t_i}$ end for Compute $\\mathcal{L}_{\\mathrm{meta}}$ using $S$ and $\\mathbf{S}_{\\mathrm{qry}}$ by Eq. (9); Update parameters: $\\Theta = \\Theta -\\beta \\nabla \\mathcal{L}_{\\mathrm{meta}}$ end while Output: initial model $G_{\\gamma}$ $(\\mathbf{x};s,\\mathbf{f}_{\\Theta ,\\Phi ,W})$ by Eq. (1) meta-representation $\\mathbf{f}_{\\Theta}$", + "bbox": [ + 500, + 109, + 890, + 348 + ], + "page_idx": 4 + }, + { + "type": "code", + "sub_type": "algorithm", + "code_caption": [ + "Algorithm 2. MOL in Testing Process" + ], + "code_body": "Input: ID training samples $S$ and $\\{S^t\\}_{t\\in T_K^-}$ ; learning rates $\\alpha, \\beta$ ; meta-representation $\\mathbf{f}_{\\Theta}$ ; score function introduced in Eq. (2). while not done do \nRandomly initialized adapter $\\mathbf{h}_{\\Phi}$ and classifier $\\mathbf{c}_W$ ; \nfor $i = K$ to $N$ do \nEstimate $\\hat{\\mu}_c^{t_i}$ and $\\hat{\\Sigma}^{t_i}$ by using $S$ and Eq. (4); \nSample virtual OOD samples $Z_c^{t_i}$ by Eq. (5); \nCompute $\\mathcal{L}^{t_i}$ using $S$ , $S^{t_i}$ and $Z_c^{t_i}$ by Eq. (7); \nUpdate parameters: $(\\Phi, W)_{t_{i+1}} = (\\Phi, W)_{t_i} - \\alpha \\nabla \\mathcal{L}^{t_i}$ ; \nend for \nOutput: model $G_{\\gamma}(\\mathbf{x}; s, \\mathbf{f}_{\\Theta, \\Phi, W})$ by Eq. (1). end while", + "bbox": [ + 500, + 387, + 890, + 556 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "time period $T_{k}^{\\prime}$ . Then, the optimization issue in outer-loop training can be represented as follows:", + "bbox": [ + 500, + 566, + 890, + 597 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\min _ {\\Theta} \\mathcal {L} _ {\\text {m e t a}} = \\min _ {\\Theta} \\left[ \\mathcal {L} _ {\\text {c e}} + \\mathcal {L} _ {\\text {q r y}} \\right. \\\\ \\left. + \\frac {1}{\\left| T _ {k} ^ {\\prime} \\right|} \\sum_ {t \\in T _ {k} ^ {\\prime}} \\left(\\mathcal {L} _ {\\mathrm {d}} ^ {t} + \\lambda \\mathcal {L} _ {\\mathrm {o o d}} ^ {t}\\right) \\right], \\tag {9} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 526, + 607, + 890, + 671 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathcal{L}_{\\mathrm{d}}^{t}$ and $\\mathcal{L}_{\\mathrm{ood}}^{t}$ are computed by using the samples $S_{\\mathrm{qry}}^{t}$ in the query set $\\mathbf{S}_{\\mathrm{qry}}$ .", + "bbox": [ + 498, + 684, + 888, + 715 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In Eq. (9), the inner tasks (corresponding to $\\mathcal{L}_{\\mathrm{d}}^{t} + \\lambda \\mathcal{L}_{\\mathrm{odd}}^{t}$ ) across all time period $T_{k}^{\\prime}$ are fed as one input (corresponding to $\\sum_{t\\in T_k'}\\left(\\mathcal{L}_{\\mathrm{d}}^t +\\lambda \\mathcal{L}_{\\mathrm{odd}}^t\\right) / |T_k^{\\prime}|$ ) in the outer-loop training. Thus, we are able to learn a good initialization of meta-representation $\\Theta$ such that: when encountering a new distribution during testing, a few updating steps of $\\Phi ,W$ result in a good performance.", + "bbox": [ + 496, + 715, + 890, + 823 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Meta-testing. In the testing process, when exposed to previously unseen shifting distributions $D_{X_1Y_1}^t$ (where $t \\in T_K^{-}$ ), we only need to fine-tune the adapter $\\mathbf{h}_{\\Phi}$ and classifier $\\mathbf{c}_W$ on the new test samples $S^t$ (where $t \\in T_K^{-}$ ), while", + "bbox": [ + 496, + 838, + 890, + 902 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "19357", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "keeping the meta-representation $\\mathbf{f}_{\\Theta}$ fixed. This strategy enables fast adaptation by updating the lightweight classifier and adapter, which is useful for real-world online applications like self-driving agents. Furthermore, by incorporating the score function in Eq. (2), we can obtain an OOD detection model $g_{t}$ , while updating $\\mathbf{h}_{\\Phi}$ and $\\mathbf{c}_W$ at each time $t \\in T_K^-$ during the testing process.", + "bbox": [ + 75, + 90, + 472, + 198 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 76, + 212, + 209, + 229 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Adaptive OOD Benchmark Construction", + "text_level": 1, + "bbox": [ + 76, + 237, + 428, + 253 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "For CAOOD evaluation, we construct 3 benchmarks (e.g., using Rotation MNIST, Cifar Corruption datasets as ID datasets) derived from commonly used static OOD benchmarks (e.g., MNIST, Cifar). Rotation MNIST and Corruption datasets are frequently used in continuous domain adaptation [53, 56]. In practical applications, rotation can replicate shifts arising from camera positions, while corruptions mimic various weather conditions (e.g., fog, snow) and movements (e.g., motion). In CAOOD, we evaluate both ID accuracy and OOD detection effectiveness. Dataset details are provided in the Appendix.", + "bbox": [ + 75, + 262, + 468, + 428 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Rotation MNIST [5]. This dataset has MNIST digits with various rotations from $[0,180^{\\circ}]$ , and for each rotation, there are 60,000 training images. In our benchmark, we use Rotation MNIST (R-MNIST) as the ID training dataset and evaluate the OOD detection performance on Rotation NOTMNIST (R-NOTMNIST) and Rotation Cifar10bw (R-Cifar10bw). There are no semantics overlaps between the ID and OOD datasets.", + "bbox": [ + 75, + 428, + 468, + 547 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In our proposed MOL protocol, we consider images with rotation $0^{\\circ}$ as the labeled original training samples $S$ , and images from rotation $(0,180^{\\circ}]$ as continuously shifting distributions over the whole time period $(0,T]$ , i.e., $\\{S^t\\}_{t\\in T}$ . In meta-training, we use images from rotation $(0 - 60^{\\circ}]$ as $\\{S^t\\}_{t\\in T_k}$ , and randomly sample $\\mathbf{S}_{\\mathrm{spt}}$ , $\\mathbf{S}_{\\mathrm{qry}}$ of length 10. During meta-testing, we update our model online for rotation $\\{S_{120^{\\circ}},S_{126^{\\circ}},i\\dots S_{174^{\\circ}}\\}$ , i.e., $\\{S^t\\}_{T_K^-}$ and for each rotation, we only use 100 training samples for adaptation.", + "bbox": [ + 75, + 550, + 468, + 686 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Cifar10C. This dataset consists of 15 types of corruptions (e.g., fog, brightness, motion, noise) with each demonstrating 5 levels of severity. We use Cifar10C as the ID data and test on two near OOD datasets applying the same shifting distribution: TinyimageNetC, and Cifar100C. Following the OOD benchmark literature [63], we create TinyimageNetC from a subset of the Tinyimagenet [49] where 1207 images overlap semantic labels with Cifar10 are removed.", + "bbox": [ + 75, + 688, + 468, + 808 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In our protocol, we take clean images from Cifar10 as original training samples $S$ , and consider images with various corruptions from Cifar10C as samples come from shifting distributions. Specifically, we design the continuous shifting distributions by gradually changing the severity across all corruption types, for example:", + "bbox": [ + 75, + 810, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/addd95e4937ab6063ae83a0ef947a87c4eb012f4af761bc754b00fbec86c6d9e.jpg", + "table_caption": [ + "Table 1: OOD benchmarks used in our evaluation, including CAOD datasets, near OOD, and far OOD datasets." + ], + "table_footnote": [], + "table_body": "
ID DatasetCAOODNear OODFar OOD
R-MNISTR-NOTMNISTNOTMNISTCifar10bw
R-Cifar10bw
Cifar10CCifar100CCifar100Textures
TinyimagenetCTinyimageNetLSUN iSUN
Cifar100CCifar10CCifar10Textures
TinyimagenetCTinyimageNetLSUN iSUN
", + "bbox": [ + 501, + 130, + 890, + 273 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\underbrace {\\cdots , \\mathrm {C} _ {t - 1} ^ {5}} _ {\\text {t - 1 a n d b e f o r e}} \\rightarrow \\underbrace {\\mathrm {C} _ {t} ^ {1} , \\mathrm {C} _ {t} ^ {2} , \\mathrm {C} _ {t} ^ {3} , \\mathrm {C} _ {t} ^ {4} , \\mathrm {C} _ {t} ^ {5} , \\mathrm {C} _ {t} ^ {4} , \\mathrm {C} _ {t} ^ {3} , \\mathrm {C} _ {t} ^ {2} , \\mathrm {C} _ {t} ^ {1}} _ {\\text {c o r r u p t i o n t y p e t , c h a n g i n g g r a d u a l l y}} \\rightarrow \\underbrace {\\mathrm {C} _ {t + 1} ^ {1} , \\mathrm {C} _ {t + 1} ^ {2} , \\cdots} _ {\\text {t + 1 a n d o n}}\n$$\n", + "text_format": "latex", + "bbox": [ + 501, + 280, + 883, + 314 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In meta-training, we randomly sample $\\mathbf{S}_{\\mathrm{spt}}$ , $\\mathbf{S}_{\\mathrm{qry}}$ of length 10 (i.e., $|T_k'| = 10$ ), from the first 7 corruptions of 63 continuously shifting distributions, i.e., $\\{S^t\\}_{t \\in T_k}$ , $|T_k| = 63$ . In meta-testing, we adapt our model to a trajectory of length 10 that is randomly sampled from the last 7 corruptions and evaluate on unseen test images from the last 7 corruptions (i.e., frost, fog, brightness, contrast, elastic transform, pixelate, jpeg compression). Similarly, we only had access to 100 training samples in meta-testing.", + "bbox": [ + 498, + 315, + 890, + 450 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Cifar100C [16]. This dataset is a variant of Cifar10C by applying the same corruptions to Cifar100. We used Cifar100C as the ID dataset and two near OOD datasets with the same continuous shifting distributions: Cifar10C and TinyImageNetC. We re-create TinyImageNetC after 2505 images sharing the same classes with Cifar100 have been removed [63]. For the MOL protocol, we applied the same training and testing fashion as used in Cifar10C.", + "bbox": [ + 496, + 452, + 890, + 571 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Standard OOD Datasets. In addition, we evaluate our method's OOD detection performance on commonly used OOD datasets from a static distribution, including Cifar10 and Cifar100 [26], TinyImageNet [49], Textures [27], LSUN-Resize, LSUN-Crop [66], and iSUN [61]. Table 1 summarizes evaluated OOD detection benchmarks.", + "bbox": [ + 496, + 573, + 890, + 662 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.2. Baselines and Metrics", + "text_level": 1, + "bbox": [ + 500, + 676, + 702, + 691 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We compare our method with comprehensive OOD detection baselines including Maximum Softmax Probability [17], ODIN [32], Mahalanobis distance [29], energy score [34], Gram Metrics [45], Gradnorm [19], and the recent VOS [8], KNN [47] and LogitNorm [60]. To apply the above static OOD detection baselines in CAOOD, we use three different training/adapting schemes as follows.", + "bbox": [ + 496, + 700, + 890, + 806 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Direct Test. The model is trained on the labeled original training samples $S$ and then directly test on continuously shifting $\\{S^t\\}_{t\\in T_K^-}$ for OOD detection with no adaptation.", + "bbox": [ + 496, + 806, + 890, + 854 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Simple Adaptive. During training, the model is trained on the labeled original training samples $S$ . During testing, we finetune the classifier of the model to adapt to continuously", + "bbox": [ + 496, + 854, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "19358", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/c9b864585ababa09f49f1670459f643d1d5007cc0676882edee1fdcb7f5eaa65.jpg", + "table_caption": [ + "Table 2: Main Results on Rotation MNIST. $\\uparrow$ (or $\\downarrow$ ) indicates greater (or smaller) values are preferred. For each comparable method, we report results on Direct Test / Simple Adaptive / Domain Adaptation. Only Direct Test results are reported for Gram and KNN, only Direct Test and Simple Adaptive results are reported for VOS and LogitNorm. The bold and * represent the best and second best performance and the shadow part marks our method." + ], + "table_footnote": [], + "table_body": "
MethodRotation NOTMNISTRotation Cifar10bwAverageID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
MSP76.9 / 75.9 / 62.371.9 / 70.4 / 87.690.1 / 89.4 / 68.855.6 / 48.5 / 83.683.5 / 82.6 / 65.664.8 / 59.5 / 85.625.6 / 28.3 / 27.2
ODIN63.6 / 76.7 / 30.885.2 / 72.6 / 56.787.3 / 88.1 / 67.658.2 / 50.9 / 83.975.5 / 82.4 / 49.271.7 / 61.8 / 70.325.6 / 28.3 / 27.2
Mahalanobis61.2 / 75.4 / 32.986.1 / 75.1 / 56.989.3 / 90.1 / 66.758.1 / 49.5 / 80.875.3 / 82.8 / 49.872.1 / 62.3 / 68.925.6 / 28.4 / 27.7
Energy92.6 / 91.7 / 72.736.1 / 39.7 / 76.197.5 / 95.9 / 69.112.6 / 19.9 / 85.295.1 / 93.8 / 70.924.4 / 29.8 / 80.725.6 / 28.3 / 27.2
Gram96.1*10.698.9*4.6*97.5*7.625.6
VOS86.7 / 93.557.6 / 32.392.7 / 96.731.0 / 16.489.7 / 95.144.3 / 24.427.7 / 30.9
LogitNorm84.0 / 94.046.2 / 29.797.7 / 99.010.5 / 4.590.0 / 96.528.3 / 17.124.7 / 31.5*
KNN95.716.591.425.093.520.824.9
MOL96.513.9*98.9*9.297.711.5*35.6
", + "bbox": [ + 75, + 161, + 895, + 316 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/70ee12503978a90771cd0392fbb8f7f3259ad55c03093b9b18c8dbd2e0b52983.jpg", + "table_caption": [ + "Table 3: Main Results on Cifar10 corruption. $\\uparrow$ (or $\\downarrow$ ) indicates greater (or smaller) values are preferred. For each comparable method, we report results on Direct Test / Simple Adaptive / Domain Adaptation. Only Direct Test results are reported for Gram, Gradnorm, and KNN, only Direct Test and Simple Adaptive results are reported for VOS and LogitNorm. The bold and * represent the best performance and the shadow part marks our method." + ], + "table_footnote": [], + "table_body": "
MethodCifar100CTinyImagenetCAverageID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
MSP53.2 / 62.2 / 54.894.3 / 91.6 / 92.959.7 / 64.0 / 52.992.5 / 91.2 / 94.956.5 / 63.1 / 53.893.4 / 91.4 / 93.938.5 / 56.2 / 35.6
ODIN46.1 / 61.3 / 55.296.5 / 91.9 / 93.440.3 / 62.9 / 52.099.1 / 91.5 / 94.943.2 / 62.1 / 53.697.8 / 91.7 / 94.238.1 / 55.6 / 35.2
Mahalanobis46.8 / 63.6 / 55.196.7 / 91.3 / 93.447.0 / 66.0 / 53.698.1 / 90.6 / 93.946.9 / 64.8 / 54.497.4 / 90.9 / 93.738.5 / 56.2 / 35.6
Energy52.7 / 60.8 / 56.594.4 / 91.4 / 93.761.5 / 65.0 / 60.891.6 / 89.0 / 94.657.1 / 62.9 / 58.793.0 / 90.2 / 94.238.5 / 52.9 / 35.6
Gram55.289.766.582.560.986.1*38.1
Gradnorm29.597.241.396.535.496.938.5
VOS52.6 / 53.695.7 / 96.557.3 / 59.997.2 / 97.154.9 / 56.896.5 / 96.825.9 / 31.7
LogitNorm56.4 / 65.3*94.5 / 88.9*61.9 / 67.6*92.6 / 85.959.1 / 66.4*93.6 / 87.443.5 / 59.1*
KNN54.194.457.793.555.994.044.2
MOL69.786.371.485.6*70.685.964.1
", + "bbox": [ + 75, + 398, + 895, + 566 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "shifting $\\{S^t\\}_{t\\in T_K^-}$ dynamically and test their performance. Specifically, the classifier is updated using our proposed meta-testing strategy without virtual OOD generation and uncertainty regularization (i.e., by using Eq. 3).", + "bbox": [ + 75, + 590, + 468, + 654 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Domain Adaptation. The model is trained using classic domain adaptation techniques DAN [36]. Specifically, in the training process, we train the model offline by viewing $S$ as the source domain and all shifting training samples $\\{S^t\\}_{t \\in T_k}$ available as the target domain. During testing, we finetune the classifier of the model to adapt to continuously shifting $\\{S^t\\}_{t \\in T_K^-}$ dynamically and test their performance (Eq. (3)). By doing so the Domain Adaptation strategy violates the CAOD setting during training.", + "bbox": [ + 75, + 655, + 468, + 792 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Note that for Gram Metrics, Gradnorm, and KNN, only the Direct Test results are reported because their scoring functions are calculated based on feature representations across all layers, which demands a finetuning on the whole model during testing. For VOS and LogitNorm, only Direct Test and Simple Adaptive results are reported, as we found it difficult to train them with Domain Adaptation strategy.", + "bbox": [ + 75, + 794, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Evaluation Metrics. For OOD detection evaluation, we report 1) the area under the receiver operating characteristic curve (AUROC), which measures the model's capacity to distinguish ID and OOD samples based on varying thresholds of the predicted confidence scores; and 2) the false positive rate (FPR95) of OOD samples when the true positive rate of ID samples is fixed at $95\\%$ , which measures the percentage of OOD samples that are incorrectly classified as ID samples when the model's sensitivity to ID samples is high. For evaluating the ID classification, we report the commonly used accuracy.", + "bbox": [ + 496, + 590, + 893, + 758 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.3. Implementation Details", + "text_level": 1, + "bbox": [ + 500, + 770, + 718, + 787 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "On the R-MNIST dataset, we use LeNet as the backbone for all models. As for Cifar10C and Cifar100C datasets, we use WideResNet as the backbone. Note that in our method, the last fully connected layers of LeNet and WideResNet are removed for learning meta-representation during training. We set the uncertainty regularization balancing term $\\lambda$ as 0.015 for R-MNIST, and 0.1 for two CifarC datasets. The", + "bbox": [ + 496, + 794, + 893, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "19359", + "bbox": [ + 480, + 944, + 519, + 957 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/1b43db9760692adcb08b148002171b29068808e0acfeec78060f19d366e9b07d.jpg", + "table_caption": [ + "Table 4: Main Results on Cifar100 corruption. $\\uparrow$ (or $\\downarrow$ ) indicates greater (or smaller) values are preferred. For each comparable method, we report results on Direct Test / Simple Adaptive / Domain Adaptation (DA). Only Direct Test results are reported for Gram, Gradnorm, and KNN, only Direct Test and Simple Adaptive results are reported for VOS and LogitNorm. The bold and * represent the best performance and the shadow part marks our method." + ], + "table_footnote": [], + "table_body": "
MethodTinyImagenetCCifar10CAverageID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
MSP50.9 / 61.3 / 58.194.8 / 91.3 / 92.558.2 / 64.0 / 61.292.9 / 91.2 / 91.354.6 / 62.7* / 59.793.4 / 91.3 / 91.927.8 / 41.4 / 37.7
ODIN49.1 / 59.7 / 55.595.5 / 91.4 / 93.641.8 / 63.5 / 60.298.0 / 90.8* / 91.645.5 / 61.6 / 57.996.8 / 91.1* / 92.227.8 / 41.4 / 37.7
Mahalanobis48.597.140.499.044.598.127.8
Energy50.7 / 58.0 / 61.6*94.9 / 92.1 / 91.0*58.7 / 63.6* / 61.092.9 / 91.4 / 92.654.7 / 60.8 / 61.393.9 / 91.8 / 91.827.8 / 41.4 / 37.7
Gram47.195.949.695.648.495.827.8
VOS49.9 / 52.196.0 / 96.352.6 / 54.897.7 / 98.051.3 / 53.596.9 / 97.226.1 / 43.1*
LogitNorm53.0 / 58.394.1 / 92.258.8 / 63.193.2 / 91.955.9 / 60.793.7 / 92.023.4 / 38.5
KNN51.795.150.094.950.995.022.9
MOL69.488.763.189.066.388.957.4
", + "bbox": [ + 75, + 161, + 895, + 309 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/8e8faf2e11dddf91e67a7a1d03a739e9d2d19c88f7b9cb5dfdb2fcc91c478a9d.jpg", + "image_caption": [ + "Figure 3: The ID classification (a) and OOD detection performance (b-c) on R-MNIST benchmark over continuously shifting distributions. Our method achieved the best performance on all unseen distributions, i.e., the pink line." + ], + "image_footnote": [], + "bbox": [ + 158, + 328, + 344, + 450 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/405aa6acccfb98056eb25cd8223fc29799c06afdd5810045d20a0229624c4e55.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 395, + 328, + 578, + 450 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/a52959edae6a3bd0f9103c4d107ee82d0cc4beba612dcc2416c5c94d9e21a8f5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 630, + 328, + 812, + 450 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/8a4ce91824030830306b12ed95e1dcac9e38eaedd186cb36e0985a3eb2c64e8a.jpg", + "table_caption": [ + "Table 5: Average results over 10 randomly sampled trajectories on R-MNIST." + ], + "table_footnote": [], + "table_body": "
MethodR-NOTMNISTR-Cifar10bwID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
Fixed97.913.998.99.235.6
Sampled97.7 ±0.413.6 ±0.898.8 ±0.49.6 ±0.736.7 ±1.4
", + "bbox": [ + 76, + 554, + 468, + 621 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/9100439f2456c232115fdd10d2a15fb88fb3bc23b2c2c35923883efe71104546.jpg", + "table_caption": [ + "Table 6: Ablation study on R-MNIST, where w/o $\\mathcal{L}_{\\mathrm{ood}}$ and w/o $\\mathcal{L}_{\\mathrm{qry}}$ are variants trained without $\\mathcal{L}_{\\mathrm{ood}}$ and $\\mathcal{L}_{\\mathrm{qry}}$ . E indicates the adding point of $\\mathcal{L}_{\\mathrm{ood}}$ , e.g., $1/2$ indicates adding $\\mathcal{L}_{\\mathrm{ood}}$ halfway through training." + ], + "table_footnote": [], + "table_body": "
MethodR-NOTMNISTR-Cifar10bwID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
w/o Lood94.134.997.612.234.2
w/o Lqry93.935.196.914.332.2
E = 1/399.77.499.95.628.7
E = 1/298.010.499.18.730.1
E = 2/396.513.998.99.235.6
E = 4/595.315.595.216.335.9
", + "bbox": [ + 76, + 707, + 468, + 821 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "learning rates in inner/outer loops are set as 0.1/0.01 for R-MNIST, and 0.3/0.03 for two CIFarC datasets, respectively. We use SGD with 0.9 momentum and $5 \\times 10^{-4}$ weight decay. On each OOD benchmark, all methods are trained us-", + "bbox": [ + 75, + 839, + 470, + 902 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "ing the same backbones with the same number of epochs.", + "bbox": [ + 500, + 515, + 879, + 531 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4. Experimental Results", + "text_level": 1, + "bbox": [ + 500, + 542, + 702, + 559 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Results on R-MNIST. Table 2 summarizes the ID classification and OOD detection results on R-MNIST. The baseline results show that most existing static OOD detection methods cannot handle ID classification and OOD detection when test samples compass continuous distribution shifts. By using an alternate scheme when we fine-tune the model's classifier during testing (i.e., Simple Adaptive), the comparable methods improved around $2.7\\%$ in ID accuracy and reduced from $5.3\\%$ to $19.3\\%$ in FPR95 across all baselines. Such improvement endorses the dynamic adaptation of the OOD detection model when test samples come from continuously shifting distribution.", + "bbox": [ + 496, + 566, + 890, + 748 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "When examining the performance of the Domain Adaptation strategy, results show that ID accuracy improved over the Direct Test baselines, however, the OOD detection performance dropped heavily, from $17.9\\%$ to $26.3\\%$ across all methods in AUROC. In contrast to the Domain Adaptation strategy, our method obtained superior performance (ID accuracy: $35.6\\%$ , AUROC: $97.7\\%$ ) by respecting the continuous shifting characteristic of test distributions. Note that although Gram [45] obtained the best results in FPR95, their ID accuracy ( $10\\%$ lower than our method) questioned the", + "bbox": [ + 496, + 750, + 893, + 902 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "19360", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "reliability of the OOD detection performance in CAOOD.", + "bbox": [ + 76, + 90, + 467, + 104 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Results on Cifar Corruption. Table 3 and 4 show the OOD detection results on Cifar10C and Cifar100C. Results show that MOL achieved the best performance on both Cifar corruption benchmarks. On Cifar10C, we outperformed Direct Test, Simple Adaptive, and Domain Adaptation strategies by $25.6\\%$ , $7.9\\%$ , and $28.5\\%$ in ID classification respectively. For OOD detection, we outperformed most comparable methods and adaptation strategies. Our AUROC outperformed the second-best result (i.e., Simple Adaptive LogitNorm) by $4.2\\%$ . On Cifar100C, we improved the 3 adaptation strategies by $29.6\\%$ , $16.0\\%$ , and $19.7\\%$ respectively in ID accuracy, while maintaining the best average OOD detection performance when compared to all other methods. Note that in our reproduction, Gram shows a catastrophic OOD performance drop and Gradnorm obtained a $100\\%$ in FPR95 when tested on the Cifar100C benchmark, which indicates the instability of their scoring functions using gradients/features across all layers when applied in CAOOD.", + "bbox": [ + 75, + 106, + 467, + 378 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Performance on Continuously Shifting Distribution. Figure 3 shows the ID classification and AUROC over distributions on the Rotation MNIST benchmark. It is clear to see that the OOD detection performance of VOS and Energy decreased when the distribution continues to shift, while our method maintained a good OOD detection (i.e., the purple line). This further endorses our method's superiority in addressing the CAOOD problem by learning to quickly adapt to newly arriving test samples with shifting distributions.", + "bbox": [ + 75, + 380, + 467, + 515 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Discussion on the impact of Discretization. Theoretically, modeling in continuous time intervals requires infinite samples, making it unrealistic. As such discretization (using finite samples to simulate infinite samples) is a common way to address continuous domain adaptation [56, 2]. CIDA [53] employs closed intervals which uniformly sample finite time points from these intervals and obtain training data for each sampled time point. Following CIDA, instead of adapting to one fixed discretized trajectory, in meta-training, we adapt to randomly sampled trajectories (i.e., $\\mathbf{S}_{\\mathrm{spt}}, \\mathbf{S}_{\\mathrm{qry}}$ ) to approximate from $0^{\\circ}$ to $60^{\\circ}$ . To further evaluate the impact of discretization on detection accuracy, we evaluate our method on 10 randomly sampled trajectories during testing. Table 5 shows the average results suggesting that the detection performance remains stable across various trajectories (fixed and sampled).", + "bbox": [ + 75, + 517, + 467, + 758 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5.5. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 770, + 228, + 786 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "A brief ablation analysis is provided in Table 6. Firstly, we build a variant of our model without $\\mathcal{L}_{\\mathrm{ood}}$ by taking out the uncertainty regularization term $\\mathcal{L}_{\\mathrm{ood}}$ so it reduces to focus solely on continuous ID adaptation without synthesizing virtual OOD samples for uncertainty regularization. By doing so the ID accuracy slightly dropped by $1.4\\%$ while the OOD detection performance decreases noticeably (3.8% in", + "bbox": [ + 75, + 794, + 467, + 900 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "AUROC). Then, we conduct experiments on another variant without $\\mathcal{L}_{\\mathrm{qry}}$ without the constraint term on distribution discrepancy $\\mathcal{L}_{\\mathrm{qry}}$ , leading to performance drops on all ID accuracy, AUROC, and FPR95. This reflects that harnessing knowledge transfer between distributions is indispensable to the CAOD problem. Further, we studied the impact on starting point of uncertainty regularization during the whole training process. Results show that an earlier start resulted in a significant drop in ID accuracy while the OOD detection performance is good but meaningless. We suggest that a balance should be identified whenever the ID accuracy is prioritized. More ablations, experimental results, and comparisons about training/testing time refer to the Appendix.", + "bbox": [ + 496, + 90, + 890, + 287 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Conclusion and Future Works", + "text_level": 1, + "bbox": [ + 498, + 297, + 776, + 314 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "OOD detection has achieved great progress while facing challenges in real-world scenarios when test samples exhibit dynamic distribution shifting. Motivated by these challenges, we propose a novel and more realistic CAOD detection and develop an effective method of MOL in addressing this problem. To the best of our knowledge, we are the first to investigate OOD detection under continuous distribution shifts. Our proposal will motivate future works to pursue new methods in addressing real-world OOD detection under continuously shifting distributions.", + "bbox": [ + 496, + 323, + 890, + 474 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 500, + 486, + 596, + 502 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Abhijit Bendale and Terrance Boult. Towards open world recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1893-1902, 2015.", + "[2] Andreea Bobu, Eric Tzeng, Judy Hoffman, and Trevor Darryll. Adapting to continuously shifting domains. In International Conference on Learning Representations, 2018.", + "[3] Jiefeng Chen, Yixuan Li, Xi Wu, Yingyu Liang, and Somesh Jha. Atom: Robustifying out-of-distribution detection using outlier mining. In Machine Learning and Knowledge Discovery in Databases. Research Track: European Conference, ECML PKDD 2021, Bilbao, Spain, September 13-17, 2021, Proceedings, Part III 21, pages 430-445. Springer, 2021.", + "[4] Rui Dai, Yonggang Zhang, Zhen Fang, Bo Han, and Xinmei Tian. Moderately distributional exploration for domain generalization. International Conference on Machine Learning, 2023.", + "[5] Li Deng. The mnist database of handwritten digit images for machine learning research. IEEE Signal Processing Magazine, 29(6):141-142, 2012.", + "[6] Jiahua Dong, Yang Cong, Gan Sun, Zhen Fang, and Zhengming Ding. Where and how to transfer: Knowledge aggregation-induced transferability perception for unsupervised domain adaptation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 1(2):1-18, 2021.", + "[7] Jiahua Dong, Yang Cong, Gan Sun, Bineng Zhong, and Xiaowei Xu. What can be transferred: Unsupervised domain adaptation for endoscopic lesions segmentation. In" + ], + "bbox": [ + 506, + 511, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "19361", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4022-4031, June 2020.", + "[8] Xuefeng Du, Zhaoning Wang, Mu Cai, and Yixuan Li. Vos: Learning what you don't know by virtual outlier synthesis. In International Conference on Learning Representations, 2022.", + "[9] Thomas Elsken, Benedikt Staffler, Jan Hendrik Metzen, and Frank Hutter. Meta-learning of neural architectures for few-shot learning. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12365-12375, 2020.", + "[10] Zhen Fang, Yixuan Li, Jie Lu, Jiahua Dong, Bo Han, and Feng Liu. Is out-of-distribution detection learnable? Advances in Neural Information Processing Systems, 35:37199-37213, 2022.", + "[11] Zhen Fang, Jie Lu, Anjin Liu, Feng Liu, and Guangquan Zhang. Learning bounds for open-set learning. In International Conference on Machine Learning, pages 3122-3132. PMLR, 2021.", + "[12] Zhen Fang, Jie Lu, Feng Liu, and Guangquan Zhang. Semi-supervised heterogeneous domain adaptation: Theory and algorithms. IEEE Transactions on Pattern Analysis and Machine Intelligence, 45(1):1087-1105, 2023.", + "[13] Chelsea Finn, Pieter Abbeel, and Sergey Levine. Model-agnostic meta-learning for fast adaptation of deep networks. In International Conference on Machine Learning, pages 1126–1135. PMLR, 2017.", + "[14] Yaroslav Ganin, Evgeniya Ustinova, Hana Ajakan, Pascal Germain, Hugo Larochelle, François Laviolette, Mario Marchand, and Victor Lempitsky. Domain-adversarial training of neural networks. The journal of machine learning research, 17(1):2096-2030, 2016.", + "[15] Arthur Gretton, Karsten M Borgwardt, Malte J Rasch, Bernhard Scholkopf, and Alexander Smola. A kernel two-sample test. The Journal of Machine Learning Research, 13(1):723-773, 2012.", + "[16] Dan Hendrycks and Thomas Dietterich. Benchmarking neural network robustness to common corruptions and perturbations. In International Conference on Learning Representations, 2019.", + "[17] Dan Hendrycks and Kevin Gimpel. A baseline for detecting misclassified and out-of-distribution examples in neural networks. In International Conference on Learning Representations, 2016.", + "[18] Dan Hendrycks, Mantas Mazeika, and Thomas Dietterich. Deep anomaly detection with outlier exposure. In International Conference on Learning Representations, 2018.", + "[19] Rui Huang, Andrew Geng, and Yixuan Li. On the importance of gradients for detecting distributional shifts in the wild. Advances in Neural Information Processing Systems, 34:677-689, 2021.", + "[20] Rui Huang and Yixuan Li. Mos: Towards scaling out-of-distribution detection for large semantic space. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8710-8719, 2021.", + "[21] Xiaowei Huang, Daniel Kroening, Wenjie Ruan, James Sharp, Youcheng Sun, Emese Thamo, Min Wu, and Xinping" + ], + "bbox": [ + 78, + 92, + 467, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Yi. A survey of safety and trustworthiness of deep neural networks: Verification, testing, adversarial attack and defence, and interpretability. Computer Science Review, 37:100270, 2020.", + "[22] Conor Igoe, Youngseog Chung, Ian Char, and Jeff Schneider. How useful are gradients for ood detection really? arXiv preprint arXiv:2205.10439, 2022.", + "[23] Taewon Jeong and Heeyoung Kim. Ood-maml: Meta-learning for few-shot out-of-distribution detection and classification. Advances in Neural Information Processing Systems, 33:3907-3916, 2020.", + "[24] KJ Joseph, Salman Khan, Fahad Shahbaz Khan, and Vineeth N Balasubramanian. Towards open world object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5830-5840, 2021.", + "[25] KJ Joseph, Jathushan Rajasegaran, Salman Khan, Fahad Shahbaz Khan, and Vineeth N Balasubramanian. Incremental object detection via meta-learning. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(12):9209-9216, 2021.", + "[26] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images. 2009.", + "[27] Gustaf Kylberg. Kylberg texture dataset v. 1.0. 2011.", + "[28] Balaji Lakshminarayanan, Alexander Pritzel, and Charles Blundell. Simple and scalable predictive uncertainty estimation using deep ensembles. Advances in neural information processing systems, 30, 2017.", + "[29] Kimin Lee, Kibok Lee, Honglak Lee, and Jinwoo Shin. A simple unified framework for detecting out-of-distribution samples and adversarial attacks. Advances in neural information processing systems, 31, 2018.", + "[30] KIMIN LEE, Kibok Lee, Honglak Lee, and Jinwoo Shin. Training confidence-calibrated classifiers for detecting out-of-distribution samples. In International Conference on Learning Representations, 2018.", + "[31] Yi Li and Nuno Vasconcelos. Background data resampling for outlier-aware classification. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13218-13227, 2020.", + "[32] Shiyu Liang, Yixuan Li, and R Srikant. Enhancing the reliability of out-of-distribution image detection in neural networks. In International Conference on Learning Representations, 2018.", + "[33] Ziqian Lin, Sreya Dutta Roy, and Yixuan Li. Mood: Multi-level out-of-distribution detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 15313-15323, 2021.", + "[34] Weitang Liu, Xiaoyun Wang, John Owens, and Yixuan Li. Energy-based out-of-distribution detection. Advances in neural information processing systems, 33:21464-21475, 2020.", + "[35] Ziwei Liu, Zhongqi Miao, Xingang Pan, Xiaohang Zhan, Dahua Lin, Stella X Yu, and Boqing Gong. Open compound domain adaptation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12406-12415, 2020." + ], + "bbox": [ + 503, + 92, + 890, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "19362", + "bbox": [ + 480, + 945, + 519, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[36] Mingsheng Long, Yue Cao, Jianmin Wang, and Michael Jordan. Learning transferable features with deep adaptation networks. In International Conference on Machine Learning, pages 97-105. PMLR, 2015.", + "[37] Mingsheng Long, Han Zhu, Jianmin Wang, and Michael I Jordan. Deep transfer learning with joint adaptation networks. In International Conference on Machine Learning, pages 2208-2217. PMLR, 2017.", + "[38] Andrey Malinin and Mark Gales. Predictive uncertainty estimation via prior networks. Advances in neural information processing systems, 31, 2018.", + "[39] Yifei Ming, Ying Fan, and Yixuan Li. Poem: Out-of-distribution detection with posterior sampling. In International Conference on Machine Learning, pages 15650-15665. PMLR, 2022.", + "[40] Yifei Ming, Yiyou Sun, Ousmane Dia, and Yixuan Li. Cider: Exploiting hyperspherical embeddings for out-of-distribution detection. arXiv preprint arXiv:2203.04450, 2022.", + "[41] Yifei Ming, Hang Yin, and Yixuan Li. On the impact of spurious correlation for out-of-distribution detection. In Proceedings of the AAAI Conference on Artificial Intelligence, pages 10051-10059, 2022.", + "[42] Sinno Jialin Pan, Ivor W Tsang, James T Kwok, and Qiang Yang. Domain adaptation via transfer component analysis. IEEE Transactions on Neural Networks, 22(2):199-210, 2010.", + "[43] Juan-Manuel Perez-Rua, Xiatian Zhu, Timothy M Hospedales, and Tao Xiang. Incremental few-shot object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13846-13855, 2020.", + "[44] Shafin Rahman, Salman H Khan, and Fatih Porikli. Zero-shot object detection: Joint recognition and localization of novel concepts. International Journal of Computer Vision, 128:2979-2999, 2020.", + "[45] Chandramouli Shama Sastry and Sageev Oore. Detecting out-of-distribution examples with gram matrices. In International Conference on Machine Learning, pages 8491-8501. PMLR, 2020.", + "[46] Yiyou Sun, Chuan Guo, and Yixuan Li. React: Out-of-distribution detection with rectified activations. Advances in Neural Information Processing Systems, 34:144-157, 2021.", + "[47] Yiyou Sun, Yifei Ming, Xiaojin Zhu, and Yixuan Li. Out-of-distribution detection with deep nearest neighbors. In International Conference on Machine Learning, pages 20827-20840. PMLR, 2022.", + "[48] Jihoon Tack, Sangwoo Mo, Jongheon Jeong, and Jinwoo Shin. Csi: Novelty detection via contrastive learning on distributionally shifted instances. Advances in neural information processing systems, 33:11839-11852, 2020.", + "[49] Antonio Torralba, Rob Fergus, and William T Freeman. 80 million tiny images: A large data set for nonparametric object and scene recognition. IEEE Transactions on pattern analysis and machine intelligence, 30(11):1958-1970, 2008.", + "[50] Joost Van Amersfoort, Lewis Smith, Yee Whye Teh, and Yarin Gal. Uncertainty estimation using a single deep de" + ], + "bbox": [ + 78, + 90, + 468, + 900 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "terministic neural network. In International Conference on Machine Learning, pages 9690-9700. PMLR, 2020.", + "[51] Sachin Vernekar, Ashish Gaurav, Vahdat Abdelzad, Taylor Denouden, Rick Salay, and Krzysztof Czarnecki. Out-of-distribution detection in classifiers via generation. arXiv preprint arXiv:1910.04241, 2019.", + "[52] Ricardo Vilalta and Youssef Drissi. A perspective view and survey of meta-learning. Artificial intelligence review, 18:77-95, 2002.", + "[53] Hao Wang, Hao He, and Dina Katabi. Continuously indexed domain adaptation. In Proceedings of the 37th International Conference on Machine Learning, pages 9898-9907, 2020.", + "[54] Haoqi Wang, Zhizhong Li, Litong Feng, and Wayne Zhang. Vim: Out-of-distribution with virtual-logit matching. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4921-4930, 2022.", + "[55] Haotao Wang, Aston Zhang, Yi Zhu, Shuai Zheng, Mu Li, Alex J Smola, and Zhangyang Wang. Partial and asymmetric contrastive learning for out-of-distribution detection in long-tailed recognition. In International Conference on Machine Learning, pages 23446-23458. PMLR, 2022.", + "[56] Qin Wang, Olga Fink, Luc Van Gool, and Dengxin Dai. Continual test-time domain adaptation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7201-7211, 2022.", + "[57] Qizhou Wang, Feng Liu, Yonggang Zhang, Jing Zhang, Chen Gong, Tongliang Liu, and Bo Han. Watermarking for out-of-distribution detection. In Advances in Neural Information Processing Systems, 2022.", + "[58] Qizhou Wang, Junjie Ye, Feng Liu, Quanyu Dai, Marcus Kalander, Tongliang Liu, Jianye Hao, and Bo Han. Out-of-distribution detection with implicit outlier transformation. In International Conference on Learning Representations. OpenReview.net, 2023.", + "[59] Zitai Wang, Qianqian Xu, Zhiyong Yang, Yuan He, Xiaochun Cao, and Qingming Huang. Openauc: Towards auc-oriented open-set recognition. Advances in Neural Information Processing Systems, 35:25033-25045, 2022.", + "[60] Hongxin Wei, Renchunzi Xie, Hao Cheng, Lei Feng, Bo An, and Yixuan Li. Mitigating neural network overconfidence with logit normalization. In International Conference on Machine Learning, pages 23631-23644. PMLR, 2022.", + "[61] Jianxiong Xiao, James Hays, Krista A Ehinger, Aude Oliva, and Antonio Torralba. Sun database: Large-scale scene recognition from abbey to zoo. In 2010 IEEE computer society Conference on Computer Vision and Pattern Recognition, pages 3485-3492. IEEE, 2010.", + "[62] Jingkang Yang, Haoqi Wang, Litong Feng, Xiaopeng Yan, Huabin Zheng, Wayne Zhang, and Ziwei Liu. Semantically coherent out-of-distribution detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 8301-8309, 2021.", + "[63] Jingkang Yang, Pengyun Wang, Dejian Zou, Zitang Zhou, Kunyuan Ding, Wenxuan Peng, Haoqi Wang, Guangyao Chen, Bo Li, Yiyou Sun, et al. Openood: Benchmarking generalized out-of-distribution detection. Advances in Neural Information Processing Systems, 35:32598-32611, 2022." + ], + "bbox": [ + 503, + 92, + 890, + 900 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "19363", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[64] Jingkang Yang, Kaiyang Zhou, Yixuan Li, and Ziwei Liu. Generalized out-of-distribution detection: A survey. arXiv preprint arXiv:2110.11334, 2021.", + "[65] Jingkang Yang, Kaiyang Zhou, and Ziwei Liu. Full-spectrum out-of-distribution detection. arXiv preprint arXiv:2204.05306, 2022.", + "[66] Fisher Yu, Ari Seff, Yinda Zhang, Shuran Song, Thomas Funkhouser, and Jianxiong Xiao. Lsun: Construction of a large-scale image dataset using deep learning with humans in the loop. arXiv preprint arXiv:1506.03365, 2015.", + "[67] Li Zhong, Zhen Fang, Feng Liu, Bo Yuan, Guangquan Zhang, and Jie Lu. Bridging the theoretical bound and deep algorithms for open set domain adaptation. IEEE Transactions on Neural Networks and Learning Systems, 2021." + ], + "bbox": [ + 78, + 90, + 468, + 289 + ], + "page_idx": 11 + }, + { + "type": "page_number", + "text": "19364", + "bbox": [ + 480, + 945, + 517, + 955 + ], + "page_idx": 11 + } +] \ No newline at end of file diff --git a/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/06d792b4-9c42-4f8e-baa6-449a229309f7_model.json b/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/06d792b4-9c42-4f8e-baa6-449a229309f7_model.json new file mode 100644 index 0000000000000000000000000000000000000000..18a955a1469d55d5bda09faace9aee3c7258a1cf --- /dev/null +++ b/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/06d792b4-9c42-4f8e-baa6-449a229309f7_model.json @@ -0,0 +1,2578 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.158, + 0.131, + 0.815, + 0.154 + ], + "angle": 0, + "content": "Meta OOD Learning For Continuously Adaptive OOD Detection" + }, + { + "type": "text", + "bbox": [ + 0.268, + 0.18, + 0.703, + 0.2 + ], + "angle": 0, + "content": "Xinheng Wu† Jie Lu† Zhen Fang† Guangquan Zhang†" + }, + { + "type": "text", + "bbox": [ + 0.182, + 0.2, + 0.789, + 0.218 + ], + "angle": 0, + "content": "†Australian Artificial Intelligence Institute, University of Technology Sydney" + }, + { + "type": "text", + "bbox": [ + 0.137, + 0.22, + 0.839, + 0.235 + ], + "angle": 0, + "content": "Xinheng.Wu@student.uts.edu.au {Jie.Lu, Zhen.Fang, Guangquan.Zhang}@uts.edu.au*" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.269, + 0.314, + 0.285 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.301, + 0.474, + 0.71 + ], + "angle": 0, + "content": "Out-of-distribution (OOD) detection is crucial to modern deep learning applications by identifying and alerting about the OOD samples that should not be tested or used for making predictions. Current OOD detection methods have made significant progress when in-distribution (ID) and OOD samples are drawn from static distributions. However, this can be unrealistic when applied to real-world systems which often undergo continuous variations and shifts in ID and OOD distributions over time. Therefore, for an effective application in real-world systems, the development of OOD detection methods that can adapt to these dynamic and evolving distributions is essential. In this paper, we propose a novel and more realistic setting called continuously adaptive out-of-distribution (CAOD) detection which targets on developing an OOD detection model that enables dynamic and quick adaptation to a new arriving distribution, with insufficient ID samples during deployment time. To address CAOD, we develop meta OOD learning (MOL) by designing a learning-to-adapt diagram such that a good initialized OOD detection model is learned during the training process. In the testing process, MOL ensures OOD detection performance over shifting distributions by quickly adapting to new distributions with a few adaptations. Extensive experiments on several OOD benchmarks endorse the effectiveness of our method in preserving both ID classification accuracy and OOD detection performance on continuously shifting distributions." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.736, + 0.21, + 0.753 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.762, + 0.47, + 0.868 + ], + "angle": 0, + "content": "Out-of-distribution (OOD) detection is vital to modern deep learning (DL) applications in the real world, especially in safety-critical applications such as autonomous vehicle control [21], and medical areas [64]. This is because DL systems may make over-confident and incorrect predictions when encountering the out-of-distribution (OOD) samples, which possess semantic labels that are distinct from those" + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.272, + 0.895, + 0.462 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.47, + 0.895, + 0.531 + ], + "angle": 0, + "content": "Figure 1: Difference between existing static OOD detection and a more realistic scenario of Continuously Adaptive OOD Detection (Problem 1) when test samples come from continuously shifting distribution, i.e., Definition 1." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.552, + 0.895, + 0.704 + ], + "angle": 0, + "content": "of in-distribution (ID) samples [63]. To mitigate this issue, an important problem out-of-distribution detection has been proposed and studied extensively [10, 17]. In OOD detection, the classifier is required to perform accurate predictions on ID samples while simultaneously identifying OOD samples. Many representative methods either utilize outputs [17, 34], feature representations [29, 45], or gradients [19, 32] to enlarge the separations between ID and OOD samples, while others [18, 39] incorporate auxiliary OOD samples to regularize the deep models during training." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.896, + 0.902 + ], + "angle": 0, + "content": "Although OOD detection has achieved great progress, existing methods only focus on a simple scenario where ID and OOD samples are assumed to be drawn from static ID and OOD distributions. However, many real-world systems are changing dynamically and thus inherently exhibit continuous distribution shifts over time. Take a self-driving agent equipped with a scene recognition system as an example: in the real world, the surrounding environment (e.g., illumination, weather) may shift continuously on the road, such as from day to night, and from clean to foggy. Treating the arriving training and test samples as from static distributions may potentially harm the effectiveness of OOD detection, leading to the misclassification of distribution-shifted" + }, + { + "type": "page_footnote", + "bbox": [ + 0.078, + 0.875, + 0.47, + 0.901 + ], + "angle": 0, + "content": "*Corresponding to Jie Lu and Zhen Fang. The work is supported by the Australian Research Council under Discovery Grant DP200100700." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "19353" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.168 + ], + "angle": 0, + "content": "ID and OOD samples. Such scenarios highlight the limitations of current OOD detection methods when applied to continuously shifting distributions. Figure 1 highlights the difference between OOD detection on static distribution and when applying to continuously shifting distributions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.17, + 0.47, + 0.336 + ], + "angle": 0, + "content": "To tackle the continuously shifting scenarios in OOD detection, we propose a novel and realistic setting termed continuously adaptive out-of-distribution (CAOOD) detection, which targets on developing OOD detection method to 1) quickly adapt to the continuously shifting ID distributions and 2) detect the continuously shifting OOD samples over time. Note that during the deployment time, the ID samples may be insufficient during the adaptation process. Therefore, how to enable dynamic and quick adaptation with insufficient ID samples to achieve good OOD detection performance over time is core challenge of CAOOD detection." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.338, + 0.471, + 0.626 + ], + "angle": 0, + "content": "Inspired by domain adaptation [14, 6] and meta-learning [13], we develop a novel and effective CAOD detection method called meta out-of-distribution learning (MOL) to address the challenge in CAOD detection. To dynamically and quickly adapt to the continuously shifting ID samples, we leverage the learning-to-learn paradigm [52] of meta-learning which aims to learn an internal representation for quick adaptation to a new task. Specifically, by formulating adaptations to the continuous shifting ID samples as a variety of inner tasks, we design a meta-training procedure for learning to adapt explicitly. Further, to facilitate quick adaptation with insufficient ID samples, we propose to learn a meta-representation during training, which allows us to only update the light-weighted classifier during testing while keeping the meta-representation fixed. Additionally, considering OOD samples are unavailable in training, we propose to generate OOD samples based on the shifting ID feature representations. Lastly, the classifier is trained discriminatively based on both ID and virtual OOD samples." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.628, + 0.399, + 0.642 + ], + "angle": 0, + "content": "The contributions are summarized as follows:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.665, + 0.469, + 0.71 + ], + "angle": 0, + "content": "- We propose a more realistic OOD detection setting called CAOD detection to promote the applications of OOD detection techniques in real-world scenarios." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.73, + 0.469, + 0.79 + ], + "angle": 0, + "content": "- We develop technologies based on meta-learning and domain adaptation to quickly adapt to the continuously shifting ID distributions. With these technologies, MOL is proposed to address CAOD detection." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.811, + 0.469, + 0.901 + ], + "angle": 0, + "content": "- We conduct extensive experiments comparing MOL with competitive OOD detection methods using various fine-tuning/adaptation strategies on 114 CAOOD detection tasks. Experiments show that MOL achieves the best performance for both ID classification and OOD detection in continuously shifting distributions." + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.665, + 0.469, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.09, + 0.642, + 0.107 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.115, + 0.892, + 0.447 + ], + "angle": 0, + "content": "Out-of-distribution Detection methods are mainly post-hoc based adopting different scoring functions based on either logit outputs [17, 32, 34, 46, 28, 20], feature representations [45, 29, 33, 54, 47], or gradients [32, 19, 22]. These methods enjoy good applicability when deployed as they can be easily integrated into a pre-trained model without retraining. Other works utilize contrastive learning [48, 47, 55], specifically designed loss functions [60, 38, 40]. However, these methods often require sophisticated score functions but may not necessarily outperform post-hoc methods in general as noted by [63]. Another line of OOD detection methods focus on regularizing the training of classifier using either auxiliary OOD datasets or generated fake OOD samples [18, 30, 34]. These works study sampling strategies [39, 3, 31], OOD samples generation approaches [30, 51, 8], and uncertainty regularization mechanisms [50]. In addition to above strategies, other strategies have also been explored. For example, to overcome the intrinsic inconsistency of prior metrics by aggregating both the known and unknown class performance in a single performance curve, [59] propose a novel OOD detection metric named OpenAUC as the final objective function to learn OOD detector." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.449, + 0.892, + 0.658 + ], + "angle": 0, + "content": "Above OOD detection methods neglect inevitable distribution shifts in test data over time in real-world applications. Very few OOD detection works consider such shift: one work [62] used a large unlabeled dataset containing ID samples aiming to encourage ID semantic information modeling while being robust to covariate shift. Another work [65] considers explicitly promotes the generalization capacity of the OOD detector when being evaluated on covariate-shifted ID data. Recent work [41] discovers that environmental-related features (e.g., backgrounds) significantly worsen existing OOD detection performance. These early attempts highlight existing OOD detection methods are prone to distribution shifts and consequently inadequate for realistic scenarios, which motivates our research." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.66, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Domain Adaptation (DA) aims to adapt machine learning models to unseen and different distributions [12, 64, 67, 7]. In complementary to OOD detection, DA improves models' generalization ability to covariate shift when test data share the same label set as training [35, 4]. Most existing DA methods focus on matching discrete source and target domains leveraging domain statistics [42], distance-based loss functions [37], and adversarial training [14]. Recently, different methods are developed to perform continuous domain adaptation when the target domain shifts smoothly over time [2, 53, 56]. Continuous domain adaptation is related to our problem but it does not follow an open-world assumption where test data may contain OOD samples that do not belong to the training label set. In this paper, we address a more challenging open-world learning scenario, OOD detection under continuous shifting distributions." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19354" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.244 + ], + "angle": 0, + "content": "Open World Recognition aims to incrementally learn new information without forgetting in an open world [24, 1, 11]. This problem concentrates on zero-shot learning [44], mitigating catastrophic forgetting [25], and incremental learning [43], where unknown samples can be progressively labeled as inputs. This is different from our focus on learning an open-world classifier that can quickly adapt to continuously shifted domains online while maintaining both ID and OOD detection performance. Additional literature on the topic of meta-learning is included in the Appendix." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.259, + 0.35, + 0.276 + ], + "angle": 0, + "content": "3. Problem Setup and Notations" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.284, + 0.47, + 0.408 + ], + "angle": 0, + "content": "OD Detection. Let \\(\\mathcal{X}\\) denote the feature space, \\(\\mathcal{Y} = [C]\\) be the label space. We consider the ID distribution \\(D_{X_1Y_1}\\) as a joint distribution defined over \\(\\mathcal{X}\\times \\mathcal{Y}\\), where \\(X_{\\mathrm{I}}\\) and \\(Y_{\\mathrm{I}}\\) are random variables whose outputs are from spaces \\(\\mathcal{X}\\) and \\(\\mathcal{Y}\\). Given a set of \\(n\\) samples drawn i.i.d. from the ID distribution called ID data, \\(S = \\{(\\mathbf{x}_j,y_j)\\}_{j = 1}^n\\sim D_{X_1Y_1}\\). A classic classification model \\(\\mathbf{f}:\\mathcal{X}\\to \\mathbb{R}^{C}\\), is trained on the training set \\(S\\), to predict the label of an input test data [10]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.408, + 0.47, + 0.529 + ], + "angle": 0, + "content": "During the test time of OOD detection, the test samples contain some unknown OOD samples drawn from an OOD distribution \\(D_{X_0Y_0}\\), where \\(X_0\\) is a random variable from \\(\\mathcal{X}\\), but \\(Y_0\\) is a random variable whose outputs do not belong to \\(\\mathcal{Y}\\), i.e., \\(Y_0 \\notin \\mathcal{Y}\\). The classical OOD detection methods aim to design an effective score function \\(s(\\cdot; \\mathbf{f}): \\mathcal{X} \\to \\mathbb{R}\\) [32, 29, 34] and train a corresponding model \\(\\mathbf{f}\\) by ID samples \\(S\\) such that the following OOD detector" + }, + { + "type": "equation", + "bbox": [ + 0.141, + 0.543, + 0.47, + 0.575 + ], + "angle": 0, + "content": "\\[\nG _ {\\gamma} (\\mathbf {x}; s, \\mathbf {f}) = \\left\\{ \\begin{array}{l l} \\text {I D} & \\text {i f} s (\\mathbf {x}; \\mathbf {f}) \\geq \\gamma \\\\ \\text {O O D} & \\text {i f} s (\\mathbf {x}; \\mathbf {f}) < \\gamma \\end{array} \\right. \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.584, + 0.47, + 0.645 + ], + "angle": 0, + "content": "where \\(\\gamma\\) is a threshold can distinguish ID and OOD samples accurately. In this paper, we select \\(\\gamma\\) when \\(95\\%\\) ID data is correctly classified [63, 58, 57], and use energy score [34] as the scoring function to design our OOD detector, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.175, + 0.659, + 0.47, + 0.699 + ], + "angle": 0, + "content": "\\[\ns (\\mathbf {x}; \\mathbf {f}) = \\log \\sum_ {l = 1} ^ {C} \\exp (f _ {l} (\\mathbf {x})) \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.708, + 0.357, + 0.724 + ], + "angle": 0, + "content": "where \\(f_{l}(\\mathbf{x})\\) is the \\(l\\)-th coordinate of \\(\\mathbf{f}(\\mathbf{x})\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.739, + 0.47, + 0.875 + ], + "angle": 0, + "content": "Continuously Adaptive OOD Detection. To tackle more realistic scenarios that the ID and OOD samples are from continuously shifting distributions over a discrete time period \\( T = \\{t_1, t_2, \\dots, t_N\\} \\), which satisfies that \\( 0 < t_1 < t_2 < \\dots < t_N \\). We also set \\( T_k = \\{t_1, t_2, \\dots, t_k\\} \\) and set \\( T_K^- = \\{t_K, t_{K+1}, \\dots, t_N\\} \\), where \\( 1 \\leq k < K \\leq N \\). It is clear that \\( T_k \\cup T_K^- \\subset T \\) and \\( T_k \\cap T_K^- = \\emptyset \\). Next, the definition of continuously shifting ID and OOD distributions is given in Definition 1." + }, + { + "type": "page_footnote", + "bbox": [ + 0.095, + 0.887, + 0.468, + 0.902 + ], + "angle": 0, + "content": "1We use [N] to represent set {1,..., N}. Therefore, \\([C] = \\{1,\\dots,C\\}\\)." + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.091, + 0.885, + 0.221 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.234, + 0.892, + 0.3 + ], + "angle": 0, + "content": "Figure 2: A heuristic illustration CAOD problem. The target is to train an OOD detection model \\( g_{0} \\) using S, \\( \\{S^t\\}_{t \\in T_k} \\) so it can obtain good OOD detection performance on unseen shifting samples \\( \\{S^t\\}_{t \\in T_K^-} \\) by quick adaptation." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.313, + 0.892, + 0.376 + ], + "angle": 0, + "content": "Definition 1 (Continuously Shifting Distributions.) Let \\(D_{X_1Y_1}^t\\) and \\(D_{X_0Y_0}^t\\) are \\(ID\\) and OOD joint distributions at time \\(t \\in T\\). We say \\(D_{X_1Y_1}^t, D_{X_0Y_0}^t\\) are continuously shifting \\(ID\\) and OOD distributions, if for any \\(i \\in [N-1]\\)," + }, + { + "type": "equation", + "bbox": [ + 0.619, + 0.385, + 0.772, + 0.429 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} d \\left(D _ {X _ {1} Y _ {1}} ^ {t _ {i}}, D _ {X _ {1} Y _ {1}} ^ {t _ {i + 1}}\\right) < \\epsilon , \\\\ d (D _ {X _ {\\mathrm {O}}} ^ {t _ {i}}, D _ {X _ {\\mathrm {O}}} ^ {t _ {i + 1}}) < \\epsilon , \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.438, + 0.886, + 0.453 + ], + "angle": 0, + "content": "where \\(d(\\cdot, \\cdot)\\) is a distribution metric and \\(\\epsilon\\) is a small value." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.465, + 0.892, + 0.556 + ], + "angle": 0, + "content": "In Definition 1, the small value \\(\\epsilon\\) is used to estimate the gradual variations and quantify the continuity of continuously shifting ID and OOD distributions. We note here that distribution shift over time can be significant as it gradually accumulates. Next, we give the definition of continuously adaptive OOD detection." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.568, + 0.868, + 0.583 + ], + "angle": 0, + "content": "Problem 1 (Continuously Adaptive OOD Detection.)" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.583, + 0.892, + 0.63 + ], + "angle": 0, + "content": "Let \\( D_{X_{\\mathrm{I}}Y_{\\mathrm{I}}}^{t} \\) and \\( D_{X_{\\mathrm{O}}Y_{\\mathrm{O}}}^{t} \\) be the continuously shifting ID and OOD distributions over time period \\( T \\) and let \\( D_{X_{\\mathrm{I}}Y_{\\mathrm{I}}} \\) be the original ID distribution. Given sets of samples" + }, + { + "type": "equation", + "bbox": [ + 0.561, + 0.64, + 0.864, + 0.657 + ], + "angle": 0, + "content": "\\[\nS = \\left\\{\\left(\\mathbf {x} _ {1}, y _ {1}\\right), \\dots , \\left(\\mathbf {x} _ {n}, y _ {n}\\right) \\right\\} \\sim D _ {X _ {1} Y _ {1}}, i. i. d.\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.528, + 0.659, + 0.865, + 0.677 + ], + "angle": 0, + "content": "\\[\nS ^ {t} = \\left\\{\\mathbf {x} _ {1} ^ {t}, \\dots , \\mathbf {x} _ {n} ^ {t} \\right\\} \\sim D _ {X _ {1}} ^ {t}, i. i. d., f o r e a c h t \\in T\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.689, + 0.892, + 0.83 + ], + "angle": 0, + "content": "with \\( n^t \\ll n \\) if \\( t \\in T_K^- \\), the aim of continuously adaptive OOD detection is to train an initial OOD detection model \\( g_0 \\) using \\( S \\), \\( \\{S^t\\}_{t \\in T_k} \\), and to quickly update the model \\( g_{t_i} \\) (at each time \\( t_i \\in T_K^- = \\{t_K, t_{K+1}, \\dots, t_N\\} \\)) based on the previous model \\( g_{t_{i-1}} \\) (\\( g_0 \\) is the initial model, i.e., \\( g_{t_{K-1}} = g_0 \\)) using \\( S \\), \\( S^{t_i} \\). Such that for any test sample \\( \\mathbf{x} \\in \\{S^t\\}_{t \\in T_K^-} \\): 1) if \\( \\mathbf{x} \\) is from ID distribution \\( D_{X_1}^t \\), \\( g_{t_N} \\) classifies \\( \\mathbf{x} \\) into correct ID label; and 2) if \\( \\mathbf{x} \\) is from OOD distribution \\( D_{X_0}^t \\), \\( g_{t_N} \\) detects \\( \\mathbf{x} \\) as OOD." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.84, + 0.892, + 0.902 + ], + "angle": 0, + "content": "A heuristic illustration of the CAOD problem is provided in Figure 2. The key challenge of Problem 1 is to quickly adapt to new ID distribution \\( D_{X_1}^{t_i} \\) using insufficient ID samples \\( S^{t_i} \\) at time \\( t_i \\). To achieve satisfied performance" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19355" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.152 + ], + "angle": 0, + "content": "across time period \\( T_{K}^{-} \\), a good initial OOD detection model \\( g_{0} \\) is indispensable for effective adaptation. In Section 4, we illustrate the proposed MOL method and detail how to obtain the initial model \\( g_{0} \\) during the training procedure." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.153, + 0.471, + 0.322 + ], + "angle": 0, + "content": "Notations. To facilitate better comprehension, we introduce some necessary notations. To learn a good initial OOD detection model \\( g_{0} \\), we mainly use meta-learning techniques. Following the meta-training procedure [13], we need to sample a support set \\( \\mathbf{S}_{\\mathrm{spt}} = \\{S_{\\mathrm{spt}}^{t}\\}_{t\\in T_{k}^{\\prime}} \\) from \\( \\{S^t\\}_{t\\in T_k} \\) where \\( T_{k}^{\\prime}\\subset T_{k} \\) and \\( S_{\\mathrm{spt}}^{t}\\subset S^{t} \\). We also need to sample a query set \\( \\mathbf{S}_{\\mathrm{qry}} = \\{S_{\\mathrm{qry}}^{t}\\}_{t\\in T_{k}^{\\prime}} \\) from \\( \\{S^t\\}_{t\\in T_k} \\), where \\( S_{\\mathrm{qry}}^{t}\\subset S^{t} \\). Further, we set \\( \\mathbf{f}_{\\Theta} \\) to be the feature extractor, set \\( \\mathbf{h}_{\\Phi} \\) to be the adapter, and set \\( \\mathbf{c}_W \\) to be the classifier, where \\( \\Theta ,\\Phi \\) and \\( W \\) are the parameters. Then the classification model \\( \\mathbf{f} \\) can be expressed as a function composition:" + }, + { + "type": "equation", + "bbox": [ + 0.189, + 0.332, + 0.357, + 0.348 + ], + "angle": 0, + "content": "\\[\n\\mathbf {f} _ {W, \\Phi , \\Theta} = \\mathbf {c} _ {W} \\circ \\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta}.\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.358, + 0.469, + 0.389 + ], + "angle": 0, + "content": "Lastly, the OOD detection model \\(G_{\\gamma}\\) can be obtained via the score function \\(s(\\cdot ;\\mathbf{f}_{W,\\Phi ,\\Theta})\\) as shown in Eqs. 1 and 2." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.39, + 0.469, + 0.436 + ], + "angle": 0, + "content": "To adapt the shifting distributions, we mainly utilize the maximum mean discrepancy (MMD) [15], which are introduced in following: given samples \\(\\{\\mathbf{x}_i\\}_{i=1}^n\\) and \\(\\{\\mathbf{x}_j'\\}_{j=1}^m\\)," + }, + { + "type": "equation", + "bbox": [ + 0.15, + 0.447, + 0.398, + 0.506 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} d _ {k} (\\{\\mathbf {x} _ {i} \\} _ {i = 1} ^ {n}, \\{\\mathbf {x} _ {j} ^ {\\prime} \\} _ {j = 1} ^ {m}) \\\\ = \\left\\| \\frac {1}{n} \\sum_ {i = 1} ^ {n} \\phi_ {k} (\\mathbf {x} _ {i}) - \\frac {1}{m} \\sum_ {i = 1} ^ {m} \\phi_ {k} (\\mathbf {x} _ {j}) \\right\\| _ {k}, \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.515, + 0.469, + 0.56 + ], + "angle": 0, + "content": "where \\(k\\) is the kernel and \\(\\phi_{k}\\) is the kernel feature map. To further improve the adaptive performance, in this work, we use the multi-kernel MMD \\(d_{mk}\\), which is shown in [36]." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.574, + 0.212, + 0.59 + ], + "angle": 0, + "content": "4. Methodology" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.599, + 0.469, + 0.748 + ], + "angle": 0, + "content": "It is important to recognize that while the number of test samples \\( S^t (t \\in T_K^-) \\) may be limited during deployment, we often have access to a satisfactory number of labeled training samples \\( S \\) as well as unlabeled samples \\( \\{S^t\\}_{t \\in T_k} \\) that can be used to simulate distribution shifts that may occur during deployment. This motivates us to learn a well-designed initial OOD detection model \\( g_0 \\) that utilizes both labeled training samples \\( S \\) and unlabeled samples \\( \\{S^t\\}_{t \\in T_k} \\) to effectively adapt to the shifting test samples \\( S^t (t \\in T_K^-) \\) as defined in Problem 1." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.469, + 0.9 + ], + "angle": 0, + "content": "To develop an effective initial OOD detection model \\( g_0 \\), we consider learning an internal meta-representation that enables efficient adaptation to the new distributions in Problem 1. Additionally, note that OOD samples are unavailable during the training process, we utilize the virtual OOD synthesize [8] techniques to generate reliable-virtual OOD samples. The virtual OOD samples emulate real OOD samples and thus enable the classifier to be trained with an additional uncertainty regularization term that incorporates both ID and virtual OOD information." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.364 + ], + "angle": 0, + "content": "An effective strategy of learning \\( g_{0} \\) is to draw upon the experience of meta-learning [9, 52]. Originally proposed for addressing few-shot learning [9, 23], meta-learning involves utilizing fast adaptation on a small number of samples. By using meta-learning [13], we can efficiently adapt the initial model to new distributions encountered during deployment. Specifically, a meta-training process is explicitly designed for learning-to-adapt by viewing the adaptation to each time \\( t \\in T_k' \\) for OOD detection as the inner tasks, thus dynamic adaptations across all time periods \\( T_k' \\) can be regarded as one input for the outer-loop training process. Concretely, we can train the classifier by considering both ID adaptation and OOD uncertainty regularization. In the outer loop, we update the model with respect to many inner tasks across all time periods \\( T_k' \\). We detail the inner learning tasks and outer-loop meta-training process in Sections 4.1 and 4.2. The entire procedures of the proposed MOL method are shown in Algorithms 1 and 2." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.375, + 0.771, + 0.391 + ], + "angle": 0, + "content": "4.1. Inner Learning Task for MOL" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.399, + 0.892, + 0.476 + ], + "angle": 0, + "content": "ID Adaptation. In the inner task, we firstly train the adapter \\(\\mathbf{h}_{\\Phi}\\) and classifier \\(\\mathbf{c}_W\\) to adapt to current ID distribution at time point \\(t \\in T_k'\\) using support set \\(\\mathbf{S}_{\\mathrm{spt}}\\). Specifically, given a cross-entropy loss \\(\\ell_{\\mathrm{ce}}\\) and multi-kernel MMD \\(d_{mk}\\), we minimize the following objective." + }, + { + "type": "equation", + "bbox": [ + 0.511, + 0.489, + 0.891, + 0.551 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\min _ {\\Phi , W} \\left[ \\mathcal {L} _ {\\mathrm {c e}} + \\mathcal {L} _ {\\mathrm {d}} ^ {t} \\right] = \\min _ {\\Phi , W} \\left[ \\frac {1}{n} \\sum_ {i = 1} ^ {n} \\ell_ {\\mathrm {c e}} \\left(\\mathbf {f} _ {\\Theta , \\Phi , W} \\left(\\mathbf {x} _ {i}\\right), y _ {i}\\right) \\right. \\tag {3} \\\\ \\left. \\right. + d _ {m k} ^ {2} \\big (\\{\\mathbf {f} _ {\\Theta , \\Phi , W} (\\mathbf {x} _ {i}) \\} _ {i = 1} ^ {n}, \\{\\mathbf {f} _ {\\Theta , \\Phi , W} (\\mathbf {x} _ {j, \\mathrm {s p t}} ^ {t}) \\} _ {j = 1} ^ {m ^ {t}} \\big) \\big ], \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.565, + 0.892, + 0.612 + ], + "angle": 0, + "content": "where \\(\\{\\mathbf{x}_{j,\\mathrm{spt}}^t\\}_{j = 1}^m = S_{\\mathrm{spt}}^t\\) . Then at each time \\(t\\in T_k^\\prime\\) , we estimate the empirical mean and covariance of training samples \\(S\\) for each class \\(c\\in \\mathcal{V}\\) using \\(\\mathbf{h}_{\\Phi}\\circ \\mathbf{f}_{\\Theta}\\) [29]," + }, + { + "type": "equation", + "bbox": [ + 0.525, + 0.624, + 0.891, + 0.667 + ], + "angle": 0, + "content": "\\[\n\\hat {\\boldsymbol {\\mu}} _ {c} ^ {t} = \\frac {1}{n _ {c}} \\sum_ {i: y _ {i} = c} \\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta} \\left(\\mathbf {x} _ {i}\\right), \\quad \\hat {\\boldsymbol {\\Sigma}} ^ {t} = \\frac {1}{n} \\sum_ {c = 1} ^ {C} \\hat {\\boldsymbol {\\Sigma}} _ {c} ^ {t}, \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.68, + 0.85, + 0.695 + ], + "angle": 0, + "content": "where \\(n_c\\) is the number of samples \\(S\\) for class \\(c\\), and" + }, + { + "type": "equation", + "bbox": [ + 0.5, + 0.708, + 0.878, + 0.748 + ], + "angle": 0, + "content": "\\[\n\\hat {\\boldsymbol {\\Sigma}} _ {c} ^ {t} = \\sum_ {i: y _ {i} = c} ^ {n} \\left(\\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta} \\left(\\mathbf {x} _ {i}\\right) - \\hat {\\boldsymbol {\\mu}} _ {c} ^ {t}\\right) \\left(\\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta} \\left(\\mathbf {x} _ {i}\\right) - \\hat {\\boldsymbol {\\mu}} _ {c} ^ {t}\\right) ^ {\\top}.\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.761, + 0.891, + 0.791 + ], + "angle": 0, + "content": "Note that the adapter \\(\\mathbf{h}_{\\Phi}\\) is updated by the training objective in Eq. (3) at each time \\(t\\in T_k^{\\prime}\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.792, + 0.892, + 0.867 + ], + "angle": 0, + "content": "Virtual OOD Generation. We generate virtual OOD samples based on the updated ID features \\(\\mathbf{h}_{\\Phi} \\circ \\mathbf{f}_{\\Theta}\\) at each time \\(t \\in T_k'\\). Motivated by [8, 29], we also assume that adapted class-conditional ID distribution \\(D_{\\mathbf{h}_{\\Phi} \\circ \\mathbf{f}_{\\Theta}(X_{\\mathrm{I}}) | Y_{\\mathrm{I}} = c}^{t}\\) is similar to a multivariate Gaussian distribution, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.584, + 0.88, + 0.808, + 0.905 + ], + "angle": 0, + "content": "\\[\nD _ {\\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta} (X _ {\\mathrm {I}}) | Y _ {\\mathrm {I}} = c} ^ {t} \\approx \\mathcal {N} \\left(\\hat {\\mu} _ {c} ^ {t}, \\hat {\\Sigma} ^ {t}\\right),\n\\]" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19356" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.091, + 0.47, + 0.141 + ], + "angle": 0, + "content": "which implies that we can sample virtual OOD samples \\(Z_{c}^{t}\\) at the adapted feature space \\(\\mathcal{Z} = \\mathbf{h}_{\\Phi}\\circ \\mathbf{f}_{\\Theta}(\\mathcal{X})\\subset \\mathbb{R}^{\\tilde{d}}\\) to each class \\(c\\) in the \\(\\delta\\)-likelihood region, i.e., \\(Z_{c}^{t}\\) is sampled from" + }, + { + "type": "equation", + "bbox": [ + 0.093, + 0.147, + 0.47, + 0.181 + ], + "angle": 0, + "content": "\\[\n\\left\\{\\mathbf {z} _ {c} ^ {t} \\mid \\frac {A}{| \\hat {\\boldsymbol {\\Sigma}} | ^ {1 / 2}} \\exp \\left(\\left(\\mathbf {z} _ {c} ^ {t} - \\hat {\\boldsymbol {\\mu}} _ {c} ^ {t}\\right) \\hat {\\boldsymbol {\\Sigma}} ^ {- 1} \\left(\\mathbf {z} _ {c} ^ {t} - \\hat {\\boldsymbol {\\mu}} _ {c} ^ {t}\\right)\\right) < \\delta \\right\\}, \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.191, + 0.469, + 0.239 + ], + "angle": 0, + "content": "where \\(A = 1 / (2\\pi)^{\\tilde{d} /2}\\) and \\(\\delta\\) is a small constant to ensure that the sampled OOD samples \\(Z_{c}^{t}\\) are near the estimated class boundary in the adapted feature space \\(\\mathcal{Z}\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.24, + 0.47, + 0.346 + ], + "angle": 0, + "content": "Inner Uncertainty Regularization. By the above steps, at each time \\( t \\in T_k' \\), we obtained the adapting ID information and the virtual OOD samples at the adapted feature space \\( \\mathcal{Z} \\). Now we add an extra regularization term such that the classifier \\( \\mathbf{c}_W \\) can classify the adapted ID samples and virtual OOD samples in the adapted feature space \\( \\mathcal{Z} \\). Specifically, the regularization term [8] is shown in following," + }, + { + "type": "equation", + "bbox": [ + 0.116, + 0.354, + 0.469, + 0.433 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {L} _ {\\mathrm {o o d}} ^ {t} = \\frac {1}{C} \\sum_ {c = 1} ^ {C} \\mathbb {E} _ {\\mathbf {z} \\sim \\mathcal {Z} _ {c} ^ {t}} \\left[ - \\log \\frac {1}{1 + \\exp^ {s (\\mathbf {z} ; \\mathbf {c} _ {W})}} \\right] \\tag {6} \\\\ + \\mathbb {E} _ {\\mathbf {x} \\sim S _ {\\mathrm {s p t}} ^ {t}} \\left[ - \\log \\frac {\\exp^ {s (\\mathbf {x} ; \\mathbf {f} _ {W , \\Phi , \\Theta})}}{1 + \\exp^ {s (\\mathbf {x} ; \\mathbf {f} _ {W , \\Phi , \\Theta})}} \\right], \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.439, + 0.469, + 0.484 + ], + "angle": 0, + "content": "where the score function \\( s \\) is introduced in Eq. (2). Therefore, we obtain the optimization problem for inner tasks by combining Eq. (3) and (6), i.e., for a parameter \\( \\lambda > 0 \\)," + }, + { + "type": "equation", + "bbox": [ + 0.149, + 0.491, + 0.469, + 0.515 + ], + "angle": 0, + "content": "\\[\n\\min _ {W, \\Phi} \\mathcal {L} ^ {t} = \\min _ {W, \\Phi} \\left[ \\mathcal {L} _ {\\mathrm {c e}} + \\mathcal {L} _ {\\mathrm {d}} ^ {t} + \\lambda \\mathcal {L} _ {\\mathrm {o o d}} ^ {t} \\right]. \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.523, + 0.469, + 0.631 + ], + "angle": 0, + "content": "Note that at the earlier training stage, we optimize \\(\\Phi\\), \\(W\\) only by using Eq. (3) so that a good estimation of ID distribution can be learned. Specifically, following VOS [8], we maintained a ID class-conditional queue \\(|Q_y|\\) for each class \\(y \\in \\mathcal{V}\\) for continuous online estimation of \\(\\hat{\\mu}_c^t\\) and \\(\\hat{\\Sigma}^t\\). The uncertainty regularization (Eq. (7)) is introduced in the middle of the training (i.e., at a certain starting epoch \\(E\\))." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.639, + 0.364, + 0.656 + ], + "angle": 0, + "content": "4.2. Learning A Meta-representation" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.662, + 0.469, + 0.8 + ], + "angle": 0, + "content": "Outer-loop Training. In Section 4.1, the inner training task only involves updating the adapter \\(\\mathbf{h}_{\\Phi}\\) and classifier \\(\\mathbf{c}_W\\) while keeping the feature extractor \\(\\mathbf{f}_{\\Theta}\\) fixed. In the outer loop, we target on updating \\(\\mathbf{f}_{\\Theta}\\) corresponding to fixed \\(\\Phi\\), \\(W\\) given in the inner tasks at each time \\(t \\in T_k'\\). Firstly, considering harnessing the knowledge transfer between continuous shifting distributions during time period \\(T_k'\\), we minimize the distribution discrepancy across the time period \\(T_k'\\): let \\(T_k' = \\{t_1', t_2', \\dots, t_l'\\}\\) with \\(t_1' < t_2' < \\dots < t_l'\\), then" + }, + { + "type": "equation", + "bbox": [ + 0.092, + 0.807, + 0.469, + 0.838 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {q r y}} = \\max _ {i \\in [ l - 1 ]} d _ {m k} ^ {2} \\left(\\mathbf {f} _ {\\Theta , \\Phi , W} \\left(S _ {\\mathrm {q r y}} ^ {t _ {i + 1} ^ {\\prime}}\\right), \\mathbf {f} _ {\\Theta , \\Phi , W} \\left(S _ {\\mathrm {q r y}} ^ {t _ {i} ^ {\\prime}}\\right)\\right), \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.846, + 0.469, + 0.902 + ], + "angle": 0, + "content": "where \\(\\mathbf{f}_{\\Theta ,\\Phi ,W}(S_{\\mathrm{qry}}^{t_i'}) = \\{\\mathbf{f}_{\\Theta ,\\Phi ,W}(\\mathbf{x}_{j,\\mathrm{qry}}^{t_i'})\\}_{j = 1}^{m't_i'}\\) here we set \\(S_{\\mathrm{qry}}^{t_i'} = \\{\\mathbf{x}_{j,\\mathrm{qry}}^{t_i'}\\}_{j = 1}^{m't_i}\\). Intuitively, \\(\\mathcal{L}_{\\mathrm{qry}}\\) estimates the discrepancies of continuously shifting distributions across the" + }, + { + "type": "code_caption", + "bbox": [ + 0.502, + 0.091, + 0.77, + 0.107 + ], + "angle": 0, + "content": "Algorithm 1. MOL in Training Process" + }, + { + "type": "algorithm", + "bbox": [ + 0.501, + 0.111, + 0.892, + 0.349 + ], + "angle": 0, + "content": "Input: ID training samples \\(S\\) and \\(\\{S^t\\}_{t\\in T_k}\\) ; learning rates \\(\\alpha ,\\beta\\) randomly initialized model \\(\\mathbf{f}_{W,\\Phi ,\\Theta} = \\mathbf{c}_W\\circ \\mathbf{h}_{\\Phi}\\circ \\mathbf{f}_{\\Theta}\\) while not done do Randomly initialized adapter \\(\\mathbf{h}_{\\Phi}\\) and classifier \\(\\mathbf{c}_W\\) Randomly sample \\(T_{k}^{\\prime} = \\{t_{1}^{\\prime},t_{2}^{\\prime},\\dots,t_{l}^{\\prime}\\}\\) from \\(T_{k}\\) and sample support and query sets \\(\\mathbf{S}_{\\mathrm{spt}}\\) and \\(\\mathbf{S}_{\\mathrm{qry}}\\) from \\(\\{S^t\\}_{t\\in T_k'}\\) for \\(i = 1\\) to \\(l\\) do Estimate \\(\\hat{\\mu}_c^{t_i}\\) and \\(\\hat{\\Sigma}^{t_i}\\) by using \\(S\\) and Eq. (4); Sample virtual OOD samples \\(Z_{c}^{t_{i}}\\) by Eq. (5); Compute \\(\\mathcal{L}^{t_i}\\) using \\(S,S_{\\mathrm{spt}}^{t_i}\\) and \\(Z_{c}^{t_{i}}\\) by Eq. (7); Update parameters: \\((\\Phi ,W)_{t_i + 1} = (\\Phi ,W)_{t_i} - \\alpha \\nabla \\mathcal{L}^{t_i}\\) end for Compute \\(\\mathcal{L}_{\\mathrm{meta}}\\) using \\(S\\) and \\(\\mathbf{S}_{\\mathrm{qry}}\\) by Eq. (9); Update parameters: \\(\\Theta = \\Theta -\\beta \\nabla \\mathcal{L}_{\\mathrm{meta}}\\) end while Output: initial model \\(G_{\\gamma}\\) \\((\\mathbf{x};s,\\mathbf{f}_{\\Theta ,\\Phi ,W})\\) by Eq. (1) meta-representation \\(\\mathbf{f}_{\\Theta}\\)" + }, + { + "type": "code_caption", + "bbox": [ + 0.502, + 0.368, + 0.762, + 0.383 + ], + "angle": 0, + "content": "Algorithm 2. MOL in Testing Process" + }, + { + "type": "algorithm", + "bbox": [ + 0.501, + 0.388, + 0.892, + 0.557 + ], + "angle": 0, + "content": "Input: ID training samples \\(S\\) and \\(\\{S^t\\}_{t\\in T_K^-}\\); learning rates \\(\\alpha, \\beta\\); meta-representation \\(\\mathbf{f}_{\\Theta}\\); score function introduced in Eq. (2). while not done do \nRandomly initialized adapter \\(\\mathbf{h}_{\\Phi}\\) and classifier \\(\\mathbf{c}_W\\); \nfor \\(i = K\\) to \\(N\\) do \nEstimate \\(\\hat{\\mu}_c^{t_i}\\) and \\(\\hat{\\Sigma}^{t_i}\\) by using \\(S\\) and Eq. (4); \nSample virtual OOD samples \\(Z_c^{t_i}\\) by Eq. (5); \nCompute \\(\\mathcal{L}^{t_i}\\) using \\(S\\), \\(S^{t_i}\\) and \\(Z_c^{t_i}\\) by Eq. (7); \nUpdate parameters: \\((\\Phi, W)_{t_{i+1}} = (\\Phi, W)_{t_i} - \\alpha \\nabla \\mathcal{L}^{t_i}\\); \nend for \nOutput: model \\(G_{\\gamma}(\\mathbf{x}; s, \\mathbf{f}_{\\Theta, \\Phi, W})\\) by Eq. (1). end while" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.567, + 0.892, + 0.598 + ], + "angle": 0, + "content": "time period \\( T_{k}^{\\prime} \\). Then, the optimization issue in outer-loop training can be represented as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.527, + 0.608, + 0.891, + 0.672 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\min _ {\\Theta} \\mathcal {L} _ {\\text {m e t a}} = \\min _ {\\Theta} \\left[ \\mathcal {L} _ {\\text {c e}} + \\mathcal {L} _ {\\text {q r y}} \\right. \\\\ \\left. + \\frac {1}{\\left| T _ {k} ^ {\\prime} \\right|} \\sum_ {t \\in T _ {k} ^ {\\prime}} \\left(\\mathcal {L} _ {\\mathrm {d}} ^ {t} + \\lambda \\mathcal {L} _ {\\mathrm {o o d}} ^ {t}\\right) \\right], \\tag {9} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.685, + 0.89, + 0.717 + ], + "angle": 0, + "content": "where \\(\\mathcal{L}_{\\mathrm{d}}^{t}\\) and \\(\\mathcal{L}_{\\mathrm{ood}}^{t}\\) are computed by using the samples \\(S_{\\mathrm{qry}}^{t}\\) in the query set \\(\\mathbf{S}_{\\mathrm{qry}}\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.717, + 0.892, + 0.824 + ], + "angle": 0, + "content": "In Eq. (9), the inner tasks (corresponding to \\(\\mathcal{L}_{\\mathrm{d}}^{t} + \\lambda \\mathcal{L}_{\\mathrm{odd}}^{t}\\)) across all time period \\(T_{k}^{\\prime}\\) are fed as one input (corresponding to \\(\\sum_{t\\in T_k'}\\left(\\mathcal{L}_{\\mathrm{d}}^t +\\lambda \\mathcal{L}_{\\mathrm{odd}}^t\\right) / |T_k^{\\prime}|\\)) in the outer-loop training. Thus, we are able to learn a good initialization of meta-representation \\(\\Theta\\) such that: when encountering a new distribution during testing, a few updating steps of \\(\\Phi ,W\\) result in a good performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.839, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Meta-testing. In the testing process, when exposed to previously unseen shifting distributions \\(D_{X_1Y_1}^t\\) (where \\(t \\in T_K^{-}\\)), we only need to fine-tune the adapter \\(\\mathbf{h}_{\\Phi}\\) and classifier \\(\\mathbf{c}_W\\) on the new test samples \\(S^t\\) (where \\(t \\in T_K^{-}\\)), while" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19357" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.199 + ], + "angle": 0, + "content": "keeping the meta-representation \\(\\mathbf{f}_{\\Theta}\\) fixed. This strategy enables fast adaptation by updating the lightweight classifier and adapter, which is useful for real-world online applications like self-driving agents. Furthermore, by incorporating the score function in Eq. (2), we can obtain an OOD detection model \\(g_{t}\\), while updating \\(\\mathbf{h}_{\\Phi}\\) and \\(\\mathbf{c}_W\\) at each time \\(t \\in T_K^-\\) during the testing process." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.213, + 0.21, + 0.23 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.238, + 0.429, + 0.254 + ], + "angle": 0, + "content": "5.1. Adaptive OOD Benchmark Construction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.263, + 0.47, + 0.429 + ], + "angle": 0, + "content": "For CAOOD evaluation, we construct 3 benchmarks (e.g., using Rotation MNIST, Cifar Corruption datasets as ID datasets) derived from commonly used static OOD benchmarks (e.g., MNIST, Cifar). Rotation MNIST and Corruption datasets are frequently used in continuous domain adaptation [53, 56]. In practical applications, rotation can replicate shifts arising from camera positions, while corruptions mimic various weather conditions (e.g., fog, snow) and movements (e.g., motion). In CAOOD, we evaluate both ID accuracy and OOD detection effectiveness. Dataset details are provided in the Appendix." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.429, + 0.47, + 0.549 + ], + "angle": 0, + "content": "Rotation MNIST [5]. This dataset has MNIST digits with various rotations from \\([0,180^{\\circ}]\\), and for each rotation, there are 60,000 training images. In our benchmark, we use Rotation MNIST (R-MNIST) as the ID training dataset and evaluate the OOD detection performance on Rotation NOTMNIST (R-NOTMNIST) and Rotation Cifar10bw (R-Cifar10bw). There are no semantics overlaps between the ID and OOD datasets." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.551, + 0.469, + 0.688 + ], + "angle": 0, + "content": "In our proposed MOL protocol, we consider images with rotation \\(0^{\\circ}\\) as the labeled original training samples \\(S\\), and images from rotation \\((0,180^{\\circ}]\\) as continuously shifting distributions over the whole time period \\((0,T]\\), i.e., \\(\\{S^t\\}_{t\\in T}\\). In meta-training, we use images from rotation \\((0 - 60^{\\circ}]\\) as \\(\\{S^t\\}_{t\\in T_k}\\), and randomly sample \\(\\mathbf{S}_{\\mathrm{spt}}\\), \\(\\mathbf{S}_{\\mathrm{qry}}\\) of length 10. During meta-testing, we update our model online for rotation \\(\\{S_{120^{\\circ}},S_{126^{\\circ}},i\\dots S_{174^{\\circ}}\\}\\), i.e., \\(\\{S^t\\}_{T_K^-}\\) and for each rotation, we only use 100 training samples for adaptation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.689, + 0.469, + 0.809 + ], + "angle": 0, + "content": "Cifar10C. This dataset consists of 15 types of corruptions (e.g., fog, brightness, motion, noise) with each demonstrating 5 levels of severity. We use Cifar10C as the ID data and test on two near OOD datasets applying the same shifting distribution: TinyimageNetC, and Cifar100C. Following the OOD benchmark literature [63], we create TinyimageNetC from a subset of the Tinyimagenet [49] where 1207 images overlap semantic labels with Cifar10 are removed." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.469, + 0.901 + ], + "angle": 0, + "content": "In our protocol, we take clean images from Cifar10 as original training samples \\(S\\), and consider images with various corruptions from Cifar10C as samples come from shifting distributions. Specifically, we design the continuous shifting distributions by gradually changing the severity across all corruption types, for example:" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.09, + 0.892, + 0.12 + ], + "angle": 0, + "content": "Table 1: OOD benchmarks used in our evaluation, including CAOD datasets, near OOD, and far OOD datasets." + }, + { + "type": "table", + "bbox": [ + 0.502, + 0.131, + 0.892, + 0.274 + ], + "angle": 0, + "content": "
ID DatasetCAOODNear OODFar OOD
R-MNISTR-NOTMNISTNOTMNISTCifar10bw
R-Cifar10bw
Cifar10CCifar100CCifar100Textures
TinyimagenetCTinyimageNetLSUN iSUN
Cifar100CCifar10CCifar10Textures
TinyimagenetCTinyimageNetLSUN iSUN
" + }, + { + "type": "equation", + "bbox": [ + 0.503, + 0.281, + 0.884, + 0.315 + ], + "angle": 0, + "content": "\\[\n\\underbrace {\\cdots , \\mathrm {C} _ {t - 1} ^ {5}} _ {\\text {t - 1 a n d b e f o r e}} \\rightarrow \\underbrace {\\mathrm {C} _ {t} ^ {1} , \\mathrm {C} _ {t} ^ {2} , \\mathrm {C} _ {t} ^ {3} , \\mathrm {C} _ {t} ^ {4} , \\mathrm {C} _ {t} ^ {5} , \\mathrm {C} _ {t} ^ {4} , \\mathrm {C} _ {t} ^ {3} , \\mathrm {C} _ {t} ^ {2} , \\mathrm {C} _ {t} ^ {1}} _ {\\text {c o r r u p t i o n t y p e t , c h a n g i n g g r a d u a l l y}} \\rightarrow \\underbrace {\\mathrm {C} _ {t + 1} ^ {1} , \\mathrm {C} _ {t + 1} ^ {2} , \\cdots} _ {\\text {t + 1 a n d o n}}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.316, + 0.892, + 0.452 + ], + "angle": 0, + "content": "In meta-training, we randomly sample \\(\\mathbf{S}_{\\mathrm{spt}}\\), \\(\\mathbf{S}_{\\mathrm{qry}}\\) of length 10 (i.e., \\(|T_k'| = 10\\)), from the first 7 corruptions of 63 continuously shifting distributions, i.e., \\(\\{S^t\\}_{t \\in T_k}\\), \\(|T_k| = 63\\). In meta-testing, we adapt our model to a trajectory of length 10 that is randomly sampled from the last 7 corruptions and evaluate on unseen test images from the last 7 corruptions (i.e., frost, fog, brightness, contrast, elastic transform, pixelate, jpeg compression). Similarly, we only had access to 100 training samples in meta-testing." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.453, + 0.892, + 0.572 + ], + "angle": 0, + "content": "Cifar100C [16]. This dataset is a variant of Cifar10C by applying the same corruptions to Cifar100. We used Cifar100C as the ID dataset and two near OOD datasets with the same continuous shifting distributions: Cifar10C and TinyImageNetC. We re-create TinyImageNetC after 2505 images sharing the same classes with Cifar100 have been removed [63]. For the MOL protocol, we applied the same training and testing fashion as used in Cifar10C." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.574, + 0.892, + 0.664 + ], + "angle": 0, + "content": "Standard OOD Datasets. In addition, we evaluate our method's OOD detection performance on commonly used OOD datasets from a static distribution, including Cifar10 and Cifar100 [26], TinyImageNet [49], Textures [27], LSUN-Resize, LSUN-Crop [66], and iSUN [61]. Table 1 summarizes evaluated OOD detection benchmarks." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.677, + 0.704, + 0.692 + ], + "angle": 0, + "content": "5.2. Baselines and Metrics" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.702, + 0.892, + 0.807 + ], + "angle": 0, + "content": "We compare our method with comprehensive OOD detection baselines including Maximum Softmax Probability [17], ODIN [32], Mahalanobis distance [29], energy score [34], Gram Metrics [45], Gradnorm [19], and the recent VOS [8], KNN [47] and LogitNorm [60]. To apply the above static OOD detection baselines in CAOOD, we use three different training/adapting schemes as follows." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.808, + 0.892, + 0.856 + ], + "angle": 0, + "content": "Direct Test. The model is trained on the labeled original training samples \\(S\\) and then directly test on continuously shifting \\(\\{S^t\\}_{t\\in T_K^-}\\) for OOD detection with no adaptation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Simple Adaptive. During training, the model is trained on the labeled original training samples \\( S \\). During testing, we finetune the classifier of the model to adapt to continuously" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19358" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.089, + 0.895, + 0.152 + ], + "angle": 0, + "content": "Table 2: Main Results on Rotation MNIST. \\(\\uparrow\\) (or \\(\\downarrow\\)) indicates greater (or smaller) values are preferred. For each comparable method, we report results on Direct Test / Simple Adaptive / Domain Adaptation. Only Direct Test results are reported for Gram and KNN, only Direct Test and Simple Adaptive results are reported for VOS and LogitNorm. The bold and * represent the best and second best performance and the shadow part marks our method." + }, + { + "type": "table", + "bbox": [ + 0.076, + 0.162, + 0.897, + 0.317 + ], + "angle": 0, + "content": "
MethodRotation NOTMNISTRotation Cifar10bwAverageID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
MSP76.9 / 75.9 / 62.371.9 / 70.4 / 87.690.1 / 89.4 / 68.855.6 / 48.5 / 83.683.5 / 82.6 / 65.664.8 / 59.5 / 85.625.6 / 28.3 / 27.2
ODIN63.6 / 76.7 / 30.885.2 / 72.6 / 56.787.3 / 88.1 / 67.658.2 / 50.9 / 83.975.5 / 82.4 / 49.271.7 / 61.8 / 70.325.6 / 28.3 / 27.2
Mahalanobis61.2 / 75.4 / 32.986.1 / 75.1 / 56.989.3 / 90.1 / 66.758.1 / 49.5 / 80.875.3 / 82.8 / 49.872.1 / 62.3 / 68.925.6 / 28.4 / 27.7
Energy92.6 / 91.7 / 72.736.1 / 39.7 / 76.197.5 / 95.9 / 69.112.6 / 19.9 / 85.295.1 / 93.8 / 70.924.4 / 29.8 / 80.725.6 / 28.3 / 27.2
Gram96.1*10.698.9*4.6*97.5*7.625.6
VOS86.7 / 93.557.6 / 32.392.7 / 96.731.0 / 16.489.7 / 95.144.3 / 24.427.7 / 30.9
LogitNorm84.0 / 94.046.2 / 29.797.7 / 99.010.5 / 4.590.0 / 96.528.3 / 17.124.7 / 31.5*
KNN95.716.591.425.093.520.824.9
MOL96.513.9*98.9*9.297.711.5*35.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.328, + 0.895, + 0.391 + ], + "angle": 0, + "content": "Table 3: Main Results on Cifar10 corruption. \\(\\uparrow\\) (or \\(\\downarrow\\)) indicates greater (or smaller) values are preferred. For each comparable method, we report results on Direct Test / Simple Adaptive / Domain Adaptation. Only Direct Test results are reported for Gram, Gradnorm, and KNN, only Direct Test and Simple Adaptive results are reported for VOS and LogitNorm. The bold and * represent the best performance and the shadow part marks our method." + }, + { + "type": "table", + "bbox": [ + 0.076, + 0.4, + 0.897, + 0.568 + ], + "angle": 0, + "content": "
MethodCifar100CTinyImagenetCAverageID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
MSP53.2 / 62.2 / 54.894.3 / 91.6 / 92.959.7 / 64.0 / 52.992.5 / 91.2 / 94.956.5 / 63.1 / 53.893.4 / 91.4 / 93.938.5 / 56.2 / 35.6
ODIN46.1 / 61.3 / 55.296.5 / 91.9 / 93.440.3 / 62.9 / 52.099.1 / 91.5 / 94.943.2 / 62.1 / 53.697.8 / 91.7 / 94.238.1 / 55.6 / 35.2
Mahalanobis46.8 / 63.6 / 55.196.7 / 91.3 / 93.447.0 / 66.0 / 53.698.1 / 90.6 / 93.946.9 / 64.8 / 54.497.4 / 90.9 / 93.738.5 / 56.2 / 35.6
Energy52.7 / 60.8 / 56.594.4 / 91.4 / 93.761.5 / 65.0 / 60.891.6 / 89.0 / 94.657.1 / 62.9 / 58.793.0 / 90.2 / 94.238.5 / 52.9 / 35.6
Gram55.289.766.582.560.986.1*38.1
Gradnorm29.597.241.396.535.496.938.5
VOS52.6 / 53.695.7 / 96.557.3 / 59.997.2 / 97.154.9 / 56.896.5 / 96.825.9 / 31.7
LogitNorm56.4 / 65.3*94.5 / 88.9*61.9 / 67.6*92.6 / 85.959.1 / 66.4*93.6 / 87.443.5 / 59.1*
KNN54.194.457.793.555.994.044.2
MOL69.786.371.485.6*70.685.964.1
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.592, + 0.47, + 0.655 + ], + "angle": 0, + "content": "shifting \\(\\{S^t\\}_{t\\in T_K^-}\\) dynamically and test their performance. Specifically, the classifier is updated using our proposed meta-testing strategy without virtual OOD generation and uncertainty regularization (i.e., by using Eq. 3)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.656, + 0.47, + 0.794 + ], + "angle": 0, + "content": "Domain Adaptation. The model is trained using classic domain adaptation techniques DAN [36]. Specifically, in the training process, we train the model offline by viewing \\( S \\) as the source domain and all shifting training samples \\( \\{S^t\\}_{t \\in T_k} \\) available as the target domain. During testing, we finetune the classifier of the model to adapt to continuously shifting \\( \\{S^t\\}_{t \\in T_K^-} \\) dynamically and test their performance (Eq. (3)). By doing so the Domain Adaptation strategy violates the CAOD setting during training." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Note that for Gram Metrics, Gradnorm, and KNN, only the Direct Test results are reported because their scoring functions are calculated based on feature representations across all layers, which demands a finetuning on the whole model during testing. For VOS and LogitNorm, only Direct Test and Simple Adaptive results are reported, as we found it difficult to train them with Domain Adaptation strategy." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.592, + 0.895, + 0.76 + ], + "angle": 0, + "content": "Evaluation Metrics. For OOD detection evaluation, we report 1) the area under the receiver operating characteristic curve (AUROC), which measures the model's capacity to distinguish ID and OOD samples based on varying thresholds of the predicted confidence scores; and 2) the false positive rate (FPR95) of OOD samples when the true positive rate of ID samples is fixed at \\(95\\%\\), which measures the percentage of OOD samples that are incorrectly classified as ID samples when the model's sensitivity to ID samples is high. For evaluating the ID classification, we report the commonly used accuracy." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.771, + 0.719, + 0.788 + ], + "angle": 0, + "content": "5.3. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.895, + 0.903 + ], + "angle": 0, + "content": "On the R-MNIST dataset, we use LeNet as the backbone for all models. As for Cifar10C and Cifar100C datasets, we use WideResNet as the backbone. Note that in our method, the last fully connected layers of LeNet and WideResNet are removed for learning meta-representation during training. We set the uncertainty regularization balancing term \\(\\lambda\\) as 0.015 for R-MNIST, and 0.1 for two CifarC datasets. The" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.958 + ], + "angle": 0, + "content": "19359" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.089, + 0.895, + 0.152 + ], + "angle": 0, + "content": "Table 4: Main Results on Cifar100 corruption. \\(\\uparrow\\) (or \\(\\downarrow\\)) indicates greater (or smaller) values are preferred. For each comparable method, we report results on Direct Test / Simple Adaptive / Domain Adaptation (DA). Only Direct Test results are reported for Gram, Gradnorm, and KNN, only Direct Test and Simple Adaptive results are reported for VOS and LogitNorm. The bold and * represent the best performance and the shadow part marks our method." + }, + { + "type": "table", + "bbox": [ + 0.076, + 0.162, + 0.897, + 0.31 + ], + "angle": 0, + "content": "
MethodTinyImagenetCCifar10CAverageID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
MSP50.9 / 61.3 / 58.194.8 / 91.3 / 92.558.2 / 64.0 / 61.292.9 / 91.2 / 91.354.6 / 62.7* / 59.793.4 / 91.3 / 91.927.8 / 41.4 / 37.7
ODIN49.1 / 59.7 / 55.595.5 / 91.4 / 93.641.8 / 63.5 / 60.298.0 / 90.8* / 91.645.5 / 61.6 / 57.996.8 / 91.1* / 92.227.8 / 41.4 / 37.7
Mahalanobis48.597.140.499.044.598.127.8
Energy50.7 / 58.0 / 61.6*94.9 / 92.1 / 91.0*58.7 / 63.6* / 61.092.9 / 91.4 / 92.654.7 / 60.8 / 61.393.9 / 91.8 / 91.827.8 / 41.4 / 37.7
Gram47.195.949.695.648.495.827.8
VOS49.9 / 52.196.0 / 96.352.6 / 54.897.7 / 98.051.3 / 53.596.9 / 97.226.1 / 43.1*
LogitNorm53.0 / 58.394.1 / 92.258.8 / 63.193.2 / 91.955.9 / 60.793.7 / 92.023.4 / 38.5
KNN51.795.150.094.950.995.022.9
MOL69.488.763.189.066.388.957.4
" + }, + { + "type": "image", + "bbox": [ + 0.16, + 0.329, + 0.345, + 0.452 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.396, + 0.329, + 0.58, + 0.452 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.631, + 0.329, + 0.813, + 0.451 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.46, + 0.895, + 0.493 + ], + "angle": 0, + "content": "Figure 3: The ID classification (a) and OOD detection performance (b-c) on R-MNIST benchmark over continuously shifting distributions. Our method achieved the best performance on all unseen distributions, i.e., the pink line." + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.513, + 0.47, + 0.543 + ], + "angle": 0, + "content": "Table 5: Average results over 10 randomly sampled trajectories on R-MNIST." + }, + { + "type": "table", + "bbox": [ + 0.078, + 0.555, + 0.47, + 0.622 + ], + "angle": 0, + "content": "
MethodR-NOTMNISTR-Cifar10bwID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
Fixed97.913.998.99.235.6
Sampled97.7 ±0.413.6 ±0.898.8 ±0.49.6 ±0.736.7 ±1.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.635, + 0.47, + 0.698 + ], + "angle": 0, + "content": "Table 6: Ablation study on R-MNIST, where w/o \\(\\mathcal{L}_{\\mathrm{ood}}\\) and w/o \\(\\mathcal{L}_{\\mathrm{qry}}\\) are variants trained without \\(\\mathcal{L}_{\\mathrm{ood}}\\) and \\(\\mathcal{L}_{\\mathrm{qry}}\\). E indicates the adding point of \\(\\mathcal{L}_{\\mathrm{ood}}\\), e.g., \\(1/2\\) indicates adding \\(\\mathcal{L}_{\\mathrm{ood}}\\) halfway through training." + }, + { + "type": "table", + "bbox": [ + 0.078, + 0.708, + 0.47, + 0.822 + ], + "angle": 0, + "content": "
MethodR-NOTMNISTR-Cifar10bwID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
w/o Lood94.134.997.612.234.2
w/o Lqry93.935.196.914.332.2
E = 1/399.77.499.95.628.7
E = 1/298.010.499.18.730.1
E = 2/396.513.998.99.235.6
E = 4/595.315.595.216.335.9
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.471, + 0.903 + ], + "angle": 0, + "content": "learning rates in inner/outer loops are set as 0.1/0.01 for R-MNIST, and 0.3/0.03 for two CIFarC datasets, respectively. We use SGD with 0.9 momentum and \\(5 \\times 10^{-4}\\) weight decay. On each OOD benchmark, all methods are trained us-" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.516, + 0.88, + 0.532 + ], + "angle": 0, + "content": "ing the same backbones with the same number of epochs." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.543, + 0.704, + 0.56 + ], + "angle": 0, + "content": "5.4. Experimental Results" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.567, + 0.892, + 0.749 + ], + "angle": 0, + "content": "Results on R-MNIST. Table 2 summarizes the ID classification and OOD detection results on R-MNIST. The baseline results show that most existing static OOD detection methods cannot handle ID classification and OOD detection when test samples compass continuous distribution shifts. By using an alternate scheme when we fine-tune the model's classifier during testing (i.e., Simple Adaptive), the comparable methods improved around \\(2.7\\%\\) in ID accuracy and reduced from \\(5.3\\%\\) to \\(19.3\\%\\) in FPR95 across all baselines. Such improvement endorses the dynamic adaptation of the OOD detection model when test samples come from continuously shifting distribution." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.895, + 0.903 + ], + "angle": 0, + "content": "When examining the performance of the Domain Adaptation strategy, results show that ID accuracy improved over the Direct Test baselines, however, the OOD detection performance dropped heavily, from \\(17.9\\%\\) to \\(26.3\\%\\) across all methods in AUROC. In contrast to the Domain Adaptation strategy, our method obtained superior performance (ID accuracy: \\(35.6\\%\\), AUROC: \\(97.7\\%\\)) by respecting the continuous shifting characteristic of test distributions. Note that although Gram [45] obtained the best results in FPR95, their ID accuracy (\\(10\\%\\) lower than our method) questioned the" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19360" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.468, + 0.106 + ], + "angle": 0, + "content": "reliability of the OOD detection performance in CAOOD." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.107, + 0.468, + 0.379 + ], + "angle": 0, + "content": "Results on Cifar Corruption. Table 3 and 4 show the OOD detection results on Cifar10C and Cifar100C. Results show that MOL achieved the best performance on both Cifar corruption benchmarks. On Cifar10C, we outperformed Direct Test, Simple Adaptive, and Domain Adaptation strategies by \\(25.6\\%\\), \\(7.9\\%\\), and \\(28.5\\%\\) in ID classification respectively. For OOD detection, we outperformed most comparable methods and adaptation strategies. Our AUROC outperformed the second-best result (i.e., Simple Adaptive LogitNorm) by \\(4.2\\%\\). On Cifar100C, we improved the 3 adaptation strategies by \\(29.6\\%\\), \\(16.0\\%\\), and \\(19.7\\%\\) respectively in ID accuracy, while maintaining the best average OOD detection performance when compared to all other methods. Note that in our reproduction, Gram shows a catastrophic OOD performance drop and Gradnorm obtained a \\(100\\%\\) in FPR95 when tested on the Cifar100C benchmark, which indicates the instability of their scoring functions using gradients/features across all layers when applied in CAOOD." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.381, + 0.468, + 0.516 + ], + "angle": 0, + "content": "Performance on Continuously Shifting Distribution. Figure 3 shows the ID classification and AUROC over distributions on the Rotation MNIST benchmark. It is clear to see that the OOD detection performance of VOS and Energy decreased when the distribution continues to shift, while our method maintained a good OOD detection (i.e., the purple line). This further endorses our method's superiority in addressing the CAOOD problem by learning to quickly adapt to newly arriving test samples with shifting distributions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.518, + 0.468, + 0.759 + ], + "angle": 0, + "content": "Discussion on the impact of Discretization. Theoretically, modeling in continuous time intervals requires infinite samples, making it unrealistic. As such discretization (using finite samples to simulate infinite samples) is a common way to address continuous domain adaptation [56, 2]. CIDA [53] employs closed intervals which uniformly sample finite time points from these intervals and obtain training data for each sampled time point. Following CIDA, instead of adapting to one fixed discretized trajectory, in meta-training, we adapt to randomly sampled trajectories (i.e., \\(\\mathbf{S}_{\\mathrm{spt}}, \\mathbf{S}_{\\mathrm{qry}}\\)) to approximate from \\(0^{\\circ}\\) to \\(60^{\\circ}\\). To further evaluate the impact of discretization on detection accuracy, we evaluate our method on 10 randomly sampled trajectories during testing. Table 5 shows the average results suggesting that the detection performance remains stable across various trajectories (fixed and sampled)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.771, + 0.229, + 0.787 + ], + "angle": 0, + "content": "5.5. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.468, + 0.901 + ], + "angle": 0, + "content": "A brief ablation analysis is provided in Table 6. Firstly, we build a variant of our model without \\(\\mathcal{L}_{\\mathrm{ood}}\\) by taking out the uncertainty regularization term \\(\\mathcal{L}_{\\mathrm{ood}}\\) so it reduces to focus solely on continuous ID adaptation without synthesizing virtual OOD samples for uncertainty regularization. By doing so the ID accuracy slightly dropped by \\(1.4\\%\\) while the OOD detection performance decreases noticeably (3.8% in" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.289 + ], + "angle": 0, + "content": "AUROC). Then, we conduct experiments on another variant without \\(\\mathcal{L}_{\\mathrm{qry}}\\) without the constraint term on distribution discrepancy \\(\\mathcal{L}_{\\mathrm{qry}}\\), leading to performance drops on all ID accuracy, AUROC, and FPR95. This reflects that harnessing knowledge transfer between distributions is indispensable to the CAOD problem. Further, we studied the impact on starting point of uncertainty regularization during the whole training process. Results show that an earlier start resulted in a significant drop in ID accuracy while the OOD detection performance is good but meaningless. We suggest that a balance should be identified whenever the ID accuracy is prioritized. More ablations, experimental results, and comparisons about training/testing time refer to the Appendix." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.299, + 0.777, + 0.315 + ], + "angle": 0, + "content": "6. Conclusion and Future Works" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.324, + 0.892, + 0.476 + ], + "angle": 0, + "content": "OOD detection has achieved great progress while facing challenges in real-world scenarios when test samples exhibit dynamic distribution shifting. Motivated by these challenges, we propose a novel and more realistic CAOD detection and develop an effective method of MOL in addressing this problem. To the best of our knowledge, we are the first to investigate OOD detection under continuous distribution shifts. Our proposal will motivate future works to pursue new methods in addressing real-world OOD detection under continuously shifting distributions." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.487, + 0.597, + 0.503 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.508, + 0.512, + 0.892, + 0.565 + ], + "angle": 0, + "content": "[1] Abhijit Bendale and Terrance Boult. Towards open world recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1893-1902, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.568, + 0.892, + 0.609 + ], + "angle": 0, + "content": "[2] Andreea Bobu, Eric Tzeng, Judy Hoffman, and Trevor Darryll. Adapting to continuously shifting domains. In International Conference on Learning Representations, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.61, + 0.892, + 0.692 + ], + "angle": 0, + "content": "[3] Jiefeng Chen, Yixuan Li, Xi Wu, Yingyu Liang, and Somesh Jha. Atom: Robustifying out-of-distribution detection using outlier mining. In Machine Learning and Knowledge Discovery in Databases. Research Track: European Conference, ECML PKDD 2021, Bilbao, Spain, September 13-17, 2021, Proceedings, Part III 21, pages 430-445. Springer, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.693, + 0.892, + 0.747 + ], + "angle": 0, + "content": "[4] Rui Dai, Yonggang Zhang, Zhen Fang, Bo Han, and Xinmei Tian. Moderately distributional exploration for domain generalization. International Conference on Machine Learning, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.749, + 0.892, + 0.789 + ], + "angle": 0, + "content": "[5] Li Deng. The mnist database of handwritten digit images for machine learning research. IEEE Signal Processing Magazine, 29(6):141-142, 2012." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.79, + 0.892, + 0.858 + ], + "angle": 0, + "content": "[6] Jiahua Dong, Yang Cong, Gan Sun, Zhen Fang, and Zhengming Ding. Where and how to transfer: Knowledge aggregation-induced transferability perception for unsupervised domain adaptation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 1(2):1-18, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.86, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[7] Jiahua Dong, Yang Cong, Gan Sun, Bineng Zhong, and Xiaowei Xu. What can be transferred: Unsupervised domain adaptation for endoscopic lesions segmentation. In" + }, + { + "type": "list", + "bbox": [ + 0.508, + 0.512, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "19361" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.111, + 0.093, + 0.468, + 0.12 + ], + "angle": 0, + "content": "IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4022-4031, June 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.122, + 0.468, + 0.176 + ], + "angle": 0, + "content": "[8] Xuefeng Du, Zhaoning Wang, Mu Cai, and Yixuan Li. Vos: Learning what you don't know by virtual outlier synthesis. In International Conference on Learning Representations, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.179, + 0.468, + 0.247 + ], + "angle": 0, + "content": "[9] Thomas Elsken, Benedikt Staffler, Jan Hendrik Metzen, and Frank Hutter. Meta-learning of neural architectures for few-shot learning. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12365-12375, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.25, + 0.468, + 0.303 + ], + "angle": 0, + "content": "[10] Zhen Fang, Yixuan Li, Jie Lu, Jiahua Dong, Bo Han, and Feng Liu. Is out-of-distribution detection learnable? Advances in Neural Information Processing Systems, 35:37199-37213, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.307, + 0.468, + 0.36 + ], + "angle": 0, + "content": "[11] Zhen Fang, Jie Lu, Anjin Liu, Feng Liu, and Guangquan Zhang. Learning bounds for open-set learning. In International Conference on Machine Learning, pages 3122-3132. PMLR, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.363, + 0.468, + 0.417 + ], + "angle": 0, + "content": "[12] Zhen Fang, Jie Lu, Feng Liu, and Guangquan Zhang. Semi-supervised heterogeneous domain adaptation: Theory and algorithms. IEEE Transactions on Pattern Analysis and Machine Intelligence, 45(1):1087-1105, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.42, + 0.468, + 0.473 + ], + "angle": 0, + "content": "[13] Chelsea Finn, Pieter Abbeel, and Sergey Levine. Model-agnostic meta-learning for fast adaptation of deep networks. In International Conference on Machine Learning, pages 1126–1135. PMLR, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.477, + 0.468, + 0.545 + ], + "angle": 0, + "content": "[14] Yaroslav Ganin, Evgeniya Ustinova, Hana Ajakan, Pascal Germain, Hugo Larochelle, François Laviolette, Mario Marchand, and Victor Lempitsky. Domain-adversarial training of neural networks. The journal of machine learning research, 17(1):2096-2030, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.548, + 0.468, + 0.601 + ], + "angle": 0, + "content": "[15] Arthur Gretton, Karsten M Borgwardt, Malte J Rasch, Bernhard Scholkopf, and Alexander Smola. A kernel two-sample test. The Journal of Machine Learning Research, 13(1):723-773, 2012." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.604, + 0.468, + 0.657 + ], + "angle": 0, + "content": "[16] Dan Hendrycks and Thomas Dietterich. Benchmarking neural network robustness to common corruptions and perturbations. In International Conference on Learning Representations, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.661, + 0.468, + 0.714 + ], + "angle": 0, + "content": "[17] Dan Hendrycks and Kevin Gimpel. A baseline for detecting misclassified and out-of-distribution examples in neural networks. In International Conference on Learning Representations, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.718, + 0.468, + 0.758 + ], + "angle": 0, + "content": "[18] Dan Hendrycks, Mantas Mazeika, and Thomas Dietterich. Deep anomaly detection with outlier exposure. In International Conference on Learning Representations, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.761, + 0.468, + 0.814 + ], + "angle": 0, + "content": "[19] Rui Huang, Andrew Geng, and Yixuan Li. On the importance of gradients for detecting distributional shifts in the wild. Advances in Neural Information Processing Systems, 34:677-689, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.818, + 0.468, + 0.871 + ], + "angle": 0, + "content": "[20] Rui Huang and Yixuan Li. Mos: Towards scaling out-of-distribution detection for large semantic space. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8710-8719, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.874, + 0.468, + 0.901 + ], + "angle": 0, + "content": "[21] Xiaowei Huang, Daniel Kroening, Wenjie Ruan, James Sharp, Youcheng Sun, Emese Thamo, Min Wu, and Xinping" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.093, + 0.468, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.147 + ], + "angle": 0, + "content": "Yi. A survey of safety and trustworthiness of deep neural networks: Verification, testing, adversarial attack and defence, and interpretability. Computer Science Review, 37:100270, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.15, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[22] Conor Igoe, Youngseog Chung, Ian Char, and Jeff Schneider. How useful are gradients for ood detection really? arXiv preprint arXiv:2205.10439, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.193, + 0.892, + 0.246 + ], + "angle": 0, + "content": "[23] Taewon Jeong and Heeyoung Kim. Ood-maml: Meta-learning for few-shot out-of-distribution detection and classification. Advances in Neural Information Processing Systems, 33:3907-3916, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.25, + 0.892, + 0.316 + ], + "angle": 0, + "content": "[24] KJ Joseph, Salman Khan, Fahad Shahbaz Khan, and Vineeth N Balasubramanian. Towards open world object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5830-5840, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.321, + 0.892, + 0.387 + ], + "angle": 0, + "content": "[25] KJ Joseph, Jathushan Rajasegaran, Salman Khan, Fahad Shahbaz Khan, and Vineeth N Balasubramanian. Incremental object detection via meta-learning. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(12):9209-9216, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.391, + 0.892, + 0.418 + ], + "angle": 0, + "content": "[26] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images. 2009." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.42, + 0.848, + 0.433 + ], + "angle": 0, + "content": "[27] Gustaf Kylberg. Kylberg texture dataset v. 1.0. 2011." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.436, + 0.892, + 0.49 + ], + "angle": 0, + "content": "[28] Balaji Lakshminarayanan, Alexander Pritzel, and Charles Blundell. Simple and scalable predictive uncertainty estimation using deep ensembles. Advances in neural information processing systems, 30, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.492, + 0.892, + 0.546 + ], + "angle": 0, + "content": "[29] Kimin Lee, Kibok Lee, Honglak Lee, and Jinwoo Shin. A simple unified framework for detecting out-of-distribution samples and adversarial attacks. Advances in neural information processing systems, 31, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.549, + 0.892, + 0.603 + ], + "angle": 0, + "content": "[30] KIMIN LEE, Kibok Lee, Honglak Lee, and Jinwoo Shin. Training confidence-calibrated classifiers for detecting out-of-distribution samples. In International Conference on Learning Representations, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.606, + 0.892, + 0.659 + ], + "angle": 0, + "content": "[31] Yi Li and Nuno Vasconcelos. Background data resampling for outlier-aware classification. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13218-13227, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.662, + 0.892, + 0.715 + ], + "angle": 0, + "content": "[32] Shiyu Liang, Yixuan Li, and R Srikant. Enhancing the reliability of out-of-distribution image detection in neural networks. In International Conference on Learning Representations, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.719, + 0.892, + 0.773 + ], + "angle": 0, + "content": "[33] Ziqian Lin, Sreya Dutta Roy, and Yixuan Li. Mood: Multi-level out-of-distribution detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 15313-15323, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.776, + 0.892, + 0.829 + ], + "angle": 0, + "content": "[34] Weitang Liu, Xiaoyun Wang, John Owens, and Yixuan Li. Energy-based out-of-distribution detection. Advances in neural information processing systems, 33:21464-21475, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.833, + 0.892, + 0.899 + ], + "angle": 0, + "content": "[35] Ziwei Liu, Zhongqi Miao, Xingang Pan, Xiaohang Zhan, Dahua Lin, Stella X Yu, and Boqing Gong. Open compound domain adaptation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12406-12415, 2020." + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.899 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.52, + 0.957 + ], + "angle": 0, + "content": "19362" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.148 + ], + "angle": 0, + "content": "[36] Mingsheng Long, Yue Cao, Jianmin Wang, and Michael Jordan. Learning transferable features with deep adaptation networks. In International Conference on Machine Learning, pages 97-105. PMLR, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.149, + 0.47, + 0.205 + ], + "angle": 0, + "content": "[37] Mingsheng Long, Han Zhu, Jianmin Wang, and Michael I Jordan. Deep transfer learning with joint adaptation networks. In International Conference on Machine Learning, pages 2208-2217. PMLR, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.207, + 0.469, + 0.248 + ], + "angle": 0, + "content": "[38] Andrey Malinin and Mark Gales. Predictive uncertainty estimation via prior networks. Advances in neural information processing systems, 31, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.249, + 0.469, + 0.303 + ], + "angle": 0, + "content": "[39] Yifei Ming, Ying Fan, and Yixuan Li. Poem: Out-of-distribution detection with posterior sampling. In International Conference on Machine Learning, pages 15650-15665. PMLR, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.305, + 0.469, + 0.359 + ], + "angle": 0, + "content": "[40] Yifei Ming, Yiyou Sun, Ousmane Dia, and Yixuan Li. Cider: Exploiting hyperspherical embeddings for out-of-distribution detection. arXiv preprint arXiv:2203.04450, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.362, + 0.469, + 0.417 + ], + "angle": 0, + "content": "[41] Yifei Ming, Hang Yin, and Yixuan Li. On the impact of spurious correlation for out-of-distribution detection. In Proceedings of the AAAI Conference on Artificial Intelligence, pages 10051-10059, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.419, + 0.469, + 0.473 + ], + "angle": 0, + "content": "[42] Sinno Jialin Pan, Ivor W Tsang, James T Kwok, and Qiang Yang. Domain adaptation via transfer component analysis. IEEE Transactions on Neural Networks, 22(2):199-210, 2010." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.476, + 0.469, + 0.545 + ], + "angle": 0, + "content": "[43] Juan-Manuel Perez-Rua, Xiatian Zhu, Timothy M Hospedales, and Tao Xiang. Incremental few-shot object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13846-13855, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.547, + 0.469, + 0.601 + ], + "angle": 0, + "content": "[44] Shafin Rahman, Salman H Khan, and Fatih Porikli. Zero-shot object detection: Joint recognition and localization of novel concepts. International Journal of Computer Vision, 128:2979-2999, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.603, + 0.469, + 0.657 + ], + "angle": 0, + "content": "[45] Chandramouli Shama Sastry and Sageev Oore. Detecting out-of-distribution examples with gram matrices. In International Conference on Machine Learning, pages 8491-8501. PMLR, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.66, + 0.469, + 0.702 + ], + "angle": 0, + "content": "[46] Yiyou Sun, Chuan Guo, and Yixuan Li. React: Out-of-distribution detection with rectified activations. Advances in Neural Information Processing Systems, 34:144-157, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.703, + 0.469, + 0.757 + ], + "angle": 0, + "content": "[47] Yiyou Sun, Yifei Ming, Xiaojin Zhu, and Yixuan Li. Out-of-distribution detection with deep nearest neighbors. In International Conference on Machine Learning, pages 20827-20840. PMLR, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.759, + 0.469, + 0.814 + ], + "angle": 0, + "content": "[48] Jihoon Tack, Sangwoo Mo, Jongheon Jeong, and Jinwoo Shin. Csi: Novelty detection via contrastive learning on distributionally shifted instances. Advances in neural information processing systems, 33:11839-11852, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.817, + 0.469, + 0.871 + ], + "angle": 0, + "content": "[49] Antonio Torralba, Rob Fergus, and William T Freeman. 80 million tiny images: A large data set for nonparametric object and scene recognition. IEEE Transactions on pattern analysis and machine intelligence, 30(11):1958-1970, 2008." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[50] Joost Van Amersfoort, Lewis Smith, Yee Whye Teh, and Yarin Gal. Uncertainty estimation using a single deep de" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "terministic neural network. In International Conference on Machine Learning, pages 9690-9700. PMLR, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.122, + 0.892, + 0.177 + ], + "angle": 0, + "content": "[51] Sachin Vernekar, Ashish Gaurav, Vahdat Abdelzad, Taylor Denouden, Rick Salay, and Krzysztof Czarnecki. Out-of-distribution detection in classifiers via generation. arXiv preprint arXiv:1910.04241, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.179, + 0.892, + 0.219 + ], + "angle": 0, + "content": "[52] Ricardo Vilalta and Youssef Drissi. A perspective view and survey of meta-learning. Artificial intelligence review, 18:77-95, 2002." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.221, + 0.892, + 0.263 + ], + "angle": 0, + "content": "[53] Hao Wang, Hao He, and Dina Katabi. Continuously indexed domain adaptation. In Proceedings of the 37th International Conference on Machine Learning, pages 9898-9907, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.265, + 0.892, + 0.32 + ], + "angle": 0, + "content": "[54] Haoqi Wang, Zhizhong Li, Litong Feng, and Wayne Zhang. Vim: Out-of-distribution with virtual-logit matching. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4921-4930, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.321, + 0.892, + 0.39 + ], + "angle": 0, + "content": "[55] Haotao Wang, Aston Zhang, Yi Zhu, Shuai Zheng, Mu Li, Alex J Smola, and Zhangyang Wang. Partial and asymmetric contrastive learning for out-of-distribution detection in long-tailed recognition. In International Conference on Machine Learning, pages 23446-23458. PMLR, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.392, + 0.892, + 0.448 + ], + "angle": 0, + "content": "[56] Qin Wang, Olga Fink, Luc Van Gool, and Dengxin Dai. Continual test-time domain adaptation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7201-7211, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.449, + 0.892, + 0.504 + ], + "angle": 0, + "content": "[57] Qizhou Wang, Feng Liu, Yonggang Zhang, Jing Zhang, Chen Gong, Tongliang Liu, and Bo Han. Watermarking for out-of-distribution detection. In Advances in Neural Information Processing Systems, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.506, + 0.892, + 0.574 + ], + "angle": 0, + "content": "[58] Qizhou Wang, Junjie Ye, Feng Liu, Quanyu Dai, Marcus Kalander, Tongliang Liu, Jianye Hao, and Bo Han. Out-of-distribution detection with implicit outlier transformation. In International Conference on Learning Representations. OpenReview.net, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.577, + 0.892, + 0.632 + ], + "angle": 0, + "content": "[59] Zitai Wang, Qianqian Xu, Zhiyong Yang, Yuan He, Xiaochun Cao, and Qingming Huang. Openauc: Towards auc-oriented open-set recognition. Advances in Neural Information Processing Systems, 35:25033-25045, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.634, + 0.892, + 0.689 + ], + "angle": 0, + "content": "[60] Hongxin Wei, Renchunzi Xie, Hao Cheng, Lei Feng, Bo An, and Yixuan Li. Mitigating neural network overconfidence with logit normalization. In International Conference on Machine Learning, pages 23631-23644. PMLR, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.69, + 0.892, + 0.759 + ], + "angle": 0, + "content": "[61] Jianxiong Xiao, James Hays, Krista A Ehinger, Aude Oliva, and Antonio Torralba. Sun database: Large-scale scene recognition from abbey to zoo. In 2010 IEEE computer society Conference on Computer Vision and Pattern Recognition, pages 3485-3492. IEEE, 2010." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.761, + 0.892, + 0.83 + ], + "angle": 0, + "content": "[62] Jingkang Yang, Haoqi Wang, Litong Feng, Xiaopeng Yan, Huabin Zheng, Wayne Zhang, and Ziwei Liu. Semantically coherent out-of-distribution detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 8301-8309, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.832, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[63] Jingkang Yang, Pengyun Wang, Dejian Zou, Zitang Zhou, Kunyuan Ding, Wenxuan Peng, Haoqi Wang, Guangyao Chen, Bo Li, Yiyou Sun, et al. Openood: Benchmarking generalized out-of-distribution detection. Advances in Neural Information Processing Systems, 35:32598-32611, 2022." + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "19363" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.134 + ], + "angle": 0, + "content": "[64] Jingkang Yang, Kaiyang Zhou, Yixuan Li, and Ziwei Liu. Generalized out-of-distribution detection: A survey. arXiv preprint arXiv:2110.11334, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.47, + 0.175 + ], + "angle": 0, + "content": "[65] Jingkang Yang, Kaiyang Zhou, and Ziwei Liu. Full-spectrum out-of-distribution detection. arXiv preprint arXiv:2204.05306, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.179, + 0.469, + 0.233 + ], + "angle": 0, + "content": "[66] Fisher Yu, Ari Seff, Yinda Zhang, Shuran Song, Thomas Funkhouser, and Jianxiong Xiao. Lsun: Construction of a large-scale image dataset using deep learning with humans in the loop. arXiv preprint arXiv:1506.03365, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.235, + 0.469, + 0.29 + ], + "angle": 0, + "content": "[67] Li Zhong, Zhen Fang, Feng Liu, Bo Yuan, Guangquan Zhang, and Jie Lu. Bridging the theoretical bound and deep algorithms for open set domain adaptation. IEEE Transactions on Neural Networks and Learning Systems, 2021." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.29 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.946, + 0.519, + 0.956 + ], + "angle": 0, + "content": "19364" + } + ] +] \ No newline at end of file diff --git a/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/06d792b4-9c42-4f8e-baa6-449a229309f7_origin.pdf b/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/06d792b4-9c42-4f8e-baa6-449a229309f7_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..8a161800d9b9b165a4c73fd3e2d41bcd7bad1879 --- /dev/null +++ b/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/06d792b4-9c42-4f8e-baa6-449a229309f7_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:bb4bc1128ca3d377f8a8031754dc3a6d17b5909d73d3aef6f8c2b27283dc485f +size 6480843 diff --git a/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/full.md b/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/full.md new file mode 100644 index 0000000000000000000000000000000000000000..7d59b4a7ded5944e684812749c66911dbec23cd2 --- /dev/null +++ b/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/full.md @@ -0,0 +1,388 @@ +# Meta OOD Learning For Continuously Adaptive OOD Detection + +Xinheng Wu† Jie Lu† Zhen Fang† Guangquan Zhang† + +†Australian Artificial Intelligence Institute, University of Technology Sydney + +Xinheng.Wu@student.uts.edu.au {Jie.Lu, Zhen.Fang, Guangquan.Zhang}@uts.edu.au* + +# Abstract + +Out-of-distribution (OOD) detection is crucial to modern deep learning applications by identifying and alerting about the OOD samples that should not be tested or used for making predictions. Current OOD detection methods have made significant progress when in-distribution (ID) and OOD samples are drawn from static distributions. However, this can be unrealistic when applied to real-world systems which often undergo continuous variations and shifts in ID and OOD distributions over time. Therefore, for an effective application in real-world systems, the development of OOD detection methods that can adapt to these dynamic and evolving distributions is essential. In this paper, we propose a novel and more realistic setting called continuously adaptive out-of-distribution (CAOD) detection which targets on developing an OOD detection model that enables dynamic and quick adaptation to a new arriving distribution, with insufficient ID samples during deployment time. To address CAOD, we develop meta OOD learning (MOL) by designing a learning-to-adapt diagram such that a good initialized OOD detection model is learned during the training process. In the testing process, MOL ensures OOD detection performance over shifting distributions by quickly adapting to new distributions with a few adaptations. Extensive experiments on several OOD benchmarks endorse the effectiveness of our method in preserving both ID classification accuracy and OOD detection performance on continuously shifting distributions. + +# 1. Introduction + +Out-of-distribution (OOD) detection is vital to modern deep learning (DL) applications in the real world, especially in safety-critical applications such as autonomous vehicle control [21], and medical areas [64]. This is because DL systems may make over-confident and incorrect predictions when encountering the out-of-distribution (OOD) samples, which possess semantic labels that are distinct from those + +![](images/9074d848afddb7d879dfd4391f528393b7a4670a1fa560a8d108a14404cc2d1c.jpg) +Figure 1: Difference between existing static OOD detection and a more realistic scenario of Continuously Adaptive OOD Detection (Problem 1) when test samples come from continuously shifting distribution, i.e., Definition 1. + +of in-distribution (ID) samples [63]. To mitigate this issue, an important problem out-of-distribution detection has been proposed and studied extensively [10, 17]. In OOD detection, the classifier is required to perform accurate predictions on ID samples while simultaneously identifying OOD samples. Many representative methods either utilize outputs [17, 34], feature representations [29, 45], or gradients [19, 32] to enlarge the separations between ID and OOD samples, while others [18, 39] incorporate auxiliary OOD samples to regularize the deep models during training. + +Although OOD detection has achieved great progress, existing methods only focus on a simple scenario where ID and OOD samples are assumed to be drawn from static ID and OOD distributions. However, many real-world systems are changing dynamically and thus inherently exhibit continuous distribution shifts over time. Take a self-driving agent equipped with a scene recognition system as an example: in the real world, the surrounding environment (e.g., illumination, weather) may shift continuously on the road, such as from day to night, and from clean to foggy. Treating the arriving training and test samples as from static distributions may potentially harm the effectiveness of OOD detection, leading to the misclassification of distribution-shifted + +ID and OOD samples. Such scenarios highlight the limitations of current OOD detection methods when applied to continuously shifting distributions. Figure 1 highlights the difference between OOD detection on static distribution and when applying to continuously shifting distributions. + +To tackle the continuously shifting scenarios in OOD detection, we propose a novel and realistic setting termed continuously adaptive out-of-distribution (CAOOD) detection, which targets on developing OOD detection method to 1) quickly adapt to the continuously shifting ID distributions and 2) detect the continuously shifting OOD samples over time. Note that during the deployment time, the ID samples may be insufficient during the adaptation process. Therefore, how to enable dynamic and quick adaptation with insufficient ID samples to achieve good OOD detection performance over time is core challenge of CAOOD detection. + +Inspired by domain adaptation [14, 6] and meta-learning [13], we develop a novel and effective CAOD detection method called meta out-of-distribution learning (MOL) to address the challenge in CAOD detection. To dynamically and quickly adapt to the continuously shifting ID samples, we leverage the learning-to-learn paradigm [52] of meta-learning which aims to learn an internal representation for quick adaptation to a new task. Specifically, by formulating adaptations to the continuous shifting ID samples as a variety of inner tasks, we design a meta-training procedure for learning to adapt explicitly. Further, to facilitate quick adaptation with insufficient ID samples, we propose to learn a meta-representation during training, which allows us to only update the light-weighted classifier during testing while keeping the meta-representation fixed. Additionally, considering OOD samples are unavailable in training, we propose to generate OOD samples based on the shifting ID feature representations. Lastly, the classifier is trained discriminatively based on both ID and virtual OOD samples. + +The contributions are summarized as follows: + +- We propose a more realistic OOD detection setting called CAOD detection to promote the applications of OOD detection techniques in real-world scenarios. +- We develop technologies based on meta-learning and domain adaptation to quickly adapt to the continuously shifting ID distributions. With these technologies, MOL is proposed to address CAOD detection. +- We conduct extensive experiments comparing MOL with competitive OOD detection methods using various fine-tuning/adaptation strategies on 114 CAOOD detection tasks. Experiments show that MOL achieves the best performance for both ID classification and OOD detection in continuously shifting distributions. + +# 2. Related Work + +Out-of-distribution Detection methods are mainly post-hoc based adopting different scoring functions based on either logit outputs [17, 32, 34, 46, 28, 20], feature representations [45, 29, 33, 54, 47], or gradients [32, 19, 22]. These methods enjoy good applicability when deployed as they can be easily integrated into a pre-trained model without retraining. Other works utilize contrastive learning [48, 47, 55], specifically designed loss functions [60, 38, 40]. However, these methods often require sophisticated score functions but may not necessarily outperform post-hoc methods in general as noted by [63]. Another line of OOD detection methods focus on regularizing the training of classifier using either auxiliary OOD datasets or generated fake OOD samples [18, 30, 34]. These works study sampling strategies [39, 3, 31], OOD samples generation approaches [30, 51, 8], and uncertainty regularization mechanisms [50]. In addition to above strategies, other strategies have also been explored. For example, to overcome the intrinsic inconsistency of prior metrics by aggregating both the known and unknown class performance in a single performance curve, [59] propose a novel OOD detection metric named OpenAUC as the final objective function to learn OOD detector. + +Above OOD detection methods neglect inevitable distribution shifts in test data over time in real-world applications. Very few OOD detection works consider such shift: one work [62] used a large unlabeled dataset containing ID samples aiming to encourage ID semantic information modeling while being robust to covariate shift. Another work [65] considers explicitly promotes the generalization capacity of the OOD detector when being evaluated on covariate-shifted ID data. Recent work [41] discovers that environmental-related features (e.g., backgrounds) significantly worsen existing OOD detection performance. These early attempts highlight existing OOD detection methods are prone to distribution shifts and consequently inadequate for realistic scenarios, which motivates our research. + +Domain Adaptation (DA) aims to adapt machine learning models to unseen and different distributions [12, 64, 67, 7]. In complementary to OOD detection, DA improves models' generalization ability to covariate shift when test data share the same label set as training [35, 4]. Most existing DA methods focus on matching discrete source and target domains leveraging domain statistics [42], distance-based loss functions [37], and adversarial training [14]. Recently, different methods are developed to perform continuous domain adaptation when the target domain shifts smoothly over time [2, 53, 56]. Continuous domain adaptation is related to our problem but it does not follow an open-world assumption where test data may contain OOD samples that do not belong to the training label set. In this paper, we address a more challenging open-world learning scenario, OOD detection under continuous shifting distributions. + +Open World Recognition aims to incrementally learn new information without forgetting in an open world [24, 1, 11]. This problem concentrates on zero-shot learning [44], mitigating catastrophic forgetting [25], and incremental learning [43], where unknown samples can be progressively labeled as inputs. This is different from our focus on learning an open-world classifier that can quickly adapt to continuously shifted domains online while maintaining both ID and OOD detection performance. Additional literature on the topic of meta-learning is included in the Appendix. + +# 3. Problem Setup and Notations + +OD Detection. Let $\mathcal{X}$ denote the feature space, $\mathcal{Y} = [C]$ be the label space. We consider the ID distribution $D_{X_1Y_1}$ as a joint distribution defined over $\mathcal{X}\times \mathcal{Y}$ , where $X_{\mathrm{I}}$ and $Y_{\mathrm{I}}$ are random variables whose outputs are from spaces $\mathcal{X}$ and $\mathcal{Y}$ . Given a set of $n$ samples drawn i.i.d. from the ID distribution called ID data, $S = \{(\mathbf{x}_j,y_j)\}_{j = 1}^n\sim D_{X_1Y_1}$ . A classic classification model $\mathbf{f}:\mathcal{X}\to \mathbb{R}^{C}$ , is trained on the training set $S$ , to predict the label of an input test data [10]. + +During the test time of OOD detection, the test samples contain some unknown OOD samples drawn from an OOD distribution $D_{X_0Y_0}$ , where $X_0$ is a random variable from $\mathcal{X}$ , but $Y_0$ is a random variable whose outputs do not belong to $\mathcal{Y}$ , i.e., $Y_0 \notin \mathcal{Y}$ . The classical OOD detection methods aim to design an effective score function $s(\cdot; \mathbf{f}): \mathcal{X} \to \mathbb{R}$ [32, 29, 34] and train a corresponding model $\mathbf{f}$ by ID samples $S$ such that the following OOD detector + +$$ +G _ {\gamma} (\mathbf {x}; s, \mathbf {f}) = \left\{ \begin{array}{l l} \text {I D} & \text {i f} s (\mathbf {x}; \mathbf {f}) \geq \gamma \\ \text {O O D} & \text {i f} s (\mathbf {x}; \mathbf {f}) < \gamma \end{array} \right. \tag {1} +$$ + +where $\gamma$ is a threshold can distinguish ID and OOD samples accurately. In this paper, we select $\gamma$ when $95\%$ ID data is correctly classified [63, 58, 57], and use energy score [34] as the scoring function to design our OOD detector, i.e., + +$$ +s (\mathbf {x}; \mathbf {f}) = \log \sum_ {l = 1} ^ {C} \exp (f _ {l} (\mathbf {x})) \tag {2} +$$ + +where $f_{l}(\mathbf{x})$ is the $l$ -th coordinate of $\mathbf{f}(\mathbf{x})$ . + +Continuously Adaptive OOD Detection. To tackle more realistic scenarios that the ID and OOD samples are from continuously shifting distributions over a discrete time period $T = \{t_1, t_2, \dots, t_N\}$ , which satisfies that $0 < t_1 < t_2 < \dots < t_N$ . We also set $T_k = \{t_1, t_2, \dots, t_k\}$ and set $T_K^- = \{t_K, t_{K+1}, \dots, t_N\}$ , where $1 \leq k < K \leq N$ . It is clear that $T_k \cup T_K^- \subset T$ and $T_k \cap T_K^- = \emptyset$ . Next, the definition of continuously shifting ID and OOD distributions is given in Definition 1. + +![](images/7fe2311f62c252f98969cdc3178bd8fe9b74118ac199578b4527867524a2c396.jpg) +Figure 2: A heuristic illustration CAOD problem. The target is to train an OOD detection model $g_{0}$ using S, $\{S^t\}_{t \in T_k}$ so it can obtain good OOD detection performance on unseen shifting samples $\{S^t\}_{t \in T_K^-}$ by quick adaptation. + +Definition 1 (Continuously Shifting Distributions.) Let $D_{X_1Y_1}^t$ and $D_{X_0Y_0}^t$ are $ID$ and OOD joint distributions at time $t \in T$ . We say $D_{X_1Y_1}^t, D_{X_0Y_0}^t$ are continuously shifting $ID$ and OOD distributions, if for any $i \in [N-1]$ , + +$$ +\begin{array}{l} d \left(D _ {X _ {1} Y _ {1}} ^ {t _ {i}}, D _ {X _ {1} Y _ {1}} ^ {t _ {i + 1}}\right) < \epsilon , \\ d (D _ {X _ {\mathrm {O}}} ^ {t _ {i}}, D _ {X _ {\mathrm {O}}} ^ {t _ {i + 1}}) < \epsilon , \\ \end{array} +$$ + +where $d(\cdot, \cdot)$ is a distribution metric and $\epsilon$ is a small value. + +In Definition 1, the small value $\epsilon$ is used to estimate the gradual variations and quantify the continuity of continuously shifting ID and OOD distributions. We note here that distribution shift over time can be significant as it gradually accumulates. Next, we give the definition of continuously adaptive OOD detection. + +# Problem 1 (Continuously Adaptive OOD Detection.) + +Let $D_{X_{\mathrm{I}}Y_{\mathrm{I}}}^{t}$ and $D_{X_{\mathrm{O}}Y_{\mathrm{O}}}^{t}$ be the continuously shifting ID and OOD distributions over time period $T$ and let $D_{X_{\mathrm{I}}Y_{\mathrm{I}}}$ be the original ID distribution. Given sets of samples + +$$ +S = \left\{\left(\mathbf {x} _ {1}, y _ {1}\right), \dots , \left(\mathbf {x} _ {n}, y _ {n}\right) \right\} \sim D _ {X _ {1} Y _ {1}}, i. i. d. +$$ + +$$ +S ^ {t} = \left\{\mathbf {x} _ {1} ^ {t}, \dots , \mathbf {x} _ {n} ^ {t} \right\} \sim D _ {X _ {1}} ^ {t}, i. i. d., f o r e a c h t \in T +$$ + +with $n^t \ll n$ if $t \in T_K^-$ , the aim of continuously adaptive OOD detection is to train an initial OOD detection model $g_0$ using $S$ , $\{S^t\}_{t \in T_k}$ , and to quickly update the model $g_{t_i}$ (at each time $t_i \in T_K^- = \{t_K, t_{K+1}, \dots, t_N\}$ ) based on the previous model $g_{t_{i-1}}$ ( $g_0$ is the initial model, i.e., $g_{t_{K-1}} = g_0$ ) using $S$ , $S^{t_i}$ . Such that for any test sample $\mathbf{x} \in \{S^t\}_{t \in T_K^-}$ : 1) if $\mathbf{x}$ is from ID distribution $D_{X_1}^t$ , $g_{t_N}$ classifies $\mathbf{x}$ into correct ID label; and 2) if $\mathbf{x}$ is from OOD distribution $D_{X_0}^t$ , $g_{t_N}$ detects $\mathbf{x}$ as OOD. + +A heuristic illustration of the CAOD problem is provided in Figure 2. The key challenge of Problem 1 is to quickly adapt to new ID distribution $D_{X_1}^{t_i}$ using insufficient ID samples $S^{t_i}$ at time $t_i$ . To achieve satisfied performance + +across time period $T_{K}^{-}$ , a good initial OOD detection model $g_{0}$ is indispensable for effective adaptation. In Section 4, we illustrate the proposed MOL method and detail how to obtain the initial model $g_{0}$ during the training procedure. + +Notations. To facilitate better comprehension, we introduce some necessary notations. To learn a good initial OOD detection model $g_{0}$ , we mainly use meta-learning techniques. Following the meta-training procedure [13], we need to sample a support set $\mathbf{S}_{\mathrm{spt}} = \{S_{\mathrm{spt}}^{t}\}_{t\in T_{k}^{\prime}}$ from $\{S^t\}_{t\in T_k}$ where $T_{k}^{\prime}\subset T_{k}$ and $S_{\mathrm{spt}}^{t}\subset S^{t}$ . We also need to sample a query set $\mathbf{S}_{\mathrm{qry}} = \{S_{\mathrm{qry}}^{t}\}_{t\in T_{k}^{\prime}}$ from $\{S^t\}_{t\in T_k}$ , where $S_{\mathrm{qry}}^{t}\subset S^{t}$ . Further, we set $\mathbf{f}_{\Theta}$ to be the feature extractor, set $\mathbf{h}_{\Phi}$ to be the adapter, and set $\mathbf{c}_W$ to be the classifier, where $\Theta ,\Phi$ and $W$ are the parameters. Then the classification model $\mathbf{f}$ can be expressed as a function composition: + +$$ +\mathbf {f} _ {W, \Phi , \Theta} = \mathbf {c} _ {W} \circ \mathbf {h} _ {\Phi} \circ \mathbf {f} _ {\Theta}. +$$ + +Lastly, the OOD detection model $G_{\gamma}$ can be obtained via the score function $s(\cdot ;\mathbf{f}_{W,\Phi ,\Theta})$ as shown in Eqs. 1 and 2. + +To adapt the shifting distributions, we mainly utilize the maximum mean discrepancy (MMD) [15], which are introduced in following: given samples $\{\mathbf{x}_i\}_{i=1}^n$ and $\{\mathbf{x}_j'\}_{j=1}^m$ , + +$$ +\begin{array}{l} d _ {k} (\{\mathbf {x} _ {i} \} _ {i = 1} ^ {n}, \{\mathbf {x} _ {j} ^ {\prime} \} _ {j = 1} ^ {m}) \\ = \left\| \frac {1}{n} \sum_ {i = 1} ^ {n} \phi_ {k} (\mathbf {x} _ {i}) - \frac {1}{m} \sum_ {i = 1} ^ {m} \phi_ {k} (\mathbf {x} _ {j}) \right\| _ {k}, \\ \end{array} +$$ + +where $k$ is the kernel and $\phi_{k}$ is the kernel feature map. To further improve the adaptive performance, in this work, we use the multi-kernel MMD $d_{mk}$ , which is shown in [36]. + +# 4. Methodology + +It is important to recognize that while the number of test samples $S^t (t \in T_K^-)$ may be limited during deployment, we often have access to a satisfactory number of labeled training samples $S$ as well as unlabeled samples $\{S^t\}_{t \in T_k}$ that can be used to simulate distribution shifts that may occur during deployment. This motivates us to learn a well-designed initial OOD detection model $g_0$ that utilizes both labeled training samples $S$ and unlabeled samples $\{S^t\}_{t \in T_k}$ to effectively adapt to the shifting test samples $S^t (t \in T_K^-)$ as defined in Problem 1. + +To develop an effective initial OOD detection model $g_0$ , we consider learning an internal meta-representation that enables efficient adaptation to the new distributions in Problem 1. Additionally, note that OOD samples are unavailable during the training process, we utilize the virtual OOD synthesize [8] techniques to generate reliable-virtual OOD samples. The virtual OOD samples emulate real OOD samples and thus enable the classifier to be trained with an additional uncertainty regularization term that incorporates both ID and virtual OOD information. + +An effective strategy of learning $g_{0}$ is to draw upon the experience of meta-learning [9, 52]. Originally proposed for addressing few-shot learning [9, 23], meta-learning involves utilizing fast adaptation on a small number of samples. By using meta-learning [13], we can efficiently adapt the initial model to new distributions encountered during deployment. Specifically, a meta-training process is explicitly designed for learning-to-adapt by viewing the adaptation to each time $t \in T_k'$ for OOD detection as the inner tasks, thus dynamic adaptations across all time periods $T_k'$ can be regarded as one input for the outer-loop training process. Concretely, we can train the classifier by considering both ID adaptation and OOD uncertainty regularization. In the outer loop, we update the model with respect to many inner tasks across all time periods $T_k'$ . We detail the inner learning tasks and outer-loop meta-training process in Sections 4.1 and 4.2. The entire procedures of the proposed MOL method are shown in Algorithms 1 and 2. + +# 4.1. Inner Learning Task for MOL + +ID Adaptation. In the inner task, we firstly train the adapter $\mathbf{h}_{\Phi}$ and classifier $\mathbf{c}_W$ to adapt to current ID distribution at time point $t \in T_k'$ using support set $\mathbf{S}_{\mathrm{spt}}$ . Specifically, given a cross-entropy loss $\ell_{\mathrm{ce}}$ and multi-kernel MMD $d_{mk}$ , we minimize the following objective. + +$$ +\begin{array}{l} \min _ {\Phi , W} \left[ \mathcal {L} _ {\mathrm {c e}} + \mathcal {L} _ {\mathrm {d}} ^ {t} \right] = \min _ {\Phi , W} \left[ \frac {1}{n} \sum_ {i = 1} ^ {n} \ell_ {\mathrm {c e}} \left(\mathbf {f} _ {\Theta , \Phi , W} \left(\mathbf {x} _ {i}\right), y _ {i}\right) \right. \tag {3} \\ \left. \right. + d _ {m k} ^ {2} \big (\{\mathbf {f} _ {\Theta , \Phi , W} (\mathbf {x} _ {i}) \} _ {i = 1} ^ {n}, \{\mathbf {f} _ {\Theta , \Phi , W} (\mathbf {x} _ {j, \mathrm {s p t}} ^ {t}) \} _ {j = 1} ^ {m ^ {t}} \big) \big ], \\ \end{array} +$$ + +where $\{\mathbf{x}_{j,\mathrm{spt}}^t\}_{j = 1}^m = S_{\mathrm{spt}}^t$ . Then at each time $t\in T_k^\prime$ , we estimate the empirical mean and covariance of training samples $S$ for each class $c\in \mathcal{V}$ using $\mathbf{h}_{\Phi}\circ \mathbf{f}_{\Theta}$ [29], + +$$ +\hat {\boldsymbol {\mu}} _ {c} ^ {t} = \frac {1}{n _ {c}} \sum_ {i: y _ {i} = c} \mathbf {h} _ {\Phi} \circ \mathbf {f} _ {\Theta} \left(\mathbf {x} _ {i}\right), \quad \hat {\boldsymbol {\Sigma}} ^ {t} = \frac {1}{n} \sum_ {c = 1} ^ {C} \hat {\boldsymbol {\Sigma}} _ {c} ^ {t}, \tag {4} +$$ + +where $n_c$ is the number of samples $S$ for class $c$ , and + +$$ +\hat {\boldsymbol {\Sigma}} _ {c} ^ {t} = \sum_ {i: y _ {i} = c} ^ {n} \left(\mathbf {h} _ {\Phi} \circ \mathbf {f} _ {\Theta} \left(\mathbf {x} _ {i}\right) - \hat {\boldsymbol {\mu}} _ {c} ^ {t}\right) \left(\mathbf {h} _ {\Phi} \circ \mathbf {f} _ {\Theta} \left(\mathbf {x} _ {i}\right) - \hat {\boldsymbol {\mu}} _ {c} ^ {t}\right) ^ {\top}. +$$ + +Note that the adapter $\mathbf{h}_{\Phi}$ is updated by the training objective in Eq. (3) at each time $t\in T_k^{\prime}$ . + +Virtual OOD Generation. We generate virtual OOD samples based on the updated ID features $\mathbf{h}_{\Phi} \circ \mathbf{f}_{\Theta}$ at each time $t \in T_k'$ . Motivated by [8, 29], we also assume that adapted class-conditional ID distribution $D_{\mathbf{h}_{\Phi} \circ \mathbf{f}_{\Theta}(X_{\mathrm{I}}) | Y_{\mathrm{I}} = c}^{t}$ is similar to a multivariate Gaussian distribution, i.e., + +$$ +D _ {\mathbf {h} _ {\Phi} \circ \mathbf {f} _ {\Theta} (X _ {\mathrm {I}}) | Y _ {\mathrm {I}} = c} ^ {t} \approx \mathcal {N} \left(\hat {\mu} _ {c} ^ {t}, \hat {\Sigma} ^ {t}\right), +$$ + +which implies that we can sample virtual OOD samples $Z_{c}^{t}$ at the adapted feature space $\mathcal{Z} = \mathbf{h}_{\Phi}\circ \mathbf{f}_{\Theta}(\mathcal{X})\subset \mathbb{R}^{\tilde{d}}$ to each class $c$ in the $\delta$ -likelihood region, i.e., $Z_{c}^{t}$ is sampled from + +$$ +\left\{\mathbf {z} _ {c} ^ {t} \mid \frac {A}{| \hat {\boldsymbol {\Sigma}} | ^ {1 / 2}} \exp \left(\left(\mathbf {z} _ {c} ^ {t} - \hat {\boldsymbol {\mu}} _ {c} ^ {t}\right) \hat {\boldsymbol {\Sigma}} ^ {- 1} \left(\mathbf {z} _ {c} ^ {t} - \hat {\boldsymbol {\mu}} _ {c} ^ {t}\right)\right) < \delta \right\}, \tag {5} +$$ + +where $A = 1 / (2\pi)^{\tilde{d} /2}$ and $\delta$ is a small constant to ensure that the sampled OOD samples $Z_{c}^{t}$ are near the estimated class boundary in the adapted feature space $\mathcal{Z}$ . + +Inner Uncertainty Regularization. By the above steps, at each time $t \in T_k'$ , we obtained the adapting ID information and the virtual OOD samples at the adapted feature space $\mathcal{Z}$ . Now we add an extra regularization term such that the classifier $\mathbf{c}_W$ can classify the adapted ID samples and virtual OOD samples in the adapted feature space $\mathcal{Z}$ . Specifically, the regularization term [8] is shown in following, + +$$ +\begin{array}{l} \mathcal {L} _ {\mathrm {o o d}} ^ {t} = \frac {1}{C} \sum_ {c = 1} ^ {C} \mathbb {E} _ {\mathbf {z} \sim \mathcal {Z} _ {c} ^ {t}} \left[ - \log \frac {1}{1 + \exp^ {s (\mathbf {z} ; \mathbf {c} _ {W})}} \right] \tag {6} \\ + \mathbb {E} _ {\mathbf {x} \sim S _ {\mathrm {s p t}} ^ {t}} \left[ - \log \frac {\exp^ {s (\mathbf {x} ; \mathbf {f} _ {W , \Phi , \Theta})}}{1 + \exp^ {s (\mathbf {x} ; \mathbf {f} _ {W , \Phi , \Theta})}} \right], \\ \end{array} +$$ + +where the score function $s$ is introduced in Eq. (2). Therefore, we obtain the optimization problem for inner tasks by combining Eq. (3) and (6), i.e., for a parameter $\lambda > 0$ , + +$$ +\min _ {W, \Phi} \mathcal {L} ^ {t} = \min _ {W, \Phi} \left[ \mathcal {L} _ {\mathrm {c e}} + \mathcal {L} _ {\mathrm {d}} ^ {t} + \lambda \mathcal {L} _ {\mathrm {o o d}} ^ {t} \right]. \tag {7} +$$ + +Note that at the earlier training stage, we optimize $\Phi$ , $W$ only by using Eq. (3) so that a good estimation of ID distribution can be learned. Specifically, following VOS [8], we maintained a ID class-conditional queue $|Q_y|$ for each class $y \in \mathcal{V}$ for continuous online estimation of $\hat{\mu}_c^t$ and $\hat{\Sigma}^t$ . The uncertainty regularization (Eq. (7)) is introduced in the middle of the training (i.e., at a certain starting epoch $E$ ). + +# 4.2. Learning A Meta-representation + +Outer-loop Training. In Section 4.1, the inner training task only involves updating the adapter $\mathbf{h}_{\Phi}$ and classifier $\mathbf{c}_W$ while keeping the feature extractor $\mathbf{f}_{\Theta}$ fixed. In the outer loop, we target on updating $\mathbf{f}_{\Theta}$ corresponding to fixed $\Phi$ , $W$ given in the inner tasks at each time $t \in T_k'$ . Firstly, considering harnessing the knowledge transfer between continuous shifting distributions during time period $T_k'$ , we minimize the distribution discrepancy across the time period $T_k'$ : let $T_k' = \{t_1', t_2', \dots, t_l'\}$ with $t_1' < t_2' < \dots < t_l'$ , then + +$$ +\mathcal {L} _ {\mathrm {q r y}} = \max _ {i \in [ l - 1 ]} d _ {m k} ^ {2} \left(\mathbf {f} _ {\Theta , \Phi , W} \left(S _ {\mathrm {q r y}} ^ {t _ {i + 1} ^ {\prime}}\right), \mathbf {f} _ {\Theta , \Phi , W} \left(S _ {\mathrm {q r y}} ^ {t _ {i} ^ {\prime}}\right)\right), \tag {8} +$$ + +where $\mathbf{f}_{\Theta ,\Phi ,W}(S_{\mathrm{qry}}^{t_i'}) = \{\mathbf{f}_{\Theta ,\Phi ,W}(\mathbf{x}_{j,\mathrm{qry}}^{t_i'})\}_{j = 1}^{m't_i'}$ here we set $S_{\mathrm{qry}}^{t_i'} = \{\mathbf{x}_{j,\mathrm{qry}}^{t_i'}\}_{j = 1}^{m't_i}$ . Intuitively, $\mathcal{L}_{\mathrm{qry}}$ estimates the discrepancies of continuously shifting distributions across the + +Algorithm 1. MOL in Training Process +Input: ID training samples $S$ and $\{S^t\}_{t\in T_k}$ ; learning rates $\alpha ,\beta$ randomly initialized model $\mathbf{f}_{W,\Phi ,\Theta} = \mathbf{c}_W\circ \mathbf{h}_{\Phi}\circ \mathbf{f}_{\Theta}$ while not done do Randomly initialized adapter $\mathbf{h}_{\Phi}$ and classifier $\mathbf{c}_W$ Randomly sample $T_{k}^{\prime} = \{t_{1}^{\prime},t_{2}^{\prime},\dots,t_{l}^{\prime}\}$ from $T_{k}$ and sample support and query sets $\mathbf{S}_{\mathrm{spt}}$ and $\mathbf{S}_{\mathrm{qry}}$ from $\{S^t\}_{t\in T_k'}$ for $i = 1$ to $l$ do Estimate $\hat{\mu}_c^{t_i}$ and $\hat{\Sigma}^{t_i}$ by using $S$ and Eq. (4); Sample virtual OOD samples $Z_{c}^{t_{i}}$ by Eq. (5); Compute $\mathcal{L}^{t_i}$ using $S,S_{\mathrm{spt}}^{t_i}$ and $Z_{c}^{t_{i}}$ by Eq. (7); Update parameters: $(\Phi ,W)_{t_i + 1} = (\Phi ,W)_{t_i} - \alpha \nabla \mathcal{L}^{t_i}$ end for Compute $\mathcal{L}_{\mathrm{meta}}$ using $S$ and $\mathbf{S}_{\mathrm{qry}}$ by Eq. (9); Update parameters: $\Theta = \Theta -\beta \nabla \mathcal{L}_{\mathrm{meta}}$ end while Output: initial model $G_{\gamma}$ $(\mathbf{x};s,\mathbf{f}_{\Theta ,\Phi ,W})$ by Eq. (1) meta-representation $\mathbf{f}_{\Theta}$ + +Algorithm 2. MOL in Testing Process +Input: ID training samples $S$ and $\{S^t\}_{t\in T_K^-}$ ; learning rates $\alpha, \beta$ ; meta-representation $\mathbf{f}_{\Theta}$ ; score function introduced in Eq. (2). while not done do +Randomly initialized adapter $\mathbf{h}_{\Phi}$ and classifier $\mathbf{c}_W$ ; +for $i = K$ to $N$ do +Estimate $\hat{\mu}_c^{t_i}$ and $\hat{\Sigma}^{t_i}$ by using $S$ and Eq. (4); +Sample virtual OOD samples $Z_c^{t_i}$ by Eq. (5); +Compute $\mathcal{L}^{t_i}$ using $S$ , $S^{t_i}$ and $Z_c^{t_i}$ by Eq. (7); +Update parameters: $(\Phi, W)_{t_{i+1}} = (\Phi, W)_{t_i} - \alpha \nabla \mathcal{L}^{t_i}$ ; +end for +Output: model $G_{\gamma}(\mathbf{x}; s, \mathbf{f}_{\Theta, \Phi, W})$ by Eq. (1). end while + +time period $T_{k}^{\prime}$ . Then, the optimization issue in outer-loop training can be represented as follows: + +$$ +\begin{array}{l} \min _ {\Theta} \mathcal {L} _ {\text {m e t a}} = \min _ {\Theta} \left[ \mathcal {L} _ {\text {c e}} + \mathcal {L} _ {\text {q r y}} \right. \\ \left. + \frac {1}{\left| T _ {k} ^ {\prime} \right|} \sum_ {t \in T _ {k} ^ {\prime}} \left(\mathcal {L} _ {\mathrm {d}} ^ {t} + \lambda \mathcal {L} _ {\mathrm {o o d}} ^ {t}\right) \right], \tag {9} \\ \end{array} +$$ + +where $\mathcal{L}_{\mathrm{d}}^{t}$ and $\mathcal{L}_{\mathrm{ood}}^{t}$ are computed by using the samples $S_{\mathrm{qry}}^{t}$ in the query set $\mathbf{S}_{\mathrm{qry}}$ . + +In Eq. (9), the inner tasks (corresponding to $\mathcal{L}_{\mathrm{d}}^{t} + \lambda \mathcal{L}_{\mathrm{odd}}^{t}$ ) across all time period $T_{k}^{\prime}$ are fed as one input (corresponding to $\sum_{t\in T_k'}\left(\mathcal{L}_{\mathrm{d}}^t +\lambda \mathcal{L}_{\mathrm{odd}}^t\right) / |T_k^{\prime}|$ ) in the outer-loop training. Thus, we are able to learn a good initialization of meta-representation $\Theta$ such that: when encountering a new distribution during testing, a few updating steps of $\Phi ,W$ result in a good performance. + +Meta-testing. In the testing process, when exposed to previously unseen shifting distributions $D_{X_1Y_1}^t$ (where $t \in T_K^{-}$ ), we only need to fine-tune the adapter $\mathbf{h}_{\Phi}$ and classifier $\mathbf{c}_W$ on the new test samples $S^t$ (where $t \in T_K^{-}$ ), while + +keeping the meta-representation $\mathbf{f}_{\Theta}$ fixed. This strategy enables fast adaptation by updating the lightweight classifier and adapter, which is useful for real-world online applications like self-driving agents. Furthermore, by incorporating the score function in Eq. (2), we can obtain an OOD detection model $g_{t}$ , while updating $\mathbf{h}_{\Phi}$ and $\mathbf{c}_W$ at each time $t \in T_K^-$ during the testing process. + +# 5. Experiments + +# 5.1. Adaptive OOD Benchmark Construction + +For CAOOD evaluation, we construct 3 benchmarks (e.g., using Rotation MNIST, Cifar Corruption datasets as ID datasets) derived from commonly used static OOD benchmarks (e.g., MNIST, Cifar). Rotation MNIST and Corruption datasets are frequently used in continuous domain adaptation [53, 56]. In practical applications, rotation can replicate shifts arising from camera positions, while corruptions mimic various weather conditions (e.g., fog, snow) and movements (e.g., motion). In CAOOD, we evaluate both ID accuracy and OOD detection effectiveness. Dataset details are provided in the Appendix. + +Rotation MNIST [5]. This dataset has MNIST digits with various rotations from $[0,180^{\circ}]$ , and for each rotation, there are 60,000 training images. In our benchmark, we use Rotation MNIST (R-MNIST) as the ID training dataset and evaluate the OOD detection performance on Rotation NOTMNIST (R-NOTMNIST) and Rotation Cifar10bw (R-Cifar10bw). There are no semantics overlaps between the ID and OOD datasets. + +In our proposed MOL protocol, we consider images with rotation $0^{\circ}$ as the labeled original training samples $S$ , and images from rotation $(0,180^{\circ}]$ as continuously shifting distributions over the whole time period $(0,T]$ , i.e., $\{S^t\}_{t\in T}$ . In meta-training, we use images from rotation $(0 - 60^{\circ}]$ as $\{S^t\}_{t\in T_k}$ , and randomly sample $\mathbf{S}_{\mathrm{spt}}$ , $\mathbf{S}_{\mathrm{qry}}$ of length 10. During meta-testing, we update our model online for rotation $\{S_{120^{\circ}},S_{126^{\circ}},i\dots S_{174^{\circ}}\}$ , i.e., $\{S^t\}_{T_K^-}$ and for each rotation, we only use 100 training samples for adaptation. + +Cifar10C. This dataset consists of 15 types of corruptions (e.g., fog, brightness, motion, noise) with each demonstrating 5 levels of severity. We use Cifar10C as the ID data and test on two near OOD datasets applying the same shifting distribution: TinyimageNetC, and Cifar100C. Following the OOD benchmark literature [63], we create TinyimageNetC from a subset of the Tinyimagenet [49] where 1207 images overlap semantic labels with Cifar10 are removed. + +In our protocol, we take clean images from Cifar10 as original training samples $S$ , and consider images with various corruptions from Cifar10C as samples come from shifting distributions. Specifically, we design the continuous shifting distributions by gradually changing the severity across all corruption types, for example: + +Table 1: OOD benchmarks used in our evaluation, including CAOD datasets, near OOD, and far OOD datasets. + +
ID DatasetCAOODNear OODFar OOD
R-MNISTR-NOTMNISTNOTMNISTCifar10bw
R-Cifar10bw
Cifar10CCifar100CCifar100Textures
TinyimagenetCTinyimageNetLSUN iSUN
Cifar100CCifar10CCifar10Textures
TinyimagenetCTinyimageNetLSUN iSUN
+ +$$ +\underbrace {\cdots , \mathrm {C} _ {t - 1} ^ {5}} _ {\text {t - 1 a n d b e f o r e}} \rightarrow \underbrace {\mathrm {C} _ {t} ^ {1} , \mathrm {C} _ {t} ^ {2} , \mathrm {C} _ {t} ^ {3} , \mathrm {C} _ {t} ^ {4} , \mathrm {C} _ {t} ^ {5} , \mathrm {C} _ {t} ^ {4} , \mathrm {C} _ {t} ^ {3} , \mathrm {C} _ {t} ^ {2} , \mathrm {C} _ {t} ^ {1}} _ {\text {c o r r u p t i o n t y p e t , c h a n g i n g g r a d u a l l y}} \rightarrow \underbrace {\mathrm {C} _ {t + 1} ^ {1} , \mathrm {C} _ {t + 1} ^ {2} , \cdots} _ {\text {t + 1 a n d o n}} +$$ + +In meta-training, we randomly sample $\mathbf{S}_{\mathrm{spt}}$ , $\mathbf{S}_{\mathrm{qry}}$ of length 10 (i.e., $|T_k'| = 10$ ), from the first 7 corruptions of 63 continuously shifting distributions, i.e., $\{S^t\}_{t \in T_k}$ , $|T_k| = 63$ . In meta-testing, we adapt our model to a trajectory of length 10 that is randomly sampled from the last 7 corruptions and evaluate on unseen test images from the last 7 corruptions (i.e., frost, fog, brightness, contrast, elastic transform, pixelate, jpeg compression). Similarly, we only had access to 100 training samples in meta-testing. + +Cifar100C [16]. This dataset is a variant of Cifar10C by applying the same corruptions to Cifar100. We used Cifar100C as the ID dataset and two near OOD datasets with the same continuous shifting distributions: Cifar10C and TinyImageNetC. We re-create TinyImageNetC after 2505 images sharing the same classes with Cifar100 have been removed [63]. For the MOL protocol, we applied the same training and testing fashion as used in Cifar10C. + +Standard OOD Datasets. In addition, we evaluate our method's OOD detection performance on commonly used OOD datasets from a static distribution, including Cifar10 and Cifar100 [26], TinyImageNet [49], Textures [27], LSUN-Resize, LSUN-Crop [66], and iSUN [61]. Table 1 summarizes evaluated OOD detection benchmarks. + +# 5.2. Baselines and Metrics + +We compare our method with comprehensive OOD detection baselines including Maximum Softmax Probability [17], ODIN [32], Mahalanobis distance [29], energy score [34], Gram Metrics [45], Gradnorm [19], and the recent VOS [8], KNN [47] and LogitNorm [60]. To apply the above static OOD detection baselines in CAOOD, we use three different training/adapting schemes as follows. + +Direct Test. The model is trained on the labeled original training samples $S$ and then directly test on continuously shifting $\{S^t\}_{t\in T_K^-}$ for OOD detection with no adaptation. + +Simple Adaptive. During training, the model is trained on the labeled original training samples $S$ . During testing, we finetune the classifier of the model to adapt to continuously + +Table 2: Main Results on Rotation MNIST. $\uparrow$ (or $\downarrow$ ) indicates greater (or smaller) values are preferred. For each comparable method, we report results on Direct Test / Simple Adaptive / Domain Adaptation. Only Direct Test results are reported for Gram and KNN, only Direct Test and Simple Adaptive results are reported for VOS and LogitNorm. The bold and * represent the best and second best performance and the shadow part marks our method. + +
MethodRotation NOTMNISTRotation Cifar10bwAverageID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
MSP76.9 / 75.9 / 62.371.9 / 70.4 / 87.690.1 / 89.4 / 68.855.6 / 48.5 / 83.683.5 / 82.6 / 65.664.8 / 59.5 / 85.625.6 / 28.3 / 27.2
ODIN63.6 / 76.7 / 30.885.2 / 72.6 / 56.787.3 / 88.1 / 67.658.2 / 50.9 / 83.975.5 / 82.4 / 49.271.7 / 61.8 / 70.325.6 / 28.3 / 27.2
Mahalanobis61.2 / 75.4 / 32.986.1 / 75.1 / 56.989.3 / 90.1 / 66.758.1 / 49.5 / 80.875.3 / 82.8 / 49.872.1 / 62.3 / 68.925.6 / 28.4 / 27.7
Energy92.6 / 91.7 / 72.736.1 / 39.7 / 76.197.5 / 95.9 / 69.112.6 / 19.9 / 85.295.1 / 93.8 / 70.924.4 / 29.8 / 80.725.6 / 28.3 / 27.2
Gram96.1*10.698.9*4.6*97.5*7.625.6
VOS86.7 / 93.557.6 / 32.392.7 / 96.731.0 / 16.489.7 / 95.144.3 / 24.427.7 / 30.9
LogitNorm84.0 / 94.046.2 / 29.797.7 / 99.010.5 / 4.590.0 / 96.528.3 / 17.124.7 / 31.5*
KNN95.716.591.425.093.520.824.9
MOL96.513.9*98.9*9.297.711.5*35.6
+ +Table 3: Main Results on Cifar10 corruption. $\uparrow$ (or $\downarrow$ ) indicates greater (or smaller) values are preferred. For each comparable method, we report results on Direct Test / Simple Adaptive / Domain Adaptation. Only Direct Test results are reported for Gram, Gradnorm, and KNN, only Direct Test and Simple Adaptive results are reported for VOS and LogitNorm. The bold and * represent the best performance and the shadow part marks our method. + +
MethodCifar100CTinyImagenetCAverageID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
MSP53.2 / 62.2 / 54.894.3 / 91.6 / 92.959.7 / 64.0 / 52.992.5 / 91.2 / 94.956.5 / 63.1 / 53.893.4 / 91.4 / 93.938.5 / 56.2 / 35.6
ODIN46.1 / 61.3 / 55.296.5 / 91.9 / 93.440.3 / 62.9 / 52.099.1 / 91.5 / 94.943.2 / 62.1 / 53.697.8 / 91.7 / 94.238.1 / 55.6 / 35.2
Mahalanobis46.8 / 63.6 / 55.196.7 / 91.3 / 93.447.0 / 66.0 / 53.698.1 / 90.6 / 93.946.9 / 64.8 / 54.497.4 / 90.9 / 93.738.5 / 56.2 / 35.6
Energy52.7 / 60.8 / 56.594.4 / 91.4 / 93.761.5 / 65.0 / 60.891.6 / 89.0 / 94.657.1 / 62.9 / 58.793.0 / 90.2 / 94.238.5 / 52.9 / 35.6
Gram55.289.766.582.560.986.1*38.1
Gradnorm29.597.241.396.535.496.938.5
VOS52.6 / 53.695.7 / 96.557.3 / 59.997.2 / 97.154.9 / 56.896.5 / 96.825.9 / 31.7
LogitNorm56.4 / 65.3*94.5 / 88.9*61.9 / 67.6*92.6 / 85.959.1 / 66.4*93.6 / 87.443.5 / 59.1*
KNN54.194.457.793.555.994.044.2
MOL69.786.371.485.6*70.685.964.1
+ +shifting $\{S^t\}_{t\in T_K^-}$ dynamically and test their performance. Specifically, the classifier is updated using our proposed meta-testing strategy without virtual OOD generation and uncertainty regularization (i.e., by using Eq. 3). + +Domain Adaptation. The model is trained using classic domain adaptation techniques DAN [36]. Specifically, in the training process, we train the model offline by viewing $S$ as the source domain and all shifting training samples $\{S^t\}_{t \in T_k}$ available as the target domain. During testing, we finetune the classifier of the model to adapt to continuously shifting $\{S^t\}_{t \in T_K^-}$ dynamically and test their performance (Eq. (3)). By doing so the Domain Adaptation strategy violates the CAOD setting during training. + +Note that for Gram Metrics, Gradnorm, and KNN, only the Direct Test results are reported because their scoring functions are calculated based on feature representations across all layers, which demands a finetuning on the whole model during testing. For VOS and LogitNorm, only Direct Test and Simple Adaptive results are reported, as we found it difficult to train them with Domain Adaptation strategy. + +Evaluation Metrics. For OOD detection evaluation, we report 1) the area under the receiver operating characteristic curve (AUROC), which measures the model's capacity to distinguish ID and OOD samples based on varying thresholds of the predicted confidence scores; and 2) the false positive rate (FPR95) of OOD samples when the true positive rate of ID samples is fixed at $95\%$ , which measures the percentage of OOD samples that are incorrectly classified as ID samples when the model's sensitivity to ID samples is high. For evaluating the ID classification, we report the commonly used accuracy. + +# 5.3. Implementation Details + +On the R-MNIST dataset, we use LeNet as the backbone for all models. As for Cifar10C and Cifar100C datasets, we use WideResNet as the backbone. Note that in our method, the last fully connected layers of LeNet and WideResNet are removed for learning meta-representation during training. We set the uncertainty regularization balancing term $\lambda$ as 0.015 for R-MNIST, and 0.1 for two CifarC datasets. The + +Table 4: Main Results on Cifar100 corruption. $\uparrow$ (or $\downarrow$ ) indicates greater (or smaller) values are preferred. For each comparable method, we report results on Direct Test / Simple Adaptive / Domain Adaptation (DA). Only Direct Test results are reported for Gram, Gradnorm, and KNN, only Direct Test and Simple Adaptive results are reported for VOS and LogitNorm. The bold and * represent the best performance and the shadow part marks our method. + +
MethodTinyImagenetCCifar10CAverageID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
MSP50.9 / 61.3 / 58.194.8 / 91.3 / 92.558.2 / 64.0 / 61.292.9 / 91.2 / 91.354.6 / 62.7* / 59.793.4 / 91.3 / 91.927.8 / 41.4 / 37.7
ODIN49.1 / 59.7 / 55.595.5 / 91.4 / 93.641.8 / 63.5 / 60.298.0 / 90.8* / 91.645.5 / 61.6 / 57.996.8 / 91.1* / 92.227.8 / 41.4 / 37.7
Mahalanobis48.597.140.499.044.598.127.8
Energy50.7 / 58.0 / 61.6*94.9 / 92.1 / 91.0*58.7 / 63.6* / 61.092.9 / 91.4 / 92.654.7 / 60.8 / 61.393.9 / 91.8 / 91.827.8 / 41.4 / 37.7
Gram47.195.949.695.648.495.827.8
VOS49.9 / 52.196.0 / 96.352.6 / 54.897.7 / 98.051.3 / 53.596.9 / 97.226.1 / 43.1*
LogitNorm53.0 / 58.394.1 / 92.258.8 / 63.193.2 / 91.955.9 / 60.793.7 / 92.023.4 / 38.5
KNN51.795.150.094.950.995.022.9
MOL69.488.763.189.066.388.957.4
+ +![](images/8e8faf2e11dddf91e67a7a1d03a739e9d2d19c88f7b9cb5dfdb2fcc91c478a9d.jpg) +Figure 3: The ID classification (a) and OOD detection performance (b-c) on R-MNIST benchmark over continuously shifting distributions. Our method achieved the best performance on all unseen distributions, i.e., the pink line. + +![](images/405aa6acccfb98056eb25cd8223fc29799c06afdd5810045d20a0229624c4e55.jpg) + +![](images/a52959edae6a3bd0f9103c4d107ee82d0cc4beba612dcc2416c5c94d9e21a8f5.jpg) + +Table 5: Average results over 10 randomly sampled trajectories on R-MNIST. + +
MethodR-NOTMNISTR-Cifar10bwID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
Fixed97.913.998.99.235.6
Sampled97.7 ±0.413.6 ±0.898.8 ±0.49.6 ±0.736.7 ±1.4
+ +Table 6: Ablation study on R-MNIST, where w/o $\mathcal{L}_{\mathrm{ood}}$ and w/o $\mathcal{L}_{\mathrm{qry}}$ are variants trained without $\mathcal{L}_{\mathrm{ood}}$ and $\mathcal{L}_{\mathrm{qry}}$ . E indicates the adding point of $\mathcal{L}_{\mathrm{ood}}$ , e.g., $1/2$ indicates adding $\mathcal{L}_{\mathrm{ood}}$ halfway through training. + +
MethodR-NOTMNISTR-Cifar10bwID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
w/o Lood94.134.997.612.234.2
w/o Lqry93.935.196.914.332.2
E = 1/399.77.499.95.628.7
E = 1/298.010.499.18.730.1
E = 2/396.513.998.99.235.6
E = 4/595.315.595.216.335.9
+ +learning rates in inner/outer loops are set as 0.1/0.01 for R-MNIST, and 0.3/0.03 for two CIFarC datasets, respectively. We use SGD with 0.9 momentum and $5 \times 10^{-4}$ weight decay. On each OOD benchmark, all methods are trained us- + +ing the same backbones with the same number of epochs. + +# 5.4. Experimental Results + +Results on R-MNIST. Table 2 summarizes the ID classification and OOD detection results on R-MNIST. The baseline results show that most existing static OOD detection methods cannot handle ID classification and OOD detection when test samples compass continuous distribution shifts. By using an alternate scheme when we fine-tune the model's classifier during testing (i.e., Simple Adaptive), the comparable methods improved around $2.7\%$ in ID accuracy and reduced from $5.3\%$ to $19.3\%$ in FPR95 across all baselines. Such improvement endorses the dynamic adaptation of the OOD detection model when test samples come from continuously shifting distribution. + +When examining the performance of the Domain Adaptation strategy, results show that ID accuracy improved over the Direct Test baselines, however, the OOD detection performance dropped heavily, from $17.9\%$ to $26.3\%$ across all methods in AUROC. In contrast to the Domain Adaptation strategy, our method obtained superior performance (ID accuracy: $35.6\%$ , AUROC: $97.7\%$ ) by respecting the continuous shifting characteristic of test distributions. Note that although Gram [45] obtained the best results in FPR95, their ID accuracy ( $10\%$ lower than our method) questioned the + +reliability of the OOD detection performance in CAOOD. + +Results on Cifar Corruption. Table 3 and 4 show the OOD detection results on Cifar10C and Cifar100C. Results show that MOL achieved the best performance on both Cifar corruption benchmarks. On Cifar10C, we outperformed Direct Test, Simple Adaptive, and Domain Adaptation strategies by $25.6\%$ , $7.9\%$ , and $28.5\%$ in ID classification respectively. For OOD detection, we outperformed most comparable methods and adaptation strategies. Our AUROC outperformed the second-best result (i.e., Simple Adaptive LogitNorm) by $4.2\%$ . On Cifar100C, we improved the 3 adaptation strategies by $29.6\%$ , $16.0\%$ , and $19.7\%$ respectively in ID accuracy, while maintaining the best average OOD detection performance when compared to all other methods. Note that in our reproduction, Gram shows a catastrophic OOD performance drop and Gradnorm obtained a $100\%$ in FPR95 when tested on the Cifar100C benchmark, which indicates the instability of their scoring functions using gradients/features across all layers when applied in CAOOD. + +Performance on Continuously Shifting Distribution. Figure 3 shows the ID classification and AUROC over distributions on the Rotation MNIST benchmark. It is clear to see that the OOD detection performance of VOS and Energy decreased when the distribution continues to shift, while our method maintained a good OOD detection (i.e., the purple line). This further endorses our method's superiority in addressing the CAOOD problem by learning to quickly adapt to newly arriving test samples with shifting distributions. + +Discussion on the impact of Discretization. Theoretically, modeling in continuous time intervals requires infinite samples, making it unrealistic. As such discretization (using finite samples to simulate infinite samples) is a common way to address continuous domain adaptation [56, 2]. CIDA [53] employs closed intervals which uniformly sample finite time points from these intervals and obtain training data for each sampled time point. Following CIDA, instead of adapting to one fixed discretized trajectory, in meta-training, we adapt to randomly sampled trajectories (i.e., $\mathbf{S}_{\mathrm{spt}}, \mathbf{S}_{\mathrm{qry}}$ ) to approximate from $0^{\circ}$ to $60^{\circ}$ . To further evaluate the impact of discretization on detection accuracy, we evaluate our method on 10 randomly sampled trajectories during testing. Table 5 shows the average results suggesting that the detection performance remains stable across various trajectories (fixed and sampled). + +# 5.5. Ablation Study + +A brief ablation analysis is provided in Table 6. Firstly, we build a variant of our model without $\mathcal{L}_{\mathrm{ood}}$ by taking out the uncertainty regularization term $\mathcal{L}_{\mathrm{ood}}$ so it reduces to focus solely on continuous ID adaptation without synthesizing virtual OOD samples for uncertainty regularization. By doing so the ID accuracy slightly dropped by $1.4\%$ while the OOD detection performance decreases noticeably (3.8% in + +AUROC). Then, we conduct experiments on another variant without $\mathcal{L}_{\mathrm{qry}}$ without the constraint term on distribution discrepancy $\mathcal{L}_{\mathrm{qry}}$ , leading to performance drops on all ID accuracy, AUROC, and FPR95. This reflects that harnessing knowledge transfer between distributions is indispensable to the CAOD problem. Further, we studied the impact on starting point of uncertainty regularization during the whole training process. Results show that an earlier start resulted in a significant drop in ID accuracy while the OOD detection performance is good but meaningless. We suggest that a balance should be identified whenever the ID accuracy is prioritized. More ablations, experimental results, and comparisons about training/testing time refer to the Appendix. + +# 6. Conclusion and Future Works + +OOD detection has achieved great progress while facing challenges in real-world scenarios when test samples exhibit dynamic distribution shifting. Motivated by these challenges, we propose a novel and more realistic CAOD detection and develop an effective method of MOL in addressing this problem. To the best of our knowledge, we are the first to investigate OOD detection under continuous distribution shifts. Our proposal will motivate future works to pursue new methods in addressing real-world OOD detection under continuously shifting distributions. + +# References + +[1] Abhijit Bendale and Terrance Boult. Towards open world recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1893-1902, 2015. +[2] Andreea Bobu, Eric Tzeng, Judy Hoffman, and Trevor Darryll. Adapting to continuously shifting domains. In International Conference on Learning Representations, 2018. +[3] Jiefeng Chen, Yixuan Li, Xi Wu, Yingyu Liang, and Somesh Jha. Atom: Robustifying out-of-distribution detection using outlier mining. In Machine Learning and Knowledge Discovery in Databases. Research Track: European Conference, ECML PKDD 2021, Bilbao, Spain, September 13-17, 2021, Proceedings, Part III 21, pages 430-445. Springer, 2021. +[4] Rui Dai, Yonggang Zhang, Zhen Fang, Bo Han, and Xinmei Tian. Moderately distributional exploration for domain generalization. International Conference on Machine Learning, 2023. +[5] Li Deng. The mnist database of handwritten digit images for machine learning research. IEEE Signal Processing Magazine, 29(6):141-142, 2012. +[6] Jiahua Dong, Yang Cong, Gan Sun, Zhen Fang, and Zhengming Ding. Where and how to transfer: Knowledge aggregation-induced transferability perception for unsupervised domain adaptation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 1(2):1-18, 2021. +[7] Jiahua Dong, Yang Cong, Gan Sun, Bineng Zhong, and Xiaowei Xu. What can be transferred: Unsupervised domain adaptation for endoscopic lesions segmentation. In + +IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4022-4031, June 2020. +[8] Xuefeng Du, Zhaoning Wang, Mu Cai, and Yixuan Li. Vos: Learning what you don't know by virtual outlier synthesis. In International Conference on Learning Representations, 2022. +[9] Thomas Elsken, Benedikt Staffler, Jan Hendrik Metzen, and Frank Hutter. Meta-learning of neural architectures for few-shot learning. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12365-12375, 2020. +[10] Zhen Fang, Yixuan Li, Jie Lu, Jiahua Dong, Bo Han, and Feng Liu. Is out-of-distribution detection learnable? Advances in Neural Information Processing Systems, 35:37199-37213, 2022. +[11] Zhen Fang, Jie Lu, Anjin Liu, Feng Liu, and Guangquan Zhang. Learning bounds for open-set learning. In International Conference on Machine Learning, pages 3122-3132. PMLR, 2021. +[12] Zhen Fang, Jie Lu, Feng Liu, and Guangquan Zhang. Semi-supervised heterogeneous domain adaptation: Theory and algorithms. IEEE Transactions on Pattern Analysis and Machine Intelligence, 45(1):1087-1105, 2023. +[13] Chelsea Finn, Pieter Abbeel, and Sergey Levine. Model-agnostic meta-learning for fast adaptation of deep networks. In International Conference on Machine Learning, pages 1126–1135. PMLR, 2017. +[14] Yaroslav Ganin, Evgeniya Ustinova, Hana Ajakan, Pascal Germain, Hugo Larochelle, François Laviolette, Mario Marchand, and Victor Lempitsky. Domain-adversarial training of neural networks. The journal of machine learning research, 17(1):2096-2030, 2016. +[15] Arthur Gretton, Karsten M Borgwardt, Malte J Rasch, Bernhard Scholkopf, and Alexander Smola. A kernel two-sample test. The Journal of Machine Learning Research, 13(1):723-773, 2012. +[16] Dan Hendrycks and Thomas Dietterich. Benchmarking neural network robustness to common corruptions and perturbations. In International Conference on Learning Representations, 2019. +[17] Dan Hendrycks and Kevin Gimpel. A baseline for detecting misclassified and out-of-distribution examples in neural networks. In International Conference on Learning Representations, 2016. +[18] Dan Hendrycks, Mantas Mazeika, and Thomas Dietterich. Deep anomaly detection with outlier exposure. In International Conference on Learning Representations, 2018. +[19] Rui Huang, Andrew Geng, and Yixuan Li. On the importance of gradients for detecting distributional shifts in the wild. Advances in Neural Information Processing Systems, 34:677-689, 2021. +[20] Rui Huang and Yixuan Li. Mos: Towards scaling out-of-distribution detection for large semantic space. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8710-8719, 2021. +[21] Xiaowei Huang, Daniel Kroening, Wenjie Ruan, James Sharp, Youcheng Sun, Emese Thamo, Min Wu, and Xinping + +Yi. A survey of safety and trustworthiness of deep neural networks: Verification, testing, adversarial attack and defence, and interpretability. Computer Science Review, 37:100270, 2020. +[22] Conor Igoe, Youngseog Chung, Ian Char, and Jeff Schneider. How useful are gradients for ood detection really? arXiv preprint arXiv:2205.10439, 2022. +[23] Taewon Jeong and Heeyoung Kim. Ood-maml: Meta-learning for few-shot out-of-distribution detection and classification. Advances in Neural Information Processing Systems, 33:3907-3916, 2020. +[24] KJ Joseph, Salman Khan, Fahad Shahbaz Khan, and Vineeth N Balasubramanian. Towards open world object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5830-5840, 2021. +[25] KJ Joseph, Jathushan Rajasegaran, Salman Khan, Fahad Shahbaz Khan, and Vineeth N Balasubramanian. Incremental object detection via meta-learning. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(12):9209-9216, 2021. +[26] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images. 2009. +[27] Gustaf Kylberg. Kylberg texture dataset v. 1.0. 2011. +[28] Balaji Lakshminarayanan, Alexander Pritzel, and Charles Blundell. Simple and scalable predictive uncertainty estimation using deep ensembles. Advances in neural information processing systems, 30, 2017. +[29] Kimin Lee, Kibok Lee, Honglak Lee, and Jinwoo Shin. A simple unified framework for detecting out-of-distribution samples and adversarial attacks. Advances in neural information processing systems, 31, 2018. +[30] KIMIN LEE, Kibok Lee, Honglak Lee, and Jinwoo Shin. Training confidence-calibrated classifiers for detecting out-of-distribution samples. In International Conference on Learning Representations, 2018. +[31] Yi Li and Nuno Vasconcelos. Background data resampling for outlier-aware classification. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13218-13227, 2020. +[32] Shiyu Liang, Yixuan Li, and R Srikant. Enhancing the reliability of out-of-distribution image detection in neural networks. In International Conference on Learning Representations, 2018. +[33] Ziqian Lin, Sreya Dutta Roy, and Yixuan Li. Mood: Multi-level out-of-distribution detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 15313-15323, 2021. +[34] Weitang Liu, Xiaoyun Wang, John Owens, and Yixuan Li. Energy-based out-of-distribution detection. Advances in neural information processing systems, 33:21464-21475, 2020. +[35] Ziwei Liu, Zhongqi Miao, Xingang Pan, Xiaohang Zhan, Dahua Lin, Stella X Yu, and Boqing Gong. Open compound domain adaptation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12406-12415, 2020. + +[36] Mingsheng Long, Yue Cao, Jianmin Wang, and Michael Jordan. Learning transferable features with deep adaptation networks. In International Conference on Machine Learning, pages 97-105. PMLR, 2015. +[37] Mingsheng Long, Han Zhu, Jianmin Wang, and Michael I Jordan. Deep transfer learning with joint adaptation networks. In International Conference on Machine Learning, pages 2208-2217. PMLR, 2017. +[38] Andrey Malinin and Mark Gales. Predictive uncertainty estimation via prior networks. Advances in neural information processing systems, 31, 2018. +[39] Yifei Ming, Ying Fan, and Yixuan Li. Poem: Out-of-distribution detection with posterior sampling. In International Conference on Machine Learning, pages 15650-15665. PMLR, 2022. +[40] Yifei Ming, Yiyou Sun, Ousmane Dia, and Yixuan Li. Cider: Exploiting hyperspherical embeddings for out-of-distribution detection. arXiv preprint arXiv:2203.04450, 2022. +[41] Yifei Ming, Hang Yin, and Yixuan Li. On the impact of spurious correlation for out-of-distribution detection. In Proceedings of the AAAI Conference on Artificial Intelligence, pages 10051-10059, 2022. +[42] Sinno Jialin Pan, Ivor W Tsang, James T Kwok, and Qiang Yang. Domain adaptation via transfer component analysis. IEEE Transactions on Neural Networks, 22(2):199-210, 2010. +[43] Juan-Manuel Perez-Rua, Xiatian Zhu, Timothy M Hospedales, and Tao Xiang. Incremental few-shot object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13846-13855, 2020. +[44] Shafin Rahman, Salman H Khan, and Fatih Porikli. Zero-shot object detection: Joint recognition and localization of novel concepts. International Journal of Computer Vision, 128:2979-2999, 2020. +[45] Chandramouli Shama Sastry and Sageev Oore. Detecting out-of-distribution examples with gram matrices. In International Conference on Machine Learning, pages 8491-8501. PMLR, 2020. +[46] Yiyou Sun, Chuan Guo, and Yixuan Li. React: Out-of-distribution detection with rectified activations. Advances in Neural Information Processing Systems, 34:144-157, 2021. +[47] Yiyou Sun, Yifei Ming, Xiaojin Zhu, and Yixuan Li. Out-of-distribution detection with deep nearest neighbors. In International Conference on Machine Learning, pages 20827-20840. PMLR, 2022. +[48] Jihoon Tack, Sangwoo Mo, Jongheon Jeong, and Jinwoo Shin. Csi: Novelty detection via contrastive learning on distributionally shifted instances. Advances in neural information processing systems, 33:11839-11852, 2020. +[49] Antonio Torralba, Rob Fergus, and William T Freeman. 80 million tiny images: A large data set for nonparametric object and scene recognition. IEEE Transactions on pattern analysis and machine intelligence, 30(11):1958-1970, 2008. +[50] Joost Van Amersfoort, Lewis Smith, Yee Whye Teh, and Yarin Gal. Uncertainty estimation using a single deep de + +terministic neural network. In International Conference on Machine Learning, pages 9690-9700. PMLR, 2020. +[51] Sachin Vernekar, Ashish Gaurav, Vahdat Abdelzad, Taylor Denouden, Rick Salay, and Krzysztof Czarnecki. Out-of-distribution detection in classifiers via generation. arXiv preprint arXiv:1910.04241, 2019. +[52] Ricardo Vilalta and Youssef Drissi. A perspective view and survey of meta-learning. Artificial intelligence review, 18:77-95, 2002. +[53] Hao Wang, Hao He, and Dina Katabi. Continuously indexed domain adaptation. In Proceedings of the 37th International Conference on Machine Learning, pages 9898-9907, 2020. +[54] Haoqi Wang, Zhizhong Li, Litong Feng, and Wayne Zhang. Vim: Out-of-distribution with virtual-logit matching. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4921-4930, 2022. +[55] Haotao Wang, Aston Zhang, Yi Zhu, Shuai Zheng, Mu Li, Alex J Smola, and Zhangyang Wang. Partial and asymmetric contrastive learning for out-of-distribution detection in long-tailed recognition. In International Conference on Machine Learning, pages 23446-23458. PMLR, 2022. +[56] Qin Wang, Olga Fink, Luc Van Gool, and Dengxin Dai. Continual test-time domain adaptation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7201-7211, 2022. +[57] Qizhou Wang, Feng Liu, Yonggang Zhang, Jing Zhang, Chen Gong, Tongliang Liu, and Bo Han. Watermarking for out-of-distribution detection. In Advances in Neural Information Processing Systems, 2022. +[58] Qizhou Wang, Junjie Ye, Feng Liu, Quanyu Dai, Marcus Kalander, Tongliang Liu, Jianye Hao, and Bo Han. Out-of-distribution detection with implicit outlier transformation. In International Conference on Learning Representations. OpenReview.net, 2023. +[59] Zitai Wang, Qianqian Xu, Zhiyong Yang, Yuan He, Xiaochun Cao, and Qingming Huang. Openauc: Towards auc-oriented open-set recognition. Advances in Neural Information Processing Systems, 35:25033-25045, 2022. +[60] Hongxin Wei, Renchunzi Xie, Hao Cheng, Lei Feng, Bo An, and Yixuan Li. Mitigating neural network overconfidence with logit normalization. In International Conference on Machine Learning, pages 23631-23644. PMLR, 2022. +[61] Jianxiong Xiao, James Hays, Krista A Ehinger, Aude Oliva, and Antonio Torralba. Sun database: Large-scale scene recognition from abbey to zoo. In 2010 IEEE computer society Conference on Computer Vision and Pattern Recognition, pages 3485-3492. IEEE, 2010. +[62] Jingkang Yang, Haoqi Wang, Litong Feng, Xiaopeng Yan, Huabin Zheng, Wayne Zhang, and Ziwei Liu. Semantically coherent out-of-distribution detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 8301-8309, 2021. +[63] Jingkang Yang, Pengyun Wang, Dejian Zou, Zitang Zhou, Kunyuan Ding, Wenxuan Peng, Haoqi Wang, Guangyao Chen, Bo Li, Yiyou Sun, et al. Openood: Benchmarking generalized out-of-distribution detection. Advances in Neural Information Processing Systems, 35:32598-32611, 2022. + +[64] Jingkang Yang, Kaiyang Zhou, Yixuan Li, and Ziwei Liu. Generalized out-of-distribution detection: A survey. arXiv preprint arXiv:2110.11334, 2021. +[65] Jingkang Yang, Kaiyang Zhou, and Ziwei Liu. Full-spectrum out-of-distribution detection. arXiv preprint arXiv:2204.05306, 2022. +[66] Fisher Yu, Ari Seff, Yinda Zhang, Shuran Song, Thomas Funkhouser, and Jianxiong Xiao. Lsun: Construction of a large-scale image dataset using deep learning with humans in the loop. arXiv preprint arXiv:1506.03365, 2015. +[67] Li Zhong, Zhen Fang, Feng Liu, Bo Yuan, Guangquan Zhang, and Jie Lu. Bridging the theoretical bound and deep algorithms for open set domain adaptation. IEEE Transactions on Neural Networks and Learning Systems, 2021. \ No newline at end of file diff --git a/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/images.zip b/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..eae1d2448c1107fc2ba53c4048cb8cef43dd86cf --- /dev/null +++ b/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:7a4f722cc9fe7158dd7c35e542aa27753ed4ee823c40b54fefbe8ba22d702831 +size 562978 diff --git a/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/layout.json b/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..13db2aacdabef68704cff9584019f7774ae2bf68 --- /dev/null +++ b/2023/Meta OOD Learning For Continuously Adaptive OOD Detection/layout.json @@ -0,0 +1,13802 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 96, + 103, + 498, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 96, + 103, + 498, + 121 + ], + "spans": [ + { + "bbox": [ + 96, + 103, + 498, + 121 + ], + "type": "text", + "content": "Meta OOD Learning For Continuously Adaptive OOD Detection" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 164, + 142, + 430, + 158 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 164, + 142, + 430, + 158 + ], + "spans": [ + { + "bbox": [ + 164, + 142, + 430, + 158 + ], + "type": "text", + "content": "Xinheng Wu† Jie Lu† Zhen Fang† Guangquan Zhang†" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 111, + 158, + 482, + 172 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 158, + 482, + 172 + ], + "spans": [ + { + "bbox": [ + 111, + 158, + 482, + 172 + ], + "type": "text", + "content": "†Australian Artificial Intelligence Institute, University of Technology Sydney" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 83, + 174, + 513, + 186 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 83, + 174, + 513, + 186 + ], + "spans": [ + { + "bbox": [ + 83, + 174, + 513, + 186 + ], + "type": "text", + "content": "Xinheng.Wu@student.uts.edu.au {Jie.Lu, Zhen.Fang, Guangquan.Zhang}@uts.edu.au*" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "spans": [ + { + "bbox": [ + 143, + 213, + 192, + 225 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 238, + 290, + 562 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 238, + 290, + 562 + ], + "spans": [ + { + "bbox": [ + 46, + 238, + 290, + 562 + ], + "type": "text", + "content": "Out-of-distribution (OOD) detection is crucial to modern deep learning applications by identifying and alerting about the OOD samples that should not be tested or used for making predictions. Current OOD detection methods have made significant progress when in-distribution (ID) and OOD samples are drawn from static distributions. However, this can be unrealistic when applied to real-world systems which often undergo continuous variations and shifts in ID and OOD distributions over time. Therefore, for an effective application in real-world systems, the development of OOD detection methods that can adapt to these dynamic and evolving distributions is essential. In this paper, we propose a novel and more realistic setting called continuously adaptive out-of-distribution (CAOD) detection which targets on developing an OOD detection model that enables dynamic and quick adaptation to a new arriving distribution, with insufficient ID samples during deployment time. To address CAOD, we develop meta OOD learning (MOL) by designing a learning-to-adapt diagram such that a good initialized OOD detection model is learned during the training process. In the testing process, MOL ensures OOD detection performance over shifting distributions by quickly adapting to new distributions with a few adaptations. Extensive experiments on several OOD benchmarks endorse the effectiveness of our method in preserving both ID classification accuracy and OOD detection performance on continuously shifting distributions." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 582, + 128, + 596 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 582, + 128, + 596 + ], + "spans": [ + { + "bbox": [ + 47, + 582, + 128, + 596 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 603, + 287, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 603, + 287, + 687 + ], + "spans": [ + { + "bbox": [ + 46, + 603, + 287, + 687 + ], + "type": "text", + "content": "Out-of-distribution (OOD) detection is vital to modern deep learning (DL) applications in the real world, especially in safety-critical applications such as autonomous vehicle control [21], and medical areas [64]. This is because DL systems may make over-confident and incorrect predictions when encountering the out-of-distribution (OOD) samples, which possess semantic labels that are distinct from those" + } + ] + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 308, + 215, + 547, + 365 + ], + "blocks": [ + { + "bbox": [ + 308, + 215, + 547, + 365 + ], + "lines": [ + { + "bbox": [ + 308, + 215, + 547, + 365 + ], + "spans": [ + { + "bbox": [ + 308, + 215, + 547, + 365 + ], + "type": "image", + "image_path": "9074d848afddb7d879dfd4391f528393b7a4670a1fa560a8d108a14404cc2d1c.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 372, + 547, + 420 + ], + "lines": [ + { + "bbox": [ + 305, + 372, + 547, + 420 + ], + "spans": [ + { + "bbox": [ + 305, + 372, + 547, + 420 + ], + "type": "text", + "content": "Figure 1: Difference between existing static OOD detection and a more realistic scenario of Continuously Adaptive OOD Detection (Problem 1) when test samples come from continuously shifting distribution, i.e., Definition 1." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 437, + 547, + 557 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 437, + 547, + 557 + ], + "spans": [ + { + "bbox": [ + 304, + 437, + 547, + 557 + ], + "type": "text", + "content": "of in-distribution (ID) samples [63]. To mitigate this issue, an important problem out-of-distribution detection has been proposed and studied extensively [10, 17]. In OOD detection, the classifier is required to perform accurate predictions on ID samples while simultaneously identifying OOD samples. Many representative methods either utilize outputs [17, 34], feature representations [29, 45], or gradients [19, 32] to enlarge the separations between ID and OOD samples, while others [18, 39] incorporate auxiliary OOD samples to regularize the deep models during training." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 558, + 548, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 548, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 548, + 714 + ], + "type": "text", + "content": "Although OOD detection has achieved great progress, existing methods only focus on a simple scenario where ID and OOD samples are assumed to be drawn from static ID and OOD distributions. However, many real-world systems are changing dynamically and thus inherently exhibit continuous distribution shifts over time. Take a self-driving agent equipped with a scene recognition system as an example: in the real world, the surrounding environment (e.g., illumination, weather) may shift continuously on the road, such as from day to night, and from clean to foggy. Treating the arriving training and test samples as from static distributions may potentially harm the effectiveness of OOD detection, leading to the misclassification of distribution-shifted" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 693, + 287, + 713 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 693, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 693, + 287, + 713 + ], + "type": "text", + "content": "*Corresponding to Jie Lu and Zhen Fang. The work is supported by the Australian Research Council under Discovery Grant DP200100700." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "19353" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 133 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 133 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 133 + ], + "type": "text", + "content": "ID and OOD samples. Such scenarios highlight the limitations of current OOD detection methods when applied to continuously shifting distributions. Figure 1 highlights the difference between OOD detection on static distribution and when applying to continuously shifting distributions." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 134, + 287, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 134, + 287, + 266 + ], + "spans": [ + { + "bbox": [ + 46, + 134, + 287, + 266 + ], + "type": "text", + "content": "To tackle the continuously shifting scenarios in OOD detection, we propose a novel and realistic setting termed continuously adaptive out-of-distribution (CAOOD) detection, which targets on developing OOD detection method to 1) quickly adapt to the continuously shifting ID distributions and 2) detect the continuously shifting OOD samples over time. Note that during the deployment time, the ID samples may be insufficient during the adaptation process. Therefore, how to enable dynamic and quick adaptation with insufficient ID samples to achieve good OOD detection performance over time is core challenge of CAOOD detection." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 267, + 288, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 267, + 288, + 495 + ], + "spans": [ + { + "bbox": [ + 46, + 267, + 288, + 495 + ], + "type": "text", + "content": "Inspired by domain adaptation [14, 6] and meta-learning [13], we develop a novel and effective CAOD detection method called meta out-of-distribution learning (MOL) to address the challenge in CAOD detection. To dynamically and quickly adapt to the continuously shifting ID samples, we leverage the learning-to-learn paradigm [52] of meta-learning which aims to learn an internal representation for quick adaptation to a new task. Specifically, by formulating adaptations to the continuous shifting ID samples as a variety of inner tasks, we design a meta-training procedure for learning to adapt explicitly. Further, to facilitate quick adaptation with insufficient ID samples, we propose to learn a meta-representation during training, which allows us to only update the light-weighted classifier during testing while keeping the meta-representation fixed. Additionally, considering OOD samples are unavailable in training, we propose to generate OOD samples based on the shifting ID feature representations. Lastly, the classifier is trained discriminatively based on both ID and virtual OOD samples." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 59, + 497, + 244, + 508 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 497, + 244, + 508 + ], + "spans": [ + { + "bbox": [ + 59, + 497, + 244, + 508 + ], + "type": "text", + "content": "The contributions are summarized as follows:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 58, + 526, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 7, + "blocks": [ + { + "bbox": [ + 58, + 526, + 287, + 562 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 526, + 287, + 562 + ], + "spans": [ + { + "bbox": [ + 58, + 526, + 287, + 562 + ], + "type": "text", + "content": "- We propose a more realistic OOD detection setting called CAOD detection to promote the applications of OOD detection techniques in real-world scenarios." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 58, + 578, + 287, + 625 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 578, + 287, + 625 + ], + "spans": [ + { + "bbox": [ + 58, + 578, + 287, + 625 + ], + "type": "text", + "content": "- We develop technologies based on meta-learning and domain adaptation to quickly adapt to the continuously shifting ID distributions. With these technologies, MOL is proposed to address CAOD detection." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 58, + 642, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 642, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 58, + 642, + 287, + 713 + ], + "type": "text", + "content": "- We conduct extensive experiments comparing MOL with competitive OOD detection methods using various fine-tuning/adaptation strategies on 114 CAOOD detection tasks. Experiments show that MOL achieves the best performance for both ID classification and OOD detection in continuously shifting distributions." + } + ] + } + ], + "index": 6 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 71, + 392, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 71, + 392, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 71, + 392, + 84 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 91, + 545, + 354 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 91, + 545, + 354 + ], + "spans": [ + { + "bbox": [ + 304, + 91, + 545, + 354 + ], + "type": "text", + "content": "Out-of-distribution Detection methods are mainly post-hoc based adopting different scoring functions based on either logit outputs [17, 32, 34, 46, 28, 20], feature representations [45, 29, 33, 54, 47], or gradients [32, 19, 22]. These methods enjoy good applicability when deployed as they can be easily integrated into a pre-trained model without retraining. Other works utilize contrastive learning [48, 47, 55], specifically designed loss functions [60, 38, 40]. However, these methods often require sophisticated score functions but may not necessarily outperform post-hoc methods in general as noted by [63]. Another line of OOD detection methods focus on regularizing the training of classifier using either auxiliary OOD datasets or generated fake OOD samples [18, 30, 34]. These works study sampling strategies [39, 3, 31], OOD samples generation approaches [30, 51, 8], and uncertainty regularization mechanisms [50]. In addition to above strategies, other strategies have also been explored. For example, to overcome the intrinsic inconsistency of prior metrics by aggregating both the known and unknown class performance in a single performance curve, [59] propose a novel OOD detection metric named OpenAUC as the final objective function to learn OOD detector." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 355, + 545, + 521 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 355, + 545, + 521 + ], + "spans": [ + { + "bbox": [ + 304, + 355, + 545, + 521 + ], + "type": "text", + "content": "Above OOD detection methods neglect inevitable distribution shifts in test data over time in real-world applications. Very few OOD detection works consider such shift: one work [62] used a large unlabeled dataset containing ID samples aiming to encourage ID semantic information modeling while being robust to covariate shift. Another work [65] considers explicitly promotes the generalization capacity of the OOD detector when being evaluated on covariate-shifted ID data. Recent work [41] discovers that environmental-related features (e.g., backgrounds) significantly worsen existing OOD detection performance. These early attempts highlight existing OOD detection methods are prone to distribution shifts and consequently inadequate for realistic scenarios, which motivates our research." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 522, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 522, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 522, + 545, + 713 + ], + "type": "text", + "content": "Domain Adaptation (DA) aims to adapt machine learning models to unseen and different distributions [12, 64, 67, 7]. In complementary to OOD detection, DA improves models' generalization ability to covariate shift when test data share the same label set as training [35, 4]. Most existing DA methods focus on matching discrete source and target domains leveraging domain statistics [42], distance-based loss functions [37], and adversarial training [14]. Recently, different methods are developed to perform continuous domain adaptation when the target domain shifts smoothly over time [2, 53, 56]. Continuous domain adaptation is related to our problem but it does not follow an open-world assumption where test data may contain OOD samples that do not belong to the training label set. In this paper, we address a more challenging open-world learning scenario, OOD detection under continuous shifting distributions." + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19354" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": "Open World Recognition aims to incrementally learn new information without forgetting in an open world [24, 1, 11]. This problem concentrates on zero-shot learning [44], mitigating catastrophic forgetting [25], and incremental learning [43], where unknown samples can be progressively labeled as inputs. This is different from our focus on learning an open-world classifier that can quickly adapt to continuously shifted domains online while maintaining both ID and OOD detection performance. Additional literature on the topic of meta-learning is included in the Appendix." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 205, + 214, + 218 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 205, + 214, + 218 + ], + "spans": [ + { + "bbox": [ + 47, + 205, + 214, + 218 + ], + "type": "text", + "content": "3. Problem Setup and Notations" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "spans": [ + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": "OD Detection. Let " + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "inline_equation", + "content": "\\mathcal{X}" + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": " denote the feature space, " + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "inline_equation", + "content": "\\mathcal{Y} = [C]" + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": " be the label space. We consider the ID distribution " + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "inline_equation", + "content": "D_{X_1Y_1}" + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": " as a joint distribution defined over " + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "inline_equation", + "content": "\\mathcal{X}\\times \\mathcal{Y}" + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "inline_equation", + "content": "X_{\\mathrm{I}}" + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "inline_equation", + "content": "Y_{\\mathrm{I}}" + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": " are random variables whose outputs are from spaces " + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "inline_equation", + "content": "\\mathcal{X}" + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}" + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": ". Given a set of " + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": " samples drawn i.i.d. from the ID distribution called ID data, " + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "inline_equation", + "content": "S = \\{(\\mathbf{x}_j,y_j)\\}_{j = 1}^n\\sim D_{X_1Y_1}" + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": ". A classic classification model " + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "inline_equation", + "content": "\\mathbf{f}:\\mathcal{X}\\to \\mathbb{R}^{C}" + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": ", is trained on the training set " + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 46, + 224, + 287, + 323 + ], + "type": "text", + "content": ", to predict the label of an input test data [10]." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "spans": [ + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "text", + "content": "During the test time of OOD detection, the test samples contain some unknown OOD samples drawn from an OOD distribution " + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "inline_equation", + "content": "D_{X_0Y_0}" + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "inline_equation", + "content": "X_0" + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "text", + "content": " is a random variable from " + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "inline_equation", + "content": "\\mathcal{X}" + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "text", + "content": ", but " + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "inline_equation", + "content": "Y_0" + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "text", + "content": " is a random variable whose outputs do not belong to " + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}" + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "text", + "content": ", i.e., " + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "inline_equation", + "content": "Y_0 \\notin \\mathcal{Y}" + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "text", + "content": ". The classical OOD detection methods aim to design an effective score function " + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "inline_equation", + "content": "s(\\cdot; \\mathbf{f}): \\mathcal{X} \\to \\mathbb{R}" + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "text", + "content": " [32, 29, 34] and train a corresponding model " + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "inline_equation", + "content": "\\mathbf{f}" + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "text", + "content": " by ID samples " + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 46, + 323, + 287, + 418 + ], + "type": "text", + "content": " such that the following OOD detector" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 86, + 430, + 287, + 455 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 86, + 430, + 287, + 455 + ], + "spans": [ + { + "bbox": [ + 86, + 430, + 287, + 455 + ], + "type": "interline_equation", + "content": "G _ {\\gamma} (\\mathbf {x}; s, \\mathbf {f}) = \\left\\{ \\begin{array}{l l} \\text {I D} & \\text {i f} s (\\mathbf {x}; \\mathbf {f}) \\geq \\gamma \\\\ \\text {O O D} & \\text {i f} s (\\mathbf {x}; \\mathbf {f}) < \\gamma \\end{array} \\right. \\tag {1}", + "image_path": "497549746db982652000783949c8a4432bad923d4bb81a188f511691160f1198.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "spans": [ + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "text", + "content": " is a threshold can distinguish ID and OOD samples accurately. In this paper, we select " + }, + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "inline_equation", + "content": "\\gamma" + }, + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "text", + "content": " when " + }, + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "inline_equation", + "content": "95\\%" + }, + { + "bbox": [ + 46, + 462, + 287, + 510 + ], + "type": "text", + "content": " ID data is correctly classified [63, 58, 57], and use energy score [34] as the scoring function to design our OOD detector, i.e.," + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 107, + 521, + 287, + 553 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 107, + 521, + 287, + 553 + ], + "spans": [ + { + "bbox": [ + 107, + 521, + 287, + 553 + ], + "type": "interline_equation", + "content": "s (\\mathbf {x}; \\mathbf {f}) = \\log \\sum_ {l = 1} ^ {C} \\exp (f _ {l} (\\mathbf {x})) \\tag {2}", + "image_path": "d2f372496dd27bfd0427e80ce65e4a3a6f61f1fa9beba0f2fc071ea3762a4ef0.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 560, + 218, + 573 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 560, + 218, + 573 + ], + "spans": [ + { + "bbox": [ + 47, + 560, + 218, + 573 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 560, + 218, + 573 + ], + "type": "inline_equation", + "content": "f_{l}(\\mathbf{x})" + }, + { + "bbox": [ + 47, + 560, + 218, + 573 + ], + "type": "text", + "content": " is the " + }, + { + "bbox": [ + 47, + 560, + 218, + 573 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 47, + 560, + 218, + 573 + ], + "type": "text", + "content": "-th coordinate of " + }, + { + "bbox": [ + 47, + 560, + 218, + 573 + ], + "type": "inline_equation", + "content": "\\mathbf{f}(\\mathbf{x})" + }, + { + "bbox": [ + 47, + 560, + 218, + 573 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "spans": [ + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "text", + "content": "Continuously Adaptive OOD Detection. To tackle more realistic scenarios that the ID and OOD samples are from continuously shifting distributions over a discrete time period " + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "inline_equation", + "content": "T = \\{t_1, t_2, \\dots, t_N\\}" + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "text", + "content": ", which satisfies that " + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "inline_equation", + "content": "0 < t_1 < t_2 < \\dots < t_N" + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "text", + "content": ". We also set " + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "inline_equation", + "content": "T_k = \\{t_1, t_2, \\dots, t_k\\}" + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "text", + "content": " and set " + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "inline_equation", + "content": "T_K^- = \\{t_K, t_{K+1}, \\dots, t_N\\}" + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "inline_equation", + "content": "1 \\leq k < K \\leq N" + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "text", + "content": ". It is clear that " + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "inline_equation", + "content": "T_k \\cup T_K^- \\subset T" + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "inline_equation", + "content": "T_k \\cap T_K^- = \\emptyset" + }, + { + "bbox": [ + 46, + 585, + 287, + 693 + ], + "type": "text", + "content": ". Next, the definition of continuously shifting ID and OOD distributions is given in Definition 1." + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 307, + 72, + 541, + 175 + ], + "blocks": [ + { + "bbox": [ + 307, + 72, + 541, + 175 + ], + "lines": [ + { + "bbox": [ + 307, + 72, + 541, + 175 + ], + "spans": [ + { + "bbox": [ + 307, + 72, + 541, + 175 + ], + "type": "image", + "image_path": "7fe2311f62c252f98969cdc3178bd8fe9b74118ac199578b4527867524a2c396.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 185, + 545, + 237 + ], + "lines": [ + { + "bbox": [ + 305, + 185, + 545, + 237 + ], + "spans": [ + { + "bbox": [ + 305, + 185, + 545, + 237 + ], + "type": "text", + "content": "Figure 2: A heuristic illustration CAOD problem. The target is to train an OOD detection model " + }, + { + "bbox": [ + 305, + 185, + 545, + 237 + ], + "type": "inline_equation", + "content": "g_{0}" + }, + { + "bbox": [ + 305, + 185, + 545, + 237 + ], + "type": "text", + "content": " using S, " + }, + { + "bbox": [ + 305, + 185, + 545, + 237 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t \\in T_k}" + }, + { + "bbox": [ + 305, + 185, + 545, + 237 + ], + "type": "text", + "content": " so it can obtain good OOD detection performance on unseen shifting samples " + }, + { + "bbox": [ + 305, + 185, + 545, + 237 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t \\in T_K^-}" + }, + { + "bbox": [ + 305, + 185, + 545, + 237 + ], + "type": "text", + "content": " by quick adaptation." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "spans": [ + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "text", + "content": "Definition 1 (Continuously Shifting Distributions.) Let " + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "inline_equation", + "content": "D_{X_1Y_1}^t" + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "inline_equation", + "content": "D_{X_0Y_0}^t" + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "text", + "content": " are " + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "inline_equation", + "content": "ID" + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "text", + "content": " and OOD joint distributions at time " + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "inline_equation", + "content": "t \\in T" + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "text", + "content": ". We say " + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "inline_equation", + "content": "D_{X_1Y_1}^t, D_{X_0Y_0}^t" + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "text", + "content": " are continuously shifting " + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "inline_equation", + "content": "ID" + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "text", + "content": " and OOD distributions, if for any " + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "inline_equation", + "content": "i \\in [N-1]" + }, + { + "bbox": [ + 305, + 247, + 545, + 297 + ], + "type": "text", + "content": "," + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 378, + 304, + 472, + 339 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 378, + 304, + 472, + 339 + ], + "spans": [ + { + "bbox": [ + 378, + 304, + 472, + 339 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} d \\left(D _ {X _ {1} Y _ {1}} ^ {t _ {i}}, D _ {X _ {1} Y _ {1}} ^ {t _ {i + 1}}\\right) < \\epsilon , \\\\ d (D _ {X _ {\\mathrm {O}}} ^ {t _ {i}}, D _ {X _ {\\mathrm {O}}} ^ {t _ {i + 1}}) < \\epsilon , \\\\ \\end{array}", + "image_path": "591fff23385247190d41f4ee893d22e20f4f9315ebf4cfcb6bb43ea00235c47a.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 346, + 542, + 358 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 346, + 542, + 358 + ], + "spans": [ + { + "bbox": [ + 306, + 346, + 542, + 358 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 306, + 346, + 542, + 358 + ], + "type": "inline_equation", + "content": "d(\\cdot, \\cdot)" + }, + { + "bbox": [ + 306, + 346, + 542, + 358 + ], + "type": "text", + "content": " is a distribution metric and " + }, + { + "bbox": [ + 306, + 346, + 542, + 358 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 306, + 346, + 542, + 358 + ], + "type": "text", + "content": " is a small value." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 368, + 545, + 440 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 368, + 545, + 440 + ], + "spans": [ + { + "bbox": [ + 305, + 368, + 545, + 440 + ], + "type": "text", + "content": "In Definition 1, the small value " + }, + { + "bbox": [ + 305, + 368, + 545, + 440 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 305, + 368, + 545, + 440 + ], + "type": "text", + "content": " is used to estimate the gradual variations and quantify the continuity of continuously shifting ID and OOD distributions. We note here that distribution shift over time can be significant as it gradually accumulates. Next, we give the definition of continuously adaptive OOD detection." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 449, + 531, + 461 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 449, + 531, + 461 + ], + "spans": [ + { + "bbox": [ + 305, + 449, + 531, + 461 + ], + "type": "text", + "content": "Problem 1 (Continuously Adaptive OOD Detection.)" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 305, + 461, + 545, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 461, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 305, + 461, + 545, + 498 + ], + "type": "text", + "content": "Let " + }, + { + "bbox": [ + 305, + 461, + 545, + 498 + ], + "type": "inline_equation", + "content": "D_{X_{\\mathrm{I}}Y_{\\mathrm{I}}}^{t}" + }, + { + "bbox": [ + 305, + 461, + 545, + 498 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 461, + 545, + 498 + ], + "type": "inline_equation", + "content": "D_{X_{\\mathrm{O}}Y_{\\mathrm{O}}}^{t}" + }, + { + "bbox": [ + 305, + 461, + 545, + 498 + ], + "type": "text", + "content": " be the continuously shifting ID and OOD distributions over time period " + }, + { + "bbox": [ + 305, + 461, + 545, + 498 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 305, + 461, + 545, + 498 + ], + "type": "text", + "content": " and let " + }, + { + "bbox": [ + 305, + 461, + 545, + 498 + ], + "type": "inline_equation", + "content": "D_{X_{\\mathrm{I}}Y_{\\mathrm{I}}}" + }, + { + "bbox": [ + 305, + 461, + 545, + 498 + ], + "type": "text", + "content": " be the original ID distribution. Given sets of samples" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 343, + 506, + 528, + 520 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 343, + 506, + 528, + 520 + ], + "spans": [ + { + "bbox": [ + 343, + 506, + 528, + 520 + ], + "type": "interline_equation", + "content": "S = \\left\\{\\left(\\mathbf {x} _ {1}, y _ {1}\\right), \\dots , \\left(\\mathbf {x} _ {n}, y _ {n}\\right) \\right\\} \\sim D _ {X _ {1} Y _ {1}}, i. i. d.", + "image_path": "ef01bf9aa006eb1ea25167d73822f1c054bdaa1ee5f956787942a63f83e92e4e.jpg" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 323, + 521, + 529, + 536 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 323, + 521, + 529, + 536 + ], + "spans": [ + { + "bbox": [ + 323, + 521, + 529, + 536 + ], + "type": "interline_equation", + "content": "S ^ {t} = \\left\\{\\mathbf {x} _ {1} ^ {t}, \\dots , \\mathbf {x} _ {n} ^ {t} \\right\\} \\sim D _ {X _ {1}} ^ {t}, i. i. d., f o r e a c h t \\in T", + "image_path": "570d114b2146aae5e17e7df3559a3e4e35f529d2a7e983abadbe7152d978a029.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "spans": [ + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": "with " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "n^t \\ll n" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": " if " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "t \\in T_K^-" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": ", the aim of continuously adaptive OOD detection is to train an initial OOD detection model " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "g_0" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": " using " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t \\in T_k}" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": ", and to quickly update the model " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "g_{t_i}" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": " (at each time " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "t_i \\in T_K^- = \\{t_K, t_{K+1}, \\dots, t_N\\}" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": ") based on the previous model " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "g_{t_{i-1}}" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": " (" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "g_0" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": " is the initial model, i.e., " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "g_{t_{K-1}} = g_0" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": ") using " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "S^{t_i}" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": ". Such that for any test sample " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "\\mathbf{x} \\in \\{S^t\\}_{t \\in T_K^-}" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": ": 1) if " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": " is from ID distribution " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "D_{X_1}^t" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "g_{t_N}" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": " classifies " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": " into correct ID label; and 2) if " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": " is from OOD distribution " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "D_{X_0}^t" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "g_{t_N}" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": " detects " + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 305, + 545, + 545, + 657 + ], + "type": "text", + "content": " as OOD." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 305, + 665, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 665, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 305, + 665, + 545, + 714 + ], + "type": "text", + "content": "A heuristic illustration of the CAOD problem is provided in Figure 2. The key challenge of Problem 1 is to quickly adapt to new ID distribution " + }, + { + "bbox": [ + 305, + 665, + 545, + 714 + ], + "type": "inline_equation", + "content": "D_{X_1}^{t_i}" + }, + { + "bbox": [ + 305, + 665, + 545, + 714 + ], + "type": "text", + "content": " using insufficient ID samples " + }, + { + "bbox": [ + 305, + 665, + 545, + 714 + ], + "type": "inline_equation", + "content": "S^{t_i}" + }, + { + "bbox": [ + 305, + 665, + 545, + 714 + ], + "type": "text", + "content": " at time " + }, + { + "bbox": [ + 305, + 665, + 545, + 714 + ], + "type": "inline_equation", + "content": "t_i" + }, + { + "bbox": [ + 305, + 665, + 545, + 714 + ], + "type": "text", + "content": ". To achieve satisfied performance" + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 58, + 702, + 286, + 714 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 286, + 714 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 286, + 714 + ], + "type": "text", + "content": "1We use [N] to represent set {1,..., N}. Therefore, " + }, + { + "bbox": [ + 58, + 702, + 286, + 714 + ], + "type": "inline_equation", + "content": "[C] = \\{1,\\dots,C\\}" + }, + { + "bbox": [ + 58, + 702, + 286, + 714 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19355" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": "across time period " + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "T_{K}^{-}" + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": ", a good initial OOD detection model " + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "g_{0}" + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": " is indispensable for effective adaptation. In Section 4, we illustrate the proposed MOL method and detail how to obtain the initial model " + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "inline_equation", + "content": "g_{0}" + }, + { + "bbox": [ + 46, + 72, + 287, + 120 + ], + "type": "text", + "content": " during the training procedure." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "spans": [ + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": "Notations. To facilitate better comprehension, we introduce some necessary notations. To learn a good initial OOD detection model " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "g_{0}" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": ", we mainly use meta-learning techniques. Following the meta-training procedure [13], we need to sample a support set " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "\\mathbf{S}_{\\mathrm{spt}} = \\{S_{\\mathrm{spt}}^{t}\\}_{t\\in T_{k}^{\\prime}}" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t\\in T_k}" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "T_{k}^{\\prime}\\subset T_{k}" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "S_{\\mathrm{spt}}^{t}\\subset S^{t}" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": ". We also need to sample a query set " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "\\mathbf{S}_{\\mathrm{qry}} = \\{S_{\\mathrm{qry}}^{t}\\}_{t\\in T_{k}^{\\prime}}" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t\\in T_k}" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "S_{\\mathrm{qry}}^{t}\\subset S^{t}" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": ". Further, we set " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_{\\Theta}" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": " to be the feature extractor, set " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "\\mathbf{h}_{\\Phi}" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": " to be the adapter, and set " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "\\mathbf{c}_W" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": " to be the classifier, where " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "\\Theta ,\\Phi" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "W" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": " are the parameters. Then the classification model " + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "inline_equation", + "content": "\\mathbf{f}" + }, + { + "bbox": [ + 46, + 121, + 288, + 255 + ], + "type": "text", + "content": " can be expressed as a function composition:" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 115, + 262, + 218, + 275 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 115, + 262, + 218, + 275 + ], + "spans": [ + { + "bbox": [ + 115, + 262, + 218, + 275 + ], + "type": "interline_equation", + "content": "\\mathbf {f} _ {W, \\Phi , \\Theta} = \\mathbf {c} _ {W} \\circ \\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta}.", + "image_path": "9a0dcde84515b11ae74998bffec5b34e1669f6618c18e048f9e460a38f82ae56.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 283, + 287, + 308 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 283, + 287, + 308 + ], + "spans": [ + { + "bbox": [ + 46, + 283, + 287, + 308 + ], + "type": "text", + "content": "Lastly, the OOD detection model " + }, + { + "bbox": [ + 46, + 283, + 287, + 308 + ], + "type": "inline_equation", + "content": "G_{\\gamma}" + }, + { + "bbox": [ + 46, + 283, + 287, + 308 + ], + "type": "text", + "content": " can be obtained via the score function " + }, + { + "bbox": [ + 46, + 283, + 287, + 308 + ], + "type": "inline_equation", + "content": "s(\\cdot ;\\mathbf{f}_{W,\\Phi ,\\Theta})" + }, + { + "bbox": [ + 46, + 283, + 287, + 308 + ], + "type": "text", + "content": " as shown in Eqs. 1 and 2." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 308, + 287, + 345 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 308, + 287, + 345 + ], + "spans": [ + { + "bbox": [ + 46, + 308, + 287, + 345 + ], + "type": "text", + "content": "To adapt the shifting distributions, we mainly utilize the maximum mean discrepancy (MMD) [15], which are introduced in following: given samples " + }, + { + "bbox": [ + 46, + 308, + 287, + 345 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{x}_i\\}_{i=1}^n" + }, + { + "bbox": [ + 46, + 308, + 287, + 345 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 308, + 287, + 345 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{x}_j'\\}_{j=1}^m" + }, + { + "bbox": [ + 46, + 308, + 287, + 345 + ], + "type": "text", + "content": "," + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 91, + 354, + 243, + 400 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 354, + 243, + 400 + ], + "spans": [ + { + "bbox": [ + 91, + 354, + 243, + 400 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} d _ {k} (\\{\\mathbf {x} _ {i} \\} _ {i = 1} ^ {n}, \\{\\mathbf {x} _ {j} ^ {\\prime} \\} _ {j = 1} ^ {m}) \\\\ = \\left\\| \\frac {1}{n} \\sum_ {i = 1} ^ {n} \\phi_ {k} (\\mathbf {x} _ {i}) - \\frac {1}{m} \\sum_ {i = 1} ^ {m} \\phi_ {k} (\\mathbf {x} _ {j}) \\right\\| _ {k}, \\\\ \\end{array}", + "image_path": "1b032fcec87178ce40675fa50c48c0b11889dcc330c35439b2b70600804c06c9.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 407, + 287, + 443 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 407, + 287, + 443 + ], + "spans": [ + { + "bbox": [ + 46, + 407, + 287, + 443 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 407, + 287, + 443 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 46, + 407, + 287, + 443 + ], + "type": "text", + "content": " is the kernel and " + }, + { + "bbox": [ + 46, + 407, + 287, + 443 + ], + "type": "inline_equation", + "content": "\\phi_{k}" + }, + { + "bbox": [ + 46, + 407, + 287, + 443 + ], + "type": "text", + "content": " is the kernel feature map. To further improve the adaptive performance, in this work, we use the multi-kernel MMD " + }, + { + "bbox": [ + 46, + 407, + 287, + 443 + ], + "type": "inline_equation", + "content": "d_{mk}" + }, + { + "bbox": [ + 46, + 407, + 287, + 443 + ], + "type": "text", + "content": ", which is shown in [36]." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 454, + 129, + 467 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 454, + 129, + 467 + ], + "spans": [ + { + "bbox": [ + 47, + 454, + 129, + 467 + ], + "type": "text", + "content": "4. Methodology" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "spans": [ + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "text", + "content": "It is important to recognize that while the number of test samples " + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "inline_equation", + "content": "S^t (t \\in T_K^-)" + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "text", + "content": " may be limited during deployment, we often have access to a satisfactory number of labeled training samples " + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "text", + "content": " as well as unlabeled samples " + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t \\in T_k}" + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "text", + "content": " that can be used to simulate distribution shifts that may occur during deployment. This motivates us to learn a well-designed initial OOD detection model " + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "inline_equation", + "content": "g_0" + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "text", + "content": " that utilizes both labeled training samples " + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "text", + "content": " and unlabeled samples " + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t \\in T_k}" + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "text", + "content": " to effectively adapt to the shifting test samples " + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "inline_equation", + "content": "S^t (t \\in T_K^-)" + }, + { + "bbox": [ + 46, + 474, + 287, + 592 + ], + "type": "text", + "content": " as defined in Problem 1." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 594, + 287, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 287, + 712 + ], + "type": "text", + "content": "To develop an effective initial OOD detection model " + }, + { + "bbox": [ + 46, + 594, + 287, + 712 + ], + "type": "inline_equation", + "content": "g_0" + }, + { + "bbox": [ + 46, + 594, + 287, + 712 + ], + "type": "text", + "content": ", we consider learning an internal meta-representation that enables efficient adaptation to the new distributions in Problem 1. Additionally, note that OOD samples are unavailable during the training process, we utilize the virtual OOD synthesize [8] techniques to generate reliable-virtual OOD samples. The virtual OOD samples emulate real OOD samples and thus enable the classifier to be trained with an additional uncertainty regularization term that incorporates both ID and virtual OOD information." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 72, + 545, + 288 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 288 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 288 + ], + "type": "text", + "content": "An effective strategy of learning " + }, + { + "bbox": [ + 304, + 72, + 545, + 288 + ], + "type": "inline_equation", + "content": "g_{0}" + }, + { + "bbox": [ + 304, + 72, + 545, + 288 + ], + "type": "text", + "content": " is to draw upon the experience of meta-learning [9, 52]. Originally proposed for addressing few-shot learning [9, 23], meta-learning involves utilizing fast adaptation on a small number of samples. By using meta-learning [13], we can efficiently adapt the initial model to new distributions encountered during deployment. Specifically, a meta-training process is explicitly designed for learning-to-adapt by viewing the adaptation to each time " + }, + { + "bbox": [ + 304, + 72, + 545, + 288 + ], + "type": "inline_equation", + "content": "t \\in T_k'" + }, + { + "bbox": [ + 304, + 72, + 545, + 288 + ], + "type": "text", + "content": " for OOD detection as the inner tasks, thus dynamic adaptations across all time periods " + }, + { + "bbox": [ + 304, + 72, + 545, + 288 + ], + "type": "inline_equation", + "content": "T_k'" + }, + { + "bbox": [ + 304, + 72, + 545, + 288 + ], + "type": "text", + "content": " can be regarded as one input for the outer-loop training process. Concretely, we can train the classifier by considering both ID adaptation and OOD uncertainty regularization. In the outer loop, we update the model with respect to many inner tasks across all time periods " + }, + { + "bbox": [ + 304, + 72, + 545, + 288 + ], + "type": "inline_equation", + "content": "T_k'" + }, + { + "bbox": [ + 304, + 72, + 545, + 288 + ], + "type": "text", + "content": ". We detail the inner learning tasks and outer-loop meta-training process in Sections 4.1 and 4.2. The entire procedures of the proposed MOL method are shown in Algorithms 1 and 2." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 297, + 471, + 309 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 297, + 471, + 309 + ], + "spans": [ + { + "bbox": [ + 305, + 297, + 471, + 309 + ], + "type": "text", + "content": "4.1. Inner Learning Task for MOL" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "spans": [ + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "text", + "content": "ID Adaptation. In the inner task, we firstly train the adapter " + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "inline_equation", + "content": "\\mathbf{h}_{\\Phi}" + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "text", + "content": " and classifier " + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "inline_equation", + "content": "\\mathbf{c}_W" + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "text", + "content": " to adapt to current ID distribution at time point " + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "inline_equation", + "content": "t \\in T_k'" + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "text", + "content": " using support set " + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "inline_equation", + "content": "\\mathbf{S}_{\\mathrm{spt}}" + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "text", + "content": ". Specifically, given a cross-entropy loss " + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "inline_equation", + "content": "\\ell_{\\mathrm{ce}}" + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "text", + "content": " and multi-kernel MMD " + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "inline_equation", + "content": "d_{mk}" + }, + { + "bbox": [ + 304, + 316, + 545, + 376 + ], + "type": "text", + "content": ", we minimize the following objective." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 312, + 387, + 545, + 436 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 387, + 545, + 436 + ], + "spans": [ + { + "bbox": [ + 312, + 387, + 545, + 436 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\min _ {\\Phi , W} \\left[ \\mathcal {L} _ {\\mathrm {c e}} + \\mathcal {L} _ {\\mathrm {d}} ^ {t} \\right] = \\min _ {\\Phi , W} \\left[ \\frac {1}{n} \\sum_ {i = 1} ^ {n} \\ell_ {\\mathrm {c e}} \\left(\\mathbf {f} _ {\\Theta , \\Phi , W} \\left(\\mathbf {x} _ {i}\\right), y _ {i}\\right) \\right. \\tag {3} \\\\ \\left. \\right. + d _ {m k} ^ {2} \\big (\\{\\mathbf {f} _ {\\Theta , \\Phi , W} (\\mathbf {x} _ {i}) \\} _ {i = 1} ^ {n}, \\{\\mathbf {f} _ {\\Theta , \\Phi , W} (\\mathbf {x} _ {j, \\mathrm {s p t}} ^ {t}) \\} _ {j = 1} ^ {m ^ {t}} \\big) \\big ], \\\\ \\end{array}", + "image_path": "ad642e8a951ff3eadbcd3bf9028b31580745f9e37e301b7c8720a662c4a3dffe.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "spans": [ + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{x}_{j,\\mathrm{spt}}^t\\}_{j = 1}^m = S_{\\mathrm{spt}}^t" + }, + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "type": "text", + "content": " . Then at each time " + }, + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "type": "inline_equation", + "content": "t\\in T_k^\\prime" + }, + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "type": "text", + "content": " , we estimate the empirical mean and covariance of training samples " + }, + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "type": "text", + "content": " for each class " + }, + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "type": "inline_equation", + "content": "c\\in \\mathcal{V}" + }, + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "type": "text", + "content": " using " + }, + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "type": "inline_equation", + "content": "\\mathbf{h}_{\\Phi}\\circ \\mathbf{f}_{\\Theta}" + }, + { + "bbox": [ + 304, + 447, + 545, + 484 + ], + "type": "text", + "content": " [29]," + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 321, + 494, + 545, + 528 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 321, + 494, + 545, + 528 + ], + "spans": [ + { + "bbox": [ + 321, + 494, + 545, + 528 + ], + "type": "interline_equation", + "content": "\\hat {\\boldsymbol {\\mu}} _ {c} ^ {t} = \\frac {1}{n _ {c}} \\sum_ {i: y _ {i} = c} \\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta} \\left(\\mathbf {x} _ {i}\\right), \\quad \\hat {\\boldsymbol {\\Sigma}} ^ {t} = \\frac {1}{n} \\sum_ {c = 1} ^ {C} \\hat {\\boldsymbol {\\Sigma}} _ {c} ^ {t}, \\tag {4}", + "image_path": "f4b82a6fae8634f806cbd3e824c411bedc581b0ac58eced81054268ae33d340a.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 538, + 520, + 550 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 538, + 520, + 550 + ], + "spans": [ + { + "bbox": [ + 306, + 538, + 520, + 550 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 306, + 538, + 520, + 550 + ], + "type": "inline_equation", + "content": "n_c" + }, + { + "bbox": [ + 306, + 538, + 520, + 550 + ], + "type": "text", + "content": " is the number of samples " + }, + { + "bbox": [ + 306, + 538, + 520, + 550 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 306, + 538, + 520, + 550 + ], + "type": "text", + "content": " for class " + }, + { + "bbox": [ + 306, + 538, + 520, + 550 + ], + "type": "inline_equation", + "content": "c" + }, + { + "bbox": [ + 306, + 538, + 520, + 550 + ], + "type": "text", + "content": ", and" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 560, + 537, + 592 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 560, + 537, + 592 + ], + "spans": [ + { + "bbox": [ + 306, + 560, + 537, + 592 + ], + "type": "interline_equation", + "content": "\\hat {\\boldsymbol {\\Sigma}} _ {c} ^ {t} = \\sum_ {i: y _ {i} = c} ^ {n} \\left(\\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta} \\left(\\mathbf {x} _ {i}\\right) - \\hat {\\boldsymbol {\\mu}} _ {c} ^ {t}\\right) \\left(\\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta} \\left(\\mathbf {x} _ {i}\\right) - \\hat {\\boldsymbol {\\mu}} _ {c} ^ {t}\\right) ^ {\\top}.", + "image_path": "20d9be3d94abd1fe2691bc62a8eb55e67fe51097d76667fd6df5441cab51c0cc.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 602, + 545, + 626 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 602, + 545, + 626 + ], + "spans": [ + { + "bbox": [ + 304, + 602, + 545, + 626 + ], + "type": "text", + "content": "Note that the adapter " + }, + { + "bbox": [ + 304, + 602, + 545, + 626 + ], + "type": "inline_equation", + "content": "\\mathbf{h}_{\\Phi}" + }, + { + "bbox": [ + 304, + 602, + 545, + 626 + ], + "type": "text", + "content": " is updated by the training objective in Eq. (3) at each time " + }, + { + "bbox": [ + 304, + 602, + 545, + 626 + ], + "type": "inline_equation", + "content": "t\\in T_k^{\\prime}" + }, + { + "bbox": [ + 304, + 602, + 545, + 626 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 627, + 545, + 686 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 627, + 545, + 686 + ], + "spans": [ + { + "bbox": [ + 304, + 627, + 545, + 686 + ], + "type": "text", + "content": "Virtual OOD Generation. We generate virtual OOD samples based on the updated ID features " + }, + { + "bbox": [ + 304, + 627, + 545, + 686 + ], + "type": "inline_equation", + "content": "\\mathbf{h}_{\\Phi} \\circ \\mathbf{f}_{\\Theta}" + }, + { + "bbox": [ + 304, + 627, + 545, + 686 + ], + "type": "text", + "content": " at each time " + }, + { + "bbox": [ + 304, + 627, + 545, + 686 + ], + "type": "inline_equation", + "content": "t \\in T_k'" + }, + { + "bbox": [ + 304, + 627, + 545, + 686 + ], + "type": "text", + "content": ". Motivated by [8, 29], we also assume that adapted class-conditional ID distribution " + }, + { + "bbox": [ + 304, + 627, + 545, + 686 + ], + "type": "inline_equation", + "content": "D_{\\mathbf{h}_{\\Phi} \\circ \\mathbf{f}_{\\Theta}(X_{\\mathrm{I}}) | Y_{\\mathrm{I}} = c}^{t}" + }, + { + "bbox": [ + 304, + 627, + 545, + 686 + ], + "type": "text", + "content": " is similar to a multivariate Gaussian distribution, i.e.," + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 357, + 696, + 494, + 716 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 357, + 696, + 494, + 716 + ], + "spans": [ + { + "bbox": [ + 357, + 696, + 494, + 716 + ], + "type": "interline_equation", + "content": "D _ {\\mathbf {h} _ {\\Phi} \\circ \\mathbf {f} _ {\\Theta} (X _ {\\mathrm {I}}) | Y _ {\\mathrm {I}} = c} ^ {t} \\approx \\mathcal {N} \\left(\\hat {\\mu} _ {c} ^ {t}, \\hat {\\Sigma} ^ {t}\\right),", + "image_path": "242ced82d70c57eb1892b6cfb40cbe99a2ef9eb2122073549ec5d3222d2b26c7.jpg" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19356" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "type": "text", + "content": "which implies that we can sample virtual OOD samples " + }, + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "type": "inline_equation", + "content": "Z_{c}^{t}" + }, + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "type": "text", + "content": " at the adapted feature space " + }, + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "type": "inline_equation", + "content": "\\mathcal{Z} = \\mathbf{h}_{\\Phi}\\circ \\mathbf{f}_{\\Theta}(\\mathcal{X})\\subset \\mathbb{R}^{\\tilde{d}}" + }, + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "type": "text", + "content": " to each class " + }, + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "type": "inline_equation", + "content": "c" + }, + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "type": "text", + "content": " in the " + }, + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "type": "inline_equation", + "content": "\\delta" + }, + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "type": "text", + "content": "-likelihood region, i.e., " + }, + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "type": "inline_equation", + "content": "Z_{c}^{t}" + }, + { + "bbox": [ + 47, + 72, + 287, + 111 + ], + "type": "text", + "content": " is sampled from" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 56, + 116, + 287, + 143 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 116, + 287, + 143 + ], + "spans": [ + { + "bbox": [ + 56, + 116, + 287, + 143 + ], + "type": "interline_equation", + "content": "\\left\\{\\mathbf {z} _ {c} ^ {t} \\mid \\frac {A}{| \\hat {\\boldsymbol {\\Sigma}} | ^ {1 / 2}} \\exp \\left(\\left(\\mathbf {z} _ {c} ^ {t} - \\hat {\\boldsymbol {\\mu}} _ {c} ^ {t}\\right) \\hat {\\boldsymbol {\\Sigma}} ^ {- 1} \\left(\\mathbf {z} _ {c} ^ {t} - \\hat {\\boldsymbol {\\mu}} _ {c} ^ {t}\\right)\\right) < \\delta \\right\\}, \\tag {5}", + "image_path": "caeae81d685184d331edcb0b5ac69f97983d16a5d472b5424f317bd39594a029.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 151, + 287, + 189 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 151, + 287, + 189 + ], + "spans": [ + { + "bbox": [ + 47, + 151, + 287, + 189 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 151, + 287, + 189 + ], + "type": "inline_equation", + "content": "A = 1 / (2\\pi)^{\\tilde{d} /2}" + }, + { + "bbox": [ + 47, + 151, + 287, + 189 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 151, + 287, + 189 + ], + "type": "inline_equation", + "content": "\\delta" + }, + { + "bbox": [ + 47, + 151, + 287, + 189 + ], + "type": "text", + "content": " is a small constant to ensure that the sampled OOD samples " + }, + { + "bbox": [ + 47, + 151, + 287, + 189 + ], + "type": "inline_equation", + "content": "Z_{c}^{t}" + }, + { + "bbox": [ + 47, + 151, + 287, + 189 + ], + "type": "text", + "content": " are near the estimated class boundary in the adapted feature space " + }, + { + "bbox": [ + 47, + 151, + 287, + 189 + ], + "type": "inline_equation", + "content": "\\mathcal{Z}" + }, + { + "bbox": [ + 47, + 151, + 287, + 189 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 190, + 287, + 274 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 190, + 287, + 274 + ], + "spans": [ + { + "bbox": [ + 46, + 190, + 287, + 274 + ], + "type": "text", + "content": "Inner Uncertainty Regularization. By the above steps, at each time " + }, + { + "bbox": [ + 46, + 190, + 287, + 274 + ], + "type": "inline_equation", + "content": "t \\in T_k'" + }, + { + "bbox": [ + 46, + 190, + 287, + 274 + ], + "type": "text", + "content": ", we obtained the adapting ID information and the virtual OOD samples at the adapted feature space " + }, + { + "bbox": [ + 46, + 190, + 287, + 274 + ], + "type": "inline_equation", + "content": "\\mathcal{Z}" + }, + { + "bbox": [ + 46, + 190, + 287, + 274 + ], + "type": "text", + "content": ". Now we add an extra regularization term such that the classifier " + }, + { + "bbox": [ + 46, + 190, + 287, + 274 + ], + "type": "inline_equation", + "content": "\\mathbf{c}_W" + }, + { + "bbox": [ + 46, + 190, + 287, + 274 + ], + "type": "text", + "content": " can classify the adapted ID samples and virtual OOD samples in the adapted feature space " + }, + { + "bbox": [ + 46, + 190, + 287, + 274 + ], + "type": "inline_equation", + "content": "\\mathcal{Z}" + }, + { + "bbox": [ + 46, + 190, + 287, + 274 + ], + "type": "text", + "content": ". Specifically, the regularization term [8] is shown in following," + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 70, + 280, + 287, + 342 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 280, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 70, + 280, + 287, + 342 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {L} _ {\\mathrm {o o d}} ^ {t} = \\frac {1}{C} \\sum_ {c = 1} ^ {C} \\mathbb {E} _ {\\mathbf {z} \\sim \\mathcal {Z} _ {c} ^ {t}} \\left[ - \\log \\frac {1}{1 + \\exp^ {s (\\mathbf {z} ; \\mathbf {c} _ {W})}} \\right] \\tag {6} \\\\ + \\mathbb {E} _ {\\mathbf {x} \\sim S _ {\\mathrm {s p t}} ^ {t}} \\left[ - \\log \\frac {\\exp^ {s (\\mathbf {x} ; \\mathbf {f} _ {W , \\Phi , \\Theta})}}{1 + \\exp^ {s (\\mathbf {x} ; \\mathbf {f} _ {W , \\Phi , \\Theta})}} \\right], \\\\ \\end{array}", + "image_path": "1f9e8ef84ca09e663d68be66b7c91bfcfff76f74e1ea785392df0b11a3ccb874.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 347, + 287, + 383 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 347, + 287, + 383 + ], + "spans": [ + { + "bbox": [ + 47, + 347, + 287, + 383 + ], + "type": "text", + "content": "where the score function " + }, + { + "bbox": [ + 47, + 347, + 287, + 383 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 47, + 347, + 287, + 383 + ], + "type": "text", + "content": " is introduced in Eq. (2). Therefore, we obtain the optimization problem for inner tasks by combining Eq. (3) and (6), i.e., for a parameter " + }, + { + "bbox": [ + 47, + 347, + 287, + 383 + ], + "type": "inline_equation", + "content": "\\lambda > 0" + }, + { + "bbox": [ + 47, + 347, + 287, + 383 + ], + "type": "text", + "content": "," + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 91, + 388, + 287, + 407 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 388, + 287, + 407 + ], + "spans": [ + { + "bbox": [ + 91, + 388, + 287, + 407 + ], + "type": "interline_equation", + "content": "\\min _ {W, \\Phi} \\mathcal {L} ^ {t} = \\min _ {W, \\Phi} \\left[ \\mathcal {L} _ {\\mathrm {c e}} + \\mathcal {L} _ {\\mathrm {d}} ^ {t} + \\lambda \\mathcal {L} _ {\\mathrm {o o d}} ^ {t} \\right]. \\tag {7}", + "image_path": "35254a148fc5cf59019cbe8a973ee29bb8c4d720afda1d6d84163cfc72ec529b.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "spans": [ + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "text", + "content": "Note that at the earlier training stage, we optimize " + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "inline_equation", + "content": "\\Phi" + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "inline_equation", + "content": "W" + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "text", + "content": " only by using Eq. (3) so that a good estimation of ID distribution can be learned. Specifically, following VOS [8], we maintained a ID class-conditional queue " + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "inline_equation", + "content": "|Q_y|" + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "text", + "content": " for each class " + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "inline_equation", + "content": "y \\in \\mathcal{V}" + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "text", + "content": " for continuous online estimation of " + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "inline_equation", + "content": "\\hat{\\mu}_c^t" + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "inline_equation", + "content": "\\hat{\\Sigma}^t" + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "text", + "content": ". The uncertainty regularization (Eq. (7)) is introduced in the middle of the training (i.e., at a certain starting epoch " + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "inline_equation", + "content": "E" + }, + { + "bbox": [ + 47, + 414, + 287, + 499 + ], + "type": "text", + "content": ")." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 506, + 222, + 519 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 506, + 222, + 519 + ], + "spans": [ + { + "bbox": [ + 47, + 506, + 222, + 519 + ], + "type": "text", + "content": "4.2. Learning A Meta-representation" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "spans": [ + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "content": "Outer-loop Training. In Section 4.1, the inner training task only involves updating the adapter " + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "inline_equation", + "content": "\\mathbf{h}_{\\Phi}" + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "content": " and classifier " + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "inline_equation", + "content": "\\mathbf{c}_W" + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "content": " while keeping the feature extractor " + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_{\\Theta}" + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "content": " fixed. In the outer loop, we target on updating " + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_{\\Theta}" + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "content": " corresponding to fixed " + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "inline_equation", + "content": "\\Phi" + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "inline_equation", + "content": "W" + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "content": " given in the inner tasks at each time " + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "inline_equation", + "content": "t \\in T_k'" + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "content": ". Firstly, considering harnessing the knowledge transfer between continuous shifting distributions during time period " + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "inline_equation", + "content": "T_k'" + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "content": ", we minimize the distribution discrepancy across the time period " + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "inline_equation", + "content": "T_k'" + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "content": ": let " + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "inline_equation", + "content": "T_k' = \\{t_1', t_2', \\dots, t_l'\\}" + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "inline_equation", + "content": "t_1' < t_2' < \\dots < t_l'" + }, + { + "bbox": [ + 47, + 524, + 287, + 633 + ], + "type": "text", + "content": ", then" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 56, + 639, + 287, + 663 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 639, + 287, + 663 + ], + "spans": [ + { + "bbox": [ + 56, + 639, + 287, + 663 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {q r y}} = \\max _ {i \\in [ l - 1 ]} d _ {m k} ^ {2} \\left(\\mathbf {f} _ {\\Theta , \\Phi , W} \\left(S _ {\\mathrm {q r y}} ^ {t _ {i + 1} ^ {\\prime}}\\right), \\mathbf {f} _ {\\Theta , \\Phi , W} \\left(S _ {\\mathrm {q r y}} ^ {t _ {i} ^ {\\prime}}\\right)\\right), \\tag {8}", + "image_path": "152db9e018969cd69aeed23adfb55272dccb981d452a4cae49eebbcc53918baa.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 670, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 670, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 47, + 670, + 287, + 714 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 670, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_{\\Theta ,\\Phi ,W}(S_{\\mathrm{qry}}^{t_i'}) = \\{\\mathbf{f}_{\\Theta ,\\Phi ,W}(\\mathbf{x}_{j,\\mathrm{qry}}^{t_i'})\\}_{j = 1}^{m't_i'}" + }, + { + "bbox": [ + 47, + 670, + 287, + 714 + ], + "type": "text", + "content": " here we set " + }, + { + "bbox": [ + 47, + 670, + 287, + 714 + ], + "type": "inline_equation", + "content": "S_{\\mathrm{qry}}^{t_i'} = \\{\\mathbf{x}_{j,\\mathrm{qry}}^{t_i'}\\}_{j = 1}^{m't_i}" + }, + { + "bbox": [ + 47, + 670, + 287, + 714 + ], + "type": "text", + "content": ". Intuitively, " + }, + { + "bbox": [ + 47, + 670, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{qry}}" + }, + { + "bbox": [ + 47, + 670, + 287, + 714 + ], + "type": "text", + "content": " estimates the discrepancies of continuously shifting distributions across the" + } + ] + } + ], + "index": 11 + }, + { + "type": "code", + "bbox": [ + 306, + 87, + 545, + 276 + ], + "blocks": [ + { + "bbox": [ + 307, + 72, + 471, + 84 + ], + "lines": [ + { + "bbox": [ + 307, + 72, + 471, + 84 + ], + "spans": [ + { + "bbox": [ + 307, + 72, + 471, + 84 + ], + "type": "text", + "content": "Algorithm 1. MOL in Training Process" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "code_caption" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "lines": [ + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "spans": [ + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": "Input: ID training samples " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t\\in T_k}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " ; learning rates " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\alpha ,\\beta" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " randomly initialized model " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_{W,\\Phi ,\\Theta} = \\mathbf{c}_W\\circ \\mathbf{h}_{\\Phi}\\circ \\mathbf{f}_{\\Theta}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " while not done do Randomly initialized adapter " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\mathbf{h}_{\\Phi}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " and classifier " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\mathbf{c}_W" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " Randomly sample " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "T_{k}^{\\prime} = \\{t_{1}^{\\prime},t_{2}^{\\prime},\\dots,t_{l}^{\\prime}\\}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "T_{k}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " and sample support and query sets " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\mathbf{S}_{\\mathrm{spt}}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\mathbf{S}_{\\mathrm{qry}}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t\\in T_k'}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " for " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "i = 1" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "l" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " do Estimate " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\hat{\\mu}_c^{t_i}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\hat{\\Sigma}^{t_i}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " by using " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " and Eq. (4); Sample virtual OOD samples " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "Z_{c}^{t_{i}}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " by Eq. (5); Compute " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\mathcal{L}^{t_i}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " using " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "S,S_{\\mathrm{spt}}^{t_i}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "Z_{c}^{t_{i}}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " by Eq. (7); Update parameters: " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "(\\Phi ,W)_{t_i + 1} = (\\Phi ,W)_{t_i} - \\alpha \\nabla \\mathcal{L}^{t_i}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " end for Compute " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{meta}}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " using " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\mathbf{S}_{\\mathrm{qry}}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " by Eq. (9); Update parameters: " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\Theta = \\Theta -\\beta \\nabla \\mathcal{L}_{\\mathrm{meta}}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " end while Output: initial model " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "G_{\\gamma}" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "(\\mathbf{x};s,\\mathbf{f}_{\\Theta ,\\Phi ,W})" + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "text", + "content": " by Eq. (1) meta-representation " + }, + { + "bbox": [ + 306, + 87, + 545, + 276 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_{\\Theta}" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "code_body" + } + ], + "index": 13, + "sub_type": "algorithm" + }, + { + "type": "code", + "bbox": [ + 306, + 307, + 545, + 441 + ], + "blocks": [ + { + "bbox": [ + 307, + 291, + 466, + 303 + ], + "lines": [ + { + "bbox": [ + 307, + 291, + 466, + 303 + ], + "spans": [ + { + "bbox": [ + 307, + 291, + 466, + 303 + ], + "type": "text", + "content": "Algorithm 2. MOL in Testing Process" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "code_caption" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "lines": [ + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "spans": [ + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": "Input: ID training samples " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t\\in T_K^-}" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": "; learning rates " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "\\alpha, \\beta" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": "; meta-representation " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_{\\Theta}" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": "; score function introduced in Eq. (2). while not done do \nRandomly initialized adapter " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "\\mathbf{h}_{\\Phi}" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": " and classifier " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "\\mathbf{c}_W" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": "; \nfor " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "i = K" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": " do \nEstimate " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "\\hat{\\mu}_c^{t_i}" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "\\hat{\\Sigma}^{t_i}" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": " by using " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": " and Eq. (4); \nSample virtual OOD samples " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "Z_c^{t_i}" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": " by Eq. (5); \nCompute " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "\\mathcal{L}^{t_i}" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": " using " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "S^{t_i}" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "Z_c^{t_i}" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": " by Eq. (7); \nUpdate parameters: " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "(\\Phi, W)_{t_{i+1}} = (\\Phi, W)_{t_i} - \\alpha \\nabla \\mathcal{L}^{t_i}" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": "; \nend for \nOutput: model " + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "inline_equation", + "content": "G_{\\gamma}(\\mathbf{x}; s, \\mathbf{f}_{\\Theta, \\Phi, W})" + }, + { + "bbox": [ + 306, + 307, + 545, + 441 + ], + "type": "text", + "content": " by Eq. (1). end while" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "code_body" + } + ], + "index": 15, + "sub_type": "algorithm" + }, + { + "bbox": [ + 306, + 449, + 545, + 473 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 449, + 545, + 473 + ], + "spans": [ + { + "bbox": [ + 306, + 449, + 545, + 473 + ], + "type": "text", + "content": "time period " + }, + { + "bbox": [ + 306, + 449, + 545, + 473 + ], + "type": "inline_equation", + "content": "T_{k}^{\\prime}" + }, + { + "bbox": [ + 306, + 449, + 545, + 473 + ], + "type": "text", + "content": ". Then, the optimization issue in outer-loop training can be represented as follows:" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 322, + 481, + 545, + 532 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 322, + 481, + 545, + 532 + ], + "spans": [ + { + "bbox": [ + 322, + 481, + 545, + 532 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\min _ {\\Theta} \\mathcal {L} _ {\\text {m e t a}} = \\min _ {\\Theta} \\left[ \\mathcal {L} _ {\\text {c e}} + \\mathcal {L} _ {\\text {q r y}} \\right. \\\\ \\left. + \\frac {1}{\\left| T _ {k} ^ {\\prime} \\right|} \\sum_ {t \\in T _ {k} ^ {\\prime}} \\left(\\mathcal {L} _ {\\mathrm {d}} ^ {t} + \\lambda \\mathcal {L} _ {\\mathrm {o o d}} ^ {t}\\right) \\right], \\tag {9} \\\\ \\end{array}", + "image_path": "a7555256d1cf7c0512c42f69c0e6c3fdd56aa0580cdd932711ef3239420c1acd.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 542, + 544, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 542, + 544, + 567 + ], + "spans": [ + { + "bbox": [ + 305, + 542, + 544, + 567 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 542, + 544, + 567 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{d}}^{t}" + }, + { + "bbox": [ + 305, + 542, + 544, + 567 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 542, + 544, + 567 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{ood}}^{t}" + }, + { + "bbox": [ + 305, + 542, + 544, + 567 + ], + "type": "text", + "content": " are computed by using the samples " + }, + { + "bbox": [ + 305, + 542, + 544, + 567 + ], + "type": "inline_equation", + "content": "S_{\\mathrm{qry}}^{t}" + }, + { + "bbox": [ + 305, + 542, + 544, + 567 + ], + "type": "text", + "content": " in the query set " + }, + { + "bbox": [ + 305, + 542, + 544, + 567 + ], + "type": "inline_equation", + "content": "\\mathbf{S}_{\\mathrm{qry}}" + }, + { + "bbox": [ + 305, + 542, + 544, + 567 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "spans": [ + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "type": "text", + "content": "In Eq. (9), the inner tasks (corresponding to " + }, + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{d}}^{t} + \\lambda \\mathcal{L}_{\\mathrm{odd}}^{t}" + }, + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "type": "text", + "content": ") across all time period " + }, + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "type": "inline_equation", + "content": "T_{k}^{\\prime}" + }, + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "type": "text", + "content": " are fed as one input (corresponding to " + }, + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "type": "inline_equation", + "content": "\\sum_{t\\in T_k'}\\left(\\mathcal{L}_{\\mathrm{d}}^t +\\lambda \\mathcal{L}_{\\mathrm{odd}}^t\\right) / |T_k^{\\prime}|" + }, + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "type": "text", + "content": ") in the outer-loop training. Thus, we are able to learn a good initialization of meta-representation " + }, + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "type": "inline_equation", + "content": "\\Theta" + }, + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "type": "text", + "content": " such that: when encountering a new distribution during testing, a few updating steps of " + }, + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "type": "inline_equation", + "content": "\\Phi ,W" + }, + { + "bbox": [ + 304, + 567, + 545, + 652 + ], + "type": "text", + "content": " result in a good performance." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "text", + "content": "Meta-testing. In the testing process, when exposed to previously unseen shifting distributions " + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "inline_equation", + "content": "D_{X_1Y_1}^t" + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "text", + "content": " (where " + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "inline_equation", + "content": "t \\in T_K^{-}" + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "text", + "content": "), we only need to fine-tune the adapter " + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{h}_{\\Phi}" + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "text", + "content": " and classifier " + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "inline_equation", + "content": "\\mathbf{c}_W" + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "text", + "content": " on the new test samples " + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "inline_equation", + "content": "S^t" + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "text", + "content": " (where " + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "inline_equation", + "content": "t \\in T_K^{-}" + }, + { + "bbox": [ + 304, + 664, + 545, + 715 + ], + "type": "text", + "content": "), while" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19357" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "type": "text", + "content": "keeping the meta-representation " + }, + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_{\\Theta}" + }, + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "type": "text", + "content": " fixed. This strategy enables fast adaptation by updating the lightweight classifier and adapter, which is useful for real-world online applications like self-driving agents. Furthermore, by incorporating the score function in Eq. (2), we can obtain an OOD detection model " + }, + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "type": "inline_equation", + "content": "g_{t}" + }, + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "type": "text", + "content": ", while updating " + }, + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "type": "inline_equation", + "content": "\\mathbf{h}_{\\Phi}" + }, + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "type": "inline_equation", + "content": "\\mathbf{c}_W" + }, + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "type": "text", + "content": " at each time " + }, + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "type": "inline_equation", + "content": "t \\in T_K^-" + }, + { + "bbox": [ + 46, + 72, + 289, + 157 + ], + "type": "text", + "content": " during the testing process." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 168, + 128, + 182 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 168, + 128, + 182 + ], + "spans": [ + { + "bbox": [ + 47, + 168, + 128, + 182 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 188, + 262, + 201 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 188, + 262, + 201 + ], + "spans": [ + { + "bbox": [ + 47, + 188, + 262, + 201 + ], + "type": "text", + "content": "5.1. Adaptive OOD Benchmark Construction" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 208, + 287, + 339 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 208, + 287, + 339 + ], + "spans": [ + { + "bbox": [ + 46, + 208, + 287, + 339 + ], + "type": "text", + "content": "For CAOOD evaluation, we construct 3 benchmarks (e.g., using Rotation MNIST, Cifar Corruption datasets as ID datasets) derived from commonly used static OOD benchmarks (e.g., MNIST, Cifar). Rotation MNIST and Corruption datasets are frequently used in continuous domain adaptation [53, 56]. In practical applications, rotation can replicate shifts arising from camera positions, while corruptions mimic various weather conditions (e.g., fog, snow) and movements (e.g., motion). In CAOOD, we evaluate both ID accuracy and OOD detection effectiveness. Dataset details are provided in the Appendix." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 339, + 287, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 339, + 287, + 434 + ], + "spans": [ + { + "bbox": [ + 46, + 339, + 287, + 434 + ], + "type": "text", + "content": "Rotation MNIST [5]. This dataset has MNIST digits with various rotations from " + }, + { + "bbox": [ + 46, + 339, + 287, + 434 + ], + "type": "inline_equation", + "content": "[0,180^{\\circ}]" + }, + { + "bbox": [ + 46, + 339, + 287, + 434 + ], + "type": "text", + "content": ", and for each rotation, there are 60,000 training images. In our benchmark, we use Rotation MNIST (R-MNIST) as the ID training dataset and evaluate the OOD detection performance on Rotation NOTMNIST (R-NOTMNIST) and Rotation Cifar10bw (R-Cifar10bw). There are no semantics overlaps between the ID and OOD datasets." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "spans": [ + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "content": "In our proposed MOL protocol, we consider images with rotation " + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "inline_equation", + "content": "0^{\\circ}" + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "content": " as the labeled original training samples " + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "content": ", and images from rotation " + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "inline_equation", + "content": "(0,180^{\\circ}]" + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "content": " as continuously shifting distributions over the whole time period " + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "inline_equation", + "content": "(0,T]" + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "content": ", i.e., " + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t\\in T}" + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "content": ". In meta-training, we use images from rotation " + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "inline_equation", + "content": "(0 - 60^{\\circ}]" + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t\\in T_k}" + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "content": ", and randomly sample " + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "inline_equation", + "content": "\\mathbf{S}_{\\mathrm{spt}}" + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "inline_equation", + "content": "\\mathbf{S}_{\\mathrm{qry}}" + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "content": " of length 10. During meta-testing, we update our model online for rotation " + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "inline_equation", + "content": "\\{S_{120^{\\circ}},S_{126^{\\circ}},i\\dots S_{174^{\\circ}}\\}" + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "content": ", i.e., " + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{T_K^-}" + }, + { + "bbox": [ + 46, + 436, + 287, + 544 + ], + "type": "text", + "content": " and for each rotation, we only use 100 training samples for adaptation." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 545, + 287, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 545, + 287, + 640 + ], + "spans": [ + { + "bbox": [ + 46, + 545, + 287, + 640 + ], + "type": "text", + "content": "Cifar10C. This dataset consists of 15 types of corruptions (e.g., fog, brightness, motion, noise) with each demonstrating 5 levels of severity. We use Cifar10C as the ID data and test on two near OOD datasets applying the same shifting distribution: TinyimageNetC, and Cifar100C. Following the OOD benchmark literature [63], we create TinyimageNetC from a subset of the Tinyimagenet [49] where 1207 images overlap semantic labels with Cifar10 are removed." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 642, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 287, + 713 + ], + "type": "text", + "content": "In our protocol, we take clean images from Cifar10 as original training samples " + }, + { + "bbox": [ + 46, + 642, + 287, + 713 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 46, + 642, + 287, + 713 + ], + "type": "text", + "content": ", and consider images with various corruptions from Cifar10C as samples come from shifting distributions. Specifically, we design the continuous shifting distributions by gradually changing the severity across all corruption types, for example:" + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 307, + 103, + 545, + 217 + ], + "blocks": [ + { + "bbox": [ + 305, + 71, + 545, + 95 + ], + "lines": [ + { + "bbox": [ + 305, + 71, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 305, + 71, + 545, + 95 + ], + "type": "text", + "content": "Table 1: OOD benchmarks used in our evaluation, including CAOD datasets, near OOD, and far OOD datasets." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 307, + 103, + 545, + 217 + ], + "lines": [ + { + "bbox": [ + 307, + 103, + 545, + 217 + ], + "spans": [ + { + "bbox": [ + 307, + 103, + 545, + 217 + ], + "type": "table", + "html": "
ID DatasetCAOODNear OODFar OOD
R-MNISTR-NOTMNISTNOTMNISTCifar10bw
R-Cifar10bw
Cifar10CCifar100CCifar100Textures
TinyimagenetCTinyimageNetLSUN iSUN
Cifar100CCifar10CCifar10Textures
TinyimagenetCTinyimageNetLSUN iSUN
", + "image_path": "addd95e4937ab6063ae83a0ef947a87c4eb012f4af761bc754b00fbec86c6d9e.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 307, + 222, + 541, + 249 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 222, + 541, + 249 + ], + "spans": [ + { + "bbox": [ + 307, + 222, + 541, + 249 + ], + "type": "interline_equation", + "content": "\\underbrace {\\cdots , \\mathrm {C} _ {t - 1} ^ {5}} _ {\\text {t - 1 a n d b e f o r e}} \\rightarrow \\underbrace {\\mathrm {C} _ {t} ^ {1} , \\mathrm {C} _ {t} ^ {2} , \\mathrm {C} _ {t} ^ {3} , \\mathrm {C} _ {t} ^ {4} , \\mathrm {C} _ {t} ^ {5} , \\mathrm {C} _ {t} ^ {4} , \\mathrm {C} _ {t} ^ {3} , \\mathrm {C} _ {t} ^ {2} , \\mathrm {C} _ {t} ^ {1}} _ {\\text {c o r r u p t i o n t y p e t , c h a n g i n g g r a d u a l l y}} \\rightarrow \\underbrace {\\mathrm {C} _ {t + 1} ^ {1} , \\mathrm {C} _ {t + 1} ^ {2} , \\cdots} _ {\\text {t + 1 a n d o n}}", + "image_path": "68c8df58e9c80ddc11ca4745ade0a9ebe70ba7093a197a5f55d43ded45b60271.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "spans": [ + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "type": "text", + "content": "In meta-training, we randomly sample " + }, + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "type": "inline_equation", + "content": "\\mathbf{S}_{\\mathrm{spt}}" + }, + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "type": "inline_equation", + "content": "\\mathbf{S}_{\\mathrm{qry}}" + }, + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "type": "text", + "content": " of length 10 (i.e., " + }, + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "type": "inline_equation", + "content": "|T_k'| = 10" + }, + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "type": "text", + "content": "), from the first 7 corruptions of 63 continuously shifting distributions, i.e., " + }, + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t \\in T_k}" + }, + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "type": "inline_equation", + "content": "|T_k| = 63" + }, + { + "bbox": [ + 305, + 250, + 545, + 357 + ], + "type": "text", + "content": ". In meta-testing, we adapt our model to a trajectory of length 10 that is randomly sampled from the last 7 corruptions and evaluate on unseen test images from the last 7 corruptions (i.e., frost, fog, brightness, contrast, elastic transform, pixelate, jpeg compression). Similarly, we only had access to 100 training samples in meta-testing." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 358, + 545, + 453 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 358, + 545, + 453 + ], + "spans": [ + { + "bbox": [ + 304, + 358, + 545, + 453 + ], + "type": "text", + "content": "Cifar100C [16]. This dataset is a variant of Cifar10C by applying the same corruptions to Cifar100. We used Cifar100C as the ID dataset and two near OOD datasets with the same continuous shifting distributions: Cifar10C and TinyImageNetC. We re-create TinyImageNetC after 2505 images sharing the same classes with Cifar100 have been removed [63]. For the MOL protocol, we applied the same training and testing fashion as used in Cifar10C." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 454, + 545, + 525 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 454, + 545, + 525 + ], + "spans": [ + { + "bbox": [ + 304, + 454, + 545, + 525 + ], + "type": "text", + "content": "Standard OOD Datasets. In addition, we evaluate our method's OOD detection performance on commonly used OOD datasets from a static distribution, including Cifar10 and Cifar100 [26], TinyImageNet [49], Textures [27], LSUN-Resize, LSUN-Crop [66], and iSUN [61]. Table 1 summarizes evaluated OOD detection benchmarks." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 536, + 430, + 548 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 536, + 430, + 548 + ], + "spans": [ + { + "bbox": [ + 306, + 536, + 430, + 548 + ], + "type": "text", + "content": "5.2. Baselines and Metrics" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 555, + 545, + 639 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 555, + 545, + 639 + ], + "spans": [ + { + "bbox": [ + 304, + 555, + 545, + 639 + ], + "type": "text", + "content": "We compare our method with comprehensive OOD detection baselines including Maximum Softmax Probability [17], ODIN [32], Mahalanobis distance [29], energy score [34], Gram Metrics [45], Gradnorm [19], and the recent VOS [8], KNN [47] and LogitNorm [60]. To apply the above static OOD detection baselines in CAOOD, we use three different training/adapting schemes as follows." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 639, + 545, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 639, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 304, + 639, + 545, + 677 + ], + "type": "text", + "content": "Direct Test. The model is trained on the labeled original training samples " + }, + { + "bbox": [ + 304, + 639, + 545, + 677 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 304, + 639, + 545, + 677 + ], + "type": "text", + "content": " and then directly test on continuously shifting " + }, + { + "bbox": [ + 304, + 639, + 545, + 677 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t\\in T_K^-}" + }, + { + "bbox": [ + 304, + 639, + 545, + 677 + ], + "type": "text", + "content": " for OOD detection with no adaptation." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "content": "Simple Adaptive. During training, the model is trained on the labeled original training samples " + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "content": ". During testing, we finetune the classifier of the model to adapt to continuously" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19358" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 46, + 128, + 548, + 251 + ], + "blocks": [ + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "lines": [ + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "text", + "content": "Table 2: Main Results on Rotation MNIST. " + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "inline_equation", + "content": "\\uparrow" + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "text", + "content": " (or " + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "inline_equation", + "content": "\\downarrow" + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "text", + "content": ") indicates greater (or smaller) values are preferred. For each comparable method, we report results on Direct Test / Simple Adaptive / Domain Adaptation. Only Direct Test results are reported for Gram and KNN, only Direct Test and Simple Adaptive results are reported for VOS and LogitNorm. The bold and * represent the best and second best performance and the shadow part marks our method." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 46, + 128, + 548, + 251 + ], + "lines": [ + { + "bbox": [ + 46, + 128, + 548, + 251 + ], + "spans": [ + { + "bbox": [ + 46, + 128, + 548, + 251 + ], + "type": "table", + "html": "
MethodRotation NOTMNISTRotation Cifar10bwAverageID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
MSP76.9 / 75.9 / 62.371.9 / 70.4 / 87.690.1 / 89.4 / 68.855.6 / 48.5 / 83.683.5 / 82.6 / 65.664.8 / 59.5 / 85.625.6 / 28.3 / 27.2
ODIN63.6 / 76.7 / 30.885.2 / 72.6 / 56.787.3 / 88.1 / 67.658.2 / 50.9 / 83.975.5 / 82.4 / 49.271.7 / 61.8 / 70.325.6 / 28.3 / 27.2
Mahalanobis61.2 / 75.4 / 32.986.1 / 75.1 / 56.989.3 / 90.1 / 66.758.1 / 49.5 / 80.875.3 / 82.8 / 49.872.1 / 62.3 / 68.925.6 / 28.4 / 27.7
Energy92.6 / 91.7 / 72.736.1 / 39.7 / 76.197.5 / 95.9 / 69.112.6 / 19.9 / 85.295.1 / 93.8 / 70.924.4 / 29.8 / 80.725.6 / 28.3 / 27.2
Gram96.1*10.698.9*4.6*97.5*7.625.6
VOS86.7 / 93.557.6 / 32.392.7 / 96.731.0 / 16.489.7 / 95.144.3 / 24.427.7 / 30.9
LogitNorm84.0 / 94.046.2 / 29.797.7 / 99.010.5 / 4.590.0 / 96.528.3 / 17.124.7 / 31.5*
KNN95.716.591.425.093.520.824.9
MOL96.513.9*98.9*9.297.711.5*35.6
", + "image_path": "c9b864585ababa09f49f1670459f643d1d5007cc0676882edee1fdcb7f5eaa65.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "table", + "bbox": [ + 46, + 316, + 548, + 449 + ], + "blocks": [ + { + "bbox": [ + 46, + 259, + 547, + 309 + ], + "lines": [ + { + "bbox": [ + 46, + 259, + 547, + 309 + ], + "spans": [ + { + "bbox": [ + 46, + 259, + 547, + 309 + ], + "type": "text", + "content": "Table 3: Main Results on Cifar10 corruption. " + }, + { + "bbox": [ + 46, + 259, + 547, + 309 + ], + "type": "inline_equation", + "content": "\\uparrow" + }, + { + "bbox": [ + 46, + 259, + 547, + 309 + ], + "type": "text", + "content": " (or " + }, + { + "bbox": [ + 46, + 259, + 547, + 309 + ], + "type": "inline_equation", + "content": "\\downarrow" + }, + { + "bbox": [ + 46, + 259, + 547, + 309 + ], + "type": "text", + "content": ") indicates greater (or smaller) values are preferred. For each comparable method, we report results on Direct Test / Simple Adaptive / Domain Adaptation. Only Direct Test results are reported for Gram, Gradnorm, and KNN, only Direct Test and Simple Adaptive results are reported for VOS and LogitNorm. The bold and * represent the best performance and the shadow part marks our method." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 46, + 316, + 548, + 449 + ], + "lines": [ + { + "bbox": [ + 46, + 316, + 548, + 449 + ], + "spans": [ + { + "bbox": [ + 46, + 316, + 548, + 449 + ], + "type": "table", + "html": "
MethodCifar100CTinyImagenetCAverageID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
MSP53.2 / 62.2 / 54.894.3 / 91.6 / 92.959.7 / 64.0 / 52.992.5 / 91.2 / 94.956.5 / 63.1 / 53.893.4 / 91.4 / 93.938.5 / 56.2 / 35.6
ODIN46.1 / 61.3 / 55.296.5 / 91.9 / 93.440.3 / 62.9 / 52.099.1 / 91.5 / 94.943.2 / 62.1 / 53.697.8 / 91.7 / 94.238.1 / 55.6 / 35.2
Mahalanobis46.8 / 63.6 / 55.196.7 / 91.3 / 93.447.0 / 66.0 / 53.698.1 / 90.6 / 93.946.9 / 64.8 / 54.497.4 / 90.9 / 93.738.5 / 56.2 / 35.6
Energy52.7 / 60.8 / 56.594.4 / 91.4 / 93.761.5 / 65.0 / 60.891.6 / 89.0 / 94.657.1 / 62.9 / 58.793.0 / 90.2 / 94.238.5 / 52.9 / 35.6
Gram55.289.766.582.560.986.1*38.1
Gradnorm29.597.241.396.535.496.938.5
VOS52.6 / 53.695.7 / 96.557.3 / 59.997.2 / 97.154.9 / 56.896.5 / 96.825.9 / 31.7
LogitNorm56.4 / 65.3*94.5 / 88.9*61.9 / 67.6*92.6 / 85.959.1 / 66.4*93.6 / 87.443.5 / 59.1*
KNN54.194.457.793.555.994.044.2
MOL69.786.371.485.6*70.685.964.1
", + "image_path": "70ee12503978a90771cd0392fbb8f7f3259ad55c03093b9b18c8dbd2e0b52983.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_body" + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 468, + 287, + 518 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 468, + 287, + 518 + ], + "spans": [ + { + "bbox": [ + 46, + 468, + 287, + 518 + ], + "type": "text", + "content": "shifting " + }, + { + "bbox": [ + 46, + 468, + 287, + 518 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t\\in T_K^-}" + }, + { + "bbox": [ + 46, + 468, + 287, + 518 + ], + "type": "text", + "content": " dynamically and test their performance. Specifically, the classifier is updated using our proposed meta-testing strategy without virtual OOD generation and uncertainty regularization (i.e., by using Eq. 3)." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 519, + 287, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 519, + 287, + 628 + ], + "spans": [ + { + "bbox": [ + 46, + 519, + 287, + 628 + ], + "type": "text", + "content": "Domain Adaptation. The model is trained using classic domain adaptation techniques DAN [36]. Specifically, in the training process, we train the model offline by viewing " + }, + { + "bbox": [ + 46, + 519, + 287, + 628 + ], + "type": "inline_equation", + "content": "S" + }, + { + "bbox": [ + 46, + 519, + 287, + 628 + ], + "type": "text", + "content": " as the source domain and all shifting training samples " + }, + { + "bbox": [ + 46, + 519, + 287, + 628 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t \\in T_k}" + }, + { + "bbox": [ + 46, + 519, + 287, + 628 + ], + "type": "text", + "content": " available as the target domain. During testing, we finetune the classifier of the model to adapt to continuously shifting " + }, + { + "bbox": [ + 46, + 519, + 287, + 628 + ], + "type": "inline_equation", + "content": "\\{S^t\\}_{t \\in T_K^-}" + }, + { + "bbox": [ + 46, + 519, + 287, + 628 + ], + "type": "text", + "content": " dynamically and test their performance (Eq. (3)). By doing so the Domain Adaptation strategy violates the CAOD setting during training." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "content": "Note that for Gram Metrics, Gradnorm, and KNN, only the Direct Test results are reported because their scoring functions are calculated based on feature representations across all layers, which demands a finetuning on the whole model during testing. For VOS and LogitNorm, only Direct Test and Simple Adaptive results are reported, as we found it difficult to train them with Domain Adaptation strategy." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 468, + 547, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 468, + 547, + 601 + ], + "spans": [ + { + "bbox": [ + 304, + 468, + 547, + 601 + ], + "type": "text", + "content": "Evaluation Metrics. For OOD detection evaluation, we report 1) the area under the receiver operating characteristic curve (AUROC), which measures the model's capacity to distinguish ID and OOD samples based on varying thresholds of the predicted confidence scores; and 2) the false positive rate (FPR95) of OOD samples when the true positive rate of ID samples is fixed at " + }, + { + "bbox": [ + 304, + 468, + 547, + 601 + ], + "type": "inline_equation", + "content": "95\\%" + }, + { + "bbox": [ + 304, + 468, + 547, + 601 + ], + "type": "text", + "content": ", which measures the percentage of OOD samples that are incorrectly classified as ID samples when the model's sensitivity to ID samples is high. For evaluating the ID classification, we report the commonly used accuracy." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 610, + 440, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 610, + 440, + 624 + ], + "spans": [ + { + "bbox": [ + 306, + 610, + 440, + 624 + ], + "type": "text", + "content": "5.3. Implementation Details" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": "On the R-MNIST dataset, we use LeNet as the backbone for all models. As for Cifar10C and Cifar100C datasets, we use WideResNet as the backbone. Note that in our method, the last fully connected layers of LeNet and WideResNet are removed for learning meta-representation during training. We set the uncertainty regularization balancing term " + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 304, + 629, + 547, + 715 + ], + "type": "text", + "content": " as 0.015 for R-MNIST, and 0.1 for two CifarC datasets. The" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 758 + ], + "type": "text", + "content": "19359" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 46, + 128, + 548, + 245 + ], + "blocks": [ + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "lines": [ + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "spans": [ + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "text", + "content": "Table 4: Main Results on Cifar100 corruption. " + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "inline_equation", + "content": "\\uparrow" + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "text", + "content": " (or " + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "inline_equation", + "content": "\\downarrow" + }, + { + "bbox": [ + 46, + 70, + 547, + 120 + ], + "type": "text", + "content": ") indicates greater (or smaller) values are preferred. For each comparable method, we report results on Direct Test / Simple Adaptive / Domain Adaptation (DA). Only Direct Test results are reported for Gram, Gradnorm, and KNN, only Direct Test and Simple Adaptive results are reported for VOS and LogitNorm. The bold and * represent the best performance and the shadow part marks our method." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 46, + 128, + 548, + 245 + ], + "lines": [ + { + "bbox": [ + 46, + 128, + 548, + 245 + ], + "spans": [ + { + "bbox": [ + 46, + 128, + 548, + 245 + ], + "type": "table", + "html": "
MethodTinyImagenetCCifar10CAverageID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
MSP50.9 / 61.3 / 58.194.8 / 91.3 / 92.558.2 / 64.0 / 61.292.9 / 91.2 / 91.354.6 / 62.7* / 59.793.4 / 91.3 / 91.927.8 / 41.4 / 37.7
ODIN49.1 / 59.7 / 55.595.5 / 91.4 / 93.641.8 / 63.5 / 60.298.0 / 90.8* / 91.645.5 / 61.6 / 57.996.8 / 91.1* / 92.227.8 / 41.4 / 37.7
Mahalanobis48.597.140.499.044.598.127.8
Energy50.7 / 58.0 / 61.6*94.9 / 92.1 / 91.0*58.7 / 63.6* / 61.092.9 / 91.4 / 92.654.7 / 60.8 / 61.393.9 / 91.8 / 91.827.8 / 41.4 / 37.7
Gram47.195.949.695.648.495.827.8
VOS49.9 / 52.196.0 / 96.352.6 / 54.897.7 / 98.051.3 / 53.596.9 / 97.226.1 / 43.1*
LogitNorm53.0 / 58.394.1 / 92.258.8 / 63.193.2 / 91.955.9 / 60.793.7 / 92.023.4 / 38.5
KNN51.795.150.094.950.995.022.9
MOL69.488.763.189.066.388.957.4
", + "image_path": "1b43db9760692adcb08b148002171b29068808e0acfeec78060f19d366e9b07d.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 97, + 260, + 211, + 357 + ], + "blocks": [ + { + "bbox": [ + 97, + 260, + 211, + 357 + ], + "lines": [ + { + "bbox": [ + 97, + 260, + 211, + 357 + ], + "spans": [ + { + "bbox": [ + 97, + 260, + 211, + 357 + ], + "type": "image", + "image_path": "8e8faf2e11dddf91e67a7a1d03a739e9d2d19c88f7b9cb5dfdb2fcc91c478a9d.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 364, + 547, + 390 + ], + "lines": [ + { + "bbox": [ + 46, + 364, + 547, + 390 + ], + "spans": [ + { + "bbox": [ + 46, + 364, + 547, + 390 + ], + "type": "text", + "content": "Figure 3: The ID classification (a) and OOD detection performance (b-c) on R-MNIST benchmark over continuously shifting distributions. Our method achieved the best performance on all unseen distributions, i.e., the pink line." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 242, + 260, + 354, + 357 + ], + "blocks": [ + { + "bbox": [ + 242, + 260, + 354, + 357 + ], + "lines": [ + { + "bbox": [ + 242, + 260, + 354, + 357 + ], + "spans": [ + { + "bbox": [ + 242, + 260, + 354, + 357 + ], + "type": "image", + "image_path": "405aa6acccfb98056eb25cd8223fc29799c06afdd5810045d20a0229624c4e55.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 386, + 260, + 497, + 357 + ], + "blocks": [ + { + "bbox": [ + 386, + 260, + 497, + 357 + ], + "lines": [ + { + "bbox": [ + 386, + 260, + 497, + 357 + ], + "spans": [ + { + "bbox": [ + 386, + 260, + 497, + 357 + ], + "type": "image", + "image_path": "a52959edae6a3bd0f9103c4d107ee82d0cc4beba612dcc2416c5c94d9e21a8f5.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 47, + 439, + 287, + 492 + ], + "blocks": [ + { + "bbox": [ + 47, + 406, + 287, + 430 + ], + "lines": [ + { + "bbox": [ + 47, + 406, + 287, + 430 + ], + "spans": [ + { + "bbox": [ + 47, + 406, + 287, + 430 + ], + "type": "text", + "content": "Table 5: Average results over 10 randomly sampled trajectories on R-MNIST." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 47, + 439, + 287, + 492 + ], + "lines": [ + { + "bbox": [ + 47, + 439, + 287, + 492 + ], + "spans": [ + { + "bbox": [ + 47, + 439, + 287, + 492 + ], + "type": "table", + "html": "
MethodR-NOTMNISTR-Cifar10bwID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
Fixed97.913.998.99.235.6
Sampled97.7 ±0.413.6 ±0.898.8 ±0.49.6 ±0.736.7 ±1.4
", + "image_path": "8a4ce91824030830306b12ed95e1dcac9e38eaedd186cb36e0985a3eb2c64e8a.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 47, + 560, + 287, + 651 + ], + "blocks": [ + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "lines": [ + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "spans": [ + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "text", + "content": "Table 6: Ablation study on R-MNIST, where w/o " + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{ood}}" + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "text", + "content": " and w/o " + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{qry}}" + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "text", + "content": " are variants trained without " + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{ood}}" + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{qry}}" + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "text", + "content": ". E indicates the adding point of " + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{ood}}" + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "text", + "content": ", e.g., " + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "inline_equation", + "content": "1/2" + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "text", + "content": " indicates adding " + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{ood}}" + }, + { + "bbox": [ + 47, + 502, + 287, + 552 + ], + "type": "text", + "content": " halfway through training." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 47, + 560, + 287, + 651 + ], + "lines": [ + { + "bbox": [ + 47, + 560, + 287, + 651 + ], + "spans": [ + { + "bbox": [ + 47, + 560, + 287, + 651 + ], + "type": "table", + "html": "
MethodR-NOTMNISTR-Cifar10bwID Accuracy
AUROC ↑FPR95 ↓AUROC ↑FPR95 ↓
w/o Lood94.134.997.612.234.2
w/o Lqry93.935.196.914.332.2
E = 1/399.77.499.95.628.7
E = 1/298.010.499.18.730.1
E = 2/396.513.998.99.235.6
E = 4/595.315.595.216.335.9
", + "image_path": "9100439f2456c232115fdd10d2a15fb88fb3bc23b2c2c35923883efe71104546.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "content": "learning rates in inner/outer loops are set as 0.1/0.01 for R-MNIST, and 0.3/0.03 for two CIFarC datasets, respectively. We use SGD with 0.9 momentum and " + }, + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "inline_equation", + "content": "5 \\times 10^{-4}" + }, + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "content": " weight decay. On each OOD benchmark, all methods are trained us-" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 408, + 538, + 421 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 408, + 538, + 421 + ], + "spans": [ + { + "bbox": [ + 306, + 408, + 538, + 421 + ], + "type": "text", + "content": "ing the same backbones with the same number of epochs." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 430, + 430, + 443 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 430, + 430, + 443 + ], + "spans": [ + { + "bbox": [ + 306, + 430, + 430, + 443 + ], + "type": "text", + "content": "5.4. Experimental Results" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 449, + 545, + 593 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 449, + 545, + 593 + ], + "spans": [ + { + "bbox": [ + 304, + 449, + 545, + 593 + ], + "type": "text", + "content": "Results on R-MNIST. Table 2 summarizes the ID classification and OOD detection results on R-MNIST. The baseline results show that most existing static OOD detection methods cannot handle ID classification and OOD detection when test samples compass continuous distribution shifts. By using an alternate scheme when we fine-tune the model's classifier during testing (i.e., Simple Adaptive), the comparable methods improved around " + }, + { + "bbox": [ + 304, + 449, + 545, + 593 + ], + "type": "inline_equation", + "content": "2.7\\%" + }, + { + "bbox": [ + 304, + 449, + 545, + 593 + ], + "type": "text", + "content": " in ID accuracy and reduced from " + }, + { + "bbox": [ + 304, + 449, + 545, + 593 + ], + "type": "inline_equation", + "content": "5.3\\%" + }, + { + "bbox": [ + 304, + 449, + 545, + 593 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 449, + 545, + 593 + ], + "type": "inline_equation", + "content": "19.3\\%" + }, + { + "bbox": [ + 304, + 449, + 545, + 593 + ], + "type": "text", + "content": " in FPR95 across all baselines. Such improvement endorses the dynamic adaptation of the OOD detection model when test samples come from continuously shifting distribution." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": "When examining the performance of the Domain Adaptation strategy, results show that ID accuracy improved over the Direct Test baselines, however, the OOD detection performance dropped heavily, from " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "17.9\\%" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "26.3\\%" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": " across all methods in AUROC. In contrast to the Domain Adaptation strategy, our method obtained superior performance (ID accuracy: " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "35.6\\%" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": ", AUROC: " + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "97.7\\%" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": ") by respecting the continuous shifting characteristic of test distributions. Note that although Gram [45] obtained the best results in FPR95, their ID accuracy (" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 304, + 594, + 547, + 715 + ], + "type": "text", + "content": " lower than our method) questioned the" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "19360" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 286, + 83 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 286, + 83 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 286, + 83 + ], + "type": "text", + "content": "reliability of the OOD detection performance in CAOOD." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "spans": [ + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "text", + "content": "Results on Cifar Corruption. Table 3 and 4 show the OOD detection results on Cifar10C and Cifar100C. Results show that MOL achieved the best performance on both Cifar corruption benchmarks. On Cifar10C, we outperformed Direct Test, Simple Adaptive, and Domain Adaptation strategies by " + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "inline_equation", + "content": "25.6\\%" + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "inline_equation", + "content": "7.9\\%" + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "inline_equation", + "content": "28.5\\%" + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "text", + "content": " in ID classification respectively. For OOD detection, we outperformed most comparable methods and adaptation strategies. Our AUROC outperformed the second-best result (i.e., Simple Adaptive LogitNorm) by " + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "inline_equation", + "content": "4.2\\%" + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "text", + "content": ". On Cifar100C, we improved the 3 adaptation strategies by " + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "inline_equation", + "content": "29.6\\%" + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "inline_equation", + "content": "16.0\\%" + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "inline_equation", + "content": "19.7\\%" + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "text", + "content": " respectively in ID accuracy, while maintaining the best average OOD detection performance when compared to all other methods. Note that in our reproduction, Gram shows a catastrophic OOD performance drop and Gradnorm obtained a " + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "inline_equation", + "content": "100\\%" + }, + { + "bbox": [ + 46, + 84, + 286, + 300 + ], + "type": "text", + "content": " in FPR95 when tested on the Cifar100C benchmark, which indicates the instability of their scoring functions using gradients/features across all layers when applied in CAOOD." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 301, + 286, + 408 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 301, + 286, + 408 + ], + "spans": [ + { + "bbox": [ + 46, + 301, + 286, + 408 + ], + "type": "text", + "content": "Performance on Continuously Shifting Distribution. Figure 3 shows the ID classification and AUROC over distributions on the Rotation MNIST benchmark. It is clear to see that the OOD detection performance of VOS and Energy decreased when the distribution continues to shift, while our method maintained a good OOD detection (i.e., the purple line). This further endorses our method's superiority in addressing the CAOOD problem by learning to quickly adapt to newly arriving test samples with shifting distributions." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 410, + 286, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 410, + 286, + 601 + ], + "spans": [ + { + "bbox": [ + 46, + 410, + 286, + 601 + ], + "type": "text", + "content": "Discussion on the impact of Discretization. Theoretically, modeling in continuous time intervals requires infinite samples, making it unrealistic. As such discretization (using finite samples to simulate infinite samples) is a common way to address continuous domain adaptation [56, 2]. CIDA [53] employs closed intervals which uniformly sample finite time points from these intervals and obtain training data for each sampled time point. Following CIDA, instead of adapting to one fixed discretized trajectory, in meta-training, we adapt to randomly sampled trajectories (i.e., " + }, + { + "bbox": [ + 46, + 410, + 286, + 601 + ], + "type": "inline_equation", + "content": "\\mathbf{S}_{\\mathrm{spt}}, \\mathbf{S}_{\\mathrm{qry}}" + }, + { + "bbox": [ + 46, + 410, + 286, + 601 + ], + "type": "text", + "content": ") to approximate from " + }, + { + "bbox": [ + 46, + 410, + 286, + 601 + ], + "type": "inline_equation", + "content": "0^{\\circ}" + }, + { + "bbox": [ + 46, + 410, + 286, + 601 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 410, + 286, + 601 + ], + "type": "inline_equation", + "content": "60^{\\circ}" + }, + { + "bbox": [ + 46, + 410, + 286, + 601 + ], + "type": "text", + "content": ". To further evaluate the impact of discretization on detection accuracy, we evaluate our method on 10 randomly sampled trajectories during testing. Table 5 shows the average results suggesting that the detection performance remains stable across various trajectories (fixed and sampled)." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 610, + 140, + 623 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 610, + 140, + 623 + ], + "spans": [ + { + "bbox": [ + 47, + 610, + 140, + 623 + ], + "type": "text", + "content": "5.5. Ablation Study" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "type": "text", + "content": "A brief ablation analysis is provided in Table 6. Firstly, we build a variant of our model without " + }, + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{ood}}" + }, + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "type": "text", + "content": " by taking out the uncertainty regularization term " + }, + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{ood}}" + }, + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "type": "text", + "content": " so it reduces to focus solely on continuous ID adaptation without synthesizing virtual OOD samples for uncertainty regularization. By doing so the ID accuracy slightly dropped by " + }, + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "type": "inline_equation", + "content": "1.4\\%" + }, + { + "bbox": [ + 46, + 629, + 286, + 713 + ], + "type": "text", + "content": " while the OOD detection performance decreases noticeably (3.8% in" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "text", + "content": "AUROC). Then, we conduct experiments on another variant without " + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{qry}}" + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "text", + "content": " without the constraint term on distribution discrepancy " + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{qry}}" + }, + { + "bbox": [ + 304, + 72, + 545, + 228 + ], + "type": "text", + "content": ", leading to performance drops on all ID accuracy, AUROC, and FPR95. This reflects that harnessing knowledge transfer between distributions is indispensable to the CAOD problem. Further, we studied the impact on starting point of uncertainty regularization during the whole training process. Results show that an earlier start resulted in a significant drop in ID accuracy while the OOD detection performance is good but meaningless. We suggest that a balance should be identified whenever the ID accuracy is prioritized. More ablations, experimental results, and comparisons about training/testing time refer to the Appendix." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 236, + 475, + 249 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 236, + 475, + 249 + ], + "spans": [ + { + "bbox": [ + 305, + 236, + 475, + 249 + ], + "type": "text", + "content": "6. Conclusion and Future Works" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 256, + 545, + 376 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 256, + 545, + 376 + ], + "spans": [ + { + "bbox": [ + 304, + 256, + 545, + 376 + ], + "type": "text", + "content": "OOD detection has achieved great progress while facing challenges in real-world scenarios when test samples exhibit dynamic distribution shifting. Motivated by these challenges, we propose a novel and more realistic CAOD detection and develop an effective method of MOL in addressing this problem. To the best of our knowledge, we are the first to investigate OOD detection under continuous distribution shifts. Our proposal will motivate future works to pursue new methods in addressing real-world OOD detection under continuously shifting distributions." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 385, + 365, + 398 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 385, + 365, + 398 + ], + "spans": [ + { + "bbox": [ + 306, + 385, + 365, + 398 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 310, + 405, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 17, + "blocks": [ + { + "bbox": [ + 310, + 405, + 545, + 447 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 405, + 545, + 447 + ], + "spans": [ + { + "bbox": [ + 310, + 405, + 545, + 447 + ], + "type": "text", + "content": "[1] Abhijit Bendale and Terrance Boult. Towards open world recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 1893-1902, 2015." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 311, + 449, + 545, + 482 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 449, + 545, + 482 + ], + "spans": [ + { + "bbox": [ + 311, + 449, + 545, + 482 + ], + "type": "text", + "content": "[2] Andreea Bobu, Eric Tzeng, Judy Hoffman, and Trevor Darryll. Adapting to continuously shifting domains. In International Conference on Learning Representations, 2018." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 311, + 483, + 545, + 548 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 483, + 545, + 548 + ], + "spans": [ + { + "bbox": [ + 311, + 483, + 545, + 548 + ], + "type": "text", + "content": "[3] Jiefeng Chen, Yixuan Li, Xi Wu, Yingyu Liang, and Somesh Jha. Atom: Robustifying out-of-distribution detection using outlier mining. In Machine Learning and Knowledge Discovery in Databases. Research Track: European Conference, ECML PKDD 2021, Bilbao, Spain, September 13-17, 2021, Proceedings, Part III 21, pages 430-445. Springer, 2021." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 311, + 548, + 545, + 591 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 548, + 545, + 591 + ], + "spans": [ + { + "bbox": [ + 311, + 548, + 545, + 591 + ], + "type": "text", + "content": "[4] Rui Dai, Yonggang Zhang, Zhen Fang, Bo Han, and Xinmei Tian. Moderately distributional exploration for domain generalization. International Conference on Machine Learning, 2023." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 311, + 593, + 545, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 593, + 545, + 624 + ], + "spans": [ + { + "bbox": [ + 311, + 593, + 545, + 624 + ], + "type": "text", + "content": "[5] Li Deng. The mnist database of handwritten digit images for machine learning research. IEEE Signal Processing Magazine, 29(6):141-142, 2012." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 311, + 625, + 545, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 625, + 545, + 679 + ], + "spans": [ + { + "bbox": [ + 311, + 625, + 545, + 679 + ], + "type": "text", + "content": "[6] Jiahua Dong, Yang Cong, Gan Sun, Zhen Fang, and Zhengming Ding. Where and how to transfer: Knowledge aggregation-induced transferability perception for unsupervised domain adaptation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 1(2):1-18, 2021." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 311, + 681, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 681, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 311, + 681, + 545, + 713 + ], + "type": "text", + "content": "[7] Jiahua Dong, Yang Cong, Gan Sun, Bineng Zhong, and Xiaowei Xu. What can be transferred: Unsupervised domain adaptation for endoscopic lesions segmentation. In" + } + ] + } + ], + "index": 16 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19361" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 73, + 286, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 67, + 73, + 286, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 73, + 286, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 73, + 286, + 95 + ], + "type": "text", + "content": "IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), pages 4022-4031, June 2020." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 53, + 96, + 286, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 96, + 286, + 139 + ], + "spans": [ + { + "bbox": [ + 53, + 96, + 286, + 139 + ], + "type": "text", + "content": "[8] Xuefeng Du, Zhaoning Wang, Mu Cai, and Yixuan Li. Vos: Learning what you don't know by virtual outlier synthesis. In International Conference on Learning Representations, 2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 141, + 286, + 195 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 141, + 286, + 195 + ], + "spans": [ + { + "bbox": [ + 53, + 141, + 286, + 195 + ], + "type": "text", + "content": "[9] Thomas Elsken, Benedikt Staffler, Jan Hendrik Metzen, and Frank Hutter. Meta-learning of neural architectures for few-shot learning. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12365-12375, 2020." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 198, + 286, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 198, + 286, + 239 + ], + "spans": [ + { + "bbox": [ + 48, + 198, + 286, + 239 + ], + "type": "text", + "content": "[10] Zhen Fang, Yixuan Li, Jie Lu, Jiahua Dong, Bo Han, and Feng Liu. Is out-of-distribution detection learnable? Advances in Neural Information Processing Systems, 35:37199-37213, 2022." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 243, + 286, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 243, + 286, + 285 + ], + "spans": [ + { + "bbox": [ + 48, + 243, + 286, + 285 + ], + "type": "text", + "content": "[11] Zhen Fang, Jie Lu, Anjin Liu, Feng Liu, and Guangquan Zhang. Learning bounds for open-set learning. In International Conference on Machine Learning, pages 3122-3132. PMLR, 2021." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 287, + 286, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 287, + 286, + 330 + ], + "spans": [ + { + "bbox": [ + 48, + 287, + 286, + 330 + ], + "type": "text", + "content": "[12] Zhen Fang, Jie Lu, Feng Liu, and Guangquan Zhang. Semi-supervised heterogeneous domain adaptation: Theory and algorithms. IEEE Transactions on Pattern Analysis and Machine Intelligence, 45(1):1087-1105, 2023." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 332, + 286, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 332, + 286, + 374 + ], + "spans": [ + { + "bbox": [ + 48, + 332, + 286, + 374 + ], + "type": "text", + "content": "[13] Chelsea Finn, Pieter Abbeel, and Sergey Levine. Model-agnostic meta-learning for fast adaptation of deep networks. In International Conference on Machine Learning, pages 1126–1135. PMLR, 2017." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 377, + 286, + 431 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 377, + 286, + 431 + ], + "spans": [ + { + "bbox": [ + 48, + 377, + 286, + 431 + ], + "type": "text", + "content": "[14] Yaroslav Ganin, Evgeniya Ustinova, Hana Ajakan, Pascal Germain, Hugo Larochelle, François Laviolette, Mario Marchand, and Victor Lempitsky. Domain-adversarial training of neural networks. The journal of machine learning research, 17(1):2096-2030, 2016." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 434, + 286, + 475 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 434, + 286, + 475 + ], + "spans": [ + { + "bbox": [ + 48, + 434, + 286, + 475 + ], + "type": "text", + "content": "[15] Arthur Gretton, Karsten M Borgwardt, Malte J Rasch, Bernhard Scholkopf, and Alexander Smola. A kernel two-sample test. The Journal of Machine Learning Research, 13(1):723-773, 2012." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 478, + 286, + 520 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 478, + 286, + 520 + ], + "spans": [ + { + "bbox": [ + 48, + 478, + 286, + 520 + ], + "type": "text", + "content": "[16] Dan Hendrycks and Thomas Dietterich. Benchmarking neural network robustness to common corruptions and perturbations. In International Conference on Learning Representations, 2019." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 523, + 286, + 565 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 523, + 286, + 565 + ], + "spans": [ + { + "bbox": [ + 48, + 523, + 286, + 565 + ], + "type": "text", + "content": "[17] Dan Hendrycks and Kevin Gimpel. A baseline for detecting misclassified and out-of-distribution examples in neural networks. In International Conference on Learning Representations, 2016." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 568, + 286, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 568, + 286, + 600 + ], + "spans": [ + { + "bbox": [ + 48, + 568, + 286, + 600 + ], + "type": "text", + "content": "[18] Dan Hendrycks, Mantas Mazeika, and Thomas Dietterich. Deep anomaly detection with outlier exposure. In International Conference on Learning Representations, 2018." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 602, + 286, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 602, + 286, + 644 + ], + "spans": [ + { + "bbox": [ + 48, + 602, + 286, + 644 + ], + "type": "text", + "content": "[19] Rui Huang, Andrew Geng, and Yixuan Li. On the importance of gradients for detecting distributional shifts in the wild. Advances in Neural Information Processing Systems, 34:677-689, 2021." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 647, + 286, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 286, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 286, + 689 + ], + "type": "text", + "content": "[20] Rui Huang and Yixuan Li. Mos: Towards scaling out-of-distribution detection for large semantic space. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8710-8719, 2021." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 692, + 286, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 692, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 692, + 286, + 713 + ], + "type": "text", + "content": "[21] Xiaowei Huang, Daniel Kroening, Wenjie Ruan, James Sharp, Youcheng Sun, Emese Thamo, Min Wu, and Xinping" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 31, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 116 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 116 + ], + "type": "text", + "content": "Yi. A survey of safety and trustworthiness of deep neural networks: Verification, testing, adversarial attack and defence, and interpretability. Computer Science Review, 37:100270, 2020." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 118, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 118, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 308, + 118, + 545, + 150 + ], + "type": "text", + "content": "[22] Conor Igoe, Youngseog Chung, Ian Char, and Jeff Schneider. How useful are gradients for ood detection really? arXiv preprint arXiv:2205.10439, 2022." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 152, + 545, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 152, + 545, + 194 + ], + "spans": [ + { + "bbox": [ + 308, + 152, + 545, + 194 + ], + "type": "text", + "content": "[23] Taewon Jeong and Heeyoung Kim. Ood-maml: Meta-learning for few-shot out-of-distribution detection and classification. Advances in Neural Information Processing Systems, 33:3907-3916, 2020." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 198, + 545, + 250 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 198, + 545, + 250 + ], + "spans": [ + { + "bbox": [ + 308, + 198, + 545, + 250 + ], + "type": "text", + "content": "[24] KJ Joseph, Salman Khan, Fahad Shahbaz Khan, and Vineeth N Balasubramanian. Towards open world object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5830-5840, 2021." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 254, + 545, + 306 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 254, + 545, + 306 + ], + "spans": [ + { + "bbox": [ + 308, + 254, + 545, + 306 + ], + "type": "text", + "content": "[25] KJ Joseph, Jathushan Rajasegaran, Salman Khan, Fahad Shahbaz Khan, and Vineeth N Balasubramanian. Incremental object detection via meta-learning. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(12):9209-9216, 2021." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 309, + 545, + 331 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 309, + 545, + 331 + ], + "spans": [ + { + "bbox": [ + 308, + 309, + 545, + 331 + ], + "type": "text", + "content": "[26] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images. 2009." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 332, + 518, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 332, + 518, + 342 + ], + "spans": [ + { + "bbox": [ + 308, + 332, + 518, + 342 + ], + "type": "text", + "content": "[27] Gustaf Kylberg. Kylberg texture dataset v. 1.0. 2011." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 345, + 545, + 388 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 345, + 545, + 388 + ], + "spans": [ + { + "bbox": [ + 308, + 345, + 545, + 388 + ], + "type": "text", + "content": "[28] Balaji Lakshminarayanan, Alexander Pritzel, and Charles Blundell. Simple and scalable predictive uncertainty estimation using deep ensembles. Advances in neural information processing systems, 30, 2017." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 389, + 545, + 432 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 389, + 545, + 432 + ], + "spans": [ + { + "bbox": [ + 308, + 389, + 545, + 432 + ], + "type": "text", + "content": "[29] Kimin Lee, Kibok Lee, Honglak Lee, and Jinwoo Shin. A simple unified framework for detecting out-of-distribution samples and adversarial attacks. Advances in neural information processing systems, 31, 2018." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 434, + 545, + 477 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 434, + 545, + 477 + ], + "spans": [ + { + "bbox": [ + 308, + 434, + 545, + 477 + ], + "type": "text", + "content": "[30] KIMIN LEE, Kibok Lee, Honglak Lee, and Jinwoo Shin. Training confidence-calibrated classifiers for detecting out-of-distribution samples. In International Conference on Learning Representations, 2018." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 479, + 545, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 479, + 545, + 521 + ], + "spans": [ + { + "bbox": [ + 308, + 479, + 545, + 521 + ], + "type": "text", + "content": "[31] Yi Li and Nuno Vasconcelos. Background data resampling for outlier-aware classification. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13218-13227, 2020." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 524, + 545, + 566 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 524, + 545, + 566 + ], + "spans": [ + { + "bbox": [ + 308, + 524, + 545, + 566 + ], + "type": "text", + "content": "[32] Shiyu Liang, Yixuan Li, and R Srikant. Enhancing the reliability of out-of-distribution image detection in neural networks. In International Conference on Learning Representations, 2018." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 569, + 545, + 612 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 569, + 545, + 612 + ], + "spans": [ + { + "bbox": [ + 308, + 569, + 545, + 612 + ], + "type": "text", + "content": "[33] Ziqian Lin, Sreya Dutta Roy, and Yixuan Li. Mood: Multi-level out-of-distribution detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 15313-15323, 2021." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 614, + 545, + 656 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 614, + 545, + 656 + ], + "spans": [ + { + "bbox": [ + 308, + 614, + 545, + 656 + ], + "type": "text", + "content": "[34] Weitang Liu, Xiaoyun Wang, John Owens, and Yixuan Li. Energy-based out-of-distribution detection. Advances in neural information processing systems, 33:21464-21475, 2020." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 308, + 659, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 659, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 659, + 545, + 712 + ], + "type": "text", + "content": "[35] Ziwei Liu, Zhongqi Miao, Xingang Pan, Xiaohang Zhan, Dahua Lin, Stella X Yu, and Boqing Gong. Open compound domain adaptation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 12406-12415, 2020." + } + ] + } + ], + "index": 30 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 318, + 757 + ], + "type": "text", + "content": "19362" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 117 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 117 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 117 + ], + "type": "text", + "content": "[36] Mingsheng Long, Yue Cao, Jianmin Wang, and Michael Jordan. Learning transferable features with deep adaptation networks. In International Conference on Machine Learning, pages 97-105. PMLR, 2015." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 49, + 118, + 287, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 118, + 287, + 162 + ], + "spans": [ + { + "bbox": [ + 49, + 118, + 287, + 162 + ], + "type": "text", + "content": "[37] Mingsheng Long, Han Zhu, Jianmin Wang, and Michael I Jordan. Deep transfer learning with joint adaptation networks. In International Conference on Machine Learning, pages 2208-2217. PMLR, 2017." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 163, + 287, + 196 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 163, + 287, + 196 + ], + "spans": [ + { + "bbox": [ + 48, + 163, + 287, + 196 + ], + "type": "text", + "content": "[38] Andrey Malinin and Mark Gales. Predictive uncertainty estimation via prior networks. Advances in neural information processing systems, 31, 2018." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 197, + 287, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 197, + 287, + 239 + ], + "spans": [ + { + "bbox": [ + 48, + 197, + 287, + 239 + ], + "type": "text", + "content": "[39] Yifei Ming, Ying Fan, and Yixuan Li. Poem: Out-of-distribution detection with posterior sampling. In International Conference on Machine Learning, pages 15650-15665. PMLR, 2022." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 241, + 287, + 284 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 241, + 287, + 284 + ], + "spans": [ + { + "bbox": [ + 48, + 241, + 287, + 284 + ], + "type": "text", + "content": "[40] Yifei Ming, Yiyou Sun, Ousmane Dia, and Yixuan Li. Cider: Exploiting hyperspherical embeddings for out-of-distribution detection. arXiv preprint arXiv:2203.04450, 2022." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 286, + 287, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 286, + 287, + 330 + ], + "spans": [ + { + "bbox": [ + 48, + 286, + 287, + 330 + ], + "type": "text", + "content": "[41] Yifei Ming, Hang Yin, and Yixuan Li. On the impact of spurious correlation for out-of-distribution detection. In Proceedings of the AAAI Conference on Artificial Intelligence, pages 10051-10059, 2022." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 331, + 287, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 331, + 287, + 374 + ], + "spans": [ + { + "bbox": [ + 48, + 331, + 287, + 374 + ], + "type": "text", + "content": "[42] Sinno Jialin Pan, Ivor W Tsang, James T Kwok, and Qiang Yang. Domain adaptation via transfer component analysis. IEEE Transactions on Neural Networks, 22(2):199-210, 2010." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 376, + 287, + 431 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 376, + 287, + 431 + ], + "spans": [ + { + "bbox": [ + 48, + 376, + 287, + 431 + ], + "type": "text", + "content": "[43] Juan-Manuel Perez-Rua, Xiatian Zhu, Timothy M Hospedales, and Tao Xiang. Incremental few-shot object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 13846-13855, 2020." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 433, + 287, + 475 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 433, + 287, + 475 + ], + "spans": [ + { + "bbox": [ + 48, + 433, + 287, + 475 + ], + "type": "text", + "content": "[44] Shafin Rahman, Salman H Khan, and Fatih Porikli. Zero-shot object detection: Joint recognition and localization of novel concepts. International Journal of Computer Vision, 128:2979-2999, 2020." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 477, + 287, + 520 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 477, + 287, + 520 + ], + "spans": [ + { + "bbox": [ + 48, + 477, + 287, + 520 + ], + "type": "text", + "content": "[45] Chandramouli Shama Sastry and Sageev Oore. Detecting out-of-distribution examples with gram matrices. In International Conference on Machine Learning, pages 8491-8501. PMLR, 2020." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 522, + 287, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 522, + 287, + 555 + ], + "spans": [ + { + "bbox": [ + 48, + 522, + 287, + 555 + ], + "type": "text", + "content": "[46] Yiyou Sun, Chuan Guo, and Yixuan Li. React: Out-of-distribution detection with rectified activations. Advances in Neural Information Processing Systems, 34:144-157, 2021." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 556, + 287, + 599 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 556, + 287, + 599 + ], + "spans": [ + { + "bbox": [ + 48, + 556, + 287, + 599 + ], + "type": "text", + "content": "[47] Yiyou Sun, Yifei Ming, Xiaojin Zhu, and Yixuan Li. Out-of-distribution detection with deep nearest neighbors. In International Conference on Machine Learning, pages 20827-20840. PMLR, 2022." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 601, + 287, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 601, + 287, + 644 + ], + "spans": [ + { + "bbox": [ + 48, + 601, + 287, + 644 + ], + "type": "text", + "content": "[48] Jihoon Tack, Sangwoo Mo, Jongheon Jeong, and Jinwoo Shin. Csi: Novelty detection via contrastive learning on distributionally shifted instances. Advances in neural information processing systems, 33:11839-11852, 2020." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 647, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 287, + 689 + ], + "type": "text", + "content": "[49] Antonio Torralba, Rob Fergus, and William T Freeman. 80 million tiny images: A large data set for nonparametric object and scene recognition. IEEE Transactions on pattern analysis and machine intelligence, 30(11):1958-1970, 2008." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "text", + "content": "[50] Joost Van Amersfoort, Lewis Smith, Yee Whye Teh, and Yarin Gal. Uncertainty estimation using a single deep de" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "text", + "content": "terministic neural network. In International Conference on Machine Learning, pages 9690-9700. PMLR, 2020." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 96, + 545, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 96, + 545, + 140 + ], + "spans": [ + { + "bbox": [ + 308, + 96, + 545, + 140 + ], + "type": "text", + "content": "[51] Sachin Vernekar, Ashish Gaurav, Vahdat Abdelzad, Taylor Denouden, Rick Salay, and Krzysztof Czarnecki. Out-of-distribution detection in classifiers via generation. arXiv preprint arXiv:1910.04241, 2019." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 141, + 545, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 141, + 545, + 173 + ], + "spans": [ + { + "bbox": [ + 308, + 141, + 545, + 173 + ], + "type": "text", + "content": "[52] Ricardo Vilalta and Youssef Drissi. A perspective view and survey of meta-learning. Artificial intelligence review, 18:77-95, 2002." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 175, + 545, + 208 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 175, + 545, + 208 + ], + "spans": [ + { + "bbox": [ + 308, + 175, + 545, + 208 + ], + "type": "text", + "content": "[53] Hao Wang, Hao He, and Dina Katabi. Continuously indexed domain adaptation. In Proceedings of the 37th International Conference on Machine Learning, pages 9898-9907, 2020." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 209, + 545, + 253 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 209, + 545, + 253 + ], + "spans": [ + { + "bbox": [ + 308, + 209, + 545, + 253 + ], + "type": "text", + "content": "[54] Haoqi Wang, Zhizhong Li, Litong Feng, and Wayne Zhang. Vim: Out-of-distribution with virtual-logit matching. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4921-4930, 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 254, + 545, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 254, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 308, + 254, + 545, + 308 + ], + "type": "text", + "content": "[55] Haotao Wang, Aston Zhang, Yi Zhu, Shuai Zheng, Mu Li, Alex J Smola, and Zhangyang Wang. Partial and asymmetric contrastive learning for out-of-distribution detection in long-tailed recognition. In International Conference on Machine Learning, pages 23446-23458. PMLR, 2022." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 310, + 545, + 354 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 310, + 545, + 354 + ], + "spans": [ + { + "bbox": [ + 308, + 310, + 545, + 354 + ], + "type": "text", + "content": "[56] Qin Wang, Olga Fink, Luc Van Gool, and Dengxin Dai. Continual test-time domain adaptation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7201-7211, 2022." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 355, + 545, + 399 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 355, + 545, + 399 + ], + "spans": [ + { + "bbox": [ + 308, + 355, + 545, + 399 + ], + "type": "text", + "content": "[57] Qizhou Wang, Feng Liu, Yonggang Zhang, Jing Zhang, Chen Gong, Tongliang Liu, and Bo Han. Watermarking for out-of-distribution detection. In Advances in Neural Information Processing Systems, 2022." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 400, + 545, + 454 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 400, + 545, + 454 + ], + "spans": [ + { + "bbox": [ + 308, + 400, + 545, + 454 + ], + "type": "text", + "content": "[58] Qizhou Wang, Junjie Ye, Feng Liu, Quanyu Dai, Marcus Kalander, Tongliang Liu, Jianye Hao, and Bo Han. Out-of-distribution detection with implicit outlier transformation. In International Conference on Learning Representations. OpenReview.net, 2023." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 456, + 545, + 500 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 456, + 545, + 500 + ], + "spans": [ + { + "bbox": [ + 308, + 456, + 545, + 500 + ], + "type": "text", + "content": "[59] Zitai Wang, Qianqian Xu, Zhiyong Yang, Yuan He, Xiaochun Cao, and Qingming Huang. Openauc: Towards auc-oriented open-set recognition. Advances in Neural Information Processing Systems, 35:25033-25045, 2022." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 502, + 545, + 545 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 502, + 545, + 545 + ], + "spans": [ + { + "bbox": [ + 308, + 502, + 545, + 545 + ], + "type": "text", + "content": "[60] Hongxin Wei, Renchunzi Xie, Hao Cheng, Lei Feng, Bo An, and Yixuan Li. Mitigating neural network overconfidence with logit normalization. In International Conference on Machine Learning, pages 23631-23644. PMLR, 2022." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 546, + 545, + 601 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 546, + 545, + 601 + ], + "spans": [ + { + "bbox": [ + 308, + 546, + 545, + 601 + ], + "type": "text", + "content": "[61] Jianxiong Xiao, James Hays, Krista A Ehinger, Aude Oliva, and Antonio Torralba. Sun database: Large-scale scene recognition from abbey to zoo. In 2010 IEEE computer society Conference on Computer Vision and Pattern Recognition, pages 3485-3492. IEEE, 2010." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 602, + 545, + 657 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 602, + 545, + 657 + ], + "spans": [ + { + "bbox": [ + 308, + 602, + 545, + 657 + ], + "type": "text", + "content": "[62] Jingkang Yang, Haoqi Wang, Litong Feng, Xiaopeng Yan, Huabin Zheng, Wayne Zhang, and Ziwei Liu. Semantically coherent out-of-distribution detection. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 8301-8309, 2021." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 658, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 658, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 658, + 545, + 713 + ], + "type": "text", + "content": "[63] Jingkang Yang, Pengyun Wang, Dejian Zou, Zitang Zhou, Kunyuan Ding, Wenxuan Peng, Haoqi Wang, Guangyao Chen, Bo Li, Yiyou Sun, et al. Openood: Benchmarking generalized out-of-distribution detection. Advances in Neural Information Processing Systems, 35:32598-32611, 2022." + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "19363" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 229 + ], + "type": "list", + "angle": 0, + "index": 4, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "type": "text", + "content": "[64] Jingkang Yang, Kaiyang Zhou, Yixuan Li, and Ziwei Liu. Generalized out-of-distribution detection: A survey. arXiv preprint arXiv:2110.11334, 2021." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 287, + 138 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 287, + 138 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 287, + 138 + ], + "type": "text", + "content": "[65] Jingkang Yang, Kaiyang Zhou, and Ziwei Liu. Full-spectrum out-of-distribution detection. arXiv preprint arXiv:2204.05306, 2022." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 141, + 287, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 141, + 287, + 184 + ], + "spans": [ + { + "bbox": [ + 48, + 141, + 287, + 184 + ], + "type": "text", + "content": "[66] Fisher Yu, Ari Seff, Yinda Zhang, Shuran Song, Thomas Funkhouser, and Jianxiong Xiao. Lsun: Construction of a large-scale image dataset using deep learning with humans in the loop. arXiv preprint arXiv:1506.03365, 2015." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 186, + 287, + 229 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 186, + 287, + 229 + ], + "spans": [ + { + "bbox": [ + 48, + 186, + 287, + 229 + ], + "type": "text", + "content": "[67] Li Zhong, Zhen Fang, Feng Liu, Bo Yuan, Guangquan Zhang, and Jie Lu. Bridging the theoretical bound and deep algorithms for open set domain adaptation. IEEE Transactions on Neural Networks and Learning Systems, 2021." + } + ] + } + ], + "index": 3 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 317, + 757 + ], + "type": "text", + "content": "19364" + } + ] + } + ], + "index": 5 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 11 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/ab81a251-c4da-4048-9092-c84f97030f0f_content_list.json b/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/ab81a251-c4da-4048-9092-c84f97030f0f_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..d21d4bf2d31f87b90853cfd2c0fbcbee59190833 --- /dev/null +++ b/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/ab81a251-c4da-4048-9092-c84f97030f0f_content_list.json @@ -0,0 +1,1859 @@ +[ + { + "type": "text", + "text": "Meta-ZSDETR: Zero-shot DETR with Meta-learning", + "text_level": 1, + "bbox": [ + 215, + 130, + 756, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Lu Zhang1 Chenbo Zhang1 Jiajia Zhao2 Jihong Guan3 Shuigeng Zhou1*", + "bbox": [ + 163, + 179, + 810, + 198 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{1}$ Shanghai Key Lab of Intelligent Information Processing, and School of Computer Science, Fudan University, China", + "bbox": [ + 200, + 198, + 769, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{2}$ Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory, China", + "bbox": [ + 253, + 233, + 715, + 268 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{3}$ Department of Computer Science & Technology, Tongji University, China", + "bbox": [ + 187, + 268, + 781, + 287 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{1_zhang19,sgzhou}@fudan.edu.cn,cbzhang21@m.fudan.edu.cn", + "bbox": [ + 230, + 289, + 730, + 304 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "zhaojiajial982@gmail.com, jhguan@tongji.edu.cn", + "bbox": [ + 279, + 306, + 689, + 321 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 356, + 313, + 372 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Zero-shot object detection aims to localize and recognize objects of unseen classes. Most of existing works face two problems: the low recall of RPN in unseen classes and the confusion of unseen classes with background. In this paper, we present the first method that combines DETR and meta-learning to perform zero-shot object detection, named Meta-ZSDETR, where model training is formalized as an individual episode based meta-learning task. Different from Faster R-CNN based methods that firstly generate class-agnostic proposals, and then classify them with visual-semantic alignment module, Meta-ZSDETR directly predict class-specific boxes with class-specific queries and further filter them with the predicted accuracy from classification head. The model is optimized with meta-contrastive learning, which contains a regression head to generate the coordinates of class-specific boxes, a classification head to predict the accuracy of generated boxes, and a contrastive head that utilizes the proposed contrastive-reconstruction loss to further separate different classes in visual space. We conduct extensive experiments on two benchmark datasets MS COCO and PASCAL VOC. Experimental results show that our method outperforms the existing ZSD methods by a large margin.", + "bbox": [ + 75, + 388, + 473, + 737 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 762, + 209, + 779 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Object detection [34] is one of the most fundamental tasks in computer vision. Most existing object detection methods require huge amounts of annotated training data, which is expensive and time-consuming to acquire. Meanwhile, in reality novel categories constantly emerge, and there is seriously lack or even nonexistent of visual data of", + "bbox": [ + 75, + 787, + 470, + 878 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/ccbc76cd1200013161c58b7b3c7df57dd1e2ae33624a33d52aee5575bfb2bd69.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 500, + 357, + 893, + 428 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/aafd1f74639b77112c331511209b22ff7d4d38d1cb4c2f1dcf971d11041e4343.jpg", + "image_caption": [ + "Figure 1. Zero-shot object detection: Faster R-CNN based methods vs. Meta-ZSDETR. (a): Faster R-CNN based methods firstly generate class-agnostic proposals, and then classify them with different visual-semantic alignment modules. (b): Meta-ZSDETR directly predict class-specific boxes with class-specific queries and further filter them with classification head." + ], + "image_footnote": [], + "bbox": [ + 500, + 430, + 893, + 503 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "those novel categories for model training, such as endangered species in the wild. The above issues motivate the investigation of zero-shot object detection, which aims to localize and recognize objects of unseen classes.", + "bbox": [ + 496, + 626, + 892, + 686 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "A mainstream framework of the existing works that are based on Faster R-CNN, is illustrated in Fig. 1(a), where the RPN remains unchanged and the RoI classification head is replaced with different visual-semantic alignment modules, such as mapping to the same embedding space to calculate similarity between proposals and semantic vectors [2, 40, 41, 32, 44, 12, 25, 18, 7], synthesizing visual features from semantic vectors [17, 14, 42, 47, 27] etc.", + "bbox": [ + 496, + 688, + 893, + 808 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "However, we observe that the existing methods are suboptimal, due to their obvious inherent shortcomings: i) The proposals from RPN are often not reliable enough to cover all unseen classes objects in an image because of lacking training data, which has also been identified by a recent study [19]. ii) The confusion between background and un", + "bbox": [ + 496, + 810, + 893, + 900 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "* correspondence author", + "bbox": [ + 94, + 887, + 223, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "6845", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "seen classes is an intractable problem. Although many previous works have tried to tackle it [46, 14, 2], the results are still unsatisfactory.", + "bbox": [ + 76, + 90, + 468, + 136 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Recently, object detection frameworks based on the Transformer have gained widespread popularity, such as DETR [5], Deformable DETR [48], etc. Such architectures are RPN-free and background-free, i.e., they do not involve RPN and background class, which are naturally conducive to building zero-shot object detection methods. However, how to build a ZSD method based on DETR detectors poses new challenges. An intuitive idea is to replace DETR's classification head with a zero-shot classifier based on cosine similarity [43]. However, such a method simply treats DETR as a large RPN for proposals generation, the overall framework is essentially the same as previous works.", + "bbox": [ + 75, + 138, + 468, + 319 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this paper, we present the first method that fully explores DETR detectors and meta-learning to perform zero-shot object detection, named Meta-ZSDETR, which can solve the two problems mentioned above that have plagued the field of ZSD for many years, and achieves the state-of-the-art performance. The comparison of Meta-ZSDETR with previous methods is shown in Fig. 1. Different from the previous works that firstly generate class-agnostic proposals and then classify them with visual-semantic alignment module, our method utilizes semantic vectors to guide both proposal generation and classification, which greatly improves the recall of unseen classes. Meanwhile, there is no background class in DETR detectors, which means the confusion between background and unseen classes is no more existent.", + "bbox": [ + 75, + 323, + 468, + 547 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In order to detect unseen classes, we formalize the training process as an individual episode based meta-learning task. In each episode, we randomly sample an image $I$ and a set of classes $C_{\\pi}$ , which contains the positive classes that appear in $I$ and negative classes that do not appear. The meta-learning task is to make the model learn to detect all positive classes of $C_{\\pi}$ on image $I$ . Through the meta-learning task, the training and testing can be unified, i.e., in the model testing, we need only to employ the unseen classes as the set $C_{\\pi}$ . To enable the model to detect an arbitrary class set, we firstly fuse each object query with a projected semantic vector from the class set $C_{\\pi}$ , which transfers the query from class-agnostic to class-specific. Then, the decoder takes the class-specific query as input and predicts the locations of class-specific boxes, together with the probabilities that the boxes belong to the fused class. To achieve the above goal, we propose meta-contrastive learning, where all predictions are split into three different types and different combinations of them are chosen to optimize three different heads, i.e., the regression head to generate the locations of class-specific boxes, the classification head to predict the accuracy of generated boxes, and the contrastive head to separate different classes in visual space for performance improving", + "bbox": [ + 75, + 553, + 468, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "with a contrastive-reconstruction loss. The bipartite matching and loss calculation are performed in a class-by-class manner, and the final loss is averaged over all classes in the sampled class set $\\mathcal{C}_{\\pi}$ .", + "bbox": [ + 498, + 90, + 890, + 150 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In summary, our major contributions are as follows:", + "bbox": [ + 517, + 152, + 861, + 166 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We present the first method that explores DETR and meta-learning to perform zero-shot object detection, which formalizes the training as an individual episode based meta-learning task and ingeniously tackles the two problems that plague ZSD for years.", + "- We propose to train the decoder to directly predict class-specific boxes with class-specific queries as input, under the supervision of our meta-contrastive learning that contains three different heads.", + "- We conduct extensive experiments on two benchmark datasets MSCOCO and PASCAL VOC to evaluate the proposed method Meta-ZSDETR. Experimental results show that our method outperforms the existing ZSD methods." + ], + "bbox": [ + 517, + 176, + 890, + 409 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related work", + "text_level": 1, + "bbox": [ + 500, + 425, + 637, + 441 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Zero-shot learning", + "text_level": 1, + "bbox": [ + 500, + 450, + 679, + 465 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Zero-shot learning (ZSL) aims to classify images of unseen classes that do not appear during training. There are two main streams in ZSL: embedding based methods and generative based methods. The key idea of embedding based methods is to learn an embedding function that maps the semantic vectors and visual features into the same embedding space, where the visual features and semantic vectors can be compared directly [1, 4, 10, 21, 37]. Generative based methods aim to synthesize unseen visual features with variational autoencoder [20] and generative adversarial networks [39], which convert the ZSL into a fully supervised way [6, 13, 36, 38].", + "bbox": [ + 496, + 474, + 890, + 655 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.2. Zero-shot object detection", + "text_level": 1, + "bbox": [ + 500, + 666, + 736, + 681 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Zero-shot object detection (ZSD) has received a great deal of research interest in recent years. Most of ZSD methods are built on Faster R-CNN [11],YOLO [33] and RetinaNet [23]. The process of these methods can be summarized as: generating class-agnostic proposals and classifying proposals into seen/unseen and background classes. The main difference of these methods is that different visual semantic alignment methods are used to complete the classification of proposals. These methods can be divided into two categories: mapping the semantic vectors and visual features to the same embedding space to calculate similarity [2, 40, 41, 32, 44, 12, 25, 18, 7] and synthesizing visual features from semantic vectors [17, 14, 42, 47, 27]. Although previous works have paid great efforts, there are", + "bbox": [ + 496, + 688, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "6846", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "some problems that still have no satisfactory solution, such as the low recall of class-agnostic RPN for unseen classes and the confusion between background and unseen classes. These problems may be caused by the incompatibility of ZSD task and proposals-based architecture such as Faster R-CNN.", + "bbox": [ + 75, + 90, + 468, + 180 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Different from previous works, Meta-ZSDETR is the first work built on Deformable DETR with meta-learning, where the semantic vectors are guided for class-specific boxes generation, instead of class-agnostic proposals in previous works, resulting in a higher unseen recall and precision. Meanwhile, since there is no background class in DETR detectors, the confusion between background and unseen classes is non-existent.", + "bbox": [ + 75, + 181, + 470, + 303 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Method", + "text_level": 1, + "bbox": [ + 76, + 316, + 166, + 330 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Problem definition", + "text_level": 1, + "bbox": [ + 76, + 340, + 256, + 354 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Zero-shot object detection (ZSD) aims to detect objects of unseen classes with model trained on the seen classes. Formally, the class space $\\mathcal{C}$ in ZSD is divided into seen classes $\\mathcal{C}^s$ and unseen classes $\\mathcal{C}^u$ , where $\\mathcal{C} = \\mathcal{C}^s \\cup \\mathcal{C}^u$ and $\\mathcal{C}^s \\cap \\mathcal{C}^u = \\emptyset$ . The training set contains objects of seen classes, where each image $I$ is provided with ground-truth class labels and bounding boxes coordinates. While the test set may contain only unseen objects (ZSD setting) or both seen and unseen classes (GZSD setting). During the training and testing, the semantic vectors $\\mathcal{W} = \\{\\mathcal{W}^s, \\mathcal{W}^u\\}$ is provided for both seen and unseen classes.", + "bbox": [ + 75, + 364, + 468, + 530 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Revisit standard DETR in object detection", + "text_level": 1, + "bbox": [ + 76, + 539, + 439, + 556 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To begin with, we review the pipeline of a standard DETR in generic object detection, which contains the following steps: set prediction, optimal bipartite matching and loss calculation.", + "bbox": [ + 75, + 563, + 468, + 623 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2.1 Set prediction", + "text_level": 1, + "bbox": [ + 76, + 642, + 228, + 657 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "For an image $I$ , the global representation $x_{I}$ is extracted by the backbone $f_{\\phi}$ and Transformer encoder $g_{\\psi}$ successively, which can be expressed as:", + "bbox": [ + 75, + 665, + 468, + 710 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nx _ {I} = g _ {\\psi} \\left(f _ {\\phi} (I)\\right) \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 215, + 723, + 468, + 739 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Then, the decoder $g_{\\theta}$ infers $N$ object predictions $\\hat{\\mathcal{V}}$ , where $N$ is determined by the number of object queries $\\mathcal{Q}$ that serve as learnable positional embedding:", + "bbox": [ + 75, + 752, + 468, + 799 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {\\mathcal {Y}} = g _ {\\theta} \\left(x _ {I}, \\mathcal {Q}\\right) \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 218, + 809, + 468, + 825 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\hat{\\mathcal{V}} = \\{(\\hat{c}_i,\\hat{b}_i)\\}_{i = 1}^N$ and $\\mathcal{Q} = \\{q_i\\}_{i = 1}^N$ . For each object query $q_{i}$ , the decoder $g_{\\theta}$ will output a prediction box, which contains two parts: the predicted class $\\hat{c}_i$ and predicted box location $\\hat{b}_i$ .", + "bbox": [ + 75, + 838, + 468, + 901 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2.2 Optimal bipartite matching", + "text_level": 1, + "bbox": [ + 500, + 90, + 746, + 106 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The optimal bipartite matching is to find the minimal-cost matching between the predictions $\\hat{\\mathcal{Y}} = \\{(\\hat{c}_i,\\hat{b}_i)\\}_{i = 1}^N$ and ground-truth boxes $\\mathcal{V} = \\{(c_i,b_i)\\}_{i = 1}^N$ (padded with no object $\\varnothing$ ). Therefore, we search for a permutation of $N$ elements $\\sigma \\in \\mathfrak{S}_N$ with lowest cost:", + "bbox": [ + 498, + 114, + 890, + 189 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {\\sigma} = \\underset {\\sigma \\in \\mathfrak {S} _ {N}} {\\arg \\min } \\sum_ {i = 1} ^ {N} \\left[ \\mathcal {L} _ {c l s} \\left(c _ {i}, \\hat {c} _ {\\sigma_ {i}}\\right) + \\mathcal {L} _ {l o c} \\left(b _ {i}, \\hat {b} _ {\\sigma_ {i}}\\right) \\right] \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 526, + 199, + 890, + 239 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\mathcal{L}_{cls}(c_i,\\hat{c}_{\\sigma_i})$ and $\\mathcal{L}_{loc}(b_i,\\hat{b}_{\\sigma_i})$ are matching cost for class prediction and box location with index $\\sigma_{i}$ , respectively. Bipartite matching produces one-to-one assignments, where each prediction $(\\hat{c}_i,\\hat{b}_i)$ is assigned to either a ground-truth box $(c_{i},b_{i})$ or $\\varnothing$ (no object). The permutation for lowest cost is calculated with Hungarian algorithm.", + "bbox": [ + 498, + 252, + 890, + 344 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2.3 Hungarian loss", + "text_level": 1, + "bbox": [ + 500, + 361, + 660, + 376 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Hungarian loss is a widely used loss function in DETR, which takes the following form:", + "bbox": [ + 498, + 385, + 890, + 415 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {H u g} = \\sum_ {i = 1} ^ {N} \\left[ \\mathcal {L} _ {c l s} \\left(c _ {i}, \\hat {c} _ {\\hat {\\sigma} _ {i}}\\right) + \\mathbb {1} _ {\\{c _ {i} \\neq \\emptyset \\}} \\mathcal {L} _ {l o c} \\left(b _ {i}, \\hat {b} _ {\\hat {\\sigma} _ {i}}\\right) \\right] \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 513, + 425, + 890, + 467 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\hat{\\sigma}$ is the optimal assignment computed in Eq.(3). $\\mathcal{L}_{cls}$ is the loss for classification, which usually takes the form of focal loss [23] or cross-entropy loss. $\\mathcal{L}_{loc}$ is the location loss and usually contains $l_{1}$ loss and GIoU loss [35].", + "bbox": [ + 498, + 474, + 890, + 536 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Challenge: Since the standard DETR can only locate the boxes and predict the classes of objects in training set, it is unable to detect unseen classes. In this paper, we utilize the meta-learning to make the model learn to detect objects according to the inputted semantic vectors, so that the model has the ability to detect objects of any category, as long as the semantic vector of the corresponding category is input.", + "bbox": [ + 498, + 537, + 890, + 642 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.3. Framework", + "text_level": 1, + "bbox": [ + 500, + 650, + 625, + 665 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We present the framework of Meta-ZSDETR in Fig. 2, which is based on Deformable DETR. Meta-ZSDETR follows the paradigm of meta-learning. The training is performed by episode based meta-learning task. In each episode, we randomly sample an image $I$ and a class set $\\mathcal{C}_{\\pi}$ . The meta-learning task of each episode is to make the model learn to detect all appeared classes in $\\mathcal{C}_{\\pi}$ on image $I$ . Specifically, the image feature is firstly extracted by backbone and Transformer encoder as in Eq.(1). In order for the decoder to detect categories in $\\mathcal{C}_{\\pi}$ , we add the projected semantic vectors of classes $\\mathcal{C}_{\\pi}$ to the object queries, making the queries class-specific. Then, the decoder takes the queries as input and predicts the class-specific boxes directly. To achieve this, the model is optimized with meta-contrastive learning, which contains a regression head to generate the", + "bbox": [ + 498, + 674, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "6847", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/221136650e966e25028c4e141636cada1bb0207402e20d8f25021fa0d3ab391f.jpg", + "image_caption": [ + "Figure 2. The framework of Meta-ZSDETR. In each episode, a class set $\\mathcal{C}_{\\pi}$ and an image $I$ are sampled. The meta-learning task is to make the model learn to detect all appeared classes in $\\mathcal{C}_{\\pi}$ . Firstly, the image feature $x_{I}$ is extracted with backbone and encoder. Then, the projected semantic vectors are added to object queries, making them class-specific. Finally, the decoder $g_{\\theta}$ will takes the queries as input and directly predict class-specific boxes. To achieve this, we train our model with proposed meta-contrastive learning." + ], + "image_footnote": [], + "bbox": [ + 117, + 88, + 851, + 244 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "coordinates of class-specific boxes, a classification to predict the accuracy of generated boxes and a contrastive head that utilize the proposed contrastive-reconstruction loss to further separate different classes in visual space.", + "bbox": [ + 75, + 339, + 468, + 401 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.4. Meta-ZSDETR with class-specific queries", + "text_level": 1, + "bbox": [ + 76, + 411, + 431, + 428 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To enable the model to detect any unseen class, we fuse the object queries with class semantic information, and make the model learn to predict the bounding boxes for the fused classes. Such a process is carried out in each meta-learning task.", + "bbox": [ + 75, + 436, + 468, + 511 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Specifically, in each episode, we randomly sample a class set $\\mathcal{C}_{\\pi}$ and an image $I$ , where the $\\mathcal{C}_{\\pi}$ satisfies $\\mathcal{C}_{\\pi} \\subseteq \\mathcal{C}^s$ and each element is unique. Meanwhile, $\\mathcal{C}_{\\pi} = \\mathcal{C}_{\\pi}^{+} \\cup \\mathcal{C}_{\\pi}^{-}$ , where $\\mathcal{C}_{\\pi}^{+}$ is the positive classes that appeared in image $I$ and $\\mathcal{C}_{\\pi}^{-}$ is the randomly sampled negative classes that do not appear in $I$ for contrast. Meanwhile, we denote the size of $\\mathcal{C}_{\\pi}$ as $L(\\mathcal{C}_{\\pi})$ , where $L(\\cdot)$ is the operation that calculates size. The positive rate $\\frac{L(\\mathcal{C}_{\\pi}^{+})}{L(\\mathcal{C}_{\\pi})}$ is set to $\\lambda_{\\pi}$ , which is a hyperparameter.", + "bbox": [ + 75, + 512, + 468, + 651 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Then, the corresponding semantic vectors $\\mathcal{W}_{\\pi}$ of class set $\\mathcal{C}_{\\pi}$ are projected from semantic space to the visual space with a linear layer $h_{\\mathcal{W}}$ :", + "bbox": [ + 75, + 652, + 468, + 698 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\widetilde {\\mathcal {W} _ {\\pi}} = h _ {\\mathcal {W}} \\left(\\mathcal {W} _ {\\pi}\\right) \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 215, + 712, + 468, + 732 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\widetilde{\\mathcal{W}_{\\pi}}$ is the projected semantic vectors of class set $\\mathcal{C}_{\\pi}$ . Since $L(\\widetilde{\\mathcal{W}_{\\pi}})\\ll N$ , i.e. the number of semantic vectors is smaller than the number of object queries $\\mathcal{Q}$ , we expand $\\widetilde{\\mathcal{W}_{\\pi}}$ by duplicating each element in $\\widetilde{\\mathcal{W}_{\\pi}}$ for $T$ times, which satisfies $L(\\widetilde{\\mathcal{W}_{\\pi}})\\cdot T\\geqslant N$ and $L(\\widetilde{\\mathcal{W}_{\\pi}})\\cdot (T - 1) < N$ . For redundant elements more than $N$ , we drop them.", + "bbox": [ + 75, + 739, + 468, + 837 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Then, the projected semantic vectors $\\widetilde{\\mathcal{W}_{\\pi}}$ is added to object queries $\\mathcal{Q}$ as follows:", + "bbox": [ + 73, + 838, + 468, + 869 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {Q} _ {\\pi} = \\mathcal {Q} \\oplus \\widetilde {\\mathcal {W} _ {\\pi}} \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 218, + 882, + 468, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathcal{Q}_{\\pi} = \\{q_i^\\pi \\}_{i=1}^N$ is the class-specific queries that will be inputted into the Transformer decoder $g_{\\theta}$ with image feature $x_I$ to generate predictions:", + "bbox": [ + 496, + 339, + 890, + 385 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {\\mathcal {Y}} = g _ {\\theta} \\left(x _ {I}, \\mathcal {Q} _ {\\pi}\\right) \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 638, + 396, + 890, + 414 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "$\\hat{\\mathcal{V}} = \\{(\\hat{\\delta}_i,\\hat{b}_i)\\}_{i = 1}^N$ is the set of predictions, where $\\hat{b}_i$ is predicted box location generated with query $q_{i}^{\\pi}$ and $\\hat{\\delta}_i$ is the probability of box $\\hat{b}_i$ belonging to the fused class, i.e. the class of semantic vector that fused to query $q_{i}^{\\pi}$ . Meanwhile, different from the standard DETR that the classification head determines the class of predicted boxes, the class of predicted box $\\hat{b}_i$ in Meta-ZSDETR is class-specific and is determined by the class of corresponding query and $\\hat{\\delta}_i$ only has one dimension to represent the probability of $\\hat{b}_i$ belongs to the fused class.", + "bbox": [ + 496, + 424, + 892, + 580 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.5. Meta-contrastive learning", + "text_level": 1, + "bbox": [ + 500, + 590, + 735, + 606 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In order for the regression head of decoder $g_{\\theta}$ to generate more accurate class-specific box coordinate $\\hat{b}_i$ and classification head to have a stronger discriminative ability of further judging the location accuracy of generated $\\hat{b}_i$ , we propose the meta-contrastive learning to train the heads of decoder $g_{\\theta}$ , i.e. a regression head to generate class-specific boxes, a classification head to filter inaccurate boxes, and moreover a contrastive head to further separate different classes in visual space, which will improve the performance of both seen classes and unseen classes.", + "bbox": [ + 496, + 613, + 890, + 763 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Meta-contrastive learning performs the matching and optimization in a class-by-class manner. As shown in Fig. 3, for each class $c_{j}^{\\pi} \\in \\mathcal{C}_{\\pi}$ , the decoder takes queries of class $c_{j}^{\\pi}$ as input, and the predictions are split into three types: 1) The positive predictions that are assigned to GT box of class $c_{j}^{\\pi}$ by class-specific bipartite matching. 2) The negative predictions that are assigned to any other classes than $c_{j}^{\\pi}$ . 3) The negative predictions that belong to background.", + "bbox": [ + 496, + 763, + 890, + 886 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Then, we takes different combinations of three types", + "bbox": [ + 517, + 886, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "6848", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/177140d1fb979f02742c666f439bf6db8b569ae17dba4a05c901c14149c88706.jpg", + "image_caption": [ + "Figure 3. All predictions of class $c_{j}^{\\pi}$ are split into three different types and different combinations of them are utilized to train three different heads." + ], + "image_footnote": [], + "bbox": [ + 78, + 88, + 472, + 250 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "of predictions to train three heads: a) For the classification head, we take all predictions for the training and give them corresponding positive/negative class-specific targets for class $c_{j}^{\\pi}$ . b) For the regression head, since the regression head aims to generate class-specific boxes of class $c_{j}^{\\pi}$ , we only utilize the positive predictions for optimization. c) For the contrastive head, since our intention is to separate different classes in visual space, we only use positive predictions of class $c_{j}^{\\pi}$ and negative predictions of other classes for contrastive-reconstruction loss.", + "bbox": [ + 75, + 327, + 472, + 478 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.5.1 Class-specific bipartite matching", + "text_level": 1, + "bbox": [ + 76, + 497, + 359, + 513 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Our meta-contrastive learning performs the matching in a class-by-class manner. For class $c_{j}^{\\pi} \\in \\mathcal{C}_{\\pi}$ , the predictions generated by queries of class $c_{j}^{\\pi}$ are selected for bipartite matching, which is denoted as $\\hat{\\mathcal{Y}}_{c_j^\\pi} = \\{(\\hat{\\delta}_{\\tau_i},\\hat{b}_{\\tau_i})\\}_{i = 1}^{T_\\tau}$ where $\\{\\tau_i\\}_{i = 1}^{T_\\tau}$ are the indexes for queries of class $c_{j}^{\\pi}$ in $N$ queries. Since each query is duplicated for $T$ or $T - 1$ times, we denote the length uniformly as $T_{\\tau}$ .", + "bbox": [ + 75, + 521, + 468, + 633 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Then, the ground-truth matching targets are revised for each class $c_{j}^{\\pi}\\in \\mathcal{C}_{\\pi}$ . The class-specific matching labels are denoted as $\\Delta_{c_j^\\pi} = \\{\\delta_i^{c_j^\\pi}\\}_{i = 1}^{T_\\tau}$ (padded with no objects $\\varnothing$ ), which satisfy:", + "bbox": [ + 75, + 635, + 468, + 700 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\delta_ {i} ^ {c _ {j} ^ {\\pi}} = \\left\\{ \\begin{array}{l l} 1, & c _ {i} = c _ {j} ^ {\\pi} \\\\ 0, & c _ {i} \\neq c _ {j} ^ {\\pi} \\end{array} \\right. \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 199, + 712, + 468, + 747 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $c_{i}$ is the origin class label for ground-truth box $b_{i}$ . The revised matching labels are generated according to whether $c_{i}$ is equal to $c_{j}^{\\pi}$ . Then, the matching targets $\\mathcal{Y}_{c_j^\\pi} = \\{(\\delta_i^{c_j^\\pi}, b_i)\\}_{i=1}^{T_\\tau}$ is utilized for bipartite matching of class $c_{j}^{\\pi}$ , where a permutation of $T_{\\tau}$ elements $\\sigma \\in \\mathfrak{S}_{T_{\\tau}}$ with lowest cost is search as:", + "bbox": [ + 76, + 756, + 470, + 852 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {\\sigma} = \\underset {\\sigma \\in \\mathfrak {S} _ {T \\tau}} {\\arg \\min } \\sum_ {i = 1} ^ {T _ {\\tau}} \\left[ \\mathcal {L} _ {c l s} (\\delta_ {i} ^ {e _ {j} ^ {\\pi}}, \\hat {\\delta} _ {\\tau_ {\\sigma_ {i}}}) + \\mathcal {L} _ {l o c} (b _ {i}, \\hat {b} _ {\\tau_ {\\sigma_ {i}}}) \\right] \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 93, + 862, + 468, + 904 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\hat{\\sigma}$ is the optimal assignment between matching targets $\\mathcal{V}_{c_j^\\pi}$ and predictions $\\hat{\\mathcal{V}}_{c_j^\\pi}$ . $\\mathcal{L}_{cls}$ and $\\mathcal{L}_{loc}$ are the same as that in Eq.(3).", + "bbox": [ + 498, + 90, + 890, + 137 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.5.2 Loss function", + "text_level": 1, + "bbox": [ + 500, + 154, + 648, + 167 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Based on $\\hat{\\sigma}$ , predictions in $\\hat{Y}_{c_j^\\pi}$ are split into three types mentioned above, i.e. positive and two types of negative ones, and loss function of class $c_{j}^{\\pi}$ for three heads are calculated as follows:", + "bbox": [ + 496, + 175, + 890, + 233 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {c _ {j} ^ {\\pi}} = \\sum_ {i = 1} ^ {T _ {\\tau}} \\left[ \\mathcal {L} _ {c l s} \\left(\\delta_ {i} ^ {c _ {j} ^ {\\pi}}, \\hat {\\delta} _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) + \\mathbb {1} _ {\\left(c _ {i} = c _ {j} ^ {\\pi}\\right)} \\mathcal {L} _ {l o c} \\left(b _ {i}, \\hat {b} _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) \\right] + \\mathcal {L} _ {c o n t} \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 500, + 237, + 890, + 286 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where the loss $\\mathcal{L}_{c_j^\\pi}$ for class $c_{j}^{\\pi}$ is composed of classification loss $\\mathcal{L}_{cls}$ , regression loss $\\mathcal{L}_{loc}$ and contrastive-reconstruction loss $\\mathcal{L}_{cont}$ .", + "bbox": [ + 496, + 287, + 890, + 332 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Classification loss. $\\mathcal{L}_{cls}$ takes all predictions as input and makes the model learn to distinguish whether a predicted box belongs to $c_{j}^{\\pi}$ . The predicted box has the label $\\delta_{i}^{c_{j}^{\\pi}} = 1$ if and only if it is assigned to a ground-truth box with class label $c_{j}^{\\pi}$ . We implement $\\mathcal{L}_{cls}$ with focal loss [23].", + "bbox": [ + 496, + 332, + 890, + 414 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Regression loss. Since our intention is to generate class-specific boxes, i.e. input decoder with query of class $c_{j}^{\\pi}$ and output box of class $c_{j}^{\\pi}$ , we only select the ground-truth box with class label $c_{j}^{\\pi}$ for optimization, i.e. $\\delta_{i}^{c_{j}^{\\pi}} = 1$ , making the predicted boxes to be closer to GT boxes with class label $c_{j}^{\\pi}$ . The $\\mathcal{L}_{loc}$ is implemented with $l_{1}$ loss and GIoU loss [35].", + "bbox": [ + 496, + 414, + 890, + 511 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Contrastive-reconstruction loss. In ZSD tasks, the original visual space is not well-structured due to the lack of discriminative information, many previous works solved it by introducing a reconstruction loss to guide the distribution of visual features. Here, we combine the reconstruction loss and contrastive loss to bring a higher intra-class compactness and inter-class separability of the visual structure.", + "bbox": [ + 496, + 511, + 890, + 614 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In particular, we project the last hidden features of decoder to the semantic space, where the projected hidden features of positive predictions are constraint to be as close as possible to $\\omega_{j}^{\\pi}$ , which is the semantic vector of class $c_{j}^{\\pi}$ and the negative ones are constraint to be as far as possible to $\\omega_{j}^{\\pi}$ . Formally, we denote the last hidden feature of optimal box $(\\hat{\\delta}_{\\tau_{\\hat{\\sigma}_i}},\\hat{b}_{\\tau_{\\hat{\\sigma}_i}})$ that matched to GT box $(c_i,b_i)$ as $z_{\\tau_{\\hat{\\sigma}_k}}$ and the $\\mathcal{L}_{cont}$ is formulated as:", + "bbox": [ + 496, + 616, + 890, + 739 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {c o n t}} = \\frac {1}{N _ {\\text {p o s}}} \\sum_ {i = 1} ^ {T _ {\\tau}} \\mathbb {1} _ {\\left(c _ {i} = c _ {j} ^ {\\pi}\\right)} \\mathcal {L} _ {\\text {c o n t}} \\left(z _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 563, + 750, + 890, + 792 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {c o n t}} \\left(z _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) = - \\log \\frac {\\exp \\left[ h _ {\\rho} \\left(z _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) \\cdot \\omega_ {j} ^ {\\pi} / \\kappa \\right]}{\\sum_ {k = 1} ^ {T _ {\\tau}} \\mathbb {1} _ {(c _ {k} \\neq \\varnothing)} \\exp \\left[ h _ {\\rho} \\left(z _ {\\tau_ {\\hat {\\sigma} _ {k}}}\\right) \\cdot \\omega_ {j} ^ {\\pi} / \\kappa \\right]} \\tag {12}\n$$\n", + "text_format": "latex", + "bbox": [ + 500, + 801, + 890, + 854 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $h_{\\rho}$ is a linear layer that projects the hidden feature to the semantic space. $N_{pos}$ is the number of positive predictions of class $c_{j}^{\\pi}$ . $\\kappa$ is a temperature hyper-parameter", + "bbox": [ + 496, + 854, + 890, + 902 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "6849", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "as in InfoNCE [28]. The optimization of the above loss function increases the instance-level similarity between projected hidden features of positive predictions with semantic vector $\\omega_{j}^{\\pi}$ and space the negative ones. As a result, visual features of the same class will form a tighter cluster.", + "bbox": [ + 75, + 90, + 468, + 166 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Total loss function. We compute the loss function with Eq.(10) for each class $c_{j}^{\\pi} \\in \\mathcal{C}_{\\pi}$ , separately. For negative classes $\\mathcal{C}_{\\pi}^{-}$ , only classification loss is calculated. Finally, the loss of current episode is averaged over all classes in sampled class set $\\mathcal{C}_{\\pi}$ :", + "bbox": [ + 75, + 167, + 468, + 242 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} = \\frac {1}{L \\left(\\mathcal {C} _ {\\pi}\\right)} \\sum_ {j = 1} ^ {L \\left(\\mathcal {C} _ {\\pi}\\right)} \\mathcal {L} _ {c _ {j} ^ {\\pi}} \\tag {13}\n$$\n", + "text_format": "latex", + "bbox": [ + 197, + 247, + 468, + 292 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $L(\\mathcal{C}_{\\pi})$ is the number of classes in $\\mathcal{C}_{\\pi}$ . We utilize $\\mathcal{L}$ for model optimization.", + "bbox": [ + 75, + 297, + 468, + 328 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 339, + 209, + 356 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Datasets and splits", + "text_level": 1, + "bbox": [ + 76, + 363, + 256, + 380 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Following previous works [40, 17], we takes two benchmark datasets for evaluation: PASCAL VOC 2007+2012 [9] and MS COCO 2014 [24].", + "bbox": [ + 75, + 386, + 468, + 431 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Datasets: PASCAL VOC contains 20 classes of objects for object detection. More specifically, the PASCAL VOC 2,007 is composed of 2,501 training images, 2,510 validation images, and 5,011 test images. The PASCAL VOC 2012 dataset comprises 5,717 training images and 5,823 validation images, without test images released. MS COCO 2014 is a benchmark dataset designed for object detection and semantic segmentation tasks, which contains 82,783 training and 40,504 validation images from 80 categories. For PASCAL VOC and MS COCO, we adopt the Fast-Text [26] to extract the semantic vectors following [14, 17].", + "bbox": [ + 75, + 431, + 468, + 598 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Seen/unseen splits: All splits follow the previous setting [40, 17]. For PASCAL VOC, we use a 16/4 split proposed in [7]. For MS COCO, we follow the same procedures described in [2, 29, 17] to take 2 different splits, i.e. 48/17 and 65/15. For all datasets, the images that contain unseen classes in the training set are removed to guarantee that unseen objects will not be available during training.", + "bbox": [ + 75, + 598, + 468, + 704 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Evaluation protocols", + "text_level": 1, + "bbox": [ + 76, + 710, + 272, + 727 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We adopt the widely-used evaluation protocols proposed in [2, 7]. For PASCAL VOC, mAP with IoU threshold 0.5 is used to evaluate the performance. For MS COCO, mAP and recall@100 with three different IoU threshold (i.e. 0.4, 0.5 and 0.6) are utilized for evaluation. For GZSD setting that contains both seen and unseen classes, the performance is evaluated by Harmonic Mean (HM).", + "bbox": [ + 75, + 734, + 468, + 839 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Implementation details", + "text_level": 1, + "bbox": [ + 76, + 847, + 290, + 863 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We build Meta-ZSDETR on Deformable DETR [48] with ResNet-50 [16] as backbone. The number of queries", + "bbox": [ + 76, + 869, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/5240e18f08495e95b74991a18cf40788e18a8d8e4e7531c146c03ebd1794353c.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodZSDGZSD
SUHM
SAN [31]59.148.037.041.8
HRE [8]54.262.425.536.2
PL [30]62.1---
BLC [45]55.258.222.932.9
SU [15]64.9---
Robust-Syn [17]65.547.149.148.1
ContrastZSD [40]65.763.246.553.6
Meta-ZSDETR70.367.656.361.4
", + "bbox": [ + 504, + 88, + 888, + 262 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/59989c2c44161919d6667a987c9dae207b8f558c6dce89adbe5df85dab404013.jpg", + "table_caption": [ + "Table 1. The results of mAP in PASCAL VOC with IoU=0.5 under ZSD and GZSD settings. Here, \"S\" denotes seen classes, \"U\" denotes unseen classes and \"HM\" denotes harmonic mean." + ], + "table_footnote": [], + "table_body": "
MethodcardogsofatrainmAP
SAN [31]56.285.362.626.457.6
HRE [8]55.082.055.026.054.5
PL [30]63.787.253.244.162.1
BLC [45]43.78660.830.155.2
SU [15]59.692.762.345.264.9
Robust-Syn [17]60.193.059.749.165.5
ContrastZSD [40]65.586.463.147.965.7
Meta-ZSDETR69.092.465.754.170.3
", + "bbox": [ + 501, + 324, + 890, + 477 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2. Class-wise AP and mAP on unseen classes in PASCAL VOC under ZSD setting.", + "bbox": [ + 498, + 486, + 890, + 513 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "$N$ is set to 900. For the sampled class set $\\mathcal{C}_{\\pi}$ , the positive classes consist of the classes that appear in the image and the negative classes is sampled from $\\mathcal{C}^s$ . The positive rate $\\lambda_{\\pi}$ is set to 0.5. The number of Transformer encoder layers and decoder layers is set to 6. The temperature hyperparameter $\\kappa$ in Eq.(12) is set to 0.2. We train our model for total 500,000 iterations with batch size 16, i.e. each iteration contains 16 episodes in parallel. Following Deformable DETR, different coefficients are utilized to weight different loss functions, where 1.0 is used for classification loss, 5.0 is used for $l_1$ loss of regression head, 2.0 is used for GIoU loss of regression head and 1.0 is used for contrastive-reconstruction loss. More details can refer to our code.", + "bbox": [ + 496, + 540, + 890, + 736 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.4. Comparison with existing methods", + "text_level": 1, + "bbox": [ + 498, + 747, + 802, + 763 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.4.1 PASCAL VOC", + "text_level": 1, + "bbox": [ + 500, + 770, + 658, + 784 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We present the results of PASCAL VOC in Tab. 1, where we can see that our method performs best among all existing methods under both ZSD and GZSD settings, and lift the mAP in PASCAL VOC to a higher level.", + "bbox": [ + 496, + 794, + 890, + 854 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Specifically, in ZSD setting, Meta-ZSDETR achieves 70.3 mAP and outperform the second-best model ContrastZSD [40] by a large margin of 4.6 mAP, which is the", + "bbox": [ + 498, + 854, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "6850", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/02c490e7734e88986d7341857c206cceddefd3baa257198bab62e6697ca9cc45.jpg", + "table_caption": [], + "table_footnote": [ + "Table 3. ZSD performance of Recall@100 and mAP with different IoU thresholds on MS COCO dataset." + ], + "table_body": "
MethodSplitRecall@100mAP
IoU=0.4IoU=0.5IoU=0.6IoU=0.5
DSES [3]48/1740.227.213.60.5
TD [22]48/1745.534.318.1-
PL [30]48/17-43.5-10.1
BLC [45]48/1751.348.845.010.6
ZSDTR [43]48/1751.848.544.510.4
Robust-Syn [17]48/1758.153.547.913.4
ContrastZSD [40]48/1756.152.447.212.5
Meta-ZSDETR48/1762.359.854.215.1
PL [30]65/15-37.7-12.4
BLC [45]65/1557.254.751.214.7
SU [15]65/1554.454.047.019.0
ZSDTR [43]65/1563.860.356.513.2
Robust-Syn [17]65/1565.362.355.919.8
ContrastZSD [40]65/1562.359.555.118.6
Meta-ZSDETR65/1569.166.759.022.5
", + "bbox": [ + 76, + 89, + 478, + 375 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "first time to boost the performance of ZSD setting on PASCAL VOC to over $70\\mathrm{mAP}$ .", + "bbox": [ + 75, + 435, + 468, + 464 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "For GZSD setting, our method also achieves SOTAs in all three metrics, i.e. mAP on seen classes, unseen classes and harmonic mean, which brings about 4.4, 9.8 and 7.8 points improvement, respectively. It is worth noting that the improvement of our method on unseen classes in GZSD setting is extremely large, which proves that our method has a strong generalization on unseen classes, and can alleviate the problem that the unseen classes tend to be misclassified into seen classes to a certain extent. We also report class-wise mAP in ZSD setting in Tab. 2, where our method achieves the best performance on 3 classes.", + "bbox": [ + 75, + 465, + 468, + 633 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.4.2 MS COCO", + "text_level": 1, + "bbox": [ + 76, + 650, + 209, + 664 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We perform experiments on MS COCO, where the results of ZSD setting is shown in Tab. 3 and the results of GZSD setting is shown in Tab. 4. We can see that Meta-ZSDETR achieves the best results in all metrics under all settings.", + "bbox": [ + 75, + 672, + 468, + 734 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "For ZSD setting, we can see that mAP of our method in 48/17 and 65/15 splits outperforms the second-best by a margin of 1.7 and $2.7\\mathrm{mAP}$ , respectively, which demonstrates that our method generalizes well to unseen classes. Meanwhile, we can see that Recall@100 decrease as the IoU increases in all methods. Compared with other methods, Meta-ZSDETR has a smaller drop, which is benefit from that our decoder can generate more accurate boxes with class semantic information as input.", + "bbox": [ + 75, + 734, + 468, + 869 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "For GZSD setting, our method achieves SOTAs in both seen and unseen classes. The harmonic means of mAP un", + "bbox": [ + 76, + 869, + 468, + 900 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/7a0fbbed65d9f685bdcf8ab57e00bc19edb1a2830818fc18c244a21a15d935e1.jpg", + "table_caption": [], + "table_footnote": [ + "Table 4. GZSD performance of Recall@100 and mAP with IoU=0.5 on MS COCO dataset." + ], + "table_body": "
MethodSplitRecall@100mAP
SUHMSUHM
PL [30]48/1738.226.331.235.94.17.4
BLC [45]48/1757.646.451.442.14.58.2
ZSDTR [43]48/1774.348.460.548.55.69.5
Robust-Syn [17]48/1759.758.859.242.313.420.4
ContrastZSD [40]48/1765.752.458.345.16.311.1
Meta-ZSDETR48/1774.359.065.848.714.622.5
PL [30]65/1536.437.236.834.112.418.2
BLC [45]65/1556.451.753.936.013.119.2
SU [15]65/1557.753.955.836.919.025.1
ZSDTR [43]65/1569.159.561.140.613.220.2
Robust-Syn [17]65/1558.661.860.237.419.826.0
ContrastZSD [40]65/1562.958.660.740.216.523.4
Meta-ZSDETR65/1571.165.468.145.921.729.5
", + "bbox": [ + 500, + 89, + 901, + 345 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/1add503ae86270c5d60228c566750b01b6fa387feff178884e89f8d317a97066.jpg", + "table_caption": [], + "table_footnote": [ + "Table 5. Ablation study of different combinations of loss functions." + ], + "table_body": "
LocClsContSeenUnseen
✓39.914.5
✓✓44.820.6
✓✓40.615.3
✓✓✓45.921.7
", + "bbox": [ + 557, + 392, + 834, + 484 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "der 48/17 and 65/15 splits are improved from 20.4 to 22.5, and from 26.0 to 29.5, demonstrating the effectiveness and superiority of our method. Meanwhile, the Recall@100 also improves due to the powerful class-specific boxes generation capabilities. We also report the class-wise AP in 65/15 split of MS COCO, which can be found in our supplementary material.", + "bbox": [ + 496, + 534, + 890, + 641 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.5. Ablation study", + "text_level": 1, + "bbox": [ + 500, + 650, + 650, + 666 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We analyze the effects of various components in Meta-ZSDETR. Unless otherwise specified, the experiments are carried out on MS COCO with 65/15 split under GZSD setting and use mAP with IoU=0.5 as metric.", + "bbox": [ + 496, + 672, + 890, + 734 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Effects of different loss functions. Here, we analyze the effects of three loss functions in meta-contrastive learning. We utilize different combinations of regression loss $\\mathcal{L}_{loc}$ , classification loss $\\mathcal{L}_{cls}$ and contrastive-reconstruction loss $\\mathcal{L}_{cont}$ to optimize the model, and show the results in Tab. 5. Since the regression loss is necessary, we keep it for all combinations. For model without classification loss $\\mathcal{L}_{cls}$ , we do not perform the boxes filter and directly use the class-specific boxes predicted from regression head, where the scores are generated randomly. As we can see, if the model is only trained with regression head to gen", + "bbox": [ + 496, + 734, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "6851", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/eec84ac3588a8481c62518ad3d2c0d03d921cafab99e904c1aa762b34c0ab9dd.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Heads\\( \\hat{y}_{pos} \\)\\( \\hat{y}_{other} \\)\\( \\hat{y}_{bg} \\)SeenUnseen
Classification Head✓✓43.717.9
✓✓44.819.0
✓✓✓45.921.7
Regression Head✓45.921.7
✓✓42.116.5
Contrastive Head✓45.121.0
✓✓45.921.7
✓✓✓45.421.3
", + "bbox": [ + 88, + 88, + 459, + 243 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 6. Ablation study on using different combinations of predictions to train three heads.", + "bbox": [ + 76, + 253, + 468, + 280 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "erate class-specific boxes, it can achieve a mAP of 14.5 in unseen classes, which is relatively low, but also surpasses many previous methods. Adding the classification loss will greatly boost the performance of unseen classes to $20.6\\mathrm{mAP}$ , which thanks to the powerful discriminative ability of the classification head that can filter inaccurate boxes. Meanwhile, the contrastive-reconstruction loss can improve the performance with and without the classification head about 1 point. Finally, the combination of three losses achieves the best performance.", + "bbox": [ + 75, + 306, + 468, + 455 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Study for training of different heads. As describe, based on the class-specific bipartite matching for class $c_{j}^{\\pi}$ , all predictions are split into three different types: the positive predictions $\\hat{Y}_{pos}$ assigned to GT boxes of $c_{j}^{\\pi}$ , the negative predictions $\\hat{Y}_{other}$ assigned to other classes and the negative predictions $\\hat{Y}_{bg}$ that belong to background. Here, we study different combinations of them to train three heads and the results are shown in Tab. 6. We can see that: 1) For classification head, since it aims to filter all kinds of negative predictions, using all predictions to train it can achieve the best performance. 2) For regression head, if we train it with GT boxes of all classes, i.e. using $\\hat{Y}_{pos}$ and $\\hat{Y}_{other}$ , the regression head will degenerate into a class-agnostic RPN, which will greatly reduce the recall of unseen classes, thus lead to a lower mAP. 3) For contrastive head, on one hand, if we only use $\\hat{Y}_{pos}$ for training, it will degenerate into a reconstruction loss, which has been widely used in previous works and it will bring a 0.4 mAP improvement in unseen classes compared with the version without it. On the other hand, compared with using all predictions, removing background predictions will make the contrastive head focus on distinguishing $\\hat{Y}_{other}$ and inputed semantic vectors of class $c_{j}^{\\pi}$ , thus brings more improvement.", + "bbox": [ + 75, + 458, + 470, + 808 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Visualization for contrastive-reconstruction loss. Here, we study the influence of contrastive-reconstruction loss on visual space by visualizing the distribution of hidden features with t-SNE. We visualize the last hidden features of decoder in unseen classes of PASCAL VOC. The result is shown in Fig. 4. As we can see, our contrastive", + "bbox": [ + 75, + 810, + 468, + 901 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/82eafe7a1ae372f9a1ec5a0c2466cc28ad5ee6521d163acf4375d75c75fd4203.jpg", + "image_caption": [ + "Figure 4. The t-SNE visualization of the last hidden layer of decoder. We can see that the contrastive head can separate different classes in visual space." + ], + "image_footnote": [], + "bbox": [ + 509, + 94, + 687, + 237 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/e0c24144bb6a945924f28443a81db028ce76c24751dc526ed9e377bc10b8566b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 705, + 94, + 883, + 237 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/ec9805989e4ed217a78e22449565b12739f81500cbf5ffd6ce8dfbb33f02af2d.jpg", + "image_caption": [ + "Figure 5. The effect of number of queries and positive rate of $C_{\\pi}$" + ], + "image_footnote": [], + "bbox": [ + 540, + 310, + 849, + 448 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "reconstruction loss can further separate different classes in visual space and bring a higher intra-class compactness and inter-class separability of the visual structure.", + "bbox": [ + 496, + 500, + 890, + 544 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Effect of number of queries and positive rate. We study the effect of number of queries $N$ and positive rate $\\lambda_{\\pi}$ of sampled class set $C_{\\pi}$ . We found that $\\lambda_{\\pi}$ have different influence under different number of queries $N$ . We change the positive rate $\\lambda_{\\pi}$ in different settings of $N$ and report the mAP of converged model in unseen classes. In each episode, we control $\\lambda_{\\pi}$ by sampling different number of negative classes. All models are trained for 500,000 episodes. The results are shown in Fig. 5. As we can see, a larger $N$ tends to have a better performance due to a higher recall, and of course a higher amount of calculation. Meanwhile, when $N$ is small (e.g. 100), a small positive rate will greatly reduce the amount of positive queries for training, thereby reducing the model performance. When $N$ is large (e.g. 900), the number of positive queries is guaranteed and more negative queries are needed for the classification head to learn to distinguish among them. Therefore, we can see the best performance is achieved when $\\lambda_{\\pi}$ is 0.5 and $N$ is 900.", + "bbox": [ + 496, + 545, + 892, + 816 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 830, + 617, + 845 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this paper, we present the first work that combine DETR and meta-learning to perform zero-shot object detection, which formalize the training as individual episode", + "bbox": [ + 496, + 854, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "6852", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "based meta-learning task. In each episode, we randomly sample an image and a class set. The meta-learning task is to make the model learn to detect all appeared classes of the sampled class set on the image. To achieve this, we train the decoder to directly predict class-specific boxes with class-specific queries as input, under the supervision of our meta-contrastive learning that contains three different heads. We conduct extensive experiments on the benchmark datasets MSCOCO and PASCAL VOC. Experimental results show that our method outperforms the existing ZSD methods. In the future, we will focus on further performance improvement.", + "bbox": [ + 75, + 90, + 472, + 271 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement. Jihong Guan was supported by National Natural Science Foundation of China (NSFC) under grant No. U1936205.", + "bbox": [ + 76, + 272, + 470, + 318 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 330, + 174, + 345 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Zeynep Akata, Florent Perronnin, Zaid Harchaoui, and Cordelia Schmid. Label-embedding for attribute-based classification. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 819–826, 2013. 2", + "[2] Ankan Bansal, Karan Sikka, Gaurav Sharma, Rama Chellappa, and Ajay Divakaran. Zero-shot object detection. In Proceedings of the European Conference on Computer Vision (ECCV), pages 384-400, 2018. 1, 2, 6", + "[3] Ankan Bansal, Karan Sikka, Gaurav Sharma, Rama Chellappa, and Ajay Divakaran. Zero-shot object detection. In ECCV, pages 384-400, 2018. 7", + "[4] Maxime Bucher, Stéphane Herbin, and Frédéric Jurie. Improving semantic embedding consistency by metric learning for zero-shot classification. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part V 14, pages 730-746. Springer, 2016. 2", + "[5] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part I 16, pages 213-229. Springer, 2020. 2", + "[6] Shiming Chen, Wenjie Wang, Beihao Xia, Qinmu Peng, Xinge You, Feng Zheng, and Ling Shao. Free: Feature refinement for generalized zero-shot learning. In Proceedings of the IEEE/CVF international conference on computer vision, pages 122-131, 2021. 2", + "[7] Berkan Demirel, Ramazan Gokberk Cinbis, and Nazli Ikizler-Cinbis. Zero-shot object detection by hybrid region embedding. arXiv preprint arXiv:1805.06157, 2018. 1, 2, 6", + "[8] Berkan Demirel, Ramazan Gokberk Cinbis, and Nazli Ikizler-Cinbis. Zero-shot object detection by hybrid region embedding. In BMVC, 2018. 6", + "[9] Mark Everingham, Luc Van Gool, Christopher KI Williams, John Winn, and Andrew Zisserman. The pascal visual object classes (voc) challenge. International journal of computer vision, 88:303-308, 2009. 6" + ], + "bbox": [ + 86, + 354, + 470, + 898 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[10] Yanwei Fu, Timothy M Hospedales, Tao Xiang, Zhenyong Fu, and Shaogang Gong. Transductive multi-view embedding for zero-shot recognition and annotation. In Computer Vision-ECCV 2014: 13th European Conference, Zurich, Switzerland, September 6-12, 2014, Proceedings, Part II 13, pages 584-599. Springer, 2014. 2", + "[11] Ross Girshick. Fast r-cnn. In Proceedings of the IEEE international conference on computer vision, pages 1440-1448, 2015. 2", + "[12] Dikshant Gupta, Aditya Anantharaman, Nehal Mamgain, Vineeth N Balasubramanian, CV Jawahar, et al. A multi-space approach to zero-shot object detection. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1209-1217, 2020. 1, 2", + "[13] Zongyan Han, Zhenyong Fu, and Jian Yang. Learning the redundancy-free features for generalized zero-shot object recognition. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 12865-12874, 2020. 2", + "[14] Nasir Hayat, Munawar Hayat, Shafin Rahman, Salman Khan, Syed Waqas Zamir, and Fahad Shahbaz Khan. Synthesizing the unseen for zero-shot object detection. In Proceedings of the Asian Conference on Computer Vision, 2020. 1, 2, 6", + "[15] Nasir Hayat, Munawar Hayat, Shafin Rahman, Salman Khan, Syed Waqas Zamir, and Fahad Shahbaz Khan. Synthesizing the unseen for zero-shot object detection. In ACCV, 2020. 6, 7", + "[16] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 6", + "[17] Peiliang Huang, Junwei Han, De Cheng, and Dingwen Zhang. Robust region feature synthesizer for zero-shot object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7622-7631, 2022. 1, 2, 6, 7", + "[18] Siddhesh Khandelwal, Anirudth Nambirajan, Behjat Siddique, Jayan Eledath, and Leonid Sigal. Frustratingly simple but effective zero-shot detection and segmentation: Analysis and a strong baseline. arXiv preprint arXiv:2302.07319, 2023. 1, 2", + "[19] Dahun Kim, Tsung-Yi Lin, Anelia Angelova, In So Kweon, and Weicheng Kuo. Learning open-world object proposals without learning to classify. IEEE Robotics and Automation Letters, 7(2):5453-5460, 2022. 1", + "[20] Diederik P Kingma and Max Welling. Auto-encoding variational bayes. arXiv preprint arXiv:1312.6114, 2013. 2", + "[21] Elyor Kodirov, Tao Xiang, and Shaogang Gong. Semantic autoencoder for zero-shot learning. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3174-3183, 2017. 2", + "[22] Zhihui Li, Lina Yao, Xiaoqin Zhang, Xianzhi Wang, Salil Kanhere, and Huaxiang Zhang. Zero-shot object detection with textual descriptions. In AAAI, volume 33, pages 8690-8697, 2019. 7" + ], + "bbox": [ + 501, + 92, + 890, + 898 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "6853", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[23] Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dólár. Focal loss for dense object detection. In Proceedings of the IEEE international conference on computer vision, pages 2980-2988, 2017. 2, 3, 5", + "[24] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólár, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In Computer Vision-ECCV 2014: 13th European Conference, Zurich, Switzerland, September 6-12, 2014, Proceedings, Part V 13, pages 740-755. Springer, 2014. 6", + "[25] Qiaomei Mao, Chong Wang, Shenghao Yu, Ye Zheng, and Yuqi Li. Zero-shot object detection with attributes-based category similarity. IEEE Transactions on Circuits and Systems II: Express Briefs, 67(5):921-925, 2020. 1, 2", + "[26] Tomas Mikolov, Edouard Grave, Piotr Bojanowski, Christian Puhrsch, and Armand Joulin. Advances in pretraining distributed word representations. arXiv preprint arXiv:1712.09405, 2017. 6", + "[27] Sanath Narayan, Akshita Gupta, Fahad Shahbaz Khan, Cees GM Snoek, and Ling Shao. Latent embedding feedback and discriminative features for zero-shot classification. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XXII 16, pages 479-495. Springer, 2020. 1, 2", + "[28] Aaron van den Oord, Yazhe Li, and Oriol Vinyals. Representation learning with contrastive predictive coding. arXiv preprint arXiv:1807.03748, 2018. 6", + "[29] Shafin Rahman, Salman Khan, and Nick Barnes. Improved visual-semantic alignment for zero-shot object detection. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 11932–11939, 2020. 6", + "[30] Shafin Rahman, Salman Khan, and Nick Barnes. Improved visual-semantic alignment for zero-shot object detection. In AAAI, volume 34, pages 11932–11939, 2020. 6, 7", + "[31] Shafin Rahman, Salman Khan, and Fatih Porikli. Zero-shot object detection: Learning to simultaneously recognize and localize novel concepts. In ACCV, pages 547-563. Springer, 2018. 6", + "[32] Shafin Rahman, Salman H Khan, and Fatih Porikli. Zero-shot object detection: Joint recognition and localization of novel concepts. International Journal of Computer Vision, 128:2979-2999, 2020. 1, 2", + "[33] Joseph Redmon, Santosh Divvala, Ross Girshick, and Ali Farhadi. You only look once: Unified, real-time object detection. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 779-788, 2016. 2", + "[34] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. In NIPS, 2015. 1", + "[35] Hamid Rezatofighi, Nathan Tsoi, JunYoung Gwak, Amir Sadeghian, Ian Reid, and Silvio Savarese. Generalized intersection over union: A metric and a loss for bounding box regression. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 658-666, 2019. 3, 5", + "[36] Edgar Schonfeld, Sayna Ebrahimi, Samarth Sinha, Trevor Darrell, and Zeynep Akata. Generalized zero-and few-shot" + ], + "bbox": [ + 78, + 90, + 470, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "learning via aligned variational autoencoders. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8247-8255, 2019. 2", + "[37] Flood Sung, Yongxin Yang, Li Zhang, Tao Xiang, Philip HS Torr, and Timothy M Hospedales. Learning to compare: Relation network for few-shot learning. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1199-1208, 2018. 2", + "[38] Yongqin Xian, Tobias Lorenz, Bernt Schiele, and Zeynep Akata. Feature generating networks for zero-shot learning. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5542-5551, 2018. 2", + "[39] Yongqin Xian, Saurabh Sharma, Bernt Schiele, and Zeynep Akata. f-vaegan-d2: A feature generating framework for any-shot learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 10275–10284, 2019. 2", + "[40] Caixia Yan, Xiaojun Chang, Minnan Luo, Huan Liu, Xiaoqin Zhang, and Qinghua Zheng. Semantics-guided contrastive network for zero-shot object detection. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 1, 2, 6, 7", + "[41] Caixia Yan, Qinghua Zheng, Xiaojun Chang, Minnan Luo, Chung-Hsing Yeh, and Alexander G Hauptman. Semantics-preserving graph propagation for zero-shot object detection. IEEE Transactions on Image Processing, 29:8163-8176, 2020. 1, 2", + "[42] Shizhen Zhao, Changxin Gao, Yuanjie Shao, Lerenhan Li, Changqian Yu, Zhong Ji, and Nong Sang. Gtnet: Generative transfer network for zero-shot object detection. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 12967-12974, 2020. 1, 2", + "[43] Ye Zheng and Li Cui. Zero-shot object detection with transformers. In 2021 IEEE International Conference on Image Processing (ICIP), pages 444-448. IEEE, 2021. 2, 7", + "[44] Ye Zheng, Ruoran Huang, Chuanqi Han, Xi Huang, and Li Cui. Background learnable cascade for zero-shot object detection. In Proceedings of the Asian Conference on Computer Vision, 2020. 1, 2", + "[45] Ye Zheng, Ruoran Huang, Chuanqi Han, Xi Huang, and Li Cui. Background learnable cascade for zero-shot object detection. In ACCV, 2020. 6, 7", + "[46] Ye Zheng, Jiahong Wu, Yongqiang Qin, Faen Zhang, and Li Cui. Zero-shot instance segmentation. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2593-2602, 2021. 2", + "[47] Pengkai Zhu, Hanxiao Wang, and Venkatesh Saligrama. Don't even look once: Synthesizing features for zero-shot detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11693-11702, 2020. 1, 2", + "[48] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable $\\{\\mathrm{detr}\\}$ : Deformable transformers for end-to-end object detection. In International Conference on Learning Representations, 2021. 2, 6" + ], + "bbox": [ + 501, + 92, + 890, + 868 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "6854", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/ab81a251-c4da-4048-9092-c84f97030f0f_model.json b/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/ab81a251-c4da-4048-9092-c84f97030f0f_model.json new file mode 100644 index 0000000000000000000000000000000000000000..a1349a8cbde16e8ba9a90e41ce776692aff363f5 --- /dev/null +++ b/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/ab81a251-c4da-4048-9092-c84f97030f0f_model.json @@ -0,0 +1,2398 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.216, + 0.131, + 0.757, + 0.154 + ], + "angle": 0, + "content": "Meta-ZSDETR: Zero-shot DETR with Meta-learning" + }, + { + "type": "text", + "bbox": [ + 0.165, + 0.18, + 0.812, + 0.199 + ], + "angle": 0, + "content": "Lu Zhang1 Chenbo Zhang1 Jiajia Zhao2 Jihong Guan3 Shuigeng Zhou1*" + }, + { + "type": "text", + "bbox": [ + 0.202, + 0.199, + 0.77, + 0.234 + ], + "angle": 0, + "content": "\\(^{1}\\)Shanghai Key Lab of Intelligent Information Processing, and School of Computer Science, Fudan University, China" + }, + { + "type": "text", + "bbox": [ + 0.254, + 0.234, + 0.717, + 0.27 + ], + "angle": 0, + "content": "\\(^{2}\\)Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory, China" + }, + { + "type": "text", + "bbox": [ + 0.189, + 0.27, + 0.782, + 0.288 + ], + "angle": 0, + "content": "\\(^{3}\\)Department of Computer Science & Technology, Tongji University, China" + }, + { + "type": "text", + "bbox": [ + 0.232, + 0.29, + 0.731, + 0.305 + ], + "angle": 0, + "content": "{1_zhang19,sgzhou}@fudan.edu.cn,cbzhang21@m.fudan.edu.cn" + }, + { + "type": "text", + "bbox": [ + 0.281, + 0.308, + 0.691, + 0.322 + ], + "angle": 0, + "content": "zhaojiajial982@gmail.com, jhguan@tongji.edu.cn" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.357, + 0.314, + 0.373 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.389, + 0.474, + 0.738 + ], + "angle": 0, + "content": "Zero-shot object detection aims to localize and recognize objects of unseen classes. Most of existing works face two problems: the low recall of RPN in unseen classes and the confusion of unseen classes with background. In this paper, we present the first method that combines DETR and meta-learning to perform zero-shot object detection, named Meta-ZSDETR, where model training is formalized as an individual episode based meta-learning task. Different from Faster R-CNN based methods that firstly generate class-agnostic proposals, and then classify them with visual-semantic alignment module, Meta-ZSDETR directly predict class-specific boxes with class-specific queries and further filter them with the predicted accuracy from classification head. The model is optimized with meta-contrastive learning, which contains a regression head to generate the coordinates of class-specific boxes, a classification head to predict the accuracy of generated boxes, and a contrastive head that utilizes the proposed contrastive-reconstruction loss to further separate different classes in visual space. We conduct extensive experiments on two benchmark datasets MS COCO and PASCAL VOC. Experimental results show that our method outperforms the existing ZSD methods by a large margin." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.763, + 0.21, + 0.78 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.789, + 0.471, + 0.88 + ], + "angle": 0, + "content": "Object detection [34] is one of the most fundamental tasks in computer vision. Most existing object detection methods require huge amounts of annotated training data, which is expensive and time-consuming to acquire. Meanwhile, in reality novel categories constantly emerge, and there is seriously lack or even nonexistent of visual data of" + }, + { + "type": "image", + "bbox": [ + 0.501, + 0.358, + 0.895, + 0.429 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.5, + 0.431, + 0.895, + 0.504 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.519, + 0.895, + 0.603 + ], + "angle": 0, + "content": "Figure 1. Zero-shot object detection: Faster R-CNN based methods vs. Meta-ZSDETR. (a): Faster R-CNN based methods firstly generate class-agnostic proposals, and then classify them with different visual-semantic alignment modules. (b): Meta-ZSDETR directly predict class-specific boxes with class-specific queries and further filter them with classification head." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.627, + 0.893, + 0.687 + ], + "angle": 0, + "content": "those novel categories for model training, such as endangered species in the wild. The above issues motivate the investigation of zero-shot object detection, which aims to localize and recognize objects of unseen classes." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.689, + 0.895, + 0.809 + ], + "angle": 0, + "content": "A mainstream framework of the existing works that are based on Faster R-CNN, is illustrated in Fig. 1(a), where the RPN remains unchanged and the RoI classification head is replaced with different visual-semantic alignment modules, such as mapping to the same embedding space to calculate similarity between proposals and semantic vectors [2, 40, 41, 32, 44, 12, 25, 18, 7], synthesizing visual features from semantic vectors [17, 14, 42, 47, 27] etc." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.895, + 0.901 + ], + "angle": 0, + "content": "However, we observe that the existing methods are suboptimal, due to their obvious inherent shortcomings: i) The proposals from RPN are often not reliable enough to cover all unseen classes objects in an image because of lacking training data, which has also been identified by a recent study [19]. ii) The confusion between background and un" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.888, + 0.225, + 0.9 + ], + "angle": 0, + "content": "* correspondence author" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6845" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.137 + ], + "angle": 0, + "content": "seen classes is an intractable problem. Although many previous works have tried to tackle it [46, 14, 2], the results are still unsatisfactory." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.14, + 0.47, + 0.32 + ], + "angle": 0, + "content": "Recently, object detection frameworks based on the Transformer have gained widespread popularity, such as DETR [5], Deformable DETR [48], etc. Such architectures are RPN-free and background-free, i.e., they do not involve RPN and background class, which are naturally conducive to building zero-shot object detection methods. However, how to build a ZSD method based on DETR detectors poses new challenges. An intuitive idea is to replace DETR's classification head with a zero-shot classifier based on cosine similarity [43]. However, such a method simply treats DETR as a large RPN for proposals generation, the overall framework is essentially the same as previous works." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.324, + 0.47, + 0.549 + ], + "angle": 0, + "content": "In this paper, we present the first method that fully explores DETR detectors and meta-learning to perform zero-shot object detection, named Meta-ZSDETR, which can solve the two problems mentioned above that have plagued the field of ZSD for many years, and achieves the state-of-the-art performance. The comparison of Meta-ZSDETR with previous methods is shown in Fig. 1. Different from the previous works that firstly generate class-agnostic proposals and then classify them with visual-semantic alignment module, our method utilizes semantic vectors to guide both proposal generation and classification, which greatly improves the recall of unseen classes. Meanwhile, there is no background class in DETR detectors, which means the confusion between background and unseen classes is no more existent." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.554, + 0.47, + 0.902 + ], + "angle": 0, + "content": "In order to detect unseen classes, we formalize the training process as an individual episode based meta-learning task. In each episode, we randomly sample an image \\( I \\) and a set of classes \\( C_{\\pi} \\), which contains the positive classes that appear in \\( I \\) and negative classes that do not appear. The meta-learning task is to make the model learn to detect all positive classes of \\( C_{\\pi} \\) on image \\( I \\). Through the meta-learning task, the training and testing can be unified, i.e., in the model testing, we need only to employ the unseen classes as the set \\( C_{\\pi} \\). To enable the model to detect an arbitrary class set, we firstly fuse each object query with a projected semantic vector from the class set \\( C_{\\pi} \\), which transfers the query from class-agnostic to class-specific. Then, the decoder takes the class-specific query as input and predicts the locations of class-specific boxes, together with the probabilities that the boxes belong to the fused class. To achieve the above goal, we propose meta-contrastive learning, where all predictions are split into three different types and different combinations of them are chosen to optimize three different heads, i.e., the regression head to generate the locations of class-specific boxes, the classification head to predict the accuracy of generated boxes, and the contrastive head to separate different classes in visual space for performance improving" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.151 + ], + "angle": 0, + "content": "with a contrastive-reconstruction loss. The bipartite matching and loss calculation are performed in a class-by-class manner, and the final loss is averaged over all classes in the sampled class set \\( \\mathcal{C}_{\\pi} \\)." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.153, + 0.862, + 0.167 + ], + "angle": 0, + "content": "In summary, our major contributions are as follows:" + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.178, + 0.892, + 0.253 + ], + "angle": 0, + "content": "- We present the first method that explores DETR and meta-learning to perform zero-shot object detection, which formalizes the training as an individual episode based meta-learning task and ingeniously tackles the two problems that plague ZSD for years." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.265, + 0.892, + 0.324 + ], + "angle": 0, + "content": "- We propose to train the decoder to directly predict class-specific boxes with class-specific queries as input, under the supervision of our meta-contrastive learning that contains three different heads." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.337, + 0.892, + 0.41 + ], + "angle": 0, + "content": "- We conduct extensive experiments on two benchmark datasets MSCOCO and PASCAL VOC to evaluate the proposed method Meta-ZSDETR. Experimental results show that our method outperforms the existing ZSD methods." + }, + { + "type": "list", + "bbox": [ + 0.519, + 0.178, + 0.892, + 0.41 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.426, + 0.638, + 0.442 + ], + "angle": 0, + "content": "2. Related work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.452, + 0.681, + 0.467 + ], + "angle": 0, + "content": "2.1. Zero-shot learning" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.475, + 0.892, + 0.656 + ], + "angle": 0, + "content": "Zero-shot learning (ZSL) aims to classify images of unseen classes that do not appear during training. There are two main streams in ZSL: embedding based methods and generative based methods. The key idea of embedding based methods is to learn an embedding function that maps the semantic vectors and visual features into the same embedding space, where the visual features and semantic vectors can be compared directly [1, 4, 10, 21, 37]. Generative based methods aim to synthesize unseen visual features with variational autoencoder [20] and generative adversarial networks [39], which convert the ZSL into a fully supervised way [6, 13, 36, 38]." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.667, + 0.738, + 0.683 + ], + "angle": 0, + "content": "2.2. Zero-shot object detection" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.689, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Zero-shot object detection (ZSD) has received a great deal of research interest in recent years. Most of ZSD methods are built on Faster R-CNN [11],YOLO [33] and RetinaNet [23]. The process of these methods can be summarized as: generating class-agnostic proposals and classifying proposals into seen/unseen and background classes. The main difference of these methods is that different visual semantic alignment methods are used to complete the classification of proposals. These methods can be divided into two categories: mapping the semantic vectors and visual features to the same embedding space to calculate similarity [2, 40, 41, 32, 44, 12, 25, 18, 7] and synthesizing visual features from semantic vectors [17, 14, 42, 47, 27]. Although previous works have paid great efforts, there are" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6846" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.181 + ], + "angle": 0, + "content": "some problems that still have no satisfactory solution, such as the low recall of class-agnostic RPN for unseen classes and the confusion between background and unseen classes. These problems may be caused by the incompatibility of ZSD task and proposals-based architecture such as Faster R-CNN." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.182, + 0.471, + 0.304 + ], + "angle": 0, + "content": "Different from previous works, Meta-ZSDETR is the first work built on Deformable DETR with meta-learning, where the semantic vectors are guided for class-specific boxes generation, instead of class-agnostic proposals in previous works, resulting in a higher unseen recall and precision. Meanwhile, since there is no background class in DETR detectors, the confusion between background and unseen classes is non-existent." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.317, + 0.168, + 0.332 + ], + "angle": 0, + "content": "3. Method" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.342, + 0.258, + 0.356 + ], + "angle": 0, + "content": "3.1. Problem definition" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.365, + 0.47, + 0.531 + ], + "angle": 0, + "content": "Zero-shot object detection (ZSD) aims to detect objects of unseen classes with model trained on the seen classes. Formally, the class space \\(\\mathcal{C}\\) in ZSD is divided into seen classes \\(\\mathcal{C}^s\\) and unseen classes \\(\\mathcal{C}^u\\), where \\(\\mathcal{C} = \\mathcal{C}^s \\cup \\mathcal{C}^u\\) and \\(\\mathcal{C}^s \\cap \\mathcal{C}^u = \\emptyset\\). The training set contains objects of seen classes, where each image \\(I\\) is provided with ground-truth class labels and bounding boxes coordinates. While the test set may contain only unseen objects (ZSD setting) or both seen and unseen classes (GZSD setting). During the training and testing, the semantic vectors \\(\\mathcal{W} = \\{\\mathcal{W}^s, \\mathcal{W}^u\\}\\) is provided for both seen and unseen classes." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.54, + 0.44, + 0.557 + ], + "angle": 0, + "content": "3.2. Revisit standard DETR in object detection" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.564, + 0.47, + 0.624 + ], + "angle": 0, + "content": "To begin with, we review the pipeline of a standard DETR in generic object detection, which contains the following steps: set prediction, optimal bipartite matching and loss calculation." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.643, + 0.229, + 0.658 + ], + "angle": 0, + "content": "3.2.1 Set prediction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.666, + 0.469, + 0.711 + ], + "angle": 0, + "content": "For an image \\(I\\), the global representation \\(x_{I}\\) is extracted by the backbone \\(f_{\\phi}\\) and Transformer encoder \\(g_{\\psi}\\) successively, which can be expressed as:" + }, + { + "type": "equation", + "bbox": [ + 0.217, + 0.724, + 0.469, + 0.74 + ], + "angle": 0, + "content": "\\[\nx _ {I} = g _ {\\psi} \\left(f _ {\\phi} (I)\\right) \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.753, + 0.47, + 0.8 + ], + "angle": 0, + "content": "Then, the decoder \\( g_{\\theta} \\) infers \\( N \\) object predictions \\( \\hat{\\mathcal{V}} \\), where \\( N \\) is determined by the number of object queries \\( \\mathcal{Q} \\) that serve as learnable positional embedding:" + }, + { + "type": "equation", + "bbox": [ + 0.22, + 0.81, + 0.469, + 0.827 + ], + "angle": 0, + "content": "\\[\n\\hat {\\mathcal {Y}} = g _ {\\theta} \\left(x _ {I}, \\mathcal {Q}\\right) \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.839, + 0.469, + 0.902 + ], + "angle": 0, + "content": "where \\(\\hat{\\mathcal{V}} = \\{(\\hat{c}_i,\\hat{b}_i)\\}_{i = 1}^N\\) and \\(\\mathcal{Q} = \\{q_i\\}_{i = 1}^N\\). For each object query \\(q_{i}\\), the decoder \\(g_{\\theta}\\) will output a prediction box, which contains two parts: the predicted class \\(\\hat{c}_i\\) and predicted box location \\(\\hat{b}_i\\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.092, + 0.747, + 0.107 + ], + "angle": 0, + "content": "3.2.2 Optimal bipartite matching" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.115, + 0.892, + 0.19 + ], + "angle": 0, + "content": "The optimal bipartite matching is to find the minimal-cost matching between the predictions \\(\\hat{\\mathcal{Y}} = \\{(\\hat{c}_i,\\hat{b}_i)\\}_{i = 1}^N\\) and ground-truth boxes \\(\\mathcal{V} = \\{(c_i,b_i)\\}_{i = 1}^N\\) (padded with no object \\(\\varnothing\\)). Therefore, we search for a permutation of \\(N\\) elements \\(\\sigma \\in \\mathfrak{S}_N\\) with lowest cost:" + }, + { + "type": "equation", + "bbox": [ + 0.527, + 0.2, + 0.892, + 0.241 + ], + "angle": 0, + "content": "\\[\n\\hat {\\sigma} = \\underset {\\sigma \\in \\mathfrak {S} _ {N}} {\\arg \\min } \\sum_ {i = 1} ^ {N} \\left[ \\mathcal {L} _ {c l s} \\left(c _ {i}, \\hat {c} _ {\\sigma_ {i}}\\right) + \\mathcal {L} _ {l o c} \\left(b _ {i}, \\hat {b} _ {\\sigma_ {i}}\\right) \\right] \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.253, + 0.892, + 0.345 + ], + "angle": 0, + "content": "where \\(\\mathcal{L}_{cls}(c_i,\\hat{c}_{\\sigma_i})\\) and \\(\\mathcal{L}_{loc}(b_i,\\hat{b}_{\\sigma_i})\\) are matching cost for class prediction and box location with index \\(\\sigma_{i}\\), respectively. Bipartite matching produces one-to-one assignments, where each prediction \\((\\hat{c}_i,\\hat{b}_i)\\) is assigned to either a ground-truth box \\((c_{i},b_{i})\\) or \\(\\varnothing\\) (no object). The permutation for lowest cost is calculated with Hungarian algorithm." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.362, + 0.661, + 0.377 + ], + "angle": 0, + "content": "3.2.3 Hungarian loss" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.386, + 0.891, + 0.416 + ], + "angle": 0, + "content": "Hungarian loss is a widely used loss function in DETR, which takes the following form:" + }, + { + "type": "equation", + "bbox": [ + 0.514, + 0.426, + 0.892, + 0.468 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {H u g} = \\sum_ {i = 1} ^ {N} \\left[ \\mathcal {L} _ {c l s} \\left(c _ {i}, \\hat {c} _ {\\hat {\\sigma} _ {i}}\\right) + \\mathbb {1} _ {\\{c _ {i} \\neq \\emptyset \\}} \\mathcal {L} _ {l o c} \\left(b _ {i}, \\hat {b} _ {\\hat {\\sigma} _ {i}}\\right) \\right] \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.476, + 0.892, + 0.537 + ], + "angle": 0, + "content": "where \\(\\hat{\\sigma}\\) is the optimal assignment computed in Eq.(3). \\(\\mathcal{L}_{cls}\\) is the loss for classification, which usually takes the form of focal loss [23] or cross-entropy loss. \\(\\mathcal{L}_{loc}\\) is the location loss and usually contains \\(l_{1}\\) loss and GIoU loss [35]." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.538, + 0.892, + 0.643 + ], + "angle": 0, + "content": "Challenge: Since the standard DETR can only locate the boxes and predict the classes of objects in training set, it is unable to detect unseen classes. In this paper, we utilize the meta-learning to make the model learn to detect objects according to the inputted semantic vectors, so that the model has the ability to detect objects of any category, as long as the semantic vector of the corresponding category is input." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.651, + 0.627, + 0.666 + ], + "angle": 0, + "content": "3.3. Framework" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.675, + 0.892, + 0.901 + ], + "angle": 0, + "content": "We present the framework of Meta-ZSDETR in Fig. 2, which is based on Deformable DETR. Meta-ZSDETR follows the paradigm of meta-learning. The training is performed by episode based meta-learning task. In each episode, we randomly sample an image \\(I\\) and a class set \\(\\mathcal{C}_{\\pi}\\). The meta-learning task of each episode is to make the model learn to detect all appeared classes in \\(\\mathcal{C}_{\\pi}\\) on image \\(I\\). Specifically, the image feature is firstly extracted by backbone and Transformer encoder as in Eq.(1). In order for the decoder to detect categories in \\(\\mathcal{C}_{\\pi}\\), we add the projected semantic vectors of classes \\(\\mathcal{C}_{\\pi}\\) to the object queries, making the queries class-specific. Then, the decoder takes the queries as input and predicts the class-specific boxes directly. To achieve this, the model is optimized with meta-contrastive learning, which contains a regression head to generate the" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6847" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.119, + 0.089, + 0.852, + 0.246 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.26, + 0.892, + 0.318 + ], + "angle": 0, + "content": "Figure 2. The framework of Meta-ZSDETR. In each episode, a class set \\( \\mathcal{C}_{\\pi} \\) and an image \\( I \\) are sampled. The meta-learning task is to make the model learn to detect all appeared classes in \\( \\mathcal{C}_{\\pi} \\). Firstly, the image feature \\( x_{I} \\) is extracted with backbone and encoder. Then, the projected semantic vectors are added to object queries, making them class-specific. Finally, the decoder \\( g_{\\theta} \\) will takes the queries as input and directly predict class-specific boxes. To achieve this, we train our model with proposed meta-contrastive learning." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.34, + 0.47, + 0.402 + ], + "angle": 0, + "content": "coordinates of class-specific boxes, a classification to predict the accuracy of generated boxes and a contrastive head that utilize the proposed contrastive-reconstruction loss to further separate different classes in visual space." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.412, + 0.433, + 0.429 + ], + "angle": 0, + "content": "3.4. Meta-ZSDETR with class-specific queries" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.437, + 0.47, + 0.512 + ], + "angle": 0, + "content": "To enable the model to detect any unseen class, we fuse the object queries with class semantic information, and make the model learn to predict the bounding boxes for the fused classes. Such a process is carried out in each meta-learning task." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.513, + 0.47, + 0.652 + ], + "angle": 0, + "content": "Specifically, in each episode, we randomly sample a class set \\(\\mathcal{C}_{\\pi}\\) and an image \\(I\\), where the \\(\\mathcal{C}_{\\pi}\\) satisfies \\(\\mathcal{C}_{\\pi} \\subseteq \\mathcal{C}^s\\) and each element is unique. Meanwhile, \\(\\mathcal{C}_{\\pi} = \\mathcal{C}_{\\pi}^{+} \\cup \\mathcal{C}_{\\pi}^{-}\\), where \\(\\mathcal{C}_{\\pi}^{+}\\) is the positive classes that appeared in image \\(I\\) and \\(\\mathcal{C}_{\\pi}^{-}\\) is the randomly sampled negative classes that do not appear in \\(I\\) for contrast. Meanwhile, we denote the size of \\(\\mathcal{C}_{\\pi}\\) as \\(L(\\mathcal{C}_{\\pi})\\), where \\(L(\\cdot)\\) is the operation that calculates size. The positive rate \\(\\frac{L(\\mathcal{C}_{\\pi}^{+})}{L(\\mathcal{C}_{\\pi})}\\) is set to \\(\\lambda_{\\pi}\\), which is a hyperparameter." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.653, + 0.47, + 0.699 + ], + "angle": 0, + "content": "Then, the corresponding semantic vectors \\(\\mathcal{W}_{\\pi}\\) of class set \\(\\mathcal{C}_{\\pi}\\) are projected from semantic space to the visual space with a linear layer \\(h_{\\mathcal{W}}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.217, + 0.713, + 0.469, + 0.733 + ], + "angle": 0, + "content": "\\[\n\\widetilde {\\mathcal {W} _ {\\pi}} = h _ {\\mathcal {W}} \\left(\\mathcal {W} _ {\\pi}\\right) \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.741, + 0.469, + 0.838 + ], + "angle": 0, + "content": "where \\(\\widetilde{\\mathcal{W}_{\\pi}}\\) is the projected semantic vectors of class set \\(\\mathcal{C}_{\\pi}\\). Since \\(L(\\widetilde{\\mathcal{W}_{\\pi}})\\ll N\\), i.e. the number of semantic vectors is smaller than the number of object queries \\(\\mathcal{Q}\\), we expand \\(\\widetilde{\\mathcal{W}_{\\pi}}\\) by duplicating each element in \\(\\widetilde{\\mathcal{W}_{\\pi}}\\) for \\(T\\) times, which satisfies \\(L(\\widetilde{\\mathcal{W}_{\\pi}})\\cdot T\\geqslant N\\) and \\(L(\\widetilde{\\mathcal{W}_{\\pi}})\\cdot (T - 1) < N\\). For redundant elements more than \\(N\\), we drop them." + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.839, + 0.469, + 0.871 + ], + "angle": 0, + "content": "Then, the projected semantic vectors \\(\\widetilde{\\mathcal{W}_{\\pi}}\\) is added to object queries \\(\\mathcal{Q}\\) as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.22, + 0.883, + 0.469, + 0.902 + ], + "angle": 0, + "content": "\\[\n\\mathcal {Q} _ {\\pi} = \\mathcal {Q} \\oplus \\widetilde {\\mathcal {W} _ {\\pi}} \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.34, + 0.892, + 0.386 + ], + "angle": 0, + "content": "where \\(\\mathcal{Q}_{\\pi} = \\{q_i^\\pi \\}_{i=1}^N\\) is the class-specific queries that will be inputted into the Transformer decoder \\(g_{\\theta}\\) with image feature \\(x_I\\) to generate predictions:" + }, + { + "type": "equation", + "bbox": [ + 0.639, + 0.397, + 0.892, + 0.415 + ], + "angle": 0, + "content": "\\[\n\\hat {\\mathcal {Y}} = g _ {\\theta} \\left(x _ {I}, \\mathcal {Q} _ {\\pi}\\right) \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.425, + 0.893, + 0.581 + ], + "angle": 0, + "content": "\\(\\hat{\\mathcal{V}} = \\{(\\hat{\\delta}_i,\\hat{b}_i)\\}_{i = 1}^N\\) is the set of predictions, where \\(\\hat{b}_i\\) is predicted box location generated with query \\(q_{i}^{\\pi}\\) and \\(\\hat{\\delta}_i\\) is the probability of box \\(\\hat{b}_i\\) belonging to the fused class, i.e. the class of semantic vector that fused to query \\(q_{i}^{\\pi}\\). Meanwhile, different from the standard DETR that the classification head determines the class of predicted boxes, the class of predicted box \\(\\hat{b}_i\\) in Meta-ZSDETR is class-specific and is determined by the class of corresponding query and \\(\\hat{\\delta}_i\\) only has one dimension to represent the probability of \\(\\hat{b}_i\\) belongs to the fused class." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.591, + 0.736, + 0.607 + ], + "angle": 0, + "content": "3.5. Meta-contrastive learning" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.614, + 0.892, + 0.764 + ], + "angle": 0, + "content": "In order for the regression head of decoder \\( g_{\\theta} \\) to generate more accurate class-specific box coordinate \\( \\hat{b}_i \\) and classification head to have a stronger discriminative ability of further judging the location accuracy of generated \\( \\hat{b}_i \\), we propose the meta-contrastive learning to train the heads of decoder \\( g_{\\theta} \\), i.e. a regression head to generate class-specific boxes, a classification head to filter inaccurate boxes, and moreover a contrastive head to further separate different classes in visual space, which will improve the performance of both seen classes and unseen classes." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.892, + 0.887 + ], + "angle": 0, + "content": "Meta-contrastive learning performs the matching and optimization in a class-by-class manner. As shown in Fig. 3, for each class \\( c_{j}^{\\pi} \\in \\mathcal{C}_{\\pi} \\), the decoder takes queries of class \\( c_{j}^{\\pi} \\) as input, and the predictions are split into three types: 1) The positive predictions that are assigned to GT box of class \\( c_{j}^{\\pi} \\) by class-specific bipartite matching. 2) The negative predictions that are assigned to any other classes than \\( c_{j}^{\\pi} \\). 3) The negative predictions that belong to background." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.887, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Then, we takes different combinations of three types" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6848" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.08, + 0.089, + 0.473, + 0.25 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.262, + 0.471, + 0.304 + ], + "angle": 0, + "content": "Figure 3. All predictions of class \\( c_{j}^{\\pi} \\) are split into three different types and different combinations of them are utilized to train three different heads." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.328, + 0.473, + 0.479 + ], + "angle": 0, + "content": "of predictions to train three heads: a) For the classification head, we take all predictions for the training and give them corresponding positive/negative class-specific targets for class \\( c_{j}^{\\pi} \\). b) For the regression head, since the regression head aims to generate class-specific boxes of class \\( c_{j}^{\\pi} \\), we only utilize the positive predictions for optimization. c) For the contrastive head, since our intention is to separate different classes in visual space, we only use positive predictions of class \\( c_{j}^{\\pi} \\) and negative predictions of other classes for contrastive-reconstruction loss." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.498, + 0.36, + 0.515 + ], + "angle": 0, + "content": "3.5.1 Class-specific bipartite matching" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.522, + 0.47, + 0.635 + ], + "angle": 0, + "content": "Our meta-contrastive learning performs the matching in a class-by-class manner. For class \\( c_{j}^{\\pi} \\in \\mathcal{C}_{\\pi} \\), the predictions generated by queries of class \\( c_{j}^{\\pi} \\) are selected for bipartite matching, which is denoted as \\( \\hat{\\mathcal{Y}}_{c_j^\\pi} = \\{(\\hat{\\delta}_{\\tau_i},\\hat{b}_{\\tau_i})\\}_{i = 1}^{T_\\tau} \\) where \\( \\{\\tau_i\\}_{i = 1}^{T_\\tau} \\) are the indexes for queries of class \\( c_{j}^{\\pi} \\) in \\( N \\) queries. Since each query is duplicated for \\( T \\) or \\( T - 1 \\) times, we denote the length uniformly as \\( T_{\\tau} \\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.636, + 0.47, + 0.702 + ], + "angle": 0, + "content": "Then, the ground-truth matching targets are revised for each class \\(c_{j}^{\\pi}\\in \\mathcal{C}_{\\pi}\\). The class-specific matching labels are denoted as \\(\\Delta_{c_j^\\pi} = \\{\\delta_i^{c_j^\\pi}\\}_{i = 1}^{T_\\tau}\\) (padded with no objects \\(\\varnothing\\)), which satisfy:" + }, + { + "type": "equation", + "bbox": [ + 0.2, + 0.713, + 0.47, + 0.748 + ], + "angle": 0, + "content": "\\[\n\\delta_ {i} ^ {c _ {j} ^ {\\pi}} = \\left\\{ \\begin{array}{l l} 1, & c _ {i} = c _ {j} ^ {\\pi} \\\\ 0, & c _ {i} \\neq c _ {j} ^ {\\pi} \\end{array} \\right. \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.757, + 0.471, + 0.853 + ], + "angle": 0, + "content": "where \\(c_{i}\\) is the origin class label for ground-truth box \\(b_{i}\\). The revised matching labels are generated according to whether \\(c_{i}\\) is equal to \\(c_{j}^{\\pi}\\). Then, the matching targets \\(\\mathcal{Y}_{c_j^\\pi} = \\{(\\delta_i^{c_j^\\pi}, b_i)\\}_{i=1}^{T_\\tau}\\) is utilized for bipartite matching of class \\(c_{j}^{\\pi}\\), where a permutation of \\(T_{\\tau}\\) elements \\(\\sigma \\in \\mathfrak{S}_{T_{\\tau}}\\) with lowest cost is search as:" + }, + { + "type": "equation", + "bbox": [ + 0.094, + 0.863, + 0.47, + 0.905 + ], + "angle": 0, + "content": "\\[\n\\hat {\\sigma} = \\underset {\\sigma \\in \\mathfrak {S} _ {T \\tau}} {\\arg \\min } \\sum_ {i = 1} ^ {T _ {\\tau}} \\left[ \\mathcal {L} _ {c l s} (\\delta_ {i} ^ {e _ {j} ^ {\\pi}}, \\hat {\\delta} _ {\\tau_ {\\sigma_ {i}}}) + \\mathcal {L} _ {l o c} (b _ {i}, \\hat {b} _ {\\tau_ {\\sigma_ {i}}}) \\right] \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.138 + ], + "angle": 0, + "content": "where \\(\\hat{\\sigma}\\) is the optimal assignment between matching targets \\(\\mathcal{V}_{c_j^\\pi}\\) and predictions \\(\\hat{\\mathcal{V}}_{c_j^\\pi}\\). \\(\\mathcal{L}_{cls}\\) and \\(\\mathcal{L}_{loc}\\) are the same as that in Eq.(3)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.155, + 0.649, + 0.168 + ], + "angle": 0, + "content": "3.5.2 Loss function" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.176, + 0.892, + 0.234 + ], + "angle": 0, + "content": "Based on \\(\\hat{\\sigma}\\), predictions in \\(\\hat{Y}_{c_j^\\pi}\\) are split into three types mentioned above, i.e. positive and two types of negative ones, and loss function of class \\(c_{j}^{\\pi}\\) for three heads are calculated as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.5, + 0.238, + 0.892, + 0.287 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {c _ {j} ^ {\\pi}} = \\sum_ {i = 1} ^ {T _ {\\tau}} \\left[ \\mathcal {L} _ {c l s} \\left(\\delta_ {i} ^ {c _ {j} ^ {\\pi}}, \\hat {\\delta} _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) + \\mathbb {1} _ {\\left(c _ {i} = c _ {j} ^ {\\pi}\\right)} \\mathcal {L} _ {l o c} \\left(b _ {i}, \\hat {b} _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) \\right] + \\mathcal {L} _ {c o n t} \\tag {10}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.288, + 0.892, + 0.333 + ], + "angle": 0, + "content": "where the loss \\(\\mathcal{L}_{c_j^\\pi}\\) for class \\(c_{j}^{\\pi}\\) is composed of classification loss \\(\\mathcal{L}_{cls}\\), regression loss \\(\\mathcal{L}_{loc}\\) and contrastive-reconstruction loss \\(\\mathcal{L}_{cont}\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.333, + 0.892, + 0.415 + ], + "angle": 0, + "content": "Classification loss. \\(\\mathcal{L}_{cls}\\) takes all predictions as input and makes the model learn to distinguish whether a predicted box belongs to \\(c_{j}^{\\pi}\\). The predicted box has the label \\(\\delta_{i}^{c_{j}^{\\pi}} = 1\\) if and only if it is assigned to a ground-truth box with class label \\(c_{j}^{\\pi}\\). We implement \\(\\mathcal{L}_{cls}\\) with focal loss [23]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.415, + 0.892, + 0.512 + ], + "angle": 0, + "content": "Regression loss. Since our intention is to generate class-specific boxes, i.e. input decoder with query of class \\(c_{j}^{\\pi}\\) and output box of class \\(c_{j}^{\\pi}\\), we only select the ground-truth box with class label \\(c_{j}^{\\pi}\\) for optimization, i.e. \\(\\delta_{i}^{c_{j}^{\\pi}} = 1\\), making the predicted boxes to be closer to GT boxes with class label \\(c_{j}^{\\pi}\\). The \\(\\mathcal{L}_{loc}\\) is implemented with \\(l_{1}\\) loss and GIoU loss [35]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.512, + 0.892, + 0.616 + ], + "angle": 0, + "content": "Contrastive-reconstruction loss. In ZSD tasks, the original visual space is not well-structured due to the lack of discriminative information, many previous works solved it by introducing a reconstruction loss to guide the distribution of visual features. Here, we combine the reconstruction loss and contrastive loss to bring a higher intra-class compactness and inter-class separability of the visual structure." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.617, + 0.892, + 0.74 + ], + "angle": 0, + "content": "In particular, we project the last hidden features of decoder to the semantic space, where the projected hidden features of positive predictions are constraint to be as close as possible to \\(\\omega_{j}^{\\pi}\\), which is the semantic vector of class \\(c_{j}^{\\pi}\\) and the negative ones are constraint to be as far as possible to \\(\\omega_{j}^{\\pi}\\). Formally, we denote the last hidden feature of optimal box \\((\\hat{\\delta}_{\\tau_{\\hat{\\sigma}_i}},\\hat{b}_{\\tau_{\\hat{\\sigma}_i}})\\) that matched to GT box \\((c_i,b_i)\\) as \\(z_{\\tau_{\\hat{\\sigma}_k}}\\) and the \\(\\mathcal{L}_{cont}\\) is formulated as:" + }, + { + "type": "equation", + "bbox": [ + 0.564, + 0.751, + 0.892, + 0.793 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {c o n t}} = \\frac {1}{N _ {\\text {p o s}}} \\sum_ {i = 1} ^ {T _ {\\tau}} \\mathbb {1} _ {\\left(c _ {i} = c _ {j} ^ {\\pi}\\right)} \\mathcal {L} _ {\\text {c o n t}} \\left(z _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) \\tag {11}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.501, + 0.803, + 0.892, + 0.855 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {c o n t}} \\left(z _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) = - \\log \\frac {\\exp \\left[ h _ {\\rho} \\left(z _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) \\cdot \\omega_ {j} ^ {\\pi} / \\kappa \\right]}{\\sum_ {k = 1} ^ {T _ {\\tau}} \\mathbb {1} _ {(c _ {k} \\neq \\varnothing)} \\exp \\left[ h _ {\\rho} \\left(z _ {\\tau_ {\\hat {\\sigma} _ {k}}}\\right) \\cdot \\omega_ {j} ^ {\\pi} / \\kappa \\right]} \\tag {12}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.892, + 0.903 + ], + "angle": 0, + "content": "where \\( h_{\\rho} \\) is a linear layer that projects the hidden feature to the semantic space. \\( N_{pos} \\) is the number of positive predictions of class \\( c_{j}^{\\pi} \\). \\( \\kappa \\) is a temperature hyper-parameter" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6849" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.091, + 0.47, + 0.167 + ], + "angle": 0, + "content": "as in InfoNCE [28]. The optimization of the above loss function increases the instance-level similarity between projected hidden features of positive predictions with semantic vector \\(\\omega_{j}^{\\pi}\\) and space the negative ones. As a result, visual features of the same class will form a tighter cluster." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.168, + 0.47, + 0.243 + ], + "angle": 0, + "content": "Total loss function. We compute the loss function with Eq.(10) for each class \\( c_{j}^{\\pi} \\in \\mathcal{C}_{\\pi} \\), separately. For negative classes \\( \\mathcal{C}_{\\pi}^{-} \\), only classification loss is calculated. Finally, the loss of current episode is averaged over all classes in sampled class set \\( \\mathcal{C}_{\\pi} \\):" + }, + { + "type": "equation", + "bbox": [ + 0.198, + 0.248, + 0.469, + 0.293 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} = \\frac {1}{L \\left(\\mathcal {C} _ {\\pi}\\right)} \\sum_ {j = 1} ^ {L \\left(\\mathcal {C} _ {\\pi}\\right)} \\mathcal {L} _ {c _ {j} ^ {\\pi}} \\tag {13}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.298, + 0.47, + 0.329 + ], + "angle": 0, + "content": "where \\(L(\\mathcal{C}_{\\pi})\\) is the number of classes in \\(\\mathcal{C}_{\\pi}\\). We utilize \\(\\mathcal{L}\\) for model optimization." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.34, + 0.21, + 0.357 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.364, + 0.258, + 0.381 + ], + "angle": 0, + "content": "4.1. Datasets and splits" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.387, + 0.47, + 0.432 + ], + "angle": 0, + "content": "Following previous works [40, 17], we takes two benchmark datasets for evaluation: PASCAL VOC 2007+2012 [9] and MS COCO 2014 [24]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.433, + 0.47, + 0.599 + ], + "angle": 0, + "content": "Datasets: PASCAL VOC contains 20 classes of objects for object detection. More specifically, the PASCAL VOC 2,007 is composed of 2,501 training images, 2,510 validation images, and 5,011 test images. The PASCAL VOC 2012 dataset comprises 5,717 training images and 5,823 validation images, without test images released. MS COCO 2014 is a benchmark dataset designed for object detection and semantic segmentation tasks, which contains 82,783 training and 40,504 validation images from 80 categories. For PASCAL VOC and MS COCO, we adopt the Fast-Text [26] to extract the semantic vectors following [14, 17]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.599, + 0.469, + 0.705 + ], + "angle": 0, + "content": "Seen/unseen splits: All splits follow the previous setting [40, 17]. For PASCAL VOC, we use a 16/4 split proposed in [7]. For MS COCO, we follow the same procedures described in [2, 29, 17] to take 2 different splits, i.e. 48/17 and 65/15. For all datasets, the images that contain unseen classes in the training set are removed to guarantee that unseen objects will not be available during training." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.712, + 0.273, + 0.728 + ], + "angle": 0, + "content": "4.2. Evaluation protocols" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.469, + 0.84 + ], + "angle": 0, + "content": "We adopt the widely-used evaluation protocols proposed in [2, 7]. For PASCAL VOC, mAP with IoU threshold 0.5 is used to evaluate the performance. For MS COCO, mAP and recall@100 with three different IoU threshold (i.e. 0.4, 0.5 and 0.6) are utilized for evaluation. For GZSD setting that contains both seen and unseen classes, the performance is evaluated by Harmonic Mean (HM)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.848, + 0.292, + 0.864 + ], + "angle": 0, + "content": "4.3. Implementation details" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.469, + 0.901 + ], + "angle": 0, + "content": "We build Meta-ZSDETR on Deformable DETR [48] with ResNet-50 [16] as backbone. The number of queries" + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.089, + 0.89, + 0.263 + ], + "angle": 0, + "content": "
MethodZSDGZSD
SUHM
SAN [31]59.148.037.041.8
HRE [8]54.262.425.536.2
PL [30]62.1---
BLC [45]55.258.222.932.9
SU [15]64.9---
Robust-Syn [17]65.547.149.148.1
ContrastZSD [40]65.763.246.553.6
Meta-ZSDETR70.367.656.361.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.272, + 0.892, + 0.314 + ], + "angle": 0, + "content": "Table 1. The results of mAP in PASCAL VOC with IoU=0.5 under ZSD and GZSD settings. Here, \"S\" denotes seen classes, \"U\" denotes unseen classes and \"HM\" denotes harmonic mean." + }, + { + "type": "table", + "bbox": [ + 0.503, + 0.325, + 0.891, + 0.478 + ], + "angle": 0, + "content": "
MethodcardogsofatrainmAP
SAN [31]56.285.362.626.457.6
HRE [8]55.082.055.026.054.5
PL [30]63.787.253.244.162.1
BLC [45]43.78660.830.155.2
SU [15]59.692.762.345.264.9
Robust-Syn [17]60.193.059.749.165.5
ContrastZSD [40]65.586.463.147.965.7
Meta-ZSDETR69.092.465.754.170.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.487, + 0.892, + 0.515 + ], + "angle": 0, + "content": "Table 2. Class-wise AP and mAP on unseen classes in PASCAL VOC under ZSD setting." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.541, + 0.892, + 0.737 + ], + "angle": 0, + "content": "\\(N\\) is set to 900. For the sampled class set \\(\\mathcal{C}_{\\pi}\\), the positive classes consist of the classes that appear in the image and the negative classes is sampled from \\(\\mathcal{C}^s\\). The positive rate \\(\\lambda_{\\pi}\\) is set to 0.5. The number of Transformer encoder layers and decoder layers is set to 6. The temperature hyperparameter \\(\\kappa\\) in Eq.(12) is set to 0.2. We train our model for total 500,000 iterations with batch size 16, i.e. each iteration contains 16 episodes in parallel. Following Deformable DETR, different coefficients are utilized to weight different loss functions, where 1.0 is used for classification loss, 5.0 is used for \\(l_1\\) loss of regression head, 2.0 is used for GIoU loss of regression head and 1.0 is used for contrastive-reconstruction loss. More details can refer to our code." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.748, + 0.803, + 0.764 + ], + "angle": 0, + "content": "4.4. Comparison with existing methods" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.771, + 0.659, + 0.785 + ], + "angle": 0, + "content": "4.4.1 PASCAL VOC" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.892, + 0.855 + ], + "angle": 0, + "content": "We present the results of PASCAL VOC in Tab. 1, where we can see that our method performs best among all existing methods under both ZSD and GZSD settings, and lift the mAP in PASCAL VOC to a higher level." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Specifically, in ZSD setting, Meta-ZSDETR achieves 70.3 mAP and outperform the second-best model ContrastZSD [40] by a large margin of 4.6 mAP, which is the" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "6850" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.078, + 0.09, + 0.48, + 0.376 + ], + "angle": 0, + "content": "
MethodSplitRecall@100mAP
IoU=0.4IoU=0.5IoU=0.6IoU=0.5
DSES [3]48/1740.227.213.60.5
TD [22]48/1745.534.318.1-
PL [30]48/17-43.5-10.1
BLC [45]48/1751.348.845.010.6
ZSDTR [43]48/1751.848.544.510.4
Robust-Syn [17]48/1758.153.547.913.4
ContrastZSD [40]48/1756.152.447.212.5
Meta-ZSDETR48/1762.359.854.215.1
PL [30]65/15-37.7-12.4
BLC [45]65/1557.254.751.214.7
SU [15]65/1554.454.047.019.0
ZSDTR [43]65/1563.860.356.513.2
Robust-Syn [17]65/1565.362.355.919.8
ContrastZSD [40]65/1562.359.555.118.6
Meta-ZSDETR65/1569.166.759.022.5
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.076, + 0.385, + 0.47, + 0.414 + ], + "angle": 0, + "content": "Table 3. ZSD performance of Recall@100 and mAP with different IoU thresholds on MS COCO dataset." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.436, + 0.47, + 0.465 + ], + "angle": 0, + "content": "first time to boost the performance of ZSD setting on PASCAL VOC to over \\(70\\mathrm{mAP}\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.467, + 0.47, + 0.634 + ], + "angle": 0, + "content": "For GZSD setting, our method also achieves SOTAs in all three metrics, i.e. mAP on seen classes, unseen classes and harmonic mean, which brings about 4.4, 9.8 and 7.8 points improvement, respectively. It is worth noting that the improvement of our method on unseen classes in GZSD setting is extremely large, which proves that our method has a strong generalization on unseen classes, and can alleviate the problem that the unseen classes tend to be misclassified into seen classes to a certain extent. We also report class-wise mAP in ZSD setting in Tab. 2, where our method achieves the best performance on 3 classes." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.651, + 0.21, + 0.665 + ], + "angle": 0, + "content": "4.4.2 MS COCO" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.674, + 0.47, + 0.735 + ], + "angle": 0, + "content": "We perform experiments on MS COCO, where the results of ZSD setting is shown in Tab. 3 and the results of GZSD setting is shown in Tab. 4. We can see that Meta-ZSDETR achieves the best results in all metrics under all settings." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.47, + 0.87 + ], + "angle": 0, + "content": "For ZSD setting, we can see that mAP of our method in 48/17 and 65/15 splits outperforms the second-best by a margin of 1.7 and \\(2.7\\mathrm{mAP}\\), respectively, which demonstrates that our method generalizes well to unseen classes. Meanwhile, we can see that Recall@100 decrease as the IoU increases in all methods. Compared with other methods, Meta-ZSDETR has a smaller drop, which is benefit from that our decoder can generate more accurate boxes with class semantic information as input." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.47, + 0.901 + ], + "angle": 0, + "content": "For GZSD setting, our method achieves SOTAs in both seen and unseen classes. The harmonic means of mAP un" + }, + { + "type": "table", + "bbox": [ + 0.501, + 0.09, + 0.902, + 0.346 + ], + "angle": 0, + "content": "
MethodSplitRecall@100mAP
SUHMSUHM
PL [30]48/1738.226.331.235.94.17.4
BLC [45]48/1757.646.451.442.14.58.2
ZSDTR [43]48/1774.348.460.548.55.69.5
Robust-Syn [17]48/1759.758.859.242.313.420.4
ContrastZSD [40]48/1765.752.458.345.16.311.1
Meta-ZSDETR48/1774.359.065.848.714.622.5
PL [30]65/1536.437.236.834.112.418.2
BLC [45]65/1556.451.753.936.013.119.2
SU [15]65/1557.753.955.836.919.025.1
ZSDTR [43]65/1569.159.561.140.613.220.2
Robust-Syn [17]65/1558.661.860.237.419.826.0
ContrastZSD [40]65/1562.958.660.740.216.523.4
Meta-ZSDETR65/1571.165.468.145.921.729.5
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.499, + 0.355, + 0.892, + 0.383 + ], + "angle": 0, + "content": "Table 4. GZSD performance of Recall@100 and mAP with IoU=0.5 on MS COCO dataset." + }, + { + "type": "table", + "bbox": [ + 0.558, + 0.393, + 0.836, + 0.486 + ], + "angle": 0, + "content": "
LocClsContSeenUnseen
✓39.914.5
✓✓44.820.6
✓✓40.615.3
✓✓✓45.921.7
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.5, + 0.495, + 0.89, + 0.51 + ], + "angle": 0, + "content": "Table 5. Ablation study of different combinations of loss functions." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.535, + 0.892, + 0.642 + ], + "angle": 0, + "content": "der 48/17 and 65/15 splits are improved from 20.4 to 22.5, and from 26.0 to 29.5, demonstrating the effectiveness and superiority of our method. Meanwhile, the Recall@100 also improves due to the powerful class-specific boxes generation capabilities. We also report the class-wise AP in 65/15 split of MS COCO, which can be found in our supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.651, + 0.651, + 0.667 + ], + "angle": 0, + "content": "4.5. Ablation study" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.674, + 0.892, + 0.735 + ], + "angle": 0, + "content": "We analyze the effects of various components in Meta-ZSDETR. Unless otherwise specified, the experiments are carried out on MS COCO with 65/15 split under GZSD setting and use mAP with IoU=0.5 as metric." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Effects of different loss functions. Here, we analyze the effects of three loss functions in meta-contrastive learning. We utilize different combinations of regression loss \\(\\mathcal{L}_{loc}\\), classification loss \\(\\mathcal{L}_{cls}\\) and contrastive-reconstruction loss \\(\\mathcal{L}_{cont}\\) to optimize the model, and show the results in Tab. 5. Since the regression loss is necessary, we keep it for all combinations. For model without classification loss \\(\\mathcal{L}_{cls}\\), we do not perform the boxes filter and directly use the class-specific boxes predicted from regression head, where the scores are generated randomly. As we can see, if the model is only trained with regression head to gen" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "6851" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.089, + 0.089, + 0.46, + 0.244 + ], + "angle": 0, + "content": "
Heads\\( \\hat{y}_{pos} \\)\\( \\hat{y}_{other} \\)\\( \\hat{y}_{bg} \\)SeenUnseen
Classification Head✓✓43.717.9
✓✓44.819.0
✓✓✓45.921.7
Regression Head✓45.921.7
✓✓42.116.5
Contrastive Head✓45.121.0
✓✓45.921.7
✓✓✓45.421.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.254, + 0.47, + 0.281 + ], + "angle": 0, + "content": "Table 6. Ablation study on using different combinations of predictions to train three heads." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.307, + 0.47, + 0.457 + ], + "angle": 0, + "content": "erate class-specific boxes, it can achieve a mAP of 14.5 in unseen classes, which is relatively low, but also surpasses many previous methods. Adding the classification loss will greatly boost the performance of unseen classes to \\(20.6\\mathrm{mAP}\\), which thanks to the powerful discriminative ability of the classification head that can filter inaccurate boxes. Meanwhile, the contrastive-reconstruction loss can improve the performance with and without the classification head about 1 point. Finally, the combination of three losses achieves the best performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.459, + 0.471, + 0.809 + ], + "angle": 0, + "content": "Study for training of different heads. As describe, based on the class-specific bipartite matching for class \\( c_{j}^{\\pi} \\), all predictions are split into three different types: the positive predictions \\( \\hat{Y}_{pos} \\) assigned to GT boxes of \\( c_{j}^{\\pi} \\), the negative predictions \\( \\hat{Y}_{other} \\) assigned to other classes and the negative predictions \\( \\hat{Y}_{bg} \\) that belong to background. Here, we study different combinations of them to train three heads and the results are shown in Tab. 6. We can see that: 1) For classification head, since it aims to filter all kinds of negative predictions, using all predictions to train it can achieve the best performance. 2) For regression head, if we train it with GT boxes of all classes, i.e. using \\( \\hat{Y}_{pos} \\) and \\( \\hat{Y}_{other} \\), the regression head will degenerate into a class-agnostic RPN, which will greatly reduce the recall of unseen classes, thus lead to a lower mAP. 3) For contrastive head, on one hand, if we only use \\( \\hat{Y}_{pos} \\) for training, it will degenerate into a reconstruction loss, which has been widely used in previous works and it will bring a 0.4 mAP improvement in unseen classes compared with the version without it. On the other hand, compared with using all predictions, removing background predictions will make the contrastive head focus on distinguishing \\( \\hat{Y}_{other} \\) and inputed semantic vectors of class \\( c_{j}^{\\pi} \\), thus brings more improvement." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.811, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Visualization for contrastive-reconstruction loss. Here, we study the influence of contrastive-reconstruction loss on visual space by visualizing the distribution of hidden features with t-SNE. We visualize the last hidden features of decoder in unseen classes of PASCAL VOC. The result is shown in Fig. 4. As we can see, our contrastive" + }, + { + "type": "image", + "bbox": [ + 0.511, + 0.095, + 0.688, + 0.238 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.706, + 0.095, + 0.885, + 0.238 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.255, + 0.892, + 0.298 + ], + "angle": 0, + "content": "Figure 4. The t-SNE visualization of the last hidden layer of decoder. We can see that the contrastive head can separate different classes in visual space." + }, + { + "type": "image", + "bbox": [ + 0.541, + 0.311, + 0.851, + 0.449 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.462, + 0.882, + 0.477 + ], + "angle": 0, + "content": "Figure 5. The effect of number of queries and positive rate of \\( C_{\\pi} \\)" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.501, + 0.892, + 0.545 + ], + "angle": 0, + "content": "reconstruction loss can further separate different classes in visual space and bring a higher intra-class compactness and inter-class separability of the visual structure." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.546, + 0.893, + 0.818 + ], + "angle": 0, + "content": "Effect of number of queries and positive rate. We study the effect of number of queries \\(N\\) and positive rate \\(\\lambda_{\\pi}\\) of sampled class set \\(C_{\\pi}\\). We found that \\(\\lambda_{\\pi}\\) have different influence under different number of queries \\(N\\). We change the positive rate \\(\\lambda_{\\pi}\\) in different settings of \\(N\\) and report the mAP of converged model in unseen classes. In each episode, we control \\(\\lambda_{\\pi}\\) by sampling different number of negative classes. All models are trained for 500,000 episodes. The results are shown in Fig. 5. As we can see, a larger \\(N\\) tends to have a better performance due to a higher recall, and of course a higher amount of calculation. Meanwhile, when \\(N\\) is small (e.g. 100), a small positive rate will greatly reduce the amount of positive queries for training, thereby reducing the model performance. When \\(N\\) is large (e.g. 900), the number of positive queries is guaranteed and more negative queries are needed for the classification head to learn to distinguish among them. Therefore, we can see the best performance is achieved when \\(\\lambda_{\\pi}\\) is 0.5 and \\(N\\) is 900." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.831, + 0.619, + 0.846 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "In this paper, we present the first work that combine DETR and meta-learning to perform zero-shot object detection, which formalize the training as individual episode" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6852" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.272 + ], + "angle": 0, + "content": "based meta-learning task. In each episode, we randomly sample an image and a class set. The meta-learning task is to make the model learn to detect all appeared classes of the sampled class set on the image. To achieve this, we train the decoder to directly predict class-specific boxes with class-specific queries as input, under the supervision of our meta-contrastive learning that contains three different heads. We conduct extensive experiments on the benchmark datasets MSCOCO and PASCAL VOC. Experimental results show that our method outperforms the existing ZSD methods. In the future, we will focus on further performance improvement." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.273, + 0.472, + 0.319 + ], + "angle": 0, + "content": "Acknowledgement. Jihong Guan was supported by National Natural Science Foundation of China (NSFC) under grant No. U1936205." + }, + { + "type": "title", + "bbox": [ + 0.08, + 0.331, + 0.175, + 0.347 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.355, + 0.47, + 0.424 + ], + "angle": 0, + "content": "[1] Zeynep Akata, Florent Perronnin, Zaid Harchaoui, and Cordelia Schmid. Label-embedding for attribute-based classification. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 819–826, 2013. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.426, + 0.472, + 0.48 + ], + "angle": 0, + "content": "[2] Ankan Bansal, Karan Sikka, Gaurav Sharma, Rama Chellappa, and Ajay Divakaran. Zero-shot object detection. In Proceedings of the European Conference on Computer Vision (ECCV), pages 384-400, 2018. 1, 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.482, + 0.47, + 0.523 + ], + "angle": 0, + "content": "[3] Ankan Bansal, Karan Sikka, Gaurav Sharma, Rama Chellappa, and Ajay Divakaran. Zero-shot object detection. In ECCV, pages 384-400, 2018. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.525, + 0.47, + 0.607 + ], + "angle": 0, + "content": "[4] Maxime Bucher, Stéphane Herbin, and Frédéric Jurie. Improving semantic embedding consistency by metric learning for zero-shot classification. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part V 14, pages 730-746. Springer, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.608, + 0.47, + 0.69 + ], + "angle": 0, + "content": "[5] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part I 16, pages 213-229. Springer, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.691, + 0.47, + 0.761 + ], + "angle": 0, + "content": "[6] Shiming Chen, Wenjie Wang, Beihao Xia, Qinmu Peng, Xinge You, Feng Zheng, and Ling Shao. Free: Feature refinement for generalized zero-shot learning. In Proceedings of the IEEE/CVF international conference on computer vision, pages 122-131, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.761, + 0.469, + 0.803 + ], + "angle": 0, + "content": "[7] Berkan Demirel, Ramazan Gokberk Cinbis, and Nazli Ikizler-Cinbis. Zero-shot object detection by hybrid region embedding. arXiv preprint arXiv:1805.06157, 2018. 1, 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.804, + 0.469, + 0.845 + ], + "angle": 0, + "content": "[8] Berkan Demirel, Ramazan Gokberk Cinbis, and Nazli Ikizler-Cinbis. Zero-shot object detection by hybrid region embedding. In BMVC, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.088, + 0.846, + 0.469, + 0.9 + ], + "angle": 0, + "content": "[9] Mark Everingham, Luc Van Gool, Christopher KI Williams, John Winn, and Andrew Zisserman. The pascal visual object classes (voc) challenge. International journal of computer vision, 88:303-308, 2009. 6" + }, + { + "type": "list", + "bbox": [ + 0.087, + 0.355, + 0.472, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.176 + ], + "angle": 0, + "content": "[10] Yanwei Fu, Timothy M Hospedales, Tao Xiang, Zhenyong Fu, and Shaogang Gong. Transductive multi-view embedding for zero-shot recognition and annotation. In Computer Vision-ECCV 2014: 13th European Conference, Zurich, Switzerland, September 6-12, 2014, Proceedings, Part II 13, pages 584-599. Springer, 2014. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.179, + 0.892, + 0.219 + ], + "angle": 0, + "content": "[11] Ross Girshick. Fast r-cnn. In Proceedings of the IEEE international conference on computer vision, pages 1440-1448, 2015. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.223, + 0.892, + 0.292 + ], + "angle": 0, + "content": "[12] Dikshant Gupta, Aditya Anantharaman, Nehal Mamgain, Vineeth N Balasubramanian, CV Jawahar, et al. A multi-space approach to zero-shot object detection. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1209-1217, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.295, + 0.892, + 0.363 + ], + "angle": 0, + "content": "[13] Zongyan Han, Zhenyong Fu, and Jian Yang. Learning the redundancy-free features for generalized zero-shot object recognition. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 12865-12874, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.367, + 0.892, + 0.435 + ], + "angle": 0, + "content": "[14] Nasir Hayat, Munawar Hayat, Shafin Rahman, Salman Khan, Syed Waqas Zamir, and Fahad Shahbaz Khan. Synthesizing the unseen for zero-shot object detection. In Proceedings of the Asian Conference on Computer Vision, 2020. 1, 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.439, + 0.892, + 0.493 + ], + "angle": 0, + "content": "[15] Nasir Hayat, Munawar Hayat, Shafin Rahman, Salman Khan, Syed Waqas Zamir, and Fahad Shahbaz Khan. Synthesizing the unseen for zero-shot object detection. In ACCV, 2020. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.497, + 0.892, + 0.552 + ], + "angle": 0, + "content": "[16] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.555, + 0.892, + 0.623 + ], + "angle": 0, + "content": "[17] Peiliang Huang, Junwei Han, De Cheng, and Dingwen Zhang. Robust region feature synthesizer for zero-shot object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7622-7631, 2022. 1, 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.627, + 0.892, + 0.695 + ], + "angle": 0, + "content": "[18] Siddhesh Khandelwal, Anirudth Nambirajan, Behjat Siddique, Jayan Eledath, and Leonid Sigal. Frustratingly simple but effective zero-shot detection and segmentation: Analysis and a strong baseline. arXiv preprint arXiv:2302.07319, 2023. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.699, + 0.892, + 0.754 + ], + "angle": 0, + "content": "[19] Dahun Kim, Tsung-Yi Lin, Anelia Angelova, In So Kweon, and Weicheng Kuo. Learning open-world object proposals without learning to classify. IEEE Robotics and Automation Letters, 7(2):5453-5460, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.757, + 0.892, + 0.785 + ], + "angle": 0, + "content": "[20] Diederik P Kingma and Max Welling. Auto-encoding variational bayes. arXiv preprint arXiv:1312.6114, 2013. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.788, + 0.892, + 0.843 + ], + "angle": 0, + "content": "[21] Elyor Kodirov, Tao Xiang, and Shaogang Gong. Semantic autoencoder for zero-shot learning. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3174-3183, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.845, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[22] Zhihui Li, Lina Yao, Xiaoqin Zhang, Xianzhi Wang, Salil Kanhere, and Huaxiang Zhang. Zero-shot object detection with textual descriptions. In AAAI, volume 33, pages 8690-8697, 2019. 7" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "6853" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[23] Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dólár. Focal loss for dense object detection. In Proceedings of the IEEE international conference on computer vision, pages 2980-2988, 2017. 2, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.149, + 0.47, + 0.233 + ], + "angle": 0, + "content": "[24] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólár, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In Computer Vision-ECCV 2014: 13th European Conference, Zurich, Switzerland, September 6-12, 2014, Proceedings, Part V 13, pages 740-755. Springer, 2014. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.234, + 0.471, + 0.289 + ], + "angle": 0, + "content": "[25] Qiaomei Mao, Chong Wang, Shenghao Yu, Ye Zheng, and Yuqi Li. Zero-shot object detection with attributes-based category similarity. IEEE Transactions on Circuits and Systems II: Express Briefs, 67(5):921-925, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.291, + 0.471, + 0.346 + ], + "angle": 0, + "content": "[26] Tomas Mikolov, Edouard Grave, Piotr Bojanowski, Christian Puhrsch, and Armand Joulin. Advances in pretraining distributed word representations. arXiv preprint arXiv:1712.09405, 2017. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.348, + 0.471, + 0.431 + ], + "angle": 0, + "content": "[27] Sanath Narayan, Akshita Gupta, Fahad Shahbaz Khan, Cees GM Snoek, and Ling Shao. Latent embedding feedback and discriminative features for zero-shot classification. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XXII 16, pages 479-495. Springer, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.433, + 0.47, + 0.473 + ], + "angle": 0, + "content": "[28] Aaron van den Oord, Yazhe Li, and Oriol Vinyals. Representation learning with contrastive predictive coding. arXiv preprint arXiv:1807.03748, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.475, + 0.47, + 0.531 + ], + "angle": 0, + "content": "[29] Shafin Rahman, Salman Khan, and Nick Barnes. Improved visual-semantic alignment for zero-shot object detection. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 11932–11939, 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.532, + 0.47, + 0.573 + ], + "angle": 0, + "content": "[30] Shafin Rahman, Salman Khan, and Nick Barnes. Improved visual-semantic alignment for zero-shot object detection. In AAAI, volume 34, pages 11932–11939, 2020. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.575, + 0.47, + 0.629 + ], + "angle": 0, + "content": "[31] Shafin Rahman, Salman Khan, and Fatih Porikli. Zero-shot object detection: Learning to simultaneously recognize and localize novel concepts. In ACCV, pages 547-563. Springer, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.632, + 0.47, + 0.687 + ], + "angle": 0, + "content": "[32] Shafin Rahman, Salman H Khan, and Fatih Porikli. Zero-shot object detection: Joint recognition and localization of novel concepts. International Journal of Computer Vision, 128:2979-2999, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.689, + 0.47, + 0.744 + ], + "angle": 0, + "content": "[33] Joseph Redmon, Santosh Divvala, Ross Girshick, and Ali Farhadi. You only look once: Unified, real-time object detection. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 779-788, 2016. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.746, + 0.47, + 0.787 + ], + "angle": 0, + "content": "[34] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. In NIPS, 2015. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.789, + 0.47, + 0.87 + ], + "angle": 0, + "content": "[35] Hamid Rezatofighi, Nathan Tsoi, JunYoung Gwak, Amir Sadeghian, Ian Reid, and Silvio Savarese. Generalized intersection over union: A metric and a loss for bounding box regression. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 658-666, 2019. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[36] Edgar Schonfeld, Sayna Ebrahimi, Samarth Sinha, Trevor Darrell, and Zeynep Akata. Generalized zero-and few-shot" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "learning via aligned variational autoencoders. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8247-8255, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.205 + ], + "angle": 0, + "content": "[37] Flood Sung, Yongxin Yang, Li Zhang, Tao Xiang, Philip HS Torr, and Timothy M Hospedales. Learning to compare: Relation network for few-shot learning. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1199-1208, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.207, + 0.892, + 0.261 + ], + "angle": 0, + "content": "[38] Yongqin Xian, Tobias Lorenz, Bernt Schiele, and Zeynep Akata. Feature generating networks for zero-shot learning. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5542-5551, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.263, + 0.892, + 0.33 + ], + "angle": 0, + "content": "[39] Yongqin Xian, Saurabh Sharma, Bernt Schiele, and Zeynep Akata. f-vaegan-d2: A feature generating framework for any-shot learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 10275–10284, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.333, + 0.892, + 0.4 + ], + "angle": 0, + "content": "[40] Caixia Yan, Xiaojun Chang, Minnan Luo, Huan Liu, Xiaoqin Zhang, and Qinghua Zheng. Semantics-guided contrastive network for zero-shot object detection. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 1, 2, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.403, + 0.892, + 0.471 + ], + "angle": 0, + "content": "[41] Caixia Yan, Qinghua Zheng, Xiaojun Chang, Minnan Luo, Chung-Hsing Yeh, and Alexander G Hauptman. Semantics-preserving graph propagation for zero-shot object detection. IEEE Transactions on Image Processing, 29:8163-8176, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.474, + 0.892, + 0.543 + ], + "angle": 0, + "content": "[42] Shizhen Zhao, Changxin Gao, Yuanjie Shao, Lerenhan Li, Changqian Yu, Zhong Ji, and Nong Sang. Gtnet: Generative transfer network for zero-shot object detection. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 12967-12974, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.545, + 0.892, + 0.586 + ], + "angle": 0, + "content": "[43] Ye Zheng and Li Cui. Zero-shot object detection with transformers. In 2021 IEEE International Conference on Image Processing (ICIP), pages 444-448. IEEE, 2021. 2, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.588, + 0.892, + 0.642 + ], + "angle": 0, + "content": "[44] Ye Zheng, Ruoran Huang, Chuanqi Han, Xi Huang, and Li Cui. Background learnable cascade for zero-shot object detection. In Proceedings of the Asian Conference on Computer Vision, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.644, + 0.892, + 0.685 + ], + "angle": 0, + "content": "[45] Ye Zheng, Ruoran Huang, Chuanqi Han, Xi Huang, and Li Cui. Background learnable cascade for zero-shot object detection. In ACCV, 2020. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.687, + 0.892, + 0.741 + ], + "angle": 0, + "content": "[46] Ye Zheng, Jiahong Wu, Yongqiang Qin, Faen Zhang, and Li Cui. Zero-shot instance segmentation. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2593-2602, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.743, + 0.892, + 0.811 + ], + "angle": 0, + "content": "[47] Pengkai Zhu, Hanxiao Wang, and Venkatesh Saligrama. Don't even look once: Synthesizing features for zero-shot detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11693-11702, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.813, + 0.892, + 0.869 + ], + "angle": 0, + "content": "[48] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable \\(\\{\\mathrm{detr}\\}\\): Deformable transformers for end-to-end object detection. In International Conference on Learning Representations, 2021. 2, 6" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.869 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "6854" + } + ] +] \ No newline at end of file diff --git a/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/ab81a251-c4da-4048-9092-c84f97030f0f_origin.pdf b/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/ab81a251-c4da-4048-9092-c84f97030f0f_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..5b8a577dcc2947acddabdd7aac16499e3ff8340b --- /dev/null +++ b/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/ab81a251-c4da-4048-9092-c84f97030f0f_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:9a78b7a2dda738e17ecb3c18f4f0a84be995a052fbff971776272d0ac3a47053 +size 1306190 diff --git a/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/full.md b/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/full.md new file mode 100644 index 0000000000000000000000000000000000000000..1c655e8623c6b041f6591048c6c54083d1e407c9 --- /dev/null +++ b/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/full.md @@ -0,0 +1,369 @@ +# Meta-ZSDETR: Zero-shot DETR with Meta-learning + +Lu Zhang1 Chenbo Zhang1 Jiajia Zhao2 Jihong Guan3 Shuigeng Zhou1* + +$^{1}$ Shanghai Key Lab of Intelligent Information Processing, and School of Computer Science, Fudan University, China + +$^{2}$ Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory, China + +$^{3}$ Department of Computer Science & Technology, Tongji University, China + +{1_zhang19,sgzhou}@fudan.edu.cn,cbzhang21@m.fudan.edu.cn + +zhaojiajial982@gmail.com, jhguan@tongji.edu.cn + +# Abstract + +Zero-shot object detection aims to localize and recognize objects of unseen classes. Most of existing works face two problems: the low recall of RPN in unseen classes and the confusion of unseen classes with background. In this paper, we present the first method that combines DETR and meta-learning to perform zero-shot object detection, named Meta-ZSDETR, where model training is formalized as an individual episode based meta-learning task. Different from Faster R-CNN based methods that firstly generate class-agnostic proposals, and then classify them with visual-semantic alignment module, Meta-ZSDETR directly predict class-specific boxes with class-specific queries and further filter them with the predicted accuracy from classification head. The model is optimized with meta-contrastive learning, which contains a regression head to generate the coordinates of class-specific boxes, a classification head to predict the accuracy of generated boxes, and a contrastive head that utilizes the proposed contrastive-reconstruction loss to further separate different classes in visual space. We conduct extensive experiments on two benchmark datasets MS COCO and PASCAL VOC. Experimental results show that our method outperforms the existing ZSD methods by a large margin. + +# 1. Introduction + +Object detection [34] is one of the most fundamental tasks in computer vision. Most existing object detection methods require huge amounts of annotated training data, which is expensive and time-consuming to acquire. Meanwhile, in reality novel categories constantly emerge, and there is seriously lack or even nonexistent of visual data of + +![](images/ccbc76cd1200013161c58b7b3c7df57dd1e2ae33624a33d52aee5575bfb2bd69.jpg) + +![](images/aafd1f74639b77112c331511209b22ff7d4d38d1cb4c2f1dcf971d11041e4343.jpg) +Figure 1. Zero-shot object detection: Faster R-CNN based methods vs. Meta-ZSDETR. (a): Faster R-CNN based methods firstly generate class-agnostic proposals, and then classify them with different visual-semantic alignment modules. (b): Meta-ZSDETR directly predict class-specific boxes with class-specific queries and further filter them with classification head. + +those novel categories for model training, such as endangered species in the wild. The above issues motivate the investigation of zero-shot object detection, which aims to localize and recognize objects of unseen classes. + +A mainstream framework of the existing works that are based on Faster R-CNN, is illustrated in Fig. 1(a), where the RPN remains unchanged and the RoI classification head is replaced with different visual-semantic alignment modules, such as mapping to the same embedding space to calculate similarity between proposals and semantic vectors [2, 40, 41, 32, 44, 12, 25, 18, 7], synthesizing visual features from semantic vectors [17, 14, 42, 47, 27] etc. + +However, we observe that the existing methods are suboptimal, due to their obvious inherent shortcomings: i) The proposals from RPN are often not reliable enough to cover all unseen classes objects in an image because of lacking training data, which has also been identified by a recent study [19]. ii) The confusion between background and un + +seen classes is an intractable problem. Although many previous works have tried to tackle it [46, 14, 2], the results are still unsatisfactory. + +Recently, object detection frameworks based on the Transformer have gained widespread popularity, such as DETR [5], Deformable DETR [48], etc. Such architectures are RPN-free and background-free, i.e., they do not involve RPN and background class, which are naturally conducive to building zero-shot object detection methods. However, how to build a ZSD method based on DETR detectors poses new challenges. An intuitive idea is to replace DETR's classification head with a zero-shot classifier based on cosine similarity [43]. However, such a method simply treats DETR as a large RPN for proposals generation, the overall framework is essentially the same as previous works. + +In this paper, we present the first method that fully explores DETR detectors and meta-learning to perform zero-shot object detection, named Meta-ZSDETR, which can solve the two problems mentioned above that have plagued the field of ZSD for many years, and achieves the state-of-the-art performance. The comparison of Meta-ZSDETR with previous methods is shown in Fig. 1. Different from the previous works that firstly generate class-agnostic proposals and then classify them with visual-semantic alignment module, our method utilizes semantic vectors to guide both proposal generation and classification, which greatly improves the recall of unseen classes. Meanwhile, there is no background class in DETR detectors, which means the confusion between background and unseen classes is no more existent. + +In order to detect unseen classes, we formalize the training process as an individual episode based meta-learning task. In each episode, we randomly sample an image $I$ and a set of classes $C_{\pi}$ , which contains the positive classes that appear in $I$ and negative classes that do not appear. The meta-learning task is to make the model learn to detect all positive classes of $C_{\pi}$ on image $I$ . Through the meta-learning task, the training and testing can be unified, i.e., in the model testing, we need only to employ the unseen classes as the set $C_{\pi}$ . To enable the model to detect an arbitrary class set, we firstly fuse each object query with a projected semantic vector from the class set $C_{\pi}$ , which transfers the query from class-agnostic to class-specific. Then, the decoder takes the class-specific query as input and predicts the locations of class-specific boxes, together with the probabilities that the boxes belong to the fused class. To achieve the above goal, we propose meta-contrastive learning, where all predictions are split into three different types and different combinations of them are chosen to optimize three different heads, i.e., the regression head to generate the locations of class-specific boxes, the classification head to predict the accuracy of generated boxes, and the contrastive head to separate different classes in visual space for performance improving + +with a contrastive-reconstruction loss. The bipartite matching and loss calculation are performed in a class-by-class manner, and the final loss is averaged over all classes in the sampled class set $\mathcal{C}_{\pi}$ . + +In summary, our major contributions are as follows: + +- We present the first method that explores DETR and meta-learning to perform zero-shot object detection, which formalizes the training as an individual episode based meta-learning task and ingeniously tackles the two problems that plague ZSD for years. +- We propose to train the decoder to directly predict class-specific boxes with class-specific queries as input, under the supervision of our meta-contrastive learning that contains three different heads. +- We conduct extensive experiments on two benchmark datasets MSCOCO and PASCAL VOC to evaluate the proposed method Meta-ZSDETR. Experimental results show that our method outperforms the existing ZSD methods. + +# 2. Related work + +# 2.1. Zero-shot learning + +Zero-shot learning (ZSL) aims to classify images of unseen classes that do not appear during training. There are two main streams in ZSL: embedding based methods and generative based methods. The key idea of embedding based methods is to learn an embedding function that maps the semantic vectors and visual features into the same embedding space, where the visual features and semantic vectors can be compared directly [1, 4, 10, 21, 37]. Generative based methods aim to synthesize unseen visual features with variational autoencoder [20] and generative adversarial networks [39], which convert the ZSL into a fully supervised way [6, 13, 36, 38]. + +# 2.2. Zero-shot object detection + +Zero-shot object detection (ZSD) has received a great deal of research interest in recent years. Most of ZSD methods are built on Faster R-CNN [11],YOLO [33] and RetinaNet [23]. The process of these methods can be summarized as: generating class-agnostic proposals and classifying proposals into seen/unseen and background classes. The main difference of these methods is that different visual semantic alignment methods are used to complete the classification of proposals. These methods can be divided into two categories: mapping the semantic vectors and visual features to the same embedding space to calculate similarity [2, 40, 41, 32, 44, 12, 25, 18, 7] and synthesizing visual features from semantic vectors [17, 14, 42, 47, 27]. Although previous works have paid great efforts, there are + +some problems that still have no satisfactory solution, such as the low recall of class-agnostic RPN for unseen classes and the confusion between background and unseen classes. These problems may be caused by the incompatibility of ZSD task and proposals-based architecture such as Faster R-CNN. + +Different from previous works, Meta-ZSDETR is the first work built on Deformable DETR with meta-learning, where the semantic vectors are guided for class-specific boxes generation, instead of class-agnostic proposals in previous works, resulting in a higher unseen recall and precision. Meanwhile, since there is no background class in DETR detectors, the confusion between background and unseen classes is non-existent. + +# 3. Method + +# 3.1. Problem definition + +Zero-shot object detection (ZSD) aims to detect objects of unseen classes with model trained on the seen classes. Formally, the class space $\mathcal{C}$ in ZSD is divided into seen classes $\mathcal{C}^s$ and unseen classes $\mathcal{C}^u$ , where $\mathcal{C} = \mathcal{C}^s \cup \mathcal{C}^u$ and $\mathcal{C}^s \cap \mathcal{C}^u = \emptyset$ . The training set contains objects of seen classes, where each image $I$ is provided with ground-truth class labels and bounding boxes coordinates. While the test set may contain only unseen objects (ZSD setting) or both seen and unseen classes (GZSD setting). During the training and testing, the semantic vectors $\mathcal{W} = \{\mathcal{W}^s, \mathcal{W}^u\}$ is provided for both seen and unseen classes. + +# 3.2. Revisit standard DETR in object detection + +To begin with, we review the pipeline of a standard DETR in generic object detection, which contains the following steps: set prediction, optimal bipartite matching and loss calculation. + +# 3.2.1 Set prediction + +For an image $I$ , the global representation $x_{I}$ is extracted by the backbone $f_{\phi}$ and Transformer encoder $g_{\psi}$ successively, which can be expressed as: + +$$ +x _ {I} = g _ {\psi} \left(f _ {\phi} (I)\right) \tag {1} +$$ + +Then, the decoder $g_{\theta}$ infers $N$ object predictions $\hat{\mathcal{V}}$ , where $N$ is determined by the number of object queries $\mathcal{Q}$ that serve as learnable positional embedding: + +$$ +\hat {\mathcal {Y}} = g _ {\theta} \left(x _ {I}, \mathcal {Q}\right) \tag {2} +$$ + +where $\hat{\mathcal{V}} = \{(\hat{c}_i,\hat{b}_i)\}_{i = 1}^N$ and $\mathcal{Q} = \{q_i\}_{i = 1}^N$ . For each object query $q_{i}$ , the decoder $g_{\theta}$ will output a prediction box, which contains two parts: the predicted class $\hat{c}_i$ and predicted box location $\hat{b}_i$ . + +# 3.2.2 Optimal bipartite matching + +The optimal bipartite matching is to find the minimal-cost matching between the predictions $\hat{\mathcal{Y}} = \{(\hat{c}_i,\hat{b}_i)\}_{i = 1}^N$ and ground-truth boxes $\mathcal{V} = \{(c_i,b_i)\}_{i = 1}^N$ (padded with no object $\varnothing$ ). Therefore, we search for a permutation of $N$ elements $\sigma \in \mathfrak{S}_N$ with lowest cost: + +$$ +\hat {\sigma} = \underset {\sigma \in \mathfrak {S} _ {N}} {\arg \min } \sum_ {i = 1} ^ {N} \left[ \mathcal {L} _ {c l s} \left(c _ {i}, \hat {c} _ {\sigma_ {i}}\right) + \mathcal {L} _ {l o c} \left(b _ {i}, \hat {b} _ {\sigma_ {i}}\right) \right] \tag {3} +$$ + +where $\mathcal{L}_{cls}(c_i,\hat{c}_{\sigma_i})$ and $\mathcal{L}_{loc}(b_i,\hat{b}_{\sigma_i})$ are matching cost for class prediction and box location with index $\sigma_{i}$ , respectively. Bipartite matching produces one-to-one assignments, where each prediction $(\hat{c}_i,\hat{b}_i)$ is assigned to either a ground-truth box $(c_{i},b_{i})$ or $\varnothing$ (no object). The permutation for lowest cost is calculated with Hungarian algorithm. + +# 3.2.3 Hungarian loss + +Hungarian loss is a widely used loss function in DETR, which takes the following form: + +$$ +\mathcal {L} _ {H u g} = \sum_ {i = 1} ^ {N} \left[ \mathcal {L} _ {c l s} \left(c _ {i}, \hat {c} _ {\hat {\sigma} _ {i}}\right) + \mathbb {1} _ {\{c _ {i} \neq \emptyset \}} \mathcal {L} _ {l o c} \left(b _ {i}, \hat {b} _ {\hat {\sigma} _ {i}}\right) \right] \tag {4} +$$ + +where $\hat{\sigma}$ is the optimal assignment computed in Eq.(3). $\mathcal{L}_{cls}$ is the loss for classification, which usually takes the form of focal loss [23] or cross-entropy loss. $\mathcal{L}_{loc}$ is the location loss and usually contains $l_{1}$ loss and GIoU loss [35]. + +Challenge: Since the standard DETR can only locate the boxes and predict the classes of objects in training set, it is unable to detect unseen classes. In this paper, we utilize the meta-learning to make the model learn to detect objects according to the inputted semantic vectors, so that the model has the ability to detect objects of any category, as long as the semantic vector of the corresponding category is input. + +# 3.3. Framework + +We present the framework of Meta-ZSDETR in Fig. 2, which is based on Deformable DETR. Meta-ZSDETR follows the paradigm of meta-learning. The training is performed by episode based meta-learning task. In each episode, we randomly sample an image $I$ and a class set $\mathcal{C}_{\pi}$ . The meta-learning task of each episode is to make the model learn to detect all appeared classes in $\mathcal{C}_{\pi}$ on image $I$ . Specifically, the image feature is firstly extracted by backbone and Transformer encoder as in Eq.(1). In order for the decoder to detect categories in $\mathcal{C}_{\pi}$ , we add the projected semantic vectors of classes $\mathcal{C}_{\pi}$ to the object queries, making the queries class-specific. Then, the decoder takes the queries as input and predicts the class-specific boxes directly. To achieve this, the model is optimized with meta-contrastive learning, which contains a regression head to generate the + +![](images/221136650e966e25028c4e141636cada1bb0207402e20d8f25021fa0d3ab391f.jpg) +Figure 2. The framework of Meta-ZSDETR. In each episode, a class set $\mathcal{C}_{\pi}$ and an image $I$ are sampled. The meta-learning task is to make the model learn to detect all appeared classes in $\mathcal{C}_{\pi}$ . Firstly, the image feature $x_{I}$ is extracted with backbone and encoder. Then, the projected semantic vectors are added to object queries, making them class-specific. Finally, the decoder $g_{\theta}$ will takes the queries as input and directly predict class-specific boxes. To achieve this, we train our model with proposed meta-contrastive learning. + +coordinates of class-specific boxes, a classification to predict the accuracy of generated boxes and a contrastive head that utilize the proposed contrastive-reconstruction loss to further separate different classes in visual space. + +# 3.4. Meta-ZSDETR with class-specific queries + +To enable the model to detect any unseen class, we fuse the object queries with class semantic information, and make the model learn to predict the bounding boxes for the fused classes. Such a process is carried out in each meta-learning task. + +Specifically, in each episode, we randomly sample a class set $\mathcal{C}_{\pi}$ and an image $I$ , where the $\mathcal{C}_{\pi}$ satisfies $\mathcal{C}_{\pi} \subseteq \mathcal{C}^s$ and each element is unique. Meanwhile, $\mathcal{C}_{\pi} = \mathcal{C}_{\pi}^{+} \cup \mathcal{C}_{\pi}^{-}$ , where $\mathcal{C}_{\pi}^{+}$ is the positive classes that appeared in image $I$ and $\mathcal{C}_{\pi}^{-}$ is the randomly sampled negative classes that do not appear in $I$ for contrast. Meanwhile, we denote the size of $\mathcal{C}_{\pi}$ as $L(\mathcal{C}_{\pi})$ , where $L(\cdot)$ is the operation that calculates size. The positive rate $\frac{L(\mathcal{C}_{\pi}^{+})}{L(\mathcal{C}_{\pi})}$ is set to $\lambda_{\pi}$ , which is a hyperparameter. + +Then, the corresponding semantic vectors $\mathcal{W}_{\pi}$ of class set $\mathcal{C}_{\pi}$ are projected from semantic space to the visual space with a linear layer $h_{\mathcal{W}}$ : + +$$ +\widetilde {\mathcal {W} _ {\pi}} = h _ {\mathcal {W}} \left(\mathcal {W} _ {\pi}\right) \tag {5} +$$ + +where $\widetilde{\mathcal{W}_{\pi}}$ is the projected semantic vectors of class set $\mathcal{C}_{\pi}$ . Since $L(\widetilde{\mathcal{W}_{\pi}})\ll N$ , i.e. the number of semantic vectors is smaller than the number of object queries $\mathcal{Q}$ , we expand $\widetilde{\mathcal{W}_{\pi}}$ by duplicating each element in $\widetilde{\mathcal{W}_{\pi}}$ for $T$ times, which satisfies $L(\widetilde{\mathcal{W}_{\pi}})\cdot T\geqslant N$ and $L(\widetilde{\mathcal{W}_{\pi}})\cdot (T - 1) < N$ . For redundant elements more than $N$ , we drop them. + +Then, the projected semantic vectors $\widetilde{\mathcal{W}_{\pi}}$ is added to object queries $\mathcal{Q}$ as follows: + +$$ +\mathcal {Q} _ {\pi} = \mathcal {Q} \oplus \widetilde {\mathcal {W} _ {\pi}} \tag {6} +$$ + +where $\mathcal{Q}_{\pi} = \{q_i^\pi \}_{i=1}^N$ is the class-specific queries that will be inputted into the Transformer decoder $g_{\theta}$ with image feature $x_I$ to generate predictions: + +$$ +\hat {\mathcal {Y}} = g _ {\theta} \left(x _ {I}, \mathcal {Q} _ {\pi}\right) \tag {7} +$$ + +$\hat{\mathcal{V}} = \{(\hat{\delta}_i,\hat{b}_i)\}_{i = 1}^N$ is the set of predictions, where $\hat{b}_i$ is predicted box location generated with query $q_{i}^{\pi}$ and $\hat{\delta}_i$ is the probability of box $\hat{b}_i$ belonging to the fused class, i.e. the class of semantic vector that fused to query $q_{i}^{\pi}$ . Meanwhile, different from the standard DETR that the classification head determines the class of predicted boxes, the class of predicted box $\hat{b}_i$ in Meta-ZSDETR is class-specific and is determined by the class of corresponding query and $\hat{\delta}_i$ only has one dimension to represent the probability of $\hat{b}_i$ belongs to the fused class. + +# 3.5. Meta-contrastive learning + +In order for the regression head of decoder $g_{\theta}$ to generate more accurate class-specific box coordinate $\hat{b}_i$ and classification head to have a stronger discriminative ability of further judging the location accuracy of generated $\hat{b}_i$ , we propose the meta-contrastive learning to train the heads of decoder $g_{\theta}$ , i.e. a regression head to generate class-specific boxes, a classification head to filter inaccurate boxes, and moreover a contrastive head to further separate different classes in visual space, which will improve the performance of both seen classes and unseen classes. + +Meta-contrastive learning performs the matching and optimization in a class-by-class manner. As shown in Fig. 3, for each class $c_{j}^{\pi} \in \mathcal{C}_{\pi}$ , the decoder takes queries of class $c_{j}^{\pi}$ as input, and the predictions are split into three types: 1) The positive predictions that are assigned to GT box of class $c_{j}^{\pi}$ by class-specific bipartite matching. 2) The negative predictions that are assigned to any other classes than $c_{j}^{\pi}$ . 3) The negative predictions that belong to background. + +Then, we takes different combinations of three types + +![](images/177140d1fb979f02742c666f439bf6db8b569ae17dba4a05c901c14149c88706.jpg) +Figure 3. All predictions of class $c_{j}^{\pi}$ are split into three different types and different combinations of them are utilized to train three different heads. + +of predictions to train three heads: a) For the classification head, we take all predictions for the training and give them corresponding positive/negative class-specific targets for class $c_{j}^{\pi}$ . b) For the regression head, since the regression head aims to generate class-specific boxes of class $c_{j}^{\pi}$ , we only utilize the positive predictions for optimization. c) For the contrastive head, since our intention is to separate different classes in visual space, we only use positive predictions of class $c_{j}^{\pi}$ and negative predictions of other classes for contrastive-reconstruction loss. + +# 3.5.1 Class-specific bipartite matching + +Our meta-contrastive learning performs the matching in a class-by-class manner. For class $c_{j}^{\pi} \in \mathcal{C}_{\pi}$ , the predictions generated by queries of class $c_{j}^{\pi}$ are selected for bipartite matching, which is denoted as $\hat{\mathcal{Y}}_{c_j^\pi} = \{(\hat{\delta}_{\tau_i},\hat{b}_{\tau_i})\}_{i = 1}^{T_\tau}$ where $\{\tau_i\}_{i = 1}^{T_\tau}$ are the indexes for queries of class $c_{j}^{\pi}$ in $N$ queries. Since each query is duplicated for $T$ or $T - 1$ times, we denote the length uniformly as $T_{\tau}$ . + +Then, the ground-truth matching targets are revised for each class $c_{j}^{\pi}\in \mathcal{C}_{\pi}$ . The class-specific matching labels are denoted as $\Delta_{c_j^\pi} = \{\delta_i^{c_j^\pi}\}_{i = 1}^{T_\tau}$ (padded with no objects $\varnothing$ ), which satisfy: + +$$ +\delta_ {i} ^ {c _ {j} ^ {\pi}} = \left\{ \begin{array}{l l} 1, & c _ {i} = c _ {j} ^ {\pi} \\ 0, & c _ {i} \neq c _ {j} ^ {\pi} \end{array} \right. \tag {8} +$$ + +where $c_{i}$ is the origin class label for ground-truth box $b_{i}$ . The revised matching labels are generated according to whether $c_{i}$ is equal to $c_{j}^{\pi}$ . Then, the matching targets $\mathcal{Y}_{c_j^\pi} = \{(\delta_i^{c_j^\pi}, b_i)\}_{i=1}^{T_\tau}$ is utilized for bipartite matching of class $c_{j}^{\pi}$ , where a permutation of $T_{\tau}$ elements $\sigma \in \mathfrak{S}_{T_{\tau}}$ with lowest cost is search as: + +$$ +\hat {\sigma} = \underset {\sigma \in \mathfrak {S} _ {T \tau}} {\arg \min } \sum_ {i = 1} ^ {T _ {\tau}} \left[ \mathcal {L} _ {c l s} (\delta_ {i} ^ {e _ {j} ^ {\pi}}, \hat {\delta} _ {\tau_ {\sigma_ {i}}}) + \mathcal {L} _ {l o c} (b _ {i}, \hat {b} _ {\tau_ {\sigma_ {i}}}) \right] \tag {9} +$$ + +where $\hat{\sigma}$ is the optimal assignment between matching targets $\mathcal{V}_{c_j^\pi}$ and predictions $\hat{\mathcal{V}}_{c_j^\pi}$ . $\mathcal{L}_{cls}$ and $\mathcal{L}_{loc}$ are the same as that in Eq.(3). + +# 3.5.2 Loss function + +Based on $\hat{\sigma}$ , predictions in $\hat{Y}_{c_j^\pi}$ are split into three types mentioned above, i.e. positive and two types of negative ones, and loss function of class $c_{j}^{\pi}$ for three heads are calculated as follows: + +$$ +\mathcal {L} _ {c _ {j} ^ {\pi}} = \sum_ {i = 1} ^ {T _ {\tau}} \left[ \mathcal {L} _ {c l s} \left(\delta_ {i} ^ {c _ {j} ^ {\pi}}, \hat {\delta} _ {\tau_ {\hat {\sigma} _ {i}}}\right) + \mathbb {1} _ {\left(c _ {i} = c _ {j} ^ {\pi}\right)} \mathcal {L} _ {l o c} \left(b _ {i}, \hat {b} _ {\tau_ {\hat {\sigma} _ {i}}}\right) \right] + \mathcal {L} _ {c o n t} \tag {10} +$$ + +where the loss $\mathcal{L}_{c_j^\pi}$ for class $c_{j}^{\pi}$ is composed of classification loss $\mathcal{L}_{cls}$ , regression loss $\mathcal{L}_{loc}$ and contrastive-reconstruction loss $\mathcal{L}_{cont}$ . + +Classification loss. $\mathcal{L}_{cls}$ takes all predictions as input and makes the model learn to distinguish whether a predicted box belongs to $c_{j}^{\pi}$ . The predicted box has the label $\delta_{i}^{c_{j}^{\pi}} = 1$ if and only if it is assigned to a ground-truth box with class label $c_{j}^{\pi}$ . We implement $\mathcal{L}_{cls}$ with focal loss [23]. + +Regression loss. Since our intention is to generate class-specific boxes, i.e. input decoder with query of class $c_{j}^{\pi}$ and output box of class $c_{j}^{\pi}$ , we only select the ground-truth box with class label $c_{j}^{\pi}$ for optimization, i.e. $\delta_{i}^{c_{j}^{\pi}} = 1$ , making the predicted boxes to be closer to GT boxes with class label $c_{j}^{\pi}$ . The $\mathcal{L}_{loc}$ is implemented with $l_{1}$ loss and GIoU loss [35]. + +Contrastive-reconstruction loss. In ZSD tasks, the original visual space is not well-structured due to the lack of discriminative information, many previous works solved it by introducing a reconstruction loss to guide the distribution of visual features. Here, we combine the reconstruction loss and contrastive loss to bring a higher intra-class compactness and inter-class separability of the visual structure. + +In particular, we project the last hidden features of decoder to the semantic space, where the projected hidden features of positive predictions are constraint to be as close as possible to $\omega_{j}^{\pi}$ , which is the semantic vector of class $c_{j}^{\pi}$ and the negative ones are constraint to be as far as possible to $\omega_{j}^{\pi}$ . Formally, we denote the last hidden feature of optimal box $(\hat{\delta}_{\tau_{\hat{\sigma}_i}},\hat{b}_{\tau_{\hat{\sigma}_i}})$ that matched to GT box $(c_i,b_i)$ as $z_{\tau_{\hat{\sigma}_k}}$ and the $\mathcal{L}_{cont}$ is formulated as: + +$$ +\mathcal {L} _ {\text {c o n t}} = \frac {1}{N _ {\text {p o s}}} \sum_ {i = 1} ^ {T _ {\tau}} \mathbb {1} _ {\left(c _ {i} = c _ {j} ^ {\pi}\right)} \mathcal {L} _ {\text {c o n t}} \left(z _ {\tau_ {\hat {\sigma} _ {i}}}\right) \tag {11} +$$ + +$$ +\mathcal {L} _ {\text {c o n t}} \left(z _ {\tau_ {\hat {\sigma} _ {i}}}\right) = - \log \frac {\exp \left[ h _ {\rho} \left(z _ {\tau_ {\hat {\sigma} _ {i}}}\right) \cdot \omega_ {j} ^ {\pi} / \kappa \right]}{\sum_ {k = 1} ^ {T _ {\tau}} \mathbb {1} _ {(c _ {k} \neq \varnothing)} \exp \left[ h _ {\rho} \left(z _ {\tau_ {\hat {\sigma} _ {k}}}\right) \cdot \omega_ {j} ^ {\pi} / \kappa \right]} \tag {12} +$$ + +where $h_{\rho}$ is a linear layer that projects the hidden feature to the semantic space. $N_{pos}$ is the number of positive predictions of class $c_{j}^{\pi}$ . $\kappa$ is a temperature hyper-parameter + +as in InfoNCE [28]. The optimization of the above loss function increases the instance-level similarity between projected hidden features of positive predictions with semantic vector $\omega_{j}^{\pi}$ and space the negative ones. As a result, visual features of the same class will form a tighter cluster. + +Total loss function. We compute the loss function with Eq.(10) for each class $c_{j}^{\pi} \in \mathcal{C}_{\pi}$ , separately. For negative classes $\mathcal{C}_{\pi}^{-}$ , only classification loss is calculated. Finally, the loss of current episode is averaged over all classes in sampled class set $\mathcal{C}_{\pi}$ : + +$$ +\mathcal {L} = \frac {1}{L \left(\mathcal {C} _ {\pi}\right)} \sum_ {j = 1} ^ {L \left(\mathcal {C} _ {\pi}\right)} \mathcal {L} _ {c _ {j} ^ {\pi}} \tag {13} +$$ + +where $L(\mathcal{C}_{\pi})$ is the number of classes in $\mathcal{C}_{\pi}$ . We utilize $\mathcal{L}$ for model optimization. + +# 4. Experiments + +# 4.1. Datasets and splits + +Following previous works [40, 17], we takes two benchmark datasets for evaluation: PASCAL VOC 2007+2012 [9] and MS COCO 2014 [24]. + +Datasets: PASCAL VOC contains 20 classes of objects for object detection. More specifically, the PASCAL VOC 2,007 is composed of 2,501 training images, 2,510 validation images, and 5,011 test images. The PASCAL VOC 2012 dataset comprises 5,717 training images and 5,823 validation images, without test images released. MS COCO 2014 is a benchmark dataset designed for object detection and semantic segmentation tasks, which contains 82,783 training and 40,504 validation images from 80 categories. For PASCAL VOC and MS COCO, we adopt the Fast-Text [26] to extract the semantic vectors following [14, 17]. + +Seen/unseen splits: All splits follow the previous setting [40, 17]. For PASCAL VOC, we use a 16/4 split proposed in [7]. For MS COCO, we follow the same procedures described in [2, 29, 17] to take 2 different splits, i.e. 48/17 and 65/15. For all datasets, the images that contain unseen classes in the training set are removed to guarantee that unseen objects will not be available during training. + +# 4.2. Evaluation protocols + +We adopt the widely-used evaluation protocols proposed in [2, 7]. For PASCAL VOC, mAP with IoU threshold 0.5 is used to evaluate the performance. For MS COCO, mAP and recall@100 with three different IoU threshold (i.e. 0.4, 0.5 and 0.6) are utilized for evaluation. For GZSD setting that contains both seen and unseen classes, the performance is evaluated by Harmonic Mean (HM). + +# 4.3. Implementation details + +We build Meta-ZSDETR on Deformable DETR [48] with ResNet-50 [16] as backbone. The number of queries + +
MethodZSDGZSD
SUHM
SAN [31]59.148.037.041.8
HRE [8]54.262.425.536.2
PL [30]62.1---
BLC [45]55.258.222.932.9
SU [15]64.9---
Robust-Syn [17]65.547.149.148.1
ContrastZSD [40]65.763.246.553.6
Meta-ZSDETR70.367.656.361.4
+ +Table 1. The results of mAP in PASCAL VOC with IoU=0.5 under ZSD and GZSD settings. Here, "S" denotes seen classes, "U" denotes unseen classes and "HM" denotes harmonic mean. + +
MethodcardogsofatrainmAP
SAN [31]56.285.362.626.457.6
HRE [8]55.082.055.026.054.5
PL [30]63.787.253.244.162.1
BLC [45]43.78660.830.155.2
SU [15]59.692.762.345.264.9
Robust-Syn [17]60.193.059.749.165.5
ContrastZSD [40]65.586.463.147.965.7
Meta-ZSDETR69.092.465.754.170.3
+ +Table 2. Class-wise AP and mAP on unseen classes in PASCAL VOC under ZSD setting. + +$N$ is set to 900. For the sampled class set $\mathcal{C}_{\pi}$ , the positive classes consist of the classes that appear in the image and the negative classes is sampled from $\mathcal{C}^s$ . The positive rate $\lambda_{\pi}$ is set to 0.5. The number of Transformer encoder layers and decoder layers is set to 6. The temperature hyperparameter $\kappa$ in Eq.(12) is set to 0.2. We train our model for total 500,000 iterations with batch size 16, i.e. each iteration contains 16 episodes in parallel. Following Deformable DETR, different coefficients are utilized to weight different loss functions, where 1.0 is used for classification loss, 5.0 is used for $l_1$ loss of regression head, 2.0 is used for GIoU loss of regression head and 1.0 is used for contrastive-reconstruction loss. More details can refer to our code. + +# 4.4. Comparison with existing methods + +# 4.4.1 PASCAL VOC + +We present the results of PASCAL VOC in Tab. 1, where we can see that our method performs best among all existing methods under both ZSD and GZSD settings, and lift the mAP in PASCAL VOC to a higher level. + +Specifically, in ZSD setting, Meta-ZSDETR achieves 70.3 mAP and outperform the second-best model ContrastZSD [40] by a large margin of 4.6 mAP, which is the + +
MethodSplitRecall@100mAP
IoU=0.4IoU=0.5IoU=0.6IoU=0.5
DSES [3]48/1740.227.213.60.5
TD [22]48/1745.534.318.1-
PL [30]48/17-43.5-10.1
BLC [45]48/1751.348.845.010.6
ZSDTR [43]48/1751.848.544.510.4
Robust-Syn [17]48/1758.153.547.913.4
ContrastZSD [40]48/1756.152.447.212.5
Meta-ZSDETR48/1762.359.854.215.1
PL [30]65/15-37.7-12.4
BLC [45]65/1557.254.751.214.7
SU [15]65/1554.454.047.019.0
ZSDTR [43]65/1563.860.356.513.2
Robust-Syn [17]65/1565.362.355.919.8
ContrastZSD [40]65/1562.359.555.118.6
Meta-ZSDETR65/1569.166.759.022.5
+ +Table 3. ZSD performance of Recall@100 and mAP with different IoU thresholds on MS COCO dataset. + +first time to boost the performance of ZSD setting on PASCAL VOC to over $70\mathrm{mAP}$ . + +For GZSD setting, our method also achieves SOTAs in all three metrics, i.e. mAP on seen classes, unseen classes and harmonic mean, which brings about 4.4, 9.8 and 7.8 points improvement, respectively. It is worth noting that the improvement of our method on unseen classes in GZSD setting is extremely large, which proves that our method has a strong generalization on unseen classes, and can alleviate the problem that the unseen classes tend to be misclassified into seen classes to a certain extent. We also report class-wise mAP in ZSD setting in Tab. 2, where our method achieves the best performance on 3 classes. + +# 4.4.2 MS COCO + +We perform experiments on MS COCO, where the results of ZSD setting is shown in Tab. 3 and the results of GZSD setting is shown in Tab. 4. We can see that Meta-ZSDETR achieves the best results in all metrics under all settings. + +For ZSD setting, we can see that mAP of our method in 48/17 and 65/15 splits outperforms the second-best by a margin of 1.7 and $2.7\mathrm{mAP}$ , respectively, which demonstrates that our method generalizes well to unseen classes. Meanwhile, we can see that Recall@100 decrease as the IoU increases in all methods. Compared with other methods, Meta-ZSDETR has a smaller drop, which is benefit from that our decoder can generate more accurate boxes with class semantic information as input. + +For GZSD setting, our method achieves SOTAs in both seen and unseen classes. The harmonic means of mAP un + +
MethodSplitRecall@100mAP
SUHMSUHM
PL [30]48/1738.226.331.235.94.17.4
BLC [45]48/1757.646.451.442.14.58.2
ZSDTR [43]48/1774.348.460.548.55.69.5
Robust-Syn [17]48/1759.758.859.242.313.420.4
ContrastZSD [40]48/1765.752.458.345.16.311.1
Meta-ZSDETR48/1774.359.065.848.714.622.5
PL [30]65/1536.437.236.834.112.418.2
BLC [45]65/1556.451.753.936.013.119.2
SU [15]65/1557.753.955.836.919.025.1
ZSDTR [43]65/1569.159.561.140.613.220.2
Robust-Syn [17]65/1558.661.860.237.419.826.0
ContrastZSD [40]65/1562.958.660.740.216.523.4
Meta-ZSDETR65/1571.165.468.145.921.729.5
+ +Table 4. GZSD performance of Recall@100 and mAP with IoU=0.5 on MS COCO dataset. + +
LocClsContSeenUnseen
✓39.914.5
✓✓44.820.6
✓✓40.615.3
✓✓✓45.921.7
+ +Table 5. Ablation study of different combinations of loss functions. + +der 48/17 and 65/15 splits are improved from 20.4 to 22.5, and from 26.0 to 29.5, demonstrating the effectiveness and superiority of our method. Meanwhile, the Recall@100 also improves due to the powerful class-specific boxes generation capabilities. We also report the class-wise AP in 65/15 split of MS COCO, which can be found in our supplementary material. + +# 4.5. Ablation study + +We analyze the effects of various components in Meta-ZSDETR. Unless otherwise specified, the experiments are carried out on MS COCO with 65/15 split under GZSD setting and use mAP with IoU=0.5 as metric. + +Effects of different loss functions. Here, we analyze the effects of three loss functions in meta-contrastive learning. We utilize different combinations of regression loss $\mathcal{L}_{loc}$ , classification loss $\mathcal{L}_{cls}$ and contrastive-reconstruction loss $\mathcal{L}_{cont}$ to optimize the model, and show the results in Tab. 5. Since the regression loss is necessary, we keep it for all combinations. For model without classification loss $\mathcal{L}_{cls}$ , we do not perform the boxes filter and directly use the class-specific boxes predicted from regression head, where the scores are generated randomly. As we can see, if the model is only trained with regression head to gen + +
Heads\( \hat{y}_{pos} \)\( \hat{y}_{other} \)\( \hat{y}_{bg} \)SeenUnseen
Classification Head✓✓43.717.9
✓✓44.819.0
✓✓✓45.921.7
Regression Head✓45.921.7
✓✓42.116.5
Contrastive Head✓45.121.0
✓✓45.921.7
✓✓✓45.421.3
+ +Table 6. Ablation study on using different combinations of predictions to train three heads. + +erate class-specific boxes, it can achieve a mAP of 14.5 in unseen classes, which is relatively low, but also surpasses many previous methods. Adding the classification loss will greatly boost the performance of unseen classes to $20.6\mathrm{mAP}$ , which thanks to the powerful discriminative ability of the classification head that can filter inaccurate boxes. Meanwhile, the contrastive-reconstruction loss can improve the performance with and without the classification head about 1 point. Finally, the combination of three losses achieves the best performance. + +Study for training of different heads. As describe, based on the class-specific bipartite matching for class $c_{j}^{\pi}$ , all predictions are split into three different types: the positive predictions $\hat{Y}_{pos}$ assigned to GT boxes of $c_{j}^{\pi}$ , the negative predictions $\hat{Y}_{other}$ assigned to other classes and the negative predictions $\hat{Y}_{bg}$ that belong to background. Here, we study different combinations of them to train three heads and the results are shown in Tab. 6. We can see that: 1) For classification head, since it aims to filter all kinds of negative predictions, using all predictions to train it can achieve the best performance. 2) For regression head, if we train it with GT boxes of all classes, i.e. using $\hat{Y}_{pos}$ and $\hat{Y}_{other}$ , the regression head will degenerate into a class-agnostic RPN, which will greatly reduce the recall of unseen classes, thus lead to a lower mAP. 3) For contrastive head, on one hand, if we only use $\hat{Y}_{pos}$ for training, it will degenerate into a reconstruction loss, which has been widely used in previous works and it will bring a 0.4 mAP improvement in unseen classes compared with the version without it. On the other hand, compared with using all predictions, removing background predictions will make the contrastive head focus on distinguishing $\hat{Y}_{other}$ and inputed semantic vectors of class $c_{j}^{\pi}$ , thus brings more improvement. + +Visualization for contrastive-reconstruction loss. Here, we study the influence of contrastive-reconstruction loss on visual space by visualizing the distribution of hidden features with t-SNE. We visualize the last hidden features of decoder in unseen classes of PASCAL VOC. The result is shown in Fig. 4. As we can see, our contrastive + +![](images/82eafe7a1ae372f9a1ec5a0c2466cc28ad5ee6521d163acf4375d75c75fd4203.jpg) +Figure 4. The t-SNE visualization of the last hidden layer of decoder. We can see that the contrastive head can separate different classes in visual space. + +![](images/e0c24144bb6a945924f28443a81db028ce76c24751dc526ed9e377bc10b8566b.jpg) + +![](images/ec9805989e4ed217a78e22449565b12739f81500cbf5ffd6ce8dfbb33f02af2d.jpg) +Figure 5. The effect of number of queries and positive rate of $C_{\pi}$ + +reconstruction loss can further separate different classes in visual space and bring a higher intra-class compactness and inter-class separability of the visual structure. + +Effect of number of queries and positive rate. We study the effect of number of queries $N$ and positive rate $\lambda_{\pi}$ of sampled class set $C_{\pi}$ . We found that $\lambda_{\pi}$ have different influence under different number of queries $N$ . We change the positive rate $\lambda_{\pi}$ in different settings of $N$ and report the mAP of converged model in unseen classes. In each episode, we control $\lambda_{\pi}$ by sampling different number of negative classes. All models are trained for 500,000 episodes. The results are shown in Fig. 5. As we can see, a larger $N$ tends to have a better performance due to a higher recall, and of course a higher amount of calculation. Meanwhile, when $N$ is small (e.g. 100), a small positive rate will greatly reduce the amount of positive queries for training, thereby reducing the model performance. When $N$ is large (e.g. 900), the number of positive queries is guaranteed and more negative queries are needed for the classification head to learn to distinguish among them. Therefore, we can see the best performance is achieved when $\lambda_{\pi}$ is 0.5 and $N$ is 900. + +# 5. Conclusion + +In this paper, we present the first work that combine DETR and meta-learning to perform zero-shot object detection, which formalize the training as individual episode + +based meta-learning task. In each episode, we randomly sample an image and a class set. The meta-learning task is to make the model learn to detect all appeared classes of the sampled class set on the image. To achieve this, we train the decoder to directly predict class-specific boxes with class-specific queries as input, under the supervision of our meta-contrastive learning that contains three different heads. We conduct extensive experiments on the benchmark datasets MSCOCO and PASCAL VOC. Experimental results show that our method outperforms the existing ZSD methods. In the future, we will focus on further performance improvement. + +Acknowledgement. Jihong Guan was supported by National Natural Science Foundation of China (NSFC) under grant No. U1936205. + +# References + +[1] Zeynep Akata, Florent Perronnin, Zaid Harchaoui, and Cordelia Schmid. Label-embedding for attribute-based classification. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 819–826, 2013. 2 +[2] Ankan Bansal, Karan Sikka, Gaurav Sharma, Rama Chellappa, and Ajay Divakaran. Zero-shot object detection. In Proceedings of the European Conference on Computer Vision (ECCV), pages 384-400, 2018. 1, 2, 6 +[3] Ankan Bansal, Karan Sikka, Gaurav Sharma, Rama Chellappa, and Ajay Divakaran. Zero-shot object detection. In ECCV, pages 384-400, 2018. 7 +[4] Maxime Bucher, Stéphane Herbin, and Frédéric Jurie. Improving semantic embedding consistency by metric learning for zero-shot classification. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part V 14, pages 730-746. Springer, 2016. 2 +[5] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part I 16, pages 213-229. Springer, 2020. 2 +[6] Shiming Chen, Wenjie Wang, Beihao Xia, Qinmu Peng, Xinge You, Feng Zheng, and Ling Shao. Free: Feature refinement for generalized zero-shot learning. In Proceedings of the IEEE/CVF international conference on computer vision, pages 122-131, 2021. 2 +[7] Berkan Demirel, Ramazan Gokberk Cinbis, and Nazli Ikizler-Cinbis. Zero-shot object detection by hybrid region embedding. arXiv preprint arXiv:1805.06157, 2018. 1, 2, 6 +[8] Berkan Demirel, Ramazan Gokberk Cinbis, and Nazli Ikizler-Cinbis. Zero-shot object detection by hybrid region embedding. In BMVC, 2018. 6 +[9] Mark Everingham, Luc Van Gool, Christopher KI Williams, John Winn, and Andrew Zisserman. The pascal visual object classes (voc) challenge. International journal of computer vision, 88:303-308, 2009. 6 + +[10] Yanwei Fu, Timothy M Hospedales, Tao Xiang, Zhenyong Fu, and Shaogang Gong. Transductive multi-view embedding for zero-shot recognition and annotation. In Computer Vision-ECCV 2014: 13th European Conference, Zurich, Switzerland, September 6-12, 2014, Proceedings, Part II 13, pages 584-599. Springer, 2014. 2 +[11] Ross Girshick. Fast r-cnn. In Proceedings of the IEEE international conference on computer vision, pages 1440-1448, 2015. 2 +[12] Dikshant Gupta, Aditya Anantharaman, Nehal Mamgain, Vineeth N Balasubramanian, CV Jawahar, et al. A multi-space approach to zero-shot object detection. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1209-1217, 2020. 1, 2 +[13] Zongyan Han, Zhenyong Fu, and Jian Yang. Learning the redundancy-free features for generalized zero-shot object recognition. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 12865-12874, 2020. 2 +[14] Nasir Hayat, Munawar Hayat, Shafin Rahman, Salman Khan, Syed Waqas Zamir, and Fahad Shahbaz Khan. Synthesizing the unseen for zero-shot object detection. In Proceedings of the Asian Conference on Computer Vision, 2020. 1, 2, 6 +[15] Nasir Hayat, Munawar Hayat, Shafin Rahman, Salman Khan, Syed Waqas Zamir, and Fahad Shahbaz Khan. Synthesizing the unseen for zero-shot object detection. In ACCV, 2020. 6, 7 +[16] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 6 +[17] Peiliang Huang, Junwei Han, De Cheng, and Dingwen Zhang. Robust region feature synthesizer for zero-shot object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7622-7631, 2022. 1, 2, 6, 7 +[18] Siddhesh Khandelwal, Anirudth Nambirajan, Behjat Siddique, Jayan Eledath, and Leonid Sigal. Frustratingly simple but effective zero-shot detection and segmentation: Analysis and a strong baseline. arXiv preprint arXiv:2302.07319, 2023. 1, 2 +[19] Dahun Kim, Tsung-Yi Lin, Anelia Angelova, In So Kweon, and Weicheng Kuo. Learning open-world object proposals without learning to classify. IEEE Robotics and Automation Letters, 7(2):5453-5460, 2022. 1 +[20] Diederik P Kingma and Max Welling. Auto-encoding variational bayes. arXiv preprint arXiv:1312.6114, 2013. 2 +[21] Elyor Kodirov, Tao Xiang, and Shaogang Gong. Semantic autoencoder for zero-shot learning. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3174-3183, 2017. 2 +[22] Zhihui Li, Lina Yao, Xiaoqin Zhang, Xianzhi Wang, Salil Kanhere, and Huaxiang Zhang. Zero-shot object detection with textual descriptions. In AAAI, volume 33, pages 8690-8697, 2019. 7 + +[23] Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dólár. Focal loss for dense object detection. In Proceedings of the IEEE international conference on computer vision, pages 2980-2988, 2017. 2, 3, 5 +[24] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólár, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In Computer Vision-ECCV 2014: 13th European Conference, Zurich, Switzerland, September 6-12, 2014, Proceedings, Part V 13, pages 740-755. Springer, 2014. 6 +[25] Qiaomei Mao, Chong Wang, Shenghao Yu, Ye Zheng, and Yuqi Li. Zero-shot object detection with attributes-based category similarity. IEEE Transactions on Circuits and Systems II: Express Briefs, 67(5):921-925, 2020. 1, 2 +[26] Tomas Mikolov, Edouard Grave, Piotr Bojanowski, Christian Puhrsch, and Armand Joulin. Advances in pretraining distributed word representations. arXiv preprint arXiv:1712.09405, 2017. 6 +[27] Sanath Narayan, Akshita Gupta, Fahad Shahbaz Khan, Cees GM Snoek, and Ling Shao. Latent embedding feedback and discriminative features for zero-shot classification. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XXII 16, pages 479-495. Springer, 2020. 1, 2 +[28] Aaron van den Oord, Yazhe Li, and Oriol Vinyals. Representation learning with contrastive predictive coding. arXiv preprint arXiv:1807.03748, 2018. 6 +[29] Shafin Rahman, Salman Khan, and Nick Barnes. Improved visual-semantic alignment for zero-shot object detection. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 11932–11939, 2020. 6 +[30] Shafin Rahman, Salman Khan, and Nick Barnes. Improved visual-semantic alignment for zero-shot object detection. In AAAI, volume 34, pages 11932–11939, 2020. 6, 7 +[31] Shafin Rahman, Salman Khan, and Fatih Porikli. Zero-shot object detection: Learning to simultaneously recognize and localize novel concepts. In ACCV, pages 547-563. Springer, 2018. 6 +[32] Shafin Rahman, Salman H Khan, and Fatih Porikli. Zero-shot object detection: Joint recognition and localization of novel concepts. International Journal of Computer Vision, 128:2979-2999, 2020. 1, 2 +[33] Joseph Redmon, Santosh Divvala, Ross Girshick, and Ali Farhadi. You only look once: Unified, real-time object detection. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 779-788, 2016. 2 +[34] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. In NIPS, 2015. 1 +[35] Hamid Rezatofighi, Nathan Tsoi, JunYoung Gwak, Amir Sadeghian, Ian Reid, and Silvio Savarese. Generalized intersection over union: A metric and a loss for bounding box regression. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 658-666, 2019. 3, 5 +[36] Edgar Schonfeld, Sayna Ebrahimi, Samarth Sinha, Trevor Darrell, and Zeynep Akata. Generalized zero-and few-shot + +learning via aligned variational autoencoders. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8247-8255, 2019. 2 +[37] Flood Sung, Yongxin Yang, Li Zhang, Tao Xiang, Philip HS Torr, and Timothy M Hospedales. Learning to compare: Relation network for few-shot learning. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1199-1208, 2018. 2 +[38] Yongqin Xian, Tobias Lorenz, Bernt Schiele, and Zeynep Akata. Feature generating networks for zero-shot learning. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5542-5551, 2018. 2 +[39] Yongqin Xian, Saurabh Sharma, Bernt Schiele, and Zeynep Akata. f-vaegan-d2: A feature generating framework for any-shot learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 10275–10284, 2019. 2 +[40] Caixia Yan, Xiaojun Chang, Minnan Luo, Huan Liu, Xiaoqin Zhang, and Qinghua Zheng. Semantics-guided contrastive network for zero-shot object detection. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 1, 2, 6, 7 +[41] Caixia Yan, Qinghua Zheng, Xiaojun Chang, Minnan Luo, Chung-Hsing Yeh, and Alexander G Hauptman. Semantics-preserving graph propagation for zero-shot object detection. IEEE Transactions on Image Processing, 29:8163-8176, 2020. 1, 2 +[42] Shizhen Zhao, Changxin Gao, Yuanjie Shao, Lerenhan Li, Changqian Yu, Zhong Ji, and Nong Sang. Gtnet: Generative transfer network for zero-shot object detection. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 12967-12974, 2020. 1, 2 +[43] Ye Zheng and Li Cui. Zero-shot object detection with transformers. In 2021 IEEE International Conference on Image Processing (ICIP), pages 444-448. IEEE, 2021. 2, 7 +[44] Ye Zheng, Ruoran Huang, Chuanqi Han, Xi Huang, and Li Cui. Background learnable cascade for zero-shot object detection. In Proceedings of the Asian Conference on Computer Vision, 2020. 1, 2 +[45] Ye Zheng, Ruoran Huang, Chuanqi Han, Xi Huang, and Li Cui. Background learnable cascade for zero-shot object detection. In ACCV, 2020. 6, 7 +[46] Ye Zheng, Jiahong Wu, Yongqiang Qin, Faen Zhang, and Li Cui. Zero-shot instance segmentation. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2593-2602, 2021. 2 +[47] Pengkai Zhu, Hanxiao Wang, and Venkatesh Saligrama. Don't even look once: Synthesizing features for zero-shot detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11693-11702, 2020. 1, 2 +[48] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable $\{\mathrm{detr}\}$ : Deformable transformers for end-to-end object detection. In International Conference on Learning Representations, 2021. 2, 6 \ No newline at end of file diff --git a/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/images.zip b/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..2484da416d29e544e76237e26764b4aab574a708 --- /dev/null +++ b/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:9fdde5fc27fc23fa3b22b7ca4eca629c56d1cc032c8247153c0920fb8744ea2a +size 492334 diff --git a/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/layout.json b/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..17891ce0a3043cdc5227a1040c19a22093b2d88e --- /dev/null +++ b/2023/Meta-ZSDETR_ Zero-shot DETR with Meta-learning/layout.json @@ -0,0 +1,11524 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 132, + 103, + 463, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 132, + 103, + 463, + 121 + ], + "spans": [ + { + "bbox": [ + 132, + 103, + 463, + 121 + ], + "type": "text", + "content": "Meta-ZSDETR: Zero-shot DETR with Meta-learning" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 100, + 142, + 496, + 157 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 100, + 142, + 496, + 157 + ], + "spans": [ + { + "bbox": [ + 100, + 142, + 496, + 157 + ], + "type": "text", + "content": "Lu Zhang1 Chenbo Zhang1 Jiajia Zhao2 Jihong Guan3 Shuigeng Zhou1*" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 123, + 157, + 471, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 123, + 157, + 471, + 185 + ], + "spans": [ + { + "bbox": [ + 123, + 157, + 471, + 185 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 123, + 157, + 471, + 185 + ], + "type": "text", + "content": "Shanghai Key Lab of Intelligent Information Processing, and School of Computer Science, Fudan University, China" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 155, + 185, + 438, + 213 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 155, + 185, + 438, + 213 + ], + "spans": [ + { + "bbox": [ + 155, + 185, + 438, + 213 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 155, + 185, + 438, + 213 + ], + "type": "text", + "content": "Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory, China" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 115, + 213, + 478, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 115, + 213, + 478, + 228 + ], + "spans": [ + { + "bbox": [ + 115, + 213, + 478, + 228 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 115, + 213, + 478, + 228 + ], + "type": "text", + "content": "Department of Computer Science & Technology, Tongji University, China" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 141, + 229, + 447, + 241 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 141, + 229, + 447, + 241 + ], + "spans": [ + { + "bbox": [ + 141, + 229, + 447, + 241 + ], + "type": "text", + "content": "{1_zhang19,sgzhou}@fudan.edu.cn,cbzhang21@m.fudan.edu.cn" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 171, + 243, + 422, + 255 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 171, + 243, + 422, + 255 + ], + "spans": [ + { + "bbox": [ + 171, + 243, + 422, + 255 + ], + "type": "text", + "content": "zhaojiajial982@gmail.com, jhguan@tongji.edu.cn" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 143, + 282, + 192, + 295 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 282, + 192, + 295 + ], + "spans": [ + { + "bbox": [ + 143, + 282, + 192, + 295 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 308, + 290, + 584 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 308, + 290, + 584 + ], + "spans": [ + { + "bbox": [ + 46, + 308, + 290, + 584 + ], + "type": "text", + "content": "Zero-shot object detection aims to localize and recognize objects of unseen classes. Most of existing works face two problems: the low recall of RPN in unseen classes and the confusion of unseen classes with background. In this paper, we present the first method that combines DETR and meta-learning to perform zero-shot object detection, named Meta-ZSDETR, where model training is formalized as an individual episode based meta-learning task. Different from Faster R-CNN based methods that firstly generate class-agnostic proposals, and then classify them with visual-semantic alignment module, Meta-ZSDETR directly predict class-specific boxes with class-specific queries and further filter them with the predicted accuracy from classification head. The model is optimized with meta-contrastive learning, which contains a regression head to generate the coordinates of class-specific boxes, a classification head to predict the accuracy of generated boxes, and a contrastive head that utilizes the proposed contrastive-reconstruction loss to further separate different classes in visual space. We conduct extensive experiments on two benchmark datasets MS COCO and PASCAL VOC. Experimental results show that our method outperforms the existing ZSD methods by a large margin." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 604, + 128, + 617 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 604, + 128, + 617 + ], + "spans": [ + { + "bbox": [ + 47, + 604, + 128, + 617 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 624, + 288, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 624, + 288, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 624, + 288, + 696 + ], + "type": "text", + "content": "Object detection [34] is one of the most fundamental tasks in computer vision. Most existing object detection methods require huge amounts of annotated training data, which is expensive and time-consuming to acquire. Meanwhile, in reality novel categories constantly emerge, and there is seriously lack or even nonexistent of visual data of" + } + ] + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 306, + 283, + 547, + 339 + ], + "blocks": [ + { + "bbox": [ + 306, + 283, + 547, + 339 + ], + "lines": [ + { + "bbox": [ + 306, + 283, + 547, + 339 + ], + "spans": [ + { + "bbox": [ + 306, + 283, + 547, + 339 + ], + "type": "image", + "image_path": "ccbc76cd1200013161c58b7b3c7df57dd1e2ae33624a33d52aee5575bfb2bd69.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 306, + 341, + 547, + 399 + ], + "blocks": [ + { + "bbox": [ + 306, + 341, + 547, + 399 + ], + "lines": [ + { + "bbox": [ + 306, + 341, + 547, + 399 + ], + "spans": [ + { + "bbox": [ + 306, + 341, + 547, + 399 + ], + "type": "image", + "image_path": "aafd1f74639b77112c331511209b22ff7d4d38d1cb4c2f1dcf971d11041e4343.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 411, + 547, + 477 + ], + "lines": [ + { + "bbox": [ + 305, + 411, + 547, + 477 + ], + "spans": [ + { + "bbox": [ + 305, + 411, + 547, + 477 + ], + "type": "text", + "content": "Figure 1. Zero-shot object detection: Faster R-CNN based methods vs. Meta-ZSDETR. (a): Faster R-CNN based methods firstly generate class-agnostic proposals, and then classify them with different visual-semantic alignment modules. (b): Meta-ZSDETR directly predict class-specific boxes with class-specific queries and further filter them with classification head." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 496, + 546, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 496, + 546, + 544 + ], + "spans": [ + { + "bbox": [ + 304, + 496, + 546, + 544 + ], + "type": "text", + "content": "those novel categories for model training, such as endangered species in the wild. The above issues motivate the investigation of zero-shot object detection, which aims to localize and recognize objects of unseen classes." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 545, + 547, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 545, + 547, + 640 + ], + "spans": [ + { + "bbox": [ + 304, + 545, + 547, + 640 + ], + "type": "text", + "content": "A mainstream framework of the existing works that are based on Faster R-CNN, is illustrated in Fig. 1(a), where the RPN remains unchanged and the RoI classification head is replaced with different visual-semantic alignment modules, such as mapping to the same embedding space to calculate similarity between proposals and semantic vectors [2, 40, 41, 32, 44, 12, 25, 18, 7], synthesizing visual features from semantic vectors [17, 14, 42, 47, 27] etc." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 642, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 547, + 713 + ], + "type": "text", + "content": "However, we observe that the existing methods are suboptimal, due to their obvious inherent shortcomings: i) The proposals from RPN are often not reliable enough to cover all unseen classes objects in an image because of lacking training data, which has also been identified by a recent study [19]. ii) The confusion between background and un" + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 703, + 137, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 703, + 137, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 703, + 137, + 712 + ], + "type": "text", + "content": "* correspondence author" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6845" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 108 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 108 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 108 + ], + "type": "text", + "content": "seen classes is an intractable problem. Although many previous works have tried to tackle it [46, 14, 2], the results are still unsatisfactory." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 110, + 287, + 253 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 110, + 287, + 253 + ], + "spans": [ + { + "bbox": [ + 46, + 110, + 287, + 253 + ], + "type": "text", + "content": "Recently, object detection frameworks based on the Transformer have gained widespread popularity, such as DETR [5], Deformable DETR [48], etc. Such architectures are RPN-free and background-free, i.e., they do not involve RPN and background class, which are naturally conducive to building zero-shot object detection methods. However, how to build a ZSD method based on DETR detectors poses new challenges. An intuitive idea is to replace DETR's classification head with a zero-shot classifier based on cosine similarity [43]. However, such a method simply treats DETR as a large RPN for proposals generation, the overall framework is essentially the same as previous works." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 256, + 287, + 434 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 256, + 287, + 434 + ], + "spans": [ + { + "bbox": [ + 46, + 256, + 287, + 434 + ], + "type": "text", + "content": "In this paper, we present the first method that fully explores DETR detectors and meta-learning to perform zero-shot object detection, named Meta-ZSDETR, which can solve the two problems mentioned above that have plagued the field of ZSD for many years, and achieves the state-of-the-art performance. The comparison of Meta-ZSDETR with previous methods is shown in Fig. 1. Different from the previous works that firstly generate class-agnostic proposals and then classify them with visual-semantic alignment module, our method utilizes semantic vectors to guide both proposal generation and classification, which greatly improves the recall of unseen classes. Meanwhile, there is no background class in DETR detectors, which means the confusion between background and unseen classes is no more existent." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "text", + "content": "In order to detect unseen classes, we formalize the training process as an individual episode based meta-learning task. In each episode, we randomly sample an image " + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "text", + "content": " and a set of classes " + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "inline_equation", + "content": "C_{\\pi}" + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "text", + "content": ", which contains the positive classes that appear in " + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "text", + "content": " and negative classes that do not appear. The meta-learning task is to make the model learn to detect all positive classes of " + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "inline_equation", + "content": "C_{\\pi}" + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "text", + "content": " on image " + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "text", + "content": ". Through the meta-learning task, the training and testing can be unified, i.e., in the model testing, we need only to employ the unseen classes as the set " + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "inline_equation", + "content": "C_{\\pi}" + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "text", + "content": ". To enable the model to detect an arbitrary class set, we firstly fuse each object query with a projected semantic vector from the class set " + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "inline_equation", + "content": "C_{\\pi}" + }, + { + "bbox": [ + 46, + 438, + 287, + 714 + ], + "type": "text", + "content": ", which transfers the query from class-agnostic to class-specific. Then, the decoder takes the class-specific query as input and predicts the locations of class-specific boxes, together with the probabilities that the boxes belong to the fused class. To achieve the above goal, we propose meta-contrastive learning, where all predictions are split into three different types and different combinations of them are chosen to optimize three different heads, i.e., the regression head to generate the locations of class-specific boxes, the classification head to predict the accuracy of generated boxes, and the contrastive head to separate different classes in visual space for performance improving" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 305, + 72, + 545, + 119 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 119 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 119 + ], + "type": "text", + "content": "with a contrastive-reconstruction loss. The bipartite matching and loss calculation are performed in a class-by-class manner, and the final loss is averaged over all classes in the sampled class set " + }, + { + "bbox": [ + 305, + 72, + 545, + 119 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 305, + 72, + 545, + 119 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 317, + 121, + 527, + 132 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 121, + 527, + 132 + ], + "spans": [ + { + "bbox": [ + 317, + 121, + 527, + 132 + ], + "type": "text", + "content": "In summary, our major contributions are as follows:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 317, + 140, + 545, + 324 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 317, + 140, + 545, + 200 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 140, + 545, + 200 + ], + "spans": [ + { + "bbox": [ + 317, + 140, + 545, + 200 + ], + "type": "text", + "content": "- We present the first method that explores DETR and meta-learning to perform zero-shot object detection, which formalizes the training as an individual episode based meta-learning task and ingeniously tackles the two problems that plague ZSD for years." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 209, + 545, + 256 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 209, + 545, + 256 + ], + "spans": [ + { + "bbox": [ + 317, + 209, + 545, + 256 + ], + "type": "text", + "content": "- We propose to train the decoder to directly predict class-specific boxes with class-specific queries as input, under the supervision of our meta-contrastive learning that contains three different heads." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 266, + 545, + 324 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 266, + 545, + 324 + ], + "spans": [ + { + "bbox": [ + 317, + 266, + 545, + 324 + ], + "type": "text", + "content": "- We conduct extensive experiments on two benchmark datasets MSCOCO and PASCAL VOC to evaluate the proposed method Meta-ZSDETR. Experimental results show that our method outperforms the existing ZSD methods." + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 337, + 390, + 350 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 337, + 390, + 350 + ], + "spans": [ + { + "bbox": [ + 306, + 337, + 390, + 350 + ], + "type": "text", + "content": "2. Related work" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 357, + 416, + 369 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 357, + 416, + 369 + ], + "spans": [ + { + "bbox": [ + 306, + 357, + 416, + 369 + ], + "type": "text", + "content": "2.1. Zero-shot learning" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 376, + 545, + 519 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 376, + 545, + 519 + ], + "spans": [ + { + "bbox": [ + 304, + 376, + 545, + 519 + ], + "type": "text", + "content": "Zero-shot learning (ZSL) aims to classify images of unseen classes that do not appear during training. There are two main streams in ZSL: embedding based methods and generative based methods. The key idea of embedding based methods is to learn an embedding function that maps the semantic vectors and visual features into the same embedding space, where the visual features and semantic vectors can be compared directly [1, 4, 10, 21, 37]. Generative based methods aim to synthesize unseen visual features with variational autoencoder [20] and generative adversarial networks [39], which convert the ZSL into a fully supervised way [6, 13, 36, 38]." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 528, + 451, + 540 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 528, + 451, + 540 + ], + "spans": [ + { + "bbox": [ + 306, + 528, + 451, + 540 + ], + "type": "text", + "content": "2.2. Zero-shot object detection" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 545, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 545, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 545, + 545, + 713 + ], + "type": "text", + "content": "Zero-shot object detection (ZSD) has received a great deal of research interest in recent years. Most of ZSD methods are built on Faster R-CNN [11],YOLO [33] and RetinaNet [23]. The process of these methods can be summarized as: generating class-agnostic proposals and classifying proposals into seen/unseen and background classes. The main difference of these methods is that different visual semantic alignment methods are used to complete the classification of proposals. These methods can be divided into two categories: mapping the semantic vectors and visual features to the same embedding space to calculate similarity [2, 40, 41, 32, 44, 12, 25, 18, 7] and synthesizing visual features from semantic vectors [17, 14, 42, 47, 27]. Although previous works have paid great efforts, there are" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "6846" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 143 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 143 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 143 + ], + "type": "text", + "content": "some problems that still have no satisfactory solution, such as the low recall of class-agnostic RPN for unseen classes and the confusion between background and unseen classes. These problems may be caused by the incompatibility of ZSD task and proposals-based architecture such as Faster R-CNN." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 144, + 288, + 240 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 144, + 288, + 240 + ], + "spans": [ + { + "bbox": [ + 46, + 144, + 288, + 240 + ], + "type": "text", + "content": "Different from previous works, Meta-ZSDETR is the first work built on Deformable DETR with meta-learning, where the semantic vectors are guided for class-specific boxes generation, instead of class-agnostic proposals in previous works, resulting in a higher unseen recall and precision. Meanwhile, since there is no background class in DETR detectors, the confusion between background and unseen classes is non-existent." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 251, + 102, + 262 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 251, + 102, + 262 + ], + "spans": [ + { + "bbox": [ + 47, + 251, + 102, + 262 + ], + "type": "text", + "content": "3. Method" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 270, + 157, + 281 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 270, + 157, + 281 + ], + "spans": [ + { + "bbox": [ + 47, + 270, + 157, + 281 + ], + "type": "text", + "content": "3.1. Problem definition" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "spans": [ + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "text", + "content": "Zero-shot object detection (ZSD) aims to detect objects of unseen classes with model trained on the seen classes. Formally, the class space " + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{C}" + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "text", + "content": " in ZSD is divided into seen classes " + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{C}^s" + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "text", + "content": " and unseen classes " + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{C}^u" + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{C} = \\mathcal{C}^s \\cup \\mathcal{C}^u" + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{C}^s \\cap \\mathcal{C}^u = \\emptyset" + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "text", + "content": ". The training set contains objects of seen classes, where each image " + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "text", + "content": " is provided with ground-truth class labels and bounding boxes coordinates. While the test set may contain only unseen objects (ZSD setting) or both seen and unseen classes (GZSD setting). During the training and testing, the semantic vectors " + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "inline_equation", + "content": "\\mathcal{W} = \\{\\mathcal{W}^s, \\mathcal{W}^u\\}" + }, + { + "bbox": [ + 46, + 289, + 287, + 420 + ], + "type": "text", + "content": " is provided for both seen and unseen classes." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 427, + 269, + 441 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 427, + 269, + 441 + ], + "spans": [ + { + "bbox": [ + 47, + 427, + 269, + 441 + ], + "type": "text", + "content": "3.2. Revisit standard DETR in object detection" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 446, + 287, + 494 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 446, + 287, + 494 + ], + "spans": [ + { + "bbox": [ + 46, + 446, + 287, + 494 + ], + "type": "text", + "content": "To begin with, we review the pipeline of a standard DETR in generic object detection, which contains the following steps: set prediction, optimal bipartite matching and loss calculation." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 509, + 140, + 521 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 509, + 140, + 521 + ], + "spans": [ + { + "bbox": [ + 47, + 509, + 140, + 521 + ], + "type": "text", + "content": "3.2.1 Set prediction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 527, + 287, + 563 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 527, + 287, + 563 + ], + "spans": [ + { + "bbox": [ + 46, + 527, + 287, + 563 + ], + "type": "text", + "content": "For an image " + }, + { + "bbox": [ + 46, + 527, + 287, + 563 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 527, + 287, + 563 + ], + "type": "text", + "content": ", the global representation " + }, + { + "bbox": [ + 46, + 527, + 287, + 563 + ], + "type": "inline_equation", + "content": "x_{I}" + }, + { + "bbox": [ + 46, + 527, + 287, + 563 + ], + "type": "text", + "content": " is extracted by the backbone " + }, + { + "bbox": [ + 46, + 527, + 287, + 563 + ], + "type": "inline_equation", + "content": "f_{\\phi}" + }, + { + "bbox": [ + 46, + 527, + 287, + 563 + ], + "type": "text", + "content": " and Transformer encoder " + }, + { + "bbox": [ + 46, + 527, + 287, + 563 + ], + "type": "inline_equation", + "content": "g_{\\psi}" + }, + { + "bbox": [ + 46, + 527, + 287, + 563 + ], + "type": "text", + "content": " successively, which can be expressed as:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 132, + 573, + 287, + 586 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 132, + 573, + 287, + 586 + ], + "spans": [ + { + "bbox": [ + 132, + 573, + 287, + 586 + ], + "type": "interline_equation", + "content": "x _ {I} = g _ {\\psi} \\left(f _ {\\phi} (I)\\right) \\tag {1}", + "image_path": "b57611efc91f44d4dea3d827bd42ab4a073dc6f2f779d29fb554b6752559d350.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "spans": [ + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "type": "text", + "content": "Then, the decoder " + }, + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "type": "inline_equation", + "content": "g_{\\theta}" + }, + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "type": "text", + "content": " infers " + }, + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "type": "text", + "content": " object predictions " + }, + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "type": "inline_equation", + "content": "\\hat{\\mathcal{V}}" + }, + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "type": "text", + "content": " is determined by the number of object queries " + }, + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}" + }, + { + "bbox": [ + 46, + 596, + 287, + 633 + ], + "type": "text", + "content": " that serve as learnable positional embedding:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 134, + 641, + 287, + 654 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 134, + 641, + 287, + 654 + ], + "spans": [ + { + "bbox": [ + 134, + 641, + 287, + 654 + ], + "type": "interline_equation", + "content": "\\hat {\\mathcal {Y}} = g _ {\\theta} \\left(x _ {I}, \\mathcal {Q}\\right) \\tag {2}", + "image_path": "4f1d6b10d96e34c55d4935d0f2b04b7bd0842b5abf6b12050ac6a467cad21ea5.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\hat{\\mathcal{V}} = \\{(\\hat{c}_i,\\hat{b}_i)\\}_{i = 1}^N" + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\mathcal{Q} = \\{q_i\\}_{i = 1}^N" + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "text", + "content": ". For each object query " + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "inline_equation", + "content": "q_{i}" + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "text", + "content": ", the decoder " + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "inline_equation", + "content": "g_{\\theta}" + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "text", + "content": " will output a prediction box, which contains two parts: the predicted class " + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\hat{c}_i" + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "text", + "content": " and predicted box location " + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\hat{b}_i" + }, + { + "bbox": [ + 46, + 664, + 287, + 714 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 72, + 457, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 457, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 457, + 84 + ], + "type": "text", + "content": "3.2.2 Optimal bipartite matching" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "type": "text", + "content": "The optimal bipartite matching is to find the minimal-cost matching between the predictions " + }, + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "type": "inline_equation", + "content": "\\hat{\\mathcal{Y}} = \\{(\\hat{c}_i,\\hat{b}_i)\\}_{i = 1}^N" + }, + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "type": "text", + "content": " and ground-truth boxes " + }, + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "type": "inline_equation", + "content": "\\mathcal{V} = \\{(c_i,b_i)\\}_{i = 1}^N" + }, + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "type": "text", + "content": " (padded with no object " + }, + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "type": "inline_equation", + "content": "\\varnothing" + }, + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "type": "text", + "content": "). Therefore, we search for a permutation of " + }, + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "type": "text", + "content": " elements " + }, + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "type": "inline_equation", + "content": "\\sigma \\in \\mathfrak{S}_N" + }, + { + "bbox": [ + 305, + 91, + 545, + 150 + ], + "type": "text", + "content": " with lowest cost:" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 322, + 158, + 545, + 190 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 322, + 158, + 545, + 190 + ], + "spans": [ + { + "bbox": [ + 322, + 158, + 545, + 190 + ], + "type": "interline_equation", + "content": "\\hat {\\sigma} = \\underset {\\sigma \\in \\mathfrak {S} _ {N}} {\\arg \\min } \\sum_ {i = 1} ^ {N} \\left[ \\mathcal {L} _ {c l s} \\left(c _ {i}, \\hat {c} _ {\\sigma_ {i}}\\right) + \\mathcal {L} _ {l o c} \\left(b _ {i}, \\hat {b} _ {\\sigma_ {i}}\\right) \\right] \\tag {3}", + "image_path": "a64b8784657f7ef9766d0e2a9fdf7e5cdf0ab91581765f2374be62bc303aaa07.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "spans": [ + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{cls}(c_i,\\hat{c}_{\\sigma_i})" + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{loc}(b_i,\\hat{b}_{\\sigma_i})" + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "text", + "content": " are matching cost for class prediction and box location with index " + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "inline_equation", + "content": "\\sigma_{i}" + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "text", + "content": ", respectively. Bipartite matching produces one-to-one assignments, where each prediction " + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "inline_equation", + "content": "(\\hat{c}_i,\\hat{b}_i)" + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "text", + "content": " is assigned to either a ground-truth box " + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "inline_equation", + "content": "(c_{i},b_{i})" + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "inline_equation", + "content": "\\varnothing" + }, + { + "bbox": [ + 305, + 200, + 545, + 273 + ], + "type": "text", + "content": " (no object). The permutation for lowest cost is calculated with Hungarian algorithm." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 286, + 404, + 298 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 286, + 404, + 298 + ], + "spans": [ + { + "bbox": [ + 306, + 286, + 404, + 298 + ], + "type": "text", + "content": "3.2.3 Hungarian loss" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 305, + 545, + 329 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 305, + 545, + 329 + ], + "spans": [ + { + "bbox": [ + 305, + 305, + 545, + 329 + ], + "type": "text", + "content": "Hungarian loss is a widely used loss function in DETR, which takes the following form:" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 314, + 337, + 545, + 370 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 314, + 337, + 545, + 370 + ], + "spans": [ + { + "bbox": [ + 314, + 337, + 545, + 370 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {H u g} = \\sum_ {i = 1} ^ {N} \\left[ \\mathcal {L} _ {c l s} \\left(c _ {i}, \\hat {c} _ {\\hat {\\sigma} _ {i}}\\right) + \\mathbb {1} _ {\\{c _ {i} \\neq \\emptyset \\}} \\mathcal {L} _ {l o c} \\left(b _ {i}, \\hat {b} _ {\\hat {\\sigma} _ {i}}\\right) \\right] \\tag {4}", + "image_path": "40b7c63b36d76da76cfdd0442ca1efbbfd4d228051166088d32d47746fcf85ae.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "spans": [ + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "inline_equation", + "content": "\\hat{\\sigma}" + }, + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "text", + "content": " is the optimal assignment computed in Eq.(3). " + }, + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{cls}" + }, + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "text", + "content": " is the loss for classification, which usually takes the form of focal loss [23] or cross-entropy loss. " + }, + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{loc}" + }, + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "text", + "content": " is the location loss and usually contains " + }, + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "inline_equation", + "content": "l_{1}" + }, + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "text", + "content": " loss and GIoU loss [35]." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 305, + 426, + 545, + 509 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 426, + 545, + 509 + ], + "spans": [ + { + "bbox": [ + 305, + 426, + 545, + 509 + ], + "type": "text", + "content": "Challenge: Since the standard DETR can only locate the boxes and predict the classes of objects in training set, it is unable to detect unseen classes. In this paper, we utilize the meta-learning to make the model learn to detect objects according to the inputted semantic vectors, so that the model has the ability to detect objects of any category, as long as the semantic vector of the corresponding category is input." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 306, + 515, + 383, + 527 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 515, + 383, + 527 + ], + "spans": [ + { + "bbox": [ + 306, + 515, + 383, + 527 + ], + "type": "text", + "content": "3.3. Framework" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "text", + "content": "We present the framework of Meta-ZSDETR in Fig. 2, which is based on Deformable DETR. Meta-ZSDETR follows the paradigm of meta-learning. The training is performed by episode based meta-learning task. In each episode, we randomly sample an image " + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "text", + "content": " and a class set " + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "text", + "content": ". The meta-learning task of each episode is to make the model learn to detect all appeared classes in " + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "text", + "content": " on image " + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "text", + "content": ". Specifically, the image feature is firstly extracted by backbone and Transformer encoder as in Eq.(1). In order for the decoder to detect categories in " + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "text", + "content": ", we add the projected semantic vectors of classes " + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 305, + 534, + 545, + 713 + ], + "type": "text", + "content": " to the object queries, making the queries class-specific. Then, the decoder takes the queries as input and predicts the class-specific boxes directly. To achieve this, the model is optimized with meta-contrastive learning, which contains a regression head to generate the" + } + ] + } + ], + "index": 23 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6847" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 72, + 70, + 521, + 194 + ], + "blocks": [ + { + "bbox": [ + 72, + 70, + 521, + 194 + ], + "lines": [ + { + "bbox": [ + 72, + 70, + 521, + 194 + ], + "spans": [ + { + "bbox": [ + 72, + 70, + 521, + 194 + ], + "type": "image", + "image_path": "221136650e966e25028c4e141636cada1bb0207402e20d8f25021fa0d3ab391f.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "lines": [ + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "type": "text", + "content": "Figure 2. The framework of Meta-ZSDETR. In each episode, a class set " + }, + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "type": "text", + "content": " and an image " + }, + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "type": "text", + "content": " are sampled. The meta-learning task is to make the model learn to detect all appeared classes in " + }, + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "type": "text", + "content": ". Firstly, the image feature " + }, + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "type": "inline_equation", + "content": "x_{I}" + }, + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "type": "text", + "content": " is extracted with backbone and encoder. Then, the projected semantic vectors are added to object queries, making them class-specific. Finally, the decoder " + }, + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "type": "inline_equation", + "content": "g_{\\theta}" + }, + { + "bbox": [ + 46, + 205, + 545, + 251 + ], + "type": "text", + "content": " will takes the queries as input and directly predict class-specific boxes. To achieve this, we train our model with proposed meta-contrastive learning." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 269, + 287, + 318 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 269, + 287, + 318 + ], + "spans": [ + { + "bbox": [ + 46, + 269, + 287, + 318 + ], + "type": "text", + "content": "coordinates of class-specific boxes, a classification to predict the accuracy of generated boxes and a contrastive head that utilize the proposed contrastive-reconstruction loss to further separate different classes in visual space." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 326, + 264, + 339 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 326, + 264, + 339 + ], + "spans": [ + { + "bbox": [ + 47, + 326, + 264, + 339 + ], + "type": "text", + "content": "3.4. Meta-ZSDETR with class-specific queries" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 346, + 287, + 405 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 346, + 287, + 405 + ], + "spans": [ + { + "bbox": [ + 46, + 346, + 287, + 405 + ], + "type": "text", + "content": "To enable the model to detect any unseen class, we fuse the object queries with class semantic information, and make the model learn to predict the bounding boxes for the fused classes. Such a process is carried out in each meta-learning task." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "spans": [ + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": "Specifically, in each episode, we randomly sample a class set " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": " and an image " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": ", where the " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": " satisfies " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi} \\subseteq \\mathcal{C}^s" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": " and each element is unique. Meanwhile, " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi} = \\mathcal{C}_{\\pi}^{+} \\cup \\mathcal{C}_{\\pi}^{-}" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}^{+}" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": " is the positive classes that appeared in image " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}^{-}" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": " is the randomly sampled negative classes that do not appear in " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": " for contrast. Meanwhile, we denote the size of " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "L(\\mathcal{C}_{\\pi})" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "L(\\cdot)" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": " is the operation that calculates size. The positive rate " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "\\frac{L(\\mathcal{C}_{\\pi}^{+})}{L(\\mathcal{C}_{\\pi})}" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": " is set to " + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "inline_equation", + "content": "\\lambda_{\\pi}" + }, + { + "bbox": [ + 46, + 406, + 287, + 516 + ], + "type": "text", + "content": ", which is a hyperparameter." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 517, + 287, + 553 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 517, + 287, + 553 + ], + "spans": [ + { + "bbox": [ + 46, + 517, + 287, + 553 + ], + "type": "text", + "content": "Then, the corresponding semantic vectors " + }, + { + "bbox": [ + 46, + 517, + 287, + 553 + ], + "type": "inline_equation", + "content": "\\mathcal{W}_{\\pi}" + }, + { + "bbox": [ + 46, + 517, + 287, + 553 + ], + "type": "text", + "content": " of class set " + }, + { + "bbox": [ + 46, + 517, + 287, + 553 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 46, + 517, + 287, + 553 + ], + "type": "text", + "content": " are projected from semantic space to the visual space with a linear layer " + }, + { + "bbox": [ + 46, + 517, + 287, + 553 + ], + "type": "inline_equation", + "content": "h_{\\mathcal{W}}" + }, + { + "bbox": [ + 46, + 517, + 287, + 553 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 132, + 564, + 287, + 580 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 132, + 564, + 287, + 580 + ], + "spans": [ + { + "bbox": [ + 132, + 564, + 287, + 580 + ], + "type": "interline_equation", + "content": "\\widetilde {\\mathcal {W} _ {\\pi}} = h _ {\\mathcal {W}} \\left(\\mathcal {W} _ {\\pi}\\right) \\tag {5}", + "image_path": "a5a7b8b97c1008ef3bcda4a147ce7148442b63188c013dedeaec923bd2134283.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "spans": [ + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "inline_equation", + "content": "\\widetilde{\\mathcal{W}_{\\pi}}" + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "text", + "content": " is the projected semantic vectors of class set " + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "text", + "content": ". Since " + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "inline_equation", + "content": "L(\\widetilde{\\mathcal{W}_{\\pi}})\\ll N" + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "text", + "content": ", i.e. the number of semantic vectors is smaller than the number of object queries " + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}" + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "text", + "content": ", we expand " + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "inline_equation", + "content": "\\widetilde{\\mathcal{W}_{\\pi}}" + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "text", + "content": " by duplicating each element in " + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "inline_equation", + "content": "\\widetilde{\\mathcal{W}_{\\pi}}" + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "text", + "content": " for " + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "text", + "content": " times, which satisfies " + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "inline_equation", + "content": "L(\\widetilde{\\mathcal{W}_{\\pi}})\\cdot T\\geqslant N" + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "inline_equation", + "content": "L(\\widetilde{\\mathcal{W}_{\\pi}})\\cdot (T - 1) < N" + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "text", + "content": ". For redundant elements more than " + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 586, + 287, + 663 + ], + "type": "text", + "content": ", we drop them." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 45, + 664, + 287, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 664, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 45, + 664, + 287, + 689 + ], + "type": "text", + "content": "Then, the projected semantic vectors " + }, + { + "bbox": [ + 45, + 664, + 287, + 689 + ], + "type": "inline_equation", + "content": "\\widetilde{\\mathcal{W}_{\\pi}}" + }, + { + "bbox": [ + 45, + 664, + 287, + 689 + ], + "type": "text", + "content": " is added to object queries " + }, + { + "bbox": [ + 45, + 664, + 287, + 689 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}" + }, + { + "bbox": [ + 45, + 664, + 287, + 689 + ], + "type": "text", + "content": " as follows:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 134, + 699, + 287, + 714 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 134, + 699, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 134, + 699, + 287, + 714 + ], + "type": "interline_equation", + "content": "\\mathcal {Q} _ {\\pi} = \\mathcal {Q} \\oplus \\widetilde {\\mathcal {W} _ {\\pi}} \\tag {6}", + "image_path": "b5c0d949ba5a24978762fd61080faf2daaa73c1615ba9f713d93782c4814918c.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 269, + 545, + 305 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 269, + 545, + 305 + ], + "spans": [ + { + "bbox": [ + 304, + 269, + 545, + 305 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 269, + 545, + 305 + ], + "type": "inline_equation", + "content": "\\mathcal{Q}_{\\pi} = \\{q_i^\\pi \\}_{i=1}^N" + }, + { + "bbox": [ + 304, + 269, + 545, + 305 + ], + "type": "text", + "content": " is the class-specific queries that will be inputted into the Transformer decoder " + }, + { + "bbox": [ + 304, + 269, + 545, + 305 + ], + "type": "inline_equation", + "content": "g_{\\theta}" + }, + { + "bbox": [ + 304, + 269, + 545, + 305 + ], + "type": "text", + "content": " with image feature " + }, + { + "bbox": [ + 304, + 269, + 545, + 305 + ], + "type": "inline_equation", + "content": "x_I" + }, + { + "bbox": [ + 304, + 269, + 545, + 305 + ], + "type": "text", + "content": " to generate predictions:" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 391, + 314, + 545, + 328 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 391, + 314, + 545, + 328 + ], + "spans": [ + { + "bbox": [ + 391, + 314, + 545, + 328 + ], + "type": "interline_equation", + "content": "\\hat {\\mathcal {Y}} = g _ {\\theta} \\left(x _ {I}, \\mathcal {Q} _ {\\pi}\\right) \\tag {7}", + "image_path": "f1a7d5f2310c55fa11b8c48bc22caeceab25abe75f86f8e3a723fa999df3269c.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "spans": [ + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "inline_equation", + "content": "\\hat{\\mathcal{V}} = \\{(\\hat{\\delta}_i,\\hat{b}_i)\\}_{i = 1}^N" + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "text", + "content": " is the set of predictions, where " + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "inline_equation", + "content": "\\hat{b}_i" + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "text", + "content": " is predicted box location generated with query " + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "inline_equation", + "content": "q_{i}^{\\pi}" + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "inline_equation", + "content": "\\hat{\\delta}_i" + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "text", + "content": " is the probability of box " + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "inline_equation", + "content": "\\hat{b}_i" + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "text", + "content": " belonging to the fused class, i.e. the class of semantic vector that fused to query " + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "inline_equation", + "content": "q_{i}^{\\pi}" + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "text", + "content": ". Meanwhile, different from the standard DETR that the classification head determines the class of predicted boxes, the class of predicted box " + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "inline_equation", + "content": "\\hat{b}_i" + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "text", + "content": " in Meta-ZSDETR is class-specific and is determined by the class of corresponding query and " + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "inline_equation", + "content": "\\hat{\\delta}_i" + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "text", + "content": " only has one dimension to represent the probability of " + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "inline_equation", + "content": "\\hat{b}_i" + }, + { + "bbox": [ + 304, + 336, + 546, + 460 + ], + "type": "text", + "content": " belongs to the fused class." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 468, + 450, + 480 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 468, + 450, + 480 + ], + "spans": [ + { + "bbox": [ + 306, + 468, + 450, + 480 + ], + "type": "text", + "content": "3.5. Meta-contrastive learning" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 486, + 545, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 486, + 545, + 605 + ], + "spans": [ + { + "bbox": [ + 304, + 486, + 545, + 605 + ], + "type": "text", + "content": "In order for the regression head of decoder " + }, + { + "bbox": [ + 304, + 486, + 545, + 605 + ], + "type": "inline_equation", + "content": "g_{\\theta}" + }, + { + "bbox": [ + 304, + 486, + 545, + 605 + ], + "type": "text", + "content": " to generate more accurate class-specific box coordinate " + }, + { + "bbox": [ + 304, + 486, + 545, + 605 + ], + "type": "inline_equation", + "content": "\\hat{b}_i" + }, + { + "bbox": [ + 304, + 486, + 545, + 605 + ], + "type": "text", + "content": " and classification head to have a stronger discriminative ability of further judging the location accuracy of generated " + }, + { + "bbox": [ + 304, + 486, + 545, + 605 + ], + "type": "inline_equation", + "content": "\\hat{b}_i" + }, + { + "bbox": [ + 304, + 486, + 545, + 605 + ], + "type": "text", + "content": ", we propose the meta-contrastive learning to train the heads of decoder " + }, + { + "bbox": [ + 304, + 486, + 545, + 605 + ], + "type": "inline_equation", + "content": "g_{\\theta}" + }, + { + "bbox": [ + 304, + 486, + 545, + 605 + ], + "type": "text", + "content": ", i.e. a regression head to generate class-specific boxes, a classification head to filter inaccurate boxes, and moreover a contrastive head to further separate different classes in visual space, which will improve the performance of both seen classes and unseen classes." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 605, + 545, + 702 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 545, + 702 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 545, + 702 + ], + "type": "text", + "content": "Meta-contrastive learning performs the matching and optimization in a class-by-class manner. As shown in Fig. 3, for each class " + }, + { + "bbox": [ + 304, + 605, + 545, + 702 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi} \\in \\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 304, + 605, + 545, + 702 + ], + "type": "text", + "content": ", the decoder takes queries of class " + }, + { + "bbox": [ + 304, + 605, + 545, + 702 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 605, + 545, + 702 + ], + "type": "text", + "content": " as input, and the predictions are split into three types: 1) The positive predictions that are assigned to GT box of class " + }, + { + "bbox": [ + 304, + 605, + 545, + 702 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 605, + 545, + 702 + ], + "type": "text", + "content": " by class-specific bipartite matching. 2) The negative predictions that are assigned to any other classes than " + }, + { + "bbox": [ + 304, + 605, + 545, + 702 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 605, + 545, + 702 + ], + "type": "text", + "content": ". 3) The negative predictions that belong to background." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 317, + 702, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 702, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 317, + 702, + 545, + 714 + ], + "type": "text", + "content": "Then, we takes different combinations of three types" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6848" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 48, + 70, + 289, + 198 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 289, + 198 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 289, + 198 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 289, + 198 + ], + "type": "image", + "image_path": "177140d1fb979f02742c666f439bf6db8b569ae17dba4a05c901c14149c88706.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 207, + 288, + 240 + ], + "lines": [ + { + "bbox": [ + 46, + 207, + 288, + 240 + ], + "spans": [ + { + "bbox": [ + 46, + 207, + 288, + 240 + ], + "type": "text", + "content": "Figure 3. All predictions of class " + }, + { + "bbox": [ + 46, + 207, + 288, + 240 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 46, + 207, + 288, + 240 + ], + "type": "text", + "content": " are split into three different types and different combinations of them are utilized to train three different heads." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 259, + 289, + 379 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 259, + 289, + 379 + ], + "spans": [ + { + "bbox": [ + 46, + 259, + 289, + 379 + ], + "type": "text", + "content": "of predictions to train three heads: a) For the classification head, we take all predictions for the training and give them corresponding positive/negative class-specific targets for class " + }, + { + "bbox": [ + 46, + 259, + 289, + 379 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 46, + 259, + 289, + 379 + ], + "type": "text", + "content": ". b) For the regression head, since the regression head aims to generate class-specific boxes of class " + }, + { + "bbox": [ + 46, + 259, + 289, + 379 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 46, + 259, + 289, + 379 + ], + "type": "text", + "content": ", we only utilize the positive predictions for optimization. c) For the contrastive head, since our intention is to separate different classes in visual space, we only use positive predictions of class " + }, + { + "bbox": [ + 46, + 259, + 289, + 379 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 46, + 259, + 289, + 379 + ], + "type": "text", + "content": " and negative predictions of other classes for contrastive-reconstruction loss." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 394, + 220, + 407 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 394, + 220, + 407 + ], + "spans": [ + { + "bbox": [ + 47, + 394, + 220, + 407 + ], + "type": "text", + "content": "3.5.1 Class-specific bipartite matching" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "spans": [ + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "text", + "content": "Our meta-contrastive learning performs the matching in a class-by-class manner. For class " + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi} \\in \\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "text", + "content": ", the predictions generated by queries of class " + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "text", + "content": " are selected for bipartite matching, which is denoted as " + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "inline_equation", + "content": "\\hat{\\mathcal{Y}}_{c_j^\\pi} = \\{(\\hat{\\delta}_{\\tau_i},\\hat{b}_{\\tau_i})\\}_{i = 1}^{T_\\tau}" + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "inline_equation", + "content": "\\{\\tau_i\\}_{i = 1}^{T_\\tau}" + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "text", + "content": " are the indexes for queries of class " + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "text", + "content": " in " + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "text", + "content": " queries. Since each query is duplicated for " + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "inline_equation", + "content": "T - 1" + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "text", + "content": " times, we denote the length uniformly as " + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "inline_equation", + "content": "T_{\\tau}" + }, + { + "bbox": [ + 46, + 413, + 287, + 502 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 503, + 287, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 503, + 287, + 555 + ], + "spans": [ + { + "bbox": [ + 46, + 503, + 287, + 555 + ], + "type": "text", + "content": "Then, the ground-truth matching targets are revised for each class " + }, + { + "bbox": [ + 46, + 503, + 287, + 555 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}\\in \\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 46, + 503, + 287, + 555 + ], + "type": "text", + "content": ". The class-specific matching labels are denoted as " + }, + { + "bbox": [ + 46, + 503, + 287, + 555 + ], + "type": "inline_equation", + "content": "\\Delta_{c_j^\\pi} = \\{\\delta_i^{c_j^\\pi}\\}_{i = 1}^{T_\\tau}" + }, + { + "bbox": [ + 46, + 503, + 287, + 555 + ], + "type": "text", + "content": " (padded with no objects " + }, + { + "bbox": [ + 46, + 503, + 287, + 555 + ], + "type": "inline_equation", + "content": "\\varnothing" + }, + { + "bbox": [ + 46, + 503, + 287, + 555 + ], + "type": "text", + "content": "), which satisfy:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 122, + 564, + 287, + 592 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 122, + 564, + 287, + 592 + ], + "spans": [ + { + "bbox": [ + 122, + 564, + 287, + 592 + ], + "type": "interline_equation", + "content": "\\delta_ {i} ^ {c _ {j} ^ {\\pi}} = \\left\\{ \\begin{array}{l l} 1, & c _ {i} = c _ {j} ^ {\\pi} \\\\ 0, & c _ {i} \\neq c _ {j} ^ {\\pi} \\end{array} \\right. \\tag {8}", + "image_path": "079ea65658684eb3eff8c4c485466db3628faa2ccfe9fe32a5b3a0d50b08cd7a.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "spans": [ + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "inline_equation", + "content": "c_{i}" + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "text", + "content": " is the origin class label for ground-truth box " + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "inline_equation", + "content": "b_{i}" + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "text", + "content": ". The revised matching labels are generated according to whether " + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "inline_equation", + "content": "c_{i}" + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "text", + "content": " is equal to " + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "text", + "content": ". Then, the matching targets " + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}_{c_j^\\pi} = \\{(\\delta_i^{c_j^\\pi}, b_i)\\}_{i=1}^{T_\\tau}" + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "text", + "content": " is utilized for bipartite matching of class " + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "text", + "content": ", where a permutation of " + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "inline_equation", + "content": "T_{\\tau}" + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "text", + "content": " elements " + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "inline_equation", + "content": "\\sigma \\in \\mathfrak{S}_{T_{\\tau}}" + }, + { + "bbox": [ + 47, + 599, + 288, + 675 + ], + "type": "text", + "content": " with lowest cost is search as:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 57, + 683, + 287, + 716 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 683, + 287, + 716 + ], + "spans": [ + { + "bbox": [ + 57, + 683, + 287, + 716 + ], + "type": "interline_equation", + "content": "\\hat {\\sigma} = \\underset {\\sigma \\in \\mathfrak {S} _ {T \\tau}} {\\arg \\min } \\sum_ {i = 1} ^ {T _ {\\tau}} \\left[ \\mathcal {L} _ {c l s} (\\delta_ {i} ^ {e _ {j} ^ {\\pi}}, \\hat {\\delta} _ {\\tau_ {\\sigma_ {i}}}) + \\mathcal {L} _ {l o c} (b _ {i}, \\hat {b} _ {\\tau_ {\\sigma_ {i}}}) \\right] \\tag {9}", + "image_path": "e3594eb07b718ddb961bd33b89a24d92b8a5027deeb5c2862f4790f93d0ca8cd.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "\\hat{\\sigma}" + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "content": " is the optimal assignment between matching targets " + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "\\mathcal{V}_{c_j^\\pi}" + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "content": " and predictions " + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "\\hat{\\mathcal{V}}_{c_j^\\pi}" + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{cls}" + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{loc}" + }, + { + "bbox": [ + 305, + 72, + 545, + 109 + ], + "type": "text", + "content": " are the same as that in Eq.(3)." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 122, + 397, + 133 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 122, + 397, + 133 + ], + "spans": [ + { + "bbox": [ + 306, + 122, + 397, + 133 + ], + "type": "text", + "content": "3.5.2 Loss function" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 139, + 545, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 139, + 545, + 185 + ], + "spans": [ + { + "bbox": [ + 304, + 139, + 545, + 185 + ], + "type": "text", + "content": "Based on " + }, + { + "bbox": [ + 304, + 139, + 545, + 185 + ], + "type": "inline_equation", + "content": "\\hat{\\sigma}" + }, + { + "bbox": [ + 304, + 139, + 545, + 185 + ], + "type": "text", + "content": ", predictions in " + }, + { + "bbox": [ + 304, + 139, + 545, + 185 + ], + "type": "inline_equation", + "content": "\\hat{Y}_{c_j^\\pi}" + }, + { + "bbox": [ + 304, + 139, + 545, + 185 + ], + "type": "text", + "content": " are split into three types mentioned above, i.e. positive and two types of negative ones, and loss function of class " + }, + { + "bbox": [ + 304, + 139, + 545, + 185 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 139, + 545, + 185 + ], + "type": "text", + "content": " for three heads are calculated as follows:" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 188, + 545, + 227 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 188, + 545, + 227 + ], + "spans": [ + { + "bbox": [ + 306, + 188, + 545, + 227 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {c _ {j} ^ {\\pi}} = \\sum_ {i = 1} ^ {T _ {\\tau}} \\left[ \\mathcal {L} _ {c l s} \\left(\\delta_ {i} ^ {c _ {j} ^ {\\pi}}, \\hat {\\delta} _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) + \\mathbb {1} _ {\\left(c _ {i} = c _ {j} ^ {\\pi}\\right)} \\mathcal {L} _ {l o c} \\left(b _ {i}, \\hat {b} _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) \\right] + \\mathcal {L} _ {c o n t} \\tag {10}", + "image_path": "2be3c8cce63aca53bcfc52498868650ff07e2a5b1aead999be0e628a8eac54c3.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "spans": [ + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "type": "text", + "content": "where the loss " + }, + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{c_j^\\pi}" + }, + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "type": "text", + "content": " for class " + }, + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "type": "text", + "content": " is composed of classification loss " + }, + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{cls}" + }, + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "type": "text", + "content": ", regression loss " + }, + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{loc}" + }, + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "type": "text", + "content": " and contrastive-reconstruction loss " + }, + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{cont}" + }, + { + "bbox": [ + 304, + 228, + 545, + 263 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "spans": [ + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "type": "text", + "content": "Classification loss. " + }, + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{cls}" + }, + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "type": "text", + "content": " takes all predictions as input and makes the model learn to distinguish whether a predicted box belongs to " + }, + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "type": "text", + "content": ". The predicted box has the label " + }, + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "type": "inline_equation", + "content": "\\delta_{i}^{c_{j}^{\\pi}} = 1" + }, + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "type": "text", + "content": " if and only if it is assigned to a ground-truth box with class label " + }, + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "type": "text", + "content": ". We implement " + }, + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{cls}" + }, + { + "bbox": [ + 304, + 263, + 545, + 328 + ], + "type": "text", + "content": " with focal loss [23]." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "spans": [ + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "text", + "content": "Regression loss. Since our intention is to generate class-specific boxes, i.e. input decoder with query of class " + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "text", + "content": " and output box of class " + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "text", + "content": ", we only select the ground-truth box with class label " + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "text", + "content": " for optimization, i.e. " + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "inline_equation", + "content": "\\delta_{i}^{c_{j}^{\\pi}} = 1" + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "text", + "content": ", making the predicted boxes to be closer to GT boxes with class label " + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "text", + "content": ". The " + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{loc}" + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "text", + "content": " is implemented with " + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "inline_equation", + "content": "l_{1}" + }, + { + "bbox": [ + 304, + 328, + 545, + 405 + ], + "type": "text", + "content": " loss and GIoU loss [35]." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 405, + 545, + 487 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 405, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 304, + 405, + 545, + 487 + ], + "type": "text", + "content": "Contrastive-reconstruction loss. In ZSD tasks, the original visual space is not well-structured due to the lack of discriminative information, many previous works solved it by introducing a reconstruction loss to guide the distribution of visual features. Here, we combine the reconstruction loss and contrastive loss to bring a higher intra-class compactness and inter-class separability of the visual structure." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "spans": [ + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "text", + "content": "In particular, we project the last hidden features of decoder to the semantic space, where the projected hidden features of positive predictions are constraint to be as close as possible to " + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "inline_equation", + "content": "\\omega_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "text", + "content": ", which is the semantic vector of class " + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "text", + "content": " and the negative ones are constraint to be as far as possible to " + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "inline_equation", + "content": "\\omega_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "text", + "content": ". Formally, we denote the last hidden feature of optimal box " + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "inline_equation", + "content": "(\\hat{\\delta}_{\\tau_{\\hat{\\sigma}_i}},\\hat{b}_{\\tau_{\\hat{\\sigma}_i}})" + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "text", + "content": " that matched to GT box " + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "inline_equation", + "content": "(c_i,b_i)" + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "text", + "content": " as " + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "inline_equation", + "content": "z_{\\tau_{\\hat{\\sigma}_k}}" + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "text", + "content": " and the " + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{cont}" + }, + { + "bbox": [ + 304, + 488, + 545, + 586 + ], + "type": "text", + "content": " is formulated as:" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 345, + 594, + 545, + 628 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 345, + 594, + 545, + 628 + ], + "spans": [ + { + "bbox": [ + 345, + 594, + 545, + 628 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {c o n t}} = \\frac {1}{N _ {\\text {p o s}}} \\sum_ {i = 1} ^ {T _ {\\tau}} \\mathbb {1} _ {\\left(c _ {i} = c _ {j} ^ {\\pi}\\right)} \\mathcal {L} _ {\\text {c o n t}} \\left(z _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) \\tag {11}", + "image_path": "dd1e6976f08ecfcf692b96f9ff31600c76d2fdabbb44bb84e3976851015192b3.jpg" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 306, + 635, + 545, + 677 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 635, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 306, + 635, + 545, + 677 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {c o n t}} \\left(z _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) = - \\log \\frac {\\exp \\left[ h _ {\\rho} \\left(z _ {\\tau_ {\\hat {\\sigma} _ {i}}}\\right) \\cdot \\omega_ {j} ^ {\\pi} / \\kappa \\right]}{\\sum_ {k = 1} ^ {T _ {\\tau}} \\mathbb {1} _ {(c _ {k} \\neq \\varnothing)} \\exp \\left[ h _ {\\rho} \\left(z _ {\\tau_ {\\hat {\\sigma} _ {k}}}\\right) \\cdot \\omega_ {j} ^ {\\pi} / \\kappa \\right]} \\tag {12}", + "image_path": "93eb3cdb24c13b9ed3ed0225cf50f4bc8712c8c669a69f726b12a4cd98205c80.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "type": "inline_equation", + "content": "h_{\\rho}" + }, + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "type": "text", + "content": " is a linear layer that projects the hidden feature to the semantic space. " + }, + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "type": "inline_equation", + "content": "N_{pos}" + }, + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "type": "text", + "content": " is the number of positive predictions of class " + }, + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "type": "inline_equation", + "content": "\\kappa" + }, + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "type": "text", + "content": " is a temperature hyper-parameter" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6849" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "type": "text", + "content": "as in InfoNCE [28]. The optimization of the above loss function increases the instance-level similarity between projected hidden features of positive predictions with semantic vector " + }, + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "type": "inline_equation", + "content": "\\omega_{j}^{\\pi}" + }, + { + "bbox": [ + 46, + 72, + 287, + 132 + ], + "type": "text", + "content": " and space the negative ones. As a result, visual features of the same class will form a tighter cluster." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 133, + 287, + 192 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 133, + 287, + 192 + ], + "spans": [ + { + "bbox": [ + 46, + 133, + 287, + 192 + ], + "type": "text", + "content": "Total loss function. We compute the loss function with Eq.(10) for each class " + }, + { + "bbox": [ + 46, + 133, + 287, + 192 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi} \\in \\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 46, + 133, + 287, + 192 + ], + "type": "text", + "content": ", separately. For negative classes " + }, + { + "bbox": [ + 46, + 133, + 287, + 192 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}^{-}" + }, + { + "bbox": [ + 46, + 133, + 287, + 192 + ], + "type": "text", + "content": ", only classification loss is calculated. Finally, the loss of current episode is averaged over all classes in sampled class set " + }, + { + "bbox": [ + 46, + 133, + 287, + 192 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 46, + 133, + 287, + 192 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 121, + 196, + 287, + 232 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 121, + 196, + 287, + 232 + ], + "spans": [ + { + "bbox": [ + 121, + 196, + 287, + 232 + ], + "type": "interline_equation", + "content": "\\mathcal {L} = \\frac {1}{L \\left(\\mathcal {C} _ {\\pi}\\right)} \\sum_ {j = 1} ^ {L \\left(\\mathcal {C} _ {\\pi}\\right)} \\mathcal {L} _ {c _ {j} ^ {\\pi}} \\tag {13}", + "image_path": "0e51d838776c36b4f5028ddc2e19803b785aa0cc7b3c35646119aab30b9d32ac.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 236, + 287, + 260 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 236, + 287, + 260 + ], + "spans": [ + { + "bbox": [ + 46, + 236, + 287, + 260 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 236, + 287, + 260 + ], + "type": "inline_equation", + "content": "L(\\mathcal{C}_{\\pi})" + }, + { + "bbox": [ + 46, + 236, + 287, + 260 + ], + "type": "text", + "content": " is the number of classes in " + }, + { + "bbox": [ + 46, + 236, + 287, + 260 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 46, + 236, + 287, + 260 + ], + "type": "text", + "content": ". We utilize " + }, + { + "bbox": [ + 46, + 236, + 287, + 260 + ], + "type": "inline_equation", + "content": "\\mathcal{L}" + }, + { + "bbox": [ + 46, + 236, + 287, + 260 + ], + "type": "text", + "content": " for model optimization." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 269, + 128, + 282 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 269, + 128, + 282 + ], + "spans": [ + { + "bbox": [ + 47, + 269, + 128, + 282 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 288, + 157, + 301 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 288, + 157, + 301 + ], + "spans": [ + { + "bbox": [ + 47, + 288, + 157, + 301 + ], + "type": "text", + "content": "4.1. Datasets and splits" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 306, + 287, + 342 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 306, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 46, + 306, + 287, + 342 + ], + "type": "text", + "content": "Following previous works [40, 17], we takes two benchmark datasets for evaluation: PASCAL VOC 2007+2012 [9] and MS COCO 2014 [24]." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 342, + 287, + 474 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 342, + 287, + 474 + ], + "spans": [ + { + "bbox": [ + 46, + 342, + 287, + 474 + ], + "type": "text", + "content": "Datasets: PASCAL VOC contains 20 classes of objects for object detection. More specifically, the PASCAL VOC 2,007 is composed of 2,501 training images, 2,510 validation images, and 5,011 test images. The PASCAL VOC 2012 dataset comprises 5,717 training images and 5,823 validation images, without test images released. MS COCO 2014 is a benchmark dataset designed for object detection and semantic segmentation tasks, which contains 82,783 training and 40,504 validation images from 80 categories. For PASCAL VOC and MS COCO, we adopt the Fast-Text [26] to extract the semantic vectors following [14, 17]." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 474, + 287, + 558 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 474, + 287, + 558 + ], + "spans": [ + { + "bbox": [ + 46, + 474, + 287, + 558 + ], + "type": "text", + "content": "Seen/unseen splits: All splits follow the previous setting [40, 17]. For PASCAL VOC, we use a 16/4 split proposed in [7]. For MS COCO, we follow the same procedures described in [2, 29, 17] to take 2 different splits, i.e. 48/17 and 65/15. For all datasets, the images that contain unseen classes in the training set are removed to guarantee that unseen objects will not be available during training." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 563, + 167, + 576 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 563, + 167, + 576 + ], + "spans": [ + { + "bbox": [ + 47, + 563, + 167, + 576 + ], + "type": "text", + "content": "4.2. Evaluation protocols" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 582, + 287, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 287, + 665 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 287, + 665 + ], + "type": "text", + "content": "We adopt the widely-used evaluation protocols proposed in [2, 7]. For PASCAL VOC, mAP with IoU threshold 0.5 is used to evaluate the performance. For MS COCO, mAP and recall@100 with three different IoU threshold (i.e. 0.4, 0.5 and 0.6) are utilized for evaluation. For GZSD setting that contains both seen and unseen classes, the performance is evaluated by Harmonic Mean (HM)." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 671, + 178, + 684 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 671, + 178, + 684 + ], + "spans": [ + { + "bbox": [ + 47, + 671, + 178, + 684 + ], + "type": "text", + "content": "4.3. Implementation details" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "type": "text", + "content": "We build Meta-ZSDETR on Deformable DETR [48] with ResNet-50 [16] as backbone. The number of queries" + } + ] + } + ], + "index": 12 + }, + { + "type": "table", + "bbox": [ + 309, + 70, + 544, + 208 + ], + "blocks": [ + { + "bbox": [ + 309, + 70, + 544, + 208 + ], + "lines": [ + { + "bbox": [ + 309, + 70, + 544, + 208 + ], + "spans": [ + { + "bbox": [ + 309, + 70, + 544, + 208 + ], + "type": "table", + "html": "
MethodZSDGZSD
SUHM
SAN [31]59.148.037.041.8
HRE [8]54.262.425.536.2
PL [30]62.1---
BLC [45]55.258.222.932.9
SU [15]64.9---
Robust-Syn [17]65.547.149.148.1
ContrastZSD [40]65.763.246.553.6
Meta-ZSDETR70.367.656.361.4
", + "image_path": "5240e18f08495e95b74991a18cf40788e18a8d8e4e7531c146c03ebd1794353c.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_body" + } + ], + "index": 13 + }, + { + "type": "table", + "bbox": [ + 307, + 257, + 545, + 378 + ], + "blocks": [ + { + "bbox": [ + 305, + 215, + 545, + 248 + ], + "lines": [ + { + "bbox": [ + 305, + 215, + 545, + 248 + ], + "spans": [ + { + "bbox": [ + 305, + 215, + 545, + 248 + ], + "type": "text", + "content": "Table 1. The results of mAP in PASCAL VOC with IoU=0.5 under ZSD and GZSD settings. Here, \"S\" denotes seen classes, \"U\" denotes unseen classes and \"HM\" denotes harmonic mean." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 307, + 257, + 545, + 378 + ], + "lines": [ + { + "bbox": [ + 307, + 257, + 545, + 378 + ], + "spans": [ + { + "bbox": [ + 307, + 257, + 545, + 378 + ], + "type": "table", + "html": "
MethodcardogsofatrainmAP
SAN [31]56.285.362.626.457.6
HRE [8]55.082.055.026.054.5
PL [30]63.787.253.244.162.1
BLC [45]43.78660.830.155.2
SU [15]59.692.762.345.264.9
Robust-Syn [17]60.193.059.749.165.5
ContrastZSD [40]65.586.463.147.965.7
Meta-ZSDETR69.092.465.754.170.3
", + "image_path": "59989c2c44161919d6667a987c9dae207b8f558c6dce89adbe5df85dab404013.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "table_body" + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 385, + 545, + 407 + ], + "lines": [ + { + "bbox": [ + 305, + 385, + 545, + 407 + ], + "spans": [ + { + "bbox": [ + 305, + 385, + 545, + 407 + ], + "type": "text", + "content": "Table 2. Class-wise AP and mAP on unseen classes in PASCAL VOC under ZSD setting." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "spans": [ + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "text", + "content": " is set to 900. For the sampled class set " + }, + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "inline_equation", + "content": "\\mathcal{C}_{\\pi}" + }, + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "text", + "content": ", the positive classes consist of the classes that appear in the image and the negative classes is sampled from " + }, + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "inline_equation", + "content": "\\mathcal{C}^s" + }, + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "text", + "content": ". The positive rate " + }, + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "inline_equation", + "content": "\\lambda_{\\pi}" + }, + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "text", + "content": " is set to 0.5. The number of Transformer encoder layers and decoder layers is set to 6. The temperature hyperparameter " + }, + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "inline_equation", + "content": "\\kappa" + }, + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "text", + "content": " in Eq.(12) is set to 0.2. We train our model for total 500,000 iterations with batch size 16, i.e. each iteration contains 16 episodes in parallel. Following Deformable DETR, different coefficients are utilized to weight different loss functions, where 1.0 is used for classification loss, 5.0 is used for " + }, + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "inline_equation", + "content": "l_1" + }, + { + "bbox": [ + 304, + 428, + 545, + 583 + ], + "type": "text", + "content": " loss of regression head, 2.0 is used for GIoU loss of regression head and 1.0 is used for contrastive-reconstruction loss. More details can refer to our code." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 592, + 491, + 605 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 592, + 491, + 605 + ], + "spans": [ + { + "bbox": [ + 305, + 592, + 491, + 605 + ], + "type": "text", + "content": "4.4. Comparison with existing methods" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 306, + 610, + 403, + 621 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 610, + 403, + 621 + ], + "spans": [ + { + "bbox": [ + 306, + 610, + 403, + 621 + ], + "type": "text", + "content": "4.4.1 PASCAL VOC" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 629, + 545, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 545, + 677 + ], + "type": "text", + "content": "We present the results of PASCAL VOC in Tab. 1, where we can see that our method performs best among all existing methods under both ZSD and GZSD settings, and lift the mAP in PASCAL VOC to a higher level." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 713 + ], + "type": "text", + "content": "Specifically, in ZSD setting, Meta-ZSDETR achieves 70.3 mAP and outperform the second-best model ContrastZSD [40] by a large margin of 4.6 mAP, which is the" + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6850" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 47, + 71, + 293, + 297 + ], + "blocks": [ + { + "bbox": [ + 47, + 71, + 293, + 297 + ], + "lines": [ + { + "bbox": [ + 47, + 71, + 293, + 297 + ], + "spans": [ + { + "bbox": [ + 47, + 71, + 293, + 297 + ], + "type": "table", + "html": "
MethodSplitRecall@100mAP
IoU=0.4IoU=0.5IoU=0.6IoU=0.5
DSES [3]48/1740.227.213.60.5
TD [22]48/1745.534.318.1-
PL [30]48/17-43.5-10.1
BLC [45]48/1751.348.845.010.6
ZSDTR [43]48/1751.848.544.510.4
Robust-Syn [17]48/1758.153.547.913.4
ContrastZSD [40]48/1756.152.447.212.5
Meta-ZSDETR48/1762.359.854.215.1
PL [30]65/15-37.7-12.4
BLC [45]65/1557.254.751.214.7
SU [15]65/1554.454.047.019.0
ZSDTR [43]65/1563.860.356.513.2
Robust-Syn [17]65/1565.362.355.919.8
ContrastZSD [40]65/1562.359.555.118.6
Meta-ZSDETR65/1569.166.759.022.5
", + "image_path": "02c490e7734e88986d7341857c206cceddefd3baa257198bab62e6697ca9cc45.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 46, + 304, + 287, + 327 + ], + "lines": [ + { + "bbox": [ + 46, + 304, + 287, + 327 + ], + "spans": [ + { + "bbox": [ + 46, + 304, + 287, + 327 + ], + "type": "text", + "content": "Table 3. ZSD performance of Recall@100 and mAP with different IoU thresholds on MS COCO dataset." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 345, + 287, + 368 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 345, + 287, + 368 + ], + "spans": [ + { + "bbox": [ + 46, + 345, + 287, + 368 + ], + "type": "text", + "content": "first time to boost the performance of ZSD setting on PASCAL VOC to over " + }, + { + "bbox": [ + 46, + 345, + 287, + 368 + ], + "type": "inline_equation", + "content": "70\\mathrm{mAP}" + }, + { + "bbox": [ + 46, + 345, + 287, + 368 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 369, + 287, + 502 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 369, + 287, + 502 + ], + "spans": [ + { + "bbox": [ + 46, + 369, + 287, + 502 + ], + "type": "text", + "content": "For GZSD setting, our method also achieves SOTAs in all three metrics, i.e. mAP on seen classes, unseen classes and harmonic mean, which brings about 4.4, 9.8 and 7.8 points improvement, respectively. It is worth noting that the improvement of our method on unseen classes in GZSD setting is extremely large, which proves that our method has a strong generalization on unseen classes, and can alleviate the problem that the unseen classes tend to be misclassified into seen classes to a certain extent. We also report class-wise mAP in ZSD setting in Tab. 2, where our method achieves the best performance on 3 classes." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 515, + 128, + 526 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 515, + 128, + 526 + ], + "spans": [ + { + "bbox": [ + 47, + 515, + 128, + 526 + ], + "type": "text", + "content": "4.4.2 MS COCO" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 533, + 287, + 582 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 533, + 287, + 582 + ], + "spans": [ + { + "bbox": [ + 46, + 533, + 287, + 582 + ], + "type": "text", + "content": "We perform experiments on MS COCO, where the results of ZSD setting is shown in Tab. 3 and the results of GZSD setting is shown in Tab. 4. We can see that Meta-ZSDETR achieves the best results in all metrics under all settings." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 582, + 287, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 287, + 689 + ], + "type": "text", + "content": "For ZSD setting, we can see that mAP of our method in 48/17 and 65/15 splits outperforms the second-best by a margin of 1.7 and " + }, + { + "bbox": [ + 46, + 582, + 287, + 689 + ], + "type": "inline_equation", + "content": "2.7\\mathrm{mAP}" + }, + { + "bbox": [ + 46, + 582, + 287, + 689 + ], + "type": "text", + "content": ", respectively, which demonstrates that our method generalizes well to unseen classes. Meanwhile, we can see that Recall@100 decrease as the IoU increases in all methods. Compared with other methods, Meta-ZSDETR has a smaller drop, which is benefit from that our decoder can generate more accurate boxes with class semantic information as input." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "type": "text", + "content": "For GZSD setting, our method achieves SOTAs in both seen and unseen classes. The harmonic means of mAP un" + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 306, + 71, + 552, + 274 + ], + "blocks": [ + { + "bbox": [ + 306, + 71, + 552, + 274 + ], + "lines": [ + { + "bbox": [ + 306, + 71, + 552, + 274 + ], + "spans": [ + { + "bbox": [ + 306, + 71, + 552, + 274 + ], + "type": "table", + "html": "
MethodSplitRecall@100mAP
SUHMSUHM
PL [30]48/1738.226.331.235.94.17.4
BLC [45]48/1757.646.451.442.14.58.2
ZSDTR [43]48/1774.348.460.548.55.69.5
Robust-Syn [17]48/1759.758.859.242.313.420.4
ContrastZSD [40]48/1765.752.458.345.16.311.1
Meta-ZSDETR48/1774.359.065.848.714.622.5
PL [30]65/1536.437.236.834.112.418.2
BLC [45]65/1556.451.753.936.013.119.2
SU [15]65/1557.753.955.836.919.025.1
ZSDTR [43]65/1569.159.561.140.613.220.2
Robust-Syn [17]65/1558.661.860.237.419.826.0
ContrastZSD [40]65/1562.958.660.740.216.523.4
Meta-ZSDETR65/1571.165.468.145.921.729.5
", + "image_path": "7a0fbbed65d9f685bdcf8ab57e00bc19edb1a2830818fc18c244a21a15d935e1.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 305, + 281, + 545, + 303 + ], + "lines": [ + { + "bbox": [ + 305, + 281, + 545, + 303 + ], + "spans": [ + { + "bbox": [ + 305, + 281, + 545, + 303 + ], + "type": "text", + "content": "Table 4. GZSD performance of Recall@100 and mAP with IoU=0.5 on MS COCO dataset." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 341, + 311, + 511, + 384 + ], + "blocks": [ + { + "bbox": [ + 341, + 311, + 511, + 384 + ], + "lines": [ + { + "bbox": [ + 341, + 311, + 511, + 384 + ], + "spans": [ + { + "bbox": [ + 341, + 311, + 511, + 384 + ], + "type": "table", + "html": "
LocClsContSeenUnseen
✓39.914.5
✓✓44.820.6
✓✓40.615.3
✓✓✓45.921.7
", + "image_path": "1add503ae86270c5d60228c566750b01b6fa387feff178884e89f8d317a97066.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 306, + 392, + 544, + 403 + ], + "lines": [ + { + "bbox": [ + 306, + 392, + 544, + 403 + ], + "spans": [ + { + "bbox": [ + 306, + 392, + 544, + 403 + ], + "type": "text", + "content": "Table 5. Ablation study of different combinations of loss functions." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 423, + 545, + 508 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 423, + 545, + 508 + ], + "spans": [ + { + "bbox": [ + 304, + 423, + 545, + 508 + ], + "type": "text", + "content": "der 48/17 and 65/15 splits are improved from 20.4 to 22.5, and from 26.0 to 29.5, demonstrating the effectiveness and superiority of our method. Meanwhile, the Recall@100 also improves due to the powerful class-specific boxes generation capabilities. We also report the class-wise AP in 65/15 split of MS COCO, which can be found in our supplementary material." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 515, + 398, + 528 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 515, + 398, + 528 + ], + "spans": [ + { + "bbox": [ + 306, + 515, + 398, + 528 + ], + "type": "text", + "content": "4.5. Ablation study" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 533, + 545, + 582 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 545, + 582 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 545, + 582 + ], + "type": "text", + "content": "We analyze the effects of various components in Meta-ZSDETR. Unless otherwise specified, the experiments are carried out on MS COCO with 65/15 split under GZSD setting and use mAP with IoU=0.5 as metric." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": "Effects of different loss functions. Here, we analyze the effects of three loss functions in meta-contrastive learning. We utilize different combinations of regression loss " + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{loc}" + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": ", classification loss " + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{cls}" + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": " and contrastive-reconstruction loss " + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{cont}" + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": " to optimize the model, and show the results in Tab. 5. Since the regression loss is necessary, we keep it for all combinations. For model without classification loss " + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{cls}" + }, + { + "bbox": [ + 304, + 582, + 545, + 713 + ], + "type": "text", + "content": ", we do not perform the boxes filter and directly use the class-specific boxes predicted from regression head, where the scores are generated randomly. As we can see, if the model is only trained with regression head to gen" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "6851" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 54, + 70, + 281, + 193 + ], + "blocks": [ + { + "bbox": [ + 54, + 70, + 281, + 193 + ], + "lines": [ + { + "bbox": [ + 54, + 70, + 281, + 193 + ], + "spans": [ + { + "bbox": [ + 54, + 70, + 281, + 193 + ], + "type": "table", + "html": "
Heads\\( \\hat{y}_{pos} \\)\\( \\hat{y}_{other} \\)\\( \\hat{y}_{bg} \\)SeenUnseen
Classification Head✓✓43.717.9
✓✓44.819.0
✓✓✓45.921.7
Regression Head✓45.921.7
✓✓42.116.5
Contrastive Head✓45.121.0
✓✓45.921.7
✓✓✓45.421.3
", + "image_path": "eec84ac3588a8481c62518ad3d2c0d03d921cafab99e904c1aa762b34c0ab9dd.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 201, + 287, + 222 + ], + "lines": [ + { + "bbox": [ + 47, + 201, + 287, + 222 + ], + "spans": [ + { + "bbox": [ + 47, + 201, + 287, + 222 + ], + "type": "text", + "content": "Table 6. Ablation study on using different combinations of predictions to train three heads." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 243, + 287, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 243, + 287, + 361 + ], + "spans": [ + { + "bbox": [ + 46, + 243, + 287, + 361 + ], + "type": "text", + "content": "erate class-specific boxes, it can achieve a mAP of 14.5 in unseen classes, which is relatively low, but also surpasses many previous methods. Adding the classification loss will greatly boost the performance of unseen classes to " + }, + { + "bbox": [ + 46, + 243, + 287, + 361 + ], + "type": "inline_equation", + "content": "20.6\\mathrm{mAP}" + }, + { + "bbox": [ + 46, + 243, + 287, + 361 + ], + "type": "text", + "content": ", which thanks to the powerful discriminative ability of the classification head that can filter inaccurate boxes. Meanwhile, the contrastive-reconstruction loss can improve the performance with and without the classification head about 1 point. Finally, the combination of three losses achieves the best performance." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "spans": [ + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "text", + "content": "Study for training of different heads. As describe, based on the class-specific bipartite matching for class " + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "text", + "content": ", all predictions are split into three different types: the positive predictions " + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "inline_equation", + "content": "\\hat{Y}_{pos}" + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "text", + "content": " assigned to GT boxes of " + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "text", + "content": ", the negative predictions " + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "inline_equation", + "content": "\\hat{Y}_{other}" + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "text", + "content": " assigned to other classes and the negative predictions " + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "inline_equation", + "content": "\\hat{Y}_{bg}" + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "text", + "content": " that belong to background. Here, we study different combinations of them to train three heads and the results are shown in Tab. 6. We can see that: 1) For classification head, since it aims to filter all kinds of negative predictions, using all predictions to train it can achieve the best performance. 2) For regression head, if we train it with GT boxes of all classes, i.e. using " + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "inline_equation", + "content": "\\hat{Y}_{pos}" + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "inline_equation", + "content": "\\hat{Y}_{other}" + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "text", + "content": ", the regression head will degenerate into a class-agnostic RPN, which will greatly reduce the recall of unseen classes, thus lead to a lower mAP. 3) For contrastive head, on one hand, if we only use " + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "inline_equation", + "content": "\\hat{Y}_{pos}" + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "text", + "content": " for training, it will degenerate into a reconstruction loss, which has been widely used in previous works and it will bring a 0.4 mAP improvement in unseen classes compared with the version without it. On the other hand, compared with using all predictions, removing background predictions will make the contrastive head focus on distinguishing " + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "inline_equation", + "content": "\\hat{Y}_{other}" + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "text", + "content": " and inputed semantic vectors of class " + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "inline_equation", + "content": "c_{j}^{\\pi}" + }, + { + "bbox": [ + 46, + 363, + 288, + 640 + ], + "type": "text", + "content": ", thus brings more improvement." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 642, + 287, + 714 + ], + "type": "text", + "content": "Visualization for contrastive-reconstruction loss. Here, we study the influence of contrastive-reconstruction loss on visual space by visualizing the distribution of hidden features with t-SNE. We visualize the last hidden features of decoder in unseen classes of PASCAL VOC. The result is shown in Fig. 4. As we can see, our contrastive" + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 312, + 75, + 421, + 188 + ], + "blocks": [ + { + "bbox": [ + 312, + 75, + 421, + 188 + ], + "lines": [ + { + "bbox": [ + 312, + 75, + 421, + 188 + ], + "spans": [ + { + "bbox": [ + 312, + 75, + 421, + 188 + ], + "type": "image", + "image_path": "82eafe7a1ae372f9a1ec5a0c2466cc28ad5ee6521d163acf4375d75c75fd4203.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 201, + 545, + 236 + ], + "lines": [ + { + "bbox": [ + 304, + 201, + 545, + 236 + ], + "spans": [ + { + "bbox": [ + 304, + 201, + 545, + 236 + ], + "type": "text", + "content": "Figure 4. The t-SNE visualization of the last hidden layer of decoder. We can see that the contrastive head can separate different classes in visual space." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 432, + 75, + 541, + 188 + ], + "blocks": [ + { + "bbox": [ + 432, + 75, + 541, + 188 + ], + "lines": [ + { + "bbox": [ + 432, + 75, + 541, + 188 + ], + "spans": [ + { + "bbox": [ + 432, + 75, + 541, + 188 + ], + "type": "image", + "image_path": "e0c24144bb6a945924f28443a81db028ce76c24751dc526ed9e377bc10b8566b.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 331, + 246, + 520, + 355 + ], + "blocks": [ + { + "bbox": [ + 331, + 246, + 520, + 355 + ], + "lines": [ + { + "bbox": [ + 331, + 246, + 520, + 355 + ], + "spans": [ + { + "bbox": [ + 331, + 246, + 520, + 355 + ], + "type": "image", + "image_path": "ec9805989e4ed217a78e22449565b12739f81500cbf5ffd6ce8dfbb33f02af2d.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 306, + 365, + 539, + 377 + ], + "lines": [ + { + "bbox": [ + 306, + 365, + 539, + 377 + ], + "spans": [ + { + "bbox": [ + 306, + 365, + 539, + 377 + ], + "type": "text", + "content": "Figure 5. The effect of number of queries and positive rate of " + }, + { + "bbox": [ + 306, + 365, + 539, + 377 + ], + "type": "inline_equation", + "content": "C_{\\pi}" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 396, + 545, + 431 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 396, + 545, + 431 + ], + "spans": [ + { + "bbox": [ + 304, + 396, + 545, + 431 + ], + "type": "text", + "content": "reconstruction loss can further separate different classes in visual space and bring a higher intra-class compactness and inter-class separability of the visual structure." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "spans": [ + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": "Effect of number of queries and positive rate. We study the effect of number of queries " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": " and positive rate " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "\\lambda_{\\pi}" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": " of sampled class set " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "C_{\\pi}" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": ". We found that " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "\\lambda_{\\pi}" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": " have different influence under different number of queries " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": ". We change the positive rate " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "\\lambda_{\\pi}" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": " in different settings of " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": " and report the mAP of converged model in unseen classes. In each episode, we control " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "\\lambda_{\\pi}" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": " by sampling different number of negative classes. All models are trained for 500,000 episodes. The results are shown in Fig. 5. As we can see, a larger " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": " tends to have a better performance due to a higher recall, and of course a higher amount of calculation. Meanwhile, when " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": " is small (e.g. 100), a small positive rate will greatly reduce the amount of positive queries for training, thereby reducing the model performance. When " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": " is large (e.g. 900), the number of positive queries is guaranteed and more negative queries are needed for the classification head to learn to distinguish among them. Therefore, we can see the best performance is achieved when " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "\\lambda_{\\pi}" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": " is 0.5 and " + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 432, + 546, + 647 + ], + "type": "text", + "content": " is 900." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 658, + 378, + 670 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 658, + 378, + 670 + ], + "spans": [ + { + "bbox": [ + 306, + 658, + 378, + 670 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "content": "In this paper, we present the first work that combine DETR and meta-learning to perform zero-shot object detection, which formalize the training as individual episode" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6852" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 215 + ], + "type": "text", + "content": "based meta-learning task. In each episode, we randomly sample an image and a class set. The meta-learning task is to make the model learn to detect all appeared classes of the sampled class set on the image. To achieve this, we train the decoder to directly predict class-specific boxes with class-specific queries as input, under the supervision of our meta-contrastive learning that contains three different heads. We conduct extensive experiments on the benchmark datasets MSCOCO and PASCAL VOC. Experimental results show that our method outperforms the existing ZSD methods. In the future, we will focus on further performance improvement." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 216, + 288, + 252 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 216, + 288, + 252 + ], + "spans": [ + { + "bbox": [ + 47, + 216, + 288, + 252 + ], + "type": "text", + "content": "Acknowledgement. Jihong Guan was supported by National Natural Science Foundation of China (NSFC) under grant No. U1936205." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 262, + 107, + 274 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 262, + 107, + 274 + ], + "spans": [ + { + "bbox": [ + 48, + 262, + 107, + 274 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 281, + 288, + 712 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 53, + 281, + 287, + 335 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 281, + 287, + 335 + ], + "spans": [ + { + "bbox": [ + 53, + 281, + 287, + 335 + ], + "type": "text", + "content": "[1] Zeynep Akata, Florent Perronnin, Zaid Harchaoui, and Cordelia Schmid. Label-embedding for attribute-based classification. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 819–826, 2013. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 337, + 288, + 380 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 337, + 288, + 380 + ], + "spans": [ + { + "bbox": [ + 53, + 337, + 288, + 380 + ], + "type": "text", + "content": "[2] Ankan Bansal, Karan Sikka, Gaurav Sharma, Rama Chellappa, and Ajay Divakaran. Zero-shot object detection. In Proceedings of the European Conference on Computer Vision (ECCV), pages 384-400, 2018. 1, 2, 6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 381, + 287, + 414 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 381, + 287, + 414 + ], + "spans": [ + { + "bbox": [ + 53, + 381, + 287, + 414 + ], + "type": "text", + "content": "[3] Ankan Bansal, Karan Sikka, Gaurav Sharma, Rama Chellappa, and Ajay Divakaran. Zero-shot object detection. In ECCV, pages 384-400, 2018. 7" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 415, + 287, + 480 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 415, + 287, + 480 + ], + "spans": [ + { + "bbox": [ + 53, + 415, + 287, + 480 + ], + "type": "text", + "content": "[4] Maxime Bucher, Stéphane Herbin, and Frédéric Jurie. Improving semantic embedding consistency by metric learning for zero-shot classification. In Computer Vision-ECCV 2016: 14th European Conference, Amsterdam, The Netherlands, October 11-14, 2016, Proceedings, Part V 14, pages 730-746. Springer, 2016. 2" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 481, + 287, + 546 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 481, + 287, + 546 + ], + "spans": [ + { + "bbox": [ + 53, + 481, + 287, + 546 + ], + "type": "text", + "content": "[5] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part I 16, pages 213-229. Springer, 2020. 2" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 547, + 287, + 602 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 547, + 287, + 602 + ], + "spans": [ + { + "bbox": [ + 53, + 547, + 287, + 602 + ], + "type": "text", + "content": "[6] Shiming Chen, Wenjie Wang, Beihao Xia, Qinmu Peng, Xinge You, Feng Zheng, and Ling Shao. Free: Feature refinement for generalized zero-shot learning. In Proceedings of the IEEE/CVF international conference on computer vision, pages 122-131, 2021. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 602, + 287, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 602, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 53, + 602, + 287, + 635 + ], + "type": "text", + "content": "[7] Berkan Demirel, Ramazan Gokberk Cinbis, and Nazli Ikizler-Cinbis. Zero-shot object detection by hybrid region embedding. arXiv preprint arXiv:1805.06157, 2018. 1, 2, 6" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 636, + 287, + 669 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 636, + 287, + 669 + ], + "spans": [ + { + "bbox": [ + 53, + 636, + 287, + 669 + ], + "type": "text", + "content": "[8] Berkan Demirel, Ramazan Gokberk Cinbis, and Nazli Ikizler-Cinbis. Zero-shot object detection by hybrid region embedding. In BMVC, 2018. 6" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 53, + 670, + 287, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 670, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 53, + 670, + 287, + 712 + ], + "type": "text", + "content": "[9] Mark Everingham, Luc Van Gool, Christopher KI Williams, John Winn, and Andrew Zisserman. The pascal visual object classes (voc) challenge. International journal of computer vision, 88:303-308, 2009. 6" + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 26, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 139 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 139 + ], + "type": "text", + "content": "[10] Yanwei Fu, Timothy M Hospedales, Tao Xiang, Zhenyong Fu, and Shaogang Gong. Transductive multi-view embedding for zero-shot recognition and annotation. In Computer Vision-ECCV 2014: 13th European Conference, Zurich, Switzerland, September 6-12, 2014, Proceedings, Part II 13, pages 584-599. Springer, 2014. 2" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 307, + 141, + 545, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 141, + 545, + 173 + ], + "spans": [ + { + "bbox": [ + 307, + 141, + 545, + 173 + ], + "type": "text", + "content": "[11] Ross Girshick. Fast r-cnn. In Proceedings of the IEEE international conference on computer vision, pages 1440-1448, 2015. 2" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 176, + 545, + 231 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 176, + 545, + 231 + ], + "spans": [ + { + "bbox": [ + 307, + 176, + 545, + 231 + ], + "type": "text", + "content": "[12] Dikshant Gupta, Aditya Anantharaman, Nehal Mamgain, Vineeth N Balasubramanian, CV Jawahar, et al. A multi-space approach to zero-shot object detection. In Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision, pages 1209-1217, 2020. 1, 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 233, + 545, + 287 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 233, + 545, + 287 + ], + "spans": [ + { + "bbox": [ + 307, + 233, + 545, + 287 + ], + "type": "text", + "content": "[13] Zongyan Han, Zhenyong Fu, and Jian Yang. Learning the redundancy-free features for generalized zero-shot object recognition. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 12865-12874, 2020. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 290, + 545, + 344 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 290, + 545, + 344 + ], + "spans": [ + { + "bbox": [ + 307, + 290, + 545, + 344 + ], + "type": "text", + "content": "[14] Nasir Hayat, Munawar Hayat, Shafin Rahman, Salman Khan, Syed Waqas Zamir, and Fahad Shahbaz Khan. Synthesizing the unseen for zero-shot object detection. In Proceedings of the Asian Conference on Computer Vision, 2020. 1, 2, 6" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 347, + 545, + 390 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 347, + 545, + 390 + ], + "spans": [ + { + "bbox": [ + 307, + 347, + 545, + 390 + ], + "type": "text", + "content": "[15] Nasir Hayat, Munawar Hayat, Shafin Rahman, Salman Khan, Syed Waqas Zamir, and Fahad Shahbaz Khan. Synthesizing the unseen for zero-shot object detection. In ACCV, 2020. 6, 7" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 393, + 545, + 437 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 393, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 307, + 393, + 545, + 437 + ], + "type": "text", + "content": "[16] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 770-778, 2016. 6" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 439, + 545, + 493 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 439, + 545, + 493 + ], + "spans": [ + { + "bbox": [ + 307, + 439, + 545, + 493 + ], + "type": "text", + "content": "[17] Peiliang Huang, Junwei Han, De Cheng, and Dingwen Zhang. Robust region feature synthesizer for zero-shot object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 7622-7631, 2022. 1, 2, 6, 7" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 496, + 545, + 550 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 496, + 545, + 550 + ], + "spans": [ + { + "bbox": [ + 307, + 496, + 545, + 550 + ], + "type": "text", + "content": "[18] Siddhesh Khandelwal, Anirudth Nambirajan, Behjat Siddique, Jayan Eledath, and Leonid Sigal. Frustratingly simple but effective zero-shot detection and segmentation: Analysis and a strong baseline. arXiv preprint arXiv:2302.07319, 2023. 1, 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 553, + 545, + 597 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 553, + 545, + 597 + ], + "spans": [ + { + "bbox": [ + 307, + 553, + 545, + 597 + ], + "type": "text", + "content": "[19] Dahun Kim, Tsung-Yi Lin, Anelia Angelova, In So Kweon, and Weicheng Kuo. Learning open-world object proposals without learning to classify. IEEE Robotics and Automation Letters, 7(2):5453-5460, 2022. 1" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 599, + 545, + 621 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 599, + 545, + 621 + ], + "spans": [ + { + "bbox": [ + 307, + 599, + 545, + 621 + ], + "type": "text", + "content": "[20] Diederik P Kingma and Max Welling. Auto-encoding variational bayes. arXiv preprint arXiv:1312.6114, 2013. 2" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 624, + 545, + 667 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 624, + 545, + 667 + ], + "spans": [ + { + "bbox": [ + 307, + 624, + 545, + 667 + ], + "type": "text", + "content": "[21] Elyor Kodirov, Tao Xiang, and Shaogang Gong. Semantic autoencoder for zero-shot learning. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 3174-3183, 2017. 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 669, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 669, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 669, + 545, + 712 + ], + "type": "text", + "content": "[22] Zhihui Li, Lina Yao, Xiaoqin Zhang, Xianzhi Wang, Salil Kanhere, and Huaxiang Zhang. Zero-shot object detection with textual descriptions. In AAAI, volume 33, pages 8690-8697, 2019. 7" + } + ] + } + ], + "index": 25 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6853" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[23] Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dólár. Focal loss for dense object detection. In Proceedings of the IEEE international conference on computer vision, pages 2980-2988, 2017. 2, 3, 5" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 118, + 287, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 118, + 287, + 184 + ], + "spans": [ + { + "bbox": [ + 48, + 118, + 287, + 184 + ], + "type": "text", + "content": "[24] Tsung-Yi Lin, Michael Maire, Serge Belongie, James Hays, Pietro Perona, Deva Ramanan, Piotr Dólár, and C Lawrence Zitnick. Microsoft coco: Common objects in context. In Computer Vision-ECCV 2014: 13th European Conference, Zurich, Switzerland, September 6-12, 2014, Proceedings, Part V 13, pages 740-755. Springer, 2014. 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 185, + 288, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 185, + 288, + 228 + ], + "spans": [ + { + "bbox": [ + 48, + 185, + 288, + 228 + ], + "type": "text", + "content": "[25] Qiaomei Mao, Chong Wang, Shenghao Yu, Ye Zheng, and Yuqi Li. Zero-shot object detection with attributes-based category similarity. IEEE Transactions on Circuits and Systems II: Express Briefs, 67(5):921-925, 2020. 1, 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 230, + 288, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 230, + 288, + 274 + ], + "spans": [ + { + "bbox": [ + 48, + 230, + 288, + 274 + ], + "type": "text", + "content": "[26] Tomas Mikolov, Edouard Grave, Piotr Bojanowski, Christian Puhrsch, and Armand Joulin. Advances in pretraining distributed word representations. arXiv preprint arXiv:1712.09405, 2017. 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 275, + 288, + 341 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 275, + 288, + 341 + ], + "spans": [ + { + "bbox": [ + 48, + 275, + 288, + 341 + ], + "type": "text", + "content": "[27] Sanath Narayan, Akshita Gupta, Fahad Shahbaz Khan, Cees GM Snoek, and Ling Shao. Latent embedding feedback and discriminative features for zero-shot classification. In Computer Vision-ECCV 2020: 16th European Conference, Glasgow, UK, August 23-28, 2020, Proceedings, Part XXII 16, pages 479-495. Springer, 2020. 1, 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 342, + 287, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 342, + 287, + 374 + ], + "spans": [ + { + "bbox": [ + 48, + 342, + 287, + 374 + ], + "type": "text", + "content": "[28] Aaron van den Oord, Yazhe Li, and Oriol Vinyals. Representation learning with contrastive predictive coding. arXiv preprint arXiv:1807.03748, 2018. 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 376, + 287, + 420 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 376, + 287, + 420 + ], + "spans": [ + { + "bbox": [ + 48, + 376, + 287, + 420 + ], + "type": "text", + "content": "[29] Shafin Rahman, Salman Khan, and Nick Barnes. Improved visual-semantic alignment for zero-shot object detection. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 11932–11939, 2020. 6" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 421, + 287, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 421, + 287, + 453 + ], + "spans": [ + { + "bbox": [ + 48, + 421, + 287, + 453 + ], + "type": "text", + "content": "[30] Shafin Rahman, Salman Khan, and Nick Barnes. Improved visual-semantic alignment for zero-shot object detection. In AAAI, volume 34, pages 11932–11939, 2020. 6, 7" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 455, + 287, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 455, + 287, + 498 + ], + "spans": [ + { + "bbox": [ + 48, + 455, + 287, + 498 + ], + "type": "text", + "content": "[31] Shafin Rahman, Salman Khan, and Fatih Porikli. Zero-shot object detection: Learning to simultaneously recognize and localize novel concepts. In ACCV, pages 547-563. Springer, 2018. 6" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 500, + 287, + 544 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 500, + 287, + 544 + ], + "spans": [ + { + "bbox": [ + 48, + 500, + 287, + 544 + ], + "type": "text", + "content": "[32] Shafin Rahman, Salman H Khan, and Fatih Porikli. Zero-shot object detection: Joint recognition and localization of novel concepts. International Journal of Computer Vision, 128:2979-2999, 2020. 1, 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 545, + 287, + 589 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 545, + 287, + 589 + ], + "spans": [ + { + "bbox": [ + 48, + 545, + 287, + 589 + ], + "type": "text", + "content": "[33] Joseph Redmon, Santosh Divvala, Ross Girshick, and Ali Farhadi. You only look once: Unified, real-time object detection. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 779-788, 2016. 2" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 590, + 287, + 623 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 590, + 287, + 623 + ], + "spans": [ + { + "bbox": [ + 48, + 590, + 287, + 623 + ], + "type": "text", + "content": "[34] Shaoqing Ren, Kaiming He, Ross Girshick, and Jian Sun. Faster r-cnn: Towards real-time object detection with region proposal networks. In NIPS, 2015. 1" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 624, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 624, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 624, + 287, + 689 + ], + "type": "text", + "content": "[35] Hamid Rezatofighi, Nathan Tsoi, JunYoung Gwak, Amir Sadeghian, Ian Reid, and Silvio Savarese. Generalized intersection over union: A metric and a loss for bounding box regression. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 658-666, 2019. 3, 5" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 713 + ], + "type": "text", + "content": "[36] Edgar Schonfeld, Sayna Ebrahimi, Samarth Sinha, Trevor Darrell, and Zeynep Akata. Generalized zero-and few-shot" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 688 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 106 + ], + "type": "text", + "content": "learning via aligned variational autoencoders. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 8247-8255, 2019. 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 107, + 545, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 162 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 162 + ], + "type": "text", + "content": "[37] Flood Sung, Yongxin Yang, Li Zhang, Tao Xiang, Philip HS Torr, and Timothy M Hospedales. Learning to compare: Relation network for few-shot learning. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1199-1208, 2018. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 163, + 545, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 163, + 545, + 206 + ], + "spans": [ + { + "bbox": [ + 307, + 163, + 545, + 206 + ], + "type": "text", + "content": "[38] Yongqin Xian, Tobias Lorenz, Bernt Schiele, and Zeynep Akata. Feature generating networks for zero-shot learning. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 5542-5551, 2018. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 208, + 545, + 261 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 208, + 545, + 261 + ], + "spans": [ + { + "bbox": [ + 307, + 208, + 545, + 261 + ], + "type": "text", + "content": "[39] Yongqin Xian, Saurabh Sharma, Bernt Schiele, and Zeynep Akata. f-vaegan-d2: A feature generating framework for any-shot learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 10275–10284, 2019. 2" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 263, + 545, + 316 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 263, + 545, + 316 + ], + "spans": [ + { + "bbox": [ + 308, + 263, + 545, + 316 + ], + "type": "text", + "content": "[40] Caixia Yan, Xiaojun Chang, Minnan Luo, Huan Liu, Xiaoqin Zhang, and Qinghua Zheng. Semantics-guided contrastive network for zero-shot object detection. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2022. 1, 2, 6, 7" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 319, + 545, + 373 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 319, + 545, + 373 + ], + "spans": [ + { + "bbox": [ + 307, + 319, + 545, + 373 + ], + "type": "text", + "content": "[41] Caixia Yan, Qinghua Zheng, Xiaojun Chang, Minnan Luo, Chung-Hsing Yeh, and Alexander G Hauptman. Semantics-preserving graph propagation for zero-shot object detection. IEEE Transactions on Image Processing, 29:8163-8176, 2020. 1, 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 375, + 545, + 430 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 375, + 545, + 430 + ], + "spans": [ + { + "bbox": [ + 307, + 375, + 545, + 430 + ], + "type": "text", + "content": "[42] Shizhen Zhao, Changxin Gao, Yuanjie Shao, Lerenhan Li, Changqian Yu, Zhong Ji, and Nong Sang. Gtnet: Generative transfer network for zero-shot object detection. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 34, pages 12967-12974, 2020. 1, 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 431, + 545, + 464 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 431, + 545, + 464 + ], + "spans": [ + { + "bbox": [ + 307, + 431, + 545, + 464 + ], + "type": "text", + "content": "[43] Ye Zheng and Li Cui. Zero-shot object detection with transformers. In 2021 IEEE International Conference on Image Processing (ICIP), pages 444-448. IEEE, 2021. 2, 7" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 465, + 545, + 508 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 465, + 545, + 508 + ], + "spans": [ + { + "bbox": [ + 307, + 465, + 545, + 508 + ], + "type": "text", + "content": "[44] Ye Zheng, Ruoran Huang, Chuanqi Han, Xi Huang, and Li Cui. Background learnable cascade for zero-shot object detection. In Proceedings of the Asian Conference on Computer Vision, 2020. 1, 2" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 510, + 545, + 542 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 510, + 545, + 542 + ], + "spans": [ + { + "bbox": [ + 307, + 510, + 545, + 542 + ], + "type": "text", + "content": "[45] Ye Zheng, Ruoran Huang, Chuanqi Han, Xi Huang, and Li Cui. Background learnable cascade for zero-shot object detection. In ACCV, 2020. 6, 7" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 544, + 545, + 586 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 544, + 545, + 586 + ], + "spans": [ + { + "bbox": [ + 307, + 544, + 545, + 586 + ], + "type": "text", + "content": "[46] Ye Zheng, Jiahong Wu, Yongqiang Qin, Faen Zhang, and Li Cui. Zero-shot instance segmentation. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 2593-2602, 2021. 2" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 588, + 545, + 642 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 588, + 545, + 642 + ], + "spans": [ + { + "bbox": [ + 307, + 588, + 545, + 642 + ], + "type": "text", + "content": "[47] Pengkai Zhu, Hanxiao Wang, and Venkatesh Saligrama. Don't even look once: Synthesizing features for zero-shot detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11693-11702, 2020. 1, 2" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 643, + 545, + 688 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 643, + 545, + 688 + ], + "spans": [ + { + "bbox": [ + 307, + 643, + 545, + 688 + ], + "type": "text", + "content": "[48] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable " + }, + { + "bbox": [ + 307, + 643, + 545, + 688 + ], + "type": "inline_equation", + "content": "\\{\\mathrm{detr}\\}" + }, + { + "bbox": [ + 307, + 643, + 545, + 688 + ], + "type": "text", + "content": ": Deformable transformers for end-to-end object detection. In International Conference on Learning Representations, 2021. 2, 6" + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "6854" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/5204095b-1c9c-4150-9f9c-b1c27fdd82da_content_list.json b/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/5204095b-1c9c-4150-9f9c-b1c27fdd82da_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..ee80a4f5f1a17d69c7609f3cd99c3b9f7ac89569 --- /dev/null +++ b/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/5204095b-1c9c-4150-9f9c-b1c27fdd82da_content_list.json @@ -0,0 +1,1444 @@ +[ + { + "type": "text", + "text": "MetaBEV: Solving Sensor Failures for 3D Detection and Map Segmentation", + "text_level": 1, + "bbox": [ + 102, + 130, + 866, + 154 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Chongjian Ge $^{1*}$ Junsong Chen $^{3,1*}$ Enze Xie $^{2\\dagger}$ Zhongdao Wang $^{2}$", + "bbox": [ + 223, + 178, + 740, + 198 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Lanqing Hong² Huchuan Lu³ Zhenguo Li² Ping Luo¹,⁴†", + "bbox": [ + 254, + 198, + 712, + 217 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1The University of Hong Kong 2Huawei Noah's Ark Lab", + "bbox": [ + 250, + 219, + 720, + 237 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{3}$ Dalian University of Technology $^{4}$ Shanghai AI Laboratory", + "bbox": [ + 250, + 237, + 720, + 255 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "rhettgee $@$ connect.hku.hk jschen@mail.dlut.edu.cn lhchuan@dlut.edu.cn", + "bbox": [ + 173, + 258, + 795, + 272 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{xie.enze, wangzhongdao, honglanqing, li.zhenguo}@huawei.com pluo@cs.hku.hk", + "bbox": [ + 161, + 275, + 808, + 290 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Project page: https://chongjiange.github.io/metabev.html", + "bbox": [ + 254, + 292, + 712, + 308 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/d22cc19f55915b84edf7a6856dd242f5f43ce0741ea6e2f353a506f4b9bc47ff.jpg", + "image_caption": [ + "Figure 1. Selected 3D prediction results under various sensor failures. MetaBEV shows stronger robustness on both map segmentation and 3D detection compared to the representative multi-modal method, e.g., BEVFusion [25]. Notably, in case of an entire sensor absent (e.g., Camera or LiDAR), MetaBEV provides satisfactory outcomes while existing methods fail to. Top two rows: 3D prediction results. Bottom row: the corresponding ground truths." + ], + "image_footnote": [], + "bbox": [ + 81, + 316, + 890, + 523 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 611, + 313, + 627 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Perception systems in modern autonomous driving vehicles typically take inputs from complementary multi-modal sensors, e.g., LiDAR and cameras. However, in real-world applications, sensor corruptions and failures lead to inferior performances, thus compromising autonomous safety. In this paper, we propose a robust framework, called MetaBEV, to address extreme real-world environments, involving overall six sensor corruptions and two extreme sensor-missing situations. In MetaBEV, signals from multiple sensors are first processed by modal-specific encoders. Subsequently, a set of dense BEV queries are initialized, termed meta-BEV. These queries are then processed iteratively by a BEV-Evolving decoder, which selectively aggregates deep features from either LiDAR, cameras, or both", + "bbox": [ + 75, + 645, + 470, + 857 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "modalities. The updated BEV representations are further leveraged for multiple 3D prediction tasks. Additionally, we introduce a new $M^2 oE$ structure to alleviate the performance drop on distinct tasks in multi-task joint learning. Finally, MetaBEV is evaluated on the nuScenes dataset with 3D object detection and BEV map segmentation tasks. Experiments show MetaBEV outperforms prior arts by a large margin on both full and corrupted modalities. For instance, when the LiDAR signal is missing, MetaBEV improves $35.5\\%$ detection NDS and $17.7\\%$ segmentation mIoU upon the vanilla BEVFusion [25] model; and when the camera signal is absent, MetaBEV still achieves $69.2\\%$ NDS and $53.7\\%$ mIoU, which is even higher than previous works that perform on full-modalities. Moreover, MetaBEV performs moderately against previous methods in both canonical perception and multi-task learning settings, refreshing state-of-the-art nuScenes BEV map segmentation with $70.4\\%$ mIoU.", + "bbox": [ + 500, + 612, + 892, + 869 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "$^{0}*$ Equal contribution.", + "bbox": [ + 93, + 875, + 215, + 887 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "$^{0}\\dagger$ Corresponding authors.", + "bbox": [ + 96, + 887, + 236, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "8721", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 89, + 209, + 106 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Perceiving the surrounding environment is a fundamental capability of autonomous driving systems. In pursuit of higher perceptual accuracy, prior works make significant efforts in designing stronger task-specific modules [41, 16, 21], cultivating effective training paradigms [5], leveraging multi-modalities [25, 22, 7], etc. Among all these, the multi-sensors fusion strategy exhibits significant advantages in achieving stronger perception abilities [31, 39, 25, 1], thus being widely explored in both academia and industry. While the majority of works focus on achieving optimal performance on ideal multi-modal inputs for a single specific task, they unintentionally neglect how the designed models perform with sensor failures, which are commonly encountered and inevitable in real-world applications.", + "bbox": [ + 75, + 114, + 468, + 325 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To alleviate performance drop on sensor failures, previous works encounter two challenges as follows. 1) Features misalignment: Existing fusion methods typically utilize CNNs and features concatenation for fusion [25, 22]. The pixel-level position correlation is consistently imposed, giving rise to multi-modal features misalignment, especially when geometric-related noises are introduced. This issue could be attributed to the intrinsic characteristics of CNNs, which exhibit limitations in long-range perception and adaptive attention to input features. 2) Heavily reliant on complete modalities: Prior arts generate the fused BEV features using either query-indexing or channel-wise fusion manners. Query-indexing methods [29, 31, 32, 14] typically rely on LiDAR and 2D Camera features for mutual querying, while channel-wise fusion approaches [25, 22] are inevitable to involve element-wise operations (e.g. element-sum) for feature merging. Both fusion strategies are heavily dependent on complete modality inputs and lead to inferior perception performance encountering extreme sensor failures such as LiDAR-missing or Cameras-missing, thus being limited in the practical applications.", + "bbox": [ + 75, + 325, + 470, + 643 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this research, we propose MetaBEV to tackle the above features misalignment and full-modality dependence problems through modality-arbitrary and task-agnostic learning in the unified bird's-eye view (BEV) representation space [18]. We identify the major bottleneck in modality-dependent methods is the lack of designs that enable independent fusion of different modalities by the fusion module. Therefore, we present a modality-arbitrary BEV-Evolving decoder, which leverages cross-modal attention to correlate the learnable meta-BEV queries with either a single camera-BEV feature, LiDAR-BEV feature, or both to eliminate the bottleneck. Finally, we apply a few task-specific heads to support different 3D perception predictions.", + "bbox": [ + 75, + 643, + 468, + 839 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Except for the canonical perception (on no corrupted sensors), we also evaluate MetaBEV on overall six sensor corruptions (Limited Field (LF), Beams Reduction (BR), Missing Objects (MO), View Drop (VD), View Noise (VN),", + "bbox": [ + 75, + 839, + 468, + 901 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/03880d9e863487a61412f4b354f6d57ee44cc5a52e7c41df2dbd8a9c9d1ca746.jpg", + "image_caption": [ + "Figure 2. MetaBEV shows stronger robustness on missing sensors. We perform representative methods with full/missing modalities on both map segmentation (the left part) and 3D detection (the right part). Results show MetaBEV can mitigate the performance drop on input absence. Quantitatively, when facing missing cameras, MetaBEV still achieves $53.7\\%$ mIoU, which outperforms the representative method (i.e., BEVFusion [25]), by $+49.6\\%$ mIoU, and is even better than MVP [39] performed on full-modalities. The superior performance could also be found on 3D detection tasks." + ], + "image_footnote": [], + "bbox": [ + 504, + 92, + 885, + 223 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Obstacle Occlusion (OO)) and two sensor-missing scenarios (Missing LiDAR (ML) and Missing Camera (MC)). Compared with prior works, MetaBEV performs more robustly as depicted in Fig. 1. For example, it achieves $69.2\\%$ NDS and $42.6\\%$ NDS on detection when totally missing the cameras or LiDAR, respectively. For map segmentation, when total cameras absence occurs, MetaBEV could still achieve better performance compared to the work trained on multi-modalities (i.e., $54.7\\%$ v.s. MVP's $49.0\\%$ mIoU [39]). Besides, the attention-based MetaBEV exhibits inherent robustness against multiple heavy corruptions with zero-shot and in-domain tests. For instance, as shown in Tab. 3, even missing $66.6\\%$ of LiDAR points, MetaBEV still achieves $55\\%$ NDS, outperforming the competitor by $+11.7\\%$ .", + "bbox": [ + 496, + 404, + 890, + 616 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Moreover, considering the limited computational resource in practice, using a single framework with shared parameters for different tasks is more efficient than using separate frameworks for multiple tasks. However, the task conflicts in the joint learning of detection and segmentation often lead to severe performance drop [36, 21, 25], and existing methods rarely analyze and design for multi-task learning (MTL). We incorporate MetaBEV with a flexible module based on Multi-Task Mixture of Experts $(\\mathbf{M}^2\\mathrm{oE})$ to demonstrate one possible solution for MTL and hope to stimulate further research in this area.", + "bbox": [ + 496, + 616, + 890, + 781 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The appealing advantages of MetaBEV are concluded:", + "bbox": [ + 517, + 782, + 880, + 797 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "1. MetaBEV is a novel BEV perception framework for 3D object detection and BEV map segmentation, which can maintain resilient performance under arbitrary sensor input. Plenty of real-world sensor corruptions are formulated as well as methodically experimented with and analyzed to verify its robustness.", + "bbox": [ + 513, + 809, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "8722", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "2. MetaBEV involves the $\\mathbf{M}^2\\mathrm{oE}$ structures to alleviate tasks conflict when performing 3D detection and segmentation tasks with the same trained weights.", + "3. MetaBEV achieves state-of-the-art performance on nuScenes dataset [3]. It's the first method designed for both sensor failures and tasks conflict. We hope MetaBEV will facilitate future research." + ], + "bbox": [ + 88, + 89, + 467, + 207 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 76, + 223, + 217, + 238 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.1. LiDAR-Camera Fusion", + "text_level": 1, + "bbox": [ + 76, + 248, + 292, + 263 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In 3D perception tasks, the effectiveness of multi-sensor fusion is notable. Therefore, researchers have focused on better combining geometric-centric point clouds and semantic-centric images. Existing methods mainly focus on three aspects: proposal-level [6], point-level [7, 1, 19], and feature-level [25, 22]. While attempting to combine multiple modalities, existing approaches typically adopt similar fusion strategies, including query-indexing fusion [1] and channel-wise fusion [25, 22]. Though showing effective in full-modality input, the above fusion manners usually associate multi-modal features tightly among points or pixels, causing features in these methods to be susceptible to spatial misalignment issues and suffering from system collapses due to sensor missing. In our work, we explore an approach that can handle arbitrary modality freely to mitigate the above limitations.", + "bbox": [ + 76, + 272, + 467, + 513 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Sensors-Failure Perception", + "text_level": 1, + "bbox": [ + 76, + 525, + 318, + 540 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Sensor failures can significantly impact the accuracy of 3D perception, thereby jeopardizing the safety of autonomous driving. Therefore, conducting research on sensor failures is of utmost practical importance. Prior arts have made preliminary attempts to propose robust frameworks that address specific sensor failure scenarios on a case-by-case basis. These scenarios include camera-views drop [1], changes in illumination conditions [25, 7, 1], noisy inputs [20], and etc. More recently, [40] provided a comprehensive benchmark for verifying the robustness of methods mainly on sensor degradation. While previous works mainly focus on sensor corruptions, sensor absence is rarely noticed. In this work, we propose a novel perception framework that analyzes not only the aspects of sensor corruptions but also sensor absence comprehensively.", + "bbox": [ + 76, + 549, + 467, + 775 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.3. Multi-Task Learning", + "text_level": 1, + "bbox": [ + 76, + 786, + 272, + 801 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Multi-task learning denotes performing multiple task predictions with one set of trained weights, which appeals to the research community for its practical values, such as the complementary performance, less computational cost, etc. However, multi-task learning can also be challenging, as the model must learn to balance various objectives of", + "bbox": [ + 76, + 810, + 467, + 898 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "each task and avoid tasks conflict. In 3D perception, the tasks conflict has been proven by $\\mathbf{M}^2\\mathrm{BEV}$ [36] and BEVFormer [21], which both perform joint training on camera-only 3D object detection and BEV map segmentation. It is empirically found that joint training leads to severe accuracy degradation on each single task. Prior arts do not address the issues effectively due to their unified models and usually solve the problems from the learning perspective. For example, UniAD [13] adopts multiple training stages to adjust the overall network module by module to avoid gradient conflicts in multi-task learning, which is not end-to-end and can not be optimized layer-by-layer to adjust gradients. Inspired by Mixture-of-Expert (MoE), which is specially designed for large language model in the Natural Language Processing [35, 17, 15, 37, 33] and self-supervised field [8, 11, 12, 10], we introduce a robust fusion module with a new $\\mathbf{M}^2\\mathrm{oE}$ -FFN layer. The main purpose is to mitigate the gradient conflict between detection and segmentation to achieve a more balanced performance. MetaBEV is the first framework introducing MoE into 3D object detection and BEV map segmentation as a multi-modal, multitask, and robust approach.", + "bbox": [ + 496, + 90, + 890, + 422 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. MetaBEV Method", + "text_level": 1, + "bbox": [ + 500, + 435, + 678, + 450 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We introduce a new baseline, which targets solving a range of sensor failures on 3D object detection and BEV map segmentation tasks. As opposed to existing perception methods that heavily rely on the complete sensor inputs, we connect different modalities through a parameterized metaBEV query and perform cross-modal attention to integrate both semantic and geometry representations from cameras and LiDAR. As shown in Figure 3, the overall pipeline consists of a multi-modalities feature encoder, a BEV-Evolving decoder with cross-modal deformable attention, and task-specific heads. Architecture designs are detailed as follows.", + "bbox": [ + 496, + 460, + 890, + 627 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. BEV Feature Encoder Overview", + "text_level": 1, + "bbox": [ + 500, + 636, + 782, + 650 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "MetaBEV generates fused features in the BEV space, as BEV representation provides a solution to combine image features with insufficient geometric knowledge and Li-DAR features lacking semantic understanding in a unified domain, allowing for complementary fusion. Additionally, the regularity of the BEV feature facilitates the effective integration of various advanced task heads, which could benefit plenty of perception tasks.", + "bbox": [ + 496, + 659, + 890, + 779 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Camera/LiDAR to BEV. We build our multi-modal feature encoder based on the state-of-the-art perception method BEVFusion [25], which takes multi-view-images and LiDAR-points pair as input and transforms the camera features into BEV space with depth prediction and geometric projection, respectively. Specifically, we adopt a camera backbone $\\phi_c(\\cdot)$ to generate $N$ -view 2D image representations $F_{c}^{i}, i \\in [1,2,\\dots ,N]$ . Then, following LSS [27], we", + "bbox": [ + 496, + 779, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "8723", + "bbox": [ + 480, + 945, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/9fc992a5b13f3c12e2bb80e36fe0b5af602b4905e0ab32f6a1225262e4717f6a.jpg", + "image_caption": [ + "Figure 3. An overview of MetaBEV framework. The multi-modal inputs are separately processed by the camera encoder $\\phi_c(\\cdot)$ and LiDAR encoder $\\phi_l(\\cdot)$ to produce the BEV representations $B_{c}, B_{l}$ . To generate the fused BEV features, a BEV-Evolving decoder takes multi-modal BEV representations and an externally initialized meta-BEV feature (as a query feature) for correlation computation. Task-specific heads take the fused features for 3D detection." + ], + "image_footnote": [], + "bbox": [ + 99, + 89, + 872, + 250 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "scatter the dense feature $F_{c}^{i}$ into discrete 3D space and compress the generated 3D voxel features $V_{c} \\in \\mathbb{R}^{D \\times C \\times X \\times Y}$ into the camera BEV representations $B_{c} \\in \\mathbb{R}^{C \\times X \\times Y}$ with the pillar format [25], where $D, C, (X, Y)$ denote the depth, dimension and spatial resolution of BEV feature, respectively. As for the LiDAR points, voxelization and sparse 3D convolutions $\\phi_{l}(\\cdot)$ are utilized for encoding LiDAR BEV representation $B_{l}$ .", + "bbox": [ + 75, + 334, + 468, + 455 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Subsequently, Previous works [25, 22] usually involve concatenating and CNN-based feature fusion, which may cause significant performance drop under sensor corruptions or even system collapse when sensor failures occur. As mentioned in Sec. 1, CNNs exhibit limited effectiveness in large-corruption of input modality (due to the local-aggregation characteristic) and are inappropriate to deal with the absent input modality caused by sensor missing (due to the weight-sharing modeling). We solve the above challenges by introducing BEV-Evolving Decoder as follows.", + "bbox": [ + 75, + 455, + 470, + 619 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. BEV-Evolving Decoder", + "text_level": 1, + "bbox": [ + 76, + 633, + 290, + 648 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The BEV-Evolving decoder consists of three key components: the cross-modal attention layers, the self-attention layers, and the plug-and-play $\\mathbf{M}^2\\mathrm{oE}$ blocks. The above two components facilitate fusing arbitrary modalities, while the $\\mathbf{M}^2\\mathrm{oE}$ blocks are designed for mitigating the tasks conflict. Cross-Modal Attention Layer. We first initialize a set of dense BEV queries, each representing the feature within a specific spatial grid, termed meta-BEV $(B_{m})$ . $B_{m}$ is added with position embeddings (PE) and then correlates with either a camera BEV feature $(B_{c})$ , LiDAR BEV feature $(B_{l})$ or both. To improve the computational efficiency, we adopt deformable attention $\\mathrm{DAttn}(\\cdot)$ [43]. However, the original implementation $\\mathrm{DAttn}(\\cdot)$ is not suitable for processing arbitrary inputs, as it utilizes one unified MLP layer to sample reference points $\\Delta p$ and attention weights $A$ . We then introduce model-specific MLP layers (i.e., C-MLP for cameras", + "bbox": [ + 75, + 657, + 468, + 900 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "and L-MLP for LiDAR in Fig. 4 III) for the flexibility of fusion. Given any input BEV representations $x \\in [B_c, B_l]$ as value features, we first generate model-specific sampling offsets $\\Delta p^x$ and attention weights $A^x$ from query $B_m$ . We then combine the pixel coordinates of $B_m$ and the corresponding offsets $\\Delta p^x$ to locate the sampled value features. After re-scaling the sampled features by the attention weights $A^x$ , meta-BEV is updated from informative sensor features. The overall process is formulated in the following,", + "bbox": [ + 496, + 334, + 893, + 470 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathrm {D A t t n} \\left(B _ {m}, p, x\\right) = \\\\ \\sum_ {m = 1} ^ {M} W _ {m} \\left[ \\sum_ {x \\in \\left[ B _ {c} \\cup B _ {l} \\right]} \\sum_ {k = 1} ^ {K} A _ {m k} ^ {x} \\cdot W _ {m} ^ {\\prime} x \\left(p + \\Delta p _ {m k} ^ {x}\\right) \\right], \\tag {1} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 517, + 489, + 890, + 553 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $m$ denotes the attention head, $K$ denotes the number of sampled keys, and $p$ denotes reference points. We use $W_{m}$ and $W_{m}^{\\prime}$ to represent the learnable projection matrixes. Note that in Eq. 1, the input feature $x$ could be either $B_{c}$ , $B_{l}$ , or both. It enables MetaBEV to flexibly utilize multimodal features for the deformable attention calculation during both training and testing.", + "bbox": [ + 496, + 566, + 890, + 672 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The cross-attention mechanism performs the fusion process layer by layer, enabling the meta-BEV to iteratively \"evolve\" into fused features that capture both semantic and geometric information from the cameras and LiDAR modalities, respectively. Note that we sequentially incorporate $N$ cross-modal attention layers to capture intercorrelations among the meta-BEV and diverse sensor features. Nonetheless, we have not yet explicitly modeled the intra-correlations, which refer to as the connection among different queries. Therefore, we introduce the self-attention layers to facilitate fused features capturing the intra-correlations. The details are discussed below.", + "bbox": [ + 496, + 672, + 890, + 853 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Self-Attention Layer. To construct the self-attention layer, we downgrade the modal-specific MLP into the unified MLP layer. Besides, to sufficiently model intra-correlations", + "bbox": [ + 496, + 854, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "8724", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/5cb87d87af221c5543b31a9abdf8fd382946bfaa7881bbc97681f2efde7f60f8.jpg", + "image_caption": [ + "Figure 4. Detailed illustration of a BEV-Evolving block. In the cross-modal deformable attention layer, We incorporate model-specific MLP layers to enable flexibly calculating sampling offsets and attention weights for an arbitrary modality. In FFN layer, we incorporate two MoE options to alleviate tasks conflict in multi-task learning." + ], + "image_footnote": [], + "bbox": [ + 86, + 89, + 493, + 252 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/5adb55498d328fea61124a012018c1c6099309c3d80f9b1b6c1cb37cea1dda91.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 495, + 90, + 880, + 252 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "among queries, the input feature $x$ in Eq. 1 is substituted by $B_{m}$ , resulting in a self-attention calculation $\\mathrm{DA}\\mathrm{attn}(B_m,p,B_m)$ . We assemble only $M = 2$ self-attention layers in the BEV-Evolving Decoder, achieving a favorable trade-off between performance and computational efficiency. By modeling inter-modalities and intra-queries correlations, the fused BEV features are finally output for 3D predictions. It's experimentally found that the hybrid designs, combining both intra- and inter-correlations, provide comprehensive modeling on the fused BEV features, thus benefiting various tasks (as validated in Sec. 4.5).", + "bbox": [ + 75, + 334, + 467, + 498 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "$\\mathbf{M}^2\\mathbf{o}\\mathbf{E}$ Block. As shown in Fig. 4 I and II, following the previous setting of [28] that is designed for large language modeling via a mixture of experts layers (MoE), we incorporate the MLP layer in our BEV-Evolving block with MoE to introduce our $\\mathbf{M}^2\\mathbf{o}\\mathbf{E}$ blocks for multi-task learning. We first illustrate the $\\mathrm{RM}^2\\mathrm{oE}$ (as shown in Fig. 4 I) with the following formulation,", + "bbox": [ + 75, + 500, + 467, + 604 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {M} ^ {2} \\mathrm {o E} (x) = \\sum_ {i = 1} ^ {t} \\mathcal {R} (x) _ {i} \\mathcal {E} _ {i} (x), t \\ll E \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 148, + 614, + 468, + 654 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $x \\in \\mathbb{R}^D$ is the input tokens to the $\\mathrm{RM}^2\\mathrm{oE}$ -FFN layer, $\\mathcal{R} : \\mathbb{R}^D \\to \\mathbb{R}^E$ is a routing function which assigns each token to its belonging experts and $\\mathcal{E}_i : \\mathbb{R}^D \\to \\mathbb{R}^D$ is the token processing in expert $i$ . Both $\\mathcal{E}_i$ and $\\mathcal{R}$ are implemented by MLP layers, and $E$ is a hyper-parameter as the total expert capacity. With sparse $\\mathcal{R}$ where top $t$ probability is selected, each token can only be routed to $t \\ll E$ experts, while a lot of experts remain inactive. Under the extreme condition of $t = 1$ , the additional calculation only comes from $\\mathcal{R}$ . For $\\mathrm{HM}^2\\mathrm{oE}$ , Fig. 4 II depicts a degenerate version when $E = \\text{task number}$ and $\\mathcal{R} = 1$ . In this scenario, tokens bypass the router allocation process and pass through the task-specific FFN networks before being merged by the task-fusion network. This super-linear scaling of the MLP layer facilitates multi-task training and inference by enabling the router to select appropriate experts. During network opti", + "bbox": [ + 75, + 657, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "mization, such a process mitigates tasks conflict between 3D object detection and BEV map segmentation by separating the conflicting gradients (caused by diverse training objectives) with different experts.", + "bbox": [ + 496, + 334, + 890, + 395 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.3. Sensor Failures", + "text_level": 1, + "bbox": [ + 500, + 405, + 653, + 419 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "A practical perception model is required to perform effectively even encountering corrupted or absent inputs. To this end, we define a series of sensor failures to simulate both sensor corruptions and complete sensor absence. For sensor corruptions, we include six types: 1) Limited Field of LiDAR (LF), which occurs when LiDAR data can only be collected from a portion of the field of view due to incorrect collection or partial hardware damage [40]; 2) Missing of Objects (MO), which appears when certain materials prevent some LiDAR points from being reflected [40]; 3) Beams Reduction (BR), occurring due to limited power supply or sensor processing capabilities; 4) View Drop (VD) and 5) View Noise (VN), resulting from camera faults; and 6) Obstacle Occlusion (OO), that is a real-world phenomenon where objects are occluded from the cameras. Furthermore, we evaluate MetaBEV using extreme sensor absence scenarios, including Missing Camera(MC) and Missing LiDAR(ML). As such, our evaluation takes into account both sensor corruptions and absence.", + "bbox": [ + 496, + 428, + 890, + 715 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.4. Switched Modality Training", + "text_level": 1, + "bbox": [ + 500, + 726, + 751, + 742 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The unique designs (i.e., modal-specific modules) in the BEV-Evolving block enable MetaBEV flexibly processing of either camera features, LiDAR features, or both. We propose a switched-modality training scheme to ensure precise predictions by using arbitrary modalities. This alternating strategy simulates real-world conditions during training, as MetaBEV randomly receives inputs from the aforementioned modalities with a predetermined probability. As a result, MetaBEV can conduct inferences on any input modality, thereby increasing its practicality in autonomous driv-", + "bbox": [ + 496, + 750, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "8725", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/22dc5fd1f853a27b986332f09aa5060174728a37a126b24075735516bc2fa7e7.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodsModalityMTLmAP(val)NDS(val)DrivablePed.CrossWalkwayStop LineCarparkDividerMean
M2BEV[36]CX41.747.077.2----40.5-
BEVFformer[21]CX41.651.780.1----25.7-
BEVFusion[25]CX35.641.281.754.858.447.450.746.456.6
X-Align[2]CX--82.455.659.349.653.847.458.0
MetaBEV-TCX49.449.783.356.761.450.855.548.059.3
MetaBEV-C55.560.4
PointPillars[16]LX52.361.372.043.153.129.727.737.543.8
CenterPoint[38]LX59.666.875.648.457.536.531.741.948.6
BEVFusion[25]LX64.769.375.648.457.536.431.741.948.6
MetaBEV-CLX62.568.687.963.471.655.055.155.764.8
MetaBEV-T64.269.3
PointPainting[31]L+CX65.869.675.948.557.136.934.541.949.1
MVP[39]L+CX66.170.076.148.757.036.933.042.249.0
TransFusion[1]L+CX67.371.2-------
BEVFusion[25]L+CX68.571.485.560.567.652.057.053.762.7
X-Align[2]L+CX--86.865.270.058.357.158.265.7
MetaBEV-TL+CX68.071.589.668.474.863.364.461.870.4
BEVFusion†[25]L+C✓-69.7------54.0
BEVFusion‡[25]L+C✓65.869.883.955.763.843.454.849.658.5
MetaBEV-MTL†L+C✓65.669.588.764.871.556.158.758.166.3
MetaBEV-MTL‡L+C✓65.469.888.564.971.856.761.158.266.9
", + "bbox": [ + 81, + 90, + 888, + 400 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 1. Comparisons with SoTA methods on nuScenes val set. We use -C and -T to denote equipping MetaBEV with the CenterPoint head [38] and Transfusion head [1]. MTL stands for testing multi-tasks with the same model. † and ‡ stand for separating or sharing the BEV feature encoder, respectively. MetaBEV outperforms the SoTA multi-modal fusion methods by +4.7% mIOU on nuScenes(val) BEV map segmentation and achieves comparable 3D object detection performance. MetaBEV also performs best in multi-task learning.", + "bbox": [ + 75, + 407, + 892, + 465 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "ing. Importantly, this approach requires only one set of pretrained weights for all the model's deployment.", + "bbox": [ + 75, + 482, + 468, + 512 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 526, + 209, + 544 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this section, we detail the implementations and experimental settings on both sensor failures and tasks conflict. The performances on 3D detection and BEV map segmentation are presented to validate the effectiveness, flexibility, and robustness of our MetaBEV.", + "bbox": [ + 75, + 551, + 468, + 628 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Implementation Details", + "text_level": 1, + "bbox": [ + 76, + 637, + 294, + 652 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Network Architectures. Swin-T [24] and VoxelNet [41] are adopted as feature encoders for the cameras and LiDAR, respectively. In the BEV-Evolving decoder, we employ four cross-modal attention layers and two self-attention layers to produce a fused BEV. We initialize the meta-BEV with a resolution of $180 \\times 180$ to capture fine-grained correlations. Subsequently, we apply an FPN layer [23] to generate multi-scale features from the fused BEV. Unless specified otherwise, we use a Transformer head for 3D detection [1, 4, 34] and a CNN head [25] for map segmentation.", + "bbox": [ + 75, + 660, + 468, + 811 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Datasets and Evaluation Metrics. We evaluate MetaBEV on nuScenes [3], a large-scale multi-modal dataset for 3D detection and map segmentation. The dataset is split into 700/150/150 scenes for training/validation/testing. It contains data from multiple sensors, including six cameras, one", + "bbox": [ + 75, + 824, + 468, + 902 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "LiDAR, and five radars. For camera inputs, each frame consists of six views of the surrounding environment at one specific timestamp. We resize the input views to $256 \\times 704$ resolution and voxelize the point cloud to $0.075\\mathrm{m}$ and $0.1\\mathrm{m}$ for detection and segmentation, respectively. Our evaluation metrics align with [3]. For 3D detection, we utilize the standard nuScenes Detection Score (NDS) and mean Average Precision (mAP). For BEV map segmentation, we follow [25] to calculate the Mean Intersection over Union (mIoU) for map segmentation on the overall six categories.", + "bbox": [ + 496, + 482, + 890, + 633 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Training configurations. We follow the image and LiDAR data augmentation strategies from MMDetection3D [9] to enlarge the training samples' diversities. AdamW [26] is utilized with a weight decay of 0.05 and a cyclical learning rate schedule [30] for optimization. We take overall 26 training epochs for 3D detection, and 20 epochs for BEV map segmentation, with CBGS [42] to balance the data sampling. MetaBEV is trained on 8 A100 GPUs. For the switched-modality training, the training ratios for camera/LiDAR/both are uniformly set to be $1/3$ , $1/3$ , and $1/3$ , respectively. Further details are available in the appendix.", + "bbox": [ + 496, + 642, + 892, + 809 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Performance on full modalities", + "text_level": 1, + "bbox": [ + 500, + 816, + 772, + 832 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "We evaluate MetaBEV on 3D object detection and BEV map segmentation, utilizing either single or full modality inputs. Note that the BEV feature map size in MetaBEV is $180 \\times 180$ , which is consistent with the BEV query utilized", + "bbox": [ + 500, + 839, + 892, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "8726", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/ea1697386a239936f8c29d172f4c4d0a81add86766d294e86f37ec96d55351b9.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodsCamera + LidarMissing CameraMissing LiDAR
mAPNDSmIoUmAPNDSmIoUmAPNDSmIoU
TransFusion [1]67.371.2-61.667.4----
BEVFusion [25]68.571.462.761.867.54.10.57.136.7
MetaBEV68.071.570.463.669.253.739.042.654.4
", + "bbox": [ + 81, + 88, + 888, + 170 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/b9f4520858cd7caf705fc533c004e2ef494a20f5c5e22b4e09204697e14b9caa.jpg", + "table_caption": [ + "Table 2. Experimental comparisons on extreme sensor missing. MetaBEV is able to totally drop the features from the missing modalities for inference, while others cannot. We attempt to replace the missing features with zero in other works so that they can output results, which are colored as blue. MetaBEV still consistently outperforms prior works when facing extreme sensor absence." + ], + "table_footnote": [], + "table_body": "
MethodsEvaluationLimited Field [-60,60]Missing Objects rate=1.0Beam Reduction 4 beamsView Drop 6 dropsView Noise 6 noiseObstacle Occlusion w occlusion
NDSmIoUNDSmIoUNDSmIoUNDSmIoUNDSmIoUNDSmIoU
BEVFusion [25]zero-shot41.647.262.161.858.355.367.54.166.925.868.645.8
MetaBEV47.061.262.569.257.764.368.343.568.045.270.061.2
BEVFusion [25]in-domain42.655.565.261.951.259.068.352.868.353.169.759.3
MetaBEV54.362.168.569.954.666.469.367.969.267.570.370.2
", + "bbox": [ + 81, + 224, + 888, + 340 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 3. Experimental comparisons on sensor corruptions. Texts in blue denote the corruption degree. More detailed results are available in the appendix. MetaBEV consistently outperforms BEVFusion on various sensor corruptions in zero-shot and in-domain tests.", + "bbox": [ + 76, + 345, + 892, + 376 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "in BEVFormer, thus being fairly compared. For 3D object detection, results in Tab. 1 show that MetaBEV achieves superior performance with the camera modality, and gets comparable performance to the state-of-the-art with both Li-DAR and multi-modalities. For example, with CenterPoint-3D [38], MetaBEV-C achieves an impressive $60.4\\%$ NDS on nuScenes val set with camera inputs, for LiDAR and multi-modal inputs, MetaBEV gains $69.3\\%$ and $71.5\\%$ , respectively, which is comparable to several SoTA methods. We also notice that though MetaBEV exhibits a slightly lower mAP with full-modality inputs, it still achieves superior NDS with improved orientation estimation ( $27.2\\%$ vs. $30.4\\%$ mAOE) as well as distance evaluation ( $28.0\\%$ vs. $28.7\\%$ mATE) in such the case. Moreover, it is experimentally found that MetaBEV is effective in capturing fine-grained features for dense predictions, e.g., semantic prediction. For single-modality inputs, with only several MLP heads for prediction, MetaBEV achieves a $59.3\\%$ mIoU on cameras, and an impressive $64.8\\%$ mIoU on LiDAR $(+16.2\\%)$ higher than BEVFusion [25]). Moreover, results in Tab. 1 show we set a new state-of-the-art (SOTA) performance of $70.4\\%$ mIoU on BEV map segmentation, outperforming the previous best model [2] with $+4.7\\%$ mIoU and the second-best method [25] by $+7.7\\%$ mIoU.", + "bbox": [ + 75, + 398, + 472, + 763 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Performance on corruption", + "text_level": 1, + "bbox": [ + 76, + 771, + 323, + 787 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We proceed to evaluate MetaBEV under various sensor failure cases, including complete sensor missing and various sensor corruptions. For the sensor missing, we train MetaBEV with the switched modality scheme, as described in Sec. 3.4. Previous fusion-based approaches, such as BEVFusion [25] and TransFusion [1], heavily rely on multi-modal features and cannot explicitly handle the ab", + "bbox": [ + 75, + 794, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "sence of features caused by sensor missing. Nevertheless, we attempt to replace missing modalities with zero-initialized features for them, allowing the prior methods for predictions. Results in Tab. 2 show that MetaBEV demonstrates a stronger anti-corruption ability. Specifically, in case of missing LiDAR, MetaBEV improves $+35.5\\%$ detection NDS and $+17.7\\%$ segmentation mAP upon BEVFusion [25]; when encountering missing cameras, MetaBEV surpasses BEVFusion [25] by $+1.7\\%$ NDS and $49.5\\%$ mIoU. Notably, even when the cameras are missing, MetaBEV still achieves $53.7\\%$ mIoU, surpassing the SoTA LiDAR-Only methods by $5.1\\%$ (i.e., CenterPoint [38]) and $9.9\\%$ (i.e., PointPillars [16]); and when the LiDAR is missing, MetaBEV even outperforms the camera-specific BEVFusion by $+1.4\\%$ NDS $(42.6\\%$ v.s. $41.2\\%)$ .", + "bbox": [ + 496, + 398, + 893, + 627 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "On the other hand, we conducted both zero-shot and in-domain tests on sensor corruptions. To evaluate the model's abilities in performing with unseen corrupted or missing data, we performed the zero-shot test by directly evaluating a trained model on such data. For the in-domain test, we train MetaBEV on corrupted data with random degrees, and then conduct evaluations on noise data with one specific degree. Tab.3 shows MetaBEV outperforms BEVFusion [25] on 11/12 corruptions on zero-shot evaluation. Moreover, when trained with randomly corrupted data, MetaBEV consistently outperformed BEVFusion. The results indicate that the fusion module, which is composed of CNNs (e.g., BEVFusion), has limited representational capabilities for corrupted data, while our approach leverages the attention mechanism for efficient modeling.", + "bbox": [ + 496, + 672, + 895, + 901 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "8727", + "bbox": [ + 480, + 944, + 514, + 957 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/4a8cfaaa028b2a552364803a5a4de143deb3f872e7121a7afd7e70db57250ac6.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
mAPNDSmIoU
Detection only67.671.0-
Segmentation only--70.4
H-MoER-MoE
XX64.869.464.7
✓X65.6 (+0.8)69.5 (+0.1)66.3 (+1.6)
X✓65.4 (+0.6)69.8 (+0.4)66.9 (+2.2)
", + "bbox": [ + 81, + 89, + 467, + 200 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/6de81b49d851561bb8c492430d354a035dd9590c80a638076524df11a0e47b1c.jpg", + "table_caption": [ + "Table 4. We experiment on two kinds of MoE structures for Multi-Task Learning, and both show significant advantages." + ], + "table_footnote": [], + "table_body": "
Method#Params.(M)mAPNDS#Params.(M)mIoU
BEVFusion40.868.571.443.162.7
BEVFusion (Heavy)54.167.270.156.165.9
MetaBEV53.568.071.555.970.4
", + "bbox": [ + 80, + 251, + 467, + 305 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 5. Comparisons on 3D detection and BEV-Map segmentation.", + "bbox": [ + 76, + 315, + 470, + 344 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.4. Performance in Multi-Task Learning", + "text_level": 1, + "bbox": [ + 76, + 364, + 397, + 382 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Tab. 4 presents the results of our multi-task learning (MTL) experiments for 3D object detection and BEV map segmentation. We begin with the framework designed for independent single-task learning with distinct task-specific heads and loaded a set of weights trained on multi-modal detection as pretrain. The model achieves $69.4\\%$ NDS and $64.7\\%$ mIoU for detection and segmentation, respectively, which is already a state-of-the-art performance. In light of this, we implement an MoE structure to help alleviate the gradient-conflict problem in MTL. Intuitively, we introduce a routing-based MoE structure, referred to as $\\mathrm{RM}^2\\mathrm{oE}$ , to replace the vanilla MLP layer. This implementation results in a remarkable improvement of $0.4\\%$ NDS in detection and $2.2\\%$ mIoU in segmentation. Considering the additional computation required by the routing mechanisms, we propose to further experiment on a simplified version $\\mathrm{HM}^2\\mathrm{oE}$ where the number of experts is adjusted to match that of the tasks, and the routing function is removed. We find it still achieves a notable improvement of $0.1\\%$ NDS and $1.6\\%$ mIoU. Upon the evaluation results, both implementations mitigate performance degradation in MTL to some extent.", + "bbox": [ + 75, + 388, + 472, + 705 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.5. Ablation Studies", + "text_level": 1, + "bbox": [ + 76, + 714, + 241, + 729 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Setup. We present the ablation studies for analyzing the network architectures and training schemes. All the ablation studies are performed on nuScenes validation set, with the training configurations set as default in Sec. 4.1.", + "bbox": [ + 75, + 737, + 468, + 799 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Network Configurations. We first explore the optimal architectures of the BEV-Evolving Decoder. Specifically, we analyze three components, including the combination of the layers, reference points number ( $p$ in Eq.1), and expert number ( $E$ in Eq.2). Our findings in Tab. 6a indicate that a few layers of cross-attention are sufficient to produce effec", + "bbox": [ + 75, + 809, + 470, + 902 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "tive predictions while stacking more cross-attention layers does not necessarily enhance the model's capacities (68.3% and 68.2% NDS for 6 and 8 cross-attention layers, respectively). The same findings also suit the reference points number, where increasing the sampling points does not necessarily lead to better performance, as shown in Tab. 6b. On the contrary, we discovered that simply adding two layers of self-attention after the cross-attention layers significantly improve the prediction performance by +1.1% NDS in Tab. 6a. As mentioned in Sec. 3.2, the hybrid designs capture both intra- and inter-correlations simultaneously, resulting in complementary modeling. Moreover, in Tab. 6c, we discover that a larger model capacity (i.e., incorporating more experts) can effectively alleviate the performance drop in 3D detection and map segmentation. Specifically, MetaBEV equipped with 2/8 expert (i.e. activating the 2 experts with the highest scores from a total of 8 experts.) achieves the best performance compared to other configurations (66.9% mIoU and 69.8% NDS), while $\\mathrm{HM}^2\\mathrm{oE}$ is unaffected due to the fixed number of experts being equivalent to the number of tasks.", + "bbox": [ + 496, + 90, + 890, + 407 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Do More Parameters Guarantee Improved Model Accuracy? We note that incorporating deformable attention does introduce additional parameters to MetaBEV; however, this increment is minimal and acceptable (i.e., 54M v.s. 41M) in relation to its functional capabilities (addressing sensor failures). Besides, compared with BEVFusion, though MetaBEV achieves modest advancements on 3D detection (+0.1% NDS), the improvement on map segmentation is remarkably significant (+7.7% mIoU), which indicates the deformable attention facilitates more in per-pixel perception. To conduct a fair comparison, we consistently introduce more fusion layers to BEVFusion. Results in Tab. 5 demonstrate that increasing parameters of BEVFusion yields an improved performance in map segmentation, while a reduction in 3D detection accuracy. The decreased performance for 3D detection may be attributed to the challenging convergence for the larger parameters. Furthermore, it is observed that BEVFusion performs poorly in both 3D detection and map segmentation when compared to MetaBEV with the same parameter amount. This finding highlights the fact that having more model parameters does not guarantee improved model accuracy.", + "bbox": [ + 496, + 420, + 890, + 752 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Switched Modality Training. For the training strategy, using switched modality scheme to simulate the sensors missing, though simple, is the key to enabling MetaBEV with robust performance on completely sensor-failure scenarios. In Tab. 6d, comparing with the vanilla full-modality training approach, our proposed training strategy yields significant improvements on 3D detection by $+32.8\\%$ NDS and $+1.0\\%$ NDS, and improvements on map segmentation by $+17.9\\%$ mIoU and $+16.7\\%$ mIoU under LiDAR-missing", + "bbox": [ + 496, + 763, + 890, + 902 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "8728", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/4a0524f56e002ad6716394d2d0784b9cd454f4832f7e31e8ef70c1bfb66040c7.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
LayersmAP/NDS
4 cross61.7/67.0
6 cross63.0/68.3
8 cross62.5/68.2
2 self+4 cross64.2/69.3
", + "bbox": [ + 135, + 88, + 343, + 181 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "(a) The number of self/Cross-layer", + "bbox": [ + 135, + 186, + 341, + 199 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/e20a4396cceaa04b809f10f68245170dfef9891aafe7ab1a5f7959b9cc8dc789.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
PointsmAP/NDS
462.3/67.9
862.7/68.2
1262.3/68.0
1662.3/68.1
", + "bbox": [ + 387, + 88, + 542, + 180 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "(b) The number of reference points", + "bbox": [ + 362, + 186, + 566, + 200 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/d2824f56813cebf984135fe0e9743669844be46f86c6721127d4e17791596852.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
ExpertsmAP/NDSmIoU
1/2 Expert65.8/69.863.3
1/4 Expert64.9/69.565.9
1/8 Expert65.4/69.766.4
2/8 Expert65.4/69.866.9
", + "bbox": [ + 589, + 88, + 834, + 180 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/66a1ac3a0c60f4f0a67c665af56a9395f75980d8725781ab0ac998bcf7bbf5cd.jpg", + "table_caption": [ + "(c) Expert number" + ], + "table_footnote": [ + "(d) Evaluation of the NuScenes val dataset when Cameras or LiDAR totally fail. We test the performance with the switched modality training on both 3D detection and BEV-map segmentation tasks.", + "Table 6. Ablation studies for the model architectures and training strategy. Default settings are marked in gray in (a), (b), and (c)." + ], + "table_body": "
TaskMetricsVanilla trainingSwitched Modality Training
Lidar-MissingCamera-MissingFullLidar-MissingCamera-MissingFull
3D detectionNDS9.868.271.042.6 (+32.8)69.2 (+1.0)71.5 (+0.5)
mAP2.962.467.439.0 (+36.1)63.6 (+1.2)68.0 (+0.6)
BEV-Map SegmentationmIoU36.527.070.454.4 (+17.9)53.7 (+16.7)68.5 (-1.9)
", + "bbox": [ + 81, + 200, + 888, + 292 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "and camera-missing scenarios, respectively. More intriguingly, we find that the switched modality training could even enhance the model performance on full modalities, rising from $71.0\\%$ NDS to $71.5\\%$ NDS on 3D detection.", + "bbox": [ + 75, + 371, + 468, + 433 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 446, + 194, + 462 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this paper, we present a novel framework, named MetaBEV, for the purpose of solving sensor failures in the bird's-eye view (BEV) 3D detection and map segmentation. Our method integrates modal-specific layers into the cross-modal attention layer to enhance the fusion process, achieving appealing performance on full-modality inputs, and meanwhile MetaBEV effectively alleviates the significant performance degradation that is often caused by corrupted or missing sensor signals. We also introduce $\\mathbf{M}^2\\mathrm{oE}$ to handle potential conflicts between tasks. We hope that MetaBEV will provide a more focused and effective approach for investigating sensor-failure scenarios in the autonomous driving field.", + "bbox": [ + 75, + 473, + 472, + 670 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Limitations. Though we adopted the deformable attention [43] for efficiency, it unavoidably leads to a slight increase in network parameters compared to the lightweight solutions [25, 22]. Despite this, the benefits of mitigating sensor failures are highly desirable, and the additional computational overhead may be deemed acceptable. We acknowledge that lightweight networks could be an avenue for future research, potentially involving techniques such as network pruning, token reduction, etc.", + "bbox": [ + 75, + 684, + 468, + 821 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement. This paper is partially supported by the National Key R&D Program of China No.2022ZD0161000 and the General Research Fund of Hong Kong No.17200622.", + "bbox": [ + 75, + 839, + 470, + 902 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 501, + 369, + 596, + 386 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Xuyang Bai, Zeyu Hu, Xinge Zhu, Qingqiu Huang, Yilun Chen, Hongbo Fu, and Chiew-Lan Tai. Transfusion: Robust lidar-camera fusion for 3d object detection with transformers. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022.", + "[2] Shubhankar Borse, Marvin Klingner, Varun Ravi Kumar, Hong Cai, Abdulaziz Almuzairee, Senthil Yogamani, and Fatih Porikli. X-align: Cross-modal cross-view alignment for bird's-eye-view segmentation. In IEEE/CVF Winter Conference on Applications of Computer Vision, 2023.", + "[3] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020.", + "[4] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In European Conference on Computer Vision, 2020.", + "[5] Runjian Chen, Yao Mu, Runsen Xu, Wenqi Shao, Chenhan Jiang, Hang Xu, Zhenguo Li, and Ping Luo. Co^3: Cooperative unsupervised 3d representation learning for autonomous driving. arXiv preprint arXiv:2206.04028, 2022.", + "[6] Xiaozhi Chen, Huimin Ma, Ji Wan, Bo Li, and Tian Xia. Multi-view 3d object detection network for autonomous driving. In Proceedings of the IEEE conference on Computer Vision and Pattern Recognition, 2017.", + "[7] Xuanyao Chen, Tianyuan Zhang, Yue Wang, Yilun Wang, and Hang Zhao. Futr3d: A unified sensor fusion framework for 3d detection. arXiv preprint arXiv:2203.10642, 2022.", + "[8] Aakanksha Chowdhery, Sharan Narang, Jacob Devlin, Maarten Bosma, Gaurav Mishra, Adam Roberts, Paul Barham, Hyung Won Chung, Charles Sutton, Sebastian Gehrmann, et al. Palm: Scaling language modeling with pathways. arXiv preprint arXiv:2204.02311, 2022." + ], + "bbox": [ + 508, + 396, + 893, + 901 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "8729", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[9] MMDetection3D Contributors. MMDetection3D: OpenMMLab next-generation platform for general 3D object detection. https://github.com/open-mmlab/mmdetection3d, 2020.", + "[10] Danny Driess, Fei Xia, Mehdi SM Sajjadi, Corey Lynch, Aakanksha Chowdhery, Brian Ichter, Ayzaan Wahid, Jonathan Tompson, Quan Vuong, Tianhe Yu, et al. Palme: An embodied multimodal language model. arXiv preprint arXiv:2303.03378, 2023.", + "[11] Chongjian Ge, Youwei Liang, Yibing Song, Jianbo Jiao, Jue Wang, and Ping Luo. Revitalizing cnn attention via transformers in self-supervised visual representation learning. Advances in Neural Information Processing Systems, 2021.", + "[12] Chongjian Ge, Jiangliu Wang, Zhan Tong, Shoufa Chen, Yibing Song, and Ping Luo. Soft neighbors are positive supporters in contrastive visual representation learning. arXiv preprint arXiv:2303.17142, 2023.", + "[13] Yihan Hu, Jiazhi Yang, Li Chen, Keyu Li, Chonghao Sima, Xizhou Zhu, Siqi Chai, Senyao Du, Tianwei Lin, Henhai Wang, et al. Planning-oriented autonomous driving. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2023.", + "[14] Tengteng Huang, Zhe Liu, Xiwu Chen, and Xiang Bai. Epnet: Enhancing point features with image semantics for 3d object detection. In European Conference on Computer Vision, 2020.", + "[15] Sebastian Jasczur, Aakanksha Chowdhery, Afroz Mohiuddin, Lukasz Kaiser, Wojciech Gajewski, Henryk Michalewski, and Jonni Kanerva. Sparse is enough in scaling transformers. Advances in Neural Information Processing Systems, 2021.", + "[16] Alex H Lang, Sourabh Vora, Holger Caesar, Lubing Zhou, Jiong Yang, and Oscar Beijbom. Pointpillars: Fast encoders for object detection from point clouds. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019.", + "[17] Dmitry Lepikhin, HyoukJoong Lee, Yuanzhong Xu, Dehao Chen, Orhan First, Yanping Huang, Maxim Krikun, Noam Shazeer, and Zhifeng Chen. Gshard: Scaling giant models with conditional computation and automatic sharding. International Conference on Learning Representations, 2020.", + "[18] Yanwei Li, Yilun Chen, Xiaojuan Qi, Zeming Li, Jian Sun, and Jiaya Jia. Unifying voxel-based representation with transformer for 3d object detection. arXiv preprint arXiv:2206.00630, 2022.", + "[19] Yingwei Li, Adams Wei Yu, Tianjian Meng, Ben Caine, Jiquan Ngiam, Daiyi Peng, Junyang Shen, Yifeng Lu, Denny Zhou, Quoc V Le, et al. Deepfusion: Lidar-camera deep fusion for multi-modal 3d object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022.", + "[20] Yingwei Li, Adams Wei Yu, Tianjian Meng, Ben Caine, Ji-quan Ngiam, Daiyi Peng, Junyang Shen, Yifeng Lu, Denny Zhou, Quoc V Le, et al. Deepfusion: Lidar-camera deep fusion for multi-modal 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022.", + "[21] Zhiqi Li, Wenhai Wang, Hongyang Li, Enze Xie, Chonghao Sima, Tong Lu, Yu Qiao, and Jifeng Dai. Bevformer:" + ], + "bbox": [ + 78, + 90, + 467, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Learning bird's-eye-view representation from multi-camera images via spatiotemporal transformers. In European Conference on Computer Vision, 2022.", + "[22] Tingting Liang, Hongwei Xie, Kaicheng Yu, Zhongyu Xia, Zhiwei Lin, Yongtao Wang, Tao Tang, Bing Wang, and Zhi Tang. Bevfusion: A simple and robust lidar-camera fusion framework. arXiv preprint arXiv:2205.13790, 2022.", + "[23] Tsung-Yi Lin, Piotr Dólar, Ross Girshick, Kaiming He, Bharath Hariharan, and Serge Belongie. Feature pyramid networks for object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2017.", + "[24] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In IEEE/CVF International Conference on Computer Vision, 2021.", + "[25] Zhijian Liu, Haotian Tang, Alexander Amini, Xinyu Yang, Huizi Mao, Daniela Rus, and Song Han. Bevfusion: Multi-task multi-sensor fusion with unified bird's-eye view representation. arXiv preprint arXiv:2205.13542, 2022.", + "[26] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. arXiv preprint arXiv:1711.05101, 2017.", + "[27] Jonah Philion and Sanja Fidler. Lift, splat, shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3d. In European Conference on Computer Vision, 2020.", + "[28] Noam Shazeer, Azalia Mirhoseini, Krzysztof Maziarz, Andy Davis, Quoc Le, Geoffrey Hinton, and Jeff Dean. Outrageously large neural networks: The sparsely-gated mixture-of-experts layer. arXiv preprint arXiv:1701.06538, 2017.", + "[29] Vishwanath A Sindagi, Yin Zhou, and Oncel Tuzel. Mvxnet: Multimodal voxelnet for 3d object detection. In International Conference on Robotics and Automation, 2019.", + "[30] Leslie N Smith. Cyclical learning rates for training neural networks. In IEEE/CVF Winter Conference on Applications of Computer Vision, 2017.", + "[31] Sourabh Vora, Alex H Lang, Bassam Helou, and Oscar Beijbom. Pointpainting: Sequential fusion for 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020.", + "[32] Chunwei Wang, Chao Ma, Ming Zhu, and Xiaokang Yang. Pointaugmenting: Cross-modal augmentation for 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021.", + "[33] Xin Wang, Fisher Yu, Lisa Dunlap, Yi-An Ma, Ruth Wang, Azalia Mirhoseini, Trevor Darrell, and Joseph E Gonzalez. Deep mixture of experts via shallow embedding. In Uncertainty in artificial intelligence, pages 552-562, 2020.", + "[34] Yue Wang, Vitor Campagnolo Guizilini, Tianyuan Zhang, Yilun Wang, Hang Zhao, and Justin Solomon. Detr3d: 3d object detection from multi-view images via 3d-to-2d queries. In Conference on Robot Learning, 2022.", + "[35] Barret Zoph William Fedus and Noam Shazeer. Switch transformers: Scaling to trillion parameter models with simple and efficient sparsity. Computer Research Repository, 2021.", + "[36] Enze Xie, Zhiding Yu, Daquan Zhou, Jonah Philion, Anima Anandkumar, Sanja Fidler, Ping Luo, and Jose M Alvarez. M^2bev: Multi-camera joint 3d detection and segmentation" + ], + "bbox": [ + 503, + 92, + 890, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "8730", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "with unified birds-eye view representation. arXiv preprint arXiv:2204.05088, 2022.", + "[37] Brandon Yang, Gabriel Bender, Quoc V Le, and Jiquan Ngiam. Condconv: Conditionally parameterized convolutions for efficient inference. Advances in Neural Information Processing Systems, 2019.", + "[38] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Center-based 3d object detection and tracking. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021.", + "[39] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Multimodal virtual point 3d detection. Advances in Neural Information Processing Systems, 2021.", + "[40] Kaicheng Yu, Tang Tao, Hongwei Xie, Zhiwei Lin, Zhongwei Wu, Zhongyu Xia, Tingting Liang, Haiyang Sun, Jiong Deng, Dayang Hao, et al. Benchmarking the robustness of lidar-camera fusion for 3d object detection. arXiv preprint arXiv:2205.14951, 2022.", + "[41] Yin Zhou and Oncel Tuzel. Voxelnet: End-to-end learning for point cloud based 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2018.", + "[42] Benjin Zhu, Zhengkai Jiang, Xiangxin Zhou, Zeming Li, and Gang Yu. Class-balanced grouping and sampling for point cloud 3d object detection. arXiv preprint arXiv:1908.09492, 2019.", + "[43] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable detr: Deformable transformers for end-to-end object detection. arXiv preprint arXiv:2010.04159, 2020." + ], + "bbox": [ + 78, + 90, + 468, + 487 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "8731", + "bbox": [ + 482, + 945, + 513, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/5204095b-1c9c-4150-9f9c-b1c27fdd82da_model.json b/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/5204095b-1c9c-4150-9f9c-b1c27fdd82da_model.json new file mode 100644 index 0000000000000000000000000000000000000000..8da72e4c28502e6b268e372863dbb51c9da3c718 --- /dev/null +++ b/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/5204095b-1c9c-4150-9f9c-b1c27fdd82da_model.json @@ -0,0 +1,1971 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.044 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.104, + 0.131, + 0.867, + 0.155 + ], + "angle": 0, + "content": "MetaBEV: Solving Sensor Failures for 3D Detection and Map Segmentation" + }, + { + "type": "text", + "bbox": [ + 0.224, + 0.179, + 0.741, + 0.199 + ], + "angle": 0, + "content": "Chongjian Ge\\(^{1*}\\) Junsong Chen\\(^{3,1*}\\) Enze Xie\\(^{2\\dagger}\\) Zhongdao Wang\\(^{2}\\)" + }, + { + "type": "text", + "bbox": [ + 0.256, + 0.199, + 0.714, + 0.218 + ], + "angle": 0, + "content": "Lanqing Hong² Huchuan Lu³ Zhenguo Li² Ping Luo¹,⁴†" + }, + { + "type": "text", + "bbox": [ + 0.251, + 0.22, + 0.721, + 0.238 + ], + "angle": 0, + "content": "1The University of Hong Kong 2Huawei Noah's Ark Lab" + }, + { + "type": "text", + "bbox": [ + 0.25, + 0.238, + 0.721, + 0.256 + ], + "angle": 0, + "content": "\\(^{3}\\)Dalian University of Technology \\(^{4}\\)Shanghai AI Laboratory" + }, + { + "type": "text", + "bbox": [ + 0.174, + 0.259, + 0.796, + 0.273 + ], + "angle": 0, + "content": "rhettgee \\(@\\) connect.hku.hk jschen@mail.dlut.edu.cn lhchuan@dlut.edu.cn" + }, + { + "type": "text", + "bbox": [ + 0.162, + 0.276, + 0.81, + 0.291 + ], + "angle": 0, + "content": "{xie.enze, wangzhongdao, honglanqing, li.zhenguo}@huawei.com pluo@cs.hku.hk" + }, + { + "type": "text", + "bbox": [ + 0.256, + 0.294, + 0.714, + 0.309 + ], + "angle": 0, + "content": "Project page: https://chongjiange.github.io/metabev.html" + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.317, + 0.891, + 0.525 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.543, + 0.893, + 0.599 + ], + "angle": 0, + "content": "Figure 1. Selected 3D prediction results under various sensor failures. MetaBEV shows stronger robustness on both map segmentation and 3D detection compared to the representative multi-modal method, e.g., BEVFusion [25]. Notably, in case of an entire sensor absent (e.g., Camera or LiDAR), MetaBEV provides satisfactory outcomes while existing methods fail to. Top two rows: 3D prediction results. Bottom row: the corresponding ground truths." + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.612, + 0.314, + 0.628 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.646, + 0.471, + 0.858 + ], + "angle": 0, + "content": "Perception systems in modern autonomous driving vehicles typically take inputs from complementary multi-modal sensors, e.g., LiDAR and cameras. However, in real-world applications, sensor corruptions and failures lead to inferior performances, thus compromising autonomous safety. In this paper, we propose a robust framework, called MetaBEV, to address extreme real-world environments, involving overall six sensor corruptions and two extreme sensor-missing situations. In MetaBEV, signals from multiple sensors are first processed by modal-specific encoders. Subsequently, a set of dense BEV queries are initialized, termed meta-BEV. These queries are then processed iteratively by a BEV-Evolving decoder, which selectively aggregates deep features from either LiDAR, cameras, or both" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.613, + 0.893, + 0.871 + ], + "angle": 0, + "content": "modalities. The updated BEV representations are further leveraged for multiple 3D prediction tasks. Additionally, we introduce a new \\( M^2 oE \\) structure to alleviate the performance drop on distinct tasks in multi-task joint learning. Finally, MetaBEV is evaluated on the nuScenes dataset with 3D object detection and BEV map segmentation tasks. Experiments show MetaBEV outperforms prior arts by a large margin on both full and corrupted modalities. For instance, when the LiDAR signal is missing, MetaBEV improves \\( 35.5\\% \\) detection NDS and \\( 17.7\\% \\) segmentation mIoU upon the vanilla BEVFusion [25] model; and when the camera signal is absent, MetaBEV still achieves \\( 69.2\\% \\) NDS and \\( 53.7\\% \\) mIoU, which is even higher than previous works that perform on full-modalities. Moreover, MetaBEV performs moderately against previous methods in both canonical perception and multi-task learning settings, refreshing state-of-the-art nuScenes BEV map segmentation with \\( 70.4\\% \\) mIoU." + }, + { + "type": "page_footnote", + "bbox": [ + 0.094, + 0.875, + 0.217, + 0.888 + ], + "angle": 0, + "content": "\\(^{0}*\\) Equal contribution." + }, + { + "type": "page_footnote", + "bbox": [ + 0.097, + 0.888, + 0.237, + 0.9 + ], + "angle": 0, + "content": "\\(^{0}\\dagger\\) Corresponding authors." + }, + { + "type": "list", + "bbox": [ + 0.094, + 0.875, + 0.237, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "8721" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.09, + 0.21, + 0.107 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.116, + 0.47, + 0.326 + ], + "angle": 0, + "content": "Perceiving the surrounding environment is a fundamental capability of autonomous driving systems. In pursuit of higher perceptual accuracy, prior works make significant efforts in designing stronger task-specific modules [41, 16, 21], cultivating effective training paradigms [5], leveraging multi-modalities [25, 22, 7], etc. Among all these, the multi-sensors fusion strategy exhibits significant advantages in achieving stronger perception abilities [31, 39, 25, 1], thus being widely explored in both academia and industry. While the majority of works focus on achieving optimal performance on ideal multi-modal inputs for a single specific task, they unintentionally neglect how the designed models perform with sensor failures, which are commonly encountered and inevitable in real-world applications." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.327, + 0.471, + 0.644 + ], + "angle": 0, + "content": "To alleviate performance drop on sensor failures, previous works encounter two challenges as follows. 1) Features misalignment: Existing fusion methods typically utilize CNNs and features concatenation for fusion [25, 22]. The pixel-level position correlation is consistently imposed, giving rise to multi-modal features misalignment, especially when geometric-related noises are introduced. This issue could be attributed to the intrinsic characteristics of CNNs, which exhibit limitations in long-range perception and adaptive attention to input features. 2) Heavily reliant on complete modalities: Prior arts generate the fused BEV features using either query-indexing or channel-wise fusion manners. Query-indexing methods [29, 31, 32, 14] typically rely on LiDAR and 2D Camera features for mutual querying, while channel-wise fusion approaches [25, 22] are inevitable to involve element-wise operations (e.g. element-sum) for feature merging. Both fusion strategies are heavily dependent on complete modality inputs and lead to inferior perception performance encountering extreme sensor failures such as LiDAR-missing or Cameras-missing, thus being limited in the practical applications." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.645, + 0.47, + 0.84 + ], + "angle": 0, + "content": "In this research, we propose MetaBEV to tackle the above features misalignment and full-modality dependence problems through modality-arbitrary and task-agnostic learning in the unified bird's-eye view (BEV) representation space [18]. We identify the major bottleneck in modality-dependent methods is the lack of designs that enable independent fusion of different modalities by the fusion module. Therefore, we present a modality-arbitrary BEV-Evolving decoder, which leverages cross-modal attention to correlate the learnable meta-BEV queries with either a single camera-BEV feature, LiDAR-BEV feature, or both to eliminate the bottleneck. Finally, we apply a few task-specific heads to support different 3D perception predictions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Except for the canonical perception (on no corrupted sensors), we also evaluate MetaBEV on overall six sensor corruptions (Limited Field (LF), Beams Reduction (BR), Missing Objects (MO), View Drop (VD), View Noise (VN)," + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.093, + 0.887, + 0.224 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.23, + 0.895, + 0.367 + ], + "angle": 0, + "content": "Figure 2. MetaBEV shows stronger robustness on missing sensors. We perform representative methods with full/missing modalities on both map segmentation (the left part) and 3D detection (the right part). Results show MetaBEV can mitigate the performance drop on input absence. Quantitatively, when facing missing cameras, MetaBEV still achieves \\(53.7\\%\\) mIoU, which outperforms the representative method (i.e., BEVFusion [25]), by \\(+49.6\\%\\) mIoU, and is even better than MVP [39] performed on full-modalities. The superior performance could also be found on 3D detection tasks." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.405, + 0.892, + 0.617 + ], + "angle": 0, + "content": "Obstacle Occlusion (OO)) and two sensor-missing scenarios (Missing LiDAR (ML) and Missing Camera (MC)). Compared with prior works, MetaBEV performs more robustly as depicted in Fig. 1. For example, it achieves \\(69.2\\%\\) NDS and \\(42.6\\%\\) NDS on detection when totally missing the cameras or LiDAR, respectively. For map segmentation, when total cameras absence occurs, MetaBEV could still achieve better performance compared to the work trained on multi-modalities (i.e., \\(54.7\\%\\) v.s. MVP's \\(49.0\\%\\) mIoU [39]). Besides, the attention-based MetaBEV exhibits inherent robustness against multiple heavy corruptions with zero-shot and in-domain tests. For instance, as shown in Tab. 3, even missing \\(66.6\\%\\) of LiDAR points, MetaBEV still achieves \\(55\\%\\) NDS, outperforming the competitor by \\(+11.7\\%\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.617, + 0.892, + 0.782 + ], + "angle": 0, + "content": "Moreover, considering the limited computational resource in practice, using a single framework with shared parameters for different tasks is more efficient than using separate frameworks for multiple tasks. However, the task conflicts in the joint learning of detection and segmentation often lead to severe performance drop [36, 21, 25], and existing methods rarely analyze and design for multi-task learning (MTL). We incorporate MetaBEV with a flexible module based on Multi-Task Mixture of Experts \\((\\mathbf{M}^2\\mathrm{oE})\\) to demonstrate one possible solution for MTL and hope to stimulate further research in this area." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.784, + 0.882, + 0.799 + ], + "angle": 0, + "content": "The appealing advantages of MetaBEV are concluded:" + }, + { + "type": "text", + "bbox": [ + 0.514, + 0.81, + 0.892, + 0.901 + ], + "angle": 0, + "content": "1. MetaBEV is a novel BEV perception framework for 3D object detection and BEV map segmentation, which can maintain resilient performance under arbitrary sensor input. Plenty of real-world sensor corruptions are formulated as well as methodically experimented with and analyzed to verify its robustness." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8722" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.089, + 0.09, + 0.468, + 0.136 + ], + "angle": 0, + "content": "2. MetaBEV involves the \\(\\mathbf{M}^2\\mathrm{oE}\\) structures to alleviate tasks conflict when performing 3D detection and segmentation tasks with the same trained weights." + }, + { + "type": "text", + "bbox": [ + 0.089, + 0.149, + 0.468, + 0.208 + ], + "angle": 0, + "content": "3. MetaBEV achieves state-of-the-art performance on nuScenes dataset [3]. It's the first method designed for both sensor failures and tasks conflict. We hope MetaBEV will facilitate future research." + }, + { + "type": "list", + "bbox": [ + 0.089, + 0.09, + 0.468, + 0.208 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.224, + 0.218, + 0.239 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.249, + 0.293, + 0.264 + ], + "angle": 0, + "content": "2.1. LiDAR-Camera Fusion" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.273, + 0.468, + 0.514 + ], + "angle": 0, + "content": "In 3D perception tasks, the effectiveness of multi-sensor fusion is notable. Therefore, researchers have focused on better combining geometric-centric point clouds and semantic-centric images. Existing methods mainly focus on three aspects: proposal-level [6], point-level [7, 1, 19], and feature-level [25, 22]. While attempting to combine multiple modalities, existing approaches typically adopt similar fusion strategies, including query-indexing fusion [1] and channel-wise fusion [25, 22]. Though showing effective in full-modality input, the above fusion manners usually associate multi-modal features tightly among points or pixels, causing features in these methods to be susceptible to spatial misalignment issues and suffering from system collapses due to sensor missing. In our work, we explore an approach that can handle arbitrary modality freely to mitigate the above limitations." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.526, + 0.32, + 0.541 + ], + "angle": 0, + "content": "2.2. Sensors-Failure Perception" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.55, + 0.468, + 0.776 + ], + "angle": 0, + "content": "Sensor failures can significantly impact the accuracy of 3D perception, thereby jeopardizing the safety of autonomous driving. Therefore, conducting research on sensor failures is of utmost practical importance. Prior arts have made preliminary attempts to propose robust frameworks that address specific sensor failure scenarios on a case-by-case basis. These scenarios include camera-views drop [1], changes in illumination conditions [25, 7, 1], noisy inputs [20], and etc. More recently, [40] provided a comprehensive benchmark for verifying the robustness of methods mainly on sensor degradation. While previous works mainly focus on sensor corruptions, sensor absence is rarely noticed. In this work, we propose a novel perception framework that analyzes not only the aspects of sensor corruptions but also sensor absence comprehensively." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.787, + 0.274, + 0.803 + ], + "angle": 0, + "content": "2.3. Multi-Task Learning" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.811, + 0.468, + 0.9 + ], + "angle": 0, + "content": "Multi-task learning denotes performing multiple task predictions with one set of trained weights, which appeals to the research community for its practical values, such as the complementary performance, less computational cost, etc. However, multi-task learning can also be challenging, as the model must learn to balance various objectives of" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.424 + ], + "angle": 0, + "content": "each task and avoid tasks conflict. In 3D perception, the tasks conflict has been proven by \\(\\mathbf{M}^2\\mathrm{BEV}\\) [36] and BEVFormer [21], which both perform joint training on camera-only 3D object detection and BEV map segmentation. It is empirically found that joint training leads to severe accuracy degradation on each single task. Prior arts do not address the issues effectively due to their unified models and usually solve the problems from the learning perspective. For example, UniAD [13] adopts multiple training stages to adjust the overall network module by module to avoid gradient conflicts in multi-task learning, which is not end-to-end and can not be optimized layer-by-layer to adjust gradients. Inspired by Mixture-of-Expert (MoE), which is specially designed for large language model in the Natural Language Processing [35, 17, 15, 37, 33] and self-supervised field [8, 11, 12, 10], we introduce a robust fusion module with a new \\(\\mathbf{M}^2\\mathrm{oE}\\)-FFN layer. The main purpose is to mitigate the gradient conflict between detection and segmentation to achieve a more balanced performance. MetaBEV is the first framework introducing MoE into 3D object detection and BEV map segmentation as a multi-modal, multitask, and robust approach." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.436, + 0.679, + 0.451 + ], + "angle": 0, + "content": "3. MetaBEV Method" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.462, + 0.892, + 0.628 + ], + "angle": 0, + "content": "We introduce a new baseline, which targets solving a range of sensor failures on 3D object detection and BEV map segmentation tasks. As opposed to existing perception methods that heavily rely on the complete sensor inputs, we connect different modalities through a parameterized metaBEV query and perform cross-modal attention to integrate both semantic and geometry representations from cameras and LiDAR. As shown in Figure 3, the overall pipeline consists of a multi-modalities feature encoder, a BEV-Evolving decoder with cross-modal deformable attention, and task-specific heads. Architecture designs are detailed as follows." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.637, + 0.783, + 0.651 + ], + "angle": 0, + "content": "3.1. BEV Feature Encoder Overview" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.66, + 0.891, + 0.78 + ], + "angle": 0, + "content": "MetaBEV generates fused features in the BEV space, as BEV representation provides a solution to combine image features with insufficient geometric knowledge and Li-DAR features lacking semantic understanding in a unified domain, allowing for complementary fusion. Additionally, the regularity of the BEV feature facilitates the effective integration of various advanced task heads, which could benefit plenty of perception tasks." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Camera/LiDAR to BEV. We build our multi-modal feature encoder based on the state-of-the-art perception method BEVFusion [25], which takes multi-view-images and LiDAR-points pair as input and transforms the camera features into BEV space with depth prediction and geometric projection, respectively. Specifically, we adopt a camera backbone \\(\\phi_c(\\cdot)\\) to generate \\(N\\)-view 2D image representations \\(F_{c}^{i}, i \\in [1,2,\\dots ,N]\\). Then, following LSS [27], we" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.946, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8723" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.1, + 0.09, + 0.873, + 0.25 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.254, + 0.894, + 0.311 + ], + "angle": 0, + "content": "Figure 3. An overview of MetaBEV framework. The multi-modal inputs are separately processed by the camera encoder \\(\\phi_c(\\cdot)\\) and LiDAR encoder \\(\\phi_l(\\cdot)\\) to produce the BEV representations \\(B_{c}, B_{l}\\). To generate the fused BEV features, a BEV-Evolving decoder takes multi-modal BEV representations and an externally initialized meta-BEV feature (as a query feature) for correlation computation. Task-specific heads take the fused features for 3D detection." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.335, + 0.47, + 0.456 + ], + "angle": 0, + "content": "scatter the dense feature \\( F_{c}^{i} \\) into discrete 3D space and compress the generated 3D voxel features \\( V_{c} \\in \\mathbb{R}^{D \\times C \\times X \\times Y} \\) into the camera BEV representations \\( B_{c} \\in \\mathbb{R}^{C \\times X \\times Y} \\) with the pillar format [25], where \\( D, C, (X, Y) \\) denote the depth, dimension and spatial resolution of BEV feature, respectively. As for the LiDAR points, voxelization and sparse 3D convolutions \\( \\phi_{l}(\\cdot) \\) are utilized for encoding LiDAR BEV representation \\( B_{l} \\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.457, + 0.471, + 0.621 + ], + "angle": 0, + "content": "Subsequently, Previous works [25, 22] usually involve concatenating and CNN-based feature fusion, which may cause significant performance drop under sensor corruptions or even system collapse when sensor failures occur. As mentioned in Sec. 1, CNNs exhibit limited effectiveness in large-corruption of input modality (due to the local-aggregation characteristic) and are inappropriate to deal with the absent input modality caused by sensor missing (due to the weight-sharing modeling). We solve the above challenges by introducing BEV-Evolving Decoder as follows." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.634, + 0.292, + 0.65 + ], + "angle": 0, + "content": "3.2. BEV-Evolving Decoder" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.659, + 0.47, + 0.901 + ], + "angle": 0, + "content": "The BEV-Evolving decoder consists of three key components: the cross-modal attention layers, the self-attention layers, and the plug-and-play \\(\\mathbf{M}^2\\mathrm{oE}\\) blocks. The above two components facilitate fusing arbitrary modalities, while the \\(\\mathbf{M}^2\\mathrm{oE}\\) blocks are designed for mitigating the tasks conflict. Cross-Modal Attention Layer. We first initialize a set of dense BEV queries, each representing the feature within a specific spatial grid, termed meta-BEV \\((B_{m})\\). \\(B_{m}\\) is added with position embeddings (PE) and then correlates with either a camera BEV feature \\((B_{c})\\), LiDAR BEV feature \\((B_{l})\\) or both. To improve the computational efficiency, we adopt deformable attention \\(\\mathrm{DAttn}(\\cdot)\\) [43]. However, the original implementation \\(\\mathrm{DAttn}(\\cdot)\\) is not suitable for processing arbitrary inputs, as it utilizes one unified MLP layer to sample reference points \\(\\Delta p\\) and attention weights \\(A\\). We then introduce model-specific MLP layers (i.e., C-MLP for cameras" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.335, + 0.895, + 0.472 + ], + "angle": 0, + "content": "and L-MLP for LiDAR in Fig. 4 III) for the flexibility of fusion. Given any input BEV representations \\( x \\in [B_c, B_l] \\) as value features, we first generate model-specific sampling offsets \\( \\Delta p^x \\) and attention weights \\( A^x \\) from query \\( B_m \\). We then combine the pixel coordinates of \\( B_m \\) and the corresponding offsets \\( \\Delta p^x \\) to locate the sampled value features. After re-scaling the sampled features by the attention weights \\( A^x \\), meta-BEV is updated from informative sensor features. The overall process is formulated in the following," + }, + { + "type": "equation", + "bbox": [ + 0.518, + 0.49, + 0.892, + 0.554 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathrm {D A t t n} \\left(B _ {m}, p, x\\right) = \\\\ \\sum_ {m = 1} ^ {M} W _ {m} \\left[ \\sum_ {x \\in \\left[ B _ {c} \\cup B _ {l} \\right]} \\sum_ {k = 1} ^ {K} A _ {m k} ^ {x} \\cdot W _ {m} ^ {\\prime} x \\left(p + \\Delta p _ {m k} ^ {x}\\right) \\right], \\tag {1} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.567, + 0.892, + 0.673 + ], + "angle": 0, + "content": "where \\( m \\) denotes the attention head, \\( K \\) denotes the number of sampled keys, and \\( p \\) denotes reference points. We use \\( W_{m} \\) and \\( W_{m}^{\\prime} \\) to represent the learnable projection matrixes. Note that in Eq. 1, the input feature \\( x \\) could be either \\( B_{c} \\), \\( B_{l} \\), or both. It enables MetaBEV to flexibly utilize multimodal features for the deformable attention calculation during both training and testing." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.674, + 0.892, + 0.854 + ], + "angle": 0, + "content": "The cross-attention mechanism performs the fusion process layer by layer, enabling the meta-BEV to iteratively \"evolve\" into fused features that capture both semantic and geometric information from the cameras and LiDAR modalities, respectively. Note that we sequentially incorporate \\(N\\) cross-modal attention layers to capture intercorrelations among the meta-BEV and diverse sensor features. Nonetheless, we have not yet explicitly modeled the intra-correlations, which refer to as the connection among different queries. Therefore, we introduce the self-attention layers to facilitate fused features capturing the intra-correlations. The details are discussed below." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Self-Attention Layer. To construct the self-attention layer, we downgrade the modal-specific MLP into the unified MLP layer. Besides, to sufficiently model intra-correlations" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8724" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.088, + 0.09, + 0.495, + 0.253 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.496, + 0.091, + 0.882, + 0.253 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.255, + 0.894, + 0.298 + ], + "angle": 0, + "content": "Figure 4. Detailed illustration of a BEV-Evolving block. In the cross-modal deformable attention layer, We incorporate model-specific MLP layers to enable flexibly calculating sampling offsets and attention weights for an arbitrary modality. In FFN layer, we incorporate two MoE options to alleviate tasks conflict in multi-task learning." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.335, + 0.468, + 0.499 + ], + "angle": 0, + "content": "among queries, the input feature \\( x \\) in Eq. 1 is substituted by \\( B_{m} \\), resulting in a self-attention calculation \\( \\mathrm{DA}\\mathrm{attn}(B_m,p,B_m) \\). We assemble only \\( M = 2 \\) self-attention layers in the BEV-Evolving Decoder, achieving a favorable trade-off between performance and computational efficiency. By modeling inter-modalities and intra-queries correlations, the fused BEV features are finally output for 3D predictions. It's experimentally found that the hybrid designs, combining both intra- and inter-correlations, provide comprehensive modeling on the fused BEV features, thus benefiting various tasks (as validated in Sec. 4.5)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.5, + 0.468, + 0.606 + ], + "angle": 0, + "content": "\\(\\mathbf{M}^2\\mathbf{o}\\mathbf{E}\\) Block. As shown in Fig. 4 I and II, following the previous setting of [28] that is designed for large language modeling via a mixture of experts layers (MoE), we incorporate the MLP layer in our BEV-Evolving block with MoE to introduce our \\(\\mathbf{M}^2\\mathbf{o}\\mathbf{E}\\) blocks for multi-task learning. We first illustrate the \\(\\mathrm{RM}^2\\mathrm{oE}\\) (as shown in Fig. 4 I) with the following formulation," + }, + { + "type": "equation", + "bbox": [ + 0.15, + 0.615, + 0.469, + 0.655 + ], + "angle": 0, + "content": "\\[\n\\mathrm {M} ^ {2} \\mathrm {o E} (x) = \\sum_ {i = 1} ^ {t} \\mathcal {R} (x) _ {i} \\mathcal {E} _ {i} (x), t \\ll E \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.658, + 0.469, + 0.901 + ], + "angle": 0, + "content": "where \\( x \\in \\mathbb{R}^D \\) is the input tokens to the \\( \\mathrm{RM}^2\\mathrm{oE} \\)-FFN layer, \\( \\mathcal{R} : \\mathbb{R}^D \\to \\mathbb{R}^E \\) is a routing function which assigns each token to its belonging experts and \\( \\mathcal{E}_i : \\mathbb{R}^D \\to \\mathbb{R}^D \\) is the token processing in expert \\( i \\). Both \\( \\mathcal{E}_i \\) and \\( \\mathcal{R} \\) are implemented by MLP layers, and \\( E \\) is a hyper-parameter as the total expert capacity. With sparse \\( \\mathcal{R} \\) where top \\( t \\) probability is selected, each token can only be routed to \\( t \\ll E \\) experts, while a lot of experts remain inactive. Under the extreme condition of \\( t = 1 \\), the additional calculation only comes from \\( \\mathcal{R} \\). For \\( \\mathrm{HM}^2\\mathrm{oE} \\), Fig. 4 II depicts a degenerate version when \\( E = \\text{task number} \\) and \\( \\mathcal{R} = 1 \\). In this scenario, tokens bypass the router allocation process and pass through the task-specific FFN networks before being merged by the task-fusion network. This super-linear scaling of the MLP layer facilitates multi-task training and inference by enabling the router to select appropriate experts. During network opti" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.335, + 0.892, + 0.396 + ], + "angle": 0, + "content": "mization, such a process mitigates tasks conflict between 3D object detection and BEV map segmentation by separating the conflicting gradients (caused by diverse training objectives) with different experts." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.406, + 0.655, + 0.42 + ], + "angle": 0, + "content": "3.3. Sensor Failures" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.429, + 0.892, + 0.716 + ], + "angle": 0, + "content": "A practical perception model is required to perform effectively even encountering corrupted or absent inputs. To this end, we define a series of sensor failures to simulate both sensor corruptions and complete sensor absence. For sensor corruptions, we include six types: 1) Limited Field of LiDAR (LF), which occurs when LiDAR data can only be collected from a portion of the field of view due to incorrect collection or partial hardware damage [40]; 2) Missing of Objects (MO), which appears when certain materials prevent some LiDAR points from being reflected [40]; 3) Beams Reduction (BR), occurring due to limited power supply or sensor processing capabilities; 4) View Drop (VD) and 5) View Noise (VN), resulting from camera faults; and 6) Obstacle Occlusion (OO), that is a real-world phenomenon where objects are occluded from the cameras. Furthermore, we evaluate MetaBEV using extreme sensor absence scenarios, including Missing Camera(MC) and Missing LiDAR(ML). As such, our evaluation takes into account both sensor corruptions and absence." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.727, + 0.753, + 0.743 + ], + "angle": 0, + "content": "3.4. Switched Modality Training" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.892, + 0.901 + ], + "angle": 0, + "content": "The unique designs (i.e., modal-specific modules) in the BEV-Evolving block enable MetaBEV flexibly processing of either camera features, LiDAR features, or both. We propose a switched-modality training scheme to ensure precise predictions by using arbitrary modalities. This alternating strategy simulates real-world conditions during training, as MetaBEV randomly receives inputs from the aforementioned modalities with a predetermined probability. As a result, MetaBEV can conduct inferences on any input modality, thereby increasing its practicality in autonomous driv-" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8725" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.091, + 0.89, + 0.401 + ], + "angle": 0, + "content": "
MethodsModalityMTLmAP(val)NDS(val)DrivablePed.CrossWalkwayStop LineCarparkDividerMean
M2BEV[36]CX41.747.077.2----40.5-
BEVFformer[21]CX41.651.780.1----25.7-
BEVFusion[25]CX35.641.281.754.858.447.450.746.456.6
X-Align[2]CX--82.455.659.349.653.847.458.0
MetaBEV-TCX49.449.783.356.761.450.855.548.059.3
MetaBEV-C55.560.4
PointPillars[16]LX52.361.372.043.153.129.727.737.543.8
CenterPoint[38]LX59.666.875.648.457.536.531.741.948.6
BEVFusion[25]LX64.769.375.648.457.536.431.741.948.6
MetaBEV-CLX62.568.687.963.471.655.055.155.764.8
MetaBEV-T64.269.3
PointPainting[31]L+CX65.869.675.948.557.136.934.541.949.1
MVP[39]L+CX66.170.076.148.757.036.933.042.249.0
TransFusion[1]L+CX67.371.2-------
BEVFusion[25]L+CX68.571.485.560.567.652.057.053.762.7
X-Align[2]L+CX--86.865.270.058.357.158.265.7
MetaBEV-TL+CX68.071.589.668.474.863.364.461.870.4
BEVFusion†[25]L+C✓-69.7------54.0
BEVFusion‡[25]L+C✓65.869.883.955.763.843.454.849.658.5
MetaBEV-MTL†L+C✓65.669.588.764.871.556.158.758.166.3
MetaBEV-MTL‡L+C✓65.469.888.564.971.856.761.158.266.9
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.408, + 0.893, + 0.466 + ], + "angle": 0, + "content": "Table 1. Comparisons with SoTA methods on nuScenes val set. We use -C and -T to denote equipping MetaBEV with the CenterPoint head [38] and Transfusion head [1]. MTL stands for testing multi-tasks with the same model. † and ‡ stand for separating or sharing the BEV feature encoder, respectively. MetaBEV outperforms the SoTA multi-modal fusion methods by +4.7% mIOU on nuScenes(val) BEV map segmentation and achieves comparable 3D object detection performance. MetaBEV also performs best in multi-task learning." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.483, + 0.47, + 0.513 + ], + "angle": 0, + "content": "ing. Importantly, this approach requires only one set of pretrained weights for all the model's deployment." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.527, + 0.21, + 0.545 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.553, + 0.47, + 0.629 + ], + "angle": 0, + "content": "In this section, we detail the implementations and experimental settings on both sensor failures and tasks conflict. The performances on 3D detection and BEV map segmentation are presented to validate the effectiveness, flexibility, and robustness of our MetaBEV." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.638, + 0.295, + 0.654 + ], + "angle": 0, + "content": "4.1. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.661, + 0.47, + 0.813 + ], + "angle": 0, + "content": "Network Architectures. Swin-T [24] and VoxelNet [41] are adopted as feature encoders for the cameras and LiDAR, respectively. In the BEV-Evolving decoder, we employ four cross-modal attention layers and two self-attention layers to produce a fused BEV. We initialize the meta-BEV with a resolution of \\(180 \\times 180\\) to capture fine-grained correlations. Subsequently, we apply an FPN layer [23] to generate multi-scale features from the fused BEV. Unless specified otherwise, we use a Transformer head for 3D detection [1, 4, 34] and a CNN head [25] for map segmentation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Datasets and Evaluation Metrics. We evaluate MetaBEV on nuScenes [3], a large-scale multi-modal dataset for 3D detection and map segmentation. The dataset is split into 700/150/150 scenes for training/validation/testing. It contains data from multiple sensors, including six cameras, one" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.483, + 0.892, + 0.635 + ], + "angle": 0, + "content": "LiDAR, and five radars. For camera inputs, each frame consists of six views of the surrounding environment at one specific timestamp. We resize the input views to \\(256 \\times 704\\) resolution and voxelize the point cloud to \\(0.075\\mathrm{m}\\) and \\(0.1\\mathrm{m}\\) for detection and segmentation, respectively. Our evaluation metrics align with [3]. For 3D detection, we utilize the standard nuScenes Detection Score (NDS) and mean Average Precision (mAP). For BEV map segmentation, we follow [25] to calculate the Mean Intersection over Union (mIoU) for map segmentation on the overall six categories." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.643, + 0.893, + 0.81 + ], + "angle": 0, + "content": "Training configurations. We follow the image and LiDAR data augmentation strategies from MMDetection3D [9] to enlarge the training samples' diversities. AdamW [26] is utilized with a weight decay of 0.05 and a cyclical learning rate schedule [30] for optimization. We take overall 26 training epochs for 3D detection, and 20 epochs for BEV map segmentation, with CBGS [42] to balance the data sampling. MetaBEV is trained on 8 A100 GPUs. For the switched-modality training, the training ratios for camera/LiDAR/both are uniformly set to be \\(1/3\\), \\(1/3\\), and \\(1/3\\), respectively. Further details are available in the appendix." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.818, + 0.774, + 0.833 + ], + "angle": 0, + "content": "4.2. Performance on full modalities" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.84, + 0.893, + 0.901 + ], + "angle": 0, + "content": "We evaluate MetaBEV on 3D object detection and BEV map segmentation, utilizing either single or full modality inputs. Note that the BEV feature map size in MetaBEV is \\(180 \\times 180\\), which is consistent with the BEV query utilized" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8726" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.089, + 0.89, + 0.171 + ], + "angle": 0, + "content": "
MethodsCamera + LidarMissing CameraMissing LiDAR
mAPNDSmIoUmAPNDSmIoUmAPNDSmIoU
TransFusion [1]67.371.2-61.667.4----
BEVFusion [25]68.571.462.761.867.54.10.57.136.7
MetaBEV68.071.570.463.669.253.739.042.654.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.174, + 0.893, + 0.218 + ], + "angle": 0, + "content": "Table 2. Experimental comparisons on extreme sensor missing. MetaBEV is able to totally drop the features from the missing modalities for inference, while others cannot. We attempt to replace the missing features with zero in other works so that they can output results, which are colored as blue. MetaBEV still consistently outperforms prior works when facing extreme sensor absence." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.226, + 0.89, + 0.342 + ], + "angle": 0, + "content": "
MethodsEvaluationLimited Field [-60,60]Missing Objects rate=1.0Beam Reduction 4 beamsView Drop 6 dropsView Noise 6 noiseObstacle Occlusion w occlusion
NDSmIoUNDSmIoUNDSmIoUNDSmIoUNDSmIoUNDSmIoU
BEVFusion [25]zero-shot41.647.262.161.858.355.367.54.166.925.868.645.8
MetaBEV47.061.262.569.257.764.368.343.568.045.270.061.2
BEVFusion [25]in-domain42.655.565.261.951.259.068.352.868.353.169.759.3
MetaBEV54.362.168.569.954.666.469.367.969.267.570.370.2
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.347, + 0.893, + 0.377 + ], + "angle": 0, + "content": "Table 3. Experimental comparisons on sensor corruptions. Texts in blue denote the corruption degree. More detailed results are available in the appendix. MetaBEV consistently outperforms BEVFusion on various sensor corruptions in zero-shot and in-domain tests." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.4, + 0.473, + 0.765 + ], + "angle": 0, + "content": "in BEVFormer, thus being fairly compared. For 3D object detection, results in Tab. 1 show that MetaBEV achieves superior performance with the camera modality, and gets comparable performance to the state-of-the-art with both Li-DAR and multi-modalities. For example, with CenterPoint-3D [38], MetaBEV-C achieves an impressive \\(60.4\\%\\) NDS on nuScenes val set with camera inputs, for LiDAR and multi-modal inputs, MetaBEV gains \\(69.3\\%\\) and \\(71.5\\%\\), respectively, which is comparable to several SoTA methods. We also notice that though MetaBEV exhibits a slightly lower mAP with full-modality inputs, it still achieves superior NDS with improved orientation estimation (\\(27.2\\%\\) vs. \\(30.4\\%\\) mAOE) as well as distance evaluation (\\(28.0\\%\\) vs. \\(28.7\\%\\) mATE) in such the case. Moreover, it is experimentally found that MetaBEV is effective in capturing fine-grained features for dense predictions, e.g., semantic prediction. For single-modality inputs, with only several MLP heads for prediction, MetaBEV achieves a \\(59.3\\%\\) mIoU on cameras, and an impressive \\(64.8\\%\\) mIoU on LiDAR \\((+16.2\\%)\\) higher than BEVFusion [25]). Moreover, results in Tab. 1 show we set a new state-of-the-art (SOTA) performance of \\(70.4\\%\\) mIoU on BEV map segmentation, outperforming the previous best model [2] with \\(+4.7\\%\\) mIoU and the second-best method [25] by \\(+7.7\\%\\) mIoU." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.772, + 0.325, + 0.789 + ], + "angle": 0, + "content": "4.3. Performance on corruption" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.471, + 0.903 + ], + "angle": 0, + "content": "We proceed to evaluate MetaBEV under various sensor failure cases, including complete sensor missing and various sensor corruptions. For the sensor missing, we train MetaBEV with the switched modality scheme, as described in Sec. 3.4. Previous fusion-based approaches, such as BEVFusion [25] and TransFusion [1], heavily rely on multi-modal features and cannot explicitly handle the ab" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.4, + 0.895, + 0.628 + ], + "angle": 0, + "content": "sence of features caused by sensor missing. Nevertheless, we attempt to replace missing modalities with zero-initialized features for them, allowing the prior methods for predictions. Results in Tab. 2 show that MetaBEV demonstrates a stronger anti-corruption ability. Specifically, in case of missing LiDAR, MetaBEV improves \\(+35.5\\%\\) detection NDS and \\(+17.7\\%\\) segmentation mAP upon BEVFusion [25]; when encountering missing cameras, MetaBEV surpasses BEVFusion [25] by \\(+1.7\\%\\) NDS and \\(49.5\\%\\) mIoU. Notably, even when the cameras are missing, MetaBEV still achieves \\(53.7\\%\\) mIoU, surpassing the SoTA LiDAR-Only methods by \\(5.1\\%\\) (i.e., CenterPoint [38]) and \\(9.9\\%\\) (i.e., PointPillars [16]); and when the LiDAR is missing, MetaBEV even outperforms the camera-specific BEVFusion by \\(+1.4\\%\\) NDS \\((42.6\\%\\) v.s. \\(41.2\\%)\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.674, + 0.896, + 0.902 + ], + "angle": 0, + "content": "On the other hand, we conducted both zero-shot and in-domain tests on sensor corruptions. To evaluate the model's abilities in performing with unseen corrupted or missing data, we performed the zero-shot test by directly evaluating a trained model on such data. For the in-domain test, we train MetaBEV on corrupted data with random degrees, and then conduct evaluations on noise data with one specific degree. Tab.3 shows MetaBEV outperforms BEVFusion [25] on 11/12 corruptions on zero-shot evaluation. Moreover, when trained with randomly corrupted data, MetaBEV consistently outperformed BEVFusion. The results indicate that the fusion module, which is composed of CNNs (e.g., BEVFusion), has limited representational capabilities for corrupted data, while our approach leverages the attention mechanism for efficient modeling." + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.958 + ], + "angle": 0, + "content": "8727" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.09, + 0.468, + 0.202 + ], + "angle": 0, + "content": "
mAPNDSmIoU
Detection only67.671.0-
Segmentation only--70.4
H-MoER-MoE
XX64.869.464.7
✓X65.6 (+0.8)69.5 (+0.1)66.3 (+1.6)
X✓65.4 (+0.6)69.8 (+0.4)66.9 (+2.2)
" + }, + { + "type": "table_caption", + "bbox": [ + 0.078, + 0.212, + 0.471, + 0.242 + ], + "angle": 0, + "content": "Table 4. We experiment on two kinds of MoE structures for Multi-Task Learning, and both show significant advantages." + }, + { + "type": "table", + "bbox": [ + 0.081, + 0.252, + 0.468, + 0.306 + ], + "angle": 0, + "content": "
Method#Params.(M)mAPNDS#Params.(M)mIoU
BEVFusion40.868.571.443.162.7
BEVFusion (Heavy)54.167.270.156.165.9
MetaBEV53.568.071.555.970.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.316, + 0.471, + 0.345 + ], + "angle": 0, + "content": "Table 5. Comparisons on 3D detection and BEV-Map segmentation." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.365, + 0.398, + 0.383 + ], + "angle": 0, + "content": "4.4. Performance in Multi-Task Learning" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.389, + 0.473, + 0.706 + ], + "angle": 0, + "content": "Tab. 4 presents the results of our multi-task learning (MTL) experiments for 3D object detection and BEV map segmentation. We begin with the framework designed for independent single-task learning with distinct task-specific heads and loaded a set of weights trained on multi-modal detection as pretrain. The model achieves \\(69.4\\%\\) NDS and \\(64.7\\%\\) mIoU for detection and segmentation, respectively, which is already a state-of-the-art performance. In light of this, we implement an MoE structure to help alleviate the gradient-conflict problem in MTL. Intuitively, we introduce a routing-based MoE structure, referred to as \\(\\mathrm{RM}^2\\mathrm{oE}\\), to replace the vanilla MLP layer. This implementation results in a remarkable improvement of \\(0.4\\%\\) NDS in detection and \\(2.2\\%\\) mIoU in segmentation. Considering the additional computation required by the routing mechanisms, we propose to further experiment on a simplified version \\(\\mathrm{HM}^2\\mathrm{oE}\\) where the number of experts is adjusted to match that of the tasks, and the routing function is removed. We find it still achieves a notable improvement of \\(0.1\\%\\) NDS and \\(1.6\\%\\) mIoU. Upon the evaluation results, both implementations mitigate performance degradation in MTL to some extent." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.715, + 0.242, + 0.73 + ], + "angle": 0, + "content": "4.5. Ablation Studies" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.738, + 0.47, + 0.8 + ], + "angle": 0, + "content": "Setup. We present the ablation studies for analyzing the network architectures and training schemes. All the ablation studies are performed on nuScenes validation set, with the training configurations set as default in Sec. 4.1." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.81, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Network Configurations. We first explore the optimal architectures of the BEV-Evolving Decoder. Specifically, we analyze three components, including the combination of the layers, reference points number (\\(p\\) in Eq.1), and expert number (\\(E\\) in Eq.2). Our findings in Tab. 6a indicate that a few layers of cross-attention are sufficient to produce effec" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.409 + ], + "angle": 0, + "content": "tive predictions while stacking more cross-attention layers does not necessarily enhance the model's capacities (68.3% and 68.2% NDS for 6 and 8 cross-attention layers, respectively). The same findings also suit the reference points number, where increasing the sampling points does not necessarily lead to better performance, as shown in Tab. 6b. On the contrary, we discovered that simply adding two layers of self-attention after the cross-attention layers significantly improve the prediction performance by +1.1% NDS in Tab. 6a. As mentioned in Sec. 3.2, the hybrid designs capture both intra- and inter-correlations simultaneously, resulting in complementary modeling. Moreover, in Tab. 6c, we discover that a larger model capacity (i.e., incorporating more experts) can effectively alleviate the performance drop in 3D detection and map segmentation. Specifically, MetaBEV equipped with 2/8 expert (i.e. activating the 2 experts with the highest scores from a total of 8 experts.) achieves the best performance compared to other configurations (66.9% mIoU and 69.8% NDS), while \\(\\mathrm{HM}^2\\mathrm{oE}\\) is unaffected due to the fixed number of experts being equivalent to the number of tasks." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.421, + 0.892, + 0.753 + ], + "angle": 0, + "content": "Do More Parameters Guarantee Improved Model Accuracy? We note that incorporating deformable attention does introduce additional parameters to MetaBEV; however, this increment is minimal and acceptable (i.e., 54M v.s. 41M) in relation to its functional capabilities (addressing sensor failures). Besides, compared with BEVFusion, though MetaBEV achieves modest advancements on 3D detection (+0.1% NDS), the improvement on map segmentation is remarkably significant (+7.7% mIoU), which indicates the deformable attention facilitates more in per-pixel perception. To conduct a fair comparison, we consistently introduce more fusion layers to BEVFusion. Results in Tab. 5 demonstrate that increasing parameters of BEVFusion yields an improved performance in map segmentation, while a reduction in 3D detection accuracy. The decreased performance for 3D detection may be attributed to the challenging convergence for the larger parameters. Furthermore, it is observed that BEVFusion performs poorly in both 3D detection and map segmentation when compared to MetaBEV with the same parameter amount. This finding highlights the fact that having more model parameters does not guarantee improved model accuracy." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Switched Modality Training. For the training strategy, using switched modality scheme to simulate the sensors missing, though simple, is the key to enabling MetaBEV with robust performance on completely sensor-failure scenarios. In Tab. 6d, comparing with the vanilla full-modality training approach, our proposed training strategy yields significant improvements on 3D detection by \\(+32.8\\%\\) NDS and \\(+1.0\\%\\) NDS, and improvements on map segmentation by \\(+17.9\\%\\) mIoU and \\(+16.7\\%\\) mIoU under LiDAR-missing" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8728" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.136, + 0.089, + 0.344, + 0.182 + ], + "angle": 0, + "content": "
LayersmAP/NDS
4 cross61.7/67.0
6 cross63.0/68.3
8 cross62.5/68.2
2 self+4 cross64.2/69.3
" + }, + { + "type": "table_caption", + "bbox": [ + 0.136, + 0.187, + 0.343, + 0.2 + ], + "angle": 0, + "content": "(a) The number of self/Cross-layer" + }, + { + "type": "table", + "bbox": [ + 0.388, + 0.089, + 0.544, + 0.181 + ], + "angle": 0, + "content": "
PointsmAP/NDS
462.3/67.9
862.7/68.2
1262.3/68.0
1662.3/68.1
" + }, + { + "type": "table_caption", + "bbox": [ + 0.363, + 0.187, + 0.568, + 0.201 + ], + "angle": 0, + "content": "(b) The number of reference points" + }, + { + "type": "table", + "bbox": [ + 0.59, + 0.089, + 0.835, + 0.181 + ], + "angle": 0, + "content": "
ExpertsmAP/NDSmIoU
1/2 Expert65.8/69.863.3
1/4 Expert64.9/69.565.9
1/8 Expert65.4/69.766.4
2/8 Expert65.4/69.866.9
" + }, + { + "type": "table_caption", + "bbox": [ + 0.657, + 0.187, + 0.768, + 0.201 + ], + "angle": 0, + "content": "(c) Expert number" + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.202, + 0.89, + 0.293 + ], + "angle": 0, + "content": "
TaskMetricsVanilla trainingSwitched Modality Training
Lidar-MissingCamera-MissingFullLidar-MissingCamera-MissingFull
3D detectionNDS9.868.271.042.6 (+32.8)69.2 (+1.0)71.5 (+0.5)
mAP2.962.467.439.0 (+36.1)63.6 (+1.2)68.0 (+0.6)
BEV-Map SegmentationmIoU36.527.070.454.4 (+17.9)53.7 (+16.7)68.5 (-1.9)
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.076, + 0.297, + 0.893, + 0.326 + ], + "angle": 0, + "content": "(d) Evaluation of the NuScenes val dataset when Cameras or LiDAR totally fail. We test the performance with the switched modality training on both 3D detection and BEV-map segmentation tasks." + }, + { + "type": "table_footnote", + "bbox": [ + 0.076, + 0.329, + 0.878, + 0.345 + ], + "angle": 0, + "content": "Table 6. Ablation studies for the model architectures and training strategy. Default settings are marked in gray in (a), (b), and (c)." + }, + { + "type": "list", + "bbox": [ + 0.076, + 0.297, + 0.893, + 0.345 + ], + "angle": 0, + "content": null + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.372, + 0.47, + 0.434 + ], + "angle": 0, + "content": "and camera-missing scenarios, respectively. More intriguingly, we find that the switched modality training could even enhance the model performance on full modalities, rising from \\(71.0\\%\\) NDS to \\(71.5\\%\\) NDS on 3D detection." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.447, + 0.196, + 0.463 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.474, + 0.473, + 0.671 + ], + "angle": 0, + "content": "In this paper, we present a novel framework, named MetaBEV, for the purpose of solving sensor failures in the bird's-eye view (BEV) 3D detection and map segmentation. Our method integrates modal-specific layers into the cross-modal attention layer to enhance the fusion process, achieving appealing performance on full-modality inputs, and meanwhile MetaBEV effectively alleviates the significant performance degradation that is often caused by corrupted or missing sensor signals. We also introduce \\(\\mathbf{M}^2\\mathrm{oE}\\) to handle potential conflicts between tasks. We hope that MetaBEV will provide a more focused and effective approach for investigating sensor-failure scenarios in the autonomous driving field." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.685, + 0.47, + 0.822 + ], + "angle": 0, + "content": "Limitations. Though we adopted the deformable attention [43] for efficiency, it unavoidably leads to a slight increase in network parameters compared to the lightweight solutions [25, 22]. Despite this, the benefits of mitigating sensor failures are highly desirable, and the additional computational overhead may be deemed acceptable. We acknowledge that lightweight networks could be an avenue for future research, potentially involving techniques such as network pruning, token reduction, etc." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.471, + 0.903 + ], + "angle": 0, + "content": "Acknowledgement. This paper is partially supported by the National Key R&D Program of China No.2022ZD0161000 and the General Research Fund of Hong Kong No.17200622." + }, + { + "type": "title", + "bbox": [ + 0.502, + 0.371, + 0.597, + 0.387 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.397, + 0.893, + 0.467 + ], + "angle": 0, + "content": "[1] Xuyang Bai, Zeyu Hu, Xinge Zhu, Qingqiu Huang, Yilun Chen, Hongbo Fu, and Chiew-Lan Tai. Transfusion: Robust lidar-camera fusion for 3d object detection with transformers. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.469, + 0.894, + 0.539 + ], + "angle": 0, + "content": "[2] Shubhankar Borse, Marvin Klingner, Varun Ravi Kumar, Hong Cai, Abdulaziz Almuzairee, Senthil Yogamani, and Fatih Porikli. X-align: Cross-modal cross-view alignment for bird's-eye-view segmentation. In IEEE/CVF Winter Conference on Applications of Computer Vision, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.541, + 0.895, + 0.611 + ], + "angle": 0, + "content": "[3] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.613, + 0.894, + 0.669 + ], + "angle": 0, + "content": "[4] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In European Conference on Computer Vision, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.671, + 0.894, + 0.727 + ], + "angle": 0, + "content": "[5] Runjian Chen, Yao Mu, Runsen Xu, Wenqi Shao, Chenhan Jiang, Hang Xu, Zhenguo Li, and Ping Luo. Co^3: Cooperative unsupervised 3d representation learning for autonomous driving. arXiv preprint arXiv:2206.04028, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.729, + 0.895, + 0.785 + ], + "angle": 0, + "content": "[6] Xiaozhi Chen, Huimin Ma, Ji Wan, Bo Li, and Tian Xia. Multi-view 3d object detection network for autonomous driving. In Proceedings of the IEEE conference on Computer Vision and Pattern Recognition, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.788, + 0.893, + 0.83 + ], + "angle": 0, + "content": "[7] Xuanyao Chen, Tianyuan Zhang, Yue Wang, Yilun Wang, and Hang Zhao. Futr3d: A unified sensor fusion framework for 3d detection. arXiv preprint arXiv:2203.10642, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.832, + 0.894, + 0.902 + ], + "angle": 0, + "content": "[8] Aakanksha Chowdhery, Sharan Narang, Jacob Devlin, Maarten Bosma, Gaurav Mishra, Adam Roberts, Paul Barham, Hyung Won Chung, Charles Sutton, Sebastian Gehrmann, et al. Palm: Scaling language modeling with pathways. arXiv preprint arXiv:2204.02311, 2022." + }, + { + "type": "list", + "bbox": [ + 0.509, + 0.397, + 0.895, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8729" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.092, + 0.468, + 0.147 + ], + "angle": 0, + "content": "[9] MMDetection3D Contributors. MMDetection3D: OpenMMLab next-generation platform for general 3D object detection. https://github.com/open-mmlab/mmdetection3d, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.149, + 0.468, + 0.217 + ], + "angle": 0, + "content": "[10] Danny Driess, Fei Xia, Mehdi SM Sajjadi, Corey Lynch, Aakanksha Chowdhery, Brian Ichter, Ayzaan Wahid, Jonathan Tompson, Quan Vuong, Tianhe Yu, et al. Palme: An embodied multimodal language model. arXiv preprint arXiv:2303.03378, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.219, + 0.468, + 0.285 + ], + "angle": 0, + "content": "[11] Chongjian Ge, Youwei Liang, Yibing Song, Jianbo Jiao, Jue Wang, and Ping Luo. Revitalizing cnn attention via transformers in self-supervised visual representation learning. Advances in Neural Information Processing Systems, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.288, + 0.468, + 0.342 + ], + "angle": 0, + "content": "[12] Chongjian Ge, Jiangliu Wang, Zhan Tong, Shoufa Chen, Yibing Song, and Ping Luo. Soft neighbors are positive supporters in contrastive visual representation learning. arXiv preprint arXiv:2303.17142, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.344, + 0.468, + 0.412 + ], + "angle": 0, + "content": "[13] Yihan Hu, Jiazhi Yang, Li Chen, Keyu Li, Chonghao Sima, Xizhou Zhu, Siqi Chai, Senyao Du, Tianwei Lin, Henhai Wang, et al. Planning-oriented autonomous driving. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.414, + 0.468, + 0.467 + ], + "angle": 0, + "content": "[14] Tengteng Huang, Zhe Liu, Xiwu Chen, and Xiang Bai. Epnet: Enhancing point features with image semantics for 3d object detection. In European Conference on Computer Vision, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.47, + 0.468, + 0.537 + ], + "angle": 0, + "content": "[15] Sebastian Jasczur, Aakanksha Chowdhery, Afroz Mohiuddin, Lukasz Kaiser, Wojciech Gajewski, Henryk Michalewski, and Jonni Kanerva. Sparse is enough in scaling transformers. Advances in Neural Information Processing Systems, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.539, + 0.468, + 0.594 + ], + "angle": 0, + "content": "[16] Alex H Lang, Sourabh Vora, Holger Caesar, Lubing Zhou, Jiong Yang, and Oscar Beijbom. Pointpillars: Fast encoders for object detection from point clouds. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.596, + 0.468, + 0.663 + ], + "angle": 0, + "content": "[17] Dmitry Lepikhin, HyoukJoong Lee, Yuanzhong Xu, Dehao Chen, Orhan First, Yanping Huang, Maxim Krikun, Noam Shazeer, and Zhifeng Chen. Gshard: Scaling giant models with conditional computation and automatic sharding. International Conference on Learning Representations, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.665, + 0.468, + 0.718 + ], + "angle": 0, + "content": "[18] Yanwei Li, Yilun Chen, Xiaojuan Qi, Zeming Li, Jian Sun, and Jiaya Jia. Unifying voxel-based representation with transformer for 3d object detection. arXiv preprint arXiv:2206.00630, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.721, + 0.468, + 0.802 + ], + "angle": 0, + "content": "[19] Yingwei Li, Adams Wei Yu, Tianjian Meng, Ben Caine, Jiquan Ngiam, Daiyi Peng, Junyang Shen, Yifeng Lu, Denny Zhou, Quoc V Le, et al. Deepfusion: Lidar-camera deep fusion for multi-modal 3d object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.804, + 0.468, + 0.872 + ], + "angle": 0, + "content": "[20] Yingwei Li, Adams Wei Yu, Tianjian Meng, Ben Caine, Ji-quan Ngiam, Daiyi Peng, Junyang Shen, Yifeng Lu, Denny Zhou, Quoc V Le, et al. Deepfusion: Lidar-camera deep fusion for multi-modal 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.081, + 0.874, + 0.468, + 0.9 + ], + "angle": 0, + "content": "[21] Zhiqi Li, Wenhai Wang, Hongyang Li, Enze Xie, Chonghao Sima, Tong Lu, Yu Qiao, and Jifeng Dai. Bevformer:" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.468, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "Learning bird's-eye-view representation from multi-camera images via spatiotemporal transformers. In European Conference on Computer Vision, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.136, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[22] Tingting Liang, Hongwei Xie, Kaicheng Yu, Zhongyu Xia, Zhiwei Lin, Yongtao Wang, Tao Tang, Bing Wang, and Zhi Tang. Bevfusion: A simple and robust lidar-camera fusion framework. arXiv preprint arXiv:2205.13790, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.193, + 0.892, + 0.247 + ], + "angle": 0, + "content": "[23] Tsung-Yi Lin, Piotr Dólar, Ross Girshick, Kaiming He, Bharath Hariharan, and Serge Belongie. Feature pyramid networks for object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.249, + 0.892, + 0.316 + ], + "angle": 0, + "content": "[24] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In IEEE/CVF International Conference on Computer Vision, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.319, + 0.892, + 0.374 + ], + "angle": 0, + "content": "[25] Zhijian Liu, Haotian Tang, Alexander Amini, Xinyu Yang, Huizi Mao, Daniela Rus, and Song Han. Bevfusion: Multi-task multi-sensor fusion with unified bird's-eye view representation. arXiv preprint arXiv:2205.13542, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.376, + 0.892, + 0.403 + ], + "angle": 0, + "content": "[26] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. arXiv preprint arXiv:1711.05101, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.405, + 0.892, + 0.446 + ], + "angle": 0, + "content": "[27] Jonah Philion and Sanja Fidler. Lift, splat, shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3d. In European Conference on Computer Vision, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.448, + 0.892, + 0.503 + ], + "angle": 0, + "content": "[28] Noam Shazeer, Azalia Mirhoseini, Krzysztof Maziarz, Andy Davis, Quoc Le, Geoffrey Hinton, and Jeff Dean. Outrageously large neural networks: The sparsely-gated mixture-of-experts layer. arXiv preprint arXiv:1701.06538, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.505, + 0.892, + 0.545 + ], + "angle": 0, + "content": "[29] Vishwanath A Sindagi, Yin Zhou, and Oncel Tuzel. Mvxnet: Multimodal voxelnet for 3d object detection. In International Conference on Robotics and Automation, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.547, + 0.892, + 0.588 + ], + "angle": 0, + "content": "[30] Leslie N Smith. Cyclical learning rates for training neural networks. In IEEE/CVF Winter Conference on Applications of Computer Vision, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.591, + 0.892, + 0.645 + ], + "angle": 0, + "content": "[31] Sourabh Vora, Alex H Lang, Bassam Helou, and Oscar Beijbom. Pointpainting: Sequential fusion for 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.647, + 0.892, + 0.701 + ], + "angle": 0, + "content": "[32] Chunwei Wang, Chao Ma, Ming Zhu, and Xiaokang Yang. Pointaugmenting: Cross-modal augmentation for 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.704, + 0.892, + 0.758 + ], + "angle": 0, + "content": "[33] Xin Wang, Fisher Yu, Lisa Dunlap, Yi-An Ma, Ruth Wang, Azalia Mirhoseini, Trevor Darrell, and Joseph E Gonzalez. Deep mixture of experts via shallow embedding. In Uncertainty in artificial intelligence, pages 552-562, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.76, + 0.892, + 0.815 + ], + "angle": 0, + "content": "[34] Yue Wang, Vitor Campagnolo Guizilini, Tianyuan Zhang, Yilun Wang, Hang Zhao, and Justin Solomon. Detr3d: 3d object detection from multi-view images via 3d-to-2d queries. In Conference on Robot Learning, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.817, + 0.892, + 0.858 + ], + "angle": 0, + "content": "[35] Barret Zoph William Fedus and Noam Shazeer. Switch transformers: Scaling to trillion parameter models with simple and efficient sparsity. Computer Research Repository, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.86, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[36] Enze Xie, Zhiding Yu, Daquan Zhou, Jonah Philion, Anima Anandkumar, Sanja Fidler, Ping Luo, and Jose M Alvarez. M^2bev: Multi-camera joint 3d detection and segmentation" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8730" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.469, + 0.12 + ], + "angle": 0, + "content": "with unified birds-eye view representation. arXiv preprint arXiv:2204.05088, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.469, + 0.177 + ], + "angle": 0, + "content": "[37] Brandon Yang, Gabriel Bender, Quoc V Le, and Jiquan Ngiam. Condconv: Conditionally parameterized convolutions for efficient inference. Advances in Neural Information Processing Systems, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.179, + 0.469, + 0.22 + ], + "angle": 0, + "content": "[38] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Center-based 3d object detection and tracking. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.222, + 0.469, + 0.262 + ], + "angle": 0, + "content": "[39] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Multimodal virtual point 3d detection. Advances in Neural Information Processing Systems, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.264, + 0.469, + 0.332 + ], + "angle": 0, + "content": "[40] Kaicheng Yu, Tang Tao, Hongwei Xie, Zhiwei Lin, Zhongwei Wu, Zhongyu Xia, Tingting Liang, Haiyang Sun, Jiong Deng, Dayang Hao, et al. Benchmarking the robustness of lidar-camera fusion for 3d object detection. arXiv preprint arXiv:2205.14951, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.334, + 0.469, + 0.376 + ], + "angle": 0, + "content": "[41] Yin Zhou and Oncel Tuzel. Voxelnet: End-to-end learning for point cloud based 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.378, + 0.469, + 0.431 + ], + "angle": 0, + "content": "[42] Benjin Zhu, Zhengkai Jiang, Xiangxin Zhou, Zeming Li, and Gang Yu. Class-balanced grouping and sampling for point cloud 3d object detection. arXiv preprint arXiv:1908.09492, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.434, + 0.469, + 0.488 + ], + "angle": 0, + "content": "[43] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable detr: Deformable transformers for end-to-end object detection. arXiv preprint arXiv:2010.04159, 2020." + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.488 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.514, + 0.956 + ], + "angle": 0, + "content": "8731" + } + ] +] \ No newline at end of file diff --git a/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/5204095b-1c9c-4150-9f9c-b1c27fdd82da_origin.pdf b/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/5204095b-1c9c-4150-9f9c-b1c27fdd82da_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..f6b43182d5d1133a94c38ed54c6511ed1251867b --- /dev/null +++ b/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/5204095b-1c9c-4150-9f9c-b1c27fdd82da_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:4d086f655801c940f5ae89dc211e3ff4fd8f13191040d0a2138be259a9249bf0 +size 2402637 diff --git a/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/full.md b/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/full.md new file mode 100644 index 0000000000000000000000000000000000000000..12c7db1f3a5f44478637b1f4e42761acdf2323da --- /dev/null +++ b/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/full.md @@ -0,0 +1,266 @@ +# MetaBEV: Solving Sensor Failures for 3D Detection and Map Segmentation + +Chongjian Ge $^{1*}$ Junsong Chen $^{3,1*}$ Enze Xie $^{2\dagger}$ Zhongdao Wang $^{2}$ + +Lanqing Hong² Huchuan Lu³ Zhenguo Li² Ping Luo¹,⁴† + +1The University of Hong Kong 2Huawei Noah's Ark Lab + +$^{3}$ Dalian University of Technology $^{4}$ Shanghai AI Laboratory + +rhettgee $@$ connect.hku.hk jschen@mail.dlut.edu.cn lhchuan@dlut.edu.cn + +{xie.enze, wangzhongdao, honglanqing, li.zhenguo}@huawei.com pluo@cs.hku.hk + +Project page: https://chongjiange.github.io/metabev.html + +![](images/d22cc19f55915b84edf7a6856dd242f5f43ce0741ea6e2f353a506f4b9bc47ff.jpg) +Figure 1. Selected 3D prediction results under various sensor failures. MetaBEV shows stronger robustness on both map segmentation and 3D detection compared to the representative multi-modal method, e.g., BEVFusion [25]. Notably, in case of an entire sensor absent (e.g., Camera or LiDAR), MetaBEV provides satisfactory outcomes while existing methods fail to. Top two rows: 3D prediction results. Bottom row: the corresponding ground truths. + +# Abstract + +Perception systems in modern autonomous driving vehicles typically take inputs from complementary multi-modal sensors, e.g., LiDAR and cameras. However, in real-world applications, sensor corruptions and failures lead to inferior performances, thus compromising autonomous safety. In this paper, we propose a robust framework, called MetaBEV, to address extreme real-world environments, involving overall six sensor corruptions and two extreme sensor-missing situations. In MetaBEV, signals from multiple sensors are first processed by modal-specific encoders. Subsequently, a set of dense BEV queries are initialized, termed meta-BEV. These queries are then processed iteratively by a BEV-Evolving decoder, which selectively aggregates deep features from either LiDAR, cameras, or both + +modalities. The updated BEV representations are further leveraged for multiple 3D prediction tasks. Additionally, we introduce a new $M^2 oE$ structure to alleviate the performance drop on distinct tasks in multi-task joint learning. Finally, MetaBEV is evaluated on the nuScenes dataset with 3D object detection and BEV map segmentation tasks. Experiments show MetaBEV outperforms prior arts by a large margin on both full and corrupted modalities. For instance, when the LiDAR signal is missing, MetaBEV improves $35.5\%$ detection NDS and $17.7\%$ segmentation mIoU upon the vanilla BEVFusion [25] model; and when the camera signal is absent, MetaBEV still achieves $69.2\%$ NDS and $53.7\%$ mIoU, which is even higher than previous works that perform on full-modalities. Moreover, MetaBEV performs moderately against previous methods in both canonical perception and multi-task learning settings, refreshing state-of-the-art nuScenes BEV map segmentation with $70.4\%$ mIoU. + +# 1. Introduction + +Perceiving the surrounding environment is a fundamental capability of autonomous driving systems. In pursuit of higher perceptual accuracy, prior works make significant efforts in designing stronger task-specific modules [41, 16, 21], cultivating effective training paradigms [5], leveraging multi-modalities [25, 22, 7], etc. Among all these, the multi-sensors fusion strategy exhibits significant advantages in achieving stronger perception abilities [31, 39, 25, 1], thus being widely explored in both academia and industry. While the majority of works focus on achieving optimal performance on ideal multi-modal inputs for a single specific task, they unintentionally neglect how the designed models perform with sensor failures, which are commonly encountered and inevitable in real-world applications. + +To alleviate performance drop on sensor failures, previous works encounter two challenges as follows. 1) Features misalignment: Existing fusion methods typically utilize CNNs and features concatenation for fusion [25, 22]. The pixel-level position correlation is consistently imposed, giving rise to multi-modal features misalignment, especially when geometric-related noises are introduced. This issue could be attributed to the intrinsic characteristics of CNNs, which exhibit limitations in long-range perception and adaptive attention to input features. 2) Heavily reliant on complete modalities: Prior arts generate the fused BEV features using either query-indexing or channel-wise fusion manners. Query-indexing methods [29, 31, 32, 14] typically rely on LiDAR and 2D Camera features for mutual querying, while channel-wise fusion approaches [25, 22] are inevitable to involve element-wise operations (e.g. element-sum) for feature merging. Both fusion strategies are heavily dependent on complete modality inputs and lead to inferior perception performance encountering extreme sensor failures such as LiDAR-missing or Cameras-missing, thus being limited in the practical applications. + +In this research, we propose MetaBEV to tackle the above features misalignment and full-modality dependence problems through modality-arbitrary and task-agnostic learning in the unified bird's-eye view (BEV) representation space [18]. We identify the major bottleneck in modality-dependent methods is the lack of designs that enable independent fusion of different modalities by the fusion module. Therefore, we present a modality-arbitrary BEV-Evolving decoder, which leverages cross-modal attention to correlate the learnable meta-BEV queries with either a single camera-BEV feature, LiDAR-BEV feature, or both to eliminate the bottleneck. Finally, we apply a few task-specific heads to support different 3D perception predictions. + +Except for the canonical perception (on no corrupted sensors), we also evaluate MetaBEV on overall six sensor corruptions (Limited Field (LF), Beams Reduction (BR), Missing Objects (MO), View Drop (VD), View Noise (VN), + +![](images/03880d9e863487a61412f4b354f6d57ee44cc5a52e7c41df2dbd8a9c9d1ca746.jpg) +Figure 2. MetaBEV shows stronger robustness on missing sensors. We perform representative methods with full/missing modalities on both map segmentation (the left part) and 3D detection (the right part). Results show MetaBEV can mitigate the performance drop on input absence. Quantitatively, when facing missing cameras, MetaBEV still achieves $53.7\%$ mIoU, which outperforms the representative method (i.e., BEVFusion [25]), by $+49.6\%$ mIoU, and is even better than MVP [39] performed on full-modalities. The superior performance could also be found on 3D detection tasks. + +Obstacle Occlusion (OO)) and two sensor-missing scenarios (Missing LiDAR (ML) and Missing Camera (MC)). Compared with prior works, MetaBEV performs more robustly as depicted in Fig. 1. For example, it achieves $69.2\%$ NDS and $42.6\%$ NDS on detection when totally missing the cameras or LiDAR, respectively. For map segmentation, when total cameras absence occurs, MetaBEV could still achieve better performance compared to the work trained on multi-modalities (i.e., $54.7\%$ v.s. MVP's $49.0\%$ mIoU [39]). Besides, the attention-based MetaBEV exhibits inherent robustness against multiple heavy corruptions with zero-shot and in-domain tests. For instance, as shown in Tab. 3, even missing $66.6\%$ of LiDAR points, MetaBEV still achieves $55\%$ NDS, outperforming the competitor by $+11.7\%$ . + +Moreover, considering the limited computational resource in practice, using a single framework with shared parameters for different tasks is more efficient than using separate frameworks for multiple tasks. However, the task conflicts in the joint learning of detection and segmentation often lead to severe performance drop [36, 21, 25], and existing methods rarely analyze and design for multi-task learning (MTL). We incorporate MetaBEV with a flexible module based on Multi-Task Mixture of Experts $(\mathbf{M}^2\mathrm{oE})$ to demonstrate one possible solution for MTL and hope to stimulate further research in this area. + +The appealing advantages of MetaBEV are concluded: + +1. MetaBEV is a novel BEV perception framework for 3D object detection and BEV map segmentation, which can maintain resilient performance under arbitrary sensor input. Plenty of real-world sensor corruptions are formulated as well as methodically experimented with and analyzed to verify its robustness. + +2. MetaBEV involves the $\mathbf{M}^2\mathrm{oE}$ structures to alleviate tasks conflict when performing 3D detection and segmentation tasks with the same trained weights. +3. MetaBEV achieves state-of-the-art performance on nuScenes dataset [3]. It's the first method designed for both sensor failures and tasks conflict. We hope MetaBEV will facilitate future research. + +# 2. Related Work + +# 2.1. LiDAR-Camera Fusion + +In 3D perception tasks, the effectiveness of multi-sensor fusion is notable. Therefore, researchers have focused on better combining geometric-centric point clouds and semantic-centric images. Existing methods mainly focus on three aspects: proposal-level [6], point-level [7, 1, 19], and feature-level [25, 22]. While attempting to combine multiple modalities, existing approaches typically adopt similar fusion strategies, including query-indexing fusion [1] and channel-wise fusion [25, 22]. Though showing effective in full-modality input, the above fusion manners usually associate multi-modal features tightly among points or pixels, causing features in these methods to be susceptible to spatial misalignment issues and suffering from system collapses due to sensor missing. In our work, we explore an approach that can handle arbitrary modality freely to mitigate the above limitations. + +# 2.2. Sensors-Failure Perception + +Sensor failures can significantly impact the accuracy of 3D perception, thereby jeopardizing the safety of autonomous driving. Therefore, conducting research on sensor failures is of utmost practical importance. Prior arts have made preliminary attempts to propose robust frameworks that address specific sensor failure scenarios on a case-by-case basis. These scenarios include camera-views drop [1], changes in illumination conditions [25, 7, 1], noisy inputs [20], and etc. More recently, [40] provided a comprehensive benchmark for verifying the robustness of methods mainly on sensor degradation. While previous works mainly focus on sensor corruptions, sensor absence is rarely noticed. In this work, we propose a novel perception framework that analyzes not only the aspects of sensor corruptions but also sensor absence comprehensively. + +# 2.3. Multi-Task Learning + +Multi-task learning denotes performing multiple task predictions with one set of trained weights, which appeals to the research community for its practical values, such as the complementary performance, less computational cost, etc. However, multi-task learning can also be challenging, as the model must learn to balance various objectives of + +each task and avoid tasks conflict. In 3D perception, the tasks conflict has been proven by $\mathbf{M}^2\mathrm{BEV}$ [36] and BEVFormer [21], which both perform joint training on camera-only 3D object detection and BEV map segmentation. It is empirically found that joint training leads to severe accuracy degradation on each single task. Prior arts do not address the issues effectively due to their unified models and usually solve the problems from the learning perspective. For example, UniAD [13] adopts multiple training stages to adjust the overall network module by module to avoid gradient conflicts in multi-task learning, which is not end-to-end and can not be optimized layer-by-layer to adjust gradients. Inspired by Mixture-of-Expert (MoE), which is specially designed for large language model in the Natural Language Processing [35, 17, 15, 37, 33] and self-supervised field [8, 11, 12, 10], we introduce a robust fusion module with a new $\mathbf{M}^2\mathrm{oE}$ -FFN layer. The main purpose is to mitigate the gradient conflict between detection and segmentation to achieve a more balanced performance. MetaBEV is the first framework introducing MoE into 3D object detection and BEV map segmentation as a multi-modal, multitask, and robust approach. + +# 3. MetaBEV Method + +We introduce a new baseline, which targets solving a range of sensor failures on 3D object detection and BEV map segmentation tasks. As opposed to existing perception methods that heavily rely on the complete sensor inputs, we connect different modalities through a parameterized metaBEV query and perform cross-modal attention to integrate both semantic and geometry representations from cameras and LiDAR. As shown in Figure 3, the overall pipeline consists of a multi-modalities feature encoder, a BEV-Evolving decoder with cross-modal deformable attention, and task-specific heads. Architecture designs are detailed as follows. + +# 3.1. BEV Feature Encoder Overview + +MetaBEV generates fused features in the BEV space, as BEV representation provides a solution to combine image features with insufficient geometric knowledge and Li-DAR features lacking semantic understanding in a unified domain, allowing for complementary fusion. Additionally, the regularity of the BEV feature facilitates the effective integration of various advanced task heads, which could benefit plenty of perception tasks. + +Camera/LiDAR to BEV. We build our multi-modal feature encoder based on the state-of-the-art perception method BEVFusion [25], which takes multi-view-images and LiDAR-points pair as input and transforms the camera features into BEV space with depth prediction and geometric projection, respectively. Specifically, we adopt a camera backbone $\phi_c(\cdot)$ to generate $N$ -view 2D image representations $F_{c}^{i}, i \in [1,2,\dots ,N]$ . Then, following LSS [27], we + +![](images/9fc992a5b13f3c12e2bb80e36fe0b5af602b4905e0ab32f6a1225262e4717f6a.jpg) +Figure 3. An overview of MetaBEV framework. The multi-modal inputs are separately processed by the camera encoder $\phi_c(\cdot)$ and LiDAR encoder $\phi_l(\cdot)$ to produce the BEV representations $B_{c}, B_{l}$ . To generate the fused BEV features, a BEV-Evolving decoder takes multi-modal BEV representations and an externally initialized meta-BEV feature (as a query feature) for correlation computation. Task-specific heads take the fused features for 3D detection. + +scatter the dense feature $F_{c}^{i}$ into discrete 3D space and compress the generated 3D voxel features $V_{c} \in \mathbb{R}^{D \times C \times X \times Y}$ into the camera BEV representations $B_{c} \in \mathbb{R}^{C \times X \times Y}$ with the pillar format [25], where $D, C, (X, Y)$ denote the depth, dimension and spatial resolution of BEV feature, respectively. As for the LiDAR points, voxelization and sparse 3D convolutions $\phi_{l}(\cdot)$ are utilized for encoding LiDAR BEV representation $B_{l}$ . + +Subsequently, Previous works [25, 22] usually involve concatenating and CNN-based feature fusion, which may cause significant performance drop under sensor corruptions or even system collapse when sensor failures occur. As mentioned in Sec. 1, CNNs exhibit limited effectiveness in large-corruption of input modality (due to the local-aggregation characteristic) and are inappropriate to deal with the absent input modality caused by sensor missing (due to the weight-sharing modeling). We solve the above challenges by introducing BEV-Evolving Decoder as follows. + +# 3.2. BEV-Evolving Decoder + +The BEV-Evolving decoder consists of three key components: the cross-modal attention layers, the self-attention layers, and the plug-and-play $\mathbf{M}^2\mathrm{oE}$ blocks. The above two components facilitate fusing arbitrary modalities, while the $\mathbf{M}^2\mathrm{oE}$ blocks are designed for mitigating the tasks conflict. Cross-Modal Attention Layer. We first initialize a set of dense BEV queries, each representing the feature within a specific spatial grid, termed meta-BEV $(B_{m})$ . $B_{m}$ is added with position embeddings (PE) and then correlates with either a camera BEV feature $(B_{c})$ , LiDAR BEV feature $(B_{l})$ or both. To improve the computational efficiency, we adopt deformable attention $\mathrm{DAttn}(\cdot)$ [43]. However, the original implementation $\mathrm{DAttn}(\cdot)$ is not suitable for processing arbitrary inputs, as it utilizes one unified MLP layer to sample reference points $\Delta p$ and attention weights $A$ . We then introduce model-specific MLP layers (i.e., C-MLP for cameras + +and L-MLP for LiDAR in Fig. 4 III) for the flexibility of fusion. Given any input BEV representations $x \in [B_c, B_l]$ as value features, we first generate model-specific sampling offsets $\Delta p^x$ and attention weights $A^x$ from query $B_m$ . We then combine the pixel coordinates of $B_m$ and the corresponding offsets $\Delta p^x$ to locate the sampled value features. After re-scaling the sampled features by the attention weights $A^x$ , meta-BEV is updated from informative sensor features. The overall process is formulated in the following, + +$$ +\begin{array}{l} \mathrm {D A t t n} \left(B _ {m}, p, x\right) = \\ \sum_ {m = 1} ^ {M} W _ {m} \left[ \sum_ {x \in \left[ B _ {c} \cup B _ {l} \right]} \sum_ {k = 1} ^ {K} A _ {m k} ^ {x} \cdot W _ {m} ^ {\prime} x \left(p + \Delta p _ {m k} ^ {x}\right) \right], \tag {1} \\ \end{array} +$$ + +where $m$ denotes the attention head, $K$ denotes the number of sampled keys, and $p$ denotes reference points. We use $W_{m}$ and $W_{m}^{\prime}$ to represent the learnable projection matrixes. Note that in Eq. 1, the input feature $x$ could be either $B_{c}$ , $B_{l}$ , or both. It enables MetaBEV to flexibly utilize multimodal features for the deformable attention calculation during both training and testing. + +The cross-attention mechanism performs the fusion process layer by layer, enabling the meta-BEV to iteratively "evolve" into fused features that capture both semantic and geometric information from the cameras and LiDAR modalities, respectively. Note that we sequentially incorporate $N$ cross-modal attention layers to capture intercorrelations among the meta-BEV and diverse sensor features. Nonetheless, we have not yet explicitly modeled the intra-correlations, which refer to as the connection among different queries. Therefore, we introduce the self-attention layers to facilitate fused features capturing the intra-correlations. The details are discussed below. + +Self-Attention Layer. To construct the self-attention layer, we downgrade the modal-specific MLP into the unified MLP layer. Besides, to sufficiently model intra-correlations + +![](images/5cb87d87af221c5543b31a9abdf8fd382946bfaa7881bbc97681f2efde7f60f8.jpg) +Figure 4. Detailed illustration of a BEV-Evolving block. In the cross-modal deformable attention layer, We incorporate model-specific MLP layers to enable flexibly calculating sampling offsets and attention weights for an arbitrary modality. In FFN layer, we incorporate two MoE options to alleviate tasks conflict in multi-task learning. + +![](images/5adb55498d328fea61124a012018c1c6099309c3d80f9b1b6c1cb37cea1dda91.jpg) + +among queries, the input feature $x$ in Eq. 1 is substituted by $B_{m}$ , resulting in a self-attention calculation $\mathrm{DA}\mathrm{attn}(B_m,p,B_m)$ . We assemble only $M = 2$ self-attention layers in the BEV-Evolving Decoder, achieving a favorable trade-off between performance and computational efficiency. By modeling inter-modalities and intra-queries correlations, the fused BEV features are finally output for 3D predictions. It's experimentally found that the hybrid designs, combining both intra- and inter-correlations, provide comprehensive modeling on the fused BEV features, thus benefiting various tasks (as validated in Sec. 4.5). + +$\mathbf{M}^2\mathbf{o}\mathbf{E}$ Block. As shown in Fig. 4 I and II, following the previous setting of [28] that is designed for large language modeling via a mixture of experts layers (MoE), we incorporate the MLP layer in our BEV-Evolving block with MoE to introduce our $\mathbf{M}^2\mathbf{o}\mathbf{E}$ blocks for multi-task learning. We first illustrate the $\mathrm{RM}^2\mathrm{oE}$ (as shown in Fig. 4 I) with the following formulation, + +$$ +\mathrm {M} ^ {2} \mathrm {o E} (x) = \sum_ {i = 1} ^ {t} \mathcal {R} (x) _ {i} \mathcal {E} _ {i} (x), t \ll E \tag {2} +$$ + +where $x \in \mathbb{R}^D$ is the input tokens to the $\mathrm{RM}^2\mathrm{oE}$ -FFN layer, $\mathcal{R} : \mathbb{R}^D \to \mathbb{R}^E$ is a routing function which assigns each token to its belonging experts and $\mathcal{E}_i : \mathbb{R}^D \to \mathbb{R}^D$ is the token processing in expert $i$ . Both $\mathcal{E}_i$ and $\mathcal{R}$ are implemented by MLP layers, and $E$ is a hyper-parameter as the total expert capacity. With sparse $\mathcal{R}$ where top $t$ probability is selected, each token can only be routed to $t \ll E$ experts, while a lot of experts remain inactive. Under the extreme condition of $t = 1$ , the additional calculation only comes from $\mathcal{R}$ . For $\mathrm{HM}^2\mathrm{oE}$ , Fig. 4 II depicts a degenerate version when $E = \text{task number}$ and $\mathcal{R} = 1$ . In this scenario, tokens bypass the router allocation process and pass through the task-specific FFN networks before being merged by the task-fusion network. This super-linear scaling of the MLP layer facilitates multi-task training and inference by enabling the router to select appropriate experts. During network opti + +mization, such a process mitigates tasks conflict between 3D object detection and BEV map segmentation by separating the conflicting gradients (caused by diverse training objectives) with different experts. + +# 3.3. Sensor Failures + +A practical perception model is required to perform effectively even encountering corrupted or absent inputs. To this end, we define a series of sensor failures to simulate both sensor corruptions and complete sensor absence. For sensor corruptions, we include six types: 1) Limited Field of LiDAR (LF), which occurs when LiDAR data can only be collected from a portion of the field of view due to incorrect collection or partial hardware damage [40]; 2) Missing of Objects (MO), which appears when certain materials prevent some LiDAR points from being reflected [40]; 3) Beams Reduction (BR), occurring due to limited power supply or sensor processing capabilities; 4) View Drop (VD) and 5) View Noise (VN), resulting from camera faults; and 6) Obstacle Occlusion (OO), that is a real-world phenomenon where objects are occluded from the cameras. Furthermore, we evaluate MetaBEV using extreme sensor absence scenarios, including Missing Camera(MC) and Missing LiDAR(ML). As such, our evaluation takes into account both sensor corruptions and absence. + +# 3.4. Switched Modality Training + +The unique designs (i.e., modal-specific modules) in the BEV-Evolving block enable MetaBEV flexibly processing of either camera features, LiDAR features, or both. We propose a switched-modality training scheme to ensure precise predictions by using arbitrary modalities. This alternating strategy simulates real-world conditions during training, as MetaBEV randomly receives inputs from the aforementioned modalities with a predetermined probability. As a result, MetaBEV can conduct inferences on any input modality, thereby increasing its practicality in autonomous driv- + +
MethodsModalityMTLmAP(val)NDS(val)DrivablePed.CrossWalkwayStop LineCarparkDividerMean
M2BEV[36]CX41.747.077.2----40.5-
BEVFformer[21]CX41.651.780.1----25.7-
BEVFusion[25]CX35.641.281.754.858.447.450.746.456.6
X-Align[2]CX--82.455.659.349.653.847.458.0
MetaBEV-TCX49.449.783.356.761.450.855.548.059.3
MetaBEV-C55.560.4
PointPillars[16]LX52.361.372.043.153.129.727.737.543.8
CenterPoint[38]LX59.666.875.648.457.536.531.741.948.6
BEVFusion[25]LX64.769.375.648.457.536.431.741.948.6
MetaBEV-CLX62.568.687.963.471.655.055.155.764.8
MetaBEV-T64.269.3
PointPainting[31]L+CX65.869.675.948.557.136.934.541.949.1
MVP[39]L+CX66.170.076.148.757.036.933.042.249.0
TransFusion[1]L+CX67.371.2-------
BEVFusion[25]L+CX68.571.485.560.567.652.057.053.762.7
X-Align[2]L+CX--86.865.270.058.357.158.265.7
MetaBEV-TL+CX68.071.589.668.474.863.364.461.870.4
BEVFusion†[25]L+C✓-69.7------54.0
BEVFusion‡[25]L+C✓65.869.883.955.763.843.454.849.658.5
MetaBEV-MTL†L+C✓65.669.588.764.871.556.158.758.166.3
MetaBEV-MTL‡L+C✓65.469.888.564.971.856.761.158.266.9
+ +Table 1. Comparisons with SoTA methods on nuScenes val set. We use -C and -T to denote equipping MetaBEV with the CenterPoint head [38] and Transfusion head [1]. MTL stands for testing multi-tasks with the same model. † and ‡ stand for separating or sharing the BEV feature encoder, respectively. MetaBEV outperforms the SoTA multi-modal fusion methods by +4.7% mIOU on nuScenes(val) BEV map segmentation and achieves comparable 3D object detection performance. MetaBEV also performs best in multi-task learning. + +ing. Importantly, this approach requires only one set of pretrained weights for all the model's deployment. + +# 4. Experiments + +In this section, we detail the implementations and experimental settings on both sensor failures and tasks conflict. The performances on 3D detection and BEV map segmentation are presented to validate the effectiveness, flexibility, and robustness of our MetaBEV. + +# 4.1. Implementation Details + +Network Architectures. Swin-T [24] and VoxelNet [41] are adopted as feature encoders for the cameras and LiDAR, respectively. In the BEV-Evolving decoder, we employ four cross-modal attention layers and two self-attention layers to produce a fused BEV. We initialize the meta-BEV with a resolution of $180 \times 180$ to capture fine-grained correlations. Subsequently, we apply an FPN layer [23] to generate multi-scale features from the fused BEV. Unless specified otherwise, we use a Transformer head for 3D detection [1, 4, 34] and a CNN head [25] for map segmentation. + +Datasets and Evaluation Metrics. We evaluate MetaBEV on nuScenes [3], a large-scale multi-modal dataset for 3D detection and map segmentation. The dataset is split into 700/150/150 scenes for training/validation/testing. It contains data from multiple sensors, including six cameras, one + +LiDAR, and five radars. For camera inputs, each frame consists of six views of the surrounding environment at one specific timestamp. We resize the input views to $256 \times 704$ resolution and voxelize the point cloud to $0.075\mathrm{m}$ and $0.1\mathrm{m}$ for detection and segmentation, respectively. Our evaluation metrics align with [3]. For 3D detection, we utilize the standard nuScenes Detection Score (NDS) and mean Average Precision (mAP). For BEV map segmentation, we follow [25] to calculate the Mean Intersection over Union (mIoU) for map segmentation on the overall six categories. + +Training configurations. We follow the image and LiDAR data augmentation strategies from MMDetection3D [9] to enlarge the training samples' diversities. AdamW [26] is utilized with a weight decay of 0.05 and a cyclical learning rate schedule [30] for optimization. We take overall 26 training epochs for 3D detection, and 20 epochs for BEV map segmentation, with CBGS [42] to balance the data sampling. MetaBEV is trained on 8 A100 GPUs. For the switched-modality training, the training ratios for camera/LiDAR/both are uniformly set to be $1/3$ , $1/3$ , and $1/3$ , respectively. Further details are available in the appendix. + +# 4.2. Performance on full modalities + +We evaluate MetaBEV on 3D object detection and BEV map segmentation, utilizing either single or full modality inputs. Note that the BEV feature map size in MetaBEV is $180 \times 180$ , which is consistent with the BEV query utilized + +
MethodsCamera + LidarMissing CameraMissing LiDAR
mAPNDSmIoUmAPNDSmIoUmAPNDSmIoU
TransFusion [1]67.371.2-61.667.4----
BEVFusion [25]68.571.462.761.867.54.10.57.136.7
MetaBEV68.071.570.463.669.253.739.042.654.4
+ +Table 2. Experimental comparisons on extreme sensor missing. MetaBEV is able to totally drop the features from the missing modalities for inference, while others cannot. We attempt to replace the missing features with zero in other works so that they can output results, which are colored as blue. MetaBEV still consistently outperforms prior works when facing extreme sensor absence. + +
MethodsEvaluationLimited Field [-60,60]Missing Objects rate=1.0Beam Reduction 4 beamsView Drop 6 dropsView Noise 6 noiseObstacle Occlusion w occlusion
NDSmIoUNDSmIoUNDSmIoUNDSmIoUNDSmIoUNDSmIoU
BEVFusion [25]zero-shot41.647.262.161.858.355.367.54.166.925.868.645.8
MetaBEV47.061.262.569.257.764.368.343.568.045.270.061.2
BEVFusion [25]in-domain42.655.565.261.951.259.068.352.868.353.169.759.3
MetaBEV54.362.168.569.954.666.469.367.969.267.570.370.2
+ +Table 3. Experimental comparisons on sensor corruptions. Texts in blue denote the corruption degree. More detailed results are available in the appendix. MetaBEV consistently outperforms BEVFusion on various sensor corruptions in zero-shot and in-domain tests. + +in BEVFormer, thus being fairly compared. For 3D object detection, results in Tab. 1 show that MetaBEV achieves superior performance with the camera modality, and gets comparable performance to the state-of-the-art with both Li-DAR and multi-modalities. For example, with CenterPoint-3D [38], MetaBEV-C achieves an impressive $60.4\%$ NDS on nuScenes val set with camera inputs, for LiDAR and multi-modal inputs, MetaBEV gains $69.3\%$ and $71.5\%$ , respectively, which is comparable to several SoTA methods. We also notice that though MetaBEV exhibits a slightly lower mAP with full-modality inputs, it still achieves superior NDS with improved orientation estimation ( $27.2\%$ vs. $30.4\%$ mAOE) as well as distance evaluation ( $28.0\%$ vs. $28.7\%$ mATE) in such the case. Moreover, it is experimentally found that MetaBEV is effective in capturing fine-grained features for dense predictions, e.g., semantic prediction. For single-modality inputs, with only several MLP heads for prediction, MetaBEV achieves a $59.3\%$ mIoU on cameras, and an impressive $64.8\%$ mIoU on LiDAR $(+16.2\%)$ higher than BEVFusion [25]). Moreover, results in Tab. 1 show we set a new state-of-the-art (SOTA) performance of $70.4\%$ mIoU on BEV map segmentation, outperforming the previous best model [2] with $+4.7\%$ mIoU and the second-best method [25] by $+7.7\%$ mIoU. + +# 4.3. Performance on corruption + +We proceed to evaluate MetaBEV under various sensor failure cases, including complete sensor missing and various sensor corruptions. For the sensor missing, we train MetaBEV with the switched modality scheme, as described in Sec. 3.4. Previous fusion-based approaches, such as BEVFusion [25] and TransFusion [1], heavily rely on multi-modal features and cannot explicitly handle the ab + +sence of features caused by sensor missing. Nevertheless, we attempt to replace missing modalities with zero-initialized features for them, allowing the prior methods for predictions. Results in Tab. 2 show that MetaBEV demonstrates a stronger anti-corruption ability. Specifically, in case of missing LiDAR, MetaBEV improves $+35.5\%$ detection NDS and $+17.7\%$ segmentation mAP upon BEVFusion [25]; when encountering missing cameras, MetaBEV surpasses BEVFusion [25] by $+1.7\%$ NDS and $49.5\%$ mIoU. Notably, even when the cameras are missing, MetaBEV still achieves $53.7\%$ mIoU, surpassing the SoTA LiDAR-Only methods by $5.1\%$ (i.e., CenterPoint [38]) and $9.9\%$ (i.e., PointPillars [16]); and when the LiDAR is missing, MetaBEV even outperforms the camera-specific BEVFusion by $+1.4\%$ NDS $(42.6\%$ v.s. $41.2\%)$ . + +On the other hand, we conducted both zero-shot and in-domain tests on sensor corruptions. To evaluate the model's abilities in performing with unseen corrupted or missing data, we performed the zero-shot test by directly evaluating a trained model on such data. For the in-domain test, we train MetaBEV on corrupted data with random degrees, and then conduct evaluations on noise data with one specific degree. Tab.3 shows MetaBEV outperforms BEVFusion [25] on 11/12 corruptions on zero-shot evaluation. Moreover, when trained with randomly corrupted data, MetaBEV consistently outperformed BEVFusion. The results indicate that the fusion module, which is composed of CNNs (e.g., BEVFusion), has limited representational capabilities for corrupted data, while our approach leverages the attention mechanism for efficient modeling. + +
mAPNDSmIoU
Detection only67.671.0-
Segmentation only--70.4
H-MoER-MoE
XX64.869.464.7
✓X65.6 (+0.8)69.5 (+0.1)66.3 (+1.6)
X✓65.4 (+0.6)69.8 (+0.4)66.9 (+2.2)
+ +Table 4. We experiment on two kinds of MoE structures for Multi-Task Learning, and both show significant advantages. + +
Method#Params.(M)mAPNDS#Params.(M)mIoU
BEVFusion40.868.571.443.162.7
BEVFusion (Heavy)54.167.270.156.165.9
MetaBEV53.568.071.555.970.4
+ +Table 5. Comparisons on 3D detection and BEV-Map segmentation. + +# 4.4. Performance in Multi-Task Learning + +Tab. 4 presents the results of our multi-task learning (MTL) experiments for 3D object detection and BEV map segmentation. We begin with the framework designed for independent single-task learning with distinct task-specific heads and loaded a set of weights trained on multi-modal detection as pretrain. The model achieves $69.4\%$ NDS and $64.7\%$ mIoU for detection and segmentation, respectively, which is already a state-of-the-art performance. In light of this, we implement an MoE structure to help alleviate the gradient-conflict problem in MTL. Intuitively, we introduce a routing-based MoE structure, referred to as $\mathrm{RM}^2\mathrm{oE}$ , to replace the vanilla MLP layer. This implementation results in a remarkable improvement of $0.4\%$ NDS in detection and $2.2\%$ mIoU in segmentation. Considering the additional computation required by the routing mechanisms, we propose to further experiment on a simplified version $\mathrm{HM}^2\mathrm{oE}$ where the number of experts is adjusted to match that of the tasks, and the routing function is removed. We find it still achieves a notable improvement of $0.1\%$ NDS and $1.6\%$ mIoU. Upon the evaluation results, both implementations mitigate performance degradation in MTL to some extent. + +# 4.5. Ablation Studies + +Setup. We present the ablation studies for analyzing the network architectures and training schemes. All the ablation studies are performed on nuScenes validation set, with the training configurations set as default in Sec. 4.1. + +Network Configurations. We first explore the optimal architectures of the BEV-Evolving Decoder. Specifically, we analyze three components, including the combination of the layers, reference points number ( $p$ in Eq.1), and expert number ( $E$ in Eq.2). Our findings in Tab. 6a indicate that a few layers of cross-attention are sufficient to produce effec + +tive predictions while stacking more cross-attention layers does not necessarily enhance the model's capacities (68.3% and 68.2% NDS for 6 and 8 cross-attention layers, respectively). The same findings also suit the reference points number, where increasing the sampling points does not necessarily lead to better performance, as shown in Tab. 6b. On the contrary, we discovered that simply adding two layers of self-attention after the cross-attention layers significantly improve the prediction performance by +1.1% NDS in Tab. 6a. As mentioned in Sec. 3.2, the hybrid designs capture both intra- and inter-correlations simultaneously, resulting in complementary modeling. Moreover, in Tab. 6c, we discover that a larger model capacity (i.e., incorporating more experts) can effectively alleviate the performance drop in 3D detection and map segmentation. Specifically, MetaBEV equipped with 2/8 expert (i.e. activating the 2 experts with the highest scores from a total of 8 experts.) achieves the best performance compared to other configurations (66.9% mIoU and 69.8% NDS), while $\mathrm{HM}^2\mathrm{oE}$ is unaffected due to the fixed number of experts being equivalent to the number of tasks. + +Do More Parameters Guarantee Improved Model Accuracy? We note that incorporating deformable attention does introduce additional parameters to MetaBEV; however, this increment is minimal and acceptable (i.e., 54M v.s. 41M) in relation to its functional capabilities (addressing sensor failures). Besides, compared with BEVFusion, though MetaBEV achieves modest advancements on 3D detection (+0.1% NDS), the improvement on map segmentation is remarkably significant (+7.7% mIoU), which indicates the deformable attention facilitates more in per-pixel perception. To conduct a fair comparison, we consistently introduce more fusion layers to BEVFusion. Results in Tab. 5 demonstrate that increasing parameters of BEVFusion yields an improved performance in map segmentation, while a reduction in 3D detection accuracy. The decreased performance for 3D detection may be attributed to the challenging convergence for the larger parameters. Furthermore, it is observed that BEVFusion performs poorly in both 3D detection and map segmentation when compared to MetaBEV with the same parameter amount. This finding highlights the fact that having more model parameters does not guarantee improved model accuracy. + +Switched Modality Training. For the training strategy, using switched modality scheme to simulate the sensors missing, though simple, is the key to enabling MetaBEV with robust performance on completely sensor-failure scenarios. In Tab. 6d, comparing with the vanilla full-modality training approach, our proposed training strategy yields significant improvements on 3D detection by $+32.8\%$ NDS and $+1.0\%$ NDS, and improvements on map segmentation by $+17.9\%$ mIoU and $+16.7\%$ mIoU under LiDAR-missing + +
LayersmAP/NDS
4 cross61.7/67.0
6 cross63.0/68.3
8 cross62.5/68.2
2 self+4 cross64.2/69.3
+ +(a) The number of self/Cross-layer + +
PointsmAP/NDS
462.3/67.9
862.7/68.2
1262.3/68.0
1662.3/68.1
+ +(b) The number of reference points + +
ExpertsmAP/NDSmIoU
1/2 Expert65.8/69.863.3
1/4 Expert64.9/69.565.9
1/8 Expert65.4/69.766.4
2/8 Expert65.4/69.866.9
+ +(c) Expert number + +
TaskMetricsVanilla trainingSwitched Modality Training
Lidar-MissingCamera-MissingFullLidar-MissingCamera-MissingFull
3D detectionNDS9.868.271.042.6 (+32.8)69.2 (+1.0)71.5 (+0.5)
mAP2.962.467.439.0 (+36.1)63.6 (+1.2)68.0 (+0.6)
BEV-Map SegmentationmIoU36.527.070.454.4 (+17.9)53.7 (+16.7)68.5 (-1.9)
+ +(d) Evaluation of the NuScenes val dataset when Cameras or LiDAR totally fail. We test the performance with the switched modality training on both 3D detection and BEV-map segmentation tasks. +Table 6. Ablation studies for the model architectures and training strategy. Default settings are marked in gray in (a), (b), and (c). + +and camera-missing scenarios, respectively. More intriguingly, we find that the switched modality training could even enhance the model performance on full modalities, rising from $71.0\%$ NDS to $71.5\%$ NDS on 3D detection. + +# 5. Conclusion + +In this paper, we present a novel framework, named MetaBEV, for the purpose of solving sensor failures in the bird's-eye view (BEV) 3D detection and map segmentation. Our method integrates modal-specific layers into the cross-modal attention layer to enhance the fusion process, achieving appealing performance on full-modality inputs, and meanwhile MetaBEV effectively alleviates the significant performance degradation that is often caused by corrupted or missing sensor signals. We also introduce $\mathbf{M}^2\mathrm{oE}$ to handle potential conflicts between tasks. We hope that MetaBEV will provide a more focused and effective approach for investigating sensor-failure scenarios in the autonomous driving field. + +Limitations. Though we adopted the deformable attention [43] for efficiency, it unavoidably leads to a slight increase in network parameters compared to the lightweight solutions [25, 22]. Despite this, the benefits of mitigating sensor failures are highly desirable, and the additional computational overhead may be deemed acceptable. We acknowledge that lightweight networks could be an avenue for future research, potentially involving techniques such as network pruning, token reduction, etc. + +Acknowledgement. This paper is partially supported by the National Key R&D Program of China No.2022ZD0161000 and the General Research Fund of Hong Kong No.17200622. + +# References + +[1] Xuyang Bai, Zeyu Hu, Xinge Zhu, Qingqiu Huang, Yilun Chen, Hongbo Fu, and Chiew-Lan Tai. Transfusion: Robust lidar-camera fusion for 3d object detection with transformers. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. +[2] Shubhankar Borse, Marvin Klingner, Varun Ravi Kumar, Hong Cai, Abdulaziz Almuzairee, Senthil Yogamani, and Fatih Porikli. X-align: Cross-modal cross-view alignment for bird's-eye-view segmentation. In IEEE/CVF Winter Conference on Applications of Computer Vision, 2023. +[3] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. +[4] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In European Conference on Computer Vision, 2020. +[5] Runjian Chen, Yao Mu, Runsen Xu, Wenqi Shao, Chenhan Jiang, Hang Xu, Zhenguo Li, and Ping Luo. Co^3: Cooperative unsupervised 3d representation learning for autonomous driving. arXiv preprint arXiv:2206.04028, 2022. +[6] Xiaozhi Chen, Huimin Ma, Ji Wan, Bo Li, and Tian Xia. Multi-view 3d object detection network for autonomous driving. In Proceedings of the IEEE conference on Computer Vision and Pattern Recognition, 2017. +[7] Xuanyao Chen, Tianyuan Zhang, Yue Wang, Yilun Wang, and Hang Zhao. Futr3d: A unified sensor fusion framework for 3d detection. arXiv preprint arXiv:2203.10642, 2022. +[8] Aakanksha Chowdhery, Sharan Narang, Jacob Devlin, Maarten Bosma, Gaurav Mishra, Adam Roberts, Paul Barham, Hyung Won Chung, Charles Sutton, Sebastian Gehrmann, et al. Palm: Scaling language modeling with pathways. arXiv preprint arXiv:2204.02311, 2022. + +[9] MMDetection3D Contributors. MMDetection3D: OpenMMLab next-generation platform for general 3D object detection. https://github.com/open-mmlab/mmdetection3d, 2020. +[10] Danny Driess, Fei Xia, Mehdi SM Sajjadi, Corey Lynch, Aakanksha Chowdhery, Brian Ichter, Ayzaan Wahid, Jonathan Tompson, Quan Vuong, Tianhe Yu, et al. Palme: An embodied multimodal language model. arXiv preprint arXiv:2303.03378, 2023. +[11] Chongjian Ge, Youwei Liang, Yibing Song, Jianbo Jiao, Jue Wang, and Ping Luo. Revitalizing cnn attention via transformers in self-supervised visual representation learning. Advances in Neural Information Processing Systems, 2021. +[12] Chongjian Ge, Jiangliu Wang, Zhan Tong, Shoufa Chen, Yibing Song, and Ping Luo. Soft neighbors are positive supporters in contrastive visual representation learning. arXiv preprint arXiv:2303.17142, 2023. +[13] Yihan Hu, Jiazhi Yang, Li Chen, Keyu Li, Chonghao Sima, Xizhou Zhu, Siqi Chai, Senyao Du, Tianwei Lin, Henhai Wang, et al. Planning-oriented autonomous driving. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2023. +[14] Tengteng Huang, Zhe Liu, Xiwu Chen, and Xiang Bai. Epnet: Enhancing point features with image semantics for 3d object detection. In European Conference on Computer Vision, 2020. +[15] Sebastian Jasczur, Aakanksha Chowdhery, Afroz Mohiuddin, Lukasz Kaiser, Wojciech Gajewski, Henryk Michalewski, and Jonni Kanerva. Sparse is enough in scaling transformers. Advances in Neural Information Processing Systems, 2021. +[16] Alex H Lang, Sourabh Vora, Holger Caesar, Lubing Zhou, Jiong Yang, and Oscar Beijbom. Pointpillars: Fast encoders for object detection from point clouds. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. +[17] Dmitry Lepikhin, HyoukJoong Lee, Yuanzhong Xu, Dehao Chen, Orhan First, Yanping Huang, Maxim Krikun, Noam Shazeer, and Zhifeng Chen. Gshard: Scaling giant models with conditional computation and automatic sharding. International Conference on Learning Representations, 2020. +[18] Yanwei Li, Yilun Chen, Xiaojuan Qi, Zeming Li, Jian Sun, and Jiaya Jia. Unifying voxel-based representation with transformer for 3d object detection. arXiv preprint arXiv:2206.00630, 2022. +[19] Yingwei Li, Adams Wei Yu, Tianjian Meng, Ben Caine, Jiquan Ngiam, Daiyi Peng, Junyang Shen, Yifeng Lu, Denny Zhou, Quoc V Le, et al. Deepfusion: Lidar-camera deep fusion for multi-modal 3d object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. +[20] Yingwei Li, Adams Wei Yu, Tianjian Meng, Ben Caine, Ji-quan Ngiam, Daiyi Peng, Junyang Shen, Yifeng Lu, Denny Zhou, Quoc V Le, et al. Deepfusion: Lidar-camera deep fusion for multi-modal 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. +[21] Zhiqi Li, Wenhai Wang, Hongyang Li, Enze Xie, Chonghao Sima, Tong Lu, Yu Qiao, and Jifeng Dai. Bevformer: + +Learning bird's-eye-view representation from multi-camera images via spatiotemporal transformers. In European Conference on Computer Vision, 2022. +[22] Tingting Liang, Hongwei Xie, Kaicheng Yu, Zhongyu Xia, Zhiwei Lin, Yongtao Wang, Tao Tang, Bing Wang, and Zhi Tang. Bevfusion: A simple and robust lidar-camera fusion framework. arXiv preprint arXiv:2205.13790, 2022. +[23] Tsung-Yi Lin, Piotr Dólar, Ross Girshick, Kaiming He, Bharath Hariharan, and Serge Belongie. Feature pyramid networks for object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2017. +[24] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In IEEE/CVF International Conference on Computer Vision, 2021. +[25] Zhijian Liu, Haotian Tang, Alexander Amini, Xinyu Yang, Huizi Mao, Daniela Rus, and Song Han. Bevfusion: Multi-task multi-sensor fusion with unified bird's-eye view representation. arXiv preprint arXiv:2205.13542, 2022. +[26] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. arXiv preprint arXiv:1711.05101, 2017. +[27] Jonah Philion and Sanja Fidler. Lift, splat, shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3d. In European Conference on Computer Vision, 2020. +[28] Noam Shazeer, Azalia Mirhoseini, Krzysztof Maziarz, Andy Davis, Quoc Le, Geoffrey Hinton, and Jeff Dean. Outrageously large neural networks: The sparsely-gated mixture-of-experts layer. arXiv preprint arXiv:1701.06538, 2017. +[29] Vishwanath A Sindagi, Yin Zhou, and Oncel Tuzel. Mvxnet: Multimodal voxelnet for 3d object detection. In International Conference on Robotics and Automation, 2019. +[30] Leslie N Smith. Cyclical learning rates for training neural networks. In IEEE/CVF Winter Conference on Applications of Computer Vision, 2017. +[31] Sourabh Vora, Alex H Lang, Bassam Helou, and Oscar Beijbom. Pointpainting: Sequential fusion for 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. +[32] Chunwei Wang, Chao Ma, Ming Zhu, and Xiaokang Yang. Pointaugmenting: Cross-modal augmentation for 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. +[33] Xin Wang, Fisher Yu, Lisa Dunlap, Yi-An Ma, Ruth Wang, Azalia Mirhoseini, Trevor Darrell, and Joseph E Gonzalez. Deep mixture of experts via shallow embedding. In Uncertainty in artificial intelligence, pages 552-562, 2020. +[34] Yue Wang, Vitor Campagnolo Guizilini, Tianyuan Zhang, Yilun Wang, Hang Zhao, and Justin Solomon. Detr3d: 3d object detection from multi-view images via 3d-to-2d queries. In Conference on Robot Learning, 2022. +[35] Barret Zoph William Fedus and Noam Shazeer. Switch transformers: Scaling to trillion parameter models with simple and efficient sparsity. Computer Research Repository, 2021. +[36] Enze Xie, Zhiding Yu, Daquan Zhou, Jonah Philion, Anima Anandkumar, Sanja Fidler, Ping Luo, and Jose M Alvarez. M^2bev: Multi-camera joint 3d detection and segmentation + +with unified birds-eye view representation. arXiv preprint arXiv:2204.05088, 2022. +[37] Brandon Yang, Gabriel Bender, Quoc V Le, and Jiquan Ngiam. Condconv: Conditionally parameterized convolutions for efficient inference. Advances in Neural Information Processing Systems, 2019. +[38] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Center-based 3d object detection and tracking. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. +[39] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Multimodal virtual point 3d detection. Advances in Neural Information Processing Systems, 2021. +[40] Kaicheng Yu, Tang Tao, Hongwei Xie, Zhiwei Lin, Zhongwei Wu, Zhongyu Xia, Tingting Liang, Haiyang Sun, Jiong Deng, Dayang Hao, et al. Benchmarking the robustness of lidar-camera fusion for 3d object detection. arXiv preprint arXiv:2205.14951, 2022. +[41] Yin Zhou and Oncel Tuzel. Voxelnet: End-to-end learning for point cloud based 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2018. +[42] Benjin Zhu, Zhengkai Jiang, Xiangxin Zhou, Zeming Li, and Gang Yu. Class-balanced grouping and sampling for point cloud 3d object detection. arXiv preprint arXiv:1908.09492, 2019. +[43] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable detr: Deformable transformers for end-to-end object detection. arXiv preprint arXiv:2010.04159, 2020. \ No newline at end of file diff --git a/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/images.zip b/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..da8763cd6655d17cbf960ea5b1475fbe5493ca30 --- /dev/null +++ b/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:335bce27009f7dff35545dfdb169f40d7c2824dd8b1269e4161c69da0ba8e1e2 +size 603732 diff --git a/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/layout.json b/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..7552753b07ee633add39788c6f074426f34d171c --- /dev/null +++ b/2023/MetaBEV_ Solving Sensor Failures for 3D Detection and Map Segmentation/layout.json @@ -0,0 +1,8696 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 63, + 103, + 530, + 122 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 103, + 530, + 122 + ], + "spans": [ + { + "bbox": [ + 63, + 103, + 530, + 122 + ], + "type": "text", + "content": "MetaBEV: Solving Sensor Failures for 3D Detection and Map Segmentation" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 137, + 141, + 453, + 157 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 137, + 141, + 453, + 157 + ], + "spans": [ + { + "bbox": [ + 137, + 141, + 453, + 157 + ], + "type": "text", + "content": "Chongjian Ge" + }, + { + "bbox": [ + 137, + 141, + 453, + 157 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 137, + 141, + 453, + 157 + ], + "type": "text", + "content": " Junsong Chen" + }, + { + "bbox": [ + 137, + 141, + 453, + 157 + ], + "type": "inline_equation", + "content": "^{3,1*}" + }, + { + "bbox": [ + 137, + 141, + 453, + 157 + ], + "type": "text", + "content": " Enze Xie" + }, + { + "bbox": [ + 137, + 141, + 453, + 157 + ], + "type": "inline_equation", + "content": "^{2\\dagger}" + }, + { + "bbox": [ + 137, + 141, + 453, + 157 + ], + "type": "text", + "content": " Zhongdao Wang" + }, + { + "bbox": [ + 137, + 141, + 453, + 157 + ], + "type": "inline_equation", + "content": "^{2}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 156, + 157, + 436, + 172 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 156, + 157, + 436, + 172 + ], + "spans": [ + { + "bbox": [ + 156, + 157, + 436, + 172 + ], + "type": "text", + "content": "Lanqing Hong² Huchuan Lu³ Zhenguo Li² Ping Luo¹,⁴†" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 153, + 174, + 441, + 188 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 153, + 174, + 441, + 188 + ], + "spans": [ + { + "bbox": [ + 153, + 174, + 441, + 188 + ], + "type": "text", + "content": "1The University of Hong Kong 2Huawei Noah's Ark Lab" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 153, + 188, + 441, + 202 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 153, + 188, + 441, + 202 + ], + "spans": [ + { + "bbox": [ + 153, + 188, + 441, + 202 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 153, + 188, + 441, + 202 + ], + "type": "text", + "content": "Dalian University of Technology " + }, + { + "bbox": [ + 153, + 188, + 441, + 202 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 153, + 188, + 441, + 202 + ], + "type": "text", + "content": "Shanghai AI Laboratory" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 106, + 205, + 487, + 216 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 106, + 205, + 487, + 216 + ], + "spans": [ + { + "bbox": [ + 106, + 205, + 487, + 216 + ], + "type": "text", + "content": "rhettgee " + }, + { + "bbox": [ + 106, + 205, + 487, + 216 + ], + "type": "inline_equation", + "content": "@" + }, + { + "bbox": [ + 106, + 205, + 487, + 216 + ], + "type": "text", + "content": " connect.hku.hk jschen@mail.dlut.edu.cn lhchuan@dlut.edu.cn" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 99, + 218, + 495, + 230 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 99, + 218, + 495, + 230 + ], + "spans": [ + { + "bbox": [ + 99, + 218, + 495, + 230 + ], + "type": "text", + "content": "{xie.enze, wangzhongdao, honglanqing, li.zhenguo}@huawei.com pluo@cs.hku.hk" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 156, + 232, + 436, + 244 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 156, + 232, + 436, + 244 + ], + "spans": [ + { + "bbox": [ + 156, + 232, + 436, + 244 + ], + "type": "text", + "content": "Project page: https://chongjiange.github.io/metabev.html" + } + ] + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 50, + 251, + 545, + 415 + ], + "blocks": [ + { + "bbox": [ + 50, + 251, + 545, + 415 + ], + "lines": [ + { + "bbox": [ + 50, + 251, + 545, + 415 + ], + "spans": [ + { + "bbox": [ + 50, + 251, + 545, + 415 + ], + "type": "image", + "image_path": "d22cc19f55915b84edf7a6856dd242f5f43ce0741ea6e2f353a506f4b9bc47ff.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 430, + 546, + 474 + ], + "lines": [ + { + "bbox": [ + 46, + 430, + 546, + 474 + ], + "spans": [ + { + "bbox": [ + 46, + 430, + 546, + 474 + ], + "type": "text", + "content": "Figure 1. Selected 3D prediction results under various sensor failures. MetaBEV shows stronger robustness on both map segmentation and 3D detection compared to the representative multi-modal method, e.g., BEVFusion [25]. Notably, in case of an entire sensor absent (e.g., Camera or LiDAR), MetaBEV provides satisfactory outcomes while existing methods fail to. Top two rows: 3D prediction results. Bottom row: the corresponding ground truths." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 143, + 484, + 192, + 497 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 484, + 192, + 497 + ], + "spans": [ + { + "bbox": [ + 143, + 484, + 192, + 497 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 511, + 288, + 679 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 511, + 288, + 679 + ], + "spans": [ + { + "bbox": [ + 46, + 511, + 288, + 679 + ], + "type": "text", + "content": "Perception systems in modern autonomous driving vehicles typically take inputs from complementary multi-modal sensors, e.g., LiDAR and cameras. However, in real-world applications, sensor corruptions and failures lead to inferior performances, thus compromising autonomous safety. In this paper, we propose a robust framework, called MetaBEV, to address extreme real-world environments, involving overall six sensor corruptions and two extreme sensor-missing situations. In MetaBEV, signals from multiple sensors are first processed by modal-specific encoders. Subsequently, a set of dense BEV queries are initialized, termed meta-BEV. These queries are then processed iteratively by a BEV-Evolving decoder, which selectively aggregates deep features from either LiDAR, cameras, or both" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "spans": [ + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "text", + "content": "modalities. The updated BEV representations are further leveraged for multiple 3D prediction tasks. Additionally, we introduce a new " + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "inline_equation", + "content": "M^2 oE" + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "text", + "content": " structure to alleviate the performance drop on distinct tasks in multi-task joint learning. Finally, MetaBEV is evaluated on the nuScenes dataset with 3D object detection and BEV map segmentation tasks. Experiments show MetaBEV outperforms prior arts by a large margin on both full and corrupted modalities. For instance, when the LiDAR signal is missing, MetaBEV improves " + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "inline_equation", + "content": "35.5\\%" + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "text", + "content": " detection NDS and " + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "inline_equation", + "content": "17.7\\%" + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "text", + "content": " segmentation mIoU upon the vanilla BEVFusion [25] model; and when the camera signal is absent, MetaBEV still achieves " + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "inline_equation", + "content": "69.2\\%" + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "text", + "content": " NDS and " + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "inline_equation", + "content": "53.7\\%" + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "text", + "content": " mIoU, which is even higher than previous works that perform on full-modalities. Moreover, MetaBEV performs moderately against previous methods in both canonical perception and multi-task learning settings, refreshing state-of-the-art nuScenes BEV map segmentation with " + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "inline_equation", + "content": "70.4\\%" + }, + { + "bbox": [ + 306, + 485, + 546, + 689 + ], + "type": "text", + "content": " mIoU." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 57, + 693, + 132, + 703 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 693, + 132, + 703 + ], + "spans": [ + { + "bbox": [ + 57, + 693, + 132, + 703 + ], + "type": "inline_equation", + "content": "^{0}*" + }, + { + "bbox": [ + 57, + 693, + 132, + 703 + ], + "type": "text", + "content": " Equal contribution." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 59, + 703, + 145, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 703, + 145, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 703, + 145, + 712 + ], + "type": "inline_equation", + "content": "^{0}\\dagger" + }, + { + "bbox": [ + 59, + 703, + 145, + 712 + ], + "type": "text", + "content": " Corresponding authors." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "8721" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 71, + 128, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 71, + 128, + 84 + ], + "spans": [ + { + "bbox": [ + 47, + 71, + 128, + 84 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 91, + 287, + 258 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 91, + 287, + 258 + ], + "spans": [ + { + "bbox": [ + 46, + 91, + 287, + 258 + ], + "type": "text", + "content": "Perceiving the surrounding environment is a fundamental capability of autonomous driving systems. In pursuit of higher perceptual accuracy, prior works make significant efforts in designing stronger task-specific modules [41, 16, 21], cultivating effective training paradigms [5], leveraging multi-modalities [25, 22, 7], etc. Among all these, the multi-sensors fusion strategy exhibits significant advantages in achieving stronger perception abilities [31, 39, 25, 1], thus being widely explored in both academia and industry. While the majority of works focus on achieving optimal performance on ideal multi-modal inputs for a single specific task, they unintentionally neglect how the designed models perform with sensor failures, which are commonly encountered and inevitable in real-world applications." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 258, + 288, + 510 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 258, + 288, + 510 + ], + "spans": [ + { + "bbox": [ + 46, + 258, + 288, + 510 + ], + "type": "text", + "content": "To alleviate performance drop on sensor failures, previous works encounter two challenges as follows. 1) Features misalignment: Existing fusion methods typically utilize CNNs and features concatenation for fusion [25, 22]. The pixel-level position correlation is consistently imposed, giving rise to multi-modal features misalignment, especially when geometric-related noises are introduced. This issue could be attributed to the intrinsic characteristics of CNNs, which exhibit limitations in long-range perception and adaptive attention to input features. 2) Heavily reliant on complete modalities: Prior arts generate the fused BEV features using either query-indexing or channel-wise fusion manners. Query-indexing methods [29, 31, 32, 14] typically rely on LiDAR and 2D Camera features for mutual querying, while channel-wise fusion approaches [25, 22] are inevitable to involve element-wise operations (e.g. element-sum) for feature merging. Both fusion strategies are heavily dependent on complete modality inputs and lead to inferior perception performance encountering extreme sensor failures such as LiDAR-missing or Cameras-missing, thus being limited in the practical applications." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 510, + 287, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 510, + 287, + 665 + ], + "spans": [ + { + "bbox": [ + 46, + 510, + 287, + 665 + ], + "type": "text", + "content": "In this research, we propose MetaBEV to tackle the above features misalignment and full-modality dependence problems through modality-arbitrary and task-agnostic learning in the unified bird's-eye view (BEV) representation space [18]. We identify the major bottleneck in modality-dependent methods is the lack of designs that enable independent fusion of different modalities by the fusion module. Therefore, we present a modality-arbitrary BEV-Evolving decoder, which leverages cross-modal attention to correlate the learnable meta-BEV queries with either a single camera-BEV feature, LiDAR-BEV feature, or both to eliminate the bottleneck. Finally, we apply a few task-specific heads to support different 3D perception predictions." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 287, + 714 + ], + "type": "text", + "content": "Except for the canonical perception (on no corrupted sensors), we also evaluate MetaBEV on overall six sensor corruptions (Limited Field (LF), Beams Reduction (BR), Missing Objects (MO), View Drop (VD), View Noise (VN)," + } + ] + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 309, + 73, + 542, + 177 + ], + "blocks": [ + { + "bbox": [ + 309, + 73, + 542, + 177 + ], + "lines": [ + { + "bbox": [ + 309, + 73, + 542, + 177 + ], + "spans": [ + { + "bbox": [ + 309, + 73, + 542, + 177 + ], + "type": "image", + "image_path": "03880d9e863487a61412f4b354f6d57ee44cc5a52e7c41df2dbd8a9c9d1ca746.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 182, + 547, + 290 + ], + "lines": [ + { + "bbox": [ + 304, + 182, + 547, + 290 + ], + "spans": [ + { + "bbox": [ + 304, + 182, + 547, + 290 + ], + "type": "text", + "content": "Figure 2. MetaBEV shows stronger robustness on missing sensors. We perform representative methods with full/missing modalities on both map segmentation (the left part) and 3D detection (the right part). Results show MetaBEV can mitigate the performance drop on input absence. Quantitatively, when facing missing cameras, MetaBEV still achieves " + }, + { + "bbox": [ + 304, + 182, + 547, + 290 + ], + "type": "inline_equation", + "content": "53.7\\%" + }, + { + "bbox": [ + 304, + 182, + 547, + 290 + ], + "type": "text", + "content": " mIoU, which outperforms the representative method (i.e., BEVFusion [25]), by " + }, + { + "bbox": [ + 304, + 182, + 547, + 290 + ], + "type": "inline_equation", + "content": "+49.6\\%" + }, + { + "bbox": [ + 304, + 182, + 547, + 290 + ], + "type": "text", + "content": " mIoU, and is even better than MVP [39] performed on full-modalities. The superior performance could also be found on 3D detection tasks." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "spans": [ + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "text", + "content": "Obstacle Occlusion (OO)) and two sensor-missing scenarios (Missing LiDAR (ML) and Missing Camera (MC)). Compared with prior works, MetaBEV performs more robustly as depicted in Fig. 1. For example, it achieves " + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "inline_equation", + "content": "69.2\\%" + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "text", + "content": " NDS and " + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "inline_equation", + "content": "42.6\\%" + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "text", + "content": " NDS on detection when totally missing the cameras or LiDAR, respectively. For map segmentation, when total cameras absence occurs, MetaBEV could still achieve better performance compared to the work trained on multi-modalities (i.e., " + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "inline_equation", + "content": "54.7\\%" + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "text", + "content": " v.s. MVP's " + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "inline_equation", + "content": "49.0\\%" + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "text", + "content": " mIoU [39]). Besides, the attention-based MetaBEV exhibits inherent robustness against multiple heavy corruptions with zero-shot and in-domain tests. For instance, as shown in Tab. 3, even missing " + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "inline_equation", + "content": "66.6\\%" + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "text", + "content": " of LiDAR points, MetaBEV still achieves " + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "inline_equation", + "content": "55\\%" + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "text", + "content": " NDS, outperforming the competitor by " + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "inline_equation", + "content": "+11.7\\%" + }, + { + "bbox": [ + 304, + 320, + 545, + 488 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 488, + 545, + 619 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 488, + 545, + 619 + ], + "spans": [ + { + "bbox": [ + 304, + 488, + 545, + 619 + ], + "type": "text", + "content": "Moreover, considering the limited computational resource in practice, using a single framework with shared parameters for different tasks is more efficient than using separate frameworks for multiple tasks. However, the task conflicts in the joint learning of detection and segmentation often lead to severe performance drop [36, 21, 25], and existing methods rarely analyze and design for multi-task learning (MTL). We incorporate MetaBEV with a flexible module based on Multi-Task Mixture of Experts " + }, + { + "bbox": [ + 304, + 488, + 545, + 619 + ], + "type": "inline_equation", + "content": "(\\mathbf{M}^2\\mathrm{oE})" + }, + { + "bbox": [ + 304, + 488, + 545, + 619 + ], + "type": "text", + "content": " to demonstrate one possible solution for MTL and hope to stimulate further research in this area." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 317, + 620, + 539, + 632 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 620, + 539, + 632 + ], + "spans": [ + { + "bbox": [ + 317, + 620, + 539, + 632 + ], + "type": "text", + "content": "The appealing advantages of MetaBEV are concluded:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 314, + 641, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 314, + 641, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 314, + 641, + 545, + 713 + ], + "type": "text", + "content": "1. MetaBEV is a novel BEV perception framework for 3D object detection and BEV map segmentation, which can maintain resilient performance under arbitrary sensor input. Plenty of real-world sensor corruptions are formulated as well as methodically experimented with and analyzed to verify its robustness." + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8722" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 54, + 71, + 286, + 164 + ], + "type": "list", + "angle": 0, + "index": 2, + "blocks": [ + { + "bbox": [ + 54, + 71, + 286, + 107 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 71, + 286, + 107 + ], + "spans": [ + { + "bbox": [ + 54, + 71, + 286, + 107 + ], + "type": "text", + "content": "2. MetaBEV involves the " + }, + { + "bbox": [ + 54, + 71, + 286, + 107 + ], + "type": "inline_equation", + "content": "\\mathbf{M}^2\\mathrm{oE}" + }, + { + "bbox": [ + 54, + 71, + 286, + 107 + ], + "type": "text", + "content": " structures to alleviate tasks conflict when performing 3D detection and segmentation tasks with the same trained weights." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 54, + 118, + 286, + 164 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 118, + 286, + 164 + ], + "spans": [ + { + "bbox": [ + 54, + 118, + 286, + 164 + ], + "type": "text", + "content": "3. MetaBEV achieves state-of-the-art performance on nuScenes dataset [3]. It's the first method designed for both sensor failures and tasks conflict. We hope MetaBEV will facilitate future research." + } + ] + } + ], + "index": 1 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 47, + 177, + 133, + 189 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 177, + 133, + 189 + ], + "spans": [ + { + "bbox": [ + 47, + 177, + 133, + 189 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 197, + 179, + 209 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 197, + 179, + 209 + ], + "spans": [ + { + "bbox": [ + 47, + 197, + 179, + 209 + ], + "type": "text", + "content": "2.1. LiDAR-Camera Fusion" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 216, + 286, + 407 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 216, + 286, + 407 + ], + "spans": [ + { + "bbox": [ + 47, + 216, + 286, + 407 + ], + "type": "text", + "content": "In 3D perception tasks, the effectiveness of multi-sensor fusion is notable. Therefore, researchers have focused on better combining geometric-centric point clouds and semantic-centric images. Existing methods mainly focus on three aspects: proposal-level [6], point-level [7, 1, 19], and feature-level [25, 22]. While attempting to combine multiple modalities, existing approaches typically adopt similar fusion strategies, including query-indexing fusion [1] and channel-wise fusion [25, 22]. Though showing effective in full-modality input, the above fusion manners usually associate multi-modal features tightly among points or pixels, causing features in these methods to be susceptible to spatial misalignment issues and suffering from system collapses due to sensor missing. In our work, we explore an approach that can handle arbitrary modality freely to mitigate the above limitations." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 416, + 195, + 428 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 416, + 195, + 428 + ], + "spans": [ + { + "bbox": [ + 47, + 416, + 195, + 428 + ], + "type": "text", + "content": "2.2. Sensors-Failure Perception" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 435, + 286, + 614 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 435, + 286, + 614 + ], + "spans": [ + { + "bbox": [ + 47, + 435, + 286, + 614 + ], + "type": "text", + "content": "Sensor failures can significantly impact the accuracy of 3D perception, thereby jeopardizing the safety of autonomous driving. Therefore, conducting research on sensor failures is of utmost practical importance. Prior arts have made preliminary attempts to propose robust frameworks that address specific sensor failure scenarios on a case-by-case basis. These scenarios include camera-views drop [1], changes in illumination conditions [25, 7, 1], noisy inputs [20], and etc. More recently, [40] provided a comprehensive benchmark for verifying the robustness of methods mainly on sensor degradation. While previous works mainly focus on sensor corruptions, sensor absence is rarely noticed. In this work, we propose a novel perception framework that analyzes not only the aspects of sensor corruptions but also sensor absence comprehensively." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 623, + 167, + 635 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 623, + 167, + 635 + ], + "spans": [ + { + "bbox": [ + 47, + 623, + 167, + 635 + ], + "type": "text", + "content": "2.3. Multi-Task Learning" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 642, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 642, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 47, + 642, + 286, + 712 + ], + "type": "text", + "content": "Multi-task learning denotes performing multiple task predictions with one set of trained weights, which appeals to the research community for its practical values, such as the complementary performance, less computational cost, etc. However, multi-task learning can also be challenging, as the model must learn to balance various objectives of" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 72, + 545, + 335 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 335 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 335 + ], + "type": "text", + "content": "each task and avoid tasks conflict. In 3D perception, the tasks conflict has been proven by " + }, + { + "bbox": [ + 304, + 72, + 545, + 335 + ], + "type": "inline_equation", + "content": "\\mathbf{M}^2\\mathrm{BEV}" + }, + { + "bbox": [ + 304, + 72, + 545, + 335 + ], + "type": "text", + "content": " [36] and BEVFormer [21], which both perform joint training on camera-only 3D object detection and BEV map segmentation. It is empirically found that joint training leads to severe accuracy degradation on each single task. Prior arts do not address the issues effectively due to their unified models and usually solve the problems from the learning perspective. For example, UniAD [13] adopts multiple training stages to adjust the overall network module by module to avoid gradient conflicts in multi-task learning, which is not end-to-end and can not be optimized layer-by-layer to adjust gradients. Inspired by Mixture-of-Expert (MoE), which is specially designed for large language model in the Natural Language Processing [35, 17, 15, 37, 33] and self-supervised field [8, 11, 12, 10], we introduce a robust fusion module with a new " + }, + { + "bbox": [ + 304, + 72, + 545, + 335 + ], + "type": "inline_equation", + "content": "\\mathbf{M}^2\\mathrm{oE}" + }, + { + "bbox": [ + 304, + 72, + 545, + 335 + ], + "type": "text", + "content": "-FFN layer. The main purpose is to mitigate the gradient conflict between detection and segmentation to achieve a more balanced performance. MetaBEV is the first framework introducing MoE into 3D object detection and BEV map segmentation as a multi-modal, multitask, and robust approach." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 345, + 415, + 357 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 345, + 415, + 357 + ], + "spans": [ + { + "bbox": [ + 306, + 345, + 415, + 357 + ], + "type": "text", + "content": "3. MetaBEV Method" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 365, + 545, + 497 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 365, + 545, + 497 + ], + "spans": [ + { + "bbox": [ + 304, + 365, + 545, + 497 + ], + "type": "text", + "content": "We introduce a new baseline, which targets solving a range of sensor failures on 3D object detection and BEV map segmentation tasks. As opposed to existing perception methods that heavily rely on the complete sensor inputs, we connect different modalities through a parameterized metaBEV query and perform cross-modal attention to integrate both semantic and geometry representations from cameras and LiDAR. As shown in Figure 3, the overall pipeline consists of a multi-modalities feature encoder, a BEV-Evolving decoder with cross-modal deformable attention, and task-specific heads. Architecture designs are detailed as follows." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 504, + 479, + 515 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 504, + 479, + 515 + ], + "spans": [ + { + "bbox": [ + 306, + 504, + 479, + 515 + ], + "type": "text", + "content": "3.1. BEV Feature Encoder Overview" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 522, + 545, + 617 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 522, + 545, + 617 + ], + "spans": [ + { + "bbox": [ + 304, + 522, + 545, + 617 + ], + "type": "text", + "content": "MetaBEV generates fused features in the BEV space, as BEV representation provides a solution to combine image features with insufficient geometric knowledge and Li-DAR features lacking semantic understanding in a unified domain, allowing for complementary fusion. Additionally, the regularity of the BEV feature facilitates the effective integration of various advanced task heads, which could benefit plenty of perception tasks." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": "Camera/LiDAR to BEV. We build our multi-modal feature encoder based on the state-of-the-art perception method BEVFusion [25], which takes multi-view-images and LiDAR-points pair as input and transforms the camera features into BEV space with depth prediction and geometric projection, respectively. Specifically, we adopt a camera backbone " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\phi_c(\\cdot)" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": " to generate " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": "-view 2D image representations " + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "inline_equation", + "content": "F_{c}^{i}, i \\in [1,2,\\dots ,N]" + }, + { + "bbox": [ + 304, + 617, + 545, + 713 + ], + "type": "text", + "content": ". Then, following LSS [27], we" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 749, + 315, + 757 + ], + "type": "text", + "content": "8723" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 61, + 71, + 534, + 198 + ], + "blocks": [ + { + "bbox": [ + 61, + 71, + 534, + 198 + ], + "lines": [ + { + "bbox": [ + 61, + 71, + 534, + 198 + ], + "spans": [ + { + "bbox": [ + 61, + 71, + 534, + 198 + ], + "type": "image", + "image_path": "9fc992a5b13f3c12e2bb80e36fe0b5af602b4905e0ab32f6a1225262e4717f6a.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 201, + 547, + 246 + ], + "lines": [ + { + "bbox": [ + 46, + 201, + 547, + 246 + ], + "spans": [ + { + "bbox": [ + 46, + 201, + 547, + 246 + ], + "type": "text", + "content": "Figure 3. An overview of MetaBEV framework. The multi-modal inputs are separately processed by the camera encoder " + }, + { + "bbox": [ + 46, + 201, + 547, + 246 + ], + "type": "inline_equation", + "content": "\\phi_c(\\cdot)" + }, + { + "bbox": [ + 46, + 201, + 547, + 246 + ], + "type": "text", + "content": " and LiDAR encoder " + }, + { + "bbox": [ + 46, + 201, + 547, + 246 + ], + "type": "inline_equation", + "content": "\\phi_l(\\cdot)" + }, + { + "bbox": [ + 46, + 201, + 547, + 246 + ], + "type": "text", + "content": " to produce the BEV representations " + }, + { + "bbox": [ + 46, + 201, + 547, + 246 + ], + "type": "inline_equation", + "content": "B_{c}, B_{l}" + }, + { + "bbox": [ + 46, + 201, + 547, + 246 + ], + "type": "text", + "content": ". To generate the fused BEV features, a BEV-Evolving decoder takes multi-modal BEV representations and an externally initialized meta-BEV feature (as a query feature) for correlation computation. Task-specific heads take the fused features for 3D detection." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "spans": [ + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "text", + "content": "scatter the dense feature " + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "inline_equation", + "content": "F_{c}^{i}" + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "text", + "content": " into discrete 3D space and compress the generated 3D voxel features " + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "inline_equation", + "content": "V_{c} \\in \\mathbb{R}^{D \\times C \\times X \\times Y}" + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "text", + "content": " into the camera BEV representations " + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "inline_equation", + "content": "B_{c} \\in \\mathbb{R}^{C \\times X \\times Y}" + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "text", + "content": " with the pillar format [25], where " + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "inline_equation", + "content": "D, C, (X, Y)" + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "text", + "content": " denote the depth, dimension and spatial resolution of BEV feature, respectively. As for the LiDAR points, voxelization and sparse 3D convolutions " + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "inline_equation", + "content": "\\phi_{l}(\\cdot)" + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "text", + "content": " are utilized for encoding LiDAR BEV representation " + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "inline_equation", + "content": "B_{l}" + }, + { + "bbox": [ + 46, + 265, + 287, + 361 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 361, + 288, + 491 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 361, + 288, + 491 + ], + "spans": [ + { + "bbox": [ + 46, + 361, + 288, + 491 + ], + "type": "text", + "content": "Subsequently, Previous works [25, 22] usually involve concatenating and CNN-based feature fusion, which may cause significant performance drop under sensor corruptions or even system collapse when sensor failures occur. As mentioned in Sec. 1, CNNs exhibit limited effectiveness in large-corruption of input modality (due to the local-aggregation characteristic) and are inappropriate to deal with the absent input modality caused by sensor missing (due to the weight-sharing modeling). We solve the above challenges by introducing BEV-Evolving Decoder as follows." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 502, + 178, + 514 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 502, + 178, + 514 + ], + "spans": [ + { + "bbox": [ + 47, + 502, + 178, + 514 + ], + "type": "text", + "content": "3.2. BEV-Evolving Decoder" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": "The BEV-Evolving decoder consists of three key components: the cross-modal attention layers, the self-attention layers, and the plug-and-play " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{M}^2\\mathrm{oE}" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " blocks. The above two components facilitate fusing arbitrary modalities, while the " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{M}^2\\mathrm{oE}" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " blocks are designed for mitigating the tasks conflict. Cross-Modal Attention Layer. We first initialize a set of dense BEV queries, each representing the feature within a specific spatial grid, termed meta-BEV " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "(B_{m})" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": ". " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "B_{m}" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " is added with position embeddings (PE) and then correlates with either a camera BEV feature " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "(B_{c})" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": ", LiDAR BEV feature " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "(B_{l})" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " or both. To improve the computational efficiency, we adopt deformable attention " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathrm{DAttn}(\\cdot)" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " [43]. However, the original implementation " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathrm{DAttn}(\\cdot)" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " is not suitable for processing arbitrary inputs, as it utilizes one unified MLP layer to sample reference points " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\Delta p" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " and attention weights " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "A" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": ". We then introduce model-specific MLP layers (i.e., C-MLP for cameras" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "spans": [ + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "text", + "content": "and L-MLP for LiDAR in Fig. 4 III) for the flexibility of fusion. Given any input BEV representations " + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "inline_equation", + "content": "x \\in [B_c, B_l]" + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "text", + "content": " as value features, we first generate model-specific sampling offsets " + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "inline_equation", + "content": "\\Delta p^x" + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "text", + "content": " and attention weights " + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "inline_equation", + "content": "A^x" + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "text", + "content": " from query " + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "inline_equation", + "content": "B_m" + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "text", + "content": ". We then combine the pixel coordinates of " + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "inline_equation", + "content": "B_m" + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "text", + "content": " and the corresponding offsets " + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "inline_equation", + "content": "\\Delta p^x" + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "text", + "content": " to locate the sampled value features. After re-scaling the sampled features by the attention weights " + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "inline_equation", + "content": "A^x" + }, + { + "bbox": [ + 304, + 265, + 547, + 373 + ], + "type": "text", + "content": ", meta-BEV is updated from informative sensor features. The overall process is formulated in the following," + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 388, + 545, + 438 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 388, + 545, + 438 + ], + "spans": [ + { + "bbox": [ + 317, + 388, + 545, + 438 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathrm {D A t t n} \\left(B _ {m}, p, x\\right) = \\\\ \\sum_ {m = 1} ^ {M} W _ {m} \\left[ \\sum_ {x \\in \\left[ B _ {c} \\cup B _ {l} \\right]} \\sum_ {k = 1} ^ {K} A _ {m k} ^ {x} \\cdot W _ {m} ^ {\\prime} x \\left(p + \\Delta p _ {m k} ^ {x}\\right) \\right], \\tag {1} \\\\ \\end{array}", + "image_path": "7ab5038858a7b68732348db33f5bbfcea403d9ee056d261972bc675b53568da5.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "spans": [ + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "inline_equation", + "content": "m" + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "text", + "content": " denotes the attention head, " + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "text", + "content": " denotes the number of sampled keys, and " + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "text", + "content": " denotes reference points. We use " + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "inline_equation", + "content": "W_{m}" + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "inline_equation", + "content": "W_{m}^{\\prime}" + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "text", + "content": " to represent the learnable projection matrixes. Note that in Eq. 1, the input feature " + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "text", + "content": " could be either " + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "inline_equation", + "content": "B_{c}" + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "inline_equation", + "content": "B_{l}" + }, + { + "bbox": [ + 304, + 449, + 545, + 533 + ], + "type": "text", + "content": ", or both. It enables MetaBEV to flexibly utilize multimodal features for the deformable attention calculation during both training and testing." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 533, + 545, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 545, + 676 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 545, + 676 + ], + "type": "text", + "content": "The cross-attention mechanism performs the fusion process layer by layer, enabling the meta-BEV to iteratively \"evolve\" into fused features that capture both semantic and geometric information from the cameras and LiDAR modalities, respectively. Note that we sequentially incorporate " + }, + { + "bbox": [ + 304, + 533, + 545, + 676 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 304, + 533, + 545, + 676 + ], + "type": "text", + "content": " cross-modal attention layers to capture intercorrelations among the meta-BEV and diverse sensor features. Nonetheless, we have not yet explicitly modeled the intra-correlations, which refer to as the connection among different queries. Therefore, we introduce the self-attention layers to facilitate fused features capturing the intra-correlations. The details are discussed below." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 545, + 713 + ], + "type": "text", + "content": "Self-Attention Layer. To construct the self-attention layer, we downgrade the modal-specific MLP into the unified MLP layer. Besides, to sufficiently model intra-correlations" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "8724" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 71, + 302, + 200 + ], + "blocks": [ + { + "bbox": [ + 53, + 71, + 302, + 200 + ], + "lines": [ + { + "bbox": [ + 53, + 71, + 302, + 200 + ], + "spans": [ + { + "bbox": [ + 53, + 71, + 302, + 200 + ], + "type": "image", + "image_path": "5cb87d87af221c5543b31a9abdf8fd382946bfaa7881bbc97681f2efde7f60f8.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 201, + 547, + 236 + ], + "lines": [ + { + "bbox": [ + 46, + 201, + 547, + 236 + ], + "spans": [ + { + "bbox": [ + 46, + 201, + 547, + 236 + ], + "type": "text", + "content": "Figure 4. Detailed illustration of a BEV-Evolving block. In the cross-modal deformable attention layer, We incorporate model-specific MLP layers to enable flexibly calculating sampling offsets and attention weights for an arbitrary modality. In FFN layer, we incorporate two MoE options to alleviate tasks conflict in multi-task learning." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 303, + 72, + 539, + 200 + ], + "blocks": [ + { + "bbox": [ + 303, + 72, + 539, + 200 + ], + "lines": [ + { + "bbox": [ + 303, + 72, + 539, + 200 + ], + "spans": [ + { + "bbox": [ + 303, + 72, + 539, + 200 + ], + "type": "image", + "image_path": "5adb55498d328fea61124a012018c1c6099309c3d80f9b1b6c1cb37cea1dda91.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 265, + 286, + 395 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 265, + 286, + 395 + ], + "spans": [ + { + "bbox": [ + 46, + 265, + 286, + 395 + ], + "type": "text", + "content": "among queries, the input feature " + }, + { + "bbox": [ + 46, + 265, + 286, + 395 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 46, + 265, + 286, + 395 + ], + "type": "text", + "content": " in Eq. 1 is substituted by " + }, + { + "bbox": [ + 46, + 265, + 286, + 395 + ], + "type": "inline_equation", + "content": "B_{m}" + }, + { + "bbox": [ + 46, + 265, + 286, + 395 + ], + "type": "text", + "content": ", resulting in a self-attention calculation " + }, + { + "bbox": [ + 46, + 265, + 286, + 395 + ], + "type": "inline_equation", + "content": "\\mathrm{DA}\\mathrm{attn}(B_m,p,B_m)" + }, + { + "bbox": [ + 46, + 265, + 286, + 395 + ], + "type": "text", + "content": ". We assemble only " + }, + { + "bbox": [ + 46, + 265, + 286, + 395 + ], + "type": "inline_equation", + "content": "M = 2" + }, + { + "bbox": [ + 46, + 265, + 286, + 395 + ], + "type": "text", + "content": " self-attention layers in the BEV-Evolving Decoder, achieving a favorable trade-off between performance and computational efficiency. By modeling inter-modalities and intra-queries correlations, the fused BEV features are finally output for 3D predictions. It's experimentally found that the hybrid designs, combining both intra- and inter-correlations, provide comprehensive modeling on the fused BEV features, thus benefiting various tasks (as validated in Sec. 4.5)." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 396, + 286, + 479 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 396, + 286, + 479 + ], + "spans": [ + { + "bbox": [ + 46, + 396, + 286, + 479 + ], + "type": "inline_equation", + "content": "\\mathbf{M}^2\\mathbf{o}\\mathbf{E}" + }, + { + "bbox": [ + 46, + 396, + 286, + 479 + ], + "type": "text", + "content": " Block. As shown in Fig. 4 I and II, following the previous setting of [28] that is designed for large language modeling via a mixture of experts layers (MoE), we incorporate the MLP layer in our BEV-Evolving block with MoE to introduce our " + }, + { + "bbox": [ + 46, + 396, + 286, + 479 + ], + "type": "inline_equation", + "content": "\\mathbf{M}^2\\mathbf{o}\\mathbf{E}" + }, + { + "bbox": [ + 46, + 396, + 286, + 479 + ], + "type": "text", + "content": " blocks for multi-task learning. We first illustrate the " + }, + { + "bbox": [ + 46, + 396, + 286, + 479 + ], + "type": "inline_equation", + "content": "\\mathrm{RM}^2\\mathrm{oE}" + }, + { + "bbox": [ + 46, + 396, + 286, + 479 + ], + "type": "text", + "content": " (as shown in Fig. 4 I) with the following formulation," + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 91, + 487, + 287, + 518 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 487, + 287, + 518 + ], + "spans": [ + { + "bbox": [ + 91, + 487, + 287, + 518 + ], + "type": "interline_equation", + "content": "\\mathrm {M} ^ {2} \\mathrm {o E} (x) = \\sum_ {i = 1} ^ {t} \\mathcal {R} (x) _ {i} \\mathcal {E} _ {i} (x), t \\ll E \\tag {2}", + "image_path": "7032d59c23e1d0b58fcec381b70cededbc394f2eb9759c5887bc6be120baf53c.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "x \\in \\mathbb{R}^D" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " is the input tokens to the " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathrm{RM}^2\\mathrm{oE}" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": "-FFN layer, " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{R} : \\mathbb{R}^D \\to \\mathbb{R}^E" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " is a routing function which assigns each token to its belonging experts and " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{E}_i : \\mathbb{R}^D \\to \\mathbb{R}^D" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " is the token processing in expert " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": ". Both " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{E}_i" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{R}" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " are implemented by MLP layers, and " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "E" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " is a hyper-parameter as the total expert capacity. With sparse " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{R}" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " where top " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " probability is selected, each token can only be routed to " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "t \\ll E" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " experts, while a lot of experts remain inactive. Under the extreme condition of " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "t = 1" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": ", the additional calculation only comes from " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{R}" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": ". For " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathrm{HM}^2\\mathrm{oE}" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": ", Fig. 4 II depicts a degenerate version when " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "E = \\text{task number}" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{R} = 1" + }, + { + "bbox": [ + 46, + 521, + 287, + 713 + ], + "type": "text", + "content": ". In this scenario, tokens bypass the router allocation process and pass through the task-specific FFN networks before being merged by the task-fusion network. This super-linear scaling of the MLP layer facilitates multi-task training and inference by enabling the router to select appropriate experts. During network opti" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 265, + 545, + 313 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 265, + 545, + 313 + ], + "spans": [ + { + "bbox": [ + 304, + 265, + 545, + 313 + ], + "type": "text", + "content": "mization, such a process mitigates tasks conflict between 3D object detection and BEV map segmentation by separating the conflicting gradients (caused by diverse training objectives) with different experts." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 321, + 400, + 332 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 321, + 400, + 332 + ], + "spans": [ + { + "bbox": [ + 306, + 321, + 400, + 332 + ], + "type": "text", + "content": "3.3. Sensor Failures" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 339, + 545, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 339, + 545, + 567 + ], + "spans": [ + { + "bbox": [ + 304, + 339, + 545, + 567 + ], + "type": "text", + "content": "A practical perception model is required to perform effectively even encountering corrupted or absent inputs. To this end, we define a series of sensor failures to simulate both sensor corruptions and complete sensor absence. For sensor corruptions, we include six types: 1) Limited Field of LiDAR (LF), which occurs when LiDAR data can only be collected from a portion of the field of view due to incorrect collection or partial hardware damage [40]; 2) Missing of Objects (MO), which appears when certain materials prevent some LiDAR points from being reflected [40]; 3) Beams Reduction (BR), occurring due to limited power supply or sensor processing capabilities; 4) View Drop (VD) and 5) View Noise (VN), resulting from camera faults; and 6) Obstacle Occlusion (OO), that is a real-world phenomenon where objects are occluded from the cameras. Furthermore, we evaluate MetaBEV using extreme sensor absence scenarios, including Missing Camera(MC) and Missing LiDAR(ML). As such, our evaluation takes into account both sensor corruptions and absence." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 575, + 460, + 588 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 575, + 460, + 588 + ], + "spans": [ + { + "bbox": [ + 306, + 575, + 460, + 588 + ], + "type": "text", + "content": "3.4. Switched Modality Training" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "text", + "content": "The unique designs (i.e., modal-specific modules) in the BEV-Evolving block enable MetaBEV flexibly processing of either camera features, LiDAR features, or both. We propose a switched-modality training scheme to ensure precise predictions by using arbitrary modalities. This alternating strategy simulates real-world conditions during training, as MetaBEV randomly receives inputs from the aforementioned modalities with a predetermined probability. As a result, MetaBEV can conduct inferences on any input modality, thereby increasing its practicality in autonomous driv-" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8725" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 72, + 544, + 317 + ], + "blocks": [ + { + "bbox": [ + 50, + 72, + 544, + 317 + ], + "lines": [ + { + "bbox": [ + 50, + 72, + 544, + 317 + ], + "spans": [ + { + "bbox": [ + 50, + 72, + 544, + 317 + ], + "type": "table", + "html": "
MethodsModalityMTLmAP(val)NDS(val)DrivablePed.CrossWalkwayStop LineCarparkDividerMean
M2BEV[36]CX41.747.077.2----40.5-
BEVFformer[21]CX41.651.780.1----25.7-
BEVFusion[25]CX35.641.281.754.858.447.450.746.456.6
X-Align[2]CX--82.455.659.349.653.847.458.0
MetaBEV-TCX49.449.783.356.761.450.855.548.059.3
MetaBEV-C55.560.4
PointPillars[16]LX52.361.372.043.153.129.727.737.543.8
CenterPoint[38]LX59.666.875.648.457.536.531.741.948.6
BEVFusion[25]LX64.769.375.648.457.536.431.741.948.6
MetaBEV-CLX62.568.687.963.471.655.055.155.764.8
MetaBEV-T64.269.3
PointPainting[31]L+CX65.869.675.948.557.136.934.541.949.1
MVP[39]L+CX66.170.076.148.757.036.933.042.249.0
TransFusion[1]L+CX67.371.2-------
BEVFusion[25]L+CX68.571.485.560.567.652.057.053.762.7
X-Align[2]L+CX--86.865.270.058.357.158.265.7
MetaBEV-TL+CX68.071.589.668.474.863.364.461.870.4
BEVFusion†[25]L+C✓-69.7------54.0
BEVFusion‡[25]L+C✓65.869.883.955.763.843.454.849.658.5
MetaBEV-MTL†L+C✓65.669.588.764.871.556.158.758.166.3
MetaBEV-MTL‡L+C✓65.469.888.564.971.856.761.158.266.9
", + "image_path": "22dc5fd1f853a27b986332f09aa5060174728a37a126b24075735516bc2fa7e7.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 323, + 546, + 369 + ], + "lines": [ + { + "bbox": [ + 46, + 323, + 546, + 369 + ], + "spans": [ + { + "bbox": [ + 46, + 323, + 546, + 369 + ], + "type": "text", + "content": "Table 1. Comparisons with SoTA methods on nuScenes val set. We use -C and -T to denote equipping MetaBEV with the CenterPoint head [38] and Transfusion head [1]. MTL stands for testing multi-tasks with the same model. † and ‡ stand for separating or sharing the BEV feature encoder, respectively. MetaBEV outperforms the SoTA multi-modal fusion methods by +4.7% mIOU on nuScenes(val) BEV map segmentation and achieves comparable 3D object detection performance. MetaBEV also performs best in multi-task learning." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 382, + 287, + 406 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 382, + 287, + 406 + ], + "spans": [ + { + "bbox": [ + 46, + 382, + 287, + 406 + ], + "type": "text", + "content": "ing. Importantly, this approach requires only one set of pretrained weights for all the model's deployment." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 417, + 128, + 431 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 417, + 128, + 431 + ], + "spans": [ + { + "bbox": [ + 47, + 417, + 128, + 431 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 437, + 287, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 437, + 287, + 498 + ], + "spans": [ + { + "bbox": [ + 46, + 437, + 287, + 498 + ], + "type": "text", + "content": "In this section, we detail the implementations and experimental settings on both sensor failures and tasks conflict. The performances on 3D detection and BEV map segmentation are presented to validate the effectiveness, flexibility, and robustness of our MetaBEV." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 505, + 180, + 517 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 505, + 180, + 517 + ], + "spans": [ + { + "bbox": [ + 47, + 505, + 180, + 517 + ], + "type": "text", + "content": "4.1. Implementation Details" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 523, + 287, + 643 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 523, + 287, + 643 + ], + "spans": [ + { + "bbox": [ + 46, + 523, + 287, + 643 + ], + "type": "text", + "content": "Network Architectures. Swin-T [24] and VoxelNet [41] are adopted as feature encoders for the cameras and LiDAR, respectively. In the BEV-Evolving decoder, we employ four cross-modal attention layers and two self-attention layers to produce a fused BEV. We initialize the meta-BEV with a resolution of " + }, + { + "bbox": [ + 46, + 523, + 287, + 643 + ], + "type": "inline_equation", + "content": "180 \\times 180" + }, + { + "bbox": [ + 46, + 523, + 287, + 643 + ], + "type": "text", + "content": " to capture fine-grained correlations. Subsequently, we apply an FPN layer [23] to generate multi-scale features from the fused BEV. Unless specified otherwise, we use a Transformer head for 3D detection [1, 4, 34] and a CNN head [25] for map segmentation." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "type": "text", + "content": "Datasets and Evaluation Metrics. We evaluate MetaBEV on nuScenes [3], a large-scale multi-modal dataset for 3D detection and map segmentation. The dataset is split into 700/150/150 scenes for training/validation/testing. It contains data from multiple sensors, including six cameras, one" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 382, + 545, + 502 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 382, + 545, + 502 + ], + "spans": [ + { + "bbox": [ + 304, + 382, + 545, + 502 + ], + "type": "text", + "content": "LiDAR, and five radars. For camera inputs, each frame consists of six views of the surrounding environment at one specific timestamp. We resize the input views to " + }, + { + "bbox": [ + 304, + 382, + 545, + 502 + ], + "type": "inline_equation", + "content": "256 \\times 704" + }, + { + "bbox": [ + 304, + 382, + 545, + 502 + ], + "type": "text", + "content": " resolution and voxelize the point cloud to " + }, + { + "bbox": [ + 304, + 382, + 545, + 502 + ], + "type": "inline_equation", + "content": "0.075\\mathrm{m}" + }, + { + "bbox": [ + 304, + 382, + 545, + 502 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 382, + 545, + 502 + ], + "type": "inline_equation", + "content": "0.1\\mathrm{m}" + }, + { + "bbox": [ + 304, + 382, + 545, + 502 + ], + "type": "text", + "content": " for detection and segmentation, respectively. Our evaluation metrics align with [3]. For 3D detection, we utilize the standard nuScenes Detection Score (NDS) and mean Average Precision (mAP). For BEV map segmentation, we follow [25] to calculate the Mean Intersection over Union (mIoU) for map segmentation on the overall six categories." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 509, + 546, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 509, + 546, + 641 + ], + "spans": [ + { + "bbox": [ + 304, + 509, + 546, + 641 + ], + "type": "text", + "content": "Training configurations. We follow the image and LiDAR data augmentation strategies from MMDetection3D [9] to enlarge the training samples' diversities. AdamW [26] is utilized with a weight decay of 0.05 and a cyclical learning rate schedule [30] for optimization. We take overall 26 training epochs for 3D detection, and 20 epochs for BEV map segmentation, with CBGS [42] to balance the data sampling. MetaBEV is trained on 8 A100 GPUs. For the switched-modality training, the training ratios for camera/LiDAR/both are uniformly set to be " + }, + { + "bbox": [ + 304, + 509, + 546, + 641 + ], + "type": "inline_equation", + "content": "1/3" + }, + { + "bbox": [ + 304, + 509, + 546, + 641 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 509, + 546, + 641 + ], + "type": "inline_equation", + "content": "1/3" + }, + { + "bbox": [ + 304, + 509, + 546, + 641 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 509, + 546, + 641 + ], + "type": "inline_equation", + "content": "1/3" + }, + { + "bbox": [ + 304, + 509, + 546, + 641 + ], + "type": "text", + "content": ", respectively. Further details are available in the appendix." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 647, + 473, + 659 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 647, + 473, + 659 + ], + "spans": [ + { + "bbox": [ + 306, + 647, + 473, + 659 + ], + "type": "text", + "content": "4.2. Performance on full modalities" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 665, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 665, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 306, + 665, + 546, + 713 + ], + "type": "text", + "content": "We evaluate MetaBEV on 3D object detection and BEV map segmentation, utilizing either single or full modality inputs. Note that the BEV feature map size in MetaBEV is " + }, + { + "bbox": [ + 306, + 665, + 546, + 713 + ], + "type": "inline_equation", + "content": "180 \\times 180" + }, + { + "bbox": [ + 306, + 665, + 546, + 713 + ], + "type": "text", + "content": ", which is consistent with the BEV query utilized" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "8726" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 70, + 544, + 135 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 544, + 135 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 544, + 135 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 544, + 135 + ], + "type": "table", + "html": "
MethodsCamera + LidarMissing CameraMissing LiDAR
mAPNDSmIoUmAPNDSmIoUmAPNDSmIoU
TransFusion [1]67.371.2-61.667.4----
BEVFusion [25]68.571.462.761.867.54.10.57.136.7
MetaBEV68.071.570.463.669.253.739.042.654.4
", + "image_path": "ea1697386a239936f8c29d172f4c4d0a81add86766d294e86f37ec96d55351b9.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 50, + 178, + 544, + 270 + ], + "blocks": [ + { + "bbox": [ + 47, + 137, + 546, + 172 + ], + "lines": [ + { + "bbox": [ + 47, + 137, + 546, + 172 + ], + "spans": [ + { + "bbox": [ + 47, + 137, + 546, + 172 + ], + "type": "text", + "content": "Table 2. Experimental comparisons on extreme sensor missing. MetaBEV is able to totally drop the features from the missing modalities for inference, while others cannot. We attempt to replace the missing features with zero in other works so that they can output results, which are colored as blue. MetaBEV still consistently outperforms prior works when facing extreme sensor absence." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 178, + 544, + 270 + ], + "lines": [ + { + "bbox": [ + 50, + 178, + 544, + 270 + ], + "spans": [ + { + "bbox": [ + 50, + 178, + 544, + 270 + ], + "type": "table", + "html": "
MethodsEvaluationLimited Field [-60,60]Missing Objects rate=1.0Beam Reduction 4 beamsView Drop 6 dropsView Noise 6 noiseObstacle Occlusion w occlusion
NDSmIoUNDSmIoUNDSmIoUNDSmIoUNDSmIoUNDSmIoU
BEVFusion [25]zero-shot41.647.262.161.858.355.367.54.166.925.868.645.8
MetaBEV47.061.262.569.257.764.368.343.568.045.270.061.2
BEVFusion [25]in-domain42.655.565.261.951.259.068.352.868.353.169.759.3
MetaBEV54.362.168.569.954.666.469.367.969.267.570.370.2
", + "image_path": "b9f4520858cd7caf705fc533c004e2ef494a20f5c5e22b4e09204697e14b9caa.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 274, + 546, + 298 + ], + "lines": [ + { + "bbox": [ + 47, + 274, + 546, + 298 + ], + "spans": [ + { + "bbox": [ + 47, + 274, + 546, + 298 + ], + "type": "text", + "content": "Table 3. Experimental comparisons on sensor corruptions. Texts in blue denote the corruption degree. More detailed results are available in the appendix. MetaBEV consistently outperforms BEVFusion on various sensor corruptions in zero-shot and in-domain tests." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "spans": [ + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": "in BEVFormer, thus being fairly compared. For 3D object detection, results in Tab. 1 show that MetaBEV achieves superior performance with the camera modality, and gets comparable performance to the state-of-the-art with both Li-DAR and multi-modalities. For example, with CenterPoint-3D [38], MetaBEV-C achieves an impressive " + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "60.4\\%" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": " NDS on nuScenes val set with camera inputs, for LiDAR and multi-modal inputs, MetaBEV gains " + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "69.3\\%" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "71.5\\%" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": ", respectively, which is comparable to several SoTA methods. We also notice that though MetaBEV exhibits a slightly lower mAP with full-modality inputs, it still achieves superior NDS with improved orientation estimation (" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "27.2\\%" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": " vs. " + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "30.4\\%" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": " mAOE) as well as distance evaluation (" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "28.0\\%" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": " vs. " + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "28.7\\%" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": " mATE) in such the case. Moreover, it is experimentally found that MetaBEV is effective in capturing fine-grained features for dense predictions, e.g., semantic prediction. For single-modality inputs, with only several MLP heads for prediction, MetaBEV achieves a " + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "59.3\\%" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": " mIoU on cameras, and an impressive " + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "64.8\\%" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": " mIoU on LiDAR " + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "(+16.2\\%)" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": " higher than BEVFusion [25]). Moreover, results in Tab. 1 show we set a new state-of-the-art (SOTA) performance of " + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "70.4\\%" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": " mIoU on BEV map segmentation, outperforming the previous best model [2] with " + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "+4.7\\%" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": " mIoU and the second-best method [25] by " + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "inline_equation", + "content": "+7.7\\%" + }, + { + "bbox": [ + 46, + 316, + 289, + 605 + ], + "type": "text", + "content": " mIoU." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 611, + 198, + 624 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 611, + 198, + 624 + ], + "spans": [ + { + "bbox": [ + 47, + 611, + 198, + 624 + ], + "type": "text", + "content": "4.3. Performance on corruption" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "content": "We proceed to evaluate MetaBEV under various sensor failure cases, including complete sensor missing and various sensor corruptions. For the sensor missing, we train MetaBEV with the switched modality scheme, as described in Sec. 3.4. Previous fusion-based approaches, such as BEVFusion [25] and TransFusion [1], heavily rely on multi-modal features and cannot explicitly handle the ab" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "spans": [ + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "text", + "content": "sence of features caused by sensor missing. Nevertheless, we attempt to replace missing modalities with zero-initialized features for them, allowing the prior methods for predictions. Results in Tab. 2 show that MetaBEV demonstrates a stronger anti-corruption ability. Specifically, in case of missing LiDAR, MetaBEV improves " + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "inline_equation", + "content": "+35.5\\%" + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "text", + "content": " detection NDS and " + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "inline_equation", + "content": "+17.7\\%" + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "text", + "content": " segmentation mAP upon BEVFusion [25]; when encountering missing cameras, MetaBEV surpasses BEVFusion [25] by " + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "inline_equation", + "content": "+1.7\\%" + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "text", + "content": " NDS and " + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "inline_equation", + "content": "49.5\\%" + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "text", + "content": " mIoU. Notably, even when the cameras are missing, MetaBEV still achieves " + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "inline_equation", + "content": "53.7\\%" + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "text", + "content": " mIoU, surpassing the SoTA LiDAR-Only methods by " + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "inline_equation", + "content": "5.1\\%" + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "text", + "content": " (i.e., CenterPoint [38]) and " + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "inline_equation", + "content": "9.9\\%" + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "text", + "content": " (i.e., PointPillars [16]); and when the LiDAR is missing, MetaBEV even outperforms the camera-specific BEVFusion by " + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "inline_equation", + "content": "+1.4\\%" + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "text", + "content": " NDS " + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "inline_equation", + "content": "(42.6\\%" + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "text", + "content": " v.s. " + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "inline_equation", + "content": "41.2\\%)" + }, + { + "bbox": [ + 304, + 316, + 547, + 497 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 533, + 548, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 548, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 548, + 714 + ], + "type": "text", + "content": "On the other hand, we conducted both zero-shot and in-domain tests on sensor corruptions. To evaluate the model's abilities in performing with unseen corrupted or missing data, we performed the zero-shot test by directly evaluating a trained model on such data. For the in-domain test, we train MetaBEV on corrupted data with random degrees, and then conduct evaluations on noise data with one specific degree. Tab.3 shows MetaBEV outperforms BEVFusion [25] on 11/12 corruptions on zero-shot evaluation. Moreover, when trained with randomly corrupted data, MetaBEV consistently outperformed BEVFusion. The results indicate that the fusion module, which is composed of CNNs (e.g., BEVFusion), has limited representational capabilities for corrupted data, while our approach leverages the attention mechanism for efficient modeling." + } + ] + } + ], + "index": 8 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 758 + ], + "type": "text", + "content": "8727" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 71, + 286, + 159 + ], + "blocks": [ + { + "bbox": [ + 50, + 71, + 286, + 159 + ], + "lines": [ + { + "bbox": [ + 50, + 71, + 286, + 159 + ], + "spans": [ + { + "bbox": [ + 50, + 71, + 286, + 159 + ], + "type": "table", + "html": "
mAPNDSmIoU
Detection only67.671.0-
Segmentation only--70.4
H-MoER-MoE
XX64.869.464.7
✓X65.6 (+0.8)69.5 (+0.1)66.3 (+1.6)
X✓65.4 (+0.6)69.8 (+0.4)66.9 (+2.2)
", + "image_path": "4a8cfaaa028b2a552364803a5a4de143deb3f872e7121a7afd7e70db57250ac6.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 49, + 199, + 286, + 242 + ], + "blocks": [ + { + "bbox": [ + 47, + 167, + 288, + 191 + ], + "lines": [ + { + "bbox": [ + 47, + 167, + 288, + 191 + ], + "spans": [ + { + "bbox": [ + 47, + 167, + 288, + 191 + ], + "type": "text", + "content": "Table 4. We experiment on two kinds of MoE structures for Multi-Task Learning, and both show significant advantages." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 49, + 199, + 286, + 242 + ], + "lines": [ + { + "bbox": [ + 49, + 199, + 286, + 242 + ], + "spans": [ + { + "bbox": [ + 49, + 199, + 286, + 242 + ], + "type": "table", + "html": "
Method#Params.(M)mAPNDS#Params.(M)mIoU
BEVFusion40.868.571.443.162.7
BEVFusion (Heavy)54.167.270.156.165.9
MetaBEV53.568.071.555.970.4
", + "image_path": "6de81b49d851561bb8c492430d354a035dd9590c80a638076524df11a0e47b1c.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 250, + 288, + 273 + ], + "lines": [ + { + "bbox": [ + 47, + 250, + 288, + 273 + ], + "spans": [ + { + "bbox": [ + 47, + 250, + 288, + 273 + ], + "type": "text", + "content": "Table 5. Comparisons on 3D detection and BEV-Map segmentation." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 47, + 289, + 243, + 303 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 289, + 243, + 303 + ], + "spans": [ + { + "bbox": [ + 47, + 289, + 243, + 303 + ], + "type": "text", + "content": "4.4. Performance in Multi-Task Learning" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "spans": [ + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "text", + "content": "Tab. 4 presents the results of our multi-task learning (MTL) experiments for 3D object detection and BEV map segmentation. We begin with the framework designed for independent single-task learning with distinct task-specific heads and loaded a set of weights trained on multi-modal detection as pretrain. The model achieves " + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "inline_equation", + "content": "69.4\\%" + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "text", + "content": " NDS and " + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "inline_equation", + "content": "64.7\\%" + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "text", + "content": " mIoU for detection and segmentation, respectively, which is already a state-of-the-art performance. In light of this, we implement an MoE structure to help alleviate the gradient-conflict problem in MTL. Intuitively, we introduce a routing-based MoE structure, referred to as " + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "inline_equation", + "content": "\\mathrm{RM}^2\\mathrm{oE}" + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "text", + "content": ", to replace the vanilla MLP layer. This implementation results in a remarkable improvement of " + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "inline_equation", + "content": "0.4\\%" + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "text", + "content": " NDS in detection and " + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "inline_equation", + "content": "2.2\\%" + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "text", + "content": " mIoU in segmentation. Considering the additional computation required by the routing mechanisms, we propose to further experiment on a simplified version " + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "inline_equation", + "content": "\\mathrm{HM}^2\\mathrm{oE}" + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "text", + "content": " where the number of experts is adjusted to match that of the tasks, and the routing function is removed. We find it still achieves a notable improvement of " + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "inline_equation", + "content": "0.1\\%" + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "text", + "content": " NDS and " + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "inline_equation", + "content": "1.6\\%" + }, + { + "bbox": [ + 46, + 308, + 289, + 559 + ], + "type": "text", + "content": " mIoU. Upon the evaluation results, both implementations mitigate performance degradation in MTL to some extent." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 566, + 148, + 578 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 566, + 148, + 578 + ], + "spans": [ + { + "bbox": [ + 47, + 566, + 148, + 578 + ], + "type": "text", + "content": "4.5. Ablation Studies" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 584, + 287, + 633 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 584, + 287, + 633 + ], + "spans": [ + { + "bbox": [ + 46, + 584, + 287, + 633 + ], + "type": "text", + "content": "Setup. We present the ablation studies for analyzing the network architectures and training schemes. All the ablation studies are performed on nuScenes validation set, with the training configurations set as default in Sec. 4.1." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "text", + "content": "Network Configurations. We first explore the optimal architectures of the BEV-Evolving Decoder. Specifically, we analyze three components, including the combination of the layers, reference points number (" + }, + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "inline_equation", + "content": "p" + }, + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "text", + "content": " in Eq.1), and expert number (" + }, + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "inline_equation", + "content": "E" + }, + { + "bbox": [ + 46, + 641, + 288, + 715 + ], + "type": "text", + "content": " in Eq.2). Our findings in Tab. 6a indicate that a few layers of cross-attention are sufficient to produce effec" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 72, + 545, + 323 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 323 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 323 + ], + "type": "text", + "content": "tive predictions while stacking more cross-attention layers does not necessarily enhance the model's capacities (68.3% and 68.2% NDS for 6 and 8 cross-attention layers, respectively). The same findings also suit the reference points number, where increasing the sampling points does not necessarily lead to better performance, as shown in Tab. 6b. On the contrary, we discovered that simply adding two layers of self-attention after the cross-attention layers significantly improve the prediction performance by +1.1% NDS in Tab. 6a. As mentioned in Sec. 3.2, the hybrid designs capture both intra- and inter-correlations simultaneously, resulting in complementary modeling. Moreover, in Tab. 6c, we discover that a larger model capacity (i.e., incorporating more experts) can effectively alleviate the performance drop in 3D detection and map segmentation. Specifically, MetaBEV equipped with 2/8 expert (i.e. activating the 2 experts with the highest scores from a total of 8 experts.) achieves the best performance compared to other configurations (66.9% mIoU and 69.8% NDS), while " + }, + { + "bbox": [ + 304, + 72, + 545, + 323 + ], + "type": "inline_equation", + "content": "\\mathrm{HM}^2\\mathrm{oE}" + }, + { + "bbox": [ + 304, + 72, + 545, + 323 + ], + "type": "text", + "content": " is unaffected due to the fixed number of experts being equivalent to the number of tasks." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 333, + 545, + 596 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 333, + 545, + 596 + ], + "spans": [ + { + "bbox": [ + 304, + 333, + 545, + 596 + ], + "type": "text", + "content": "Do More Parameters Guarantee Improved Model Accuracy? We note that incorporating deformable attention does introduce additional parameters to MetaBEV; however, this increment is minimal and acceptable (i.e., 54M v.s. 41M) in relation to its functional capabilities (addressing sensor failures). Besides, compared with BEVFusion, though MetaBEV achieves modest advancements on 3D detection (+0.1% NDS), the improvement on map segmentation is remarkably significant (+7.7% mIoU), which indicates the deformable attention facilitates more in per-pixel perception. To conduct a fair comparison, we consistently introduce more fusion layers to BEVFusion. Results in Tab. 5 demonstrate that increasing parameters of BEVFusion yields an improved performance in map segmentation, while a reduction in 3D detection accuracy. The decreased performance for 3D detection may be attributed to the challenging convergence for the larger parameters. Furthermore, it is observed that BEVFusion performs poorly in both 3D detection and map segmentation when compared to MetaBEV with the same parameter amount. This finding highlights the fact that having more model parameters does not guarantee improved model accuracy." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "content": "Switched Modality Training. For the training strategy, using switched modality scheme to simulate the sensors missing, though simple, is the key to enabling MetaBEV with robust performance on completely sensor-failure scenarios. In Tab. 6d, comparing with the vanilla full-modality training approach, our proposed training strategy yields significant improvements on 3D detection by " + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "inline_equation", + "content": "+32.8\\%" + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "content": " NDS and " + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "inline_equation", + "content": "+1.0\\%" + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "content": " NDS, and improvements on map segmentation by " + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "inline_equation", + "content": "+17.9\\%" + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "content": " mIoU and " + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "inline_equation", + "content": "+16.7\\%" + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "content": " mIoU under LiDAR-missing" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8728" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 83, + 70, + 210, + 144 + ], + "blocks": [ + { + "bbox": [ + 83, + 70, + 210, + 144 + ], + "lines": [ + { + "bbox": [ + 83, + 70, + 210, + 144 + ], + "spans": [ + { + "bbox": [ + 83, + 70, + 210, + 144 + ], + "type": "table", + "html": "
LayersmAP/NDS
4 cross61.7/67.0
6 cross63.0/68.3
8 cross62.5/68.2
2 self+4 cross64.2/69.3
", + "image_path": "4a0524f56e002ad6716394d2d0784b9cd454f4832f7e31e8ef70c1bfb66040c7.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 83, + 148, + 209, + 158 + ], + "lines": [ + { + "bbox": [ + 83, + 148, + 209, + 158 + ], + "spans": [ + { + "bbox": [ + 83, + 148, + 209, + 158 + ], + "type": "text", + "content": "(a) The number of self/Cross-layer" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "type": "table", + "bbox": [ + 237, + 70, + 332, + 143 + ], + "blocks": [ + { + "bbox": [ + 237, + 70, + 332, + 143 + ], + "lines": [ + { + "bbox": [ + 237, + 70, + 332, + 143 + ], + "spans": [ + { + "bbox": [ + 237, + 70, + 332, + 143 + ], + "type": "table", + "html": "
PointsmAP/NDS
462.3/67.9
862.7/68.2
1262.3/68.0
1662.3/68.1
", + "image_path": "e20a4396cceaa04b809f10f68245170dfef9891aafe7ab1a5f7959b9cc8dc789.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 222, + 148, + 347, + 159 + ], + "lines": [ + { + "bbox": [ + 222, + 148, + 347, + 159 + ], + "spans": [ + { + "bbox": [ + 222, + 148, + 347, + 159 + ], + "type": "text", + "content": "(b) The number of reference points" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "type": "table", + "bbox": [ + 361, + 70, + 511, + 143 + ], + "blocks": [ + { + "bbox": [ + 361, + 70, + 511, + 143 + ], + "lines": [ + { + "bbox": [ + 361, + 70, + 511, + 143 + ], + "spans": [ + { + "bbox": [ + 361, + 70, + 511, + 143 + ], + "type": "table", + "html": "
ExpertsmAP/NDSmIoU
1/2 Expert65.8/69.863.3
1/4 Expert64.9/69.565.9
1/8 Expert65.4/69.766.4
2/8 Expert65.4/69.866.9
", + "image_path": "d2824f56813cebf984135fe0e9743669844be46f86c6721127d4e17791596852.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 50, + 159, + 544, + 232 + ], + "blocks": [ + { + "bbox": [ + 402, + 148, + 470, + 159 + ], + "lines": [ + { + "bbox": [ + 402, + 148, + 470, + 159 + ], + "spans": [ + { + "bbox": [ + 402, + 148, + 470, + 159 + ], + "type": "text", + "content": "(c) Expert number" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 50, + 159, + 544, + 232 + ], + "lines": [ + { + "bbox": [ + 50, + 159, + 544, + 232 + ], + "spans": [ + { + "bbox": [ + 50, + 159, + 544, + 232 + ], + "type": "table", + "html": "
TaskMetricsVanilla trainingSwitched Modality Training
Lidar-MissingCamera-MissingFullLidar-MissingCamera-MissingFull
3D detectionNDS9.868.271.042.6 (+32.8)69.2 (+1.0)71.5 (+0.5)
mAP2.962.467.439.0 (+36.1)63.6 (+1.2)68.0 (+0.6)
BEV-Map SegmentationmIoU36.527.070.454.4 (+17.9)53.7 (+16.7)68.5 (-1.9)
", + "image_path": "66a1ac3a0c60f4f0a67c665af56a9395f75980d8725781ab0ac998bcf7bbf5cd.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 46, + 235, + 546, + 258 + ], + "lines": [ + { + "bbox": [ + 46, + 235, + 546, + 258 + ], + "spans": [ + { + "bbox": [ + 46, + 235, + 546, + 258 + ], + "type": "text", + "content": "(d) Evaluation of the NuScenes val dataset when Cameras or LiDAR totally fail. We test the performance with the switched modality training on both 3D detection and BEV-map segmentation tasks." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_footnote" + }, + { + "bbox": [ + 46, + 260, + 537, + 273 + ], + "lines": [ + { + "bbox": [ + 46, + 260, + 537, + 273 + ], + "spans": [ + { + "bbox": [ + 46, + 260, + 537, + 273 + ], + "type": "text", + "content": "Table 6. Ablation studies for the model architectures and training strategy. Default settings are marked in gray in (a), (b), and (c)." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 294, + 287, + 343 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 294, + 287, + 343 + ], + "spans": [ + { + "bbox": [ + 46, + 294, + 287, + 343 + ], + "type": "text", + "content": "and camera-missing scenarios, respectively. More intriguingly, we find that the switched modality training could even enhance the model performance on full modalities, rising from " + }, + { + "bbox": [ + 46, + 294, + 287, + 343 + ], + "type": "inline_equation", + "content": "71.0\\%" + }, + { + "bbox": [ + 46, + 294, + 287, + 343 + ], + "type": "text", + "content": " NDS to " + }, + { + "bbox": [ + 46, + 294, + 287, + 343 + ], + "type": "inline_equation", + "content": "71.5\\%" + }, + { + "bbox": [ + 46, + 294, + 287, + 343 + ], + "type": "text", + "content": " NDS on 3D detection." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 354, + 119, + 366 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 354, + 119, + 366 + ], + "spans": [ + { + "bbox": [ + 47, + 354, + 119, + 366 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 46, + 375, + 289, + 531 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 375, + 289, + 531 + ], + "spans": [ + { + "bbox": [ + 46, + 375, + 289, + 531 + ], + "type": "text", + "content": "In this paper, we present a novel framework, named MetaBEV, for the purpose of solving sensor failures in the bird's-eye view (BEV) 3D detection and map segmentation. Our method integrates modal-specific layers into the cross-modal attention layer to enhance the fusion process, achieving appealing performance on full-modality inputs, and meanwhile MetaBEV effectively alleviates the significant performance degradation that is often caused by corrupted or missing sensor signals. We also introduce " + }, + { + "bbox": [ + 46, + 375, + 289, + 531 + ], + "type": "inline_equation", + "content": "\\mathbf{M}^2\\mathrm{oE}" + }, + { + "bbox": [ + 46, + 375, + 289, + 531 + ], + "type": "text", + "content": " to handle potential conflicts between tasks. We hope that MetaBEV will provide a more focused and effective approach for investigating sensor-failure scenarios in the autonomous driving field." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 542, + 287, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 542, + 287, + 651 + ], + "spans": [ + { + "bbox": [ + 46, + 542, + 287, + 651 + ], + "type": "text", + "content": "Limitations. Though we adopted the deformable attention [43] for efficiency, it unavoidably leads to a slight increase in network parameters compared to the lightweight solutions [25, 22]. Despite this, the benefits of mitigating sensor failures are highly desirable, and the additional computational overhead may be deemed acceptable. We acknowledge that lightweight networks could be an avenue for future research, potentially involving techniques such as network pruning, token reduction, etc." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "content": "Acknowledgement. This paper is partially supported by the National Key R&D Program of China No.2022ZD0161000 and the General Research Fund of Hong Kong No.17200622." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 293, + 365, + 306 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 293, + 365, + 306 + ], + "spans": [ + { + "bbox": [ + 307, + 293, + 365, + 306 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 311, + 314, + 547, + 714 + ], + "type": "list", + "angle": 0, + "index": 24, + "blocks": [ + { + "bbox": [ + 311, + 314, + 546, + 369 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 314, + 546, + 369 + ], + "spans": [ + { + "bbox": [ + 311, + 314, + 546, + 369 + ], + "type": "text", + "content": "[1] Xuyang Bai, Zeyu Hu, Xinge Zhu, Qingqiu Huang, Yilun Chen, Hongbo Fu, and Chiew-Lan Tai. Transfusion: Robust lidar-camera fusion for 3d object detection with transformers. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 311, + 371, + 547, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 371, + 547, + 426 + ], + "spans": [ + { + "bbox": [ + 311, + 371, + 547, + 426 + ], + "type": "text", + "content": "[2] Shubhankar Borse, Marvin Klingner, Varun Ravi Kumar, Hong Cai, Abdulaziz Almuzairee, Senthil Yogamani, and Fatih Porikli. X-align: Cross-modal cross-view alignment for bird's-eye-view segmentation. In IEEE/CVF Winter Conference on Applications of Computer Vision, 2023." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 311, + 428, + 547, + 483 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 428, + 547, + 483 + ], + "spans": [ + { + "bbox": [ + 311, + 428, + 547, + 483 + ], + "type": "text", + "content": "[3] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 311, + 485, + 547, + 529 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 485, + 547, + 529 + ], + "spans": [ + { + "bbox": [ + 311, + 485, + 547, + 529 + ], + "type": "text", + "content": "[4] Nicolas Carion, Francisco Massa, Gabriel Synnaeve, Nicolas Usunier, Alexander Kirillov, and Sergey Zagoruyko. End-to-end object detection with transformers. In European Conference on Computer Vision, 2020." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 311, + 531, + 547, + 575 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 531, + 547, + 575 + ], + "spans": [ + { + "bbox": [ + 311, + 531, + 547, + 575 + ], + "type": "text", + "content": "[5] Runjian Chen, Yao Mu, Runsen Xu, Wenqi Shao, Chenhan Jiang, Hang Xu, Zhenguo Li, and Ping Luo. Co^3: Cooperative unsupervised 3d representation learning for autonomous driving. arXiv preprint arXiv:2206.04028, 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 311, + 577, + 547, + 621 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 577, + 547, + 621 + ], + "spans": [ + { + "bbox": [ + 311, + 577, + 547, + 621 + ], + "type": "text", + "content": "[6] Xiaozhi Chen, Huimin Ma, Ji Wan, Bo Li, and Tian Xia. Multi-view 3d object detection network for autonomous driving. In Proceedings of the IEEE conference on Computer Vision and Pattern Recognition, 2017." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 311, + 624, + 546, + 657 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 624, + 546, + 657 + ], + "spans": [ + { + "bbox": [ + 311, + 624, + 546, + 657 + ], + "type": "text", + "content": "[7] Xuanyao Chen, Tianyuan Zhang, Yue Wang, Yilun Wang, and Hang Zhao. Futr3d: A unified sensor fusion framework for 3d detection. arXiv preprint arXiv:2203.10642, 2022." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 311, + 658, + 547, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 658, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 311, + 658, + 547, + 714 + ], + "type": "text", + "content": "[8] Aakanksha Chowdhery, Sharan Narang, Jacob Devlin, Maarten Bosma, Gaurav Mishra, Adam Roberts, Paul Barham, Hyung Won Chung, Charles Sutton, Sebastian Gehrmann, et al. Palm: Scaling language modeling with pathways. arXiv preprint arXiv:2204.02311, 2022." + } + ] + } + ], + "index": 23 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8729" + } + ] + } + ], + "index": 25 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 286, + 712 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 53, + 72, + 286, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 72, + 286, + 116 + ], + "spans": [ + { + "bbox": [ + 53, + 72, + 286, + 116 + ], + "type": "text", + "content": "[9] MMDetection3D Contributors. MMDetection3D: OpenMMLab next-generation platform for general 3D object detection. https://github.com/open-mmlab/mmdetection3d, 2020." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 118, + 286, + 171 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 118, + 286, + 171 + ], + "spans": [ + { + "bbox": [ + 48, + 118, + 286, + 171 + ], + "type": "text", + "content": "[10] Danny Driess, Fei Xia, Mehdi SM Sajjadi, Corey Lynch, Aakanksha Chowdhery, Brian Ichter, Ayzaan Wahid, Jonathan Tompson, Quan Vuong, Tianhe Yu, et al. Palme: An embodied multimodal language model. arXiv preprint arXiv:2303.03378, 2023." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 49, + 173, + 286, + 225 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 173, + 286, + 225 + ], + "spans": [ + { + "bbox": [ + 49, + 173, + 286, + 225 + ], + "type": "text", + "content": "[11] Chongjian Ge, Youwei Liang, Yibing Song, Jianbo Jiao, Jue Wang, and Ping Luo. Revitalizing cnn attention via transformers in self-supervised visual representation learning. Advances in Neural Information Processing Systems, 2021." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 49, + 228, + 286, + 270 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 228, + 286, + 270 + ], + "spans": [ + { + "bbox": [ + 49, + 228, + 286, + 270 + ], + "type": "text", + "content": "[12] Chongjian Ge, Jiangliu Wang, Zhan Tong, Shoufa Chen, Yibing Song, and Ping Luo. Soft neighbors are positive supporters in contrastive visual representation learning. arXiv preprint arXiv:2303.17142, 2023." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 49, + 272, + 286, + 326 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 272, + 286, + 326 + ], + "spans": [ + { + "bbox": [ + 49, + 272, + 286, + 326 + ], + "type": "text", + "content": "[13] Yihan Hu, Jiazhi Yang, Li Chen, Keyu Li, Chonghao Sima, Xizhou Zhu, Siqi Chai, Senyao Du, Tianwei Lin, Henhai Wang, et al. Planning-oriented autonomous driving. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2023." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 49, + 327, + 286, + 369 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 327, + 286, + 369 + ], + "spans": [ + { + "bbox": [ + 49, + 327, + 286, + 369 + ], + "type": "text", + "content": "[14] Tengteng Huang, Zhe Liu, Xiwu Chen, and Xiang Bai. Epnet: Enhancing point features with image semantics for 3d object detection. In European Conference on Computer Vision, 2020." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 49, + 372, + 286, + 425 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 372, + 286, + 425 + ], + "spans": [ + { + "bbox": [ + 49, + 372, + 286, + 425 + ], + "type": "text", + "content": "[15] Sebastian Jasczur, Aakanksha Chowdhery, Afroz Mohiuddin, Lukasz Kaiser, Wojciech Gajewski, Henryk Michalewski, and Jonni Kanerva. Sparse is enough in scaling transformers. Advances in Neural Information Processing Systems, 2021." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 49, + 426, + 286, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 426, + 286, + 470 + ], + "spans": [ + { + "bbox": [ + 49, + 426, + 286, + 470 + ], + "type": "text", + "content": "[16] Alex H Lang, Sourabh Vora, Holger Caesar, Lubing Zhou, Jiong Yang, and Oscar Beijbom. Pointpillars: Fast encoders for object detection from point clouds. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 49, + 472, + 286, + 525 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 472, + 286, + 525 + ], + "spans": [ + { + "bbox": [ + 49, + 472, + 286, + 525 + ], + "type": "text", + "content": "[17] Dmitry Lepikhin, HyoukJoong Lee, Yuanzhong Xu, Dehao Chen, Orhan First, Yanping Huang, Maxim Krikun, Noam Shazeer, and Zhifeng Chen. Gshard: Scaling giant models with conditional computation and automatic sharding. International Conference on Learning Representations, 2020." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 49, + 526, + 286, + 568 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 526, + 286, + 568 + ], + "spans": [ + { + "bbox": [ + 49, + 526, + 286, + 568 + ], + "type": "text", + "content": "[18] Yanwei Li, Yilun Chen, Xiaojuan Qi, Zeming Li, Jian Sun, and Jiaya Jia. Unifying voxel-based representation with transformer for 3d object detection. arXiv preprint arXiv:2206.00630, 2022." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 49, + 571, + 286, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 571, + 286, + 635 + ], + "spans": [ + { + "bbox": [ + 49, + 571, + 286, + 635 + ], + "type": "text", + "content": "[19] Yingwei Li, Adams Wei Yu, Tianjian Meng, Ben Caine, Jiquan Ngiam, Daiyi Peng, Junyang Shen, Yifeng Lu, Denny Zhou, Quoc V Le, et al. Deepfusion: Lidar-camera deep fusion for multi-modal 3d object detection. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 49, + 636, + 286, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 636, + 286, + 690 + ], + "spans": [ + { + "bbox": [ + 49, + 636, + 286, + 690 + ], + "type": "text", + "content": "[20] Yingwei Li, Adams Wei Yu, Tianjian Meng, Ben Caine, Ji-quan Ngiam, Daiyi Peng, Junyang Shen, Yifeng Lu, Denny Zhou, Quoc V Le, et al. Deepfusion: Lidar-camera deep fusion for multi-modal 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 49, + 692, + 286, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 49, + 692, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 49, + 692, + 286, + 712 + ], + "type": "text", + "content": "[21] Zhiqi Li, Wenhai Wang, Hongyang Li, Enze Xie, Chonghao Sima, Tong Lu, Yu Qiao, and Jifeng Dai. Bevformer:" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 106 + ], + "type": "text", + "content": "Learning bird's-eye-view representation from multi-camera images via spatiotemporal transformers. In European Conference on Computer Vision, 2022." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 308, + 107, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 107, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 308, + 107, + 545, + 150 + ], + "type": "text", + "content": "[22] Tingting Liang, Hongwei Xie, Kaicheng Yu, Zhongyu Xia, Zhiwei Lin, Yongtao Wang, Tao Tang, Bing Wang, and Zhi Tang. Bevfusion: A simple and robust lidar-camera fusion framework. arXiv preprint arXiv:2205.13790, 2022." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 152, + 545, + 195 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 152, + 545, + 195 + ], + "spans": [ + { + "bbox": [ + 308, + 152, + 545, + 195 + ], + "type": "text", + "content": "[23] Tsung-Yi Lin, Piotr Dólar, Ross Girshick, Kaiming He, Bharath Hariharan, and Serge Belongie. Feature pyramid networks for object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2017." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 197, + 545, + 250 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 197, + 545, + 250 + ], + "spans": [ + { + "bbox": [ + 308, + 197, + 545, + 250 + ], + "type": "text", + "content": "[24] Ze Liu, Yutong Lin, Yue Cao, Han Hu, Yixuan Wei, Zheng Zhang, Stephen Lin, and Baining Guo. Swin transformer: Hierarchical vision transformer using shifted windows. In IEEE/CVF International Conference on Computer Vision, 2021." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 252, + 545, + 296 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 252, + 545, + 296 + ], + "spans": [ + { + "bbox": [ + 308, + 252, + 545, + 296 + ], + "type": "text", + "content": "[25] Zhijian Liu, Haotian Tang, Alexander Amini, Xinyu Yang, Huizi Mao, Daniela Rus, and Song Han. Bevfusion: Multi-task multi-sensor fusion with unified bird's-eye view representation. arXiv preprint arXiv:2205.13542, 2022." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 297, + 545, + 319 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 297, + 545, + 319 + ], + "spans": [ + { + "bbox": [ + 308, + 297, + 545, + 319 + ], + "type": "text", + "content": "[26] Ilya Loshchilov and Frank Hutter. Decoupled weight decay regularization. arXiv preprint arXiv:1711.05101, 2017." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 320, + 545, + 353 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 320, + 545, + 353 + ], + "spans": [ + { + "bbox": [ + 308, + 320, + 545, + 353 + ], + "type": "text", + "content": "[27] Jonah Philion and Sanja Fidler. Lift, splat, shoot: Encoding images from arbitrary camera rigs by implicitly unprojecting to 3d. In European Conference on Computer Vision, 2020." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 354, + 545, + 398 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 354, + 545, + 398 + ], + "spans": [ + { + "bbox": [ + 308, + 354, + 545, + 398 + ], + "type": "text", + "content": "[28] Noam Shazeer, Azalia Mirhoseini, Krzysztof Maziarz, Andy Davis, Quoc Le, Geoffrey Hinton, and Jeff Dean. Outrageously large neural networks: The sparsely-gated mixture-of-experts layer. arXiv preprint arXiv:1701.06538, 2017." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 399, + 545, + 431 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 399, + 545, + 431 + ], + "spans": [ + { + "bbox": [ + 308, + 399, + 545, + 431 + ], + "type": "text", + "content": "[29] Vishwanath A Sindagi, Yin Zhou, and Oncel Tuzel. Mvxnet: Multimodal voxelnet for 3d object detection. In International Conference on Robotics and Automation, 2019." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 433, + 545, + 465 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 433, + 545, + 465 + ], + "spans": [ + { + "bbox": [ + 308, + 433, + 545, + 465 + ], + "type": "text", + "content": "[30] Leslie N Smith. Cyclical learning rates for training neural networks. In IEEE/CVF Winter Conference on Applications of Computer Vision, 2017." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 468, + 545, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 468, + 545, + 510 + ], + "spans": [ + { + "bbox": [ + 308, + 468, + 545, + 510 + ], + "type": "text", + "content": "[31] Sourabh Vora, Alex H Lang, Bassam Helou, and Oscar Beijbom. Pointpainting: Sequential fusion for 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 512, + 545, + 555 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 512, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 308, + 512, + 545, + 555 + ], + "type": "text", + "content": "[32] Chunwei Wang, Chao Ma, Ming Zhu, and Xiaokang Yang. Pointaugmenting: Cross-modal augmentation for 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 557, + 545, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 557, + 545, + 600 + ], + "spans": [ + { + "bbox": [ + 308, + 557, + 545, + 600 + ], + "type": "text", + "content": "[33] Xin Wang, Fisher Yu, Lisa Dunlap, Yi-An Ma, Ruth Wang, Azalia Mirhoseini, Trevor Darrell, and Joseph E Gonzalez. Deep mixture of experts via shallow embedding. In Uncertainty in artificial intelligence, pages 552-562, 2020." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 601, + 545, + 645 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 601, + 545, + 645 + ], + "spans": [ + { + "bbox": [ + 308, + 601, + 545, + 645 + ], + "type": "text", + "content": "[34] Yue Wang, Vitor Campagnolo Guizilini, Tianyuan Zhang, Yilun Wang, Hang Zhao, and Justin Solomon. Detr3d: 3d object detection from multi-view images via 3d-to-2d queries. In Conference on Robot Learning, 2022." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 647, + 545, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 647, + 545, + 679 + ], + "spans": [ + { + "bbox": [ + 308, + 647, + 545, + 679 + ], + "type": "text", + "content": "[35] Barret Zoph William Fedus and Noam Shazeer. Switch transformers: Scaling to trillion parameter models with simple and efficient sparsity. Computer Research Repository, 2021." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 681, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 681, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 308, + 681, + 545, + 712 + ], + "type": "text", + "content": "[36] Enze Xie, Zhiding Yu, Daquan Zhou, Jonah Philion, Anima Anandkumar, Sanja Fidler, Ping Luo, and Jose M Alvarez. M^2bev: Multi-camera joint 3d detection and segmentation" + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "8730" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 386 + ], + "type": "list", + "angle": 0, + "index": 8, + "blocks": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "text", + "content": "with unified birds-eye view representation. arXiv preprint arXiv:2204.05088, 2022." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 140 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 140 + ], + "type": "text", + "content": "[37] Brandon Yang, Gabriel Bender, Quoc V Le, and Jiquan Ngiam. Condconv: Conditionally parameterized convolutions for efficient inference. Advances in Neural Information Processing Systems, 2019." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 141, + 287, + 174 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 141, + 287, + 174 + ], + "spans": [ + { + "bbox": [ + 48, + 141, + 287, + 174 + ], + "type": "text", + "content": "[38] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Center-based 3d object detection and tracking. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 175, + 287, + 207 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 175, + 287, + 207 + ], + "spans": [ + { + "bbox": [ + 48, + 175, + 287, + 207 + ], + "type": "text", + "content": "[39] Tianwei Yin, Xingyi Zhou, and Philipp Krahenbuhl. Multimodal virtual point 3d detection. Advances in Neural Information Processing Systems, 2021." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 209, + 287, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 209, + 287, + 262 + ], + "spans": [ + { + "bbox": [ + 48, + 209, + 287, + 262 + ], + "type": "text", + "content": "[40] Kaicheng Yu, Tang Tao, Hongwei Xie, Zhiwei Lin, Zhongwei Wu, Zhongyu Xia, Tingting Liang, Haiyang Sun, Jiong Deng, Dayang Hao, et al. Benchmarking the robustness of lidar-camera fusion for 3d object detection. arXiv preprint arXiv:2205.14951, 2022." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 264, + 287, + 297 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 264, + 287, + 297 + ], + "spans": [ + { + "bbox": [ + 48, + 264, + 287, + 297 + ], + "type": "text", + "content": "[41] Yin Zhou and Oncel Tuzel. Voxelnet: End-to-end learning for point cloud based 3d object detection. In IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2018." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 299, + 287, + 341 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 299, + 287, + 341 + ], + "spans": [ + { + "bbox": [ + 48, + 299, + 287, + 341 + ], + "type": "text", + "content": "[42] Benjin Zhu, Zhengkai Jiang, Xiangxin Zhou, Zeming Li, and Gang Yu. Class-balanced grouping and sampling for point cloud 3d object detection. arXiv preprint arXiv:1908.09492, 2019." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 343, + 287, + 386 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 343, + 287, + 386 + ], + "spans": [ + { + "bbox": [ + 48, + 343, + 287, + 386 + ], + "type": "text", + "content": "[43] Xizhou Zhu, Weijie Su, Lewei Lu, Bin Li, Xiaogang Wang, and Jifeng Dai. Deformable detr: Deformable transformers for end-to-end object detection. arXiv preprint arXiv:2010.04159, 2020." + } + ] + } + ], + "index": 7 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 314, + 757 + ], + "type": "text", + "content": "8731" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/ed6327a3-66bd-4260-9c23-011c9182cd69_content_list.json b/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/ed6327a3-66bd-4260-9c23-011c9182cd69_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..5294c68c4d8ca03e650414237841e7c7b53559ad --- /dev/null +++ b/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/ed6327a3-66bd-4260-9c23-011c9182cd69_content_list.json @@ -0,0 +1,2253 @@ +[ + { + "type": "text", + "text": "MetaF2N: Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces", + "text_level": 1, + "bbox": [ + 253, + 181, + 715, + 220 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Zhicun Yin $^{1}$ Ming Liu $^{1(\\boxtimes)}$ Xiaoming Li $^{1}$ Hui Yang $^{2}$", + "bbox": [ + 260, + 251, + 704, + 268 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Longan Xiao2 Wangmeng Zuo1,3", + "bbox": [ + 352, + 268, + 616, + 283 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{1}$ Harbin Institute of Technology $^{2}$ Shanghai Transsion Co, Ltd $^{3}$ Peng Cheng Laboratory", + "bbox": [ + 141, + 283, + 831, + 298 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "cszcyin@outlook.com, csmliu@outlook.com, csxml@gmail.com, wmzuo@hit.edu.cn", + "bbox": [ + 174, + 301, + 796, + 312 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 250, + 343, + 322, + 356 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Due to their highly structured characteristics, faces are easier to recover than natural scenes for blind image super-resolution. Therefore, we can extract the degradation representation of an image from the low-quality and recovered face pairs. Using the degradation representation, realistic low-quality images can then be synthesized to fine-tune the super-resolution model for the real-world low-quality image. However, such a procedure is time-consuming and laborious, and the gaps between recovered faces and the ground-truths further increase the optimization uncertainty. To facilitate efficient model adaptation towards image-specific degradations, we propose a method dubbed MetaF2N, which leverages the contained Faces to fine-tune model parameters for adapting to the whole Natural image in a Meta-learning framework. The degradation extraction and low-quality image synthesis steps are thus circumvented in our MetaF2N, and it requires only one fine-tuning step to get decent performance. Considering the gaps between the recovered faces and groundtruths, we further deploy a MaskNet for adaptively predicting loss weights at different positions to reduce the impact of low-confidence areas. To evaluate our proposed MetaF2N, we have collected a real-world low-quality dataset with one or multiple faces in each image, and our MetaF2N achieves superior performance on both synthetic and real-world datasets. Source code, pre-trained models, and collected datasets are available at https://github.com/yinzhicun/MetaF2N.", + "bbox": [ + 100, + 370, + 473, + 733 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 102, + 756, + 225, + 770 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "With the development of dataset construction, network design, and many other relevant methods, blind image super-resolution (SR) [9, 33] has acquired enormous progress in recent years. To construct pairwise low-/high-quality samples for training the image SR models, typically", + "bbox": [ + 100, + 777, + 470, + 844 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "one can capture low- and high-quality pairs by adjusting the focal length of cameras [5, 55, 61] and shooting distance [8], or synthesize low-quality images via degradation modeling [26, 51, 59]. However, these methods can only cover a limited and biased range of degradations, which is insufficient for real-world applications. Besides, most existing blind image SR methods [51, 59] train a static model for all testing scenarios, greatly limiting their flexibility and generalization ability.", + "bbox": [ + 497, + 344, + 868, + 461 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In order to break the restriction of limited training sets, self-supervised learning has been introduced to train a model for each low-quality image, without requiring pairwise ground-truths [10, 42, 47]. Although these methods exhibit a great deal of flexibility, they largely rely on certain priors or assumptions, showing inferior image SR performance. Recently, Li et al. [26] reached a better compromise on the requirement of ground-truths and proposed ReDegNet by leveraging the faces contained in natural images. In specific, the face regions in a real-world low-quality natural image are processed via blind face SR methods [36, 50, 57, 63], which have achieved appealing results thanks to the highly structured characteristics of faces. Then, the low-quality and recovered face pairs can be utilized to model the degradations in the image. Finally, more low-quality images are synthesized with the degradation representations for fine-tuning the SR model. With the above design, ReDegNet [26] is flexible to process a single image or a batch of images with diverse degradations.", + "bbox": [ + 497, + 464, + 868, + 712 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Although ReDegNet [26] achieves superior SR performance, especially in specific scenarios (i.e., fine-tuning with faces within the test image), there are still several limitations. On the one hand, the training procedure is time-consuming and computationally intensive, where the modules for degradation representation extraction and low-quality image synthesis are jointly optimized. Furthermore, when the model is intended to deal with a single low-quality image, it is difficult to determine when to terminate the training process for avoiding under-fitting or over-fitting.", + "bbox": [ + 497, + 713, + 868, + 845 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 95, + 8, + 169, + 46 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 231, + 7, + 815, + 48 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "13033", + "bbox": [ + 465, + 875, + 504, + 885 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "On the other hand, even though the faces processed by the blind face restoration methods show appealing quality, there inevitably exist gaps between the recovered faces and the real ground-truths. Such gaps may affect the degradation representation accuracy and further hamper the training of the SR model. These problems have a large impact on the SR performance, especially when the model is fine-tuned for image-specific super-resolution.", + "bbox": [ + 100, + 148, + 470, + 251 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To remedy the aforementioned problems regarding training efforts and data gaps, we propose an efficient and effective method dubbed MetaF2N. In specific, the SR model directly fine-tunes the parameters from the low-quality and recovered face pairs, then uses the fine-tuned parameters to process the whole natural image. As such, the cumbersome degradation extraction and low-quality image synthesis steps are circumvented in our method, which avoids the interference of degradation modeling errors. In order to stabilize and accelerate the fine-tuning process during inference, we adopt the model-agnostic meta-learning [11] framework in the training phase, resulting in a much more practical model adaptation procedure that can be finished in a single fine-tuning step.", + "bbox": [ + 100, + 252, + 473, + 434 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Additionally, considering the gaps between low-quality faces and that processed by blind face restoration methods, we argue that treating all pixels equally will magnify the effect of the errors. Therefore, we further deploy a MaskNet, which adaptively predicts loss weights for different positions, to fulfill that the recovered face regions more similar to the ground-truths are assigned with higher loss weights. Ideally, the weight map should be extracted from the recovered faces and the ground-truths. Unfortunately, the ground-truths are unavailable during inference. Considering that predicting the loss weight map is similar to the image quality assessment (IQA) task, following the idea of degraded-reference IQA methods [2, 62], the MaskNet instead takes the low-quality and recovered faces as input. According to our observation, typically the areas closer to the ground-truth are assigned with larger weights and vice versa, which is consistent with the intuitions.", + "bbox": [ + 100, + 434, + 473, + 652 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "For evaluating the proposed MetaF2N, we have constructed several synthetic datasets based on FFHQ [21] and CelebA [34]. To further show the effectiveness under real-world scenarios, we have also collected a real-world low-quality image dataset from the Internet and existing datasets, namely RealFaces200 (RF200), which contains a single face or multiple faces in each image. Extensive experiments show that our MetaF2N achieves superior performance on both synthetic and real-world datasets.", + "bbox": [ + 100, + 654, + 470, + 769 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In summary, the contribution of this paper includes,", + "bbox": [ + 119, + 771, + 442, + 783 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "- We propose an efficient and effective method dubbed MetaF2N for blind image super-resolution, which takes advances of blind face restoration models and learns model adaptation from the face regions with", + "bbox": [ + 119, + 792, + 473, + 844 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "only one fine-tuning step.", + "bbox": [ + 529, + 149, + 692, + 162 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- Considering that the gaps between faces recovered by blind face restoration methods and the ground-truth ones may result in an inaccurate degradation modeling, a MaskNet is introduced for confidence prediction to mitigate the effect of the gaps.", + "- A real-world low-quality image dataset with one or multiple faces in each image is collected, which will be helpful for face-guided blind image super-resolution." + ], + "bbox": [ + 515, + 169, + 868, + 283 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 499, + 294, + 633, + 309 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Recent efforts on blind image SR are mainly devoted to network design and data construction. We recommend [9, 33] for a comprehensive review of blind image SR, and focus on the most relevant methods of data construction, which are orthogonal to network design. We also briefly review recent advances in blind face restoration and meta-learning, which settle the foundation of this work.", + "bbox": [ + 497, + 317, + 868, + 408 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Blind Image Super-Resolution", + "text_level": 1, + "bbox": [ + 499, + 416, + 752, + 429 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Pairwise Data. Recent methods have made great efforts towards pairwise datasets that cover a wider range of real-world degradations and are better aligned. The most intuitive way is to collect pairwise samples. For example, Chen et al. [8] collected a City100 dataset by a DSLR and a smartphone via focal length and shooting distance adjustment, respectively. Since City100 was captured via postcards ignoring the geometries, Cai et al. [5] and Wei et al. [55] proposed to capture image pairs in real-world scenes and collected two datasets RealSR and DRealSR. Joze et al. [20] instead captured a dataset ImagePairs by embedding two cameras with different resolutions into a beam splitter. Another approach is to synthesize low-quality images from high-quality ones. Early methods [15, 18, 19, 53] utilized classical degradation models composed of blur, down-sampling, noise, etc., which are insufficient to model the real-world degradations. Zhang et al. [59] and Wang et al. [51] proposed to mimic real-world degradations via random combinations of different degradations. Albeit their progress on general image SR, these methods still cover a limited and biased range of real-world degradations.", + "bbox": [ + 497, + 435, + 868, + 709 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Unpaired Data. For better utilizing unpaired low-quality images that are easier to collect, some methods [12, 49, 58] proposed to extract the degradation representations or directly learn low-quality image synthesis in an unsupervised manner. Some methods [42, 47] utilized the texture recurrence across different scales or the priors embraced in the model learning process, and achieved image-specific blind image super-resolution in a self-supervised scheme. Purely relying on the unpaired samples or solely the low-quality ones, these methods may cover more degradations yet have", + "bbox": [ + 497, + 714, + 868, + 844 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "13034", + "bbox": [ + 465, + 875, + 505, + 885 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "unsatisfactory performance in most cases. As a compromise, Li et al. [26] utilized the highly structured faces in real-world low-quality images, and extracted degradation representations from the low-quality faces and their counterparts recovered by blind face restoration methods. In this work, we take a step forward to solve the problems of Li et al. [26] and propose a MetaF2N framework for effective blind image SR of LR natural images containing faces.", + "bbox": [ + 100, + 148, + 472, + 252 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Blind Face Restoration", + "text_level": 1, + "bbox": [ + 102, + 262, + 302, + 275 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The diverse structures and complicated degradation jointly exacerbate the difficulties of blind natural image SR. In contrast, recent methods tend to leverage the structure information of specific images (e.g., faces [27-30, 57, 63] and text [31]), which have exhibited superior performance. Li et al. [28, 29] suggested using high-quality image(s) of the same person to provide personalized guidance. More general face restoration methods focused on constructing dictionaries [16, 27, 30, 54], semantic maps [7], or codebooks [63]. Recently, the generative structure prior based methods [6, 50, 57, 64] leveraged the representative pretrained StyleGAN models [22] and showed tremendous improvement in restoring fine-grained textures. Compared with natural images, these methods showed great generalization abilities, even in the presence of unknown degradations. This property has motivated us to employ face images on the inner loop of meta-learning to benefit the optimization toward better natural image SR.", + "bbox": [ + 100, + 283, + 473, + 517 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.3. Image Super-Resolution with Meta-Learning", + "text_level": 1, + "bbox": [ + 102, + 527, + 460, + 541 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Meta-learning aims to learn adaptation to new domains or tasks by leveraging existing ones, which has demonstrated excellent generalization ability in many tasks [11, 14, 37, 40, 44, 45, 48]. Early works like MZSR [43] and MLSR [41] utilized meta-learning techniques to obtain a better initialization of model parameters that can be efficiently adapted to new low-quality images. Meta-KernelGAN [25] utilized meta-learning for efficient kernel estimation, which can be combined with non-blind SR methods. As one can see, MZSR [43] and MLSR [41] heavily rely on known degradations to construct inner loop supervisions, while Meta-KernelGAN is also restricted due to that the degradation representations formulated by kernels cannot well describe many real-world degradations. In this work, we adopt face regions as inner loop supervision and get rid of explicit degradation representations, which is more practical for real-world scenarios.", + "bbox": [ + 100, + 548, + 472, + 769 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Preliminary", + "text_level": 1, + "bbox": [ + 102, + 782, + 220, + 796 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "For efficiently utilizing the generalization ability of face restoration methods in blind image SR and achieving flexibility on image-specific degradations, we have designed our", + "bbox": [ + 100, + 804, + 470, + 844 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "MetaF2N using the model-agnostic meta-learning framework (MAML) [11]. In this section, we briefly introduce the meta-learning framework based on MAML, which will be helpful for understanding our method.", + "bbox": [ + 497, + 148, + 868, + 200 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Typically, a deep model $f$ is trained by a learning objective $\\mathcal{L}$ , which is directly dependent on the purpose of the task (e.g., $\\ell_1$ loss for fidelity in image SR tasks), and the optimal parameter $\\theta^*$ is obtained via", + "bbox": [ + 497, + 200, + 868, + 252 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\theta^ {*} = \\arg \\min _ {\\theta} \\mathcal {L} (f (\\mathbf {x}; \\theta), \\mathbf {y}), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 594, + 258, + 867, + 277 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\mathbf{x}$ and $\\mathbf{y}$ are input and ground-truth. Intuitively, the objective of Eqn. (1) is to get a $\\theta$ leading to the lowest $\\mathcal{L}$ .", + "bbox": [ + 497, + 283, + 867, + 309 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Instead, MAML [11] aims to learn a parameter $\\theta^{*}$ , which can be efficiently fine-tuned toward the test sample with one or several steps. Taking the one-step situation as an example, the learning objective can be written as", + "bbox": [ + 497, + 309, + 867, + 361 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\theta^ {*} = \\arg \\min _ {\\theta} \\sum_ {T _ {i} \\sim p (T)} \\mathcal {L} ^ {T _ {i}} \\left(f (\\mathbf {x}; \\theta - \\alpha \\frac {\\partial \\mathcal {L} _ {i n} ^ {T _ {i}}}{\\partial \\theta}), \\mathbf {y}\\right), \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 519, + 366, + 867, + 400 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $p(T),\\mathcal{L}_{in}^{T_i}$ , and $\\alpha$ respectively represent the distribution (or collection) of tasks, the inner loop loss function for the task $T_{i}$ , and learning rate for the inner loop. Here, we can regard $\\theta -\\alpha \\frac{\\partial\\mathcal{L}_{in}^{T_i}}{\\partial\\theta}$ as a whole. Then, similar to Eqn. (1), the objective of Eqn. (2) can be interpreted as to get a $\\theta$ leading to the lowest $\\mathcal{L}^{T_i}$ after one back-propagation step w.r.t. $\\mathcal{L}_{in}^{T_i}$ . In other words, a model trained under the MAML settings can adapt to new domains or tasks with a limited number of fine-tuning steps (i.e., $\\theta -\\alpha \\frac{\\partial\\mathcal{L}_{in}^{T_i}}{\\partial\\theta})$", + "bbox": [ + 497, + 406, + 868, + 535 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4. Method", + "text_level": 1, + "bbox": [ + 499, + 543, + 584, + 555 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this work, we aim to obtain a blind image SR model $f$ which can be efficiently adapted to process the degradation of a real-world low-quality image $\\mathbf{I}_{LR}$ under the guidance of its face regions (denoted by $\\mathbf{I}_{LR}^{\\ominus}$ ) and the faces processed by blind face restoration methods (denoted by $\\mathbf{I}_{BFR}^{\\ominus}$ ).", + "bbox": [ + 497, + 564, + 867, + 630 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Considering the complex and wide-range degradations in real-world low-quality images, we take advantage of MAML to design our method for processing image-specific degradations. Then Eqn. (2) can be rewritten as,", + "bbox": [ + 497, + 630, + 868, + 682 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\theta^ {*} = \\arg \\min _ {\\theta} \\sum_ {T _ {i} \\sim p (T)} \\mathcal {L} ^ {T _ {i}} \\left(f \\left(\\mathbf {I} _ {L R}; \\theta - \\alpha \\frac {\\partial \\mathcal {L} _ {i n} ^ {T _ {i}}}{\\partial \\theta}\\right), \\mathbf {I}\\right), \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 514, + 688, + 867, + 720 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $p(T)$ is the distribution of different degradations, $T_{i}$ is the task for one specific degradation, $\\theta$ is the parameter of $f$ and $\\mathbf{I}$ denotes the ground-truth image. The design of $\\mathcal{L}_{in}^{T_i}$ will be given in Sec. 4.1.", + "bbox": [ + 497, + 726, + 868, + 779 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "4.1. Inner Loop Design", + "text_level": 1, + "bbox": [ + 499, + 785, + 670, + 799 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "One of the key factors of applying MAML [11] to blind image SR tasks is the design of $\\mathcal{L}_{in}^{T_i}$ in Eqn. (3). Specifically, for adapting to the new degradation of an $\\mathbf{I}_{LR}$ , the", + "bbox": [ + 497, + 804, + 868, + 844 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "13035", + "bbox": [ + 465, + 875, + 504, + 885 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/b7ef4561c43c31ea7a84af1464be0e372dac16294c2821e8a554c3a121114ce7.jpg", + "image_caption": [ + "Figure 1: Pipeline of the proposed MetaF2N framework. During inference, the inner loop updates the initial parameter $\\theta$ via a back-propagation step (dotted blue line), and the obtained $\\theta_{n}$ is used to process the whole natural image in the outer loop. For training, the parameter update indeed relies on the gradients of outer loop loss $\\mathcal{L}^{T_i}$ w.r.t. the initial parameter $\\theta$ and the MaskNet parameter $\\theta_{\\mathbf{m}}$ (dotted red line). For easier understanding, the steps of the pipeline (remarked by circled numbers) are introduced in Sec. 4.3. Please refer to Algorithms 1 and 2 for more details about the training and inference process." + ], + "image_footnote": [], + "bbox": [ + 126, + 146, + 845, + 289 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "data for calculating $\\mathcal{L}_{in}^{T_i}$ should have the same distribution as $\\mathbf{I}_{LR}$ . For MAML-based non-blind image SR methods [41, 43], one can construct inner loop data by further down-sampling $\\mathbf{I}_{LR}$ with the known degradation $d$ to get $\\mathbf{I}_{LLR} = d(\\mathbf{I}_{LR})$ . Then assuming the inner loop loss function to be $\\ell_1$ , we can obtain $\\mathcal{L}_{in}^{T_i} = \\| f(\\mathbf{I}_{LLR};\\theta) - \\mathbf{I}_{LR}\\|_1$ . However, for blind image SR, it is almost impossible to get extra image pairs with the same degradation as $\\mathbf{I}_{LR}$ since $d$ is unknown.", + "bbox": [ + 100, + 377, + 473, + 495 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Inspired by ReDegNet [26], which shows that faces can be utilized to extract the degradation representation for the whole image, we directly construct the inner loop data with the face regions. Thanks to the great generalization ability of blind face restoration methods [6,50,57,64], we are able to obtain a pseudo ground-truth for the face regions, which is denoted by $\\mathbf{I}_{BFR}^{\\ominus} = f_{BFR}(\\mathbf{I}_{LR}^{\\ominus};\\theta_{BFR})$ , where $f_{BFR}$ is the blind face restoration model with pre-trained parameter $\\theta_{BFR}$ . In this paper, we follow ReDegNet [26] and adopt GPEN [57] as $f_{BFR}$ . With the low-quality face regions $\\mathbf{I}_{LR}^{\\ominus}$ and the recovered $\\mathbf{I}_{BFR}^{\\ominus}$ , the inner loop loss function can be defined by", + "bbox": [ + 100, + 496, + 473, + 652 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {i n} ^ {T _ {i}} = \\left\\| f \\left(\\mathbf {I} _ {L R} ^ {\\ominus}; \\theta\\right) - \\mathbf {I} _ {B F R} ^ {\\ominus} \\right\\| _ {1}. \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 191, + 663, + 470, + 680 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.2. Adaptive Loss Weighting with MaskNet", + "text_level": 1, + "bbox": [ + 100, + 691, + 423, + 706 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Despite the appealing visual quality of recent blind face restoration methods, there inevitably exist gaps between generated faces $\\mathbf{I}_{BFR}^{\\ominus}$ and ground-truth ones $\\mathbf{I}^{\\ominus}$ . For inaccurate regions, the degradation either explicitly (ReDeg-Net [26]) or implicitly (Our MetaF2N) described by the $(\\mathbf{I}_{LR}^{\\ominus},\\mathbf{I}_{BFR}^{\\ominus})$ pair also deviate from that by $(\\mathbf{I}_{LR}^{\\ominus},\\mathbf{I}^{\\ominus})$ .", + "bbox": [ + 100, + 712, + 470, + 792 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "However, different regions of $\\mathbf{I}_{BFR}^{\\odot}$ are treated equally in Eqn. (4), which will have negative effect on the final results. As a remedy, we propose to predict loss weights adaptively for different regions via a MaskNet. With the weight map", + "bbox": [ + 100, + 792, + 472, + 845 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "m generated by the MaskNet, Eqn. (4) can be rewritten as", + "bbox": [ + 499, + 378, + 860, + 391 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {i n} ^ {T _ {i}} = \\left\\| \\mathbf {m} \\cdot \\left(f \\left(\\mathbf {I} _ {L R} ^ {\\ominus}; \\theta\\right) - \\mathbf {I} _ {B F R} ^ {\\ominus}\\right) \\right\\| _ {1}. \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 569, + 397, + 867, + 414 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Ideally, $\\mathbf{m}$ should be generated from the $(\\mathbf{I}_{BFR}^{\\odot},\\mathbf{I}^{\\odot})$ pair. Unfortunately, $\\mathbf{I}$ is unavailable for test samples, a possible solution is solely predicting from $\\mathbf{I}_{BFR}^{\\odot}$ , yet the improvement is marginal. Analogous to degraded-reference IQA [2, 62] which predicts IQA metrics from (input, output) pairs rather than (output, GT) pairs in full-reference IQA, we predict $\\mathbf{m}$ from the $(\\mathbf{I}_{LR}^{\\odot},\\mathbf{I}_{BFR}^{\\odot})$ pair, i.e.,", + "bbox": [ + 497, + 420, + 868, + 513 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {m} = f _ {\\mathbf {m}} \\left(\\mathbf {I} _ {L R} ^ {\\prime}, \\mathbf {I} _ {B F R} ^ {\\prime}; \\theta_ {\\mathbf {m}}\\right), \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 600, + 517, + 867, + 534 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $f_{\\mathbf{m}}$ is the MaskNet, which is a simple network composed of 8 convolution layers shown in Fig. 2. As further shown in the ablation studies, the degraded-reference solution in Eqn. (6) performs better than solely predicting from $\\mathbf{I}_{BFR}^{\\odot}$ .", + "bbox": [ + 497, + 540, + 868, + 606 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.3. Overall Pipeline and Learning Objective", + "text_level": 1, + "bbox": [ + 499, + 612, + 825, + 625 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "With the inner loop designed in Eqn. (5), we can build the pipeline as shown in Fig. 1. In specific, given a low-quality image $\\mathbf{I}_{LR}$ containing face regions denoted by $\\mathbf{I}_{LR}^{\\ominus}$ , we pass $\\mathbf{I}_{LR}^{\\ominus}$ through the SR network $f$ and obtain the inner loop result $\\mathbf{I}_{SR}^{\\ominus}$ . For a fair comparison against existing methods, we take the model of Real-ESRGAN [53] as the SR network, whose parameter is used to initialize the $\\theta$ in the inner loop. To construct supervision for the inner loop, we use a pre-trained GPEN [57] model, whose parameter is kept fixed in our whole pipeline. Then we can obtain the weight map $\\mathbf{m}$ following Eqn. (6), as well as the inner loop loss $\\mathcal{L}_{in}^{T_i}$ following Eqn. (5), which can be used to generate a temporary parameter $\\theta_{\\mathrm{n}} = \\theta -\\alpha \\frac{\\partial\\mathcal{L}_{in}^{T_i}}{\\partial\\theta}$ for processing the whole natural image in the outer loop, i.e.,", + "bbox": [ + 497, + 631, + 868, + 820 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {I} _ {S R} = f \\left(\\mathbf {I} _ {L R}; \\theta_ {\\mathbf {n}}\\right) = f \\left(\\mathbf {I} _ {L R}; \\theta - \\alpha \\frac {\\partial \\mathcal {L} _ {i n} ^ {T _ {i}}}{\\partial \\theta}\\right) ⑥. \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 544, + 825, + 868, + 846 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "13036", + "bbox": [ + 465, + 875, + 505, + 885 + ], + "page_idx": 3 + }, + { + "type": "code", + "sub_type": "algorithm", + "code_caption": [ + "Algorithm 1: Training Process of MetaF2N" + ], + "code_body": "Input: Distribution of different degradation restoration tasks $p(T)$ High-quality natural image dataset $\\mathcal{D}_{HR}$ High-quality face dataset $\\mathcal{D}_{\\odot}$ Learning rates $\\alpha ,\\beta ,\\gamma ,\\eta$ Output: Model parameter $\\theta ,\\theta_{\\mathbf{m}}$ 1 Initialize $f,D$ with $\\theta ,\\theta_{D}$ from Real-ESRGAN [51] 2 Initialize $f_{BFR}$ with $\\theta_{BFR}$ from GPEN [57] 3 Random initialize $f_{\\mathbf{m}}$ with $\\theta_{\\mathbf{m}}$ 4 for all training steps do 5 Sample batch of tasks $T_{i}\\sim p(T)$ 6 for all $T_{i}$ do 7 Sample images $\\mathbf{I},\\mathbf{I}^{\\odot}$ from $\\mathcal{D}_{\\mathcal{H}\\mathcal{R}}$ and $\\mathcal{D}_{\\odot}$ 8 Create $\\mathbf{I},\\mathbf{I}_{LR},\\mathbf{I}_{LR}^{\\odot}$ of $T_{i}$ 9 $\\mathbf{I}_{BFR}^{\\odot} = f_{BFR}(\\mathbf{I}_{LR}^{\\odot};\\theta_{BFR})$ m $= f_{\\mathrm{m}}(\\mathbf{I}_{LR}^{\\odot},\\mathbf{I}_{BFR}^{\\odot};\\theta_{\\mathrm{m}})$ for 1 step of inner loop do 12 $\\begin{array}{r}\\mathcal{L}_{in}^{T_i} = ||\\mathbf{m}\\cdot (f(\\mathbf{I}_{LR}^{\\odot};\\theta) - \\mathbf{I}_{BFR}^{\\odot})||_1\\\\ \\theta_{\\mathrm{n}}\\gets \\theta -\\alpha \\nabla_{\\theta}\\mathcal{L}_{in}^{T_i}(\\theta) \\end{array}$ end 15 $\\mathbf{I}_{SR} = f(\\mathbf{I}_{LR};\\theta_{\\mathbf{n}})$ 16 $\\mathcal{L}^{T_i}$ is defined as Eqn. (13) 17 $\\mathcal{L}_D^{T_i}$ is defined as Eqn. (11) end 19 $\\theta \\gets \\theta -\\beta \\nabla_{\\theta}\\sum_{T_i\\sim p(T)}\\mathcal{L}^{T_i}$ 20 $\\theta_{\\mathrm{m}}\\gets \\theta_{\\mathrm{m}} - \\gamma \\nabla_{\\theta_{\\mathrm{m}}}\\sum_{T_i\\sim p(T)}\\mathcal{L}^{T_i}$ 21 $\\theta_D\\gets \\theta_D - \\eta \\nabla_{\\theta_D}\\sum_{T_i\\sim p(T)}\\mathcal{L}_D^{T_i}$ 22 end", + "bbox": [ + 105, + 166, + 468, + 545 + ], + "page_idx": 4 + }, + { + "type": "code", + "sub_type": "algorithm", + "code_caption": [ + "Algorithm 2: Inference Process of MetaF2N" + ], + "code_body": "Input: LR test image $\\mathbf{I}_{LR}$ Trained model parameter $\\theta ,\\theta_{\\mathrm{m}}$ Pre-trained GPEN [57] parameter $\\theta_{BFR}$ Fine-tuning steps $n$ and learning rate $\\alpha$ Output: Super-resolved image $\\mathbf{I}_{SR}$ 1 Initialize $f,f_{\\mathbf{m}}$ with $\\theta ,\\theta_{\\mathbf{m}}$ 2 Initialize $f_{BFR}$ with $\\theta_{BFR}$ from GPEN [57] 3 Extract face regions $\\mathbf{I}_{LR}^{\\ominus}$ from $\\mathbf{I}_{LR}$ 4 $\\mathbf{I}_{BFR}^{\\ominus} = f_{BFR}(\\mathbf{I}_{LR}^{\\ominus};\\theta_{BFR})$ 5 $\\mathbf{m} = f_{\\mathbf{m}}(\\mathbf{I}_{LR}^{\\ominus},\\mathbf{I}_{BFR}^{\\ominus};\\theta_{\\mathbf{m}})$ 6 for n steps of inner loop do 7 $\\begin{array}{rl}{\\mathcal{L}_{in}} & {= \\| \\mathbf{m}\\cdot (f(\\mathbf{I}_{LR}^{\\ominus};\\theta) - \\mathbf{I}_{BFR}^{\\ominus})\\| _1}\\\\ {\\theta} & {\\leftarrow \\theta -\\alpha \\nabla_{\\theta}\\mathcal{L}_{in}(\\theta)} \\end{array}$ 8 end 9 end 10 $\\theta_{\\mathbf{n}}\\gets \\theta$ 11 $\\mathbf{I}_{SR} = f(\\mathbf{I}_{LR};\\theta_{\\mathbf{n}})$ 12 return $\\mathbf{I}_{SR}$", + "bbox": [ + 105, + 581, + 468, + 807 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/5bb15bb37c5968ada6f539a3ee404aaac6b6a815ac83fa391f2542df17ada67f.jpg", + "image_caption": [ + "Figure 2: The network structure of MaskNet." + ], + "image_footnote": [], + "bbox": [ + 510, + 144, + 858, + 280 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The above process (as remarked by the circled numbers) describes the pipeline of MetaF2N during inference and the first six steps in the training phase.", + "bbox": [ + 499, + 313, + 867, + 352 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "For training MetaF2N, we also need to calculate the outer loop loss $⑦$ , which is composed of fidelity loss $(\\ell_1)$ , LPIPS loss [60], and GAN loss [13]. In specific, the fidelity loss is", + "bbox": [ + 499, + 352, + 867, + 403 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {1} = \\left\\| \\mathbf {I} _ {S R} - \\mathbf {I} \\right\\| _ {1}, \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 623, + 403, + 867, + 418 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "and the LPIPS loss is defined by", + "bbox": [ + 500, + 422, + 702, + 435 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {L P I P S}} = \\| \\phi (\\mathbf {I} _ {S R}) - \\phi (\\mathbf {I}) \\| _ {2}, \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 589, + 442, + 867, + 458 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\phi$ is the pre-trained AlexNet [24] feature extractor for calculating LPIPS. The adversarial loss follows the setting of Real-ESRGAN [51], which is defined by,", + "bbox": [ + 499, + 465, + 867, + 504 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {a d v}} = - \\mathbb {E} [ \\log (D (\\mathbf {I} _ {S R})) ], \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 598, + 511, + 867, + 527 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where the discriminator $D$ is iteratively trained along with the SR network, i.e.,", + "bbox": [ + 499, + 533, + 867, + 559 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {D} = - \\mathbb {E} [ \\log (D (\\mathbf {I})) - \\log (1 - D (\\mathbf {I} _ {S R})) ]. \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 534, + 567, + 867, + 583 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Note that some works [25,32] have explored training GANs under the meta-learning structure, and all of them update the discriminator loss in both the inner loop and outer loop. However, to accelerate the training process and save memory, we only update the discriminator loss in the outer loop, which also shows satisfactory results.", + "bbox": [ + 499, + 589, + 867, + 667 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To improve the numerical stability and avoid gradient exploding/vanishing, we constrain the MaskNet $f_{\\mathbf{m}}$ via a regularization term, which is defined by", + "bbox": [ + 499, + 667, + 867, + 706 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {r e g}} = \\| \\mathbf {m} - \\mathbf {1} \\| _ {2}. \\tag {12}\n$$\n", + "text_format": "latex", + "bbox": [ + 621, + 714, + 867, + 729 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In summary, the learning objective of our MetaF2N (i.e., the outer loop loss) is", + "bbox": [ + 499, + 735, + 867, + 762 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} ^ {T _ {\\mathrm {i}}} = \\lambda_ {1} \\mathcal {L} _ {1} + \\lambda_ {2} \\mathcal {L} _ {\\text {L P I I P S}} + \\lambda_ {3} \\mathcal {L} _ {\\text {a d v}} + \\lambda_ {4} \\mathcal {L} _ {\\text {r e g}}, \\tag {13}\n$$\n", + "text_format": "latex", + "bbox": [ + 522, + 769, + 867, + 785 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where the hyperparameters $\\lambda_1, \\lambda_2, \\lambda_3$ , and $\\lambda_4$ are empirically set to 1, 0.5, 0.1, and 0.002, respectively. Please refer to Algorithms 1 and 2 for more details on the training and inference process of the proposed MetaF2N.", + "bbox": [ + 499, + 790, + 867, + 844 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "13037", + "bbox": [ + 465, + 875, + 504, + 885 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 102, + 147, + 226, + 161 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.1. Dataset and Training Details", + "text_level": 1, + "bbox": [ + 102, + 168, + 342, + 182 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Training Data. For synthesizing data to train the proposed MetaF2N, high-quality facial and natural images are required for inner and outer loop, respectively. It is worth noting that, the requirement on the training data is that $\\mathbf{I}_{LR}^{\\odot}$ and $\\mathbf{I}_{LR}$ share the identical degradation, but they are not necessarily from the same image. Therefore, to better leverage existing high-quality facial and natural image datasets, we use the first 30,000 images of the aligned FFHQ [21] dataset for the inner loop, and adopt DF2K1 with 3,450 images in total for the outer loop following recent blind image SR methods [26, 51, 59]. For a fair comparison against other methods, we follow the degradation setting of RealESRGAN [51] for low-quality image synthesis. More details are given in the supplementary material.", + "bbox": [ + 100, + 188, + 473, + 371 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Testing Data. To comprehensively evaluate the proposed MetaF2N, we have constructed several testing datasets.", + "bbox": [ + 100, + 376, + 472, + 402 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Synthetic datasets are built upon the in-the-wild version of FFHQ [21] and CelebA [34], where 1,000 high-quality images are extracted from each dataset, and faces occupy around $10\\%$ areas of the whole image on average. With the high-quality images, we first construct two test datasets whose degradations are independent and identically distributed as the training set, which are denoted by $\\mathrm{FFHQ}_{iid}$ and $\\mathrm{CelebA}_{iid}$ , respectively. For evaluating the generalization ability on out-of-distribution degradations, we further construct $\\mathrm{FFHQ}_{ood}$ and $\\mathrm{CelebA}_{ood}$ by changing the parameters of the degradation model, e.g., Gaussian blur $\\rightarrow$ motion blur, Gaussian/Poisson noise $\\rightarrow$ Speckle noise. The detailed parameters are in the supplementary material.", + "bbox": [ + 100, + 403, + 473, + 571 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "A real-world dataset RealFaces200 (RF200) is also established for evaluation under a real scenario, which contains 200 real-world low-quality images collected from the Internet or existing datasets (e.g., WIDER FACE [56]), and there are one or multiple faces in each image.", + "bbox": [ + 100, + 572, + 472, + 637 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Implementation Details. The proposed MetaF2N mainly focuses on leveraging meta-learning for efficient model adaptation for blind image SR, which is independent of network architecture and can be incorporated into arbitrary second-order differentiable models. Therefore, we follow Real-ESRGAN [51], BSRGAN [59], and ReDegNet [26] to adopt the architecture of ESRGAN [53]. For training, each image is cropped into patches, and the patch size is $128 \\times 128$ for the inner loop (i.e., $\\mathbf{I}_{LR}^{\\ominus}$ , $\\mathbf{I}_{BFR}^{\\ominus}$ , and $\\mathbf{I}_{SR}^{\\ominus}$ ) and $256 \\times 256$ for the outer loop (i.e., $\\mathbf{I}_{LR}$ , $\\mathbf{I}_{SR}$ , and $\\mathbf{I}$ ). The Adam [23] optimizer with $\\beta_{1} = 0.5$ and $\\beta_{2} = 0.999$ is adopted. For the SR model $f$ , the learning rate (lr) of the inner and outer loops are $1 \\times 10^{-2}$ and $3 \\times 10^{-5}$ , respectively, while the lr for the discriminator and MaskNet are $1 \\times 10^{-4}$ .", + "bbox": [ + 100, + 642, + 473, + 824 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The MetaF2N is trained for one week and all experiments are conducted on a server with one RTX A6000 GPU.", + "bbox": [ + 499, + 148, + 868, + 173 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.2. Comparison with State-of-the-art Methods", + "text_level": 1, + "bbox": [ + 499, + 182, + 842, + 195 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To show the effectiveness of the proposed MetaF2N, we compare with several state-of-the-art blind image SR methods, including ESRGAN [53], RealSR [5], Real-ESRGAN [51], BSRGAN [59], MM-RealSR [39], and RedegNet [26]. For quantitative evaluation, we utilize PSNR, LPIPS [60], FID [17], and NIQE [38] for synthetic datasets. As for the real-world dataset, since no ground-truth is available, PSNR and LPIPS are omitted. It is worth noting that KID is more accurate and appropriate than FID when evaluating the quality of images with a smaller amount of samples [3]. Thus we use KID [3] and NIQE [38] for quantitative evaluation on our RF200 dataset. To accurately calculate the distance between SR results and real-world high-quality images (i.e., FID and KID), we construct these types of reference images following [4], which estimates a blurriness score based on the total variance of the Laplacian of an image. Finally, 3,808 high-quality images are selected from the in-the-wild version of FFHQ [21], whose scores are higher than the threshold defined in [4].", + "bbox": [ + 497, + 201, + 868, + 450 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Quantitative Comparison. The quantitative evaluation results are provided in Tabs. 1 and 2. We provide three results of our Meta-F2N, i.e., Ours (1), Ours (10), and Ours (20), where the number in the parentheses denotes the amount of fine-tuning steps during inference. All three models are initialized with the same parameter $\\theta$ . For the degradations independent and identically distributed as the training set (i.e., $\\mathrm{FFHQ}_{iid}$ and CelebA $_{iid}$ ), our MetaF2N can achieve superior performance on LPIPS, FID, and NIQE with only one fine-tuning step, and can surpass most of the competing methods on PSNR. Besides, with more fine-tuning iterations, the image quality can be further enhanced. For out-of-distribution degradations in Tab. 2 (i.e., $\\mathrm{FFHQ}_{ood}$ , CelebA $_{ood}$ , and RF200), the trends are similar to Tab. 1, and our MetaF2N again outperforms others on most metrics, especially on the real-world RF200 dataset.", + "bbox": [ + 497, + 454, + 868, + 661 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "As for the competing methods, ESRGAN [53] and RealSR [5] are trained with simple degradation models, which lead to unsatisfactory performance under more complex and realistic degradations. Real-ESRGAN [51], BSRGAN [59], MM-RealSR [39], and ReDegNet [26] leverage more realistic degradation models or even real-world degradations, which contribute to much better results, yet their performance is still limited by the deterministic model and fixed degradation range. Furthermore, we also fine-tune ReDegNet [26] on RF200, and the results are provided in Tab. 2 (ReDegNet†). Compared to MetaF2N that achieves decent performance with only one fine-tuning step, marginal improvements are observed on NIQE even the ReDegNet [26] is carefully fine-tuned hundreds iterations for each image.", + "bbox": [ + 497, + 662, + 868, + 844 + ], + "page_idx": 5 + }, + { + "type": "page_footnote", + "text": "$^{1}$ DF2K is the combination of DIV2K [1] and Flickr2K [46] datasets.", + "bbox": [ + 119, + 831, + 460, + 844 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "13038", + "bbox": [ + 465, + 875, + 505, + 885 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/c8ca386e0de2c3584d6ca12fed7abdb22a5e99a53e26980e183ae0c122e96194.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 129, + 146, + 230, + 194 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/f3b31ca2fab7c3471e2a9ad48e47187e1b144eaf6b8d9b5199ff366af8034270.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 129, + 195, + 230, + 285 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/2d9e97d33919ac8efb54dd80671c9574c4c72b5cc9fcd71c9e60b90d6e94462a.jpg", + "image_caption": [ + "Synthetic LR" + ], + "image_footnote": [], + "bbox": [ + 129, + 286, + 230, + 339 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/2bd392cc1e47a22b82973331f50e847117f6f7a80c6735f067eb0c2f85f32df9.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 231, + 146, + 332, + 194 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/292ea930cf1604bdf0fbb5a971edaddfbfe9096750effb6c8f0544b5b90efa0a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 231, + 195, + 332, + 285 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/f1e75c7d0e59e466e7ad140ea5e9c3dc788e8bee02cc885edcc2bfe7d899b600.jpg", + "image_caption": [ + "Real-ESRGAN [51]" + ], + "image_footnote": [], + "bbox": [ + 231, + 286, + 332, + 339 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/0c02920714760cde53e52f10961386449a98e208622d08bbf1513c083b2c004b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 332, + 146, + 433, + 194 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/e6dc186542afe93de71dde448aaf69b1f4a80ac63a53d1c8d99129103cc58321.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 332, + 195, + 433, + 285 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/99ba1bdcef4e921812ba41bf73752c5273244211158136940ff7f510c311c448.jpg", + "image_caption": [ + "BSRGAN [59]" + ], + "image_footnote": [], + "bbox": [ + 332, + 286, + 433, + 339 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/74d460472d7bf866569be3e53cab3a9c43d14e7e16d1446fb38ea6db3b49df9b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 435, + 146, + 534, + 194 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/70d3b07a36f62d2f31f99596c686658cb43f2da55da5e52747478d34651b4455.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 435, + 195, + 536, + 285 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/0541b81921d249d49026ccb8080bf4198eff49a84b67bbe5b0df49f787e425bb.jpg", + "image_caption": [ + "MM-RealSR [39]" + ], + "image_footnote": [], + "bbox": [ + 435, + 286, + 536, + 339 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/abb288e6bda4880caa82cb1774933f7082f0ce575766f9cb6052c58a9341392b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 536, + 146, + 636, + 194 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/15021f1bf6a6c95c7c2ac93c12ad1d3e6ea94924f5267e257a8cd93575a30536.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 536, + 195, + 636, + 285 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/b837f5e322ecc33faf7ea74ef87fe4522141f97100dac29b949ba2d8aa67fccc.jpg", + "image_caption": [ + "ReDegNet [26]" + ], + "image_footnote": [], + "bbox": [ + 536, + 286, + 636, + 339 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/29b72e2f104a64ee8702acb7911cac1c4452e02489f014291fd7ae704c5a9bed.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 638, + 146, + 739, + 194 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/dc81b3f8f3c8b473713d69035fb81c6be0939d527a069e6d7240ad5819e3c1dd.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 638, + 195, + 739, + 285 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/984046f723fff7f99e07838ed578a16058eadb2afdc9f7e5d5008264bba39709.jpg", + "image_caption": [ + "Ours" + ], + "image_footnote": [], + "bbox": [ + 638, + 286, + 739, + 339 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/f21d224c7d56e794af53dceb6ee7449430fb802b184c84631c58b11260d4ebe7.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 739, + 146, + 840, + 194 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/33eade57d93a7503b3bf9362dea39b9b4699c7fdcdece28ff0fc98cdb59485c7.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 739, + 195, + 840, + 285 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/db61604dff7829b6f647b07f718ba3be647a77fdc95ec20440157f1ba39e1a60.jpg", + "image_caption": [ + "Ground-truth" + ], + "image_footnote": [], + "bbox": [ + 739, + 286, + 840, + 339 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/90797db8f37ca3f626263e3467c025a3b6daf24d4c7027243aa172e4a34ee365.jpg", + "image_caption": [ + "Figure 3: Visual comparison against state-of-the-art blind SR methods on synthetic datasets. Note that the results of Ours are produced by MetaF2N with one-step fine-tuning. Please zoom in for better observation." + ], + "image_footnote": [], + "bbox": [ + 129, + 382, + 230, + 441 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/8477c94867bccef0f2e092a06bc95edd49225d2567fd0b119ad2d5488eda1b83.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 129, + 442, + 230, + 511 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/a3a12e5762cf3f501334faf7e58216bcbe1e5fba9bbe0a5e742b6cd231caab11.jpg", + "image_caption": [ + "Real-world LR", + "Figure 4: Visual comparison against state-of-the-art blind SR methods on real-world low-quality images in our RF200 dataset. ReDegNet† means that model is fine-tuned for each image following the official configurations of ReDegNet [26]." + ], + "image_footnote": [], + "bbox": [ + 129, + 511, + 230, + 610 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/d8ae5eb836c1a586985c8c205d978e5dd1dcc76b382a24c62ca6b99aecf71bc8.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 231, + 382, + 332, + 441 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c22bcdd62f1d5e267cdac7e4b9830f84f84c8318399d8da4075fb88eff8d7bb9.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 231, + 442, + 332, + 511 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1091e6238610d5240f91ff921d3aac814380fef45bb2463a90568c9b5ff0c93e.jpg", + "image_caption": [ + "Real-ESRGAN [51]" + ], + "image_footnote": [], + "bbox": [ + 231, + 511, + 332, + 610 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/29917520a90e722128280dfb2f62f71a86570122f15fbb7f5d80399b9bb91edc.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 332, + 382, + 433, + 441 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/f090cb66ca59e509a787d5b78ea8e38d6b8c8345091309f1735ccb4d5e8714d5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 332, + 442, + 433, + 511 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/bd396fc02925daaa1bf24073e85323d895aa360e1a3204094127a9eecbf93f6a.jpg", + "image_caption": [ + "BSRGAN [59]" + ], + "image_footnote": [], + "bbox": [ + 332, + 511, + 433, + 610 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/48a60a266aa0fb4ec000bb1d0b7380d1fa2aa70779e06f8e87762b7dab5bb45a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 435, + 382, + 534, + 441 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1fec9269dc52275437abfd001bcace5e3a5142b5673311195a67d3bd11dbd92f.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 435, + 442, + 536, + 511 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/dc200565769a18bb3bc6c3436f274ae9a4c3fbdaddd46d6c1929258f9d164c20.jpg", + "image_caption": [ + "MM-RealSR [39]" + ], + "image_footnote": [], + "bbox": [ + 435, + 511, + 536, + 610 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/a1a4554caed9fb7c9177b1eb295a29a852856fb04428acf3723be79ba89ae773.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 536, + 382, + 636, + 441 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/68e8ab179dfa3fe19d8c7a877a2652150cc019b89928efaf5cce42433e3302d2.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 536, + 442, + 636, + 511 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/b9eafe7835425c64b34aa7655334e57538466b56badae1db2ca7b8eeefb50a45.jpg", + "image_caption": [ + "ReDegNet [26]" + ], + "image_footnote": [], + "bbox": [ + 536, + 511, + 636, + 610 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/8fe645a0101fc0c3cb776d937913870ab102bb3052df6f9d34f9b79f8bb53f6c.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 638, + 382, + 739, + 441 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/a6f9d6da8d1977ee9caf0f43ffa941159927cbb3933052f7ba235d6382d52ee0.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 638, + 442, + 739, + 511 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/67566032ef532b513c75c788940df48b7da70161d2283de9677eb48ec3f6bf3d.jpg", + "image_caption": [ + "ReDegNet [26]" + ], + "image_footnote": [], + "bbox": [ + 638, + 511, + 739, + 610 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/08faeaf42b6832cd8a3a0e2783482caadddb568d696121cb1d342d7f0f86551d.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 739, + 382, + 840, + 441 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1d0872bcbeb1cd4a6bdfcc69f175d8f45376aee4121df3f9304f864d0419c765.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 739, + 442, + 840, + 511 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/3709756ab95397b548fd4a3ec2724dca4b10000d6a5322fda6e7d223126e26ab.jpg", + "image_caption": [ + "Ours" + ], + "image_footnote": [], + "bbox": [ + 739, + 511, + 840, + 610 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Qualitative Comparison. Apart from the quantitative comparison, we also compare our MetaF2N with state-of-the-art blind image SR methods qualitatively. Due to the space limit, we show the results generated by Ours (1), which is fine-tuned for 1 step with the face regions, and more qualitative results (including those generated by Ours (10) and Ours (20)) are provided in the supplementary material. As shown in Figs. 3 and 4, our results are much clearer and contain more photo-realistic textures, which can be ascribed to the effectiveness of our image-specific fine-tuning scheme.", + "bbox": [ + 100, + 661, + 472, + 790 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.3. The Visual Results of MaskNet", + "text_level": 1, + "bbox": [ + 102, + 798, + 359, + 809 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "To better explain the effect of our MaskNet, we calculate the error map $EM$ between ground-truth faces $\\mathbf{I}^{\\odot}$ and", + "bbox": [ + 100, + 817, + 470, + 844 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "GPEN [57] generated faces $\\mathbf{I}_{BFR}^{\\odot}$ directly through subtraction and normalization, i.e.,", + "bbox": [ + 499, + 661, + 867, + 687 + ], + "page_idx": 6 + }, + { + "type": "equation", + "text": "\n$$\nE M = \\frac {\\left| \\mathbf {I} ^ {\\ominus} - \\mathbf {I} _ {B F R} ^ {\\ominus} \\right|}{\\operatorname* {m a x} \\left(\\left| \\mathbf {I} ^ {\\ominus} - \\mathbf {I} _ {B F R} ^ {\\ominus} \\right|\\right)}. \\tag {14}\n$$\n", + "text_format": "latex", + "bbox": [ + 594, + 692, + 867, + 723 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In Fig. 5, we show the predicted $\\mathbf{m}$ and $1 - EM$ . One can see that the predicted $\\mathbf{m}$ follows similar distribution to $1 - EM$ , indicating that our MaskNet has the ability to predict the gap between generated faces and real ones, which benefits the blind image SR performance. Besides, the predicted $\\mathbf{m}$ is smoother than $1 - EM$ , due to that 1) $\\mathbf{m}$ is predicted from $(\\mathbf{I}_{LR}^{\\ominus}$ and $\\mathbf{I}_{BFR}^{\\ominus})$ , which lead to less accurate results, and 2) a regularization term $\\mathcal{L}_{\\mathrm{reg}} = \\| \\mathbf{m} - 1\\|_2$ is applied to constrain $\\mathbf{m}$ not to deviate too far from 1.", + "bbox": [ + 497, + 726, + 868, + 844 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "13039", + "bbox": [ + 465, + 875, + 505, + 885 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/18880d4c2e7aef0eb52d8027194ec333c21ec2c9496c78678aa30dc59ced71da.jpg", + "table_caption": [ + "Table 1: Quantitative comparison on synthetic datasets with independent and identically distributed degradations as the training set. We also show the datasets used for training each method. Note that RealFaces used by ReDegNet [26] consists of 10,000 real-world low-quality face images collected by the authors. The numbers in the parentheses are the image-specific fine-tuning steps of our MetaF2N during inference. The best and second-best results are highlighted by bold and underline." + ], + "table_footnote": [], + "table_body": "
MethodsTraining SetFFHQiiidCelebAiid
PSNR↑LPIPS↓FID↓NIQE↓PSNR↑LPIPS↓FID↓NIQE↓
ESRGAN [53]DF2K [1,46], OST [52]25.100.642123.677.5624.780.55599.106.27
RealSR [19]DF2K [1,46]25.390.597122.237.5924.740.54999.465.77
Real-ESRGAN [51]DF2K [1,46], OST [52]26.350.29350.704.8525.810.31151.695.00
BSRGAN [59]DF2K [1,46], FFFHQ [21], WED [35]26.270.30550.984.6325.860.30950.054.83
MM-RealSR [39]DF2K [1,46], OST [52]25.390.29550.834.5824.940.31152.304.76
ReDegNet [26]DF2K [1,46], FFFHQ [21], RealFaces25.640.30957.044.7925.170.32956.844.94
Ours (1)DF2K [1,46], FFFHQ [21]26.130.28144.943.8125.630.28945.723.97
Ours (10)DF2K [1,46], FFFHQ [21]26.220.28044.943.8725.700.28945.434.03
Ours (20)DF2K [1,46], FFFHQ [21]26.300.27944.513.9425.760.28945.224.10
", + "bbox": [ + 137, + 205, + 828, + 347 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/70c2646c244837b0950266fbaead4c00f933c1812b87ef9e337d25770e59fd16.jpg", + "table_caption": [ + "Table 2: Quantitative comparison on synthetic datasets with out-of-distribution degradations and the collected real-world dataset RF200. ReDegNet† means that model is fine-tuned for each image following the official configurations of ReDeg-Net [26]. The numbers in the parentheses are the image-specific fine-tuning steps of our MetaF2N during inference. The best and second-best results are highlighted by bold and underline." + ], + "table_footnote": [], + "table_body": "
MethodsFFHQoodCelebAoodRF200
PSNR↑LPIPS↓FID↓NIQE↓PSNR↑LPIPS↓FID↓NIQE↓KID↓NIQE↓
ESRGAN [53]24.690.659101.436.9424.070.56787.615.6421.85.32
RealSR [19]24.910.58797.426.3323.980.56790.305.5121.95.00
Real-ESRGAN [51]25.730.30247.875.3425.070.32248.775.4322.43.82
BSRGAN [59]25.730.29846.404.7825.330.31348.124.9122.14.11
MM-RealSR [39]25.030.29747.304.9924.410.31748.765.1022.14.12
ReDegNet [26]25.540.30448.475.0924.760.33152.335.2823.54.07
ReDegNet†[26]--------23.83.56
Ours (1)25.490.28445.074.2224.870.29747.034.3221.23.03
Ours (10)25.570.28444.644.3024.930.29746.504.3921.03.08
Ours (20)25.650.28344.304.3625.000.29746.234.4720.83.12
", + "bbox": [ + 200, + 412, + 769, + 567 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4. Ablation Studies", + "text_level": 1, + "bbox": [ + 102, + 584, + 255, + 598 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "To verify the effectiveness of the components of the proposed MetaF2N, we have also conducted several ablation studies. Without loss of generality, all ablation studies are performed with $\\mathrm{FFHQ}_{i id}$ based on Ours (1). Due to the space limit, qualitative results of ablation studies are given in the supplementary material.", + "bbox": [ + 100, + 604, + 470, + 682 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "MaskNet Configuration. To show the effectiveness of the MaskNet, we train a variant of our MetaF2N by removing the MaskNet. Besides, as introduced in Sec. 1, we design the MaskNet inspired by degraded-reference IQA methods, which takes both low-quality and restored faces as input (denoted by $\\mathrm{MaskNet}_{DR}$ ). For verifying the design, we also consider another variant of MetaF2N which utilizes the non-reference scheme, i.e., only the restored face is taken by the MaskNet (denoted by $\\mathrm{MaskNet}_{NR}$ ). As shown in Tab. 3, the deployment of MaskNet brings considerable improvements, and utilizing the low-quality face image as a reference is also useful for our task.", + "bbox": [ + 100, + 687, + 473, + 844 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Training Data Configuration. Since ground-truth faces are available during training, we train another variant by using the ground-truth face image as the inner loop supervision. Note that the MaskNet is trained together with the SR model, and we omitted it when training the version using ground-truth faces as inner loop supervision since the optimal solution should be an all-one mask. As shown in Tab. 3, the performance decreases by a large margin compared to MetaF2N, which is attributed to the gaps in the inner loop supervision between the training and inference phases.", + "bbox": [ + 497, + 584, + 868, + 717 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Inner Loop Supervision Scheme. Since there are often multiple faces in a single image, as a natural extension of our method, it is intuitive to apply multiple faces to stabilize the fine-tuning process. Therefore, we also explore the inner loop supervision scheme based on another 1,000 images sampled from the in-the-wild version of FFHQ [21] with multiple faces. As shown in Tab. 4, using patches of multiple faces can slightly benefit the final performance.", + "bbox": [ + 497, + 720, + 870, + 826 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Influence of Different Face Hallucination Network. To", + "bbox": [ + 500, + 831, + 870, + 844 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "13040", + "bbox": [ + 465, + 875, + 505, + 885 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/5547abbf98f572c9575eed8c353976212af4198d644908cbd849dcf27353b6cb.jpg", + "image_caption": [ + "Figure 5: Visual results of MaskNet." + ], + "image_footnote": [], + "bbox": [ + 115, + 144, + 458, + 528 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "find the influence of different face hallucination network for the MetaF2N, we conduct an ablation study by replacing GPEN [57] with CodeFormer [63] during training and testing. As shown in Tab. 5, one can see that our MetaF2N shows satisfactory robustness with different face hallucination networks for both $\\mathrm{FFHQ}_{i\\bar{i}d}$ and $\\mathrm{FFHQ}_{\\mathrm{ood}}$ . Although the CodeFormer [63] can restore higher quality faces compared with GPEN [57], our MaskNet minish the gap through allocating weights for each pixel of restored faces, which enhances the robustness of MetaF2N for different face hallucination networks.", + "bbox": [ + 100, + 551, + 472, + 694 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Table 3: Ablation study on the training scheme regarding data configuration and the MaskNet. Train/Test Faces denote the setting of inner-loop supervision during the training and inference stages.", + "bbox": [ + 100, + 707, + 470, + 761 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/521cc3022f4f2c5fb71764b8d96cb4fbfbb9fbee73895a27d741ec7289ddd06c.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MaskNetTrain FacesTest FacesPSNR↑LPIPS↓FID↓NIQE↓
-GTGPEN25.680.28546.964.08
-GPENGPEN26.170.28447.894.21
MaskNetNRGPENGPEN26.070.28447.974.09
MaskNetDRGPENGPEN26.130.28145.223.81
", + "bbox": [ + 107, + 763, + 467, + 838 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/e2e376dfb6d52377b020b6fe06f5bbf02d48277a6c7e565b40206ebfac50ad64.jpg", + "table_caption": [ + "Table 4: Ablation study on inner loop supervision, which is performed on 1,000 images with multiple faces ( $\\sim$ 2.3 faces/image) from the in-the-wild version of FFHQ [21]." + ], + "table_footnote": [], + "table_body": "
# of FacesData FormPSNR↑LPIPS↓FID↓NIQE↓
SingleFull image25.730.28842.963.63
Single32 patches25.770.28842.893.65
Multiple32 patches in total25.790.28742.853.65
Multiple32 patches per face25.790.28742.813.65
", + "bbox": [ + 507, + 191, + 858, + 270 + ], + "page_idx": 8 + }, + { + "type": "table", + "img_path": "images/1b02c90001273f05c9b394878c716b11c859c103ae6f964d1e9a2d384dc822df.jpg", + "table_caption": [ + "Table 5: Ablation study on face hallucination networks which is performed on both $\\mathrm{FFHQ}_{iid}$ and $\\mathrm{FFHQ}_{ood}$ ." + ], + "table_footnote": [], + "table_body": "
TestsetsTrain FacesTest FacesPSNR↑LPIPS↓FID↓NIQE↓
FFHQidGPENGPEN26.130.28145.223.81
CodeFormerCodeFormer26.100.27845.833.83
FFHQoodGPENGPEN25.490.28445.074.22
CodeFormerCodeFormer25.510.28144.584.24
", + "bbox": [ + 504, + 307, + 868, + 389 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5.5. Limitations and Future Work", + "text_level": 1, + "bbox": [ + 499, + 410, + 747, + 425 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Since our MetaF2N is trained in a MAML framework, the performance before fine-tuning is unconstrained. As such, our model requires fine-tuning with the contained faces for one or multiple steps, making it cannot be directly applied if no faces exist in real-world low-quality images, which limits the application scenarios of our method. In the future, we plan to solve this problem by collecting a real-world low-quality training set and providing a better initialization of parameters that can be used to achieve satisfactory performance even without fine-tuning.", + "bbox": [ + 497, + 433, + 868, + 565 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 499, + 581, + 610, + 596 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this paper, we proposed a MetaF2N framework for face-guided blind image SR. The MetaF2N improves the practicability of leveraging blind face restoration for processing image-specific degradations. A MaskNet is deployed to predict the loss weights for different positions considering the gaps between recovered faces and potential ground-truth ones. The proposed MetaF2N achieves superior performance on synthetic datasets with both independent and identically distributed and out-of-distribution degradations compared to training sets. The effectiveness is also validated on the collected real-world dataset.", + "bbox": [ + 497, + 606, + 868, + 749 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Acknowledgement", + "text_level": 1, + "bbox": [ + 500, + 767, + 650, + 783 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work was supported in part by the National Key Research and Development Program of China under Grant No. 2022YFA1004103 and the National Natural Science Foundation of China (NSFC) under Grant No. U19A2073.", + "bbox": [ + 497, + 790, + 868, + 844 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "13041", + "bbox": [ + 465, + 875, + 504, + 885 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 104, + 146, + 193, + 160 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Eirikur Agustsson and Radu Timofte. NTIRE 2017 challenge on single image super-resolution: Dataset and study. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 126-135, 2017. 6, 8", + "[2] Shahrukh Athar and Zhou Wang. Degraded reference image quality assessment. IEEE Transactions on Image Processing, pages 822-837, 2023. 2, 4", + "[3] Mikołaj Binkowski, Danica J Sutherland, Michael Arbel, and Arthur Gretton. Demystifying mmd gans. In International Conference on Learning Representations, pages 1-36, 2018. 6", + "[4] Will Brennan. BlurDetection2. https://github.com/WillBrennan/BlurDetection2, 2017.6", + "[5] Jianrui Cai, Hui Zeng, Hongwei Yong, Zisheng Cao, and Lei Zhang. Toward real-world single image super-resolution: A new benchmark and a new model. In IEEE International Conference on Computer Vision, pages 3086-3095, 2019. 1, 2, 6", + "[6] Kelvin CK Chan, Xintao Wang, Xiangyu Xu, Jinwei Gu, and Chen Change Loy. GLEAN: Generative latent bank for large-factor image super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 14245-14254, 2021. 3, 4", + "[7] Chaofeng Chen, Xiaoming Li, Lingbo Yang, Xianhui Lin, Lei Zhang, and Kwan-Yee K Wong. Progressive semantic-aware style transformation for blind face restoration. In IEEE Conference on Computer Vision and Pattern Recognition, pages 11896-11905, 2021. 3", + "[8] Chang Chen, Zhiwei Xiong, Xinmei Tian, Zheng-Jun Zha, and Feng Wu. Camera lens super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 1652-1660, 2019. 1, 2", + "[9] Honggang Chen, Xiaohai He, Linbo Qing, Yuanyuan Wu, Chao Ren, Ray E Sheriff, and Ce Zhu. Real-world single image super-resolution: A brief review. Information Fusion, pages 124-145, 2022. 1, 2", + "[10] Mohammad Emad, Maurice Peemen, and Henk Corporaal. DualSR: Zero-shot dual learning for real-world superresolution. In IEEE Winter Conference on Applications of Computer Vision, pages 1630-1639, 2021. 1", + "[11] Chelsea Finn, Pieter Abbeel, and Sergey Levine. Model-agnostic meta-learning for fast adaptation of deep networks. In International Conference on Machine Learning, pages 1126–1135, 2017. 2, 3", + "[12] Manuel Fritsche, Shuhang Gu, and Radu Timofte. Frequency separation for real-world super-resolution. In IEEE International Conference on Computer Vision Workshops, pages 3599-3608, 2019. 2", + "[13] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. Communications of the ACM, pages 139–144, 2020. 5", + "[14] Erin Grant, Chelsea Finn, Sergey Levine, Trevor Darrell, and Thomas Griffiths. Recasting gradient-based meta-learning as hierarchical bayes. arXiv preprint arXiv:1801.08930, 2018. 3" + ], + "bbox": [ + 105, + 168, + 470, + 842 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[15] Jinjin Gu, Hannan Lu, Wangmeng Zuo, and Chao Dong. Blind super-resolution with iterative kernel correction. In IEEE Conference on Computer Vision and Pattern Recognition, pages 1604-1613, 2019. 2", + "[16] Yuchao Gu, Xintao Wang, Liangbin Xie, Chao Dong, Gen Li, Ying Shan, and Ming-Ming Cheng. VQFR: Blind face restoration with vector-quantized dictionary and parallel decoder. In European Conference on Computer Vision, pages 126–143, 2022. 3", + "[17] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in Neural Information Processing Systems, pages 6626-6637, 2017. 6", + "[18] Yan Huang, Shang Li, Liang Wang, Tieniu Tan, et al. Unfolding the alternating optimization for blind super resolution. Advances in Neural Information Processing Systems, pages 5632-5643, 2020. 2", + "[19] Xiaozhong Ji, Yun Cao, Ying Tai, Chengjie Wang, Jilin Li, and Feiyue Huang. Real-world super-resolution via kernel estimation and noise injection. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 466-467, 2020. 2, 8", + "[20] Hamid Reza Vaezi Joze, Ilya Zharkov, Karlton Powell, Carl Ringler, Luming Liang, Andy Roulston, Moshe Lutz, and Vivek Pradeep. ImagePairs: Realistic super resolution dataset via beam splitter camera rig. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 518-519, 2020. 2", + "[21] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In IEEE Conference on Computer Vision and Pattern Recognition, pages 4401-4410, 2019. 2, 6, 8, 9", + "[22] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of stylegan. In IEEE Conference on Computer Vision and Pattern Recognition, pages 8110-8119, 2020. 3", + "[23] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. 6", + "[24] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E Hinton. Imagenet classification with deep convolutional neural networks. Communications of the ACM, pages 84-90, 2017. 5", + "[25] Royson Lee, Rui Li, Stylianos I Venieris, Timothy Hospedales, Ferenc Huszár, and Nicholas D Lane. Metalearned kernel for blind super-resolution kernel estimation. arXiv preprint arXiv:2212.07886, 2022. 3, 5", + "[26] Xiaoming Li, Chaofeng Chen, Xianhui Lin, Wangmeng Zuo, and Lei Zhang. From face to natural image: Learning real degradation for blind image super-resolution. In European Conference on Computer Vision, pages 376-392, 2022. 1, 3, 4, 6, 7, 8", + "[27] Xiaoming Li, Chaofeng Chen, Shangchen Zhou, Xianhui Lin, Wangmeng Zuo, and Lei Zhang. Blind face restoration via deep multi-scale component dictionaries. In European Conference on Computer Vision, pages 399-415, 2020. 3" + ], + "bbox": [ + 502, + 149, + 868, + 844 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "13042", + "bbox": [ + 465, + 875, + 505, + 885 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[28] Xiaoming Li, Wenyu Li, Dongwei Ren, Hongzhi Zhang, Meng Wang, and Wangmeng Zuo. Enhanced blind face restoration with multi-exemplar images and adaptive spatial feature fusion. In IEEE Conference on Computer Vision and Pattern Recognition, pages 2706-2715, 2020. 3", + "[29] Xiaoming Li, Ming Liu, Yuting Ye, Wangmeng Zuo, Liang Lin, and Ruigang Yang. Learning warped guidance for blind face restoration. In European Conference on Computer Vision, pages 272-289, 2018. 3", + "[30] Xiaoming Li, Shiguang Zhang, Shangchen Zhou, Lei Zhang, and Wangmeng Zuo. Learning dual memory dictionaries for blind face restoration. IEEE Transactions on Pattern Analysis and Machine Intelligence, pages 1-13, 2022. 3", + "[31] Xiaoming Li, Wangmeng Zuo, and Chen Change Loy. Learning generative structure prior for blind text image super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 10103-10113, 2023. 3", + "[32] Weixin Liang, Zixuan Liu, and Can Liu. Dawson: A domain adaptive few shot generation framework. arXiv preprint arXiv:2001.00576, 2020. 5", + "[33] Anran Liu, Yihao Liu, Jinjin Gu, Yu Qiao, and Chao Dong. Blind image super-resolution: A survey and beyond. IEEE Transactions on Pattern Analysis and Machine Intelligence, pages 1-19, 2022. 1, 2", + "[34] Ziwei Liu, Ping Luo, Xiaogang Wang, and Xiaou Tang. Deep learning face attributes in the wild. In IEEE International Conference on Computer Vision, pages 3730-3738, 2015. 2, 6", + "[35] Kede Ma, Zhengfang Duanmu, Qingbo Wu, Zhou Wang, Hongwei Yong, Hongliang Li, and Lei Zhang. Waterloo exploration database: New challenges for image quality assessment models. IEEE Transactions on Image Processing, pages 1004-1016, 2016. 8", + "[36] Sachit Menon, Alexandru Damian, Shijia Hu, Nikhil Ravi, and Cynthia Rudin. PULSE: Self-supervised photo upsampling via latent space exploration of generative models. In IEEE Conference on Computer Vision and Pattern Recognition, pages 2437-2445, 2020. 1", + "[37] Nikhil Mishra, Mostafa Rohaninejad, Xi Chen, and Pieter Abbeel. A simple neural attentive meta-learner. arXiv preprint arXiv:1707.03141, 2017. 3", + "[38] Anish Mittal, Rajiv Soundararajan, and Alan C Bovik. Making a \"completely blind\" image quality analyzer. IEEE Signal Processing Letters, pages 209-212, 2012. 6", + "[39] Chong Mou, Yanze Wu, Xintao Wang, Chao Dong, Jian Zhang, and Ying Shan. Metric learning based interactive modulation for real-world super-resolution. In European Conference on Computer Vision, pages 723-740, 2022. 6, 7, 8", + "[40] Boris Oreshkin, Pau Rodríguez López, and Alexandre Lacoste. TADAM: Task dependent adaptive metric for improved few-shot learning. Advances in Neural Information Processing Systems, pages 719-729, 2018. 3", + "[41] Seobin Park, Jinsu Yoo, Donghyeon Cho, Jiwon Kim, and Tae Hyun Kim. Fast adaptation to super-resolution networks via meta-learning. In European Conference on Computer Vision, pages 754-769, 2020. 3, 4" + ], + "bbox": [ + 104, + 148, + 472, + 844 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[42] Assaf Shocher, Nadav Cohen, and Michal Irani. \"zero-shot\" super-resolution using deep internal learning. In IEEE Conference on Computer Vision and Pattern Recognition, pages 3118-3126, 2018. 1, 2", + "[43] Jae Woong Soh, Sunwoo Cho, and Nam Ik Cho. Meta-transfer learning for zero-shot super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 3516-3525, 2020. 3, 4", + "[44] Qianru Sun, Yaoyao Liu, Tat-Seng Chua, and Bernt Schiele. Meta-transfer learning for few-shot learning. In IEEE Conference on Computer Vision and Pattern Recognition, pages 403-412, 2019. 3", + "[45] Flood Sung, Yongxin Yang, Li Zhang, Tao Xiang, Philip HS Torr, and Timothy M Hospedales. Learning to compare: Relation network for few-shot learning. In IEEE Conference on Computer Vision and Pattern Recognition, pages 1199-1208, 2018. 3", + "[46] Radu Timofte, Eirikur Agustsson, Luc Van Gool, Ming-Hsuan Yang, and Lei Zhang. NTIRE 2017 challenge on single image super-resolution: Methods and results. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 114-125, 2017. 6, 8", + "[47] Dmitry Ulyanov, Andrea Vedaldi, and Victor Lempitsky. Deep image prior. In IEEE Conference on Computer Vision and Pattern Recognition, pages 9446-9454, 2018. 1, 2", + "[48] Oriol Vinyals, Charles Blundell, Timothy Lillicrap, Daan Wierstra, et al. Matching networks for one shot learning. Advances in Neural Information Processing Systems, pages 3630-3638, 2016. 3", + "[49] Longguang Wang, Yingqian Wang, Xiaoyu Dong, Qingyu Xu, Jungang Yang, Wei An, and Yulan Guo. Unsupervised degradation representation learning for blind superresolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 10581-10590, 2021. 2", + "[50] Xintao Wang, Yu Li, Honglun Zhang, and Ying Shan. Towards real-world blind face restoration with generative facial prior. In IEEE Conference on Computer Vision and Pattern Recognition, pages 9168-9178, 2021. 1, 3, 4", + "[51] Xintao Wang, Liangbin Xie, Chao Dong, and Ying Shan. Real-ESRGAN: Training real-world blind super-resolution with pure synthetic data. In IEEE International Conference on Computer Vision, pages 1905–1914, 2021. 1, 2, 5, 6, 7, 8", + "[52] Xintao Wang, Ke Yu, Chao Dong, and Chen Change Loy. Recovering realistic texture in image super-resolution by deep spatial feature transform. In IEEE Conference on Computer Vision and Pattern Recognition, pages 606-615, 2018. 8", + "[53] Xintao Wang, Ke Yu, Shixiang Wu, Jinjin Gu, Yihao Liu, Chao Dong, Yu Qiao, and Chen Change Loy. ESRGAN: Enhanced super-resolution generative adversarial networks. In European Conference on Computer Vision Workshops, pages 63-79, 2018. 2, 4, 6, 8", + "[54] Zhouxia Wang, Jiawei Zhang, Runjian Chen, Wenping Wang, and Ping Luo. RestoreFormer: High-quality blind face restoration from undegraded key-value pairs. In IEEE Conference on Computer Vision and Pattern Recognition, pages 17491-17500, 2022. 3" + ], + "bbox": [ + 502, + 149, + 868, + 844 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "13043", + "bbox": [ + 465, + 875, + 504, + 885 + ], + "page_idx": 10 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[55] Pengxu Wei, Ziwei Xie, Hannan Lu, Zongyuan Zhan, Qixiang Ye, Wangmeng Zuo, and Liang Lin. Component divide-and-conquer for real-world image super-resolution. In European Conference on Computer Vision, pages 101-117, 2020. 1, 2", + "[56] Shuo Yang, Ping Luo, Chen Change Loy, and Xiaou Tang. Wider face: A face detection benchmark. In IEEE Conference on Computer Vision and Pattern Recognition, pages 5525-5533, 2016. 6", + "[57] Tao Yang, Peiran Ren, Xuansong Xie, and Lei Zhang. Gan prior embedded network for blind face restoration in the wild. In IEEE Conference on Computer Vision and Pattern Recognition, pages 672-681, 2021. 1, 3, 4, 5, 7, 9", + "[58] Yuan Yuan, Siyuan Liu, Jiawei Zhang, Yongbing Zhang, Chao Dong, and Liang Lin. Unsupervised image superresolution using cycle-in-cycle generative adversarial networks. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 701-710, 2018. 2", + "[59] Kai Zhang, Jingyun Liang, Luc Van Gool, and Radu Timofte. Designing a practical degradation model for deep blind image super-resolution. In IEEE International Conference on Computer Vision, pages 4791-4800, 2021. 1, 2, 6, 7, 8", + "[60] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In IEEE Conference on Computer Vision and Pattern Recognition, pages 586-595, 2018. 5, 6", + "[61] Xuaner Zhang, Qifeng Chen, Ren Ng, and Vladlen Koltun. Zoom to learn, learn to zoom. In IEEE Conference on Computer Vision and Pattern Recognition, pages 3762-3770, 2019. 1", + "[62] Heliang Zheng, Huan Yang, Jianlong Fu, Zheng-Jun Zha, and Jiebo Luo. Learning conditional knowledge distillation for degraded-reference image quality assessment. In IEEE International Conference on Computer Vision, pages 10242-10251, 2021. 2, 4", + "[63] Shangchen Zhou, Kelvin CK Chan, Chongyi Li, and Chen Change Loy. Towards robust blind face restoration with codebook lookup transformer. arXiv preprint arXiv:2206.11253, 2022. 1, 3, 9", + "[64] Feida Zhu, Junwei Zhu, Wenqing Chu, Xinyi Zhang, Xiaozhong Ji, Chengjie Wang, and Ying Tai. Blind face restoration via integrating face shape and generative priors. In IEEE Conference on Computer Vision and Pattern Recognition, pages 7662-7671, 2022. 3, 4" + ], + "bbox": [ + 104, + 148, + 470, + 694 + ], + "page_idx": 11 + }, + { + "type": "page_number", + "text": "13044", + "bbox": [ + 465, + 875, + 504, + 885 + ], + "page_idx": 11 + } +] \ No newline at end of file diff --git a/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/ed6327a3-66bd-4260-9c23-011c9182cd69_model.json b/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/ed6327a3-66bd-4260-9c23-011c9182cd69_model.json new file mode 100644 index 0000000000000000000000000000000000000000..4f433ab3b00cc19829bb0944f0b5804198385896 --- /dev/null +++ b/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/ed6327a3-66bd-4260-9c23-011c9182cd69_model.json @@ -0,0 +1,3007 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.096, + 0.009, + 0.171, + 0.047 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.233, + 0.008, + 0.816, + 0.049 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.255, + 0.182, + 0.717, + 0.221 + ], + "angle": 0, + "content": "MetaF2N: Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces" + }, + { + "type": "text", + "bbox": [ + 0.261, + 0.252, + 0.705, + 0.269 + ], + "angle": 0, + "content": "Zhicun Yin\\(^{1}\\) Ming Liu\\(^{1(\\boxtimes)}\\) Xiaoming Li\\(^{1}\\) Hui Yang\\(^{2}\\)" + }, + { + "type": "text", + "bbox": [ + 0.354, + 0.269, + 0.618, + 0.284 + ], + "angle": 0, + "content": "Longan Xiao2 Wangmeng Zuo1,3" + }, + { + "type": "text", + "bbox": [ + 0.142, + 0.284, + 0.832, + 0.299 + ], + "angle": 0, + "content": "\\(^{1}\\) Harbin Institute of Technology \\(^{2}\\) Shanghai Transsion Co, Ltd \\(^{3}\\) Peng Cheng Laboratory" + }, + { + "type": "text", + "bbox": [ + 0.176, + 0.302, + 0.797, + 0.313 + ], + "angle": 0, + "content": "cszcyin@outlook.com, csmliu@outlook.com, csxml@gmail.com, wmzuo@hit.edu.cn" + }, + { + "type": "title", + "bbox": [ + 0.251, + 0.344, + 0.323, + 0.357 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.371, + 0.474, + 0.735 + ], + "angle": 0, + "content": "Due to their highly structured characteristics, faces are easier to recover than natural scenes for blind image super-resolution. Therefore, we can extract the degradation representation of an image from the low-quality and recovered face pairs. Using the degradation representation, realistic low-quality images can then be synthesized to fine-tune the super-resolution model for the real-world low-quality image. However, such a procedure is time-consuming and laborious, and the gaps between recovered faces and the ground-truths further increase the optimization uncertainty. To facilitate efficient model adaptation towards image-specific degradations, we propose a method dubbed MetaF2N, which leverages the contained Faces to fine-tune model parameters for adapting to the whole Natural image in a Meta-learning framework. The degradation extraction and low-quality image synthesis steps are thus circumvented in our MetaF2N, and it requires only one fine-tuning step to get decent performance. Considering the gaps between the recovered faces and groundtruths, we further deploy a MaskNet for adaptively predicting loss weights at different positions to reduce the impact of low-confidence areas. To evaluate our proposed MetaF2N, we have collected a real-world low-quality dataset with one or multiple faces in each image, and our MetaF2N achieves superior performance on both synthetic and real-world datasets. Source code, pre-trained models, and collected datasets are available at https://github.com/yinzhicun/MetaF2N." + }, + { + "type": "title", + "bbox": [ + 0.104, + 0.757, + 0.226, + 0.771 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.779, + 0.471, + 0.845 + ], + "angle": 0, + "content": "With the development of dataset construction, network design, and many other relevant methods, blind image super-resolution (SR) [9, 33] has acquired enormous progress in recent years. To construct pairwise low-/high-quality samples for training the image SR models, typically" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.345, + 0.869, + 0.463 + ], + "angle": 0, + "content": "one can capture low- and high-quality pairs by adjusting the focal length of cameras [5, 55, 61] and shooting distance [8], or synthesize low-quality images via degradation modeling [26, 51, 59]. However, these methods can only cover a limited and biased range of degradations, which is insufficient for real-world applications. Besides, most existing blind image SR methods [51, 59] train a static model for all testing scenarios, greatly limiting their flexibility and generalization ability." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.465, + 0.869, + 0.713 + ], + "angle": 0, + "content": "In order to break the restriction of limited training sets, self-supervised learning has been introduced to train a model for each low-quality image, without requiring pairwise ground-truths [10, 42, 47]. Although these methods exhibit a great deal of flexibility, they largely rely on certain priors or assumptions, showing inferior image SR performance. Recently, Li et al. [26] reached a better compromise on the requirement of ground-truths and proposed ReDegNet by leveraging the faces contained in natural images. In specific, the face regions in a real-world low-quality natural image are processed via blind face SR methods [36, 50, 57, 63], which have achieved appealing results thanks to the highly structured characteristics of faces. Then, the low-quality and recovered face pairs can be utilized to model the degradations in the image. Finally, more low-quality images are synthesized with the degradation representations for fine-tuning the SR model. With the above design, ReDegNet [26] is flexible to process a single image or a batch of images with diverse degradations." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.714, + 0.87, + 0.846 + ], + "angle": 0, + "content": "Although ReDegNet [26] achieves superior SR performance, especially in specific scenarios (i.e., fine-tuning with faces within the test image), there are still several limitations. On the one hand, the training procedure is time-consuming and computationally intensive, where the modules for degradation representation extraction and low-quality image synthesis are jointly optimized. Furthermore, when the model is intended to deal with a single low-quality image, it is difficult to determine when to terminate the training process for avoiding under-fitting or over-fitting." + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.876, + 0.505, + 0.887 + ], + "angle": 0, + "content": "13033" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.102, + 0.149, + 0.471, + 0.252 + ], + "angle": 0, + "content": "On the other hand, even though the faces processed by the blind face restoration methods show appealing quality, there inevitably exist gaps between the recovered faces and the real ground-truths. Such gaps may affect the degradation representation accuracy and further hamper the training of the SR model. These problems have a large impact on the SR performance, especially when the model is fine-tuned for image-specific super-resolution." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.253, + 0.474, + 0.435 + ], + "angle": 0, + "content": "To remedy the aforementioned problems regarding training efforts and data gaps, we propose an efficient and effective method dubbed MetaF2N. In specific, the SR model directly fine-tunes the parameters from the low-quality and recovered face pairs, then uses the fine-tuned parameters to process the whole natural image. As such, the cumbersome degradation extraction and low-quality image synthesis steps are circumvented in our method, which avoids the interference of degradation modeling errors. In order to stabilize and accelerate the fine-tuning process during inference, we adopt the model-agnostic meta-learning [11] framework in the training phase, resulting in a much more practical model adaptation procedure that can be finished in a single fine-tuning step." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.435, + 0.474, + 0.653 + ], + "angle": 0, + "content": "Additionally, considering the gaps between low-quality faces and that processed by blind face restoration methods, we argue that treating all pixels equally will magnify the effect of the errors. Therefore, we further deploy a MaskNet, which adaptively predicts loss weights for different positions, to fulfill that the recovered face regions more similar to the ground-truths are assigned with higher loss weights. Ideally, the weight map should be extracted from the recovered faces and the ground-truths. Unfortunately, the ground-truths are unavailable during inference. Considering that predicting the loss weight map is similar to the image quality assessment (IQA) task, following the idea of degraded-reference IQA methods [2, 62], the MaskNet instead takes the low-quality and recovered faces as input. According to our observation, typically the areas closer to the ground-truth are assigned with larger weights and vice versa, which is consistent with the intuitions." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.655, + 0.472, + 0.77 + ], + "angle": 0, + "content": "For evaluating the proposed MetaF2N, we have constructed several synthetic datasets based on FFHQ [21] and CelebA [34]. To further show the effectiveness under real-world scenarios, we have also collected a real-world low-quality image dataset from the Internet and existing datasets, namely RealFaces200 (RF200), which contains a single face or multiple faces in each image. Extensive experiments show that our MetaF2N achieves superior performance on both synthetic and real-world datasets." + }, + { + "type": "text", + "bbox": [ + 0.12, + 0.772, + 0.443, + 0.785 + ], + "angle": 0, + "content": "In summary, the contribution of this paper includes," + }, + { + "type": "text", + "bbox": [ + 0.12, + 0.793, + 0.474, + 0.845 + ], + "angle": 0, + "content": "- We propose an efficient and effective method dubbed MetaF2N for blind image super-resolution, which takes advances of blind face restoration models and learns model adaptation from the face regions with" + }, + { + "type": "text", + "bbox": [ + 0.53, + 0.15, + 0.693, + 0.163 + ], + "angle": 0, + "content": "only one fine-tuning step." + }, + { + "type": "text", + "bbox": [ + 0.517, + 0.171, + 0.868, + 0.236 + ], + "angle": 0, + "content": "- Considering that the gaps between faces recovered by blind face restoration methods and the ground-truth ones may result in an inaccurate degradation modeling, a MaskNet is introduced for confidence prediction to mitigate the effect of the gaps." + }, + { + "type": "text", + "bbox": [ + 0.517, + 0.245, + 0.869, + 0.284 + ], + "angle": 0, + "content": "- A real-world low-quality image dataset with one or multiple faces in each image is collected, which will be helpful for face-guided blind image super-resolution." + }, + { + "type": "list", + "bbox": [ + 0.517, + 0.171, + 0.869, + 0.284 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.295, + 0.634, + 0.31 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.318, + 0.869, + 0.409 + ], + "angle": 0, + "content": "Recent efforts on blind image SR are mainly devoted to network design and data construction. We recommend [9, 33] for a comprehensive review of blind image SR, and focus on the most relevant methods of data construction, which are orthogonal to network design. We also briefly review recent advances in blind face restoration and meta-learning, which settle the foundation of this work." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.417, + 0.753, + 0.431 + ], + "angle": 0, + "content": "2.1. Blind Image Super-Resolution" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.437, + 0.87, + 0.71 + ], + "angle": 0, + "content": "Pairwise Data. Recent methods have made great efforts towards pairwise datasets that cover a wider range of real-world degradations and are better aligned. The most intuitive way is to collect pairwise samples. For example, Chen et al. [8] collected a City100 dataset by a DSLR and a smartphone via focal length and shooting distance adjustment, respectively. Since City100 was captured via postcards ignoring the geometries, Cai et al. [5] and Wei et al. [55] proposed to capture image pairs in real-world scenes and collected two datasets RealSR and DRealSR. Joze et al. [20] instead captured a dataset ImagePairs by embedding two cameras with different resolutions into a beam splitter. Another approach is to synthesize low-quality images from high-quality ones. Early methods [15, 18, 19, 53] utilized classical degradation models composed of blur, down-sampling, noise, etc., which are insufficient to model the real-world degradations. Zhang et al. [59] and Wang et al. [51] proposed to mimic real-world degradations via random combinations of different degradations. Albeit their progress on general image SR, these methods still cover a limited and biased range of real-world degradations." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.715, + 0.87, + 0.845 + ], + "angle": 0, + "content": "Unpaired Data. For better utilizing unpaired low-quality images that are easier to collect, some methods [12, 49, 58] proposed to extract the degradation representations or directly learn low-quality image synthesis in an unsupervised manner. Some methods [42, 47] utilized the texture recurrence across different scales or the priors embraced in the model learning process, and achieved image-specific blind image super-resolution in a self-supervised scheme. Purely relying on the unpaired samples or solely the low-quality ones, these methods may cover more degradations yet have" + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.876, + 0.506, + 0.887 + ], + "angle": 0, + "content": "13034" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.102, + 0.149, + 0.473, + 0.254 + ], + "angle": 0, + "content": "unsatisfactory performance in most cases. As a compromise, Li et al. [26] utilized the highly structured faces in real-world low-quality images, and extracted degradation representations from the low-quality faces and their counterparts recovered by blind face restoration methods. In this work, we take a step forward to solve the problems of Li et al. [26] and propose a MetaF2N framework for effective blind image SR of LR natural images containing faces." + }, + { + "type": "title", + "bbox": [ + 0.103, + 0.263, + 0.303, + 0.276 + ], + "angle": 0, + "content": "2.2. Blind Face Restoration" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.284, + 0.474, + 0.518 + ], + "angle": 0, + "content": "The diverse structures and complicated degradation jointly exacerbate the difficulties of blind natural image SR. In contrast, recent methods tend to leverage the structure information of specific images (e.g., faces [27-30, 57, 63] and text [31]), which have exhibited superior performance. Li et al. [28, 29] suggested using high-quality image(s) of the same person to provide personalized guidance. More general face restoration methods focused on constructing dictionaries [16, 27, 30, 54], semantic maps [7], or codebooks [63]. Recently, the generative structure prior based methods [6, 50, 57, 64] leveraged the representative pretrained StyleGAN models [22] and showed tremendous improvement in restoring fine-grained textures. Compared with natural images, these methods showed great generalization abilities, even in the presence of unknown degradations. This property has motivated us to employ face images on the inner loop of meta-learning to benefit the optimization toward better natural image SR." + }, + { + "type": "title", + "bbox": [ + 0.103, + 0.528, + 0.462, + 0.542 + ], + "angle": 0, + "content": "2.3. Image Super-Resolution with Meta-Learning" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.549, + 0.473, + 0.77 + ], + "angle": 0, + "content": "Meta-learning aims to learn adaptation to new domains or tasks by leveraging existing ones, which has demonstrated excellent generalization ability in many tasks [11, 14, 37, 40, 44, 45, 48]. Early works like MZSR [43] and MLSR [41] utilized meta-learning techniques to obtain a better initialization of model parameters that can be efficiently adapted to new low-quality images. Meta-KernelGAN [25] utilized meta-learning for efficient kernel estimation, which can be combined with non-blind SR methods. As one can see, MZSR [43] and MLSR [41] heavily rely on known degradations to construct inner loop supervisions, while Meta-KernelGAN is also restricted due to that the degradation representations formulated by kernels cannot well describe many real-world degradations. In this work, we adopt face regions as inner loop supervision and get rid of explicit degradation representations, which is more practical for real-world scenarios." + }, + { + "type": "title", + "bbox": [ + 0.103, + 0.783, + 0.221, + 0.798 + ], + "angle": 0, + "content": "3. Preliminary" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.805, + 0.472, + 0.845 + ], + "angle": 0, + "content": "For efficiently utilizing the generalization ability of face restoration methods in blind image SR and achieving flexibility on image-specific degradations, we have designed our" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.149, + 0.869, + 0.201 + ], + "angle": 0, + "content": "MetaF2N using the model-agnostic meta-learning framework (MAML) [11]. In this section, we briefly introduce the meta-learning framework based on MAML, which will be helpful for understanding our method." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.201, + 0.869, + 0.253 + ], + "angle": 0, + "content": "Typically, a deep model \\( f \\) is trained by a learning objective \\( \\mathcal{L} \\), which is directly dependent on the purpose of the task (e.g., \\( \\ell_1 \\) loss for fidelity in image SR tasks), and the optimal parameter \\( \\theta^* \\) is obtained via" + }, + { + "type": "equation", + "bbox": [ + 0.595, + 0.26, + 0.868, + 0.278 + ], + "angle": 0, + "content": "\\[\n\\theta^ {*} = \\arg \\min _ {\\theta} \\mathcal {L} (f (\\mathbf {x}; \\theta), \\mathbf {y}), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.284, + 0.868, + 0.31 + ], + "angle": 0, + "content": "where \\( \\mathbf{x} \\) and \\( \\mathbf{y} \\) are input and ground-truth. Intuitively, the objective of Eqn. (1) is to get a \\( \\theta \\) leading to the lowest \\( \\mathcal{L} \\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.31, + 0.868, + 0.362 + ], + "angle": 0, + "content": "Instead, MAML [11] aims to learn a parameter \\(\\theta^{*}\\), which can be efficiently fine-tuned toward the test sample with one or several steps. Taking the one-step situation as an example, the learning objective can be written as" + }, + { + "type": "equation", + "bbox": [ + 0.52, + 0.368, + 0.868, + 0.401 + ], + "angle": 0, + "content": "\\[\n\\theta^ {*} = \\arg \\min _ {\\theta} \\sum_ {T _ {i} \\sim p (T)} \\mathcal {L} ^ {T _ {i}} \\left(f (\\mathbf {x}; \\theta - \\alpha \\frac {\\partial \\mathcal {L} _ {i n} ^ {T _ {i}}}{\\partial \\theta}), \\mathbf {y}\\right), \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.407, + 0.869, + 0.536 + ], + "angle": 0, + "content": "where \\(p(T),\\mathcal{L}_{in}^{T_i}\\) , and \\(\\alpha\\) respectively represent the distribution (or collection) of tasks, the inner loop loss function for the task \\(T_{i}\\) , and learning rate for the inner loop. Here, we can regard \\(\\theta -\\alpha \\frac{\\partial\\mathcal{L}_{in}^{T_i}}{\\partial\\theta}\\) as a whole. Then, similar to Eqn. (1), the objective of Eqn. (2) can be interpreted as to get a \\(\\theta\\) leading to the lowest \\(\\mathcal{L}^{T_i}\\) after one back-propagation step w.r.t. \\(\\mathcal{L}_{in}^{T_i}\\) . In other words, a model trained under the MAML settings can adapt to new domains or tasks with a limited number of fine-tuning steps (i.e., \\(\\theta -\\alpha \\frac{\\partial\\mathcal{L}_{in}^{T_i}}{\\partial\\theta})\\)" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.544, + 0.586, + 0.557 + ], + "angle": 0, + "content": "4. Method" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.565, + 0.868, + 0.631 + ], + "angle": 0, + "content": "In this work, we aim to obtain a blind image SR model \\( f \\) which can be efficiently adapted to process the degradation of a real-world low-quality image \\( \\mathbf{I}_{LR} \\) under the guidance of its face regions (denoted by \\( \\mathbf{I}_{LR}^{\\ominus} \\)) and the faces processed by blind face restoration methods (denoted by \\( \\mathbf{I}_{BFR}^{\\ominus} \\))." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.631, + 0.869, + 0.683 + ], + "angle": 0, + "content": "Considering the complex and wide-range degradations in real-world low-quality images, we take advantage of MAML to design our method for processing image-specific degradations. Then Eqn. (2) can be rewritten as," + }, + { + "type": "equation", + "bbox": [ + 0.515, + 0.689, + 0.868, + 0.721 + ], + "angle": 0, + "content": "\\[\n\\theta^ {*} = \\arg \\min _ {\\theta} \\sum_ {T _ {i} \\sim p (T)} \\mathcal {L} ^ {T _ {i}} \\left(f \\left(\\mathbf {I} _ {L R}; \\theta - \\alpha \\frac {\\partial \\mathcal {L} _ {i n} ^ {T _ {i}}}{\\partial \\theta}\\right), \\mathbf {I}\\right), \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.727, + 0.869, + 0.78 + ], + "angle": 0, + "content": "where \\(p(T)\\) is the distribution of different degradations, \\(T_{i}\\) is the task for one specific degradation, \\(\\theta\\) is the parameter of \\(f\\) and \\(\\mathbf{I}\\) denotes the ground-truth image. The design of \\(\\mathcal{L}_{in}^{T_i}\\) will be given in Sec. 4.1." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.786, + 0.671, + 0.8 + ], + "angle": 0, + "content": "4.1. Inner Loop Design" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.805, + 0.869, + 0.845 + ], + "angle": 0, + "content": "One of the key factors of applying MAML [11] to blind image SR tasks is the design of \\(\\mathcal{L}_{in}^{T_i}\\) in Eqn. (3). Specifically, for adapting to the new degradation of an \\(\\mathbf{I}_{LR}\\), the" + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.876, + 0.505, + 0.887 + ], + "angle": 0, + "content": "13035" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.127, + 0.147, + 0.846, + 0.29 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.101, + 0.295, + 0.871, + 0.361 + ], + "angle": 0, + "content": "Figure 1: Pipeline of the proposed MetaF2N framework. During inference, the inner loop updates the initial parameter \\(\\theta\\) via a back-propagation step (dotted blue line), and the obtained \\(\\theta_{n}\\) is used to process the whole natural image in the outer loop. For training, the parameter update indeed relies on the gradients of outer loop loss \\(\\mathcal{L}^{T_i}\\) w.r.t. the initial parameter \\(\\theta\\) and the MaskNet parameter \\(\\theta_{\\mathbf{m}}\\) (dotted red line). For easier understanding, the steps of the pipeline (remarked by circled numbers) are introduced in Sec. 4.3. Please refer to Algorithms 1 and 2 for more details about the training and inference process." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.378, + 0.474, + 0.496 + ], + "angle": 0, + "content": "data for calculating \\(\\mathcal{L}_{in}^{T_i}\\) should have the same distribution as \\(\\mathbf{I}_{LR}\\). For MAML-based non-blind image SR methods [41, 43], one can construct inner loop data by further down-sampling \\(\\mathbf{I}_{LR}\\) with the known degradation \\(d\\) to get \\(\\mathbf{I}_{LLR} = d(\\mathbf{I}_{LR})\\). Then assuming the inner loop loss function to be \\(\\ell_1\\), we can obtain \\(\\mathcal{L}_{in}^{T_i} = \\| f(\\mathbf{I}_{LLR};\\theta) - \\mathbf{I}_{LR}\\|_1\\). However, for blind image SR, it is almost impossible to get extra image pairs with the same degradation as \\(\\mathbf{I}_{LR}\\) since \\(d\\) is unknown." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.497, + 0.474, + 0.653 + ], + "angle": 0, + "content": "Inspired by ReDegNet [26], which shows that faces can be utilized to extract the degradation representation for the whole image, we directly construct the inner loop data with the face regions. Thanks to the great generalization ability of blind face restoration methods [6,50,57,64], we are able to obtain a pseudo ground-truth for the face regions, which is denoted by \\(\\mathbf{I}_{BFR}^{\\ominus} = f_{BFR}(\\mathbf{I}_{LR}^{\\ominus};\\theta_{BFR})\\) , where \\(f_{BFR}\\) is the blind face restoration model with pre-trained parameter \\(\\theta_{BFR}\\) . In this paper, we follow ReDegNet [26] and adopt GPEN [57] as \\(f_{BFR}\\) . With the low-quality face regions \\(\\mathbf{I}_{LR}^{\\ominus}\\) and the recovered \\(\\mathbf{I}_{BFR}^{\\ominus}\\) , the inner loop loss function can be defined by" + }, + { + "type": "equation", + "bbox": [ + 0.192, + 0.664, + 0.471, + 0.681 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {i n} ^ {T _ {i}} = \\left\\| f \\left(\\mathbf {I} _ {L R} ^ {\\ominus}; \\theta\\right) - \\mathbf {I} _ {B F R} ^ {\\ominus} \\right\\| _ {1}. \\tag {4}\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.102, + 0.692, + 0.424, + 0.707 + ], + "angle": 0, + "content": "4.2. Adaptive Loss Weighting with MaskNet" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.713, + 0.471, + 0.793 + ], + "angle": 0, + "content": "Despite the appealing visual quality of recent blind face restoration methods, there inevitably exist gaps between generated faces \\(\\mathbf{I}_{BFR}^{\\ominus}\\) and ground-truth ones \\(\\mathbf{I}^{\\ominus}\\). For inaccurate regions, the degradation either explicitly (ReDeg-Net [26]) or implicitly (Our MetaF2N) described by the \\((\\mathbf{I}_{LR}^{\\ominus},\\mathbf{I}_{BFR}^{\\ominus})\\) pair also deviate from that by \\((\\mathbf{I}_{LR}^{\\ominus},\\mathbf{I}^{\\ominus})\\)." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.793, + 0.473, + 0.846 + ], + "angle": 0, + "content": "However, different regions of \\(\\mathbf{I}_{BFR}^{\\odot}\\) are treated equally in Eqn. (4), which will have negative effect on the final results. As a remedy, we propose to predict loss weights adaptively for different regions via a MaskNet. With the weight map" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.38, + 0.862, + 0.393 + ], + "angle": 0, + "content": "m generated by the MaskNet, Eqn. (4) can be rewritten as" + }, + { + "type": "equation", + "bbox": [ + 0.571, + 0.398, + 0.868, + 0.415 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {i n} ^ {T _ {i}} = \\left\\| \\mathbf {m} \\cdot \\left(f \\left(\\mathbf {I} _ {L R} ^ {\\ominus}; \\theta\\right) - \\mathbf {I} _ {B F R} ^ {\\ominus}\\right) \\right\\| _ {1}. \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.421, + 0.869, + 0.514 + ], + "angle": 0, + "content": "Ideally, \\(\\mathbf{m}\\) should be generated from the \\((\\mathbf{I}_{BFR}^{\\odot},\\mathbf{I}^{\\odot})\\) pair. Unfortunately, \\(\\mathbf{I}\\) is unavailable for test samples, a possible solution is solely predicting from \\(\\mathbf{I}_{BFR}^{\\odot}\\), yet the improvement is marginal. Analogous to degraded-reference IQA [2, 62] which predicts IQA metrics from (input, output) pairs rather than (output, GT) pairs in full-reference IQA, we predict \\(\\mathbf{m}\\) from the \\((\\mathbf{I}_{LR}^{\\odot},\\mathbf{I}_{BFR}^{\\odot})\\) pair, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.601, + 0.519, + 0.868, + 0.535 + ], + "angle": 0, + "content": "\\[\n\\mathbf {m} = f _ {\\mathbf {m}} \\left(\\mathbf {I} _ {L R} ^ {\\prime}, \\mathbf {I} _ {B F R} ^ {\\prime}; \\theta_ {\\mathbf {m}}\\right), \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.541, + 0.869, + 0.608 + ], + "angle": 0, + "content": "where \\(f_{\\mathbf{m}}\\) is the MaskNet, which is a simple network composed of 8 convolution layers shown in Fig. 2. As further shown in the ablation studies, the degraded-reference solution in Eqn. (6) performs better than solely predicting from \\(\\mathbf{I}_{BFR}^{\\odot}\\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.613, + 0.826, + 0.627 + ], + "angle": 0, + "content": "4.3. Overall Pipeline and Learning Objective" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.632, + 0.87, + 0.821 + ], + "angle": 0, + "content": "With the inner loop designed in Eqn. (5), we can build the pipeline as shown in Fig. 1. In specific, given a low-quality image \\(\\mathbf{I}_{LR}\\) containing face regions denoted by \\(\\mathbf{I}_{LR}^{\\ominus}\\), we pass \\(\\mathbf{I}_{LR}^{\\ominus}\\) through the SR network \\(f\\) and obtain the inner loop result \\(\\mathbf{I}_{SR}^{\\ominus}\\). For a fair comparison against existing methods, we take the model of Real-ESRGAN [53] as the SR network, whose parameter is used to initialize the \\(\\theta\\) in the inner loop. To construct supervision for the inner loop, we use a pre-trained GPEN [57] model, whose parameter is kept fixed in our whole pipeline. Then we can obtain the weight map \\(\\mathbf{m}\\) following Eqn. (6), as well as the inner loop loss \\(\\mathcal{L}_{in}^{T_i}\\) following Eqn. (5), which can be used to generate a temporary parameter \\(\\theta_{\\mathrm{n}} = \\theta -\\alpha \\frac{\\partial\\mathcal{L}_{in}^{T_i}}{\\partial\\theta}\\) for processing the whole natural image in the outer loop, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.545, + 0.826, + 0.869, + 0.847 + ], + "angle": 0, + "content": "\\[\n\\mathbf {I} _ {S R} = f \\left(\\mathbf {I} _ {L R}; \\theta_ {\\mathbf {n}}\\right) = f \\left(\\mathbf {I} _ {L R}; \\theta - \\alpha \\frac {\\partial \\mathcal {L} _ {i n} ^ {T _ {i}}}{\\partial \\theta}\\right) ⑥. \\tag {7}\n\\]" + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.876, + 0.506, + 0.887 + ], + "angle": 0, + "content": "13036" + } + ], + [ + { + "type": "code_caption", + "bbox": [ + 0.113, + 0.152, + 0.387, + 0.165 + ], + "angle": 0, + "content": "Algorithm 1: Training Process of MetaF2N" + }, + { + "type": "algorithm", + "bbox": [ + 0.107, + 0.167, + 0.47, + 0.546 + ], + "angle": 0, + "content": "Input: Distribution of different degradation restoration tasks \\(p(T)\\) High-quality natural image dataset \\(\\mathcal{D}_{HR}\\) High-quality face dataset \\(\\mathcal{D}_{\\odot}\\) Learning rates \\(\\alpha ,\\beta ,\\gamma ,\\eta\\) Output: Model parameter \\(\\theta ,\\theta_{\\mathbf{m}}\\) 1 Initialize \\(f,D\\) with \\(\\theta ,\\theta_{D}\\) from Real-ESRGAN [51] 2 Initialize \\(f_{BFR}\\) with \\(\\theta_{BFR}\\) from GPEN [57] 3 Random initialize \\(f_{\\mathbf{m}}\\) with \\(\\theta_{\\mathbf{m}}\\) 4 for all training steps do 5 Sample batch of tasks \\(T_{i}\\sim p(T)\\) 6 for all \\(T_{i}\\) do 7 Sample images \\(\\mathbf{I},\\mathbf{I}^{\\odot}\\) from \\(\\mathcal{D}_{\\mathcal{H}\\mathcal{R}}\\) and \\(\\mathcal{D}_{\\odot}\\) 8 Create \\(\\mathbf{I},\\mathbf{I}_{LR},\\mathbf{I}_{LR}^{\\odot}\\) of \\(T_{i}\\) 9 \\(\\mathbf{I}_{BFR}^{\\odot} = f_{BFR}(\\mathbf{I}_{LR}^{\\odot};\\theta_{BFR})\\) m \\(= f_{\\mathrm{m}}(\\mathbf{I}_{LR}^{\\odot},\\mathbf{I}_{BFR}^{\\odot};\\theta_{\\mathrm{m}})\\) for 1 step of inner loop do 12 \\(\\begin{array}{r}\\mathcal{L}_{in}^{T_i} = ||\\mathbf{m}\\cdot (f(\\mathbf{I}_{LR}^{\\odot};\\theta) - \\mathbf{I}_{BFR}^{\\odot})||_1\\\\ \\theta_{\\mathrm{n}}\\gets \\theta -\\alpha \\nabla_{\\theta}\\mathcal{L}_{in}^{T_i}(\\theta) \\end{array}\\) end 15 \\(\\mathbf{I}_{SR} = f(\\mathbf{I}_{LR};\\theta_{\\mathbf{n}})\\) 16 \\(\\mathcal{L}^{T_i}\\) is defined as Eqn. (13) 17 \\(\\mathcal{L}_D^{T_i}\\) is defined as Eqn. (11) end 19 \\(\\theta \\gets \\theta -\\beta \\nabla_{\\theta}\\sum_{T_i\\sim p(T)}\\mathcal{L}^{T_i}\\) 20 \\(\\theta_{\\mathrm{m}}\\gets \\theta_{\\mathrm{m}} - \\gamma \\nabla_{\\theta_{\\mathrm{m}}}\\sum_{T_i\\sim p(T)}\\mathcal{L}^{T_i}\\) 21 \\(\\theta_D\\gets \\theta_D - \\eta \\nabla_{\\theta_D}\\sum_{T_i\\sim p(T)}\\mathcal{L}_D^{T_i}\\) 22 end" + }, + { + "type": "code_caption", + "bbox": [ + 0.114, + 0.568, + 0.393, + 0.58 + ], + "angle": 0, + "content": "Algorithm 2: Inference Process of MetaF2N" + }, + { + "type": "algorithm", + "bbox": [ + 0.106, + 0.582, + 0.47, + 0.808 + ], + "angle": 0, + "content": "Input: LR test image \\(\\mathbf{I}_{LR}\\) Trained model parameter \\(\\theta ,\\theta_{\\mathrm{m}}\\) Pre-trained GPEN [57] parameter \\(\\theta_{BFR}\\) Fine-tuning steps \\(n\\) and learning rate \\(\\alpha\\) Output: Super-resolved image \\(\\mathbf{I}_{SR}\\) 1 Initialize \\(f,f_{\\mathbf{m}}\\) with \\(\\theta ,\\theta_{\\mathbf{m}}\\) 2 Initialize \\(f_{BFR}\\) with \\(\\theta_{BFR}\\) from GPEN [57] 3 Extract face regions \\(\\mathbf{I}_{LR}^{\\ominus}\\) from \\(\\mathbf{I}_{LR}\\) 4 \\(\\mathbf{I}_{BFR}^{\\ominus} = f_{BFR}(\\mathbf{I}_{LR}^{\\ominus};\\theta_{BFR})\\) 5 \\(\\mathbf{m} = f_{\\mathbf{m}}(\\mathbf{I}_{LR}^{\\ominus},\\mathbf{I}_{BFR}^{\\ominus};\\theta_{\\mathbf{m}})\\) 6 for n steps of inner loop do 7 \\(\\begin{array}{rl}{\\mathcal{L}_{in}} & {= \\| \\mathbf{m}\\cdot (f(\\mathbf{I}_{LR}^{\\ominus};\\theta) - \\mathbf{I}_{BFR}^{\\ominus})\\| _1}\\\\ {\\theta} & {\\leftarrow \\theta -\\alpha \\nabla_{\\theta}\\mathcal{L}_{in}(\\theta)} \\end{array}\\) 8 end 9 end 10 \\(\\theta_{\\mathbf{n}}\\gets \\theta\\) 11 \\(\\mathbf{I}_{SR} = f(\\mathbf{I}_{LR};\\theta_{\\mathbf{n}})\\) 12 return \\(\\mathbf{I}_{SR}\\)" + }, + { + "type": "image", + "bbox": [ + 0.511, + 0.146, + 0.86, + 0.281 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.543, + 0.283, + 0.825, + 0.296 + ], + "angle": 0, + "content": "Figure 2: The network structure of MaskNet." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.314, + 0.868, + 0.353 + ], + "angle": 0, + "content": "The above process (as remarked by the circled numbers) describes the pipeline of MetaF2N during inference and the first six steps in the training phase." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.353, + 0.868, + 0.404 + ], + "angle": 0, + "content": "For training MetaF2N, we also need to calculate the outer loop loss \\(⑦\\), which is composed of fidelity loss \\((\\ell_1)\\), LPIPS loss [60], and GAN loss [13]. In specific, the fidelity loss is" + }, + { + "type": "equation", + "bbox": [ + 0.625, + 0.404, + 0.868, + 0.419 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {1} = \\left\\| \\mathbf {I} _ {S R} - \\mathbf {I} \\right\\| _ {1}, \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.423, + 0.704, + 0.437 + ], + "angle": 0, + "content": "and the LPIPS loss is defined by" + }, + { + "type": "equation", + "bbox": [ + 0.59, + 0.444, + 0.868, + 0.459 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {L P I P S}} = \\| \\phi (\\mathbf {I} _ {S R}) - \\phi (\\mathbf {I}) \\| _ {2}, \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.466, + 0.868, + 0.505 + ], + "angle": 0, + "content": "where \\(\\phi\\) is the pre-trained AlexNet [24] feature extractor for calculating LPIPS. The adversarial loss follows the setting of Real-ESRGAN [51], which is defined by," + }, + { + "type": "equation", + "bbox": [ + 0.599, + 0.512, + 0.868, + 0.528 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {a d v}} = - \\mathbb {E} [ \\log (D (\\mathbf {I} _ {S R})) ], \\tag {10}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.534, + 0.868, + 0.56 + ], + "angle": 0, + "content": "where the discriminator \\(D\\) is iteratively trained along with the SR network, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.536, + 0.568, + 0.868, + 0.584 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {D} = - \\mathbb {E} [ \\log (D (\\mathbf {I})) - \\log (1 - D (\\mathbf {I} _ {S R})) ]. \\tag {11}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.59, + 0.868, + 0.668 + ], + "angle": 0, + "content": "Note that some works [25,32] have explored training GANs under the meta-learning structure, and all of them update the discriminator loss in both the inner loop and outer loop. However, to accelerate the training process and save memory, we only update the discriminator loss in the outer loop, which also shows satisfactory results." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.668, + 0.868, + 0.707 + ], + "angle": 0, + "content": "To improve the numerical stability and avoid gradient exploding/vanishing, we constrain the MaskNet \\( f_{\\mathbf{m}} \\) via a regularization term, which is defined by" + }, + { + "type": "equation", + "bbox": [ + 0.623, + 0.715, + 0.868, + 0.73 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {r e g}} = \\| \\mathbf {m} - \\mathbf {1} \\| _ {2}. \\tag {12}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.736, + 0.868, + 0.763 + ], + "angle": 0, + "content": "In summary, the learning objective of our MetaF2N (i.e., the outer loop loss) is" + }, + { + "type": "equation", + "bbox": [ + 0.524, + 0.77, + 0.868, + 0.786 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} ^ {T _ {\\mathrm {i}}} = \\lambda_ {1} \\mathcal {L} _ {1} + \\lambda_ {2} \\mathcal {L} _ {\\text {L P I I P S}} + \\lambda_ {3} \\mathcal {L} _ {\\text {a d v}} + \\lambda_ {4} \\mathcal {L} _ {\\text {r e g}}, \\tag {13}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.792, + 0.868, + 0.845 + ], + "angle": 0, + "content": "where the hyperparameters \\(\\lambda_1, \\lambda_2, \\lambda_3\\), and \\(\\lambda_4\\) are empirically set to 1, 0.5, 0.1, and 0.002, respectively. Please refer to Algorithms 1 and 2 for more details on the training and inference process of the proposed MetaF2N." + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.876, + 0.505, + 0.887 + ], + "angle": 0, + "content": "13037" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.103, + 0.148, + 0.227, + 0.162 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.103, + 0.169, + 0.344, + 0.184 + ], + "angle": 0, + "content": "5.1. Dataset and Training Details" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.189, + 0.474, + 0.372 + ], + "angle": 0, + "content": "Training Data. For synthesizing data to train the proposed MetaF2N, high-quality facial and natural images are required for inner and outer loop, respectively. It is worth noting that, the requirement on the training data is that \\(\\mathbf{I}_{LR}^{\\odot}\\) and \\(\\mathbf{I}_{LR}\\) share the identical degradation, but they are not necessarily from the same image. Therefore, to better leverage existing high-quality facial and natural image datasets, we use the first 30,000 images of the aligned FFHQ [21] dataset for the inner loop, and adopt DF2K1 with 3,450 images in total for the outer loop following recent blind image SR methods [26, 51, 59]. For a fair comparison against other methods, we follow the degradation setting of RealESRGAN [51] for low-quality image synthesis. More details are given in the supplementary material." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.377, + 0.473, + 0.403 + ], + "angle": 0, + "content": "Testing Data. To comprehensively evaluate the proposed MetaF2N, we have constructed several testing datasets." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.404, + 0.474, + 0.572 + ], + "angle": 0, + "content": "Synthetic datasets are built upon the in-the-wild version of FFHQ [21] and CelebA [34], where 1,000 high-quality images are extracted from each dataset, and faces occupy around \\(10\\%\\) areas of the whole image on average. With the high-quality images, we first construct two test datasets whose degradations are independent and identically distributed as the training set, which are denoted by \\(\\mathrm{FFHQ}_{iid}\\) and \\(\\mathrm{CelebA}_{iid}\\), respectively. For evaluating the generalization ability on out-of-distribution degradations, we further construct \\(\\mathrm{FFHQ}_{ood}\\) and \\(\\mathrm{CelebA}_{ood}\\) by changing the parameters of the degradation model, e.g., Gaussian blur \\(\\rightarrow\\) motion blur, Gaussian/Poisson noise \\(\\rightarrow\\) Speckle noise. The detailed parameters are in the supplementary material." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.573, + 0.473, + 0.638 + ], + "angle": 0, + "content": "A real-world dataset RealFaces200 (RF200) is also established for evaluation under a real scenario, which contains 200 real-world low-quality images collected from the Internet or existing datasets (e.g., WIDER FACE [56]), and there are one or multiple faces in each image." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.643, + 0.474, + 0.825 + ], + "angle": 0, + "content": "Implementation Details. The proposed MetaF2N mainly focuses on leveraging meta-learning for efficient model adaptation for blind image SR, which is independent of network architecture and can be incorporated into arbitrary second-order differentiable models. Therefore, we follow Real-ESRGAN [51], BSRGAN [59], and ReDegNet [26] to adopt the architecture of ESRGAN [53]. For training, each image is cropped into patches, and the patch size is \\(128 \\times 128\\) for the inner loop (i.e., \\(\\mathbf{I}_{LR}^{\\ominus}\\), \\(\\mathbf{I}_{BFR}^{\\ominus}\\), and \\(\\mathbf{I}_{SR}^{\\ominus}\\)) and \\(256 \\times 256\\) for the outer loop (i.e., \\(\\mathbf{I}_{LR}\\), \\(\\mathbf{I}_{SR}\\), and \\(\\mathbf{I}\\)). The Adam [23] optimizer with \\(\\beta_{1} = 0.5\\) and \\(\\beta_{2} = 0.999\\) is adopted. For the SR model \\(f\\), the learning rate (lr) of the inner and outer loops are \\(1 \\times 10^{-2}\\) and \\(3 \\times 10^{-5}\\), respectively, while the lr for the discriminator and MaskNet are \\(1 \\times 10^{-4}\\)." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.149, + 0.869, + 0.174 + ], + "angle": 0, + "content": "The MetaF2N is trained for one week and all experiments are conducted on a server with one RTX A6000 GPU." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.183, + 0.843, + 0.197 + ], + "angle": 0, + "content": "5.2. Comparison with State-of-the-art Methods" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.203, + 0.87, + 0.451 + ], + "angle": 0, + "content": "To show the effectiveness of the proposed MetaF2N, we compare with several state-of-the-art blind image SR methods, including ESRGAN [53], RealSR [5], Real-ESRGAN [51], BSRGAN [59], MM-RealSR [39], and RedegNet [26]. For quantitative evaluation, we utilize PSNR, LPIPS [60], FID [17], and NIQE [38] for synthetic datasets. As for the real-world dataset, since no ground-truth is available, PSNR and LPIPS are omitted. It is worth noting that KID is more accurate and appropriate than FID when evaluating the quality of images with a smaller amount of samples [3]. Thus we use KID [3] and NIQE [38] for quantitative evaluation on our RF200 dataset. To accurately calculate the distance between SR results and real-world high-quality images (i.e., FID and KID), we construct these types of reference images following [4], which estimates a blurriness score based on the total variance of the Laplacian of an image. Finally, 3,808 high-quality images are selected from the in-the-wild version of FFHQ [21], whose scores are higher than the threshold defined in [4]." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.455, + 0.87, + 0.662 + ], + "angle": 0, + "content": "Quantitative Comparison. The quantitative evaluation results are provided in Tabs. 1 and 2. We provide three results of our Meta-F2N, i.e., Ours (1), Ours (10), and Ours (20), where the number in the parentheses denotes the amount of fine-tuning steps during inference. All three models are initialized with the same parameter \\(\\theta\\). For the degradations independent and identically distributed as the training set (i.e., \\(\\mathrm{FFHQ}_{iid}\\) and CelebA\\(_{iid}\\)), our MetaF2N can achieve superior performance on LPIPS, FID, and NIQE with only one fine-tuning step, and can surpass most of the competing methods on PSNR. Besides, with more fine-tuning iterations, the image quality can be further enhanced. For out-of-distribution degradations in Tab. 2 (i.e., \\(\\mathrm{FFHQ}_{ood}\\), CelebA\\(_{ood}\\), and RF200), the trends are similar to Tab. 1, and our MetaF2N again outperforms others on most metrics, especially on the real-world RF200 dataset." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.663, + 0.87, + 0.845 + ], + "angle": 0, + "content": "As for the competing methods, ESRGAN [53] and RealSR [5] are trained with simple degradation models, which lead to unsatisfactory performance under more complex and realistic degradations. Real-ESRGAN [51], BSRGAN [59], MM-RealSR [39], and ReDegNet [26] leverage more realistic degradation models or even real-world degradations, which contribute to much better results, yet their performance is still limited by the deterministic model and fixed degradation range. Furthermore, we also fine-tune ReDegNet [26] on RF200, and the results are provided in Tab. 2 (ReDegNet†). Compared to MetaF2N that achieves decent performance with only one fine-tuning step, marginal improvements are observed on NIQE even the ReDegNet [26] is carefully fine-tuned hundreds iterations for each image." + }, + { + "type": "page_footnote", + "bbox": [ + 0.12, + 0.832, + 0.461, + 0.845 + ], + "angle": 0, + "content": "\\(^{1}\\)DF2K is the combination of DIV2K [1] and Flickr2K [46] datasets." + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.876, + 0.506, + 0.887 + ], + "angle": 0, + "content": "13038" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.13, + 0.147, + 0.231, + 0.195 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.13, + 0.196, + 0.231, + 0.286 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.13, + 0.287, + 0.231, + 0.34 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.146, + 0.34, + 0.214, + 0.35 + ], + "angle": 0, + "content": "Synthetic LR" + }, + { + "type": "image", + "bbox": [ + 0.232, + 0.147, + 0.333, + 0.195 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.232, + 0.196, + 0.333, + 0.286 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.232, + 0.287, + 0.333, + 0.34 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.232, + 0.34, + 0.333, + 0.35 + ], + "angle": 0, + "content": "Real-ESRGAN [51]" + }, + { + "type": "image", + "bbox": [ + 0.334, + 0.147, + 0.435, + 0.195 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.334, + 0.196, + 0.435, + 0.286 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.334, + 0.287, + 0.435, + 0.34 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.348, + 0.34, + 0.422, + 0.35 + ], + "angle": 0, + "content": "BSRGAN [59]" + }, + { + "type": "image", + "bbox": [ + 0.436, + 0.147, + 0.536, + 0.195 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.436, + 0.196, + 0.537, + 0.286 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.436, + 0.287, + 0.537, + 0.34 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.441, + 0.34, + 0.531, + 0.35 + ], + "angle": 0, + "content": "MM-RealSR [39]" + }, + { + "type": "image", + "bbox": [ + 0.537, + 0.147, + 0.638, + 0.195 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.537, + 0.196, + 0.638, + 0.286 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.537, + 0.287, + 0.638, + 0.34 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.549, + 0.34, + 0.627, + 0.35 + ], + "angle": 0, + "content": "ReDegNet [26]" + }, + { + "type": "image", + "bbox": [ + 0.639, + 0.147, + 0.74, + 0.195 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.64, + 0.196, + 0.74, + 0.286 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.64, + 0.287, + 0.74, + 0.34 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.676, + 0.341, + 0.703, + 0.35 + ], + "angle": 0, + "content": "Ours" + }, + { + "type": "image", + "bbox": [ + 0.741, + 0.147, + 0.842, + 0.195 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.741, + 0.196, + 0.842, + 0.286 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.741, + 0.287, + 0.842, + 0.34 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.758, + 0.341, + 0.825, + 0.35 + ], + "angle": 0, + "content": "Ground-truth" + }, + { + "type": "image_caption", + "bbox": [ + 0.102, + 0.351, + 0.868, + 0.377 + ], + "angle": 0, + "content": "Figure 3: Visual comparison against state-of-the-art blind SR methods on synthetic datasets. Note that the results of Ours are produced by MetaF2N with one-step fine-tuning. Please zoom in for better observation." + }, + { + "type": "image", + "bbox": [ + 0.13, + 0.383, + 0.231, + 0.442 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.13, + 0.443, + 0.231, + 0.513 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.13, + 0.513, + 0.231, + 0.611 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.142, + 0.612, + 0.22, + 0.622 + ], + "angle": 0, + "content": "Real-world LR" + }, + { + "type": "image", + "bbox": [ + 0.232, + 0.383, + 0.333, + 0.442 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.232, + 0.443, + 0.333, + 0.513 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.232, + 0.513, + 0.333, + 0.611 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.232, + 0.612, + 0.333, + 0.622 + ], + "angle": 0, + "content": "Real-ESRGAN [51]" + }, + { + "type": "image", + "bbox": [ + 0.334, + 0.383, + 0.435, + 0.442 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.334, + 0.443, + 0.435, + 0.513 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.334, + 0.513, + 0.435, + 0.611 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.348, + 0.612, + 0.422, + 0.622 + ], + "angle": 0, + "content": "BSRGAN [59]" + }, + { + "type": "image", + "bbox": [ + 0.436, + 0.383, + 0.536, + 0.442 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.436, + 0.443, + 0.537, + 0.513 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.436, + 0.513, + 0.537, + 0.611 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.441, + 0.612, + 0.53, + 0.622 + ], + "angle": 0, + "content": "MM-RealSR [39]" + }, + { + "type": "image", + "bbox": [ + 0.537, + 0.383, + 0.638, + 0.442 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.537, + 0.443, + 0.638, + 0.513 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.537, + 0.513, + 0.638, + 0.611 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.549, + 0.612, + 0.627, + 0.622 + ], + "angle": 0, + "content": "ReDegNet [26]" + }, + { + "type": "image", + "bbox": [ + 0.639, + 0.383, + 0.74, + 0.442 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.64, + 0.443, + 0.74, + 0.513 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.64, + 0.513, + 0.74, + 0.611 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.648, + 0.612, + 0.731, + 0.622 + ], + "angle": 0, + "content": "ReDegNet [26]" + }, + { + "type": "image", + "bbox": [ + 0.741, + 0.383, + 0.842, + 0.442 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.741, + 0.443, + 0.842, + 0.513 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.741, + 0.513, + 0.842, + 0.611 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.779, + 0.612, + 0.805, + 0.622 + ], + "angle": 0, + "content": "Ours" + }, + { + "type": "image_caption", + "bbox": [ + 0.102, + 0.624, + 0.867, + 0.65 + ], + "angle": 0, + "content": "Figure 4: Visual comparison against state-of-the-art blind SR methods on real-world low-quality images in our RF200 dataset. ReDegNet† means that model is fine-tuned for each image following the official configurations of ReDegNet [26]." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.662, + 0.473, + 0.792 + ], + "angle": 0, + "content": "Qualitative Comparison. Apart from the quantitative comparison, we also compare our MetaF2N with state-of-the-art blind image SR methods qualitatively. Due to the space limit, we show the results generated by Ours (1), which is fine-tuned for 1 step with the face regions, and more qualitative results (including those generated by Ours (10) and Ours (20)) are provided in the supplementary material. As shown in Figs. 3 and 4, our results are much clearer and contain more photo-realistic textures, which can be ascribed to the effectiveness of our image-specific fine-tuning scheme." + }, + { + "type": "title", + "bbox": [ + 0.103, + 0.799, + 0.36, + 0.811 + ], + "angle": 0, + "content": "5.3. The Visual Results of MaskNet" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.818, + 0.472, + 0.845 + ], + "angle": 0, + "content": "To better explain the effect of our MaskNet, we calculate the error map \\( EM \\) between ground-truth faces \\( \\mathbf{I}^{\\odot} \\) and" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.662, + 0.868, + 0.688 + ], + "angle": 0, + "content": "GPEN [57] generated faces \\(\\mathbf{I}_{BFR}^{\\odot}\\) directly through subtraction and normalization, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.596, + 0.693, + 0.868, + 0.724 + ], + "angle": 0, + "content": "\\[\nE M = \\frac {\\left| \\mathbf {I} ^ {\\ominus} - \\mathbf {I} _ {B F R} ^ {\\ominus} \\right|}{\\operatorname* {m a x} \\left(\\left| \\mathbf {I} ^ {\\ominus} - \\mathbf {I} _ {B F R} ^ {\\ominus} \\right|\\right)}. \\tag {14}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.727, + 0.87, + 0.845 + ], + "angle": 0, + "content": "In Fig. 5, we show the predicted \\(\\mathbf{m}\\) and \\(1 - EM\\). One can see that the predicted \\(\\mathbf{m}\\) follows similar distribution to \\(1 - EM\\), indicating that our MaskNet has the ability to predict the gap between generated faces and real ones, which benefits the blind image SR performance. Besides, the predicted \\(\\mathbf{m}\\) is smoother than \\(1 - EM\\), due to that 1) \\(\\mathbf{m}\\) is predicted from \\((\\mathbf{I}_{LR}^{\\ominus}\\) and \\(\\mathbf{I}_{BFR}^{\\ominus})\\), which lead to less accurate results, and 2) a regularization term \\(\\mathcal{L}_{\\mathrm{reg}} = \\| \\mathbf{m} - 1\\|_2\\) is applied to constrain \\(\\mathbf{m}\\) not to deviate too far from 1." + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.876, + 0.506, + 0.887 + ], + "angle": 0, + "content": "13039" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.102, + 0.151, + 0.871, + 0.204 + ], + "angle": 0, + "content": "Table 1: Quantitative comparison on synthetic datasets with independent and identically distributed degradations as the training set. We also show the datasets used for training each method. Note that RealFaces used by ReDegNet [26] consists of 10,000 real-world low-quality face images collected by the authors. The numbers in the parentheses are the image-specific fine-tuning steps of our MetaF2N during inference. The best and second-best results are highlighted by bold and underline." + }, + { + "type": "table", + "bbox": [ + 0.139, + 0.206, + 0.83, + 0.349 + ], + "angle": 0, + "content": "
MethodsTraining SetFFHQiiidCelebAiid
PSNR↑LPIPS↓FID↓NIQE↓PSNR↑LPIPS↓FID↓NIQE↓
ESRGAN [53]DF2K [1,46], OST [52]25.100.642123.677.5624.780.55599.106.27
RealSR [19]DF2K [1,46]25.390.597122.237.5924.740.54999.465.77
Real-ESRGAN [51]DF2K [1,46], OST [52]26.350.29350.704.8525.810.31151.695.00
BSRGAN [59]DF2K [1,46], FFFHQ [21], WED [35]26.270.30550.984.6325.860.30950.054.83
MM-RealSR [39]DF2K [1,46], OST [52]25.390.29550.834.5824.940.31152.304.76
ReDegNet [26]DF2K [1,46], FFFHQ [21], RealFaces25.640.30957.044.7925.170.32956.844.94
Ours (1)DF2K [1,46], FFFHQ [21]26.130.28144.943.8125.630.28945.723.97
Ours (10)DF2K [1,46], FFFHQ [21]26.220.28044.943.8725.700.28945.434.03
Ours (20)DF2K [1,46], FFFHQ [21]26.300.27944.513.9425.760.28945.224.10
" + }, + { + "type": "table_caption", + "bbox": [ + 0.101, + 0.359, + 0.871, + 0.412 + ], + "angle": 0, + "content": "Table 2: Quantitative comparison on synthetic datasets with out-of-distribution degradations and the collected real-world dataset RF200. ReDegNet† means that model is fine-tuned for each image following the official configurations of ReDeg-Net [26]. The numbers in the parentheses are the image-specific fine-tuning steps of our MetaF2N during inference. The best and second-best results are highlighted by bold and underline." + }, + { + "type": "table", + "bbox": [ + 0.2, + 0.413, + 0.77, + 0.568 + ], + "angle": 0, + "content": "
MethodsFFHQoodCelebAoodRF200
PSNR↑LPIPS↓FID↓NIQE↓PSNR↑LPIPS↓FID↓NIQE↓KID↓NIQE↓
ESRGAN [53]24.690.659101.436.9424.070.56787.615.6421.85.32
RealSR [19]24.910.58797.426.3323.980.56790.305.5121.95.00
Real-ESRGAN [51]25.730.30247.875.3425.070.32248.775.4322.43.82
BSRGAN [59]25.730.29846.404.7825.330.31348.124.9122.14.11
MM-RealSR [39]25.030.29747.304.9924.410.31748.765.1022.14.12
ReDegNet [26]25.540.30448.475.0924.760.33152.335.2823.54.07
ReDegNet†[26]--------23.83.56
Ours (1)25.490.28445.074.2224.870.29747.034.3221.23.03
Ours (10)25.570.28444.644.3024.930.29746.504.3921.03.08
Ours (20)25.650.28344.304.3625.000.29746.234.4720.83.12
" + }, + { + "type": "title", + "bbox": [ + 0.103, + 0.585, + 0.257, + 0.599 + ], + "angle": 0, + "content": "5.4. Ablation Studies" + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.605, + 0.471, + 0.684 + ], + "angle": 0, + "content": "To verify the effectiveness of the components of the proposed MetaF2N, we have also conducted several ablation studies. Without loss of generality, all ablation studies are performed with \\(\\mathrm{FFHQ}_{i id}\\) based on Ours (1). Due to the space limit, qualitative results of ablation studies are given in the supplementary material." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.688, + 0.474, + 0.845 + ], + "angle": 0, + "content": "MaskNet Configuration. To show the effectiveness of the MaskNet, we train a variant of our MetaF2N by removing the MaskNet. Besides, as introduced in Sec. 1, we design the MaskNet inspired by degraded-reference IQA methods, which takes both low-quality and restored faces as input (denoted by \\(\\mathrm{MaskNet}_{DR}\\)). For verifying the design, we also consider another variant of MetaF2N which utilizes the non-reference scheme, i.e., only the restored face is taken by the MaskNet (denoted by \\(\\mathrm{MaskNet}_{NR}\\)). As shown in Tab. 3, the deployment of MaskNet brings considerable improvements, and utilizing the low-quality face image as a reference is also useful for our task." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.585, + 0.87, + 0.718 + ], + "angle": 0, + "content": "Training Data Configuration. Since ground-truth faces are available during training, we train another variant by using the ground-truth face image as the inner loop supervision. Note that the MaskNet is trained together with the SR model, and we omitted it when training the version using ground-truth faces as inner loop supervision since the optimal solution should be an all-one mask. As shown in Tab. 3, the performance decreases by a large margin compared to MetaF2N, which is attributed to the gaps in the inner loop supervision between the training and inference phases." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.721, + 0.871, + 0.827 + ], + "angle": 0, + "content": "Inner Loop Supervision Scheme. Since there are often multiple faces in a single image, as a natural extension of our method, it is intuitive to apply multiple faces to stabilize the fine-tuning process. Therefore, we also explore the inner loop supervision scheme based on another 1,000 images sampled from the in-the-wild version of FFHQ [21] with multiple faces. As shown in Tab. 4, using patches of multiple faces can slightly benefit the final performance." + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.832, + 0.871, + 0.845 + ], + "angle": 0, + "content": "Influence of Different Face Hallucination Network. To" + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.876, + 0.507, + 0.887 + ], + "angle": 0, + "content": "13040" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.117, + 0.146, + 0.46, + 0.529 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.173, + 0.53, + 0.401, + 0.543 + ], + "angle": 0, + "content": "Figure 5: Visual results of MaskNet." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.552, + 0.473, + 0.695 + ], + "angle": 0, + "content": "find the influence of different face hallucination network for the MetaF2N, we conduct an ablation study by replacing GPEN [57] with CodeFormer [63] during training and testing. As shown in Tab. 5, one can see that our MetaF2N shows satisfactory robustness with different face hallucination networks for both \\(\\mathrm{FFHQ}_{i\\bar{i}d}\\) and \\(\\mathrm{FFHQ}_{\\mathrm{ood}}\\). Although the CodeFormer [63] can restore higher quality faces compared with GPEN [57], our MaskNet minish the gap through allocating weights for each pixel of restored faces, which enhances the robustness of MetaF2N for different face hallucination networks." + }, + { + "type": "text", + "bbox": [ + 0.102, + 0.709, + 0.472, + 0.762 + ], + "angle": 0, + "content": "Table 3: Ablation study on the training scheme regarding data configuration and the MaskNet. Train/Test Faces denote the setting of inner-loop supervision during the training and inference stages." + }, + { + "type": "table", + "bbox": [ + 0.108, + 0.764, + 0.468, + 0.839 + ], + "angle": 0, + "content": "
MaskNetTrain FacesTest FacesPSNR↑LPIPS↓FID↓NIQE↓
-GTGPEN25.680.28546.964.08
-GPENGPEN26.170.28447.894.21
MaskNetNRGPENGPEN26.070.28447.974.09
MaskNetDRGPENGPEN26.130.28145.223.81
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.151, + 0.869, + 0.19 + ], + "angle": 0, + "content": "Table 4: Ablation study on inner loop supervision, which is performed on 1,000 images with multiple faces (\\(\\sim\\)2.3 faces/image) from the in-the-wild version of FFHQ [21]." + }, + { + "type": "table", + "bbox": [ + 0.509, + 0.192, + 0.859, + 0.271 + ], + "angle": 0, + "content": "
# of FacesData FormPSNR↑LPIPS↓FID↓NIQE↓
SingleFull image25.730.28842.963.63
Single32 patches25.770.28842.893.65
Multiple32 patches in total25.790.28742.853.65
Multiple32 patches per face25.790.28742.813.65
" + }, + { + "type": "table_caption", + "bbox": [ + 0.5, + 0.28, + 0.868, + 0.307 + ], + "angle": 0, + "content": "Table 5: Ablation study on face hallucination networks which is performed on both \\(\\mathrm{FFHQ}_{iid}\\) and \\(\\mathrm{FFHQ}_{ood}\\)." + }, + { + "type": "table", + "bbox": [ + 0.505, + 0.308, + 0.869, + 0.39 + ], + "angle": 0, + "content": "
TestsetsTrain FacesTest FacesPSNR↑LPIPS↓FID↓NIQE↓
FFHQidGPENGPEN26.130.28145.223.81
CodeFormerCodeFormer26.100.27845.833.83
FFHQoodGPENGPEN25.490.28445.074.22
CodeFormerCodeFormer25.510.28144.584.24
" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.412, + 0.748, + 0.426 + ], + "angle": 0, + "content": "5.5. Limitations and Future Work" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.434, + 0.869, + 0.566 + ], + "angle": 0, + "content": "Since our MetaF2N is trained in a MAML framework, the performance before fine-tuning is unconstrained. As such, our model requires fine-tuning with the contained faces for one or multiple steps, making it cannot be directly applied if no faces exist in real-world low-quality images, which limits the application scenarios of our method. In the future, we plan to solve this problem by collecting a real-world low-quality training set and providing a better initialization of parameters that can be used to achieve satisfactory performance even without fine-tuning." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.583, + 0.611, + 0.597 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.607, + 0.87, + 0.75 + ], + "angle": 0, + "content": "In this paper, we proposed a MetaF2N framework for face-guided blind image SR. The MetaF2N improves the practicability of leveraging blind face restoration for processing image-specific degradations. A MaskNet is deployed to predict the loss weights for different positions considering the gaps between recovered faces and potential ground-truth ones. The proposed MetaF2N achieves superior performance on synthetic datasets with both independent and identically distributed and out-of-distribution degradations compared to training sets. The effectiveness is also validated on the collected real-world dataset." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.768, + 0.651, + 0.784 + ], + "angle": 0, + "content": "Acknowledgement" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.792, + 0.87, + 0.845 + ], + "angle": 0, + "content": "This work was supported in part by the National Key Research and Development Program of China under Grant No. 2022YFA1004103 and the National Natural Science Foundation of China (NSFC) under Grant No. U19A2073." + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.876, + 0.505, + 0.887 + ], + "angle": 0, + "content": "13041" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.105, + 0.147, + 0.194, + 0.161 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.112, + 0.169, + 0.471, + 0.217 + ], + "angle": 0, + "content": "[1] Eirikur Agustsson and Radu Timofte. NTIRE 2017 challenge on single image super-resolution: Dataset and study. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 126-135, 2017. 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.112, + 0.218, + 0.471, + 0.253 + ], + "angle": 0, + "content": "[2] Shahrukh Athar and Zhou Wang. Degraded reference image quality assessment. IEEE Transactions on Image Processing, pages 822-837, 2023. 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.112, + 0.255, + 0.471, + 0.3 + ], + "angle": 0, + "content": "[3] Mikołaj Binkowski, Danica J Sutherland, Michael Arbel, and Arthur Gretton. Demystifying mmd gans. In International Conference on Learning Representations, pages 1-36, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.112, + 0.302, + 0.471, + 0.326 + ], + "angle": 0, + "content": "[4] Will Brennan. BlurDetection2. https://github.com/WillBrennan/BlurDetection2, 2017.6" + }, + { + "type": "ref_text", + "bbox": [ + 0.112, + 0.327, + 0.471, + 0.385 + ], + "angle": 0, + "content": "[5] Jianrui Cai, Hui Zeng, Hongwei Yong, Zisheng Cao, and Lei Zhang. Toward real-world single image super-resolution: A new benchmark and a new model. In IEEE International Conference on Computer Vision, pages 3086-3095, 2019. 1, 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.112, + 0.387, + 0.471, + 0.445 + ], + "angle": 0, + "content": "[6] Kelvin CK Chan, Xintao Wang, Xiangyu Xu, Jinwei Gu, and Chen Change Loy. GLEAN: Generative latent bank for large-factor image super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 14245-14254, 2021. 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.112, + 0.447, + 0.471, + 0.507 + ], + "angle": 0, + "content": "[7] Chaofeng Chen, Xiaoming Li, Lingbo Yang, Xianhui Lin, Lei Zhang, and Kwan-Yee K Wong. Progressive semantic-aware style transformation for blind face restoration. In IEEE Conference on Computer Vision and Pattern Recognition, pages 11896-11905, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.112, + 0.508, + 0.471, + 0.554 + ], + "angle": 0, + "content": "[8] Chang Chen, Zhiwei Xiong, Xinmei Tian, Zheng-Jun Zha, and Feng Wu. Camera lens super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 1652-1660, 2019. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.112, + 0.556, + 0.471, + 0.603 + ], + "angle": 0, + "content": "[9] Honggang Chen, Xiaohai He, Linbo Qing, Yuanyuan Wu, Chao Ren, Ray E Sheriff, and Ce Zhu. Real-world single image super-resolution: A brief review. Information Fusion, pages 124-145, 2022. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.604, + 0.471, + 0.652 + ], + "angle": 0, + "content": "[10] Mohammad Emad, Maurice Peemen, and Henk Corporaal. DualSR: Zero-shot dual learning for real-world superresolution. In IEEE Winter Conference on Applications of Computer Vision, pages 1630-1639, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.653, + 0.471, + 0.699 + ], + "angle": 0, + "content": "[11] Chelsea Finn, Pieter Abbeel, and Sergey Levine. Model-agnostic meta-learning for fast adaptation of deep networks. In International Conference on Machine Learning, pages 1126–1135, 2017. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.7, + 0.471, + 0.747 + ], + "angle": 0, + "content": "[12] Manuel Fritsche, Shuhang Gu, and Radu Timofte. Frequency separation for real-world super-resolution. In IEEE International Conference on Computer Vision Workshops, pages 3599-3608, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.748, + 0.471, + 0.796 + ], + "angle": 0, + "content": "[13] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. Communications of the ACM, pages 139–144, 2020. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.797, + 0.471, + 0.843 + ], + "angle": 0, + "content": "[14] Erin Grant, Chelsea Finn, Sergey Levine, Trevor Darrell, and Thomas Griffiths. Recasting gradient-based meta-learning as hierarchical bayes. arXiv preprint arXiv:1801.08930, 2018. 3" + }, + { + "type": "list", + "bbox": [ + 0.106, + 0.169, + 0.471, + 0.843 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.15, + 0.869, + 0.197 + ], + "angle": 0, + "content": "[15] Jinjin Gu, Hannan Lu, Wangmeng Zuo, and Chao Dong. Blind super-resolution with iterative kernel correction. In IEEE Conference on Computer Vision and Pattern Recognition, pages 1604-1613, 2019. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.198, + 0.869, + 0.257 + ], + "angle": 0, + "content": "[16] Yuchao Gu, Xintao Wang, Liangbin Xie, Chao Dong, Gen Li, Ying Shan, and Ming-Ming Cheng. VQFR: Blind face restoration with vector-quantized dictionary and parallel decoder. In European Conference on Computer Vision, pages 126–143, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.258, + 0.869, + 0.317 + ], + "angle": 0, + "content": "[17] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in Neural Information Processing Systems, pages 6626-6637, 2017. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.318, + 0.868, + 0.365 + ], + "angle": 0, + "content": "[18] Yan Huang, Shang Li, Liang Wang, Tieniu Tan, et al. Unfolding the alternating optimization for blind super resolution. Advances in Neural Information Processing Systems, pages 5632-5643, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.365, + 0.868, + 0.424 + ], + "angle": 0, + "content": "[19] Xiaozhong Ji, Yun Cao, Ying Tai, Chengjie Wang, Jilin Li, and Feiyue Huang. Real-world super-resolution via kernel estimation and noise injection. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 466-467, 2020. 2, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.425, + 0.868, + 0.496 + ], + "angle": 0, + "content": "[20] Hamid Reza Vaezi Joze, Ilya Zharkov, Karlton Powell, Carl Ringler, Luming Liang, Andy Roulston, Moshe Lutz, and Vivek Pradeep. ImagePairs: Realistic super resolution dataset via beam splitter camera rig. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 518-519, 2020. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.497, + 0.868, + 0.544 + ], + "angle": 0, + "content": "[21] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In IEEE Conference on Computer Vision and Pattern Recognition, pages 4401-4410, 2019. 2, 6, 8, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.545, + 0.868, + 0.604 + ], + "angle": 0, + "content": "[22] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of stylegan. In IEEE Conference on Computer Vision and Pattern Recognition, pages 8110-8119, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.605, + 0.868, + 0.639 + ], + "angle": 0, + "content": "[23] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.64, + 0.868, + 0.687 + ], + "angle": 0, + "content": "[24] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E Hinton. Imagenet classification with deep convolutional neural networks. Communications of the ACM, pages 84-90, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.688, + 0.868, + 0.736 + ], + "angle": 0, + "content": "[25] Royson Lee, Rui Li, Stylianos I Venieris, Timothy Hospedales, Ferenc Huszár, and Nicholas D Lane. Metalearned kernel for blind super-resolution kernel estimation. arXiv preprint arXiv:2212.07886, 2022. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.737, + 0.868, + 0.796 + ], + "angle": 0, + "content": "[26] Xiaoming Li, Chaofeng Chen, Xianhui Lin, Wangmeng Zuo, and Lei Zhang. From face to natural image: Learning real degradation for blind image super-resolution. In European Conference on Computer Vision, pages 376-392, 2022. 1, 3, 4, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.797, + 0.868, + 0.845 + ], + "angle": 0, + "content": "[27] Xiaoming Li, Chaofeng Chen, Shangchen Zhou, Xianhui Lin, Wangmeng Zuo, and Lei Zhang. Blind face restoration via deep multi-scale component dictionaries. In European Conference on Computer Vision, pages 399-415, 2020. 3" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.15, + 0.869, + 0.845 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.876, + 0.506, + 0.887 + ], + "angle": 0, + "content": "13042" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.105, + 0.149, + 0.473, + 0.21 + ], + "angle": 0, + "content": "[28] Xiaoming Li, Wenyu Li, Dongwei Ren, Hongzhi Zhang, Meng Wang, and Wangmeng Zuo. Enhanced blind face restoration with multi-exemplar images and adaptive spatial feature fusion. In IEEE Conference on Computer Vision and Pattern Recognition, pages 2706-2715, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.105, + 0.211, + 0.472, + 0.259 + ], + "angle": 0, + "content": "[29] Xiaoming Li, Ming Liu, Yuting Ye, Wangmeng Zuo, Liang Lin, and Ruigang Yang. Learning warped guidance for blind face restoration. In European Conference on Computer Vision, pages 272-289, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.26, + 0.472, + 0.307 + ], + "angle": 0, + "content": "[30] Xiaoming Li, Shiguang Zhang, Shangchen Zhou, Lei Zhang, and Wangmeng Zuo. Learning dual memory dictionaries for blind face restoration. IEEE Transactions on Pattern Analysis and Machine Intelligence, pages 1-13, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.308, + 0.471, + 0.357 + ], + "angle": 0, + "content": "[31] Xiaoming Li, Wangmeng Zuo, and Chen Change Loy. Learning generative structure prior for blind text image super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 10103-10113, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.358, + 0.472, + 0.393 + ], + "angle": 0, + "content": "[32] Weixin Liang, Zixuan Liu, and Can Liu. Dawson: A domain adaptive few shot generation framework. arXiv preprint arXiv:2001.00576, 2020. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.395, + 0.472, + 0.442 + ], + "angle": 0, + "content": "[33] Anran Liu, Yihao Liu, Jinjin Gu, Yu Qiao, and Chao Dong. Blind image super-resolution: A survey and beyond. IEEE Transactions on Pattern Analysis and Machine Intelligence, pages 1-19, 2022. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.444, + 0.471, + 0.49 + ], + "angle": 0, + "content": "[34] Ziwei Liu, Ping Luo, Xiaogang Wang, and Xiaou Tang. Deep learning face attributes in the wild. In IEEE International Conference on Computer Vision, pages 3730-3738, 2015. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.492, + 0.472, + 0.551 + ], + "angle": 0, + "content": "[35] Kede Ma, Zhengfang Duanmu, Qingbo Wu, Zhou Wang, Hongwei Yong, Hongliang Li, and Lei Zhang. Waterloo exploration database: New challenges for image quality assessment models. IEEE Transactions on Image Processing, pages 1004-1016, 2016. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.552, + 0.471, + 0.612 + ], + "angle": 0, + "content": "[36] Sachit Menon, Alexandru Damian, Shijia Hu, Nikhil Ravi, and Cynthia Rudin. PULSE: Self-supervised photo upsampling via latent space exploration of generative models. In IEEE Conference on Computer Vision and Pattern Recognition, pages 2437-2445, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.613, + 0.472, + 0.65 + ], + "angle": 0, + "content": "[37] Nikhil Mishra, Mostafa Rohaninejad, Xi Chen, and Pieter Abbeel. A simple neural attentive meta-learner. arXiv preprint arXiv:1707.03141, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.651, + 0.471, + 0.686 + ], + "angle": 0, + "content": "[38] Anish Mittal, Rajiv Soundararajan, and Alan C Bovik. Making a \"completely blind\" image quality analyzer. IEEE Signal Processing Letters, pages 209-212, 2012. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.688, + 0.472, + 0.746 + ], + "angle": 0, + "content": "[39] Chong Mou, Yanze Wu, Xintao Wang, Chao Dong, Jian Zhang, and Ying Shan. Metric learning based interactive modulation for real-world super-resolution. In European Conference on Computer Vision, pages 723-740, 2022. 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.748, + 0.471, + 0.796 + ], + "angle": 0, + "content": "[40] Boris Oreshkin, Pau Rodríguez López, and Alexandre Lacoste. TADAM: Task dependent adaptive metric for improved few-shot learning. Advances in Neural Information Processing Systems, pages 719-729, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.797, + 0.472, + 0.845 + ], + "angle": 0, + "content": "[41] Seobin Park, Jinsu Yoo, Donghyeon Cho, Jiwon Kim, and Tae Hyun Kim. Fast adaptation to super-resolution networks via meta-learning. In European Conference on Computer Vision, pages 754-769, 2020. 3, 4" + }, + { + "type": "list", + "bbox": [ + 0.105, + 0.149, + 0.473, + 0.845 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.15, + 0.869, + 0.197 + ], + "angle": 0, + "content": "[42] Assaf Shocher, Nadav Cohen, and Michal Irani. \"zero-shot\" super-resolution using deep internal learning. In IEEE Conference on Computer Vision and Pattern Recognition, pages 3118-3126, 2018. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.2, + 0.869, + 0.247 + ], + "angle": 0, + "content": "[43] Jae Woong Soh, Sunwoo Cho, and Nam Ik Cho. Meta-transfer learning for zero-shot super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 3516-3525, 2020. 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.249, + 0.868, + 0.295 + ], + "angle": 0, + "content": "[44] Qianru Sun, Yaoyao Liu, Tat-Seng Chua, and Bernt Schiele. Meta-transfer learning for few-shot learning. In IEEE Conference on Computer Vision and Pattern Recognition, pages 403-412, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.297, + 0.868, + 0.356 + ], + "angle": 0, + "content": "[45] Flood Sung, Yongxin Yang, Li Zhang, Tao Xiang, Philip HS Torr, and Timothy M Hospedales. Learning to compare: Relation network for few-shot learning. In IEEE Conference on Computer Vision and Pattern Recognition, pages 1199-1208, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.358, + 0.868, + 0.417 + ], + "angle": 0, + "content": "[46] Radu Timofte, Eirikur Agustsson, Luc Van Gool, Ming-Hsuan Yang, and Lei Zhang. NTIRE 2017 challenge on single image super-resolution: Methods and results. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 114-125, 2017. 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.419, + 0.868, + 0.455 + ], + "angle": 0, + "content": "[47] Dmitry Ulyanov, Andrea Vedaldi, and Victor Lempitsky. Deep image prior. In IEEE Conference on Computer Vision and Pattern Recognition, pages 9446-9454, 2018. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.456, + 0.868, + 0.503 + ], + "angle": 0, + "content": "[48] Oriol Vinyals, Charles Blundell, Timothy Lillicrap, Daan Wierstra, et al. Matching networks for one shot learning. Advances in Neural Information Processing Systems, pages 3630-3638, 2016. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.505, + 0.868, + 0.564 + ], + "angle": 0, + "content": "[49] Longguang Wang, Yingqian Wang, Xiaoyu Dong, Qingyu Xu, Jungang Yang, Wei An, and Yulan Guo. Unsupervised degradation representation learning for blind superresolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 10581-10590, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.565, + 0.868, + 0.613 + ], + "angle": 0, + "content": "[50] Xintao Wang, Yu Li, Honglun Zhang, and Ying Shan. Towards real-world blind face restoration with generative facial prior. In IEEE Conference on Computer Vision and Pattern Recognition, pages 9168-9178, 2021. 1, 3, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.614, + 0.868, + 0.662 + ], + "angle": 0, + "content": "[51] Xintao Wang, Liangbin Xie, Chao Dong, and Ying Shan. Real-ESRGAN: Training real-world blind super-resolution with pure synthetic data. In IEEE International Conference on Computer Vision, pages 1905–1914, 2021. 1, 2, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.663, + 0.868, + 0.722 + ], + "angle": 0, + "content": "[52] Xintao Wang, Ke Yu, Chao Dong, and Chen Change Loy. Recovering realistic texture in image super-resolution by deep spatial feature transform. In IEEE Conference on Computer Vision and Pattern Recognition, pages 606-615, 2018. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.724, + 0.868, + 0.782 + ], + "angle": 0, + "content": "[53] Xintao Wang, Ke Yu, Shixiang Wu, Jinjin Gu, Yihao Liu, Chao Dong, Yu Qiao, and Chen Change Loy. ESRGAN: Enhanced super-resolution generative adversarial networks. In European Conference on Computer Vision Workshops, pages 63-79, 2018. 2, 4, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.785, + 0.868, + 0.845 + ], + "angle": 0, + "content": "[54] Zhouxia Wang, Jiawei Zhang, Runjian Chen, Wenping Wang, and Ping Luo. RestoreFormer: High-quality blind face restoration from undegraded key-value pairs. In IEEE Conference on Computer Vision and Pattern Recognition, pages 17491-17500, 2022. 3" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.15, + 0.869, + 0.845 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.466, + 0.876, + 0.505, + 0.887 + ], + "angle": 0, + "content": "13043" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.105, + 0.149, + 0.471, + 0.209 + ], + "angle": 0, + "content": "[55] Pengxu Wei, Ziwei Xie, Hannan Lu, Zongyuan Zhan, Qixiang Ye, Wangmeng Zuo, and Liang Lin. Component divide-and-conquer for real-world image super-resolution. In European Conference on Computer Vision, pages 101-117, 2020. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.105, + 0.211, + 0.472, + 0.258 + ], + "angle": 0, + "content": "[56] Shuo Yang, Ping Luo, Chen Change Loy, and Xiaou Tang. Wider face: A face detection benchmark. In IEEE Conference on Computer Vision and Pattern Recognition, pages 5525-5533, 2016. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.26, + 0.471, + 0.307 + ], + "angle": 0, + "content": "[57] Tao Yang, Peiran Ren, Xuansong Xie, and Lei Zhang. Gan prior embedded network for blind face restoration in the wild. In IEEE Conference on Computer Vision and Pattern Recognition, pages 672-681, 2021. 1, 3, 4, 5, 7, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.309, + 0.471, + 0.368 + ], + "angle": 0, + "content": "[58] Yuan Yuan, Siyuan Liu, Jiawei Zhang, Yongbing Zhang, Chao Dong, and Liang Lin. Unsupervised image superresolution using cycle-in-cycle generative adversarial networks. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 701-710, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.369, + 0.471, + 0.416 + ], + "angle": 0, + "content": "[59] Kai Zhang, Jingyun Liang, Luc Van Gool, and Radu Timofte. Designing a practical degradation model for deep blind image super-resolution. In IEEE International Conference on Computer Vision, pages 4791-4800, 2021. 1, 2, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.418, + 0.471, + 0.475 + ], + "angle": 0, + "content": "[60] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In IEEE Conference on Computer Vision and Pattern Recognition, pages 586-595, 2018. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.478, + 0.471, + 0.524 + ], + "angle": 0, + "content": "[61] Xuaner Zhang, Qifeng Chen, Ren Ng, and Vladlen Koltun. Zoom to learn, learn to zoom. In IEEE Conference on Computer Vision and Pattern Recognition, pages 3762-3770, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.527, + 0.471, + 0.585 + ], + "angle": 0, + "content": "[62] Heliang Zheng, Huan Yang, Jianlong Fu, Zheng-Jun Zha, and Jiebo Luo. Learning conditional knowledge distillation for degraded-reference image quality assessment. In IEEE International Conference on Computer Vision, pages 10242-10251, 2021. 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.588, + 0.471, + 0.633 + ], + "angle": 0, + "content": "[63] Shangchen Zhou, Kelvin CK Chan, Chongyi Li, and Chen Change Loy. Towards robust blind face restoration with codebook lookup transformer. arXiv preprint arXiv:2206.11253, 2022. 1, 3, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.106, + 0.636, + 0.471, + 0.695 + ], + "angle": 0, + "content": "[64] Feida Zhu, Junwei Zhu, Wenqing Chu, Xinyi Zhang, Xiaozhong Ji, Chengjie Wang, and Ying Tai. Blind face restoration via integrating face shape and generative priors. In IEEE Conference on Computer Vision and Pattern Recognition, pages 7662-7671, 2022. 3, 4" + }, + { + "type": "list", + "bbox": [ + 0.105, + 0.149, + 0.472, + 0.695 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.467, + 0.876, + 0.505, + 0.887 + ], + "angle": 0, + "content": "13044" + } + ] +] \ No newline at end of file diff --git a/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/ed6327a3-66bd-4260-9c23-011c9182cd69_origin.pdf b/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/ed6327a3-66bd-4260-9c23-011c9182cd69_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..33d30109bad0e39c9c9bb8e0d1afff70b2839eb0 --- /dev/null +++ b/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/ed6327a3-66bd-4260-9c23-011c9182cd69_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:cfe0d5a1118b498f264c0e97ddef567dc2dbb3dd94524671e99d4626a5ea6eba +size 1341111 diff --git a/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/full.md b/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/full.md new file mode 100644 index 0000000000000000000000000000000000000000..0bce5c7342b8c68a93899763124fa345f7360c43 --- /dev/null +++ b/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/full.md @@ -0,0 +1,446 @@ +# MetaF2N: Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces + +Zhicun Yin $^{1}$ Ming Liu $^{1(\boxtimes)}$ Xiaoming Li $^{1}$ Hui Yang $^{2}$ + +Longan Xiao2 Wangmeng Zuo1,3 + +$^{1}$ Harbin Institute of Technology $^{2}$ Shanghai Transsion Co, Ltd $^{3}$ Peng Cheng Laboratory + +cszcyin@outlook.com, csmliu@outlook.com, csxml@gmail.com, wmzuo@hit.edu.cn + +# Abstract + +Due to their highly structured characteristics, faces are easier to recover than natural scenes for blind image super-resolution. Therefore, we can extract the degradation representation of an image from the low-quality and recovered face pairs. Using the degradation representation, realistic low-quality images can then be synthesized to fine-tune the super-resolution model for the real-world low-quality image. However, such a procedure is time-consuming and laborious, and the gaps between recovered faces and the ground-truths further increase the optimization uncertainty. To facilitate efficient model adaptation towards image-specific degradations, we propose a method dubbed MetaF2N, which leverages the contained Faces to fine-tune model parameters for adapting to the whole Natural image in a Meta-learning framework. The degradation extraction and low-quality image synthesis steps are thus circumvented in our MetaF2N, and it requires only one fine-tuning step to get decent performance. Considering the gaps between the recovered faces and groundtruths, we further deploy a MaskNet for adaptively predicting loss weights at different positions to reduce the impact of low-confidence areas. To evaluate our proposed MetaF2N, we have collected a real-world low-quality dataset with one or multiple faces in each image, and our MetaF2N achieves superior performance on both synthetic and real-world datasets. Source code, pre-trained models, and collected datasets are available at https://github.com/yinzhicun/MetaF2N. + +# 1. Introduction + +With the development of dataset construction, network design, and many other relevant methods, blind image super-resolution (SR) [9, 33] has acquired enormous progress in recent years. To construct pairwise low-/high-quality samples for training the image SR models, typically + +one can capture low- and high-quality pairs by adjusting the focal length of cameras [5, 55, 61] and shooting distance [8], or synthesize low-quality images via degradation modeling [26, 51, 59]. However, these methods can only cover a limited and biased range of degradations, which is insufficient for real-world applications. Besides, most existing blind image SR methods [51, 59] train a static model for all testing scenarios, greatly limiting their flexibility and generalization ability. + +In order to break the restriction of limited training sets, self-supervised learning has been introduced to train a model for each low-quality image, without requiring pairwise ground-truths [10, 42, 47]. Although these methods exhibit a great deal of flexibility, they largely rely on certain priors or assumptions, showing inferior image SR performance. Recently, Li et al. [26] reached a better compromise on the requirement of ground-truths and proposed ReDegNet by leveraging the faces contained in natural images. In specific, the face regions in a real-world low-quality natural image are processed via blind face SR methods [36, 50, 57, 63], which have achieved appealing results thanks to the highly structured characteristics of faces. Then, the low-quality and recovered face pairs can be utilized to model the degradations in the image. Finally, more low-quality images are synthesized with the degradation representations for fine-tuning the SR model. With the above design, ReDegNet [26] is flexible to process a single image or a batch of images with diverse degradations. + +Although ReDegNet [26] achieves superior SR performance, especially in specific scenarios (i.e., fine-tuning with faces within the test image), there are still several limitations. On the one hand, the training procedure is time-consuming and computationally intensive, where the modules for degradation representation extraction and low-quality image synthesis are jointly optimized. Furthermore, when the model is intended to deal with a single low-quality image, it is difficult to determine when to terminate the training process for avoiding under-fitting or over-fitting. + +On the other hand, even though the faces processed by the blind face restoration methods show appealing quality, there inevitably exist gaps between the recovered faces and the real ground-truths. Such gaps may affect the degradation representation accuracy and further hamper the training of the SR model. These problems have a large impact on the SR performance, especially when the model is fine-tuned for image-specific super-resolution. + +To remedy the aforementioned problems regarding training efforts and data gaps, we propose an efficient and effective method dubbed MetaF2N. In specific, the SR model directly fine-tunes the parameters from the low-quality and recovered face pairs, then uses the fine-tuned parameters to process the whole natural image. As such, the cumbersome degradation extraction and low-quality image synthesis steps are circumvented in our method, which avoids the interference of degradation modeling errors. In order to stabilize and accelerate the fine-tuning process during inference, we adopt the model-agnostic meta-learning [11] framework in the training phase, resulting in a much more practical model adaptation procedure that can be finished in a single fine-tuning step. + +Additionally, considering the gaps between low-quality faces and that processed by blind face restoration methods, we argue that treating all pixels equally will magnify the effect of the errors. Therefore, we further deploy a MaskNet, which adaptively predicts loss weights for different positions, to fulfill that the recovered face regions more similar to the ground-truths are assigned with higher loss weights. Ideally, the weight map should be extracted from the recovered faces and the ground-truths. Unfortunately, the ground-truths are unavailable during inference. Considering that predicting the loss weight map is similar to the image quality assessment (IQA) task, following the idea of degraded-reference IQA methods [2, 62], the MaskNet instead takes the low-quality and recovered faces as input. According to our observation, typically the areas closer to the ground-truth are assigned with larger weights and vice versa, which is consistent with the intuitions. + +For evaluating the proposed MetaF2N, we have constructed several synthetic datasets based on FFHQ [21] and CelebA [34]. To further show the effectiveness under real-world scenarios, we have also collected a real-world low-quality image dataset from the Internet and existing datasets, namely RealFaces200 (RF200), which contains a single face or multiple faces in each image. Extensive experiments show that our MetaF2N achieves superior performance on both synthetic and real-world datasets. + +In summary, the contribution of this paper includes, + +- We propose an efficient and effective method dubbed MetaF2N for blind image super-resolution, which takes advances of blind face restoration models and learns model adaptation from the face regions with + +only one fine-tuning step. + +- Considering that the gaps between faces recovered by blind face restoration methods and the ground-truth ones may result in an inaccurate degradation modeling, a MaskNet is introduced for confidence prediction to mitigate the effect of the gaps. +- A real-world low-quality image dataset with one or multiple faces in each image is collected, which will be helpful for face-guided blind image super-resolution. + +# 2. Related Work + +Recent efforts on blind image SR are mainly devoted to network design and data construction. We recommend [9, 33] for a comprehensive review of blind image SR, and focus on the most relevant methods of data construction, which are orthogonal to network design. We also briefly review recent advances in blind face restoration and meta-learning, which settle the foundation of this work. + +# 2.1. Blind Image Super-Resolution + +Pairwise Data. Recent methods have made great efforts towards pairwise datasets that cover a wider range of real-world degradations and are better aligned. The most intuitive way is to collect pairwise samples. For example, Chen et al. [8] collected a City100 dataset by a DSLR and a smartphone via focal length and shooting distance adjustment, respectively. Since City100 was captured via postcards ignoring the geometries, Cai et al. [5] and Wei et al. [55] proposed to capture image pairs in real-world scenes and collected two datasets RealSR and DRealSR. Joze et al. [20] instead captured a dataset ImagePairs by embedding two cameras with different resolutions into a beam splitter. Another approach is to synthesize low-quality images from high-quality ones. Early methods [15, 18, 19, 53] utilized classical degradation models composed of blur, down-sampling, noise, etc., which are insufficient to model the real-world degradations. Zhang et al. [59] and Wang et al. [51] proposed to mimic real-world degradations via random combinations of different degradations. Albeit their progress on general image SR, these methods still cover a limited and biased range of real-world degradations. + +Unpaired Data. For better utilizing unpaired low-quality images that are easier to collect, some methods [12, 49, 58] proposed to extract the degradation representations or directly learn low-quality image synthesis in an unsupervised manner. Some methods [42, 47] utilized the texture recurrence across different scales or the priors embraced in the model learning process, and achieved image-specific blind image super-resolution in a self-supervised scheme. Purely relying on the unpaired samples or solely the low-quality ones, these methods may cover more degradations yet have + +unsatisfactory performance in most cases. As a compromise, Li et al. [26] utilized the highly structured faces in real-world low-quality images, and extracted degradation representations from the low-quality faces and their counterparts recovered by blind face restoration methods. In this work, we take a step forward to solve the problems of Li et al. [26] and propose a MetaF2N framework for effective blind image SR of LR natural images containing faces. + +# 2.2. Blind Face Restoration + +The diverse structures and complicated degradation jointly exacerbate the difficulties of blind natural image SR. In contrast, recent methods tend to leverage the structure information of specific images (e.g., faces [27-30, 57, 63] and text [31]), which have exhibited superior performance. Li et al. [28, 29] suggested using high-quality image(s) of the same person to provide personalized guidance. More general face restoration methods focused on constructing dictionaries [16, 27, 30, 54], semantic maps [7], or codebooks [63]. Recently, the generative structure prior based methods [6, 50, 57, 64] leveraged the representative pretrained StyleGAN models [22] and showed tremendous improvement in restoring fine-grained textures. Compared with natural images, these methods showed great generalization abilities, even in the presence of unknown degradations. This property has motivated us to employ face images on the inner loop of meta-learning to benefit the optimization toward better natural image SR. + +# 2.3. Image Super-Resolution with Meta-Learning + +Meta-learning aims to learn adaptation to new domains or tasks by leveraging existing ones, which has demonstrated excellent generalization ability in many tasks [11, 14, 37, 40, 44, 45, 48]. Early works like MZSR [43] and MLSR [41] utilized meta-learning techniques to obtain a better initialization of model parameters that can be efficiently adapted to new low-quality images. Meta-KernelGAN [25] utilized meta-learning for efficient kernel estimation, which can be combined with non-blind SR methods. As one can see, MZSR [43] and MLSR [41] heavily rely on known degradations to construct inner loop supervisions, while Meta-KernelGAN is also restricted due to that the degradation representations formulated by kernels cannot well describe many real-world degradations. In this work, we adopt face regions as inner loop supervision and get rid of explicit degradation representations, which is more practical for real-world scenarios. + +# 3. Preliminary + +For efficiently utilizing the generalization ability of face restoration methods in blind image SR and achieving flexibility on image-specific degradations, we have designed our + +MetaF2N using the model-agnostic meta-learning framework (MAML) [11]. In this section, we briefly introduce the meta-learning framework based on MAML, which will be helpful for understanding our method. + +Typically, a deep model $f$ is trained by a learning objective $\mathcal{L}$ , which is directly dependent on the purpose of the task (e.g., $\ell_1$ loss for fidelity in image SR tasks), and the optimal parameter $\theta^*$ is obtained via + +$$ +\theta^ {*} = \arg \min _ {\theta} \mathcal {L} (f (\mathbf {x}; \theta), \mathbf {y}), \tag {1} +$$ + +where $\mathbf{x}$ and $\mathbf{y}$ are input and ground-truth. Intuitively, the objective of Eqn. (1) is to get a $\theta$ leading to the lowest $\mathcal{L}$ . + +Instead, MAML [11] aims to learn a parameter $\theta^{*}$ , which can be efficiently fine-tuned toward the test sample with one or several steps. Taking the one-step situation as an example, the learning objective can be written as + +$$ +\theta^ {*} = \arg \min _ {\theta} \sum_ {T _ {i} \sim p (T)} \mathcal {L} ^ {T _ {i}} \left(f (\mathbf {x}; \theta - \alpha \frac {\partial \mathcal {L} _ {i n} ^ {T _ {i}}}{\partial \theta}), \mathbf {y}\right), \tag {2} +$$ + +where $p(T),\mathcal{L}_{in}^{T_i}$ , and $\alpha$ respectively represent the distribution (or collection) of tasks, the inner loop loss function for the task $T_{i}$ , and learning rate for the inner loop. Here, we can regard $\theta -\alpha \frac{\partial\mathcal{L}_{in}^{T_i}}{\partial\theta}$ as a whole. Then, similar to Eqn. (1), the objective of Eqn. (2) can be interpreted as to get a $\theta$ leading to the lowest $\mathcal{L}^{T_i}$ after one back-propagation step w.r.t. $\mathcal{L}_{in}^{T_i}$ . In other words, a model trained under the MAML settings can adapt to new domains or tasks with a limited number of fine-tuning steps (i.e., $\theta -\alpha \frac{\partial\mathcal{L}_{in}^{T_i}}{\partial\theta})$ + +# 4. Method + +In this work, we aim to obtain a blind image SR model $f$ which can be efficiently adapted to process the degradation of a real-world low-quality image $\mathbf{I}_{LR}$ under the guidance of its face regions (denoted by $\mathbf{I}_{LR}^{\ominus}$ ) and the faces processed by blind face restoration methods (denoted by $\mathbf{I}_{BFR}^{\ominus}$ ). + +Considering the complex and wide-range degradations in real-world low-quality images, we take advantage of MAML to design our method for processing image-specific degradations. Then Eqn. (2) can be rewritten as, + +$$ +\theta^ {*} = \arg \min _ {\theta} \sum_ {T _ {i} \sim p (T)} \mathcal {L} ^ {T _ {i}} \left(f \left(\mathbf {I} _ {L R}; \theta - \alpha \frac {\partial \mathcal {L} _ {i n} ^ {T _ {i}}}{\partial \theta}\right), \mathbf {I}\right), \tag {3} +$$ + +where $p(T)$ is the distribution of different degradations, $T_{i}$ is the task for one specific degradation, $\theta$ is the parameter of $f$ and $\mathbf{I}$ denotes the ground-truth image. The design of $\mathcal{L}_{in}^{T_i}$ will be given in Sec. 4.1. + +# 4.1. Inner Loop Design + +One of the key factors of applying MAML [11] to blind image SR tasks is the design of $\mathcal{L}_{in}^{T_i}$ in Eqn. (3). Specifically, for adapting to the new degradation of an $\mathbf{I}_{LR}$ , the + +![](images/b7ef4561c43c31ea7a84af1464be0e372dac16294c2821e8a554c3a121114ce7.jpg) +Figure 1: Pipeline of the proposed MetaF2N framework. During inference, the inner loop updates the initial parameter $\theta$ via a back-propagation step (dotted blue line), and the obtained $\theta_{n}$ is used to process the whole natural image in the outer loop. For training, the parameter update indeed relies on the gradients of outer loop loss $\mathcal{L}^{T_i}$ w.r.t. the initial parameter $\theta$ and the MaskNet parameter $\theta_{\mathbf{m}}$ (dotted red line). For easier understanding, the steps of the pipeline (remarked by circled numbers) are introduced in Sec. 4.3. Please refer to Algorithms 1 and 2 for more details about the training and inference process. + +data for calculating $\mathcal{L}_{in}^{T_i}$ should have the same distribution as $\mathbf{I}_{LR}$ . For MAML-based non-blind image SR methods [41, 43], one can construct inner loop data by further down-sampling $\mathbf{I}_{LR}$ with the known degradation $d$ to get $\mathbf{I}_{LLR} = d(\mathbf{I}_{LR})$ . Then assuming the inner loop loss function to be $\ell_1$ , we can obtain $\mathcal{L}_{in}^{T_i} = \| f(\mathbf{I}_{LLR};\theta) - \mathbf{I}_{LR}\|_1$ . However, for blind image SR, it is almost impossible to get extra image pairs with the same degradation as $\mathbf{I}_{LR}$ since $d$ is unknown. + +Inspired by ReDegNet [26], which shows that faces can be utilized to extract the degradation representation for the whole image, we directly construct the inner loop data with the face regions. Thanks to the great generalization ability of blind face restoration methods [6,50,57,64], we are able to obtain a pseudo ground-truth for the face regions, which is denoted by $\mathbf{I}_{BFR}^{\ominus} = f_{BFR}(\mathbf{I}_{LR}^{\ominus};\theta_{BFR})$ , where $f_{BFR}$ is the blind face restoration model with pre-trained parameter $\theta_{BFR}$ . In this paper, we follow ReDegNet [26] and adopt GPEN [57] as $f_{BFR}$ . With the low-quality face regions $\mathbf{I}_{LR}^{\ominus}$ and the recovered $\mathbf{I}_{BFR}^{\ominus}$ , the inner loop loss function can be defined by + +$$ +\mathcal {L} _ {i n} ^ {T _ {i}} = \left\| f \left(\mathbf {I} _ {L R} ^ {\ominus}; \theta\right) - \mathbf {I} _ {B F R} ^ {\ominus} \right\| _ {1}. \tag {4} +$$ + +# 4.2. Adaptive Loss Weighting with MaskNet + +Despite the appealing visual quality of recent blind face restoration methods, there inevitably exist gaps between generated faces $\mathbf{I}_{BFR}^{\ominus}$ and ground-truth ones $\mathbf{I}^{\ominus}$ . For inaccurate regions, the degradation either explicitly (ReDeg-Net [26]) or implicitly (Our MetaF2N) described by the $(\mathbf{I}_{LR}^{\ominus},\mathbf{I}_{BFR}^{\ominus})$ pair also deviate from that by $(\mathbf{I}_{LR}^{\ominus},\mathbf{I}^{\ominus})$ . + +However, different regions of $\mathbf{I}_{BFR}^{\odot}$ are treated equally in Eqn. (4), which will have negative effect on the final results. As a remedy, we propose to predict loss weights adaptively for different regions via a MaskNet. With the weight map + +m generated by the MaskNet, Eqn. (4) can be rewritten as + +$$ +\mathcal {L} _ {i n} ^ {T _ {i}} = \left\| \mathbf {m} \cdot \left(f \left(\mathbf {I} _ {L R} ^ {\ominus}; \theta\right) - \mathbf {I} _ {B F R} ^ {\ominus}\right) \right\| _ {1}. \tag {5} +$$ + +Ideally, $\mathbf{m}$ should be generated from the $(\mathbf{I}_{BFR}^{\odot},\mathbf{I}^{\odot})$ pair. Unfortunately, $\mathbf{I}$ is unavailable for test samples, a possible solution is solely predicting from $\mathbf{I}_{BFR}^{\odot}$ , yet the improvement is marginal. Analogous to degraded-reference IQA [2, 62] which predicts IQA metrics from (input, output) pairs rather than (output, GT) pairs in full-reference IQA, we predict $\mathbf{m}$ from the $(\mathbf{I}_{LR}^{\odot},\mathbf{I}_{BFR}^{\odot})$ pair, i.e., + +$$ +\mathbf {m} = f _ {\mathbf {m}} \left(\mathbf {I} _ {L R} ^ {\prime}, \mathbf {I} _ {B F R} ^ {\prime}; \theta_ {\mathbf {m}}\right), \tag {6} +$$ + +where $f_{\mathbf{m}}$ is the MaskNet, which is a simple network composed of 8 convolution layers shown in Fig. 2. As further shown in the ablation studies, the degraded-reference solution in Eqn. (6) performs better than solely predicting from $\mathbf{I}_{BFR}^{\odot}$ . + +# 4.3. Overall Pipeline and Learning Objective + +With the inner loop designed in Eqn. (5), we can build the pipeline as shown in Fig. 1. In specific, given a low-quality image $\mathbf{I}_{LR}$ containing face regions denoted by $\mathbf{I}_{LR}^{\ominus}$ , we pass $\mathbf{I}_{LR}^{\ominus}$ through the SR network $f$ and obtain the inner loop result $\mathbf{I}_{SR}^{\ominus}$ . For a fair comparison against existing methods, we take the model of Real-ESRGAN [53] as the SR network, whose parameter is used to initialize the $\theta$ in the inner loop. To construct supervision for the inner loop, we use a pre-trained GPEN [57] model, whose parameter is kept fixed in our whole pipeline. Then we can obtain the weight map $\mathbf{m}$ following Eqn. (6), as well as the inner loop loss $\mathcal{L}_{in}^{T_i}$ following Eqn. (5), which can be used to generate a temporary parameter $\theta_{\mathrm{n}} = \theta -\alpha \frac{\partial\mathcal{L}_{in}^{T_i}}{\partial\theta}$ for processing the whole natural image in the outer loop, i.e., + +$$ +\mathbf {I} _ {S R} = f \left(\mathbf {I} _ {L R}; \theta_ {\mathbf {n}}\right) = f \left(\mathbf {I} _ {L R}; \theta - \alpha \frac {\partial \mathcal {L} _ {i n} ^ {T _ {i}}}{\partial \theta}\right) ⑥. \tag {7} +$$ + +Algorithm 1: Training Process of MetaF2N +Input: Distribution of different degradation restoration tasks $p(T)$ High-quality natural image dataset $\mathcal{D}_{HR}$ High-quality face dataset $\mathcal{D}_{\odot}$ Learning rates $\alpha ,\beta ,\gamma ,\eta$ Output: Model parameter $\theta ,\theta_{\mathbf{m}}$ 1 Initialize $f,D$ with $\theta ,\theta_{D}$ from Real-ESRGAN [51] 2 Initialize $f_{BFR}$ with $\theta_{BFR}$ from GPEN [57] 3 Random initialize $f_{\mathbf{m}}$ with $\theta_{\mathbf{m}}$ 4 for all training steps do 5 Sample batch of tasks $T_{i}\sim p(T)$ 6 for all $T_{i}$ do 7 Sample images $\mathbf{I},\mathbf{I}^{\odot}$ from $\mathcal{D}_{\mathcal{H}\mathcal{R}}$ and $\mathcal{D}_{\odot}$ 8 Create $\mathbf{I},\mathbf{I}_{LR},\mathbf{I}_{LR}^{\odot}$ of $T_{i}$ 9 $\mathbf{I}_{BFR}^{\odot} = f_{BFR}(\mathbf{I}_{LR}^{\odot};\theta_{BFR})$ m $= f_{\mathrm{m}}(\mathbf{I}_{LR}^{\odot},\mathbf{I}_{BFR}^{\odot};\theta_{\mathrm{m}})$ for 1 step of inner loop do 12 $\begin{array}{r}\mathcal{L}_{in}^{T_i} = ||\mathbf{m}\cdot (f(\mathbf{I}_{LR}^{\odot};\theta) - \mathbf{I}_{BFR}^{\odot})||_1\\ \theta_{\mathrm{n}}\gets \theta -\alpha \nabla_{\theta}\mathcal{L}_{in}^{T_i}(\theta) \end{array}$ end 15 $\mathbf{I}_{SR} = f(\mathbf{I}_{LR};\theta_{\mathbf{n}})$ 16 $\mathcal{L}^{T_i}$ is defined as Eqn. (13) 17 $\mathcal{L}_D^{T_i}$ is defined as Eqn. (11) end 19 $\theta \gets \theta -\beta \nabla_{\theta}\sum_{T_i\sim p(T)}\mathcal{L}^{T_i}$ 20 $\theta_{\mathrm{m}}\gets \theta_{\mathrm{m}} - \gamma \nabla_{\theta_{\mathrm{m}}}\sum_{T_i\sim p(T)}\mathcal{L}^{T_i}$ 21 $\theta_D\gets \theta_D - \eta \nabla_{\theta_D}\sum_{T_i\sim p(T)}\mathcal{L}_D^{T_i}$ 22 end + +Algorithm 2: Inference Process of MetaF2N +Input: LR test image $\mathbf{I}_{LR}$ Trained model parameter $\theta ,\theta_{\mathrm{m}}$ Pre-trained GPEN [57] parameter $\theta_{BFR}$ Fine-tuning steps $n$ and learning rate $\alpha$ Output: Super-resolved image $\mathbf{I}_{SR}$ 1 Initialize $f,f_{\mathbf{m}}$ with $\theta ,\theta_{\mathbf{m}}$ 2 Initialize $f_{BFR}$ with $\theta_{BFR}$ from GPEN [57] 3 Extract face regions $\mathbf{I}_{LR}^{\ominus}$ from $\mathbf{I}_{LR}$ 4 $\mathbf{I}_{BFR}^{\ominus} = f_{BFR}(\mathbf{I}_{LR}^{\ominus};\theta_{BFR})$ 5 $\mathbf{m} = f_{\mathbf{m}}(\mathbf{I}_{LR}^{\ominus},\mathbf{I}_{BFR}^{\ominus};\theta_{\mathbf{m}})$ 6 for n steps of inner loop do 7 $\begin{array}{rl}{\mathcal{L}_{in}} & {= \| \mathbf{m}\cdot (f(\mathbf{I}_{LR}^{\ominus};\theta) - \mathbf{I}_{BFR}^{\ominus})\| _1}\\ {\theta} & {\leftarrow \theta -\alpha \nabla_{\theta}\mathcal{L}_{in}(\theta)} \end{array}$ 8 end 9 end 10 $\theta_{\mathbf{n}}\gets \theta$ 11 $\mathbf{I}_{SR} = f(\mathbf{I}_{LR};\theta_{\mathbf{n}})$ 12 return $\mathbf{I}_{SR}$ + +![](images/5bb15bb37c5968ada6f539a3ee404aaac6b6a815ac83fa391f2542df17ada67f.jpg) +Figure 2: The network structure of MaskNet. + +The above process (as remarked by the circled numbers) describes the pipeline of MetaF2N during inference and the first six steps in the training phase. + +For training MetaF2N, we also need to calculate the outer loop loss $⑦$ , which is composed of fidelity loss $(\ell_1)$ , LPIPS loss [60], and GAN loss [13]. In specific, the fidelity loss is + +$$ +\mathcal {L} _ {1} = \left\| \mathbf {I} _ {S R} - \mathbf {I} \right\| _ {1}, \tag {8} +$$ + +and the LPIPS loss is defined by + +$$ +\mathcal {L} _ {\mathrm {L P I P S}} = \| \phi (\mathbf {I} _ {S R}) - \phi (\mathbf {I}) \| _ {2}, \tag {9} +$$ + +where $\phi$ is the pre-trained AlexNet [24] feature extractor for calculating LPIPS. The adversarial loss follows the setting of Real-ESRGAN [51], which is defined by, + +$$ +\mathcal {L} _ {\mathrm {a d v}} = - \mathbb {E} [ \log (D (\mathbf {I} _ {S R})) ], \tag {10} +$$ + +where the discriminator $D$ is iteratively trained along with the SR network, i.e., + +$$ +\mathcal {L} _ {D} = - \mathbb {E} [ \log (D (\mathbf {I})) - \log (1 - D (\mathbf {I} _ {S R})) ]. \tag {11} +$$ + +Note that some works [25,32] have explored training GANs under the meta-learning structure, and all of them update the discriminator loss in both the inner loop and outer loop. However, to accelerate the training process and save memory, we only update the discriminator loss in the outer loop, which also shows satisfactory results. + +To improve the numerical stability and avoid gradient exploding/vanishing, we constrain the MaskNet $f_{\mathbf{m}}$ via a regularization term, which is defined by + +$$ +\mathcal {L} _ {\text {r e g}} = \| \mathbf {m} - \mathbf {1} \| _ {2}. \tag {12} +$$ + +In summary, the learning objective of our MetaF2N (i.e., the outer loop loss) is + +$$ +\mathcal {L} ^ {T _ {\mathrm {i}}} = \lambda_ {1} \mathcal {L} _ {1} + \lambda_ {2} \mathcal {L} _ {\text {L P I I P S}} + \lambda_ {3} \mathcal {L} _ {\text {a d v}} + \lambda_ {4} \mathcal {L} _ {\text {r e g}}, \tag {13} +$$ + +where the hyperparameters $\lambda_1, \lambda_2, \lambda_3$ , and $\lambda_4$ are empirically set to 1, 0.5, 0.1, and 0.002, respectively. Please refer to Algorithms 1 and 2 for more details on the training and inference process of the proposed MetaF2N. + +# 5. Experiments + +# 5.1. Dataset and Training Details + +Training Data. For synthesizing data to train the proposed MetaF2N, high-quality facial and natural images are required for inner and outer loop, respectively. It is worth noting that, the requirement on the training data is that $\mathbf{I}_{LR}^{\odot}$ and $\mathbf{I}_{LR}$ share the identical degradation, but they are not necessarily from the same image. Therefore, to better leverage existing high-quality facial and natural image datasets, we use the first 30,000 images of the aligned FFHQ [21] dataset for the inner loop, and adopt DF2K1 with 3,450 images in total for the outer loop following recent blind image SR methods [26, 51, 59]. For a fair comparison against other methods, we follow the degradation setting of RealESRGAN [51] for low-quality image synthesis. More details are given in the supplementary material. + +Testing Data. To comprehensively evaluate the proposed MetaF2N, we have constructed several testing datasets. + +Synthetic datasets are built upon the in-the-wild version of FFHQ [21] and CelebA [34], where 1,000 high-quality images are extracted from each dataset, and faces occupy around $10\%$ areas of the whole image on average. With the high-quality images, we first construct two test datasets whose degradations are independent and identically distributed as the training set, which are denoted by $\mathrm{FFHQ}_{iid}$ and $\mathrm{CelebA}_{iid}$ , respectively. For evaluating the generalization ability on out-of-distribution degradations, we further construct $\mathrm{FFHQ}_{ood}$ and $\mathrm{CelebA}_{ood}$ by changing the parameters of the degradation model, e.g., Gaussian blur $\rightarrow$ motion blur, Gaussian/Poisson noise $\rightarrow$ Speckle noise. The detailed parameters are in the supplementary material. + +A real-world dataset RealFaces200 (RF200) is also established for evaluation under a real scenario, which contains 200 real-world low-quality images collected from the Internet or existing datasets (e.g., WIDER FACE [56]), and there are one or multiple faces in each image. + +Implementation Details. The proposed MetaF2N mainly focuses on leveraging meta-learning for efficient model adaptation for blind image SR, which is independent of network architecture and can be incorporated into arbitrary second-order differentiable models. Therefore, we follow Real-ESRGAN [51], BSRGAN [59], and ReDegNet [26] to adopt the architecture of ESRGAN [53]. For training, each image is cropped into patches, and the patch size is $128 \times 128$ for the inner loop (i.e., $\mathbf{I}_{LR}^{\ominus}$ , $\mathbf{I}_{BFR}^{\ominus}$ , and $\mathbf{I}_{SR}^{\ominus}$ ) and $256 \times 256$ for the outer loop (i.e., $\mathbf{I}_{LR}$ , $\mathbf{I}_{SR}$ , and $\mathbf{I}$ ). The Adam [23] optimizer with $\beta_{1} = 0.5$ and $\beta_{2} = 0.999$ is adopted. For the SR model $f$ , the learning rate (lr) of the inner and outer loops are $1 \times 10^{-2}$ and $3 \times 10^{-5}$ , respectively, while the lr for the discriminator and MaskNet are $1 \times 10^{-4}$ . + +The MetaF2N is trained for one week and all experiments are conducted on a server with one RTX A6000 GPU. + +# 5.2. Comparison with State-of-the-art Methods + +To show the effectiveness of the proposed MetaF2N, we compare with several state-of-the-art blind image SR methods, including ESRGAN [53], RealSR [5], Real-ESRGAN [51], BSRGAN [59], MM-RealSR [39], and RedegNet [26]. For quantitative evaluation, we utilize PSNR, LPIPS [60], FID [17], and NIQE [38] for synthetic datasets. As for the real-world dataset, since no ground-truth is available, PSNR and LPIPS are omitted. It is worth noting that KID is more accurate and appropriate than FID when evaluating the quality of images with a smaller amount of samples [3]. Thus we use KID [3] and NIQE [38] for quantitative evaluation on our RF200 dataset. To accurately calculate the distance between SR results and real-world high-quality images (i.e., FID and KID), we construct these types of reference images following [4], which estimates a blurriness score based on the total variance of the Laplacian of an image. Finally, 3,808 high-quality images are selected from the in-the-wild version of FFHQ [21], whose scores are higher than the threshold defined in [4]. + +Quantitative Comparison. The quantitative evaluation results are provided in Tabs. 1 and 2. We provide three results of our Meta-F2N, i.e., Ours (1), Ours (10), and Ours (20), where the number in the parentheses denotes the amount of fine-tuning steps during inference. All three models are initialized with the same parameter $\theta$ . For the degradations independent and identically distributed as the training set (i.e., $\mathrm{FFHQ}_{iid}$ and CelebA $_{iid}$ ), our MetaF2N can achieve superior performance on LPIPS, FID, and NIQE with only one fine-tuning step, and can surpass most of the competing methods on PSNR. Besides, with more fine-tuning iterations, the image quality can be further enhanced. For out-of-distribution degradations in Tab. 2 (i.e., $\mathrm{FFHQ}_{ood}$ , CelebA $_{ood}$ , and RF200), the trends are similar to Tab. 1, and our MetaF2N again outperforms others on most metrics, especially on the real-world RF200 dataset. + +As for the competing methods, ESRGAN [53] and RealSR [5] are trained with simple degradation models, which lead to unsatisfactory performance under more complex and realistic degradations. Real-ESRGAN [51], BSRGAN [59], MM-RealSR [39], and ReDegNet [26] leverage more realistic degradation models or even real-world degradations, which contribute to much better results, yet their performance is still limited by the deterministic model and fixed degradation range. Furthermore, we also fine-tune ReDegNet [26] on RF200, and the results are provided in Tab. 2 (ReDegNet†). Compared to MetaF2N that achieves decent performance with only one fine-tuning step, marginal improvements are observed on NIQE even the ReDegNet [26] is carefully fine-tuned hundreds iterations for each image. + +![](images/c8ca386e0de2c3584d6ca12fed7abdb22a5e99a53e26980e183ae0c122e96194.jpg) + +![](images/f3b31ca2fab7c3471e2a9ad48e47187e1b144eaf6b8d9b5199ff366af8034270.jpg) + +![](images/2d9e97d33919ac8efb54dd80671c9574c4c72b5cc9fcd71c9e60b90d6e94462a.jpg) +Synthetic LR + +![](images/2bd392cc1e47a22b82973331f50e847117f6f7a80c6735f067eb0c2f85f32df9.jpg) + +![](images/292ea930cf1604bdf0fbb5a971edaddfbfe9096750effb6c8f0544b5b90efa0a.jpg) + +![](images/f1e75c7d0e59e466e7ad140ea5e9c3dc788e8bee02cc885edcc2bfe7d899b600.jpg) +Real-ESRGAN [51] + +![](images/0c02920714760cde53e52f10961386449a98e208622d08bbf1513c083b2c004b.jpg) + +![](images/e6dc186542afe93de71dde448aaf69b1f4a80ac63a53d1c8d99129103cc58321.jpg) + +![](images/99ba1bdcef4e921812ba41bf73752c5273244211158136940ff7f510c311c448.jpg) +BSRGAN [59] + +![](images/74d460472d7bf866569be3e53cab3a9c43d14e7e16d1446fb38ea6db3b49df9b.jpg) + +![](images/70d3b07a36f62d2f31f99596c686658cb43f2da55da5e52747478d34651b4455.jpg) + +![](images/0541b81921d249d49026ccb8080bf4198eff49a84b67bbe5b0df49f787e425bb.jpg) +MM-RealSR [39] + +![](images/abb288e6bda4880caa82cb1774933f7082f0ce575766f9cb6052c58a9341392b.jpg) + +![](images/15021f1bf6a6c95c7c2ac93c12ad1d3e6ea94924f5267e257a8cd93575a30536.jpg) + +![](images/b837f5e322ecc33faf7ea74ef87fe4522141f97100dac29b949ba2d8aa67fccc.jpg) +ReDegNet [26] + +![](images/29b72e2f104a64ee8702acb7911cac1c4452e02489f014291fd7ae704c5a9bed.jpg) + +![](images/dc81b3f8f3c8b473713d69035fb81c6be0939d527a069e6d7240ad5819e3c1dd.jpg) + +![](images/984046f723fff7f99e07838ed578a16058eadb2afdc9f7e5d5008264bba39709.jpg) +Ours + +![](images/f21d224c7d56e794af53dceb6ee7449430fb802b184c84631c58b11260d4ebe7.jpg) + +![](images/33eade57d93a7503b3bf9362dea39b9b4699c7fdcdece28ff0fc98cdb59485c7.jpg) + +![](images/db61604dff7829b6f647b07f718ba3be647a77fdc95ec20440157f1ba39e1a60.jpg) +Ground-truth + +![](images/90797db8f37ca3f626263e3467c025a3b6daf24d4c7027243aa172e4a34ee365.jpg) +Figure 3: Visual comparison against state-of-the-art blind SR methods on synthetic datasets. Note that the results of Ours are produced by MetaF2N with one-step fine-tuning. Please zoom in for better observation. + +![](images/8477c94867bccef0f2e092a06bc95edd49225d2567fd0b119ad2d5488eda1b83.jpg) + +![](images/a3a12e5762cf3f501334faf7e58216bcbe1e5fba9bbe0a5e742b6cd231caab11.jpg) +Real-world LR +Figure 4: Visual comparison against state-of-the-art blind SR methods on real-world low-quality images in our RF200 dataset. ReDegNet† means that model is fine-tuned for each image following the official configurations of ReDegNet [26]. + +![](images/d8ae5eb836c1a586985c8c205d978e5dd1dcc76b382a24c62ca6b99aecf71bc8.jpg) + +![](images/c22bcdd62f1d5e267cdac7e4b9830f84f84c8318399d8da4075fb88eff8d7bb9.jpg) + +![](images/1091e6238610d5240f91ff921d3aac814380fef45bb2463a90568c9b5ff0c93e.jpg) +Real-ESRGAN [51] + +![](images/29917520a90e722128280dfb2f62f71a86570122f15fbb7f5d80399b9bb91edc.jpg) + +![](images/f090cb66ca59e509a787d5b78ea8e38d6b8c8345091309f1735ccb4d5e8714d5.jpg) + +![](images/bd396fc02925daaa1bf24073e85323d895aa360e1a3204094127a9eecbf93f6a.jpg) +BSRGAN [59] + +![](images/48a60a266aa0fb4ec000bb1d0b7380d1fa2aa70779e06f8e87762b7dab5bb45a.jpg) + +![](images/1fec9269dc52275437abfd001bcace5e3a5142b5673311195a67d3bd11dbd92f.jpg) + +![](images/dc200565769a18bb3bc6c3436f274ae9a4c3fbdaddd46d6c1929258f9d164c20.jpg) +MM-RealSR [39] + +![](images/a1a4554caed9fb7c9177b1eb295a29a852856fb04428acf3723be79ba89ae773.jpg) + +![](images/68e8ab179dfa3fe19d8c7a877a2652150cc019b89928efaf5cce42433e3302d2.jpg) + +![](images/b9eafe7835425c64b34aa7655334e57538466b56badae1db2ca7b8eeefb50a45.jpg) +ReDegNet [26] + +![](images/8fe645a0101fc0c3cb776d937913870ab102bb3052df6f9d34f9b79f8bb53f6c.jpg) + +![](images/a6f9d6da8d1977ee9caf0f43ffa941159927cbb3933052f7ba235d6382d52ee0.jpg) + +![](images/67566032ef532b513c75c788940df48b7da70161d2283de9677eb48ec3f6bf3d.jpg) +ReDegNet [26] + +![](images/08faeaf42b6832cd8a3a0e2783482caadddb568d696121cb1d342d7f0f86551d.jpg) + +![](images/1d0872bcbeb1cd4a6bdfcc69f175d8f45376aee4121df3f9304f864d0419c765.jpg) + +![](images/3709756ab95397b548fd4a3ec2724dca4b10000d6a5322fda6e7d223126e26ab.jpg) +Ours + +Qualitative Comparison. Apart from the quantitative comparison, we also compare our MetaF2N with state-of-the-art blind image SR methods qualitatively. Due to the space limit, we show the results generated by Ours (1), which is fine-tuned for 1 step with the face regions, and more qualitative results (including those generated by Ours (10) and Ours (20)) are provided in the supplementary material. As shown in Figs. 3 and 4, our results are much clearer and contain more photo-realistic textures, which can be ascribed to the effectiveness of our image-specific fine-tuning scheme. + +# 5.3. The Visual Results of MaskNet + +To better explain the effect of our MaskNet, we calculate the error map $EM$ between ground-truth faces $\mathbf{I}^{\odot}$ and + +GPEN [57] generated faces $\mathbf{I}_{BFR}^{\odot}$ directly through subtraction and normalization, i.e., + +$$ +E M = \frac {\left| \mathbf {I} ^ {\ominus} - \mathbf {I} _ {B F R} ^ {\ominus} \right|}{\operatorname* {m a x} \left(\left| \mathbf {I} ^ {\ominus} - \mathbf {I} _ {B F R} ^ {\ominus} \right|\right)}. \tag {14} +$$ + +In Fig. 5, we show the predicted $\mathbf{m}$ and $1 - EM$ . One can see that the predicted $\mathbf{m}$ follows similar distribution to $1 - EM$ , indicating that our MaskNet has the ability to predict the gap between generated faces and real ones, which benefits the blind image SR performance. Besides, the predicted $\mathbf{m}$ is smoother than $1 - EM$ , due to that 1) $\mathbf{m}$ is predicted from $(\mathbf{I}_{LR}^{\ominus}$ and $\mathbf{I}_{BFR}^{\ominus})$ , which lead to less accurate results, and 2) a regularization term $\mathcal{L}_{\mathrm{reg}} = \| \mathbf{m} - 1\|_2$ is applied to constrain $\mathbf{m}$ not to deviate too far from 1. + +Table 1: Quantitative comparison on synthetic datasets with independent and identically distributed degradations as the training set. We also show the datasets used for training each method. Note that RealFaces used by ReDegNet [26] consists of 10,000 real-world low-quality face images collected by the authors. The numbers in the parentheses are the image-specific fine-tuning steps of our MetaF2N during inference. The best and second-best results are highlighted by bold and underline. + +
MethodsTraining SetFFHQiiidCelebAiid
PSNR↑LPIPS↓FID↓NIQE↓PSNR↑LPIPS↓FID↓NIQE↓
ESRGAN [53]DF2K [1,46], OST [52]25.100.642123.677.5624.780.55599.106.27
RealSR [19]DF2K [1,46]25.390.597122.237.5924.740.54999.465.77
Real-ESRGAN [51]DF2K [1,46], OST [52]26.350.29350.704.8525.810.31151.695.00
BSRGAN [59]DF2K [1,46], FFFHQ [21], WED [35]26.270.30550.984.6325.860.30950.054.83
MM-RealSR [39]DF2K [1,46], OST [52]25.390.29550.834.5824.940.31152.304.76
ReDegNet [26]DF2K [1,46], FFFHQ [21], RealFaces25.640.30957.044.7925.170.32956.844.94
Ours (1)DF2K [1,46], FFFHQ [21]26.130.28144.943.8125.630.28945.723.97
Ours (10)DF2K [1,46], FFFHQ [21]26.220.28044.943.8725.700.28945.434.03
Ours (20)DF2K [1,46], FFFHQ [21]26.300.27944.513.9425.760.28945.224.10
+ +Table 2: Quantitative comparison on synthetic datasets with out-of-distribution degradations and the collected real-world dataset RF200. ReDegNet† means that model is fine-tuned for each image following the official configurations of ReDeg-Net [26]. The numbers in the parentheses are the image-specific fine-tuning steps of our MetaF2N during inference. The best and second-best results are highlighted by bold and underline. + +
MethodsFFHQoodCelebAoodRF200
PSNR↑LPIPS↓FID↓NIQE↓PSNR↑LPIPS↓FID↓NIQE↓KID↓NIQE↓
ESRGAN [53]24.690.659101.436.9424.070.56787.615.6421.85.32
RealSR [19]24.910.58797.426.3323.980.56790.305.5121.95.00
Real-ESRGAN [51]25.730.30247.875.3425.070.32248.775.4322.43.82
BSRGAN [59]25.730.29846.404.7825.330.31348.124.9122.14.11
MM-RealSR [39]25.030.29747.304.9924.410.31748.765.1022.14.12
ReDegNet [26]25.540.30448.475.0924.760.33152.335.2823.54.07
ReDegNet†[26]--------23.83.56
Ours (1)25.490.28445.074.2224.870.29747.034.3221.23.03
Ours (10)25.570.28444.644.3024.930.29746.504.3921.03.08
Ours (20)25.650.28344.304.3625.000.29746.234.4720.83.12
+ +# 5.4. Ablation Studies + +To verify the effectiveness of the components of the proposed MetaF2N, we have also conducted several ablation studies. Without loss of generality, all ablation studies are performed with $\mathrm{FFHQ}_{i id}$ based on Ours (1). Due to the space limit, qualitative results of ablation studies are given in the supplementary material. + +MaskNet Configuration. To show the effectiveness of the MaskNet, we train a variant of our MetaF2N by removing the MaskNet. Besides, as introduced in Sec. 1, we design the MaskNet inspired by degraded-reference IQA methods, which takes both low-quality and restored faces as input (denoted by $\mathrm{MaskNet}_{DR}$ ). For verifying the design, we also consider another variant of MetaF2N which utilizes the non-reference scheme, i.e., only the restored face is taken by the MaskNet (denoted by $\mathrm{MaskNet}_{NR}$ ). As shown in Tab. 3, the deployment of MaskNet brings considerable improvements, and utilizing the low-quality face image as a reference is also useful for our task. + +Training Data Configuration. Since ground-truth faces are available during training, we train another variant by using the ground-truth face image as the inner loop supervision. Note that the MaskNet is trained together with the SR model, and we omitted it when training the version using ground-truth faces as inner loop supervision since the optimal solution should be an all-one mask. As shown in Tab. 3, the performance decreases by a large margin compared to MetaF2N, which is attributed to the gaps in the inner loop supervision between the training and inference phases. + +Inner Loop Supervision Scheme. Since there are often multiple faces in a single image, as a natural extension of our method, it is intuitive to apply multiple faces to stabilize the fine-tuning process. Therefore, we also explore the inner loop supervision scheme based on another 1,000 images sampled from the in-the-wild version of FFHQ [21] with multiple faces. As shown in Tab. 4, using patches of multiple faces can slightly benefit the final performance. + +Influence of Different Face Hallucination Network. To + +![](images/5547abbf98f572c9575eed8c353976212af4198d644908cbd849dcf27353b6cb.jpg) +Figure 5: Visual results of MaskNet. + +find the influence of different face hallucination network for the MetaF2N, we conduct an ablation study by replacing GPEN [57] with CodeFormer [63] during training and testing. As shown in Tab. 5, one can see that our MetaF2N shows satisfactory robustness with different face hallucination networks for both $\mathrm{FFHQ}_{i\bar{i}d}$ and $\mathrm{FFHQ}_{\mathrm{ood}}$ . Although the CodeFormer [63] can restore higher quality faces compared with GPEN [57], our MaskNet minish the gap through allocating weights for each pixel of restored faces, which enhances the robustness of MetaF2N for different face hallucination networks. + +Table 3: Ablation study on the training scheme regarding data configuration and the MaskNet. Train/Test Faces denote the setting of inner-loop supervision during the training and inference stages. + +
MaskNetTrain FacesTest FacesPSNR↑LPIPS↓FID↓NIQE↓
-GTGPEN25.680.28546.964.08
-GPENGPEN26.170.28447.894.21
MaskNetNRGPENGPEN26.070.28447.974.09
MaskNetDRGPENGPEN26.130.28145.223.81
+ +Table 4: Ablation study on inner loop supervision, which is performed on 1,000 images with multiple faces ( $\sim$ 2.3 faces/image) from the in-the-wild version of FFHQ [21]. + +
# of FacesData FormPSNR↑LPIPS↓FID↓NIQE↓
SingleFull image25.730.28842.963.63
Single32 patches25.770.28842.893.65
Multiple32 patches in total25.790.28742.853.65
Multiple32 patches per face25.790.28742.813.65
+ +Table 5: Ablation study on face hallucination networks which is performed on both $\mathrm{FFHQ}_{iid}$ and $\mathrm{FFHQ}_{ood}$ . + +
TestsetsTrain FacesTest FacesPSNR↑LPIPS↓FID↓NIQE↓
FFHQidGPENGPEN26.130.28145.223.81
CodeFormerCodeFormer26.100.27845.833.83
FFHQoodGPENGPEN25.490.28445.074.22
CodeFormerCodeFormer25.510.28144.584.24
+ +# 5.5. Limitations and Future Work + +Since our MetaF2N is trained in a MAML framework, the performance before fine-tuning is unconstrained. As such, our model requires fine-tuning with the contained faces for one or multiple steps, making it cannot be directly applied if no faces exist in real-world low-quality images, which limits the application scenarios of our method. In the future, we plan to solve this problem by collecting a real-world low-quality training set and providing a better initialization of parameters that can be used to achieve satisfactory performance even without fine-tuning. + +# 6. Conclusion + +In this paper, we proposed a MetaF2N framework for face-guided blind image SR. The MetaF2N improves the practicability of leveraging blind face restoration for processing image-specific degradations. A MaskNet is deployed to predict the loss weights for different positions considering the gaps between recovered faces and potential ground-truth ones. The proposed MetaF2N achieves superior performance on synthetic datasets with both independent and identically distributed and out-of-distribution degradations compared to training sets. The effectiveness is also validated on the collected real-world dataset. + +# Acknowledgement + +This work was supported in part by the National Key Research and Development Program of China under Grant No. 2022YFA1004103 and the National Natural Science Foundation of China (NSFC) under Grant No. U19A2073. + +# References + +[1] Eirikur Agustsson and Radu Timofte. NTIRE 2017 challenge on single image super-resolution: Dataset and study. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 126-135, 2017. 6, 8 +[2] Shahrukh Athar and Zhou Wang. Degraded reference image quality assessment. IEEE Transactions on Image Processing, pages 822-837, 2023. 2, 4 +[3] Mikołaj Binkowski, Danica J Sutherland, Michael Arbel, and Arthur Gretton. Demystifying mmd gans. In International Conference on Learning Representations, pages 1-36, 2018. 6 +[4] Will Brennan. BlurDetection2. https://github.com/WillBrennan/BlurDetection2, 2017.6 +[5] Jianrui Cai, Hui Zeng, Hongwei Yong, Zisheng Cao, and Lei Zhang. Toward real-world single image super-resolution: A new benchmark and a new model. In IEEE International Conference on Computer Vision, pages 3086-3095, 2019. 1, 2, 6 +[6] Kelvin CK Chan, Xintao Wang, Xiangyu Xu, Jinwei Gu, and Chen Change Loy. GLEAN: Generative latent bank for large-factor image super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 14245-14254, 2021. 3, 4 +[7] Chaofeng Chen, Xiaoming Li, Lingbo Yang, Xianhui Lin, Lei Zhang, and Kwan-Yee K Wong. Progressive semantic-aware style transformation for blind face restoration. In IEEE Conference on Computer Vision and Pattern Recognition, pages 11896-11905, 2021. 3 +[8] Chang Chen, Zhiwei Xiong, Xinmei Tian, Zheng-Jun Zha, and Feng Wu. Camera lens super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 1652-1660, 2019. 1, 2 +[9] Honggang Chen, Xiaohai He, Linbo Qing, Yuanyuan Wu, Chao Ren, Ray E Sheriff, and Ce Zhu. Real-world single image super-resolution: A brief review. Information Fusion, pages 124-145, 2022. 1, 2 +[10] Mohammad Emad, Maurice Peemen, and Henk Corporaal. DualSR: Zero-shot dual learning for real-world superresolution. In IEEE Winter Conference on Applications of Computer Vision, pages 1630-1639, 2021. 1 +[11] Chelsea Finn, Pieter Abbeel, and Sergey Levine. Model-agnostic meta-learning for fast adaptation of deep networks. In International Conference on Machine Learning, pages 1126–1135, 2017. 2, 3 +[12] Manuel Fritsche, Shuhang Gu, and Radu Timofte. Frequency separation for real-world super-resolution. In IEEE International Conference on Computer Vision Workshops, pages 3599-3608, 2019. 2 +[13] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. Communications of the ACM, pages 139–144, 2020. 5 +[14] Erin Grant, Chelsea Finn, Sergey Levine, Trevor Darrell, and Thomas Griffiths. Recasting gradient-based meta-learning as hierarchical bayes. arXiv preprint arXiv:1801.08930, 2018. 3 + +[15] Jinjin Gu, Hannan Lu, Wangmeng Zuo, and Chao Dong. Blind super-resolution with iterative kernel correction. In IEEE Conference on Computer Vision and Pattern Recognition, pages 1604-1613, 2019. 2 +[16] Yuchao Gu, Xintao Wang, Liangbin Xie, Chao Dong, Gen Li, Ying Shan, and Ming-Ming Cheng. VQFR: Blind face restoration with vector-quantized dictionary and parallel decoder. In European Conference on Computer Vision, pages 126–143, 2022. 3 +[17] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in Neural Information Processing Systems, pages 6626-6637, 2017. 6 +[18] Yan Huang, Shang Li, Liang Wang, Tieniu Tan, et al. Unfolding the alternating optimization for blind super resolution. Advances in Neural Information Processing Systems, pages 5632-5643, 2020. 2 +[19] Xiaozhong Ji, Yun Cao, Ying Tai, Chengjie Wang, Jilin Li, and Feiyue Huang. Real-world super-resolution via kernel estimation and noise injection. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 466-467, 2020. 2, 8 +[20] Hamid Reza Vaezi Joze, Ilya Zharkov, Karlton Powell, Carl Ringler, Luming Liang, Andy Roulston, Moshe Lutz, and Vivek Pradeep. ImagePairs: Realistic super resolution dataset via beam splitter camera rig. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 518-519, 2020. 2 +[21] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In IEEE Conference on Computer Vision and Pattern Recognition, pages 4401-4410, 2019. 2, 6, 8, 9 +[22] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of stylegan. In IEEE Conference on Computer Vision and Pattern Recognition, pages 8110-8119, 2020. 3 +[23] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. 6 +[24] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E Hinton. Imagenet classification with deep convolutional neural networks. Communications of the ACM, pages 84-90, 2017. 5 +[25] Royson Lee, Rui Li, Stylianos I Venieris, Timothy Hospedales, Ferenc Huszár, and Nicholas D Lane. Metalearned kernel for blind super-resolution kernel estimation. arXiv preprint arXiv:2212.07886, 2022. 3, 5 +[26] Xiaoming Li, Chaofeng Chen, Xianhui Lin, Wangmeng Zuo, and Lei Zhang. From face to natural image: Learning real degradation for blind image super-resolution. In European Conference on Computer Vision, pages 376-392, 2022. 1, 3, 4, 6, 7, 8 +[27] Xiaoming Li, Chaofeng Chen, Shangchen Zhou, Xianhui Lin, Wangmeng Zuo, and Lei Zhang. Blind face restoration via deep multi-scale component dictionaries. In European Conference on Computer Vision, pages 399-415, 2020. 3 + +[28] Xiaoming Li, Wenyu Li, Dongwei Ren, Hongzhi Zhang, Meng Wang, and Wangmeng Zuo. Enhanced blind face restoration with multi-exemplar images and adaptive spatial feature fusion. In IEEE Conference on Computer Vision and Pattern Recognition, pages 2706-2715, 2020. 3 +[29] Xiaoming Li, Ming Liu, Yuting Ye, Wangmeng Zuo, Liang Lin, and Ruigang Yang. Learning warped guidance for blind face restoration. In European Conference on Computer Vision, pages 272-289, 2018. 3 +[30] Xiaoming Li, Shiguang Zhang, Shangchen Zhou, Lei Zhang, and Wangmeng Zuo. Learning dual memory dictionaries for blind face restoration. IEEE Transactions on Pattern Analysis and Machine Intelligence, pages 1-13, 2022. 3 +[31] Xiaoming Li, Wangmeng Zuo, and Chen Change Loy. Learning generative structure prior for blind text image super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 10103-10113, 2023. 3 +[32] Weixin Liang, Zixuan Liu, and Can Liu. Dawson: A domain adaptive few shot generation framework. arXiv preprint arXiv:2001.00576, 2020. 5 +[33] Anran Liu, Yihao Liu, Jinjin Gu, Yu Qiao, and Chao Dong. Blind image super-resolution: A survey and beyond. IEEE Transactions on Pattern Analysis and Machine Intelligence, pages 1-19, 2022. 1, 2 +[34] Ziwei Liu, Ping Luo, Xiaogang Wang, and Xiaou Tang. Deep learning face attributes in the wild. In IEEE International Conference on Computer Vision, pages 3730-3738, 2015. 2, 6 +[35] Kede Ma, Zhengfang Duanmu, Qingbo Wu, Zhou Wang, Hongwei Yong, Hongliang Li, and Lei Zhang. Waterloo exploration database: New challenges for image quality assessment models. IEEE Transactions on Image Processing, pages 1004-1016, 2016. 8 +[36] Sachit Menon, Alexandru Damian, Shijia Hu, Nikhil Ravi, and Cynthia Rudin. PULSE: Self-supervised photo upsampling via latent space exploration of generative models. In IEEE Conference on Computer Vision and Pattern Recognition, pages 2437-2445, 2020. 1 +[37] Nikhil Mishra, Mostafa Rohaninejad, Xi Chen, and Pieter Abbeel. A simple neural attentive meta-learner. arXiv preprint arXiv:1707.03141, 2017. 3 +[38] Anish Mittal, Rajiv Soundararajan, and Alan C Bovik. Making a "completely blind" image quality analyzer. IEEE Signal Processing Letters, pages 209-212, 2012. 6 +[39] Chong Mou, Yanze Wu, Xintao Wang, Chao Dong, Jian Zhang, and Ying Shan. Metric learning based interactive modulation for real-world super-resolution. In European Conference on Computer Vision, pages 723-740, 2022. 6, 7, 8 +[40] Boris Oreshkin, Pau Rodríguez López, and Alexandre Lacoste. TADAM: Task dependent adaptive metric for improved few-shot learning. Advances in Neural Information Processing Systems, pages 719-729, 2018. 3 +[41] Seobin Park, Jinsu Yoo, Donghyeon Cho, Jiwon Kim, and Tae Hyun Kim. Fast adaptation to super-resolution networks via meta-learning. In European Conference on Computer Vision, pages 754-769, 2020. 3, 4 + +[42] Assaf Shocher, Nadav Cohen, and Michal Irani. "zero-shot" super-resolution using deep internal learning. In IEEE Conference on Computer Vision and Pattern Recognition, pages 3118-3126, 2018. 1, 2 +[43] Jae Woong Soh, Sunwoo Cho, and Nam Ik Cho. Meta-transfer learning for zero-shot super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 3516-3525, 2020. 3, 4 +[44] Qianru Sun, Yaoyao Liu, Tat-Seng Chua, and Bernt Schiele. Meta-transfer learning for few-shot learning. In IEEE Conference on Computer Vision and Pattern Recognition, pages 403-412, 2019. 3 +[45] Flood Sung, Yongxin Yang, Li Zhang, Tao Xiang, Philip HS Torr, and Timothy M Hospedales. Learning to compare: Relation network for few-shot learning. In IEEE Conference on Computer Vision and Pattern Recognition, pages 1199-1208, 2018. 3 +[46] Radu Timofte, Eirikur Agustsson, Luc Van Gool, Ming-Hsuan Yang, and Lei Zhang. NTIRE 2017 challenge on single image super-resolution: Methods and results. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 114-125, 2017. 6, 8 +[47] Dmitry Ulyanov, Andrea Vedaldi, and Victor Lempitsky. Deep image prior. In IEEE Conference on Computer Vision and Pattern Recognition, pages 9446-9454, 2018. 1, 2 +[48] Oriol Vinyals, Charles Blundell, Timothy Lillicrap, Daan Wierstra, et al. Matching networks for one shot learning. Advances in Neural Information Processing Systems, pages 3630-3638, 2016. 3 +[49] Longguang Wang, Yingqian Wang, Xiaoyu Dong, Qingyu Xu, Jungang Yang, Wei An, and Yulan Guo. Unsupervised degradation representation learning for blind superresolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 10581-10590, 2021. 2 +[50] Xintao Wang, Yu Li, Honglun Zhang, and Ying Shan. Towards real-world blind face restoration with generative facial prior. In IEEE Conference on Computer Vision and Pattern Recognition, pages 9168-9178, 2021. 1, 3, 4 +[51] Xintao Wang, Liangbin Xie, Chao Dong, and Ying Shan. Real-ESRGAN: Training real-world blind super-resolution with pure synthetic data. In IEEE International Conference on Computer Vision, pages 1905–1914, 2021. 1, 2, 5, 6, 7, 8 +[52] Xintao Wang, Ke Yu, Chao Dong, and Chen Change Loy. Recovering realistic texture in image super-resolution by deep spatial feature transform. In IEEE Conference on Computer Vision and Pattern Recognition, pages 606-615, 2018. 8 +[53] Xintao Wang, Ke Yu, Shixiang Wu, Jinjin Gu, Yihao Liu, Chao Dong, Yu Qiao, and Chen Change Loy. ESRGAN: Enhanced super-resolution generative adversarial networks. In European Conference on Computer Vision Workshops, pages 63-79, 2018. 2, 4, 6, 8 +[54] Zhouxia Wang, Jiawei Zhang, Runjian Chen, Wenping Wang, and Ping Luo. RestoreFormer: High-quality blind face restoration from undegraded key-value pairs. In IEEE Conference on Computer Vision and Pattern Recognition, pages 17491-17500, 2022. 3 + +[55] Pengxu Wei, Ziwei Xie, Hannan Lu, Zongyuan Zhan, Qixiang Ye, Wangmeng Zuo, and Liang Lin. Component divide-and-conquer for real-world image super-resolution. In European Conference on Computer Vision, pages 101-117, 2020. 1, 2 +[56] Shuo Yang, Ping Luo, Chen Change Loy, and Xiaou Tang. Wider face: A face detection benchmark. In IEEE Conference on Computer Vision and Pattern Recognition, pages 5525-5533, 2016. 6 +[57] Tao Yang, Peiran Ren, Xuansong Xie, and Lei Zhang. Gan prior embedded network for blind face restoration in the wild. In IEEE Conference on Computer Vision and Pattern Recognition, pages 672-681, 2021. 1, 3, 4, 5, 7, 9 +[58] Yuan Yuan, Siyuan Liu, Jiawei Zhang, Yongbing Zhang, Chao Dong, and Liang Lin. Unsupervised image superresolution using cycle-in-cycle generative adversarial networks. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 701-710, 2018. 2 +[59] Kai Zhang, Jingyun Liang, Luc Van Gool, and Radu Timofte. Designing a practical degradation model for deep blind image super-resolution. In IEEE International Conference on Computer Vision, pages 4791-4800, 2021. 1, 2, 6, 7, 8 +[60] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In IEEE Conference on Computer Vision and Pattern Recognition, pages 586-595, 2018. 5, 6 +[61] Xuaner Zhang, Qifeng Chen, Ren Ng, and Vladlen Koltun. Zoom to learn, learn to zoom. In IEEE Conference on Computer Vision and Pattern Recognition, pages 3762-3770, 2019. 1 +[62] Heliang Zheng, Huan Yang, Jianlong Fu, Zheng-Jun Zha, and Jiebo Luo. Learning conditional knowledge distillation for degraded-reference image quality assessment. In IEEE International Conference on Computer Vision, pages 10242-10251, 2021. 2, 4 +[63] Shangchen Zhou, Kelvin CK Chan, Chongyi Li, and Chen Change Loy. Towards robust blind face restoration with codebook lookup transformer. arXiv preprint arXiv:2206.11253, 2022. 1, 3, 9 +[64] Feida Zhu, Junwei Zhu, Wenqing Chu, Xinyi Zhang, Xiaozhong Ji, Chengjie Wang, and Ying Tai. Blind face restoration via integrating face shape and generative priors. In IEEE Conference on Computer Vision and Pattern Recognition, pages 7662-7671, 2022. 3, 4 \ No newline at end of file diff --git a/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/images.zip b/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..868b734e81edf5e2bc56fc458305008def122a22 --- /dev/null +++ b/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:dfaa43e24a2df7fe299658758f08816e0d635140f9ad23f87f062095375b66f7 +size 733987 diff --git a/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/layout.json b/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..cfb6d8683ebd941e592ab0013d5f7749e241f90c --- /dev/null +++ b/2023/MetaF2N_ Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces/layout.json @@ -0,0 +1,13182 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 151, + 153, + 426, + 186 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 151, + 153, + 426, + 186 + ], + "spans": [ + { + "bbox": [ + 151, + 153, + 426, + 186 + ], + "type": "text", + "content": "MetaF2N: Blind Image Super-Resolution by Learning Efficient Model Adaptation from Faces" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 155, + 212, + 419, + 226 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 155, + 212, + 419, + 226 + ], + "spans": [ + { + "bbox": [ + 155, + 212, + 419, + 226 + ], + "type": "text", + "content": "Zhicun Yin" + }, + { + "bbox": [ + 155, + 212, + 419, + 226 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 155, + 212, + 419, + 226 + ], + "type": "text", + "content": " Ming Liu" + }, + { + "bbox": [ + 155, + 212, + 419, + 226 + ], + "type": "inline_equation", + "content": "^{1(\\boxtimes)}" + }, + { + "bbox": [ + 155, + 212, + 419, + 226 + ], + "type": "text", + "content": " Xiaoming Li" + }, + { + "bbox": [ + 155, + 212, + 419, + 226 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 155, + 212, + 419, + 226 + ], + "type": "text", + "content": " Hui Yang" + }, + { + "bbox": [ + 155, + 212, + 419, + 226 + ], + "type": "inline_equation", + "content": "^{2}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 210, + 226, + 367, + 239 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 210, + 226, + 367, + 239 + ], + "spans": [ + { + "bbox": [ + 210, + 226, + 367, + 239 + ], + "type": "text", + "content": "Longan Xiao2 Wangmeng Zuo1,3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 84, + 239, + 495, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 84, + 239, + 495, + 251 + ], + "spans": [ + { + "bbox": [ + 84, + 239, + 495, + 251 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 84, + 239, + 495, + 251 + ], + "type": "text", + "content": " Harbin Institute of Technology " + }, + { + "bbox": [ + 84, + 239, + 495, + 251 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 84, + 239, + 495, + 251 + ], + "type": "text", + "content": " Shanghai Transsion Co, Ltd " + }, + { + "bbox": [ + 84, + 239, + 495, + 251 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 84, + 239, + 495, + 251 + ], + "type": "text", + "content": " Peng Cheng Laboratory" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 104, + 254, + 474, + 263 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 104, + 254, + 474, + 263 + ], + "spans": [ + { + "bbox": [ + 104, + 254, + 474, + 263 + ], + "type": "text", + "content": "cszcyin@outlook.com, csmliu@outlook.com, csxml@gmail.com, wmzuo@hit.edu.cn" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 149, + 289, + 192, + 300 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 149, + 289, + 192, + 300 + ], + "spans": [ + { + "bbox": [ + 149, + 289, + 192, + 300 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 60, + 312, + 282, + 618 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 312, + 282, + 618 + ], + "spans": [ + { + "bbox": [ + 60, + 312, + 282, + 618 + ], + "type": "text", + "content": "Due to their highly structured characteristics, faces are easier to recover than natural scenes for blind image super-resolution. Therefore, we can extract the degradation representation of an image from the low-quality and recovered face pairs. Using the degradation representation, realistic low-quality images can then be synthesized to fine-tune the super-resolution model for the real-world low-quality image. However, such a procedure is time-consuming and laborious, and the gaps between recovered faces and the ground-truths further increase the optimization uncertainty. To facilitate efficient model adaptation towards image-specific degradations, we propose a method dubbed MetaF2N, which leverages the contained Faces to fine-tune model parameters for adapting to the whole Natural image in a Meta-learning framework. The degradation extraction and low-quality image synthesis steps are thus circumvented in our MetaF2N, and it requires only one fine-tuning step to get decent performance. Considering the gaps between the recovered faces and groundtruths, we further deploy a MaskNet for adaptively predicting loss weights at different positions to reduce the impact of low-confidence areas. To evaluate our proposed MetaF2N, we have collected a real-world low-quality dataset with one or multiple faces in each image, and our MetaF2N achieves superior performance on both synthetic and real-world datasets. Source code, pre-trained models, and collected datasets are available at https://github.com/yinzhicun/MetaF2N." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 61, + 637, + 134, + 649 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 637, + 134, + 649 + ], + "spans": [ + { + "bbox": [ + 61, + 637, + 134, + 649 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 60, + 655, + 280, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 655, + 280, + 711 + ], + "spans": [ + { + "bbox": [ + 60, + 655, + 280, + 711 + ], + "type": "text", + "content": "With the development of dataset construction, network design, and many other relevant methods, blind image super-resolution (SR) [9, 33] has acquired enormous progress in recent years. To construct pairwise low-/high-quality samples for training the image SR models, typically" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 290, + 517, + 389 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 290, + 517, + 389 + ], + "spans": [ + { + "bbox": [ + 296, + 290, + 517, + 389 + ], + "type": "text", + "content": "one can capture low- and high-quality pairs by adjusting the focal length of cameras [5, 55, 61] and shooting distance [8], or synthesize low-quality images via degradation modeling [26, 51, 59]. However, these methods can only cover a limited and biased range of degradations, which is insufficient for real-world applications. Besides, most existing blind image SR methods [51, 59] train a static model for all testing scenarios, greatly limiting their flexibility and generalization ability." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 296, + 391, + 517, + 600 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 391, + 517, + 600 + ], + "spans": [ + { + "bbox": [ + 296, + 391, + 517, + 600 + ], + "type": "text", + "content": "In order to break the restriction of limited training sets, self-supervised learning has been introduced to train a model for each low-quality image, without requiring pairwise ground-truths [10, 42, 47]. Although these methods exhibit a great deal of flexibility, they largely rely on certain priors or assumptions, showing inferior image SR performance. Recently, Li et al. [26] reached a better compromise on the requirement of ground-truths and proposed ReDegNet by leveraging the faces contained in natural images. In specific, the face regions in a real-world low-quality natural image are processed via blind face SR methods [36, 50, 57, 63], which have achieved appealing results thanks to the highly structured characteristics of faces. Then, the low-quality and recovered face pairs can be utilized to model the degradations in the image. Finally, more low-quality images are synthesized with the degradation representations for fine-tuning the SR model. With the above design, ReDegNet [26] is flexible to process a single image or a batch of images with diverse degradations." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 601, + 517, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 601, + 517, + 712 + ], + "spans": [ + { + "bbox": [ + 296, + 601, + 517, + 712 + ], + "type": "text", + "content": "Although ReDegNet [26] achieves superior SR performance, especially in specific scenarios (i.e., fine-tuning with faces within the test image), there are still several limitations. On the one hand, the training procedure is time-consuming and computationally intensive, where the modules for degradation representation extraction and low-quality image synthesis are jointly optimized. Furthermore, when the model is intended to deal with a single low-quality image, it is difficult to determine when to terminate the training process for avoiding under-fitting or over-fitting." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 57, + 7, + 101, + 39 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 57, + 7, + 101, + 39 + ], + "spans": [ + { + "bbox": [ + 57, + 7, + 101, + 39 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 138, + 6, + 485, + 41 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 138, + 6, + 485, + 41 + ], + "spans": [ + { + "bbox": [ + 138, + 6, + 485, + 41 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "spans": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "type": "text", + "content": "13033" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 60, + 125, + 280, + 212 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 125, + 280, + 212 + ], + "spans": [ + { + "bbox": [ + 60, + 125, + 280, + 212 + ], + "type": "text", + "content": "On the other hand, even though the faces processed by the blind face restoration methods show appealing quality, there inevitably exist gaps between the recovered faces and the real ground-truths. Such gaps may affect the degradation representation accuracy and further hamper the training of the SR model. These problems have a large impact on the SR performance, especially when the model is fine-tuned for image-specific super-resolution." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 60, + 213, + 282, + 366 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 213, + 282, + 366 + ], + "spans": [ + { + "bbox": [ + 60, + 213, + 282, + 366 + ], + "type": "text", + "content": "To remedy the aforementioned problems regarding training efforts and data gaps, we propose an efficient and effective method dubbed MetaF2N. In specific, the SR model directly fine-tunes the parameters from the low-quality and recovered face pairs, then uses the fine-tuned parameters to process the whole natural image. As such, the cumbersome degradation extraction and low-quality image synthesis steps are circumvented in our method, which avoids the interference of degradation modeling errors. In order to stabilize and accelerate the fine-tuning process during inference, we adopt the model-agnostic meta-learning [11] framework in the training phase, resulting in a much more practical model adaptation procedure that can be finished in a single fine-tuning step." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 60, + 366, + 282, + 549 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 366, + 282, + 549 + ], + "spans": [ + { + "bbox": [ + 60, + 366, + 282, + 549 + ], + "type": "text", + "content": "Additionally, considering the gaps between low-quality faces and that processed by blind face restoration methods, we argue that treating all pixels equally will magnify the effect of the errors. Therefore, we further deploy a MaskNet, which adaptively predicts loss weights for different positions, to fulfill that the recovered face regions more similar to the ground-truths are assigned with higher loss weights. Ideally, the weight map should be extracted from the recovered faces and the ground-truths. Unfortunately, the ground-truths are unavailable during inference. Considering that predicting the loss weight map is similar to the image quality assessment (IQA) task, following the idea of degraded-reference IQA methods [2, 62], the MaskNet instead takes the low-quality and recovered faces as input. According to our observation, typically the areas closer to the ground-truth are assigned with larger weights and vice versa, which is consistent with the intuitions." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 60, + 551, + 280, + 648 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 551, + 280, + 648 + ], + "spans": [ + { + "bbox": [ + 60, + 551, + 280, + 648 + ], + "type": "text", + "content": "For evaluating the proposed MetaF2N, we have constructed several synthetic datasets based on FFHQ [21] and CelebA [34]. To further show the effectiveness under real-world scenarios, we have also collected a real-world low-quality image dataset from the Internet and existing datasets, namely RealFaces200 (RF200), which contains a single face or multiple faces in each image. Extensive experiments show that our MetaF2N achieves superior performance on both synthetic and real-world datasets." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 71, + 650, + 263, + 660 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 650, + 263, + 660 + ], + "spans": [ + { + "bbox": [ + 71, + 650, + 263, + 660 + ], + "type": "text", + "content": "In summary, the contribution of this paper includes," + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 71, + 667, + 282, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 667, + 282, + 711 + ], + "spans": [ + { + "bbox": [ + 71, + 667, + 282, + 711 + ], + "type": "text", + "content": "- We propose an efficient and effective method dubbed MetaF2N for blind image super-resolution, which takes advances of blind face restoration models and learns model adaptation from the face regions with" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 315, + 126, + 412, + 137 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 126, + 412, + 137 + ], + "spans": [ + { + "bbox": [ + 315, + 126, + 412, + 137 + ], + "type": "text", + "content": "only one fine-tuning step." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 307, + 143, + 517, + 239 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 307, + 143, + 516, + 198 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 143, + 516, + 198 + ], + "spans": [ + { + "bbox": [ + 307, + 143, + 516, + 198 + ], + "type": "text", + "content": "- Considering that the gaps between faces recovered by blind face restoration methods and the ground-truth ones may result in an inaccurate degradation modeling, a MaskNet is introduced for confidence prediction to mitigate the effect of the gaps." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 307, + 206, + 517, + 239 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 206, + 517, + 239 + ], + "spans": [ + { + "bbox": [ + 307, + 206, + 517, + 239 + ], + "type": "text", + "content": "- A real-world low-quality image dataset with one or multiple faces in each image is collected, which will be helpful for face-guided blind image super-resolution." + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 297, + 248, + 377, + 261 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 248, + 377, + 261 + ], + "spans": [ + { + "bbox": [ + 297, + 248, + 377, + 261 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 267, + 517, + 344 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 267, + 517, + 344 + ], + "spans": [ + { + "bbox": [ + 296, + 267, + 517, + 344 + ], + "type": "text", + "content": "Recent efforts on blind image SR are mainly devoted to network design and data construction. We recommend [9, 33] for a comprehensive review of blind image SR, and focus on the most relevant methods of data construction, which are orthogonal to network design. We also briefly review recent advances in blind face restoration and meta-learning, which settle the foundation of this work." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 297, + 351, + 448, + 362 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 351, + 448, + 362 + ], + "spans": [ + { + "bbox": [ + 297, + 351, + 448, + 362 + ], + "type": "text", + "content": "2.1. Blind Image Super-Resolution" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 367, + 517, + 597 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 367, + 517, + 597 + ], + "spans": [ + { + "bbox": [ + 296, + 367, + 517, + 597 + ], + "type": "text", + "content": "Pairwise Data. Recent methods have made great efforts towards pairwise datasets that cover a wider range of real-world degradations and are better aligned. The most intuitive way is to collect pairwise samples. For example, Chen et al. [8] collected a City100 dataset by a DSLR and a smartphone via focal length and shooting distance adjustment, respectively. Since City100 was captured via postcards ignoring the geometries, Cai et al. [5] and Wei et al. [55] proposed to capture image pairs in real-world scenes and collected two datasets RealSR and DRealSR. Joze et al. [20] instead captured a dataset ImagePairs by embedding two cameras with different resolutions into a beam splitter. Another approach is to synthesize low-quality images from high-quality ones. Early methods [15, 18, 19, 53] utilized classical degradation models composed of blur, down-sampling, noise, etc., which are insufficient to model the real-world degradations. Zhang et al. [59] and Wang et al. [51] proposed to mimic real-world degradations via random combinations of different degradations. Albeit their progress on general image SR, these methods still cover a limited and biased range of real-world degradations." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 296, + 602, + 517, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 602, + 517, + 711 + ], + "spans": [ + { + "bbox": [ + 296, + 602, + 517, + 711 + ], + "type": "text", + "content": "Unpaired Data. For better utilizing unpaired low-quality images that are easier to collect, some methods [12, 49, 58] proposed to extract the degradation representations or directly learn low-quality image synthesis in an unsupervised manner. Some methods [42, 47] utilized the texture recurrence across different scales or the priors embraced in the model learning process, and achieved image-specific blind image super-resolution in a self-supervised scheme. Purely relying on the unpaired samples or solely the low-quality ones, these methods may cover more degradations yet have" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "spans": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "type": "text", + "content": "13034" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 60, + 125, + 281, + 213 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 125, + 281, + 213 + ], + "spans": [ + { + "bbox": [ + 60, + 125, + 281, + 213 + ], + "type": "text", + "content": "unsatisfactory performance in most cases. As a compromise, Li et al. [26] utilized the highly structured faces in real-world low-quality images, and extracted degradation representations from the low-quality faces and their counterparts recovered by blind face restoration methods. In this work, we take a step forward to solve the problems of Li et al. [26] and propose a MetaF2N framework for effective blind image SR of LR natural images containing faces." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 61, + 221, + 180, + 232 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 221, + 180, + 232 + ], + "spans": [ + { + "bbox": [ + 61, + 221, + 180, + 232 + ], + "type": "text", + "content": "2.2. Blind Face Restoration" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 60, + 239, + 282, + 436 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 239, + 282, + 436 + ], + "spans": [ + { + "bbox": [ + 60, + 239, + 282, + 436 + ], + "type": "text", + "content": "The diverse structures and complicated degradation jointly exacerbate the difficulties of blind natural image SR. In contrast, recent methods tend to leverage the structure information of specific images (e.g., faces [27-30, 57, 63] and text [31]), which have exhibited superior performance. Li et al. [28, 29] suggested using high-quality image(s) of the same person to provide personalized guidance. More general face restoration methods focused on constructing dictionaries [16, 27, 30, 54], semantic maps [7], or codebooks [63]. Recently, the generative structure prior based methods [6, 50, 57, 64] leveraged the representative pretrained StyleGAN models [22] and showed tremendous improvement in restoring fine-grained textures. Compared with natural images, these methods showed great generalization abilities, even in the presence of unknown degradations. This property has motivated us to employ face images on the inner loop of meta-learning to benefit the optimization toward better natural image SR." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 61, + 444, + 274, + 456 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 444, + 274, + 456 + ], + "spans": [ + { + "bbox": [ + 61, + 444, + 274, + 456 + ], + "type": "text", + "content": "2.3. Image Super-Resolution with Meta-Learning" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 60, + 462, + 281, + 648 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 462, + 281, + 648 + ], + "spans": [ + { + "bbox": [ + 60, + 462, + 281, + 648 + ], + "type": "text", + "content": "Meta-learning aims to learn adaptation to new domains or tasks by leveraging existing ones, which has demonstrated excellent generalization ability in many tasks [11, 14, 37, 40, 44, 45, 48]. Early works like MZSR [43] and MLSR [41] utilized meta-learning techniques to obtain a better initialization of model parameters that can be efficiently adapted to new low-quality images. Meta-KernelGAN [25] utilized meta-learning for efficient kernel estimation, which can be combined with non-blind SR methods. As one can see, MZSR [43] and MLSR [41] heavily rely on known degradations to construct inner loop supervisions, while Meta-KernelGAN is also restricted due to that the degradation representations formulated by kernels cannot well describe many real-world degradations. In this work, we adopt face regions as inner loop supervision and get rid of explicit degradation representations, which is more practical for real-world scenarios." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 61, + 659, + 131, + 671 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 659, + 131, + 671 + ], + "spans": [ + { + "bbox": [ + 61, + 659, + 131, + 671 + ], + "type": "text", + "content": "3. Preliminary" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 60, + 677, + 280, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 677, + 280, + 711 + ], + "spans": [ + { + "bbox": [ + 60, + 677, + 280, + 711 + ], + "type": "text", + "content": "For efficiently utilizing the generalization ability of face restoration methods in blind image SR and achieving flexibility on image-specific degradations, we have designed our" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 296, + 125, + 517, + 169 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 125, + 517, + 169 + ], + "spans": [ + { + "bbox": [ + 296, + 125, + 517, + 169 + ], + "type": "text", + "content": "MetaF2N using the model-agnostic meta-learning framework (MAML) [11]. In this section, we briefly introduce the meta-learning framework based on MAML, which will be helpful for understanding our method." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 296, + 169, + 517, + 213 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 169, + 517, + 213 + ], + "spans": [ + { + "bbox": [ + 296, + 169, + 517, + 213 + ], + "type": "text", + "content": "Typically, a deep model " + }, + { + "bbox": [ + 296, + 169, + 517, + 213 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 296, + 169, + 517, + 213 + ], + "type": "text", + "content": " is trained by a learning objective " + }, + { + "bbox": [ + 296, + 169, + 517, + 213 + ], + "type": "inline_equation", + "content": "\\mathcal{L}" + }, + { + "bbox": [ + 296, + 169, + 517, + 213 + ], + "type": "text", + "content": ", which is directly dependent on the purpose of the task (e.g., " + }, + { + "bbox": [ + 296, + 169, + 517, + 213 + ], + "type": "inline_equation", + "content": "\\ell_1" + }, + { + "bbox": [ + 296, + 169, + 517, + 213 + ], + "type": "text", + "content": " loss for fidelity in image SR tasks), and the optimal parameter " + }, + { + "bbox": [ + 296, + 169, + 517, + 213 + ], + "type": "inline_equation", + "content": "\\theta^*" + }, + { + "bbox": [ + 296, + 169, + 517, + 213 + ], + "type": "text", + "content": " is obtained via" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 354, + 218, + 516, + 234 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 354, + 218, + 516, + 234 + ], + "spans": [ + { + "bbox": [ + 354, + 218, + 516, + 234 + ], + "type": "interline_equation", + "content": "\\theta^ {*} = \\arg \\min _ {\\theta} \\mathcal {L} (f (\\mathbf {x}; \\theta), \\mathbf {y}), \\tag {1}", + "image_path": "094e4e7ad6b85e6d9ff07c919cb43be69f4ac14a9ade378eed6a8c8c76af72b8.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 239, + 516, + 261 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 239, + 516, + 261 + ], + "spans": [ + { + "bbox": [ + 296, + 239, + 516, + 261 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 296, + 239, + 516, + 261 + ], + "type": "inline_equation", + "content": "\\mathbf{x}" + }, + { + "bbox": [ + 296, + 239, + 516, + 261 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 296, + 239, + 516, + 261 + ], + "type": "inline_equation", + "content": "\\mathbf{y}" + }, + { + "bbox": [ + 296, + 239, + 516, + 261 + ], + "type": "text", + "content": " are input and ground-truth. Intuitively, the objective of Eqn. (1) is to get a " + }, + { + "bbox": [ + 296, + 239, + 516, + 261 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 296, + 239, + 516, + 261 + ], + "type": "text", + "content": " leading to the lowest " + }, + { + "bbox": [ + 296, + 239, + 516, + 261 + ], + "type": "inline_equation", + "content": "\\mathcal{L}" + }, + { + "bbox": [ + 296, + 239, + 516, + 261 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 261, + 516, + 304 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 261, + 516, + 304 + ], + "spans": [ + { + "bbox": [ + 296, + 261, + 516, + 304 + ], + "type": "text", + "content": "Instead, MAML [11] aims to learn a parameter " + }, + { + "bbox": [ + 296, + 261, + 516, + 304 + ], + "type": "inline_equation", + "content": "\\theta^{*}" + }, + { + "bbox": [ + 296, + 261, + 516, + 304 + ], + "type": "text", + "content": ", which can be efficiently fine-tuned toward the test sample with one or several steps. Taking the one-step situation as an example, the learning objective can be written as" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 309, + 309, + 516, + 337 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 309, + 309, + 516, + 337 + ], + "spans": [ + { + "bbox": [ + 309, + 309, + 516, + 337 + ], + "type": "interline_equation", + "content": "\\theta^ {*} = \\arg \\min _ {\\theta} \\sum_ {T _ {i} \\sim p (T)} \\mathcal {L} ^ {T _ {i}} \\left(f (\\mathbf {x}; \\theta - \\alpha \\frac {\\partial \\mathcal {L} _ {i n} ^ {T _ {i}}}{\\partial \\theta}), \\mathbf {y}\\right), \\tag {2}", + "image_path": "15e233e1cd1c6ad594d2722cbc37aee3fcf58493ef3a47374e47386265406673.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "spans": [ + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "inline_equation", + "content": "p(T),\\mathcal{L}_{in}^{T_i}" + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "text", + "content": " , and " + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "text", + "content": " respectively represent the distribution (or collection) of tasks, the inner loop loss function for the task " + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "inline_equation", + "content": "T_{i}" + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "text", + "content": " , and learning rate for the inner loop. Here, we can regard " + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "inline_equation", + "content": "\\theta -\\alpha \\frac{\\partial\\mathcal{L}_{in}^{T_i}}{\\partial\\theta}" + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "text", + "content": " as a whole. Then, similar to Eqn. (1), the objective of Eqn. (2) can be interpreted as to get a " + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "text", + "content": " leading to the lowest " + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "inline_equation", + "content": "\\mathcal{L}^{T_i}" + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "text", + "content": " after one back-propagation step w.r.t. " + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{in}^{T_i}" + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "text", + "content": " . In other words, a model trained under the MAML settings can adapt to new domains or tasks with a limited number of fine-tuning steps (i.e., " + }, + { + "bbox": [ + 296, + 342, + 517, + 451 + ], + "type": "inline_equation", + "content": "\\theta -\\alpha \\frac{\\partial\\mathcal{L}_{in}^{T_i}}{\\partial\\theta})" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 297, + 458, + 348, + 468 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 458, + 348, + 468 + ], + "spans": [ + { + "bbox": [ + 297, + 458, + 348, + 468 + ], + "type": "text", + "content": "4. Method" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 296, + 475, + 516, + 531 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 475, + 516, + 531 + ], + "spans": [ + { + "bbox": [ + 296, + 475, + 516, + 531 + ], + "type": "text", + "content": "In this work, we aim to obtain a blind image SR model " + }, + { + "bbox": [ + 296, + 475, + 516, + 531 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 296, + 475, + 516, + 531 + ], + "type": "text", + "content": " which can be efficiently adapted to process the degradation of a real-world low-quality image " + }, + { + "bbox": [ + 296, + 475, + 516, + 531 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}" + }, + { + "bbox": [ + 296, + 475, + 516, + 531 + ], + "type": "text", + "content": " under the guidance of its face regions (denoted by " + }, + { + "bbox": [ + 296, + 475, + 516, + 531 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}^{\\ominus}" + }, + { + "bbox": [ + 296, + 475, + 516, + 531 + ], + "type": "text", + "content": ") and the faces processed by blind face restoration methods (denoted by " + }, + { + "bbox": [ + 296, + 475, + 516, + 531 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{BFR}^{\\ominus}" + }, + { + "bbox": [ + 296, + 475, + 516, + 531 + ], + "type": "text", + "content": ")." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 296, + 531, + 517, + 575 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 531, + 517, + 575 + ], + "spans": [ + { + "bbox": [ + 296, + 531, + 517, + 575 + ], + "type": "text", + "content": "Considering the complex and wide-range degradations in real-world low-quality images, we take advantage of MAML to design our method for processing image-specific degradations. Then Eqn. (2) can be rewritten as," + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 580, + 516, + 607 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 580, + 516, + 607 + ], + "spans": [ + { + "bbox": [ + 306, + 580, + 516, + 607 + ], + "type": "interline_equation", + "content": "\\theta^ {*} = \\arg \\min _ {\\theta} \\sum_ {T _ {i} \\sim p (T)} \\mathcal {L} ^ {T _ {i}} \\left(f \\left(\\mathbf {I} _ {L R}; \\theta - \\alpha \\frac {\\partial \\mathcal {L} _ {i n} ^ {T _ {i}}}{\\partial \\theta}\\right), \\mathbf {I}\\right), \\tag {3}", + "image_path": "efe8718bcb685ad418cb3e6e6a5ca3a3cf8b167770e26b8ddc66f92dec21878c.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "spans": [ + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "inline_equation", + "content": "p(T)" + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "text", + "content": " is the distribution of different degradations, " + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "inline_equation", + "content": "T_{i}" + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "text", + "content": " is the task for one specific degradation, " + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "text", + "content": " is the parameter of " + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "inline_equation", + "content": "\\mathbf{I}" + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "text", + "content": " denotes the ground-truth image. The design of " + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{in}^{T_i}" + }, + { + "bbox": [ + 296, + 612, + 517, + 656 + ], + "type": "text", + "content": " will be given in Sec. 4.1." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 297, + 661, + 399, + 673 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 661, + 399, + 673 + ], + "spans": [ + { + "bbox": [ + 297, + 661, + 399, + 673 + ], + "type": "text", + "content": "4.1. Inner Loop Design" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 296, + 677, + 517, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 677, + 517, + 711 + ], + "spans": [ + { + "bbox": [ + 296, + 677, + 517, + 711 + ], + "type": "text", + "content": "One of the key factors of applying MAML [11] to blind image SR tasks is the design of " + }, + { + "bbox": [ + 296, + 677, + 517, + 711 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{in}^{T_i}" + }, + { + "bbox": [ + 296, + 677, + 517, + 711 + ], + "type": "text", + "content": " in Eqn. (3). Specifically, for adapting to the new degradation of an " + }, + { + "bbox": [ + 296, + 677, + 517, + 711 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}" + }, + { + "bbox": [ + 296, + 677, + 517, + 711 + ], + "type": "text", + "content": ", the" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "spans": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "type": "text", + "content": "13035" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 75, + 123, + 503, + 244 + ], + "blocks": [ + { + "bbox": [ + 75, + 123, + 503, + 244 + ], + "lines": [ + { + "bbox": [ + 75, + 123, + 503, + 244 + ], + "spans": [ + { + "bbox": [ + 75, + 123, + 503, + 244 + ], + "type": "image", + "image_path": "b7ef4561c43c31ea7a84af1464be0e372dac16294c2821e8a554c3a121114ce7.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "lines": [ + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "spans": [ + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "type": "text", + "content": "Figure 1: Pipeline of the proposed MetaF2N framework. During inference, the inner loop updates the initial parameter " + }, + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "type": "text", + "content": " via a back-propagation step (dotted blue line), and the obtained " + }, + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "type": "inline_equation", + "content": "\\theta_{n}" + }, + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "type": "text", + "content": " is used to process the whole natural image in the outer loop. For training, the parameter update indeed relies on the gradients of outer loop loss " + }, + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "type": "inline_equation", + "content": "\\mathcal{L}^{T_i}" + }, + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "type": "text", + "content": " w.r.t. the initial parameter " + }, + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "type": "text", + "content": " and the MaskNet parameter " + }, + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "type": "inline_equation", + "content": "\\theta_{\\mathbf{m}}" + }, + { + "bbox": [ + 60, + 248, + 518, + 303 + ], + "type": "text", + "content": " (dotted red line). For easier understanding, the steps of the pipeline (remarked by circled numbers) are introduced in Sec. 4.3. Please refer to Algorithms 1 and 2 for more details about the training and inference process." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "spans": [ + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "text", + "content": "data for calculating " + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{in}^{T_i}" + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "text", + "content": " should have the same distribution as " + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}" + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "text", + "content": ". For MAML-based non-blind image SR methods [41, 43], one can construct inner loop data by further down-sampling " + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}" + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "text", + "content": " with the known degradation " + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "text", + "content": " to get " + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LLR} = d(\\mathbf{I}_{LR})" + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "text", + "content": ". Then assuming the inner loop loss function to be " + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "inline_equation", + "content": "\\ell_1" + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "text", + "content": ", we can obtain " + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{in}^{T_i} = \\| f(\\mathbf{I}_{LLR};\\theta) - \\mathbf{I}_{LR}\\|_1" + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "text", + "content": ". However, for blind image SR, it is almost impossible to get extra image pairs with the same degradation as " + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}" + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "text", + "content": " since " + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "inline_equation", + "content": "d" + }, + { + "bbox": [ + 60, + 318, + 282, + 417 + ], + "type": "text", + "content": " is unknown." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "spans": [ + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "text", + "content": "Inspired by ReDegNet [26], which shows that faces can be utilized to extract the degradation representation for the whole image, we directly construct the inner loop data with the face regions. Thanks to the great generalization ability of blind face restoration methods [6,50,57,64], we are able to obtain a pseudo ground-truth for the face regions, which is denoted by " + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{BFR}^{\\ominus} = f_{BFR}(\\mathbf{I}_{LR}^{\\ominus};\\theta_{BFR})" + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "text", + "content": " , where " + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "inline_equation", + "content": "f_{BFR}" + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "text", + "content": " is the blind face restoration model with pre-trained parameter " + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "inline_equation", + "content": "\\theta_{BFR}" + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "text", + "content": " . In this paper, we follow ReDegNet [26] and adopt GPEN [57] as " + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "inline_equation", + "content": "f_{BFR}" + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "text", + "content": " . With the low-quality face regions " + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}^{\\ominus}" + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "text", + "content": " and the recovered " + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{BFR}^{\\ominus}" + }, + { + "bbox": [ + 60, + 418, + 282, + 549 + ], + "type": "text", + "content": " , the inner loop loss function can be defined by" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 114, + 559, + 280, + 573 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 114, + 559, + 280, + 573 + ], + "spans": [ + { + "bbox": [ + 114, + 559, + 280, + 573 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {i n} ^ {T _ {i}} = \\left\\| f \\left(\\mathbf {I} _ {L R} ^ {\\ominus}; \\theta\\right) - \\mathbf {I} _ {B F R} ^ {\\ominus} \\right\\| _ {1}. \\tag {4}", + "image_path": "398eeeed66daa916844bec7b5065cd8fe3c68b78cf3cc784c8a02c0238071d21.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 60, + 582, + 252, + 595 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 582, + 252, + 595 + ], + "spans": [ + { + "bbox": [ + 60, + 582, + 252, + 595 + ], + "type": "text", + "content": "4.2. Adaptive Loss Weighting with MaskNet" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 60, + 600, + 280, + 667 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 600, + 280, + 667 + ], + "spans": [ + { + "bbox": [ + 60, + 600, + 280, + 667 + ], + "type": "text", + "content": "Despite the appealing visual quality of recent blind face restoration methods, there inevitably exist gaps between generated faces " + }, + { + "bbox": [ + 60, + 600, + 280, + 667 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{BFR}^{\\ominus}" + }, + { + "bbox": [ + 60, + 600, + 280, + 667 + ], + "type": "text", + "content": " and ground-truth ones " + }, + { + "bbox": [ + 60, + 600, + 280, + 667 + ], + "type": "inline_equation", + "content": "\\mathbf{I}^{\\ominus}" + }, + { + "bbox": [ + 60, + 600, + 280, + 667 + ], + "type": "text", + "content": ". For inaccurate regions, the degradation either explicitly (ReDeg-Net [26]) or implicitly (Our MetaF2N) described by the " + }, + { + "bbox": [ + 60, + 600, + 280, + 667 + ], + "type": "inline_equation", + "content": "(\\mathbf{I}_{LR}^{\\ominus},\\mathbf{I}_{BFR}^{\\ominus})" + }, + { + "bbox": [ + 60, + 600, + 280, + 667 + ], + "type": "text", + "content": " pair also deviate from that by " + }, + { + "bbox": [ + 60, + 600, + 280, + 667 + ], + "type": "inline_equation", + "content": "(\\mathbf{I}_{LR}^{\\ominus},\\mathbf{I}^{\\ominus})" + }, + { + "bbox": [ + 60, + 600, + 280, + 667 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 60, + 667, + 281, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 667, + 281, + 712 + ], + "spans": [ + { + "bbox": [ + 60, + 667, + 281, + 712 + ], + "type": "text", + "content": "However, different regions of " + }, + { + "bbox": [ + 60, + 667, + 281, + 712 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{BFR}^{\\odot}" + }, + { + "bbox": [ + 60, + 667, + 281, + 712 + ], + "type": "text", + "content": " are treated equally in Eqn. (4), which will have negative effect on the final results. As a remedy, we propose to predict loss weights adaptively for different regions via a MaskNet. With the weight map" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 297, + 319, + 512, + 330 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 319, + 512, + 330 + ], + "spans": [ + { + "bbox": [ + 297, + 319, + 512, + 330 + ], + "type": "text", + "content": "m generated by the MaskNet, Eqn. (4) can be rewritten as" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 339, + 335, + 516, + 349 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 339, + 335, + 516, + 349 + ], + "spans": [ + { + "bbox": [ + 339, + 335, + 516, + 349 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {i n} ^ {T _ {i}} = \\left\\| \\mathbf {m} \\cdot \\left(f \\left(\\mathbf {I} _ {L R} ^ {\\ominus}; \\theta\\right) - \\mathbf {I} _ {B F R} ^ {\\ominus}\\right) \\right\\| _ {1}. \\tag {5}", + "image_path": "9f9625c99303a2f620daddfe587e897dbcac0a7e5cd6723fc498c191288cc209.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "spans": [ + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "text", + "content": "Ideally, " + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "inline_equation", + "content": "\\mathbf{m}" + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "text", + "content": " should be generated from the " + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "inline_equation", + "content": "(\\mathbf{I}_{BFR}^{\\odot},\\mathbf{I}^{\\odot})" + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "text", + "content": " pair. Unfortunately, " + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "inline_equation", + "content": "\\mathbf{I}" + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "text", + "content": " is unavailable for test samples, a possible solution is solely predicting from " + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{BFR}^{\\odot}" + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "text", + "content": ", yet the improvement is marginal. Analogous to degraded-reference IQA [2, 62] which predicts IQA metrics from (input, output) pairs rather than (output, GT) pairs in full-reference IQA, we predict " + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "inline_equation", + "content": "\\mathbf{m}" + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "text", + "content": " from the " + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "inline_equation", + "content": "(\\mathbf{I}_{LR}^{\\odot},\\mathbf{I}_{BFR}^{\\odot})" + }, + { + "bbox": [ + 296, + 354, + 517, + 432 + ], + "type": "text", + "content": " pair, i.e.," + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 357, + 436, + 516, + 450 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 357, + 436, + 516, + 450 + ], + "spans": [ + { + "bbox": [ + 357, + 436, + 516, + 450 + ], + "type": "interline_equation", + "content": "\\mathbf {m} = f _ {\\mathbf {m}} \\left(\\mathbf {I} _ {L R} ^ {\\prime}, \\mathbf {I} _ {B F R} ^ {\\prime}; \\theta_ {\\mathbf {m}}\\right), \\tag {6}", + "image_path": "8e74e6ba78af7f161f3d5e089584f6fba77060e2deb32a6d672f936c2125cc37.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 296, + 455, + 517, + 511 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 455, + 517, + 511 + ], + "spans": [ + { + "bbox": [ + 296, + 455, + 517, + 511 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 296, + 455, + 517, + 511 + ], + "type": "inline_equation", + "content": "f_{\\mathbf{m}}" + }, + { + "bbox": [ + 296, + 455, + 517, + 511 + ], + "type": "text", + "content": " is the MaskNet, which is a simple network composed of 8 convolution layers shown in Fig. 2. As further shown in the ablation studies, the degraded-reference solution in Eqn. (6) performs better than solely predicting from " + }, + { + "bbox": [ + 296, + 455, + 517, + 511 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{BFR}^{\\odot}" + }, + { + "bbox": [ + 296, + 455, + 517, + 511 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 297, + 516, + 491, + 527 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 516, + 491, + 527 + ], + "spans": [ + { + "bbox": [ + 297, + 516, + 491, + 527 + ], + "type": "text", + "content": "4.3. Overall Pipeline and Learning Objective" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "spans": [ + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "text", + "content": "With the inner loop designed in Eqn. (5), we can build the pipeline as shown in Fig. 1. In specific, given a low-quality image " + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}" + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "text", + "content": " containing face regions denoted by " + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}^{\\ominus}" + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "text", + "content": ", we pass " + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}^{\\ominus}" + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "text", + "content": " through the SR network " + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "text", + "content": " and obtain the inner loop result " + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{SR}^{\\ominus}" + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "text", + "content": ". For a fair comparison against existing methods, we take the model of Real-ESRGAN [53] as the SR network, whose parameter is used to initialize the " + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "text", + "content": " in the inner loop. To construct supervision for the inner loop, we use a pre-trained GPEN [57] model, whose parameter is kept fixed in our whole pipeline. Then we can obtain the weight map " + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "inline_equation", + "content": "\\mathbf{m}" + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "text", + "content": " following Eqn. (6), as well as the inner loop loss " + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{in}^{T_i}" + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "text", + "content": " following Eqn. (5), which can be used to generate a temporary parameter " + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "inline_equation", + "content": "\\theta_{\\mathrm{n}} = \\theta -\\alpha \\frac{\\partial\\mathcal{L}_{in}^{T_i}}{\\partial\\theta}" + }, + { + "bbox": [ + 296, + 532, + 517, + 691 + ], + "type": "text", + "content": " for processing the whole natural image in the outer loop, i.e.," + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 324, + 695, + 517, + 713 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 324, + 695, + 517, + 713 + ], + "spans": [ + { + "bbox": [ + 324, + 695, + 517, + 713 + ], + "type": "interline_equation", + "content": "\\mathbf {I} _ {S R} = f \\left(\\mathbf {I} _ {L R}; \\theta_ {\\mathbf {n}}\\right) = f \\left(\\mathbf {I} _ {L R}; \\theta - \\alpha \\frac {\\partial \\mathcal {L} _ {i n} ^ {T _ {i}}}{\\partial \\theta}\\right) ⑥. \\tag {7}", + "image_path": "12767cf6c6ff94a019e3973814f4f61a5f8222885eea097f58dfe98fe5fd0b17.jpg" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "spans": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "type": "text", + "content": "13036" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "type": "code", + "bbox": [ + 63, + 140, + 279, + 459 + ], + "blocks": [ + { + "bbox": [ + 67, + 127, + 230, + 138 + ], + "lines": [ + { + "bbox": [ + 67, + 127, + 230, + 138 + ], + "spans": [ + { + "bbox": [ + 67, + 127, + 230, + 138 + ], + "type": "text", + "content": "Algorithm 1: Training Process of MetaF2N" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "code_caption" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "lines": [ + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "spans": [ + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": "Input: Distribution of different degradation restoration tasks " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "p(T)" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " High-quality natural image dataset " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{HR}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " High-quality face dataset " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{\\odot}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " Learning rates " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\alpha ,\\beta ,\\gamma ,\\eta" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " Output: Model parameter " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\theta ,\\theta_{\\mathbf{m}}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " 1 Initialize " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "f,D" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\theta ,\\theta_{D}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " from Real-ESRGAN [51] 2 Initialize " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "f_{BFR}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\theta_{BFR}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " from GPEN [57] 3 Random initialize " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "f_{\\mathbf{m}}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\theta_{\\mathbf{m}}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " 4 for all training steps do 5 Sample batch of tasks " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "T_{i}\\sim p(T)" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " 6 for all " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "T_{i}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " do 7 Sample images " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\mathbf{I},\\mathbf{I}^{\\odot}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{\\mathcal{H}\\mathcal{R}}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{\\odot}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " 8 Create " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\mathbf{I},\\mathbf{I}_{LR},\\mathbf{I}_{LR}^{\\odot}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " of " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "T_{i}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " 9 " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{BFR}^{\\odot} = f_{BFR}(\\mathbf{I}_{LR}^{\\odot};\\theta_{BFR})" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " m " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "= f_{\\mathrm{m}}(\\mathbf{I}_{LR}^{\\odot},\\mathbf{I}_{BFR}^{\\odot};\\theta_{\\mathrm{m}})" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " for 1 step of inner loop do 12 " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\begin{array}{r}\\mathcal{L}_{in}^{T_i} = ||\\mathbf{m}\\cdot (f(\\mathbf{I}_{LR}^{\\odot};\\theta) - \\mathbf{I}_{BFR}^{\\odot})||_1\\\\ \\theta_{\\mathrm{n}}\\gets \\theta -\\alpha \\nabla_{\\theta}\\mathcal{L}_{in}^{T_i}(\\theta) \\end{array}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " end 15 " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{SR} = f(\\mathbf{I}_{LR};\\theta_{\\mathbf{n}})" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " 16 " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\mathcal{L}^{T_i}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " is defined as Eqn. (13) 17 " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_D^{T_i}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " is defined as Eqn. (11) end 19 " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\theta \\gets \\theta -\\beta \\nabla_{\\theta}\\sum_{T_i\\sim p(T)}\\mathcal{L}^{T_i}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " 20 " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\theta_{\\mathrm{m}}\\gets \\theta_{\\mathrm{m}} - \\gamma \\nabla_{\\theta_{\\mathrm{m}}}\\sum_{T_i\\sim p(T)}\\mathcal{L}^{T_i}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " 21 " + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "inline_equation", + "content": "\\theta_D\\gets \\theta_D - \\eta \\nabla_{\\theta_D}\\sum_{T_i\\sim p(T)}\\mathcal{L}_D^{T_i}" + }, + { + "bbox": [ + 63, + 140, + 279, + 459 + ], + "type": "text", + "content": " 22 end" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "code_body" + } + ], + "index": 1, + "sub_type": "algorithm" + }, + { + "type": "code", + "bbox": [ + 63, + 490, + 279, + 680 + ], + "blocks": [ + { + "bbox": [ + 67, + 478, + 233, + 488 + ], + "lines": [ + { + "bbox": [ + 67, + 478, + 233, + 488 + ], + "spans": [ + { + "bbox": [ + 67, + 478, + 233, + 488 + ], + "type": "text", + "content": "Algorithm 2: Inference Process of MetaF2N" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "code_caption" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "lines": [ + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "spans": [ + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": "Input: LR test image " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " Trained model parameter " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\theta ,\\theta_{\\mathrm{m}}" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " Pre-trained GPEN [57] parameter " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\theta_{BFR}" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " Fine-tuning steps " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " and learning rate " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " Output: Super-resolved image " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{SR}" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " 1 Initialize " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "f,f_{\\mathbf{m}}" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\theta ,\\theta_{\\mathbf{m}}" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " 2 Initialize " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "f_{BFR}" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\theta_{BFR}" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " from GPEN [57] 3 Extract face regions " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}^{\\ominus}" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " 4 " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{BFR}^{\\ominus} = f_{BFR}(\\mathbf{I}_{LR}^{\\ominus};\\theta_{BFR})" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " 5 " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\mathbf{m} = f_{\\mathbf{m}}(\\mathbf{I}_{LR}^{\\ominus},\\mathbf{I}_{BFR}^{\\ominus};\\theta_{\\mathbf{m}})" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " 6 for n steps of inner loop do 7 " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\begin{array}{rl}{\\mathcal{L}_{in}} & {= \\| \\mathbf{m}\\cdot (f(\\mathbf{I}_{LR}^{\\ominus};\\theta) - \\mathbf{I}_{BFR}^{\\ominus})\\| _1}\\\\ {\\theta} & {\\leftarrow \\theta -\\alpha \\nabla_{\\theta}\\mathcal{L}_{in}(\\theta)} \\end{array}" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " 8 end 9 end 10 " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\theta_{\\mathbf{n}}\\gets \\theta" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " 11 " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{SR} = f(\\mathbf{I}_{LR};\\theta_{\\mathbf{n}})" + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "text", + "content": " 12 return " + }, + { + "bbox": [ + 63, + 490, + 279, + 680 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{SR}" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "code_body" + } + ], + "index": 3, + "sub_type": "algorithm" + }, + { + "type": "image", + "bbox": [ + 304, + 122, + 511, + 236 + ], + "blocks": [ + { + "bbox": [ + 304, + 122, + 511, + 236 + ], + "lines": [ + { + "bbox": [ + 304, + 122, + 511, + 236 + ], + "spans": [ + { + "bbox": [ + 304, + 122, + 511, + 236 + ], + "type": "image", + "image_path": "5bb15bb37c5968ada6f539a3ee404aaac6b6a815ac83fa391f2542df17ada67f.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 323, + 238, + 490, + 249 + ], + "lines": [ + { + "bbox": [ + 323, + 238, + 490, + 249 + ], + "spans": [ + { + "bbox": [ + 323, + 238, + 490, + 249 + ], + "type": "text", + "content": "Figure 2: The network structure of MaskNet." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 297, + 264, + 516, + 297 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 264, + 516, + 297 + ], + "spans": [ + { + "bbox": [ + 297, + 264, + 516, + 297 + ], + "type": "text", + "content": "The above process (as remarked by the circled numbers) describes the pipeline of MetaF2N during inference and the first six steps in the training phase." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 297, + 297, + 516, + 340 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 297, + 516, + 340 + ], + "spans": [ + { + "bbox": [ + 297, + 297, + 516, + 340 + ], + "type": "text", + "content": "For training MetaF2N, we also need to calculate the outer loop loss " + }, + { + "bbox": [ + 297, + 297, + 516, + 340 + ], + "type": "inline_equation", + "content": "⑦" + }, + { + "bbox": [ + 297, + 297, + 516, + 340 + ], + "type": "text", + "content": ", which is composed of fidelity loss " + }, + { + "bbox": [ + 297, + 297, + 516, + 340 + ], + "type": "inline_equation", + "content": "(\\ell_1)" + }, + { + "bbox": [ + 297, + 297, + 516, + 340 + ], + "type": "text", + "content": ", LPIPS loss [60], and GAN loss [13]. In specific, the fidelity loss is" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 371, + 340, + 516, + 352 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 371, + 340, + 516, + 352 + ], + "spans": [ + { + "bbox": [ + 371, + 340, + 516, + 352 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {1} = \\left\\| \\mathbf {I} _ {S R} - \\mathbf {I} \\right\\| _ {1}, \\tag {8}", + "image_path": "04cd5fedde210727137e711aaf643e6c8722c962a588f8e8c32674cb1d4737ff.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 298, + 356, + 418, + 367 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 356, + 418, + 367 + ], + "spans": [ + { + "bbox": [ + 298, + 356, + 418, + 367 + ], + "type": "text", + "content": "and the LPIPS loss is defined by" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 351, + 373, + 516, + 386 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 351, + 373, + 516, + 386 + ], + "spans": [ + { + "bbox": [ + 351, + 373, + 516, + 386 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {L P I P S}} = \\| \\phi (\\mathbf {I} _ {S R}) - \\phi (\\mathbf {I}) \\| _ {2}, \\tag {9}", + "image_path": "8a1faf7b8dc6aff7b8083f82ca1bffabfdf41964598cfcfbe7601465857a4951.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 297, + 392, + 516, + 425 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 392, + 516, + 425 + ], + "spans": [ + { + "bbox": [ + 297, + 392, + 516, + 425 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 297, + 392, + 516, + 425 + ], + "type": "inline_equation", + "content": "\\phi" + }, + { + "bbox": [ + 297, + 392, + 516, + 425 + ], + "type": "text", + "content": " is the pre-trained AlexNet [24] feature extractor for calculating LPIPS. The adversarial loss follows the setting of Real-ESRGAN [51], which is defined by," + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 356, + 431, + 516, + 444 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 356, + 431, + 516, + 444 + ], + "spans": [ + { + "bbox": [ + 356, + 431, + 516, + 444 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {a d v}} = - \\mathbb {E} [ \\log (D (\\mathbf {I} _ {S R})) ], \\tag {10}", + "image_path": "3d435f6efc5a2c5024fe35e3612b35ea9abda23a4e7459f34934fa59fe52de7e.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 297, + 449, + 516, + 471 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 449, + 516, + 471 + ], + "spans": [ + { + "bbox": [ + 297, + 449, + 516, + 471 + ], + "type": "text", + "content": "where the discriminator " + }, + { + "bbox": [ + 297, + 449, + 516, + 471 + ], + "type": "inline_equation", + "content": "D" + }, + { + "bbox": [ + 297, + 449, + 516, + 471 + ], + "type": "text", + "content": " is iteratively trained along with the SR network, i.e.," + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 318, + 478, + 516, + 491 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 318, + 478, + 516, + 491 + ], + "spans": [ + { + "bbox": [ + 318, + 478, + 516, + 491 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {D} = - \\mathbb {E} [ \\log (D (\\mathbf {I})) - \\log (1 - D (\\mathbf {I} _ {S R})) ]. \\tag {11}", + "image_path": "8866068060b63bb9d41577ff89c893935784bd3648f65ff089e6f845ab02af3f.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 297, + 496, + 516, + 562 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 496, + 516, + 562 + ], + "spans": [ + { + "bbox": [ + 297, + 496, + 516, + 562 + ], + "type": "text", + "content": "Note that some works [25,32] have explored training GANs under the meta-learning structure, and all of them update the discriminator loss in both the inner loop and outer loop. However, to accelerate the training process and save memory, we only update the discriminator loss in the outer loop, which also shows satisfactory results." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 297, + 562, + 516, + 595 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 562, + 516, + 595 + ], + "spans": [ + { + "bbox": [ + 297, + 562, + 516, + 595 + ], + "type": "text", + "content": "To improve the numerical stability and avoid gradient exploding/vanishing, we constrain the MaskNet " + }, + { + "bbox": [ + 297, + 562, + 516, + 595 + ], + "type": "inline_equation", + "content": "f_{\\mathbf{m}}" + }, + { + "bbox": [ + 297, + 562, + 516, + 595 + ], + "type": "text", + "content": " via a regularization term, which is defined by" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 370, + 602, + 516, + 614 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 370, + 602, + 516, + 614 + ], + "spans": [ + { + "bbox": [ + 370, + 602, + 516, + 614 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {r e g}} = \\| \\mathbf {m} - \\mathbf {1} \\| _ {2}. \\tag {12}", + "image_path": "b6c2a0ad09e5c20c1a313b65b7ec779c9b949bd9bb2823433a06af4fe12bdbde.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 297, + 619, + 516, + 642 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 619, + 516, + 642 + ], + "spans": [ + { + "bbox": [ + 297, + 619, + 516, + 642 + ], + "type": "text", + "content": "In summary, the learning objective of our MetaF2N (i.e., the outer loop loss) is" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 311, + 648, + 516, + 661 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 648, + 516, + 661 + ], + "spans": [ + { + "bbox": [ + 311, + 648, + 516, + 661 + ], + "type": "interline_equation", + "content": "\\mathcal {L} ^ {T _ {\\mathrm {i}}} = \\lambda_ {1} \\mathcal {L} _ {1} + \\lambda_ {2} \\mathcal {L} _ {\\text {L P I I P S}} + \\lambda_ {3} \\mathcal {L} _ {\\text {a d v}} + \\lambda_ {4} \\mathcal {L} _ {\\text {r e g}}, \\tag {13}", + "image_path": "c216425e80de1278ae235e35dd128c417fe86c573ea834db0bce818be6b9a286.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 297, + 666, + 516, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 666, + 516, + 711 + ], + "spans": [ + { + "bbox": [ + 297, + 666, + 516, + 711 + ], + "type": "text", + "content": "where the hyperparameters " + }, + { + "bbox": [ + 297, + 666, + 516, + 711 + ], + "type": "inline_equation", + "content": "\\lambda_1, \\lambda_2, \\lambda_3" + }, + { + "bbox": [ + 297, + 666, + 516, + 711 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 297, + 666, + 516, + 711 + ], + "type": "inline_equation", + "content": "\\lambda_4" + }, + { + "bbox": [ + 297, + 666, + 516, + 711 + ], + "type": "text", + "content": " are empirically set to 1, 0.5, 0.1, and 0.002, respectively. Please refer to Algorithms 1 and 2 for more details on the training and inference process of the proposed MetaF2N." + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "spans": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "type": "text", + "content": "13037" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 61, + 124, + 135, + 136 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 124, + 135, + 136 + ], + "spans": [ + { + "bbox": [ + 61, + 124, + 135, + 136 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 61, + 142, + 204, + 154 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 142, + 204, + 154 + ], + "spans": [ + { + "bbox": [ + 61, + 142, + 204, + 154 + ], + "type": "text", + "content": "5.1. Dataset and Training Details" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 60, + 159, + 282, + 313 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 159, + 282, + 313 + ], + "spans": [ + { + "bbox": [ + 60, + 159, + 282, + 313 + ], + "type": "text", + "content": "Training Data. For synthesizing data to train the proposed MetaF2N, high-quality facial and natural images are required for inner and outer loop, respectively. It is worth noting that, the requirement on the training data is that " + }, + { + "bbox": [ + 60, + 159, + 282, + 313 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}^{\\odot}" + }, + { + "bbox": [ + 60, + 159, + 282, + 313 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 60, + 159, + 282, + 313 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}" + }, + { + "bbox": [ + 60, + 159, + 282, + 313 + ], + "type": "text", + "content": " share the identical degradation, but they are not necessarily from the same image. Therefore, to better leverage existing high-quality facial and natural image datasets, we use the first 30,000 images of the aligned FFHQ [21] dataset for the inner loop, and adopt DF2K1 with 3,450 images in total for the outer loop following recent blind image SR methods [26, 51, 59]. For a fair comparison against other methods, we follow the degradation setting of RealESRGAN [51] for low-quality image synthesis. More details are given in the supplementary material." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 60, + 317, + 281, + 339 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 317, + 281, + 339 + ], + "spans": [ + { + "bbox": [ + 60, + 317, + 281, + 339 + ], + "type": "text", + "content": "Testing Data. To comprehensively evaluate the proposed MetaF2N, we have constructed several testing datasets." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "spans": [ + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "text", + "content": "Synthetic datasets are built upon the in-the-wild version of FFHQ [21] and CelebA [34], where 1,000 high-quality images are extracted from each dataset, and faces occupy around " + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "inline_equation", + "content": "10\\%" + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "text", + "content": " areas of the whole image on average. With the high-quality images, we first construct two test datasets whose degradations are independent and identically distributed as the training set, which are denoted by " + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "inline_equation", + "content": "\\mathrm{FFHQ}_{iid}" + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "inline_equation", + "content": "\\mathrm{CelebA}_{iid}" + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "text", + "content": ", respectively. For evaluating the generalization ability on out-of-distribution degradations, we further construct " + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "inline_equation", + "content": "\\mathrm{FFHQ}_{ood}" + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "inline_equation", + "content": "\\mathrm{CelebA}_{ood}" + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "text", + "content": " by changing the parameters of the degradation model, e.g., Gaussian blur " + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "inline_equation", + "content": "\\rightarrow" + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "text", + "content": " motion blur, Gaussian/Poisson noise " + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "inline_equation", + "content": "\\rightarrow" + }, + { + "bbox": [ + 60, + 340, + 282, + 481 + ], + "type": "text", + "content": " Speckle noise. The detailed parameters are in the supplementary material." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 60, + 482, + 281, + 537 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 482, + 281, + 537 + ], + "spans": [ + { + "bbox": [ + 60, + 482, + 281, + 537 + ], + "type": "text", + "content": "A real-world dataset RealFaces200 (RF200) is also established for evaluation under a real scenario, which contains 200 real-world low-quality images collected from the Internet or existing datasets (e.g., WIDER FACE [56]), and there are one or multiple faces in each image." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "spans": [ + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": "Implementation Details. The proposed MetaF2N mainly focuses on leveraging meta-learning for efficient model adaptation for blind image SR, which is independent of network architecture and can be incorporated into arbitrary second-order differentiable models. Therefore, we follow Real-ESRGAN [51], BSRGAN [59], and ReDegNet [26] to adopt the architecture of ESRGAN [53]. For training, each image is cropped into patches, and the patch size is " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "128 \\times 128" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": " for the inner loop (i.e., " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}^{\\ominus}" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{BFR}^{\\ominus}" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{SR}^{\\ominus}" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": ") and " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "256 \\times 256" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": " for the outer loop (i.e., " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{LR}" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{SR}" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "\\mathbf{I}" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": "). The Adam [23] optimizer with " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "\\beta_{1} = 0.5" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "\\beta_{2} = 0.999" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": " is adopted. For the SR model " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": ", the learning rate (lr) of the inner and outer loops are " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "1 \\times 10^{-2}" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "3 \\times 10^{-5}" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": ", respectively, while the lr for the discriminator and MaskNet are " + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "inline_equation", + "content": "1 \\times 10^{-4}" + }, + { + "bbox": [ + 60, + 541, + 282, + 694 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 297, + 125, + 517, + 146 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 125, + 517, + 146 + ], + "spans": [ + { + "bbox": [ + 297, + 125, + 517, + 146 + ], + "type": "text", + "content": "The MetaF2N is trained for one week and all experiments are conducted on a server with one RTX A6000 GPU." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 297, + 154, + 501, + 165 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 154, + 501, + 165 + ], + "spans": [ + { + "bbox": [ + 297, + 154, + 501, + 165 + ], + "type": "text", + "content": "5.2. Comparison with State-of-the-art Methods" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 296, + 170, + 517, + 379 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 170, + 517, + 379 + ], + "spans": [ + { + "bbox": [ + 296, + 170, + 517, + 379 + ], + "type": "text", + "content": "To show the effectiveness of the proposed MetaF2N, we compare with several state-of-the-art blind image SR methods, including ESRGAN [53], RealSR [5], Real-ESRGAN [51], BSRGAN [59], MM-RealSR [39], and RedegNet [26]. For quantitative evaluation, we utilize PSNR, LPIPS [60], FID [17], and NIQE [38] for synthetic datasets. As for the real-world dataset, since no ground-truth is available, PSNR and LPIPS are omitted. It is worth noting that KID is more accurate and appropriate than FID when evaluating the quality of images with a smaller amount of samples [3]. Thus we use KID [3] and NIQE [38] for quantitative evaluation on our RF200 dataset. To accurately calculate the distance between SR results and real-world high-quality images (i.e., FID and KID), we construct these types of reference images following [4], which estimates a blurriness score based on the total variance of the Laplacian of an image. Finally, 3,808 high-quality images are selected from the in-the-wild version of FFHQ [21], whose scores are higher than the threshold defined in [4]." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "spans": [ + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "type": "text", + "content": "Quantitative Comparison. The quantitative evaluation results are provided in Tabs. 1 and 2. We provide three results of our Meta-F2N, i.e., Ours (1), Ours (10), and Ours (20), where the number in the parentheses denotes the amount of fine-tuning steps during inference. All three models are initialized with the same parameter " + }, + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "type": "text", + "content": ". For the degradations independent and identically distributed as the training set (i.e., " + }, + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "type": "inline_equation", + "content": "\\mathrm{FFHQ}_{iid}" + }, + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "type": "text", + "content": " and CelebA" + }, + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "type": "inline_equation", + "content": "_{iid}" + }, + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "type": "text", + "content": "), our MetaF2N can achieve superior performance on LPIPS, FID, and NIQE with only one fine-tuning step, and can surpass most of the competing methods on PSNR. Besides, with more fine-tuning iterations, the image quality can be further enhanced. For out-of-distribution degradations in Tab. 2 (i.e., " + }, + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "type": "inline_equation", + "content": "\\mathrm{FFHQ}_{ood}" + }, + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "type": "text", + "content": ", CelebA" + }, + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "type": "inline_equation", + "content": "_{ood}" + }, + { + "bbox": [ + 296, + 383, + 517, + 557 + ], + "type": "text", + "content": ", and RF200), the trends are similar to Tab. 1, and our MetaF2N again outperforms others on most metrics, especially on the real-world RF200 dataset." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 296, + 558, + 517, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 558, + 517, + 711 + ], + "spans": [ + { + "bbox": [ + 296, + 558, + 517, + 711 + ], + "type": "text", + "content": "As for the competing methods, ESRGAN [53] and RealSR [5] are trained with simple degradation models, which lead to unsatisfactory performance under more complex and realistic degradations. Real-ESRGAN [51], BSRGAN [59], MM-RealSR [39], and ReDegNet [26] leverage more realistic degradation models or even real-world degradations, which contribute to much better results, yet their performance is still limited by the deterministic model and fixed degradation range. Furthermore, we also fine-tune ReDegNet [26] on RF200, and the results are provided in Tab. 2 (ReDegNet†). Compared to MetaF2N that achieves decent performance with only one fine-tuning step, marginal improvements are observed on NIQE even the ReDegNet [26] is carefully fine-tuned hundreds iterations for each image." + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 71, + 700, + 274, + 711 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 700, + 274, + 711 + ], + "spans": [ + { + "bbox": [ + 71, + 700, + 274, + 711 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 71, + 700, + 274, + 711 + ], + "type": "text", + "content": "DF2K is the combination of DIV2K [1] and Flickr2K [46] datasets." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "spans": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "type": "text", + "content": "13038" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 77, + 123, + 137, + 164 + ], + "blocks": [ + { + "bbox": [ + 77, + 123, + 137, + 164 + ], + "lines": [ + { + "bbox": [ + 77, + 123, + 137, + 164 + ], + "spans": [ + { + "bbox": [ + 77, + 123, + 137, + 164 + ], + "type": "image", + "image_path": "c8ca386e0de2c3584d6ca12fed7abdb22a5e99a53e26980e183ae0c122e96194.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 77, + 165, + 137, + 240 + ], + "blocks": [ + { + "bbox": [ + 77, + 165, + 137, + 240 + ], + "lines": [ + { + "bbox": [ + 77, + 165, + 137, + 240 + ], + "spans": [ + { + "bbox": [ + 77, + 165, + 137, + 240 + ], + "type": "image", + "image_path": "f3b31ca2fab7c3471e2a9ad48e47187e1b144eaf6b8d9b5199ff366af8034270.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 77, + 241, + 137, + 286 + ], + "blocks": [ + { + "bbox": [ + 77, + 241, + 137, + 286 + ], + "lines": [ + { + "bbox": [ + 77, + 241, + 137, + 286 + ], + "spans": [ + { + "bbox": [ + 77, + 241, + 137, + 286 + ], + "type": "image", + "image_path": "2d9e97d33919ac8efb54dd80671c9574c4c72b5cc9fcd71c9e60b90d6e94462a.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 86, + 286, + 127, + 294 + ], + "lines": [ + { + "bbox": [ + 86, + 286, + 127, + 294 + ], + "spans": [ + { + "bbox": [ + 86, + 286, + 127, + 294 + ], + "type": "text", + "content": "Synthetic LR" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 138, + 123, + 198, + 164 + ], + "blocks": [ + { + "bbox": [ + 138, + 123, + 198, + 164 + ], + "lines": [ + { + "bbox": [ + 138, + 123, + 198, + 164 + ], + "spans": [ + { + "bbox": [ + 138, + 123, + 198, + 164 + ], + "type": "image", + "image_path": "2bd392cc1e47a22b82973331f50e847117f6f7a80c6735f067eb0c2f85f32df9.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 138, + 165, + 198, + 240 + ], + "blocks": [ + { + "bbox": [ + 138, + 165, + 198, + 240 + ], + "lines": [ + { + "bbox": [ + 138, + 165, + 198, + 240 + ], + "spans": [ + { + "bbox": [ + 138, + 165, + 198, + 240 + ], + "type": "image", + "image_path": "292ea930cf1604bdf0fbb5a971edaddfbfe9096750effb6c8f0544b5b90efa0a.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 138, + 241, + 198, + 286 + ], + "blocks": [ + { + "bbox": [ + 138, + 241, + 198, + 286 + ], + "lines": [ + { + "bbox": [ + 138, + 241, + 198, + 286 + ], + "spans": [ + { + "bbox": [ + 138, + 241, + 198, + 286 + ], + "type": "image", + "image_path": "f1e75c7d0e59e466e7ad140ea5e9c3dc788e8bee02cc885edcc2bfe7d899b600.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 138, + 286, + 198, + 294 + ], + "lines": [ + { + "bbox": [ + 138, + 286, + 198, + 294 + ], + "spans": [ + { + "bbox": [ + 138, + 286, + 198, + 294 + ], + "type": "text", + "content": "Real-ESRGAN [51]" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 198, + 123, + 258, + 164 + ], + "blocks": [ + { + "bbox": [ + 198, + 123, + 258, + 164 + ], + "lines": [ + { + "bbox": [ + 198, + 123, + 258, + 164 + ], + "spans": [ + { + "bbox": [ + 198, + 123, + 258, + 164 + ], + "type": "image", + "image_path": "0c02920714760cde53e52f10961386449a98e208622d08bbf1513c083b2c004b.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 198, + 165, + 258, + 240 + ], + "blocks": [ + { + "bbox": [ + 198, + 165, + 258, + 240 + ], + "lines": [ + { + "bbox": [ + 198, + 165, + 258, + 240 + ], + "spans": [ + { + "bbox": [ + 198, + 165, + 258, + 240 + ], + "type": "image", + "image_path": "e6dc186542afe93de71dde448aaf69b1f4a80ac63a53d1c8d99129103cc58321.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 198, + 241, + 258, + 286 + ], + "blocks": [ + { + "bbox": [ + 198, + 241, + 258, + 286 + ], + "lines": [ + { + "bbox": [ + 198, + 241, + 258, + 286 + ], + "spans": [ + { + "bbox": [ + 198, + 241, + 258, + 286 + ], + "type": "image", + "image_path": "99ba1bdcef4e921812ba41bf73752c5273244211158136940ff7f510c311c448.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 207, + 286, + 251, + 294 + ], + "lines": [ + { + "bbox": [ + 207, + 286, + 251, + 294 + ], + "spans": [ + { + "bbox": [ + 207, + 286, + 251, + 294 + ], + "type": "text", + "content": "BSRGAN [59]" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 259, + 123, + 318, + 164 + ], + "blocks": [ + { + "bbox": [ + 259, + 123, + 318, + 164 + ], + "lines": [ + { + "bbox": [ + 259, + 123, + 318, + 164 + ], + "spans": [ + { + "bbox": [ + 259, + 123, + 318, + 164 + ], + "type": "image", + "image_path": "74d460472d7bf866569be3e53cab3a9c43d14e7e16d1446fb38ea6db3b49df9b.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 259, + 165, + 319, + 240 + ], + "blocks": [ + { + "bbox": [ + 259, + 165, + 319, + 240 + ], + "lines": [ + { + "bbox": [ + 259, + 165, + 319, + 240 + ], + "spans": [ + { + "bbox": [ + 259, + 165, + 319, + 240 + ], + "type": "image", + "image_path": "70d3b07a36f62d2f31f99596c686658cb43f2da55da5e52747478d34651b4455.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 259, + 241, + 319, + 286 + ], + "blocks": [ + { + "bbox": [ + 259, + 241, + 319, + 286 + ], + "lines": [ + { + "bbox": [ + 259, + 241, + 319, + 286 + ], + "spans": [ + { + "bbox": [ + 259, + 241, + 319, + 286 + ], + "type": "image", + "image_path": "0541b81921d249d49026ccb8080bf4198eff49a84b67bbe5b0df49f787e425bb.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 262, + 286, + 315, + 294 + ], + "lines": [ + { + "bbox": [ + 262, + 286, + 315, + 294 + ], + "spans": [ + { + "bbox": [ + 262, + 286, + 315, + 294 + ], + "type": "text", + "content": "MM-RealSR [39]" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 319, + 123, + 379, + 164 + ], + "blocks": [ + { + "bbox": [ + 319, + 123, + 379, + 164 + ], + "lines": [ + { + "bbox": [ + 319, + 123, + 379, + 164 + ], + "spans": [ + { + "bbox": [ + 319, + 123, + 379, + 164 + ], + "type": "image", + "image_path": "abb288e6bda4880caa82cb1774933f7082f0ce575766f9cb6052c58a9341392b.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 319, + 165, + 379, + 240 + ], + "blocks": [ + { + "bbox": [ + 319, + 165, + 379, + 240 + ], + "lines": [ + { + "bbox": [ + 319, + 165, + 379, + 240 + ], + "spans": [ + { + "bbox": [ + 319, + 165, + 379, + 240 + ], + "type": "image", + "image_path": "15021f1bf6a6c95c7c2ac93c12ad1d3e6ea94924f5267e257a8cd93575a30536.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 319, + 241, + 379, + 286 + ], + "blocks": [ + { + "bbox": [ + 319, + 241, + 379, + 286 + ], + "lines": [ + { + "bbox": [ + 319, + 241, + 379, + 286 + ], + "spans": [ + { + "bbox": [ + 319, + 241, + 379, + 286 + ], + "type": "image", + "image_path": "b837f5e322ecc33faf7ea74ef87fe4522141f97100dac29b949ba2d8aa67fccc.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 326, + 286, + 373, + 294 + ], + "lines": [ + { + "bbox": [ + 326, + 286, + 373, + 294 + ], + "spans": [ + { + "bbox": [ + 326, + 286, + 373, + 294 + ], + "type": "text", + "content": "ReDegNet [26]" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 380, + 123, + 440, + 164 + ], + "blocks": [ + { + "bbox": [ + 380, + 123, + 440, + 164 + ], + "lines": [ + { + "bbox": [ + 380, + 123, + 440, + 164 + ], + "spans": [ + { + "bbox": [ + 380, + 123, + 440, + 164 + ], + "type": "image", + "image_path": "29b72e2f104a64ee8702acb7911cac1c4452e02489f014291fd7ae704c5a9bed.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + } + ], + "index": 20 + }, + { + "type": "image", + "bbox": [ + 380, + 165, + 440, + 240 + ], + "blocks": [ + { + "bbox": [ + 380, + 165, + 440, + 240 + ], + "lines": [ + { + "bbox": [ + 380, + 165, + 440, + 240 + ], + "spans": [ + { + "bbox": [ + 380, + 165, + 440, + 240 + ], + "type": "image", + "image_path": "dc81b3f8f3c8b473713d69035fb81c6be0939d527a069e6d7240ad5819e3c1dd.jpg" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_body" + } + ], + "index": 21 + }, + { + "type": "image", + "bbox": [ + 380, + 241, + 440, + 286 + ], + "blocks": [ + { + "bbox": [ + 380, + 241, + 440, + 286 + ], + "lines": [ + { + "bbox": [ + 380, + 241, + 440, + 286 + ], + "spans": [ + { + "bbox": [ + 380, + 241, + 440, + 286 + ], + "type": "image", + "image_path": "984046f723fff7f99e07838ed578a16058eadb2afdc9f7e5d5008264bba39709.jpg" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 402, + 287, + 418, + 294 + ], + "lines": [ + { + "bbox": [ + 402, + 287, + 418, + 294 + ], + "spans": [ + { + "bbox": [ + 402, + 287, + 418, + 294 + ], + "type": "text", + "content": "Ours" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_caption" + } + ], + "index": 22 + }, + { + "type": "image", + "bbox": [ + 440, + 123, + 500, + 164 + ], + "blocks": [ + { + "bbox": [ + 440, + 123, + 500, + 164 + ], + "lines": [ + { + "bbox": [ + 440, + 123, + 500, + 164 + ], + "spans": [ + { + "bbox": [ + 440, + 123, + 500, + 164 + ], + "type": "image", + "image_path": "f21d224c7d56e794af53dceb6ee7449430fb802b184c84631c58b11260d4ebe7.jpg" + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_body" + } + ], + "index": 24 + }, + { + "type": "image", + "bbox": [ + 440, + 165, + 500, + 240 + ], + "blocks": [ + { + "bbox": [ + 440, + 165, + 500, + 240 + ], + "lines": [ + { + "bbox": [ + 440, + 165, + 500, + 240 + ], + "spans": [ + { + "bbox": [ + 440, + 165, + 500, + 240 + ], + "type": "image", + "image_path": "33eade57d93a7503b3bf9362dea39b9b4699c7fdcdece28ff0fc98cdb59485c7.jpg" + } + ] + } + ], + "index": 25, + "angle": 0, + "type": "image_body" + } + ], + "index": 25 + }, + { + "type": "image", + "bbox": [ + 440, + 241, + 500, + 286 + ], + "blocks": [ + { + "bbox": [ + 440, + 241, + 500, + 286 + ], + "lines": [ + { + "bbox": [ + 440, + 241, + 500, + 286 + ], + "spans": [ + { + "bbox": [ + 440, + 241, + 500, + 286 + ], + "type": "image", + "image_path": "db61604dff7829b6f647b07f718ba3be647a77fdc95ec20440157f1ba39e1a60.jpg" + } + ] + } + ], + "index": 26, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 451, + 287, + 490, + 294 + ], + "lines": [ + { + "bbox": [ + 451, + 287, + 490, + 294 + ], + "spans": [ + { + "bbox": [ + 451, + 287, + 490, + 294 + ], + "type": "text", + "content": "Ground-truth" + } + ] + } + ], + "index": 27, + "angle": 0, + "type": "image_caption" + } + ], + "index": 26 + }, + { + "type": "image", + "bbox": [ + 77, + 322, + 137, + 372 + ], + "blocks": [ + { + "bbox": [ + 60, + 295, + 516, + 317 + ], + "lines": [ + { + "bbox": [ + 60, + 295, + 516, + 317 + ], + "spans": [ + { + "bbox": [ + 60, + 295, + 516, + 317 + ], + "type": "text", + "content": "Figure 3: Visual comparison against state-of-the-art blind SR methods on synthetic datasets. Note that the results of Ours are produced by MetaF2N with one-step fine-tuning. Please zoom in for better observation." + } + ] + } + ], + "index": 28, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 77, + 322, + 137, + 372 + ], + "lines": [ + { + "bbox": [ + 77, + 322, + 137, + 372 + ], + "spans": [ + { + "bbox": [ + 77, + 322, + 137, + 372 + ], + "type": "image", + "image_path": "90797db8f37ca3f626263e3467c025a3b6daf24d4c7027243aa172e4a34ee365.jpg" + } + ] + } + ], + "index": 29, + "angle": 0, + "type": "image_body" + } + ], + "index": 29 + }, + { + "type": "image", + "bbox": [ + 77, + 373, + 137, + 431 + ], + "blocks": [ + { + "bbox": [ + 77, + 373, + 137, + 431 + ], + "lines": [ + { + "bbox": [ + 77, + 373, + 137, + 431 + ], + "spans": [ + { + "bbox": [ + 77, + 373, + 137, + 431 + ], + "type": "image", + "image_path": "8477c94867bccef0f2e092a06bc95edd49225d2567fd0b119ad2d5488eda1b83.jpg" + } + ] + } + ], + "index": 30, + "angle": 0, + "type": "image_body" + } + ], + "index": 30 + }, + { + "type": "image", + "bbox": [ + 77, + 431, + 137, + 514 + ], + "blocks": [ + { + "bbox": [ + 77, + 431, + 137, + 514 + ], + "lines": [ + { + "bbox": [ + 77, + 431, + 137, + 514 + ], + "spans": [ + { + "bbox": [ + 77, + 431, + 137, + 514 + ], + "type": "image", + "image_path": "a3a12e5762cf3f501334faf7e58216bcbe1e5fba9bbe0a5e742b6cd231caab11.jpg" + } + ] + } + ], + "index": 31, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 84, + 515, + 130, + 523 + ], + "lines": [ + { + "bbox": [ + 84, + 515, + 130, + 523 + ], + "spans": [ + { + "bbox": [ + 84, + 515, + 130, + 523 + ], + "type": "text", + "content": "Real-world LR" + } + ] + } + ], + "index": 32, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 60, + 525, + 515, + 547 + ], + "lines": [ + { + "bbox": [ + 60, + 525, + 515, + 547 + ], + "spans": [ + { + "bbox": [ + 60, + 525, + 515, + 547 + ], + "type": "text", + "content": "Figure 4: Visual comparison against state-of-the-art blind SR methods on real-world low-quality images in our RF200 dataset. ReDegNet† means that model is fine-tuned for each image following the official configurations of ReDegNet [26]." + } + ] + } + ], + "index": 57, + "angle": 0, + "type": "image_caption" + } + ], + "index": 31 + }, + { + "type": "image", + "bbox": [ + 138, + 322, + 198, + 372 + ], + "blocks": [ + { + "bbox": [ + 138, + 322, + 198, + 372 + ], + "lines": [ + { + "bbox": [ + 138, + 322, + 198, + 372 + ], + "spans": [ + { + "bbox": [ + 138, + 322, + 198, + 372 + ], + "type": "image", + "image_path": "d8ae5eb836c1a586985c8c205d978e5dd1dcc76b382a24c62ca6b99aecf71bc8.jpg" + } + ] + } + ], + "index": 33, + "angle": 0, + "type": "image_body" + } + ], + "index": 33 + }, + { + "type": "image", + "bbox": [ + 138, + 373, + 198, + 431 + ], + "blocks": [ + { + "bbox": [ + 138, + 373, + 198, + 431 + ], + "lines": [ + { + "bbox": [ + 138, + 373, + 198, + 431 + ], + "spans": [ + { + "bbox": [ + 138, + 373, + 198, + 431 + ], + "type": "image", + "image_path": "c22bcdd62f1d5e267cdac7e4b9830f84f84c8318399d8da4075fb88eff8d7bb9.jpg" + } + ] + } + ], + "index": 34, + "angle": 0, + "type": "image_body" + } + ], + "index": 34 + }, + { + "type": "image", + "bbox": [ + 138, + 431, + 198, + 514 + ], + "blocks": [ + { + "bbox": [ + 138, + 431, + 198, + 514 + ], + "lines": [ + { + "bbox": [ + 138, + 431, + 198, + 514 + ], + "spans": [ + { + "bbox": [ + 138, + 431, + 198, + 514 + ], + "type": "image", + "image_path": "1091e6238610d5240f91ff921d3aac814380fef45bb2463a90568c9b5ff0c93e.jpg" + } + ] + } + ], + "index": 35, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 138, + 515, + 198, + 523 + ], + "lines": [ + { + "bbox": [ + 138, + 515, + 198, + 523 + ], + "spans": [ + { + "bbox": [ + 138, + 515, + 198, + 523 + ], + "type": "text", + "content": "Real-ESRGAN [51]" + } + ] + } + ], + "index": 36, + "angle": 0, + "type": "image_caption" + } + ], + "index": 35 + }, + { + "type": "image", + "bbox": [ + 198, + 322, + 258, + 372 + ], + "blocks": [ + { + "bbox": [ + 198, + 322, + 258, + 372 + ], + "lines": [ + { + "bbox": [ + 198, + 322, + 258, + 372 + ], + "spans": [ + { + "bbox": [ + 198, + 322, + 258, + 372 + ], + "type": "image", + "image_path": "29917520a90e722128280dfb2f62f71a86570122f15fbb7f5d80399b9bb91edc.jpg" + } + ] + } + ], + "index": 37, + "angle": 0, + "type": "image_body" + } + ], + "index": 37 + }, + { + "type": "image", + "bbox": [ + 198, + 373, + 258, + 431 + ], + "blocks": [ + { + "bbox": [ + 198, + 373, + 258, + 431 + ], + "lines": [ + { + "bbox": [ + 198, + 373, + 258, + 431 + ], + "spans": [ + { + "bbox": [ + 198, + 373, + 258, + 431 + ], + "type": "image", + "image_path": "f090cb66ca59e509a787d5b78ea8e38d6b8c8345091309f1735ccb4d5e8714d5.jpg" + } + ] + } + ], + "index": 38, + "angle": 0, + "type": "image_body" + } + ], + "index": 38 + }, + { + "type": "image", + "bbox": [ + 198, + 431, + 258, + 514 + ], + "blocks": [ + { + "bbox": [ + 198, + 431, + 258, + 514 + ], + "lines": [ + { + "bbox": [ + 198, + 431, + 258, + 514 + ], + "spans": [ + { + "bbox": [ + 198, + 431, + 258, + 514 + ], + "type": "image", + "image_path": "bd396fc02925daaa1bf24073e85323d895aa360e1a3204094127a9eecbf93f6a.jpg" + } + ] + } + ], + "index": 39, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 207, + 515, + 251, + 523 + ], + "lines": [ + { + "bbox": [ + 207, + 515, + 251, + 523 + ], + "spans": [ + { + "bbox": [ + 207, + 515, + 251, + 523 + ], + "type": "text", + "content": "BSRGAN [59]" + } + ] + } + ], + "index": 40, + "angle": 0, + "type": "image_caption" + } + ], + "index": 39 + }, + { + "type": "image", + "bbox": [ + 259, + 322, + 318, + 372 + ], + "blocks": [ + { + "bbox": [ + 259, + 322, + 318, + 372 + ], + "lines": [ + { + "bbox": [ + 259, + 322, + 318, + 372 + ], + "spans": [ + { + "bbox": [ + 259, + 322, + 318, + 372 + ], + "type": "image", + "image_path": "48a60a266aa0fb4ec000bb1d0b7380d1fa2aa70779e06f8e87762b7dab5bb45a.jpg" + } + ] + } + ], + "index": 41, + "angle": 0, + "type": "image_body" + } + ], + "index": 41 + }, + { + "type": "image", + "bbox": [ + 259, + 373, + 319, + 431 + ], + "blocks": [ + { + "bbox": [ + 259, + 373, + 319, + 431 + ], + "lines": [ + { + "bbox": [ + 259, + 373, + 319, + 431 + ], + "spans": [ + { + "bbox": [ + 259, + 373, + 319, + 431 + ], + "type": "image", + "image_path": "1fec9269dc52275437abfd001bcace5e3a5142b5673311195a67d3bd11dbd92f.jpg" + } + ] + } + ], + "index": 42, + "angle": 0, + "type": "image_body" + } + ], + "index": 42 + }, + { + "type": "image", + "bbox": [ + 259, + 431, + 319, + 514 + ], + "blocks": [ + { + "bbox": [ + 259, + 431, + 319, + 514 + ], + "lines": [ + { + "bbox": [ + 259, + 431, + 319, + 514 + ], + "spans": [ + { + "bbox": [ + 259, + 431, + 319, + 514 + ], + "type": "image", + "image_path": "dc200565769a18bb3bc6c3436f274ae9a4c3fbdaddd46d6c1929258f9d164c20.jpg" + } + ] + } + ], + "index": 43, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 262, + 515, + 315, + 523 + ], + "lines": [ + { + "bbox": [ + 262, + 515, + 315, + 523 + ], + "spans": [ + { + "bbox": [ + 262, + 515, + 315, + 523 + ], + "type": "text", + "content": "MM-RealSR [39]" + } + ] + } + ], + "index": 44, + "angle": 0, + "type": "image_caption" + } + ], + "index": 43 + }, + { + "type": "image", + "bbox": [ + 319, + 322, + 379, + 372 + ], + "blocks": [ + { + "bbox": [ + 319, + 322, + 379, + 372 + ], + "lines": [ + { + "bbox": [ + 319, + 322, + 379, + 372 + ], + "spans": [ + { + "bbox": [ + 319, + 322, + 379, + 372 + ], + "type": "image", + "image_path": "a1a4554caed9fb7c9177b1eb295a29a852856fb04428acf3723be79ba89ae773.jpg" + } + ] + } + ], + "index": 45, + "angle": 0, + "type": "image_body" + } + ], + "index": 45 + }, + { + "type": "image", + "bbox": [ + 319, + 373, + 379, + 431 + ], + "blocks": [ + { + "bbox": [ + 319, + 373, + 379, + 431 + ], + "lines": [ + { + "bbox": [ + 319, + 373, + 379, + 431 + ], + "spans": [ + { + "bbox": [ + 319, + 373, + 379, + 431 + ], + "type": "image", + "image_path": "68e8ab179dfa3fe19d8c7a877a2652150cc019b89928efaf5cce42433e3302d2.jpg" + } + ] + } + ], + "index": 46, + "angle": 0, + "type": "image_body" + } + ], + "index": 46 + }, + { + "type": "image", + "bbox": [ + 319, + 431, + 379, + 514 + ], + "blocks": [ + { + "bbox": [ + 319, + 431, + 379, + 514 + ], + "lines": [ + { + "bbox": [ + 319, + 431, + 379, + 514 + ], + "spans": [ + { + "bbox": [ + 319, + 431, + 379, + 514 + ], + "type": "image", + "image_path": "b9eafe7835425c64b34aa7655334e57538466b56badae1db2ca7b8eeefb50a45.jpg" + } + ] + } + ], + "index": 47, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 326, + 515, + 373, + 523 + ], + "lines": [ + { + "bbox": [ + 326, + 515, + 373, + 523 + ], + "spans": [ + { + "bbox": [ + 326, + 515, + 373, + 523 + ], + "type": "text", + "content": "ReDegNet [26]" + } + ] + } + ], + "index": 48, + "angle": 0, + "type": "image_caption" + } + ], + "index": 47 + }, + { + "type": "image", + "bbox": [ + 380, + 322, + 440, + 372 + ], + "blocks": [ + { + "bbox": [ + 380, + 322, + 440, + 372 + ], + "lines": [ + { + "bbox": [ + 380, + 322, + 440, + 372 + ], + "spans": [ + { + "bbox": [ + 380, + 322, + 440, + 372 + ], + "type": "image", + "image_path": "8fe645a0101fc0c3cb776d937913870ab102bb3052df6f9d34f9b79f8bb53f6c.jpg" + } + ] + } + ], + "index": 49, + "angle": 0, + "type": "image_body" + } + ], + "index": 49 + }, + { + "type": "image", + "bbox": [ + 380, + 373, + 440, + 431 + ], + "blocks": [ + { + "bbox": [ + 380, + 373, + 440, + 431 + ], + "lines": [ + { + "bbox": [ + 380, + 373, + 440, + 431 + ], + "spans": [ + { + "bbox": [ + 380, + 373, + 440, + 431 + ], + "type": "image", + "image_path": "a6f9d6da8d1977ee9caf0f43ffa941159927cbb3933052f7ba235d6382d52ee0.jpg" + } + ] + } + ], + "index": 50, + "angle": 0, + "type": "image_body" + } + ], + "index": 50 + }, + { + "type": "image", + "bbox": [ + 380, + 431, + 440, + 514 + ], + "blocks": [ + { + "bbox": [ + 380, + 431, + 440, + 514 + ], + "lines": [ + { + "bbox": [ + 380, + 431, + 440, + 514 + ], + "spans": [ + { + "bbox": [ + 380, + 431, + 440, + 514 + ], + "type": "image", + "image_path": "67566032ef532b513c75c788940df48b7da70161d2283de9677eb48ec3f6bf3d.jpg" + } + ] + } + ], + "index": 51, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 385, + 515, + 434, + 523 + ], + "lines": [ + { + "bbox": [ + 385, + 515, + 434, + 523 + ], + "spans": [ + { + "bbox": [ + 385, + 515, + 434, + 523 + ], + "type": "text", + "content": "ReDegNet [26]" + } + ] + } + ], + "index": 52, + "angle": 0, + "type": "image_caption" + } + ], + "index": 51 + }, + { + "type": "image", + "bbox": [ + 440, + 322, + 500, + 372 + ], + "blocks": [ + { + "bbox": [ + 440, + 322, + 500, + 372 + ], + "lines": [ + { + "bbox": [ + 440, + 322, + 500, + 372 + ], + "spans": [ + { + "bbox": [ + 440, + 322, + 500, + 372 + ], + "type": "image", + "image_path": "08faeaf42b6832cd8a3a0e2783482caadddb568d696121cb1d342d7f0f86551d.jpg" + } + ] + } + ], + "index": 53, + "angle": 0, + "type": "image_body" + } + ], + "index": 53 + }, + { + "type": "image", + "bbox": [ + 440, + 373, + 500, + 431 + ], + "blocks": [ + { + "bbox": [ + 440, + 373, + 500, + 431 + ], + "lines": [ + { + "bbox": [ + 440, + 373, + 500, + 431 + ], + "spans": [ + { + "bbox": [ + 440, + 373, + 500, + 431 + ], + "type": "image", + "image_path": "1d0872bcbeb1cd4a6bdfcc69f175d8f45376aee4121df3f9304f864d0419c765.jpg" + } + ] + } + ], + "index": 54, + "angle": 0, + "type": "image_body" + } + ], + "index": 54 + }, + { + "type": "image", + "bbox": [ + 440, + 431, + 500, + 514 + ], + "blocks": [ + { + "bbox": [ + 440, + 431, + 500, + 514 + ], + "lines": [ + { + "bbox": [ + 440, + 431, + 500, + 514 + ], + "spans": [ + { + "bbox": [ + 440, + 431, + 500, + 514 + ], + "type": "image", + "image_path": "3709756ab95397b548fd4a3ec2724dca4b10000d6a5322fda6e7d223126e26ab.jpg" + } + ] + } + ], + "index": 55, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 463, + 515, + 478, + 523 + ], + "lines": [ + { + "bbox": [ + 463, + 515, + 478, + 523 + ], + "spans": [ + { + "bbox": [ + 463, + 515, + 478, + 523 + ], + "type": "text", + "content": "Ours" + } + ] + } + ], + "index": 56, + "angle": 0, + "type": "image_caption" + } + ], + "index": 55 + }, + { + "bbox": [ + 60, + 557, + 281, + 666 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 557, + 281, + 666 + ], + "spans": [ + { + "bbox": [ + 60, + 557, + 281, + 666 + ], + "type": "text", + "content": "Qualitative Comparison. Apart from the quantitative comparison, we also compare our MetaF2N with state-of-the-art blind image SR methods qualitatively. Due to the space limit, we show the results generated by Ours (1), which is fine-tuned for 1 step with the face regions, and more qualitative results (including those generated by Ours (10) and Ours (20)) are provided in the supplementary material. As shown in Figs. 3 and 4, our results are much clearer and contain more photo-realistic textures, which can be ascribed to the effectiveness of our image-specific fine-tuning scheme." + } + ] + } + ], + "index": 58 + }, + { + "bbox": [ + 61, + 672, + 214, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 672, + 214, + 682 + ], + "spans": [ + { + "bbox": [ + 61, + 672, + 214, + 682 + ], + "type": "text", + "content": "5.3. The Visual Results of MaskNet" + } + ] + } + ], + "index": 59 + }, + { + "bbox": [ + 60, + 688, + 280, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 688, + 280, + 711 + ], + "spans": [ + { + "bbox": [ + 60, + 688, + 280, + 711 + ], + "type": "text", + "content": "To better explain the effect of our MaskNet, we calculate the error map " + }, + { + "bbox": [ + 60, + 688, + 280, + 711 + ], + "type": "inline_equation", + "content": "EM" + }, + { + "bbox": [ + 60, + 688, + 280, + 711 + ], + "type": "text", + "content": " between ground-truth faces " + }, + { + "bbox": [ + 60, + 688, + 280, + 711 + ], + "type": "inline_equation", + "content": "\\mathbf{I}^{\\odot}" + }, + { + "bbox": [ + 60, + 688, + 280, + 711 + ], + "type": "text", + "content": " and" + } + ] + } + ], + "index": 60 + }, + { + "bbox": [ + 297, + 557, + 516, + 579 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 557, + 516, + 579 + ], + "spans": [ + { + "bbox": [ + 297, + 557, + 516, + 579 + ], + "type": "text", + "content": "GPEN [57] generated faces " + }, + { + "bbox": [ + 297, + 557, + 516, + 579 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{BFR}^{\\odot}" + }, + { + "bbox": [ + 297, + 557, + 516, + 579 + ], + "type": "text", + "content": " directly through subtraction and normalization, i.e.," + } + ] + } + ], + "index": 61 + }, + { + "bbox": [ + 354, + 583, + 516, + 609 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 354, + 583, + 516, + 609 + ], + "spans": [ + { + "bbox": [ + 354, + 583, + 516, + 609 + ], + "type": "interline_equation", + "content": "E M = \\frac {\\left| \\mathbf {I} ^ {\\ominus} - \\mathbf {I} _ {B F R} ^ {\\ominus} \\right|}{\\operatorname* {m a x} \\left(\\left| \\mathbf {I} ^ {\\ominus} - \\mathbf {I} _ {B F R} ^ {\\ominus} \\right|\\right)}. \\tag {14}", + "image_path": "5277a9ac0689853bddfb46f37e950b60face63914e158735737677f7710e0240.jpg" + } + ] + } + ], + "index": 62 + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "spans": [ + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "content": "In Fig. 5, we show the predicted " + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "inline_equation", + "content": "\\mathbf{m}" + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "inline_equation", + "content": "1 - EM" + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "content": ". One can see that the predicted " + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "inline_equation", + "content": "\\mathbf{m}" + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "content": " follows similar distribution to " + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "inline_equation", + "content": "1 - EM" + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "content": ", indicating that our MaskNet has the ability to predict the gap between generated faces and real ones, which benefits the blind image SR performance. Besides, the predicted " + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "inline_equation", + "content": "\\mathbf{m}" + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "content": " is smoother than " + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "inline_equation", + "content": "1 - EM" + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "content": ", due to that 1) " + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "inline_equation", + "content": "\\mathbf{m}" + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "content": " is predicted from " + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "inline_equation", + "content": "(\\mathbf{I}_{LR}^{\\ominus}" + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_{BFR}^{\\ominus})" + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "content": ", which lead to less accurate results, and 2) a regularization term " + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{\\mathrm{reg}} = \\| \\mathbf{m} - 1\\|_2" + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "content": " is applied to constrain " + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "inline_equation", + "content": "\\mathbf{m}" + }, + { + "bbox": [ + 296, + 612, + 517, + 711 + ], + "type": "text", + "content": " not to deviate too far from 1." + } + ] + } + ], + "index": 63 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "spans": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "type": "text", + "content": "13039" + } + ] + } + ], + "index": 64 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 82, + 173, + 493, + 293 + ], + "blocks": [ + { + "bbox": [ + 60, + 127, + 518, + 171 + ], + "lines": [ + { + "bbox": [ + 60, + 127, + 518, + 171 + ], + "spans": [ + { + "bbox": [ + 60, + 127, + 518, + 171 + ], + "type": "text", + "content": "Table 1: Quantitative comparison on synthetic datasets with independent and identically distributed degradations as the training set. We also show the datasets used for training each method. Note that RealFaces used by ReDegNet [26] consists of 10,000 real-world low-quality face images collected by the authors. The numbers in the parentheses are the image-specific fine-tuning steps of our MetaF2N during inference. The best and second-best results are highlighted by bold and underline." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 82, + 173, + 493, + 293 + ], + "lines": [ + { + "bbox": [ + 82, + 173, + 493, + 293 + ], + "spans": [ + { + "bbox": [ + 82, + 173, + 493, + 293 + ], + "type": "table", + "html": "
MethodsTraining SetFFHQiiidCelebAiid
PSNR↑LPIPS↓FID↓NIQE↓PSNR↑LPIPS↓FID↓NIQE↓
ESRGAN [53]DF2K [1,46], OST [52]25.100.642123.677.5624.780.55599.106.27
RealSR [19]DF2K [1,46]25.390.597122.237.5924.740.54999.465.77
Real-ESRGAN [51]DF2K [1,46], OST [52]26.350.29350.704.8525.810.31151.695.00
BSRGAN [59]DF2K [1,46], FFFHQ [21], WED [35]26.270.30550.984.6325.860.30950.054.83
MM-RealSR [39]DF2K [1,46], OST [52]25.390.29550.834.5824.940.31152.304.76
ReDegNet [26]DF2K [1,46], FFFHQ [21], RealFaces25.640.30957.044.7925.170.32956.844.94
Ours (1)DF2K [1,46], FFFHQ [21]26.130.28144.943.8125.630.28945.723.97
Ours (10)DF2K [1,46], FFFHQ [21]26.220.28044.943.8725.700.28945.434.03
Ours (20)DF2K [1,46], FFFHQ [21]26.300.27944.513.9425.760.28945.224.10
", + "image_path": "18880d4c2e7aef0eb52d8027194ec333c21ec2c9496c78678aa30dc59ced71da.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "table", + "bbox": [ + 119, + 347, + 458, + 478 + ], + "blocks": [ + { + "bbox": [ + 60, + 302, + 518, + 346 + ], + "lines": [ + { + "bbox": [ + 60, + 302, + 518, + 346 + ], + "spans": [ + { + "bbox": [ + 60, + 302, + 518, + 346 + ], + "type": "text", + "content": "Table 2: Quantitative comparison on synthetic datasets with out-of-distribution degradations and the collected real-world dataset RF200. ReDegNet† means that model is fine-tuned for each image following the official configurations of ReDeg-Net [26]. The numbers in the parentheses are the image-specific fine-tuning steps of our MetaF2N during inference. The best and second-best results are highlighted by bold and underline." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 119, + 347, + 458, + 478 + ], + "lines": [ + { + "bbox": [ + 119, + 347, + 458, + 478 + ], + "spans": [ + { + "bbox": [ + 119, + 347, + 458, + 478 + ], + "type": "table", + "html": "
MethodsFFHQoodCelebAoodRF200
PSNR↑LPIPS↓FID↓NIQE↓PSNR↑LPIPS↓FID↓NIQE↓KID↓NIQE↓
ESRGAN [53]24.690.659101.436.9424.070.56787.615.6421.85.32
RealSR [19]24.910.58797.426.3323.980.56790.305.5121.95.00
Real-ESRGAN [51]25.730.30247.875.3425.070.32248.775.4322.43.82
BSRGAN [59]25.730.29846.404.7825.330.31348.124.9122.14.11
MM-RealSR [39]25.030.29747.304.9924.410.31748.765.1022.14.12
ReDegNet [26]25.540.30448.475.0924.760.33152.335.2823.54.07
ReDegNet†[26]--------23.83.56
Ours (1)25.490.28445.074.2224.870.29747.034.3221.23.03
Ours (10)25.570.28444.644.3024.930.29746.504.3921.03.08
Ours (20)25.650.28344.304.3625.000.29746.234.4720.83.12
", + "image_path": "70c2646c244837b0950266fbaead4c00f933c1812b87ef9e337d25770e59fd16.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_body" + } + ], + "index": 3 + }, + { + "bbox": [ + 61, + 492, + 152, + 504 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 61, + 492, + 152, + 504 + ], + "spans": [ + { + "bbox": [ + 61, + 492, + 152, + 504 + ], + "type": "text", + "content": "5.4. Ablation Studies" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 60, + 509, + 280, + 575 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 509, + 280, + 575 + ], + "spans": [ + { + "bbox": [ + 60, + 509, + 280, + 575 + ], + "type": "text", + "content": "To verify the effectiveness of the components of the proposed MetaF2N, we have also conducted several ablation studies. Without loss of generality, all ablation studies are performed with " + }, + { + "bbox": [ + 60, + 509, + 280, + 575 + ], + "type": "inline_equation", + "content": "\\mathrm{FFHQ}_{i id}" + }, + { + "bbox": [ + 60, + 509, + 280, + 575 + ], + "type": "text", + "content": " based on Ours (1). Due to the space limit, qualitative results of ablation studies are given in the supplementary material." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 60, + 579, + 282, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 579, + 282, + 711 + ], + "spans": [ + { + "bbox": [ + 60, + 579, + 282, + 711 + ], + "type": "text", + "content": "MaskNet Configuration. To show the effectiveness of the MaskNet, we train a variant of our MetaF2N by removing the MaskNet. Besides, as introduced in Sec. 1, we design the MaskNet inspired by degraded-reference IQA methods, which takes both low-quality and restored faces as input (denoted by " + }, + { + "bbox": [ + 60, + 579, + 282, + 711 + ], + "type": "inline_equation", + "content": "\\mathrm{MaskNet}_{DR}" + }, + { + "bbox": [ + 60, + 579, + 282, + 711 + ], + "type": "text", + "content": "). For verifying the design, we also consider another variant of MetaF2N which utilizes the non-reference scheme, i.e., only the restored face is taken by the MaskNet (denoted by " + }, + { + "bbox": [ + 60, + 579, + 282, + 711 + ], + "type": "inline_equation", + "content": "\\mathrm{MaskNet}_{NR}" + }, + { + "bbox": [ + 60, + 579, + 282, + 711 + ], + "type": "text", + "content": "). As shown in Tab. 3, the deployment of MaskNet brings considerable improvements, and utilizing the low-quality face image as a reference is also useful for our task." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 296, + 492, + 517, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 492, + 517, + 604 + ], + "spans": [ + { + "bbox": [ + 296, + 492, + 517, + 604 + ], + "type": "text", + "content": "Training Data Configuration. Since ground-truth faces are available during training, we train another variant by using the ground-truth face image as the inner loop supervision. Note that the MaskNet is trained together with the SR model, and we omitted it when training the version using ground-truth faces as inner loop supervision since the optimal solution should be an all-one mask. As shown in Tab. 3, the performance decreases by a large margin compared to MetaF2N, which is attributed to the gaps in the inner loop supervision between the training and inference phases." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 296, + 607, + 518, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 607, + 518, + 696 + ], + "spans": [ + { + "bbox": [ + 296, + 607, + 518, + 696 + ], + "type": "text", + "content": "Inner Loop Supervision Scheme. Since there are often multiple faces in a single image, as a natural extension of our method, it is intuitive to apply multiple faces to stabilize the fine-tuning process. Therefore, we also explore the inner loop supervision scheme based on another 1,000 images sampled from the in-the-wild version of FFHQ [21] with multiple faces. As shown in Tab. 4, using patches of multiple faces can slightly benefit the final performance." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 298, + 700, + 518, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 700, + 518, + 711 + ], + "spans": [ + { + "bbox": [ + 298, + 700, + 518, + 711 + ], + "type": "text", + "content": "Influence of Different Face Hallucination Network. To" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "spans": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "type": "text", + "content": "13040" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 69, + 122, + 273, + 445 + ], + "blocks": [ + { + "bbox": [ + 69, + 122, + 273, + 445 + ], + "lines": [ + { + "bbox": [ + 69, + 122, + 273, + 445 + ], + "spans": [ + { + "bbox": [ + 69, + 122, + 273, + 445 + ], + "type": "image", + "image_path": "5547abbf98f572c9575eed8c353976212af4198d644908cbd849dcf27353b6cb.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 102, + 446, + 238, + 457 + ], + "lines": [ + { + "bbox": [ + 102, + 446, + 238, + 457 + ], + "spans": [ + { + "bbox": [ + 102, + 446, + 238, + 457 + ], + "type": "text", + "content": "Figure 5: Visual results of MaskNet." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 60, + 464, + 281, + 585 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 464, + 281, + 585 + ], + "spans": [ + { + "bbox": [ + 60, + 464, + 281, + 585 + ], + "type": "text", + "content": "find the influence of different face hallucination network for the MetaF2N, we conduct an ablation study by replacing GPEN [57] with CodeFormer [63] during training and testing. As shown in Tab. 5, one can see that our MetaF2N shows satisfactory robustness with different face hallucination networks for both " + }, + { + "bbox": [ + 60, + 464, + 281, + 585 + ], + "type": "inline_equation", + "content": "\\mathrm{FFHQ}_{i\\bar{i}d}" + }, + { + "bbox": [ + 60, + 464, + 281, + 585 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 60, + 464, + 281, + 585 + ], + "type": "inline_equation", + "content": "\\mathrm{FFHQ}_{\\mathrm{ood}}" + }, + { + "bbox": [ + 60, + 464, + 281, + 585 + ], + "type": "text", + "content": ". Although the CodeFormer [63] can restore higher quality faces compared with GPEN [57], our MaskNet minish the gap through allocating weights for each pixel of restored faces, which enhances the robustness of MetaF2N for different face hallucination networks." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 60, + 596, + 280, + 641 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 60, + 596, + 280, + 641 + ], + "spans": [ + { + "bbox": [ + 60, + 596, + 280, + 641 + ], + "type": "text", + "content": "Table 3: Ablation study on the training scheme regarding data configuration and the MaskNet. Train/Test Faces denote the setting of inner-loop supervision during the training and inference stages." + } + ] + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 64, + 643, + 278, + 706 + ], + "blocks": [ + { + "bbox": [ + 64, + 643, + 278, + 706 + ], + "lines": [ + { + "bbox": [ + 64, + 643, + 278, + 706 + ], + "spans": [ + { + "bbox": [ + 64, + 643, + 278, + 706 + ], + "type": "table", + "html": "
MaskNetTrain FacesTest FacesPSNR↑LPIPS↓FID↓NIQE↓
-GTGPEN25.680.28546.964.08
-GPENGPEN26.170.28447.894.21
MaskNetNRGPENGPEN26.070.28447.974.09
MaskNetDRGPENGPEN26.130.28145.223.81
", + "image_path": "521cc3022f4f2c5fb71764b8d96cb4fbfbb9fbee73895a27d741ec7289ddd06c.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "type": "table", + "bbox": [ + 302, + 161, + 511, + 228 + ], + "blocks": [ + { + "bbox": [ + 297, + 127, + 517, + 159 + ], + "lines": [ + { + "bbox": [ + 297, + 127, + 517, + 159 + ], + "spans": [ + { + "bbox": [ + 297, + 127, + 517, + 159 + ], + "type": "text", + "content": "Table 4: Ablation study on inner loop supervision, which is performed on 1,000 images with multiple faces (" + }, + { + "bbox": [ + 297, + 127, + 517, + 159 + ], + "type": "inline_equation", + "content": "\\sim" + }, + { + "bbox": [ + 297, + 127, + 517, + 159 + ], + "type": "text", + "content": "2.3 faces/image) from the in-the-wild version of FFHQ [21]." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 302, + 161, + 511, + 228 + ], + "lines": [ + { + "bbox": [ + 302, + 161, + 511, + 228 + ], + "spans": [ + { + "bbox": [ + 302, + 161, + 511, + 228 + ], + "type": "table", + "html": "
# of FacesData FormPSNR↑LPIPS↓FID↓NIQE↓
SingleFull image25.730.28842.963.63
Single32 patches25.770.28842.893.65
Multiple32 patches in total25.790.28742.853.65
Multiple32 patches per face25.790.28742.813.65
", + "image_path": "e2e376dfb6d52377b020b6fe06f5bbf02d48277a6c7e565b40206ebfac50ad64.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 300, + 259, + 517, + 328 + ], + "blocks": [ + { + "bbox": [ + 297, + 235, + 516, + 258 + ], + "lines": [ + { + "bbox": [ + 297, + 235, + 516, + 258 + ], + "spans": [ + { + "bbox": [ + 297, + 235, + 516, + 258 + ], + "type": "text", + "content": "Table 5: Ablation study on face hallucination networks which is performed on both " + }, + { + "bbox": [ + 297, + 235, + 516, + 258 + ], + "type": "inline_equation", + "content": "\\mathrm{FFHQ}_{iid}" + }, + { + "bbox": [ + 297, + 235, + 516, + 258 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 297, + 235, + 516, + 258 + ], + "type": "inline_equation", + "content": "\\mathrm{FFHQ}_{ood}" + }, + { + "bbox": [ + 297, + 235, + 516, + 258 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 300, + 259, + 517, + 328 + ], + "lines": [ + { + "bbox": [ + 300, + 259, + 517, + 328 + ], + "spans": [ + { + "bbox": [ + 300, + 259, + 517, + 328 + ], + "type": "table", + "html": "
TestsetsTrain FacesTest FacesPSNR↑LPIPS↓FID↓NIQE↓
FFHQidGPENGPEN26.130.28145.223.81
CodeFormerCodeFormer26.100.27845.833.83
FFHQoodGPENGPEN25.490.28445.074.22
CodeFormerCodeFormer25.510.28144.584.24
", + "image_path": "1b02c90001273f05c9b394878c716b11c859c103ae6f964d1e9a2d384dc822df.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "bbox": [ + 297, + 346, + 445, + 358 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 346, + 445, + 358 + ], + "spans": [ + { + "bbox": [ + 297, + 346, + 445, + 358 + ], + "type": "text", + "content": "5.5. Limitations and Future Work" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 296, + 365, + 517, + 476 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 365, + 517, + 476 + ], + "spans": [ + { + "bbox": [ + 296, + 365, + 517, + 476 + ], + "type": "text", + "content": "Since our MetaF2N is trained in a MAML framework, the performance before fine-tuning is unconstrained. As such, our model requires fine-tuning with the contained faces for one or multiple steps, making it cannot be directly applied if no faces exist in real-world low-quality images, which limits the application scenarios of our method. In the future, we plan to solve this problem by collecting a real-world low-quality training set and providing a better initialization of parameters that can be used to achieve satisfactory performance even without fine-tuning." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 297, + 490, + 363, + 502 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 297, + 490, + 363, + 502 + ], + "spans": [ + { + "bbox": [ + 297, + 490, + 363, + 502 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 296, + 511, + 517, + 631 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 511, + 517, + 631 + ], + "spans": [ + { + "bbox": [ + 296, + 511, + 517, + 631 + ], + "type": "text", + "content": "In this paper, we proposed a MetaF2N framework for face-guided blind image SR. The MetaF2N improves the practicability of leveraging blind face restoration for processing image-specific degradations. A MaskNet is deployed to predict the loss weights for different positions considering the gaps between recovered faces and potential ground-truth ones. The proposed MetaF2N achieves superior performance on synthetic datasets with both independent and identically distributed and out-of-distribution degradations compared to training sets. The effectiveness is also validated on the collected real-world dataset." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 298, + 646, + 387, + 660 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 298, + 646, + 387, + 660 + ], + "spans": [ + { + "bbox": [ + 298, + 646, + 387, + 660 + ], + "type": "text", + "content": "Acknowledgement" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 296, + 666, + 517, + 711 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 666, + 517, + 711 + ], + "spans": [ + { + "bbox": [ + 296, + 666, + 517, + 711 + ], + "type": "text", + "content": "This work was supported in part by the National Key Research and Development Program of China under Grant No. 2022YFA1004103 and the National Natural Science Foundation of China (NSFC) under Grant No. U19A2073." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "spans": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "type": "text", + "content": "13041" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 62, + 123, + 115, + 135 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 123, + 115, + 135 + ], + "spans": [ + { + "bbox": [ + 62, + 123, + 115, + 135 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 63, + 142, + 280, + 709 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 66, + 142, + 280, + 182 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 142, + 280, + 182 + ], + "spans": [ + { + "bbox": [ + 66, + 142, + 280, + 182 + ], + "type": "text", + "content": "[1] Eirikur Agustsson and Radu Timofte. NTIRE 2017 challenge on single image super-resolution: Dataset and study. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 126-135, 2017. 6, 8" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 66, + 183, + 280, + 213 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 183, + 280, + 213 + ], + "spans": [ + { + "bbox": [ + 66, + 183, + 280, + 213 + ], + "type": "text", + "content": "[2] Shahrukh Athar and Zhou Wang. Degraded reference image quality assessment. IEEE Transactions on Image Processing, pages 822-837, 2023. 2, 4" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 66, + 214, + 280, + 252 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 214, + 280, + 252 + ], + "spans": [ + { + "bbox": [ + 66, + 214, + 280, + 252 + ], + "type": "text", + "content": "[3] Mikołaj Binkowski, Danica J Sutherland, Michael Arbel, and Arthur Gretton. Demystifying mmd gans. In International Conference on Learning Representations, pages 1-36, 2018. 6" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 66, + 254, + 280, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 254, + 280, + 274 + ], + "spans": [ + { + "bbox": [ + 66, + 254, + 280, + 274 + ], + "type": "text", + "content": "[4] Will Brennan. BlurDetection2. https://github.com/WillBrennan/BlurDetection2, 2017.6" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 66, + 275, + 280, + 324 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 275, + 280, + 324 + ], + "spans": [ + { + "bbox": [ + 66, + 275, + 280, + 324 + ], + "type": "text", + "content": "[5] Jianrui Cai, Hui Zeng, Hongwei Yong, Zisheng Cao, and Lei Zhang. Toward real-world single image super-resolution: A new benchmark and a new model. In IEEE International Conference on Computer Vision, pages 3086-3095, 2019. 1, 2, 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 66, + 325, + 280, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 325, + 280, + 374 + ], + "spans": [ + { + "bbox": [ + 66, + 325, + 280, + 374 + ], + "type": "text", + "content": "[6] Kelvin CK Chan, Xintao Wang, Xiangyu Xu, Jinwei Gu, and Chen Change Loy. GLEAN: Generative latent bank for large-factor image super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 14245-14254, 2021. 3, 4" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 66, + 376, + 280, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 376, + 280, + 426 + ], + "spans": [ + { + "bbox": [ + 66, + 376, + 280, + 426 + ], + "type": "text", + "content": "[7] Chaofeng Chen, Xiaoming Li, Lingbo Yang, Xianhui Lin, Lei Zhang, and Kwan-Yee K Wong. Progressive semantic-aware style transformation for blind face restoration. In IEEE Conference on Computer Vision and Pattern Recognition, pages 11896-11905, 2021. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 66, + 427, + 280, + 466 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 427, + 280, + 466 + ], + "spans": [ + { + "bbox": [ + 66, + 427, + 280, + 466 + ], + "type": "text", + "content": "[8] Chang Chen, Zhiwei Xiong, Xinmei Tian, Zheng-Jun Zha, and Feng Wu. Camera lens super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 1652-1660, 2019. 1, 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 66, + 468, + 280, + 507 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 468, + 280, + 507 + ], + "spans": [ + { + "bbox": [ + 66, + 468, + 280, + 507 + ], + "type": "text", + "content": "[9] Honggang Chen, Xiaohai He, Linbo Qing, Yuanyuan Wu, Chao Ren, Ray E Sheriff, and Ce Zhu. Real-world single image super-resolution: A brief review. Information Fusion, pages 124-145, 2022. 1, 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 63, + 508, + 280, + 548 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 508, + 280, + 548 + ], + "spans": [ + { + "bbox": [ + 63, + 508, + 280, + 548 + ], + "type": "text", + "content": "[10] Mohammad Emad, Maurice Peemen, and Henk Corporaal. DualSR: Zero-shot dual learning for real-world superresolution. In IEEE Winter Conference on Applications of Computer Vision, pages 1630-1639, 2021. 1" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 63, + 549, + 280, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 549, + 280, + 588 + ], + "spans": [ + { + "bbox": [ + 63, + 549, + 280, + 588 + ], + "type": "text", + "content": "[11] Chelsea Finn, Pieter Abbeel, and Sergey Levine. Model-agnostic meta-learning for fast adaptation of deep networks. In International Conference on Machine Learning, pages 1126–1135, 2017. 2, 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 63, + 589, + 280, + 628 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 589, + 280, + 628 + ], + "spans": [ + { + "bbox": [ + 63, + 589, + 280, + 628 + ], + "type": "text", + "content": "[12] Manuel Fritsche, Shuhang Gu, and Radu Timofte. Frequency separation for real-world super-resolution. In IEEE International Conference on Computer Vision Workshops, pages 3599-3608, 2019. 2" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 63, + 629, + 280, + 670 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 629, + 280, + 670 + ], + "spans": [ + { + "bbox": [ + 63, + 629, + 280, + 670 + ], + "type": "text", + "content": "[13] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial networks. Communications of the ACM, pages 139–144, 2020. 5" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 63, + 671, + 280, + 709 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 671, + 280, + 709 + ], + "spans": [ + { + "bbox": [ + 63, + 671, + 280, + 709 + ], + "type": "text", + "content": "[14] Erin Grant, Chelsea Finn, Sergey Levine, Trevor Darrell, and Thomas Griffiths. Recasting gradient-based meta-learning as hierarchical bayes. arXiv preprint arXiv:1801.08930, 2018. 3" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 299, + 126, + 517, + 711 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 299, + 126, + 517, + 165 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 126, + 517, + 165 + ], + "spans": [ + { + "bbox": [ + 299, + 126, + 517, + 165 + ], + "type": "text", + "content": "[15] Jinjin Gu, Hannan Lu, Wangmeng Zuo, and Chao Dong. Blind super-resolution with iterative kernel correction. In IEEE Conference on Computer Vision and Pattern Recognition, pages 1604-1613, 2019. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 299, + 166, + 517, + 216 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 166, + 517, + 216 + ], + "spans": [ + { + "bbox": [ + 299, + 166, + 517, + 216 + ], + "type": "text", + "content": "[16] Yuchao Gu, Xintao Wang, Liangbin Xie, Chao Dong, Gen Li, Ying Shan, and Ming-Ming Cheng. VQFR: Blind face restoration with vector-quantized dictionary and parallel decoder. In European Conference on Computer Vision, pages 126–143, 2022. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 299, + 217, + 517, + 266 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 217, + 517, + 266 + ], + "spans": [ + { + "bbox": [ + 299, + 217, + 517, + 266 + ], + "type": "text", + "content": "[17] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in Neural Information Processing Systems, pages 6626-6637, 2017. 6" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 299, + 267, + 516, + 307 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 267, + 516, + 307 + ], + "spans": [ + { + "bbox": [ + 299, + 267, + 516, + 307 + ], + "type": "text", + "content": "[18] Yan Huang, Shang Li, Liang Wang, Tieniu Tan, et al. Unfolding the alternating optimization for blind super resolution. Advances in Neural Information Processing Systems, pages 5632-5643, 2020. 2" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 299, + 307, + 516, + 357 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 307, + 516, + 357 + ], + "spans": [ + { + "bbox": [ + 299, + 307, + 516, + 357 + ], + "type": "text", + "content": "[19] Xiaozhong Ji, Yun Cao, Ying Tai, Chengjie Wang, Jilin Li, and Feiyue Huang. Real-world super-resolution via kernel estimation and noise injection. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 466-467, 2020. 2, 8" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 299, + 357, + 516, + 417 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 357, + 516, + 417 + ], + "spans": [ + { + "bbox": [ + 299, + 357, + 516, + 417 + ], + "type": "text", + "content": "[20] Hamid Reza Vaezi Joze, Ilya Zharkov, Karlton Powell, Carl Ringler, Luming Liang, Andy Roulston, Moshe Lutz, and Vivek Pradeep. ImagePairs: Realistic super resolution dataset via beam splitter camera rig. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 518-519, 2020. 2" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 299, + 418, + 516, + 458 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 418, + 516, + 458 + ], + "spans": [ + { + "bbox": [ + 299, + 418, + 516, + 458 + ], + "type": "text", + "content": "[21] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In IEEE Conference on Computer Vision and Pattern Recognition, pages 4401-4410, 2019. 2, 6, 8, 9" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 299, + 458, + 516, + 508 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 458, + 516, + 508 + ], + "spans": [ + { + "bbox": [ + 299, + 458, + 516, + 508 + ], + "type": "text", + "content": "[22] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of stylegan. In IEEE Conference on Computer Vision and Pattern Recognition, pages 8110-8119, 2020. 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 299, + 509, + 516, + 538 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 509, + 516, + 538 + ], + "spans": [ + { + "bbox": [ + 299, + 509, + 516, + 538 + ], + "type": "text", + "content": "[23] Diederik P Kingma and Jimmy Ba. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980, 2014. 6" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 299, + 538, + 516, + 578 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 538, + 516, + 578 + ], + "spans": [ + { + "bbox": [ + 299, + 538, + 516, + 578 + ], + "type": "text", + "content": "[24] Alex Krizhevsky, Ilya Sutskever, and Geoffrey E Hinton. Imagenet classification with deep convolutional neural networks. Communications of the ACM, pages 84-90, 2017. 5" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 299, + 579, + 516, + 619 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 579, + 516, + 619 + ], + "spans": [ + { + "bbox": [ + 299, + 579, + 516, + 619 + ], + "type": "text", + "content": "[25] Royson Lee, Rui Li, Stylianos I Venieris, Timothy Hospedales, Ferenc Huszár, and Nicholas D Lane. Metalearned kernel for blind super-resolution kernel estimation. arXiv preprint arXiv:2212.07886, 2022. 3, 5" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 299, + 620, + 516, + 670 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 620, + 516, + 670 + ], + "spans": [ + { + "bbox": [ + 299, + 620, + 516, + 670 + ], + "type": "text", + "content": "[26] Xiaoming Li, Chaofeng Chen, Xianhui Lin, Wangmeng Zuo, and Lei Zhang. From face to natural image: Learning real degradation for blind image super-resolution. In European Conference on Computer Vision, pages 376-392, 2022. 1, 3, 4, 6, 7, 8" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 299, + 671, + 516, + 711 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 671, + 516, + 711 + ], + "spans": [ + { + "bbox": [ + 299, + 671, + 516, + 711 + ], + "type": "text", + "content": "[27] Xiaoming Li, Chaofeng Chen, Shangchen Zhou, Xianhui Lin, Wangmeng Zuo, and Lei Zhang. Blind face restoration via deep multi-scale component dictionaries. In European Conference on Computer Vision, pages 399-415, 2020. 3" + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "spans": [ + { + "bbox": [ + 277, + 737, + 301, + 746 + ], + "type": "text", + "content": "13042" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 62, + 125, + 281, + 711 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 62, + 125, + 281, + 176 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 125, + 281, + 176 + ], + "spans": [ + { + "bbox": [ + 62, + 125, + 281, + 176 + ], + "type": "text", + "content": "[28] Xiaoming Li, Wenyu Li, Dongwei Ren, Hongzhi Zhang, Meng Wang, and Wangmeng Zuo. Enhanced blind face restoration with multi-exemplar images and adaptive spatial feature fusion. In IEEE Conference on Computer Vision and Pattern Recognition, pages 2706-2715, 2020. 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 62, + 177, + 280, + 218 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 177, + 280, + 218 + ], + "spans": [ + { + "bbox": [ + 62, + 177, + 280, + 218 + ], + "type": "text", + "content": "[29] Xiaoming Li, Ming Liu, Yuting Ye, Wangmeng Zuo, Liang Lin, and Ruigang Yang. Learning warped guidance for blind face restoration. In European Conference on Computer Vision, pages 272-289, 2018. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 63, + 218, + 280, + 258 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 218, + 280, + 258 + ], + "spans": [ + { + "bbox": [ + 63, + 218, + 280, + 258 + ], + "type": "text", + "content": "[30] Xiaoming Li, Shiguang Zhang, Shangchen Zhou, Lei Zhang, and Wangmeng Zuo. Learning dual memory dictionaries for blind face restoration. IEEE Transactions on Pattern Analysis and Machine Intelligence, pages 1-13, 2022. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 63, + 259, + 280, + 300 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 259, + 280, + 300 + ], + "spans": [ + { + "bbox": [ + 63, + 259, + 280, + 300 + ], + "type": "text", + "content": "[31] Xiaoming Li, Wangmeng Zuo, and Chen Change Loy. Learning generative structure prior for blind text image super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 10103-10113, 2023. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 63, + 301, + 280, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 301, + 280, + 330 + ], + "spans": [ + { + "bbox": [ + 63, + 301, + 280, + 330 + ], + "type": "text", + "content": "[32] Weixin Liang, Zixuan Liu, and Can Liu. Dawson: A domain adaptive few shot generation framework. arXiv preprint arXiv:2001.00576, 2020. 5" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 63, + 332, + 280, + 372 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 332, + 280, + 372 + ], + "spans": [ + { + "bbox": [ + 63, + 332, + 280, + 372 + ], + "type": "text", + "content": "[33] Anran Liu, Yihao Liu, Jinjin Gu, Yu Qiao, and Chao Dong. Blind image super-resolution: A survey and beyond. IEEE Transactions on Pattern Analysis and Machine Intelligence, pages 1-19, 2022. 1, 2" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 63, + 373, + 280, + 412 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 373, + 280, + 412 + ], + "spans": [ + { + "bbox": [ + 63, + 373, + 280, + 412 + ], + "type": "text", + "content": "[34] Ziwei Liu, Ping Luo, Xiaogang Wang, and Xiaou Tang. Deep learning face attributes in the wild. In IEEE International Conference on Computer Vision, pages 3730-3738, 2015. 2, 6" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 63, + 414, + 280, + 463 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 414, + 280, + 463 + ], + "spans": [ + { + "bbox": [ + 63, + 414, + 280, + 463 + ], + "type": "text", + "content": "[35] Kede Ma, Zhengfang Duanmu, Qingbo Wu, Zhou Wang, Hongwei Yong, Hongliang Li, and Lei Zhang. Waterloo exploration database: New challenges for image quality assessment models. IEEE Transactions on Image Processing, pages 1004-1016, 2016. 8" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 63, + 464, + 280, + 515 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 464, + 280, + 515 + ], + "spans": [ + { + "bbox": [ + 63, + 464, + 280, + 515 + ], + "type": "text", + "content": "[36] Sachit Menon, Alexandru Damian, Shijia Hu, Nikhil Ravi, and Cynthia Rudin. PULSE: Self-supervised photo upsampling via latent space exploration of generative models. In IEEE Conference on Computer Vision and Pattern Recognition, pages 2437-2445, 2020. 1" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 63, + 516, + 280, + 547 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 516, + 280, + 547 + ], + "spans": [ + { + "bbox": [ + 63, + 516, + 280, + 547 + ], + "type": "text", + "content": "[37] Nikhil Mishra, Mostafa Rohaninejad, Xi Chen, and Pieter Abbeel. A simple neural attentive meta-learner. arXiv preprint arXiv:1707.03141, 2017. 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 63, + 548, + 280, + 577 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 548, + 280, + 577 + ], + "spans": [ + { + "bbox": [ + 63, + 548, + 280, + 577 + ], + "type": "text", + "content": "[38] Anish Mittal, Rajiv Soundararajan, and Alan C Bovik. Making a \"completely blind\" image quality analyzer. IEEE Signal Processing Letters, pages 209-212, 2012. 6" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 63, + 579, + 280, + 628 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 579, + 280, + 628 + ], + "spans": [ + { + "bbox": [ + 63, + 579, + 280, + 628 + ], + "type": "text", + "content": "[39] Chong Mou, Yanze Wu, Xintao Wang, Chao Dong, Jian Zhang, and Ying Shan. Metric learning based interactive modulation for real-world super-resolution. In European Conference on Computer Vision, pages 723-740, 2022. 6, 7, 8" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 63, + 629, + 280, + 670 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 629, + 280, + 670 + ], + "spans": [ + { + "bbox": [ + 63, + 629, + 280, + 670 + ], + "type": "text", + "content": "[40] Boris Oreshkin, Pau Rodríguez López, and Alexandre Lacoste. TADAM: Task dependent adaptive metric for improved few-shot learning. Advances in Neural Information Processing Systems, pages 719-729, 2018. 3" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 63, + 671, + 280, + 711 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 671, + 280, + 711 + ], + "spans": [ + { + "bbox": [ + 63, + 671, + 280, + 711 + ], + "type": "text", + "content": "[41] Seobin Park, Jinsu Yoo, Donghyeon Cho, Jiwon Kim, and Tae Hyun Kim. Fast adaptation to super-resolution networks via meta-learning. In European Conference on Computer Vision, pages 754-769, 2020. 3, 4" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 299, + 126, + 517, + 711 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 299, + 126, + 517, + 165 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 126, + 517, + 165 + ], + "spans": [ + { + "bbox": [ + 299, + 126, + 517, + 165 + ], + "type": "text", + "content": "[42] Assaf Shocher, Nadav Cohen, and Michal Irani. \"zero-shot\" super-resolution using deep internal learning. In IEEE Conference on Computer Vision and Pattern Recognition, pages 3118-3126, 2018. 1, 2" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 299, + 168, + 517, + 207 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 168, + 517, + 207 + ], + "spans": [ + { + "bbox": [ + 299, + 168, + 517, + 207 + ], + "type": "text", + "content": "[43] Jae Woong Soh, Sunwoo Cho, and Nam Ik Cho. Meta-transfer learning for zero-shot super-resolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 3516-3525, 2020. 3, 4" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 299, + 209, + 516, + 248 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 209, + 516, + 248 + ], + "spans": [ + { + "bbox": [ + 299, + 209, + 516, + 248 + ], + "type": "text", + "content": "[44] Qianru Sun, Yaoyao Liu, Tat-Seng Chua, and Bernt Schiele. Meta-transfer learning for few-shot learning. In IEEE Conference on Computer Vision and Pattern Recognition, pages 403-412, 2019. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 299, + 250, + 516, + 299 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 250, + 516, + 299 + ], + "spans": [ + { + "bbox": [ + 299, + 250, + 516, + 299 + ], + "type": "text", + "content": "[45] Flood Sung, Yongxin Yang, Li Zhang, Tao Xiang, Philip HS Torr, and Timothy M Hospedales. Learning to compare: Relation network for few-shot learning. In IEEE Conference on Computer Vision and Pattern Recognition, pages 1199-1208, 2018. 3" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 299, + 301, + 516, + 351 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 301, + 516, + 351 + ], + "spans": [ + { + "bbox": [ + 299, + 301, + 516, + 351 + ], + "type": "text", + "content": "[46] Radu Timofte, Eirikur Agustsson, Luc Van Gool, Ming-Hsuan Yang, and Lei Zhang. NTIRE 2017 challenge on single image super-resolution: Methods and results. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 114-125, 2017. 6, 8" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 299, + 352, + 516, + 383 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 352, + 516, + 383 + ], + "spans": [ + { + "bbox": [ + 299, + 352, + 516, + 383 + ], + "type": "text", + "content": "[47] Dmitry Ulyanov, Andrea Vedaldi, and Victor Lempitsky. Deep image prior. In IEEE Conference on Computer Vision and Pattern Recognition, pages 9446-9454, 2018. 1, 2" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 299, + 383, + 516, + 423 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 383, + 516, + 423 + ], + "spans": [ + { + "bbox": [ + 299, + 383, + 516, + 423 + ], + "type": "text", + "content": "[48] Oriol Vinyals, Charles Blundell, Timothy Lillicrap, Daan Wierstra, et al. Matching networks for one shot learning. Advances in Neural Information Processing Systems, pages 3630-3638, 2016. 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 299, + 425, + 516, + 474 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 425, + 516, + 474 + ], + "spans": [ + { + "bbox": [ + 299, + 425, + 516, + 474 + ], + "type": "text", + "content": "[49] Longguang Wang, Yingqian Wang, Xiaoyu Dong, Qingyu Xu, Jungang Yang, Wei An, and Yulan Guo. Unsupervised degradation representation learning for blind superresolution. In IEEE Conference on Computer Vision and Pattern Recognition, pages 10581-10590, 2021. 2" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 299, + 475, + 516, + 516 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 475, + 516, + 516 + ], + "spans": [ + { + "bbox": [ + 299, + 475, + 516, + 516 + ], + "type": "text", + "content": "[50] Xintao Wang, Yu Li, Honglun Zhang, and Ying Shan. Towards real-world blind face restoration with generative facial prior. In IEEE Conference on Computer Vision and Pattern Recognition, pages 9168-9178, 2021. 1, 3, 4" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 299, + 516, + 516, + 557 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 516, + 516, + 557 + ], + "spans": [ + { + "bbox": [ + 299, + 516, + 516, + 557 + ], + "type": "text", + "content": "[51] Xintao Wang, Liangbin Xie, Chao Dong, and Ying Shan. Real-ESRGAN: Training real-world blind super-resolution with pure synthetic data. In IEEE International Conference on Computer Vision, pages 1905–1914, 2021. 1, 2, 5, 6, 7, 8" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 299, + 558, + 516, + 607 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 558, + 516, + 607 + ], + "spans": [ + { + "bbox": [ + 299, + 558, + 516, + 607 + ], + "type": "text", + "content": "[52] Xintao Wang, Ke Yu, Chao Dong, and Chen Change Loy. Recovering realistic texture in image super-resolution by deep spatial feature transform. In IEEE Conference on Computer Vision and Pattern Recognition, pages 606-615, 2018. 8" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 299, + 609, + 516, + 658 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 609, + 516, + 658 + ], + "spans": [ + { + "bbox": [ + 299, + 609, + 516, + 658 + ], + "type": "text", + "content": "[53] Xintao Wang, Ke Yu, Shixiang Wu, Jinjin Gu, Yihao Liu, Chao Dong, Yu Qiao, and Chen Change Loy. ESRGAN: Enhanced super-resolution generative adversarial networks. In European Conference on Computer Vision Workshops, pages 63-79, 2018. 2, 4, 6, 8" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 299, + 660, + 516, + 711 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 299, + 660, + 516, + 711 + ], + "spans": [ + { + "bbox": [ + 299, + 660, + 516, + 711 + ], + "type": "text", + "content": "[54] Zhouxia Wang, Jiawei Zhang, Runjian Chen, Wenping Wang, and Ping Luo. RestoreFormer: High-quality blind face restoration from undegraded key-value pairs. In IEEE Conference on Computer Vision and Pattern Recognition, pages 17491-17500, 2022. 3" + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "spans": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "type": "text", + "content": "13043" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 10 + }, + { + "para_blocks": [ + { + "bbox": [ + 62, + 125, + 280, + 585 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 62, + 125, + 280, + 175 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 125, + 280, + 175 + ], + "spans": [ + { + "bbox": [ + 62, + 125, + 280, + 175 + ], + "type": "text", + "content": "[55] Pengxu Wei, Ziwei Xie, Hannan Lu, Zongyuan Zhan, Qixiang Ye, Wangmeng Zuo, and Liang Lin. Component divide-and-conquer for real-world image super-resolution. In European Conference on Computer Vision, pages 101-117, 2020. 1, 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 62, + 177, + 280, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 177, + 280, + 217 + ], + "spans": [ + { + "bbox": [ + 62, + 177, + 280, + 217 + ], + "type": "text", + "content": "[56] Shuo Yang, Ping Luo, Chen Change Loy, and Xiaou Tang. Wider face: A face detection benchmark. In IEEE Conference on Computer Vision and Pattern Recognition, pages 5525-5533, 2016. 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 63, + 218, + 280, + 258 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 218, + 280, + 258 + ], + "spans": [ + { + "bbox": [ + 63, + 218, + 280, + 258 + ], + "type": "text", + "content": "[57] Tao Yang, Peiran Ren, Xuansong Xie, and Lei Zhang. Gan prior embedded network for blind face restoration in the wild. In IEEE Conference on Computer Vision and Pattern Recognition, pages 672-681, 2021. 1, 3, 4, 5, 7, 9" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 63, + 260, + 280, + 309 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 260, + 280, + 309 + ], + "spans": [ + { + "bbox": [ + 63, + 260, + 280, + 309 + ], + "type": "text", + "content": "[58] Yuan Yuan, Siyuan Liu, Jiawei Zhang, Yongbing Zhang, Chao Dong, and Liang Lin. Unsupervised image superresolution using cycle-in-cycle generative adversarial networks. In IEEE Conference on Computer Vision and Pattern Recognition Workshops, pages 701-710, 2018. 2" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 63, + 310, + 280, + 350 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 310, + 280, + 350 + ], + "spans": [ + { + "bbox": [ + 63, + 310, + 280, + 350 + ], + "type": "text", + "content": "[59] Kai Zhang, Jingyun Liang, Luc Van Gool, and Radu Timofte. Designing a practical degradation model for deep blind image super-resolution. In IEEE International Conference on Computer Vision, pages 4791-4800, 2021. 1, 2, 6, 7, 8" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 63, + 351, + 280, + 399 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 351, + 280, + 399 + ], + "spans": [ + { + "bbox": [ + 63, + 351, + 280, + 399 + ], + "type": "text", + "content": "[60] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In IEEE Conference on Computer Vision and Pattern Recognition, pages 586-595, 2018. 5, 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 63, + 402, + 280, + 441 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 402, + 280, + 441 + ], + "spans": [ + { + "bbox": [ + 63, + 402, + 280, + 441 + ], + "type": "text", + "content": "[61] Xuaner Zhang, Qifeng Chen, Ren Ng, and Vladlen Koltun. Zoom to learn, learn to zoom. In IEEE Conference on Computer Vision and Pattern Recognition, pages 3762-3770, 2019. 1" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 63, + 443, + 280, + 492 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 443, + 280, + 492 + ], + "spans": [ + { + "bbox": [ + 63, + 443, + 280, + 492 + ], + "type": "text", + "content": "[62] Heliang Zheng, Huan Yang, Jianlong Fu, Zheng-Jun Zha, and Jiebo Luo. Learning conditional knowledge distillation for degraded-reference image quality assessment. In IEEE International Conference on Computer Vision, pages 10242-10251, 2021. 2, 4" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 63, + 495, + 280, + 532 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 495, + 280, + 532 + ], + "spans": [ + { + "bbox": [ + 63, + 495, + 280, + 532 + ], + "type": "text", + "content": "[63] Shangchen Zhou, Kelvin CK Chan, Chongyi Li, and Chen Change Loy. Towards robust blind face restoration with codebook lookup transformer. arXiv preprint arXiv:2206.11253, 2022. 1, 3, 9" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 63, + 535, + 280, + 585 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 63, + 535, + 280, + 585 + ], + "spans": [ + { + "bbox": [ + 63, + 535, + 280, + 585 + ], + "type": "text", + "content": "[64] Feida Zhu, Junwei Zhu, Wenqing Chu, Xinyi Zhang, Xiaozhong Ji, Chengjie Wang, and Ying Tai. Blind face restoration via integrating face shape and generative priors. In IEEE Conference on Computer Vision and Pattern Recognition, pages 7662-7671, 2022. 3, 4" + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "spans": [ + { + "bbox": [ + 277, + 737, + 300, + 746 + ], + "type": "text", + "content": "13044" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 595, + 842 + ], + "page_idx": 11 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/991c02f6-2cc1-4391-a19c-b8559690aace_content_list.json b/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/991c02f6-2cc1-4391-a19c-b8559690aace_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..b0c4977bf8ab9ee02a1238b4887305a393c4514e --- /dev/null +++ b/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/991c02f6-2cc1-4391-a19c-b8559690aace_content_list.json @@ -0,0 +1,1435 @@ +[ + { + "type": "text", + "text": "MetaGCD: Learning to Continually Learn in Generalized Category Discovery", + "text_level": 1, + "bbox": [ + 91, + 130, + 879, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Yanan Wu $^{1,2*}$ , Zhixiang Chi $^{3*}$ , Yang Wang $^{4}$ , Songhe Feng $^{1,2\\dagger}$", + "bbox": [ + 264, + 179, + 740, + 198 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1Key Laboratory of Big Data & Artificial Intelligence in Transportation, Ministry of Education, Beijing Jiaotong University, Beijing, 100044, China", + "bbox": [ + 212, + 198, + 797, + 233 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{2}$ School of Computer and Information Technology, Beijing Jiaotong University, Beijing, 100044, China \n $^{3}$ Department of Electrical and Computer Engineering, University of Toronto, Toronto, M5G1V7, Canada \n $^{4}$ Department of Computer Science and Software Engineering, Concordia University, Montreal, H3G2J1, Canada", + "bbox": [ + 91, + 233, + 911, + 304 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{ynwu0510,shfeng}@bjtu.edu.cn,zhixiang.chi@mail.utoronto.ca,yang.wang@concordia.ca", + "bbox": [ + 135, + 306, + 861, + 321 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 356, + 312, + 372 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In this paper, we consider a real-world scenario where a model that is trained on pre-defined classes continually encounters unlabeled data that contains both known and novel classes. The goal is to continually discover novel classes while maintaining the performance in known classes. We name the setting Continual Generalized Category Discovery (C-GCD). Existing methods for novel class discovery cannot directly handle the C-GCD setting due to some unrealistic assumptions, such as the unlabeled data only containing novel classes. Furthermore, they fail to discover novel classes in a continual fashion. In this work, we lift all these assumptions and propose an approach, called MetaGCD, to learn how to incrementally discover with less forgetting. Our proposed method uses a meta-learning framework and leverages the offline labeled data to simulate the testing incremental learning process. A meta-objective is defined to revolve around two conflicting learning objectives to achieve novel class discovery without forgetting. Furthermore, a soft neighborhood-based contrastive network is proposed to discriminate uncorrelated images while attracting correlated images. We build strong baselines and conduct extensive experiments on three widely used benchmarks to demonstrate the superiority of our method.", + "bbox": [ + 75, + 388, + 473, + 734 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 763, + 207, + 780 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Object categories in real-world environments are dynamically evolving and expanding over time. However, conventional deep learning-based visual recognition methods normally focus on closed-world scenarios with pre-defined categories [19, 37]. Such systems are brittle when deployed to", + "bbox": [ + 75, + 789, + 468, + 866 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/077eab0066f1e2e63bd1cb6c52b242d4b07a55a192300dd264147b6651586117.jpg", + "image_caption": [ + "Figure 1: Illustration of our C-GCD setting. During the offline training, we learn an initial model based on training samples of the labeled set. During each subsequent online incremental learning, we are given some unlabeled images belonging to both known and novel classes. Our goal is to update the model in each incremental session so that the model can maintain the performance on old classes while discovering novel classes." + ], + "image_footnote": [], + "bbox": [ + 506, + 354, + 888, + 570 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "an ever-changing realistic open-world setting, where object instances may come from new categories. In contrast, recognizing the known categories and utilizing them to discern the unknowns are intrinsic to human perception.", + "bbox": [ + 496, + 732, + 892, + 792 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Recently, discovering the novel classes among unlabeled data has been an active area of research [15, 11, 40, 35, 45]. However, most prior works make several assumptions that are unrealistic in practice. For example, the works in [15, 11, 40] assume the co-existence of both labeled data (with known classes) and unlabeled data (contains potential unknown classes to be discovered) at the training phase and", + "bbox": [ + 496, + 795, + 893, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*The authors contributed equally to this work.", + "bbox": [ + 94, + 875, + 339, + 887 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "† Corresponding Author", + "bbox": [ + 96, + 887, + 223, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "1655", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "the models are learned from scratch. This leads to repetitive large-scale training every time when new classes are expected to be discovered. The works in [15, 11, 35, 45] assume the newly encountered unlabeled data only belongs to the novel classes. This is unrealistic in practice. To meet such conditions, a rigorous filtering method is needed to precisely filter out known class data to avoid degenerate solutions. Due to these limitations, none of these works can be used to build recognition systems that can deal with evolving object categories sequentially over a long time horizon.", + "bbox": [ + 75, + 90, + 472, + 243 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this paper, we consider a more flexible setting for real-world applications. Let us consider the application of home robots. The robots are equipped with an offline trained object recognition model on pre-defined categories during manufacturing. After deployment, the robots are expected to operate in diverse environments. While operating, they continually receive data that belongs to known and possibly unknown classes. Ideally, we would like the robots to continually discover and learn novel classes from such data. We dub such a setting as Continuous Generalized Class Discovery (C-GCD). As shown in Fig. 1, C-GCD has two phases: 1) an offline training phase that allows the model to be trained on large-scale labeled data with pre-defined classes; 2) when the model is deployed, it continually encounters unlabeled data that comes from both known and novel classes on a longer horizon. At each incremental session, the data from the previous sessions is inaccessible. The model needs to precisely classify the known classes and discover novel ones to expand its knowledge base. Obviously, the main challenge of C-GCD is to discover the novel classes among unlabeled images that contain both known and unknown categories while maintaining the performance on old classes. However, learning novel knowledge normally leads to notorious catastrophic forgetting [7], which further exacerbates the model performance.", + "bbox": [ + 75, + 246, + 472, + 625 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "There are some initial attempts on C-GCD [21, 45]. However, they only consider C-GCD at the deployment stage mentioned above. The offline training stage is not fully exploited in these works. Concretely, the labeled data during offline training is only used for pre-training model representations. Therefore, the model at the offline stage is unaware of its subsequent learning duty (discover novel classes and retain the performance of known classes) [8] and is also prone to overfit to the labeled set [40]. Such learning objective misalignment leads to cumbersome heuristic strategies to facilitate the new learning task while keeping the previous knowledge. For example, to learn the novel classes, [21] requires a self-labeling method, which may cause error propagation. A routing strategy is also required to determine the known and novel classifier heads. [45] relies on a thresholding method to filter novel instances. However, the overall robustness of the method can be sensitive to the threshold. To alleviate the", + "bbox": [ + 75, + 628, + 472, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "forgetting issues, [21, 45] propose to distill the knowledge from the pre-trained base models. Data replay is also utilized to either directly select representative labeled exemplars [45] or generate pseudo-latent representations from them [21]. Consequently, the base models and the replay buffers have to be stored locally which may cause storage problems, especially in a resource-constraint environment.", + "bbox": [ + 496, + 90, + 890, + 196 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this work, we propose a fully learning-based solution, named MetaGCD, to minimize the hand-engineered heuristics in prior works. Concretely, at the offline training phase, instead of pre-training a model representation, we directly train an initialization that is learned to discover novel categories with less forgetting when deployed. It is realized by meta-learning-based bi-level optimization [12] to couple the offline training and downstream learning objectives. During the offline training, we simulate the testing scenario and construct pseudo incremental novel class discovery sessions using the labeled data. At each incremental session, we discover novel classes by updating the model using an unsupervised contrastive loss. The meta-objective is then defined by validating the updated model on all classes encountered on a labeled pseudo test set. Therefore, the meta-objective of the offline training is aligned with the evaluation protocol at deployment. It enforces the model to learn to balance two conflicting objectives, namely discovering new objects and not-forgetting old objects. The meta-objective also reinforces the unsupervised updated model to be supervised by the true labels to ensure valid novel class discovery.", + "bbox": [ + 496, + 198, + 892, + 513 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "MetaGCD uses unsupervised contrastive learning to explore the relationship among instances for novel class discovery. Therefore, it is less prone to label overfitting [40]. However, we observe that the negative pairs in contrastive learning normally dominate the loss function. So we further propose soft neighborhood contrastive learning to mine more positiveness. Concretely, for each image instance, we select the nearest candidate neighbors within the batch to treat them as soft positive samples to contribute to the discriminative feature learning. Overall, our contributions are summarised as follows:", + "bbox": [ + 496, + 513, + 893, + 679 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We consider a realistic setting C-GCD for applications in real-world scenarios. It allows the model trained on pre-defined classes to continually explore novel classes through incoming unlabeled data while simultaneously keeping the performance of known classes.", + "- We propose a meta-learning approach where the learning objective is well aligned with the evaluation protocol during testing. It directly optimizes the model to achieve novel object discovery without forgetting.", + "- A soft neighborhood contrastive learning method is also proposed to mine more soft positive pairs to elevate the discovery capability.", + "- We establish strong baselines and show that our method achieves superior performance with less hand" + ], + "bbox": [ + 517, + 688, + 890, + 901 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "1656", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "engineered design through extensive experiments.", + "bbox": [ + 109, + 90, + 439, + 107 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 76, + 119, + 218, + 135 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Discovering novel classes. Novel Class Discovery (NCD) aims to discover the novel classes from unlabeled data by utilizing the prior knowledge from the labeled data [15, 11, 17]. However, NCD assumes that the unlabeled data only belongs to the novel classes, which is unrealistic. Alternatively, a generalized version of NCD (GCD) [40] relaxes such constrain. Although GCD allows the unlabeled data to contain both known and novel classes, they are both required to be present in the training phase. It leads to repetitive large-scale training when different groups of unlabeled data are continually presented to the recognition system. Recently, a class incremental variant of NCD (class-iNCD) is proposed to learn the tasks of labeled known and unlabeled novel classes sequentially [35]. When learning the novel classes, the data of old classes are inaccessible. In the end, the model is evaluated on all encountered classes. Nevertheless, only a few incremental sessions containing unlabeled novel classes are allowed in class-iNCD. This limitation hinders its applicability under the realistic setting with continually evolved object categories. Our proposed C-GCD alleviates the above limitations in real-world scenarios. Our approach can learn from labeled pre-defined classes during offline training, and then continuously encounter unlabeled data with both known and novel classes after deployment. Our model will learn to discover novel classes without forgetting old classes. C-GCD is also related to the classic class-incremental setting [26, 41, 31, 29]. But C-GCD is more challenging as the newly evolved classes are unlabeled and an automatic class discovery mechanism is required [21].", + "bbox": [ + 76, + 145, + 472, + 598 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Meta-learning. Existing meta-learning methods can be categorized into: 1) model-based [36, 2, 4]; 2) Optimization-based [34, 12, 5]; and 3) metric-based [38]. Typical meta-learning methods utilize bi-level optimization to train a model that is applicable for downstream adaptations. Our work is built upon MAML [12], which trains a model initialization through episodes of tasks for fast adaptation via gradient updates. Such learning paradigm has been widely applied in different vision tasks, such as test-time adaptation [39, 28, 32, 30], continual learning [43, 20, 42] and domain shift [44, 46, 13]. In our case, the adaptation is achieved in an unsupervised manner, and the bi-level optimization is utilized to combine two conflicting learning objectives: discovering the novel classes without forgetting the old classes.", + "bbox": [ + 76, + 598, + 472, + 824 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Contrastive learning. Contrastive learning has been popular in self-supervised visual representation learning [1, 6, 18, 33, 27]. It explores the relationships among data instances by constructing positive and negative pairs. Therefore, the overfitting on the label space is reduced to im", + "bbox": [ + 76, + 824, + 472, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "prove the generalization of downstream tasks. Zhong et al. [47] apply contrastive learning to discover novel classes by exploring the data neighborhood and choosing pseudopositive pairs. However, those pseudo-positive pairs contribute equally regardless of their closeness compared to the reference sample. In this work, we introduce the soft positiveness concept to allow adaptive contribution.", + "bbox": [ + 496, + 90, + 893, + 198 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. The Proposed Method", + "text_level": 1, + "bbox": [ + 498, + 209, + 710, + 226 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Problem definition. The goal of C-GCD is to have the offline trained model continually discover and learn novel object classes from unlabeled data containing both known and novel classes. We define a sequence of $T$ learning sessions $\\{S^0, S^1, \\dots, S^T\\}$ . Let $x^t \\in \\mathcal{X}^t$ and $y^t \\in \\mathcal{Y}^t$ denote the input and label space at session $t$ . We represent each session as: $S^0 = \\{(\\mathbf{x}_i^0, \\mathbf{y}_i^0)\\}_{i=1}^{Z_0}$ and $S^t = \\{(\\mathbf{x}_i^t)\\}_{i=1}^{Z_t}$ . Note, only the first session (i.e., $t = 0$ ) contains large-scale labeled samples. As for $t > 0$ , $S^t$ only contains unlabeled data. At the $t^{th}$ session, only $S^t$ is accessible, and the incoming data belongs to both learned known class from previous sessions and novel classes. Therefore, we can denote $\\mathcal{Y}^t = \\mathcal{Y}^{t-1} \\cup \\mathcal{Y}_n^t$ , where $\\mathcal{Y}_n^t$ represents the novel classes to be discovered at session $t$ . After learning on $S^t$ , the model is evaluated on all test images accumulated until session $t$ to test the performance on $\\mathcal{Y}^{t-1}$ (ideally the model should not forget old classes) and the discovery capability on $\\mathcal{Y}_n^t$ . Compared with previous works [15, 11, 35, 45], C-GCD is much more challenging due to several factors. First, the unlabeled data contains both known and unknown classes, i.e., $\\mathcal{Y}^t = \\mathcal{Y}^{t-1} \\cup \\mathcal{Y}_n^t$ . Second, labeled data is absent at $t > 0$ , i.e., $S^0 \\cup S^t = \\emptyset$ where $t > 0$ . Finally, since C-GCD operates on a long horizon, i.e., $t \\gg 1$ , the catastrophic forgetting issue is more severe.", + "bbox": [ + 496, + 234, + 893, + 595 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Method overview. Fig. 2 shows an overview of MetaGCD. Following [40], we use a model without parametric classification heads since it is more suitable for dealing with novel classes. Novel class discovery is performed by directly clustering the feature spaces and class labels are assigned through the classic $k$ -means algorithm. Concretely, we learn a model initialization using the labeled data during offline training. During each continual learning session, we update the model using a soft neighborhood contrastive learning (see Fig. 2 (a)) on unlabeled data. To fully exploit the labeled data in offline learning, we further develop a bilevel optimization based on meta-learning to simulate the online learning scenario, so that the model is ready to adapt to new incoming unlabeled data and discover novel objects after the offline training (see Fig. 2 (b)). In the following, we describe these two parts of our method in detail.", + "bbox": [ + 496, + 597, + 893, + 839 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Contrastive learning based clustering network", + "text_level": 1, + "bbox": [ + 498, + 847, + 890, + 864 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Considering the characteristics of labeled and unlabeled data, we employ different contrastive learning strategies. To", + "bbox": [ + 498, + 869, + 893, + 902 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "1657", + "bbox": [ + 483, + 944, + 514, + 957 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/9e89f4bcee28c996ca8261db3b804012b7177c25da688e497b7b2acd27352edf.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 163, + 90, + 803, + 262 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/23015a8311b36a9bf85e73d19f28bb88e2f63c7cbffc3d6cda72c6b0713fc6b0.jpg", + "image_caption": [ + "Figure 2: Overview of the proposed MetaGCD. (a) Our soft neighborhood contrastive learning network aims to discriminate uncorrelated instances while absorbing correlated instances to learn discriminative representations. (b) Our meta-learning optimization strategy utilizes the offline labeled data to simulate the testing incremental learning process by sampling sequential learning tasks. By learning from these sampled sequential tasks, our model learns a good initialization, so that it can effectively adapt to discover new novel classes without forgetting old classes." + ], + "image_footnote": [], + "bbox": [ + 163, + 263, + 807, + 470 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "train on the labeled data, we utilize a combination of unsupervised and supervised contrastive losses. When discovering the latent classes in continually encountered unlabeled data, we propose to mine soft positive neighbors for each data instance to elevate the discriminative feature learning.", + "bbox": [ + 75, + 587, + 468, + 662 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.1.1 Representation learning on labeled data", + "text_level": 1, + "bbox": [ + 76, + 690, + 408, + 705 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To learn a robust and semantically meaningful representation on labeled data, we utilize both self-supervised [14] and supervised [22] contrastive losses. Let $\\mathbf{x}_i$ and $\\mathbf{x}_i'$ be two randomly augmented versions of $i^{th}$ instance sample, the unsupervised contrastive loss is expressed as:", + "bbox": [ + 75, + 717, + 467, + 792 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {i} ^ {u c l} = - \\log \\frac {\\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {i} ^ {\\prime} / \\tau\\right)}{\\sum_ {n} \\mathbb {I} _ {[ n \\neq i ]} \\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {n} / \\tau\\right)} \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 140, + 806, + 468, + 840 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbf{z}_i = \\phi(f(\\mathbf{x}_i))$ , $\\mathbb{I}_{[n \\neq i]}$ is an indicator function, and $\\tau$ is a temperature value. $f$ is the feature extractor, and $\\phi$ is a multi-layer perceptron (MLP) projection head.", + "bbox": [ + 76, + 854, + 468, + 900 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The supervised contrastive counterpart is expressed as:", + "bbox": [ + 517, + 587, + 880, + 602 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {i} ^ {s c l} = - \\frac {1}{| \\mathcal {N} (i) |} \\sum_ {q \\in \\mathcal {N} (i)} \\log \\frac {\\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {q} / \\tau\\right)}{\\sum_ {n} \\mathbb {I} _ {[ n \\neq i ]} \\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {n} / \\tau\\right)} \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 508, + 609, + 890, + 647 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathcal{N}(i)$ denotes the indices of instances having the same label as $\\mathbf{x}_i$ within the batch. Finally, these two losses are weighted by $\\lambda$ to train on the labeled data:", + "bbox": [ + 498, + 655, + 890, + 700 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {l a b e l e d}} = (1 - \\lambda) \\sum_ {i \\in B} \\mathcal {L} _ {i} ^ {u c l} + \\lambda \\sum_ {i \\in B} \\mathcal {L} _ {i} ^ {s c l} \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 557, + 708, + 890, + 739 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.1.2 Soft neighborhood contrastive learning on unlabeled data", + "text_level": 1, + "bbox": [ + 500, + 756, + 890, + 784 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "When learning on unlabeled data, only the unsupervised contrastive loss Eq. 1 can be used. However, the samples within the same class could be mistakenly treated as negatives due to the missing labels. In addition, the number of negative pairs significantly surpasses positive pairs. Such imbalanced loss contribution could be sub-optimal. Aligning the positive and negative pairs with the true classes", + "bbox": [ + 496, + 794, + 890, + 900 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "1658", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "emerges as a desired solution. [47] has attempted to address the limitations by mining more positive pairs in the neighbored of each data sample. However, the pseudo-positive pairs are treated equally, regardless of how close they are to that data sample. To address this issue, we propose to encode soft positive correlation among instance neighbors to achieve adaptive contribution, as shown in Fig. 2 (a).", + "bbox": [ + 75, + 90, + 468, + 196 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Specifically, for each $\\mathbf{x}_i$ , we first use the nearest neighbor operator on the projected features to select candidate neighbors. We denote them as $NN(\\mathbf{z}_i)_k$ with $k$ as the index. We then pass them and $\\mathbf{z}_i$ to an attention module to predict a set of positiveness values $\\mathbf{w}_i = \\{w_{ik}\\} \\in (0,1)$ to weight the contribution of $NN(\\mathbf{z}_i)_k$ to the loss. Accordingly, the soft neighborhood contrastive loss is defined as:", + "bbox": [ + 75, + 196, + 470, + 303 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {i} ^ {\\text {s o f t}} = - \\frac {1}{| N N (\\mathbf {z} _ {i}) |} \\sum_ {k \\in N N (\\mathbf {z} _ {i})} \\log \\frac {w _ {i k} \\cdot \\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {k} / \\tau\\right)}{\\sum_ {n} \\mathbb {I} _ {[ n \\neq i ]} \\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {n} / \\tau\\right)} \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 76, + 310, + 475, + 362 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Candidate neighborhood. For each batch of data, we first compute their features $\\mathcal{F}$ from the projection head at once. For each reference view $\\mathbf{x}_i$ , we retrieve nearest neighbors by comparing the cosine similarity to a threshold $\\epsilon$ as:", + "bbox": [ + 75, + 363, + 468, + 422 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nN N (\\mathbf {z} _ {i}) = \\{\\mathbf {F} \\}, \\text {f o r} \\mathbf {F} \\text {i n} \\mathcal {F}, \\text {i f} \\cos (\\mathbf {z} _ {i}, \\mathbf {F}) \\geq \\epsilon \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 116, + 431, + 468, + 450 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\mathbf{z}_i$ and $\\mathbf{F} \\in \\mathcal{F}$ are normalized before computation.", + "bbox": [ + 75, + 457, + 452, + 472 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Positiveness generation. Fig. 2 (a) shows an intuitive example of the candidate neighbors. The first two neighbors belong to the same category as the reference 'tiger' sample, while the $3^{rd}$ and $4^{th}$ neighbors are partially related (i.e., they belong to the 'lion' and 'leopard' categories, but not 'tiger'). The remaining instances are not related to 'tiger'. Therefore, the first four instances tend to be selected and they should contribute adaptively to the loss. We propose to learn an attention module to measure the soft correlations between the selected neighbors and the reference instance (instead of the binary form in [47]). Given two inputs $\\mathbf{z}_i$ and $NN(\\mathbf{z}_i)_k$ , we can calculate the positiveness score as:", + "bbox": [ + 75, + 472, + 468, + 654 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {w} _ {i} = \\operatorname {S o f t m a x} \\left[ f _ {1} \\left(\\mathbf {z} _ {i}\\right) \\times f _ {2} \\left(N N \\left(\\mathbf {z} _ {i}\\right) _ {k}\\right) ^ {T} \\right] \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 135, + 661, + 468, + 680 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $f_{1}(\\cdot)$ and $f_{2}(\\cdot)$ are the new projection layers and $\\times$ denotes the cross attention operator. Eq. 6 is then normalized so that $\\mathbf{w}_{i}$ has a max value as 1. Note that $f_{1}(\\cdot)$ and $f_{2}(\\cdot)$ can also be the non-parametric identity mappings, which are empirically found to be more effective. This observation may be attributed to the self-supervised learning paradigm, where the objective is to train the encoder effectively. Simplifying the attention module leads to less overfitting and improves learning attentive features.", + "bbox": [ + 75, + 686, + 468, + 824 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.2. Learning to incrementally discover categories", + "text_level": 1, + "bbox": [ + 76, + 832, + 464, + 849 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The main limitation of the prior works is that the labeled set $S^0$ is not fully exploited [7]. Instead of performing only representation learning on $S^0$ [21, 45], we borrow", + "bbox": [ + 75, + 854, + 468, + 901 + ], + "page_idx": 4 + }, + { + "type": "code", + "sub_type": "algorithm", + "code_caption": [ + "Algorithm 1 The optimization procedure of MetaGCD" + ], + "code_body": "Require: $\\alpha, \\beta, \\gamma$ : learning rates \nRequire: $S^0$ : training set of labeled classes \n1: randomly initialize parameters $\\theta$ \n2: while not converged do \n3: $\\mathcal{D} = \\left\\{\\left(\\mathcal{D}_{tr}^j,\\mathcal{D}_{te}^j\\right)\\right\\}_{j=0}^T$ \n4: ▷ sample a pseudo incremental sequence \n5: $\\mathcal{P} = \\emptyset$ ▷ empty cumulative pseudo test set \n6: $\\theta^{E,P}\\gets \\theta^{E,P} - \\gamma \\nabla_{\\theta^{E,P}}\\mathcal{L}_{labeled}(\\mathbf{x}_{tr}^0,\\mathbf{y}_{tr}^0;\\theta)$ \n7: ▷ update parameters using pseudo labeled classes \n8: $\\mathcal{P} = \\mathcal{P}\\cup \\mathcal{D}_{te}^{0}$ ▷ accumulate test set of sess-0 \n9: for $j = 1,\\dots,T$ do \n10: $\\tilde{\\theta}^{E,P} = \\theta^{E,P} - \\alpha \\nabla_{\\theta^{E,P}}\\mathcal{L}_{soft}(\\mathbf{x}_{tr}^j;\\theta)$ \n11: ▷ compute adapted params with unlabeled samples \n12: $\\mathcal{P} = \\mathcal{P}\\cup \\mathcal{D}_{te}^j$ ▷ accumulate test set of sess-j \n13: $\\theta \\gets \\theta -\\beta \\nabla_{\\theta}\\sum_{(\\mathcal{X},\\mathcal{Y})\\in \\mathcal{P}}\\mathcal{L}_{scl}(\\mathcal{X},\\mathcal{Y};\\tilde{\\theta}^E,\\tilde{\\theta}^P)$ \n15: ▷ update meta-params $\\theta$ to new session \n16: end for \n17: end while", + "bbox": [ + 500, + 108, + 890, + 385 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "the meta-learning paradigm (in particular MAML [12]) to learn how to continually discover new classes. In few-shot learning, during meta-training, MAML constructs few-shot tasks to mimic the meta-testing scenario to achieve learning to quickly adapt. In our C-GCD case, the online continual class discovery tasks can be viewed as the \"meta-testing\" stage. Therefore, we propose to simulate the continual setting using $S^0$ during offline training, as shown in Fig. 2 (b). We aim to produce a model initialization that is trained by aligning the training and evaluation objectives so that it is endowed with the capability to effectively discover novel classes with less forgetting during evaluation.", + "bbox": [ + 496, + 416, + 893, + 598 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Sequential task sampling. To mimic the evaluation process, we sample sequential learning tasks from $\\mathcal{S}^0$ [7]. Specifically, we first randomly separate the $S^0$ into pseudo labeled and pseudo unlabeled classes without overlapping. Next, we sample a sequence of $T + 1$ sessions, $\\mathcal{D} = \\{(\\mathcal{D}_{tr}^j,\\mathcal{D}_{te}^j)\\}_{j = 0}^T$ , where $\\mathcal{D}_{tr}^j$ and $\\mathcal{D}_{te}^j$ are the training and test set for the $j^{th}$ session. For the training splits $\\{\\mathcal{D}_{tr}^j\\}$ , we follow the evaluation protocol to only allow the first session to contain labeled data, (i.e., $\\mathcal{D}_{tr}^0 = \\{\\mathbf{x}_{tr}^0,\\mathbf{y}_{tr}^0\\}$ ) and the rest with unlabeled data (i.e., $\\mathcal{D}_{tr}^j = \\{\\mathbf{x}_{tr}^j\\}$ , for $j > 0$ ). We also set the first session to contain a larger number of samples, i.e., $\\left|\\mathcal{D}_{tr}^0\\right| \\gg \\left|\\mathcal{D}_{tr}^{j > 0}\\right|$ to simulate the C-GCD setting where the model is first trained during an offline training stage with a large amount of data. For the test splits $\\{\\mathcal{D}_{te}^j\\}$ , all of them contain labels that will be used during the optimization (i.e., $\\mathcal{D}_{te}^j = \\{\\mathbf{x}_{te}^j,\\mathbf{y}_{te}^j\\}, \\forall j$ ). Note that $\\mathcal{D}_{te}^j$ only contains the test data belonging to the current session $j$ .", + "bbox": [ + 496, + 599, + 893, + 867 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Meta-training. For each sampled sequence $\\mathcal{D}$ , we let the model continually explore the incoming unlabeled data in", + "bbox": [ + 498, + 869, + 893, + 901 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "1659", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "an unsupervised manner. To reduce the forgetting issue due to learning new knowledge, we utilize the bi-level optimization [12, 8, 7] to directly formulate incrementally discovering without forgetting as the meta-objective. The meta-learning procedure is illustrated in Alg. 1 and Fig. 2 (b). Concretely, we decouple the network as $\\theta = \\{\\theta^{E},\\theta^{P}\\}$ , where $\\theta^{E}$ and $\\theta^{P}$ are the encoder and projection layers. At each incremental session, we aim to evaluate all the classes that have encountered so far. Hence, at the beginning of each sequence, we define an empty cumulative pseudo test set $\\mathcal{P}$ to store the test samples from previous sessions. After that, we first train $\\theta$ on the pseudo labeled classes $(j = 0)$ using the unsupervised and supervised contrastive loss (Eq. 3). At each $j^{th}$ session $(j > 0)$ , we update $\\theta$ on unlabeled samples $\\mathcal{D}_{tr}^{j} = \\{\\mathbf{x}_{tr}^{j}\\}$ via a few gradient steps:", + "bbox": [ + 75, + 90, + 472, + 319 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\tilde {\\theta} ^ {E, P} = \\theta^ {E, P} - \\alpha \\nabla_ {\\theta^ {E, P}} \\mathcal {L} _ {s o f t} (\\mathbf {x} _ {t r} ^ {j}; \\theta) \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 145, + 329, + 468, + 349 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $\\mathcal{L}_{soft}(\\cdot)$ is the proposed soft neighborhood contrastive loss (Eq. 4). It aims to discriminate uncorrelated samples while absorbing correlated ones. By thoroughly exploring the unlabeled data, it maintains comprehensive old knowledge while efficiently discovering novel classes.", + "bbox": [ + 75, + 361, + 468, + 436 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Eq. 7 mimics how the model discovers novel classes on the incoming unlabeled data at test-time. Ideally, we like the adapted $\\tilde{\\theta}^{E,P}$ to perform well on all encountered classes. The test data from previous sessions and the current session separately reflect the catastrophic forgetting robustness and novel class discovery capability. Thus, we append $\\mathcal{D}_{te}^{j}$ to $\\mathcal{P}$ . Accordingly, the meta-objective is defined as follows for the outer loop of the meta-level optimization:", + "bbox": [ + 75, + 438, + 468, + 559 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\min _ {\\theta^ {E}, \\theta^ {P}} \\sum_ {(\\mathcal {X}, \\mathcal {Y}) \\in \\mathcal {P}} \\mathcal {L} _ {s c l} (\\mathcal {X}, \\mathcal {Y}; \\tilde {\\theta} ^ {E}, \\tilde {\\theta} ^ {P}) \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 145, + 571, + 468, + 598 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $\\mathcal{L}_{scl}(\\cdot)$ is the supervised contrastive loss in Eq. 1. Note that the optimization is performed on $\\theta$ , although $\\mathcal{L}_{scl}(\\cdot)$ is a function of $\\tilde{\\theta}^E$ and $\\tilde{\\theta}^P$ . The meta-objective in Eq. 8 is then optimized using gradient descent, as shown in Line 13 of Alg. 1. We empty $\\mathcal{P}$ when all $T + 1$ sessions are iterated. After meta-training, we obtain an initialization of the model $\\theta$ which has been specifically trained to discover and learn novel objects from a sequence of unlabeled data.", + "bbox": [ + 75, + 612, + 468, + 733 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Meta-testing. It is worth mentioning that the procedure in Alg. 1 aligns with the evaluation protocol. After discovering novel classes at each incremental session, the model is evaluated on all encountered classes. Our meta-objective optimizes the model towards what it is supposed to do at evaluation to maximize the performance. In addition, despite some uncertainties that may occur for unsupervised learning, the model is constrained by a fully supervised meta-objective. Thus, when training converges, the meta-model $\\theta$ is ready to discover novel classes while maintaining the old knowledge by only running Line 10 of Alg. 1.", + "bbox": [ + 75, + 734, + 468, + 901 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/98d8be3ab01e70657792e025a12bcd0abb27bcbd281b48741afebfd1d49bb5e0.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
DatasetLabeled SetUnlabeled Set
#class#image#class#image
CIFAR107280001022000
CIFAR100803200010018000
Tiny-ImageNet1506000020040000
", + "bbox": [ + 509, + 89, + 883, + 175 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 1: Datasets used in our experiments. We show the number of classes in the labeled and unlabeled sets, as well as the number of samples.", + "bbox": [ + 498, + 185, + 893, + 231 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 500, + 256, + 633, + 273 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Dataset and setup", + "text_level": 1, + "bbox": [ + 500, + 280, + 671, + 296 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Dataset. We construct the C-GCD benchmark using three widely used datasets as in NCD [40, 35, 47], i.e., CIFAR10 [23], CIFAR100 [23] and Tiny-ImageNet [25]. Each dataset is split into two subsets, 1) large-scale labeled samples accounting for $80\\%$ of the known classes data constitute a labeled set for offline training; and 2) the remaining data containing known and novel classes are used as an unlabeled set for continual object discovery. In Tab. 1, we summarize the dataset splits used in our training.", + "bbox": [ + 496, + 303, + 890, + 439 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Session-wise data split. All labeled samples $S^0$ are used for offline training in our setting. During the online incremental learning stage, the unlabeled samples are dynamically added (i.e., sessions $t \\geq 1$ ). Specifically, CIFAR10 is divided into 3 incremental sessions. In the $t^{th}(t > 0)$ session, 3000 unlabeled images from 1 novel class and 2000 unlabeled images from $7 + (t - 1) \\times 1$ known classes are added. CIFAR100 is divided into 4 sessions, in which 1500 unlabeled images from 5 novel classes and 2000 unlabeled images from $80 + (t - 1) \\times 5$ known classes are added in the $t^{th}$ session. The Tiny-ImageNet consists of 5 incremental sessions, each containing 3000 unlabeled images from 10 novel classes and 3000 unlabeled images from $150 + (t - 1) \\times 10$ known classes.", + "bbox": [ + 496, + 439, + 892, + 650 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Sequential task sampling. During offline training, we use $S^0$ to sample sequential tasks. We first split $S^0$ into non-overlapping pseudo labeled and novel classes (4/3 for CIFAR10, 60/20 for CIFAR100 and 100/50 for TinyImageNet). For each task, the pseudo labeled set is first used to warm up the model, followed by $T$ incremental sessions of unlabeled samples containing the pseudo labeled and novel classes. Both the session number and the number of novel classes in each offline incremental session are consistent with the online incremental learning scenario.", + "bbox": [ + 496, + 651, + 893, + 801 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Evaluation metrics. After learning the model on unlabeled samples at every online incremental stage, we follow [40] to measure the clustering accuracy between the ground truth labels $y_{i}$ and the model's predictions $\\hat{y}_{i}$ as:", + "bbox": [ + 496, + 801, + 893, + 863 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\nA C C = \\max _ {p \\in \\mathcal {P} (\\mathcal {Y})} \\frac {1}{N} \\sum \\left(\\mathbb {1} \\left\\{y _ {i} = p \\left(\\hat {y} _ {i}\\right) \\right\\}\\right), \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 558, + 871, + 890, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "1660", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/9638602ac314513ff3e5b49e7ce60efec97a91793da539da334c8184ad79a889.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodsCIFAR10 (Session Number)Final\nImpro.
123
AllOldNewAllOldNewAllOldNewAllOldNewAllOldNew
RankStats69.3170.2058.6365.2367.8651.2038.1650.0135.94+54.50+47.22+48.77
FRoST73.9281.1766.4569.5679.7358.0467.7370.8451.13+24.93+26.39+33.58
VanillaGCD89.2497.9781.8085.1396.6774.6086.4195.0376.75+6.25+2.20+7.96
GM90.0098.4177.4087.3999.0173.4687.8697.1578.93+4.80+0.08+5.78
MetaGCD(ours)95.3899.0789.1593.3498.8185.3992.6697.2384.71
MethodsCIFAR100 (Session Number)Final\nImpro.
1234
AllOldNewAllOldNewAllOldNewAllOldNewAllOldNew
RankStats62.3364.2231.6055.0158.5526.8551.7756.7025.4747.5154.5917.20+27.05+23.01+43.93
FRoST67.1468.5750.7367.0168.8252.6062.3565.4845.6755.8459.0642.95+18.72+18.54+18.18
VanillaGCD76.7877.9158.6073.6775.2960.7072.7774.7262.3371.4474.7558.20+3.12+2.85+2.93
GM78.2979.9166.0077.5879.6461.1374.5677.6058.1472.0275.9856.32+2.54+1.62+4.81
MetaGCD(ours)78.9679.3672.6078.6779.4166.8176.0678.2064.8774.5677.6061.13
MethodsTiny-ImageNet (Session Number)Final\nImpro.
1234
AllOldNewAllOldNewAllOldNewAllOldNewAllOldNew
RankStats62.3964.5435.0155.8952.2334.2049.8846.1728.3344.2042.8724.5036.0935.2015.76
FRoST64.9267.8446.2859.5061.8640.6057.8660.6339.1455.6859.7136.5550.4953.7633.37
VanillaGCD75.9278.1762.1574.5377.7356.1273.6474.8557.3170.6971.1354.3566.1567.1754.43
GM76.3279.5563.6075.4378.1057.4072.6376.2954.8070.5476.8051.5067.3172.0850.90
MetaGCD(ours)78.6779.4166.8077.8979.9561.4075.2377.8661.2072.0075.6157.5570.2471.5358.46
", + "bbox": [ + 81, + 88, + 890, + 452 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 2: Performance (in %) comparisons with the state-of-the-art methods on CIFAR10, CIFAR100, Tiny-ImageNet datasets. The results of other methods are obtained by running their released codes under the C-GCD setting.", + "bbox": [ + 75, + 463, + 892, + 494 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "where $N$ is the total number of test samples and $\\mathcal{P}(\\mathcal{V})$ is the set of all permutations of the class labels $\\mathcal{V}$ encountered so far. The optimal permutation can be obtained via the Hungarian algorithm [24]. Our main metric is ACC on 'All' classes, indicating the accuracy across all accumulated test sets so far. To decouple the evaluation on forgetting and discovery, we further report accuracy for both the 'Old' classes subset (samples in the test set belonging to previous known classes) and 'New' classes subset (samples in the test set belonging to novel classes).", + "bbox": [ + 75, + 521, + 470, + 674 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Implementation details. Following [40], we employ a vision transformer (ViT-B-16) [10] pretrained on ImageNet [9] with DINO [3] as the feature extractor throughout the paper. We use the Adam optimizer and the learning rates in Alg. 1 are set as $\\gamma = 0.1$ , $\\alpha = 0.001$ and $\\beta = 0.0001$ . We use a batch size of 256 and $\\lambda = 0.35$ to balance the losses in Eq. 3. Unless otherwise stated, we select the threshold $\\epsilon$ to be 0.85 in Eq. 5. At the meta-training stage, we first perform training on pseudo labeled set for 50 epochs, followed by 10 inner and 1 outer gradient updates for incremental sessions. At the meta-test stage, we directly perform 20 gradient updates to adapt using unlabeled samples. Furthermore, we follow standard practice in self-supervised learning to use the same projection head as in [3] and discard it at test-time.", + "bbox": [ + 75, + 688, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.2. Comparison with the state-of-the-art", + "text_level": 1, + "bbox": [ + 498, + 520, + 818, + 537 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Since this paper considers a new problem setting, there is no prior work that we can directly compare. Nevertheless, we choose SOTA methods on NCD and run their codes under our C-GCD setting, including RankStats [16], VanillaGCD [40], and recent continual NCD models FRoST [35], GM [45]. Both RankStats and FRoST train two classifiers on top of a shared feature representation. The first head is fed images from the labeled set and is trained with the cross-entropy loss, while the second head sees only images from unlabeled images of novel classes. In order to adapt RankStats and FRoST to C-GCD, we train them with a single classification head for the total number of classes in the dataset. The sequential version of VanillaGCD is adopted and serves as the baseline for our model. We leverage the original training mechanism for GM.", + "bbox": [ + 496, + 547, + 890, + 776 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In Tab. 2, we report the All/Old/New class accuracy per incremental session for all methods, and the relative improvement for the final session. As we can see, the proposed method consistently outperforms all other methods on all three datasets among the most incremental sessions. Specifically, our MetaGCD surpasses the most recent method GM by $5.78\\%$ , $4.81\\%$ and $7.56\\%$ on CIFAR10, CIFAR100 and Tiny-ImageNet datasets for the final New classes accuracy.", + "bbox": [ + 496, + 779, + 892, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "1661", + "bbox": [ + 483, + 944, + 513, + 957 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/610ff98fda1c4ad753c53e187dffc9b9c6bb80ec78ff22f1d01cede7029291a4.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodsCIFAR100 (Session Number)Average Acc
1234
AllOldNewAllOldNewAllOldNewAllOldNewmAmOmN
Baseline76.7877.9158.6073.6775.2960.7072.7774.6262.3371.4474.7558.2073.6775.6459.96
+LCN77.2978.5365.4475.2077.6763.0874.5575.9163.6372.6275.4359.4074.9276.8962.89
+LSP77.9278.4568.7876.5378.2264.7174.8677.2464.0973.3476.8760.6075.6677.7064.55
+Meta-learning78.9679.3672.6078.6779.4166.8176.0678.2064.8774.5677.6061.1377.0678.6466.35
", + "bbox": [ + 81, + 89, + 890, + 205 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 3: Ablation study of various components of our MetaGCD on the CIFAR100 dataset. We report 'All', 'Old' and 'New' class accuracy for each incremental session, and the average of all sessions such as mean 'All' (mA), mean 'Old' (mO) and mean 'New' accuracy (mN). Here CN denotes candidate neighbors and SP denotes soft positiveness.", + "bbox": [ + 75, + 215, + 892, + 262 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/087bc3da845b31f71935cb67300089dcd2710b6c820598ba73aedbda46680128.jpg", + "image_caption": [ + "Figure 3: Class-wise performance on the CIFAR100 dataset. The confusion matrices show that our model significantly improves the baseline for both known and novel classes (separated by the red line). Especially for novel classes, the confusion matrix of our method has more concentrated values along the diagonal." + ], + "image_footnote": [], + "bbox": [ + 81, + 300, + 267, + 440 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/635d80b87485e79afe54aa9a4c11cc66317cc68604c8c9e9969f87f7a21af487.jpg", + "image_caption": [ + "Figure 4: Hyper-parameter analysis on the CIFAR100 dataset regarding feature similarity threshold (left) and various numbers of novel classes (right). An appropriate threshold or the number of new classes helps to stabilize the training process and improve performance." + ], + "image_footnote": [], + "bbox": [ + 272, + 301, + 467, + 440 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Besides, our model outperforms the baseline VanillaGCD by $6.25\\%$ , $3.12\\%$ and $4.09\\%$ for the final All classes. We also report the class-wise performance via the confusion matrices shown in Fig. 3. It is obvious that the baseline performs poorly, especially on the novel classes. However, the proposed model has a significant gain in discovering novel classes. Moreover, less forgetting is observed in our method, as more values are concentrated on the diagonal.", + "bbox": [ + 75, + 574, + 468, + 695 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "4.3. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 708, + 230, + 724 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We conduct ablation studies on the CIFAR100 dataset to evaluate each component in our proposed framework.", + "bbox": [ + 75, + 732, + 468, + 762 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Importance of neighborhood. In our contrastive learning framework, we compute the soft correlation to allow more positive pairs to contribute to the loss. As reported in the second row of Tab. 3, considering the neighborhood achieves a performance gain of $1.25\\%$ (i.e., $74.92\\%$ v.s. $73.67\\%$ on the mean accuracy of All classes). The performance gain may come from the abundant comparisons from positive samples, which facilitates the current instance to align with more highly-correlated samples. We also conduct", + "bbox": [ + 75, + 763, + 468, + 901 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/92c7e533a3ce878c8b9505e8443b862ea114e97d3b7ae0fc0befb26766ed9c82.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 506, + 297, + 883, + 388 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "experiments to assess the sensitivity of threshold $\\epsilon$ when selecting the positive neighbor instances. Increasing $\\epsilon$ allows more strict positive pairs, but some partially related samples might be ignored. On the other hand, reducing $\\epsilon$ increases the likelihood of introducing true negative samples, which may negatively impact model performance. As empirically found in the left side of Fig. 4, a trade-off should be made, and a threshold of 0.85 achieves the best performance.", + "bbox": [ + 496, + 505, + 890, + 626 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Importance of soft positiveness. We then analyze the importance of soft positiveness to the recognition performance in the third row of Tab. 3. When we compute a correlation weight for each selected neighbor, the clustering accuracy on Novel classes increases from $62.89\\%$ to $64.55\\%$ . It indicates that the binary labeling strategy is insufficient to measure the correlation at the feature space, thus causing the backbone network to produce less discriminative representations compared with soft labeling methods. In the lower part of Fig. 2 (a), we show the correlation weight of selected neighbors with an input instance. The high score corresponds to the same category while the low score corresponds to less-correlated categories, which shows that our attention module is effective in modeling correlations between the input instance and each candidate neighbor.", + "bbox": [ + 496, + 627, + 892, + 853 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Effectiveness of meta-learning. Our meta-learning optimization strategy further improves All classes accuracy to $74.56\\%$ for the final incremental session in the last row", + "bbox": [ + 498, + 854, + 890, + 898 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "1662", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "of Tab. 3. It demonstrates the effectiveness of the proposed method where the meta-objective specifically forces the model to discover novel classes without forgetting old classes. Additionally, we analyze the impact of the number of novel classes that are sampled during meta-training. To investigate this, we train separate models by setting the number of novel classes in the range of $\\{1, 10\\}$ . As illustrated on the right side of Fig. 4, a larger number of classes for sequence tasks is more optimal. When there are fewer classes, the model is at a higher risk of overfitting to certain classes rather than learning how to incrementally learn.", + "bbox": [ + 75, + 90, + 472, + 258 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 271, + 194, + 286 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "In this paper, we propose a more realistic setting for real-world applications, namely C-GCD. The ultimate goal of C-GCD is to discover novel classes while keeping the old knowledge without forgetting. We propose a meta-learning based optimization strategy to directly optimize the network to learn how to incrementally discover with less forgetting. In addition, we introduce a soft neighborhood contrastive learning to utilize the soft positiveness to adaptively support the current instances from their neighbors. Extensive experiments on three datasets demonstrate the superiority of our method over state-of-the-art methods.", + "bbox": [ + 75, + 297, + 472, + 464 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Acknowledgments", + "text_level": 1, + "bbox": [ + 76, + 477, + 256, + 494 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "This work was supported by the Fundamental Research Funds for the Central Universities (No. 2022JBZY019), the National Key Research and Development Project (No. 2018AAA0100300) and an NSERC Discovery grant.", + "bbox": [ + 76, + 502, + 468, + 564 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 577, + 174, + 593 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Philip Bachman, R Devon Hjelm, and William Buchwalter. Learning representations by maximizing mutual information across views. Advances in Neural Information Processing Systems, 32, 2019.", + "[2] Peyman Bateni, Raghav Goyal, Vaden Masrani, Frank Wood, and Leonid Sigal. Improved few-shot visual classification. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 14493-14502, 2020.", + "[3] Mathilde Caron, Hugo Touvron, Ishan Misra, Hervé Jégou, Julien Mairal, Piotr Bojanowski, and Armand Joulin. Emerging properties in self-supervised vision transformers. In Proceedings of the IEEE International Conference on Computer Vision, pages 9650-9660, 2021.", + "[4] Can Chen, Yingxueff Zhang, Jie Fu, Xue Steve Liu, and Mark Coates. Bidirectional learning for offline infinite-width model-based optimization. NeurIPS, 2022.", + "[5] Can Chen, Shuhao Zheng, Xi Chen, Erqun Dong, Xue Steve Liu, Hao Liu, and Dejing Dou. Generalized dataweighting via class-level gradient manipulation. NeurIPS, 2021.", + "[6] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning" + ], + "bbox": [ + 86, + 602, + 470, + 901 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "of visual representations. In Proceedings of the IEEE International Conference on Machine Learning, pages 1597-1607, 2020.", + "[7] Zhixiang Chi, Li Gu, Huan Liu, Yang Wang, Yuanhao Yu, and Jin Tang. Meta-scl: A meta-learning approach for few-shot class incremental learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 14166-14175, 2022.", + "[8] Zhixiang Chi, Yang Wang, Yuanhao Yu, and Jin Tang. Test-time fast adaptation for dynamic scene deblurring via meta-auxiliary learning. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9137-9146, 2021.", + "[9] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 248-255, 2009.", + "[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In Proceedings of the IEEE International Conference on Learning Representations, 2021.", + "[11] Enrico Fini, Enver Sangineto, Stéphane Lathuilière, Zhun Zhong, Moin Nabi, and Elisa Ricci. A unified objective for novel class discovery. In Proceedings of the IEEE International Conference on Computer Vision, pages 9284-9292, 2021.", + "[12] Chelsea Finn, Pieter Abbeel, and Sergey Levine. Model-agnostic meta-learning for fast adaptation of deep networks. In Proceedings of International Conference on Machine Learning, pages 1126–1135, 2017.", + "[13] Li Gu, Zhixiang Chi, Huan Liu, Yuanhao Yu, and Yang Wang. Improving protonet for few-shot video object recognition: Winner of orbit challenge 2022. arXiv preprint arXiv:2210.00174, 2022.", + "[14] Michael Gutmann and Aapo Hyvarinen. Noise-contrastive estimation: A new estimation principle for unnormalized statistical models. In Proceedings of the International Conference on Artificial Intelligence and Statistics, pages 297–304, 2010.", + "[15] Kai Han, Sylvestre-Alvise Rebuffi, Sebastien Ehrhardt, Andrea Vedaldi, and Andrew Zisserman. Automatically discovering and learning new visual categories with ranking statistics. In International Conference on Learning Representations, 2020.", + "[16] Kai Han, Sylvestre-Alvise Rebuffi, Sebastien Ehrhardt, Andrea Vedaldi, and Andrew Zisserman. Autonovel: Automatically discovering and learning novel visual categories. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(10):6767-6781, 2021.", + "[17] Kai Han, Andrea Vedaldi, and Andrew Zisserman. Learning to discover novel visual categories via deep transfer clustering. In Proceedings of the IEEE International Conference on Computer Vision, pages 8401-8409, 2019.", + "[18] Kaiming He, Haoqi Fan, Yuxin Wu, Saining Xie, and Ross Girshick. Momentum contrast for unsupervised visual rep" + ], + "bbox": [ + 503, + 92, + 893, + 901 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "1663", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "resentation learning. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 9729-9738, 2020.", + "[19] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016.", + "[20] Khurram Javed and Martha White. Meta-learning representations for continual learning. Advances in Neural Information Processing Systems, 32, 2019.", + "[21] KJ Joseph, Sujoy Paul, Gaurav Aggarwal, Soma Biswas, Piyush Rai, Kai Han, and Vineeth N Balasubramanian. Novel class discovery without forgetting. In Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 570-586, 2022.", + "[22] Prannay Khosla, Piotr Teterwak, Chen Wang, Aaron Sarna, Yonglong Tian, Phillip Isola, Aaron Maschinot, Ce Liu, and Dilip Krishnan. Supervised contrastive learning. Advances in Neural Information Processing Systems, 33:18661-18673, 2020.", + "[23] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images. Handbook of Systemic Autoimmune Diseases, 1(4), 2009.", + "[24] Harold W Kuhn. The hungarian method for the assignment problem. Naval Research Logistics Quarterly, 2(1-2):83-97, 1955.", + "[25] Ya Le and Xuan Yang. Tiny imagenet visual recognition challenge. CS 231N, 7(7):3, 2015.", + "[26] Zhizhong Li and Derek Hoiem. Learning without forgetting. IEEE Transactions on Pattern Analysis and Machine Intelligence, 40(12):2935-2947, 2017.", + "[27] Hanwen Liang, Niamul Quader, Zhixiang Chi, Lizhe Chen, Peng Dai, Juwei Lu, and Yang Wang. Self-supervised spatiotemporal representation learning by exploiting video continuity. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 1564-1573, 2022.", + "[28] Huan Liu, Zhixiang Chi, Yuanhao Yu, Yang Wang, Jun Chen, and Jin Tang. Meta-auxiliary learning for future depth prediction in videos. In Proceedings of the IEEE Winter Conference on Applications of Computer Vision, pages 5756-5765, 2023.", + "[29] Huan Liu, Li Gu, Zhixiang Chi, Yang Wang, Yuanhao Yu, Jun Chen, and Jin Tang. Few-shot class-incremental learning via entropy-regularized data-free replay. In Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 146–162, 2022.", + "[30] Huan Liu, Zijun Wu, Liangyan Li, Sadaf Salehkalaibar, Jun Chen, and Keyan Wang. Towards multi-domain single image dehazing via test-time training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5831-5840, 2022.", + "[31] Yaoyao Liu, Yuting Su, An-An Liu, Bernt Schiele, and Qianru Sun. Mnemonics training: Multi-class incremental learning without forgetting. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 12245–12254, 2020.", + "[32] Yiwei Lu, Frank Yu, Mahesh Kumar Krishna Reddy, and Yang Wang. Few-shot scene-adaptive anomaly detection. In" + ], + "bbox": [ + 78, + 90, + 470, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 125-141, 2020.", + "[33] Tian Pan, Yibing Song, Tianyu Yang, Wenhao Jiang, and Wei Liu. Videomoco: Contrastive video representation learning with temporally adversarial examples. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 11205-11214, 2021.", + "[34] Sachin Ravi and Hugo Larochelle. Optimization as a model for few-shot learning. In International Conference on Learning Representations, 2017.", + "[35] Subhankar Roy, Mingxuan Liu, Zhun Zhong, Nicu Sebe, and Elisa Ricci. Class-incremental novel class discovery. In Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 317-333, 2022.", + "[36] Adam Santoro, Sergey Bartunov, Matthew Botvinick, Daan Wierstra, and Timothy Lillicrap. Meta-learning with memory-augmented neural networks. In International Conference on Machine Learning, pages 1842-1850, 2016.", + "[37] Karen Simonyan and Andrew Zisserman. Very deep convolutional networks for large-scale image recognition. In International Conference on Learning Representations, 2014.", + "[38] Jake Snell, Kevin Swersky, and Richard Zemel. Prototypical networks for few-shot learning. Advances in Neural Information Processing Systems, 30, 2017.", + "[39] Jae Woong Soh, Sunwoo Cho, and Nam Ik Cho. Meta-transfer learning for zero-shot super-resolution. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 3516-3525, 2020.", + "[40] Sagar Vaze, Kai Han, Andrea Vedaldi, and Andrew Zisserman. Generalized category discovery. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 7492-7501, 2022.", + "[41] Yue Wu, Yinpeng Chen, Lijuan Wang, Yuancheng Ye, Zicheng Liu, Yandong Guo, and Yun Fu. Large scale incremental learning. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 374-382, 2019.", + "[42] Yanan Wu, Tengfei Liang, Songhe Feng, Yi Jin, Gengyu Lyu, Haojun Fei, and Yang Wang. Metazscil: A meta-learning approach for generalized zero-shot class incremental learning. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 37, pages 10408-10416, 2023.", + "[43] Chi Zhang, Nan Song, Guosheng Lin, Yun Zheng, Pan Pan, and Yinghui Xu. Few-shot incremental learning with continually evolved classifiers. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 12455–12464, 2021.", + "[44] Marvin Zhang, Henrik Marklund, Nikita Dhawan, Abhishek Gupta, Sergey Levine, and Chelsea Finn. Adaptive risk minimization: Learning to adapt to domain shift. Advances in Neural Information Processing Systems, 34:23664-23678, 2021.", + "[45] Xinwei Zhang, Jianwen Jiang, Yutong Feng, Zhi-Fan Wu, Xibin Zhao, Hai Wan, Mingqian Tang, Rong Jin, and Yue Gao. Grow and merge: A unified framework for continuous categories discovery. Advances in Neural Information Processing Systems, 2022." + ], + "bbox": [ + 501, + 92, + 890, + 898 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "1664", + "bbox": [ + 483, + 944, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[46] Tao Zhong, Zhixiang Chi, Li Gu, Yang Wang, Yuanhao Yu, and Jin Tang. Meta-dmoe: Adapting to domain shift by metadata distillation from mixture-of-experts. Advances in Neural Information Processing Systems, 35:22243-22257, 2022.", + "[47] Zhun Zhong, Enrico Fini, Subhankar Roy, Zhiming Luo, Elisa Ricci, and Nicu Sebe. Neighborhood contrastive learning for novel class discovery. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 10867-10875, 2021." + ], + "bbox": [ + 78, + 90, + 468, + 218 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "1665", + "bbox": [ + 483, + 945, + 514, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/991c02f6-2cc1-4391-a19c-b8559690aace_model.json b/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/991c02f6-2cc1-4391-a19c-b8559690aace_model.json new file mode 100644 index 0000000000000000000000000000000000000000..852dd05a5acc8ce5fe48aa9dc4a0b4d0fd105aa6 --- /dev/null +++ b/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/991c02f6-2cc1-4391-a19c-b8559690aace_model.json @@ -0,0 +1,1993 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.092, + 0.131, + 0.88, + 0.154 + ], + "angle": 0, + "content": "MetaGCD: Learning to Continually Learn in Generalized Category Discovery" + }, + { + "type": "text", + "bbox": [ + 0.265, + 0.18, + 0.741, + 0.199 + ], + "angle": 0, + "content": "Yanan Wu\\(^{1,2*}\\), Zhixiang Chi\\(^{3*}\\), Yang Wang\\(^{4}\\), Songhe Feng\\(^{1,2\\dagger}\\)" + }, + { + "type": "text", + "bbox": [ + 0.214, + 0.199, + 0.798, + 0.234 + ], + "angle": 0, + "content": "1Key Laboratory of Big Data & Artificial Intelligence in Transportation, Ministry of Education, Beijing Jiaotong University, Beijing, 100044, China" + }, + { + "type": "text", + "bbox": [ + 0.092, + 0.234, + 0.912, + 0.305 + ], + "angle": 0, + "content": "\\(^{2}\\)School of Computer and Information Technology, Beijing Jiaotong University, Beijing, 100044, China \n\\(^{3}\\)Department of Electrical and Computer Engineering, University of Toronto, Toronto, M5G1V7, Canada \n\\(^{4}\\)Department of Computer Science and Software Engineering, Concordia University, Montreal, H3G2J1, Canada" + }, + { + "type": "text", + "bbox": [ + 0.137, + 0.308, + 0.862, + 0.323 + ], + "angle": 0, + "content": "{ynwu0510,shfeng}@bjtu.edu.cn,zhixiang.chi@mail.utoronto.ca,yang.wang@concordia.ca" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.357, + 0.313, + 0.373 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.389, + 0.474, + 0.736 + ], + "angle": 0, + "content": "In this paper, we consider a real-world scenario where a model that is trained on pre-defined classes continually encounters unlabeled data that contains both known and novel classes. The goal is to continually discover novel classes while maintaining the performance in known classes. We name the setting Continual Generalized Category Discovery (C-GCD). Existing methods for novel class discovery cannot directly handle the C-GCD setting due to some unrealistic assumptions, such as the unlabeled data only containing novel classes. Furthermore, they fail to discover novel classes in a continual fashion. In this work, we lift all these assumptions and propose an approach, called MetaGCD, to learn how to incrementally discover with less forgetting. Our proposed method uses a meta-learning framework and leverages the offline labeled data to simulate the testing incremental learning process. A meta-objective is defined to revolve around two conflicting learning objectives to achieve novel class discovery without forgetting. Furthermore, a soft neighborhood-based contrastive network is proposed to discriminate uncorrelated images while attracting correlated images. We build strong baselines and conduct extensive experiments on three widely used benchmarks to demonstrate the superiority of our method." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.765, + 0.208, + 0.781 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.79, + 0.47, + 0.867 + ], + "angle": 0, + "content": "Object categories in real-world environments are dynamically evolving and expanding over time. However, conventional deep learning-based visual recognition methods normally focus on closed-world scenarios with pre-defined categories [19, 37]. Such systems are brittle when deployed to" + }, + { + "type": "image", + "bbox": [ + 0.507, + 0.355, + 0.889, + 0.571 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.58, + 0.895, + 0.702 + ], + "angle": 0, + "content": "Figure 1: Illustration of our C-GCD setting. During the offline training, we learn an initial model based on training samples of the labeled set. During each subsequent online incremental learning, we are given some unlabeled images belonging to both known and novel classes. Our goal is to update the model in each incremental session so that the model can maintain the performance on old classes while discovering novel classes." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.733, + 0.893, + 0.793 + ], + "angle": 0, + "content": "an ever-changing realistic open-world setting, where object instances may come from new categories. In contrast, recognizing the known categories and utilizing them to discern the unknowns are intrinsic to human perception." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.796, + 0.895, + 0.902 + ], + "angle": 0, + "content": "Recently, discovering the novel classes among unlabeled data has been an active area of research [15, 11, 40, 35, 45]. However, most prior works make several assumptions that are unrealistic in practice. For example, the works in [15, 11, 40] assume the co-existence of both labeled data (with known classes) and unlabeled data (contains potential unknown classes to be discovered) at the training phase and" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.875, + 0.34, + 0.888 + ], + "angle": 0, + "content": "*The authors contributed equally to this work." + }, + { + "type": "page_footnote", + "bbox": [ + 0.098, + 0.888, + 0.224, + 0.9 + ], + "angle": 0, + "content": "† Corresponding Author" + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.875, + 0.34, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "1655" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.244 + ], + "angle": 0, + "content": "the models are learned from scratch. This leads to repetitive large-scale training every time when new classes are expected to be discovered. The works in [15, 11, 35, 45] assume the newly encountered unlabeled data only belongs to the novel classes. This is unrealistic in practice. To meet such conditions, a rigorous filtering method is needed to precisely filter out known class data to avoid degenerate solutions. Due to these limitations, none of these works can be used to build recognition systems that can deal with evolving object categories sequentially over a long time horizon." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.247, + 0.473, + 0.626 + ], + "angle": 0, + "content": "In this paper, we consider a more flexible setting for real-world applications. Let us consider the application of home robots. The robots are equipped with an offline trained object recognition model on pre-defined categories during manufacturing. After deployment, the robots are expected to operate in diverse environments. While operating, they continually receive data that belongs to known and possibly unknown classes. Ideally, we would like the robots to continually discover and learn novel classes from such data. We dub such a setting as Continuous Generalized Class Discovery (C-GCD). As shown in Fig. 1, C-GCD has two phases: 1) an offline training phase that allows the model to be trained on large-scale labeled data with pre-defined classes; 2) when the model is deployed, it continually encounters unlabeled data that comes from both known and novel classes on a longer horizon. At each incremental session, the data from the previous sessions is inaccessible. The model needs to precisely classify the known classes and discover novel ones to expand its knowledge base. Obviously, the main challenge of C-GCD is to discover the novel classes among unlabeled images that contain both known and unknown categories while maintaining the performance on old classes. However, learning novel knowledge normally leads to notorious catastrophic forgetting [7], which further exacerbates the model performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.629, + 0.473, + 0.901 + ], + "angle": 0, + "content": "There are some initial attempts on C-GCD [21, 45]. However, they only consider C-GCD at the deployment stage mentioned above. The offline training stage is not fully exploited in these works. Concretely, the labeled data during offline training is only used for pre-training model representations. Therefore, the model at the offline stage is unaware of its subsequent learning duty (discover novel classes and retain the performance of known classes) [8] and is also prone to overfit to the labeled set [40]. Such learning objective misalignment leads to cumbersome heuristic strategies to facilitate the new learning task while keeping the previous knowledge. For example, to learn the novel classes, [21] requires a self-labeling method, which may cause error propagation. A routing strategy is also required to determine the known and novel classifier heads. [45] relies on a thresholding method to filter novel instances. However, the overall robustness of the method can be sensitive to the threshold. To alleviate the" + }, + { + "type": "text", + "bbox": [ + 0.497, + 0.092, + 0.892, + 0.198 + ], + "angle": 0, + "content": "forgetting issues, [21, 45] propose to distill the knowledge from the pre-trained base models. Data replay is also utilized to either directly select representative labeled exemplars [45] or generate pseudo-latent representations from them [21]. Consequently, the base models and the replay buffers have to be stored locally which may cause storage problems, especially in a resource-constraint environment." + }, + { + "type": "text", + "bbox": [ + 0.497, + 0.199, + 0.893, + 0.514 + ], + "angle": 0, + "content": "In this work, we propose a fully learning-based solution, named MetaGCD, to minimize the hand-engineered heuristics in prior works. Concretely, at the offline training phase, instead of pre-training a model representation, we directly train an initialization that is learned to discover novel categories with less forgetting when deployed. It is realized by meta-learning-based bi-level optimization [12] to couple the offline training and downstream learning objectives. During the offline training, we simulate the testing scenario and construct pseudo incremental novel class discovery sessions using the labeled data. At each incremental session, we discover novel classes by updating the model using an unsupervised contrastive loss. The meta-objective is then defined by validating the updated model on all classes encountered on a labeled pseudo test set. Therefore, the meta-objective of the offline training is aligned with the evaluation protocol at deployment. It enforces the model to learn to balance two conflicting objectives, namely discovering new objects and not-forgetting old objects. The meta-objective also reinforces the unsupervised updated model to be supervised by the true labels to ensure valid novel class discovery." + }, + { + "type": "text", + "bbox": [ + 0.497, + 0.515, + 0.894, + 0.68 + ], + "angle": 0, + "content": "MetaGCD uses unsupervised contrastive learning to explore the relationship among instances for novel class discovery. Therefore, it is less prone to label overfitting [40]. However, we observe that the negative pairs in contrastive learning normally dominate the loss function. So we further propose soft neighborhood contrastive learning to mine more positiveness. Concretely, for each image instance, we select the nearest candidate neighbors within the batch to treat them as soft positive samples to contribute to the discriminative feature learning. Overall, our contributions are summarised as follows:" + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.689, + 0.892, + 0.765 + ], + "angle": 0, + "content": "- We consider a realistic setting C-GCD for applications in real-world scenarios. It allows the model trained on pre-defined classes to continually explore novel classes through incoming unlabeled data while simultaneously keeping the performance of known classes." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.766, + 0.892, + 0.826 + ], + "angle": 0, + "content": "- We propose a meta-learning approach where the learning objective is well aligned with the evaluation protocol during testing. It directly optimizes the model to achieve novel object discovery without forgetting." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.826, + 0.892, + 0.871 + ], + "angle": 0, + "content": "- A soft neighborhood contrastive learning method is also proposed to mine more soft positive pairs to elevate the discovery capability." + }, + { + "type": "text", + "bbox": [ + 0.518, + 0.871, + 0.892, + 0.902 + ], + "angle": 0, + "content": "- We establish strong baselines and show that our method achieves superior performance with less hand" + }, + { + "type": "list", + "bbox": [ + 0.518, + 0.689, + 0.892, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "1656" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.11, + 0.092, + 0.441, + 0.108 + ], + "angle": 0, + "content": "engineered design through extensive experiments." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.12, + 0.22, + 0.136 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.146, + 0.473, + 0.599 + ], + "angle": 0, + "content": "Discovering novel classes. Novel Class Discovery (NCD) aims to discover the novel classes from unlabeled data by utilizing the prior knowledge from the labeled data [15, 11, 17]. However, NCD assumes that the unlabeled data only belongs to the novel classes, which is unrealistic. Alternatively, a generalized version of NCD (GCD) [40] relaxes such constrain. Although GCD allows the unlabeled data to contain both known and novel classes, they are both required to be present in the training phase. It leads to repetitive large-scale training when different groups of unlabeled data are continually presented to the recognition system. Recently, a class incremental variant of NCD (class-iNCD) is proposed to learn the tasks of labeled known and unlabeled novel classes sequentially [35]. When learning the novel classes, the data of old classes are inaccessible. In the end, the model is evaluated on all encountered classes. Nevertheless, only a few incremental sessions containing unlabeled novel classes are allowed in class-iNCD. This limitation hinders its applicability under the realistic setting with continually evolved object categories. Our proposed C-GCD alleviates the above limitations in real-world scenarios. Our approach can learn from labeled pre-defined classes during offline training, and then continuously encounter unlabeled data with both known and novel classes after deployment. Our model will learn to discover novel classes without forgetting old classes. C-GCD is also related to the classic class-incremental setting [26, 41, 31, 29]. But C-GCD is more challenging as the newly evolved classes are unlabeled and an automatic class discovery mechanism is required [21]." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.599, + 0.473, + 0.825 + ], + "angle": 0, + "content": "Meta-learning. Existing meta-learning methods can be categorized into: 1) model-based [36, 2, 4]; 2) Optimization-based [34, 12, 5]; and 3) metric-based [38]. Typical meta-learning methods utilize bi-level optimization to train a model that is applicable for downstream adaptations. Our work is built upon MAML [12], which trains a model initialization through episodes of tasks for fast adaptation via gradient updates. Such learning paradigm has been widely applied in different vision tasks, such as test-time adaptation [39, 28, 32, 30], continual learning [43, 20, 42] and domain shift [44, 46, 13]. In our case, the adaptation is achieved in an unsupervised manner, and the bi-level optimization is utilized to combine two conflicting learning objectives: discovering the novel classes without forgetting the old classes." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.825, + 0.473, + 0.903 + ], + "angle": 0, + "content": "Contrastive learning. Contrastive learning has been popular in self-supervised visual representation learning [1, 6, 18, 33, 27]. It explores the relationships among data instances by constructing positive and negative pairs. Therefore, the overfitting on the label space is reduced to im" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.895, + 0.199 + ], + "angle": 0, + "content": "prove the generalization of downstream tasks. Zhong et al. [47] apply contrastive learning to discover novel classes by exploring the data neighborhood and choosing pseudopositive pairs. However, those pseudo-positive pairs contribute equally regardless of their closeness compared to the reference sample. In this work, we introduce the soft positiveness concept to allow adaptive contribution." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.21, + 0.712, + 0.227 + ], + "angle": 0, + "content": "3. The Proposed Method" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.235, + 0.895, + 0.597 + ], + "angle": 0, + "content": "Problem definition. The goal of C-GCD is to have the offline trained model continually discover and learn novel object classes from unlabeled data containing both known and novel classes. We define a sequence of \\(T\\) learning sessions \\(\\{S^0, S^1, \\dots, S^T\\}\\). Let \\(x^t \\in \\mathcal{X}^t\\) and \\(y^t \\in \\mathcal{Y}^t\\) denote the input and label space at session \\(t\\). We represent each session as: \\(S^0 = \\{(\\mathbf{x}_i^0, \\mathbf{y}_i^0)\\}_{i=1}^{Z_0}\\) and \\(S^t = \\{(\\mathbf{x}_i^t)\\}_{i=1}^{Z_t}\\). Note, only the first session (i.e., \\(t = 0\\)) contains large-scale labeled samples. As for \\(t > 0\\), \\(S^t\\) only contains unlabeled data. At the \\(t^{th}\\) session, only \\(S^t\\) is accessible, and the incoming data belongs to both learned known class from previous sessions and novel classes. Therefore, we can denote \\(\\mathcal{Y}^t = \\mathcal{Y}^{t-1} \\cup \\mathcal{Y}_n^t\\), where \\(\\mathcal{Y}_n^t\\) represents the novel classes to be discovered at session \\(t\\). After learning on \\(S^t\\), the model is evaluated on all test images accumulated until session \\(t\\) to test the performance on \\(\\mathcal{Y}^{t-1}\\) (ideally the model should not forget old classes) and the discovery capability on \\(\\mathcal{Y}_n^t\\). Compared with previous works [15, 11, 35, 45], C-GCD is much more challenging due to several factors. First, the unlabeled data contains both known and unknown classes, i.e., \\(\\mathcal{Y}^t = \\mathcal{Y}^{t-1} \\cup \\mathcal{Y}_n^t\\). Second, labeled data is absent at \\(t > 0\\), i.e., \\(S^0 \\cup S^t = \\emptyset\\) where \\(t > 0\\). Finally, since C-GCD operates on a long horizon, i.e., \\(t \\gg 1\\), the catastrophic forgetting issue is more severe." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.598, + 0.895, + 0.84 + ], + "angle": 0, + "content": "Method overview. Fig. 2 shows an overview of MetaGCD. Following [40], we use a model without parametric classification heads since it is more suitable for dealing with novel classes. Novel class discovery is performed by directly clustering the feature spaces and class labels are assigned through the classic \\( k \\)-means algorithm. Concretely, we learn a model initialization using the labeled data during offline training. During each continual learning session, we update the model using a soft neighborhood contrastive learning (see Fig. 2 (a)) on unlabeled data. To fully exploit the labeled data in offline learning, we further develop a bilevel optimization based on meta-learning to simulate the online learning scenario, so that the model is ready to adapt to new incoming unlabeled data and discover novel objects after the offline training (see Fig. 2 (b)). In the following, we describe these two parts of our method in detail." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.848, + 0.892, + 0.865 + ], + "angle": 0, + "content": "3.1. Contrastive learning based clustering network" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Considering the characteristics of labeled and unlabeled data, we employ different contrastive learning strategies. To" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.958 + ], + "angle": 0, + "content": "1657" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.164, + 0.092, + 0.805, + 0.263 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.164, + 0.264, + 0.808, + 0.472 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.485, + 0.892, + 0.56 + ], + "angle": 0, + "content": "Figure 2: Overview of the proposed MetaGCD. (a) Our soft neighborhood contrastive learning network aims to discriminate uncorrelated instances while absorbing correlated instances to learn discriminative representations. (b) Our meta-learning optimization strategy utilizes the offline labeled data to simulate the testing incremental learning process by sampling sequential learning tasks. By learning from these sampled sequential tasks, our model learns a good initialization, so that it can effectively adapt to discover new novel classes without forgetting old classes." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.588, + 0.469, + 0.663 + ], + "angle": 0, + "content": "train on the labeled data, we utilize a combination of unsupervised and supervised contrastive losses. When discovering the latent classes in continually encountered unlabeled data, we propose to mine soft positive neighbors for each data instance to elevate the discriminative feature learning." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.691, + 0.409, + 0.706 + ], + "angle": 0, + "content": "3.1.1 Representation learning on labeled data" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.718, + 0.468, + 0.793 + ], + "angle": 0, + "content": "To learn a robust and semantically meaningful representation on labeled data, we utilize both self-supervised [14] and supervised [22] contrastive losses. Let \\(\\mathbf{x}_i\\) and \\(\\mathbf{x}_i'\\) be two randomly augmented versions of \\(i^{th}\\) instance sample, the unsupervised contrastive loss is expressed as:" + }, + { + "type": "equation", + "bbox": [ + 0.141, + 0.807, + 0.469, + 0.842 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {i} ^ {u c l} = - \\log \\frac {\\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {i} ^ {\\prime} / \\tau\\right)}{\\sum_ {n} \\mathbb {I} _ {[ n \\neq i ]} \\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {n} / \\tau\\right)} \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.469, + 0.901 + ], + "angle": 0, + "content": "where \\(\\mathbf{z}_i = \\phi(f(\\mathbf{x}_i))\\), \\(\\mathbb{I}_{[n \\neq i]}\\) is an indicator function, and \\(\\tau\\) is a temperature value. \\(f\\) is the feature extractor, and \\(\\phi\\) is a multi-layer perceptron (MLP) projection head." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.588, + 0.882, + 0.603 + ], + "angle": 0, + "content": "The supervised contrastive counterpart is expressed as:" + }, + { + "type": "equation", + "bbox": [ + 0.509, + 0.61, + 0.891, + 0.648 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {i} ^ {s c l} = - \\frac {1}{| \\mathcal {N} (i) |} \\sum_ {q \\in \\mathcal {N} (i)} \\log \\frac {\\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {q} / \\tau\\right)}{\\sum_ {n} \\mathbb {I} _ {[ n \\neq i ]} \\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {n} / \\tau\\right)} \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.656, + 0.892, + 0.701 + ], + "angle": 0, + "content": "where \\(\\mathcal{N}(i)\\) denotes the indices of instances having the same label as \\(\\mathbf{x}_i\\) within the batch. Finally, these two losses are weighted by \\(\\lambda\\) to train on the labeled data:" + }, + { + "type": "equation", + "bbox": [ + 0.558, + 0.709, + 0.891, + 0.74 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {l a b e l e d}} = (1 - \\lambda) \\sum_ {i \\in B} \\mathcal {L} _ {i} ^ {u c l} + \\lambda \\sum_ {i \\in B} \\mathcal {L} _ {i} ^ {s c l} \\tag {3}\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.757, + 0.891, + 0.785 + ], + "angle": 0, + "content": "3.1.2 Soft neighborhood contrastive learning on unlabeled data" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.795, + 0.892, + 0.901 + ], + "angle": 0, + "content": "When learning on unlabeled data, only the unsupervised contrastive loss Eq. 1 can be used. However, the samples within the same class could be mistakenly treated as negatives due to the missing labels. In addition, the number of negative pairs significantly surpasses positive pairs. Such imbalanced loss contribution could be sub-optimal. Aligning the positive and negative pairs with the true classes" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "1658" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.198 + ], + "angle": 0, + "content": "emerges as a desired solution. [47] has attempted to address the limitations by mining more positive pairs in the neighbored of each data sample. However, the pseudo-positive pairs are treated equally, regardless of how close they are to that data sample. To address this issue, we propose to encode soft positive correlation among instance neighbors to achieve adaptive contribution, as shown in Fig. 2 (a)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.198, + 0.471, + 0.304 + ], + "angle": 0, + "content": "Specifically, for each \\(\\mathbf{x}_i\\), we first use the nearest neighbor operator on the projected features to select candidate neighbors. We denote them as \\(NN(\\mathbf{z}_i)_k\\) with \\(k\\) as the index. We then pass them and \\(\\mathbf{z}_i\\) to an attention module to predict a set of positiveness values \\(\\mathbf{w}_i = \\{w_{ik}\\} \\in (0,1)\\) to weight the contribution of \\(NN(\\mathbf{z}_i)_k\\) to the loss. Accordingly, the soft neighborhood contrastive loss is defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.078, + 0.311, + 0.477, + 0.363 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {i} ^ {\\text {s o f t}} = - \\frac {1}{| N N (\\mathbf {z} _ {i}) |} \\sum_ {k \\in N N (\\mathbf {z} _ {i})} \\log \\frac {w _ {i k} \\cdot \\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {k} / \\tau\\right)}{\\sum_ {n} \\mathbb {I} _ {[ n \\neq i ]} \\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {n} / \\tau\\right)} \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.364, + 0.47, + 0.424 + ], + "angle": 0, + "content": "Candidate neighborhood. For each batch of data, we first compute their features \\(\\mathcal{F}\\) from the projection head at once. For each reference view \\(\\mathbf{x}_i\\), we retrieve nearest neighbors by comparing the cosine similarity to a threshold \\(\\epsilon\\) as:" + }, + { + "type": "equation", + "bbox": [ + 0.117, + 0.433, + 0.47, + 0.451 + ], + "angle": 0, + "content": "\\[\nN N (\\mathbf {z} _ {i}) = \\{\\mathbf {F} \\}, \\text {f o r} \\mathbf {F} \\text {i n} \\mathcal {F}, \\text {i f} \\cos (\\mathbf {z} _ {i}, \\mathbf {F}) \\geq \\epsilon \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.458, + 0.453, + 0.473 + ], + "angle": 0, + "content": "where \\(\\mathbf{z}_i\\) and \\(\\mathbf{F} \\in \\mathcal{F}\\) are normalized before computation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.473, + 0.47, + 0.655 + ], + "angle": 0, + "content": "Positiveness generation. Fig. 2 (a) shows an intuitive example of the candidate neighbors. The first two neighbors belong to the same category as the reference 'tiger' sample, while the \\(3^{rd}\\) and \\(4^{th}\\) neighbors are partially related (i.e., they belong to the 'lion' and 'leopard' categories, but not 'tiger'). The remaining instances are not related to 'tiger'. Therefore, the first four instances tend to be selected and they should contribute adaptively to the loss. We propose to learn an attention module to measure the soft correlations between the selected neighbors and the reference instance (instead of the binary form in [47]). Given two inputs \\(\\mathbf{z}_i\\) and \\(NN(\\mathbf{z}_i)_k\\), we can calculate the positiveness score as:" + }, + { + "type": "equation", + "bbox": [ + 0.137, + 0.662, + 0.469, + 0.681 + ], + "angle": 0, + "content": "\\[\n\\mathbf {w} _ {i} = \\operatorname {S o f t m a x} \\left[ f _ {1} \\left(\\mathbf {z} _ {i}\\right) \\times f _ {2} \\left(N N \\left(\\mathbf {z} _ {i}\\right) _ {k}\\right) ^ {T} \\right] \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.688, + 0.47, + 0.825 + ], + "angle": 0, + "content": "where \\( f_{1}(\\cdot) \\) and \\( f_{2}(\\cdot) \\) are the new projection layers and \\( \\times \\) denotes the cross attention operator. Eq. 6 is then normalized so that \\( \\mathbf{w}_{i} \\) has a max value as 1. Note that \\( f_{1}(\\cdot) \\) and \\( f_{2}(\\cdot) \\) can also be the non-parametric identity mappings, which are empirically found to be more effective. This observation may be attributed to the self-supervised learning paradigm, where the objective is to train the encoder effectively. Simplifying the attention module leads to less overfitting and improves learning attentive features." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.833, + 0.465, + 0.85 + ], + "angle": 0, + "content": "3.2. Learning to incrementally discover categories" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.47, + 0.902 + ], + "angle": 0, + "content": "The main limitation of the prior works is that the labeled set \\(S^0\\) is not fully exploited [7]. Instead of performing only representation learning on \\(S^0\\) [21, 45], we borrow" + }, + { + "type": "code_caption", + "bbox": [ + 0.501, + 0.091, + 0.866, + 0.107 + ], + "angle": 0, + "content": "Algorithm 1 The optimization procedure of MetaGCD" + }, + { + "type": "algorithm", + "bbox": [ + 0.501, + 0.109, + 0.892, + 0.386 + ], + "angle": 0, + "content": "Require: \\(\\alpha, \\beta, \\gamma\\): learning rates \nRequire: \\(S^0\\): training set of labeled classes \n1: randomly initialize parameters \\(\\theta\\) \n2: while not converged do \n3: \\(\\mathcal{D} = \\left\\{\\left(\\mathcal{D}_{tr}^j,\\mathcal{D}_{te}^j\\right)\\right\\}_{j=0}^T\\) \n4: ▷ sample a pseudo incremental sequence \n5: \\(\\mathcal{P} = \\emptyset\\) ▷ empty cumulative pseudo test set \n6: \\(\\theta^{E,P}\\gets \\theta^{E,P} - \\gamma \\nabla_{\\theta^{E,P}}\\mathcal{L}_{labeled}(\\mathbf{x}_{tr}^0,\\mathbf{y}_{tr}^0;\\theta)\\) \n7: ▷ update parameters using pseudo labeled classes \n8: \\(\\mathcal{P} = \\mathcal{P}\\cup \\mathcal{D}_{te}^{0}\\) ▷ accumulate test set of sess-0 \n9: for \\(j = 1,\\dots,T\\) do \n10: \\(\\tilde{\\theta}^{E,P} = \\theta^{E,P} - \\alpha \\nabla_{\\theta^{E,P}}\\mathcal{L}_{soft}(\\mathbf{x}_{tr}^j;\\theta)\\) \n11: ▷ compute adapted params with unlabeled samples \n12: \\(\\mathcal{P} = \\mathcal{P}\\cup \\mathcal{D}_{te}^j\\) ▷ accumulate test set of sess-j \n13: \\(\\theta \\gets \\theta -\\beta \\nabla_{\\theta}\\sum_{(\\mathcal{X},\\mathcal{Y})\\in \\mathcal{P}}\\mathcal{L}_{scl}(\\mathcal{X},\\mathcal{Y};\\tilde{\\theta}^E,\\tilde{\\theta}^P)\\) \n15: ▷ update meta-params \\(\\theta\\) to new session \n16: end for \n17: end while" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.417, + 0.895, + 0.599 + ], + "angle": 0, + "content": "the meta-learning paradigm (in particular MAML [12]) to learn how to continually discover new classes. In few-shot learning, during meta-training, MAML constructs few-shot tasks to mimic the meta-testing scenario to achieve learning to quickly adapt. In our C-GCD case, the online continual class discovery tasks can be viewed as the \"meta-testing\" stage. Therefore, we propose to simulate the continual setting using \\( S^0 \\) during offline training, as shown in Fig. 2 (b). We aim to produce a model initialization that is trained by aligning the training and evaluation objectives so that it is endowed with the capability to effectively discover novel classes with less forgetting during evaluation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.601, + 0.895, + 0.868 + ], + "angle": 0, + "content": "Sequential task sampling. To mimic the evaluation process, we sample sequential learning tasks from \\(\\mathcal{S}^0\\) [7]. Specifically, we first randomly separate the \\(S^0\\) into pseudo labeled and pseudo unlabeled classes without overlapping. Next, we sample a sequence of \\(T + 1\\) sessions, \\(\\mathcal{D} = \\{(\\mathcal{D}_{tr}^j,\\mathcal{D}_{te}^j)\\}_{j = 0}^T\\), where \\(\\mathcal{D}_{tr}^j\\) and \\(\\mathcal{D}_{te}^j\\) are the training and test set for the \\(j^{th}\\) session. For the training splits \\(\\{\\mathcal{D}_{tr}^j\\}\\), we follow the evaluation protocol to only allow the first session to contain labeled data, (i.e., \\(\\mathcal{D}_{tr}^0 = \\{\\mathbf{x}_{tr}^0,\\mathbf{y}_{tr}^0\\}\\)) and the rest with unlabeled data (i.e., \\(\\mathcal{D}_{tr}^j = \\{\\mathbf{x}_{tr}^j\\}\\), for \\(j > 0\\)). We also set the first session to contain a larger number of samples, i.e., \\(\\left|\\mathcal{D}_{tr}^0\\right| \\gg \\left|\\mathcal{D}_{tr}^{j > 0}\\right|\\) to simulate the C-GCD setting where the model is first trained during an offline training stage with a large amount of data. For the test splits \\(\\{\\mathcal{D}_{te}^j\\}\\), all of them contain labels that will be used during the optimization (i.e., \\(\\mathcal{D}_{te}^j = \\{\\mathbf{x}_{te}^j,\\mathbf{y}_{te}^j\\}, \\forall j\\)). Note that \\(\\mathcal{D}_{te}^j\\) only contains the test data belonging to the current session \\(j\\)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.871, + 0.894, + 0.902 + ], + "angle": 0, + "content": "Meta-training. For each sampled sequence \\(\\mathcal{D}\\), we let the model continually explore the incoming unlabeled data in" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "1659" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.32 + ], + "angle": 0, + "content": "an unsupervised manner. To reduce the forgetting issue due to learning new knowledge, we utilize the bi-level optimization [12, 8, 7] to directly formulate incrementally discovering without forgetting as the meta-objective. The meta-learning procedure is illustrated in Alg. 1 and Fig. 2 (b). Concretely, we decouple the network as \\(\\theta = \\{\\theta^{E},\\theta^{P}\\}\\), where \\(\\theta^{E}\\) and \\(\\theta^{P}\\) are the encoder and projection layers. At each incremental session, we aim to evaluate all the classes that have encountered so far. Hence, at the beginning of each sequence, we define an empty cumulative pseudo test set \\(\\mathcal{P}\\) to store the test samples from previous sessions. After that, we first train \\(\\theta\\) on the pseudo labeled classes \\((j = 0)\\) using the unsupervised and supervised contrastive loss (Eq. 3). At each \\(j^{th}\\) session \\((j > 0)\\), we update \\(\\theta\\) on unlabeled samples \\(\\mathcal{D}_{tr}^{j} = \\{\\mathbf{x}_{tr}^{j}\\}\\) via a few gradient steps:" + }, + { + "type": "equation", + "bbox": [ + 0.146, + 0.33, + 0.47, + 0.35 + ], + "angle": 0, + "content": "\\[\n\\tilde {\\theta} ^ {E, P} = \\theta^ {E, P} - \\alpha \\nabla_ {\\theta^ {E, P}} \\mathcal {L} _ {s o f t} (\\mathbf {x} _ {t r} ^ {j}; \\theta) \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.362, + 0.47, + 0.437 + ], + "angle": 0, + "content": "where \\(\\mathcal{L}_{soft}(\\cdot)\\) is the proposed soft neighborhood contrastive loss (Eq. 4). It aims to discriminate uncorrelated samples while absorbing correlated ones. By thoroughly exploring the unlabeled data, it maintains comprehensive old knowledge while efficiently discovering novel classes." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.439, + 0.47, + 0.56 + ], + "angle": 0, + "content": "Eq. 7 mimics how the model discovers novel classes on the incoming unlabeled data at test-time. Ideally, we like the adapted \\(\\tilde{\\theta}^{E,P}\\) to perform well on all encountered classes. The test data from previous sessions and the current session separately reflect the catastrophic forgetting robustness and novel class discovery capability. Thus, we append \\(\\mathcal{D}_{te}^{j}\\) to \\(\\mathcal{P}\\). Accordingly, the meta-objective is defined as follows for the outer loop of the meta-level optimization:" + }, + { + "type": "equation", + "bbox": [ + 0.146, + 0.573, + 0.47, + 0.599 + ], + "angle": 0, + "content": "\\[\n\\min _ {\\theta^ {E}, \\theta^ {P}} \\sum_ {(\\mathcal {X}, \\mathcal {Y}) \\in \\mathcal {P}} \\mathcal {L} _ {s c l} (\\mathcal {X}, \\mathcal {Y}; \\tilde {\\theta} ^ {E}, \\tilde {\\theta} ^ {P}) \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.613, + 0.47, + 0.734 + ], + "angle": 0, + "content": "where \\(\\mathcal{L}_{scl}(\\cdot)\\) is the supervised contrastive loss in Eq. 1. Note that the optimization is performed on \\(\\theta\\), although \\(\\mathcal{L}_{scl}(\\cdot)\\) is a function of \\(\\tilde{\\theta}^E\\) and \\(\\tilde{\\theta}^P\\). The meta-objective in Eq. 8 is then optimized using gradient descent, as shown in Line 13 of Alg. 1. We empty \\(\\mathcal{P}\\) when all \\(T + 1\\) sessions are iterated. After meta-training, we obtain an initialization of the model \\(\\theta\\) which has been specifically trained to discover and learn novel objects from a sequence of unlabeled data." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Meta-testing. It is worth mentioning that the procedure in Alg. 1 aligns with the evaluation protocol. After discovering novel classes at each incremental session, the model is evaluated on all encountered classes. Our meta-objective optimizes the model towards what it is supposed to do at evaluation to maximize the performance. In addition, despite some uncertainties that may occur for unsupervised learning, the model is constrained by a fully supervised meta-objective. Thus, when training converges, the meta-model \\(\\theta\\) is ready to discover novel classes while maintaining the old knowledge by only running Line 10 of Alg. 1." + }, + { + "type": "table", + "bbox": [ + 0.511, + 0.09, + 0.885, + 0.176 + ], + "angle": 0, + "content": "
DatasetLabeled SetUnlabeled Set
#class#image#class#image
CIFAR107280001022000
CIFAR100803200010018000
Tiny-ImageNet1506000020040000
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.186, + 0.894, + 0.232 + ], + "angle": 0, + "content": "Table 1: Datasets used in our experiments. We show the number of classes in the labeled and unlabeled sets, as well as the number of samples." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.257, + 0.634, + 0.274 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.281, + 0.673, + 0.297 + ], + "angle": 0, + "content": "4.1. Dataset and setup" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.304, + 0.892, + 0.44 + ], + "angle": 0, + "content": "Dataset. We construct the C-GCD benchmark using three widely used datasets as in NCD [40, 35, 47], i.e., CIFAR10 [23], CIFAR100 [23] and Tiny-ImageNet [25]. Each dataset is split into two subsets, 1) large-scale labeled samples accounting for \\(80\\%\\) of the known classes data constitute a labeled set for offline training; and 2) the remaining data containing known and novel classes are used as an unlabeled set for continual object discovery. In Tab. 1, we summarize the dataset splits used in our training." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.44, + 0.893, + 0.651 + ], + "angle": 0, + "content": "Session-wise data split. All labeled samples \\( S^0 \\) are used for offline training in our setting. During the online incremental learning stage, the unlabeled samples are dynamically added (i.e., sessions \\( t \\geq 1 \\)). Specifically, CIFAR10 is divided into 3 incremental sessions. In the \\( t^{th}(t > 0) \\) session, 3000 unlabeled images from 1 novel class and 2000 unlabeled images from \\( 7 + (t - 1) \\times 1 \\) known classes are added. CIFAR100 is divided into 4 sessions, in which 1500 unlabeled images from 5 novel classes and 2000 unlabeled images from \\( 80 + (t - 1) \\times 5 \\) known classes are added in the \\( t^{th} \\) session. The Tiny-ImageNet consists of 5 incremental sessions, each containing 3000 unlabeled images from 10 novel classes and 3000 unlabeled images from \\( 150 + (t - 1) \\times 10 \\) known classes." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.652, + 0.894, + 0.802 + ], + "angle": 0, + "content": "Sequential task sampling. During offline training, we use \\( S^0 \\) to sample sequential tasks. We first split \\( S^0 \\) into non-overlapping pseudo labeled and novel classes (4/3 for CIFAR10, 60/20 for CIFAR100 and 100/50 for TinyImageNet). For each task, the pseudo labeled set is first used to warm up the model, followed by \\( T \\) incremental sessions of unlabeled samples containing the pseudo labeled and novel classes. Both the session number and the number of novel classes in each offline incremental session are consistent with the online incremental learning scenario." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.803, + 0.894, + 0.864 + ], + "angle": 0, + "content": "Evaluation metrics. After learning the model on unlabeled samples at every online incremental stage, we follow [40] to measure the clustering accuracy between the ground truth labels \\( y_{i} \\) and the model's predictions \\( \\hat{y}_{i} \\) as:" + }, + { + "type": "equation", + "bbox": [ + 0.56, + 0.872, + 0.892, + 0.904 + ], + "angle": 0, + "content": "\\[\nA C C = \\max _ {p \\in \\mathcal {P} (\\mathcal {Y})} \\frac {1}{N} \\sum \\left(\\mathbb {1} \\left\\{y _ {i} = p \\left(\\hat {y} _ {i}\\right) \\right\\}\\right), \\tag {9}\n\\]" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "1660" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.089, + 0.891, + 0.453 + ], + "angle": 0, + "content": "
MethodsCIFAR10 (Session Number)Final\nImpro.
123
AllOldNewAllOldNewAllOldNewAllOldNewAllOldNew
RankStats69.3170.2058.6365.2367.8651.2038.1650.0135.94+54.50+47.22+48.77
FRoST73.9281.1766.4569.5679.7358.0467.7370.8451.13+24.93+26.39+33.58
VanillaGCD89.2497.9781.8085.1396.6774.6086.4195.0376.75+6.25+2.20+7.96
GM90.0098.4177.4087.3999.0173.4687.8697.1578.93+4.80+0.08+5.78
MetaGCD(ours)95.3899.0789.1593.3498.8185.3992.6697.2384.71
MethodsCIFAR100 (Session Number)Final\nImpro.
1234
AllOldNewAllOldNewAllOldNewAllOldNewAllOldNew
RankStats62.3364.2231.6055.0158.5526.8551.7756.7025.4747.5154.5917.20+27.05+23.01+43.93
FRoST67.1468.5750.7367.0168.8252.6062.3565.4845.6755.8459.0642.95+18.72+18.54+18.18
VanillaGCD76.7877.9158.6073.6775.2960.7072.7774.7262.3371.4474.7558.20+3.12+2.85+2.93
GM78.2979.9166.0077.5879.6461.1374.5677.6058.1472.0275.9856.32+2.54+1.62+4.81
MetaGCD(ours)78.9679.3672.6078.6779.4166.8176.0678.2064.8774.5677.6061.13
MethodsTiny-ImageNet (Session Number)Final\nImpro.
1234
AllOldNewAllOldNewAllOldNewAllOldNewAllOldNew
RankStats62.3964.5435.0155.8952.2334.2049.8846.1728.3344.2042.8724.5036.0935.2015.76
FRoST64.9267.8446.2859.5061.8640.6057.8660.6339.1455.6859.7136.5550.4953.7633.37
VanillaGCD75.9278.1762.1574.5377.7356.1273.6474.8557.3170.6971.1354.3566.1567.1754.43
GM76.3279.5563.6075.4378.1057.4072.6376.2954.8070.5476.8051.5067.3172.0850.90
MetaGCD(ours)78.6779.4166.8077.8979.9561.4075.2377.8661.2072.0075.6157.5570.2471.5358.46
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.464, + 0.893, + 0.496 + ], + "angle": 0, + "content": "Table 2: Performance (in %) comparisons with the state-of-the-art methods on CIFAR10, CIFAR100, Tiny-ImageNet datasets. The results of other methods are obtained by running their released codes under the C-GCD setting." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.522, + 0.471, + 0.675 + ], + "angle": 0, + "content": "where \\(N\\) is the total number of test samples and \\(\\mathcal{P}(\\mathcal{V})\\) is the set of all permutations of the class labels \\(\\mathcal{V}\\) encountered so far. The optimal permutation can be obtained via the Hungarian algorithm [24]. Our main metric is ACC on 'All' classes, indicating the accuracy across all accumulated test sets so far. To decouple the evaluation on forgetting and discovery, we further report accuracy for both the 'Old' classes subset (samples in the test set belonging to previous known classes) and 'New' classes subset (samples in the test set belonging to novel classes)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.689, + 0.472, + 0.903 + ], + "angle": 0, + "content": "Implementation details. Following [40], we employ a vision transformer (ViT-B-16) [10] pretrained on ImageNet [9] with DINO [3] as the feature extractor throughout the paper. We use the Adam optimizer and the learning rates in Alg. 1 are set as \\(\\gamma = 0.1\\), \\(\\alpha = 0.001\\) and \\(\\beta = 0.0001\\). We use a batch size of 256 and \\(\\lambda = 0.35\\) to balance the losses in Eq. 3. Unless otherwise stated, we select the threshold \\(\\epsilon\\) to be 0.85 in Eq. 5. At the meta-training stage, we first perform training on pseudo labeled set for 50 epochs, followed by 10 inner and 1 outer gradient updates for incremental sessions. At the meta-test stage, we directly perform 20 gradient updates to adapt using unlabeled samples. Furthermore, we follow standard practice in self-supervised learning to use the same projection head as in [3] and discard it at test-time." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.521, + 0.819, + 0.538 + ], + "angle": 0, + "content": "4.2. Comparison with the state-of-the-art" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.549, + 0.892, + 0.777 + ], + "angle": 0, + "content": "Since this paper considers a new problem setting, there is no prior work that we can directly compare. Nevertheless, we choose SOTA methods on NCD and run their codes under our C-GCD setting, including RankStats [16], VanillaGCD [40], and recent continual NCD models FRoST [35], GM [45]. Both RankStats and FRoST train two classifiers on top of a shared feature representation. The first head is fed images from the labeled set and is trained with the cross-entropy loss, while the second head sees only images from unlabeled images of novel classes. In order to adapt RankStats and FRoST to C-GCD, we train them with a single classification head for the total number of classes in the dataset. The sequential version of VanillaGCD is adopted and serves as the baseline for our model. We leverage the original training mechanism for GM." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.78, + 0.893, + 0.903 + ], + "angle": 0, + "content": "In Tab. 2, we report the All/Old/New class accuracy per incremental session for all methods, and the relative improvement for the final session. As we can see, the proposed method consistently outperforms all other methods on all three datasets among the most incremental sessions. Specifically, our MetaGCD surpasses the most recent method GM by \\(5.78\\%\\), \\(4.81\\%\\) and \\(7.56\\%\\) on CIFAR10, CIFAR100 and Tiny-ImageNet datasets for the final New classes accuracy." + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.514, + 0.958 + ], + "angle": 0, + "content": "1661" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.082, + 0.09, + 0.891, + 0.206 + ], + "angle": 0, + "content": "
MethodsCIFAR100 (Session Number)Average Acc
1234
AllOldNewAllOldNewAllOldNewAllOldNewmAmOmN
Baseline76.7877.9158.6073.6775.2960.7072.7774.6262.3371.4474.7558.2073.6775.6459.96
+LCN77.2978.5365.4475.2077.6763.0874.5575.9163.6372.6275.4359.4074.9276.8962.89
+LSP77.9278.4568.7876.5378.2264.7174.8677.2464.0973.3476.8760.6075.6677.7064.55
+Meta-learning78.9679.3672.6078.6779.4166.8176.0678.2064.8774.5677.6061.1377.0678.6466.35
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.217, + 0.893, + 0.263 + ], + "angle": 0, + "content": "Table 3: Ablation study of various components of our MetaGCD on the CIFAR100 dataset. We report 'All', 'Old' and 'New' class accuracy for each incremental session, and the average of all sessions such as mean 'All' (mA), mean 'Old' (mO) and mean 'New' accuracy (mN). Here CN denotes candidate neighbors and SP denotes soft positiveness." + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.301, + 0.268, + 0.441 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.274, + 0.302, + 0.468, + 0.441 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.454, + 0.47, + 0.545 + ], + "angle": 0, + "content": "Figure 3: Class-wise performance on the CIFAR100 dataset. The confusion matrices show that our model significantly improves the baseline for both known and novel classes (separated by the red line). Especially for novel classes, the confusion matrix of our method has more concentrated values along the diagonal." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.575, + 0.47, + 0.696 + ], + "angle": 0, + "content": "Besides, our model outperforms the baseline VanillaGCD by \\(6.25\\%\\), \\(3.12\\%\\) and \\(4.09\\%\\) for the final All classes. We also report the class-wise performance via the confusion matrices shown in Fig. 3. It is obvious that the baseline performs poorly, especially on the novel classes. However, the proposed model has a significant gain in discovering novel classes. Moreover, less forgetting is observed in our method, as more values are concentrated on the diagonal." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.709, + 0.231, + 0.725 + ], + "angle": 0, + "content": "4.3. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.733, + 0.469, + 0.763 + ], + "angle": 0, + "content": "We conduct ablation studies on the CIFAR100 dataset to evaluate each component in our proposed framework." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Importance of neighborhood. In our contrastive learning framework, we compute the soft correlation to allow more positive pairs to contribute to the loss. As reported in the second row of Tab. 3, considering the neighborhood achieves a performance gain of \\(1.25\\%\\) (i.e., \\(74.92\\%\\) v.s. \\(73.67\\%\\) on the mean accuracy of All classes). The performance gain may come from the abundant comparisons from positive samples, which facilitates the current instance to align with more highly-correlated samples. We also conduct" + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.299, + 0.885, + 0.389 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.4, + 0.893, + 0.476 + ], + "angle": 0, + "content": "Figure 4: Hyper-parameter analysis on the CIFAR100 dataset regarding feature similarity threshold (left) and various numbers of novel classes (right). An appropriate threshold or the number of new classes helps to stabilize the training process and improve performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.506, + 0.892, + 0.627 + ], + "angle": 0, + "content": "experiments to assess the sensitivity of threshold \\(\\epsilon\\) when selecting the positive neighbor instances. Increasing \\(\\epsilon\\) allows more strict positive pairs, but some partially related samples might be ignored. On the other hand, reducing \\(\\epsilon\\) increases the likelihood of introducing true negative samples, which may negatively impact model performance. As empirically found in the left side of Fig. 4, a trade-off should be made, and a threshold of 0.85 achieves the best performance." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.628, + 0.893, + 0.854 + ], + "angle": 0, + "content": "Importance of soft positiveness. We then analyze the importance of soft positiveness to the recognition performance in the third row of Tab. 3. When we compute a correlation weight for each selected neighbor, the clustering accuracy on Novel classes increases from \\(62.89\\%\\) to \\(64.55\\%\\). It indicates that the binary labeling strategy is insufficient to measure the correlation at the feature space, thus causing the backbone network to produce less discriminative representations compared with soft labeling methods. In the lower part of Fig. 2 (a), we show the correlation weight of selected neighbors with an input instance. The high score corresponds to the same category while the low score corresponds to less-correlated categories, which shows that our attention module is effective in modeling correlations between the input instance and each candidate neighbor." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.856, + 0.892, + 0.9 + ], + "angle": 0, + "content": "Effectiveness of meta-learning. Our meta-learning optimization strategy further improves All classes accuracy to \\(74.56\\%\\) for the final incremental session in the last row" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "1662" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.259 + ], + "angle": 0, + "content": "of Tab. 3. It demonstrates the effectiveness of the proposed method where the meta-objective specifically forces the model to discover novel classes without forgetting old classes. Additionally, we analyze the impact of the number of novel classes that are sampled during meta-training. To investigate this, we train separate models by setting the number of novel classes in the range of \\(\\{1, 10\\}\\). As illustrated on the right side of Fig. 4, a larger number of classes for sequence tasks is more optimal. When there are fewer classes, the model is at a higher risk of overfitting to certain classes rather than learning how to incrementally learn." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.272, + 0.196, + 0.287 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.298, + 0.473, + 0.465 + ], + "angle": 0, + "content": "In this paper, we propose a more realistic setting for real-world applications, namely C-GCD. The ultimate goal of C-GCD is to discover novel classes while keeping the old knowledge without forgetting. We propose a meta-learning based optimization strategy to directly optimize the network to learn how to incrementally discover with less forgetting. In addition, we introduce a soft neighborhood contrastive learning to utilize the soft positiveness to adaptively support the current instances from their neighbors. Extensive experiments on three datasets demonstrate the superiority of our method over state-of-the-art methods." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.478, + 0.258, + 0.495 + ], + "angle": 0, + "content": "6. Acknowledgments" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.503, + 0.47, + 0.565 + ], + "angle": 0, + "content": "This work was supported by the Fundamental Research Funds for the Central Universities (No. 2022JBZY019), the National Key Research and Development Project (No. 2018AAA0100300) and an NSERC Discovery grant." + }, + { + "type": "title", + "bbox": [ + 0.08, + 0.578, + 0.175, + 0.594 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.603, + 0.47, + 0.658 + ], + "angle": 0, + "content": "[1] Philip Bachman, R Devon Hjelm, and William Buchwalter. Learning representations by maximizing mutual information across views. Advances in Neural Information Processing Systems, 32, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.66, + 0.47, + 0.715 + ], + "angle": 0, + "content": "[2] Peyman Bateni, Raghav Goyal, Vaden Masrani, Frank Wood, and Leonid Sigal. Improved few-shot visual classification. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 14493-14502, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.717, + 0.471, + 0.785 + ], + "angle": 0, + "content": "[3] Mathilde Caron, Hugo Touvron, Ishan Misra, Hervé Jégou, Julien Mairal, Piotr Bojanowski, and Armand Joulin. Emerging properties in self-supervised vision transformers. In Proceedings of the IEEE International Conference on Computer Vision, pages 9650-9660, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.788, + 0.47, + 0.829 + ], + "angle": 0, + "content": "[4] Can Chen, Yingxueff Zhang, Jie Fu, Xue Steve Liu, and Mark Coates. Bidirectional learning for offline infinite-width model-based optimization. NeurIPS, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.831, + 0.47, + 0.872 + ], + "angle": 0, + "content": "[5] Can Chen, Shuhao Zheng, Xi Chen, Erqun Dong, Xue Steve Liu, Hao Liu, and Dejing Dou. Generalized dataweighting via class-level gradient manipulation. NeurIPS, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.874, + 0.47, + 0.902 + ], + "angle": 0, + "content": "[6] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning" + }, + { + "type": "list", + "bbox": [ + 0.087, + 0.603, + 0.471, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "of visual representations. In Proceedings of the IEEE International Conference on Machine Learning, pages 1597-1607, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.135, + 0.894, + 0.204 + ], + "angle": 0, + "content": "[7] Zhixiang Chi, Li Gu, Huan Liu, Yang Wang, Yuanhao Yu, and Jin Tang. Meta-scl: A meta-learning approach for few-shot class incremental learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 14166-14175, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.205, + 0.892, + 0.272 + ], + "angle": 0, + "content": "[8] Zhixiang Chi, Yang Wang, Yuanhao Yu, and Jin Tang. Test-time fast adaptation for dynamic scene deblurring via meta-auxiliary learning. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9137-9146, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.51, + 0.274, + 0.892, + 0.33 + ], + "angle": 0, + "content": "[9] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 248-255, 2009." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.33, + 0.894, + 0.426 + ], + "angle": 0, + "content": "[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In Proceedings of the IEEE International Conference on Learning Representations, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.428, + 0.892, + 0.495 + ], + "angle": 0, + "content": "[11] Enrico Fini, Enver Sangineto, Stéphane Lathuilière, Zhun Zhong, Moin Nabi, and Elisa Ricci. A unified objective for novel class discovery. In Proceedings of the IEEE International Conference on Computer Vision, pages 9284-9292, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.497, + 0.892, + 0.552 + ], + "angle": 0, + "content": "[12] Chelsea Finn, Pieter Abbeel, and Sergey Levine. Model-agnostic meta-learning for fast adaptation of deep networks. In Proceedings of International Conference on Machine Learning, pages 1126–1135, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.553, + 0.892, + 0.607 + ], + "angle": 0, + "content": "[13] Li Gu, Zhixiang Chi, Huan Liu, Yuanhao Yu, and Yang Wang. Improving protonet for few-shot video object recognition: Winner of orbit challenge 2022. arXiv preprint arXiv:2210.00174, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.609, + 0.892, + 0.676 + ], + "angle": 0, + "content": "[14] Michael Gutmann and Aapo Hyvarinen. Noise-contrastive estimation: A new estimation principle for unnormalized statistical models. In Proceedings of the International Conference on Artificial Intelligence and Statistics, pages 297–304, 2010." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.679, + 0.892, + 0.747 + ], + "angle": 0, + "content": "[15] Kai Han, Sylvestre-Alvise Rebuffi, Sebastien Ehrhardt, Andrea Vedaldi, and Andrew Zisserman. Automatically discovering and learning new visual categories with ranking statistics. In International Conference on Learning Representations, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.749, + 0.892, + 0.816 + ], + "angle": 0, + "content": "[16] Kai Han, Sylvestre-Alvise Rebuffi, Sebastien Ehrhardt, Andrea Vedaldi, and Andrew Zisserman. Autonovel: Automatically discovering and learning novel visual categories. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(10):6767-6781, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.818, + 0.892, + 0.872 + ], + "angle": 0, + "content": "[17] Kai Han, Andrea Vedaldi, and Andrew Zisserman. Learning to discover novel visual categories via deep transfer clustering. In Proceedings of the IEEE International Conference on Computer Vision, pages 8401-8409, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.874, + 0.892, + 0.902 + ], + "angle": 0, + "content": "[18] Kaiming He, Haoqi Fan, Yuxin Wu, Saining Xie, and Ross Girshick. Momentum contrast for unsupervised visual rep" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.894, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "1663" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.133 + ], + "angle": 0, + "content": "resentation learning. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 9729-9738, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.134, + 0.47, + 0.189 + ], + "angle": 0, + "content": "[19] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.19, + 0.469, + 0.232 + ], + "angle": 0, + "content": "[20] Khurram Javed and Martha White. Meta-learning representations for continual learning. Advances in Neural Information Processing Systems, 32, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.233, + 0.471, + 0.3 + ], + "angle": 0, + "content": "[21] KJ Joseph, Sujoy Paul, Gaurav Aggarwal, Soma Biswas, Piyush Rai, Kai Han, and Vineeth N Balasubramanian. Novel class discovery without forgetting. In Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 570-586, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.302, + 0.469, + 0.37 + ], + "angle": 0, + "content": "[22] Prannay Khosla, Piotr Teterwak, Chen Wang, Aaron Sarna, Yonglong Tian, Phillip Isola, Aaron Maschinot, Ce Liu, and Dilip Krishnan. Supervised contrastive learning. Advances in Neural Information Processing Systems, 33:18661-18673, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.371, + 0.469, + 0.412 + ], + "angle": 0, + "content": "[23] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images. Handbook of Systemic Autoimmune Diseases, 1(4), 2009." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.413, + 0.469, + 0.453 + ], + "angle": 0, + "content": "[24] Harold W Kuhn. The hungarian method for the assignment problem. Naval Research Logistics Quarterly, 2(1-2):83-97, 1955." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.455, + 0.469, + 0.482 + ], + "angle": 0, + "content": "[25] Ya Le and Xuan Yang. Tiny imagenet visual recognition challenge. CS 231N, 7(7):3, 2015." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.484, + 0.469, + 0.524 + ], + "angle": 0, + "content": "[26] Zhizhong Li and Derek Hoiem. Learning without forgetting. IEEE Transactions on Pattern Analysis and Machine Intelligence, 40(12):2935-2947, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.525, + 0.469, + 0.594 + ], + "angle": 0, + "content": "[27] Hanwen Liang, Niamul Quader, Zhixiang Chi, Lizhe Chen, Peng Dai, Juwei Lu, and Yang Wang. Self-supervised spatiotemporal representation learning by exploiting video continuity. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 1564-1573, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.595, + 0.469, + 0.662 + ], + "angle": 0, + "content": "[28] Huan Liu, Zhixiang Chi, Yuanhao Yu, Yang Wang, Jun Chen, and Jin Tang. Meta-auxiliary learning for future depth prediction in videos. In Proceedings of the IEEE Winter Conference on Applications of Computer Vision, pages 5756-5765, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.664, + 0.469, + 0.733 + ], + "angle": 0, + "content": "[29] Huan Liu, Li Gu, Zhixiang Chi, Yang Wang, Yuanhao Yu, Jun Chen, and Jin Tang. Few-shot class-incremental learning via entropy-regularized data-free replay. In Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 146–162, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.734, + 0.469, + 0.803 + ], + "angle": 0, + "content": "[30] Huan Liu, Zijun Wu, Liangyan Li, Sadaf Salehkalaibar, Jun Chen, and Keyan Wang. Towards multi-domain single image dehazing via test-time training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5831-5840, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.804, + 0.469, + 0.871 + ], + "angle": 0, + "content": "[31] Yaoyao Liu, Yuting Su, An-An Liu, Bernt Schiele, and Qianru Sun. Mnemonics training: Multi-class incremental learning without forgetting. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 12245–12254, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.872, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[32] Yiwei Lu, Frank Yu, Mahesh Kumar Krishna Reddy, and Yang Wang. Few-shot scene-adaptive anomaly detection. In" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 125-141, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.122, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[33] Tian Pan, Yibing Song, Tianyu Yang, Wenhao Jiang, and Wei Liu. Videomoco: Contrastive video representation learning with temporally adversarial examples. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 11205-11214, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.192, + 0.892, + 0.234 + ], + "angle": 0, + "content": "[34] Sachin Ravi and Hugo Larochelle. Optimization as a model for few-shot learning. In International Conference on Learning Representations, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.235, + 0.892, + 0.291 + ], + "angle": 0, + "content": "[35] Subhankar Roy, Mingxuan Liu, Zhun Zhong, Nicu Sebe, and Elisa Ricci. Class-incremental novel class discovery. In Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 317-333, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.293, + 0.892, + 0.347 + ], + "angle": 0, + "content": "[36] Adam Santoro, Sergey Bartunov, Matthew Botvinick, Daan Wierstra, and Timothy Lillicrap. Meta-learning with memory-augmented neural networks. In International Conference on Machine Learning, pages 1842-1850, 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.349, + 0.892, + 0.391 + ], + "angle": 0, + "content": "[37] Karen Simonyan and Andrew Zisserman. Very deep convolutional networks for large-scale image recognition. In International Conference on Learning Representations, 2014." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.392, + 0.892, + 0.433 + ], + "angle": 0, + "content": "[38] Jake Snell, Kevin Swersky, and Richard Zemel. Prototypical networks for few-shot learning. Advances in Neural Information Processing Systems, 30, 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.435, + 0.892, + 0.49 + ], + "angle": 0, + "content": "[39] Jae Woong Soh, Sunwoo Cho, and Nam Ik Cho. Meta-transfer learning for zero-shot super-resolution. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 3516-3525, 2020." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.492, + 0.892, + 0.547 + ], + "angle": 0, + "content": "[40] Sagar Vaze, Kai Han, Andrea Vedaldi, and Andrew Zisserman. Generalized category discovery. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 7492-7501, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.549, + 0.892, + 0.616 + ], + "angle": 0, + "content": "[41] Yue Wu, Yinpeng Chen, Lijuan Wang, Yuancheng Ye, Zicheng Liu, Yandong Guo, and Yun Fu. Large scale incremental learning. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 374-382, 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.619, + 0.892, + 0.689 + ], + "angle": 0, + "content": "[42] Yanan Wu, Tengfei Liang, Songhe Feng, Yi Jin, Gengyu Lyu, Haojun Fei, and Yang Wang. Metazscil: A meta-learning approach for generalized zero-shot class incremental learning. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 37, pages 10408-10416, 2023." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.69, + 0.892, + 0.758 + ], + "angle": 0, + "content": "[43] Chi Zhang, Nan Song, Guosheng Lin, Yun Zheng, Pan Pan, and Yinghui Xu. Few-shot incremental learning with continually evolved classifiers. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 12455–12464, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.761, + 0.892, + 0.829 + ], + "angle": 0, + "content": "[44] Marvin Zhang, Henrik Marklund, Nikita Dhawan, Abhishek Gupta, Sergey Levine, and Chelsea Finn. Adaptive risk minimization: Learning to adapt to domain shift. Advances in Neural Information Processing Systems, 34:23664-23678, 2021." + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.831, + 0.892, + 0.9 + ], + "angle": 0, + "content": "[45] Xinwei Zhang, Jianwen Jiang, Yutong Feng, Zhi-Fan Wu, Xibin Zhao, Hai Wan, Mingqian Tang, Rong Jin, and Yue Gao. Grow and merge: A unified framework for continuous categories discovery. Advances in Neural Information Processing Systems, 2022." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "1664" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.079, + 0.092, + 0.47, + 0.147 + ], + "angle": 0, + "content": "[46] Tao Zhong, Zhixiang Chi, Li Gu, Yang Wang, Yuanhao Yu, and Jin Tang. Meta-dmoe: Adapting to domain shift by metadata distillation from mixture-of-experts. Advances in Neural Information Processing Systems, 35:22243-22257, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.15, + 0.468, + 0.219 + ], + "angle": 0, + "content": "[47] Zhun Zhong, Enrico Fini, Subhankar Roy, Zhiming Luo, Elisa Ricci, and Nicu Sebe. Neighborhood contrastive learning for novel class discovery. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 10867-10875, 2021." + }, + { + "type": "list", + "bbox": [ + 0.079, + 0.092, + 0.47, + 0.219 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.485, + 0.946, + 0.515, + 0.956 + ], + "angle": 0, + "content": "1665" + } + ] +] \ No newline at end of file diff --git a/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/991c02f6-2cc1-4391-a19c-b8559690aace_origin.pdf b/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/991c02f6-2cc1-4391-a19c-b8559690aace_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..9ca90b1c77283bdf3aaf264d023cc6e3c98a6a51 --- /dev/null +++ b/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/991c02f6-2cc1-4391-a19c-b8559690aace_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:343b25f109c09ddfdcb585d22604ad8b0b8a83f732c7d4bdb79e9a9a49c475a6 +size 1922776 diff --git a/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/full.md b/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/full.md new file mode 100644 index 0000000000000000000000000000000000000000..8a77c5e9b191f7723c48e9c4faa9c7879f81acec --- /dev/null +++ b/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/full.md @@ -0,0 +1,300 @@ +# MetaGCD: Learning to Continually Learn in Generalized Category Discovery + +Yanan Wu $^{1,2*}$ , Zhixiang Chi $^{3*}$ , Yang Wang $^{4}$ , Songhe Feng $^{1,2\dagger}$ + +1Key Laboratory of Big Data & Artificial Intelligence in Transportation, Ministry of Education, Beijing Jiaotong University, Beijing, 100044, China + +$^{2}$ School of Computer and Information Technology, Beijing Jiaotong University, Beijing, 100044, China + $^{3}$ Department of Electrical and Computer Engineering, University of Toronto, Toronto, M5G1V7, Canada + $^{4}$ Department of Computer Science and Software Engineering, Concordia University, Montreal, H3G2J1, Canada + +{ynwu0510,shfeng}@bjtu.edu.cn,zhixiang.chi@mail.utoronto.ca,yang.wang@concordia.ca + +# Abstract + +In this paper, we consider a real-world scenario where a model that is trained on pre-defined classes continually encounters unlabeled data that contains both known and novel classes. The goal is to continually discover novel classes while maintaining the performance in known classes. We name the setting Continual Generalized Category Discovery (C-GCD). Existing methods for novel class discovery cannot directly handle the C-GCD setting due to some unrealistic assumptions, such as the unlabeled data only containing novel classes. Furthermore, they fail to discover novel classes in a continual fashion. In this work, we lift all these assumptions and propose an approach, called MetaGCD, to learn how to incrementally discover with less forgetting. Our proposed method uses a meta-learning framework and leverages the offline labeled data to simulate the testing incremental learning process. A meta-objective is defined to revolve around two conflicting learning objectives to achieve novel class discovery without forgetting. Furthermore, a soft neighborhood-based contrastive network is proposed to discriminate uncorrelated images while attracting correlated images. We build strong baselines and conduct extensive experiments on three widely used benchmarks to demonstrate the superiority of our method. + +# 1. Introduction + +Object categories in real-world environments are dynamically evolving and expanding over time. However, conventional deep learning-based visual recognition methods normally focus on closed-world scenarios with pre-defined categories [19, 37]. Such systems are brittle when deployed to + +![](images/077eab0066f1e2e63bd1cb6c52b242d4b07a55a192300dd264147b6651586117.jpg) +Figure 1: Illustration of our C-GCD setting. During the offline training, we learn an initial model based on training samples of the labeled set. During each subsequent online incremental learning, we are given some unlabeled images belonging to both known and novel classes. Our goal is to update the model in each incremental session so that the model can maintain the performance on old classes while discovering novel classes. + +an ever-changing realistic open-world setting, where object instances may come from new categories. In contrast, recognizing the known categories and utilizing them to discern the unknowns are intrinsic to human perception. + +Recently, discovering the novel classes among unlabeled data has been an active area of research [15, 11, 40, 35, 45]. However, most prior works make several assumptions that are unrealistic in practice. For example, the works in [15, 11, 40] assume the co-existence of both labeled data (with known classes) and unlabeled data (contains potential unknown classes to be discovered) at the training phase and + +the models are learned from scratch. This leads to repetitive large-scale training every time when new classes are expected to be discovered. The works in [15, 11, 35, 45] assume the newly encountered unlabeled data only belongs to the novel classes. This is unrealistic in practice. To meet such conditions, a rigorous filtering method is needed to precisely filter out known class data to avoid degenerate solutions. Due to these limitations, none of these works can be used to build recognition systems that can deal with evolving object categories sequentially over a long time horizon. + +In this paper, we consider a more flexible setting for real-world applications. Let us consider the application of home robots. The robots are equipped with an offline trained object recognition model on pre-defined categories during manufacturing. After deployment, the robots are expected to operate in diverse environments. While operating, they continually receive data that belongs to known and possibly unknown classes. Ideally, we would like the robots to continually discover and learn novel classes from such data. We dub such a setting as Continuous Generalized Class Discovery (C-GCD). As shown in Fig. 1, C-GCD has two phases: 1) an offline training phase that allows the model to be trained on large-scale labeled data with pre-defined classes; 2) when the model is deployed, it continually encounters unlabeled data that comes from both known and novel classes on a longer horizon. At each incremental session, the data from the previous sessions is inaccessible. The model needs to precisely classify the known classes and discover novel ones to expand its knowledge base. Obviously, the main challenge of C-GCD is to discover the novel classes among unlabeled images that contain both known and unknown categories while maintaining the performance on old classes. However, learning novel knowledge normally leads to notorious catastrophic forgetting [7], which further exacerbates the model performance. + +There are some initial attempts on C-GCD [21, 45]. However, they only consider C-GCD at the deployment stage mentioned above. The offline training stage is not fully exploited in these works. Concretely, the labeled data during offline training is only used for pre-training model representations. Therefore, the model at the offline stage is unaware of its subsequent learning duty (discover novel classes and retain the performance of known classes) [8] and is also prone to overfit to the labeled set [40]. Such learning objective misalignment leads to cumbersome heuristic strategies to facilitate the new learning task while keeping the previous knowledge. For example, to learn the novel classes, [21] requires a self-labeling method, which may cause error propagation. A routing strategy is also required to determine the known and novel classifier heads. [45] relies on a thresholding method to filter novel instances. However, the overall robustness of the method can be sensitive to the threshold. To alleviate the + +forgetting issues, [21, 45] propose to distill the knowledge from the pre-trained base models. Data replay is also utilized to either directly select representative labeled exemplars [45] or generate pseudo-latent representations from them [21]. Consequently, the base models and the replay buffers have to be stored locally which may cause storage problems, especially in a resource-constraint environment. + +In this work, we propose a fully learning-based solution, named MetaGCD, to minimize the hand-engineered heuristics in prior works. Concretely, at the offline training phase, instead of pre-training a model representation, we directly train an initialization that is learned to discover novel categories with less forgetting when deployed. It is realized by meta-learning-based bi-level optimization [12] to couple the offline training and downstream learning objectives. During the offline training, we simulate the testing scenario and construct pseudo incremental novel class discovery sessions using the labeled data. At each incremental session, we discover novel classes by updating the model using an unsupervised contrastive loss. The meta-objective is then defined by validating the updated model on all classes encountered on a labeled pseudo test set. Therefore, the meta-objective of the offline training is aligned with the evaluation protocol at deployment. It enforces the model to learn to balance two conflicting objectives, namely discovering new objects and not-forgetting old objects. The meta-objective also reinforces the unsupervised updated model to be supervised by the true labels to ensure valid novel class discovery. + +MetaGCD uses unsupervised contrastive learning to explore the relationship among instances for novel class discovery. Therefore, it is less prone to label overfitting [40]. However, we observe that the negative pairs in contrastive learning normally dominate the loss function. So we further propose soft neighborhood contrastive learning to mine more positiveness. Concretely, for each image instance, we select the nearest candidate neighbors within the batch to treat them as soft positive samples to contribute to the discriminative feature learning. Overall, our contributions are summarised as follows: + +- We consider a realistic setting C-GCD for applications in real-world scenarios. It allows the model trained on pre-defined classes to continually explore novel classes through incoming unlabeled data while simultaneously keeping the performance of known classes. +- We propose a meta-learning approach where the learning objective is well aligned with the evaluation protocol during testing. It directly optimizes the model to achieve novel object discovery without forgetting. +- A soft neighborhood contrastive learning method is also proposed to mine more soft positive pairs to elevate the discovery capability. +- We establish strong baselines and show that our method achieves superior performance with less hand + +engineered design through extensive experiments. + +# 2. Related Work + +Discovering novel classes. Novel Class Discovery (NCD) aims to discover the novel classes from unlabeled data by utilizing the prior knowledge from the labeled data [15, 11, 17]. However, NCD assumes that the unlabeled data only belongs to the novel classes, which is unrealistic. Alternatively, a generalized version of NCD (GCD) [40] relaxes such constrain. Although GCD allows the unlabeled data to contain both known and novel classes, they are both required to be present in the training phase. It leads to repetitive large-scale training when different groups of unlabeled data are continually presented to the recognition system. Recently, a class incremental variant of NCD (class-iNCD) is proposed to learn the tasks of labeled known and unlabeled novel classes sequentially [35]. When learning the novel classes, the data of old classes are inaccessible. In the end, the model is evaluated on all encountered classes. Nevertheless, only a few incremental sessions containing unlabeled novel classes are allowed in class-iNCD. This limitation hinders its applicability under the realistic setting with continually evolved object categories. Our proposed C-GCD alleviates the above limitations in real-world scenarios. Our approach can learn from labeled pre-defined classes during offline training, and then continuously encounter unlabeled data with both known and novel classes after deployment. Our model will learn to discover novel classes without forgetting old classes. C-GCD is also related to the classic class-incremental setting [26, 41, 31, 29]. But C-GCD is more challenging as the newly evolved classes are unlabeled and an automatic class discovery mechanism is required [21]. + +Meta-learning. Existing meta-learning methods can be categorized into: 1) model-based [36, 2, 4]; 2) Optimization-based [34, 12, 5]; and 3) metric-based [38]. Typical meta-learning methods utilize bi-level optimization to train a model that is applicable for downstream adaptations. Our work is built upon MAML [12], which trains a model initialization through episodes of tasks for fast adaptation via gradient updates. Such learning paradigm has been widely applied in different vision tasks, such as test-time adaptation [39, 28, 32, 30], continual learning [43, 20, 42] and domain shift [44, 46, 13]. In our case, the adaptation is achieved in an unsupervised manner, and the bi-level optimization is utilized to combine two conflicting learning objectives: discovering the novel classes without forgetting the old classes. + +Contrastive learning. Contrastive learning has been popular in self-supervised visual representation learning [1, 6, 18, 33, 27]. It explores the relationships among data instances by constructing positive and negative pairs. Therefore, the overfitting on the label space is reduced to im + +prove the generalization of downstream tasks. Zhong et al. [47] apply contrastive learning to discover novel classes by exploring the data neighborhood and choosing pseudopositive pairs. However, those pseudo-positive pairs contribute equally regardless of their closeness compared to the reference sample. In this work, we introduce the soft positiveness concept to allow adaptive contribution. + +# 3. The Proposed Method + +Problem definition. The goal of C-GCD is to have the offline trained model continually discover and learn novel object classes from unlabeled data containing both known and novel classes. We define a sequence of $T$ learning sessions $\{S^0, S^1, \dots, S^T\}$ . Let $x^t \in \mathcal{X}^t$ and $y^t \in \mathcal{Y}^t$ denote the input and label space at session $t$ . We represent each session as: $S^0 = \{(\mathbf{x}_i^0, \mathbf{y}_i^0)\}_{i=1}^{Z_0}$ and $S^t = \{(\mathbf{x}_i^t)\}_{i=1}^{Z_t}$ . Note, only the first session (i.e., $t = 0$ ) contains large-scale labeled samples. As for $t > 0$ , $S^t$ only contains unlabeled data. At the $t^{th}$ session, only $S^t$ is accessible, and the incoming data belongs to both learned known class from previous sessions and novel classes. Therefore, we can denote $\mathcal{Y}^t = \mathcal{Y}^{t-1} \cup \mathcal{Y}_n^t$ , where $\mathcal{Y}_n^t$ represents the novel classes to be discovered at session $t$ . After learning on $S^t$ , the model is evaluated on all test images accumulated until session $t$ to test the performance on $\mathcal{Y}^{t-1}$ (ideally the model should not forget old classes) and the discovery capability on $\mathcal{Y}_n^t$ . Compared with previous works [15, 11, 35, 45], C-GCD is much more challenging due to several factors. First, the unlabeled data contains both known and unknown classes, i.e., $\mathcal{Y}^t = \mathcal{Y}^{t-1} \cup \mathcal{Y}_n^t$ . Second, labeled data is absent at $t > 0$ , i.e., $S^0 \cup S^t = \emptyset$ where $t > 0$ . Finally, since C-GCD operates on a long horizon, i.e., $t \gg 1$ , the catastrophic forgetting issue is more severe. + +Method overview. Fig. 2 shows an overview of MetaGCD. Following [40], we use a model without parametric classification heads since it is more suitable for dealing with novel classes. Novel class discovery is performed by directly clustering the feature spaces and class labels are assigned through the classic $k$ -means algorithm. Concretely, we learn a model initialization using the labeled data during offline training. During each continual learning session, we update the model using a soft neighborhood contrastive learning (see Fig. 2 (a)) on unlabeled data. To fully exploit the labeled data in offline learning, we further develop a bilevel optimization based on meta-learning to simulate the online learning scenario, so that the model is ready to adapt to new incoming unlabeled data and discover novel objects after the offline training (see Fig. 2 (b)). In the following, we describe these two parts of our method in detail. + +# 3.1. Contrastive learning based clustering network + +Considering the characteristics of labeled and unlabeled data, we employ different contrastive learning strategies. To + +![](images/9e89f4bcee28c996ca8261db3b804012b7177c25da688e497b7b2acd27352edf.jpg) + +![](images/23015a8311b36a9bf85e73d19f28bb88e2f63c7cbffc3d6cda72c6b0713fc6b0.jpg) +Figure 2: Overview of the proposed MetaGCD. (a) Our soft neighborhood contrastive learning network aims to discriminate uncorrelated instances while absorbing correlated instances to learn discriminative representations. (b) Our meta-learning optimization strategy utilizes the offline labeled data to simulate the testing incremental learning process by sampling sequential learning tasks. By learning from these sampled sequential tasks, our model learns a good initialization, so that it can effectively adapt to discover new novel classes without forgetting old classes. + +train on the labeled data, we utilize a combination of unsupervised and supervised contrastive losses. When discovering the latent classes in continually encountered unlabeled data, we propose to mine soft positive neighbors for each data instance to elevate the discriminative feature learning. + +# 3.1.1 Representation learning on labeled data + +To learn a robust and semantically meaningful representation on labeled data, we utilize both self-supervised [14] and supervised [22] contrastive losses. Let $\mathbf{x}_i$ and $\mathbf{x}_i'$ be two randomly augmented versions of $i^{th}$ instance sample, the unsupervised contrastive loss is expressed as: + +$$ +\mathcal {L} _ {i} ^ {u c l} = - \log \frac {\exp \left(\mathbf {z} _ {i} \cdot \mathbf {z} _ {i} ^ {\prime} / \tau\right)}{\sum_ {n} \mathbb {I} _ {[ n \neq i ]} \exp \left(\mathbf {z} _ {i} \cdot \mathbf {z} _ {n} / \tau\right)} \tag {1} +$$ + +where $\mathbf{z}_i = \phi(f(\mathbf{x}_i))$ , $\mathbb{I}_{[n \neq i]}$ is an indicator function, and $\tau$ is a temperature value. $f$ is the feature extractor, and $\phi$ is a multi-layer perceptron (MLP) projection head. + +The supervised contrastive counterpart is expressed as: + +$$ +\mathcal {L} _ {i} ^ {s c l} = - \frac {1}{| \mathcal {N} (i) |} \sum_ {q \in \mathcal {N} (i)} \log \frac {\exp \left(\mathbf {z} _ {i} \cdot \mathbf {z} _ {q} / \tau\right)}{\sum_ {n} \mathbb {I} _ {[ n \neq i ]} \exp \left(\mathbf {z} _ {i} \cdot \mathbf {z} _ {n} / \tau\right)} \tag {2} +$$ + +where $\mathcal{N}(i)$ denotes the indices of instances having the same label as $\mathbf{x}_i$ within the batch. Finally, these two losses are weighted by $\lambda$ to train on the labeled data: + +$$ +\mathcal {L} _ {\text {l a b e l e d}} = (1 - \lambda) \sum_ {i \in B} \mathcal {L} _ {i} ^ {u c l} + \lambda \sum_ {i \in B} \mathcal {L} _ {i} ^ {s c l} \tag {3} +$$ + +# 3.1.2 Soft neighborhood contrastive learning on unlabeled data + +When learning on unlabeled data, only the unsupervised contrastive loss Eq. 1 can be used. However, the samples within the same class could be mistakenly treated as negatives due to the missing labels. In addition, the number of negative pairs significantly surpasses positive pairs. Such imbalanced loss contribution could be sub-optimal. Aligning the positive and negative pairs with the true classes + +emerges as a desired solution. [47] has attempted to address the limitations by mining more positive pairs in the neighbored of each data sample. However, the pseudo-positive pairs are treated equally, regardless of how close they are to that data sample. To address this issue, we propose to encode soft positive correlation among instance neighbors to achieve adaptive contribution, as shown in Fig. 2 (a). + +Specifically, for each $\mathbf{x}_i$ , we first use the nearest neighbor operator on the projected features to select candidate neighbors. We denote them as $NN(\mathbf{z}_i)_k$ with $k$ as the index. We then pass them and $\mathbf{z}_i$ to an attention module to predict a set of positiveness values $\mathbf{w}_i = \{w_{ik}\} \in (0,1)$ to weight the contribution of $NN(\mathbf{z}_i)_k$ to the loss. Accordingly, the soft neighborhood contrastive loss is defined as: + +$$ +\mathcal {L} _ {i} ^ {\text {s o f t}} = - \frac {1}{| N N (\mathbf {z} _ {i}) |} \sum_ {k \in N N (\mathbf {z} _ {i})} \log \frac {w _ {i k} \cdot \exp \left(\mathbf {z} _ {i} \cdot \mathbf {z} _ {k} / \tau\right)}{\sum_ {n} \mathbb {I} _ {[ n \neq i ]} \exp \left(\mathbf {z} _ {i} \cdot \mathbf {z} _ {n} / \tau\right)} \tag {4} +$$ + +Candidate neighborhood. For each batch of data, we first compute their features $\mathcal{F}$ from the projection head at once. For each reference view $\mathbf{x}_i$ , we retrieve nearest neighbors by comparing the cosine similarity to a threshold $\epsilon$ as: + +$$ +N N (\mathbf {z} _ {i}) = \{\mathbf {F} \}, \text {f o r} \mathbf {F} \text {i n} \mathcal {F}, \text {i f} \cos (\mathbf {z} _ {i}, \mathbf {F}) \geq \epsilon \tag {5} +$$ + +where $\mathbf{z}_i$ and $\mathbf{F} \in \mathcal{F}$ are normalized before computation. + +Positiveness generation. Fig. 2 (a) shows an intuitive example of the candidate neighbors. The first two neighbors belong to the same category as the reference 'tiger' sample, while the $3^{rd}$ and $4^{th}$ neighbors are partially related (i.e., they belong to the 'lion' and 'leopard' categories, but not 'tiger'). The remaining instances are not related to 'tiger'. Therefore, the first four instances tend to be selected and they should contribute adaptively to the loss. We propose to learn an attention module to measure the soft correlations between the selected neighbors and the reference instance (instead of the binary form in [47]). Given two inputs $\mathbf{z}_i$ and $NN(\mathbf{z}_i)_k$ , we can calculate the positiveness score as: + +$$ +\mathbf {w} _ {i} = \operatorname {S o f t m a x} \left[ f _ {1} \left(\mathbf {z} _ {i}\right) \times f _ {2} \left(N N \left(\mathbf {z} _ {i}\right) _ {k}\right) ^ {T} \right] \tag {6} +$$ + +where $f_{1}(\cdot)$ and $f_{2}(\cdot)$ are the new projection layers and $\times$ denotes the cross attention operator. Eq. 6 is then normalized so that $\mathbf{w}_{i}$ has a max value as 1. Note that $f_{1}(\cdot)$ and $f_{2}(\cdot)$ can also be the non-parametric identity mappings, which are empirically found to be more effective. This observation may be attributed to the self-supervised learning paradigm, where the objective is to train the encoder effectively. Simplifying the attention module leads to less overfitting and improves learning attentive features. + +# 3.2. Learning to incrementally discover categories + +The main limitation of the prior works is that the labeled set $S^0$ is not fully exploited [7]. Instead of performing only representation learning on $S^0$ [21, 45], we borrow + +Algorithm 1 The optimization procedure of MetaGCD +Require: $\alpha, \beta, \gamma$ : learning rates +Require: $S^0$ : training set of labeled classes +1: randomly initialize parameters $\theta$ +2: while not converged do +3: $\mathcal{D} = \left\{\left(\mathcal{D}_{tr}^j,\mathcal{D}_{te}^j\right)\right\}_{j=0}^T$ +4: ▷ sample a pseudo incremental sequence +5: $\mathcal{P} = \emptyset$ ▷ empty cumulative pseudo test set +6: $\theta^{E,P}\gets \theta^{E,P} - \gamma \nabla_{\theta^{E,P}}\mathcal{L}_{labeled}(\mathbf{x}_{tr}^0,\mathbf{y}_{tr}^0;\theta)$ +7: ▷ update parameters using pseudo labeled classes +8: $\mathcal{P} = \mathcal{P}\cup \mathcal{D}_{te}^{0}$ ▷ accumulate test set of sess-0 +9: for $j = 1,\dots,T$ do +10: $\tilde{\theta}^{E,P} = \theta^{E,P} - \alpha \nabla_{\theta^{E,P}}\mathcal{L}_{soft}(\mathbf{x}_{tr}^j;\theta)$ +11: ▷ compute adapted params with unlabeled samples +12: $\mathcal{P} = \mathcal{P}\cup \mathcal{D}_{te}^j$ ▷ accumulate test set of sess-j +13: $\theta \gets \theta -\beta \nabla_{\theta}\sum_{(\mathcal{X},\mathcal{Y})\in \mathcal{P}}\mathcal{L}_{scl}(\mathcal{X},\mathcal{Y};\tilde{\theta}^E,\tilde{\theta}^P)$ +15: ▷ update meta-params $\theta$ to new session +16: end for +17: end while + +the meta-learning paradigm (in particular MAML [12]) to learn how to continually discover new classes. In few-shot learning, during meta-training, MAML constructs few-shot tasks to mimic the meta-testing scenario to achieve learning to quickly adapt. In our C-GCD case, the online continual class discovery tasks can be viewed as the "meta-testing" stage. Therefore, we propose to simulate the continual setting using $S^0$ during offline training, as shown in Fig. 2 (b). We aim to produce a model initialization that is trained by aligning the training and evaluation objectives so that it is endowed with the capability to effectively discover novel classes with less forgetting during evaluation. + +Sequential task sampling. To mimic the evaluation process, we sample sequential learning tasks from $\mathcal{S}^0$ [7]. Specifically, we first randomly separate the $S^0$ into pseudo labeled and pseudo unlabeled classes without overlapping. Next, we sample a sequence of $T + 1$ sessions, $\mathcal{D} = \{(\mathcal{D}_{tr}^j,\mathcal{D}_{te}^j)\}_{j = 0}^T$ , where $\mathcal{D}_{tr}^j$ and $\mathcal{D}_{te}^j$ are the training and test set for the $j^{th}$ session. For the training splits $\{\mathcal{D}_{tr}^j\}$ , we follow the evaluation protocol to only allow the first session to contain labeled data, (i.e., $\mathcal{D}_{tr}^0 = \{\mathbf{x}_{tr}^0,\mathbf{y}_{tr}^0\}$ ) and the rest with unlabeled data (i.e., $\mathcal{D}_{tr}^j = \{\mathbf{x}_{tr}^j\}$ , for $j > 0$ ). We also set the first session to contain a larger number of samples, i.e., $\left|\mathcal{D}_{tr}^0\right| \gg \left|\mathcal{D}_{tr}^{j > 0}\right|$ to simulate the C-GCD setting where the model is first trained during an offline training stage with a large amount of data. For the test splits $\{\mathcal{D}_{te}^j\}$ , all of them contain labels that will be used during the optimization (i.e., $\mathcal{D}_{te}^j = \{\mathbf{x}_{te}^j,\mathbf{y}_{te}^j\}, \forall j$ ). Note that $\mathcal{D}_{te}^j$ only contains the test data belonging to the current session $j$ . + +Meta-training. For each sampled sequence $\mathcal{D}$ , we let the model continually explore the incoming unlabeled data in + +an unsupervised manner. To reduce the forgetting issue due to learning new knowledge, we utilize the bi-level optimization [12, 8, 7] to directly formulate incrementally discovering without forgetting as the meta-objective. The meta-learning procedure is illustrated in Alg. 1 and Fig. 2 (b). Concretely, we decouple the network as $\theta = \{\theta^{E},\theta^{P}\}$ , where $\theta^{E}$ and $\theta^{P}$ are the encoder and projection layers. At each incremental session, we aim to evaluate all the classes that have encountered so far. Hence, at the beginning of each sequence, we define an empty cumulative pseudo test set $\mathcal{P}$ to store the test samples from previous sessions. After that, we first train $\theta$ on the pseudo labeled classes $(j = 0)$ using the unsupervised and supervised contrastive loss (Eq. 3). At each $j^{th}$ session $(j > 0)$ , we update $\theta$ on unlabeled samples $\mathcal{D}_{tr}^{j} = \{\mathbf{x}_{tr}^{j}\}$ via a few gradient steps: + +$$ +\tilde {\theta} ^ {E, P} = \theta^ {E, P} - \alpha \nabla_ {\theta^ {E, P}} \mathcal {L} _ {s o f t} (\mathbf {x} _ {t r} ^ {j}; \theta) \tag {7} +$$ + +where $\mathcal{L}_{soft}(\cdot)$ is the proposed soft neighborhood contrastive loss (Eq. 4). It aims to discriminate uncorrelated samples while absorbing correlated ones. By thoroughly exploring the unlabeled data, it maintains comprehensive old knowledge while efficiently discovering novel classes. + +Eq. 7 mimics how the model discovers novel classes on the incoming unlabeled data at test-time. Ideally, we like the adapted $\tilde{\theta}^{E,P}$ to perform well on all encountered classes. The test data from previous sessions and the current session separately reflect the catastrophic forgetting robustness and novel class discovery capability. Thus, we append $\mathcal{D}_{te}^{j}$ to $\mathcal{P}$ . Accordingly, the meta-objective is defined as follows for the outer loop of the meta-level optimization: + +$$ +\min _ {\theta^ {E}, \theta^ {P}} \sum_ {(\mathcal {X}, \mathcal {Y}) \in \mathcal {P}} \mathcal {L} _ {s c l} (\mathcal {X}, \mathcal {Y}; \tilde {\theta} ^ {E}, \tilde {\theta} ^ {P}) \tag {8} +$$ + +where $\mathcal{L}_{scl}(\cdot)$ is the supervised contrastive loss in Eq. 1. Note that the optimization is performed on $\theta$ , although $\mathcal{L}_{scl}(\cdot)$ is a function of $\tilde{\theta}^E$ and $\tilde{\theta}^P$ . The meta-objective in Eq. 8 is then optimized using gradient descent, as shown in Line 13 of Alg. 1. We empty $\mathcal{P}$ when all $T + 1$ sessions are iterated. After meta-training, we obtain an initialization of the model $\theta$ which has been specifically trained to discover and learn novel objects from a sequence of unlabeled data. + +Meta-testing. It is worth mentioning that the procedure in Alg. 1 aligns with the evaluation protocol. After discovering novel classes at each incremental session, the model is evaluated on all encountered classes. Our meta-objective optimizes the model towards what it is supposed to do at evaluation to maximize the performance. In addition, despite some uncertainties that may occur for unsupervised learning, the model is constrained by a fully supervised meta-objective. Thus, when training converges, the meta-model $\theta$ is ready to discover novel classes while maintaining the old knowledge by only running Line 10 of Alg. 1. + +
DatasetLabeled SetUnlabeled Set
#class#image#class#image
CIFAR107280001022000
CIFAR100803200010018000
Tiny-ImageNet1506000020040000
+ +Table 1: Datasets used in our experiments. We show the number of classes in the labeled and unlabeled sets, as well as the number of samples. + +# 4. Experiments + +# 4.1. Dataset and setup + +Dataset. We construct the C-GCD benchmark using three widely used datasets as in NCD [40, 35, 47], i.e., CIFAR10 [23], CIFAR100 [23] and Tiny-ImageNet [25]. Each dataset is split into two subsets, 1) large-scale labeled samples accounting for $80\%$ of the known classes data constitute a labeled set for offline training; and 2) the remaining data containing known and novel classes are used as an unlabeled set for continual object discovery. In Tab. 1, we summarize the dataset splits used in our training. + +Session-wise data split. All labeled samples $S^0$ are used for offline training in our setting. During the online incremental learning stage, the unlabeled samples are dynamically added (i.e., sessions $t \geq 1$ ). Specifically, CIFAR10 is divided into 3 incremental sessions. In the $t^{th}(t > 0)$ session, 3000 unlabeled images from 1 novel class and 2000 unlabeled images from $7 + (t - 1) \times 1$ known classes are added. CIFAR100 is divided into 4 sessions, in which 1500 unlabeled images from 5 novel classes and 2000 unlabeled images from $80 + (t - 1) \times 5$ known classes are added in the $t^{th}$ session. The Tiny-ImageNet consists of 5 incremental sessions, each containing 3000 unlabeled images from 10 novel classes and 3000 unlabeled images from $150 + (t - 1) \times 10$ known classes. + +Sequential task sampling. During offline training, we use $S^0$ to sample sequential tasks. We first split $S^0$ into non-overlapping pseudo labeled and novel classes (4/3 for CIFAR10, 60/20 for CIFAR100 and 100/50 for TinyImageNet). For each task, the pseudo labeled set is first used to warm up the model, followed by $T$ incremental sessions of unlabeled samples containing the pseudo labeled and novel classes. Both the session number and the number of novel classes in each offline incremental session are consistent with the online incremental learning scenario. + +Evaluation metrics. After learning the model on unlabeled samples at every online incremental stage, we follow [40] to measure the clustering accuracy between the ground truth labels $y_{i}$ and the model's predictions $\hat{y}_{i}$ as: + +$$ +A C C = \max _ {p \in \mathcal {P} (\mathcal {Y})} \frac {1}{N} \sum \left(\mathbb {1} \left\{y _ {i} = p \left(\hat {y} _ {i}\right) \right\}\right), \tag {9} +$$ + +
MethodsCIFAR10 (Session Number)Final +Impro.
123
AllOldNewAllOldNewAllOldNewAllOldNewAllOldNew
RankStats69.3170.2058.6365.2367.8651.2038.1650.0135.94+54.50+47.22+48.77
FRoST73.9281.1766.4569.5679.7358.0467.7370.8451.13+24.93+26.39+33.58
VanillaGCD89.2497.9781.8085.1396.6774.6086.4195.0376.75+6.25+2.20+7.96
GM90.0098.4177.4087.3999.0173.4687.8697.1578.93+4.80+0.08+5.78
MetaGCD(ours)95.3899.0789.1593.3498.8185.3992.6697.2384.71
MethodsCIFAR100 (Session Number)Final +Impro.
1234
AllOldNewAllOldNewAllOldNewAllOldNewAllOldNew
RankStats62.3364.2231.6055.0158.5526.8551.7756.7025.4747.5154.5917.20+27.05+23.01+43.93
FRoST67.1468.5750.7367.0168.8252.6062.3565.4845.6755.8459.0642.95+18.72+18.54+18.18
VanillaGCD76.7877.9158.6073.6775.2960.7072.7774.7262.3371.4474.7558.20+3.12+2.85+2.93
GM78.2979.9166.0077.5879.6461.1374.5677.6058.1472.0275.9856.32+2.54+1.62+4.81
MetaGCD(ours)78.9679.3672.6078.6779.4166.8176.0678.2064.8774.5677.6061.13
MethodsTiny-ImageNet (Session Number)Final +Impro.
1234
AllOldNewAllOldNewAllOldNewAllOldNewAllOldNew
RankStats62.3964.5435.0155.8952.2334.2049.8846.1728.3344.2042.8724.5036.0935.2015.76
FRoST64.9267.8446.2859.5061.8640.6057.8660.6339.1455.6859.7136.5550.4953.7633.37
VanillaGCD75.9278.1762.1574.5377.7356.1273.6474.8557.3170.6971.1354.3566.1567.1754.43
GM76.3279.5563.6075.4378.1057.4072.6376.2954.8070.5476.8051.5067.3172.0850.90
MetaGCD(ours)78.6779.4166.8077.8979.9561.4075.2377.8661.2072.0075.6157.5570.2471.5358.46
+ +Table 2: Performance (in %) comparisons with the state-of-the-art methods on CIFAR10, CIFAR100, Tiny-ImageNet datasets. The results of other methods are obtained by running their released codes under the C-GCD setting. + +where $N$ is the total number of test samples and $\mathcal{P}(\mathcal{V})$ is the set of all permutations of the class labels $\mathcal{V}$ encountered so far. The optimal permutation can be obtained via the Hungarian algorithm [24]. Our main metric is ACC on 'All' classes, indicating the accuracy across all accumulated test sets so far. To decouple the evaluation on forgetting and discovery, we further report accuracy for both the 'Old' classes subset (samples in the test set belonging to previous known classes) and 'New' classes subset (samples in the test set belonging to novel classes). + +Implementation details. Following [40], we employ a vision transformer (ViT-B-16) [10] pretrained on ImageNet [9] with DINO [3] as the feature extractor throughout the paper. We use the Adam optimizer and the learning rates in Alg. 1 are set as $\gamma = 0.1$ , $\alpha = 0.001$ and $\beta = 0.0001$ . We use a batch size of 256 and $\lambda = 0.35$ to balance the losses in Eq. 3. Unless otherwise stated, we select the threshold $\epsilon$ to be 0.85 in Eq. 5. At the meta-training stage, we first perform training on pseudo labeled set for 50 epochs, followed by 10 inner and 1 outer gradient updates for incremental sessions. At the meta-test stage, we directly perform 20 gradient updates to adapt using unlabeled samples. Furthermore, we follow standard practice in self-supervised learning to use the same projection head as in [3] and discard it at test-time. + +# 4.2. Comparison with the state-of-the-art + +Since this paper considers a new problem setting, there is no prior work that we can directly compare. Nevertheless, we choose SOTA methods on NCD and run their codes under our C-GCD setting, including RankStats [16], VanillaGCD [40], and recent continual NCD models FRoST [35], GM [45]. Both RankStats and FRoST train two classifiers on top of a shared feature representation. The first head is fed images from the labeled set and is trained with the cross-entropy loss, while the second head sees only images from unlabeled images of novel classes. In order to adapt RankStats and FRoST to C-GCD, we train them with a single classification head for the total number of classes in the dataset. The sequential version of VanillaGCD is adopted and serves as the baseline for our model. We leverage the original training mechanism for GM. + +In Tab. 2, we report the All/Old/New class accuracy per incremental session for all methods, and the relative improvement for the final session. As we can see, the proposed method consistently outperforms all other methods on all three datasets among the most incremental sessions. Specifically, our MetaGCD surpasses the most recent method GM by $5.78\%$ , $4.81\%$ and $7.56\%$ on CIFAR10, CIFAR100 and Tiny-ImageNet datasets for the final New classes accuracy. + +
MethodsCIFAR100 (Session Number)Average Acc
1234
AllOldNewAllOldNewAllOldNewAllOldNewmAmOmN
Baseline76.7877.9158.6073.6775.2960.7072.7774.6262.3371.4474.7558.2073.6775.6459.96
+LCN77.2978.5365.4475.2077.6763.0874.5575.9163.6372.6275.4359.4074.9276.8962.89
+LSP77.9278.4568.7876.5378.2264.7174.8677.2464.0973.3476.8760.6075.6677.7064.55
+Meta-learning78.9679.3672.6078.6779.4166.8176.0678.2064.8774.5677.6061.1377.0678.6466.35
+ +Table 3: Ablation study of various components of our MetaGCD on the CIFAR100 dataset. We report 'All', 'Old' and 'New' class accuracy for each incremental session, and the average of all sessions such as mean 'All' (mA), mean 'Old' (mO) and mean 'New' accuracy (mN). Here CN denotes candidate neighbors and SP denotes soft positiveness. + +![](images/087bc3da845b31f71935cb67300089dcd2710b6c820598ba73aedbda46680128.jpg) +Figure 3: Class-wise performance on the CIFAR100 dataset. The confusion matrices show that our model significantly improves the baseline for both known and novel classes (separated by the red line). Especially for novel classes, the confusion matrix of our method has more concentrated values along the diagonal. + +![](images/635d80b87485e79afe54aa9a4c11cc66317cc68604c8c9e9969f87f7a21af487.jpg) +Figure 4: Hyper-parameter analysis on the CIFAR100 dataset regarding feature similarity threshold (left) and various numbers of novel classes (right). An appropriate threshold or the number of new classes helps to stabilize the training process and improve performance. + +Besides, our model outperforms the baseline VanillaGCD by $6.25\%$ , $3.12\%$ and $4.09\%$ for the final All classes. We also report the class-wise performance via the confusion matrices shown in Fig. 3. It is obvious that the baseline performs poorly, especially on the novel classes. However, the proposed model has a significant gain in discovering novel classes. Moreover, less forgetting is observed in our method, as more values are concentrated on the diagonal. + +# 4.3. Ablation Study + +We conduct ablation studies on the CIFAR100 dataset to evaluate each component in our proposed framework. + +Importance of neighborhood. In our contrastive learning framework, we compute the soft correlation to allow more positive pairs to contribute to the loss. As reported in the second row of Tab. 3, considering the neighborhood achieves a performance gain of $1.25\%$ (i.e., $74.92\%$ v.s. $73.67\%$ on the mean accuracy of All classes). The performance gain may come from the abundant comparisons from positive samples, which facilitates the current instance to align with more highly-correlated samples. We also conduct + +![](images/92c7e533a3ce878c8b9505e8443b862ea114e97d3b7ae0fc0befb26766ed9c82.jpg) + +experiments to assess the sensitivity of threshold $\epsilon$ when selecting the positive neighbor instances. Increasing $\epsilon$ allows more strict positive pairs, but some partially related samples might be ignored. On the other hand, reducing $\epsilon$ increases the likelihood of introducing true negative samples, which may negatively impact model performance. As empirically found in the left side of Fig. 4, a trade-off should be made, and a threshold of 0.85 achieves the best performance. + +Importance of soft positiveness. We then analyze the importance of soft positiveness to the recognition performance in the third row of Tab. 3. When we compute a correlation weight for each selected neighbor, the clustering accuracy on Novel classes increases from $62.89\%$ to $64.55\%$ . It indicates that the binary labeling strategy is insufficient to measure the correlation at the feature space, thus causing the backbone network to produce less discriminative representations compared with soft labeling methods. In the lower part of Fig. 2 (a), we show the correlation weight of selected neighbors with an input instance. The high score corresponds to the same category while the low score corresponds to less-correlated categories, which shows that our attention module is effective in modeling correlations between the input instance and each candidate neighbor. + +Effectiveness of meta-learning. Our meta-learning optimization strategy further improves All classes accuracy to $74.56\%$ for the final incremental session in the last row + +of Tab. 3. It demonstrates the effectiveness of the proposed method where the meta-objective specifically forces the model to discover novel classes without forgetting old classes. Additionally, we analyze the impact of the number of novel classes that are sampled during meta-training. To investigate this, we train separate models by setting the number of novel classes in the range of $\{1, 10\}$ . As illustrated on the right side of Fig. 4, a larger number of classes for sequence tasks is more optimal. When there are fewer classes, the model is at a higher risk of overfitting to certain classes rather than learning how to incrementally learn. + +# 5. Conclusion + +In this paper, we propose a more realistic setting for real-world applications, namely C-GCD. The ultimate goal of C-GCD is to discover novel classes while keeping the old knowledge without forgetting. We propose a meta-learning based optimization strategy to directly optimize the network to learn how to incrementally discover with less forgetting. In addition, we introduce a soft neighborhood contrastive learning to utilize the soft positiveness to adaptively support the current instances from their neighbors. Extensive experiments on three datasets demonstrate the superiority of our method over state-of-the-art methods. + +# 6. Acknowledgments + +This work was supported by the Fundamental Research Funds for the Central Universities (No. 2022JBZY019), the National Key Research and Development Project (No. 2018AAA0100300) and an NSERC Discovery grant. + +# References + +[1] Philip Bachman, R Devon Hjelm, and William Buchwalter. Learning representations by maximizing mutual information across views. Advances in Neural Information Processing Systems, 32, 2019. +[2] Peyman Bateni, Raghav Goyal, Vaden Masrani, Frank Wood, and Leonid Sigal. Improved few-shot visual classification. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 14493-14502, 2020. +[3] Mathilde Caron, Hugo Touvron, Ishan Misra, Hervé Jégou, Julien Mairal, Piotr Bojanowski, and Armand Joulin. Emerging properties in self-supervised vision transformers. In Proceedings of the IEEE International Conference on Computer Vision, pages 9650-9660, 2021. +[4] Can Chen, Yingxueff Zhang, Jie Fu, Xue Steve Liu, and Mark Coates. Bidirectional learning for offline infinite-width model-based optimization. NeurIPS, 2022. +[5] Can Chen, Shuhao Zheng, Xi Chen, Erqun Dong, Xue Steve Liu, Hao Liu, and Dejing Dou. Generalized dataweighting via class-level gradient manipulation. NeurIPS, 2021. +[6] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning + +of visual representations. In Proceedings of the IEEE International Conference on Machine Learning, pages 1597-1607, 2020. +[7] Zhixiang Chi, Li Gu, Huan Liu, Yang Wang, Yuanhao Yu, and Jin Tang. Meta-scl: A meta-learning approach for few-shot class incremental learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 14166-14175, 2022. +[8] Zhixiang Chi, Yang Wang, Yuanhao Yu, and Jin Tang. Test-time fast adaptation for dynamic scene deblurring via meta-auxiliary learning. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9137-9146, 2021. +[9] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 248-255, 2009. +[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In Proceedings of the IEEE International Conference on Learning Representations, 2021. +[11] Enrico Fini, Enver Sangineto, Stéphane Lathuilière, Zhun Zhong, Moin Nabi, and Elisa Ricci. A unified objective for novel class discovery. In Proceedings of the IEEE International Conference on Computer Vision, pages 9284-9292, 2021. +[12] Chelsea Finn, Pieter Abbeel, and Sergey Levine. Model-agnostic meta-learning for fast adaptation of deep networks. In Proceedings of International Conference on Machine Learning, pages 1126–1135, 2017. +[13] Li Gu, Zhixiang Chi, Huan Liu, Yuanhao Yu, and Yang Wang. Improving protonet for few-shot video object recognition: Winner of orbit challenge 2022. arXiv preprint arXiv:2210.00174, 2022. +[14] Michael Gutmann and Aapo Hyvarinen. Noise-contrastive estimation: A new estimation principle for unnormalized statistical models. In Proceedings of the International Conference on Artificial Intelligence and Statistics, pages 297–304, 2010. +[15] Kai Han, Sylvestre-Alvise Rebuffi, Sebastien Ehrhardt, Andrea Vedaldi, and Andrew Zisserman. Automatically discovering and learning new visual categories with ranking statistics. In International Conference on Learning Representations, 2020. +[16] Kai Han, Sylvestre-Alvise Rebuffi, Sebastien Ehrhardt, Andrea Vedaldi, and Andrew Zisserman. Autonovel: Automatically discovering and learning novel visual categories. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(10):6767-6781, 2021. +[17] Kai Han, Andrea Vedaldi, and Andrew Zisserman. Learning to discover novel visual categories via deep transfer clustering. In Proceedings of the IEEE International Conference on Computer Vision, pages 8401-8409, 2019. +[18] Kaiming He, Haoqi Fan, Yuxin Wu, Saining Xie, and Ross Girshick. Momentum contrast for unsupervised visual rep + +resentation learning. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 9729-9738, 2020. +[19] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016. +[20] Khurram Javed and Martha White. Meta-learning representations for continual learning. Advances in Neural Information Processing Systems, 32, 2019. +[21] KJ Joseph, Sujoy Paul, Gaurav Aggarwal, Soma Biswas, Piyush Rai, Kai Han, and Vineeth N Balasubramanian. Novel class discovery without forgetting. In Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 570-586, 2022. +[22] Prannay Khosla, Piotr Teterwak, Chen Wang, Aaron Sarna, Yonglong Tian, Phillip Isola, Aaron Maschinot, Ce Liu, and Dilip Krishnan. Supervised contrastive learning. Advances in Neural Information Processing Systems, 33:18661-18673, 2020. +[23] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images. Handbook of Systemic Autoimmune Diseases, 1(4), 2009. +[24] Harold W Kuhn. The hungarian method for the assignment problem. Naval Research Logistics Quarterly, 2(1-2):83-97, 1955. +[25] Ya Le and Xuan Yang. Tiny imagenet visual recognition challenge. CS 231N, 7(7):3, 2015. +[26] Zhizhong Li and Derek Hoiem. Learning without forgetting. IEEE Transactions on Pattern Analysis and Machine Intelligence, 40(12):2935-2947, 2017. +[27] Hanwen Liang, Niamul Quader, Zhixiang Chi, Lizhe Chen, Peng Dai, Juwei Lu, and Yang Wang. Self-supervised spatiotemporal representation learning by exploiting video continuity. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 1564-1573, 2022. +[28] Huan Liu, Zhixiang Chi, Yuanhao Yu, Yang Wang, Jun Chen, and Jin Tang. Meta-auxiliary learning for future depth prediction in videos. In Proceedings of the IEEE Winter Conference on Applications of Computer Vision, pages 5756-5765, 2023. +[29] Huan Liu, Li Gu, Zhixiang Chi, Yang Wang, Yuanhao Yu, Jun Chen, and Jin Tang. Few-shot class-incremental learning via entropy-regularized data-free replay. In Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 146–162, 2022. +[30] Huan Liu, Zijun Wu, Liangyan Li, Sadaf Salehkalaibar, Jun Chen, and Keyan Wang. Towards multi-domain single image dehazing via test-time training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5831-5840, 2022. +[31] Yaoyao Liu, Yuting Su, An-An Liu, Bernt Schiele, and Qianru Sun. Mnemonics training: Multi-class incremental learning without forgetting. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 12245–12254, 2020. +[32] Yiwei Lu, Frank Yu, Mahesh Kumar Krishna Reddy, and Yang Wang. Few-shot scene-adaptive anomaly detection. In + +Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 125-141, 2020. +[33] Tian Pan, Yibing Song, Tianyu Yang, Wenhao Jiang, and Wei Liu. Videomoco: Contrastive video representation learning with temporally adversarial examples. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 11205-11214, 2021. +[34] Sachin Ravi and Hugo Larochelle. Optimization as a model for few-shot learning. In International Conference on Learning Representations, 2017. +[35] Subhankar Roy, Mingxuan Liu, Zhun Zhong, Nicu Sebe, and Elisa Ricci. Class-incremental novel class discovery. In Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 317-333, 2022. +[36] Adam Santoro, Sergey Bartunov, Matthew Botvinick, Daan Wierstra, and Timothy Lillicrap. Meta-learning with memory-augmented neural networks. In International Conference on Machine Learning, pages 1842-1850, 2016. +[37] Karen Simonyan and Andrew Zisserman. Very deep convolutional networks for large-scale image recognition. In International Conference on Learning Representations, 2014. +[38] Jake Snell, Kevin Swersky, and Richard Zemel. Prototypical networks for few-shot learning. Advances in Neural Information Processing Systems, 30, 2017. +[39] Jae Woong Soh, Sunwoo Cho, and Nam Ik Cho. Meta-transfer learning for zero-shot super-resolution. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 3516-3525, 2020. +[40] Sagar Vaze, Kai Han, Andrea Vedaldi, and Andrew Zisserman. Generalized category discovery. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 7492-7501, 2022. +[41] Yue Wu, Yinpeng Chen, Lijuan Wang, Yuancheng Ye, Zicheng Liu, Yandong Guo, and Yun Fu. Large scale incremental learning. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 374-382, 2019. +[42] Yanan Wu, Tengfei Liang, Songhe Feng, Yi Jin, Gengyu Lyu, Haojun Fei, and Yang Wang. Metazscil: A meta-learning approach for generalized zero-shot class incremental learning. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 37, pages 10408-10416, 2023. +[43] Chi Zhang, Nan Song, Guosheng Lin, Yun Zheng, Pan Pan, and Yinghui Xu. Few-shot incremental learning with continually evolved classifiers. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 12455–12464, 2021. +[44] Marvin Zhang, Henrik Marklund, Nikita Dhawan, Abhishek Gupta, Sergey Levine, and Chelsea Finn. Adaptive risk minimization: Learning to adapt to domain shift. Advances in Neural Information Processing Systems, 34:23664-23678, 2021. +[45] Xinwei Zhang, Jianwen Jiang, Yutong Feng, Zhi-Fan Wu, Xibin Zhao, Hai Wan, Mingqian Tang, Rong Jin, and Yue Gao. Grow and merge: A unified framework for continuous categories discovery. Advances in Neural Information Processing Systems, 2022. + +[46] Tao Zhong, Zhixiang Chi, Li Gu, Yang Wang, Yuanhao Yu, and Jin Tang. Meta-dmoe: Adapting to domain shift by metadata distillation from mixture-of-experts. Advances in Neural Information Processing Systems, 35:22243-22257, 2022. +[47] Zhun Zhong, Enrico Fini, Subhankar Roy, Zhiming Luo, Elisa Ricci, and Nicu Sebe. Neighborhood contrastive learning for novel class discovery. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 10867-10875, 2021. \ No newline at end of file diff --git a/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/images.zip b/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..63707f1c4f17ddea6ff6124460964f692782321b --- /dev/null +++ b/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:59e8d4b480972de65bc2c48273343594bfe9249cca1e251940df08329c734873 +size 625543 diff --git a/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/layout.json b/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..4df45fa0dc67430d79e3fdf444f4edf52fee916c --- /dev/null +++ b/2023/MetaGCD_ Learning to Continually Learn in Generalized Category Discovery/layout.json @@ -0,0 +1,9120 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 56, + 103, + 538, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 103, + 538, + 121 + ], + "spans": [ + { + "bbox": [ + 56, + 103, + 538, + 121 + ], + "type": "text", + "content": "MetaGCD: Learning to Continually Learn in Generalized Category Discovery" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 162, + 142, + 453, + 157 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 162, + 142, + 453, + 157 + ], + "spans": [ + { + "bbox": [ + 162, + 142, + 453, + 157 + ], + "type": "text", + "content": "Yanan Wu" + }, + { + "bbox": [ + 162, + 142, + 453, + 157 + ], + "type": "inline_equation", + "content": "^{1,2*}" + }, + { + "bbox": [ + 162, + 142, + 453, + 157 + ], + "type": "text", + "content": ", Zhixiang Chi" + }, + { + "bbox": [ + 162, + 142, + 453, + 157 + ], + "type": "inline_equation", + "content": "^{3*}" + }, + { + "bbox": [ + 162, + 142, + 453, + 157 + ], + "type": "text", + "content": ", Yang Wang" + }, + { + "bbox": [ + 162, + 142, + 453, + 157 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 162, + 142, + 453, + 157 + ], + "type": "text", + "content": ", Songhe Feng" + }, + { + "bbox": [ + 162, + 142, + 453, + 157 + ], + "type": "inline_equation", + "content": "^{1,2\\dagger}" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 130, + 157, + 488, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 130, + 157, + 488, + 185 + ], + "spans": [ + { + "bbox": [ + 130, + 157, + 488, + 185 + ], + "type": "text", + "content": "1Key Laboratory of Big Data & Artificial Intelligence in Transportation, Ministry of Education, Beijing Jiaotong University, Beijing, 100044, China" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 56, + 185, + 558, + 241 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 185, + 558, + 241 + ], + "spans": [ + { + "bbox": [ + 56, + 185, + 558, + 241 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 56, + 185, + 558, + 241 + ], + "type": "text", + "content": "School of Computer and Information Technology, Beijing Jiaotong University, Beijing, 100044, China \n" + }, + { + "bbox": [ + 56, + 185, + 558, + 241 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 56, + 185, + 558, + 241 + ], + "type": "text", + "content": "Department of Electrical and Computer Engineering, University of Toronto, Toronto, M5G1V7, Canada \n" + }, + { + "bbox": [ + 56, + 185, + 558, + 241 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 56, + 185, + 558, + 241 + ], + "type": "text", + "content": "Department of Computer Science and Software Engineering, Concordia University, Montreal, H3G2J1, Canada" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 83, + 243, + 527, + 255 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 83, + 243, + 527, + 255 + ], + "spans": [ + { + "bbox": [ + 83, + 243, + 527, + 255 + ], + "type": "text", + "content": "{ynwu0510,shfeng}@bjtu.edu.cn,zhixiang.chi@mail.utoronto.ca,yang.wang@concordia.ca" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 143, + 282, + 191, + 295 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 282, + 191, + 295 + ], + "spans": [ + { + "bbox": [ + 143, + 282, + 191, + 295 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 308, + 290, + 582 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 308, + 290, + 582 + ], + "spans": [ + { + "bbox": [ + 46, + 308, + 290, + 582 + ], + "type": "text", + "content": "In this paper, we consider a real-world scenario where a model that is trained on pre-defined classes continually encounters unlabeled data that contains both known and novel classes. The goal is to continually discover novel classes while maintaining the performance in known classes. We name the setting Continual Generalized Category Discovery (C-GCD). Existing methods for novel class discovery cannot directly handle the C-GCD setting due to some unrealistic assumptions, such as the unlabeled data only containing novel classes. Furthermore, they fail to discover novel classes in a continual fashion. In this work, we lift all these assumptions and propose an approach, called MetaGCD, to learn how to incrementally discover with less forgetting. Our proposed method uses a meta-learning framework and leverages the offline labeled data to simulate the testing incremental learning process. A meta-objective is defined to revolve around two conflicting learning objectives to achieve novel class discovery without forgetting. Furthermore, a soft neighborhood-based contrastive network is proposed to discriminate uncorrelated images while attracting correlated images. We build strong baselines and conduct extensive experiments on three widely used benchmarks to demonstrate the superiority of our method." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 605, + 127, + 618 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 605, + 127, + 618 + ], + "spans": [ + { + "bbox": [ + 47, + 605, + 127, + 618 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 625, + 287, + 686 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 625, + 287, + 686 + ], + "spans": [ + { + "bbox": [ + 46, + 625, + 287, + 686 + ], + "type": "text", + "content": "Object categories in real-world environments are dynamically evolving and expanding over time. However, conventional deep learning-based visual recognition methods normally focus on closed-world scenarios with pre-defined categories [19, 37]. Such systems are brittle when deployed to" + } + ] + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 310, + 281, + 544, + 452 + ], + "blocks": [ + { + "bbox": [ + 310, + 281, + 544, + 452 + ], + "lines": [ + { + "bbox": [ + 310, + 281, + 544, + 452 + ], + "spans": [ + { + "bbox": [ + 310, + 281, + 544, + 452 + ], + "type": "image", + "image_path": "077eab0066f1e2e63bd1cb6c52b242d4b07a55a192300dd264147b6651586117.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 459, + 547, + 555 + ], + "lines": [ + { + "bbox": [ + 304, + 459, + 547, + 555 + ], + "spans": [ + { + "bbox": [ + 304, + 459, + 547, + 555 + ], + "type": "text", + "content": "Figure 1: Illustration of our C-GCD setting. During the offline training, we learn an initial model based on training samples of the labeled set. During each subsequent online incremental learning, we are given some unlabeled images belonging to both known and novel classes. Our goal is to update the model in each incremental session so that the model can maintain the performance on old classes while discovering novel classes." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 580, + 546, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 580, + 546, + 628 + ], + "spans": [ + { + "bbox": [ + 304, + 580, + 546, + 628 + ], + "type": "text", + "content": "an ever-changing realistic open-world setting, where object instances may come from new categories. In contrast, recognizing the known categories and utilizing them to discern the unknowns are intrinsic to human perception." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 630, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 630, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 630, + 547, + 714 + ], + "type": "text", + "content": "Recently, discovering the novel classes among unlabeled data has been an active area of research [15, 11, 40, 35, 45]. However, most prior works make several assumptions that are unrealistic in practice. For example, the works in [15, 11, 40] assume the co-existence of both labeled data (with known classes) and unlabeled data (contains potential unknown classes to be discovered) at the training phase and" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 693, + 208, + 703 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 693, + 208, + 703 + ], + "spans": [ + { + "bbox": [ + 58, + 693, + 208, + 703 + ], + "type": "text", + "content": "*The authors contributed equally to this work." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 59, + 703, + 137, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 703, + 137, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 703, + 137, + 712 + ], + "type": "text", + "content": "† Corresponding Author" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1655" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 193 + ], + "type": "text", + "content": "the models are learned from scratch. This leads to repetitive large-scale training every time when new classes are expected to be discovered. The works in [15, 11, 35, 45] assume the newly encountered unlabeled data only belongs to the novel classes. This is unrealistic in practice. To meet such conditions, a rigorous filtering method is needed to precisely filter out known class data to avoid degenerate solutions. Due to these limitations, none of these works can be used to build recognition systems that can deal with evolving object categories sequentially over a long time horizon." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 195, + 289, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 195, + 289, + 495 + ], + "spans": [ + { + "bbox": [ + 46, + 195, + 289, + 495 + ], + "type": "text", + "content": "In this paper, we consider a more flexible setting for real-world applications. Let us consider the application of home robots. The robots are equipped with an offline trained object recognition model on pre-defined categories during manufacturing. After deployment, the robots are expected to operate in diverse environments. While operating, they continually receive data that belongs to known and possibly unknown classes. Ideally, we would like the robots to continually discover and learn novel classes from such data. We dub such a setting as Continuous Generalized Class Discovery (C-GCD). As shown in Fig. 1, C-GCD has two phases: 1) an offline training phase that allows the model to be trained on large-scale labeled data with pre-defined classes; 2) when the model is deployed, it continually encounters unlabeled data that comes from both known and novel classes on a longer horizon. At each incremental session, the data from the previous sessions is inaccessible. The model needs to precisely classify the known classes and discover novel ones to expand its knowledge base. Obviously, the main challenge of C-GCD is to discover the novel classes among unlabeled images that contain both known and unknown categories while maintaining the performance on old classes. However, learning novel knowledge normally leads to notorious catastrophic forgetting [7], which further exacerbates the model performance." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 498, + 289, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 498, + 289, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 498, + 289, + 713 + ], + "type": "text", + "content": "There are some initial attempts on C-GCD [21, 45]. However, they only consider C-GCD at the deployment stage mentioned above. The offline training stage is not fully exploited in these works. Concretely, the labeled data during offline training is only used for pre-training model representations. Therefore, the model at the offline stage is unaware of its subsequent learning duty (discover novel classes and retain the performance of known classes) [8] and is also prone to overfit to the labeled set [40]. Such learning objective misalignment leads to cumbersome heuristic strategies to facilitate the new learning task while keeping the previous knowledge. For example, to learn the novel classes, [21] requires a self-labeling method, which may cause error propagation. A routing strategy is also required to determine the known and novel classifier heads. [45] relies on a thresholding method to filter novel instances. However, the overall robustness of the method can be sensitive to the threshold. To alleviate the" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": "forgetting issues, [21, 45] propose to distill the knowledge from the pre-trained base models. Data replay is also utilized to either directly select representative labeled exemplars [45] or generate pseudo-latent representations from them [21]. Consequently, the base models and the replay buffers have to be stored locally which may cause storage problems, especially in a resource-constraint environment." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 304, + 157, + 546, + 407 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 157, + 546, + 407 + ], + "spans": [ + { + "bbox": [ + 304, + 157, + 546, + 407 + ], + "type": "text", + "content": "In this work, we propose a fully learning-based solution, named MetaGCD, to minimize the hand-engineered heuristics in prior works. Concretely, at the offline training phase, instead of pre-training a model representation, we directly train an initialization that is learned to discover novel categories with less forgetting when deployed. It is realized by meta-learning-based bi-level optimization [12] to couple the offline training and downstream learning objectives. During the offline training, we simulate the testing scenario and construct pseudo incremental novel class discovery sessions using the labeled data. At each incremental session, we discover novel classes by updating the model using an unsupervised contrastive loss. The meta-objective is then defined by validating the updated model on all classes encountered on a labeled pseudo test set. Therefore, the meta-objective of the offline training is aligned with the evaluation protocol at deployment. It enforces the model to learn to balance two conflicting objectives, namely discovering new objects and not-forgetting old objects. The meta-objective also reinforces the unsupervised updated model to be supervised by the true labels to ensure valid novel class discovery." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 407, + 547, + 538 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 407, + 547, + 538 + ], + "spans": [ + { + "bbox": [ + 304, + 407, + 547, + 538 + ], + "type": "text", + "content": "MetaGCD uses unsupervised contrastive learning to explore the relationship among instances for novel class discovery. Therefore, it is less prone to label overfitting [40]. However, we observe that the negative pairs in contrastive learning normally dominate the loss function. So we further propose soft neighborhood contrastive learning to mine more positiveness. Concretely, for each image instance, we select the nearest candidate neighbors within the batch to treat them as soft positive samples to contribute to the discriminative feature learning. Overall, our contributions are summarised as follows:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 317, + 545, + 545, + 714 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 317, + 545, + 545, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 545, + 545, + 605 + ], + "spans": [ + { + "bbox": [ + 317, + 545, + 545, + 605 + ], + "type": "text", + "content": "- We consider a realistic setting C-GCD for applications in real-world scenarios. It allows the model trained on pre-defined classes to continually explore novel classes through incoming unlabeled data while simultaneously keeping the performance of known classes." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 606, + 545, + 654 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 606, + 545, + 654 + ], + "spans": [ + { + "bbox": [ + 317, + 606, + 545, + 654 + ], + "type": "text", + "content": "- We propose a meta-learning approach where the learning objective is well aligned with the evaluation protocol during testing. It directly optimizes the model to achieve novel object discovery without forgetting." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 654, + 545, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 654, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 317, + 654, + 545, + 689 + ], + "type": "text", + "content": "- A soft neighborhood contrastive learning method is also proposed to mine more soft positive pairs to elevate the discovery capability." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 317, + 689, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 689, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 317, + 689, + 545, + 714 + ], + "type": "text", + "content": "- We establish strong baselines and show that our method achieves superior performance with less hand" + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1656" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 67, + 72, + 269, + 85 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 269, + 85 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 269, + 85 + ], + "type": "text", + "content": "engineered design through extensive experiments." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 95, + 134, + 107 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 95, + 134, + 107 + ], + "spans": [ + { + "bbox": [ + 47, + 95, + 134, + 107 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 115, + 289, + 474 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 115, + 289, + 474 + ], + "spans": [ + { + "bbox": [ + 47, + 115, + 289, + 474 + ], + "type": "text", + "content": "Discovering novel classes. Novel Class Discovery (NCD) aims to discover the novel classes from unlabeled data by utilizing the prior knowledge from the labeled data [15, 11, 17]. However, NCD assumes that the unlabeled data only belongs to the novel classes, which is unrealistic. Alternatively, a generalized version of NCD (GCD) [40] relaxes such constrain. Although GCD allows the unlabeled data to contain both known and novel classes, they are both required to be present in the training phase. It leads to repetitive large-scale training when different groups of unlabeled data are continually presented to the recognition system. Recently, a class incremental variant of NCD (class-iNCD) is proposed to learn the tasks of labeled known and unlabeled novel classes sequentially [35]. When learning the novel classes, the data of old classes are inaccessible. In the end, the model is evaluated on all encountered classes. Nevertheless, only a few incremental sessions containing unlabeled novel classes are allowed in class-iNCD. This limitation hinders its applicability under the realistic setting with continually evolved object categories. Our proposed C-GCD alleviates the above limitations in real-world scenarios. Our approach can learn from labeled pre-defined classes during offline training, and then continuously encounter unlabeled data with both known and novel classes after deployment. Our model will learn to discover novel classes without forgetting old classes. C-GCD is also related to the classic class-incremental setting [26, 41, 31, 29]. But C-GCD is more challenging as the newly evolved classes are unlabeled and an automatic class discovery mechanism is required [21]." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 474, + 289, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 474, + 289, + 653 + ], + "spans": [ + { + "bbox": [ + 47, + 474, + 289, + 653 + ], + "type": "text", + "content": "Meta-learning. Existing meta-learning methods can be categorized into: 1) model-based [36, 2, 4]; 2) Optimization-based [34, 12, 5]; and 3) metric-based [38]. Typical meta-learning methods utilize bi-level optimization to train a model that is applicable for downstream adaptations. Our work is built upon MAML [12], which trains a model initialization through episodes of tasks for fast adaptation via gradient updates. Such learning paradigm has been widely applied in different vision tasks, such as test-time adaptation [39, 28, 32, 30], continual learning [43, 20, 42] and domain shift [44, 46, 13]. In our case, the adaptation is achieved in an unsupervised manner, and the bi-level optimization is utilized to combine two conflicting learning objectives: discovering the novel classes without forgetting the old classes." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 653, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 653, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 653, + 289, + 715 + ], + "type": "text", + "content": "Contrastive learning. Contrastive learning has been popular in self-supervised visual representation learning [1, 6, 18, 33, 27]. It explores the relationships among data instances by constructing positive and negative pairs. Therefore, the overfitting on the label space is reduced to im" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 72, + 547, + 157 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 157 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 157 + ], + "type": "text", + "content": "prove the generalization of downstream tasks. Zhong et al. [47] apply contrastive learning to discover novel classes by exploring the data neighborhood and choosing pseudopositive pairs. However, those pseudo-positive pairs contribute equally regardless of their closeness compared to the reference sample. In this work, we introduce the soft positiveness concept to allow adaptive contribution." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 305, + 166, + 435, + 179 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 166, + 435, + 179 + ], + "spans": [ + { + "bbox": [ + 305, + 166, + 435, + 179 + ], + "type": "text", + "content": "3. The Proposed Method" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "spans": [ + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": "Problem definition. The goal of C-GCD is to have the offline trained model continually discover and learn novel object classes from unlabeled data containing both known and novel classes. We define a sequence of " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": " learning sessions " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "\\{S^0, S^1, \\dots, S^T\\}" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ". Let " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "x^t \\in \\mathcal{X}^t" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "y^t \\in \\mathcal{Y}^t" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": " denote the input and label space at session " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ". We represent each session as: " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "S^0 = \\{(\\mathbf{x}_i^0, \\mathbf{y}_i^0)\\}_{i=1}^{Z_0}" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "S^t = \\{(\\mathbf{x}_i^t)\\}_{i=1}^{Z_t}" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ". Note, only the first session (i.e., " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "t = 0" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ") contains large-scale labeled samples. As for " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "t > 0" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "S^t" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": " only contains unlabeled data. At the " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "t^{th}" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": " session, only " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "S^t" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": " is accessible, and the incoming data belongs to both learned known class from previous sessions and novel classes. Therefore, we can denote " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}^t = \\mathcal{Y}^{t-1} \\cup \\mathcal{Y}_n^t" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}_n^t" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": " represents the novel classes to be discovered at session " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ". After learning on " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "S^t" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ", the model is evaluated on all test images accumulated until session " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": " to test the performance on " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}^{t-1}" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": " (ideally the model should not forget old classes) and the discovery capability on " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}_n^t" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ". Compared with previous works [15, 11, 35, 45], C-GCD is much more challenging due to several factors. First, the unlabeled data contains both known and unknown classes, i.e., " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "\\mathcal{Y}^t = \\mathcal{Y}^{t-1} \\cup \\mathcal{Y}_n^t" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ". Second, labeled data is absent at " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "t > 0" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ", i.e., " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "S^0 \\cup S^t = \\emptyset" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "t > 0" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ". Finally, since C-GCD operates on a long horizon, i.e., " + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "inline_equation", + "content": "t \\gg 1" + }, + { + "bbox": [ + 304, + 186, + 547, + 472 + ], + "type": "text", + "content": ", the catastrophic forgetting issue is more severe." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 473, + 547, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 473, + 547, + 665 + ], + "spans": [ + { + "bbox": [ + 304, + 473, + 547, + 665 + ], + "type": "text", + "content": "Method overview. Fig. 2 shows an overview of MetaGCD. Following [40], we use a model without parametric classification heads since it is more suitable for dealing with novel classes. Novel class discovery is performed by directly clustering the feature spaces and class labels are assigned through the classic " + }, + { + "bbox": [ + 304, + 473, + 547, + 665 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 304, + 473, + 547, + 665 + ], + "type": "text", + "content": "-means algorithm. Concretely, we learn a model initialization using the labeled data during offline training. During each continual learning session, we update the model using a soft neighborhood contrastive learning (see Fig. 2 (a)) on unlabeled data. To fully exploit the labeled data in offline learning, we further develop a bilevel optimization based on meta-learning to simulate the online learning scenario, so that the model is ready to adapt to new incoming unlabeled data and discover novel objects after the offline training (see Fig. 2 (b)). In the following, we describe these two parts of our method in detail." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 305, + 671, + 545, + 685 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 671, + 545, + 685 + ], + "spans": [ + { + "bbox": [ + 305, + 671, + 545, + 685 + ], + "type": "text", + "content": "3.1. Contrastive learning based clustering network" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 689, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 547, + 715 + ], + "type": "text", + "content": "Considering the characteristics of labeled and unlabeled data, we employ different contrastive learning strategies. To" + } + ] + } + ], + "index": 10 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 758 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 758 + ], + "type": "text", + "content": "1657" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 100, + 72, + 492, + 208 + ], + "blocks": [ + { + "bbox": [ + 100, + 72, + 492, + 208 + ], + "lines": [ + { + "bbox": [ + 100, + 72, + 492, + 208 + ], + "spans": [ + { + "bbox": [ + 100, + 72, + 492, + 208 + ], + "type": "image", + "image_path": "9e89f4bcee28c996ca8261db3b804012b7177c25da688e497b7b2acd27352edf.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 100, + 209, + 494, + 373 + ], + "blocks": [ + { + "bbox": [ + 100, + 209, + 494, + 373 + ], + "lines": [ + { + "bbox": [ + 100, + 209, + 494, + 373 + ], + "spans": [ + { + "bbox": [ + 100, + 209, + 494, + 373 + ], + "type": "image", + "image_path": "23015a8311b36a9bf85e73d19f28bb88e2f63c7cbffc3d6cda72c6b0713fc6b0.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 384, + 545, + 443 + ], + "lines": [ + { + "bbox": [ + 46, + 384, + 545, + 443 + ], + "spans": [ + { + "bbox": [ + 46, + 384, + 545, + 443 + ], + "type": "text", + "content": "Figure 2: Overview of the proposed MetaGCD. (a) Our soft neighborhood contrastive learning network aims to discriminate uncorrelated instances while absorbing correlated instances to learn discriminative representations. (b) Our meta-learning optimization strategy utilizes the offline labeled data to simulate the testing incremental learning process by sampling sequential learning tasks. By learning from these sampled sequential tasks, our model learns a good initialization, so that it can effectively adapt to discover new novel classes without forgetting old classes." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 465, + 287, + 525 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 465, + 287, + 525 + ], + "spans": [ + { + "bbox": [ + 46, + 465, + 287, + 525 + ], + "type": "text", + "content": "train on the labeled data, we utilize a combination of unsupervised and supervised contrastive losses. When discovering the latent classes in continually encountered unlabeled data, we propose to mine soft positive neighbors for each data instance to elevate the discriminative feature learning." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 547, + 250, + 559 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 547, + 250, + 559 + ], + "spans": [ + { + "bbox": [ + 47, + 547, + 250, + 559 + ], + "type": "text", + "content": "3.1.1 Representation learning on labeled data" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 568, + 286, + 628 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 568, + 286, + 628 + ], + "spans": [ + { + "bbox": [ + 46, + 568, + 286, + 628 + ], + "type": "text", + "content": "To learn a robust and semantically meaningful representation on labeled data, we utilize both self-supervised [14] and supervised [22] contrastive losses. Let " + }, + { + "bbox": [ + 46, + 568, + 286, + 628 + ], + "type": "inline_equation", + "content": "\\mathbf{x}_i" + }, + { + "bbox": [ + 46, + 568, + 286, + 628 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 568, + 286, + 628 + ], + "type": "inline_equation", + "content": "\\mathbf{x}_i'" + }, + { + "bbox": [ + 46, + 568, + 286, + 628 + ], + "type": "text", + "content": " be two randomly augmented versions of " + }, + { + "bbox": [ + 46, + 568, + 286, + 628 + ], + "type": "inline_equation", + "content": "i^{th}" + }, + { + "bbox": [ + 46, + 568, + 286, + 628 + ], + "type": "text", + "content": " instance sample, the unsupervised contrastive loss is expressed as:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 86, + 639, + 287, + 666 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 86, + 639, + 287, + 666 + ], + "spans": [ + { + "bbox": [ + 86, + 639, + 287, + 666 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {i} ^ {u c l} = - \\log \\frac {\\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {i} ^ {\\prime} / \\tau\\right)}{\\sum_ {n} \\mathbb {I} _ {[ n \\neq i ]} \\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {n} / \\tau\\right)} \\tag {1}", + "image_path": "b395b803d8a58530904fb7cf16fa468159f725dc7392e770de5e2448af2d01f3.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_i = \\phi(f(\\mathbf{x}_i))" + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathbb{I}_{[n \\neq i]}" + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": " is an indicator function, and " + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\tau" + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": " is a temperature value. " + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": " is the feature extractor, and " + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\phi" + }, + { + "bbox": [ + 47, + 677, + 287, + 713 + ], + "type": "text", + "content": " is a multi-layer perceptron (MLP) projection head." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 465, + 539, + 477 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 465, + 539, + 477 + ], + "spans": [ + { + "bbox": [ + 317, + 465, + 539, + 477 + ], + "type": "text", + "content": "The supervised contrastive counterpart is expressed as:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 311, + 483, + 545, + 513 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 483, + 545, + 513 + ], + "spans": [ + { + "bbox": [ + 311, + 483, + 545, + 513 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {i} ^ {s c l} = - \\frac {1}{| \\mathcal {N} (i) |} \\sum_ {q \\in \\mathcal {N} (i)} \\log \\frac {\\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {q} / \\tau\\right)}{\\sum_ {n} \\mathbb {I} _ {[ n \\neq i ]} \\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {n} / \\tau\\right)} \\tag {2}", + "image_path": "b386f6bd6ede5bdb5c80e2366c21580bdd3692d118dde0643799c6ac57535e96.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 519, + 545, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 519, + 545, + 555 + ], + "spans": [ + { + "bbox": [ + 305, + 519, + 545, + 555 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 519, + 545, + 555 + ], + "type": "inline_equation", + "content": "\\mathcal{N}(i)" + }, + { + "bbox": [ + 305, + 519, + 545, + 555 + ], + "type": "text", + "content": " denotes the indices of instances having the same label as " + }, + { + "bbox": [ + 305, + 519, + 545, + 555 + ], + "type": "inline_equation", + "content": "\\mathbf{x}_i" + }, + { + "bbox": [ + 305, + 519, + 545, + 555 + ], + "type": "text", + "content": " within the batch. Finally, these two losses are weighted by " + }, + { + "bbox": [ + 305, + 519, + 545, + 555 + ], + "type": "inline_equation", + "content": "\\lambda" + }, + { + "bbox": [ + 305, + 519, + 545, + 555 + ], + "type": "text", + "content": " to train on the labeled data:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 341, + 561, + 545, + 586 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 341, + 561, + 545, + 586 + ], + "spans": [ + { + "bbox": [ + 341, + 561, + 545, + 586 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {l a b e l e d}} = (1 - \\lambda) \\sum_ {i \\in B} \\mathcal {L} _ {i} ^ {u c l} + \\lambda \\sum_ {i \\in B} \\mathcal {L} _ {i} ^ {s c l} \\tag {3}", + "image_path": "0a0b752e25a8e574ba01f08845a605ccc791a5b88dca18d9d3ca25ff5657cbd6.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 599, + 545, + 621 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 599, + 545, + 621 + ], + "spans": [ + { + "bbox": [ + 306, + 599, + 545, + 621 + ], + "type": "text", + "content": "3.1.2 Soft neighborhood contrastive learning on unlabeled data" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 629, + 545, + 713 + ], + "type": "text", + "content": "When learning on unlabeled data, only the unsupervised contrastive loss Eq. 1 can be used. However, the samples within the same class could be mistakenly treated as negatives due to the missing labels. In addition, the number of negative pairs significantly surpasses positive pairs. Such imbalanced loss contribution could be sub-optimal. Aligning the positive and negative pairs with the true classes" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1658" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 156 + ], + "type": "text", + "content": "emerges as a desired solution. [47] has attempted to address the limitations by mining more positive pairs in the neighbored of each data sample. However, the pseudo-positive pairs are treated equally, regardless of how close they are to that data sample. To address this issue, we propose to encode soft positive correlation among instance neighbors to achieve adaptive contribution, as shown in Fig. 2 (a)." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "spans": [ + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "text", + "content": "Specifically, for each " + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "inline_equation", + "content": "\\mathbf{x}_i" + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "text", + "content": ", we first use the nearest neighbor operator on the projected features to select candidate neighbors. We denote them as " + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "inline_equation", + "content": "NN(\\mathbf{z}_i)_k" + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "text", + "content": " as the index. We then pass them and " + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_i" + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "text", + "content": " to an attention module to predict a set of positiveness values " + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "inline_equation", + "content": "\\mathbf{w}_i = \\{w_{ik}\\} \\in (0,1)" + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "text", + "content": " to weight the contribution of " + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "inline_equation", + "content": "NN(\\mathbf{z}_i)_k" + }, + { + "bbox": [ + 46, + 156, + 288, + 240 + ], + "type": "text", + "content": " to the loss. Accordingly, the soft neighborhood contrastive loss is defined as:" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 246, + 291, + 287 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 246, + 291, + 287 + ], + "spans": [ + { + "bbox": [ + 47, + 246, + 291, + 287 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {i} ^ {\\text {s o f t}} = - \\frac {1}{| N N (\\mathbf {z} _ {i}) |} \\sum_ {k \\in N N (\\mathbf {z} _ {i})} \\log \\frac {w _ {i k} \\cdot \\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {k} / \\tau\\right)}{\\sum_ {n} \\mathbb {I} _ {[ n \\neq i ]} \\exp \\left(\\mathbf {z} _ {i} \\cdot \\mathbf {z} _ {n} / \\tau\\right)} \\tag {4}", + "image_path": "88885bc4ff99cb4895a7dbb55e85feaac03f4565b616783dc8edcadba598cd35.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 288, + 287, + 335 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 288, + 287, + 335 + ], + "spans": [ + { + "bbox": [ + 46, + 288, + 287, + 335 + ], + "type": "text", + "content": "Candidate neighborhood. For each batch of data, we first compute their features " + }, + { + "bbox": [ + 46, + 288, + 287, + 335 + ], + "type": "inline_equation", + "content": "\\mathcal{F}" + }, + { + "bbox": [ + 46, + 288, + 287, + 335 + ], + "type": "text", + "content": " from the projection head at once. For each reference view " + }, + { + "bbox": [ + 46, + 288, + 287, + 335 + ], + "type": "inline_equation", + "content": "\\mathbf{x}_i" + }, + { + "bbox": [ + 46, + 288, + 287, + 335 + ], + "type": "text", + "content": ", we retrieve nearest neighbors by comparing the cosine similarity to a threshold " + }, + { + "bbox": [ + 46, + 288, + 287, + 335 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 46, + 288, + 287, + 335 + ], + "type": "text", + "content": " as:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 71, + 342, + 287, + 357 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 342, + 287, + 357 + ], + "spans": [ + { + "bbox": [ + 71, + 342, + 287, + 357 + ], + "type": "interline_equation", + "content": "N N (\\mathbf {z} _ {i}) = \\{\\mathbf {F} \\}, \\text {f o r} \\mathbf {F} \\text {i n} \\mathcal {F}, \\text {i f} \\cos (\\mathbf {z} _ {i}, \\mathbf {F}) \\geq \\epsilon \\tag {5}", + "image_path": "f6e7b10b0f54779e7cdf6428de7f7dfa3d073034970a89e885b8c90c8d79a047.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 362, + 277, + 374 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 362, + 277, + 374 + ], + "spans": [ + { + "bbox": [ + 46, + 362, + 277, + 374 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 362, + 277, + 374 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_i" + }, + { + "bbox": [ + 46, + 362, + 277, + 374 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 362, + 277, + 374 + ], + "type": "inline_equation", + "content": "\\mathbf{F} \\in \\mathcal{F}" + }, + { + "bbox": [ + 46, + 362, + 277, + 374 + ], + "type": "text", + "content": " are normalized before computation." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 374, + 287, + 518 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 374, + 287, + 518 + ], + "spans": [ + { + "bbox": [ + 46, + 374, + 287, + 518 + ], + "type": "text", + "content": "Positiveness generation. Fig. 2 (a) shows an intuitive example of the candidate neighbors. The first two neighbors belong to the same category as the reference 'tiger' sample, while the " + }, + { + "bbox": [ + 46, + 374, + 287, + 518 + ], + "type": "inline_equation", + "content": "3^{rd}" + }, + { + "bbox": [ + 46, + 374, + 287, + 518 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 374, + 287, + 518 + ], + "type": "inline_equation", + "content": "4^{th}" + }, + { + "bbox": [ + 46, + 374, + 287, + 518 + ], + "type": "text", + "content": " neighbors are partially related (i.e., they belong to the 'lion' and 'leopard' categories, but not 'tiger'). The remaining instances are not related to 'tiger'. Therefore, the first four instances tend to be selected and they should contribute adaptively to the loss. We propose to learn an attention module to measure the soft correlations between the selected neighbors and the reference instance (instead of the binary form in [47]). Given two inputs " + }, + { + "bbox": [ + 46, + 374, + 287, + 518 + ], + "type": "inline_equation", + "content": "\\mathbf{z}_i" + }, + { + "bbox": [ + 46, + 374, + 287, + 518 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 374, + 287, + 518 + ], + "type": "inline_equation", + "content": "NN(\\mathbf{z}_i)_k" + }, + { + "bbox": [ + 46, + 374, + 287, + 518 + ], + "type": "text", + "content": ", we can calculate the positiveness score as:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 83, + 524, + 287, + 539 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 83, + 524, + 287, + 539 + ], + "spans": [ + { + "bbox": [ + 83, + 524, + 287, + 539 + ], + "type": "interline_equation", + "content": "\\mathbf {w} _ {i} = \\operatorname {S o f t m a x} \\left[ f _ {1} \\left(\\mathbf {z} _ {i}\\right) \\times f _ {2} \\left(N N \\left(\\mathbf {z} _ {i}\\right) _ {k}\\right) ^ {T} \\right] \\tag {6}", + "image_path": "67c7dff443be99f71de27ce01fa655861e9c5a30b4c9a934a7fffbb0d0ee088e.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "spans": [ + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "inline_equation", + "content": "f_{1}(\\cdot)" + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "inline_equation", + "content": "f_{2}(\\cdot)" + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "text", + "content": " are the new projection layers and " + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "inline_equation", + "content": "\\times" + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "text", + "content": " denotes the cross attention operator. Eq. 6 is then normalized so that " + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "inline_equation", + "content": "\\mathbf{w}_{i}" + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "text", + "content": " has a max value as 1. Note that " + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "inline_equation", + "content": "f_{1}(\\cdot)" + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "inline_equation", + "content": "f_{2}(\\cdot)" + }, + { + "bbox": [ + 46, + 544, + 287, + 653 + ], + "type": "text", + "content": " can also be the non-parametric identity mappings, which are empirically found to be more effective. This observation may be attributed to the self-supervised learning paradigm, where the objective is to train the encoder effectively. Simplifying the attention module leads to less overfitting and improves learning attentive features." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 659, + 284, + 673 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 659, + 284, + 673 + ], + "spans": [ + { + "bbox": [ + 47, + 659, + 284, + 673 + ], + "type": "text", + "content": "3.2. Learning to incrementally discover categories" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": "The main limitation of the prior works is that the labeled set " + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "inline_equation", + "content": "S^0" + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": " is not fully exploited [7]. Instead of performing only representation learning on " + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "inline_equation", + "content": "S^0" + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": " [21, 45], we borrow" + } + ] + } + ], + "index": 10 + }, + { + "type": "code", + "bbox": [ + 306, + 86, + 545, + 305 + ], + "blocks": [ + { + "bbox": [ + 306, + 72, + 529, + 84 + ], + "lines": [ + { + "bbox": [ + 306, + 72, + 529, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 529, + 84 + ], + "type": "text", + "content": "Algorithm 1 The optimization procedure of MetaGCD" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "code_caption" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "lines": [ + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "spans": [ + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": "Require: " + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "inline_equation", + "content": "\\alpha, \\beta, \\gamma" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": ": learning rates \nRequire: " + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "inline_equation", + "content": "S^0" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": ": training set of labeled classes \n1: randomly initialize parameters " + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": " \n2: while not converged do \n3: " + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "inline_equation", + "content": "\\mathcal{D} = \\left\\{\\left(\\mathcal{D}_{tr}^j,\\mathcal{D}_{te}^j\\right)\\right\\}_{j=0}^T" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": " \n4: ▷ sample a pseudo incremental sequence \n5: " + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "inline_equation", + "content": "\\mathcal{P} = \\emptyset" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": " ▷ empty cumulative pseudo test set \n6: " + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "inline_equation", + "content": "\\theta^{E,P}\\gets \\theta^{E,P} - \\gamma \\nabla_{\\theta^{E,P}}\\mathcal{L}_{labeled}(\\mathbf{x}_{tr}^0,\\mathbf{y}_{tr}^0;\\theta)" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": " \n7: ▷ update parameters using pseudo labeled classes \n8: " + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "inline_equation", + "content": "\\mathcal{P} = \\mathcal{P}\\cup \\mathcal{D}_{te}^{0}" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": " ▷ accumulate test set of sess-0 \n9: for " + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "inline_equation", + "content": "j = 1,\\dots,T" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": " do \n10: " + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "inline_equation", + "content": "\\tilde{\\theta}^{E,P} = \\theta^{E,P} - \\alpha \\nabla_{\\theta^{E,P}}\\mathcal{L}_{soft}(\\mathbf{x}_{tr}^j;\\theta)" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": " \n11: ▷ compute adapted params with unlabeled samples \n12: " + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "inline_equation", + "content": "\\mathcal{P} = \\mathcal{P}\\cup \\mathcal{D}_{te}^j" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": " ▷ accumulate test set of sess-j \n13: " + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "inline_equation", + "content": "\\theta \\gets \\theta -\\beta \\nabla_{\\theta}\\sum_{(\\mathcal{X},\\mathcal{Y})\\in \\mathcal{P}}\\mathcal{L}_{scl}(\\mathcal{X},\\mathcal{Y};\\tilde{\\theta}^E,\\tilde{\\theta}^P)" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": " \n15: ▷ update meta-params " + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 306, + 86, + 545, + 305 + ], + "type": "text", + "content": " to new session \n16: end for \n17: end while" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "code_body" + } + ], + "index": 12, + "sub_type": "algorithm" + }, + { + "bbox": [ + 304, + 330, + 547, + 474 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 330, + 547, + 474 + ], + "spans": [ + { + "bbox": [ + 304, + 330, + 547, + 474 + ], + "type": "text", + "content": "the meta-learning paradigm (in particular MAML [12]) to learn how to continually discover new classes. In few-shot learning, during meta-training, MAML constructs few-shot tasks to mimic the meta-testing scenario to achieve learning to quickly adapt. In our C-GCD case, the online continual class discovery tasks can be viewed as the \"meta-testing\" stage. Therefore, we propose to simulate the continual setting using " + }, + { + "bbox": [ + 304, + 330, + 547, + 474 + ], + "type": "inline_equation", + "content": "S^0" + }, + { + "bbox": [ + 304, + 330, + 547, + 474 + ], + "type": "text", + "content": " during offline training, as shown in Fig. 2 (b). We aim to produce a model initialization that is trained by aligning the training and evaluation objectives so that it is endowed with the capability to effectively discover novel classes with less forgetting during evaluation." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "spans": [ + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": "Sequential task sampling. To mimic the evaluation process, we sample sequential learning tasks from " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "\\mathcal{S}^0" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": " [7]. Specifically, we first randomly separate the " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "S^0" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": " into pseudo labeled and pseudo unlabeled classes without overlapping. Next, we sample a sequence of " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "T + 1" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": " sessions, " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "\\mathcal{D} = \\{(\\mathcal{D}_{tr}^j,\\mathcal{D}_{te}^j)\\}_{j = 0}^T" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{tr}^j" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{te}^j" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": " are the training and test set for the " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "j^{th}" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": " session. For the training splits " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "\\{\\mathcal{D}_{tr}^j\\}" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": ", we follow the evaluation protocol to only allow the first session to contain labeled data, (i.e., " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{tr}^0 = \\{\\mathbf{x}_{tr}^0,\\mathbf{y}_{tr}^0\\}" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": ") and the rest with unlabeled data (i.e., " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{tr}^j = \\{\\mathbf{x}_{tr}^j\\}" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": ", for " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "j > 0" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": "). We also set the first session to contain a larger number of samples, i.e., " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "\\left|\\mathcal{D}_{tr}^0\\right| \\gg \\left|\\mathcal{D}_{tr}^{j > 0}\\right|" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": " to simulate the C-GCD setting where the model is first trained during an offline training stage with a large amount of data. For the test splits " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "\\{\\mathcal{D}_{te}^j\\}" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": ", all of them contain labels that will be used during the optimization (i.e., " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{te}^j = \\{\\mathbf{x}_{te}^j,\\mathbf{y}_{te}^j\\}, \\forall j" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": "). Note that " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{te}^j" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": " only contains the test data belonging to the current session " + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "inline_equation", + "content": "j" + }, + { + "bbox": [ + 304, + 475, + 547, + 687 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "type": "text", + "content": "Meta-training. For each sampled sequence " + }, + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\mathcal{D}" + }, + { + "bbox": [ + 305, + 689, + 547, + 714 + ], + "type": "text", + "content": ", we let the model continually explore the incoming unlabeled data in" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1659" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "text", + "content": "an unsupervised manner. To reduce the forgetting issue due to learning new knowledge, we utilize the bi-level optimization [12, 8, 7] to directly formulate incrementally discovering without forgetting as the meta-objective. The meta-learning procedure is illustrated in Alg. 1 and Fig. 2 (b). Concretely, we decouple the network as " + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "inline_equation", + "content": "\\theta = \\{\\theta^{E},\\theta^{P}\\}" + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "inline_equation", + "content": "\\theta^{E}" + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "inline_equation", + "content": "\\theta^{P}" + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "text", + "content": " are the encoder and projection layers. At each incremental session, we aim to evaluate all the classes that have encountered so far. Hence, at the beginning of each sequence, we define an empty cumulative pseudo test set " + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "inline_equation", + "content": "\\mathcal{P}" + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "text", + "content": " to store the test samples from previous sessions. After that, we first train " + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "text", + "content": " on the pseudo labeled classes " + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "inline_equation", + "content": "(j = 0)" + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "text", + "content": " using the unsupervised and supervised contrastive loss (Eq. 3). At each " + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "inline_equation", + "content": "j^{th}" + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "text", + "content": " session " + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "inline_equation", + "content": "(j > 0)" + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "text", + "content": ", we update " + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "text", + "content": " on unlabeled samples " + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{tr}^{j} = \\{\\mathbf{x}_{tr}^{j}\\}" + }, + { + "bbox": [ + 46, + 72, + 289, + 253 + ], + "type": "text", + "content": " via a few gradient steps:" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 89, + 261, + 287, + 277 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 89, + 261, + 287, + 277 + ], + "spans": [ + { + "bbox": [ + 89, + 261, + 287, + 277 + ], + "type": "interline_equation", + "content": "\\tilde {\\theta} ^ {E, P} = \\theta^ {E, P} - \\alpha \\nabla_ {\\theta^ {E, P}} \\mathcal {L} _ {s o f t} (\\mathbf {x} _ {t r} ^ {j}; \\theta) \\tag {7}", + "image_path": "edb9ed1e5a11c1318ece4057cf9b576d1200a58e89646f6e8c102e0989097965.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 286, + 287, + 346 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 286, + 287, + 346 + ], + "spans": [ + { + "bbox": [ + 46, + 286, + 287, + 346 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 286, + 287, + 346 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{soft}(\\cdot)" + }, + { + "bbox": [ + 46, + 286, + 287, + 346 + ], + "type": "text", + "content": " is the proposed soft neighborhood contrastive loss (Eq. 4). It aims to discriminate uncorrelated samples while absorbing correlated ones. By thoroughly exploring the unlabeled data, it maintains comprehensive old knowledge while efficiently discovering novel classes." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 347, + 287, + 443 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 347, + 287, + 443 + ], + "spans": [ + { + "bbox": [ + 46, + 347, + 287, + 443 + ], + "type": "text", + "content": "Eq. 7 mimics how the model discovers novel classes on the incoming unlabeled data at test-time. Ideally, we like the adapted " + }, + { + "bbox": [ + 46, + 347, + 287, + 443 + ], + "type": "inline_equation", + "content": "\\tilde{\\theta}^{E,P}" + }, + { + "bbox": [ + 46, + 347, + 287, + 443 + ], + "type": "text", + "content": " to perform well on all encountered classes. The test data from previous sessions and the current session separately reflect the catastrophic forgetting robustness and novel class discovery capability. Thus, we append " + }, + { + "bbox": [ + 46, + 347, + 287, + 443 + ], + "type": "inline_equation", + "content": "\\mathcal{D}_{te}^{j}" + }, + { + "bbox": [ + 46, + 347, + 287, + 443 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 347, + 287, + 443 + ], + "type": "inline_equation", + "content": "\\mathcal{P}" + }, + { + "bbox": [ + 46, + 347, + 287, + 443 + ], + "type": "text", + "content": ". Accordingly, the meta-objective is defined as follows for the outer loop of the meta-level optimization:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 89, + 453, + 287, + 474 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 89, + 453, + 287, + 474 + ], + "spans": [ + { + "bbox": [ + 89, + 453, + 287, + 474 + ], + "type": "interline_equation", + "content": "\\min _ {\\theta^ {E}, \\theta^ {P}} \\sum_ {(\\mathcal {X}, \\mathcal {Y}) \\in \\mathcal {P}} \\mathcal {L} _ {s c l} (\\mathcal {X}, \\mathcal {Y}; \\tilde {\\theta} ^ {E}, \\tilde {\\theta} ^ {P}) \\tag {8}", + "image_path": "6ce73ee296e616535eab3a31948b57f8fb0c3ec686e02a92386ae33642014b4c.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "spans": [ + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{scl}(\\cdot)" + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "text", + "content": " is the supervised contrastive loss in Eq. 1. Note that the optimization is performed on " + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "text", + "content": ", although " + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{scl}(\\cdot)" + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "text", + "content": " is a function of " + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "inline_equation", + "content": "\\tilde{\\theta}^E" + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "inline_equation", + "content": "\\tilde{\\theta}^P" + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "text", + "content": ". The meta-objective in Eq. 8 is then optimized using gradient descent, as shown in Line 13 of Alg. 1. We empty " + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "inline_equation", + "content": "\\mathcal{P}" + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "text", + "content": " when all " + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "inline_equation", + "content": "T + 1" + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "text", + "content": " sessions are iterated. After meta-training, we obtain an initialization of the model " + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 485, + 287, + 581 + ], + "type": "text", + "content": " which has been specifically trained to discover and learn novel objects from a sequence of unlabeled data." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 582, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 287, + 714 + ], + "type": "text", + "content": "Meta-testing. It is worth mentioning that the procedure in Alg. 1 aligns with the evaluation protocol. After discovering novel classes at each incremental session, the model is evaluated on all encountered classes. Our meta-objective optimizes the model towards what it is supposed to do at evaluation to maximize the performance. In addition, despite some uncertainties that may occur for unsupervised learning, the model is constrained by a fully supervised meta-objective. Thus, when training converges, the meta-model " + }, + { + "bbox": [ + 46, + 582, + 287, + 714 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 46, + 582, + 287, + 714 + ], + "type": "text", + "content": " is ready to discover novel classes while maintaining the old knowledge by only running Line 10 of Alg. 1." + } + ] + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 312, + 71, + 541, + 139 + ], + "blocks": [ + { + "bbox": [ + 312, + 71, + 541, + 139 + ], + "lines": [ + { + "bbox": [ + 312, + 71, + 541, + 139 + ], + "spans": [ + { + "bbox": [ + 312, + 71, + 541, + 139 + ], + "type": "table", + "html": "
DatasetLabeled SetUnlabeled Set
#class#image#class#image
CIFAR107280001022000
CIFAR100803200010018000
Tiny-ImageNet1506000020040000
", + "image_path": "98d8be3ab01e70657792e025a12bcd0abb27bcbd281b48741afebfd1d49bb5e0.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 305, + 147, + 547, + 183 + ], + "lines": [ + { + "bbox": [ + 305, + 147, + 547, + 183 + ], + "spans": [ + { + "bbox": [ + 305, + 147, + 547, + 183 + ], + "type": "text", + "content": "Table 1: Datasets used in our experiments. We show the number of classes in the labeled and unlabeled sets, as well as the number of samples." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 203, + 388, + 217 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 203, + 388, + 217 + ], + "spans": [ + { + "bbox": [ + 306, + 203, + 388, + 217 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 222, + 411, + 235 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 222, + 411, + 235 + ], + "spans": [ + { + "bbox": [ + 306, + 222, + 411, + 235 + ], + "type": "text", + "content": "4.1. Dataset and setup" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 240, + 545, + 348 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 240, + 545, + 348 + ], + "spans": [ + { + "bbox": [ + 304, + 240, + 545, + 348 + ], + "type": "text", + "content": "Dataset. We construct the C-GCD benchmark using three widely used datasets as in NCD [40, 35, 47], i.e., CIFAR10 [23], CIFAR100 [23] and Tiny-ImageNet [25]. Each dataset is split into two subsets, 1) large-scale labeled samples accounting for " + }, + { + "bbox": [ + 304, + 240, + 545, + 348 + ], + "type": "inline_equation", + "content": "80\\%" + }, + { + "bbox": [ + 304, + 240, + 545, + 348 + ], + "type": "text", + "content": " of the known classes data constitute a labeled set for offline training; and 2) the remaining data containing known and novel classes are used as an unlabeled set for continual object discovery. In Tab. 1, we summarize the dataset splits used in our training." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "spans": [ + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "text", + "content": "Session-wise data split. All labeled samples " + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "inline_equation", + "content": "S^0" + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "text", + "content": " are used for offline training in our setting. During the online incremental learning stage, the unlabeled samples are dynamically added (i.e., sessions " + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "inline_equation", + "content": "t \\geq 1" + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "text", + "content": "). Specifically, CIFAR10 is divided into 3 incremental sessions. In the " + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "inline_equation", + "content": "t^{th}(t > 0)" + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "text", + "content": " session, 3000 unlabeled images from 1 novel class and 2000 unlabeled images from " + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "inline_equation", + "content": "7 + (t - 1) \\times 1" + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "text", + "content": " known classes are added. CIFAR100 is divided into 4 sessions, in which 1500 unlabeled images from 5 novel classes and 2000 unlabeled images from " + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "inline_equation", + "content": "80 + (t - 1) \\times 5" + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "text", + "content": " known classes are added in the " + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "inline_equation", + "content": "t^{th}" + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "text", + "content": " session. The Tiny-ImageNet consists of 5 incremental sessions, each containing 3000 unlabeled images from 10 novel classes and 3000 unlabeled images from " + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "inline_equation", + "content": "150 + (t - 1) \\times 10" + }, + { + "bbox": [ + 304, + 348, + 546, + 515 + ], + "type": "text", + "content": " known classes." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 516, + 547, + 635 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 516, + 547, + 635 + ], + "spans": [ + { + "bbox": [ + 304, + 516, + 547, + 635 + ], + "type": "text", + "content": "Sequential task sampling. During offline training, we use " + }, + { + "bbox": [ + 304, + 516, + 547, + 635 + ], + "type": "inline_equation", + "content": "S^0" + }, + { + "bbox": [ + 304, + 516, + 547, + 635 + ], + "type": "text", + "content": " to sample sequential tasks. We first split " + }, + { + "bbox": [ + 304, + 516, + 547, + 635 + ], + "type": "inline_equation", + "content": "S^0" + }, + { + "bbox": [ + 304, + 516, + 547, + 635 + ], + "type": "text", + "content": " into non-overlapping pseudo labeled and novel classes (4/3 for CIFAR10, 60/20 for CIFAR100 and 100/50 for TinyImageNet). For each task, the pseudo labeled set is first used to warm up the model, followed by " + }, + { + "bbox": [ + 304, + 516, + 547, + 635 + ], + "type": "inline_equation", + "content": "T" + }, + { + "bbox": [ + 304, + 516, + 547, + 635 + ], + "type": "text", + "content": " incremental sessions of unlabeled samples containing the pseudo labeled and novel classes. Both the session number and the number of novel classes in each offline incremental session are consistent with the online incremental learning scenario." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 635, + 547, + 684 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 635, + 547, + 684 + ], + "spans": [ + { + "bbox": [ + 304, + 635, + 547, + 684 + ], + "type": "text", + "content": "Evaluation metrics. After learning the model on unlabeled samples at every online incremental stage, we follow [40] to measure the clustering accuracy between the ground truth labels " + }, + { + "bbox": [ + 304, + 635, + 547, + 684 + ], + "type": "inline_equation", + "content": "y_{i}" + }, + { + "bbox": [ + 304, + 635, + 547, + 684 + ], + "type": "text", + "content": " and the model's predictions " + }, + { + "bbox": [ + 304, + 635, + 547, + 684 + ], + "type": "inline_equation", + "content": "\\hat{y}_{i}" + }, + { + "bbox": [ + 304, + 635, + 547, + 684 + ], + "type": "text", + "content": " as:" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 342, + 690, + 545, + 715 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 342, + 690, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 342, + 690, + 545, + 715 + ], + "type": "interline_equation", + "content": "A C C = \\max _ {p \\in \\mathcal {P} (\\mathcal {Y})} \\frac {1}{N} \\sum \\left(\\mathbb {1} \\left\\{y _ {i} = p \\left(\\hat {y} _ {i}\\right) \\right\\}\\right), \\tag {9}", + "image_path": "698226df94090400759100a8c3dd9df63b4691bed75c29a698446915762f3b0d.jpg" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1660" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 70, + 545, + 358 + ], + "blocks": [ + { + "bbox": [ + 50, + 70, + 545, + 358 + ], + "lines": [ + { + "bbox": [ + 50, + 70, + 545, + 358 + ], + "spans": [ + { + "bbox": [ + 50, + 70, + 545, + 358 + ], + "type": "table", + "html": "
MethodsCIFAR10 (Session Number)Final\nImpro.
123
AllOldNewAllOldNewAllOldNewAllOldNewAllOldNew
RankStats69.3170.2058.6365.2367.8651.2038.1650.0135.94+54.50+47.22+48.77
FRoST73.9281.1766.4569.5679.7358.0467.7370.8451.13+24.93+26.39+33.58
VanillaGCD89.2497.9781.8085.1396.6774.6086.4195.0376.75+6.25+2.20+7.96
GM90.0098.4177.4087.3999.0173.4687.8697.1578.93+4.80+0.08+5.78
MetaGCD(ours)95.3899.0789.1593.3498.8185.3992.6697.2384.71
MethodsCIFAR100 (Session Number)Final\nImpro.
1234
AllOldNewAllOldNewAllOldNewAllOldNewAllOldNew
RankStats62.3364.2231.6055.0158.5526.8551.7756.7025.4747.5154.5917.20+27.05+23.01+43.93
FRoST67.1468.5750.7367.0168.8252.6062.3565.4845.6755.8459.0642.95+18.72+18.54+18.18
VanillaGCD76.7877.9158.6073.6775.2960.7072.7774.7262.3371.4474.7558.20+3.12+2.85+2.93
GM78.2979.9166.0077.5879.6461.1374.5677.6058.1472.0275.9856.32+2.54+1.62+4.81
MetaGCD(ours)78.9679.3672.6078.6779.4166.8176.0678.2064.8774.5677.6061.13
MethodsTiny-ImageNet (Session Number)Final\nImpro.
1234
AllOldNewAllOldNewAllOldNewAllOldNewAllOldNew
RankStats62.3964.5435.0155.8952.2334.2049.8846.1728.3344.2042.8724.5036.0935.2015.76
FRoST64.9267.8446.2859.5061.8640.6057.8660.6339.1455.6859.7136.5550.4953.7633.37
VanillaGCD75.9278.1762.1574.5377.7356.1273.6474.8557.3170.6971.1354.3566.1567.1754.43
GM76.3279.5563.6075.4378.1057.4072.6376.2954.8070.5476.8051.5067.3172.0850.90
MetaGCD(ours)78.6779.4166.8077.8979.9561.4075.2377.8661.2072.0075.6157.5570.2471.5358.46
", + "image_path": "9638602ac314513ff3e5b49e7ce60efec97a91793da539da334c8184ad79a889.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 367, + 546, + 392 + ], + "lines": [ + { + "bbox": [ + 46, + 367, + 546, + 392 + ], + "spans": [ + { + "bbox": [ + 46, + 367, + 546, + 392 + ], + "type": "text", + "content": "Table 2: Performance (in %) comparisons with the state-of-the-art methods on CIFAR10, CIFAR100, Tiny-ImageNet datasets. The results of other methods are obtained by running their released codes under the C-GCD setting." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 413, + 288, + 534 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 413, + 288, + 534 + ], + "spans": [ + { + "bbox": [ + 46, + 413, + 288, + 534 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 413, + 288, + 534 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 46, + 413, + 288, + 534 + ], + "type": "text", + "content": " is the total number of test samples and " + }, + { + "bbox": [ + 46, + 413, + 288, + 534 + ], + "type": "inline_equation", + "content": "\\mathcal{P}(\\mathcal{V})" + }, + { + "bbox": [ + 46, + 413, + 288, + 534 + ], + "type": "text", + "content": " is the set of all permutations of the class labels " + }, + { + "bbox": [ + 46, + 413, + 288, + 534 + ], + "type": "inline_equation", + "content": "\\mathcal{V}" + }, + { + "bbox": [ + 46, + 413, + 288, + 534 + ], + "type": "text", + "content": " encountered so far. The optimal permutation can be obtained via the Hungarian algorithm [24]. Our main metric is ACC on 'All' classes, indicating the accuracy across all accumulated test sets so far. To decouple the evaluation on forgetting and discovery, we further report accuracy for both the 'Old' classes subset (samples in the test set belonging to previous known classes) and 'New' classes subset (samples in the test set belonging to novel classes)." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "type": "text", + "content": "Implementation details. Following [40], we employ a vision transformer (ViT-B-16) [10] pretrained on ImageNet [9] with DINO [3] as the feature extractor throughout the paper. We use the Adam optimizer and the learning rates in Alg. 1 are set as " + }, + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\gamma = 0.1" + }, + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\alpha = 0.001" + }, + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\beta = 0.0001" + }, + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "type": "text", + "content": ". We use a batch size of 256 and " + }, + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\lambda = 0.35" + }, + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "type": "text", + "content": " to balance the losses in Eq. 3. Unless otherwise stated, we select the threshold " + }, + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 46, + 545, + 288, + 715 + ], + "type": "text", + "content": " to be 0.85 in Eq. 5. At the meta-training stage, we first perform training on pseudo labeled set for 50 epochs, followed by 10 inner and 1 outer gradient updates for incremental sessions. At the meta-test stage, we directly perform 20 gradient updates to adapt using unlabeled samples. Furthermore, we follow standard practice in self-supervised learning to use the same projection head as in [3] and discard it at test-time." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 305, + 412, + 501, + 426 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 412, + 501, + 426 + ], + "spans": [ + { + "bbox": [ + 305, + 412, + 501, + 426 + ], + "type": "text", + "content": "4.2. Comparison with the state-of-the-art" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 434, + 545, + 615 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 434, + 545, + 615 + ], + "spans": [ + { + "bbox": [ + 304, + 434, + 545, + 615 + ], + "type": "text", + "content": "Since this paper considers a new problem setting, there is no prior work that we can directly compare. Nevertheless, we choose SOTA methods on NCD and run their codes under our C-GCD setting, including RankStats [16], VanillaGCD [40], and recent continual NCD models FRoST [35], GM [45]. Both RankStats and FRoST train two classifiers on top of a shared feature representation. The first head is fed images from the labeled set and is trained with the cross-entropy loss, while the second head sees only images from unlabeled images of novel classes. In order to adapt RankStats and FRoST to C-GCD, we train them with a single classification head for the total number of classes in the dataset. The sequential version of VanillaGCD is adopted and serves as the baseline for our model. We leverage the original training mechanism for GM." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 617, + 546, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 617, + 546, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 617, + 546, + 715 + ], + "type": "text", + "content": "In Tab. 2, we report the All/Old/New class accuracy per incremental session for all methods, and the relative improvement for the final session. As we can see, the proposed method consistently outperforms all other methods on all three datasets among the most incremental sessions. Specifically, our MetaGCD surpasses the most recent method GM by " + }, + { + "bbox": [ + 304, + 617, + 546, + 715 + ], + "type": "inline_equation", + "content": "5.78\\%" + }, + { + "bbox": [ + 304, + 617, + 546, + 715 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 617, + 546, + 715 + ], + "type": "inline_equation", + "content": "4.81\\%" + }, + { + "bbox": [ + 304, + 617, + 546, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 617, + 546, + 715 + ], + "type": "inline_equation", + "content": "7.56\\%" + }, + { + "bbox": [ + 304, + 617, + 546, + 715 + ], + "type": "text", + "content": " on CIFAR10, CIFAR100 and Tiny-ImageNet datasets for the final New classes accuracy." + } + ] + } + ], + "index": 6 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 314, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 314, + 758 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 314, + 758 + ], + "type": "text", + "content": "1661" + } + ] + } + ], + "index": 7 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 50, + 71, + 545, + 163 + ], + "blocks": [ + { + "bbox": [ + 50, + 71, + 545, + 163 + ], + "lines": [ + { + "bbox": [ + 50, + 71, + 545, + 163 + ], + "spans": [ + { + "bbox": [ + 50, + 71, + 545, + 163 + ], + "type": "table", + "html": "
MethodsCIFAR100 (Session Number)Average Acc
1234
AllOldNewAllOldNewAllOldNewAllOldNewmAmOmN
Baseline76.7877.9158.6073.6775.2960.7072.7774.6262.3371.4474.7558.2073.6775.6459.96
+LCN77.2978.5365.4475.2077.6763.0874.5575.9163.6372.6275.4359.4074.9276.8962.89
+LSP77.9278.4568.7876.5378.2264.7174.8677.2464.0973.3476.8760.6075.6677.7064.55
+Meta-learning78.9679.3672.6078.6779.4166.8176.0678.2064.8774.5677.6061.1377.0678.6466.35
", + "image_path": "610ff98fda1c4ad753c53e187dffc9b9c6bb80ec78ff22f1d01cede7029291a4.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 171, + 546, + 208 + ], + "lines": [ + { + "bbox": [ + 46, + 171, + 546, + 208 + ], + "spans": [ + { + "bbox": [ + 46, + 171, + 546, + 208 + ], + "type": "text", + "content": "Table 3: Ablation study of various components of our MetaGCD on the CIFAR100 dataset. We report 'All', 'Old' and 'New' class accuracy for each incremental session, and the average of all sessions such as mean 'All' (mA), mean 'Old' (mO) and mean 'New' accuracy (mN). Here CN denotes candidate neighbors and SP denotes soft positiveness." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "type": "image", + "bbox": [ + 50, + 238, + 164, + 349 + ], + "blocks": [ + { + "bbox": [ + 50, + 238, + 164, + 349 + ], + "lines": [ + { + "bbox": [ + 50, + 238, + 164, + 349 + ], + "spans": [ + { + "bbox": [ + 50, + 238, + 164, + 349 + ], + "type": "image", + "image_path": "087bc3da845b31f71935cb67300089dcd2710b6c820598ba73aedbda46680128.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 359, + 287, + 431 + ], + "lines": [ + { + "bbox": [ + 46, + 359, + 287, + 431 + ], + "spans": [ + { + "bbox": [ + 46, + 359, + 287, + 431 + ], + "type": "text", + "content": "Figure 3: Class-wise performance on the CIFAR100 dataset. The confusion matrices show that our model significantly improves the baseline for both known and novel classes (separated by the red line). Especially for novel classes, the confusion matrix of our method has more concentrated values along the diagonal." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 167, + 239, + 286, + 349 + ], + "blocks": [ + { + "bbox": [ + 167, + 239, + 286, + 349 + ], + "lines": [ + { + "bbox": [ + 167, + 239, + 286, + 349 + ], + "spans": [ + { + "bbox": [ + 167, + 239, + 286, + 349 + ], + "type": "image", + "image_path": "635d80b87485e79afe54aa9a4c11cc66317cc68604c8c9e9969f87f7a21af487.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 316, + 546, + 376 + ], + "lines": [ + { + "bbox": [ + 305, + 316, + 546, + 376 + ], + "spans": [ + { + "bbox": [ + 305, + 316, + 546, + 376 + ], + "type": "text", + "content": "Figure 4: Hyper-parameter analysis on the CIFAR100 dataset regarding feature similarity threshold (left) and various numbers of novel classes (right). An appropriate threshold or the number of new classes helps to stabilize the training process and improve performance." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 455, + 287, + 551 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 455, + 287, + 551 + ], + "spans": [ + { + "bbox": [ + 46, + 455, + 287, + 551 + ], + "type": "text", + "content": "Besides, our model outperforms the baseline VanillaGCD by " + }, + { + "bbox": [ + 46, + 455, + 287, + 551 + ], + "type": "inline_equation", + "content": "6.25\\%" + }, + { + "bbox": [ + 46, + 455, + 287, + 551 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 455, + 287, + 551 + ], + "type": "inline_equation", + "content": "3.12\\%" + }, + { + "bbox": [ + 46, + 455, + 287, + 551 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 455, + 287, + 551 + ], + "type": "inline_equation", + "content": "4.09\\%" + }, + { + "bbox": [ + 46, + 455, + 287, + 551 + ], + "type": "text", + "content": " for the final All classes. We also report the class-wise performance via the confusion matrices shown in Fig. 3. It is obvious that the baseline performs poorly, especially on the novel classes. However, the proposed model has a significant gain in discovering novel classes. Moreover, less forgetting is observed in our method, as more values are concentrated on the diagonal." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 561, + 141, + 574 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 561, + 141, + 574 + ], + "spans": [ + { + "bbox": [ + 47, + 561, + 141, + 574 + ], + "type": "text", + "content": "4.3. Ablation Study" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 580, + 287, + 604 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 580, + 287, + 604 + ], + "spans": [ + { + "bbox": [ + 46, + 580, + 287, + 604 + ], + "type": "text", + "content": "We conduct ablation studies on the CIFAR100 dataset to evaluate each component in our proposed framework." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "content": "Importance of neighborhood. In our contrastive learning framework, we compute the soft correlation to allow more positive pairs to contribute to the loss. As reported in the second row of Tab. 3, considering the neighborhood achieves a performance gain of " + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "inline_equation", + "content": "1.25\\%" + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "content": " (i.e., " + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "inline_equation", + "content": "74.92\\%" + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "content": " v.s. " + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "inline_equation", + "content": "73.67\\%" + }, + { + "bbox": [ + 46, + 605, + 287, + 714 + ], + "type": "text", + "content": " on the mean accuracy of All classes). The performance gain may come from the abundant comparisons from positive samples, which facilitates the current instance to align with more highly-correlated samples. We also conduct" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 310, + 236, + 541, + 308 + ], + "blocks": [ + { + "bbox": [ + 310, + 236, + 541, + 308 + ], + "lines": [ + { + "bbox": [ + 310, + 236, + 541, + 308 + ], + "spans": [ + { + "bbox": [ + 310, + 236, + 541, + 308 + ], + "type": "image", + "image_path": "92c7e533a3ce878c8b9505e8443b862ea114e97d3b7ae0fc0befb26766ed9c82.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 400, + 545, + 496 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 400, + 545, + 496 + ], + "spans": [ + { + "bbox": [ + 304, + 400, + 545, + 496 + ], + "type": "text", + "content": "experiments to assess the sensitivity of threshold " + }, + { + "bbox": [ + 304, + 400, + 545, + 496 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 304, + 400, + 545, + 496 + ], + "type": "text", + "content": " when selecting the positive neighbor instances. Increasing " + }, + { + "bbox": [ + 304, + 400, + 545, + 496 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 304, + 400, + 545, + 496 + ], + "type": "text", + "content": " allows more strict positive pairs, but some partially related samples might be ignored. On the other hand, reducing " + }, + { + "bbox": [ + 304, + 400, + 545, + 496 + ], + "type": "inline_equation", + "content": "\\epsilon" + }, + { + "bbox": [ + 304, + 400, + 545, + 496 + ], + "type": "text", + "content": " increases the likelihood of introducing true negative samples, which may negatively impact model performance. As empirically found in the left side of Fig. 4, a trade-off should be made, and a threshold of 0.85 achieves the best performance." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 497, + 546, + 676 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 497, + 546, + 676 + ], + "spans": [ + { + "bbox": [ + 304, + 497, + 546, + 676 + ], + "type": "text", + "content": "Importance of soft positiveness. We then analyze the importance of soft positiveness to the recognition performance in the third row of Tab. 3. When we compute a correlation weight for each selected neighbor, the clustering accuracy on Novel classes increases from " + }, + { + "bbox": [ + 304, + 497, + 546, + 676 + ], + "type": "inline_equation", + "content": "62.89\\%" + }, + { + "bbox": [ + 304, + 497, + 546, + 676 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 304, + 497, + 546, + 676 + ], + "type": "inline_equation", + "content": "64.55\\%" + }, + { + "bbox": [ + 304, + 497, + 546, + 676 + ], + "type": "text", + "content": ". It indicates that the binary labeling strategy is insufficient to measure the correlation at the feature space, thus causing the backbone network to produce less discriminative representations compared with soft labeling methods. In the lower part of Fig. 2 (a), we show the correlation weight of selected neighbors with an input instance. The high score corresponds to the same category while the low score corresponds to less-correlated categories, which shows that our attention module is effective in modeling correlations between the input instance and each candidate neighbor." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 677, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 677, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 305, + 677, + 545, + 712 + ], + "type": "text", + "content": "Effectiveness of meta-learning. Our meta-learning optimization strategy further improves All classes accuracy to " + }, + { + "bbox": [ + 305, + 677, + 545, + 712 + ], + "type": "inline_equation", + "content": "74.56\\%" + }, + { + "bbox": [ + 305, + 677, + 545, + 712 + ], + "type": "text", + "content": " for the final incremental session in the last row" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1662" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 205 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 205 + ], + "type": "text", + "content": "of Tab. 3. It demonstrates the effectiveness of the proposed method where the meta-objective specifically forces the model to discover novel classes without forgetting old classes. Additionally, we analyze the impact of the number of novel classes that are sampled during meta-training. To investigate this, we train separate models by setting the number of novel classes in the range of " + }, + { + "bbox": [ + 46, + 72, + 289, + 205 + ], + "type": "inline_equation", + "content": "\\{1, 10\\}" + }, + { + "bbox": [ + 46, + 72, + 289, + 205 + ], + "type": "text", + "content": ". As illustrated on the right side of Fig. 4, a larger number of classes for sequence tasks is more optimal. When there are fewer classes, the model is at a higher risk of overfitting to certain classes rather than learning how to incrementally learn." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 215, + 119, + 227 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 215, + 119, + 227 + ], + "spans": [ + { + "bbox": [ + 47, + 215, + 119, + 227 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 236, + 289, + 368 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 236, + 289, + 368 + ], + "spans": [ + { + "bbox": [ + 46, + 236, + 289, + 368 + ], + "type": "text", + "content": "In this paper, we propose a more realistic setting for real-world applications, namely C-GCD. The ultimate goal of C-GCD is to discover novel classes while keeping the old knowledge without forgetting. We propose a meta-learning based optimization strategy to directly optimize the network to learn how to incrementally discover with less forgetting. In addition, we introduce a soft neighborhood contrastive learning to utilize the soft positiveness to adaptively support the current instances from their neighbors. Extensive experiments on three datasets demonstrate the superiority of our method over state-of-the-art methods." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 378, + 157, + 392 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 378, + 157, + 392 + ], + "spans": [ + { + "bbox": [ + 47, + 378, + 157, + 392 + ], + "type": "text", + "content": "6. Acknowledgments" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 398, + 287, + 447 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 398, + 287, + 447 + ], + "spans": [ + { + "bbox": [ + 47, + 398, + 287, + 447 + ], + "type": "text", + "content": "This work was supported by the Fundamental Research Funds for the Central Universities (No. 2022JBZY019), the National Key Research and Development Project (No. 2018AAA0100300) and an NSERC Discovery grant." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 457, + 107, + 470 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 457, + 107, + 470 + ], + "spans": [ + { + "bbox": [ + 48, + 457, + 107, + 470 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 477, + 288, + 714 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 53, + 477, + 287, + 521 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 477, + 287, + 521 + ], + "spans": [ + { + "bbox": [ + 53, + 477, + 287, + 521 + ], + "type": "text", + "content": "[1] Philip Bachman, R Devon Hjelm, and William Buchwalter. Learning representations by maximizing mutual information across views. Advances in Neural Information Processing Systems, 32, 2019." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 522, + 287, + 566 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 522, + 287, + 566 + ], + "spans": [ + { + "bbox": [ + 53, + 522, + 287, + 566 + ], + "type": "text", + "content": "[2] Peyman Bateni, Raghav Goyal, Vaden Masrani, Frank Wood, and Leonid Sigal. Improved few-shot visual classification. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 14493-14502, 2020." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 567, + 288, + 621 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 567, + 288, + 621 + ], + "spans": [ + { + "bbox": [ + 53, + 567, + 288, + 621 + ], + "type": "text", + "content": "[3] Mathilde Caron, Hugo Touvron, Ishan Misra, Hervé Jégou, Julien Mairal, Piotr Bojanowski, and Armand Joulin. Emerging properties in self-supervised vision transformers. In Proceedings of the IEEE International Conference on Computer Vision, pages 9650-9660, 2021." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 624, + 287, + 656 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 624, + 287, + 656 + ], + "spans": [ + { + "bbox": [ + 53, + 624, + 287, + 656 + ], + "type": "text", + "content": "[4] Can Chen, Yingxueff Zhang, Jie Fu, Xue Steve Liu, and Mark Coates. Bidirectional learning for offline infinite-width model-based optimization. NeurIPS, 2022." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 53, + 658, + 287, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 658, + 287, + 690 + ], + "spans": [ + { + "bbox": [ + 53, + 658, + 287, + 690 + ], + "type": "text", + "content": "[5] Can Chen, Shuhao Zheng, Xi Chen, Erqun Dong, Xue Steve Liu, Hao Liu, and Dejing Dou. Generalized dataweighting via class-level gradient manipulation. NeurIPS, 2021." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 53, + 692, + 287, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 692, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 53, + 692, + 287, + 714 + ], + "type": "text", + "content": "[6] Ting Chen, Simon Kornblith, Mohammad Norouzi, and Geoffrey Hinton. A simple framework for contrastive learning" + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 547, + 714 + ], + "type": "list", + "angle": 0, + "index": 26, + "blocks": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 326, + 73, + 545, + 106 + ], + "type": "text", + "content": "of visual representations. In Proceedings of the IEEE International Conference on Machine Learning, pages 1597-1607, 2020." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 312, + 106, + 547, + 161 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 106, + 547, + 161 + ], + "spans": [ + { + "bbox": [ + 312, + 106, + 547, + 161 + ], + "type": "text", + "content": "[7] Zhixiang Chi, Li Gu, Huan Liu, Yang Wang, Yuanhao Yu, and Jin Tang. Meta-scl: A meta-learning approach for few-shot class incremental learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, pages 14166-14175, 2022." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 312, + 162, + 545, + 215 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 162, + 545, + 215 + ], + "spans": [ + { + "bbox": [ + 312, + 162, + 545, + 215 + ], + "type": "text", + "content": "[8] Zhixiang Chi, Yang Wang, Yuanhao Yu, and Jin Tang. Test-time fast adaptation for dynamic scene deblurring via meta-auxiliary learning. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 9137-9146, 2021." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 312, + 217, + 545, + 261 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 312, + 217, + 545, + 261 + ], + "spans": [ + { + "bbox": [ + 312, + 217, + 545, + 261 + ], + "type": "text", + "content": "[9] Jia Deng, Wei Dong, Richard Socher, Li-Jia Li, Kai Li, and Li Fei-Fei. Imagenet: A large-scale hierarchical image database. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 248-255, 2009." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 261, + 547, + 337 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 261, + 547, + 337 + ], + "spans": [ + { + "bbox": [ + 308, + 261, + 547, + 337 + ], + "type": "text", + "content": "[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. In Proceedings of the IEEE International Conference on Learning Representations, 2021." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 338, + 545, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 338, + 545, + 392 + ], + "spans": [ + { + "bbox": [ + 308, + 338, + 545, + 392 + ], + "type": "text", + "content": "[11] Enrico Fini, Enver Sangineto, Stéphane Lathuilière, Zhun Zhong, Moin Nabi, and Elisa Ricci. A unified objective for novel class discovery. In Proceedings of the IEEE International Conference on Computer Vision, pages 9284-9292, 2021." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 393, + 545, + 437 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 393, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 308, + 393, + 545, + 437 + ], + "type": "text", + "content": "[12] Chelsea Finn, Pieter Abbeel, and Sergey Levine. Model-agnostic meta-learning for fast adaptation of deep networks. In Proceedings of International Conference on Machine Learning, pages 1126–1135, 2017." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 437, + 545, + 480 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 437, + 545, + 480 + ], + "spans": [ + { + "bbox": [ + 308, + 437, + 545, + 480 + ], + "type": "text", + "content": "[13] Li Gu, Zhixiang Chi, Huan Liu, Yuanhao Yu, and Yang Wang. Improving protonet for few-shot video object recognition: Winner of orbit challenge 2022. arXiv preprint arXiv:2210.00174, 2022." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 482, + 545, + 535 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 482, + 545, + 535 + ], + "spans": [ + { + "bbox": [ + 308, + 482, + 545, + 535 + ], + "type": "text", + "content": "[14] Michael Gutmann and Aapo Hyvarinen. Noise-contrastive estimation: A new estimation principle for unnormalized statistical models. In Proceedings of the International Conference on Artificial Intelligence and Statistics, pages 297–304, 2010." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 537, + 545, + 591 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 537, + 545, + 591 + ], + "spans": [ + { + "bbox": [ + 308, + 537, + 545, + 591 + ], + "type": "text", + "content": "[15] Kai Han, Sylvestre-Alvise Rebuffi, Sebastien Ehrhardt, Andrea Vedaldi, and Andrew Zisserman. Automatically discovering and learning new visual categories with ranking statistics. In International Conference on Learning Representations, 2020." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 593, + 545, + 646 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 593, + 545, + 646 + ], + "spans": [ + { + "bbox": [ + 308, + 593, + 545, + 646 + ], + "type": "text", + "content": "[16] Kai Han, Sylvestre-Alvise Rebuffi, Sebastien Ehrhardt, Andrea Vedaldi, and Andrew Zisserman. Autonovel: Automatically discovering and learning novel visual categories. IEEE Transactions on Pattern Analysis and Machine Intelligence, 44(10):6767-6781, 2021." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 647, + 545, + 690 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 647, + 545, + 690 + ], + "spans": [ + { + "bbox": [ + 308, + 647, + 545, + 690 + ], + "type": "text", + "content": "[17] Kai Han, Andrea Vedaldi, and Andrew Zisserman. Learning to discover novel visual categories via deep transfer clustering. In Proceedings of the IEEE International Conference on Computer Vision, pages 8401-8409, 2019." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 692, + 545, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 692, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 308, + 692, + 545, + 714 + ], + "type": "text", + "content": "[18] Kaiming He, Haoqi Fan, Yuxin Wu, Saining Xie, and Ross Girshick. Momentum contrast for unsupervised visual rep" + } + ] + } + ], + "index": 25 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1663" + } + ] + } + ], + "index": 27 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 105 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 105 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 105 + ], + "type": "text", + "content": "resentation learning. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 9729-9738, 2020." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 106, + 287, + 149 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 106, + 287, + 149 + ], + "spans": [ + { + "bbox": [ + 48, + 106, + 287, + 149 + ], + "type": "text", + "content": "[19] Kaiming He, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. Deep residual learning for image recognition. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 770-778, 2016." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 150, + 287, + 183 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 150, + 287, + 183 + ], + "spans": [ + { + "bbox": [ + 48, + 150, + 287, + 183 + ], + "type": "text", + "content": "[20] Khurram Javed and Martha White. Meta-learning representations for continual learning. Advances in Neural Information Processing Systems, 32, 2019." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 184, + 288, + 237 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 184, + 288, + 237 + ], + "spans": [ + { + "bbox": [ + 48, + 184, + 288, + 237 + ], + "type": "text", + "content": "[21] KJ Joseph, Sujoy Paul, Gaurav Aggarwal, Soma Biswas, Piyush Rai, Kai Han, and Vineeth N Balasubramanian. Novel class discovery without forgetting. In Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 570-586, 2022." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 239, + 287, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 239, + 287, + 293 + ], + "spans": [ + { + "bbox": [ + 48, + 239, + 287, + 293 + ], + "type": "text", + "content": "[22] Prannay Khosla, Piotr Teterwak, Chen Wang, Aaron Sarna, Yonglong Tian, Phillip Isola, Aaron Maschinot, Ce Liu, and Dilip Krishnan. Supervised contrastive learning. Advances in Neural Information Processing Systems, 33:18661-18673, 2020." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 293, + 287, + 326 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 293, + 287, + 326 + ], + "spans": [ + { + "bbox": [ + 48, + 293, + 287, + 326 + ], + "type": "text", + "content": "[23] Alex Krizhevsky, Geoffrey Hinton, et al. Learning multiple layers of features from tiny images. Handbook of Systemic Autoimmune Diseases, 1(4), 2009." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 327, + 287, + 358 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 327, + 287, + 358 + ], + "spans": [ + { + "bbox": [ + 48, + 327, + 287, + 358 + ], + "type": "text", + "content": "[24] Harold W Kuhn. The hungarian method for the assignment problem. Naval Research Logistics Quarterly, 2(1-2):83-97, 1955." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 360, + 287, + 381 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 360, + 287, + 381 + ], + "spans": [ + { + "bbox": [ + 48, + 360, + 287, + 381 + ], + "type": "text", + "content": "[25] Ya Le and Xuan Yang. Tiny imagenet visual recognition challenge. CS 231N, 7(7):3, 2015." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 383, + 287, + 415 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 383, + 287, + 415 + ], + "spans": [ + { + "bbox": [ + 48, + 383, + 287, + 415 + ], + "type": "text", + "content": "[26] Zhizhong Li and Derek Hoiem. Learning without forgetting. IEEE Transactions on Pattern Analysis and Machine Intelligence, 40(12):2935-2947, 2017." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 415, + 287, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 415, + 287, + 470 + ], + "spans": [ + { + "bbox": [ + 48, + 415, + 287, + 470 + ], + "type": "text", + "content": "[27] Hanwen Liang, Niamul Quader, Zhixiang Chi, Lizhe Chen, Peng Dai, Juwei Lu, and Yang Wang. Self-supervised spatiotemporal representation learning by exploiting video continuity. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 36, pages 1564-1573, 2022." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 471, + 287, + 524 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 471, + 287, + 524 + ], + "spans": [ + { + "bbox": [ + 48, + 471, + 287, + 524 + ], + "type": "text", + "content": "[28] Huan Liu, Zhixiang Chi, Yuanhao Yu, Yang Wang, Jun Chen, and Jin Tang. Meta-auxiliary learning for future depth prediction in videos. In Proceedings of the IEEE Winter Conference on Applications of Computer Vision, pages 5756-5765, 2023." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 525, + 287, + 580 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 525, + 287, + 580 + ], + "spans": [ + { + "bbox": [ + 48, + 525, + 287, + 580 + ], + "type": "text", + "content": "[29] Huan Liu, Li Gu, Zhixiang Chi, Yang Wang, Yuanhao Yu, Jun Chen, and Jin Tang. Few-shot class-incremental learning via entropy-regularized data-free replay. In Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 146–162, 2022." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 581, + 287, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 581, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 48, + 581, + 287, + 635 + ], + "type": "text", + "content": "[30] Huan Liu, Zijun Wu, Liangyan Li, Sadaf Salehkalaibar, Jun Chen, and Keyan Wang. Towards multi-domain single image dehazing via test-time training. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 5831-5840, 2022." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 636, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 636, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 636, + 287, + 689 + ], + "type": "text", + "content": "[31] Yaoyao Liu, Yuting Su, An-An Liu, Bernt Schiele, and Qianru Sun. Mnemonics training: Multi-class incremental learning without forgetting. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 12245–12254, 2020." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 690, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 690, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 690, + 287, + 713 + ], + "type": "text", + "content": "[32] Yiwei Lu, Frank Yu, Mahesh Kumar Krishna Reddy, and Yang Wang. Few-shot scene-adaptive anomaly detection. In" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 712 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "text", + "content": "Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 125-141, 2020." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 96, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 96, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 96, + 545, + 150 + ], + "type": "text", + "content": "[33] Tian Pan, Yibing Song, Tianyu Yang, Wenhao Jiang, and Wei Liu. Videomoco: Contrastive video representation learning with temporally adversarial examples. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 11205-11214, 2021." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 152, + 545, + 185 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 185 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 185 + ], + "type": "text", + "content": "[34] Sachin Ravi and Hugo Larochelle. Optimization as a model for few-shot learning. In International Conference on Learning Representations, 2017." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 186, + 545, + 230 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 186, + 545, + 230 + ], + "spans": [ + { + "bbox": [ + 307, + 186, + 545, + 230 + ], + "type": "text", + "content": "[35] Subhankar Roy, Mingxuan Liu, Zhun Zhong, Nicu Sebe, and Elisa Ricci. Class-incremental novel class discovery. In Proceedings of the IEEE Conference on European Conference on Computer Vision, pages 317-333, 2022." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 232, + 545, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 232, + 545, + 274 + ], + "spans": [ + { + "bbox": [ + 307, + 232, + 545, + 274 + ], + "type": "text", + "content": "[36] Adam Santoro, Sergey Bartunov, Matthew Botvinick, Daan Wierstra, and Timothy Lillicrap. Meta-learning with memory-augmented neural networks. In International Conference on Machine Learning, pages 1842-1850, 2016." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 276, + 545, + 309 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 276, + 545, + 309 + ], + "spans": [ + { + "bbox": [ + 307, + 276, + 545, + 309 + ], + "type": "text", + "content": "[37] Karen Simonyan and Andrew Zisserman. Very deep convolutional networks for large-scale image recognition. In International Conference on Learning Representations, 2014." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 310, + 545, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 310, + 545, + 342 + ], + "spans": [ + { + "bbox": [ + 307, + 310, + 545, + 342 + ], + "type": "text", + "content": "[38] Jake Snell, Kevin Swersky, and Richard Zemel. Prototypical networks for few-shot learning. Advances in Neural Information Processing Systems, 30, 2017." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 344, + 545, + 388 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 344, + 545, + 388 + ], + "spans": [ + { + "bbox": [ + 307, + 344, + 545, + 388 + ], + "type": "text", + "content": "[39] Jae Woong Soh, Sunwoo Cho, and Nam Ik Cho. Meta-transfer learning for zero-shot super-resolution. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 3516-3525, 2020." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 389, + 545, + 433 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 389, + 545, + 433 + ], + "spans": [ + { + "bbox": [ + 307, + 389, + 545, + 433 + ], + "type": "text", + "content": "[40] Sagar Vaze, Kai Han, Andrea Vedaldi, and Andrew Zisserman. Generalized category discovery. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 7492-7501, 2022." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 434, + 545, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 434, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 307, + 434, + 545, + 487 + ], + "type": "text", + "content": "[41] Yue Wu, Yinpeng Chen, Lijuan Wang, Yuancheng Ye, Zicheng Liu, Yandong Guo, and Yun Fu. Large scale incremental learning. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 374-382, 2019." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 490, + 545, + 545 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 490, + 545, + 545 + ], + "spans": [ + { + "bbox": [ + 307, + 490, + 545, + 545 + ], + "type": "text", + "content": "[42] Yanan Wu, Tengfei Liang, Songhe Feng, Yi Jin, Gengyu Lyu, Haojun Fei, and Yang Wang. Metazscil: A meta-learning approach for generalized zero-shot class incremental learning. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 37, pages 10408-10416, 2023." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 546, + 545, + 600 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 546, + 545, + 600 + ], + "spans": [ + { + "bbox": [ + 307, + 546, + 545, + 600 + ], + "type": "text", + "content": "[43] Chi Zhang, Nan Song, Guosheng Lin, Yun Zheng, Pan Pan, and Yinghui Xu. Few-shot incremental learning with continually evolved classifiers. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 12455–12464, 2021." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 602, + 545, + 656 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 602, + 545, + 656 + ], + "spans": [ + { + "bbox": [ + 307, + 602, + 545, + 656 + ], + "type": "text", + "content": "[44] Marvin Zhang, Henrik Marklund, Nikita Dhawan, Abhishek Gupta, Sergey Levine, and Chelsea Finn. Adaptive risk minimization: Learning to adapt to domain shift. Advances in Neural Information Processing Systems, 34:23664-23678, 2021." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 658, + 545, + 712 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 658, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 307, + 658, + 545, + 712 + ], + "type": "text", + "content": "[45] Xinwei Zhang, Jianwen Jiang, Yutong Feng, Zhi-Fan Wu, Xibin Zhao, Hai Wan, Mingqian Tang, Rong Jin, and Yue Gao. Grow and merge: A unified framework for continuous categories discovery. Advances in Neural Information Processing Systems, 2022." + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 748, + 315, + 757 + ], + "type": "text", + "content": "1664" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 173 + ], + "type": "list", + "angle": 0, + "index": 2, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 116 + ], + "type": "text", + "content": "[46] Tao Zhong, Zhixiang Chi, Li Gu, Yang Wang, Yuanhao Yu, and Jin Tang. Meta-dmoe: Adapting to domain shift by metadata distillation from mixture-of-experts. Advances in Neural Information Processing Systems, 35:22243-22257, 2022." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 118, + 286, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 118, + 286, + 173 + ], + "spans": [ + { + "bbox": [ + 48, + 118, + 286, + 173 + ], + "type": "text", + "content": "[47] Zhun Zhong, Enrico Fini, Subhankar Roy, Zhiming Luo, Elisa Ricci, and Nicu Sebe. Neighborhood contrastive learning for novel class discovery. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 10867-10875, 2021." + } + ] + } + ], + "index": 1 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 296, + 749, + 315, + 757 + ], + "type": "text", + "content": "1665" + } + ] + } + ], + "index": 3 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/6cc2d292-7284-48d5-98ac-76d175845d01_content_list.json b/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/6cc2d292-7284-48d5-98ac-76d175845d01_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..05620f02f7013d41cf9a2f0c5a694a686ab2e2a9 --- /dev/null +++ b/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/6cc2d292-7284-48d5-98ac-76d175845d01_content_list.json @@ -0,0 +1,1437 @@ +[ + { + "type": "text", + "text": "Metric3D: Towards Zero-shot Metric 3D Prediction from A Single Image", + "text_level": 1, + "bbox": [ + 148, + 161, + 821, + 183 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Wei Yin $^{1*}$ , Chi Zhang $^{2*}$ , Hao Chen $^{3\\dagger}$ , Zhipeng Cai $^{4}$ , Gang Yu $^{2}$ , Kaixuan Wang $^{1}$ , Xiaozhi Chen $^{1}$ , Chunhua Shen $^{3}$", + "bbox": [ + 179, + 205, + 792, + 239 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{1}$ DJI Technology $^{2}$ Tencent $^{3}$ Zhejiang University $^{4}$ Intel Labs", + "bbox": [ + 220, + 243, + 751, + 261 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "e-mail: $^1\\mathrm{yvanwy}$ @outlook.com,{halfbullet.wang,xiaozhi.chen} $@$ dji.com;", + "bbox": [ + 192, + 261, + 777, + 277 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "$^{2}$ johnczhang, skicyyu@tencent.com;", + "bbox": [ + 333, + 277, + 640, + 292 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "3haochen.cad@zju.edu.cn, chunhua@me.com; 4zhipeng.cai@intel.com", + "bbox": [ + 212, + 292, + 759, + 309 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/5fbb8b4b87a3aa86be43fc5fc38f8cee19fbac282b9f9338c9ba593883b20ae5.jpg", + "image_caption": [ + "Figure 1 - Illustration and applications of our metric 3D reconstruction method. Top (metrology): we use two phones (iPhone 12 and an Android phone) to capture the scene and measure the size of tables. With the photos' metadata, we perform 3D metric reconstruction and then measure tables' sizes (marked in red), which are very close to the ground truth (marked in blue). In contrast, the recent method LeReS [57] performs much worse and is unable to predict metric 3D by design. Bottom (dense SLAM mapping): existing SOTA mono-SLAM methods usually face scale drift problems (see the red arrows) in large-scale scenes and are unable to achieve the metric scale, while, naively inputting our metric depth, Droid-SLAM [44] can recover much more accurate trajectory and perform the metric dense mapping (see the red measurements). Note that all testing data are unseen to our model." + ], + "image_footnote": [], + "bbox": [ + 151, + 340, + 821, + 638 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 256, + 727, + 328, + 742 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Reconstructing accurate 3D scenes from images is a long-standing vision task. Due to the ill-posedness of the single-image reconstruction problem, most well-established methods are built upon multi-view geometry. State-of-the-art (SOTA) monocular metric depth estimation meth", + "bbox": [ + 112, + 758, + 472, + 828 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "ods can only handle a single camera model and are unable to perform mixed-data training due to metric ambiguity. Meanwhile, SOTA monocular methods trained on large mixed datasets achieve zero-shot generalization by learning affine-invariant depths, which cannot recover real-world metrics. In this work, we show that the key to a zero-shot single-view metric depth model lies in the combination of large-scale data training and resolving the metric ambiguity from various camera models. We propose a", + "bbox": [ + 500, + 729, + 859, + 854 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 138, + 45, + 207, + 80 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation.", + "bbox": [ + 259, + 42, + 781, + 56 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "Except for this watermark, it is identical to the accepted version;", + "bbox": [ + 336, + 56, + 702, + 70 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 308, + 70, + 732, + 84 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Equal contributions.", + "bbox": [ + 130, + 843, + 235, + 854 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "†Corresponding author.", + "bbox": [ + 132, + 854, + 245, + 866 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "9043", + "bbox": [ + 483, + 888, + 513, + 900 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "canonical camera space transformation module, which explicitly addresses the ambiguity problems and can be effortlessly plugged into existing monocular models. Equipped with our module, monocular models can be stably trained over 8 millions of images with thousands of camera models, resulting in zero-shot generalization to in-the-wild images with unseen camera settings. Experiments demonstrate SOTA performance of our method on 7 zero-shot benchmarks. Notably, our method won the championship in the 2nd Monocular Depth Estimation Challenge. Our method enables the accurate recovery of metric 3D structures on randomly collected internet images, paving the way for plausible single-image metrology. The potential benefits extend to downstream tasks, which can be significantly improved by simply plugging in our model. For example, our model relieves the scale drift issues of monocular-SLAM (Fig. 1), leading to high-quality metric scale dense mapping. The code is available at https://github.com/YvanYin/Metric3D.", + "bbox": [ + 109, + 126, + 473, + 388 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 114, + 415, + 235, + 429 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "3D reconstruction from images is the core of many computer vision applications, such as autonomous driving and robotics. Main-stream methods leverage multi-view geometry [15] to confidently recover 3D structures. However, these methods cannot be applied to a single image, making 3D reconstruction hard without a prior. State-of-the-art transferable methods, such as MiDaS [32], LeReS [57], and HDN [60], learn such a prior from a large dataset, but they can only output affine-invariant depths, i.e., which are accurate only up to an unknown offset and scale. Though monocular metric depth estimation methods [59, 2] work on a single dataset with a single camera model, they cannot generalize to unseen cameras or scenes. This work aims to address the above problems by learning a zero-shot, single view, metric depth model.", + "bbox": [ + 109, + 438, + 473, + 645 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "According to the predicted depth, existing methods are categorized into learning metric depth [59, 53, 2, 52], learning relative depth [48, 49, 6, 5], and learning affine-invariant depth [57, 56, 32, 31, 60]. Although the metric depth methods [59, 53, 55, 2, 52] have achieved impressive accuracy on various benchmarks, they must train and test on the dataset with the same camera intrinsics. Therefore, training datasets of metric depth methods are often small, as it is hard to collect a large dataset covering diverse scenes using one identical camera. The consequence is that all these models are not transferable - they generalize poorly to images in the wild, not to mention the camera parameters of test images can vary too. A compromise is to learn the relative depth [6, 48], which only represents the depth ordering information. Thus the application is very limited. Learning affine-invariant depth finds a trade-off between the above", + "bbox": [ + 109, + 646, + 473, + 867 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "two categories of methods. With large-scale data, they decouple the metric information during training and achieve impressive robustness and generalization ability. The recent SOTA LeReS [57] can recover 3D scenes in the wild, but only up to an unknown scale and shift.", + "bbox": [ + 496, + 126, + 859, + 195 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "This work focuses on learning a zero-shot transferable model to recover metric 3D from a single image. First, we analyze the metric ambiguity issues in monocular depth estimation and study different camera parameters in depth, including the pixel size, focal length, and sensor size. We observe that the focal length is the critical factor for accurate metric recovery. By design, LeReS [57] does not take the focal length information into account during training. As shown in Sec. 3.1, only from the image appearance, various focal lengths may cause metric ambiguity, thus they decouple the depth scale in training. To solve the problem of varying focal lengths, CamConv [11] encodes the camera model in the network, which enforces the network to implicitly understand camera models from the image appearance and then bridges the imaging size to the real-world size. However, training data contains limited images and types of cameras, which challenges data diversity and network capacity. In contrast, we propose a canonical camera transformation method in training. It is inspired by the human body reconstruction methods. To improve reconstructed shape quality on countless poses, they map all samples to a canonical pose space [29] to reduce pose variance. Similarly, we transform all training data to a canonical camera space where the processed images are coarsely regarded as captured by the same camera. To achieve such transformation, we propose two different methods. The first one tries to adjust the image appearance to simulate the canonical camera, while the other one transforms the ground-truth labels for supervision. Camera models are not encoded in the network, making our method easily applicable to existing architectures. During inference, a de-canonical transformation is employed to recover metric information. To further boost the depth accuracy, we propose a random proposal normalization loss. It is inspired by the scale-shift invariant loss [57, 32, 60], which decouples the depth scale to emphasize the single image's distribution. However, they perform on the whole image, which inevitably squeezes the fine-grained depth difference. We propose to randomly crop several patches from images and enforce the scale-shift invariant loss [57, 32] on them. Our loss emphasizes the local geometry and distribution of the single image.", + "bbox": [ + 496, + 198, + 859, + 767 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "With the proposed method, we can easily scale up model training to 8 million images from 11 datasets of diverse scene types (indoor and outdoor) and camera models (tens of thousands of different cameras), leading to zero-shot transferability and a significantly improved accuracy. Our model can accurately reconstruct metric 3D from randomly collected Internet images, enabling plausible single-image", + "bbox": [ + 496, + 768, + 861, + 868 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "9044", + "bbox": [ + 483, + 888, + 514, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "metrology. Different from affine-invariant depth models, our model can also directly improve various downstream tasks. As an example (Fig. 1), with the predicted metric depths from our model, we can significantly reduce the scale drift of monocular SLAM [44, 43] systems, achieving much better mapping quality with real-world metric recovery. Our model also enables large-scale 3D reconstruction [17]. The model achieves the championship in the 2nd Monocular Depth Estimation Challenge [42]. To summarize, our main contributions are:", + "bbox": [ + 111, + 126, + 473, + 263 + ], + "page_idx": 2 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose a canonical and de-canonical camera transformation method to solve the metric depth ambiguity problems from various cameras setting. It enables the learning of strong zero-shot monocular metric depth models from large-scale datasets.", + "- We propose a random proposal normalization loss to boost the depth accuracy effectively;", + "- Our model achieves state-of-the-art performance on 7 zero-shot benchmarks. It can perform high-quality 3D metric structure recovery in the wild and benefit several downstream tasks, such as mono-SLAM [44, 27], 3D scene reconstruction [17], and metrology [62]." + ], + "bbox": [ + 129, + 273, + 473, + 444 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 112, + 455, + 243, + 469 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3D reconstruction from a single image. Reconstructing various objects from a single image has been well studied [1, 46, 47]. They can produce high-quality 3D models of cars, planes, tables, and human body [33, 34]. The main challenge is how to best recover objects' details, how to represent them with limited memory, and how to generalize to more diverse objects. However, all these methods rely on learning priors specific to a certain object class or instance, typically from 3D supervision, and can therefore not work for full scene reconstruction. Apart from these reconstructing objects works, several works focus on scene reconstruction [51] from a single image. Saxena et al. [35] construct the scene based on the assumption that the whole scene can be segmented into several small planes. With planes' orientation and location, the 3D structure can be represented. Recently, LeReS [57] propose to use a strong monocular depth estimation model to do scene reconstruction. However, they can only recover the shape up to a scale. Zhang et al. [61] recently propose a zero-shot geometry-preserving depth estimation model that is capable of making depth predictions up to an unknown scale, without requiring scale-invariant depth annotations for training. In contrast to these works, our method can recover the metric 3D structure.", + "bbox": [ + 111, + 479, + 473, + 796 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Supervised monocular depth estimation. After several benchmarks [39, 12] are established, neural network based methods [59, 55, 2, 25] have dominated since then. Several approaches regress the continuous depth from the aggregation of information in an image [10]. As depth distribution", + "bbox": [ + 111, + 797, + 473, + 867 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "corresponding to different RGBs can vary to a large extent, some methods [55, 2] discretize the depth and formulate this problem to a classification [53], which often achieves better performance. The generalization issue of deep models for 3D metric recovery is related to two problems. The first one is to generalize to diverse scenes, while the other one is how to predict accurate metric information under various camera settings. The first problem has been well addressed by recent methods. Some works [49, 48, 53] propose to construct a large-scale relative depth dataset, such as DIW [5] and OASIS [6], and then they target learning the relative relations. However, the relative depth loses geometric structure information. To improve the recovered geometry quality, learning affine-invariant depth methods, such as MiDaS [32], LeReS [57], and HDN [60] are proposed. By mixing large-scale data, state-of-the-art performance and the generalization over scenes are improved continuously. Note that by design, these methods are unable to recover the metric information. How to achieve both strong generalization and accurate metric information over diverse scenes is the key problem that we attempt to tackle.", + "bbox": [ + 496, + 126, + 859, + 416 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Large-scale data training. Recently, various natural language problems and computer vision problems [54, 30, 22] have achieved impressive progress with large-scale data training. CLIP [30] is a promising classification model, which is trained on billions of paired image and language descriptions data. It achieved state-of-the-art performance over several classification benchmarks by zero-shot testing. For depth prediction, large-scale data training has been widely applied. Ranft et al. [32] mixed over 2 million data in training, LeReS [56] collected over 300 thousand data, Eftekhar et al. [9] also merged millions of data to build a strong depth prediction model.", + "bbox": [ + 496, + 417, + 859, + 583 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Method", + "text_level": 1, + "bbox": [ + 500, + 598, + 584, + 614 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Preliminaries. We consider the pin-hole camera model with intrinsic parameters: $[[\\hat{f} /\\delta ,0,u_0],[0,\\hat{f} /\\delta ,v_0],[0,0,1]]$ where $\\hat{f}$ is the focal length (in micrometers), $\\delta$ is the pixel size (in micrometers), and $(u_0,v_0)$ is the principle center. $f = \\hat{f} /\\delta$ is the pixel-represented focal length used in vision algorithms.", + "bbox": [ + 496, + 623, + 859, + 708 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Metric Ambiguity Analysis", + "text_level": 1, + "bbox": [ + 500, + 719, + 723, + 734 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Fig. 3 presents an example of photos taken by different cameras and at different distances. Only from the image's appearance, one may think the last two photos are taken at a similar location by the same camera. In fact, due to different focal lengths, these are captured at different locations. Thus, camera intrinsic parameters are critically important for the metric estimation from a single image, as otherwise, the problem is ill posed. To avoid such metric ambiguity, recent methods, such as MiDaS [32] and LeReS [57],", + "bbox": [ + 496, + 742, + 859, + 867 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "9045", + "bbox": [ + 483, + 888, + 514, + 900 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/7728a49709e41201261ada1ad4e63fa21cf7c8d4cf6c70b176d2fab65b966be8.jpg", + "image_caption": [ + "Figure 2 - Pipeline. Given an input image $I$ , we first transform it to the canonical space using CSTM. The transformed image $I_{c}$ is fed into a depth estimation model to produce the metric depth $D_{c}$ in the canonical space. During training, $D_{c}$ is supervised by a GT depth $D_{c}^{*}$ which is also transformed into the canonical space. In inference, after producing the metric depth $D_{c}$ in the canonical space, we perform a de-canonical transformation to convert it back to the space of the original input $I$ . The canonical and de-canonical transformations are executed using camera intrinsics." + ], + "image_footnote": [], + "bbox": [ + 148, + 125, + 818, + 243 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/f5d089fa78130278337e20475ace3f4ba63612965458690c503c830081e447c7.jpg", + "image_caption": [ + "focal=26mm,depth=2m" + ], + "image_footnote": [], + "bbox": [ + 116, + 299, + 232, + 393 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/6e59db16f5bd876046238ea2174fc990347698e9ecc7020f5bf1573445e41404.jpg", + "image_caption": [ + "focal=52mm,depth=2m" + ], + "image_footnote": [], + "bbox": [ + 233, + 299, + 348, + 393 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/71e22d2db032afff640b57fb43959242720d3a29b19ee73703aa642713f2dda8.jpg", + "image_caption": [ + "focal=26mm,depth=1m", + "Figure 3 - Photos of a chair captured at different distances with different cameras. The first two photos are captured at the same distance but with different cameras, while the last one is taken at a closer distance with the same camera as the first one." + ], + "image_footnote": [], + "bbox": [ + 348, + 299, + 465, + 393 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "decouple the metric from the supervision and compromise learning the affine-invariant depth.", + "bbox": [ + 112, + 457, + 470, + 484 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Fig. 4 (A) shows a simple pin-hole perspective projection. Object $A$ locating at $d_{a}$ is projected to $A^{\\prime}$ . Based on the principle of similarity, we have the equation:", + "bbox": [ + 112, + 484, + 470, + 526 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nd _ {a} = \\hat {S} \\left[ \\frac {\\hat {f}}{\\hat {S} ^ {\\prime}} \\right] = \\hat {S} \\cdot \\alpha \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 225, + 534, + 470, + 564 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\hat{S}$ and $\\hat{S}^{\\prime}$ are the real and imaging size respectively. $\\hat{\\tau}$ denotes variables are in the physical metric (e.g., millimeter). To recover $d_{a}$ , focal length, imaging size of the object, and real-world object size must be available. Estimating the focal length from a single image is a challenging and ill-posed problem. Although several methods [57, 16] have been explored, the accuracy is still far from being satisfactory. Here, we simplify the problem by assuming the focal length of a training/test image is available. Understanding the imaging size is much easier for a neural network. To obtain the real-world object size, a neural network needs to understand the semantic scene layout and the object, at which a neural network excels. We define $\\alpha = \\hat{f} / \\hat{s}^{\\prime}$ , so $d_{a}$ is proportional to $\\alpha$ .", + "bbox": [ + 111, + 561, + 470, + 755 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We make the following observations regarding sensor size, pixel size, and focal length.", + "bbox": [ + 112, + 756, + 472, + 782 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "O1: Sensor size and pixel size do not affect the metric depth estimation. Based on the perspective projection (Fig. 4 (A)), the sensor size only affects the field of view (FOV) and is irrelevant to $\\alpha$ , thus does not affect the metric depth estimation. For the pixel size, we assume two cameras with different pixel sizes ( $\\delta_{1} = 2\\delta_{2}$ ) but the same focal", + "bbox": [ + 112, + 784, + 472, + 866 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "length $\\hat{f}$ to capture the same object locating at $d_{a}$ . Fig. 4 (B) shows their captured photos. According to the preliminaries, the pixel-represented focal length $f_{1} = \\frac{1}{2} f_{2}$ . As the second camera has a smaller pixel size, although in the same projected imaging size $\\hat{S}'$ , the pixel-represented image resolution is $S_1' = \\frac{1}{2} S_2'$ . According to Eq. (1), $\\frac{\\hat{f}}{\\delta_1 \\cdot S_1'} = \\frac{\\hat{f}}{\\delta_2 \\cdot S_2'}$ , i.e. $\\alpha_{1} = \\alpha_{2}$ , so $d_{1} = d_{2}$ . Therefore, different camera sensors would not affect the metric depth estimation.", + "bbox": [ + 496, + 300, + 857, + 416 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "O2: The focal length is vital for metric depth estimation. Fig. 3 shows the metric ambiguity issue caused by the unknown focal length. In Fig. 5, two cameras $(\\hat{f}_1 = 2\\hat{f}_2)$ are at distances $d_{1}$ and $d_{2}$ , the imaging sizes on cameras are the same. Only from the appearance, the network will be confused when supervised with different labels. Based on this, we propose a canonical camera transformation method to solve the supervision and image appearance conflicts.", + "bbox": [ + 496, + 417, + 857, + 527 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Canonical Camera Transformation", + "text_level": 1, + "bbox": [ + 500, + 537, + 779, + 551 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The core idea is to set up a canonical camera space $((f_x^c, f_y^c), f_x^c = f_y^c = f^c$ in experiments) and transform all training data to this space. Consequently, all data can roughly be regarded as captured by the canonical camera. We propose two transformation methods, i.e. either on the input image $(\\mathbf{I} \\in \\mathbb{R}^{H \\times W \\times 3})$ or the GT label $(\\mathbf{D} \\in \\mathbb{R}^{H \\times W})$ .", + "bbox": [ + 498, + 560, + 857, + 642 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/ae32257d9e147b759fbfdcb3d01909c276e77aa6107e29be49a9cc992a4135e5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 511, + 642, + 658, + 715 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/213abb90bd8d03fb56bbbd45bc9fd6ee300fff5c4a8d2efd313822101c308d31.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 658, + 642, + 846, + 715 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/fee3c55f6187142e4df0d5adffd27dc7939de79dd4b583d1693e55caf2483918.jpg", + "image_caption": [ + "Figure 4 - Pinhole camera model. (A) Object $A$ at the distance $d_{a}$ is projected to the image plane. (B) Using two cameras to capture the car. The left one has a larger pixel size. Although the projected imaging sizes are the same, the pixel-represented images (resolution) are different.", + "Figure 5 - Illustration of two cameras with different focal length at different distance. As $f_{1} = 2f_{2}$ and $d_{1} = 2d_{2}$ , $A$ is projected to two image planes with the same imaging size (i.e. $A_{1}' = A_{2}'$ )." + ], + "image_footnote": [], + "bbox": [ + 509, + 777, + 849, + 840 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "9046", + "bbox": [ + 483, + 888, + 513, + 898 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The original intrinsics are $\\{f, u_0, v_0\\}$ .", + "bbox": [ + 112, + 125, + 344, + 138 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Method1: transforming depth labels (CSTM_label). Fig. 3's ambiguity is for depths. Thus our first method directly transforms the ground-truth depth labels to solve this problem. Specifically, we scale the ground-truth depth $(\\mathbf{D}^{*})$ with the ratio $\\omega_{d} = \\frac{f^{c}}{f}$ in training, i.e., $\\mathbf{D}_c^* = \\omega_d\\mathbf{D}^*$ . The original camera model is transformed to $\\{f^c,u_0,v_0\\}$ . In inference, the predicted depth $(\\mathbf{D}_c)$ is in the canonical space and needs to perform a de-canonical transformation to recover the metric information, i.e., $\\mathbf{D} = \\frac{1}{\\omega_d}\\mathbf{D}_c$ . Note the input $\\mathbf{I}$ does not perform any transformation, i.e., $\\mathbf{I}_c = \\mathbf{I}$ .", + "bbox": [ + 111, + 140, + 472, + 280 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Method2: transforming input images (CSTM_image). From another view, the ambiguity is caused by the similar image appearance. Thus this method is to transform the input image to simulate the canonical camera imaging effect. Specifically, the image $\\mathbf{I}$ is resized with the ratio $\\omega_{r} = \\frac{f^{c}}{f}$ , i.e., $\\mathbf{I}_c = \\mathfrak{T}(\\mathbf{I},\\omega_r)$ , where $\\mathfrak{T}(\\cdot)$ denotes image resize. The optical center is resized, thus the canonical camera model is $\\{f^c,\\omega_ru_0,\\omega_rv_0\\}$ . The ground-truth labels are resized without any scaling, i.e., $\\mathbf{D}_c^* = \\mathfrak{T}(\\mathbf{D}^*,\\omega_r)$ . In inference, the de-canonical transformation is to resize the prediction to the original size without scaling, i.e., $\\mathbf{D} = \\mathfrak{T}(\\mathbf{D}_c,\\frac{1}{\\omega_r})$", + "bbox": [ + 111, + 281, + 472, + 435 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Fig. 2 shows the pipeline. After performing either transformation, we randomly crop a patch for training. The cropping only adjusts the FOV and the optical center, thus not causing any metric ambiguity issues. In the labels transformation method $\\omega_{r} = 1$ and $\\omega_{d} = \\frac{f^{c}}{f}$ , while $\\omega_{d} = 1$ and $\\omega_{r} = \\frac{f^{c}}{f}$ in the images transformation method. The training objective is as follows:", + "bbox": [ + 111, + 436, + 472, + 536 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\min _ {\\theta} \\left| \\mathfrak {N} _ {d} \\left(\\mathbf {I} _ {c}, \\theta\\right) - \\mathbf {D} _ {c} ^ {*} \\right| \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 223, + 549, + 470, + 569 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\theta$ is the network's $(\\mathcal{N}_d(\\cdot))$ parameters, $\\mathbf{D}_c^*$ and $\\mathbf{I}_c$ are transformed ground-truth depth labels and images.", + "bbox": [ + 111, + 575, + 472, + 603 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Supervision. To further boost the performance, we propose a random proposal normalization loss (RPNL). The scale-shift invariant loss [32, 57] is widely applied for the affine-invariant depth estimation, which decouples the depth scale to emphasize the single image distribution. However, such normalization based on the whole image inevitably squeezes the fine-grained depth difference, particularly in close regions. Inspired by this, we propose to randomly crop several patches $(p_{i(i = 0,\\dots,M)}\\in \\mathbb{R}^{h_i\\times w_i})$ from the ground truth $\\mathbf{D}_c^*$ and the predicted depth $\\mathbf{D}_c$ . Then we employ the median absolute deviation normalization [40] for paired patches. By normalizing the local statistics, we can enhance local contrast. The loss function is as follows:", + "bbox": [ + 111, + 604, + 472, + 784 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} L _ {\\mathrm {R P N L}} = \\frac {1}{M N} \\sum_ {p _ {i}} ^ {M} \\sum_ {j} ^ {N} \\left| \\frac {d _ {p _ {i} , j} ^ {*} - \\mu \\left(d _ {p _ {i} , j} ^ {*}\\right)}{\\frac {1}{N} \\sum_ {j} ^ {N} \\left| d _ {p _ {i} , j} ^ {*} - \\mu \\left(d _ {p _ {i} , j} ^ {*}\\right) \\right|} - \\right. \\\\ \\frac {d _ {p _ {i , j}} - \\mu \\left(d _ {p _ {i , j}}\\right)}{\\frac {1}{N} \\sum_ {j} ^ {N} \\left| d _ {p _ {i , j}} - \\mu \\left(d _ {p _ {i , j}}\\right) \\right|} \\tag {3} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 116, + 794, + 470, + 869 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $d^{*}\\in \\mathbf{D}_{c}^{*}$ and $d\\in \\mathbf{D}_c$ are the ground truth and predicted depth respectively. $\\mu (\\cdot)$ and is the median of depth. $M$ is the number of proposal crops, which is set to 32. During training, proposals are randomly cropped from the image by 0.125 to 0.5 of the original size. Furthermore, several other losses are employed, including the scale-invariant logarithmic loss [10] $L_{silog}$ , pair-wise normal regression loss [57] $L_{\\mathrm{PWN}}$ , virtual normal loss [53] $L_{\\mathrm{VNL}}$ . Note $L_{silog}$ is a variant of L1 loss. The overall losses are as follows.", + "bbox": [ + 500, + 125, + 859, + 250 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nL = L _ {\\mathrm {P W N}} + L _ {\\mathrm {V N L}} + L _ {\\text {s i l o g}} + L _ {\\mathrm {R P N L}}.\n$$\n", + "text_format": "latex", + "bbox": [ + 539, + 261, + 787, + 277 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 500, + 290, + 620, + 306 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Dataset details. We collect 11 public RGB-D datasets, and over 8 million data for training. It spreads over diverse indoor and outdoor scenes. Note that all datasets have provided camera intrinsic parameters. Over 10K different cameras are included. Furthermore, we collect 7 unseen datasets for robustness and generalization evaluation. Details of employed data are reported in the supplementary materials.", + "bbox": [ + 498, + 313, + 857, + 410 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Implementation details. We use an UNet architecture with the ConvNext-large [26] backbone. ImageNet-22K pretrained weights are used for initialization. We use AdamW with a batch size of 192, an initial learning rate 0.0001 for all layers, and the polynomial decaying method with the power of 0.9. We use 48 A100 GPUs and train for 500K iterations. Following [53], we balance all datasets in a mini-batch to ensure each dataset accounts for an almost equal ratio. In training, images are processed by the LSTM, flipped horizontally with a $50\\%$ chance, and then randomly cropped into $512 \\times 960$ . In ablation studies, training settings are different as we sample 5000 images from each dataset for training and train on 8 GPUs for 150K iterations.", + "bbox": [ + 498, + 410, + 859, + 589 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Evaluation details. a) To show the robustness of our metric depth estimation method, we test on 8 zero-shot benchmarks, including NYUv2 [39], KITTI [12], NuScenes [4], 7-scenes [38], iBIMS-1 [19], DIODE [45], ETH3D [37]. Absolute relative error (AbsRel), the accuracy under threshold $(\\delta_i < 1.25^i, i = 1,2,3)$ , root mean squared error (RMS), root mean squared error in log space (RMS_log), and log10 error (log10) metrics are employed. b) Furthermore, we also follow current affine-invariant depth benchmarks [57, 60] (Tab. 4) to evaluate the generalization ability on 5 zero-shot datasets, i.e., NYUv2, DIODE, ETH3D, ScanNet [7], and KITTI. We mainly compare with large-scale data trained models. Note that in this benchmark we follow existing methods to apply the scale shift alignment before evaluation. c) To evaluate our metric 3D reconstruction quality, we randomly sample 9 unseen scenes from NYUv2 and use colmap [36] to obtain the camera poses for multi-frame reconstruction. Chamfer $l_{1}$ distance and the F-score [18] are used to evaluate the reconstruction accuracy. d) In dense-SLAM experiments, following Li et al. [24], we", + "bbox": [ + 498, + 590, + 859, + 867 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "9047", + "bbox": [ + 483, + 888, + 513, + 898 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/2c0b3a6538b795893f82901077e11d2364e5fa61f1101d03e5475df7c882d83d.jpg", + "table_caption": [ + "Table 1 - Quantitative comparison on NYUv2 and KITTI benchmarks. Both datasets are unseen to our model, but we can achieve comparable performance with state-of-the-art methods." + ], + "table_footnote": [], + "table_body": "
NYUv2 Benchmark
Methodδ1↑δ2↑δ3↑AbsRel↓log10↓RMS↓
Li et al. [23]0.7880.9580.9910.1430.0630.635
Laina et al. [21]0.8110.9530.9880.1270.0550.573
VNL [55]0.8750.9760.9940.1080.0480.416
TrDepth [52]0.9000.9830.9960.1060.0450.365
Adabins [2]0.9030.9840.9970.1030.0440.364
NeWCRFs [59]0.9220.9920.9980.0950.0410.334
Ours LSTM_image0.9250.9830.9940.0920.0400.341
Ours LSTM_label0.9440.9860.9950.0830.0350.310
KITTI Benchmark
Methodδ1↑δ2↑δ3↑AbsRel↓RMS↓RMS_log↓
Guo et al. [14]0.9020.9690.9860.0903.2580.168
VNL [55]0.9380.9900.9980.0723.2580.117
TrDepth [52]0.9560.9940.9990.0642.7550.098
Adabins [2]0.9640.9950.9990.0582.3600.088
NeWCRFs [59]0.9740.9970.9990.0522.1290.079
Ours LSTM_image0.9670.9950.9990.0602.8430.087
Ours LSTM_label0.9640.9930.9980.0582.7700.092
", + "bbox": [ + 117, + 157, + 473, + 343 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "test on the KITTI odometry benchmark [12] and evaluate the average translational RMS drift $(\\% ,t_{rel})$ and rotational RMS drift $(^{\\circ} / 100m,r_{rel})$ errors [12].", + "bbox": [ + 112, + 358, + 472, + 401 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Zero-shot Generalization Test", + "text_level": 1, + "bbox": [ + 112, + 426, + 354, + 439 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Evaluation on metric depth benchmarks. To evaluate the accuracy of predicted metric depth, firstly, we compare with state-of-the-art (SOTA) metric depth prediction methods on NYUv2 [39], KITTI [13]. We use the same model to do all evaluations. Results are reported in Tab. 1. Without any fine-tuning or metric adjustment, we can achieve comparable performance with SOTA methods, which are trained on benchmarks for hundreds of epochs.", + "bbox": [ + 111, + 453, + 472, + 565 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Furthermore, we collect 6 unseen datasets to do more metric accuracy evaluation. These datasets contain a wide range of indoor and outdoor scenes. The camera models are also various, e.g. 7scenes has a short focal length (around 500), while ETH3D is 2000. We compare with the SOTA metric depth estimation methods and take their NYUv2 and KITTI models for indoor and outdoor scenes evaluation respectively. In Tab. 3, although 7Scenes is similar to NYUv2 and NuScenes is similar to KITTI, existing methods face a noticeable performance decrease. In contrast, our model is more robust.", + "bbox": [ + 111, + 570, + 470, + 720 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Generalization over diverse scenes. Affine-invariant depth benchmarks decouple the scale's effect, which aims to evaluate the model's generalization ability to diverse scenes. Recent impact works, such as MiDaS, LeReS, and DPT, achieved promising performance on them. Following them, we test on 5 datasets and manually align the scale and shift to the ground-truth depth before evaluation. Results are reported in Tab. 4. Although our method enforces the network to recover more challenging metric information, our method outperforms them by a large margin on most datasets.", + "bbox": [ + 111, + 728, + 472, + 866 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Applications Based on Our Method", + "text_level": 1, + "bbox": [ + 500, + 125, + 781, + 138 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "3D scene reconstruction. To demonstrate our work can recover the 3D metric shape in the wild, we first do the quantitative comparison on 9 NYUv2 scenes, which are unseen during training. We predict the per-frame metric depth and then fuse them together with provided camera poses. Results are reported in Tab. 2. We compare with the video consistent depth prediction method (RCVD [20]), the unsupervised video depth estimation method (SC-DepthV2 [3]), the 3D scene shape recovery method (LeReS [57]), affine-invariant depth estimation method (DPT [31]), and the multi-view stereo reconstruction method (DPSNet [17]). Apart from DPSNet and our method, other methods have to align the scale with the ground truth depth for each frame. Although our method does not aim for the video or multi-view reconstruction problem, our method can achieve promising consistency between frames and reconstruct much more accurate 3D scenes than others on these zero-shot scenes. From the qualitative comparison in Fig. 6, our reconstructions have much less noise and outliers.", + "bbox": [ + 496, + 146, + 859, + 409 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Dense-SLAM mapping. Monocular SLAM is an important robotics application. It takes a monocular video input to create the trajectory and dense 3D mapping. Owing to limited photometric and geometric constraints, existing methods face serious scale drift problems in large scenes and cannot recover the metric information. Our robust metric depth estimation method is a strong depth prior to the SLAM system. To demonstrate this benefit, we naively input our metric depth to the SOTA SLAM system, Droid-SLAM [44], and evaluate the trajectory on KITTI. We do not do any tuning on the original system. Trajectory comparisons are reported in Tab. 5. As Droid-SLAM can access accurate per-frame metric depth, like an RGB-D SLAM, the translation drift $(t_{rel})$ decreases significantly. Furthermore, with our depths, Droid-SLAM can perform denser and more accurate 3D mapping. An example is shown in Fig. 1 and more cases are shown in the supplementary materials.", + "bbox": [ + 496, + 409, + 859, + 643 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Metrology in the wild. To show the robustness and accuracy of our recovered metric 3D, we download Flickr photos captured by various cameras and collect coarse camera intrinsic parameters from their metadata. We use our CSTM_image model to reconstruct their metric shape and measure structures' sizes (marked in red in Fig. 7), while the ground-truth sizes are in blue. It shows that our measured sizes are very close to the ground-truth sizes.", + "bbox": [ + 496, + 643, + 859, + 755 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.3. Ablation Study", + "text_level": 1, + "bbox": [ + 500, + 762, + 638, + 777 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Ablation on canonical transformation. We study the effect of our proposed canonical transformation for the input images ('CSTM_input') and the canonical transformation for the ground-truth labels ('CSTM_output'). Results are reported in Tab. 6. We train the model on sampled mixed data (55K images) and test it on 6 datasets. A naive base", + "bbox": [ + 496, + 782, + 859, + 867 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "9048", + "bbox": [ + 483, + 888, + 513, + 898 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/2fe9f6e8cc56acebb0e3a9ef6f523345e741c258658d349adba40a4e976890f8.jpg", + "table_caption": [ + "Table 2 - Quantitative comparison of 3D scene reconstruction with LeReS [57], DPT [31], RCVD [20], SC-DepthV2 [3], and a learning-based MVS method (DPSNet [17]) on 9 unseen NYUv2 scenes. Apart from DPSNet and ours, other methods have to align the scale with ground truth depth for each frame. As a result, our reconstructed 3D scenes achieve the best performance." + ], + "table_footnote": [], + "table_body": "
MethodBasement_0001aBedroom_0015Dining_room_0004Kitchen_0008Classroom_0004Playroom_0002Office_0024Office_0004Dining_room_0033
C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑
RCVD [20]0.3640.2760.0740.5820.4620.2510.0530.6200.1870.3270.7910.1870.3240.2410.6460.2170.4450.253
SC-DepthV2 [3]0.2540.2750.0640.5470.7490.2290.0490.6240.1670.2670.4260.2630.4820.1380.5160.2440.3560.247
DPSNet [17]0.2430.2990.1950.2760.9950.1860.2690.2030.2960.1950.1410.4850.1990.3620.2100.4620.2220.493
DPT [57]0.6980.2510.2890.2260.3960.3640.1260.3880.7800.1930.6050.2690.4540.2450.3640.2790.7510.185
LeReS [57]0.0810.5550.0640.6160.2780.4270.1470.2890.1430.4800.1450.5030.4080.1760.0960.4970.2410.325
Ours0.0420.7360.0590.6100.1590.4850.0500.6450.1450.4450.0360.8140.0690.6380.0450.7000.0600.663
", + "bbox": [ + 119, + 157, + 849, + 250 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/4b56032377236421e63e29a801ac64b51cb28f90ada88d91e80ea778868ec6ba.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 143, + 262, + 823, + 340 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/be704abe952894c6b599b1ebf742a1181d88cb9052b8cdf52b3f477a266eabd7.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 143, + 340, + 823, + 412 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/248f8285bdcd75d34422951ecac8f47d7ddb90f03201e31939368693fc5a7794.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 143, + 412, + 823, + 489 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c476038b4bc54ed56dbb362a7eb7aa27a0d178c4bd5df24c00362b2acd29e16e.jpg", + "image_caption": [ + "Figure 6 - Reconstruction of zero-shot scenes with multiple views. We sample several NYUv2 scenes for 3D reconstruction comparison. As our method can predict accurate metric depth, thus all predictions are fused together for scene reconstruction. By contrast, LeReS [57]'s depth is up to an unknown scale and shift, which causes noticeable distortions. DPSNet [17] is a multi-view stereo method, which cannot work well on low-texture regions." + ], + "image_footnote": [], + "bbox": [ + 143, + 489, + 823, + 563 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/49948a8e4b0e06a210056b0a94bbeaa9a5c8a3b86022e55370cb41b602d08e82.jpg", + "image_caption": [ + "Figure 7 - Reconstruction of in-the-wild scenes. We collect several Flickr photos, which are captured by various cameras. With photos' metadata, we reconstruct the 3D metric shape and measure structures' sizes. Red and blue marks are ours and ground-truth sizes respectively." + ], + "image_footnote": [], + "bbox": [ + 114, + 608, + 486, + 792 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "line ('Ours w/o LSTM') is to remove LSTM modules and enforce the same supervision as ours. Without LSTM, the model is unable to converge when training on mixed metric datasets and lost the metric prediction ability on zero-shot datasets. This is why mixed-data training methods compromise learning the affine-invariant depth to avoid metric issues. In contrast, our LSTM methods can enable the model to achieve the metric prediction ability, and they can achieve comparable performance. Tab. 1 also shows comparable performance. Therefore, both adjusting the supervision and the input image appearance during training can solve the metric ambiguity issues. Furthermore, we compare with CamConvs [11], which encodes the camera model in the decoder with a 4-channel feature. It employs the same training schedule, model, and training data as ours. This method enforces the network to implicitly understand various camera models from the image appearance and then bridges the imaging size to the real-world size. We believe that this", + "bbox": [ + 500, + 609, + 859, + 858 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "9049", + "bbox": [ + 483, + 888, + 513, + 898 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/1ba51a9a352893406fb8afc0021a6494bf7b6181a40f41d19cf17a7ef3ca19e1.jpg", + "table_caption": [ + "Table 3 - Quantitative comparison with SOTA metric depth methods on 6 unseen benchmarks. For SOTA methods, we use their NYUv2 and KITTI models for indoor and outdoor scenes evaluation respectively, while we use the same model for all zero-shot testing." + ], + "table_footnote": [], + "table_body": "
MethodDIODE(Indoor) Indoor scenes (AbsRel↓/RMS↓)DIODE(Outdoor) Outdoor scenes (AbsRel↓/RMS↓)
Adabins [2]0.443 / 1.9630.212 / 0.9010.218 / 0.4280.865 / 10.351.271 / 6.1780.445 / 10.658
NewCRFs [59]0.404 / 1.8670.206 / 0.8610.240 / 0.4510.854 / 9.2280.890 / 5.0110.400 / 12.139
Ours_CSTM_label0.252 / 1.4400.160 / 0.5210.183 / 0.3630.414 / 6.9340.416 / 3.0170.154 / 7.097
Ours_CSTM_image0.268 / 1.4290.144 / 0.6460.189 / 0.3880.535 / 6.5070.342 / 2.9650.147 / 5.889
", + "bbox": [ + 165, + 146, + 802, + 220 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/c900d073706e61060171b7161f8194b9ca9df57ce89a8c550de5628292da4cc7.jpg", + "table_caption": [ + "Table 4 - Comparison with SOTA affine-invariant depth methods on 5 zero-shot transfer benchmarks. Our model significantly outperforms previous methods and sets new state-of-the-art. Following the benchmark setting, all methods have manually aligned the scale and shift." + ], + "table_footnote": [], + "table_body": "
MethodBackbone#ParamsNYUv2KITTIDIODEScanNetETH3DRank
AbsRel↓δ1↑AbsRel↓δ1↑AbsRel↓δ1↑AbsRel↓δ1↑AbsRel↓δ1↑
DiverseDepth [53]ResNeXt50 [50]25M0.1170.8750.1900.7040.3760.6310.1080.8820.2280.6947.7
MiDaS [32]ResNeXt10188M0.1110.8850.2360.6300.3320.7150.1110.8860.1840.7527.2
Leres [57]ResNeXt1010.0900.9160.1490.7840.2710.7660.0950.9120.1710.7775.4
Omnidata [9]ViT-base0.0740.9450.1490.8350.3390.7420.0770.9350.1660.7784.9
HDN [60]ViT-Large [8]306M0.0690.9480.1150.8670.2460.7800.0800.9390.1210.8333.7
DPT-large [31]ViT-Large0.0980.9030.100.9010.1820.7580.0780.9380.0780.9463.8
Ours LSTM_imageConvNeXt-large [26]198M0.0580.9630.0530.9650.2110.8250.0740.9420.0640.9651.3
Ours LSTM_labelConvNeXt-large0.0500.9660.0580.9700.2240.8050.0740.9410.0660.9641.8
", + "bbox": [ + 169, + 247, + 802, + 356 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/4e6ef86595b29ba66df345043145885f86e3d2c8330ce8a6cbb53fdfaf1e0da1.jpg", + "table_caption": [ + "Table 5 - Comparison with SOTA SLAM methods on KITTI. We input predicted metric depth to the Droid-SLAM [44] ('Droid+Ours'), which outperforms others by a large margin on trajectory accuracy." + ], + "table_footnote": [], + "table_body": "
MethodSeq 00Seq 02Seq 05Seq 06Seq 08Seq 09Seq 10
Translational RMS drift (frel, ↓) / Rotational RMS drift (rrel, ↓)
GeoNet [58]27.6/5.7242.24/6.1420.12/7.679.28/4.3418.59/7.8523.94/9.8120.73/9.1
VISO2-M [41]12.66/2.739.47/1.1915.1/3.656.8/1.9314.82/2.523.69/1.2521.01/3.26
ORB-V2 [28]11.43/0.5810.34/0.269.04/0.2614.56/0.2611.46/0.289.3/0.262.57/0.32
Droid [44]33.9/0.2934.88/0.2723.4/0.2717.2/0.2639.6/0.3121.7/0.237/0.25
Droid+Ours1.44/0.372.64/0.291.44/0.250.6/0.22.2/0.31.63/0.222.73/0.23
", + "bbox": [ + 114, + 396, + 467, + 468 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/9378d8dbad38191232580891bfbeca6ddebd51a6d2c72d24aecb1eb759789bd6.jpg", + "table_caption": [ + "Table 6 - Effectiveness of our LSTM. CamConvs [11] directly encodes various camera models in the network, while we perform a simple yet effective transformation to solve the metric ambiguity. Without LSTM, the model cannot achieve transferable metric prediction ability." + ], + "table_footnote": [], + "table_body": "
MethodDDAD Test set of train.Lyft data (AbsRel↓)DSNS Zero-shot test setKITTI (AbsRel↓)NYU
w/o LSTM0.5300.5820.3941.000.5680.584
CamConvs [11]0.2950.3150.2130.4230.1780.333
Ours CSTM_image0.1900.2350.1820.1970.0970.210
Ours CSTM_label0.1830.2210.2010.2130.0810.212
", + "bbox": [ + 116, + 527, + 465, + 585 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "method challenges the data diversity and network capacity, thus our performance is better than theirs.", + "bbox": [ + 112, + 602, + 470, + 628 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Ablation on canonical space. We study the effect of the canonical camera here, i.e., the canonical focal length. We train the model on the small sampled dataset and test it on the validation set and testing data. The average AbsRel error is calculated. We experiment on 3 different focal lengths, i.e., 500, 1000, 1500. Experiments show that $\\text{focal} = 1000$ has slightly better performance than others, see Fig. 8. Thus we set the canonical focal length to 1000 in our experiments.", + "bbox": [ + 112, + 630, + 470, + 753 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Effectiveness of the random proposal normalization loss. To show the effectiveness of our proposed random proposal normalization loss (RPNL), we experiment on the sampled small dataset. Results are shown in Tab. 7. We test on the DDAD, Lyft, DrivingStereo (DS), NuScenes (NS), KITTI, and NYUv2. The 'baseline' employs all losses except our RPNL. We compare it with 'baseline + RPNL' and 'baseline + SSIL [32]'. We can observe that our proposed", + "bbox": [ + 112, + 756, + 472, + 866 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/f3b68f34b10e955b406332903e021da7291c37a39932bb3d224f61169b06a1f6.jpg", + "image_caption": [ + "Figure 8 - Effect of different canonical focal lengths. We experiment on different canonical focal lengths and find that too large or small focal lengths will impact the performance." + ], + "image_footnote": [], + "bbox": [ + 565, + 359, + 792, + 444 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/c4a3e8f94ba2d4962a6b9386c4552f5ec2d1917767381b8dfd25af9049caedca.jpg", + "table_caption": [ + "Table 7 - Effectiveness of random proposal normalization loss. Baseline is supervised by $L_{\\mathrm{PWN}} + L_{\\mathrm{VNL}} + L_{\\mathrm{silog}}$ . SSL is the scale-shift invariant loss proposed in [32]." + ], + "table_footnote": [], + "table_body": "
MethodDDAD Test set of train.Lyft data (AbsRel↓)DSNS Zero-shot test setKITTI (AbsRel↓)NYUv2
baseline0.2040.2510.1840.2070.1040.230
baseline + SSL [32]0.1970.2630.2590.2060.1050.216
baseline + RPNL0.1900.2350.1820.1970.0970.210
", + "bbox": [ + 503, + 523, + 856, + 574 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "random proposal normalization loss can further improve the performance. In contrast, the scale-shift invariant loss [32], which does the normalization on the whole image, can only slightly improve the performance.", + "bbox": [ + 500, + 578, + 857, + 633 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 648, + 607, + 662 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "In this paper, we tackle the problem of reconstructing the 3D metric scene from a single monocular image. To solve the depth ambiguity in image appearance caused by various focal lengths, we propose a canonical camera space transformation method. With our method, we can easily merge millions of data captured by 10k cameras to train one metric depth model. To improve the robustness, we collected over 8M data for training. Several zero-shot evaluations show the effectiveness and robustness of our work. We further show the ability to do metrology on randomly collected internet images and dense mapping on large-scale scenes.", + "bbox": [ + 496, + 672, + 859, + 823 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgements This work was in part supported by National Key R&D Program of China (No. 2022ZD0118700).", + "bbox": [ + 500, + 825, + 857, + 866 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "9050", + "bbox": [ + 483, + 888, + 513, + 898 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 114, + 125, + 200, + 138 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Jonathan T Barron and Jitendra Malik. Shape, illumination, and reflectance from shading. IEEE Trans. Pattern Anal. Mach. Intell., 37(8):1670-1687, 2014. 3", + "[2] Shariq Farooq Bhat, Ibrahim Alhashim, and Peter Wonka. Adabins: Depth estimation using adaptive bins. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 4009-4018, 2021. 2, 3, 6, 8", + "[3] Jia-Wang Bian, Huangying Zhan, Naiyan Wang, Tat-Jin Chin, Chunhua Shen, and Ian Reid. Auto-rectify network for unsupervised indoor depth estimation. IEEE Trans. Pattern Anal. Mach. Intell., 2021. 6, 7", + "[4] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 11621-11631, 2020. 5", + "[5] Weifeng Chen, Zhao Fu, Dawei Yang, and Jia Deng. Single-image depth perception in the wild. In Proc. Advances in Neural Inf. Process. Syst., pages 730-738, 2016. 2, 3", + "[6] Weifeng Chen, Shengyi Qian, David Fan, Noriyuki Kojima, Max Hamilton, and Jia Deng. Oasis: A large-scale dataset for single image 3d in the wild. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 679-688, 2020. 2, 3", + "[7] Angela Dai, Angel X Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 5828-5839, 2017. 5", + "[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. Proc. Int. Conf. Learn. Representations, 2021. 8", + "[9] Ainaz Eftekhar, Alexander Sax, Jitendra Malik, and Amir Zamir. Omnidata: A scalable pipeline for making multi-task mid-level vision datasets from 3d scans. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 10786-10796, 2021. 3, 8", + "[10] David Eigen, Christian Puhrsch, and Rob Fergus. Depth map prediction from a single image using a multi-scale deep network. In Proc. Advances in Neural Inf. Process. Syst., pages 2366-2374, 2014. 3, 5", + "[11] Jose Facil, Benjamin Ummenhofer, Huizhong Zhou, Luis Montesano, Thomas Brox, and Javier Civera. CAM-Convs: camera-aware multi-scale convolutions for single-view depth. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 11826-11835, 2019. 2, 7, 8", + "[12] Andreas Geiger, Philip Lenz, Christoph Stiller, and Raquel Urtasun. Vision meets robotics: The kitti dataset. Int. J. Robot. Res., 2013. 3, 5, 6", + "[13] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the kitti vision benchmark suite. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 3354-3361. IEEE, 2012. 6", + "[14] Xiaoyang Guo, Hongsheng Li, Shuai Yi, Jimmy Ren, and Xiaogang Wang. Learning monocular depth by distilling" + ], + "bbox": [ + 114, + 147, + 472, + 867 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "cross-domain stereo networks. In Proc. Eur. Conf. Comp. Vis., pages 484-500, 2018. 6", + "[15] Richard Hartley and Andrew Zisserman. Multiple view geometry in computer vision. Cambridge university press, 2003. 2", + "[16] Yannick Hold-Geoffroy, Kalyan Sunkavalli, Jonathan Eisenmann, Matthew Fisher, Emiliano Gambaretto, Sunil Hadap, and Jean-François Lalonde. A perceptual measure for deep single image camera calibration. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2354-2363, 2018. 4", + "[17] Sunghoon Im, Hae-Gon Jeon, Stephen Lin, and In-So Kweon. Dpsnet: End-to-end deep plane sweep stereo. In Proc. Int. Conf. Learn. Representations, 2019. 3, 6, 7", + "[18] Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: Benchmarking large-scale scene reconstruction. ACM Trans. Graph., 36(4):1-13, 2017. 5", + "[19] Tobias Koch, Lukas Liebel, Friedrich Fraundorfer, and Marco Korner. Evaluation of cnn-based single-image depth estimation methods. In *Eur. Conf. Comput. Vis. Worksh.*, pages 0–0, 2018. 5", + "[20] Johannes Kopf, Xuejian Rong, and Jia-Bin Huang. Robust consistent video depth estimation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2021. 6, 7", + "[21] Iro Laina, Christian Rupprecht, Vasileios Belagiannis, Federico Tombari, and Nassir Navab. Deeper depth prediction with fully convolutional residual networks. In 2016 Fourth international conference on 3D vision (3DV), pages 239-248. IEEE, 2016. 6", + "[22] John Lambert, Zhuang Liu, Ozan Sener, James Hays, and Vladlen Koltun. Mseg: A composite dataset for multi-domain semantic segmentation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2879-2888, 2020. 3", + "[23] Jun Li, Reinhard Klein, and Angela Yao. A two-streamed network for estimating fine-scaled depth maps from singlergb images. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 3372-3380, 2017. 6", + "[24] Shunkai Li, Xin Wu, Yingdian Cao, and Hongbin Zha. Generalizing to the open world: Deep visual odometry with online adaptation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 13184-13193, 2021. 5", + "[25] Yifan Liu, Hao Chen, Yu Chen, Wei Yin, and Chunhua Shen. Generic perceptual loss for modeling structured output dependencies. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2021. 3", + "[26] Zhuang Liu, Hanzi Mao, Chao-Yuan Wu, Christoph Feichtenhofer, Trevor Darrell, and Saining Xie. A convnet for the 2020s. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 11976-11986, 2022. 5, 8", + "[27] Raul Mur-Artal and Juan D Tardós. Orb-slam2: An open-source slam system for monocular, stereo, and rgb-d cameras. IEEE transactions on robotics, 33(5):1255-1262, 2017. 3", + "[28] Raul Mur-Artal and Juan D. Tardós. ORB-SLAM2: an open-source SLAM system for monocular, stereo and RGB-D cameras. IEEE Trans. Robot., 33(5):1255-1262, 2017. 8", + "[29] Sida Peng, Shangzhan Zhang, Zhen Xu, Chen Geng, Boyi Jiang, Hujun Bao, and Xiaowei Zhou. Animatable neural" + ], + "bbox": [ + 501, + 127, + 856, + 866 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "9051", + "bbox": [ + 483, + 888, + 511, + 898 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "implicit surfaces for creating avatars from videos. arXiv: Comp. Res. Repository, page 2203.08133, 2022. 2", + "[30] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In Proc. Int. Conf. Mach. Learn., pages 8748-8763. PMLR, 2021. 3", + "[31] René Ranftl, Alexey Bochkovskiy, and Vladlen Koltun. Vision transformers for dense prediction. In Proc. IEEE Int. Conf. Comp. Vis., pages 12179-12188, 2021. 2, 6, 7, 8", + "[32] René Ranftl, Katrin Lasinger, David Hafner, Konrad Schindler, and Vladlen Koltun. Towards robust monocular depth estimation: Mixing datasets for zero-shot cross-dataset transfer. IEEE Trans. Pattern Anal. Mach. Intell., 2020. 2, 3, 5, 8", + "[33] Shunsuke Saito, Zeng Huang, Ryota Natsume, Shigeo Morishima, Angjoo Kanazawa, and Hao Li. Pifu: Pixel-aligned implicit function for high-resolution clothed human digitization. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2304-2314, 2019. 3", + "[34] Shunsuke Saito, Tomas Simon, Jason Saragih, and Hanbyul Joo. Pifuhd: Multi-level pixel-aligned implicit function for high-resolution 3d human digitization. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 84-93, 2020. 3", + "[35] Ashutosh Saxena, Min Sun, and Andrew Y Ng. Make3d: Learning 3d scene structure from a single still image. IEEE Trans. Pattern Anal. Mach. Intell., 31(5):824-840, 2008. 3", + "[36] Johannes Lutz Schonberger, Enliang Zheng, Marc Pollefeys, and Jan-Michael Frahm. Pixelwise view selection for unstructured multi-view stereo. In Proc. Eur. Conf. Comp. Vis., 2016. 5", + "[37] Thomas Schops, Johannes L Schonberger, Silvano Galliani, Torsten Sattler, Konrad Schindler, Marc Pollefeys, and Andreas Geiger. A multi-view stereo benchmark with high-resolution images and multi-camera videos. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 3260-3269, 2017. 5", + "[38] Jamie Shotton, Ben Glocker, Christopher Zach, Shahram Izadi, Antonio Criminisi, and Andrew Fitzgibbon. Scene coordinate regression forests for camera relocalization in rgb-d images. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2930-2937, 2013. 5", + "[39] Nathan Silberman, Derek Hoiem, Pushmeet Kohli, and Rob Fergus. Indoor segmentation and support inference from rgbd images. In Proc. Eur. Conf. Comp. Vis., pages 746-760. Springer, 2012. 3, 5, 6", + "[40] Dalwinder Singh and Birmohan Singh. Investigating the impact of data normalization on classification performance. Applied Soft Computing, 2019. 5", + "[41] Shiyu Song, Manmohan Chandraker, and Clark C Guest. High accuracy monocular sfm and scale correction for autonomous driving. IEEE Trans. Pattern Anal. Mach. Intell., 38(4):730-743, 2015. 8", + "[42] Jaime Spencer, C. Stella Qian, Michaela Trescakova, Chris Russell, Simon Hadfield, Erich W. Graf, Wendy J. Adams, Andrew J. Schofield, James Elder, Richard Bowden, Ali Anwar, Hao Chen, Xiaozhi Chen, Kai Cheng, Yuchao Dai," + ], + "bbox": [ + 116, + 127, + 470, + 866 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Huynh Thai Hoa, Sadat Hossain, Jianmian Huang, Mohan Jing, Bo Li, Chao Li, Baojun Li, Zhiwen Liu, Stefano Mattoccia, Siegfried Mercelis, Myungwoo Nam, Matteo Poggi, Xiaohua Qi, Jiahui Ren, Yang Tang, Fabio Tosi, Linh Trinh, S. M. Nadim Uddin, Khan Muhammad Umair, Kaixuan Wang, Yufei Wang, Yixing Wang, Mochu Xiang, Guangkai Xu, Wei Yin, Jun Yu, Qi Zhang, and Chaoqiang Zhao. The second monocular depth estimation challenge. In IEEE Conf. Comput. Vis. Pattern Recog. Worksh., pages 3063-3075, June 2023. 3", + "[43] Libo Sun, Wei Yin, Enze Xie, Zhengrong Li, Changming Sun, and Chunhua Shen. Improving monocular visual odometry using learned depth. IEEE Transactions on Robotics, 38(5):3173-3186, 2022. 3", + "[44] Zachary Teed and Jia Deng. Droid-slam: Deep visual slam for monocular, stereo, and rgb-d cameras. volume 34, pages 16558-16569, 2021. 1, 3, 6, 8", + "[45] Igor Vasiljevic, Nick Kolkin, Shanyi Zhang, Ruotian Luo, Haochen Wang, Falcon Z Dai, Andrea F Daniele, Mohammadreza Mostajabi, Steven Basart, Matthew R Walter, et al. Diode: A dense indoor and outdoor depth dataset. arXiv: Comp. Res. Repository, page 1908.00463, 2019. 5", + "[46] Nanyang Wang, Yinda Zhang, Zhuwen Li, Yanwei Fu, Wei Liu, and Yu-Gang Jiang. Pixel2mesh: Generating 3d mesh models from single RGB images. In Proc. Eur. Conf. Comp. Vis., pages 52-67, 2018. 3", + "[47] Jiajun Wu, Chengkai Zhang, Xiuming Zhang, Zhoutong Zhang, William Freeman, and Joshua Tenenbaum. Learning shape priors for single-view 3d completion and reconstruction. In Proc. Eur. Conf. Comp. Vis., pages 646-662, 2018. 3", + "[48] Ke Xian, Chunhua Shen, Zhiguo Cao, Hao Lu, Yang Xiao, Ruibo Li, and Zhenbo Luo. Monocular relative depth perception with web stereo data supervision. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 311-320, 2018. 2, 3", + "[49] Ke Xian, Jianming Zhang, Oliver Wang, Long Mai, Zhe Lin, and Zhiguo Cao. Structure-guided ranking loss for single image depth prediction. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 611-620, 2020. 2, 3", + "[50] Saining Xie, Ross Girshick, Piotr Dólar, Zhuowen Tu, and Kaiming He. Aggregated residual transformations for deep neural networks. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 1492-1500, 2017. 8", + "[51] Guangkai Xu, Wei Yin, Hao Chen, Chunhua Shen, Kai Cheng, and Feng Zhao. Pose-free 3d scene reconstruction with frozen depth models. In Proc. IEEE Int. Conf. Comp. Vis., 2023. 3", + "[52] Guanglei Yang, Hao Tang, Mingli Ding, Nicu Sebe, and Elisa Ricci. Transformer-based attention networks for continuous pixel-wise prediction. In Proc. IEEE Int. Conf. Comp. Vis., 2021. 2, 6", + "[53] Wei Yin, Yifan Liu, and Chunhua Shen. Virtual normal: Enforcing geometric constraints for accurate and robust depth prediction. IEEE Trans. Pattern Anal. Mach. Intell., 2021. 2, 3, 5, 8", + "[54] Wei Yin, Yifan Liu, Chunhua Shen, Anton van den Hengel, and Baichuan Sun. The devil is in the labels: Semantic seg" + ], + "bbox": [ + 503, + 127, + 857, + 866 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "9052", + "bbox": [ + 483, + 888, + 513, + 898 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "mentation from sentences. arXiv: Comp. Res. Repository, page 2202.02002, 2022.3", + "[55] Wei Yin, Yifan Liu, Chunhua Shen, and Youliang Yan. Enforcing geometric constraints of virtual normal for depth prediction. In Proc. IEEE Int. Conf. Comp. Vis., 2019. 2, 3, 6", + "[56] Wei Yin, Jianming Zhang, Oliver Wang, Simon Niklaus, Simon Chen, Yifan Liu, and Chunhua Shen. Towards accurate reconstruction of 3d scene shape from a single monocular image. IEEE Trans. Pattern Anal. Mach. Intell., 2022. 2, 3", + "[57] Wei Yin, Jianming Zhang, Oliver Wang, Simon Niklaus, Long Mai, Simon Chen, and Chunhua Shen. Learning to recover 3d scene shape from a single image. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2021. 1, 2, 3, 4, 5, 6, 7, 8", + "[58] Zhichao Yin and Jianping Shi. Geonet: Unsupervised learning of dense depth, optical flow and camera pose. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1983-1992, 2018. 8", + "[59] Weihao Yuan, Xiaodong Gu, Zuozhuo Dai, Siyu Zhu, and Ping Tan. New CRFs: Neural window fully-connected CRFs for monocular depth estimation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2022. 2, 3, 6, 8", + "[60] Chi Zhang, Wei Yin, Zhibin Wang, Gang Yu, Bin Fu, and Chunhua Shen. Hierarchical normalization for robust monocular depth estimation. Proc. Advances in Neural Inf. Process. Syst., 2022. 2, 3, 5, 8", + "[61] Chi Zhang, Wei Yin, Gang Yu, Zhibin Wang, Tao Chen, Bin Fu, Joey Tianyi Zhou, and Chunhua Shen. Robust geometry-preserving depth estimation using differentiable rendering. In Proc. IEEE Int. Conf. Comp. Vis., 2023. 3", + "[62] Rui Zhu, Xingyi Yang, Yannick Hold-Geoffroy, Federico Perazzi, Jonathan Eisenmann, Kalyan Sunkavalli, and Manmohan Chandraker. Single view metrology in the wild. In Proc. Eur. Conf. Comp. Vis., pages 316-333. Springer, 2020." + ], + "bbox": [ + 116, + 127, + 472, + 554 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "9053", + "bbox": [ + 483, + 888, + 513, + 898 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/6cc2d292-7284-48d5-98ac-76d175845d01_model.json b/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/6cc2d292-7284-48d5-98ac-76d175845d01_model.json new file mode 100644 index 0000000000000000000000000000000000000000..212a5434240637cf49f6db97a7eed2050bb9d9fa --- /dev/null +++ b/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/6cc2d292-7284-48d5-98ac-76d175845d01_model.json @@ -0,0 +1,2246 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.14, + 0.046, + 0.209, + 0.082 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.261, + 0.044, + 0.782, + 0.058 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation." + }, + { + "type": "header", + "bbox": [ + 0.338, + 0.058, + 0.704, + 0.071 + ], + "angle": 0, + "content": "Except for this watermark, it is identical to the accepted version;" + }, + { + "type": "header", + "bbox": [ + 0.31, + 0.071, + 0.733, + 0.085 + ], + "angle": 0, + "content": "the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.15, + 0.162, + 0.823, + 0.184 + ], + "angle": 0, + "content": "Metric3D: Towards Zero-shot Metric 3D Prediction from A Single Image" + }, + { + "type": "text", + "bbox": [ + 0.18, + 0.207, + 0.794, + 0.24 + ], + "angle": 0, + "content": "Wei Yin\\(^{1*}\\), Chi Zhang\\(^{2*}\\), Hao Chen\\(^{3\\dagger}\\), Zhipeng Cai\\(^{4}\\), Gang Yu\\(^{2}\\), Kaixuan Wang\\(^{1}\\), Xiaozhi Chen\\(^{1}\\), Chunhua Shen\\(^{3}\\)" + }, + { + "type": "text", + "bbox": [ + 0.221, + 0.244, + 0.753, + 0.262 + ], + "angle": 0, + "content": "\\(^{1}\\) DJI Technology \\(^{2}\\) Tencent \\(^{3}\\) Zhejiang University \\(^{4}\\) Intel Labs" + }, + { + "type": "text", + "bbox": [ + 0.194, + 0.262, + 0.779, + 0.278 + ], + "angle": 0, + "content": "e-mail: \\(^1\\mathrm{yvanwy}\\) @outlook.com,{halfbullet.wang,xiaozhi.chen} \\(@\\) dji.com;" + }, + { + "type": "text", + "bbox": [ + 0.334, + 0.278, + 0.641, + 0.294 + ], + "angle": 0, + "content": "\\(^{2}\\)johnczhang, skicyyu@tencent.com;" + }, + { + "type": "text", + "bbox": [ + 0.214, + 0.294, + 0.76, + 0.31 + ], + "angle": 0, + "content": "3haochen.cad@zju.edu.cn, chunhua@me.com; 4zhipeng.cai@intel.com" + }, + { + "type": "image", + "bbox": [ + 0.153, + 0.342, + 0.823, + 0.64 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.118, + 0.648, + 0.855, + 0.715 + ], + "angle": 0, + "content": "Figure 1 - Illustration and applications of our metric 3D reconstruction method. Top (metrology): we use two phones (iPhone 12 and an Android phone) to capture the scene and measure the size of tables. With the photos' metadata, we perform 3D metric reconstruction and then measure tables' sizes (marked in red), which are very close to the ground truth (marked in blue). In contrast, the recent method LeReS [57] performs much worse and is unable to predict metric 3D by design. Bottom (dense SLAM mapping): existing SOTA mono-SLAM methods usually face scale drift problems (see the red arrows) in large-scale scenes and are unable to achieve the metric scale, while, naively inputting our metric depth, Droid-SLAM [44] can recover much more accurate trajectory and perform the metric dense mapping (see the red measurements). Note that all testing data are unseen to our model." + }, + { + "type": "title", + "bbox": [ + 0.258, + 0.728, + 0.33, + 0.743 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.113, + 0.759, + 0.473, + 0.829 + ], + "angle": 0, + "content": "Reconstructing accurate 3D scenes from images is a long-standing vision task. Due to the ill-posedness of the single-image reconstruction problem, most well-established methods are built upon multi-view geometry. State-of-the-art (SOTA) monocular metric depth estimation meth" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.73, + 0.861, + 0.855 + ], + "angle": 0, + "content": "ods can only handle a single camera model and are unable to perform mixed-data training due to metric ambiguity. Meanwhile, SOTA monocular methods trained on large mixed datasets achieve zero-shot generalization by learning affine-invariant depths, which cannot recover real-world metrics. In this work, we show that the key to a zero-shot single-view metric depth model lies in the combination of large-scale data training and resolving the metric ambiguity from various camera models. We propose a" + }, + { + "type": "page_footnote", + "bbox": [ + 0.131, + 0.844, + 0.236, + 0.855 + ], + "angle": 0, + "content": "*Equal contributions." + }, + { + "type": "page_footnote", + "bbox": [ + 0.133, + 0.855, + 0.246, + 0.867 + ], + "angle": 0, + "content": "†Corresponding author." + }, + { + "type": "list", + "bbox": [ + 0.131, + 0.844, + 0.246, + 0.867 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.89, + 0.514, + 0.901 + ], + "angle": 0, + "content": "9043" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.111, + 0.127, + 0.474, + 0.389 + ], + "angle": 0, + "content": "canonical camera space transformation module, which explicitly addresses the ambiguity problems and can be effortlessly plugged into existing monocular models. Equipped with our module, monocular models can be stably trained over 8 millions of images with thousands of camera models, resulting in zero-shot generalization to in-the-wild images with unseen camera settings. Experiments demonstrate SOTA performance of our method on 7 zero-shot benchmarks. Notably, our method won the championship in the 2nd Monocular Depth Estimation Challenge. Our method enables the accurate recovery of metric 3D structures on randomly collected internet images, paving the way for plausible single-image metrology. The potential benefits extend to downstream tasks, which can be significantly improved by simply plugging in our model. For example, our model relieves the scale drift issues of monocular-SLAM (Fig. 1), leading to high-quality metric scale dense mapping. The code is available at https://github.com/YvanYin/Metric3D." + }, + { + "type": "title", + "bbox": [ + 0.115, + 0.416, + 0.236, + 0.43 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.111, + 0.439, + 0.475, + 0.646 + ], + "angle": 0, + "content": "3D reconstruction from images is the core of many computer vision applications, such as autonomous driving and robotics. Main-stream methods leverage multi-view geometry [15] to confidently recover 3D structures. However, these methods cannot be applied to a single image, making 3D reconstruction hard without a prior. State-of-the-art transferable methods, such as MiDaS [32], LeReS [57], and HDN [60], learn such a prior from a large dataset, but they can only output affine-invariant depths, i.e., which are accurate only up to an unknown offset and scale. Though monocular metric depth estimation methods [59, 2] work on a single dataset with a single camera model, they cannot generalize to unseen cameras or scenes. This work aims to address the above problems by learning a zero-shot, single view, metric depth model." + }, + { + "type": "text", + "bbox": [ + 0.111, + 0.647, + 0.474, + 0.868 + ], + "angle": 0, + "content": "According to the predicted depth, existing methods are categorized into learning metric depth [59, 53, 2, 52], learning relative depth [48, 49, 6, 5], and learning affine-invariant depth [57, 56, 32, 31, 60]. Although the metric depth methods [59, 53, 55, 2, 52] have achieved impressive accuracy on various benchmarks, they must train and test on the dataset with the same camera intrinsics. Therefore, training datasets of metric depth methods are often small, as it is hard to collect a large dataset covering diverse scenes using one identical camera. The consequence is that all these models are not transferable - they generalize poorly to images in the wild, not to mention the camera parameters of test images can vary too. A compromise is to learn the relative depth [6, 48], which only represents the depth ordering information. Thus the application is very limited. Learning affine-invariant depth finds a trade-off between the above" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.127, + 0.86, + 0.196 + ], + "angle": 0, + "content": "two categories of methods. With large-scale data, they decouple the metric information during training and achieve impressive robustness and generalization ability. The recent SOTA LeReS [57] can recover 3D scenes in the wild, but only up to an unknown scale and shift." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.199, + 0.861, + 0.768 + ], + "angle": 0, + "content": "This work focuses on learning a zero-shot transferable model to recover metric 3D from a single image. First, we analyze the metric ambiguity issues in monocular depth estimation and study different camera parameters in depth, including the pixel size, focal length, and sensor size. We observe that the focal length is the critical factor for accurate metric recovery. By design, LeReS [57] does not take the focal length information into account during training. As shown in Sec. 3.1, only from the image appearance, various focal lengths may cause metric ambiguity, thus they decouple the depth scale in training. To solve the problem of varying focal lengths, CamConv [11] encodes the camera model in the network, which enforces the network to implicitly understand camera models from the image appearance and then bridges the imaging size to the real-world size. However, training data contains limited images and types of cameras, which challenges data diversity and network capacity. In contrast, we propose a canonical camera transformation method in training. It is inspired by the human body reconstruction methods. To improve reconstructed shape quality on countless poses, they map all samples to a canonical pose space [29] to reduce pose variance. Similarly, we transform all training data to a canonical camera space where the processed images are coarsely regarded as captured by the same camera. To achieve such transformation, we propose two different methods. The first one tries to adjust the image appearance to simulate the canonical camera, while the other one transforms the ground-truth labels for supervision. Camera models are not encoded in the network, making our method easily applicable to existing architectures. During inference, a de-canonical transformation is employed to recover metric information. To further boost the depth accuracy, we propose a random proposal normalization loss. It is inspired by the scale-shift invariant loss [57, 32, 60], which decouples the depth scale to emphasize the single image's distribution. However, they perform on the whole image, which inevitably squeezes the fine-grained depth difference. We propose to randomly crop several patches from images and enforce the scale-shift invariant loss [57, 32] on them. Our loss emphasizes the local geometry and distribution of the single image." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.77, + 0.862, + 0.869 + ], + "angle": 0, + "content": "With the proposed method, we can easily scale up model training to 8 million images from 11 datasets of diverse scene types (indoor and outdoor) and camera models (tens of thousands of different cameras), leading to zero-shot transferability and a significantly improved accuracy. Our model can accurately reconstruct metric 3D from randomly collected Internet images, enabling plausible single-image" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.89, + 0.516, + 0.902 + ], + "angle": 0, + "content": "9044" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.112, + 0.127, + 0.474, + 0.265 + ], + "angle": 0, + "content": "metrology. Different from affine-invariant depth models, our model can also directly improve various downstream tasks. As an example (Fig. 1), with the predicted metric depths from our model, we can significantly reduce the scale drift of monocular SLAM [44, 43] systems, achieving much better mapping quality with real-world metric recovery. Our model also enables large-scale 3D reconstruction [17]. The model achieves the championship in the 2nd Monocular Depth Estimation Challenge [42]. To summarize, our main contributions are:" + }, + { + "type": "text", + "bbox": [ + 0.13, + 0.275, + 0.474, + 0.344 + ], + "angle": 0, + "content": "- We propose a canonical and de-canonical camera transformation method to solve the metric depth ambiguity problems from various cameras setting. It enables the learning of strong zero-shot monocular metric depth models from large-scale datasets." + }, + { + "type": "text", + "bbox": [ + 0.131, + 0.346, + 0.473, + 0.373 + ], + "angle": 0, + "content": "- We propose a random proposal normalization loss to boost the depth accuracy effectively;" + }, + { + "type": "text", + "bbox": [ + 0.131, + 0.375, + 0.474, + 0.445 + ], + "angle": 0, + "content": "- Our model achieves state-of-the-art performance on 7 zero-shot benchmarks. It can perform high-quality 3D metric structure recovery in the wild and benefit several downstream tasks, such as mono-SLAM [44, 27], 3D scene reconstruction [17], and metrology [62]." + }, + { + "type": "list", + "bbox": [ + 0.13, + 0.275, + 0.474, + 0.445 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.114, + 0.457, + 0.245, + 0.47 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.112, + 0.48, + 0.474, + 0.797 + ], + "angle": 0, + "content": "3D reconstruction from a single image. Reconstructing various objects from a single image has been well studied [1, 46, 47]. They can produce high-quality 3D models of cars, planes, tables, and human body [33, 34]. The main challenge is how to best recover objects' details, how to represent them with limited memory, and how to generalize to more diverse objects. However, all these methods rely on learning priors specific to a certain object class or instance, typically from 3D supervision, and can therefore not work for full scene reconstruction. Apart from these reconstructing objects works, several works focus on scene reconstruction [51] from a single image. Saxena et al. [35] construct the scene based on the assumption that the whole scene can be segmented into several small planes. With planes' orientation and location, the 3D structure can be represented. Recently, LeReS [57] propose to use a strong monocular depth estimation model to do scene reconstruction. However, they can only recover the shape up to a scale. Zhang et al. [61] recently propose a zero-shot geometry-preserving depth estimation model that is capable of making depth predictions up to an unknown scale, without requiring scale-invariant depth annotations for training. In contrast to these works, our method can recover the metric 3D structure." + }, + { + "type": "text", + "bbox": [ + 0.112, + 0.798, + 0.474, + 0.868 + ], + "angle": 0, + "content": "Supervised monocular depth estimation. After several benchmarks [39, 12] are established, neural network based methods [59, 55, 2, 25] have dominated since then. Several approaches regress the continuous depth from the aggregation of information in an image [10]. As depth distribution" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.127, + 0.86, + 0.417 + ], + "angle": 0, + "content": "corresponding to different RGBs can vary to a large extent, some methods [55, 2] discretize the depth and formulate this problem to a classification [53], which often achieves better performance. The generalization issue of deep models for 3D metric recovery is related to two problems. The first one is to generalize to diverse scenes, while the other one is how to predict accurate metric information under various camera settings. The first problem has been well addressed by recent methods. Some works [49, 48, 53] propose to construct a large-scale relative depth dataset, such as DIW [5] and OASIS [6], and then they target learning the relative relations. However, the relative depth loses geometric structure information. To improve the recovered geometry quality, learning affine-invariant depth methods, such as MiDaS [32], LeReS [57], and HDN [60] are proposed. By mixing large-scale data, state-of-the-art performance and the generalization over scenes are improved continuously. Note that by design, these methods are unable to recover the metric information. How to achieve both strong generalization and accurate metric information over diverse scenes is the key problem that we attempt to tackle." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.418, + 0.861, + 0.584 + ], + "angle": 0, + "content": "Large-scale data training. Recently, various natural language problems and computer vision problems [54, 30, 22] have achieved impressive progress with large-scale data training. CLIP [30] is a promising classification model, which is trained on billions of paired image and language descriptions data. It achieved state-of-the-art performance over several classification benchmarks by zero-shot testing. For depth prediction, large-scale data training has been widely applied. Ranft et al. [32] mixed over 2 million data in training, LeReS [56] collected over 300 thousand data, Eftekhar et al. [9] also merged millions of data to build a strong depth prediction model." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.599, + 0.585, + 0.615 + ], + "angle": 0, + "content": "3. Method" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.624, + 0.86, + 0.709 + ], + "angle": 0, + "content": "Preliminaries. We consider the pin-hole camera model with intrinsic parameters: \\([[\\hat{f} /\\delta ,0,u_0],[0,\\hat{f} /\\delta ,v_0],[0,0,1]]\\) where \\(\\hat{f}\\) is the focal length (in micrometers), \\(\\delta\\) is the pixel size (in micrometers), and \\((u_0,v_0)\\) is the principle center. \\(f = \\hat{f} /\\delta\\) is the pixel-represented focal length used in vision algorithms." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.72, + 0.724, + 0.736 + ], + "angle": 0, + "content": "3.1. Metric Ambiguity Analysis" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.743, + 0.861, + 0.868 + ], + "angle": 0, + "content": "Fig. 3 presents an example of photos taken by different cameras and at different distances. Only from the image's appearance, one may think the last two photos are taken at a similar location by the same camera. In fact, due to different focal lengths, these are captured at different locations. Thus, camera intrinsic parameters are critically important for the metric estimation from a single image, as otherwise, the problem is ill posed. To avoid such metric ambiguity, recent methods, such as MiDaS [32] and LeReS [57]," + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.89, + 0.516, + 0.901 + ], + "angle": 0, + "content": "9045" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.149, + 0.125, + 0.82, + 0.244 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.118, + 0.245, + 0.855, + 0.29 + ], + "angle": 0, + "content": "Figure 2 - Pipeline. Given an input image \\( I \\), we first transform it to the canonical space using CSTM. The transformed image \\( I_{c} \\) is fed into a depth estimation model to produce the metric depth \\( D_{c} \\) in the canonical space. During training, \\( D_{c} \\) is supervised by a GT depth \\( D_{c}^{*} \\) which is also transformed into the canonical space. In inference, after producing the metric depth \\( D_{c} \\) in the canonical space, we perform a de-canonical transformation to convert it back to the space of the original input \\( I \\). The canonical and de-canonical transformations are executed using camera intrinsics." + }, + { + "type": "image", + "bbox": [ + 0.117, + 0.3, + 0.233, + 0.395 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.12, + 0.396, + 0.226, + 0.405 + ], + "angle": 0, + "content": "focal=26mm,depth=2m" + }, + { + "type": "image", + "bbox": [ + 0.234, + 0.3, + 0.349, + 0.395 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.24, + 0.396, + 0.343, + 0.405 + ], + "angle": 0, + "content": "focal=52mm,depth=2m" + }, + { + "type": "image", + "bbox": [ + 0.349, + 0.3, + 0.466, + 0.395 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.356, + 0.396, + 0.461, + 0.405 + ], + "angle": 0, + "content": "focal=26mm,depth=1m" + }, + { + "type": "image_caption", + "bbox": [ + 0.119, + 0.409, + 0.467, + 0.453 + ], + "angle": 0, + "content": "Figure 3 - Photos of a chair captured at different distances with different cameras. The first two photos are captured at the same distance but with different cameras, while the last one is taken at a closer distance with the same camera as the first one." + }, + { + "type": "text", + "bbox": [ + 0.113, + 0.458, + 0.471, + 0.485 + ], + "angle": 0, + "content": "decouple the metric from the supervision and compromise learning the affine-invariant depth." + }, + { + "type": "text", + "bbox": [ + 0.113, + 0.486, + 0.472, + 0.527 + ], + "angle": 0, + "content": "Fig. 4 (A) shows a simple pin-hole perspective projection. Object \\( A \\) locating at \\( d_{a} \\) is projected to \\( A^{\\prime} \\). Based on the principle of similarity, we have the equation:" + }, + { + "type": "equation", + "bbox": [ + 0.226, + 0.535, + 0.472, + 0.565 + ], + "angle": 0, + "content": "\\[\nd _ {a} = \\hat {S} \\left[ \\frac {\\hat {f}}{\\hat {S} ^ {\\prime}} \\right] = \\hat {S} \\cdot \\alpha \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.112, + 0.562, + 0.472, + 0.756 + ], + "angle": 0, + "content": "where \\(\\hat{S}\\) and \\(\\hat{S}^{\\prime}\\) are the real and imaging size respectively. \\(\\hat{\\tau}\\) denotes variables are in the physical metric (e.g., millimeter). To recover \\(d_{a}\\), focal length, imaging size of the object, and real-world object size must be available. Estimating the focal length from a single image is a challenging and ill-posed problem. Although several methods [57, 16] have been explored, the accuracy is still far from being satisfactory. Here, we simplify the problem by assuming the focal length of a training/test image is available. Understanding the imaging size is much easier for a neural network. To obtain the real-world object size, a neural network needs to understand the semantic scene layout and the object, at which a neural network excels. We define \\(\\alpha = \\hat{f} / \\hat{s}^{\\prime}\\), so \\(d_{a}\\) is proportional to \\(\\alpha\\)." + }, + { + "type": "text", + "bbox": [ + 0.113, + 0.757, + 0.473, + 0.784 + ], + "angle": 0, + "content": "We make the following observations regarding sensor size, pixel size, and focal length." + }, + { + "type": "text", + "bbox": [ + 0.113, + 0.785, + 0.473, + 0.867 + ], + "angle": 0, + "content": "O1: Sensor size and pixel size do not affect the metric depth estimation. Based on the perspective projection (Fig. 4 (A)), the sensor size only affects the field of view (FOV) and is irrelevant to \\(\\alpha\\), thus does not affect the metric depth estimation. For the pixel size, we assume two cameras with different pixel sizes (\\(\\delta_{1} = 2\\delta_{2}\\)) but the same focal" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.301, + 0.859, + 0.417 + ], + "angle": 0, + "content": "length \\(\\hat{f}\\) to capture the same object locating at \\(d_{a}\\). Fig. 4 (B) shows their captured photos. According to the preliminaries, the pixel-represented focal length \\(f_{1} = \\frac{1}{2} f_{2}\\). As the second camera has a smaller pixel size, although in the same projected imaging size \\(\\hat{S}'\\), the pixel-represented image resolution is \\(S_1' = \\frac{1}{2} S_2'\\). According to Eq. (1), \\(\\frac{\\hat{f}}{\\delta_1 \\cdot S_1'} = \\frac{\\hat{f}}{\\delta_2 \\cdot S_2'}\\), i.e. \\(\\alpha_{1} = \\alpha_{2}\\), so \\(d_{1} = d_{2}\\). Therefore, different camera sensors would not affect the metric depth estimation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.418, + 0.859, + 0.528 + ], + "angle": 0, + "content": "O2: The focal length is vital for metric depth estimation. Fig. 3 shows the metric ambiguity issue caused by the unknown focal length. In Fig. 5, two cameras \\((\\hat{f}_1 = 2\\hat{f}_2)\\) are at distances \\(d_{1}\\) and \\(d_{2}\\), the imaging sizes on cameras are the same. Only from the appearance, the network will be confused when supervised with different labels. Based on this, we propose a canonical camera transformation method to solve the supervision and image appearance conflicts." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.539, + 0.78, + 0.552 + ], + "angle": 0, + "content": "3.2. Canonical Camera Transformation" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.561, + 0.859, + 0.643 + ], + "angle": 0, + "content": "The core idea is to set up a canonical camera space \\(((f_x^c, f_y^c), f_x^c = f_y^c = f^c\\) in experiments) and transform all training data to this space. Consequently, all data can roughly be regarded as captured by the canonical camera. We propose two transformation methods, i.e. either on the input image \\((\\mathbf{I} \\in \\mathbb{R}^{H \\times W \\times 3})\\) or the GT label \\((\\mathbf{D} \\in \\mathbb{R}^{H \\times W})\\)." + }, + { + "type": "image", + "bbox": [ + 0.512, + 0.643, + 0.66, + 0.717 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.66, + 0.643, + 0.848, + 0.716 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.505, + 0.725, + 0.854, + 0.771 + ], + "angle": 0, + "content": "Figure 4 - Pinhole camera model. (A) Object \\( A \\) at the distance \\( d_{a} \\) is projected to the image plane. (B) Using two cameras to capture the car. The left one has a larger pixel size. Although the projected imaging sizes are the same, the pixel-represented images (resolution) are different." + }, + { + "type": "image", + "bbox": [ + 0.51, + 0.779, + 0.85, + 0.842 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.505, + 0.851, + 0.853, + 0.887 + ], + "angle": 0, + "content": "Figure 5 - Illustration of two cameras with different focal length at different distance. As \\( f_{1} = 2f_{2} \\) and \\( d_{1} = 2d_{2} \\), \\( A \\) is projected to two image planes with the same imaging size (i.e. \\( A_{1}' = A_{2}' \\))." + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.89, + 0.514, + 0.9 + ], + "angle": 0, + "content": "9046" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.113, + 0.126, + 0.345, + 0.14 + ], + "angle": 0, + "content": "The original intrinsics are \\(\\{f, u_0, v_0\\}\\)." + }, + { + "type": "text", + "bbox": [ + 0.112, + 0.141, + 0.473, + 0.281 + ], + "angle": 0, + "content": "Method1: transforming depth labels (CSTM_label). Fig. 3's ambiguity is for depths. Thus our first method directly transforms the ground-truth depth labels to solve this problem. Specifically, we scale the ground-truth depth \\((\\mathbf{D}^{*})\\) with the ratio \\(\\omega_{d} = \\frac{f^{c}}{f}\\) in training, i.e., \\(\\mathbf{D}_c^* = \\omega_d\\mathbf{D}^*\\). The original camera model is transformed to \\(\\{f^c,u_0,v_0\\}\\). In inference, the predicted depth \\((\\mathbf{D}_c)\\) is in the canonical space and needs to perform a de-canonical transformation to recover the metric information, i.e., \\(\\mathbf{D} = \\frac{1}{\\omega_d}\\mathbf{D}_c\\). Note the input \\(\\mathbf{I}\\) does not perform any transformation, i.e., \\(\\mathbf{I}_c = \\mathbf{I}\\)." + }, + { + "type": "text", + "bbox": [ + 0.112, + 0.282, + 0.473, + 0.436 + ], + "angle": 0, + "content": "Method2: transforming input images (CSTM_image). From another view, the ambiguity is caused by the similar image appearance. Thus this method is to transform the input image to simulate the canonical camera imaging effect. Specifically, the image \\(\\mathbf{I}\\) is resized with the ratio \\(\\omega_{r} = \\frac{f^{c}}{f}\\), i.e., \\(\\mathbf{I}_c = \\mathfrak{T}(\\mathbf{I},\\omega_r)\\), where \\(\\mathfrak{T}(\\cdot)\\) denotes image resize. The optical center is resized, thus the canonical camera model is \\(\\{f^c,\\omega_ru_0,\\omega_rv_0\\}\\). The ground-truth labels are resized without any scaling, i.e., \\(\\mathbf{D}_c^* = \\mathfrak{T}(\\mathbf{D}^*,\\omega_r)\\). In inference, the de-canonical transformation is to resize the prediction to the original size without scaling, i.e., \\(\\mathbf{D} = \\mathfrak{T}(\\mathbf{D}_c,\\frac{1}{\\omega_r})\\)" + }, + { + "type": "text", + "bbox": [ + 0.112, + 0.437, + 0.473, + 0.537 + ], + "angle": 0, + "content": "Fig. 2 shows the pipeline. After performing either transformation, we randomly crop a patch for training. The cropping only adjusts the FOV and the optical center, thus not causing any metric ambiguity issues. In the labels transformation method \\(\\omega_{r} = 1\\) and \\(\\omega_{d} = \\frac{f^{c}}{f}\\), while \\(\\omega_{d} = 1\\) and \\(\\omega_{r} = \\frac{f^{c}}{f}\\) in the images transformation method. The training objective is as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.225, + 0.55, + 0.472, + 0.57 + ], + "angle": 0, + "content": "\\[\n\\min _ {\\theta} \\left| \\mathfrak {N} _ {d} \\left(\\mathbf {I} _ {c}, \\theta\\right) - \\mathbf {D} _ {c} ^ {*} \\right| \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.112, + 0.576, + 0.473, + 0.604 + ], + "angle": 0, + "content": "where \\(\\theta\\) is the network's \\((\\mathcal{N}_d(\\cdot))\\) parameters, \\(\\mathbf{D}_c^*\\) and \\(\\mathbf{I}_c\\) are transformed ground-truth depth labels and images." + }, + { + "type": "text", + "bbox": [ + 0.112, + 0.605, + 0.473, + 0.785 + ], + "angle": 0, + "content": "Supervision. To further boost the performance, we propose a random proposal normalization loss (RPNL). The scale-shift invariant loss [32, 57] is widely applied for the affine-invariant depth estimation, which decouples the depth scale to emphasize the single image distribution. However, such normalization based on the whole image inevitably squeezes the fine-grained depth difference, particularly in close regions. Inspired by this, we propose to randomly crop several patches \\((p_{i(i = 0,\\dots,M)}\\in \\mathbb{R}^{h_i\\times w_i})\\) from the ground truth \\(\\mathbf{D}_c^*\\) and the predicted depth \\(\\mathbf{D}_c\\). Then we employ the median absolute deviation normalization [40] for paired patches. By normalizing the local statistics, we can enhance local contrast. The loss function is as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.117, + 0.795, + 0.472, + 0.871 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} L _ {\\mathrm {R P N L}} = \\frac {1}{M N} \\sum_ {p _ {i}} ^ {M} \\sum_ {j} ^ {N} \\left| \\frac {d _ {p _ {i} , j} ^ {*} - \\mu \\left(d _ {p _ {i} , j} ^ {*}\\right)}{\\frac {1}{N} \\sum_ {j} ^ {N} \\left| d _ {p _ {i} , j} ^ {*} - \\mu \\left(d _ {p _ {i} , j} ^ {*}\\right) \\right|} - \\right. \\\\ \\frac {d _ {p _ {i , j}} - \\mu \\left(d _ {p _ {i , j}}\\right)}{\\frac {1}{N} \\sum_ {j} ^ {N} \\left| d _ {p _ {i , j}} - \\mu \\left(d _ {p _ {i , j}}\\right) \\right|} \\tag {3} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.126, + 0.86, + 0.251 + ], + "angle": 0, + "content": "where \\(d^{*}\\in \\mathbf{D}_{c}^{*}\\) and \\(d\\in \\mathbf{D}_c\\) are the ground truth and predicted depth respectively. \\(\\mu (\\cdot)\\) and is the median of depth. \\(M\\) is the number of proposal crops, which is set to 32. During training, proposals are randomly cropped from the image by 0.125 to 0.5 of the original size. Furthermore, several other losses are employed, including the scale-invariant logarithmic loss [10] \\(L_{silog}\\), pair-wise normal regression loss [57] \\(L_{\\mathrm{PWN}}\\), virtual normal loss [53] \\(L_{\\mathrm{VNL}}\\). Note \\(L_{silog}\\) is a variant of L1 loss. The overall losses are as follows." + }, + { + "type": "equation", + "bbox": [ + 0.54, + 0.262, + 0.789, + 0.278 + ], + "angle": 0, + "content": "\\[\nL = L _ {\\mathrm {P W N}} + L _ {\\mathrm {V N L}} + L _ {\\text {s i l o g}} + L _ {\\mathrm {R P N L}}.\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.291, + 0.621, + 0.307 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.314, + 0.859, + 0.411 + ], + "angle": 0, + "content": "Dataset details. We collect 11 public RGB-D datasets, and over 8 million data for training. It spreads over diverse indoor and outdoor scenes. Note that all datasets have provided camera intrinsic parameters. Over 10K different cameras are included. Furthermore, we collect 7 unseen datasets for robustness and generalization evaluation. Details of employed data are reported in the supplementary materials." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.411, + 0.86, + 0.59 + ], + "angle": 0, + "content": "Implementation details. We use an UNet architecture with the ConvNext-large [26] backbone. ImageNet-22K pretrained weights are used for initialization. We use AdamW with a batch size of 192, an initial learning rate 0.0001 for all layers, and the polynomial decaying method with the power of 0.9. We use 48 A100 GPUs and train for 500K iterations. Following [53], we balance all datasets in a mini-batch to ensure each dataset accounts for an almost equal ratio. In training, images are processed by the LSTM, flipped horizontally with a \\(50\\%\\) chance, and then randomly cropped into \\(512 \\times 960\\). In ablation studies, training settings are different as we sample 5000 images from each dataset for training and train on 8 GPUs for 150K iterations." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.591, + 0.86, + 0.868 + ], + "angle": 0, + "content": "Evaluation details. a) To show the robustness of our metric depth estimation method, we test on 8 zero-shot benchmarks, including NYUv2 [39], KITTI [12], NuScenes [4], 7-scenes [38], iBIMS-1 [19], DIODE [45], ETH3D [37]. Absolute relative error (AbsRel), the accuracy under threshold \\((\\delta_i < 1.25^i, i = 1,2,3)\\), root mean squared error (RMS), root mean squared error in log space (RMS_log), and log10 error (log10) metrics are employed. b) Furthermore, we also follow current affine-invariant depth benchmarks [57, 60] (Tab. 4) to evaluate the generalization ability on 5 zero-shot datasets, i.e., NYUv2, DIODE, ETH3D, ScanNet [7], and KITTI. We mainly compare with large-scale data trained models. Note that in this benchmark we follow existing methods to apply the scale shift alignment before evaluation. c) To evaluate our metric 3D reconstruction quality, we randomly sample 9 unseen scenes from NYUv2 and use colmap [36] to obtain the camera poses for multi-frame reconstruction. Chamfer \\(l_{1}\\) distance and the F-score [18] are used to evaluate the reconstruction accuracy. d) In dense-SLAM experiments, following Li et al. [24], we" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.89, + 0.514, + 0.9 + ], + "angle": 0, + "content": "9047" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.119, + 0.124, + 0.468, + 0.157 + ], + "angle": 0, + "content": "Table 1 - Quantitative comparison on NYUv2 and KITTI benchmarks. Both datasets are unseen to our model, but we can achieve comparable performance with state-of-the-art methods." + }, + { + "type": "table", + "bbox": [ + 0.118, + 0.158, + 0.474, + 0.344 + ], + "angle": 0, + "content": "
NYUv2 Benchmark
Methodδ1↑δ2↑δ3↑AbsRel↓log10↓RMS↓
Li et al. [23]0.7880.9580.9910.1430.0630.635
Laina et al. [21]0.8110.9530.9880.1270.0550.573
VNL [55]0.8750.9760.9940.1080.0480.416
TrDepth [52]0.9000.9830.9960.1060.0450.365
Adabins [2]0.9030.9840.9970.1030.0440.364
NeWCRFs [59]0.9220.9920.9980.0950.0410.334
Ours LSTM_image0.9250.9830.9940.0920.0400.341
Ours LSTM_label0.9440.9860.9950.0830.0350.310
KITTI Benchmark
Methodδ1↑δ2↑δ3↑AbsRel↓RMS↓RMS_log↓
Guo et al. [14]0.9020.9690.9860.0903.2580.168
VNL [55]0.9380.9900.9980.0723.2580.117
TrDepth [52]0.9560.9940.9990.0642.7550.098
Adabins [2]0.9640.9950.9990.0582.3600.088
NeWCRFs [59]0.9740.9970.9990.0522.1290.079
Ours LSTM_image0.9670.9950.9990.0602.8430.087
Ours LSTM_label0.9640.9930.9980.0582.7700.092
" + }, + { + "type": "text", + "bbox": [ + 0.113, + 0.359, + 0.473, + 0.402 + ], + "angle": 0, + "content": "test on the KITTI odometry benchmark [12] and evaluate the average translational RMS drift \\((\\% ,t_{rel})\\) and rotational RMS drift \\((^{\\circ} / 100m,r_{rel})\\) errors [12]." + }, + { + "type": "title", + "bbox": [ + 0.114, + 0.427, + 0.356, + 0.44 + ], + "angle": 0, + "content": "4.1. Zero-shot Generalization Test" + }, + { + "type": "text", + "bbox": [ + 0.112, + 0.454, + 0.473, + 0.566 + ], + "angle": 0, + "content": "Evaluation on metric depth benchmarks. To evaluate the accuracy of predicted metric depth, firstly, we compare with state-of-the-art (SOTA) metric depth prediction methods on NYUv2 [39], KITTI [13]. We use the same model to do all evaluations. Results are reported in Tab. 1. Without any fine-tuning or metric adjustment, we can achieve comparable performance with SOTA methods, which are trained on benchmarks for hundreds of epochs." + }, + { + "type": "text", + "bbox": [ + 0.112, + 0.571, + 0.472, + 0.722 + ], + "angle": 0, + "content": "Furthermore, we collect 6 unseen datasets to do more metric accuracy evaluation. These datasets contain a wide range of indoor and outdoor scenes. The camera models are also various, e.g. 7scenes has a short focal length (around 500), while ETH3D is 2000. We compare with the SOTA metric depth estimation methods and take their NYUv2 and KITTI models for indoor and outdoor scenes evaluation respectively. In Tab. 3, although 7Scenes is similar to NYUv2 and NuScenes is similar to KITTI, existing methods face a noticeable performance decrease. In contrast, our model is more robust." + }, + { + "type": "text", + "bbox": [ + 0.112, + 0.729, + 0.473, + 0.867 + ], + "angle": 0, + "content": "Generalization over diverse scenes. Affine-invariant depth benchmarks decouple the scale's effect, which aims to evaluate the model's generalization ability to diverse scenes. Recent impact works, such as MiDaS, LeReS, and DPT, achieved promising performance on them. Following them, we test on 5 datasets and manually align the scale and shift to the ground-truth depth before evaluation. Results are reported in Tab. 4. Although our method enforces the network to recover more challenging metric information, our method outperforms them by a large margin on most datasets." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.126, + 0.782, + 0.14 + ], + "angle": 0, + "content": "4.2. Applications Based on Our Method" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.147, + 0.86, + 0.41 + ], + "angle": 0, + "content": "3D scene reconstruction. To demonstrate our work can recover the 3D metric shape in the wild, we first do the quantitative comparison on 9 NYUv2 scenes, which are unseen during training. We predict the per-frame metric depth and then fuse them together with provided camera poses. Results are reported in Tab. 2. We compare with the video consistent depth prediction method (RCVD [20]), the unsupervised video depth estimation method (SC-DepthV2 [3]), the 3D scene shape recovery method (LeReS [57]), affine-invariant depth estimation method (DPT [31]), and the multi-view stereo reconstruction method (DPSNet [17]). Apart from DPSNet and our method, other methods have to align the scale with the ground truth depth for each frame. Although our method does not aim for the video or multi-view reconstruction problem, our method can achieve promising consistency between frames and reconstruct much more accurate 3D scenes than others on these zero-shot scenes. From the qualitative comparison in Fig. 6, our reconstructions have much less noise and outliers." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.41, + 0.86, + 0.645 + ], + "angle": 0, + "content": "Dense-SLAM mapping. Monocular SLAM is an important robotics application. It takes a monocular video input to create the trajectory and dense 3D mapping. Owing to limited photometric and geometric constraints, existing methods face serious scale drift problems in large scenes and cannot recover the metric information. Our robust metric depth estimation method is a strong depth prior to the SLAM system. To demonstrate this benefit, we naively input our metric depth to the SOTA SLAM system, Droid-SLAM [44], and evaluate the trajectory on KITTI. We do not do any tuning on the original system. Trajectory comparisons are reported in Tab. 5. As Droid-SLAM can access accurate per-frame metric depth, like an RGB-D SLAM, the translation drift \\((t_{rel})\\) decreases significantly. Furthermore, with our depths, Droid-SLAM can perform denser and more accurate 3D mapping. An example is shown in Fig. 1 and more cases are shown in the supplementary materials." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.645, + 0.86, + 0.756 + ], + "angle": 0, + "content": "Metrology in the wild. To show the robustness and accuracy of our recovered metric 3D, we download Flickr photos captured by various cameras and collect coarse camera intrinsic parameters from their metadata. We use our CSTM_image model to reconstruct their metric shape and measure structures' sizes (marked in red in Fig. 7), while the ground-truth sizes are in blue. It shows that our measured sizes are very close to the ground-truth sizes." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.763, + 0.64, + 0.778 + ], + "angle": 0, + "content": "4.3. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.784, + 0.86, + 0.868 + ], + "angle": 0, + "content": "Ablation on canonical transformation. We study the effect of our proposed canonical transformation for the input images ('CSTM_input') and the canonical transformation for the ground-truth labels ('CSTM_output'). Results are reported in Tab. 6. We train the model on sampled mixed data (55K images) and test it on 6 datasets. A naive base" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.89, + 0.514, + 0.9 + ], + "angle": 0, + "content": "9048" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.119, + 0.124, + 0.854, + 0.157 + ], + "angle": 0, + "content": "Table 2 - Quantitative comparison of 3D scene reconstruction with LeReS [57], DPT [31], RCVD [20], SC-DepthV2 [3], and a learning-based MVS method (DPSNet [17]) on 9 unseen NYUv2 scenes. Apart from DPSNet and ours, other methods have to align the scale with ground truth depth for each frame. As a result, our reconstructed 3D scenes achieve the best performance." + }, + { + "type": "table", + "bbox": [ + 0.12, + 0.158, + 0.85, + 0.251 + ], + "angle": 0, + "content": "
MethodBasement_0001aBedroom_0015Dining_room_0004Kitchen_0008Classroom_0004Playroom_0002Office_0024Office_0004Dining_room_0033
C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑
RCVD [20]0.3640.2760.0740.5820.4620.2510.0530.6200.1870.3270.7910.1870.3240.2410.6460.2170.4450.253
SC-DepthV2 [3]0.2540.2750.0640.5470.7490.2290.0490.6240.1670.2670.4260.2630.4820.1380.5160.2440.3560.247
DPSNet [17]0.2430.2990.1950.2760.9950.1860.2690.2030.2960.1950.1410.4850.1990.3620.2100.4620.2220.493
DPT [57]0.6980.2510.2890.2260.3960.3640.1260.3880.7800.1930.6050.2690.4540.2450.3640.2790.7510.185
LeReS [57]0.0810.5550.0640.6160.2780.4270.1470.2890.1430.4800.1450.5030.4080.1760.0960.4970.2410.325
Ours0.0420.7360.0590.6100.1590.4850.0500.6450.1450.4450.0360.8140.0690.6380.0450.7000.0600.663
" + }, + { + "type": "image", + "bbox": [ + 0.144, + 0.263, + 0.825, + 0.342 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.144, + 0.342, + 0.825, + 0.414 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.144, + 0.414, + 0.825, + 0.49 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.144, + 0.49, + 0.825, + 0.564 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.119, + 0.564, + 0.854, + 0.598 + ], + "angle": 0, + "content": "Figure 6 - Reconstruction of zero-shot scenes with multiple views. We sample several NYUv2 scenes for 3D reconstruction comparison. As our method can predict accurate metric depth, thus all predictions are fused together for scene reconstruction. By contrast, LeReS [57]'s depth is up to an unknown scale and shift, which causes noticeable distortions. DPSNet [17] is a multi-view stereo method, which cannot work well on low-texture regions." + }, + { + "type": "image", + "bbox": [ + 0.116, + 0.609, + 0.487, + 0.794 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.119, + 0.797, + 0.466, + 0.842 + ], + "angle": 0, + "content": "Figure 7 - Reconstruction of in-the-wild scenes. We collect several Flickr photos, which are captured by various cameras. With photos' metadata, we reconstruct the 3D metric shape and measure structures' sizes. Red and blue marks are ours and ground-truth sizes respectively." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.61, + 0.86, + 0.859 + ], + "angle": 0, + "content": "line ('Ours w/o LSTM') is to remove LSTM modules and enforce the same supervision as ours. Without LSTM, the model is unable to converge when training on mixed metric datasets and lost the metric prediction ability on zero-shot datasets. This is why mixed-data training methods compromise learning the affine-invariant depth to avoid metric issues. In contrast, our LSTM methods can enable the model to achieve the metric prediction ability, and they can achieve comparable performance. Tab. 1 also shows comparable performance. Therefore, both adjusting the supervision and the input image appearance during training can solve the metric ambiguity issues. Furthermore, we compare with CamConvs [11], which encodes the camera model in the decoder with a 4-channel feature. It employs the same training schedule, model, and training data as ours. This method enforces the network to implicitly understand various camera models from the image appearance and then bridges the imaging size to the real-world size. We believe that this" + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.89, + 0.514, + 0.9 + ], + "angle": 0, + "content": "9049" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.12, + 0.124, + 0.854, + 0.146 + ], + "angle": 0, + "content": "Table 3 - Quantitative comparison with SOTA metric depth methods on 6 unseen benchmarks. For SOTA methods, we use their NYUv2 and KITTI models for indoor and outdoor scenes evaluation respectively, while we use the same model for all zero-shot testing." + }, + { + "type": "table", + "bbox": [ + 0.166, + 0.147, + 0.803, + 0.221 + ], + "angle": 0, + "content": "
MethodDIODE(Indoor) Indoor scenes (AbsRel↓/RMS↓)DIODE(Outdoor) Outdoor scenes (AbsRel↓/RMS↓)
Adabins [2]0.443 / 1.9630.212 / 0.9010.218 / 0.4280.865 / 10.351.271 / 6.1780.445 / 10.658
NewCRFs [59]0.404 / 1.8670.206 / 0.8610.240 / 0.4510.854 / 9.2280.890 / 5.0110.400 / 12.139
Ours_CSTM_label0.252 / 1.4400.160 / 0.5210.183 / 0.3630.414 / 6.9340.416 / 3.0170.154 / 7.097
Ours_CSTM_image0.268 / 1.4290.144 / 0.6460.189 / 0.3880.535 / 6.5070.342 / 2.9650.147 / 5.889
" + }, + { + "type": "table_caption", + "bbox": [ + 0.12, + 0.224, + 0.854, + 0.247 + ], + "angle": 0, + "content": "Table 4 - Comparison with SOTA affine-invariant depth methods on 5 zero-shot transfer benchmarks. Our model significantly outperforms previous methods and sets new state-of-the-art. Following the benchmark setting, all methods have manually aligned the scale and shift." + }, + { + "type": "table", + "bbox": [ + 0.17, + 0.248, + 0.803, + 0.357 + ], + "angle": 0, + "content": "
MethodBackbone#ParamsNYUv2KITTIDIODEScanNetETH3DRank
AbsRel↓δ1↑AbsRel↓δ1↑AbsRel↓δ1↑AbsRel↓δ1↑AbsRel↓δ1↑
DiverseDepth [53]ResNeXt50 [50]25M0.1170.8750.1900.7040.3760.6310.1080.8820.2280.6947.7
MiDaS [32]ResNeXt10188M0.1110.8850.2360.6300.3320.7150.1110.8860.1840.7527.2
Leres [57]ResNeXt1010.0900.9160.1490.7840.2710.7660.0950.9120.1710.7775.4
Omnidata [9]ViT-base0.0740.9450.1490.8350.3390.7420.0770.9350.1660.7784.9
HDN [60]ViT-Large [8]306M0.0690.9480.1150.8670.2460.7800.0800.9390.1210.8333.7
DPT-large [31]ViT-Large0.0980.9030.100.9010.1820.7580.0780.9380.0780.9463.8
Ours LSTM_imageConvNeXt-large [26]198M0.0580.9630.0530.9650.2110.8250.0740.9420.0640.9651.3
Ours LSTM_labelConvNeXt-large0.0500.9660.0580.9700.2240.8050.0740.9410.0660.9641.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.119, + 0.363, + 0.466, + 0.396 + ], + "angle": 0, + "content": "Table 5 - Comparison with SOTA SLAM methods on KITTI. We input predicted metric depth to the Droid-SLAM [44] ('Droid+Ours'), which outperforms others by a large margin on trajectory accuracy." + }, + { + "type": "table", + "bbox": [ + 0.116, + 0.397, + 0.468, + 0.469 + ], + "angle": 0, + "content": "
MethodSeq 00Seq 02Seq 05Seq 06Seq 08Seq 09Seq 10
Translational RMS drift (frel, ↓) / Rotational RMS drift (rrel, ↓)
GeoNet [58]27.6/5.7242.24/6.1420.12/7.679.28/4.3418.59/7.8523.94/9.8120.73/9.1
VISO2-M [41]12.66/2.739.47/1.1915.1/3.656.8/1.9314.82/2.523.69/1.2521.01/3.26
ORB-V2 [28]11.43/0.5810.34/0.269.04/0.2614.56/0.2611.46/0.289.3/0.262.57/0.32
Droid [44]33.9/0.2934.88/0.2723.4/0.2717.2/0.2639.6/0.3121.7/0.237/0.25
Droid+Ours1.44/0.372.64/0.291.44/0.250.6/0.22.2/0.31.63/0.222.73/0.23
" + }, + { + "type": "table_caption", + "bbox": [ + 0.119, + 0.483, + 0.466, + 0.527 + ], + "angle": 0, + "content": "Table 6 - Effectiveness of our LSTM. CamConvs [11] directly encodes various camera models in the network, while we perform a simple yet effective transformation to solve the metric ambiguity. Without LSTM, the model cannot achieve transferable metric prediction ability." + }, + { + "type": "table", + "bbox": [ + 0.117, + 0.528, + 0.466, + 0.587 + ], + "angle": 0, + "content": "
MethodDDAD Test set of train.Lyft data (AbsRel↓)DSNS Zero-shot test setKITTI (AbsRel↓)NYU
w/o LSTM0.5300.5820.3941.000.5680.584
CamConvs [11]0.2950.3150.2130.4230.1780.333
Ours CSTM_image0.1900.2350.1820.1970.0970.210
Ours CSTM_label0.1830.2210.2010.2130.0810.212
" + }, + { + "type": "text", + "bbox": [ + 0.113, + 0.603, + 0.471, + 0.629 + ], + "angle": 0, + "content": "method challenges the data diversity and network capacity, thus our performance is better than theirs." + }, + { + "type": "text", + "bbox": [ + 0.113, + 0.631, + 0.472, + 0.755 + ], + "angle": 0, + "content": "Ablation on canonical space. We study the effect of the canonical camera here, i.e., the canonical focal length. We train the model on the small sampled dataset and test it on the validation set and testing data. The average AbsRel error is calculated. We experiment on 3 different focal lengths, i.e., 500, 1000, 1500. Experiments show that \\( \\text{focal} = 1000 \\) has slightly better performance than others, see Fig. 8. Thus we set the canonical focal length to 1000 in our experiments." + }, + { + "type": "text", + "bbox": [ + 0.113, + 0.757, + 0.473, + 0.867 + ], + "angle": 0, + "content": "Effectiveness of the random proposal normalization loss. To show the effectiveness of our proposed random proposal normalization loss (RPNL), we experiment on the sampled small dataset. Results are shown in Tab. 7. We test on the DDAD, Lyft, DrivingStereo (DS), NuScenes (NS), KITTI, and NYUv2. The 'baseline' employs all losses except our RPNL. We compare it with 'baseline + RPNL' and 'baseline + SSIL [32]'. We can observe that our proposed" + }, + { + "type": "image", + "bbox": [ + 0.566, + 0.361, + 0.793, + 0.445 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.505, + 0.454, + 0.854, + 0.488 + ], + "angle": 0, + "content": "Figure 8 - Effect of different canonical focal lengths. We experiment on different canonical focal lengths and find that too large or small focal lengths will impact the performance." + }, + { + "type": "table_caption", + "bbox": [ + 0.505, + 0.491, + 0.854, + 0.524 + ], + "angle": 0, + "content": "Table 7 - Effectiveness of random proposal normalization loss. Baseline is supervised by \\( L_{\\mathrm{PWN}} + L_{\\mathrm{VNL}} + L_{\\mathrm{silog}} \\). SSL is the scale-shift invariant loss proposed in [32]." + }, + { + "type": "table", + "bbox": [ + 0.504, + 0.525, + 0.857, + 0.575 + ], + "angle": 0, + "content": "
MethodDDAD Test set of train.Lyft data (AbsRel↓)DSNS Zero-shot test setKITTI (AbsRel↓)NYUv2
baseline0.2040.2510.1840.2070.1040.230
baseline + SSL [32]0.1970.2630.2590.2060.1050.216
baseline + RPNL0.1900.2350.1820.1970.0970.210
" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.579, + 0.859, + 0.635 + ], + "angle": 0, + "content": "random proposal normalization loss can further improve the performance. In contrast, the scale-shift invariant loss [32], which does the normalization on the whole image, can only slightly improve the performance." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.649, + 0.609, + 0.663 + ], + "angle": 0, + "content": "5. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.673, + 0.86, + 0.824 + ], + "angle": 0, + "content": "In this paper, we tackle the problem of reconstructing the 3D metric scene from a single monocular image. To solve the depth ambiguity in image appearance caused by various focal lengths, we propose a canonical camera space transformation method. With our method, we can easily merge millions of data captured by 10k cameras to train one metric depth model. To improve the robustness, we collected over 8M data for training. Several zero-shot evaluations show the effectiveness and robustness of our work. We further show the ability to do metrology on randomly collected internet images and dense mapping on large-scale scenes." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.826, + 0.859, + 0.867 + ], + "angle": 0, + "content": "Acknowledgements This work was in part supported by National Key R&D Program of China (No. 2022ZD0118700)." + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.89, + 0.514, + 0.9 + ], + "angle": 0, + "content": "9050" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.115, + 0.125, + 0.201, + 0.139 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.122, + 0.148, + 0.473, + 0.186 + ], + "angle": 0, + "content": "[1] Jonathan T Barron and Jitendra Malik. Shape, illumination, and reflectance from shading. IEEE Trans. Pattern Anal. Mach. Intell., 37(8):1670-1687, 2014. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.122, + 0.187, + 0.472, + 0.237 + ], + "angle": 0, + "content": "[2] Shariq Farooq Bhat, Ibrahim Alhashim, and Peter Wonka. Adabins: Depth estimation using adaptive bins. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 4009-4018, 2021. 2, 3, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.122, + 0.239, + 0.473, + 0.288 + ], + "angle": 0, + "content": "[3] Jia-Wang Bian, Huangying Zhan, Naiyan Wang, Tat-Jin Chin, Chunhua Shen, and Ian Reid. Auto-rectify network for unsupervised indoor depth estimation. IEEE Trans. Pattern Anal. Mach. Intell., 2021. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.122, + 0.29, + 0.472, + 0.354 + ], + "angle": 0, + "content": "[4] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 11621-11631, 2020. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.122, + 0.355, + 0.472, + 0.392 + ], + "angle": 0, + "content": "[5] Weifeng Chen, Zhao Fu, Dawei Yang, and Jia Deng. Single-image depth perception in the wild. In Proc. Advances in Neural Inf. Process. Syst., pages 730-738, 2016. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.122, + 0.393, + 0.472, + 0.443 + ], + "angle": 0, + "content": "[6] Weifeng Chen, Shengyi Qian, David Fan, Noriyuki Kojima, Max Hamilton, and Jia Deng. Oasis: A large-scale dataset for single image 3d in the wild. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 679-688, 2020. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.122, + 0.445, + 0.473, + 0.507 + ], + "angle": 0, + "content": "[7] Angela Dai, Angel X Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 5828-5839, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.122, + 0.508, + 0.472, + 0.584 + ], + "angle": 0, + "content": "[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. Proc. Int. Conf. Learn. Representations, 2021. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.122, + 0.585, + 0.472, + 0.635 + ], + "angle": 0, + "content": "[9] Ainaz Eftekhar, Alexander Sax, Jitendra Malik, and Amir Zamir. Omnidata: A scalable pipeline for making multi-task mid-level vision datasets from 3d scans. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 10786-10796, 2021. 3, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.115, + 0.636, + 0.472, + 0.686 + ], + "angle": 0, + "content": "[10] David Eigen, Christian Puhrsch, and Rob Fergus. Depth map prediction from a single image using a multi-scale deep network. In Proc. Advances in Neural Inf. Process. Syst., pages 2366-2374, 2014. 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.115, + 0.688, + 0.472, + 0.751 + ], + "angle": 0, + "content": "[11] Jose Facil, Benjamin Ummenhofer, Huizhong Zhou, Luis Montesano, Thomas Brox, and Javier Civera. CAM-Convs: camera-aware multi-scale convolutions for single-view depth. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 11826-11835, 2019. 2, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.115, + 0.752, + 0.472, + 0.789 + ], + "angle": 0, + "content": "[12] Andreas Geiger, Philip Lenz, Christoph Stiller, and Raquel Urtasun. Vision meets robotics: The kitti dataset. Int. J. Robot. Res., 2013. 3, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.115, + 0.79, + 0.472, + 0.84 + ], + "angle": 0, + "content": "[13] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the kitti vision benchmark suite. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 3354-3361. IEEE, 2012. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.115, + 0.841, + 0.472, + 0.868 + ], + "angle": 0, + "content": "[14] Xiaoyang Guo, Hongsheng Li, Shuai Yi, Jimmy Ren, and Xiaogang Wang. Learning monocular depth by distilling" + }, + { + "type": "list", + "bbox": [ + 0.115, + 0.148, + 0.473, + 0.868 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.533, + 0.128, + 0.857, + 0.153 + ], + "angle": 0, + "content": "cross-domain stereo networks. In Proc. Eur. Conf. Comp. Vis., pages 484-500, 2018. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.155, + 0.857, + 0.19 + ], + "angle": 0, + "content": "[15] Richard Hartley and Andrew Zisserman. Multiple view geometry in computer vision. Cambridge university press, 2003. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.193, + 0.857, + 0.257 + ], + "angle": 0, + "content": "[16] Yannick Hold-Geoffroy, Kalyan Sunkavalli, Jonathan Eisenmann, Matthew Fisher, Emiliano Gambaretto, Sunil Hadap, and Jean-François Lalonde. A perceptual measure for deep single image camera calibration. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2354-2363, 2018. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.258, + 0.857, + 0.296 + ], + "angle": 0, + "content": "[17] Sunghoon Im, Hae-Gon Jeon, Stephen Lin, and In-So Kweon. Dpsnet: End-to-end deep plane sweep stereo. In Proc. Int. Conf. Learn. Representations, 2019. 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.297, + 0.857, + 0.335 + ], + "angle": 0, + "content": "[18] Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: Benchmarking large-scale scene reconstruction. ACM Trans. Graph., 36(4):1-13, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.336, + 0.857, + 0.386 + ], + "angle": 0, + "content": "[19] Tobias Koch, Lukas Liebel, Friedrich Fraundorfer, and Marco Korner. Evaluation of cnn-based single-image depth estimation methods. In *Eur. Conf. Comput. Vis. Worksh.*, pages 0–0, 2018. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.388, + 0.857, + 0.426 + ], + "angle": 0, + "content": "[20] Johannes Kopf, Xuejian Rong, and Jia-Bin Huang. Robust consistent video depth estimation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2021. 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.427, + 0.857, + 0.49 + ], + "angle": 0, + "content": "[21] Iro Laina, Christian Rupprecht, Vasileios Belagiannis, Federico Tombari, and Nassir Navab. Deeper depth prediction with fully convolutional residual networks. In 2016 Fourth international conference on 3D vision (3DV), pages 239-248. IEEE, 2016. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.491, + 0.857, + 0.542 + ], + "angle": 0, + "content": "[22] John Lambert, Zhuang Liu, Ozan Sener, James Hays, and Vladlen Koltun. Mseg: A composite dataset for multi-domain semantic segmentation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2879-2888, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.543, + 0.857, + 0.594 + ], + "angle": 0, + "content": "[23] Jun Li, Reinhard Klein, and Angela Yao. A two-streamed network for estimating fine-scaled depth maps from singlergb images. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 3372-3380, 2017. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.595, + 0.857, + 0.646 + ], + "angle": 0, + "content": "[24] Shunkai Li, Xin Wu, Yingdian Cao, and Hongbin Zha. Generalizing to the open world: Deep visual odometry with online adaptation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 13184-13193, 2021. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.647, + 0.857, + 0.696 + ], + "angle": 0, + "content": "[25] Yifan Liu, Hao Chen, Yu Chen, Wei Yin, and Chunhua Shen. Generic perceptual loss for modeling structured output dependencies. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.698, + 0.857, + 0.749 + ], + "angle": 0, + "content": "[26] Zhuang Liu, Hanzi Mao, Chao-Yuan Wu, Christoph Feichtenhofer, Trevor Darrell, and Saining Xie. A convnet for the 2020s. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 11976-11986, 2022. 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.75, + 0.857, + 0.8 + ], + "angle": 0, + "content": "[27] Raul Mur-Artal and Juan D Tardós. Orb-slam2: An open-source slam system for monocular, stereo, and rgb-d cameras. IEEE transactions on robotics, 33(5):1255-1262, 2017. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.802, + 0.857, + 0.84 + ], + "angle": 0, + "content": "[28] Raul Mur-Artal and Juan D. Tardós. ORB-SLAM2: an open-source SLAM system for monocular, stereo and RGB-D cameras. IEEE Trans. Robot., 33(5):1255-1262, 2017. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.841, + 0.857, + 0.867 + ], + "angle": 0, + "content": "[29] Sida Peng, Shangzhan Zhang, Zhen Xu, Chen Geng, Boyi Jiang, Hujun Bao, and Xiaowei Zhou. Animatable neural" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.128, + 0.857, + 0.867 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.89, + 0.513, + 0.9 + ], + "angle": 0, + "content": "9051" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.145, + 0.128, + 0.471, + 0.153 + ], + "angle": 0, + "content": "implicit surfaces for creating avatars from videos. arXiv: Comp. Res. Repository, page 2203.08133, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.155, + 0.472, + 0.229 + ], + "angle": 0, + "content": "[30] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In Proc. Int. Conf. Mach. Learn., pages 8748-8763. PMLR, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.232, + 0.472, + 0.269 + ], + "angle": 0, + "content": "[31] René Ranftl, Alexey Bochkovskiy, and Vladlen Koltun. Vision transformers for dense prediction. In Proc. IEEE Int. Conf. Comp. Vis., pages 12179-12188, 2021. 2, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.271, + 0.472, + 0.333 + ], + "angle": 0, + "content": "[32] René Ranftl, Katrin Lasinger, David Hafner, Konrad Schindler, and Vladlen Koltun. Towards robust monocular depth estimation: Mixing datasets for zero-shot cross-dataset transfer. IEEE Trans. Pattern Anal. Mach. Intell., 2020. 2, 3, 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.335, + 0.472, + 0.398 + ], + "angle": 0, + "content": "[33] Shunsuke Saito, Zeng Huang, Ryota Natsume, Shigeo Morishima, Angjoo Kanazawa, and Hao Li. Pifu: Pixel-aligned implicit function for high-resolution clothed human digitization. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2304-2314, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.401, + 0.472, + 0.451 + ], + "angle": 0, + "content": "[34] Shunsuke Saito, Tomas Simon, Jason Saragih, and Hanbyul Joo. Pifuhd: Multi-level pixel-aligned implicit function for high-resolution 3d human digitization. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 84-93, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.453, + 0.472, + 0.49 + ], + "angle": 0, + "content": "[35] Ashutosh Saxena, Min Sun, and Andrew Y Ng. Make3d: Learning 3d scene structure from a single still image. IEEE Trans. Pattern Anal. Mach. Intell., 31(5):824-840, 2008. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.492, + 0.472, + 0.541 + ], + "angle": 0, + "content": "[36] Johannes Lutz Schonberger, Enliang Zheng, Marc Pollefeys, and Jan-Michael Frahm. Pixelwise view selection for unstructured multi-view stereo. In Proc. Eur. Conf. Comp. Vis., 2016. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.544, + 0.472, + 0.607 + ], + "angle": 0, + "content": "[37] Thomas Schops, Johannes L Schonberger, Silvano Galliani, Torsten Sattler, Konrad Schindler, Marc Pollefeys, and Andreas Geiger. A multi-view stereo benchmark with high-resolution images and multi-camera videos. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 3260-3269, 2017. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.609, + 0.472, + 0.671 + ], + "angle": 0, + "content": "[38] Jamie Shotton, Ben Glocker, Christopher Zach, Shahram Izadi, Antonio Criminisi, and Andrew Fitzgibbon. Scene coordinate regression forests for camera relocalization in rgb-d images. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2930-2937, 2013. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.673, + 0.472, + 0.723 + ], + "angle": 0, + "content": "[39] Nathan Silberman, Derek Hoiem, Pushmeet Kohli, and Rob Fergus. Indoor segmentation and support inference from rgbd images. In Proc. Eur. Conf. Comp. Vis., pages 746-760. Springer, 2012. 3, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.726, + 0.472, + 0.763 + ], + "angle": 0, + "content": "[40] Dalwinder Singh and Birmohan Singh. Investigating the impact of data normalization on classification performance. Applied Soft Computing, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.765, + 0.472, + 0.814 + ], + "angle": 0, + "content": "[41] Shiyu Song, Manmohan Chandraker, and Clark C Guest. High accuracy monocular sfm and scale correction for autonomous driving. IEEE Trans. Pattern Anal. Mach. Intell., 38(4):730-743, 2015. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.817, + 0.472, + 0.867 + ], + "angle": 0, + "content": "[42] Jaime Spencer, C. Stella Qian, Michaela Trescakova, Chris Russell, Simon Hadfield, Erich W. Graf, Wendy J. Adams, Andrew J. Schofield, James Elder, Richard Bowden, Ali Anwar, Hao Chen, Xiaozhi Chen, Kai Cheng, Yuchao Dai," + }, + { + "type": "list", + "bbox": [ + 0.117, + 0.128, + 0.472, + 0.867 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.532, + 0.128, + 0.858, + 0.253 + ], + "angle": 0, + "content": "Huynh Thai Hoa, Sadat Hossain, Jianmian Huang, Mohan Jing, Bo Li, Chao Li, Baojun Li, Zhiwen Liu, Stefano Mattoccia, Siegfried Mercelis, Myungwoo Nam, Matteo Poggi, Xiaohua Qi, Jiahui Ren, Yang Tang, Fabio Tosi, Linh Trinh, S. M. Nadim Uddin, Khan Muhammad Umair, Kaixuan Wang, Yufei Wang, Yixing Wang, Mochu Xiang, Guangkai Xu, Wei Yin, Jun Yu, Qi Zhang, and Chaoqiang Zhao. The second monocular depth estimation challenge. In IEEE Conf. Comput. Vis. Pattern Recog. Worksh., pages 3063-3075, June 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.256, + 0.858, + 0.305 + ], + "angle": 0, + "content": "[43] Libo Sun, Wei Yin, Enze Xie, Zhengrong Li, Changming Sun, and Chunhua Shen. Improving monocular visual odometry using learned depth. IEEE Transactions on Robotics, 38(5):3173-3186, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.308, + 0.858, + 0.345 + ], + "angle": 0, + "content": "[44] Zachary Teed and Jia Deng. Droid-slam: Deep visual slam for monocular, stereo, and rgb-d cameras. volume 34, pages 16558-16569, 2021. 1, 3, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.348, + 0.858, + 0.411 + ], + "angle": 0, + "content": "[45] Igor Vasiljevic, Nick Kolkin, Shanyi Zhang, Ruotian Luo, Haochen Wang, Falcon Z Dai, Andrea F Daniele, Mohammadreza Mostajabi, Steven Basart, Matthew R Walter, et al. Diode: A dense indoor and outdoor depth dataset. arXiv: Comp. Res. Repository, page 1908.00463, 2019. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.413, + 0.858, + 0.462 + ], + "angle": 0, + "content": "[46] Nanyang Wang, Yinda Zhang, Zhuwen Li, Yanwei Fu, Wei Liu, and Yu-Gang Jiang. Pixel2mesh: Generating 3d mesh models from single RGB images. In Proc. Eur. Conf. Comp. Vis., pages 52-67, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.464, + 0.858, + 0.526 + ], + "angle": 0, + "content": "[47] Jiajun Wu, Chengkai Zhang, Xiuming Zhang, Zhoutong Zhang, William Freeman, and Joshua Tenenbaum. Learning shape priors for single-view 3d completion and reconstruction. In Proc. Eur. Conf. Comp. Vis., pages 646-662, 2018. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.529, + 0.858, + 0.579 + ], + "angle": 0, + "content": "[48] Ke Xian, Chunhua Shen, Zhiguo Cao, Hao Lu, Yang Xiao, Ruibo Li, and Zhenbo Luo. Monocular relative depth perception with web stereo data supervision. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 311-320, 2018. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.581, + 0.858, + 0.631 + ], + "angle": 0, + "content": "[49] Ke Xian, Jianming Zhang, Oliver Wang, Long Mai, Zhe Lin, and Zhiguo Cao. Structure-guided ranking loss for single image depth prediction. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 611-620, 2020. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.633, + 0.858, + 0.683 + ], + "angle": 0, + "content": "[50] Saining Xie, Ross Girshick, Piotr Dólar, Zhuowen Tu, and Kaiming He. Aggregated residual transformations for deep neural networks. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 1492-1500, 2017. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.686, + 0.858, + 0.735 + ], + "angle": 0, + "content": "[51] Guangkai Xu, Wei Yin, Hao Chen, Chunhua Shen, Kai Cheng, and Feng Zhao. Pose-free 3d scene reconstruction with frozen depth models. In Proc. IEEE Int. Conf. Comp. Vis., 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.738, + 0.858, + 0.787 + ], + "angle": 0, + "content": "[52] Guanglei Yang, Hao Tang, Mingli Ding, Nicu Sebe, and Elisa Ricci. Transformer-based attention networks for continuous pixel-wise prediction. In Proc. IEEE Int. Conf. Comp. Vis., 2021. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.79, + 0.858, + 0.838 + ], + "angle": 0, + "content": "[53] Wei Yin, Yifan Liu, and Chunhua Shen. Virtual normal: Enforcing geometric constraints for accurate and robust depth prediction. IEEE Trans. Pattern Anal. Mach. Intell., 2021. 2, 3, 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.842, + 0.858, + 0.867 + ], + "angle": 0, + "content": "[54] Wei Yin, Yifan Liu, Chunhua Shen, Anton van den Hengel, and Baichuan Sun. The devil is in the labels: Semantic seg" + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.128, + 0.858, + 0.867 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.89, + 0.514, + 0.9 + ], + "angle": 0, + "content": "9052" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.145, + 0.128, + 0.472, + 0.153 + ], + "angle": 0, + "content": "mentation from sentences. arXiv: Comp. Res. Repository, page 2202.02002, 2022.3" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.155, + 0.473, + 0.192 + ], + "angle": 0, + "content": "[55] Wei Yin, Yifan Liu, Chunhua Shen, and Youliang Yan. Enforcing geometric constraints of virtual normal for depth prediction. In Proc. IEEE Int. Conf. Comp. Vis., 2019. 2, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.194, + 0.472, + 0.243 + ], + "angle": 0, + "content": "[56] Wei Yin, Jianming Zhang, Oliver Wang, Simon Niklaus, Simon Chen, Yifan Liu, and Chunhua Shen. Towards accurate reconstruction of 3d scene shape from a single monocular image. IEEE Trans. Pattern Anal. Mach. Intell., 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.246, + 0.472, + 0.295 + ], + "angle": 0, + "content": "[57] Wei Yin, Jianming Zhang, Oliver Wang, Simon Niklaus, Long Mai, Simon Chen, and Chunhua Shen. Learning to recover 3d scene shape from a single image. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2021. 1, 2, 3, 4, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.297, + 0.472, + 0.347 + ], + "angle": 0, + "content": "[58] Zhichao Yin and Jianping Shi. Geonet: Unsupervised learning of dense depth, optical flow and camera pose. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1983-1992, 2018. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.349, + 0.472, + 0.398 + ], + "angle": 0, + "content": "[59] Weihao Yuan, Xiaodong Gu, Zuozhuo Dai, Siyu Zhu, and Ping Tan. New CRFs: Neural window fully-connected CRFs for monocular depth estimation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2022. 2, 3, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.401, + 0.472, + 0.45 + ], + "angle": 0, + "content": "[60] Chi Zhang, Wei Yin, Zhibin Wang, Gang Yu, Bin Fu, and Chunhua Shen. Hierarchical normalization for robust monocular depth estimation. Proc. Advances in Neural Inf. Process. Syst., 2022. 2, 3, 5, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.452, + 0.472, + 0.502 + ], + "angle": 0, + "content": "[61] Chi Zhang, Wei Yin, Gang Yu, Zhibin Wang, Tao Chen, Bin Fu, Joey Tianyi Zhou, and Chunhua Shen. Robust geometry-preserving depth estimation using differentiable rendering. In Proc. IEEE Int. Conf. Comp. Vis., 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.117, + 0.504, + 0.472, + 0.555 + ], + "angle": 0, + "content": "[62] Rui Zhu, Xingyi Yang, Yannick Hold-Geoffroy, Federico Perazzi, Jonathan Eisenmann, Kalyan Sunkavalli, and Manmohan Chandraker. Single view metrology in the wild. In Proc. Eur. Conf. Comp. Vis., pages 316-333. Springer, 2020." + }, + { + "type": "list", + "bbox": [ + 0.117, + 0.128, + 0.473, + 0.555 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.484, + 0.89, + 0.514, + 0.9 + ], + "angle": 0, + "content": "9053" + } + ] +] \ No newline at end of file diff --git a/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/6cc2d292-7284-48d5-98ac-76d175845d01_origin.pdf b/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/6cc2d292-7284-48d5-98ac-76d175845d01_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..bf9b35ca13fdb9985e9a92d9076fda0c012bfc3c --- /dev/null +++ b/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/6cc2d292-7284-48d5-98ac-76d175845d01_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:352be057e11744217e438f7c4177c5ecdf763e1b433ab8e1d7a479bff3391fcb +size 6482103 diff --git a/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/full.md b/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/full.md new file mode 100644 index 0000000000000000000000000000000000000000..cb7a33b55f02ade8c6a48b9198217e9d426cef35 --- /dev/null +++ b/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/full.md @@ -0,0 +1,289 @@ +# Metric3D: Towards Zero-shot Metric 3D Prediction from A Single Image + +Wei Yin $^{1*}$ , Chi Zhang $^{2*}$ , Hao Chen $^{3\dagger}$ , Zhipeng Cai $^{4}$ , Gang Yu $^{2}$ , Kaixuan Wang $^{1}$ , Xiaozhi Chen $^{1}$ , Chunhua Shen $^{3}$ + +$^{1}$ DJI Technology $^{2}$ Tencent $^{3}$ Zhejiang University $^{4}$ Intel Labs + +e-mail: $^1\mathrm{yvanwy}$ @outlook.com,{halfbullet.wang,xiaozhi.chen} $@$ dji.com; + +$^{2}$ johnczhang, skicyyu@tencent.com; + +3haochen.cad@zju.edu.cn, chunhua@me.com; 4zhipeng.cai@intel.com + +![](images/5fbb8b4b87a3aa86be43fc5fc38f8cee19fbac282b9f9338c9ba593883b20ae5.jpg) +Figure 1 - Illustration and applications of our metric 3D reconstruction method. Top (metrology): we use two phones (iPhone 12 and an Android phone) to capture the scene and measure the size of tables. With the photos' metadata, we perform 3D metric reconstruction and then measure tables' sizes (marked in red), which are very close to the ground truth (marked in blue). In contrast, the recent method LeReS [57] performs much worse and is unable to predict metric 3D by design. Bottom (dense SLAM mapping): existing SOTA mono-SLAM methods usually face scale drift problems (see the red arrows) in large-scale scenes and are unable to achieve the metric scale, while, naively inputting our metric depth, Droid-SLAM [44] can recover much more accurate trajectory and perform the metric dense mapping (see the red measurements). Note that all testing data are unseen to our model. + +# Abstract + +Reconstructing accurate 3D scenes from images is a long-standing vision task. Due to the ill-posedness of the single-image reconstruction problem, most well-established methods are built upon multi-view geometry. State-of-the-art (SOTA) monocular metric depth estimation meth + +ods can only handle a single camera model and are unable to perform mixed-data training due to metric ambiguity. Meanwhile, SOTA monocular methods trained on large mixed datasets achieve zero-shot generalization by learning affine-invariant depths, which cannot recover real-world metrics. In this work, we show that the key to a zero-shot single-view metric depth model lies in the combination of large-scale data training and resolving the metric ambiguity from various camera models. We propose a + +canonical camera space transformation module, which explicitly addresses the ambiguity problems and can be effortlessly plugged into existing monocular models. Equipped with our module, monocular models can be stably trained over 8 millions of images with thousands of camera models, resulting in zero-shot generalization to in-the-wild images with unseen camera settings. Experiments demonstrate SOTA performance of our method on 7 zero-shot benchmarks. Notably, our method won the championship in the 2nd Monocular Depth Estimation Challenge. Our method enables the accurate recovery of metric 3D structures on randomly collected internet images, paving the way for plausible single-image metrology. The potential benefits extend to downstream tasks, which can be significantly improved by simply plugging in our model. For example, our model relieves the scale drift issues of monocular-SLAM (Fig. 1), leading to high-quality metric scale dense mapping. The code is available at https://github.com/YvanYin/Metric3D. + +# 1. Introduction + +3D reconstruction from images is the core of many computer vision applications, such as autonomous driving and robotics. Main-stream methods leverage multi-view geometry [15] to confidently recover 3D structures. However, these methods cannot be applied to a single image, making 3D reconstruction hard without a prior. State-of-the-art transferable methods, such as MiDaS [32], LeReS [57], and HDN [60], learn such a prior from a large dataset, but they can only output affine-invariant depths, i.e., which are accurate only up to an unknown offset and scale. Though monocular metric depth estimation methods [59, 2] work on a single dataset with a single camera model, they cannot generalize to unseen cameras or scenes. This work aims to address the above problems by learning a zero-shot, single view, metric depth model. + +According to the predicted depth, existing methods are categorized into learning metric depth [59, 53, 2, 52], learning relative depth [48, 49, 6, 5], and learning affine-invariant depth [57, 56, 32, 31, 60]. Although the metric depth methods [59, 53, 55, 2, 52] have achieved impressive accuracy on various benchmarks, they must train and test on the dataset with the same camera intrinsics. Therefore, training datasets of metric depth methods are often small, as it is hard to collect a large dataset covering diverse scenes using one identical camera. The consequence is that all these models are not transferable - they generalize poorly to images in the wild, not to mention the camera parameters of test images can vary too. A compromise is to learn the relative depth [6, 48], which only represents the depth ordering information. Thus the application is very limited. Learning affine-invariant depth finds a trade-off between the above + +two categories of methods. With large-scale data, they decouple the metric information during training and achieve impressive robustness and generalization ability. The recent SOTA LeReS [57] can recover 3D scenes in the wild, but only up to an unknown scale and shift. + +This work focuses on learning a zero-shot transferable model to recover metric 3D from a single image. First, we analyze the metric ambiguity issues in monocular depth estimation and study different camera parameters in depth, including the pixel size, focal length, and sensor size. We observe that the focal length is the critical factor for accurate metric recovery. By design, LeReS [57] does not take the focal length information into account during training. As shown in Sec. 3.1, only from the image appearance, various focal lengths may cause metric ambiguity, thus they decouple the depth scale in training. To solve the problem of varying focal lengths, CamConv [11] encodes the camera model in the network, which enforces the network to implicitly understand camera models from the image appearance and then bridges the imaging size to the real-world size. However, training data contains limited images and types of cameras, which challenges data diversity and network capacity. In contrast, we propose a canonical camera transformation method in training. It is inspired by the human body reconstruction methods. To improve reconstructed shape quality on countless poses, they map all samples to a canonical pose space [29] to reduce pose variance. Similarly, we transform all training data to a canonical camera space where the processed images are coarsely regarded as captured by the same camera. To achieve such transformation, we propose two different methods. The first one tries to adjust the image appearance to simulate the canonical camera, while the other one transforms the ground-truth labels for supervision. Camera models are not encoded in the network, making our method easily applicable to existing architectures. During inference, a de-canonical transformation is employed to recover metric information. To further boost the depth accuracy, we propose a random proposal normalization loss. It is inspired by the scale-shift invariant loss [57, 32, 60], which decouples the depth scale to emphasize the single image's distribution. However, they perform on the whole image, which inevitably squeezes the fine-grained depth difference. We propose to randomly crop several patches from images and enforce the scale-shift invariant loss [57, 32] on them. Our loss emphasizes the local geometry and distribution of the single image. + +With the proposed method, we can easily scale up model training to 8 million images from 11 datasets of diverse scene types (indoor and outdoor) and camera models (tens of thousands of different cameras), leading to zero-shot transferability and a significantly improved accuracy. Our model can accurately reconstruct metric 3D from randomly collected Internet images, enabling plausible single-image + +metrology. Different from affine-invariant depth models, our model can also directly improve various downstream tasks. As an example (Fig. 1), with the predicted metric depths from our model, we can significantly reduce the scale drift of monocular SLAM [44, 43] systems, achieving much better mapping quality with real-world metric recovery. Our model also enables large-scale 3D reconstruction [17]. The model achieves the championship in the 2nd Monocular Depth Estimation Challenge [42]. To summarize, our main contributions are: + +- We propose a canonical and de-canonical camera transformation method to solve the metric depth ambiguity problems from various cameras setting. It enables the learning of strong zero-shot monocular metric depth models from large-scale datasets. +- We propose a random proposal normalization loss to boost the depth accuracy effectively; +- Our model achieves state-of-the-art performance on 7 zero-shot benchmarks. It can perform high-quality 3D metric structure recovery in the wild and benefit several downstream tasks, such as mono-SLAM [44, 27], 3D scene reconstruction [17], and metrology [62]. + +# 2. Related Work + +3D reconstruction from a single image. Reconstructing various objects from a single image has been well studied [1, 46, 47]. They can produce high-quality 3D models of cars, planes, tables, and human body [33, 34]. The main challenge is how to best recover objects' details, how to represent them with limited memory, and how to generalize to more diverse objects. However, all these methods rely on learning priors specific to a certain object class or instance, typically from 3D supervision, and can therefore not work for full scene reconstruction. Apart from these reconstructing objects works, several works focus on scene reconstruction [51] from a single image. Saxena et al. [35] construct the scene based on the assumption that the whole scene can be segmented into several small planes. With planes' orientation and location, the 3D structure can be represented. Recently, LeReS [57] propose to use a strong monocular depth estimation model to do scene reconstruction. However, they can only recover the shape up to a scale. Zhang et al. [61] recently propose a zero-shot geometry-preserving depth estimation model that is capable of making depth predictions up to an unknown scale, without requiring scale-invariant depth annotations for training. In contrast to these works, our method can recover the metric 3D structure. + +Supervised monocular depth estimation. After several benchmarks [39, 12] are established, neural network based methods [59, 55, 2, 25] have dominated since then. Several approaches regress the continuous depth from the aggregation of information in an image [10]. As depth distribution + +corresponding to different RGBs can vary to a large extent, some methods [55, 2] discretize the depth and formulate this problem to a classification [53], which often achieves better performance. The generalization issue of deep models for 3D metric recovery is related to two problems. The first one is to generalize to diverse scenes, while the other one is how to predict accurate metric information under various camera settings. The first problem has been well addressed by recent methods. Some works [49, 48, 53] propose to construct a large-scale relative depth dataset, such as DIW [5] and OASIS [6], and then they target learning the relative relations. However, the relative depth loses geometric structure information. To improve the recovered geometry quality, learning affine-invariant depth methods, such as MiDaS [32], LeReS [57], and HDN [60] are proposed. By mixing large-scale data, state-of-the-art performance and the generalization over scenes are improved continuously. Note that by design, these methods are unable to recover the metric information. How to achieve both strong generalization and accurate metric information over diverse scenes is the key problem that we attempt to tackle. + +Large-scale data training. Recently, various natural language problems and computer vision problems [54, 30, 22] have achieved impressive progress with large-scale data training. CLIP [30] is a promising classification model, which is trained on billions of paired image and language descriptions data. It achieved state-of-the-art performance over several classification benchmarks by zero-shot testing. For depth prediction, large-scale data training has been widely applied. Ranft et al. [32] mixed over 2 million data in training, LeReS [56] collected over 300 thousand data, Eftekhar et al. [9] also merged millions of data to build a strong depth prediction model. + +# 3. Method + +Preliminaries. We consider the pin-hole camera model with intrinsic parameters: $[[\hat{f} /\delta ,0,u_0],[0,\hat{f} /\delta ,v_0],[0,0,1]]$ where $\hat{f}$ is the focal length (in micrometers), $\delta$ is the pixel size (in micrometers), and $(u_0,v_0)$ is the principle center. $f = \hat{f} /\delta$ is the pixel-represented focal length used in vision algorithms. + +# 3.1. Metric Ambiguity Analysis + +Fig. 3 presents an example of photos taken by different cameras and at different distances. Only from the image's appearance, one may think the last two photos are taken at a similar location by the same camera. In fact, due to different focal lengths, these are captured at different locations. Thus, camera intrinsic parameters are critically important for the metric estimation from a single image, as otherwise, the problem is ill posed. To avoid such metric ambiguity, recent methods, such as MiDaS [32] and LeReS [57], + +![](images/7728a49709e41201261ada1ad4e63fa21cf7c8d4cf6c70b176d2fab65b966be8.jpg) +Figure 2 - Pipeline. Given an input image $I$ , we first transform it to the canonical space using CSTM. The transformed image $I_{c}$ is fed into a depth estimation model to produce the metric depth $D_{c}$ in the canonical space. During training, $D_{c}$ is supervised by a GT depth $D_{c}^{*}$ which is also transformed into the canonical space. In inference, after producing the metric depth $D_{c}$ in the canonical space, we perform a de-canonical transformation to convert it back to the space of the original input $I$ . The canonical and de-canonical transformations are executed using camera intrinsics. + +![](images/f5d089fa78130278337e20475ace3f4ba63612965458690c503c830081e447c7.jpg) +focal=26mm,depth=2m + +![](images/6e59db16f5bd876046238ea2174fc990347698e9ecc7020f5bf1573445e41404.jpg) +focal=52mm,depth=2m + +![](images/71e22d2db032afff640b57fb43959242720d3a29b19ee73703aa642713f2dda8.jpg) +focal=26mm,depth=1m +Figure 3 - Photos of a chair captured at different distances with different cameras. The first two photos are captured at the same distance but with different cameras, while the last one is taken at a closer distance with the same camera as the first one. + +decouple the metric from the supervision and compromise learning the affine-invariant depth. + +Fig. 4 (A) shows a simple pin-hole perspective projection. Object $A$ locating at $d_{a}$ is projected to $A^{\prime}$ . Based on the principle of similarity, we have the equation: + +$$ +d _ {a} = \hat {S} \left[ \frac {\hat {f}}{\hat {S} ^ {\prime}} \right] = \hat {S} \cdot \alpha \tag {1} +$$ + +where $\hat{S}$ and $\hat{S}^{\prime}$ are the real and imaging size respectively. $\hat{\tau}$ denotes variables are in the physical metric (e.g., millimeter). To recover $d_{a}$ , focal length, imaging size of the object, and real-world object size must be available. Estimating the focal length from a single image is a challenging and ill-posed problem. Although several methods [57, 16] have been explored, the accuracy is still far from being satisfactory. Here, we simplify the problem by assuming the focal length of a training/test image is available. Understanding the imaging size is much easier for a neural network. To obtain the real-world object size, a neural network needs to understand the semantic scene layout and the object, at which a neural network excels. We define $\alpha = \hat{f} / \hat{s}^{\prime}$ , so $d_{a}$ is proportional to $\alpha$ . + +We make the following observations regarding sensor size, pixel size, and focal length. + +O1: Sensor size and pixel size do not affect the metric depth estimation. Based on the perspective projection (Fig. 4 (A)), the sensor size only affects the field of view (FOV) and is irrelevant to $\alpha$ , thus does not affect the metric depth estimation. For the pixel size, we assume two cameras with different pixel sizes ( $\delta_{1} = 2\delta_{2}$ ) but the same focal + +length $\hat{f}$ to capture the same object locating at $d_{a}$ . Fig. 4 (B) shows their captured photos. According to the preliminaries, the pixel-represented focal length $f_{1} = \frac{1}{2} f_{2}$ . As the second camera has a smaller pixel size, although in the same projected imaging size $\hat{S}'$ , the pixel-represented image resolution is $S_1' = \frac{1}{2} S_2'$ . According to Eq. (1), $\frac{\hat{f}}{\delta_1 \cdot S_1'} = \frac{\hat{f}}{\delta_2 \cdot S_2'}$ , i.e. $\alpha_{1} = \alpha_{2}$ , so $d_{1} = d_{2}$ . Therefore, different camera sensors would not affect the metric depth estimation. + +O2: The focal length is vital for metric depth estimation. Fig. 3 shows the metric ambiguity issue caused by the unknown focal length. In Fig. 5, two cameras $(\hat{f}_1 = 2\hat{f}_2)$ are at distances $d_{1}$ and $d_{2}$ , the imaging sizes on cameras are the same. Only from the appearance, the network will be confused when supervised with different labels. Based on this, we propose a canonical camera transformation method to solve the supervision and image appearance conflicts. + +# 3.2. Canonical Camera Transformation + +The core idea is to set up a canonical camera space $((f_x^c, f_y^c), f_x^c = f_y^c = f^c$ in experiments) and transform all training data to this space. Consequently, all data can roughly be regarded as captured by the canonical camera. We propose two transformation methods, i.e. either on the input image $(\mathbf{I} \in \mathbb{R}^{H \times W \times 3})$ or the GT label $(\mathbf{D} \in \mathbb{R}^{H \times W})$ . + +![](images/ae32257d9e147b759fbfdcb3d01909c276e77aa6107e29be49a9cc992a4135e5.jpg) + +![](images/213abb90bd8d03fb56bbbd45bc9fd6ee300fff5c4a8d2efd313822101c308d31.jpg) + +![](images/fee3c55f6187142e4df0d5adffd27dc7939de79dd4b583d1693e55caf2483918.jpg) +Figure 4 - Pinhole camera model. (A) Object $A$ at the distance $d_{a}$ is projected to the image plane. (B) Using two cameras to capture the car. The left one has a larger pixel size. Although the projected imaging sizes are the same, the pixel-represented images (resolution) are different. +Figure 5 - Illustration of two cameras with different focal length at different distance. As $f_{1} = 2f_{2}$ and $d_{1} = 2d_{2}$ , $A$ is projected to two image planes with the same imaging size (i.e. $A_{1}' = A_{2}'$ ). + +The original intrinsics are $\{f, u_0, v_0\}$ . + +Method1: transforming depth labels (CSTM_label). Fig. 3's ambiguity is for depths. Thus our first method directly transforms the ground-truth depth labels to solve this problem. Specifically, we scale the ground-truth depth $(\mathbf{D}^{*})$ with the ratio $\omega_{d} = \frac{f^{c}}{f}$ in training, i.e., $\mathbf{D}_c^* = \omega_d\mathbf{D}^*$ . The original camera model is transformed to $\{f^c,u_0,v_0\}$ . In inference, the predicted depth $(\mathbf{D}_c)$ is in the canonical space and needs to perform a de-canonical transformation to recover the metric information, i.e., $\mathbf{D} = \frac{1}{\omega_d}\mathbf{D}_c$ . Note the input $\mathbf{I}$ does not perform any transformation, i.e., $\mathbf{I}_c = \mathbf{I}$ . + +Method2: transforming input images (CSTM_image). From another view, the ambiguity is caused by the similar image appearance. Thus this method is to transform the input image to simulate the canonical camera imaging effect. Specifically, the image $\mathbf{I}$ is resized with the ratio $\omega_{r} = \frac{f^{c}}{f}$ , i.e., $\mathbf{I}_c = \mathfrak{T}(\mathbf{I},\omega_r)$ , where $\mathfrak{T}(\cdot)$ denotes image resize. The optical center is resized, thus the canonical camera model is $\{f^c,\omega_ru_0,\omega_rv_0\}$ . The ground-truth labels are resized without any scaling, i.e., $\mathbf{D}_c^* = \mathfrak{T}(\mathbf{D}^*,\omega_r)$ . In inference, the de-canonical transformation is to resize the prediction to the original size without scaling, i.e., $\mathbf{D} = \mathfrak{T}(\mathbf{D}_c,\frac{1}{\omega_r})$ + +Fig. 2 shows the pipeline. After performing either transformation, we randomly crop a patch for training. The cropping only adjusts the FOV and the optical center, thus not causing any metric ambiguity issues. In the labels transformation method $\omega_{r} = 1$ and $\omega_{d} = \frac{f^{c}}{f}$ , while $\omega_{d} = 1$ and $\omega_{r} = \frac{f^{c}}{f}$ in the images transformation method. The training objective is as follows: + +$$ +\min _ {\theta} \left| \mathfrak {N} _ {d} \left(\mathbf {I} _ {c}, \theta\right) - \mathbf {D} _ {c} ^ {*} \right| \tag {2} +$$ + +where $\theta$ is the network's $(\mathcal{N}_d(\cdot))$ parameters, $\mathbf{D}_c^*$ and $\mathbf{I}_c$ are transformed ground-truth depth labels and images. + +Supervision. To further boost the performance, we propose a random proposal normalization loss (RPNL). The scale-shift invariant loss [32, 57] is widely applied for the affine-invariant depth estimation, which decouples the depth scale to emphasize the single image distribution. However, such normalization based on the whole image inevitably squeezes the fine-grained depth difference, particularly in close regions. Inspired by this, we propose to randomly crop several patches $(p_{i(i = 0,\dots,M)}\in \mathbb{R}^{h_i\times w_i})$ from the ground truth $\mathbf{D}_c^*$ and the predicted depth $\mathbf{D}_c$ . Then we employ the median absolute deviation normalization [40] for paired patches. By normalizing the local statistics, we can enhance local contrast. The loss function is as follows: + +$$ +\begin{array}{l} L _ {\mathrm {R P N L}} = \frac {1}{M N} \sum_ {p _ {i}} ^ {M} \sum_ {j} ^ {N} \left| \frac {d _ {p _ {i} , j} ^ {*} - \mu \left(d _ {p _ {i} , j} ^ {*}\right)}{\frac {1}{N} \sum_ {j} ^ {N} \left| d _ {p _ {i} , j} ^ {*} - \mu \left(d _ {p _ {i} , j} ^ {*}\right) \right|} - \right. \\ \frac {d _ {p _ {i , j}} - \mu \left(d _ {p _ {i , j}}\right)}{\frac {1}{N} \sum_ {j} ^ {N} \left| d _ {p _ {i , j}} - \mu \left(d _ {p _ {i , j}}\right) \right|} \tag {3} \\ \end{array} +$$ + +where $d^{*}\in \mathbf{D}_{c}^{*}$ and $d\in \mathbf{D}_c$ are the ground truth and predicted depth respectively. $\mu (\cdot)$ and is the median of depth. $M$ is the number of proposal crops, which is set to 32. During training, proposals are randomly cropped from the image by 0.125 to 0.5 of the original size. Furthermore, several other losses are employed, including the scale-invariant logarithmic loss [10] $L_{silog}$ , pair-wise normal regression loss [57] $L_{\mathrm{PWN}}$ , virtual normal loss [53] $L_{\mathrm{VNL}}$ . Note $L_{silog}$ is a variant of L1 loss. The overall losses are as follows. + +$$ +L = L _ {\mathrm {P W N}} + L _ {\mathrm {V N L}} + L _ {\text {s i l o g}} + L _ {\mathrm {R P N L}}. +$$ + +# 4. Experiments + +Dataset details. We collect 11 public RGB-D datasets, and over 8 million data for training. It spreads over diverse indoor and outdoor scenes. Note that all datasets have provided camera intrinsic parameters. Over 10K different cameras are included. Furthermore, we collect 7 unseen datasets for robustness and generalization evaluation. Details of employed data are reported in the supplementary materials. + +Implementation details. We use an UNet architecture with the ConvNext-large [26] backbone. ImageNet-22K pretrained weights are used for initialization. We use AdamW with a batch size of 192, an initial learning rate 0.0001 for all layers, and the polynomial decaying method with the power of 0.9. We use 48 A100 GPUs and train for 500K iterations. Following [53], we balance all datasets in a mini-batch to ensure each dataset accounts for an almost equal ratio. In training, images are processed by the LSTM, flipped horizontally with a $50\%$ chance, and then randomly cropped into $512 \times 960$ . In ablation studies, training settings are different as we sample 5000 images from each dataset for training and train on 8 GPUs for 150K iterations. + +Evaluation details. a) To show the robustness of our metric depth estimation method, we test on 8 zero-shot benchmarks, including NYUv2 [39], KITTI [12], NuScenes [4], 7-scenes [38], iBIMS-1 [19], DIODE [45], ETH3D [37]. Absolute relative error (AbsRel), the accuracy under threshold $(\delta_i < 1.25^i, i = 1,2,3)$ , root mean squared error (RMS), root mean squared error in log space (RMS_log), and log10 error (log10) metrics are employed. b) Furthermore, we also follow current affine-invariant depth benchmarks [57, 60] (Tab. 4) to evaluate the generalization ability on 5 zero-shot datasets, i.e., NYUv2, DIODE, ETH3D, ScanNet [7], and KITTI. We mainly compare with large-scale data trained models. Note that in this benchmark we follow existing methods to apply the scale shift alignment before evaluation. c) To evaluate our metric 3D reconstruction quality, we randomly sample 9 unseen scenes from NYUv2 and use colmap [36] to obtain the camera poses for multi-frame reconstruction. Chamfer $l_{1}$ distance and the F-score [18] are used to evaluate the reconstruction accuracy. d) In dense-SLAM experiments, following Li et al. [24], we + +Table 1 - Quantitative comparison on NYUv2 and KITTI benchmarks. Both datasets are unseen to our model, but we can achieve comparable performance with state-of-the-art methods. + +
NYUv2 Benchmark
Methodδ1↑δ2↑δ3↑AbsRel↓log10↓RMS↓
Li et al. [23]0.7880.9580.9910.1430.0630.635
Laina et al. [21]0.8110.9530.9880.1270.0550.573
VNL [55]0.8750.9760.9940.1080.0480.416
TrDepth [52]0.9000.9830.9960.1060.0450.365
Adabins [2]0.9030.9840.9970.1030.0440.364
NeWCRFs [59]0.9220.9920.9980.0950.0410.334
Ours LSTM_image0.9250.9830.9940.0920.0400.341
Ours LSTM_label0.9440.9860.9950.0830.0350.310
KITTI Benchmark
Methodδ1↑δ2↑δ3↑AbsRel↓RMS↓RMS_log↓
Guo et al. [14]0.9020.9690.9860.0903.2580.168
VNL [55]0.9380.9900.9980.0723.2580.117
TrDepth [52]0.9560.9940.9990.0642.7550.098
Adabins [2]0.9640.9950.9990.0582.3600.088
NeWCRFs [59]0.9740.9970.9990.0522.1290.079
Ours LSTM_image0.9670.9950.9990.0602.8430.087
Ours LSTM_label0.9640.9930.9980.0582.7700.092
+ +test on the KITTI odometry benchmark [12] and evaluate the average translational RMS drift $(\% ,t_{rel})$ and rotational RMS drift $(^{\circ} / 100m,r_{rel})$ errors [12]. + +# 4.1. Zero-shot Generalization Test + +Evaluation on metric depth benchmarks. To evaluate the accuracy of predicted metric depth, firstly, we compare with state-of-the-art (SOTA) metric depth prediction methods on NYUv2 [39], KITTI [13]. We use the same model to do all evaluations. Results are reported in Tab. 1. Without any fine-tuning or metric adjustment, we can achieve comparable performance with SOTA methods, which are trained on benchmarks for hundreds of epochs. + +Furthermore, we collect 6 unseen datasets to do more metric accuracy evaluation. These datasets contain a wide range of indoor and outdoor scenes. The camera models are also various, e.g. 7scenes has a short focal length (around 500), while ETH3D is 2000. We compare with the SOTA metric depth estimation methods and take their NYUv2 and KITTI models for indoor and outdoor scenes evaluation respectively. In Tab. 3, although 7Scenes is similar to NYUv2 and NuScenes is similar to KITTI, existing methods face a noticeable performance decrease. In contrast, our model is more robust. + +Generalization over diverse scenes. Affine-invariant depth benchmarks decouple the scale's effect, which aims to evaluate the model's generalization ability to diverse scenes. Recent impact works, such as MiDaS, LeReS, and DPT, achieved promising performance on them. Following them, we test on 5 datasets and manually align the scale and shift to the ground-truth depth before evaluation. Results are reported in Tab. 4. Although our method enforces the network to recover more challenging metric information, our method outperforms them by a large margin on most datasets. + +# 4.2. Applications Based on Our Method + +3D scene reconstruction. To demonstrate our work can recover the 3D metric shape in the wild, we first do the quantitative comparison on 9 NYUv2 scenes, which are unseen during training. We predict the per-frame metric depth and then fuse them together with provided camera poses. Results are reported in Tab. 2. We compare with the video consistent depth prediction method (RCVD [20]), the unsupervised video depth estimation method (SC-DepthV2 [3]), the 3D scene shape recovery method (LeReS [57]), affine-invariant depth estimation method (DPT [31]), and the multi-view stereo reconstruction method (DPSNet [17]). Apart from DPSNet and our method, other methods have to align the scale with the ground truth depth for each frame. Although our method does not aim for the video or multi-view reconstruction problem, our method can achieve promising consistency between frames and reconstruct much more accurate 3D scenes than others on these zero-shot scenes. From the qualitative comparison in Fig. 6, our reconstructions have much less noise and outliers. + +Dense-SLAM mapping. Monocular SLAM is an important robotics application. It takes a monocular video input to create the trajectory and dense 3D mapping. Owing to limited photometric and geometric constraints, existing methods face serious scale drift problems in large scenes and cannot recover the metric information. Our robust metric depth estimation method is a strong depth prior to the SLAM system. To demonstrate this benefit, we naively input our metric depth to the SOTA SLAM system, Droid-SLAM [44], and evaluate the trajectory on KITTI. We do not do any tuning on the original system. Trajectory comparisons are reported in Tab. 5. As Droid-SLAM can access accurate per-frame metric depth, like an RGB-D SLAM, the translation drift $(t_{rel})$ decreases significantly. Furthermore, with our depths, Droid-SLAM can perform denser and more accurate 3D mapping. An example is shown in Fig. 1 and more cases are shown in the supplementary materials. + +Metrology in the wild. To show the robustness and accuracy of our recovered metric 3D, we download Flickr photos captured by various cameras and collect coarse camera intrinsic parameters from their metadata. We use our CSTM_image model to reconstruct their metric shape and measure structures' sizes (marked in red in Fig. 7), while the ground-truth sizes are in blue. It shows that our measured sizes are very close to the ground-truth sizes. + +# 4.3. Ablation Study + +Ablation on canonical transformation. We study the effect of our proposed canonical transformation for the input images ('CSTM_input') and the canonical transformation for the ground-truth labels ('CSTM_output'). Results are reported in Tab. 6. We train the model on sampled mixed data (55K images) and test it on 6 datasets. A naive base + +Table 2 - Quantitative comparison of 3D scene reconstruction with LeReS [57], DPT [31], RCVD [20], SC-DepthV2 [3], and a learning-based MVS method (DPSNet [17]) on 9 unseen NYUv2 scenes. Apart from DPSNet and ours, other methods have to align the scale with ground truth depth for each frame. As a result, our reconstructed 3D scenes achieve the best performance. + +
MethodBasement_0001aBedroom_0015Dining_room_0004Kitchen_0008Classroom_0004Playroom_0002Office_0024Office_0004Dining_room_0033
C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑
RCVD [20]0.3640.2760.0740.5820.4620.2510.0530.6200.1870.3270.7910.1870.3240.2410.6460.2170.4450.253
SC-DepthV2 [3]0.2540.2750.0640.5470.7490.2290.0490.6240.1670.2670.4260.2630.4820.1380.5160.2440.3560.247
DPSNet [17]0.2430.2990.1950.2760.9950.1860.2690.2030.2960.1950.1410.4850.1990.3620.2100.4620.2220.493
DPT [57]0.6980.2510.2890.2260.3960.3640.1260.3880.7800.1930.6050.2690.4540.2450.3640.2790.7510.185
LeReS [57]0.0810.5550.0640.6160.2780.4270.1470.2890.1430.4800.1450.5030.4080.1760.0960.4970.2410.325
Ours0.0420.7360.0590.6100.1590.4850.0500.6450.1450.4450.0360.8140.0690.6380.0450.7000.0600.663
+ +![](images/4b56032377236421e63e29a801ac64b51cb28f90ada88d91e80ea778868ec6ba.jpg) + +![](images/be704abe952894c6b599b1ebf742a1181d88cb9052b8cdf52b3f477a266eabd7.jpg) + +![](images/248f8285bdcd75d34422951ecac8f47d7ddb90f03201e31939368693fc5a7794.jpg) + +![](images/c476038b4bc54ed56dbb362a7eb7aa27a0d178c4bd5df24c00362b2acd29e16e.jpg) +Figure 6 - Reconstruction of zero-shot scenes with multiple views. We sample several NYUv2 scenes for 3D reconstruction comparison. As our method can predict accurate metric depth, thus all predictions are fused together for scene reconstruction. By contrast, LeReS [57]'s depth is up to an unknown scale and shift, which causes noticeable distortions. DPSNet [17] is a multi-view stereo method, which cannot work well on low-texture regions. + +![](images/49948a8e4b0e06a210056b0a94bbeaa9a5c8a3b86022e55370cb41b602d08e82.jpg) +Figure 7 - Reconstruction of in-the-wild scenes. We collect several Flickr photos, which are captured by various cameras. With photos' metadata, we reconstruct the 3D metric shape and measure structures' sizes. Red and blue marks are ours and ground-truth sizes respectively. + +line ('Ours w/o LSTM') is to remove LSTM modules and enforce the same supervision as ours. Without LSTM, the model is unable to converge when training on mixed metric datasets and lost the metric prediction ability on zero-shot datasets. This is why mixed-data training methods compromise learning the affine-invariant depth to avoid metric issues. In contrast, our LSTM methods can enable the model to achieve the metric prediction ability, and they can achieve comparable performance. Tab. 1 also shows comparable performance. Therefore, both adjusting the supervision and the input image appearance during training can solve the metric ambiguity issues. Furthermore, we compare with CamConvs [11], which encodes the camera model in the decoder with a 4-channel feature. It employs the same training schedule, model, and training data as ours. This method enforces the network to implicitly understand various camera models from the image appearance and then bridges the imaging size to the real-world size. We believe that this + +Table 3 - Quantitative comparison with SOTA metric depth methods on 6 unseen benchmarks. For SOTA methods, we use their NYUv2 and KITTI models for indoor and outdoor scenes evaluation respectively, while we use the same model for all zero-shot testing. + +
MethodDIODE(Indoor) Indoor scenes (AbsRel↓/RMS↓)DIODE(Outdoor) Outdoor scenes (AbsRel↓/RMS↓)
Adabins [2]0.443 / 1.9630.212 / 0.9010.218 / 0.4280.865 / 10.351.271 / 6.1780.445 / 10.658
NewCRFs [59]0.404 / 1.8670.206 / 0.8610.240 / 0.4510.854 / 9.2280.890 / 5.0110.400 / 12.139
Ours_CSTM_label0.252 / 1.4400.160 / 0.5210.183 / 0.3630.414 / 6.9340.416 / 3.0170.154 / 7.097
Ours_CSTM_image0.268 / 1.4290.144 / 0.6460.189 / 0.3880.535 / 6.5070.342 / 2.9650.147 / 5.889
+ +Table 4 - Comparison with SOTA affine-invariant depth methods on 5 zero-shot transfer benchmarks. Our model significantly outperforms previous methods and sets new state-of-the-art. Following the benchmark setting, all methods have manually aligned the scale and shift. + +
MethodBackbone#ParamsNYUv2KITTIDIODEScanNetETH3DRank
AbsRel↓δ1↑AbsRel↓δ1↑AbsRel↓δ1↑AbsRel↓δ1↑AbsRel↓δ1↑
DiverseDepth [53]ResNeXt50 [50]25M0.1170.8750.1900.7040.3760.6310.1080.8820.2280.6947.7
MiDaS [32]ResNeXt10188M0.1110.8850.2360.6300.3320.7150.1110.8860.1840.7527.2
Leres [57]ResNeXt1010.0900.9160.1490.7840.2710.7660.0950.9120.1710.7775.4
Omnidata [9]ViT-base0.0740.9450.1490.8350.3390.7420.0770.9350.1660.7784.9
HDN [60]ViT-Large [8]306M0.0690.9480.1150.8670.2460.7800.0800.9390.1210.8333.7
DPT-large [31]ViT-Large0.0980.9030.100.9010.1820.7580.0780.9380.0780.9463.8
Ours LSTM_imageConvNeXt-large [26]198M0.0580.9630.0530.9650.2110.8250.0740.9420.0640.9651.3
Ours LSTM_labelConvNeXt-large0.0500.9660.0580.9700.2240.8050.0740.9410.0660.9641.8
+ +Table 5 - Comparison with SOTA SLAM methods on KITTI. We input predicted metric depth to the Droid-SLAM [44] ('Droid+Ours'), which outperforms others by a large margin on trajectory accuracy. + +
MethodSeq 00Seq 02Seq 05Seq 06Seq 08Seq 09Seq 10
Translational RMS drift (frel, ↓) / Rotational RMS drift (rrel, ↓)
GeoNet [58]27.6/5.7242.24/6.1420.12/7.679.28/4.3418.59/7.8523.94/9.8120.73/9.1
VISO2-M [41]12.66/2.739.47/1.1915.1/3.656.8/1.9314.82/2.523.69/1.2521.01/3.26
ORB-V2 [28]11.43/0.5810.34/0.269.04/0.2614.56/0.2611.46/0.289.3/0.262.57/0.32
Droid [44]33.9/0.2934.88/0.2723.4/0.2717.2/0.2639.6/0.3121.7/0.237/0.25
Droid+Ours1.44/0.372.64/0.291.44/0.250.6/0.22.2/0.31.63/0.222.73/0.23
+ +Table 6 - Effectiveness of our LSTM. CamConvs [11] directly encodes various camera models in the network, while we perform a simple yet effective transformation to solve the metric ambiguity. Without LSTM, the model cannot achieve transferable metric prediction ability. + +
MethodDDAD Test set of train.Lyft data (AbsRel↓)DSNS Zero-shot test setKITTI (AbsRel↓)NYU
w/o LSTM0.5300.5820.3941.000.5680.584
CamConvs [11]0.2950.3150.2130.4230.1780.333
Ours CSTM_image0.1900.2350.1820.1970.0970.210
Ours CSTM_label0.1830.2210.2010.2130.0810.212
+ +method challenges the data diversity and network capacity, thus our performance is better than theirs. + +Ablation on canonical space. We study the effect of the canonical camera here, i.e., the canonical focal length. We train the model on the small sampled dataset and test it on the validation set and testing data. The average AbsRel error is calculated. We experiment on 3 different focal lengths, i.e., 500, 1000, 1500. Experiments show that $\text{focal} = 1000$ has slightly better performance than others, see Fig. 8. Thus we set the canonical focal length to 1000 in our experiments. + +Effectiveness of the random proposal normalization loss. To show the effectiveness of our proposed random proposal normalization loss (RPNL), we experiment on the sampled small dataset. Results are shown in Tab. 7. We test on the DDAD, Lyft, DrivingStereo (DS), NuScenes (NS), KITTI, and NYUv2. The 'baseline' employs all losses except our RPNL. We compare it with 'baseline + RPNL' and 'baseline + SSIL [32]'. We can observe that our proposed + +![](images/f3b68f34b10e955b406332903e021da7291c37a39932bb3d224f61169b06a1f6.jpg) +Figure 8 - Effect of different canonical focal lengths. We experiment on different canonical focal lengths and find that too large or small focal lengths will impact the performance. + +Table 7 - Effectiveness of random proposal normalization loss. Baseline is supervised by $L_{\mathrm{PWN}} + L_{\mathrm{VNL}} + L_{\mathrm{silog}}$ . SSL is the scale-shift invariant loss proposed in [32]. + +
MethodDDAD Test set of train.Lyft data (AbsRel↓)DSNS Zero-shot test setKITTI (AbsRel↓)NYUv2
baseline0.2040.2510.1840.2070.1040.230
baseline + SSL [32]0.1970.2630.2590.2060.1050.216
baseline + RPNL0.1900.2350.1820.1970.0970.210
+ +random proposal normalization loss can further improve the performance. In contrast, the scale-shift invariant loss [32], which does the normalization on the whole image, can only slightly improve the performance. + +# 5. Conclusion + +In this paper, we tackle the problem of reconstructing the 3D metric scene from a single monocular image. To solve the depth ambiguity in image appearance caused by various focal lengths, we propose a canonical camera space transformation method. With our method, we can easily merge millions of data captured by 10k cameras to train one metric depth model. To improve the robustness, we collected over 8M data for training. Several zero-shot evaluations show the effectiveness and robustness of our work. We further show the ability to do metrology on randomly collected internet images and dense mapping on large-scale scenes. + +Acknowledgements This work was in part supported by National Key R&D Program of China (No. 2022ZD0118700). + +# References + +[1] Jonathan T Barron and Jitendra Malik. Shape, illumination, and reflectance from shading. IEEE Trans. Pattern Anal. Mach. Intell., 37(8):1670-1687, 2014. 3 +[2] Shariq Farooq Bhat, Ibrahim Alhashim, and Peter Wonka. Adabins: Depth estimation using adaptive bins. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 4009-4018, 2021. 2, 3, 6, 8 +[3] Jia-Wang Bian, Huangying Zhan, Naiyan Wang, Tat-Jin Chin, Chunhua Shen, and Ian Reid. Auto-rectify network for unsupervised indoor depth estimation. IEEE Trans. Pattern Anal. Mach. Intell., 2021. 6, 7 +[4] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 11621-11631, 2020. 5 +[5] Weifeng Chen, Zhao Fu, Dawei Yang, and Jia Deng. Single-image depth perception in the wild. In Proc. Advances in Neural Inf. Process. Syst., pages 730-738, 2016. 2, 3 +[6] Weifeng Chen, Shengyi Qian, David Fan, Noriyuki Kojima, Max Hamilton, and Jia Deng. Oasis: A large-scale dataset for single image 3d in the wild. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 679-688, 2020. 2, 3 +[7] Angela Dai, Angel X Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 5828-5839, 2017. 5 +[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. Proc. Int. Conf. Learn. Representations, 2021. 8 +[9] Ainaz Eftekhar, Alexander Sax, Jitendra Malik, and Amir Zamir. Omnidata: A scalable pipeline for making multi-task mid-level vision datasets from 3d scans. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 10786-10796, 2021. 3, 8 +[10] David Eigen, Christian Puhrsch, and Rob Fergus. Depth map prediction from a single image using a multi-scale deep network. In Proc. Advances in Neural Inf. Process. Syst., pages 2366-2374, 2014. 3, 5 +[11] Jose Facil, Benjamin Ummenhofer, Huizhong Zhou, Luis Montesano, Thomas Brox, and Javier Civera. CAM-Convs: camera-aware multi-scale convolutions for single-view depth. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 11826-11835, 2019. 2, 7, 8 +[12] Andreas Geiger, Philip Lenz, Christoph Stiller, and Raquel Urtasun. Vision meets robotics: The kitti dataset. Int. J. Robot. Res., 2013. 3, 5, 6 +[13] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the kitti vision benchmark suite. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 3354-3361. IEEE, 2012. 6 +[14] Xiaoyang Guo, Hongsheng Li, Shuai Yi, Jimmy Ren, and Xiaogang Wang. Learning monocular depth by distilling + +cross-domain stereo networks. In Proc. Eur. Conf. Comp. Vis., pages 484-500, 2018. 6 +[15] Richard Hartley and Andrew Zisserman. Multiple view geometry in computer vision. Cambridge university press, 2003. 2 +[16] Yannick Hold-Geoffroy, Kalyan Sunkavalli, Jonathan Eisenmann, Matthew Fisher, Emiliano Gambaretto, Sunil Hadap, and Jean-François Lalonde. A perceptual measure for deep single image camera calibration. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2354-2363, 2018. 4 +[17] Sunghoon Im, Hae-Gon Jeon, Stephen Lin, and In-So Kweon. Dpsnet: End-to-end deep plane sweep stereo. In Proc. Int. Conf. Learn. Representations, 2019. 3, 6, 7 +[18] Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: Benchmarking large-scale scene reconstruction. ACM Trans. Graph., 36(4):1-13, 2017. 5 +[19] Tobias Koch, Lukas Liebel, Friedrich Fraundorfer, and Marco Korner. Evaluation of cnn-based single-image depth estimation methods. In *Eur. Conf. Comput. Vis. Worksh.*, pages 0–0, 2018. 5 +[20] Johannes Kopf, Xuejian Rong, and Jia-Bin Huang. Robust consistent video depth estimation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2021. 6, 7 +[21] Iro Laina, Christian Rupprecht, Vasileios Belagiannis, Federico Tombari, and Nassir Navab. Deeper depth prediction with fully convolutional residual networks. In 2016 Fourth international conference on 3D vision (3DV), pages 239-248. IEEE, 2016. 6 +[22] John Lambert, Zhuang Liu, Ozan Sener, James Hays, and Vladlen Koltun. Mseg: A composite dataset for multi-domain semantic segmentation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2879-2888, 2020. 3 +[23] Jun Li, Reinhard Klein, and Angela Yao. A two-streamed network for estimating fine-scaled depth maps from singlergb images. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 3372-3380, 2017. 6 +[24] Shunkai Li, Xin Wu, Yingdian Cao, and Hongbin Zha. Generalizing to the open world: Deep visual odometry with online adaptation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 13184-13193, 2021. 5 +[25] Yifan Liu, Hao Chen, Yu Chen, Wei Yin, and Chunhua Shen. Generic perceptual loss for modeling structured output dependencies. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2021. 3 +[26] Zhuang Liu, Hanzi Mao, Chao-Yuan Wu, Christoph Feichtenhofer, Trevor Darrell, and Saining Xie. A convnet for the 2020s. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 11976-11986, 2022. 5, 8 +[27] Raul Mur-Artal and Juan D Tardós. Orb-slam2: An open-source slam system for monocular, stereo, and rgb-d cameras. IEEE transactions on robotics, 33(5):1255-1262, 2017. 3 +[28] Raul Mur-Artal and Juan D. Tardós. ORB-SLAM2: an open-source SLAM system for monocular, stereo and RGB-D cameras. IEEE Trans. Robot., 33(5):1255-1262, 2017. 8 +[29] Sida Peng, Shangzhan Zhang, Zhen Xu, Chen Geng, Boyi Jiang, Hujun Bao, and Xiaowei Zhou. Animatable neural + +implicit surfaces for creating avatars from videos. arXiv: Comp. Res. Repository, page 2203.08133, 2022. 2 +[30] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In Proc. Int. Conf. Mach. Learn., pages 8748-8763. PMLR, 2021. 3 +[31] René Ranftl, Alexey Bochkovskiy, and Vladlen Koltun. Vision transformers for dense prediction. In Proc. IEEE Int. Conf. Comp. Vis., pages 12179-12188, 2021. 2, 6, 7, 8 +[32] René Ranftl, Katrin Lasinger, David Hafner, Konrad Schindler, and Vladlen Koltun. Towards robust monocular depth estimation: Mixing datasets for zero-shot cross-dataset transfer. IEEE Trans. Pattern Anal. Mach. Intell., 2020. 2, 3, 5, 8 +[33] Shunsuke Saito, Zeng Huang, Ryota Natsume, Shigeo Morishima, Angjoo Kanazawa, and Hao Li. Pifu: Pixel-aligned implicit function for high-resolution clothed human digitization. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2304-2314, 2019. 3 +[34] Shunsuke Saito, Tomas Simon, Jason Saragih, and Hanbyul Joo. Pifuhd: Multi-level pixel-aligned implicit function for high-resolution 3d human digitization. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 84-93, 2020. 3 +[35] Ashutosh Saxena, Min Sun, and Andrew Y Ng. Make3d: Learning 3d scene structure from a single still image. IEEE Trans. Pattern Anal. Mach. Intell., 31(5):824-840, 2008. 3 +[36] Johannes Lutz Schonberger, Enliang Zheng, Marc Pollefeys, and Jan-Michael Frahm. Pixelwise view selection for unstructured multi-view stereo. In Proc. Eur. Conf. Comp. Vis., 2016. 5 +[37] Thomas Schops, Johannes L Schonberger, Silvano Galliani, Torsten Sattler, Konrad Schindler, Marc Pollefeys, and Andreas Geiger. A multi-view stereo benchmark with high-resolution images and multi-camera videos. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 3260-3269, 2017. 5 +[38] Jamie Shotton, Ben Glocker, Christopher Zach, Shahram Izadi, Antonio Criminisi, and Andrew Fitzgibbon. Scene coordinate regression forests for camera relocalization in rgb-d images. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2930-2937, 2013. 5 +[39] Nathan Silberman, Derek Hoiem, Pushmeet Kohli, and Rob Fergus. Indoor segmentation and support inference from rgbd images. In Proc. Eur. Conf. Comp. Vis., pages 746-760. Springer, 2012. 3, 5, 6 +[40] Dalwinder Singh and Birmohan Singh. Investigating the impact of data normalization on classification performance. Applied Soft Computing, 2019. 5 +[41] Shiyu Song, Manmohan Chandraker, and Clark C Guest. High accuracy monocular sfm and scale correction for autonomous driving. IEEE Trans. Pattern Anal. Mach. Intell., 38(4):730-743, 2015. 8 +[42] Jaime Spencer, C. Stella Qian, Michaela Trescakova, Chris Russell, Simon Hadfield, Erich W. Graf, Wendy J. Adams, Andrew J. Schofield, James Elder, Richard Bowden, Ali Anwar, Hao Chen, Xiaozhi Chen, Kai Cheng, Yuchao Dai, + +Huynh Thai Hoa, Sadat Hossain, Jianmian Huang, Mohan Jing, Bo Li, Chao Li, Baojun Li, Zhiwen Liu, Stefano Mattoccia, Siegfried Mercelis, Myungwoo Nam, Matteo Poggi, Xiaohua Qi, Jiahui Ren, Yang Tang, Fabio Tosi, Linh Trinh, S. M. Nadim Uddin, Khan Muhammad Umair, Kaixuan Wang, Yufei Wang, Yixing Wang, Mochu Xiang, Guangkai Xu, Wei Yin, Jun Yu, Qi Zhang, and Chaoqiang Zhao. The second monocular depth estimation challenge. In IEEE Conf. Comput. Vis. Pattern Recog. Worksh., pages 3063-3075, June 2023. 3 +[43] Libo Sun, Wei Yin, Enze Xie, Zhengrong Li, Changming Sun, and Chunhua Shen. Improving monocular visual odometry using learned depth. IEEE Transactions on Robotics, 38(5):3173-3186, 2022. 3 +[44] Zachary Teed and Jia Deng. Droid-slam: Deep visual slam for monocular, stereo, and rgb-d cameras. volume 34, pages 16558-16569, 2021. 1, 3, 6, 8 +[45] Igor Vasiljevic, Nick Kolkin, Shanyi Zhang, Ruotian Luo, Haochen Wang, Falcon Z Dai, Andrea F Daniele, Mohammadreza Mostajabi, Steven Basart, Matthew R Walter, et al. Diode: A dense indoor and outdoor depth dataset. arXiv: Comp. Res. Repository, page 1908.00463, 2019. 5 +[46] Nanyang Wang, Yinda Zhang, Zhuwen Li, Yanwei Fu, Wei Liu, and Yu-Gang Jiang. Pixel2mesh: Generating 3d mesh models from single RGB images. In Proc. Eur. Conf. Comp. Vis., pages 52-67, 2018. 3 +[47] Jiajun Wu, Chengkai Zhang, Xiuming Zhang, Zhoutong Zhang, William Freeman, and Joshua Tenenbaum. Learning shape priors for single-view 3d completion and reconstruction. In Proc. Eur. Conf. Comp. Vis., pages 646-662, 2018. 3 +[48] Ke Xian, Chunhua Shen, Zhiguo Cao, Hao Lu, Yang Xiao, Ruibo Li, and Zhenbo Luo. Monocular relative depth perception with web stereo data supervision. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 311-320, 2018. 2, 3 +[49] Ke Xian, Jianming Zhang, Oliver Wang, Long Mai, Zhe Lin, and Zhiguo Cao. Structure-guided ranking loss for single image depth prediction. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 611-620, 2020. 2, 3 +[50] Saining Xie, Ross Girshick, Piotr Dólar, Zhuowen Tu, and Kaiming He. Aggregated residual transformations for deep neural networks. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 1492-1500, 2017. 8 +[51] Guangkai Xu, Wei Yin, Hao Chen, Chunhua Shen, Kai Cheng, and Feng Zhao. Pose-free 3d scene reconstruction with frozen depth models. In Proc. IEEE Int. Conf. Comp. Vis., 2023. 3 +[52] Guanglei Yang, Hao Tang, Mingli Ding, Nicu Sebe, and Elisa Ricci. Transformer-based attention networks for continuous pixel-wise prediction. In Proc. IEEE Int. Conf. Comp. Vis., 2021. 2, 6 +[53] Wei Yin, Yifan Liu, and Chunhua Shen. Virtual normal: Enforcing geometric constraints for accurate and robust depth prediction. IEEE Trans. Pattern Anal. Mach. Intell., 2021. 2, 3, 5, 8 +[54] Wei Yin, Yifan Liu, Chunhua Shen, Anton van den Hengel, and Baichuan Sun. The devil is in the labels: Semantic seg + +mentation from sentences. arXiv: Comp. Res. Repository, page 2202.02002, 2022.3 +[55] Wei Yin, Yifan Liu, Chunhua Shen, and Youliang Yan. Enforcing geometric constraints of virtual normal for depth prediction. In Proc. IEEE Int. Conf. Comp. Vis., 2019. 2, 3, 6 +[56] Wei Yin, Jianming Zhang, Oliver Wang, Simon Niklaus, Simon Chen, Yifan Liu, and Chunhua Shen. Towards accurate reconstruction of 3d scene shape from a single monocular image. IEEE Trans. Pattern Anal. Mach. Intell., 2022. 2, 3 +[57] Wei Yin, Jianming Zhang, Oliver Wang, Simon Niklaus, Long Mai, Simon Chen, and Chunhua Shen. Learning to recover 3d scene shape from a single image. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2021. 1, 2, 3, 4, 5, 6, 7, 8 +[58] Zhichao Yin and Jianping Shi. Geonet: Unsupervised learning of dense depth, optical flow and camera pose. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1983-1992, 2018. 8 +[59] Weihao Yuan, Xiaodong Gu, Zuozhuo Dai, Siyu Zhu, and Ping Tan. New CRFs: Neural window fully-connected CRFs for monocular depth estimation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2022. 2, 3, 6, 8 +[60] Chi Zhang, Wei Yin, Zhibin Wang, Gang Yu, Bin Fu, and Chunhua Shen. Hierarchical normalization for robust monocular depth estimation. Proc. Advances in Neural Inf. Process. Syst., 2022. 2, 3, 5, 8 +[61] Chi Zhang, Wei Yin, Gang Yu, Zhibin Wang, Tao Chen, Bin Fu, Joey Tianyi Zhou, and Chunhua Shen. Robust geometry-preserving depth estimation using differentiable rendering. In Proc. IEEE Int. Conf. Comp. Vis., 2023. 3 +[62] Rui Zhu, Xingyi Yang, Yannick Hold-Geoffroy, Federico Perazzi, Jonathan Eisenmann, Kalyan Sunkavalli, and Manmohan Chandraker. Single view metrology in the wild. In Proc. Eur. Conf. Comp. Vis., pages 316-333. Springer, 2020. \ No newline at end of file diff --git a/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/images.zip b/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..da966458e62782809236df02ea31c0c903e1ddac --- /dev/null +++ b/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:2258d2bf0531fc708e5428e86c3ea2f8999ef056f3105dd4e372a0c602738a87 +size 809047 diff --git a/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/layout.json b/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..8eda26f28e0ffc661ebc5a0cbbcb440f26a55276 --- /dev/null +++ b/2023/Metric3D_ Towards Zero-shot Metric 3D Prediction from A Single Image/layout.json @@ -0,0 +1,8929 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 91, + 128, + 503, + 145 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 128, + 503, + 145 + ], + "spans": [ + { + "bbox": [ + 91, + 128, + 503, + 145 + ], + "type": "text", + "content": "Metric3D: Towards Zero-shot Metric 3D Prediction from A Single Image" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "spans": [ + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "text", + "content": "Wei Yin" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "text", + "content": ", Chi Zhang" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "inline_equation", + "content": "^{2*}" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "text", + "content": ", Hao Chen" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "inline_equation", + "content": "^{3\\dagger}" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "text", + "content": ", Zhipeng Cai" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "text", + "content": ", Gang Yu" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "text", + "content": ", Kaixuan Wang" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "text", + "content": ", Xiaozhi Chen" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "text", + "content": ", Chunhua Shen" + }, + { + "bbox": [ + 110, + 163, + 485, + 190 + ], + "type": "inline_equation", + "content": "^{3}" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 135, + 193, + 460, + 207 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 135, + 193, + 460, + 207 + ], + "spans": [ + { + "bbox": [ + 135, + 193, + 460, + 207 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 135, + 193, + 460, + 207 + ], + "type": "text", + "content": " DJI Technology " + }, + { + "bbox": [ + 135, + 193, + 460, + 207 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 135, + 193, + 460, + 207 + ], + "type": "text", + "content": " Tencent " + }, + { + "bbox": [ + 135, + 193, + 460, + 207 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 135, + 193, + 460, + 207 + ], + "type": "text", + "content": " Zhejiang University " + }, + { + "bbox": [ + 135, + 193, + 460, + 207 + ], + "type": "inline_equation", + "content": "^{4}" + }, + { + "bbox": [ + 135, + 193, + 460, + 207 + ], + "type": "text", + "content": " Intel Labs" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 118, + 207, + 476, + 220 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 118, + 207, + 476, + 220 + ], + "spans": [ + { + "bbox": [ + 118, + 207, + 476, + 220 + ], + "type": "text", + "content": "e-mail: " + }, + { + "bbox": [ + 118, + 207, + 476, + 220 + ], + "type": "inline_equation", + "content": "^1\\mathrm{yvanwy}" + }, + { + "bbox": [ + 118, + 207, + 476, + 220 + ], + "type": "text", + "content": " @outlook.com,{halfbullet.wang,xiaozhi.chen} " + }, + { + "bbox": [ + 118, + 207, + 476, + 220 + ], + "type": "inline_equation", + "content": "@" + }, + { + "bbox": [ + 118, + 207, + 476, + 220 + ], + "type": "text", + "content": " dji.com;" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 204, + 220, + 392, + 232 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 204, + 220, + 392, + 232 + ], + "spans": [ + { + "bbox": [ + 204, + 220, + 392, + 232 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 204, + 220, + 392, + 232 + ], + "type": "text", + "content": "johnczhang, skicyyu@tencent.com;" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 130, + 232, + 465, + 245 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 130, + 232, + 465, + 245 + ], + "spans": [ + { + "bbox": [ + 130, + 232, + 465, + 245 + ], + "type": "text", + "content": "3haochen.cad@zju.edu.cn, chunhua@me.com; 4zhipeng.cai@intel.com" + } + ] + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 93, + 270, + 503, + 506 + ], + "blocks": [ + { + "bbox": [ + 93, + 270, + 503, + 506 + ], + "lines": [ + { + "bbox": [ + 93, + 270, + 503, + 506 + ], + "spans": [ + { + "bbox": [ + 93, + 270, + 503, + 506 + ], + "type": "image", + "image_path": "5fbb8b4b87a3aa86be43fc5fc38f8cee19fbac282b9f9338c9ba593883b20ae5.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 72, + 513, + 523, + 566 + ], + "lines": [ + { + "bbox": [ + 72, + 513, + 523, + 566 + ], + "spans": [ + { + "bbox": [ + 72, + 513, + 523, + 566 + ], + "type": "text", + "content": "Figure 1 - Illustration and applications of our metric 3D reconstruction method. Top (metrology): we use two phones (iPhone 12 and an Android phone) to capture the scene and measure the size of tables. With the photos' metadata, we perform 3D metric reconstruction and then measure tables' sizes (marked in red), which are very close to the ground truth (marked in blue). In contrast, the recent method LeReS [57] performs much worse and is unable to predict metric 3D by design. Bottom (dense SLAM mapping): existing SOTA mono-SLAM methods usually face scale drift problems (see the red arrows) in large-scale scenes and are unable to achieve the metric scale, while, naively inputting our metric depth, Droid-SLAM [44] can recover much more accurate trajectory and perform the metric dense mapping (see the red measurements). Note that all testing data are unseen to our model." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "bbox": [ + 157, + 576, + 201, + 588 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 157, + 576, + 201, + 588 + ], + "spans": [ + { + "bbox": [ + 157, + 576, + 201, + 588 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 69, + 601, + 289, + 656 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 601, + 289, + 656 + ], + "spans": [ + { + "bbox": [ + 69, + 601, + 289, + 656 + ], + "type": "text", + "content": "Reconstructing accurate 3D scenes from images is a long-standing vision task. Due to the ill-posedness of the single-image reconstruction problem, most well-established methods are built upon multi-view geometry. State-of-the-art (SOTA) monocular metric depth estimation meth" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 578, + 526, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 578, + 526, + 677 + ], + "spans": [ + { + "bbox": [ + 306, + 578, + 526, + 677 + ], + "type": "text", + "content": "ods can only handle a single camera model and are unable to perform mixed-data training due to metric ambiguity. Meanwhile, SOTA monocular methods trained on large mixed datasets achieve zero-shot generalization by learning affine-invariant depths, which cannot recover real-world metrics. In this work, we show that the key to a zero-shot single-view metric depth model lies in the combination of large-scale data training and resolving the metric ambiguity from various camera models. We propose a" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 85, + 36, + 127, + 64 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 85, + 36, + 127, + 64 + ], + "spans": [ + { + "bbox": [ + 85, + 36, + 127, + 64 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 159, + 34, + 478, + 45 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 159, + 34, + 478, + 45 + ], + "spans": [ + { + "bbox": [ + 159, + 34, + 478, + 45 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 206, + 45, + 430, + 56 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 206, + 45, + 430, + 56 + ], + "spans": [ + { + "bbox": [ + 206, + 45, + 430, + 56 + ], + "type": "text", + "content": "Except for this watermark, it is identical to the accepted version;" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 189, + 56, + 448, + 67 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 189, + 56, + 448, + 67 + ], + "spans": [ + { + "bbox": [ + 189, + 56, + 448, + 67 + ], + "type": "text", + "content": "the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 80, + 668, + 144, + 677 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 80, + 668, + 144, + 677 + ], + "spans": [ + { + "bbox": [ + 80, + 668, + 144, + 677 + ], + "type": "text", + "content": "*Equal contributions." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 81, + 677, + 150, + 686 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 81, + 677, + 150, + 686 + ], + "spans": [ + { + "bbox": [ + 81, + 677, + 150, + 686 + ], + "type": "text", + "content": "†Corresponding author." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 296, + 704, + 314, + 713 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 704, + 314, + 713 + ], + "spans": [ + { + "bbox": [ + 296, + 704, + 314, + 713 + ], + "type": "text", + "content": "9043" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 67, + 100, + 290, + 308 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 100, + 290, + 308 + ], + "spans": [ + { + "bbox": [ + 67, + 100, + 290, + 308 + ], + "type": "text", + "content": "canonical camera space transformation module, which explicitly addresses the ambiguity problems and can be effortlessly plugged into existing monocular models. Equipped with our module, monocular models can be stably trained over 8 millions of images with thousands of camera models, resulting in zero-shot generalization to in-the-wild images with unseen camera settings. Experiments demonstrate SOTA performance of our method on 7 zero-shot benchmarks. Notably, our method won the championship in the 2nd Monocular Depth Estimation Challenge. Our method enables the accurate recovery of metric 3D structures on randomly collected internet images, paving the way for plausible single-image metrology. The potential benefits extend to downstream tasks, which can be significantly improved by simply plugging in our model. For example, our model relieves the scale drift issues of monocular-SLAM (Fig. 1), leading to high-quality metric scale dense mapping. The code is available at https://github.com/YvanYin/Metric3D." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 70, + 329, + 144, + 340 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 329, + 144, + 340 + ], + "spans": [ + { + "bbox": [ + 70, + 329, + 144, + 340 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 67, + 347, + 290, + 511 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 347, + 290, + 511 + ], + "spans": [ + { + "bbox": [ + 67, + 347, + 290, + 511 + ], + "type": "text", + "content": "3D reconstruction from images is the core of many computer vision applications, such as autonomous driving and robotics. Main-stream methods leverage multi-view geometry [15] to confidently recover 3D structures. However, these methods cannot be applied to a single image, making 3D reconstruction hard without a prior. State-of-the-art transferable methods, such as MiDaS [32], LeReS [57], and HDN [60], learn such a prior from a large dataset, but they can only output affine-invariant depths, i.e., which are accurate only up to an unknown offset and scale. Though monocular metric depth estimation methods [59, 2] work on a single dataset with a single camera model, they cannot generalize to unseen cameras or scenes. This work aims to address the above problems by learning a zero-shot, single view, metric depth model." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 67, + 512, + 290, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 512, + 290, + 687 + ], + "spans": [ + { + "bbox": [ + 67, + 512, + 290, + 687 + ], + "type": "text", + "content": "According to the predicted depth, existing methods are categorized into learning metric depth [59, 53, 2, 52], learning relative depth [48, 49, 6, 5], and learning affine-invariant depth [57, 56, 32, 31, 60]. Although the metric depth methods [59, 53, 55, 2, 52] have achieved impressive accuracy on various benchmarks, they must train and test on the dataset with the same camera intrinsics. Therefore, training datasets of metric depth methods are often small, as it is hard to collect a large dataset covering diverse scenes using one identical camera. The consequence is that all these models are not transferable - they generalize poorly to images in the wild, not to mention the camera parameters of test images can vary too. A compromise is to learn the relative depth [6, 48], which only represents the depth ordering information. Thus the application is very limited. Learning affine-invariant depth finds a trade-off between the above" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 304, + 100, + 526, + 155 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 100, + 526, + 155 + ], + "spans": [ + { + "bbox": [ + 304, + 100, + 526, + 155 + ], + "type": "text", + "content": "two categories of methods. With large-scale data, they decouple the metric information during training and achieve impressive robustness and generalization ability. The recent SOTA LeReS [57] can recover 3D scenes in the wild, but only up to an unknown scale and shift." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 157, + 526, + 608 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 157, + 526, + 608 + ], + "spans": [ + { + "bbox": [ + 304, + 157, + 526, + 608 + ], + "type": "text", + "content": "This work focuses on learning a zero-shot transferable model to recover metric 3D from a single image. First, we analyze the metric ambiguity issues in monocular depth estimation and study different camera parameters in depth, including the pixel size, focal length, and sensor size. We observe that the focal length is the critical factor for accurate metric recovery. By design, LeReS [57] does not take the focal length information into account during training. As shown in Sec. 3.1, only from the image appearance, various focal lengths may cause metric ambiguity, thus they decouple the depth scale in training. To solve the problem of varying focal lengths, CamConv [11] encodes the camera model in the network, which enforces the network to implicitly understand camera models from the image appearance and then bridges the imaging size to the real-world size. However, training data contains limited images and types of cameras, which challenges data diversity and network capacity. In contrast, we propose a canonical camera transformation method in training. It is inspired by the human body reconstruction methods. To improve reconstructed shape quality on countless poses, they map all samples to a canonical pose space [29] to reduce pose variance. Similarly, we transform all training data to a canonical camera space where the processed images are coarsely regarded as captured by the same camera. To achieve such transformation, we propose two different methods. The first one tries to adjust the image appearance to simulate the canonical camera, while the other one transforms the ground-truth labels for supervision. Camera models are not encoded in the network, making our method easily applicable to existing architectures. During inference, a de-canonical transformation is employed to recover metric information. To further boost the depth accuracy, we propose a random proposal normalization loss. It is inspired by the scale-shift invariant loss [57, 32, 60], which decouples the depth scale to emphasize the single image's distribution. However, they perform on the whole image, which inevitably squeezes the fine-grained depth difference. We propose to randomly crop several patches from images and enforce the scale-shift invariant loss [57, 32] on them. Our loss emphasizes the local geometry and distribution of the single image." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 609, + 527, + 688 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 609, + 527, + 688 + ], + "spans": [ + { + "bbox": [ + 304, + 609, + 527, + 688 + ], + "type": "text", + "content": "With the proposed method, we can easily scale up model training to 8 million images from 11 datasets of diverse scene types (indoor and outdoor) and camera models (tens of thousands of different cameras), leading to zero-shot transferability and a significantly improved accuracy. Our model can accurately reconstruct metric 3D from randomly collected Internet images, enabling plausible single-image" + } + ] + } + ], + "index": 6 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 704, + 315, + 714 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 704, + 315, + 714 + ], + "spans": [ + { + "bbox": [ + 296, + 704, + 315, + 714 + ], + "type": "text", + "content": "9044" + } + ] + } + ], + "index": 7 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 68, + 100, + 290, + 209 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 100, + 290, + 209 + ], + "spans": [ + { + "bbox": [ + 68, + 100, + 290, + 209 + ], + "type": "text", + "content": "metrology. Different from affine-invariant depth models, our model can also directly improve various downstream tasks. As an example (Fig. 1), with the predicted metric depths from our model, we can significantly reduce the scale drift of monocular SLAM [44, 43] systems, achieving much better mapping quality with real-world metric recovery. Our model also enables large-scale 3D reconstruction [17]. The model achieves the championship in the 2nd Monocular Depth Estimation Challenge [42]. To summarize, our main contributions are:" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 79, + 217, + 290, + 352 + ], + "type": "list", + "angle": 0, + "index": 4, + "blocks": [ + { + "bbox": [ + 79, + 217, + 290, + 272 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 79, + 217, + 290, + 272 + ], + "spans": [ + { + "bbox": [ + 79, + 217, + 290, + 272 + ], + "type": "text", + "content": "- We propose a canonical and de-canonical camera transformation method to solve the metric depth ambiguity problems from various cameras setting. It enables the learning of strong zero-shot monocular metric depth models from large-scale datasets." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 80, + 274, + 289, + 295 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 80, + 274, + 289, + 295 + ], + "spans": [ + { + "bbox": [ + 80, + 274, + 289, + 295 + ], + "type": "text", + "content": "- We propose a random proposal normalization loss to boost the depth accuracy effectively;" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 80, + 297, + 290, + 352 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 80, + 297, + 290, + 352 + ], + "spans": [ + { + "bbox": [ + 80, + 297, + 290, + 352 + ], + "type": "text", + "content": "- Our model achieves state-of-the-art performance on 7 zero-shot benchmarks. It can perform high-quality 3D metric structure recovery in the wild and benefit several downstream tasks, such as mono-SLAM [44, 27], 3D scene reconstruction [17], and metrology [62]." + } + ] + } + ], + "index": 3 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 69, + 361, + 149, + 372 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 361, + 149, + 372 + ], + "spans": [ + { + "bbox": [ + 69, + 361, + 149, + 372 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 68, + 380, + 290, + 631 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 380, + 290, + 631 + ], + "spans": [ + { + "bbox": [ + 68, + 380, + 290, + 631 + ], + "type": "text", + "content": "3D reconstruction from a single image. Reconstructing various objects from a single image has been well studied [1, 46, 47]. They can produce high-quality 3D models of cars, planes, tables, and human body [33, 34]. The main challenge is how to best recover objects' details, how to represent them with limited memory, and how to generalize to more diverse objects. However, all these methods rely on learning priors specific to a certain object class or instance, typically from 3D supervision, and can therefore not work for full scene reconstruction. Apart from these reconstructing objects works, several works focus on scene reconstruction [51] from a single image. Saxena et al. [35] construct the scene based on the assumption that the whole scene can be segmented into several small planes. With planes' orientation and location, the 3D structure can be represented. Recently, LeReS [57] propose to use a strong monocular depth estimation model to do scene reconstruction. However, they can only recover the shape up to a scale. Zhang et al. [61] recently propose a zero-shot geometry-preserving depth estimation model that is capable of making depth predictions up to an unknown scale, without requiring scale-invariant depth annotations for training. In contrast to these works, our method can recover the metric 3D structure." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 68, + 632, + 290, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 632, + 290, + 687 + ], + "spans": [ + { + "bbox": [ + 68, + 632, + 290, + 687 + ], + "type": "text", + "content": "Supervised monocular depth estimation. After several benchmarks [39, 12] are established, neural network based methods [59, 55, 2, 25] have dominated since then. Several approaches regress the continuous depth from the aggregation of information in an image [10]. As depth distribution" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 100, + 526, + 330 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 100, + 526, + 330 + ], + "spans": [ + { + "bbox": [ + 304, + 100, + 526, + 330 + ], + "type": "text", + "content": "corresponding to different RGBs can vary to a large extent, some methods [55, 2] discretize the depth and formulate this problem to a classification [53], which often achieves better performance. The generalization issue of deep models for 3D metric recovery is related to two problems. The first one is to generalize to diverse scenes, while the other one is how to predict accurate metric information under various camera settings. The first problem has been well addressed by recent methods. Some works [49, 48, 53] propose to construct a large-scale relative depth dataset, such as DIW [5] and OASIS [6], and then they target learning the relative relations. However, the relative depth loses geometric structure information. To improve the recovered geometry quality, learning affine-invariant depth methods, such as MiDaS [32], LeReS [57], and HDN [60] are proposed. By mixing large-scale data, state-of-the-art performance and the generalization over scenes are improved continuously. Note that by design, these methods are unable to recover the metric information. How to achieve both strong generalization and accurate metric information over diverse scenes is the key problem that we attempt to tackle." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 331, + 526, + 462 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 331, + 526, + 462 + ], + "spans": [ + { + "bbox": [ + 304, + 331, + 526, + 462 + ], + "type": "text", + "content": "Large-scale data training. Recently, various natural language problems and computer vision problems [54, 30, 22] have achieved impressive progress with large-scale data training. CLIP [30] is a promising classification model, which is trained on billions of paired image and language descriptions data. It achieved state-of-the-art performance over several classification benchmarks by zero-shot testing. For depth prediction, large-scale data training has been widely applied. Ranft et al. [32] mixed over 2 million data in training, LeReS [56] collected over 300 thousand data, Eftekhar et al. [9] also merged millions of data to build a strong depth prediction model." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 474, + 358, + 487 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 474, + 358, + 487 + ], + "spans": [ + { + "bbox": [ + 306, + 474, + 358, + 487 + ], + "type": "text", + "content": "3. Method" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "spans": [ + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "type": "text", + "content": "Preliminaries. We consider the pin-hole camera model with intrinsic parameters: " + }, + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "type": "inline_equation", + "content": "[[\\hat{f} /\\delta ,0,u_0],[0,\\hat{f} /\\delta ,v_0],[0,0,1]]" + }, + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "type": "inline_equation", + "content": "\\hat{f}" + }, + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "type": "text", + "content": " is the focal length (in micrometers), " + }, + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "type": "inline_equation", + "content": "\\delta" + }, + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "type": "text", + "content": " is the pixel size (in micrometers), and " + }, + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "type": "inline_equation", + "content": "(u_0,v_0)" + }, + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "type": "text", + "content": " is the principle center. " + }, + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "type": "inline_equation", + "content": "f = \\hat{f} /\\delta" + }, + { + "bbox": [ + 304, + 494, + 526, + 561 + ], + "type": "text", + "content": " is the pixel-represented focal length used in vision algorithms." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 570, + 443, + 582 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 570, + 443, + 582 + ], + "spans": [ + { + "bbox": [ + 306, + 570, + 443, + 582 + ], + "type": "text", + "content": "3.1. Metric Ambiguity Analysis" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 588, + 526, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 588, + 526, + 687 + ], + "spans": [ + { + "bbox": [ + 304, + 588, + 526, + 687 + ], + "type": "text", + "content": "Fig. 3 presents an example of photos taken by different cameras and at different distances. Only from the image's appearance, one may think the last two photos are taken at a similar location by the same camera. In fact, due to different focal lengths, these are captured at different locations. Thus, camera intrinsic parameters are critically important for the metric estimation from a single image, as otherwise, the problem is ill posed. To avoid such metric ambiguity, recent methods, such as MiDaS [32] and LeReS [57]," + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 704, + 315, + 713 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 704, + 315, + 713 + ], + "spans": [ + { + "bbox": [ + 296, + 704, + 315, + 713 + ], + "type": "text", + "content": "9045" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 91, + 99, + 501, + 193 + ], + "blocks": [ + { + "bbox": [ + 91, + 99, + 501, + 193 + ], + "lines": [ + { + "bbox": [ + 91, + 99, + 501, + 193 + ], + "spans": [ + { + "bbox": [ + 91, + 99, + 501, + 193 + ], + "type": "image", + "image_path": "7728a49709e41201261ada1ad4e63fa21cf7c8d4cf6c70b176d2fab65b966be8.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "lines": [ + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "spans": [ + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "text", + "content": "Figure 2 - Pipeline. Given an input image " + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "text", + "content": ", we first transform it to the canonical space using CSTM. The transformed image " + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "inline_equation", + "content": "I_{c}" + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "text", + "content": " is fed into a depth estimation model to produce the metric depth " + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "inline_equation", + "content": "D_{c}" + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "text", + "content": " in the canonical space. During training, " + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "inline_equation", + "content": "D_{c}" + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "text", + "content": " is supervised by a GT depth " + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "inline_equation", + "content": "D_{c}^{*}" + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "text", + "content": " which is also transformed into the canonical space. In inference, after producing the metric depth " + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "inline_equation", + "content": "D_{c}" + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "text", + "content": " in the canonical space, we perform a de-canonical transformation to convert it back to the space of the original input " + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 72, + 194, + 523, + 229 + ], + "type": "text", + "content": ". The canonical and de-canonical transformations are executed using camera intrinsics." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 71, + 237, + 142, + 312 + ], + "blocks": [ + { + "bbox": [ + 71, + 237, + 142, + 312 + ], + "lines": [ + { + "bbox": [ + 71, + 237, + 142, + 312 + ], + "spans": [ + { + "bbox": [ + 71, + 237, + 142, + 312 + ], + "type": "image", + "image_path": "f5d089fa78130278337e20475ace3f4ba63612965458690c503c830081e447c7.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 73, + 313, + 138, + 320 + ], + "lines": [ + { + "bbox": [ + 73, + 313, + 138, + 320 + ], + "spans": [ + { + "bbox": [ + 73, + 313, + 138, + 320 + ], + "type": "text", + "content": "focal=26mm,depth=2m" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 143, + 237, + 213, + 312 + ], + "blocks": [ + { + "bbox": [ + 143, + 237, + 213, + 312 + ], + "lines": [ + { + "bbox": [ + 143, + 237, + 213, + 312 + ], + "spans": [ + { + "bbox": [ + 143, + 237, + 213, + 312 + ], + "type": "image", + "image_path": "6e59db16f5bd876046238ea2174fc990347698e9ecc7020f5bf1573445e41404.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 146, + 313, + 209, + 320 + ], + "lines": [ + { + "bbox": [ + 146, + 313, + 209, + 320 + ], + "spans": [ + { + "bbox": [ + 146, + 313, + 209, + 320 + ], + "type": "text", + "content": "focal=52mm,depth=2m" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 213, + 237, + 285, + 312 + ], + "blocks": [ + { + "bbox": [ + 213, + 237, + 285, + 312 + ], + "lines": [ + { + "bbox": [ + 213, + 237, + 285, + 312 + ], + "spans": [ + { + "bbox": [ + 213, + 237, + 285, + 312 + ], + "type": "image", + "image_path": "71e22d2db032afff640b57fb43959242720d3a29b19ee73703aa642713f2dda8.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 217, + 313, + 282, + 320 + ], + "lines": [ + { + "bbox": [ + 217, + 313, + 282, + 320 + ], + "spans": [ + { + "bbox": [ + 217, + 313, + 282, + 320 + ], + "type": "text", + "content": "focal=26mm,depth=1m" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 72, + 323, + 285, + 358 + ], + "lines": [ + { + "bbox": [ + 72, + 323, + 285, + 358 + ], + "spans": [ + { + "bbox": [ + 72, + 323, + 285, + 358 + ], + "type": "text", + "content": "Figure 3 - Photos of a chair captured at different distances with different cameras. The first two photos are captured at the same distance but with different cameras, while the last one is taken at a closer distance with the same camera as the first one." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "bbox": [ + 69, + 362, + 288, + 384 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 362, + 288, + 384 + ], + "spans": [ + { + "bbox": [ + 69, + 362, + 288, + 384 + ], + "type": "text", + "content": "decouple the metric from the supervision and compromise learning the affine-invariant depth." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 69, + 384, + 288, + 417 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 384, + 288, + 417 + ], + "spans": [ + { + "bbox": [ + 69, + 384, + 288, + 417 + ], + "type": "text", + "content": "Fig. 4 (A) shows a simple pin-hole perspective projection. Object " + }, + { + "bbox": [ + 69, + 384, + 288, + 417 + ], + "type": "inline_equation", + "content": "A" + }, + { + "bbox": [ + 69, + 384, + 288, + 417 + ], + "type": "text", + "content": " locating at " + }, + { + "bbox": [ + 69, + 384, + 288, + 417 + ], + "type": "inline_equation", + "content": "d_{a}" + }, + { + "bbox": [ + 69, + 384, + 288, + 417 + ], + "type": "text", + "content": " is projected to " + }, + { + "bbox": [ + 69, + 384, + 288, + 417 + ], + "type": "inline_equation", + "content": "A^{\\prime}" + }, + { + "bbox": [ + 69, + 384, + 288, + 417 + ], + "type": "text", + "content": ". Based on the principle of similarity, we have the equation:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 138, + 423, + 288, + 447 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 138, + 423, + 288, + 447 + ], + "spans": [ + { + "bbox": [ + 138, + 423, + 288, + 447 + ], + "type": "interline_equation", + "content": "d _ {a} = \\hat {S} \\left[ \\frac {\\hat {f}}{\\hat {S} ^ {\\prime}} \\right] = \\hat {S} \\cdot \\alpha \\tag {1}", + "image_path": "265c876c33c28bc17ea221302c21b6186cdec564fb64bab1b4f9ebc855b7924c.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "spans": [ + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "inline_equation", + "content": "\\hat{S}" + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "inline_equation", + "content": "\\hat{S}^{\\prime}" + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "text", + "content": " are the real and imaging size respectively. " + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "inline_equation", + "content": "\\hat{\\tau}" + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "text", + "content": " denotes variables are in the physical metric (e.g., millimeter). To recover " + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "inline_equation", + "content": "d_{a}" + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "text", + "content": ", focal length, imaging size of the object, and real-world object size must be available. Estimating the focal length from a single image is a challenging and ill-posed problem. Although several methods [57, 16] have been explored, the accuracy is still far from being satisfactory. Here, we simplify the problem by assuming the focal length of a training/test image is available. Understanding the imaging size is much easier for a neural network. To obtain the real-world object size, a neural network needs to understand the semantic scene layout and the object, at which a neural network excels. We define " + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "inline_equation", + "content": "\\alpha = \\hat{f} / \\hat{s}^{\\prime}" + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "text", + "content": ", so " + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "inline_equation", + "content": "d_{a}" + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "text", + "content": " is proportional to " + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 68, + 445, + 288, + 598 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 69, + 599, + 289, + 620 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 599, + 289, + 620 + ], + "spans": [ + { + "bbox": [ + 69, + 599, + 289, + 620 + ], + "type": "text", + "content": "We make the following observations regarding sensor size, pixel size, and focal length." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 69, + 621, + 289, + 686 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 621, + 289, + 686 + ], + "spans": [ + { + "bbox": [ + 69, + 621, + 289, + 686 + ], + "type": "text", + "content": "O1: Sensor size and pixel size do not affect the metric depth estimation. Based on the perspective projection (Fig. 4 (A)), the sensor size only affects the field of view (FOV) and is irrelevant to " + }, + { + "bbox": [ + 69, + 621, + 289, + 686 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 69, + 621, + 289, + 686 + ], + "type": "text", + "content": ", thus does not affect the metric depth estimation. For the pixel size, we assume two cameras with different pixel sizes (" + }, + { + "bbox": [ + 69, + 621, + 289, + 686 + ], + "type": "inline_equation", + "content": "\\delta_{1} = 2\\delta_{2}" + }, + { + "bbox": [ + 69, + 621, + 289, + 686 + ], + "type": "text", + "content": ") but the same focal" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "spans": [ + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "text", + "content": "length " + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "inline_equation", + "content": "\\hat{f}" + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "text", + "content": " to capture the same object locating at " + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "inline_equation", + "content": "d_{a}" + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "text", + "content": ". Fig. 4 (B) shows their captured photos. According to the preliminaries, the pixel-represented focal length " + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "inline_equation", + "content": "f_{1} = \\frac{1}{2} f_{2}" + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "text", + "content": ". As the second camera has a smaller pixel size, although in the same projected imaging size " + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "inline_equation", + "content": "\\hat{S}'" + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "text", + "content": ", the pixel-represented image resolution is " + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "inline_equation", + "content": "S_1' = \\frac{1}{2} S_2'" + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "text", + "content": ". According to Eq. (1), " + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "inline_equation", + "content": "\\frac{\\hat{f}}{\\delta_1 \\cdot S_1'} = \\frac{\\hat{f}}{\\delta_2 \\cdot S_2'}" + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "text", + "content": ", i.e. " + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "inline_equation", + "content": "\\alpha_{1} = \\alpha_{2}" + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "text", + "content": ", so " + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "inline_equation", + "content": "d_{1} = d_{2}" + }, + { + "bbox": [ + 304, + 238, + 525, + 330 + ], + "type": "text", + "content": ". Therefore, different camera sensors would not affect the metric depth estimation." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 331, + 525, + 418 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 331, + 525, + 418 + ], + "spans": [ + { + "bbox": [ + 304, + 331, + 525, + 418 + ], + "type": "text", + "content": "O2: The focal length is vital for metric depth estimation. Fig. 3 shows the metric ambiguity issue caused by the unknown focal length. In Fig. 5, two cameras " + }, + { + "bbox": [ + 304, + 331, + 525, + 418 + ], + "type": "inline_equation", + "content": "(\\hat{f}_1 = 2\\hat{f}_2)" + }, + { + "bbox": [ + 304, + 331, + 525, + 418 + ], + "type": "text", + "content": " are at distances " + }, + { + "bbox": [ + 304, + 331, + 525, + 418 + ], + "type": "inline_equation", + "content": "d_{1}" + }, + { + "bbox": [ + 304, + 331, + 525, + 418 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 331, + 525, + 418 + ], + "type": "inline_equation", + "content": "d_{2}" + }, + { + "bbox": [ + 304, + 331, + 525, + 418 + ], + "type": "text", + "content": ", the imaging sizes on cameras are the same. Only from the appearance, the network will be confused when supervised with different labels. Based on this, we propose a canonical camera transformation method to solve the supervision and image appearance conflicts." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 426, + 477, + 437 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 426, + 477, + 437 + ], + "spans": [ + { + "bbox": [ + 306, + 426, + 477, + 437 + ], + "type": "text", + "content": "3.2. Canonical Camera Transformation" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 444, + 525, + 509 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 444, + 525, + 509 + ], + "spans": [ + { + "bbox": [ + 305, + 444, + 525, + 509 + ], + "type": "text", + "content": "The core idea is to set up a canonical camera space " + }, + { + "bbox": [ + 305, + 444, + 525, + 509 + ], + "type": "inline_equation", + "content": "((f_x^c, f_y^c), f_x^c = f_y^c = f^c" + }, + { + "bbox": [ + 305, + 444, + 525, + 509 + ], + "type": "text", + "content": " in experiments) and transform all training data to this space. Consequently, all data can roughly be regarded as captured by the canonical camera. We propose two transformation methods, i.e. either on the input image " + }, + { + "bbox": [ + 305, + 444, + 525, + 509 + ], + "type": "inline_equation", + "content": "(\\mathbf{I} \\in \\mathbb{R}^{H \\times W \\times 3})" + }, + { + "bbox": [ + 305, + 444, + 525, + 509 + ], + "type": "text", + "content": " or the GT label " + }, + { + "bbox": [ + 305, + 444, + 525, + 509 + ], + "type": "inline_equation", + "content": "(\\mathbf{D} \\in \\mathbb{R}^{H \\times W})" + }, + { + "bbox": [ + 305, + 444, + 525, + 509 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 313, + 509, + 403, + 567 + ], + "blocks": [ + { + "bbox": [ + 313, + 509, + 403, + 567 + ], + "lines": [ + { + "bbox": [ + 313, + 509, + 403, + 567 + ], + "spans": [ + { + "bbox": [ + 313, + 509, + 403, + 567 + ], + "type": "image", + "image_path": "ae32257d9e147b759fbfdcb3d01909c276e77aa6107e29be49a9cc992a4135e5.jpg" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_body" + } + ], + "index": 19 + }, + { + "type": "image", + "bbox": [ + 403, + 509, + 518, + 567 + ], + "blocks": [ + { + "bbox": [ + 403, + 509, + 518, + 567 + ], + "lines": [ + { + "bbox": [ + 403, + 509, + 518, + 567 + ], + "spans": [ + { + "bbox": [ + 403, + 509, + 518, + 567 + ], + "type": "image", + "image_path": "213abb90bd8d03fb56bbbd45bc9fd6ee300fff5c4a8d2efd313822101c308d31.jpg" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_body" + } + ], + "index": 20 + }, + { + "type": "image", + "bbox": [ + 312, + 616, + 520, + 666 + ], + "blocks": [ + { + "bbox": [ + 309, + 574, + 522, + 610 + ], + "lines": [ + { + "bbox": [ + 309, + 574, + 522, + 610 + ], + "spans": [ + { + "bbox": [ + 309, + 574, + 522, + 610 + ], + "type": "text", + "content": "Figure 4 - Pinhole camera model. (A) Object " + }, + { + "bbox": [ + 309, + 574, + 522, + 610 + ], + "type": "inline_equation", + "content": "A" + }, + { + "bbox": [ + 309, + 574, + 522, + 610 + ], + "type": "text", + "content": " at the distance " + }, + { + "bbox": [ + 309, + 574, + 522, + 610 + ], + "type": "inline_equation", + "content": "d_{a}" + }, + { + "bbox": [ + 309, + 574, + 522, + 610 + ], + "type": "text", + "content": " is projected to the image plane. (B) Using two cameras to capture the car. The left one has a larger pixel size. Although the projected imaging sizes are the same, the pixel-represented images (resolution) are different." + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 312, + 616, + 520, + 666 + ], + "lines": [ + { + "bbox": [ + 312, + 616, + 520, + 666 + ], + "spans": [ + { + "bbox": [ + 312, + 616, + 520, + 666 + ], + "type": "image", + "image_path": "fee3c55f6187142e4df0d5adffd27dc7939de79dd4b583d1693e55caf2483918.jpg" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 309, + 673, + 522, + 702 + ], + "lines": [ + { + "bbox": [ + 309, + 673, + 522, + 702 + ], + "spans": [ + { + "bbox": [ + 309, + 673, + 522, + 702 + ], + "type": "text", + "content": "Figure 5 - Illustration of two cameras with different focal length at different distance. As " + }, + { + "bbox": [ + 309, + 673, + 522, + 702 + ], + "type": "inline_equation", + "content": "f_{1} = 2f_{2}" + }, + { + "bbox": [ + 309, + 673, + 522, + 702 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 309, + 673, + 522, + 702 + ], + "type": "inline_equation", + "content": "d_{1} = 2d_{2}" + }, + { + "bbox": [ + 309, + 673, + 522, + 702 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 309, + 673, + 522, + 702 + ], + "type": "inline_equation", + "content": "A" + }, + { + "bbox": [ + 309, + 673, + 522, + 702 + ], + "type": "text", + "content": " is projected to two image planes with the same imaging size (i.e. " + }, + { + "bbox": [ + 309, + 673, + 522, + 702 + ], + "type": "inline_equation", + "content": "A_{1}' = A_{2}'" + }, + { + "bbox": [ + 309, + 673, + 522, + 702 + ], + "type": "text", + "content": ")." + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_caption" + } + ], + "index": 22 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "spans": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "text", + "content": "9046" + } + ] + } + ], + "index": 24 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 69, + 99, + 211, + 110 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 99, + 211, + 110 + ], + "spans": [ + { + "bbox": [ + 69, + 99, + 211, + 110 + ], + "type": "text", + "content": "The original intrinsics are " + }, + { + "bbox": [ + 69, + 99, + 211, + 110 + ], + "type": "inline_equation", + "content": "\\{f, u_0, v_0\\}" + }, + { + "bbox": [ + 69, + 99, + 211, + 110 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "spans": [ + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "text", + "content": "Method1: transforming depth labels (CSTM_label). Fig. 3's ambiguity is for depths. Thus our first method directly transforms the ground-truth depth labels to solve this problem. Specifically, we scale the ground-truth depth " + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "inline_equation", + "content": "(\\mathbf{D}^{*})" + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "text", + "content": " with the ratio " + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "inline_equation", + "content": "\\omega_{d} = \\frac{f^{c}}{f}" + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "text", + "content": " in training, i.e., " + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "inline_equation", + "content": "\\mathbf{D}_c^* = \\omega_d\\mathbf{D}^*" + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "text", + "content": ". The original camera model is transformed to " + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "inline_equation", + "content": "\\{f^c,u_0,v_0\\}" + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "text", + "content": ". In inference, the predicted depth " + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "inline_equation", + "content": "(\\mathbf{D}_c)" + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "text", + "content": " is in the canonical space and needs to perform a de-canonical transformation to recover the metric information, i.e., " + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "inline_equation", + "content": "\\mathbf{D} = \\frac{1}{\\omega_d}\\mathbf{D}_c" + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "text", + "content": ". Note the input " + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "inline_equation", + "content": "\\mathbf{I}" + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "text", + "content": " does not perform any transformation, i.e., " + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_c = \\mathbf{I}" + }, + { + "bbox": [ + 68, + 111, + 289, + 222 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "spans": [ + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "text", + "content": "Method2: transforming input images (CSTM_image). From another view, the ambiguity is caused by the similar image appearance. Thus this method is to transform the input image to simulate the canonical camera imaging effect. Specifically, the image " + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "inline_equation", + "content": "\\mathbf{I}" + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "text", + "content": " is resized with the ratio " + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "inline_equation", + "content": "\\omega_{r} = \\frac{f^{c}}{f}" + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "text", + "content": ", i.e., " + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_c = \\mathfrak{T}(\\mathbf{I},\\omega_r)" + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "text", + "content": ", where " + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "inline_equation", + "content": "\\mathfrak{T}(\\cdot)" + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "text", + "content": " denotes image resize. The optical center is resized, thus the canonical camera model is " + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "inline_equation", + "content": "\\{f^c,\\omega_ru_0,\\omega_rv_0\\}" + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "text", + "content": ". The ground-truth labels are resized without any scaling, i.e., " + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "inline_equation", + "content": "\\mathbf{D}_c^* = \\mathfrak{T}(\\mathbf{D}^*,\\omega_r)" + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "text", + "content": ". In inference, the de-canonical transformation is to resize the prediction to the original size without scaling, i.e., " + }, + { + "bbox": [ + 68, + 223, + 289, + 345 + ], + "type": "inline_equation", + "content": "\\mathbf{D} = \\mathfrak{T}(\\mathbf{D}_c,\\frac{1}{\\omega_r})" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 68, + 346, + 289, + 425 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 346, + 289, + 425 + ], + "spans": [ + { + "bbox": [ + 68, + 346, + 289, + 425 + ], + "type": "text", + "content": "Fig. 2 shows the pipeline. After performing either transformation, we randomly crop a patch for training. The cropping only adjusts the FOV and the optical center, thus not causing any metric ambiguity issues. In the labels transformation method " + }, + { + "bbox": [ + 68, + 346, + 289, + 425 + ], + "type": "inline_equation", + "content": "\\omega_{r} = 1" + }, + { + "bbox": [ + 68, + 346, + 289, + 425 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 68, + 346, + 289, + 425 + ], + "type": "inline_equation", + "content": "\\omega_{d} = \\frac{f^{c}}{f}" + }, + { + "bbox": [ + 68, + 346, + 289, + 425 + ], + "type": "text", + "content": ", while " + }, + { + "bbox": [ + 68, + 346, + 289, + 425 + ], + "type": "inline_equation", + "content": "\\omega_{d} = 1" + }, + { + "bbox": [ + 68, + 346, + 289, + 425 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 68, + 346, + 289, + 425 + ], + "type": "inline_equation", + "content": "\\omega_{r} = \\frac{f^{c}}{f}" + }, + { + "bbox": [ + 68, + 346, + 289, + 425 + ], + "type": "text", + "content": " in the images transformation method. The training objective is as follows:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 137, + 435, + 288, + 451 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 137, + 435, + 288, + 451 + ], + "spans": [ + { + "bbox": [ + 137, + 435, + 288, + 451 + ], + "type": "interline_equation", + "content": "\\min _ {\\theta} \\left| \\mathfrak {N} _ {d} \\left(\\mathbf {I} _ {c}, \\theta\\right) - \\mathbf {D} _ {c} ^ {*} \\right| \\tag {2}", + "image_path": "bdf81c390d332ce8e5e49ccb3833c6a0e53383c13be003235518104017cbc49a.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 68, + 456, + 289, + 478 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 456, + 289, + 478 + ], + "spans": [ + { + "bbox": [ + 68, + 456, + 289, + 478 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 68, + 456, + 289, + 478 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 68, + 456, + 289, + 478 + ], + "type": "text", + "content": " is the network's " + }, + { + "bbox": [ + 68, + 456, + 289, + 478 + ], + "type": "inline_equation", + "content": "(\\mathcal{N}_d(\\cdot))" + }, + { + "bbox": [ + 68, + 456, + 289, + 478 + ], + "type": "text", + "content": " parameters, " + }, + { + "bbox": [ + 68, + 456, + 289, + 478 + ], + "type": "inline_equation", + "content": "\\mathbf{D}_c^*" + }, + { + "bbox": [ + 68, + 456, + 289, + 478 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 68, + 456, + 289, + 478 + ], + "type": "inline_equation", + "content": "\\mathbf{I}_c" + }, + { + "bbox": [ + 68, + 456, + 289, + 478 + ], + "type": "text", + "content": " are transformed ground-truth depth labels and images." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 68, + 479, + 289, + 621 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 479, + 289, + 621 + ], + "spans": [ + { + "bbox": [ + 68, + 479, + 289, + 621 + ], + "type": "text", + "content": "Supervision. To further boost the performance, we propose a random proposal normalization loss (RPNL). The scale-shift invariant loss [32, 57] is widely applied for the affine-invariant depth estimation, which decouples the depth scale to emphasize the single image distribution. However, such normalization based on the whole image inevitably squeezes the fine-grained depth difference, particularly in close regions. Inspired by this, we propose to randomly crop several patches " + }, + { + "bbox": [ + 68, + 479, + 289, + 621 + ], + "type": "inline_equation", + "content": "(p_{i(i = 0,\\dots,M)}\\in \\mathbb{R}^{h_i\\times w_i})" + }, + { + "bbox": [ + 68, + 479, + 289, + 621 + ], + "type": "text", + "content": " from the ground truth " + }, + { + "bbox": [ + 68, + 479, + 289, + 621 + ], + "type": "inline_equation", + "content": "\\mathbf{D}_c^*" + }, + { + "bbox": [ + 68, + 479, + 289, + 621 + ], + "type": "text", + "content": " and the predicted depth " + }, + { + "bbox": [ + 68, + 479, + 289, + 621 + ], + "type": "inline_equation", + "content": "\\mathbf{D}_c" + }, + { + "bbox": [ + 68, + 479, + 289, + 621 + ], + "type": "text", + "content": ". Then we employ the median absolute deviation normalization [40] for paired patches. By normalizing the local statistics, we can enhance local contrast. The loss function is as follows:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 71, + 629, + 288, + 689 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 629, + 288, + 689 + ], + "spans": [ + { + "bbox": [ + 71, + 629, + 288, + 689 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} L _ {\\mathrm {R P N L}} = \\frac {1}{M N} \\sum_ {p _ {i}} ^ {M} \\sum_ {j} ^ {N} \\left| \\frac {d _ {p _ {i} , j} ^ {*} - \\mu \\left(d _ {p _ {i} , j} ^ {*}\\right)}{\\frac {1}{N} \\sum_ {j} ^ {N} \\left| d _ {p _ {i} , j} ^ {*} - \\mu \\left(d _ {p _ {i} , j} ^ {*}\\right) \\right|} - \\right. \\\\ \\frac {d _ {p _ {i , j}} - \\mu \\left(d _ {p _ {i , j}}\\right)}{\\frac {1}{N} \\sum_ {j} ^ {N} \\left| d _ {p _ {i , j}} - \\mu \\left(d _ {p _ {i , j}}\\right) \\right|} \\tag {3} \\\\ \\end{array}", + "image_path": "f2b5988468a191c83903850fc0597e9da27188757adc877170cbc60a805c65e7.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "spans": [ + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "inline_equation", + "content": "d^{*}\\in \\mathbf{D}_{c}^{*}" + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "inline_equation", + "content": "d\\in \\mathbf{D}_c" + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "text", + "content": " are the ground truth and predicted depth respectively. " + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "inline_equation", + "content": "\\mu (\\cdot)" + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "text", + "content": " and is the median of depth. " + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "text", + "content": " is the number of proposal crops, which is set to 32. During training, proposals are randomly cropped from the image by 0.125 to 0.5 of the original size. Furthermore, several other losses are employed, including the scale-invariant logarithmic loss [10] " + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "inline_equation", + "content": "L_{silog}" + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "text", + "content": ", pair-wise normal regression loss [57] " + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{PWN}}" + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "text", + "content": ", virtual normal loss [53] " + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{VNL}}" + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "text", + "content": ". Note " + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "inline_equation", + "content": "L_{silog}" + }, + { + "bbox": [ + 306, + 99, + 526, + 198 + ], + "type": "text", + "content": " is a variant of L1 loss. The overall losses are as follows." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 330, + 207, + 482, + 220 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 330, + 207, + 482, + 220 + ], + "spans": [ + { + "bbox": [ + 330, + 207, + 482, + 220 + ], + "type": "interline_equation", + "content": "L = L _ {\\mathrm {P W N}} + L _ {\\mathrm {V N L}} + L _ {\\text {s i l o g}} + L _ {\\mathrm {R P N L}}.", + "image_path": "f30feba521ead92c7e6d3a04eca569d01d6b2f1a7136c9430566bcfc5dab7fc7.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 230, + 380, + 243 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 230, + 380, + 243 + ], + "spans": [ + { + "bbox": [ + 306, + 230, + 380, + 243 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 248, + 525, + 325 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 248, + 525, + 325 + ], + "spans": [ + { + "bbox": [ + 305, + 248, + 525, + 325 + ], + "type": "text", + "content": "Dataset details. We collect 11 public RGB-D datasets, and over 8 million data for training. It spreads over diverse indoor and outdoor scenes. Note that all datasets have provided camera intrinsic parameters. Over 10K different cameras are included. Furthermore, we collect 7 unseen datasets for robustness and generalization evaluation. Details of employed data are reported in the supplementary materials." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 325, + 526, + 467 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 325, + 526, + 467 + ], + "spans": [ + { + "bbox": [ + 305, + 325, + 526, + 467 + ], + "type": "text", + "content": "Implementation details. We use an UNet architecture with the ConvNext-large [26] backbone. ImageNet-22K pretrained weights are used for initialization. We use AdamW with a batch size of 192, an initial learning rate 0.0001 for all layers, and the polynomial decaying method with the power of 0.9. We use 48 A100 GPUs and train for 500K iterations. Following [53], we balance all datasets in a mini-batch to ensure each dataset accounts for an almost equal ratio. In training, images are processed by the LSTM, flipped horizontally with a " + }, + { + "bbox": [ + 305, + 325, + 526, + 467 + ], + "type": "inline_equation", + "content": "50\\%" + }, + { + "bbox": [ + 305, + 325, + 526, + 467 + ], + "type": "text", + "content": " chance, and then randomly cropped into " + }, + { + "bbox": [ + 305, + 325, + 526, + 467 + ], + "type": "inline_equation", + "content": "512 \\times 960" + }, + { + "bbox": [ + 305, + 325, + 526, + 467 + ], + "type": "text", + "content": ". In ablation studies, training settings are different as we sample 5000 images from each dataset for training and train on 8 GPUs for 150K iterations." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 468, + 526, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 468, + 526, + 687 + ], + "spans": [ + { + "bbox": [ + 305, + 468, + 526, + 687 + ], + "type": "text", + "content": "Evaluation details. a) To show the robustness of our metric depth estimation method, we test on 8 zero-shot benchmarks, including NYUv2 [39], KITTI [12], NuScenes [4], 7-scenes [38], iBIMS-1 [19], DIODE [45], ETH3D [37]. Absolute relative error (AbsRel), the accuracy under threshold " + }, + { + "bbox": [ + 305, + 468, + 526, + 687 + ], + "type": "inline_equation", + "content": "(\\delta_i < 1.25^i, i = 1,2,3)" + }, + { + "bbox": [ + 305, + 468, + 526, + 687 + ], + "type": "text", + "content": ", root mean squared error (RMS), root mean squared error in log space (RMS_log), and log10 error (log10) metrics are employed. b) Furthermore, we also follow current affine-invariant depth benchmarks [57, 60] (Tab. 4) to evaluate the generalization ability on 5 zero-shot datasets, i.e., NYUv2, DIODE, ETH3D, ScanNet [7], and KITTI. We mainly compare with large-scale data trained models. Note that in this benchmark we follow existing methods to apply the scale shift alignment before evaluation. c) To evaluate our metric 3D reconstruction quality, we randomly sample 9 unseen scenes from NYUv2 and use colmap [36] to obtain the camera poses for multi-frame reconstruction. Chamfer " + }, + { + "bbox": [ + 305, + 468, + 526, + 687 + ], + "type": "inline_equation", + "content": "l_{1}" + }, + { + "bbox": [ + 305, + 468, + 526, + 687 + ], + "type": "text", + "content": " distance and the F-score [18] are used to evaluate the reconstruction accuracy. d) In dense-SLAM experiments, following Li et al. [24], we" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "spans": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "text", + "content": "9047" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 72, + 125, + 290, + 272 + ], + "blocks": [ + { + "bbox": [ + 72, + 98, + 286, + 124 + ], + "lines": [ + { + "bbox": [ + 72, + 98, + 286, + 124 + ], + "spans": [ + { + "bbox": [ + 72, + 98, + 286, + 124 + ], + "type": "text", + "content": "Table 1 - Quantitative comparison on NYUv2 and KITTI benchmarks. Both datasets are unseen to our model, but we can achieve comparable performance with state-of-the-art methods." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 72, + 125, + 290, + 272 + ], + "lines": [ + { + "bbox": [ + 72, + 125, + 290, + 272 + ], + "spans": [ + { + "bbox": [ + 72, + 125, + 290, + 272 + ], + "type": "table", + "html": "
NYUv2 Benchmark
Methodδ1↑δ2↑δ3↑AbsRel↓log10↓RMS↓
Li et al. [23]0.7880.9580.9910.1430.0630.635
Laina et al. [21]0.8110.9530.9880.1270.0550.573
VNL [55]0.8750.9760.9940.1080.0480.416
TrDepth [52]0.9000.9830.9960.1060.0450.365
Adabins [2]0.9030.9840.9970.1030.0440.364
NeWCRFs [59]0.9220.9920.9980.0950.0410.334
Ours LSTM_image0.9250.9830.9940.0920.0400.341
Ours LSTM_label0.9440.9860.9950.0830.0350.310
KITTI Benchmark
Methodδ1↑δ2↑δ3↑AbsRel↓RMS↓RMS_log↓
Guo et al. [14]0.9020.9690.9860.0903.2580.168
VNL [55]0.9380.9900.9980.0723.2580.117
TrDepth [52]0.9560.9940.9990.0642.7550.098
Adabins [2]0.9640.9950.9990.0582.3600.088
NeWCRFs [59]0.9740.9970.9990.0522.1290.079
Ours LSTM_image0.9670.9950.9990.0602.8430.087
Ours LSTM_label0.9640.9930.9980.0582.7700.092
", + "image_path": "2c0b3a6538b795893f82901077e11d2364e5fa61f1101d03e5475df7c882d83d.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 69, + 284, + 289, + 318 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 284, + 289, + 318 + ], + "spans": [ + { + "bbox": [ + 69, + 284, + 289, + 318 + ], + "type": "text", + "content": "test on the KITTI odometry benchmark [12] and evaluate the average translational RMS drift " + }, + { + "bbox": [ + 69, + 284, + 289, + 318 + ], + "type": "inline_equation", + "content": "(\\% ,t_{rel})" + }, + { + "bbox": [ + 69, + 284, + 289, + 318 + ], + "type": "text", + "content": " and rotational RMS drift " + }, + { + "bbox": [ + 69, + 284, + 289, + 318 + ], + "type": "inline_equation", + "content": "(^{\\circ} / 100m,r_{rel})" + }, + { + "bbox": [ + 69, + 284, + 289, + 318 + ], + "type": "text", + "content": " errors [12]." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 69, + 338, + 217, + 348 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 338, + 217, + 348 + ], + "spans": [ + { + "bbox": [ + 69, + 338, + 217, + 348 + ], + "type": "text", + "content": "4.1. Zero-shot Generalization Test" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 68, + 359, + 289, + 448 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 359, + 289, + 448 + ], + "spans": [ + { + "bbox": [ + 68, + 359, + 289, + 448 + ], + "type": "text", + "content": "Evaluation on metric depth benchmarks. To evaluate the accuracy of predicted metric depth, firstly, we compare with state-of-the-art (SOTA) metric depth prediction methods on NYUv2 [39], KITTI [13]. We use the same model to do all evaluations. Results are reported in Tab. 1. Without any fine-tuning or metric adjustment, we can achieve comparable performance with SOTA methods, which are trained on benchmarks for hundreds of epochs." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 68, + 452, + 288, + 571 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 452, + 288, + 571 + ], + "spans": [ + { + "bbox": [ + 68, + 452, + 288, + 571 + ], + "type": "text", + "content": "Furthermore, we collect 6 unseen datasets to do more metric accuracy evaluation. These datasets contain a wide range of indoor and outdoor scenes. The camera models are also various, e.g. 7scenes has a short focal length (around 500), while ETH3D is 2000. We compare with the SOTA metric depth estimation methods and take their NYUv2 and KITTI models for indoor and outdoor scenes evaluation respectively. In Tab. 3, although 7Scenes is similar to NYUv2 and NuScenes is similar to KITTI, existing methods face a noticeable performance decrease. In contrast, our model is more robust." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 68, + 577, + 289, + 686 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 68, + 577, + 289, + 686 + ], + "spans": [ + { + "bbox": [ + 68, + 577, + 289, + 686 + ], + "type": "text", + "content": "Generalization over diverse scenes. Affine-invariant depth benchmarks decouple the scale's effect, which aims to evaluate the model's generalization ability to diverse scenes. Recent impact works, such as MiDaS, LeReS, and DPT, achieved promising performance on them. Following them, we test on 5 datasets and manually align the scale and shift to the ground-truth depth before evaluation. Results are reported in Tab. 4. Although our method enforces the network to recover more challenging metric information, our method outperforms them by a large margin on most datasets." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 99, + 478, + 110 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 99, + 478, + 110 + ], + "spans": [ + { + "bbox": [ + 306, + 99, + 478, + 110 + ], + "type": "text", + "content": "4.2. Applications Based on Our Method" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 116, + 526, + 324 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 116, + 526, + 324 + ], + "spans": [ + { + "bbox": [ + 304, + 116, + 526, + 324 + ], + "type": "text", + "content": "3D scene reconstruction. To demonstrate our work can recover the 3D metric shape in the wild, we first do the quantitative comparison on 9 NYUv2 scenes, which are unseen during training. We predict the per-frame metric depth and then fuse them together with provided camera poses. Results are reported in Tab. 2. We compare with the video consistent depth prediction method (RCVD [20]), the unsupervised video depth estimation method (SC-DepthV2 [3]), the 3D scene shape recovery method (LeReS [57]), affine-invariant depth estimation method (DPT [31]), and the multi-view stereo reconstruction method (DPSNet [17]). Apart from DPSNet and our method, other methods have to align the scale with the ground truth depth for each frame. Although our method does not aim for the video or multi-view reconstruction problem, our method can achieve promising consistency between frames and reconstruct much more accurate 3D scenes than others on these zero-shot scenes. From the qualitative comparison in Fig. 6, our reconstructions have much less noise and outliers." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 324, + 526, + 510 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 324, + 526, + 510 + ], + "spans": [ + { + "bbox": [ + 304, + 324, + 526, + 510 + ], + "type": "text", + "content": "Dense-SLAM mapping. Monocular SLAM is an important robotics application. It takes a monocular video input to create the trajectory and dense 3D mapping. Owing to limited photometric and geometric constraints, existing methods face serious scale drift problems in large scenes and cannot recover the metric information. Our robust metric depth estimation method is a strong depth prior to the SLAM system. To demonstrate this benefit, we naively input our metric depth to the SOTA SLAM system, Droid-SLAM [44], and evaluate the trajectory on KITTI. We do not do any tuning on the original system. Trajectory comparisons are reported in Tab. 5. As Droid-SLAM can access accurate per-frame metric depth, like an RGB-D SLAM, the translation drift " + }, + { + "bbox": [ + 304, + 324, + 526, + 510 + ], + "type": "inline_equation", + "content": "(t_{rel})" + }, + { + "bbox": [ + 304, + 324, + 526, + 510 + ], + "type": "text", + "content": " decreases significantly. Furthermore, with our depths, Droid-SLAM can perform denser and more accurate 3D mapping. An example is shown in Fig. 1 and more cases are shown in the supplementary materials." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 510, + 526, + 598 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 510, + 526, + 598 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 526, + 598 + ], + "type": "text", + "content": "Metrology in the wild. To show the robustness and accuracy of our recovered metric 3D, we download Flickr photos captured by various cameras and collect coarse camera intrinsic parameters from their metadata. We use our CSTM_image model to reconstruct their metric shape and measure structures' sizes (marked in red in Fig. 7), while the ground-truth sizes are in blue. It shows that our measured sizes are very close to the ground-truth sizes." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 604, + 391, + 616 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 604, + 391, + 616 + ], + "spans": [ + { + "bbox": [ + 306, + 604, + 391, + 616 + ], + "type": "text", + "content": "4.3. Ablation Study" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 620, + 526, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 620, + 526, + 687 + ], + "spans": [ + { + "bbox": [ + 304, + 620, + 526, + 687 + ], + "type": "text", + "content": "Ablation on canonical transformation. We study the effect of our proposed canonical transformation for the input images ('CSTM_input') and the canonical transformation for the ground-truth labels ('CSTM_output'). Results are reported in Tab. 6. We train the model on sampled mixed data (55K images) and test it on 6 datasets. A naive base" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "spans": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "text", + "content": "9048" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 73, + 125, + 520, + 198 + ], + "blocks": [ + { + "bbox": [ + 72, + 98, + 522, + 124 + ], + "lines": [ + { + "bbox": [ + 72, + 98, + 522, + 124 + ], + "spans": [ + { + "bbox": [ + 72, + 98, + 522, + 124 + ], + "type": "text", + "content": "Table 2 - Quantitative comparison of 3D scene reconstruction with LeReS [57], DPT [31], RCVD [20], SC-DepthV2 [3], and a learning-based MVS method (DPSNet [17]) on 9 unseen NYUv2 scenes. Apart from DPSNet and ours, other methods have to align the scale with ground truth depth for each frame. As a result, our reconstructed 3D scenes achieve the best performance." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 73, + 125, + 520, + 198 + ], + "lines": [ + { + "bbox": [ + 73, + 125, + 520, + 198 + ], + "spans": [ + { + "bbox": [ + 73, + 125, + 520, + 198 + ], + "type": "table", + "html": "
MethodBasement_0001aBedroom_0015Dining_room_0004Kitchen_0008Classroom_0004Playroom_0002Office_0024Office_0004Dining_room_0033
C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑C-l1↓F-score ↑
RCVD [20]0.3640.2760.0740.5820.4620.2510.0530.6200.1870.3270.7910.1870.3240.2410.6460.2170.4450.253
SC-DepthV2 [3]0.2540.2750.0640.5470.7490.2290.0490.6240.1670.2670.4260.2630.4820.1380.5160.2440.3560.247
DPSNet [17]0.2430.2990.1950.2760.9950.1860.2690.2030.2960.1950.1410.4850.1990.3620.2100.4620.2220.493
DPT [57]0.6980.2510.2890.2260.3960.3640.1260.3880.7800.1930.6050.2690.4540.2450.3640.2790.7510.185
LeReS [57]0.0810.5550.0640.6160.2780.4270.1470.2890.1430.4800.1450.5030.4080.1760.0960.4970.2410.325
Ours0.0420.7360.0590.6100.1590.4850.0500.6450.1450.4450.0360.8140.0690.6380.0450.7000.0600.663
", + "image_path": "2fe9f6e8cc56acebb0e3a9ef6f523345e741c258658d349adba40a4e976890f8.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 88, + 208, + 504, + 270 + ], + "blocks": [ + { + "bbox": [ + 88, + 208, + 504, + 270 + ], + "lines": [ + { + "bbox": [ + 88, + 208, + 504, + 270 + ], + "spans": [ + { + "bbox": [ + 88, + 208, + 504, + 270 + ], + "type": "image", + "image_path": "4b56032377236421e63e29a801ac64b51cb28f90ada88d91e80ea778868ec6ba.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 88, + 270, + 504, + 327 + ], + "blocks": [ + { + "bbox": [ + 88, + 270, + 504, + 327 + ], + "lines": [ + { + "bbox": [ + 88, + 270, + 504, + 327 + ], + "spans": [ + { + "bbox": [ + 88, + 270, + 504, + 327 + ], + "type": "image", + "image_path": "be704abe952894c6b599b1ebf742a1181d88cb9052b8cdf52b3f477a266eabd7.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 88, + 327, + 504, + 388 + ], + "blocks": [ + { + "bbox": [ + 88, + 327, + 504, + 388 + ], + "lines": [ + { + "bbox": [ + 88, + 327, + 504, + 388 + ], + "spans": [ + { + "bbox": [ + 88, + 327, + 504, + 388 + ], + "type": "image", + "image_path": "248f8285bdcd75d34422951ecac8f47d7ddb90f03201e31939368693fc5a7794.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 88, + 388, + 504, + 446 + ], + "blocks": [ + { + "bbox": [ + 88, + 388, + 504, + 446 + ], + "lines": [ + { + "bbox": [ + 88, + 388, + 504, + 446 + ], + "spans": [ + { + "bbox": [ + 88, + 388, + 504, + 446 + ], + "type": "image", + "image_path": "c476038b4bc54ed56dbb362a7eb7aa27a0d178c4bd5df24c00362b2acd29e16e.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 72, + 446, + 522, + 473 + ], + "lines": [ + { + "bbox": [ + 72, + 446, + 522, + 473 + ], + "spans": [ + { + "bbox": [ + 72, + 446, + 522, + 473 + ], + "type": "text", + "content": "Figure 6 - Reconstruction of zero-shot scenes with multiple views. We sample several NYUv2 scenes for 3D reconstruction comparison. As our method can predict accurate metric depth, thus all predictions are fused together for scene reconstruction. By contrast, LeReS [57]'s depth is up to an unknown scale and shift, which causes noticeable distortions. DPSNet [17] is a multi-view stereo method, which cannot work well on low-texture regions." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 70, + 482, + 298, + 628 + ], + "blocks": [ + { + "bbox": [ + 70, + 482, + 298, + 628 + ], + "lines": [ + { + "bbox": [ + 70, + 482, + 298, + 628 + ], + "spans": [ + { + "bbox": [ + 70, + 482, + 298, + 628 + ], + "type": "image", + "image_path": "49948a8e4b0e06a210056b0a94bbeaa9a5c8a3b86022e55370cb41b602d08e82.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 72, + 631, + 285, + 666 + ], + "lines": [ + { + "bbox": [ + 72, + 631, + 285, + 666 + ], + "spans": [ + { + "bbox": [ + 72, + 631, + 285, + 666 + ], + "type": "text", + "content": "Figure 7 - Reconstruction of in-the-wild scenes. We collect several Flickr photos, which are captured by various cameras. With photos' metadata, we reconstruct the 3D metric shape and measure structures' sizes. Red and blue marks are ours and ground-truth sizes respectively." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 483, + 526, + 680 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 483, + 526, + 680 + ], + "spans": [ + { + "bbox": [ + 306, + 483, + 526, + 680 + ], + "type": "text", + "content": "line ('Ours w/o LSTM') is to remove LSTM modules and enforce the same supervision as ours. Without LSTM, the model is unable to converge when training on mixed metric datasets and lost the metric prediction ability on zero-shot datasets. This is why mixed-data training methods compromise learning the affine-invariant depth to avoid metric issues. In contrast, our LSTM methods can enable the model to achieve the metric prediction ability, and they can achieve comparable performance. Tab. 1 also shows comparable performance. Therefore, both adjusting the supervision and the input image appearance during training can solve the metric ambiguity issues. Furthermore, we compare with CamConvs [11], which encodes the camera model in the decoder with a 4-channel feature. It employs the same training schedule, model, and training data as ours. This method enforces the network to implicitly understand various camera models from the image appearance and then bridges the imaging size to the real-world size. We believe that this" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "spans": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "text", + "content": "9049" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 101, + 116, + 491, + 175 + ], + "blocks": [ + { + "bbox": [ + 73, + 98, + 522, + 115 + ], + "lines": [ + { + "bbox": [ + 73, + 98, + 522, + 115 + ], + "spans": [ + { + "bbox": [ + 73, + 98, + 522, + 115 + ], + "type": "text", + "content": "Table 3 - Quantitative comparison with SOTA metric depth methods on 6 unseen benchmarks. For SOTA methods, we use their NYUv2 and KITTI models for indoor and outdoor scenes evaluation respectively, while we use the same model for all zero-shot testing." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 101, + 116, + 491, + 175 + ], + "lines": [ + { + "bbox": [ + 101, + 116, + 491, + 175 + ], + "spans": [ + { + "bbox": [ + 101, + 116, + 491, + 175 + ], + "type": "table", + "html": "
MethodDIODE(Indoor) Indoor scenes (AbsRel↓/RMS↓)DIODE(Outdoor) Outdoor scenes (AbsRel↓/RMS↓)
Adabins [2]0.443 / 1.9630.212 / 0.9010.218 / 0.4280.865 / 10.351.271 / 6.1780.445 / 10.658
NewCRFs [59]0.404 / 1.8670.206 / 0.8610.240 / 0.4510.854 / 9.2280.890 / 5.0110.400 / 12.139
Ours_CSTM_label0.252 / 1.4400.160 / 0.5210.183 / 0.3630.414 / 6.9340.416 / 3.0170.154 / 7.097
Ours_CSTM_image0.268 / 1.4290.144 / 0.6460.189 / 0.3880.535 / 6.5070.342 / 2.9650.147 / 5.889
", + "image_path": "1ba51a9a352893406fb8afc0021a6494bf7b6181a40f41d19cf17a7ef3ca19e1.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "type": "table", + "bbox": [ + 104, + 196, + 491, + 282 + ], + "blocks": [ + { + "bbox": [ + 73, + 177, + 522, + 195 + ], + "lines": [ + { + "bbox": [ + 73, + 177, + 522, + 195 + ], + "spans": [ + { + "bbox": [ + 73, + 177, + 522, + 195 + ], + "type": "text", + "content": "Table 4 - Comparison with SOTA affine-invariant depth methods on 5 zero-shot transfer benchmarks. Our model significantly outperforms previous methods and sets new state-of-the-art. Following the benchmark setting, all methods have manually aligned the scale and shift." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 104, + 196, + 491, + 282 + ], + "lines": [ + { + "bbox": [ + 104, + 196, + 491, + 282 + ], + "spans": [ + { + "bbox": [ + 104, + 196, + 491, + 282 + ], + "type": "table", + "html": "
MethodBackbone#ParamsNYUv2KITTIDIODEScanNetETH3DRank
AbsRel↓δ1↑AbsRel↓δ1↑AbsRel↓δ1↑AbsRel↓δ1↑AbsRel↓δ1↑
DiverseDepth [53]ResNeXt50 [50]25M0.1170.8750.1900.7040.3760.6310.1080.8820.2280.6947.7
MiDaS [32]ResNeXt10188M0.1110.8850.2360.6300.3320.7150.1110.8860.1840.7527.2
Leres [57]ResNeXt1010.0900.9160.1490.7840.2710.7660.0950.9120.1710.7775.4
Omnidata [9]ViT-base0.0740.9450.1490.8350.3390.7420.0770.9350.1660.7784.9
HDN [60]ViT-Large [8]306M0.0690.9480.1150.8670.2460.7800.0800.9390.1210.8333.7
DPT-large [31]ViT-Large0.0980.9030.100.9010.1820.7580.0780.9380.0780.9463.8
Ours LSTM_imageConvNeXt-large [26]198M0.0580.9630.0530.9650.2110.8250.0740.9420.0640.9651.3
Ours LSTM_labelConvNeXt-large0.0500.9660.0580.9700.2240.8050.0740.9410.0660.9641.8
", + "image_path": "c900d073706e61060171b7161f8194b9ca9df57ce89a8c550de5628292da4cc7.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_body" + } + ], + "index": 3 + }, + { + "type": "table", + "bbox": [ + 70, + 314, + 286, + 371 + ], + "blocks": [ + { + "bbox": [ + 72, + 287, + 285, + 313 + ], + "lines": [ + { + "bbox": [ + 72, + 287, + 285, + 313 + ], + "spans": [ + { + "bbox": [ + 72, + 287, + 285, + 313 + ], + "type": "text", + "content": "Table 5 - Comparison with SOTA SLAM methods on KITTI. We input predicted metric depth to the Droid-SLAM [44] ('Droid+Ours'), which outperforms others by a large margin on trajectory accuracy." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 70, + 314, + 286, + 371 + ], + "lines": [ + { + "bbox": [ + 70, + 314, + 286, + 371 + ], + "spans": [ + { + "bbox": [ + 70, + 314, + 286, + 371 + ], + "type": "table", + "html": "
MethodSeq 00Seq 02Seq 05Seq 06Seq 08Seq 09Seq 10
Translational RMS drift (frel, ↓) / Rotational RMS drift (rrel, ↓)
GeoNet [58]27.6/5.7242.24/6.1420.12/7.679.28/4.3418.59/7.8523.94/9.8120.73/9.1
VISO2-M [41]12.66/2.739.47/1.1915.1/3.656.8/1.9314.82/2.523.69/1.2521.01/3.26
ORB-V2 [28]11.43/0.5810.34/0.269.04/0.2614.56/0.2611.46/0.289.3/0.262.57/0.32
Droid [44]33.9/0.2934.88/0.2723.4/0.2717.2/0.2639.6/0.3121.7/0.237/0.25
Droid+Ours1.44/0.372.64/0.291.44/0.250.6/0.22.2/0.31.63/0.222.73/0.23
", + "image_path": "4e6ef86595b29ba66df345043145885f86e3d2c8330ce8a6cbb53fdfaf1e0da1.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "table_body" + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 71, + 418, + 285, + 464 + ], + "blocks": [ + { + "bbox": [ + 72, + 382, + 285, + 417 + ], + "lines": [ + { + "bbox": [ + 72, + 382, + 285, + 417 + ], + "spans": [ + { + "bbox": [ + 72, + 382, + 285, + 417 + ], + "type": "text", + "content": "Table 6 - Effectiveness of our LSTM. CamConvs [11] directly encodes various camera models in the network, while we perform a simple yet effective transformation to solve the metric ambiguity. Without LSTM, the model cannot achieve transferable metric prediction ability." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 71, + 418, + 285, + 464 + ], + "lines": [ + { + "bbox": [ + 71, + 418, + 285, + 464 + ], + "spans": [ + { + "bbox": [ + 71, + 418, + 285, + 464 + ], + "type": "table", + "html": "
MethodDDAD Test set of train.Lyft data (AbsRel↓)DSNS Zero-shot test setKITTI (AbsRel↓)NYU
w/o LSTM0.5300.5820.3941.000.5680.584
CamConvs [11]0.2950.3150.2130.4230.1780.333
Ours CSTM_image0.1900.2350.1820.1970.0970.210
Ours CSTM_label0.1830.2210.2010.2130.0810.212
", + "image_path": "9378d8dbad38191232580891bfbeca6ddebd51a6d2c72d24aecb1eb759789bd6.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_body" + } + ], + "index": 7 + }, + { + "bbox": [ + 69, + 477, + 288, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 477, + 288, + 498 + ], + "spans": [ + { + "bbox": [ + 69, + 477, + 288, + 498 + ], + "type": "text", + "content": "method challenges the data diversity and network capacity, thus our performance is better than theirs." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 69, + 499, + 288, + 597 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 499, + 288, + 597 + ], + "spans": [ + { + "bbox": [ + 69, + 499, + 288, + 597 + ], + "type": "text", + "content": "Ablation on canonical space. We study the effect of the canonical camera here, i.e., the canonical focal length. We train the model on the small sampled dataset and test it on the validation set and testing data. The average AbsRel error is calculated. We experiment on 3 different focal lengths, i.e., 500, 1000, 1500. Experiments show that " + }, + { + "bbox": [ + 69, + 499, + 288, + 597 + ], + "type": "inline_equation", + "content": "\\text{focal} = 1000" + }, + { + "bbox": [ + 69, + 499, + 288, + 597 + ], + "type": "text", + "content": " has slightly better performance than others, see Fig. 8. Thus we set the canonical focal length to 1000 in our experiments." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 69, + 599, + 289, + 686 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 69, + 599, + 289, + 686 + ], + "spans": [ + { + "bbox": [ + 69, + 599, + 289, + 686 + ], + "type": "text", + "content": "Effectiveness of the random proposal normalization loss. To show the effectiveness of our proposed random proposal normalization loss (RPNL), we experiment on the sampled small dataset. Results are shown in Tab. 7. We test on the DDAD, Lyft, DrivingStereo (DS), NuScenes (NS), KITTI, and NYUv2. The 'baseline' employs all losses except our RPNL. We compare it with 'baseline + RPNL' and 'baseline + SSIL [32]'. We can observe that our proposed" + } + ] + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 346, + 285, + 485, + 352 + ], + "blocks": [ + { + "bbox": [ + 346, + 285, + 485, + 352 + ], + "lines": [ + { + "bbox": [ + 346, + 285, + 485, + 352 + ], + "spans": [ + { + "bbox": [ + 346, + 285, + 485, + 352 + ], + "type": "image", + "image_path": "f3b68f34b10e955b406332903e021da7291c37a39932bb3d224f61169b06a1f6.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 309, + 359, + 522, + 386 + ], + "lines": [ + { + "bbox": [ + 309, + 359, + 522, + 386 + ], + "spans": [ + { + "bbox": [ + 309, + 359, + 522, + 386 + ], + "type": "text", + "content": "Figure 8 - Effect of different canonical focal lengths. We experiment on different canonical focal lengths and find that too large or small focal lengths will impact the performance." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "type": "table", + "bbox": [ + 308, + 415, + 524, + 455 + ], + "blocks": [ + { + "bbox": [ + 309, + 388, + 522, + 415 + ], + "lines": [ + { + "bbox": [ + 309, + 388, + 522, + 415 + ], + "spans": [ + { + "bbox": [ + 309, + 388, + 522, + 415 + ], + "type": "text", + "content": "Table 7 - Effectiveness of random proposal normalization loss. Baseline is supervised by " + }, + { + "bbox": [ + 309, + 388, + 522, + 415 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{PWN}} + L_{\\mathrm{VNL}} + L_{\\mathrm{silog}}" + }, + { + "bbox": [ + 309, + 388, + 522, + 415 + ], + "type": "text", + "content": ". SSL is the scale-shift invariant loss proposed in [32]." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 308, + 415, + 524, + 455 + ], + "lines": [ + { + "bbox": [ + 308, + 415, + 524, + 455 + ], + "spans": [ + { + "bbox": [ + 308, + 415, + 524, + 455 + ], + "type": "table", + "html": "
MethodDDAD Test set of train.Lyft data (AbsRel↓)DSNS Zero-shot test setKITTI (AbsRel↓)NYUv2
baseline0.2040.2510.1840.2070.1040.230
baseline + SSL [32]0.1970.2630.2590.2060.1050.216
baseline + RPNL0.1900.2350.1820.1970.0970.210
", + "image_path": "c4a3e8f94ba2d4962a6b9386c4552f5ec2d1917767381b8dfd25af9049caedca.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "table_body" + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 458, + 525, + 502 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 458, + 525, + 502 + ], + "spans": [ + { + "bbox": [ + 306, + 458, + 525, + 502 + ], + "type": "text", + "content": "random proposal normalization loss can further improve the performance. In contrast, the scale-shift invariant loss [32], which does the normalization on the whole image, can only slightly improve the performance." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 514, + 372, + 525 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 514, + 372, + 525 + ], + "spans": [ + { + "bbox": [ + 306, + 514, + 372, + 525 + ], + "type": "text", + "content": "5. Conclusion" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 533, + 526, + 652 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 526, + 652 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 526, + 652 + ], + "type": "text", + "content": "In this paper, we tackle the problem of reconstructing the 3D metric scene from a single monocular image. To solve the depth ambiguity in image appearance caused by various focal lengths, we propose a canonical camera space transformation method. With our method, we can easily merge millions of data captured by 10k cameras to train one metric depth model. To improve the robustness, we collected over 8M data for training. Several zero-shot evaluations show the effectiveness and robustness of our work. We further show the ability to do metrology on randomly collected internet images and dense mapping on large-scale scenes." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 654, + 525, + 686 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 654, + 525, + 686 + ], + "spans": [ + { + "bbox": [ + 306, + 654, + 525, + 686 + ], + "type": "text", + "content": "Acknowledgements This work was in part supported by National Key R&D Program of China (No. 2022ZD0118700)." + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "spans": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "text", + "content": "9050" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 70, + 99, + 123, + 110 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 99, + 123, + 110 + ], + "spans": [ + { + "bbox": [ + 70, + 99, + 123, + 110 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 70, + 117, + 289, + 687 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 74, + 117, + 289, + 147 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 117, + 289, + 147 + ], + "spans": [ + { + "bbox": [ + 74, + 117, + 289, + 147 + ], + "type": "text", + "content": "[1] Jonathan T Barron and Jitendra Malik. Shape, illumination, and reflectance from shading. IEEE Trans. Pattern Anal. Mach. Intell., 37(8):1670-1687, 2014. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 74, + 148, + 288, + 187 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 148, + 288, + 187 + ], + "spans": [ + { + "bbox": [ + 74, + 148, + 288, + 187 + ], + "type": "text", + "content": "[2] Shariq Farooq Bhat, Ibrahim Alhashim, and Peter Wonka. Adabins: Depth estimation using adaptive bins. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 4009-4018, 2021. 2, 3, 6, 8" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 74, + 189, + 289, + 228 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 189, + 289, + 228 + ], + "spans": [ + { + "bbox": [ + 74, + 189, + 289, + 228 + ], + "type": "text", + "content": "[3] Jia-Wang Bian, Huangying Zhan, Naiyan Wang, Tat-Jin Chin, Chunhua Shen, and Ian Reid. Auto-rectify network for unsupervised indoor depth estimation. IEEE Trans. Pattern Anal. Mach. Intell., 2021. 6, 7" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 74, + 229, + 288, + 280 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 229, + 288, + 280 + ], + "spans": [ + { + "bbox": [ + 74, + 229, + 288, + 280 + ], + "type": "text", + "content": "[4] Holger Caesar, Varun Bankiti, Alex H Lang, Sourabh Vora, Venice Erin Liong, Qiang Xu, Anush Krishnan, Yu Pan, Giancarlo Baldan, and Oscar Beijbom. nuscenes: A multimodal dataset for autonomous driving. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 11621-11631, 2020. 5" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 74, + 281, + 288, + 310 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 281, + 288, + 310 + ], + "spans": [ + { + "bbox": [ + 74, + 281, + 288, + 310 + ], + "type": "text", + "content": "[5] Weifeng Chen, Zhao Fu, Dawei Yang, and Jia Deng. Single-image depth perception in the wild. In Proc. Advances in Neural Inf. Process. Syst., pages 730-738, 2016. 2, 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 74, + 311, + 288, + 350 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 311, + 288, + 350 + ], + "spans": [ + { + "bbox": [ + 74, + 311, + 288, + 350 + ], + "type": "text", + "content": "[6] Weifeng Chen, Shengyi Qian, David Fan, Noriyuki Kojima, Max Hamilton, and Jia Deng. Oasis: A large-scale dataset for single image 3d in the wild. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 679-688, 2020. 2, 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 74, + 352, + 289, + 401 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 352, + 289, + 401 + ], + "spans": [ + { + "bbox": [ + 74, + 352, + 289, + 401 + ], + "type": "text", + "content": "[7] Angela Dai, Angel X Chang, Manolis Savva, Maciej Halber, Thomas Funkhouser, and Matthias Nießner. Scannet: Richly-annotated 3d reconstructions of indoor scenes. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 5828-5839, 2017. 5" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 74, + 402, + 288, + 462 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 402, + 288, + 462 + ], + "spans": [ + { + "bbox": [ + 74, + 402, + 288, + 462 + ], + "type": "text", + "content": "[8] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, Jakob Uszkoreit, and Neil Houlsby. An image is worth 16x16 words: Transformers for image recognition at scale. Proc. Int. Conf. Learn. Representations, 2021. 8" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 74, + 463, + 288, + 502 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 74, + 463, + 288, + 502 + ], + "spans": [ + { + "bbox": [ + 74, + 463, + 288, + 502 + ], + "type": "text", + "content": "[9] Ainaz Eftekhar, Alexander Sax, Jitendra Malik, and Amir Zamir. Omnidata: A scalable pipeline for making multi-task mid-level vision datasets from 3d scans. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 10786-10796, 2021. 3, 8" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 70, + 503, + 288, + 543 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 503, + 288, + 543 + ], + "spans": [ + { + "bbox": [ + 70, + 503, + 288, + 543 + ], + "type": "text", + "content": "[10] David Eigen, Christian Puhrsch, and Rob Fergus. Depth map prediction from a single image using a multi-scale deep network. In Proc. Advances in Neural Inf. Process. Syst., pages 2366-2374, 2014. 3, 5" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 70, + 544, + 288, + 594 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 544, + 288, + 594 + ], + "spans": [ + { + "bbox": [ + 70, + 544, + 288, + 594 + ], + "type": "text", + "content": "[11] Jose Facil, Benjamin Ummenhofer, Huizhong Zhou, Luis Montesano, Thomas Brox, and Javier Civera. CAM-Convs: camera-aware multi-scale convolutions for single-view depth. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 11826-11835, 2019. 2, 7, 8" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 70, + 595, + 288, + 624 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 595, + 288, + 624 + ], + "spans": [ + { + "bbox": [ + 70, + 595, + 288, + 624 + ], + "type": "text", + "content": "[12] Andreas Geiger, Philip Lenz, Christoph Stiller, and Raquel Urtasun. Vision meets robotics: The kitti dataset. Int. J. Robot. Res., 2013. 3, 5, 6" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 70, + 625, + 288, + 665 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 625, + 288, + 665 + ], + "spans": [ + { + "bbox": [ + 70, + 625, + 288, + 665 + ], + "type": "text", + "content": "[13] Andreas Geiger, Philip Lenz, and Raquel Urtasun. Are we ready for autonomous driving? the kitti vision benchmark suite. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 3354-3361. IEEE, 2012. 6" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 70, + 666, + 288, + 687 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 70, + 666, + 288, + 687 + ], + "spans": [ + { + "bbox": [ + 70, + 666, + 288, + 687 + ], + "type": "text", + "content": "[14] Xiaoyang Guo, Hongsheng Li, Shuai Yi, Jimmy Ren, and Xiaogang Wang. Learning monocular depth by distilling" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 101, + 524, + 686 + ], + "type": "list", + "angle": 0, + "index": 32, + "blocks": [ + { + "bbox": [ + 326, + 101, + 524, + 121 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 326, + 101, + 524, + 121 + ], + "spans": [ + { + "bbox": [ + 326, + 101, + 524, + 121 + ], + "type": "text", + "content": "cross-domain stereo networks. In Proc. Eur. Conf. Comp. Vis., pages 484-500, 2018. 6" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 122, + 524, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 122, + 524, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 122, + 524, + 150 + ], + "type": "text", + "content": "[15] Richard Hartley and Andrew Zisserman. Multiple view geometry in computer vision. Cambridge university press, 2003. 2" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 152, + 524, + 203 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 524, + 203 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 524, + 203 + ], + "type": "text", + "content": "[16] Yannick Hold-Geoffroy, Kalyan Sunkavalli, Jonathan Eisenmann, Matthew Fisher, Emiliano Gambaretto, Sunil Hadap, and Jean-François Lalonde. A perceptual measure for deep single image camera calibration. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2354-2363, 2018. 4" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 204, + 524, + 234 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 204, + 524, + 234 + ], + "spans": [ + { + "bbox": [ + 307, + 204, + 524, + 234 + ], + "type": "text", + "content": "[17] Sunghoon Im, Hae-Gon Jeon, Stephen Lin, and In-So Kweon. Dpsnet: End-to-end deep plane sweep stereo. In Proc. Int. Conf. Learn. Representations, 2019. 3, 6, 7" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 235, + 524, + 265 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 235, + 524, + 265 + ], + "spans": [ + { + "bbox": [ + 307, + 235, + 524, + 265 + ], + "type": "text", + "content": "[18] Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. Tanks and temples: Benchmarking large-scale scene reconstruction. ACM Trans. Graph., 36(4):1-13, 2017. 5" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 266, + 524, + 305 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 266, + 524, + 305 + ], + "spans": [ + { + "bbox": [ + 307, + 266, + 524, + 305 + ], + "type": "text", + "content": "[19] Tobias Koch, Lukas Liebel, Friedrich Fraundorfer, and Marco Korner. Evaluation of cnn-based single-image depth estimation methods. In *Eur. Conf. Comput. Vis. Worksh.*, pages 0–0, 2018. 5" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 307, + 524, + 337 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 307, + 524, + 337 + ], + "spans": [ + { + "bbox": [ + 307, + 307, + 524, + 337 + ], + "type": "text", + "content": "[20] Johannes Kopf, Xuejian Rong, and Jia-Bin Huang. Robust consistent video depth estimation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2021. 6, 7" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 338, + 524, + 388 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 338, + 524, + 388 + ], + "spans": [ + { + "bbox": [ + 307, + 338, + 524, + 388 + ], + "type": "text", + "content": "[21] Iro Laina, Christian Rupprecht, Vasileios Belagiannis, Federico Tombari, and Nassir Navab. Deeper depth prediction with fully convolutional residual networks. In 2016 Fourth international conference on 3D vision (3DV), pages 239-248. IEEE, 2016. 6" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 388, + 524, + 429 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 388, + 524, + 429 + ], + "spans": [ + { + "bbox": [ + 307, + 388, + 524, + 429 + ], + "type": "text", + "content": "[22] John Lambert, Zhuang Liu, Ozan Sener, James Hays, and Vladlen Koltun. Mseg: A composite dataset for multi-domain semantic segmentation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2879-2888, 2020. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 430, + 524, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 430, + 524, + 470 + ], + "spans": [ + { + "bbox": [ + 307, + 430, + 524, + 470 + ], + "type": "text", + "content": "[23] Jun Li, Reinhard Klein, and Angela Yao. A two-streamed network for estimating fine-scaled depth maps from singlergb images. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 3372-3380, 2017. 6" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 471, + 524, + 511 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 471, + 524, + 511 + ], + "spans": [ + { + "bbox": [ + 307, + 471, + 524, + 511 + ], + "type": "text", + "content": "[24] Shunkai Li, Xin Wu, Yingdian Cao, and Hongbin Zha. Generalizing to the open world: Deep visual odometry with online adaptation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 13184-13193, 2021. 5" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 512, + 524, + 551 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 512, + 524, + 551 + ], + "spans": [ + { + "bbox": [ + 307, + 512, + 524, + 551 + ], + "type": "text", + "content": "[25] Yifan Liu, Hao Chen, Yu Chen, Wei Yin, and Chunhua Shen. Generic perceptual loss for modeling structured output dependencies. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2021. 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 552, + 524, + 593 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 552, + 524, + 593 + ], + "spans": [ + { + "bbox": [ + 307, + 552, + 524, + 593 + ], + "type": "text", + "content": "[26] Zhuang Liu, Hanzi Mao, Chao-Yuan Wu, Christoph Feichtenhofer, Trevor Darrell, and Saining Xie. A convnet for the 2020s. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 11976-11986, 2022. 5, 8" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 594, + 524, + 633 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 594, + 524, + 633 + ], + "spans": [ + { + "bbox": [ + 307, + 594, + 524, + 633 + ], + "type": "text", + "content": "[27] Raul Mur-Artal and Juan D Tardós. Orb-slam2: An open-source slam system for monocular, stereo, and rgb-d cameras. IEEE transactions on robotics, 33(5):1255-1262, 2017. 3" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 635, + 524, + 665 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 635, + 524, + 665 + ], + "spans": [ + { + "bbox": [ + 307, + 635, + 524, + 665 + ], + "type": "text", + "content": "[28] Raul Mur-Artal and Juan D. Tardós. ORB-SLAM2: an open-source SLAM system for monocular, stereo and RGB-D cameras. IEEE Trans. Robot., 33(5):1255-1262, 2017. 8" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 307, + 666, + 524, + 686 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 666, + 524, + 686 + ], + "spans": [ + { + "bbox": [ + 307, + 666, + 524, + 686 + ], + "type": "text", + "content": "[29] Sida Peng, Shangzhan Zhang, Zhen Xu, Chen Geng, Boyi Jiang, Hujun Bao, and Xiaowei Zhou. Animatable neural" + } + ] + } + ], + "index": 31 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 704, + 313, + 712 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 704, + 313, + 712 + ], + "spans": [ + { + "bbox": [ + 296, + 704, + 313, + 712 + ], + "type": "text", + "content": "9051" + } + ] + } + ], + "index": 33 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 71, + 101, + 288, + 686 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 88, + 101, + 288, + 121 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 88, + 101, + 288, + 121 + ], + "spans": [ + { + "bbox": [ + 88, + 101, + 288, + 121 + ], + "type": "text", + "content": "implicit surfaces for creating avatars from videos. arXiv: Comp. Res. Repository, page 2203.08133, 2022. 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 71, + 122, + 288, + 181 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 122, + 288, + 181 + ], + "spans": [ + { + "bbox": [ + 71, + 122, + 288, + 181 + ], + "type": "text", + "content": "[30] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In Proc. Int. Conf. Mach. Learn., pages 8748-8763. PMLR, 2021. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 71, + 183, + 288, + 213 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 183, + 288, + 213 + ], + "spans": [ + { + "bbox": [ + 71, + 183, + 288, + 213 + ], + "type": "text", + "content": "[31] René Ranftl, Alexey Bochkovskiy, and Vladlen Koltun. Vision transformers for dense prediction. In Proc. IEEE Int. Conf. Comp. Vis., pages 12179-12188, 2021. 2, 6, 7, 8" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 71, + 214, + 288, + 263 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 214, + 288, + 263 + ], + "spans": [ + { + "bbox": [ + 71, + 214, + 288, + 263 + ], + "type": "text", + "content": "[32] René Ranftl, Katrin Lasinger, David Hafner, Konrad Schindler, and Vladlen Koltun. Towards robust monocular depth estimation: Mixing datasets for zero-shot cross-dataset transfer. IEEE Trans. Pattern Anal. Mach. Intell., 2020. 2, 3, 5, 8" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 71, + 265, + 288, + 315 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 265, + 288, + 315 + ], + "spans": [ + { + "bbox": [ + 71, + 265, + 288, + 315 + ], + "type": "text", + "content": "[33] Shunsuke Saito, Zeng Huang, Ryota Natsume, Shigeo Morishima, Angjoo Kanazawa, and Hao Li. Pifu: Pixel-aligned implicit function for high-resolution clothed human digitization. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2304-2314, 2019. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 71, + 317, + 288, + 357 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 317, + 288, + 357 + ], + "spans": [ + { + "bbox": [ + 71, + 317, + 288, + 357 + ], + "type": "text", + "content": "[34] Shunsuke Saito, Tomas Simon, Jason Saragih, and Hanbyul Joo. Pifuhd: Multi-level pixel-aligned implicit function for high-resolution 3d human digitization. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 84-93, 2020. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 71, + 358, + 288, + 388 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 358, + 288, + 388 + ], + "spans": [ + { + "bbox": [ + 71, + 358, + 288, + 388 + ], + "type": "text", + "content": "[35] Ashutosh Saxena, Min Sun, and Andrew Y Ng. Make3d: Learning 3d scene structure from a single still image. IEEE Trans. Pattern Anal. Mach. Intell., 31(5):824-840, 2008. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 71, + 389, + 288, + 428 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 389, + 288, + 428 + ], + "spans": [ + { + "bbox": [ + 71, + 389, + 288, + 428 + ], + "type": "text", + "content": "[36] Johannes Lutz Schonberger, Enliang Zheng, Marc Pollefeys, and Jan-Michael Frahm. Pixelwise view selection for unstructured multi-view stereo. In Proc. Eur. Conf. Comp. Vis., 2016. 5" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 71, + 430, + 288, + 480 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 430, + 288, + 480 + ], + "spans": [ + { + "bbox": [ + 71, + 430, + 288, + 480 + ], + "type": "text", + "content": "[37] Thomas Schops, Johannes L Schonberger, Silvano Galliani, Torsten Sattler, Konrad Schindler, Marc Pollefeys, and Andreas Geiger. A multi-view stereo benchmark with high-resolution images and multi-camera videos. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 3260-3269, 2017. 5" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 71, + 482, + 288, + 531 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 482, + 288, + 531 + ], + "spans": [ + { + "bbox": [ + 71, + 482, + 288, + 531 + ], + "type": "text", + "content": "[38] Jamie Shotton, Ben Glocker, Christopher Zach, Shahram Izadi, Antonio Criminisi, and Andrew Fitzgibbon. Scene coordinate regression forests for camera relocalization in rgb-d images. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 2930-2937, 2013. 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 71, + 533, + 288, + 572 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 533, + 288, + 572 + ], + "spans": [ + { + "bbox": [ + 71, + 533, + 288, + 572 + ], + "type": "text", + "content": "[39] Nathan Silberman, Derek Hoiem, Pushmeet Kohli, and Rob Fergus. Indoor segmentation and support inference from rgbd images. In Proc. Eur. Conf. Comp. Vis., pages 746-760. Springer, 2012. 3, 5, 6" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 71, + 574, + 288, + 604 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 574, + 288, + 604 + ], + "spans": [ + { + "bbox": [ + 71, + 574, + 288, + 604 + ], + "type": "text", + "content": "[40] Dalwinder Singh and Birmohan Singh. Investigating the impact of data normalization on classification performance. Applied Soft Computing, 2019. 5" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 71, + 605, + 288, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 605, + 288, + 644 + ], + "spans": [ + { + "bbox": [ + 71, + 605, + 288, + 644 + ], + "type": "text", + "content": "[41] Shiyu Song, Manmohan Chandraker, and Clark C Guest. High accuracy monocular sfm and scale correction for autonomous driving. IEEE Trans. Pattern Anal. Mach. Intell., 38(4):730-743, 2015. 8" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 71, + 647, + 288, + 686 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 647, + 288, + 686 + ], + "spans": [ + { + "bbox": [ + 71, + 647, + 288, + 686 + ], + "type": "text", + "content": "[42] Jaime Spencer, C. Stella Qian, Michaela Trescakova, Chris Russell, Simon Hadfield, Erich W. Graf, Wendy J. Adams, Andrew J. Schofield, James Elder, Richard Bowden, Ali Anwar, Hao Chen, Xiaozhi Chen, Kai Cheng, Yuchao Dai," + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 101, + 525, + 686 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 325, + 101, + 525, + 200 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 325, + 101, + 525, + 200 + ], + "spans": [ + { + "bbox": [ + 325, + 101, + 525, + 200 + ], + "type": "text", + "content": "Huynh Thai Hoa, Sadat Hossain, Jianmian Huang, Mohan Jing, Bo Li, Chao Li, Baojun Li, Zhiwen Liu, Stefano Mattoccia, Siegfried Mercelis, Myungwoo Nam, Matteo Poggi, Xiaohua Qi, Jiahui Ren, Yang Tang, Fabio Tosi, Linh Trinh, S. M. Nadim Uddin, Khan Muhammad Umair, Kaixuan Wang, Yufei Wang, Yixing Wang, Mochu Xiang, Guangkai Xu, Wei Yin, Jun Yu, Qi Zhang, and Chaoqiang Zhao. The second monocular depth estimation challenge. In IEEE Conf. Comput. Vis. Pattern Recog. Worksh., pages 3063-3075, June 2023. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 202, + 525, + 241 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 202, + 525, + 241 + ], + "spans": [ + { + "bbox": [ + 308, + 202, + 525, + 241 + ], + "type": "text", + "content": "[43] Libo Sun, Wei Yin, Enze Xie, Zhengrong Li, Changming Sun, and Chunhua Shen. Improving monocular visual odometry using learned depth. IEEE Transactions on Robotics, 38(5):3173-3186, 2022. 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 243, + 525, + 273 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 243, + 525, + 273 + ], + "spans": [ + { + "bbox": [ + 308, + 243, + 525, + 273 + ], + "type": "text", + "content": "[44] Zachary Teed and Jia Deng. Droid-slam: Deep visual slam for monocular, stereo, and rgb-d cameras. volume 34, pages 16558-16569, 2021. 1, 3, 6, 8" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 275, + 525, + 325 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 275, + 525, + 325 + ], + "spans": [ + { + "bbox": [ + 308, + 275, + 525, + 325 + ], + "type": "text", + "content": "[45] Igor Vasiljevic, Nick Kolkin, Shanyi Zhang, Ruotian Luo, Haochen Wang, Falcon Z Dai, Andrea F Daniele, Mohammadreza Mostajabi, Steven Basart, Matthew R Walter, et al. Diode: A dense indoor and outdoor depth dataset. arXiv: Comp. Res. Repository, page 1908.00463, 2019. 5" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 327, + 525, + 365 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 327, + 525, + 365 + ], + "spans": [ + { + "bbox": [ + 308, + 327, + 525, + 365 + ], + "type": "text", + "content": "[46] Nanyang Wang, Yinda Zhang, Zhuwen Li, Yanwei Fu, Wei Liu, and Yu-Gang Jiang. Pixel2mesh: Generating 3d mesh models from single RGB images. In Proc. Eur. Conf. Comp. Vis., pages 52-67, 2018. 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 367, + 525, + 416 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 367, + 525, + 416 + ], + "spans": [ + { + "bbox": [ + 308, + 367, + 525, + 416 + ], + "type": "text", + "content": "[47] Jiajun Wu, Chengkai Zhang, Xiuming Zhang, Zhoutong Zhang, William Freeman, and Joshua Tenenbaum. Learning shape priors for single-view 3d completion and reconstruction. In Proc. Eur. Conf. Comp. Vis., pages 646-662, 2018. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 418, + 525, + 458 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 418, + 525, + 458 + ], + "spans": [ + { + "bbox": [ + 308, + 418, + 525, + 458 + ], + "type": "text", + "content": "[48] Ke Xian, Chunhua Shen, Zhiguo Cao, Hao Lu, Yang Xiao, Ruibo Li, and Zhenbo Luo. Monocular relative depth perception with web stereo data supervision. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 311-320, 2018. 2, 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 460, + 525, + 499 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 460, + 525, + 499 + ], + "spans": [ + { + "bbox": [ + 308, + 460, + 525, + 499 + ], + "type": "text", + "content": "[49] Ke Xian, Jianming Zhang, Oliver Wang, Long Mai, Zhe Lin, and Zhiguo Cao. Structure-guided ranking loss for single image depth prediction. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 611-620, 2020. 2, 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 501, + 525, + 540 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 501, + 525, + 540 + ], + "spans": [ + { + "bbox": [ + 308, + 501, + 525, + 540 + ], + "type": "text", + "content": "[50] Saining Xie, Ross Girshick, Piotr Dólar, Zhuowen Tu, and Kaiming He. Aggregated residual transformations for deep neural networks. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., pages 1492-1500, 2017. 8" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 543, + 525, + 582 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 543, + 525, + 582 + ], + "spans": [ + { + "bbox": [ + 308, + 543, + 525, + 582 + ], + "type": "text", + "content": "[51] Guangkai Xu, Wei Yin, Hao Chen, Chunhua Shen, Kai Cheng, and Feng Zhao. Pose-free 3d scene reconstruction with frozen depth models. In Proc. IEEE Int. Conf. Comp. Vis., 2023. 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 584, + 525, + 623 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 584, + 525, + 623 + ], + "spans": [ + { + "bbox": [ + 308, + 584, + 525, + 623 + ], + "type": "text", + "content": "[52] Guanglei Yang, Hao Tang, Mingli Ding, Nicu Sebe, and Elisa Ricci. Transformer-based attention networks for continuous pixel-wise prediction. In Proc. IEEE Int. Conf. Comp. Vis., 2021. 2, 6" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 625, + 525, + 663 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 625, + 525, + 663 + ], + "spans": [ + { + "bbox": [ + 308, + 625, + 525, + 663 + ], + "type": "text", + "content": "[53] Wei Yin, Yifan Liu, and Chunhua Shen. Virtual normal: Enforcing geometric constraints for accurate and robust depth prediction. IEEE Trans. Pattern Anal. Mach. Intell., 2021. 2, 3, 5, 8" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 666, + 525, + 686 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 666, + 525, + 686 + ], + "spans": [ + { + "bbox": [ + 308, + 666, + 525, + 686 + ], + "type": "text", + "content": "[54] Wei Yin, Yifan Liu, Chunhua Shen, Anton van den Hengel, and Baichuan Sun. The devil is in the labels: Semantic seg" + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "spans": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "text", + "content": "9052" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 71, + 101, + 289, + 439 + ], + "type": "list", + "angle": 0, + "index": 9, + "blocks": [ + { + "bbox": [ + 88, + 101, + 288, + 121 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 88, + 101, + 288, + 121 + ], + "spans": [ + { + "bbox": [ + 88, + 101, + 288, + 121 + ], + "type": "text", + "content": "mentation from sentences. arXiv: Comp. Res. Repository, page 2202.02002, 2022.3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 71, + 122, + 289, + 152 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 122, + 289, + 152 + ], + "spans": [ + { + "bbox": [ + 71, + 122, + 289, + 152 + ], + "type": "text", + "content": "[55] Wei Yin, Yifan Liu, Chunhua Shen, and Youliang Yan. Enforcing geometric constraints of virtual normal for depth prediction. In Proc. IEEE Int. Conf. Comp. Vis., 2019. 2, 3, 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 71, + 153, + 288, + 192 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 153, + 288, + 192 + ], + "spans": [ + { + "bbox": [ + 71, + 153, + 288, + 192 + ], + "type": "text", + "content": "[56] Wei Yin, Jianming Zhang, Oliver Wang, Simon Niklaus, Simon Chen, Yifan Liu, and Chunhua Shen. Towards accurate reconstruction of 3d scene shape from a single monocular image. IEEE Trans. Pattern Anal. Mach. Intell., 2022. 2, 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 71, + 194, + 288, + 233 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 194, + 288, + 233 + ], + "spans": [ + { + "bbox": [ + 71, + 194, + 288, + 233 + ], + "type": "text", + "content": "[57] Wei Yin, Jianming Zhang, Oliver Wang, Simon Niklaus, Long Mai, Simon Chen, and Chunhua Shen. Learning to recover 3d scene shape from a single image. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2021. 1, 2, 3, 4, 5, 6, 7, 8" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 71, + 235, + 288, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 235, + 288, + 274 + ], + "spans": [ + { + "bbox": [ + 71, + 235, + 288, + 274 + ], + "type": "text", + "content": "[58] Zhichao Yin and Jianping Shi. Geonet: Unsupervised learning of dense depth, optical flow and camera pose. In Proceedings of the IEEE conference on computer vision and pattern recognition, pages 1983-1992, 2018. 8" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 71, + 276, + 288, + 315 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 276, + 288, + 315 + ], + "spans": [ + { + "bbox": [ + 71, + 276, + 288, + 315 + ], + "type": "text", + "content": "[59] Weihao Yuan, Xiaodong Gu, Zuozhuo Dai, Siyu Zhu, and Ping Tan. New CRFs: Neural window fully-connected CRFs for monocular depth estimation. In Proc. IEEE Conf. Comp. Vis. Patt. Recogn., 2022. 2, 3, 6, 8" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 71, + 317, + 288, + 356 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 317, + 288, + 356 + ], + "spans": [ + { + "bbox": [ + 71, + 317, + 288, + 356 + ], + "type": "text", + "content": "[60] Chi Zhang, Wei Yin, Zhibin Wang, Gang Yu, Bin Fu, and Chunhua Shen. Hierarchical normalization for robust monocular depth estimation. Proc. Advances in Neural Inf. Process. Syst., 2022. 2, 3, 5, 8" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 71, + 357, + 288, + 397 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 357, + 288, + 397 + ], + "spans": [ + { + "bbox": [ + 71, + 357, + 288, + 397 + ], + "type": "text", + "content": "[61] Chi Zhang, Wei Yin, Gang Yu, Zhibin Wang, Tao Chen, Bin Fu, Joey Tianyi Zhou, and Chunhua Shen. Robust geometry-preserving depth estimation using differentiable rendering. In Proc. IEEE Int. Conf. Comp. Vis., 2023. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 71, + 399, + 288, + 439 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 71, + 399, + 288, + 439 + ], + "spans": [ + { + "bbox": [ + 71, + 399, + 288, + 439 + ], + "type": "text", + "content": "[62] Rui Zhu, Xingyi Yang, Yannick Hold-Geoffroy, Federico Perazzi, Jonathan Eisenmann, Kalyan Sunkavalli, and Manmohan Chandraker. Single view metrology in the wild. In Proc. Eur. Conf. Comp. Vis., pages 316-333. Springer, 2020." + } + ] + } + ], + "index": 8 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "spans": [ + { + "bbox": [ + 296, + 704, + 314, + 712 + ], + "type": "text", + "content": "9053" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/d009dfab-0a08-423e-b77c-b88a4b5cf703_content_list.json b/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/d009dfab-0a08-423e-b77c-b88a4b5cf703_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..830ffdc991d5f5728e5e57b489bb652d4cf366d9 --- /dev/null +++ b/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/d009dfab-0a08-423e-b77c-b88a4b5cf703_content_list.json @@ -0,0 +1,1464 @@ +[ + { + "type": "text", + "text": "Mimic3D: Thriving 3D-Aware GANs via 3D-to-2D Imitation", + "text_level": 1, + "bbox": [ + 181, + 130, + 789, + 151 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Xingyu Chen* Yu Deng* Baoyuan Wang Xiaobing.AI", + "bbox": [ + 303, + 180, + 665, + 217 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 251, + 313, + 266 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Generating images with both photorealism and multiview 3D consistency is crucial for 3D-aware GANs, yet existing methods struggle to achieve them simultaneously. Improving the photorealism via CNN-based 2D super-resolution can break the strict 3D consistency, while keeping the 3D consistency by learning high-resolution 3D representations for direct rendering often compromises image quality. In this paper, we propose a novel learning strategy, namely 3D-to-2D imitation, which enables a 3D-aware GAN to generate high-quality images while maintaining their strict 3D consistency, by letting the images synthesized by the generator's 3D rendering branch mimic those generated by its 2D super-resolution branch. We also introduce 3D-aware convolutions into the generator for better 3D representation learning, which further improves the image generation quality. With the above strategies, our method reaches FID scores of 5.4 and 4.3 on FFHQ and AFHQ-v2 Cats, respectively, at $512 \\times 512$ resolution, largely outperforming existing 3D-aware GANs using direct 3D rendering and coming very close to the previous state-of-the-art method that leverages 2D super-resolution. Project website: https://seancheny.github.io/Mimic3DWeb.", + "bbox": [ + 75, + 282, + 472, + 630 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 657, + 207, + 672 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "3D-aware GANs [35, 9, 6, 3] have experienced rapid development in recent years and shown great potential for large-scale realistic 3D content creation. The core of 3D-aware GANs is to incorporate 3D representation learning and differentiable rendering into image-level adversarial learning [8]. In this way, the generated 3D representations are forced to mimic real image distribution from arbitrary viewing angles, resulting in their faithful reconstruction of the underlying 3D structures of the subjects for free-view image synthesis. Among different 3D representations, neural radiance field (NeRF) [23] has been proven to be effective in the 3D-aware GAN scenario [35, 4], which guarantees strong 3D consistency when synthesizing multiview", + "bbox": [ + 75, + 681, + 468, + 878 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/5d543cc189a12fdc2d92e21927db9373e1468b78ca41ba399cbc799c49479c03.jpg", + "image_caption": [ + "Figure 1. Comparison between different 3D-aware GANs on image generation quality and multiview 3D consistency. The image generation quality is evaluated via FID between generated and real images. The 3D consistency is measured by conducting 3D reconstruction [43] on generated multiview images and calculating PSNR between them and the re-rendered reconstruction results. Our method inherits the high image quality of approaches leveraging 2D super-resolution meanwhile maintains strict 3D consistency by taking the advantage of direct 3D rendering." + ], + "image_footnote": [], + "bbox": [ + 504, + 250, + 890, + 431 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "images via volume rendering [14].", + "bbox": [ + 500, + 592, + 730, + 607 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "However, NeRF's volumetric representation also brings high computation costs to GAN training. This hinders the generative models from synthesizing high-resolution images with fine details. Several attempts have been made to facilitate NeRF-based GAN training at high resolution, via sparse representations [36, 6, 45, 52] or patch-wise adversarial learning [41], yet the performance is still unsatisfactory and lags far behind state-of-the-art 2D GANs [18, 16].", + "bbox": [ + 496, + 609, + 892, + 731 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Along another line, instead of using direct NeRF rendering, plenty of works [25, 9, 27, 3, 48] introduce 2D super-resolution module to deal with 3D-aware GAN training at high resolution. A typical procedure is to first render a NeRF-like feature field into low-resolution feature maps, then apply a 2D CNN to generate high-resolution images from them. The representative work among this line, namely EG3D [3], utilizes tri-plane representation to effectively model the low-resolution feature field and leverages StyleGAN2-like [18] super-resolution block to achieve image synthesis at high-quality. It sets a record for image", + "bbox": [ + 496, + 734, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*These authors have contributed equally to this work.", + "bbox": [ + 94, + 886, + 377, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "2338", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/37405ceb46c1fb694d9a2fee9073fbba0c0f776941bdb01c291334cbc2b6acc9.jpg", + "image_caption": [ + "Figure 2. Our method enables high-quality image generation at $512 \\times 512$ resolution without using a 2D super-resolution module." + ], + "image_footnote": [], + "bbox": [ + 81, + 89, + 890, + 231 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "quality among 3D-aware GANs and gets very close to that of state-of-the-art 2D GANs. However, a fatal drawback of this line of works is a sacrifice of strict 3D consistency, due to leveraging a black-box 2D CNN for image synthesis.", + "bbox": [ + 75, + 277, + 468, + 338 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "A question naturally arises — Is there any way to combine the above two lines to achieve strict 3D consistency and high-quality image generation simultaneously? The answer, as we will show in this paper, is arguably yes. The key intuition is to let the images synthesized by direct NeRF rendering to mimic those generated by a 2D superresolution module, which we name 3D-to-2D imitation.", + "bbox": [ + 75, + 340, + 468, + 445 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Specifically, we start from an EG3D backbone that adopts 2D super-resolution to generate high-resolution images from a low-resolution feature field. Based on this architecture, we add another 3D super-resolution module to generate high-resolution NeRF from the low-resolution feature field and force the images rendered by the former to imitate those generated by the 2D super-resolution branch. This process can be seen as a multiview reconstruction process — images sharing the same latent code from different views produced by the 2D branch are pseudo multiview data, and the high-resolution NeRF branch represents the 3D scene to be reconstructed. Previous methods [28, 51, 32] have shown that this procedure can obtain reasonable 3D reconstruction, even if the multiview data are not strictly 3D consistent. We believe this is partially due to the inductive bias (e.g., continuity and sparsity) of the underlying 3D representation. With the above process, the high-resolution NeRF learns to depict fine details of the 2D-branch images, thus enabling high-quality image rendering. The 3D consistency across different views can also be preserved thanks to the intrinsic property of NeRF. Note that if the rendered images try to faithfully reconstruct every detail of the 2D-branch images across different views, it is likely to obtain blurry results due to detail-level 3D inconsistency of the latter. To avoid this problem, we only let the images produced by the two branches be perceptually similar (i.e. by LPIPS loss [49]), and further enforce adversarial loss between the rendered images from the high-resolution NeRF and real images to maintain high-frequency details. In addition, we only render small image patches to conduct the imitative", + "bbox": [ + 75, + 446, + 470, + 900 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "learning to reduce memory costs.", + "bbox": [ + 500, + 277, + 720, + 292 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Apart from the above learning strategy, we introduce 3D-aware convolutions to the EG3D backbone to improve tri-plane learning, motivated by a recent 3D diffusion model [44]. The original EG3D generates tri-plane features to model the low-resolution feature field via a StyleGAN2-like generator. The generator is forced to learn 2D-unaligned features on the three orthogonal planes via 2D convolutions, which is inefficient. The 3D-aware convolution considers associated features in 3D space when performing 2D convolution, which improves feature communications and helps to produce more reasonable tri-planes. Nevertheless, directly applying 3D-aware convolution in all layers in the generator is unaffordable. As a result, we only apply them after the output layers at each resolution in the tri-plane generator. This helps us to further improve the image generation quality with only a minor increase in the total memory consumption.", + "bbox": [ + 496, + 294, + 890, + 551 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "With the above strategies, our generator is able to synthesize 3D-consistent images of virtual subjects with high image quality (Fig. 2). It reaches FID scores [12] of 5.4 and 4.3 on FFHQ [17] and AFHQ-v2 Cats [5], respectively, at $512 \\times 512$ resolution, largely outperforming previous 3D-aware GANs with direct 3D rendering and even surpassing many leveraging 2D super-resolution (Fig. 1). A by-product of our method is a more powerful 2D-branch generator, which reaches an FID of 4.1 on FFHQ, exceeding previous state-of-the-art EG3D. Though our method presented in this paper is mostly based on EG3D backbone, its 3D-to-2D imitation strategy can be extended to learning other 3D-aware GANs as well. We believe this would largely close the quality gap between 3D-aware GANs and traditional 2D GANs, and pave a new way for realistic 3D generation.", + "bbox": [ + 496, + 553, + 892, + 780 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Works", + "text_level": 1, + "bbox": [ + 500, + 797, + 650, + 813 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "3D-aware GAN. 3D-aware GANs [11, 24, 35, 4, 25, 9, 50, 6, 3, 41, 52] aim to generate multiview images of an object category, given only in-the-wild 2D images as training data. The key is to represent the generated scenes via a 3D representation and leverage corresponding rendering", + "bbox": [ + 496, + 824, + 890, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "2339", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "techniques to synthesize images at different viewpoints for image-level adversarial learning [8]. Initially, explicit representations such as voxels [24, 11] and meshes [42] are used to describe scenes. With the development of neural implicit fields [31, 22, 40, 39, 23, 43, 26], implicit scene representations, especially NeRF [23], gradually overtake explicit ones in 3D-aware GANs [4, 27, 3]. Nevertheless, one great hurdle of NeRF-based GANs is the high computation cost, which restricts earlier works [35, 4, 7, 46, 30] from synthesizing high-quality images. Consequently, a large number of follow-up works [25, 9, 53, 48, 27, 3, 47] avoid rendering NeRF at high resolution by conducting 2D super-resolution from a low-resolution image or feature map rendered by NeRF-like fields. This is only a stopgap as the black-box 2D super-resolution module sacrifices the important 3D consistency brought by NeRF. To keep the strict 3D consistency, several works [6, 45, 36, 41, 52] turn to more sparse 3D representations such as sparse voxel [36], radiance manifolds [6], and multi-plane images [52] to allow direct rendering at high resolution. Carefully designed training strategies such as two-stage training [45] or patch-wise optimization [41] are also introduced to facilitate the learning process. However, their image generation quality still lags behind those with 2D super-resolution. Our method combines the advantages of both lines of works to achieve high-quality image generation and strict 3D consistency at once, by leveraging the proposed 3D-to-2D imitation.", + "bbox": [ + 76, + 90, + 472, + 500 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3D generation by 3D-to-2D imitation. Recent studies [13, 37, 10] reveal that 2D generative models [2, 17] have the ability to generate pseudo multiview images of a subject. Based on this observation, several methods [28, 51, 38, 29] propose to distill the knowledge from a pretrained 2D generative model for 3D generation by performing 3D reconstruction on the generated \"multiview\" images. A standard procedure is to render the 3D representation of an object from multiple views, and compare them with the closest samples falling in the latent space of the pre-trained 2D generator for iterative optimization. The 2D generator ensures that the rendered results are photorealistic from different views, meanwhile the intrinsic property of the 3D representation guarantees reasonable 3D structure, thus leading to high-quality 3D generation. Some recent methods [32, 19] also combine this idea with text-to-image diffusion models [33, 34] to achieve text-driven 3D creation. Our method shares a similar spirit, which distills the knowledge from the generator's 2D super-resolution branch to its 3D rendering branch, thus achieving image generation with both photorealism and strict 3D consistency.", + "bbox": [ + 76, + 511, + 472, + 829 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Approach", + "text_level": 1, + "bbox": [ + 76, + 844, + 187, + 861 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Given a collection of 2D images, we aim to learn a 3D-aware generator $G$ for free-view image synthesis. The gen", + "bbox": [ + 76, + 869, + 468, + 902 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "erator takes a random code $z \\in \\mathbb{R}^{d_z}$ and an explicit camera pose $\\theta \\in \\mathbb{R}^{d_{\\theta}}$ as input, and generates a 2D image $I$ :", + "bbox": [ + 498, + 90, + 890, + 122 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nG: (\\boldsymbol {z}, \\boldsymbol {\\theta}) \\in \\mathbb {R} ^ {d _ {z}} \\times \\mathbb {R} ^ {d _ {\\theta}} \\rightarrow I \\in \\mathbb {R} ^ {H \\times W \\times 3}. \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 550, + 130, + 890, + 148 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To enable high-quality image synthesis, we adopt EG3D [3] as the backbone of the generator, which synthesizes low-resolution feature fields via the tri-plane representation [3], and leverages 2D super-resolution for high-resolution image generation (Sec. 3.1). Based on EG3D, we propose a 3D-to-2D imitation strategy to synthesize high-resolution NeRF for 3D-consistent image rendering. We leverage a 3D super-resolution branch to predict high-resolution triplanes from the low-resolution ones, and force the rendered images from the former to mimic the images generated by the 2D super-resolution branch (Sec. 3.2). In addition, we introduce 3D-aware convolution [44] to the generator for better tri-plane learning via cross-plane communications, which helps to further improve the image generation quality (Sec. 3.3). The overview of our method is illustrated in Fig. 3. We describe each part in detail below.", + "bbox": [ + 496, + 159, + 893, + 402 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Preliminaries: EG3D", + "text_level": 1, + "bbox": [ + 500, + 410, + 700, + 425 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "EG3D adopts a StyleGAN2-based [18] generator $\\mathcal{E}$ to efficiently synthesize the low-resolution feature field of a subject. The feature field is represented by the tri-plane representation which consists of three orthogonal 2D planes produced by reshaping the output feature map of $\\mathcal{E}$ , given the latent code $z$ as input. For a point $\\pmb{x} \\in \\mathbb{R}^3$ in the 3D space, its corresponding feature $\\mathbf{f}$ can be obtained by projecting itself onto the three planes $\\mathbf{P}_{xy}, \\mathbf{P}_{yz}, \\mathbf{P}_{zx}$ , and summing the retrieved features $\\mathbf{f}_{xy}, \\mathbf{f}_{yz}, \\mathbf{f}_{zx}$ . A small MLP $\\mathcal{M}$ then maps this intermediate feature to volume density $\\sigma \\in \\mathbb{R}$ and color feature $\\pmb{c} \\in \\mathbb{R}^{d_c}$ (the first three dimensions represent RGB color), forming the low-resolution feature field:", + "bbox": [ + 496, + 433, + 890, + 614 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {M}: \\mathbf {f} \\in \\mathbb {R} ^ {d ^ {\\mathbf {f}}} \\rightarrow (c, \\sigma) \\in \\mathbb {R} ^ {d ^ {c}} \\times \\mathbb {R}. \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 576, + 625, + 890, + 643 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "To generate high-resolution images, EG3D enforces volume rendering [14, 23] to render the above feature field to a low-resolution feature map $C$ , where each pixel value $C(\\boldsymbol{r})$ corresponding to a viewing ray $\\boldsymbol{r}$ can be obtained via", + "bbox": [ + 496, + 648, + 890, + 710 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nC (\\boldsymbol {r}) = \\sum_ {i = 1} ^ {N} T _ {i} (1 - \\exp (- \\sigma_ {i} \\delta_ {i})) \\boldsymbol {c} _ {i}, T _ {i} = \\exp (- \\sum_ {j = 1} ^ {i - 1} \\sigma_ {j} \\delta_ {j}). \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 506, + 718, + 890, + 757 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Here, $i$ is the index of points along ray $r$ sorted from near to far, and $\\delta$ is the distance between adjacent points. Then, the rendered feature map $C$ is sent to a 2D super-resolution module $S^{2D}$ consisting of several StyleGAN2-modulated convolutional layers to generate the final image $I^{2D}$ .", + "bbox": [ + 496, + 763, + 890, + 840 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Although EG3D can generate free-view images of high quality, it cannot well maintain their 3D consistency across different views. This is inevitable due to incorporating the black-box CNN-based 2D super-resolution mod", + "bbox": [ + 496, + 840, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "2340", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/73f98d857ddebfbcedb1e09800685ca779ed89a8f976f62879b902a03cc5138b.jpg", + "image_caption": [ + "Figure 3. Overview of our framework. 3D-to-2D imitation strategy is enforced to let the generator's 3D branch to mimic the results of its 2D branch, thus leading to image generation of high quality and strict 3D consistency. 3D-aware convolutions are also introduced to the tri-plane generator to enhance 3D representation learning, which further improves the image generation quality." + ], + "image_footnote": [], + "bbox": [ + 86, + 89, + 885, + 289 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "ule, which breaks the physical rules of the volume rendering process. Despite that EG3D further proposes a dual-discrimination [3] strategy to force the high-resolution images to be consistent with their low-resolution counterparts, detail-level 3D inconsistency (i.e. texture flickering) still cannot be eliminated. During continuous camera variation, these artifacts can be easily captured by human eyes, differing the synthesized results from a real video sequence. To maintain the 3D consistency meanwhile keep the high-quality image generation to the maximum extent, we propose a 3D-to-2D imitation strategy described below.", + "bbox": [ + 75, + 358, + 472, + 525 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. 3D-to-2D Imitation", + "text_level": 1, + "bbox": [ + 76, + 534, + 261, + 549 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To keep the strict 3D consistency, a better way is to directly render the 3D representation instead of resorting to a 2D CNN for image synthesis. Noticing that the images generated by EG3D contain rich details, it is natural to use them as guidance for images synthesized by direct 3D rendering. If the directly-rendered images well mimic those fine details, their quality should get very close to that of EG3D. Meanwhile, since they are rendered from a continuous 3D representation, their 3D consistency across different views should be trivially maintained. This motivates us to design the 3D-to-2D imitation strategy, as depicted in Fig. 3.", + "bbox": [ + 75, + 558, + 468, + 724 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Specifically, we introduce a 3D super-resolution module $S^{3D}$ to generate residual tri-planes $\\mathbf{P}^r$ from the coarse tri-planes $\\mathbf{P}^c$ produced by the tri-plane generator $\\mathcal{E}$ :", + "bbox": [ + 75, + 724, + 468, + 770 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {S} ^ {3 D}: \\mathbf {P} ^ {c} \\in \\mathbb {R} ^ {3 \\times H ^ {c} \\times W ^ {c} \\times d ^ {\\mathbf {f}}} \\rightarrow \\mathbf {P} ^ {r} \\in \\mathbb {R} ^ {3 \\times H ^ {r} \\times W ^ {r} \\times d ^ {\\mathbf {f}}}. \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 96, + 779, + 468, + 799 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The $S^{3D}$ adopts several StyleGAN2-modulated convolutional layers conditioned on a latent code $\\pmb{w}$ mapped from the random code $\\pmb{z}$ , similar to the 2D super-resolution module $S^{2D}$ in EG3D. The difference is that $S^{3D}$ conducts super-resolution on the triplane-based 3D representation instead of the rendered 2D feature map. In this way, we can", + "bbox": [ + 75, + 808, + 470, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "generate a high-resolution 3D field for direct 3D rendering. Given the coarse and residual tri-planes (i.e. $\\mathbf{P}^c$ and $\\mathbf{P}^r$ ), we obtain a more detailed intermediate feature $\\mathbf{f} = \\mathbf{f}^c + \\mathbf{f}^r$ for a 3D point $x$ , and further obtain the high-resolution feature field by sending the intermediate feature into the MLP-based decoder $\\mathcal{M}$ following Eq. (2). The first three feature dimensions of the field derive the high-resolution NeRF for rendering 3D-consistent fine image $I^{3D}$ via Eq. (3).", + "bbox": [ + 496, + 358, + 890, + 479 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "To ensure that $I^{3D}$ contains reasonable geometry structure with rich texture details, we let it to mimic the contents of $I^{2D}$ generated by the 2D branch $S^{2D}$ . For a pair of $I^{3D}$ and $I^{2D}$ synthesized with the same latent code $z$ and camera pose $\\theta$ , we enforce imitation loss between them to guarantee their perceptual similarity:", + "bbox": [ + 496, + 484, + 892, + 575 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {i m i t a t i o n}} = \\operatorname {L P I P S} \\left(I ^ {3 D}, \\operatorname {s g} \\left(I ^ {2 D}\\right)\\right), \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 570, + 599, + 890, + 617 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathrm{LPIPS}(\\cdot ,\\cdot)$ is the perceptual loss defined in [49], and sg denotes stopping gradient to avoid undesired influence of $I^{3D}$ on the 2D branch. This process is very similar to a standard multiview reconstruction process. During training, $I^{2D}$ sharing the same code $\\mathbf{z}$ are generated under different camera views from a statistical aspect, forming the multiview supervision. The high-resolution NeRF from the 3D branch renders $I^{3D}$ under the same camera views to compare with the multiview data for 3D reconstruction. Considering that $I^{2D}$ are nearly 3D-consistent, they should help to learn a reasonable NeRF for 3D-consistent image rendering.", + "bbox": [ + 496, + 637, + 892, + 803 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Nevertheless, since $I^{2D}$ are not strictly 3D-consistent, faithfully reconstructing their image contents leads to blurry results where the texture details across different views are averaged out. Therefore, we further introduce the non-saturating GAN loss with R1 regularization [21] between $I^{3D}$ and real images $\\hat{I}$ to maintain the high-frequency de", + "bbox": [ + 496, + 809, + 893, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "2341", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "tails:", + "bbox": [ + 76, + 90, + 112, + 103 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {L} _ {a d v} ^ {3 D} = \\mathbb {E} _ {\\boldsymbol {z} \\sim p _ {z}, \\boldsymbol {\\theta} \\sim p _ {\\theta}} [ f (D ^ {3 D} (G ^ {3 D} (\\boldsymbol {z}, \\boldsymbol {\\theta}))) ] \\tag {6} \\\\ + \\mathbb {E} _ {\\hat {I} \\sim p _ {r e a l}} [ f (- D ^ {3 D} (\\hat {I})) + \\lambda \\| \\nabla D ^ {3 D} (\\hat {I})) \\| ^ {2} ], \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 89, + 112, + 468, + 154 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $f(u) = \\log (1 + \\exp (u))$ is the Softplus function, $G^{3D}$ including $\\{\\mathcal{E},\\mathcal{M},\\mathcal{S}^{3D}\\}$ is the 3D rendering branch of the generator, and $D^{3D}$ is the corresponding discriminator.", + "bbox": [ + 76, + 160, + 468, + 205 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "An advantage of the above imitation learning is that we can render small patches (i.e. $64 \\times 64$ ) to compute Eq. (5) and Eq. (6), as shown in Fig. 3, with only minor influence to the final image quality. This largely reduces the memory cost during training and enables learning the 3D branch at high resolution (e.g. $512 \\times 512$ ). By contrast, solely applying adversarial loss at patch-level often leads to large quality drops as shown in previous methods [35, 41] and Tab. 2.", + "bbox": [ + 75, + 205, + 468, + 325 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Finally, we apply image-level adversarial loss to the 2D branch following EG3D to ensure that $I^{2D}$ , as the supervision for the 3D branch, are of high quality:", + "bbox": [ + 75, + 327, + 468, + 372 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {L} _ {a d v} ^ {2 D} = \\mathbb {E} _ {\\boldsymbol {z} \\sim p _ {z}, \\boldsymbol {\\theta} \\sim p _ {\\theta}} [ f (D ^ {2 D} (G ^ {2 D} (\\boldsymbol {z}, \\boldsymbol {\\theta}))) ] \\tag {7} \\\\ + \\mathbb {E} _ {I \\sim p _ {r e a l}} [ f (- D ^ {2 D} (\\hat {I})) + \\lambda \\| \\nabla D ^ {2 D} (\\hat {I})) \\| ^ {2} ], \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 89, + 393, + 468, + 434 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $G^{2D}$ is the 2D branch generator consisting of $\\{\\mathcal{E},\\mathcal{M},\\mathcal{S}^{2D}\\}$ , and $D^{2D}$ is the corresponding discriminator. The same dual discrimination is adopted as done in EG3D.", + "bbox": [ + 76, + 440, + 468, + 486 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Overall, the training objective is", + "bbox": [ + 96, + 487, + 313, + 501 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\text {i m i t a t i o n}} + \\mathcal {L} _ {\\text {a d v}} ^ {3 D} + \\mathcal {L} _ {\\text {a d v}} ^ {2 D}. \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 148, + 510, + 468, + 529 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "In practice, we first learn the 2D branch via $\\mathcal{L}_{adv}^{2D}$ to obtain reasonable synthesized images $I^{2D}$ , then leverage $\\mathcal{L}_{total}$ to simultaneously learn the 2D and 3D branches for high-quality and 3D-consistent image synthesis.", + "bbox": [ + 75, + 535, + 468, + 597 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.3. 3D-Aware Tri-Plane Generator", + "text_level": 1, + "bbox": [ + 76, + 604, + 352, + 619 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "As depicted in Sec. 3.2, the tri-plane generator $\\mathcal{E}$ is responsible for synthesizing the coarse tri-planes $\\mathbf{P}^c$ shared by both the 2D and 3D branches, which is an important component that would affect the final image generation quality. However, in EG3D, $\\mathcal{E}$ takes a StyleGAN2 architecture originally designed for 2D generative tasks. As shown in Fig. 4(a), the original tri-plane generator only contains the main stream and the output stream. The tri-planes are obtained from latent feature maps in the main stream via 2D convolutions (i.e. toRGB layers), and the latent feature maps are also produced by a serials of 2D synthesis blocks. Consequently, the latent feature maps are forced to learn 3D unaligned features of the three orthogonal planes and the latters also lack feature communications with each other. Inspired by a recent 3D diffusion model [44], we introduce 3D-aware convolutions into our tri-plane generator $\\mathcal{E}$ to enhance feature communications between 3D-associated positions across different planes, for better tri-plane generation.", + "bbox": [ + 75, + 628, + 468, + 900 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/70f80d0b4d1fceca7c9ccc518d9a3bf59cdca62cfbbad2b6ca2e50532f003be3.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 506, + 88, + 864, + 234 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/d96d7a3b654a58ecadfc4215cbb0d516c8587ee41a74d2cd7ce571f163e4bbb8.jpg", + "image_caption": [ + "Figure 4. (a) Structure of our 3D-aware tri-plane generator. (b) Operations of the 3D-aware block on $xy$ plane." + ], + "image_footnote": [], + "bbox": [ + 500, + 239, + 888, + 367 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Specifically, as illustrated in Fig. 4(a), we add an extra 3D-aware stream upon the original output stream after each toRGB layer at different resolutions. At each resolution level $k$ , the corresponding tri-planes $\\mathbf{P}_k = [\\mathbf{P}_{k,xy},\\mathbf{P}_{k,yz},\\mathbf{P}_{k,zx}]$ , are summed with the tri-planes produced by the original output stream, and further sent into a 3D-aware block to produce tri-plane features for the next level. The 3D-aware block conducts similar operations on each of the three planes. For brevity, we omit the subscript $k$ here and take $\\mathbf{P}_{xy}$ as an example to illustrate the operation process. As shown in Fig. 4(b), to align $\\mathbf{P}_{yz}$ and $\\mathbf{P}_{zx}$ towards $\\mathbf{P}_{xy}$ , we first perform global pooling along $z$ axis of the former two to obtain $z$ -squeezed feature vectors. These vectors are then repeated along the $z$ dimension to restore the original spatial size, denoted as $\\mathbf{P}_{yr}$ and $\\mathbf{P}_{rx}$ . In this manner, the obtained $\\mathbf{P}_{yr}$ and $\\mathbf{P}_{rx}$ are aligned with $\\mathbf{P}_{xy}$ from a 3D perspective, i.e., a 2D position $uv$ on $\\mathbf{P}_{xy}$ is responsible for features in region $uvz, z \\in [z_{min}, z_{max}]$ in the 3D space, meanwhile the same $uv$ position on $\\mathbf{P}_{yr}$ and $\\mathbf{P}_{rx}$ also associate with the features in this 3D region. As a result, we can simply concatenate them along the channel dimension as $[\\mathbf{P}_{xy},\\mathbf{P}_{yr},\\mathbf{P}_{rx}]$ , and perform modulated 2D convolution [18] on it. The 2D convolution aggregates the 3D-associated features to produce next-level $\\mathbf{P}_{xy}$ , leading to better feature communications across the planes. $\\mathbf{P}_{yz}$ and $\\mathbf{P}_{zx}$ can be processed similarly.", + "bbox": [ + 496, + 430, + 892, + 823 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Note that in [44], the 3D-aware convolution is applied in all layers in a U-Net structure. However, in our scenario, leveraging 3D-aware convolution for all layers, especially the main stream, introduces unaffordable memory cost during training, as it would produce multiple auxiliary tensors", + "bbox": [ + 496, + 824, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "2342", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/9b710f27b2d8d9add99a85e353e11d3b1a178adb62dc7a5dff1aecaa3ea1be49.jpg", + "image_caption": [ + "EG3D" + ], + "image_footnote": [], + "bbox": [ + 80, + 102, + 475, + 304 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/330f4b7d46f9e0a6aa6ea432c37745412866796eebf6c97f4b9ca11b112a85e3.jpg", + "image_caption": [ + "Ours (3D branch)", + "Figure 5. Comparison between our method and EG3D on FFHQ at $512 \\times 512$ resolution. Our method generates images with comparable quality to those of EG3D, while producing 3D geometries with finer details and multiview sequences with better 3D-consistency." + ], + "image_footnote": [], + "bbox": [ + 496, + 102, + 888, + 304 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/6668d0c6ba3449c6a90f57a81e805ab39799784708cf66b7c208a41a3cf405a8.jpg", + "image_caption": [ + "GMPI" + ], + "image_footnote": [], + "bbox": [ + 81, + 362, + 349, + 431 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/144f4379c2bf7de7bfede9eb56f646ce71bc5594da7032ad790d416ac3f7e749.jpg", + "image_caption": [ + "EpiGRAF", + "Figure 6. Comparison between our method and other 3D rendering baselines on FFHQ at $512 \\times 512$ resolution. Best viewed with zoom-in." + ], + "image_footnote": [], + "bbox": [ + 351, + 362, + 619, + 431 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/f12d8146a65bc2ede645a372ed80dbeae1ab3ec63075360e29ed3b8f42fd1f73.jpg", + "image_caption": [ + "Ours (3D branch)" + ], + "image_footnote": [], + "bbox": [ + 620, + 362, + 888, + 431 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "and triples the channel dimension for each processed latent feature map, as shown in Fig. 4(b). Comparing to the latent feature maps in the main stream, the tri-planes after each output layer contains much fewer channels thus more memory-friendly to adopt the 3D-aware convolution. Empirically, our proposed 3D-aware stream helps to learn more reasonable tri-planes and improves the final image generation quality, with only a minor increase in the total memory consumption (see Sec. 4.3).", + "bbox": [ + 75, + 476, + 468, + 612 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experiments", + "text_level": 1, + "bbox": [ + 76, + 631, + 209, + 648 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Implementation details. We train our method on two real-world datasets: FFHQ [17] and AFHQ-v2 Cats [5], which consists of 70K human face images of $1024^2$ resolution and 5.5K cat face images of $512^2$ resolution, respectively. We follow the data pre-processing of EG3D [3] to crop and resize the images to $256^2$ or $512^2$ resolution. Experiments are conducted on 8 NVIDIA Tesla A100 GPUs with 40GB memory, following the training configuration of EG3D. For FFHQ, the training process takes around 8 days, where learning the 2D branch takes 5 days and jointly training the whole framework takes additional 3 days. For AFHQ-v2, we finetune the 2D branch initially trained on FFHQ for 1 day, then jointly train the whole framework for extra 3 days. Adaptive data augmentation [15] is applied to AFHQ-v2 to facilitate training with limited data. See the suppl. material for more details.", + "bbox": [ + 75, + 657, + 470, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Visual Results", + "text_level": 1, + "bbox": [ + 500, + 474, + 643, + 489 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Figure 2 shows the multiview images generated by our 3D branch generator. It can produce high-quality images with fine details at a resolution of $512^2$ . Moreover, the images are of strict 3D consistency across different views via directly rendering the generated high-resolution NeRF. More results are in Fig. 5, 6, and the suppl. material.", + "bbox": [ + 498, + 500, + 892, + 590 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Comparison with Prior Arts", + "text_level": 1, + "bbox": [ + 500, + 599, + 754, + 616 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Baselines. We compare our method with existing 3D-aware GANs, including methods leveraging 2D superresolution: StyleSDF [27], VolumeGAN [47], StyleN-erF [9], and EG3D [3]; and methods with direct 3D rendering: GRAM [6], GRAM-HD [45], GMPI [52], EpiGRAF [41], and VoxGRAF [36].", + "bbox": [ + 498, + 623, + 890, + 715 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Qualitative comparison. Figure 5 shows the visual comparison between our method and EG3D. Our generated images via direct rendering have comparable quality with those generated by EG3D via 2D super-resolution. We further visualize the 3D geometry and the spatiotemporal texture images [45] of the two methods. The geometry is extracted via Marching Cubes [20] on the density field at $512^{3}$ resolution. The spatiotemporal textures are obtained by stacking the pixels of a fixed line segment under continuous camera change, very similar to the Epipolar Line Images [1], where smoothly tilted strips indicate better 3D", + "bbox": [ + 496, + 734, + 893, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "2343", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/3e29e00a0d7ba11da4356e06373a73e824983c25fb3f2fa154d4418a9868f6e1.jpg", + "table_caption": [], + "table_footnote": [ + "Table 1. Comparison on image generation quality and 3D consistency among different 3D-aware GANs." + ], + "table_body": "
MethodFFHQ256FFHQ512CATS256CATS512
FID ↓PSNR\\( _{mv} \\) ↑SSIM\\( _{mv} \\) ↑FID ↓PSNR\\( _{mv} \\) ↑SSIM\\( _{mv} \\) ↑FID ↓FID ↓
w/2D SRStyleSDF [27]11.5--11.2---7.91
VolumeGAN [47]9.1033.60.926-----
StyleNeRF [9]8.0031.90.9157.8030.90.843--
EG3D [3]4.8034.00.9284.7032.40.8613.882.77
Ours (2D branch)3.9135.70.9384.1433.30.8913.412.72
w/o 2D SRGRAM [6]13.838.00.966---13.4-
GRAM-HD [45]10.436.50.955----7.67
GMPI [52]11.439.80.9778.2939.00.961-7.79
EpiGRAF [41]9.71--9.9237.30.9496.93-
VoxGRAF [36]9.6037.20.960---9.60-
Ours (3D branch)5.1439.30.9745.3737.80.9554.144.29
", + "bbox": [ + 127, + 88, + 844, + 271 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "consistency. As shown, our geometries contain finer details in that we directly learn the NeRF of a subject at high resolution. Our spatiotemporal textures are also more reasonable with fewer twisted patterns, thanks to the direct 3D rendering for image synthesis instead of using a black-box 2D super-resolution module.", + "bbox": [ + 75, + 309, + 468, + 398 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Figure 6 compares our method with other 3D baselines on FFHQ at $512^{2}$ resolution. Visually inspected, our 3D branch produces images of higher fidelity compared to existing methods leveraging direct 3D rendering. More analysis and video results can be found in the suppl. material.", + "bbox": [ + 75, + 401, + 468, + 477 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Quantitative comparison. Table 1 and Fig. 1 show the quantitative results of different methods in terms of image generation quality and 3D consistency. For image generation quality, We calculate the Frechet Inception Distance (FID) [12] between 50K generated images and all available real images in the training set. For 3D consistency, we follow GRAM-HD [45] to generate multiview images of 50 random subjects and train the multiview reconstruction method NeuS [43] on each of them. We report the average PSNR and SSIM scores between our generated multiview images and the re-rendered images of NeuS (denoted as $\\mathrm{PSNR}_{mv}$ and $\\mathrm{SSIM}_{mv}$ ). Theoretically, better 3D consistency facilitates the 3D reconstruction process of NeuS, thus leading to higher PSNR and SSIM.", + "bbox": [ + 75, + 484, + 468, + 696 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "As shown, our 2D branch generator demonstrates better results compared to EG3D in all metrics across different datasets, thanks to our 3D-aware stream in the tri-plane generator. Moreover, with the 3D-to-2D imitation strategy, our 3D branch generator largely improves the image generation quality among methods using direct 3D rendering, while maintaining competitive 3D consistency. Its image quality even surpasses most of the methods with 2D superresolution and comes very close to that of EG3D.", + "bbox": [ + 75, + 698, + 468, + 834 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Ablation Study", + "text_level": 1, + "bbox": [ + 76, + 845, + 230, + 862 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We conduct ablation studies to validate the efficacy of our proposed 3D-to-2D imitation and the 3D-aware tri", + "bbox": [ + 76, + 869, + 468, + 900 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/dee20053f752579b4fe0f1f8ba85f9e0235e955d20e4c60971662284a3bbd56a.jpg", + "table_caption": [], + "table_footnote": [ + "Table 2. Ablation study on 3D-to-2D imitation strategy." + ], + "table_body": "
Label\\( \\mathcal{L}_{\\text{limitation}} \\)\\( \\mathcal{S}^{3D} \\)\\( \\mathcal{L}_{\\text{adv}}^{3D} \\)FID (3D branch)
(A)30.6
(B)✓29.9
(C)✓✓9.29
(D)✓✓22.8
(E)✓✓✓5.14
", + "bbox": [ + 519, + 306, + 874, + 409 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/833fae670dccd3ebb76eefcbee3025926eb4faddbdc58f5eddd41c0b1f80d2ac.jpg", + "image_caption": [ + "(A)" + ], + "image_footnote": [], + "bbox": [ + 504, + 443, + 596, + 520 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/22218623e84f17997f010abacc636b037bbe76e13a23dfac5d225c7a5bb07638.jpg", + "image_caption": [ + "(C)" + ], + "image_footnote": [], + "bbox": [ + 599, + 443, + 689, + 520 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/09da423f0ddfe8a015fd99b3a0ec024205f7d1affa1101add44a0ad2d48cdacd.jpg", + "image_caption": [ + "(D)", + "Figure 7. Generated images under different learning strategies. The labels are consistent with Tab. 2." + ], + "image_footnote": [], + "bbox": [ + 699, + 443, + 794, + 520 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/b4abef14d9aba9aff194d61950270337fb308c6faf33754ceb152a52bd24a6f0.jpg", + "image_caption": [ + "(E)" + ], + "image_footnote": [], + "bbox": [ + 795, + 443, + 885, + 520 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "plane generator. For efficiency, all experiments are conducted on FFHQ dataset at $256^{2}$ resolution.", + "bbox": [ + 498, + 568, + 888, + 598 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "3D-to-2D imitation strategy. As shown in Tab. 2 and Fig. 7, We start from a generator without using the 3D-to-2D imitation and the 3D super-resolution module $S^{3D}$ (setting A), by directly rendering the coarse tri-planes $\\mathbf{P}^c$ for image synthesis. The rendered images in this way are blurry and lack fine details, leading to a high FID score of 30.6. Naively introducing the imitation loss (setting B) to improve the rendered images of $\\mathbf{P}^c$ has minor influence, as the capacity of the coarse tri-planes are limited. Further incorporating the 3D super-resolution module (setting C) effectively releases the potential of the imitation loss and largely improves the image generation quality in terms of FID. However, the rendered images still lack rich details limited by the 3D-inconsistent 2D branch supervisions. Then, if the imitation loss is replaced with the adversarial loss (setting D), the image quality decreases significantly. This is due to that we only render small image patches to compute the corresponding losses for memory consideration. Under this circumstance, the adversarial loss is less", + "bbox": [ + 496, + 613, + 892, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "2344", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/c91a1f654816878646fd5bec7ce55be8e05debe381d5ff69d035d984c7a19aa5.jpg", + "table_caption": [], + "table_footnote": [ + "Table 3. Ablation study on designs of 3D-aware tri-plane generator. The FID scores are from 2D or 3D branch; #Param only considers the tri-plane generator $\\mathcal{E}$ and Mem. indicates the GPU memory cost for generating the coarse tri-planes." + ], + "table_body": "
MethodFID (2D)FID (3D)#ParamMem.
w/o 3D-aware4.806.7129.0M2.3G
3D-aware latentOOMOOM111.7M11.6G
3D-aware tri-plane4.14-32.6M2.4G
3D-aware stream (Ours)3.915.1432.6M2.4G
", + "bbox": [ + 80, + 88, + 467, + 160 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/96d7879c2b5af697e46cfa36f3d6f9753a24cc864d5707dbfb524698677d7a7e.jpg", + "image_caption": [ + "Figure 8. Generated tri-planes with or w/o 3D-aware convolutions." + ], + "image_footnote": [], + "bbox": [ + 80, + 226, + 467, + 534 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "stable compared to the imitation loss which is a perceptual-level reconstruction loss. This reveals the advantage of our imitation strategy, which could be extended to higher resolution via patch-wise optimization while maintaining a good image generation quality. Finally, leveraging all the three components (setting E) yields the best result, where the imitation loss keeps the overall structure reasonable and the adversarial loss helps with fine details learning.", + "bbox": [ + 75, + 573, + 468, + 694 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "3D-aware tri-plane generator. Table 3 shows the ablation study on the 3D-aware tri-plane generator. We compare our design with two alternatives and one without 3D-aware convolutions originally adopted by EG3D. We report the parameter size of the tri-plane generators, the inference memory cost to generate the coarse tri-planes, as well as the final image generation quality in terms of FID. In the first alternative, we remove our 3D-aware stream, and leverage 3D-aware convolutions for the latent feature maps in the main stream, namely 3D-aware latent. Since the main stream feature maps have relatively larger feature channels, and the 3D-aware convolution requires to concatenate two additional tensors with the same size as the input tensor, this", + "bbox": [ + 75, + 703, + 470, + 900 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "design increases the parameter size and memory consumption significantly, and raises the out-of-memory issue during training. In the second alternative, namely 3D-aware tri-plane, we directly apply 3D-aware convolutions in the output stream, by inserting them after the upsampling operations at each resolution, instead of using the additional 3D-aware stream. This strategy leads to an improvement of the image generation quality of the 2D branch, and largely reduces the parameter size and memory cost compare to the first design. Finally, our 3D-aware stream design further improves the image generation quality without introducing extra parameters and memory costs. Therefore, we adopt it as our final 3D-aware tri-plane generator for 3D-to-2D imitation. It effectively lowers the FID score of both the 2D and 3D branches compared to the original structure without 3D-aware convolutions, with only a minor increase of the parameter size and memory cost.", + "bbox": [ + 496, + 90, + 890, + 347 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Figure 8 further shows the synthesized tri-planes, where we visualize the L2 norm of each spatial location on the three orthogonal planes. Our method leveraging the 3D-aware stream produces more informative tri-planes. The generated planes of the side-views better depict the characters of different instances (e.g., see the difference of the profiles on the $yz$ planes). Our frontal planes (i.e. $xy$ planes) also demonstrate more clear head silhouettes compared to those without using the 3D-aware convolutions.", + "bbox": [ + 496, + 347, + 890, + 483 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusions", + "text_level": 1, + "bbox": [ + 500, + 497, + 625, + 512 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We presented a novel learning strategy for 3D-aware GANs to achieve image synthesis of high quality and strict 3D consistency. The core idea is to enforce the images synthesized by the generator's 3D rendering branch to mimic those generated by its 2D super-resolution branch. We also introduced 3D-aware convolutions to the generator to further improve the image generation quality. With the above strategies, our method largely improves the image quality among methods using direct 3D rendering, which we believe enables a new way for more realistic 3D generation.", + "bbox": [ + 496, + 522, + 890, + 674 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Limitation and future works. Our method has several limitations. The image generation quality of its 3D branch still lags behind that of the 2D branch. Certain generated 3D structures such as hairs and cat whiskers are stuck to the geometry surfaces instead of correctly floating in the volumetric space. The 3D-to-2D imitation strategy also introduces extra training time and memory costs compared to only learning the 2D branch. We expect more effective learning strategies and more advanced 3D representations to alleviate these problems.", + "bbox": [ + 496, + 681, + 890, + 832 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Ethics consideration. The goal of this paper is to generate images of virtual subjects. It is not intended for creating misleading or deceptive contents of real people and we do not condone any such harmful behavior.", + "bbox": [ + 496, + 839, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "2345", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Robert C Bolles, H Harlyn Baker, and David H Marimont. Epipolar-plane image analysis: An approach to determining structure from motion. International journal of computer vision, 1(1):7-55, 1987. 6", + "[2] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale GAN training for high fidelity natural image synthesis. In Proceedings of the International Conference on Learning Representations, 2019. 3", + "[3] Eric R Chan, Connor Z Lin, Matthew A Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas Guibas, Jonathan Tremblay, Sameh Khamis, et al. Efficient geometry-aware 3D generative adversarial networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1, 2, 3, 4, 6, 7", + "[4] Eric R Chan, Marco Monteiro, Petr Kellnhofer, Jiajun Wu, and Gordon Wetzstein. pi-GAN: Periodic implicit generative adversarial networks for 3D-aware image synthesis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. 1, 2, 3", + "[5] Yunjey Choi, Youngjung Uh, Jaejun Yoo, and Jung-Woo Ha. StarGAN v2: Diverse image synthesis for multiple domains. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, 2020. 2, 6", + "[6] Yu Deng, Jiaolong Yang, Jianfeng Xiang, and Xin Tong. GRAM: Generative radiance manifolds for 3D-aware image generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1, 2, 3, 6, 7", + "[7] Terrance DeVries, Miguel Angel Bautista, Nitish Srivastava, Graham W Taylor, and Joshua M Susskind. Unconstrained scene generation with locally conditioned radiance fields. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2021. 3", + "[8] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In Proceedings of the Advances in Neural Information Processing Systems, 2014. 1, 3", + "[9] Jiatao Gu, Lingjie Liu, Peng Wang, and Christian Theobalt. StyleNeRF: A style-based 3D aware generator for high-resolution image synthesis. In Proceedings of the International Conference on Learning Representations, 2022. 1, 2, 3, 6, 7", + "[10] Erik Härkönen, Aaron Hertzmann, Jaakko Lehtinen, and Sylvain Paris. GANSpace: Discovering interpretable GAN controls. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 3", + "[11] Philipp Henzler, Niloy J Mitra, and Tobias Ritschel. Escaping plato's cave: 3D shape from adversarial rendering. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2019. 2, 3", + "[12] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. GANs trained by a two time-scale update rule converge to a local nash equilibrium. In Proceedings of the Advances in Neural Information Processing Systems, 2017. 2, 7" + ], + "bbox": [ + 78, + 114, + 470, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[13] Ali Jahanian, Lucy Chai, and Phillip Isola. On the \"steerability\" of generative adversarial networks. In Proceedings of the International Conference on Learning Representations, 2020. 3", + "[14] James T Kajiya and Brian P Von Herzen. Ray tracing volume densities. ACM SIGGRAPH, 18(3):165-174, 1984. 1, 3", + "[15] Tero Karras, Miika Aittala, Janne Hellsten, Samuli Laine, Jaakko Lehtinen, and Timo Aila. Training generative adversarial networks with limited data. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 6", + "[16] Tero Karras, Miika Aittala, Samuli Laine, Erik Härkönen, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Alias-free generative adversarial networks. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 1", + "[17] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4401-4410, 2019. 2, 3, 6", + "[18] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of styleGAN. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. 1, 3, 5", + "[19] Chen-Hsuan Lin, Jun Gao, Luming Tang, Towaki Takikawa, Xiaohui Zeng, Xun Huang, Karsten Kreis, Sanja Fidler, Ming-Yu Liu, and Tsung-Yi Lin. Magic3D: High-resolution text-to-3D content creation. arXiv:2211.10440, 2022. 3", + "[20] William E Lorensen and Harvey E Cline. Marching cubes: A high resolution 3D surface construction algorithm. ACM SIGGRAPH, 21(4):163-169, 1987. 6", + "[21] Lars Mescheder, Andreas Geiger, and Sebastian Nowozin. Which training methods for GANs do actually converge? In Proceedings of the International Conference on Machine Learning, 2018. 4", + "[22] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3D reconstruction in function space. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. 3", + "[23] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. In Proceedings of the European Conference on Computer Vision, 2020. 1, 3", + "[24] Thu Nguyen-Phuoc, Chuan Li, Lucas Theis, Christian Richardt, and Yong-Liang Yang. Hologan: Unsupervised learning of 3D representations from natural images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7588-7597, 2019. 2, 3", + "[25] Michael Niemeyer and Andreas Geiger. Giraffe: Representing scenes as compositional generative neural feature fields. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11453-11464, 2021. 1, 2, 3", + "[26] Michael Oechsle, Songyou Peng, and Andreas Geiger. Unisurf: Unifying neural implicit surfaces and radiance" + ], + "bbox": [ + 501, + 92, + 893, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "2346", + "bbox": [ + 482, + 944, + 516, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "fields for multi-view reconstruction. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2021. 3", + "[27] Roy Or-El, Xuan Luo, Mengyi Shan, Eli Shechtman, Jeong Joon Park, and Ira Kemelmacher-Shlizerman. StyleSDF: High-resolution 3D-consistent image and geometry generation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2022. 1, 3, 6, 7", + "[28] Xingang Pan, Bo Dai, Ziwei Liu, Chen Change Loy, and Ping Luo. Do 2D GANs know 3D shape? unsupervised 3D shape reconstruction from 2d image gans. In Proceedings of the International Conference on Learning Representations, 2021. 2, 3", + "[29] Xingang Pan, Ayush Tewari, Lingjie Liu, and Christian Theobalt. Gan2x: Non-lambertian inverse rendering of image gans. In Proceedings of the International Conference on 3D Vision, 2022. 3", + "[30] Xingang Pan, Xudong Xu, Chen Change Loy, Christian Theobalt, and Bo Dai. A shading-guided generative implicit model for shape-accurate 3D-aware image synthesis. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 3", + "[31] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. DeepSDF: Learning continuous signed distance functions for shape representation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. 3", + "[32] Ben Poole, Ajay Jain, Jonathan T Barron, and Ben Mildenhall. Dreamfusion: Text-to-3D using 2D diffusion. arXiv:2209.14988, 2022. 2, 3", + "[33] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 3", + "[34] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Raphael Gontijo-Lopes, Burcu Karagol Ayan, Tim Salimans, et al. Photorealistic text-to-image diffusion models with deep language understanding. In Proceedings of the Advances in Neural Information Processing Systems, 2022. 3", + "[35] Katja Schwarz, Yiyi Liao, Michael Niemeyer, and Andreas Geiger. GRAF: Generative radiance fields for 3D-aware image synthesis. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 1, 2, 3, 5", + "[36] Katja Schwarz, Axel Sauer, Michael Niemeyer, Yiyi Liao, and Andreas Geiger. VoxGRAF: Fast 3D-aware image synthesis with sparse voxel grids. In Proceedings of the Advances in Neural Information Processing Systems, 2022. 1, 3, 6, 7", + "[37] Yujun Shen, Jinjin Gu, Xiaou Tang, and Bolei Zhou. Interpreting the latent space of GANs for semantic face editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. 3", + "[38] Yichun Shi, Divyansh Aggarwal, and Anil K Jain. Lifting 2D StyleGAN for 3D-aware face generation. In Proceedings of" + ], + "bbox": [ + 78, + 90, + 470, + 901 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. 3", + "[39] Vincent Sitzmann, Julien Martel, Alexander Bergman, David Lindell, and Gordon Wetzstein. Implicit neural representations with periodic activation functions. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 3", + "[40] Vincent Sitzmann, Michael Zollhöfer, and Gordon Wetzstein. Scene representation networks: continuous 3D-structure-aware neural scene representations. In Proceedings of the Advances in Neural Information Processing Systems, 2019. 3", + "[41] Ivan Skorokhodov, Sergey Tulyakov, Yiqun Wang, and Peter Wonka. EpiGRAF: Rethinking training of 3D GANs. In Proceedings of the Advances in Neural Information Processing Systems, 2022. 1, 2, 3, 5, 6, 7", + "[42] Attila Szabó, Givi Meishvili, and Paolo Favaro. Unsupervised generative 3D shape learning from natural images. arXiv:1910.00287, 2019. 3", + "[43] Peng Wang, Lingjie Liu, Yuan Liu, Christian Theobalt, Taku Komura, and Wenping Wang. NeuS: Learning neural implicit surfaces by volume rendering for multi-view reconstruction. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 1, 3, 7", + "[44] Tengfei Wang, Bo Zhang, Ting Zhang, Shuyang Gu, Jianmin Bao, Tadas Baltrusaitis, Jingjing Shen, Dong Chen, Fang Wen, Qifeng Chen, et al. Rodin: A generative model for sculpting 3D digital avatars using diffusion. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, 2023. 2, 3, 5", + "[45] Jianfeng Xiang, Jiaolong Yang, Yu Deng, and Xin Tong. GRAM-HD: 3D-consistent image generation at high resolution with generative radiance manifolds. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2023. 1, 3, 6, 7", + "[46] Xudong Xu, Xingang Pan, Dahua Lin, and Bo Dai. Generative occupancy fields for 3D surface-aware image synthesis. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 3", + "[47] Yinghao Xu, Sida Peng, Ceyuan Yang, Yujun Shen, and Bolei Zhou. 3D-aware image synthesis via learning structural and textural representations. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18430-18439, 2022. 3, 6, 7", + "[48] Yang Xue, Yuheng Li, Krishna Kumar Singh, and Yong Jae Lee. Giraffe HD: A high-resolution 3D-aware generative model. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18440-18449, 2022. 1, 3", + "[49] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2018. 2, 4", + "[50] Xuanmeng Zhang, Zhedong Zheng, Daiheng Gao, Bang Zhang, Pan Pan, and Yi Yang. Multi-view consistent generative adversarial networks for 3D-aware image synthesis." + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "2347", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2", + "[51] Yuxuan Zhang, Wenzheng Chen, Huan Ling, Jun Gao, Yi-nan Zhang, Antonio Torralba, and Sanja Fidler. Image gans meet differentiable rendering for inverse graphics and interpretable 3D neural rendering. In Proceedings of the International Conference on Learning Representations, 2021. 2, 3", + "[52] Xiaoming Zhao, Fangchang Ma, David Guera, Zhile Ren, Alexander G Schwing, and Alex Colburn. Generative multiplane images: Making a 2D GAN 3D-aware. In Proceedings of the European Conference on Computer Vision, 2022. 1, 2, 3, 6, 7", + "[53] Peng Zhou, Lingxi Xie, Bingbing Ni, and Qi Tian. Cips-3d: A 3D-aware generator of gans based on conditionally-independent pixel synthesis. arXiv:2110.09788, 2021. 3" + ], + "bbox": [ + 78, + 90, + 468, + 316 + ], + "page_idx": 10 + }, + { + "type": "page_number", + "text": "2348", + "bbox": [ + 482, + 945, + 514, + 955 + ], + "page_idx": 10 + } +] \ No newline at end of file diff --git a/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/d009dfab-0a08-423e-b77c-b88a4b5cf703_model.json b/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/d009dfab-0a08-423e-b77c-b88a4b5cf703_model.json new file mode 100644 index 0000000000000000000000000000000000000000..47e9749bdf65255367b0c06a31c1d3a4e2e8a33e --- /dev/null +++ b/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/d009dfab-0a08-423e-b77c-b88a4b5cf703_model.json @@ -0,0 +1,2158 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.182, + 0.131, + 0.79, + 0.152 + ], + "angle": 0, + "content": "Mimic3D: Thriving 3D-Aware GANs via 3D-to-2D Imitation" + }, + { + "type": "text", + "bbox": [ + 0.304, + 0.181, + 0.666, + 0.218 + ], + "angle": 0, + "content": "Xingyu Chen* Yu Deng* Baoyuan Wang Xiaobing.AI" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.252, + 0.314, + 0.267 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.283, + 0.473, + 0.631 + ], + "angle": 0, + "content": "Generating images with both photorealism and multiview 3D consistency is crucial for 3D-aware GANs, yet existing methods struggle to achieve them simultaneously. Improving the photorealism via CNN-based 2D super-resolution can break the strict 3D consistency, while keeping the 3D consistency by learning high-resolution 3D representations for direct rendering often compromises image quality. In this paper, we propose a novel learning strategy, namely 3D-to-2D imitation, which enables a 3D-aware GAN to generate high-quality images while maintaining their strict 3D consistency, by letting the images synthesized by the generator's 3D rendering branch mimic those generated by its 2D super-resolution branch. We also introduce 3D-aware convolutions into the generator for better 3D representation learning, which further improves the image generation quality. With the above strategies, our method reaches FID scores of 5.4 and 4.3 on FFHQ and AFHQ-v2 Cats, respectively, at \\(512 \\times 512\\) resolution, largely outperforming existing 3D-aware GANs using direct 3D rendering and coming very close to the previous state-of-the-art method that leverages 2D super-resolution. Project website: https://seancheny.github.io/Mimic3DWeb." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.658, + 0.208, + 0.673 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.683, + 0.47, + 0.88 + ], + "angle": 0, + "content": "3D-aware GANs [35, 9, 6, 3] have experienced rapid development in recent years and shown great potential for large-scale realistic 3D content creation. The core of 3D-aware GANs is to incorporate 3D representation learning and differentiable rendering into image-level adversarial learning [8]. In this way, the generated 3D representations are forced to mimic real image distribution from arbitrary viewing angles, resulting in their faithful reconstruction of the underlying 3D structures of the subjects for free-view image synthesis. Among different 3D representations, neural radiance field (NeRF) [23] has been proven to be effective in the 3D-aware GAN scenario [35, 4], which guarantees strong 3D consistency when synthesizing multiview" + }, + { + "type": "image", + "bbox": [ + 0.505, + 0.251, + 0.891, + 0.432 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.434, + 0.893, + 0.56 + ], + "angle": 0, + "content": "Figure 1. Comparison between different 3D-aware GANs on image generation quality and multiview 3D consistency. The image generation quality is evaluated via FID between generated and real images. The 3D consistency is measured by conducting 3D reconstruction [43] on generated multiview images and calculating PSNR between them and the re-rendered reconstruction results. Our method inherits the high image quality of approaches leveraging 2D super-resolution meanwhile maintains strict 3D consistency by taking the advantage of direct 3D rendering." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.593, + 0.731, + 0.608 + ], + "angle": 0, + "content": "images via volume rendering [14]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.61, + 0.893, + 0.732 + ], + "angle": 0, + "content": "However, NeRF's volumetric representation also brings high computation costs to GAN training. This hinders the generative models from synthesizing high-resolution images with fine details. Several attempts have been made to facilitate NeRF-based GAN training at high resolution, via sparse representations [36, 6, 45, 52] or patch-wise adversarial learning [41], yet the performance is still unsatisfactory and lags far behind state-of-the-art 2D GANs [18, 16]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Along another line, instead of using direct NeRF rendering, plenty of works [25, 9, 27, 3, 48] introduce 2D super-resolution module to deal with 3D-aware GAN training at high resolution. A typical procedure is to first render a NeRF-like feature field into low-resolution feature maps, then apply a 2D CNN to generate high-resolution images from them. The representative work among this line, namely EG3D [3], utilizes tri-plane representation to effectively model the low-resolution feature field and leverages StyleGAN2-like [18] super-resolution block to achieve image synthesis at high-quality. It sets a record for image" + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.887, + 0.379, + 0.9 + ], + "angle": 0, + "content": "*These authors have contributed equally to this work." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2338" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.09, + 0.891, + 0.232 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.099, + 0.235, + 0.868, + 0.25 + ], + "angle": 0, + "content": "Figure 2. Our method enables high-quality image generation at \\(512 \\times 512\\) resolution without using a 2D super-resolution module." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.278, + 0.47, + 0.339 + ], + "angle": 0, + "content": "quality among 3D-aware GANs and gets very close to that of state-of-the-art 2D GANs. However, a fatal drawback of this line of works is a sacrifice of strict 3D consistency, due to leveraging a black-box 2D CNN for image synthesis." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.341, + 0.469, + 0.446 + ], + "angle": 0, + "content": "A question naturally arises — Is there any way to combine the above two lines to achieve strict 3D consistency and high-quality image generation simultaneously? The answer, as we will show in this paper, is arguably yes. The key intuition is to let the images synthesized by direct NeRF rendering to mimic those generated by a 2D superresolution module, which we name 3D-to-2D imitation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.448, + 0.471, + 0.901 + ], + "angle": 0, + "content": "Specifically, we start from an EG3D backbone that adopts 2D super-resolution to generate high-resolution images from a low-resolution feature field. Based on this architecture, we add another 3D super-resolution module to generate high-resolution NeRF from the low-resolution feature field and force the images rendered by the former to imitate those generated by the 2D super-resolution branch. This process can be seen as a multiview reconstruction process — images sharing the same latent code from different views produced by the 2D branch are pseudo multiview data, and the high-resolution NeRF branch represents the 3D scene to be reconstructed. Previous methods [28, 51, 32] have shown that this procedure can obtain reasonable 3D reconstruction, even if the multiview data are not strictly 3D consistent. We believe this is partially due to the inductive bias (e.g., continuity and sparsity) of the underlying 3D representation. With the above process, the high-resolution NeRF learns to depict fine details of the 2D-branch images, thus enabling high-quality image rendering. The 3D consistency across different views can also be preserved thanks to the intrinsic property of NeRF. Note that if the rendered images try to faithfully reconstruct every detail of the 2D-branch images across different views, it is likely to obtain blurry results due to detail-level 3D inconsistency of the latter. To avoid this problem, we only let the images produced by the two branches be perceptually similar (i.e. by LPIPS loss [49]), and further enforce adversarial loss between the rendered images from the high-resolution NeRF and real images to maintain high-frequency details. In addition, we only render small image patches to conduct the imitative" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.278, + 0.722, + 0.293 + ], + "angle": 0, + "content": "learning to reduce memory costs." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.295, + 0.892, + 0.552 + ], + "angle": 0, + "content": "Apart from the above learning strategy, we introduce 3D-aware convolutions to the EG3D backbone to improve tri-plane learning, motivated by a recent 3D diffusion model [44]. The original EG3D generates tri-plane features to model the low-resolution feature field via a StyleGAN2-like generator. The generator is forced to learn 2D-unaligned features on the three orthogonal planes via 2D convolutions, which is inefficient. The 3D-aware convolution considers associated features in 3D space when performing 2D convolution, which improves feature communications and helps to produce more reasonable tri-planes. Nevertheless, directly applying 3D-aware convolution in all layers in the generator is unaffordable. As a result, we only apply them after the output layers at each resolution in the tri-plane generator. This helps us to further improve the image generation quality with only a minor increase in the total memory consumption." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.554, + 0.893, + 0.781 + ], + "angle": 0, + "content": "With the above strategies, our generator is able to synthesize 3D-consistent images of virtual subjects with high image quality (Fig. 2). It reaches FID scores [12] of 5.4 and 4.3 on FFHQ [17] and AFHQ-v2 Cats [5], respectively, at \\(512 \\times 512\\) resolution, largely outperforming previous 3D-aware GANs with direct 3D rendering and even surpassing many leveraging 2D super-resolution (Fig. 1). A by-product of our method is a more powerful 2D-branch generator, which reaches an FID of 4.1 on FFHQ, exceeding previous state-of-the-art EG3D. Though our method presented in this paper is mostly based on EG3D backbone, its 3D-to-2D imitation strategy can be extended to learning other 3D-aware GANs as well. We believe this would largely close the quality gap between 3D-aware GANs and traditional 2D GANs, and pave a new way for realistic 3D generation." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.799, + 0.651, + 0.814 + ], + "angle": 0, + "content": "2. Related Works" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.903 + ], + "angle": 0, + "content": "3D-aware GAN. 3D-aware GANs [11, 24, 35, 4, 25, 9, 50, 6, 3, 41, 52] aim to generate multiview images of an object category, given only in-the-wild 2D images as training data. The key is to represent the generated scenes via a 3D representation and leverage corresponding rendering" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2339" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.473, + 0.501 + ], + "angle": 0, + "content": "techniques to synthesize images at different viewpoints for image-level adversarial learning [8]. Initially, explicit representations such as voxels [24, 11] and meshes [42] are used to describe scenes. With the development of neural implicit fields [31, 22, 40, 39, 23, 43, 26], implicit scene representations, especially NeRF [23], gradually overtake explicit ones in 3D-aware GANs [4, 27, 3]. Nevertheless, one great hurdle of NeRF-based GANs is the high computation cost, which restricts earlier works [35, 4, 7, 46, 30] from synthesizing high-quality images. Consequently, a large number of follow-up works [25, 9, 53, 48, 27, 3, 47] avoid rendering NeRF at high resolution by conducting 2D super-resolution from a low-resolution image or feature map rendered by NeRF-like fields. This is only a stopgap as the black-box 2D super-resolution module sacrifices the important 3D consistency brought by NeRF. To keep the strict 3D consistency, several works [6, 45, 36, 41, 52] turn to more sparse 3D representations such as sparse voxel [36], radiance manifolds [6], and multi-plane images [52] to allow direct rendering at high resolution. Carefully designed training strategies such as two-stage training [45] or patch-wise optimization [41] are also introduced to facilitate the learning process. However, their image generation quality still lags behind those with 2D super-resolution. Our method combines the advantages of both lines of works to achieve high-quality image generation and strict 3D consistency at once, by leveraging the proposed 3D-to-2D imitation." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.512, + 0.473, + 0.83 + ], + "angle": 0, + "content": "3D generation by 3D-to-2D imitation. Recent studies [13, 37, 10] reveal that 2D generative models [2, 17] have the ability to generate pseudo multiview images of a subject. Based on this observation, several methods [28, 51, 38, 29] propose to distill the knowledge from a pretrained 2D generative model for 3D generation by performing 3D reconstruction on the generated \"multiview\" images. A standard procedure is to render the 3D representation of an object from multiple views, and compare them with the closest samples falling in the latent space of the pre-trained 2D generator for iterative optimization. The 2D generator ensures that the rendered results are photorealistic from different views, meanwhile the intrinsic property of the 3D representation guarantees reasonable 3D structure, thus leading to high-quality 3D generation. Some recent methods [32, 19] also combine this idea with text-to-image diffusion models [33, 34] to achieve text-driven 3D creation. Our method shares a similar spirit, which distills the knowledge from the generator's 2D super-resolution branch to its 3D rendering branch, thus achieving image generation with both photorealism and strict 3D consistency." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.845, + 0.188, + 0.862 + ], + "angle": 0, + "content": "3. Approach" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.871, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Given a collection of 2D images, we aim to learn a 3D-aware generator \\( G \\) for free-view image synthesis. The gen" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.123 + ], + "angle": 0, + "content": "erator takes a random code \\(z \\in \\mathbb{R}^{d_z}\\) and an explicit camera pose \\(\\theta \\in \\mathbb{R}^{d_{\\theta}}\\) as input, and generates a 2D image \\(I\\):" + }, + { + "type": "equation", + "bbox": [ + 0.552, + 0.131, + 0.892, + 0.15 + ], + "angle": 0, + "content": "\\[\nG: (\\boldsymbol {z}, \\boldsymbol {\\theta}) \\in \\mathbb {R} ^ {d _ {z}} \\times \\mathbb {R} ^ {d _ {\\theta}} \\rightarrow I \\in \\mathbb {R} ^ {H \\times W \\times 3}. \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.16, + 0.895, + 0.403 + ], + "angle": 0, + "content": "To enable high-quality image synthesis, we adopt EG3D [3] as the backbone of the generator, which synthesizes low-resolution feature fields via the tri-plane representation [3], and leverages 2D super-resolution for high-resolution image generation (Sec. 3.1). Based on EG3D, we propose a 3D-to-2D imitation strategy to synthesize high-resolution NeRF for 3D-consistent image rendering. We leverage a 3D super-resolution branch to predict high-resolution triplanes from the low-resolution ones, and force the rendered images from the former to mimic the images generated by the 2D super-resolution branch (Sec. 3.2). In addition, we introduce 3D-aware convolution [44] to the generator for better tri-plane learning via cross-plane communications, which helps to further improve the image generation quality (Sec. 3.3). The overview of our method is illustrated in Fig. 3. We describe each part in detail below." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.411, + 0.702, + 0.426 + ], + "angle": 0, + "content": "3.1. Preliminaries: EG3D" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.434, + 0.892, + 0.616 + ], + "angle": 0, + "content": "EG3D adopts a StyleGAN2-based [18] generator \\(\\mathcal{E}\\) to efficiently synthesize the low-resolution feature field of a subject. The feature field is represented by the tri-plane representation which consists of three orthogonal 2D planes produced by reshaping the output feature map of \\(\\mathcal{E}\\), given the latent code \\(z\\) as input. For a point \\(\\pmb{x} \\in \\mathbb{R}^3\\) in the 3D space, its corresponding feature \\(\\mathbf{f}\\) can be obtained by projecting itself onto the three planes \\(\\mathbf{P}_{xy}, \\mathbf{P}_{yz}, \\mathbf{P}_{zx}\\), and summing the retrieved features \\(\\mathbf{f}_{xy}, \\mathbf{f}_{yz}, \\mathbf{f}_{zx}\\). A small MLP \\(\\mathcal{M}\\) then maps this intermediate feature to volume density \\(\\sigma \\in \\mathbb{R}\\) and color feature \\(\\pmb{c} \\in \\mathbb{R}^{d_c}\\) (the first three dimensions represent RGB color), forming the low-resolution feature field:" + }, + { + "type": "equation", + "bbox": [ + 0.577, + 0.625, + 0.892, + 0.645 + ], + "angle": 0, + "content": "\\[\n\\mathcal {M}: \\mathbf {f} \\in \\mathbb {R} ^ {d ^ {\\mathbf {f}}} \\rightarrow (c, \\sigma) \\in \\mathbb {R} ^ {d ^ {c}} \\times \\mathbb {R}. \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.65, + 0.892, + 0.711 + ], + "angle": 0, + "content": "To generate high-resolution images, EG3D enforces volume rendering [14, 23] to render the above feature field to a low-resolution feature map \\(C\\), where each pixel value \\(C(\\boldsymbol{r})\\) corresponding to a viewing ray \\(\\boldsymbol{r}\\) can be obtained via" + }, + { + "type": "equation", + "bbox": [ + 0.507, + 0.719, + 0.892, + 0.758 + ], + "angle": 0, + "content": "\\[\nC (\\boldsymbol {r}) = \\sum_ {i = 1} ^ {N} T _ {i} (1 - \\exp (- \\sigma_ {i} \\delta_ {i})) \\boldsymbol {c} _ {i}, T _ {i} = \\exp (- \\sum_ {j = 1} ^ {i - 1} \\sigma_ {j} \\delta_ {j}). \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.892, + 0.841 + ], + "angle": 0, + "content": "Here, \\(i\\) is the index of points along ray \\(r\\) sorted from near to far, and \\(\\delta\\) is the distance between adjacent points. Then, the rendered feature map \\(C\\) is sent to a 2D super-resolution module \\(S^{2D}\\) consisting of several StyleGAN2-modulated convolutional layers to generate the final image \\(I^{2D}\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.841, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Although EG3D can generate free-view images of high quality, it cannot well maintain their 3D consistency across different views. This is inevitable due to incorporating the black-box CNN-based 2D super-resolution mod" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2340" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.087, + 0.09, + 0.887, + 0.29 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.293, + 0.895, + 0.337 + ], + "angle": 0, + "content": "Figure 3. Overview of our framework. 3D-to-2D imitation strategy is enforced to let the generator's 3D branch to mimic the results of its 2D branch, thus leading to image generation of high quality and strict 3D consistency. 3D-aware convolutions are also introduced to the tri-plane generator to enhance 3D representation learning, which further improves the image generation quality." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.359, + 0.473, + 0.526 + ], + "angle": 0, + "content": "ule, which breaks the physical rules of the volume rendering process. Despite that EG3D further proposes a dual-discrimination [3] strategy to force the high-resolution images to be consistent with their low-resolution counterparts, detail-level 3D inconsistency (i.e. texture flickering) still cannot be eliminated. During continuous camera variation, these artifacts can be easily captured by human eyes, differing the synthesized results from a real video sequence. To maintain the 3D consistency meanwhile keep the high-quality image generation to the maximum extent, we propose a 3D-to-2D imitation strategy described below." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.535, + 0.262, + 0.55 + ], + "angle": 0, + "content": "3.2. 3D-to-2D Imitation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.559, + 0.47, + 0.725 + ], + "angle": 0, + "content": "To keep the strict 3D consistency, a better way is to directly render the 3D representation instead of resorting to a 2D CNN for image synthesis. Noticing that the images generated by EG3D contain rich details, it is natural to use them as guidance for images synthesized by direct 3D rendering. If the directly-rendered images well mimic those fine details, their quality should get very close to that of EG3D. Meanwhile, since they are rendered from a continuous 3D representation, their 3D consistency across different views should be trivially maintained. This motivates us to design the 3D-to-2D imitation strategy, as depicted in Fig. 3." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.725, + 0.47, + 0.771 + ], + "angle": 0, + "content": "Specifically, we introduce a 3D super-resolution module \\(S^{3D}\\) to generate residual tri-planes \\(\\mathbf{P}^r\\) from the coarse tri-planes \\(\\mathbf{P}^c\\) produced by the tri-plane generator \\(\\mathcal{E}\\):" + }, + { + "type": "equation", + "bbox": [ + 0.097, + 0.78, + 0.47, + 0.8 + ], + "angle": 0, + "content": "\\[\n\\mathcal {S} ^ {3 D}: \\mathbf {P} ^ {c} \\in \\mathbb {R} ^ {3 \\times H ^ {c} \\times W ^ {c} \\times d ^ {\\mathbf {f}}} \\rightarrow \\mathbf {P} ^ {r} \\in \\mathbb {R} ^ {3 \\times H ^ {r} \\times W ^ {r} \\times d ^ {\\mathbf {f}}}. \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.809, + 0.471, + 0.903 + ], + "angle": 0, + "content": "The \\(S^{3D}\\) adopts several StyleGAN2-modulated convolutional layers conditioned on a latent code \\(\\pmb{w}\\) mapped from the random code \\(\\pmb{z}\\), similar to the 2D super-resolution module \\(S^{2D}\\) in EG3D. The difference is that \\(S^{3D}\\) conducts super-resolution on the triplane-based 3D representation instead of the rendered 2D feature map. In this way, we can" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.359, + 0.892, + 0.48 + ], + "angle": 0, + "content": "generate a high-resolution 3D field for direct 3D rendering. Given the coarse and residual tri-planes (i.e. \\(\\mathbf{P}^c\\) and \\(\\mathbf{P}^r\\)), we obtain a more detailed intermediate feature \\(\\mathbf{f} = \\mathbf{f}^c + \\mathbf{f}^r\\) for a 3D point \\(x\\), and further obtain the high-resolution feature field by sending the intermediate feature into the MLP-based decoder \\(\\mathcal{M}\\) following Eq. (2). The first three feature dimensions of the field derive the high-resolution NeRF for rendering 3D-consistent fine image \\(I^{3D}\\) via Eq. (3)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.485, + 0.893, + 0.577 + ], + "angle": 0, + "content": "To ensure that \\( I^{3D} \\) contains reasonable geometry structure with rich texture details, we let it to mimic the contents of \\( I^{2D} \\) generated by the 2D branch \\( S^{2D} \\). For a pair of \\( I^{3D} \\) and \\( I^{2D} \\) synthesized with the same latent code \\( z \\) and camera pose \\( \\theta \\), we enforce imitation loss between them to guarantee their perceptual similarity:" + }, + { + "type": "equation", + "bbox": [ + 0.571, + 0.6, + 0.892, + 0.618 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {i m i t a t i o n}} = \\operatorname {L P I P S} \\left(I ^ {3 D}, \\operatorname {s g} \\left(I ^ {2 D}\\right)\\right), \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.638, + 0.893, + 0.804 + ], + "angle": 0, + "content": "where \\(\\mathrm{LPIPS}(\\cdot ,\\cdot)\\) is the perceptual loss defined in [49], and sg denotes stopping gradient to avoid undesired influence of \\(I^{3D}\\) on the 2D branch. This process is very similar to a standard multiview reconstruction process. During training, \\(I^{2D}\\) sharing the same code \\(\\mathbf{z}\\) are generated under different camera views from a statistical aspect, forming the multiview supervision. The high-resolution NeRF from the 3D branch renders \\(I^{3D}\\) under the same camera views to compare with the multiview data for 3D reconstruction. Considering that \\(I^{2D}\\) are nearly 3D-consistent, they should help to learn a reasonable NeRF for 3D-consistent image rendering." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.894, + 0.902 + ], + "angle": 0, + "content": "Nevertheless, since \\( I^{2D} \\) are not strictly 3D-consistent, faithfully reconstructing their image contents leads to blurry results where the texture details across different views are averaged out. Therefore, we further introduce the non-saturating GAN loss with R1 regularization [21] between \\( I^{3D} \\) and real images \\( \\hat{I} \\) to maintain the high-frequency de" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "2341" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.078, + 0.092, + 0.114, + 0.104 + ], + "angle": 0, + "content": "tails:" + }, + { + "type": "equation", + "bbox": [ + 0.091, + 0.113, + 0.47, + 0.155 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {L} _ {a d v} ^ {3 D} = \\mathbb {E} _ {\\boldsymbol {z} \\sim p _ {z}, \\boldsymbol {\\theta} \\sim p _ {\\theta}} [ f (D ^ {3 D} (G ^ {3 D} (\\boldsymbol {z}, \\boldsymbol {\\theta}))) ] \\tag {6} \\\\ + \\mathbb {E} _ {\\hat {I} \\sim p _ {r e a l}} [ f (- D ^ {3 D} (\\hat {I})) + \\lambda \\| \\nabla D ^ {3 D} (\\hat {I})) \\| ^ {2} ], \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.161, + 0.47, + 0.207 + ], + "angle": 0, + "content": "where \\( f(u) = \\log (1 + \\exp (u)) \\) is the Softplus function, \\( G^{3D} \\) including \\( \\{\\mathcal{E},\\mathcal{M},\\mathcal{S}^{3D}\\} \\) is the 3D rendering branch of the generator, and \\( D^{3D} \\) is the corresponding discriminator." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.207, + 0.469, + 0.327 + ], + "angle": 0, + "content": "An advantage of the above imitation learning is that we can render small patches (i.e. \\(64 \\times 64\\)) to compute Eq. (5) and Eq. (6), as shown in Fig. 3, with only minor influence to the final image quality. This largely reduces the memory cost during training and enables learning the 3D branch at high resolution (e.g. \\(512 \\times 512\\)). By contrast, solely applying adversarial loss at patch-level often leads to large quality drops as shown in previous methods [35, 41] and Tab. 2." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.328, + 0.469, + 0.373 + ], + "angle": 0, + "content": "Finally, we apply image-level adversarial loss to the 2D branch following EG3D to ensure that \\( I^{2D} \\), as the supervision for the 3D branch, are of high quality:" + }, + { + "type": "equation", + "bbox": [ + 0.091, + 0.394, + 0.47, + 0.435 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {L} _ {a d v} ^ {2 D} = \\mathbb {E} _ {\\boldsymbol {z} \\sim p _ {z}, \\boldsymbol {\\theta} \\sim p _ {\\theta}} [ f (D ^ {2 D} (G ^ {2 D} (\\boldsymbol {z}, \\boldsymbol {\\theta}))) ] \\tag {7} \\\\ + \\mathbb {E} _ {I \\sim p _ {r e a l}} [ f (- D ^ {2 D} (\\hat {I})) + \\lambda \\| \\nabla D ^ {2 D} (\\hat {I})) \\| ^ {2} ], \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.441, + 0.47, + 0.487 + ], + "angle": 0, + "content": "where \\(G^{2D}\\) is the 2D branch generator consisting of \\(\\{\\mathcal{E},\\mathcal{M},\\mathcal{S}^{2D}\\}\\), and \\(D^{2D}\\) is the corresponding discriminator. The same dual discrimination is adopted as done in EG3D." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.488, + 0.314, + 0.502 + ], + "angle": 0, + "content": "Overall, the training objective is" + }, + { + "type": "equation", + "bbox": [ + 0.15, + 0.511, + 0.469, + 0.53 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\text {i m i t a t i o n}} + \\mathcal {L} _ {\\text {a d v}} ^ {3 D} + \\mathcal {L} _ {\\text {a d v}} ^ {2 D}. \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.536, + 0.469, + 0.598 + ], + "angle": 0, + "content": "In practice, we first learn the 2D branch via \\(\\mathcal{L}_{adv}^{2D}\\) to obtain reasonable synthesized images \\(I^{2D}\\), then leverage \\(\\mathcal{L}_{total}\\) to simultaneously learn the 2D and 3D branches for high-quality and 3D-consistent image synthesis." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.606, + 0.353, + 0.621 + ], + "angle": 0, + "content": "3.3. 3D-Aware Tri-Plane Generator" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.629, + 0.47, + 0.901 + ], + "angle": 0, + "content": "As depicted in Sec. 3.2, the tri-plane generator \\(\\mathcal{E}\\) is responsible for synthesizing the coarse tri-planes \\(\\mathbf{P}^c\\) shared by both the 2D and 3D branches, which is an important component that would affect the final image generation quality. However, in EG3D, \\(\\mathcal{E}\\) takes a StyleGAN2 architecture originally designed for 2D generative tasks. As shown in Fig. 4(a), the original tri-plane generator only contains the main stream and the output stream. The tri-planes are obtained from latent feature maps in the main stream via 2D convolutions (i.e. toRGB layers), and the latent feature maps are also produced by a serials of 2D synthesis blocks. Consequently, the latent feature maps are forced to learn 3D unaligned features of the three orthogonal planes and the latters also lack feature communications with each other. Inspired by a recent 3D diffusion model [44], we introduce 3D-aware convolutions into our tri-plane generator \\(\\mathcal{E}\\) to enhance feature communications between 3D-associated positions across different planes, for better tri-plane generation." + }, + { + "type": "image", + "bbox": [ + 0.508, + 0.089, + 0.865, + 0.235 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.501, + 0.24, + 0.89, + 0.368 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.372, + 0.892, + 0.402 + ], + "angle": 0, + "content": "Figure 4. (a) Structure of our 3D-aware tri-plane generator. (b) Operations of the 3D-aware block on \\( xy \\) plane." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.431, + 0.893, + 0.824 + ], + "angle": 0, + "content": "Specifically, as illustrated in Fig. 4(a), we add an extra 3D-aware stream upon the original output stream after each toRGB layer at different resolutions. At each resolution level \\( k \\), the corresponding tri-planes \\( \\mathbf{P}_k = [\\mathbf{P}_{k,xy},\\mathbf{P}_{k,yz},\\mathbf{P}_{k,zx}] \\), are summed with the tri-planes produced by the original output stream, and further sent into a 3D-aware block to produce tri-plane features for the next level. The 3D-aware block conducts similar operations on each of the three planes. For brevity, we omit the subscript \\( k \\) here and take \\( \\mathbf{P}_{xy} \\) as an example to illustrate the operation process. As shown in Fig. 4(b), to align \\( \\mathbf{P}_{yz} \\) and \\( \\mathbf{P}_{zx} \\) towards \\( \\mathbf{P}_{xy} \\), we first perform global pooling along \\( z \\) axis of the former two to obtain \\( z \\)-squeezed feature vectors. These vectors are then repeated along the \\( z \\) dimension to restore the original spatial size, denoted as \\( \\mathbf{P}_{yr} \\) and \\( \\mathbf{P}_{rx} \\). In this manner, the obtained \\( \\mathbf{P}_{yr} \\) and \\( \\mathbf{P}_{rx} \\) are aligned with \\( \\mathbf{P}_{xy} \\) from a 3D perspective, i.e., a 2D position \\( uv \\) on \\( \\mathbf{P}_{xy} \\) is responsible for features in region \\( uvz, z \\in [z_{min}, z_{max}] \\) in the 3D space, meanwhile the same \\( uv \\) position on \\( \\mathbf{P}_{yr} \\) and \\( \\mathbf{P}_{rx} \\) also associate with the features in this 3D region. As a result, we can simply concatenate them along the channel dimension as \\( [\\mathbf{P}_{xy},\\mathbf{P}_{yr},\\mathbf{P}_{rx}] \\), and perform modulated 2D convolution [18] on it. The 2D convolution aggregates the 3D-associated features to produce next-level \\( \\mathbf{P}_{xy} \\), leading to better feature communications across the planes. \\( \\mathbf{P}_{yz} \\) and \\( \\mathbf{P}_{zx} \\) can be processed similarly." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.825, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Note that in [44], the 3D-aware convolution is applied in all layers in a U-Net structure. However, in our scenario, leveraging 3D-aware convolution for all layers, especially the main stream, introduces unaffordable memory cost during training, as it would produce multiple auxiliary tensors" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2342" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.26, + 0.091, + 0.297, + 0.101 + ], + "angle": 0, + "content": "EG3D" + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.103, + 0.476, + 0.305 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.646, + 0.091, + 0.74, + 0.102 + ], + "angle": 0, + "content": "Ours (3D branch)" + }, + { + "type": "image", + "bbox": [ + 0.497, + 0.103, + 0.89, + 0.305 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.308, + 0.893, + 0.337 + ], + "angle": 0, + "content": "Figure 5. Comparison between our method and EG3D on FFHQ at \\(512 \\times 512\\) resolution. Our method generates images with comparable quality to those of EG3D, while producing 3D geometries with finer details and multiview sequences with better 3D-consistency." + }, + { + "type": "image_caption", + "bbox": [ + 0.198, + 0.351, + 0.232, + 0.361 + ], + "angle": 0, + "content": "GMPI" + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.363, + 0.35, + 0.432 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.457, + 0.351, + 0.511, + 0.363 + ], + "angle": 0, + "content": "EpiGRAF" + }, + { + "type": "image", + "bbox": [ + 0.352, + 0.363, + 0.62, + 0.432 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.71, + 0.352, + 0.801, + 0.363 + ], + "angle": 0, + "content": "Ours (3D branch)" + }, + { + "type": "image", + "bbox": [ + 0.622, + 0.363, + 0.889, + 0.433 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.436, + 0.893, + 0.45 + ], + "angle": 0, + "content": "Figure 6. Comparison between our method and other 3D rendering baselines on FFHQ at \\(512 \\times 512\\) resolution. Best viewed with zoom-in." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.477, + 0.47, + 0.613 + ], + "angle": 0, + "content": "and triples the channel dimension for each processed latent feature map, as shown in Fig. 4(b). Comparing to the latent feature maps in the main stream, the tri-planes after each output layer contains much fewer channels thus more memory-friendly to adopt the 3D-aware convolution. Empirically, our proposed 3D-aware stream helps to learn more reasonable tri-planes and improves the final image generation quality, with only a minor increase in the total memory consumption (see Sec. 4.3)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.632, + 0.21, + 0.649 + ], + "angle": 0, + "content": "4. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.659, + 0.471, + 0.901 + ], + "angle": 0, + "content": "Implementation details. We train our method on two real-world datasets: FFHQ [17] and AFHQ-v2 Cats [5], which consists of 70K human face images of \\(1024^2\\) resolution and 5.5K cat face images of \\(512^2\\) resolution, respectively. We follow the data pre-processing of EG3D [3] to crop and resize the images to \\(256^2\\) or \\(512^2\\) resolution. Experiments are conducted on 8 NVIDIA Tesla A100 GPUs with 40GB memory, following the training configuration of EG3D. For FFHQ, the training process takes around 8 days, where learning the 2D branch takes 5 days and jointly training the whole framework takes additional 3 days. For AFHQ-v2, we finetune the 2D branch initially trained on FFHQ for 1 day, then jointly train the whole framework for extra 3 days. Adaptive data augmentation [15] is applied to AFHQ-v2 to facilitate training with limited data. See the suppl. material for more details." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.476, + 0.645, + 0.491 + ], + "angle": 0, + "content": "4.1. Visual Results" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.5, + 0.893, + 0.591 + ], + "angle": 0, + "content": "Figure 2 shows the multiview images generated by our 3D branch generator. It can produce high-quality images with fine details at a resolution of \\(512^2\\). Moreover, the images are of strict 3D consistency across different views via directly rendering the generated high-resolution NeRF. More results are in Fig. 5, 6, and the suppl. material." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.601, + 0.755, + 0.617 + ], + "angle": 0, + "content": "4.2. Comparison with Prior Arts" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.624, + 0.892, + 0.716 + ], + "angle": 0, + "content": "Baselines. We compare our method with existing 3D-aware GANs, including methods leveraging 2D superresolution: StyleSDF [27], VolumeGAN [47], StyleN-erF [9], and EG3D [3]; and methods with direct 3D rendering: GRAM [6], GRAM-HD [45], GMPI [52], EpiGRAF [41], and VoxGRAF [36]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.735, + 0.895, + 0.901 + ], + "angle": 0, + "content": "Qualitative comparison. Figure 5 shows the visual comparison between our method and EG3D. Our generated images via direct rendering have comparable quality with those generated by EG3D via 2D super-resolution. We further visualize the 3D geometry and the spatiotemporal texture images [45] of the two methods. The geometry is extracted via Marching Cubes [20] on the density field at \\(512^{3}\\) resolution. The spatiotemporal textures are obtained by stacking the pixels of a fixed line segment under continuous camera change, very similar to the Epipolar Line Images [1], where smoothly tilted strips indicate better 3D" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2343" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.128, + 0.089, + 0.845, + 0.272 + ], + "angle": 0, + "content": "
MethodFFHQ256FFHQ512CATS256CATS512
FID ↓PSNR\\( _{mv} \\) ↑SSIM\\( _{mv} \\) ↑FID ↓PSNR\\( _{mv} \\) ↑SSIM\\( _{mv} \\) ↑FID ↓FID ↓
w/2D SRStyleSDF [27]11.5--11.2---7.91
VolumeGAN [47]9.1033.60.926-----
StyleNeRF [9]8.0031.90.9157.8030.90.843--
EG3D [3]4.8034.00.9284.7032.40.8613.882.77
Ours (2D branch)3.9135.70.9384.1433.30.8913.412.72
w/o 2D SRGRAM [6]13.838.00.966---13.4-
GRAM-HD [45]10.436.50.955----7.67
GMPI [52]11.439.80.9778.2939.00.961-7.79
EpiGRAF [41]9.71--9.9237.30.9496.93-
VoxGRAF [36]9.6037.20.960---9.60-
Ours (3D branch)5.1439.30.9745.3737.80.9554.144.29
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.176, + 0.272, + 0.794, + 0.285 + ], + "angle": 0, + "content": "Table 1. Comparison on image generation quality and 3D consistency among different 3D-aware GANs." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.31, + 0.47, + 0.4 + ], + "angle": 0, + "content": "consistency. As shown, our geometries contain finer details in that we directly learn the NeRF of a subject at high resolution. Our spatiotemporal textures are also more reasonable with fewer twisted patterns, thanks to the direct 3D rendering for image synthesis instead of using a black-box 2D super-resolution module." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.402, + 0.47, + 0.478 + ], + "angle": 0, + "content": "Figure 6 compares our method with other 3D baselines on FFHQ at \\(512^{2}\\) resolution. Visually inspected, our 3D branch produces images of higher fidelity compared to existing methods leveraging direct 3D rendering. More analysis and video results can be found in the suppl. material." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.486, + 0.47, + 0.698 + ], + "angle": 0, + "content": "Quantitative comparison. Table 1 and Fig. 1 show the quantitative results of different methods in terms of image generation quality and 3D consistency. For image generation quality, We calculate the Frechet Inception Distance (FID) [12] between 50K generated images and all available real images in the training set. For 3D consistency, we follow GRAM-HD [45] to generate multiview images of 50 random subjects and train the multiview reconstruction method NeuS [43] on each of them. We report the average PSNR and SSIM scores between our generated multiview images and the re-rendered images of NeuS (denoted as \\(\\mathrm{PSNR}_{mv}\\) and \\(\\mathrm{SSIM}_{mv}\\)). Theoretically, better 3D consistency facilitates the 3D reconstruction process of NeuS, thus leading to higher PSNR and SSIM." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.699, + 0.47, + 0.835 + ], + "angle": 0, + "content": "As shown, our 2D branch generator demonstrates better results compared to EG3D in all metrics across different datasets, thanks to our 3D-aware stream in the tri-plane generator. Moreover, with the 3D-to-2D imitation strategy, our 3D branch generator largely improves the image generation quality among methods using direct 3D rendering, while maintaining competitive 3D consistency. Its image quality even surpasses most of the methods with 2D superresolution and comes very close to that of EG3D." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.847, + 0.231, + 0.863 + ], + "angle": 0, + "content": "4.3. Ablation Study" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.47, + 0.901 + ], + "angle": 0, + "content": "We conduct ablation studies to validate the efficacy of our proposed 3D-to-2D imitation and the 3D-aware tri" + }, + { + "type": "table", + "bbox": [ + 0.52, + 0.307, + 0.875, + 0.41 + ], + "angle": 0, + "content": "
Label\\( \\mathcal{L}_{\\text{limitation}} \\)\\( \\mathcal{S}^{3D} \\)\\( \\mathcal{L}_{\\text{adv}}^{3D} \\)FID (3D branch)
(A)30.6
(B)✓29.9
(C)✓✓9.29
(D)✓✓22.8
(E)✓✓✓5.14
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.531, + 0.41, + 0.862, + 0.423 + ], + "angle": 0, + "content": "Table 2. Ablation study on 3D-to-2D imitation strategy." + }, + { + "type": "image_caption", + "bbox": [ + 0.543, + 0.433, + 0.564, + 0.443 + ], + "angle": 0, + "content": "(A)" + }, + { + "type": "image", + "bbox": [ + 0.506, + 0.444, + 0.597, + 0.521 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.641, + 0.433, + 0.66, + 0.443 + ], + "angle": 0, + "content": "(C)" + }, + { + "type": "image", + "bbox": [ + 0.6, + 0.444, + 0.691, + 0.521 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.738, + 0.433, + 0.756, + 0.443 + ], + "angle": 0, + "content": "(D)" + }, + { + "type": "image", + "bbox": [ + 0.7, + 0.444, + 0.795, + 0.521 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.834, + 0.433, + 0.852, + 0.443 + ], + "angle": 0, + "content": "(E)" + }, + { + "type": "image", + "bbox": [ + 0.796, + 0.444, + 0.887, + 0.521 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.524, + 0.89, + 0.551 + ], + "angle": 0, + "content": "Figure 7. Generated images under different learning strategies. The labels are consistent with Tab. 2." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.569, + 0.89, + 0.599 + ], + "angle": 0, + "content": "plane generator. For efficiency, all experiments are conducted on FFHQ dataset at \\(256^{2}\\) resolution." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.614, + 0.893, + 0.901 + ], + "angle": 0, + "content": "3D-to-2D imitation strategy. As shown in Tab. 2 and Fig. 7, We start from a generator without using the 3D-to-2D imitation and the 3D super-resolution module \\( S^{3D} \\) (setting A), by directly rendering the coarse tri-planes \\( \\mathbf{P}^c \\) for image synthesis. The rendered images in this way are blurry and lack fine details, leading to a high FID score of 30.6. Naively introducing the imitation loss (setting B) to improve the rendered images of \\( \\mathbf{P}^c \\) has minor influence, as the capacity of the coarse tri-planes are limited. Further incorporating the 3D super-resolution module (setting C) effectively releases the potential of the imitation loss and largely improves the image generation quality in terms of FID. However, the rendered images still lack rich details limited by the 3D-inconsistent 2D branch supervisions. Then, if the imitation loss is replaced with the adversarial loss (setting D), the image quality decreases significantly. This is due to that we only render small image patches to compute the corresponding losses for memory consideration. Under this circumstance, the adversarial loss is less" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2344" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.081, + 0.089, + 0.468, + 0.161 + ], + "angle": 0, + "content": "
MethodFID (2D)FID (3D)#ParamMem.
w/o 3D-aware4.806.7129.0M2.3G
3D-aware latentOOMOOM111.7M11.6G
3D-aware tri-plane4.14-32.6M2.4G
3D-aware stream (Ours)3.915.1432.6M2.4G
" + }, + { + "type": "table_footnote", + "bbox": [ + 0.077, + 0.161, + 0.468, + 0.216 + ], + "angle": 0, + "content": "Table 3. Ablation study on designs of 3D-aware tri-plane generator. The FID scores are from 2D or 3D branch; #Param only considers the tri-plane generator \\(\\mathcal{E}\\) and Mem. indicates the GPU memory cost for generating the coarse tri-planes." + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.227, + 0.468, + 0.535 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.078, + 0.54, + 0.468, + 0.553 + ], + "angle": 0, + "content": "Figure 8. Generated tri-planes with or w/o 3D-aware convolutions." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.574, + 0.47, + 0.695 + ], + "angle": 0, + "content": "stable compared to the imitation loss which is a perceptual-level reconstruction loss. This reveals the advantage of our imitation strategy, which could be extended to higher resolution via patch-wise optimization while maintaining a good image generation quality. Finally, leveraging all the three components (setting E) yields the best result, where the imitation loss keeps the overall structure reasonable and the adversarial loss helps with fine details learning." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.704, + 0.471, + 0.901 + ], + "angle": 0, + "content": "3D-aware tri-plane generator. Table 3 shows the ablation study on the 3D-aware tri-plane generator. We compare our design with two alternatives and one without 3D-aware convolutions originally adopted by EG3D. We report the parameter size of the tri-plane generators, the inference memory cost to generate the coarse tri-planes, as well as the final image generation quality in terms of FID. In the first alternative, we remove our 3D-aware stream, and leverage 3D-aware convolutions for the latent feature maps in the main stream, namely 3D-aware latent. Since the main stream feature maps have relatively larger feature channels, and the 3D-aware convolution requires to concatenate two additional tensors with the same size as the input tensor, this" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.348 + ], + "angle": 0, + "content": "design increases the parameter size and memory consumption significantly, and raises the out-of-memory issue during training. In the second alternative, namely 3D-aware tri-plane, we directly apply 3D-aware convolutions in the output stream, by inserting them after the upsampling operations at each resolution, instead of using the additional 3D-aware stream. This strategy leads to an improvement of the image generation quality of the 2D branch, and largely reduces the parameter size and memory cost compare to the first design. Finally, our 3D-aware stream design further improves the image generation quality without introducing extra parameters and memory costs. Therefore, we adopt it as our final 3D-aware tri-plane generator for 3D-to-2D imitation. It effectively lowers the FID score of both the 2D and 3D branches compared to the original structure without 3D-aware convolutions, with only a minor increase of the parameter size and memory cost." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.348, + 0.892, + 0.484 + ], + "angle": 0, + "content": "Figure 8 further shows the synthesized tri-planes, where we visualize the L2 norm of each spatial location on the three orthogonal planes. Our method leveraging the 3D-aware stream produces more informative tri-planes. The generated planes of the side-views better depict the characters of different instances (e.g., see the difference of the profiles on the \\(yz\\) planes). Our frontal planes (i.e. \\(xy\\) planes) also demonstrate more clear head silhouettes compared to those without using the 3D-aware convolutions." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.498, + 0.627, + 0.513 + ], + "angle": 0, + "content": "5. Conclusions" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.523, + 0.892, + 0.675 + ], + "angle": 0, + "content": "We presented a novel learning strategy for 3D-aware GANs to achieve image synthesis of high quality and strict 3D consistency. The core idea is to enforce the images synthesized by the generator's 3D rendering branch to mimic those generated by its 2D super-resolution branch. We also introduced 3D-aware convolutions to the generator to further improve the image generation quality. With the above strategies, our method largely improves the image quality among methods using direct 3D rendering, which we believe enables a new way for more realistic 3D generation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.682, + 0.892, + 0.833 + ], + "angle": 0, + "content": "Limitation and future works. Our method has several limitations. The image generation quality of its 3D branch still lags behind that of the 2D branch. Certain generated 3D structures such as hairs and cat whiskers are stuck to the geometry surfaces instead of correctly floating in the volumetric space. The 3D-to-2D imitation strategy also introduces extra training time and memory costs compared to only learning the 2D branch. We expect more effective learning strategies and more advanced 3D representations to alleviate these problems." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Ethics consideration. The goal of this paper is to generate images of virtual subjects. It is not intended for creating misleading or deceptive contents of real people and we do not condone any such harmful behavior." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "2345" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.47, + 0.171 + ], + "angle": 0, + "content": "[1] Robert C Bolles, H Harlyn Baker, and David H Marimont. Epipolar-plane image analysis: An approach to determining structure from motion. International journal of computer vision, 1(1):7-55, 1987. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.173, + 0.472, + 0.229 + ], + "angle": 0, + "content": "[2] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale GAN training for high fidelity natural image synthesis. In Proceedings of the International Conference on Learning Representations, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.231, + 0.471, + 0.315 + ], + "angle": 0, + "content": "[3] Eric R Chan, Connor Z Lin, Matthew A Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas Guibas, Jonathan Tremblay, Sameh Khamis, et al. Efficient geometry-aware 3D generative adversarial networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1, 2, 3, 4, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.316, + 0.471, + 0.386 + ], + "angle": 0, + "content": "[4] Eric R Chan, Marco Monteiro, Petr Kellnhofer, Jiajun Wu, and Gordon Wetzstein. pi-GAN: Periodic implicit generative adversarial networks for 3D-aware image synthesis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.388, + 0.47, + 0.444 + ], + "angle": 0, + "content": "[5] Yunjey Choi, Youngjung Uh, Jaejun Yoo, and Jung-Woo Ha. StarGAN v2: Diverse image synthesis for multiple domains. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, 2020. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.445, + 0.471, + 0.5 + ], + "angle": 0, + "content": "[6] Yu Deng, Jiaolong Yang, Jianfeng Xiang, and Xin Tong. GRAM: Generative radiance manifolds for 3D-aware image generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1, 2, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.502, + 0.471, + 0.572 + ], + "angle": 0, + "content": "[7] Terrance DeVries, Miguel Angel Bautista, Nitish Srivastava, Graham W Taylor, and Joshua M Susskind. Unconstrained scene generation with locally conditioned radiance fields. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.574, + 0.471, + 0.643 + ], + "angle": 0, + "content": "[8] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In Proceedings of the Advances in Neural Information Processing Systems, 2014. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.645, + 0.47, + 0.713 + ], + "angle": 0, + "content": "[9] Jiatao Gu, Lingjie Liu, Peng Wang, and Christian Theobalt. StyleNeRF: A style-based 3D aware generator for high-resolution image synthesis. In Proceedings of the International Conference on Learning Representations, 2022. 1, 2, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.716, + 0.47, + 0.773 + ], + "angle": 0, + "content": "[10] Erik Härkönen, Aaron Hertzmann, Jaakko Lehtinen, and Sylvain Paris. GANSpace: Discovering interpretable GAN controls. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.774, + 0.47, + 0.829 + ], + "angle": 0, + "content": "[11] Philipp Henzler, Niloy J Mitra, and Tobias Ritschel. Escaping plato's cave: 3D shape from adversarial rendering. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2019. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.831, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[12] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. GANs trained by a two time-scale update rule converge to a local nash equilibrium. In Proceedings of the Advances in Neural Information Processing Systems, 2017. 2, 7" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.472, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.895, + 0.147 + ], + "angle": 0, + "content": "[13] Ali Jahanian, Lucy Chai, and Phillip Isola. On the \"steerability\" of generative adversarial networks. In Proceedings of the International Conference on Learning Representations, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.149, + 0.892, + 0.176 + ], + "angle": 0, + "content": "[14] James T Kajiya and Brian P Von Herzen. Ray tracing volume densities. ACM SIGGRAPH, 18(3):165-174, 1984. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.177, + 0.892, + 0.245 + ], + "angle": 0, + "content": "[15] Tero Karras, Miika Aittala, Janne Hellsten, Samuli Laine, Jaakko Lehtinen, and Timo Aila. Training generative adversarial networks with limited data. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.247, + 0.892, + 0.302 + ], + "angle": 0, + "content": "[16] Tero Karras, Miika Aittala, Samuli Laine, Erik Härkönen, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Alias-free generative adversarial networks. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.302, + 0.892, + 0.37 + ], + "angle": 0, + "content": "[17] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4401-4410, 2019. 2, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.371, + 0.895, + 0.44 + ], + "angle": 0, + "content": "[18] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of styleGAN. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. 1, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.441, + 0.892, + 0.496 + ], + "angle": 0, + "content": "[19] Chen-Hsuan Lin, Jun Gao, Luming Tang, Towaki Takikawa, Xiaohui Zeng, Xun Huang, Karsten Kreis, Sanja Fidler, Ming-Yu Liu, and Tsung-Yi Lin. Magic3D: High-resolution text-to-3D content creation. arXiv:2211.10440, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.497, + 0.892, + 0.538 + ], + "angle": 0, + "content": "[20] William E Lorensen and Harvey E Cline. Marching cubes: A high resolution 3D surface construction algorithm. ACM SIGGRAPH, 21(4):163-169, 1987. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.539, + 0.892, + 0.594 + ], + "angle": 0, + "content": "[21] Lars Mescheder, Andreas Geiger, and Sebastian Nowozin. Which training methods for GANs do actually converge? In Proceedings of the International Conference on Machine Learning, 2018. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.595, + 0.892, + 0.663 + ], + "angle": 0, + "content": "[22] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3D reconstruction in function space. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.664, + 0.892, + 0.734 + ], + "angle": 0, + "content": "[23] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. In Proceedings of the European Conference on Computer Vision, 2020. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.735, + 0.892, + 0.803 + ], + "angle": 0, + "content": "[24] Thu Nguyen-Phuoc, Chuan Li, Lucas Theis, Christian Richardt, and Yong-Liang Yang. Hologan: Unsupervised learning of 3D representations from natural images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7588-7597, 2019. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.804, + 0.892, + 0.871 + ], + "angle": 0, + "content": "[25] Michael Niemeyer and Andreas Geiger. Giraffe: Representing scenes as compositional generative neural feature fields. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11453-11464, 2021. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.873, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[26] Michael Oechsle, Songyou Peng, and Andreas Geiger. Unisurf: Unifying neural implicit surfaces and radiance" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.895, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.517, + 0.956 + ], + "angle": 0, + "content": "2346" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.109, + 0.092, + 0.47, + 0.133 + ], + "angle": 0, + "content": "fields for multi-view reconstruction. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.47, + 0.205 + ], + "angle": 0, + "content": "[27] Roy Or-El, Xuan Luo, Mengyi Shan, Eli Shechtman, Jeong Joon Park, and Ira Kemelmacher-Shlizerman. StyleSDF: High-resolution 3D-consistent image and geometry generation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2022. 1, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.207, + 0.471, + 0.275 + ], + "angle": 0, + "content": "[28] Xingang Pan, Bo Dai, Ziwei Liu, Chen Change Loy, and Ping Luo. Do 2D GANs know 3D shape? unsupervised 3D shape reconstruction from 2d image gans. In Proceedings of the International Conference on Learning Representations, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.278, + 0.47, + 0.332 + ], + "angle": 0, + "content": "[29] Xingang Pan, Ayush Tewari, Lingjie Liu, and Christian Theobalt. Gan2x: Non-lambertian inverse rendering of image gans. In Proceedings of the International Conference on 3D Vision, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.334, + 0.47, + 0.403 + ], + "angle": 0, + "content": "[30] Xingang Pan, Xudong Xu, Chen Change Loy, Christian Theobalt, and Bo Dai. A shading-guided generative implicit model for shape-accurate 3D-aware image synthesis. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.405, + 0.47, + 0.475 + ], + "angle": 0, + "content": "[31] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. DeepSDF: Learning continuous signed distance functions for shape representation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.476, + 0.47, + 0.517 + ], + "angle": 0, + "content": "[32] Ben Poole, Ajay Jain, Jonathan T Barron, and Ben Mildenhall. Dreamfusion: Text-to-3D using 2D diffusion. arXiv:2209.14988, 2022. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.519, + 0.471, + 0.588 + ], + "angle": 0, + "content": "[33] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.59, + 0.47, + 0.685 + ], + "angle": 0, + "content": "[34] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Raphael Gontijo-Lopes, Burcu Karagol Ayan, Tim Salimans, et al. Photorealistic text-to-image diffusion models with deep language understanding. In Proceedings of the Advances in Neural Information Processing Systems, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.688, + 0.47, + 0.743 + ], + "angle": 0, + "content": "[35] Katja Schwarz, Yiyi Liao, Michael Niemeyer, and Andreas Geiger. GRAF: Generative radiance fields for 3D-aware image synthesis. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 1, 2, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.745, + 0.47, + 0.813 + ], + "angle": 0, + "content": "[36] Katja Schwarz, Axel Sauer, Michael Niemeyer, Yiyi Liao, and Andreas Geiger. VoxGRAF: Fast 3D-aware image synthesis with sparse voxel grids. In Proceedings of the Advances in Neural Information Processing Systems, 2022. 1, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.816, + 0.47, + 0.871 + ], + "angle": 0, + "content": "[37] Yujun Shen, Jinjin Gu, Xiaou Tang, and Bolei Zhou. Interpreting the latent space of GANs for semantic face editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.873, + 0.47, + 0.902 + ], + "angle": 0, + "content": "[38] Yichun Shi, Divyansh Aggarwal, and Anil K Jain. Lifting 2D StyleGAN for 3D-aware face generation. In Proceedings of" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.471, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.122, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[39] Vincent Sitzmann, Julien Martel, Alexander Bergman, David Lindell, and Gordon Wetzstein. Implicit neural representations with periodic activation functions. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.193, + 0.892, + 0.261 + ], + "angle": 0, + "content": "[40] Vincent Sitzmann, Michael Zollhöfer, and Gordon Wetzstein. Scene representation networks: continuous 3D-structure-aware neural scene representations. In Proceedings of the Advances in Neural Information Processing Systems, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.264, + 0.892, + 0.319 + ], + "angle": 0, + "content": "[41] Ivan Skorokhodov, Sergey Tulyakov, Yiqun Wang, and Peter Wonka. EpiGRAF: Rethinking training of 3D GANs. In Proceedings of the Advances in Neural Information Processing Systems, 2022. 1, 2, 3, 5, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.321, + 0.892, + 0.361 + ], + "angle": 0, + "content": "[42] Attila Szabó, Givi Meishvili, and Paolo Favaro. Unsupervised generative 3D shape learning from natural images. arXiv:1910.00287, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.364, + 0.892, + 0.433 + ], + "angle": 0, + "content": "[43] Peng Wang, Lingjie Liu, Yuan Liu, Christian Theobalt, Taku Komura, and Wenping Wang. NeuS: Learning neural implicit surfaces by volume rendering for multi-view reconstruction. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 1, 3, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.435, + 0.892, + 0.517 + ], + "angle": 0, + "content": "[44] Tengfei Wang, Bo Zhang, Ting Zhang, Shuyang Gu, Jianmin Bao, Tadas Baltrusaitis, Jingjing Shen, Dong Chen, Fang Wen, Qifeng Chen, et al. Rodin: A generative model for sculpting 3D digital avatars using diffusion. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, 2023. 2, 3, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.519, + 0.892, + 0.587 + ], + "angle": 0, + "content": "[45] Jianfeng Xiang, Jiaolong Yang, Yu Deng, and Xin Tong. GRAM-HD: 3D-consistent image generation at high resolution with generative radiance manifolds. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2023. 1, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.59, + 0.892, + 0.645 + ], + "angle": 0, + "content": "[46] Xudong Xu, Xingang Pan, Dahua Lin, and Bo Dai. Generative occupancy fields for 3D surface-aware image synthesis. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.647, + 0.892, + 0.716 + ], + "angle": 0, + "content": "[47] Yinghao Xu, Sida Peng, Ceyuan Yang, Yujun Shen, and Bolei Zhou. 3D-aware image synthesis via learning structural and textural representations. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18430-18439, 2022. 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.718, + 0.892, + 0.786 + ], + "angle": 0, + "content": "[48] Yang Xue, Yuheng Li, Krishna Kumar Singh, and Yong Jae Lee. Giraffe HD: A high-resolution 3D-aware generative model. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18440-18449, 2022. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.788, + 0.892, + 0.857 + ], + "angle": 0, + "content": "[49] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2018. 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.859, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[50] Xuanmeng Zhang, Zhedong Zheng, Daiheng Gao, Bang Zhang, Pan Pan, and Yi Yang. Multi-view consistent generative adversarial networks for 3D-aware image synthesis." + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "2347" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.47, + 0.12 + ], + "angle": 0, + "content": "In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.47, + 0.202 + ], + "angle": 0, + "content": "[51] Yuxuan Zhang, Wenzheng Chen, Huan Ling, Jun Gao, Yi-nan Zhang, Antonio Torralba, and Sanja Fidler. Image gans meet differentiable rendering for inverse graphics and interpretable 3D neural rendering. In Proceedings of the International Conference on Learning Representations, 2021. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.206, + 0.469, + 0.274 + ], + "angle": 0, + "content": "[52] Xiaoming Zhao, Fangchang Ma, David Guera, Zhile Ren, Alexander G Schwing, and Alex Colburn. Generative multiplane images: Making a 2D GAN 3D-aware. In Proceedings of the European Conference on Computer Vision, 2022. 1, 2, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.277, + 0.469, + 0.318 + ], + "angle": 0, + "content": "[53] Peng Zhou, Lingxi Xie, Bingbing Ni, and Qi Tian. Cips-3d: A 3D-aware generator of gans based on conditionally-independent pixel synthesis. arXiv:2110.09788, 2021. 3" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.318 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.946, + 0.515, + 0.956 + ], + "angle": 0, + "content": "2348" + } + ] +] \ No newline at end of file diff --git a/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/d009dfab-0a08-423e-b77c-b88a4b5cf703_origin.pdf b/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/d009dfab-0a08-423e-b77c-b88a4b5cf703_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..74481855463ff35762da8f66a9cdb61e852d3a7b --- /dev/null +++ b/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/d009dfab-0a08-423e-b77c-b88a4b5cf703_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:f78ffc39f04e4adbde9195388c4a60116e2b7ee56c88cbeba2d534398092b0d5 +size 3140430 diff --git a/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/full.md b/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/full.md new file mode 100644 index 0000000000000000000000000000000000000000..de077173d30ee9f92fcdcf9bb5306f966e2908dd --- /dev/null +++ b/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/full.md @@ -0,0 +1,297 @@ +# Mimic3D: Thriving 3D-Aware GANs via 3D-to-2D Imitation + +Xingyu Chen* Yu Deng* Baoyuan Wang Xiaobing.AI + +# Abstract + +Generating images with both photorealism and multiview 3D consistency is crucial for 3D-aware GANs, yet existing methods struggle to achieve them simultaneously. Improving the photorealism via CNN-based 2D super-resolution can break the strict 3D consistency, while keeping the 3D consistency by learning high-resolution 3D representations for direct rendering often compromises image quality. In this paper, we propose a novel learning strategy, namely 3D-to-2D imitation, which enables a 3D-aware GAN to generate high-quality images while maintaining their strict 3D consistency, by letting the images synthesized by the generator's 3D rendering branch mimic those generated by its 2D super-resolution branch. We also introduce 3D-aware convolutions into the generator for better 3D representation learning, which further improves the image generation quality. With the above strategies, our method reaches FID scores of 5.4 and 4.3 on FFHQ and AFHQ-v2 Cats, respectively, at $512 \times 512$ resolution, largely outperforming existing 3D-aware GANs using direct 3D rendering and coming very close to the previous state-of-the-art method that leverages 2D super-resolution. Project website: https://seancheny.github.io/Mimic3DWeb. + +# 1. Introduction + +3D-aware GANs [35, 9, 6, 3] have experienced rapid development in recent years and shown great potential for large-scale realistic 3D content creation. The core of 3D-aware GANs is to incorporate 3D representation learning and differentiable rendering into image-level adversarial learning [8]. In this way, the generated 3D representations are forced to mimic real image distribution from arbitrary viewing angles, resulting in their faithful reconstruction of the underlying 3D structures of the subjects for free-view image synthesis. Among different 3D representations, neural radiance field (NeRF) [23] has been proven to be effective in the 3D-aware GAN scenario [35, 4], which guarantees strong 3D consistency when synthesizing multiview + +![](images/5d543cc189a12fdc2d92e21927db9373e1468b78ca41ba399cbc799c49479c03.jpg) +Figure 1. Comparison between different 3D-aware GANs on image generation quality and multiview 3D consistency. The image generation quality is evaluated via FID between generated and real images. The 3D consistency is measured by conducting 3D reconstruction [43] on generated multiview images and calculating PSNR between them and the re-rendered reconstruction results. Our method inherits the high image quality of approaches leveraging 2D super-resolution meanwhile maintains strict 3D consistency by taking the advantage of direct 3D rendering. + +images via volume rendering [14]. + +However, NeRF's volumetric representation also brings high computation costs to GAN training. This hinders the generative models from synthesizing high-resolution images with fine details. Several attempts have been made to facilitate NeRF-based GAN training at high resolution, via sparse representations [36, 6, 45, 52] or patch-wise adversarial learning [41], yet the performance is still unsatisfactory and lags far behind state-of-the-art 2D GANs [18, 16]. + +Along another line, instead of using direct NeRF rendering, plenty of works [25, 9, 27, 3, 48] introduce 2D super-resolution module to deal with 3D-aware GAN training at high resolution. A typical procedure is to first render a NeRF-like feature field into low-resolution feature maps, then apply a 2D CNN to generate high-resolution images from them. The representative work among this line, namely EG3D [3], utilizes tri-plane representation to effectively model the low-resolution feature field and leverages StyleGAN2-like [18] super-resolution block to achieve image synthesis at high-quality. It sets a record for image + +![](images/37405ceb46c1fb694d9a2fee9073fbba0c0f776941bdb01c291334cbc2b6acc9.jpg) +Figure 2. Our method enables high-quality image generation at $512 \times 512$ resolution without using a 2D super-resolution module. + +quality among 3D-aware GANs and gets very close to that of state-of-the-art 2D GANs. However, a fatal drawback of this line of works is a sacrifice of strict 3D consistency, due to leveraging a black-box 2D CNN for image synthesis. + +A question naturally arises — Is there any way to combine the above two lines to achieve strict 3D consistency and high-quality image generation simultaneously? The answer, as we will show in this paper, is arguably yes. The key intuition is to let the images synthesized by direct NeRF rendering to mimic those generated by a 2D superresolution module, which we name 3D-to-2D imitation. + +Specifically, we start from an EG3D backbone that adopts 2D super-resolution to generate high-resolution images from a low-resolution feature field. Based on this architecture, we add another 3D super-resolution module to generate high-resolution NeRF from the low-resolution feature field and force the images rendered by the former to imitate those generated by the 2D super-resolution branch. This process can be seen as a multiview reconstruction process — images sharing the same latent code from different views produced by the 2D branch are pseudo multiview data, and the high-resolution NeRF branch represents the 3D scene to be reconstructed. Previous methods [28, 51, 32] have shown that this procedure can obtain reasonable 3D reconstruction, even if the multiview data are not strictly 3D consistent. We believe this is partially due to the inductive bias (e.g., continuity and sparsity) of the underlying 3D representation. With the above process, the high-resolution NeRF learns to depict fine details of the 2D-branch images, thus enabling high-quality image rendering. The 3D consistency across different views can also be preserved thanks to the intrinsic property of NeRF. Note that if the rendered images try to faithfully reconstruct every detail of the 2D-branch images across different views, it is likely to obtain blurry results due to detail-level 3D inconsistency of the latter. To avoid this problem, we only let the images produced by the two branches be perceptually similar (i.e. by LPIPS loss [49]), and further enforce adversarial loss between the rendered images from the high-resolution NeRF and real images to maintain high-frequency details. In addition, we only render small image patches to conduct the imitative + +learning to reduce memory costs. + +Apart from the above learning strategy, we introduce 3D-aware convolutions to the EG3D backbone to improve tri-plane learning, motivated by a recent 3D diffusion model [44]. The original EG3D generates tri-plane features to model the low-resolution feature field via a StyleGAN2-like generator. The generator is forced to learn 2D-unaligned features on the three orthogonal planes via 2D convolutions, which is inefficient. The 3D-aware convolution considers associated features in 3D space when performing 2D convolution, which improves feature communications and helps to produce more reasonable tri-planes. Nevertheless, directly applying 3D-aware convolution in all layers in the generator is unaffordable. As a result, we only apply them after the output layers at each resolution in the tri-plane generator. This helps us to further improve the image generation quality with only a minor increase in the total memory consumption. + +With the above strategies, our generator is able to synthesize 3D-consistent images of virtual subjects with high image quality (Fig. 2). It reaches FID scores [12] of 5.4 and 4.3 on FFHQ [17] and AFHQ-v2 Cats [5], respectively, at $512 \times 512$ resolution, largely outperforming previous 3D-aware GANs with direct 3D rendering and even surpassing many leveraging 2D super-resolution (Fig. 1). A by-product of our method is a more powerful 2D-branch generator, which reaches an FID of 4.1 on FFHQ, exceeding previous state-of-the-art EG3D. Though our method presented in this paper is mostly based on EG3D backbone, its 3D-to-2D imitation strategy can be extended to learning other 3D-aware GANs as well. We believe this would largely close the quality gap between 3D-aware GANs and traditional 2D GANs, and pave a new way for realistic 3D generation. + +# 2. Related Works + +3D-aware GAN. 3D-aware GANs [11, 24, 35, 4, 25, 9, 50, 6, 3, 41, 52] aim to generate multiview images of an object category, given only in-the-wild 2D images as training data. The key is to represent the generated scenes via a 3D representation and leverage corresponding rendering + +techniques to synthesize images at different viewpoints for image-level adversarial learning [8]. Initially, explicit representations such as voxels [24, 11] and meshes [42] are used to describe scenes. With the development of neural implicit fields [31, 22, 40, 39, 23, 43, 26], implicit scene representations, especially NeRF [23], gradually overtake explicit ones in 3D-aware GANs [4, 27, 3]. Nevertheless, one great hurdle of NeRF-based GANs is the high computation cost, which restricts earlier works [35, 4, 7, 46, 30] from synthesizing high-quality images. Consequently, a large number of follow-up works [25, 9, 53, 48, 27, 3, 47] avoid rendering NeRF at high resolution by conducting 2D super-resolution from a low-resolution image or feature map rendered by NeRF-like fields. This is only a stopgap as the black-box 2D super-resolution module sacrifices the important 3D consistency brought by NeRF. To keep the strict 3D consistency, several works [6, 45, 36, 41, 52] turn to more sparse 3D representations such as sparse voxel [36], radiance manifolds [6], and multi-plane images [52] to allow direct rendering at high resolution. Carefully designed training strategies such as two-stage training [45] or patch-wise optimization [41] are also introduced to facilitate the learning process. However, their image generation quality still lags behind those with 2D super-resolution. Our method combines the advantages of both lines of works to achieve high-quality image generation and strict 3D consistency at once, by leveraging the proposed 3D-to-2D imitation. + +3D generation by 3D-to-2D imitation. Recent studies [13, 37, 10] reveal that 2D generative models [2, 17] have the ability to generate pseudo multiview images of a subject. Based on this observation, several methods [28, 51, 38, 29] propose to distill the knowledge from a pretrained 2D generative model for 3D generation by performing 3D reconstruction on the generated "multiview" images. A standard procedure is to render the 3D representation of an object from multiple views, and compare them with the closest samples falling in the latent space of the pre-trained 2D generator for iterative optimization. The 2D generator ensures that the rendered results are photorealistic from different views, meanwhile the intrinsic property of the 3D representation guarantees reasonable 3D structure, thus leading to high-quality 3D generation. Some recent methods [32, 19] also combine this idea with text-to-image diffusion models [33, 34] to achieve text-driven 3D creation. Our method shares a similar spirit, which distills the knowledge from the generator's 2D super-resolution branch to its 3D rendering branch, thus achieving image generation with both photorealism and strict 3D consistency. + +# 3. Approach + +Given a collection of 2D images, we aim to learn a 3D-aware generator $G$ for free-view image synthesis. The gen + +erator takes a random code $z \in \mathbb{R}^{d_z}$ and an explicit camera pose $\theta \in \mathbb{R}^{d_{\theta}}$ as input, and generates a 2D image $I$ : + +$$ +G: (\boldsymbol {z}, \boldsymbol {\theta}) \in \mathbb {R} ^ {d _ {z}} \times \mathbb {R} ^ {d _ {\theta}} \rightarrow I \in \mathbb {R} ^ {H \times W \times 3}. \tag {1} +$$ + +To enable high-quality image synthesis, we adopt EG3D [3] as the backbone of the generator, which synthesizes low-resolution feature fields via the tri-plane representation [3], and leverages 2D super-resolution for high-resolution image generation (Sec. 3.1). Based on EG3D, we propose a 3D-to-2D imitation strategy to synthesize high-resolution NeRF for 3D-consistent image rendering. We leverage a 3D super-resolution branch to predict high-resolution triplanes from the low-resolution ones, and force the rendered images from the former to mimic the images generated by the 2D super-resolution branch (Sec. 3.2). In addition, we introduce 3D-aware convolution [44] to the generator for better tri-plane learning via cross-plane communications, which helps to further improve the image generation quality (Sec. 3.3). The overview of our method is illustrated in Fig. 3. We describe each part in detail below. + +# 3.1. Preliminaries: EG3D + +EG3D adopts a StyleGAN2-based [18] generator $\mathcal{E}$ to efficiently synthesize the low-resolution feature field of a subject. The feature field is represented by the tri-plane representation which consists of three orthogonal 2D planes produced by reshaping the output feature map of $\mathcal{E}$ , given the latent code $z$ as input. For a point $\pmb{x} \in \mathbb{R}^3$ in the 3D space, its corresponding feature $\mathbf{f}$ can be obtained by projecting itself onto the three planes $\mathbf{P}_{xy}, \mathbf{P}_{yz}, \mathbf{P}_{zx}$ , and summing the retrieved features $\mathbf{f}_{xy}, \mathbf{f}_{yz}, \mathbf{f}_{zx}$ . A small MLP $\mathcal{M}$ then maps this intermediate feature to volume density $\sigma \in \mathbb{R}$ and color feature $\pmb{c} \in \mathbb{R}^{d_c}$ (the first three dimensions represent RGB color), forming the low-resolution feature field: + +$$ +\mathcal {M}: \mathbf {f} \in \mathbb {R} ^ {d ^ {\mathbf {f}}} \rightarrow (c, \sigma) \in \mathbb {R} ^ {d ^ {c}} \times \mathbb {R}. \tag {2} +$$ + +To generate high-resolution images, EG3D enforces volume rendering [14, 23] to render the above feature field to a low-resolution feature map $C$ , where each pixel value $C(\boldsymbol{r})$ corresponding to a viewing ray $\boldsymbol{r}$ can be obtained via + +$$ +C (\boldsymbol {r}) = \sum_ {i = 1} ^ {N} T _ {i} (1 - \exp (- \sigma_ {i} \delta_ {i})) \boldsymbol {c} _ {i}, T _ {i} = \exp (- \sum_ {j = 1} ^ {i - 1} \sigma_ {j} \delta_ {j}). \tag {3} +$$ + +Here, $i$ is the index of points along ray $r$ sorted from near to far, and $\delta$ is the distance between adjacent points. Then, the rendered feature map $C$ is sent to a 2D super-resolution module $S^{2D}$ consisting of several StyleGAN2-modulated convolutional layers to generate the final image $I^{2D}$ . + +Although EG3D can generate free-view images of high quality, it cannot well maintain their 3D consistency across different views. This is inevitable due to incorporating the black-box CNN-based 2D super-resolution mod + +![](images/73f98d857ddebfbcedb1e09800685ca779ed89a8f976f62879b902a03cc5138b.jpg) +Figure 3. Overview of our framework. 3D-to-2D imitation strategy is enforced to let the generator's 3D branch to mimic the results of its 2D branch, thus leading to image generation of high quality and strict 3D consistency. 3D-aware convolutions are also introduced to the tri-plane generator to enhance 3D representation learning, which further improves the image generation quality. + +ule, which breaks the physical rules of the volume rendering process. Despite that EG3D further proposes a dual-discrimination [3] strategy to force the high-resolution images to be consistent with their low-resolution counterparts, detail-level 3D inconsistency (i.e. texture flickering) still cannot be eliminated. During continuous camera variation, these artifacts can be easily captured by human eyes, differing the synthesized results from a real video sequence. To maintain the 3D consistency meanwhile keep the high-quality image generation to the maximum extent, we propose a 3D-to-2D imitation strategy described below. + +# 3.2. 3D-to-2D Imitation + +To keep the strict 3D consistency, a better way is to directly render the 3D representation instead of resorting to a 2D CNN for image synthesis. Noticing that the images generated by EG3D contain rich details, it is natural to use them as guidance for images synthesized by direct 3D rendering. If the directly-rendered images well mimic those fine details, their quality should get very close to that of EG3D. Meanwhile, since they are rendered from a continuous 3D representation, their 3D consistency across different views should be trivially maintained. This motivates us to design the 3D-to-2D imitation strategy, as depicted in Fig. 3. + +Specifically, we introduce a 3D super-resolution module $S^{3D}$ to generate residual tri-planes $\mathbf{P}^r$ from the coarse tri-planes $\mathbf{P}^c$ produced by the tri-plane generator $\mathcal{E}$ : + +$$ +\mathcal {S} ^ {3 D}: \mathbf {P} ^ {c} \in \mathbb {R} ^ {3 \times H ^ {c} \times W ^ {c} \times d ^ {\mathbf {f}}} \rightarrow \mathbf {P} ^ {r} \in \mathbb {R} ^ {3 \times H ^ {r} \times W ^ {r} \times d ^ {\mathbf {f}}}. \tag {4} +$$ + +The $S^{3D}$ adopts several StyleGAN2-modulated convolutional layers conditioned on a latent code $\pmb{w}$ mapped from the random code $\pmb{z}$ , similar to the 2D super-resolution module $S^{2D}$ in EG3D. The difference is that $S^{3D}$ conducts super-resolution on the triplane-based 3D representation instead of the rendered 2D feature map. In this way, we can + +generate a high-resolution 3D field for direct 3D rendering. Given the coarse and residual tri-planes (i.e. $\mathbf{P}^c$ and $\mathbf{P}^r$ ), we obtain a more detailed intermediate feature $\mathbf{f} = \mathbf{f}^c + \mathbf{f}^r$ for a 3D point $x$ , and further obtain the high-resolution feature field by sending the intermediate feature into the MLP-based decoder $\mathcal{M}$ following Eq. (2). The first three feature dimensions of the field derive the high-resolution NeRF for rendering 3D-consistent fine image $I^{3D}$ via Eq. (3). + +To ensure that $I^{3D}$ contains reasonable geometry structure with rich texture details, we let it to mimic the contents of $I^{2D}$ generated by the 2D branch $S^{2D}$ . For a pair of $I^{3D}$ and $I^{2D}$ synthesized with the same latent code $z$ and camera pose $\theta$ , we enforce imitation loss between them to guarantee their perceptual similarity: + +$$ +\mathcal {L} _ {\text {i m i t a t i o n}} = \operatorname {L P I P S} \left(I ^ {3 D}, \operatorname {s g} \left(I ^ {2 D}\right)\right), \tag {5} +$$ + +where $\mathrm{LPIPS}(\cdot ,\cdot)$ is the perceptual loss defined in [49], and sg denotes stopping gradient to avoid undesired influence of $I^{3D}$ on the 2D branch. This process is very similar to a standard multiview reconstruction process. During training, $I^{2D}$ sharing the same code $\mathbf{z}$ are generated under different camera views from a statistical aspect, forming the multiview supervision. The high-resolution NeRF from the 3D branch renders $I^{3D}$ under the same camera views to compare with the multiview data for 3D reconstruction. Considering that $I^{2D}$ are nearly 3D-consistent, they should help to learn a reasonable NeRF for 3D-consistent image rendering. + +Nevertheless, since $I^{2D}$ are not strictly 3D-consistent, faithfully reconstructing their image contents leads to blurry results where the texture details across different views are averaged out. Therefore, we further introduce the non-saturating GAN loss with R1 regularization [21] between $I^{3D}$ and real images $\hat{I}$ to maintain the high-frequency de + +tails: + +$$ +\begin{array}{l} \mathcal {L} _ {a d v} ^ {3 D} = \mathbb {E} _ {\boldsymbol {z} \sim p _ {z}, \boldsymbol {\theta} \sim p _ {\theta}} [ f (D ^ {3 D} (G ^ {3 D} (\boldsymbol {z}, \boldsymbol {\theta}))) ] \tag {6} \\ + \mathbb {E} _ {\hat {I} \sim p _ {r e a l}} [ f (- D ^ {3 D} (\hat {I})) + \lambda \| \nabla D ^ {3 D} (\hat {I})) \| ^ {2} ], \\ \end{array} +$$ + +where $f(u) = \log (1 + \exp (u))$ is the Softplus function, $G^{3D}$ including $\{\mathcal{E},\mathcal{M},\mathcal{S}^{3D}\}$ is the 3D rendering branch of the generator, and $D^{3D}$ is the corresponding discriminator. + +An advantage of the above imitation learning is that we can render small patches (i.e. $64 \times 64$ ) to compute Eq. (5) and Eq. (6), as shown in Fig. 3, with only minor influence to the final image quality. This largely reduces the memory cost during training and enables learning the 3D branch at high resolution (e.g. $512 \times 512$ ). By contrast, solely applying adversarial loss at patch-level often leads to large quality drops as shown in previous methods [35, 41] and Tab. 2. + +Finally, we apply image-level adversarial loss to the 2D branch following EG3D to ensure that $I^{2D}$ , as the supervision for the 3D branch, are of high quality: + +$$ +\begin{array}{l} \mathcal {L} _ {a d v} ^ {2 D} = \mathbb {E} _ {\boldsymbol {z} \sim p _ {z}, \boldsymbol {\theta} \sim p _ {\theta}} [ f (D ^ {2 D} (G ^ {2 D} (\boldsymbol {z}, \boldsymbol {\theta}))) ] \tag {7} \\ + \mathbb {E} _ {I \sim p _ {r e a l}} [ f (- D ^ {2 D} (\hat {I})) + \lambda \| \nabla D ^ {2 D} (\hat {I})) \| ^ {2} ], \\ \end{array} +$$ + +where $G^{2D}$ is the 2D branch generator consisting of $\{\mathcal{E},\mathcal{M},\mathcal{S}^{2D}\}$ , and $D^{2D}$ is the corresponding discriminator. The same dual discrimination is adopted as done in EG3D. + +Overall, the training objective is + +$$ +\mathcal {L} _ {\text {t o t a l}} = \mathcal {L} _ {\text {i m i t a t i o n}} + \mathcal {L} _ {\text {a d v}} ^ {3 D} + \mathcal {L} _ {\text {a d v}} ^ {2 D}. \tag {8} +$$ + +In practice, we first learn the 2D branch via $\mathcal{L}_{adv}^{2D}$ to obtain reasonable synthesized images $I^{2D}$ , then leverage $\mathcal{L}_{total}$ to simultaneously learn the 2D and 3D branches for high-quality and 3D-consistent image synthesis. + +# 3.3. 3D-Aware Tri-Plane Generator + +As depicted in Sec. 3.2, the tri-plane generator $\mathcal{E}$ is responsible for synthesizing the coarse tri-planes $\mathbf{P}^c$ shared by both the 2D and 3D branches, which is an important component that would affect the final image generation quality. However, in EG3D, $\mathcal{E}$ takes a StyleGAN2 architecture originally designed for 2D generative tasks. As shown in Fig. 4(a), the original tri-plane generator only contains the main stream and the output stream. The tri-planes are obtained from latent feature maps in the main stream via 2D convolutions (i.e. toRGB layers), and the latent feature maps are also produced by a serials of 2D synthesis blocks. Consequently, the latent feature maps are forced to learn 3D unaligned features of the three orthogonal planes and the latters also lack feature communications with each other. Inspired by a recent 3D diffusion model [44], we introduce 3D-aware convolutions into our tri-plane generator $\mathcal{E}$ to enhance feature communications between 3D-associated positions across different planes, for better tri-plane generation. + +![](images/70f80d0b4d1fceca7c9ccc518d9a3bf59cdca62cfbbad2b6ca2e50532f003be3.jpg) + +![](images/d96d7a3b654a58ecadfc4215cbb0d516c8587ee41a74d2cd7ce571f163e4bbb8.jpg) +Figure 4. (a) Structure of our 3D-aware tri-plane generator. (b) Operations of the 3D-aware block on $xy$ plane. + +Specifically, as illustrated in Fig. 4(a), we add an extra 3D-aware stream upon the original output stream after each toRGB layer at different resolutions. At each resolution level $k$ , the corresponding tri-planes $\mathbf{P}_k = [\mathbf{P}_{k,xy},\mathbf{P}_{k,yz},\mathbf{P}_{k,zx}]$ , are summed with the tri-planes produced by the original output stream, and further sent into a 3D-aware block to produce tri-plane features for the next level. The 3D-aware block conducts similar operations on each of the three planes. For brevity, we omit the subscript $k$ here and take $\mathbf{P}_{xy}$ as an example to illustrate the operation process. As shown in Fig. 4(b), to align $\mathbf{P}_{yz}$ and $\mathbf{P}_{zx}$ towards $\mathbf{P}_{xy}$ , we first perform global pooling along $z$ axis of the former two to obtain $z$ -squeezed feature vectors. These vectors are then repeated along the $z$ dimension to restore the original spatial size, denoted as $\mathbf{P}_{yr}$ and $\mathbf{P}_{rx}$ . In this manner, the obtained $\mathbf{P}_{yr}$ and $\mathbf{P}_{rx}$ are aligned with $\mathbf{P}_{xy}$ from a 3D perspective, i.e., a 2D position $uv$ on $\mathbf{P}_{xy}$ is responsible for features in region $uvz, z \in [z_{min}, z_{max}]$ in the 3D space, meanwhile the same $uv$ position on $\mathbf{P}_{yr}$ and $\mathbf{P}_{rx}$ also associate with the features in this 3D region. As a result, we can simply concatenate them along the channel dimension as $[\mathbf{P}_{xy},\mathbf{P}_{yr},\mathbf{P}_{rx}]$ , and perform modulated 2D convolution [18] on it. The 2D convolution aggregates the 3D-associated features to produce next-level $\mathbf{P}_{xy}$ , leading to better feature communications across the planes. $\mathbf{P}_{yz}$ and $\mathbf{P}_{zx}$ can be processed similarly. + +Note that in [44], the 3D-aware convolution is applied in all layers in a U-Net structure. However, in our scenario, leveraging 3D-aware convolution for all layers, especially the main stream, introduces unaffordable memory cost during training, as it would produce multiple auxiliary tensors + +![](images/9b710f27b2d8d9add99a85e353e11d3b1a178adb62dc7a5dff1aecaa3ea1be49.jpg) +EG3D + +![](images/330f4b7d46f9e0a6aa6ea432c37745412866796eebf6c97f4b9ca11b112a85e3.jpg) +Ours (3D branch) +Figure 5. Comparison between our method and EG3D on FFHQ at $512 \times 512$ resolution. Our method generates images with comparable quality to those of EG3D, while producing 3D geometries with finer details and multiview sequences with better 3D-consistency. + +![](images/6668d0c6ba3449c6a90f57a81e805ab39799784708cf66b7c208a41a3cf405a8.jpg) +GMPI + +![](images/144f4379c2bf7de7bfede9eb56f646ce71bc5594da7032ad790d416ac3f7e749.jpg) +EpiGRAF +Figure 6. Comparison between our method and other 3D rendering baselines on FFHQ at $512 \times 512$ resolution. Best viewed with zoom-in. + +![](images/f12d8146a65bc2ede645a372ed80dbeae1ab3ec63075360e29ed3b8f42fd1f73.jpg) +Ours (3D branch) + +and triples the channel dimension for each processed latent feature map, as shown in Fig. 4(b). Comparing to the latent feature maps in the main stream, the tri-planes after each output layer contains much fewer channels thus more memory-friendly to adopt the 3D-aware convolution. Empirically, our proposed 3D-aware stream helps to learn more reasonable tri-planes and improves the final image generation quality, with only a minor increase in the total memory consumption (see Sec. 4.3). + +# 4. Experiments + +Implementation details. We train our method on two real-world datasets: FFHQ [17] and AFHQ-v2 Cats [5], which consists of 70K human face images of $1024^2$ resolution and 5.5K cat face images of $512^2$ resolution, respectively. We follow the data pre-processing of EG3D [3] to crop and resize the images to $256^2$ or $512^2$ resolution. Experiments are conducted on 8 NVIDIA Tesla A100 GPUs with 40GB memory, following the training configuration of EG3D. For FFHQ, the training process takes around 8 days, where learning the 2D branch takes 5 days and jointly training the whole framework takes additional 3 days. For AFHQ-v2, we finetune the 2D branch initially trained on FFHQ for 1 day, then jointly train the whole framework for extra 3 days. Adaptive data augmentation [15] is applied to AFHQ-v2 to facilitate training with limited data. See the suppl. material for more details. + +# 4.1. Visual Results + +Figure 2 shows the multiview images generated by our 3D branch generator. It can produce high-quality images with fine details at a resolution of $512^2$ . Moreover, the images are of strict 3D consistency across different views via directly rendering the generated high-resolution NeRF. More results are in Fig. 5, 6, and the suppl. material. + +# 4.2. Comparison with Prior Arts + +Baselines. We compare our method with existing 3D-aware GANs, including methods leveraging 2D superresolution: StyleSDF [27], VolumeGAN [47], StyleN-erF [9], and EG3D [3]; and methods with direct 3D rendering: GRAM [6], GRAM-HD [45], GMPI [52], EpiGRAF [41], and VoxGRAF [36]. + +Qualitative comparison. Figure 5 shows the visual comparison between our method and EG3D. Our generated images via direct rendering have comparable quality with those generated by EG3D via 2D super-resolution. We further visualize the 3D geometry and the spatiotemporal texture images [45] of the two methods. The geometry is extracted via Marching Cubes [20] on the density field at $512^{3}$ resolution. The spatiotemporal textures are obtained by stacking the pixels of a fixed line segment under continuous camera change, very similar to the Epipolar Line Images [1], where smoothly tilted strips indicate better 3D + +
MethodFFHQ256FFHQ512CATS256CATS512
FID ↓PSNR\( _{mv} \) ↑SSIM\( _{mv} \) ↑FID ↓PSNR\( _{mv} \) ↑SSIM\( _{mv} \) ↑FID ↓FID ↓
w/2D SRStyleSDF [27]11.5--11.2---7.91
VolumeGAN [47]9.1033.60.926-----
StyleNeRF [9]8.0031.90.9157.8030.90.843--
EG3D [3]4.8034.00.9284.7032.40.8613.882.77
Ours (2D branch)3.9135.70.9384.1433.30.8913.412.72
w/o 2D SRGRAM [6]13.838.00.966---13.4-
GRAM-HD [45]10.436.50.955----7.67
GMPI [52]11.439.80.9778.2939.00.961-7.79
EpiGRAF [41]9.71--9.9237.30.9496.93-
VoxGRAF [36]9.6037.20.960---9.60-
Ours (3D branch)5.1439.30.9745.3737.80.9554.144.29
+ +Table 1. Comparison on image generation quality and 3D consistency among different 3D-aware GANs. + +consistency. As shown, our geometries contain finer details in that we directly learn the NeRF of a subject at high resolution. Our spatiotemporal textures are also more reasonable with fewer twisted patterns, thanks to the direct 3D rendering for image synthesis instead of using a black-box 2D super-resolution module. + +Figure 6 compares our method with other 3D baselines on FFHQ at $512^{2}$ resolution. Visually inspected, our 3D branch produces images of higher fidelity compared to existing methods leveraging direct 3D rendering. More analysis and video results can be found in the suppl. material. + +Quantitative comparison. Table 1 and Fig. 1 show the quantitative results of different methods in terms of image generation quality and 3D consistency. For image generation quality, We calculate the Frechet Inception Distance (FID) [12] between 50K generated images and all available real images in the training set. For 3D consistency, we follow GRAM-HD [45] to generate multiview images of 50 random subjects and train the multiview reconstruction method NeuS [43] on each of them. We report the average PSNR and SSIM scores between our generated multiview images and the re-rendered images of NeuS (denoted as $\mathrm{PSNR}_{mv}$ and $\mathrm{SSIM}_{mv}$ ). Theoretically, better 3D consistency facilitates the 3D reconstruction process of NeuS, thus leading to higher PSNR and SSIM. + +As shown, our 2D branch generator demonstrates better results compared to EG3D in all metrics across different datasets, thanks to our 3D-aware stream in the tri-plane generator. Moreover, with the 3D-to-2D imitation strategy, our 3D branch generator largely improves the image generation quality among methods using direct 3D rendering, while maintaining competitive 3D consistency. Its image quality even surpasses most of the methods with 2D superresolution and comes very close to that of EG3D. + +# 4.3. Ablation Study + +We conduct ablation studies to validate the efficacy of our proposed 3D-to-2D imitation and the 3D-aware tri + +
Label\( \mathcal{L}_{\text{limitation}} \)\( \mathcal{S}^{3D} \)\( \mathcal{L}_{\text{adv}}^{3D} \)FID (3D branch)
(A)30.6
(B)✓29.9
(C)✓✓9.29
(D)✓✓22.8
(E)✓✓✓5.14
+ +Table 2. Ablation study on 3D-to-2D imitation strategy. + +![](images/833fae670dccd3ebb76eefcbee3025926eb4faddbdc58f5eddd41c0b1f80d2ac.jpg) +(A) + +![](images/22218623e84f17997f010abacc636b037bbe76e13a23dfac5d225c7a5bb07638.jpg) +(C) + +![](images/09da423f0ddfe8a015fd99b3a0ec024205f7d1affa1101add44a0ad2d48cdacd.jpg) +(D) +Figure 7. Generated images under different learning strategies. The labels are consistent with Tab. 2. + +![](images/b4abef14d9aba9aff194d61950270337fb308c6faf33754ceb152a52bd24a6f0.jpg) +(E) + +plane generator. For efficiency, all experiments are conducted on FFHQ dataset at $256^{2}$ resolution. + +3D-to-2D imitation strategy. As shown in Tab. 2 and Fig. 7, We start from a generator without using the 3D-to-2D imitation and the 3D super-resolution module $S^{3D}$ (setting A), by directly rendering the coarse tri-planes $\mathbf{P}^c$ for image synthesis. The rendered images in this way are blurry and lack fine details, leading to a high FID score of 30.6. Naively introducing the imitation loss (setting B) to improve the rendered images of $\mathbf{P}^c$ has minor influence, as the capacity of the coarse tri-planes are limited. Further incorporating the 3D super-resolution module (setting C) effectively releases the potential of the imitation loss and largely improves the image generation quality in terms of FID. However, the rendered images still lack rich details limited by the 3D-inconsistent 2D branch supervisions. Then, if the imitation loss is replaced with the adversarial loss (setting D), the image quality decreases significantly. This is due to that we only render small image patches to compute the corresponding losses for memory consideration. Under this circumstance, the adversarial loss is less + +
MethodFID (2D)FID (3D)#ParamMem.
w/o 3D-aware4.806.7129.0M2.3G
3D-aware latentOOMOOM111.7M11.6G
3D-aware tri-plane4.14-32.6M2.4G
3D-aware stream (Ours)3.915.1432.6M2.4G
+ +Table 3. Ablation study on designs of 3D-aware tri-plane generator. The FID scores are from 2D or 3D branch; #Param only considers the tri-plane generator $\mathcal{E}$ and Mem. indicates the GPU memory cost for generating the coarse tri-planes. + +![](images/96d7879c2b5af697e46cfa36f3d6f9753a24cc864d5707dbfb524698677d7a7e.jpg) +Figure 8. Generated tri-planes with or w/o 3D-aware convolutions. + +stable compared to the imitation loss which is a perceptual-level reconstruction loss. This reveals the advantage of our imitation strategy, which could be extended to higher resolution via patch-wise optimization while maintaining a good image generation quality. Finally, leveraging all the three components (setting E) yields the best result, where the imitation loss keeps the overall structure reasonable and the adversarial loss helps with fine details learning. + +3D-aware tri-plane generator. Table 3 shows the ablation study on the 3D-aware tri-plane generator. We compare our design with two alternatives and one without 3D-aware convolutions originally adopted by EG3D. We report the parameter size of the tri-plane generators, the inference memory cost to generate the coarse tri-planes, as well as the final image generation quality in terms of FID. In the first alternative, we remove our 3D-aware stream, and leverage 3D-aware convolutions for the latent feature maps in the main stream, namely 3D-aware latent. Since the main stream feature maps have relatively larger feature channels, and the 3D-aware convolution requires to concatenate two additional tensors with the same size as the input tensor, this + +design increases the parameter size and memory consumption significantly, and raises the out-of-memory issue during training. In the second alternative, namely 3D-aware tri-plane, we directly apply 3D-aware convolutions in the output stream, by inserting them after the upsampling operations at each resolution, instead of using the additional 3D-aware stream. This strategy leads to an improvement of the image generation quality of the 2D branch, and largely reduces the parameter size and memory cost compare to the first design. Finally, our 3D-aware stream design further improves the image generation quality without introducing extra parameters and memory costs. Therefore, we adopt it as our final 3D-aware tri-plane generator for 3D-to-2D imitation. It effectively lowers the FID score of both the 2D and 3D branches compared to the original structure without 3D-aware convolutions, with only a minor increase of the parameter size and memory cost. + +Figure 8 further shows the synthesized tri-planes, where we visualize the L2 norm of each spatial location on the three orthogonal planes. Our method leveraging the 3D-aware stream produces more informative tri-planes. The generated planes of the side-views better depict the characters of different instances (e.g., see the difference of the profiles on the $yz$ planes). Our frontal planes (i.e. $xy$ planes) also demonstrate more clear head silhouettes compared to those without using the 3D-aware convolutions. + +# 5. Conclusions + +We presented a novel learning strategy for 3D-aware GANs to achieve image synthesis of high quality and strict 3D consistency. The core idea is to enforce the images synthesized by the generator's 3D rendering branch to mimic those generated by its 2D super-resolution branch. We also introduced 3D-aware convolutions to the generator to further improve the image generation quality. With the above strategies, our method largely improves the image quality among methods using direct 3D rendering, which we believe enables a new way for more realistic 3D generation. + +Limitation and future works. Our method has several limitations. The image generation quality of its 3D branch still lags behind that of the 2D branch. Certain generated 3D structures such as hairs and cat whiskers are stuck to the geometry surfaces instead of correctly floating in the volumetric space. The 3D-to-2D imitation strategy also introduces extra training time and memory costs compared to only learning the 2D branch. We expect more effective learning strategies and more advanced 3D representations to alleviate these problems. + +Ethics consideration. The goal of this paper is to generate images of virtual subjects. It is not intended for creating misleading or deceptive contents of real people and we do not condone any such harmful behavior. + +# References + +[1] Robert C Bolles, H Harlyn Baker, and David H Marimont. Epipolar-plane image analysis: An approach to determining structure from motion. International journal of computer vision, 1(1):7-55, 1987. 6 +[2] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale GAN training for high fidelity natural image synthesis. In Proceedings of the International Conference on Learning Representations, 2019. 3 +[3] Eric R Chan, Connor Z Lin, Matthew A Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas Guibas, Jonathan Tremblay, Sameh Khamis, et al. Efficient geometry-aware 3D generative adversarial networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1, 2, 3, 4, 6, 7 +[4] Eric R Chan, Marco Monteiro, Petr Kellnhofer, Jiajun Wu, and Gordon Wetzstein. pi-GAN: Periodic implicit generative adversarial networks for 3D-aware image synthesis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. 1, 2, 3 +[5] Yunjey Choi, Youngjung Uh, Jaejun Yoo, and Jung-Woo Ha. StarGAN v2: Diverse image synthesis for multiple domains. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, 2020. 2, 6 +[6] Yu Deng, Jiaolong Yang, Jianfeng Xiang, and Xin Tong. GRAM: Generative radiance manifolds for 3D-aware image generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1, 2, 3, 6, 7 +[7] Terrance DeVries, Miguel Angel Bautista, Nitish Srivastava, Graham W Taylor, and Joshua M Susskind. Unconstrained scene generation with locally conditioned radiance fields. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2021. 3 +[8] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In Proceedings of the Advances in Neural Information Processing Systems, 2014. 1, 3 +[9] Jiatao Gu, Lingjie Liu, Peng Wang, and Christian Theobalt. StyleNeRF: A style-based 3D aware generator for high-resolution image synthesis. In Proceedings of the International Conference on Learning Representations, 2022. 1, 2, 3, 6, 7 +[10] Erik Härkönen, Aaron Hertzmann, Jaakko Lehtinen, and Sylvain Paris. GANSpace: Discovering interpretable GAN controls. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 3 +[11] Philipp Henzler, Niloy J Mitra, and Tobias Ritschel. Escaping plato's cave: 3D shape from adversarial rendering. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2019. 2, 3 +[12] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. GANs trained by a two time-scale update rule converge to a local nash equilibrium. In Proceedings of the Advances in Neural Information Processing Systems, 2017. 2, 7 + +[13] Ali Jahanian, Lucy Chai, and Phillip Isola. On the "steerability" of generative adversarial networks. In Proceedings of the International Conference on Learning Representations, 2020. 3 +[14] James T Kajiya and Brian P Von Herzen. Ray tracing volume densities. ACM SIGGRAPH, 18(3):165-174, 1984. 1, 3 +[15] Tero Karras, Miika Aittala, Janne Hellsten, Samuli Laine, Jaakko Lehtinen, and Timo Aila. Training generative adversarial networks with limited data. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 6 +[16] Tero Karras, Miika Aittala, Samuli Laine, Erik Härkönen, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Alias-free generative adversarial networks. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 1 +[17] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4401-4410, 2019. 2, 3, 6 +[18] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of styleGAN. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. 1, 3, 5 +[19] Chen-Hsuan Lin, Jun Gao, Luming Tang, Towaki Takikawa, Xiaohui Zeng, Xun Huang, Karsten Kreis, Sanja Fidler, Ming-Yu Liu, and Tsung-Yi Lin. Magic3D: High-resolution text-to-3D content creation. arXiv:2211.10440, 2022. 3 +[20] William E Lorensen and Harvey E Cline. Marching cubes: A high resolution 3D surface construction algorithm. ACM SIGGRAPH, 21(4):163-169, 1987. 6 +[21] Lars Mescheder, Andreas Geiger, and Sebastian Nowozin. Which training methods for GANs do actually converge? In Proceedings of the International Conference on Machine Learning, 2018. 4 +[22] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3D reconstruction in function space. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. 3 +[23] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. In Proceedings of the European Conference on Computer Vision, 2020. 1, 3 +[24] Thu Nguyen-Phuoc, Chuan Li, Lucas Theis, Christian Richardt, and Yong-Liang Yang. Hologan: Unsupervised learning of 3D representations from natural images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7588-7597, 2019. 2, 3 +[25] Michael Niemeyer and Andreas Geiger. Giraffe: Representing scenes as compositional generative neural feature fields. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11453-11464, 2021. 1, 2, 3 +[26] Michael Oechsle, Songyou Peng, and Andreas Geiger. Unisurf: Unifying neural implicit surfaces and radiance + +fields for multi-view reconstruction. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2021. 3 +[27] Roy Or-El, Xuan Luo, Mengyi Shan, Eli Shechtman, Jeong Joon Park, and Ira Kemelmacher-Shlizerman. StyleSDF: High-resolution 3D-consistent image and geometry generation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2022. 1, 3, 6, 7 +[28] Xingang Pan, Bo Dai, Ziwei Liu, Chen Change Loy, and Ping Luo. Do 2D GANs know 3D shape? unsupervised 3D shape reconstruction from 2d image gans. In Proceedings of the International Conference on Learning Representations, 2021. 2, 3 +[29] Xingang Pan, Ayush Tewari, Lingjie Liu, and Christian Theobalt. Gan2x: Non-lambertian inverse rendering of image gans. In Proceedings of the International Conference on 3D Vision, 2022. 3 +[30] Xingang Pan, Xudong Xu, Chen Change Loy, Christian Theobalt, and Bo Dai. A shading-guided generative implicit model for shape-accurate 3D-aware image synthesis. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 3 +[31] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. DeepSDF: Learning continuous signed distance functions for shape representation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. 3 +[32] Ben Poole, Ajay Jain, Jonathan T Barron, and Ben Mildenhall. Dreamfusion: Text-to-3D using 2D diffusion. arXiv:2209.14988, 2022. 2, 3 +[33] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 3 +[34] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Raphael Gontijo-Lopes, Burcu Karagol Ayan, Tim Salimans, et al. Photorealistic text-to-image diffusion models with deep language understanding. In Proceedings of the Advances in Neural Information Processing Systems, 2022. 3 +[35] Katja Schwarz, Yiyi Liao, Michael Niemeyer, and Andreas Geiger. GRAF: Generative radiance fields for 3D-aware image synthesis. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 1, 2, 3, 5 +[36] Katja Schwarz, Axel Sauer, Michael Niemeyer, Yiyi Liao, and Andreas Geiger. VoxGRAF: Fast 3D-aware image synthesis with sparse voxel grids. In Proceedings of the Advances in Neural Information Processing Systems, 2022. 1, 3, 6, 7 +[37] Yujun Shen, Jinjin Gu, Xiaou Tang, and Bolei Zhou. Interpreting the latent space of GANs for semantic face editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. 3 +[38] Yichun Shi, Divyansh Aggarwal, and Anil K Jain. Lifting 2D StyleGAN for 3D-aware face generation. In Proceedings of + +the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. 3 +[39] Vincent Sitzmann, Julien Martel, Alexander Bergman, David Lindell, and Gordon Wetzstein. Implicit neural representations with periodic activation functions. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 3 +[40] Vincent Sitzmann, Michael Zollhöfer, and Gordon Wetzstein. Scene representation networks: continuous 3D-structure-aware neural scene representations. In Proceedings of the Advances in Neural Information Processing Systems, 2019. 3 +[41] Ivan Skorokhodov, Sergey Tulyakov, Yiqun Wang, and Peter Wonka. EpiGRAF: Rethinking training of 3D GANs. In Proceedings of the Advances in Neural Information Processing Systems, 2022. 1, 2, 3, 5, 6, 7 +[42] Attila Szabó, Givi Meishvili, and Paolo Favaro. Unsupervised generative 3D shape learning from natural images. arXiv:1910.00287, 2019. 3 +[43] Peng Wang, Lingjie Liu, Yuan Liu, Christian Theobalt, Taku Komura, and Wenping Wang. NeuS: Learning neural implicit surfaces by volume rendering for multi-view reconstruction. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 1, 3, 7 +[44] Tengfei Wang, Bo Zhang, Ting Zhang, Shuyang Gu, Jianmin Bao, Tadas Baltrusaitis, Jingjing Shen, Dong Chen, Fang Wen, Qifeng Chen, et al. Rodin: A generative model for sculpting 3D digital avatars using diffusion. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, 2023. 2, 3, 5 +[45] Jianfeng Xiang, Jiaolong Yang, Yu Deng, and Xin Tong. GRAM-HD: 3D-consistent image generation at high resolution with generative radiance manifolds. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2023. 1, 3, 6, 7 +[46] Xudong Xu, Xingang Pan, Dahua Lin, and Bo Dai. Generative occupancy fields for 3D surface-aware image synthesis. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 3 +[47] Yinghao Xu, Sida Peng, Ceyuan Yang, Yujun Shen, and Bolei Zhou. 3D-aware image synthesis via learning structural and textural representations. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18430-18439, 2022. 3, 6, 7 +[48] Yang Xue, Yuheng Li, Krishna Kumar Singh, and Yong Jae Lee. Giraffe HD: A high-resolution 3D-aware generative model. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18440-18449, 2022. 1, 3 +[49] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2018. 2, 4 +[50] Xuanmeng Zhang, Zhedong Zheng, Daiheng Gao, Bang Zhang, Pan Pan, and Yi Yang. Multi-view consistent generative adversarial networks for 3D-aware image synthesis. + +In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2 +[51] Yuxuan Zhang, Wenzheng Chen, Huan Ling, Jun Gao, Yi-nan Zhang, Antonio Torralba, and Sanja Fidler. Image gans meet differentiable rendering for inverse graphics and interpretable 3D neural rendering. In Proceedings of the International Conference on Learning Representations, 2021. 2, 3 +[52] Xiaoming Zhao, Fangchang Ma, David Guera, Zhile Ren, Alexander G Schwing, and Alex Colburn. Generative multiplane images: Making a 2D GAN 3D-aware. In Proceedings of the European Conference on Computer Vision, 2022. 1, 2, 3, 6, 7 +[53] Peng Zhou, Lingxi Xie, Bingbing Ni, and Qi Tian. Cips-3d: A 3D-aware generator of gans based on conditionally-independent pixel synthesis. arXiv:2110.09788, 2021. 3 \ No newline at end of file diff --git a/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/images.zip b/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..466bc94c3d94a2bd5673373fd7e488c36a7f139f --- /dev/null +++ b/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:ba04eebdba01e9724bef5527e60ca4915a7edf004418497453a3d52b39214e9c +size 571302 diff --git a/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/layout.json b/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..a3816a58b514b4cd7a6e2188bca7c246bfbc90ea --- /dev/null +++ b/2023/Mimic3D_ Thriving 3D-Aware GANs via 3D-to-2D Imitation/layout.json @@ -0,0 +1,9021 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 111, + 103, + 483, + 120 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 103, + 483, + 120 + ], + "spans": [ + { + "bbox": [ + 111, + 103, + 483, + 120 + ], + "type": "text", + "content": "Mimic3D: Thriving 3D-Aware GANs via 3D-to-2D Imitation" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 186, + 143, + 407, + 172 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 186, + 143, + 407, + 172 + ], + "spans": [ + { + "bbox": [ + 186, + 143, + 407, + 172 + ], + "type": "text", + "content": "Xingyu Chen* Yu Deng* Baoyuan Wang Xiaobing.AI" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 199, + 192, + 211 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 199, + 192, + 211 + ], + "spans": [ + { + "bbox": [ + 143, + 199, + 192, + 211 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 224, + 289, + 499 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 224, + 289, + 499 + ], + "spans": [ + { + "bbox": [ + 46, + 224, + 289, + 499 + ], + "type": "text", + "content": "Generating images with both photorealism and multiview 3D consistency is crucial for 3D-aware GANs, yet existing methods struggle to achieve them simultaneously. Improving the photorealism via CNN-based 2D super-resolution can break the strict 3D consistency, while keeping the 3D consistency by learning high-resolution 3D representations for direct rendering often compromises image quality. In this paper, we propose a novel learning strategy, namely 3D-to-2D imitation, which enables a 3D-aware GAN to generate high-quality images while maintaining their strict 3D consistency, by letting the images synthesized by the generator's 3D rendering branch mimic those generated by its 2D super-resolution branch. We also introduce 3D-aware convolutions into the generator for better 3D representation learning, which further improves the image generation quality. With the above strategies, our method reaches FID scores of 5.4 and 4.3 on FFHQ and AFHQ-v2 Cats, respectively, at " + }, + { + "bbox": [ + 46, + 224, + 289, + 499 + ], + "type": "inline_equation", + "content": "512 \\times 512" + }, + { + "bbox": [ + 46, + 224, + 289, + 499 + ], + "type": "text", + "content": " resolution, largely outperforming existing 3D-aware GANs using direct 3D rendering and coming very close to the previous state-of-the-art method that leverages 2D super-resolution. Project website: https://seancheny.github.io/Mimic3DWeb." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 521, + 127, + 533 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 521, + 127, + 533 + ], + "spans": [ + { + "bbox": [ + 47, + 521, + 127, + 533 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 540, + 287, + 696 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 540, + 287, + 696 + ], + "spans": [ + { + "bbox": [ + 46, + 540, + 287, + 696 + ], + "type": "text", + "content": "3D-aware GANs [35, 9, 6, 3] have experienced rapid development in recent years and shown great potential for large-scale realistic 3D content creation. The core of 3D-aware GANs is to incorporate 3D representation learning and differentiable rendering into image-level adversarial learning [8]. In this way, the generated 3D representations are forced to mimic real image distribution from arbitrary viewing angles, resulting in their faithful reconstruction of the underlying 3D structures of the subjects for free-view image synthesis. Among different 3D representations, neural radiance field (NeRF) [23] has been proven to be effective in the 3D-aware GAN scenario [35, 4], which guarantees strong 3D consistency when synthesizing multiview" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 309, + 198, + 545, + 342 + ], + "blocks": [ + { + "bbox": [ + 309, + 198, + 545, + 342 + ], + "lines": [ + { + "bbox": [ + 309, + 198, + 545, + 342 + ], + "spans": [ + { + "bbox": [ + 309, + 198, + 545, + 342 + ], + "type": "image", + "image_path": "5d543cc189a12fdc2d92e21927db9373e1468b78ca41ba399cbc799c49479c03.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 343, + 546, + 443 + ], + "lines": [ + { + "bbox": [ + 304, + 343, + 546, + 443 + ], + "spans": [ + { + "bbox": [ + 304, + 343, + 546, + 443 + ], + "type": "text", + "content": "Figure 1. Comparison between different 3D-aware GANs on image generation quality and multiview 3D consistency. The image generation quality is evaluated via FID between generated and real images. The 3D consistency is measured by conducting 3D reconstruction [43] on generated multiview images and calculating PSNR between them and the re-rendered reconstruction results. Our method inherits the high image quality of approaches leveraging 2D super-resolution meanwhile maintains strict 3D consistency by taking the advantage of direct 3D rendering." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 469, + 447, + 481 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 469, + 447, + 481 + ], + "spans": [ + { + "bbox": [ + 306, + 469, + 447, + 481 + ], + "type": "text", + "content": "images via volume rendering [14]." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 483, + 546, + 579 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 483, + 546, + 579 + ], + "spans": [ + { + "bbox": [ + 304, + 483, + 546, + 579 + ], + "type": "text", + "content": "However, NeRF's volumetric representation also brings high computation costs to GAN training. This hinders the generative models from synthesizing high-resolution images with fine details. Several attempts have been made to facilitate NeRF-based GAN training at high resolution, via sparse representations [36, 6, 45, 52] or patch-wise adversarial learning [41], yet the performance is still unsatisfactory and lags far behind state-of-the-art 2D GANs [18, 16]." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 547, + 715 + ], + "type": "text", + "content": "Along another line, instead of using direct NeRF rendering, plenty of works [25, 9, 27, 3, 48] introduce 2D super-resolution module to deal with 3D-aware GAN training at high resolution. A typical procedure is to first render a NeRF-like feature field into low-resolution feature maps, then apply a 2D CNN to generate high-resolution images from them. The representative work among this line, namely EG3D [3], utilizes tri-plane representation to effectively model the low-resolution feature field and leverages StyleGAN2-like [18] super-resolution block to achieve image synthesis at high-quality. It sets a record for image" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 702, + 231, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 702, + 231, + 712 + ], + "spans": [ + { + "bbox": [ + 58, + 702, + 231, + 712 + ], + "type": "text", + "content": "*These authors have contributed equally to this work." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2338" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 71, + 545, + 183 + ], + "blocks": [ + { + "bbox": [ + 50, + 71, + 545, + 183 + ], + "lines": [ + { + "bbox": [ + 50, + 71, + 545, + 183 + ], + "spans": [ + { + "bbox": [ + 50, + 71, + 545, + 183 + ], + "type": "image", + "image_path": "37405ceb46c1fb694d9a2fee9073fbba0c0f776941bdb01c291334cbc2b6acc9.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 60, + 186, + 531, + 198 + ], + "lines": [ + { + "bbox": [ + 60, + 186, + 531, + 198 + ], + "spans": [ + { + "bbox": [ + 60, + 186, + 531, + 198 + ], + "type": "text", + "content": "Figure 2. Our method enables high-quality image generation at " + }, + { + "bbox": [ + 60, + 186, + 531, + 198 + ], + "type": "inline_equation", + "content": "512 \\times 512" + }, + { + "bbox": [ + 60, + 186, + 531, + 198 + ], + "type": "text", + "content": " resolution without using a 2D super-resolution module." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 220, + 287, + 268 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 220, + 287, + 268 + ], + "spans": [ + { + "bbox": [ + 46, + 220, + 287, + 268 + ], + "type": "text", + "content": "quality among 3D-aware GANs and gets very close to that of state-of-the-art 2D GANs. However, a fatal drawback of this line of works is a sacrifice of strict 3D consistency, due to leveraging a black-box 2D CNN for image synthesis." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 270, + 287, + 353 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 270, + 287, + 353 + ], + "spans": [ + { + "bbox": [ + 46, + 270, + 287, + 353 + ], + "type": "text", + "content": "A question naturally arises — Is there any way to combine the above two lines to achieve strict 3D consistency and high-quality image generation simultaneously? The answer, as we will show in this paper, is arguably yes. The key intuition is to let the images synthesized by direct NeRF rendering to mimic those generated by a 2D superresolution module, which we name 3D-to-2D imitation." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 354, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 354, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 354, + 288, + 713 + ], + "type": "text", + "content": "Specifically, we start from an EG3D backbone that adopts 2D super-resolution to generate high-resolution images from a low-resolution feature field. Based on this architecture, we add another 3D super-resolution module to generate high-resolution NeRF from the low-resolution feature field and force the images rendered by the former to imitate those generated by the 2D super-resolution branch. This process can be seen as a multiview reconstruction process — images sharing the same latent code from different views produced by the 2D branch are pseudo multiview data, and the high-resolution NeRF branch represents the 3D scene to be reconstructed. Previous methods [28, 51, 32] have shown that this procedure can obtain reasonable 3D reconstruction, even if the multiview data are not strictly 3D consistent. We believe this is partially due to the inductive bias (e.g., continuity and sparsity) of the underlying 3D representation. With the above process, the high-resolution NeRF learns to depict fine details of the 2D-branch images, thus enabling high-quality image rendering. The 3D consistency across different views can also be preserved thanks to the intrinsic property of NeRF. Note that if the rendered images try to faithfully reconstruct every detail of the 2D-branch images across different views, it is likely to obtain blurry results due to detail-level 3D inconsistency of the latter. To avoid this problem, we only let the images produced by the two branches be perceptually similar (i.e. by LPIPS loss [49]), and further enforce adversarial loss between the rendered images from the high-resolution NeRF and real images to maintain high-frequency details. In addition, we only render small image patches to conduct the imitative" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 306, + 220, + 441, + 232 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 220, + 441, + 232 + ], + "spans": [ + { + "bbox": [ + 306, + 220, + 441, + 232 + ], + "type": "text", + "content": "learning to reduce memory costs." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 233, + 545, + 437 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 233, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 304, + 233, + 545, + 437 + ], + "type": "text", + "content": "Apart from the above learning strategy, we introduce 3D-aware convolutions to the EG3D backbone to improve tri-plane learning, motivated by a recent 3D diffusion model [44]. The original EG3D generates tri-plane features to model the low-resolution feature field via a StyleGAN2-like generator. The generator is forced to learn 2D-unaligned features on the three orthogonal planes via 2D convolutions, which is inefficient. The 3D-aware convolution considers associated features in 3D space when performing 2D convolution, which improves feature communications and helps to produce more reasonable tri-planes. Nevertheless, directly applying 3D-aware convolution in all layers in the generator is unaffordable. As a result, we only apply them after the output layers at each resolution in the tri-plane generator. This helps us to further improve the image generation quality with only a minor increase in the total memory consumption." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 438, + 546, + 618 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 438, + 546, + 618 + ], + "spans": [ + { + "bbox": [ + 304, + 438, + 546, + 618 + ], + "type": "text", + "content": "With the above strategies, our generator is able to synthesize 3D-consistent images of virtual subjects with high image quality (Fig. 2). It reaches FID scores [12] of 5.4 and 4.3 on FFHQ [17] and AFHQ-v2 Cats [5], respectively, at " + }, + { + "bbox": [ + 304, + 438, + 546, + 618 + ], + "type": "inline_equation", + "content": "512 \\times 512" + }, + { + "bbox": [ + 304, + 438, + 546, + 618 + ], + "type": "text", + "content": " resolution, largely outperforming previous 3D-aware GANs with direct 3D rendering and even surpassing many leveraging 2D super-resolution (Fig. 1). A by-product of our method is a more powerful 2D-branch generator, which reaches an FID of 4.1 on FFHQ, exceeding previous state-of-the-art EG3D. Though our method presented in this paper is mostly based on EG3D backbone, its 3D-to-2D imitation strategy can be extended to learning other 3D-aware GANs as well. We believe this would largely close the quality gap between 3D-aware GANs and traditional 2D GANs, and pave a new way for realistic 3D generation." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 632, + 398, + 644 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 632, + 398, + 644 + ], + "spans": [ + { + "bbox": [ + 306, + 632, + 398, + 644 + ], + "type": "text", + "content": "2. Related Works" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 653, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 715 + ], + "type": "text", + "content": "3D-aware GAN. 3D-aware GANs [11, 24, 35, 4, 25, 9, 50, 6, 3, 41, 52] aim to generate multiview images of an object category, given only in-the-wild 2D images as training data. The key is to represent the generated scenes via a 3D representation and leverage corresponding rendering" + } + ] + } + ], + "index": 9 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2339" + } + ] + } + ], + "index": 10 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 289, + 396 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 289, + 396 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 289, + 396 + ], + "type": "text", + "content": "techniques to synthesize images at different viewpoints for image-level adversarial learning [8]. Initially, explicit representations such as voxels [24, 11] and meshes [42] are used to describe scenes. With the development of neural implicit fields [31, 22, 40, 39, 23, 43, 26], implicit scene representations, especially NeRF [23], gradually overtake explicit ones in 3D-aware GANs [4, 27, 3]. Nevertheless, one great hurdle of NeRF-based GANs is the high computation cost, which restricts earlier works [35, 4, 7, 46, 30] from synthesizing high-quality images. Consequently, a large number of follow-up works [25, 9, 53, 48, 27, 3, 47] avoid rendering NeRF at high resolution by conducting 2D super-resolution from a low-resolution image or feature map rendered by NeRF-like fields. This is only a stopgap as the black-box 2D super-resolution module sacrifices the important 3D consistency brought by NeRF. To keep the strict 3D consistency, several works [6, 45, 36, 41, 52] turn to more sparse 3D representations such as sparse voxel [36], radiance manifolds [6], and multi-plane images [52] to allow direct rendering at high resolution. Carefully designed training strategies such as two-stage training [45] or patch-wise optimization [41] are also introduced to facilitate the learning process. However, their image generation quality still lags behind those with 2D super-resolution. Our method combines the advantages of both lines of works to achieve high-quality image generation and strict 3D consistency at once, by leveraging the proposed 3D-to-2D imitation." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 405, + 289, + 657 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 405, + 289, + 657 + ], + "spans": [ + { + "bbox": [ + 47, + 405, + 289, + 657 + ], + "type": "text", + "content": "3D generation by 3D-to-2D imitation. Recent studies [13, 37, 10] reveal that 2D generative models [2, 17] have the ability to generate pseudo multiview images of a subject. Based on this observation, several methods [28, 51, 38, 29] propose to distill the knowledge from a pretrained 2D generative model for 3D generation by performing 3D reconstruction on the generated \"multiview\" images. A standard procedure is to render the 3D representation of an object from multiple views, and compare them with the closest samples falling in the latent space of the pre-trained 2D generator for iterative optimization. The 2D generator ensures that the rendered results are photorealistic from different views, meanwhile the intrinsic property of the 3D representation guarantees reasonable 3D structure, thus leading to high-quality 3D generation. Some recent methods [32, 19] also combine this idea with text-to-image diffusion models [33, 34] to achieve text-driven 3D creation. Our method shares a similar spirit, which distills the knowledge from the generator's 2D super-resolution branch to its 3D rendering branch, thus achieving image generation with both photorealism and strict 3D consistency." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 669, + 115, + 682 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 669, + 115, + 682 + ], + "spans": [ + { + "bbox": [ + 47, + 669, + 115, + 682 + ], + "type": "text", + "content": "3. Approach" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "text", + "content": "Given a collection of 2D images, we aim to learn a 3D-aware generator " + }, + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "inline_equation", + "content": "G" + }, + { + "bbox": [ + 47, + 689, + 287, + 715 + ], + "type": "text", + "content": " for free-view image synthesis. The gen" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 305, + 72, + 545, + 97 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 97 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 97 + ], + "type": "text", + "content": "erator takes a random code " + }, + { + "bbox": [ + 305, + 72, + 545, + 97 + ], + "type": "inline_equation", + "content": "z \\in \\mathbb{R}^{d_z}" + }, + { + "bbox": [ + 305, + 72, + 545, + 97 + ], + "type": "text", + "content": " and an explicit camera pose " + }, + { + "bbox": [ + 305, + 72, + 545, + 97 + ], + "type": "inline_equation", + "content": "\\theta \\in \\mathbb{R}^{d_{\\theta}}" + }, + { + "bbox": [ + 305, + 72, + 545, + 97 + ], + "type": "text", + "content": " as input, and generates a 2D image " + }, + { + "bbox": [ + 305, + 72, + 545, + 97 + ], + "type": "inline_equation", + "content": "I" + }, + { + "bbox": [ + 305, + 72, + 545, + 97 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 337, + 103, + 545, + 118 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 337, + 103, + 545, + 118 + ], + "spans": [ + { + "bbox": [ + 337, + 103, + 545, + 118 + ], + "type": "interline_equation", + "content": "G: (\\boldsymbol {z}, \\boldsymbol {\\theta}) \\in \\mathbb {R} ^ {d _ {z}} \\times \\mathbb {R} ^ {d _ {\\theta}} \\rightarrow I \\in \\mathbb {R} ^ {H \\times W \\times 3}. \\tag {1}", + "image_path": "b9f95b428442888479205774c43e5a80286e50bc732c9ec52fcc2c55ea0b358b.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 126, + 547, + 319 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 126, + 547, + 319 + ], + "spans": [ + { + "bbox": [ + 304, + 126, + 547, + 319 + ], + "type": "text", + "content": "To enable high-quality image synthesis, we adopt EG3D [3] as the backbone of the generator, which synthesizes low-resolution feature fields via the tri-plane representation [3], and leverages 2D super-resolution for high-resolution image generation (Sec. 3.1). Based on EG3D, we propose a 3D-to-2D imitation strategy to synthesize high-resolution NeRF for 3D-consistent image rendering. We leverage a 3D super-resolution branch to predict high-resolution triplanes from the low-resolution ones, and force the rendered images from the former to mimic the images generated by the 2D super-resolution branch (Sec. 3.2). In addition, we introduce 3D-aware convolution [44] to the generator for better tri-plane learning via cross-plane communications, which helps to further improve the image generation quality (Sec. 3.3). The overview of our method is illustrated in Fig. 3. We describe each part in detail below." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 325, + 429, + 337 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 325, + 429, + 337 + ], + "spans": [ + { + "bbox": [ + 306, + 325, + 429, + 337 + ], + "type": "text", + "content": "3.1. Preliminaries: EG3D" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "spans": [ + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "text", + "content": "EG3D adopts a StyleGAN2-based [18] generator " + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "inline_equation", + "content": "\\mathcal{E}" + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "text", + "content": " to efficiently synthesize the low-resolution feature field of a subject. The feature field is represented by the tri-plane representation which consists of three orthogonal 2D planes produced by reshaping the output feature map of " + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "inline_equation", + "content": "\\mathcal{E}" + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "text", + "content": ", given the latent code " + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "text", + "content": " as input. For a point " + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "inline_equation", + "content": "\\pmb{x} \\in \\mathbb{R}^3" + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "text", + "content": " in the 3D space, its corresponding feature " + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "inline_equation", + "content": "\\mathbf{f}" + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "text", + "content": " can be obtained by projecting itself onto the three planes " + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{xy}, \\mathbf{P}_{yz}, \\mathbf{P}_{zx}" + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "text", + "content": ", and summing the retrieved features " + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "inline_equation", + "content": "\\mathbf{f}_{xy}, \\mathbf{f}_{yz}, \\mathbf{f}_{zx}" + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "text", + "content": ". A small MLP " + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "inline_equation", + "content": "\\mathcal{M}" + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "text", + "content": " then maps this intermediate feature to volume density " + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "inline_equation", + "content": "\\sigma \\in \\mathbb{R}" + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "text", + "content": " and color feature " + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "inline_equation", + "content": "\\pmb{c} \\in \\mathbb{R}^{d_c}" + }, + { + "bbox": [ + 304, + 343, + 545, + 487 + ], + "type": "text", + "content": " (the first three dimensions represent RGB color), forming the low-resolution feature field:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 353, + 495, + 545, + 510 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 353, + 495, + 545, + 510 + ], + "spans": [ + { + "bbox": [ + 353, + 495, + 545, + 510 + ], + "type": "interline_equation", + "content": "\\mathcal {M}: \\mathbf {f} \\in \\mathbb {R} ^ {d ^ {\\mathbf {f}}} \\rightarrow (c, \\sigma) \\in \\mathbb {R} ^ {d ^ {c}} \\times \\mathbb {R}. \\tag {2}", + "image_path": "be7dca79106c1d9ed0700ed5ad45a21aec6fd92340c0af8d143ee0036ea4883e.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 514, + 545, + 563 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 514, + 545, + 563 + ], + "spans": [ + { + "bbox": [ + 304, + 514, + 545, + 563 + ], + "type": "text", + "content": "To generate high-resolution images, EG3D enforces volume rendering [14, 23] to render the above feature field to a low-resolution feature map " + }, + { + "bbox": [ + 304, + 514, + 545, + 563 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 304, + 514, + 545, + 563 + ], + "type": "text", + "content": ", where each pixel value " + }, + { + "bbox": [ + 304, + 514, + 545, + 563 + ], + "type": "inline_equation", + "content": "C(\\boldsymbol{r})" + }, + { + "bbox": [ + 304, + 514, + 545, + 563 + ], + "type": "text", + "content": " corresponding to a viewing ray " + }, + { + "bbox": [ + 304, + 514, + 545, + 563 + ], + "type": "inline_equation", + "content": "\\boldsymbol{r}" + }, + { + "bbox": [ + 304, + 514, + 545, + 563 + ], + "type": "text", + "content": " can be obtained via" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 310, + 569, + 545, + 600 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 569, + 545, + 600 + ], + "spans": [ + { + "bbox": [ + 310, + 569, + 545, + 600 + ], + "type": "interline_equation", + "content": "C (\\boldsymbol {r}) = \\sum_ {i = 1} ^ {N} T _ {i} (1 - \\exp (- \\sigma_ {i} \\delta_ {i})) \\boldsymbol {c} _ {i}, T _ {i} = \\exp (- \\sum_ {j = 1} ^ {i - 1} \\sigma_ {j} \\delta_ {j}). \\tag {3}", + "image_path": "aff3d2a664bd3f930ddb01e957b0805be474a8fbdd638be16626e19e580420b5.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "text", + "content": "Here, " + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "text", + "content": " is the index of points along ray " + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "text", + "content": " sorted from near to far, and " + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "inline_equation", + "content": "\\delta" + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "text", + "content": " is the distance between adjacent points. Then, the rendered feature map " + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "inline_equation", + "content": "C" + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "text", + "content": " is sent to a 2D super-resolution module " + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "inline_equation", + "content": "S^{2D}" + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "text", + "content": " consisting of several StyleGAN2-modulated convolutional layers to generate the final image " + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "inline_equation", + "content": "I^{2D}" + }, + { + "bbox": [ + 304, + 605, + 545, + 666 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 666, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 666, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 666, + 545, + 713 + ], + "type": "text", + "content": "Although EG3D can generate free-view images of high quality, it cannot well maintain their 3D consistency across different views. This is inevitable due to incorporating the black-box CNN-based 2D super-resolution mod" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2340" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 53, + 71, + 542, + 229 + ], + "blocks": [ + { + "bbox": [ + 53, + 71, + 542, + 229 + ], + "lines": [ + { + "bbox": [ + 53, + 71, + 542, + 229 + ], + "spans": [ + { + "bbox": [ + 53, + 71, + 542, + 229 + ], + "type": "image", + "image_path": "73f98d857ddebfbcedb1e09800685ca779ed89a8f976f62879b902a03cc5138b.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 232, + 547, + 266 + ], + "lines": [ + { + "bbox": [ + 46, + 232, + 547, + 266 + ], + "spans": [ + { + "bbox": [ + 46, + 232, + 547, + 266 + ], + "type": "text", + "content": "Figure 3. Overview of our framework. 3D-to-2D imitation strategy is enforced to let the generator's 3D branch to mimic the results of its 2D branch, thus leading to image generation of high quality and strict 3D consistency. 3D-aware convolutions are also introduced to the tri-plane generator to enhance 3D representation learning, which further improves the image generation quality." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 284, + 289, + 416 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 284, + 289, + 416 + ], + "spans": [ + { + "bbox": [ + 46, + 284, + 289, + 416 + ], + "type": "text", + "content": "ule, which breaks the physical rules of the volume rendering process. Despite that EG3D further proposes a dual-discrimination [3] strategy to force the high-resolution images to be consistent with their low-resolution counterparts, detail-level 3D inconsistency (i.e. texture flickering) still cannot be eliminated. During continuous camera variation, these artifacts can be easily captured by human eyes, differing the synthesized results from a real video sequence. To maintain the 3D consistency meanwhile keep the high-quality image generation to the maximum extent, we propose a 3D-to-2D imitation strategy described below." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 423, + 160, + 435 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 423, + 160, + 435 + ], + "spans": [ + { + "bbox": [ + 47, + 423, + 160, + 435 + ], + "type": "text", + "content": "3.2. 3D-to-2D Imitation" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 442, + 287, + 574 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 442, + 287, + 574 + ], + "spans": [ + { + "bbox": [ + 46, + 442, + 287, + 574 + ], + "type": "text", + "content": "To keep the strict 3D consistency, a better way is to directly render the 3D representation instead of resorting to a 2D CNN for image synthesis. Noticing that the images generated by EG3D contain rich details, it is natural to use them as guidance for images synthesized by direct 3D rendering. If the directly-rendered images well mimic those fine details, their quality should get very close to that of EG3D. Meanwhile, since they are rendered from a continuous 3D representation, their 3D consistency across different views should be trivially maintained. This motivates us to design the 3D-to-2D imitation strategy, as depicted in Fig. 3." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 574, + 287, + 610 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 574, + 287, + 610 + ], + "spans": [ + { + "bbox": [ + 46, + 574, + 287, + 610 + ], + "type": "text", + "content": "Specifically, we introduce a 3D super-resolution module " + }, + { + "bbox": [ + 46, + 574, + 287, + 610 + ], + "type": "inline_equation", + "content": "S^{3D}" + }, + { + "bbox": [ + 46, + 574, + 287, + 610 + ], + "type": "text", + "content": " to generate residual tri-planes " + }, + { + "bbox": [ + 46, + 574, + 287, + 610 + ], + "type": "inline_equation", + "content": "\\mathbf{P}^r" + }, + { + "bbox": [ + 46, + 574, + 287, + 610 + ], + "type": "text", + "content": " from the coarse tri-planes " + }, + { + "bbox": [ + 46, + 574, + 287, + 610 + ], + "type": "inline_equation", + "content": "\\mathbf{P}^c" + }, + { + "bbox": [ + 46, + 574, + 287, + 610 + ], + "type": "text", + "content": " produced by the tri-plane generator " + }, + { + "bbox": [ + 46, + 574, + 287, + 610 + ], + "type": "inline_equation", + "content": "\\mathcal{E}" + }, + { + "bbox": [ + 46, + 574, + 287, + 610 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 59, + 617, + 287, + 633 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 617, + 287, + 633 + ], + "spans": [ + { + "bbox": [ + 59, + 617, + 287, + 633 + ], + "type": "interline_equation", + "content": "\\mathcal {S} ^ {3 D}: \\mathbf {P} ^ {c} \\in \\mathbb {R} ^ {3 \\times H ^ {c} \\times W ^ {c} \\times d ^ {\\mathbf {f}}} \\rightarrow \\mathbf {P} ^ {r} \\in \\mathbb {R} ^ {3 \\times H ^ {r} \\times W ^ {r} \\times d ^ {\\mathbf {f}}}. \\tag {4}", + "image_path": "6dbe3f556c7ec6d9a2316b003cff0a598659a53ab9e14fc3d343c7dd76a3943d.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "type": "text", + "content": "The " + }, + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "type": "inline_equation", + "content": "S^{3D}" + }, + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "type": "text", + "content": " adopts several StyleGAN2-modulated convolutional layers conditioned on a latent code " + }, + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\pmb{w}" + }, + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "type": "text", + "content": " mapped from the random code " + }, + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "type": "inline_equation", + "content": "\\pmb{z}" + }, + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "type": "text", + "content": ", similar to the 2D super-resolution module " + }, + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "type": "inline_equation", + "content": "S^{2D}" + }, + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "type": "text", + "content": " in EG3D. The difference is that " + }, + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "type": "inline_equation", + "content": "S^{3D}" + }, + { + "bbox": [ + 46, + 640, + 288, + 715 + ], + "type": "text", + "content": " conducts super-resolution on the triplane-based 3D representation instead of the rendered 2D feature map. In this way, we can" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "spans": [ + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "text", + "content": "generate a high-resolution 3D field for direct 3D rendering. Given the coarse and residual tri-planes (i.e. " + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "inline_equation", + "content": "\\mathbf{P}^c" + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "inline_equation", + "content": "\\mathbf{P}^r" + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "text", + "content": "), we obtain a more detailed intermediate feature " + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "inline_equation", + "content": "\\mathbf{f} = \\mathbf{f}^c + \\mathbf{f}^r" + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "text", + "content": " for a 3D point " + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "text", + "content": ", and further obtain the high-resolution feature field by sending the intermediate feature into the MLP-based decoder " + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "inline_equation", + "content": "\\mathcal{M}" + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "text", + "content": " following Eq. (2). The first three feature dimensions of the field derive the high-resolution NeRF for rendering 3D-consistent fine image " + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "inline_equation", + "content": "I^{3D}" + }, + { + "bbox": [ + 304, + 284, + 545, + 380 + ], + "type": "text", + "content": " via Eq. (3)." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "spans": [ + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "text", + "content": "To ensure that " + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "inline_equation", + "content": "I^{3D}" + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "text", + "content": " contains reasonable geometry structure with rich texture details, we let it to mimic the contents of " + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "inline_equation", + "content": "I^{2D}" + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "text", + "content": " generated by the 2D branch " + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "inline_equation", + "content": "S^{2D}" + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "text", + "content": ". For a pair of " + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "inline_equation", + "content": "I^{3D}" + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "inline_equation", + "content": "I^{2D}" + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "text", + "content": " synthesized with the same latent code " + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "text", + "content": " and camera pose " + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 304, + 384, + 546, + 456 + ], + "type": "text", + "content": ", we enforce imitation loss between them to guarantee their perceptual similarity:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 349, + 475, + 545, + 489 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 349, + 475, + 545, + 489 + ], + "spans": [ + { + "bbox": [ + 349, + 475, + 545, + 489 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {i m i t a t i o n}} = \\operatorname {L P I P S} \\left(I ^ {3 D}, \\operatorname {s g} \\left(I ^ {2 D}\\right)\\right), \\tag {5}", + "image_path": "6732b03b48147acf8d050a16eaf7cb136d097cf6f78d562707fa3f5800610826.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "spans": [ + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "inline_equation", + "content": "\\mathrm{LPIPS}(\\cdot ,\\cdot)" + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "text", + "content": " is the perceptual loss defined in [49], and sg denotes stopping gradient to avoid undesired influence of " + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "inline_equation", + "content": "I^{3D}" + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "text", + "content": " on the 2D branch. This process is very similar to a standard multiview reconstruction process. During training, " + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "inline_equation", + "content": "I^{2D}" + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "text", + "content": " sharing the same code " + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "inline_equation", + "content": "\\mathbf{z}" + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "text", + "content": " are generated under different camera views from a statistical aspect, forming the multiview supervision. The high-resolution NeRF from the 3D branch renders " + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "inline_equation", + "content": "I^{3D}" + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "text", + "content": " under the same camera views to compare with the multiview data for 3D reconstruction. Considering that " + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "inline_equation", + "content": "I^{2D}" + }, + { + "bbox": [ + 304, + 505, + 546, + 636 + ], + "type": "text", + "content": " are nearly 3D-consistent, they should help to learn a reasonable NeRF for 3D-consistent image rendering." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "text", + "content": "Nevertheless, since " + }, + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "inline_equation", + "content": "I^{2D}" + }, + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "text", + "content": " are not strictly 3D-consistent, faithfully reconstructing their image contents leads to blurry results where the texture details across different views are averaged out. Therefore, we further introduce the non-saturating GAN loss with R1 regularization [21] between " + }, + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "inline_equation", + "content": "I^{3D}" + }, + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "text", + "content": " and real images " + }, + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "inline_equation", + "content": "\\hat{I}" + }, + { + "bbox": [ + 304, + 641, + 547, + 714 + ], + "type": "text", + "content": " to maintain the high-frequency de" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "2341" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 69, + 82 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 69, + 82 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 69, + 82 + ], + "type": "text", + "content": "tails:" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 55, + 89, + 287, + 122 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 89, + 287, + 122 + ], + "spans": [ + { + "bbox": [ + 55, + 89, + 287, + 122 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {L} _ {a d v} ^ {3 D} = \\mathbb {E} _ {\\boldsymbol {z} \\sim p _ {z}, \\boldsymbol {\\theta} \\sim p _ {\\theta}} [ f (D ^ {3 D} (G ^ {3 D} (\\boldsymbol {z}, \\boldsymbol {\\theta}))) ] \\tag {6} \\\\ + \\mathbb {E} _ {\\hat {I} \\sim p _ {r e a l}} [ f (- D ^ {3 D} (\\hat {I})) + \\lambda \\| \\nabla D ^ {3 D} (\\hat {I})) \\| ^ {2} ], \\\\ \\end{array}", + "image_path": "f3e5028b7ff1da7be649a0524665f1e1d134308ae48fea9306fdf665f3fa4d95.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 127, + 287, + 163 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 127, + 287, + 163 + ], + "spans": [ + { + "bbox": [ + 47, + 127, + 287, + 163 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 127, + 287, + 163 + ], + "type": "inline_equation", + "content": "f(u) = \\log (1 + \\exp (u))" + }, + { + "bbox": [ + 47, + 127, + 287, + 163 + ], + "type": "text", + "content": " is the Softplus function, " + }, + { + "bbox": [ + 47, + 127, + 287, + 163 + ], + "type": "inline_equation", + "content": "G^{3D}" + }, + { + "bbox": [ + 47, + 127, + 287, + 163 + ], + "type": "text", + "content": " including " + }, + { + "bbox": [ + 47, + 127, + 287, + 163 + ], + "type": "inline_equation", + "content": "\\{\\mathcal{E},\\mathcal{M},\\mathcal{S}^{3D}\\}" + }, + { + "bbox": [ + 47, + 127, + 287, + 163 + ], + "type": "text", + "content": " is the 3D rendering branch of the generator, and " + }, + { + "bbox": [ + 47, + 127, + 287, + 163 + ], + "type": "inline_equation", + "content": "D^{3D}" + }, + { + "bbox": [ + 47, + 127, + 287, + 163 + ], + "type": "text", + "content": " is the corresponding discriminator." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 163, + 287, + 258 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 163, + 287, + 258 + ], + "spans": [ + { + "bbox": [ + 46, + 163, + 287, + 258 + ], + "type": "text", + "content": "An advantage of the above imitation learning is that we can render small patches (i.e. " + }, + { + "bbox": [ + 46, + 163, + 287, + 258 + ], + "type": "inline_equation", + "content": "64 \\times 64" + }, + { + "bbox": [ + 46, + 163, + 287, + 258 + ], + "type": "text", + "content": ") to compute Eq. (5) and Eq. (6), as shown in Fig. 3, with only minor influence to the final image quality. This largely reduces the memory cost during training and enables learning the 3D branch at high resolution (e.g. " + }, + { + "bbox": [ + 46, + 163, + 287, + 258 + ], + "type": "inline_equation", + "content": "512 \\times 512" + }, + { + "bbox": [ + 46, + 163, + 287, + 258 + ], + "type": "text", + "content": "). By contrast, solely applying adversarial loss at patch-level often leads to large quality drops as shown in previous methods [35, 41] and Tab. 2." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 259, + 287, + 295 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 259, + 287, + 295 + ], + "spans": [ + { + "bbox": [ + 46, + 259, + 287, + 295 + ], + "type": "text", + "content": "Finally, we apply image-level adversarial loss to the 2D branch following EG3D to ensure that " + }, + { + "bbox": [ + 46, + 259, + 287, + 295 + ], + "type": "inline_equation", + "content": "I^{2D}" + }, + { + "bbox": [ + 46, + 259, + 287, + 295 + ], + "type": "text", + "content": ", as the supervision for the 3D branch, are of high quality:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 55, + 312, + 287, + 344 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 55, + 312, + 287, + 344 + ], + "spans": [ + { + "bbox": [ + 55, + 312, + 287, + 344 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {L} _ {a d v} ^ {2 D} = \\mathbb {E} _ {\\boldsymbol {z} \\sim p _ {z}, \\boldsymbol {\\theta} \\sim p _ {\\theta}} [ f (D ^ {2 D} (G ^ {2 D} (\\boldsymbol {z}, \\boldsymbol {\\theta}))) ] \\tag {7} \\\\ + \\mathbb {E} _ {I \\sim p _ {r e a l}} [ f (- D ^ {2 D} (\\hat {I})) + \\lambda \\| \\nabla D ^ {2 D} (\\hat {I})) \\| ^ {2} ], \\\\ \\end{array}", + "image_path": "a209cf1753dc09548bc0f9a602d6dbab1f59642bbabbffa546376d4abe5fd730.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 349, + 287, + 385 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 349, + 287, + 385 + ], + "spans": [ + { + "bbox": [ + 47, + 349, + 287, + 385 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 349, + 287, + 385 + ], + "type": "inline_equation", + "content": "G^{2D}" + }, + { + "bbox": [ + 47, + 349, + 287, + 385 + ], + "type": "text", + "content": " is the 2D branch generator consisting of " + }, + { + "bbox": [ + 47, + 349, + 287, + 385 + ], + "type": "inline_equation", + "content": "\\{\\mathcal{E},\\mathcal{M},\\mathcal{S}^{2D}\\}" + }, + { + "bbox": [ + 47, + 349, + 287, + 385 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 47, + 349, + 287, + 385 + ], + "type": "inline_equation", + "content": "D^{2D}" + }, + { + "bbox": [ + 47, + 349, + 287, + 385 + ], + "type": "text", + "content": " is the corresponding discriminator. The same dual discrimination is adopted as done in EG3D." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 59, + 386, + 192, + 397 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 386, + 192, + 397 + ], + "spans": [ + { + "bbox": [ + 59, + 386, + 192, + 397 + ], + "type": "text", + "content": "Overall, the training objective is" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 91, + 404, + 287, + 419 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 91, + 404, + 287, + 419 + ], + "spans": [ + { + "bbox": [ + 91, + 404, + 287, + 419 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {t o t a l}} = \\mathcal {L} _ {\\text {i m i t a t i o n}} + \\mathcal {L} _ {\\text {a d v}} ^ {3 D} + \\mathcal {L} _ {\\text {a d v}} ^ {2 D}. \\tag {8}", + "image_path": "4982faa559f46cec1373b0cc2234551b42dfc854a6311f630fb5ca6deb9af32b.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 424, + 287, + 473 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 424, + 287, + 473 + ], + "spans": [ + { + "bbox": [ + 46, + 424, + 287, + 473 + ], + "type": "text", + "content": "In practice, we first learn the 2D branch via " + }, + { + "bbox": [ + 46, + 424, + 287, + 473 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{adv}^{2D}" + }, + { + "bbox": [ + 46, + 424, + 287, + 473 + ], + "type": "text", + "content": " to obtain reasonable synthesized images " + }, + { + "bbox": [ + 46, + 424, + 287, + 473 + ], + "type": "inline_equation", + "content": "I^{2D}" + }, + { + "bbox": [ + 46, + 424, + 287, + 473 + ], + "type": "text", + "content": ", then leverage " + }, + { + "bbox": [ + 46, + 424, + 287, + 473 + ], + "type": "inline_equation", + "content": "\\mathcal{L}_{total}" + }, + { + "bbox": [ + 46, + 424, + 287, + 473 + ], + "type": "text", + "content": " to simultaneously learn the 2D and 3D branches for high-quality and 3D-consistent image synthesis." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 479, + 216, + 491 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 479, + 216, + 491 + ], + "spans": [ + { + "bbox": [ + 47, + 479, + 216, + 491 + ], + "type": "text", + "content": "3.3. 3D-Aware Tri-Plane Generator" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "type": "text", + "content": "As depicted in Sec. 3.2, the tri-plane generator " + }, + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{E}" + }, + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "type": "text", + "content": " is responsible for synthesizing the coarse tri-planes " + }, + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{P}^c" + }, + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "type": "text", + "content": " shared by both the 2D and 3D branches, which is an important component that would affect the final image generation quality. However, in EG3D, " + }, + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{E}" + }, + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "type": "text", + "content": " takes a StyleGAN2 architecture originally designed for 2D generative tasks. As shown in Fig. 4(a), the original tri-plane generator only contains the main stream and the output stream. The tri-planes are obtained from latent feature maps in the main stream via 2D convolutions (i.e. toRGB layers), and the latent feature maps are also produced by a serials of 2D synthesis blocks. Consequently, the latent feature maps are forced to learn 3D unaligned features of the three orthogonal planes and the latters also lack feature communications with each other. Inspired by a recent 3D diffusion model [44], we introduce 3D-aware convolutions into our tri-plane generator " + }, + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "type": "inline_equation", + "content": "\\mathcal{E}" + }, + { + "bbox": [ + 46, + 498, + 287, + 713 + ], + "type": "text", + "content": " to enhance feature communications between 3D-associated positions across different planes, for better tri-plane generation." + } + ] + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 310, + 70, + 529, + 186 + ], + "blocks": [ + { + "bbox": [ + 310, + 70, + 529, + 186 + ], + "lines": [ + { + "bbox": [ + 310, + 70, + 529, + 186 + ], + "spans": [ + { + "bbox": [ + 310, + 70, + 529, + 186 + ], + "type": "image", + "image_path": "70f80d0b4d1fceca7c9ccc518d9a3bf59cdca62cfbbad2b6ca2e50532f003be3.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 306, + 190, + 544, + 291 + ], + "blocks": [ + { + "bbox": [ + 306, + 190, + 544, + 291 + ], + "lines": [ + { + "bbox": [ + 306, + 190, + 544, + 291 + ], + "spans": [ + { + "bbox": [ + 306, + 190, + 544, + 291 + ], + "type": "image", + "image_path": "d96d7a3b654a58ecadfc4215cbb0d516c8587ee41a74d2cd7ce571f163e4bbb8.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 294, + 545, + 318 + ], + "lines": [ + { + "bbox": [ + 305, + 294, + 545, + 318 + ], + "spans": [ + { + "bbox": [ + 305, + 294, + 545, + 318 + ], + "type": "text", + "content": "Figure 4. (a) Structure of our 3D-aware tri-plane generator. (b) Operations of the 3D-aware block on " + }, + { + "bbox": [ + 305, + 294, + 545, + 318 + ], + "type": "inline_equation", + "content": "xy" + }, + { + "bbox": [ + 305, + 294, + 545, + 318 + ], + "type": "text", + "content": " plane." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "spans": [ + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": "Specifically, as illustrated in Fig. 4(a), we add an extra 3D-aware stream upon the original output stream after each toRGB layer at different resolutions. At each resolution level " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": ", the corresponding tri-planes " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_k = [\\mathbf{P}_{k,xy},\\mathbf{P}_{k,yz},\\mathbf{P}_{k,zx}]" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": ", are summed with the tri-planes produced by the original output stream, and further sent into a 3D-aware block to produce tri-plane features for the next level. The 3D-aware block conducts similar operations on each of the three planes. For brevity, we omit the subscript " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " here and take " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{xy}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " as an example to illustrate the operation process. As shown in Fig. 4(b), to align " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{yz}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{zx}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " towards " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{xy}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": ", we first perform global pooling along " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " axis of the former two to obtain " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": "-squeezed feature vectors. These vectors are then repeated along the " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " dimension to restore the original spatial size, denoted as " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{yr}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{rx}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": ". In this manner, the obtained " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{yr}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{rx}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " are aligned with " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{xy}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " from a 3D perspective, i.e., a 2D position " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "uv" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " on " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{xy}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " is responsible for features in region " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "uvz, z \\in [z_{min}, z_{max}]" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " in the 3D space, meanwhile the same " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "uv" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " position on " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{yr}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{rx}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " also associate with the features in this 3D region. As a result, we can simply concatenate them along the channel dimension as " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "[\\mathbf{P}_{xy},\\mathbf{P}_{yr},\\mathbf{P}_{rx}]" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": ", and perform modulated 2D convolution [18] on it. The 2D convolution aggregates the 3D-associated features to produce next-level " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{xy}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": ", leading to better feature communications across the planes. " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{yz}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_{zx}" + }, + { + "bbox": [ + 304, + 341, + 546, + 652 + ], + "type": "text", + "content": " can be processed similarly." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 653, + 545, + 713 + ], + "type": "text", + "content": "Note that in [44], the 3D-aware convolution is applied in all layers in a U-Net structure. However, in our scenario, leveraging 3D-aware convolution for all layers, especially the main stream, introduces unaffordable memory cost during training, as it would produce multiple auxiliary tensors" + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2342" + } + ] + } + ], + "index": 17 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 81, + 291, + 241 + ], + "blocks": [ + { + "bbox": [ + 159, + 72, + 181, + 79 + ], + "lines": [ + { + "bbox": [ + 159, + 72, + 181, + 79 + ], + "spans": [ + { + "bbox": [ + 159, + 72, + 181, + 79 + ], + "type": "text", + "content": "EG3D" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 49, + 81, + 291, + 241 + ], + "lines": [ + { + "bbox": [ + 49, + 81, + 291, + 241 + ], + "spans": [ + { + "bbox": [ + 49, + 81, + 291, + 241 + ], + "type": "image", + "image_path": "9b710f27b2d8d9add99a85e353e11d3b1a178adb62dc7a5dff1aecaa3ea1be49.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 304, + 81, + 544, + 241 + ], + "blocks": [ + { + "bbox": [ + 395, + 72, + 452, + 80 + ], + "lines": [ + { + "bbox": [ + 395, + 72, + 452, + 80 + ], + "spans": [ + { + "bbox": [ + 395, + 72, + 452, + 80 + ], + "type": "text", + "content": "Ours (3D branch)" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 304, + 81, + 544, + 241 + ], + "lines": [ + { + "bbox": [ + 304, + 81, + 544, + 241 + ], + "spans": [ + { + "bbox": [ + 304, + 81, + 544, + 241 + ], + "type": "image", + "image_path": "330f4b7d46f9e0a6aa6ea432c37745412866796eebf6c97f4b9ca11b112a85e3.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 243, + 546, + 266 + ], + "lines": [ + { + "bbox": [ + 46, + 243, + 546, + 266 + ], + "spans": [ + { + "bbox": [ + 46, + 243, + 546, + 266 + ], + "type": "text", + "content": "Figure 5. Comparison between our method and EG3D on FFHQ at " + }, + { + "bbox": [ + 46, + 243, + 546, + 266 + ], + "type": "inline_equation", + "content": "512 \\times 512" + }, + { + "bbox": [ + 46, + 243, + 546, + 266 + ], + "type": "text", + "content": " resolution. Our method generates images with comparable quality to those of EG3D, while producing 3D geometries with finer details and multiview sequences with better 3D-consistency." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 50, + 287, + 214, + 342 + ], + "blocks": [ + { + "bbox": [ + 121, + 277, + 141, + 285 + ], + "lines": [ + { + "bbox": [ + 121, + 277, + 141, + 285 + ], + "spans": [ + { + "bbox": [ + 121, + 277, + 141, + 285 + ], + "type": "text", + "content": "GMPI" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 50, + 287, + 214, + 342 + ], + "lines": [ + { + "bbox": [ + 50, + 287, + 214, + 342 + ], + "spans": [ + { + "bbox": [ + 50, + 287, + 214, + 342 + ], + "type": "image", + "image_path": "6668d0c6ba3449c6a90f57a81e805ab39799784708cf66b7c208a41a3cf405a8.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 215, + 287, + 379, + 342 + ], + "blocks": [ + { + "bbox": [ + 279, + 277, + 312, + 287 + ], + "lines": [ + { + "bbox": [ + 279, + 277, + 312, + 287 + ], + "spans": [ + { + "bbox": [ + 279, + 277, + 312, + 287 + ], + "type": "text", + "content": "EpiGRAF" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 215, + 287, + 379, + 342 + ], + "lines": [ + { + "bbox": [ + 215, + 287, + 379, + 342 + ], + "spans": [ + { + "bbox": [ + 215, + 287, + 379, + 342 + ], + "type": "image", + "image_path": "144f4379c2bf7de7bfede9eb56f646ce71bc5594da7032ad790d416ac3f7e749.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 345, + 546, + 356 + ], + "lines": [ + { + "bbox": [ + 46, + 345, + 546, + 356 + ], + "spans": [ + { + "bbox": [ + 46, + 345, + 546, + 356 + ], + "type": "text", + "content": "Figure 6. Comparison between our method and other 3D rendering baselines on FFHQ at " + }, + { + "bbox": [ + 46, + 345, + 546, + 356 + ], + "type": "inline_equation", + "content": "512 \\times 512" + }, + { + "bbox": [ + 46, + 345, + 546, + 356 + ], + "type": "text", + "content": " resolution. Best viewed with zoom-in." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 380, + 287, + 544, + 342 + ], + "blocks": [ + { + "bbox": [ + 434, + 278, + 490, + 287 + ], + "lines": [ + { + "bbox": [ + 434, + 278, + 490, + 287 + ], + "spans": [ + { + "bbox": [ + 434, + 278, + 490, + 287 + ], + "type": "text", + "content": "Ours (3D branch)" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 380, + 287, + 544, + 342 + ], + "lines": [ + { + "bbox": [ + 380, + 287, + 544, + 342 + ], + "spans": [ + { + "bbox": [ + 380, + 287, + 544, + 342 + ], + "type": "image", + "image_path": "f12d8146a65bc2ede645a372ed80dbeae1ab3ec63075360e29ed3b8f42fd1f73.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 377, + 287, + 485 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 377, + 287, + 485 + ], + "spans": [ + { + "bbox": [ + 46, + 377, + 287, + 485 + ], + "type": "text", + "content": "and triples the channel dimension for each processed latent feature map, as shown in Fig. 4(b). Comparing to the latent feature maps in the main stream, the tri-planes after each output layer contains much fewer channels thus more memory-friendly to adopt the 3D-aware convolution. Empirically, our proposed 3D-aware stream helps to learn more reasonable tri-planes and improves the final image generation quality, with only a minor increase in the total memory consumption (see Sec. 4.3)." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 47, + 500, + 128, + 514 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 500, + 128, + 514 + ], + "spans": [ + { + "bbox": [ + 47, + 500, + 128, + 514 + ], + "type": "text", + "content": "4. Experiments" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 521, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 521, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 521, + 288, + 713 + ], + "type": "text", + "content": "Implementation details. We train our method on two real-world datasets: FFHQ [17] and AFHQ-v2 Cats [5], which consists of 70K human face images of " + }, + { + "bbox": [ + 46, + 521, + 288, + 713 + ], + "type": "inline_equation", + "content": "1024^2" + }, + { + "bbox": [ + 46, + 521, + 288, + 713 + ], + "type": "text", + "content": " resolution and 5.5K cat face images of " + }, + { + "bbox": [ + 46, + 521, + 288, + 713 + ], + "type": "inline_equation", + "content": "512^2" + }, + { + "bbox": [ + 46, + 521, + 288, + 713 + ], + "type": "text", + "content": " resolution, respectively. We follow the data pre-processing of EG3D [3] to crop and resize the images to " + }, + { + "bbox": [ + 46, + 521, + 288, + 713 + ], + "type": "inline_equation", + "content": "256^2" + }, + { + "bbox": [ + 46, + 521, + 288, + 713 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 46, + 521, + 288, + 713 + ], + "type": "inline_equation", + "content": "512^2" + }, + { + "bbox": [ + 46, + 521, + 288, + 713 + ], + "type": "text", + "content": " resolution. Experiments are conducted on 8 NVIDIA Tesla A100 GPUs with 40GB memory, following the training configuration of EG3D. For FFHQ, the training process takes around 8 days, where learning the 2D branch takes 5 days and jointly training the whole framework takes additional 3 days. For AFHQ-v2, we finetune the 2D branch initially trained on FFHQ for 1 day, then jointly train the whole framework for extra 3 days. Adaptive data augmentation [15] is applied to AFHQ-v2 to facilitate training with limited data. See the suppl. material for more details." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 376, + 394, + 388 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 376, + 394, + 388 + ], + "spans": [ + { + "bbox": [ + 306, + 376, + 394, + 388 + ], + "type": "text", + "content": "4.1. Visual Results" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 396, + 546, + 468 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 396, + 546, + 468 + ], + "spans": [ + { + "bbox": [ + 305, + 396, + 546, + 468 + ], + "type": "text", + "content": "Figure 2 shows the multiview images generated by our 3D branch generator. It can produce high-quality images with fine details at a resolution of " + }, + { + "bbox": [ + 305, + 396, + 546, + 468 + ], + "type": "inline_equation", + "content": "512^2" + }, + { + "bbox": [ + 305, + 396, + 546, + 468 + ], + "type": "text", + "content": ". Moreover, the images are of strict 3D consistency across different views via directly rendering the generated high-resolution NeRF. More results are in Fig. 5, 6, and the suppl. material." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 475, + 462, + 488 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 475, + 462, + 488 + ], + "spans": [ + { + "bbox": [ + 306, + 475, + 462, + 488 + ], + "type": "text", + "content": "4.2. Comparison with Prior Arts" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 494, + 545, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 494, + 545, + 567 + ], + "spans": [ + { + "bbox": [ + 305, + 494, + 545, + 567 + ], + "type": "text", + "content": "Baselines. We compare our method with existing 3D-aware GANs, including methods leveraging 2D superresolution: StyleSDF [27], VolumeGAN [47], StyleN-erF [9], and EG3D [3]; and methods with direct 3D rendering: GRAM [6], GRAM-HD [45], GMPI [52], EpiGRAF [41], and VoxGRAF [36]." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 582, + 547, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 582, + 547, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 582, + 547, + 713 + ], + "type": "text", + "content": "Qualitative comparison. Figure 5 shows the visual comparison between our method and EG3D. Our generated images via direct rendering have comparable quality with those generated by EG3D via 2D super-resolution. We further visualize the 3D geometry and the spatiotemporal texture images [45] of the two methods. The geometry is extracted via Marching Cubes [20] on the density field at " + }, + { + "bbox": [ + 304, + 582, + 547, + 713 + ], + "type": "inline_equation", + "content": "512^{3}" + }, + { + "bbox": [ + 304, + 582, + 547, + 713 + ], + "type": "text", + "content": " resolution. The spatiotemporal textures are obtained by stacking the pixels of a fixed line segment under continuous camera change, very similar to the Epipolar Line Images [1], where smoothly tilted strips indicate better 3D" + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2343" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 78, + 70, + 517, + 215 + ], + "blocks": [ + { + "bbox": [ + 78, + 70, + 517, + 215 + ], + "lines": [ + { + "bbox": [ + 78, + 70, + 517, + 215 + ], + "spans": [ + { + "bbox": [ + 78, + 70, + 517, + 215 + ], + "type": "table", + "html": "
MethodFFHQ256FFHQ512CATS256CATS512
FID ↓PSNR\\( _{mv} \\) ↑SSIM\\( _{mv} \\) ↑FID ↓PSNR\\( _{mv} \\) ↑SSIM\\( _{mv} \\) ↑FID ↓FID ↓
w/2D SRStyleSDF [27]11.5--11.2---7.91
VolumeGAN [47]9.1033.60.926-----
StyleNeRF [9]8.0031.90.9157.8030.90.843--
EG3D [3]4.8034.00.9284.7032.40.8613.882.77
Ours (2D branch)3.9135.70.9384.1433.30.8913.412.72
w/o 2D SRGRAM [6]13.838.00.966---13.4-
GRAM-HD [45]10.436.50.955----7.67
GMPI [52]11.439.80.9778.2939.00.961-7.79
EpiGRAF [41]9.71--9.9237.30.9496.93-
VoxGRAF [36]9.6037.20.960---9.60-
Ours (3D branch)5.1439.30.9745.3737.80.9554.144.29
", + "image_path": "3e29e00a0d7ba11da4356e06373a73e824983c25fb3f2fa154d4418a9868f6e1.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 107, + 215, + 485, + 225 + ], + "lines": [ + { + "bbox": [ + 107, + 215, + 485, + 225 + ], + "spans": [ + { + "bbox": [ + 107, + 215, + 485, + 225 + ], + "type": "text", + "content": "Table 1. Comparison on image generation quality and 3D consistency among different 3D-aware GANs." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 245, + 287, + 316 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 245, + 287, + 316 + ], + "spans": [ + { + "bbox": [ + 46, + 245, + 287, + 316 + ], + "type": "text", + "content": "consistency. As shown, our geometries contain finer details in that we directly learn the NeRF of a subject at high resolution. Our spatiotemporal textures are also more reasonable with fewer twisted patterns, thanks to the direct 3D rendering for image synthesis instead of using a black-box 2D super-resolution module." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 318, + 287, + 378 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 318, + 287, + 378 + ], + "spans": [ + { + "bbox": [ + 46, + 318, + 287, + 378 + ], + "type": "text", + "content": "Figure 6 compares our method with other 3D baselines on FFHQ at " + }, + { + "bbox": [ + 46, + 318, + 287, + 378 + ], + "type": "inline_equation", + "content": "512^{2}" + }, + { + "bbox": [ + 46, + 318, + 287, + 378 + ], + "type": "text", + "content": " resolution. Visually inspected, our 3D branch produces images of higher fidelity compared to existing methods leveraging direct 3D rendering. More analysis and video results can be found in the suppl. material." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 384, + 287, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 384, + 287, + 552 + ], + "spans": [ + { + "bbox": [ + 46, + 384, + 287, + 552 + ], + "type": "text", + "content": "Quantitative comparison. Table 1 and Fig. 1 show the quantitative results of different methods in terms of image generation quality and 3D consistency. For image generation quality, We calculate the Frechet Inception Distance (FID) [12] between 50K generated images and all available real images in the training set. For 3D consistency, we follow GRAM-HD [45] to generate multiview images of 50 random subjects and train the multiview reconstruction method NeuS [43] on each of them. We report the average PSNR and SSIM scores between our generated multiview images and the re-rendered images of NeuS (denoted as " + }, + { + "bbox": [ + 46, + 384, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mathrm{PSNR}_{mv}" + }, + { + "bbox": [ + 46, + 384, + 287, + 552 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 384, + 287, + 552 + ], + "type": "inline_equation", + "content": "\\mathrm{SSIM}_{mv}" + }, + { + "bbox": [ + 46, + 384, + 287, + 552 + ], + "type": "text", + "content": "). Theoretically, better 3D consistency facilitates the 3D reconstruction process of NeuS, thus leading to higher PSNR and SSIM." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 553, + 287, + 661 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 553, + 287, + 661 + ], + "spans": [ + { + "bbox": [ + 46, + 553, + 287, + 661 + ], + "type": "text", + "content": "As shown, our 2D branch generator demonstrates better results compared to EG3D in all metrics across different datasets, thanks to our 3D-aware stream in the tri-plane generator. Moreover, with the 3D-to-2D imitation strategy, our 3D branch generator largely improves the image generation quality among methods using direct 3D rendering, while maintaining competitive 3D consistency. Its image quality even surpasses most of the methods with 2D superresolution and comes very close to that of EG3D." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 670, + 141, + 683 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 670, + 141, + 683 + ], + "spans": [ + { + "bbox": [ + 47, + 670, + 141, + 683 + ], + "type": "text", + "content": "4.3. Ablation Study" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 287, + 713 + ], + "type": "text", + "content": "We conduct ablation studies to validate the efficacy of our proposed 3D-to-2D imitation and the 3D-aware tri" + } + ] + } + ], + "index": 7 + }, + { + "type": "table", + "bbox": [ + 318, + 243, + 535, + 324 + ], + "blocks": [ + { + "bbox": [ + 318, + 243, + 535, + 324 + ], + "lines": [ + { + "bbox": [ + 318, + 243, + 535, + 324 + ], + "spans": [ + { + "bbox": [ + 318, + 243, + 535, + 324 + ], + "type": "table", + "html": "
Label\\( \\mathcal{L}_{\\text{limitation}} \\)\\( \\mathcal{S}^{3D} \\)\\( \\mathcal{L}_{\\text{adv}}^{3D} \\)FID (3D branch)
(A)30.6
(B)✓29.9
(C)✓✓9.29
(D)✓✓22.8
(E)✓✓✓5.14
", + "image_path": "dee20053f752579b4fe0f1f8ba85f9e0235e955d20e4c60971662284a3bbd56a.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 324, + 324, + 527, + 335 + ], + "lines": [ + { + "bbox": [ + 324, + 324, + 527, + 335 + ], + "spans": [ + { + "bbox": [ + 324, + 324, + 527, + 335 + ], + "type": "text", + "content": "Table 2. Ablation study on 3D-to-2D imitation strategy." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 309, + 351, + 365, + 412 + ], + "blocks": [ + { + "bbox": [ + 332, + 342, + 345, + 350 + ], + "lines": [ + { + "bbox": [ + 332, + 342, + 345, + 350 + ], + "spans": [ + { + "bbox": [ + 332, + 342, + 345, + 350 + ], + "type": "text", + "content": "(A)" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 309, + 351, + 365, + 412 + ], + "lines": [ + { + "bbox": [ + 309, + 351, + 365, + 412 + ], + "spans": [ + { + "bbox": [ + 309, + 351, + 365, + 412 + ], + "type": "image", + "image_path": "833fae670dccd3ebb76eefcbee3025926eb4faddbdc58f5eddd41c0b1f80d2ac.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 367, + 351, + 422, + 412 + ], + "blocks": [ + { + "bbox": [ + 392, + 342, + 403, + 350 + ], + "lines": [ + { + "bbox": [ + 392, + 342, + 403, + 350 + ], + "spans": [ + { + "bbox": [ + 392, + 342, + 403, + 350 + ], + "type": "text", + "content": "(C)" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 367, + 351, + 422, + 412 + ], + "lines": [ + { + "bbox": [ + 367, + 351, + 422, + 412 + ], + "spans": [ + { + "bbox": [ + 367, + 351, + 422, + 412 + ], + "type": "image", + "image_path": "22218623e84f17997f010abacc636b037bbe76e13a23dfac5d225c7a5bb07638.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 428, + 351, + 486, + 412 + ], + "blocks": [ + { + "bbox": [ + 451, + 342, + 462, + 350 + ], + "lines": [ + { + "bbox": [ + 451, + 342, + 462, + 350 + ], + "spans": [ + { + "bbox": [ + 451, + 342, + 462, + 350 + ], + "type": "text", + "content": "(D)" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 428, + 351, + 486, + 412 + ], + "lines": [ + { + "bbox": [ + 428, + 351, + 486, + 412 + ], + "spans": [ + { + "bbox": [ + 428, + 351, + 486, + 412 + ], + "type": "image", + "image_path": "09da423f0ddfe8a015fd99b3a0ec024205f7d1affa1101add44a0ad2d48cdacd.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 306, + 415, + 544, + 436 + ], + "lines": [ + { + "bbox": [ + 306, + 415, + 544, + 436 + ], + "spans": [ + { + "bbox": [ + 306, + 415, + 544, + 436 + ], + "type": "text", + "content": "Figure 7. Generated images under different learning strategies. The labels are consistent with Tab. 2." + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_caption" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 487, + 351, + 542, + 412 + ], + "blocks": [ + { + "bbox": [ + 510, + 342, + 521, + 350 + ], + "lines": [ + { + "bbox": [ + 510, + 342, + 521, + 350 + ], + "spans": [ + { + "bbox": [ + 510, + 342, + 521, + 350 + ], + "type": "text", + "content": "(E)" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 487, + 351, + 542, + 412 + ], + "lines": [ + { + "bbox": [ + 487, + 351, + 542, + 412 + ], + "spans": [ + { + "bbox": [ + 487, + 351, + 542, + 412 + ], + "type": "image", + "image_path": "b4abef14d9aba9aff194d61950270337fb308c6faf33754ceb152a52bd24a6f0.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 450, + 544, + 474 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 450, + 544, + 474 + ], + "spans": [ + { + "bbox": [ + 305, + 450, + 544, + 474 + ], + "type": "text", + "content": "plane generator. For efficiency, all experiments are conducted on FFHQ dataset at " + }, + { + "bbox": [ + 305, + 450, + 544, + 474 + ], + "type": "inline_equation", + "content": "256^{2}" + }, + { + "bbox": [ + 305, + 450, + 544, + 474 + ], + "type": "text", + "content": " resolution." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 486, + 546, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 486, + 546, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 486, + 546, + 713 + ], + "type": "text", + "content": "3D-to-2D imitation strategy. As shown in Tab. 2 and Fig. 7, We start from a generator without using the 3D-to-2D imitation and the 3D super-resolution module " + }, + { + "bbox": [ + 304, + 486, + 546, + 713 + ], + "type": "inline_equation", + "content": "S^{3D}" + }, + { + "bbox": [ + 304, + 486, + 546, + 713 + ], + "type": "text", + "content": " (setting A), by directly rendering the coarse tri-planes " + }, + { + "bbox": [ + 304, + 486, + 546, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{P}^c" + }, + { + "bbox": [ + 304, + 486, + 546, + 713 + ], + "type": "text", + "content": " for image synthesis. The rendered images in this way are blurry and lack fine details, leading to a high FID score of 30.6. Naively introducing the imitation loss (setting B) to improve the rendered images of " + }, + { + "bbox": [ + 304, + 486, + 546, + 713 + ], + "type": "inline_equation", + "content": "\\mathbf{P}^c" + }, + { + "bbox": [ + 304, + 486, + 546, + 713 + ], + "type": "text", + "content": " has minor influence, as the capacity of the coarse tri-planes are limited. Further incorporating the 3D super-resolution module (setting C) effectively releases the potential of the imitation loss and largely improves the image generation quality in terms of FID. However, the rendered images still lack rich details limited by the 3D-inconsistent 2D branch supervisions. Then, if the imitation loss is replaced with the adversarial loss (setting D), the image quality decreases significantly. This is due to that we only render small image patches to compute the corresponding losses for memory consideration. Under this circumstance, the adversarial loss is less" + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2344" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 49, + 70, + 286, + 127 + ], + "blocks": [ + { + "bbox": [ + 49, + 70, + 286, + 127 + ], + "lines": [ + { + "bbox": [ + 49, + 70, + 286, + 127 + ], + "spans": [ + { + "bbox": [ + 49, + 70, + 286, + 127 + ], + "type": "table", + "html": "
MethodFID (2D)FID (3D)#ParamMem.
w/o 3D-aware4.806.7129.0M2.3G
3D-aware latentOOMOOM111.7M11.6G
3D-aware tri-plane4.14-32.6M2.4G
3D-aware stream (Ours)3.915.1432.6M2.4G
", + "image_path": "c91a1f654816878646fd5bec7ce55be8e05debe381d5ff69d035d984c7a19aa5.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + }, + { + "bbox": [ + 47, + 127, + 286, + 171 + ], + "lines": [ + { + "bbox": [ + 47, + 127, + 286, + 171 + ], + "spans": [ + { + "bbox": [ + 47, + 127, + 286, + 171 + ], + "type": "text", + "content": "Table 3. Ablation study on designs of 3D-aware tri-plane generator. The FID scores are from 2D or 3D branch; #Param only considers the tri-plane generator " + }, + { + "bbox": [ + 47, + 127, + 286, + 171 + ], + "type": "inline_equation", + "content": "\\mathcal{E}" + }, + { + "bbox": [ + 47, + 127, + 286, + 171 + ], + "type": "text", + "content": " and Mem. indicates the GPU memory cost for generating the coarse tri-planes." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_footnote" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 49, + 179, + 286, + 423 + ], + "blocks": [ + { + "bbox": [ + 49, + 179, + 286, + 423 + ], + "lines": [ + { + "bbox": [ + 49, + 179, + 286, + 423 + ], + "spans": [ + { + "bbox": [ + 49, + 179, + 286, + 423 + ], + "type": "image", + "image_path": "96d7879c2b5af697e46cfa36f3d6f9753a24cc864d5707dbfb524698677d7a7e.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 427, + 286, + 437 + ], + "lines": [ + { + "bbox": [ + 47, + 427, + 286, + 437 + ], + "spans": [ + { + "bbox": [ + 47, + 427, + 286, + 437 + ], + "type": "text", + "content": "Figure 8. Generated tri-planes with or w/o 3D-aware convolutions." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 454, + 287, + 550 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 454, + 287, + 550 + ], + "spans": [ + { + "bbox": [ + 46, + 454, + 287, + 550 + ], + "type": "text", + "content": "stable compared to the imitation loss which is a perceptual-level reconstruction loss. This reveals the advantage of our imitation strategy, which could be extended to higher resolution via patch-wise optimization while maintaining a good image generation quality. Finally, leveraging all the three components (setting E) yields the best result, where the imitation loss keeps the overall structure reasonable and the adversarial loss helps with fine details learning." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 557, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 557, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 557, + 288, + 713 + ], + "type": "text", + "content": "3D-aware tri-plane generator. Table 3 shows the ablation study on the 3D-aware tri-plane generator. We compare our design with two alternatives and one without 3D-aware convolutions originally adopted by EG3D. We report the parameter size of the tri-plane generators, the inference memory cost to generate the coarse tri-planes, as well as the final image generation quality in terms of FID. In the first alternative, we remove our 3D-aware stream, and leverage 3D-aware convolutions for the latent feature maps in the main stream, namely 3D-aware latent. Since the main stream feature maps have relatively larger feature channels, and the 3D-aware convolution requires to concatenate two additional tensors with the same size as the input tensor, this" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 72, + 545, + 275 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 275 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 275 + ], + "type": "text", + "content": "design increases the parameter size and memory consumption significantly, and raises the out-of-memory issue during training. In the second alternative, namely 3D-aware tri-plane, we directly apply 3D-aware convolutions in the output stream, by inserting them after the upsampling operations at each resolution, instead of using the additional 3D-aware stream. This strategy leads to an improvement of the image generation quality of the 2D branch, and largely reduces the parameter size and memory cost compare to the first design. Finally, our 3D-aware stream design further improves the image generation quality without introducing extra parameters and memory costs. Therefore, we adopt it as our final 3D-aware tri-plane generator for 3D-to-2D imitation. It effectively lowers the FID score of both the 2D and 3D branches compared to the original structure without 3D-aware convolutions, with only a minor increase of the parameter size and memory cost." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 275, + 545, + 383 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 275, + 545, + 383 + ], + "spans": [ + { + "bbox": [ + 304, + 275, + 545, + 383 + ], + "type": "text", + "content": "Figure 8 further shows the synthesized tri-planes, where we visualize the L2 norm of each spatial location on the three orthogonal planes. Our method leveraging the 3D-aware stream produces more informative tri-planes. The generated planes of the side-views better depict the characters of different instances (e.g., see the difference of the profiles on the " + }, + { + "bbox": [ + 304, + 275, + 545, + 383 + ], + "type": "inline_equation", + "content": "yz" + }, + { + "bbox": [ + 304, + 275, + 545, + 383 + ], + "type": "text", + "content": " planes). Our frontal planes (i.e. " + }, + { + "bbox": [ + 304, + 275, + 545, + 383 + ], + "type": "inline_equation", + "content": "xy" + }, + { + "bbox": [ + 304, + 275, + 545, + 383 + ], + "type": "text", + "content": " planes) also demonstrate more clear head silhouettes compared to those without using the 3D-aware convolutions." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 394, + 383, + 406 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 394, + 383, + 406 + ], + "spans": [ + { + "bbox": [ + 306, + 394, + 383, + 406 + ], + "type": "text", + "content": "5. Conclusions" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 414, + 545, + 534 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 414, + 545, + 534 + ], + "spans": [ + { + "bbox": [ + 304, + 414, + 545, + 534 + ], + "type": "text", + "content": "We presented a novel learning strategy for 3D-aware GANs to achieve image synthesis of high quality and strict 3D consistency. The core idea is to enforce the images synthesized by the generator's 3D rendering branch to mimic those generated by its 2D super-resolution branch. We also introduced 3D-aware convolutions to the generator to further improve the image generation quality. With the above strategies, our method largely improves the image quality among methods using direct 3D rendering, which we believe enables a new way for more realistic 3D generation." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 540, + 545, + 659 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 540, + 545, + 659 + ], + "spans": [ + { + "bbox": [ + 304, + 540, + 545, + 659 + ], + "type": "text", + "content": "Limitation and future works. Our method has several limitations. The image generation quality of its 3D branch still lags behind that of the 2D branch. Certain generated 3D structures such as hairs and cat whiskers are stuck to the geometry surfaces instead of correctly floating in the volumetric space. The 3D-to-2D imitation strategy also introduces extra training time and memory costs compared to only learning the 2D branch. We expect more effective learning strategies and more advanced 3D representations to alleviate these problems." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "Ethics consideration. The goal of this paper is to generate images of virtual subjects. It is not intended for creating misleading or deceptive contents of real people and we do not condone any such harmful behavior." + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2345" + } + ] + } + ], + "index": 12 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "type": "text", + "content": "[1] Robert C Bolles, H Harlyn Baker, and David H Marimont. Epipolar-plane image analysis: An approach to determining structure from motion. International journal of computer vision, 1(1):7-55, 1987. 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 137, + 288, + 181 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 137, + 288, + 181 + ], + "spans": [ + { + "bbox": [ + 53, + 137, + 288, + 181 + ], + "type": "text", + "content": "[2] Andrew Brock, Jeff Donahue, and Karen Simonyan. Large scale GAN training for high fidelity natural image synthesis. In Proceedings of the International Conference on Learning Representations, 2019. 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 182, + 288, + 249 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 182, + 288, + 249 + ], + "spans": [ + { + "bbox": [ + 53, + 182, + 288, + 249 + ], + "type": "text", + "content": "[3] Eric R Chan, Connor Z Lin, Matthew A Chan, Koki Nagano, Boxiao Pan, Shalini De Mello, Orazio Gallo, Leonidas Guibas, Jonathan Tremblay, Sameh Khamis, et al. Efficient geometry-aware 3D generative adversarial networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1, 2, 3, 4, 6, 7" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 250, + 288, + 305 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 250, + 288, + 305 + ], + "spans": [ + { + "bbox": [ + 53, + 250, + 288, + 305 + ], + "type": "text", + "content": "[4] Eric R Chan, Marco Monteiro, Petr Kellnhofer, Jiajun Wu, and Gordon Wetzstein. pi-GAN: Periodic implicit generative adversarial networks for 3D-aware image synthesis. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. 1, 2, 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 307, + 287, + 351 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 307, + 287, + 351 + ], + "spans": [ + { + "bbox": [ + 53, + 307, + 287, + 351 + ], + "type": "text", + "content": "[5] Yunjey Choi, Youngjung Uh, Jaejun Yoo, and Jung-Woo Ha. StarGAN v2: Diverse image synthesis for multiple domains. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, 2020. 2, 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 352, + 288, + 396 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 352, + 288, + 396 + ], + "spans": [ + { + "bbox": [ + 53, + 352, + 288, + 396 + ], + "type": "text", + "content": "[6] Yu Deng, Jiaolong Yang, Jianfeng Xiang, and Xin Tong. GRAM: Generative radiance manifolds for 3D-aware image generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 1, 2, 3, 6, 7" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 397, + 288, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 397, + 288, + 453 + ], + "spans": [ + { + "bbox": [ + 53, + 397, + 288, + 453 + ], + "type": "text", + "content": "[7] Terrance DeVries, Miguel Angel Bautista, Nitish Srivastava, Graham W Taylor, and Joshua M Susskind. Unconstrained scene generation with locally conditioned radiance fields. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2021. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 454, + 288, + 509 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 454, + 288, + 509 + ], + "spans": [ + { + "bbox": [ + 53, + 454, + 288, + 509 + ], + "type": "text", + "content": "[8] Ian Goodfellow, Jean Pouget-Abadie, Mehdi Mirza, Bing Xu, David Warde-Farley, Sherjil Ozair, Aaron Courville, and Yoshua Bengio. Generative adversarial nets. In Proceedings of the Advances in Neural Information Processing Systems, 2014. 1, 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 510, + 287, + 564 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 510, + 287, + 564 + ], + "spans": [ + { + "bbox": [ + 53, + 510, + 287, + 564 + ], + "type": "text", + "content": "[9] Jiatao Gu, Lingjie Liu, Peng Wang, and Christian Theobalt. StyleNeRF: A style-based 3D aware generator for high-resolution image synthesis. In Proceedings of the International Conference on Learning Representations, 2022. 1, 2, 3, 6, 7" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 567, + 287, + 612 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 567, + 287, + 612 + ], + "spans": [ + { + "bbox": [ + 48, + 567, + 287, + 612 + ], + "type": "text", + "content": "[10] Erik Härkönen, Aaron Hertzmann, Jaakko Lehtinen, and Sylvain Paris. GANSpace: Discovering interpretable GAN controls. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 613, + 287, + 656 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 613, + 287, + 656 + ], + "spans": [ + { + "bbox": [ + 48, + 613, + 287, + 656 + ], + "type": "text", + "content": "[11] Philipp Henzler, Niloy J Mitra, and Tobias Ritschel. Escaping plato's cave: 3D shape from adversarial rendering. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2019. 2, 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 658, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 658, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 658, + 287, + 713 + ], + "type": "text", + "content": "[12] Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. GANs trained by a two time-scale update rule converge to a local nash equilibrium. In Proceedings of the Advances in Neural Information Processing Systems, 2017. 2, 7" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 307, + 73, + 547, + 116 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 547, + 116 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 547, + 116 + ], + "type": "text", + "content": "[13] Ali Jahanian, Lucy Chai, and Phillip Isola. On the \"steerability\" of generative adversarial networks. In Proceedings of the International Conference on Learning Representations, 2020. 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 118, + 545, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 118, + 545, + 139 + ], + "spans": [ + { + "bbox": [ + 307, + 118, + 545, + 139 + ], + "type": "text", + "content": "[14] James T Kajiya and Brian P Von Herzen. Ray tracing volume densities. ACM SIGGRAPH, 18(3):165-174, 1984. 1, 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 308, + 140, + 545, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 140, + 545, + 194 + ], + "spans": [ + { + "bbox": [ + 308, + 140, + 545, + 194 + ], + "type": "text", + "content": "[15] Tero Karras, Miika Aittala, Janne Hellsten, Samuli Laine, Jaakko Lehtinen, and Timo Aila. Training generative adversarial networks with limited data. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 6" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 195, + 545, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 195, + 545, + 239 + ], + "spans": [ + { + "bbox": [ + 308, + 195, + 545, + 239 + ], + "type": "text", + "content": "[16] Tero Karras, Miika Aittala, Samuli Laine, Erik Härkönen, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Alias-free generative adversarial networks. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 1" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 239, + 545, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 239, + 545, + 293 + ], + "spans": [ + { + "bbox": [ + 308, + 239, + 545, + 293 + ], + "type": "text", + "content": "[17] Tero Karras, Samuli Laine, and Timo Aila. A style-based generator architecture for generative adversarial networks. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 4401-4410, 2019. 2, 3, 6" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 293, + 547, + 348 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 293, + 547, + 348 + ], + "spans": [ + { + "bbox": [ + 308, + 293, + 547, + 348 + ], + "type": "text", + "content": "[18] Tero Karras, Samuli Laine, Miika Aittala, Janne Hellsten, Jaakko Lehtinen, and Timo Aila. Analyzing and improving the image quality of styleGAN. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. 1, 3, 5" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 349, + 545, + 392 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 349, + 545, + 392 + ], + "spans": [ + { + "bbox": [ + 308, + 349, + 545, + 392 + ], + "type": "text", + "content": "[19] Chen-Hsuan Lin, Jun Gao, Luming Tang, Towaki Takikawa, Xiaohui Zeng, Xun Huang, Karsten Kreis, Sanja Fidler, Ming-Yu Liu, and Tsung-Yi Lin. Magic3D: High-resolution text-to-3D content creation. arXiv:2211.10440, 2022. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 393, + 545, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 393, + 545, + 426 + ], + "spans": [ + { + "bbox": [ + 308, + 393, + 545, + 426 + ], + "type": "text", + "content": "[20] William E Lorensen and Harvey E Cline. Marching cubes: A high resolution 3D surface construction algorithm. ACM SIGGRAPH, 21(4):163-169, 1987. 6" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 426, + 545, + 470 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 426, + 545, + 470 + ], + "spans": [ + { + "bbox": [ + 308, + 426, + 545, + 470 + ], + "type": "text", + "content": "[21] Lars Mescheder, Andreas Geiger, and Sebastian Nowozin. Which training methods for GANs do actually converge? In Proceedings of the International Conference on Machine Learning, 2018. 4" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 471, + 545, + 525 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 471, + 545, + 525 + ], + "spans": [ + { + "bbox": [ + 308, + 471, + 545, + 525 + ], + "type": "text", + "content": "[22] Lars Mescheder, Michael Oechsle, Michael Niemeyer, Sebastian Nowozin, and Andreas Geiger. Occupancy networks: Learning 3D reconstruction in function space. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 525, + 545, + 581 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 525, + 545, + 581 + ], + "spans": [ + { + "bbox": [ + 308, + 525, + 545, + 581 + ], + "type": "text", + "content": "[23] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. In Proceedings of the European Conference on Computer Vision, 2020. 1, 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 582, + 545, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 582, + 545, + 635 + ], + "spans": [ + { + "bbox": [ + 308, + 582, + 545, + 635 + ], + "type": "text", + "content": "[24] Thu Nguyen-Phuoc, Chuan Li, Lucas Theis, Christian Richardt, and Yong-Liang Yang. Hologan: Unsupervised learning of 3D representations from natural images. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 7588-7597, 2019. 2, 3" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 636, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 636, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 308, + 636, + 545, + 689 + ], + "type": "text", + "content": "[25] Michael Niemeyer and Andreas Geiger. Giraffe: Representing scenes as compositional generative neural feature fields. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 11453-11464, 2021. 1, 2, 3" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 691, + 545, + 713 + ], + "type": "text", + "content": "[26] Michael Oechsle, Songyou Peng, and Andreas Geiger. Unisurf: Unifying neural implicit surfaces and radiance" + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 316, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 316, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 316, + 757 + ], + "type": "text", + "content": "2346" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 288, + 714 + ], + "type": "list", + "angle": 0, + "index": 13, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 105 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 105 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 105 + ], + "type": "text", + "content": "fields for multi-view reconstruction. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2021. 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 287, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 287, + 162 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 287, + 162 + ], + "type": "text", + "content": "[27] Roy Or-El, Xuan Luo, Mengyi Shan, Eli Shechtman, Jeong Joon Park, and Ira Kemelmacher-Shlizerman. StyleSDF: High-resolution 3D-consistent image and geometry generation. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2022. 1, 3, 6, 7" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 163, + 288, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 163, + 288, + 217 + ], + "spans": [ + { + "bbox": [ + 48, + 163, + 288, + 217 + ], + "type": "text", + "content": "[28] Xingang Pan, Bo Dai, Ziwei Liu, Chen Change Loy, and Ping Luo. Do 2D GANs know 3D shape? unsupervised 3D shape reconstruction from 2d image gans. In Proceedings of the International Conference on Learning Representations, 2021. 2, 3" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 220, + 287, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 220, + 287, + 262 + ], + "spans": [ + { + "bbox": [ + 48, + 220, + 287, + 262 + ], + "type": "text", + "content": "[29] Xingang Pan, Ayush Tewari, Lingjie Liu, and Christian Theobalt. Gan2x: Non-lambertian inverse rendering of image gans. In Proceedings of the International Conference on 3D Vision, 2022. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 264, + 287, + 319 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 264, + 287, + 319 + ], + "spans": [ + { + "bbox": [ + 48, + 264, + 287, + 319 + ], + "type": "text", + "content": "[30] Xingang Pan, Xudong Xu, Chen Change Loy, Christian Theobalt, and Bo Dai. A shading-guided generative implicit model for shape-accurate 3D-aware image synthesis. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 320, + 287, + 376 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 320, + 287, + 376 + ], + "spans": [ + { + "bbox": [ + 48, + 320, + 287, + 376 + ], + "type": "text", + "content": "[31] Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. DeepSDF: Learning continuous signed distance functions for shape representation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2019. 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 376, + 287, + 409 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 376, + 287, + 409 + ], + "spans": [ + { + "bbox": [ + 48, + 376, + 287, + 409 + ], + "type": "text", + "content": "[32] Ben Poole, Ajay Jain, Jonathan T Barron, and Ben Mildenhall. Dreamfusion: Text-to-3D using 2D diffusion. arXiv:2209.14988, 2022. 2, 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 411, + 288, + 465 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 411, + 288, + 465 + ], + "spans": [ + { + "bbox": [ + 48, + 411, + 288, + 465 + ], + "type": "text", + "content": "[33] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. High-resolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 467, + 287, + 542 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 467, + 287, + 542 + ], + "spans": [ + { + "bbox": [ + 48, + 467, + 287, + 542 + ], + "type": "text", + "content": "[34] Chitwan Sahara, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily Denton, Seyed Kamyar Seyed Ghasemipour, Raphael Gontijo-Lopes, Burcu Karagol Ayan, Tim Salimans, et al. Photorealistic text-to-image diffusion models with deep language understanding. In Proceedings of the Advances in Neural Information Processing Systems, 2022. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 544, + 287, + 588 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 544, + 287, + 588 + ], + "spans": [ + { + "bbox": [ + 48, + 544, + 287, + 588 + ], + "type": "text", + "content": "[35] Katja Schwarz, Yiyi Liao, Michael Niemeyer, and Andreas Geiger. GRAF: Generative radiance fields for 3D-aware image synthesis. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 1, 2, 3, 5" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 590, + 287, + 643 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 590, + 287, + 643 + ], + "spans": [ + { + "bbox": [ + 48, + 590, + 287, + 643 + ], + "type": "text", + "content": "[36] Katja Schwarz, Axel Sauer, Michael Niemeyer, Yiyi Liao, and Andreas Geiger. VoxGRAF: Fast 3D-aware image synthesis with sparse voxel grids. In Proceedings of the Advances in Neural Information Processing Systems, 2022. 1, 3, 6, 7" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 646, + 287, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 646, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 48, + 646, + 287, + 689 + ], + "type": "text", + "content": "[37] Yujun Shen, Jinjin Gu, Xiaou Tang, and Bolei Zhou. Interpreting the latent space of GANs for semantic face editing. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2020. 3" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 48, + 691, + 287, + 714 + ], + "type": "text", + "content": "[38] Yichun Shi, Divyansh Aggarwal, and Anil K Jain. Lifting 2D StyleGAN for 3D-aware face generation. In Proceedings of" + } + ] + } + ], + "index": 12 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 27, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "text", + "content": "the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2021. 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 307, + 96, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 96, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 96, + 545, + 150 + ], + "type": "text", + "content": "[39] Vincent Sitzmann, Julien Martel, Alexander Bergman, David Lindell, and Gordon Wetzstein. Implicit neural representations with periodic activation functions. In Proceedings of the Advances in Neural Information Processing Systems, 2020. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 152, + 545, + 206 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 206 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 206 + ], + "type": "text", + "content": "[40] Vincent Sitzmann, Michael Zollhöfer, and Gordon Wetzstein. Scene representation networks: continuous 3D-structure-aware neural scene representations. In Proceedings of the Advances in Neural Information Processing Systems, 2019. 3" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 209, + 545, + 252 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 209, + 545, + 252 + ], + "spans": [ + { + "bbox": [ + 307, + 209, + 545, + 252 + ], + "type": "text", + "content": "[41] Ivan Skorokhodov, Sergey Tulyakov, Yiqun Wang, and Peter Wonka. EpiGRAF: Rethinking training of 3D GANs. In Proceedings of the Advances in Neural Information Processing Systems, 2022. 1, 2, 3, 5, 6, 7" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 254, + 545, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 254, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 307, + 254, + 545, + 285 + ], + "type": "text", + "content": "[42] Attila Szabó, Givi Meishvili, and Paolo Favaro. Unsupervised generative 3D shape learning from natural images. arXiv:1910.00287, 2019. 3" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 288, + 545, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 288, + 545, + 342 + ], + "spans": [ + { + "bbox": [ + 308, + 288, + 545, + 342 + ], + "type": "text", + "content": "[43] Peng Wang, Lingjie Liu, Yuan Liu, Christian Theobalt, Taku Komura, and Wenping Wang. NeuS: Learning neural implicit surfaces by volume rendering for multi-view reconstruction. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 1, 3, 7" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 344, + 545, + 409 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 344, + 545, + 409 + ], + "spans": [ + { + "bbox": [ + 308, + 344, + 545, + 409 + ], + "type": "text", + "content": "[44] Tengfei Wang, Bo Zhang, Ting Zhang, Shuyang Gu, Jianmin Bao, Tadas Baltrusaitis, Jingjing Shen, Dong Chen, Fang Wen, Qifeng Chen, et al. Rodin: A generative model for sculpting 3D digital avatars using diffusion. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition, 2023. 2, 3, 5" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 411, + 545, + 464 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 411, + 545, + 464 + ], + "spans": [ + { + "bbox": [ + 308, + 411, + 545, + 464 + ], + "type": "text", + "content": "[45] Jianfeng Xiang, Jiaolong Yang, Yu Deng, and Xin Tong. GRAM-HD: 3D-consistent image generation at high resolution with generative radiance manifolds. In Proceedings of the IEEE/CVF International Conference on Computer Vision, 2023. 1, 3, 6, 7" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 467, + 545, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 467, + 545, + 510 + ], + "spans": [ + { + "bbox": [ + 308, + 467, + 545, + 510 + ], + "type": "text", + "content": "[46] Xudong Xu, Xingang Pan, Dahua Lin, and Bo Dai. Generative occupancy fields for 3D surface-aware image synthesis. In Proceedings of the Advances in Neural Information Processing Systems, 2021. 3" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 512, + 545, + 567 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 512, + 545, + 567 + ], + "spans": [ + { + "bbox": [ + 308, + 512, + 545, + 567 + ], + "type": "text", + "content": "[47] Yinghao Xu, Sida Peng, Ceyuan Yang, Yujun Shen, and Bolei Zhou. 3D-aware image synthesis via learning structural and textural representations. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18430-18439, 2022. 3, 6, 7" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 568, + 545, + 622 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 568, + 545, + 622 + ], + "spans": [ + { + "bbox": [ + 308, + 568, + 545, + 622 + ], + "type": "text", + "content": "[48] Yang Xue, Yuheng Li, Krishna Kumar Singh, and Yong Jae Lee. Giraffe HD: A high-resolution 3D-aware generative model. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 18440-18449, 2022. 1, 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 624, + 545, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 624, + 545, + 678 + ], + "spans": [ + { + "bbox": [ + 308, + 624, + 545, + 678 + ], + "type": "text", + "content": "[49] Richard Zhang, Phillip Isola, Alexei A Efros, Eli Shechtman, and Oliver Wang. The unreasonable effectiveness of deep features as a perceptual metric. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2018. 2, 4" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 680, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 680, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 680, + 545, + 713 + ], + "type": "text", + "content": "[50] Xuanmeng Zhang, Zhedong Zheng, Daiheng Gao, Bang Zhang, Pan Pan, and Yi Yang. Multi-view consistent generative adversarial networks for 3D-aware image synthesis." + } + ] + } + ], + "index": 26 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "2347" + } + ] + } + ], + "index": 28 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 251 + ], + "type": "list", + "angle": 0, + "index": 4, + "blocks": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 287, + 95 + ], + "type": "text", + "content": "In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, 2022. 2" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 159 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 159 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 159 + ], + "type": "text", + "content": "[51] Yuxuan Zhang, Wenzheng Chen, Huan Ling, Jun Gao, Yi-nan Zhang, Antonio Torralba, and Sanja Fidler. Image gans meet differentiable rendering for inverse graphics and interpretable 3D neural rendering. In Proceedings of the International Conference on Learning Representations, 2021. 2, 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 163, + 287, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 163, + 287, + 217 + ], + "spans": [ + { + "bbox": [ + 48, + 163, + 287, + 217 + ], + "type": "text", + "content": "[52] Xiaoming Zhao, Fangchang Ma, David Guera, Zhile Ren, Alexander G Schwing, and Alex Colburn. Generative multiplane images: Making a 2D GAN 3D-aware. In Proceedings of the European Conference on Computer Vision, 2022. 1, 2, 3, 6, 7" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 219, + 287, + 251 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 219, + 287, + 251 + ], + "spans": [ + { + "bbox": [ + 48, + 219, + 287, + 251 + ], + "type": "text", + "content": "[53] Peng Zhou, Lingxi Xie, Bingbing Ni, and Qi Tian. Cips-3d: A 3D-aware generator of gans based on conditionally-independent pixel synthesis. arXiv:2110.09788, 2021. 3" + } + ] + } + ], + "index": 3 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 749, + 315, + 757 + ], + "type": "text", + "content": "2348" + } + ] + } + ], + "index": 5 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 10 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/ea56ef7d-d0ee-4b4c-86bd-22698b72c0f8_content_list.json b/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/ea56ef7d-d0ee-4b4c-86bd-22698b72c0f8_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..1e806b00f8df688898961ac0f1b66d8c199c727d --- /dev/null +++ b/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/ea56ef7d-d0ee-4b4c-86bd-22698b72c0f8_content_list.json @@ -0,0 +1,1425 @@ +[ + { + "type": "text", + "text": "MiniROAD: Minimal RNN Framework for Online Action Detection", + "text_level": 1, + "bbox": [ + 142, + 130, + 826, + 150 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Joungbin An $^{1}$ Hyolim Kang $^{1}$ Su Ho Han $^{1}$ Ming-Hsuan Yang $^{1,2,3}$ Seon Joo Kim $^{1}$ $^{1}$ Yonsei University $^{2}$ UC Merced $^{3}$ Google Research", + "bbox": [ + 129, + 179, + 839, + 217 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 251, + 313, + 266 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Online Action Detection (OAD) is the task of identifying actions in streaming videos without access to future frames. Much effort has been devoted to effectively capturing long-range dependencies, with transformers receiving the spotlight for their ability to capture long-range temporal structures. In contrast, RNNs have received less attention lately, due to their lower performance compared to recent methods that utilize transformers. In this paper, we investigate the underlying reasons for the inferior performance of RNNs compared to transformer-based algorithms. Our findings indicate that the discrepancy between training and inference is the primary hindrance to the effective training of RNNs. To address this, we propose applying non-uniform weights to the loss computed at each time step, which allows the RNN model to learn from the predictions made in an environment that better resembles the inference stage. Extensive experiments on three benchmark datasets, THU-MOS, TVSeries, and FineAction demonstrate that a minimal RNN-based model trained with the proposed methodology performs equally or better than the existing best methods with a significant increase in efficiency. The code is available at https://github.com/jbistanbul/MiniROAD.", + "bbox": [ + 76, + 282, + 473, + 617 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 646, + 209, + 662 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Online Action Detection (OAD) is a challenging task that involves identifying actions taking place in a streaming video without access to future frames. Since its introduction [7], OAD has gained great attention in research circles, as it has numerous real-world applications, such as autonomous driving [20], smart surveillance systems [26, 27], and anomaly detection [31]. These applications require the ability to process streaming videos in real-time, making OAD an essential component of many advanced systems. As a result, there has been a growing interest in developing more accurate and efficient methods for performing OAD.", + "bbox": [ + 75, + 672, + 468, + 839 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "To address the challenges of OAD, recent efforts have focused on developing novel models for analyzing streaming videos in real-time. The conventional process of OAD consists of two stages. In the first stage, frames are con", + "bbox": [ + 75, + 839, + 470, + 901 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/4e46ec5a3f87f4a85b8ba9bc6e9b9c937b50a833faf5ba68ef3179f3e503bed4.jpg", + "image_caption": [ + "Figure 1: Performance of recent OAD methods with respect to GFLOPs and the model's size." + ], + "image_footnote": [], + "bbox": [ + 532, + 260, + 838, + 474 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "verted into a sequence of features by a feature extractor. In the second stage, the extracted features are processed to capture the temporal information required for performing OAD. Much attention on OAD research has been paid to this second stage where the two mainstream models are RNNs [11, 30, 18, 5] and Transformers [9, 10, 33].", + "bbox": [ + 496, + 532, + 893, + 625 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Each model has its strengths and weaknesses. RNNs can capture temporal transitions effectively by modeling sequences recurrently but are known for their training difficulties [23, 30]. Transformers can capture long-term dependencies through self-attention, however, attention computation is computationally expensive. Although recent research has shifted towards using Transformer models, our paper revisits RNN, which has been overlooked in recent studies.", + "bbox": [ + 496, + 626, + 893, + 760 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In this work, we show that RNN's intrinsic inductive bias—prioritizing the current input while preserving meaningful temporal information from the histories—makes them well-suited for OAD. Unlike in natural language processing, where a distant word can significantly affect the next sequence prediction, we observe that in OAD, the current and its neighboring frames have a dominant influence on the current prediction. In addition, RNN is efficient, as it requires a small computational overhead compared to", + "bbox": [ + 496, + 763, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "10341", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "the transformer models, making them well-suited for online tasks that require running in real-time.", + "bbox": [ + 76, + 90, + 468, + 121 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Despite its architecture being well-suited for the OAD task, RNN has been recently overlooked due to the promising results shown by transformer-based models. The prevailing reasoning behind the lower performance of RNN based method was the difficulty of learning long-range dependencies [37, 23]. In this paper, we find that it is the training-inference discrepancy that hinders the effective training of RNNs.", + "bbox": [ + 75, + 123, + 467, + 243 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "During inference, the video is processed frame-by-frame in a streaming fashion. During training, however, the video is divided into multiple clips, which are then fed to the model, as illustrated in Figure 2. This creates a significant discrepancy between the two phases since videos are usually much longer than the training clips. Consequently, the clips provide limited temporal information, leading to a restricted view of the video during training. This limitation is not as problematic for recent OAD models using transformers as it is for models using RNNs. This is because recent transformer models utilize the temporal information between clips using explicit long-term memory even during training. At the same time, RNNs do not since they receive a non-informative hidden state initialized as zero at the beginning of the clip. As a result, RNNs make most predictions during training with the hidden state that lacks temporal information, whereas it makes most predictions during inference with the hidden state accumulated with sufficient temporal information.", + "bbox": [ + 75, + 246, + 467, + 532 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "We demonstrate that addressing the training and inference discrepancy in RNNs alone can significantly improve their performance without requiring any changes to their architecture. Specifically, we find that introducing nonuniform weights to losses at different time steps can alleviate this discrepancy, which is a primary factor contributing to RNN's suboptimal performance. This approach differs from the conventional assumption of averaging the loss over the joint prediction, as we demonstrate that non-uniform weights to the loss are essential for effectively training the model. We demonstrate the effectiveness of our methodology using Minimal Recurrent neural network for Online Action Detection (MiniROAD), which is a lightweight GRU based model. Figure 1 shows the comparison of our model with other recent models in terms of the model's performance, GFLOPs, and size. It shows that our method with only $\\sim 0.4\\%$ computational power needed for the previous state-of-the-art, is able to achieve better performance.", + "bbox": [ + 75, + 535, + 467, + 821 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Our model is evaluated on conventional OAD benchmark datasets, including THUMOS'14 and TVSeries, as well as on the recently introduced FineAction dataset. As conventional datasets used for benchmarking OAD tasks are relatively small, the much larger FineAction dataset offers", + "bbox": [ + 75, + 824, + 467, + 898 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "a more challenging testbed that better depicts real-life scenarios. Larger datasets like FineAction open up more possibilities for future work on OAD and hence our results can serve as a strong baseline. Our experiments show that our proposed methodologies achieve on-par or better results on the benchmarked dataset with significant improvements in efficiency.", + "bbox": [ + 496, + 90, + 890, + 196 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The main contributions of this work are:", + "bbox": [ + 517, + 198, + 787, + 210 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We revisit the potential of RNNs and identify the training-inference discrepancy as a primary cause of their lower performance. To address this issue, we propose a simple yet effective method that makes RNN both effective and efficient in capturing the essential temporal information for online action detection.", + "- Extensive experimental results show that the proposed method performs favorably against the state-of-the-art with high efficiency; our model with only $\\sim 0.4\\%$ computational overhead compared to the existing methods, achieves on par or better performance on a challenging benchmark dataset, with $\\sim 17\\%$ performance improvement over the state-of-the-art in a large-scale dataset.", + "- We expand our methodology and carry out performance evaluation on Action Anticipation and show the applicability of our method on other online tasks." + ], + "bbox": [ + 517, + 214, + 890, + 470 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 487, + 640, + 502 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Online Action Detection", + "text_level": 1, + "bbox": [ + 500, + 512, + 720, + 527 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The Online Action Detection task [7] involves detecting actions in the current frame online, using information from the past up to the present. Earlier approaches to Online Action Detection relied on recurrent models. Geest et al. propose a two-stream feedback network [8], utilizing LSTM [18] where one stream focuses on feature representation and the other on temporal patterns. RED [14] takes advantage of reinforcement learning to make action predictions as early as possible. Recent works using RNNs focus on designing more effective RNN cells. TRN [39] models a greater temporal context by having the LSTM cell [18] anticipate the future. IDN [12] uses the GRU cell [4] to explicitly differentiate relevant information for ongoing actions. In [21], FATSnet employs GRU to perform future anticipation and temporal smoothing for more effective current prediction. On the other hand, WOAD [15] introduces a method for weakly supervised online action detection. Existing RNN-based models mainly concentrate on developing more powerful RNN architectures to handle the task.", + "bbox": [ + 496, + 537, + 890, + 823 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Transformers have also been used for the OAD task. OadTR [36] introduces a transformer encoder-decoder architecture for capturing long-term relations through self-attention. In [40], LSTR achieves significant performance improvements by employing a two-stage memory compres", + "bbox": [ + 496, + 825, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "10342", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/4d0ae3b1f4473b1a80ada65e4806ee0f0cf3396eb661b01f31bac37af0b86b4f.jpg", + "image_caption": [ + "Figure 2: Illustration of Training and Inference Discrepancy. During the inference stage (top), frames are fed to the model sequentially in a streaming fashion. The hidden state evolves across the entire video, progressively incorporating accumulated temporal context (depicted as darkening over time). In the training stage (bottom), the video is divided into shorter clips of length $L$ , serving as model inputs. Here, the model solely relies on temporal information within each clip, lacking inter-clip associations. This yields dominant predictions constrained by clip-specific information." + ], + "image_footnote": [], + "bbox": [ + 133, + 85, + 843, + 284 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "sion design with transformers, allowing for capturing long-term temporal and short-term context through self-attention. This two-stage memory design has been further advanced in subsequent works. GateHUB [3] improves the two-stage architecture with a Gated History Unit to address the limitations of prior cross-attention methods. This avoids incorrect current frame predictions by appropriately weighting informative and uninformative frames. Recently, TeSTra [43] extends the LSTR architecture by introducing two temporal smoothing kernels to reduce inference computation cost.", + "bbox": [ + 75, + 387, + 472, + 537 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Although these transformer models have achieved state-of-the-art results, the attention computation involved in encoding long-term and short-term memory is computationally expensive. In this work, we show that RNNs, without modifying the internals of the architecture, can be just as effective in processing streaming videos with the proposed methodology alone.", + "bbox": [ + 75, + 541, + 470, + 647 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Sequence Modeling", + "text_level": 1, + "bbox": [ + 76, + 662, + 264, + 680 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "As many real-world applications involve processing time-series data, sequential modeling has been a topic of ongoing research. Recurrent Neural Networks (RNNs) are one of the most commonly used models for sequence modeling, with popular variants including [18] and [5]. These variants introduce mechanisms within the RNN cell to improve its memory capacity while attending to important parts of the sequential data. 1D CNNs [22] incorporate convolution operations to capture the temporal structure of time-series data. Recent advances have been made using transformers [33] that incorporate attention mechanisms for capturing short and long-term dependencies. Ever since its success in the language domain, its use has been widespread in various fields [10, 9, 1, 38].", + "bbox": [ + 75, + 689, + 472, + 901 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "There have been ongoing efforts on exploring non-transformer architectures. Gu et al. [16] introduces the State Space Model (SSM) in tackling sequence data, proving its efficacy in effectively handling long sequences. A recent work [25] demonstrates that RNNs can match the performance and training speed of SSMs by applying techniques such as linearizing and diagonalizing the recurrence, along with better parameterizations and initializations. Recently, there has been a notable surge in interest surrounding a novel variant of RNN called RWKV [28]. This architecture is the first non-transformer model to be successfully scaled to tens of billions of parameters, bringing together the efficient parallelizable training of transformers with the inference efficiency of RNNs. Our research aligns with these works in resurrecting RNNs in the transformer era.", + "bbox": [ + 496, + 387, + 893, + 614 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Methodology", + "text_level": 1, + "bbox": [ + 500, + 654, + 635, + 672 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Provided a live streaming video, our objective is to recognize actions in the current frame based on past observations up to the current time. Since $v_{1}^{t}$ , a streaming video from the start until the current time $t$ only provides observations $\\{v_{1},\\dots,v_{t}\\}$ for the past $t$ frames, it is not possible to access any information beyond $v_{t}$ . In this setting, the task is to use $v_{1}^{t}$ to predict $\\hat{y}_t \\in \\{0,1,\\dots,K\\}$ where $K$ is the number of action classes and index 0 is the background class. During training, the video is divided into clips, each of length $L$ , and hence clips of $v_{t - L}^{t}$ are given as input. Following the convention, we suppose that a pre-trained feature extractor is available which can convert each frame $v_{t}$ into a feature vector $f_{t} \\in \\mathbb{R}^{C}$ . Our method employs the feature vector $f_{t}$ as the input at current time $t$ to predict $\\hat{y}_t$ .", + "bbox": [ + 496, + 689, + 893, + 902 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "10343", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Overview", + "text_level": 1, + "bbox": [ + 76, + 90, + 187, + 104 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Our method is developed based on the observation that a discrepancy exists between the training and the inference stages, which hinders the effective training of sequence-to-sequence models. Figure 2 illustrates this training-inference discrepancy in more detail. While during inference the model receives temporal information from the beginning of the video to the current time step $t$ , in training, the model is provided with temporal information from $t - L$ to $t$ . Consequently, for each video, clips make predictions using the hidden state that lacks temporal information, which critically affects the losses associated with the early predictions. However, we observe that the conventional approach unknowingly assigns the same uniform weight to all losses for each time step. Our proposed method applies different weights to losses at different time steps, resulting in better training convergence and improved model performance.", + "bbox": [ + 75, + 113, + 472, + 356 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.2. Alleviating Training-Inference Discrepancy", + "text_level": 1, + "bbox": [ + 76, + 363, + 444, + 380 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The conventional loss calculation for OAD follows the following cross-entropy calculation:", + "bbox": [ + 76, + 386, + 468, + 417 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n- \\sum_ {t = 1} ^ {L} \\sum_ {k = 0} ^ {K} \\alpha_ {t} \\hat {y} _ {t, k} \\log \\left(\\hat {s} _ {t, k}\\right), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 181, + 425, + 468, + 467 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\hat{y}_{t,k}$ and $\\hat{s}_{t,k}$ represent the ground truth and predicted logit at time $t$ , $\\alpha_{t} \\in \\{\\alpha_{1}, \\alpha_{2}, \\dots, \\alpha_{L}\\}$ is the weight applied to the loss at each time step, and $K$ and $L$ are the number of classes and the length of the clip, respectively. We pay attention to the fact that the conventional approach has been unknowingly setting the weight $\\alpha_{t}$ uniformly for every time-step in the clip, resulting in $\\alpha_{t} = 1 / L$ . However, we show that setting weights uniformly like this, equivalent to using the joint prediction of all time steps, hinders the RNN from being effectively trained as it does not resemble the inference stage.", + "bbox": [ + 75, + 474, + 468, + 638 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Our goal is to alleviate the problem caused by the discrepancy between the training and inference stages. To do so, we first pay careful attention to what is happening in the inference stage where RNN's temporal capacity plays an important role. During the inference stage, temporal information can accumulate as much as the length of the whole video. Although sequence-to-sequence modeling, in theory, can have an unlimited continuous context length, it is known to have a limited temporal capacity [30], the maximum amount of information in which the RNN can retain. For the task of handling streaming videos, as the videos are long, most predictions are made utilizing the information within its limited capacity. This means that RNN uses the temporal information within RNN's temporal capacity for most predictions during inference.", + "bbox": [ + 75, + 640, + 470, + 866 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Selected Weights. From the above reasons, we choose to apply the weights that enable the RNN to utilize its maxi-", + "bbox": [ + 75, + 869, + 468, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "mum temporal capacity. The weight $\\alpha_{t}$ is set as:", + "bbox": [ + 500, + 90, + 821, + 106 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\alpha_ {t} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f} t = L \\\\ 0 & \\text {O t h e r w i s e} \\end{array} , \\right. \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 616, + 113, + 890, + 154 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "which is a step function that equals putting masks on all the loss except for the loss at the very last time step in the clip. Applying weights like this during training allows us to 1) disregard the dominant predictions made by using an uninformative hidden state and 2) train the RNN using predictions made by the RNN's sufficient temporal capacity, both of which better reflect the inference stage. As long as the length of the clip $L$ is reasonable enough to exploit RNN's full potential, the prediction made at the end of the clip is more representative of what is actually happening in the inference stage. The choice of $L$ , the length of the clip which directly affects the receptive field of RNN during training, is further experimented with in Section 5.2.", + "bbox": [ + 496, + 159, + 890, + 354 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "While the concept is very simple, its impact on the performance is substantial. By addressing the training-inference discrepancy, the model is able to learn more effectively. Section 5.3 provides further experiments on various weight choices that support the choice of our weights.", + "bbox": [ + 496, + 356, + 890, + 431 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. Experimental Setup", + "text_level": 1, + "bbox": [ + 498, + 443, + 692, + 460 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.1. Dataset", + "text_level": 1, + "bbox": [ + 500, + 468, + 594, + 483 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Similar to prior works on online action detection, we evaluate MiniROAD on two publicly-available datasets: THUMOS'14 and TVSeries. In addition, we use a large FineAction dataset for performance evaluation.", + "bbox": [ + 496, + 491, + 890, + 551 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "THUMOS'14 [19] comprises over 20 hours of sports video, e.g. baseball pitch, each annotated with 20 actions. Following the prior works [3, 43], we train on the validation set (200 untrimmed videos) and evaluate on the test set (213 untrimmed videos).", + "bbox": [ + 496, + 551, + 890, + 626 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "TVSeries [7] consists of 27 episodes of six popular TV shows, spanning 16 hours. It is annotated with 30 real-life everyday actions like opening doors, running, and drinking. It proposes unique challenges as it has a diverse viewpoint, heavy occlusion, and a large portion of background frames.", + "bbox": [ + 496, + 627, + 890, + 702 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "FineAction [24] is a large dataset introduced for Temporal Action Detection with more detailed activity descriptions with varying difficulties. It consists of 16,732 untrimmed videos spanning 705 video hours with 103,324 temporal instances of 106 action categories.", + "bbox": [ + 496, + 703, + 890, + 779 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4.2. Setting", + "text_level": 1, + "bbox": [ + 500, + 786, + 591, + 801 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Feature Extraction. As the selection of a feature extractor is an important factor that directly affects the performance, we follow the experimental settings of the state-of-the-art methods [43, 3, 40]. For THUMOS and TVSeries, we first sample the videos into 24 FPS and feed non-overlapping snippets to the feature extractor. The snippet", + "bbox": [ + 496, + 809, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "10344", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "size is set to 6 and TSN [34] is adopted as the feature extractor. We employ implementation and checkpoints from MMACTION [6] and experiment with feature extractors pretrained on Kinetics-400 [2] and Activitynet1.3 [17]. For FineAction Dataset, we use the officially available features extracted using a Two-Stream architecture [32]. This architecture feeds non-overlapping snippets of 16 RGB or optical flow frames to two separate I3D [2] models that were pretrained with Kinetics. Since the officially available feature is too condensed (16 frames being converted into one feature) and causes overlooking of the fine-grained action instances, we linearly interpolate the temporal resolution of the feature sequence by a factor of four. For all experiments, the visual and motion features are concatenated along the channel dimension before feeding into the model.", + "bbox": [ + 75, + 90, + 472, + 316 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Implementation Details. To substantiate our claim that mitigating the training-inference discrepancy leads to more effective training of RNN models, we adopt a minimalist approach in designing our model. Our model comprises an embedding layer, a GRU, and a classification layer. Despite its simplicity, our model achieves comparable or even better performance to the state-of-the-art methods thanks to maximizing RNN's potential with our proposed methodology, while its lightweight property makes it highly efficient.", + "bbox": [ + 75, + 320, + 468, + 455 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Implementation details can be found in the officially available code. Experiments are conducted using Nvidia RTX3090 Graphics cards.", + "bbox": [ + 76, + 457, + 468, + 503 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4.3. Evaluation Metrics", + "text_level": 1, + "bbox": [ + 76, + 513, + 261, + 529 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To evaluate the performance of our methodology, we follow prior works and report per-frame mean Average Precision (mAP) on the THUMOS'14 dataset and per-frame mean calibrated Average Precision (mcAP) on the TVSeries dataset. Per-frame mAP is adopted for the FineAction Dataset as well. For measuring mAP, we collect all the classification scores for each frame and calculate the precision and recall based on the sorted results. We then calculate the Average Precision for each class using the precision and recall values and average the results over all classes to obtain the mAP. The mcAP, introduced by [7] with the TVSeries dataset, was proposed to address the imbalance between positive and negative samples. Calibrated average precision (cAP) is calculated using the formula", + "bbox": [ + 75, + 537, + 468, + 750 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nc A P = \\frac {\\sum_ {i} c P r e c (i) \\cdot I (i)}{\\sum_ {i} I (i)}, \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 174, + 760, + 468, + 796 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $I(i)$ is 1 if the frame $i$ is a true positive and $cPrec$ is calculated by", + "bbox": [ + 76, + 806, + 468, + 837 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nc P r e c = \\frac {w \\cdot T P}{w \\cdot T P + F P}. \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 186, + 848, + 468, + 880 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $w$ is the ratio between negative and positive samples.", + "bbox": [ + 76, + 885, + 467, + 901 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/e939f9a725d8fbecdd9d11517bb197c582db758f0063f3ed7fe81e646e16a18c.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodBackboneParametersGFLOPsmAP (%)
TRN[39]402.9M1.4662.1
OadTR[36]75.8M2.5465.2
LSTR[40]TSN58.0M7.5369.5
GateHUB[3](Kinetics)45.2M6.9870.7
TeSTra[43]58.9M4.3771.2
MiniROAD (Ours)15.8M0.015871.8
", + "bbox": [ + 501, + 88, + 893, + 178 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Table 1: Comparison to other recent OAD methods in terms of parameter count, GFLOPs, and mAP on THUMOS'14 dataset using the Kinetics pretrained feature extractor.", + "bbox": [ + 498, + 193, + 892, + 239 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5. Results and Analysis", + "text_level": 1, + "bbox": [ + 500, + 257, + 697, + 273 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.1. Comparisons with State of the Art", + "text_level": 1, + "bbox": [ + 500, + 287, + 799, + 303 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "THUMOS'14. Table 1 presents a comparison of MiniROAD with recent methods on THUMOS'14, using features extracted by the Kinetics-pretrained TSN backbone. We measured the parameter count and GFLOPs of TeSTra and ours by ourselves, and the other numbers are from [3]. We can see that MiniROAD outperforms state-of-the-art methods on THUMOS'14 by $0.6\\%$ in mAP while requiring only $0.4\\%$ GFLOPs and $27\\%$ parameters. There is a significant gain in efficiency thanks to the RNN architecture. RNN's advantage in efficiency can be also seen by TRN. Despite its large number of parameters, TRN requires the least number of computations compared to the recent works as recent works employ transformer architecture that needs a lot more computation overhead for calculating attention. These large gains in efficiency suggest that RNNs have a significant advantage in online settings, specifically for those that require real-time processing. To validate the generalization of our method, we also evaluate the same dataset using the feature extractor pretrained with Activitynet. The results are shown in Table 2a and our method achieves the best results in this setting as well.", + "bbox": [ + 496, + 315, + 892, + 632 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "TVSeries. Table 2b shows the comparison of our method with the other methods using the features extracted by Kinetics and Activitynet pretrained features. Our method is able to achieve comparable or better performance to the state-of-the-art in this dataset as well.", + "bbox": [ + 498, + 638, + 890, + 713 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "FineAction. Table 3 compares the performance of our approach and recent methods on the FineAction Dataset. As we are the first to evaluate this dataset for the OAD task, we reproduced all the results in Table 3 using the publicly available code. Our model outperforms the recent methods, achieving a $17\\%$ performance gain over the next best-performing method. This dataset is much larger and contains activities of varying difficulties, in contrast to previously tested datasets that had limited action instances of similar categories. Thus, it provides a more realistic setting and can serve as a valuable benchmark for future OAD research.", + "bbox": [ + 496, + 719, + 893, + 898 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "10345", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/52118ca442809baf475eefe59ce2ca8cfb3e958f6cb2ad7d9b90ee97e81a4185.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodmAP (%)MethodmcAP (%)
AnetKineticsAnetKinetics
RED [14]45.3-RED[14]79.2-
IDN [12]50.060.3FATS[21]81.784.6
FATS [21]51.659.0IDN[12]84.786.1
TRN [39]47.262.1TRN[39]83.786.2
LAP [29]53.3-TFN[13]85.0-
TFN [13]55.7-LAP[29]85.3-
OadTR [36]58.365.2PKD[42]-86.4
LSTR [40]65.369.5OadTR[36]85.487.2
GateHUB [3]69.170.7LSTR[40]88.189.1
TeSTra [43]68.271.2GateHUB[3]88.489.6
Ours69.371.8Ours88.589.6
", + "bbox": [ + 78, + 88, + 460, + 261 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/963d2acfcafe4caea54f290014d31cf2702cf05e1d5cee805a73e77cb457101d.jpg", + "table_caption": [ + "(a)", + "(b)", + "Table 2: Comparison to other OAD methods on (a) THUMOS'14 [19] dataset and (b) TVSeries dataset [7]. Results using the backbone pre-trained using Activitynet [17] and Kinetics [2] are shown." + ], + "table_footnote": [], + "table_body": "
MethodmAP (%)
OadTR[36]31.8
LSTR[40]31.6
TeSTra[43]31.2
Ours37.1
", + "bbox": [ + 163, + 381, + 380, + 486 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 3: Comparison to other OAD methods on FineAction dataset [24].", + "bbox": [ + 75, + 501, + 468, + 531 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/3d811e11e5913d2d50001872ab829f7996a5a52deeeb9854715dd1190357a0a0.jpg", + "image_caption": [ + "Figure 3: Attention heatmap (top) and its specific values (bottom) of the transformer encoders in OadTR [36]. For the heatmap calculation, all the attention values in the encoder (of every layer and head) are collected for the entire test set input which are then averaged out over the heads. The above shows the collected values after normalization." + ], + "image_footnote": [], + "bbox": [ + 112, + 561, + 416, + 770 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.2. Why is RNN adequate for the task?", + "text_level": 1, + "bbox": [ + 500, + 90, + 807, + 107 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "The prevailing reasoning behind the lower performance of RNNs is that they struggle with learning long-range dependencies. This is often attributed to training difficulties such as gradient vanishing that can arise when processing prolonged sequences. Therefore, recent works have been using transformers for OAD as they are particularly proficient at capturing long-term dependencies. However, it is worth asking how much temporal information is actually needed for OAD.", + "bbox": [ + 496, + 113, + 890, + 248 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "What do Transformers Actually See? Inspired by the recent success of transformer models in OAD, we analyzed the attention weights within the transformer multi-head attention to gain insights into the model's decision-making process. The visualization results are presented in Figure 3. As evident from the heat map and the graph, the transformer model predominantly focuses on the recent and neighboring frames, indicating the recent input's dominant influence on the prediction. Surprisingly, despite the transformer's intended capability of capturing long-term dependencies, the model mainly relies on the recent frames for making the current frame prediction. Our analysis reinforces the argument that RNN's inductive bias, which prioritizes the current input while retaining meaningful temporal information from the past, is well suited for the task.", + "bbox": [ + 496, + 255, + 892, + 482 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Optimal Length of Temporal Information. Figure 4 shows the performance of our model with varying clip lengths using the proposed methodology. As our methodology trains the model with the loss computed at the end of the clip, the graph shows the trade-off between providing more temporal information and ignoring the supervision of the earlier steps. The figure shows that a saturation point is reached at 32 seconds and providing more information than 32 seconds does not improve the performance. To the commonly held belief that the RNN does not benefit from prolonged sequence length, there exists a model's maximum capacity. It is important to note, however, that RNN's capacity is already enough to perform well on the OAD task, validated by the promising performances shown in Section 5.1. A slight drop in performance after 32 seconds is a result of RNN not being able to use temporal information beyond a certain point and much supervision lost during training.", + "bbox": [ + 496, + 489, + 892, + 746 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.3. What is the optimal weight?", + "text_level": 1, + "bbox": [ + 500, + 756, + 750, + 772 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Our work shows that the uniform weights put on computed loss at each time-step hinders the effective training of the RNNs. To make the most use of the finding, we experimented with varying weight choices $\\alpha_{t}$ in (1) at each time step. Different choices of weights including uniform, linearly increasing, exponentially increasing, learnable, and step function, are experimented. The results are shown in Table 4a. The results indicate that assigning uniform", + "bbox": [ + 496, + 780, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "10346", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/54190922a5acbd615dde3e21acd069b8799e42f9ff1968863e756a1de2a561b7.jpg", + "image_caption": [ + "Effect of Hidden State Duration on THUMOS 14", + "Figure 4: Effect of varying the length of the clip $L$ during training." + ], + "image_footnote": [], + "bbox": [ + 107, + 116, + 416, + 287 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "weights to the loss computed at each time-step results in the worst performance, which is consistent with the findings discussed in the paper that this conventional approach impedes the effective training of the model. Applying linearly increasing weights performs better than assigning uniform weights because it places less emphasis on early-stage predictions. The next best performing choice is exponentially increasing weights, which heavily emphasizes the loss computed at later stages. The next best performing weight choice is learnable weights. For this experimental setup, learnable embeddings of size $L$ (length of the clip) were trained. When computing the loss, we apply softmax activation to the learnable weights, which are then multiplied by their corresponding loss at their time steps. This approach shows even better performance than exponentially increasing weights. The best-performing choice of weight is step-function which uses only the loss computed at the end. This results in the best performance as the loss associated with predictions using the informative hidden state best resemble the dominant predictions made at the inference stage.", + "bbox": [ + 75, + 359, + 472, + 679 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.4. Effectiveness of the method", + "text_level": 1, + "bbox": [ + 76, + 705, + 323, + 720 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 4b shows the result of our model with and without the proposed non-uniform weights. We can observe that there is a $5\\%$ mAP increase by using our proposed methodology. In addition, we also experiment with our proposed methodology using the transformer architecture. For the experiment, we adopt the transformer encoder from OadTR and set the encoding layers to 3 and the number of heads to 8 which is the default setting in the publicly available code. We observe that the performance increases from 63.0 to $64.9\\%$ mAP with a $1.9\\%$ mAP increase using our proposed methodology.", + "bbox": [ + 75, + 734, + 468, + 902 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/2c23386c7975ac229e8195f510dce889007c97b625c799f66dc6410c05cfc939.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Weight TypemAP (%)
Uniform66.4
Linear68.6
Exponential69.8
Learnable70.8
Step-Function71.8
", + "bbox": [ + 501, + 89, + 689, + 181 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/9058fe8319b4d7756e7aaf39484bdd03908a22f57c96d388dfebe4f5816ef234.jpg", + "table_caption": [ + "(a)" + ], + "table_footnote": [], + "table_body": "
Method
TransformerMiniROAD
Uniform Weight63.066.4
Proposed64.971.8
", + "bbox": [ + 692, + 101, + 893, + 170 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/d4119cb2924a78452f556a3548b87b6c12c274a9622ae848d9f1d7d6d527286a.jpg", + "table_caption": [ + "(b)", + "Table 4: (a) Result of applying different weights $\\alpha_{t}$ in (1). Otherwise stated, Step-Function is the default choice in our paper which only uses the loss computed at the end of the clip. (b) Result of applying the proposed weights on the transformer-based model and on our model." + ], + "table_footnote": [], + "table_body": "
MethodOF. Comp.RGB Feat.OF. Feat.Model FPSOverall FPSmAP (%)
TRN14320.562.1
OadTR14520.565.2
LSTR28.838321918721.269.5
TeSTra16920.971.2
Ours3730023.871.8
", + "bbox": [ + 501, + 306, + 890, + 420 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 5: Runtime Comparison of OAD methods on THU-MOS'14 dataset with flow features extracted using TV-L1 [41] algorithm. OF. Comp., RGB Feat., and OF. Feat. are the speed of extracting optical flows, rgb features, and optical flow features respectively, measured in FPS.", + "bbox": [ + 498, + 435, + 892, + 512 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.5. Runtime", + "text_level": 1, + "bbox": [ + 500, + 530, + 604, + 544 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Efficiency is a critical aspect of the online nature of the OAD task. To assess efficiency, we compare MiniROAD's runtime with recent methods in frames per second (FPS) using videos from the THUMOS'14 dataset on a system with a single RTX3090 GPU. The results in Table 5 demonstrate that our model's lightweight RNN architecture is very efficient, running about 200 times faster than previous methods. However, it is worth noting that the model's speed is not the final speed, as the input of the OAD model requires the extraction of visual and motion features. As illustrated in Table 5, computing optical flow accounts for the majority of the computation time. The end-to-end speed, which encompasses the speed after computing optical flows, extracting visual and motion features, and passing through the model, is reported as Overall FPS in the table. Although extracting optical flow acts as a bottleneck, the efficiency of our model yields 2.9 gains in FPS overall. These gains in overall speed are further improved when a faster optical flow computing algorithm is used. To demonstrate the efficacy of this approach, we also test using the NVIDIA Optical Flow $\\mathrm{SDK}^1$ (NVOFA) for faster optical flow computa", + "bbox": [ + 496, + 554, + 890, + 872 + ], + "page_idx": 6 + }, + { + "type": "page_footnote", + "text": "1https://developer.nvidia.com/opticalflow-sdk", + "bbox": [ + 517, + 886, + 759, + 898 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "10347", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/a3efae55b464afa718fc8df08e78d6465d3cac5430dbd8dab126e73bae13b4b3.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodPre-TrainmAP@τ0Average
0.250.50.7511.251.51.752
RED [14]45.342.139.637.535.834.433.232.137.5
TRN [39]45.142.440.739.137.736.435.334.338.9
TTM [35]45.943.742.441.039.939.437.937.340.9
LAP-Net [29]49.047.445.343.241.339.738.337.042.6
OadTR [36]ANet1.350.249.348.146.845.343.942.441.145.9
LSTR [40]--------50.1
GateHUB [3]--------54.2
TeSTra [43]64.761.858.755.753.251.149.247.855.3
Ours65.463.360.557.454.851.949.747.756.3
TTM [35]46.845.544.643.641.941.140.438.742.8
LSTR [36]60.458.656.053.350.948.947.145.752.6
OadTR [36]K40059.858.556.654.652.650.548.646.853.5
TeSTra [43]66.263.560.557.454.852.650.548.956.8
Ours68.566.363.560.757.955.653.551.459.7
", + "bbox": [ + 133, + 88, + 834, + 290 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/4331211540c426377d4302aff61ef9d212c9fbe6dd7f2c725e6e34acc1ed386f.jpg", + "table_caption": [ + "Table 6: Action Anticipation Results on THUMOS'14 dataset with feature extractor pretrained with Activitynet (top) and Kinetics (bottom)." + ], + "table_footnote": [], + "table_body": "
MethodOF. Comp.RGB Feat.OF. Feat.Model FPSOverall FPSmAP (%)
TRN†14366.061.6
OADTR†14566.363.3
LSTR†1K38321918773.867.1
TeSTra16970.967.3
Ours3730012268.4
", + "bbox": [ + 78, + 347, + 468, + 460 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 7: Comparison to other OAD methods on THU-MOS'14 dataset with flow features extracted using NVIDIA OPTICAL FLOW. $\\dagger$ was reproduced by us. All the values indicate the speed measured in FPS.", + "bbox": [ + 75, + 474, + 468, + 535 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "tion, which runs at around 1K FPS. By utilizing the faster flow algorithm, our model runs at 122 FPS which is 1.72 times faster than the state-of-the-art model. Although there is a degradation in the final performance compared to the traditionally used flow algorithm, this highlights the availability of an alternative approach that can deliver faster end-to-end speed while balancing performance and speed trade-offs. The significant increase in end-to-end speed when using the faster optical flow algorithm indicates that additional increases can be gained with RGB-only inputs, leaving open opportunities for future work.", + "bbox": [ + 75, + 551, + 468, + 717 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.6. Action Anticipation", + "text_level": 1, + "bbox": [ + 76, + 726, + 264, + 742 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "As our methodology is also applicable to other online tasks, we extend our method to Action Anticipation, which is a task of anticipating upcoming actions using the histories. Instead of predicting the current time frame, the model is trained to predict the next upcoming actions every 0.25 seconds up to 2 seconds. Table 6 shows the results of predictions at each of that time-step. It shows that our method performs favorably to the other methods with $1\\%$ mAP gain using activitynet pretrained backbone and $2.9\\%$ mAP gain using kinetics pretrained backbone over the previous state", + "bbox": [ + 75, + 750, + 470, + 902 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "of-the-art. While our methodology was initially designed for OAD, its applicability extends beyond OAD and can be used for other similar tasks.", + "bbox": [ + 496, + 351, + 890, + 396 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 411, + 617, + 426 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We revisit RNN for online action detection and show its potential in dealing with the task. We identify the training-inference discrepancy as a primary cause of the lower performance of RNNs and address the issue by introducing non-uniform weights to the loss computed at each timesteps. We demonstrate the effectiveness of our proposed method using MiniROAD, a minimal RNN-based OAD model. MiniROAD achieves equal or better accuracy than the existing best method on challenging datasets, with a significant increase in efficiency. With the faster NVOFA, MiniROAD runs at an impressive 122 FPS.", + "bbox": [ + 496, + 436, + 890, + 602 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We note that recent OAD methods rely heavily on optical flows, which impede end-to-end speed. While faster optical flow algorithms like NVOFA can mitigate this issue, flow-free OAD remains an open yet challenging problem. By highlighting the suitability of RNNs for processing streaming videos, we hope to pave the way for further advancements and shed light on developing more efficient models.", + "bbox": [ + 496, + 603, + 890, + 709 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgements", + "text_level": 1, + "bbox": [ + 500, + 724, + 666, + 739 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "This work was supported by Samsung Electronics Co., Ltd. (Mobile eXperience Business), Yonsei University Artificial Intelligence Graduate School Program under Grant 2020-0-01361, and by the Institute of Information & communications Technology Planning & Evaluation (IITP) grant funded by the Korea government(MSIT) (No.2022-0-00124, Development of Artificial Intelligence Technology for Self-Improving Competency-Aware Learning Capabilities). The work of Joungbin was in part supported by the Hyundai Motor Chung Mong-Koo Foundation.", + "bbox": [ + 496, + 750, + 890, + 901 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "10348", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lučić, and Cordelia Schmid. Vivit: A video vision transformer. In IEEE International Conference on Computer Vision (ICCV), pages 6836-6846, 2021. 3", + "[2] Joao Carreira and Andrew Zisserman. Quo vadis, action recognition? a new model and the kinetics dataset. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 6299-6308, 2017. 5, 6", + "[3] Junwen Chen, Gaurav Mittal, Ye Yu, Yu Kong, and Mei Chen. Gatehub: Gated history unit with background suppression for online action detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 3, 4, 5, 6, 8", + "[4] Kyunghyun Cho, Bart Van Merrienboer, Caglar Gulcehre, Dzmitry Bahdanau, Fethi Bougares, Holger Schwenk, and Yoshua Bengio. Learning phrase representations using rnn encoder-decoder for statistical machine translation. arXiv preprint arXiv:1406.1078, 2014. 2", + "[5] Junyoung Chung, Caglar Gulcehre, KyungHyun Cho, and Yoshua Bengio. Empirical evaluation of gated recurrent neural networks on sequence modeling. arXiv preprint arXiv:1412.3555, 2014. 1, 3", + "[6] MMAction2 Contributors. Openmmlab's next generation video understanding toolbox and benchmark. https://github.com/open-mmlab/mmaction2, 2020.5", + "[7] Roeland De Geest, Efstratios Gavves, Amir Ghodrati, Zhenyang Li, Cees Snoek, and Tinne Tuytelaars. Online action detection. In European Conference on Computer Vision (ECCV), pages 269-284. Springer, 2016. 1, 2, 4, 5, 6", + "[8] Roeland De Geest and Tinne Tuytelaars. Modeling temporal structure with lstm for online action detection. In IEEE Winter Conference on Applications of Computer Vision (WACV), pages 1549-1557. IEEE, 2018. 2", + "[9] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. arXiv preprint arXiv:1810.04805, 2018. 1, 3", + "[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020. 1, 3", + "[11] Jeffrey L Elman. Finding structure in time. Cognitive science, 14(2):179-211, 1990. 1", + "[12] Hyunjun Eun, Jinyoung Moon, Jongyoul Park, Chanho Jung, and Changick Kim. Learning to discriminate information for online action detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2020. 2, 6", + "[13] Hyunjun Eun, Jinyoung Moon, Jongyoul Park, Chanho Jung, and Changick Kim. Temporal filtering networks for online action detection. Pattern Recognition, 111:107695, 2021. 6", + "[14] Jiyang Gao, Zhenheng Yang, and Ram Nevatia. Red: Reinforced encoder-decoder networks for action anticipation. arXiv preprint arXiv:1707.04818, 2017. 2, 6, 8" + ], + "bbox": [ + 78, + 114, + 470, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[15] Mingfei Gao, Yingbo Zhou, Ran Xu, Richard Socher, and Caiming Xiong. Woad: Weakly supervised online action detection in untrimmed videos. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1915-1923, 2021. 2", + "[16] Albert Gu, Karan Goel, and Christopher Ré. Efficiently modeling long sequences with structured state spaces. arXiv preprint arXiv:2111.00396, 2021. 3", + "[17] Fabian Caba Heilbron, Victor Escorcia, Bernard Ghanem, and Juan Carlos Niebles. Activitynet: A large-scale video benchmark for human activity understanding. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 961-970. IEEE, 2015. 5, 6", + "[18] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 9(8):1735-1780, 1997. 1, 2, 3", + "[19] Haroon Idrees, Amir R Zamir, Yu-Gang Jiang, Alex Gorban, Ivan Laptev, Rahul Sukthankar, and Mubarak Shah. The thumos challenge on action recognition for videos \"in the wild\". Computer Vision and Image Understanding(CVIU), 155:1-23, 2017. 4, 6", + "[20] Jinkyu Kim, Teruhisa Misu, Yi-Ting Chen, Ashish Tawari, and John Canny. Grounding human-to-vehicle advice for self-driving vehicles. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 10591–10599, 2019. 1", + "[21] Young Hwi Kim, Seonghyeon Nam, and Seon Joo Kim. Temporally smooth online action detection using cycle-consistent future anticipation. Pattern Recognition, 116:107954, 2021. 2, 6", + "[22] Serkan Kiranyaz, Onur Avci, Osama Abdeljaber, Turker Ince, Moncef Gabbouj, and Daniel J Inman. 1d convolutional neural networks and applications: A survey. Mechanical systems and signal processing, 151:107398, 2021. 3", + "[23] Zachary C Lipton, John Berkowitz, and Charles Elkan. A critical review of recurrent neural networks for sequence learning. arXiv preprint arXiv:1506.00019, 2015. 1, 2", + "[24] Yi Liu, Limin Wang, Yali Wang, Xiao Ma, and Yu Qiao. Fineaction: A fine-grained video dataset for temporal action localization. IEEE Transactions on Image Processing, 2022, 4, 6", + "[25] Antonio Orvieto, Samuel L Smith, Albert Gu, Anushan Fernando, Caglar Gulcehre, Razvan Pascanu, and Soham De. Resurrecting recurrent neural networks for long sequences. arXiv preprint arXiv:2303.06349, 2023. 3", + "[26] Guansong Pang, Cheng Yan, Chunhua Shen, Anton van den Hengel, and Xiao Bai. Self-trained deep ordinal regression for end-to-end video anomaly detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 12173-12182, 2020. 1", + "[27] Hyunjong Park, Jongyoun Noh, and Bumsub Ham. Learning memory-guided normality for anomaly detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 14372-14381, 2020. 1", + "[28] Bo Peng, Eric Alcaide, Quentin Anthony, Alon Albalak, Samuel Arcadinho, Huanqi Cao, Xin Cheng, Michael Chung, Matteo Grella, Kranthi Kiran GV, et al. Rwkv:" + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "10349", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "Reinventing rnns for the transformer era. arXiv preprint arXiv:2305.13048, 2023. 3", + "[29] Sanqing Qu, Guang Chen, Dan Xu, Jinhu Dong, Fan Lu, and Alois Knoll. Lap-net: Adaptive features sampling via learning action progression for online action detection. arXiv preprint arXiv:2011.07915, 2020. 6, 8", + "[30] Mike Schuster and Kuldip K Paliwal. Bidirectional recurrent neural networks. IEEE transactions on Signal Processing, 45(11):2673-2681, 1997. 1, 4", + "[31] Tianmin Shu, Dan Xie, Brandon Rothrock, Sinisa Todorovic, and Song Chun Zhu. Joint inference of groups, events and human roles in aerial videos. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 4576-4584, 2015. 1", + "[32] Karen Simonyan and Andrew Zisserman. Two-stream convolutional networks for action recognition in videos. Conference on Neural Information Processing Systems (NeurIPS), 27, 2014. 5", + "[33] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Conference on Neural Information Processing Systems (NeurIPS), 30, 2017. 1, 3", + "[34] Limin Wang, Yuanjun Xiong, Zhe Wang, Yu Qiao, Dahua Lin, Xiaou Tang, and Luc Van Gool. Temporal segment networks: Towards good practices for deep action recognition. In European Conference on Computer Vision (ECCV), pages 20-36. Springer, 2016. 5", + "[35] Wen Wang, Xiaojiang Peng, Yanzhou Su, Yu Qiao, and Jian Cheng. Tpp: Temporal transformer with progressive prediction for efficient action anticipation. Neurocomputing, 438:270-279, 2021. 8", + "[36] Xiang Wang, Shiwei Zhang, Zhiwu Qing, Yuanjie Shao, Zhengrong Zuo, Changxin Gao, and Nong Sang. Oadtr: Online action detection with transformers. IEEE International Conference on Computer Vision (ICCV), 2021. 2, 5, 6, 8", + "[37] Paul J Werbos. Backpropagation through time: what it does and how to do it. Proceedings of the IEEE, 78(10):1550-1560, 1990. 2", + "[38] Chao-Yuan Wu, Yanghao Li, Karttikeya Mangalam, Haoqi Fan, Bo Xiong, Jitendra Malik, and Christoph Feichtenhofer. Memvit: Memory-augmented multiscale vision transformer for efficient long-term video recognition. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 13587-13597, 2022. 3", + "[39] Mingze Xu, Mingfei Gao, Yi-Ting Chen, Larry S. Davis, and David J. Crandall. Temporal recurrent networks for online action detection. In IEEE International Conference on Computer Vision (ICCV), 2019. 2, 5, 6, 8", + "[40] Mingze Xu, Yuanjun Xiong, Hao Chen, Xinyu Li, Wei Xia, Zhuowen Tu, and Stefano Soatto. Long short-term transformer for online action detection. In Conference on Neural Information Processing Systems (NeurIPS), 2021. 2, 4, 5, 6, 8", + "[41] Christopher Zach, Thomas Pock, and Horst Bischof. A duality based approach for realtime tv-l 1 optical flow. In Pattern Recognition, pages 214-223. Springer, 2007. 7" + ], + "bbox": [ + 78, + 90, + 468, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[42] Peisen Zhao, Lingxi Xie, Ya Zhang, Yanfeng Wang, and Qi Tian. Privileged knowledge distillation for online action detection. arXiv preprint arXiv:2011.09158, 2020. 6", + "[43] Yue Zhao and Philipp Krahenbuhl. Real-time online video detection with temporal smoothing transformers. In European Conference on Computer Vision (ECCV), 2022. 3, 4, 5, 6, 8" + ], + "bbox": [ + 501, + 92, + 890, + 189 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "10350", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/ea56ef7d-d0ee-4b4c-86bd-22698b72c0f8_model.json b/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/ea56ef7d-d0ee-4b4c-86bd-22698b72c0f8_model.json new file mode 100644 index 0000000000000000000000000000000000000000..464a0a416b96ecc23518343e8195d41e49f8f352 --- /dev/null +++ b/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/ea56ef7d-d0ee-4b4c-86bd-22698b72c0f8_model.json @@ -0,0 +1,1958 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.143, + 0.131, + 0.828, + 0.151 + ], + "angle": 0, + "content": "MiniROAD: Minimal RNN Framework for Online Action Detection" + }, + { + "type": "text", + "bbox": [ + 0.13, + 0.18, + 0.84, + 0.218 + ], + "angle": 0, + "content": "Joungbin An\\(^{1}\\) Hyolim Kang\\(^{1}\\) Su Ho Han\\(^{1}\\) Ming-Hsuan Yang\\(^{1,2,3}\\) Seon Joo Kim\\(^{1}\\) \n\\(^{1}\\)Yonsei University \\(^{2}\\)UC Merced \\(^{3}\\)Google Research" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.252, + 0.314, + 0.267 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.284, + 0.474, + 0.618 + ], + "angle": 0, + "content": "Online Action Detection (OAD) is the task of identifying actions in streaming videos without access to future frames. Much effort has been devoted to effectively capturing long-range dependencies, with transformers receiving the spotlight for their ability to capture long-range temporal structures. In contrast, RNNs have received less attention lately, due to their lower performance compared to recent methods that utilize transformers. In this paper, we investigate the underlying reasons for the inferior performance of RNNs compared to transformer-based algorithms. Our findings indicate that the discrepancy between training and inference is the primary hindrance to the effective training of RNNs. To address this, we propose applying non-uniform weights to the loss computed at each time step, which allows the RNN model to learn from the predictions made in an environment that better resembles the inference stage. Extensive experiments on three benchmark datasets, THU-MOS, TVSeries, and FineAction demonstrate that a minimal RNN-based model trained with the proposed methodology performs equally or better than the existing best methods with a significant increase in efficiency. The code is available at https://github.com/jbistanbul/MiniROAD." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.647, + 0.21, + 0.663 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.673, + 0.47, + 0.84 + ], + "angle": 0, + "content": "Online Action Detection (OAD) is a challenging task that involves identifying actions taking place in a streaming video without access to future frames. Since its introduction [7], OAD has gained great attention in research circles, as it has numerous real-world applications, such as autonomous driving [20], smart surveillance systems [26, 27], and anomaly detection [31]. These applications require the ability to process streaming videos in real-time, making OAD an essential component of many advanced systems. As a result, there has been a growing interest in developing more accurate and efficient methods for performing OAD." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.471, + 0.902 + ], + "angle": 0, + "content": "To address the challenges of OAD, recent efforts have focused on developing novel models for analyzing streaming videos in real-time. The conventional process of OAD consists of two stages. In the first stage, frames are con" + }, + { + "type": "image", + "bbox": [ + 0.534, + 0.261, + 0.839, + 0.476 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.489, + 0.892, + 0.518 + ], + "angle": 0, + "content": "Figure 1: Performance of recent OAD methods with respect to GFLOPs and the model's size." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.534, + 0.894, + 0.625 + ], + "angle": 0, + "content": "verted into a sequence of features by a feature extractor. In the second stage, the extracted features are processed to capture the temporal information required for performing OAD. Much attention on OAD research has been paid to this second stage where the two mainstream models are RNNs [11, 30, 18, 5] and Transformers [9, 10, 33]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.627, + 0.895, + 0.761 + ], + "angle": 0, + "content": "Each model has its strengths and weaknesses. RNNs can capture temporal transitions effectively by modeling sequences recurrently but are known for their training difficulties [23, 30]. Transformers can capture long-term dependencies through self-attention, however, attention computation is computationally expensive. Although recent research has shifted towards using Transformer models, our paper revisits RNN, which has been overlooked in recent studies." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.895, + 0.903 + ], + "angle": 0, + "content": "In this work, we show that RNN's intrinsic inductive bias—prioritizing the current input while preserving meaningful temporal information from the histories—makes them well-suited for OAD. Unlike in natural language processing, where a distant word can significantly affect the next sequence prediction, we observe that in OAD, the current and its neighboring frames have a dominant influence on the current prediction. In addition, RNN is efficient, as it requires a small computational overhead compared to" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "10341" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.47, + 0.122 + ], + "angle": 0, + "content": "the transformer models, making them well-suited for online tasks that require running in real-time." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.124, + 0.468, + 0.244 + ], + "angle": 0, + "content": "Despite its architecture being well-suited for the OAD task, RNN has been recently overlooked due to the promising results shown by transformer-based models. The prevailing reasoning behind the lower performance of RNN based method was the difficulty of learning long-range dependencies [37, 23]. In this paper, we find that it is the training-inference discrepancy that hinders the effective training of RNNs." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.247, + 0.468, + 0.534 + ], + "angle": 0, + "content": "During inference, the video is processed frame-by-frame in a streaming fashion. During training, however, the video is divided into multiple clips, which are then fed to the model, as illustrated in Figure 2. This creates a significant discrepancy between the two phases since videos are usually much longer than the training clips. Consequently, the clips provide limited temporal information, leading to a restricted view of the video during training. This limitation is not as problematic for recent OAD models using transformers as it is for models using RNNs. This is because recent transformer models utilize the temporal information between clips using explicit long-term memory even during training. At the same time, RNNs do not since they receive a non-informative hidden state initialized as zero at the beginning of the clip. As a result, RNNs make most predictions during training with the hidden state that lacks temporal information, whereas it makes most predictions during inference with the hidden state accumulated with sufficient temporal information." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.536, + 0.468, + 0.822 + ], + "angle": 0, + "content": "We demonstrate that addressing the training and inference discrepancy in RNNs alone can significantly improve their performance without requiring any changes to their architecture. Specifically, we find that introducing nonuniform weights to losses at different time steps can alleviate this discrepancy, which is a primary factor contributing to RNN's suboptimal performance. This approach differs from the conventional assumption of averaging the loss over the joint prediction, as we demonstrate that non-uniform weights to the loss are essential for effectively training the model. We demonstrate the effectiveness of our methodology using Minimal Recurrent neural network for Online Action Detection (MiniROAD), which is a lightweight GRU based model. Figure 1 shows the comparison of our model with other recent models in terms of the model's performance, GFLOPs, and size. It shows that our method with only \\(\\sim 0.4\\%\\) computational power needed for the previous state-of-the-art, is able to achieve better performance." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.468, + 0.9 + ], + "angle": 0, + "content": "Our model is evaluated on conventional OAD benchmark datasets, including THUMOS'14 and TVSeries, as well as on the recently introduced FineAction dataset. As conventional datasets used for benchmarking OAD tasks are relatively small, the much larger FineAction dataset offers" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.198 + ], + "angle": 0, + "content": "a more challenging testbed that better depicts real-life scenarios. Larger datasets like FineAction open up more possibilities for future work on OAD and hence our results can serve as a strong baseline. Our experiments show that our proposed methodologies achieve on-par or better results on the benchmarked dataset with significant improvements in efficiency." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.199, + 0.788, + 0.212 + ], + "angle": 0, + "content": "The main contributions of this work are:" + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.215, + 0.892, + 0.304 + ], + "angle": 0, + "content": "- We revisit the potential of RNNs and identify the training-inference discrepancy as a primary cause of their lower performance. To address this issue, we propose a simple yet effective method that makes RNN both effective and efficient in capturing the essential temporal information for online action detection." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.306, + 0.892, + 0.425 + ], + "angle": 0, + "content": "- Extensive experimental results show that the proposed method performs favorably against the state-of-the-art with high efficiency; our model with only \\(\\sim 0.4\\%\\) computational overhead compared to the existing methods, achieves on par or better performance on a challenging benchmark dataset, with \\(\\sim 17\\%\\) performance improvement over the state-of-the-art in a large-scale dataset." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.426, + 0.892, + 0.471 + ], + "angle": 0, + "content": "- We expand our methodology and carry out performance evaluation on Action Anticipation and show the applicability of our method on other online tasks." + }, + { + "type": "list", + "bbox": [ + 0.519, + 0.215, + 0.892, + 0.471 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.488, + 0.642, + 0.503 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.513, + 0.722, + 0.529 + ], + "angle": 0, + "content": "2.1. Online Action Detection" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.538, + 0.892, + 0.824 + ], + "angle": 0, + "content": "The Online Action Detection task [7] involves detecting actions in the current frame online, using information from the past up to the present. Earlier approaches to Online Action Detection relied on recurrent models. Geest et al. propose a two-stream feedback network [8], utilizing LSTM [18] where one stream focuses on feature representation and the other on temporal patterns. RED [14] takes advantage of reinforcement learning to make action predictions as early as possible. Recent works using RNNs focus on designing more effective RNN cells. TRN [39] models a greater temporal context by having the LSTM cell [18] anticipate the future. IDN [12] uses the GRU cell [4] to explicitly differentiate relevant information for ongoing actions. In [21], FATSnet employs GRU to perform future anticipation and temporal smoothing for more effective current prediction. On the other hand, WOAD [15] introduces a method for weakly supervised online action detection. Existing RNN-based models mainly concentrate on developing more powerful RNN architectures to handle the task." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Transformers have also been used for the OAD task. OadTR [36] introduces a transformer encoder-decoder architecture for capturing long-term relations through self-attention. In [40], LSTR achieves significant performance improvements by employing a two-stage memory compres" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "10342" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.134, + 0.087, + 0.844, + 0.285 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.296, + 0.895, + 0.374 + ], + "angle": 0, + "content": "Figure 2: Illustration of Training and Inference Discrepancy. During the inference stage (top), frames are fed to the model sequentially in a streaming fashion. The hidden state evolves across the entire video, progressively incorporating accumulated temporal context (depicted as darkening over time). In the training stage (bottom), the video is divided into shorter clips of length \\( L \\), serving as model inputs. Here, the model solely relies on temporal information within each clip, lacking inter-clip associations. This yields dominant predictions constrained by clip-specific information." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.388, + 0.473, + 0.539 + ], + "angle": 0, + "content": "sion design with transformers, allowing for capturing long-term temporal and short-term context through self-attention. This two-stage memory design has been further advanced in subsequent works. GateHUB [3] improves the two-stage architecture with a Gated History Unit to address the limitations of prior cross-attention methods. This avoids incorrect current frame predictions by appropriately weighting informative and uninformative frames. Recently, TeSTra [43] extends the LSTR architecture by introducing two temporal smoothing kernels to reduce inference computation cost." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.542, + 0.471, + 0.648 + ], + "angle": 0, + "content": "Although these transformer models have achieved state-of-the-art results, the attention computation involved in encoding long-term and short-term memory is computationally expensive. In this work, we show that RNNs, without modifying the internals of the architecture, can be just as effective in processing streaming videos with the proposed methodology alone." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.664, + 0.265, + 0.681 + ], + "angle": 0, + "content": "2.2. Sequence Modeling" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.69, + 0.473, + 0.902 + ], + "angle": 0, + "content": "As many real-world applications involve processing time-series data, sequential modeling has been a topic of ongoing research. Recurrent Neural Networks (RNNs) are one of the most commonly used models for sequence modeling, with popular variants including [18] and [5]. These variants introduce mechanisms within the RNN cell to improve its memory capacity while attending to important parts of the sequential data. 1D CNNs [22] incorporate convolution operations to capture the temporal structure of time-series data. Recent advances have been made using transformers [33] that incorporate attention mechanisms for capturing short and long-term dependencies. Ever since its success in the language domain, its use has been widespread in various fields [10, 9, 1, 38]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.388, + 0.895, + 0.616 + ], + "angle": 0, + "content": "There have been ongoing efforts on exploring non-transformer architectures. Gu et al. [16] introduces the State Space Model (SSM) in tackling sequence data, proving its efficacy in effectively handling long sequences. A recent work [25] demonstrates that RNNs can match the performance and training speed of SSMs by applying techniques such as linearizing and diagonalizing the recurrence, along with better parameterizations and initializations. Recently, there has been a notable surge in interest surrounding a novel variant of RNN called RWKV [28]. This architecture is the first non-transformer model to be successfully scaled to tens of billions of parameters, bringing together the efficient parallelizable training of transformers with the inference efficiency of RNNs. Our research aligns with these works in resurrecting RNNs in the transformer era." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.655, + 0.637, + 0.673 + ], + "angle": 0, + "content": "3. Methodology" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.69, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Provided a live streaming video, our objective is to recognize actions in the current frame based on past observations up to the current time. Since \\( v_{1}^{t} \\), a streaming video from the start until the current time \\( t \\) only provides observations \\( \\{v_{1},\\dots,v_{t}\\} \\) for the past \\( t \\) frames, it is not possible to access any information beyond \\( v_{t} \\). In this setting, the task is to use \\( v_{1}^{t} \\) to predict \\( \\hat{y}_t \\in \\{0,1,\\dots,K\\} \\) where \\( K \\) is the number of action classes and index 0 is the background class. During training, the video is divided into clips, each of length \\( L \\), and hence clips of \\( v_{t - L}^{t} \\) are given as input. Following the convention, we suppose that a pre-trained feature extractor is available which can convert each frame \\( v_{t} \\) into a feature vector \\( f_{t} \\in \\mathbb{R}^{C} \\). Our method employs the feature vector \\( f_{t} \\) as the input at current time \\( t \\) to predict \\( \\hat{y}_t \\)." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "10343" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.091, + 0.188, + 0.105 + ], + "angle": 0, + "content": "3.1. Overview" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.114, + 0.473, + 0.357 + ], + "angle": 0, + "content": "Our method is developed based on the observation that a discrepancy exists between the training and the inference stages, which hinders the effective training of sequence-to-sequence models. Figure 2 illustrates this training-inference discrepancy in more detail. While during inference the model receives temporal information from the beginning of the video to the current time step \\( t \\), in training, the model is provided with temporal information from \\( t - L \\) to \\( t \\). Consequently, for each video, clips make predictions using the hidden state that lacks temporal information, which critically affects the losses associated with the early predictions. However, we observe that the conventional approach unknowingly assigns the same uniform weight to all losses for each time step. Our proposed method applies different weights to losses at different time steps, resulting in better training convergence and improved model performance." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.364, + 0.446, + 0.381 + ], + "angle": 0, + "content": "3.2. Alleviating Training-Inference Discrepancy" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.387, + 0.47, + 0.418 + ], + "angle": 0, + "content": "The conventional loss calculation for OAD follows the following cross-entropy calculation:" + }, + { + "type": "equation", + "bbox": [ + 0.182, + 0.426, + 0.47, + 0.468 + ], + "angle": 0, + "content": "\\[\n- \\sum_ {t = 1} ^ {L} \\sum_ {k = 0} ^ {K} \\alpha_ {t} \\hat {y} _ {t, k} \\log \\left(\\hat {s} _ {t, k}\\right), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.475, + 0.47, + 0.64 + ], + "angle": 0, + "content": "where \\(\\hat{y}_{t,k}\\) and \\(\\hat{s}_{t,k}\\) represent the ground truth and predicted logit at time \\(t\\), \\(\\alpha_{t} \\in \\{\\alpha_{1}, \\alpha_{2}, \\dots, \\alpha_{L}\\}\\) is the weight applied to the loss at each time step, and \\(K\\) and \\(L\\) are the number of classes and the length of the clip, respectively. We pay attention to the fact that the conventional approach has been unknowingly setting the weight \\(\\alpha_{t}\\) uniformly for every time-step in the clip, resulting in \\(\\alpha_{t} = 1 / L\\). However, we show that setting weights uniformly like this, equivalent to using the joint prediction of all time steps, hinders the RNN from being effectively trained as it does not resemble the inference stage." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.641, + 0.471, + 0.867 + ], + "angle": 0, + "content": "Our goal is to alleviate the problem caused by the discrepancy between the training and inference stages. To do so, we first pay careful attention to what is happening in the inference stage where RNN's temporal capacity plays an important role. During the inference stage, temporal information can accumulate as much as the length of the whole video. Although sequence-to-sequence modeling, in theory, can have an unlimited continuous context length, it is known to have a limited temporal capacity [30], the maximum amount of information in which the RNN can retain. For the task of handling streaming videos, as the videos are long, most predictions are made utilizing the information within its limited capacity. This means that RNN uses the temporal information within RNN's temporal capacity for most predictions during inference." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.871, + 0.47, + 0.902 + ], + "angle": 0, + "content": "Selected Weights. From the above reasons, we choose to apply the weights that enable the RNN to utilize its maxi-" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.092, + 0.822, + 0.107 + ], + "angle": 0, + "content": "mum temporal capacity. The weight \\(\\alpha_{t}\\) is set as:" + }, + { + "type": "equation", + "bbox": [ + 0.617, + 0.114, + 0.892, + 0.155 + ], + "angle": 0, + "content": "\\[\n\\alpha_ {t} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f} t = L \\\\ 0 & \\text {O t h e r w i s e} \\end{array} , \\right. \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.16, + 0.892, + 0.356 + ], + "angle": 0, + "content": "which is a step function that equals putting masks on all the loss except for the loss at the very last time step in the clip. Applying weights like this during training allows us to 1) disregard the dominant predictions made by using an uninformative hidden state and 2) train the RNN using predictions made by the RNN's sufficient temporal capacity, both of which better reflect the inference stage. As long as the length of the clip \\( L \\) is reasonable enough to exploit RNN's full potential, the prediction made at the end of the clip is more representative of what is actually happening in the inference stage. The choice of \\( L \\), the length of the clip which directly affects the receptive field of RNN during training, is further experimented with in Section 5.2." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.357, + 0.892, + 0.433 + ], + "angle": 0, + "content": "While the concept is very simple, its impact on the performance is substantial. By addressing the training-inference discrepancy, the model is able to learn more effectively. Section 5.3 provides further experiments on various weight choices that support the choice of our weights." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.444, + 0.693, + 0.462 + ], + "angle": 0, + "content": "4. Experimental Setup" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.469, + 0.596, + 0.484 + ], + "angle": 0, + "content": "4.1. Dataset" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.492, + 0.892, + 0.553 + ], + "angle": 0, + "content": "Similar to prior works on online action detection, we evaluate MiniROAD on two publicly-available datasets: THUMOS'14 and TVSeries. In addition, we use a large FineAction dataset for performance evaluation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.553, + 0.892, + 0.627 + ], + "angle": 0, + "content": "THUMOS'14 [19] comprises over 20 hours of sports video, e.g. baseball pitch, each annotated with 20 actions. Following the prior works [3, 43], we train on the validation set (200 untrimmed videos) and evaluate on the test set (213 untrimmed videos)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.628, + 0.892, + 0.703 + ], + "angle": 0, + "content": "TVSeries [7] consists of 27 episodes of six popular TV shows, spanning 16 hours. It is annotated with 30 real-life everyday actions like opening doors, running, and drinking. It proposes unique challenges as it has a diverse viewpoint, heavy occlusion, and a large portion of background frames." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.704, + 0.892, + 0.78 + ], + "angle": 0, + "content": "FineAction [24] is a large dataset introduced for Temporal Action Detection with more detailed activity descriptions with varying difficulties. It consists of 16,732 untrimmed videos spanning 705 video hours with 103,324 temporal instances of 106 action categories." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.787, + 0.592, + 0.803 + ], + "angle": 0, + "content": "4.2. Setting" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.81, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Feature Extraction. As the selection of a feature extractor is an important factor that directly affects the performance, we follow the experimental settings of the state-of-the-art methods [43, 3, 40]. For THUMOS and TVSeries, we first sample the videos into 24 FPS and feed non-overlapping snippets to the feature extractor. The snippet" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "10344" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.473, + 0.318 + ], + "angle": 0, + "content": "size is set to 6 and TSN [34] is adopted as the feature extractor. We employ implementation and checkpoints from MMACTION [6] and experiment with feature extractors pretrained on Kinetics-400 [2] and Activitynet1.3 [17]. For FineAction Dataset, we use the officially available features extracted using a Two-Stream architecture [32]. This architecture feeds non-overlapping snippets of 16 RGB or optical flow frames to two separate I3D [2] models that were pretrained with Kinetics. Since the officially available feature is too condensed (16 frames being converted into one feature) and causes overlooking of the fine-grained action instances, we linearly interpolate the temporal resolution of the feature sequence by a factor of four. For all experiments, the visual and motion features are concatenated along the channel dimension before feeding into the model." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.321, + 0.47, + 0.457 + ], + "angle": 0, + "content": "Implementation Details. To substantiate our claim that mitigating the training-inference discrepancy leads to more effective training of RNN models, we adopt a minimalist approach in designing our model. Our model comprises an embedding layer, a GRU, and a classification layer. Despite its simplicity, our model achieves comparable or even better performance to the state-of-the-art methods thanks to maximizing RNN's potential with our proposed methodology, while its lightweight property makes it highly efficient." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.458, + 0.47, + 0.504 + ], + "angle": 0, + "content": "Implementation details can be found in the officially available code. Experiments are conducted using Nvidia RTX3090 Graphics cards." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.514, + 0.263, + 0.53 + ], + "angle": 0, + "content": "4.3. Evaluation Metrics" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.538, + 0.47, + 0.75 + ], + "angle": 0, + "content": "To evaluate the performance of our methodology, we follow prior works and report per-frame mean Average Precision (mAP) on the THUMOS'14 dataset and per-frame mean calibrated Average Precision (mcAP) on the TVSeries dataset. Per-frame mAP is adopted for the FineAction Dataset as well. For measuring mAP, we collect all the classification scores for each frame and calculate the precision and recall based on the sorted results. We then calculate the Average Precision for each class using the precision and recall values and average the results over all classes to obtain the mAP. The mcAP, introduced by [7] with the TVSeries dataset, was proposed to address the imbalance between positive and negative samples. Calibrated average precision (cAP) is calculated using the formula" + }, + { + "type": "equation", + "bbox": [ + 0.176, + 0.761, + 0.47, + 0.797 + ], + "angle": 0, + "content": "\\[\nc A P = \\frac {\\sum_ {i} c P r e c (i) \\cdot I (i)}{\\sum_ {i} I (i)}, \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.807, + 0.47, + 0.838 + ], + "angle": 0, + "content": "where \\( I(i) \\) is 1 if the frame \\( i \\) is a true positive and \\( cPrec \\) is calculated by" + }, + { + "type": "equation", + "bbox": [ + 0.187, + 0.849, + 0.47, + 0.881 + ], + "angle": 0, + "content": "\\[\nc P r e c = \\frac {w \\cdot T P}{w \\cdot T P + F P}. \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.886, + 0.468, + 0.902 + ], + "angle": 0, + "content": "where \\(w\\) is the ratio between negative and positive samples." + }, + { + "type": "table", + "bbox": [ + 0.502, + 0.089, + 0.894, + 0.179 + ], + "angle": 0, + "content": "
MethodBackboneParametersGFLOPsmAP (%)
TRN[39]402.9M1.4662.1
OadTR[36]75.8M2.5465.2
LSTR[40]TSN58.0M7.5369.5
GateHUB[3](Kinetics)45.2M6.9870.7
TeSTra[43]58.9M4.3771.2
MiniROAD (Ours)15.8M0.015871.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.194, + 0.893, + 0.24 + ], + "angle": 0, + "content": "Table 1: Comparison to other recent OAD methods in terms of parameter count, GFLOPs, and mAP on THUMOS'14 dataset using the Kinetics pretrained feature extractor." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.258, + 0.698, + 0.274 + ], + "angle": 0, + "content": "5. Results and Analysis" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.288, + 0.8, + 0.304 + ], + "angle": 0, + "content": "5.1. Comparisons with State of the Art" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.316, + 0.893, + 0.633 + ], + "angle": 0, + "content": "THUMOS'14. Table 1 presents a comparison of MiniROAD with recent methods on THUMOS'14, using features extracted by the Kinetics-pretrained TSN backbone. We measured the parameter count and GFLOPs of TeSTra and ours by ourselves, and the other numbers are from [3]. We can see that MiniROAD outperforms state-of-the-art methods on THUMOS'14 by \\(0.6\\%\\) in mAP while requiring only \\(0.4\\%\\) GFLOPs and \\(27\\%\\) parameters. There is a significant gain in efficiency thanks to the RNN architecture. RNN's advantage in efficiency can be also seen by TRN. Despite its large number of parameters, TRN requires the least number of computations compared to the recent works as recent works employ transformer architecture that needs a lot more computation overhead for calculating attention. These large gains in efficiency suggest that RNNs have a significant advantage in online settings, specifically for those that require real-time processing. To validate the generalization of our method, we also evaluate the same dataset using the feature extractor pretrained with Activitynet. The results are shown in Table 2a and our method achieves the best results in this setting as well." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.639, + 0.892, + 0.714 + ], + "angle": 0, + "content": "TVSeries. Table 2b shows the comparison of our method with the other methods using the features extracted by Kinetics and Activitynet pretrained features. Our method is able to achieve comparable or better performance to the state-of-the-art in this dataset as well." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.895, + 0.9 + ], + "angle": 0, + "content": "FineAction. Table 3 compares the performance of our approach and recent methods on the FineAction Dataset. As we are the first to evaluate this dataset for the OAD task, we reproduced all the results in Table 3 using the publicly available code. Our model outperforms the recent methods, achieving a \\(17\\%\\) performance gain over the next best-performing method. This dataset is much larger and contains activities of varying difficulties, in contrast to previously tested datasets that had limited action instances of similar categories. Thus, it provides a more realistic setting and can serve as a valuable benchmark for future OAD research." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "10345" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.08, + 0.089, + 0.462, + 0.262 + ], + "angle": 0, + "content": "
MethodmAP (%)MethodmcAP (%)
AnetKineticsAnetKinetics
RED [14]45.3-RED[14]79.2-
IDN [12]50.060.3FATS[21]81.784.6
FATS [21]51.659.0IDN[12]84.786.1
TRN [39]47.262.1TRN[39]83.786.2
LAP [29]53.3-TFN[13]85.0-
TFN [13]55.7-LAP[29]85.3-
OadTR [36]58.365.2PKD[42]-86.4
LSTR [40]65.369.5OadTR[36]85.487.2
GateHUB [3]69.170.7LSTR[40]88.189.1
TeSTra [43]68.271.2GateHUB[3]88.489.6
Ours69.371.8Ours88.589.6
" + }, + { + "type": "table_caption", + "bbox": [ + 0.167, + 0.268, + 0.185, + 0.28 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "table_caption", + "bbox": [ + 0.358, + 0.268, + 0.377, + 0.28 + ], + "angle": 0, + "content": "(b)" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.293, + 0.47, + 0.354 + ], + "angle": 0, + "content": "Table 2: Comparison to other OAD methods on (a) THUMOS'14 [19] dataset and (b) TVSeries dataset [7]. Results using the backbone pre-trained using Activitynet [17] and Kinetics [2] are shown." + }, + { + "type": "table", + "bbox": [ + 0.165, + 0.382, + 0.382, + 0.487 + ], + "angle": 0, + "content": "
MethodmAP (%)
OadTR[36]31.8
LSTR[40]31.6
TeSTra[43]31.2
Ours37.1
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.502, + 0.47, + 0.532 + ], + "angle": 0, + "content": "Table 3: Comparison to other OAD methods on FineAction dataset [24]." + }, + { + "type": "image", + "bbox": [ + 0.114, + 0.563, + 0.418, + 0.771 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.784, + 0.47, + 0.875 + ], + "angle": 0, + "content": "Figure 3: Attention heatmap (top) and its specific values (bottom) of the transformer encoders in OadTR [36]. For the heatmap calculation, all the attention values in the encoder (of every layer and head) are collected for the entire test set input which are then averaged out over the heads. The above shows the collected values after normalization." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.091, + 0.808, + 0.108 + ], + "angle": 0, + "content": "5.2. Why is RNN adequate for the task?" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.114, + 0.892, + 0.249 + ], + "angle": 0, + "content": "The prevailing reasoning behind the lower performance of RNNs is that they struggle with learning long-range dependencies. This is often attributed to training difficulties such as gradient vanishing that can arise when processing prolonged sequences. Therefore, recent works have been using transformers for OAD as they are particularly proficient at capturing long-term dependencies. However, it is worth asking how much temporal information is actually needed for OAD." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.256, + 0.893, + 0.483 + ], + "angle": 0, + "content": "What do Transformers Actually See? Inspired by the recent success of transformer models in OAD, we analyzed the attention weights within the transformer multi-head attention to gain insights into the model's decision-making process. The visualization results are presented in Figure 3. As evident from the heat map and the graph, the transformer model predominantly focuses on the recent and neighboring frames, indicating the recent input's dominant influence on the prediction. Surprisingly, despite the transformer's intended capability of capturing long-term dependencies, the model mainly relies on the recent frames for making the current frame prediction. Our analysis reinforces the argument that RNN's inductive bias, which prioritizes the current input while retaining meaningful temporal information from the past, is well suited for the task." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.49, + 0.893, + 0.747 + ], + "angle": 0, + "content": "Optimal Length of Temporal Information. Figure 4 shows the performance of our model with varying clip lengths using the proposed methodology. As our methodology trains the model with the loss computed at the end of the clip, the graph shows the trade-off between providing more temporal information and ignoring the supervision of the earlier steps. The figure shows that a saturation point is reached at 32 seconds and providing more information than 32 seconds does not improve the performance. To the commonly held belief that the RNN does not benefit from prolonged sequence length, there exists a model's maximum capacity. It is important to note, however, that RNN's capacity is already enough to perform well on the OAD task, validated by the promising performances shown in Section 5.1. A slight drop in performance after 32 seconds is a result of RNN not being able to use temporal information beyond a certain point and much supervision lost during training." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.757, + 0.75, + 0.773 + ], + "angle": 0, + "content": "5.3. What is the optimal weight?" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.781, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Our work shows that the uniform weights put on computed loss at each time-step hinders the effective training of the RNNs. To make the most use of the finding, we experimented with varying weight choices \\(\\alpha_{t}\\) in (1) at each time step. Different choices of weights including uniform, linearly increasing, exponentially increasing, learnable, and step function, are experimented. The results are shown in Table 4a. The results indicate that assigning uniform" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "10346" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.128, + 0.092, + 0.427, + 0.106 + ], + "angle": 0, + "content": "Effect of Hidden State Duration on THUMOS 14" + }, + { + "type": "image", + "bbox": [ + 0.108, + 0.117, + 0.418, + 0.288 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.302, + 0.47, + 0.333 + ], + "angle": 0, + "content": "Figure 4: Effect of varying the length of the clip \\( L \\) during training." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.361, + 0.473, + 0.68 + ], + "angle": 0, + "content": "weights to the loss computed at each time-step results in the worst performance, which is consistent with the findings discussed in the paper that this conventional approach impedes the effective training of the model. Applying linearly increasing weights performs better than assigning uniform weights because it places less emphasis on early-stage predictions. The next best performing choice is exponentially increasing weights, which heavily emphasizes the loss computed at later stages. The next best performing weight choice is learnable weights. For this experimental setup, learnable embeddings of size \\( L \\) (length of the clip) were trained. When computing the loss, we apply softmax activation to the learnable weights, which are then multiplied by their corresponding loss at their time steps. This approach shows even better performance than exponentially increasing weights. The best-performing choice of weight is step-function which uses only the loss computed at the end. This results in the best performance as the loss associated with predictions using the informative hidden state best resemble the dominant predictions made at the inference stage." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.706, + 0.325, + 0.721 + ], + "angle": 0, + "content": "5.4. Effectiveness of the method" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Table 4b shows the result of our model with and without the proposed non-uniform weights. We can observe that there is a \\(5\\%\\) mAP increase by using our proposed methodology. In addition, we also experiment with our proposed methodology using the transformer architecture. For the experiment, we adopt the transformer encoder from OadTR and set the encoding layers to 3 and the number of heads to 8 which is the default setting in the publicly available code. We observe that the performance increases from 63.0 to \\(64.9\\%\\) mAP with a \\(1.9\\%\\) mAP increase using our proposed methodology." + }, + { + "type": "table", + "bbox": [ + 0.503, + 0.09, + 0.691, + 0.183 + ], + "angle": 0, + "content": "
Weight TypemAP (%)
Uniform66.4
Linear68.6
Exponential69.8
Learnable70.8
Step-Function71.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.587, + 0.19, + 0.608, + 0.203 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "table", + "bbox": [ + 0.693, + 0.102, + 0.894, + 0.171 + ], + "angle": 0, + "content": "
Method
TransformerMiniROAD
Uniform Weight63.066.4
Proposed64.971.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.782, + 0.19, + 0.802, + 0.202 + ], + "angle": 0, + "content": "(b)" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.216, + 0.894, + 0.291 + ], + "angle": 0, + "content": "Table 4: (a) Result of applying different weights \\(\\alpha_{t}\\) in (1). Otherwise stated, Step-Function is the default choice in our paper which only uses the loss computed at the end of the clip. (b) Result of applying the proposed weights on the transformer-based model and on our model." + }, + { + "type": "table", + "bbox": [ + 0.502, + 0.308, + 0.892, + 0.421 + ], + "angle": 0, + "content": "
MethodOF. Comp.RGB Feat.OF. Feat.Model FPSOverall FPSmAP (%)
TRN14320.562.1
OadTR14520.565.2
LSTR28.838321918721.269.5
TeSTra16920.971.2
Ours3730023.871.8
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.436, + 0.893, + 0.513 + ], + "angle": 0, + "content": "Table 5: Runtime Comparison of OAD methods on THU-MOS'14 dataset with flow features extracted using TV-L1 [41] algorithm. OF. Comp., RGB Feat., and OF. Feat. are the speed of extracting optical flows, rgb features, and optical flow features respectively, measured in FPS." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.531, + 0.605, + 0.545 + ], + "angle": 0, + "content": "5.5. Runtime" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.555, + 0.892, + 0.873 + ], + "angle": 0, + "content": "Efficiency is a critical aspect of the online nature of the OAD task. To assess efficiency, we compare MiniROAD's runtime with recent methods in frames per second (FPS) using videos from the THUMOS'14 dataset on a system with a single RTX3090 GPU. The results in Table 5 demonstrate that our model's lightweight RNN architecture is very efficient, running about 200 times faster than previous methods. However, it is worth noting that the model's speed is not the final speed, as the input of the OAD model requires the extraction of visual and motion features. As illustrated in Table 5, computing optical flow accounts for the majority of the computation time. The end-to-end speed, which encompasses the speed after computing optical flows, extracting visual and motion features, and passing through the model, is reported as Overall FPS in the table. Although extracting optical flow acts as a bottleneck, the efficiency of our model yields 2.9 gains in FPS overall. These gains in overall speed are further improved when a faster optical flow computing algorithm is used. To demonstrate the efficacy of this approach, we also test using the NVIDIA Optical Flow \\(\\mathrm{SDK}^1\\) (NVOFA) for faster optical flow computa" + }, + { + "type": "page_footnote", + "bbox": [ + 0.518, + 0.887, + 0.761, + 0.9 + ], + "angle": 0, + "content": "1https://developer.nvidia.com/opticalflow-sdk" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "10347" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.134, + 0.089, + 0.835, + 0.291 + ], + "angle": 0, + "content": "
MethodPre-TrainmAP@τ0Average
0.250.50.7511.251.51.752
RED [14]45.342.139.637.535.834.433.232.137.5
TRN [39]45.142.440.739.137.736.435.334.338.9
TTM [35]45.943.742.441.039.939.437.937.340.9
LAP-Net [29]49.047.445.343.241.339.738.337.042.6
OadTR [36]ANet1.350.249.348.146.845.343.942.441.145.9
LSTR [40]--------50.1
GateHUB [3]--------54.2
TeSTra [43]64.761.858.755.753.251.149.247.855.3
Ours65.463.360.557.454.851.949.747.756.3
TTM [35]46.845.544.643.641.941.140.438.742.8
LSTR [36]60.458.656.053.350.948.947.145.752.6
OadTR [36]K40059.858.556.654.652.650.548.646.853.5
TeSTra [43]66.263.560.557.454.852.650.548.956.8
Ours68.566.363.560.757.955.653.551.459.7
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.305, + 0.893, + 0.336 + ], + "angle": 0, + "content": "Table 6: Action Anticipation Results on THUMOS'14 dataset with feature extractor pretrained with Activitynet (top) and Kinetics (bottom)." + }, + { + "type": "table", + "bbox": [ + 0.079, + 0.348, + 0.47, + 0.461 + ], + "angle": 0, + "content": "
MethodOF. Comp.RGB Feat.OF. Feat.Model FPSOverall FPSmAP (%)
TRN†14366.061.6
OADTR†14566.363.3
LSTR†1K38321918773.867.1
TeSTra16970.967.3
Ours3730012268.4
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.476, + 0.47, + 0.536 + ], + "angle": 0, + "content": "Table 7: Comparison to other OAD methods on THU-MOS'14 dataset with flow features extracted using NVIDIA OPTICAL FLOW. \\(\\dagger\\) was reproduced by us. All the values indicate the speed measured in FPS." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.552, + 0.47, + 0.718 + ], + "angle": 0, + "content": "tion, which runs at around 1K FPS. By utilizing the faster flow algorithm, our model runs at 122 FPS which is 1.72 times faster than the state-of-the-art model. Although there is a degradation in the final performance compared to the traditionally used flow algorithm, this highlights the availability of an alternative approach that can deliver faster end-to-end speed while balancing performance and speed trade-offs. The significant increase in end-to-end speed when using the faster optical flow algorithm indicates that additional increases can be gained with RGB-only inputs, leaving open opportunities for future work." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.727, + 0.265, + 0.743 + ], + "angle": 0, + "content": "5.6. Action Anticipation" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.471, + 0.903 + ], + "angle": 0, + "content": "As our methodology is also applicable to other online tasks, we extend our method to Action Anticipation, which is a task of anticipating upcoming actions using the histories. Instead of predicting the current time frame, the model is trained to predict the next upcoming actions every 0.25 seconds up to 2 seconds. Table 6 shows the results of predictions at each of that time-step. It shows that our method performs favorably to the other methods with \\(1\\%\\) mAP gain using activitynet pretrained backbone and \\(2.9\\%\\) mAP gain using kinetics pretrained backbone over the previous state" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.352, + 0.892, + 0.397 + ], + "angle": 0, + "content": "of-the-art. While our methodology was initially designed for OAD, its applicability extends beyond OAD and can be used for other similar tasks." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.412, + 0.619, + 0.427 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.438, + 0.892, + 0.603 + ], + "angle": 0, + "content": "We revisit RNN for online action detection and show its potential in dealing with the task. We identify the training-inference discrepancy as a primary cause of the lower performance of RNNs and address the issue by introducing non-uniform weights to the loss computed at each timesteps. We demonstrate the effectiveness of our proposed method using MiniROAD, a minimal RNN-based OAD model. MiniROAD achieves equal or better accuracy than the existing best method on challenging datasets, with a significant increase in efficiency. With the faster NVOFA, MiniROAD runs at an impressive 122 FPS." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.604, + 0.892, + 0.71 + ], + "angle": 0, + "content": "We note that recent OAD methods rely heavily on optical flows, which impede end-to-end speed. While faster optical flow algorithms like NVOFA can mitigate this issue, flow-free OAD remains an open yet challenging problem. By highlighting the suitability of RNNs for processing streaming videos, we hope to pave the way for further advancements and shed light on developing more efficient models." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.725, + 0.667, + 0.741 + ], + "angle": 0, + "content": "Acknowledgements" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.892, + 0.902 + ], + "angle": 0, + "content": "This work was supported by Samsung Electronics Co., Ltd. (Mobile eXperience Business), Yonsei University Artificial Intelligence Graduate School Program under Grant 2020-0-01361, and by the Institute of Information & communications Technology Planning & Evaluation (IITP) grant funded by the Korea government(MSIT) (No.2022-0-00124, Development of Artificial Intelligence Technology for Self-Improving Competency-Aware Learning Capabilities). The work of Joungbin was in part supported by the Hyundai Motor Chung Mong-Koo Foundation." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "10348" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.47, + 0.171 + ], + "angle": 0, + "content": "[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lučić, and Cordelia Schmid. Vivit: A video vision transformer. In IEEE International Conference on Computer Vision (ICCV), pages 6836-6846, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.173, + 0.471, + 0.228 + ], + "angle": 0, + "content": "[2] Joao Carreira and Andrew Zisserman. Quo vadis, action recognition? a new model and the kinetics dataset. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 6299-6308, 2017. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.23, + 0.471, + 0.299 + ], + "angle": 0, + "content": "[3] Junwen Chen, Gaurav Mittal, Ye Yu, Yu Kong, and Mei Chen. Gatehub: Gated history unit with background suppression for online action detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 3, 4, 5, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.301, + 0.471, + 0.37 + ], + "angle": 0, + "content": "[4] Kyunghyun Cho, Bart Van Merrienboer, Caglar Gulcehre, Dzmitry Bahdanau, Fethi Bougares, Holger Schwenk, and Yoshua Bengio. Learning phrase representations using rnn encoder-decoder for statistical machine translation. arXiv preprint arXiv:1406.1078, 2014. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.372, + 0.471, + 0.427 + ], + "angle": 0, + "content": "[5] Junyoung Chung, Caglar Gulcehre, KyungHyun Cho, and Yoshua Bengio. Empirical evaluation of gated recurrent neural networks on sequence modeling. arXiv preprint arXiv:1412.3555, 2014. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.429, + 0.471, + 0.471 + ], + "angle": 0, + "content": "[6] MMAction2 Contributors. Openmmlab's next generation video understanding toolbox and benchmark. https://github.com/open-mmlab/mmaction2, 2020.5" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.473, + 0.471, + 0.528 + ], + "angle": 0, + "content": "[7] Roeland De Geest, Efstratios Gavves, Amir Ghodrati, Zhenyang Li, Cees Snoek, and Tinne Tuytelaars. Online action detection. In European Conference on Computer Vision (ECCV), pages 269-284. Springer, 2016. 1, 2, 4, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.53, + 0.471, + 0.585 + ], + "angle": 0, + "content": "[8] Roeland De Geest and Tinne Tuytelaars. Modeling temporal structure with lstm for online action detection. In IEEE Winter Conference on Applications of Computer Vision (WACV), pages 1549-1557. IEEE, 2018. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.587, + 0.471, + 0.642 + ], + "angle": 0, + "content": "[9] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. arXiv preprint arXiv:1810.04805, 2018. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.644, + 0.47, + 0.727 + ], + "angle": 0, + "content": "[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.729, + 0.47, + 0.756 + ], + "angle": 0, + "content": "[11] Jeffrey L Elman. Finding structure in time. Cognitive science, 14(2):179-211, 1990. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.758, + 0.47, + 0.814 + ], + "angle": 0, + "content": "[12] Hyunjun Eun, Jinyoung Moon, Jongyoul Park, Chanho Jung, and Changick Kim. Learning to discriminate information for online action detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2020. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.816, + 0.47, + 0.857 + ], + "angle": 0, + "content": "[13] Hyunjun Eun, Jinyoung Moon, Jongyoul Park, Chanho Jung, and Changick Kim. Temporal filtering networks for online action detection. Pattern Recognition, 111:107695, 2021. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.859, + 0.47, + 0.901 + ], + "angle": 0, + "content": "[14] Jiyang Gao, Zhenheng Yang, and Ram Nevatia. Red: Reinforced encoder-decoder networks for action anticipation. arXiv preprint arXiv:1707.04818, 2017. 2, 6, 8" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.161 + ], + "angle": 0, + "content": "[15] Mingfei Gao, Yingbo Zhou, Ran Xu, Richard Socher, and Caiming Xiong. Woad: Weakly supervised online action detection in untrimmed videos. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1915-1923, 2021. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.164, + 0.892, + 0.205 + ], + "angle": 0, + "content": "[16] Albert Gu, Karan Goel, and Christopher Ré. Efficiently modeling long sequences with structured state spaces. arXiv preprint arXiv:2111.00396, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.207, + 0.892, + 0.275 + ], + "angle": 0, + "content": "[17] Fabian Caba Heilbron, Victor Escorcia, Bernard Ghanem, and Juan Carlos Niebles. Activitynet: A large-scale video benchmark for human activity understanding. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 961-970. IEEE, 2015. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.278, + 0.892, + 0.316 + ], + "angle": 0, + "content": "[18] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 9(8):1735-1780, 1997. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.32, + 0.892, + 0.388 + ], + "angle": 0, + "content": "[19] Haroon Idrees, Amir R Zamir, Yu-Gang Jiang, Alex Gorban, Ivan Laptev, Rahul Sukthankar, and Mubarak Shah. The thumos challenge on action recognition for videos \"in the wild\". Computer Vision and Image Understanding(CVIU), 155:1-23, 2017. 4, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.391, + 0.892, + 0.459 + ], + "angle": 0, + "content": "[20] Jinkyu Kim, Teruhisa Misu, Yi-Ting Chen, Ashish Tawari, and John Canny. Grounding human-to-vehicle advice for self-driving vehicles. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 10591–10599, 2019. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.462, + 0.892, + 0.515 + ], + "angle": 0, + "content": "[21] Young Hwi Kim, Seonghyeon Nam, and Seon Joo Kim. Temporally smooth online action detection using cycle-consistent future anticipation. Pattern Recognition, 116:107954, 2021. 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.518, + 0.892, + 0.573 + ], + "angle": 0, + "content": "[22] Serkan Kiranyaz, Onur Avci, Osama Abdeljaber, Turker Ince, Moncef Gabbouj, and Daniel J Inman. 1d convolutional neural networks and applications: A survey. Mechanical systems and signal processing, 151:107398, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.576, + 0.892, + 0.617 + ], + "angle": 0, + "content": "[23] Zachary C Lipton, John Berkowitz, and Charles Elkan. A critical review of recurrent neural networks for sequence learning. arXiv preprint arXiv:1506.00019, 2015. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.619, + 0.892, + 0.672 + ], + "angle": 0, + "content": "[24] Yi Liu, Limin Wang, Yali Wang, Xiao Ma, and Yu Qiao. Fineaction: A fine-grained video dataset for temporal action localization. IEEE Transactions on Image Processing, 2022, 4, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.676, + 0.892, + 0.731 + ], + "angle": 0, + "content": "[25] Antonio Orvieto, Samuel L Smith, Albert Gu, Anushan Fernando, Caglar Gulcehre, Razvan Pascanu, and Soham De. Resurrecting recurrent neural networks for long sequences. arXiv preprint arXiv:2303.06349, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.733, + 0.892, + 0.8 + ], + "angle": 0, + "content": "[26] Guansong Pang, Cheng Yan, Chunhua Shen, Anton van den Hengel, and Xiao Bai. Self-trained deep ordinal regression for end-to-end video anomaly detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 12173-12182, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.802, + 0.892, + 0.857 + ], + "angle": 0, + "content": "[27] Hyunjong Park, Jongyoun Noh, and Bumsub Ham. Learning memory-guided normality for anomaly detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 14372-14381, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.859, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[28] Bo Peng, Eric Alcaide, Quentin Anthony, Alon Albalak, Samuel Arcadinho, Huanqi Cao, Xin Cheng, Michael Chung, Matteo Grella, Kranthi Kiran GV, et al. Rwkv:" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "10349" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.108, + 0.092, + 0.47, + 0.12 + ], + "angle": 0, + "content": "Reinventing rnns for the transformer era. arXiv preprint arXiv:2305.13048, 2023. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.123, + 0.47, + 0.178 + ], + "angle": 0, + "content": "[29] Sanqing Qu, Guang Chen, Dan Xu, Jinhu Dong, Fan Lu, and Alois Knoll. Lap-net: Adaptive features sampling via learning action progression for online action detection. arXiv preprint arXiv:2011.07915, 2020. 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.181, + 0.469, + 0.221 + ], + "angle": 0, + "content": "[30] Mike Schuster and Kuldip K Paliwal. Bidirectional recurrent neural networks. IEEE transactions on Signal Processing, 45(11):2673-2681, 1997. 1, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.225, + 0.469, + 0.293 + ], + "angle": 0, + "content": "[31] Tianmin Shu, Dan Xie, Brandon Rothrock, Sinisa Todorovic, and Song Chun Zhu. Joint inference of groups, events and human roles in aerial videos. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 4576-4584, 2015. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.297, + 0.469, + 0.351 + ], + "angle": 0, + "content": "[32] Karen Simonyan and Andrew Zisserman. Two-stream convolutional networks for action recognition in videos. Conference on Neural Information Processing Systems (NeurIPS), 27, 2014. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.355, + 0.469, + 0.41 + ], + "angle": 0, + "content": "[33] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Conference on Neural Information Processing Systems (NeurIPS), 30, 2017. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.413, + 0.469, + 0.481 + ], + "angle": 0, + "content": "[34] Limin Wang, Yuanjun Xiong, Zhe Wang, Yu Qiao, Dahua Lin, Xiaou Tang, and Luc Van Gool. Temporal segment networks: Towards good practices for deep action recognition. In European Conference on Computer Vision (ECCV), pages 20-36. Springer, 2016. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.485, + 0.469, + 0.538 + ], + "angle": 0, + "content": "[35] Wen Wang, Xiaojiang Peng, Yanzhou Su, Yu Qiao, and Jian Cheng. Tpp: Temporal transformer with progressive prediction for efficient action anticipation. Neurocomputing, 438:270-279, 2021. 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.542, + 0.469, + 0.598 + ], + "angle": 0, + "content": "[36] Xiang Wang, Shiwei Zhang, Zhiwu Qing, Yuanjie Shao, Zhengrong Zuo, Changxin Gao, and Nong Sang. Oadtr: Online action detection with transformers. IEEE International Conference on Computer Vision (ICCV), 2021. 2, 5, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.601, + 0.469, + 0.64 + ], + "angle": 0, + "content": "[37] Paul J Werbos. Backpropagation through time: what it does and how to do it. Proceedings of the IEEE, 78(10):1550-1560, 1990. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.644, + 0.469, + 0.727 + ], + "angle": 0, + "content": "[38] Chao-Yuan Wu, Yanghao Li, Karttikeya Mangalam, Haoqi Fan, Bo Xiong, Jitendra Malik, and Christoph Feichtenhofer. Memvit: Memory-augmented multiscale vision transformer for efficient long-term video recognition. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 13587-13597, 2022. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.73, + 0.469, + 0.785 + ], + "angle": 0, + "content": "[39] Mingze Xu, Mingfei Gao, Yi-Ting Chen, Larry S. Davis, and David J. Crandall. Temporal recurrent networks for online action detection. In IEEE International Conference on Computer Vision (ICCV), 2019. 2, 5, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.788, + 0.469, + 0.855 + ], + "angle": 0, + "content": "[40] Mingze Xu, Yuanjun Xiong, Hao Chen, Xinyu Li, Wei Xia, Zhuowen Tu, and Stefano Soatto. Long short-term transformer for online action detection. In Conference on Neural Information Processing Systems (NeurIPS), 2021. 2, 4, 5, 6, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.859, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[41] Christopher Zach, Thomas Pock, and Horst Bischof. A duality based approach for realtime tv-l 1 optical flow. In Pattern Recognition, pages 214-223. Springer, 2007. 7" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[42] Peisen Zhao, Lingxi Xie, Ya Zhang, Yanfeng Wang, and Qi Tian. Privileged knowledge distillation for online action detection. arXiv preprint arXiv:2011.09158, 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.136, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[43] Yue Zhao and Philipp Krahenbuhl. Real-time online video detection with temporal smoothing transformers. In European Conference on Computer Vision (ECCV), 2022. 3, 4, 5, 6, 8" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.19 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "10350" + } + ] +] \ No newline at end of file diff --git a/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/ea56ef7d-d0ee-4b4c-86bd-22698b72c0f8_origin.pdf b/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/ea56ef7d-d0ee-4b4c-86bd-22698b72c0f8_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..4cc436272a75d8ab6eae3655680a755b2f42abdb --- /dev/null +++ b/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/ea56ef7d-d0ee-4b4c-86bd-22698b72c0f8_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:f487f57fb0a66e72f40bbda7cb2410c6f776ec422b426e72b98931edfa189c7c +size 505876 diff --git a/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/full.md b/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/full.md new file mode 100644 index 0000000000000000000000000000000000000000..70eab0d355d1f05767e8bbced4e30abfaa8cad69 --- /dev/null +++ b/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/full.md @@ -0,0 +1,273 @@ +# MiniROAD: Minimal RNN Framework for Online Action Detection + +Joungbin An $^{1}$ Hyolim Kang $^{1}$ Su Ho Han $^{1}$ Ming-Hsuan Yang $^{1,2,3}$ Seon Joo Kim $^{1}$ $^{1}$ Yonsei University $^{2}$ UC Merced $^{3}$ Google Research + +# Abstract + +Online Action Detection (OAD) is the task of identifying actions in streaming videos without access to future frames. Much effort has been devoted to effectively capturing long-range dependencies, with transformers receiving the spotlight for their ability to capture long-range temporal structures. In contrast, RNNs have received less attention lately, due to their lower performance compared to recent methods that utilize transformers. In this paper, we investigate the underlying reasons for the inferior performance of RNNs compared to transformer-based algorithms. Our findings indicate that the discrepancy between training and inference is the primary hindrance to the effective training of RNNs. To address this, we propose applying non-uniform weights to the loss computed at each time step, which allows the RNN model to learn from the predictions made in an environment that better resembles the inference stage. Extensive experiments on three benchmark datasets, THU-MOS, TVSeries, and FineAction demonstrate that a minimal RNN-based model trained with the proposed methodology performs equally or better than the existing best methods with a significant increase in efficiency. The code is available at https://github.com/jbistanbul/MiniROAD. + +# 1. Introduction + +Online Action Detection (OAD) is a challenging task that involves identifying actions taking place in a streaming video without access to future frames. Since its introduction [7], OAD has gained great attention in research circles, as it has numerous real-world applications, such as autonomous driving [20], smart surveillance systems [26, 27], and anomaly detection [31]. These applications require the ability to process streaming videos in real-time, making OAD an essential component of many advanced systems. As a result, there has been a growing interest in developing more accurate and efficient methods for performing OAD. + +To address the challenges of OAD, recent efforts have focused on developing novel models for analyzing streaming videos in real-time. The conventional process of OAD consists of two stages. In the first stage, frames are con + +![](images/4e46ec5a3f87f4a85b8ba9bc6e9b9c937b50a833faf5ba68ef3179f3e503bed4.jpg) +Figure 1: Performance of recent OAD methods with respect to GFLOPs and the model's size. + +verted into a sequence of features by a feature extractor. In the second stage, the extracted features are processed to capture the temporal information required for performing OAD. Much attention on OAD research has been paid to this second stage where the two mainstream models are RNNs [11, 30, 18, 5] and Transformers [9, 10, 33]. + +Each model has its strengths and weaknesses. RNNs can capture temporal transitions effectively by modeling sequences recurrently but are known for their training difficulties [23, 30]. Transformers can capture long-term dependencies through self-attention, however, attention computation is computationally expensive. Although recent research has shifted towards using Transformer models, our paper revisits RNN, which has been overlooked in recent studies. + +In this work, we show that RNN's intrinsic inductive bias—prioritizing the current input while preserving meaningful temporal information from the histories—makes them well-suited for OAD. Unlike in natural language processing, where a distant word can significantly affect the next sequence prediction, we observe that in OAD, the current and its neighboring frames have a dominant influence on the current prediction. In addition, RNN is efficient, as it requires a small computational overhead compared to + +the transformer models, making them well-suited for online tasks that require running in real-time. + +Despite its architecture being well-suited for the OAD task, RNN has been recently overlooked due to the promising results shown by transformer-based models. The prevailing reasoning behind the lower performance of RNN based method was the difficulty of learning long-range dependencies [37, 23]. In this paper, we find that it is the training-inference discrepancy that hinders the effective training of RNNs. + +During inference, the video is processed frame-by-frame in a streaming fashion. During training, however, the video is divided into multiple clips, which are then fed to the model, as illustrated in Figure 2. This creates a significant discrepancy between the two phases since videos are usually much longer than the training clips. Consequently, the clips provide limited temporal information, leading to a restricted view of the video during training. This limitation is not as problematic for recent OAD models using transformers as it is for models using RNNs. This is because recent transformer models utilize the temporal information between clips using explicit long-term memory even during training. At the same time, RNNs do not since they receive a non-informative hidden state initialized as zero at the beginning of the clip. As a result, RNNs make most predictions during training with the hidden state that lacks temporal information, whereas it makes most predictions during inference with the hidden state accumulated with sufficient temporal information. + +We demonstrate that addressing the training and inference discrepancy in RNNs alone can significantly improve their performance without requiring any changes to their architecture. Specifically, we find that introducing nonuniform weights to losses at different time steps can alleviate this discrepancy, which is a primary factor contributing to RNN's suboptimal performance. This approach differs from the conventional assumption of averaging the loss over the joint prediction, as we demonstrate that non-uniform weights to the loss are essential for effectively training the model. We demonstrate the effectiveness of our methodology using Minimal Recurrent neural network for Online Action Detection (MiniROAD), which is a lightweight GRU based model. Figure 1 shows the comparison of our model with other recent models in terms of the model's performance, GFLOPs, and size. It shows that our method with only $\sim 0.4\%$ computational power needed for the previous state-of-the-art, is able to achieve better performance. + +Our model is evaluated on conventional OAD benchmark datasets, including THUMOS'14 and TVSeries, as well as on the recently introduced FineAction dataset. As conventional datasets used for benchmarking OAD tasks are relatively small, the much larger FineAction dataset offers + +a more challenging testbed that better depicts real-life scenarios. Larger datasets like FineAction open up more possibilities for future work on OAD and hence our results can serve as a strong baseline. Our experiments show that our proposed methodologies achieve on-par or better results on the benchmarked dataset with significant improvements in efficiency. + +The main contributions of this work are: + +- We revisit the potential of RNNs and identify the training-inference discrepancy as a primary cause of their lower performance. To address this issue, we propose a simple yet effective method that makes RNN both effective and efficient in capturing the essential temporal information for online action detection. +- Extensive experimental results show that the proposed method performs favorably against the state-of-the-art with high efficiency; our model with only $\sim 0.4\%$ computational overhead compared to the existing methods, achieves on par or better performance on a challenging benchmark dataset, with $\sim 17\%$ performance improvement over the state-of-the-art in a large-scale dataset. +- We expand our methodology and carry out performance evaluation on Action Anticipation and show the applicability of our method on other online tasks. + +# 2. Related Work + +# 2.1. Online Action Detection + +The Online Action Detection task [7] involves detecting actions in the current frame online, using information from the past up to the present. Earlier approaches to Online Action Detection relied on recurrent models. Geest et al. propose a two-stream feedback network [8], utilizing LSTM [18] where one stream focuses on feature representation and the other on temporal patterns. RED [14] takes advantage of reinforcement learning to make action predictions as early as possible. Recent works using RNNs focus on designing more effective RNN cells. TRN [39] models a greater temporal context by having the LSTM cell [18] anticipate the future. IDN [12] uses the GRU cell [4] to explicitly differentiate relevant information for ongoing actions. In [21], FATSnet employs GRU to perform future anticipation and temporal smoothing for more effective current prediction. On the other hand, WOAD [15] introduces a method for weakly supervised online action detection. Existing RNN-based models mainly concentrate on developing more powerful RNN architectures to handle the task. + +Transformers have also been used for the OAD task. OadTR [36] introduces a transformer encoder-decoder architecture for capturing long-term relations through self-attention. In [40], LSTR achieves significant performance improvements by employing a two-stage memory compres + +![](images/4d0ae3b1f4473b1a80ada65e4806ee0f0cf3396eb661b01f31bac37af0b86b4f.jpg) +Figure 2: Illustration of Training and Inference Discrepancy. During the inference stage (top), frames are fed to the model sequentially in a streaming fashion. The hidden state evolves across the entire video, progressively incorporating accumulated temporal context (depicted as darkening over time). In the training stage (bottom), the video is divided into shorter clips of length $L$ , serving as model inputs. Here, the model solely relies on temporal information within each clip, lacking inter-clip associations. This yields dominant predictions constrained by clip-specific information. + +sion design with transformers, allowing for capturing long-term temporal and short-term context through self-attention. This two-stage memory design has been further advanced in subsequent works. GateHUB [3] improves the two-stage architecture with a Gated History Unit to address the limitations of prior cross-attention methods. This avoids incorrect current frame predictions by appropriately weighting informative and uninformative frames. Recently, TeSTra [43] extends the LSTR architecture by introducing two temporal smoothing kernels to reduce inference computation cost. + +Although these transformer models have achieved state-of-the-art results, the attention computation involved in encoding long-term and short-term memory is computationally expensive. In this work, we show that RNNs, without modifying the internals of the architecture, can be just as effective in processing streaming videos with the proposed methodology alone. + +# 2.2. Sequence Modeling + +As many real-world applications involve processing time-series data, sequential modeling has been a topic of ongoing research. Recurrent Neural Networks (RNNs) are one of the most commonly used models for sequence modeling, with popular variants including [18] and [5]. These variants introduce mechanisms within the RNN cell to improve its memory capacity while attending to important parts of the sequential data. 1D CNNs [22] incorporate convolution operations to capture the temporal structure of time-series data. Recent advances have been made using transformers [33] that incorporate attention mechanisms for capturing short and long-term dependencies. Ever since its success in the language domain, its use has been widespread in various fields [10, 9, 1, 38]. + +There have been ongoing efforts on exploring non-transformer architectures. Gu et al. [16] introduces the State Space Model (SSM) in tackling sequence data, proving its efficacy in effectively handling long sequences. A recent work [25] demonstrates that RNNs can match the performance and training speed of SSMs by applying techniques such as linearizing and diagonalizing the recurrence, along with better parameterizations and initializations. Recently, there has been a notable surge in interest surrounding a novel variant of RNN called RWKV [28]. This architecture is the first non-transformer model to be successfully scaled to tens of billions of parameters, bringing together the efficient parallelizable training of transformers with the inference efficiency of RNNs. Our research aligns with these works in resurrecting RNNs in the transformer era. + +# 3. Methodology + +Provided a live streaming video, our objective is to recognize actions in the current frame based on past observations up to the current time. Since $v_{1}^{t}$ , a streaming video from the start until the current time $t$ only provides observations $\{v_{1},\dots,v_{t}\}$ for the past $t$ frames, it is not possible to access any information beyond $v_{t}$ . In this setting, the task is to use $v_{1}^{t}$ to predict $\hat{y}_t \in \{0,1,\dots,K\}$ where $K$ is the number of action classes and index 0 is the background class. During training, the video is divided into clips, each of length $L$ , and hence clips of $v_{t - L}^{t}$ are given as input. Following the convention, we suppose that a pre-trained feature extractor is available which can convert each frame $v_{t}$ into a feature vector $f_{t} \in \mathbb{R}^{C}$ . Our method employs the feature vector $f_{t}$ as the input at current time $t$ to predict $\hat{y}_t$ . + +# 3.1. Overview + +Our method is developed based on the observation that a discrepancy exists between the training and the inference stages, which hinders the effective training of sequence-to-sequence models. Figure 2 illustrates this training-inference discrepancy in more detail. While during inference the model receives temporal information from the beginning of the video to the current time step $t$ , in training, the model is provided with temporal information from $t - L$ to $t$ . Consequently, for each video, clips make predictions using the hidden state that lacks temporal information, which critically affects the losses associated with the early predictions. However, we observe that the conventional approach unknowingly assigns the same uniform weight to all losses for each time step. Our proposed method applies different weights to losses at different time steps, resulting in better training convergence and improved model performance. + +# 3.2. Alleviating Training-Inference Discrepancy + +The conventional loss calculation for OAD follows the following cross-entropy calculation: + +$$ +- \sum_ {t = 1} ^ {L} \sum_ {k = 0} ^ {K} \alpha_ {t} \hat {y} _ {t, k} \log \left(\hat {s} _ {t, k}\right), \tag {1} +$$ + +where $\hat{y}_{t,k}$ and $\hat{s}_{t,k}$ represent the ground truth and predicted logit at time $t$ , $\alpha_{t} \in \{\alpha_{1}, \alpha_{2}, \dots, \alpha_{L}\}$ is the weight applied to the loss at each time step, and $K$ and $L$ are the number of classes and the length of the clip, respectively. We pay attention to the fact that the conventional approach has been unknowingly setting the weight $\alpha_{t}$ uniformly for every time-step in the clip, resulting in $\alpha_{t} = 1 / L$ . However, we show that setting weights uniformly like this, equivalent to using the joint prediction of all time steps, hinders the RNN from being effectively trained as it does not resemble the inference stage. + +Our goal is to alleviate the problem caused by the discrepancy between the training and inference stages. To do so, we first pay careful attention to what is happening in the inference stage where RNN's temporal capacity plays an important role. During the inference stage, temporal information can accumulate as much as the length of the whole video. Although sequence-to-sequence modeling, in theory, can have an unlimited continuous context length, it is known to have a limited temporal capacity [30], the maximum amount of information in which the RNN can retain. For the task of handling streaming videos, as the videos are long, most predictions are made utilizing the information within its limited capacity. This means that RNN uses the temporal information within RNN's temporal capacity for most predictions during inference. + +Selected Weights. From the above reasons, we choose to apply the weights that enable the RNN to utilize its maxi- + +mum temporal capacity. The weight $\alpha_{t}$ is set as: + +$$ +\alpha_ {t} = \left\{ \begin{array}{l l} 1 & \text {i f} t = L \\ 0 & \text {O t h e r w i s e} \end{array} , \right. \tag {2} +$$ + +which is a step function that equals putting masks on all the loss except for the loss at the very last time step in the clip. Applying weights like this during training allows us to 1) disregard the dominant predictions made by using an uninformative hidden state and 2) train the RNN using predictions made by the RNN's sufficient temporal capacity, both of which better reflect the inference stage. As long as the length of the clip $L$ is reasonable enough to exploit RNN's full potential, the prediction made at the end of the clip is more representative of what is actually happening in the inference stage. The choice of $L$ , the length of the clip which directly affects the receptive field of RNN during training, is further experimented with in Section 5.2. + +While the concept is very simple, its impact on the performance is substantial. By addressing the training-inference discrepancy, the model is able to learn more effectively. Section 5.3 provides further experiments on various weight choices that support the choice of our weights. + +# 4. Experimental Setup + +# 4.1. Dataset + +Similar to prior works on online action detection, we evaluate MiniROAD on two publicly-available datasets: THUMOS'14 and TVSeries. In addition, we use a large FineAction dataset for performance evaluation. + +THUMOS'14 [19] comprises over 20 hours of sports video, e.g. baseball pitch, each annotated with 20 actions. Following the prior works [3, 43], we train on the validation set (200 untrimmed videos) and evaluate on the test set (213 untrimmed videos). + +TVSeries [7] consists of 27 episodes of six popular TV shows, spanning 16 hours. It is annotated with 30 real-life everyday actions like opening doors, running, and drinking. It proposes unique challenges as it has a diverse viewpoint, heavy occlusion, and a large portion of background frames. + +FineAction [24] is a large dataset introduced for Temporal Action Detection with more detailed activity descriptions with varying difficulties. It consists of 16,732 untrimmed videos spanning 705 video hours with 103,324 temporal instances of 106 action categories. + +# 4.2. Setting + +Feature Extraction. As the selection of a feature extractor is an important factor that directly affects the performance, we follow the experimental settings of the state-of-the-art methods [43, 3, 40]. For THUMOS and TVSeries, we first sample the videos into 24 FPS and feed non-overlapping snippets to the feature extractor. The snippet + +size is set to 6 and TSN [34] is adopted as the feature extractor. We employ implementation and checkpoints from MMACTION [6] and experiment with feature extractors pretrained on Kinetics-400 [2] and Activitynet1.3 [17]. For FineAction Dataset, we use the officially available features extracted using a Two-Stream architecture [32]. This architecture feeds non-overlapping snippets of 16 RGB or optical flow frames to two separate I3D [2] models that were pretrained with Kinetics. Since the officially available feature is too condensed (16 frames being converted into one feature) and causes overlooking of the fine-grained action instances, we linearly interpolate the temporal resolution of the feature sequence by a factor of four. For all experiments, the visual and motion features are concatenated along the channel dimension before feeding into the model. + +Implementation Details. To substantiate our claim that mitigating the training-inference discrepancy leads to more effective training of RNN models, we adopt a minimalist approach in designing our model. Our model comprises an embedding layer, a GRU, and a classification layer. Despite its simplicity, our model achieves comparable or even better performance to the state-of-the-art methods thanks to maximizing RNN's potential with our proposed methodology, while its lightweight property makes it highly efficient. + +Implementation details can be found in the officially available code. Experiments are conducted using Nvidia RTX3090 Graphics cards. + +# 4.3. Evaluation Metrics + +To evaluate the performance of our methodology, we follow prior works and report per-frame mean Average Precision (mAP) on the THUMOS'14 dataset and per-frame mean calibrated Average Precision (mcAP) on the TVSeries dataset. Per-frame mAP is adopted for the FineAction Dataset as well. For measuring mAP, we collect all the classification scores for each frame and calculate the precision and recall based on the sorted results. We then calculate the Average Precision for each class using the precision and recall values and average the results over all classes to obtain the mAP. The mcAP, introduced by [7] with the TVSeries dataset, was proposed to address the imbalance between positive and negative samples. Calibrated average precision (cAP) is calculated using the formula + +$$ +c A P = \frac {\sum_ {i} c P r e c (i) \cdot I (i)}{\sum_ {i} I (i)}, \tag {3} +$$ + +where $I(i)$ is 1 if the frame $i$ is a true positive and $cPrec$ is calculated by + +$$ +c P r e c = \frac {w \cdot T P}{w \cdot T P + F P}. \tag {4} +$$ + +where $w$ is the ratio between negative and positive samples. + +
MethodBackboneParametersGFLOPsmAP (%)
TRN[39]402.9M1.4662.1
OadTR[36]75.8M2.5465.2
LSTR[40]TSN58.0M7.5369.5
GateHUB[3](Kinetics)45.2M6.9870.7
TeSTra[43]58.9M4.3771.2
MiniROAD (Ours)15.8M0.015871.8
+ +Table 1: Comparison to other recent OAD methods in terms of parameter count, GFLOPs, and mAP on THUMOS'14 dataset using the Kinetics pretrained feature extractor. + +# 5. Results and Analysis + +# 5.1. Comparisons with State of the Art + +THUMOS'14. Table 1 presents a comparison of MiniROAD with recent methods on THUMOS'14, using features extracted by the Kinetics-pretrained TSN backbone. We measured the parameter count and GFLOPs of TeSTra and ours by ourselves, and the other numbers are from [3]. We can see that MiniROAD outperforms state-of-the-art methods on THUMOS'14 by $0.6\%$ in mAP while requiring only $0.4\%$ GFLOPs and $27\%$ parameters. There is a significant gain in efficiency thanks to the RNN architecture. RNN's advantage in efficiency can be also seen by TRN. Despite its large number of parameters, TRN requires the least number of computations compared to the recent works as recent works employ transformer architecture that needs a lot more computation overhead for calculating attention. These large gains in efficiency suggest that RNNs have a significant advantage in online settings, specifically for those that require real-time processing. To validate the generalization of our method, we also evaluate the same dataset using the feature extractor pretrained with Activitynet. The results are shown in Table 2a and our method achieves the best results in this setting as well. + +TVSeries. Table 2b shows the comparison of our method with the other methods using the features extracted by Kinetics and Activitynet pretrained features. Our method is able to achieve comparable or better performance to the state-of-the-art in this dataset as well. + +FineAction. Table 3 compares the performance of our approach and recent methods on the FineAction Dataset. As we are the first to evaluate this dataset for the OAD task, we reproduced all the results in Table 3 using the publicly available code. Our model outperforms the recent methods, achieving a $17\%$ performance gain over the next best-performing method. This dataset is much larger and contains activities of varying difficulties, in contrast to previously tested datasets that had limited action instances of similar categories. Thus, it provides a more realistic setting and can serve as a valuable benchmark for future OAD research. + +
MethodmAP (%)MethodmcAP (%)
AnetKineticsAnetKinetics
RED [14]45.3-RED[14]79.2-
IDN [12]50.060.3FATS[21]81.784.6
FATS [21]51.659.0IDN[12]84.786.1
TRN [39]47.262.1TRN[39]83.786.2
LAP [29]53.3-TFN[13]85.0-
TFN [13]55.7-LAP[29]85.3-
OadTR [36]58.365.2PKD[42]-86.4
LSTR [40]65.369.5OadTR[36]85.487.2
GateHUB [3]69.170.7LSTR[40]88.189.1
TeSTra [43]68.271.2GateHUB[3]88.489.6
Ours69.371.8Ours88.589.6
+ +(a) +(b) +Table 2: Comparison to other OAD methods on (a) THUMOS'14 [19] dataset and (b) TVSeries dataset [7]. Results using the backbone pre-trained using Activitynet [17] and Kinetics [2] are shown. + +
MethodmAP (%)
OadTR[36]31.8
LSTR[40]31.6
TeSTra[43]31.2
Ours37.1
+ +Table 3: Comparison to other OAD methods on FineAction dataset [24]. + +![](images/3d811e11e5913d2d50001872ab829f7996a5a52deeeb9854715dd1190357a0a0.jpg) +Figure 3: Attention heatmap (top) and its specific values (bottom) of the transformer encoders in OadTR [36]. For the heatmap calculation, all the attention values in the encoder (of every layer and head) are collected for the entire test set input which are then averaged out over the heads. The above shows the collected values after normalization. + +# 5.2. Why is RNN adequate for the task? + +The prevailing reasoning behind the lower performance of RNNs is that they struggle with learning long-range dependencies. This is often attributed to training difficulties such as gradient vanishing that can arise when processing prolonged sequences. Therefore, recent works have been using transformers for OAD as they are particularly proficient at capturing long-term dependencies. However, it is worth asking how much temporal information is actually needed for OAD. + +What do Transformers Actually See? Inspired by the recent success of transformer models in OAD, we analyzed the attention weights within the transformer multi-head attention to gain insights into the model's decision-making process. The visualization results are presented in Figure 3. As evident from the heat map and the graph, the transformer model predominantly focuses on the recent and neighboring frames, indicating the recent input's dominant influence on the prediction. Surprisingly, despite the transformer's intended capability of capturing long-term dependencies, the model mainly relies on the recent frames for making the current frame prediction. Our analysis reinforces the argument that RNN's inductive bias, which prioritizes the current input while retaining meaningful temporal information from the past, is well suited for the task. + +Optimal Length of Temporal Information. Figure 4 shows the performance of our model with varying clip lengths using the proposed methodology. As our methodology trains the model with the loss computed at the end of the clip, the graph shows the trade-off between providing more temporal information and ignoring the supervision of the earlier steps. The figure shows that a saturation point is reached at 32 seconds and providing more information than 32 seconds does not improve the performance. To the commonly held belief that the RNN does not benefit from prolonged sequence length, there exists a model's maximum capacity. It is important to note, however, that RNN's capacity is already enough to perform well on the OAD task, validated by the promising performances shown in Section 5.1. A slight drop in performance after 32 seconds is a result of RNN not being able to use temporal information beyond a certain point and much supervision lost during training. + +# 5.3. What is the optimal weight? + +Our work shows that the uniform weights put on computed loss at each time-step hinders the effective training of the RNNs. To make the most use of the finding, we experimented with varying weight choices $\alpha_{t}$ in (1) at each time step. Different choices of weights including uniform, linearly increasing, exponentially increasing, learnable, and step function, are experimented. The results are shown in Table 4a. The results indicate that assigning uniform + +![](images/54190922a5acbd615dde3e21acd069b8799e42f9ff1968863e756a1de2a561b7.jpg) +Effect of Hidden State Duration on THUMOS 14 +Figure 4: Effect of varying the length of the clip $L$ during training. + +weights to the loss computed at each time-step results in the worst performance, which is consistent with the findings discussed in the paper that this conventional approach impedes the effective training of the model. Applying linearly increasing weights performs better than assigning uniform weights because it places less emphasis on early-stage predictions. The next best performing choice is exponentially increasing weights, which heavily emphasizes the loss computed at later stages. The next best performing weight choice is learnable weights. For this experimental setup, learnable embeddings of size $L$ (length of the clip) were trained. When computing the loss, we apply softmax activation to the learnable weights, which are then multiplied by their corresponding loss at their time steps. This approach shows even better performance than exponentially increasing weights. The best-performing choice of weight is step-function which uses only the loss computed at the end. This results in the best performance as the loss associated with predictions using the informative hidden state best resemble the dominant predictions made at the inference stage. + +# 5.4. Effectiveness of the method + +Table 4b shows the result of our model with and without the proposed non-uniform weights. We can observe that there is a $5\%$ mAP increase by using our proposed methodology. In addition, we also experiment with our proposed methodology using the transformer architecture. For the experiment, we adopt the transformer encoder from OadTR and set the encoding layers to 3 and the number of heads to 8 which is the default setting in the publicly available code. We observe that the performance increases from 63.0 to $64.9\%$ mAP with a $1.9\%$ mAP increase using our proposed methodology. + +
Weight TypemAP (%)
Uniform66.4
Linear68.6
Exponential69.8
Learnable70.8
Step-Function71.8
+ +(a) + +
Method
TransformerMiniROAD
Uniform Weight63.066.4
Proposed64.971.8
+ +(b) +Table 4: (a) Result of applying different weights $\alpha_{t}$ in (1). Otherwise stated, Step-Function is the default choice in our paper which only uses the loss computed at the end of the clip. (b) Result of applying the proposed weights on the transformer-based model and on our model. + +
MethodOF. Comp.RGB Feat.OF. Feat.Model FPSOverall FPSmAP (%)
TRN14320.562.1
OadTR14520.565.2
LSTR28.838321918721.269.5
TeSTra16920.971.2
Ours3730023.871.8
+ +Table 5: Runtime Comparison of OAD methods on THU-MOS'14 dataset with flow features extracted using TV-L1 [41] algorithm. OF. Comp., RGB Feat., and OF. Feat. are the speed of extracting optical flows, rgb features, and optical flow features respectively, measured in FPS. + +# 5.5. Runtime + +Efficiency is a critical aspect of the online nature of the OAD task. To assess efficiency, we compare MiniROAD's runtime with recent methods in frames per second (FPS) using videos from the THUMOS'14 dataset on a system with a single RTX3090 GPU. The results in Table 5 demonstrate that our model's lightweight RNN architecture is very efficient, running about 200 times faster than previous methods. However, it is worth noting that the model's speed is not the final speed, as the input of the OAD model requires the extraction of visual and motion features. As illustrated in Table 5, computing optical flow accounts for the majority of the computation time. The end-to-end speed, which encompasses the speed after computing optical flows, extracting visual and motion features, and passing through the model, is reported as Overall FPS in the table. Although extracting optical flow acts as a bottleneck, the efficiency of our model yields 2.9 gains in FPS overall. These gains in overall speed are further improved when a faster optical flow computing algorithm is used. To demonstrate the efficacy of this approach, we also test using the NVIDIA Optical Flow $\mathrm{SDK}^1$ (NVOFA) for faster optical flow computa + +
MethodPre-TrainmAP@τ0Average
0.250.50.7511.251.51.752
RED [14]45.342.139.637.535.834.433.232.137.5
TRN [39]45.142.440.739.137.736.435.334.338.9
TTM [35]45.943.742.441.039.939.437.937.340.9
LAP-Net [29]49.047.445.343.241.339.738.337.042.6
OadTR [36]ANet1.350.249.348.146.845.343.942.441.145.9
LSTR [40]--------50.1
GateHUB [3]--------54.2
TeSTra [43]64.761.858.755.753.251.149.247.855.3
Ours65.463.360.557.454.851.949.747.756.3
TTM [35]46.845.544.643.641.941.140.438.742.8
LSTR [36]60.458.656.053.350.948.947.145.752.6
OadTR [36]K40059.858.556.654.652.650.548.646.853.5
TeSTra [43]66.263.560.557.454.852.650.548.956.8
Ours68.566.363.560.757.955.653.551.459.7
+ +Table 6: Action Anticipation Results on THUMOS'14 dataset with feature extractor pretrained with Activitynet (top) and Kinetics (bottom). + +
MethodOF. Comp.RGB Feat.OF. Feat.Model FPSOverall FPSmAP (%)
TRN†14366.061.6
OADTR†14566.363.3
LSTR†1K38321918773.867.1
TeSTra16970.967.3
Ours3730012268.4
+ +Table 7: Comparison to other OAD methods on THU-MOS'14 dataset with flow features extracted using NVIDIA OPTICAL FLOW. $\dagger$ was reproduced by us. All the values indicate the speed measured in FPS. + +tion, which runs at around 1K FPS. By utilizing the faster flow algorithm, our model runs at 122 FPS which is 1.72 times faster than the state-of-the-art model. Although there is a degradation in the final performance compared to the traditionally used flow algorithm, this highlights the availability of an alternative approach that can deliver faster end-to-end speed while balancing performance and speed trade-offs. The significant increase in end-to-end speed when using the faster optical flow algorithm indicates that additional increases can be gained with RGB-only inputs, leaving open opportunities for future work. + +# 5.6. Action Anticipation + +As our methodology is also applicable to other online tasks, we extend our method to Action Anticipation, which is a task of anticipating upcoming actions using the histories. Instead of predicting the current time frame, the model is trained to predict the next upcoming actions every 0.25 seconds up to 2 seconds. Table 6 shows the results of predictions at each of that time-step. It shows that our method performs favorably to the other methods with $1\%$ mAP gain using activitynet pretrained backbone and $2.9\%$ mAP gain using kinetics pretrained backbone over the previous state + +of-the-art. While our methodology was initially designed for OAD, its applicability extends beyond OAD and can be used for other similar tasks. + +# 6. Conclusion + +We revisit RNN for online action detection and show its potential in dealing with the task. We identify the training-inference discrepancy as a primary cause of the lower performance of RNNs and address the issue by introducing non-uniform weights to the loss computed at each timesteps. We demonstrate the effectiveness of our proposed method using MiniROAD, a minimal RNN-based OAD model. MiniROAD achieves equal or better accuracy than the existing best method on challenging datasets, with a significant increase in efficiency. With the faster NVOFA, MiniROAD runs at an impressive 122 FPS. + +We note that recent OAD methods rely heavily on optical flows, which impede end-to-end speed. While faster optical flow algorithms like NVOFA can mitigate this issue, flow-free OAD remains an open yet challenging problem. By highlighting the suitability of RNNs for processing streaming videos, we hope to pave the way for further advancements and shed light on developing more efficient models. + +# Acknowledgements + +This work was supported by Samsung Electronics Co., Ltd. (Mobile eXperience Business), Yonsei University Artificial Intelligence Graduate School Program under Grant 2020-0-01361, and by the Institute of Information & communications Technology Planning & Evaluation (IITP) grant funded by the Korea government(MSIT) (No.2022-0-00124, Development of Artificial Intelligence Technology for Self-Improving Competency-Aware Learning Capabilities). The work of Joungbin was in part supported by the Hyundai Motor Chung Mong-Koo Foundation. + +# References + +[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lučić, and Cordelia Schmid. Vivit: A video vision transformer. In IEEE International Conference on Computer Vision (ICCV), pages 6836-6846, 2021. 3 +[2] Joao Carreira and Andrew Zisserman. Quo vadis, action recognition? a new model and the kinetics dataset. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 6299-6308, 2017. 5, 6 +[3] Junwen Chen, Gaurav Mittal, Ye Yu, Yu Kong, and Mei Chen. Gatehub: Gated history unit with background suppression for online action detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 3, 4, 5, 6, 8 +[4] Kyunghyun Cho, Bart Van Merrienboer, Caglar Gulcehre, Dzmitry Bahdanau, Fethi Bougares, Holger Schwenk, and Yoshua Bengio. Learning phrase representations using rnn encoder-decoder for statistical machine translation. arXiv preprint arXiv:1406.1078, 2014. 2 +[5] Junyoung Chung, Caglar Gulcehre, KyungHyun Cho, and Yoshua Bengio. Empirical evaluation of gated recurrent neural networks on sequence modeling. arXiv preprint arXiv:1412.3555, 2014. 1, 3 +[6] MMAction2 Contributors. Openmmlab's next generation video understanding toolbox and benchmark. https://github.com/open-mmlab/mmaction2, 2020.5 +[7] Roeland De Geest, Efstratios Gavves, Amir Ghodrati, Zhenyang Li, Cees Snoek, and Tinne Tuytelaars. Online action detection. In European Conference on Computer Vision (ECCV), pages 269-284. Springer, 2016. 1, 2, 4, 5, 6 +[8] Roeland De Geest and Tinne Tuytelaars. Modeling temporal structure with lstm for online action detection. In IEEE Winter Conference on Applications of Computer Vision (WACV), pages 1549-1557. IEEE, 2018. 2 +[9] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. arXiv preprint arXiv:1810.04805, 2018. 1, 3 +[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020. 1, 3 +[11] Jeffrey L Elman. Finding structure in time. Cognitive science, 14(2):179-211, 1990. 1 +[12] Hyunjun Eun, Jinyoung Moon, Jongyoul Park, Chanho Jung, and Changick Kim. Learning to discriminate information for online action detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2020. 2, 6 +[13] Hyunjun Eun, Jinyoung Moon, Jongyoul Park, Chanho Jung, and Changick Kim. Temporal filtering networks for online action detection. Pattern Recognition, 111:107695, 2021. 6 +[14] Jiyang Gao, Zhenheng Yang, and Ram Nevatia. Red: Reinforced encoder-decoder networks for action anticipation. arXiv preprint arXiv:1707.04818, 2017. 2, 6, 8 + +[15] Mingfei Gao, Yingbo Zhou, Ran Xu, Richard Socher, and Caiming Xiong. Woad: Weakly supervised online action detection in untrimmed videos. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1915-1923, 2021. 2 +[16] Albert Gu, Karan Goel, and Christopher Ré. Efficiently modeling long sequences with structured state spaces. arXiv preprint arXiv:2111.00396, 2021. 3 +[17] Fabian Caba Heilbron, Victor Escorcia, Bernard Ghanem, and Juan Carlos Niebles. Activitynet: A large-scale video benchmark for human activity understanding. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 961-970. IEEE, 2015. 5, 6 +[18] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 9(8):1735-1780, 1997. 1, 2, 3 +[19] Haroon Idrees, Amir R Zamir, Yu-Gang Jiang, Alex Gorban, Ivan Laptev, Rahul Sukthankar, and Mubarak Shah. The thumos challenge on action recognition for videos "in the wild". Computer Vision and Image Understanding(CVIU), 155:1-23, 2017. 4, 6 +[20] Jinkyu Kim, Teruhisa Misu, Yi-Ting Chen, Ashish Tawari, and John Canny. Grounding human-to-vehicle advice for self-driving vehicles. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 10591–10599, 2019. 1 +[21] Young Hwi Kim, Seonghyeon Nam, and Seon Joo Kim. Temporally smooth online action detection using cycle-consistent future anticipation. Pattern Recognition, 116:107954, 2021. 2, 6 +[22] Serkan Kiranyaz, Onur Avci, Osama Abdeljaber, Turker Ince, Moncef Gabbouj, and Daniel J Inman. 1d convolutional neural networks and applications: A survey. Mechanical systems and signal processing, 151:107398, 2021. 3 +[23] Zachary C Lipton, John Berkowitz, and Charles Elkan. A critical review of recurrent neural networks for sequence learning. arXiv preprint arXiv:1506.00019, 2015. 1, 2 +[24] Yi Liu, Limin Wang, Yali Wang, Xiao Ma, and Yu Qiao. Fineaction: A fine-grained video dataset for temporal action localization. IEEE Transactions on Image Processing, 2022, 4, 6 +[25] Antonio Orvieto, Samuel L Smith, Albert Gu, Anushan Fernando, Caglar Gulcehre, Razvan Pascanu, and Soham De. Resurrecting recurrent neural networks for long sequences. arXiv preprint arXiv:2303.06349, 2023. 3 +[26] Guansong Pang, Cheng Yan, Chunhua Shen, Anton van den Hengel, and Xiao Bai. Self-trained deep ordinal regression for end-to-end video anomaly detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 12173-12182, 2020. 1 +[27] Hyunjong Park, Jongyoun Noh, and Bumsub Ham. Learning memory-guided normality for anomaly detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 14372-14381, 2020. 1 +[28] Bo Peng, Eric Alcaide, Quentin Anthony, Alon Albalak, Samuel Arcadinho, Huanqi Cao, Xin Cheng, Michael Chung, Matteo Grella, Kranthi Kiran GV, et al. Rwkv: + +Reinventing rnns for the transformer era. arXiv preprint arXiv:2305.13048, 2023. 3 +[29] Sanqing Qu, Guang Chen, Dan Xu, Jinhu Dong, Fan Lu, and Alois Knoll. Lap-net: Adaptive features sampling via learning action progression for online action detection. arXiv preprint arXiv:2011.07915, 2020. 6, 8 +[30] Mike Schuster and Kuldip K Paliwal. Bidirectional recurrent neural networks. IEEE transactions on Signal Processing, 45(11):2673-2681, 1997. 1, 4 +[31] Tianmin Shu, Dan Xie, Brandon Rothrock, Sinisa Todorovic, and Song Chun Zhu. Joint inference of groups, events and human roles in aerial videos. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 4576-4584, 2015. 1 +[32] Karen Simonyan and Andrew Zisserman. Two-stream convolutional networks for action recognition in videos. Conference on Neural Information Processing Systems (NeurIPS), 27, 2014. 5 +[33] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Conference on Neural Information Processing Systems (NeurIPS), 30, 2017. 1, 3 +[34] Limin Wang, Yuanjun Xiong, Zhe Wang, Yu Qiao, Dahua Lin, Xiaou Tang, and Luc Van Gool. Temporal segment networks: Towards good practices for deep action recognition. In European Conference on Computer Vision (ECCV), pages 20-36. Springer, 2016. 5 +[35] Wen Wang, Xiaojiang Peng, Yanzhou Su, Yu Qiao, and Jian Cheng. Tpp: Temporal transformer with progressive prediction for efficient action anticipation. Neurocomputing, 438:270-279, 2021. 8 +[36] Xiang Wang, Shiwei Zhang, Zhiwu Qing, Yuanjie Shao, Zhengrong Zuo, Changxin Gao, and Nong Sang. Oadtr: Online action detection with transformers. IEEE International Conference on Computer Vision (ICCV), 2021. 2, 5, 6, 8 +[37] Paul J Werbos. Backpropagation through time: what it does and how to do it. Proceedings of the IEEE, 78(10):1550-1560, 1990. 2 +[38] Chao-Yuan Wu, Yanghao Li, Karttikeya Mangalam, Haoqi Fan, Bo Xiong, Jitendra Malik, and Christoph Feichtenhofer. Memvit: Memory-augmented multiscale vision transformer for efficient long-term video recognition. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 13587-13597, 2022. 3 +[39] Mingze Xu, Mingfei Gao, Yi-Ting Chen, Larry S. Davis, and David J. Crandall. Temporal recurrent networks for online action detection. In IEEE International Conference on Computer Vision (ICCV), 2019. 2, 5, 6, 8 +[40] Mingze Xu, Yuanjun Xiong, Hao Chen, Xinyu Li, Wei Xia, Zhuowen Tu, and Stefano Soatto. Long short-term transformer for online action detection. In Conference on Neural Information Processing Systems (NeurIPS), 2021. 2, 4, 5, 6, 8 +[41] Christopher Zach, Thomas Pock, and Horst Bischof. A duality based approach for realtime tv-l 1 optical flow. In Pattern Recognition, pages 214-223. Springer, 2007. 7 + +[42] Peisen Zhao, Lingxi Xie, Ya Zhang, Yanfeng Wang, and Qi Tian. Privileged knowledge distillation for online action detection. arXiv preprint arXiv:2011.09158, 2020. 6 +[43] Yue Zhao and Philipp Krahenbuhl. Real-time online video detection with temporal smoothing transformers. In European Conference on Computer Vision (ECCV), 2022. 3, 4, 5, 6, 8 \ No newline at end of file diff --git a/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/images.zip b/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..9ca560294cbb03a1d8692f5c87a33721ddfc94c6 --- /dev/null +++ b/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:20c6d3a2f52a54a44eaba5932cd2e3e1f585da20cef66cbdec6ce36d82bccd70 +size 350611 diff --git a/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/layout.json b/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..9fde582b6f9baa0ee2f09a0b87630814aef06970 --- /dev/null +++ b/2023/MiniROAD_ Minimal RNN Framework for Online Action Detection/layout.json @@ -0,0 +1,7175 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 87, + 103, + 506, + 119 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 87, + 103, + 506, + 119 + ], + "spans": [ + { + "bbox": [ + 87, + 103, + 506, + 119 + ], + "type": "text", + "content": "MiniROAD: Minimal RNN Framework for Online Action Detection" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "spans": [ + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "text", + "content": "Joungbin An" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "text", + "content": " Hyolim Kang" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "text", + "content": " Su Ho Han" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "text", + "content": " Ming-Hsuan Yang" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "inline_equation", + "content": "^{1,2,3}" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "text", + "content": " Seon Joo Kim" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "text", + "content": "Yonsei University " + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "text", + "content": "UC Merced " + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 79, + 142, + 514, + 172 + ], + "type": "text", + "content": "Google Research" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 199, + 192, + 211 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 199, + 192, + 211 + ], + "spans": [ + { + "bbox": [ + 143, + 199, + 192, + 211 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 224, + 290, + 489 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 224, + 290, + 489 + ], + "spans": [ + { + "bbox": [ + 47, + 224, + 290, + 489 + ], + "type": "text", + "content": "Online Action Detection (OAD) is the task of identifying actions in streaming videos without access to future frames. Much effort has been devoted to effectively capturing long-range dependencies, with transformers receiving the spotlight for their ability to capture long-range temporal structures. In contrast, RNNs have received less attention lately, due to their lower performance compared to recent methods that utilize transformers. In this paper, we investigate the underlying reasons for the inferior performance of RNNs compared to transformer-based algorithms. Our findings indicate that the discrepancy between training and inference is the primary hindrance to the effective training of RNNs. To address this, we propose applying non-uniform weights to the loss computed at each time step, which allows the RNN model to learn from the predictions made in an environment that better resembles the inference stage. Extensive experiments on three benchmark datasets, THU-MOS, TVSeries, and FineAction demonstrate that a minimal RNN-based model trained with the proposed methodology performs equally or better than the existing best methods with a significant increase in efficiency. The code is available at https://github.com/jbistanbul/MiniROAD." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 512, + 128, + 525 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 512, + 128, + 525 + ], + "spans": [ + { + "bbox": [ + 47, + 512, + 128, + 525 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 533, + 287, + 665 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 533, + 287, + 665 + ], + "spans": [ + { + "bbox": [ + 46, + 533, + 287, + 665 + ], + "type": "text", + "content": "Online Action Detection (OAD) is a challenging task that involves identifying actions taking place in a streaming video without access to future frames. Since its introduction [7], OAD has gained great attention in research circles, as it has numerous real-world applications, such as autonomous driving [20], smart surveillance systems [26, 27], and anomaly detection [31]. These applications require the ability to process streaming videos in real-time, making OAD an essential component of many advanced systems. As a result, there has been a growing interest in developing more accurate and efficient methods for performing OAD." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 665, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 288, + 714 + ], + "type": "text", + "content": "To address the challenges of OAD, recent efforts have focused on developing novel models for analyzing streaming videos in real-time. The conventional process of OAD consists of two stages. In the first stage, frames are con" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 326, + 206, + 513, + 376 + ], + "blocks": [ + { + "bbox": [ + 326, + 206, + 513, + 376 + ], + "lines": [ + { + "bbox": [ + 326, + 206, + 513, + 376 + ], + "spans": [ + { + "bbox": [ + 326, + 206, + 513, + 376 + ], + "type": "image", + "image_path": "4e46ec5a3f87f4a85b8ba9bc6e9b9c937b50a833faf5ba68ef3179f3e503bed4.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 305, + 387, + 545, + 410 + ], + "lines": [ + { + "bbox": [ + 305, + 387, + 545, + 410 + ], + "spans": [ + { + "bbox": [ + 305, + 387, + 545, + 410 + ], + "type": "text", + "content": "Figure 1: Performance of recent OAD methods with respect to GFLOPs and the model's size." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 422, + 547, + 495 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 422, + 547, + 495 + ], + "spans": [ + { + "bbox": [ + 304, + 422, + 547, + 495 + ], + "type": "text", + "content": "verted into a sequence of features by a feature extractor. In the second stage, the extracted features are processed to capture the temporal information required for performing OAD. Much attention on OAD research has been paid to this second stage where the two mainstream models are RNNs [11, 30, 18, 5] and Transformers [9, 10, 33]." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 496, + 547, + 602 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 496, + 547, + 602 + ], + "spans": [ + { + "bbox": [ + 304, + 496, + 547, + 602 + ], + "type": "text", + "content": "Each model has its strengths and weaknesses. RNNs can capture temporal transitions effectively by modeling sequences recurrently but are known for their training difficulties [23, 30]. Transformers can capture long-term dependencies through self-attention, however, attention computation is computationally expensive. Although recent research has shifted towards using Transformer models, our paper revisits RNN, which has been overlooked in recent studies." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 547, + 715 + ], + "type": "text", + "content": "In this work, we show that RNN's intrinsic inductive bias—prioritizing the current input while preserving meaningful temporal information from the histories—makes them well-suited for OAD. Unlike in natural language processing, where a distant word can significantly affect the next sequence prediction, we observe that in OAD, the current and its neighboring frames have a dominant influence on the current prediction. In addition, RNN is efficient, as it requires a small computational overhead compared to" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10341" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 287, + 96 + ], + "type": "text", + "content": "the transformer models, making them well-suited for online tasks that require running in real-time." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 98, + 286, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 98, + 286, + 193 + ], + "spans": [ + { + "bbox": [ + 46, + 98, + 286, + 193 + ], + "type": "text", + "content": "Despite its architecture being well-suited for the OAD task, RNN has been recently overlooked due to the promising results shown by transformer-based models. The prevailing reasoning behind the lower performance of RNN based method was the difficulty of learning long-range dependencies [37, 23]. In this paper, we find that it is the training-inference discrepancy that hinders the effective training of RNNs." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 195, + 286, + 422 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 195, + 286, + 422 + ], + "spans": [ + { + "bbox": [ + 46, + 195, + 286, + 422 + ], + "type": "text", + "content": "During inference, the video is processed frame-by-frame in a streaming fashion. During training, however, the video is divided into multiple clips, which are then fed to the model, as illustrated in Figure 2. This creates a significant discrepancy between the two phases since videos are usually much longer than the training clips. Consequently, the clips provide limited temporal information, leading to a restricted view of the video during training. This limitation is not as problematic for recent OAD models using transformers as it is for models using RNNs. This is because recent transformer models utilize the temporal information between clips using explicit long-term memory even during training. At the same time, RNNs do not since they receive a non-informative hidden state initialized as zero at the beginning of the clip. As a result, RNNs make most predictions during training with the hidden state that lacks temporal information, whereas it makes most predictions during inference with the hidden state accumulated with sufficient temporal information." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 424, + 286, + 651 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 424, + 286, + 651 + ], + "spans": [ + { + "bbox": [ + 46, + 424, + 286, + 651 + ], + "type": "text", + "content": "We demonstrate that addressing the training and inference discrepancy in RNNs alone can significantly improve their performance without requiring any changes to their architecture. Specifically, we find that introducing nonuniform weights to losses at different time steps can alleviate this discrepancy, which is a primary factor contributing to RNN's suboptimal performance. This approach differs from the conventional assumption of averaging the loss over the joint prediction, as we demonstrate that non-uniform weights to the loss are essential for effectively training the model. We demonstrate the effectiveness of our methodology using Minimal Recurrent neural network for Online Action Detection (MiniROAD), which is a lightweight GRU based model. Figure 1 shows the comparison of our model with other recent models in terms of the model's performance, GFLOPs, and size. It shows that our method with only " + }, + { + "bbox": [ + 46, + 424, + 286, + 651 + ], + "type": "inline_equation", + "content": "\\sim 0.4\\%" + }, + { + "bbox": [ + 46, + 424, + 286, + 651 + ], + "type": "text", + "content": " computational power needed for the previous state-of-the-art, is able to achieve better performance." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 653, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 286, + 712 + ], + "type": "text", + "content": "Our model is evaluated on conventional OAD benchmark datasets, including THUMOS'14 and TVSeries, as well as on the recently introduced FineAction dataset. As conventional datasets used for benchmarking OAD tasks are relatively small, the much larger FineAction dataset offers" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 156 + ], + "type": "text", + "content": "a more challenging testbed that better depicts real-life scenarios. Larger datasets like FineAction open up more possibilities for future work on OAD and hence our results can serve as a strong baseline. Our experiments show that our proposed methodologies achieve on-par or better results on the benchmarked dataset with significant improvements in efficiency." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 317, + 157, + 482, + 167 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 157, + 482, + 167 + ], + "spans": [ + { + "bbox": [ + 317, + 157, + 482, + 167 + ], + "type": "text", + "content": "The main contributions of this work are:" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 317, + 170, + 545, + 373 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 317, + 170, + 545, + 240 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 170, + 545, + 240 + ], + "spans": [ + { + "bbox": [ + 317, + 170, + 545, + 240 + ], + "type": "text", + "content": "- We revisit the potential of RNNs and identify the training-inference discrepancy as a primary cause of their lower performance. To address this issue, we propose a simple yet effective method that makes RNN both effective and efficient in capturing the essential temporal information for online action detection." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 242, + 545, + 336 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 242, + 545, + 336 + ], + "spans": [ + { + "bbox": [ + 317, + 242, + 545, + 336 + ], + "type": "text", + "content": "- Extensive experimental results show that the proposed method performs favorably against the state-of-the-art with high efficiency; our model with only " + }, + { + "bbox": [ + 317, + 242, + 545, + 336 + ], + "type": "inline_equation", + "content": "\\sim 0.4\\%" + }, + { + "bbox": [ + 317, + 242, + 545, + 336 + ], + "type": "text", + "content": " computational overhead compared to the existing methods, achieves on par or better performance on a challenging benchmark dataset, with " + }, + { + "bbox": [ + 317, + 242, + 545, + 336 + ], + "type": "inline_equation", + "content": "\\sim 17\\%" + }, + { + "bbox": [ + 317, + 242, + 545, + 336 + ], + "type": "text", + "content": " performance improvement over the state-of-the-art in a large-scale dataset." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 317, + 337, + 545, + 373 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 337, + 545, + 373 + ], + "spans": [ + { + "bbox": [ + 317, + 337, + 545, + 373 + ], + "type": "text", + "content": "- We expand our methodology and carry out performance evaluation on Action Anticipation and show the applicability of our method on other online tasks." + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 386, + 392, + 398 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 386, + 392, + 398 + ], + "spans": [ + { + "bbox": [ + 306, + 386, + 392, + 398 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 406, + 441, + 418 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 406, + 441, + 418 + ], + "spans": [ + { + "bbox": [ + 306, + 406, + 441, + 418 + ], + "type": "text", + "content": "2.1. Online Action Detection" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 426, + 545, + 652 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 426, + 545, + 652 + ], + "spans": [ + { + "bbox": [ + 304, + 426, + 545, + 652 + ], + "type": "text", + "content": "The Online Action Detection task [7] involves detecting actions in the current frame online, using information from the past up to the present. Earlier approaches to Online Action Detection relied on recurrent models. Geest et al. propose a two-stream feedback network [8], utilizing LSTM [18] where one stream focuses on feature representation and the other on temporal patterns. RED [14] takes advantage of reinforcement learning to make action predictions as early as possible. Recent works using RNNs focus on designing more effective RNN cells. TRN [39] models a greater temporal context by having the LSTM cell [18] anticipate the future. IDN [12] uses the GRU cell [4] to explicitly differentiate relevant information for ongoing actions. In [21], FATSnet employs GRU to perform future anticipation and temporal smoothing for more effective current prediction. On the other hand, WOAD [15] introduces a method for weakly supervised online action detection. Existing RNN-based models mainly concentrate on developing more powerful RNN architectures to handle the task." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": "Transformers have also been used for the OAD task. OadTR [36] introduces a transformer encoder-decoder architecture for capturing long-term relations through self-attention. In [40], LSTR achieves significant performance improvements by employing a two-stage memory compres" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "10342" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 82, + 68, + 516, + 225 + ], + "blocks": [ + { + "bbox": [ + 82, + 68, + 516, + 225 + ], + "lines": [ + { + "bbox": [ + 82, + 68, + 516, + 225 + ], + "spans": [ + { + "bbox": [ + 82, + 68, + 516, + 225 + ], + "type": "image", + "image_path": "4d0ae3b1f4473b1a80ada65e4806ee0f0cf3396eb661b01f31bac37af0b86b4f.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 234, + 547, + 296 + ], + "lines": [ + { + "bbox": [ + 46, + 234, + 547, + 296 + ], + "spans": [ + { + "bbox": [ + 46, + 234, + 547, + 296 + ], + "type": "text", + "content": "Figure 2: Illustration of Training and Inference Discrepancy. During the inference stage (top), frames are fed to the model sequentially in a streaming fashion. The hidden state evolves across the entire video, progressively incorporating accumulated temporal context (depicted as darkening over time). In the training stage (bottom), the video is divided into shorter clips of length " + }, + { + "bbox": [ + 46, + 234, + 547, + 296 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 46, + 234, + 547, + 296 + ], + "type": "text", + "content": ", serving as model inputs. Here, the model solely relies on temporal information within each clip, lacking inter-clip associations. This yields dominant predictions constrained by clip-specific information." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 307, + 289, + 426 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 307, + 289, + 426 + ], + "spans": [ + { + "bbox": [ + 46, + 307, + 289, + 426 + ], + "type": "text", + "content": "sion design with transformers, allowing for capturing long-term temporal and short-term context through self-attention. This two-stage memory design has been further advanced in subsequent works. GateHUB [3] improves the two-stage architecture with a Gated History Unit to address the limitations of prior cross-attention methods. This avoids incorrect current frame predictions by appropriately weighting informative and uninformative frames. Recently, TeSTra [43] extends the LSTR architecture by introducing two temporal smoothing kernels to reduce inference computation cost." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 429, + 288, + 513 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 429, + 288, + 513 + ], + "spans": [ + { + "bbox": [ + 46, + 429, + 288, + 513 + ], + "type": "text", + "content": "Although these transformer models have achieved state-of-the-art results, the attention computation involved in encoding long-term and short-term memory is computationally expensive. In this work, we show that RNNs, without modifying the internals of the architecture, can be just as effective in processing streaming videos with the proposed methodology alone." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 525, + 162, + 539 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 525, + 162, + 539 + ], + "spans": [ + { + "bbox": [ + 47, + 525, + 162, + 539 + ], + "type": "text", + "content": "2.2. Sequence Modeling" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 546, + 289, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 546, + 289, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 546, + 289, + 714 + ], + "type": "text", + "content": "As many real-world applications involve processing time-series data, sequential modeling has been a topic of ongoing research. Recurrent Neural Networks (RNNs) are one of the most commonly used models for sequence modeling, with popular variants including [18] and [5]. These variants introduce mechanisms within the RNN cell to improve its memory capacity while attending to important parts of the sequential data. 1D CNNs [22] incorporate convolution operations to capture the temporal structure of time-series data. Recent advances have been made using transformers [33] that incorporate attention mechanisms for capturing short and long-term dependencies. Ever since its success in the language domain, its use has been widespread in various fields [10, 9, 1, 38]." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 307, + 547, + 487 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 307, + 547, + 487 + ], + "spans": [ + { + "bbox": [ + 304, + 307, + 547, + 487 + ], + "type": "text", + "content": "There have been ongoing efforts on exploring non-transformer architectures. Gu et al. [16] introduces the State Space Model (SSM) in tackling sequence data, proving its efficacy in effectively handling long sequences. A recent work [25] demonstrates that RNNs can match the performance and training speed of SSMs by applying techniques such as linearizing and diagonalizing the recurrence, along with better parameterizations and initializations. Recently, there has been a notable surge in interest surrounding a novel variant of RNN called RWKV [28]. This architecture is the first non-transformer model to be successfully scaled to tens of billions of parameters, bringing together the efficient parallelizable training of transformers with the inference efficiency of RNNs. Our research aligns with these works in resurrecting RNNs in the transformer era." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 518, + 389, + 533 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 518, + 389, + 533 + ], + "spans": [ + { + "bbox": [ + 306, + 518, + 389, + 533 + ], + "type": "text", + "content": "3. Methodology" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": "Provided a live streaming video, our objective is to recognize actions in the current frame based on past observations up to the current time. Since " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "v_{1}^{t}" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": ", a streaming video from the start until the current time " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": " only provides observations " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\{v_{1},\\dots,v_{t}\\}" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": " for the past " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": " frames, it is not possible to access any information beyond " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "v_{t}" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": ". In this setting, the task is to use " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "v_{1}^{t}" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": " to predict " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\hat{y}_t \\in \\{0,1,\\dots,K\\}" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": " where " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": " is the number of action classes and index 0 is the background class. During training, the video is divided into clips, each of length " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": ", and hence clips of " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "v_{t - L}^{t}" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": " are given as input. Following the convention, we suppose that a pre-trained feature extractor is available which can convert each frame " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "v_{t}" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": " into a feature vector " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "f_{t} \\in \\mathbb{R}^{C}" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": ". Our method employs the feature vector " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "f_{t}" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": " as the input at current time " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": " to predict " + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\hat{y}_t" + }, + { + "bbox": [ + 304, + 546, + 547, + 715 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 8 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "10343" + } + ] + } + ], + "index": 9 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 115, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 115, + 83 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 115, + 83 + ], + "type": "text", + "content": "3.1. Overview" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 90, + 289, + 282 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 90, + 289, + 282 + ], + "spans": [ + { + "bbox": [ + 46, + 90, + 289, + 282 + ], + "type": "text", + "content": "Our method is developed based on the observation that a discrepancy exists between the training and the inference stages, which hinders the effective training of sequence-to-sequence models. Figure 2 illustrates this training-inference discrepancy in more detail. While during inference the model receives temporal information from the beginning of the video to the current time step " + }, + { + "bbox": [ + 46, + 90, + 289, + 282 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 90, + 289, + 282 + ], + "type": "text", + "content": ", in training, the model is provided with temporal information from " + }, + { + "bbox": [ + 46, + 90, + 289, + 282 + ], + "type": "inline_equation", + "content": "t - L" + }, + { + "bbox": [ + 46, + 90, + 289, + 282 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 90, + 289, + 282 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 90, + 289, + 282 + ], + "type": "text", + "content": ". Consequently, for each video, clips make predictions using the hidden state that lacks temporal information, which critically affects the losses associated with the early predictions. However, we observe that the conventional approach unknowingly assigns the same uniform weight to all losses for each time step. Our proposed method applies different weights to losses at different time steps, resulting in better training convergence and improved model performance." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 288, + 272, + 301 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 288, + 272, + 301 + ], + "spans": [ + { + "bbox": [ + 47, + 288, + 272, + 301 + ], + "type": "text", + "content": "3.2. Alleviating Training-Inference Discrepancy" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 306, + 287, + 331 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 306, + 287, + 331 + ], + "spans": [ + { + "bbox": [ + 47, + 306, + 287, + 331 + ], + "type": "text", + "content": "The conventional loss calculation for OAD follows the following cross-entropy calculation:" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 111, + 337, + 287, + 370 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 337, + 287, + 370 + ], + "spans": [ + { + "bbox": [ + 111, + 337, + 287, + 370 + ], + "type": "interline_equation", + "content": "- \\sum_ {t = 1} ^ {L} \\sum_ {k = 0} ^ {K} \\alpha_ {t} \\hat {y} _ {t, k} \\log \\left(\\hat {s} _ {t, k}\\right), \\tag {1}", + "image_path": "f16f33070ac8842425096e7c6b49af8a092df4e537aedc39c5b80762afe23f64.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "spans": [ + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "inline_equation", + "content": "\\hat{y}_{t,k}" + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "inline_equation", + "content": "\\hat{s}_{t,k}" + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "text", + "content": " represent the ground truth and predicted logit at time " + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "inline_equation", + "content": "\\alpha_{t} \\in \\{\\alpha_{1}, \\alpha_{2}, \\dots, \\alpha_{L}\\}" + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "text", + "content": " is the weight applied to the loss at each time step, and " + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "inline_equation", + "content": "K" + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "text", + "content": " are the number of classes and the length of the clip, respectively. We pay attention to the fact that the conventional approach has been unknowingly setting the weight " + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "inline_equation", + "content": "\\alpha_{t}" + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "text", + "content": " uniformly for every time-step in the clip, resulting in " + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "inline_equation", + "content": "\\alpha_{t} = 1 / L" + }, + { + "bbox": [ + 46, + 376, + 287, + 506 + ], + "type": "text", + "content": ". However, we show that setting weights uniformly like this, equivalent to using the joint prediction of all time steps, hinders the RNN from being effectively trained as it does not resemble the inference stage." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 507, + 288, + 686 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 507, + 288, + 686 + ], + "spans": [ + { + "bbox": [ + 46, + 507, + 288, + 686 + ], + "type": "text", + "content": "Our goal is to alleviate the problem caused by the discrepancy between the training and inference stages. To do so, we first pay careful attention to what is happening in the inference stage where RNN's temporal capacity plays an important role. During the inference stage, temporal information can accumulate as much as the length of the whole video. Although sequence-to-sequence modeling, in theory, can have an unlimited continuous context length, it is known to have a limited temporal capacity [30], the maximum amount of information in which the RNN can retain. For the task of handling streaming videos, as the videos are long, most predictions are made utilizing the information within its limited capacity. This means that RNN uses the temporal information within RNN's temporal capacity for most predictions during inference." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 689, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 689, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 689, + 287, + 714 + ], + "type": "text", + "content": "Selected Weights. From the above reasons, we choose to apply the weights that enable the RNN to utilize its maxi-" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 72, + 503, + 84 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 503, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 503, + 84 + ], + "type": "text", + "content": "mum temporal capacity. The weight " + }, + { + "bbox": [ + 306, + 72, + 503, + 84 + ], + "type": "inline_equation", + "content": "\\alpha_{t}" + }, + { + "bbox": [ + 306, + 72, + 503, + 84 + ], + "type": "text", + "content": " is set as:" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 377, + 90, + 545, + 122 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 377, + 90, + 545, + 122 + ], + "spans": [ + { + "bbox": [ + 377, + 90, + 545, + 122 + ], + "type": "interline_equation", + "content": "\\alpha_ {t} = \\left\\{ \\begin{array}{l l} 1 & \\text {i f} t = L \\\\ 0 & \\text {O t h e r w i s e} \\end{array} , \\right. \\tag {2}", + "image_path": "fe3f663af6f4ab6d707f4e979f78f3ec0ad22b8d15f1d645aeb24f8c7cde44be.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 126, + 545, + 281 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 126, + 545, + 281 + ], + "spans": [ + { + "bbox": [ + 304, + 126, + 545, + 281 + ], + "type": "text", + "content": "which is a step function that equals putting masks on all the loss except for the loss at the very last time step in the clip. Applying weights like this during training allows us to 1) disregard the dominant predictions made by using an uninformative hidden state and 2) train the RNN using predictions made by the RNN's sufficient temporal capacity, both of which better reflect the inference stage. As long as the length of the clip " + }, + { + "bbox": [ + 304, + 126, + 545, + 281 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 304, + 126, + 545, + 281 + ], + "type": "text", + "content": " is reasonable enough to exploit RNN's full potential, the prediction made at the end of the clip is more representative of what is actually happening in the inference stage. The choice of " + }, + { + "bbox": [ + 304, + 126, + 545, + 281 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 304, + 126, + 545, + 281 + ], + "type": "text", + "content": ", the length of the clip which directly affects the receptive field of RNN during training, is further experimented with in Section 5.2." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 282, + 545, + 342 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 282, + 545, + 342 + ], + "spans": [ + { + "bbox": [ + 304, + 282, + 545, + 342 + ], + "type": "text", + "content": "While the concept is very simple, its impact on the performance is substantial. By addressing the training-inference discrepancy, the model is able to learn more effectively. Section 5.3 provides further experiments on various weight choices that support the choice of our weights." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 351, + 424, + 365 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 351, + 424, + 365 + ], + "spans": [ + { + "bbox": [ + 305, + 351, + 424, + 365 + ], + "type": "text", + "content": "4. Experimental Setup" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 371, + 364, + 383 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 371, + 364, + 383 + ], + "spans": [ + { + "bbox": [ + 306, + 371, + 364, + 383 + ], + "type": "text", + "content": "4.1. Dataset" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 389, + 545, + 437 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 389, + 545, + 437 + ], + "spans": [ + { + "bbox": [ + 304, + 389, + 545, + 437 + ], + "type": "text", + "content": "Similar to prior works on online action detection, we evaluate MiniROAD on two publicly-available datasets: THUMOS'14 and TVSeries. In addition, we use a large FineAction dataset for performance evaluation." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 437, + 545, + 496 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 437, + 545, + 496 + ], + "spans": [ + { + "bbox": [ + 304, + 437, + 545, + 496 + ], + "type": "text", + "content": "THUMOS'14 [19] comprises over 20 hours of sports video, e.g. baseball pitch, each annotated with 20 actions. Following the prior works [3, 43], we train on the validation set (200 untrimmed videos) and evaluate on the test set (213 untrimmed videos)." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 497, + 545, + 556 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 497, + 545, + 556 + ], + "spans": [ + { + "bbox": [ + 304, + 497, + 545, + 556 + ], + "type": "text", + "content": "TVSeries [7] consists of 27 episodes of six popular TV shows, spanning 16 hours. It is annotated with 30 real-life everyday actions like opening doors, running, and drinking. It proposes unique challenges as it has a diverse viewpoint, heavy occlusion, and a large portion of background frames." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 557, + 545, + 617 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 557, + 545, + 617 + ], + "spans": [ + { + "bbox": [ + 304, + 557, + 545, + 617 + ], + "type": "text", + "content": "FineAction [24] is a large dataset introduced for Temporal Action Detection with more detailed activity descriptions with varying difficulties. It consists of 16,732 untrimmed videos spanning 705 video hours with 103,324 temporal instances of 106 action categories." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 623, + 362, + 635 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 623, + 362, + 635 + ], + "spans": [ + { + "bbox": [ + 306, + 623, + 362, + 635 + ], + "type": "text", + "content": "4.2. Setting" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 641, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 641, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 641, + 545, + 714 + ], + "type": "text", + "content": "Feature Extraction. As the selection of a feature extractor is an important factor that directly affects the performance, we follow the experimental settings of the state-of-the-art methods [43, 3, 40]. For THUMOS and TVSeries, we first sample the videos into 24 FPS and feed non-overlapping snippets to the feature extractor. The snippet" + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10344" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 251 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 251 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 251 + ], + "type": "text", + "content": "size is set to 6 and TSN [34] is adopted as the feature extractor. We employ implementation and checkpoints from MMACTION [6] and experiment with feature extractors pretrained on Kinetics-400 [2] and Activitynet1.3 [17]. For FineAction Dataset, we use the officially available features extracted using a Two-Stream architecture [32]. This architecture feeds non-overlapping snippets of 16 RGB or optical flow frames to two separate I3D [2] models that were pretrained with Kinetics. Since the officially available feature is too condensed (16 frames being converted into one feature) and causes overlooking of the fine-grained action instances, we linearly interpolate the temporal resolution of the feature sequence by a factor of four. For all experiments, the visual and motion features are concatenated along the channel dimension before feeding into the model." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 254, + 287, + 361 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 254, + 287, + 361 + ], + "spans": [ + { + "bbox": [ + 46, + 254, + 287, + 361 + ], + "type": "text", + "content": "Implementation Details. To substantiate our claim that mitigating the training-inference discrepancy leads to more effective training of RNN models, we adopt a minimalist approach in designing our model. Our model comprises an embedding layer, a GRU, and a classification layer. Despite its simplicity, our model achieves comparable or even better performance to the state-of-the-art methods thanks to maximizing RNN's potential with our proposed methodology, while its lightweight property makes it highly efficient." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 362, + 287, + 399 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 362, + 287, + 399 + ], + "spans": [ + { + "bbox": [ + 47, + 362, + 287, + 399 + ], + "type": "text", + "content": "Implementation details can be found in the officially available code. Experiments are conducted using Nvidia RTX3090 Graphics cards." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 407, + 160, + 419 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 407, + 160, + 419 + ], + "spans": [ + { + "bbox": [ + 47, + 407, + 160, + 419 + ], + "type": "text", + "content": "4.3. Evaluation Metrics" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 426, + 287, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 426, + 287, + 594 + ], + "spans": [ + { + "bbox": [ + 46, + 426, + 287, + 594 + ], + "type": "text", + "content": "To evaluate the performance of our methodology, we follow prior works and report per-frame mean Average Precision (mAP) on the THUMOS'14 dataset and per-frame mean calibrated Average Precision (mcAP) on the TVSeries dataset. Per-frame mAP is adopted for the FineAction Dataset as well. For measuring mAP, we collect all the classification scores for each frame and calculate the precision and recall based on the sorted results. We then calculate the Average Precision for each class using the precision and recall values and average the results over all classes to obtain the mAP. The mcAP, introduced by [7] with the TVSeries dataset, was proposed to address the imbalance between positive and negative samples. Calibrated average precision (cAP) is calculated using the formula" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 107, + 602, + 287, + 631 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 107, + 602, + 287, + 631 + ], + "spans": [ + { + "bbox": [ + 107, + 602, + 287, + 631 + ], + "type": "interline_equation", + "content": "c A P = \\frac {\\sum_ {i} c P r e c (i) \\cdot I (i)}{\\sum_ {i} I (i)}, \\tag {3}", + "image_path": "6b06093c99abe15cddd22ebe41e116e770af364f248afb483065216ed00e3ced.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 639, + 287, + 663 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 639, + 287, + 663 + ], + "spans": [ + { + "bbox": [ + 47, + 639, + 287, + 663 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 639, + 287, + 663 + ], + "type": "inline_equation", + "content": "I(i)" + }, + { + "bbox": [ + 47, + 639, + 287, + 663 + ], + "type": "text", + "content": " is 1 if the frame " + }, + { + "bbox": [ + 47, + 639, + 287, + 663 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 47, + 639, + 287, + 663 + ], + "type": "text", + "content": " is a true positive and " + }, + { + "bbox": [ + 47, + 639, + 287, + 663 + ], + "type": "inline_equation", + "content": "cPrec" + }, + { + "bbox": [ + 47, + 639, + 287, + 663 + ], + "type": "text", + "content": " is calculated by" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 114, + 672, + 287, + 697 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 114, + 672, + 287, + 697 + ], + "spans": [ + { + "bbox": [ + 114, + 672, + 287, + 697 + ], + "type": "interline_equation", + "content": "c P r e c = \\frac {w \\cdot T P}{w \\cdot T P + F P}. \\tag {4}", + "image_path": "b183efb2d24165fb7eb135a68e24cdf426acdcb3e6e9ec0de9dc419e10fb3b1b.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 701, + 286, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 701, + 286, + 714 + ], + "spans": [ + { + "bbox": [ + 47, + 701, + 286, + 714 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 701, + 286, + 714 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 47, + 701, + 286, + 714 + ], + "type": "text", + "content": " is the ratio between negative and positive samples." + } + ] + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 307, + 70, + 547, + 141 + ], + "blocks": [ + { + "bbox": [ + 307, + 70, + 547, + 141 + ], + "lines": [ + { + "bbox": [ + 307, + 70, + 547, + 141 + ], + "spans": [ + { + "bbox": [ + 307, + 70, + 547, + 141 + ], + "type": "table", + "html": "
MethodBackboneParametersGFLOPsmAP (%)
TRN[39]402.9M1.4662.1
OadTR[36]75.8M2.5465.2
LSTR[40]TSN58.0M7.5369.5
GateHUB[3](Kinetics)45.2M6.9870.7
TeSTra[43]58.9M4.3771.2
MiniROAD (Ours)15.8M0.015871.8
", + "image_path": "e939f9a725d8fbecdd9d11517bb197c582db758f0063f3ed7fe81e646e16a18c.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_body" + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 153, + 546, + 190 + ], + "lines": [ + { + "bbox": [ + 305, + 153, + 546, + 190 + ], + "spans": [ + { + "bbox": [ + 305, + 153, + 546, + 190 + ], + "type": "text", + "content": "Table 1: Comparison to other recent OAD methods in terms of parameter count, GFLOPs, and mAP on THUMOS'14 dataset using the Kinetics pretrained feature extractor." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 204, + 427, + 217 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 204, + 427, + 217 + ], + "spans": [ + { + "bbox": [ + 306, + 204, + 427, + 217 + ], + "type": "text", + "content": "5. Results and Analysis" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 228, + 489, + 240 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 228, + 489, + 240 + ], + "spans": [ + { + "bbox": [ + 306, + 228, + 489, + 240 + ], + "type": "text", + "content": "5.1. Comparisons with State of the Art" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 250, + 546, + 501 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 250, + 546, + 501 + ], + "spans": [ + { + "bbox": [ + 304, + 250, + 546, + 501 + ], + "type": "text", + "content": "THUMOS'14. Table 1 presents a comparison of MiniROAD with recent methods on THUMOS'14, using features extracted by the Kinetics-pretrained TSN backbone. We measured the parameter count and GFLOPs of TeSTra and ours by ourselves, and the other numbers are from [3]. We can see that MiniROAD outperforms state-of-the-art methods on THUMOS'14 by " + }, + { + "bbox": [ + 304, + 250, + 546, + 501 + ], + "type": "inline_equation", + "content": "0.6\\%" + }, + { + "bbox": [ + 304, + 250, + 546, + 501 + ], + "type": "text", + "content": " in mAP while requiring only " + }, + { + "bbox": [ + 304, + 250, + 546, + 501 + ], + "type": "inline_equation", + "content": "0.4\\%" + }, + { + "bbox": [ + 304, + 250, + 546, + 501 + ], + "type": "text", + "content": " GFLOPs and " + }, + { + "bbox": [ + 304, + 250, + 546, + 501 + ], + "type": "inline_equation", + "content": "27\\%" + }, + { + "bbox": [ + 304, + 250, + 546, + 501 + ], + "type": "text", + "content": " parameters. There is a significant gain in efficiency thanks to the RNN architecture. RNN's advantage in efficiency can be also seen by TRN. Despite its large number of parameters, TRN requires the least number of computations compared to the recent works as recent works employ transformer architecture that needs a lot more computation overhead for calculating attention. These large gains in efficiency suggest that RNNs have a significant advantage in online settings, specifically for those that require real-time processing. To validate the generalization of our method, we also evaluate the same dataset using the feature extractor pretrained with Activitynet. The results are shown in Table 2a and our method achieves the best results in this setting as well." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 506, + 545, + 565 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 506, + 545, + 565 + ], + "spans": [ + { + "bbox": [ + 305, + 506, + 545, + 565 + ], + "type": "text", + "content": "TVSeries. Table 2b shows the comparison of our method with the other methods using the features extracted by Kinetics and Activitynet pretrained features. Our method is able to achieve comparable or better performance to the state-of-the-art in this dataset as well." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 570, + 547, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 547, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 547, + 712 + ], + "type": "text", + "content": "FineAction. Table 3 compares the performance of our approach and recent methods on the FineAction Dataset. As we are the first to evaluate this dataset for the OAD task, we reproduced all the results in Table 3 using the publicly available code. Our model outperforms the recent methods, achieving a " + }, + { + "bbox": [ + 304, + 570, + 547, + 712 + ], + "type": "inline_equation", + "content": "17\\%" + }, + { + "bbox": [ + 304, + 570, + 547, + 712 + ], + "type": "text", + "content": " performance gain over the next best-performing method. This dataset is much larger and contains activities of varying difficulties, in contrast to previously tested datasets that had limited action instances of similar categories. Thus, it provides a more realistic setting and can serve as a valuable benchmark for future OAD research." + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10345" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 48, + 70, + 282, + 207 + ], + "blocks": [ + { + "bbox": [ + 48, + 70, + 282, + 207 + ], + "lines": [ + { + "bbox": [ + 48, + 70, + 282, + 207 + ], + "spans": [ + { + "bbox": [ + 48, + 70, + 282, + 207 + ], + "type": "table", + "html": "
MethodmAP (%)MethodmcAP (%)
AnetKineticsAnetKinetics
RED [14]45.3-RED[14]79.2-
IDN [12]50.060.3FATS[21]81.784.6
FATS [21]51.659.0IDN[12]84.786.1
TRN [39]47.262.1TRN[39]83.786.2
LAP [29]53.3-TFN[13]85.0-
TFN [13]55.7-LAP[29]85.3-
OadTR [36]58.365.2PKD[42]-86.4
LSTR [40]65.369.5OadTR[36]85.487.2
GateHUB [3]69.170.7LSTR[40]88.189.1
TeSTra [43]68.271.2GateHUB[3]88.489.6
Ours69.371.8Ours88.589.6
", + "image_path": "52118ca442809baf475eefe59ce2ca8cfb3e958f6cb2ad7d9b90ee97e81a4185.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 100, + 302, + 233, + 385 + ], + "blocks": [ + { + "bbox": [ + 102, + 212, + 113, + 221 + ], + "lines": [ + { + "bbox": [ + 102, + 212, + 113, + 221 + ], + "spans": [ + { + "bbox": [ + 102, + 212, + 113, + 221 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 219, + 212, + 230, + 221 + ], + "lines": [ + { + "bbox": [ + 219, + 212, + 230, + 221 + ], + "spans": [ + { + "bbox": [ + 219, + 212, + 230, + 221 + ], + "type": "text", + "content": "(b)" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 46, + 232, + 287, + 280 + ], + "lines": [ + { + "bbox": [ + 46, + 232, + 287, + 280 + ], + "spans": [ + { + "bbox": [ + 46, + 232, + 287, + 280 + ], + "type": "text", + "content": "Table 2: Comparison to other OAD methods on (a) THUMOS'14 [19] dataset and (b) TVSeries dataset [7]. Results using the backbone pre-trained using Activitynet [17] and Kinetics [2] are shown." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 100, + 302, + 233, + 385 + ], + "lines": [ + { + "bbox": [ + 100, + 302, + 233, + 385 + ], + "spans": [ + { + "bbox": [ + 100, + 302, + 233, + 385 + ], + "type": "table", + "html": "
MethodmAP (%)
OadTR[36]31.8
LSTR[40]31.6
TeSTra[43]31.2
Ours37.1
", + "image_path": "963d2acfcafe4caea54f290014d31cf2702cf05e1d5cee805a73e77cb457101d.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 397, + 287, + 421 + ], + "lines": [ + { + "bbox": [ + 46, + 397, + 287, + 421 + ], + "spans": [ + { + "bbox": [ + 46, + 397, + 287, + 421 + ], + "type": "text", + "content": "Table 3: Comparison to other OAD methods on FineAction dataset [24]." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "text" + }, + { + "type": "image", + "bbox": [ + 69, + 445, + 255, + 610 + ], + "blocks": [ + { + "bbox": [ + 69, + 445, + 255, + 610 + ], + "lines": [ + { + "bbox": [ + 69, + 445, + 255, + 610 + ], + "spans": [ + { + "bbox": [ + 69, + 445, + 255, + 610 + ], + "type": "image", + "image_path": "3d811e11e5913d2d50001872ab829f7996a5a52deeeb9854715dd1190357a0a0.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 620, + 287, + 693 + ], + "lines": [ + { + "bbox": [ + 46, + 620, + 287, + 693 + ], + "spans": [ + { + "bbox": [ + 46, + 620, + 287, + 693 + ], + "type": "text", + "content": "Figure 3: Attention heatmap (top) and its specific values (bottom) of the transformer encoders in OadTR [36]. For the heatmap calculation, all the attention values in the encoder (of every layer and head) are collected for the entire test set input which are then averaged out over the heads. The above shows the collected values after normalization." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "bbox": [ + 306, + 72, + 494, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 494, + 85 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 494, + 85 + ], + "type": "text", + "content": "5.2. Why is RNN adequate for the task?" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 90, + 545, + 197 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 90, + 545, + 197 + ], + "spans": [ + { + "bbox": [ + 304, + 90, + 545, + 197 + ], + "type": "text", + "content": "The prevailing reasoning behind the lower performance of RNNs is that they struggle with learning long-range dependencies. This is often attributed to training difficulties such as gradient vanishing that can arise when processing prolonged sequences. Therefore, recent works have been using transformers for OAD as they are particularly proficient at capturing long-term dependencies. However, it is worth asking how much temporal information is actually needed for OAD." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 202, + 546, + 382 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 202, + 546, + 382 + ], + "spans": [ + { + "bbox": [ + 304, + 202, + 546, + 382 + ], + "type": "text", + "content": "What do Transformers Actually See? Inspired by the recent success of transformer models in OAD, we analyzed the attention weights within the transformer multi-head attention to gain insights into the model's decision-making process. The visualization results are presented in Figure 3. As evident from the heat map and the graph, the transformer model predominantly focuses on the recent and neighboring frames, indicating the recent input's dominant influence on the prediction. Surprisingly, despite the transformer's intended capability of capturing long-term dependencies, the model mainly relies on the recent frames for making the current frame prediction. Our analysis reinforces the argument that RNN's inductive bias, which prioritizes the current input while retaining meaningful temporal information from the past, is well suited for the task." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 388, + 546, + 591 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 388, + 546, + 591 + ], + "spans": [ + { + "bbox": [ + 304, + 388, + 546, + 591 + ], + "type": "text", + "content": "Optimal Length of Temporal Information. Figure 4 shows the performance of our model with varying clip lengths using the proposed methodology. As our methodology trains the model with the loss computed at the end of the clip, the graph shows the trade-off between providing more temporal information and ignoring the supervision of the earlier steps. The figure shows that a saturation point is reached at 32 seconds and providing more information than 32 seconds does not improve the performance. To the commonly held belief that the RNN does not benefit from prolonged sequence length, there exists a model's maximum capacity. It is important to note, however, that RNN's capacity is already enough to perform well on the OAD task, validated by the promising performances shown in Section 5.1. A slight drop in performance after 32 seconds is a result of RNN not being able to use temporal information beyond a certain point and much supervision lost during training." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 599, + 459, + 612 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 599, + 459, + 612 + ], + "spans": [ + { + "bbox": [ + 306, + 599, + 459, + 612 + ], + "type": "text", + "content": "5.3. What is the optimal weight?" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 618, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 618, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 618, + 545, + 713 + ], + "type": "text", + "content": "Our work shows that the uniform weights put on computed loss at each time-step hinders the effective training of the RNNs. To make the most use of the finding, we experimented with varying weight choices " + }, + { + "bbox": [ + 304, + 618, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\alpha_{t}" + }, + { + "bbox": [ + 304, + 618, + 545, + 713 + ], + "type": "text", + "content": " in (1) at each time step. Different choices of weights including uniform, linearly increasing, exponentially increasing, learnable, and step function, are experimented. The results are shown in Table 4a. The results indicate that assigning uniform" + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10346" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 66, + 92, + 255, + 228 + ], + "blocks": [ + { + "bbox": [ + 78, + 72, + 261, + 83 + ], + "lines": [ + { + "bbox": [ + 78, + 72, + 261, + 83 + ], + "spans": [ + { + "bbox": [ + 78, + 72, + 261, + 83 + ], + "type": "text", + "content": "Effect of Hidden State Duration on THUMOS 14" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 66, + 92, + 255, + 228 + ], + "lines": [ + { + "bbox": [ + 66, + 92, + 255, + 228 + ], + "spans": [ + { + "bbox": [ + 66, + 92, + 255, + 228 + ], + "type": "image", + "image_path": "54190922a5acbd615dde3e21acd069b8799e42f9ff1968863e756a1de2a561b7.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 239, + 287, + 263 + ], + "lines": [ + { + "bbox": [ + 46, + 239, + 287, + 263 + ], + "spans": [ + { + "bbox": [ + 46, + 239, + 287, + 263 + ], + "type": "text", + "content": "Figure 4: Effect of varying the length of the clip " + }, + { + "bbox": [ + 46, + 239, + 287, + 263 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 46, + 239, + 287, + 263 + ], + "type": "text", + "content": " during training." + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 285, + 289, + 538 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 285, + 289, + 538 + ], + "spans": [ + { + "bbox": [ + 46, + 285, + 289, + 538 + ], + "type": "text", + "content": "weights to the loss computed at each time-step results in the worst performance, which is consistent with the findings discussed in the paper that this conventional approach impedes the effective training of the model. Applying linearly increasing weights performs better than assigning uniform weights because it places less emphasis on early-stage predictions. The next best performing choice is exponentially increasing weights, which heavily emphasizes the loss computed at later stages. The next best performing weight choice is learnable weights. For this experimental setup, learnable embeddings of size " + }, + { + "bbox": [ + 46, + 285, + 289, + 538 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 46, + 285, + 289, + 538 + ], + "type": "text", + "content": " (length of the clip) were trained. When computing the loss, we apply softmax activation to the learnable weights, which are then multiplied by their corresponding loss at their time steps. This approach shows even better performance than exponentially increasing weights. The best-performing choice of weight is step-function which uses only the loss computed at the end. This results in the best performance as the loss associated with predictions using the informative hidden state best resemble the dominant predictions made at the inference stage." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 559, + 198, + 571 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 559, + 198, + 571 + ], + "spans": [ + { + "bbox": [ + 47, + 559, + 198, + 571 + ], + "type": "text", + "content": "5.4. Effectiveness of the method" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 582, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 287, + 715 + ], + "type": "text", + "content": "Table 4b shows the result of our model with and without the proposed non-uniform weights. We can observe that there is a " + }, + { + "bbox": [ + 46, + 582, + 287, + 715 + ], + "type": "inline_equation", + "content": "5\\%" + }, + { + "bbox": [ + 46, + 582, + 287, + 715 + ], + "type": "text", + "content": " mAP increase by using our proposed methodology. In addition, we also experiment with our proposed methodology using the transformer architecture. For the experiment, we adopt the transformer encoder from OadTR and set the encoding layers to 3 and the number of heads to 8 which is the default setting in the publicly available code. We observe that the performance increases from 63.0 to " + }, + { + "bbox": [ + 46, + 582, + 287, + 715 + ], + "type": "inline_equation", + "content": "64.9\\%" + }, + { + "bbox": [ + 46, + 582, + 287, + 715 + ], + "type": "text", + "content": " mAP with a " + }, + { + "bbox": [ + 46, + 582, + 287, + 715 + ], + "type": "inline_equation", + "content": "1.9\\%" + }, + { + "bbox": [ + 46, + 582, + 287, + 715 + ], + "type": "text", + "content": " mAP increase using our proposed methodology." + } + ] + } + ], + "index": 5 + }, + { + "type": "table", + "bbox": [ + 307, + 71, + 422, + 144 + ], + "blocks": [ + { + "bbox": [ + 307, + 71, + 422, + 144 + ], + "lines": [ + { + "bbox": [ + 307, + 71, + 422, + 144 + ], + "spans": [ + { + "bbox": [ + 307, + 71, + 422, + 144 + ], + "type": "table", + "html": "
Weight TypemAP (%)
Uniform66.4
Linear68.6
Exponential69.8
Learnable70.8
Step-Function71.8
", + "image_path": "2c23386c7975ac229e8195f510dce889007c97b625c799f66dc6410c05cfc939.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "table_body" + } + ], + "index": 6 + }, + { + "type": "table", + "bbox": [ + 424, + 80, + 547, + 135 + ], + "blocks": [ + { + "bbox": [ + 359, + 150, + 372, + 160 + ], + "lines": [ + { + "bbox": [ + 359, + 150, + 372, + 160 + ], + "spans": [ + { + "bbox": [ + 359, + 150, + 372, + 160 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 424, + 80, + 547, + 135 + ], + "lines": [ + { + "bbox": [ + 424, + 80, + 547, + 135 + ], + "spans": [ + { + "bbox": [ + 424, + 80, + 547, + 135 + ], + "type": "table", + "html": "
Method
TransformerMiniROAD
Uniform Weight63.066.4
Proposed64.971.8
", + "image_path": "9058fe8319b4d7756e7aaf39484bdd03908a22f57c96d388dfebe4f5816ef234.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "table_body" + } + ], + "index": 8 + }, + { + "type": "table", + "bbox": [ + 307, + 243, + 545, + 333 + ], + "blocks": [ + { + "bbox": [ + 478, + 150, + 490, + 159 + ], + "lines": [ + { + "bbox": [ + 478, + 150, + 490, + 159 + ], + "spans": [ + { + "bbox": [ + 478, + 150, + 490, + 159 + ], + "type": "text", + "content": "(b)" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 305, + 171, + 547, + 230 + ], + "lines": [ + { + "bbox": [ + 305, + 171, + 547, + 230 + ], + "spans": [ + { + "bbox": [ + 305, + 171, + 547, + 230 + ], + "type": "text", + "content": "Table 4: (a) Result of applying different weights " + }, + { + "bbox": [ + 305, + 171, + 547, + 230 + ], + "type": "inline_equation", + "content": "\\alpha_{t}" + }, + { + "bbox": [ + 305, + 171, + 547, + 230 + ], + "type": "text", + "content": " in (1). Otherwise stated, Step-Function is the default choice in our paper which only uses the loss computed at the end of the clip. (b) Result of applying the proposed weights on the transformer-based model and on our model." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 307, + 243, + 545, + 333 + ], + "lines": [ + { + "bbox": [ + 307, + 243, + 545, + 333 + ], + "spans": [ + { + "bbox": [ + 307, + 243, + 545, + 333 + ], + "type": "table", + "html": "
MethodOF. Comp.RGB Feat.OF. Feat.Model FPSOverall FPSmAP (%)
TRN14320.562.1
OadTR14520.565.2
LSTR28.838321918721.269.5
TeSTra16920.971.2
Ours3730023.871.8
", + "image_path": "d4119cb2924a78452f556a3548b87b6c12c274a9622ae848d9f1d7d6d527286a.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_body" + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 345, + 546, + 406 + ], + "lines": [ + { + "bbox": [ + 305, + 345, + 546, + 406 + ], + "spans": [ + { + "bbox": [ + 305, + 345, + 546, + 406 + ], + "type": "text", + "content": "Table 5: Runtime Comparison of OAD methods on THU-MOS'14 dataset with flow features extracted using TV-L1 [41] algorithm. OF. Comp., RGB Feat., and OF. Feat. are the speed of extracting optical flows, rgb features, and optical flow features respectively, measured in FPS." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 420, + 370, + 431 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 420, + 370, + 431 + ], + "spans": [ + { + "bbox": [ + 306, + 420, + 370, + 431 + ], + "type": "text", + "content": "5.5. Runtime" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 439, + 545, + 691 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 439, + 545, + 691 + ], + "spans": [ + { + "bbox": [ + 304, + 439, + 545, + 691 + ], + "type": "text", + "content": "Efficiency is a critical aspect of the online nature of the OAD task. To assess efficiency, we compare MiniROAD's runtime with recent methods in frames per second (FPS) using videos from the THUMOS'14 dataset on a system with a single RTX3090 GPU. The results in Table 5 demonstrate that our model's lightweight RNN architecture is very efficient, running about 200 times faster than previous methods. However, it is worth noting that the model's speed is not the final speed, as the input of the OAD model requires the extraction of visual and motion features. As illustrated in Table 5, computing optical flow accounts for the majority of the computation time. The end-to-end speed, which encompasses the speed after computing optical flows, extracting visual and motion features, and passing through the model, is reported as Overall FPS in the table. Although extracting optical flow acts as a bottleneck, the efficiency of our model yields 2.9 gains in FPS overall. These gains in overall speed are further improved when a faster optical flow computing algorithm is used. To demonstrate the efficacy of this approach, we also test using the NVIDIA Optical Flow " + }, + { + "bbox": [ + 304, + 439, + 545, + 691 + ], + "type": "inline_equation", + "content": "\\mathrm{SDK}^1" + }, + { + "bbox": [ + 304, + 439, + 545, + 691 + ], + "type": "text", + "content": " (NVOFA) for faster optical flow computa" + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 317, + 702, + 465, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 702, + 465, + 712 + ], + "spans": [ + { + "bbox": [ + 317, + 702, + 465, + 712 + ], + "type": "text", + "content": "1https://developer.nvidia.com/opticalflow-sdk" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10347" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 82, + 70, + 511, + 230 + ], + "blocks": [ + { + "bbox": [ + 82, + 70, + 511, + 230 + ], + "lines": [ + { + "bbox": [ + 82, + 70, + 511, + 230 + ], + "spans": [ + { + "bbox": [ + 82, + 70, + 511, + 230 + ], + "type": "table", + "html": "
MethodPre-TrainmAP@τ0Average
0.250.50.7511.251.51.752
RED [14]45.342.139.637.535.834.433.232.137.5
TRN [39]45.142.440.739.137.736.435.334.338.9
TTM [35]45.943.742.441.039.939.437.937.340.9
LAP-Net [29]49.047.445.343.241.339.738.337.042.6
OadTR [36]ANet1.350.249.348.146.845.343.942.441.145.9
LSTR [40]--------50.1
GateHUB [3]--------54.2
TeSTra [43]64.761.858.755.753.251.149.247.855.3
Ours65.463.360.557.454.851.949.747.756.3
TTM [35]46.845.544.643.641.941.140.438.742.8
LSTR [36]60.458.656.053.350.948.947.145.752.6
OadTR [36]K40059.858.556.654.652.650.548.646.853.5
TeSTra [43]66.263.560.557.454.852.650.548.956.8
Ours68.566.363.560.757.955.653.551.459.7
", + "image_path": "a3efae55b464afa718fc8df08e78d6465d3cac5430dbd8dab126e73bae13b4b3.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 48, + 275, + 287, + 365 + ], + "blocks": [ + { + "bbox": [ + 46, + 241, + 546, + 266 + ], + "lines": [ + { + "bbox": [ + 46, + 241, + 546, + 266 + ], + "spans": [ + { + "bbox": [ + 46, + 241, + 546, + 266 + ], + "type": "text", + "content": "Table 6: Action Anticipation Results on THUMOS'14 dataset with feature extractor pretrained with Activitynet (top) and Kinetics (bottom)." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 48, + 275, + 287, + 365 + ], + "lines": [ + { + "bbox": [ + 48, + 275, + 287, + 365 + ], + "spans": [ + { + "bbox": [ + 48, + 275, + 287, + 365 + ], + "type": "table", + "html": "
MethodOF. Comp.RGB Feat.OF. Feat.Model FPSOverall FPSmAP (%)
TRN†14366.061.6
OADTR†14566.363.3
LSTR†1K38321918773.867.1
TeSTra16970.967.3
Ours3730012268.4
", + "image_path": "4331211540c426377d4302aff61ef9d212c9fbe6dd7f2c725e6e34acc1ed386f.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 376, + 287, + 424 + ], + "lines": [ + { + "bbox": [ + 46, + 376, + 287, + 424 + ], + "spans": [ + { + "bbox": [ + 46, + 376, + 287, + 424 + ], + "type": "text", + "content": "Table 7: Comparison to other OAD methods on THU-MOS'14 dataset with flow features extracted using NVIDIA OPTICAL FLOW. " + }, + { + "bbox": [ + 46, + 376, + 287, + 424 + ], + "type": "inline_equation", + "content": "\\dagger" + }, + { + "bbox": [ + 46, + 376, + 287, + 424 + ], + "type": "text", + "content": " was reproduced by us. All the values indicate the speed measured in FPS." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 437, + 287, + 568 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 437, + 287, + 568 + ], + "spans": [ + { + "bbox": [ + 46, + 437, + 287, + 568 + ], + "type": "text", + "content": "tion, which runs at around 1K FPS. By utilizing the faster flow algorithm, our model runs at 122 FPS which is 1.72 times faster than the state-of-the-art model. Although there is a degradation in the final performance compared to the traditionally used flow algorithm, this highlights the availability of an alternative approach that can deliver faster end-to-end speed while balancing performance and speed trade-offs. The significant increase in end-to-end speed when using the faster optical flow algorithm indicates that additional increases can be gained with RGB-only inputs, leaving open opportunities for future work." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 575, + 162, + 588 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 575, + 162, + 588 + ], + "spans": [ + { + "bbox": [ + 47, + 575, + 162, + 588 + ], + "type": "text", + "content": "5.6. Action Anticipation" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "type": "text", + "content": "As our methodology is also applicable to other online tasks, we extend our method to Action Anticipation, which is a task of anticipating upcoming actions using the histories. Instead of predicting the current time frame, the model is trained to predict the next upcoming actions every 0.25 seconds up to 2 seconds. Table 6 shows the results of predictions at each of that time-step. It shows that our method performs favorably to the other methods with " + }, + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "type": "inline_equation", + "content": "1\\%" + }, + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "type": "text", + "content": " mAP gain using activitynet pretrained backbone and " + }, + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "type": "inline_equation", + "content": "2.9\\%" + }, + { + "bbox": [ + 46, + 594, + 288, + 715 + ], + "type": "text", + "content": " mAP gain using kinetics pretrained backbone over the previous state" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 278, + 545, + 314 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 278, + 545, + 314 + ], + "spans": [ + { + "bbox": [ + 304, + 278, + 545, + 314 + ], + "type": "text", + "content": "of-the-art. While our methodology was initially designed for OAD, its applicability extends beyond OAD and can be used for other similar tasks." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 326, + 378, + 338 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 326, + 378, + 338 + ], + "spans": [ + { + "bbox": [ + 306, + 326, + 378, + 338 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 346, + 545, + 477 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 346, + 545, + 477 + ], + "spans": [ + { + "bbox": [ + 304, + 346, + 545, + 477 + ], + "type": "text", + "content": "We revisit RNN for online action detection and show its potential in dealing with the task. We identify the training-inference discrepancy as a primary cause of the lower performance of RNNs and address the issue by introducing non-uniform weights to the loss computed at each timesteps. We demonstrate the effectiveness of our proposed method using MiniROAD, a minimal RNN-based OAD model. MiniROAD achieves equal or better accuracy than the existing best method on challenging datasets, with a significant increase in efficiency. With the faster NVOFA, MiniROAD runs at an impressive 122 FPS." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 478, + 545, + 562 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 478, + 545, + 562 + ], + "spans": [ + { + "bbox": [ + 304, + 478, + 545, + 562 + ], + "type": "text", + "content": "We note that recent OAD methods rely heavily on optical flows, which impede end-to-end speed. While faster optical flow algorithms like NVOFA can mitigate this issue, flow-free OAD remains an open yet challenging problem. By highlighting the suitability of RNNs for processing streaming videos, we hope to pave the way for further advancements and shed light on developing more efficient models." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 574, + 408, + 586 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 574, + 408, + 586 + ], + "spans": [ + { + "bbox": [ + 306, + 574, + 408, + 586 + ], + "type": "text", + "content": "Acknowledgements" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 545, + 714 + ], + "type": "text", + "content": "This work was supported by Samsung Electronics Co., Ltd. (Mobile eXperience Business), Yonsei University Artificial Intelligence Graduate School Program under Grant 2020-0-01361, and by the Institute of Information & communications Technology Planning & Evaluation (IITP) grant funded by the Korea government(MSIT) (No.2022-0-00124, Development of Artificial Intelligence Technology for Self-Improving Competency-Aware Learning Capabilities). The work of Joungbin was in part supported by the Hyundai Motor Chung Mong-Koo Foundation." + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10348" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "type": "text", + "content": "[1] Anurag Arnab, Mostafa Dehghani, Georg Heigold, Chen Sun, Mario Lučić, and Cordelia Schmid. Vivit: A video vision transformer. In IEEE International Conference on Computer Vision (ICCV), pages 6836-6846, 2021. 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 137, + 288, + 180 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 137, + 288, + 180 + ], + "spans": [ + { + "bbox": [ + 53, + 137, + 288, + 180 + ], + "type": "text", + "content": "[2] Joao Carreira and Andrew Zisserman. Quo vadis, action recognition? a new model and the kinetics dataset. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 6299-6308, 2017. 5, 6" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 182, + 288, + 236 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 182, + 288, + 236 + ], + "spans": [ + { + "bbox": [ + 53, + 182, + 288, + 236 + ], + "type": "text", + "content": "[3] Junwen Chen, Gaurav Mittal, Ye Yu, Yu Kong, and Mei Chen. Gatehub: Gated history unit with background suppression for online action detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2022. 3, 4, 5, 6, 8" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 238, + 288, + 293 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 238, + 288, + 293 + ], + "spans": [ + { + "bbox": [ + 53, + 238, + 288, + 293 + ], + "type": "text", + "content": "[4] Kyunghyun Cho, Bart Van Merrienboer, Caglar Gulcehre, Dzmitry Bahdanau, Fethi Bougares, Holger Schwenk, and Yoshua Bengio. Learning phrase representations using rnn encoder-decoder for statistical machine translation. arXiv preprint arXiv:1406.1078, 2014. 2" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 294, + 288, + 338 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 294, + 288, + 338 + ], + "spans": [ + { + "bbox": [ + 53, + 294, + 288, + 338 + ], + "type": "text", + "content": "[5] Junyoung Chung, Caglar Gulcehre, KyungHyun Cho, and Yoshua Bengio. Empirical evaluation of gated recurrent neural networks on sequence modeling. arXiv preprint arXiv:1412.3555, 2014. 1, 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 339, + 288, + 373 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 339, + 288, + 373 + ], + "spans": [ + { + "bbox": [ + 53, + 339, + 288, + 373 + ], + "type": "text", + "content": "[6] MMAction2 Contributors. Openmmlab's next generation video understanding toolbox and benchmark. https://github.com/open-mmlab/mmaction2, 2020.5" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 374, + 288, + 418 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 374, + 288, + 418 + ], + "spans": [ + { + "bbox": [ + 53, + 374, + 288, + 418 + ], + "type": "text", + "content": "[7] Roeland De Geest, Efstratios Gavves, Amir Ghodrati, Zhenyang Li, Cees Snoek, and Tinne Tuytelaars. Online action detection. In European Conference on Computer Vision (ECCV), pages 269-284. Springer, 2016. 1, 2, 4, 5, 6" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 419, + 288, + 463 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 419, + 288, + 463 + ], + "spans": [ + { + "bbox": [ + 53, + 419, + 288, + 463 + ], + "type": "text", + "content": "[8] Roeland De Geest and Tinne Tuytelaars. Modeling temporal structure with lstm for online action detection. In IEEE Winter Conference on Applications of Computer Vision (WACV), pages 1549-1557. IEEE, 2018. 2" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 464, + 288, + 508 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 464, + 288, + 508 + ], + "spans": [ + { + "bbox": [ + 53, + 464, + 288, + 508 + ], + "type": "text", + "content": "[9] Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirectional transformers for language understanding. arXiv preprint arXiv:1810.04805, 2018. 1, 3" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 510, + 287, + 575 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 510, + 287, + 575 + ], + "spans": [ + { + "bbox": [ + 48, + 510, + 287, + 575 + ], + "type": "text", + "content": "[10] Alexey Dosovitskiy, Lucas Beyer, Alexander Kolesnikov, Dirk Weissenborn, Xiaohua Zhai, Thomas Unterthiner, Mostafa Dehghani, Matthias Minderer, Georg Heigold, Sylvain Gelly, et al. An image is worth 16x16 words: Transformers for image recognition at scale. arXiv preprint arXiv:2010.11929, 2020. 1, 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 577, + 287, + 598 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 577, + 287, + 598 + ], + "spans": [ + { + "bbox": [ + 48, + 577, + 287, + 598 + ], + "type": "text", + "content": "[11] Jeffrey L Elman. Finding structure in time. Cognitive science, 14(2):179-211, 1990. 1" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 600, + 287, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 600, + 287, + 644 + ], + "spans": [ + { + "bbox": [ + 48, + 600, + 287, + 644 + ], + "type": "text", + "content": "[12] Hyunjun Eun, Jinyoung Moon, Jongyoul Park, Chanho Jung, and Changick Kim. Learning to discriminate information for online action detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2020. 2, 6" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 646, + 287, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 646, + 287, + 678 + ], + "spans": [ + { + "bbox": [ + 48, + 646, + 287, + 678 + ], + "type": "text", + "content": "[13] Hyunjun Eun, Jinyoung Moon, Jongyoul Park, Chanho Jung, and Changick Kim. Temporal filtering networks for online action detection. Pattern Recognition, 111:107695, 2021. 6" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 680, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 680, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 680, + 287, + 713 + ], + "type": "text", + "content": "[14] Jiyang Gao, Zhenheng Yang, and Ram Nevatia. Red: Reinforced encoder-decoder networks for action anticipation. arXiv preprint arXiv:1707.04818, 2017. 2, 6, 8" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 30, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 127 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 127 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 127 + ], + "type": "text", + "content": "[15] Mingfei Gao, Yingbo Zhou, Ran Xu, Richard Socher, and Caiming Xiong. Woad: Weakly supervised online action detection in untrimmed videos. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 1915-1923, 2021. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 129, + 545, + 162 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 129, + 545, + 162 + ], + "spans": [ + { + "bbox": [ + 307, + 129, + 545, + 162 + ], + "type": "text", + "content": "[16] Albert Gu, Karan Goel, and Christopher Ré. Efficiently modeling long sequences with structured state spaces. arXiv preprint arXiv:2111.00396, 2021. 3" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 163, + 545, + 217 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 163, + 545, + 217 + ], + "spans": [ + { + "bbox": [ + 308, + 163, + 545, + 217 + ], + "type": "text", + "content": "[17] Fabian Caba Heilbron, Victor Escorcia, Bernard Ghanem, and Juan Carlos Niebles. Activitynet: A large-scale video benchmark for human activity understanding. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 961-970. IEEE, 2015. 5, 6" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 220, + 545, + 250 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 220, + 545, + 250 + ], + "spans": [ + { + "bbox": [ + 308, + 220, + 545, + 250 + ], + "type": "text", + "content": "[18] Sepp Hochreiter and Jürgen Schmidhuber. Long short-term memory. Neural computation, 9(8):1735-1780, 1997. 1, 2, 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 253, + 545, + 307 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 253, + 545, + 307 + ], + "spans": [ + { + "bbox": [ + 308, + 253, + 545, + 307 + ], + "type": "text", + "content": "[19] Haroon Idrees, Amir R Zamir, Yu-Gang Jiang, Alex Gorban, Ivan Laptev, Rahul Sukthankar, and Mubarak Shah. The thumos challenge on action recognition for videos \"in the wild\". Computer Vision and Image Understanding(CVIU), 155:1-23, 2017. 4, 6" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 309, + 545, + 363 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 309, + 545, + 363 + ], + "spans": [ + { + "bbox": [ + 308, + 309, + 545, + 363 + ], + "type": "text", + "content": "[20] Jinkyu Kim, Teruhisa Misu, Yi-Ting Chen, Ashish Tawari, and John Canny. Grounding human-to-vehicle advice for self-driving vehicles. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 10591–10599, 2019. 1" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 365, + 545, + 407 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 365, + 545, + 407 + ], + "spans": [ + { + "bbox": [ + 308, + 365, + 545, + 407 + ], + "type": "text", + "content": "[21] Young Hwi Kim, Seonghyeon Nam, and Seon Joo Kim. Temporally smooth online action detection using cycle-consistent future anticipation. Pattern Recognition, 116:107954, 2021. 2, 6" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 410, + 545, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 410, + 545, + 453 + ], + "spans": [ + { + "bbox": [ + 308, + 410, + 545, + 453 + ], + "type": "text", + "content": "[22] Serkan Kiranyaz, Onur Avci, Osama Abdeljaber, Turker Ince, Moncef Gabbouj, and Daniel J Inman. 1d convolutional neural networks and applications: A survey. Mechanical systems and signal processing, 151:107398, 2021. 3" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 456, + 545, + 488 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 456, + 545, + 488 + ], + "spans": [ + { + "bbox": [ + 308, + 456, + 545, + 488 + ], + "type": "text", + "content": "[23] Zachary C Lipton, John Berkowitz, and Charles Elkan. A critical review of recurrent neural networks for sequence learning. arXiv preprint arXiv:1506.00019, 2015. 1, 2" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 490, + 545, + 532 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 490, + 545, + 532 + ], + "spans": [ + { + "bbox": [ + 308, + 490, + 545, + 532 + ], + "type": "text", + "content": "[24] Yi Liu, Limin Wang, Yali Wang, Xiao Ma, and Yu Qiao. Fineaction: A fine-grained video dataset for temporal action localization. IEEE Transactions on Image Processing, 2022, 4, 6" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 535, + 545, + 578 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 535, + 545, + 578 + ], + "spans": [ + { + "bbox": [ + 308, + 535, + 545, + 578 + ], + "type": "text", + "content": "[25] Antonio Orvieto, Samuel L Smith, Albert Gu, Anushan Fernando, Caglar Gulcehre, Razvan Pascanu, and Soham De. Resurrecting recurrent neural networks for long sequences. arXiv preprint arXiv:2303.06349, 2023. 3" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 580, + 545, + 633 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 580, + 545, + 633 + ], + "spans": [ + { + "bbox": [ + 308, + 580, + 545, + 633 + ], + "type": "text", + "content": "[26] Guansong Pang, Cheng Yan, Chunhua Shen, Anton van den Hengel, and Xiao Bai. Self-trained deep ordinal regression for end-to-end video anomaly detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 12173-12182, 2020. 1" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 635, + 545, + 678 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 635, + 545, + 678 + ], + "spans": [ + { + "bbox": [ + 308, + 635, + 545, + 678 + ], + "type": "text", + "content": "[27] Hyunjong Park, Jongyoun Noh, and Bumsub Ham. Learning memory-guided normality for anomaly detection. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 14372-14381, 2020. 1" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 308, + 680, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 680, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 308, + 680, + 545, + 713 + ], + "type": "text", + "content": "[28] Bo Peng, Eric Alcaide, Quentin Anthony, Alon Albalak, Samuel Arcadinho, Huanqi Cao, Xin Cheng, Michael Chung, Matteo Grella, Kranthi Kiran GV, et al. Rwkv:" + } + ] + } + ], + "index": 29 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "10349" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "spans": [ + { + "bbox": [ + 66, + 72, + 287, + 95 + ], + "type": "text", + "content": "Reinventing rnns for the transformer era. arXiv preprint arXiv:2305.13048, 2023. 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 97, + 287, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 97, + 287, + 140 + ], + "spans": [ + { + "bbox": [ + 48, + 97, + 287, + 140 + ], + "type": "text", + "content": "[29] Sanqing Qu, Guang Chen, Dan Xu, Jinhu Dong, Fan Lu, and Alois Knoll. Lap-net: Adaptive features sampling via learning action progression for online action detection. arXiv preprint arXiv:2011.07915, 2020. 6, 8" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 143, + 287, + 175 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 143, + 287, + 175 + ], + "spans": [ + { + "bbox": [ + 48, + 143, + 287, + 175 + ], + "type": "text", + "content": "[30] Mike Schuster and Kuldip K Paliwal. Bidirectional recurrent neural networks. IEEE transactions on Signal Processing, 45(11):2673-2681, 1997. 1, 4" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 178, + 287, + 232 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 178, + 287, + 232 + ], + "spans": [ + { + "bbox": [ + 48, + 178, + 287, + 232 + ], + "type": "text", + "content": "[31] Tianmin Shu, Dan Xie, Brandon Rothrock, Sinisa Todorovic, and Song Chun Zhu. Joint inference of groups, events and human roles in aerial videos. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 4576-4584, 2015. 1" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 235, + 287, + 277 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 235, + 287, + 277 + ], + "spans": [ + { + "bbox": [ + 48, + 235, + 287, + 277 + ], + "type": "text", + "content": "[32] Karen Simonyan and Andrew Zisserman. Two-stream convolutional networks for action recognition in videos. Conference on Neural Information Processing Systems (NeurIPS), 27, 2014. 5" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 281, + 287, + 324 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 281, + 287, + 324 + ], + "spans": [ + { + "bbox": [ + 48, + 281, + 287, + 324 + ], + "type": "text", + "content": "[33] Ashish Vaswani, Noam Shazeer, Niki Parmar, Jakob Uszkoreit, Llion Jones, Aidan N Gomez, Lukasz Kaiser, and Illia Polosukhin. Attention is all you need. Conference on Neural Information Processing Systems (NeurIPS), 30, 2017. 1, 3" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 327, + 287, + 380 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 327, + 287, + 380 + ], + "spans": [ + { + "bbox": [ + 48, + 327, + 287, + 380 + ], + "type": "text", + "content": "[34] Limin Wang, Yuanjun Xiong, Zhe Wang, Yu Qiao, Dahua Lin, Xiaou Tang, and Luc Van Gool. Temporal segment networks: Towards good practices for deep action recognition. In European Conference on Computer Vision (ECCV), pages 20-36. Springer, 2016. 5" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 384, + 287, + 426 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 384, + 287, + 426 + ], + "spans": [ + { + "bbox": [ + 48, + 384, + 287, + 426 + ], + "type": "text", + "content": "[35] Wen Wang, Xiaojiang Peng, Yanzhou Su, Yu Qiao, and Jian Cheng. Tpp: Temporal transformer with progressive prediction for efficient action anticipation. Neurocomputing, 438:270-279, 2021. 8" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 429, + 287, + 473 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 429, + 287, + 473 + ], + "spans": [ + { + "bbox": [ + 48, + 429, + 287, + 473 + ], + "type": "text", + "content": "[36] Xiang Wang, Shiwei Zhang, Zhiwu Qing, Yuanjie Shao, Zhengrong Zuo, Changxin Gao, and Nong Sang. Oadtr: Online action detection with transformers. IEEE International Conference on Computer Vision (ICCV), 2021. 2, 5, 6, 8" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 475, + 287, + 506 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 475, + 287, + 506 + ], + "spans": [ + { + "bbox": [ + 48, + 475, + 287, + 506 + ], + "type": "text", + "content": "[37] Paul J Werbos. Backpropagation through time: what it does and how to do it. Proceedings of the IEEE, 78(10):1550-1560, 1990. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 510, + 287, + 575 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 510, + 287, + 575 + ], + "spans": [ + { + "bbox": [ + 48, + 510, + 287, + 575 + ], + "type": "text", + "content": "[38] Chao-Yuan Wu, Yanghao Li, Karttikeya Mangalam, Haoqi Fan, Bo Xiong, Jitendra Malik, and Christoph Feichtenhofer. Memvit: Memory-augmented multiscale vision transformer for efficient long-term video recognition. In IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pages 13587-13597, 2022. 3" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 578, + 287, + 621 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 578, + 287, + 621 + ], + "spans": [ + { + "bbox": [ + 48, + 578, + 287, + 621 + ], + "type": "text", + "content": "[39] Mingze Xu, Mingfei Gao, Yi-Ting Chen, Larry S. Davis, and David J. Crandall. Temporal recurrent networks for online action detection. In IEEE International Conference on Computer Vision (ICCV), 2019. 2, 5, 6, 8" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 624, + 287, + 677 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 624, + 287, + 677 + ], + "spans": [ + { + "bbox": [ + 48, + 624, + 287, + 677 + ], + "type": "text", + "content": "[40] Mingze Xu, Yuanjun Xiong, Hao Chen, Xinyu Li, Wei Xia, Zhuowen Tu, and Stefano Soatto. Long short-term transformer for online action detection. In Conference on Neural Information Processing Systems (NeurIPS), 2021. 2, 4, 5, 6, 8" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 680, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 680, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 680, + 287, + 713 + ], + "type": "text", + "content": "[41] Christopher Zach, Thomas Pock, and Horst Bischof. A duality based approach for realtime tv-l 1 optical flow. In Pattern Recognition, pages 214-223. Springer, 2007. 7" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 150 + ], + "type": "list", + "angle": 0, + "index": 17, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "text", + "content": "[42] Peisen Zhao, Lingxi Xie, Ya Zhang, Yanfeng Wang, and Qi Tian. Privileged knowledge distillation for online action detection. arXiv preprint arXiv:2011.09158, 2020. 6" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 107, + 545, + 150 + ], + "type": "text", + "content": "[43] Yue Zhao and Philipp Krahenbuhl. Real-time online video detection with temporal smoothing transformers. In European Conference on Computer Vision (ECCV), 2022. 3, 4, 5, 6, 8" + } + ] + } + ], + "index": 16 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "10350" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/21f6bf16-a75f-4e22-8ec8-d9aabd4e98e3_content_list.json b/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/21f6bf16-a75f-4e22-8ec8-d9aabd4e98e3_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..566e53ad68b79077d05e2a39eb61310201c5d94d --- /dev/null +++ b/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/21f6bf16-a75f-4e22-8ec8-d9aabd4e98e3_content_list.json @@ -0,0 +1,1920 @@ +[ + { + "type": "text", + "text": "Minimal Solutions to Generalized Three-View Relative Pose Problem", + "text_level": 1, + "bbox": [ + 137, + 130, + 831, + 150 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Yaqing Ding $^{1\\dagger}$ , Chiang-Heng Chien $^{2\\dagger}$ , Viktor Larsson $^{1}$ , Karl Åström $^{1}$ , Benjamin Kimia $^{2}$ $^{1}$ Centre for Mathematical Sciences, Lund University \n $^{2}$ School of Engineering, Brown University", + "bbox": [ + 135, + 179, + 834, + 234 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 282, + 313, + 300 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "For a generalized (or non-central) camera model, the minimal problem for two views of six points has efficient solvers. However, minimal problems of three views with four points and three views of six lines have not yet been explored and solved, despite the efforts from the computer vision community. This paper develops the formulations of these two minimal problems and shows how state-of-the-art GPU implementations of Homotopy Continuation solver can be used effectively. The proposed methods are evaluated on both synthetic and real datasets, demonstrating that they are fast, accurate and that they improve on structure from motion estimations, when employed in an hypothesis and test setting.", + "bbox": [ + 73, + 316, + 473, + 513 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 544, + 209, + 559 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In both the central and the non-central camera models, an image point is in correspondence to a ray of a 3D point that projects to that image point. In the central camera model, each such ray goes through a common point, i.e., the camera centre, whereas in the non-central camera model, two such rays do not always intersect. One example of a non-central camera is the catadioptric camera, where one or more lenses and/or mirrors are combined in an optical system, [17]. Another example is a rig of multiple cameras, [20]. A typical use-case is a car or drone equipped with several cameras. Here it is possible to use all of the cameras as one generalized sensor. Generalized cameras offer several advantages over the standard pinhole camera for relative pose estimation. As shown in previous works [20, 25, 10, 15], structure from motion estimation with a generalized camera also gives the scale of the translation as well as the scale of the 3D model. In addition, since the system consists of multiple cameras, it is possible to configure the location of each camera so that a maximal field-of-view can be achieved to avoid blind spots. This, in turn, enables more robust image", + "bbox": [ + 73, + 571, + 470, + 875 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/967268b135f7209fea3d4f2080b544ce85b523595ce129f0a96e4eb22b2c1f03.jpg", + "image_caption": [ + "Figure 1. An example of a multi-camera system with four standard pinhole cameras mounted on a car." + ], + "image_footnote": [], + "bbox": [ + 501, + 280, + 890, + 460 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "feature detection and matching, which is a crucial procedure in relative pose estimation. Fig. 1 shows an example of a multi-camera system consisting of four pinhole cameras mounted on a car for relative pose estimation.", + "bbox": [ + 496, + 521, + 892, + 580 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Unlike the standard pinhole camera, the light rays from a generalized camera do not intersect at a single center of projection. This property makes it non-trivial to estimate the relative pose using a generalized camera. Pless [20] first formulated the light rays in a generalized camera as Plücker vectors and defined the generalized essential matrix. Based on the work of Pless, several solutions to the two-view generalized relative pose estimation have been proposed [26, 10, 25]. Among these solutions, the minimal solver with up to 64 solutions was proposed in [25]. This solver only needs 6 point correspondences which can significantly reduce the number of RANSAC [7] iterations than other solvers. Although the solvers to the two-view generalized relative pose problem are already mature, there are no solutions to the three-view case as the generalized three-view relative pose problem is extremely difficult to be formulated and solved. In general, three-view relative pose estimation needs fewer point correspondence and suffers from fewer degenerate cases than the two-view case. Moreover, three-view relative pose can be estimated only using the line correspondences. Hence, it has a great po", + "bbox": [ + 496, + 583, + 893, + 902 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "$\\dagger$ Equal contribution.", + "bbox": [ + 101, + 887, + 215, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "8156", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 0 + }, + { + "type": "table", + "img_path": "images/8947957ffb4a99c4e958e2cd5043947ad7894cd60490730ecddafadf3d7f9e17.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Point •Line →Quiver •→No. of Solutions
4-point400583
6-line060600
3-quiver0031008
2P3L230920
2P1L1Q2111472
4L1Q0411976
2L2Q0222240
", + "bbox": [ + 101, + 88, + 442, + 241 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Table 1. Possible cases and number of solutions for the generalized three-view relative pose problem. Each row shows the number of necessary features and the number of solutions. We mainly focus on the first two cases in this paper since they are more practical and relevant.", + "bbox": [ + 75, + 250, + 470, + 320 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "tential and can provide new ways to solve the relative pose problem.", + "bbox": [ + 75, + 330, + 468, + 359 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The generalized three-view relative pose problem has 12 degrees of freedom (6 for the two rotations and 6 for the two translations). It is well known that the most commonly used features for relative pose estimation are points, lines and quivers, where a quiver consists of one point with tangent direction (or one point with one line passing through this point). According to the analyses in [5, 6], point, line and quiver in three views can provide 3,2 and 4 constraints, respectively. In Table 1, we show that there are 7 possible minimal cases for generalized three-view relative pose estimation using the combination of the three features. We only assume that there is one line passing through the point, there will be much more cases if there are several lines passing through one point.", + "bbox": [ + 75, + 363, + 468, + 574 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In this paper, to estimate the generalized three-view relative pose, we focus on the first two cases in Table 1. We show detailed discussions on the formulations and the number of solutions for each case. The main contributions of this paper include:", + "bbox": [ + 75, + 577, + 468, + 654 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We solve the generalized three-view relative pose problem using 4 points or 6 lines. Specifically, detailed problem formulation for the two cases are given, which are then converted into solving a squared system of polynomials.", + "- This allows us to develop a solver using HC (homotopy continuation) based on the state-of-the-art GPU-HC solver [2, 3]. This significantly improves the efficiency over the existing modern HC software.", + "- In extensive synthetic and real experiments we show an improvement of accuracy over the state-of-the-art two-view 6-point solver. The proposed 4-point solver is able to deal with semi-pure translation, which is degenerated for the two-view case." + ], + "bbox": [ + 94, + 662, + 468, + 901 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Work", + "text_level": 1, + "bbox": [ + 500, + 89, + 640, + 106 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Three-view Relative Pose. Estimating the calibrated three-view relative pose from standard pinhole cameras has been well studied in the literature. In general, this problem has 11 degrees of freedom (DOF), and can be solved using 4 points [19, 21] or 6 lines [9]. Note that, both 4 points and 6 lines are over-determined for standard pinhole cameras, which makes it difficult to derive stable solvers. The only available solver for the 4-point problem was shown in [11], where the authors added an extra parameter to solve a relaxed version of the problem. To the best of our knowledge, there are no publicly available solvers for the 6-line problem. It was shown in [9] that there might be up to 600 solutions to three-view relative pose with 6 lines using pinhole cameras. While the problem of estimating the three-view relative pose from standard pinhole cameras has received a lot of attention, this does not hold for the generalized three-view relative pose problem. There is only a discussion on the possible number of solutions using 4 points in three generalized views [25].", + "bbox": [ + 496, + 117, + 890, + 404 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Solving Polynomials. Most of the minimal problems in computer vision can be transformed into solving a system of polynomial equations. A straightforward way of solving a polynomial system is to use the Gröbner basis method [4] and generate a specific solver using an automatic generator, e.g., [12, 13, 14]. The Gröbner basis method and related automatic generators have been successfully used in many computer vision problems [14], showing promising results in terms of stability and efficiency. However, it's difficult to find a stable solution for large scale problems using the Gröbner basis technique, since we need to apply Gauss-Jordan elimination and eigenvalue decomposition to large size of matrices. Alternatively, homotopy continuation (HC) [24, 8], one of the promising numerical solver for polynomial equations, is able to handle systems that are out of the reach of the Gröbner basis methods. However, HC algorithms are known to be slow, impractical for many multiview geometry problems when a RANSAC loop is involved, e.g. trifocal relative pose estimation requires over 600 (ms) per correspondence in [6]. This issue has been tackled by GPU-HC [2, 3] where the design of the GPU implementation accelerate the speed in orders of magnitude, giving efficient and accurate estimations for many minimal problems. As there is no paper using GPU-HC to solve minimal problems in practice, this paper stands out as the first approach to leverage it as our solvers.", + "bbox": [ + 496, + 407, + 892, + 800 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "3. Problem Statement", + "text_level": 1, + "bbox": [ + 500, + 814, + 686, + 830 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "As SO(3) is three-dimensional, and we set the first generalized camera to $[1\\mid 0]$ , the parameter space of camera configurations for $n$ -view case has dimension $6n - 6$ . Since one point correspondence in three views gives three constraints,", + "bbox": [ + 496, + 839, + 890, + 902 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "8157", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/8bd0ca09d1ec8b29107a81e2ba5859e8123ff80f64bce0362e07f8a31eb64fe9.jpg", + "image_caption": [ + "Figure 2. The minimal problem of 4 points seen in three generalized cameras. In this example the generalized cameras are visualized as multi-camera systems." + ], + "image_footnote": [], + "bbox": [ + 80, + 73, + 468, + 233 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "and one line correspondence in three views gives two constraints, we can find that 4 points and 6 lines in three views are two minimal cases.", + "bbox": [ + 75, + 301, + 468, + 347 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. The 4-point Case", + "text_level": 1, + "bbox": [ + 76, + 359, + 243, + 376 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Assuming that four points $\\mathbf{X}_1, \\mathbf{X}_2, \\mathbf{X}_3, \\mathbf{X}_4$ in the 3D space are observed by three generalized cameras (Figure 2). Note that, the four points $\\{\\mathbf{X}_1, \\mathbf{X}_2, \\mathbf{X}_3, \\mathbf{X}_4\\}$ can't be viewed from a single pinhole camera, i.e., the points need to be sampled from at least two cameras. Otherwise, the problem will be degenerated into the trifocal relative pose from a standard pinhole camera. The image points of the four 3D points in each view can be written as $\\mathbf{x}_{1i}, \\mathbf{x}_{2i}, \\mathbf{x}_{3i}, \\mathbf{x}_{4i}, i \\in \\{1, 2, 3\\}$ . On the other hand, the rotation matrices and translation vectors that align the image points with the world coordinate are defined as $\\{\\mathbf{A}_{ki}, \\boldsymbol{\\tau}_{ki}\\}$ . We formulate the depths of the image points in each generalized view as $\\lambda_{1i}, \\lambda_{2i}, \\lambda_{3i}, \\lambda_{4i}, i \\in \\{1, 2, 3\\}$ . Due to the rigid motion, the distance between any two points in each view should be the same. Hence, we have", + "bbox": [ + 75, + 383, + 472, + 609 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\left\\| \\lambda_ {1 1} \\mathbf {A} _ {1 1} \\mathbf {x} _ {1 1} + \\boldsymbol {\\tau} _ {1 1} - \\lambda_ {2 1} \\mathbf {A} _ {2 1} \\mathbf {x} _ {2 1} - \\boldsymbol {\\tau} _ {2 1} \\right\\| ^ {2} \\\\ = \\left\\| \\lambda_ {1 2} \\mathbf {A} _ {1 2} \\mathbf {x} _ {1 2} + \\boldsymbol {\\tau} _ {1 2} - \\lambda_ {2 2} \\mathbf {A} _ {2 2} \\mathbf {x} _ {2 2} - \\boldsymbol {\\tau} _ {2 2} \\right\\| ^ {2} \\tag {1} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 76, + 625, + 480, + 696 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\left\\| \\lambda_ {3 1} \\mathbf {A} _ {3 1} \\mathbf {x} _ {3 1} + \\boldsymbol {\\tau} _ {3 1} - \\lambda_ {4 1} \\mathbf {A} _ {4 1} \\mathbf {x} _ {4 1} - \\boldsymbol {\\tau} _ {4 1} \\right\\| ^ {2} \\\\ = \\left\\| \\lambda_ {4 3} \\mathbf {A} _ {4 3} \\mathbf {x} _ {4 3} + \\boldsymbol {\\tau} _ {4 3} - \\lambda_ {4 4} \\mathbf {A} _ {4 4} \\mathbf {x} _ {4 4} - \\boldsymbol {\\tau} _ {4 4} \\right\\| ^ {2} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 76, + 700, + 480, + 739 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this case, we obtain 12 polynomials in 12 unknowns $\\{\\lambda_{1i},\\lambda_{2i},\\lambda_{3i},\\lambda_{4i}\\}$ . Based on [1], we find that there are up to 583 solutions. Once the depth parameters are computed, we let", + "bbox": [ + 76, + 751, + 468, + 810 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {X} _ {k i} = \\lambda_ {k i} \\mathbf {A} _ {k i} \\mathbf {x} _ {k i} + \\boldsymbol {\\tau} _ {k}, \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 189, + 815, + 468, + 830 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $k \\in \\{1, 2, 3, 4\\}$ and $i \\in \\{1, 2, 3\\}$ . We have the following constraints", + "bbox": [ + 76, + 839, + 468, + 869 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {X} _ {k 2} = \\mathbf {R} _ {2} \\mathbf {X} _ {k 1} + \\mathbf {t} _ {2}. \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 199, + 885, + 468, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "By eliminating the translation parameters, we have", + "bbox": [ + 500, + 90, + 836, + 106 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {X} _ {k 2} - \\mathbf {X} _ {1 2} = \\mathbf {R} _ {2} \\left(\\mathbf {X} _ {k 1} - \\mathbf {X} _ {1 1}\\right), k \\in \\{2, 3, 4 \\}. \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 537, + 114, + 890, + 132 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Hence, the rotation matrix $\\mathbf{R}_2$ can be found by", + "bbox": [ + 500, + 141, + 810, + 157 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {R} _ {2} = \\mathbf {B} _ {2} \\mathbf {B} _ {1} ^ {- 1},\n$$\n", + "text_format": "latex", + "bbox": [ + 542, + 164, + 648, + 181 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {B} _ {2} = \\left[ \\mathbf {X} _ {2 2} - \\mathbf {X} _ {1 2}, \\mathbf {X} _ {3 2} - \\mathbf {X} _ {1 2}, \\mathbf {X} _ {4 2} - \\mathbf {X} _ {1 2} \\right], \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 542, + 184, + 890, + 200 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {B} _ {1} = \\left[ \\mathbf {X} _ {2 1} - \\mathbf {X} _ {1 1}, \\mathbf {X} _ {3 1} - \\mathbf {X} _ {1 1}, \\mathbf {X} _ {4 1} - \\mathbf {X} _ {1 1} \\right].\n$$\n", + "text_format": "latex", + "bbox": [ + 542, + 203, + 846, + 220 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Then the translation can be computed using (3). Similarly, we can obtain $\\mathbf{R}_3$ , $\\mathbf{t}_3$ .", + "bbox": [ + 500, + 229, + 890, + 258 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. The 6-line Case", + "text_level": 1, + "bbox": [ + 500, + 267, + 655, + 281 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Assuming that six lines $\\mathbf{L}_1, \\mathbf{L}_2, \\dots, \\mathbf{L}_6$ in the 3D space are observed by three generalized cameras. The projections of the lines in each view can be written as $l_{1i}, l_{2i}, \\dots, l_{6i}, i \\in \\{1, 2, 3\\}$ . The line and the camera center define a plane which passes through the origin of the local camera coordinate. In this case, the plane in each camera coordinate can be formulated as", + "bbox": [ + 498, + 290, + 890, + 393 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {\\pi} _ {k i} = \\left[ \\boldsymbol {l} _ {k i}; 0 \\right]. \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 645, + 396, + 890, + 412 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In addition, we let the $4 \\times 4$ transformation matrices that align the planes with the world coordinate as", + "bbox": [ + 498, + 417, + 890, + 446 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {C} _ {k i} = \\left[ \\begin{array}{c c} \\mathbf {A} _ {k i} & \\boldsymbol {\\tau} _ {k i} \\\\ \\mathbf {0} & 1 \\end{array} \\right]. \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 607, + 455, + 890, + 489 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The planes in three views which are defined by one 3D line should intersect at this line, in this case, we can obtain the following constraints", + "bbox": [ + 498, + 496, + 890, + 542 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\operatorname {r a n k} \\left[ \\mathbf {P} _ {1} ^ {\\top} \\mathbf {C} _ {k} ^ {\\top} \\boldsymbol {\\pi} _ {k 1} \\mid \\mathbf {P} _ {2} ^ {\\top} \\mathbf {C} _ {k} ^ {\\top} \\boldsymbol {\\pi} _ {k 2} \\mid \\mathbf {P} _ {3} ^ {\\top} \\mathbf {C} _ {k} ^ {\\top} \\boldsymbol {\\pi} _ {k 3} \\right] \\leq 2, \\tag {8} \\\\ k \\in \\{1, 2, 3, 4, 5, 6 \\}, \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 519, + 549, + 890, + 585 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where matrix $\\mathbf{P}_i$ is defined as", + "bbox": [ + 500, + 595, + 699, + 609 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {P} _ {i} = \\left[ \\begin{array}{c c} \\mathbf {R} _ {i} & \\boldsymbol {t} _ {i} \\\\ \\mathbf {0} & 1 \\end{array} \\right], i \\in \\{1, 2, 3 \\}. \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 575, + 618, + 890, + 651 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Based on (9), we can obtain $6 * \\mathrm{C}_3^4 = 24$ polynomials in the rotation and translation parameters. If we consider the constraints that only contain the rotation components, we have 6 constraints in the rotation parameters", + "bbox": [ + 498, + 660, + 890, + 720 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\det \\left[ \\mathbf {A} _ {k 1} ^ {\\top} l _ {k 1} \\mid \\mathbf {R} _ {2} ^ {\\top} \\mathbf {A} _ {k 2} ^ {\\top} l _ {k 2} \\mid \\mathbf {R} _ {3} ^ {\\top} \\mathbf {A} _ {k 3} ^ {\\top} l _ {k 3} \\right] = 0, \\tag {10} \\\\ k \\in \\{1, 2, 3, 4, 5, 6 \\}. \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 534, + 728, + 890, + 766 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In order to find the motion parameters, we introduce two formulations for the rotation matrix.", + "bbox": [ + 498, + 775, + 890, + 803 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Cayley parameterization. The major advantage lies in this formulation is that there remain only three variables for each rotation matrix:", + "bbox": [ + 498, + 806, + 890, + 851 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {R} _ {2} = \\frac {1}{\\kappa_ {2}} \\left[ \\begin{array}{c c c} 1 + q _ {1} ^ {2} - q _ {2} ^ {2} - q _ {3} ^ {2} & 2 (q _ {1} q _ {2} - q _ {3}) & 2 (q _ {1} q _ {3} + q _ {2}) \\\\ 2 (q _ {1} q _ {2} + q _ {3}) & 1 - q _ {1} ^ {2} + q _ {2} ^ {2} - q _ {3} ^ {2} & 2 (q _ {2} q _ {3} - q _ {1}) \\\\ 2 (q _ {1} q _ {3} - q _ {2}) & 2 (q _ {2} q _ {3} + q _ {1}) & 1 - q _ {1} ^ {2} - q _ {2} ^ {2} + q _ {3} ^ {2} \\end{array} \\right]\n$$\n", + "text_format": "latex", + "bbox": [ + 500, + 858, + 883, + 905 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "8158", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {R} _ {3} = \\frac {1}{\\kappa_ {3}} \\left[ \\begin{array}{c c c} 1 + q _ {4} ^ {2} - q _ {5} ^ {2} - q _ {6} ^ {2} & 2 (q _ {4} q _ {5} - q _ {6}) & 2 (q _ {4} q _ {6} + q _ {5}) \\\\ 2 (q _ {4} q _ {5} + q _ {6}) & 1 - q _ {4} ^ {2} + q _ {5} ^ {2} - q _ {6} ^ {2} & 2 (q _ {5} q _ {6} - q _ {4}) \\\\ 2 (q _ {4} q _ {6} - q _ {5}) & 2 (q _ {5} q _ {6} + q _ {4}) & 1 - q _ {4} ^ {2} - q _ {5} ^ {2} + q _ {6} ^ {2} \\end{array} \\right],\n$$\n", + "text_format": "latex", + "bbox": [ + 76, + 87, + 464, + 137 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\kappa_{2} = 1 + q_{1}^{2} + q_{2}^{2} + q_{3}^{2}$ , $\\kappa_{3} = 1 + q_{4}^{2} + q_{5}^{2} + q_{6}^{2}$ , note that this formulation is unstable in case of Cayley degenerate rotations ( $\\kappa_{2}, \\kappa_{3} = 0$ ). However, the probability for the degenerate case is quite low in practice, and this formulation has been successfully used in many computer vision problems [13]. Since the constraints (10) are homogenous in the rotation matrices, the scale factors $\\kappa_{2}, \\kappa_{3}$ can be omitted. In this case, we can obtain 6 quartic polynomials in 6 unknowns $\\{q_{1}, q_{2}, \\dots, q_{6}\\}$ . The monodromy solver in [1] shows that there are up to 600 solutions. Once the rotation parameters are computed, we need to substitute them into (8) and obtain six linear equations in the translation parameters. The translation $\\mathbf{t}_{2}$ , $\\mathbf{t}_{3}$ can be uniquely obtained.", + "bbox": [ + 75, + 145, + 468, + 343 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Homogeneous rotation matrix. On the other hand, since constraints (8) are invariant to the scale of the rotation matrices, we can use 8 parameters to formulate the rotation up to a scale factor (assuming the first element to be 1)", + "bbox": [ + 75, + 345, + 468, + 406 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {R} _ {2} = \\left[ \\begin{array}{c c c} 1 & r _ {2} & r _ {3} \\\\ r _ {4} & r _ {5} & r _ {6} \\\\ r _ {7} & r _ {8} & r _ {9} \\end{array} \\right], \\mathbf {R} _ {3} = \\left[ \\begin{array}{c c c} 1 & r _ {1 1} & r _ {1 2} \\\\ r _ {1 3} & r _ {1 4} & r _ {1 5} \\\\ r _ {1 6} & r _ {1 7} & r _ {1 8} \\end{array} \\right].\n$$\n", + "text_format": "latex", + "bbox": [ + 91, + 415, + 419, + 465 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The elements $\\{r_2, r_2, \\ldots, r_9\\}$ should satisfy the following constraints", + "bbox": [ + 75, + 474, + 468, + 503 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} r _ {2} r _ {8} + r _ {3} r _ {9} + r _ {7} = 0, r _ {2} r _ {5} + r _ {3} r _ {6} + r _ {4} = 0, \\\\ r _ {4} r _ {6} + r _ {7} r _ {9} + r _ {3} = 0, r _ {4} r _ {5} + r _ {7} r _ {8} + r _ {2} = 0, \\\\ r _ {5} ^ {2} + r _ {6} ^ {2} - r _ {7} ^ {2} - 1 = 0. \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 104, + 513, + 413, + 569 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "In this case, we can obtain 16 quadratic polynomials in 16 unknowns $\\{r_2,r_3,\\dots,r_{18}\\}$ . Similar to the Cayley parameterization, this formulation is unstable in case of degenerate rotations $(r_1,r_{10} = 0)$ . Although such degenerate cases can be avoided by using unit quaternion formulation, it will result in more parameters than the Cayley parameterization and the system of polynomials has 2-fold symmetry. In order to derive more efficient solvers, we only discuss Cayley parameterization and homogeneous rotation matrix formulation in this paper.", + "bbox": [ + 75, + 578, + 468, + 731 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Geometric Interpretation of (10). The line projection with the camera center define a plane, and this plane gives a line at infinity. Since the three lines in three views should correspond to the same 3D line, the three lines at infinity should intersect at the same point. In this case, we can obtain constraint (10).", + "bbox": [ + 75, + 732, + 468, + 823 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Degenerate Case", + "text_level": 1, + "bbox": [ + 76, + 832, + 241, + 848 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "A detailed analysis of the degeneracies for generalized two-view relative pose estimation has been shown in [10, 15]. The degenerated case is slightly different in", + "bbox": [ + 75, + 854, + 468, + 901 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "generalized three-view relative pose problem. In our case, we found that if the multi-camera system undergoes pure translation $(\\mathbf{R}_2 = \\mathbf{R}_3 = \\mathbf{I})$ with only intra-camera correspondences, our solvers can not recover the scale of the translation. However, if we only have $\\mathbf{R}_2 = \\mathbf{I}$ or $\\mathbf{R}_3 = \\mathbf{I}$ , our solvers can still recover the translation with scale factor.", + "bbox": [ + 496, + 90, + 890, + 181 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "4. Polynomial System Solver", + "text_level": 1, + "bbox": [ + 498, + 193, + 741, + 210 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/143b08a095f7f6656cad26d73d7121f34744207038f5ac6349058b01efbcd214.jpg", + "image_caption": [ + "Figure 3. A track (curve) of a Homotopy Continuation algorithm showing $H(X, t)$ in black, along with one prediction (red) and one correction (blue)." + ], + "image_footnote": [], + "bbox": [ + 519, + 229, + 870, + 338 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Homotopy Continuation: The idea of Homotopy Continuation (HC) [18, 24] is to evolve the solutions of one polynomial system $G$ , the \"start system\", to discover the solutions of another system $F$ , the \"target system\". Let $X = (x_{1}, x_{2}, \\ldots, x_{M})$ represent $M$ unknowns. Let $F(X)$ be a system of $N$ polynomial equations $F = (f_{1}, f_{2}, \\ldots, f_{N})$ . Let $G(x)$ , $G = (g_{1}, g_{2}, \\ldots, g_{N})$ be the \"start system\" whose solutions are all known. The idea of HC is to construct a series of intermediate polynomial systems $H(X, t)$ , $H = (H_{1}, H_{2}, \\ldots, H_{N})$ ; where $H(X, 0) = G(X)$ and $H(X, 1) = F(X)$ , e.g., via linear interpolation:", + "bbox": [ + 498, + 397, + 890, + 565 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nH (x, t) = (1 - t) G (x) + t F (x), \\quad t \\in [ 0, 1 ]. \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 521, + 571, + 890, + 589 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The basic idea is to find the solution of $H(X, t + \\Delta t)$ from the solution of $H(X, t)$ . Figure 3 illustrates the idea for one solution and one unknown. The black curve is the locus of the solution $X(t)$ of $H(X, t)$ , the homotopy curve, where $X_0$ is the known solution of $G(X)$ and $X_1$ is the desired solution of $F(X)$ . We track solution $X_1$ from $X_0$ in a number of small steps, each consisting of a prediction and a correction step. Prediction uses a first-order Taylor expansion to estimate $X$ at $t + \\Delta t$ in the form of", + "bbox": [ + 496, + 595, + 890, + 733 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nX ^ {*} (t + \\Delta t) = X (t) + \\frac {d X}{d t} \\Delta t, \\tag {12}\n$$\n", + "text_format": "latex", + "bbox": [ + 591, + 739, + 890, + 758 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $X^{*}$ is the first order estimation of $X(t + \\Delta t)$ . We obtain $\\frac{dX}{dt}$ by differentiating $H(X(t),t)$ , i.e.,", + "bbox": [ + 496, + 765, + 890, + 797 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\frac {\\partial H}{\\partial X} \\frac {d X}{d t} + \\frac {\\partial H}{\\partial t} = 0 \\longrightarrow \\frac {d X}{d t} = - \\left(\\frac {\\partial H}{\\partial X}\\right) ^ {- 1} \\frac {\\partial H}{\\partial t}, \\tag {13}\n$$\n", + "text_format": "latex", + "bbox": [ + 517, + 801, + 890, + 835 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $J = \\frac{\\partial H}{\\partial x}$ is the $M \\times N$ Jacobian of $H$ wrt $X$ , giving", + "bbox": [ + 500, + 840, + 890, + 859 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nX ^ {*} (t + \\Delta t) = X (t) - \\left(\\frac {\\partial H}{\\partial X}\\right) ^ {- 1} \\frac {\\partial H}{\\partial t} \\Delta t. \\tag {14}\n$$\n", + "text_format": "latex", + "bbox": [ + 565, + 878, + 890, + 898 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "8159", + "bbox": [ + 480, + 944, + 514, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The first-order estimation of $X^{*}$ from $X(t)$ is known as the prediction step (Figure 3) which can be further improved using a higher-order method such as a fourth order Runge-Kutta. Followed by a correction step which helps improve the prediction, Newton's update $X^{*}(t + \\Delta t)$ to $\\hat{X}(t + \\Delta t)$ is used, i.e.,", + "bbox": [ + 75, + 90, + 472, + 181 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nH \\left(X ^ {*}, t + \\Delta t\\right) + \\frac {\\partial H}{\\partial X} \\left(X ^ {*}, t + \\Delta t\\right) \\left(\\hat {X} - X ^ {*}\\right) = 0, \\tag {15}\n$$\n", + "text_format": "latex", + "bbox": [ + 88, + 186, + 468, + 208 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "giving the estimate $\\hat{X}$ in the form of", + "bbox": [ + 76, + 215, + 321, + 231 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\hat {X} = X ^ {*} - \\left(\\frac {\\partial H}{\\partial X}\\right) ^ {- 1} \\left(X ^ {*}, t + \\Delta t\\right) H \\left(X ^ {*}, t + \\Delta t\\right). \\tag {16}\n$$\n", + "text_format": "latex", + "bbox": [ + 94, + 236, + 468, + 256 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The pairs of prediction and correction numerically evolve $X_0$ as the solution of $G(X)$ to $X_1$ as the solution of $F(X)$ . HC algorithms find all the solutions (up to some approximation) with probability one given a good start system which can be provided easily by a monodromy solver [1]. In many computer vision applications, a good start system usually needs to be created once as multiple target systems correspond to different target parameters can be solved from the same start system under a RANSAC loop.", + "bbox": [ + 75, + 262, + 468, + 398 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "GPU-HC: The iterative nature of HC prevents it from being practically used. The GPU implementation in [2, 3] parallelizes (i) HC paths and (ii) the evaluations of $\\frac{\\partial H}{\\partial X}$ , $\\frac{\\partial H}{\\partial t}$ , and $H$ , Equations (13) and (16) to enable HC efficiently solves problems whose complexity has far evaded a practical solution. We thus use GPU-HC as our minimal problem solver, giving promising results in our experiments.", + "bbox": [ + 75, + 400, + 468, + 507 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "GPU-HC Solution Refinement: Since GPU computation is memory-bound, extending numerical precision in GPU computation would significantly drag down efficiency. To obtain high numerical accuracy while avoiding slowdown, Levenberg-Marquardt algorithm using double precision is used, followed by GPU-HC using single precision for solution refinement. This refinement step can be done in CPU side efficiently as only partial GPU-HC solutions are necessary to be refined, i.e., real solutions in the 6-line problem or real and positive solutions in the 4-point problem.", + "bbox": [ + 75, + 508, + 468, + 660 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 76, + 671, + 209, + 688 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To demonstrate that the proposed solvers work well in practice, we conduct extensive experiments on both synthetic and real-world data with multi-camera system configuration. Experiments are run on a 16-Core 3.6GHz Intel i7-11700K CPU and a NVIDIA Titan V GPU.", + "bbox": [ + 75, + 696, + 468, + 771 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "For both synthetic and real experiments, the solver's performance is evaluated by the following criteria:", + "bbox": [ + 76, + 772, + 468, + 803 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\xi_ {\\mathbf {R} [ \\mathrm {d e g} ]} = 2 \\arcsin \\left(\\frac {\\| \\mathbf {R} _ {g t} - \\mathbf {R} _ {e} \\|}{2 \\sqrt {2}}\\right), \\\\ \\xi_ {\\mathbf {t} [ \\mathrm {d e g} ]} = 2 \\arcsin \\left(\\frac {1}{2} \\left\\| \\frac {\\mathbf {t} _ {e}}{\\| \\mathbf {t} _ {e} \\|} - \\frac {\\mathbf {t} _ {g}}{\\| \\mathbf {t} _ {g} \\|} \\right\\|\\right), \\\\ \\xi_ {\\text {S c a l e}} = \\operatorname {a b s} \\left(\\| \\mathbf {t} _ {e} \\| / \\| \\mathbf {t} _ {g t} \\| - 1\\right), \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 130, + 808, + 411, + 897 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $\\xi_{\\mathbf{R}}$ , $\\xi_{\\mathbf{t}}$ , and $\\xi_{\\mathrm{Scale}}$ are the angle difference in rotation, direction difference in translation and relative scale error, respectively. $\\mathbf{R}_{gt}, \\mathbf{t}_{gt}$ are the ground truth rotation and translation, and $\\mathbf{R}_e, \\mathbf{t}_e$ are the estimated rotation and translation, respectively. All the norms are Frobenius norm. Note that, computing the rotation angle error and the translation direction error based on the $\\arccos\\left((\\operatorname{trace}(\\mathbf{R}_{\\mathrm{gt}}^\\top \\mathbf{R}_{\\mathrm{e}}) - 1)/2\\right)$ is simpler. However, it's not the best choice. For example, if the relative angle between the rotation matrices is small, $\\left((\\operatorname{trace}(\\mathbf{R}_{\\mathrm{gt}}^\\top \\mathbf{R}_{\\mathrm{e}}) - 1)/2\\right)$ is close to unity in that case and the $\\arccos$ is very sensitive to errors. Hence, it's better to compute angular errors using the $\\arcsin$ formulation. Detailed comparisons between $\\arcsin$ and $\\arccos$ are shown in the supplementary material.", + "bbox": [ + 496, + 90, + 890, + 318 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.1. Numerical Accuracy of the Solvers", + "text_level": 1, + "bbox": [ + 498, + 332, + 803, + 348 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Although it has been reported in [2, 3] that GPU-HC provides promising and acceptable numerical accuracy in solving various minimal problems in computer vision, for the proposed problems to be usable the evaluation on polynomial residual is still necessary. Figure 4 top row shows the accuracy of (a) all GPU-HC converged solutions and (b) the converged solutions correspond to the ground truths, solving 6-line problem and 4-point problem using our synthetic dataset generating 10,000 real parameters for each problem. Both single precision (SP) and double precision (DP) are demonstrated, showing that the solver is able to provide less than $10^{-5}$ accurate results for the majority of the GPU-HC solutions. Nevertheless, if a refinement step is involved, significant shifts in the distributions of residuals can be observed, Figure 4 bottom row, where single precision solu", + "bbox": [ + 496, + 356, + 890, + 584 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/d6b82679418a569165cafc6b33b73f03df1ff883338bdc50917e98762671e210.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 511, + 604, + 687, + 712 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/5d80cf1b275de1ada4719eb80a590656fda8398cdc8c176fe057c84755cf6ddd.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 697, + 607, + 875, + 712 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/595d8b5806d93541377dc477cf22a70792c2974174943537403f9e5954bfe3aa.jpg", + "image_caption": [ + "(a)" + ], + "image_footnote": [], + "bbox": [ + 509, + 718, + 687, + 825 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/c2c03cecc966503d9fb72029efa09bd2c851ebeed80e3d28ee6c48e0f6b43b76.jpg", + "image_caption": [ + "(b)", + "Figure 4. Numerical accuracy of GPU-HC from (a) all converged paths and (b) converged paths correspond to the true solution of the 4-points and 6-lines problems. Top Row: Original. Bottom Row: Refinement." + ], + "image_footnote": [], + "bbox": [ + 697, + 718, + 875, + 825 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "8160", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "tions are nearly as accurate as the double precision.", + "bbox": [ + 76, + 90, + 416, + 106 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.2. Synthetic Evaluation", + "text_level": 1, + "bbox": [ + 76, + 116, + 274, + 132 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/c60b7a8d33ac9e0e28ad0006c3807866adf14ca23c5531b6d305796371542695.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 81, + 140, + 259, + 242 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/50e8d6d67d33d7178aebfeaa045c5facaf20f07c9d6711598e78e24f12ab4386.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 272, + 140, + 450, + 242 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/ad645e44c35c5f86e544be9d1e449e1ca98f50d5a4ef8329eaa97419eb202fd0.jpg", + "image_caption": [ + "Figure 5. Relative errors with noise-free data under random points and movement. Top Row: The 4-point solver. Bottom Row: The 6-line solver." + ], + "image_footnote": [], + "bbox": [ + 80, + 250, + 258, + 353 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/a660c9e32cc5595fdb69d8c38ac399183993ecd9ae872ca1a1497cc9fc6b7cc0.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 272, + 246, + 450, + 353 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this section, we evaluate the numerical stability and the noise resilience of the proposed solvers. We simulated a multi-camera system with six cameras, and the focal length of each pinhole camera is set to $1000\\mathrm{px}$ . To generate the scene we uniformly sample 3D points from the box $[-2,2]\\times [-2,2]\\times [3,6]$ in each camera's local coordinate system. Then based on two points we can generate lines in each camera. Finally these points and lines are transformed with a random but feasible rotation and translation.", + "bbox": [ + 75, + 411, + 467, + 546 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Stability. We randomly generated 1000 noise-free instances with different transformations. Figure 5 top row shows the distribution of the $\\log_{10}$ relative errors of the 4-point solver, and Figure 5 bottom row shows the distribution of the $\\log_{10}$ relative errors of the 6-line solver, respectively. We can see that both solvers are quite stable.", + "bbox": [ + 75, + 549, + 467, + 641 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Noise resilience. In this experiment, we focused on four practical motions: general motion, forward motion (along the $z$ -axis), sideways motion (along the $x$ -axis), and semipure translation $(\\mathbf{R}_2 = \\mathbf{I})$ . Fig. 6 shows the performance of the proposed 4-point solver and 6-line solver under increasing image noise with different standard deviation. We can see that the 4-point solver has almost similar error distributions for the four motions. The only difference is that the translation direction error is slightly larger under sideways motion and forward motion. Overall, the performance of the 4-point solver is stable under different motions with increasing image noise. By contrast, the 6-line solver is more sensitive to image noise, especially the translation direction error. This is possibly due to the noise that we added to the end points. If the points are close to each other, very small noise in the end points may result in extremely large errors in the line direction. Since the 6-line solver is sensitivity", + "bbox": [ + 75, + 643, + 468, + 900 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "to noise, we will focus on the performance of the 4-point solver in the real experiments.", + "bbox": [ + 498, + 90, + 890, + 121 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Complexity analysis and running times. The success rate of finding the HC solutions correspond to the ground truths and the overall timings of our GPU-HC solver is shown in Table 3. Typically, using double precision would give a slowdown in speed compared to single precision, but there are times where double precision is faster than single precision, e.g., the minimum GPU-HC time of 6-line problem. This is because the required number of HC steps is lesser when double precision is used which converges HC tracks faster. The speedup compared to Julia 8-core CPU HC solver in the table also demonstrate the benefit of using GPU-HC, which gives more than $150 \\times$ speedup and $58 \\times$ speedup for single precision of 6-line and 4-point problems, respectively, enabling real-time computation.", + "bbox": [ + 496, + 125, + 890, + 335 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Success rate and accuracy under a RANSAC scheme. Table 2 shows the RANSAC experiment of the 4-point problem using the synthetic dataset with image size $1000 \\times 1000$ pixels. Among the projections of the 1000 synthetic generated scene points, the inliers are corrupted by uniformly distributed noise within a $7 \\times 7$ window, while the outliers are corrupted by shifting the point by at least half the image size. 80 iterations is used for every case running 1000 times, and a successful RANSAC estimation is decided if $\\xi_{\\mathbf{R}[\\mathrm{deg}]} < 2$ degrees. The table shows only $\\mathbf{R}_2$ , $\\mathbf{t}_2$ , and $\\mathbf{s}_2$ since they share similar accuracy with $\\mathbf{R}_3$ , $\\mathbf{t}_3$ , and $\\mathbf{s}_3$ . The errors are the averaged accuracy of successful cases which show that below $70\\%$ outlier ratio the success rate has more than $80\\%$ , and as long as inlier points are picked, the estimation accuracy is very promising.", + "bbox": [ + 496, + 338, + 890, + 565 + ], + "page_idx": 5 + }, + { + "type": "table", + "img_path": "images/7952f2d8fff315222462565ff9eada0012a2a23e31f7f1ce9f3b01717d5dc98c.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
Outlier RatioSuccess Rate\\( {\\xi }_{\\mathbf{R}\\left\\lbrack \\mathrm{{deg}}\\right\\rbrack } \\)\\( {\\xi }_{\\mathbf{t}\\left\\lbrack \\mathrm{{deg}}\\right\\rbrack } \\)\\( {\\xi }_{\\text{Scale }} \\)
10%100%0.1930.0180.009
20%100%0.1990.1330.076
30%100%0.5740.1880.175
40%96.4%0.9970.1590.122
50%90.7%1.3440.4420.169
60%87.1%1.1280.1340.137
70%81.4%0.8950.1430.060
80%66.3%1.4950.3280.329
90%42.7%1.7490.1340.139
", + "bbox": [ + 504, + 578, + 890, + 731 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 2. Performance of the 4-point problem under a RANSAC scheme given different outlier ratios using the synthetic dataset.", + "bbox": [ + 498, + 739, + 890, + 768 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.3. Real-world Experiments", + "text_level": 1, + "bbox": [ + 500, + 780, + 723, + 796 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In order to test the proposed technique on real-world data, we chose the LaMAR [22] dataset, which contains both indoor and outdoor images with illumination and semantic changes as well as dynamic objects. We used the image sequences captured by a multi-camera rig (HoloLens 2).", + "bbox": [ + 496, + 800, + 890, + 876 + ], + "page_idx": 5 + }, + { + "type": "page_footnote", + "text": "1https://lamar.ethz.ch/", + "bbox": [ + 517, + 886, + 699, + 898 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "8161", + "bbox": [ + 482, + 944, + 513, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/e80d3067e31837f045a56494858c800afa262c28eccbc111417337c5a3c69804.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 84, + 87, + 279, + 205 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/97dbae3c86f767a35572132213b9dbf519877e07d55486f044a3d6bcb87fb7d6.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 285, + 87, + 480, + 205 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/2566f398addc4ce68565ba3c2d847f95e21f919b2920e31d245ff8266da530d6.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 488, + 87, + 684, + 205 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/6c73f3f6280722a7a4593402a56ead53ecbaa43cfb4ab86657baef2269ccc816.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 691, + 88, + 885, + 205 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/8bee8e685e0145f1b460b685051966f1e3bfc45b94c63b9d439db50bbdf4bbae.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 83, + 207, + 279, + 323 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/34f6cd00b14068689e95e19adbccc35d8de864a52879c5a19500331914e7d6d8.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 287, + 207, + 480, + 323 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/2428c96a26cb7bf4e06bd4c3ed03ec7d8e8265e902779042f700f65083bb2c89.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 488, + 207, + 683, + 323 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/cfe207372c97c4ee4afeaec9dfc72e54ddf01335ffe7efea0bb9fc5c4b54cb23.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 691, + 207, + 885, + 323 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/6fb4aeab4b40531941b9da83a9c1448521e4c817e4231e06ac4dd460f5854cd1.jpg", + "image_caption": [ + "Figure 6. Boxplot of the relative errors under increasing image noise with a maximum value of 1 pixel. Top Row: Rotation error in degree. Middle Row: Translation error in degree. Bottom Row: Translation scale error. From left column to right column are general motion, sideways motion, forward motion and semi-pure translation, respectively." + ], + "image_footnote": [], + "bbox": [ + 83, + 324, + 279, + 459 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/62d11d488f366568cbc720979b5bb7503b16c8b4b3e79a5b4e6f77579b1cf4a6.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 287, + 324, + 480, + 459 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/b55620d740c2305d83599c3183a0652cef5ad2db26107539e38de0a66ab2ecce.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 488, + 324, + 683, + 459 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/246dd04e0e2ef3ce6dadd514cb6c6dcac0d59b57fc5bb84128dc2787eaec3662.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 691, + 324, + 885, + 459 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/649786cd5735f617fe9d76161a5b82e20c3b488455b458fe0335379c9d014d7c.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
SolverSuccess Rate (%)# of real sols. (# of positive real sols.)GPU-HC Timings (ms)Mean Julia Timings (ms) (8-core CPU)Julia GPU-HC
minmaxmedianmeanminmaxmedianmean
4-point (DP)99.7834(4)93(12)68(8)68.5(8.1)9.632.816.817.4428.2624.6×
4-point (SP)99.0632(2)89(10)52(5)53.2(5.1)5.315.77.27.358.7×
6-line (DP)98.67521398787.72.972.435.434.1110332.3×
6-line (SP)97.63481208482.45.215.47.17.2153.2×
", + "bbox": [ + 81, + 513, + 888, + 623 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Table 3. Success rate of finding the true solutions and the timings of solving the problems.", + "bbox": [ + 214, + 631, + 746, + 645 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/eed162769ab8ff218dc5e7f9898c721d9e7bcc80d24ce3095803f76adcdfb394.jpg", + "image_caption": [ + "Figure 7. An example of four images from the LaMAR CAB dataset captured by a multi-camera rig with four cameras." + ], + "image_footnote": [], + "bbox": [ + 84, + 657, + 465, + 755 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "It has a specialized large field-of-view (FOV) multi-camera tracking rig with four cameras. In general, this dataset contains three large scale sequences including: (i) HGE, the ground floor of a historic university building consists of numerous large halls and broad esplanades on either side with $18000m^2$ . (ii) CAB, a multi-story office building that features a variety of small and large offices, a kitchen, stor", + "bbox": [ + 75, + 794, + 470, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "age rooms, and two courtyards with $12000m^2$ . (iii) LIN, several blocks of an ancient town, characterized by shops, restaurants, and narrow passageways with $15000m^2$ . To setup the experiments we extracted triplets of multi-camera images from the mapping set, where the ground-truth poses are available. From each trajectory in the mapping set we select consecutive triplets satisfying the following criteria; the distance between consecutive rigs is in $[0.2m, 5m]$ and at least two image pairs have more than 50 matches. This yielded in total 1280 (CAB), 1537 (HGE) and 2213 (LIN) triplets for evaluation. Pairwise 2d-2d matches are established using the SIFT[16] implementation in [23].", + "bbox": [ + 496, + 661, + 890, + 843 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Since there are no related solvers for generalized three-view relative pose problem, we only compare the proposed 4-point solver with the two-view 6-point solver [25].", + "bbox": [ + 496, + 854, + 890, + 902 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "8162", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/b826bab8c9eab6bf88e0ca67da3a95153a3ddaf55496d24d95b9a3c7800eb588.jpg", + "image_caption": [ + "Rotation error CDF" + ], + "image_footnote": [], + "bbox": [ + 94, + 99, + 343, + 229 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/5b99f1455a59e229e7d64b22810db520ae40776ed4abc74c5bcac839b82a24b2.jpg", + "image_caption": [ + "Rotation error CDF" + ], + "image_footnote": [], + "bbox": [ + 364, + 99, + 611, + 229 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/514dba690399d98f4c468d334743c0d93b31db942adfc68768c8d6c03ed0f45e.jpg", + "image_caption": [ + "Rotation error CDF" + ], + "image_footnote": [], + "bbox": [ + 633, + 99, + 880, + 229 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/1d00a02b4777fa18067a25c39ef384a3161dc64669a503a2582b601ccf222f90.jpg", + "image_caption": [ + "Translation error CDF" + ], + "image_footnote": [], + "bbox": [ + 98, + 243, + 339, + 367 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/7b754157eeed04b8947d757534d360e5ba3c6d6833187c10a9e141a0f55b0f9b.jpg", + "image_caption": [ + "Translation error CDF" + ], + "image_footnote": [], + "bbox": [ + 369, + 243, + 611, + 367 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/821ab51c9a16a868cd20d18514fb454d4b5742653fa3384fd41e88829e814fe3.jpg", + "image_caption": [ + "Translation error CDF" + ], + "image_footnote": [], + "bbox": [ + 638, + 243, + 880, + 367 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/f0fddc3935c2d788fde28344571dbcf1310f8ce2e86611356ffdf619b953a29c.jpg", + "image_caption": [ + "Scale error CDF", + "CAB", + "Figure 8. The cumulative distribution functions of the rotation, translation and scale errors. Being accurate is interpreted as a curve close to the top-left corner." + ], + "image_footnote": [], + "bbox": [ + 94, + 382, + 339, + 511 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/c6a28a8b98f151914c8a858c9b5d7d0b3cf1c124ca48f11914c7d8e52d004dd9.jpg", + "image_caption": [ + "Scale error CDF", + "HGE" + ], + "image_footnote": [], + "bbox": [ + 364, + 382, + 611, + 511 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/9ee0ecb8ea935533f270653fb5263c9427a8a7ddb076ee5ccdf88da048741966.jpg", + "image_caption": [ + "Scale error CDF" + ], + "image_footnote": [], + "bbox": [ + 633, + 381, + 880, + 511 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/12e6f4d5b59f4cf5ea2953bb29e2c5ed9bce54d8ce1c6c287a4583b5fa82c276.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
LaMARSolver\\( \\xi_R \\)\\( \\xi_t \\)\\( \\xi_S \\)InlierIter
CAB4-point0.541.650.63329105
6-point0.946.510.73317189
HGE4-point0.583.120.8039299
6-point0.978.250.85387193
LIN4-point0.462.010.72573100
6-point0.784.860.81535199
", + "bbox": [ + 84, + 568, + 460, + 703 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 4. The median errors, the number of inliers and the number of RANSAC iterations on the LaMAR dataset.", + "bbox": [ + 75, + 712, + 468, + 739 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "To make a fair comparison, we use the solvers in a simple RANSAC framework with a maximum number of RANSAC iterations set to 500. The inlier-outlier threshold is set to 2 pixels. In Fig. 8, we show the cumulative distribution functions (CDF) of the rotation (in degrees), translation (in degrees) and scale errors on the three tested datasets. Being accurate is interpreted as a curve close to the top-left corner. The median errors are reported in Table 4. The proposed solver leads to more accurate results, more inliers and fewer iterations than the compared two-view method. Due", + "bbox": [ + 75, + 750, + 470, + 900 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "to the lack of space we only show the results using intra correspondences. Results for inter correspondences and mean errors are shown in the supplementary material.", + "bbox": [ + 496, + 570, + 890, + 616 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Limitations. The main limitation is that the refinement step is currently done in CPU. We will consider to include the refinement in the GPU computation in the future.", + "bbox": [ + 496, + 618, + 890, + 662 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "6. Conclusion", + "text_level": 1, + "bbox": [ + 500, + 665, + 617, + 680 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We discuss minimal cases of generalized three-view relative pose estimation. In particular, we propose GPH-HC based solvers to the 4-point and 6-line cases. Experiments on thousands of image pairs from publicly available datasets show that the proposed three-view 4-point solver is superior to the state-of-the-art two-view 6-point solver. One goal of future research is to use the technique proposed in [11] to improve the efficiency. We believe that the proposed method is promising and will be a good complement to existing methods to improve the accuracy and stability of the structure from motion systems.", + "bbox": [ + 496, + 686, + 890, + 852 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgements. VL, KÅ received funding from ELLIIT. Kimia and Chien gratefully acknowledge the support of NSF award 1910530.", + "bbox": [ + 496, + 854, + 890, + 898 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "8163", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 173, + 104 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Paul Breiding and Sascha Timme. HomotopyContinuation.jl: A Package for Homotopy Continuation in Julia. In International Congress on Mathematical Software, pages 458-465. Springer, 2018.", + "[2] Chiang-Heng Chien, Hongyi Fan, Ahmad Abdelfattah, Elias Tsigaridas, Stanimire Tomov, and Benjamin Kimia. GPU-based homotopy continuation for minimal problems in computer vision. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 15765-15776, 2022.", + "[3] Chiang-Heng Chien, Hongyi Fan, Ahmad Abdelfattah, Elias Tsigaridas, Stanimire Tomov, and Benjamin Kimia. Parallel path tracking for homotopy continuation using GPU. In Proceedings of the International Symposium on Symbolic and Algebraic Computation, 2022.", + "[4] David A. Cox, John Little, and Donal O'shea. Using algebraic geometry. Springer Science & Business Media, 2006.", + "[5] Timothy Duff, Kathlen Kohn, Anton Leykin, and Tomas Pajdla. PLMP - Point-Line Minimal Problems in Complete Multi-View Visibility. In IEEE/CVF International Conference on Computer Vision (ICCV), 2019.", + "[6] Ricardo Fabbri, Timothy Duff, Hongyi Fan, Margaret H. Regan, David da C. de Pinho, Elias Tsigaridas, Charles W. Wampler, Jonathan D. Hauenstein, Peter J. Giblin, Benjamin Kimia, Anton Leykin, and Tomas Pajdla. Trifocal Relative Pose From Lines at Points. Trans. Pattern Analysis and Machine Intelligence (PAMI), 2022.", + "[7] Martin A Fischler and Robert C Bolles. Random sample consensus: a paradigm for model fitting with applications to image analysis and automated cartography. Communications of the ACM, 1981.", + "[8] Jonathan D Hauenstein and Margaret H Regan. Adaptive strategies for solving parameterized systems using homotopy continuation. Applied Mathematics and Computation, 332:19-34, 2018.", + "[9] Robert J. Holt and Arun N. Netravali. Motion and structure from line correspondences: Some further results. International Journal of Imaging Systems and Technology, 1994.", + "[10] Hongdong Li, Richard Hartley, and Jae-hak Kim. A linear approach to motion estimation using generalized camera models. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2008.", + "[11] Petr Hruby, Timothy Duff, Anton Leykin, and Tomas Pajdla. Learning to Solve Hard Minimal Problems. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2022.", + "[12] Zuzana Kukelova, Martin Bujnak, and Tomas Pajdla. Automatic generator of minimal problem solvers. In European Conference on Computer Vision (ECCV), 2008.", + "[13] Viktor Larsson, Kalle Åström, and Magnus Oskarsson. Efficient solvers for minimal problems by syzygy-based reduction. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2017.", + "[14] Viktor Larsson, Magnus Oskarsson, Kalle Åström, Alge Wallis, Zuzana Kukelova, and Tomas Pajdla. Beyond gröbner bases: Basis selection for minimal solvers. In" + ], + "bbox": [ + 78, + 114, + 470, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2018.", + "[15] Gim Hee Lee, Marc Pollefeys, and Friedrich Fraundorfer. Relative Pose Estimation for a Multi-camera System with Known Vertical Direction. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2014.", + "[16] David G Lowe. Distinctive image features from scale-invariant keypoints. International Journal of Computer Vision (IJCV), 2004.", + "[17] Branislav Micusik and Tomas Pajdla. Autocalibration & 3d reconstruction with non-central catadioptric cameras. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2004.", + "[18] Alexander Morgan. Solving polynomial systems using continuation for engineering and scientific problems. SIAM, 2009.", + "[19] David Nister and Frederik Schaffalitzky. Four Points in Two or Three Calibrated Views: Theory and Practice. International Journal of Computer Vision, 2006.", + "[20] Robert Pless. Using many cameras as one. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2003.", + "[21] Long Quan, Bill Triggs, and Bernard Mourrain. Some Results on Minimal Euclidean Reconstruction from Four Points. Journal of Mathematical Imaging and Vision, 2006.", + "[22] Paul-Edouard Sarlin, Mihai Dusmanu, Johannes L. Schonberger, Pablo Speciale, Lukas Gruber, Viktor Larsson, Ondrej Miksik, and Marc Pollefeys. LaMAR: Benchmarking Localization and Mapping for Augmented Reality. In European Conference on Computer Vision (ECCV), 2022.", + "[23] Johannes L Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2016.", + "[24] Andrew J Sommese and Charles W Wampler. The Numerical solution of systems of polynomials arising in engineering and science. World Scientific, 2005.", + "[25] Henrik Stewenius, David Nister, Magnus Oskarsson, and Kalle Åström. Solutions to minimal generalized relative pose problems. In Workshop on omnidirectional vision, 2005.", + "[26] Peter Sturm. Multi-View Geometry for General Camera Models. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2005." + ], + "bbox": [ + 503, + 92, + 890, + 688 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "8164", + "bbox": [ + 482, + 944, + 514, + 955 + ], + "page_idx": 8 + } +] \ No newline at end of file diff --git a/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/21f6bf16-a75f-4e22-8ec8-d9aabd4e98e3_model.json b/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/21f6bf16-a75f-4e22-8ec8-d9aabd4e98e3_model.json new file mode 100644 index 0000000000000000000000000000000000000000..c242287ff3ecbd0e58490debe76db1e06e743fe5 --- /dev/null +++ b/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/21f6bf16-a75f-4e22-8ec8-d9aabd4e98e3_model.json @@ -0,0 +1,2308 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.138, + 0.131, + 0.833, + 0.151 + ], + "angle": 0, + "content": "Minimal Solutions to Generalized Three-View Relative Pose Problem" + }, + { + "type": "text", + "bbox": [ + 0.137, + 0.18, + 0.835, + 0.236 + ], + "angle": 0, + "content": "Yaqing Ding\\(^{1\\dagger}\\), Chiang-Heng Chien\\(^{2\\dagger}\\), Viktor Larsson\\(^{1}\\), Karl Åström\\(^{1}\\), Benjamin Kimia\\(^{2}\\) \n\\(^{1}\\)Centre for Mathematical Sciences, Lund University \n\\(^{2}\\)School of Engineering, Brown University" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.284, + 0.314, + 0.301 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.318, + 0.474, + 0.514 + ], + "angle": 0, + "content": "For a generalized (or non-central) camera model, the minimal problem for two views of six points has efficient solvers. However, minimal problems of three views with four points and three views of six lines have not yet been explored and solved, despite the efforts from the computer vision community. This paper develops the formulations of these two minimal problems and shows how state-of-the-art GPU implementations of Homotopy Continuation solver can be used effectively. The proposed methods are evaluated on both synthetic and real datasets, demonstrating that they are fast, accurate and that they improve on structure from motion estimations, when employed in an hypothesis and test setting." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.545, + 0.21, + 0.56 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.075, + 0.572, + 0.471, + 0.875 + ], + "angle": 0, + "content": "In both the central and the non-central camera models, an image point is in correspondence to a ray of a 3D point that projects to that image point. In the central camera model, each such ray goes through a common point, i.e., the camera centre, whereas in the non-central camera model, two such rays do not always intersect. One example of a non-central camera is the catadioptric camera, where one or more lenses and/or mirrors are combined in an optical system, [17]. Another example is a rig of multiple cameras, [20]. A typical use-case is a car or drone equipped with several cameras. Here it is possible to use all of the cameras as one generalized sensor. Generalized cameras offer several advantages over the standard pinhole camera for relative pose estimation. As shown in previous works [20, 25, 10, 15], structure from motion estimation with a generalized camera also gives the scale of the translation as well as the scale of the 3D model. In addition, since the system consists of multiple cameras, it is possible to configure the location of each camera so that a maximal field-of-view can be achieved to avoid blind spots. This, in turn, enables more robust image" + }, + { + "type": "image", + "bbox": [ + 0.503, + 0.281, + 0.891, + 0.462 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.465, + 0.893, + 0.494 + ], + "angle": 0, + "content": "Figure 1. An example of a multi-camera system with four standard pinhole cameras mounted on a car." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.522, + 0.893, + 0.581 + ], + "angle": 0, + "content": "feature detection and matching, which is a crucial procedure in relative pose estimation. Fig. 1 shows an example of a multi-camera system consisting of four pinhole cameras mounted on a car for relative pose estimation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.584, + 0.895, + 0.903 + ], + "angle": 0, + "content": "Unlike the standard pinhole camera, the light rays from a generalized camera do not intersect at a single center of projection. This property makes it non-trivial to estimate the relative pose using a generalized camera. Pless [20] first formulated the light rays in a generalized camera as Plücker vectors and defined the generalized essential matrix. Based on the work of Pless, several solutions to the two-view generalized relative pose estimation have been proposed [26, 10, 25]. Among these solutions, the minimal solver with up to 64 solutions was proposed in [25]. This solver only needs 6 point correspondences which can significantly reduce the number of RANSAC [7] iterations than other solvers. Although the solvers to the two-view generalized relative pose problem are already mature, there are no solutions to the three-view case as the generalized three-view relative pose problem is extremely difficult to be formulated and solved. In general, three-view relative pose estimation needs fewer point correspondence and suffers from fewer degenerate cases than the two-view case. Moreover, three-view relative pose can be estimated only using the line correspondences. Hence, it has a great po" + }, + { + "type": "page_footnote", + "bbox": [ + 0.102, + 0.888, + 0.216, + 0.9 + ], + "angle": 0, + "content": "\\(\\dagger\\) Equal contribution." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8156" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.102, + 0.089, + 0.444, + 0.242 + ], + "angle": 0, + "content": "
Point •Line →Quiver •→No. of Solutions
4-point400583
6-line060600
3-quiver0031008
2P3L230920
2P1L1Q2111472
4L1Q0411976
2L2Q0222240
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.251, + 0.472, + 0.321 + ], + "angle": 0, + "content": "Table 1. Possible cases and number of solutions for the generalized three-view relative pose problem. Each row shows the number of necessary features and the number of solutions. We mainly focus on the first two cases in this paper since they are more practical and relevant." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.331, + 0.47, + 0.361 + ], + "angle": 0, + "content": "tential and can provide new ways to solve the relative pose problem." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.364, + 0.47, + 0.575 + ], + "angle": 0, + "content": "The generalized three-view relative pose problem has 12 degrees of freedom (6 for the two rotations and 6 for the two translations). It is well known that the most commonly used features for relative pose estimation are points, lines and quivers, where a quiver consists of one point with tangent direction (or one point with one line passing through this point). According to the analyses in [5, 6], point, line and quiver in three views can provide 3,2 and 4 constraints, respectively. In Table 1, we show that there are 7 possible minimal cases for generalized three-view relative pose estimation using the combination of the three features. We only assume that there is one line passing through the point, there will be much more cases if there are several lines passing through one point." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.578, + 0.47, + 0.655 + ], + "angle": 0, + "content": "In this paper, to estimate the generalized three-view relative pose, we focus on the first two cases in Table 1. We show detailed discussions on the formulations and the number of solutions for each case. The main contributions of this paper include:" + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.663, + 0.47, + 0.739 + ], + "angle": 0, + "content": "- We solve the generalized three-view relative pose problem using 4 points or 6 lines. Specifically, detailed problem formulation for the two cases are given, which are then converted into solving a squared system of polynomials." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.752, + 0.47, + 0.813 + ], + "angle": 0, + "content": "- This allows us to develop a solver using HC (homotopy continuation) based on the state-of-the-art GPU-HC solver [2, 3]. This significantly improves the efficiency over the existing modern HC software." + }, + { + "type": "text", + "bbox": [ + 0.096, + 0.826, + 0.47, + 0.902 + ], + "angle": 0, + "content": "- In extensive synthetic and real experiments we show an improvement of accuracy over the state-of-the-art two-view 6-point solver. The proposed 4-point solver is able to deal with semi-pure translation, which is degenerated for the two-view case." + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.663, + 0.47, + 0.902 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.09, + 0.642, + 0.107 + ], + "angle": 0, + "content": "2. Related Work" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.118, + 0.892, + 0.405 + ], + "angle": 0, + "content": "Three-view Relative Pose. Estimating the calibrated three-view relative pose from standard pinhole cameras has been well studied in the literature. In general, this problem has 11 degrees of freedom (DOF), and can be solved using 4 points [19, 21] or 6 lines [9]. Note that, both 4 points and 6 lines are over-determined for standard pinhole cameras, which makes it difficult to derive stable solvers. The only available solver for the 4-point problem was shown in [11], where the authors added an extra parameter to solve a relaxed version of the problem. To the best of our knowledge, there are no publicly available solvers for the 6-line problem. It was shown in [9] that there might be up to 600 solutions to three-view relative pose with 6 lines using pinhole cameras. While the problem of estimating the three-view relative pose from standard pinhole cameras has received a lot of attention, this does not hold for the generalized three-view relative pose problem. There is only a discussion on the possible number of solutions using 4 points in three generalized views [25]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.409, + 0.893, + 0.801 + ], + "angle": 0, + "content": "Solving Polynomials. Most of the minimal problems in computer vision can be transformed into solving a system of polynomial equations. A straightforward way of solving a polynomial system is to use the Gröbner basis method [4] and generate a specific solver using an automatic generator, e.g., [12, 13, 14]. The Gröbner basis method and related automatic generators have been successfully used in many computer vision problems [14], showing promising results in terms of stability and efficiency. However, it's difficult to find a stable solution for large scale problems using the Gröbner basis technique, since we need to apply Gauss-Jordan elimination and eigenvalue decomposition to large size of matrices. Alternatively, homotopy continuation (HC) [24, 8], one of the promising numerical solver for polynomial equations, is able to handle systems that are out of the reach of the Gröbner basis methods. However, HC algorithms are known to be slow, impractical for many multiview geometry problems when a RANSAC loop is involved, e.g. trifocal relative pose estimation requires over 600 (ms) per correspondence in [6]. This issue has been tackled by GPU-HC [2, 3] where the design of the GPU implementation accelerate the speed in orders of magnitude, giving efficient and accurate estimations for many minimal problems. As there is no paper using GPU-HC to solve minimal problems in practice, this paper stands out as the first approach to leverage it as our solvers." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.815, + 0.687, + 0.831 + ], + "angle": 0, + "content": "3. Problem Statement" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.903 + ], + "angle": 0, + "content": "As SO(3) is three-dimensional, and we set the first generalized camera to \\([1\\mid 0]\\), the parameter space of camera configurations for \\(n\\)-view case has dimension \\(6n - 6\\). Since one point correspondence in three views gives three constraints," + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8157" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.081, + 0.074, + 0.47, + 0.234 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.234, + 0.47, + 0.276 + ], + "angle": 0, + "content": "Figure 2. The minimal problem of 4 points seen in three generalized cameras. In this example the generalized cameras are visualized as multi-camera systems." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.303, + 0.47, + 0.348 + ], + "angle": 0, + "content": "and one line correspondence in three views gives two constraints, we can find that 4 points and 6 lines in three views are two minimal cases." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.36, + 0.245, + 0.377 + ], + "angle": 0, + "content": "3.1. The 4-point Case" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.385, + 0.473, + 0.611 + ], + "angle": 0, + "content": "Assuming that four points \\(\\mathbf{X}_1, \\mathbf{X}_2, \\mathbf{X}_3, \\mathbf{X}_4\\) in the 3D space are observed by three generalized cameras (Figure 2). Note that, the four points \\(\\{\\mathbf{X}_1, \\mathbf{X}_2, \\mathbf{X}_3, \\mathbf{X}_4\\}\\) can't be viewed from a single pinhole camera, i.e., the points need to be sampled from at least two cameras. Otherwise, the problem will be degenerated into the trifocal relative pose from a standard pinhole camera. The image points of the four 3D points in each view can be written as \\(\\mathbf{x}_{1i}, \\mathbf{x}_{2i}, \\mathbf{x}_{3i}, \\mathbf{x}_{4i}, i \\in \\{1, 2, 3\\}\\). On the other hand, the rotation matrices and translation vectors that align the image points with the world coordinate are defined as \\(\\{\\mathbf{A}_{ki}, \\boldsymbol{\\tau}_{ki}\\}\\). We formulate the depths of the image points in each generalized view as \\(\\lambda_{1i}, \\lambda_{2i}, \\lambda_{3i}, \\lambda_{4i}, i \\in \\{1, 2, 3\\}\\). Due to the rigid motion, the distance between any two points in each view should be the same. Hence, we have" + }, + { + "type": "equation", + "bbox": [ + 0.078, + 0.625, + 0.482, + 0.697 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\left\\| \\lambda_ {1 1} \\mathbf {A} _ {1 1} \\mathbf {x} _ {1 1} + \\boldsymbol {\\tau} _ {1 1} - \\lambda_ {2 1} \\mathbf {A} _ {2 1} \\mathbf {x} _ {2 1} - \\boldsymbol {\\tau} _ {2 1} \\right\\| ^ {2} \\\\ = \\left\\| \\lambda_ {1 2} \\mathbf {A} _ {1 2} \\mathbf {x} _ {1 2} + \\boldsymbol {\\tau} _ {1 2} - \\lambda_ {2 2} \\mathbf {A} _ {2 2} \\mathbf {x} _ {2 2} - \\boldsymbol {\\tau} _ {2 2} \\right\\| ^ {2} \\tag {1} \\\\ \\end{array}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.078, + 0.701, + 0.482, + 0.74 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\left\\| \\lambda_ {3 1} \\mathbf {A} _ {3 1} \\mathbf {x} _ {3 1} + \\boldsymbol {\\tau} _ {3 1} - \\lambda_ {4 1} \\mathbf {A} _ {4 1} \\mathbf {x} _ {4 1} - \\boldsymbol {\\tau} _ {4 1} \\right\\| ^ {2} \\\\ = \\left\\| \\lambda_ {4 3} \\mathbf {A} _ {4 3} \\mathbf {x} _ {4 3} + \\boldsymbol {\\tau} _ {4 3} - \\lambda_ {4 4} \\mathbf {A} _ {4 4} \\mathbf {x} _ {4 4} - \\boldsymbol {\\tau} _ {4 4} \\right\\| ^ {2} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.752, + 0.47, + 0.811 + ], + "angle": 0, + "content": "In this case, we obtain 12 polynomials in 12 unknowns \\(\\{\\lambda_{1i},\\lambda_{2i},\\lambda_{3i},\\lambda_{4i}\\}\\). Based on [1], we find that there are up to 583 solutions. Once the depth parameters are computed, we let" + }, + { + "type": "equation", + "bbox": [ + 0.19, + 0.816, + 0.469, + 0.831 + ], + "angle": 0, + "content": "\\[\n\\mathbf {X} _ {k i} = \\lambda_ {k i} \\mathbf {A} _ {k i} \\mathbf {x} _ {k i} + \\boldsymbol {\\tau} _ {k}, \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.84, + 0.469, + 0.871 + ], + "angle": 0, + "content": "where \\( k \\in \\{1, 2, 3, 4\\} \\) and \\( i \\in \\{1, 2, 3\\} \\). We have the following constraints" + }, + { + "type": "equation", + "bbox": [ + 0.2, + 0.886, + 0.469, + 0.901 + ], + "angle": 0, + "content": "\\[\n\\mathbf {X} _ {k 2} = \\mathbf {R} _ {2} \\mathbf {X} _ {k 1} + \\mathbf {t} _ {2}. \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.092, + 0.838, + 0.107 + ], + "angle": 0, + "content": "By eliminating the translation parameters, we have" + }, + { + "type": "equation", + "bbox": [ + 0.539, + 0.116, + 0.892, + 0.133 + ], + "angle": 0, + "content": "\\[\n\\mathbf {X} _ {k 2} - \\mathbf {X} _ {1 2} = \\mathbf {R} _ {2} \\left(\\mathbf {X} _ {k 1} - \\mathbf {X} _ {1 1}\\right), k \\in \\{2, 3, 4 \\}. \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.142, + 0.812, + 0.158 + ], + "angle": 0, + "content": "Hence, the rotation matrix \\(\\mathbf{R}_2\\) can be found by" + }, + { + "type": "equation", + "bbox": [ + 0.543, + 0.165, + 0.649, + 0.183 + ], + "angle": 0, + "content": "\\[\n\\mathbf {R} _ {2} = \\mathbf {B} _ {2} \\mathbf {B} _ {1} ^ {- 1},\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.543, + 0.185, + 0.891, + 0.202 + ], + "angle": 0, + "content": "\\[\n\\mathbf {B} _ {2} = \\left[ \\mathbf {X} _ {2 2} - \\mathbf {X} _ {1 2}, \\mathbf {X} _ {3 2} - \\mathbf {X} _ {1 2}, \\mathbf {X} _ {4 2} - \\mathbf {X} _ {1 2} \\right], \\tag {5}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.543, + 0.204, + 0.847, + 0.221 + ], + "angle": 0, + "content": "\\[\n\\mathbf {B} _ {1} = \\left[ \\mathbf {X} _ {2 1} - \\mathbf {X} _ {1 1}, \\mathbf {X} _ {3 1} - \\mathbf {X} _ {1 1}, \\mathbf {X} _ {4 1} - \\mathbf {X} _ {1 1} \\right].\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.23, + 0.891, + 0.26 + ], + "angle": 0, + "content": "Then the translation can be computed using (3). Similarly, we can obtain \\(\\mathbf{R}_3\\), \\(\\mathbf{t}_3\\)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.268, + 0.656, + 0.282 + ], + "angle": 0, + "content": "3.2. The 6-line Case" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.291, + 0.892, + 0.395 + ], + "angle": 0, + "content": "Assuming that six lines \\(\\mathbf{L}_1, \\mathbf{L}_2, \\dots, \\mathbf{L}_6\\) in the 3D space are observed by three generalized cameras. The projections of the lines in each view can be written as \\(l_{1i}, l_{2i}, \\dots, l_{6i}, i \\in \\{1, 2, 3\\}\\). The line and the camera center define a plane which passes through the origin of the local camera coordinate. In this case, the plane in each camera coordinate can be formulated as" + }, + { + "type": "equation", + "bbox": [ + 0.647, + 0.397, + 0.891, + 0.413 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {\\pi} _ {k i} = \\left[ \\boldsymbol {l} _ {k i}; 0 \\right]. \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.418, + 0.892, + 0.448 + ], + "angle": 0, + "content": "In addition, we let the \\(4 \\times 4\\) transformation matrices that align the planes with the world coordinate as" + }, + { + "type": "equation", + "bbox": [ + 0.608, + 0.456, + 0.891, + 0.49 + ], + "angle": 0, + "content": "\\[\n\\mathbf {C} _ {k i} = \\left[ \\begin{array}{c c} \\mathbf {A} _ {k i} & \\boldsymbol {\\tau} _ {k i} \\\\ \\mathbf {0} & 1 \\end{array} \\right]. \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.497, + 0.892, + 0.543 + ], + "angle": 0, + "content": "The planes in three views which are defined by one 3D line should intersect at this line, in this case, we can obtain the following constraints" + }, + { + "type": "equation", + "bbox": [ + 0.521, + 0.55, + 0.891, + 0.587 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\operatorname {r a n k} \\left[ \\mathbf {P} _ {1} ^ {\\top} \\mathbf {C} _ {k} ^ {\\top} \\boldsymbol {\\pi} _ {k 1} \\mid \\mathbf {P} _ {2} ^ {\\top} \\mathbf {C} _ {k} ^ {\\top} \\boldsymbol {\\pi} _ {k 2} \\mid \\mathbf {P} _ {3} ^ {\\top} \\mathbf {C} _ {k} ^ {\\top} \\boldsymbol {\\pi} _ {k 3} \\right] \\leq 2, \\tag {8} \\\\ k \\in \\{1, 2, 3, 4, 5, 6 \\}, \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.597, + 0.7, + 0.611 + ], + "angle": 0, + "content": "where matrix \\(\\mathbf{P}_i\\) is defined as" + }, + { + "type": "equation", + "bbox": [ + 0.576, + 0.619, + 0.891, + 0.652 + ], + "angle": 0, + "content": "\\[\n\\mathbf {P} _ {i} = \\left[ \\begin{array}{c c} \\mathbf {R} _ {i} & \\boldsymbol {t} _ {i} \\\\ \\mathbf {0} & 1 \\end{array} \\right], i \\in \\{1, 2, 3 \\}. \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.661, + 0.892, + 0.722 + ], + "angle": 0, + "content": "Based on (9), we can obtain \\( 6 * \\mathrm{C}_3^4 = 24 \\) polynomials in the rotation and translation parameters. If we consider the constraints that only contain the rotation components, we have 6 constraints in the rotation parameters" + }, + { + "type": "equation", + "bbox": [ + 0.535, + 0.729, + 0.891, + 0.767 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\det \\left[ \\mathbf {A} _ {k 1} ^ {\\top} l _ {k 1} \\mid \\mathbf {R} _ {2} ^ {\\top} \\mathbf {A} _ {k 2} ^ {\\top} l _ {k 2} \\mid \\mathbf {R} _ {3} ^ {\\top} \\mathbf {A} _ {k 3} ^ {\\top} l _ {k 3} \\right] = 0, \\tag {10} \\\\ k \\in \\{1, 2, 3, 4, 5, 6 \\}. \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.776, + 0.891, + 0.804 + ], + "angle": 0, + "content": "In order to find the motion parameters, we introduce two formulations for the rotation matrix." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.808, + 0.892, + 0.852 + ], + "angle": 0, + "content": "Cayley parameterization. The major advantage lies in this formulation is that there remain only three variables for each rotation matrix:" + }, + { + "type": "equation", + "bbox": [ + 0.5, + 0.859, + 0.885, + 0.906 + ], + "angle": 0, + "content": "\\[\n\\mathbf {R} _ {2} = \\frac {1}{\\kappa_ {2}} \\left[ \\begin{array}{c c c} 1 + q _ {1} ^ {2} - q _ {2} ^ {2} - q _ {3} ^ {2} & 2 (q _ {1} q _ {2} - q _ {3}) & 2 (q _ {1} q _ {3} + q _ {2}) \\\\ 2 (q _ {1} q _ {2} + q _ {3}) & 1 - q _ {1} ^ {2} + q _ {2} ^ {2} - q _ {3} ^ {2} & 2 (q _ {2} q _ {3} - q _ {1}) \\\\ 2 (q _ {1} q _ {3} - q _ {2}) & 2 (q _ {2} q _ {3} + q _ {1}) & 1 - q _ {1} ^ {2} - q _ {2} ^ {2} + q _ {3} ^ {2} \\end{array} \\right]\n\\]" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8158" + } + ], + [ + { + "type": "equation", + "bbox": [ + 0.078, + 0.088, + 0.465, + 0.138 + ], + "angle": 0, + "content": "\\[\n\\mathbf {R} _ {3} = \\frac {1}{\\kappa_ {3}} \\left[ \\begin{array}{c c c} 1 + q _ {4} ^ {2} - q _ {5} ^ {2} - q _ {6} ^ {2} & 2 (q _ {4} q _ {5} - q _ {6}) & 2 (q _ {4} q _ {6} + q _ {5}) \\\\ 2 (q _ {4} q _ {5} + q _ {6}) & 1 - q _ {4} ^ {2} + q _ {5} ^ {2} - q _ {6} ^ {2} & 2 (q _ {5} q _ {6} - q _ {4}) \\\\ 2 (q _ {4} q _ {6} - q _ {5}) & 2 (q _ {5} q _ {6} + q _ {4}) & 1 - q _ {4} ^ {2} - q _ {5} ^ {2} + q _ {6} ^ {2} \\end{array} \\right],\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.146, + 0.47, + 0.344 + ], + "angle": 0, + "content": "where \\(\\kappa_{2} = 1 + q_{1}^{2} + q_{2}^{2} + q_{3}^{2}\\), \\(\\kappa_{3} = 1 + q_{4}^{2} + q_{5}^{2} + q_{6}^{2}\\), note that this formulation is unstable in case of Cayley degenerate rotations (\\(\\kappa_{2}, \\kappa_{3} = 0\\)). However, the probability for the degenerate case is quite low in practice, and this formulation has been successfully used in many computer vision problems [13]. Since the constraints (10) are homogenous in the rotation matrices, the scale factors \\(\\kappa_{2}, \\kappa_{3}\\) can be omitted. In this case, we can obtain 6 quartic polynomials in 6 unknowns \\(\\{q_{1}, q_{2}, \\dots, q_{6}\\}\\). The monodromy solver in [1] shows that there are up to 600 solutions. Once the rotation parameters are computed, we need to substitute them into (8) and obtain six linear equations in the translation parameters. The translation \\(\\mathbf{t}_{2}\\), \\(\\mathbf{t}_{3}\\) can be uniquely obtained." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.346, + 0.47, + 0.407 + ], + "angle": 0, + "content": "Homogeneous rotation matrix. On the other hand, since constraints (8) are invariant to the scale of the rotation matrices, we can use 8 parameters to formulate the rotation up to a scale factor (assuming the first element to be 1)" + }, + { + "type": "equation", + "bbox": [ + 0.092, + 0.416, + 0.42, + 0.466 + ], + "angle": 0, + "content": "\\[\n\\mathbf {R} _ {2} = \\left[ \\begin{array}{c c c} 1 & r _ {2} & r _ {3} \\\\ r _ {4} & r _ {5} & r _ {6} \\\\ r _ {7} & r _ {8} & r _ {9} \\end{array} \\right], \\mathbf {R} _ {3} = \\left[ \\begin{array}{c c c} 1 & r _ {1 1} & r _ {1 2} \\\\ r _ {1 3} & r _ {1 4} & r _ {1 5} \\\\ r _ {1 6} & r _ {1 7} & r _ {1 8} \\end{array} \\right].\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.475, + 0.47, + 0.505 + ], + "angle": 0, + "content": "The elements \\(\\{r_2, r_2, \\ldots, r_9\\}\\) should satisfy the following constraints" + }, + { + "type": "equation", + "bbox": [ + 0.105, + 0.514, + 0.414, + 0.57 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} r _ {2} r _ {8} + r _ {3} r _ {9} + r _ {7} = 0, r _ {2} r _ {5} + r _ {3} r _ {6} + r _ {4} = 0, \\\\ r _ {4} r _ {6} + r _ {7} r _ {9} + r _ {3} = 0, r _ {4} r _ {5} + r _ {7} r _ {8} + r _ {2} = 0, \\\\ r _ {5} ^ {2} + r _ {6} ^ {2} - r _ {7} ^ {2} - 1 = 0. \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.579, + 0.47, + 0.732 + ], + "angle": 0, + "content": "In this case, we can obtain 16 quadratic polynomials in 16 unknowns \\(\\{r_2,r_3,\\dots,r_{18}\\}\\). Similar to the Cayley parameterization, this formulation is unstable in case of degenerate rotations \\((r_1,r_{10} = 0)\\). Although such degenerate cases can be avoided by using unit quaternion formulation, it will result in more parameters than the Cayley parameterization and the system of polynomials has 2-fold symmetry. In order to derive more efficient solvers, we only discuss Cayley parameterization and homogeneous rotation matrix formulation in this paper." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.733, + 0.469, + 0.824 + ], + "angle": 0, + "content": "Geometric Interpretation of (10). The line projection with the camera center define a plane, and this plane gives a line at infinity. Since the three lines in three views should correspond to the same 3D line, the three lines at infinity should intersect at the same point. In this case, we can obtain constraint (10)." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.833, + 0.243, + 0.849 + ], + "angle": 0, + "content": "3.3. Degenerate Case" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.856, + 0.47, + 0.902 + ], + "angle": 0, + "content": "A detailed analysis of the degeneracies for generalized two-view relative pose estimation has been shown in [10, 15]. The degenerated case is slightly different in" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.182 + ], + "angle": 0, + "content": "generalized three-view relative pose problem. In our case, we found that if the multi-camera system undergoes pure translation \\((\\mathbf{R}_2 = \\mathbf{R}_3 = \\mathbf{I})\\) with only intra-camera correspondences, our solvers can not recover the scale of the translation. However, if we only have \\(\\mathbf{R}_2 = \\mathbf{I}\\) or \\(\\mathbf{R}_3 = \\mathbf{I}\\), our solvers can still recover the translation with scale factor." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.194, + 0.743, + 0.212 + ], + "angle": 0, + "content": "4. Polynomial System Solver" + }, + { + "type": "image", + "bbox": [ + 0.52, + 0.23, + 0.871, + 0.339 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.341, + 0.892, + 0.383 + ], + "angle": 0, + "content": "Figure 3. A track (curve) of a Homotopy Continuation algorithm showing \\( H(X, t) \\) in black, along with one prediction (red) and one correction (blue)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.398, + 0.892, + 0.566 + ], + "angle": 0, + "content": "Homotopy Continuation: The idea of Homotopy Continuation (HC) [18, 24] is to evolve the solutions of one polynomial system \\( G \\), the \"start system\", to discover the solutions of another system \\( F \\), the \"target system\". Let \\( X = (x_{1}, x_{2}, \\ldots, x_{M}) \\) represent \\( M \\) unknowns. Let \\( F(X) \\) be a system of \\( N \\) polynomial equations \\( F = (f_{1}, f_{2}, \\ldots, f_{N}) \\). Let \\( G(x) \\), \\( G = (g_{1}, g_{2}, \\ldots, g_{N}) \\) be the \"start system\" whose solutions are all known. The idea of HC is to construct a series of intermediate polynomial systems \\( H(X, t) \\), \\( H = (H_{1}, H_{2}, \\ldots, H_{N}) \\); where \\( H(X, 0) = G(X) \\) and \\( H(X, 1) = F(X) \\), e.g., via linear interpolation:" + }, + { + "type": "equation", + "bbox": [ + 0.522, + 0.573, + 0.891, + 0.59 + ], + "angle": 0, + "content": "\\[\nH (x, t) = (1 - t) G (x) + t F (x), \\quad t \\in [ 0, 1 ]. \\tag {11}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.597, + 0.892, + 0.734 + ], + "angle": 0, + "content": "The basic idea is to find the solution of \\( H(X, t + \\Delta t) \\) from the solution of \\( H(X, t) \\). Figure 3 illustrates the idea for one solution and one unknown. The black curve is the locus of the solution \\( X(t) \\) of \\( H(X, t) \\), the homotopy curve, where \\( X_0 \\) is the known solution of \\( G(X) \\) and \\( X_1 \\) is the desired solution of \\( F(X) \\). We track solution \\( X_1 \\) from \\( X_0 \\) in a number of small steps, each consisting of a prediction and a correction step. Prediction uses a first-order Taylor expansion to estimate \\( X \\) at \\( t + \\Delta t \\) in the form of" + }, + { + "type": "equation", + "bbox": [ + 0.593, + 0.74, + 0.891, + 0.759 + ], + "angle": 0, + "content": "\\[\nX ^ {*} (t + \\Delta t) = X (t) + \\frac {d X}{d t} \\Delta t, \\tag {12}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.766, + 0.891, + 0.798 + ], + "angle": 0, + "content": "where \\(X^{*}\\) is the first order estimation of \\(X(t + \\Delta t)\\). We obtain \\(\\frac{dX}{dt}\\) by differentiating \\(H(X(t),t)\\), i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.519, + 0.803, + 0.891, + 0.836 + ], + "angle": 0, + "content": "\\[\n\\frac {\\partial H}{\\partial X} \\frac {d X}{d t} + \\frac {\\partial H}{\\partial t} = 0 \\longrightarrow \\frac {d X}{d t} = - \\left(\\frac {\\partial H}{\\partial X}\\right) ^ {- 1} \\frac {\\partial H}{\\partial t}, \\tag {13}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.841, + 0.892, + 0.86 + ], + "angle": 0, + "content": "where \\( J = \\frac{\\partial H}{\\partial x} \\) is the \\( M \\times N \\) Jacobian of \\( H \\) wrt \\( X \\), giving" + }, + { + "type": "equation", + "bbox": [ + 0.566, + 0.879, + 0.891, + 0.9 + ], + "angle": 0, + "content": "\\[\nX ^ {*} (t + \\Delta t) = X (t) - \\left(\\frac {\\partial H}{\\partial X}\\right) ^ {- 1} \\frac {\\partial H}{\\partial t} \\Delta t. \\tag {14}\n\\]" + }, + { + "type": "page_number", + "bbox": [ + 0.482, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8159" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.091, + 0.473, + 0.182 + ], + "angle": 0, + "content": "The first-order estimation of \\( X^{*} \\) from \\( X(t) \\) is known as the prediction step (Figure 3) which can be further improved using a higher-order method such as a fourth order Runge-Kutta. Followed by a correction step which helps improve the prediction, Newton's update \\( X^{*}(t + \\Delta t) \\) to \\( \\hat{X}(t + \\Delta t) \\) is used, i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.089, + 0.188, + 0.47, + 0.209 + ], + "angle": 0, + "content": "\\[\nH \\left(X ^ {*}, t + \\Delta t\\right) + \\frac {\\partial H}{\\partial X} \\left(X ^ {*}, t + \\Delta t\\right) \\left(\\hat {X} - X ^ {*}\\right) = 0, \\tag {15}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.216, + 0.322, + 0.232 + ], + "angle": 0, + "content": "giving the estimate \\(\\hat{X}\\) in the form of" + }, + { + "type": "equation", + "bbox": [ + 0.095, + 0.237, + 0.469, + 0.257 + ], + "angle": 0, + "content": "\\[\n\\hat {X} = X ^ {*} - \\left(\\frac {\\partial H}{\\partial X}\\right) ^ {- 1} \\left(X ^ {*}, t + \\Delta t\\right) H \\left(X ^ {*}, t + \\Delta t\\right). \\tag {16}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.263, + 0.47, + 0.399 + ], + "angle": 0, + "content": "The pairs of prediction and correction numerically evolve \\( X_0 \\) as the solution of \\( G(X) \\) to \\( X_1 \\) as the solution of \\( F(X) \\). HC algorithms find all the solutions (up to some approximation) with probability one given a good start system which can be provided easily by a monodromy solver [1]. In many computer vision applications, a good start system usually needs to be created once as multiple target systems correspond to different target parameters can be solved from the same start system under a RANSAC loop." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.401, + 0.469, + 0.508 + ], + "angle": 0, + "content": "GPU-HC: The iterative nature of HC prevents it from being practically used. The GPU implementation in [2, 3] parallelizes (i) HC paths and (ii) the evaluations of \\(\\frac{\\partial H}{\\partial X}\\), \\(\\frac{\\partial H}{\\partial t}\\), and \\(H\\), Equations (13) and (16) to enable HC efficiently solves problems whose complexity has far evaded a practical solution. We thus use GPU-HC as our minimal problem solver, giving promising results in our experiments." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.509, + 0.47, + 0.661 + ], + "angle": 0, + "content": "GPU-HC Solution Refinement: Since GPU computation is memory-bound, extending numerical precision in GPU computation would significantly drag down efficiency. To obtain high numerical accuracy while avoiding slowdown, Levenberg-Marquardt algorithm using double precision is used, followed by GPU-HC using single precision for solution refinement. This refinement step can be done in CPU side efficiently as only partial GPU-HC solutions are necessary to be refined, i.e., real solutions in the 6-line problem or real and positive solutions in the 4-point problem." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.672, + 0.21, + 0.689 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.697, + 0.469, + 0.772 + ], + "angle": 0, + "content": "To demonstrate that the proposed solvers work well in practice, we conduct extensive experiments on both synthetic and real-world data with multi-camera system configuration. Experiments are run on a 16-Core 3.6GHz Intel i7-11700K CPU and a NVIDIA Titan V GPU." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.773, + 0.469, + 0.804 + ], + "angle": 0, + "content": "For both synthetic and real experiments, the solver's performance is evaluated by the following criteria:" + }, + { + "type": "equation", + "bbox": [ + 0.131, + 0.809, + 0.413, + 0.898 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\xi_ {\\mathbf {R} [ \\mathrm {d e g} ]} = 2 \\arcsin \\left(\\frac {\\| \\mathbf {R} _ {g t} - \\mathbf {R} _ {e} \\|}{2 \\sqrt {2}}\\right), \\\\ \\xi_ {\\mathbf {t} [ \\mathrm {d e g} ]} = 2 \\arcsin \\left(\\frac {1}{2} \\left\\| \\frac {\\mathbf {t} _ {e}}{\\| \\mathbf {t} _ {e} \\|} - \\frac {\\mathbf {t} _ {g}}{\\| \\mathbf {t} _ {g} \\|} \\right\\|\\right), \\\\ \\xi_ {\\text {S c a l e}} = \\operatorname {a b s} \\left(\\| \\mathbf {t} _ {e} \\| / \\| \\mathbf {t} _ {g t} \\| - 1\\right), \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.319 + ], + "angle": 0, + "content": "where \\(\\xi_{\\mathbf{R}}\\), \\(\\xi_{\\mathbf{t}}\\), and \\(\\xi_{\\mathrm{Scale}}\\) are the angle difference in rotation, direction difference in translation and relative scale error, respectively. \\(\\mathbf{R}_{gt}, \\mathbf{t}_{gt}\\) are the ground truth rotation and translation, and \\(\\mathbf{R}_e, \\mathbf{t}_e\\) are the estimated rotation and translation, respectively. All the norms are Frobenius norm. Note that, computing the rotation angle error and the translation direction error based on the \\(\\arccos\\left((\\operatorname{trace}(\\mathbf{R}_{\\mathrm{gt}}^\\top \\mathbf{R}_{\\mathrm{e}}) - 1)/2\\right)\\) is simpler. However, it's not the best choice. For example, if the relative angle between the rotation matrices is small, \\(\\left((\\operatorname{trace}(\\mathbf{R}_{\\mathrm{gt}}^\\top \\mathbf{R}_{\\mathrm{e}}) - 1)/2\\right)\\) is close to unity in that case and the \\(\\arccos\\) is very sensitive to errors. Hence, it's better to compute angular errors using the \\(\\arcsin\\) formulation. Detailed comparisons between \\(\\arcsin\\) and \\(\\arccos\\) are shown in the supplementary material." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.333, + 0.804, + 0.349 + ], + "angle": 0, + "content": "5.1. Numerical Accuracy of the Solvers" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.357, + 0.892, + 0.585 + ], + "angle": 0, + "content": "Although it has been reported in [2, 3] that GPU-HC provides promising and acceptable numerical accuracy in solving various minimal problems in computer vision, for the proposed problems to be usable the evaluation on polynomial residual is still necessary. Figure 4 top row shows the accuracy of (a) all GPU-HC converged solutions and (b) the converged solutions correspond to the ground truths, solving 6-line problem and 4-point problem using our synthetic dataset generating 10,000 real parameters for each problem. Both single precision (SP) and double precision (DP) are demonstrated, showing that the solver is able to provide less than \\(10^{-5}\\) accurate results for the majority of the GPU-HC solutions. Nevertheless, if a refinement step is involved, significant shifts in the distributions of residuals can be observed, Figure 4 bottom row, where single precision solu" + }, + { + "type": "image", + "bbox": [ + 0.512, + 0.605, + 0.689, + 0.713 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.699, + 0.608, + 0.876, + 0.713 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.511, + 0.719, + 0.688, + 0.826 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.598, + 0.835, + 0.616, + 0.845 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "image", + "bbox": [ + 0.699, + 0.719, + 0.876, + 0.826 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.786, + 0.835, + 0.804, + 0.845 + ], + "angle": 0, + "content": "(b)" + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.845, + 0.892, + 0.9 + ], + "angle": 0, + "content": "Figure 4. Numerical accuracy of GPU-HC from (a) all converged paths and (b) converged paths correspond to the true solution of the 4-points and 6-lines problems. Top Row: Original. Bottom Row: Refinement." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8160" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.078, + 0.092, + 0.417, + 0.107 + ], + "angle": 0, + "content": "tions are nearly as accurate as the double precision." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.117, + 0.275, + 0.133 + ], + "angle": 0, + "content": "5.2. Synthetic Evaluation" + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.141, + 0.26, + 0.243 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.274, + 0.141, + 0.452, + 0.243 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.25, + 0.259, + 0.354 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.274, + 0.247, + 0.451, + 0.354 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.357, + 0.47, + 0.398 + ], + "angle": 0, + "content": "Figure 5. Relative errors with noise-free data under random points and movement. Top Row: The 4-point solver. Bottom Row: The 6-line solver." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.412, + 0.468, + 0.547 + ], + "angle": 0, + "content": "In this section, we evaluate the numerical stability and the noise resilience of the proposed solvers. We simulated a multi-camera system with six cameras, and the focal length of each pinhole camera is set to \\(1000\\mathrm{px}\\). To generate the scene we uniformly sample 3D points from the box \\([-2,2]\\times [-2,2]\\times [3,6]\\) in each camera's local coordinate system. Then based on two points we can generate lines in each camera. Finally these points and lines are transformed with a random but feasible rotation and translation." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.55, + 0.468, + 0.642 + ], + "angle": 0, + "content": "Stability. We randomly generated 1000 noise-free instances with different transformations. Figure 5 top row shows the distribution of the \\(\\log_{10}\\) relative errors of the 4-point solver, and Figure 5 bottom row shows the distribution of the \\(\\log_{10}\\) relative errors of the 6-line solver, respectively. We can see that both solvers are quite stable." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.644, + 0.47, + 0.901 + ], + "angle": 0, + "content": "Noise resilience. In this experiment, we focused on four practical motions: general motion, forward motion (along the \\(z\\)-axis), sideways motion (along the \\(x\\)-axis), and semipure translation \\((\\mathbf{R}_2 = \\mathbf{I})\\). Fig. 6 shows the performance of the proposed 4-point solver and 6-line solver under increasing image noise with different standard deviation. We can see that the 4-point solver has almost similar error distributions for the four motions. The only difference is that the translation direction error is slightly larger under sideways motion and forward motion. Overall, the performance of the 4-point solver is stable under different motions with increasing image noise. By contrast, the 6-line solver is more sensitive to image noise, especially the translation direction error. This is possibly due to the noise that we added to the end points. If the points are close to each other, very small noise in the end points may result in extremely large errors in the line direction. Since the 6-line solver is sensitivity" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.122 + ], + "angle": 0, + "content": "to noise, we will focus on the performance of the 4-point solver in the real experiments." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.125, + 0.892, + 0.336 + ], + "angle": 0, + "content": "Complexity analysis and running times. The success rate of finding the HC solutions correspond to the ground truths and the overall timings of our GPU-HC solver is shown in Table 3. Typically, using double precision would give a slowdown in speed compared to single precision, but there are times where double precision is faster than single precision, e.g., the minimum GPU-HC time of 6-line problem. This is because the required number of HC steps is lesser when double precision is used which converges HC tracks faster. The speedup compared to Julia 8-core CPU HC solver in the table also demonstrate the benefit of using GPU-HC, which gives more than \\(150 \\times\\) speedup and \\(58 \\times\\) speedup for single precision of 6-line and 4-point problems, respectively, enabling real-time computation." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.339, + 0.892, + 0.566 + ], + "angle": 0, + "content": "Success rate and accuracy under a RANSAC scheme. Table 2 shows the RANSAC experiment of the 4-point problem using the synthetic dataset with image size \\(1000 \\times 1000\\) pixels. Among the projections of the 1000 synthetic generated scene points, the inliers are corrupted by uniformly distributed noise within a \\(7 \\times 7\\) window, while the outliers are corrupted by shifting the point by at least half the image size. 80 iterations is used for every case running 1000 times, and a successful RANSAC estimation is decided if \\(\\xi_{\\mathbf{R}[\\mathrm{deg}]} < 2\\) degrees. The table shows only \\(\\mathbf{R}_2\\), \\(\\mathbf{t}_2\\), and \\(\\mathbf{s}_2\\) since they share similar accuracy with \\(\\mathbf{R}_3\\), \\(\\mathbf{t}_3\\), and \\(\\mathbf{s}_3\\). The errors are the averaged accuracy of successful cases which show that below \\(70\\%\\) outlier ratio the success rate has more than \\(80\\%\\), and as long as inlier points are picked, the estimation accuracy is very promising." + }, + { + "type": "table", + "bbox": [ + 0.506, + 0.579, + 0.892, + 0.732 + ], + "angle": 0, + "content": "
Outlier RatioSuccess Rate\\( {\\xi }_{\\mathbf{R}\\left\\lbrack \\mathrm{{deg}}\\right\\rbrack } \\)\\( {\\xi }_{\\mathbf{t}\\left\\lbrack \\mathrm{{deg}}\\right\\rbrack } \\)\\( {\\xi }_{\\text{Scale }} \\)
10%100%0.1930.0180.009
20%100%0.1990.1330.076
30%100%0.5740.1880.175
40%96.4%0.9970.1590.122
50%90.7%1.3440.4420.169
60%87.1%1.1280.1340.137
70%81.4%0.8950.1430.060
80%66.3%1.4950.3280.329
90%42.7%1.7490.1340.139
" + }, + { + "type": "table_caption", + "bbox": [ + 0.499, + 0.741, + 0.892, + 0.77 + ], + "angle": 0, + "content": "Table 2. Performance of the 4-point problem under a RANSAC scheme given different outlier ratios using the synthetic dataset." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.781, + 0.724, + 0.797 + ], + "angle": 0, + "content": "5.3. Real-world Experiments" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.801, + 0.892, + 0.877 + ], + "angle": 0, + "content": "In order to test the proposed technique on real-world data, we chose the LaMAR [22] dataset, which contains both indoor and outdoor images with illumination and semantic changes as well as dynamic objects. We used the image sequences captured by a multi-camera rig (HoloLens 2)." + }, + { + "type": "page_footnote", + "bbox": [ + 0.518, + 0.887, + 0.7, + 0.9 + ], + "angle": 0, + "content": "1https://lamar.ethz.ch/" + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.514, + 0.957 + ], + "angle": 0, + "content": "8161" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.086, + 0.088, + 0.28, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.287, + 0.088, + 0.481, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.49, + 0.088, + 0.685, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.692, + 0.089, + 0.887, + 0.207 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.084, + 0.208, + 0.28, + 0.324 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.288, + 0.208, + 0.481, + 0.324 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.49, + 0.208, + 0.684, + 0.324 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.692, + 0.208, + 0.887, + 0.324 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.084, + 0.325, + 0.28, + 0.46 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.288, + 0.325, + 0.481, + 0.46 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.49, + 0.325, + 0.684, + 0.46 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.692, + 0.325, + 0.887, + 0.46 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.461, + 0.892, + 0.503 + ], + "angle": 0, + "content": "Figure 6. Boxplot of the relative errors under increasing image noise with a maximum value of 1 pixel. Top Row: Rotation error in degree. Middle Row: Translation error in degree. Bottom Row: Translation scale error. From left column to right column are general motion, sideways motion, forward motion and semi-pure translation, respectively." + }, + { + "type": "table", + "bbox": [ + 0.082, + 0.515, + 0.89, + 0.624 + ], + "angle": 0, + "content": "
SolverSuccess Rate (%)# of real sols. (# of positive real sols.)GPU-HC Timings (ms)Mean Julia Timings (ms) (8-core CPU)Julia GPU-HC
minmaxmedianmeanminmaxmedianmean
4-point (DP)99.7834(4)93(12)68(8)68.5(8.1)9.632.816.817.4428.2624.6×
4-point (SP)99.0632(2)89(10)52(5)53.2(5.1)5.315.77.27.358.7×
6-line (DP)98.67521398787.72.972.435.434.1110332.3×
6-line (SP)97.63481208482.45.215.47.17.2153.2×
" + }, + { + "type": "table_caption", + "bbox": [ + 0.215, + 0.632, + 0.747, + 0.646 + ], + "angle": 0, + "content": "Table 3. Success rate of finding the true solutions and the timings of solving the problems." + }, + { + "type": "image", + "bbox": [ + 0.085, + 0.659, + 0.466, + 0.756 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.758, + 0.47, + 0.787 + ], + "angle": 0, + "content": "Figure 7. An example of four images from the LaMAR CAB dataset captured by a multi-camera rig with four cameras." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.795, + 0.471, + 0.903 + ], + "angle": 0, + "content": "It has a specialized large field-of-view (FOV) multi-camera tracking rig with four cameras. In general, this dataset contains three large scale sequences including: (i) HGE, the ground floor of a historic university building consists of numerous large halls and broad esplanades on either side with \\(18000m^2\\). (ii) CAB, a multi-story office building that features a variety of small and large offices, a kitchen, stor" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.662, + 0.892, + 0.844 + ], + "angle": 0, + "content": "age rooms, and two courtyards with \\(12000m^2\\). (iii) LIN, several blocks of an ancient town, characterized by shops, restaurants, and narrow passageways with \\(15000m^2\\). To setup the experiments we extracted triplets of multi-camera images from the mapping set, where the ground-truth poses are available. From each trajectory in the mapping set we select consecutive triplets satisfying the following criteria; the distance between consecutive rigs is in \\([0.2m, 5m]\\) and at least two image pairs have more than 50 matches. This yielded in total 1280 (CAB), 1537 (HGE) and 2213 (LIN) triplets for evaluation. Pairwise 2d-2d matches are established using the SIFT[16] implementation in [23]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.892, + 0.903 + ], + "angle": 0, + "content": "Since there are no related solvers for generalized three-view relative pose problem, we only compare the proposed 4-point solver with the two-view 6-point solver [25]." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8162" + } + ], + [ + { + "type": "image_caption", + "bbox": [ + 0.18, + 0.09, + 0.289, + 0.1 + ], + "angle": 0, + "content": "Rotation error CDF" + }, + { + "type": "image", + "bbox": [ + 0.095, + 0.1, + 0.344, + 0.231 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.451, + 0.09, + 0.558, + 0.1 + ], + "angle": 0, + "content": "Rotation error CDF" + }, + { + "type": "image", + "bbox": [ + 0.365, + 0.1, + 0.612, + 0.23 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.721, + 0.09, + 0.829, + 0.1 + ], + "angle": 0, + "content": "Rotation error CDF" + }, + { + "type": "image", + "bbox": [ + 0.635, + 0.1, + 0.882, + 0.231 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.179, + 0.235, + 0.294, + 0.244 + ], + "angle": 0, + "content": "Translation error CDF" + }, + { + "type": "image", + "bbox": [ + 0.099, + 0.244, + 0.341, + 0.368 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.45, + 0.235, + 0.564, + 0.244 + ], + "angle": 0, + "content": "Translation error CDF" + }, + { + "type": "image", + "bbox": [ + 0.37, + 0.244, + 0.612, + 0.368 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.72, + 0.235, + 0.834, + 0.244 + ], + "angle": 0, + "content": "Translation error CDF" + }, + { + "type": "image", + "bbox": [ + 0.64, + 0.244, + 0.882, + 0.368 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.191, + 0.373, + 0.279, + 0.384 + ], + "angle": 0, + "content": "Scale error CDF" + }, + { + "type": "image", + "bbox": [ + 0.095, + 0.383, + 0.341, + 0.512 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.461, + 0.373, + 0.549, + 0.383 + ], + "angle": 0, + "content": "Scale error CDF" + }, + { + "type": "image", + "bbox": [ + 0.365, + 0.383, + 0.612, + 0.512 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.732, + 0.373, + 0.819, + 0.383 + ], + "angle": 0, + "content": "Scale error CDF" + }, + { + "type": "image", + "bbox": [ + 0.635, + 0.382, + 0.882, + 0.512 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.218, + 0.52, + 0.251, + 0.53 + ], + "angle": 0, + "content": "CAB" + }, + { + "type": "image_caption", + "bbox": [ + 0.489, + 0.52, + 0.522, + 0.53 + ], + "angle": 0, + "content": "HGE" + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.532, + 0.892, + 0.56 + ], + "angle": 0, + "content": "Figure 8. The cumulative distribution functions of the rotation, translation and scale errors. Being accurate is interpreted as a curve close to the top-left corner." + }, + { + "type": "table", + "bbox": [ + 0.086, + 0.569, + 0.462, + 0.704 + ], + "angle": 0, + "content": "
LaMARSolver\\( \\xi_R \\)\\( \\xi_t \\)\\( \\xi_S \\)InlierIter
CAB4-point0.541.650.63329105
6-point0.946.510.73317189
HGE4-point0.583.120.8039299
6-point0.978.250.85387193
LIN4-point0.462.010.72573100
6-point0.784.860.81535199
" + }, + { + "type": "table_caption", + "bbox": [ + 0.076, + 0.713, + 0.47, + 0.741 + ], + "angle": 0, + "content": "Table 4. The median errors, the number of inliers and the number of RANSAC iterations on the LaMAR dataset." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.471, + 0.901 + ], + "angle": 0, + "content": "To make a fair comparison, we use the solvers in a simple RANSAC framework with a maximum number of RANSAC iterations set to 500. The inlier-outlier threshold is set to 2 pixels. In Fig. 8, we show the cumulative distribution functions (CDF) of the rotation (in degrees), translation (in degrees) and scale errors on the three tested datasets. Being accurate is interpreted as a curve close to the top-left corner. The median errors are reported in Table 4. The proposed solver leads to more accurate results, more inliers and fewer iterations than the compared two-view method. Due" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.571, + 0.892, + 0.617 + ], + "angle": 0, + "content": "to the lack of space we only show the results using intra correspondences. Results for inter correspondences and mean errors are shown in the supplementary material." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.619, + 0.892, + 0.664 + ], + "angle": 0, + "content": "Limitations. The main limitation is that the refinement step is currently done in CPU. We will consider to include the refinement in the GPU computation in the future." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.666, + 0.619, + 0.681 + ], + "angle": 0, + "content": "6. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.687, + 0.892, + 0.853 + ], + "angle": 0, + "content": "We discuss minimal cases of generalized three-view relative pose estimation. In particular, we propose GPH-HC based solvers to the 4-point and 6-line cases. Experiments on thousands of image pairs from publicly available datasets show that the proposed three-view 4-point solver is superior to the state-of-the-art two-view 6-point solver. One goal of future research is to use the technique proposed in [11] to improve the efficiency. We believe that the proposed method is promising and will be a good complement to existing methods to improve the accuracy and stability of the structure from motion systems." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.892, + 0.9 + ], + "angle": 0, + "content": "Acknowledgements. VL, KÅ received funding from ELLIIT. Kimia and Chien gratefully acknowledge the support of NSF award 1910530." + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.957 + ], + "angle": 0, + "content": "8163" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.174, + 0.106 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.115, + 0.47, + 0.171 + ], + "angle": 0, + "content": "[1] Paul Breiding and Sascha Timme. HomotopyContinuation.jl: A Package for Homotopy Continuation in Julia. In International Congress on Mathematical Software, pages 458-465. Springer, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.172, + 0.472, + 0.253 + ], + "angle": 0, + "content": "[2] Chiang-Heng Chien, Hongyi Fan, Ahmad Abdelfattah, Elias Tsigaridas, Stanimire Tomov, and Benjamin Kimia. GPU-based homotopy continuation for minimal problems in computer vision. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 15765-15776, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.256, + 0.471, + 0.324 + ], + "angle": 0, + "content": "[3] Chiang-Heng Chien, Hongyi Fan, Ahmad Abdelfattah, Elias Tsigaridas, Stanimire Tomov, and Benjamin Kimia. Parallel path tracking for homotopy continuation using GPU. In Proceedings of the International Symposium on Symbolic and Algebraic Computation, 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.326, + 0.47, + 0.353 + ], + "angle": 0, + "content": "[4] David A. Cox, John Little, and Donal O'shea. Using algebraic geometry. Springer Science & Business Media, 2006." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.354, + 0.47, + 0.409 + ], + "angle": 0, + "content": "[5] Timothy Duff, Kathlen Kohn, Anton Leykin, and Tomas Pajdla. PLMP - Point-Line Minimal Problems in Complete Multi-View Visibility. In IEEE/CVF International Conference on Computer Vision (ICCV), 2019." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.41, + 0.47, + 0.492 + ], + "angle": 0, + "content": "[6] Ricardo Fabbri, Timothy Duff, Hongyi Fan, Margaret H. Regan, David da C. de Pinho, Elias Tsigaridas, Charles W. Wampler, Jonathan D. Hauenstein, Peter J. Giblin, Benjamin Kimia, Anton Leykin, and Tomas Pajdla. Trifocal Relative Pose From Lines at Points. Trans. Pattern Analysis and Machine Intelligence (PAMI), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.494, + 0.47, + 0.548 + ], + "angle": 0, + "content": "[7] Martin A Fischler and Robert C Bolles. Random sample consensus: a paradigm for model fitting with applications to image analysis and automated cartography. Communications of the ACM, 1981." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.551, + 0.469, + 0.605 + ], + "angle": 0, + "content": "[8] Jonathan D Hauenstein and Margaret H Regan. Adaptive strategies for solving parameterized systems using homotopy continuation. Applied Mathematics and Computation, 332:19-34, 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.607, + 0.469, + 0.647 + ], + "angle": 0, + "content": "[9] Robert J. Holt and Arun N. Netravali. Motion and structure from line correspondences: Some further results. International Journal of Imaging Systems and Technology, 1994." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.649, + 0.469, + 0.703 + ], + "angle": 0, + "content": "[10] Hongdong Li, Richard Hartley, and Jae-hak Kim. A linear approach to motion estimation using generalized camera models. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2008." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.705, + 0.469, + 0.759 + ], + "angle": 0, + "content": "[11] Petr Hruby, Timothy Duff, Anton Leykin, and Tomas Pajdla. Learning to Solve Hard Minimal Problems. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.761, + 0.469, + 0.802 + ], + "angle": 0, + "content": "[12] Zuzana Kukelova, Martin Bujnak, and Tomas Pajdla. Automatic generator of minimal problem solvers. In European Conference on Computer Vision (ECCV), 2008." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.804, + 0.469, + 0.858 + ], + "angle": 0, + "content": "[13] Viktor Larsson, Kalle Åström, and Magnus Oskarsson. Efficient solvers for minimal problems by syzygy-based reduction. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2017." + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.86, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[14] Viktor Larsson, Magnus Oskarsson, Kalle Åström, Alge Wallis, Zuzana Kukelova, and Tomas Pajdla. Beyond gröbner bases: Basis selection for minimal solvers. In" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.115, + 0.472, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2018." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.122, + 0.892, + 0.177 + ], + "angle": 0, + "content": "[15] Gim Hee Lee, Marc Pollefeys, and Friedrich Fraundorfer. Relative Pose Estimation for a Multi-camera System with Known Vertical Direction. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2014." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.179, + 0.892, + 0.219 + ], + "angle": 0, + "content": "[16] David G Lowe. Distinctive image features from scale-invariant keypoints. International Journal of Computer Vision (IJCV), 2004." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.221, + 0.892, + 0.276 + ], + "angle": 0, + "content": "[17] Branislav Micusik and Tomas Pajdla. Autocalibration & 3d reconstruction with non-central catadioptric cameras. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2004." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.278, + 0.892, + 0.317 + ], + "angle": 0, + "content": "[18] Alexander Morgan. Solving polynomial systems using continuation for engineering and scientific problems. SIAM, 2009." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.321, + 0.892, + 0.361 + ], + "angle": 0, + "content": "[19] David Nister and Frederik Schaffalitzky. Four Points in Two or Three Calibrated Views: Theory and Practice. International Journal of Computer Vision, 2006." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.364, + 0.892, + 0.404 + ], + "angle": 0, + "content": "[20] Robert Pless. Using many cameras as one. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2003." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.407, + 0.892, + 0.447 + ], + "angle": 0, + "content": "[21] Long Quan, Bill Triggs, and Bernard Mourrain. Some Results on Minimal Euclidean Reconstruction from Four Points. Journal of Mathematical Imaging and Vision, 2006." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.449, + 0.892, + 0.518 + ], + "angle": 0, + "content": "[22] Paul-Edouard Sarlin, Mihai Dusmanu, Johannes L. Schonberger, Pablo Speciale, Lukas Gruber, Viktor Larsson, Ondrej Miksik, and Marc Pollefeys. LaMAR: Benchmarking Localization and Mapping for Augmented Reality. In European Conference on Computer Vision (ECCV), 2022." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.52, + 0.892, + 0.56 + ], + "angle": 0, + "content": "[23] Johannes L Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2016." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.563, + 0.892, + 0.603 + ], + "angle": 0, + "content": "[24] Andrew J Sommese and Charles W Wampler. The Numerical solution of systems of polynomials arising in engineering and science. World Scientific, 2005." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.605, + 0.892, + 0.646 + ], + "angle": 0, + "content": "[25] Henrik Stewenius, David Nister, Magnus Oskarsson, and Kalle Åström. Solutions to minimal generalized relative pose problems. In Workshop on omnidirectional vision, 2005." + }, + { + "type": "ref_text", + "bbox": [ + 0.504, + 0.648, + 0.892, + 0.689 + ], + "angle": 0, + "content": "[26] Peter Sturm. Multi-View Geometry for General Camera Models. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2005." + }, + { + "type": "list", + "bbox": [ + 0.504, + 0.093, + 0.892, + 0.689 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.483, + 0.945, + 0.516, + 0.956 + ], + "angle": 0, + "content": "8164" + } + ] +] \ No newline at end of file diff --git a/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/21f6bf16-a75f-4e22-8ec8-d9aabd4e98e3_origin.pdf b/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/21f6bf16-a75f-4e22-8ec8-d9aabd4e98e3_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..78dd229c90f990cff98bd9c5de45911a43ffdc44 --- /dev/null +++ b/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/21f6bf16-a75f-4e22-8ec8-d9aabd4e98e3_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:88df4208e83701f291d5dc7264ec43485ee1be2be1cf45be0b5f3e35b4229599 +size 3563742 diff --git a/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/full.md b/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/full.md new file mode 100644 index 0000000000000000000000000000000000000000..734369ac6a9d8b487305f310dc74de1466823385 --- /dev/null +++ b/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/full.md @@ -0,0 +1,384 @@ +# Minimal Solutions to Generalized Three-View Relative Pose Problem + +Yaqing Ding $^{1\dagger}$ , Chiang-Heng Chien $^{2\dagger}$ , Viktor Larsson $^{1}$ , Karl Åström $^{1}$ , Benjamin Kimia $^{2}$ $^{1}$ Centre for Mathematical Sciences, Lund University + $^{2}$ School of Engineering, Brown University + +# Abstract + +For a generalized (or non-central) camera model, the minimal problem for two views of six points has efficient solvers. However, minimal problems of three views with four points and three views of six lines have not yet been explored and solved, despite the efforts from the computer vision community. This paper develops the formulations of these two minimal problems and shows how state-of-the-art GPU implementations of Homotopy Continuation solver can be used effectively. The proposed methods are evaluated on both synthetic and real datasets, demonstrating that they are fast, accurate and that they improve on structure from motion estimations, when employed in an hypothesis and test setting. + +# 1. Introduction + +In both the central and the non-central camera models, an image point is in correspondence to a ray of a 3D point that projects to that image point. In the central camera model, each such ray goes through a common point, i.e., the camera centre, whereas in the non-central camera model, two such rays do not always intersect. One example of a non-central camera is the catadioptric camera, where one or more lenses and/or mirrors are combined in an optical system, [17]. Another example is a rig of multiple cameras, [20]. A typical use-case is a car or drone equipped with several cameras. Here it is possible to use all of the cameras as one generalized sensor. Generalized cameras offer several advantages over the standard pinhole camera for relative pose estimation. As shown in previous works [20, 25, 10, 15], structure from motion estimation with a generalized camera also gives the scale of the translation as well as the scale of the 3D model. In addition, since the system consists of multiple cameras, it is possible to configure the location of each camera so that a maximal field-of-view can be achieved to avoid blind spots. This, in turn, enables more robust image + +![](images/967268b135f7209fea3d4f2080b544ce85b523595ce129f0a96e4eb22b2c1f03.jpg) +Figure 1. An example of a multi-camera system with four standard pinhole cameras mounted on a car. + +feature detection and matching, which is a crucial procedure in relative pose estimation. Fig. 1 shows an example of a multi-camera system consisting of four pinhole cameras mounted on a car for relative pose estimation. + +Unlike the standard pinhole camera, the light rays from a generalized camera do not intersect at a single center of projection. This property makes it non-trivial to estimate the relative pose using a generalized camera. Pless [20] first formulated the light rays in a generalized camera as Plücker vectors and defined the generalized essential matrix. Based on the work of Pless, several solutions to the two-view generalized relative pose estimation have been proposed [26, 10, 25]. Among these solutions, the minimal solver with up to 64 solutions was proposed in [25]. This solver only needs 6 point correspondences which can significantly reduce the number of RANSAC [7] iterations than other solvers. Although the solvers to the two-view generalized relative pose problem are already mature, there are no solutions to the three-view case as the generalized three-view relative pose problem is extremely difficult to be formulated and solved. In general, three-view relative pose estimation needs fewer point correspondence and suffers from fewer degenerate cases than the two-view case. Moreover, three-view relative pose can be estimated only using the line correspondences. Hence, it has a great po + +
Point •Line →Quiver •→No. of Solutions
4-point400583
6-line060600
3-quiver0031008
2P3L230920
2P1L1Q2111472
4L1Q0411976
2L2Q0222240
+ +Table 1. Possible cases and number of solutions for the generalized three-view relative pose problem. Each row shows the number of necessary features and the number of solutions. We mainly focus on the first two cases in this paper since they are more practical and relevant. + +tential and can provide new ways to solve the relative pose problem. + +The generalized three-view relative pose problem has 12 degrees of freedom (6 for the two rotations and 6 for the two translations). It is well known that the most commonly used features for relative pose estimation are points, lines and quivers, where a quiver consists of one point with tangent direction (or one point with one line passing through this point). According to the analyses in [5, 6], point, line and quiver in three views can provide 3,2 and 4 constraints, respectively. In Table 1, we show that there are 7 possible minimal cases for generalized three-view relative pose estimation using the combination of the three features. We only assume that there is one line passing through the point, there will be much more cases if there are several lines passing through one point. + +In this paper, to estimate the generalized three-view relative pose, we focus on the first two cases in Table 1. We show detailed discussions on the formulations and the number of solutions for each case. The main contributions of this paper include: + +- We solve the generalized three-view relative pose problem using 4 points or 6 lines. Specifically, detailed problem formulation for the two cases are given, which are then converted into solving a squared system of polynomials. +- This allows us to develop a solver using HC (homotopy continuation) based on the state-of-the-art GPU-HC solver [2, 3]. This significantly improves the efficiency over the existing modern HC software. +- In extensive synthetic and real experiments we show an improvement of accuracy over the state-of-the-art two-view 6-point solver. The proposed 4-point solver is able to deal with semi-pure translation, which is degenerated for the two-view case. + +# 2. Related Work + +Three-view Relative Pose. Estimating the calibrated three-view relative pose from standard pinhole cameras has been well studied in the literature. In general, this problem has 11 degrees of freedom (DOF), and can be solved using 4 points [19, 21] or 6 lines [9]. Note that, both 4 points and 6 lines are over-determined for standard pinhole cameras, which makes it difficult to derive stable solvers. The only available solver for the 4-point problem was shown in [11], where the authors added an extra parameter to solve a relaxed version of the problem. To the best of our knowledge, there are no publicly available solvers for the 6-line problem. It was shown in [9] that there might be up to 600 solutions to three-view relative pose with 6 lines using pinhole cameras. While the problem of estimating the three-view relative pose from standard pinhole cameras has received a lot of attention, this does not hold for the generalized three-view relative pose problem. There is only a discussion on the possible number of solutions using 4 points in three generalized views [25]. + +Solving Polynomials. Most of the minimal problems in computer vision can be transformed into solving a system of polynomial equations. A straightforward way of solving a polynomial system is to use the Gröbner basis method [4] and generate a specific solver using an automatic generator, e.g., [12, 13, 14]. The Gröbner basis method and related automatic generators have been successfully used in many computer vision problems [14], showing promising results in terms of stability and efficiency. However, it's difficult to find a stable solution for large scale problems using the Gröbner basis technique, since we need to apply Gauss-Jordan elimination and eigenvalue decomposition to large size of matrices. Alternatively, homotopy continuation (HC) [24, 8], one of the promising numerical solver for polynomial equations, is able to handle systems that are out of the reach of the Gröbner basis methods. However, HC algorithms are known to be slow, impractical for many multiview geometry problems when a RANSAC loop is involved, e.g. trifocal relative pose estimation requires over 600 (ms) per correspondence in [6]. This issue has been tackled by GPU-HC [2, 3] where the design of the GPU implementation accelerate the speed in orders of magnitude, giving efficient and accurate estimations for many minimal problems. As there is no paper using GPU-HC to solve minimal problems in practice, this paper stands out as the first approach to leverage it as our solvers. + +# 3. Problem Statement + +As SO(3) is three-dimensional, and we set the first generalized camera to $[1\mid 0]$ , the parameter space of camera configurations for $n$ -view case has dimension $6n - 6$ . Since one point correspondence in three views gives three constraints, + +![](images/8bd0ca09d1ec8b29107a81e2ba5859e8123ff80f64bce0362e07f8a31eb64fe9.jpg) +Figure 2. The minimal problem of 4 points seen in three generalized cameras. In this example the generalized cameras are visualized as multi-camera systems. + +and one line correspondence in three views gives two constraints, we can find that 4 points and 6 lines in three views are two minimal cases. + +# 3.1. The 4-point Case + +Assuming that four points $\mathbf{X}_1, \mathbf{X}_2, \mathbf{X}_3, \mathbf{X}_4$ in the 3D space are observed by three generalized cameras (Figure 2). Note that, the four points $\{\mathbf{X}_1, \mathbf{X}_2, \mathbf{X}_3, \mathbf{X}_4\}$ can't be viewed from a single pinhole camera, i.e., the points need to be sampled from at least two cameras. Otherwise, the problem will be degenerated into the trifocal relative pose from a standard pinhole camera. The image points of the four 3D points in each view can be written as $\mathbf{x}_{1i}, \mathbf{x}_{2i}, \mathbf{x}_{3i}, \mathbf{x}_{4i}, i \in \{1, 2, 3\}$ . On the other hand, the rotation matrices and translation vectors that align the image points with the world coordinate are defined as $\{\mathbf{A}_{ki}, \boldsymbol{\tau}_{ki}\}$ . We formulate the depths of the image points in each generalized view as $\lambda_{1i}, \lambda_{2i}, \lambda_{3i}, \lambda_{4i}, i \in \{1, 2, 3\}$ . Due to the rigid motion, the distance between any two points in each view should be the same. Hence, we have + +$$ +\begin{array}{l} \left\| \lambda_ {1 1} \mathbf {A} _ {1 1} \mathbf {x} _ {1 1} + \boldsymbol {\tau} _ {1 1} - \lambda_ {2 1} \mathbf {A} _ {2 1} \mathbf {x} _ {2 1} - \boldsymbol {\tau} _ {2 1} \right\| ^ {2} \\ = \left\| \lambda_ {1 2} \mathbf {A} _ {1 2} \mathbf {x} _ {1 2} + \boldsymbol {\tau} _ {1 2} - \lambda_ {2 2} \mathbf {A} _ {2 2} \mathbf {x} _ {2 2} - \boldsymbol {\tau} _ {2 2} \right\| ^ {2} \tag {1} \\ \end{array} +$$ + +$$ +\begin{array}{l} \left\| \lambda_ {3 1} \mathbf {A} _ {3 1} \mathbf {x} _ {3 1} + \boldsymbol {\tau} _ {3 1} - \lambda_ {4 1} \mathbf {A} _ {4 1} \mathbf {x} _ {4 1} - \boldsymbol {\tau} _ {4 1} \right\| ^ {2} \\ = \left\| \lambda_ {4 3} \mathbf {A} _ {4 3} \mathbf {x} _ {4 3} + \boldsymbol {\tau} _ {4 3} - \lambda_ {4 4} \mathbf {A} _ {4 4} \mathbf {x} _ {4 4} - \boldsymbol {\tau} _ {4 4} \right\| ^ {2} \\ \end{array} +$$ + +In this case, we obtain 12 polynomials in 12 unknowns $\{\lambda_{1i},\lambda_{2i},\lambda_{3i},\lambda_{4i}\}$ . Based on [1], we find that there are up to 583 solutions. Once the depth parameters are computed, we let + +$$ +\mathbf {X} _ {k i} = \lambda_ {k i} \mathbf {A} _ {k i} \mathbf {x} _ {k i} + \boldsymbol {\tau} _ {k}, \tag {2} +$$ + +where $k \in \{1, 2, 3, 4\}$ and $i \in \{1, 2, 3\}$ . We have the following constraints + +$$ +\mathbf {X} _ {k 2} = \mathbf {R} _ {2} \mathbf {X} _ {k 1} + \mathbf {t} _ {2}. \tag {3} +$$ + +By eliminating the translation parameters, we have + +$$ +\mathbf {X} _ {k 2} - \mathbf {X} _ {1 2} = \mathbf {R} _ {2} \left(\mathbf {X} _ {k 1} - \mathbf {X} _ {1 1}\right), k \in \{2, 3, 4 \}. \tag {4} +$$ + +Hence, the rotation matrix $\mathbf{R}_2$ can be found by + +$$ +\mathbf {R} _ {2} = \mathbf {B} _ {2} \mathbf {B} _ {1} ^ {- 1}, +$$ + +$$ +\mathbf {B} _ {2} = \left[ \mathbf {X} _ {2 2} - \mathbf {X} _ {1 2}, \mathbf {X} _ {3 2} - \mathbf {X} _ {1 2}, \mathbf {X} _ {4 2} - \mathbf {X} _ {1 2} \right], \tag {5} +$$ + +$$ +\mathbf {B} _ {1} = \left[ \mathbf {X} _ {2 1} - \mathbf {X} _ {1 1}, \mathbf {X} _ {3 1} - \mathbf {X} _ {1 1}, \mathbf {X} _ {4 1} - \mathbf {X} _ {1 1} \right]. +$$ + +Then the translation can be computed using (3). Similarly, we can obtain $\mathbf{R}_3$ , $\mathbf{t}_3$ . + +# 3.2. The 6-line Case + +Assuming that six lines $\mathbf{L}_1, \mathbf{L}_2, \dots, \mathbf{L}_6$ in the 3D space are observed by three generalized cameras. The projections of the lines in each view can be written as $l_{1i}, l_{2i}, \dots, l_{6i}, i \in \{1, 2, 3\}$ . The line and the camera center define a plane which passes through the origin of the local camera coordinate. In this case, the plane in each camera coordinate can be formulated as + +$$ +\boldsymbol {\pi} _ {k i} = \left[ \boldsymbol {l} _ {k i}; 0 \right]. \tag {6} +$$ + +In addition, we let the $4 \times 4$ transformation matrices that align the planes with the world coordinate as + +$$ +\mathbf {C} _ {k i} = \left[ \begin{array}{c c} \mathbf {A} _ {k i} & \boldsymbol {\tau} _ {k i} \\ \mathbf {0} & 1 \end{array} \right]. \tag {7} +$$ + +The planes in three views which are defined by one 3D line should intersect at this line, in this case, we can obtain the following constraints + +$$ +\begin{array}{l} \operatorname {r a n k} \left[ \mathbf {P} _ {1} ^ {\top} \mathbf {C} _ {k} ^ {\top} \boldsymbol {\pi} _ {k 1} \mid \mathbf {P} _ {2} ^ {\top} \mathbf {C} _ {k} ^ {\top} \boldsymbol {\pi} _ {k 2} \mid \mathbf {P} _ {3} ^ {\top} \mathbf {C} _ {k} ^ {\top} \boldsymbol {\pi} _ {k 3} \right] \leq 2, \tag {8} \\ k \in \{1, 2, 3, 4, 5, 6 \}, \\ \end{array} +$$ + +where matrix $\mathbf{P}_i$ is defined as + +$$ +\mathbf {P} _ {i} = \left[ \begin{array}{c c} \mathbf {R} _ {i} & \boldsymbol {t} _ {i} \\ \mathbf {0} & 1 \end{array} \right], i \in \{1, 2, 3 \}. \tag {9} +$$ + +Based on (9), we can obtain $6 * \mathrm{C}_3^4 = 24$ polynomials in the rotation and translation parameters. If we consider the constraints that only contain the rotation components, we have 6 constraints in the rotation parameters + +$$ +\begin{array}{l} \det \left[ \mathbf {A} _ {k 1} ^ {\top} l _ {k 1} \mid \mathbf {R} _ {2} ^ {\top} \mathbf {A} _ {k 2} ^ {\top} l _ {k 2} \mid \mathbf {R} _ {3} ^ {\top} \mathbf {A} _ {k 3} ^ {\top} l _ {k 3} \right] = 0, \tag {10} \\ k \in \{1, 2, 3, 4, 5, 6 \}. \\ \end{array} +$$ + +In order to find the motion parameters, we introduce two formulations for the rotation matrix. + +Cayley parameterization. The major advantage lies in this formulation is that there remain only three variables for each rotation matrix: + +$$ +\mathbf {R} _ {2} = \frac {1}{\kappa_ {2}} \left[ \begin{array}{c c c} 1 + q _ {1} ^ {2} - q _ {2} ^ {2} - q _ {3} ^ {2} & 2 (q _ {1} q _ {2} - q _ {3}) & 2 (q _ {1} q _ {3} + q _ {2}) \\ 2 (q _ {1} q _ {2} + q _ {3}) & 1 - q _ {1} ^ {2} + q _ {2} ^ {2} - q _ {3} ^ {2} & 2 (q _ {2} q _ {3} - q _ {1}) \\ 2 (q _ {1} q _ {3} - q _ {2}) & 2 (q _ {2} q _ {3} + q _ {1}) & 1 - q _ {1} ^ {2} - q _ {2} ^ {2} + q _ {3} ^ {2} \end{array} \right] +$$ + +$$ +\mathbf {R} _ {3} = \frac {1}{\kappa_ {3}} \left[ \begin{array}{c c c} 1 + q _ {4} ^ {2} - q _ {5} ^ {2} - q _ {6} ^ {2} & 2 (q _ {4} q _ {5} - q _ {6}) & 2 (q _ {4} q _ {6} + q _ {5}) \\ 2 (q _ {4} q _ {5} + q _ {6}) & 1 - q _ {4} ^ {2} + q _ {5} ^ {2} - q _ {6} ^ {2} & 2 (q _ {5} q _ {6} - q _ {4}) \\ 2 (q _ {4} q _ {6} - q _ {5}) & 2 (q _ {5} q _ {6} + q _ {4}) & 1 - q _ {4} ^ {2} - q _ {5} ^ {2} + q _ {6} ^ {2} \end{array} \right], +$$ + +where $\kappa_{2} = 1 + q_{1}^{2} + q_{2}^{2} + q_{3}^{2}$ , $\kappa_{3} = 1 + q_{4}^{2} + q_{5}^{2} + q_{6}^{2}$ , note that this formulation is unstable in case of Cayley degenerate rotations ( $\kappa_{2}, \kappa_{3} = 0$ ). However, the probability for the degenerate case is quite low in practice, and this formulation has been successfully used in many computer vision problems [13]. Since the constraints (10) are homogenous in the rotation matrices, the scale factors $\kappa_{2}, \kappa_{3}$ can be omitted. In this case, we can obtain 6 quartic polynomials in 6 unknowns $\{q_{1}, q_{2}, \dots, q_{6}\}$ . The monodromy solver in [1] shows that there are up to 600 solutions. Once the rotation parameters are computed, we need to substitute them into (8) and obtain six linear equations in the translation parameters. The translation $\mathbf{t}_{2}$ , $\mathbf{t}_{3}$ can be uniquely obtained. + +Homogeneous rotation matrix. On the other hand, since constraints (8) are invariant to the scale of the rotation matrices, we can use 8 parameters to formulate the rotation up to a scale factor (assuming the first element to be 1) + +$$ +\mathbf {R} _ {2} = \left[ \begin{array}{c c c} 1 & r _ {2} & r _ {3} \\ r _ {4} & r _ {5} & r _ {6} \\ r _ {7} & r _ {8} & r _ {9} \end{array} \right], \mathbf {R} _ {3} = \left[ \begin{array}{c c c} 1 & r _ {1 1} & r _ {1 2} \\ r _ {1 3} & r _ {1 4} & r _ {1 5} \\ r _ {1 6} & r _ {1 7} & r _ {1 8} \end{array} \right]. +$$ + +The elements $\{r_2, r_2, \ldots, r_9\}$ should satisfy the following constraints + +$$ +\begin{array}{l} r _ {2} r _ {8} + r _ {3} r _ {9} + r _ {7} = 0, r _ {2} r _ {5} + r _ {3} r _ {6} + r _ {4} = 0, \\ r _ {4} r _ {6} + r _ {7} r _ {9} + r _ {3} = 0, r _ {4} r _ {5} + r _ {7} r _ {8} + r _ {2} = 0, \\ r _ {5} ^ {2} + r _ {6} ^ {2} - r _ {7} ^ {2} - 1 = 0. \\ \end{array} +$$ + +In this case, we can obtain 16 quadratic polynomials in 16 unknowns $\{r_2,r_3,\dots,r_{18}\}$ . Similar to the Cayley parameterization, this formulation is unstable in case of degenerate rotations $(r_1,r_{10} = 0)$ . Although such degenerate cases can be avoided by using unit quaternion formulation, it will result in more parameters than the Cayley parameterization and the system of polynomials has 2-fold symmetry. In order to derive more efficient solvers, we only discuss Cayley parameterization and homogeneous rotation matrix formulation in this paper. + +Geometric Interpretation of (10). The line projection with the camera center define a plane, and this plane gives a line at infinity. Since the three lines in three views should correspond to the same 3D line, the three lines at infinity should intersect at the same point. In this case, we can obtain constraint (10). + +# 3.3. Degenerate Case + +A detailed analysis of the degeneracies for generalized two-view relative pose estimation has been shown in [10, 15]. The degenerated case is slightly different in + +generalized three-view relative pose problem. In our case, we found that if the multi-camera system undergoes pure translation $(\mathbf{R}_2 = \mathbf{R}_3 = \mathbf{I})$ with only intra-camera correspondences, our solvers can not recover the scale of the translation. However, if we only have $\mathbf{R}_2 = \mathbf{I}$ or $\mathbf{R}_3 = \mathbf{I}$ , our solvers can still recover the translation with scale factor. + +# 4. Polynomial System Solver + +![](images/143b08a095f7f6656cad26d73d7121f34744207038f5ac6349058b01efbcd214.jpg) +Figure 3. A track (curve) of a Homotopy Continuation algorithm showing $H(X, t)$ in black, along with one prediction (red) and one correction (blue). + +Homotopy Continuation: The idea of Homotopy Continuation (HC) [18, 24] is to evolve the solutions of one polynomial system $G$ , the "start system", to discover the solutions of another system $F$ , the "target system". Let $X = (x_{1}, x_{2}, \ldots, x_{M})$ represent $M$ unknowns. Let $F(X)$ be a system of $N$ polynomial equations $F = (f_{1}, f_{2}, \ldots, f_{N})$ . Let $G(x)$ , $G = (g_{1}, g_{2}, \ldots, g_{N})$ be the "start system" whose solutions are all known. The idea of HC is to construct a series of intermediate polynomial systems $H(X, t)$ , $H = (H_{1}, H_{2}, \ldots, H_{N})$ ; where $H(X, 0) = G(X)$ and $H(X, 1) = F(X)$ , e.g., via linear interpolation: + +$$ +H (x, t) = (1 - t) G (x) + t F (x), \quad t \in [ 0, 1 ]. \tag {11} +$$ + +The basic idea is to find the solution of $H(X, t + \Delta t)$ from the solution of $H(X, t)$ . Figure 3 illustrates the idea for one solution and one unknown. The black curve is the locus of the solution $X(t)$ of $H(X, t)$ , the homotopy curve, where $X_0$ is the known solution of $G(X)$ and $X_1$ is the desired solution of $F(X)$ . We track solution $X_1$ from $X_0$ in a number of small steps, each consisting of a prediction and a correction step. Prediction uses a first-order Taylor expansion to estimate $X$ at $t + \Delta t$ in the form of + +$$ +X ^ {*} (t + \Delta t) = X (t) + \frac {d X}{d t} \Delta t, \tag {12} +$$ + +where $X^{*}$ is the first order estimation of $X(t + \Delta t)$ . We obtain $\frac{dX}{dt}$ by differentiating $H(X(t),t)$ , i.e., + +$$ +\frac {\partial H}{\partial X} \frac {d X}{d t} + \frac {\partial H}{\partial t} = 0 \longrightarrow \frac {d X}{d t} = - \left(\frac {\partial H}{\partial X}\right) ^ {- 1} \frac {\partial H}{\partial t}, \tag {13} +$$ + +where $J = \frac{\partial H}{\partial x}$ is the $M \times N$ Jacobian of $H$ wrt $X$ , giving + +$$ +X ^ {*} (t + \Delta t) = X (t) - \left(\frac {\partial H}{\partial X}\right) ^ {- 1} \frac {\partial H}{\partial t} \Delta t. \tag {14} +$$ + +The first-order estimation of $X^{*}$ from $X(t)$ is known as the prediction step (Figure 3) which can be further improved using a higher-order method such as a fourth order Runge-Kutta. Followed by a correction step which helps improve the prediction, Newton's update $X^{*}(t + \Delta t)$ to $\hat{X}(t + \Delta t)$ is used, i.e., + +$$ +H \left(X ^ {*}, t + \Delta t\right) + \frac {\partial H}{\partial X} \left(X ^ {*}, t + \Delta t\right) \left(\hat {X} - X ^ {*}\right) = 0, \tag {15} +$$ + +giving the estimate $\hat{X}$ in the form of + +$$ +\hat {X} = X ^ {*} - \left(\frac {\partial H}{\partial X}\right) ^ {- 1} \left(X ^ {*}, t + \Delta t\right) H \left(X ^ {*}, t + \Delta t\right). \tag {16} +$$ + +The pairs of prediction and correction numerically evolve $X_0$ as the solution of $G(X)$ to $X_1$ as the solution of $F(X)$ . HC algorithms find all the solutions (up to some approximation) with probability one given a good start system which can be provided easily by a monodromy solver [1]. In many computer vision applications, a good start system usually needs to be created once as multiple target systems correspond to different target parameters can be solved from the same start system under a RANSAC loop. + +GPU-HC: The iterative nature of HC prevents it from being practically used. The GPU implementation in [2, 3] parallelizes (i) HC paths and (ii) the evaluations of $\frac{\partial H}{\partial X}$ , $\frac{\partial H}{\partial t}$ , and $H$ , Equations (13) and (16) to enable HC efficiently solves problems whose complexity has far evaded a practical solution. We thus use GPU-HC as our minimal problem solver, giving promising results in our experiments. + +GPU-HC Solution Refinement: Since GPU computation is memory-bound, extending numerical precision in GPU computation would significantly drag down efficiency. To obtain high numerical accuracy while avoiding slowdown, Levenberg-Marquardt algorithm using double precision is used, followed by GPU-HC using single precision for solution refinement. This refinement step can be done in CPU side efficiently as only partial GPU-HC solutions are necessary to be refined, i.e., real solutions in the 6-line problem or real and positive solutions in the 4-point problem. + +# 5. Experiments + +To demonstrate that the proposed solvers work well in practice, we conduct extensive experiments on both synthetic and real-world data with multi-camera system configuration. Experiments are run on a 16-Core 3.6GHz Intel i7-11700K CPU and a NVIDIA Titan V GPU. + +For both synthetic and real experiments, the solver's performance is evaluated by the following criteria: + +$$ +\begin{array}{l} \xi_ {\mathbf {R} [ \mathrm {d e g} ]} = 2 \arcsin \left(\frac {\| \mathbf {R} _ {g t} - \mathbf {R} _ {e} \|}{2 \sqrt {2}}\right), \\ \xi_ {\mathbf {t} [ \mathrm {d e g} ]} = 2 \arcsin \left(\frac {1}{2} \left\| \frac {\mathbf {t} _ {e}}{\| \mathbf {t} _ {e} \|} - \frac {\mathbf {t} _ {g}}{\| \mathbf {t} _ {g} \|} \right\|\right), \\ \xi_ {\text {S c a l e}} = \operatorname {a b s} \left(\| \mathbf {t} _ {e} \| / \| \mathbf {t} _ {g t} \| - 1\right), \\ \end{array} +$$ + +where $\xi_{\mathbf{R}}$ , $\xi_{\mathbf{t}}$ , and $\xi_{\mathrm{Scale}}$ are the angle difference in rotation, direction difference in translation and relative scale error, respectively. $\mathbf{R}_{gt}, \mathbf{t}_{gt}$ are the ground truth rotation and translation, and $\mathbf{R}_e, \mathbf{t}_e$ are the estimated rotation and translation, respectively. All the norms are Frobenius norm. Note that, computing the rotation angle error and the translation direction error based on the $\arccos\left((\operatorname{trace}(\mathbf{R}_{\mathrm{gt}}^\top \mathbf{R}_{\mathrm{e}}) - 1)/2\right)$ is simpler. However, it's not the best choice. For example, if the relative angle between the rotation matrices is small, $\left((\operatorname{trace}(\mathbf{R}_{\mathrm{gt}}^\top \mathbf{R}_{\mathrm{e}}) - 1)/2\right)$ is close to unity in that case and the $\arccos$ is very sensitive to errors. Hence, it's better to compute angular errors using the $\arcsin$ formulation. Detailed comparisons between $\arcsin$ and $\arccos$ are shown in the supplementary material. + +# 5.1. Numerical Accuracy of the Solvers + +Although it has been reported in [2, 3] that GPU-HC provides promising and acceptable numerical accuracy in solving various minimal problems in computer vision, for the proposed problems to be usable the evaluation on polynomial residual is still necessary. Figure 4 top row shows the accuracy of (a) all GPU-HC converged solutions and (b) the converged solutions correspond to the ground truths, solving 6-line problem and 4-point problem using our synthetic dataset generating 10,000 real parameters for each problem. Both single precision (SP) and double precision (DP) are demonstrated, showing that the solver is able to provide less than $10^{-5}$ accurate results for the majority of the GPU-HC solutions. Nevertheless, if a refinement step is involved, significant shifts in the distributions of residuals can be observed, Figure 4 bottom row, where single precision solu + +![](images/d6b82679418a569165cafc6b33b73f03df1ff883338bdc50917e98762671e210.jpg) + +![](images/5d80cf1b275de1ada4719eb80a590656fda8398cdc8c176fe057c84755cf6ddd.jpg) + +![](images/595d8b5806d93541377dc477cf22a70792c2974174943537403f9e5954bfe3aa.jpg) +(a) + +![](images/c2c03cecc966503d9fb72029efa09bd2c851ebeed80e3d28ee6c48e0f6b43b76.jpg) +(b) +Figure 4. Numerical accuracy of GPU-HC from (a) all converged paths and (b) converged paths correspond to the true solution of the 4-points and 6-lines problems. Top Row: Original. Bottom Row: Refinement. + +tions are nearly as accurate as the double precision. + +# 5.2. Synthetic Evaluation + +![](images/c60b7a8d33ac9e0e28ad0006c3807866adf14ca23c5531b6d305796371542695.jpg) + +![](images/50e8d6d67d33d7178aebfeaa045c5facaf20f07c9d6711598e78e24f12ab4386.jpg) + +![](images/ad645e44c35c5f86e544be9d1e449e1ca98f50d5a4ef8329eaa97419eb202fd0.jpg) +Figure 5. Relative errors with noise-free data under random points and movement. Top Row: The 4-point solver. Bottom Row: The 6-line solver. + +![](images/a660c9e32cc5595fdb69d8c38ac399183993ecd9ae872ca1a1497cc9fc6b7cc0.jpg) + +In this section, we evaluate the numerical stability and the noise resilience of the proposed solvers. We simulated a multi-camera system with six cameras, and the focal length of each pinhole camera is set to $1000\mathrm{px}$ . To generate the scene we uniformly sample 3D points from the box $[-2,2]\times [-2,2]\times [3,6]$ in each camera's local coordinate system. Then based on two points we can generate lines in each camera. Finally these points and lines are transformed with a random but feasible rotation and translation. + +Stability. We randomly generated 1000 noise-free instances with different transformations. Figure 5 top row shows the distribution of the $\log_{10}$ relative errors of the 4-point solver, and Figure 5 bottom row shows the distribution of the $\log_{10}$ relative errors of the 6-line solver, respectively. We can see that both solvers are quite stable. + +Noise resilience. In this experiment, we focused on four practical motions: general motion, forward motion (along the $z$ -axis), sideways motion (along the $x$ -axis), and semipure translation $(\mathbf{R}_2 = \mathbf{I})$ . Fig. 6 shows the performance of the proposed 4-point solver and 6-line solver under increasing image noise with different standard deviation. We can see that the 4-point solver has almost similar error distributions for the four motions. The only difference is that the translation direction error is slightly larger under sideways motion and forward motion. Overall, the performance of the 4-point solver is stable under different motions with increasing image noise. By contrast, the 6-line solver is more sensitive to image noise, especially the translation direction error. This is possibly due to the noise that we added to the end points. If the points are close to each other, very small noise in the end points may result in extremely large errors in the line direction. Since the 6-line solver is sensitivity + +to noise, we will focus on the performance of the 4-point solver in the real experiments. + +Complexity analysis and running times. The success rate of finding the HC solutions correspond to the ground truths and the overall timings of our GPU-HC solver is shown in Table 3. Typically, using double precision would give a slowdown in speed compared to single precision, but there are times where double precision is faster than single precision, e.g., the minimum GPU-HC time of 6-line problem. This is because the required number of HC steps is lesser when double precision is used which converges HC tracks faster. The speedup compared to Julia 8-core CPU HC solver in the table also demonstrate the benefit of using GPU-HC, which gives more than $150 \times$ speedup and $58 \times$ speedup for single precision of 6-line and 4-point problems, respectively, enabling real-time computation. + +Success rate and accuracy under a RANSAC scheme. Table 2 shows the RANSAC experiment of the 4-point problem using the synthetic dataset with image size $1000 \times 1000$ pixels. Among the projections of the 1000 synthetic generated scene points, the inliers are corrupted by uniformly distributed noise within a $7 \times 7$ window, while the outliers are corrupted by shifting the point by at least half the image size. 80 iterations is used for every case running 1000 times, and a successful RANSAC estimation is decided if $\xi_{\mathbf{R}[\mathrm{deg}]} < 2$ degrees. The table shows only $\mathbf{R}_2$ , $\mathbf{t}_2$ , and $\mathbf{s}_2$ since they share similar accuracy with $\mathbf{R}_3$ , $\mathbf{t}_3$ , and $\mathbf{s}_3$ . The errors are the averaged accuracy of successful cases which show that below $70\%$ outlier ratio the success rate has more than $80\%$ , and as long as inlier points are picked, the estimation accuracy is very promising. + +
Outlier RatioSuccess Rate\( {\xi }_{\mathbf{R}\left\lbrack \mathrm{{deg}}\right\rbrack } \)\( {\xi }_{\mathbf{t}\left\lbrack \mathrm{{deg}}\right\rbrack } \)\( {\xi }_{\text{Scale }} \)
10%100%0.1930.0180.009
20%100%0.1990.1330.076
30%100%0.5740.1880.175
40%96.4%0.9970.1590.122
50%90.7%1.3440.4420.169
60%87.1%1.1280.1340.137
70%81.4%0.8950.1430.060
80%66.3%1.4950.3280.329
90%42.7%1.7490.1340.139
+ +Table 2. Performance of the 4-point problem under a RANSAC scheme given different outlier ratios using the synthetic dataset. + +# 5.3. Real-world Experiments + +In order to test the proposed technique on real-world data, we chose the LaMAR [22] dataset, which contains both indoor and outdoor images with illumination and semantic changes as well as dynamic objects. We used the image sequences captured by a multi-camera rig (HoloLens 2). + +![](images/e80d3067e31837f045a56494858c800afa262c28eccbc111417337c5a3c69804.jpg) + +![](images/97dbae3c86f767a35572132213b9dbf519877e07d55486f044a3d6bcb87fb7d6.jpg) + +![](images/2566f398addc4ce68565ba3c2d847f95e21f919b2920e31d245ff8266da530d6.jpg) + +![](images/6c73f3f6280722a7a4593402a56ead53ecbaa43cfb4ab86657baef2269ccc816.jpg) + +![](images/8bee8e685e0145f1b460b685051966f1e3bfc45b94c63b9d439db50bbdf4bbae.jpg) + +![](images/34f6cd00b14068689e95e19adbccc35d8de864a52879c5a19500331914e7d6d8.jpg) + +![](images/2428c96a26cb7bf4e06bd4c3ed03ec7d8e8265e902779042f700f65083bb2c89.jpg) + +![](images/cfe207372c97c4ee4afeaec9dfc72e54ddf01335ffe7efea0bb9fc5c4b54cb23.jpg) + +![](images/6fb4aeab4b40531941b9da83a9c1448521e4c817e4231e06ac4dd460f5854cd1.jpg) +Figure 6. Boxplot of the relative errors under increasing image noise with a maximum value of 1 pixel. Top Row: Rotation error in degree. Middle Row: Translation error in degree. Bottom Row: Translation scale error. From left column to right column are general motion, sideways motion, forward motion and semi-pure translation, respectively. + +![](images/62d11d488f366568cbc720979b5bb7503b16c8b4b3e79a5b4e6f77579b1cf4a6.jpg) + +![](images/b55620d740c2305d83599c3183a0652cef5ad2db26107539e38de0a66ab2ecce.jpg) + +![](images/246dd04e0e2ef3ce6dadd514cb6c6dcac0d59b57fc5bb84128dc2787eaec3662.jpg) + +
SolverSuccess Rate (%)# of real sols. (# of positive real sols.)GPU-HC Timings (ms)Mean Julia Timings (ms) (8-core CPU)Julia GPU-HC
minmaxmedianmeanminmaxmedianmean
4-point (DP)99.7834(4)93(12)68(8)68.5(8.1)9.632.816.817.4428.2624.6×
4-point (SP)99.0632(2)89(10)52(5)53.2(5.1)5.315.77.27.358.7×
6-line (DP)98.67521398787.72.972.435.434.1110332.3×
6-line (SP)97.63481208482.45.215.47.17.2153.2×
+ +Table 3. Success rate of finding the true solutions and the timings of solving the problems. + +![](images/eed162769ab8ff218dc5e7f9898c721d9e7bcc80d24ce3095803f76adcdfb394.jpg) +Figure 7. An example of four images from the LaMAR CAB dataset captured by a multi-camera rig with four cameras. + +It has a specialized large field-of-view (FOV) multi-camera tracking rig with four cameras. In general, this dataset contains three large scale sequences including: (i) HGE, the ground floor of a historic university building consists of numerous large halls and broad esplanades on either side with $18000m^2$ . (ii) CAB, a multi-story office building that features a variety of small and large offices, a kitchen, stor + +age rooms, and two courtyards with $12000m^2$ . (iii) LIN, several blocks of an ancient town, characterized by shops, restaurants, and narrow passageways with $15000m^2$ . To setup the experiments we extracted triplets of multi-camera images from the mapping set, where the ground-truth poses are available. From each trajectory in the mapping set we select consecutive triplets satisfying the following criteria; the distance between consecutive rigs is in $[0.2m, 5m]$ and at least two image pairs have more than 50 matches. This yielded in total 1280 (CAB), 1537 (HGE) and 2213 (LIN) triplets for evaluation. Pairwise 2d-2d matches are established using the SIFT[16] implementation in [23]. + +Since there are no related solvers for generalized three-view relative pose problem, we only compare the proposed 4-point solver with the two-view 6-point solver [25]. + +![](images/b826bab8c9eab6bf88e0ca67da3a95153a3ddaf55496d24d95b9a3c7800eb588.jpg) +Rotation error CDF + +![](images/5b99f1455a59e229e7d64b22810db520ae40776ed4abc74c5bcac839b82a24b2.jpg) +Rotation error CDF + +![](images/514dba690399d98f4c468d334743c0d93b31db942adfc68768c8d6c03ed0f45e.jpg) +Rotation error CDF + +![](images/1d00a02b4777fa18067a25c39ef384a3161dc64669a503a2582b601ccf222f90.jpg) +Translation error CDF + +![](images/7b754157eeed04b8947d757534d360e5ba3c6d6833187c10a9e141a0f55b0f9b.jpg) +Translation error CDF + +![](images/821ab51c9a16a868cd20d18514fb454d4b5742653fa3384fd41e88829e814fe3.jpg) +Translation error CDF + +![](images/f0fddc3935c2d788fde28344571dbcf1310f8ce2e86611356ffdf619b953a29c.jpg) +Scale error CDF +CAB +Figure 8. The cumulative distribution functions of the rotation, translation and scale errors. Being accurate is interpreted as a curve close to the top-left corner. + +![](images/c6a28a8b98f151914c8a858c9b5d7d0b3cf1c124ca48f11914c7d8e52d004dd9.jpg) +Scale error CDF +HGE + +![](images/9ee0ecb8ea935533f270653fb5263c9427a8a7ddb076ee5ccdf88da048741966.jpg) +Scale error CDF + +
LaMARSolver\( \xi_R \)\( \xi_t \)\( \xi_S \)InlierIter
CAB4-point0.541.650.63329105
6-point0.946.510.73317189
HGE4-point0.583.120.8039299
6-point0.978.250.85387193
LIN4-point0.462.010.72573100
6-point0.784.860.81535199
+ +Table 4. The median errors, the number of inliers and the number of RANSAC iterations on the LaMAR dataset. + +To make a fair comparison, we use the solvers in a simple RANSAC framework with a maximum number of RANSAC iterations set to 500. The inlier-outlier threshold is set to 2 pixels. In Fig. 8, we show the cumulative distribution functions (CDF) of the rotation (in degrees), translation (in degrees) and scale errors on the three tested datasets. Being accurate is interpreted as a curve close to the top-left corner. The median errors are reported in Table 4. The proposed solver leads to more accurate results, more inliers and fewer iterations than the compared two-view method. Due + +to the lack of space we only show the results using intra correspondences. Results for inter correspondences and mean errors are shown in the supplementary material. + +Limitations. The main limitation is that the refinement step is currently done in CPU. We will consider to include the refinement in the GPU computation in the future. + +# 6. Conclusion + +We discuss minimal cases of generalized three-view relative pose estimation. In particular, we propose GPH-HC based solvers to the 4-point and 6-line cases. Experiments on thousands of image pairs from publicly available datasets show that the proposed three-view 4-point solver is superior to the state-of-the-art two-view 6-point solver. One goal of future research is to use the technique proposed in [11] to improve the efficiency. We believe that the proposed method is promising and will be a good complement to existing methods to improve the accuracy and stability of the structure from motion systems. + +Acknowledgements. VL, KÅ received funding from ELLIIT. Kimia and Chien gratefully acknowledge the support of NSF award 1910530. + +# References + +[1] Paul Breiding and Sascha Timme. HomotopyContinuation.jl: A Package for Homotopy Continuation in Julia. In International Congress on Mathematical Software, pages 458-465. Springer, 2018. +[2] Chiang-Heng Chien, Hongyi Fan, Ahmad Abdelfattah, Elias Tsigaridas, Stanimire Tomov, and Benjamin Kimia. GPU-based homotopy continuation for minimal problems in computer vision. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 15765-15776, 2022. +[3] Chiang-Heng Chien, Hongyi Fan, Ahmad Abdelfattah, Elias Tsigaridas, Stanimire Tomov, and Benjamin Kimia. Parallel path tracking for homotopy continuation using GPU. In Proceedings of the International Symposium on Symbolic and Algebraic Computation, 2022. +[4] David A. Cox, John Little, and Donal O'shea. Using algebraic geometry. Springer Science & Business Media, 2006. +[5] Timothy Duff, Kathlen Kohn, Anton Leykin, and Tomas Pajdla. PLMP - Point-Line Minimal Problems in Complete Multi-View Visibility. In IEEE/CVF International Conference on Computer Vision (ICCV), 2019. +[6] Ricardo Fabbri, Timothy Duff, Hongyi Fan, Margaret H. Regan, David da C. de Pinho, Elias Tsigaridas, Charles W. Wampler, Jonathan D. Hauenstein, Peter J. Giblin, Benjamin Kimia, Anton Leykin, and Tomas Pajdla. Trifocal Relative Pose From Lines at Points. Trans. Pattern Analysis and Machine Intelligence (PAMI), 2022. +[7] Martin A Fischler and Robert C Bolles. Random sample consensus: a paradigm for model fitting with applications to image analysis and automated cartography. Communications of the ACM, 1981. +[8] Jonathan D Hauenstein and Margaret H Regan. Adaptive strategies for solving parameterized systems using homotopy continuation. Applied Mathematics and Computation, 332:19-34, 2018. +[9] Robert J. Holt and Arun N. Netravali. Motion and structure from line correspondences: Some further results. International Journal of Imaging Systems and Technology, 1994. +[10] Hongdong Li, Richard Hartley, and Jae-hak Kim. A linear approach to motion estimation using generalized camera models. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2008. +[11] Petr Hruby, Timothy Duff, Anton Leykin, and Tomas Pajdla. Learning to Solve Hard Minimal Problems. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2022. +[12] Zuzana Kukelova, Martin Bujnak, and Tomas Pajdla. Automatic generator of minimal problem solvers. In European Conference on Computer Vision (ECCV), 2008. +[13] Viktor Larsson, Kalle Åström, and Magnus Oskarsson. Efficient solvers for minimal problems by syzygy-based reduction. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2017. +[14] Viktor Larsson, Magnus Oskarsson, Kalle Åström, Alge Wallis, Zuzana Kukelova, and Tomas Pajdla. Beyond gröbner bases: Basis selection for minimal solvers. In + +IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2018. +[15] Gim Hee Lee, Marc Pollefeys, and Friedrich Fraundorfer. Relative Pose Estimation for a Multi-camera System with Known Vertical Direction. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2014. +[16] David G Lowe. Distinctive image features from scale-invariant keypoints. International Journal of Computer Vision (IJCV), 2004. +[17] Branislav Micusik and Tomas Pajdla. Autocalibration & 3d reconstruction with non-central catadioptric cameras. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2004. +[18] Alexander Morgan. Solving polynomial systems using continuation for engineering and scientific problems. SIAM, 2009. +[19] David Nister and Frederik Schaffalitzky. Four Points in Two or Three Calibrated Views: Theory and Practice. International Journal of Computer Vision, 2006. +[20] Robert Pless. Using many cameras as one. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2003. +[21] Long Quan, Bill Triggs, and Bernard Mourrain. Some Results on Minimal Euclidean Reconstruction from Four Points. Journal of Mathematical Imaging and Vision, 2006. +[22] Paul-Edouard Sarlin, Mihai Dusmanu, Johannes L. Schonberger, Pablo Speciale, Lukas Gruber, Viktor Larsson, Ondrej Miksik, and Marc Pollefeys. LaMAR: Benchmarking Localization and Mapping for Augmented Reality. In European Conference on Computer Vision (ECCV), 2022. +[23] Johannes L Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2016. +[24] Andrew J Sommese and Charles W Wampler. The Numerical solution of systems of polynomials arising in engineering and science. World Scientific, 2005. +[25] Henrik Stewenius, David Nister, Magnus Oskarsson, and Kalle Åström. Solutions to minimal generalized relative pose problems. In Workshop on omnidirectional vision, 2005. +[26] Peter Sturm. Multi-View Geometry for General Camera Models. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2005. \ No newline at end of file diff --git a/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/images.zip b/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..5d528e8ddceafc4d1fd33f689fb70e140727b275 --- /dev/null +++ b/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:512941a7af6442c0fc3272c93a46b3c79ba564cc6e5a6c233183f4c70a855157 +size 940161 diff --git a/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/layout.json b/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..e30f28cfbd38e53f1c60912731e005b5e6d86b6e --- /dev/null +++ b/2023/Minimal Solutions to Generalized Three-View Relative Pose Problem/layout.json @@ -0,0 +1,9804 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 84, + 103, + 509, + 119 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 84, + 103, + 509, + 119 + ], + "spans": [ + { + "bbox": [ + 84, + 103, + 509, + 119 + ], + "type": "text", + "content": "Minimal Solutions to Generalized Three-View Relative Pose Problem" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "spans": [ + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "text", + "content": "Yaqing Ding" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "inline_equation", + "content": "^{1\\dagger}" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "text", + "content": ", Chiang-Heng Chien" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "inline_equation", + "content": "^{2\\dagger}" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "text", + "content": ", Viktor Larsson" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "text", + "content": ", Karl Åström" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "text", + "content": ", Benjamin Kimia" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "text", + "content": "Centre for Mathematical Sciences, Lund University \n" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 83, + 142, + 511, + 186 + ], + "type": "text", + "content": "School of Engineering, Brown University" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 224, + 192, + 238 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 224, + 192, + 238 + ], + "spans": [ + { + "bbox": [ + 143, + 224, + 192, + 238 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 45, + 251, + 290, + 407 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 251, + 290, + 407 + ], + "spans": [ + { + "bbox": [ + 45, + 251, + 290, + 407 + ], + "type": "text", + "content": "For a generalized (or non-central) camera model, the minimal problem for two views of six points has efficient solvers. However, minimal problems of three views with four points and three views of six lines have not yet been explored and solved, despite the efforts from the computer vision community. This paper develops the formulations of these two minimal problems and shows how state-of-the-art GPU implementations of Homotopy Continuation solver can be used effectively. The proposed methods are evaluated on both synthetic and real datasets, demonstrating that they are fast, accurate and that they improve on structure from motion estimations, when employed in an hypothesis and test setting." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 431, + 128, + 443 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 431, + 128, + 443 + ], + "spans": [ + { + "bbox": [ + 47, + 431, + 128, + 443 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 45, + 453, + 288, + 693 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 45, + 453, + 288, + 693 + ], + "spans": [ + { + "bbox": [ + 45, + 453, + 288, + 693 + ], + "type": "text", + "content": "In both the central and the non-central camera models, an image point is in correspondence to a ray of a 3D point that projects to that image point. In the central camera model, each such ray goes through a common point, i.e., the camera centre, whereas in the non-central camera model, two such rays do not always intersect. One example of a non-central camera is the catadioptric camera, where one or more lenses and/or mirrors are combined in an optical system, [17]. Another example is a rig of multiple cameras, [20]. A typical use-case is a car or drone equipped with several cameras. Here it is possible to use all of the cameras as one generalized sensor. Generalized cameras offer several advantages over the standard pinhole camera for relative pose estimation. As shown in previous works [20, 25, 10, 15], structure from motion estimation with a generalized camera also gives the scale of the translation as well as the scale of the 3D model. In addition, since the system consists of multiple cameras, it is possible to configure the location of each camera so that a maximal field-of-view can be achieved to avoid blind spots. This, in turn, enables more robust image" + } + ] + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 307, + 222, + 545, + 365 + ], + "blocks": [ + { + "bbox": [ + 307, + 222, + 545, + 365 + ], + "lines": [ + { + "bbox": [ + 307, + 222, + 545, + 365 + ], + "spans": [ + { + "bbox": [ + 307, + 222, + 545, + 365 + ], + "type": "image", + "image_path": "967268b135f7209fea3d4f2080b544ce85b523595ce129f0a96e4eb22b2c1f03.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 306, + 368, + 546, + 391 + ], + "lines": [ + { + "bbox": [ + 306, + 368, + 546, + 391 + ], + "spans": [ + { + "bbox": [ + 306, + 368, + 546, + 391 + ], + "type": "text", + "content": "Figure 1. An example of a multi-camera system with four standard pinhole cameras mounted on a car." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 413, + 546, + 460 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 413, + 546, + 460 + ], + "spans": [ + { + "bbox": [ + 304, + 413, + 546, + 460 + ], + "type": "text", + "content": "feature detection and matching, which is a crucial procedure in relative pose estimation. Fig. 1 shows an example of a multi-camera system consisting of four pinhole cameras mounted on a car for relative pose estimation." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 462, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 462, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 462, + 547, + 715 + ], + "type": "text", + "content": "Unlike the standard pinhole camera, the light rays from a generalized camera do not intersect at a single center of projection. This property makes it non-trivial to estimate the relative pose using a generalized camera. Pless [20] first formulated the light rays in a generalized camera as Plücker vectors and defined the generalized essential matrix. Based on the work of Pless, several solutions to the two-view generalized relative pose estimation have been proposed [26, 10, 25]. Among these solutions, the minimal solver with up to 64 solutions was proposed in [25]. This solver only needs 6 point correspondences which can significantly reduce the number of RANSAC [7] iterations than other solvers. Although the solvers to the two-view generalized relative pose problem are already mature, there are no solutions to the three-view case as the generalized three-view relative pose problem is extremely difficult to be formulated and solved. In general, three-view relative pose estimation needs fewer point correspondence and suffers from fewer degenerate cases than the two-view case. Moreover, three-view relative pose can be estimated only using the line correspondences. Hence, it has a great po" + } + ] + } + ], + "index": 11 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 62, + 703, + 132, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 62, + 703, + 132, + 712 + ], + "spans": [ + { + "bbox": [ + 62, + 703, + 132, + 712 + ], + "type": "inline_equation", + "content": "\\dagger" + }, + { + "bbox": [ + 62, + 703, + 132, + 712 + ], + "type": "text", + "content": " Equal contribution." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8156" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 62, + 70, + 271, + 191 + ], + "blocks": [ + { + "bbox": [ + 62, + 70, + 271, + 191 + ], + "lines": [ + { + "bbox": [ + 62, + 70, + 271, + 191 + ], + "spans": [ + { + "bbox": [ + 62, + 70, + 271, + 191 + ], + "type": "table", + "html": "
Point •Line →Quiver •→No. of Solutions
4-point400583
6-line060600
3-quiver0031008
2P3L230920
2P1L1Q2111472
4L1Q0411976
2L2Q0222240
", + "image_path": "8947957ffb4a99c4e958e2cd5043947ad7894cd60490730ecddafadf3d7f9e17.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 198, + 288, + 254 + ], + "lines": [ + { + "bbox": [ + 46, + 198, + 288, + 254 + ], + "spans": [ + { + "bbox": [ + 46, + 198, + 288, + 254 + ], + "type": "text", + "content": "Table 1. Possible cases and number of solutions for the generalized three-view relative pose problem. Each row shows the number of necessary features and the number of solutions. We mainly focus on the first two cases in this paper since they are more practical and relevant." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 262, + 287, + 285 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 262, + 287, + 285 + ], + "spans": [ + { + "bbox": [ + 46, + 262, + 287, + 285 + ], + "type": "text", + "content": "tential and can provide new ways to solve the relative pose problem." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 288, + 287, + 455 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 288, + 287, + 455 + ], + "spans": [ + { + "bbox": [ + 46, + 288, + 287, + 455 + ], + "type": "text", + "content": "The generalized three-view relative pose problem has 12 degrees of freedom (6 for the two rotations and 6 for the two translations). It is well known that the most commonly used features for relative pose estimation are points, lines and quivers, where a quiver consists of one point with tangent direction (or one point with one line passing through this point). According to the analyses in [5, 6], point, line and quiver in three views can provide 3,2 and 4 constraints, respectively. In Table 1, we show that there are 7 possible minimal cases for generalized three-view relative pose estimation using the combination of the three features. We only assume that there is one line passing through the point, there will be much more cases if there are several lines passing through one point." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 457, + 287, + 518 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 457, + 287, + 518 + ], + "spans": [ + { + "bbox": [ + 46, + 457, + 287, + 518 + ], + "type": "text", + "content": "In this paper, to estimate the generalized three-view relative pose, we focus on the first two cases in Table 1. We show detailed discussions on the formulations and the number of solutions for each case. The main contributions of this paper include:" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 58, + 525, + 287, + 714 + ], + "type": "list", + "angle": 0, + "index": 8, + "blocks": [ + { + "bbox": [ + 58, + 525, + 287, + 585 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 525, + 287, + 585 + ], + "spans": [ + { + "bbox": [ + 58, + 525, + 287, + 585 + ], + "type": "text", + "content": "- We solve the generalized three-view relative pose problem using 4 points or 6 lines. Specifically, detailed problem formulation for the two cases are given, which are then converted into solving a squared system of polynomials." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 58, + 595, + 287, + 643 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 595, + 287, + 643 + ], + "spans": [ + { + "bbox": [ + 58, + 595, + 287, + 643 + ], + "type": "text", + "content": "- This allows us to develop a solver using HC (homotopy continuation) based on the state-of-the-art GPU-HC solver [2, 3]. This significantly improves the efficiency over the existing modern HC software." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 58, + 654, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 654, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 58, + 654, + 287, + 714 + ], + "type": "text", + "content": "- In extensive synthetic and real experiments we show an improvement of accuracy over the state-of-the-art two-view 6-point solver. The proposed 4-point solver is able to deal with semi-pure translation, which is degenerated for the two-view case." + } + ] + } + ], + "index": 7 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 71, + 392, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 71, + 392, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 71, + 392, + 84 + ], + "type": "text", + "content": "2. Related Work" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 93, + 545, + 320 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 93, + 545, + 320 + ], + "spans": [ + { + "bbox": [ + 304, + 93, + 545, + 320 + ], + "type": "text", + "content": "Three-view Relative Pose. Estimating the calibrated three-view relative pose from standard pinhole cameras has been well studied in the literature. In general, this problem has 11 degrees of freedom (DOF), and can be solved using 4 points [19, 21] or 6 lines [9]. Note that, both 4 points and 6 lines are over-determined for standard pinhole cameras, which makes it difficult to derive stable solvers. The only available solver for the 4-point problem was shown in [11], where the authors added an extra parameter to solve a relaxed version of the problem. To the best of our knowledge, there are no publicly available solvers for the 6-line problem. It was shown in [9] that there might be up to 600 solutions to three-view relative pose with 6 lines using pinhole cameras. While the problem of estimating the three-view relative pose from standard pinhole cameras has received a lot of attention, this does not hold for the generalized three-view relative pose problem. There is only a discussion on the possible number of solutions using 4 points in three generalized views [25]." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 323, + 546, + 634 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 323, + 546, + 634 + ], + "spans": [ + { + "bbox": [ + 304, + 323, + 546, + 634 + ], + "type": "text", + "content": "Solving Polynomials. Most of the minimal problems in computer vision can be transformed into solving a system of polynomial equations. A straightforward way of solving a polynomial system is to use the Gröbner basis method [4] and generate a specific solver using an automatic generator, e.g., [12, 13, 14]. The Gröbner basis method and related automatic generators have been successfully used in many computer vision problems [14], showing promising results in terms of stability and efficiency. However, it's difficult to find a stable solution for large scale problems using the Gröbner basis technique, since we need to apply Gauss-Jordan elimination and eigenvalue decomposition to large size of matrices. Alternatively, homotopy continuation (HC) [24, 8], one of the promising numerical solver for polynomial equations, is able to handle systems that are out of the reach of the Gröbner basis methods. However, HC algorithms are known to be slow, impractical for many multiview geometry problems when a RANSAC loop is involved, e.g. trifocal relative pose estimation requires over 600 (ms) per correspondence in [6]. This issue has been tackled by GPU-HC [2, 3] where the design of the GPU implementation accelerate the speed in orders of magnitude, giving efficient and accurate estimations for many minimal problems. As there is no paper using GPU-HC to solve minimal problems in practice, this paper stands out as the first approach to leverage it as our solvers." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 645, + 420, + 658 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 645, + 420, + 658 + ], + "spans": [ + { + "bbox": [ + 306, + 645, + 420, + 658 + ], + "type": "text", + "content": "3. Problem Statement" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 665, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 715 + ], + "type": "text", + "content": "As SO(3) is three-dimensional, and we set the first generalized camera to " + }, + { + "bbox": [ + 304, + 665, + 545, + 715 + ], + "type": "inline_equation", + "content": "[1\\mid 0]" + }, + { + "bbox": [ + 304, + 665, + 545, + 715 + ], + "type": "text", + "content": ", the parameter space of camera configurations for " + }, + { + "bbox": [ + 304, + 665, + 545, + 715 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 304, + 665, + 545, + 715 + ], + "type": "text", + "content": "-view case has dimension " + }, + { + "bbox": [ + 304, + 665, + 545, + 715 + ], + "type": "inline_equation", + "content": "6n - 6" + }, + { + "bbox": [ + 304, + 665, + 545, + 715 + ], + "type": "text", + "content": ". Since one point correspondence in three views gives three constraints," + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8157" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 49, + 58, + 287, + 185 + ], + "blocks": [ + { + "bbox": [ + 49, + 58, + 287, + 185 + ], + "lines": [ + { + "bbox": [ + 49, + 58, + 287, + 185 + ], + "spans": [ + { + "bbox": [ + 49, + 58, + 287, + 185 + ], + "type": "image", + "image_path": "8bd0ca09d1ec8b29107a81e2ba5859e8123ff80f64bce0362e07f8a31eb64fe9.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 185, + 287, + 218 + ], + "lines": [ + { + "bbox": [ + 46, + 185, + 287, + 218 + ], + "spans": [ + { + "bbox": [ + 46, + 185, + 287, + 218 + ], + "type": "text", + "content": "Figure 2. The minimal problem of 4 points seen in three generalized cameras. In this example the generalized cameras are visualized as multi-camera systems." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 239, + 287, + 275 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 239, + 287, + 275 + ], + "spans": [ + { + "bbox": [ + 46, + 239, + 287, + 275 + ], + "type": "text", + "content": "and one line correspondence in three views gives two constraints, we can find that 4 points and 6 lines in three views are two minimal cases." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 285, + 149, + 298 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 285, + 149, + 298 + ], + "spans": [ + { + "bbox": [ + 47, + 285, + 149, + 298 + ], + "type": "text", + "content": "3.1. The 4-point Case" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "spans": [ + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "type": "text", + "content": "Assuming that four points " + }, + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "type": "inline_equation", + "content": "\\mathbf{X}_1, \\mathbf{X}_2, \\mathbf{X}_3, \\mathbf{X}_4" + }, + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "type": "text", + "content": " in the 3D space are observed by three generalized cameras (Figure 2). Note that, the four points " + }, + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{X}_1, \\mathbf{X}_2, \\mathbf{X}_3, \\mathbf{X}_4\\}" + }, + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "type": "text", + "content": " can't be viewed from a single pinhole camera, i.e., the points need to be sampled from at least two cameras. Otherwise, the problem will be degenerated into the trifocal relative pose from a standard pinhole camera. The image points of the four 3D points in each view can be written as " + }, + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "type": "inline_equation", + "content": "\\mathbf{x}_{1i}, \\mathbf{x}_{2i}, \\mathbf{x}_{3i}, \\mathbf{x}_{4i}, i \\in \\{1, 2, 3\\}" + }, + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "type": "text", + "content": ". On the other hand, the rotation matrices and translation vectors that align the image points with the world coordinate are defined as " + }, + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{A}_{ki}, \\boldsymbol{\\tau}_{ki}\\}" + }, + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "type": "text", + "content": ". We formulate the depths of the image points in each generalized view as " + }, + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "type": "inline_equation", + "content": "\\lambda_{1i}, \\lambda_{2i}, \\lambda_{3i}, \\lambda_{4i}, i \\in \\{1, 2, 3\\}" + }, + { + "bbox": [ + 46, + 304, + 289, + 483 + ], + "type": "text", + "content": ". Due to the rigid motion, the distance between any two points in each view should be the same. Hence, we have" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 495, + 294, + 552 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 495, + 294, + 552 + ], + "spans": [ + { + "bbox": [ + 47, + 495, + 294, + 552 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\left\\| \\lambda_ {1 1} \\mathbf {A} _ {1 1} \\mathbf {x} _ {1 1} + \\boldsymbol {\\tau} _ {1 1} - \\lambda_ {2 1} \\mathbf {A} _ {2 1} \\mathbf {x} _ {2 1} - \\boldsymbol {\\tau} _ {2 1} \\right\\| ^ {2} \\\\ = \\left\\| \\lambda_ {1 2} \\mathbf {A} _ {1 2} \\mathbf {x} _ {1 2} + \\boldsymbol {\\tau} _ {1 2} - \\lambda_ {2 2} \\mathbf {A} _ {2 2} \\mathbf {x} _ {2 2} - \\boldsymbol {\\tau} _ {2 2} \\right\\| ^ {2} \\tag {1} \\\\ \\end{array}", + "image_path": "058d88e3e0573ca75f779f108d13bbdcc6b06b7861225a5f0d8e59826e5930bb.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 555, + 294, + 586 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 555, + 294, + 586 + ], + "spans": [ + { + "bbox": [ + 47, + 555, + 294, + 586 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\left\\| \\lambda_ {3 1} \\mathbf {A} _ {3 1} \\mathbf {x} _ {3 1} + \\boldsymbol {\\tau} _ {3 1} - \\lambda_ {4 1} \\mathbf {A} _ {4 1} \\mathbf {x} _ {4 1} - \\boldsymbol {\\tau} _ {4 1} \\right\\| ^ {2} \\\\ = \\left\\| \\lambda_ {4 3} \\mathbf {A} _ {4 3} \\mathbf {x} _ {4 3} + \\boldsymbol {\\tau} _ {4 3} - \\lambda_ {4 4} \\mathbf {A} _ {4 4} \\mathbf {x} _ {4 4} - \\boldsymbol {\\tau} _ {4 4} \\right\\| ^ {2} \\\\ \\end{array}", + "image_path": "99d4109ce300d61ba67cd780a170de1592269a2580d2859e49a2bde9ce17a928.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 595, + 287, + 642 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 595, + 287, + 642 + ], + "spans": [ + { + "bbox": [ + 47, + 595, + 287, + 642 + ], + "type": "text", + "content": "In this case, we obtain 12 polynomials in 12 unknowns " + }, + { + "bbox": [ + 47, + 595, + 287, + 642 + ], + "type": "inline_equation", + "content": "\\{\\lambda_{1i},\\lambda_{2i},\\lambda_{3i},\\lambda_{4i}\\}" + }, + { + "bbox": [ + 47, + 595, + 287, + 642 + ], + "type": "text", + "content": ". Based on [1], we find that there are up to 583 solutions. Once the depth parameters are computed, we let" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 116, + 646, + 287, + 658 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 116, + 646, + 287, + 658 + ], + "spans": [ + { + "bbox": [ + 116, + 646, + 287, + 658 + ], + "type": "interline_equation", + "content": "\\mathbf {X} _ {k i} = \\lambda_ {k i} \\mathbf {A} _ {k i} \\mathbf {x} _ {k i} + \\boldsymbol {\\tau} _ {k}, \\tag {2}", + "image_path": "767445b8cb86fcffdb93949dd6993d04aaa7a24c353ac57ffbb07c1a61ffd95b.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 665, + 287, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 665, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 47, + 665, + 287, + 689 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 665, + 287, + 689 + ], + "type": "inline_equation", + "content": "k \\in \\{1, 2, 3, 4\\}" + }, + { + "bbox": [ + 47, + 665, + 287, + 689 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 665, + 287, + 689 + ], + "type": "inline_equation", + "content": "i \\in \\{1, 2, 3\\}" + }, + { + "bbox": [ + 47, + 665, + 287, + 689 + ], + "type": "text", + "content": ". We have the following constraints" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 122, + 701, + 287, + 713 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 122, + 701, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 122, + 701, + 287, + 713 + ], + "type": "interline_equation", + "content": "\\mathbf {X} _ {k 2} = \\mathbf {R} _ {2} \\mathbf {X} _ {k 1} + \\mathbf {t} _ {2}. \\tag {3}", + "image_path": "d27d970f86dc149a95b69451693bb333385ac93a6ca093c0150aef073a09f596.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 306, + 72, + 512, + 84 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 512, + 84 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 512, + 84 + ], + "type": "text", + "content": "By eliminating the translation parameters, we have" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 329, + 91, + 545, + 105 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 329, + 91, + 545, + 105 + ], + "spans": [ + { + "bbox": [ + 329, + 91, + 545, + 105 + ], + "type": "interline_equation", + "content": "\\mathbf {X} _ {k 2} - \\mathbf {X} _ {1 2} = \\mathbf {R} _ {2} \\left(\\mathbf {X} _ {k 1} - \\mathbf {X} _ {1 1}\\right), k \\in \\{2, 3, 4 \\}. \\tag {4}", + "image_path": "551171c94faa02094f6bd46e221ae680f589c3b4188e1a668bd5cb679288166c.jpg" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 306, + 112, + 496, + 125 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 112, + 496, + 125 + ], + "spans": [ + { + "bbox": [ + 306, + 112, + 496, + 125 + ], + "type": "text", + "content": "Hence, the rotation matrix " + }, + { + "bbox": [ + 306, + 112, + 496, + 125 + ], + "type": "inline_equation", + "content": "\\mathbf{R}_2" + }, + { + "bbox": [ + 306, + 112, + 496, + 125 + ], + "type": "text", + "content": " can be found by" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 332, + 130, + 397, + 144 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 332, + 130, + 397, + 144 + ], + "spans": [ + { + "bbox": [ + 332, + 130, + 397, + 144 + ], + "type": "interline_equation", + "content": "\\mathbf {R} _ {2} = \\mathbf {B} _ {2} \\mathbf {B} _ {1} ^ {- 1},", + "image_path": "01e0cef913004d035f82ae3c23297030793637eba90d8c235b6018646a4b902b.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 332, + 146, + 545, + 159 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 332, + 146, + 545, + 159 + ], + "spans": [ + { + "bbox": [ + 332, + 146, + 545, + 159 + ], + "type": "interline_equation", + "content": "\\mathbf {B} _ {2} = \\left[ \\mathbf {X} _ {2 2} - \\mathbf {X} _ {1 2}, \\mathbf {X} _ {3 2} - \\mathbf {X} _ {1 2}, \\mathbf {X} _ {4 2} - \\mathbf {X} _ {1 2} \\right], \\tag {5}", + "image_path": "4b3a1e17a7378afb26cffbf7c27bfb61a6983047da9b078fffd71bd6a3078b27.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 332, + 161, + 518, + 175 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 332, + 161, + 518, + 175 + ], + "spans": [ + { + "bbox": [ + 332, + 161, + 518, + 175 + ], + "type": "interline_equation", + "content": "\\mathbf {B} _ {1} = \\left[ \\mathbf {X} _ {2 1} - \\mathbf {X} _ {1 1}, \\mathbf {X} _ {3 1} - \\mathbf {X} _ {1 1}, \\mathbf {X} _ {4 1} - \\mathbf {X} _ {1 1} \\right].", + "image_path": "73d844c7f455e4685d29f06947139c12b76e10bf90fdf5b7385464b90660c4b3.jpg" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 182, + 545, + 205 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 182, + 545, + 205 + ], + "spans": [ + { + "bbox": [ + 306, + 182, + 545, + 205 + ], + "type": "text", + "content": "Then the translation can be computed using (3). Similarly, we can obtain " + }, + { + "bbox": [ + 306, + 182, + 545, + 205 + ], + "type": "inline_equation", + "content": "\\mathbf{R}_3" + }, + { + "bbox": [ + 306, + 182, + 545, + 205 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 306, + 182, + 545, + 205 + ], + "type": "inline_equation", + "content": "\\mathbf{t}_3" + }, + { + "bbox": [ + 306, + 182, + 545, + 205 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 212, + 401, + 223 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 212, + 401, + 223 + ], + "spans": [ + { + "bbox": [ + 306, + 212, + 401, + 223 + ], + "type": "text", + "content": "3.2. The 6-line Case" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 305, + 230, + 545, + 312 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 230, + 545, + 312 + ], + "spans": [ + { + "bbox": [ + 305, + 230, + 545, + 312 + ], + "type": "text", + "content": "Assuming that six lines " + }, + { + "bbox": [ + 305, + 230, + 545, + 312 + ], + "type": "inline_equation", + "content": "\\mathbf{L}_1, \\mathbf{L}_2, \\dots, \\mathbf{L}_6" + }, + { + "bbox": [ + 305, + 230, + 545, + 312 + ], + "type": "text", + "content": " in the 3D space are observed by three generalized cameras. The projections of the lines in each view can be written as " + }, + { + "bbox": [ + 305, + 230, + 545, + 312 + ], + "type": "inline_equation", + "content": "l_{1i}, l_{2i}, \\dots, l_{6i}, i \\in \\{1, 2, 3\\}" + }, + { + "bbox": [ + 305, + 230, + 545, + 312 + ], + "type": "text", + "content": ". The line and the camera center define a plane which passes through the origin of the local camera coordinate. In this case, the plane in each camera coordinate can be formulated as" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 395, + 314, + 545, + 327 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 395, + 314, + 545, + 327 + ], + "spans": [ + { + "bbox": [ + 395, + 314, + 545, + 327 + ], + "type": "interline_equation", + "content": "\\boldsymbol {\\pi} _ {k i} = \\left[ \\boldsymbol {l} _ {k i}; 0 \\right]. \\tag {6}", + "image_path": "6fd9f6774d6d42dd6ac2d927411f4447650d538f37f3fa5fde6fb96a8ee3a97d.jpg" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 305, + 331, + 545, + 354 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 331, + 545, + 354 + ], + "spans": [ + { + "bbox": [ + 305, + 331, + 545, + 354 + ], + "type": "text", + "content": "In addition, we let the " + }, + { + "bbox": [ + 305, + 331, + 545, + 354 + ], + "type": "inline_equation", + "content": "4 \\times 4" + }, + { + "bbox": [ + 305, + 331, + 545, + 354 + ], + "type": "text", + "content": " transformation matrices that align the planes with the world coordinate as" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 372, + 361, + 545, + 388 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 372, + 361, + 545, + 388 + ], + "spans": [ + { + "bbox": [ + 372, + 361, + 545, + 388 + ], + "type": "interline_equation", + "content": "\\mathbf {C} _ {k i} = \\left[ \\begin{array}{c c} \\mathbf {A} _ {k i} & \\boldsymbol {\\tau} _ {k i} \\\\ \\mathbf {0} & 1 \\end{array} \\right]. \\tag {7}", + "image_path": "8ec52602a84dbb5127e3da29b487fefa17272b0a74a588cde058ac8898887e24.jpg" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 305, + 393, + 545, + 430 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 393, + 545, + 430 + ], + "spans": [ + { + "bbox": [ + 305, + 393, + 545, + 430 + ], + "type": "text", + "content": "The planes in three views which are defined by one 3D line should intersect at this line, in this case, we can obtain the following constraints" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 318, + 435, + 545, + 464 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 318, + 435, + 545, + 464 + ], + "spans": [ + { + "bbox": [ + 318, + 435, + 545, + 464 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\operatorname {r a n k} \\left[ \\mathbf {P} _ {1} ^ {\\top} \\mathbf {C} _ {k} ^ {\\top} \\boldsymbol {\\pi} _ {k 1} \\mid \\mathbf {P} _ {2} ^ {\\top} \\mathbf {C} _ {k} ^ {\\top} \\boldsymbol {\\pi} _ {k 2} \\mid \\mathbf {P} _ {3} ^ {\\top} \\mathbf {C} _ {k} ^ {\\top} \\boldsymbol {\\pi} _ {k 3} \\right] \\leq 2, \\tag {8} \\\\ k \\in \\{1, 2, 3, 4, 5, 6 \\}, \\\\ \\end{array}", + "image_path": "b89490072f99fb80b007bee0dd7d1c3b0667e50a72b0ecda57635877504b2d39.jpg" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 306, + 472, + 428, + 483 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 472, + 428, + 483 + ], + "spans": [ + { + "bbox": [ + 306, + 472, + 428, + 483 + ], + "type": "text", + "content": "where matrix " + }, + { + "bbox": [ + 306, + 472, + 428, + 483 + ], + "type": "inline_equation", + "content": "\\mathbf{P}_i" + }, + { + "bbox": [ + 306, + 472, + 428, + 483 + ], + "type": "text", + "content": " is defined as" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 352, + 490, + 545, + 516 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 352, + 490, + 545, + 516 + ], + "spans": [ + { + "bbox": [ + 352, + 490, + 545, + 516 + ], + "type": "interline_equation", + "content": "\\mathbf {P} _ {i} = \\left[ \\begin{array}{c c} \\mathbf {R} _ {i} & \\boldsymbol {t} _ {i} \\\\ \\mathbf {0} & 1 \\end{array} \\right], i \\in \\{1, 2, 3 \\}. \\tag {9}", + "image_path": "f98ecfc90f15293475dbdfd70773a2912103e22d9427e0b84781ee61e668b325.jpg" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 305, + 523, + 545, + 571 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 523, + 545, + 571 + ], + "spans": [ + { + "bbox": [ + 305, + 523, + 545, + 571 + ], + "type": "text", + "content": "Based on (9), we can obtain " + }, + { + "bbox": [ + 305, + 523, + 545, + 571 + ], + "type": "inline_equation", + "content": "6 * \\mathrm{C}_3^4 = 24" + }, + { + "bbox": [ + 305, + 523, + 545, + 571 + ], + "type": "text", + "content": " polynomials in the rotation and translation parameters. If we consider the constraints that only contain the rotation components, we have 6 constraints in the rotation parameters" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 327, + 577, + 545, + 607 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 577, + 545, + 607 + ], + "spans": [ + { + "bbox": [ + 327, + 577, + 545, + 607 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\det \\left[ \\mathbf {A} _ {k 1} ^ {\\top} l _ {k 1} \\mid \\mathbf {R} _ {2} ^ {\\top} \\mathbf {A} _ {k 2} ^ {\\top} l _ {k 2} \\mid \\mathbf {R} _ {3} ^ {\\top} \\mathbf {A} _ {k 3} ^ {\\top} l _ {k 3} \\right] = 0, \\tag {10} \\\\ k \\in \\{1, 2, 3, 4, 5, 6 \\}. \\\\ \\end{array}", + "image_path": "5d9ce2a811a7f9cd696a3f47edc04236d3ad71a0dd3ac267782687b891f0186b.jpg" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 305, + 614, + 545, + 636 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 614, + 545, + 636 + ], + "spans": [ + { + "bbox": [ + 305, + 614, + 545, + 636 + ], + "type": "text", + "content": "In order to find the motion parameters, we introduce two formulations for the rotation matrix." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 305, + 639, + 545, + 674 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 639, + 545, + 674 + ], + "spans": [ + { + "bbox": [ + 305, + 639, + 545, + 674 + ], + "type": "text", + "content": "Cayley parameterization. The major advantage lies in this formulation is that there remain only three variables for each rotation matrix:" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 306, + 680, + 541, + 717 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 680, + 541, + 717 + ], + "spans": [ + { + "bbox": [ + 306, + 680, + 541, + 717 + ], + "type": "interline_equation", + "content": "\\mathbf {R} _ {2} = \\frac {1}{\\kappa_ {2}} \\left[ \\begin{array}{c c c} 1 + q _ {1} ^ {2} - q _ {2} ^ {2} - q _ {3} ^ {2} & 2 (q _ {1} q _ {2} - q _ {3}) & 2 (q _ {1} q _ {3} + q _ {2}) \\\\ 2 (q _ {1} q _ {2} + q _ {3}) & 1 - q _ {1} ^ {2} + q _ {2} ^ {2} - q _ {3} ^ {2} & 2 (q _ {2} q _ {3} - q _ {1}) \\\\ 2 (q _ {1} q _ {3} - q _ {2}) & 2 (q _ {2} q _ {3} + q _ {1}) & 1 - q _ {1} ^ {2} - q _ {2} ^ {2} + q _ {3} ^ {2} \\end{array} \\right]", + "image_path": "af52c0f4aa929d3b22f75a7a005285492ee3266a13571a841cec1d78d88d5afd.jpg" + } + ] + } + ], + "index": 31 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "8158" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 69, + 284, + 109 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 69, + 284, + 109 + ], + "spans": [ + { + "bbox": [ + 47, + 69, + 284, + 109 + ], + "type": "interline_equation", + "content": "\\mathbf {R} _ {3} = \\frac {1}{\\kappa_ {3}} \\left[ \\begin{array}{c c c} 1 + q _ {4} ^ {2} - q _ {5} ^ {2} - q _ {6} ^ {2} & 2 (q _ {4} q _ {5} - q _ {6}) & 2 (q _ {4} q _ {6} + q _ {5}) \\\\ 2 (q _ {4} q _ {5} + q _ {6}) & 1 - q _ {4} ^ {2} + q _ {5} ^ {2} - q _ {6} ^ {2} & 2 (q _ {5} q _ {6} - q _ {4}) \\\\ 2 (q _ {4} q _ {6} - q _ {5}) & 2 (q _ {5} q _ {6} + q _ {4}) & 1 - q _ {4} ^ {2} - q _ {5} ^ {2} + q _ {6} ^ {2} \\end{array} \\right],", + "image_path": "3bfa1e65fea71334970ccf0420f37ae8052fc6e54767f4aff15703b255f1057b.jpg" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "spans": [ + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "inline_equation", + "content": "\\kappa_{2} = 1 + q_{1}^{2} + q_{2}^{2} + q_{3}^{2}" + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "inline_equation", + "content": "\\kappa_{3} = 1 + q_{4}^{2} + q_{5}^{2} + q_{6}^{2}" + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "text", + "content": ", note that this formulation is unstable in case of Cayley degenerate rotations (" + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "inline_equation", + "content": "\\kappa_{2}, \\kappa_{3} = 0" + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "text", + "content": "). However, the probability for the degenerate case is quite low in practice, and this formulation has been successfully used in many computer vision problems [13]. Since the constraints (10) are homogenous in the rotation matrices, the scale factors " + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "inline_equation", + "content": "\\kappa_{2}, \\kappa_{3}" + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "text", + "content": " can be omitted. In this case, we can obtain 6 quartic polynomials in 6 unknowns " + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "inline_equation", + "content": "\\{q_{1}, q_{2}, \\dots, q_{6}\\}" + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "text", + "content": ". The monodromy solver in [1] shows that there are up to 600 solutions. Once the rotation parameters are computed, we need to substitute them into (8) and obtain six linear equations in the translation parameters. The translation " + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "inline_equation", + "content": "\\mathbf{t}_{2}" + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "inline_equation", + "content": "\\mathbf{t}_{3}" + }, + { + "bbox": [ + 46, + 115, + 287, + 272 + ], + "type": "text", + "content": " can be uniquely obtained." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 274, + 287, + 322 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 274, + 287, + 322 + ], + "spans": [ + { + "bbox": [ + 46, + 274, + 287, + 322 + ], + "type": "text", + "content": "Homogeneous rotation matrix. On the other hand, since constraints (8) are invariant to the scale of the rotation matrices, we can use 8 parameters to formulate the rotation up to a scale factor (assuming the first element to be 1)" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 56, + 329, + 257, + 369 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 56, + 329, + 257, + 369 + ], + "spans": [ + { + "bbox": [ + 56, + 329, + 257, + 369 + ], + "type": "interline_equation", + "content": "\\mathbf {R} _ {2} = \\left[ \\begin{array}{c c c} 1 & r _ {2} & r _ {3} \\\\ r _ {4} & r _ {5} & r _ {6} \\\\ r _ {7} & r _ {8} & r _ {9} \\end{array} \\right], \\mathbf {R} _ {3} = \\left[ \\begin{array}{c c c} 1 & r _ {1 1} & r _ {1 2} \\\\ r _ {1 3} & r _ {1 4} & r _ {1 5} \\\\ r _ {1 6} & r _ {1 7} & r _ {1 8} \\end{array} \\right].", + "image_path": "1e663bd22f5e3bed4bd145417828b1bd38eacd69cf84fc8b2970da5a0646f377.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 376, + 287, + 399 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 376, + 287, + 399 + ], + "spans": [ + { + "bbox": [ + 46, + 376, + 287, + 399 + ], + "type": "text", + "content": "The elements " + }, + { + "bbox": [ + 46, + 376, + 287, + 399 + ], + "type": "inline_equation", + "content": "\\{r_2, r_2, \\ldots, r_9\\}" + }, + { + "bbox": [ + 46, + 376, + 287, + 399 + ], + "type": "text", + "content": " should satisfy the following constraints" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 64, + 407, + 253, + 451 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 64, + 407, + 253, + 451 + ], + "spans": [ + { + "bbox": [ + 64, + 407, + 253, + 451 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} r _ {2} r _ {8} + r _ {3} r _ {9} + r _ {7} = 0, r _ {2} r _ {5} + r _ {3} r _ {6} + r _ {4} = 0, \\\\ r _ {4} r _ {6} + r _ {7} r _ {9} + r _ {3} = 0, r _ {4} r _ {5} + r _ {7} r _ {8} + r _ {2} = 0, \\\\ r _ {5} ^ {2} + r _ {6} ^ {2} - r _ {7} ^ {2} - 1 = 0. \\\\ \\end{array}", + "image_path": "c8bb754db20396523370254ccc21cca7e7393a0098303356f8362f0eed2017a5.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 458, + 287, + 579 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 458, + 287, + 579 + ], + "spans": [ + { + "bbox": [ + 46, + 458, + 287, + 579 + ], + "type": "text", + "content": "In this case, we can obtain 16 quadratic polynomials in 16 unknowns " + }, + { + "bbox": [ + 46, + 458, + 287, + 579 + ], + "type": "inline_equation", + "content": "\\{r_2,r_3,\\dots,r_{18}\\}" + }, + { + "bbox": [ + 46, + 458, + 287, + 579 + ], + "type": "text", + "content": ". Similar to the Cayley parameterization, this formulation is unstable in case of degenerate rotations " + }, + { + "bbox": [ + 46, + 458, + 287, + 579 + ], + "type": "inline_equation", + "content": "(r_1,r_{10} = 0)" + }, + { + "bbox": [ + 46, + 458, + 287, + 579 + ], + "type": "text", + "content": ". Although such degenerate cases can be avoided by using unit quaternion formulation, it will result in more parameters than the Cayley parameterization and the system of polynomials has 2-fold symmetry. In order to derive more efficient solvers, we only discuss Cayley parameterization and homogeneous rotation matrix formulation in this paper." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 580, + 287, + 652 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 580, + 287, + 652 + ], + "spans": [ + { + "bbox": [ + 46, + 580, + 287, + 652 + ], + "type": "text", + "content": "Geometric Interpretation of (10). The line projection with the camera center define a plane, and this plane gives a line at infinity. Since the three lines in three views should correspond to the same 3D line, the three lines at infinity should intersect at the same point. In this case, we can obtain constraint (10)." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 659, + 148, + 672 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 659, + 148, + 672 + ], + "spans": [ + { + "bbox": [ + 47, + 659, + 148, + 672 + ], + "type": "text", + "content": "3.3. Degenerate Case" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 677, + 287, + 714 + ], + "type": "text", + "content": "A detailed analysis of the degeneracies for generalized two-view relative pose estimation has been shown in [10, 15]. The degenerated case is slightly different in" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": "generalized three-view relative pose problem. In our case, we found that if the multi-camera system undergoes pure translation " + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "inline_equation", + "content": "(\\mathbf{R}_2 = \\mathbf{R}_3 = \\mathbf{I})" + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": " with only intra-camera correspondences, our solvers can not recover the scale of the translation. However, if we only have " + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "inline_equation", + "content": "\\mathbf{R}_2 = \\mathbf{I}" + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": " or " + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "inline_equation", + "content": "\\mathbf{R}_3 = \\mathbf{I}" + }, + { + "bbox": [ + 304, + 72, + 545, + 144 + ], + "type": "text", + "content": ", our solvers can still recover the translation with scale factor." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 153, + 454, + 167 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 153, + 454, + 167 + ], + "spans": [ + { + "bbox": [ + 305, + 153, + 454, + 167 + ], + "type": "text", + "content": "4. Polynomial System Solver" + } + ] + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 318, + 182, + 533, + 268 + ], + "blocks": [ + { + "bbox": [ + 318, + 182, + 533, + 268 + ], + "lines": [ + { + "bbox": [ + 318, + 182, + 533, + 268 + ], + "spans": [ + { + "bbox": [ + 318, + 182, + 533, + 268 + ], + "type": "image", + "image_path": "143b08a095f7f6656cad26d73d7121f34744207038f5ac6349058b01efbcd214.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 270, + 545, + 303 + ], + "lines": [ + { + "bbox": [ + 304, + 270, + 545, + 303 + ], + "spans": [ + { + "bbox": [ + 304, + 270, + 545, + 303 + ], + "type": "text", + "content": "Figure 3. A track (curve) of a Homotopy Continuation algorithm showing " + }, + { + "bbox": [ + 304, + 270, + 545, + 303 + ], + "type": "inline_equation", + "content": "H(X, t)" + }, + { + "bbox": [ + 304, + 270, + 545, + 303 + ], + "type": "text", + "content": " in black, along with one prediction (red) and one correction (blue)." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "spans": [ + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": "Homotopy Continuation: The idea of Homotopy Continuation (HC) [18, 24] is to evolve the solutions of one polynomial system " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "G" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": ", the \"start system\", to discover the solutions of another system " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "F" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": ", the \"target system\". Let " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "X = (x_{1}, x_{2}, \\ldots, x_{M})" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": " represent " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "M" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": " unknowns. Let " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "F(X)" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": " be a system of " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": " polynomial equations " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "F = (f_{1}, f_{2}, \\ldots, f_{N})" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": ". Let " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "G(x)" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "G = (g_{1}, g_{2}, \\ldots, g_{N})" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": " be the \"start system\" whose solutions are all known. The idea of HC is to construct a series of intermediate polynomial systems " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "H(X, t)" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "H = (H_{1}, H_{2}, \\ldots, H_{N})" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": "; where " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "H(X, 0) = G(X)" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "inline_equation", + "content": "H(X, 1) = F(X)" + }, + { + "bbox": [ + 305, + 315, + 545, + 448 + ], + "type": "text", + "content": ", e.g., via linear interpolation:" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 319, + 453, + 545, + 467 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 319, + 453, + 545, + 467 + ], + "spans": [ + { + "bbox": [ + 319, + 453, + 545, + 467 + ], + "type": "interline_equation", + "content": "H (x, t) = (1 - t) G (x) + t F (x), \\quad t \\in [ 0, 1 ]. \\tag {11}", + "image_path": "5e9ad685138c4c31fe831bff4b004322441e6f7ce191def5dac259ddbd27bc30.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "spans": [ + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": "The basic idea is to find the solution of " + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "inline_equation", + "content": "H(X, t + \\Delta t)" + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": " from the solution of " + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "inline_equation", + "content": "H(X, t)" + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": ". Figure 3 illustrates the idea for one solution and one unknown. The black curve is the locus of the solution " + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "inline_equation", + "content": "X(t)" + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": " of " + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "inline_equation", + "content": "H(X, t)" + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": ", the homotopy curve, where " + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "inline_equation", + "content": "X_0" + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": " is the known solution of " + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "inline_equation", + "content": "G(X)" + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "inline_equation", + "content": "X_1" + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": " is the desired solution of " + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "inline_equation", + "content": "F(X)" + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": ". We track solution " + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "inline_equation", + "content": "X_1" + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "inline_equation", + "content": "X_0" + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": " in a number of small steps, each consisting of a prediction and a correction step. Prediction uses a first-order Taylor expansion to estimate " + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "inline_equation", + "content": "X" + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": " at " + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "inline_equation", + "content": "t + \\Delta t" + }, + { + "bbox": [ + 304, + 472, + 545, + 581 + ], + "type": "text", + "content": " in the form of" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 362, + 586, + 545, + 601 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 362, + 586, + 545, + 601 + ], + "spans": [ + { + "bbox": [ + 362, + 586, + 545, + 601 + ], + "type": "interline_equation", + "content": "X ^ {*} (t + \\Delta t) = X (t) + \\frac {d X}{d t} \\Delta t, \\tag {12}", + "image_path": "308ddb1ce9d18eacb8c25e5ca3511ff53924eba04cf35c59170f48d8a56a4a5a.jpg" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 606, + 545, + 632 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 606, + 545, + 632 + ], + "spans": [ + { + "bbox": [ + 304, + 606, + 545, + 632 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 606, + 545, + 632 + ], + "type": "inline_equation", + "content": "X^{*}" + }, + { + "bbox": [ + 304, + 606, + 545, + 632 + ], + "type": "text", + "content": " is the first order estimation of " + }, + { + "bbox": [ + 304, + 606, + 545, + 632 + ], + "type": "inline_equation", + "content": "X(t + \\Delta t)" + }, + { + "bbox": [ + 304, + 606, + 545, + 632 + ], + "type": "text", + "content": ". We obtain " + }, + { + "bbox": [ + 304, + 606, + 545, + 632 + ], + "type": "inline_equation", + "content": "\\frac{dX}{dt}" + }, + { + "bbox": [ + 304, + 606, + 545, + 632 + ], + "type": "text", + "content": " by differentiating " + }, + { + "bbox": [ + 304, + 606, + 545, + 632 + ], + "type": "inline_equation", + "content": "H(X(t),t)" + }, + { + "bbox": [ + 304, + 606, + 545, + 632 + ], + "type": "text", + "content": ", i.e.," + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 317, + 635, + 545, + 662 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 635, + 545, + 662 + ], + "spans": [ + { + "bbox": [ + 317, + 635, + 545, + 662 + ], + "type": "interline_equation", + "content": "\\frac {\\partial H}{\\partial X} \\frac {d X}{d t} + \\frac {\\partial H}{\\partial t} = 0 \\longrightarrow \\frac {d X}{d t} = - \\left(\\frac {\\partial H}{\\partial X}\\right) ^ {- 1} \\frac {\\partial H}{\\partial t}, \\tag {13}", + "image_path": "4f009f37c717f0b80f9faf2a6ed8fadc1b0fdb91c2f72a07c08697355d5ca44f.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 666, + 545, + 681 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 666, + 545, + 681 + ], + "spans": [ + { + "bbox": [ + 306, + 666, + 545, + 681 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 306, + 666, + 545, + 681 + ], + "type": "inline_equation", + "content": "J = \\frac{\\partial H}{\\partial x}" + }, + { + "bbox": [ + 306, + 666, + 545, + 681 + ], + "type": "text", + "content": " is the " + }, + { + "bbox": [ + 306, + 666, + 545, + 681 + ], + "type": "inline_equation", + "content": "M \\times N" + }, + { + "bbox": [ + 306, + 666, + 545, + 681 + ], + "type": "text", + "content": " Jacobian of " + }, + { + "bbox": [ + 306, + 666, + 545, + 681 + ], + "type": "inline_equation", + "content": "H" + }, + { + "bbox": [ + 306, + 666, + 545, + 681 + ], + "type": "text", + "content": " wrt " + }, + { + "bbox": [ + 306, + 666, + 545, + 681 + ], + "type": "inline_equation", + "content": "X" + }, + { + "bbox": [ + 306, + 666, + 545, + 681 + ], + "type": "text", + "content": ", giving" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 346, + 696, + 545, + 712 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 346, + 696, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 346, + 696, + 545, + 712 + ], + "type": "interline_equation", + "content": "X ^ {*} (t + \\Delta t) = X (t) - \\left(\\frac {\\partial H}{\\partial X}\\right) ^ {- 1} \\frac {\\partial H}{\\partial t} \\Delta t. \\tag {14}", + "image_path": "58d01ac418d4137195be83559dc6986ee8256cdcfca63a204f51f3bd12328561.jpg" + } + ] + } + ], + "index": 21 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 315, + 757 + ], + "type": "text", + "content": "8159" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 289, + 144 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 289, + 144 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 289, + 144 + ], + "type": "text", + "content": "The first-order estimation of " + }, + { + "bbox": [ + 46, + 72, + 289, + 144 + ], + "type": "inline_equation", + "content": "X^{*}" + }, + { + "bbox": [ + 46, + 72, + 289, + 144 + ], + "type": "text", + "content": " from " + }, + { + "bbox": [ + 46, + 72, + 289, + 144 + ], + "type": "inline_equation", + "content": "X(t)" + }, + { + "bbox": [ + 46, + 72, + 289, + 144 + ], + "type": "text", + "content": " is known as the prediction step (Figure 3) which can be further improved using a higher-order method such as a fourth order Runge-Kutta. Followed by a correction step which helps improve the prediction, Newton's update " + }, + { + "bbox": [ + 46, + 72, + 289, + 144 + ], + "type": "inline_equation", + "content": "X^{*}(t + \\Delta t)" + }, + { + "bbox": [ + 46, + 72, + 289, + 144 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 72, + 289, + 144 + ], + "type": "inline_equation", + "content": "\\hat{X}(t + \\Delta t)" + }, + { + "bbox": [ + 46, + 72, + 289, + 144 + ], + "type": "text", + "content": " is used, i.e.," + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 54, + 148, + 287, + 165 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 54, + 148, + 287, + 165 + ], + "spans": [ + { + "bbox": [ + 54, + 148, + 287, + 165 + ], + "type": "interline_equation", + "content": "H \\left(X ^ {*}, t + \\Delta t\\right) + \\frac {\\partial H}{\\partial X} \\left(X ^ {*}, t + \\Delta t\\right) \\left(\\hat {X} - X ^ {*}\\right) = 0, \\tag {15}", + "image_path": "f68eb2fe41302e3c573985ce12e1d640bfd1a5c136d03a490f81eaa7ad4f694a.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 171, + 197, + 183 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 171, + 197, + 183 + ], + "spans": [ + { + "bbox": [ + 47, + 171, + 197, + 183 + ], + "type": "text", + "content": "giving the estimate " + }, + { + "bbox": [ + 47, + 171, + 197, + 183 + ], + "type": "inline_equation", + "content": "\\hat{X}" + }, + { + "bbox": [ + 47, + 171, + 197, + 183 + ], + "type": "text", + "content": " in the form of" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 58, + 187, + 287, + 203 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 187, + 287, + 203 + ], + "spans": [ + { + "bbox": [ + 58, + 187, + 287, + 203 + ], + "type": "interline_equation", + "content": "\\hat {X} = X ^ {*} - \\left(\\frac {\\partial H}{\\partial X}\\right) ^ {- 1} \\left(X ^ {*}, t + \\Delta t\\right) H \\left(X ^ {*}, t + \\Delta t\\right). \\tag {16}", + "image_path": "7e4ce73e00f17f773ddfdf3d6a7ee47c1bbdddfb9de239e8b7d7b385ecf36ed3.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 208, + 287, + 316 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 208, + 287, + 316 + ], + "spans": [ + { + "bbox": [ + 46, + 208, + 287, + 316 + ], + "type": "text", + "content": "The pairs of prediction and correction numerically evolve " + }, + { + "bbox": [ + 46, + 208, + 287, + 316 + ], + "type": "inline_equation", + "content": "X_0" + }, + { + "bbox": [ + 46, + 208, + 287, + 316 + ], + "type": "text", + "content": " as the solution of " + }, + { + "bbox": [ + 46, + 208, + 287, + 316 + ], + "type": "inline_equation", + "content": "G(X)" + }, + { + "bbox": [ + 46, + 208, + 287, + 316 + ], + "type": "text", + "content": " to " + }, + { + "bbox": [ + 46, + 208, + 287, + 316 + ], + "type": "inline_equation", + "content": "X_1" + }, + { + "bbox": [ + 46, + 208, + 287, + 316 + ], + "type": "text", + "content": " as the solution of " + }, + { + "bbox": [ + 46, + 208, + 287, + 316 + ], + "type": "inline_equation", + "content": "F(X)" + }, + { + "bbox": [ + 46, + 208, + 287, + 316 + ], + "type": "text", + "content": ". HC algorithms find all the solutions (up to some approximation) with probability one given a good start system which can be provided easily by a monodromy solver [1]. In many computer vision applications, a good start system usually needs to be created once as multiple target systems correspond to different target parameters can be solved from the same start system under a RANSAC loop." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 317, + 287, + 402 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 317, + 287, + 402 + ], + "spans": [ + { + "bbox": [ + 46, + 317, + 287, + 402 + ], + "type": "text", + "content": "GPU-HC: The iterative nature of HC prevents it from being practically used. The GPU implementation in [2, 3] parallelizes (i) HC paths and (ii) the evaluations of " + }, + { + "bbox": [ + 46, + 317, + 287, + 402 + ], + "type": "inline_equation", + "content": "\\frac{\\partial H}{\\partial X}" + }, + { + "bbox": [ + 46, + 317, + 287, + 402 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 46, + 317, + 287, + 402 + ], + "type": "inline_equation", + "content": "\\frac{\\partial H}{\\partial t}" + }, + { + "bbox": [ + 46, + 317, + 287, + 402 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 317, + 287, + 402 + ], + "type": "inline_equation", + "content": "H" + }, + { + "bbox": [ + 46, + 317, + 287, + 402 + ], + "type": "text", + "content": ", Equations (13) and (16) to enable HC efficiently solves problems whose complexity has far evaded a practical solution. We thus use GPU-HC as our minimal problem solver, giving promising results in our experiments." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 403, + 287, + 523 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 403, + 287, + 523 + ], + "spans": [ + { + "bbox": [ + 46, + 403, + 287, + 523 + ], + "type": "text", + "content": "GPU-HC Solution Refinement: Since GPU computation is memory-bound, extending numerical precision in GPU computation would significantly drag down efficiency. To obtain high numerical accuracy while avoiding slowdown, Levenberg-Marquardt algorithm using double precision is used, followed by GPU-HC using single precision for solution refinement. This refinement step can be done in CPU side efficiently as only partial GPU-HC solutions are necessary to be refined, i.e., real solutions in the 6-line problem or real and positive solutions in the 4-point problem." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 532, + 128, + 545 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 532, + 128, + 545 + ], + "spans": [ + { + "bbox": [ + 47, + 532, + 128, + 545 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 552, + 287, + 611 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 552, + 287, + 611 + ], + "spans": [ + { + "bbox": [ + 46, + 552, + 287, + 611 + ], + "type": "text", + "content": "To demonstrate that the proposed solvers work well in practice, we conduct extensive experiments on both synthetic and real-world data with multi-camera system configuration. Experiments are run on a 16-Core 3.6GHz Intel i7-11700K CPU and a NVIDIA Titan V GPU." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 612, + 287, + 636 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 612, + 287, + 636 + ], + "spans": [ + { + "bbox": [ + 47, + 612, + 287, + 636 + ], + "type": "text", + "content": "For both synthetic and real experiments, the solver's performance is evaluated by the following criteria:" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 80, + 640, + 252, + 711 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 80, + 640, + 252, + 711 + ], + "spans": [ + { + "bbox": [ + 80, + 640, + 252, + 711 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\xi_ {\\mathbf {R} [ \\mathrm {d e g} ]} = 2 \\arcsin \\left(\\frac {\\| \\mathbf {R} _ {g t} - \\mathbf {R} _ {e} \\|}{2 \\sqrt {2}}\\right), \\\\ \\xi_ {\\mathbf {t} [ \\mathrm {d e g} ]} = 2 \\arcsin \\left(\\frac {1}{2} \\left\\| \\frac {\\mathbf {t} _ {e}}{\\| \\mathbf {t} _ {e} \\|} - \\frac {\\mathbf {t} _ {g}}{\\| \\mathbf {t} _ {g} \\|} \\right\\|\\right), \\\\ \\xi_ {\\text {S c a l e}} = \\operatorname {a b s} \\left(\\| \\mathbf {t} _ {e} \\| / \\| \\mathbf {t} _ {g t} \\| - 1\\right), \\\\ \\end{array}", + "image_path": "8865c293bf07df3205e64cfd3ba8e5a59652c02638516ef0a6bc46ecc576eb2e.jpg" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "inline_equation", + "content": "\\xi_{\\mathbf{R}}" + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "inline_equation", + "content": "\\xi_{\\mathbf{t}}" + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "inline_equation", + "content": "\\xi_{\\mathrm{Scale}}" + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "content": " are the angle difference in rotation, direction difference in translation and relative scale error, respectively. " + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "inline_equation", + "content": "\\mathbf{R}_{gt}, \\mathbf{t}_{gt}" + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "content": " are the ground truth rotation and translation, and " + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "inline_equation", + "content": "\\mathbf{R}_e, \\mathbf{t}_e" + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "content": " are the estimated rotation and translation, respectively. All the norms are Frobenius norm. Note that, computing the rotation angle error and the translation direction error based on the " + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "inline_equation", + "content": "\\arccos\\left((\\operatorname{trace}(\\mathbf{R}_{\\mathrm{gt}}^\\top \\mathbf{R}_{\\mathrm{e}}) - 1)/2\\right)" + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "content": " is simpler. However, it's not the best choice. For example, if the relative angle between the rotation matrices is small, " + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "inline_equation", + "content": "\\left((\\operatorname{trace}(\\mathbf{R}_{\\mathrm{gt}}^\\top \\mathbf{R}_{\\mathrm{e}}) - 1)/2\\right)" + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "content": " is close to unity in that case and the " + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "inline_equation", + "content": "\\arccos" + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "content": " is very sensitive to errors. Hence, it's better to compute angular errors using the " + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "inline_equation", + "content": "\\arcsin" + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "content": " formulation. Detailed comparisons between " + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "inline_equation", + "content": "\\arcsin" + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "inline_equation", + "content": "\\arccos" + }, + { + "bbox": [ + 304, + 72, + 545, + 252 + ], + "type": "text", + "content": " are shown in the supplementary material." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 305, + 263, + 492, + 276 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 263, + 492, + 276 + ], + "spans": [ + { + "bbox": [ + 305, + 263, + 492, + 276 + ], + "type": "text", + "content": "5.1. Numerical Accuracy of the Solvers" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 282, + 545, + 463 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 282, + 545, + 463 + ], + "spans": [ + { + "bbox": [ + 304, + 282, + 545, + 463 + ], + "type": "text", + "content": "Although it has been reported in [2, 3] that GPU-HC provides promising and acceptable numerical accuracy in solving various minimal problems in computer vision, for the proposed problems to be usable the evaluation on polynomial residual is still necessary. Figure 4 top row shows the accuracy of (a) all GPU-HC converged solutions and (b) the converged solutions correspond to the ground truths, solving 6-line problem and 4-point problem using our synthetic dataset generating 10,000 real parameters for each problem. Both single precision (SP) and double precision (DP) are demonstrated, showing that the solver is able to provide less than " + }, + { + "bbox": [ + 304, + 282, + 545, + 463 + ], + "type": "inline_equation", + "content": "10^{-5}" + }, + { + "bbox": [ + 304, + 282, + 545, + 463 + ], + "type": "text", + "content": " accurate results for the majority of the GPU-HC solutions. Nevertheless, if a refinement step is involved, significant shifts in the distributions of residuals can be observed, Figure 4 bottom row, where single precision solu" + } + ] + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 313, + 479, + 421, + 564 + ], + "blocks": [ + { + "bbox": [ + 313, + 479, + 421, + 564 + ], + "lines": [ + { + "bbox": [ + 313, + 479, + 421, + 564 + ], + "spans": [ + { + "bbox": [ + 313, + 479, + 421, + 564 + ], + "type": "image", + "image_path": "d6b82679418a569165cafc6b33b73f03df1ff883338bdc50917e98762671e210.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 427, + 481, + 536, + 564 + ], + "blocks": [ + { + "bbox": [ + 427, + 481, + 536, + 564 + ], + "lines": [ + { + "bbox": [ + 427, + 481, + 536, + 564 + ], + "spans": [ + { + "bbox": [ + 427, + 481, + 536, + 564 + ], + "type": "image", + "image_path": "5d80cf1b275de1ada4719eb80a590656fda8398cdc8c176fe057c84755cf6ddd.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 312, + 569, + 421, + 654 + ], + "blocks": [ + { + "bbox": [ + 312, + 569, + 421, + 654 + ], + "lines": [ + { + "bbox": [ + 312, + 569, + 421, + 654 + ], + "spans": [ + { + "bbox": [ + 312, + 569, + 421, + 654 + ], + "type": "image", + "image_path": "595d8b5806d93541377dc477cf22a70792c2974174943537403f9e5954bfe3aa.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 365, + 661, + 376, + 669 + ], + "lines": [ + { + "bbox": [ + 365, + 661, + 376, + 669 + ], + "spans": [ + { + "bbox": [ + 365, + 661, + 376, + 669 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_caption" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 427, + 569, + 536, + 654 + ], + "blocks": [ + { + "bbox": [ + 427, + 569, + 536, + 654 + ], + "lines": [ + { + "bbox": [ + 427, + 569, + 536, + 654 + ], + "spans": [ + { + "bbox": [ + 427, + 569, + 536, + 654 + ], + "type": "image", + "image_path": "c2c03cecc966503d9fb72029efa09bd2c851ebeed80e3d28ee6c48e0f6b43b76.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 481, + 661, + 492, + 669 + ], + "lines": [ + { + "bbox": [ + 481, + 661, + 492, + 669 + ], + "spans": [ + { + "bbox": [ + 481, + 661, + 492, + 669 + ], + "type": "text", + "content": "(b)" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 305, + 669, + 545, + 712 + ], + "lines": [ + { + "bbox": [ + 305, + 669, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 305, + 669, + 545, + 712 + ], + "type": "text", + "content": "Figure 4. Numerical accuracy of GPU-HC from (a) all converged paths and (b) converged paths correspond to the true solution of the 4-points and 6-lines problems. Top Row: Original. Bottom Row: Refinement." + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_caption" + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8160" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 255, + 84 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 255, + 84 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 255, + 84 + ], + "type": "text", + "content": "tions are nearly as accurate as the double precision." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 92, + 168, + 105 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 92, + 168, + 105 + ], + "spans": [ + { + "bbox": [ + 47, + 92, + 168, + 105 + ], + "type": "text", + "content": "5.2. Synthetic Evaluation" + } + ] + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 50, + 111, + 159, + 192 + ], + "blocks": [ + { + "bbox": [ + 50, + 111, + 159, + 192 + ], + "lines": [ + { + "bbox": [ + 50, + 111, + 159, + 192 + ], + "spans": [ + { + "bbox": [ + 50, + 111, + 159, + 192 + ], + "type": "image", + "image_path": "c60b7a8d33ac9e0e28ad0006c3807866adf14ca23c5531b6d305796371542695.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 167, + 111, + 276, + 192 + ], + "blocks": [ + { + "bbox": [ + 167, + 111, + 276, + 192 + ], + "lines": [ + { + "bbox": [ + 167, + 111, + 276, + 192 + ], + "spans": [ + { + "bbox": [ + 167, + 111, + 276, + 192 + ], + "type": "image", + "image_path": "50e8d6d67d33d7178aebfeaa045c5facaf20f07c9d6711598e78e24f12ab4386.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 49, + 198, + 158, + 280 + ], + "blocks": [ + { + "bbox": [ + 49, + 198, + 158, + 280 + ], + "lines": [ + { + "bbox": [ + 49, + 198, + 158, + 280 + ], + "spans": [ + { + "bbox": [ + 49, + 198, + 158, + 280 + ], + "type": "image", + "image_path": "ad645e44c35c5f86e544be9d1e449e1ca98f50d5a4ef8329eaa97419eb202fd0.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 282, + 287, + 315 + ], + "lines": [ + { + "bbox": [ + 46, + 282, + 287, + 315 + ], + "spans": [ + { + "bbox": [ + 46, + 282, + 287, + 315 + ], + "type": "text", + "content": "Figure 5. Relative errors with noise-free data under random points and movement. Top Row: The 4-point solver. Bottom Row: The 6-line solver." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 167, + 195, + 276, + 280 + ], + "blocks": [ + { + "bbox": [ + 167, + 195, + 276, + 280 + ], + "lines": [ + { + "bbox": [ + 167, + 195, + 276, + 280 + ], + "spans": [ + { + "bbox": [ + 167, + 195, + 276, + 280 + ], + "type": "image", + "image_path": "a660c9e32cc5595fdb69d8c38ac399183993ecd9ae872ca1a1497cc9fc6b7cc0.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 326, + 286, + 433 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 326, + 286, + 433 + ], + "spans": [ + { + "bbox": [ + 46, + 326, + 286, + 433 + ], + "type": "text", + "content": "In this section, we evaluate the numerical stability and the noise resilience of the proposed solvers. We simulated a multi-camera system with six cameras, and the focal length of each pinhole camera is set to " + }, + { + "bbox": [ + 46, + 326, + 286, + 433 + ], + "type": "inline_equation", + "content": "1000\\mathrm{px}" + }, + { + "bbox": [ + 46, + 326, + 286, + 433 + ], + "type": "text", + "content": ". To generate the scene we uniformly sample 3D points from the box " + }, + { + "bbox": [ + 46, + 326, + 286, + 433 + ], + "type": "inline_equation", + "content": "[-2,2]\\times [-2,2]\\times [3,6]" + }, + { + "bbox": [ + 46, + 326, + 286, + 433 + ], + "type": "text", + "content": " in each camera's local coordinate system. Then based on two points we can generate lines in each camera. Finally these points and lines are transformed with a random but feasible rotation and translation." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 435, + 286, + 508 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 435, + 286, + 508 + ], + "spans": [ + { + "bbox": [ + 46, + 435, + 286, + 508 + ], + "type": "text", + "content": "Stability. We randomly generated 1000 noise-free instances with different transformations. Figure 5 top row shows the distribution of the " + }, + { + "bbox": [ + 46, + 435, + 286, + 508 + ], + "type": "inline_equation", + "content": "\\log_{10}" + }, + { + "bbox": [ + 46, + 435, + 286, + 508 + ], + "type": "text", + "content": " relative errors of the 4-point solver, and Figure 5 bottom row shows the distribution of the " + }, + { + "bbox": [ + 46, + 435, + 286, + 508 + ], + "type": "inline_equation", + "content": "\\log_{10}" + }, + { + "bbox": [ + 46, + 435, + 286, + 508 + ], + "type": "text", + "content": " relative errors of the 6-line solver, respectively. We can see that both solvers are quite stable." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 510, + 287, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 510, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 510, + 287, + 713 + ], + "type": "text", + "content": "Noise resilience. In this experiment, we focused on four practical motions: general motion, forward motion (along the " + }, + { + "bbox": [ + 46, + 510, + 287, + 713 + ], + "type": "inline_equation", + "content": "z" + }, + { + "bbox": [ + 46, + 510, + 287, + 713 + ], + "type": "text", + "content": "-axis), sideways motion (along the " + }, + { + "bbox": [ + 46, + 510, + 287, + 713 + ], + "type": "inline_equation", + "content": "x" + }, + { + "bbox": [ + 46, + 510, + 287, + 713 + ], + "type": "text", + "content": "-axis), and semipure translation " + }, + { + "bbox": [ + 46, + 510, + 287, + 713 + ], + "type": "inline_equation", + "content": "(\\mathbf{R}_2 = \\mathbf{I})" + }, + { + "bbox": [ + 46, + 510, + 287, + 713 + ], + "type": "text", + "content": ". Fig. 6 shows the performance of the proposed 4-point solver and 6-line solver under increasing image noise with different standard deviation. We can see that the 4-point solver has almost similar error distributions for the four motions. The only difference is that the translation direction error is slightly larger under sideways motion and forward motion. Overall, the performance of the 4-point solver is stable under different motions with increasing image noise. By contrast, the 6-line solver is more sensitive to image noise, especially the translation direction error. This is possibly due to the noise that we added to the end points. If the points are close to each other, very small noise in the end points may result in extremely large errors in the line direction. Since the 6-line solver is sensitivity" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 72, + 545, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 96 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 96 + ], + "type": "text", + "content": "to noise, we will focus on the performance of the 4-point solver in the real experiments." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 99, + 545, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 99, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 304, + 99, + 545, + 266 + ], + "type": "text", + "content": "Complexity analysis and running times. The success rate of finding the HC solutions correspond to the ground truths and the overall timings of our GPU-HC solver is shown in Table 3. Typically, using double precision would give a slowdown in speed compared to single precision, but there are times where double precision is faster than single precision, e.g., the minimum GPU-HC time of 6-line problem. This is because the required number of HC steps is lesser when double precision is used which converges HC tracks faster. The speedup compared to Julia 8-core CPU HC solver in the table also demonstrate the benefit of using GPU-HC, which gives more than " + }, + { + "bbox": [ + 304, + 99, + 545, + 266 + ], + "type": "inline_equation", + "content": "150 \\times" + }, + { + "bbox": [ + 304, + 99, + 545, + 266 + ], + "type": "text", + "content": " speedup and " + }, + { + "bbox": [ + 304, + 99, + 545, + 266 + ], + "type": "inline_equation", + "content": "58 \\times" + }, + { + "bbox": [ + 304, + 99, + 545, + 266 + ], + "type": "text", + "content": " speedup for single precision of 6-line and 4-point problems, respectively, enabling real-time computation." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "spans": [ + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "content": "Success rate and accuracy under a RANSAC scheme. Table 2 shows the RANSAC experiment of the 4-point problem using the synthetic dataset with image size " + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "inline_equation", + "content": "1000 \\times 1000" + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "content": " pixels. Among the projections of the 1000 synthetic generated scene points, the inliers are corrupted by uniformly distributed noise within a " + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "inline_equation", + "content": "7 \\times 7" + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "content": " window, while the outliers are corrupted by shifting the point by at least half the image size. 80 iterations is used for every case running 1000 times, and a successful RANSAC estimation is decided if " + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "inline_equation", + "content": "\\xi_{\\mathbf{R}[\\mathrm{deg}]} < 2" + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "content": " degrees. The table shows only " + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "inline_equation", + "content": "\\mathbf{R}_2" + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "inline_equation", + "content": "\\mathbf{t}_2" + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "inline_equation", + "content": "\\mathbf{s}_2" + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "content": " since they share similar accuracy with " + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "inline_equation", + "content": "\\mathbf{R}_3" + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "inline_equation", + "content": "\\mathbf{t}_3" + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "inline_equation", + "content": "\\mathbf{s}_3" + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "content": ". The errors are the averaged accuracy of successful cases which show that below " + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "inline_equation", + "content": "70\\%" + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "content": " outlier ratio the success rate has more than " + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "inline_equation", + "content": "80\\%" + }, + { + "bbox": [ + 304, + 268, + 545, + 448 + ], + "type": "text", + "content": ", and as long as inlier points are picked, the estimation accuracy is very promising." + } + ] + } + ], + "index": 12 + }, + { + "type": "table", + "bbox": [ + 309, + 458, + 545, + 579 + ], + "blocks": [ + { + "bbox": [ + 309, + 458, + 545, + 579 + ], + "lines": [ + { + "bbox": [ + 309, + 458, + 545, + 579 + ], + "spans": [ + { + "bbox": [ + 309, + 458, + 545, + 579 + ], + "type": "table", + "html": "
Outlier RatioSuccess Rate\\( {\\xi }_{\\mathbf{R}\\left\\lbrack \\mathrm{{deg}}\\right\\rbrack } \\)\\( {\\xi }_{\\mathbf{t}\\left\\lbrack \\mathrm{{deg}}\\right\\rbrack } \\)\\( {\\xi }_{\\text{Scale }} \\)
10%100%0.1930.0180.009
20%100%0.1990.1330.076
30%100%0.5740.1880.175
40%96.4%0.9970.1590.122
50%90.7%1.3440.4420.169
60%87.1%1.1280.1340.137
70%81.4%0.8950.1430.060
80%66.3%1.4950.3280.329
90%42.7%1.7490.1340.139
", + "image_path": "7952f2d8fff315222462565ff9eada0012a2a23e31f7f1ce9f3b01717d5dc98c.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_body" + } + ], + "index": 13 + }, + { + "bbox": [ + 305, + 586, + 545, + 609 + ], + "lines": [ + { + "bbox": [ + 305, + 586, + 545, + 609 + ], + "spans": [ + { + "bbox": [ + 305, + 586, + 545, + 609 + ], + "type": "text", + "content": "Table 2. Performance of the 4-point problem under a RANSAC scheme given different outlier ratios using the synthetic dataset." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 306, + 618, + 443, + 631 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 618, + 443, + 631 + ], + "spans": [ + { + "bbox": [ + 306, + 618, + 443, + 631 + ], + "type": "text", + "content": "5.3. Real-world Experiments" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 634, + 545, + 694 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 634, + 545, + 694 + ], + "spans": [ + { + "bbox": [ + 304, + 634, + 545, + 694 + ], + "type": "text", + "content": "In order to test the proposed technique on real-world data, we chose the LaMAR [22] dataset, which contains both indoor and outdoor images with illumination and semantic changes as well as dynamic objects. We used the image sequences captured by a multi-camera rig (HoloLens 2)." + } + ] + } + ], + "index": 16 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 317, + 702, + 428, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 702, + 428, + 712 + ], + "spans": [ + { + "bbox": [ + 317, + 702, + 428, + 712 + ], + "type": "text", + "content": "1https://lamar.ethz.ch/" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 314, + 757 + ], + "type": "text", + "content": "8161" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 52, + 69, + 171, + 163 + ], + "blocks": [ + { + "bbox": [ + 52, + 69, + 171, + 163 + ], + "lines": [ + { + "bbox": [ + 52, + 69, + 171, + 163 + ], + "spans": [ + { + "bbox": [ + 52, + 69, + 171, + 163 + ], + "type": "image", + "image_path": "e80d3067e31837f045a56494858c800afa262c28eccbc111417337c5a3c69804.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 175, + 69, + 294, + 163 + ], + "blocks": [ + { + "bbox": [ + 175, + 69, + 294, + 163 + ], + "lines": [ + { + "bbox": [ + 175, + 69, + 294, + 163 + ], + "spans": [ + { + "bbox": [ + 175, + 69, + 294, + 163 + ], + "type": "image", + "image_path": "97dbae3c86f767a35572132213b9dbf519877e07d55486f044a3d6bcb87fb7d6.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 299, + 69, + 419, + 163 + ], + "blocks": [ + { + "bbox": [ + 299, + 69, + 419, + 163 + ], + "lines": [ + { + "bbox": [ + 299, + 69, + 419, + 163 + ], + "spans": [ + { + "bbox": [ + 299, + 69, + 419, + 163 + ], + "type": "image", + "image_path": "2566f398addc4ce68565ba3c2d847f95e21f919b2920e31d245ff8266da530d6.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 423, + 70, + 542, + 163 + ], + "blocks": [ + { + "bbox": [ + 423, + 70, + 542, + 163 + ], + "lines": [ + { + "bbox": [ + 423, + 70, + 542, + 163 + ], + "spans": [ + { + "bbox": [ + 423, + 70, + 542, + 163 + ], + "type": "image", + "image_path": "6c73f3f6280722a7a4593402a56ead53ecbaa43cfb4ab86657baef2269ccc816.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 51, + 164, + 171, + 256 + ], + "blocks": [ + { + "bbox": [ + 51, + 164, + 171, + 256 + ], + "lines": [ + { + "bbox": [ + 51, + 164, + 171, + 256 + ], + "spans": [ + { + "bbox": [ + 51, + 164, + 171, + 256 + ], + "type": "image", + "image_path": "8bee8e685e0145f1b460b685051966f1e3bfc45b94c63b9d439db50bbdf4bbae.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 176, + 164, + 294, + 256 + ], + "blocks": [ + { + "bbox": [ + 176, + 164, + 294, + 256 + ], + "lines": [ + { + "bbox": [ + 176, + 164, + 294, + 256 + ], + "spans": [ + { + "bbox": [ + 176, + 164, + 294, + 256 + ], + "type": "image", + "image_path": "34f6cd00b14068689e95e19adbccc35d8de864a52879c5a19500331914e7d6d8.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 299, + 164, + 418, + 256 + ], + "blocks": [ + { + "bbox": [ + 299, + 164, + 418, + 256 + ], + "lines": [ + { + "bbox": [ + 299, + 164, + 418, + 256 + ], + "spans": [ + { + "bbox": [ + 299, + 164, + 418, + 256 + ], + "type": "image", + "image_path": "2428c96a26cb7bf4e06bd4c3ed03ec7d8e8265e902779042f700f65083bb2c89.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 423, + 164, + 542, + 256 + ], + "blocks": [ + { + "bbox": [ + 423, + 164, + 542, + 256 + ], + "lines": [ + { + "bbox": [ + 423, + 164, + 542, + 256 + ], + "spans": [ + { + "bbox": [ + 423, + 164, + 542, + 256 + ], + "type": "image", + "image_path": "cfe207372c97c4ee4afeaec9dfc72e54ddf01335ffe7efea0bb9fc5c4b54cb23.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 51, + 257, + 171, + 364 + ], + "blocks": [ + { + "bbox": [ + 51, + 257, + 171, + 364 + ], + "lines": [ + { + "bbox": [ + 51, + 257, + 171, + 364 + ], + "spans": [ + { + "bbox": [ + 51, + 257, + 171, + 364 + ], + "type": "image", + "image_path": "6fb4aeab4b40531941b9da83a9c1448521e4c817e4231e06ac4dd460f5854cd1.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 365, + 545, + 398 + ], + "lines": [ + { + "bbox": [ + 47, + 365, + 545, + 398 + ], + "spans": [ + { + "bbox": [ + 47, + 365, + 545, + 398 + ], + "type": "text", + "content": "Figure 6. Boxplot of the relative errors under increasing image noise with a maximum value of 1 pixel. Top Row: Rotation error in degree. Middle Row: Translation error in degree. Bottom Row: Translation scale error. From left column to right column are general motion, sideways motion, forward motion and semi-pure translation, respectively." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 176, + 257, + 294, + 364 + ], + "blocks": [ + { + "bbox": [ + 176, + 257, + 294, + 364 + ], + "lines": [ + { + "bbox": [ + 176, + 257, + 294, + 364 + ], + "spans": [ + { + "bbox": [ + 176, + 257, + 294, + 364 + ], + "type": "image", + "image_path": "62d11d488f366568cbc720979b5bb7503b16c8b4b3e79a5b4e6f77579b1cf4a6.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 299, + 257, + 418, + 364 + ], + "blocks": [ + { + "bbox": [ + 299, + 257, + 418, + 364 + ], + "lines": [ + { + "bbox": [ + 299, + 257, + 418, + 364 + ], + "spans": [ + { + "bbox": [ + 299, + 257, + 418, + 364 + ], + "type": "image", + "image_path": "b55620d740c2305d83599c3183a0652cef5ad2db26107539e38de0a66ab2ecce.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 423, + 257, + 542, + 364 + ], + "blocks": [ + { + "bbox": [ + 423, + 257, + 542, + 364 + ], + "lines": [ + { + "bbox": [ + 423, + 257, + 542, + 364 + ], + "spans": [ + { + "bbox": [ + 423, + 257, + 542, + 364 + ], + "type": "image", + "image_path": "246dd04e0e2ef3ce6dadd514cb6c6dcac0d59b57fc5bb84128dc2787eaec3662.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "table", + "bbox": [ + 50, + 407, + 544, + 494 + ], + "blocks": [ + { + "bbox": [ + 50, + 407, + 544, + 494 + ], + "lines": [ + { + "bbox": [ + 50, + 407, + 544, + 494 + ], + "spans": [ + { + "bbox": [ + 50, + 407, + 544, + 494 + ], + "type": "table", + "html": "
SolverSuccess Rate (%)# of real sols. (# of positive real sols.)GPU-HC Timings (ms)Mean Julia Timings (ms) (8-core CPU)Julia GPU-HC
minmaxmedianmeanminmaxmedianmean
4-point (DP)99.7834(4)93(12)68(8)68.5(8.1)9.632.816.817.4428.2624.6×
4-point (SP)99.0632(2)89(10)52(5)53.2(5.1)5.315.77.27.358.7×
6-line (DP)98.67521398787.72.972.435.434.1110332.3×
6-line (SP)97.63481208482.45.215.47.17.2153.2×
", + "image_path": "649786cd5735f617fe9d76161a5b82e20c3b488455b458fe0335379c9d014d7c.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "table_body" + } + ], + "index": 13 + }, + { + "bbox": [ + 131, + 500, + 457, + 511 + ], + "lines": [ + { + "bbox": [ + 131, + 500, + 457, + 511 + ], + "spans": [ + { + "bbox": [ + 131, + 500, + 457, + 511 + ], + "type": "text", + "content": "Table 3. Success rate of finding the true solutions and the timings of solving the problems." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "text" + }, + { + "type": "image", + "bbox": [ + 52, + 521, + 285, + 598 + ], + "blocks": [ + { + "bbox": [ + 52, + 521, + 285, + 598 + ], + "lines": [ + { + "bbox": [ + 52, + 521, + 285, + 598 + ], + "spans": [ + { + "bbox": [ + 52, + 521, + 285, + 598 + ], + "type": "image", + "image_path": "eed162769ab8ff218dc5e7f9898c721d9e7bcc80d24ce3095803f76adcdfb394.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 600, + 287, + 623 + ], + "lines": [ + { + "bbox": [ + 47, + 600, + 287, + 623 + ], + "spans": [ + { + "bbox": [ + 47, + 600, + 287, + 623 + ], + "type": "text", + "content": "Figure 7. An example of four images from the LaMAR CAB dataset captured by a multi-camera rig with four cameras." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 15 + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "content": "It has a specialized large field-of-view (FOV) multi-camera tracking rig with four cameras. In general, this dataset contains three large scale sequences including: (i) HGE, the ground floor of a historic university building consists of numerous large halls and broad esplanades on either side with " + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "inline_equation", + "content": "18000m^2" + }, + { + "bbox": [ + 46, + 629, + 288, + 715 + ], + "type": "text", + "content": ". (ii) CAB, a multi-story office building that features a variety of small and large offices, a kitchen, stor" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 524, + 545, + 668 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 524, + 545, + 668 + ], + "spans": [ + { + "bbox": [ + 304, + 524, + 545, + 668 + ], + "type": "text", + "content": "age rooms, and two courtyards with " + }, + { + "bbox": [ + 304, + 524, + 545, + 668 + ], + "type": "inline_equation", + "content": "12000m^2" + }, + { + "bbox": [ + 304, + 524, + 545, + 668 + ], + "type": "text", + "content": ". (iii) LIN, several blocks of an ancient town, characterized by shops, restaurants, and narrow passageways with " + }, + { + "bbox": [ + 304, + 524, + 545, + 668 + ], + "type": "inline_equation", + "content": "15000m^2" + }, + { + "bbox": [ + 304, + 524, + 545, + 668 + ], + "type": "text", + "content": ". To setup the experiments we extracted triplets of multi-camera images from the mapping set, where the ground-truth poses are available. From each trajectory in the mapping set we select consecutive triplets satisfying the following criteria; the distance between consecutive rigs is in " + }, + { + "bbox": [ + 304, + 524, + 545, + 668 + ], + "type": "inline_equation", + "content": "[0.2m, 5m]" + }, + { + "bbox": [ + 304, + 524, + 545, + 668 + ], + "type": "text", + "content": " and at least two image pairs have more than 50 matches. This yielded in total 1280 (CAB), 1537 (HGE) and 2213 (LIN) triplets for evaluation. Pairwise 2d-2d matches are established using the SIFT[16] implementation in [23]." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 545, + 715 + ], + "type": "text", + "content": "Since there are no related solvers for generalized three-view relative pose problem, we only compare the proposed 4-point solver with the two-view 6-point solver [25]." + } + ] + } + ], + "index": 19 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8162" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 58, + 79, + 210, + 182 + ], + "blocks": [ + { + "bbox": [ + 110, + 71, + 176, + 79 + ], + "lines": [ + { + "bbox": [ + 110, + 71, + 176, + 79 + ], + "spans": [ + { + "bbox": [ + 110, + 71, + 176, + 79 + ], + "type": "text", + "content": "Rotation error CDF" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 58, + 79, + 210, + 182 + ], + "lines": [ + { + "bbox": [ + 58, + 79, + 210, + 182 + ], + "spans": [ + { + "bbox": [ + 58, + 79, + 210, + 182 + ], + "type": "image", + "image_path": "b826bab8c9eab6bf88e0ca67da3a95153a3ddaf55496d24d95b9a3c7800eb588.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 223, + 79, + 374, + 182 + ], + "blocks": [ + { + "bbox": [ + 276, + 71, + 341, + 79 + ], + "lines": [ + { + "bbox": [ + 276, + 71, + 341, + 79 + ], + "spans": [ + { + "bbox": [ + 276, + 71, + 341, + 79 + ], + "type": "text", + "content": "Rotation error CDF" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 223, + 79, + 374, + 182 + ], + "lines": [ + { + "bbox": [ + 223, + 79, + 374, + 182 + ], + "spans": [ + { + "bbox": [ + 223, + 79, + 374, + 182 + ], + "type": "image", + "image_path": "5b99f1455a59e229e7d64b22810db520ae40776ed4abc74c5bcac839b82a24b2.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 388, + 79, + 539, + 182 + ], + "blocks": [ + { + "bbox": [ + 441, + 71, + 507, + 79 + ], + "lines": [ + { + "bbox": [ + 441, + 71, + 507, + 79 + ], + "spans": [ + { + "bbox": [ + 441, + 71, + 507, + 79 + ], + "type": "text", + "content": "Rotation error CDF" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 388, + 79, + 539, + 182 + ], + "lines": [ + { + "bbox": [ + 388, + 79, + 539, + 182 + ], + "spans": [ + { + "bbox": [ + 388, + 79, + 539, + 182 + ], + "type": "image", + "image_path": "514dba690399d98f4c468d334743c0d93b31db942adfc68768c8d6c03ed0f45e.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 60, + 193, + 208, + 291 + ], + "blocks": [ + { + "bbox": [ + 109, + 186, + 179, + 193 + ], + "lines": [ + { + "bbox": [ + 109, + 186, + 179, + 193 + ], + "spans": [ + { + "bbox": [ + 109, + 186, + 179, + 193 + ], + "type": "text", + "content": "Translation error CDF" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 60, + 193, + 208, + 291 + ], + "lines": [ + { + "bbox": [ + 60, + 193, + 208, + 291 + ], + "spans": [ + { + "bbox": [ + 60, + 193, + 208, + 291 + ], + "type": "image", + "image_path": "1d00a02b4777fa18067a25c39ef384a3161dc64669a503a2582b601ccf222f90.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 226, + 193, + 374, + 291 + ], + "blocks": [ + { + "bbox": [ + 275, + 186, + 345, + 193 + ], + "lines": [ + { + "bbox": [ + 275, + 186, + 345, + 193 + ], + "spans": [ + { + "bbox": [ + 275, + 186, + 345, + 193 + ], + "type": "text", + "content": "Translation error CDF" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 226, + 193, + 374, + 291 + ], + "lines": [ + { + "bbox": [ + 226, + 193, + 374, + 291 + ], + "spans": [ + { + "bbox": [ + 226, + 193, + 374, + 291 + ], + "type": "image", + "image_path": "7b754157eeed04b8947d757534d360e5ba3c6d6833187c10a9e141a0f55b0f9b.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 391, + 193, + 539, + 291 + ], + "blocks": [ + { + "bbox": [ + 440, + 186, + 510, + 193 + ], + "lines": [ + { + "bbox": [ + 440, + 186, + 510, + 193 + ], + "spans": [ + { + "bbox": [ + 440, + 186, + 510, + 193 + ], + "type": "text", + "content": "Translation error CDF" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 391, + 193, + 539, + 291 + ], + "lines": [ + { + "bbox": [ + 391, + 193, + 539, + 291 + ], + "spans": [ + { + "bbox": [ + 391, + 193, + 539, + 291 + ], + "type": "image", + "image_path": "821ab51c9a16a868cd20d18514fb454d4b5742653fa3384fd41e88829e814fe3.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 58, + 303, + 208, + 405 + ], + "blocks": [ + { + "bbox": [ + 116, + 295, + 170, + 304 + ], + "lines": [ + { + "bbox": [ + 116, + 295, + 170, + 304 + ], + "spans": [ + { + "bbox": [ + 116, + 295, + 170, + 304 + ], + "type": "text", + "content": "Scale error CDF" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 58, + 303, + 208, + 405 + ], + "lines": [ + { + "bbox": [ + 58, + 303, + 208, + 405 + ], + "spans": [ + { + "bbox": [ + 58, + 303, + 208, + 405 + ], + "type": "image", + "image_path": "f0fddc3935c2d788fde28344571dbcf1310f8ce2e86611356ffdf619b953a29c.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 133, + 411, + 153, + 419 + ], + "lines": [ + { + "bbox": [ + 133, + 411, + 153, + 419 + ], + "spans": [ + { + "bbox": [ + 133, + 411, + 153, + 419 + ], + "type": "text", + "content": "CAB" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 47, + 421, + 545, + 443 + ], + "lines": [ + { + "bbox": [ + 47, + 421, + 545, + 443 + ], + "spans": [ + { + "bbox": [ + 47, + 421, + 545, + 443 + ], + "type": "text", + "content": "Figure 8. The cumulative distribution functions of the rotation, translation and scale errors. Being accurate is interpreted as a curve close to the top-left corner." + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 223, + 303, + 374, + 405 + ], + "blocks": [ + { + "bbox": [ + 282, + 295, + 335, + 303 + ], + "lines": [ + { + "bbox": [ + 282, + 295, + 335, + 303 + ], + "spans": [ + { + "bbox": [ + 282, + 295, + 335, + 303 + ], + "type": "text", + "content": "Scale error CDF" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 223, + 303, + 374, + 405 + ], + "lines": [ + { + "bbox": [ + 223, + 303, + 374, + 405 + ], + "spans": [ + { + "bbox": [ + 223, + 303, + 374, + 405 + ], + "type": "image", + "image_path": "c6a28a8b98f151914c8a858c9b5d7d0b3cf1c124ca48f11914c7d8e52d004dd9.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 299, + 411, + 319, + 419 + ], + "lines": [ + { + "bbox": [ + 299, + 411, + 319, + 419 + ], + "spans": [ + { + "bbox": [ + 299, + 411, + 319, + 419 + ], + "type": "text", + "content": "HGE" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_caption" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 388, + 302, + 539, + 405 + ], + "blocks": [ + { + "bbox": [ + 447, + 295, + 501, + 303 + ], + "lines": [ + { + "bbox": [ + 447, + 295, + 501, + 303 + ], + "spans": [ + { + "bbox": [ + 447, + 295, + 501, + 303 + ], + "type": "text", + "content": "Scale error CDF" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 388, + 302, + 539, + 405 + ], + "lines": [ + { + "bbox": [ + 388, + 302, + 539, + 405 + ], + "spans": [ + { + "bbox": [ + 388, + 302, + 539, + 405 + ], + "type": "image", + "image_path": "9ee0ecb8ea935533f270653fb5263c9427a8a7ddb076ee5ccdf88da048741966.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + } + ], + "index": 17 + }, + { + "type": "table", + "bbox": [ + 52, + 450, + 282, + 557 + ], + "blocks": [ + { + "bbox": [ + 52, + 450, + 282, + 557 + ], + "lines": [ + { + "bbox": [ + 52, + 450, + 282, + 557 + ], + "spans": [ + { + "bbox": [ + 52, + 450, + 282, + 557 + ], + "type": "table", + "html": "
LaMARSolver\\( \\xi_R \\)\\( \\xi_t \\)\\( \\xi_S \\)InlierIter
CAB4-point0.541.650.63329105
6-point0.946.510.73317189
HGE4-point0.583.120.8039299
6-point0.978.250.85387193
LIN4-point0.462.010.72573100
6-point0.784.860.81535199
", + "image_path": "12e6f4d5b59f4cf5ea2953bb29e2c5ed9bce54d8ce1c6c287a4583b5fa82c276.jpg" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "table_body" + } + ], + "index": 21 + }, + { + "bbox": [ + 46, + 564, + 287, + 586 + ], + "lines": [ + { + "bbox": [ + 46, + 564, + 287, + 586 + ], + "spans": [ + { + "bbox": [ + 46, + 564, + 287, + 586 + ], + "type": "text", + "content": "Table 4. The median errors, the number of inliers and the number of RANSAC iterations on the LaMAR dataset." + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "text" + }, + { + "bbox": [ + 46, + 594, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 288, + 713 + ], + "type": "text", + "content": "To make a fair comparison, we use the solvers in a simple RANSAC framework with a maximum number of RANSAC iterations set to 500. The inlier-outlier threshold is set to 2 pixels. In Fig. 8, we show the cumulative distribution functions (CDF) of the rotation (in degrees), translation (in degrees) and scale errors on the three tested datasets. Being accurate is interpreted as a curve close to the top-left corner. The median errors are reported in Table 4. The proposed solver leads to more accurate results, more inliers and fewer iterations than the compared two-view method. Due" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 304, + 452, + 545, + 488 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 452, + 545, + 488 + ], + "spans": [ + { + "bbox": [ + 304, + 452, + 545, + 488 + ], + "type": "text", + "content": "to the lack of space we only show the results using intra correspondences. Results for inter correspondences and mean errors are shown in the supplementary material." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 304, + 490, + 545, + 525 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 490, + 545, + 525 + ], + "spans": [ + { + "bbox": [ + 304, + 490, + 545, + 525 + ], + "type": "text", + "content": "Limitations. The main limitation is that the refinement step is currently done in CPU. We will consider to include the refinement in the GPU computation in the future." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 306, + 527, + 378, + 539 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 527, + 378, + 539 + ], + "spans": [ + { + "bbox": [ + 306, + 527, + 378, + 539 + ], + "type": "text", + "content": "6. Conclusion" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 304, + 544, + 545, + 675 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 544, + 545, + 675 + ], + "spans": [ + { + "bbox": [ + 304, + 544, + 545, + 675 + ], + "type": "text", + "content": "We discuss minimal cases of generalized three-view relative pose estimation. In particular, we propose GPH-HC based solvers to the 4-point and 6-line cases. Experiments on thousands of image pairs from publicly available datasets show that the proposed three-view 4-point solver is superior to the state-of-the-art two-view 6-point solver. One goal of future research is to use the technique proposed in [11] to improve the efficiency. We believe that the proposed method is promising and will be a good complement to existing methods to improve the accuracy and stability of the structure from motion systems." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 304, + 677, + 545, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 545, + 712 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 545, + 712 + ], + "type": "text", + "content": "Acknowledgements. VL, KÅ received funding from ELLIIT. Kimia and Chien gratefully acknowledge the support of NSF award 1910530." + } + ] + } + ], + "index": 28 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8163" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 106, + 83 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 15, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 135 + ], + "type": "text", + "content": "[1] Paul Breiding and Sascha Timme. HomotopyContinuation.jl: A Package for Homotopy Continuation in Julia. In International Congress on Mathematical Software, pages 458-465. Springer, 2018." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 136, + 288, + 200 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 136, + 288, + 200 + ], + "spans": [ + { + "bbox": [ + 53, + 136, + 288, + 200 + ], + "type": "text", + "content": "[2] Chiang-Heng Chien, Hongyi Fan, Ahmad Abdelfattah, Elias Tsigaridas, Stanimire Tomov, and Benjamin Kimia. GPU-based homotopy continuation for minimal problems in computer vision. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 15765-15776, 2022." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 202, + 288, + 256 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 202, + 288, + 256 + ], + "spans": [ + { + "bbox": [ + 53, + 202, + 288, + 256 + ], + "type": "text", + "content": "[3] Chiang-Heng Chien, Hongyi Fan, Ahmad Abdelfattah, Elias Tsigaridas, Stanimire Tomov, and Benjamin Kimia. Parallel path tracking for homotopy continuation using GPU. In Proceedings of the International Symposium on Symbolic and Algebraic Computation, 2022." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 258, + 287, + 279 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 258, + 287, + 279 + ], + "spans": [ + { + "bbox": [ + 53, + 258, + 287, + 279 + ], + "type": "text", + "content": "[4] David A. Cox, John Little, and Donal O'shea. Using algebraic geometry. Springer Science & Business Media, 2006." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 280, + 287, + 323 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 280, + 287, + 323 + ], + "spans": [ + { + "bbox": [ + 53, + 280, + 287, + 323 + ], + "type": "text", + "content": "[5] Timothy Duff, Kathlen Kohn, Anton Leykin, and Tomas Pajdla. PLMP - Point-Line Minimal Problems in Complete Multi-View Visibility. In IEEE/CVF International Conference on Computer Vision (ICCV), 2019." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 324, + 287, + 389 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 324, + 287, + 389 + ], + "spans": [ + { + "bbox": [ + 53, + 324, + 287, + 389 + ], + "type": "text", + "content": "[6] Ricardo Fabbri, Timothy Duff, Hongyi Fan, Margaret H. Regan, David da C. de Pinho, Elias Tsigaridas, Charles W. Wampler, Jonathan D. Hauenstein, Peter J. Giblin, Benjamin Kimia, Anton Leykin, and Tomas Pajdla. Trifocal Relative Pose From Lines at Points. Trans. Pattern Analysis and Machine Intelligence (PAMI), 2022." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 391, + 287, + 434 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 391, + 287, + 434 + ], + "spans": [ + { + "bbox": [ + 53, + 391, + 287, + 434 + ], + "type": "text", + "content": "[7] Martin A Fischler and Robert C Bolles. Random sample consensus: a paradigm for model fitting with applications to image analysis and automated cartography. Communications of the ACM, 1981." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 436, + 287, + 479 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 436, + 287, + 479 + ], + "spans": [ + { + "bbox": [ + 53, + 436, + 287, + 479 + ], + "type": "text", + "content": "[8] Jonathan D Hauenstein and Margaret H Regan. Adaptive strategies for solving parameterized systems using homotopy continuation. Applied Mathematics and Computation, 332:19-34, 2018." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 480, + 287, + 512 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 480, + 287, + 512 + ], + "spans": [ + { + "bbox": [ + 53, + 480, + 287, + 512 + ], + "type": "text", + "content": "[9] Robert J. Holt and Arun N. Netravali. Motion and structure from line correspondences: Some further results. International Journal of Imaging Systems and Technology, 1994." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 514, + 287, + 556 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 514, + 287, + 556 + ], + "spans": [ + { + "bbox": [ + 48, + 514, + 287, + 556 + ], + "type": "text", + "content": "[10] Hongdong Li, Richard Hartley, and Jae-hak Kim. A linear approach to motion estimation using generalized camera models. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2008." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 558, + 287, + 601 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 558, + 287, + 601 + ], + "spans": [ + { + "bbox": [ + 48, + 558, + 287, + 601 + ], + "type": "text", + "content": "[11] Petr Hruby, Timothy Duff, Anton Leykin, and Tomas Pajdla. Learning to Solve Hard Minimal Problems. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2022." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 602, + 287, + 635 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 602, + 287, + 635 + ], + "spans": [ + { + "bbox": [ + 48, + 602, + 287, + 635 + ], + "type": "text", + "content": "[12] Zuzana Kukelova, Martin Bujnak, and Tomas Pajdla. Automatic generator of minimal problem solvers. In European Conference on Computer Vision (ECCV), 2008." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 636, + 287, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 636, + 287, + 679 + ], + "spans": [ + { + "bbox": [ + 48, + 636, + 287, + 679 + ], + "type": "text", + "content": "[13] Viktor Larsson, Kalle Åström, and Magnus Oskarsson. Efficient solvers for minimal problems by syzygy-based reduction. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2017." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "type": "text", + "content": "[14] Viktor Larsson, Magnus Oskarsson, Kalle Åström, Alge Wallis, Zuzana Kukelova, and Tomas Pajdla. Beyond gröbner bases: Basis selection for minimal solvers. In" + } + ] + } + ], + "index": 14 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 308, + 73, + 545, + 545 + ], + "type": "list", + "angle": 0, + "index": 29, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "text", + "content": "IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2018." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 308, + 96, + 545, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 96, + 545, + 140 + ], + "spans": [ + { + "bbox": [ + 308, + 96, + 545, + 140 + ], + "type": "text", + "content": "[15] Gim Hee Lee, Marc Pollefeys, and Friedrich Fraundorfer. Relative Pose Estimation for a Multi-camera System with Known Vertical Direction. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2014." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 308, + 141, + 545, + 173 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 141, + 545, + 173 + ], + "spans": [ + { + "bbox": [ + 308, + 141, + 545, + 173 + ], + "type": "text", + "content": "[16] David G Lowe. Distinctive image features from scale-invariant keypoints. International Journal of Computer Vision (IJCV), 2004." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 308, + 175, + 545, + 218 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 175, + 545, + 218 + ], + "spans": [ + { + "bbox": [ + 308, + 175, + 545, + 218 + ], + "type": "text", + "content": "[17] Branislav Micusik and Tomas Pajdla. Autocalibration & 3d reconstruction with non-central catadioptric cameras. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2004." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 308, + 220, + 545, + 251 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 220, + 545, + 251 + ], + "spans": [ + { + "bbox": [ + 308, + 220, + 545, + 251 + ], + "type": "text", + "content": "[18] Alexander Morgan. Solving polynomial systems using continuation for engineering and scientific problems. SIAM, 2009." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 308, + 254, + 545, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 254, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 308, + 254, + 545, + 285 + ], + "type": "text", + "content": "[19] David Nister and Frederik Schaffalitzky. Four Points in Two or Three Calibrated Views: Theory and Practice. International Journal of Computer Vision, 2006." + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 308, + 288, + 545, + 319 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 288, + 545, + 319 + ], + "spans": [ + { + "bbox": [ + 308, + 288, + 545, + 319 + ], + "type": "text", + "content": "[20] Robert Pless. Using many cameras as one. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2003." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 308, + 322, + 545, + 354 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 322, + 545, + 354 + ], + "spans": [ + { + "bbox": [ + 308, + 322, + 545, + 354 + ], + "type": "text", + "content": "[21] Long Quan, Bill Triggs, and Bernard Mourrain. Some Results on Minimal Euclidean Reconstruction from Four Points. Journal of Mathematical Imaging and Vision, 2006." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 308, + 355, + 545, + 410 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 355, + 545, + 410 + ], + "spans": [ + { + "bbox": [ + 308, + 355, + 545, + 410 + ], + "type": "text", + "content": "[22] Paul-Edouard Sarlin, Mihai Dusmanu, Johannes L. Schonberger, Pablo Speciale, Lukas Gruber, Viktor Larsson, Ondrej Miksik, and Marc Pollefeys. LaMAR: Benchmarking Localization and Mapping for Augmented Reality. In European Conference on Computer Vision (ECCV), 2022." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 308, + 411, + 545, + 443 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 411, + 545, + 443 + ], + "spans": [ + { + "bbox": [ + 308, + 411, + 545, + 443 + ], + "type": "text", + "content": "[23] Johannes L Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2016." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 308, + 445, + 545, + 477 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 445, + 545, + 477 + ], + "spans": [ + { + "bbox": [ + 308, + 445, + 545, + 477 + ], + "type": "text", + "content": "[24] Andrew J Sommese and Charles W Wampler. The Numerical solution of systems of polynomials arising in engineering and science. World Scientific, 2005." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 308, + 479, + 545, + 511 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 479, + 545, + 511 + ], + "spans": [ + { + "bbox": [ + 308, + 479, + 545, + 511 + ], + "type": "text", + "content": "[25] Henrik Stewenius, David Nister, Magnus Oskarsson, and Kalle Åström. Solutions to minimal generalized relative pose problems. In Workshop on omnidirectional vision, 2005." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 308, + 513, + 545, + 545 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 308, + 513, + 545, + 545 + ], + "spans": [ + { + "bbox": [ + 308, + 513, + 545, + 545 + ], + "type": "text", + "content": "[26] Peter Sturm. Multi-View Geometry for General Camera Models. In IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2005." + } + ] + } + ], + "index": 28 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "spans": [ + { + "bbox": [ + 295, + 748, + 315, + 757 + ], + "type": "text", + "content": "8164" + } + ] + } + ], + "index": 30 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/1ff0de2c-2b50-437f-a3e0-afb03703f817_content_list.json b/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/1ff0de2c-2b50-437f-a3e0-afb03703f817_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..20cb72e6bad7adc14d651248ace2f8b45130f4f6 --- /dev/null +++ b/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/1ff0de2c-2b50-437f-a3e0-afb03703f817_content_list.json @@ -0,0 +1,2369 @@ +[ + { + "type": "text", + "text": "Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles", + "text_level": 1, + "bbox": [ + 94, + 130, + 875, + 154 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Gaku Nakano", + "bbox": [ + 426, + 181, + 542, + 196 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "NEC Corporation", + "bbox": [ + 413, + 199, + 557, + 215 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1753 Shimonumabe, Kawasaki, Japan", + "bbox": [ + 336, + 215, + 635, + 234 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "g-nakano@nec.com", + "bbox": [ + 411, + 237, + 558, + 250 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 286, + 313, + 301 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "This paper proposes minimal solutions to uncalibrated two-view geometry with known epipoles. Exploiting the epipoles, we can reduce the number of point correspondences needed to find the fundamental matrix together with the intrinsic parameters: the focal length and the radial lens distortion. We define four cases by the number of available epipoles and unknown intrinsic parameters, then derive a closed-form solution for each case formulated as a higher-order polynomial in a single variable. The proposed solvers are more numerically stable and faster by orders of magnitude than the conventional 6- or 7-point algorithms. Moreover, we demonstrate by experiments on the human pose dataset that the proposed method can solve two-view geometry even with 2D human pose, of which point localization is noisier than general feature point detectors.", + "bbox": [ + 75, + 316, + 472, + 545 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 573, + 209, + 589 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Solving the two-view geometry of uncalibrated cameras is one of the basic tasks for many computer vision applications such as the structure-from-motion [1, 31], Visual-SLAM [6, 26], and novel view synthesis [4, 25]. The goal of this problem is to find the fundamental matrix and the intrinsic parameters of the two cameras from point correspondences. Since point correspondences are generally contaminated by outliers, many efforts have been devoted to develop efficient and numerically stable solvers that can be incorporated into RANSAC [9] to extract a set of inlier point pairs.", + "bbox": [ + 75, + 598, + 468, + 750 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "It is known that the fundamental matrix with an unknown focal length and known principal points can be determined by six point correspondences. Stewenius et al. [34] first developed a minimal solution to this problem by manually deriving Gröbner basis. Then, other methods were proposed based on various approaches, e.g. the hidden variable technique [23], the polynomial eigenvalue problem [19], the automatic generator [21]. Following the success of the 6-point algorithms, research interests have been expanded to deal with the radial lens distortion. Jiang et al. [15] and", + "bbox": [ + 75, + 750, + 470, + 901 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Kuang et al. [18] showed that the fundamental matrix with both unknown focal length and unknown radial distortion can be solved by seven point correspondences. However, with more intrinsic parameters to be estimated, new issues arise in terms of numerical stability and computational efficiency. The root cause is that those methods assume general conditions with no restrictions on the camera motion and thus cannot reduce the number of point correspondences.", + "bbox": [ + 496, + 287, + 893, + 409 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "To address the above issue, we assume that two cameras are mutually observed, as shown in Fig. 1. This is not a rare and limited situation but occurs in real applications. For example, multiple cameras are installed to capture human behaviors from $360^{\\circ}$ views in dataset creation (Figs. 2a and 2b). In dynamic scenes such as multi-agent Visual-SLAM, robots collaboratively create a single map of a wide area (Fig. 2c). Visual-SLAM can also be applied to calibrate camera networks consisting of fixed and moving cameras (Fig. 2d). In those scenarios, epipoles or 2D positions of the camera center are directly obtainable from images. Epipoles constrain a fundamental matrix to be rank-deficient, thus reducing the number of point correspondences. Nistér [27] showed a theory for finding a relative rotation of calibrated cameras with a single epipole. Ito et al. [14] utilized epipole(s) for fundamental matrix estimation, then Sato [30] generalized it to three- and four-view geometry. However, both methods are based on the DLT algorithm [11], thus not minimal solutions. They also do not address how to find the intrinsic parameters.", + "bbox": [ + 496, + 412, + 893, + 715 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In this paper, we propose minimal solutions utilizing epipole(s) to determine a fundamental matrix with unknown intrinsic camera parameters: focal length and radial lens distortion. The proposed method has four variations depending on the number of available epipoles and the number of unknown parameters to be estimated. Moreover, we introduce a simple regularization term to fix the epipoles during the non-linear optimization, which is conducted on inliers after RANSAC. Through exhaustive experiments, we show that the proposed algorithms provide more reliable estimations than the conventional methods while achieving a significant acceleration by orders of magnitude.", + "bbox": [ + 496, + 719, + 895, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 805, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "13361", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/d1df319f1136e9f5f6e4398f5f5a1a38be9a6888e895be889fa1feda70d86891.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 96, + 87, + 449, + 181 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/e8a164bc1c660ac212b69445da864d9b3d7ce00f9a1c207bc94b5d25f882ebc9.jpg", + "image_caption": [ + "(a) Single epipole case. The projection of the second camera is observed as $\\mathbf{e}$ in the first camera.", + "(b) Two epipoles case. The two cameras are mutually observed as e and $\\mathbf{e}^{\\prime}$ in each image." + ], + "image_footnote": [], + "bbox": [ + 96, + 215, + 449, + 311 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/cac7d0c5b923cf282edfbdebd8fc016dedb70a77078471817be11ab33ea4787f.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 78, + 376, + 236, + 469 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/b8d7c984d1775a217687fa17aede034ddedd54c5d2fc9df3febed38928dbe64e.jpg", + "image_caption": [ + "Figure 1. Two-view geometry with known epipoles." + ], + "image_footnote": [], + "bbox": [ + 250, + 375, + 457, + 468 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/dd78af87cf180d31da669a0e2ef406f1fd51f4c99c0952605a6bc53d2308d298.jpg", + "image_caption": [ + "(a) HumanEva [32]", + "(c) Collaborative Visual- (d) SLAM-based calibration for surveilSLAM [28, 36] lance and moving cameras [29]", + "Figure 2. Mutual camera projections in applications. (a)-(b): Human pose dataset. (c)-(d): Multi-agent Visual-SLAM." + ], + "image_footnote": [], + "bbox": [ + 78, + 488, + 235, + 580 + ], + "page_idx": 1 + }, + { + "type": "image", + "img_path": "images/b4817c98b48328fb9c351e75f0aa0cd0f927873ee2ac00dae49a68999ff9a749.jpg", + "image_caption": [ + "(b) Panoptic studio dataset [16]" + ], + "image_footnote": [], + "bbox": [ + 246, + 488, + 460, + 580 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Uncalibrated two-view geometry", + "text_level": 1, + "bbox": [ + 76, + 667, + 374, + 685 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "This section describes the theoretical background of two-view geometry for uncalibrated cameras. We represent 2D points as their homogeneous coordinates, i.e. $\\mathbf{m} = [u,v,1]^{\\mathrm{T}}$ , and assume a pinhole camera model whose intrinsic parameters are partially known: the principal point is approximated by the image center; the skewness is zero. Solving uncalibrated two-view geometry is to find the focal length $f$ and the radial lens distortion $k$ as well as the relative rotation $\\mathbb{R}$ and translation $\\mathfrak{t}$ between the two cameras.", + "bbox": [ + 76, + 693, + 467, + 827 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Given $n$ pairs of a 2D point correspondence $\\{\\mathbf{m}_i \\leftrightarrow \\mathbf{m}_i'\\}$ between the two cameras, each point pair is constrained by a $3 \\times 3$ fundamental matrix $\\mathbf{F}$ :", + "bbox": [ + 76, + 829, + 467, + 873 + ], + "page_idx": 1 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {m} _ {i} ^ {\\prime} ^ {\\top} \\mathbf {F m} _ {i} = \\left(\\mathbf {m} _ {i} ^ {\\prime} \\otimes \\mathbf {m} _ {i}\\right) ^ {\\top} \\mathbf {f} = 0, \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 166, + 882, + 468, + 902 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "where $\\otimes$ denotes the Kronecker product and $\\mathbf{f}$ is a 9-dim vector representation of $\\mathbf{F}$ .", + "bbox": [ + 500, + 90, + 890, + 119 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Epipoles, $\\mathbf{e} = [x,y,1]^{\\top}$ and $\\mathbf{e}' = [x',y',1]^{\\top}$ , are the 2D projections of the image center of one camera onto the image plane of the other camera, which satisfy", + "bbox": [ + 500, + 119, + 890, + 166 + ], + "page_idx": 1 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {F} \\mathbf {e} = \\mathbf {F} ^ {\\top} \\mathbf {e} ^ {\\prime} = \\mathbf {0}. \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 638, + 176, + 890, + 191 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Equation (2) leads to one of the constraints on $\\mathbf{F}$ , i.e. $\\operatorname*{det}(\\mathbf{F}) = 0$ . Thus, $\\mathbf{F}$ is of rank two.", + "bbox": [ + 500, + 204, + 888, + 233 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "When the two cameras can be assumed to have the same focal length $f$ , another constraint is given by", + "bbox": [ + 500, + 234, + 888, + 263 + ], + "page_idx": 1 + }, + { + "type": "equation", + "text": "\n$$\n2 F Q F ^ {\\top} Q F Q - \\operatorname {t r} \\left(F Q F ^ {\\top} Q\\right) F Q = 0, \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 586, + 273, + 890, + 290 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "where $\\mathbb{Q} = \\mathrm{diag}(f^2, f^2, 1)$ . Equation (3) is the necessary and sufficient conditions to recover $\\mathbf{R}$ and $\\mathbf{t}$ by decomposing $\\mathbf{F}$ . Eliminating $f$ , we can rewrite Eq. (3) in a closed-form w.r.t. $\\mathbf{F}$ [20] as follows:", + "bbox": [ + 498, + 301, + 890, + 359 + ], + "page_idx": 1 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} h (\\mathbf {F}) = F _ {1 1} F _ {1 3} ^ {3} F _ {3 1} + F _ {1 3} ^ {2} F _ {2 1} F _ {2 3} F _ {3 1} + F _ {1 1} F _ {1 3} F _ {2 3} ^ {2} F _ {3 1} \\\\ + F _ {2 1} F _ {2 3} ^ {3} F _ {3 1} - F _ {1 1} F _ {1 3} F _ {3 1} ^ {3} - F _ {2 1} F _ {2 3} F _ {3 1} ^ {3} + F _ {1 2} F _ {1 3} ^ {3} F _ {3 2} \\\\ + F _ {1 3} ^ {2} F _ {2 2} F _ {2 3} F _ {3 2} + F _ {1 2} F _ {1 3} F _ {2 3} ^ {2} F _ {3 2} + F _ {2 2} F _ {2 3} ^ {3} F _ {3 2} \\\\ - F _ {1 2} F _ {1 3} F _ {3 1} ^ {2} F _ {3 2} - F _ {2 2} F _ {2 3} F _ {3 1} ^ {2} F _ {3 2} - F _ {1 1} F _ {1 3} F _ {3 1} F _ {3 2} ^ {2} \\\\ - F _ {2 1} F _ {2 3} F _ {3 1} F _ {3 2} ^ {2} - F _ {1 2} F _ {1 3} F _ {3 2} ^ {3} - F _ {2 2} F _ {2 3} F _ {3 2} ^ {3} \\tag {4} \\\\ - F _ {1 1} ^ {2} F _ {1 3} ^ {2} F _ {3 3} - F _ {1 2} ^ {2} F _ {1 3} ^ {2} F _ {3 3} - 2 F _ {1 1} F _ {1 3} F _ {2 1} F _ {2 3} F _ {3 3} \\\\ - 2 F _ {1 2} F _ {1 3} F _ {2 2} F _ {2 3} F _ {3 3} - F _ {2 1} ^ {2} F _ {2 3} ^ {2} F _ {3 3} - F _ {2 2} ^ {2} F _ {2 3} ^ {2} F _ {3 3} \\\\ + F _ {1 1} ^ {2} F _ {3 1} ^ {2} F _ {3 3} + F _ {2 1} ^ {2} F _ {3 1} ^ {2} F _ {3 3} + 2 F _ {1 1} F _ {1 2} F _ {3 1} F _ {3 2} F _ {3 3} \\\\ + 2 F _ {2 1} F _ {2 2} F _ {3 1} F _ {3 2} F _ {3 3} + F _ {1 2} ^ {2} F _ {3 2} ^ {2} F _ {3 3} + F _ {2 2} ^ {2} F _ {3 2} ^ {2} F _ {3 3} = 0, \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 519, + 369, + 890, + 527 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "where $F_{ij}$ denotes the $(i,j)$ element of $\\mathbf{F}$ .", + "bbox": [ + 500, + 537, + 774, + 551 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Once we obtain an $\\mathbf{F}$ such that $\\operatorname*{det}(\\mathbb{F}) = 0$ and Eq. (3) (or Eq. (4)), the focal length $f$ can be computed in a closed-form [20]:", + "bbox": [ + 498, + 551, + 890, + 595 + ], + "page_idx": 1 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} F _ {1 2} F _ {1 3} F _ {3 3} ^ {2} + F _ {2 2} F _ {2 3} F _ {3 3} ^ {2} \\\\ f ^ {2} = \\frac {- F _ {1 3} ^ {2} F _ {3 2} F _ {3 3} - F _ {2 3} ^ {2} F _ {3 2} F _ {3 3}}{F _ {1 1} F _ {1 3} F _ {3 1} F _ {3 2} + F _ {2 1} F _ {2 3} F _ {3 1} F _ {3 2} + F _ {1 2} F _ {1 3} F _ {3 2} ^ {2}}. \\tag {5} \\\\ + F _ {2 2} F _ {2 3} F _ {3 2} ^ {2} - F _ {1 2} ^ {2} F _ {3 2} F _ {3 3} - F _ {2 2} ^ {2} F _ {3 2} F _ {3 3} \\\\ - F _ {1 1} F _ {1 2} F _ {3 1} F _ {3 3} - F _ {2 1} F _ {2 2} F _ {3 1} F _ {3 3} \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 524, + 604, + 890, + 688 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "It is well known that the relative motion, $\\mathbf{R}$ and $\\mathbf{t}$ , can be obtained by using a singular value decomposition [11] or a closed-form method [13].", + "bbox": [ + 498, + 696, + 890, + 742 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "If the cameras have a wide angle lens with a radial distortion parameter $k$ , a 2D point $\\mathbf{m}$ is observed as a radially distorted point $\\hat{\\mathbf{m}}$ . The relation can be written by using the division model [10]:", + "bbox": [ + 498, + 743, + 890, + 803 + ], + "page_idx": 1 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {m} = \\frac {1}{1 + k r} \\hat {\\mathbf {m}} \\propto \\left[ \\begin{array}{c} \\hat {u} \\\\ \\hat {v} \\\\ 1 + k r \\end{array} \\right], \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 593, + 811, + 890, + 859 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "where $r = \\hat{u}^2 +\\hat{v}^2$ . Hereafter, we use the hat symbol $\\hat{\\cdot}$ to express radially distorted values.", + "bbox": [ + 498, + 869, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "13362", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "3. Finding F-matrix with known epipoles", + "text_level": 1, + "bbox": [ + 76, + 89, + 421, + 107 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this section, we propose four different algorithms depending on the number of unknown intrinsic parameters and the number of known epipoles. The basic strategy commonly used in all methods is to parameterize a fundamental matrix $\\mathbf{F}$ as a linear combination of the null space of a coefficient matrix computed from epipoles and point correspondences. We reduce the number of unknown variables to one and employ Eq. (4) to lead to a higher-order polynomial equation of the single variable. The fundamental matrix $\\mathbf{F}$ is obtained by substituting the real roots of the polynomial equation into the linear combination of the null space. The null space is derived from the epipoles, and Eq. (4) is used for the root finding, therefore, both the intrinsic and extrinsic parameters can be recovered from the computed $\\mathbf{F}$ .", + "bbox": [ + 75, + 114, + 472, + 327 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. 2-pt algorithm for $\\mathbf{F} + \\mathbf{f}$ with two epipoles", + "text_level": 1, + "bbox": [ + 76, + 335, + 419, + 353 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We start with the simplest case where two epipoles $\\mathbf{e}$ and $\\mathbf{e}'$ are observed by each camera with an unknown focal length $f$ but no lens distortion. If we define the $3 \\times 3$ identity matrix by $\\mathbf{I}$ and a $6 \\times 9$ matrix $\\mathbb{N}_1$ by", + "bbox": [ + 75, + 359, + 468, + 421 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {N} _ {1} = \\left[ \\begin{array}{c c c} \\mathbf {e} ^ {\\mathrm {T}} & & \\\\ & \\mathbf {e} ^ {\\mathrm {T}} & \\\\ & & \\mathbf {e} ^ {\\mathrm {T}} \\\\ x ^ {\\prime} \\mathrm {I} & y ^ {\\prime} \\mathrm {I} & \\mathrm {I} \\end{array} \\right], \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 187, + 429, + 468, + 494 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Eq. (2) can be written in the form", + "bbox": [ + 76, + 505, + 302, + 520 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {N} _ {1} \\mathbf {f} = \\mathbf {0}. \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 238, + 532, + 468, + 547 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Here, $\\mathbb{N}_1$ is of size $6\\times 9$ but its row rank is only five.", + "bbox": [ + 76, + 560, + 426, + 575 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Utilizing two point correspondences, a $8 \\times 9$ coefficient matrix $\\mathbb{M}_1$ is given by", + "bbox": [ + 76, + 575, + 468, + 606 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {M} _ {1} = \\left[ \\begin{array}{c} \\mathrm {N} _ {1} \\\\ \\left(\\mathbf {m} _ {1} ^ {\\prime} \\otimes \\mathbf {m} _ {1}\\right) ^ {\\mathsf {T}} \\\\ \\left(\\mathbf {m} _ {2} ^ {\\prime} \\otimes \\mathbf {m} _ {2}\\right) ^ {\\mathsf {T}} \\end{array} \\right]. \\tag {9}\n$$\n", + "text_format": "latex", + "bbox": [ + 191, + 616, + 468, + 666 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Then, we have", + "bbox": [ + 76, + 676, + 178, + 689 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {M} _ {1} \\mathbf {f} = \\mathbf {0}. \\tag {10}\n$$\n", + "text_format": "latex", + "bbox": [ + 240, + 691, + 468, + 705 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Since the row rank of $\\mathsf{M}_1$ is seven, $\\mathbf{f}$ can be parameterized by a linear combination of two null vectors $\\mathbf{v}_1$ , $\\mathbf{v}_2$ of $\\mathsf{M}_1$ :", + "bbox": [ + 76, + 713, + 468, + 744 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {f} = \\alpha \\mathbf {v} _ {2} + \\mathbf {v} _ {1}. \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 220, + 757, + 468, + 772 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Substituting Eq. (11) into Eq. (4), we obtain a fifth-order equation for the single variable $\\alpha$ , which is represented by", + "bbox": [ + 76, + 784, + 468, + 815 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\nh (\\mathbb {F} (\\alpha)) = c _ {5} \\alpha^ {5} + c _ {4} \\alpha^ {4} + c _ {3} \\alpha^ {3} + c _ {2} \\alpha^ {2} + c _ {1} \\alpha + c _ {0} = 0. \\tag {12}\n$$\n", + "text_format": "latex", + "bbox": [ + 84, + 825, + 468, + 843 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Once we found the roots of Eq. (12), the fundamental matrix $\\mathbf{F}$ is then obtained from Eq. (11). This algorithm gives at most five solutions.", + "bbox": [ + 76, + 854, + 468, + 898 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. 4-pt algorithm for $\\mathbf{F} + \\mathbf{f}$ with single epipole", + "text_level": 1, + "bbox": [ + 500, + 90, + 852, + 107 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "When one of the two epipoles is only available, we can solve the $\\mathbf{F} + f$ problem by adding more two point correspondences. Using four point correspondences together with the single epipole $\\mathbf{e}$ , we can construct a $7 \\times 9$ coefficient matrix $\\mathbb{M}_2$ by", + "bbox": [ + 498, + 114, + 890, + 191 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {M} _ {2} = \\left[ \\begin{array}{c c c} \\mathbf {e} ^ {\\top} & & \\\\ & \\mathbf {e} ^ {\\top} & \\\\ & & \\mathbf {e} ^ {\\top} \\\\ \\left(\\mathbf {m} _ {1} ^ {\\prime} \\otimes \\mathbf {m} _ {1}\\right) ^ {\\top} & & \\\\ & \\vdots & \\\\ \\left(\\mathbf {m} _ {4} ^ {\\prime} \\otimes \\mathbf {m} _ {4}\\right) ^ {\\top} & & \\end{array} \\right], \\tag {13}\n$$\n", + "text_format": "latex", + "bbox": [ + 614, + 205, + 890, + 310 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "which satisfies", + "bbox": [ + 500, + 323, + 601, + 335 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {M} _ {2} \\mathbf {f} = \\mathbf {0}. \\tag {14}\n$$\n", + "text_format": "latex", + "bbox": [ + 661, + 344, + 890, + 359 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The row rank of $\\mathbb{M}_2$ is seven, which is identical to $\\mathbb{M}_1$ . Consequently, we can find $\\mathbb{F}$ using exactly the same approach as in Eqs. (11) and (12). The number of the real solutions of this algorithm is at most five.", + "bbox": [ + 498, + 375, + 890, + 434 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.3. 3-pt algorithm for $\\mathbf{F} + \\mathbf{f} + \\mathbf{k}$ with two epipoles", + "text_level": 1, + "bbox": [ + 500, + 450, + 862, + 467 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "We address a more complicated problem where a radial distortion parameter $k$ is additionally unknown. Since we have two epipoles in this case, this problem can be solved using three point correspondences.", + "bbox": [ + 498, + 474, + 890, + 536 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this problem, the epipoles, $\\hat{\\mathbf{e}}$ and $\\hat{\\mathbf{e}}^{\\prime}$ , are observed in the distorted image coordinates, as with the point correspondences $\\hat{\\mathbf{m}}$ . Using Eq. (6), we can represent the undistorted epipoles, $\\mathbf{e}$ and $\\mathbf{e}^{\\prime}$ , as", + "bbox": [ + 498, + 537, + 890, + 599 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {e} = \\frac {1}{1 + k z} \\hat {\\mathbf {e}} \\propto \\left[ \\begin{array}{c} \\hat {x} \\\\ \\hat {y} \\\\ 1 + k z \\end{array} \\right], \\tag {15}\n$$\n", + "text_format": "latex", + "bbox": [ + 596, + 613, + 890, + 669 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {e} ^ {\\prime} = \\frac {1}{1 + k z ^ {\\prime}} \\hat {\\mathbf {e}} ^ {\\prime} \\propto \\left[ \\begin{array}{c} \\hat {x} ^ {\\prime} \\\\ \\hat {y} ^ {\\prime} \\\\ 1 + k z ^ {\\prime} \\end{array} \\right],\n$$\n", + "text_format": "latex", + "bbox": [ + 594, + 665, + 795, + 712 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $z = \\hat{x}^2 +\\hat{y}^2$ and $z^{\\prime} = \\hat{x}^{\\prime 2} + \\hat{y}^{\\prime 2}$ . Note that the radial distortion $k$ is an unknown parameter.", + "bbox": [ + 500, + 726, + 890, + 758 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Similar to Eqs. (7) and (8), we can rewrite Eq. (2) by", + "bbox": [ + 517, + 760, + 870, + 775 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {N} _ {2} \\mathbf {f} = \\mathbf {0}, \\tag {16}\n$$\n", + "text_format": "latex", + "bbox": [ + 661, + 792, + 890, + 806 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where", + "bbox": [ + 500, + 824, + 545, + 837 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\mathrm {N} _ {2} = \\left[ \\begin{array}{c c c} \\mathbf {e} ^ {\\top} & & \\\\ & \\mathbf {e} ^ {\\top} & \\\\ & & \\mathbf {e} ^ {\\top} \\\\ \\hat {x} ^ {\\prime} \\mathrm {I} & \\hat {y} ^ {\\prime} \\mathrm {I} & (1 + k z ^ {\\prime}) \\mathrm {I} \\end{array} \\right]. \\tag {17}\n$$\n", + "text_format": "latex", + "bbox": [ + 584, + 839, + 890, + 905 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "13363", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "The null space of $\\mathbb{N}_2$ can be symbolically given by", + "bbox": [ + 76, + 90, + 410, + 107 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathsf {V} _ {1} =\n$$\n", + "text_format": "latex", + "bbox": [ + 76, + 119, + 116, + 133 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\left[ \\begin{array}{c c c c} \\hat {y} \\hat {y} ^ {\\prime} & \\hat {y} ^ {\\prime} (1 + k z) & \\hat {y} (1 + k z ^ {\\prime}) & (1 + k z) (1 + k z ^ {\\prime}) \\\\ - \\hat {x} \\hat {y} ^ {\\prime} & 0 & - \\hat {x} (1 + k z ^ {\\prime}) & 0 \\\\ 0 & - \\hat {x} \\hat {y} ^ {\\prime} & 0 & - \\hat {x} (1 + k z ^ {\\prime}) \\\\ - \\hat {x} ^ {\\prime} \\hat {y} & - \\hat {x} ^ {\\prime} (1 + k z) & 0 & 0 \\\\ \\hat {x} \\hat {x} ^ {\\prime} & 0 & 0 & 0 \\\\ 0 & \\hat {x} \\hat {x} ^ {\\prime} & 0 & 0 \\\\ 0 & 0 & - \\hat {x} ^ {\\prime} \\hat {y} & - \\hat {x} ^ {\\prime} (1 + k z) \\\\ 0 & 0 & \\hat {x} \\hat {x} ^ {\\prime} & 0 \\\\ 0 & 0 & 0 & \\hat {x} \\hat {x} ^ {\\prime} \\end{array} \\right] \\tag {18}\n$$\n", + "text_format": "latex", + "bbox": [ + 81, + 136, + 475, + 286 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Thus, the fundamental matrix can be represented as a linear combination of the column vectors of $\\mathrm{V}_1$ , i.e.", + "bbox": [ + 76, + 289, + 468, + 318 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {f} = \\mathrm {V} _ {1} \\boldsymbol {\\alpha} _ {1}, \\tag {19}\n$$\n", + "text_format": "latex", + "bbox": [ + 233, + 330, + 468, + 347 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\alpha_{1}$ is a 4-dim vector.", + "bbox": [ + 76, + 359, + 263, + 373 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We now have three point correspondences, which satisfy $(\\mathbf{m}_i' \\otimes \\mathbf{m}_i)^\\top \\mathbf{f} = 0$ . If we define a $3 \\times 4$ matrix $\\mathsf{G}_1$ by", + "bbox": [ + 76, + 375, + 468, + 405 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {G} _ {1} = \\left[ \\begin{array}{l} \\left(\\mathbf {m} _ {1} ^ {\\prime} \\otimes \\mathbf {m} _ {1}\\right) ^ {\\mathrm {T}} \\\\ \\left(\\mathbf {m} _ {2} ^ {\\prime} \\otimes \\mathbf {m} _ {2}\\right) ^ {\\mathrm {T}} \\\\ \\left(\\mathbf {m} _ {3} ^ {\\prime} \\otimes \\mathbf {m} _ {3}\\right) ^ {\\mathrm {T}} \\end{array} \\right] \\mathrm {V} _ {1}, \\tag {20}\n$$\n", + "text_format": "latex", + "bbox": [ + 184, + 415, + 468, + 464 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "we obtain", + "bbox": [ + 76, + 474, + 147, + 488 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\left[ \\begin{array}{l} \\left(\\mathbf {m} _ {1} ^ {\\prime} \\otimes \\mathbf {m} _ {1}\\right) ^ {\\mathsf {T}} \\\\ \\left(\\mathbf {m} _ {2} ^ {\\prime} \\otimes \\mathbf {m} _ {2}\\right) ^ {\\mathsf {T}} \\\\ \\left(\\mathbf {m} _ {3} ^ {\\prime} \\otimes \\mathbf {m} _ {3}\\right) ^ {\\mathsf {T}} \\end{array} \\right] \\mathbf {f} = \\mathbb {G} _ {1} \\boldsymbol {\\alpha} _ {1} = \\mathbf {0}. \\tag {21}\n$$\n", + "text_format": "latex", + "bbox": [ + 166, + 496, + 468, + 546 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The unknown vector $\\alpha_{1}$ can be determined as the kernel of $\\mathsf{G}_1$ up to scale. Since $\\mathsf{G}_1$ is of size $3\\times 4$ , the kernel can be symbolically computed as a 4-dim vector:", + "bbox": [ + 76, + 556, + 468, + 602 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\boldsymbol {\\alpha} _ {1} \\propto \\operatorname {K e r} \\left(\\mathrm {G} _ {1}\\right) = \\mathrm {Q} _ {1} \\boldsymbol {\\beta} _ {1}, \\tag {22}\n$$\n", + "text_format": "latex", + "bbox": [ + 191, + 614, + 468, + 630 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbb{Q}_1$ is a $4\\times 5$ matrix and $\\beta_{1} = [k^{4},k^{3},k^{2},k,1]^{\\top}$ . We can replace $\\alpha_{1}$ with $\\mathbb{Q}_1\\beta_1$ , then Eq. (19) can be rewritten as", + "bbox": [ + 76, + 641, + 468, + 672 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {f} = \\mathrm {V} _ {1} \\boldsymbol {\\alpha} _ {1} = \\mathrm {V} _ {1} \\mathrm {Q} _ {1} \\boldsymbol {\\beta} _ {1}. \\tag {23}\n$$\n", + "text_format": "latex", + "bbox": [ + 197, + 685, + 468, + 700 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Plugging Eq. (23) into Eq. (4), we finally obtain a 16th-degree polynomial equation in $k$ :", + "bbox": [ + 76, + 712, + 468, + 743 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nh (\\mathbb {F} (k)) = c _ {1 6} k ^ {1 6} + \\dots + c _ {1} k + c _ {0} = 0. \\tag {24}\n$$\n", + "text_format": "latex", + "bbox": [ + 135, + 753, + 468, + 771 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "We can recover $\\mathbf{f}$ by substituting the real roots of Eq. (24) into Eq. (23). This algorithm provides at most 16 real solutions.", + "bbox": [ + 76, + 782, + 468, + 825 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.4. 5-pt algorithm for $\\mathbf{F} + \\mathbf{f} + \\mathbf{k}$ with single epipole", + "text_level": 1, + "bbox": [ + 500, + 90, + 872, + 107 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Given only a single epipole $\\mathbf{e}$ , we need two additional point pairs to solve the $F + f + k$ problem. We omit the details of the derivation and describe the differences only because the procedure of this algorithm is basically similar to Sec. 3.3.", + "bbox": [ + 496, + 113, + 890, + 186 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "The null space of $\\left[ \\begin{array}{ccc}\\mathbf{e}^{\\mathsf{T}} & & \\\\ & \\mathbf{e}^{\\mathsf{T}} & \\\\ & & \\mathbf{e}^{\\mathsf{T}} \\end{array} \\right]$ can be symbolically given by", + "bbox": [ + 496, + 185, + 890, + 246 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nV _ {2} =\n$$\n", + "text_format": "latex", + "bbox": [ + 522, + 258, + 560, + 272 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\left[ \\begin{array}{c c c c c c} - \\hat {y} & 1 + k z & 0 & 0 & 0 & 0 \\\\ \\hat {x} & 0 & 0 & 0 & 0 & 0 \\\\ 0 & - \\hat {x} & 0 & 0 & 0 & 0 \\\\ 0 & 0 & - \\hat {y} & 1 + k z & 0 & 0 \\\\ 0 & 0 & \\hat {x} & 0 & 0 & 0 \\\\ 0 & 0 & 0 & - \\hat {x} & 0 & 0 \\\\ 0 & 0 & 0 & 0 & - \\hat {y} & 1 + k z \\\\ 0 & 0 & 0 & 0 & \\hat {x} & 0 \\\\ 0 & 0 & 0 & 0 & 0 & - \\hat {x} \\end{array} \\right]. \\tag {25}\n$$\n", + "text_format": "latex", + "bbox": [ + 527, + 275, + 890, + 415 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Since $\\mathbf{V}_2$ is of size $9 \\times 6$ , the unknown vector $\\alpha_2$ for this problem becomes a 6-dim vector. Using the five point correspondences, $\\mathsf{G}_2$ is represented as a $5 \\times 6$ matrix, as shown in Eq. (20). Then, we can symbolically obtain the kernel of $\\mathsf{G}_2$ , which is given as the matrix-vector product of a $6 \\times 6$ matrix $\\mathbb{Q}_2$ and $\\beta_2 = [k^5, k^4, k^3, k^2, k, 1]^{\\mathrm{T}}$ . Now we can express the fundamental matrix by", + "bbox": [ + 496, + 424, + 890, + 531 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\n\\mathbf {f} = \\mathrm {V} _ {2} \\mathrm {Q} _ {2} \\beta_ {2}. \\tag {26}\n$$\n", + "text_format": "latex", + "bbox": [ + 650, + 542, + 890, + 559 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Substituting Eq. (26) into Eq. (4), we finally obtain a 21st-order polynomial equation in $k$ , i.e.", + "bbox": [ + 496, + 570, + 890, + 599 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nh (\\mathbb {F} (k)) = c _ {2 1} k ^ {2 1} + \\dots + c _ {1} k + c _ {0} = 0. \\tag {27}\n$$\n", + "text_format": "latex", + "bbox": [ + 557, + 611, + 890, + 628 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Thus, we can obtain at most 21 real solutions.", + "bbox": [ + 500, + 638, + 803, + 652 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.5. Non-linear refinement", + "text_level": 1, + "bbox": [ + 500, + 664, + 705, + 678 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "After running a RANSAC scheme, we generally obtain many inlier points and perform a non-linear refinement to polish the accuracy of the parameters. For example, minimizing the symmetric epipolar distance is one of the major cost functions in the literature [11], i.e.", + "bbox": [ + 496, + 686, + 890, + 763 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nL _ {\\text {s y m}} = \\sum_ {i = 1} ^ {n} \\frac {\\left(\\mathbf {m} _ {i} ^ {\\prime} {} ^ {\\top} \\mathbf {F} \\mathbf {m} _ {i}\\right) ^ {2}}{\\left[ \\mathbf {F} \\mathbf {m} _ {i} \\right] _ {1} ^ {2} + \\left[ \\mathbf {F} \\mathbf {m} _ {i} \\right] _ {2} ^ {2}} + \\frac {\\left(\\mathbf {m} _ {i} ^ {\\prime} {} ^ {\\top} \\mathbf {F} \\mathbf {m} _ {i}\\right) ^ {2}}{\\left[ \\mathbf {F} ^ {\\top} \\mathbf {m} _ {i} ^ {\\prime} \\right] _ {1} ^ {2} + \\left[ \\mathbf {F} ^ {\\top} \\mathbf {m} _ {i} ^ {\\prime} \\right] _ {2} ^ {2}}, \\tag {28}\n$$\n", + "text_format": "latex", + "bbox": [ + 514, + 771, + 890, + 824 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $[\\mathbf{F}\\mathbf{m}_i]_j^2$ denotes the square of the j-th element of the vector $\\mathbf{F}\\mathbf{m}_i$ .", + "bbox": [ + 496, + 825, + 890, + 854 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Since we have an initial guess of the focal length of the two images as $f_{1} = f_{2} = f$ , we can parameterize the fundamental matrix by $\\mathbf{F} = \\mathrm{diag}(1,1,f_2)\\mathbf{E}\\mathrm{diag}(1,1,f_1)$", + "bbox": [ + 496, + 854, + 890, + 901 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "13364", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathbf{E}$ represents an essential matrix. Thus, we can use the Helmke's method [12] to update $\\mathbf{E}$ with preserving 5 DoFs. Also, we initialize the lens distortion of the two images by $k_{1} = k_{2} = k$ .", + "bbox": [ + 76, + 90, + 467, + 151 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "However, those typical approaches of the non-linear refinement do not assume that epipoles are known, which in turn may degrade the fundamental matrix obtained by the proposed method. To avoid this issue, we introduce a regularization term of Eq. (2) as follows:", + "bbox": [ + 76, + 154, + 467, + 231 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nL _ {\\mathrm {e p i}} = \\left\\| \\mathbf {F} \\mathbf {e} \\right\\| ^ {2} + \\left\\| \\mathbf {F} ^ {\\mathsf {T}} \\mathbf {e} ^ {\\prime} \\right\\| ^ {2}. \\tag {29}\n$$\n", + "text_format": "latex", + "bbox": [ + 181, + 244, + 467, + 267 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Note that the epipoles, $\\mathbf{e}$ and $\\mathbf{e}^{\\prime}$ , are undistorted using Eq. (15) with $k_{1}$ and $k_{2}$ . In the case of the single epipole, the second term $\\left\\| \\mathbf{F}^{\\mathsf{T}}\\mathbf{e}^{\\prime}\\right\\|^{2}$ is simply dropped.", + "bbox": [ + 76, + 281, + 467, + 330 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The total cost function of the proposed scheme is given by jointly optimizing $L_{\\mathrm{sym}}$ and $L_{\\mathrm{epi}}$ with a weight $w$ :", + "bbox": [ + 76, + 330, + 467, + 363 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nL = L _ {\\text {s y m}} + w L _ {\\text {e p i}}. \\tag {30}\n$$\n", + "text_format": "latex", + "bbox": [ + 202, + 378, + 467, + 396 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "4. Degenerate configurations", + "text_level": 1, + "bbox": [ + 76, + 415, + 320, + 431 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Analysis of the degenerate configurations is important to avoid ambiguous 3D shape reconstructions and use the proposed method in real applications. Due to limitations of space, we give several simple examples for $\\mathbf{F} + f$ problem with two known epipoles in this section.", + "bbox": [ + 76, + 441, + 467, + 518 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Degenerate configurations of two-view geometry in general cases have been extensively studied for the past decades [5, 17, 33, 35]. One typical situation that could often occur in practice is forward motion, where both focal length and radial distortion cannot be uniquely determined regardless of the point distributions. Forward motion alone is not the case for the proposed solvers, but forward motion with special point distributions is. One configuration where the proposed 2-point solver for $\\mathbf{F} + f$ problem cannot be solved is that two epipoles and two point correspondences are collinear under forward motion. For example, the row rank of $\\mathbb{M}_1$ is less than seven in Eq. (9) when $\\mathbf{e} = \\mathbf{e}' = [0,0,1]^{\\mathrm{T}}$ , $\\mathbf{m}_i = [u_i,0,1]^{\\mathrm{T}}$ , $\\mathbf{m}_i' = [-u_i,0,1]^{\\mathrm{T}}$ , $i \\in \\{1,2\\}$ . Another well-known degenerate configuration for the general solvers is that all 3D points are on a plane. However, in our case, unique solutions can be obtained in planar scenes when two epipoles are known [30].", + "bbox": [ + 76, + 521, + 467, + 777 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "The rigorous conditions can be given by analyzing the rank of submatrices of $\\mathbb{N}_1$ and $\\mathbb{M}_1$ ( $\\mathbb{N}_2$ and $\\mathbb{M}_2$ for the other problems as well). In other words, we first find epipoles and image points that cause rank deficiency, then link them to actual camera motions and 3D point distributions. However, as reported in the previous studies, it is not easy to reveal all possible ambiguities. We would leave the in-depth discussion to future research.", + "bbox": [ + 75, + 780, + 467, + 898 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5. Experiments", + "text_level": 1, + "bbox": [ + 500, + 90, + 632, + 107 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "This section reports experimental results on synthetic and real data. We conducted all experiments on a PC with Core i7-13700k.", + "bbox": [ + 498, + 114, + 890, + 159 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.1. Implementation", + "text_level": 1, + "bbox": [ + 500, + 167, + 658, + 185 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We have implemented five conventional methods and the four proposed methods in MATLAB, as shown in Tab. 1. We chose three Gröbner basis solvers that are the state-of-the-art based on the efficient parameterization (Eq. (4)): Larsson's 6-point solver for $\\mathrm{F} + f$ problem (L6f) [21], Larsson's 7-point solver for $\\mathrm{F} + f + k$ problem (L7fk) [21], and Martyushev's 7-point solver for $\\mathrm{F} + f + k$ problem (M7fk) [24]. Those are designed for general scenes, therefore, epipoles are not assumed to be available. Moreover, we used two DLT-based approaches by Ito et al. [14]: the 3-point solver with two epipoles (I3), and the 5-point solver with a single epipole (I5). Although I3 and I5 do not guarantee to satisfy Eq. (3) or Eq. (4), we calculated focal length by simply applying Eq. (5) to a fundamental matrix given by I3 or I5. We used the root function for solving the polynomials of the proposed solvers, i.e. Eqs. (12), (24) and (27).", + "bbox": [ + 498, + 191, + 890, + 434 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.2. Evaluation metrics", + "text_level": 1, + "bbox": [ + 500, + 441, + 681, + 455 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We measured the following metrics to quantitatively evaluate the estimation accuracy:", + "bbox": [ + 500, + 465, + 890, + 496 + ], + "page_idx": 4 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "$\\epsilon_{\\mathrm{F}}$ Symmetric epipolar distance in pixels by applying $\\mathbf{F}_{\\mathrm{est}}$ onto the ground-truth 2D points.", + "$\\epsilon_{f}$ Relative error by $|f_{\\mathrm{est}} - f_{\\mathrm{gt}}| / f_{\\mathrm{gt}} \\times 100[\\%]$ .", + "$\\epsilon_{k}$ Normalized pixel distance $[\\%]$ between undistorted coordinates using $k_{\\mathrm{est}}$ and $k_{\\mathrm{gt}}$ . 100 points were uniformly sampled, and the mean distance is normalized by the diagonal length of the image.", + "$\\epsilon_{\\mathrm{R}}$ Angle-axis error by $\\cos^{-1}\\left(\\frac{\\operatorname{tr}(\\mathbb{R}_{\\mathrm{gt}}^{\\mathrm{T}}\\mathbb{R}_{\\mathrm{est}}) - 1}{2}\\right)$ [degrees].", + "$\\epsilon_{t}$ Cosine similarity by $\\cos^{-1}\\left(\\frac{\\mathbf{t}_{\\mathrm{gt}}^{\\mathrm{T}}\\mathbf{t}_{\\mathrm{est}}}{\\|\\mathbf{t}_{\\mathrm{gt}}\\| \\|\\mathbf{t}_{\\mathrm{est}}\\|}\\right)$ [degrees]." + ], + "bbox": [ + 500, + 503, + 890, + 709 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.3. Synthetic data", + "text_level": 1, + "bbox": [ + 500, + 714, + 645, + 729 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We investigate the performance of the minimal solvers using synthetic data in this section.", + "bbox": [ + 500, + 738, + 888, + 768 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "5.3.1 Scene configuration", + "text_level": 1, + "bbox": [ + 500, + 786, + 691, + 801 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "We created synthetic scenes as follows. Two cameras were randomly located in the area of $5.0\\mathrm{m}\\times 5.0\\mathrm{m}$ and $2.0\\mathrm{m}$ high to project each other, as shown in Fig. 1b. Small perturbations within 5 degrees and $\\pm 0.2\\mathrm{m}$ were added to the rotation and position of the cameras, respectively. The image resolution was $640\\times 480$ , the focal length was set to", + "bbox": [ + 498, + 810, + 890, + 900 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "13365", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/681b22d96a494fd21dfcd2f913f0dcf337a83fd2a24bbf5f677bd96a4a9e1b3e.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodReferenceProblemDecomposability Eqs. (3) and (4)# of points# of epipoles# of solutionsApproach
L6f[21]F+f✓6015
L7fk[21]F+f+k✓7068Gröbner basis
M7fk[24]F+f+k✓7068
I5[14]F511DLT
I3[14]F321
P4fF+f✓415
P2fF+f✓225Closed-form
P5fkF+f+k✓5116
P3fkF+f+k✓3221
", + "bbox": [ + 96, + 88, + 874, + 282 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Table 1. Methods compared in the experiments.", + "bbox": [ + 341, + 281, + 624, + 295 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/9fb1f99234204473fd039bf3db6b315f9e155a40cf1bc2de96ddd8f77bc55523.jpg", + "image_caption": [ + "Figure 3. The cumulative histogram of numerical accuracy for $10^{6}$ trials of randomly generated data without noise." + ], + "image_footnote": [], + "bbox": [ + 80, + 308, + 310, + 449 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/7b9d7b60b7cd00909793ab8489f37ca8baf342f81e985ef7e73f1f5c20a6f788.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 328, + 308, + 555, + 449 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/7b19aa2cc71430f02437ba66449302d9c80a36623cf6ac7d1d9c9aa4722a2418.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 573, + 309, + 888, + 450 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "$f = 381.3$ , which is approximately $80^{\\circ}$ HFOV. The radial lens distortion was set to $k = -0.2 / f^{2}$ for the $\\mathsf{F} + f + k$ problem. We uniformly generated 100 3D points in the common viewing frustum of the two cameras and projected the 3D points onto the image plane. Then, we randomly picked the minimal number of the points needed for each method.", + "bbox": [ + 75, + 493, + 468, + 599 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.3.2 Numerical stability", + "text_level": 1, + "bbox": [ + 76, + 619, + 264, + 635 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In the first test, we investigated the numerical stability of the methods in noise free data. Figure 3 summarizes a cumulative histogram of $\\epsilon_{\\mathrm{F}}, \\epsilon_{f}$ , and $\\epsilon_{k}$ over $10^{6}$ independent trials. The figure indicates that the proposed methods are numerically stable. Comparing the methods in each categories, we see that P2f and P4f are better than I3, I5, and L6f in the $\\mathbf{F} + f$ problem, and P5fk and P3fk are better than L7fk and M7fk in the $\\mathbf{F} + f + k$ problem. Here, it should be noted that L7fk is so unstable as to be impractical. We further investigate this issue in the following experiments.", + "bbox": [ + 75, + 643, + 470, + 796 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.3.3 Robustness w.r.t. noise on points", + "text_level": 1, + "bbox": [ + 76, + 816, + 354, + 830 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To evaluate the robustness against the image noise, we measured the estimation errors by adding the zero-mean Gaussian noise onto point correspondences with the standard deviation $0 \\leq \\sigma \\leq 2$ pixels. In this experiment, the image", + "bbox": [ + 75, + 839, + 470, + 902 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "noise was not added to the epipoles, that is, the ground-truth values are given for the epipoles. Figure 4 shows the mean error over $10^{5}$ independent trials for each noise level. From the figure, we see that the proposed methods are the most robust against noise. Since the two DLT methods, I3 and I5, do not consider the decomposability conditions described in Eqs. (3) and (4), their focal length estimation are sensitive to image noise, which is even worse than the general methods, L6f and M7fk. The proposed methods outperform M7fk in estimation of the fundamental matrix and lens distortion while showing comparable accuracy in the focal length estimation.", + "bbox": [ + 496, + 493, + 890, + 676 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "5.3.4 Robustness w.r.t. noise on epipoles", + "text_level": 1, + "bbox": [ + 500, + 729, + 790, + 744 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "In this experiment, we studied the noise robustness of the six methods using epipoles: two Ito et al.'s and four proposed methods. We added the Gaussian noise on epipoles varying $0 \\leq \\sigma \\leq 2$ while fixing the image noise as $\\sigma = 0.5$ . Figure 5 reports the mean error over $10^{5}$ independent trials for each noise level. The results have similar trends to the previous experiments. Among the proposed methods, P4f and P5fk are more robust to image noise than P2f and P4fk because P4f and P5fk utilizes a single epipole.", + "bbox": [ + 496, + 763, + 890, + 902 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "13366", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/99d89e7e4e9c19cc85c907b3c7ce54016915323b0cd28dfc4f8751582260d8cb.jpg", + "image_caption": [ + "Figure 4. Mean error w.r.t. the image noise on point correspondences over $10^{5}$ trials for each noise level." + ], + "image_footnote": [], + "bbox": [ + 81, + 89, + 305, + 229 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/8994edff9cdb188bdb4eead015c6c09392db192299040990fea3b24d80fb3968.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 326, + 89, + 553, + 229 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/5664e932849efbcaf2d8da12b48902f98a13f6b517becc20edfe424d1dd1a4cd.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 573, + 90, + 887, + 229 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/e134de50c0baa8f25103f622cd72d2c8c5c4238a3ce5843b6563dff8b1c47985.jpg", + "image_caption": [ + "Figure 5. Mean error w.r.t. the image noise on epipoles over $10^{5}$ trials for each noise level." + ], + "image_footnote": [], + "bbox": [ + 81, + 263, + 305, + 402 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c8c3686f14bef2207ce398bbb387a47f3fd74aa8ad9fec61e00fdbdd1527d04e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 326, + 263, + 552, + 402 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/9c6e1916cbd1677671060efe4a8d3bd5571cf855bf3175d5e89b6e2380cbc5ce.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 573, + 263, + 887, + 402 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/37b9b09e447e426ed17aecde9705a56f68734e27eacc23d5270077a0ef260501.jpg", + "image_caption": [ + "Figure 6. Runtime comparison of the minimal solvers." + ], + "image_footnote": [], + "bbox": [ + 112, + 450, + 439, + 609 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.3.5 Computational time", + "text_level": 1, + "bbox": [ + 76, + 665, + 271, + 680 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Figure 6 shows the mean runtime of all methods over $10^{6}$ independent trials. The computational time of the proposed methods is less than 1 msec, which is not as fast as the Ito et al.'s methods, but is still reasonably fast enough for real-time applications.", + "bbox": [ + 75, + 696, + 468, + 773 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.4. Real data", + "text_level": 1, + "bbox": [ + 76, + 796, + 187, + 811 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "In this experiments, we incorporated each method into RANSAC together with the non-linear refinement to investigate the performance in real data. We excluded L7fk due to its instability and high computational cost shown in the synthetic data experiments in Sec. 5.3.", + "bbox": [ + 75, + 824, + 468, + 902 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "5.4.1 Dataset", + "text_level": 1, + "bbox": [ + 500, + 446, + 607, + 460 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We used two publicly available dataset where multiple cameras are mutually projected:", + "bbox": [ + 498, + 470, + 890, + 502 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "HumanEva [32] Four RGB cameras with the $656 \\times 490$ resolution are installed in the corners of a room. The intrinsic parameters are calibrated by Zhang's method, then the extrinsics are calculated using Vicon sensors. A single person is asked to do simple actions such as walking, jogging, etc. There are two combinations of mutual camera projections with two epipoles.", + "bbox": [ + 500, + 506, + 892, + 613 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Panoptic studio $[16]^{2}$ 30 HD cameras, 480 VGA cameras, and 5 Kinect2 are installed on the walls of a domeshaped studio. Both the intrinsic and extrinsic parameters of all cameras are simultaneously calibrated based on the structure-from-motion. All sensors are used for recording multi-person interactions. There are 20 combinations of a single epipole and 80 combinations of two epipoles in the HD cameras.", + "bbox": [ + 500, + 619, + 890, + 742 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "We chose a video sequence from each dataset in which a single person moves around the scene: S2 sequence of HumanEva (Fig. 2a) and dance1 of Panoptic studio (Fig. 2b). Then, 2D human joints on the video frames were detected using OpenPose [7]. The neck and hip joints were selected as the point correspondences because they are less likely to be occluded and are easily observed from any camera. We manually labeled epipole locations in each image.", + "bbox": [ + 496, + 746, + 893, + 868 + ], + "page_idx": 6 + }, + { + "type": "page_footnote", + "text": "1http://humaneva.is.tue.mpg.de/", + "bbox": [ + 514, + 875, + 763, + 887 + ], + "page_idx": 6 + }, + { + "type": "page_footnote", + "text": "$^{2}$ http://domedb.perception.cs.cmu.edu/", + "bbox": [ + 514, + 887, + 808, + 898 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "13367", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "table", + "img_path": "images/058d486d42b34de5c5f0fbd9be9d6476fe8f92ff226faff41a6387773209a85d.jpg", + "table_caption": [], + "table_footnote": [], + "table_body": "
MethodεRεtεfεkiter.time
L6f28.014.348.80.7812410.25
M7fk29.815.156.11.4628197.69
I332.816.170.00.26920.04
P2f22.711.348.00.26390.03
P3fk24.712.346.91.111460.04
", + "bbox": [ + 89, + 88, + 457, + 195 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/e3fce761d315c29ca8c430cf1af8eb002ee8a23d9de3ed97106a205e6c1e9111.jpg", + "table_caption": [ + "(a) HumanEva: S2 (2 epipoles, 2 sequences)" + ], + "table_footnote": [], + "table_body": "
MethodεRεtεfεkiter.time
L6f17.38.518.62.70100002.68
M7fk23.812.219.82.611000033.43
I515.512.430.72.69100000.83
P4f11.36.818.02.68100001.22
P5fk11.26.518.22.09100003.64
", + "bbox": [ + 83, + 215, + 464, + 323 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/55071caaedd56753c28fdfaff416befc70d892ce4cde0b830ab414ce2ff86606.jpg", + "table_caption": [ + "(b) Panoptic studio: dance1 (single epipole, 20 sequences)" + ], + "table_footnote": [], + "table_body": "
MethodεRεtεfεkiter.time
L6f10.34.919.82.67100001.80
M7fk12.05.920.02.851000024.88
I313.18.033.72.6620010.15
P2f6.12.817.72.663180.04
P3fk6.63.217.91.7224380.40
", + "bbox": [ + 84, + 343, + 460, + 450 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "(c) Panoptic studio: dance1 (2 epipoles, 80 sequences)", + "bbox": [ + 104, + 455, + 441, + 470 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 2. Quantitative results of real image dataset (best in bold and second-best underlined). iter.: the number of RANSAC iterations, time: the total processing time of RANSAC and the non-linear refinement in seconds.", + "bbox": [ + 75, + 473, + 468, + 527 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4.2 Quantitative results", + "text_level": 1, + "bbox": [ + 76, + 555, + 269, + 570 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "For testing the methods, we configured RANSAC to have the threshold by 3 pixels, the confidence by 0.995, and the maximum iteration number by 10000. The random seed was fixed for all methods during a single trial so that the same sample points were drawn. After RANSAC, the nonlinear refinement described in Sec. 3.5 was performed on inliers to polish the camera parameters to be more accurate. The two general solvers, L6f and M7fk, optimized only the symmetric epipolar distance $L_{\\mathrm{sym}}$ in Eq. (29). The rest of the solvers utilizing epipoles employed the total cost function $L$ in Eq. (30) with a weight $w = 100 \\times n$ to balance $L_{\\mathrm{sym}}$ and $L_{\\mathrm{epi}}$ depending on the number of the points $n$ .", + "bbox": [ + 75, + 580, + 468, + 763 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "We conducted 100 and 10 trials for each camera pair of S2 and dance1, respectively. Table 2 reports the average values of $(\\epsilon_{\\mathrm{R}}, \\epsilon_{\\mathrm{t}}, \\epsilon_{f}, \\epsilon_{k})$ , the number of RANSAC iterations, and the total processing time. Comparing Tab. 2a with Tabs. 2b and 2c, we can see that all methods show better scores in dance1 even though two epipoles are available in HumanEva. The person in dance1 is captured in the higher-resolution image than in HumanEva, resulting in higher localization accuracy of the 2D joints.", + "bbox": [ + 75, + 763, + 470, + 901 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/eab72c54270ee1c7cf3c1042e6202a103a6cb67b5e6628fe70e5afa33198b371.jpg", + "image_caption": [ + "(a) 2D trajectory of the neck." + ], + "image_footnote": [], + "bbox": [ + 501, + 88, + 679, + 191 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/34e72345ef89d82a5ba98e1bbaee4f543903960e2164db9af423de8e0e9906c4.jpg", + "image_caption": [ + "(c) Top view." + ], + "image_footnote": [], + "bbox": [ + 545, + 224, + 630, + 320 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/de3e95baf29bedc7e13f0be7e36770923b4097aa2e1db6338a8e270fda81706f.jpg", + "image_caption": [ + "(b) Reprojection of estimated epipoles (green area in (a))." + ], + "image_footnote": [], + "bbox": [ + 712, + 89, + 890, + 191 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/4f623994e9868250f22ba0fcd19dc84ad86aeb283cbbcb9834260287631dd827.jpg", + "image_caption": [ + "(d) Side view.", + "Figure 7. 3D shape reconstruction of HumanEva S2." + ], + "image_footnote": [], + "bbox": [ + 702, + 233, + 887, + 321 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/cbd587f7e36a92494e271d6f4e5be12527e304a2c8a11ff860416dad8155677e.jpg", + "image_caption": [ + "(a) 2D trajectory of the neck." + ], + "image_footnote": [], + "bbox": [ + 501, + 380, + 679, + 458 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/0d01220f421f53ae428a3f1e3ec2583b4d14c84f3580a7cb11ea2f11892e9d2e.jpg", + "image_caption": [ + "(b) Reprojection of estimated epipoles. (green area in (a))" + ], + "image_footnote": [], + "bbox": [ + 712, + 380, + 890, + 459 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/d99c605f1a38e79a23dc15a6752f6e44a8bc6d88f22e50b048e8b15ed42f5a52.jpg", + "image_caption": [ + "(c) Top view.", + "Figure 8. 3D shape reconstruction of Panoptic studio dance1." + ], + "image_footnote": [], + "bbox": [ + 521, + 492, + 661, + 601 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/7462b572e50d9be3959d830517ad7df6bb8798d9e85f74624f2eecac46143d36.jpg", + "image_caption": [ + "(d) Side view." + ], + "image_footnote": [], + "bbox": [ + 715, + 508, + 888, + 601 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Table 2 indicates that the proposed solvers outperform the conventional methods in either case of one or two epipoles. The proposed solvers show the best or the second-best scores in most evaluation criteria. For example, P2f and P4f are more than 100 times faster than M7fk while achieving lower estimation errors. Although P2f and P4f does not estimate the radial distortion $k$ in RANSAC, the non-linear refinement successfully converges to an accurate solution of $k$ due to a good initial guess of $\\mathbf{F}$ and $\\mathbf{f}$ . On the other hand, in spite of the use of epipoles, I3 and I5 are inferior to the general solvers L6f and M7fk. As reported in Sec. 5.3, two Ito's methods are sensitive to image noise. According to the above observations, we can conclude that satisfying the decomposability conditions, Eqs. (3) and (4), significantly improves the estimation accuracy even with known epipoles.", + "bbox": [ + 496, + 672, + 890, + 901 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "13368", + "bbox": [ + 480, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5.4.3 Qualitative results", + "text_level": 1, + "bbox": [ + 76, + 90, + 261, + 107 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Figures 7 and 8 visualize a 3D shape reconstruction of S2 and dance1, respectively. For ease of viewing, only neck joints are shown in both 2D and 3D images. We plotted the position of estimated epipoles over 30 independent trials in Figs. 7b and 8b. The P3fk's epipole and the ground-truth overlap so closely that the difference is not visible. On the other hand, the camera motion given by M7fk has large errors and the epipole is estimated on a different place in each trial. This is consistent with the result in Tab. 2 where the proposed methods have the smallest motion errors. Also, we can visually validate that P3fk reconstructs a 3D shape more accurately than M7fk in Figs. 7c, 7d, 8c and 8d.", + "bbox": [ + 75, + 114, + 472, + 297 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "6. Limitations and future work", + "text_level": 1, + "bbox": [ + 76, + 308, + 341, + 324 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "One of the limitations is that epipole positions are manually annotated. This is not a critical issue in data set creation (Figs. 2a and 2b) because device installations and data capturing spend time dominantly. However, a fast-automatic epipole detector is required to use the proposed method in real-time applications such as multi-agent Visual-SLAM [28, 29, 36] shown in Figs. 2c and 2d. Although direct epipole estimation has been studied for several decades [2, 8, 22], unfortunately it cannot be said as active nor extensive. We think that the manual labeling is merely a current limitation, which can be resolved by future effort in the computer vision community. For instance, a quick workaround is to place a camera at the center of a colored sphere or circle and detect the camera's center in images by ellipse fitting. Alternatively, there are more sophisticated ways that use wifi/radio waves or IMUs to find the relative locations between devices in 3D space [3].", + "bbox": [ + 75, + 333, + 472, + 589 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "Another future work is to extend the proposed approach to multi-view geometry, just as Sato [30] extended Ito et al.'s DLT method [14] for obtaining a trifocal or quadrifocal tensor. Combining the multi-view extension with an automatic epipole detector, we can expect that the proposed approach stabilizes multi-agent Visual-SLAM with wide baselines for large-scale scene.", + "bbox": [ + 75, + 590, + 472, + 696 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "7. Conclusion", + "text_level": 1, + "bbox": [ + 76, + 709, + 194, + 724 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "We have presented four minimal solutions to the uncalibrated two-view geometry where one or two epipoles are visible in the image plane. All solvers are manually formulated as higher-order polynomials in a single variable without an automatic Gröbner basis generator. We briefly discussed the degenerate conditions and showed several examples where the proposed solvers are feasible but not the conventional methods. In the experiments, we first compared the proposed solvers with the conventional methods in the numerical stability and robustness against image noise using synthetic data. Then, we demonstrated that the proposed", + "bbox": [ + 75, + 734, + 472, + 902 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "solvers successfully stabilize the structure-from-motion using human joints as point correspondences, which are noisy and less accurate than image feature points. Through these experiments, the proposed solvers outperform the conventional methods in estimation accuracy with maintaining computational efficiency. Finally, we discussed the current limitations of the proposed approach and future work to be applicable in real-time applications. We hope this paper will motivate the computer vision community to develop automatic epipole detectors more extensively.", + "bbox": [ + 496, + 90, + 893, + 243 + ], + "page_idx": 8 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 500, + 255, + 596, + 271 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Sameer Agarwal, Yasutaka Furukawa, Noah Snavely, Ian Simon, Brian Curless, Steven M Seitz, and Richard Szeliski. Building rome in a day. Communications of the ACM, 54(10):105-112, 2011. 1", + "[2] Farhoosh Alghabi and Mohsen Soryani. Direct computation of epipoles using two pairs of point-line correspondences. In 2008 Second International Symposium on Intelligent Information Technology Application, volume 3, pages 486-489, 2008. 9", + "[3] Safar M Asaad and Halgurd S Maghdid. A comprehensive review of indoor/outdoor localization solutions in IoT era: Research challenges and future perspectives. Computer Networks, page 109041, 2022. 9", + "[4] Shai Avidan and Amnon Shashua. Novel view synthesis in tensor space. In Proceedings of IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 1034-1040. IEEE, 1997. 1", + "[5] GN Newsam DQ Huynh MJ Brooks and HP Pan. Recovering unknown focal lengths in self-calibration: An essentially linear algorithm and degenerate configurations. In Proc. ISPRS-Congress, volume 31, pages 575-580. Citeseer, 1996. 5", + "[6] Cesar Cadena, Luca Carlone, Henry Carrillo, Yasir Latif, Davide Scaramuzza, José Neira, Ian Reid, and John J Leonard. Past, present, and future of simultaneous localization and mapping: Toward the robust-perception age. IEEE Transactions on robotics, 32(6):1309-1332, 2016. 1", + "[7] Z. Cao, G. Hidalgo Martinez, T. Simon, S. Wei, and Y. A. Sheikh. Openpose: Realtime multi-person 2d pose estimation using part affinity fields. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2019. 7", + "[8] Huiqin Chen, Emanuel Aldea, and Sylvie Le Hégarat-Mascle. Determining epipole location integrity by multimodal sampling. In 2019 16th IEEE International Conference on Advanced Video and Signal Based Surveillance (AVSS), pages 1-8. IEEE, 2019. 9", + "[9] Martin A Fischler and Robert C Bolles. Random sample consensus: a paradigm for model fitting with applications to image analysis and automated cartography. Communications of the ACM, 24(6):381-395, 1981. 1", + "[10] Andrew W Fitzgibbon. Simultaneous linear estimation of multiple view geometry and lens distortion. In Proceedings of the 2001 IEEE Computer Society Conference on Computer Vision and Pattern Recognition. CVPR 2001, volume 1, pages I-I. IEEE, 2001. 2" + ], + "bbox": [ + 501, + 279, + 893, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "13369", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[11] Richard I. Hartley and Andrew Zisserman. Multiple View Geometry in Computer Vision. Cambridge University Press, ISBN: 0521540518, second edition, 2004. 1, 2, 4", + "[12] Uwe Helmke, Knut Hüper, Pei Yean Lee, and John Moore. Essential matrix estimation using gauss-newton iterations on a manifold. International Journal of Computer Vision, 74(2):117-136, 2007. 5", + "[13] Berthold KP Horn. Recovering baseline and orientation from essential matrix. J. Opt. Soc. Am, 110, 1990. 2", + "[14] M. Ito, T. Sugimura, and J. Sato. Recovering structures and motions from mutual projection of cameras. In 2002 International Conference on Pattern Recognition, volume 3, pages 676-679 vol.3, 2002. 1, 5, 6, 9", + "[15] Fangyuan Jiang, Yubin Kuang, Jan Erik Solem, and Kalle Åström. A minimal solution to relative pose with unknown focal length and radial distortion. In Asian Conference on Computer Vision, pages 443-456. Springer, 2014. 1", + "[16] Hanbyul Joo, Hao Liu, Lei Tan, Lin Gui, Bart Nabbe, Iain Matthews, Takeo Kanade, Shohei Nobuhara, and Yaser Sheikh. Panoptic studio: A massively multiview system for social motion capture. In Proceedings of the IEEE International Conference on Computer Vision, pages 3334-3342, 2015. 2, 7", + "[17] Kenichi Kanatani and Chikara Matsunaga. Closed-form expression for focal lengths from the fundamental matrix. In Proc. 4th Asian Conf. Comput. Vision, volume 1, pages 128-133. CiteSeer, 2000. 5", + "[18] Yubin Kuang, Jan E Solem, Fredrik Kahl, and Kalle Astrom. Minimal solvers for relative pose with a single unknown radial distortion. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 33-40, 2014. 1", + "[19] Zuzana Kukelova, Martin Bujnak, and Tomas Pajdla. Polynomial eigenvalue solutions to the 5-pt and 6-pt relative pose problems. In Proceedings of the British Machine Vision Conference, pages 56.1-56.10. BMVA Press, 2008. doi:10.5244/C.22.56.1", + "[20] Zuzana Kukelova, Joe Kileel, Bernd Sturmfels, and Tomas Pajdla. A clever elimination strategy for efficient minimal solvers. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4912-4921, 2017. 2", + "[21] Viktor Larsson, Kalle Astrom, and Magnus Oskarsson. Efficient solvers for minimal problems by syzygy-based reduction. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 820-829, 2017. 1, 5, 6", + "[22] Jonathan Lawn and Roberto Cipolla. Epipole estimation using affine motion parallax. In Proceedings of the British Machine Vision Conference, pages 38.1-38.10. BMVA Press, 1993. doi:10.5244/C.7.38.9", + "[23] Hongdong Li. A simple solution to the six-point two-view focal-length problem. In European Conference on Computer Vision, pages 200-213. Springer, 2006. 1", + "[24] Evgeniy Martyushev, Jana Vrablikova, and Tomas Pajdla. Optimizing elimination templates by greedy parameter search. In Proceedings of the IEEE/CVF Conference" + ], + "bbox": [ + 78, + 90, + 468, + 900 + ], + "page_idx": 9 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "on Computer Vision and Pattern Recognition, pages 15754-15764, 2022. 5, 6", + "[25] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. In European conference on computer vision, pages 405-421. Springer, 2020. 1", + "[26] Raul Mur-Artal, Jose Maria Martinez Montiel, and Juan D Tardos. Orb-slam: a versatile and accurate monocular slam system. IEEE transactions on robotics, 31(5):1147-1163, 2015. 1", + "[27] David Nister and Frederik Schaffalitzky. Four points in two or three calibrated views: Theory and practice. International Journal of Computer Vision, 67:211-231, 2006. 1", + "[28] Jacob M Perron, Rui Huang, Jack Thomas, Lingkang Zhang, Ping Tan, and Richard T Vaughan. Orbiting a moving target with multi-robot collaborative visual slam. In Proceedings of the Workshop on Multi-View Geometry in Robotics (MVI-GRO), Rome, Italy, pages 1339–1344, 2015. 2, 9", + "[29] Thomas Pollok and Eduardo Monari. A visual slam-based approach for calibration of distributed camera networks. In 2016 13th IEEE International Conference on Advanced Video and Signal Based Surveillance (AVSS), pages 429-437, 2016. 2, 9", + "[30] Jun Sato. Recovering multiple view geometry from mutual projections of multiple cameras. International Journal of Computer Vision, 66(2):123-140, 2006. 1, 5, 9", + "[31] Johannes Lutz Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In Conference on Computer Vision and Pattern Recognition (CVPR), 2016. 1", + "[32] Leonid Sigal, Alexandru O Balan, and Michael J Black. Humaneva: Synchronized video and motion capture dataset and baseline algorithm for evaluation of articulated human motion. International journal of computer vision, 87(1):4-27, 2010. 2, 7", + "[33] Carsten Steger. Estimating the fundamental matrix under pure translation and radial distortion. ISPRS Journal of Photogrammetry and Remote Sensing, 74:202-217, 2012. 5", + "[34] Henrik Stewénius, David Nister, Fredrik Kahl, and Frederik Schaffalitzky. A minimal solution for relative pose with unknown focal length. Image and Vision Computing, 26(7):871-877, 2008. 1", + "[35] Changchang Wu. Critical configurations for radial distortion self-calibration. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 25-32, 2014. 5", + "[36] Danping Zou and Ping Tan. Coslam: Collaborative visual slam in dynamic environments. IEEE Transactions on Pattern Analysis and Machine Intelligence, 35(2):354-366, 2013. 2, 9" + ], + "bbox": [ + 501, + 92, + 890, + 797 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "13370", + "bbox": [ + 480, + 944, + 519, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/1ff0de2c-2b50-437f-a3e0-afb03703f817_model.json b/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/1ff0de2c-2b50-437f-a3e0-afb03703f817_model.json new file mode 100644 index 0000000000000000000000000000000000000000..d90da3aa2541233fbeb1251af50b9c8b1dee154c --- /dev/null +++ b/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/1ff0de2c-2b50-437f-a3e0-afb03703f817_model.json @@ -0,0 +1,2904 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.807, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.096, + 0.131, + 0.877, + 0.155 + ], + "angle": 0, + "content": "Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles" + }, + { + "type": "text", + "bbox": [ + 0.428, + 0.182, + 0.543, + 0.198 + ], + "angle": 0, + "content": "Gaku Nakano" + }, + { + "type": "text", + "bbox": [ + 0.414, + 0.2, + 0.558, + 0.217 + ], + "angle": 0, + "content": "NEC Corporation" + }, + { + "type": "text", + "bbox": [ + 0.337, + 0.217, + 0.636, + 0.235 + ], + "angle": 0, + "content": "1753 Shimonumabe, Kawasaki, Japan" + }, + { + "type": "text", + "bbox": [ + 0.413, + 0.238, + 0.559, + 0.251 + ], + "angle": 0, + "content": "g-nakano@nec.com" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.287, + 0.314, + 0.303 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.318, + 0.473, + 0.546 + ], + "angle": 0, + "content": "This paper proposes minimal solutions to uncalibrated two-view geometry with known epipoles. Exploiting the epipoles, we can reduce the number of point correspondences needed to find the fundamental matrix together with the intrinsic parameters: the focal length and the radial lens distortion. We define four cases by the number of available epipoles and unknown intrinsic parameters, then derive a closed-form solution for each case formulated as a higher-order polynomial in a single variable. The proposed solvers are more numerically stable and faster by orders of magnitude than the conventional 6- or 7-point algorithms. Moreover, we demonstrate by experiments on the human pose dataset that the proposed method can solve two-view geometry even with 2D human pose, of which point localization is noisier than general feature point detectors." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.574, + 0.21, + 0.59 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.599, + 0.47, + 0.75 + ], + "angle": 0, + "content": "Solving the two-view geometry of uncalibrated cameras is one of the basic tasks for many computer vision applications such as the structure-from-motion [1, 31], Visual-SLAM [6, 26], and novel view synthesis [4, 25]. The goal of this problem is to find the fundamental matrix and the intrinsic parameters of the two cameras from point correspondences. Since point correspondences are generally contaminated by outliers, many efforts have been devoted to develop efficient and numerically stable solvers that can be incorporated into RANSAC [9] to extract a set of inlier point pairs." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.75, + 0.471, + 0.902 + ], + "angle": 0, + "content": "It is known that the fundamental matrix with an unknown focal length and known principal points can be determined by six point correspondences. Stewenius et al. [34] first developed a minimal solution to this problem by manually deriving Gröbner basis. Then, other methods were proposed based on various approaches, e.g. the hidden variable technique [23], the polynomial eigenvalue problem [19], the automatic generator [21]. Following the success of the 6-point algorithms, research interests have been expanded to deal with the radial lens distortion. Jiang et al. [15] and" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.288, + 0.895, + 0.41 + ], + "angle": 0, + "content": "Kuang et al. [18] showed that the fundamental matrix with both unknown focal length and unknown radial distortion can be solved by seven point correspondences. However, with more intrinsic parameters to be estimated, new issues arise in terms of numerical stability and computational efficiency. The root cause is that those methods assume general conditions with no restrictions on the camera motion and thus cannot reduce the number of point correspondences." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.413, + 0.895, + 0.717 + ], + "angle": 0, + "content": "To address the above issue, we assume that two cameras are mutually observed, as shown in Fig. 1. This is not a rare and limited situation but occurs in real applications. For example, multiple cameras are installed to capture human behaviors from \\(360^{\\circ}\\) views in dataset creation (Figs. 2a and 2b). In dynamic scenes such as multi-agent Visual-SLAM, robots collaboratively create a single map of a wide area (Fig. 2c). Visual-SLAM can also be applied to calibrate camera networks consisting of fixed and moving cameras (Fig. 2d). In those scenarios, epipoles or 2D positions of the camera center are directly obtainable from images. Epipoles constrain a fundamental matrix to be rank-deficient, thus reducing the number of point correspondences. Nistér [27] showed a theory for finding a relative rotation of calibrated cameras with a single epipole. Ito et al. [14] utilized epipole(s) for fundamental matrix estimation, then Sato [30] generalized it to three- and four-view geometry. However, both methods are based on the DLT algorithm [11], thus not minimal solutions. They also do not address how to find the intrinsic parameters." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.896, + 0.902 + ], + "angle": 0, + "content": "In this paper, we propose minimal solutions utilizing epipole(s) to determine a fundamental matrix with unknown intrinsic camera parameters: focal length and radial lens distortion. The proposed method has four variations depending on the number of available epipoles and the number of unknown parameters to be estimated. Moreover, we introduce a simple regularization term to fix the epipoles during the non-linear optimization, which is conducted on inliers after RANSAC. Through exhaustive experiments, we show that the proposed algorithms provide more reliable estimations than the conventional methods while achieving a significant acceleration by orders of magnitude." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13361" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.098, + 0.088, + 0.45, + 0.183 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.078, + 0.189, + 0.468, + 0.216 + ], + "angle": 0, + "content": "(a) Single epipole case. The projection of the second camera is observed as \\(\\mathbf{e}\\) in the first camera." + }, + { + "type": "image", + "bbox": [ + 0.097, + 0.217, + 0.45, + 0.312 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.078, + 0.318, + 0.468, + 0.345 + ], + "angle": 0, + "content": "(b) Two epipoles case. The two cameras are mutually observed as e and \\(\\mathbf{e}^{\\prime}\\) in each image." + }, + { + "type": "image_caption", + "bbox": [ + 0.116, + 0.351, + 0.424, + 0.365 + ], + "angle": 0, + "content": "Figure 1. Two-view geometry with known epipoles." + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.377, + 0.237, + 0.47 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.1, + 0.474, + 0.216, + 0.488 + ], + "angle": 0, + "content": "(a) HumanEva [32]" + }, + { + "type": "image", + "bbox": [ + 0.25, + 0.376, + 0.458, + 0.469 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.261, + 0.474, + 0.446, + 0.488 + ], + "angle": 0, + "content": "(b) Panoptic studio dataset [16]" + }, + { + "type": "image", + "bbox": [ + 0.08, + 0.489, + 0.236, + 0.581 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.248, + 0.489, + 0.461, + 0.581 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.078, + 0.586, + 0.47, + 0.614 + ], + "angle": 0, + "content": "(c) Collaborative Visual- (d) SLAM-based calibration for surveilSLAM [28, 36] lance and moving cameras [29]" + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.618, + 0.468, + 0.646 + ], + "angle": 0, + "content": "Figure 2. Mutual camera projections in applications. (a)-(b): Human pose dataset. (c)-(d): Multi-agent Visual-SLAM." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.669, + 0.375, + 0.686 + ], + "angle": 0, + "content": "2. Uncalibrated two-view geometry" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.694, + 0.468, + 0.828 + ], + "angle": 0, + "content": "This section describes the theoretical background of two-view geometry for uncalibrated cameras. We represent 2D points as their homogeneous coordinates, i.e. \\(\\mathbf{m} = [u,v,1]^{\\mathrm{T}}\\), and assume a pinhole camera model whose intrinsic parameters are partially known: the principal point is approximated by the image center; the skewness is zero. Solving uncalibrated two-view geometry is to find the focal length \\(f\\) and the radial lens distortion \\(k\\) as well as the relative rotation \\(\\mathbb{R}\\) and translation \\(\\mathfrak{t}\\) between the two cameras." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.83, + 0.468, + 0.874 + ], + "angle": 0, + "content": "Given \\( n \\) pairs of a 2D point correspondence \\( \\{\\mathbf{m}_i \\leftrightarrow \\mathbf{m}_i'\\} \\) between the two cameras, each point pair is constrained by a \\( 3 \\times 3 \\) fundamental matrix \\( \\mathbf{F} \\):" + }, + { + "type": "equation", + "bbox": [ + 0.167, + 0.883, + 0.469, + 0.903 + ], + "angle": 0, + "content": "\\[\n\\mathbf {m} _ {i} ^ {\\prime} ^ {\\top} \\mathbf {F m} _ {i} = \\left(\\mathbf {m} _ {i} ^ {\\prime} \\otimes \\mathbf {m} _ {i}\\right) ^ {\\top} \\mathbf {f} = 0, \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.092, + 0.891, + 0.12 + ], + "angle": 0, + "content": "where \\(\\otimes\\) denotes the Kronecker product and \\(\\mathbf{f}\\) is a 9-dim vector representation of \\(\\mathbf{F}\\)." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.121, + 0.891, + 0.167 + ], + "angle": 0, + "content": "Epipoles, \\(\\mathbf{e} = [x,y,1]^{\\top}\\) and \\(\\mathbf{e}' = [x',y',1]^{\\top}\\), are the 2D projections of the image center of one camera onto the image plane of the other camera, which satisfy" + }, + { + "type": "equation", + "bbox": [ + 0.64, + 0.177, + 0.891, + 0.193 + ], + "angle": 0, + "content": "\\[\n\\mathbf {F} \\mathbf {e} = \\mathbf {F} ^ {\\top} \\mathbf {e} ^ {\\prime} = \\mathbf {0}. \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.205, + 0.89, + 0.234 + ], + "angle": 0, + "content": "Equation (2) leads to one of the constraints on \\(\\mathbf{F}\\), i.e. \\(\\operatorname*{det}(\\mathbf{F}) = 0\\). Thus, \\(\\mathbf{F}\\) is of rank two." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.235, + 0.89, + 0.265 + ], + "angle": 0, + "content": "When the two cameras can be assumed to have the same focal length \\( f \\), another constraint is given by" + }, + { + "type": "equation", + "bbox": [ + 0.588, + 0.274, + 0.891, + 0.291 + ], + "angle": 0, + "content": "\\[\n2 F Q F ^ {\\top} Q F Q - \\operatorname {t r} \\left(F Q F ^ {\\top} Q\\right) F Q = 0, \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.302, + 0.891, + 0.361 + ], + "angle": 0, + "content": "where \\(\\mathbb{Q} = \\mathrm{diag}(f^2, f^2, 1)\\). Equation (3) is the necessary and sufficient conditions to recover \\(\\mathbf{R}\\) and \\(\\mathbf{t}\\) by decomposing \\(\\mathbf{F}\\). Eliminating \\(f\\), we can rewrite Eq. (3) in a closed-form w.r.t. \\(\\mathbf{F}\\) [20] as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.521, + 0.371, + 0.891, + 0.528 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} h (\\mathbf {F}) = F _ {1 1} F _ {1 3} ^ {3} F _ {3 1} + F _ {1 3} ^ {2} F _ {2 1} F _ {2 3} F _ {3 1} + F _ {1 1} F _ {1 3} F _ {2 3} ^ {2} F _ {3 1} \\\\ + F _ {2 1} F _ {2 3} ^ {3} F _ {3 1} - F _ {1 1} F _ {1 3} F _ {3 1} ^ {3} - F _ {2 1} F _ {2 3} F _ {3 1} ^ {3} + F _ {1 2} F _ {1 3} ^ {3} F _ {3 2} \\\\ + F _ {1 3} ^ {2} F _ {2 2} F _ {2 3} F _ {3 2} + F _ {1 2} F _ {1 3} F _ {2 3} ^ {2} F _ {3 2} + F _ {2 2} F _ {2 3} ^ {3} F _ {3 2} \\\\ - F _ {1 2} F _ {1 3} F _ {3 1} ^ {2} F _ {3 2} - F _ {2 2} F _ {2 3} F _ {3 1} ^ {2} F _ {3 2} - F _ {1 1} F _ {1 3} F _ {3 1} F _ {3 2} ^ {2} \\\\ - F _ {2 1} F _ {2 3} F _ {3 1} F _ {3 2} ^ {2} - F _ {1 2} F _ {1 3} F _ {3 2} ^ {3} - F _ {2 2} F _ {2 3} F _ {3 2} ^ {3} \\tag {4} \\\\ - F _ {1 1} ^ {2} F _ {1 3} ^ {2} F _ {3 3} - F _ {1 2} ^ {2} F _ {1 3} ^ {2} F _ {3 3} - 2 F _ {1 1} F _ {1 3} F _ {2 1} F _ {2 3} F _ {3 3} \\\\ - 2 F _ {1 2} F _ {1 3} F _ {2 2} F _ {2 3} F _ {3 3} - F _ {2 1} ^ {2} F _ {2 3} ^ {2} F _ {3 3} - F _ {2 2} ^ {2} F _ {2 3} ^ {2} F _ {3 3} \\\\ + F _ {1 1} ^ {2} F _ {3 1} ^ {2} F _ {3 3} + F _ {2 1} ^ {2} F _ {3 1} ^ {2} F _ {3 3} + 2 F _ {1 1} F _ {1 2} F _ {3 1} F _ {3 2} F _ {3 3} \\\\ + 2 F _ {2 1} F _ {2 2} F _ {3 1} F _ {3 2} F _ {3 3} + F _ {1 2} ^ {2} F _ {3 2} ^ {2} F _ {3 3} + F _ {2 2} ^ {2} F _ {3 2} ^ {2} F _ {3 3} = 0, \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.538, + 0.776, + 0.553 + ], + "angle": 0, + "content": "where \\(F_{ij}\\) denotes the \\((i,j)\\) element of \\(\\mathbf{F}\\)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.553, + 0.891, + 0.597 + ], + "angle": 0, + "content": "Once we obtain an \\( \\mathbf{F} \\) such that \\( \\operatorname*{det}(\\mathbb{F}) = 0 \\) and Eq. (3) (or Eq. (4)), the focal length \\( f \\) can be computed in a closed-form [20]:" + }, + { + "type": "equation", + "bbox": [ + 0.525, + 0.606, + 0.891, + 0.689 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} F _ {1 2} F _ {1 3} F _ {3 3} ^ {2} + F _ {2 2} F _ {2 3} F _ {3 3} ^ {2} \\\\ f ^ {2} = \\frac {- F _ {1 3} ^ {2} F _ {3 2} F _ {3 3} - F _ {2 3} ^ {2} F _ {3 2} F _ {3 3}}{F _ {1 1} F _ {1 3} F _ {3 1} F _ {3 2} + F _ {2 1} F _ {2 3} F _ {3 1} F _ {3 2} + F _ {1 2} F _ {1 3} F _ {3 2} ^ {2}}. \\tag {5} \\\\ + F _ {2 2} F _ {2 3} F _ {3 2} ^ {2} - F _ {1 2} ^ {2} F _ {3 2} F _ {3 3} - F _ {2 2} ^ {2} F _ {3 2} F _ {3 3} \\\\ - F _ {1 1} F _ {1 2} F _ {3 1} F _ {3 3} - F _ {2 1} F _ {2 2} F _ {3 1} F _ {3 3} \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.698, + 0.891, + 0.743 + ], + "angle": 0, + "content": "It is well known that the relative motion, \\( \\mathbf{R} \\) and \\( \\mathbf{t} \\), can be obtained by using a singular value decomposition [11] or a closed-form method [13]." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.744, + 0.891, + 0.804 + ], + "angle": 0, + "content": "If the cameras have a wide angle lens with a radial distortion parameter \\( k \\), a 2D point \\( \\mathbf{m} \\) is observed as a radially distorted point \\( \\hat{\\mathbf{m}} \\). The relation can be written by using the division model [10]:" + }, + { + "type": "equation", + "bbox": [ + 0.594, + 0.812, + 0.891, + 0.861 + ], + "angle": 0, + "content": "\\[\n\\mathbf {m} = \\frac {1}{1 + k r} \\hat {\\mathbf {m}} \\propto \\left[ \\begin{array}{c} \\hat {u} \\\\ \\hat {v} \\\\ 1 + k r \\end{array} \\right], \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.87, + 0.891, + 0.901 + ], + "angle": 0, + "content": "where \\(r = \\hat{u}^2 +\\hat{v}^2\\) . Hereafter, we use the hat symbol \\(\\hat{\\cdot}\\) to express radially distorted values." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13362" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.078, + 0.09, + 0.423, + 0.108 + ], + "angle": 0, + "content": "3. Finding F-matrix with known epipoles" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.115, + 0.473, + 0.328 + ], + "angle": 0, + "content": "In this section, we propose four different algorithms depending on the number of unknown intrinsic parameters and the number of known epipoles. The basic strategy commonly used in all methods is to parameterize a fundamental matrix \\( \\mathbf{F} \\) as a linear combination of the null space of a coefficient matrix computed from epipoles and point correspondences. We reduce the number of unknown variables to one and employ Eq. (4) to lead to a higher-order polynomial equation of the single variable. The fundamental matrix \\( \\mathbf{F} \\) is obtained by substituting the real roots of the polynomial equation into the linear combination of the null space. The null space is derived from the epipoles, and Eq. (4) is used for the root finding, therefore, both the intrinsic and extrinsic parameters can be recovered from the computed \\( \\mathbf{F} \\)." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.337, + 0.421, + 0.354 + ], + "angle": 0, + "content": "3.1. 2-pt algorithm for \\(\\mathbf{F} + \\mathbf{f}\\) with two epipoles" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.36, + 0.47, + 0.422 + ], + "angle": 0, + "content": "We start with the simplest case where two epipoles \\(\\mathbf{e}\\) and \\(\\mathbf{e}'\\) are observed by each camera with an unknown focal length \\(f\\) but no lens distortion. If we define the \\(3 \\times 3\\) identity matrix by \\(\\mathbf{I}\\) and a \\(6 \\times 9\\) matrix \\(\\mathbb{N}_1\\) by" + }, + { + "type": "equation", + "bbox": [ + 0.188, + 0.43, + 0.47, + 0.496 + ], + "angle": 0, + "content": "\\[\n\\mathrm {N} _ {1} = \\left[ \\begin{array}{c c c} \\mathbf {e} ^ {\\mathrm {T}} & & \\\\ & \\mathbf {e} ^ {\\mathrm {T}} & \\\\ & & \\mathbf {e} ^ {\\mathrm {T}} \\\\ x ^ {\\prime} \\mathrm {I} & y ^ {\\prime} \\mathrm {I} & \\mathrm {I} \\end{array} \\right], \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.506, + 0.303, + 0.521 + ], + "angle": 0, + "content": "Eq. (2) can be written in the form" + }, + { + "type": "equation", + "bbox": [ + 0.24, + 0.534, + 0.47, + 0.549 + ], + "angle": 0, + "content": "\\[\n\\mathrm {N} _ {1} \\mathbf {f} = \\mathbf {0}. \\tag {8}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.561, + 0.427, + 0.576 + ], + "angle": 0, + "content": "Here, \\(\\mathbb{N}_1\\) is of size \\(6\\times 9\\) but its row rank is only five." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.577, + 0.469, + 0.607 + ], + "angle": 0, + "content": "Utilizing two point correspondences, a \\(8 \\times 9\\) coefficient matrix \\(\\mathbb{M}_1\\) is given by" + }, + { + "type": "equation", + "bbox": [ + 0.192, + 0.617, + 0.47, + 0.667 + ], + "angle": 0, + "content": "\\[\n\\mathrm {M} _ {1} = \\left[ \\begin{array}{c} \\mathrm {N} _ {1} \\\\ \\left(\\mathbf {m} _ {1} ^ {\\prime} \\otimes \\mathbf {m} _ {1}\\right) ^ {\\mathsf {T}} \\\\ \\left(\\mathbf {m} _ {2} ^ {\\prime} \\otimes \\mathbf {m} _ {2}\\right) ^ {\\mathsf {T}} \\end{array} \\right]. \\tag {9}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.677, + 0.179, + 0.69 + ], + "angle": 0, + "content": "Then, we have" + }, + { + "type": "equation", + "bbox": [ + 0.241, + 0.692, + 0.469, + 0.707 + ], + "angle": 0, + "content": "\\[\n\\mathrm {M} _ {1} \\mathbf {f} = \\mathbf {0}. \\tag {10}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.714, + 0.47, + 0.746 + ], + "angle": 0, + "content": "Since the row rank of \\(\\mathsf{M}_1\\) is seven, \\(\\mathbf{f}\\) can be parameterized by a linear combination of two null vectors \\(\\mathbf{v}_1\\), \\(\\mathbf{v}_2\\) of \\(\\mathsf{M}_1\\):" + }, + { + "type": "equation", + "bbox": [ + 0.221, + 0.758, + 0.469, + 0.773 + ], + "angle": 0, + "content": "\\[\n\\mathbf {f} = \\alpha \\mathbf {v} _ {2} + \\mathbf {v} _ {1}. \\tag {11}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.785, + 0.47, + 0.816 + ], + "angle": 0, + "content": "Substituting Eq. (11) into Eq. (4), we obtain a fifth-order equation for the single variable \\(\\alpha\\), which is represented by" + }, + { + "type": "equation", + "bbox": [ + 0.085, + 0.826, + 0.469, + 0.844 + ], + "angle": 0, + "content": "\\[\nh (\\mathbb {F} (\\alpha)) = c _ {5} \\alpha^ {5} + c _ {4} \\alpha^ {4} + c _ {3} \\alpha^ {3} + c _ {2} \\alpha^ {2} + c _ {1} \\alpha + c _ {0} = 0. \\tag {12}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.856, + 0.47, + 0.9 + ], + "angle": 0, + "content": "Once we found the roots of Eq. (12), the fundamental matrix \\( \\mathbf{F} \\) is then obtained from Eq. (11). This algorithm gives at most five solutions." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.091, + 0.854, + 0.108 + ], + "angle": 0, + "content": "3.2. 4-pt algorithm for \\(\\mathbf{F} + \\mathbf{f}\\) with single epipole" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.116, + 0.892, + 0.193 + ], + "angle": 0, + "content": "When one of the two epipoles is only available, we can solve the \\( \\mathbf{F} + f \\) problem by adding more two point correspondences. Using four point correspondences together with the single epipole \\( \\mathbf{e} \\), we can construct a \\( 7 \\times 9 \\) coefficient matrix \\( \\mathbb{M}_2 \\) by" + }, + { + "type": "equation", + "bbox": [ + 0.615, + 0.206, + 0.892, + 0.311 + ], + "angle": 0, + "content": "\\[\n\\mathrm {M} _ {2} = \\left[ \\begin{array}{c c c} \\mathbf {e} ^ {\\top} & & \\\\ & \\mathbf {e} ^ {\\top} & \\\\ & & \\mathbf {e} ^ {\\top} \\\\ \\left(\\mathbf {m} _ {1} ^ {\\prime} \\otimes \\mathbf {m} _ {1}\\right) ^ {\\top} & & \\\\ & \\vdots & \\\\ \\left(\\mathbf {m} _ {4} ^ {\\prime} \\otimes \\mathbf {m} _ {4}\\right) ^ {\\top} & & \\end{array} \\right], \\tag {13}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.324, + 0.602, + 0.337 + ], + "angle": 0, + "content": "which satisfies" + }, + { + "type": "equation", + "bbox": [ + 0.663, + 0.345, + 0.892, + 0.36 + ], + "angle": 0, + "content": "\\[\n\\mathrm {M} _ {2} \\mathbf {f} = \\mathbf {0}. \\tag {14}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.375, + 0.892, + 0.435 + ], + "angle": 0, + "content": "The row rank of \\(\\mathbb{M}_2\\) is seven, which is identical to \\(\\mathbb{M}_1\\). Consequently, we can find \\(\\mathbb{F}\\) using exactly the same approach as in Eqs. (11) and (12). The number of the real solutions of this algorithm is at most five." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.451, + 0.864, + 0.468 + ], + "angle": 0, + "content": "3.3. 3-pt algorithm for \\(\\mathbf{F} + \\mathbf{f} + \\mathbf{k}\\) with two epipoles" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.476, + 0.892, + 0.537 + ], + "angle": 0, + "content": "We address a more complicated problem where a radial distortion parameter \\( k \\) is additionally unknown. Since we have two epipoles in this case, this problem can be solved using three point correspondences." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.539, + 0.892, + 0.6 + ], + "angle": 0, + "content": "In this problem, the epipoles, \\(\\hat{\\mathbf{e}}\\) and \\(\\hat{\\mathbf{e}}^{\\prime}\\), are observed in the distorted image coordinates, as with the point correspondences \\(\\hat{\\mathbf{m}}\\). Using Eq. (6), we can represent the undistorted epipoles, \\(\\mathbf{e}\\) and \\(\\mathbf{e}^{\\prime}\\), as" + }, + { + "type": "equation", + "bbox": [ + 0.597, + 0.614, + 0.892, + 0.67 + ], + "angle": 0, + "content": "\\[\n\\mathbf {e} = \\frac {1}{1 + k z} \\hat {\\mathbf {e}} \\propto \\left[ \\begin{array}{c} \\hat {x} \\\\ \\hat {y} \\\\ 1 + k z \\end{array} \\right], \\tag {15}\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.596, + 0.666, + 0.797, + 0.713 + ], + "angle": 0, + "content": "\\[\n\\mathbf {e} ^ {\\prime} = \\frac {1}{1 + k z ^ {\\prime}} \\hat {\\mathbf {e}} ^ {\\prime} \\propto \\left[ \\begin{array}{c} \\hat {x} ^ {\\prime} \\\\ \\hat {y} ^ {\\prime} \\\\ 1 + k z ^ {\\prime} \\end{array} \\right],\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.727, + 0.892, + 0.759 + ], + "angle": 0, + "content": "where \\(z = \\hat{x}^2 +\\hat{y}^2\\) and \\(z^{\\prime} = \\hat{x}^{\\prime 2} + \\hat{y}^{\\prime 2}\\) . Note that the radial distortion \\(k\\) is an unknown parameter." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.761, + 0.871, + 0.776 + ], + "angle": 0, + "content": "Similar to Eqs. (7) and (8), we can rewrite Eq. (2) by" + }, + { + "type": "equation", + "bbox": [ + 0.663, + 0.793, + 0.892, + 0.808 + ], + "angle": 0, + "content": "\\[\n\\mathrm {N} _ {2} \\mathbf {f} = \\mathbf {0}, \\tag {16}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.501, + 0.825, + 0.547, + 0.838 + ], + "angle": 0, + "content": "where" + }, + { + "type": "equation", + "bbox": [ + 0.585, + 0.84, + 0.892, + 0.906 + ], + "angle": 0, + "content": "\\[\n\\mathrm {N} _ {2} = \\left[ \\begin{array}{c c c} \\mathbf {e} ^ {\\top} & & \\\\ & \\mathbf {e} ^ {\\top} & \\\\ & & \\mathbf {e} ^ {\\top} \\\\ \\hat {x} ^ {\\prime} \\mathrm {I} & \\hat {y} ^ {\\prime} \\mathrm {I} & (1 + k z ^ {\\prime}) \\mathrm {I} \\end{array} \\right]. \\tag {17}\n\\]" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13363" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.078, + 0.092, + 0.411, + 0.108 + ], + "angle": 0, + "content": "The null space of \\(\\mathbb{N}_2\\) can be symbolically given by" + }, + { + "type": "equation", + "bbox": [ + 0.078, + 0.12, + 0.117, + 0.134 + ], + "angle": 0, + "content": "\\[\n\\mathsf {V} _ {1} =\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.082, + 0.137, + 0.477, + 0.287 + ], + "angle": 0, + "content": "\\[\n\\left[ \\begin{array}{c c c c} \\hat {y} \\hat {y} ^ {\\prime} & \\hat {y} ^ {\\prime} (1 + k z) & \\hat {y} (1 + k z ^ {\\prime}) & (1 + k z) (1 + k z ^ {\\prime}) \\\\ - \\hat {x} \\hat {y} ^ {\\prime} & 0 & - \\hat {x} (1 + k z ^ {\\prime}) & 0 \\\\ 0 & - \\hat {x} \\hat {y} ^ {\\prime} & 0 & - \\hat {x} (1 + k z ^ {\\prime}) \\\\ - \\hat {x} ^ {\\prime} \\hat {y} & - \\hat {x} ^ {\\prime} (1 + k z) & 0 & 0 \\\\ \\hat {x} \\hat {x} ^ {\\prime} & 0 & 0 & 0 \\\\ 0 & \\hat {x} \\hat {x} ^ {\\prime} & 0 & 0 \\\\ 0 & 0 & - \\hat {x} ^ {\\prime} \\hat {y} & - \\hat {x} ^ {\\prime} (1 + k z) \\\\ 0 & 0 & \\hat {x} \\hat {x} ^ {\\prime} & 0 \\\\ 0 & 0 & 0 & \\hat {x} \\hat {x} ^ {\\prime} \\end{array} \\right] \\tag {18}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.29, + 0.47, + 0.319 + ], + "angle": 0, + "content": "Thus, the fundamental matrix can be represented as a linear combination of the column vectors of \\( \\mathrm{V}_1 \\), i.e." + }, + { + "type": "equation", + "bbox": [ + 0.235, + 0.332, + 0.47, + 0.348 + ], + "angle": 0, + "content": "\\[\n\\mathbf {f} = \\mathrm {V} _ {1} \\boldsymbol {\\alpha} _ {1}, \\tag {19}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.36, + 0.264, + 0.374 + ], + "angle": 0, + "content": "where \\(\\alpha_{1}\\) is a 4-dim vector." + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.375, + 0.469, + 0.406 + ], + "angle": 0, + "content": "We now have three point correspondences, which satisfy \\((\\mathbf{m}_i' \\otimes \\mathbf{m}_i)^\\top \\mathbf{f} = 0\\). If we define a \\(3 \\times 4\\) matrix \\(\\mathsf{G}_1\\) by" + }, + { + "type": "equation", + "bbox": [ + 0.185, + 0.416, + 0.469, + 0.465 + ], + "angle": 0, + "content": "\\[\n\\mathbf {G} _ {1} = \\left[ \\begin{array}{l} \\left(\\mathbf {m} _ {1} ^ {\\prime} \\otimes \\mathbf {m} _ {1}\\right) ^ {\\mathrm {T}} \\\\ \\left(\\mathbf {m} _ {2} ^ {\\prime} \\otimes \\mathbf {m} _ {2}\\right) ^ {\\mathrm {T}} \\\\ \\left(\\mathbf {m} _ {3} ^ {\\prime} \\otimes \\mathbf {m} _ {3}\\right) ^ {\\mathrm {T}} \\end{array} \\right] \\mathrm {V} _ {1}, \\tag {20}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.476, + 0.148, + 0.489 + ], + "angle": 0, + "content": "we obtain" + }, + { + "type": "equation", + "bbox": [ + 0.168, + 0.497, + 0.469, + 0.547 + ], + "angle": 0, + "content": "\\[\n\\left[ \\begin{array}{l} \\left(\\mathbf {m} _ {1} ^ {\\prime} \\otimes \\mathbf {m} _ {1}\\right) ^ {\\mathsf {T}} \\\\ \\left(\\mathbf {m} _ {2} ^ {\\prime} \\otimes \\mathbf {m} _ {2}\\right) ^ {\\mathsf {T}} \\\\ \\left(\\mathbf {m} _ {3} ^ {\\prime} \\otimes \\mathbf {m} _ {3}\\right) ^ {\\mathsf {T}} \\end{array} \\right] \\mathbf {f} = \\mathbb {G} _ {1} \\boldsymbol {\\alpha} _ {1} = \\mathbf {0}. \\tag {21}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.557, + 0.47, + 0.603 + ], + "angle": 0, + "content": "The unknown vector \\(\\alpha_{1}\\) can be determined as the kernel of \\(\\mathsf{G}_1\\) up to scale. Since \\(\\mathsf{G}_1\\) is of size \\(3\\times 4\\), the kernel can be symbolically computed as a 4-dim vector:" + }, + { + "type": "equation", + "bbox": [ + 0.192, + 0.615, + 0.469, + 0.631 + ], + "angle": 0, + "content": "\\[\n\\boldsymbol {\\alpha} _ {1} \\propto \\operatorname {K e r} \\left(\\mathrm {G} _ {1}\\right) = \\mathrm {Q} _ {1} \\boldsymbol {\\beta} _ {1}, \\tag {22}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.642, + 0.47, + 0.673 + ], + "angle": 0, + "content": "where \\(\\mathbb{Q}_1\\) is a \\(4\\times 5\\) matrix and \\(\\beta_{1} = [k^{4},k^{3},k^{2},k,1]^{\\top}\\). We can replace \\(\\alpha_{1}\\) with \\(\\mathbb{Q}_1\\beta_1\\), then Eq. (19) can be rewritten as" + }, + { + "type": "equation", + "bbox": [ + 0.199, + 0.686, + 0.469, + 0.701 + ], + "angle": 0, + "content": "\\[\n\\mathbf {f} = \\mathrm {V} _ {1} \\boldsymbol {\\alpha} _ {1} = \\mathrm {V} _ {1} \\mathrm {Q} _ {1} \\boldsymbol {\\beta} _ {1}. \\tag {23}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.713, + 0.469, + 0.744 + ], + "angle": 0, + "content": "Plugging Eq. (23) into Eq. (4), we finally obtain a 16th-degree polynomial equation in \\( k \\):" + }, + { + "type": "equation", + "bbox": [ + 0.136, + 0.754, + 0.469, + 0.772 + ], + "angle": 0, + "content": "\\[\nh (\\mathbb {F} (k)) = c _ {1 6} k ^ {1 6} + \\dots + c _ {1} k + c _ {0} = 0. \\tag {24}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.783, + 0.469, + 0.827 + ], + "angle": 0, + "content": "We can recover \\( \\mathbf{f} \\) by substituting the real roots of Eq. (24) into Eq. (23). This algorithm provides at most 16 real solutions." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.091, + 0.874, + 0.108 + ], + "angle": 0, + "content": "3.4. 5-pt algorithm for \\(\\mathbf{F} + \\mathbf{f} + \\mathbf{k}\\) with single epipole" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.114, + 0.892, + 0.187 + ], + "angle": 0, + "content": "Given only a single epipole \\(\\mathbf{e}\\), we need two additional point pairs to solve the \\(F + f + k\\) problem. We omit the details of the derivation and describe the differences only because the procedure of this algorithm is basically similar to Sec. 3.3." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.186, + 0.892, + 0.247 + ], + "angle": 0, + "content": "The null space of \\(\\left[ \\begin{array}{ccc}\\mathbf{e}^{\\mathsf{T}} & & \\\\ & \\mathbf{e}^{\\mathsf{T}} & \\\\ & & \\mathbf{e}^{\\mathsf{T}} \\end{array} \\right]\\) can be symbolically given by" + }, + { + "type": "equation", + "bbox": [ + 0.523, + 0.259, + 0.562, + 0.273 + ], + "angle": 0, + "content": "\\[\nV _ {2} =\n\\]" + }, + { + "type": "equation", + "bbox": [ + 0.529, + 0.276, + 0.892, + 0.416 + ], + "angle": 0, + "content": "\\[\n\\left[ \\begin{array}{c c c c c c} - \\hat {y} & 1 + k z & 0 & 0 & 0 & 0 \\\\ \\hat {x} & 0 & 0 & 0 & 0 & 0 \\\\ 0 & - \\hat {x} & 0 & 0 & 0 & 0 \\\\ 0 & 0 & - \\hat {y} & 1 + k z & 0 & 0 \\\\ 0 & 0 & \\hat {x} & 0 & 0 & 0 \\\\ 0 & 0 & 0 & - \\hat {x} & 0 & 0 \\\\ 0 & 0 & 0 & 0 & - \\hat {y} & 1 + k z \\\\ 0 & 0 & 0 & 0 & \\hat {x} & 0 \\\\ 0 & 0 & 0 & 0 & 0 & - \\hat {x} \\end{array} \\right]. \\tag {25}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.425, + 0.892, + 0.532 + ], + "angle": 0, + "content": "Since \\(\\mathbf{V}_2\\) is of size \\(9 \\times 6\\), the unknown vector \\(\\alpha_2\\) for this problem becomes a 6-dim vector. Using the five point correspondences, \\(\\mathsf{G}_2\\) is represented as a \\(5 \\times 6\\) matrix, as shown in Eq. (20). Then, we can symbolically obtain the kernel of \\(\\mathsf{G}_2\\), which is given as the matrix-vector product of a \\(6 \\times 6\\) matrix \\(\\mathbb{Q}_2\\) and \\(\\beta_2 = [k^5, k^4, k^3, k^2, k, 1]^{\\mathrm{T}}\\). Now we can express the fundamental matrix by" + }, + { + "type": "equation", + "bbox": [ + 0.651, + 0.544, + 0.891, + 0.56 + ], + "angle": 0, + "content": "\\[\n\\mathbf {f} = \\mathrm {V} _ {2} \\mathrm {Q} _ {2} \\beta_ {2}. \\tag {26}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.571, + 0.891, + 0.601 + ], + "angle": 0, + "content": "Substituting Eq. (26) into Eq. (4), we finally obtain a 21st-order polynomial equation in \\(k\\), i.e." + }, + { + "type": "equation", + "bbox": [ + 0.558, + 0.612, + 0.891, + 0.63 + ], + "angle": 0, + "content": "\\[\nh (\\mathbb {F} (k)) = c _ {2 1} k ^ {2 1} + \\dots + c _ {1} k + c _ {0} = 0. \\tag {27}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.64, + 0.804, + 0.654 + ], + "angle": 0, + "content": "Thus, we can obtain at most 21 real solutions." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.665, + 0.707, + 0.679 + ], + "angle": 0, + "content": "3.5. Non-linear refinement" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.688, + 0.892, + 0.764 + ], + "angle": 0, + "content": "After running a RANSAC scheme, we generally obtain many inlier points and perform a non-linear refinement to polish the accuracy of the parameters. For example, minimizing the symmetric epipolar distance is one of the major cost functions in the literature [11], i.e." + }, + { + "type": "equation", + "bbox": [ + 0.515, + 0.772, + 0.891, + 0.825 + ], + "angle": 0, + "content": "\\[\nL _ {\\text {s y m}} = \\sum_ {i = 1} ^ {n} \\frac {\\left(\\mathbf {m} _ {i} ^ {\\prime} {} ^ {\\top} \\mathbf {F} \\mathbf {m} _ {i}\\right) ^ {2}}{\\left[ \\mathbf {F} \\mathbf {m} _ {i} \\right] _ {1} ^ {2} + \\left[ \\mathbf {F} \\mathbf {m} _ {i} \\right] _ {2} ^ {2}} + \\frac {\\left(\\mathbf {m} _ {i} ^ {\\prime} {} ^ {\\top} \\mathbf {F} \\mathbf {m} _ {i}\\right) ^ {2}}{\\left[ \\mathbf {F} ^ {\\top} \\mathbf {m} _ {i} ^ {\\prime} \\right] _ {1} ^ {2} + \\left[ \\mathbf {F} ^ {\\top} \\mathbf {m} _ {i} ^ {\\prime} \\right] _ {2} ^ {2}}, \\tag {28}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.891, + 0.855 + ], + "angle": 0, + "content": "where \\([\\mathbf{F}\\mathbf{m}_i]_j^2\\) denotes the square of the j-th element of the vector \\(\\mathbf{F}\\mathbf{m}_i\\)." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.856, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Since we have an initial guess of the focal length of the two images as \\( f_{1} = f_{2} = f \\), we can parameterize the fundamental matrix by \\( \\mathbf{F} = \\mathrm{diag}(1,1,f_2)\\mathbf{E}\\mathrm{diag}(1,1,f_1) \\)" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13364" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.077, + 0.092, + 0.468, + 0.152 + ], + "angle": 0, + "content": "where \\(\\mathbf{E}\\) represents an essential matrix. Thus, we can use the Helmke's method [12] to update \\(\\mathbf{E}\\) with preserving 5 DoFs. Also, we initialize the lens distortion of the two images by \\(k_{1} = k_{2} = k\\)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.155, + 0.468, + 0.232 + ], + "angle": 0, + "content": "However, those typical approaches of the non-linear refinement do not assume that epipoles are known, which in turn may degrade the fundamental matrix obtained by the proposed method. To avoid this issue, we introduce a regularization term of Eq. (2) as follows:" + }, + { + "type": "equation", + "bbox": [ + 0.183, + 0.246, + 0.468, + 0.268 + ], + "angle": 0, + "content": "\\[\nL _ {\\mathrm {e p i}} = \\left\\| \\mathbf {F} \\mathbf {e} \\right\\| ^ {2} + \\left\\| \\mathbf {F} ^ {\\mathsf {T}} \\mathbf {e} ^ {\\prime} \\right\\| ^ {2}. \\tag {29}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.282, + 0.468, + 0.331 + ], + "angle": 0, + "content": "Note that the epipoles, \\(\\mathbf{e}\\) and \\(\\mathbf{e}^{\\prime}\\), are undistorted using Eq. (15) with \\(k_{1}\\) and \\(k_{2}\\). In the case of the single epipole, the second term \\(\\left\\| \\mathbf{F}^{\\mathsf{T}}\\mathbf{e}^{\\prime}\\right\\|^{2}\\) is simply dropped." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.332, + 0.468, + 0.364 + ], + "angle": 0, + "content": "The total cost function of the proposed scheme is given by jointly optimizing \\( L_{\\mathrm{sym}} \\) and \\( L_{\\mathrm{epi}} \\) with a weight \\( w \\):" + }, + { + "type": "equation", + "bbox": [ + 0.204, + 0.38, + 0.468, + 0.397 + ], + "angle": 0, + "content": "\\[\nL = L _ {\\text {s y m}} + w L _ {\\text {e p i}}. \\tag {30}\n\\]" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.416, + 0.321, + 0.433 + ], + "angle": 0, + "content": "4. Degenerate configurations" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.443, + 0.468, + 0.519 + ], + "angle": 0, + "content": "Analysis of the degenerate configurations is important to avoid ambiguous 3D shape reconstructions and use the proposed method in real applications. Due to limitations of space, we give several simple examples for \\( \\mathbf{F} + f \\) problem with two known epipoles in this section." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.522, + 0.468, + 0.779 + ], + "angle": 0, + "content": "Degenerate configurations of two-view geometry in general cases have been extensively studied for the past decades [5, 17, 33, 35]. One typical situation that could often occur in practice is forward motion, where both focal length and radial distortion cannot be uniquely determined regardless of the point distributions. Forward motion alone is not the case for the proposed solvers, but forward motion with special point distributions is. One configuration where the proposed 2-point solver for \\( \\mathbf{F} + f \\) problem cannot be solved is that two epipoles and two point correspondences are collinear under forward motion. For example, the row rank of \\( \\mathbb{M}_1 \\) is less than seven in Eq. (9) when \\( \\mathbf{e} = \\mathbf{e}' = [0,0,1]^{\\mathrm{T}} \\), \\( \\mathbf{m}_i = [u_i,0,1]^{\\mathrm{T}} \\), \\( \\mathbf{m}_i' = [-u_i,0,1]^{\\mathrm{T}} \\), \\( i \\in \\{1,2\\} \\). Another well-known degenerate configuration for the general solvers is that all 3D points are on a plane. However, in our case, unique solutions can be obtained in planar scenes when two epipoles are known [30]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.781, + 0.468, + 0.9 + ], + "angle": 0, + "content": "The rigorous conditions can be given by analyzing the rank of submatrices of \\(\\mathbb{N}_1\\) and \\(\\mathbb{M}_1\\) (\\(\\mathbb{N}_2\\) and \\(\\mathbb{M}_2\\) for the other problems as well). In other words, we first find epipoles and image points that cause rank deficiency, then link them to actual camera motions and 3D point distributions. However, as reported in the previous studies, it is not easy to reveal all possible ambiguities. We would leave the in-depth discussion to future research." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.091, + 0.633, + 0.108 + ], + "angle": 0, + "content": "5. Experiments" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.115, + 0.892, + 0.16 + ], + "angle": 0, + "content": "This section reports experimental results on synthetic and real data. We conducted all experiments on a PC with Core i7-13700k." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.169, + 0.66, + 0.186 + ], + "angle": 0, + "content": "5.1. Implementation" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.192, + 0.892, + 0.435 + ], + "angle": 0, + "content": "We have implemented five conventional methods and the four proposed methods in MATLAB, as shown in Tab. 1. We chose three Gröbner basis solvers that are the state-of-the-art based on the efficient parameterization (Eq. (4)): Larsson's 6-point solver for \\( \\mathrm{F} + f \\) problem (L6f) [21], Larsson's 7-point solver for \\( \\mathrm{F} + f + k \\) problem (L7fk) [21], and Martyushev's 7-point solver for \\( \\mathrm{F} + f + k \\) problem (M7fk) [24]. Those are designed for general scenes, therefore, epipoles are not assumed to be available. Moreover, we used two DLT-based approaches by Ito et al. [14]: the 3-point solver with two epipoles (I3), and the 5-point solver with a single epipole (I5). Although I3 and I5 do not guarantee to satisfy Eq. (3) or Eq. (4), we calculated focal length by simply applying Eq. (5) to a fundamental matrix given by I3 or I5. We used the root function for solving the polynomials of the proposed solvers, i.e. Eqs. (12), (24) and (27)." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.443, + 0.682, + 0.457 + ], + "angle": 0, + "content": "5.2. Evaluation metrics" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.466, + 0.891, + 0.497 + ], + "angle": 0, + "content": "We measured the following metrics to quantitatively evaluate the estimation accuracy:" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.505, + 0.89, + 0.535 + ], + "angle": 0, + "content": "\\(\\epsilon_{\\mathrm{F}}\\) Symmetric epipolar distance in pixels by applying \\(\\mathbf{F}_{\\mathrm{est}}\\) onto the ground-truth 2D points." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.543, + 0.821, + 0.561 + ], + "angle": 0, + "content": "\\(\\epsilon_{f}\\) Relative error by \\(|f_{\\mathrm{est}} - f_{\\mathrm{gt}}| / f_{\\mathrm{gt}} \\times 100[\\%]\\)." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.568, + 0.891, + 0.629 + ], + "angle": 0, + "content": "\\(\\epsilon_{k}\\) Normalized pixel distance \\([\\%]\\) between undistorted coordinates using \\(k_{\\mathrm{est}}\\) and \\(k_{\\mathrm{gt}}\\). 100 points were uniformly sampled, and the mean distance is normalized by the diagonal length of the image." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.636, + 0.871, + 0.669 + ], + "angle": 0, + "content": "\\(\\epsilon_{\\mathrm{R}}\\) Angle-axis error by \\(\\cos^{-1}\\left(\\frac{\\operatorname{tr}(\\mathbb{R}_{\\mathrm{gt}}^{\\mathrm{T}}\\mathbb{R}_{\\mathrm{est}}) - 1}{2}\\right)\\) [degrees]." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.677, + 0.864, + 0.71 + ], + "angle": 0, + "content": "\\(\\epsilon_{t}\\) Cosine similarity by \\(\\cos^{-1}\\left(\\frac{\\mathbf{t}_{\\mathrm{gt}}^{\\mathrm{T}}\\mathbf{t}_{\\mathrm{est}}}{\\|\\mathbf{t}_{\\mathrm{gt}}\\| \\|\\mathbf{t}_{\\mathrm{est}}\\|}\\right)\\) [degrees]." + }, + { + "type": "list", + "bbox": [ + 0.5, + 0.505, + 0.891, + 0.71 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.715, + 0.647, + 0.731 + ], + "angle": 0, + "content": "5.3. Synthetic data" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.739, + 0.89, + 0.769 + ], + "angle": 0, + "content": "We investigate the performance of the minimal solvers using synthetic data in this section." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.787, + 0.692, + 0.802 + ], + "angle": 0, + "content": "5.3.1 Scene configuration" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.811, + 0.892, + 0.901 + ], + "angle": 0, + "content": "We created synthetic scenes as follows. Two cameras were randomly located in the area of \\(5.0\\mathrm{m}\\times 5.0\\mathrm{m}\\) and \\(2.0\\mathrm{m}\\) high to project each other, as shown in Fig. 1b. Small perturbations within 5 degrees and \\(\\pm 0.2\\mathrm{m}\\) were added to the rotation and position of the cameras, respectively. The image resolution was \\(640\\times 480\\), the focal length was set to" + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13365" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.097, + 0.089, + 0.875, + 0.284 + ], + "angle": 0, + "content": "
MethodReferenceProblemDecomposability Eqs. (3) and (4)# of points# of epipoles# of solutionsApproach
L6f[21]F+f✓6015
L7fk[21]F+f+k✓7068Gröbner basis
M7fk[24]F+f+k✓7068
I5[14]F511DLT
I3[14]F321
P4fF+f✓415
P2fF+f✓225Closed-form
P5fkF+f+k✓5116
P3fkF+f+k✓3221
" + }, + { + "type": "table_caption", + "bbox": [ + 0.343, + 0.282, + 0.625, + 0.296 + ], + "angle": 0, + "content": "Table 1. Methods compared in the experiments." + }, + { + "type": "image", + "bbox": [ + 0.081, + 0.309, + 0.311, + 0.45 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.329, + 0.309, + 0.557, + 0.45 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.575, + 0.31, + 0.889, + 0.451 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.144, + 0.455, + 0.825, + 0.47 + ], + "angle": 0, + "content": "Figure 3. The cumulative histogram of numerical accuracy for \\(10^{6}\\) trials of randomly generated data without noise." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.494, + 0.47, + 0.601 + ], + "angle": 0, + "content": "\\(f = 381.3\\), which is approximately \\(80^{\\circ}\\) HFOV. The radial lens distortion was set to \\(k = -0.2 / f^{2}\\) for the \\(\\mathsf{F} + f + k\\) problem. We uniformly generated 100 3D points in the common viewing frustum of the two cameras and projected the 3D points onto the image plane. Then, we randomly picked the minimal number of the points needed for each method." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.62, + 0.266, + 0.636 + ], + "angle": 0, + "content": "5.3.2 Numerical stability" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.645, + 0.471, + 0.797 + ], + "angle": 0, + "content": "In the first test, we investigated the numerical stability of the methods in noise free data. Figure 3 summarizes a cumulative histogram of \\(\\epsilon_{\\mathrm{F}}, \\epsilon_{f}\\), and \\(\\epsilon_{k}\\) over \\(10^{6}\\) independent trials. The figure indicates that the proposed methods are numerically stable. Comparing the methods in each categories, we see that P2f and P4f are better than I3, I5, and L6f in the \\(\\mathbf{F} + f\\) problem, and P5fk and P3fk are better than L7fk and M7fk in the \\(\\mathbf{F} + f + k\\) problem. Here, it should be noted that L7fk is so unstable as to be impractical. We further investigate this issue in the following experiments." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.817, + 0.356, + 0.832 + ], + "angle": 0, + "content": "5.3.3 Robustness w.r.t. noise on points" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.84, + 0.471, + 0.903 + ], + "angle": 0, + "content": "To evaluate the robustness against the image noise, we measured the estimation errors by adding the zero-mean Gaussian noise onto point correspondences with the standard deviation \\(0 \\leq \\sigma \\leq 2\\) pixels. In this experiment, the image" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.494, + 0.892, + 0.678 + ], + "angle": 0, + "content": "noise was not added to the epipoles, that is, the ground-truth values are given for the epipoles. Figure 4 shows the mean error over \\(10^{5}\\) independent trials for each noise level. From the figure, we see that the proposed methods are the most robust against noise. Since the two DLT methods, I3 and I5, do not consider the decomposability conditions described in Eqs. (3) and (4), their focal length estimation are sensitive to image noise, which is even worse than the general methods, L6f and M7fk. The proposed methods outperform M7fk in estimation of the fundamental matrix and lens distortion while showing comparable accuracy in the focal length estimation." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.73, + 0.792, + 0.746 + ], + "angle": 0, + "content": "5.3.4 Robustness w.r.t. noise on epipoles" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.892, + 0.903 + ], + "angle": 0, + "content": "In this experiment, we studied the noise robustness of the six methods using epipoles: two Ito et al.'s and four proposed methods. We added the Gaussian noise on epipoles varying \\(0 \\leq \\sigma \\leq 2\\) while fixing the image noise as \\(\\sigma = 0.5\\). Figure 5 reports the mean error over \\(10^{5}\\) independent trials for each noise level. The results have similar trends to the previous experiments. Among the proposed methods, P4f and P5fk are more robust to image noise than P2f and P4fk because P4f and P5fk utilizes a single epipole." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13366" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.082, + 0.09, + 0.307, + 0.231 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.327, + 0.09, + 0.554, + 0.231 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.575, + 0.091, + 0.888, + 0.231 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.174, + 0.235, + 0.794, + 0.251 + ], + "angle": 0, + "content": "Figure 4. Mean error w.r.t. the image noise on point correspondences over \\(10^{5}\\) trials for each noise level." + }, + { + "type": "image", + "bbox": [ + 0.082, + 0.264, + 0.307, + 0.404 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.328, + 0.264, + 0.553, + 0.404 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.575, + 0.264, + 0.888, + 0.404 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.215, + 0.409, + 0.752, + 0.424 + ], + "angle": 0, + "content": "Figure 5. Mean error w.r.t. the image noise on epipoles over \\(10^{5}\\) trials for each noise level." + }, + { + "type": "image", + "bbox": [ + 0.113, + 0.451, + 0.441, + 0.61 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.111, + 0.618, + 0.434, + 0.632 + ], + "angle": 0, + "content": "Figure 6. Runtime comparison of the minimal solvers." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.666, + 0.272, + 0.681 + ], + "angle": 0, + "content": "5.3.5 Computational time" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.698, + 0.47, + 0.775 + ], + "angle": 0, + "content": "Figure 6 shows the mean runtime of all methods over \\(10^{6}\\) independent trials. The computational time of the proposed methods is less than 1 msec, which is not as fast as the Ito et al.'s methods, but is still reasonably fast enough for real-time applications." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.797, + 0.188, + 0.812 + ], + "angle": 0, + "content": "5.4. Real data" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.825, + 0.47, + 0.903 + ], + "angle": 0, + "content": "In this experiments, we incorporated each method into RANSAC together with the non-linear refinement to investigate the performance in real data. We excluded L7fk due to its instability and high computational cost shown in the synthetic data experiments in Sec. 5.3." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.448, + 0.608, + 0.462 + ], + "angle": 0, + "content": "5.4.1 Dataset" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.472, + 0.892, + 0.503 + ], + "angle": 0, + "content": "We used two publicly available dataset where multiple cameras are mutually projected:" + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.507, + 0.893, + 0.614 + ], + "angle": 0, + "content": "HumanEva [32] Four RGB cameras with the \\(656 \\times 490\\) resolution are installed in the corners of a room. The intrinsic parameters are calibrated by Zhang's method, then the extrinsics are calculated using Vicon sensors. A single person is asked to do simple actions such as walking, jogging, etc. There are two combinations of mutual camera projections with two epipoles." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.621, + 0.892, + 0.743 + ], + "angle": 0, + "content": "Panoptic studio \\([16]^{2}\\) 30 HD cameras, 480 VGA cameras, and 5 Kinect2 are installed on the walls of a domeshaped studio. Both the intrinsic and extrinsic parameters of all cameras are simultaneously calibrated based on the structure-from-motion. All sensors are used for recording multi-person interactions. There are 20 combinations of a single epipole and 80 combinations of two epipoles in the HD cameras." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.747, + 0.894, + 0.869 + ], + "angle": 0, + "content": "We chose a video sequence from each dataset in which a single person moves around the scene: S2 sequence of HumanEva (Fig. 2a) and dance1 of Panoptic studio (Fig. 2b). Then, 2D human joints on the video frames were detected using OpenPose [7]. The neck and hip joints were selected as the point correspondences because they are less likely to be occluded and are easily observed from any camera. We manually labeled epipole locations in each image." + }, + { + "type": "page_footnote", + "bbox": [ + 0.516, + 0.875, + 0.764, + 0.888 + ], + "angle": 0, + "content": "1http://humaneva.is.tue.mpg.de/" + }, + { + "type": "page_footnote", + "bbox": [ + 0.516, + 0.888, + 0.81, + 0.9 + ], + "angle": 0, + "content": "\\(^{2}\\)http://domedb.perception.cs.cmu.edu/" + }, + { + "type": "list", + "bbox": [ + 0.516, + 0.875, + 0.81, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13367" + } + ], + [ + { + "type": "table", + "bbox": [ + 0.091, + 0.089, + 0.458, + 0.196 + ], + "angle": 0, + "content": "
MethodεRεtεfεkiter.time
L6f28.014.348.80.7812410.25
M7fk29.815.156.11.4628197.69
I332.816.170.00.26920.04
P2f22.711.348.00.26390.03
P3fk24.712.346.91.111460.04
" + }, + { + "type": "table_caption", + "bbox": [ + 0.14, + 0.202, + 0.407, + 0.216 + ], + "angle": 0, + "content": "(a) HumanEva: S2 (2 epipoles, 2 sequences)" + }, + { + "type": "table", + "bbox": [ + 0.084, + 0.217, + 0.465, + 0.324 + ], + "angle": 0, + "content": "
MethodεRεtεfεkiter.time
L6f17.38.518.62.70100002.68
M7fk23.812.219.82.611000033.43
I515.512.430.72.69100000.83
P4f11.36.818.02.68100001.22
P5fk11.26.518.22.09100003.64
" + }, + { + "type": "table_caption", + "bbox": [ + 0.095, + 0.329, + 0.452, + 0.344 + ], + "angle": 0, + "content": "(b) Panoptic studio: dance1 (single epipole, 20 sequences)" + }, + { + "type": "table", + "bbox": [ + 0.086, + 0.344, + 0.462, + 0.451 + ], + "angle": 0, + "content": "
MethodεRεtεfεkiter.time
L6f10.34.919.82.67100001.80
M7fk12.05.920.02.851000024.88
I313.18.033.72.6620010.15
P2f6.12.817.72.663180.04
P3fk6.63.217.91.7224380.40
" + }, + { + "type": "text", + "bbox": [ + 0.105, + 0.456, + 0.442, + 0.471 + ], + "angle": 0, + "content": "(c) Panoptic studio: dance1 (2 epipoles, 80 sequences)" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.474, + 0.47, + 0.529 + ], + "angle": 0, + "content": "Table 2. Quantitative results of real image dataset (best in bold and second-best underlined). iter.: the number of RANSAC iterations, time: the total processing time of RANSAC and the non-linear refinement in seconds." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.556, + 0.27, + 0.571 + ], + "angle": 0, + "content": "5.4.2 Quantitative results" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.582, + 0.47, + 0.764 + ], + "angle": 0, + "content": "For testing the methods, we configured RANSAC to have the threshold by 3 pixels, the confidence by 0.995, and the maximum iteration number by 10000. The random seed was fixed for all methods during a single trial so that the same sample points were drawn. After RANSAC, the nonlinear refinement described in Sec. 3.5 was performed on inliers to polish the camera parameters to be more accurate. The two general solvers, L6f and M7fk, optimized only the symmetric epipolar distance \\(L_{\\mathrm{sym}}\\) in Eq. (29). The rest of the solvers utilizing epipoles employed the total cost function \\(L\\) in Eq. (30) with a weight \\(w = 100 \\times n\\) to balance \\(L_{\\mathrm{sym}}\\) and \\(L_{\\mathrm{epi}}\\) depending on the number of the points \\(n\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.471, + 0.902 + ], + "angle": 0, + "content": "We conducted 100 and 10 trials for each camera pair of S2 and dance1, respectively. Table 2 reports the average values of \\((\\epsilon_{\\mathrm{R}}, \\epsilon_{\\mathrm{t}}, \\epsilon_{f}, \\epsilon_{k})\\), the number of RANSAC iterations, and the total processing time. Comparing Tab. 2a with Tabs. 2b and 2c, we can see that all methods show better scores in dance1 even though two epipoles are available in HumanEva. The person in dance1 is captured in the higher-resolution image than in HumanEva, resulting in higher localization accuracy of the 2D joints." + }, + { + "type": "image", + "bbox": [ + 0.502, + 0.089, + 0.681, + 0.193 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.504, + 0.197, + 0.678, + 0.212 + ], + "angle": 0, + "content": "(a) 2D trajectory of the neck." + }, + { + "type": "image", + "bbox": [ + 0.546, + 0.226, + 0.632, + 0.321 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.551, + 0.327, + 0.631, + 0.34 + ], + "angle": 0, + "content": "(c) Top view." + }, + { + "type": "image", + "bbox": [ + 0.714, + 0.09, + 0.892, + 0.193 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.713, + 0.197, + 0.892, + 0.226 + ], + "angle": 0, + "content": "(b) Reprojection of estimated epipoles (green area in (a))." + }, + { + "type": "image", + "bbox": [ + 0.704, + 0.234, + 0.888, + 0.322 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.751, + 0.327, + 0.835, + 0.339 + ], + "angle": 0, + "content": "(d) Side view." + }, + { + "type": "image_caption", + "bbox": [ + 0.54, + 0.34, + 0.852, + 0.353 + ], + "angle": 0, + "content": "Figure 7. 3D shape reconstruction of HumanEva S2." + }, + { + "type": "image", + "bbox": [ + 0.502, + 0.381, + 0.68, + 0.459 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.504, + 0.465, + 0.677, + 0.479 + ], + "angle": 0, + "content": "(a) 2D trajectory of the neck." + }, + { + "type": "image", + "bbox": [ + 0.714, + 0.381, + 0.891, + 0.46 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.713, + 0.465, + 0.892, + 0.494 + ], + "angle": 0, + "content": "(b) Reprojection of estimated epipoles. (green area in (a))" + }, + { + "type": "image", + "bbox": [ + 0.522, + 0.493, + 0.663, + 0.602 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.55, + 0.608, + 0.631, + 0.621 + ], + "angle": 0, + "content": "(c) Top view." + }, + { + "type": "image", + "bbox": [ + 0.717, + 0.51, + 0.89, + 0.602 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.761, + 0.608, + 0.845, + 0.62 + ], + "angle": 0, + "content": "(d) Side view." + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.621, + 0.874, + 0.635 + ], + "angle": 0, + "content": "Figure 8. 3D shape reconstruction of Panoptic studio dance1." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.674, + 0.892, + 0.902 + ], + "angle": 0, + "content": "Table 2 indicates that the proposed solvers outperform the conventional methods in either case of one or two epipoles. The proposed solvers show the best or the second-best scores in most evaluation criteria. For example, P2f and P4f are more than 100 times faster than M7fk while achieving lower estimation errors. Although P2f and P4f does not estimate the radial distortion \\( k \\) in RANSAC, the non-linear refinement successfully converges to an accurate solution of \\( k \\) due to a good initial guess of \\( \\mathbf{F} \\) and \\( \\mathbf{f} \\). On the other hand, in spite of the use of epipoles, I3 and I5 are inferior to the general solvers L6f and M7fk. As reported in Sec. 5.3, two Ito's methods are sensitive to image noise. According to the above observations, we can conclude that satisfying the decomposability conditions, Eqs. (3) and (4), significantly improves the estimation accuracy even with known epipoles." + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "13368" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.077, + 0.092, + 0.262, + 0.108 + ], + "angle": 0, + "content": "5.4.3 Qualitative results" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.115, + 0.473, + 0.298 + ], + "angle": 0, + "content": "Figures 7 and 8 visualize a 3D shape reconstruction of S2 and dance1, respectively. For ease of viewing, only neck joints are shown in both 2D and 3D images. We plotted the position of estimated epipoles over 30 independent trials in Figs. 7b and 8b. The P3fk's epipole and the ground-truth overlap so closely that the difference is not visible. On the other hand, the camera motion given by M7fk has large errors and the epipole is estimated on a different place in each trial. This is consistent with the result in Tab. 2 where the proposed methods have the smallest motion errors. Also, we can visually validate that P3fk reconstructs a 3D shape more accurately than M7fk in Figs. 7c, 7d, 8c and 8d." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.309, + 0.342, + 0.325 + ], + "angle": 0, + "content": "6. Limitations and future work" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.334, + 0.473, + 0.59 + ], + "angle": 0, + "content": "One of the limitations is that epipole positions are manually annotated. This is not a critical issue in data set creation (Figs. 2a and 2b) because device installations and data capturing spend time dominantly. However, a fast-automatic epipole detector is required to use the proposed method in real-time applications such as multi-agent Visual-SLAM [28, 29, 36] shown in Figs. 2c and 2d. Although direct epipole estimation has been studied for several decades [2, 8, 22], unfortunately it cannot be said as active nor extensive. We think that the manual labeling is merely a current limitation, which can be resolved by future effort in the computer vision community. For instance, a quick workaround is to place a camera at the center of a colored sphere or circle and detect the camera's center in images by ellipse fitting. Alternatively, there are more sophisticated ways that use wifi/radio waves or IMUs to find the relative locations between devices in 3D space [3]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.592, + 0.473, + 0.698 + ], + "angle": 0, + "content": "Another future work is to extend the proposed approach to multi-view geometry, just as Sato [30] extended Ito et al.'s DLT method [14] for obtaining a trifocal or quadrifocal tensor. Combining the multi-view extension with an automatic epipole detector, we can expect that the proposed approach stabilizes multi-agent Visual-SLAM with wide baselines for large-scale scene." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.71, + 0.196, + 0.725 + ], + "angle": 0, + "content": "7. Conclusion" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.473, + 0.903 + ], + "angle": 0, + "content": "We have presented four minimal solutions to the uncalibrated two-view geometry where one or two epipoles are visible in the image plane. All solvers are manually formulated as higher-order polynomials in a single variable without an automatic Gröbner basis generator. We briefly discussed the degenerate conditions and showed several examples where the proposed solvers are feasible but not the conventional methods. In the experiments, we first compared the proposed solvers with the conventional methods in the numerical stability and robustness against image noise using synthetic data. Then, we demonstrated that the proposed" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.895, + 0.244 + ], + "angle": 0, + "content": "solvers successfully stabilize the structure-from-motion using human joints as point correspondences, which are noisy and less accurate than image feature points. Through these experiments, the proposed solvers outperform the conventional methods in estimation accuracy with maintaining computational efficiency. Finally, we discussed the current limitations of the proposed approach and future work to be applicable in real-time applications. We hope this paper will motivate the computer vision community to develop automatic epipole detectors more extensively." + }, + { + "type": "title", + "bbox": [ + 0.501, + 0.256, + 0.597, + 0.272 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.508, + 0.28, + 0.892, + 0.336 + ], + "angle": 0, + "content": "[1] Sameer Agarwal, Yasutaka Furukawa, Noah Snavely, Ian Simon, Brian Curless, Steven M Seitz, and Richard Szeliski. Building rome in a day. Communications of the ACM, 54(10):105-112, 2011. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.338, + 0.894, + 0.406 + ], + "angle": 0, + "content": "[2] Farhoosh Alghabi and Mohsen Soryani. Direct computation of epipoles using two pairs of point-line correspondences. In 2008 Second International Symposium on Intelligent Information Technology Application, volume 3, pages 486-489, 2008. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.409, + 0.892, + 0.464 + ], + "angle": 0, + "content": "[3] Safar M Asaad and Halgurd S Maghdid. A comprehensive review of indoor/outdoor localization solutions in IoT era: Research challenges and future perspectives. Computer Networks, page 109041, 2022. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.465, + 0.892, + 0.519 + ], + "angle": 0, + "content": "[4] Shai Avidan and Amnon Shashua. Novel view synthesis in tensor space. In Proceedings of IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 1034-1040. IEEE, 1997. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.521, + 0.892, + 0.577 + ], + "angle": 0, + "content": "[5] GN Newsam DQ Huynh MJ Brooks and HP Pan. Recovering unknown focal lengths in self-calibration: An essentially linear algorithm and degenerate configurations. In Proc. ISPRS-Congress, volume 31, pages 575-580. Citeseer, 1996. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.578, + 0.892, + 0.647 + ], + "angle": 0, + "content": "[6] Cesar Cadena, Luca Carlone, Henry Carrillo, Yasir Latif, Davide Scaramuzza, José Neira, Ian Reid, and John J Leonard. Past, present, and future of simultaneous localization and mapping: Toward the robust-perception age. IEEE Transactions on robotics, 32(6):1309-1332, 2016. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.649, + 0.892, + 0.703 + ], + "angle": 0, + "content": "[7] Z. Cao, G. Hidalgo Martinez, T. Simon, S. Wei, and Y. A. Sheikh. Openpose: Realtime multi-person 2d pose estimation using part affinity fields. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2019. 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.705, + 0.892, + 0.773 + ], + "angle": 0, + "content": "[8] Huiqin Chen, Emanuel Aldea, and Sylvie Le Hégarat-Mascle. Determining epipole location integrity by multimodal sampling. In 2019 16th IEEE International Conference on Advanced Video and Signal Based Surveillance (AVSS), pages 1-8. IEEE, 2019. 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.509, + 0.776, + 0.892, + 0.83 + ], + "angle": 0, + "content": "[9] Martin A Fischler and Robert C Bolles. Random sample consensus: a paradigm for model fitting with applications to image analysis and automated cartography. Communications of the ACM, 24(6):381-395, 1981. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.832, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[10] Andrew W Fitzgibbon. Simultaneous linear estimation of multiple view geometry and lens distortion. In Proceedings of the 2001 IEEE Computer Society Conference on Computer Vision and Pattern Recognition. CVPR 2001, volume 1, pages I-I. IEEE, 2001. 2" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.28, + 0.894, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "13369" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.134 + ], + "angle": 0, + "content": "[11] Richard I. Hartley and Andrew Zisserman. Multiple View Geometry in Computer Vision. Cambridge University Press, ISBN: 0521540518, second edition, 2004. 1, 2, 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.136, + 0.47, + 0.19 + ], + "angle": 0, + "content": "[12] Uwe Helmke, Knut Hüper, Pei Yean Lee, and John Moore. Essential matrix estimation using gauss-newton iterations on a manifold. International Journal of Computer Vision, 74(2):117-136, 2007. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.192, + 0.469, + 0.22 + ], + "angle": 0, + "content": "[13] Berthold KP Horn. Recovering baseline and orientation from essential matrix. J. Opt. Soc. Am, 110, 1990. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.222, + 0.469, + 0.276 + ], + "angle": 0, + "content": "[14] M. Ito, T. Sugimura, and J. Sato. Recovering structures and motions from mutual projection of cameras. In 2002 International Conference on Pattern Recognition, volume 3, pages 676-679 vol.3, 2002. 1, 5, 6, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.278, + 0.469, + 0.333 + ], + "angle": 0, + "content": "[15] Fangyuan Jiang, Yubin Kuang, Jan Erik Solem, and Kalle Åström. A minimal solution to relative pose with unknown focal length and radial distortion. In Asian Conference on Computer Vision, pages 443-456. Springer, 2014. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.335, + 0.469, + 0.417 + ], + "angle": 0, + "content": "[16] Hanbyul Joo, Hao Liu, Lei Tan, Lin Gui, Bart Nabbe, Iain Matthews, Takeo Kanade, Shohei Nobuhara, and Yaser Sheikh. Panoptic studio: A massively multiview system for social motion capture. In Proceedings of the IEEE International Conference on Computer Vision, pages 3334-3342, 2015. 2, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.42, + 0.469, + 0.474 + ], + "angle": 0, + "content": "[17] Kenichi Kanatani and Chikara Matsunaga. Closed-form expression for focal lengths from the fundamental matrix. In Proc. 4th Asian Conf. Comput. Vision, volume 1, pages 128-133. CiteSeer, 2000. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.477, + 0.469, + 0.545 + ], + "angle": 0, + "content": "[18] Yubin Kuang, Jan E Solem, Fredrik Kahl, and Kalle Astrom. Minimal solvers for relative pose with a single unknown radial distortion. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 33-40, 2014. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.548, + 0.469, + 0.616 + ], + "angle": 0, + "content": "[19] Zuzana Kukelova, Martin Bujnak, and Tomas Pajdla. Polynomial eigenvalue solutions to the 5-pt and 6-pt relative pose problems. In Proceedings of the British Machine Vision Conference, pages 56.1-56.10. BMVA Press, 2008. doi:10.5244/C.22.56.1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.618, + 0.469, + 0.686 + ], + "angle": 0, + "content": "[20] Zuzana Kukelova, Joe Kileel, Bernd Sturmfels, and Tomas Pajdla. A clever elimination strategy for efficient minimal solvers. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4912-4921, 2017. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.689, + 0.469, + 0.757 + ], + "angle": 0, + "content": "[21] Viktor Larsson, Kalle Astrom, and Magnus Oskarsson. Efficient solvers for minimal problems by syzygy-based reduction. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 820-829, 2017. 1, 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.759, + 0.469, + 0.814 + ], + "angle": 0, + "content": "[22] Jonathan Lawn and Roberto Cipolla. Epipole estimation using affine motion parallax. In Proceedings of the British Machine Vision Conference, pages 38.1-38.10. BMVA Press, 1993. doi:10.5244/C.7.38.9" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.817, + 0.469, + 0.858 + ], + "angle": 0, + "content": "[23] Hongdong Li. A simple solution to the six-point two-view focal-length problem. In European Conference on Computer Vision, pages 200-213. Springer, 2006. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.86, + 0.469, + 0.901 + ], + "angle": 0, + "content": "[24] Evgeniy Martyushev, Jana Vrablikova, and Tomas Pajdla. Optimizing elimination templates by greedy parameter search. In Proceedings of the IEEE/CVF Conference" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.47, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.535, + 0.093, + 0.892, + 0.12 + ], + "angle": 0, + "content": "on Computer Vision and Pattern Recognition, pages 15754-15764, 2022. 5, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.122, + 0.892, + 0.19 + ], + "angle": 0, + "content": "[25] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. In European conference on computer vision, pages 405-421. Springer, 2020. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.192, + 0.892, + 0.246 + ], + "angle": 0, + "content": "[26] Raul Mur-Artal, Jose Maria Martinez Montiel, and Juan D Tardos. Orb-slam: a versatile and accurate monocular slam system. IEEE transactions on robotics, 31(5):1147-1163, 2015. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.249, + 0.892, + 0.29 + ], + "angle": 0, + "content": "[27] David Nister and Frederik Schaffalitzky. Four points in two or three calibrated views: Theory and practice. International Journal of Computer Vision, 67:211-231, 2006. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.292, + 0.892, + 0.36 + ], + "angle": 0, + "content": "[28] Jacob M Perron, Rui Huang, Jack Thomas, Lingkang Zhang, Ping Tan, and Richard T Vaughan. Orbiting a moving target with multi-robot collaborative visual slam. In Proceedings of the Workshop on Multi-View Geometry in Robotics (MVI-GRO), Rome, Italy, pages 1339–1344, 2015. 2, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.362, + 0.892, + 0.431 + ], + "angle": 0, + "content": "[29] Thomas Pollok and Eduardo Monari. A visual slam-based approach for calibration of distributed camera networks. In 2016 13th IEEE International Conference on Advanced Video and Signal Based Surveillance (AVSS), pages 429-437, 2016. 2, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.433, + 0.892, + 0.473 + ], + "angle": 0, + "content": "[30] Jun Sato. Recovering multiple view geometry from mutual projections of multiple cameras. International Journal of Computer Vision, 66(2):123-140, 2006. 1, 5, 9" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.476, + 0.892, + 0.517 + ], + "angle": 0, + "content": "[31] Johannes Lutz Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In Conference on Computer Vision and Pattern Recognition (CVPR), 2016. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.518, + 0.892, + 0.585 + ], + "angle": 0, + "content": "[32] Leonid Sigal, Alexandru O Balan, and Michael J Black. Humaneva: Synchronized video and motion capture dataset and baseline algorithm for evaluation of articulated human motion. International journal of computer vision, 87(1):4-27, 2010. 2, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.588, + 0.892, + 0.63 + ], + "angle": 0, + "content": "[33] Carsten Steger. Estimating the fundamental matrix under pure translation and radial distortion. ISPRS Journal of Photogrammetry and Remote Sensing, 74:202-217, 2012. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.631, + 0.892, + 0.686 + ], + "angle": 0, + "content": "[34] Henrik Stewénius, David Nister, Fredrik Kahl, and Frederik Schaffalitzky. A minimal solution for relative pose with unknown focal length. Image and Vision Computing, 26(7):871-877, 2008. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.688, + 0.892, + 0.742 + ], + "angle": 0, + "content": "[35] Changchang Wu. Critical configurations for radial distortion self-calibration. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 25-32, 2014. 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.744, + 0.892, + 0.799 + ], + "angle": 0, + "content": "[36] Danping Zou and Ping Tan. Coslam: Collaborative visual slam in dynamic environments. IEEE Transactions on Pattern Analysis and Machine Intelligence, 35(2):354-366, 2013. 2, 9" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.799 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.481, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "13370" + } + ] +] \ No newline at end of file diff --git a/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/1ff0de2c-2b50-437f-a3e0-afb03703f817_origin.pdf b/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/1ff0de2c-2b50-437f-a3e0-afb03703f817_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..0952c7365c193b27008f39e3281ea9306107233e --- /dev/null +++ b/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/1ff0de2c-2b50-437f-a3e0-afb03703f817_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:932be346d0cd46594bee48f3986500bde74817ef33e36c240d6e0ef207022883 +size 2299919 diff --git a/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/full.md b/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/full.md new file mode 100644 index 0000000000000000000000000000000000000000..103d6fefa082ad6235bc510b0fbe8c2d1ff10a7b --- /dev/null +++ b/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/full.md @@ -0,0 +1,492 @@ +# Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles + +Gaku Nakano + +NEC Corporation + +1753 Shimonumabe, Kawasaki, Japan + +g-nakano@nec.com + +# Abstract + +This paper proposes minimal solutions to uncalibrated two-view geometry with known epipoles. Exploiting the epipoles, we can reduce the number of point correspondences needed to find the fundamental matrix together with the intrinsic parameters: the focal length and the radial lens distortion. We define four cases by the number of available epipoles and unknown intrinsic parameters, then derive a closed-form solution for each case formulated as a higher-order polynomial in a single variable. The proposed solvers are more numerically stable and faster by orders of magnitude than the conventional 6- or 7-point algorithms. Moreover, we demonstrate by experiments on the human pose dataset that the proposed method can solve two-view geometry even with 2D human pose, of which point localization is noisier than general feature point detectors. + +# 1. Introduction + +Solving the two-view geometry of uncalibrated cameras is one of the basic tasks for many computer vision applications such as the structure-from-motion [1, 31], Visual-SLAM [6, 26], and novel view synthesis [4, 25]. The goal of this problem is to find the fundamental matrix and the intrinsic parameters of the two cameras from point correspondences. Since point correspondences are generally contaminated by outliers, many efforts have been devoted to develop efficient and numerically stable solvers that can be incorporated into RANSAC [9] to extract a set of inlier point pairs. + +It is known that the fundamental matrix with an unknown focal length and known principal points can be determined by six point correspondences. Stewenius et al. [34] first developed a minimal solution to this problem by manually deriving Gröbner basis. Then, other methods were proposed based on various approaches, e.g. the hidden variable technique [23], the polynomial eigenvalue problem [19], the automatic generator [21]. Following the success of the 6-point algorithms, research interests have been expanded to deal with the radial lens distortion. Jiang et al. [15] and + +Kuang et al. [18] showed that the fundamental matrix with both unknown focal length and unknown radial distortion can be solved by seven point correspondences. However, with more intrinsic parameters to be estimated, new issues arise in terms of numerical stability and computational efficiency. The root cause is that those methods assume general conditions with no restrictions on the camera motion and thus cannot reduce the number of point correspondences. + +To address the above issue, we assume that two cameras are mutually observed, as shown in Fig. 1. This is not a rare and limited situation but occurs in real applications. For example, multiple cameras are installed to capture human behaviors from $360^{\circ}$ views in dataset creation (Figs. 2a and 2b). In dynamic scenes such as multi-agent Visual-SLAM, robots collaboratively create a single map of a wide area (Fig. 2c). Visual-SLAM can also be applied to calibrate camera networks consisting of fixed and moving cameras (Fig. 2d). In those scenarios, epipoles or 2D positions of the camera center are directly obtainable from images. Epipoles constrain a fundamental matrix to be rank-deficient, thus reducing the number of point correspondences. Nistér [27] showed a theory for finding a relative rotation of calibrated cameras with a single epipole. Ito et al. [14] utilized epipole(s) for fundamental matrix estimation, then Sato [30] generalized it to three- and four-view geometry. However, both methods are based on the DLT algorithm [11], thus not minimal solutions. They also do not address how to find the intrinsic parameters. + +In this paper, we propose minimal solutions utilizing epipole(s) to determine a fundamental matrix with unknown intrinsic camera parameters: focal length and radial lens distortion. The proposed method has four variations depending on the number of available epipoles and the number of unknown parameters to be estimated. Moreover, we introduce a simple regularization term to fix the epipoles during the non-linear optimization, which is conducted on inliers after RANSAC. Through exhaustive experiments, we show that the proposed algorithms provide more reliable estimations than the conventional methods while achieving a significant acceleration by orders of magnitude. + +![](images/d1df319f1136e9f5f6e4398f5f5a1a38be9a6888e895be889fa1feda70d86891.jpg) + +![](images/e8a164bc1c660ac212b69445da864d9b3d7ce00f9a1c207bc94b5d25f882ebc9.jpg) +(a) Single epipole case. The projection of the second camera is observed as $\mathbf{e}$ in the first camera. +(b) Two epipoles case. The two cameras are mutually observed as e and $\mathbf{e}^{\prime}$ in each image. + +![](images/cac7d0c5b923cf282edfbdebd8fc016dedb70a77078471817be11ab33ea4787f.jpg) + +![](images/b8d7c984d1775a217687fa17aede034ddedd54c5d2fc9df3febed38928dbe64e.jpg) +Figure 1. Two-view geometry with known epipoles. + +![](images/dd78af87cf180d31da669a0e2ef406f1fd51f4c99c0952605a6bc53d2308d298.jpg) +(a) HumanEva [32] +(c) Collaborative Visual- (d) SLAM-based calibration for surveilSLAM [28, 36] lance and moving cameras [29] +Figure 2. Mutual camera projections in applications. (a)-(b): Human pose dataset. (c)-(d): Multi-agent Visual-SLAM. + +![](images/b4817c98b48328fb9c351e75f0aa0cd0f927873ee2ac00dae49a68999ff9a749.jpg) +(b) Panoptic studio dataset [16] + +# 2. Uncalibrated two-view geometry + +This section describes the theoretical background of two-view geometry for uncalibrated cameras. We represent 2D points as their homogeneous coordinates, i.e. $\mathbf{m} = [u,v,1]^{\mathrm{T}}$ , and assume a pinhole camera model whose intrinsic parameters are partially known: the principal point is approximated by the image center; the skewness is zero. Solving uncalibrated two-view geometry is to find the focal length $f$ and the radial lens distortion $k$ as well as the relative rotation $\mathbb{R}$ and translation $\mathfrak{t}$ between the two cameras. + +Given $n$ pairs of a 2D point correspondence $\{\mathbf{m}_i \leftrightarrow \mathbf{m}_i'\}$ between the two cameras, each point pair is constrained by a $3 \times 3$ fundamental matrix $\mathbf{F}$ : + +$$ +\mathbf {m} _ {i} ^ {\prime} ^ {\top} \mathbf {F m} _ {i} = \left(\mathbf {m} _ {i} ^ {\prime} \otimes \mathbf {m} _ {i}\right) ^ {\top} \mathbf {f} = 0, \tag {1} +$$ + +where $\otimes$ denotes the Kronecker product and $\mathbf{f}$ is a 9-dim vector representation of $\mathbf{F}$ . + +Epipoles, $\mathbf{e} = [x,y,1]^{\top}$ and $\mathbf{e}' = [x',y',1]^{\top}$ , are the 2D projections of the image center of one camera onto the image plane of the other camera, which satisfy + +$$ +\mathbf {F} \mathbf {e} = \mathbf {F} ^ {\top} \mathbf {e} ^ {\prime} = \mathbf {0}. \tag {2} +$$ + +Equation (2) leads to one of the constraints on $\mathbf{F}$ , i.e. $\operatorname*{det}(\mathbf{F}) = 0$ . Thus, $\mathbf{F}$ is of rank two. + +When the two cameras can be assumed to have the same focal length $f$ , another constraint is given by + +$$ +2 F Q F ^ {\top} Q F Q - \operatorname {t r} \left(F Q F ^ {\top} Q\right) F Q = 0, \tag {3} +$$ + +where $\mathbb{Q} = \mathrm{diag}(f^2, f^2, 1)$ . Equation (3) is the necessary and sufficient conditions to recover $\mathbf{R}$ and $\mathbf{t}$ by decomposing $\mathbf{F}$ . Eliminating $f$ , we can rewrite Eq. (3) in a closed-form w.r.t. $\mathbf{F}$ [20] as follows: + +$$ +\begin{array}{l} h (\mathbf {F}) = F _ {1 1} F _ {1 3} ^ {3} F _ {3 1} + F _ {1 3} ^ {2} F _ {2 1} F _ {2 3} F _ {3 1} + F _ {1 1} F _ {1 3} F _ {2 3} ^ {2} F _ {3 1} \\ + F _ {2 1} F _ {2 3} ^ {3} F _ {3 1} - F _ {1 1} F _ {1 3} F _ {3 1} ^ {3} - F _ {2 1} F _ {2 3} F _ {3 1} ^ {3} + F _ {1 2} F _ {1 3} ^ {3} F _ {3 2} \\ + F _ {1 3} ^ {2} F _ {2 2} F _ {2 3} F _ {3 2} + F _ {1 2} F _ {1 3} F _ {2 3} ^ {2} F _ {3 2} + F _ {2 2} F _ {2 3} ^ {3} F _ {3 2} \\ - F _ {1 2} F _ {1 3} F _ {3 1} ^ {2} F _ {3 2} - F _ {2 2} F _ {2 3} F _ {3 1} ^ {2} F _ {3 2} - F _ {1 1} F _ {1 3} F _ {3 1} F _ {3 2} ^ {2} \\ - F _ {2 1} F _ {2 3} F _ {3 1} F _ {3 2} ^ {2} - F _ {1 2} F _ {1 3} F _ {3 2} ^ {3} - F _ {2 2} F _ {2 3} F _ {3 2} ^ {3} \tag {4} \\ - F _ {1 1} ^ {2} F _ {1 3} ^ {2} F _ {3 3} - F _ {1 2} ^ {2} F _ {1 3} ^ {2} F _ {3 3} - 2 F _ {1 1} F _ {1 3} F _ {2 1} F _ {2 3} F _ {3 3} \\ - 2 F _ {1 2} F _ {1 3} F _ {2 2} F _ {2 3} F _ {3 3} - F _ {2 1} ^ {2} F _ {2 3} ^ {2} F _ {3 3} - F _ {2 2} ^ {2} F _ {2 3} ^ {2} F _ {3 3} \\ + F _ {1 1} ^ {2} F _ {3 1} ^ {2} F _ {3 3} + F _ {2 1} ^ {2} F _ {3 1} ^ {2} F _ {3 3} + 2 F _ {1 1} F _ {1 2} F _ {3 1} F _ {3 2} F _ {3 3} \\ + 2 F _ {2 1} F _ {2 2} F _ {3 1} F _ {3 2} F _ {3 3} + F _ {1 2} ^ {2} F _ {3 2} ^ {2} F _ {3 3} + F _ {2 2} ^ {2} F _ {3 2} ^ {2} F _ {3 3} = 0, \\ \end{array} +$$ + +where $F_{ij}$ denotes the $(i,j)$ element of $\mathbf{F}$ . + +Once we obtain an $\mathbf{F}$ such that $\operatorname*{det}(\mathbb{F}) = 0$ and Eq. (3) (or Eq. (4)), the focal length $f$ can be computed in a closed-form [20]: + +$$ +\begin{array}{l} F _ {1 2} F _ {1 3} F _ {3 3} ^ {2} + F _ {2 2} F _ {2 3} F _ {3 3} ^ {2} \\ f ^ {2} = \frac {- F _ {1 3} ^ {2} F _ {3 2} F _ {3 3} - F _ {2 3} ^ {2} F _ {3 2} F _ {3 3}}{F _ {1 1} F _ {1 3} F _ {3 1} F _ {3 2} + F _ {2 1} F _ {2 3} F _ {3 1} F _ {3 2} + F _ {1 2} F _ {1 3} F _ {3 2} ^ {2}}. \tag {5} \\ + F _ {2 2} F _ {2 3} F _ {3 2} ^ {2} - F _ {1 2} ^ {2} F _ {3 2} F _ {3 3} - F _ {2 2} ^ {2} F _ {3 2} F _ {3 3} \\ - F _ {1 1} F _ {1 2} F _ {3 1} F _ {3 3} - F _ {2 1} F _ {2 2} F _ {3 1} F _ {3 3} \\ \end{array} +$$ + +It is well known that the relative motion, $\mathbf{R}$ and $\mathbf{t}$ , can be obtained by using a singular value decomposition [11] or a closed-form method [13]. + +If the cameras have a wide angle lens with a radial distortion parameter $k$ , a 2D point $\mathbf{m}$ is observed as a radially distorted point $\hat{\mathbf{m}}$ . The relation can be written by using the division model [10]: + +$$ +\mathbf {m} = \frac {1}{1 + k r} \hat {\mathbf {m}} \propto \left[ \begin{array}{c} \hat {u} \\ \hat {v} \\ 1 + k r \end{array} \right], \tag {6} +$$ + +where $r = \hat{u}^2 +\hat{v}^2$ . Hereafter, we use the hat symbol $\hat{\cdot}$ to express radially distorted values. + +# 3. Finding F-matrix with known epipoles + +In this section, we propose four different algorithms depending on the number of unknown intrinsic parameters and the number of known epipoles. The basic strategy commonly used in all methods is to parameterize a fundamental matrix $\mathbf{F}$ as a linear combination of the null space of a coefficient matrix computed from epipoles and point correspondences. We reduce the number of unknown variables to one and employ Eq. (4) to lead to a higher-order polynomial equation of the single variable. The fundamental matrix $\mathbf{F}$ is obtained by substituting the real roots of the polynomial equation into the linear combination of the null space. The null space is derived from the epipoles, and Eq. (4) is used for the root finding, therefore, both the intrinsic and extrinsic parameters can be recovered from the computed $\mathbf{F}$ . + +# 3.1. 2-pt algorithm for $\mathbf{F} + \mathbf{f}$ with two epipoles + +We start with the simplest case where two epipoles $\mathbf{e}$ and $\mathbf{e}'$ are observed by each camera with an unknown focal length $f$ but no lens distortion. If we define the $3 \times 3$ identity matrix by $\mathbf{I}$ and a $6 \times 9$ matrix $\mathbb{N}_1$ by + +$$ +\mathrm {N} _ {1} = \left[ \begin{array}{c c c} \mathbf {e} ^ {\mathrm {T}} & & \\ & \mathbf {e} ^ {\mathrm {T}} & \\ & & \mathbf {e} ^ {\mathrm {T}} \\ x ^ {\prime} \mathrm {I} & y ^ {\prime} \mathrm {I} & \mathrm {I} \end{array} \right], \tag {7} +$$ + +Eq. (2) can be written in the form + +$$ +\mathrm {N} _ {1} \mathbf {f} = \mathbf {0}. \tag {8} +$$ + +Here, $\mathbb{N}_1$ is of size $6\times 9$ but its row rank is only five. + +Utilizing two point correspondences, a $8 \times 9$ coefficient matrix $\mathbb{M}_1$ is given by + +$$ +\mathrm {M} _ {1} = \left[ \begin{array}{c} \mathrm {N} _ {1} \\ \left(\mathbf {m} _ {1} ^ {\prime} \otimes \mathbf {m} _ {1}\right) ^ {\mathsf {T}} \\ \left(\mathbf {m} _ {2} ^ {\prime} \otimes \mathbf {m} _ {2}\right) ^ {\mathsf {T}} \end{array} \right]. \tag {9} +$$ + +Then, we have + +$$ +\mathrm {M} _ {1} \mathbf {f} = \mathbf {0}. \tag {10} +$$ + +Since the row rank of $\mathsf{M}_1$ is seven, $\mathbf{f}$ can be parameterized by a linear combination of two null vectors $\mathbf{v}_1$ , $\mathbf{v}_2$ of $\mathsf{M}_1$ : + +$$ +\mathbf {f} = \alpha \mathbf {v} _ {2} + \mathbf {v} _ {1}. \tag {11} +$$ + +Substituting Eq. (11) into Eq. (4), we obtain a fifth-order equation for the single variable $\alpha$ , which is represented by + +$$ +h (\mathbb {F} (\alpha)) = c _ {5} \alpha^ {5} + c _ {4} \alpha^ {4} + c _ {3} \alpha^ {3} + c _ {2} \alpha^ {2} + c _ {1} \alpha + c _ {0} = 0. \tag {12} +$$ + +Once we found the roots of Eq. (12), the fundamental matrix $\mathbf{F}$ is then obtained from Eq. (11). This algorithm gives at most five solutions. + +# 3.2. 4-pt algorithm for $\mathbf{F} + \mathbf{f}$ with single epipole + +When one of the two epipoles is only available, we can solve the $\mathbf{F} + f$ problem by adding more two point correspondences. Using four point correspondences together with the single epipole $\mathbf{e}$ , we can construct a $7 \times 9$ coefficient matrix $\mathbb{M}_2$ by + +$$ +\mathrm {M} _ {2} = \left[ \begin{array}{c c c} \mathbf {e} ^ {\top} & & \\ & \mathbf {e} ^ {\top} & \\ & & \mathbf {e} ^ {\top} \\ \left(\mathbf {m} _ {1} ^ {\prime} \otimes \mathbf {m} _ {1}\right) ^ {\top} & & \\ & \vdots & \\ \left(\mathbf {m} _ {4} ^ {\prime} \otimes \mathbf {m} _ {4}\right) ^ {\top} & & \end{array} \right], \tag {13} +$$ + +which satisfies + +$$ +\mathrm {M} _ {2} \mathbf {f} = \mathbf {0}. \tag {14} +$$ + +The row rank of $\mathbb{M}_2$ is seven, which is identical to $\mathbb{M}_1$ . Consequently, we can find $\mathbb{F}$ using exactly the same approach as in Eqs. (11) and (12). The number of the real solutions of this algorithm is at most five. + +# 3.3. 3-pt algorithm for $\mathbf{F} + \mathbf{f} + \mathbf{k}$ with two epipoles + +We address a more complicated problem where a radial distortion parameter $k$ is additionally unknown. Since we have two epipoles in this case, this problem can be solved using three point correspondences. + +In this problem, the epipoles, $\hat{\mathbf{e}}$ and $\hat{\mathbf{e}}^{\prime}$ , are observed in the distorted image coordinates, as with the point correspondences $\hat{\mathbf{m}}$ . Using Eq. (6), we can represent the undistorted epipoles, $\mathbf{e}$ and $\mathbf{e}^{\prime}$ , as + +$$ +\mathbf {e} = \frac {1}{1 + k z} \hat {\mathbf {e}} \propto \left[ \begin{array}{c} \hat {x} \\ \hat {y} \\ 1 + k z \end{array} \right], \tag {15} +$$ + +$$ +\mathbf {e} ^ {\prime} = \frac {1}{1 + k z ^ {\prime}} \hat {\mathbf {e}} ^ {\prime} \propto \left[ \begin{array}{c} \hat {x} ^ {\prime} \\ \hat {y} ^ {\prime} \\ 1 + k z ^ {\prime} \end{array} \right], +$$ + +where $z = \hat{x}^2 +\hat{y}^2$ and $z^{\prime} = \hat{x}^{\prime 2} + \hat{y}^{\prime 2}$ . Note that the radial distortion $k$ is an unknown parameter. + +Similar to Eqs. (7) and (8), we can rewrite Eq. (2) by + +$$ +\mathrm {N} _ {2} \mathbf {f} = \mathbf {0}, \tag {16} +$$ + +where + +$$ +\mathrm {N} _ {2} = \left[ \begin{array}{c c c} \mathbf {e} ^ {\top} & & \\ & \mathbf {e} ^ {\top} & \\ & & \mathbf {e} ^ {\top} \\ \hat {x} ^ {\prime} \mathrm {I} & \hat {y} ^ {\prime} \mathrm {I} & (1 + k z ^ {\prime}) \mathrm {I} \end{array} \right]. \tag {17} +$$ + +The null space of $\mathbb{N}_2$ can be symbolically given by + +$$ +\mathsf {V} _ {1} = +$$ + +$$ +\left[ \begin{array}{c c c c} \hat {y} \hat {y} ^ {\prime} & \hat {y} ^ {\prime} (1 + k z) & \hat {y} (1 + k z ^ {\prime}) & (1 + k z) (1 + k z ^ {\prime}) \\ - \hat {x} \hat {y} ^ {\prime} & 0 & - \hat {x} (1 + k z ^ {\prime}) & 0 \\ 0 & - \hat {x} \hat {y} ^ {\prime} & 0 & - \hat {x} (1 + k z ^ {\prime}) \\ - \hat {x} ^ {\prime} \hat {y} & - \hat {x} ^ {\prime} (1 + k z) & 0 & 0 \\ \hat {x} \hat {x} ^ {\prime} & 0 & 0 & 0 \\ 0 & \hat {x} \hat {x} ^ {\prime} & 0 & 0 \\ 0 & 0 & - \hat {x} ^ {\prime} \hat {y} & - \hat {x} ^ {\prime} (1 + k z) \\ 0 & 0 & \hat {x} \hat {x} ^ {\prime} & 0 \\ 0 & 0 & 0 & \hat {x} \hat {x} ^ {\prime} \end{array} \right] \tag {18} +$$ + +Thus, the fundamental matrix can be represented as a linear combination of the column vectors of $\mathrm{V}_1$ , i.e. + +$$ +\mathbf {f} = \mathrm {V} _ {1} \boldsymbol {\alpha} _ {1}, \tag {19} +$$ + +where $\alpha_{1}$ is a 4-dim vector. + +We now have three point correspondences, which satisfy $(\mathbf{m}_i' \otimes \mathbf{m}_i)^\top \mathbf{f} = 0$ . If we define a $3 \times 4$ matrix $\mathsf{G}_1$ by + +$$ +\mathbf {G} _ {1} = \left[ \begin{array}{l} \left(\mathbf {m} _ {1} ^ {\prime} \otimes \mathbf {m} _ {1}\right) ^ {\mathrm {T}} \\ \left(\mathbf {m} _ {2} ^ {\prime} \otimes \mathbf {m} _ {2}\right) ^ {\mathrm {T}} \\ \left(\mathbf {m} _ {3} ^ {\prime} \otimes \mathbf {m} _ {3}\right) ^ {\mathrm {T}} \end{array} \right] \mathrm {V} _ {1}, \tag {20} +$$ + +we obtain + +$$ +\left[ \begin{array}{l} \left(\mathbf {m} _ {1} ^ {\prime} \otimes \mathbf {m} _ {1}\right) ^ {\mathsf {T}} \\ \left(\mathbf {m} _ {2} ^ {\prime} \otimes \mathbf {m} _ {2}\right) ^ {\mathsf {T}} \\ \left(\mathbf {m} _ {3} ^ {\prime} \otimes \mathbf {m} _ {3}\right) ^ {\mathsf {T}} \end{array} \right] \mathbf {f} = \mathbb {G} _ {1} \boldsymbol {\alpha} _ {1} = \mathbf {0}. \tag {21} +$$ + +The unknown vector $\alpha_{1}$ can be determined as the kernel of $\mathsf{G}_1$ up to scale. Since $\mathsf{G}_1$ is of size $3\times 4$ , the kernel can be symbolically computed as a 4-dim vector: + +$$ +\boldsymbol {\alpha} _ {1} \propto \operatorname {K e r} \left(\mathrm {G} _ {1}\right) = \mathrm {Q} _ {1} \boldsymbol {\beta} _ {1}, \tag {22} +$$ + +where $\mathbb{Q}_1$ is a $4\times 5$ matrix and $\beta_{1} = [k^{4},k^{3},k^{2},k,1]^{\top}$ . We can replace $\alpha_{1}$ with $\mathbb{Q}_1\beta_1$ , then Eq. (19) can be rewritten as + +$$ +\mathbf {f} = \mathrm {V} _ {1} \boldsymbol {\alpha} _ {1} = \mathrm {V} _ {1} \mathrm {Q} _ {1} \boldsymbol {\beta} _ {1}. \tag {23} +$$ + +Plugging Eq. (23) into Eq. (4), we finally obtain a 16th-degree polynomial equation in $k$ : + +$$ +h (\mathbb {F} (k)) = c _ {1 6} k ^ {1 6} + \dots + c _ {1} k + c _ {0} = 0. \tag {24} +$$ + +We can recover $\mathbf{f}$ by substituting the real roots of Eq. (24) into Eq. (23). This algorithm provides at most 16 real solutions. + +# 3.4. 5-pt algorithm for $\mathbf{F} + \mathbf{f} + \mathbf{k}$ with single epipole + +Given only a single epipole $\mathbf{e}$ , we need two additional point pairs to solve the $F + f + k$ problem. We omit the details of the derivation and describe the differences only because the procedure of this algorithm is basically similar to Sec. 3.3. + +The null space of $\left[ \begin{array}{ccc}\mathbf{e}^{\mathsf{T}} & & \\ & \mathbf{e}^{\mathsf{T}} & \\ & & \mathbf{e}^{\mathsf{T}} \end{array} \right]$ can be symbolically given by + +$$ +V _ {2} = +$$ + +$$ +\left[ \begin{array}{c c c c c c} - \hat {y} & 1 + k z & 0 & 0 & 0 & 0 \\ \hat {x} & 0 & 0 & 0 & 0 & 0 \\ 0 & - \hat {x} & 0 & 0 & 0 & 0 \\ 0 & 0 & - \hat {y} & 1 + k z & 0 & 0 \\ 0 & 0 & \hat {x} & 0 & 0 & 0 \\ 0 & 0 & 0 & - \hat {x} & 0 & 0 \\ 0 & 0 & 0 & 0 & - \hat {y} & 1 + k z \\ 0 & 0 & 0 & 0 & \hat {x} & 0 \\ 0 & 0 & 0 & 0 & 0 & - \hat {x} \end{array} \right]. \tag {25} +$$ + +Since $\mathbf{V}_2$ is of size $9 \times 6$ , the unknown vector $\alpha_2$ for this problem becomes a 6-dim vector. Using the five point correspondences, $\mathsf{G}_2$ is represented as a $5 \times 6$ matrix, as shown in Eq. (20). Then, we can symbolically obtain the kernel of $\mathsf{G}_2$ , which is given as the matrix-vector product of a $6 \times 6$ matrix $\mathbb{Q}_2$ and $\beta_2 = [k^5, k^4, k^3, k^2, k, 1]^{\mathrm{T}}$ . Now we can express the fundamental matrix by + +$$ +\mathbf {f} = \mathrm {V} _ {2} \mathrm {Q} _ {2} \beta_ {2}. \tag {26} +$$ + +Substituting Eq. (26) into Eq. (4), we finally obtain a 21st-order polynomial equation in $k$ , i.e. + +$$ +h (\mathbb {F} (k)) = c _ {2 1} k ^ {2 1} + \dots + c _ {1} k + c _ {0} = 0. \tag {27} +$$ + +Thus, we can obtain at most 21 real solutions. + +# 3.5. Non-linear refinement + +After running a RANSAC scheme, we generally obtain many inlier points and perform a non-linear refinement to polish the accuracy of the parameters. For example, minimizing the symmetric epipolar distance is one of the major cost functions in the literature [11], i.e. + +$$ +L _ {\text {s y m}} = \sum_ {i = 1} ^ {n} \frac {\left(\mathbf {m} _ {i} ^ {\prime} {} ^ {\top} \mathbf {F} \mathbf {m} _ {i}\right) ^ {2}}{\left[ \mathbf {F} \mathbf {m} _ {i} \right] _ {1} ^ {2} + \left[ \mathbf {F} \mathbf {m} _ {i} \right] _ {2} ^ {2}} + \frac {\left(\mathbf {m} _ {i} ^ {\prime} {} ^ {\top} \mathbf {F} \mathbf {m} _ {i}\right) ^ {2}}{\left[ \mathbf {F} ^ {\top} \mathbf {m} _ {i} ^ {\prime} \right] _ {1} ^ {2} + \left[ \mathbf {F} ^ {\top} \mathbf {m} _ {i} ^ {\prime} \right] _ {2} ^ {2}}, \tag {28} +$$ + +where $[\mathbf{F}\mathbf{m}_i]_j^2$ denotes the square of the j-th element of the vector $\mathbf{F}\mathbf{m}_i$ . + +Since we have an initial guess of the focal length of the two images as $f_{1} = f_{2} = f$ , we can parameterize the fundamental matrix by $\mathbf{F} = \mathrm{diag}(1,1,f_2)\mathbf{E}\mathrm{diag}(1,1,f_1)$ + +where $\mathbf{E}$ represents an essential matrix. Thus, we can use the Helmke's method [12] to update $\mathbf{E}$ with preserving 5 DoFs. Also, we initialize the lens distortion of the two images by $k_{1} = k_{2} = k$ . + +However, those typical approaches of the non-linear refinement do not assume that epipoles are known, which in turn may degrade the fundamental matrix obtained by the proposed method. To avoid this issue, we introduce a regularization term of Eq. (2) as follows: + +$$ +L _ {\mathrm {e p i}} = \left\| \mathbf {F} \mathbf {e} \right\| ^ {2} + \left\| \mathbf {F} ^ {\mathsf {T}} \mathbf {e} ^ {\prime} \right\| ^ {2}. \tag {29} +$$ + +Note that the epipoles, $\mathbf{e}$ and $\mathbf{e}^{\prime}$ , are undistorted using Eq. (15) with $k_{1}$ and $k_{2}$ . In the case of the single epipole, the second term $\left\| \mathbf{F}^{\mathsf{T}}\mathbf{e}^{\prime}\right\|^{2}$ is simply dropped. + +The total cost function of the proposed scheme is given by jointly optimizing $L_{\mathrm{sym}}$ and $L_{\mathrm{epi}}$ with a weight $w$ : + +$$ +L = L _ {\text {s y m}} + w L _ {\text {e p i}}. \tag {30} +$$ + +# 4. Degenerate configurations + +Analysis of the degenerate configurations is important to avoid ambiguous 3D shape reconstructions and use the proposed method in real applications. Due to limitations of space, we give several simple examples for $\mathbf{F} + f$ problem with two known epipoles in this section. + +Degenerate configurations of two-view geometry in general cases have been extensively studied for the past decades [5, 17, 33, 35]. One typical situation that could often occur in practice is forward motion, where both focal length and radial distortion cannot be uniquely determined regardless of the point distributions. Forward motion alone is not the case for the proposed solvers, but forward motion with special point distributions is. One configuration where the proposed 2-point solver for $\mathbf{F} + f$ problem cannot be solved is that two epipoles and two point correspondences are collinear under forward motion. For example, the row rank of $\mathbb{M}_1$ is less than seven in Eq. (9) when $\mathbf{e} = \mathbf{e}' = [0,0,1]^{\mathrm{T}}$ , $\mathbf{m}_i = [u_i,0,1]^{\mathrm{T}}$ , $\mathbf{m}_i' = [-u_i,0,1]^{\mathrm{T}}$ , $i \in \{1,2\}$ . Another well-known degenerate configuration for the general solvers is that all 3D points are on a plane. However, in our case, unique solutions can be obtained in planar scenes when two epipoles are known [30]. + +The rigorous conditions can be given by analyzing the rank of submatrices of $\mathbb{N}_1$ and $\mathbb{M}_1$ ( $\mathbb{N}_2$ and $\mathbb{M}_2$ for the other problems as well). In other words, we first find epipoles and image points that cause rank deficiency, then link them to actual camera motions and 3D point distributions. However, as reported in the previous studies, it is not easy to reveal all possible ambiguities. We would leave the in-depth discussion to future research. + +# 5. Experiments + +This section reports experimental results on synthetic and real data. We conducted all experiments on a PC with Core i7-13700k. + +# 5.1. Implementation + +We have implemented five conventional methods and the four proposed methods in MATLAB, as shown in Tab. 1. We chose three Gröbner basis solvers that are the state-of-the-art based on the efficient parameterization (Eq. (4)): Larsson's 6-point solver for $\mathrm{F} + f$ problem (L6f) [21], Larsson's 7-point solver for $\mathrm{F} + f + k$ problem (L7fk) [21], and Martyushev's 7-point solver for $\mathrm{F} + f + k$ problem (M7fk) [24]. Those are designed for general scenes, therefore, epipoles are not assumed to be available. Moreover, we used two DLT-based approaches by Ito et al. [14]: the 3-point solver with two epipoles (I3), and the 5-point solver with a single epipole (I5). Although I3 and I5 do not guarantee to satisfy Eq. (3) or Eq. (4), we calculated focal length by simply applying Eq. (5) to a fundamental matrix given by I3 or I5. We used the root function for solving the polynomials of the proposed solvers, i.e. Eqs. (12), (24) and (27). + +# 5.2. Evaluation metrics + +We measured the following metrics to quantitatively evaluate the estimation accuracy: + +$\epsilon_{\mathrm{F}}$ Symmetric epipolar distance in pixels by applying $\mathbf{F}_{\mathrm{est}}$ onto the ground-truth 2D points. +$\epsilon_{f}$ Relative error by $|f_{\mathrm{est}} - f_{\mathrm{gt}}| / f_{\mathrm{gt}} \times 100[\%]$ . +$\epsilon_{k}$ Normalized pixel distance $[\%]$ between undistorted coordinates using $k_{\mathrm{est}}$ and $k_{\mathrm{gt}}$ . 100 points were uniformly sampled, and the mean distance is normalized by the diagonal length of the image. +$\epsilon_{\mathrm{R}}$ Angle-axis error by $\cos^{-1}\left(\frac{\operatorname{tr}(\mathbb{R}_{\mathrm{gt}}^{\mathrm{T}}\mathbb{R}_{\mathrm{est}}) - 1}{2}\right)$ [degrees]. +$\epsilon_{t}$ Cosine similarity by $\cos^{-1}\left(\frac{\mathbf{t}_{\mathrm{gt}}^{\mathrm{T}}\mathbf{t}_{\mathrm{est}}}{\|\mathbf{t}_{\mathrm{gt}}\| \|\mathbf{t}_{\mathrm{est}}\|}\right)$ [degrees]. + +# 5.3. Synthetic data + +We investigate the performance of the minimal solvers using synthetic data in this section. + +# 5.3.1 Scene configuration + +We created synthetic scenes as follows. Two cameras were randomly located in the area of $5.0\mathrm{m}\times 5.0\mathrm{m}$ and $2.0\mathrm{m}$ high to project each other, as shown in Fig. 1b. Small perturbations within 5 degrees and $\pm 0.2\mathrm{m}$ were added to the rotation and position of the cameras, respectively. The image resolution was $640\times 480$ , the focal length was set to + +
MethodReferenceProblemDecomposability Eqs. (3) and (4)# of points# of epipoles# of solutionsApproach
L6f[21]F+f✓6015
L7fk[21]F+f+k✓7068Gröbner basis
M7fk[24]F+f+k✓7068
I5[14]F511DLT
I3[14]F321
P4fF+f✓415
P2fF+f✓225Closed-form
P5fkF+f+k✓5116
P3fkF+f+k✓3221
+ +Table 1. Methods compared in the experiments. + +![](images/9fb1f99234204473fd039bf3db6b315f9e155a40cf1bc2de96ddd8f77bc55523.jpg) +Figure 3. The cumulative histogram of numerical accuracy for $10^{6}$ trials of randomly generated data without noise. + +![](images/7b9d7b60b7cd00909793ab8489f37ca8baf342f81e985ef7e73f1f5c20a6f788.jpg) + +![](images/7b19aa2cc71430f02437ba66449302d9c80a36623cf6ac7d1d9c9aa4722a2418.jpg) + +$f = 381.3$ , which is approximately $80^{\circ}$ HFOV. The radial lens distortion was set to $k = -0.2 / f^{2}$ for the $\mathsf{F} + f + k$ problem. We uniformly generated 100 3D points in the common viewing frustum of the two cameras and projected the 3D points onto the image plane. Then, we randomly picked the minimal number of the points needed for each method. + +# 5.3.2 Numerical stability + +In the first test, we investigated the numerical stability of the methods in noise free data. Figure 3 summarizes a cumulative histogram of $\epsilon_{\mathrm{F}}, \epsilon_{f}$ , and $\epsilon_{k}$ over $10^{6}$ independent trials. The figure indicates that the proposed methods are numerically stable. Comparing the methods in each categories, we see that P2f and P4f are better than I3, I5, and L6f in the $\mathbf{F} + f$ problem, and P5fk and P3fk are better than L7fk and M7fk in the $\mathbf{F} + f + k$ problem. Here, it should be noted that L7fk is so unstable as to be impractical. We further investigate this issue in the following experiments. + +# 5.3.3 Robustness w.r.t. noise on points + +To evaluate the robustness against the image noise, we measured the estimation errors by adding the zero-mean Gaussian noise onto point correspondences with the standard deviation $0 \leq \sigma \leq 2$ pixels. In this experiment, the image + +noise was not added to the epipoles, that is, the ground-truth values are given for the epipoles. Figure 4 shows the mean error over $10^{5}$ independent trials for each noise level. From the figure, we see that the proposed methods are the most robust against noise. Since the two DLT methods, I3 and I5, do not consider the decomposability conditions described in Eqs. (3) and (4), their focal length estimation are sensitive to image noise, which is even worse than the general methods, L6f and M7fk. The proposed methods outperform M7fk in estimation of the fundamental matrix and lens distortion while showing comparable accuracy in the focal length estimation. + +# 5.3.4 Robustness w.r.t. noise on epipoles + +In this experiment, we studied the noise robustness of the six methods using epipoles: two Ito et al.'s and four proposed methods. We added the Gaussian noise on epipoles varying $0 \leq \sigma \leq 2$ while fixing the image noise as $\sigma = 0.5$ . Figure 5 reports the mean error over $10^{5}$ independent trials for each noise level. The results have similar trends to the previous experiments. Among the proposed methods, P4f and P5fk are more robust to image noise than P2f and P4fk because P4f and P5fk utilizes a single epipole. + +![](images/99d89e7e4e9c19cc85c907b3c7ce54016915323b0cd28dfc4f8751582260d8cb.jpg) +Figure 4. Mean error w.r.t. the image noise on point correspondences over $10^{5}$ trials for each noise level. + +![](images/8994edff9cdb188bdb4eead015c6c09392db192299040990fea3b24d80fb3968.jpg) + +![](images/5664e932849efbcaf2d8da12b48902f98a13f6b517becc20edfe424d1dd1a4cd.jpg) + +![](images/e134de50c0baa8f25103f622cd72d2c8c5c4238a3ce5843b6563dff8b1c47985.jpg) +Figure 5. Mean error w.r.t. the image noise on epipoles over $10^{5}$ trials for each noise level. + +![](images/c8c3686f14bef2207ce398bbb387a47f3fd74aa8ad9fec61e00fdbdd1527d04e.jpg) + +![](images/9c6e1916cbd1677671060efe4a8d3bd5571cf855bf3175d5e89b6e2380cbc5ce.jpg) + +![](images/37b9b09e447e426ed17aecde9705a56f68734e27eacc23d5270077a0ef260501.jpg) +Figure 6. Runtime comparison of the minimal solvers. + +# 5.3.5 Computational time + +Figure 6 shows the mean runtime of all methods over $10^{6}$ independent trials. The computational time of the proposed methods is less than 1 msec, which is not as fast as the Ito et al.'s methods, but is still reasonably fast enough for real-time applications. + +# 5.4. Real data + +In this experiments, we incorporated each method into RANSAC together with the non-linear refinement to investigate the performance in real data. We excluded L7fk due to its instability and high computational cost shown in the synthetic data experiments in Sec. 5.3. + +# 5.4.1 Dataset + +We used two publicly available dataset where multiple cameras are mutually projected: + +HumanEva [32] Four RGB cameras with the $656 \times 490$ resolution are installed in the corners of a room. The intrinsic parameters are calibrated by Zhang's method, then the extrinsics are calculated using Vicon sensors. A single person is asked to do simple actions such as walking, jogging, etc. There are two combinations of mutual camera projections with two epipoles. + +Panoptic studio $[16]^{2}$ 30 HD cameras, 480 VGA cameras, and 5 Kinect2 are installed on the walls of a domeshaped studio. Both the intrinsic and extrinsic parameters of all cameras are simultaneously calibrated based on the structure-from-motion. All sensors are used for recording multi-person interactions. There are 20 combinations of a single epipole and 80 combinations of two epipoles in the HD cameras. + +We chose a video sequence from each dataset in which a single person moves around the scene: S2 sequence of HumanEva (Fig. 2a) and dance1 of Panoptic studio (Fig. 2b). Then, 2D human joints on the video frames were detected using OpenPose [7]. The neck and hip joints were selected as the point correspondences because they are less likely to be occluded and are easily observed from any camera. We manually labeled epipole locations in each image. + +
MethodεRεtεfεkiter.time
L6f28.014.348.80.7812410.25
M7fk29.815.156.11.4628197.69
I332.816.170.00.26920.04
P2f22.711.348.00.26390.03
P3fk24.712.346.91.111460.04
+ +(a) HumanEva: S2 (2 epipoles, 2 sequences) + +
MethodεRεtεfεkiter.time
L6f17.38.518.62.70100002.68
M7fk23.812.219.82.611000033.43
I515.512.430.72.69100000.83
P4f11.36.818.02.68100001.22
P5fk11.26.518.22.09100003.64
+ +(b) Panoptic studio: dance1 (single epipole, 20 sequences) + +
MethodεRεtεfεkiter.time
L6f10.34.919.82.67100001.80
M7fk12.05.920.02.851000024.88
I313.18.033.72.6620010.15
P2f6.12.817.72.663180.04
P3fk6.63.217.91.7224380.40
+ +(c) Panoptic studio: dance1 (2 epipoles, 80 sequences) + +Table 2. Quantitative results of real image dataset (best in bold and second-best underlined). iter.: the number of RANSAC iterations, time: the total processing time of RANSAC and the non-linear refinement in seconds. + +# 5.4.2 Quantitative results + +For testing the methods, we configured RANSAC to have the threshold by 3 pixels, the confidence by 0.995, and the maximum iteration number by 10000. The random seed was fixed for all methods during a single trial so that the same sample points were drawn. After RANSAC, the nonlinear refinement described in Sec. 3.5 was performed on inliers to polish the camera parameters to be more accurate. The two general solvers, L6f and M7fk, optimized only the symmetric epipolar distance $L_{\mathrm{sym}}$ in Eq. (29). The rest of the solvers utilizing epipoles employed the total cost function $L$ in Eq. (30) with a weight $w = 100 \times n$ to balance $L_{\mathrm{sym}}$ and $L_{\mathrm{epi}}$ depending on the number of the points $n$ . + +We conducted 100 and 10 trials for each camera pair of S2 and dance1, respectively. Table 2 reports the average values of $(\epsilon_{\mathrm{R}}, \epsilon_{\mathrm{t}}, \epsilon_{f}, \epsilon_{k})$ , the number of RANSAC iterations, and the total processing time. Comparing Tab. 2a with Tabs. 2b and 2c, we can see that all methods show better scores in dance1 even though two epipoles are available in HumanEva. The person in dance1 is captured in the higher-resolution image than in HumanEva, resulting in higher localization accuracy of the 2D joints. + +![](images/eab72c54270ee1c7cf3c1042e6202a103a6cb67b5e6628fe70e5afa33198b371.jpg) +(a) 2D trajectory of the neck. + +![](images/34e72345ef89d82a5ba98e1bbaee4f543903960e2164db9af423de8e0e9906c4.jpg) +(c) Top view. + +![](images/de3e95baf29bedc7e13f0be7e36770923b4097aa2e1db6338a8e270fda81706f.jpg) +(b) Reprojection of estimated epipoles (green area in (a)). + +![](images/4f623994e9868250f22ba0fcd19dc84ad86aeb283cbbcb9834260287631dd827.jpg) +(d) Side view. +Figure 7. 3D shape reconstruction of HumanEva S2. + +![](images/cbd587f7e36a92494e271d6f4e5be12527e304a2c8a11ff860416dad8155677e.jpg) +(a) 2D trajectory of the neck. + +![](images/0d01220f421f53ae428a3f1e3ec2583b4d14c84f3580a7cb11ea2f11892e9d2e.jpg) +(b) Reprojection of estimated epipoles. (green area in (a)) + +![](images/d99c605f1a38e79a23dc15a6752f6e44a8bc6d88f22e50b048e8b15ed42f5a52.jpg) +(c) Top view. +Figure 8. 3D shape reconstruction of Panoptic studio dance1. + +![](images/7462b572e50d9be3959d830517ad7df6bb8798d9e85f74624f2eecac46143d36.jpg) +(d) Side view. + +Table 2 indicates that the proposed solvers outperform the conventional methods in either case of one or two epipoles. The proposed solvers show the best or the second-best scores in most evaluation criteria. For example, P2f and P4f are more than 100 times faster than M7fk while achieving lower estimation errors. Although P2f and P4f does not estimate the radial distortion $k$ in RANSAC, the non-linear refinement successfully converges to an accurate solution of $k$ due to a good initial guess of $\mathbf{F}$ and $\mathbf{f}$ . On the other hand, in spite of the use of epipoles, I3 and I5 are inferior to the general solvers L6f and M7fk. As reported in Sec. 5.3, two Ito's methods are sensitive to image noise. According to the above observations, we can conclude that satisfying the decomposability conditions, Eqs. (3) and (4), significantly improves the estimation accuracy even with known epipoles. + +# 5.4.3 Qualitative results + +Figures 7 and 8 visualize a 3D shape reconstruction of S2 and dance1, respectively. For ease of viewing, only neck joints are shown in both 2D and 3D images. We plotted the position of estimated epipoles over 30 independent trials in Figs. 7b and 8b. The P3fk's epipole and the ground-truth overlap so closely that the difference is not visible. On the other hand, the camera motion given by M7fk has large errors and the epipole is estimated on a different place in each trial. This is consistent with the result in Tab. 2 where the proposed methods have the smallest motion errors. Also, we can visually validate that P3fk reconstructs a 3D shape more accurately than M7fk in Figs. 7c, 7d, 8c and 8d. + +# 6. Limitations and future work + +One of the limitations is that epipole positions are manually annotated. This is not a critical issue in data set creation (Figs. 2a and 2b) because device installations and data capturing spend time dominantly. However, a fast-automatic epipole detector is required to use the proposed method in real-time applications such as multi-agent Visual-SLAM [28, 29, 36] shown in Figs. 2c and 2d. Although direct epipole estimation has been studied for several decades [2, 8, 22], unfortunately it cannot be said as active nor extensive. We think that the manual labeling is merely a current limitation, which can be resolved by future effort in the computer vision community. For instance, a quick workaround is to place a camera at the center of a colored sphere or circle and detect the camera's center in images by ellipse fitting. Alternatively, there are more sophisticated ways that use wifi/radio waves or IMUs to find the relative locations between devices in 3D space [3]. + +Another future work is to extend the proposed approach to multi-view geometry, just as Sato [30] extended Ito et al.'s DLT method [14] for obtaining a trifocal or quadrifocal tensor. Combining the multi-view extension with an automatic epipole detector, we can expect that the proposed approach stabilizes multi-agent Visual-SLAM with wide baselines for large-scale scene. + +# 7. Conclusion + +We have presented four minimal solutions to the uncalibrated two-view geometry where one or two epipoles are visible in the image plane. All solvers are manually formulated as higher-order polynomials in a single variable without an automatic Gröbner basis generator. We briefly discussed the degenerate conditions and showed several examples where the proposed solvers are feasible but not the conventional methods. In the experiments, we first compared the proposed solvers with the conventional methods in the numerical stability and robustness against image noise using synthetic data. Then, we demonstrated that the proposed + +solvers successfully stabilize the structure-from-motion using human joints as point correspondences, which are noisy and less accurate than image feature points. Through these experiments, the proposed solvers outperform the conventional methods in estimation accuracy with maintaining computational efficiency. Finally, we discussed the current limitations of the proposed approach and future work to be applicable in real-time applications. We hope this paper will motivate the computer vision community to develop automatic epipole detectors more extensively. + +# References + +[1] Sameer Agarwal, Yasutaka Furukawa, Noah Snavely, Ian Simon, Brian Curless, Steven M Seitz, and Richard Szeliski. Building rome in a day. Communications of the ACM, 54(10):105-112, 2011. 1 +[2] Farhoosh Alghabi and Mohsen Soryani. Direct computation of epipoles using two pairs of point-line correspondences. In 2008 Second International Symposium on Intelligent Information Technology Application, volume 3, pages 486-489, 2008. 9 +[3] Safar M Asaad and Halgurd S Maghdid. A comprehensive review of indoor/outdoor localization solutions in IoT era: Research challenges and future perspectives. Computer Networks, page 109041, 2022. 9 +[4] Shai Avidan and Amnon Shashua. Novel view synthesis in tensor space. In Proceedings of IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 1034-1040. IEEE, 1997. 1 +[5] GN Newsam DQ Huynh MJ Brooks and HP Pan. Recovering unknown focal lengths in self-calibration: An essentially linear algorithm and degenerate configurations. In Proc. ISPRS-Congress, volume 31, pages 575-580. Citeseer, 1996. 5 +[6] Cesar Cadena, Luca Carlone, Henry Carrillo, Yasir Latif, Davide Scaramuzza, José Neira, Ian Reid, and John J Leonard. Past, present, and future of simultaneous localization and mapping: Toward the robust-perception age. IEEE Transactions on robotics, 32(6):1309-1332, 2016. 1 +[7] Z. Cao, G. Hidalgo Martinez, T. Simon, S. Wei, and Y. A. Sheikh. Openpose: Realtime multi-person 2d pose estimation using part affinity fields. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2019. 7 +[8] Huiqin Chen, Emanuel Aldea, and Sylvie Le Hégarat-Mascle. Determining epipole location integrity by multimodal sampling. In 2019 16th IEEE International Conference on Advanced Video and Signal Based Surveillance (AVSS), pages 1-8. IEEE, 2019. 9 +[9] Martin A Fischler and Robert C Bolles. Random sample consensus: a paradigm for model fitting with applications to image analysis and automated cartography. Communications of the ACM, 24(6):381-395, 1981. 1 +[10] Andrew W Fitzgibbon. Simultaneous linear estimation of multiple view geometry and lens distortion. In Proceedings of the 2001 IEEE Computer Society Conference on Computer Vision and Pattern Recognition. CVPR 2001, volume 1, pages I-I. IEEE, 2001. 2 + +[11] Richard I. Hartley and Andrew Zisserman. Multiple View Geometry in Computer Vision. Cambridge University Press, ISBN: 0521540518, second edition, 2004. 1, 2, 4 +[12] Uwe Helmke, Knut Hüper, Pei Yean Lee, and John Moore. Essential matrix estimation using gauss-newton iterations on a manifold. International Journal of Computer Vision, 74(2):117-136, 2007. 5 +[13] Berthold KP Horn. Recovering baseline and orientation from essential matrix. J. Opt. Soc. Am, 110, 1990. 2 +[14] M. Ito, T. Sugimura, and J. Sato. Recovering structures and motions from mutual projection of cameras. In 2002 International Conference on Pattern Recognition, volume 3, pages 676-679 vol.3, 2002. 1, 5, 6, 9 +[15] Fangyuan Jiang, Yubin Kuang, Jan Erik Solem, and Kalle Åström. A minimal solution to relative pose with unknown focal length and radial distortion. In Asian Conference on Computer Vision, pages 443-456. Springer, 2014. 1 +[16] Hanbyul Joo, Hao Liu, Lei Tan, Lin Gui, Bart Nabbe, Iain Matthews, Takeo Kanade, Shohei Nobuhara, and Yaser Sheikh. Panoptic studio: A massively multiview system for social motion capture. In Proceedings of the IEEE International Conference on Computer Vision, pages 3334-3342, 2015. 2, 7 +[17] Kenichi Kanatani and Chikara Matsunaga. Closed-form expression for focal lengths from the fundamental matrix. In Proc. 4th Asian Conf. Comput. Vision, volume 1, pages 128-133. CiteSeer, 2000. 5 +[18] Yubin Kuang, Jan E Solem, Fredrik Kahl, and Kalle Astrom. Minimal solvers for relative pose with a single unknown radial distortion. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 33-40, 2014. 1 +[19] Zuzana Kukelova, Martin Bujnak, and Tomas Pajdla. Polynomial eigenvalue solutions to the 5-pt and 6-pt relative pose problems. In Proceedings of the British Machine Vision Conference, pages 56.1-56.10. BMVA Press, 2008. doi:10.5244/C.22.56.1 +[20] Zuzana Kukelova, Joe Kileel, Bernd Sturmfels, and Tomas Pajdla. A clever elimination strategy for efficient minimal solvers. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4912-4921, 2017. 2 +[21] Viktor Larsson, Kalle Astrom, and Magnus Oskarsson. Efficient solvers for minimal problems by syzygy-based reduction. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 820-829, 2017. 1, 5, 6 +[22] Jonathan Lawn and Roberto Cipolla. Epipole estimation using affine motion parallax. In Proceedings of the British Machine Vision Conference, pages 38.1-38.10. BMVA Press, 1993. doi:10.5244/C.7.38.9 +[23] Hongdong Li. A simple solution to the six-point two-view focal-length problem. In European Conference on Computer Vision, pages 200-213. Springer, 2006. 1 +[24] Evgeniy Martyushev, Jana Vrablikova, and Tomas Pajdla. Optimizing elimination templates by greedy parameter search. In Proceedings of the IEEE/CVF Conference + +on Computer Vision and Pattern Recognition, pages 15754-15764, 2022. 5, 6 +[25] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. In European conference on computer vision, pages 405-421. Springer, 2020. 1 +[26] Raul Mur-Artal, Jose Maria Martinez Montiel, and Juan D Tardos. Orb-slam: a versatile and accurate monocular slam system. IEEE transactions on robotics, 31(5):1147-1163, 2015. 1 +[27] David Nister and Frederik Schaffalitzky. Four points in two or three calibrated views: Theory and practice. International Journal of Computer Vision, 67:211-231, 2006. 1 +[28] Jacob M Perron, Rui Huang, Jack Thomas, Lingkang Zhang, Ping Tan, and Richard T Vaughan. Orbiting a moving target with multi-robot collaborative visual slam. In Proceedings of the Workshop on Multi-View Geometry in Robotics (MVI-GRO), Rome, Italy, pages 1339–1344, 2015. 2, 9 +[29] Thomas Pollok and Eduardo Monari. A visual slam-based approach for calibration of distributed camera networks. In 2016 13th IEEE International Conference on Advanced Video and Signal Based Surveillance (AVSS), pages 429-437, 2016. 2, 9 +[30] Jun Sato. Recovering multiple view geometry from mutual projections of multiple cameras. International Journal of Computer Vision, 66(2):123-140, 2006. 1, 5, 9 +[31] Johannes Lutz Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In Conference on Computer Vision and Pattern Recognition (CVPR), 2016. 1 +[32] Leonid Sigal, Alexandru O Balan, and Michael J Black. Humaneva: Synchronized video and motion capture dataset and baseline algorithm for evaluation of articulated human motion. International journal of computer vision, 87(1):4-27, 2010. 2, 7 +[33] Carsten Steger. Estimating the fundamental matrix under pure translation and radial distortion. ISPRS Journal of Photogrammetry and Remote Sensing, 74:202-217, 2012. 5 +[34] Henrik Stewénius, David Nister, Fredrik Kahl, and Frederik Schaffalitzky. A minimal solution for relative pose with unknown focal length. Image and Vision Computing, 26(7):871-877, 2008. 1 +[35] Changchang Wu. Critical configurations for radial distortion self-calibration. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 25-32, 2014. 5 +[36] Danping Zou and Ping Tan. Coslam: Collaborative visual slam in dynamic environments. IEEE Transactions on Pattern Analysis and Machine Intelligence, 35(2):354-366, 2013. 2, 9 \ No newline at end of file diff --git a/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/images.zip b/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..ed10aea659a4d522975c4b54f17ed460a87cccb7 --- /dev/null +++ b/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:0c2016c911a696158a1a63a27c79acedbe9e8dff7a158ea1300fd81e6d87beae +size 624941 diff --git a/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/layout.json b/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..604498d42d6b37cc0bff04817780ee6b79ae3ac3 --- /dev/null +++ b/2023/Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles/layout.json @@ -0,0 +1,12706 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 58, + 103, + 536, + 122 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 103, + 536, + 122 + ], + "spans": [ + { + "bbox": [ + 58, + 103, + 536, + 122 + ], + "type": "text", + "content": "Minimal Solutions to Uncalibrated Two-view Geometry with Known Epipoles" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 261, + 144, + 332, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 261, + 144, + 332, + 156 + ], + "spans": [ + { + "bbox": [ + 261, + 144, + 332, + 156 + ], + "type": "text", + "content": "Gaku Nakano" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 253, + 158, + 341, + 171 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 253, + 158, + 341, + 171 + ], + "spans": [ + { + "bbox": [ + 253, + 158, + 341, + 171 + ], + "type": "text", + "content": "NEC Corporation" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 206, + 171, + 389, + 186 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 206, + 171, + 389, + 186 + ], + "spans": [ + { + "bbox": [ + 206, + 171, + 389, + 186 + ], + "type": "text", + "content": "1753 Shimonumabe, Kawasaki, Japan" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 252, + 188, + 342, + 198 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 252, + 188, + 342, + 198 + ], + "spans": [ + { + "bbox": [ + 252, + 188, + 342, + 198 + ], + "type": "text", + "content": "g-nakano@nec.com" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 143, + 227, + 192, + 239 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 227, + 192, + 239 + ], + "spans": [ + { + "bbox": [ + 143, + 227, + 192, + 239 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 251, + 289, + 432 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 251, + 289, + 432 + ], + "spans": [ + { + "bbox": [ + 46, + 251, + 289, + 432 + ], + "type": "text", + "content": "This paper proposes minimal solutions to uncalibrated two-view geometry with known epipoles. Exploiting the epipoles, we can reduce the number of point correspondences needed to find the fundamental matrix together with the intrinsic parameters: the focal length and the radial lens distortion. We define four cases by the number of available epipoles and unknown intrinsic parameters, then derive a closed-form solution for each case formulated as a higher-order polynomial in a single variable. The proposed solvers are more numerically stable and faster by orders of magnitude than the conventional 6- or 7-point algorithms. Moreover, we demonstrate by experiments on the human pose dataset that the proposed method can solve two-view geometry even with 2D human pose, of which point localization is noisier than general feature point detectors." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 454, + 128, + 467 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 454, + 128, + 467 + ], + "spans": [ + { + "bbox": [ + 47, + 454, + 128, + 467 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 474, + 287, + 594 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 474, + 287, + 594 + ], + "spans": [ + { + "bbox": [ + 46, + 474, + 287, + 594 + ], + "type": "text", + "content": "Solving the two-view geometry of uncalibrated cameras is one of the basic tasks for many computer vision applications such as the structure-from-motion [1, 31], Visual-SLAM [6, 26], and novel view synthesis [4, 25]. The goal of this problem is to find the fundamental matrix and the intrinsic parameters of the two cameras from point correspondences. Since point correspondences are generally contaminated by outliers, many efforts have been devoted to develop efficient and numerically stable solvers that can be incorporated into RANSAC [9] to extract a set of inlier point pairs." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 594, + 288, + 714 + ], + "type": "text", + "content": "It is known that the fundamental matrix with an unknown focal length and known principal points can be determined by six point correspondences. Stewenius et al. [34] first developed a minimal solution to this problem by manually deriving Gröbner basis. Then, other methods were proposed based on various approaches, e.g. the hidden variable technique [23], the polynomial eigenvalue problem [19], the automatic generator [21]. Following the success of the 6-point algorithms, research interests have been expanded to deal with the radial lens distortion. Jiang et al. [15] and" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 228, + 547, + 324 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 228, + 547, + 324 + ], + "spans": [ + { + "bbox": [ + 304, + 228, + 547, + 324 + ], + "type": "text", + "content": "Kuang et al. [18] showed that the fundamental matrix with both unknown focal length and unknown radial distortion can be solved by seven point correspondences. However, with more intrinsic parameters to be estimated, new issues arise in terms of numerical stability and computational efficiency. The root cause is that those methods assume general conditions with no restrictions on the camera motion and thus cannot reduce the number of point correspondences." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 327, + 547, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 327, + 547, + 567 + ], + "spans": [ + { + "bbox": [ + 304, + 327, + 547, + 567 + ], + "type": "text", + "content": "To address the above issue, we assume that two cameras are mutually observed, as shown in Fig. 1. This is not a rare and limited situation but occurs in real applications. For example, multiple cameras are installed to capture human behaviors from " + }, + { + "bbox": [ + 304, + 327, + 547, + 567 + ], + "type": "inline_equation", + "content": "360^{\\circ}" + }, + { + "bbox": [ + 304, + 327, + 547, + 567 + ], + "type": "text", + "content": " views in dataset creation (Figs. 2a and 2b). In dynamic scenes such as multi-agent Visual-SLAM, robots collaboratively create a single map of a wide area (Fig. 2c). Visual-SLAM can also be applied to calibrate camera networks consisting of fixed and moving cameras (Fig. 2d). In those scenarios, epipoles or 2D positions of the camera center are directly obtainable from images. Epipoles constrain a fundamental matrix to be rank-deficient, thus reducing the number of point correspondences. Nistér [27] showed a theory for finding a relative rotation of calibrated cameras with a single epipole. Ito et al. [14] utilized epipole(s) for fundamental matrix estimation, then Sato [30] generalized it to three- and four-view geometry. However, both methods are based on the DLT algorithm [11], thus not minimal solutions. They also do not address how to find the intrinsic parameters." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 570, + 548, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 548, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 548, + 714 + ], + "type": "text", + "content": "In this paper, we propose minimal solutions utilizing epipole(s) to determine a fundamental matrix with unknown intrinsic camera parameters: focal length and radial lens distortion. The proposed method has four variations depending on the number of available epipoles and the number of unknown parameters to be estimated. Moreover, we introduce a simple regularization term to fix the epipoles during the non-linear optimization, which is conducted on inliers after RANSAC. Through exhaustive experiments, we show that the proposed algorithms provide more reliable estimations than the conventional methods while achieving a significant acceleration by orders of magnitude." + } + ] + } + ], + "index": 14 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 493, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 493, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 493, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13361" + } + ] + } + ], + "index": 15 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 59, + 69, + 275, + 144 + ], + "blocks": [ + { + "bbox": [ + 59, + 69, + 275, + 144 + ], + "lines": [ + { + "bbox": [ + 59, + 69, + 275, + 144 + ], + "spans": [ + { + "bbox": [ + 59, + 69, + 275, + 144 + ], + "type": "image", + "image_path": "d1df319f1136e9f5f6e4398f5f5a1a38be9a6888e895be889fa1feda70d86891.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 59, + 171, + 275, + 247 + ], + "blocks": [ + { + "bbox": [ + 47, + 149, + 286, + 171 + ], + "lines": [ + { + "bbox": [ + 47, + 149, + 286, + 171 + ], + "spans": [ + { + "bbox": [ + 47, + 149, + 286, + 171 + ], + "type": "text", + "content": "(a) Single epipole case. The projection of the second camera is observed as " + }, + { + "bbox": [ + 47, + 149, + 286, + 171 + ], + "type": "inline_equation", + "content": "\\mathbf{e}" + }, + { + "bbox": [ + 47, + 149, + 286, + 171 + ], + "type": "text", + "content": " in the first camera." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 59, + 171, + 275, + 247 + ], + "lines": [ + { + "bbox": [ + 59, + 171, + 275, + 247 + ], + "spans": [ + { + "bbox": [ + 59, + 171, + 275, + 247 + ], + "type": "image", + "image_path": "e8a164bc1c660ac212b69445da864d9b3d7ce00f9a1c207bc94b5d25f882ebc9.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 251, + 286, + 273 + ], + "lines": [ + { + "bbox": [ + 47, + 251, + 286, + 273 + ], + "spans": [ + { + "bbox": [ + 47, + 251, + 286, + 273 + ], + "type": "text", + "content": "(b) Two epipoles case. The two cameras are mutually observed as e and " + }, + { + "bbox": [ + 47, + 251, + 286, + 273 + ], + "type": "inline_equation", + "content": "\\mathbf{e}^{\\prime}" + }, + { + "bbox": [ + 47, + 251, + 286, + 273 + ], + "type": "text", + "content": " in each image." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 48, + 298, + 145, + 372 + ], + "blocks": [ + { + "bbox": [ + 48, + 298, + 145, + 372 + ], + "lines": [ + { + "bbox": [ + 48, + 298, + 145, + 372 + ], + "spans": [ + { + "bbox": [ + 48, + 298, + 145, + 372 + ], + "type": "image", + "image_path": "cac7d0c5b923cf282edfbdebd8fc016dedb70a77078471817be11ab33ea4787f.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 153, + 297, + 280, + 371 + ], + "blocks": [ + { + "bbox": [ + 70, + 277, + 259, + 289 + ], + "lines": [ + { + "bbox": [ + 70, + 277, + 259, + 289 + ], + "spans": [ + { + "bbox": [ + 70, + 277, + 259, + 289 + ], + "type": "text", + "content": "Figure 1. Two-view geometry with known epipoles." + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 153, + 297, + 280, + 371 + ], + "lines": [ + { + "bbox": [ + 153, + 297, + 280, + 371 + ], + "spans": [ + { + "bbox": [ + 153, + 297, + 280, + 371 + ], + "type": "image", + "image_path": "b8d7c984d1775a217687fa17aede034ddedd54c5d2fc9df3febed38928dbe64e.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 48, + 387, + 144, + 460 + ], + "blocks": [ + { + "bbox": [ + 61, + 375, + 132, + 386 + ], + "lines": [ + { + "bbox": [ + 61, + 375, + 132, + 386 + ], + "spans": [ + { + "bbox": [ + 61, + 375, + 132, + 386 + ], + "type": "text", + "content": "(a) HumanEva [32]" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 48, + 387, + 144, + 460 + ], + "lines": [ + { + "bbox": [ + 48, + 387, + 144, + 460 + ], + "spans": [ + { + "bbox": [ + 48, + 387, + 144, + 460 + ], + "type": "image", + "image_path": "dd78af87cf180d31da669a0e2ef406f1fd51f4c99c0952605a6bc53d2308d298.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 464, + 287, + 486 + ], + "lines": [ + { + "bbox": [ + 47, + 464, + 287, + 486 + ], + "spans": [ + { + "bbox": [ + 47, + 464, + 287, + 486 + ], + "type": "text", + "content": "(c) Collaborative Visual- (d) SLAM-based calibration for surveilSLAM [28, 36] lance and moving cameras [29]" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 47, + 489, + 286, + 511 + ], + "lines": [ + { + "bbox": [ + 47, + 489, + 286, + 511 + ], + "spans": [ + { + "bbox": [ + 47, + 489, + 286, + 511 + ], + "type": "text", + "content": "Figure 2. Mutual camera projections in applications. (a)-(b): Human pose dataset. (c)-(d): Multi-agent Visual-SLAM." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 151, + 387, + 282, + 460 + ], + "blocks": [ + { + "bbox": [ + 159, + 375, + 272, + 386 + ], + "lines": [ + { + "bbox": [ + 159, + 375, + 272, + 386 + ], + "spans": [ + { + "bbox": [ + 159, + 375, + 272, + 386 + ], + "type": "text", + "content": "(b) Panoptic studio dataset [16]" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 151, + 387, + 282, + 460 + ], + "lines": [ + { + "bbox": [ + 151, + 387, + 282, + 460 + ], + "spans": [ + { + "bbox": [ + 151, + 387, + 282, + 460 + ], + "type": "image", + "image_path": "b4817c98b48328fb9c351e75f0aa0cd0f927873ee2ac00dae49a68999ff9a749.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "bbox": [ + 47, + 529, + 229, + 543 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 529, + 229, + 543 + ], + "spans": [ + { + "bbox": [ + 47, + 529, + 229, + 543 + ], + "type": "text", + "content": "2. Uncalibrated two-view geometry" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "spans": [ + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "type": "text", + "content": "This section describes the theoretical background of two-view geometry for uncalibrated cameras. We represent 2D points as their homogeneous coordinates, i.e. " + }, + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "type": "inline_equation", + "content": "\\mathbf{m} = [u,v,1]^{\\mathrm{T}}" + }, + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "type": "text", + "content": ", and assume a pinhole camera model whose intrinsic parameters are partially known: the principal point is approximated by the image center; the skewness is zero. Solving uncalibrated two-view geometry is to find the focal length " + }, + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "type": "text", + "content": " and the radial lens distortion " + }, + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "type": "text", + "content": " as well as the relative rotation " + }, + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "type": "inline_equation", + "content": "\\mathbb{R}" + }, + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "type": "text", + "content": " and translation " + }, + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "type": "inline_equation", + "content": "\\mathfrak{t}" + }, + { + "bbox": [ + 47, + 549, + 286, + 655 + ], + "type": "text", + "content": " between the two cameras." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 47, + 657, + 286, + 692 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 657, + 286, + 692 + ], + "spans": [ + { + "bbox": [ + 47, + 657, + 286, + 692 + ], + "type": "text", + "content": "Given " + }, + { + "bbox": [ + 47, + 657, + 286, + 692 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 47, + 657, + 286, + 692 + ], + "type": "text", + "content": " pairs of a 2D point correspondence " + }, + { + "bbox": [ + 47, + 657, + 286, + 692 + ], + "type": "inline_equation", + "content": "\\{\\mathbf{m}_i \\leftrightarrow \\mathbf{m}_i'\\}" + }, + { + "bbox": [ + 47, + 657, + 286, + 692 + ], + "type": "text", + "content": " between the two cameras, each point pair is constrained by a " + }, + { + "bbox": [ + 47, + 657, + 286, + 692 + ], + "type": "inline_equation", + "content": "3 \\times 3" + }, + { + "bbox": [ + 47, + 657, + 286, + 692 + ], + "type": "text", + "content": " fundamental matrix " + }, + { + "bbox": [ + 47, + 657, + 286, + 692 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 47, + 657, + 286, + 692 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 102, + 699, + 287, + 715 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 102, + 699, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 102, + 699, + 287, + 715 + ], + "type": "interline_equation", + "content": "\\mathbf {m} _ {i} ^ {\\prime} ^ {\\top} \\mathbf {F m} _ {i} = \\left(\\mathbf {m} _ {i} ^ {\\prime} \\otimes \\mathbf {m} _ {i}\\right) ^ {\\top} \\mathbf {f} = 0, \\tag {1}", + "image_path": "db70f54a253d1bcf0cef77caef3aff0bd5a5c34a9bceb150bcd5886c3ed6791e.jpg" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 72, + 545, + 95 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 545, + 95 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 306, + 72, + 545, + 95 + ], + "type": "inline_equation", + "content": "\\otimes" + }, + { + "bbox": [ + 306, + 72, + 545, + 95 + ], + "type": "text", + "content": " denotes the Kronecker product and " + }, + { + "bbox": [ + 306, + 72, + 545, + 95 + ], + "type": "inline_equation", + "content": "\\mathbf{f}" + }, + { + "bbox": [ + 306, + 72, + 545, + 95 + ], + "type": "text", + "content": " is a 9-dim vector representation of " + }, + { + "bbox": [ + 306, + 72, + 545, + 95 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 306, + 72, + 545, + 95 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 95, + 545, + 132 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 95, + 545, + 132 + ], + "spans": [ + { + "bbox": [ + 306, + 95, + 545, + 132 + ], + "type": "text", + "content": "Epipoles, " + }, + { + "bbox": [ + 306, + 95, + 545, + 132 + ], + "type": "inline_equation", + "content": "\\mathbf{e} = [x,y,1]^{\\top}" + }, + { + "bbox": [ + 306, + 95, + 545, + 132 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 95, + 545, + 132 + ], + "type": "inline_equation", + "content": "\\mathbf{e}' = [x',y',1]^{\\top}" + }, + { + "bbox": [ + 306, + 95, + 545, + 132 + ], + "type": "text", + "content": ", are the 2D projections of the image center of one camera onto the image plane of the other camera, which satisfy" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 391, + 140, + 545, + 152 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 391, + 140, + 545, + 152 + ], + "spans": [ + { + "bbox": [ + 391, + 140, + 545, + 152 + ], + "type": "interline_equation", + "content": "\\mathbf {F} \\mathbf {e} = \\mathbf {F} ^ {\\top} \\mathbf {e} ^ {\\prime} = \\mathbf {0}. \\tag {2}", + "image_path": "83f225104f2e8afbc354512af3dbf7dbe1f7ea1721bce01cad07a7ff47c9586c.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 162, + 544, + 185 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 162, + 544, + 185 + ], + "spans": [ + { + "bbox": [ + 306, + 162, + 544, + 185 + ], + "type": "text", + "content": "Equation (2) leads to one of the constraints on " + }, + { + "bbox": [ + 306, + 162, + 544, + 185 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 306, + 162, + 544, + 185 + ], + "type": "text", + "content": ", i.e. " + }, + { + "bbox": [ + 306, + 162, + 544, + 185 + ], + "type": "inline_equation", + "content": "\\operatorname*{det}(\\mathbf{F}) = 0" + }, + { + "bbox": [ + 306, + 162, + 544, + 185 + ], + "type": "text", + "content": ". Thus, " + }, + { + "bbox": [ + 306, + 162, + 544, + 185 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 306, + 162, + 544, + 185 + ], + "type": "text", + "content": " is of rank two." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 306, + 186, + 544, + 209 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 186, + 544, + 209 + ], + "spans": [ + { + "bbox": [ + 306, + 186, + 544, + 209 + ], + "type": "text", + "content": "When the two cameras can be assumed to have the same focal length " + }, + { + "bbox": [ + 306, + 186, + 544, + 209 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 306, + 186, + 544, + 209 + ], + "type": "text", + "content": ", another constraint is given by" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 359, + 217, + 545, + 230 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 359, + 217, + 545, + 230 + ], + "spans": [ + { + "bbox": [ + 359, + 217, + 545, + 230 + ], + "type": "interline_equation", + "content": "2 F Q F ^ {\\top} Q F Q - \\operatorname {t r} \\left(F Q F ^ {\\top} Q\\right) F Q = 0, \\tag {3}", + "image_path": "c3b5fff7445ab92aecd30f2222106a3a0c24c0090e2e1027e39d66a205d821d8.jpg" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "inline_equation", + "content": "\\mathbb{Q} = \\mathrm{diag}(f^2, f^2, 1)" + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "text", + "content": ". Equation (3) is the necessary and sufficient conditions to recover " + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "inline_equation", + "content": "\\mathbf{R}" + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "inline_equation", + "content": "\\mathbf{t}" + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "text", + "content": " by decomposing " + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "text", + "content": ". Eliminating " + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "text", + "content": ", we can rewrite Eq. (3) in a closed-form w.r.t. " + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 305, + 239, + 545, + 285 + ], + "type": "text", + "content": " [20] as follows:" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 318, + 293, + 545, + 418 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 318, + 293, + 545, + 418 + ], + "spans": [ + { + "bbox": [ + 318, + 293, + 545, + 418 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} h (\\mathbf {F}) = F _ {1 1} F _ {1 3} ^ {3} F _ {3 1} + F _ {1 3} ^ {2} F _ {2 1} F _ {2 3} F _ {3 1} + F _ {1 1} F _ {1 3} F _ {2 3} ^ {2} F _ {3 1} \\\\ + F _ {2 1} F _ {2 3} ^ {3} F _ {3 1} - F _ {1 1} F _ {1 3} F _ {3 1} ^ {3} - F _ {2 1} F _ {2 3} F _ {3 1} ^ {3} + F _ {1 2} F _ {1 3} ^ {3} F _ {3 2} \\\\ + F _ {1 3} ^ {2} F _ {2 2} F _ {2 3} F _ {3 2} + F _ {1 2} F _ {1 3} F _ {2 3} ^ {2} F _ {3 2} + F _ {2 2} F _ {2 3} ^ {3} F _ {3 2} \\\\ - F _ {1 2} F _ {1 3} F _ {3 1} ^ {2} F _ {3 2} - F _ {2 2} F _ {2 3} F _ {3 1} ^ {2} F _ {3 2} - F _ {1 1} F _ {1 3} F _ {3 1} F _ {3 2} ^ {2} \\\\ - F _ {2 1} F _ {2 3} F _ {3 1} F _ {3 2} ^ {2} - F _ {1 2} F _ {1 3} F _ {3 2} ^ {3} - F _ {2 2} F _ {2 3} F _ {3 2} ^ {3} \\tag {4} \\\\ - F _ {1 1} ^ {2} F _ {1 3} ^ {2} F _ {3 3} - F _ {1 2} ^ {2} F _ {1 3} ^ {2} F _ {3 3} - 2 F _ {1 1} F _ {1 3} F _ {2 1} F _ {2 3} F _ {3 3} \\\\ - 2 F _ {1 2} F _ {1 3} F _ {2 2} F _ {2 3} F _ {3 3} - F _ {2 1} ^ {2} F _ {2 3} ^ {2} F _ {3 3} - F _ {2 2} ^ {2} F _ {2 3} ^ {2} F _ {3 3} \\\\ + F _ {1 1} ^ {2} F _ {3 1} ^ {2} F _ {3 3} + F _ {2 1} ^ {2} F _ {3 1} ^ {2} F _ {3 3} + 2 F _ {1 1} F _ {1 2} F _ {3 1} F _ {3 2} F _ {3 3} \\\\ + 2 F _ {2 1} F _ {2 2} F _ {3 1} F _ {3 2} F _ {3 3} + F _ {1 2} ^ {2} F _ {3 2} ^ {2} F _ {3 3} + F _ {2 2} ^ {2} F _ {3 2} ^ {2} F _ {3 3} = 0, \\\\ \\end{array}", + "image_path": "c8085641acae218436285becfb5f46c13f3edfd5f69f98643677282a4540ddb1.jpg" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 306, + 426, + 474, + 437 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 426, + 474, + 437 + ], + "spans": [ + { + "bbox": [ + 306, + 426, + 474, + 437 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 306, + 426, + 474, + 437 + ], + "type": "inline_equation", + "content": "F_{ij}" + }, + { + "bbox": [ + 306, + 426, + 474, + 437 + ], + "type": "text", + "content": " denotes the " + }, + { + "bbox": [ + 306, + 426, + 474, + 437 + ], + "type": "inline_equation", + "content": "(i,j)" + }, + { + "bbox": [ + 306, + 426, + 474, + 437 + ], + "type": "text", + "content": " element of " + }, + { + "bbox": [ + 306, + 426, + 474, + 437 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 306, + 426, + 474, + 437 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 305, + 437, + 545, + 472 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 437, + 545, + 472 + ], + "spans": [ + { + "bbox": [ + 305, + 437, + 545, + 472 + ], + "type": "text", + "content": "Once we obtain an " + }, + { + "bbox": [ + 305, + 437, + 545, + 472 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 305, + 437, + 545, + 472 + ], + "type": "text", + "content": " such that " + }, + { + "bbox": [ + 305, + 437, + 545, + 472 + ], + "type": "inline_equation", + "content": "\\operatorname*{det}(\\mathbb{F}) = 0" + }, + { + "bbox": [ + 305, + 437, + 545, + 472 + ], + "type": "text", + "content": " and Eq. (3) (or Eq. (4)), the focal length " + }, + { + "bbox": [ + 305, + 437, + 545, + 472 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 305, + 437, + 545, + 472 + ], + "type": "text", + "content": " can be computed in a closed-form [20]:" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 321, + 479, + 545, + 545 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 321, + 479, + 545, + 545 + ], + "spans": [ + { + "bbox": [ + 321, + 479, + 545, + 545 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} F _ {1 2} F _ {1 3} F _ {3 3} ^ {2} + F _ {2 2} F _ {2 3} F _ {3 3} ^ {2} \\\\ f ^ {2} = \\frac {- F _ {1 3} ^ {2} F _ {3 2} F _ {3 3} - F _ {2 3} ^ {2} F _ {3 2} F _ {3 3}}{F _ {1 1} F _ {1 3} F _ {3 1} F _ {3 2} + F _ {2 1} F _ {2 3} F _ {3 1} F _ {3 2} + F _ {1 2} F _ {1 3} F _ {3 2} ^ {2}}. \\tag {5} \\\\ + F _ {2 2} F _ {2 3} F _ {3 2} ^ {2} - F _ {1 2} ^ {2} F _ {3 2} F _ {3 3} - F _ {2 2} ^ {2} F _ {3 2} F _ {3 3} \\\\ - F _ {1 1} F _ {1 2} F _ {3 1} F _ {3 3} - F _ {2 1} F _ {2 2} F _ {3 1} F _ {3 3} \\\\ \\end{array}", + "image_path": "fd7eacd7d131c6fc0f9a9b5ed309b7851dbc0ce9b23dfcf13516e3f306d978bb.jpg" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 305, + 552, + 545, + 588 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 552, + 545, + 588 + ], + "spans": [ + { + "bbox": [ + 305, + 552, + 545, + 588 + ], + "type": "text", + "content": "It is well known that the relative motion, " + }, + { + "bbox": [ + 305, + 552, + 545, + 588 + ], + "type": "inline_equation", + "content": "\\mathbf{R}" + }, + { + "bbox": [ + 305, + 552, + 545, + 588 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 552, + 545, + 588 + ], + "type": "inline_equation", + "content": "\\mathbf{t}" + }, + { + "bbox": [ + 305, + 552, + 545, + 588 + ], + "type": "text", + "content": ", can be obtained by using a singular value decomposition [11] or a closed-form method [13]." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 305, + 589, + 545, + 636 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 589, + 545, + 636 + ], + "spans": [ + { + "bbox": [ + 305, + 589, + 545, + 636 + ], + "type": "text", + "content": "If the cameras have a wide angle lens with a radial distortion parameter " + }, + { + "bbox": [ + 305, + 589, + 545, + 636 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 305, + 589, + 545, + 636 + ], + "type": "text", + "content": ", a 2D point " + }, + { + "bbox": [ + 305, + 589, + 545, + 636 + ], + "type": "inline_equation", + "content": "\\mathbf{m}" + }, + { + "bbox": [ + 305, + 589, + 545, + 636 + ], + "type": "text", + "content": " is observed as a radially distorted point " + }, + { + "bbox": [ + 305, + 589, + 545, + 636 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{m}}" + }, + { + "bbox": [ + 305, + 589, + 545, + 636 + ], + "type": "text", + "content": ". The relation can be written by using the division model [10]:" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 363, + 643, + 545, + 681 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 363, + 643, + 545, + 681 + ], + "spans": [ + { + "bbox": [ + 363, + 643, + 545, + 681 + ], + "type": "interline_equation", + "content": "\\mathbf {m} = \\frac {1}{1 + k r} \\hat {\\mathbf {m}} \\propto \\left[ \\begin{array}{c} \\hat {u} \\\\ \\hat {v} \\\\ 1 + k r \\end{array} \\right], \\tag {6}", + "image_path": "b19a88bbd7deed174f36d083a67c125566984b6ccc052ae8e569b73ed40c21be.jpg" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "inline_equation", + "content": "r = \\hat{u}^2 +\\hat{v}^2" + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "content": " . Hereafter, we use the hat symbol " + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\hat{\\cdot}" + }, + { + "bbox": [ + 305, + 689, + 545, + 713 + ], + "type": "text", + "content": " to express radially distorted values." + } + ] + } + ], + "index": 31 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13362" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 71, + 258, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 71, + 258, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 71, + 258, + 85 + ], + "type": "text", + "content": "3. Finding F-matrix with known epipoles" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 91, + 289, + 259 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 91, + 289, + 259 + ], + "spans": [ + { + "bbox": [ + 46, + 91, + 289, + 259 + ], + "type": "text", + "content": "In this section, we propose four different algorithms depending on the number of unknown intrinsic parameters and the number of known epipoles. The basic strategy commonly used in all methods is to parameterize a fundamental matrix " + }, + { + "bbox": [ + 46, + 91, + 289, + 259 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 46, + 91, + 289, + 259 + ], + "type": "text", + "content": " as a linear combination of the null space of a coefficient matrix computed from epipoles and point correspondences. We reduce the number of unknown variables to one and employ Eq. (4) to lead to a higher-order polynomial equation of the single variable. The fundamental matrix " + }, + { + "bbox": [ + 46, + 91, + 289, + 259 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 46, + 91, + 289, + 259 + ], + "type": "text", + "content": " is obtained by substituting the real roots of the polynomial equation into the linear combination of the null space. The null space is derived from the epipoles, and Eq. (4) is used for the root finding, therefore, both the intrinsic and extrinsic parameters can be recovered from the computed " + }, + { + "bbox": [ + 46, + 91, + 289, + 259 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 46, + 91, + 289, + 259 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 266, + 257, + 280 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 266, + 257, + 280 + ], + "spans": [ + { + "bbox": [ + 47, + 266, + 257, + 280 + ], + "type": "text", + "content": "3.1. 2-pt algorithm for " + }, + { + "bbox": [ + 47, + 266, + 257, + 280 + ], + "type": "inline_equation", + "content": "\\mathbf{F} + \\mathbf{f}" + }, + { + "bbox": [ + 47, + 266, + 257, + 280 + ], + "type": "text", + "content": " with two epipoles" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "spans": [ + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "text", + "content": "We start with the simplest case where two epipoles " + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "inline_equation", + "content": "\\mathbf{e}" + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "inline_equation", + "content": "\\mathbf{e}'" + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "text", + "content": " are observed by each camera with an unknown focal length " + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "inline_equation", + "content": "f" + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "text", + "content": " but no lens distortion. If we define the " + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "inline_equation", + "content": "3 \\times 3" + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "text", + "content": " identity matrix by " + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "inline_equation", + "content": "\\mathbf{I}" + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "text", + "content": " and a " + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "inline_equation", + "content": "6 \\times 9" + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "text", + "content": " matrix " + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "inline_equation", + "content": "\\mathbb{N}_1" + }, + { + "bbox": [ + 46, + 285, + 287, + 334 + ], + "type": "text", + "content": " by" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 115, + 340, + 287, + 392 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 115, + 340, + 287, + 392 + ], + "spans": [ + { + "bbox": [ + 115, + 340, + 287, + 392 + ], + "type": "interline_equation", + "content": "\\mathrm {N} _ {1} = \\left[ \\begin{array}{c c c} \\mathbf {e} ^ {\\mathrm {T}} & & \\\\ & \\mathbf {e} ^ {\\mathrm {T}} & \\\\ & & \\mathbf {e} ^ {\\mathrm {T}} \\\\ x ^ {\\prime} \\mathrm {I} & y ^ {\\prime} \\mathrm {I} & \\mathrm {I} \\end{array} \\right], \\tag {7}", + "image_path": "7445c804512a85711b3691cadd7e0041dbaf0d2189a8298a994c605629318cab.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 400, + 185, + 412 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 400, + 185, + 412 + ], + "spans": [ + { + "bbox": [ + 47, + 400, + 185, + 412 + ], + "type": "text", + "content": "Eq. (2) can be written in the form" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 146, + 422, + 287, + 434 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 422, + 287, + 434 + ], + "spans": [ + { + "bbox": [ + 146, + 422, + 287, + 434 + ], + "type": "interline_equation", + "content": "\\mathrm {N} _ {1} \\mathbf {f} = \\mathbf {0}. \\tag {8}", + "image_path": "9d4d931214b93929508b0df864834d0be13633a3b5eafaf58dcda5ffeeb77404.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 444, + 261, + 456 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 444, + 261, + 456 + ], + "spans": [ + { + "bbox": [ + 47, + 444, + 261, + 456 + ], + "type": "text", + "content": "Here, " + }, + { + "bbox": [ + 47, + 444, + 261, + 456 + ], + "type": "inline_equation", + "content": "\\mathbb{N}_1" + }, + { + "bbox": [ + 47, + 444, + 261, + 456 + ], + "type": "text", + "content": " is of size " + }, + { + "bbox": [ + 47, + 444, + 261, + 456 + ], + "type": "inline_equation", + "content": "6\\times 9" + }, + { + "bbox": [ + 47, + 444, + 261, + 456 + ], + "type": "text", + "content": " but its row rank is only five." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 456, + 287, + 480 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 456, + 287, + 480 + ], + "spans": [ + { + "bbox": [ + 47, + 456, + 287, + 480 + ], + "type": "text", + "content": "Utilizing two point correspondences, a " + }, + { + "bbox": [ + 47, + 456, + 287, + 480 + ], + "type": "inline_equation", + "content": "8 \\times 9" + }, + { + "bbox": [ + 47, + 456, + 287, + 480 + ], + "type": "text", + "content": " coefficient matrix " + }, + { + "bbox": [ + 47, + 456, + 287, + 480 + ], + "type": "inline_equation", + "content": "\\mathbb{M}_1" + }, + { + "bbox": [ + 47, + 456, + 287, + 480 + ], + "type": "text", + "content": " is given by" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 117, + 488, + 287, + 528 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 117, + 488, + 287, + 528 + ], + "spans": [ + { + "bbox": [ + 117, + 488, + 287, + 528 + ], + "type": "interline_equation", + "content": "\\mathrm {M} _ {1} = \\left[ \\begin{array}{c} \\mathrm {N} _ {1} \\\\ \\left(\\mathbf {m} _ {1} ^ {\\prime} \\otimes \\mathbf {m} _ {1}\\right) ^ {\\mathsf {T}} \\\\ \\left(\\mathbf {m} _ {2} ^ {\\prime} \\otimes \\mathbf {m} _ {2}\\right) ^ {\\mathsf {T}} \\end{array} \\right]. \\tag {9}", + "image_path": "939d91f97300365e213a5acfe3e62d304c5fd4af735fda38480169ff640c0e91.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 536, + 109, + 546 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 536, + 109, + 546 + ], + "spans": [ + { + "bbox": [ + 47, + 536, + 109, + 546 + ], + "type": "text", + "content": "Then, we have" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 147, + 548, + 287, + 559 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 147, + 548, + 287, + 559 + ], + "spans": [ + { + "bbox": [ + 147, + 548, + 287, + 559 + ], + "type": "interline_equation", + "content": "\\mathrm {M} _ {1} \\mathbf {f} = \\mathbf {0}. \\tag {10}", + "image_path": "783f768cc3ed550b9813a2a8fe3d8250deb0a87cc8d005136e9b36e246a415f0.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "spans": [ + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "type": "text", + "content": "Since the row rank of " + }, + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "type": "inline_equation", + "content": "\\mathsf{M}_1" + }, + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "type": "text", + "content": " is seven, " + }, + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "type": "inline_equation", + "content": "\\mathbf{f}" + }, + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "type": "text", + "content": " can be parameterized by a linear combination of two null vectors " + }, + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "type": "inline_equation", + "content": "\\mathbf{v}_1" + }, + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "type": "inline_equation", + "content": "\\mathbf{v}_2" + }, + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "type": "text", + "content": " of " + }, + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "type": "inline_equation", + "content": "\\mathsf{M}_1" + }, + { + "bbox": [ + 47, + 565, + 287, + 590 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 135, + 600, + 287, + 612 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 135, + 600, + 287, + 612 + ], + "spans": [ + { + "bbox": [ + 135, + 600, + 287, + 612 + ], + "type": "interline_equation", + "content": "\\mathbf {f} = \\alpha \\mathbf {v} _ {2} + \\mathbf {v} _ {1}. \\tag {11}", + "image_path": "8dc2dd7a124adc980a9ef8dfc27a7149208ae6f5b6e1aa5288fe756d0e0e17dc.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 47, + 621, + 287, + 646 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 621, + 287, + 646 + ], + "spans": [ + { + "bbox": [ + 47, + 621, + 287, + 646 + ], + "type": "text", + "content": "Substituting Eq. (11) into Eq. (4), we obtain a fifth-order equation for the single variable " + }, + { + "bbox": [ + 47, + 621, + 287, + 646 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 47, + 621, + 287, + 646 + ], + "type": "text", + "content": ", which is represented by" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 52, + 654, + 287, + 668 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 52, + 654, + 287, + 668 + ], + "spans": [ + { + "bbox": [ + 52, + 654, + 287, + 668 + ], + "type": "interline_equation", + "content": "h (\\mathbb {F} (\\alpha)) = c _ {5} \\alpha^ {5} + c _ {4} \\alpha^ {4} + c _ {3} \\alpha^ {3} + c _ {2} \\alpha^ {2} + c _ {1} \\alpha + c _ {0} = 0. \\tag {12}", + "image_path": "a0282cf0de9d95958b1a4104932bb47b51e1fa4cfdad6a9298451c141787ec9e.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 47, + 677, + 287, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 677, + 287, + 712 + ], + "spans": [ + { + "bbox": [ + 47, + 677, + 287, + 712 + ], + "type": "text", + "content": "Once we found the roots of Eq. (12), the fundamental matrix " + }, + { + "bbox": [ + 47, + 677, + 287, + 712 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 47, + 677, + 287, + 712 + ], + "type": "text", + "content": " is then obtained from Eq. (11). This algorithm gives at most five solutions." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 72, + 522, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 522, + 85 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 522, + 85 + ], + "type": "text", + "content": "3.2. 4-pt algorithm for " + }, + { + "bbox": [ + 306, + 72, + 522, + 85 + ], + "type": "inline_equation", + "content": "\\mathbf{F} + \\mathbf{f}" + }, + { + "bbox": [ + 306, + 72, + 522, + 85 + ], + "type": "text", + "content": " with single epipole" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 305, + 91, + 545, + 152 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 91, + 545, + 152 + ], + "spans": [ + { + "bbox": [ + 305, + 91, + 545, + 152 + ], + "type": "text", + "content": "When one of the two epipoles is only available, we can solve the " + }, + { + "bbox": [ + 305, + 91, + 545, + 152 + ], + "type": "inline_equation", + "content": "\\mathbf{F} + f" + }, + { + "bbox": [ + 305, + 91, + 545, + 152 + ], + "type": "text", + "content": " problem by adding more two point correspondences. Using four point correspondences together with the single epipole " + }, + { + "bbox": [ + 305, + 91, + 545, + 152 + ], + "type": "inline_equation", + "content": "\\mathbf{e}" + }, + { + "bbox": [ + 305, + 91, + 545, + 152 + ], + "type": "text", + "content": ", we can construct a " + }, + { + "bbox": [ + 305, + 91, + 545, + 152 + ], + "type": "inline_equation", + "content": "7 \\times 9" + }, + { + "bbox": [ + 305, + 91, + 545, + 152 + ], + "type": "text", + "content": " coefficient matrix " + }, + { + "bbox": [ + 305, + 91, + 545, + 152 + ], + "type": "inline_equation", + "content": "\\mathbb{M}_2" + }, + { + "bbox": [ + 305, + 91, + 545, + 152 + ], + "type": "text", + "content": " by" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 376, + 163, + 545, + 246 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 376, + 163, + 545, + 246 + ], + "spans": [ + { + "bbox": [ + 376, + 163, + 545, + 246 + ], + "type": "interline_equation", + "content": "\\mathrm {M} _ {2} = \\left[ \\begin{array}{c c c} \\mathbf {e} ^ {\\top} & & \\\\ & \\mathbf {e} ^ {\\top} & \\\\ & & \\mathbf {e} ^ {\\top} \\\\ \\left(\\mathbf {m} _ {1} ^ {\\prime} \\otimes \\mathbf {m} _ {1}\\right) ^ {\\top} & & \\\\ & \\vdots & \\\\ \\left(\\mathbf {m} _ {4} ^ {\\prime} \\otimes \\mathbf {m} _ {4}\\right) ^ {\\top} & & \\end{array} \\right], \\tag {13}", + "image_path": "d070786b167fb945f202320b8dd999b71658cb11d83101d026e4eb43bfcce64d.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 256, + 368, + 266 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 256, + 368, + 266 + ], + "spans": [ + { + "bbox": [ + 306, + 256, + 368, + 266 + ], + "type": "text", + "content": "which satisfies" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 405, + 273, + 545, + 285 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 405, + 273, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 405, + 273, + 545, + 285 + ], + "type": "interline_equation", + "content": "\\mathrm {M} _ {2} \\mathbf {f} = \\mathbf {0}. \\tag {14}", + "image_path": "a5bd0014e003db80f4e37dee4351e2feda8669e226baa5951012d543a448f5a2.jpg" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 305, + 297, + 545, + 344 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 297, + 545, + 344 + ], + "spans": [ + { + "bbox": [ + 305, + 297, + 545, + 344 + ], + "type": "text", + "content": "The row rank of " + }, + { + "bbox": [ + 305, + 297, + 545, + 344 + ], + "type": "inline_equation", + "content": "\\mathbb{M}_2" + }, + { + "bbox": [ + 305, + 297, + 545, + 344 + ], + "type": "text", + "content": " is seven, which is identical to " + }, + { + "bbox": [ + 305, + 297, + 545, + 344 + ], + "type": "inline_equation", + "content": "\\mathbb{M}_1" + }, + { + "bbox": [ + 305, + 297, + 545, + 344 + ], + "type": "text", + "content": ". Consequently, we can find " + }, + { + "bbox": [ + 305, + 297, + 545, + 344 + ], + "type": "inline_equation", + "content": "\\mathbb{F}" + }, + { + "bbox": [ + 305, + 297, + 545, + 344 + ], + "type": "text", + "content": " using exactly the same approach as in Eqs. (11) and (12). The number of the real solutions of this algorithm is at most five." + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 306, + 357, + 528, + 370 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 357, + 528, + 370 + ], + "spans": [ + { + "bbox": [ + 306, + 357, + 528, + 370 + ], + "type": "text", + "content": "3.3. 3-pt algorithm for " + }, + { + "bbox": [ + 306, + 357, + 528, + 370 + ], + "type": "inline_equation", + "content": "\\mathbf{F} + \\mathbf{f} + \\mathbf{k}" + }, + { + "bbox": [ + 306, + 357, + 528, + 370 + ], + "type": "text", + "content": " with two epipoles" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "spans": [ + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "text", + "content": "We address a more complicated problem where a radial distortion parameter " + }, + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 305, + 376, + 545, + 425 + ], + "type": "text", + "content": " is additionally unknown. Since we have two epipoles in this case, this problem can be solved using three point correspondences." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "spans": [ + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "type": "text", + "content": "In this problem, the epipoles, " + }, + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{e}}" + }, + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{e}}^{\\prime}" + }, + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "type": "text", + "content": ", are observed in the distorted image coordinates, as with the point correspondences " + }, + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "type": "inline_equation", + "content": "\\hat{\\mathbf{m}}" + }, + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "type": "text", + "content": ". Using Eq. (6), we can represent the undistorted epipoles, " + }, + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "type": "inline_equation", + "content": "\\mathbf{e}" + }, + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "type": "inline_equation", + "content": "\\mathbf{e}^{\\prime}" + }, + { + "bbox": [ + 305, + 426, + 545, + 475 + ], + "type": "text", + "content": ", as" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 365, + 486, + 545, + 530 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 365, + 486, + 545, + 530 + ], + "spans": [ + { + "bbox": [ + 365, + 486, + 545, + 530 + ], + "type": "interline_equation", + "content": "\\mathbf {e} = \\frac {1}{1 + k z} \\hat {\\mathbf {e}} \\propto \\left[ \\begin{array}{c} \\hat {x} \\\\ \\hat {y} \\\\ 1 + k z \\end{array} \\right], \\tag {15}", + "image_path": "e7dcecff9f29f420ec759802460573617d471d36a91900f16dc4119d45554e9d.jpg" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 364, + 527, + 487, + 564 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 364, + 527, + 487, + 564 + ], + "spans": [ + { + "bbox": [ + 364, + 527, + 487, + 564 + ], + "type": "interline_equation", + "content": "\\mathbf {e} ^ {\\prime} = \\frac {1}{1 + k z ^ {\\prime}} \\hat {\\mathbf {e}} ^ {\\prime} \\propto \\left[ \\begin{array}{c} \\hat {x} ^ {\\prime} \\\\ \\hat {y} ^ {\\prime} \\\\ 1 + k z ^ {\\prime} \\end{array} \\right],", + "image_path": "cee10054fb55239fa0bd85842bc5ce48c87a01afb5374cbcc48b7df2f1be5481.jpg" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 306, + 575, + 545, + 601 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 575, + 545, + 601 + ], + "spans": [ + { + "bbox": [ + 306, + 575, + 545, + 601 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 306, + 575, + 545, + 601 + ], + "type": "inline_equation", + "content": "z = \\hat{x}^2 +\\hat{y}^2" + }, + { + "bbox": [ + 306, + 575, + 545, + 601 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 575, + 545, + 601 + ], + "type": "inline_equation", + "content": "z^{\\prime} = \\hat{x}^{\\prime 2} + \\hat{y}^{\\prime 2}" + }, + { + "bbox": [ + 306, + 575, + 545, + 601 + ], + "type": "text", + "content": " . Note that the radial distortion " + }, + { + "bbox": [ + 306, + 575, + 545, + 601 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 306, + 575, + 545, + 601 + ], + "type": "text", + "content": " is an unknown parameter." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 317, + 602, + 533, + 614 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 602, + 533, + 614 + ], + "spans": [ + { + "bbox": [ + 317, + 602, + 533, + 614 + ], + "type": "text", + "content": "Similar to Eqs. (7) and (8), we can rewrite Eq. (2) by" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 405, + 628, + 545, + 639 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 405, + 628, + 545, + 639 + ], + "spans": [ + { + "bbox": [ + 405, + 628, + 545, + 639 + ], + "type": "interline_equation", + "content": "\\mathrm {N} _ {2} \\mathbf {f} = \\mathbf {0}, \\tag {16}", + "image_path": "8e7f8a4c87f43fef2eea41fbf4e3df6bc2f5e9b1c9b73ae7d78697da847cd729.jpg" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 306, + 653, + 334, + 663 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 653, + 334, + 663 + ], + "spans": [ + { + "bbox": [ + 306, + 653, + 334, + 663 + ], + "type": "text", + "content": "where" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 358, + 665, + 545, + 717 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 358, + 665, + 545, + 717 + ], + "spans": [ + { + "bbox": [ + 358, + 665, + 545, + 717 + ], + "type": "interline_equation", + "content": "\\mathrm {N} _ {2} = \\left[ \\begin{array}{c c c} \\mathbf {e} ^ {\\top} & & \\\\ & \\mathbf {e} ^ {\\top} & \\\\ & & \\mathbf {e} ^ {\\top} \\\\ \\hat {x} ^ {\\prime} \\mathrm {I} & \\hat {y} ^ {\\prime} \\mathrm {I} & (1 + k z ^ {\\prime}) \\mathrm {I} \\end{array} \\right]. \\tag {17}", + "image_path": "02d426d5e3c6718dca4a67fa68969880cd50d66d119ec3b1e50dd02987c87539.jpg" + } + ] + } + ], + "index": 32 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13363" + } + ] + } + ], + "index": 33 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 251, + 85 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 251, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 251, + 85 + ], + "type": "text", + "content": "The null space of " + }, + { + "bbox": [ + 47, + 72, + 251, + 85 + ], + "type": "inline_equation", + "content": "\\mathbb{N}_2" + }, + { + "bbox": [ + 47, + 72, + 251, + 85 + ], + "type": "text", + "content": " can be symbolically given by" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 95, + 71, + 106 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 95, + 71, + 106 + ], + "spans": [ + { + "bbox": [ + 47, + 95, + 71, + 106 + ], + "type": "interline_equation", + "content": "\\mathsf {V} _ {1} =", + "image_path": "81c3bd159659425c13de61796624b55e1962970c207b2a2ba5b054fa00f051fd.jpg" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 50, + 108, + 291, + 227 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 50, + 108, + 291, + 227 + ], + "spans": [ + { + "bbox": [ + 50, + 108, + 291, + 227 + ], + "type": "interline_equation", + "content": "\\left[ \\begin{array}{c c c c} \\hat {y} \\hat {y} ^ {\\prime} & \\hat {y} ^ {\\prime} (1 + k z) & \\hat {y} (1 + k z ^ {\\prime}) & (1 + k z) (1 + k z ^ {\\prime}) \\\\ - \\hat {x} \\hat {y} ^ {\\prime} & 0 & - \\hat {x} (1 + k z ^ {\\prime}) & 0 \\\\ 0 & - \\hat {x} \\hat {y} ^ {\\prime} & 0 & - \\hat {x} (1 + k z ^ {\\prime}) \\\\ - \\hat {x} ^ {\\prime} \\hat {y} & - \\hat {x} ^ {\\prime} (1 + k z) & 0 & 0 \\\\ \\hat {x} \\hat {x} ^ {\\prime} & 0 & 0 & 0 \\\\ 0 & \\hat {x} \\hat {x} ^ {\\prime} & 0 & 0 \\\\ 0 & 0 & - \\hat {x} ^ {\\prime} \\hat {y} & - \\hat {x} ^ {\\prime} (1 + k z) \\\\ 0 & 0 & \\hat {x} \\hat {x} ^ {\\prime} & 0 \\\\ 0 & 0 & 0 & \\hat {x} \\hat {x} ^ {\\prime} \\end{array} \\right] \\tag {18}", + "image_path": "dc331f7772d36724e70c98f7cec95f793fed146d63dd0b3d2091ca0bca225ca4.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 229, + 287, + 252 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 229, + 287, + 252 + ], + "spans": [ + { + "bbox": [ + 47, + 229, + 287, + 252 + ], + "type": "text", + "content": "Thus, the fundamental matrix can be represented as a linear combination of the column vectors of " + }, + { + "bbox": [ + 47, + 229, + 287, + 252 + ], + "type": "inline_equation", + "content": "\\mathrm{V}_1" + }, + { + "bbox": [ + 47, + 229, + 287, + 252 + ], + "type": "text", + "content": ", i.e." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 143, + 262, + 287, + 275 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 262, + 287, + 275 + ], + "spans": [ + { + "bbox": [ + 143, + 262, + 287, + 275 + ], + "type": "interline_equation", + "content": "\\mathbf {f} = \\mathrm {V} _ {1} \\boldsymbol {\\alpha} _ {1}, \\tag {19}", + "image_path": "aa47377c341216570354de2c67378035afc8495b1916b658b9f9f89134db35e5.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 285, + 161, + 296 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 285, + 161, + 296 + ], + "spans": [ + { + "bbox": [ + 47, + 285, + 161, + 296 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 285, + 161, + 296 + ], + "type": "inline_equation", + "content": "\\alpha_{1}" + }, + { + "bbox": [ + 47, + 285, + 161, + 296 + ], + "type": "text", + "content": " is a 4-dim vector." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 297, + 287, + 321 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 297, + 287, + 321 + ], + "spans": [ + { + "bbox": [ + 47, + 297, + 287, + 321 + ], + "type": "text", + "content": "We now have three point correspondences, which satisfy " + }, + { + "bbox": [ + 47, + 297, + 287, + 321 + ], + "type": "inline_equation", + "content": "(\\mathbf{m}_i' \\otimes \\mathbf{m}_i)^\\top \\mathbf{f} = 0" + }, + { + "bbox": [ + 47, + 297, + 287, + 321 + ], + "type": "text", + "content": ". If we define a " + }, + { + "bbox": [ + 47, + 297, + 287, + 321 + ], + "type": "inline_equation", + "content": "3 \\times 4" + }, + { + "bbox": [ + 47, + 297, + 287, + 321 + ], + "type": "text", + "content": " matrix " + }, + { + "bbox": [ + 47, + 297, + 287, + 321 + ], + "type": "inline_equation", + "content": "\\mathsf{G}_1" + }, + { + "bbox": [ + 47, + 297, + 287, + 321 + ], + "type": "text", + "content": " by" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 113, + 329, + 287, + 368 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 113, + 329, + 287, + 368 + ], + "spans": [ + { + "bbox": [ + 113, + 329, + 287, + 368 + ], + "type": "interline_equation", + "content": "\\mathbf {G} _ {1} = \\left[ \\begin{array}{l} \\left(\\mathbf {m} _ {1} ^ {\\prime} \\otimes \\mathbf {m} _ {1}\\right) ^ {\\mathrm {T}} \\\\ \\left(\\mathbf {m} _ {2} ^ {\\prime} \\otimes \\mathbf {m} _ {2}\\right) ^ {\\mathrm {T}} \\\\ \\left(\\mathbf {m} _ {3} ^ {\\prime} \\otimes \\mathbf {m} _ {3}\\right) ^ {\\mathrm {T}} \\end{array} \\right] \\mathrm {V} _ {1}, \\tag {20}", + "image_path": "db4f9bf1e0d17d461468650d11c472e2a84c4c759789b6589740a33dd2079ee9.jpg" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 376, + 90, + 387 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 376, + 90, + 387 + ], + "spans": [ + { + "bbox": [ + 47, + 376, + 90, + 387 + ], + "type": "text", + "content": "we obtain" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 102, + 393, + 287, + 433 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 102, + 393, + 287, + 433 + ], + "spans": [ + { + "bbox": [ + 102, + 393, + 287, + 433 + ], + "type": "interline_equation", + "content": "\\left[ \\begin{array}{l} \\left(\\mathbf {m} _ {1} ^ {\\prime} \\otimes \\mathbf {m} _ {1}\\right) ^ {\\mathsf {T}} \\\\ \\left(\\mathbf {m} _ {2} ^ {\\prime} \\otimes \\mathbf {m} _ {2}\\right) ^ {\\mathsf {T}} \\\\ \\left(\\mathbf {m} _ {3} ^ {\\prime} \\otimes \\mathbf {m} _ {3}\\right) ^ {\\mathsf {T}} \\end{array} \\right] \\mathbf {f} = \\mathbb {G} _ {1} \\boldsymbol {\\alpha} _ {1} = \\mathbf {0}. \\tag {21}", + "image_path": "9dc5239959d22d407163d419f3ea18105c4cef8f76966a6f96e4ca5b416b8752.jpg" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 47, + 441, + 287, + 477 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 441, + 287, + 477 + ], + "spans": [ + { + "bbox": [ + 47, + 441, + 287, + 477 + ], + "type": "text", + "content": "The unknown vector " + }, + { + "bbox": [ + 47, + 441, + 287, + 477 + ], + "type": "inline_equation", + "content": "\\alpha_{1}" + }, + { + "bbox": [ + 47, + 441, + 287, + 477 + ], + "type": "text", + "content": " can be determined as the kernel of " + }, + { + "bbox": [ + 47, + 441, + 287, + 477 + ], + "type": "inline_equation", + "content": "\\mathsf{G}_1" + }, + { + "bbox": [ + 47, + 441, + 287, + 477 + ], + "type": "text", + "content": " up to scale. Since " + }, + { + "bbox": [ + 47, + 441, + 287, + 477 + ], + "type": "inline_equation", + "content": "\\mathsf{G}_1" + }, + { + "bbox": [ + 47, + 441, + 287, + 477 + ], + "type": "text", + "content": " is of size " + }, + { + "bbox": [ + 47, + 441, + 287, + 477 + ], + "type": "inline_equation", + "content": "3\\times 4" + }, + { + "bbox": [ + 47, + 441, + 287, + 477 + ], + "type": "text", + "content": ", the kernel can be symbolically computed as a 4-dim vector:" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 117, + 487, + 287, + 499 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 117, + 487, + 287, + 499 + ], + "spans": [ + { + "bbox": [ + 117, + 487, + 287, + 499 + ], + "type": "interline_equation", + "content": "\\boldsymbol {\\alpha} _ {1} \\propto \\operatorname {K e r} \\left(\\mathrm {G} _ {1}\\right) = \\mathrm {Q} _ {1} \\boldsymbol {\\beta} _ {1}, \\tag {22}", + "image_path": "dfeef1db948f678f14db775b432009e503a062b81b1338b9fff9cafc4957b23b.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "spans": [ + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "type": "inline_equation", + "content": "\\mathbb{Q}_1" + }, + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "type": "text", + "content": " is a " + }, + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "type": "inline_equation", + "content": "4\\times 5" + }, + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "type": "text", + "content": " matrix and " + }, + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "type": "inline_equation", + "content": "\\beta_{1} = [k^{4},k^{3},k^{2},k,1]^{\\top}" + }, + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "type": "text", + "content": ". We can replace " + }, + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "type": "inline_equation", + "content": "\\alpha_{1}" + }, + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "type": "text", + "content": " with " + }, + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "type": "inline_equation", + "content": "\\mathbb{Q}_1\\beta_1" + }, + { + "bbox": [ + 47, + 508, + 287, + 533 + ], + "type": "text", + "content": ", then Eq. (19) can be rewritten as" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 121, + 543, + 287, + 555 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 121, + 543, + 287, + 555 + ], + "spans": [ + { + "bbox": [ + 121, + 543, + 287, + 555 + ], + "type": "interline_equation", + "content": "\\mathbf {f} = \\mathrm {V} _ {1} \\boldsymbol {\\alpha} _ {1} = \\mathrm {V} _ {1} \\mathrm {Q} _ {1} \\boldsymbol {\\beta} _ {1}. \\tag {23}", + "image_path": "17afc196a7f2ea145c9f43dd8ad3c64f2bddea54cc1978c8d031718f37037153.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 47, + 564, + 287, + 589 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 564, + 287, + 589 + ], + "spans": [ + { + "bbox": [ + 47, + 564, + 287, + 589 + ], + "type": "text", + "content": "Plugging Eq. (23) into Eq. (4), we finally obtain a 16th-degree polynomial equation in " + }, + { + "bbox": [ + 47, + 564, + 287, + 589 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 47, + 564, + 287, + 589 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 83, + 597, + 287, + 611 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 83, + 597, + 287, + 611 + ], + "spans": [ + { + "bbox": [ + 83, + 597, + 287, + 611 + ], + "type": "interline_equation", + "content": "h (\\mathbb {F} (k)) = c _ {1 6} k ^ {1 6} + \\dots + c _ {1} k + c _ {0} = 0. \\tag {24}", + "image_path": "f0fa2b5c8670a1fb78ff515daf702538ba2de29f819c0e1ff10b6bad3311905e.jpg" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 47, + 620, + 287, + 654 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 620, + 287, + 654 + ], + "spans": [ + { + "bbox": [ + 47, + 620, + 287, + 654 + ], + "type": "text", + "content": "We can recover " + }, + { + "bbox": [ + 47, + 620, + 287, + 654 + ], + "type": "inline_equation", + "content": "\\mathbf{f}" + }, + { + "bbox": [ + 47, + 620, + 287, + 654 + ], + "type": "text", + "content": " by substituting the real roots of Eq. (24) into Eq. (23). This algorithm provides at most 16 real solutions." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 72, + 534, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 534, + 85 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 534, + 85 + ], + "type": "text", + "content": "3.4. 5-pt algorithm for " + }, + { + "bbox": [ + 306, + 72, + 534, + 85 + ], + "type": "inline_equation", + "content": "\\mathbf{F} + \\mathbf{f} + \\mathbf{k}" + }, + { + "bbox": [ + 306, + 72, + 534, + 85 + ], + "type": "text", + "content": " with single epipole" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 90, + 545, + 148 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 90, + 545, + 148 + ], + "spans": [ + { + "bbox": [ + 304, + 90, + 545, + 148 + ], + "type": "text", + "content": "Given only a single epipole " + }, + { + "bbox": [ + 304, + 90, + 545, + 148 + ], + "type": "inline_equation", + "content": "\\mathbf{e}" + }, + { + "bbox": [ + 304, + 90, + 545, + 148 + ], + "type": "text", + "content": ", we need two additional point pairs to solve the " + }, + { + "bbox": [ + 304, + 90, + 545, + 148 + ], + "type": "inline_equation", + "content": "F + f + k" + }, + { + "bbox": [ + 304, + 90, + 545, + 148 + ], + "type": "text", + "content": " problem. We omit the details of the derivation and describe the differences only because the procedure of this algorithm is basically similar to Sec. 3.3." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 147, + 545, + 195 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 147, + 545, + 195 + ], + "spans": [ + { + "bbox": [ + 304, + 147, + 545, + 195 + ], + "type": "text", + "content": "The null space of " + }, + { + "bbox": [ + 304, + 147, + 545, + 195 + ], + "type": "inline_equation", + "content": "\\left[ \\begin{array}{ccc}\\mathbf{e}^{\\mathsf{T}} & & \\\\ & \\mathbf{e}^{\\mathsf{T}} & \\\\ & & \\mathbf{e}^{\\mathsf{T}} \\end{array} \\right]" + }, + { + "bbox": [ + 304, + 147, + 545, + 195 + ], + "type": "text", + "content": " can be symbolically given by" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 320, + 205, + 343, + 216 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 320, + 205, + 343, + 216 + ], + "spans": [ + { + "bbox": [ + 320, + 205, + 343, + 216 + ], + "type": "interline_equation", + "content": "V _ {2} =", + "image_path": "f4ecb0e71a9688036769e2afe3faecc1cf0fda5d3c4509f76334552e1e51677c.jpg" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 323, + 218, + 545, + 329 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 323, + 218, + 545, + 329 + ], + "spans": [ + { + "bbox": [ + 323, + 218, + 545, + 329 + ], + "type": "interline_equation", + "content": "\\left[ \\begin{array}{c c c c c c} - \\hat {y} & 1 + k z & 0 & 0 & 0 & 0 \\\\ \\hat {x} & 0 & 0 & 0 & 0 & 0 \\\\ 0 & - \\hat {x} & 0 & 0 & 0 & 0 \\\\ 0 & 0 & - \\hat {y} & 1 + k z & 0 & 0 \\\\ 0 & 0 & \\hat {x} & 0 & 0 & 0 \\\\ 0 & 0 & 0 & - \\hat {x} & 0 & 0 \\\\ 0 & 0 & 0 & 0 & - \\hat {y} & 1 + k z \\\\ 0 & 0 & 0 & 0 & \\hat {x} & 0 \\\\ 0 & 0 & 0 & 0 & 0 & - \\hat {x} \\end{array} \\right]. \\tag {25}", + "image_path": "d6cdefb361e662b1144b182cbeb2548fe36a4fc86cabd23017f52349e6ef64ec.jpg" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "spans": [ + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "text", + "content": "Since " + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "inline_equation", + "content": "\\mathbf{V}_2" + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "text", + "content": " is of size " + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "inline_equation", + "content": "9 \\times 6" + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "text", + "content": ", the unknown vector " + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "inline_equation", + "content": "\\alpha_2" + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "text", + "content": " for this problem becomes a 6-dim vector. Using the five point correspondences, " + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "inline_equation", + "content": "\\mathsf{G}_2" + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "text", + "content": " is represented as a " + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "inline_equation", + "content": "5 \\times 6" + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "text", + "content": " matrix, as shown in Eq. (20). Then, we can symbolically obtain the kernel of " + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "inline_equation", + "content": "\\mathsf{G}_2" + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "text", + "content": ", which is given as the matrix-vector product of a " + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "inline_equation", + "content": "6 \\times 6" + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "text", + "content": " matrix " + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "inline_equation", + "content": "\\mathbb{Q}_2" + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "inline_equation", + "content": "\\beta_2 = [k^5, k^4, k^3, k^2, k, 1]^{\\mathrm{T}}" + }, + { + "bbox": [ + 304, + 336, + 545, + 421 + ], + "type": "text", + "content": ". Now we can express the fundamental matrix by" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 398, + 430, + 545, + 443 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 398, + 430, + 545, + 443 + ], + "spans": [ + { + "bbox": [ + 398, + 430, + 545, + 443 + ], + "type": "interline_equation", + "content": "\\mathbf {f} = \\mathrm {V} _ {2} \\mathrm {Q} _ {2} \\beta_ {2}. \\tag {26}", + "image_path": "5e680dc780545c1dd5b606c783058c2662c1d5529c906224f452e1dd6188f888.jpg" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 304, + 452, + 545, + 475 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 452, + 545, + 475 + ], + "spans": [ + { + "bbox": [ + 304, + 452, + 545, + 475 + ], + "type": "text", + "content": "Substituting Eq. (26) into Eq. (4), we finally obtain a 21st-order polynomial equation in " + }, + { + "bbox": [ + 304, + 452, + 545, + 475 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 304, + 452, + 545, + 475 + ], + "type": "text", + "content": ", i.e." + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 341, + 484, + 545, + 498 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 341, + 484, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 341, + 484, + 545, + 498 + ], + "type": "interline_equation", + "content": "h (\\mathbb {F} (k)) = c _ {2 1} k ^ {2 1} + \\dots + c _ {1} k + c _ {0} = 0. \\tag {27}", + "image_path": "5525e9c61fc74afd128c3a90fbfa78af19f60f18a2f89965ae59d91c2be1b001.jpg" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 306, + 506, + 492, + 517 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 506, + 492, + 517 + ], + "spans": [ + { + "bbox": [ + 306, + 506, + 492, + 517 + ], + "type": "text", + "content": "Thus, we can obtain at most 21 real solutions." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 306, + 526, + 432, + 537 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 526, + 432, + 537 + ], + "spans": [ + { + "bbox": [ + 306, + 526, + 432, + 537 + ], + "type": "text", + "content": "3.5. Non-linear refinement" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 304, + 544, + 545, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 544, + 545, + 605 + ], + "spans": [ + { + "bbox": [ + 304, + 544, + 545, + 605 + ], + "type": "text", + "content": "After running a RANSAC scheme, we generally obtain many inlier points and perform a non-linear refinement to polish the accuracy of the parameters. For example, minimizing the symmetric epipolar distance is one of the major cost functions in the literature [11], i.e." + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 315, + 611, + 545, + 653 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 611, + 545, + 653 + ], + "spans": [ + { + "bbox": [ + 315, + 611, + 545, + 653 + ], + "type": "interline_equation", + "content": "L _ {\\text {s y m}} = \\sum_ {i = 1} ^ {n} \\frac {\\left(\\mathbf {m} _ {i} ^ {\\prime} {} ^ {\\top} \\mathbf {F} \\mathbf {m} _ {i}\\right) ^ {2}}{\\left[ \\mathbf {F} \\mathbf {m} _ {i} \\right] _ {1} ^ {2} + \\left[ \\mathbf {F} \\mathbf {m} _ {i} \\right] _ {2} ^ {2}} + \\frac {\\left(\\mathbf {m} _ {i} ^ {\\prime} {} ^ {\\top} \\mathbf {F} \\mathbf {m} _ {i}\\right) ^ {2}}{\\left[ \\mathbf {F} ^ {\\top} \\mathbf {m} _ {i} ^ {\\prime} \\right] _ {1} ^ {2} + \\left[ \\mathbf {F} ^ {\\top} \\mathbf {m} _ {i} ^ {\\prime} \\right] _ {2} ^ {2}}, \\tag {28}", + "image_path": "433a62347f33bb806f3a4b35b4b14ed623cd6f5c3d18deb9ce80dd2a5211b1d0.jpg" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 304, + 654, + 545, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 545, + 677 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 545, + 677 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 654, + 545, + 677 + ], + "type": "inline_equation", + "content": "[\\mathbf{F}\\mathbf{m}_i]_j^2" + }, + { + "bbox": [ + 304, + 654, + 545, + 677 + ], + "type": "text", + "content": " denotes the square of the j-th element of the vector " + }, + { + "bbox": [ + 304, + 654, + 545, + 677 + ], + "type": "inline_equation", + "content": "\\mathbf{F}\\mathbf{m}_i" + }, + { + "bbox": [ + 304, + 654, + 545, + 677 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 304, + 677, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 677, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 677, + 545, + 714 + ], + "type": "text", + "content": "Since we have an initial guess of the focal length of the two images as " + }, + { + "bbox": [ + 304, + 677, + 545, + 714 + ], + "type": "inline_equation", + "content": "f_{1} = f_{2} = f" + }, + { + "bbox": [ + 304, + 677, + 545, + 714 + ], + "type": "text", + "content": ", we can parameterize the fundamental matrix by " + }, + { + "bbox": [ + 304, + 677, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{F} = \\mathrm{diag}(1,1,f_2)\\mathbf{E}\\mathrm{diag}(1,1,f_1)" + } + ] + } + ], + "index": 31 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13364" + } + ] + } + ], + "index": 32 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 286, + 120 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 286, + 120 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 286, + 120 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 72, + 286, + 120 + ], + "type": "inline_equation", + "content": "\\mathbf{E}" + }, + { + "bbox": [ + 47, + 72, + 286, + 120 + ], + "type": "text", + "content": " represents an essential matrix. Thus, we can use the Helmke's method [12] to update " + }, + { + "bbox": [ + 47, + 72, + 286, + 120 + ], + "type": "inline_equation", + "content": "\\mathbf{E}" + }, + { + "bbox": [ + 47, + 72, + 286, + 120 + ], + "type": "text", + "content": " with preserving 5 DoFs. Also, we initialize the lens distortion of the two images by " + }, + { + "bbox": [ + 47, + 72, + 286, + 120 + ], + "type": "inline_equation", + "content": "k_{1} = k_{2} = k" + }, + { + "bbox": [ + 47, + 72, + 286, + 120 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 122, + 286, + 183 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 122, + 286, + 183 + ], + "spans": [ + { + "bbox": [ + 47, + 122, + 286, + 183 + ], + "type": "text", + "content": "However, those typical approaches of the non-linear refinement do not assume that epipoles are known, which in turn may degrade the fundamental matrix obtained by the proposed method. To avoid this issue, we introduce a regularization term of Eq. (2) as follows:" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 111, + 194, + 286, + 212 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 111, + 194, + 286, + 212 + ], + "spans": [ + { + "bbox": [ + 111, + 194, + 286, + 212 + ], + "type": "interline_equation", + "content": "L _ {\\mathrm {e p i}} = \\left\\| \\mathbf {F} \\mathbf {e} \\right\\| ^ {2} + \\left\\| \\mathbf {F} ^ {\\mathsf {T}} \\mathbf {e} ^ {\\prime} \\right\\| ^ {2}. \\tag {29}", + "image_path": "cd9182e66ada4565ac54d27812431cf6e4c7cbabb0ed8da649e379713df8d8f9.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "spans": [ + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "type": "text", + "content": "Note that the epipoles, " + }, + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "type": "inline_equation", + "content": "\\mathbf{e}" + }, + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "type": "inline_equation", + "content": "\\mathbf{e}^{\\prime}" + }, + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "type": "text", + "content": ", are undistorted using Eq. (15) with " + }, + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "type": "inline_equation", + "content": "k_{1}" + }, + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "type": "inline_equation", + "content": "k_{2}" + }, + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "type": "text", + "content": ". In the case of the single epipole, the second term " + }, + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "type": "inline_equation", + "content": "\\left\\| \\mathbf{F}^{\\mathsf{T}}\\mathbf{e}^{\\prime}\\right\\|^{2}" + }, + { + "bbox": [ + 47, + 223, + 286, + 262 + ], + "type": "text", + "content": " is simply dropped." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 262, + 286, + 288 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 262, + 286, + 288 + ], + "spans": [ + { + "bbox": [ + 47, + 262, + 286, + 288 + ], + "type": "text", + "content": "The total cost function of the proposed scheme is given by jointly optimizing " + }, + { + "bbox": [ + 47, + 262, + 286, + 288 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{sym}}" + }, + { + "bbox": [ + 47, + 262, + 286, + 288 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 262, + 286, + 288 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{epi}}" + }, + { + "bbox": [ + 47, + 262, + 286, + 288 + ], + "type": "text", + "content": " with a weight " + }, + { + "bbox": [ + 47, + 262, + 286, + 288 + ], + "type": "inline_equation", + "content": "w" + }, + { + "bbox": [ + 47, + 262, + 286, + 288 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 124, + 300, + 286, + 314 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 124, + 300, + 286, + 314 + ], + "spans": [ + { + "bbox": [ + 124, + 300, + 286, + 314 + ], + "type": "interline_equation", + "content": "L = L _ {\\text {s y m}} + w L _ {\\text {e p i}}. \\tag {30}", + "image_path": "e858e2be9a9cadecce16d7325b0296d5b6555e607479a452aeeb43f8f0f5915c.jpg" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 329, + 196, + 342 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 329, + 196, + 342 + ], + "spans": [ + { + "bbox": [ + 47, + 329, + 196, + 342 + ], + "type": "text", + "content": "4. Degenerate configurations" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 350, + 286, + 411 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 350, + 286, + 411 + ], + "spans": [ + { + "bbox": [ + 47, + 350, + 286, + 411 + ], + "type": "text", + "content": "Analysis of the degenerate configurations is important to avoid ambiguous 3D shape reconstructions and use the proposed method in real applications. Due to limitations of space, we give several simple examples for " + }, + { + "bbox": [ + 47, + 350, + 286, + 411 + ], + "type": "inline_equation", + "content": "\\mathbf{F} + f" + }, + { + "bbox": [ + 47, + 350, + 286, + 411 + ], + "type": "text", + "content": " problem with two known epipoles in this section." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "spans": [ + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "text", + "content": "Degenerate configurations of two-view geometry in general cases have been extensively studied for the past decades [5, 17, 33, 35]. One typical situation that could often occur in practice is forward motion, where both focal length and radial distortion cannot be uniquely determined regardless of the point distributions. Forward motion alone is not the case for the proposed solvers, but forward motion with special point distributions is. One configuration where the proposed 2-point solver for " + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{F} + f" + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "text", + "content": " problem cannot be solved is that two epipoles and two point correspondences are collinear under forward motion. For example, the row rank of " + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "inline_equation", + "content": "\\mathbb{M}_1" + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "text", + "content": " is less than seven in Eq. (9) when " + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{e} = \\mathbf{e}' = [0,0,1]^{\\mathrm{T}}" + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{m}_i = [u_i,0,1]^{\\mathrm{T}}" + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "inline_equation", + "content": "\\mathbf{m}_i' = [-u_i,0,1]^{\\mathrm{T}}" + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "inline_equation", + "content": "i \\in \\{1,2\\}" + }, + { + "bbox": [ + 47, + 413, + 286, + 616 + ], + "type": "text", + "content": ". Another well-known degenerate configuration for the general solvers is that all 3D points are on a plane. However, in our case, unique solutions can be obtained in planar scenes when two epipoles are known [30]." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 618, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 618, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 46, + 618, + 286, + 712 + ], + "type": "text", + "content": "The rigorous conditions can be given by analyzing the rank of submatrices of " + }, + { + "bbox": [ + 46, + 618, + 286, + 712 + ], + "type": "inline_equation", + "content": "\\mathbb{N}_1" + }, + { + "bbox": [ + 46, + 618, + 286, + 712 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 618, + 286, + 712 + ], + "type": "inline_equation", + "content": "\\mathbb{M}_1" + }, + { + "bbox": [ + 46, + 618, + 286, + 712 + ], + "type": "text", + "content": " (" + }, + { + "bbox": [ + 46, + 618, + 286, + 712 + ], + "type": "inline_equation", + "content": "\\mathbb{N}_2" + }, + { + "bbox": [ + 46, + 618, + 286, + 712 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 618, + 286, + 712 + ], + "type": "inline_equation", + "content": "\\mathbb{M}_2" + }, + { + "bbox": [ + 46, + 618, + 286, + 712 + ], + "type": "text", + "content": " for the other problems as well). In other words, we first find epipoles and image points that cause rank deficiency, then link them to actual camera motions and 3D point distributions. However, as reported in the previous studies, it is not easy to reveal all possible ambiguities. We would leave the in-depth discussion to future research." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 306, + 72, + 387, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 72, + 387, + 85 + ], + "spans": [ + { + "bbox": [ + 306, + 72, + 387, + 85 + ], + "type": "text", + "content": "5. Experiments" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 305, + 91, + 545, + 126 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 91, + 545, + 126 + ], + "spans": [ + { + "bbox": [ + 305, + 91, + 545, + 126 + ], + "type": "text", + "content": "This section reports experimental results on synthetic and real data. We conducted all experiments on a PC with Core i7-13700k." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 133, + 403, + 147 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 133, + 403, + 147 + ], + "spans": [ + { + "bbox": [ + 306, + 133, + 403, + 147 + ], + "type": "text", + "content": "5.1. Implementation" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 152, + 545, + 344 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 152, + 545, + 344 + ], + "spans": [ + { + "bbox": [ + 305, + 152, + 545, + 344 + ], + "type": "text", + "content": "We have implemented five conventional methods and the four proposed methods in MATLAB, as shown in Tab. 1. We chose three Gröbner basis solvers that are the state-of-the-art based on the efficient parameterization (Eq. (4)): Larsson's 6-point solver for " + }, + { + "bbox": [ + 305, + 152, + 545, + 344 + ], + "type": "inline_equation", + "content": "\\mathrm{F} + f" + }, + { + "bbox": [ + 305, + 152, + 545, + 344 + ], + "type": "text", + "content": " problem (L6f) [21], Larsson's 7-point solver for " + }, + { + "bbox": [ + 305, + 152, + 545, + 344 + ], + "type": "inline_equation", + "content": "\\mathrm{F} + f + k" + }, + { + "bbox": [ + 305, + 152, + 545, + 344 + ], + "type": "text", + "content": " problem (L7fk) [21], and Martyushev's 7-point solver for " + }, + { + "bbox": [ + 305, + 152, + 545, + 344 + ], + "type": "inline_equation", + "content": "\\mathrm{F} + f + k" + }, + { + "bbox": [ + 305, + 152, + 545, + 344 + ], + "type": "text", + "content": " problem (M7fk) [24]. Those are designed for general scenes, therefore, epipoles are not assumed to be available. Moreover, we used two DLT-based approaches by Ito et al. [14]: the 3-point solver with two epipoles (I3), and the 5-point solver with a single epipole (I5). Although I3 and I5 do not guarantee to satisfy Eq. (3) or Eq. (4), we calculated focal length by simply applying Eq. (5) to a fundamental matrix given by I3 or I5. We used the root function for solving the polynomials of the proposed solvers, i.e. Eqs. (12), (24) and (27)." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 350, + 417, + 361 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 350, + 417, + 361 + ], + "spans": [ + { + "bbox": [ + 306, + 350, + 417, + 361 + ], + "type": "text", + "content": "5.2. Evaluation metrics" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 369, + 545, + 393 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 369, + 545, + 393 + ], + "spans": [ + { + "bbox": [ + 306, + 369, + 545, + 393 + ], + "type": "text", + "content": "We measured the following metrics to quantitatively evaluate the estimation accuracy:" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 399, + 545, + 562 + ], + "type": "list", + "angle": 0, + "index": 21, + "blocks": [ + { + "bbox": [ + 306, + 399, + 544, + 423 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 399, + 544, + 423 + ], + "spans": [ + { + "bbox": [ + 306, + 399, + 544, + 423 + ], + "type": "inline_equation", + "content": "\\epsilon_{\\mathrm{F}}" + }, + { + "bbox": [ + 306, + 399, + 544, + 423 + ], + "type": "text", + "content": " Symmetric epipolar distance in pixels by applying " + }, + { + "bbox": [ + 306, + 399, + 544, + 423 + ], + "type": "inline_equation", + "content": "\\mathbf{F}_{\\mathrm{est}}" + }, + { + "bbox": [ + 306, + 399, + 544, + 423 + ], + "type": "text", + "content": " onto the ground-truth 2D points." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 430, + 502, + 444 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 430, + 502, + 444 + ], + "spans": [ + { + "bbox": [ + 306, + 430, + 502, + 444 + ], + "type": "inline_equation", + "content": "\\epsilon_{f}" + }, + { + "bbox": [ + 306, + 430, + 502, + 444 + ], + "type": "text", + "content": " Relative error by " + }, + { + "bbox": [ + 306, + 430, + 502, + 444 + ], + "type": "inline_equation", + "content": "|f_{\\mathrm{est}} - f_{\\mathrm{gt}}| / f_{\\mathrm{gt}} \\times 100[\\%]" + }, + { + "bbox": [ + 306, + 430, + 502, + 444 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 449, + 545, + 498 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 449, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 306, + 449, + 545, + 498 + ], + "type": "inline_equation", + "content": "\\epsilon_{k}" + }, + { + "bbox": [ + 306, + 449, + 545, + 498 + ], + "type": "text", + "content": " Normalized pixel distance " + }, + { + "bbox": [ + 306, + 449, + 545, + 498 + ], + "type": "inline_equation", + "content": "[\\%]" + }, + { + "bbox": [ + 306, + 449, + 545, + 498 + ], + "type": "text", + "content": " between undistorted coordinates using " + }, + { + "bbox": [ + 306, + 449, + 545, + 498 + ], + "type": "inline_equation", + "content": "k_{\\mathrm{est}}" + }, + { + "bbox": [ + 306, + 449, + 545, + 498 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 306, + 449, + 545, + 498 + ], + "type": "inline_equation", + "content": "k_{\\mathrm{gt}}" + }, + { + "bbox": [ + 306, + 449, + 545, + 498 + ], + "type": "text", + "content": ". 100 points were uniformly sampled, and the mean distance is normalized by the diagonal length of the image." + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 306, + 503, + 533, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 503, + 533, + 529 + ], + "spans": [ + { + "bbox": [ + 306, + 503, + 533, + 529 + ], + "type": "inline_equation", + "content": "\\epsilon_{\\mathrm{R}}" + }, + { + "bbox": [ + 306, + 503, + 533, + 529 + ], + "type": "text", + "content": " Angle-axis error by " + }, + { + "bbox": [ + 306, + 503, + 533, + 529 + ], + "type": "inline_equation", + "content": "\\cos^{-1}\\left(\\frac{\\operatorname{tr}(\\mathbb{R}_{\\mathrm{gt}}^{\\mathrm{T}}\\mathbb{R}_{\\mathrm{est}}) - 1}{2}\\right)" + }, + { + "bbox": [ + 306, + 503, + 533, + 529 + ], + "type": "text", + "content": " [degrees]." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 306, + 536, + 528, + 562 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 536, + 528, + 562 + ], + "spans": [ + { + "bbox": [ + 306, + 536, + 528, + 562 + ], + "type": "inline_equation", + "content": "\\epsilon_{t}" + }, + { + "bbox": [ + 306, + 536, + 528, + 562 + ], + "type": "text", + "content": " Cosine similarity by " + }, + { + "bbox": [ + 306, + 536, + 528, + 562 + ], + "type": "inline_equation", + "content": "\\cos^{-1}\\left(\\frac{\\mathbf{t}_{\\mathrm{gt}}^{\\mathrm{T}}\\mathbf{t}_{\\mathrm{est}}}{\\|\\mathbf{t}_{\\mathrm{gt}}\\| \\|\\mathbf{t}_{\\mathrm{est}}\\|}\\right)" + }, + { + "bbox": [ + 306, + 536, + 528, + 562 + ], + "type": "text", + "content": " [degrees]." + } + ] + } + ], + "index": 20 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 566, + 395, + 578 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 566, + 395, + 578 + ], + "spans": [ + { + "bbox": [ + 306, + 566, + 395, + 578 + ], + "type": "text", + "content": "5.3. Synthetic data" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 306, + 585, + 544, + 609 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 585, + 544, + 609 + ], + "spans": [ + { + "bbox": [ + 306, + 585, + 544, + 609 + ], + "type": "text", + "content": "We investigate the performance of the minimal solvers using synthetic data in this section." + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 306, + 623, + 423, + 635 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 623, + 423, + 635 + ], + "spans": [ + { + "bbox": [ + 306, + 623, + 423, + 635 + ], + "type": "text", + "content": "5.3.1 Scene configuration" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "type": "text", + "content": "We created synthetic scenes as follows. Two cameras were randomly located in the area of " + }, + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "type": "inline_equation", + "content": "5.0\\mathrm{m}\\times 5.0\\mathrm{m}" + }, + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "type": "inline_equation", + "content": "2.0\\mathrm{m}" + }, + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "type": "text", + "content": " high to project each other, as shown in Fig. 1b. Small perturbations within 5 degrees and " + }, + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "type": "inline_equation", + "content": "\\pm 0.2\\mathrm{m}" + }, + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "type": "text", + "content": " were added to the rotation and position of the cameras, respectively. The image resolution was " + }, + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "type": "inline_equation", + "content": "640\\times 480" + }, + { + "bbox": [ + 305, + 642, + 545, + 713 + ], + "type": "text", + "content": ", the focal length was set to" + } + ] + } + ], + "index": 25 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13365" + } + ] + } + ], + "index": 26 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 59, + 70, + 535, + 224 + ], + "blocks": [ + { + "bbox": [ + 59, + 70, + 535, + 224 + ], + "lines": [ + { + "bbox": [ + 59, + 70, + 535, + 224 + ], + "spans": [ + { + "bbox": [ + 59, + 70, + 535, + 224 + ], + "type": "table", + "html": "
MethodReferenceProblemDecomposability Eqs. (3) and (4)# of points# of epipoles# of solutionsApproach
L6f[21]F+f✓6015
L7fk[21]F+f+k✓7068Gröbner basis
M7fk[24]F+f+k✓7068
I5[14]F511DLT
I3[14]F321
P4fF+f✓415
P2fF+f✓225Closed-form
P5fkF+f+k✓5116
P3fkF+f+k✓3221
", + "image_path": "681b22d96a494fd21dfcd2f913f0dcf337a83fd2a24bbf5f677bd96a4a9e1b3e.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "bbox": [ + 209, + 223, + 382, + 234 + ], + "lines": [ + { + "bbox": [ + 209, + 223, + 382, + 234 + ], + "spans": [ + { + "bbox": [ + 209, + 223, + 382, + 234 + ], + "type": "text", + "content": "Table 1. Methods compared in the experiments." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "text" + }, + { + "type": "image", + "bbox": [ + 49, + 244, + 190, + 356 + ], + "blocks": [ + { + "bbox": [ + 49, + 244, + 190, + 356 + ], + "lines": [ + { + "bbox": [ + 49, + 244, + 190, + 356 + ], + "spans": [ + { + "bbox": [ + 49, + 244, + 190, + 356 + ], + "type": "image", + "image_path": "9fb1f99234204473fd039bf3db6b315f9e155a40cf1bc2de96ddd8f77bc55523.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 88, + 360, + 504, + 372 + ], + "lines": [ + { + "bbox": [ + 88, + 360, + 504, + 372 + ], + "spans": [ + { + "bbox": [ + 88, + 360, + 504, + 372 + ], + "type": "text", + "content": "Figure 3. The cumulative histogram of numerical accuracy for " + }, + { + "bbox": [ + 88, + 360, + 504, + 372 + ], + "type": "inline_equation", + "content": "10^{6}" + }, + { + "bbox": [ + 88, + 360, + 504, + 372 + ], + "type": "text", + "content": " trials of randomly generated data without noise." + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 201, + 244, + 340, + 356 + ], + "blocks": [ + { + "bbox": [ + 201, + 244, + 340, + 356 + ], + "lines": [ + { + "bbox": [ + 201, + 244, + 340, + 356 + ], + "spans": [ + { + "bbox": [ + 201, + 244, + 340, + 356 + ], + "type": "image", + "image_path": "7b9d7b60b7cd00909793ab8489f37ca8baf342f81e985ef7e73f1f5c20a6f788.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 351, + 245, + 544, + 357 + ], + "blocks": [ + { + "bbox": [ + 351, + 245, + 544, + 357 + ], + "lines": [ + { + "bbox": [ + 351, + 245, + 544, + 357 + ], + "spans": [ + { + "bbox": [ + 351, + 245, + 544, + 357 + ], + "type": "image", + "image_path": "7b19aa2cc71430f02437ba66449302d9c80a36623cf6ac7d1d9c9aa4722a2418.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 46, + 391, + 287, + 475 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 391, + 287, + 475 + ], + "spans": [ + { + "bbox": [ + 46, + 391, + 287, + 475 + ], + "type": "inline_equation", + "content": "f = 381.3" + }, + { + "bbox": [ + 46, + 391, + 287, + 475 + ], + "type": "text", + "content": ", which is approximately " + }, + { + "bbox": [ + 46, + 391, + 287, + 475 + ], + "type": "inline_equation", + "content": "80^{\\circ}" + }, + { + "bbox": [ + 46, + 391, + 287, + 475 + ], + "type": "text", + "content": " HFOV. The radial lens distortion was set to " + }, + { + "bbox": [ + 46, + 391, + 287, + 475 + ], + "type": "inline_equation", + "content": "k = -0.2 / f^{2}" + }, + { + "bbox": [ + 46, + 391, + 287, + 475 + ], + "type": "text", + "content": " for the " + }, + { + "bbox": [ + 46, + 391, + 287, + 475 + ], + "type": "inline_equation", + "content": "\\mathsf{F} + f + k" + }, + { + "bbox": [ + 46, + 391, + 287, + 475 + ], + "type": "text", + "content": " problem. We uniformly generated 100 3D points in the common viewing frustum of the two cameras and projected the 3D points onto the image plane. Then, we randomly picked the minimal number of the points needed for each method." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 491, + 162, + 503 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 491, + 162, + 503 + ], + "spans": [ + { + "bbox": [ + 47, + 491, + 162, + 503 + ], + "type": "text", + "content": "5.3.2 Numerical stability" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "spans": [ + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "type": "text", + "content": "In the first test, we investigated the numerical stability of the methods in noise free data. Figure 3 summarizes a cumulative histogram of " + }, + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "type": "inline_equation", + "content": "\\epsilon_{\\mathrm{F}}, \\epsilon_{f}" + }, + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "type": "inline_equation", + "content": "\\epsilon_{k}" + }, + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "type": "text", + "content": " over " + }, + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "type": "inline_equation", + "content": "10^{6}" + }, + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "type": "text", + "content": " independent trials. The figure indicates that the proposed methods are numerically stable. Comparing the methods in each categories, we see that P2f and P4f are better than I3, I5, and L6f in the " + }, + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "type": "inline_equation", + "content": "\\mathbf{F} + f" + }, + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "type": "text", + "content": " problem, and P5fk and P3fk are better than L7fk and M7fk in the " + }, + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "type": "inline_equation", + "content": "\\mathbf{F} + f + k" + }, + { + "bbox": [ + 46, + 510, + 288, + 631 + ], + "type": "text", + "content": " problem. Here, it should be noted that L7fk is so unstable as to be impractical. We further investigate this issue in the following experiments." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 647, + 217, + 658 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 647, + 217, + 658 + ], + "spans": [ + { + "bbox": [ + 47, + 647, + 217, + 658 + ], + "type": "text", + "content": "5.3.3 Robustness w.r.t. noise on points" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "content": "To evaluate the robustness against the image noise, we measured the estimation errors by adding the zero-mean Gaussian noise onto point correspondences with the standard deviation " + }, + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "inline_equation", + "content": "0 \\leq \\sigma \\leq 2" + }, + { + "bbox": [ + 46, + 665, + 288, + 715 + ], + "type": "text", + "content": " pixels. In this experiment, the image" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 391, + 545, + 536 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 391, + 545, + 536 + ], + "spans": [ + { + "bbox": [ + 304, + 391, + 545, + 536 + ], + "type": "text", + "content": "noise was not added to the epipoles, that is, the ground-truth values are given for the epipoles. Figure 4 shows the mean error over " + }, + { + "bbox": [ + 304, + 391, + 545, + 536 + ], + "type": "inline_equation", + "content": "10^{5}" + }, + { + "bbox": [ + 304, + 391, + 545, + 536 + ], + "type": "text", + "content": " independent trials for each noise level. From the figure, we see that the proposed methods are the most robust against noise. Since the two DLT methods, I3 and I5, do not consider the decomposability conditions described in Eqs. (3) and (4), their focal length estimation are sensitive to image noise, which is even worse than the general methods, L6f and M7fk. The proposed methods outperform M7fk in estimation of the fundamental matrix and lens distortion while showing comparable accuracy in the focal length estimation." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 306, + 578, + 484, + 590 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 578, + 484, + 590 + ], + "spans": [ + { + "bbox": [ + 306, + 578, + 484, + 590 + ], + "type": "text", + "content": "5.3.4 Robustness w.r.t. noise on epipoles" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "content": "In this experiment, we studied the noise robustness of the six methods using epipoles: two Ito et al.'s and four proposed methods. We added the Gaussian noise on epipoles varying " + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "inline_equation", + "content": "0 \\leq \\sigma \\leq 2" + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "content": " while fixing the image noise as " + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "inline_equation", + "content": "\\sigma = 0.5" + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "content": ". Figure 5 reports the mean error over " + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "inline_equation", + "content": "10^{5}" + }, + { + "bbox": [ + 304, + 605, + 545, + 715 + ], + "type": "text", + "content": " independent trials for each noise level. The results have similar trends to the previous experiments. Among the proposed methods, P4f and P5fk are more robust to image noise than P2f and P4fk because P4f and P5fk utilizes a single epipole." + } + ] + } + ], + "index": 13 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13366" + } + ] + } + ], + "index": 14 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 50, + 71, + 187, + 182 + ], + "blocks": [ + { + "bbox": [ + 50, + 71, + 187, + 182 + ], + "lines": [ + { + "bbox": [ + 50, + 71, + 187, + 182 + ], + "spans": [ + { + "bbox": [ + 50, + 71, + 187, + 182 + ], + "type": "image", + "image_path": "99d89e7e4e9c19cc85c907b3c7ce54016915323b0cd28dfc4f8751582260d8cb.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 106, + 186, + 485, + 198 + ], + "lines": [ + { + "bbox": [ + 106, + 186, + 485, + 198 + ], + "spans": [ + { + "bbox": [ + 106, + 186, + 485, + 198 + ], + "type": "text", + "content": "Figure 4. Mean error w.r.t. the image noise on point correspondences over " + }, + { + "bbox": [ + 106, + 186, + 485, + 198 + ], + "type": "inline_equation", + "content": "10^{5}" + }, + { + "bbox": [ + 106, + 186, + 485, + 198 + ], + "type": "text", + "content": " trials for each noise level." + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 200, + 71, + 339, + 182 + ], + "blocks": [ + { + "bbox": [ + 200, + 71, + 339, + 182 + ], + "lines": [ + { + "bbox": [ + 200, + 71, + 339, + 182 + ], + "spans": [ + { + "bbox": [ + 200, + 71, + 339, + 182 + ], + "type": "image", + "image_path": "8994edff9cdb188bdb4eead015c6c09392db192299040990fea3b24d80fb3968.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 351, + 72, + 543, + 182 + ], + "blocks": [ + { + "bbox": [ + 351, + 72, + 543, + 182 + ], + "lines": [ + { + "bbox": [ + 351, + 72, + 543, + 182 + ], + "spans": [ + { + "bbox": [ + 351, + 72, + 543, + 182 + ], + "type": "image", + "image_path": "5664e932849efbcaf2d8da12b48902f98a13f6b517becc20edfe424d1dd1a4cd.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 50, + 209, + 187, + 319 + ], + "blocks": [ + { + "bbox": [ + 50, + 209, + 187, + 319 + ], + "lines": [ + { + "bbox": [ + 50, + 209, + 187, + 319 + ], + "spans": [ + { + "bbox": [ + 50, + 209, + 187, + 319 + ], + "type": "image", + "image_path": "e134de50c0baa8f25103f622cd72d2c8c5c4238a3ce5843b6563dff8b1c47985.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 131, + 323, + 460, + 335 + ], + "lines": [ + { + "bbox": [ + 131, + 323, + 460, + 335 + ], + "spans": [ + { + "bbox": [ + 131, + 323, + 460, + 335 + ], + "type": "text", + "content": "Figure 5. Mean error w.r.t. the image noise on epipoles over " + }, + { + "bbox": [ + 131, + 323, + 460, + 335 + ], + "type": "inline_equation", + "content": "10^{5}" + }, + { + "bbox": [ + 131, + 323, + 460, + 335 + ], + "type": "text", + "content": " trials for each noise level." + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 200, + 209, + 338, + 319 + ], + "blocks": [ + { + "bbox": [ + 200, + 209, + 338, + 319 + ], + "lines": [ + { + "bbox": [ + 200, + 209, + 338, + 319 + ], + "spans": [ + { + "bbox": [ + 200, + 209, + 338, + 319 + ], + "type": "image", + "image_path": "c8c3686f14bef2207ce398bbb387a47f3fd74aa8ad9fec61e00fdbdd1527d04e.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 351, + 209, + 543, + 319 + ], + "blocks": [ + { + "bbox": [ + 351, + 209, + 543, + 319 + ], + "lines": [ + { + "bbox": [ + 351, + 209, + 543, + 319 + ], + "spans": [ + { + "bbox": [ + 351, + 209, + 543, + 319 + ], + "type": "image", + "image_path": "9c6e1916cbd1677671060efe4a8d3bd5571cf855bf3175d5e89b6e2380cbc5ce.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 69, + 357, + 269, + 483 + ], + "blocks": [ + { + "bbox": [ + 69, + 357, + 269, + 483 + ], + "lines": [ + { + "bbox": [ + 69, + 357, + 269, + 483 + ], + "spans": [ + { + "bbox": [ + 69, + 357, + 269, + 483 + ], + "type": "image", + "image_path": "37b9b09e447e426ed17aecde9705a56f68734e27eacc23d5270077a0ef260501.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 67, + 489, + 265, + 500 + ], + "lines": [ + { + "bbox": [ + 67, + 489, + 265, + 500 + ], + "spans": [ + { + "bbox": [ + 67, + 489, + 265, + 500 + ], + "type": "text", + "content": "Figure 6. Runtime comparison of the minimal solvers." + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_caption" + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 527, + 166, + 539 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 527, + 166, + 539 + ], + "spans": [ + { + "bbox": [ + 47, + 527, + 166, + 539 + ], + "type": "text", + "content": "5.3.5 Computational time" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "spans": [ + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "text", + "content": "Figure 6 shows the mean runtime of all methods over " + }, + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "inline_equation", + "content": "10^{6}" + }, + { + "bbox": [ + 46, + 552, + 287, + 613 + ], + "type": "text", + "content": " independent trials. The computational time of the proposed methods is less than 1 msec, which is not as fast as the Ito et al.'s methods, but is still reasonably fast enough for real-time applications." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 47, + 631, + 115, + 643 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 631, + 115, + 643 + ], + "spans": [ + { + "bbox": [ + 47, + 631, + 115, + 643 + ], + "type": "text", + "content": "5.4. Real data" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 653, + 287, + 715 + ], + "type": "text", + "content": "In this experiments, we incorporated each method into RANSAC together with the non-linear refinement to investigate the performance in real data. We excluded L7fk due to its instability and high computational cost shown in the synthetic data experiments in Sec. 5.3." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 354, + 372, + 365 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 354, + 372, + 365 + ], + "spans": [ + { + "bbox": [ + 306, + 354, + 372, + 365 + ], + "type": "text", + "content": "5.4.1 Dataset" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 373, + 545, + 398 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 373, + 545, + 398 + ], + "spans": [ + { + "bbox": [ + 305, + 373, + 545, + 398 + ], + "type": "text", + "content": "We used two publicly available dataset where multiple cameras are mutually projected:" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 401, + 546, + 486 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 401, + 546, + 486 + ], + "spans": [ + { + "bbox": [ + 306, + 401, + 546, + 486 + ], + "type": "text", + "content": "HumanEva [32] Four RGB cameras with the " + }, + { + "bbox": [ + 306, + 401, + 546, + 486 + ], + "type": "inline_equation", + "content": "656 \\times 490" + }, + { + "bbox": [ + 306, + 401, + 546, + 486 + ], + "type": "text", + "content": " resolution are installed in the corners of a room. The intrinsic parameters are calibrated by Zhang's method, then the extrinsics are calculated using Vicon sensors. A single person is asked to do simple actions such as walking, jogging, etc. There are two combinations of mutual camera projections with two epipoles." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 306, + 491, + 545, + 588 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 491, + 545, + 588 + ], + "spans": [ + { + "bbox": [ + 306, + 491, + 545, + 588 + ], + "type": "text", + "content": "Panoptic studio " + }, + { + "bbox": [ + 306, + 491, + 545, + 588 + ], + "type": "inline_equation", + "content": "[16]^{2}" + }, + { + "bbox": [ + 306, + 491, + 545, + 588 + ], + "type": "text", + "content": " 30 HD cameras, 480 VGA cameras, and 5 Kinect2 are installed on the walls of a domeshaped studio. Both the intrinsic and extrinsic parameters of all cameras are simultaneously calibrated based on the structure-from-motion. All sensors are used for recording multi-person interactions. There are 20 combinations of a single epipole and 80 combinations of two epipoles in the HD cameras." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 591, + 547, + 688 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 591, + 547, + 688 + ], + "spans": [ + { + "bbox": [ + 304, + 591, + 547, + 688 + ], + "type": "text", + "content": "We chose a video sequence from each dataset in which a single person moves around the scene: S2 sequence of HumanEva (Fig. 2a) and dance1 of Panoptic studio (Fig. 2b). Then, 2D human joints on the video frames were detected using OpenPose [7]. The neck and hip joints were selected as the point correspondences because they are less likely to be occluded and are easily observed from any camera. We manually labeled epipole locations in each image." + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 315, + 693, + 467, + 703 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 693, + 467, + 703 + ], + "spans": [ + { + "bbox": [ + 315, + 693, + 467, + 703 + ], + "type": "text", + "content": "1http://humaneva.is.tue.mpg.de/" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 315, + 703, + 495, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 315, + 703, + 495, + 712 + ], + "spans": [ + { + "bbox": [ + 315, + 703, + 495, + 712 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 315, + 703, + 495, + 712 + ], + "type": "text", + "content": "http://domedb.perception.cs.cmu.edu/" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13367" + } + ] + } + ], + "index": 22 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 55, + 70, + 280, + 155 + ], + "blocks": [ + { + "bbox": [ + 55, + 70, + 280, + 155 + ], + "lines": [ + { + "bbox": [ + 55, + 70, + 280, + 155 + ], + "spans": [ + { + "bbox": [ + 55, + 70, + 280, + 155 + ], + "type": "table", + "html": "
MethodεRεtεfεkiter.time
L6f28.014.348.80.7812410.25
M7fk29.815.156.11.4628197.69
I332.816.170.00.26920.04
P2f22.711.348.00.26390.03
P3fk24.712.346.91.111460.04
", + "image_path": "058d486d42b34de5c5f0fbd9be9d6476fe8f92ff226faff41a6387773209a85d.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_body" + } + ], + "index": 0 + }, + { + "type": "table", + "bbox": [ + 51, + 171, + 284, + 256 + ], + "blocks": [ + { + "bbox": [ + 85, + 159, + 249, + 171 + ], + "lines": [ + { + "bbox": [ + 85, + 159, + 249, + 171 + ], + "spans": [ + { + "bbox": [ + 85, + 159, + 249, + 171 + ], + "type": "text", + "content": "(a) HumanEva: S2 (2 epipoles, 2 sequences)" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 51, + 171, + 284, + 256 + ], + "lines": [ + { + "bbox": [ + 51, + 171, + 284, + 256 + ], + "spans": [ + { + "bbox": [ + 51, + 171, + 284, + 256 + ], + "type": "table", + "html": "
MethodεRεtεfεkiter.time
L6f17.38.518.62.70100002.68
M7fk23.812.219.82.611000033.43
I515.512.430.72.69100000.83
P4f11.36.818.02.68100001.22
P5fk11.26.518.22.09100003.64
", + "image_path": "e3fce761d315c29ca8c430cf1af8eb002ee8a23d9de3ed97106a205e6c1e9111.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "table_body" + } + ], + "index": 2 + }, + { + "type": "table", + "bbox": [ + 52, + 272, + 282, + 357 + ], + "blocks": [ + { + "bbox": [ + 58, + 260, + 276, + 272 + ], + "lines": [ + { + "bbox": [ + 58, + 260, + 276, + 272 + ], + "spans": [ + { + "bbox": [ + 58, + 260, + 276, + 272 + ], + "type": "text", + "content": "(b) Panoptic studio: dance1 (single epipole, 20 sequences)" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 52, + 272, + 282, + 357 + ], + "lines": [ + { + "bbox": [ + 52, + 272, + 282, + 357 + ], + "spans": [ + { + "bbox": [ + 52, + 272, + 282, + 357 + ], + "type": "table", + "html": "
MethodεRεtεfεkiter.time
L6f10.34.919.82.67100001.80
M7fk12.05.920.02.851000024.88
I313.18.033.72.6620010.15
P2f6.12.817.72.663180.04
P3fk6.63.217.91.7224380.40
", + "image_path": "55071caaedd56753c28fdfaff416befc70d892ce4cde0b830ab414ce2ff86606.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "table_body" + } + ], + "index": 4 + }, + { + "bbox": [ + 64, + 361, + 270, + 373 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 64, + 361, + 270, + 373 + ], + "spans": [ + { + "bbox": [ + 64, + 361, + 270, + 373 + ], + "type": "text", + "content": "(c) Panoptic studio: dance1 (2 epipoles, 80 sequences)" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 375, + 287, + 418 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 375, + 287, + 418 + ], + "spans": [ + { + "bbox": [ + 46, + 375, + 287, + 418 + ], + "type": "text", + "content": "Table 2. Quantitative results of real image dataset (best in bold and second-best underlined). iter.: the number of RANSAC iterations, time: the total processing time of RANSAC and the non-linear refinement in seconds." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 440, + 165, + 452 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 440, + 165, + 452 + ], + "spans": [ + { + "bbox": [ + 47, + 440, + 165, + 452 + ], + "type": "text", + "content": "5.4.2 Quantitative results" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "spans": [ + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "text", + "content": "For testing the methods, we configured RANSAC to have the threshold by 3 pixels, the confidence by 0.995, and the maximum iteration number by 10000. The random seed was fixed for all methods during a single trial so that the same sample points were drawn. After RANSAC, the nonlinear refinement described in Sec. 3.5 was performed on inliers to polish the camera parameters to be more accurate. The two general solvers, L6f and M7fk, optimized only the symmetric epipolar distance " + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{sym}}" + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "text", + "content": " in Eq. (29). The rest of the solvers utilizing epipoles employed the total cost function " + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "inline_equation", + "content": "L" + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "text", + "content": " in Eq. (30) with a weight " + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "inline_equation", + "content": "w = 100 \\times n" + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "text", + "content": " to balance " + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{sym}}" + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "inline_equation", + "content": "L_{\\mathrm{epi}}" + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "text", + "content": " depending on the number of the points " + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "inline_equation", + "content": "n" + }, + { + "bbox": [ + 46, + 460, + 287, + 605 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "content": "We conducted 100 and 10 trials for each camera pair of S2 and dance1, respectively. Table 2 reports the average values of " + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "inline_equation", + "content": "(\\epsilon_{\\mathrm{R}}, \\epsilon_{\\mathrm{t}}, \\epsilon_{f}, \\epsilon_{k})" + }, + { + "bbox": [ + 46, + 605, + 288, + 714 + ], + "type": "text", + "content": ", the number of RANSAC iterations, and the total processing time. Comparing Tab. 2a with Tabs. 2b and 2c, we can see that all methods show better scores in dance1 even though two epipoles are available in HumanEva. The person in dance1 is captured in the higher-resolution image than in HumanEva, resulting in higher localization accuracy of the 2D joints." + } + ] + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 307, + 70, + 416, + 152 + ], + "blocks": [ + { + "bbox": [ + 307, + 70, + 416, + 152 + ], + "lines": [ + { + "bbox": [ + 307, + 70, + 416, + 152 + ], + "spans": [ + { + "bbox": [ + 307, + 70, + 416, + 152 + ], + "type": "image", + "image_path": "eab72c54270ee1c7cf3c1042e6202a103a6cb67b5e6628fe70e5afa33198b371.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 308, + 156, + 414, + 167 + ], + "lines": [ + { + "bbox": [ + 308, + 156, + 414, + 167 + ], + "spans": [ + { + "bbox": [ + 308, + 156, + 414, + 167 + ], + "type": "text", + "content": "(a) 2D trajectory of the neck." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_caption" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 334, + 178, + 386, + 254 + ], + "blocks": [ + { + "bbox": [ + 334, + 178, + 386, + 254 + ], + "lines": [ + { + "bbox": [ + 334, + 178, + 386, + 254 + ], + "spans": [ + { + "bbox": [ + 334, + 178, + 386, + 254 + ], + "type": "image", + "image_path": "34e72345ef89d82a5ba98e1bbaee4f543903960e2164db9af423de8e0e9906c4.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 337, + 258, + 386, + 269 + ], + "lines": [ + { + "bbox": [ + 337, + 258, + 386, + 269 + ], + "spans": [ + { + "bbox": [ + 337, + 258, + 386, + 269 + ], + "type": "text", + "content": "(c) Top view." + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_caption" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 436, + 71, + 545, + 152 + ], + "blocks": [ + { + "bbox": [ + 436, + 71, + 545, + 152 + ], + "lines": [ + { + "bbox": [ + 436, + 71, + 545, + 152 + ], + "spans": [ + { + "bbox": [ + 436, + 71, + 545, + 152 + ], + "type": "image", + "image_path": "de3e95baf29bedc7e13f0be7e36770923b4097aa2e1db6338a8e270fda81706f.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 436, + 156, + 545, + 178 + ], + "lines": [ + { + "bbox": [ + 436, + 156, + 545, + 178 + ], + "spans": [ + { + "bbox": [ + 436, + 156, + 545, + 178 + ], + "type": "text", + "content": "(b) Reprojection of estimated epipoles (green area in (a))." + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_caption" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 430, + 185, + 543, + 255 + ], + "blocks": [ + { + "bbox": [ + 430, + 185, + 543, + 255 + ], + "lines": [ + { + "bbox": [ + 430, + 185, + 543, + 255 + ], + "spans": [ + { + "bbox": [ + 430, + 185, + 543, + 255 + ], + "type": "image", + "image_path": "4f623994e9868250f22ba0fcd19dc84ad86aeb283cbbcb9834260287631dd827.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 459, + 258, + 511, + 268 + ], + "lines": [ + { + "bbox": [ + 459, + 258, + 511, + 268 + ], + "spans": [ + { + "bbox": [ + 459, + 258, + 511, + 268 + ], + "type": "text", + "content": "(d) Side view." + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 330, + 269, + 521, + 279 + ], + "lines": [ + { + "bbox": [ + 330, + 269, + 521, + 279 + ], + "spans": [ + { + "bbox": [ + 330, + 269, + 521, + 279 + ], + "type": "text", + "content": "Figure 7. 3D shape reconstruction of HumanEva S2." + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_caption" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 307, + 301, + 416, + 363 + ], + "blocks": [ + { + "bbox": [ + 307, + 301, + 416, + 363 + ], + "lines": [ + { + "bbox": [ + 307, + 301, + 416, + 363 + ], + "spans": [ + { + "bbox": [ + 307, + 301, + 416, + 363 + ], + "type": "image", + "image_path": "cbd587f7e36a92494e271d6f4e5be12527e304a2c8a11ff860416dad8155677e.jpg" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 308, + 368, + 414, + 379 + ], + "lines": [ + { + "bbox": [ + 308, + 368, + 414, + 379 + ], + "spans": [ + { + "bbox": [ + 308, + 368, + 414, + 379 + ], + "type": "text", + "content": "(a) 2D trajectory of the neck." + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_caption" + } + ], + "index": 19 + }, + { + "type": "image", + "bbox": [ + 436, + 301, + 545, + 364 + ], + "blocks": [ + { + "bbox": [ + 436, + 301, + 545, + 364 + ], + "lines": [ + { + "bbox": [ + 436, + 301, + 545, + 364 + ], + "spans": [ + { + "bbox": [ + 436, + 301, + 545, + 364 + ], + "type": "image", + "image_path": "0d01220f421f53ae428a3f1e3ec2583b4d14c84f3580a7cb11ea2f11892e9d2e.jpg" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 436, + 368, + 545, + 391 + ], + "lines": [ + { + "bbox": [ + 436, + 368, + 545, + 391 + ], + "spans": [ + { + "bbox": [ + 436, + 368, + 545, + 391 + ], + "type": "text", + "content": "(b) Reprojection of estimated epipoles. (green area in (a))" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_caption" + } + ], + "index": 21 + }, + { + "type": "image", + "bbox": [ + 319, + 390, + 405, + 476 + ], + "blocks": [ + { + "bbox": [ + 319, + 390, + 405, + 476 + ], + "lines": [ + { + "bbox": [ + 319, + 390, + 405, + 476 + ], + "spans": [ + { + "bbox": [ + 319, + 390, + 405, + 476 + ], + "type": "image", + "image_path": "d99c605f1a38e79a23dc15a6752f6e44a8bc6d88f22e50b048e8b15ed42f5a52.jpg" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 336, + 481, + 386, + 491 + ], + "lines": [ + { + "bbox": [ + 336, + 481, + 386, + 491 + ], + "spans": [ + { + "bbox": [ + 336, + 481, + 386, + 491 + ], + "type": "text", + "content": "(c) Top view." + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 306, + 491, + 534, + 502 + ], + "lines": [ + { + "bbox": [ + 306, + 491, + 534, + 502 + ], + "spans": [ + { + "bbox": [ + 306, + 491, + 534, + 502 + ], + "type": "text", + "content": "Figure 8. 3D shape reconstruction of Panoptic studio dance1." + } + ] + } + ], + "index": 27, + "angle": 0, + "type": "image_caption" + } + ], + "index": 23 + }, + { + "type": "image", + "bbox": [ + 438, + 403, + 544, + 476 + ], + "blocks": [ + { + "bbox": [ + 438, + 403, + 544, + 476 + ], + "lines": [ + { + "bbox": [ + 438, + 403, + 544, + 476 + ], + "spans": [ + { + "bbox": [ + 438, + 403, + 544, + 476 + ], + "type": "image", + "image_path": "7462b572e50d9be3959d830517ad7df6bb8798d9e85f74624f2eecac46143d36.jpg" + } + ] + } + ], + "index": 25, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 465, + 481, + 517, + 491 + ], + "lines": [ + { + "bbox": [ + 465, + 481, + 517, + 491 + ], + "spans": [ + { + "bbox": [ + 465, + 481, + 517, + 491 + ], + "type": "text", + "content": "(d) Side view." + } + ] + } + ], + "index": 26, + "angle": 0, + "type": "image_caption" + } + ], + "index": 25 + }, + { + "bbox": [ + 304, + 533, + 545, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 533, + 545, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 533, + 545, + 714 + ], + "type": "text", + "content": "Table 2 indicates that the proposed solvers outperform the conventional methods in either case of one or two epipoles. The proposed solvers show the best or the second-best scores in most evaluation criteria. For example, P2f and P4f are more than 100 times faster than M7fk while achieving lower estimation errors. Although P2f and P4f does not estimate the radial distortion " + }, + { + "bbox": [ + 304, + 533, + 545, + 714 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 304, + 533, + 545, + 714 + ], + "type": "text", + "content": " in RANSAC, the non-linear refinement successfully converges to an accurate solution of " + }, + { + "bbox": [ + 304, + 533, + 545, + 714 + ], + "type": "inline_equation", + "content": "k" + }, + { + "bbox": [ + 304, + 533, + 545, + 714 + ], + "type": "text", + "content": " due to a good initial guess of " + }, + { + "bbox": [ + 304, + 533, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{F}" + }, + { + "bbox": [ + 304, + 533, + 545, + 714 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 533, + 545, + 714 + ], + "type": "inline_equation", + "content": "\\mathbf{f}" + }, + { + "bbox": [ + 304, + 533, + 545, + 714 + ], + "type": "text", + "content": ". On the other hand, in spite of the use of epipoles, I3 and I5 are inferior to the general solvers L6f and M7fk. As reported in Sec. 5.3, two Ito's methods are sensitive to image noise. According to the above observations, we can conclude that satisfying the decomposability conditions, Eqs. (3) and (4), significantly improves the estimation accuracy even with known epipoles." + } + ] + } + ], + "index": 28 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 317, + 757 + ], + "type": "text", + "content": "13368" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 72, + 160, + 85 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 72, + 160, + 85 + ], + "spans": [ + { + "bbox": [ + 47, + 72, + 160, + 85 + ], + "type": "text", + "content": "5.4.3 Qualitative results" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 91, + 289, + 236 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 91, + 289, + 236 + ], + "spans": [ + { + "bbox": [ + 46, + 91, + 289, + 236 + ], + "type": "text", + "content": "Figures 7 and 8 visualize a 3D shape reconstruction of S2 and dance1, respectively. For ease of viewing, only neck joints are shown in both 2D and 3D images. We plotted the position of estimated epipoles over 30 independent trials in Figs. 7b and 8b. The P3fk's epipole and the ground-truth overlap so closely that the difference is not visible. On the other hand, the camera motion given by M7fk has large errors and the epipole is estimated on a different place in each trial. This is consistent with the result in Tab. 2 where the proposed methods have the smallest motion errors. Also, we can visually validate that P3fk reconstructs a 3D shape more accurately than M7fk in Figs. 7c, 7d, 8c and 8d." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 244, + 209, + 257 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 244, + 209, + 257 + ], + "spans": [ + { + "bbox": [ + 47, + 244, + 209, + 257 + ], + "type": "text", + "content": "6. Limitations and future work" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 264, + 289, + 467 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 264, + 289, + 467 + ], + "spans": [ + { + "bbox": [ + 46, + 264, + 289, + 467 + ], + "type": "text", + "content": "One of the limitations is that epipole positions are manually annotated. This is not a critical issue in data set creation (Figs. 2a and 2b) because device installations and data capturing spend time dominantly. However, a fast-automatic epipole detector is required to use the proposed method in real-time applications such as multi-agent Visual-SLAM [28, 29, 36] shown in Figs. 2c and 2d. Although direct epipole estimation has been studied for several decades [2, 8, 22], unfortunately it cannot be said as active nor extensive. We think that the manual labeling is merely a current limitation, which can be resolved by future effort in the computer vision community. For instance, a quick workaround is to place a camera at the center of a colored sphere or circle and detect the camera's center in images by ellipse fitting. Alternatively, there are more sophisticated ways that use wifi/radio waves or IMUs to find the relative locations between devices in 3D space [3]." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 468, + 289, + 552 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 468, + 289, + 552 + ], + "spans": [ + { + "bbox": [ + 46, + 468, + 289, + 552 + ], + "type": "text", + "content": "Another future work is to extend the proposed approach to multi-view geometry, just as Sato [30] extended Ito et al.'s DLT method [14] for obtaining a trifocal or quadrifocal tensor. Combining the multi-view extension with an automatic epipole detector, we can expect that the proposed approach stabilizes multi-agent Visual-SLAM with wide baselines for large-scale scene." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 562, + 119, + 574 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 562, + 119, + 574 + ], + "spans": [ + { + "bbox": [ + 47, + 562, + 119, + 574 + ], + "type": "text", + "content": "7. Conclusion" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 582, + 289, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 289, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 289, + 715 + ], + "type": "text", + "content": "We have presented four minimal solutions to the uncalibrated two-view geometry where one or two epipoles are visible in the image plane. All solvers are manually formulated as higher-order polynomials in a single variable without an automatic Gröbner basis generator. We briefly discussed the degenerate conditions and showed several examples where the proposed solvers are feasible but not the conventional methods. In the experiments, we first compared the proposed solvers with the conventional methods in the numerical stability and robustness against image noise using synthetic data. Then, we demonstrated that the proposed" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 304, + 72, + 547, + 193 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 547, + 193 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 547, + 193 + ], + "type": "text", + "content": "solvers successfully stabilize the structure-from-motion using human joints as point correspondences, which are noisy and less accurate than image feature points. Through these experiments, the proposed solvers outperform the conventional methods in estimation accuracy with maintaining computational efficiency. Finally, we discussed the current limitations of the proposed approach and future work to be applicable in real-time applications. We hope this paper will motivate the computer vision community to develop automatic epipole detectors more extensively." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 202, + 365, + 215 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 202, + 365, + 215 + ], + "spans": [ + { + "bbox": [ + 306, + 202, + 365, + 215 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 307, + 221, + 547, + 713 + ], + "type": "list", + "angle": 0, + "index": 19, + "blocks": [ + { + "bbox": [ + 310, + 221, + 545, + 266 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 310, + 221, + 545, + 266 + ], + "spans": [ + { + "bbox": [ + 310, + 221, + 545, + 266 + ], + "type": "text", + "content": "[1] Sameer Agarwal, Yasutaka Furukawa, Noah Snavely, Ian Simon, Brian Curless, Steven M Seitz, and Richard Szeliski. Building rome in a day. Communications of the ACM, 54(10):105-112, 2011. 1" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 311, + 267, + 547, + 321 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 267, + 547, + 321 + ], + "spans": [ + { + "bbox": [ + 311, + 267, + 547, + 321 + ], + "type": "text", + "content": "[2] Farhoosh Alghabi and Mohsen Soryani. Direct computation of epipoles using two pairs of point-line correspondences. In 2008 Second International Symposium on Intelligent Information Technology Application, volume 3, pages 486-489, 2008. 9" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 311, + 323, + 545, + 367 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 323, + 545, + 367 + ], + "spans": [ + { + "bbox": [ + 311, + 323, + 545, + 367 + ], + "type": "text", + "content": "[3] Safar M Asaad and Halgurd S Maghdid. A comprehensive review of indoor/outdoor localization solutions in IoT era: Research challenges and future perspectives. Computer Networks, page 109041, 2022. 9" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 311, + 368, + 545, + 411 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 368, + 545, + 411 + ], + "spans": [ + { + "bbox": [ + 311, + 368, + 545, + 411 + ], + "type": "text", + "content": "[4] Shai Avidan and Amnon Shashua. Novel view synthesis in tensor space. In Proceedings of IEEE Computer Society Conference on Computer Vision and Pattern Recognition, pages 1034-1040. IEEE, 1997. 1" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 311, + 412, + 545, + 456 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 412, + 545, + 456 + ], + "spans": [ + { + "bbox": [ + 311, + 412, + 545, + 456 + ], + "type": "text", + "content": "[5] GN Newsam DQ Huynh MJ Brooks and HP Pan. Recovering unknown focal lengths in self-calibration: An essentially linear algorithm and degenerate configurations. In Proc. ISPRS-Congress, volume 31, pages 575-580. Citeseer, 1996. 5" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 311, + 457, + 545, + 512 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 457, + 545, + 512 + ], + "spans": [ + { + "bbox": [ + 311, + 457, + 545, + 512 + ], + "type": "text", + "content": "[6] Cesar Cadena, Luca Carlone, Henry Carrillo, Yasir Latif, Davide Scaramuzza, José Neira, Ian Reid, and John J Leonard. Past, present, and future of simultaneous localization and mapping: Toward the robust-perception age. IEEE Transactions on robotics, 32(6):1309-1332, 2016. 1" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 311, + 514, + 545, + 556 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 514, + 545, + 556 + ], + "spans": [ + { + "bbox": [ + 311, + 514, + 545, + 556 + ], + "type": "text", + "content": "[7] Z. Cao, G. Hidalgo Martinez, T. Simon, S. Wei, and Y. A. Sheikh. Openpose: Realtime multi-person 2d pose estimation using part affinity fields. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2019. 7" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 311, + 558, + 545, + 612 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 558, + 545, + 612 + ], + "spans": [ + { + "bbox": [ + 311, + 558, + 545, + 612 + ], + "type": "text", + "content": "[8] Huiqin Chen, Emanuel Aldea, and Sylvie Le Hégarat-Mascle. Determining epipole location integrity by multimodal sampling. In 2019 16th IEEE International Conference on Advanced Video and Signal Based Surveillance (AVSS), pages 1-8. IEEE, 2019. 9" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 311, + 614, + 545, + 657 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 311, + 614, + 545, + 657 + ], + "spans": [ + { + "bbox": [ + 311, + 614, + 545, + 657 + ], + "type": "text", + "content": "[9] Martin A Fischler and Robert C Bolles. Random sample consensus: a paradigm for model fitting with applications to image analysis and automated cartography. Communications of the ACM, 24(6):381-395, 1981. 1" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 658, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 658, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 658, + 545, + 713 + ], + "type": "text", + "content": "[10] Andrew W Fitzgibbon. Simultaneous linear estimation of multiple view geometry and lens distortion. In Proceedings of the 2001 IEEE Computer Society Conference on Computer Vision and Pattern Recognition. CVPR 2001, volume 1, pages I-I. IEEE, 2001. 2" + } + ] + } + ], + "index": 18 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "13369" + } + ] + } + ], + "index": 20 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 713 + ], + "type": "list", + "angle": 0, + "index": 14, + "blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "spans": [ + { + "bbox": [ + 48, + 72, + 287, + 106 + ], + "type": "text", + "content": "[11] Richard I. Hartley and Andrew Zisserman. Multiple View Geometry in Computer Vision. Cambridge University Press, ISBN: 0521540518, second edition, 2004. 1, 2, 4" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 107, + 287, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 107, + 287, + 150 + ], + "spans": [ + { + "bbox": [ + 48, + 107, + 287, + 150 + ], + "type": "text", + "content": "[12] Uwe Helmke, Knut Hüper, Pei Yean Lee, and John Moore. Essential matrix estimation using gauss-newton iterations on a manifold. International Journal of Computer Vision, 74(2):117-136, 2007. 5" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 152, + 287, + 174 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 152, + 287, + 174 + ], + "spans": [ + { + "bbox": [ + 48, + 152, + 287, + 174 + ], + "type": "text", + "content": "[13] Berthold KP Horn. Recovering baseline and orientation from essential matrix. J. Opt. Soc. Am, 110, 1990. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 175, + 287, + 218 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 175, + 287, + 218 + ], + "spans": [ + { + "bbox": [ + 48, + 175, + 287, + 218 + ], + "type": "text", + "content": "[14] M. Ito, T. Sugimura, and J. Sato. Recovering structures and motions from mutual projection of cameras. In 2002 International Conference on Pattern Recognition, volume 3, pages 676-679 vol.3, 2002. 1, 5, 6, 9" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 220, + 287, + 263 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 220, + 287, + 263 + ], + "spans": [ + { + "bbox": [ + 48, + 220, + 287, + 263 + ], + "type": "text", + "content": "[15] Fangyuan Jiang, Yubin Kuang, Jan Erik Solem, and Kalle Åström. A minimal solution to relative pose with unknown focal length and radial distortion. In Asian Conference on Computer Vision, pages 443-456. Springer, 2014. 1" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 265, + 287, + 330 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 265, + 287, + 330 + ], + "spans": [ + { + "bbox": [ + 48, + 265, + 287, + 330 + ], + "type": "text", + "content": "[16] Hanbyul Joo, Hao Liu, Lei Tan, Lin Gui, Bart Nabbe, Iain Matthews, Takeo Kanade, Shohei Nobuhara, and Yaser Sheikh. Panoptic studio: A massively multiview system for social motion capture. In Proceedings of the IEEE International Conference on Computer Vision, pages 3334-3342, 2015. 2, 7" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 332, + 287, + 375 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 332, + 287, + 375 + ], + "spans": [ + { + "bbox": [ + 48, + 332, + 287, + 375 + ], + "type": "text", + "content": "[17] Kenichi Kanatani and Chikara Matsunaga. Closed-form expression for focal lengths from the fundamental matrix. In Proc. 4th Asian Conf. Comput. Vision, volume 1, pages 128-133. CiteSeer, 2000. 5" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 377, + 287, + 431 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 377, + 287, + 431 + ], + "spans": [ + { + "bbox": [ + 48, + 377, + 287, + 431 + ], + "type": "text", + "content": "[18] Yubin Kuang, Jan E Solem, Fredrik Kahl, and Kalle Astrom. Minimal solvers for relative pose with a single unknown radial distortion. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 33-40, 2014. 1" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 434, + 287, + 487 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 434, + 287, + 487 + ], + "spans": [ + { + "bbox": [ + 48, + 434, + 287, + 487 + ], + "type": "text", + "content": "[19] Zuzana Kukelova, Martin Bujnak, and Tomas Pajdla. Polynomial eigenvalue solutions to the 5-pt and 6-pt relative pose problems. In Proceedings of the British Machine Vision Conference, pages 56.1-56.10. BMVA Press, 2008. doi:10.5244/C.22.56.1" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 489, + 287, + 543 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 489, + 287, + 543 + ], + "spans": [ + { + "bbox": [ + 48, + 489, + 287, + 543 + ], + "type": "text", + "content": "[20] Zuzana Kukelova, Joe Kileel, Bernd Sturmfels, and Tomas Pajdla. A clever elimination strategy for efficient minimal solvers. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 4912-4921, 2017. 2" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 545, + 287, + 599 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 545, + 287, + 599 + ], + "spans": [ + { + "bbox": [ + 48, + 545, + 287, + 599 + ], + "type": "text", + "content": "[21] Viktor Larsson, Kalle Astrom, and Magnus Oskarsson. Efficient solvers for minimal problems by syzygy-based reduction. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 820-829, 2017. 1, 5, 6" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 601, + 287, + 644 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 601, + 287, + 644 + ], + "spans": [ + { + "bbox": [ + 48, + 601, + 287, + 644 + ], + "type": "text", + "content": "[22] Jonathan Lawn and Roberto Cipolla. Epipole estimation using affine motion parallax. In Proceedings of the British Machine Vision Conference, pages 38.1-38.10. BMVA Press, 1993. doi:10.5244/C.7.38.9" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 647, + 287, + 679 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 647, + 287, + 679 + ], + "spans": [ + { + "bbox": [ + 48, + 647, + 287, + 679 + ], + "type": "text", + "content": "[23] Hongdong Li. A simple solution to the six-point two-view focal-length problem. In European Conference on Computer Vision, pages 200-213. Springer, 2006. 1" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 681, + 287, + 713 + ], + "type": "text", + "content": "[24] Evgeniy Martyushev, Jana Vrablikova, and Tomas Pajdla. Optimizing elimination templates by greedy parameter search. In Proceedings of the IEEE/CVF Conference" + } + ] + } + ], + "index": 13 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 632 + ], + "type": "list", + "angle": 0, + "index": 28, + "blocks": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "spans": [ + { + "bbox": [ + 327, + 73, + 545, + 95 + ], + "type": "text", + "content": "on Computer Vision and Pattern Recognition, pages 15754-15764, 2022. 5, 6" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 307, + 96, + 545, + 150 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 96, + 545, + 150 + ], + "spans": [ + { + "bbox": [ + 307, + 96, + 545, + 150 + ], + "type": "text", + "content": "[25] Ben Mildenhall, Pratul P Srinivasan, Matthew Tancik, Jonathan T Barron, Ravi Ramamoorthi, and Ren Ng. Nerf: Representing scenes as neural radiance fields for view synthesis. In European conference on computer vision, pages 405-421. Springer, 2020. 1" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 307, + 152, + 545, + 194 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 152, + 545, + 194 + ], + "spans": [ + { + "bbox": [ + 307, + 152, + 545, + 194 + ], + "type": "text", + "content": "[26] Raul Mur-Artal, Jose Maria Martinez Montiel, and Juan D Tardos. Orb-slam: a versatile and accurate monocular slam system. IEEE transactions on robotics, 31(5):1147-1163, 2015. 1" + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 307, + 197, + 545, + 229 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 197, + 545, + 229 + ], + "spans": [ + { + "bbox": [ + 307, + 197, + 545, + 229 + ], + "type": "text", + "content": "[27] David Nister and Frederik Schaffalitzky. Four points in two or three calibrated views: Theory and practice. International Journal of Computer Vision, 67:211-231, 2006. 1" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 307, + 231, + 545, + 285 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 231, + 545, + 285 + ], + "spans": [ + { + "bbox": [ + 307, + 231, + 545, + 285 + ], + "type": "text", + "content": "[28] Jacob M Perron, Rui Huang, Jack Thomas, Lingkang Zhang, Ping Tan, and Richard T Vaughan. Orbiting a moving target with multi-robot collaborative visual slam. In Proceedings of the Workshop on Multi-View Geometry in Robotics (MVI-GRO), Rome, Italy, pages 1339–1344, 2015. 2, 9" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 286, + 545, + 341 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 286, + 545, + 341 + ], + "spans": [ + { + "bbox": [ + 307, + 286, + 545, + 341 + ], + "type": "text", + "content": "[29] Thomas Pollok and Eduardo Monari. A visual slam-based approach for calibration of distributed camera networks. In 2016 13th IEEE International Conference on Advanced Video and Signal Based Surveillance (AVSS), pages 429-437, 2016. 2, 9" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 342, + 545, + 374 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 342, + 545, + 374 + ], + "spans": [ + { + "bbox": [ + 307, + 342, + 545, + 374 + ], + "type": "text", + "content": "[30] Jun Sato. Recovering multiple view geometry from mutual projections of multiple cameras. International Journal of Computer Vision, 66(2):123-140, 2006. 1, 5, 9" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 376, + 545, + 409 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 376, + 545, + 409 + ], + "spans": [ + { + "bbox": [ + 307, + 376, + 545, + 409 + ], + "type": "text", + "content": "[31] Johannes Lutz Schonberger and Jan-Michael Frahm. Structure-from-motion revisited. In Conference on Computer Vision and Pattern Recognition (CVPR), 2016. 1" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 410, + 545, + 463 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 410, + 545, + 463 + ], + "spans": [ + { + "bbox": [ + 307, + 410, + 545, + 463 + ], + "type": "text", + "content": "[32] Leonid Sigal, Alexandru O Balan, and Michael J Black. Humaneva: Synchronized video and motion capture dataset and baseline algorithm for evaluation of articulated human motion. International journal of computer vision, 87(1):4-27, 2010. 2, 7" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 465, + 545, + 498 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 465, + 545, + 498 + ], + "spans": [ + { + "bbox": [ + 307, + 465, + 545, + 498 + ], + "type": "text", + "content": "[33] Carsten Steger. Estimating the fundamental matrix under pure translation and radial distortion. ISPRS Journal of Photogrammetry and Remote Sensing, 74:202-217, 2012. 5" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 499, + 545, + 543 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 499, + 545, + 543 + ], + "spans": [ + { + "bbox": [ + 307, + 499, + 545, + 543 + ], + "type": "text", + "content": "[34] Henrik Stewénius, David Nister, Fredrik Kahl, and Frederik Schaffalitzky. A minimal solution for relative pose with unknown focal length. Image and Vision Computing, 26(7):871-877, 2008. 1" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 544, + 545, + 587 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 544, + 545, + 587 + ], + "spans": [ + { + "bbox": [ + 307, + 544, + 545, + 587 + ], + "type": "text", + "content": "[35] Changchang Wu. Critical configurations for radial distortion self-calibration. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, pages 25-32, 2014. 5" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 589, + 545, + 632 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 589, + 545, + 632 + ], + "spans": [ + { + "bbox": [ + 307, + 589, + 545, + 632 + ], + "type": "text", + "content": "[36] Danping Zou and Ping Tan. Coslam: Collaborative visual slam in dynamic environments. IEEE Transactions on Pattern Analysis and Machine Intelligence, 35(2):354-366, 2013. 2, 9" + } + ] + } + ], + "index": 27 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 294, + 748, + 318, + 757 + ], + "type": "text", + "content": "13370" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file diff --git a/2023/Minimum Latency Deep Online Video Stabilization/5c08d8de-7fcf-430c-a7d0-16aae326aed4_content_list.json b/2023/Minimum Latency Deep Online Video Stabilization/5c08d8de-7fcf-430c-a7d0-16aae326aed4_content_list.json new file mode 100644 index 0000000000000000000000000000000000000000..fbe7539c38f0ae2d1a5ca103c1ebd21a896d3f7b --- /dev/null +++ b/2023/Minimum Latency Deep Online Video Stabilization/5c08d8de-7fcf-430c-a7d0-16aae326aed4_content_list.json @@ -0,0 +1,1891 @@ +[ + { + "type": "text", + "text": "Minimum Latency Deep Online Video Stabilization", + "text_level": 1, + "bbox": [ + 225, + 130, + 743, + 152 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Zhuofan Zhang $^{1*}$ Zhen Liu $^{2*}$ Ping Tan $^{3}$ Bing Zeng $^{1}$ Shuaicheng Liu $^{1,2\\dagger}$ $^{1}$ University of Electronic Science and Technology of China $^{2}$ Megvii Technology \n $^{3}$ The Hong Kong University of Science and Technology", + "bbox": [ + 135, + 186, + 836, + 241 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "{zhangzf98@std., eezeng@, liushuaicheng@}uestc.edu.cn, liuzhen03@megvii.com, pingtan@ust.hk", + "bbox": [ + 245, + 243, + 720, + 276 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Abstract", + "text_level": 1, + "bbox": [ + 233, + 311, + 313, + 328 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "We present a novel camera path optimization framework for the task of online video stabilization. Typically, a stabilization pipeline consists of three steps: motion estimating, path smoothing, and novel view rendering. Most previous methods concentrate on motion estimation, proposing various global or local motion models. In contrast, path optimization receives relatively less attention, especially in the important online setting, where no future frames are available. In this work, we adopt recent off-the-shelf high-quality deep motion models for motion estimation to recover the camera trajectory and focus on the latter two steps. Our network takes a short 2D camera path in a sliding window as input and outputs the stabilizing warp field of the last frame in the window, which warps the coming frame to its stabilized position. A hybrid loss is well-defined to constrain the spatial and temporal consistency. In addition, we build a motion dataset that contains stable and unstable motion pairs for the training. Extensive experiments demonstrate that our approach significantly outperforms state-of-the-art online methods both qualitatively and quantitatively and achieves comparable performance to offline methods. Our code and dataset are available at https://github.com/1iuzhen03/NNDVS.", + "bbox": [ + 75, + 343, + 473, + 691 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "1. Introduction", + "text_level": 1, + "bbox": [ + 76, + 719, + 209, + 734 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "Video stabilization methods aim at removing unwanted shaky motions of a video caused by unsteady moving capture [6]. Traditional methods often take three main steps: 1) camera motion estimating for trajectory recovery; 2) camera path smoothing; and 3) steady frame synthesis. According to the adopted motion model in the first step, these methods can be broadly classified as 2D or 3D. 2D methods adopt planar motion models such as affine [5], or homog-", + "bbox": [ + 75, + 744, + 468, + 867 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/449348ad10987f8b6c931b47b383dd675705882a671aed3ada8357c1b4715c65.jpg", + "image_caption": [ + "(a) Illustration of the dataset synthesis process." + ], + "image_footnote": [], + "bbox": [ + 506, + 313, + 885, + 373 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/4bc2f3f7163e496eb982983f88e49cc3d493363aa8aa460c044ffc6b8ce04316.jpg", + "image_caption": [ + "(b) Illustration of the synthesized camera path." + ], + "image_footnote": [], + "bbox": [ + 503, + 407, + 694, + 489 + ], + "page_idx": 0 + }, + { + "type": "image", + "img_path": "images/05e2eb8628669596f644c9ca8a5c3774a1d3dbdd856941d93dff85b9647f9281.jpg", + "image_caption": [ + "Figure 1. Illustration of the dataset synthesis process (a) and the synthesized camera path (b). We transfer an unstable path to a stable path, creating a synthesized path, which shares high frequencies of the unstable path with low frequencies of the stable path." + ], + "image_footnote": [], + "bbox": [ + 699, + 407, + 888, + 489 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "raphy [27], or mesh [25, 22, 33], or flow [26, 20, 41], while 3D methods resort to 3D depth [23, 17], or reconstructed points [18], or epipolar geometry constraints [3].", + "bbox": [ + 496, + 597, + 890, + 643 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In comparison, deep learning-based methods learn stabilization models from stable and unstable video pairs [33, 41, 35] without explicit steps of motion estimation and smoothing. However, the results of deep methods are often visually inferior to those of traditional ones. A potential reason is that these methods try to learn the three steps all in a unified framework, each of which has different characteristics but is learned in the network blindly.", + "bbox": [ + 496, + 643, + 892, + 763 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "On the other hand, deep affine [12], deep homography [38, 8], and deep mesh models [39, 24, 21, 28] have demonstrated high-quality image registration, even under adverse cases. They are robust to scenes with large depth variation, large dynamic objects, and poor textures, fitting perfectly for the camera motion estimation. In this work, we argue that it is not necessary to enclose all three steps of the stabilization into the learning pipeline, but let the motion estimation to the recent deep motion models [39, 24].", + "bbox": [ + 496, + 763, + 893, + 901 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "CVF", + "bbox": [ + 106, + 2, + 181, + 42 + ], + "page_idx": 0 + }, + { + "type": "header", + "text": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore.", + "bbox": [ + 238, + 0, + 807, + 46 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "*Equal contribution", + "bbox": [ + 94, + 875, + 202, + 887 + ], + "page_idx": 0 + }, + { + "type": "page_footnote", + "text": "† Corresponding author", + "bbox": [ + 96, + 887, + 218, + 898 + ], + "page_idx": 0 + }, + { + "type": "page_number", + "text": "23030", + "bbox": [ + 478, + 944, + 519, + 957 + ], + "page_idx": 0 + }, + { + "type": "text", + "text": "In this way, our network only focuses on learning to stabilize the shaky camera motion, which makes the learning process much more efficient and effective.", + "bbox": [ + 75, + 90, + 468, + 136 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Camera path smoothing can be performed offline or online, where the former optimizes the path globally while the latter smooths the path on-the-fly. In other words, offline approaches have access to all past and future frames during optimization, as it often stabilizes a video after it is captured. In contrast, online methods aim to stabilize a video during the capture. Note that, the concept of real-time differs from that of online, as an online method must be in real-time whereas an offline method can run at real-time speed. The main distinction is the availability of future frames.", + "bbox": [ + 75, + 138, + 467, + 287 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Most existing methods are offline [25, 5, 4, 34, 26]. However, the online setting is critical as many applications desire instant visual feedback based on live video streams [22, 33]. Normally, with limited or even no access to future frames, online methods cannot achieve equal stability as offline methods, particularly in the suppression of the low-frequency camera shake, which frequently necessitates a long camera path. One may argue that online methods can have all the past frames for processing. However, future motions are important, if not more important than the past. Because, for one thing, fast camera motions can happen at any time suddenly, e.g., quick rotation or zooming. The reaction time is short. Inappropriate processing may either decrease the stability or create artifacts such as excessive cropping. For another, all the past frames have already been shown to the audience, meaning that they are fixed, and thus cannot be modified. We can only adjust the unstabled future frames to the frozen past ones.", + "bbox": [ + 75, + 291, + 467, + 561 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "To this end, we propose a deep online camera path smooth network that takes a pre-estimated short 2D camera trajectory in a sliding window as input and outputs the motion compensation warp field of the last frame in the window for the stabilized view, which is the setting of online stabilization with the minimum latency. A video can be stabilized on the fly by applying our model repeatedly for every incoming frame. To deal with depth changes and moving objects, we employ the mesh-based motion model [39] which demonstrates excellent robustness in various scenes. Instead of directly inputting the mesh structure or mesh cells as local homographies to the network, we convert the estimated motion to a dense flow field, which can be fed into the convolutional neural network naturally. We show that it is a more convenient representation compared to other alternatives, e.g., vertex sparse motion vectors or homography matrix, which cannot be easily adapted as input to CNNs. Based on that, we further propose a hybrid loss, which consists of the motion-consistency loss, the shape-consistency loss, and the scale-preserving loss, to maintain the spatial coherence and temporal continuity of the stabilized video.", + "bbox": [ + 75, + 565, + 467, + 882 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Besides, we create a motion dataset, MotionStab, to", + "bbox": [ + 96, + 885, + 467, + 898 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "train our network. In particular, we capture 110 stable videos with a cell phone mounted on a hand-held physical stabilizer. Then, we create a shaky video by transforming each frame of the stable video according to the motion of another irrelevant shaky video. In this way, the stable and unstable motion pairs can be constructed. Fig. 1 shows our idea. Note that, our dataset is different from DeepStab [33], which is captured by a stable and a shaky camera simultaneously. We directly transfer the motion of a shaky video to a stable video. The contents of the two videos are not important but the motion does. That means DeepStab [33] offers frame pairs, while our MotionStab offers motion pairs. We feed the motions to the network instead of RGB frames.", + "bbox": [ + 496, + 90, + 890, + 285 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "The benefits are three folds: 1) image contents are diverse, while motion mappings are much easier to learn; 2) motion as mesh is lightweight, so does the network; 3) the network can be more focused by excluding the task of the motion estimation. As a result, we show that this motion learning pipeline is effective enough, such that it can work with straightforward network architectures, e.g., UNet, without help from more advanced designs or sophisticated modules. Complex motion types can be learned by the network successfully, as long as they exist in the training data. As such, the network can be kept simple yet effective.", + "bbox": [ + 496, + 287, + 890, + 453 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "In summary, the main contributions of this paper are concluded as follows:", + "bbox": [ + 498, + 454, + 890, + 483 + ], + "page_idx": 1 + }, + { + "type": "list", + "sub_type": "text", + "list_items": [ + "- We propose a novel deep camera path optimization framework for online video stabilization.", + "- We propose a hybrid loss to enable robust supervision for maintaining the spatial and temporal coherence of the stabilized video.", + "- We build a comprehensive MotionStab dataset that covers various motions for camera path optimization.", + "- We conduct extensive experiments to demonstrate the effectiveness of the proposed approach against existing state-of-the-art online and offline methods." + ], + "bbox": [ + 517, + 496, + 890, + 683 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2. Related Works", + "text_level": 1, + "bbox": [ + 500, + 700, + 648, + 715 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "2.1. Traditional Methods", + "text_level": 1, + "bbox": [ + 500, + 724, + 692, + 739 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "Early 2D approaches track image features for several frames and then smooth these feature trajectories to stabilize a video [16, 34]. However, long feature tracks [31] are hard to be obtained when large camera motions exist. Later, motion models, such as affine [5] or homography [27, 2], are calculated between neighboring frames, relaxing the requirement of long feature tracks into feature matches [30] between adjacent frames. Then, these motion models are accumulated to generate a 2D camera trajectory, which is shown to be a good replacement against", + "bbox": [ + 496, + 750, + 890, + 900 + ], + "page_idx": 1 + }, + { + "type": "page_number", + "text": "23031", + "bbox": [ + 478, + 945, + 517, + 955 + ], + "page_idx": 1 + }, + { + "type": "text", + "text": "track-based approaches, owning largely improved robustness. With respect to the motion representation, homography mixture [4], mesh [25, 22, 34], and optical flow [26, 20] based motion models are proposed to deal with scenes that contain large depth variations. Besides, some approaches focus on special stabilization tasks, such as Selfie [42], 360 [15], and hyperlapse videos [13].", + "bbox": [ + 75, + 90, + 467, + 196 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "On the other hand, 3D-based methods require 3D camera motions or scene structure for stabilization. The 3D structure can either be calculated from the video by structure-from-motion (SfM) [18] or acquired from additional hardware, such as a depth camera [23], a gyroscope sensor [14], or a light field camera [32]. However, full 3D stabilization is fragile and computationally expensive [18]. Partial 3D methods proposed 3D constraints, such as subspace projection [19] and epipolar geometry [3], to alleviate the requirement of full 3D reconstruction [7]. Normally, 3D methods can better handle the scene parallax compared with 2D approaches due to the physical correctness, as long as the 3D information can be available.", + "bbox": [ + 75, + 198, + 467, + 393 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.2. Deep Learning Methods", + "text_level": 1, + "bbox": [ + 76, + 404, + 299, + 420 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Deep methods take the video frames as input and directly output the stabilized frames, which are often trained with stable and unstable frame pairs acquired by special hardware, e.g., DeepStab dataset [33]. Xu et al. used the adversarial network to generate a target image to guide the warping [35]. Yu et al. learned the flow fields from initial optical flow estimation for the accurate per-pixel motion compensation [41]. Deep methods suffer from the generalization problem, given that DeepStab only contains 60 videos. Yu et al. used the CNN as the optimizer instead of learning from data to overfit each input example [40].", + "bbox": [ + 75, + 428, + 467, + 594 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Recently, deep motion models have achieved good results for motion estimation, such as deep homography [38, 8] and deep meshflow [39], which is more robust in adverse cases compared to traditional solutions, such as scenes of low texture and low light. In this work, we adopt the deep meshflow [39] for our camera motion estimator and design a network concentrating on camera path smoothing.", + "bbox": [ + 75, + 595, + 467, + 700 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "2.3. Online Approaches", + "text_level": 1, + "bbox": [ + 76, + 710, + 261, + 727 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Most of the video stabilization approaches are offline, where a video is processed after it has been captured. Online methods stabilize a video during the capture [37, 33, 22]. One may argue that global path optimization can be easily modified to online methods by applying a sliding window scheme. However, the stability would inevitably decrease, let alone the existence of challenging camera motions, such as quick rotation and zooming, which may introduce artifacts such as wobble and excessive cropping. Previously, these difficult motions can only be solved satisfactorily by global camera path smoothing. In this work,", + "bbox": [ + 75, + 734, + 467, + 900 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "we propose to solve these problems with our proposed deep online camera path optimization framework.", + "bbox": [ + 498, + 90, + 890, + 121 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3. Methodology", + "text_level": 1, + "bbox": [ + 500, + 133, + 633, + 152 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.1. Problem Formulation", + "text_level": 1, + "bbox": [ + 500, + 159, + 700, + 174 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Our method is built upon convolutional neural networks. As illustrated in Fig. 3 (a), given an incoming unsteady frame $I_{t}$ at timestamp $t$ , our deep online video stabilization aims to predict the corresponding steady frame $I_{t}^{\\prime}$ with no future frames. Here, we use “/” to represent predicted quantities. Note that, previous learning-based methods learn the mapping $f(\\cdot)$ from the input shaky RGB frames and predict a warp field $B_{t}^{\\prime}$ of frame $I_{t}$ , which can be formulated as", + "bbox": [ + 498, + 181, + 890, + 303 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\left\\{B _ {t} ^ {\\prime} \\right\\} = f \\left(\\left\\{I _ {t} \\right\\}\\right), \\tag {1}\n$$\n", + "text_format": "latex", + "bbox": [ + 633, + 315, + 890, + 333 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\{\\cdot\\}$ represents a set of elements. However, our experiments show that directly using complex RGB video frames as input and mixing motion estimation and path smoothing in a network frequently causes estimation errors, resulting in wobbling and distortion artifacts.", + "bbox": [ + 496, + 343, + 890, + 419 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "In this work, we propose our approach from a novel perspective, where we separate the motion estimation step from the network alone and leave the network focus on camera path smoothing. Specifically, we consider using a fixed window of $r$ past frames $\\{I_t\\}_r = \\langle I_{t - r},\\dots,I_{t - 1},I_t\\rangle$ of minimum latency (i.e. without using future frames) to stabilize the incoming target frame $I_{t}$ . The camera motion $\\{F_t\\}$ is estimated by an off-the-shelf deep motion estimation model. Our camera path smooth network uses only the estimated motion as input to predict the corresponding warp field $B_t'$ , i.e.,", + "bbox": [ + 498, + 420, + 890, + 585 + ], + "page_idx": 2 + }, + { + "type": "equation", + "text": "\n$$\n\\left\\{B _ {t} ^ {\\prime} \\right\\} = \\Phi \\left(\\left\\{F _ {t} \\right\\}; \\theta\\right), \\tag {2}\n$$\n", + "text_format": "latex", + "bbox": [ + 625, + 595, + 890, + 616 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "where $\\Phi(\\cdot)$ denotes the camera path smoothing network and $\\theta$ is the network parameters to be optimized. We empirically set $r$ to 15 in our experiments.", + "bbox": [ + 498, + 626, + 890, + 672 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "3.2. Deep Online Camera Path Optimization", + "text_level": 1, + "bbox": [ + 500, + 681, + 843, + 698 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "As shown in Fig. 2, the overall pipeline of the proposed deep online camera path optimization framework mainly consists of three stages. Firstly, we adopt a deep motion extraction model for robust camera motion estimation. Secondly, the camera path smooth network takes the unsteady camera motion as input and predicts the smoothed warp field. Finally, the original shaky frame is transformed by the predicted warp field to synthesize the target steady frame.", + "bbox": [ + 496, + 704, + 890, + 825 + ], + "page_idx": 2 + }, + { + "type": "text", + "text": "Camera Motion Estimation The first step is to estimate the camera motion. We employ an optimized deep mesh-flow model [39] to extract the inter-frame motion. Specifically, given the incoming frame $I_{t}$ and past adjacent frame", + "bbox": [ + 496, + 839, + 890, + 900 + ], + "page_idx": 2 + }, + { + "type": "page_number", + "text": "23032", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 2 + }, + { + "type": "image", + "img_path": "images/bc01b6585b98bd47570dab0021445423a4c5d6485ca18a1476aee7a6f2f5b394.jpg", + "image_caption": [ + "Figure 2. The overall pipeline of the proposed deep online camera path optimization framework. (a) We first employ a deep motion extraction model to estimate the unsteady camera motion. (b) Then, the estimated motion is fed into the camera path smooth network, yielding the smoothed warp field. (c) Finally, the target steady frame is synthesized by the predicted smooth warp field." + ], + "image_footnote": [], + "bbox": [ + 102, + 88, + 869, + 327 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/e154d9df9a963fc93899e9f318b36fb40dcb138ce76f8fb5f182457357377c1e.jpg", + "image_caption": [ + "(a)" + ], + "image_footnote": [], + "bbox": [ + 81, + 398, + 256, + 492 + ], + "page_idx": 3 + }, + { + "type": "image", + "img_path": "images/993bf0d2ef9444d76e7503ff2ec5b357403a89a63584c45007cf0123625be8a5.jpg", + "image_caption": [ + "(b)", + "Figure 3. Relationships between the unstable/synthesized video and the stable video. (a) depicts the basic relationships of the unstable video $\\{I_t\\}$ and stabilized video $\\{I_t'\\}$ , and (b) illustrates the main idea of our dataset synthesis strategy that transfers collected unstable motions $\\{F_t^{\\mathrm{ust}}\\}$ to stable video frames $\\{I_t^{\\mathrm{stb}}\\}$ , generating synthesized unstable video frames $\\{I_t^{\\mathrm{syn}}\\}$ ." + ], + "image_footnote": [], + "bbox": [ + 287, + 398, + 460, + 492 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "$I_{t - 1}$ with size of $640\\times 360$ we estimate $F_{t}$ by model [39] (Fig. 3 (a), upper yellow part). Repeat this process, we accumulate a set of inter-frame motions, $\\{F_t\\}_{r - 1} = \\langle F_{t - r + 1},\\dots ,F_{t - 1},F_t\\rangle$ . In particular, we keep the most recent $r - 1$ motions in our buffer, where historical motions that are beyond range $r - 1$ are simply dropped. The deep meshflow motion estimation is defined as:", + "bbox": [ + 76, + 622, + 468, + 728 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nF _ {t} = \\downarrow_ {s} \\mathcal {M} _ {F} \\left(I _ {t}, I _ {t - 1}\\right), \\tag {3}\n$$\n", + "text_format": "latex", + "bbox": [ + 194, + 738, + 468, + 755 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathcal{M}_F(\\cdot)$ is the pre-trained deep meshflow model. $\\downarrow_{s}$ indicates that we collect the sparse motions at the mesh vertexes, and shrink them pixel by pixel to form a downsampled dense motion field, for the purpose of feeding it to the CNNs. The scale factor $s$ is set to 8, and the size of the dense motion field $F_{t}$ is $80\\times 45$ .", + "bbox": [ + 75, + 763, + 468, + 854 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Camera Path Smooth Network Given the estimated camera motion $\\{F_t\\}_{r - 1}$ as input, the camera path smooth net", + "bbox": [ + 75, + 869, + 468, + 902 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "work predicts the target smoothed warp field $B_{t}^{\\prime}$ as Eq. 2. Note that, the meshflow model is spatially-variant, and so does the $F_{t}$ . Therefore, we provide spatial and temporal optimizations. The camera path smooth network is designed as an encoder-decoder architecture and we implement it as a 4-stage UNet with channels of 64, 128, 256, and 512. We further employ the channel attention mechanism (CA) [9] to adaptively learn the weights of different historical motions.", + "bbox": [ + 496, + 398, + 890, + 521 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Steady Frame Rendering After obtaining the warp field $B_{t}^{\\prime}$ , we inverse the process of shrinking, where we put the motions back to the sparse vertex locations to create a mesh, based on which we warp the shaky frame $I_{t}$ to its stabilized position $I_{t}^{\\prime}$ :", + "bbox": [ + 496, + 536, + 890, + 612 + ], + "page_idx": 3 + }, + { + "type": "equation", + "text": "\n$$\nI _ {t} ^ {\\prime} = \\mathcal {W} \\left(I _ {t}, B _ {t} ^ {\\prime}\\right), \\tag {4}\n$$\n", + "text_format": "latex", + "bbox": [ + 638, + 625, + 890, + 643 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "where $\\mathcal{W}(\\cdot)$ denotes the backward warping function. The first parameter is an image and the second is a warp field.", + "bbox": [ + 496, + 654, + 890, + 686 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "3.3. Training Dataset", + "text_level": 1, + "bbox": [ + 500, + 695, + 666, + 710 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Existing training datasets are either captured simultaneously by two cameras [33] or synthesized by simulated injected noise [10, 29, 11]. The former would naturally suffer from parallax problems, while the latter makes the synthesized video paths unrealistic. To address this issue, we offer a novel synthetic method that can build realistic unstable/stable motion pairs from existing shaky videos.", + "bbox": [ + 496, + 719, + 890, + 824 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "Our main idea is to transfer the motion of an unstable shaky video $V_{\\mathrm{ust}}$ to a stable video $V_{\\mathrm{stb}}$ , yielding another synthesized shaky video $V_{\\mathrm{syn}}$ with motions from $V_{\\mathrm{ust}}$ but image contents as $V_{\\mathrm{stb}}$ . The videos $V_{\\mathrm{ust}}$ and $V_{\\mathrm{stb}}$ are irrelevant. Let's denote $\\{I_t^{\\mathrm{ust}}\\}$ , $\\{I_t^{\\mathrm{stb}}\\}$ , $\\{I_t^{\\mathrm{syn}}\\}$ as video frames and", + "bbox": [ + 496, + 825, + 893, + 902 + ], + "page_idx": 3 + }, + { + "type": "page_number", + "text": "23033", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 3 + }, + { + "type": "text", + "text": "$\\{F_t^{\\mathrm{ust}}\\} ,\\{F_t^{\\mathrm{stb}}\\} ,\\{F_t^{\\mathrm{syn}}\\}$ as motion between frames of video $\\mathbf{V}_{\\mathrm{ust}},\\mathbf{V}_{\\mathrm{stb}},\\mathbf{V}_{\\mathrm{syn}}$ accordingly.", + "bbox": [ + 76, + 89, + 467, + 121 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To achieve this, we first estimate the motions $\\{F_t^{\\mathrm{ust}}\\}$ , $\\{F_t^{\\mathrm{stb}}\\}$ between adjacent frames of $V_{\\mathrm{ust}}$ and $V_{\\mathrm{stb}}$ by deep meshflow [39]. Next, we warp the frame $\\{I_t^{\\mathrm{stb}}\\}$ by motion $\\{F_t^{\\mathrm{ust}}\\}$ to produce $\\{I_t^{\\mathrm{syn}}\\}$ , for each timestamp $t$ :", + "bbox": [ + 76, + 121, + 467, + 183 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nI _ {t} ^ {\\text {s y n}} = \\mathcal {W} \\left(I _ {t} ^ {\\text {s t b}}, F _ {t} ^ {\\text {u s t}}\\right). \\tag {5}\n$$\n", + "text_format": "latex", + "bbox": [ + 200, + 188, + 467, + 205 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Applying Eq. 5 to every frame of $V_{\\mathrm{stb}}$ creates the desired $V_{\\mathrm{syn}}$ . The $V_{\\mathrm{stb}}$ and $V_{\\mathrm{syn}}$ become a pair of stable/unstable videos, where the following motion equality holds (Please refer to Fig. 3 (b) for the relation), for each timestamp $t$ :", + "bbox": [ + 76, + 213, + 467, + 273 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nF _ {t} ^ {\\text {u s t}} + F _ {t} ^ {\\text {s y n}} = F _ {t} ^ {\\text {s t b}} + F _ {t - 1} ^ {\\text {u s t}}, \\tag {6}\n$$\n", + "text_format": "latex", + "bbox": [ + 179, + 294, + 467, + 311 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $F_{t}^{\\mathrm{ust}}$ , $F_{t}^{\\mathrm{stb}}$ have been calculated which are known. Therefore, $F_{t}^{\\mathrm{syn}}$ can be calculated as:", + "bbox": [ + 76, + 320, + 467, + 351 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\nF _ {t} ^ {\\text {s y n}} = F _ {t} ^ {\\text {s t b}} + F _ {t - 1} ^ {\\text {u s t}} - F _ {t} ^ {\\text {u s t}}. \\tag {7}\n$$\n", + "text_format": "latex", + "bbox": [ + 179, + 357, + 467, + 375 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "During the training, our network takes a subset of motions $\\{F_t^{\\mathrm{syn}}\\}_{r - 1} = \\langle F_{t - r + 1}^{\\mathrm{syn}},\\dots ,F_{t - 1}^{\\mathrm{syn}},F_t^{\\mathrm{syn}}\\rangle$ as input and output a motion field that is as close as the ground-truth label $-F_{t}^{\\mathrm{ust}}$ , which is the inverse motion of $F_{t}^{\\mathrm{ust}}$ as shown in Fig. 3 (b). On the other hand, the generated videos $V_{\\mathrm{stb}}$ and $V_{\\mathrm{syn}}$ are not important, as all we need are motions that can be calculated and derived by relations.", + "bbox": [ + 76, + 382, + 467, + 487 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To further establish the training dataset, we collected 110 stable videos of five categories (including regular, rotation, zooming, parallax, and crowd) using a cell phone mounted on a hand-held physical stabilizer. Next, we collected over 150 unstable videos from the website. Subsequently, we performed data synthesis on the collected stable and unstable videos by employing the aforementioned method, constructing the MotionStab dataset, which contains paired unstable/stable camera motion of various complex scenarios. As illustrated in Fig. 1 (b), the camera path of the synthesized video pairs is well-registered and realistic as the original unstable one.", + "bbox": [ + 75, + 488, + 467, + 667 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "3.4. Training Loss", + "text_level": 1, + "bbox": [ + 76, + 676, + 218, + 691 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "To train the camera path smooth network, we define several losses in our framework: the motion-consistency loss for maintaining motion continuity between consecutive frames, the shape-consistency loss for preserving the geometry of the predicted warp field, and the scale-preserving loss for maintaining the scale of the predicted warp field.", + "bbox": [ + 75, + 700, + 467, + 789 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Motion-consistency Loss To keep the continuity of the predicted consecutive video frames, the inter-frame motion of the stabilized video $F_{t}^{\\prime}$ should be as similar as the ground truth one $\\hat{F}_{t}$ , i.e.,", + "bbox": [ + 75, + 805, + 467, + 864 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {M C}} = \\left\\| F _ {t} ^ {\\prime} - \\hat {F} _ {t} \\right\\| _ {1}. \\tag {8}\n$$\n", + "text_format": "latex", + "bbox": [ + 200, + 869, + 467, + 897 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/ccab14db126c57c99f19b50482e43e9ef3f584284a2bcb2dd441266bdb5645c7.jpg", + "image_caption": [ + "(a) original meshgrid" + ], + "image_footnote": [], + "bbox": [ + 517, + 90, + 656, + 193 + ], + "page_idx": 4 + }, + { + "type": "image", + "img_path": "images/0dacd8306a21dc7955c540c2d9e5ce04a38030ed242a14520c6b1128ef5d50dd.jpg", + "image_caption": [ + "(b) transformed meshgrid", + "Figure 4. Illustration of the shape-consistency loss and the scale-preserving loss. The shape-consistency loss is employed to preserve the geometry shape of a meshgrid and the scale-preserving loss is used to maintain the scale." + ], + "image_footnote": [], + "bbox": [ + 720, + 90, + 861, + 193 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "According to the relationship of Fig. 3 (a), Eq. 8 can be written as", + "bbox": [ + 500, + 292, + 890, + 321 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\begin{array}{l} \\mathcal {L} _ {\\mathrm {M C}} = \\left\\| \\left(F _ {t} + B _ {t - 1} ^ {\\prime} - B _ {t} ^ {\\prime}\\right) - \\left(F _ {t} + \\hat {B} _ {t - 1} - \\hat {B} _ {t}\\right) \\right\\| _ {1} (9) \\\\ = \\left\\| B _ {t - 1} ^ {\\prime} - B _ {t} ^ {\\prime} - \\hat {B} _ {t - 1} + \\hat {B} _ {t} \\right\\| _ {1}, (10) \\\\ \\end{array}\n$$\n", + "text_format": "latex", + "bbox": [ + 513, + 329, + 890, + 385 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $B_{t}^{\\prime}$ denotes network output of the predicted warp field. That is to say, the motion continuity can be restrained by the ground truth warp field $\\hat{B}_{t}$ and $\\hat{B}_{t - 1}$ .", + "bbox": [ + 498, + 397, + 890, + 443 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Shape-consistency Loss The shape-consistency loss is effective to prevent the distortion problem of the predicted warp field. Following Wang et al. [33], we implement the SC loss as an intra-grid loss term and an inter-grid loss term:", + "bbox": [ + 498, + 458, + 890, + 518 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {S C}} = \\mathcal {L} _ {\\text {i n t r a}} + \\mathcal {L} _ {\\text {i n t e r}}. \\tag {11}\n$$\n", + "text_format": "latex", + "bbox": [ + 624, + 545, + 890, + 560 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Note that each pixel of our dense warp field is actually a vertex of the mesh grid. As depicted in Fig. 4, the intra-grid loss term is defined as:", + "bbox": [ + 498, + 571, + 890, + 616 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {i n t r a}} = \\frac {1}{N} \\sum_ {v _ {i}} \\left\\| \\left(v _ {i} ^ {1} - v _ {i}\\right) \\cdot \\left(v _ {i} ^ {2} - v _ {i}\\right) \\right\\| _ {1}, \\tag {12}\n$$\n", + "text_format": "latex", + "bbox": [ + 557, + 625, + 890, + 661 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "where $i$ denotes the $i$ -th vertex and $N$ is the total number of vertices. Besides, the inter-grid loss term is used to maintain the geometric consistency of adjacent grids:", + "bbox": [ + 498, + 671, + 890, + 715 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\text {i n t e r}} = \\frac {1}{N} \\sum_ {v _ {i}} \\left\\| \\left(v _ {i} ^ {1} - v _ {i}\\right) - \\left(v _ {i} - v _ {i} ^ {3}\\right) \\right\\| _ {1}. \\tag {13}\n$$\n", + "text_format": "latex", + "bbox": [ + 539, + 726, + 890, + 762 + ], + "page_idx": 4 + }, + { + "type": "text", + "text": "Scale-preserving Loss Since we convert the sparse motions at the mesh vertexes as a dense motion field and predict the mesh warp field, we introduce a scale-preserving loss to maintain the scale consistency of the predicted warp field:", + "bbox": [ + 498, + 772, + 890, + 833 + ], + "page_idx": 4 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} _ {\\mathrm {S P}} = \\frac {1}{N} \\sum_ {v _ {i}} \\left\\| \\frac {\\left\\| v _ {i} ^ {1} - v _ {i} \\right\\| _ {2}}{s} - 1 \\right\\| _ {1}. \\tag {14}\n$$\n", + "text_format": "latex", + "bbox": [ + 575, + 854, + 890, + 897 + ], + "page_idx": 4 + }, + { + "type": "page_number", + "text": "23034", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 4 + }, + { + "type": "table", + "img_path": "images/d98bda1901f3c835371268bfc98eb183cb3f208ab5d3aa6e70e4733d7c22f987.jpg", + "table_caption": [ + "Table 1. Quantitative comparisons on the NUS dataset [25]. We use the Cropping ratio (C), the Distortion value (D), and the Stability score (S) as evaluation metrics. All of these metrics are in the range of 0 to 1, and the higher the better. The $*$ denotes the results of Bundled [25] are computed directly from the NUS dataset. The bests are marked in red and the second bests are in blue." + ], + "table_footnote": [], + "table_body": "
MethodsRegularRotationZooming
CDSCDSCDS
Offline* Bundled [25]0.66580.94090.90480.64770.86920.91940.57730.90730.9236
Robust L1 [5]0.71570.92520.84540.72060.82310.86170.71070.83290.7730
DIFRINT [1]0.98540.95550.81770.94130.88130.87010.95280.85310.8763
Yu et al. [41]0.94860.97520.84270.76610.76160.93170.89710.86300.9107
PWStableNet [43]0.93190.98520.81620.88010.97070.92510.93030.97920.8906
DUT [36]0.94850.96000.87170.76090.69400.92030.89860.86060.9221
OnlineMeshflow [22]0.80810.91680.83860.75780.76790.90920.77730.87150.8839
StabNet [33]0.74910.83930.84060.74170.72050.83840.73760.78070.8697
Ours0.94330.99170.80300.90210.98470.93410.91850.97360.8982
MethodsCrowdParallaxAvg.
CDSCDSCDS
Offline* Bundled [25]0.66850.89100.87440.71580.89650.89640.65500.90100.9037
Robust L1 [5]0.72080.90770.85040.71320.80540.87780.71620.85890.8417
DIFRINT [1]0.96620.87130.84560.97460.88230.86000.96410.88870.8539
Yu et al. [41]0.90810.91910.86600.92090.92190.88960.88820.88720.8881
PWStableNet [43]0.91810.97900.81620.92440.98020.85490.91700.97890.8606
DUT [36]0.89860.86170.90420.92540.87740.91270.88600.85070.9062
OnlineMeshflow [22]0.78880.82460.82800.81210.84290.84880.78820.87620.8617
StabNet [33]0.72470.77250.79120.69670.76600.82890.72800.77580.8338
Ours0.92470.98160.84080.93260.98270.87620.92420.98290.8705
", + "bbox": [ + 99, + 128, + 874, + 457 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $s$ is the scale factor in Eq. 3. Eventually, the overall loss is the combination of the above three loss terms:", + "bbox": [ + 76, + 474, + 468, + 505 + ], + "page_idx": 5 + }, + { + "type": "equation", + "text": "\n$$\n\\mathcal {L} = \\mathcal {L} _ {\\mathrm {M C}} + \\alpha \\mathcal {L} _ {\\mathrm {S C}} + \\beta \\mathcal {L} _ {\\mathrm {S P}}, \\tag {15}\n$$\n", + "text_format": "latex", + "bbox": [ + 179, + 518, + 468, + 536 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "where $\\alpha$ and $\\beta$ are empirically set to 0.01.", + "bbox": [ + 76, + 547, + 356, + 564 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4. Experimental Results", + "text_level": 1, + "bbox": [ + 76, + 578, + 282, + 595 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.1. Implementation Details", + "text_level": 1, + "bbox": [ + 76, + 604, + 294, + 619 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Evaluation Metrics For quantitative comparison, we employ three widely used metrics: cropping ratio, distortion value, and stability score, as in prior methods [25, 36, 43, 22]. For cropping ratio and distortion value, we first fit a global homography between the input and output videos at each frame. The cropping ratio measures the remaining frame area after cropping out undefined pixels due to motion compensation and is computed as the average scale component of the entire video. The distortion value, which is defined as the worst ratio of the two largest eigenvalues of the affine component across all frames, measures the anisotropic scaling of the homography between the input and output frames. The stability score measures the smoothness of the stabilized videos and the camera path is utilized to determine the value. We compute this metric by using a frequency domain analysis as in Bundled [25].", + "bbox": [ + 75, + 628, + 468, + 869 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Implementation Details Our network is implemented by PyTorch. We use Adam as the optimizer for training, with", + "bbox": [ + 76, + 869, + 468, + 901 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "an initial learning rate of $1 \\times 10^{-4}$ and no weight decay. We set $\\beta_{1} = 0.9$ , $\\beta_{2} = 0.999$ , and $\\epsilon = 1e - 8$ , respectively. We train the network for 100,000 iterations. The overall training time on two NVIDIA 1080Ti GPUs is 20 hours. During training, two adjacent frames and their corresponding historical frames are selected as a training sample. The MotionStab dataset comprises 65238 training samples in total. For inference, the overall framework can process a frame of size $640 \\times 360$ in real-time. Specifically, we spend 12 ms, 10 ms, and 4 ms to extract camera motion, smooth the camera path, and synthesize stable frames, respectively.", + "bbox": [ + 496, + 474, + 890, + 642 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "4.2. Comparisons with Existing Methods", + "text_level": 1, + "bbox": [ + 498, + 650, + 815, + 667 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "To evaluate the proposed approach, we compare it with the state-of-the-art methods on the NUS dataset [25]. The compared methods include three traditional methods, Bundled [25], Robust L1 [5], Meshflow [22], and five deep learning based methods, DIFRINT [1], Yu et al. [41], PW-StableNet [43], DUT [36], and StabNet [33]. It is worth noting that Meshflow [22], StabNet [33], and ours are online, while the rest are offline. The results of the compared methods are obtained from publicly accessible implementations with default parameters or pre-trained models.", + "bbox": [ + 496, + 674, + 890, + 824 + ], + "page_idx": 5 + }, + { + "type": "text", + "text": "Quantitative results Table 1 presents the quantitative results for each of the five categories (including regular, quick rotation, zooming, crowd, and parallax), as well as the average results across all categories. From Table 1, we can see that offline approaches generally outperform online meth", + "bbox": [ + 496, + 825, + 890, + 900 + ], + "page_idx": 5 + }, + { + "type": "page_number", + "text": "23035", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 5 + }, + { + "type": "image", + "img_path": "images/fad4366167722f0e8f00d9253a521d394314aea67e7394b4858186ae480c2f68.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 102, + 95, + 303, + 176 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/c50730e5163c7c1520d8fc74f897a652a4ec789c8c85f98aa083bc071fd6685b.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 305, + 95, + 491, + 176 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/65109fb838b10a7059575f7946138f2ee89ed90f9da2a7c1b7df202f8c969fa7.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 491, + 95, + 674, + 176 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/83829c3750c8914f90888cff1ed01f6591cff5bc04fec59cd77ca8aa75d8d0b8.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 676, + 95, + 861, + 176 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/88366a8ba0d4a1fcdc386cbf272d4c9c3615ffca85918ff2c5942cc8567479ba.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 102, + 176, + 303, + 257 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/60e0a64589b2eecc0990ab4c5269fdf7e5ee9c45b0ae2285f02f6e5b459c924d.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 305, + 176, + 491, + 257 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/381a2f9486c27f07b408aa52e35e3097591a179010208114301836f30cf987b7.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 491, + 176, + 674, + 257 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/13fdd79c1779275bf3eb9c30417051cce3f030c050d0a85d99635cc557a46453.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 676, + 176, + 862, + 257 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/04d95e27f195da35672408352acd26f2a5ff8f7ae3d9f38ec616f6fb7966f865.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 102, + 258, + 303, + 338 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/b2d602d1818445c7171527dba5e05949126fa2b39b26ba4e222dcfd75b878e51.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 305, + 258, + 491, + 338 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/7a0995bf53464e9d7c6477dd64210c4a8980e44d0ace36d90a93fc75c407b022.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 491, + 258, + 674, + 338 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/e8226e73869bcad9521925ec46839eb6ee938297c8972d1ddaaeb83828277e1e.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 676, + 258, + 862, + 338 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/0da421cc20ae680eeb209c987b9364764d143e1f917f3498a57ca5ee4b6a66ae.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 102, + 339, + 303, + 417 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1a39b4bc518ba7ce74fbbb8fb127294549ca1c481a9f5e9201eb507fb8d25604.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 305, + 339, + 491, + 417 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/ec85eca88e1dfae25eb0b7e6d51c2c8f77d75d56a92d14b2bda9557695c17d7a.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 491, + 339, + 674, + 417 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/6cb21691cba3f3da6b28b36d2def4409c062445a1558cfbdba448830a30b42d5.jpg", + "image_caption": [], + "image_footnote": [], + "bbox": [ + 676, + 339, + 862, + 417 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/2e2f40175cc13592998b75a7c912b80d99709fb4a8d7ed8b2800a78fa272b88d.jpg", + "image_caption": [ + "(a) Meshflow" + ], + "image_footnote": [], + "bbox": [ + 102, + 419, + 303, + 500 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/62a38c98c8b31ae2d7043e5a9456a8dc24d7ed70cc9215cad9e6782595eba3d8.jpg", + "image_caption": [ + "(b) StabNet" + ], + "image_footnote": [], + "bbox": [ + 305, + 420, + 491, + 500 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/5a91124dfbf4cb9f96ae0b55bd2ad6bd6ac6adea671ba7c97b1c4ec461a46b04.jpg", + "image_caption": [ + "(c) Ours", + "Figure 5. Qualitative comparisons with the online methods Meshflow [22] and StabNet [33]. We keep the original warped frames for comparison. The red boxes indicate the preserved frame content after cropping. The red arrows highlight the shear and distortion artifacts." + ], + "image_footnote": [], + "bbox": [ + 491, + 419, + 674, + 500 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/1b834a7bb0f6e499f22a814e7c9b42ba64e79d41ef64643fe561b73a000b41a3.jpg", + "image_caption": [ + "(d) Input frame" + ], + "image_footnote": [], + "bbox": [ + 676, + 420, + 862, + 500 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "ods, especially in challenging scenarios. In comparison to existing online approaches, our method achieves significant performance improvements. Taking Meshflow [22] as the baseline, the cropping ratio and the distortion value of our method increase by $17.25\\%$ and $12.18\\%$ , respectively. Notably, our method can achieve approaching results to several compared offline methods.", + "bbox": [ + 75, + 573, + 468, + 679 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Qualitative results Fig. 5 illustrates the flaws that can be noticed directly from the video frames, including shear, distortion, and over-cropping. As can be seen, Meshflow suffers from shear and distortion in some scenes due to its reliance on well-optimized parameter tweaking. The shear and over-cropping problems in StabNet [33] are more severe because they directly employ video frames as input for mixed camera motion estimation and path smoothing, making the performance and generalization ability difficult to even approach the traditional approach Meshflow [22]. On the contrary, since our network solely smooths and optimizes the camera path, regardless of image content, it is more generic on diverse challenging scenes and can avoid the aforementioned issues in an online setting.", + "bbox": [ + 75, + 689, + 470, + 900 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "User Study We also conduct a user study comparing our method to the PWStableNet [43], which is one of the deep offline approaches that achieves overall good performances according to Table 1. Note that we do not compare with the online methods [22, 33], because our qualitative results are significantly better than theirs. Specifically, we prepare a test set containing 15 videos (3 videos per category), and each of the 20 participants is asked to choose the better one from the results of the two compared methods. The videos are arranged randomly and the original unstable videos are provided. The results of the user study are shown in Fig. 7.", + "bbox": [ + 496, + 573, + 890, + 739 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "4.3. Ablation Studies", + "text_level": 1, + "bbox": [ + 500, + 753, + 663, + 768 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "To analyze the capability of each component, we conduct extensive ablation experiments on the NUS dataset [25].", + "bbox": [ + 496, + 777, + 890, + 808 + ], + "page_idx": 6 + }, + { + "type": "text", + "text": "Ablation on losses We first conduct experiments on the motion-consistency loss, the shape-consistency loss, and the scale-preserving loss. In the first row of Table 2, we take the vanilla UNet optimized by the MC loss as our baseline. In the next two rows, we add the SC loss and the SP loss to train the model, respectively. Comparing the first three rows", + "bbox": [ + 496, + 810, + 890, + 900 + ], + "page_idx": 6 + }, + { + "type": "page_number", + "text": "23036", + "bbox": [ + 478, + 945, + 517, + 955 + ], + "page_idx": 6 + }, + { + "type": "image", + "img_path": "images/64c8afe9dfbadb16b77839161c267065890a0ec5e1163b5c8c2a9ec7b805aa12.jpg", + "image_caption": [ + "(a) MC" + ], + "image_footnote": [], + "bbox": [ + 102, + 93, + 303, + 258 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/25102eeddcf1ff26280e87205d00fb675e5528acbbb93ea64ea09470bc0c3bac.jpg", + "image_caption": [ + "(b) $\\mathrm{MC} + \\mathrm{SC}$" + ], + "image_footnote": [], + "bbox": [ + 305, + 93, + 488, + 258 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/a8deaeadd0f4f7c601d6edcd408e6d63c0ae2094ca4d0a5c5a8debbe6ffdac98.jpg", + "image_caption": [ + "(c) $\\mathrm{MC} + \\mathrm{SC} + \\mathrm{SP}$" + ], + "image_footnote": [], + "bbox": [ + 491, + 93, + 678, + 258 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/2c0799781a198c07c416afed5c74872644e487e34f85418f3219b75a01465e3a.jpg", + "image_caption": [ + "(d) Input frame" + ], + "image_footnote": [], + "bbox": [ + 679, + 94, + 866, + 258 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/f905e1e70b7356d73df1c698ae13b2ab887c57408811907bcac6877bc2917db8.jpg", + "image_caption": [ + "Figure 6. Qualitative results of the ablation study on the motion-consistency loss (MC), the shape-consistency loss (SC), and the scale-preserving loss (SP). The red arrows show the shear and distortion regions, and the red boxes show the preserved frame region.", + "Figure 7. User study results comparing with PWStableNet [43]." + ], + "image_footnote": [], + "bbox": [ + 84, + 316, + 460, + 421 + ], + "page_idx": 7 + }, + { + "type": "table", + "img_path": "images/0455e5ecfc083999dae0b47a303329e0c6be62f821c7f8faf0f6bfd55f3bd4bf.jpg", + "table_caption": [ + "Table 2. Quantitative results of the ablation studies on the hybrid loss and the channel attention mechanism (CA)." + ], + "table_footnote": [], + "table_body": "
MCSCSPCACDS
Baseline✓0.800.840.87
Variant 1✓✓0.850.900.86
Variant 2✓✓✓0.900.950.86
Ours✓✓✓✓0.920.980.87
", + "bbox": [ + 88, + 482, + 457, + 555 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "reveals that adding the SC loss and the SP loss respectively improves performance. The best performance is gained by combining them together. Fig. 6 shows some qualitative results. As seen, when only using the MC loss, substantial shear, and distortion occur (Fig. 6 (a), highlighted by red arrows.). The distortion artifacts can be effectively resolved by adding the SC loss (Fig. 6 (b)). However, the scale of the stabilized frame is not well preserved, resulting in larger cropped regions. This issue can eventually be solved by the proposed SP loss (Fig. 6 (c), distinguished by red boxes).", + "bbox": [ + 75, + 580, + 467, + 733 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Analysis of the quality of the dataset To verify the impact of the dataset, we train the network on the DeepStab [33] and our MotionStab dataset, respectively. Fig. 8 shows the quantitative results on the NUS dataset. As seen, when trained using the proposed MotionStab dataset, both our method and StabNet [33] yield better results than training on the DeepStab dataset, respectively, especially in terms of cropping ratio and distortion value. We conclude that the main reasons are twofold. Firstly, our MotionStab dataset contains richer scenarios and unstable motions, improving the performance and generalization ability of the network.", + "bbox": [ + 75, + 734, + 467, + 900 + ], + "page_idx": 7 + }, + { + "type": "image", + "img_path": "images/56e589c53c1accd1e779900014fb03270eda1dd2feec49c09638bd37909f7d9d.jpg", + "image_caption": [ + "Figure 8. Comparisons of the quantitative results between StabNet [33] and our method when trained with different datasets." + ], + "image_footnote": [], + "bbox": [ + 519, + 316, + 874, + 463 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Secondly, the synthesized pairs in MotionStab suffer no parallax issue inherent in DeepStab, leading to fewer distortion artifacts (i.e., higher distortion value) in the stabilized frames. Additionally, our method outperforms StabNet [33] on both datasets, demonstrating its superiority over directly predicting stable warp fields from input video frames.", + "bbox": [ + 498, + 510, + 890, + 602 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "5. Conclusions", + "text_level": 1, + "bbox": [ + 500, + 616, + 625, + 632 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "This work presents a deep camera path optimization framework for online video stabilization. We leave the motion estimation to recent off-the-shelf deep motion models and concentrate on path smoothing. Our model takes a 2D camera path in a sliding window as input and outputs a warp field for the last frame in that window. A video can be stabilized online by applying our model repeatedly for every incoming frame. We introduce a hybrid loss to enhance the spatial and temporal consistency of the stabilized video. Moreover, we created a motion dataset to train our model. Results show that our method outperforms previous approaches both qualitatively and quantitatively.", + "bbox": [ + 496, + 642, + 890, + 824 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "Acknowledgements This work was supported by Sichuan Science and Technology Program of China under grants Nos. 2023NSFSC0462, 2023NSFSC1972, 2022YFQ0079, 2021YFG0001, 2022YFG0050, and National Natural Science Foundation of China under grant No.62031009.", + "bbox": [ + 496, + 825, + 890, + 900 + ], + "page_idx": 7 + }, + { + "type": "page_number", + "text": "23037", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 7 + }, + { + "type": "text", + "text": "References", + "text_level": 1, + "bbox": [ + 78, + 89, + 174, + 106 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[1] Jinsoo Choi and In So Kweon. Deep iterative frame interpolation for full-frame video stabilization. ACM Trans. on Graphics (TOG), 39(1):1-9, 2020. 6", + "[2] Michael L Gleicher and Feng Liu. Re-cinematography: Improving the camerawork of casual video. ACM transactions on multimedia computing, communications, and applications (TOMM), 5(1):1-28, 2008. 2", + "[3] Amit Goldstein and Raanan Fattal. Video stabilization using epipolar geometry. ACM Trans. on Graphics (TOG), 31(5):1-10, 2012. 1, 3", + "[4] Matthias Grundmann, Vivek Kwatra, Daniel Castro, and Irfan Essa. Calibration-free rolling shutter removal. In Proc. ICCP, pages 1-8, 2012. 2, 3", + "[5] Matthias Grundmann, Vivek Kwatra, and Irfan Essa. Autodirected video stabilization with robust 11 optimal camera paths. In Proc. CVPR, pages 225-232, 2011. 1, 2, 6", + "[6] Wilko Guilluy, Laurent Oudre, and Azedine Beghdadi. Video stabilization: Overview, challenges and perspectives. Signal Processing: Image Communication, 90:116015, 2021. 1", + "[7] Richard Hartley and Andrew Zisserman. Multiple view geometry in computer vision. Cambridge university press, 2003. 3", + "[8] Mingbo Hong, Yuhang Lu, Nianjin Ye, Chunyu Lin, Qijun Zhao, and Shuaicheng Liu. Unsupervised homography estimation with coplanarity-aware gan. In Proc. CVPR, pages 17663-17672, 2022. 1, 3", + "[9] Jie Hu, Li Shen, and Gang Sun. Squeeze-and-excitation networks. In Proc. CVPR, pages 7132-7141, 2018. 4", + "[10] Chia-Hung Huang, Hang Yin, Yu-Wing Tai, and Chi-Keung Tang. Stablenet: semi-online, multi-scale deep video stabilization. arXiv preprint arXiv:1907.10283, 2019. 4", + "[11] Maria Silvia Ito and Ebroul Izquierdo. A dataset and evaluation framework for deep learning based video stabilization systems. In Proc. VCIP, pages 1-4. IEEE, 2019. 4", + "[12] Dengchao Jin, Jianjun Lei, Bo Peng, Wanqing Li, Nam Ling, and Qingming Huang. Deep affine motion compensation network for inter prediction in vvc. IEEE Trans. on Circuits and Systems for Video Technology, 32(6):3923-3933, 2021. 1", + "[13] Neel Joshi, Wolf Kienzle, Mike Toelle, Matt Uytendaele, and Michael F Cohen. Real-time hyperlapse creation via optimal frame selection. ACM Transactions on Graphics (TOG), 34(4):1-9, 2015. 3", + "[14] Alexandre Karpenko, David Jacobs, Jongmin Baek, and Marc Levoy. Digital video stabilization and rolling shutter correction using gyroscopes. CSTR, 1(2):13, 2011. 3", + "[15] Johannes Kopf. 360 video stabilization. ACM Transactions on Graphics (TOG), 35(6):1-9, 2016. 3", + "[16] Ken-Yi Lee, Yung-Yu Chuang, Bing-Yu Chen, and Ming Ouhyoung. Video stabilization using robust feature trajectories. In Proc. CVPR, pages 1397-1404, 2009. 2", + "[17] Yao-Chih Lee, Kuan-Wei Tseng, Yu-Ta Chen, Chien-Cheng Chen, Chu-Song Chen, and Yi-Ping Hung. 3d video stabilization with depth estimation by cnn-based optimization. In Proc. CVPR, pages 10621–10630, 2021. 1" + ], + "bbox": [ + 78, + 114, + 470, + 900 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "[18] Feng Liu, Michael Gleicher, Hailin Jin, and Aseem Agarwala. Content-preserving warps for 3d video stabilization. ACM Trans. on Graphics (ToG), 28(3):1-9, 2009. 1, 3", + "[19] Feng Liu, Michael Gleicher, Jue Wang, Hailin Jin, and Aseem Agarwala. Subspace video stabilization. ACM Trans. on Graphics (TOG), 30(1):1-10, 2011. 3", + "[20] Shuaicheng Liu, Mingyu Li, Shuyuan Zhu, and Bing Zeng. Codingflow: Enable video coding for video stabilization. IEEE Trans. on Image Processing, 26(7):3291-3302, 2017. 1, 3", + "[21] Shuaicheng Liu, Yuhang Lu, Hai Jiang, Nianjin Ye, Chuan Wang, and Bing Zeng. Unsupervised global and local homography estimation with motion basis learning. IEEE Trans. on Pattern Analysis and Machine Intelligence, 2022. 1", + "[22] Shuaicheng Liu, Ping Tan, Lu Yuan, Jian Sun, and Bing Zeng. Meshflow: Minimum latency online video stabilization. In Proc. ECCV, pages 800-815, 2016. 1, 2, 3, 6, 7", + "[23] Shuaicheng Liu, Yinting Wang, Lu Yuan, Jiajun Bu, Ping Tan, and Jian Sun. Video stabilization with a depth camera. In Proc. CVPR, pages 89-95, 2012. 1, 3", + "[24] Shuaicheng Liu, Nianjin Ye, Chuan Wang, Kunming Luo, Jue Wang, and Jian Sun. Content-aware unsupervised deep homography estimation and beyond. IEEE Trans. on Pattern Analysis and Machine Intelligence, 2022. 1", + "[25] Shuaicheng Liu, Lu Yuan, Ping Tan, and Jian Sun. Bundled camera paths for video stabilization. ACM Trans. on Graphics (TOG), 32(4):1-10, 2013. 1, 2, 3, 6, 7", + "[26] Shuaicheng Liu, Lu Yuan, Ping Tan, and Jian Sun. Steadyflow: Spatially smooth optical flow for video stabilization. In Proc. CVPR, pages 4209-4216, 2014. 1, 2, 3", + "[27] Yasuyuki Matsushita, Eyal Ofek, Weina Ge, Xiaou Tang, and Heung-Yeung Shum. Full-frame video stabilization with motion inpainting. IEEE Trans. on Pattern Analysis and Machine Intelligence, 28(7):1150-1163, 2006. 1, 2", + "[28] Lang Nie, Chunyu Lin, Kang Liao, Shuaicheng Liu, and Yao Zhao. Depth-aware multi-grid deep homography estimation with contextual correlation. IEEE Trans. on Circuits and Systems for Video Technology, 32(7):4460-4472, 2022. 1", + "[29] Hui Qu, Li Song, and Gengjian Xue. Shaking video synthesis for video stabilization performance assessment. In Proc. VCIP, pages 1-6. IEEE, 2013. 4", + "[30] Ethan Rublee, Vincent Rabaud, Kurt Konolige, and Gary Bradski. Orb: An efficient alternative to sift or surf. In Proc. ICCV, pages 2564-2571, 2011. 2", + "[31] Jianbo Shi et al. Good features to track. In Proc. CVPR, pages 593-600, 1994. 2", + "[32] Brandon M Smith, Li Zhang, Hailin Jin, and Aseem Agarwala. Light field video stabilization. In Proc. ICCV, pages 341-348, 2009. 3", + "[33] Miao Wang, Guo-Ye Yang, Jin-Kun Lin, Song-Hai Zhang, Ariel Shamir, Shao-Ping Lu, and Shi-Min Hu. Deep online video stabilization with multi-grid warping transformation learning. IEEE Trans. on Image Processing, 28(5):2283-2292, 2018. 1, 2, 3, 4, 5, 6, 7, 8", + "[34] Yu-Shuen Wang, Feng Liu, Pu-Sheng Hsu, and Tong-Yee Lee. Spatially and temporally optimized video stabiliza" + ], + "bbox": [ + 501, + 92, + 890, + 900 + ], + "page_idx": 8 + }, + { + "type": "page_number", + "text": "23038", + "bbox": [ + 478, + 944, + 519, + 955 + ], + "page_idx": 8 + }, + { + "type": "list", + "sub_type": "ref_text", + "list_items": [ + "tion. IEEE Trans. on Visualization and Computer Graphics, 19(8):1354-1361, 2013. 2, 3", + "[35] Sen-Zhe Xu, Jun Hu, Miao Wang, Tai-Jiang Mu, and ShiMin Hu. Deep video stabilization using adversarial networks. In Computer Graphics Forum, volume 37, pages 267-276, 2018. 1, 3", + "[36] Yufei Xu, Jing Zhang, Stephen J Maybank, and Dacheng Tao. Dut: Learning video stabilization by simply watching unstable videos. IEEE Trans. on Image Processing, 31:4306-4320, 2022. 6", + "[37] Junlan Yang, Dan Schonfeld, Chong Chen, and Magdi Mohamed. Online video stabilization based on particle filters. In Proc. ICIP, pages 1545-1548, 2006. 3", + "[38] Nianjin Ye, Chuan Wang, Haoqiang Fan, and Shuaicheng Liu. Motion basis learning for unsupervised deep homography estimation with subspace projection. In Proc. ICCV, pages 13117-13125, October 2021. 1, 3", + "[39] Nianjin Ye, Chuan Wang, Shuaicheng Liu, Lanpeng Jia, Jue Wang, and Yongqing Cui. Deepmeshflow: Content adaptive mesh deformation for robust image registration. arXiv preprint arXiv:1912.05131, 2019. 1, 2, 3, 4, 5", + "[40] Jiyang Yu and Ravi Ramamoorthi. Robust video stabilization by optimization in cnn weight space. In Proc. CVPR, pages 3800-3808, 2019. 3", + "[41] Jiyang Yu and Ravi Ramamoorthi. Learning video stabilization using optical flow. In Proc. CVPR, pages 8159-8167, 2020. 1, 3, 6", + "[42] Jiyang Yu, Ravi Ramamoorthi, Keli Cheng, Michel Sarkis, and Ning Bi. Real-time selfie video stabilization. In Proc. CVPR, pages 12036-12044, 2021. 3", + "[43] Minda Zhao and Qiang Ling. Pwstablenet: Learning pixelwise warping maps for video stabilization. IEEE Trans. on Image Processing, 29:3582-3595, 2020. 6, 7, 8" + ], + "bbox": [ + 78, + 90, + 468, + 560 + ], + "page_idx": 9 + }, + { + "type": "page_number", + "text": "23039", + "bbox": [ + 478, + 944, + 517, + 955 + ], + "page_idx": 9 + } +] \ No newline at end of file diff --git a/2023/Minimum Latency Deep Online Video Stabilization/5c08d8de-7fcf-430c-a7d0-16aae326aed4_model.json b/2023/Minimum Latency Deep Online Video Stabilization/5c08d8de-7fcf-430c-a7d0-16aae326aed4_model.json new file mode 100644 index 0000000000000000000000000000000000000000..f6a515ea2e62fe2f12bb081838097266040767da --- /dev/null +++ b/2023/Minimum Latency Deep Online Video Stabilization/5c08d8de-7fcf-430c-a7d0-16aae326aed4_model.json @@ -0,0 +1,2508 @@ +[ + [ + { + "type": "header", + "bbox": [ + 0.107, + 0.003, + 0.182, + 0.043 + ], + "angle": 0, + "content": "CVF" + }, + { + "type": "header", + "bbox": [ + 0.239, + 0.001, + 0.808, + 0.047 + ], + "angle": 0, + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + }, + { + "type": "title", + "bbox": [ + 0.226, + 0.131, + 0.745, + 0.154 + ], + "angle": 0, + "content": "Minimum Latency Deep Online Video Stabilization" + }, + { + "type": "text", + "bbox": [ + 0.136, + 0.187, + 0.838, + 0.242 + ], + "angle": 0, + "content": "Zhuofan Zhang\\(^{1*}\\) Zhen Liu\\(^{2*}\\) Ping Tan\\(^{3}\\) Bing Zeng\\(^{1}\\) Shuaicheng Liu\\(^{1,2\\dagger}\\) \n\\(^{1}\\)University of Electronic Science and Technology of China \\(^{2}\\)Megvii Technology \n\\(^{3}\\)The Hong Kong University of Science and Technology" + }, + { + "type": "text", + "bbox": [ + 0.246, + 0.244, + 0.721, + 0.277 + ], + "angle": 0, + "content": "{zhangzf98@std., eezeng@, liushuaicheng@}uestc.edu.cn, liuzhen03@megvii.com, pingtan@ust.hk" + }, + { + "type": "title", + "bbox": [ + 0.235, + 0.312, + 0.314, + 0.329 + ], + "angle": 0, + "content": "Abstract" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.344, + 0.474, + 0.692 + ], + "angle": 0, + "content": "We present a novel camera path optimization framework for the task of online video stabilization. Typically, a stabilization pipeline consists of three steps: motion estimating, path smoothing, and novel view rendering. Most previous methods concentrate on motion estimation, proposing various global or local motion models. In contrast, path optimization receives relatively less attention, especially in the important online setting, where no future frames are available. In this work, we adopt recent off-the-shelf high-quality deep motion models for motion estimation to recover the camera trajectory and focus on the latter two steps. Our network takes a short 2D camera path in a sliding window as input and outputs the stabilizing warp field of the last frame in the window, which warps the coming frame to its stabilized position. A hybrid loss is well-defined to constrain the spatial and temporal consistency. In addition, we build a motion dataset that contains stable and unstable motion pairs for the training. Extensive experiments demonstrate that our approach significantly outperforms state-of-the-art online methods both qualitatively and quantitatively and achieves comparable performance to offline methods. Our code and dataset are available at https://github.com/1iuzhen03/NNDVS." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.72, + 0.21, + 0.736 + ], + "angle": 0, + "content": "1. Introduction" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.745, + 0.47, + 0.868 + ], + "angle": 0, + "content": "Video stabilization methods aim at removing unwanted shaky motions of a video caused by unsteady moving capture [6]. Traditional methods often take three main steps: 1) camera motion estimating for trajectory recovery; 2) camera path smoothing; and 3) steady frame synthesis. According to the adopted motion model in the first step, these methods can be broadly classified as 2D or 3D. 2D methods adopt planar motion models such as affine [5], or homog-" + }, + { + "type": "image", + "bbox": [ + 0.507, + 0.314, + 0.887, + 0.374 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.567, + 0.378, + 0.817, + 0.392 + ], + "angle": 0, + "content": "(a) Illustration of the dataset synthesis process." + }, + { + "type": "image", + "bbox": [ + 0.504, + 0.408, + 0.695, + 0.491 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.568, + 0.498, + 0.816, + 0.511 + ], + "angle": 0, + "content": "(b) Illustration of the synthesized camera path." + }, + { + "type": "image", + "bbox": [ + 0.7, + 0.408, + 0.89, + 0.491 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.498, + 0.517, + 0.893, + 0.573 + ], + "angle": 0, + "content": "Figure 1. Illustration of the dataset synthesis process (a) and the synthesized camera path (b). We transfer an unstable path to a stable path, creating a synthesized path, which shares high frequencies of the unstable path with low frequencies of the stable path." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.598, + 0.892, + 0.644 + ], + "angle": 0, + "content": "raphy [27], or mesh [25, 22, 33], or flow [26, 20, 41], while 3D methods resort to 3D depth [23, 17], or reconstructed points [18], or epipolar geometry constraints [3]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.644, + 0.893, + 0.765 + ], + "angle": 0, + "content": "In comparison, deep learning-based methods learn stabilization models from stable and unstable video pairs [33, 41, 35] without explicit steps of motion estimation and smoothing. However, the results of deep methods are often visually inferior to those of traditional ones. A potential reason is that these methods try to learn the three steps all in a unified framework, each of which has different characteristics but is learned in the network blindly." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.765, + 0.895, + 0.902 + ], + "angle": 0, + "content": "On the other hand, deep affine [12], deep homography [38, 8], and deep mesh models [39, 24, 21, 28] have demonstrated high-quality image registration, even under adverse cases. They are robust to scenes with large depth variation, large dynamic objects, and poor textures, fitting perfectly for the camera motion estimation. In this work, we argue that it is not necessary to enclose all three steps of the stabilization into the learning pipeline, but let the motion estimation to the recent deep motion models [39, 24]." + }, + { + "type": "page_footnote", + "bbox": [ + 0.096, + 0.875, + 0.204, + 0.888 + ], + "angle": 0, + "content": "*Equal contribution" + }, + { + "type": "page_footnote", + "bbox": [ + 0.098, + 0.888, + 0.22, + 0.9 + ], + "angle": 0, + "content": "† Corresponding author" + }, + { + "type": "list", + "bbox": [ + 0.096, + 0.875, + 0.22, + 0.9 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.521, + 0.958 + ], + "angle": 0, + "content": "23030" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.47, + 0.137 + ], + "angle": 0, + "content": "In this way, our network only focuses on learning to stabilize the shaky camera motion, which makes the learning process much more efficient and effective." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.139, + 0.468, + 0.289 + ], + "angle": 0, + "content": "Camera path smoothing can be performed offline or online, where the former optimizes the path globally while the latter smooths the path on-the-fly. In other words, offline approaches have access to all past and future frames during optimization, as it often stabilizes a video after it is captured. In contrast, online methods aim to stabilize a video during the capture. Note that, the concept of real-time differs from that of online, as an online method must be in real-time whereas an offline method can run at real-time speed. The main distinction is the availability of future frames." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.292, + 0.468, + 0.563 + ], + "angle": 0, + "content": "Most existing methods are offline [25, 5, 4, 34, 26]. However, the online setting is critical as many applications desire instant visual feedback based on live video streams [22, 33]. Normally, with limited or even no access to future frames, online methods cannot achieve equal stability as offline methods, particularly in the suppression of the low-frequency camera shake, which frequently necessitates a long camera path. One may argue that online methods can have all the past frames for processing. However, future motions are important, if not more important than the past. Because, for one thing, fast camera motions can happen at any time suddenly, e.g., quick rotation or zooming. The reaction time is short. Inappropriate processing may either decrease the stability or create artifacts such as excessive cropping. For another, all the past frames have already been shown to the audience, meaning that they are fixed, and thus cannot be modified. We can only adjust the unstabled future frames to the frozen past ones." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.566, + 0.468, + 0.883 + ], + "angle": 0, + "content": "To this end, we propose a deep online camera path smooth network that takes a pre-estimated short 2D camera trajectory in a sliding window as input and outputs the motion compensation warp field of the last frame in the window for the stabilized view, which is the setting of online stabilization with the minimum latency. A video can be stabilized on the fly by applying our model repeatedly for every incoming frame. To deal with depth changes and moving objects, we employ the mesh-based motion model [39] which demonstrates excellent robustness in various scenes. Instead of directly inputting the mesh structure or mesh cells as local homographies to the network, we convert the estimated motion to a dense flow field, which can be fed into the convolutional neural network naturally. We show that it is a more convenient representation compared to other alternatives, e.g., vertex sparse motion vectors or homography matrix, which cannot be easily adapted as input to CNNs. Based on that, we further propose a hybrid loss, which consists of the motion-consistency loss, the shape-consistency loss, and the scale-preserving loss, to maintain the spatial coherence and temporal continuity of the stabilized video." + }, + { + "type": "text", + "bbox": [ + 0.097, + 0.886, + 0.468, + 0.9 + ], + "angle": 0, + "content": "Besides, we create a motion dataset, MotionStab, to" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.092, + 0.892, + 0.286 + ], + "angle": 0, + "content": "train our network. In particular, we capture 110 stable videos with a cell phone mounted on a hand-held physical stabilizer. Then, we create a shaky video by transforming each frame of the stable video according to the motion of another irrelevant shaky video. In this way, the stable and unstable motion pairs can be constructed. Fig. 1 shows our idea. Note that, our dataset is different from DeepStab [33], which is captured by a stable and a shaky camera simultaneously. We directly transfer the motion of a shaky video to a stable video. The contents of the two videos are not important but the motion does. That means DeepStab [33] offers frame pairs, while our MotionStab offers motion pairs. We feed the motions to the network instead of RGB frames." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.289, + 0.892, + 0.454 + ], + "angle": 0, + "content": "The benefits are three folds: 1) image contents are diverse, while motion mappings are much easier to learn; 2) motion as mesh is lightweight, so does the network; 3) the network can be more focused by excluding the task of the motion estimation. As a result, we show that this motion learning pipeline is effective enough, such that it can work with straightforward network architectures, e.g., UNet, without help from more advanced designs or sophisticated modules. Complex motion types can be learned by the network successfully, as long as they exist in the training data. As such, the network can be kept simple yet effective." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.455, + 0.892, + 0.484 + ], + "angle": 0, + "content": "In summary, the main contributions of this paper are concluded as follows:" + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.497, + 0.891, + 0.526 + ], + "angle": 0, + "content": "- We propose a novel deep camera path optimization framework for online video stabilization." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.54, + 0.892, + 0.584 + ], + "angle": 0, + "content": "- We propose a hybrid loss to enable robust supervision for maintaining the spatial and temporal coherence of the stabilized video." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.598, + 0.891, + 0.628 + ], + "angle": 0, + "content": "- We build a comprehensive MotionStab dataset that covers various motions for camera path optimization." + }, + { + "type": "text", + "bbox": [ + 0.519, + 0.64, + 0.891, + 0.684 + ], + "angle": 0, + "content": "- We conduct extensive experiments to demonstrate the effectiveness of the proposed approach against existing state-of-the-art online and offline methods." + }, + { + "type": "list", + "bbox": [ + 0.519, + 0.497, + 0.892, + 0.684 + ], + "angle": 0, + "content": null + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.701, + 0.65, + 0.716 + ], + "angle": 0, + "content": "2. Related Works" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.726, + 0.694, + 0.74 + ], + "angle": 0, + "content": "2.1. Traditional Methods" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.75, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Early 2D approaches track image features for several frames and then smooth these feature trajectories to stabilize a video [16, 34]. However, long feature tracks [31] are hard to be obtained when large camera motions exist. Later, motion models, such as affine [5] or homography [27, 2], are calculated between neighboring frames, relaxing the requirement of long feature tracks into feature matches [30] between adjacent frames. Then, these motion models are accumulated to generate a 2D camera trajectory, which is shown to be a good replacement against" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.946, + 0.518, + 0.957 + ], + "angle": 0, + "content": "23031" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.076, + 0.092, + 0.468, + 0.198 + ], + "angle": 0, + "content": "track-based approaches, owning largely improved robustness. With respect to the motion representation, homography mixture [4], mesh [25, 22, 34], and optical flow [26, 20] based motion models are proposed to deal with scenes that contain large depth variations. Besides, some approaches focus on special stabilization tasks, such as Selfie [42], 360 [15], and hyperlapse videos [13]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.199, + 0.468, + 0.394 + ], + "angle": 0, + "content": "On the other hand, 3D-based methods require 3D camera motions or scene structure for stabilization. The 3D structure can either be calculated from the video by structure-from-motion (SfM) [18] or acquired from additional hardware, such as a depth camera [23], a gyroscope sensor [14], or a light field camera [32]. However, full 3D stabilization is fragile and computationally expensive [18]. Partial 3D methods proposed 3D constraints, such as subspace projection [19] and epipolar geometry [3], to alleviate the requirement of full 3D reconstruction [7]. Normally, 3D methods can better handle the scene parallax compared with 2D approaches due to the physical correctness, as long as the 3D information can be available." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.405, + 0.3, + 0.421 + ], + "angle": 0, + "content": "2.2. Deep Learning Methods" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.429, + 0.468, + 0.595 + ], + "angle": 0, + "content": "Deep methods take the video frames as input and directly output the stabilized frames, which are often trained with stable and unstable frame pairs acquired by special hardware, e.g., DeepStab dataset [33]. Xu et al. used the adversarial network to generate a target image to guide the warping [35]. Yu et al. learned the flow fields from initial optical flow estimation for the accurate per-pixel motion compensation [41]. Deep methods suffer from the generalization problem, given that DeepStab only contains 60 videos. Yu et al. used the CNN as the optimizer instead of learning from data to overfit each input example [40]." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.596, + 0.468, + 0.701 + ], + "angle": 0, + "content": "Recently, deep motion models have achieved good results for motion estimation, such as deep homography [38, 8] and deep meshflow [39], which is more robust in adverse cases compared to traditional solutions, such as scenes of low texture and low light. In this work, we adopt the deep meshflow [39] for our camera motion estimator and design a network concentrating on camera path smoothing." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.711, + 0.262, + 0.728 + ], + "angle": 0, + "content": "2.3. Online Approaches" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Most of the video stabilization approaches are offline, where a video is processed after it has been captured. Online methods stabilize a video during the capture [37, 33, 22]. One may argue that global path optimization can be easily modified to online methods by applying a sliding window scheme. However, the stability would inevitably decrease, let alone the existence of challenging camera motions, such as quick rotation and zooming, which may introduce artifacts such as wobble and excessive cropping. Previously, these difficult motions can only be solved satisfactorily by global camera path smoothing. In this work," + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.092, + 0.892, + 0.122 + ], + "angle": 0, + "content": "we propose to solve these problems with our proposed deep online camera path optimization framework." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.135, + 0.635, + 0.153 + ], + "angle": 0, + "content": "3. Methodology" + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.16, + 0.702, + 0.175 + ], + "angle": 0, + "content": "3.1. Problem Formulation" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.183, + 0.892, + 0.304 + ], + "angle": 0, + "content": "Our method is built upon convolutional neural networks. As illustrated in Fig. 3 (a), given an incoming unsteady frame \\( I_{t} \\) at timestamp \\( t \\), our deep online video stabilization aims to predict the corresponding steady frame \\( I_{t}^{\\prime} \\) with no future frames. Here, we use “/” to represent predicted quantities. Note that, previous learning-based methods learn the mapping \\( f(\\cdot) \\) from the input shaky RGB frames and predict a warp field \\( B_{t}^{\\prime} \\) of frame \\( I_{t} \\), which can be formulated as" + }, + { + "type": "equation", + "bbox": [ + 0.635, + 0.316, + 0.892, + 0.334 + ], + "angle": 0, + "content": "\\[\n\\left\\{B _ {t} ^ {\\prime} \\right\\} = f \\left(\\left\\{I _ {t} \\right\\}\\right), \\tag {1}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.344, + 0.892, + 0.42 + ], + "angle": 0, + "content": "where \\(\\{\\cdot\\}\\) represents a set of elements. However, our experiments show that directly using complex RGB video frames as input and mixing motion estimation and path smoothing in a network frequently causes estimation errors, resulting in wobbling and distortion artifacts." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.421, + 0.892, + 0.587 + ], + "angle": 0, + "content": "In this work, we propose our approach from a novel perspective, where we separate the motion estimation step from the network alone and leave the network focus on camera path smoothing. Specifically, we consider using a fixed window of \\( r \\) past frames \\( \\{I_t\\}_r = \\langle I_{t - r},\\dots,I_{t - 1},I_t\\rangle \\) of minimum latency (i.e. without using future frames) to stabilize the incoming target frame \\( I_{t} \\). The camera motion \\( \\{F_t\\} \\) is estimated by an off-the-shelf deep motion estimation model. Our camera path smooth network uses only the estimated motion as input to predict the corresponding warp field \\( B_t' \\), i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.627, + 0.597, + 0.891, + 0.617 + ], + "angle": 0, + "content": "\\[\n\\left\\{B _ {t} ^ {\\prime} \\right\\} = \\Phi \\left(\\left\\{F _ {t} \\right\\}; \\theta\\right), \\tag {2}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.627, + 0.892, + 0.673 + ], + "angle": 0, + "content": "where \\(\\Phi(\\cdot)\\) denotes the camera path smoothing network and \\(\\theta\\) is the network parameters to be optimized. We empirically set \\(r\\) to 15 in our experiments." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.682, + 0.844, + 0.699 + ], + "angle": 0, + "content": "3.2. Deep Online Camera Path Optimization" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.705, + 0.892, + 0.827 + ], + "angle": 0, + "content": "As shown in Fig. 2, the overall pipeline of the proposed deep online camera path optimization framework mainly consists of three stages. Firstly, we adopt a deep motion extraction model for robust camera motion estimation. Secondly, the camera path smooth network takes the unsteady camera motion as input and predicts the smoothed warp field. Finally, the original shaky frame is transformed by the predicted warp field to synthesize the target steady frame." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.84, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Camera Motion Estimation The first step is to estimate the camera motion. We employ an optimized deep mesh-flow model [39] to extract the inter-frame motion. Specifically, given the incoming frame \\( I_{t} \\) and past adjacent frame" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "23032" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.103, + 0.089, + 0.87, + 0.328 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.334, + 0.895, + 0.378 + ], + "angle": 0, + "content": "Figure 2. The overall pipeline of the proposed deep online camera path optimization framework. (a) We first employ a deep motion extraction model to estimate the unsteady camera motion. (b) Then, the estimated motion is fed into the camera path smooth network, yielding the smoothed warp field. (c) Finally, the target steady frame is synthesized by the predicted smooth warp field." + }, + { + "type": "image", + "bbox": [ + 0.083, + 0.399, + 0.257, + 0.493 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.163, + 0.497, + 0.182, + 0.51 + ], + "angle": 0, + "content": "(a)" + }, + { + "type": "image", + "bbox": [ + 0.289, + 0.399, + 0.462, + 0.493 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.368, + 0.497, + 0.387, + 0.51 + ], + "angle": 0, + "content": "(b)" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.515, + 0.471, + 0.601 + ], + "angle": 0, + "content": "Figure 3. Relationships between the unstable/synthesized video and the stable video. (a) depicts the basic relationships of the unstable video \\(\\{I_t\\}\\) and stabilized video \\(\\{I_t'\\}\\), and (b) illustrates the main idea of our dataset synthesis strategy that transfers collected unstable motions \\(\\{F_t^{\\mathrm{ust}}\\}\\) to stable video frames \\(\\{I_t^{\\mathrm{stb}}\\}\\), generating synthesized unstable video frames \\(\\{I_t^{\\mathrm{syn}}\\}\\)." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.623, + 0.47, + 0.729 + ], + "angle": 0, + "content": "\\(I_{t - 1}\\) with size of \\(640\\times 360\\) we estimate \\(F_{t}\\) by model [39] (Fig. 3 (a), upper yellow part). Repeat this process, we accumulate a set of inter-frame motions, \\(\\{F_t\\}_{r - 1} = \\langle F_{t - r + 1},\\dots ,F_{t - 1},F_t\\rangle\\) . In particular, we keep the most recent \\(r - 1\\) motions in our buffer, where historical motions that are beyond range \\(r - 1\\) are simply dropped. The deep meshflow motion estimation is defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.196, + 0.739, + 0.469, + 0.756 + ], + "angle": 0, + "content": "\\[\nF _ {t} = \\downarrow_ {s} \\mathcal {M} _ {F} \\left(I _ {t}, I _ {t - 1}\\right), \\tag {3}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.765, + 0.469, + 0.856 + ], + "angle": 0, + "content": "where \\(\\mathcal{M}_F(\\cdot)\\) is the pre-trained deep meshflow model. \\(\\downarrow_{s}\\) indicates that we collect the sparse motions at the mesh vertexes, and shrink them pixel by pixel to form a downsampled dense motion field, for the purpose of feeding it to the CNNs. The scale factor \\(s\\) is set to 8, and the size of the dense motion field \\(F_{t}\\) is \\(80\\times 45\\)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.871, + 0.47, + 0.903 + ], + "angle": 0, + "content": "Camera Path Smooth Network Given the estimated camera motion \\(\\{F_t\\}_{r - 1}\\) as input, the camera path smooth net" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.4, + 0.892, + 0.522 + ], + "angle": 0, + "content": "work predicts the target smoothed warp field \\( B_{t}^{\\prime} \\) as Eq. 2. Note that, the meshflow model is spatially-variant, and so does the \\( F_{t} \\). Therefore, we provide spatial and temporal optimizations. The camera path smooth network is designed as an encoder-decoder architecture and we implement it as a 4-stage UNet with channels of 64, 128, 256, and 512. We further employ the channel attention mechanism (CA) [9] to adaptively learn the weights of different historical motions." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.537, + 0.892, + 0.613 + ], + "angle": 0, + "content": "Steady Frame Rendering After obtaining the warp field \\( B_{t}^{\\prime} \\), we inverse the process of shrinking, where we put the motions back to the sparse vertex locations to create a mesh, based on which we warp the shaky frame \\( I_{t} \\) to its stabilized position \\( I_{t}^{\\prime} \\):" + }, + { + "type": "equation", + "bbox": [ + 0.64, + 0.625, + 0.892, + 0.645 + ], + "angle": 0, + "content": "\\[\nI _ {t} ^ {\\prime} = \\mathcal {W} \\left(I _ {t}, B _ {t} ^ {\\prime}\\right), \\tag {4}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.655, + 0.892, + 0.687 + ], + "angle": 0, + "content": "where \\(\\mathcal{W}(\\cdot)\\) denotes the backward warping function. The first parameter is an image and the second is a warp field." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.696, + 0.667, + 0.712 + ], + "angle": 0, + "content": "3.3. Training Dataset" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.72, + 0.892, + 0.825 + ], + "angle": 0, + "content": "Existing training datasets are either captured simultaneously by two cameras [33] or synthesized by simulated injected noise [10, 29, 11]. The former would naturally suffer from parallax problems, while the latter makes the synthesized video paths unrealistic. To address this issue, we offer a novel synthetic method that can build realistic unstable/stable motion pairs from existing shaky videos." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.894, + 0.903 + ], + "angle": 0, + "content": "Our main idea is to transfer the motion of an unstable shaky video \\( V_{\\mathrm{ust}} \\) to a stable video \\( V_{\\mathrm{stb}} \\), yielding another synthesized shaky video \\( V_{\\mathrm{syn}} \\) with motions from \\( V_{\\mathrm{ust}} \\) but image contents as \\( V_{\\mathrm{stb}} \\). The videos \\( V_{\\mathrm{ust}} \\) and \\( V_{\\mathrm{stb}} \\) are irrelevant. Let's denote \\( \\{I_t^{\\mathrm{ust}}\\} \\), \\( \\{I_t^{\\mathrm{stb}}\\} \\), \\( \\{I_t^{\\mathrm{syn}}\\} \\) as video frames and" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "23033" + } + ], + [ + { + "type": "text", + "bbox": [ + 0.078, + 0.09, + 0.468, + 0.122 + ], + "angle": 0, + "content": "\\(\\{F_t^{\\mathrm{ust}}\\} ,\\{F_t^{\\mathrm{stb}}\\} ,\\{F_t^{\\mathrm{syn}}\\}\\) as motion between frames of video \\(\\mathbf{V}_{\\mathrm{ust}},\\mathbf{V}_{\\mathrm{stb}},\\mathbf{V}_{\\mathrm{syn}}\\) accordingly." + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.122, + 0.468, + 0.184 + ], + "angle": 0, + "content": "To achieve this, we first estimate the motions \\(\\{F_t^{\\mathrm{ust}}\\}\\), \\(\\{F_t^{\\mathrm{stb}}\\}\\) between adjacent frames of \\(V_{\\mathrm{ust}}\\) and \\(V_{\\mathrm{stb}}\\) by deep meshflow [39]. Next, we warp the frame \\(\\{I_t^{\\mathrm{stb}}\\}\\) by motion \\(\\{F_t^{\\mathrm{ust}}\\}\\) to produce \\(\\{I_t^{\\mathrm{syn}}\\}\\), for each timestamp \\(t\\):" + }, + { + "type": "equation", + "bbox": [ + 0.202, + 0.189, + 0.468, + 0.207 + ], + "angle": 0, + "content": "\\[\nI _ {t} ^ {\\text {s y n}} = \\mathcal {W} \\left(I _ {t} ^ {\\text {s t b}}, F _ {t} ^ {\\text {u s t}}\\right). \\tag {5}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.214, + 0.468, + 0.274 + ], + "angle": 0, + "content": "Applying Eq. 5 to every frame of \\( V_{\\mathrm{stb}} \\) creates the desired \\( V_{\\mathrm{syn}} \\). The \\( V_{\\mathrm{stb}} \\) and \\( V_{\\mathrm{syn}} \\) become a pair of stable/unstable videos, where the following motion equality holds (Please refer to Fig. 3 (b) for the relation), for each timestamp \\( t \\):" + }, + { + "type": "equation", + "bbox": [ + 0.18, + 0.295, + 0.468, + 0.313 + ], + "angle": 0, + "content": "\\[\nF _ {t} ^ {\\text {u s t}} + F _ {t} ^ {\\text {s y n}} = F _ {t} ^ {\\text {s t b}} + F _ {t - 1} ^ {\\text {u s t}}, \\tag {6}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.321, + 0.468, + 0.352 + ], + "angle": 0, + "content": "where \\(F_{t}^{\\mathrm{ust}}\\), \\(F_{t}^{\\mathrm{stb}}\\) have been calculated which are known. Therefore, \\(F_{t}^{\\mathrm{syn}}\\) can be calculated as:" + }, + { + "type": "equation", + "bbox": [ + 0.18, + 0.358, + 0.468, + 0.376 + ], + "angle": 0, + "content": "\\[\nF _ {t} ^ {\\text {s y n}} = F _ {t} ^ {\\text {s t b}} + F _ {t - 1} ^ {\\text {u s t}} - F _ {t} ^ {\\text {u s t}}. \\tag {7}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.383, + 0.468, + 0.488 + ], + "angle": 0, + "content": "During the training, our network takes a subset of motions \\(\\{F_t^{\\mathrm{syn}}\\}_{r - 1} = \\langle F_{t - r + 1}^{\\mathrm{syn}},\\dots ,F_{t - 1}^{\\mathrm{syn}},F_t^{\\mathrm{syn}}\\rangle\\) as input and output a motion field that is as close as the ground-truth label \\(-F_{t}^{\\mathrm{ust}}\\), which is the inverse motion of \\(F_{t}^{\\mathrm{ust}}\\) as shown in Fig. 3 (b). On the other hand, the generated videos \\(V_{\\mathrm{stb}}\\) and \\(V_{\\mathrm{syn}}\\) are not important, as all we need are motions that can be calculated and derived by relations." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.489, + 0.468, + 0.669 + ], + "angle": 0, + "content": "To further establish the training dataset, we collected 110 stable videos of five categories (including regular, rotation, zooming, parallax, and crowd) using a cell phone mounted on a hand-held physical stabilizer. Next, we collected over 150 unstable videos from the website. Subsequently, we performed data synthesis on the collected stable and unstable videos by employing the aforementioned method, constructing the MotionStab dataset, which contains paired unstable/stable camera motion of various complex scenarios. As illustrated in Fig. 1 (b), the camera path of the synthesized video pairs is well-registered and realistic as the original unstable one." + }, + { + "type": "title", + "bbox": [ + 0.078, + 0.677, + 0.22, + 0.693 + ], + "angle": 0, + "content": "3.4. Training Loss" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.701, + 0.468, + 0.79 + ], + "angle": 0, + "content": "To train the camera path smooth network, we define several losses in our framework: the motion-consistency loss for maintaining motion continuity between consecutive frames, the shape-consistency loss for preserving the geometry of the predicted warp field, and the scale-preserving loss for maintaining the scale of the predicted warp field." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.806, + 0.468, + 0.866 + ], + "angle": 0, + "content": "Motion-consistency Loss To keep the continuity of the predicted consecutive video frames, the inter-frame motion of the stabilized video \\( F_{t}^{\\prime} \\) should be as similar as the ground truth one \\( \\hat{F}_{t} \\), i.e.," + }, + { + "type": "equation", + "bbox": [ + 0.201, + 0.871, + 0.468, + 0.898 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {M C}} = \\left\\| F _ {t} ^ {\\prime} - \\hat {F} _ {t} \\right\\| _ {1}. \\tag {8}\n\\]" + }, + { + "type": "image", + "bbox": [ + 0.518, + 0.091, + 0.657, + 0.194 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.523, + 0.198, + 0.657, + 0.213 + ], + "angle": 0, + "content": "(a) original meshgrid" + }, + { + "type": "image", + "bbox": [ + 0.721, + 0.092, + 0.862, + 0.194 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.717, + 0.197, + 0.878, + 0.212 + ], + "angle": 0, + "content": "(b) transformed meshgrid" + }, + { + "type": "image_caption", + "bbox": [ + 0.499, + 0.216, + 0.892, + 0.27 + ], + "angle": 0, + "content": "Figure 4. Illustration of the shape-consistency loss and the scale-preserving loss. The shape-consistency loss is employed to preserve the geometry shape of a meshgrid and the scale-preserving loss is used to maintain the scale." + }, + { + "type": "text", + "bbox": [ + 0.5, + 0.294, + 0.891, + 0.323 + ], + "angle": 0, + "content": "According to the relationship of Fig. 3 (a), Eq. 8 can be written as" + }, + { + "type": "equation", + "bbox": [ + 0.514, + 0.33, + 0.891, + 0.386 + ], + "angle": 0, + "content": "\\[\n\\begin{array}{l} \\mathcal {L} _ {\\mathrm {M C}} = \\left\\| \\left(F _ {t} + B _ {t - 1} ^ {\\prime} - B _ {t} ^ {\\prime}\\right) - \\left(F _ {t} + \\hat {B} _ {t - 1} - \\hat {B} _ {t}\\right) \\right\\| _ {1} (9) \\\\ = \\left\\| B _ {t - 1} ^ {\\prime} - B _ {t} ^ {\\prime} - \\hat {B} _ {t - 1} + \\hat {B} _ {t} \\right\\| _ {1}, (10) \\\\ \\end{array}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.398, + 0.891, + 0.444 + ], + "angle": 0, + "content": "where \\( B_{t}^{\\prime} \\) denotes network output of the predicted warp field. That is to say, the motion continuity can be restrained by the ground truth warp field \\( \\hat{B}_{t} \\) and \\( \\hat{B}_{t - 1} \\)." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.459, + 0.891, + 0.519 + ], + "angle": 0, + "content": "Shape-consistency Loss The shape-consistency loss is effective to prevent the distortion problem of the predicted warp field. Following Wang et al. [33], we implement the SC loss as an intra-grid loss term and an inter-grid loss term:" + }, + { + "type": "equation", + "bbox": [ + 0.625, + 0.546, + 0.891, + 0.561 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {S C}} = \\mathcal {L} _ {\\text {i n t r a}} + \\mathcal {L} _ {\\text {i n t e r}}. \\tag {11}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.573, + 0.891, + 0.617 + ], + "angle": 0, + "content": "Note that each pixel of our dense warp field is actually a vertex of the mesh grid. As depicted in Fig. 4, the intra-grid loss term is defined as:" + }, + { + "type": "equation", + "bbox": [ + 0.558, + 0.626, + 0.891, + 0.662 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {i n t r a}} = \\frac {1}{N} \\sum_ {v _ {i}} \\left\\| \\left(v _ {i} ^ {1} - v _ {i}\\right) \\cdot \\left(v _ {i} ^ {2} - v _ {i}\\right) \\right\\| _ {1}, \\tag {12}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.672, + 0.891, + 0.717 + ], + "angle": 0, + "content": "where \\( i \\) denotes the \\( i \\)-th vertex and \\( N \\) is the total number of vertices. Besides, the inter-grid loss term is used to maintain the geometric consistency of adjacent grids:" + }, + { + "type": "equation", + "bbox": [ + 0.54, + 0.727, + 0.891, + 0.763 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\text {i n t e r}} = \\frac {1}{N} \\sum_ {v _ {i}} \\left\\| \\left(v _ {i} ^ {1} - v _ {i}\\right) - \\left(v _ {i} - v _ {i} ^ {3}\\right) \\right\\| _ {1}. \\tag {13}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.773, + 0.891, + 0.834 + ], + "angle": 0, + "content": "Scale-preserving Loss Since we convert the sparse motions at the mesh vertexes as a dense motion field and predict the mesh warp field, we introduce a scale-preserving loss to maintain the scale consistency of the predicted warp field:" + }, + { + "type": "equation", + "bbox": [ + 0.576, + 0.856, + 0.891, + 0.898 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} _ {\\mathrm {S P}} = \\frac {1}{N} \\sum_ {v _ {i}} \\left\\| \\frac {\\left\\| v _ {i} ^ {1} - v _ {i} \\right\\| _ {2}}{s} - 1 \\right\\| _ {1}. \\tag {14}\n\\]" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "23034" + } + ], + [ + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.088, + 0.892, + 0.129 + ], + "angle": 0, + "content": "Table 1. Quantitative comparisons on the NUS dataset [25]. We use the Cropping ratio (C), the Distortion value (D), and the Stability score (S) as evaluation metrics. All of these metrics are in the range of 0 to 1, and the higher the better. The \\(*\\) denotes the results of Bundled [25] are computed directly from the NUS dataset. The bests are marked in red and the second bests are in blue." + }, + { + "type": "table", + "bbox": [ + 0.1, + 0.13, + 0.875, + 0.458 + ], + "angle": 0, + "content": "
MethodsRegularRotationZooming
CDSCDSCDS
Offline* Bundled [25]0.66580.94090.90480.64770.86920.91940.57730.90730.9236
Robust L1 [5]0.71570.92520.84540.72060.82310.86170.71070.83290.7730
DIFRINT [1]0.98540.95550.81770.94130.88130.87010.95280.85310.8763
Yu et al. [41]0.94860.97520.84270.76610.76160.93170.89710.86300.9107
PWStableNet [43]0.93190.98520.81620.88010.97070.92510.93030.97920.8906
DUT [36]0.94850.96000.87170.76090.69400.92030.89860.86060.9221
OnlineMeshflow [22]0.80810.91680.83860.75780.76790.90920.77730.87150.8839
StabNet [33]0.74910.83930.84060.74170.72050.83840.73760.78070.8697
Ours0.94330.99170.80300.90210.98470.93410.91850.97360.8982
MethodsCrowdParallaxAvg.
CDSCDSCDS
Offline* Bundled [25]0.66850.89100.87440.71580.89650.89640.65500.90100.9037
Robust L1 [5]0.72080.90770.85040.71320.80540.87780.71620.85890.8417
DIFRINT [1]0.96620.87130.84560.97460.88230.86000.96410.88870.8539
Yu et al. [41]0.90810.91910.86600.92090.92190.88960.88820.88720.8881
PWStableNet [43]0.91810.97900.81620.92440.98020.85490.91700.97890.8606
DUT [36]0.89860.86170.90420.92540.87740.91270.88600.85070.9062
OnlineMeshflow [22]0.78880.82460.82800.81210.84290.84880.78820.87620.8617
StabNet [33]0.72470.77250.79120.69670.76600.82890.72800.77580.8338
Ours0.92470.98160.84080.93260.98270.87620.92420.98290.8705
" + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.476, + 0.47, + 0.506 + ], + "angle": 0, + "content": "where \\( s \\) is the scale factor in Eq. 3. Eventually, the overall loss is the combination of the above three loss terms:" + }, + { + "type": "equation", + "bbox": [ + 0.181, + 0.52, + 0.47, + 0.537 + ], + "angle": 0, + "content": "\\[\n\\mathcal {L} = \\mathcal {L} _ {\\mathrm {M C}} + \\alpha \\mathcal {L} _ {\\mathrm {S C}} + \\beta \\mathcal {L} _ {\\mathrm {S P}}, \\tag {15}\n\\]" + }, + { + "type": "text", + "bbox": [ + 0.078, + 0.549, + 0.357, + 0.565 + ], + "angle": 0, + "content": "where \\(\\alpha\\) and \\(\\beta\\) are empirically set to 0.01." + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.579, + 0.283, + 0.596 + ], + "angle": 0, + "content": "4. Experimental Results" + }, + { + "type": "title", + "bbox": [ + 0.077, + 0.605, + 0.295, + 0.621 + ], + "angle": 0, + "content": "4.1. Implementation Details" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.629, + 0.47, + 0.87 + ], + "angle": 0, + "content": "Evaluation Metrics For quantitative comparison, we employ three widely used metrics: cropping ratio, distortion value, and stability score, as in prior methods [25, 36, 43, 22]. For cropping ratio and distortion value, we first fit a global homography between the input and output videos at each frame. The cropping ratio measures the remaining frame area after cropping out undefined pixels due to motion compensation and is computed as the average scale component of the entire video. The distortion value, which is defined as the worst ratio of the two largest eigenvalues of the affine component across all frames, measures the anisotropic scaling of the homography between the input and output frames. The stability score measures the smoothness of the stabilized videos and the camera path is utilized to determine the value. We compute this metric by using a frequency domain analysis as in Bundled [25]." + }, + { + "type": "text", + "bbox": [ + 0.077, + 0.871, + 0.469, + 0.902 + ], + "angle": 0, + "content": "Implementation Details Our network is implemented by PyTorch. We use Adam as the optimizer for training, with" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.476, + 0.892, + 0.643 + ], + "angle": 0, + "content": "an initial learning rate of \\(1 \\times 10^{-4}\\) and no weight decay. We set \\(\\beta_{1} = 0.9\\), \\(\\beta_{2} = 0.999\\), and \\(\\epsilon = 1e - 8\\), respectively. We train the network for 100,000 iterations. The overall training time on two NVIDIA 1080Ti GPUs is 20 hours. During training, two adjacent frames and their corresponding historical frames are selected as a training sample. The MotionStab dataset comprises 65238 training samples in total. For inference, the overall framework can process a frame of size \\(640 \\times 360\\) in real-time. Specifically, we spend 12 ms, 10 ms, and 4 ms to extract camera motion, smooth the camera path, and synthesize stable frames, respectively." + }, + { + "type": "title", + "bbox": [ + 0.499, + 0.651, + 0.816, + 0.668 + ], + "angle": 0, + "content": "4.2. Comparisons with Existing Methods" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.675, + 0.892, + 0.825 + ], + "angle": 0, + "content": "To evaluate the proposed approach, we compare it with the state-of-the-art methods on the NUS dataset [25]. The compared methods include three traditional methods, Bundled [25], Robust L1 [5], Meshflow [22], and five deep learning based methods, DIFRINT [1], Yu et al. [41], PW-StableNet [43], DUT [36], and StabNet [33]. It is worth noting that Meshflow [22], StabNet [33], and ours are online, while the rest are offline. The results of the compared methods are obtained from publicly accessible implementations with default parameters or pre-trained models." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Quantitative results Table 1 presents the quantitative results for each of the five categories (including regular, quick rotation, zooming, crowd, and parallax), as well as the average results across all categories. From Table 1, we can see that offline approaches generally outperform online meth" + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "23035" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.104, + 0.096, + 0.305, + 0.177 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.306, + 0.096, + 0.492, + 0.177 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.493, + 0.096, + 0.675, + 0.177 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.678, + 0.096, + 0.862, + 0.177 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.104, + 0.178, + 0.305, + 0.258 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.306, + 0.178, + 0.492, + 0.258 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.493, + 0.178, + 0.676, + 0.258 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.678, + 0.178, + 0.864, + 0.258 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.104, + 0.259, + 0.305, + 0.339 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.306, + 0.259, + 0.492, + 0.339 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.493, + 0.259, + 0.676, + 0.339 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.678, + 0.259, + 0.864, + 0.339 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.104, + 0.34, + 0.305, + 0.419 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.306, + 0.34, + 0.492, + 0.419 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.493, + 0.34, + 0.676, + 0.419 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.678, + 0.34, + 0.864, + 0.419 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.104, + 0.42, + 0.305, + 0.5 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.306, + 0.421, + 0.492, + 0.5 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.493, + 0.42, + 0.676, + 0.501 + ], + "angle": 0, + "content": null + }, + { + "type": "image", + "bbox": [ + 0.678, + 0.421, + 0.864, + 0.501 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.178, + 0.505, + 0.249, + 0.516 + ], + "angle": 0, + "content": "(a) Meshflow" + }, + { + "type": "image_caption", + "bbox": [ + 0.368, + 0.505, + 0.429, + 0.516 + ], + "angle": 0, + "content": "(b) StabNet" + }, + { + "type": "image_caption", + "bbox": [ + 0.562, + 0.505, + 0.606, + 0.516 + ], + "angle": 0, + "content": "(c) Ours" + }, + { + "type": "image_caption", + "bbox": [ + 0.73, + 0.505, + 0.81, + 0.516 + ], + "angle": 0, + "content": "(d) Input frame" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.527, + 0.894, + 0.556 + ], + "angle": 0, + "content": "Figure 5. Qualitative comparisons with the online methods Meshflow [22] and StabNet [33]. We keep the original warped frames for comparison. The red boxes indicate the preserved frame content after cropping. The red arrows highlight the shear and distortion artifacts." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.574, + 0.47, + 0.68 + ], + "angle": 0, + "content": "ods, especially in challenging scenarios. In comparison to existing online approaches, our method achieves significant performance improvements. Taking Meshflow [22] as the baseline, the cropping ratio and the distortion value of our method increase by \\(17.25\\%\\) and \\(12.18\\%\\), respectively. Notably, our method can achieve approaching results to several compared offline methods." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.69, + 0.471, + 0.901 + ], + "angle": 0, + "content": "Qualitative results Fig. 5 illustrates the flaws that can be noticed directly from the video frames, including shear, distortion, and over-cropping. As can be seen, Meshflow suffers from shear and distortion in some scenes due to its reliance on well-optimized parameter tweaking. The shear and over-cropping problems in StabNet [33] are more severe because they directly employ video frames as input for mixed camera motion estimation and path smoothing, making the performance and generalization ability difficult to even approach the traditional approach Meshflow [22]. On the contrary, since our network solely smooths and optimizes the camera path, regardless of image content, it is more generic on diverse challenging scenes and can avoid the aforementioned issues in an online setting." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.574, + 0.892, + 0.74 + ], + "angle": 0, + "content": "User Study We also conduct a user study comparing our method to the PWStableNet [43], which is one of the deep offline approaches that achieves overall good performances according to Table 1. Note that we do not compare with the online methods [22, 33], because our qualitative results are significantly better than theirs. Specifically, we prepare a test set containing 15 videos (3 videos per category), and each of the 20 participants is asked to choose the better one from the results of the two compared methods. The videos are arranged randomly and the original unstable videos are provided. The results of the user study are shown in Fig. 7." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.754, + 0.665, + 0.769 + ], + "angle": 0, + "content": "4.3. Ablation Studies" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.779, + 0.892, + 0.809 + ], + "angle": 0, + "content": "To analyze the capability of each component, we conduct extensive ablation experiments on the NUS dataset [25]." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.811, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Ablation on losses We first conduct experiments on the motion-consistency loss, the shape-consistency loss, and the scale-preserving loss. In the first row of Table 2, we take the vanilla UNet optimized by the MC loss as our baseline. In the next two rows, we add the SC loss and the SP loss to train the model, respectively. Comparing the first three rows" + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.946, + 0.519, + 0.957 + ], + "angle": 0, + "content": "23036" + } + ], + [ + { + "type": "image", + "bbox": [ + 0.103, + 0.094, + 0.305, + 0.259 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.192, + 0.262, + 0.232, + 0.273 + ], + "angle": 0, + "content": "(a) MC" + }, + { + "type": "image", + "bbox": [ + 0.306, + 0.094, + 0.49, + 0.259 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.363, + 0.261, + 0.434, + 0.273 + ], + "angle": 0, + "content": "(b) \\(\\mathrm{MC} + \\mathrm{SC}\\)" + }, + { + "type": "image", + "bbox": [ + 0.492, + 0.094, + 0.679, + 0.259 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.537, + 0.261, + 0.634, + 0.273 + ], + "angle": 0, + "content": "(c) \\(\\mathrm{MC} + \\mathrm{SC} + \\mathrm{SP}\\)" + }, + { + "type": "image", + "bbox": [ + 0.68, + 0.095, + 0.867, + 0.259 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.732, + 0.261, + 0.813, + 0.273 + ], + "angle": 0, + "content": "(d) Input frame" + }, + { + "type": "image_caption", + "bbox": [ + 0.076, + 0.278, + 0.89, + 0.307 + ], + "angle": 0, + "content": "Figure 6. Qualitative results of the ablation study on the motion-consistency loss (MC), the shape-consistency loss (SC), and the scale-preserving loss (SP). The red arrows show the shear and distortion regions, and the red boxes show the preserved frame region." + }, + { + "type": "image", + "bbox": [ + 0.085, + 0.318, + 0.462, + 0.422 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.077, + 0.427, + 0.455, + 0.442 + ], + "angle": 0, + "content": "Figure 7. User study results comparing with PWStableNet [43]." + }, + { + "type": "table_caption", + "bbox": [ + 0.077, + 0.457, + 0.468, + 0.483 + ], + "angle": 0, + "content": "Table 2. Quantitative results of the ablation studies on the hybrid loss and the channel attention mechanism (CA)." + }, + { + "type": "table", + "bbox": [ + 0.089, + 0.483, + 0.458, + 0.556 + ], + "angle": 0, + "content": "
MCSCSPCACDS
Baseline✓0.800.840.87
Variant 1✓✓0.850.900.86
Variant 2✓✓✓0.900.950.86
Ours✓✓✓✓0.920.980.87
" + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.582, + 0.468, + 0.734 + ], + "angle": 0, + "content": "reveals that adding the SC loss and the SP loss respectively improves performance. The best performance is gained by combining them together. Fig. 6 shows some qualitative results. As seen, when only using the MC loss, substantial shear, and distortion occur (Fig. 6 (a), highlighted by red arrows.). The distortion artifacts can be effectively resolved by adding the SC loss (Fig. 6 (b)). However, the scale of the stabilized frame is not well preserved, resulting in larger cropped regions. This issue can eventually be solved by the proposed SP loss (Fig. 6 (c), distinguished by red boxes)." + }, + { + "type": "text", + "bbox": [ + 0.076, + 0.735, + 0.468, + 0.901 + ], + "angle": 0, + "content": "Analysis of the quality of the dataset To verify the impact of the dataset, we train the network on the DeepStab [33] and our MotionStab dataset, respectively. Fig. 8 shows the quantitative results on the NUS dataset. As seen, when trained using the proposed MotionStab dataset, both our method and StabNet [33] yield better results than training on the DeepStab dataset, respectively, especially in terms of cropping ratio and distortion value. We conclude that the main reasons are twofold. Firstly, our MotionStab dataset contains richer scenarios and unstable motions, improving the performance and generalization ability of the network." + }, + { + "type": "image", + "bbox": [ + 0.52, + 0.318, + 0.875, + 0.464 + ], + "angle": 0, + "content": null + }, + { + "type": "image_caption", + "bbox": [ + 0.5, + 0.47, + 0.89, + 0.497 + ], + "angle": 0, + "content": "Figure 8. Comparisons of the quantitative results between StabNet [33] and our method when trained with different datasets." + }, + { + "type": "text", + "bbox": [ + 0.499, + 0.511, + 0.892, + 0.603 + ], + "angle": 0, + "content": "Secondly, the synthesized pairs in MotionStab suffer no parallax issue inherent in DeepStab, leading to fewer distortion artifacts (i.e., higher distortion value) in the stabilized frames. Additionally, our method outperforms StabNet [33] on both datasets, demonstrating its superiority over directly predicting stable warp fields from input video frames." + }, + { + "type": "title", + "bbox": [ + 0.5, + 0.617, + 0.627, + 0.633 + ], + "angle": 0, + "content": "5. Conclusions" + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.643, + 0.892, + 0.825 + ], + "angle": 0, + "content": "This work presents a deep camera path optimization framework for online video stabilization. We leave the motion estimation to recent off-the-shelf deep motion models and concentrate on path smoothing. Our model takes a 2D camera path in a sliding window as input and outputs a warp field for the last frame in that window. A video can be stabilized online by applying our model repeatedly for every incoming frame. We introduce a hybrid loss to enhance the spatial and temporal consistency of the stabilized video. Moreover, we created a motion dataset to train our model. Results show that our method outperforms previous approaches both qualitatively and quantitatively." + }, + { + "type": "text", + "bbox": [ + 0.498, + 0.826, + 0.892, + 0.901 + ], + "angle": 0, + "content": "Acknowledgements This work was supported by Sichuan Science and Technology Program of China under grants Nos. 2023NSFSC0462, 2023NSFSC1972, 2022YFQ0079, 2021YFG0001, 2022YFG0050, and National Natural Science Foundation of China under grant No.62031009." + }, + { + "type": "page_number", + "bbox": [ + 0.479, + 0.945, + 0.518, + 0.957 + ], + "angle": 0, + "content": "23037" + } + ], + [ + { + "type": "title", + "bbox": [ + 0.08, + 0.09, + 0.175, + 0.107 + ], + "angle": 0, + "content": "References" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.116, + 0.47, + 0.157 + ], + "angle": 0, + "content": "[1] Jinsoo Choi and In So Kweon. Deep iterative frame interpolation for full-frame video stabilization. ACM Trans. on Graphics (TOG), 39(1):1-9, 2020. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.159, + 0.471, + 0.213 + ], + "angle": 0, + "content": "[2] Michael L Gleicher and Feng Liu. Re-cinematography: Improving the camerawork of casual video. ACM transactions on multimedia computing, communications, and applications (TOMM), 5(1):1-28, 2008. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.216, + 0.471, + 0.257 + ], + "angle": 0, + "content": "[3] Amit Goldstein and Raanan Fattal. Video stabilization using epipolar geometry. ACM Trans. on Graphics (TOG), 31(5):1-10, 2012. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.259, + 0.471, + 0.3 + ], + "angle": 0, + "content": "[4] Matthias Grundmann, Vivek Kwatra, Daniel Castro, and Irfan Essa. Calibration-free rolling shutter removal. In Proc. ICCP, pages 1-8, 2012. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.302, + 0.471, + 0.343 + ], + "angle": 0, + "content": "[5] Matthias Grundmann, Vivek Kwatra, and Irfan Essa. Autodirected video stabilization with robust 11 optimal camera paths. In Proc. CVPR, pages 225-232, 2011. 1, 2, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.345, + 0.471, + 0.399 + ], + "angle": 0, + "content": "[6] Wilko Guilluy, Laurent Oudre, and Azedine Beghdadi. Video stabilization: Overview, challenges and perspectives. Signal Processing: Image Communication, 90:116015, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.402, + 0.471, + 0.442 + ], + "angle": 0, + "content": "[7] Richard Hartley and Andrew Zisserman. Multiple view geometry in computer vision. Cambridge university press, 2003. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.445, + 0.471, + 0.5 + ], + "angle": 0, + "content": "[8] Mingbo Hong, Yuhang Lu, Nianjin Ye, Chunyu Lin, Qijun Zhao, and Shuaicheng Liu. Unsupervised homography estimation with coplanarity-aware gan. In Proc. CVPR, pages 17663-17672, 2022. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.087, + 0.502, + 0.471, + 0.529 + ], + "angle": 0, + "content": "[9] Jie Hu, Li Shen, and Gang Sun. Squeeze-and-excitation networks. In Proc. CVPR, pages 7132-7141, 2018. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.531, + 0.471, + 0.572 + ], + "angle": 0, + "content": "[10] Chia-Hung Huang, Hang Yin, Yu-Wing Tai, and Chi-Keung Tang. Stablenet: semi-online, multi-scale deep video stabilization. arXiv preprint arXiv:1907.10283, 2019. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.574, + 0.471, + 0.614 + ], + "angle": 0, + "content": "[11] Maria Silvia Ito and Ebroul Izquierdo. A dataset and evaluation framework for deep learning based video stabilization systems. In Proc. VCIP, pages 1-4. IEEE, 2019. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.617, + 0.471, + 0.672 + ], + "angle": 0, + "content": "[12] Dengchao Jin, Jianjun Lei, Bo Peng, Wanqing Li, Nam Ling, and Qingming Huang. Deep affine motion compensation network for inter prediction in vvc. IEEE Trans. on Circuits and Systems for Video Technology, 32(6):3923-3933, 2021. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.674, + 0.471, + 0.728 + ], + "angle": 0, + "content": "[13] Neel Joshi, Wolf Kienzle, Mike Toelle, Matt Uytendaele, and Michael F Cohen. Real-time hyperlapse creation via optimal frame selection. ACM Transactions on Graphics (TOG), 34(4):1-9, 2015. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.731, + 0.471, + 0.772 + ], + "angle": 0, + "content": "[14] Alexandre Karpenko, David Jacobs, Jongmin Baek, and Marc Levoy. Digital video stabilization and rolling shutter correction using gyroscopes. CSTR, 1(2):13, 2011. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.774, + 0.471, + 0.801 + ], + "angle": 0, + "content": "[15] Johannes Kopf. 360 video stabilization. ACM Transactions on Graphics (TOG), 35(6):1-9, 2016. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.803, + 0.471, + 0.844 + ], + "angle": 0, + "content": "[16] Ken-Yi Lee, Yung-Yu Chuang, Bing-Yu Chen, and Ming Ouhyoung. Video stabilization using robust feature trajectories. In Proc. CVPR, pages 1397-1404, 2009. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.846, + 0.471, + 0.901 + ], + "angle": 0, + "content": "[17] Yao-Chih Lee, Kuan-Wei Tseng, Yu-Ta Chen, Chien-Cheng Chen, Chu-Song Chen, and Yi-Ping Hung. 3d video stabilization with depth estimation by cnn-based optimization. In Proc. CVPR, pages 10621–10630, 2021. 1" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.116, + 0.471, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.134 + ], + "angle": 0, + "content": "[18] Feng Liu, Michael Gleicher, Hailin Jin, and Aseem Agarwala. Content-preserving warps for 3d video stabilization. ACM Trans. on Graphics (ToG), 28(3):1-9, 2009. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.137, + 0.892, + 0.177 + ], + "angle": 0, + "content": "[19] Feng Liu, Michael Gleicher, Jue Wang, Hailin Jin, and Aseem Agarwala. Subspace video stabilization. ACM Trans. on Graphics (TOG), 30(1):1-10, 2011. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.179, + 0.892, + 0.233 + ], + "angle": 0, + "content": "[20] Shuaicheng Liu, Mingyu Li, Shuyuan Zhu, and Bing Zeng. Codingflow: Enable video coding for video stabilization. IEEE Trans. on Image Processing, 26(7):3291-3302, 2017. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.235, + 0.892, + 0.302 + ], + "angle": 0, + "content": "[21] Shuaicheng Liu, Yuhang Lu, Hai Jiang, Nianjin Ye, Chuan Wang, and Bing Zeng. Unsupervised global and local homography estimation with motion basis learning. IEEE Trans. on Pattern Analysis and Machine Intelligence, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.304, + 0.892, + 0.347 + ], + "angle": 0, + "content": "[22] Shuaicheng Liu, Ping Tan, Lu Yuan, Jian Sun, and Bing Zeng. Meshflow: Minimum latency online video stabilization. In Proc. ECCV, pages 800-815, 2016. 1, 2, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.349, + 0.892, + 0.389 + ], + "angle": 0, + "content": "[23] Shuaicheng Liu, Yinting Wang, Lu Yuan, Jiajun Bu, Ping Tan, and Jian Sun. Video stabilization with a depth camera. In Proc. CVPR, pages 89-95, 2012. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.391, + 0.892, + 0.445 + ], + "angle": 0, + "content": "[24] Shuaicheng Liu, Nianjin Ye, Chuan Wang, Kunming Luo, Jue Wang, and Jian Sun. Content-aware unsupervised deep homography estimation and beyond. IEEE Trans. on Pattern Analysis and Machine Intelligence, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.447, + 0.892, + 0.489 + ], + "angle": 0, + "content": "[25] Shuaicheng Liu, Lu Yuan, Ping Tan, and Jian Sun. Bundled camera paths for video stabilization. ACM Trans. on Graphics (TOG), 32(4):1-10, 2013. 1, 2, 3, 6, 7" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.49, + 0.892, + 0.532 + ], + "angle": 0, + "content": "[26] Shuaicheng Liu, Lu Yuan, Ping Tan, and Jian Sun. Steadyflow: Spatially smooth optical flow for video stabilization. In Proc. CVPR, pages 4209-4216, 2014. 1, 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.533, + 0.892, + 0.588 + ], + "angle": 0, + "content": "[27] Yasuyuki Matsushita, Eyal Ofek, Weina Ge, Xiaou Tang, and Heung-Yeung Shum. Full-frame video stabilization with motion inpainting. IEEE Trans. on Pattern Analysis and Machine Intelligence, 28(7):1150-1163, 2006. 1, 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.59, + 0.892, + 0.645 + ], + "angle": 0, + "content": "[28] Lang Nie, Chunyu Lin, Kang Liao, Shuaicheng Liu, and Yao Zhao. Depth-aware multi-grid deep homography estimation with contextual correlation. IEEE Trans. on Circuits and Systems for Video Technology, 32(7):4460-4472, 2022. 1" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.647, + 0.892, + 0.687 + ], + "angle": 0, + "content": "[29] Hui Qu, Li Song, and Gengjian Xue. Shaking video synthesis for video stabilization performance assessment. In Proc. VCIP, pages 1-6. IEEE, 2013. 4" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.689, + 0.892, + 0.73 + ], + "angle": 0, + "content": "[30] Ethan Rublee, Vincent Rabaud, Kurt Konolige, and Gary Bradski. Orb: An efficient alternative to sift or surf. In Proc. ICCV, pages 2564-2571, 2011. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.732, + 0.892, + 0.759 + ], + "angle": 0, + "content": "[31] Jianbo Shi et al. Good features to track. In Proc. CVPR, pages 593-600, 1994. 2" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.761, + 0.892, + 0.801 + ], + "angle": 0, + "content": "[32] Brandon M Smith, Li Zhang, Hailin Jin, and Aseem Agarwala. Light field video stabilization. In Proc. ICCV, pages 341-348, 2009. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.803, + 0.892, + 0.871 + ], + "angle": 0, + "content": "[33] Miao Wang, Guo-Ye Yang, Jin-Kun Lin, Song-Hai Zhang, Ariel Shamir, Shao-Ping Lu, and Shi-Min Hu. Deep online video stabilization with multi-grid warping transformation learning. IEEE Trans. on Image Processing, 28(5):2283-2292, 2018. 1, 2, 3, 4, 5, 6, 7, 8" + }, + { + "type": "ref_text", + "bbox": [ + 0.503, + 0.873, + 0.892, + 0.901 + ], + "angle": 0, + "content": "[34] Yu-Shuen Wang, Feng Liu, Pu-Sheng Hsu, and Tong-Yee Lee. Spatially and temporally optimized video stabiliza" + }, + { + "type": "list", + "bbox": [ + 0.503, + 0.093, + 0.892, + 0.901 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.945, + 0.52, + 0.957 + ], + "angle": 0, + "content": "23038" + } + ], + [ + { + "type": "ref_text", + "bbox": [ + 0.11, + 0.092, + 0.468, + 0.12 + ], + "angle": 0, + "content": "tion. IEEE Trans. on Visualization and Computer Graphics, 19(8):1354-1361, 2013. 2, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.122, + 0.469, + 0.176 + ], + "angle": 0, + "content": "[35] Sen-Zhe Xu, Jun Hu, Miao Wang, Tai-Jiang Mu, and ShiMin Hu. Deep video stabilization using adversarial networks. In Computer Graphics Forum, volume 37, pages 267-276, 2018. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.179, + 0.469, + 0.233 + ], + "angle": 0, + "content": "[36] Yufei Xu, Jing Zhang, Stephen J Maybank, and Dacheng Tao. Dut: Learning video stabilization by simply watching unstable videos. IEEE Trans. on Image Processing, 31:4306-4320, 2022. 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.235, + 0.469, + 0.276 + ], + "angle": 0, + "content": "[37] Junlan Yang, Dan Schonfeld, Chong Chen, and Magdi Mohamed. Online video stabilization based on particle filters. In Proc. ICIP, pages 1545-1548, 2006. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.278, + 0.469, + 0.332 + ], + "angle": 0, + "content": "[38] Nianjin Ye, Chuan Wang, Haoqiang Fan, and Shuaicheng Liu. Motion basis learning for unsupervised deep homography estimation with subspace projection. In Proc. ICCV, pages 13117-13125, October 2021. 1, 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.334, + 0.469, + 0.389 + ], + "angle": 0, + "content": "[39] Nianjin Ye, Chuan Wang, Shuaicheng Liu, Lanpeng Jia, Jue Wang, and Yongqing Cui. Deepmeshflow: Content adaptive mesh deformation for robust image registration. arXiv preprint arXiv:1912.05131, 2019. 1, 2, 3, 4, 5" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.391, + 0.469, + 0.432 + ], + "angle": 0, + "content": "[40] Jiyang Yu and Ravi Ramamoorthi. Robust video stabilization by optimization in cnn weight space. In Proc. CVPR, pages 3800-3808, 2019. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.434, + 0.469, + 0.474 + ], + "angle": 0, + "content": "[41] Jiyang Yu and Ravi Ramamoorthi. Learning video stabilization using optical flow. In Proc. CVPR, pages 8159-8167, 2020. 1, 3, 6" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.477, + 0.468, + 0.517 + ], + "angle": 0, + "content": "[42] Jiyang Yu, Ravi Ramamoorthi, Keli Cheng, Michel Sarkis, and Ning Bi. Real-time selfie video stabilization. In Proc. CVPR, pages 12036-12044, 2021. 3" + }, + { + "type": "ref_text", + "bbox": [ + 0.08, + 0.519, + 0.469, + 0.561 + ], + "angle": 0, + "content": "[43] Minda Zhao and Qiang Ling. Pwstablenet: Learning pixelwise warping maps for video stabilization. IEEE Trans. on Image Processing, 29:3582-3595, 2020. 6, 7, 8" + }, + { + "type": "list", + "bbox": [ + 0.08, + 0.092, + 0.469, + 0.561 + ], + "angle": 0, + "content": null + }, + { + "type": "page_number", + "bbox": [ + 0.48, + 0.945, + 0.519, + 0.957 + ], + "angle": 0, + "content": "23039" + } + ] +] \ No newline at end of file diff --git a/2023/Minimum Latency Deep Online Video Stabilization/5c08d8de-7fcf-430c-a7d0-16aae326aed4_origin.pdf b/2023/Minimum Latency Deep Online Video Stabilization/5c08d8de-7fcf-430c-a7d0-16aae326aed4_origin.pdf new file mode 100644 index 0000000000000000000000000000000000000000..38ea663f3d26db5c6801eba51072f1a1b1b63401 --- /dev/null +++ b/2023/Minimum Latency Deep Online Video Stabilization/5c08d8de-7fcf-430c-a7d0-16aae326aed4_origin.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:eb5e0f71852a6562f4bae462b57c2e3a117d4b0233d7383e0ed1b4543f23a5bb +size 2818976 diff --git a/2023/Minimum Latency Deep Online Video Stabilization/full.md b/2023/Minimum Latency Deep Online Video Stabilization/full.md new file mode 100644 index 0000000000000000000000000000000000000000..4c72bf4933676545c652cf725307d1c30ceb3807 --- /dev/null +++ b/2023/Minimum Latency Deep Online Video Stabilization/full.md @@ -0,0 +1,376 @@ +# Minimum Latency Deep Online Video Stabilization + +Zhuofan Zhang $^{1*}$ Zhen Liu $^{2*}$ Ping Tan $^{3}$ Bing Zeng $^{1}$ Shuaicheng Liu $^{1,2\dagger}$ $^{1}$ University of Electronic Science and Technology of China $^{2}$ Megvii Technology + $^{3}$ The Hong Kong University of Science and Technology + +{zhangzf98@std., eezeng@, liushuaicheng@}uestc.edu.cn, liuzhen03@megvii.com, pingtan@ust.hk + +# Abstract + +We present a novel camera path optimization framework for the task of online video stabilization. Typically, a stabilization pipeline consists of three steps: motion estimating, path smoothing, and novel view rendering. Most previous methods concentrate on motion estimation, proposing various global or local motion models. In contrast, path optimization receives relatively less attention, especially in the important online setting, where no future frames are available. In this work, we adopt recent off-the-shelf high-quality deep motion models for motion estimation to recover the camera trajectory and focus on the latter two steps. Our network takes a short 2D camera path in a sliding window as input and outputs the stabilizing warp field of the last frame in the window, which warps the coming frame to its stabilized position. A hybrid loss is well-defined to constrain the spatial and temporal consistency. In addition, we build a motion dataset that contains stable and unstable motion pairs for the training. Extensive experiments demonstrate that our approach significantly outperforms state-of-the-art online methods both qualitatively and quantitatively and achieves comparable performance to offline methods. Our code and dataset are available at https://github.com/1iuzhen03/NNDVS. + +# 1. Introduction + +Video stabilization methods aim at removing unwanted shaky motions of a video caused by unsteady moving capture [6]. Traditional methods often take three main steps: 1) camera motion estimating for trajectory recovery; 2) camera path smoothing; and 3) steady frame synthesis. According to the adopted motion model in the first step, these methods can be broadly classified as 2D or 3D. 2D methods adopt planar motion models such as affine [5], or homog- + +![](images/449348ad10987f8b6c931b47b383dd675705882a671aed3ada8357c1b4715c65.jpg) +(a) Illustration of the dataset synthesis process. + +![](images/4bc2f3f7163e496eb982983f88e49cc3d493363aa8aa460c044ffc6b8ce04316.jpg) +(b) Illustration of the synthesized camera path. + +![](images/05e2eb8628669596f644c9ca8a5c3774a1d3dbdd856941d93dff85b9647f9281.jpg) +Figure 1. Illustration of the dataset synthesis process (a) and the synthesized camera path (b). We transfer an unstable path to a stable path, creating a synthesized path, which shares high frequencies of the unstable path with low frequencies of the stable path. + +raphy [27], or mesh [25, 22, 33], or flow [26, 20, 41], while 3D methods resort to 3D depth [23, 17], or reconstructed points [18], or epipolar geometry constraints [3]. + +In comparison, deep learning-based methods learn stabilization models from stable and unstable video pairs [33, 41, 35] without explicit steps of motion estimation and smoothing. However, the results of deep methods are often visually inferior to those of traditional ones. A potential reason is that these methods try to learn the three steps all in a unified framework, each of which has different characteristics but is learned in the network blindly. + +On the other hand, deep affine [12], deep homography [38, 8], and deep mesh models [39, 24, 21, 28] have demonstrated high-quality image registration, even under adverse cases. They are robust to scenes with large depth variation, large dynamic objects, and poor textures, fitting perfectly for the camera motion estimation. In this work, we argue that it is not necessary to enclose all three steps of the stabilization into the learning pipeline, but let the motion estimation to the recent deep motion models [39, 24]. + +In this way, our network only focuses on learning to stabilize the shaky camera motion, which makes the learning process much more efficient and effective. + +Camera path smoothing can be performed offline or online, where the former optimizes the path globally while the latter smooths the path on-the-fly. In other words, offline approaches have access to all past and future frames during optimization, as it often stabilizes a video after it is captured. In contrast, online methods aim to stabilize a video during the capture. Note that, the concept of real-time differs from that of online, as an online method must be in real-time whereas an offline method can run at real-time speed. The main distinction is the availability of future frames. + +Most existing methods are offline [25, 5, 4, 34, 26]. However, the online setting is critical as many applications desire instant visual feedback based on live video streams [22, 33]. Normally, with limited or even no access to future frames, online methods cannot achieve equal stability as offline methods, particularly in the suppression of the low-frequency camera shake, which frequently necessitates a long camera path. One may argue that online methods can have all the past frames for processing. However, future motions are important, if not more important than the past. Because, for one thing, fast camera motions can happen at any time suddenly, e.g., quick rotation or zooming. The reaction time is short. Inappropriate processing may either decrease the stability or create artifacts such as excessive cropping. For another, all the past frames have already been shown to the audience, meaning that they are fixed, and thus cannot be modified. We can only adjust the unstabled future frames to the frozen past ones. + +To this end, we propose a deep online camera path smooth network that takes a pre-estimated short 2D camera trajectory in a sliding window as input and outputs the motion compensation warp field of the last frame in the window for the stabilized view, which is the setting of online stabilization with the minimum latency. A video can be stabilized on the fly by applying our model repeatedly for every incoming frame. To deal with depth changes and moving objects, we employ the mesh-based motion model [39] which demonstrates excellent robustness in various scenes. Instead of directly inputting the mesh structure or mesh cells as local homographies to the network, we convert the estimated motion to a dense flow field, which can be fed into the convolutional neural network naturally. We show that it is a more convenient representation compared to other alternatives, e.g., vertex sparse motion vectors or homography matrix, which cannot be easily adapted as input to CNNs. Based on that, we further propose a hybrid loss, which consists of the motion-consistency loss, the shape-consistency loss, and the scale-preserving loss, to maintain the spatial coherence and temporal continuity of the stabilized video. + +Besides, we create a motion dataset, MotionStab, to + +train our network. In particular, we capture 110 stable videos with a cell phone mounted on a hand-held physical stabilizer. Then, we create a shaky video by transforming each frame of the stable video according to the motion of another irrelevant shaky video. In this way, the stable and unstable motion pairs can be constructed. Fig. 1 shows our idea. Note that, our dataset is different from DeepStab [33], which is captured by a stable and a shaky camera simultaneously. We directly transfer the motion of a shaky video to a stable video. The contents of the two videos are not important but the motion does. That means DeepStab [33] offers frame pairs, while our MotionStab offers motion pairs. We feed the motions to the network instead of RGB frames. + +The benefits are three folds: 1) image contents are diverse, while motion mappings are much easier to learn; 2) motion as mesh is lightweight, so does the network; 3) the network can be more focused by excluding the task of the motion estimation. As a result, we show that this motion learning pipeline is effective enough, such that it can work with straightforward network architectures, e.g., UNet, without help from more advanced designs or sophisticated modules. Complex motion types can be learned by the network successfully, as long as they exist in the training data. As such, the network can be kept simple yet effective. + +In summary, the main contributions of this paper are concluded as follows: + +- We propose a novel deep camera path optimization framework for online video stabilization. +- We propose a hybrid loss to enable robust supervision for maintaining the spatial and temporal coherence of the stabilized video. +- We build a comprehensive MotionStab dataset that covers various motions for camera path optimization. +- We conduct extensive experiments to demonstrate the effectiveness of the proposed approach against existing state-of-the-art online and offline methods. + +# 2. Related Works + +# 2.1. Traditional Methods + +Early 2D approaches track image features for several frames and then smooth these feature trajectories to stabilize a video [16, 34]. However, long feature tracks [31] are hard to be obtained when large camera motions exist. Later, motion models, such as affine [5] or homography [27, 2], are calculated between neighboring frames, relaxing the requirement of long feature tracks into feature matches [30] between adjacent frames. Then, these motion models are accumulated to generate a 2D camera trajectory, which is shown to be a good replacement against + +track-based approaches, owning largely improved robustness. With respect to the motion representation, homography mixture [4], mesh [25, 22, 34], and optical flow [26, 20] based motion models are proposed to deal with scenes that contain large depth variations. Besides, some approaches focus on special stabilization tasks, such as Selfie [42], 360 [15], and hyperlapse videos [13]. + +On the other hand, 3D-based methods require 3D camera motions or scene structure for stabilization. The 3D structure can either be calculated from the video by structure-from-motion (SfM) [18] or acquired from additional hardware, such as a depth camera [23], a gyroscope sensor [14], or a light field camera [32]. However, full 3D stabilization is fragile and computationally expensive [18]. Partial 3D methods proposed 3D constraints, such as subspace projection [19] and epipolar geometry [3], to alleviate the requirement of full 3D reconstruction [7]. Normally, 3D methods can better handle the scene parallax compared with 2D approaches due to the physical correctness, as long as the 3D information can be available. + +# 2.2. Deep Learning Methods + +Deep methods take the video frames as input and directly output the stabilized frames, which are often trained with stable and unstable frame pairs acquired by special hardware, e.g., DeepStab dataset [33]. Xu et al. used the adversarial network to generate a target image to guide the warping [35]. Yu et al. learned the flow fields from initial optical flow estimation for the accurate per-pixel motion compensation [41]. Deep methods suffer from the generalization problem, given that DeepStab only contains 60 videos. Yu et al. used the CNN as the optimizer instead of learning from data to overfit each input example [40]. + +Recently, deep motion models have achieved good results for motion estimation, such as deep homography [38, 8] and deep meshflow [39], which is more robust in adverse cases compared to traditional solutions, such as scenes of low texture and low light. In this work, we adopt the deep meshflow [39] for our camera motion estimator and design a network concentrating on camera path smoothing. + +# 2.3. Online Approaches + +Most of the video stabilization approaches are offline, where a video is processed after it has been captured. Online methods stabilize a video during the capture [37, 33, 22]. One may argue that global path optimization can be easily modified to online methods by applying a sliding window scheme. However, the stability would inevitably decrease, let alone the existence of challenging camera motions, such as quick rotation and zooming, which may introduce artifacts such as wobble and excessive cropping. Previously, these difficult motions can only be solved satisfactorily by global camera path smoothing. In this work, + +we propose to solve these problems with our proposed deep online camera path optimization framework. + +# 3. Methodology + +# 3.1. Problem Formulation + +Our method is built upon convolutional neural networks. As illustrated in Fig. 3 (a), given an incoming unsteady frame $I_{t}$ at timestamp $t$ , our deep online video stabilization aims to predict the corresponding steady frame $I_{t}^{\prime}$ with no future frames. Here, we use “/” to represent predicted quantities. Note that, previous learning-based methods learn the mapping $f(\cdot)$ from the input shaky RGB frames and predict a warp field $B_{t}^{\prime}$ of frame $I_{t}$ , which can be formulated as + +$$ +\left\{B _ {t} ^ {\prime} \right\} = f \left(\left\{I _ {t} \right\}\right), \tag {1} +$$ + +where $\{\cdot\}$ represents a set of elements. However, our experiments show that directly using complex RGB video frames as input and mixing motion estimation and path smoothing in a network frequently causes estimation errors, resulting in wobbling and distortion artifacts. + +In this work, we propose our approach from a novel perspective, where we separate the motion estimation step from the network alone and leave the network focus on camera path smoothing. Specifically, we consider using a fixed window of $r$ past frames $\{I_t\}_r = \langle I_{t - r},\dots,I_{t - 1},I_t\rangle$ of minimum latency (i.e. without using future frames) to stabilize the incoming target frame $I_{t}$ . The camera motion $\{F_t\}$ is estimated by an off-the-shelf deep motion estimation model. Our camera path smooth network uses only the estimated motion as input to predict the corresponding warp field $B_t'$ , i.e., + +$$ +\left\{B _ {t} ^ {\prime} \right\} = \Phi \left(\left\{F _ {t} \right\}; \theta\right), \tag {2} +$$ + +where $\Phi(\cdot)$ denotes the camera path smoothing network and $\theta$ is the network parameters to be optimized. We empirically set $r$ to 15 in our experiments. + +# 3.2. Deep Online Camera Path Optimization + +As shown in Fig. 2, the overall pipeline of the proposed deep online camera path optimization framework mainly consists of three stages. Firstly, we adopt a deep motion extraction model for robust camera motion estimation. Secondly, the camera path smooth network takes the unsteady camera motion as input and predicts the smoothed warp field. Finally, the original shaky frame is transformed by the predicted warp field to synthesize the target steady frame. + +Camera Motion Estimation The first step is to estimate the camera motion. We employ an optimized deep mesh-flow model [39] to extract the inter-frame motion. Specifically, given the incoming frame $I_{t}$ and past adjacent frame + +![](images/bc01b6585b98bd47570dab0021445423a4c5d6485ca18a1476aee7a6f2f5b394.jpg) +Figure 2. The overall pipeline of the proposed deep online camera path optimization framework. (a) We first employ a deep motion extraction model to estimate the unsteady camera motion. (b) Then, the estimated motion is fed into the camera path smooth network, yielding the smoothed warp field. (c) Finally, the target steady frame is synthesized by the predicted smooth warp field. + +![](images/e154d9df9a963fc93899e9f318b36fb40dcb138ce76f8fb5f182457357377c1e.jpg) +(a) + +![](images/993bf0d2ef9444d76e7503ff2ec5b357403a89a63584c45007cf0123625be8a5.jpg) +(b) +Figure 3. Relationships between the unstable/synthesized video and the stable video. (a) depicts the basic relationships of the unstable video $\{I_t\}$ and stabilized video $\{I_t'\}$ , and (b) illustrates the main idea of our dataset synthesis strategy that transfers collected unstable motions $\{F_t^{\mathrm{ust}}\}$ to stable video frames $\{I_t^{\mathrm{stb}}\}$ , generating synthesized unstable video frames $\{I_t^{\mathrm{syn}}\}$ . + +$I_{t - 1}$ with size of $640\times 360$ we estimate $F_{t}$ by model [39] (Fig. 3 (a), upper yellow part). Repeat this process, we accumulate a set of inter-frame motions, $\{F_t\}_{r - 1} = \langle F_{t - r + 1},\dots ,F_{t - 1},F_t\rangle$ . In particular, we keep the most recent $r - 1$ motions in our buffer, where historical motions that are beyond range $r - 1$ are simply dropped. The deep meshflow motion estimation is defined as: + +$$ +F _ {t} = \downarrow_ {s} \mathcal {M} _ {F} \left(I _ {t}, I _ {t - 1}\right), \tag {3} +$$ + +where $\mathcal{M}_F(\cdot)$ is the pre-trained deep meshflow model. $\downarrow_{s}$ indicates that we collect the sparse motions at the mesh vertexes, and shrink them pixel by pixel to form a downsampled dense motion field, for the purpose of feeding it to the CNNs. The scale factor $s$ is set to 8, and the size of the dense motion field $F_{t}$ is $80\times 45$ . + +Camera Path Smooth Network Given the estimated camera motion $\{F_t\}_{r - 1}$ as input, the camera path smooth net + +work predicts the target smoothed warp field $B_{t}^{\prime}$ as Eq. 2. Note that, the meshflow model is spatially-variant, and so does the $F_{t}$ . Therefore, we provide spatial and temporal optimizations. The camera path smooth network is designed as an encoder-decoder architecture and we implement it as a 4-stage UNet with channels of 64, 128, 256, and 512. We further employ the channel attention mechanism (CA) [9] to adaptively learn the weights of different historical motions. + +Steady Frame Rendering After obtaining the warp field $B_{t}^{\prime}$ , we inverse the process of shrinking, where we put the motions back to the sparse vertex locations to create a mesh, based on which we warp the shaky frame $I_{t}$ to its stabilized position $I_{t}^{\prime}$ : + +$$ +I _ {t} ^ {\prime} = \mathcal {W} \left(I _ {t}, B _ {t} ^ {\prime}\right), \tag {4} +$$ + +where $\mathcal{W}(\cdot)$ denotes the backward warping function. The first parameter is an image and the second is a warp field. + +# 3.3. Training Dataset + +Existing training datasets are either captured simultaneously by two cameras [33] or synthesized by simulated injected noise [10, 29, 11]. The former would naturally suffer from parallax problems, while the latter makes the synthesized video paths unrealistic. To address this issue, we offer a novel synthetic method that can build realistic unstable/stable motion pairs from existing shaky videos. + +Our main idea is to transfer the motion of an unstable shaky video $V_{\mathrm{ust}}$ to a stable video $V_{\mathrm{stb}}$ , yielding another synthesized shaky video $V_{\mathrm{syn}}$ with motions from $V_{\mathrm{ust}}$ but image contents as $V_{\mathrm{stb}}$ . The videos $V_{\mathrm{ust}}$ and $V_{\mathrm{stb}}$ are irrelevant. Let's denote $\{I_t^{\mathrm{ust}}\}$ , $\{I_t^{\mathrm{stb}}\}$ , $\{I_t^{\mathrm{syn}}\}$ as video frames and + +$\{F_t^{\mathrm{ust}}\} ,\{F_t^{\mathrm{stb}}\} ,\{F_t^{\mathrm{syn}}\}$ as motion between frames of video $\mathbf{V}_{\mathrm{ust}},\mathbf{V}_{\mathrm{stb}},\mathbf{V}_{\mathrm{syn}}$ accordingly. + +To achieve this, we first estimate the motions $\{F_t^{\mathrm{ust}}\}$ , $\{F_t^{\mathrm{stb}}\}$ between adjacent frames of $V_{\mathrm{ust}}$ and $V_{\mathrm{stb}}$ by deep meshflow [39]. Next, we warp the frame $\{I_t^{\mathrm{stb}}\}$ by motion $\{F_t^{\mathrm{ust}}\}$ to produce $\{I_t^{\mathrm{syn}}\}$ , for each timestamp $t$ : + +$$ +I _ {t} ^ {\text {s y n}} = \mathcal {W} \left(I _ {t} ^ {\text {s t b}}, F _ {t} ^ {\text {u s t}}\right). \tag {5} +$$ + +Applying Eq. 5 to every frame of $V_{\mathrm{stb}}$ creates the desired $V_{\mathrm{syn}}$ . The $V_{\mathrm{stb}}$ and $V_{\mathrm{syn}}$ become a pair of stable/unstable videos, where the following motion equality holds (Please refer to Fig. 3 (b) for the relation), for each timestamp $t$ : + +$$ +F _ {t} ^ {\text {u s t}} + F _ {t} ^ {\text {s y n}} = F _ {t} ^ {\text {s t b}} + F _ {t - 1} ^ {\text {u s t}}, \tag {6} +$$ + +where $F_{t}^{\mathrm{ust}}$ , $F_{t}^{\mathrm{stb}}$ have been calculated which are known. Therefore, $F_{t}^{\mathrm{syn}}$ can be calculated as: + +$$ +F _ {t} ^ {\text {s y n}} = F _ {t} ^ {\text {s t b}} + F _ {t - 1} ^ {\text {u s t}} - F _ {t} ^ {\text {u s t}}. \tag {7} +$$ + +During the training, our network takes a subset of motions $\{F_t^{\mathrm{syn}}\}_{r - 1} = \langle F_{t - r + 1}^{\mathrm{syn}},\dots ,F_{t - 1}^{\mathrm{syn}},F_t^{\mathrm{syn}}\rangle$ as input and output a motion field that is as close as the ground-truth label $-F_{t}^{\mathrm{ust}}$ , which is the inverse motion of $F_{t}^{\mathrm{ust}}$ as shown in Fig. 3 (b). On the other hand, the generated videos $V_{\mathrm{stb}}$ and $V_{\mathrm{syn}}$ are not important, as all we need are motions that can be calculated and derived by relations. + +To further establish the training dataset, we collected 110 stable videos of five categories (including regular, rotation, zooming, parallax, and crowd) using a cell phone mounted on a hand-held physical stabilizer. Next, we collected over 150 unstable videos from the website. Subsequently, we performed data synthesis on the collected stable and unstable videos by employing the aforementioned method, constructing the MotionStab dataset, which contains paired unstable/stable camera motion of various complex scenarios. As illustrated in Fig. 1 (b), the camera path of the synthesized video pairs is well-registered and realistic as the original unstable one. + +# 3.4. Training Loss + +To train the camera path smooth network, we define several losses in our framework: the motion-consistency loss for maintaining motion continuity between consecutive frames, the shape-consistency loss for preserving the geometry of the predicted warp field, and the scale-preserving loss for maintaining the scale of the predicted warp field. + +Motion-consistency Loss To keep the continuity of the predicted consecutive video frames, the inter-frame motion of the stabilized video $F_{t}^{\prime}$ should be as similar as the ground truth one $\hat{F}_{t}$ , i.e., + +$$ +\mathcal {L} _ {\mathrm {M C}} = \left\| F _ {t} ^ {\prime} - \hat {F} _ {t} \right\| _ {1}. \tag {8} +$$ + +![](images/ccab14db126c57c99f19b50482e43e9ef3f584284a2bcb2dd441266bdb5645c7.jpg) +(a) original meshgrid + +![](images/0dacd8306a21dc7955c540c2d9e5ce04a38030ed242a14520c6b1128ef5d50dd.jpg) +(b) transformed meshgrid +Figure 4. Illustration of the shape-consistency loss and the scale-preserving loss. The shape-consistency loss is employed to preserve the geometry shape of a meshgrid and the scale-preserving loss is used to maintain the scale. + +According to the relationship of Fig. 3 (a), Eq. 8 can be written as + +$$ +\begin{array}{l} \mathcal {L} _ {\mathrm {M C}} = \left\| \left(F _ {t} + B _ {t - 1} ^ {\prime} - B _ {t} ^ {\prime}\right) - \left(F _ {t} + \hat {B} _ {t - 1} - \hat {B} _ {t}\right) \right\| _ {1} (9) \\ = \left\| B _ {t - 1} ^ {\prime} - B _ {t} ^ {\prime} - \hat {B} _ {t - 1} + \hat {B} _ {t} \right\| _ {1}, (10) \\ \end{array} +$$ + +where $B_{t}^{\prime}$ denotes network output of the predicted warp field. That is to say, the motion continuity can be restrained by the ground truth warp field $\hat{B}_{t}$ and $\hat{B}_{t - 1}$ . + +Shape-consistency Loss The shape-consistency loss is effective to prevent the distortion problem of the predicted warp field. Following Wang et al. [33], we implement the SC loss as an intra-grid loss term and an inter-grid loss term: + +$$ +\mathcal {L} _ {\mathrm {S C}} = \mathcal {L} _ {\text {i n t r a}} + \mathcal {L} _ {\text {i n t e r}}. \tag {11} +$$ + +Note that each pixel of our dense warp field is actually a vertex of the mesh grid. As depicted in Fig. 4, the intra-grid loss term is defined as: + +$$ +\mathcal {L} _ {\text {i n t r a}} = \frac {1}{N} \sum_ {v _ {i}} \left\| \left(v _ {i} ^ {1} - v _ {i}\right) \cdot \left(v _ {i} ^ {2} - v _ {i}\right) \right\| _ {1}, \tag {12} +$$ + +where $i$ denotes the $i$ -th vertex and $N$ is the total number of vertices. Besides, the inter-grid loss term is used to maintain the geometric consistency of adjacent grids: + +$$ +\mathcal {L} _ {\text {i n t e r}} = \frac {1}{N} \sum_ {v _ {i}} \left\| \left(v _ {i} ^ {1} - v _ {i}\right) - \left(v _ {i} - v _ {i} ^ {3}\right) \right\| _ {1}. \tag {13} +$$ + +Scale-preserving Loss Since we convert the sparse motions at the mesh vertexes as a dense motion field and predict the mesh warp field, we introduce a scale-preserving loss to maintain the scale consistency of the predicted warp field: + +$$ +\mathcal {L} _ {\mathrm {S P}} = \frac {1}{N} \sum_ {v _ {i}} \left\| \frac {\left\| v _ {i} ^ {1} - v _ {i} \right\| _ {2}}{s} - 1 \right\| _ {1}. \tag {14} +$$ + +Table 1. Quantitative comparisons on the NUS dataset [25]. We use the Cropping ratio (C), the Distortion value (D), and the Stability score (S) as evaluation metrics. All of these metrics are in the range of 0 to 1, and the higher the better. The $*$ denotes the results of Bundled [25] are computed directly from the NUS dataset. The bests are marked in red and the second bests are in blue. + +
MethodsRegularRotationZooming
CDSCDSCDS
Offline* Bundled [25]0.66580.94090.90480.64770.86920.91940.57730.90730.9236
Robust L1 [5]0.71570.92520.84540.72060.82310.86170.71070.83290.7730
DIFRINT [1]0.98540.95550.81770.94130.88130.87010.95280.85310.8763
Yu et al. [41]0.94860.97520.84270.76610.76160.93170.89710.86300.9107
PWStableNet [43]0.93190.98520.81620.88010.97070.92510.93030.97920.8906
DUT [36]0.94850.96000.87170.76090.69400.92030.89860.86060.9221
OnlineMeshflow [22]0.80810.91680.83860.75780.76790.90920.77730.87150.8839
StabNet [33]0.74910.83930.84060.74170.72050.83840.73760.78070.8697
Ours0.94330.99170.80300.90210.98470.93410.91850.97360.8982
MethodsCrowdParallaxAvg.
CDSCDSCDS
Offline* Bundled [25]0.66850.89100.87440.71580.89650.89640.65500.90100.9037
Robust L1 [5]0.72080.90770.85040.71320.80540.87780.71620.85890.8417
DIFRINT [1]0.96620.87130.84560.97460.88230.86000.96410.88870.8539
Yu et al. [41]0.90810.91910.86600.92090.92190.88960.88820.88720.8881
PWStableNet [43]0.91810.97900.81620.92440.98020.85490.91700.97890.8606
DUT [36]0.89860.86170.90420.92540.87740.91270.88600.85070.9062
OnlineMeshflow [22]0.78880.82460.82800.81210.84290.84880.78820.87620.8617
StabNet [33]0.72470.77250.79120.69670.76600.82890.72800.77580.8338
Ours0.92470.98160.84080.93260.98270.87620.92420.98290.8705
+ +where $s$ is the scale factor in Eq. 3. Eventually, the overall loss is the combination of the above three loss terms: + +$$ +\mathcal {L} = \mathcal {L} _ {\mathrm {M C}} + \alpha \mathcal {L} _ {\mathrm {S C}} + \beta \mathcal {L} _ {\mathrm {S P}}, \tag {15} +$$ + +where $\alpha$ and $\beta$ are empirically set to 0.01. + +# 4. Experimental Results + +# 4.1. Implementation Details + +Evaluation Metrics For quantitative comparison, we employ three widely used metrics: cropping ratio, distortion value, and stability score, as in prior methods [25, 36, 43, 22]. For cropping ratio and distortion value, we first fit a global homography between the input and output videos at each frame. The cropping ratio measures the remaining frame area after cropping out undefined pixels due to motion compensation and is computed as the average scale component of the entire video. The distortion value, which is defined as the worst ratio of the two largest eigenvalues of the affine component across all frames, measures the anisotropic scaling of the homography between the input and output frames. The stability score measures the smoothness of the stabilized videos and the camera path is utilized to determine the value. We compute this metric by using a frequency domain analysis as in Bundled [25]. + +Implementation Details Our network is implemented by PyTorch. We use Adam as the optimizer for training, with + +an initial learning rate of $1 \times 10^{-4}$ and no weight decay. We set $\beta_{1} = 0.9$ , $\beta_{2} = 0.999$ , and $\epsilon = 1e - 8$ , respectively. We train the network for 100,000 iterations. The overall training time on two NVIDIA 1080Ti GPUs is 20 hours. During training, two adjacent frames and their corresponding historical frames are selected as a training sample. The MotionStab dataset comprises 65238 training samples in total. For inference, the overall framework can process a frame of size $640 \times 360$ in real-time. Specifically, we spend 12 ms, 10 ms, and 4 ms to extract camera motion, smooth the camera path, and synthesize stable frames, respectively. + +# 4.2. Comparisons with Existing Methods + +To evaluate the proposed approach, we compare it with the state-of-the-art methods on the NUS dataset [25]. The compared methods include three traditional methods, Bundled [25], Robust L1 [5], Meshflow [22], and five deep learning based methods, DIFRINT [1], Yu et al. [41], PW-StableNet [43], DUT [36], and StabNet [33]. It is worth noting that Meshflow [22], StabNet [33], and ours are online, while the rest are offline. The results of the compared methods are obtained from publicly accessible implementations with default parameters or pre-trained models. + +Quantitative results Table 1 presents the quantitative results for each of the five categories (including regular, quick rotation, zooming, crowd, and parallax), as well as the average results across all categories. From Table 1, we can see that offline approaches generally outperform online meth + +![](images/fad4366167722f0e8f00d9253a521d394314aea67e7394b4858186ae480c2f68.jpg) + +![](images/c50730e5163c7c1520d8fc74f897a652a4ec789c8c85f98aa083bc071fd6685b.jpg) + +![](images/65109fb838b10a7059575f7946138f2ee89ed90f9da2a7c1b7df202f8c969fa7.jpg) + +![](images/83829c3750c8914f90888cff1ed01f6591cff5bc04fec59cd77ca8aa75d8d0b8.jpg) + +![](images/88366a8ba0d4a1fcdc386cbf272d4c9c3615ffca85918ff2c5942cc8567479ba.jpg) + +![](images/60e0a64589b2eecc0990ab4c5269fdf7e5ee9c45b0ae2285f02f6e5b459c924d.jpg) + +![](images/381a2f9486c27f07b408aa52e35e3097591a179010208114301836f30cf987b7.jpg) + +![](images/13fdd79c1779275bf3eb9c30417051cce3f030c050d0a85d99635cc557a46453.jpg) + +![](images/04d95e27f195da35672408352acd26f2a5ff8f7ae3d9f38ec616f6fb7966f865.jpg) + +![](images/b2d602d1818445c7171527dba5e05949126fa2b39b26ba4e222dcfd75b878e51.jpg) + +![](images/7a0995bf53464e9d7c6477dd64210c4a8980e44d0ace36d90a93fc75c407b022.jpg) + +![](images/e8226e73869bcad9521925ec46839eb6ee938297c8972d1ddaaeb83828277e1e.jpg) + +![](images/0da421cc20ae680eeb209c987b9364764d143e1f917f3498a57ca5ee4b6a66ae.jpg) + +![](images/1a39b4bc518ba7ce74fbbb8fb127294549ca1c481a9f5e9201eb507fb8d25604.jpg) + +![](images/ec85eca88e1dfae25eb0b7e6d51c2c8f77d75d56a92d14b2bda9557695c17d7a.jpg) + +![](images/6cb21691cba3f3da6b28b36d2def4409c062445a1558cfbdba448830a30b42d5.jpg) + +![](images/2e2f40175cc13592998b75a7c912b80d99709fb4a8d7ed8b2800a78fa272b88d.jpg) +(a) Meshflow + +![](images/62a38c98c8b31ae2d7043e5a9456a8dc24d7ed70cc9215cad9e6782595eba3d8.jpg) +(b) StabNet + +![](images/5a91124dfbf4cb9f96ae0b55bd2ad6bd6ac6adea671ba7c97b1c4ec461a46b04.jpg) +(c) Ours +Figure 5. Qualitative comparisons with the online methods Meshflow [22] and StabNet [33]. We keep the original warped frames for comparison. The red boxes indicate the preserved frame content after cropping. The red arrows highlight the shear and distortion artifacts. + +![](images/1b834a7bb0f6e499f22a814e7c9b42ba64e79d41ef64643fe561b73a000b41a3.jpg) +(d) Input frame + +ods, especially in challenging scenarios. In comparison to existing online approaches, our method achieves significant performance improvements. Taking Meshflow [22] as the baseline, the cropping ratio and the distortion value of our method increase by $17.25\%$ and $12.18\%$ , respectively. Notably, our method can achieve approaching results to several compared offline methods. + +Qualitative results Fig. 5 illustrates the flaws that can be noticed directly from the video frames, including shear, distortion, and over-cropping. As can be seen, Meshflow suffers from shear and distortion in some scenes due to its reliance on well-optimized parameter tweaking. The shear and over-cropping problems in StabNet [33] are more severe because they directly employ video frames as input for mixed camera motion estimation and path smoothing, making the performance and generalization ability difficult to even approach the traditional approach Meshflow [22]. On the contrary, since our network solely smooths and optimizes the camera path, regardless of image content, it is more generic on diverse challenging scenes and can avoid the aforementioned issues in an online setting. + +User Study We also conduct a user study comparing our method to the PWStableNet [43], which is one of the deep offline approaches that achieves overall good performances according to Table 1. Note that we do not compare with the online methods [22, 33], because our qualitative results are significantly better than theirs. Specifically, we prepare a test set containing 15 videos (3 videos per category), and each of the 20 participants is asked to choose the better one from the results of the two compared methods. The videos are arranged randomly and the original unstable videos are provided. The results of the user study are shown in Fig. 7. + +# 4.3. Ablation Studies + +To analyze the capability of each component, we conduct extensive ablation experiments on the NUS dataset [25]. + +Ablation on losses We first conduct experiments on the motion-consistency loss, the shape-consistency loss, and the scale-preserving loss. In the first row of Table 2, we take the vanilla UNet optimized by the MC loss as our baseline. In the next two rows, we add the SC loss and the SP loss to train the model, respectively. Comparing the first three rows + +![](images/64c8afe9dfbadb16b77839161c267065890a0ec5e1163b5c8c2a9ec7b805aa12.jpg) +(a) MC + +![](images/25102eeddcf1ff26280e87205d00fb675e5528acbbb93ea64ea09470bc0c3bac.jpg) +(b) $\mathrm{MC} + \mathrm{SC}$ + +![](images/a8deaeadd0f4f7c601d6edcd408e6d63c0ae2094ca4d0a5c5a8debbe6ffdac98.jpg) +(c) $\mathrm{MC} + \mathrm{SC} + \mathrm{SP}$ + +![](images/2c0799781a198c07c416afed5c74872644e487e34f85418f3219b75a01465e3a.jpg) +(d) Input frame + +![](images/f905e1e70b7356d73df1c698ae13b2ab887c57408811907bcac6877bc2917db8.jpg) +Figure 6. Qualitative results of the ablation study on the motion-consistency loss (MC), the shape-consistency loss (SC), and the scale-preserving loss (SP). The red arrows show the shear and distortion regions, and the red boxes show the preserved frame region. +Figure 7. User study results comparing with PWStableNet [43]. + +Table 2. Quantitative results of the ablation studies on the hybrid loss and the channel attention mechanism (CA). + +
MCSCSPCACDS
Baseline✓0.800.840.87
Variant 1✓✓0.850.900.86
Variant 2✓✓✓0.900.950.86
Ours✓✓✓✓0.920.980.87
+ +reveals that adding the SC loss and the SP loss respectively improves performance. The best performance is gained by combining them together. Fig. 6 shows some qualitative results. As seen, when only using the MC loss, substantial shear, and distortion occur (Fig. 6 (a), highlighted by red arrows.). The distortion artifacts can be effectively resolved by adding the SC loss (Fig. 6 (b)). However, the scale of the stabilized frame is not well preserved, resulting in larger cropped regions. This issue can eventually be solved by the proposed SP loss (Fig. 6 (c), distinguished by red boxes). + +Analysis of the quality of the dataset To verify the impact of the dataset, we train the network on the DeepStab [33] and our MotionStab dataset, respectively. Fig. 8 shows the quantitative results on the NUS dataset. As seen, when trained using the proposed MotionStab dataset, both our method and StabNet [33] yield better results than training on the DeepStab dataset, respectively, especially in terms of cropping ratio and distortion value. We conclude that the main reasons are twofold. Firstly, our MotionStab dataset contains richer scenarios and unstable motions, improving the performance and generalization ability of the network. + +![](images/56e589c53c1accd1e779900014fb03270eda1dd2feec49c09638bd37909f7d9d.jpg) +Figure 8. Comparisons of the quantitative results between StabNet [33] and our method when trained with different datasets. + +Secondly, the synthesized pairs in MotionStab suffer no parallax issue inherent in DeepStab, leading to fewer distortion artifacts (i.e., higher distortion value) in the stabilized frames. Additionally, our method outperforms StabNet [33] on both datasets, demonstrating its superiority over directly predicting stable warp fields from input video frames. + +# 5. Conclusions + +This work presents a deep camera path optimization framework for online video stabilization. We leave the motion estimation to recent off-the-shelf deep motion models and concentrate on path smoothing. Our model takes a 2D camera path in a sliding window as input and outputs a warp field for the last frame in that window. A video can be stabilized online by applying our model repeatedly for every incoming frame. We introduce a hybrid loss to enhance the spatial and temporal consistency of the stabilized video. Moreover, we created a motion dataset to train our model. Results show that our method outperforms previous approaches both qualitatively and quantitatively. + +Acknowledgements This work was supported by Sichuan Science and Technology Program of China under grants Nos. 2023NSFSC0462, 2023NSFSC1972, 2022YFQ0079, 2021YFG0001, 2022YFG0050, and National Natural Science Foundation of China under grant No.62031009. + +# References + +[1] Jinsoo Choi and In So Kweon. Deep iterative frame interpolation for full-frame video stabilization. ACM Trans. on Graphics (TOG), 39(1):1-9, 2020. 6 +[2] Michael L Gleicher and Feng Liu. Re-cinematography: Improving the camerawork of casual video. ACM transactions on multimedia computing, communications, and applications (TOMM), 5(1):1-28, 2008. 2 +[3] Amit Goldstein and Raanan Fattal. Video stabilization using epipolar geometry. ACM Trans. on Graphics (TOG), 31(5):1-10, 2012. 1, 3 +[4] Matthias Grundmann, Vivek Kwatra, Daniel Castro, and Irfan Essa. Calibration-free rolling shutter removal. In Proc. ICCP, pages 1-8, 2012. 2, 3 +[5] Matthias Grundmann, Vivek Kwatra, and Irfan Essa. Autodirected video stabilization with robust 11 optimal camera paths. In Proc. CVPR, pages 225-232, 2011. 1, 2, 6 +[6] Wilko Guilluy, Laurent Oudre, and Azedine Beghdadi. Video stabilization: Overview, challenges and perspectives. Signal Processing: Image Communication, 90:116015, 2021. 1 +[7] Richard Hartley and Andrew Zisserman. Multiple view geometry in computer vision. Cambridge university press, 2003. 3 +[8] Mingbo Hong, Yuhang Lu, Nianjin Ye, Chunyu Lin, Qijun Zhao, and Shuaicheng Liu. Unsupervised homography estimation with coplanarity-aware gan. In Proc. CVPR, pages 17663-17672, 2022. 1, 3 +[9] Jie Hu, Li Shen, and Gang Sun. Squeeze-and-excitation networks. In Proc. CVPR, pages 7132-7141, 2018. 4 +[10] Chia-Hung Huang, Hang Yin, Yu-Wing Tai, and Chi-Keung Tang. Stablenet: semi-online, multi-scale deep video stabilization. arXiv preprint arXiv:1907.10283, 2019. 4 +[11] Maria Silvia Ito and Ebroul Izquierdo. A dataset and evaluation framework for deep learning based video stabilization systems. In Proc. VCIP, pages 1-4. IEEE, 2019. 4 +[12] Dengchao Jin, Jianjun Lei, Bo Peng, Wanqing Li, Nam Ling, and Qingming Huang. Deep affine motion compensation network for inter prediction in vvc. IEEE Trans. on Circuits and Systems for Video Technology, 32(6):3923-3933, 2021. 1 +[13] Neel Joshi, Wolf Kienzle, Mike Toelle, Matt Uytendaele, and Michael F Cohen. Real-time hyperlapse creation via optimal frame selection. ACM Transactions on Graphics (TOG), 34(4):1-9, 2015. 3 +[14] Alexandre Karpenko, David Jacobs, Jongmin Baek, and Marc Levoy. Digital video stabilization and rolling shutter correction using gyroscopes. CSTR, 1(2):13, 2011. 3 +[15] Johannes Kopf. 360 video stabilization. ACM Transactions on Graphics (TOG), 35(6):1-9, 2016. 3 +[16] Ken-Yi Lee, Yung-Yu Chuang, Bing-Yu Chen, and Ming Ouhyoung. Video stabilization using robust feature trajectories. In Proc. CVPR, pages 1397-1404, 2009. 2 +[17] Yao-Chih Lee, Kuan-Wei Tseng, Yu-Ta Chen, Chien-Cheng Chen, Chu-Song Chen, and Yi-Ping Hung. 3d video stabilization with depth estimation by cnn-based optimization. In Proc. CVPR, pages 10621–10630, 2021. 1 + +[18] Feng Liu, Michael Gleicher, Hailin Jin, and Aseem Agarwala. Content-preserving warps for 3d video stabilization. ACM Trans. on Graphics (ToG), 28(3):1-9, 2009. 1, 3 +[19] Feng Liu, Michael Gleicher, Jue Wang, Hailin Jin, and Aseem Agarwala. Subspace video stabilization. ACM Trans. on Graphics (TOG), 30(1):1-10, 2011. 3 +[20] Shuaicheng Liu, Mingyu Li, Shuyuan Zhu, and Bing Zeng. Codingflow: Enable video coding for video stabilization. IEEE Trans. on Image Processing, 26(7):3291-3302, 2017. 1, 3 +[21] Shuaicheng Liu, Yuhang Lu, Hai Jiang, Nianjin Ye, Chuan Wang, and Bing Zeng. Unsupervised global and local homography estimation with motion basis learning. IEEE Trans. on Pattern Analysis and Machine Intelligence, 2022. 1 +[22] Shuaicheng Liu, Ping Tan, Lu Yuan, Jian Sun, and Bing Zeng. Meshflow: Minimum latency online video stabilization. In Proc. ECCV, pages 800-815, 2016. 1, 2, 3, 6, 7 +[23] Shuaicheng Liu, Yinting Wang, Lu Yuan, Jiajun Bu, Ping Tan, and Jian Sun. Video stabilization with a depth camera. In Proc. CVPR, pages 89-95, 2012. 1, 3 +[24] Shuaicheng Liu, Nianjin Ye, Chuan Wang, Kunming Luo, Jue Wang, and Jian Sun. Content-aware unsupervised deep homography estimation and beyond. IEEE Trans. on Pattern Analysis and Machine Intelligence, 2022. 1 +[25] Shuaicheng Liu, Lu Yuan, Ping Tan, and Jian Sun. Bundled camera paths for video stabilization. ACM Trans. on Graphics (TOG), 32(4):1-10, 2013. 1, 2, 3, 6, 7 +[26] Shuaicheng Liu, Lu Yuan, Ping Tan, and Jian Sun. Steadyflow: Spatially smooth optical flow for video stabilization. In Proc. CVPR, pages 4209-4216, 2014. 1, 2, 3 +[27] Yasuyuki Matsushita, Eyal Ofek, Weina Ge, Xiaou Tang, and Heung-Yeung Shum. Full-frame video stabilization with motion inpainting. IEEE Trans. on Pattern Analysis and Machine Intelligence, 28(7):1150-1163, 2006. 1, 2 +[28] Lang Nie, Chunyu Lin, Kang Liao, Shuaicheng Liu, and Yao Zhao. Depth-aware multi-grid deep homography estimation with contextual correlation. IEEE Trans. on Circuits and Systems for Video Technology, 32(7):4460-4472, 2022. 1 +[29] Hui Qu, Li Song, and Gengjian Xue. Shaking video synthesis for video stabilization performance assessment. In Proc. VCIP, pages 1-6. IEEE, 2013. 4 +[30] Ethan Rublee, Vincent Rabaud, Kurt Konolige, and Gary Bradski. Orb: An efficient alternative to sift or surf. In Proc. ICCV, pages 2564-2571, 2011. 2 +[31] Jianbo Shi et al. Good features to track. In Proc. CVPR, pages 593-600, 1994. 2 +[32] Brandon M Smith, Li Zhang, Hailin Jin, and Aseem Agarwala. Light field video stabilization. In Proc. ICCV, pages 341-348, 2009. 3 +[33] Miao Wang, Guo-Ye Yang, Jin-Kun Lin, Song-Hai Zhang, Ariel Shamir, Shao-Ping Lu, and Shi-Min Hu. Deep online video stabilization with multi-grid warping transformation learning. IEEE Trans. on Image Processing, 28(5):2283-2292, 2018. 1, 2, 3, 4, 5, 6, 7, 8 +[34] Yu-Shuen Wang, Feng Liu, Pu-Sheng Hsu, and Tong-Yee Lee. Spatially and temporally optimized video stabiliza + +tion. IEEE Trans. on Visualization and Computer Graphics, 19(8):1354-1361, 2013. 2, 3 +[35] Sen-Zhe Xu, Jun Hu, Miao Wang, Tai-Jiang Mu, and ShiMin Hu. Deep video stabilization using adversarial networks. In Computer Graphics Forum, volume 37, pages 267-276, 2018. 1, 3 +[36] Yufei Xu, Jing Zhang, Stephen J Maybank, and Dacheng Tao. Dut: Learning video stabilization by simply watching unstable videos. IEEE Trans. on Image Processing, 31:4306-4320, 2022. 6 +[37] Junlan Yang, Dan Schonfeld, Chong Chen, and Magdi Mohamed. Online video stabilization based on particle filters. In Proc. ICIP, pages 1545-1548, 2006. 3 +[38] Nianjin Ye, Chuan Wang, Haoqiang Fan, and Shuaicheng Liu. Motion basis learning for unsupervised deep homography estimation with subspace projection. In Proc. ICCV, pages 13117-13125, October 2021. 1, 3 +[39] Nianjin Ye, Chuan Wang, Shuaicheng Liu, Lanpeng Jia, Jue Wang, and Yongqing Cui. Deepmeshflow: Content adaptive mesh deformation for robust image registration. arXiv preprint arXiv:1912.05131, 2019. 1, 2, 3, 4, 5 +[40] Jiyang Yu and Ravi Ramamoorthi. Robust video stabilization by optimization in cnn weight space. In Proc. CVPR, pages 3800-3808, 2019. 3 +[41] Jiyang Yu and Ravi Ramamoorthi. Learning video stabilization using optical flow. In Proc. CVPR, pages 8159-8167, 2020. 1, 3, 6 +[42] Jiyang Yu, Ravi Ramamoorthi, Keli Cheng, Michel Sarkis, and Ning Bi. Real-time selfie video stabilization. In Proc. CVPR, pages 12036-12044, 2021. 3 +[43] Minda Zhao and Qiang Ling. Pwstablenet: Learning pixelwise warping maps for video stabilization. IEEE Trans. on Image Processing, 29:3582-3595, 2020. 6, 7, 8 \ No newline at end of file diff --git a/2023/Minimum Latency Deep Online Video Stabilization/images.zip b/2023/Minimum Latency Deep Online Video Stabilization/images.zip new file mode 100644 index 0000000000000000000000000000000000000000..aadf4cd51b65c063275aed11bbea8a11c0c3d4de --- /dev/null +++ b/2023/Minimum Latency Deep Online Video Stabilization/images.zip @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:92d4a446e8806accdc2b49ecde9766f1256fb1d997b7797800782e6be3b84e5a +size 777952 diff --git a/2023/Minimum Latency Deep Online Video Stabilization/layout.json b/2023/Minimum Latency Deep Online Video Stabilization/layout.json new file mode 100644 index 0000000000000000000000000000000000000000..51c2ed9f266d3ecc1bba8d79e5ab4ec595ca5a1f --- /dev/null +++ b/2023/Minimum Latency Deep Online Video Stabilization/layout.json @@ -0,0 +1,9883 @@ +{ + "pdf_info": [ + { + "para_blocks": [ + { + "bbox": [ + 138, + 103, + 455, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 138, + 103, + 455, + 121 + ], + "spans": [ + { + "bbox": [ + 138, + 103, + 455, + 121 + ], + "type": "text", + "content": "Minimum Latency Deep Online Video Stabilization" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "spans": [ + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "text", + "content": "Zhuofan Zhang" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "inline_equation", + "content": "^{1*}" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "text", + "content": " Zhen Liu" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "inline_equation", + "content": "^{2*}" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "text", + "content": " Ping Tan" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "text", + "content": " Bing Zeng" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "text", + "content": " Shuaicheng Liu" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "inline_equation", + "content": "^{1,2\\dagger}" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "inline_equation", + "content": "^{1}" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "text", + "content": "University of Electronic Science and Technology of China " + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "inline_equation", + "content": "^{2}" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "text", + "content": "Megvii Technology \n" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "inline_equation", + "content": "^{3}" + }, + { + "bbox": [ + 83, + 148, + 512, + 191 + ], + "type": "text", + "content": "The Hong Kong University of Science and Technology" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 150, + 193, + 441, + 219 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 150, + 193, + 441, + 219 + ], + "spans": [ + { + "bbox": [ + 150, + 193, + 441, + 219 + ], + "type": "text", + "content": "{zhangzf98@std., eezeng@, liushuaicheng@}uestc.edu.cn, liuzhen03@megvii.com, pingtan@ust.hk" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 143, + 247, + 192, + 260 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 143, + 247, + 192, + 260 + ], + "spans": [ + { + "bbox": [ + 143, + 247, + 192, + 260 + ], + "type": "text", + "content": "Abstract" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 272, + 290, + 548 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 272, + 290, + 548 + ], + "spans": [ + { + "bbox": [ + 46, + 272, + 290, + 548 + ], + "type": "text", + "content": "We present a novel camera path optimization framework for the task of online video stabilization. Typically, a stabilization pipeline consists of three steps: motion estimating, path smoothing, and novel view rendering. Most previous methods concentrate on motion estimation, proposing various global or local motion models. In contrast, path optimization receives relatively less attention, especially in the important online setting, where no future frames are available. In this work, we adopt recent off-the-shelf high-quality deep motion models for motion estimation to recover the camera trajectory and focus on the latter two steps. Our network takes a short 2D camera path in a sliding window as input and outputs the stabilizing warp field of the last frame in the window, which warps the coming frame to its stabilized position. A hybrid loss is well-defined to constrain the spatial and temporal consistency. In addition, we build a motion dataset that contains stable and unstable motion pairs for the training. Extensive experiments demonstrate that our approach significantly outperforms state-of-the-art online methods both qualitatively and quantitatively and achieves comparable performance to offline methods. Our code and dataset are available at https://github.com/1iuzhen03/NNDVS." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 570, + 128, + 582 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 570, + 128, + 582 + ], + "spans": [ + { + "bbox": [ + 47, + 570, + 128, + 582 + ], + "type": "text", + "content": "1. Introduction" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 590, + 287, + 687 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 590, + 287, + 687 + ], + "spans": [ + { + "bbox": [ + 46, + 590, + 287, + 687 + ], + "type": "text", + "content": "Video stabilization methods aim at removing unwanted shaky motions of a video caused by unsteady moving capture [6]. Traditional methods often take three main steps: 1) camera motion estimating for trajectory recovery; 2) camera path smoothing; and 3) steady frame synthesis. According to the adopted motion model in the first step, these methods can be broadly classified as 2D or 3D. 2D methods adopt planar motion models such as affine [5], or homog-" + } + ] + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 310, + 248, + 542, + 296 + ], + "blocks": [ + { + "bbox": [ + 310, + 248, + 542, + 296 + ], + "lines": [ + { + "bbox": [ + 310, + 248, + 542, + 296 + ], + "spans": [ + { + "bbox": [ + 310, + 248, + 542, + 296 + ], + "type": "image", + "image_path": "449348ad10987f8b6c931b47b383dd675705882a671aed3ada8357c1b4715c65.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 347, + 299, + 500, + 310 + ], + "lines": [ + { + "bbox": [ + 347, + 299, + 500, + 310 + ], + "spans": [ + { + "bbox": [ + 347, + 299, + 500, + 310 + ], + "type": "text", + "content": "(a) Illustration of the dataset synthesis process." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 308, + 323, + 425, + 388 + ], + "blocks": [ + { + "bbox": [ + 308, + 323, + 425, + 388 + ], + "lines": [ + { + "bbox": [ + 308, + 323, + 425, + 388 + ], + "spans": [ + { + "bbox": [ + 308, + 323, + 425, + 388 + ], + "type": "image", + "image_path": "4bc2f3f7163e496eb982983f88e49cc3d493363aa8aa460c044ffc6b8ce04316.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 347, + 394, + 499, + 404 + ], + "lines": [ + { + "bbox": [ + 347, + 394, + 499, + 404 + ], + "spans": [ + { + "bbox": [ + 347, + 394, + 499, + 404 + ], + "type": "text", + "content": "(b) Illustration of the synthesized camera path." + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_caption" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 428, + 323, + 544, + 388 + ], + "blocks": [ + { + "bbox": [ + 428, + 323, + 544, + 388 + ], + "lines": [ + { + "bbox": [ + 428, + 323, + 544, + 388 + ], + "spans": [ + { + "bbox": [ + 428, + 323, + 544, + 388 + ], + "type": "image", + "image_path": "05e2eb8628669596f644c9ca8a5c3774a1d3dbdd856941d93dff85b9647f9281.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 304, + 409, + 546, + 453 + ], + "lines": [ + { + "bbox": [ + 304, + 409, + 546, + 453 + ], + "spans": [ + { + "bbox": [ + 304, + 409, + 546, + 453 + ], + "type": "text", + "content": "Figure 1. Illustration of the dataset synthesis process (a) and the synthesized camera path (b). We transfer an unstable path to a stable path, creating a synthesized path, which shares high frequencies of the unstable path with low frequencies of the stable path." + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 473, + 545, + 510 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 473, + 545, + 510 + ], + "spans": [ + { + "bbox": [ + 304, + 473, + 545, + 510 + ], + "type": "text", + "content": "raphy [27], or mesh [25, 22, 33], or flow [26, 20, 41], while 3D methods resort to 3D depth [23, 17], or reconstructed points [18], or epipolar geometry constraints [3]." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 510, + 546, + 605 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 510, + 546, + 605 + ], + "spans": [ + { + "bbox": [ + 304, + 510, + 546, + 605 + ], + "type": "text", + "content": "In comparison, deep learning-based methods learn stabilization models from stable and unstable video pairs [33, 41, 35] without explicit steps of motion estimation and smoothing. However, the results of deep methods are often visually inferior to those of traditional ones. A potential reason is that these methods try to learn the three steps all in a unified framework, each of which has different characteristics but is learned in the network blindly." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 605, + 547, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 605, + 547, + 714 + ], + "spans": [ + { + "bbox": [ + 304, + 605, + 547, + 714 + ], + "type": "text", + "content": "On the other hand, deep affine [12], deep homography [38, 8], and deep mesh models [39, 24, 21, 28] have demonstrated high-quality image registration, even under adverse cases. They are robust to scenes with large depth variation, large dynamic objects, and poor textures, fitting perfectly for the camera motion estimation. In this work, we argue that it is not necessary to enclose all three steps of the stabilization into the learning pipeline, but let the motion estimation to the recent deep motion models [39, 24]." + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "spans": [ + { + "bbox": [ + 65, + 2, + 111, + 34 + ], + "type": "text", + "content": "CVF" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "header", + "angle": 0, + "lines": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "spans": [ + { + "bbox": [ + 146, + 0, + 494, + 37 + ], + "type": "text", + "content": "This ICCV paper is the Open Access version, provided by the Computer Vision Foundation. Except for this watermark, it is identical to the accepted version; the final published version of the proceedings is available on IEEE Xplore." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 58, + 693, + 124, + 703 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 58, + 693, + 124, + 703 + ], + "spans": [ + { + "bbox": [ + 58, + 693, + 124, + 703 + ], + "type": "text", + "content": "*Equal contribution" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 59, + 703, + 134, + 712 + ], + "type": "page_footnote", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 703, + 134, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 703, + 134, + 712 + ], + "type": "text", + "content": "† Corresponding author" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 758 + ], + "type": "text", + "content": "23030" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 0 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 287, + 108 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 287, + 108 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 287, + 108 + ], + "type": "text", + "content": "In this way, our network only focuses on learning to stabilize the shaky camera motion, which makes the learning process much more efficient and effective." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 110, + 286, + 228 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 110, + 286, + 228 + ], + "spans": [ + { + "bbox": [ + 46, + 110, + 286, + 228 + ], + "type": "text", + "content": "Camera path smoothing can be performed offline or online, where the former optimizes the path globally while the latter smooths the path on-the-fly. In other words, offline approaches have access to all past and future frames during optimization, as it often stabilizes a video after it is captured. In contrast, online methods aim to stabilize a video during the capture. Note that, the concept of real-time differs from that of online, as an online method must be in real-time whereas an offline method can run at real-time speed. The main distinction is the availability of future frames." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 46, + 231, + 286, + 445 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 231, + 286, + 445 + ], + "spans": [ + { + "bbox": [ + 46, + 231, + 286, + 445 + ], + "type": "text", + "content": "Most existing methods are offline [25, 5, 4, 34, 26]. However, the online setting is critical as many applications desire instant visual feedback based on live video streams [22, 33]. Normally, with limited or even no access to future frames, online methods cannot achieve equal stability as offline methods, particularly in the suppression of the low-frequency camera shake, which frequently necessitates a long camera path. One may argue that online methods can have all the past frames for processing. However, future motions are important, if not more important than the past. Because, for one thing, fast camera motions can happen at any time suddenly, e.g., quick rotation or zooming. The reaction time is short. Inappropriate processing may either decrease the stability or create artifacts such as excessive cropping. For another, all the past frames have already been shown to the audience, meaning that they are fixed, and thus cannot be modified. We can only adjust the unstabled future frames to the frozen past ones." + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 448, + 286, + 699 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 448, + 286, + 699 + ], + "spans": [ + { + "bbox": [ + 46, + 448, + 286, + 699 + ], + "type": "text", + "content": "To this end, we propose a deep online camera path smooth network that takes a pre-estimated short 2D camera trajectory in a sliding window as input and outputs the motion compensation warp field of the last frame in the window for the stabilized view, which is the setting of online stabilization with the minimum latency. A video can be stabilized on the fly by applying our model repeatedly for every incoming frame. To deal with depth changes and moving objects, we employ the mesh-based motion model [39] which demonstrates excellent robustness in various scenes. Instead of directly inputting the mesh structure or mesh cells as local homographies to the network, we convert the estimated motion to a dense flow field, which can be fed into the convolutional neural network naturally. We show that it is a more convenient representation compared to other alternatives, e.g., vertex sparse motion vectors or homography matrix, which cannot be easily adapted as input to CNNs. Based on that, we further propose a hybrid loss, which consists of the motion-consistency loss, the shape-consistency loss, and the scale-preserving loss, to maintain the spatial coherence and temporal continuity of the stabilized video." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 59, + 701, + 286, + 712 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 59, + 701, + 286, + 712 + ], + "spans": [ + { + "bbox": [ + 59, + 701, + 286, + 712 + ], + "type": "text", + "content": "Besides, we create a motion dataset, MotionStab, to" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 304, + 72, + 545, + 226 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 72, + 545, + 226 + ], + "spans": [ + { + "bbox": [ + 304, + 72, + 545, + 226 + ], + "type": "text", + "content": "train our network. In particular, we capture 110 stable videos with a cell phone mounted on a hand-held physical stabilizer. Then, we create a shaky video by transforming each frame of the stable video according to the motion of another irrelevant shaky video. In this way, the stable and unstable motion pairs can be constructed. Fig. 1 shows our idea. Note that, our dataset is different from DeepStab [33], which is captured by a stable and a shaky camera simultaneously. We directly transfer the motion of a shaky video to a stable video. The contents of the two videos are not important but the motion does. That means DeepStab [33] offers frame pairs, while our MotionStab offers motion pairs. We feed the motions to the network instead of RGB frames." + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 304, + 228, + 545, + 359 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 228, + 545, + 359 + ], + "spans": [ + { + "bbox": [ + 304, + 228, + 545, + 359 + ], + "type": "text", + "content": "The benefits are three folds: 1) image contents are diverse, while motion mappings are much easier to learn; 2) motion as mesh is lightweight, so does the network; 3) the network can be more focused by excluding the task of the motion estimation. As a result, we show that this motion learning pipeline is effective enough, such that it can work with straightforward network architectures, e.g., UNet, without help from more advanced designs or sophisticated modules. Complex motion types can be learned by the network successfully, as long as they exist in the training data. As such, the network can be kept simple yet effective." + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 360, + 545, + 383 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 360, + 545, + 383 + ], + "spans": [ + { + "bbox": [ + 305, + 360, + 545, + 383 + ], + "type": "text", + "content": "In summary, the main contributions of this paper are concluded as follows:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 317, + 393, + 545, + 541 + ], + "type": "list", + "angle": 0, + "index": 12, + "blocks": [ + { + "bbox": [ + 317, + 393, + 545, + 416 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 393, + 545, + 416 + ], + "spans": [ + { + "bbox": [ + 317, + 393, + 545, + 416 + ], + "type": "text", + "content": "- We propose a novel deep camera path optimization framework for online video stabilization." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 317, + 427, + 545, + 462 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 427, + 545, + 462 + ], + "spans": [ + { + "bbox": [ + 317, + 427, + 545, + 462 + ], + "type": "text", + "content": "- We propose a hybrid loss to enable robust supervision for maintaining the spatial and temporal coherence of the stabilized video." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 317, + 473, + 545, + 497 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 473, + 545, + 497 + ], + "spans": [ + { + "bbox": [ + 317, + 473, + 545, + 497 + ], + "type": "text", + "content": "- We build a comprehensive MotionStab dataset that covers various motions for camera path optimization." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 317, + 506, + 545, + 541 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 317, + 506, + 545, + 541 + ], + "spans": [ + { + "bbox": [ + 317, + 506, + 545, + 541 + ], + "type": "text", + "content": "- We conduct extensive experiments to demonstrate the effectiveness of the proposed approach against existing state-of-the-art online and offline methods." + } + ] + } + ], + "index": 11 + } + ], + "sub_type": "text" + }, + { + "bbox": [ + 306, + 555, + 397, + 567 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 555, + 397, + 567 + ], + "spans": [ + { + "bbox": [ + 306, + 555, + 397, + 567 + ], + "type": "text", + "content": "2. Related Works" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 306, + 574, + 424, + 586 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 574, + 424, + 586 + ], + "spans": [ + { + "bbox": [ + 306, + 574, + 424, + 586 + ], + "type": "text", + "content": "2.1. Traditional Methods" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 594, + 545, + 713 + ], + "type": "text", + "content": "Early 2D approaches track image features for several frames and then smooth these feature trajectories to stabilize a video [16, 34]. However, long feature tracks [31] are hard to be obtained when large camera motions exist. Later, motion models, such as affine [5] or homography [27, 2], are calculated between neighboring frames, relaxing the requirement of long feature tracks into feature matches [30] between adjacent frames. Then, these motion models are accumulated to generate a 2D camera trajectory, which is shown to be a good replacement against" + } + ] + } + ], + "index": 15 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "text", + "content": "23031" + } + ] + } + ], + "index": 16 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 1 + }, + { + "para_blocks": [ + { + "bbox": [ + 46, + 72, + 286, + 156 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 72, + 286, + 156 + ], + "spans": [ + { + "bbox": [ + 46, + 72, + 286, + 156 + ], + "type": "text", + "content": "track-based approaches, owning largely improved robustness. With respect to the motion representation, homography mixture [4], mesh [25, 22, 34], and optical flow [26, 20] based motion models are proposed to deal with scenes that contain large depth variations. Besides, some approaches focus on special stabilization tasks, such as Selfie [42], 360 [15], and hyperlapse videos [13]." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 46, + 157, + 286, + 312 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 157, + 286, + 312 + ], + "spans": [ + { + "bbox": [ + 46, + 157, + 286, + 312 + ], + "type": "text", + "content": "On the other hand, 3D-based methods require 3D camera motions or scene structure for stabilization. The 3D structure can either be calculated from the video by structure-from-motion (SfM) [18] or acquired from additional hardware, such as a depth camera [23], a gyroscope sensor [14], or a light field camera [32]. However, full 3D stabilization is fragile and computationally expensive [18]. Partial 3D methods proposed 3D constraints, such as subspace projection [19] and epipolar geometry [3], to alleviate the requirement of full 3D reconstruction [7]. Normally, 3D methods can better handle the scene parallax compared with 2D approaches due to the physical correctness, as long as the 3D information can be available." + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 320, + 183, + 333 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 320, + 183, + 333 + ], + "spans": [ + { + "bbox": [ + 47, + 320, + 183, + 333 + ], + "type": "text", + "content": "2.2. Deep Learning Methods" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 46, + 339, + 286, + 471 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 339, + 286, + 471 + ], + "spans": [ + { + "bbox": [ + 46, + 339, + 286, + 471 + ], + "type": "text", + "content": "Deep methods take the video frames as input and directly output the stabilized frames, which are often trained with stable and unstable frame pairs acquired by special hardware, e.g., DeepStab dataset [33]. Xu et al. used the adversarial network to generate a target image to guide the warping [35]. Yu et al. learned the flow fields from initial optical flow estimation for the accurate per-pixel motion compensation [41]. Deep methods suffer from the generalization problem, given that DeepStab only contains 60 videos. Yu et al. used the CNN as the optimizer instead of learning from data to overfit each input example [40]." + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 46, + 472, + 286, + 555 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 472, + 286, + 555 + ], + "spans": [ + { + "bbox": [ + 46, + 472, + 286, + 555 + ], + "type": "text", + "content": "Recently, deep motion models have achieved good results for motion estimation, such as deep homography [38, 8] and deep meshflow [39], which is more robust in adverse cases compared to traditional solutions, such as scenes of low texture and low light. In this work, we adopt the deep meshflow [39] for our camera motion estimator and design a network concentrating on camera path smoothing." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 563, + 160, + 576 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 563, + 160, + 576 + ], + "spans": [ + { + "bbox": [ + 47, + 563, + 160, + 576 + ], + "type": "text", + "content": "2.3. Online Approaches" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": "Most of the video stabilization approaches are offline, where a video is processed after it has been captured. Online methods stabilize a video during the capture [37, 33, 22]. One may argue that global path optimization can be easily modified to online methods by applying a sliding window scheme. However, the stability would inevitably decrease, let alone the existence of challenging camera motions, such as quick rotation and zooming, which may introduce artifacts such as wobble and excessive cropping. Previously, these difficult motions can only be solved satisfactorily by global camera path smoothing. In this work," + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 305, + 72, + 545, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 72, + 545, + 96 + ], + "spans": [ + { + "bbox": [ + 305, + 72, + 545, + 96 + ], + "type": "text", + "content": "we propose to solve these problems with our proposed deep online camera path optimization framework." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 306, + 106, + 388, + 121 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 106, + 388, + 121 + ], + "spans": [ + { + "bbox": [ + 306, + 106, + 388, + 121 + ], + "type": "text", + "content": "3. Methodology" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 306, + 126, + 429, + 138 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 126, + 429, + 138 + ], + "spans": [ + { + "bbox": [ + 306, + 126, + 429, + 138 + ], + "type": "text", + "content": "3.1. Problem Formulation" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "spans": [ + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "text", + "content": "Our method is built upon convolutional neural networks. As illustrated in Fig. 3 (a), given an incoming unsteady frame " + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "inline_equation", + "content": "I_{t}" + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "text", + "content": " at timestamp " + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "text", + "content": ", our deep online video stabilization aims to predict the corresponding steady frame " + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "inline_equation", + "content": "I_{t}^{\\prime}" + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "text", + "content": " with no future frames. Here, we use “/” to represent predicted quantities. Note that, previous learning-based methods learn the mapping " + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "inline_equation", + "content": "f(\\cdot)" + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "text", + "content": " from the input shaky RGB frames and predict a warp field " + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "inline_equation", + "content": "B_{t}^{\\prime}" + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "text", + "content": " of frame " + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "inline_equation", + "content": "I_{t}" + }, + { + "bbox": [ + 305, + 144, + 545, + 240 + ], + "type": "text", + "content": ", which can be formulated as" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 388, + 250, + 545, + 264 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 388, + 250, + 545, + 264 + ], + "spans": [ + { + "bbox": [ + 388, + 250, + 545, + 264 + ], + "type": "interline_equation", + "content": "\\left\\{B _ {t} ^ {\\prime} \\right\\} = f \\left(\\left\\{I _ {t} \\right\\}\\right), \\tag {1}", + "image_path": "0d860c1ebce4ebfbff77249b75f4fa2e3eb8cdba9a02ebab9a5a2e04f3b69c39.jpg" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 272, + 545, + 332 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 272, + 545, + 332 + ], + "spans": [ + { + "bbox": [ + 304, + 272, + 545, + 332 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 272, + 545, + 332 + ], + "type": "inline_equation", + "content": "\\{\\cdot\\}" + }, + { + "bbox": [ + 304, + 272, + 545, + 332 + ], + "type": "text", + "content": " represents a set of elements. However, our experiments show that directly using complex RGB video frames as input and mixing motion estimation and path smoothing in a network frequently causes estimation errors, resulting in wobbling and distortion artifacts." + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "spans": [ + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "type": "text", + "content": "In this work, we propose our approach from a novel perspective, where we separate the motion estimation step from the network alone and leave the network focus on camera path smoothing. Specifically, we consider using a fixed window of " + }, + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "type": "text", + "content": " past frames " + }, + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "type": "inline_equation", + "content": "\\{I_t\\}_r = \\langle I_{t - r},\\dots,I_{t - 1},I_t\\rangle" + }, + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "type": "text", + "content": " of minimum latency (i.e. without using future frames) to stabilize the incoming target frame " + }, + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "type": "inline_equation", + "content": "I_{t}" + }, + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "type": "text", + "content": ". The camera motion " + }, + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "type": "inline_equation", + "content": "\\{F_t\\}" + }, + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "type": "text", + "content": " is estimated by an off-the-shelf deep motion estimation model. Our camera path smooth network uses only the estimated motion as input to predict the corresponding warp field " + }, + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "type": "inline_equation", + "content": "B_t'" + }, + { + "bbox": [ + 305, + 333, + 545, + 464 + ], + "type": "text", + "content": ", i.e.," + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 383, + 472, + 545, + 488 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 383, + 472, + 545, + 488 + ], + "spans": [ + { + "bbox": [ + 383, + 472, + 545, + 488 + ], + "type": "interline_equation", + "content": "\\left\\{B _ {t} ^ {\\prime} \\right\\} = \\Phi \\left(\\left\\{F _ {t} \\right\\}; \\theta\\right), \\tag {2}", + "image_path": "de4f563cfd733110746d6410949420f2c536875f8a09a8a5acb10d987bf71abd.jpg" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 305, + 496, + 545, + 533 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 496, + 545, + 533 + ], + "spans": [ + { + "bbox": [ + 305, + 496, + 545, + 533 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 496, + 545, + 533 + ], + "type": "inline_equation", + "content": "\\Phi(\\cdot)" + }, + { + "bbox": [ + 305, + 496, + 545, + 533 + ], + "type": "text", + "content": " denotes the camera path smoothing network and " + }, + { + "bbox": [ + 305, + 496, + 545, + 533 + ], + "type": "inline_equation", + "content": "\\theta" + }, + { + "bbox": [ + 305, + 496, + 545, + 533 + ], + "type": "text", + "content": " is the network parameters to be optimized. We empirically set " + }, + { + "bbox": [ + 305, + 496, + 545, + 533 + ], + "type": "inline_equation", + "content": "r" + }, + { + "bbox": [ + 305, + 496, + 545, + 533 + ], + "type": "text", + "content": " to 15 in our experiments." + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 540, + 516, + 553 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 540, + 516, + 553 + ], + "spans": [ + { + "bbox": [ + 306, + 540, + 516, + 553 + ], + "type": "text", + "content": "3.2. Deep Online Camera Path Optimization" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 558, + 545, + 654 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 558, + 545, + 654 + ], + "spans": [ + { + "bbox": [ + 304, + 558, + 545, + 654 + ], + "type": "text", + "content": "As shown in Fig. 2, the overall pipeline of the proposed deep online camera path optimization framework mainly consists of three stages. Firstly, we adopt a deep motion extraction model for robust camera motion estimation. Secondly, the camera path smooth network takes the unsteady camera motion as input and predicts the smoothed warp field. Finally, the original shaky frame is transformed by the predicted warp field to synthesize the target steady frame." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": "Camera Motion Estimation The first step is to estimate the camera motion. We employ an optimized deep mesh-flow model [39] to extract the inter-frame motion. Specifically, given the incoming frame " + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "inline_equation", + "content": "I_{t}" + }, + { + "bbox": [ + 304, + 665, + 545, + 713 + ], + "type": "text", + "content": " and past adjacent frame" + } + ] + } + ], + "index": 18 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23032" + } + ] + } + ], + "index": 19 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 2 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 63, + 70, + 532, + 259 + ], + "blocks": [ + { + "bbox": [ + 63, + 70, + 532, + 259 + ], + "lines": [ + { + "bbox": [ + 63, + 70, + 532, + 259 + ], + "spans": [ + { + "bbox": [ + 63, + 70, + 532, + 259 + ], + "type": "image", + "image_path": "bc01b6585b98bd47570dab0021445423a4c5d6485ca18a1476aee7a6f2f5b394.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 46, + 264, + 547, + 299 + ], + "lines": [ + { + "bbox": [ + 46, + 264, + 547, + 299 + ], + "spans": [ + { + "bbox": [ + 46, + 264, + 547, + 299 + ], + "type": "text", + "content": "Figure 2. The overall pipeline of the proposed deep online camera path optimization framework. (a) We first employ a deep motion extraction model to estimate the unsteady camera motion. (b) Then, the estimated motion is fed into the camera path smooth network, yielding the smoothed warp field. (c) Finally, the target steady frame is synthesized by the predicted smooth warp field." + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 50, + 316, + 157, + 390 + ], + "blocks": [ + { + "bbox": [ + 50, + 316, + 157, + 390 + ], + "lines": [ + { + "bbox": [ + 50, + 316, + 157, + 390 + ], + "spans": [ + { + "bbox": [ + 50, + 316, + 157, + 390 + ], + "type": "image", + "image_path": "e154d9df9a963fc93899e9f318b36fb40dcb138ce76f8fb5f182457357377c1e.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 99, + 393, + 111, + 403 + ], + "lines": [ + { + "bbox": [ + 99, + 393, + 111, + 403 + ], + "spans": [ + { + "bbox": [ + 99, + 393, + 111, + 403 + ], + "type": "text", + "content": "(a)" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 176, + 316, + 282, + 390 + ], + "blocks": [ + { + "bbox": [ + 176, + 316, + 282, + 390 + ], + "lines": [ + { + "bbox": [ + 176, + 316, + 282, + 390 + ], + "spans": [ + { + "bbox": [ + 176, + 316, + 282, + 390 + ], + "type": "image", + "image_path": "993bf0d2ef9444d76e7503ff2ec5b357403a89a63584c45007cf0123625be8a5.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 225, + 393, + 236, + 403 + ], + "lines": [ + { + "bbox": [ + 225, + 393, + 236, + 403 + ], + "spans": [ + { + "bbox": [ + 225, + 393, + 236, + 403 + ], + "type": "text", + "content": "(b)" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "lines": [ + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "spans": [ + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "type": "text", + "content": "Figure 3. Relationships between the unstable/synthesized video and the stable video. (a) depicts the basic relationships of the unstable video " + }, + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "type": "inline_equation", + "content": "\\{I_t\\}" + }, + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "type": "text", + "content": " and stabilized video " + }, + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "type": "inline_equation", + "content": "\\{I_t'\\}" + }, + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "type": "text", + "content": ", and (b) illustrates the main idea of our dataset synthesis strategy that transfers collected unstable motions " + }, + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "type": "inline_equation", + "content": "\\{F_t^{\\mathrm{ust}}\\}" + }, + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "type": "text", + "content": " to stable video frames " + }, + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "type": "inline_equation", + "content": "\\{I_t^{\\mathrm{stb}}\\}" + }, + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "type": "text", + "content": ", generating synthesized unstable video frames " + }, + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "type": "inline_equation", + "content": "\\{I_t^{\\mathrm{syn}}\\}" + }, + { + "bbox": [ + 46, + 407, + 288, + 475 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "spans": [ + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "inline_equation", + "content": "I_{t - 1}" + }, + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "text", + "content": " with size of " + }, + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "inline_equation", + "content": "640\\times 360" + }, + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "text", + "content": " we estimate " + }, + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "inline_equation", + "content": "F_{t}" + }, + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "text", + "content": " by model [39] (Fig. 3 (a), upper yellow part). Repeat this process, we accumulate a set of inter-frame motions, " + }, + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "inline_equation", + "content": "\\{F_t\\}_{r - 1} = \\langle F_{t - r + 1},\\dots ,F_{t - 1},F_t\\rangle" + }, + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "text", + "content": " . In particular, we keep the most recent " + }, + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "inline_equation", + "content": "r - 1" + }, + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "text", + "content": " motions in our buffer, where historical motions that are beyond range " + }, + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "inline_equation", + "content": "r - 1" + }, + { + "bbox": [ + 47, + 493, + 287, + 577 + ], + "type": "text", + "content": " are simply dropped. The deep meshflow motion estimation is defined as:" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 119, + 585, + 287, + 598 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 119, + 585, + 287, + 598 + ], + "spans": [ + { + "bbox": [ + 119, + 585, + 287, + 598 + ], + "type": "interline_equation", + "content": "F _ {t} = \\downarrow_ {s} \\mathcal {M} _ {F} \\left(I _ {t}, I _ {t - 1}\\right), \\tag {3}", + "image_path": "23b96c843bec753393f26ef9ce37121aafdfd82e1b9e6074c6a8a7bf1b07f192.jpg" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "spans": [ + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "type": "inline_equation", + "content": "\\mathcal{M}_F(\\cdot)" + }, + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "type": "text", + "content": " is the pre-trained deep meshflow model. " + }, + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "type": "inline_equation", + "content": "\\downarrow_{s}" + }, + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "type": "text", + "content": " indicates that we collect the sparse motions at the mesh vertexes, and shrink them pixel by pixel to form a downsampled dense motion field, for the purpose of feeding it to the CNNs. The scale factor " + }, + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "type": "text", + "content": " is set to 8, and the size of the dense motion field " + }, + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "type": "inline_equation", + "content": "F_{t}" + }, + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "type": "text", + "content": " is " + }, + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "type": "inline_equation", + "content": "80\\times 45" + }, + { + "bbox": [ + 46, + 605, + 287, + 677 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 689, + 287, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 689, + 287, + 715 + ], + "spans": [ + { + "bbox": [ + 46, + 689, + 287, + 715 + ], + "type": "text", + "content": "Camera Path Smooth Network Given the estimated camera motion " + }, + { + "bbox": [ + 46, + 689, + 287, + 715 + ], + "type": "inline_equation", + "content": "\\{F_t\\}_{r - 1}" + }, + { + "bbox": [ + 46, + 689, + 287, + 715 + ], + "type": "text", + "content": " as input, the camera path smooth net" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 316, + 545, + 413 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 316, + 545, + 413 + ], + "spans": [ + { + "bbox": [ + 304, + 316, + 545, + 413 + ], + "type": "text", + "content": "work predicts the target smoothed warp field " + }, + { + "bbox": [ + 304, + 316, + 545, + 413 + ], + "type": "inline_equation", + "content": "B_{t}^{\\prime}" + }, + { + "bbox": [ + 304, + 316, + 545, + 413 + ], + "type": "text", + "content": " as Eq. 2. Note that, the meshflow model is spatially-variant, and so does the " + }, + { + "bbox": [ + 304, + 316, + 545, + 413 + ], + "type": "inline_equation", + "content": "F_{t}" + }, + { + "bbox": [ + 304, + 316, + 545, + 413 + ], + "type": "text", + "content": ". Therefore, we provide spatial and temporal optimizations. The camera path smooth network is designed as an encoder-decoder architecture and we implement it as a 4-stage UNet with channels of 64, 128, 256, and 512. We further employ the channel attention mechanism (CA) [9] to adaptively learn the weights of different historical motions." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 425, + 545, + 485 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 425, + 545, + 485 + ], + "spans": [ + { + "bbox": [ + 304, + 425, + 545, + 485 + ], + "type": "text", + "content": "Steady Frame Rendering After obtaining the warp field " + }, + { + "bbox": [ + 304, + 425, + 545, + 485 + ], + "type": "inline_equation", + "content": "B_{t}^{\\prime}" + }, + { + "bbox": [ + 304, + 425, + 545, + 485 + ], + "type": "text", + "content": ", we inverse the process of shrinking, where we put the motions back to the sparse vertex locations to create a mesh, based on which we warp the shaky frame " + }, + { + "bbox": [ + 304, + 425, + 545, + 485 + ], + "type": "inline_equation", + "content": "I_{t}" + }, + { + "bbox": [ + 304, + 425, + 545, + 485 + ], + "type": "text", + "content": " to its stabilized position " + }, + { + "bbox": [ + 304, + 425, + 545, + 485 + ], + "type": "inline_equation", + "content": "I_{t}^{\\prime}" + }, + { + "bbox": [ + 304, + 425, + 545, + 485 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 391, + 495, + 545, + 510 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 391, + 495, + 545, + 510 + ], + "spans": [ + { + "bbox": [ + 391, + 495, + 545, + 510 + ], + "type": "interline_equation", + "content": "I _ {t} ^ {\\prime} = \\mathcal {W} \\left(I _ {t}, B _ {t} ^ {\\prime}\\right), \\tag {4}", + "image_path": "af7f3a76217c9ec96190f3c70f32d617e1e81897c7ffcef485eb3c524f57ac00.jpg" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 304, + 518, + 545, + 544 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 518, + 545, + 544 + ], + "spans": [ + { + "bbox": [ + 304, + 518, + 545, + 544 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 304, + 518, + 545, + 544 + ], + "type": "inline_equation", + "content": "\\mathcal{W}(\\cdot)" + }, + { + "bbox": [ + 304, + 518, + 545, + 544 + ], + "type": "text", + "content": " denotes the backward warping function. The first parameter is an image and the second is a warp field." + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 306, + 551, + 408, + 563 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 551, + 408, + 563 + ], + "spans": [ + { + "bbox": [ + 306, + 551, + 408, + 563 + ], + "type": "text", + "content": "3.3. Training Dataset" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 304, + 570, + 545, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 570, + 545, + 653 + ], + "spans": [ + { + "bbox": [ + 304, + 570, + 545, + 653 + ], + "type": "text", + "content": "Existing training datasets are either captured simultaneously by two cameras [33] or synthesized by simulated injected noise [10, 29, 11]. The former would naturally suffer from parallax problems, while the latter makes the synthesized video paths unrealistic. To address this issue, we offer a novel synthetic method that can build realistic unstable/stable motion pairs from existing shaky videos." + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": "Our main idea is to transfer the motion of an unstable shaky video " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{ust}}" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": " to a stable video " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{stb}}" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": ", yielding another synthesized shaky video " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{syn}}" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": " with motions from " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{ust}}" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": " but image contents as " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{stb}}" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": ". The videos " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{ust}}" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{stb}}" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": " are irrelevant. Let's denote " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\{I_t^{\\mathrm{ust}}\\}" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\{I_t^{\\mathrm{stb}}\\}" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "inline_equation", + "content": "\\{I_t^{\\mathrm{syn}}\\}" + }, + { + "bbox": [ + 304, + 654, + 547, + 715 + ], + "type": "text", + "content": " as video frames and" + } + ] + } + ], + "index": 17 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23033" + } + ] + } + ], + "index": 18 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 3 + }, + { + "para_blocks": [ + { + "bbox": [ + 47, + 71, + 286, + 96 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 71, + 286, + 96 + ], + "spans": [ + { + "bbox": [ + 47, + 71, + 286, + 96 + ], + "type": "inline_equation", + "content": "\\{F_t^{\\mathrm{ust}}\\} ,\\{F_t^{\\mathrm{stb}}\\} ,\\{F_t^{\\mathrm{syn}}\\}" + }, + { + "bbox": [ + 47, + 71, + 286, + 96 + ], + "type": "text", + "content": " as motion between frames of video " + }, + { + "bbox": [ + 47, + 71, + 286, + 96 + ], + "type": "inline_equation", + "content": "\\mathbf{V}_{\\mathrm{ust}},\\mathbf{V}_{\\mathrm{stb}},\\mathbf{V}_{\\mathrm{syn}}" + }, + { + "bbox": [ + 47, + 71, + 286, + 96 + ], + "type": "text", + "content": " accordingly." + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "spans": [ + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "text", + "content": "To achieve this, we first estimate the motions " + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "inline_equation", + "content": "\\{F_t^{\\mathrm{ust}}\\}" + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "inline_equation", + "content": "\\{F_t^{\\mathrm{stb}}\\}" + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "text", + "content": " between adjacent frames of " + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{ust}}" + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{stb}}" + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "text", + "content": " by deep meshflow [39]. Next, we warp the frame " + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "inline_equation", + "content": "\\{I_t^{\\mathrm{stb}}\\}" + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "text", + "content": " by motion " + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "inline_equation", + "content": "\\{F_t^{\\mathrm{ust}}\\}" + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "text", + "content": " to produce " + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "inline_equation", + "content": "\\{I_t^{\\mathrm{syn}}\\}" + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "text", + "content": ", for each timestamp " + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 47, + 96, + 286, + 145 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 123, + 149, + 286, + 163 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 123, + 149, + 286, + 163 + ], + "spans": [ + { + "bbox": [ + 123, + 149, + 286, + 163 + ], + "type": "interline_equation", + "content": "I _ {t} ^ {\\text {s y n}} = \\mathcal {W} \\left(I _ {t} ^ {\\text {s t b}}, F _ {t} ^ {\\text {u s t}}\\right). \\tag {5}", + "image_path": "69e083b7b1c361a566a8d973175e7529fb544f89fc1d601d61105378644663fe.jpg" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "spans": [ + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "type": "text", + "content": "Applying Eq. 5 to every frame of " + }, + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{stb}}" + }, + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "type": "text", + "content": " creates the desired " + }, + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{syn}}" + }, + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "type": "text", + "content": ". The " + }, + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{stb}}" + }, + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{syn}}" + }, + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "type": "text", + "content": " become a pair of stable/unstable videos, where the following motion equality holds (Please refer to Fig. 3 (b) for the relation), for each timestamp " + }, + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "type": "inline_equation", + "content": "t" + }, + { + "bbox": [ + 47, + 169, + 286, + 217 + ], + "type": "text", + "content": ":" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 110, + 233, + 286, + 247 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 233, + 286, + 247 + ], + "spans": [ + { + "bbox": [ + 110, + 233, + 286, + 247 + ], + "type": "interline_equation", + "content": "F _ {t} ^ {\\text {u s t}} + F _ {t} ^ {\\text {s y n}} = F _ {t} ^ {\\text {s t b}} + F _ {t - 1} ^ {\\text {u s t}}, \\tag {6}", + "image_path": "c28eed0fee104be911ec1b69fba54344a239d8cde1d427bc7d45898ba5617042.jpg" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 254, + 286, + 278 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 254, + 286, + 278 + ], + "spans": [ + { + "bbox": [ + 47, + 254, + 286, + 278 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 254, + 286, + 278 + ], + "type": "inline_equation", + "content": "F_{t}^{\\mathrm{ust}}" + }, + { + "bbox": [ + 47, + 254, + 286, + 278 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 47, + 254, + 286, + 278 + ], + "type": "inline_equation", + "content": "F_{t}^{\\mathrm{stb}}" + }, + { + "bbox": [ + 47, + 254, + 286, + 278 + ], + "type": "text", + "content": " have been calculated which are known. Therefore, " + }, + { + "bbox": [ + 47, + 254, + 286, + 278 + ], + "type": "inline_equation", + "content": "F_{t}^{\\mathrm{syn}}" + }, + { + "bbox": [ + 47, + 254, + 286, + 278 + ], + "type": "text", + "content": " can be calculated as:" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 110, + 283, + 286, + 297 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 283, + 286, + 297 + ], + "spans": [ + { + "bbox": [ + 110, + 283, + 286, + 297 + ], + "type": "interline_equation", + "content": "F _ {t} ^ {\\text {s y n}} = F _ {t} ^ {\\text {s t b}} + F _ {t - 1} ^ {\\text {u s t}} - F _ {t} ^ {\\text {u s t}}. \\tag {7}", + "image_path": "b1651392459ce4cfdf82d3375b70cd9b5792418b367c375ff655c452fb16fdce.jpg" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "spans": [ + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "type": "text", + "content": "During the training, our network takes a subset of motions " + }, + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "type": "inline_equation", + "content": "\\{F_t^{\\mathrm{syn}}\\}_{r - 1} = \\langle F_{t - r + 1}^{\\mathrm{syn}},\\dots ,F_{t - 1}^{\\mathrm{syn}},F_t^{\\mathrm{syn}}\\rangle" + }, + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "type": "text", + "content": " as input and output a motion field that is as close as the ground-truth label " + }, + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "type": "inline_equation", + "content": "-F_{t}^{\\mathrm{ust}}" + }, + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "type": "text", + "content": ", which is the inverse motion of " + }, + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "type": "inline_equation", + "content": "F_{t}^{\\mathrm{ust}}" + }, + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "type": "text", + "content": " as shown in Fig. 3 (b). On the other hand, the generated videos " + }, + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{stb}}" + }, + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "type": "inline_equation", + "content": "V_{\\mathrm{syn}}" + }, + { + "bbox": [ + 47, + 303, + 286, + 386 + ], + "type": "text", + "content": " are not important, as all we need are motions that can be calculated and derived by relations." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 46, + 387, + 286, + 529 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 387, + 286, + 529 + ], + "spans": [ + { + "bbox": [ + 46, + 387, + 286, + 529 + ], + "type": "text", + "content": "To further establish the training dataset, we collected 110 stable videos of five categories (including regular, rotation, zooming, parallax, and crowd) using a cell phone mounted on a hand-held physical stabilizer. Next, we collected over 150 unstable videos from the website. Subsequently, we performed data synthesis on the collected stable and unstable videos by employing the aforementioned method, constructing the MotionStab dataset, which contains paired unstable/stable camera motion of various complex scenarios. As illustrated in Fig. 1 (b), the camera path of the synthesized video pairs is well-registered and realistic as the original unstable one." + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 47, + 536, + 134, + 548 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 536, + 134, + 548 + ], + "spans": [ + { + "bbox": [ + 47, + 536, + 134, + 548 + ], + "type": "text", + "content": "3.4. Training Loss" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 46, + 555, + 286, + 625 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 555, + 286, + 625 + ], + "spans": [ + { + "bbox": [ + 46, + 555, + 286, + 625 + ], + "type": "text", + "content": "To train the camera path smooth network, we define several losses in our framework: the motion-consistency loss for maintaining motion continuity between consecutive frames, the shape-consistency loss for preserving the geometry of the predicted warp field, and the scale-preserving loss for maintaining the scale of the predicted warp field." + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 46, + 638, + 286, + 685 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 638, + 286, + 685 + ], + "spans": [ + { + "bbox": [ + 46, + 638, + 286, + 685 + ], + "type": "text", + "content": "Motion-consistency Loss To keep the continuity of the predicted consecutive video frames, the inter-frame motion of the stabilized video " + }, + { + "bbox": [ + 46, + 638, + 286, + 685 + ], + "type": "inline_equation", + "content": "F_{t}^{\\prime}" + }, + { + "bbox": [ + 46, + 638, + 286, + 685 + ], + "type": "text", + "content": " should be as similar as the ground truth one " + }, + { + "bbox": [ + 46, + 638, + 286, + 685 + ], + "type": "inline_equation", + "content": "\\hat{F}_{t}" + }, + { + "bbox": [ + 46, + 638, + 286, + 685 + ], + "type": "text", + "content": ", i.e.," + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 123, + 689, + 286, + 711 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 123, + 689, + 286, + 711 + ], + "spans": [ + { + "bbox": [ + 123, + 689, + 286, + 711 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {M C}} = \\left\\| F _ {t} ^ {\\prime} - \\hat {F} _ {t} \\right\\| _ {1}. \\tag {8}", + "image_path": "bca0daf69274cfe99c60251ca7086e51726c48fdd99f5a90f913d86869202e95.jpg" + } + ] + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 317, + 72, + 402, + 153 + ], + "blocks": [ + { + "bbox": [ + 317, + 72, + 402, + 153 + ], + "lines": [ + { + "bbox": [ + 317, + 72, + 402, + 153 + ], + "spans": [ + { + "bbox": [ + 317, + 72, + 402, + 153 + ], + "type": "image", + "image_path": "ccab14db126c57c99f19b50482e43e9ef3f584284a2bcb2dd441266bdb5645c7.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 320, + 156, + 402, + 168 + ], + "lines": [ + { + "bbox": [ + 320, + 156, + 402, + 168 + ], + "spans": [ + { + "bbox": [ + 320, + 156, + 402, + 168 + ], + "type": "text", + "content": "(a) original meshgrid" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_caption" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 441, + 72, + 527, + 153 + ], + "blocks": [ + { + "bbox": [ + 441, + 72, + 527, + 153 + ], + "lines": [ + { + "bbox": [ + 441, + 72, + 527, + 153 + ], + "spans": [ + { + "bbox": [ + 441, + 72, + 527, + 153 + ], + "type": "image", + "image_path": "0dacd8306a21dc7955c540c2d9e5ce04a38030ed242a14520c6b1128ef5d50dd.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 438, + 156, + 537, + 167 + ], + "lines": [ + { + "bbox": [ + 438, + 156, + 537, + 167 + ], + "spans": [ + { + "bbox": [ + 438, + 156, + 537, + 167 + ], + "type": "text", + "content": "(b) transformed meshgrid" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 305, + 171, + 545, + 213 + ], + "lines": [ + { + "bbox": [ + 305, + 171, + 545, + 213 + ], + "spans": [ + { + "bbox": [ + 305, + 171, + 545, + 213 + ], + "type": "text", + "content": "Figure 4. Illustration of the shape-consistency loss and the scale-preserving loss. The shape-consistency loss is employed to preserve the geometry shape of a meshgrid and the scale-preserving loss is used to maintain the scale." + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_caption" + } + ], + "index": 15 + }, + { + "bbox": [ + 306, + 232, + 545, + 255 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 232, + 545, + 255 + ], + "spans": [ + { + "bbox": [ + 306, + 232, + 545, + 255 + ], + "type": "text", + "content": "According to the relationship of Fig. 3 (a), Eq. 8 can be written as" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 314, + 261, + 545, + 305 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 314, + 261, + 545, + 305 + ], + "spans": [ + { + "bbox": [ + 314, + 261, + 545, + 305 + ], + "type": "interline_equation", + "content": "\\begin{array}{l} \\mathcal {L} _ {\\mathrm {M C}} = \\left\\| \\left(F _ {t} + B _ {t - 1} ^ {\\prime} - B _ {t} ^ {\\prime}\\right) - \\left(F _ {t} + \\hat {B} _ {t - 1} - \\hat {B} _ {t}\\right) \\right\\| _ {1} (9) \\\\ = \\left\\| B _ {t - 1} ^ {\\prime} - B _ {t} ^ {\\prime} - \\hat {B} _ {t - 1} + \\hat {B} _ {t} \\right\\| _ {1}, (10) \\\\ \\end{array}", + "image_path": "f1a062613f8420e8819d7e6ccf04f2589c59fe3ebaf80845b062e719184416b6.jpg" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 305, + 315, + 545, + 351 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 315, + 545, + 351 + ], + "spans": [ + { + "bbox": [ + 305, + 315, + 545, + 351 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 315, + 545, + 351 + ], + "type": "inline_equation", + "content": "B_{t}^{\\prime}" + }, + { + "bbox": [ + 305, + 315, + 545, + 351 + ], + "type": "text", + "content": " denotes network output of the predicted warp field. That is to say, the motion continuity can be restrained by the ground truth warp field " + }, + { + "bbox": [ + 305, + 315, + 545, + 351 + ], + "type": "inline_equation", + "content": "\\hat{B}_{t}" + }, + { + "bbox": [ + 305, + 315, + 545, + 351 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 305, + 315, + 545, + 351 + ], + "type": "inline_equation", + "content": "\\hat{B}_{t - 1}" + }, + { + "bbox": [ + 305, + 315, + 545, + 351 + ], + "type": "text", + "content": "." + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 305, + 363, + 545, + 411 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 363, + 545, + 411 + ], + "spans": [ + { + "bbox": [ + 305, + 363, + 545, + 411 + ], + "type": "text", + "content": "Shape-consistency Loss The shape-consistency loss is effective to prevent the distortion problem of the predicted warp field. Following Wang et al. [33], we implement the SC loss as an intra-grid loss term and an inter-grid loss term:" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 382, + 432, + 545, + 444 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 382, + 432, + 545, + 444 + ], + "spans": [ + { + "bbox": [ + 382, + 432, + 545, + 444 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {S C}} = \\mathcal {L} _ {\\text {i n t r a}} + \\mathcal {L} _ {\\text {i n t e r}}. \\tag {11}", + "image_path": "d9895742b4da3d9e0bc99f147f8b11f10b3eecd91fbd75711324406c1c05aa28.jpg" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 305, + 453, + 545, + 488 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 453, + 545, + 488 + ], + "spans": [ + { + "bbox": [ + 305, + 453, + 545, + 488 + ], + "type": "text", + "content": "Note that each pixel of our dense warp field is actually a vertex of the mesh grid. As depicted in Fig. 4, the intra-grid loss term is defined as:" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 341, + 495, + 545, + 524 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 341, + 495, + 545, + 524 + ], + "spans": [ + { + "bbox": [ + 341, + 495, + 545, + 524 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {i n t r a}} = \\frac {1}{N} \\sum_ {v _ {i}} \\left\\| \\left(v _ {i} ^ {1} - v _ {i}\\right) \\cdot \\left(v _ {i} ^ {2} - v _ {i}\\right) \\right\\| _ {1}, \\tag {12}", + "image_path": "048c36ee1d340b8910306bd71990476c2d1d7144fa2a73e40423d754daf5b71c.jpg" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 305, + 532, + 545, + 567 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 532, + 545, + 567 + ], + "spans": [ + { + "bbox": [ + 305, + 532, + 545, + 567 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 305, + 532, + 545, + 567 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 305, + 532, + 545, + 567 + ], + "type": "text", + "content": " denotes the " + }, + { + "bbox": [ + 305, + 532, + 545, + 567 + ], + "type": "inline_equation", + "content": "i" + }, + { + "bbox": [ + 305, + 532, + 545, + 567 + ], + "type": "text", + "content": "-th vertex and " + }, + { + "bbox": [ + 305, + 532, + 545, + 567 + ], + "type": "inline_equation", + "content": "N" + }, + { + "bbox": [ + 305, + 532, + 545, + 567 + ], + "type": "text", + "content": " is the total number of vertices. Besides, the inter-grid loss term is used to maintain the geometric consistency of adjacent grids:" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 330, + 575, + 545, + 604 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 330, + 575, + 545, + 604 + ], + "spans": [ + { + "bbox": [ + 330, + 575, + 545, + 604 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\text {i n t e r}} = \\frac {1}{N} \\sum_ {v _ {i}} \\left\\| \\left(v _ {i} ^ {1} - v _ {i}\\right) - \\left(v _ {i} - v _ {i} ^ {3}\\right) \\right\\| _ {1}. \\tag {13}", + "image_path": "d8115d84c7c93c79492a303b5fafea14fc13bf4d9151b5b8a35fdfe081496126.jpg" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 305, + 612, + 545, + 660 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 612, + 545, + 660 + ], + "spans": [ + { + "bbox": [ + 305, + 612, + 545, + 660 + ], + "type": "text", + "content": "Scale-preserving Loss Since we convert the sparse motions at the mesh vertexes as a dense motion field and predict the mesh warp field, we introduce a scale-preserving loss to maintain the scale consistency of the predicted warp field:" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 352, + 677, + 545, + 711 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 352, + 677, + 545, + 711 + ], + "spans": [ + { + "bbox": [ + 352, + 677, + 545, + 711 + ], + "type": "interline_equation", + "content": "\\mathcal {L} _ {\\mathrm {S P}} = \\frac {1}{N} \\sum_ {v _ {i}} \\left\\| \\frac {\\left\\| v _ {i} ^ {1} - v _ {i} \\right\\| _ {2}}{s} - 1 \\right\\| _ {1}. \\tag {14}", + "image_path": "82ae4d46424c9e77658ad90046f02ba1ad1ccc46365d133bdb862ca0a04d605a.jpg" + } + ] + } + ], + "index": 28 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23034" + } + ] + } + ], + "index": 29 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 4 + }, + { + "para_blocks": [ + { + "type": "table", + "bbox": [ + 61, + 102, + 535, + 362 + ], + "blocks": [ + { + "bbox": [ + 47, + 69, + 545, + 102 + ], + "lines": [ + { + "bbox": [ + 47, + 69, + 545, + 102 + ], + "spans": [ + { + "bbox": [ + 47, + 69, + 545, + 102 + ], + "type": "text", + "content": "Table 1. Quantitative comparisons on the NUS dataset [25]. We use the Cropping ratio (C), the Distortion value (D), and the Stability score (S) as evaluation metrics. All of these metrics are in the range of 0 to 1, and the higher the better. The " + }, + { + "bbox": [ + 47, + 69, + 545, + 102 + ], + "type": "inline_equation", + "content": "*" + }, + { + "bbox": [ + 47, + 69, + 545, + 102 + ], + "type": "text", + "content": " denotes the results of Bundled [25] are computed directly from the NUS dataset. The bests are marked in red and the second bests are in blue." + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 61, + 102, + 535, + 362 + ], + "lines": [ + { + "bbox": [ + 61, + 102, + 535, + 362 + ], + "spans": [ + { + "bbox": [ + 61, + 102, + 535, + 362 + ], + "type": "table", + "html": "
MethodsRegularRotationZooming
CDSCDSCDS
Offline* Bundled [25]0.66580.94090.90480.64770.86920.91940.57730.90730.9236
Robust L1 [5]0.71570.92520.84540.72060.82310.86170.71070.83290.7730
DIFRINT [1]0.98540.95550.81770.94130.88130.87010.95280.85310.8763
Yu et al. [41]0.94860.97520.84270.76610.76160.93170.89710.86300.9107
PWStableNet [43]0.93190.98520.81620.88010.97070.92510.93030.97920.8906
DUT [36]0.94850.96000.87170.76090.69400.92030.89860.86060.9221
OnlineMeshflow [22]0.80810.91680.83860.75780.76790.90920.77730.87150.8839
StabNet [33]0.74910.83930.84060.74170.72050.83840.73760.78070.8697
Ours0.94330.99170.80300.90210.98470.93410.91850.97360.8982
MethodsCrowdParallaxAvg.
CDSCDSCDS
Offline* Bundled [25]0.66850.89100.87440.71580.89650.89640.65500.90100.9037
Robust L1 [5]0.72080.90770.85040.71320.80540.87780.71620.85890.8417
DIFRINT [1]0.96620.87130.84560.97460.88230.86000.96410.88870.8539
Yu et al. [41]0.90810.91910.86600.92090.92190.88960.88820.88720.8881
PWStableNet [43]0.91810.97900.81620.92440.98020.85490.91700.97890.8606
DUT [36]0.89860.86170.90420.92540.87740.91270.88600.85070.9062
OnlineMeshflow [22]0.78880.82460.82800.81210.84290.84880.78820.87620.8617
StabNet [33]0.72470.77250.79120.69670.76600.82890.72800.77580.8338
Ours0.92470.98160.84080.93260.98270.87620.92420.98290.8705
", + "image_path": "d98bda1901f3c835371268bfc98eb183cb3f208ab5d3aa6e70e4733d7c22f987.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "table_body" + } + ], + "index": 1 + }, + { + "bbox": [ + 47, + 376, + 287, + 400 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 376, + 287, + 400 + ], + "spans": [ + { + "bbox": [ + 47, + 376, + 287, + 400 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 376, + 287, + 400 + ], + "type": "inline_equation", + "content": "s" + }, + { + "bbox": [ + 47, + 376, + 287, + 400 + ], + "type": "text", + "content": " is the scale factor in Eq. 3. Eventually, the overall loss is the combination of the above three loss terms:" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 110, + 411, + 287, + 425 + ], + "type": "interline_equation", + "angle": 0, + "lines": [ + { + "bbox": [ + 110, + 411, + 287, + 425 + ], + "spans": [ + { + "bbox": [ + 110, + 411, + 287, + 425 + ], + "type": "interline_equation", + "content": "\\mathcal {L} = \\mathcal {L} _ {\\mathrm {M C}} + \\alpha \\mathcal {L} _ {\\mathrm {S C}} + \\beta \\mathcal {L} _ {\\mathrm {S P}}, \\tag {15}", + "image_path": "3666d8d43b1040507f9485e8a54fb100d490302ad533bfbc187571956c84d522.jpg" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 47, + 434, + 218, + 447 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 434, + 218, + 447 + ], + "spans": [ + { + "bbox": [ + 47, + 434, + 218, + 447 + ], + "type": "text", + "content": "where " + }, + { + "bbox": [ + 47, + 434, + 218, + 447 + ], + "type": "inline_equation", + "content": "\\alpha" + }, + { + "bbox": [ + 47, + 434, + 218, + 447 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 47, + 434, + 218, + 447 + ], + "type": "inline_equation", + "content": "\\beta" + }, + { + "bbox": [ + 47, + 434, + 218, + 447 + ], + "type": "text", + "content": " are empirically set to 0.01." + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 47, + 458, + 173, + 472 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 458, + 173, + 472 + ], + "spans": [ + { + "bbox": [ + 47, + 458, + 173, + 472 + ], + "type": "text", + "content": "4. Experimental Results" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 47, + 479, + 180, + 491 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 479, + 180, + 491 + ], + "spans": [ + { + "bbox": [ + 47, + 479, + 180, + 491 + ], + "type": "text", + "content": "4.1. Implementation Details" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 46, + 498, + 287, + 689 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 498, + 287, + 689 + ], + "spans": [ + { + "bbox": [ + 46, + 498, + 287, + 689 + ], + "type": "text", + "content": "Evaluation Metrics For quantitative comparison, we employ three widely used metrics: cropping ratio, distortion value, and stability score, as in prior methods [25, 36, 43, 22]. For cropping ratio and distortion value, we first fit a global homography between the input and output videos at each frame. The cropping ratio measures the remaining frame area after cropping out undefined pixels due to motion compensation and is computed as the average scale component of the entire video. The distortion value, which is defined as the worst ratio of the two largest eigenvalues of the affine component across all frames, measures the anisotropic scaling of the homography between the input and output frames. The stability score measures the smoothness of the stabilized videos and the camera path is utilized to determine the value. We compute this metric by using a frequency domain analysis as in Bundled [25]." + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 47, + 689, + 287, + 714 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 47, + 689, + 287, + 714 + ], + "spans": [ + { + "bbox": [ + 47, + 689, + 287, + 714 + ], + "type": "text", + "content": "Implementation Details Our network is implemented by PyTorch. We use Adam as the optimizer for training, with" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "spans": [ + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "type": "text", + "content": "an initial learning rate of " + }, + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "type": "inline_equation", + "content": "1 \\times 10^{-4}" + }, + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "type": "text", + "content": " and no weight decay. We set " + }, + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "type": "inline_equation", + "content": "\\beta_{1} = 0.9" + }, + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "type": "text", + "content": ", " + }, + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "type": "inline_equation", + "content": "\\beta_{2} = 0.999" + }, + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "type": "text", + "content": ", and " + }, + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "type": "inline_equation", + "content": "\\epsilon = 1e - 8" + }, + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "type": "text", + "content": ", respectively. We train the network for 100,000 iterations. The overall training time on two NVIDIA 1080Ti GPUs is 20 hours. During training, two adjacent frames and their corresponding historical frames are selected as a training sample. The MotionStab dataset comprises 65238 training samples in total. For inference, the overall framework can process a frame of size " + }, + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "type": "inline_equation", + "content": "640 \\times 360" + }, + { + "bbox": [ + 304, + 376, + 545, + 509 + ], + "type": "text", + "content": " in real-time. Specifically, we spend 12 ms, 10 ms, and 4 ms to extract camera motion, smooth the camera path, and synthesize stable frames, respectively." + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 305, + 515, + 499, + 529 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 515, + 499, + 529 + ], + "spans": [ + { + "bbox": [ + 305, + 515, + 499, + 529 + ], + "type": "text", + "content": "4.2. Comparisons with Existing Methods" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 304, + 534, + 545, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 534, + 545, + 653 + ], + "spans": [ + { + "bbox": [ + 304, + 534, + 545, + 653 + ], + "type": "text", + "content": "To evaluate the proposed approach, we compare it with the state-of-the-art methods on the NUS dataset [25]. The compared methods include three traditional methods, Bundled [25], Robust L1 [5], Meshflow [22], and five deep learning based methods, DIFRINT [1], Yu et al. [41], PW-StableNet [43], DUT [36], and StabNet [33]. It is worth noting that Meshflow [22], StabNet [33], and ours are online, while the rest are offline. The results of the compared methods are obtained from publicly accessible implementations with default parameters or pre-trained models." + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": "Quantitative results Table 1 presents the quantitative results for each of the five categories (including regular, quick rotation, zooming, crowd, and parallax), as well as the average results across all categories. From Table 1, we can see that offline approaches generally outperform online meth" + } + ] + } + ], + "index": 12 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23035" + } + ] + } + ], + "index": 13 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 5 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 63, + 76, + 186, + 140 + ], + "blocks": [ + { + "bbox": [ + 63, + 76, + 186, + 140 + ], + "lines": [ + { + "bbox": [ + 63, + 76, + 186, + 140 + ], + "spans": [ + { + "bbox": [ + 63, + 76, + 186, + 140 + ], + "type": "image", + "image_path": "fad4366167722f0e8f00d9253a521d394314aea67e7394b4858186ae480c2f68.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 187, + 76, + 301, + 140 + ], + "blocks": [ + { + "bbox": [ + 187, + 76, + 301, + 140 + ], + "lines": [ + { + "bbox": [ + 187, + 76, + 301, + 140 + ], + "spans": [ + { + "bbox": [ + 187, + 76, + 301, + 140 + ], + "type": "image", + "image_path": "c50730e5163c7c1520d8fc74f897a652a4ec789c8c85f98aa083bc071fd6685b.jpg" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_body" + } + ], + "index": 1 + }, + { + "type": "image", + "bbox": [ + 301, + 76, + 413, + 140 + ], + "blocks": [ + { + "bbox": [ + 301, + 76, + 413, + 140 + ], + "lines": [ + { + "bbox": [ + 301, + 76, + 413, + 140 + ], + "spans": [ + { + "bbox": [ + 301, + 76, + 413, + 140 + ], + "type": "image", + "image_path": "65109fb838b10a7059575f7946138f2ee89ed90f9da2a7c1b7df202f8c969fa7.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 414, + 76, + 527, + 140 + ], + "blocks": [ + { + "bbox": [ + 414, + 76, + 527, + 140 + ], + "lines": [ + { + "bbox": [ + 414, + 76, + 527, + 140 + ], + "spans": [ + { + "bbox": [ + 414, + 76, + 527, + 140 + ], + "type": "image", + "image_path": "83829c3750c8914f90888cff1ed01f6591cff5bc04fec59cd77ca8aa75d8d0b8.jpg" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_body" + } + ], + "index": 3 + }, + { + "type": "image", + "bbox": [ + 63, + 140, + 186, + 204 + ], + "blocks": [ + { + "bbox": [ + 63, + 140, + 186, + 204 + ], + "lines": [ + { + "bbox": [ + 63, + 140, + 186, + 204 + ], + "spans": [ + { + "bbox": [ + 63, + 140, + 186, + 204 + ], + "type": "image", + "image_path": "88366a8ba0d4a1fcdc386cbf272d4c9c3615ffca85918ff2c5942cc8567479ba.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 187, + 140, + 301, + 204 + ], + "blocks": [ + { + "bbox": [ + 187, + 140, + 301, + 204 + ], + "lines": [ + { + "bbox": [ + 187, + 140, + 301, + 204 + ], + "spans": [ + { + "bbox": [ + 187, + 140, + 301, + 204 + ], + "type": "image", + "image_path": "60e0a64589b2eecc0990ab4c5269fdf7e5ee9c45b0ae2285f02f6e5b459c924d.jpg" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_body" + } + ], + "index": 5 + }, + { + "type": "image", + "bbox": [ + 301, + 140, + 413, + 204 + ], + "blocks": [ + { + "bbox": [ + 301, + 140, + 413, + 204 + ], + "lines": [ + { + "bbox": [ + 301, + 140, + 413, + 204 + ], + "spans": [ + { + "bbox": [ + 301, + 140, + 413, + 204 + ], + "type": "image", + "image_path": "381a2f9486c27f07b408aa52e35e3097591a179010208114301836f30cf987b7.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 414, + 140, + 528, + 204 + ], + "blocks": [ + { + "bbox": [ + 414, + 140, + 528, + 204 + ], + "lines": [ + { + "bbox": [ + 414, + 140, + 528, + 204 + ], + "spans": [ + { + "bbox": [ + 414, + 140, + 528, + 204 + ], + "type": "image", + "image_path": "13fdd79c1779275bf3eb9c30417051cce3f030c050d0a85d99635cc557a46453.jpg" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_body" + } + ], + "index": 7 + }, + { + "type": "image", + "bbox": [ + 63, + 205, + 186, + 268 + ], + "blocks": [ + { + "bbox": [ + 63, + 205, + 186, + 268 + ], + "lines": [ + { + "bbox": [ + 63, + 205, + 186, + 268 + ], + "spans": [ + { + "bbox": [ + 63, + 205, + 186, + 268 + ], + "type": "image", + "image_path": "04d95e27f195da35672408352acd26f2a5ff8f7ae3d9f38ec616f6fb7966f865.jpg" + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_body" + } + ], + "index": 8 + }, + { + "type": "image", + "bbox": [ + 187, + 205, + 301, + 268 + ], + "blocks": [ + { + "bbox": [ + 187, + 205, + 301, + 268 + ], + "lines": [ + { + "bbox": [ + 187, + 205, + 301, + 268 + ], + "spans": [ + { + "bbox": [ + 187, + 205, + 301, + 268 + ], + "type": "image", + "image_path": "b2d602d1818445c7171527dba5e05949126fa2b39b26ba4e222dcfd75b878e51.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + } + ], + "index": 9 + }, + { + "type": "image", + "bbox": [ + 301, + 205, + 413, + 268 + ], + "blocks": [ + { + "bbox": [ + 301, + 205, + 413, + 268 + ], + "lines": [ + { + "bbox": [ + 301, + 205, + 413, + 268 + ], + "spans": [ + { + "bbox": [ + 301, + 205, + 413, + 268 + ], + "type": "image", + "image_path": "7a0995bf53464e9d7c6477dd64210c4a8980e44d0ace36d90a93fc75c407b022.jpg" + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_body" + } + ], + "index": 10 + }, + { + "type": "image", + "bbox": [ + 414, + 205, + 528, + 268 + ], + "blocks": [ + { + "bbox": [ + 414, + 205, + 528, + 268 + ], + "lines": [ + { + "bbox": [ + 414, + 205, + 528, + 268 + ], + "spans": [ + { + "bbox": [ + 414, + 205, + 528, + 268 + ], + "type": "image", + "image_path": "e8226e73869bcad9521925ec46839eb6ee938297c8972d1ddaaeb83828277e1e.jpg" + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "image_body" + } + ], + "index": 11 + }, + { + "type": "image", + "bbox": [ + 63, + 269, + 186, + 331 + ], + "blocks": [ + { + "bbox": [ + 63, + 269, + 186, + 331 + ], + "lines": [ + { + "bbox": [ + 63, + 269, + 186, + 331 + ], + "spans": [ + { + "bbox": [ + 63, + 269, + 186, + 331 + ], + "type": "image", + "image_path": "0da421cc20ae680eeb209c987b9364764d143e1f917f3498a57ca5ee4b6a66ae.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "image_body" + } + ], + "index": 12 + }, + { + "type": "image", + "bbox": [ + 187, + 269, + 301, + 331 + ], + "blocks": [ + { + "bbox": [ + 187, + 269, + 301, + 331 + ], + "lines": [ + { + "bbox": [ + 187, + 269, + 301, + 331 + ], + "spans": [ + { + "bbox": [ + 187, + 269, + 301, + 331 + ], + "type": "image", + "image_path": "1a39b4bc518ba7ce74fbbb8fb127294549ca1c481a9f5e9201eb507fb8d25604.jpg" + } + ] + } + ], + "index": 13, + "angle": 0, + "type": "image_body" + } + ], + "index": 13 + }, + { + "type": "image", + "bbox": [ + 301, + 269, + 413, + 331 + ], + "blocks": [ + { + "bbox": [ + 301, + 269, + 413, + 331 + ], + "lines": [ + { + "bbox": [ + 301, + 269, + 413, + 331 + ], + "spans": [ + { + "bbox": [ + 301, + 269, + 413, + 331 + ], + "type": "image", + "image_path": "ec85eca88e1dfae25eb0b7e6d51c2c8f77d75d56a92d14b2bda9557695c17d7a.jpg" + } + ] + } + ], + "index": 14, + "angle": 0, + "type": "image_body" + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 414, + 269, + 528, + 331 + ], + "blocks": [ + { + "bbox": [ + 414, + 269, + 528, + 331 + ], + "lines": [ + { + "bbox": [ + 414, + 269, + 528, + 331 + ], + "spans": [ + { + "bbox": [ + 414, + 269, + 528, + 331 + ], + "type": "image", + "image_path": "6cb21691cba3f3da6b28b36d2def4409c062445a1558cfbdba448830a30b42d5.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + } + ], + "index": 15 + }, + { + "type": "image", + "bbox": [ + 63, + 332, + 186, + 396 + ], + "blocks": [ + { + "bbox": [ + 63, + 332, + 186, + 396 + ], + "lines": [ + { + "bbox": [ + 63, + 332, + 186, + 396 + ], + "spans": [ + { + "bbox": [ + 63, + 332, + 186, + 396 + ], + "type": "image", + "image_path": "2e2f40175cc13592998b75a7c912b80d99709fb4a8d7ed8b2800a78fa272b88d.jpg" + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 108, + 399, + 152, + 408 + ], + "lines": [ + { + "bbox": [ + 108, + 399, + 152, + 408 + ], + "spans": [ + { + "bbox": [ + 108, + 399, + 152, + 408 + ], + "type": "text", + "content": "(a) Meshflow" + } + ] + } + ], + "index": 20, + "angle": 0, + "type": "image_caption" + } + ], + "index": 16 + }, + { + "type": "image", + "bbox": [ + 187, + 333, + 301, + 396 + ], + "blocks": [ + { + "bbox": [ + 187, + 333, + 301, + 396 + ], + "lines": [ + { + "bbox": [ + 187, + 333, + 301, + 396 + ], + "spans": [ + { + "bbox": [ + 187, + 333, + 301, + 396 + ], + "type": "image", + "image_path": "62a38c98c8b31ae2d7043e5a9456a8dc24d7ed70cc9215cad9e6782595eba3d8.jpg" + } + ] + } + ], + "index": 17, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 225, + 399, + 262, + 408 + ], + "lines": [ + { + "bbox": [ + 225, + 399, + 262, + 408 + ], + "spans": [ + { + "bbox": [ + 225, + 399, + 262, + 408 + ], + "type": "text", + "content": "(b) StabNet" + } + ] + } + ], + "index": 21, + "angle": 0, + "type": "image_caption" + } + ], + "index": 17 + }, + { + "type": "image", + "bbox": [ + 301, + 332, + 413, + 396 + ], + "blocks": [ + { + "bbox": [ + 301, + 332, + 413, + 396 + ], + "lines": [ + { + "bbox": [ + 301, + 332, + 413, + 396 + ], + "spans": [ + { + "bbox": [ + 301, + 332, + 413, + 396 + ], + "type": "image", + "image_path": "5a91124dfbf4cb9f96ae0b55bd2ad6bd6ac6adea671ba7c97b1c4ec461a46b04.jpg" + } + ] + } + ], + "index": 18, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 343, + 399, + 370, + 408 + ], + "lines": [ + { + "bbox": [ + 343, + 399, + 370, + 408 + ], + "spans": [ + { + "bbox": [ + 343, + 399, + 370, + 408 + ], + "type": "text", + "content": "(c) Ours" + } + ] + } + ], + "index": 22, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 46, + 417, + 547, + 440 + ], + "lines": [ + { + "bbox": [ + 46, + 417, + 547, + 440 + ], + "spans": [ + { + "bbox": [ + 46, + 417, + 547, + 440 + ], + "type": "text", + "content": "Figure 5. Qualitative comparisons with the online methods Meshflow [22] and StabNet [33]. We keep the original warped frames for comparison. The red boxes indicate the preserved frame content after cropping. The red arrows highlight the shear and distortion artifacts." + } + ] + } + ], + "index": 24, + "angle": 0, + "type": "image_caption" + } + ], + "index": 18 + }, + { + "type": "image", + "bbox": [ + 414, + 333, + 528, + 396 + ], + "blocks": [ + { + "bbox": [ + 414, + 333, + 528, + 396 + ], + "lines": [ + { + "bbox": [ + 414, + 333, + 528, + 396 + ], + "spans": [ + { + "bbox": [ + 414, + 333, + 528, + 396 + ], + "type": "image", + "image_path": "1b834a7bb0f6e499f22a814e7c9b42ba64e79d41ef64643fe561b73a000b41a3.jpg" + } + ] + } + ], + "index": 19, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 446, + 399, + 495, + 408 + ], + "lines": [ + { + "bbox": [ + 446, + 399, + 495, + 408 + ], + "spans": [ + { + "bbox": [ + 446, + 399, + 495, + 408 + ], + "type": "text", + "content": "(d) Input frame" + } + ] + } + ], + "index": 23, + "angle": 0, + "type": "image_caption" + } + ], + "index": 19 + }, + { + "bbox": [ + 46, + 454, + 287, + 538 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 454, + 287, + 538 + ], + "spans": [ + { + "bbox": [ + 46, + 454, + 287, + 538 + ], + "type": "text", + "content": "ods, especially in challenging scenarios. In comparison to existing online approaches, our method achieves significant performance improvements. Taking Meshflow [22] as the baseline, the cropping ratio and the distortion value of our method increase by " + }, + { + "bbox": [ + 46, + 454, + 287, + 538 + ], + "type": "inline_equation", + "content": "17.25\\%" + }, + { + "bbox": [ + 46, + 454, + 287, + 538 + ], + "type": "text", + "content": " and " + }, + { + "bbox": [ + 46, + 454, + 287, + 538 + ], + "type": "inline_equation", + "content": "12.18\\%" + }, + { + "bbox": [ + 46, + 454, + 287, + 538 + ], + "type": "text", + "content": ", respectively. Notably, our method can achieve approaching results to several compared offline methods." + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 46, + 546, + 288, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 546, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 546, + 288, + 713 + ], + "type": "text", + "content": "Qualitative results Fig. 5 illustrates the flaws that can be noticed directly from the video frames, including shear, distortion, and over-cropping. As can be seen, Meshflow suffers from shear and distortion in some scenes due to its reliance on well-optimized parameter tweaking. The shear and over-cropping problems in StabNet [33] are more severe because they directly employ video frames as input for mixed camera motion estimation and path smoothing, making the performance and generalization ability difficult to even approach the traditional approach Meshflow [22]. On the contrary, since our network solely smooths and optimizes the camera path, regardless of image content, it is more generic on diverse challenging scenes and can avoid the aforementioned issues in an online setting." + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 304, + 454, + 545, + 586 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 454, + 545, + 586 + ], + "spans": [ + { + "bbox": [ + 304, + 454, + 545, + 586 + ], + "type": "text", + "content": "User Study We also conduct a user study comparing our method to the PWStableNet [43], which is one of the deep offline approaches that achieves overall good performances according to Table 1. Note that we do not compare with the online methods [22, 33], because our qualitative results are significantly better than theirs. Specifically, we prepare a test set containing 15 videos (3 videos per category), and each of the 20 participants is asked to choose the better one from the results of the two compared methods. The videos are arranged randomly and the original unstable videos are provided. The results of the user study are shown in Fig. 7." + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 306, + 597, + 406, + 609 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 597, + 406, + 609 + ], + "spans": [ + { + "bbox": [ + 306, + 597, + 406, + 609 + ], + "type": "text", + "content": "4.3. Ablation Studies" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 304, + 616, + 545, + 640 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 616, + 545, + 640 + ], + "spans": [ + { + "bbox": [ + 304, + 616, + 545, + 640 + ], + "type": "text", + "content": "To analyze the capability of each component, we conduct extensive ablation experiments on the NUS dataset [25]." + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 642, + 545, + 713 + ], + "type": "text", + "content": "Ablation on losses We first conduct experiments on the motion-consistency loss, the shape-consistency loss, and the scale-preserving loss. In the first row of Table 2, we take the vanilla UNet optimized by the MC loss as our baseline. In the next two rows, we add the SC loss and the SP loss to train the model, respectively. Comparing the first three rows" + } + ] + } + ], + "index": 30 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 749, + 317, + 757 + ], + "type": "text", + "content": "23036" + } + ] + } + ], + "index": 31 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 6 + }, + { + "para_blocks": [ + { + "type": "image", + "bbox": [ + 63, + 74, + 186, + 205 + ], + "blocks": [ + { + "bbox": [ + 63, + 74, + 186, + 205 + ], + "lines": [ + { + "bbox": [ + 63, + 74, + 186, + 205 + ], + "spans": [ + { + "bbox": [ + 63, + 74, + 186, + 205 + ], + "type": "image", + "image_path": "64c8afe9dfbadb16b77839161c267065890a0ec5e1163b5c8c2a9ec7b805aa12.jpg" + } + ] + } + ], + "index": 0, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 117, + 207, + 141, + 216 + ], + "lines": [ + { + "bbox": [ + 117, + 207, + 141, + 216 + ], + "spans": [ + { + "bbox": [ + 117, + 207, + 141, + 216 + ], + "type": "text", + "content": "(a) MC" + } + ] + } + ], + "index": 1, + "angle": 0, + "type": "image_caption" + } + ], + "index": 0 + }, + { + "type": "image", + "bbox": [ + 187, + 74, + 299, + 205 + ], + "blocks": [ + { + "bbox": [ + 187, + 74, + 299, + 205 + ], + "lines": [ + { + "bbox": [ + 187, + 74, + 299, + 205 + ], + "spans": [ + { + "bbox": [ + 187, + 74, + 299, + 205 + ], + "type": "image", + "image_path": "25102eeddcf1ff26280e87205d00fb675e5528acbbb93ea64ea09470bc0c3bac.jpg" + } + ] + } + ], + "index": 2, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 222, + 206, + 265, + 216 + ], + "lines": [ + { + "bbox": [ + 222, + 206, + 265, + 216 + ], + "spans": [ + { + "bbox": [ + 222, + 206, + 265, + 216 + ], + "type": "text", + "content": "(b) " + }, + { + "bbox": [ + 222, + 206, + 265, + 216 + ], + "type": "inline_equation", + "content": "\\mathrm{MC} + \\mathrm{SC}" + } + ] + } + ], + "index": 3, + "angle": 0, + "type": "image_caption" + } + ], + "index": 2 + }, + { + "type": "image", + "bbox": [ + 301, + 74, + 415, + 205 + ], + "blocks": [ + { + "bbox": [ + 301, + 74, + 415, + 205 + ], + "lines": [ + { + "bbox": [ + 301, + 74, + 415, + 205 + ], + "spans": [ + { + "bbox": [ + 301, + 74, + 415, + 205 + ], + "type": "image", + "image_path": "a8deaeadd0f4f7c601d6edcd408e6d63c0ae2094ca4d0a5c5a8debbe6ffdac98.jpg" + } + ] + } + ], + "index": 4, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 328, + 206, + 388, + 216 + ], + "lines": [ + { + "bbox": [ + 328, + 206, + 388, + 216 + ], + "spans": [ + { + "bbox": [ + 328, + 206, + 388, + 216 + ], + "type": "text", + "content": "(c) " + }, + { + "bbox": [ + 328, + 206, + 388, + 216 + ], + "type": "inline_equation", + "content": "\\mathrm{MC} + \\mathrm{SC} + \\mathrm{SP}" + } + ] + } + ], + "index": 5, + "angle": 0, + "type": "image_caption" + } + ], + "index": 4 + }, + { + "type": "image", + "bbox": [ + 416, + 75, + 530, + 205 + ], + "blocks": [ + { + "bbox": [ + 416, + 75, + 530, + 205 + ], + "lines": [ + { + "bbox": [ + 416, + 75, + 530, + 205 + ], + "spans": [ + { + "bbox": [ + 416, + 75, + 530, + 205 + ], + "type": "image", + "image_path": "2c0799781a198c07c416afed5c74872644e487e34f85418f3219b75a01465e3a.jpg" + } + ] + } + ], + "index": 6, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 447, + 206, + 497, + 216 + ], + "lines": [ + { + "bbox": [ + 447, + 206, + 497, + 216 + ], + "spans": [ + { + "bbox": [ + 447, + 206, + 497, + 216 + ], + "type": "text", + "content": "(d) Input frame" + } + ] + } + ], + "index": 7, + "angle": 0, + "type": "image_caption" + } + ], + "index": 6 + }, + { + "type": "image", + "bbox": [ + 52, + 251, + 282, + 334 + ], + "blocks": [ + { + "bbox": [ + 46, + 220, + 544, + 243 + ], + "lines": [ + { + "bbox": [ + 46, + 220, + 544, + 243 + ], + "spans": [ + { + "bbox": [ + 46, + 220, + 544, + 243 + ], + "type": "text", + "content": "Figure 6. Qualitative results of the ablation study on the motion-consistency loss (MC), the shape-consistency loss (SC), and the scale-preserving loss (SP). The red arrows show the shear and distortion regions, and the red boxes show the preserved frame region." + } + ] + } + ], + "index": 8, + "angle": 0, + "type": "image_caption" + }, + { + "bbox": [ + 52, + 251, + 282, + 334 + ], + "lines": [ + { + "bbox": [ + 52, + 251, + 282, + 334 + ], + "spans": [ + { + "bbox": [ + 52, + 251, + 282, + 334 + ], + "type": "image", + "image_path": "f905e1e70b7356d73df1c698ae13b2ab887c57408811907bcac6877bc2917db8.jpg" + } + ] + } + ], + "index": 9, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 47, + 338, + 278, + 350 + ], + "lines": [ + { + "bbox": [ + 47, + 338, + 278, + 350 + ], + "spans": [ + { + "bbox": [ + 47, + 338, + 278, + 350 + ], + "type": "text", + "content": "Figure 7. User study results comparing with PWStableNet [43]." + } + ] + } + ], + "index": 10, + "angle": 0, + "type": "image_caption" + } + ], + "index": 9 + }, + { + "type": "table", + "bbox": [ + 54, + 382, + 280, + 440 + ], + "blocks": [ + { + "bbox": [ + 47, + 361, + 286, + 382 + ], + "lines": [ + { + "bbox": [ + 47, + 361, + 286, + 382 + ], + "spans": [ + { + "bbox": [ + 47, + 361, + 286, + 382 + ], + "type": "text", + "content": "Table 2. Quantitative results of the ablation studies on the hybrid loss and the channel attention mechanism (CA)." + } + ] + } + ], + "index": 11, + "angle": 0, + "type": "table_caption" + }, + { + "bbox": [ + 54, + 382, + 280, + 440 + ], + "lines": [ + { + "bbox": [ + 54, + 382, + 280, + 440 + ], + "spans": [ + { + "bbox": [ + 54, + 382, + 280, + 440 + ], + "type": "table", + "html": "
MCSCSPCACDS
Baseline✓0.800.840.87
Variant 1✓✓0.850.900.86
Variant 2✓✓✓0.900.950.86
Ours✓✓✓✓0.920.980.87
", + "image_path": "0455e5ecfc083999dae0b47a303329e0c6be62f821c7f8faf0f6bfd55f3bd4bf.jpg" + } + ] + } + ], + "index": 12, + "angle": 0, + "type": "table_body" + } + ], + "index": 12 + }, + { + "bbox": [ + 46, + 460, + 286, + 581 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 460, + 286, + 581 + ], + "spans": [ + { + "bbox": [ + 46, + 460, + 286, + 581 + ], + "type": "text", + "content": "reveals that adding the SC loss and the SP loss respectively improves performance. The best performance is gained by combining them together. Fig. 6 shows some qualitative results. As seen, when only using the MC loss, substantial shear, and distortion occur (Fig. 6 (a), highlighted by red arrows.). The distortion artifacts can be effectively resolved by adding the SC loss (Fig. 6 (b)). However, the scale of the stabilized frame is not well preserved, resulting in larger cropped regions. This issue can eventually be solved by the proposed SP loss (Fig. 6 (c), distinguished by red boxes)." + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "spans": [ + { + "bbox": [ + 46, + 582, + 286, + 713 + ], + "type": "text", + "content": "Analysis of the quality of the dataset To verify the impact of the dataset, we train the network on the DeepStab [33] and our MotionStab dataset, respectively. Fig. 8 shows the quantitative results on the NUS dataset. As seen, when trained using the proposed MotionStab dataset, both our method and StabNet [33] yield better results than training on the DeepStab dataset, respectively, especially in terms of cropping ratio and distortion value. We conclude that the main reasons are twofold. Firstly, our MotionStab dataset contains richer scenarios and unstable motions, improving the performance and generalization ability of the network." + } + ] + } + ], + "index": 14 + }, + { + "type": "image", + "bbox": [ + 318, + 251, + 535, + 367 + ], + "blocks": [ + { + "bbox": [ + 318, + 251, + 535, + 367 + ], + "lines": [ + { + "bbox": [ + 318, + 251, + 535, + 367 + ], + "spans": [ + { + "bbox": [ + 318, + 251, + 535, + 367 + ], + "type": "image", + "image_path": "56e589c53c1accd1e779900014fb03270eda1dd2feec49c09638bd37909f7d9d.jpg" + } + ] + } + ], + "index": 15, + "angle": 0, + "type": "image_body" + }, + { + "bbox": [ + 306, + 372, + 544, + 393 + ], + "lines": [ + { + "bbox": [ + 306, + 372, + 544, + 393 + ], + "spans": [ + { + "bbox": [ + 306, + 372, + 544, + 393 + ], + "type": "text", + "content": "Figure 8. Comparisons of the quantitative results between StabNet [33] and our method when trained with different datasets." + } + ] + } + ], + "index": 16, + "angle": 0, + "type": "image_caption" + } + ], + "index": 15 + }, + { + "bbox": [ + 305, + 404, + 545, + 477 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 305, + 404, + 545, + 477 + ], + "spans": [ + { + "bbox": [ + 305, + 404, + 545, + 477 + ], + "type": "text", + "content": "Secondly, the synthesized pairs in MotionStab suffer no parallax issue inherent in DeepStab, leading to fewer distortion artifacts (i.e., higher distortion value) in the stabilized frames. Additionally, our method outperforms StabNet [33] on both datasets, demonstrating its superiority over directly predicting stable warp fields from input video frames." + } + ] + } + ], + "index": 17 + }, + { + "bbox": [ + 306, + 488, + 383, + 501 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 306, + 488, + 383, + 501 + ], + "spans": [ + { + "bbox": [ + 306, + 488, + 383, + 501 + ], + "type": "text", + "content": "5. Conclusions" + } + ] + } + ], + "index": 18 + }, + { + "bbox": [ + 304, + 509, + 545, + 653 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 509, + 545, + 653 + ], + "spans": [ + { + "bbox": [ + 304, + 509, + 545, + 653 + ], + "type": "text", + "content": "This work presents a deep camera path optimization framework for online video stabilization. We leave the motion estimation to recent off-the-shelf deep motion models and concentrate on path smoothing. Our model takes a 2D camera path in a sliding window as input and outputs a warp field for the last frame in that window. A video can be stabilized online by applying our model repeatedly for every incoming frame. We introduce a hybrid loss to enhance the spatial and temporal consistency of the stabilized video. Moreover, we created a motion dataset to train our model. Results show that our method outperforms previous approaches both qualitatively and quantitatively." + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "angle": 0, + "lines": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 304, + 654, + 545, + 713 + ], + "type": "text", + "content": "Acknowledgements This work was supported by Sichuan Science and Technology Program of China under grants Nos. 2023NSFSC0462, 2023NSFSC1972, 2022YFQ0079, 2021YFG0001, 2022YFG0050, and National Natural Science Foundation of China under grant No.62031009." + } + ] + } + ], + "index": 20 + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23037" + } + ] + } + ], + "index": 21 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 7 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "type": "title", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "spans": [ + { + "bbox": [ + 48, + 71, + 107, + 84 + ], + "type": "text", + "content": "References" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 91, + 288, + 713 + ], + "type": "list", + "angle": 0, + "index": 18, + "blocks": [ + { + "bbox": [ + 53, + 91, + 287, + 124 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 91, + 287, + 124 + ], + "spans": [ + { + "bbox": [ + 53, + 91, + 287, + 124 + ], + "type": "text", + "content": "[1] Jinsoo Choi and In So Kweon. Deep iterative frame interpolation for full-frame video stabilization. ACM Trans. on Graphics (TOG), 39(1):1-9, 2020. 6" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 53, + 125, + 288, + 168 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 125, + 288, + 168 + ], + "spans": [ + { + "bbox": [ + 53, + 125, + 288, + 168 + ], + "type": "text", + "content": "[2] Michael L Gleicher and Feng Liu. Re-cinematography: Improving the camerawork of casual video. ACM transactions on multimedia computing, communications, and applications (TOMM), 5(1):1-28, 2008. 2" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 53, + 171, + 288, + 203 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 171, + 288, + 203 + ], + "spans": [ + { + "bbox": [ + 53, + 171, + 288, + 203 + ], + "type": "text", + "content": "[3] Amit Goldstein and Raanan Fattal. Video stabilization using epipolar geometry. ACM Trans. on Graphics (TOG), 31(5):1-10, 2012. 1, 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 53, + 205, + 288, + 237 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 205, + 288, + 237 + ], + "spans": [ + { + "bbox": [ + 53, + 205, + 288, + 237 + ], + "type": "text", + "content": "[4] Matthias Grundmann, Vivek Kwatra, Daniel Castro, and Irfan Essa. Calibration-free rolling shutter removal. In Proc. ICCP, pages 1-8, 2012. 2, 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 53, + 239, + 288, + 271 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 239, + 288, + 271 + ], + "spans": [ + { + "bbox": [ + 53, + 239, + 288, + 271 + ], + "type": "text", + "content": "[5] Matthias Grundmann, Vivek Kwatra, and Irfan Essa. Autodirected video stabilization with robust 11 optimal camera paths. In Proc. CVPR, pages 225-232, 2011. 1, 2, 6" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 53, + 273, + 288, + 316 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 273, + 288, + 316 + ], + "spans": [ + { + "bbox": [ + 53, + 273, + 288, + 316 + ], + "type": "text", + "content": "[6] Wilko Guilluy, Laurent Oudre, and Azedine Beghdadi. Video stabilization: Overview, challenges and perspectives. Signal Processing: Image Communication, 90:116015, 2021. 1" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 53, + 318, + 288, + 350 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 318, + 288, + 350 + ], + "spans": [ + { + "bbox": [ + 53, + 318, + 288, + 350 + ], + "type": "text", + "content": "[7] Richard Hartley and Andrew Zisserman. Multiple view geometry in computer vision. Cambridge university press, 2003. 3" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 53, + 352, + 288, + 396 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 352, + 288, + 396 + ], + "spans": [ + { + "bbox": [ + 53, + 352, + 288, + 396 + ], + "type": "text", + "content": "[8] Mingbo Hong, Yuhang Lu, Nianjin Ye, Chunyu Lin, Qijun Zhao, and Shuaicheng Liu. Unsupervised homography estimation with coplanarity-aware gan. In Proc. CVPR, pages 17663-17672, 2022. 1, 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 53, + 397, + 288, + 418 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 53, + 397, + 288, + 418 + ], + "spans": [ + { + "bbox": [ + 53, + 397, + 288, + 418 + ], + "type": "text", + "content": "[9] Jie Hu, Li Shen, and Gang Sun. Squeeze-and-excitation networks. In Proc. CVPR, pages 7132-7141, 2018. 4" + } + ] + } + ], + "index": 9 + }, + { + "bbox": [ + 48, + 420, + 288, + 453 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 420, + 288, + 453 + ], + "spans": [ + { + "bbox": [ + 48, + 420, + 288, + 453 + ], + "type": "text", + "content": "[10] Chia-Hung Huang, Hang Yin, Yu-Wing Tai, and Chi-Keung Tang. Stablenet: semi-online, multi-scale deep video stabilization. arXiv preprint arXiv:1907.10283, 2019. 4" + } + ] + } + ], + "index": 10 + }, + { + "bbox": [ + 48, + 454, + 288, + 486 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 454, + 288, + 486 + ], + "spans": [ + { + "bbox": [ + 48, + 454, + 288, + 486 + ], + "type": "text", + "content": "[11] Maria Silvia Ito and Ebroul Izquierdo. A dataset and evaluation framework for deep learning based video stabilization systems. In Proc. VCIP, pages 1-4. IEEE, 2019. 4" + } + ] + } + ], + "index": 11 + }, + { + "bbox": [ + 48, + 488, + 288, + 532 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 488, + 288, + 532 + ], + "spans": [ + { + "bbox": [ + 48, + 488, + 288, + 532 + ], + "type": "text", + "content": "[12] Dengchao Jin, Jianjun Lei, Bo Peng, Wanqing Li, Nam Ling, and Qingming Huang. Deep affine motion compensation network for inter prediction in vvc. IEEE Trans. on Circuits and Systems for Video Technology, 32(6):3923-3933, 2021. 1" + } + ] + } + ], + "index": 12 + }, + { + "bbox": [ + 48, + 533, + 288, + 576 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 533, + 288, + 576 + ], + "spans": [ + { + "bbox": [ + 48, + 533, + 288, + 576 + ], + "type": "text", + "content": "[13] Neel Joshi, Wolf Kienzle, Mike Toelle, Matt Uytendaele, and Michael F Cohen. Real-time hyperlapse creation via optimal frame selection. ACM Transactions on Graphics (TOG), 34(4):1-9, 2015. 3" + } + ] + } + ], + "index": 13 + }, + { + "bbox": [ + 48, + 578, + 288, + 611 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 578, + 288, + 611 + ], + "spans": [ + { + "bbox": [ + 48, + 578, + 288, + 611 + ], + "type": "text", + "content": "[14] Alexandre Karpenko, David Jacobs, Jongmin Baek, and Marc Levoy. Digital video stabilization and rolling shutter correction using gyroscopes. CSTR, 1(2):13, 2011. 3" + } + ] + } + ], + "index": 14 + }, + { + "bbox": [ + 48, + 613, + 288, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 613, + 288, + 634 + ], + "spans": [ + { + "bbox": [ + 48, + 613, + 288, + 634 + ], + "type": "text", + "content": "[15] Johannes Kopf. 360 video stabilization. ACM Transactions on Graphics (TOG), 35(6):1-9, 2016. 3" + } + ] + } + ], + "index": 15 + }, + { + "bbox": [ + 48, + 635, + 288, + 668 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 635, + 288, + 668 + ], + "spans": [ + { + "bbox": [ + 48, + 635, + 288, + 668 + ], + "type": "text", + "content": "[16] Ken-Yi Lee, Yung-Yu Chuang, Bing-Yu Chen, and Ming Ouhyoung. Video stabilization using robust feature trajectories. In Proc. CVPR, pages 1397-1404, 2009. 2" + } + ] + } + ], + "index": 16 + }, + { + "bbox": [ + 48, + 670, + 288, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 670, + 288, + 713 + ], + "spans": [ + { + "bbox": [ + 48, + 670, + 288, + 713 + ], + "type": "text", + "content": "[17] Yao-Chih Lee, Kuan-Wei Tseng, Yu-Ta Chen, Chien-Cheng Chen, Chu-Song Chen, and Yi-Ping Hung. 3d video stabilization with depth estimation by cnn-based optimization. In Proc. CVPR, pages 10621–10630, 2021. 1" + } + ] + } + ], + "index": 17 + } + ], + "sub_type": "ref_text" + }, + { + "bbox": [ + 307, + 73, + 545, + 713 + ], + "type": "list", + "angle": 0, + "index": 36, + "blocks": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "spans": [ + { + "bbox": [ + 307, + 73, + 545, + 106 + ], + "type": "text", + "content": "[18] Feng Liu, Michael Gleicher, Hailin Jin, and Aseem Agarwala. Content-preserving warps for 3d video stabilization. ACM Trans. on Graphics (ToG), 28(3):1-9, 2009. 1, 3" + } + ] + } + ], + "index": 19 + }, + { + "bbox": [ + 307, + 108, + 545, + 140 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 108, + 545, + 140 + ], + "spans": [ + { + "bbox": [ + 307, + 108, + 545, + 140 + ], + "type": "text", + "content": "[19] Feng Liu, Michael Gleicher, Jue Wang, Hailin Jin, and Aseem Agarwala. Subspace video stabilization. ACM Trans. on Graphics (TOG), 30(1):1-10, 2011. 3" + } + ] + } + ], + "index": 20 + }, + { + "bbox": [ + 307, + 141, + 545, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 141, + 545, + 184 + ], + "spans": [ + { + "bbox": [ + 307, + 141, + 545, + 184 + ], + "type": "text", + "content": "[20] Shuaicheng Liu, Mingyu Li, Shuyuan Zhu, and Bing Zeng. Codingflow: Enable video coding for video stabilization. IEEE Trans. on Image Processing, 26(7):3291-3302, 2017. 1, 3" + } + ] + } + ], + "index": 21 + }, + { + "bbox": [ + 307, + 186, + 545, + 239 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 186, + 545, + 239 + ], + "spans": [ + { + "bbox": [ + 307, + 186, + 545, + 239 + ], + "type": "text", + "content": "[21] Shuaicheng Liu, Yuhang Lu, Hai Jiang, Nianjin Ye, Chuan Wang, and Bing Zeng. Unsupervised global and local homography estimation with motion basis learning. IEEE Trans. on Pattern Analysis and Machine Intelligence, 2022. 1" + } + ] + } + ], + "index": 22 + }, + { + "bbox": [ + 307, + 240, + 545, + 274 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 240, + 545, + 274 + ], + "spans": [ + { + "bbox": [ + 307, + 240, + 545, + 274 + ], + "type": "text", + "content": "[22] Shuaicheng Liu, Ping Tan, Lu Yuan, Jian Sun, and Bing Zeng. Meshflow: Minimum latency online video stabilization. In Proc. ECCV, pages 800-815, 2016. 1, 2, 3, 6, 7" + } + ] + } + ], + "index": 23 + }, + { + "bbox": [ + 307, + 276, + 545, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 276, + 545, + 308 + ], + "spans": [ + { + "bbox": [ + 307, + 276, + 545, + 308 + ], + "type": "text", + "content": "[23] Shuaicheng Liu, Yinting Wang, Lu Yuan, Jiajun Bu, Ping Tan, and Jian Sun. Video stabilization with a depth camera. In Proc. CVPR, pages 89-95, 2012. 1, 3" + } + ] + } + ], + "index": 24 + }, + { + "bbox": [ + 307, + 309, + 545, + 352 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 309, + 545, + 352 + ], + "spans": [ + { + "bbox": [ + 307, + 309, + 545, + 352 + ], + "type": "text", + "content": "[24] Shuaicheng Liu, Nianjin Ye, Chuan Wang, Kunming Luo, Jue Wang, and Jian Sun. Content-aware unsupervised deep homography estimation and beyond. IEEE Trans. on Pattern Analysis and Machine Intelligence, 2022. 1" + } + ] + } + ], + "index": 25 + }, + { + "bbox": [ + 307, + 354, + 545, + 387 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 354, + 545, + 387 + ], + "spans": [ + { + "bbox": [ + 307, + 354, + 545, + 387 + ], + "type": "text", + "content": "[25] Shuaicheng Liu, Lu Yuan, Ping Tan, and Jian Sun. Bundled camera paths for video stabilization. ACM Trans. on Graphics (TOG), 32(4):1-10, 2013. 1, 2, 3, 6, 7" + } + ] + } + ], + "index": 26 + }, + { + "bbox": [ + 307, + 388, + 545, + 421 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 388, + 545, + 421 + ], + "spans": [ + { + "bbox": [ + 307, + 388, + 545, + 421 + ], + "type": "text", + "content": "[26] Shuaicheng Liu, Lu Yuan, Ping Tan, and Jian Sun. Steadyflow: Spatially smooth optical flow for video stabilization. In Proc. CVPR, pages 4209-4216, 2014. 1, 2, 3" + } + ] + } + ], + "index": 27 + }, + { + "bbox": [ + 307, + 422, + 545, + 465 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 422, + 545, + 465 + ], + "spans": [ + { + "bbox": [ + 307, + 422, + 545, + 465 + ], + "type": "text", + "content": "[27] Yasuyuki Matsushita, Eyal Ofek, Weina Ge, Xiaou Tang, and Heung-Yeung Shum. Full-frame video stabilization with motion inpainting. IEEE Trans. on Pattern Analysis and Machine Intelligence, 28(7):1150-1163, 2006. 1, 2" + } + ] + } + ], + "index": 28 + }, + { + "bbox": [ + 307, + 467, + 545, + 510 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 467, + 545, + 510 + ], + "spans": [ + { + "bbox": [ + 307, + 467, + 545, + 510 + ], + "type": "text", + "content": "[28] Lang Nie, Chunyu Lin, Kang Liao, Shuaicheng Liu, and Yao Zhao. Depth-aware multi-grid deep homography estimation with contextual correlation. IEEE Trans. on Circuits and Systems for Video Technology, 32(7):4460-4472, 2022. 1" + } + ] + } + ], + "index": 29 + }, + { + "bbox": [ + 307, + 512, + 545, + 544 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 512, + 545, + 544 + ], + "spans": [ + { + "bbox": [ + 307, + 512, + 545, + 544 + ], + "type": "text", + "content": "[29] Hui Qu, Li Song, and Gengjian Xue. Shaking video synthesis for video stabilization performance assessment. In Proc. VCIP, pages 1-6. IEEE, 2013. 4" + } + ] + } + ], + "index": 30 + }, + { + "bbox": [ + 307, + 545, + 545, + 578 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 545, + 545, + 578 + ], + "spans": [ + { + "bbox": [ + 307, + 545, + 545, + 578 + ], + "type": "text", + "content": "[30] Ethan Rublee, Vincent Rabaud, Kurt Konolige, and Gary Bradski. Orb: An efficient alternative to sift or surf. In Proc. ICCV, pages 2564-2571, 2011. 2" + } + ] + } + ], + "index": 31 + }, + { + "bbox": [ + 307, + 579, + 545, + 601 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 579, + 545, + 601 + ], + "spans": [ + { + "bbox": [ + 307, + 579, + 545, + 601 + ], + "type": "text", + "content": "[31] Jianbo Shi et al. Good features to track. In Proc. CVPR, pages 593-600, 1994. 2" + } + ] + } + ], + "index": 32 + }, + { + "bbox": [ + 307, + 602, + 545, + 634 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 602, + 545, + 634 + ], + "spans": [ + { + "bbox": [ + 307, + 602, + 545, + 634 + ], + "type": "text", + "content": "[32] Brandon M Smith, Li Zhang, Hailin Jin, and Aseem Agarwala. Light field video stabilization. In Proc. ICCV, pages 341-348, 2009. 3" + } + ] + } + ], + "index": 33 + }, + { + "bbox": [ + 307, + 635, + 545, + 689 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 635, + 545, + 689 + ], + "spans": [ + { + "bbox": [ + 307, + 635, + 545, + 689 + ], + "type": "text", + "content": "[33] Miao Wang, Guo-Ye Yang, Jin-Kun Lin, Song-Hai Zhang, Ariel Shamir, Shao-Ping Lu, and Shi-Min Hu. Deep online video stabilization with multi-grid warping transformation learning. IEEE Trans. on Image Processing, 28(5):2283-2292, 2018. 1, 2, 3, 4, 5, 6, 7, 8" + } + ] + } + ], + "index": 34 + }, + { + "bbox": [ + 307, + 691, + 545, + 713 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 307, + 691, + 545, + 713 + ], + "spans": [ + { + "bbox": [ + 307, + 691, + 545, + 713 + ], + "type": "text", + "content": "[34] Yu-Shuen Wang, Feng Liu, Pu-Sheng Hsu, and Tong-Yee Lee. Spatially and temporally optimized video stabiliza" + } + ] + } + ], + "index": 35 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 318, + 757 + ], + "type": "text", + "content": "23038" + } + ] + } + ], + "index": 37 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 8 + }, + { + "para_blocks": [ + { + "bbox": [ + 48, + 72, + 287, + 444 + ], + "type": "list", + "angle": 0, + "index": 10, + "blocks": [ + { + "bbox": [ + 67, + 72, + 286, + 95 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 67, + 72, + 286, + 95 + ], + "spans": [ + { + "bbox": [ + 67, + 72, + 286, + 95 + ], + "type": "text", + "content": "tion. IEEE Trans. on Visualization and Computer Graphics, 19(8):1354-1361, 2013. 2, 3" + } + ] + } + ], + "index": 0 + }, + { + "bbox": [ + 48, + 96, + 287, + 139 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 96, + 287, + 139 + ], + "spans": [ + { + "bbox": [ + 48, + 96, + 287, + 139 + ], + "type": "text", + "content": "[35] Sen-Zhe Xu, Jun Hu, Miao Wang, Tai-Jiang Mu, and ShiMin Hu. Deep video stabilization using adversarial networks. In Computer Graphics Forum, volume 37, pages 267-276, 2018. 1, 3" + } + ] + } + ], + "index": 1 + }, + { + "bbox": [ + 48, + 141, + 287, + 184 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 141, + 287, + 184 + ], + "spans": [ + { + "bbox": [ + 48, + 141, + 287, + 184 + ], + "type": "text", + "content": "[36] Yufei Xu, Jing Zhang, Stephen J Maybank, and Dacheng Tao. Dut: Learning video stabilization by simply watching unstable videos. IEEE Trans. on Image Processing, 31:4306-4320, 2022. 6" + } + ] + } + ], + "index": 2 + }, + { + "bbox": [ + 48, + 186, + 287, + 218 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 186, + 287, + 218 + ], + "spans": [ + { + "bbox": [ + 48, + 186, + 287, + 218 + ], + "type": "text", + "content": "[37] Junlan Yang, Dan Schonfeld, Chong Chen, and Magdi Mohamed. Online video stabilization based on particle filters. In Proc. ICIP, pages 1545-1548, 2006. 3" + } + ] + } + ], + "index": 3 + }, + { + "bbox": [ + 48, + 220, + 287, + 262 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 220, + 287, + 262 + ], + "spans": [ + { + "bbox": [ + 48, + 220, + 287, + 262 + ], + "type": "text", + "content": "[38] Nianjin Ye, Chuan Wang, Haoqiang Fan, and Shuaicheng Liu. Motion basis learning for unsupervised deep homography estimation with subspace projection. In Proc. ICCV, pages 13117-13125, October 2021. 1, 3" + } + ] + } + ], + "index": 4 + }, + { + "bbox": [ + 48, + 264, + 287, + 308 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 264, + 287, + 308 + ], + "spans": [ + { + "bbox": [ + 48, + 264, + 287, + 308 + ], + "type": "text", + "content": "[39] Nianjin Ye, Chuan Wang, Shuaicheng Liu, Lanpeng Jia, Jue Wang, and Yongqing Cui. Deepmeshflow: Content adaptive mesh deformation for robust image registration. arXiv preprint arXiv:1912.05131, 2019. 1, 2, 3, 4, 5" + } + ] + } + ], + "index": 5 + }, + { + "bbox": [ + 48, + 309, + 287, + 342 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 309, + 287, + 342 + ], + "spans": [ + { + "bbox": [ + 48, + 309, + 287, + 342 + ], + "type": "text", + "content": "[40] Jiyang Yu and Ravi Ramamoorthi. Robust video stabilization by optimization in cnn weight space. In Proc. CVPR, pages 3800-3808, 2019. 3" + } + ] + } + ], + "index": 6 + }, + { + "bbox": [ + 48, + 343, + 287, + 375 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 343, + 287, + 375 + ], + "spans": [ + { + "bbox": [ + 48, + 343, + 287, + 375 + ], + "type": "text", + "content": "[41] Jiyang Yu and Ravi Ramamoorthi. Learning video stabilization using optical flow. In Proc. CVPR, pages 8159-8167, 2020. 1, 3, 6" + } + ] + } + ], + "index": 7 + }, + { + "bbox": [ + 48, + 377, + 286, + 409 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 377, + 286, + 409 + ], + "spans": [ + { + "bbox": [ + 48, + 377, + 286, + 409 + ], + "type": "text", + "content": "[42] Jiyang Yu, Ravi Ramamoorthi, Keli Cheng, Michel Sarkis, and Ning Bi. Real-time selfie video stabilization. In Proc. CVPR, pages 12036-12044, 2021. 3" + } + ] + } + ], + "index": 8 + }, + { + "bbox": [ + 48, + 411, + 287, + 444 + ], + "type": "ref_text", + "angle": 0, + "lines": [ + { + "bbox": [ + 48, + 411, + 287, + 444 + ], + "spans": [ + { + "bbox": [ + 48, + 411, + 287, + 444 + ], + "type": "text", + "content": "[43] Minda Zhao and Qiang Ling. Pwstablenet: Learning pixelwise warping maps for video stabilization. IEEE Trans. on Image Processing, 29:3582-3595, 2020. 6, 7, 8" + } + ] + } + ], + "index": 9 + } + ], + "sub_type": "ref_text" + } + ], + "discarded_blocks": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "page_number", + "angle": 0, + "lines": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "spans": [ + { + "bbox": [ + 293, + 748, + 317, + 757 + ], + "type": "text", + "content": "23039" + } + ] + } + ], + "index": 11 + } + ], + "page_size": [ + 612, + 792 + ], + "page_idx": 9 + } + ], + "_backend": "vlm", + "_version_name": "2.6.4" +} \ No newline at end of file